2012 Vol. 36 No. 2
Abstract：
The common carp (Cyprinus carpio L.), one of the most important species for aquaculture in China, is a widespread freshwater fish of eutrophic waters in lakes and large rivers. The wild populations are considered vulnerable to extinction, but the species has also been domesticated and introduced into environments worldwide, and is often considered as an invasive species. However, genetic degeneration, such as low growth rate, small body size, weak disease- resistance, etc., emerged in common carp with the rapid development of its farming scale. Quantitative traits (for example, the feed conversion ratio of common carp) refer to phenotypes that vary in degree and can be attributed to polygenic effects, i.e., product of two or more genes, and their environment. Quantitative trait loci (QTLs) are stretches of DNA containing or linked to the genes that underlie a quantitative trait. Mapping regions of the genome that contain genes involved in specifying a quantitative trait is done using molecular tags such as SSR, EST or more commonly SNPs. This is an early step in identifying and sequencing the actual genes underlying trait variation. Researches of genetic diversity, kin discrimination, strain identification, genetic linkage map construction, trait-related marker screening, genetic evaluation and QTL are the effective way to solve these problems of breeding in common carp. In this paper, a group of F2 hybrids German mirror carp including 68 individuals was used to construct a linkage map by using 560 markers (174 SSR markers, 41EST-SSR markers and 345 SNP markers). Quantitative traits loci (QTLs) associated with feed conversion ratio were identified by interval mapping and MQM mapping of the software MapQTL5.0. A linkage group wide permutation test (1000 replicates) determined the significance of the maximum LOD value over the various intervals analyzed for each linkage group. The results indicated that fifteen QTLs were identified for feed conversion ratio on nine linkage groups, which explained 17.70% and 52.20% of the total variation of feed conversion ratio, respectively. Two QTLs were associated with LG25 (HLJE314-SNP0919) and LG39 (HLJ1439-HLJ1438), which covered the lest 0.614 and most 24.922. There were two QTLs (HLJ1439-HLJ1438 and HLJ922-SNP0711), which explained over 50.00% of the total variation of the feed conversion ratio. They were major QTLs associated to the feed conversion of common carp. Three QTLs were negative additive effect with the average value of ?0.027, while the others positive additive effect with the average value of 0.06. The results also suggested that the feed conversion ratio traits should be determined by more than one loci which was conformed to the theory on quantitative genetics. This work investigated the correlation between markers and growth traits in common carp and obtained trait-related QTL and the results would be valuable for marker-assisted breeding in common carp.
The common carp (Cyprinus carpio L.), one of the most important species for aquaculture in China, is a widespread freshwater fish of eutrophic waters in lakes and large rivers. The wild populations are considered vulnerable to extinction, but the species has also been domesticated and introduced into environments worldwide, and is often considered as an invasive species. However, genetic degeneration, such as low growth rate, small body size, weak disease- resistance, etc., emerged in common carp with the rapid development of its farming scale. Quantitative traits (for example, the feed conversion ratio of common carp) refer to phenotypes that vary in degree and can be attributed to polygenic effects, i.e., product of two or more genes, and their environment. Quantitative trait loci (QTLs) are stretches of DNA containing or linked to the genes that underlie a quantitative trait. Mapping regions of the genome that contain genes involved in specifying a quantitative trait is done using molecular tags such as SSR, EST or more commonly SNPs. This is an early step in identifying and sequencing the actual genes underlying trait variation. Researches of genetic diversity, kin discrimination, strain identification, genetic linkage map construction, trait-related marker screening, genetic evaluation and QTL are the effective way to solve these problems of breeding in common carp. In this paper, a group of F2 hybrids German mirror carp including 68 individuals was used to construct a linkage map by using 560 markers (174 SSR markers, 41EST-SSR markers and 345 SNP markers). Quantitative traits loci (QTLs) associated with feed conversion ratio were identified by interval mapping and MQM mapping of the software MapQTL5.0. A linkage group wide permutation test (1000 replicates) determined the significance of the maximum LOD value over the various intervals analyzed for each linkage group. The results indicated that fifteen QTLs were identified for feed conversion ratio on nine linkage groups, which explained 17.70% and 52.20% of the total variation of feed conversion ratio, respectively. Two QTLs were associated with LG25 (HLJE314-SNP0919) and LG39 (HLJ1439-HLJ1438), which covered the lest 0.614 and most 24.922. There were two QTLs (HLJ1439-HLJ1438 and HLJ922-SNP0711), which explained over 50.00% of the total variation of the feed conversion ratio. They were major QTLs associated to the feed conversion of common carp. Three QTLs were negative additive effect with the average value of ?0.027, while the others positive additive effect with the average value of 0.06. The results also suggested that the feed conversion ratio traits should be determined by more than one loci which was conformed to the theory on quantitative genetics. This work investigated the correlation between markers and growth traits in common carp and obtained trait-related QTL and the results would be valuable for marker-assisted breeding in common carp.
2012, 36(2): 197-204.
DOI: 10.3724/SP.J.1035.2012.00197
Abstract：
Gobiocypris rarus is a small freshwater fish endemic to upper reaches of the Yangtze River. In China, the fish is being used as an aquatic laboratory animal mainly applied in researches on toxicology, fish pathology and genetics. Due to habitat loss and human activities, G. rarus is also considered as an endangered species listed in the China Red Data Book of Endangered Animals. Closed colony is an animal stock propagated by non-inbred within the stock, in which no genes are introduced from outside the stock from generation to generation. Because of high heterozygosity and stable genetic structure, closed colony animals are widely used in various researches. Therefore, foundation of a closed colony of G. rarus is the basis for its future laboratory use as well as species conservation. In the present study, we established a closed colony of G. rarus with 50 pairs of wild fish (P0) gathered in Hanyuan County, Sichuan Province. The stock propagated by maximum avoidance of inbreeding system for 4 generations (F1 to F4) was named as Ihb: IHB. Eleven microsatellite loci were used to monitoring the genetic variation among the generations. A total of 57 alleles were detected in the overall sample, while the number of alleles per locus, the effective number of alleles and the polymorphic information (PIC) averaged 5.2, 3.3 and 0.5282, respectively. For different generations of the closed colony, average expected heterozygosity (He) ranged from 0.5553 to 0.5742, and average PIC ranged from 0.5060 to 0.5318. No significant differences (P>0.05) on genetic diversity indices were detected among generations, including the averaged observed number of alleles (Na), average effective number of alleles (Ne), average observed heterozygosity (Ho), average expected heterozygosity (He) and average polymorphic information (PIC). Pairwise genetic similarities were over 0.99, implying closer genetic relationship and high genetic identity among generations. Analysis of molecular variance (AMOVA) revealed pairwise fixation index (FST) ranged from 0.0001 to 0.0031 with the overall FST value 0.0008 among generations, indicating that most of the genetic variance was among individuals rather than that of generations. Fisher's exact test on allele frequency showed no significant difference on any loci in successive generations (P>0.05). As a result, the genetic variation during the propagation of generations of G. rarus was successfully avoided and then high genetic diversity of the wild population was maintained in the strain. In other words, it indicated that Ihb: IHB of G. rarus fit the genetic quality of closed colony animal. Continuous reproductive strategy and genetic monitoring program should be carried out in order to use this newly established closed colony.
Gobiocypris rarus is a small freshwater fish endemic to upper reaches of the Yangtze River. In China, the fish is being used as an aquatic laboratory animal mainly applied in researches on toxicology, fish pathology and genetics. Due to habitat loss and human activities, G. rarus is also considered as an endangered species listed in the China Red Data Book of Endangered Animals. Closed colony is an animal stock propagated by non-inbred within the stock, in which no genes are introduced from outside the stock from generation to generation. Because of high heterozygosity and stable genetic structure, closed colony animals are widely used in various researches. Therefore, foundation of a closed colony of G. rarus is the basis for its future laboratory use as well as species conservation. In the present study, we established a closed colony of G. rarus with 50 pairs of wild fish (P0) gathered in Hanyuan County, Sichuan Province. The stock propagated by maximum avoidance of inbreeding system for 4 generations (F1 to F4) was named as Ihb: IHB. Eleven microsatellite loci were used to monitoring the genetic variation among the generations. A total of 57 alleles were detected in the overall sample, while the number of alleles per locus, the effective number of alleles and the polymorphic information (PIC) averaged 5.2, 3.3 and 0.5282, respectively. For different generations of the closed colony, average expected heterozygosity (He) ranged from 0.5553 to 0.5742, and average PIC ranged from 0.5060 to 0.5318. No significant differences (P>0.05) on genetic diversity indices were detected among generations, including the averaged observed number of alleles (Na), average effective number of alleles (Ne), average observed heterozygosity (Ho), average expected heterozygosity (He) and average polymorphic information (PIC). Pairwise genetic similarities were over 0.99, implying closer genetic relationship and high genetic identity among generations. Analysis of molecular variance (AMOVA) revealed pairwise fixation index (FST) ranged from 0.0001 to 0.0031 with the overall FST value 0.0008 among generations, indicating that most of the genetic variance was among individuals rather than that of generations. Fisher's exact test on allele frequency showed no significant difference on any loci in successive generations (P>0.05). As a result, the genetic variation during the propagation of generations of G. rarus was successfully avoided and then high genetic diversity of the wild population was maintained in the strain. In other words, it indicated that Ihb: IHB of G. rarus fit the genetic quality of closed colony animal. Continuous reproductive strategy and genetic monitoring program should be carried out in order to use this newly established closed colony.
2012, 36(2): 205-211.
DOI: 10.3724/SP.J.1035.2012.00205
Abstract：
The Sox genes family comprises several transcription factors that share a highly conserved HMG (High-Mobility-Group) box and has been studied in many species, including a variety of vertebrates and several of invertebrates such as fruit fly, nematode and Portunustrituberculatus. But there are only few reports on Sox gene family of freshwater bivalve so far, which have important value in evolution and production. H. schlegelii, which originated from Lake Biwa in Japan and was introduced into China in 1998, is one of the representative freshwater pearl mussels. It has been widely applied in the Chinese freshwater pearl industry for its high quality pearl bearing ability. In order to know the function of Sox genes in this mussel, a degenerate PCR, referred to the HMG box of human SRY gene, was used to amplify the conserved sequence of HMG domains of Sox genes. Two different HMG sequences were got from DNA and the testis cDNA, named DNA-HMG1, DNA-HMG2 and cDNA-HMG. Amino acids sequences analysis showed that those HMG sequences had high homology with the Sox1, Sox2, Sox3 and Sox14 genes from other animals including human being. But there showed no difference between the male and female. A partial cDNA sequence of Sox2 gene (refereed as hs-Sox2) with 1774 bp including partial ORF and complete 3' untranslated region (UTR) was cloned from the testis cDNA by RACE-PCR methods. DNA sequences analysis showed that it had high homology with the SoxB gene in Patella vulgata and the Sox2 gene in human being. The putative 249 amino acid sequence contained one conserved HMG box like the human SYR gene, and exhibited 98% homology with human, mouse, chicken and zebrafish. For further know the expression level of Sox2 gene, real-time PCR method was used to examine its mRNA level in different tissues and different months on testis of H. schlegelii. Results showed that the hs-Sox2 mRNA was ubiquitously expressed in all the tissues, with the highest in kidney, followed by intestine, adductor muscle, and the expression level in the testis was higher than that in the ovary. The result from the different months on testis revealed that hs-Sox2 was transcribed mainly in the 39 months, followed by 16 months and lowly in the 63 months. These results suggested that hs-Sox2 may be involved in the development of on testis in the H. schlegelii and may constitute clues for future work in order to better understand Sox protein.
The Sox genes family comprises several transcription factors that share a highly conserved HMG (High-Mobility-Group) box and has been studied in many species, including a variety of vertebrates and several of invertebrates such as fruit fly, nematode and Portunustrituberculatus. But there are only few reports on Sox gene family of freshwater bivalve so far, which have important value in evolution and production. H. schlegelii, which originated from Lake Biwa in Japan and was introduced into China in 1998, is one of the representative freshwater pearl mussels. It has been widely applied in the Chinese freshwater pearl industry for its high quality pearl bearing ability. In order to know the function of Sox genes in this mussel, a degenerate PCR, referred to the HMG box of human SRY gene, was used to amplify the conserved sequence of HMG domains of Sox genes. Two different HMG sequences were got from DNA and the testis cDNA, named DNA-HMG1, DNA-HMG2 and cDNA-HMG. Amino acids sequences analysis showed that those HMG sequences had high homology with the Sox1, Sox2, Sox3 and Sox14 genes from other animals including human being. But there showed no difference between the male and female. A partial cDNA sequence of Sox2 gene (refereed as hs-Sox2) with 1774 bp including partial ORF and complete 3' untranslated region (UTR) was cloned from the testis cDNA by RACE-PCR methods. DNA sequences analysis showed that it had high homology with the SoxB gene in Patella vulgata and the Sox2 gene in human being. The putative 249 amino acid sequence contained one conserved HMG box like the human SYR gene, and exhibited 98% homology with human, mouse, chicken and zebrafish. For further know the expression level of Sox2 gene, real-time PCR method was used to examine its mRNA level in different tissues and different months on testis of H. schlegelii. Results showed that the hs-Sox2 mRNA was ubiquitously expressed in all the tissues, with the highest in kidney, followed by intestine, adductor muscle, and the expression level in the testis was higher than that in the ovary. The result from the different months on testis revealed that hs-Sox2 was transcribed mainly in the 39 months, followed by 16 months and lowly in the 63 months. These results suggested that hs-Sox2 may be involved in the development of on testis in the H. schlegelii and may constitute clues for future work in order to better understand Sox protein.
Abstract：
Vibrio harveyi is one of the important bacterial pathogens of marine animals. Superoxide dismutases, which abate and clear the effect of O2- via catalyse dismutation of superoxide into hydrogen peroxide and oxygen, belong to the anti-oxidation defense system and play a central role in protection against oxidative stress. An iron-cofactored superoxide dismutase gene was cloned by PCR amplification from the chromosomal DNA of V. harveyi SF1. The ORF of the sod gene consists of 600 bp, Sequence analysis showed that homologies of the amino acid sequence with those of Fe-SOD ranged from 91% to 99%. The sod gene was subcloned into pET26b (+) for experssion. SDS-PAGE confirmed that the purified protein was 27 kD. The purified SOD belonged to Fe-SOD based on the analysis of sensitivity to hydrogen peroxid, chlorofrom-ethanol and ultraviolet-visible spectroscopy. Pyorgallol autoxidation method was used to determine SOD activity of the purified protein. The purified SOD had the maximal activity at pH 7 and was stable over a range of pH 6—8. The optimal temperature for enzyme activity was 20 . The protein ℃ n was stable under 40℃. Turbots (Scophthalmus maximus) were immunized with 50 ug of the purified SOD. The immunized fish were then challenged with 0.1 mL of V. harveyi (3.9×108 CFU/mL) four weeks later. The relative percentage survivals (RPS) of the immunized group were 80.00%. Specific antibody could be detected in the sera of the immunized fish with Western blot analysis.
Vibrio harveyi is one of the important bacterial pathogens of marine animals. Superoxide dismutases, which abate and clear the effect of O2- via catalyse dismutation of superoxide into hydrogen peroxide and oxygen, belong to the anti-oxidation defense system and play a central role in protection against oxidative stress. An iron-cofactored superoxide dismutase gene was cloned by PCR amplification from the chromosomal DNA of V. harveyi SF1. The ORF of the sod gene consists of 600 bp, Sequence analysis showed that homologies of the amino acid sequence with those of Fe-SOD ranged from 91% to 99%. The sod gene was subcloned into pET26b (+) for experssion. SDS-PAGE confirmed that the purified protein was 27 kD. The purified SOD belonged to Fe-SOD based on the analysis of sensitivity to hydrogen peroxid, chlorofrom-ethanol and ultraviolet-visible spectroscopy. Pyorgallol autoxidation method was used to determine SOD activity of the purified protein. The purified SOD had the maximal activity at pH 7 and was stable over a range of pH 6—8. The optimal temperature for enzyme activity was 20 . The protein ℃ n was stable under 40℃. Turbots (Scophthalmus maximus) were immunized with 50 ug of the purified SOD. The immunized fish were then challenged with 0.1 mL of V. harveyi (3.9×108 CFU/mL) four weeks later. The relative percentage survivals (RPS) of the immunized group were 80.00%. Specific antibody could be detected in the sera of the immunized fish with Western blot analysis.
Abstract：
Generally, olfactory organs and olfactory nerves of the left and right side in vertebrate are separate completely. Even for single nose-type cyclostomes, such as lampreys, their olfactory nerves are also separate completely. Furthermore, their anterior and posterior nostril (or choana), olfactory cavity, and cavity of olfactory accessory sac all communicate with each others, and the organs are usually open in whole. They usually have olfactory cavities, whose volume is relatively larger and steadier, and their olfactory epithelia primarily locate on one side of the cavities. Moreover, there is usually no lacuna in fish between their olfactory sacs and nasal pits.
Generally, olfactory organs and olfactory nerves of the left and right side in vertebrate are separate completely. Even for single nose-type cyclostomes, such as lampreys, their olfactory nerves are also separate completely. Furthermore, their anterior and posterior nostril (or choana), olfactory cavity, and cavity of olfactory accessory sac all communicate with each others, and the organs are usually open in whole. They usually have olfactory cavities, whose volume is relatively larger and steadier, and their olfactory epithelia primarily locate on one side of the cavities. Moreover, there is usually no lacuna in fish between their olfactory sacs and nasal pits.
2012, 36(2): 229-235.
DOI: 10.3724/SP.J.1035.2012.00229
Abstract：
Gibel carp (Carassius auratus gibelio), a unique polyploid fish, is discovered to be able to reproduce by gynogenesis or sexuality reproduction. Since the allotetraploid gibel carp with 212 chromosomes were discovered from the gynogenetic offspring of gibel carp activated by red common carp sperm in 1990s, a lot of works have be done to study the genome organization and formation mechanism of them. The observations of genomic in situ hybridization and 45S rRNA gene localization on the allopolyploid metaphases showed the unusual allotetraploid gibel carp which contain the whole chromosomes of gibel carp and one chromosome set of common carp. However, the histological characterizations of allotetraploid gibel carp still remain unknown. In this study, we compared the histological features and found significant differences in peripheral blood cells and testis tissues between triploid (D clone) and allotetraploid gibel carp. The HE staining results showed that there were many abnormal red blood cells with small, round nuclear in the blood cell smear of allotetraploid gibel carp, which was obviously different from red blood cells with oval-shaped nuclear of triploid gibel carp. Moreover, the dual-nuclear red blood cells indicated a trend of cell division in peripheral blood of the allotetraploid gibel carp. Meanwhile, using the flow cytometry technique, we compared the DNA histogram of peripheral blood cells between triploid and allotetraploid gibel carp. The result revealed the existence of two kinds of cells with different DNA content in peripheral blood of allotetraploid gibel carp. In addition, we observed three testis types of allotetraploid gibel carp: TypeⅠ, wild type, which the sperm development was as normal as that of the male D clone gibel carp and large quantity of spermatids and sperms could be found in spermatogenic cysts; TypeⅡ, in which spermatids and sperms could not be observed in spermatogenic cysts; and Type Ⅲ, lacking the structure of spermatogenic cysts. Among those three types, TypeⅡ and type Ⅲ were the mainly forms of testis in allotetraploid gibel carp. To further study the characterizations of sperm development, fluorescent immunostaining was performed to compare different testis types of allotetraploid gibel carp by using the vasa antibody. The result revealed that germ cells in TypeⅠtestis could complete the meiosis process and produce a large number of spermatids and sperms in breeding season, while TypeⅡ testis was observed considerable quantities of primary and secondary speratocytes without spermatids in its spermatogenic cysts, indicating that germ cells cannot complete the second meiosis process in TypeⅡ testis. The unique characterization of red blood cell and testis could broaden our understanding about allotetraploid gibel carp.
Gibel carp (Carassius auratus gibelio), a unique polyploid fish, is discovered to be able to reproduce by gynogenesis or sexuality reproduction. Since the allotetraploid gibel carp with 212 chromosomes were discovered from the gynogenetic offspring of gibel carp activated by red common carp sperm in 1990s, a lot of works have be done to study the genome organization and formation mechanism of them. The observations of genomic in situ hybridization and 45S rRNA gene localization on the allopolyploid metaphases showed the unusual allotetraploid gibel carp which contain the whole chromosomes of gibel carp and one chromosome set of common carp. However, the histological characterizations of allotetraploid gibel carp still remain unknown. In this study, we compared the histological features and found significant differences in peripheral blood cells and testis tissues between triploid (D clone) and allotetraploid gibel carp. The HE staining results showed that there were many abnormal red blood cells with small, round nuclear in the blood cell smear of allotetraploid gibel carp, which was obviously different from red blood cells with oval-shaped nuclear of triploid gibel carp. Moreover, the dual-nuclear red blood cells indicated a trend of cell division in peripheral blood of the allotetraploid gibel carp. Meanwhile, using the flow cytometry technique, we compared the DNA histogram of peripheral blood cells between triploid and allotetraploid gibel carp. The result revealed the existence of two kinds of cells with different DNA content in peripheral blood of allotetraploid gibel carp. In addition, we observed three testis types of allotetraploid gibel carp: TypeⅠ, wild type, which the sperm development was as normal as that of the male D clone gibel carp and large quantity of spermatids and sperms could be found in spermatogenic cysts; TypeⅡ, in which spermatids and sperms could not be observed in spermatogenic cysts; and Type Ⅲ, lacking the structure of spermatogenic cysts. Among those three types, TypeⅡ and type Ⅲ were the mainly forms of testis in allotetraploid gibel carp. To further study the characterizations of sperm development, fluorescent immunostaining was performed to compare different testis types of allotetraploid gibel carp by using the vasa antibody. The result revealed that germ cells in TypeⅠtestis could complete the meiosis process and produce a large number of spermatids and sperms in breeding season, while TypeⅡ testis was observed considerable quantities of primary and secondary speratocytes without spermatids in its spermatogenic cysts, indicating that germ cells cannot complete the second meiosis process in TypeⅡ testis. The unique characterization of red blood cell and testis could broaden our understanding about allotetraploid gibel carp.
2012, 36(2): 236-245.
DOI: 10.3724/SP.J.1035.2012.00236
Abstract：
Panulirus ornatus is one of the most valuable seafood commodities in the world. This species is also the largest tropical lobster for fisheries and culture in China. But now the natural resources of P. ornatus is shortage, and culture from egg through the larval phase to puerulus has not been completed. Hence, the research for artificial breeding to protect the proliferation and resources is needed. In this paper, the artificial propagation of 26 months old cultured Panulirus ornatus and development of the embryos were studied. The results showed that the cultured P. ornatus could breed twice in five months. The ovarian maturation can be accelerated by ablating the unilateral eyestalk. During the first and second brooding, the ovarian maturation time of the eyestalk-ablated females was shortened by 17.7 d and 11.3 d, respectively, comparing with the control group. The females spawn 1–10 days post mating. During the first and second brood, the numbers of eggs per female produced were average of 40.34 × 104 and 32.97 × 104 with mean hatch rates of 77.29% and 77.72%, and average 31.70 × 104 and 25.38 × 104 phyllosoma were successfully hatched, respectively. The embryos developed for 22–23 d at water temperature of 29.2 and salinity of 30. The process of embryonic ℃ development could be divided into eleven stages: fertilized eggs, cleavage stage, blastula stage, gastrula stage, egg-nauplius stage, embryo with 7 pairs of appendages, embryo with 9 pairs of appendages, embryo with 11 pairs of appendages, embryo with compound eye pigments formed, pre-hatching stage and hatching stage．
Panulirus ornatus is one of the most valuable seafood commodities in the world. This species is also the largest tropical lobster for fisheries and culture in China. But now the natural resources of P. ornatus is shortage, and culture from egg through the larval phase to puerulus has not been completed. Hence, the research for artificial breeding to protect the proliferation and resources is needed. In this paper, the artificial propagation of 26 months old cultured Panulirus ornatus and development of the embryos were studied. The results showed that the cultured P. ornatus could breed twice in five months. The ovarian maturation can be accelerated by ablating the unilateral eyestalk. During the first and second brooding, the ovarian maturation time of the eyestalk-ablated females was shortened by 17.7 d and 11.3 d, respectively, comparing with the control group. The females spawn 1–10 days post mating. During the first and second brood, the numbers of eggs per female produced were average of 40.34 × 104 and 32.97 × 104 with mean hatch rates of 77.29% and 77.72%, and average 31.70 × 104 and 25.38 × 104 phyllosoma were successfully hatched, respectively. The embryos developed for 22–23 d at water temperature of 29.2 and salinity of 30. The process of embryonic ℃ development could be divided into eleven stages: fertilized eggs, cleavage stage, blastula stage, gastrula stage, egg-nauplius stage, embryo with 7 pairs of appendages, embryo with 9 pairs of appendages, embryo with 11 pairs of appendages, embryo with compound eye pigments formed, pre-hatching stage and hatching stage．
2012, 36(2): 246-254.
DOI: 10.3724/SP.J.1035.2012.00246
Abstract：
The Poyang Lake in Jiangxi Province is an important habitat of the Yangtze finless porpoises. There are about 400 individuals of porpoise inhabiting in the lake. The surveys conducted in recent years indicated that one of the threats faced by the animals might be from the heavy boat traffic in the lake. For estimating the possible negative effects of the boat traffic on the animals in the lake, an acoustic observation with the aid of an underwater acoustic data logger was conducted in the confluence of Poyang Lake and the Yangtze River from 27 June to 1 July 2007. In this observation, the passive acoustic data logger was fixed at the monitor station (latitude: 29°42′38″ N, longitude: 116°11′11″ E) and was deployed to monitor and record continually periphery underwater noise of the boat traffic and pulse events of sonar signals of porpoises that presented within 300 m around the station. During the 109h of investigation, 494 vessels and 13,413 click trains were recorded by the logger. These data were analyzed by using a customized program developed on Igor Pro 5.01 (WaveMetrics, USA), and the results were used for investigating the effects of boat traffic on the acoustic behavior of finless porpoises in the waters. A weak negative correlation between the presence of porpoises and ships was observed (r = -0.029, N = 6550, P Z = -0.370, P > 0.05). The phonation rate of click trains recorded by the acoustic data logger declined significantly during the vessel present (in-noise) situations (Z = -10.050, P Z = -0.275, P > 0.05; Z = -0.119, P > 0.05). No significant differences were observed in the phonation rate of click trains, the duration of click trains, as well as the inter-click intervals of the porpoises among pre-, during, and post-boat encounters (χ2= 5.255, P > 0.05; χ2= 3.511, P > 0.05; χ2= 5.155, P > 0.05). The porpoises did not have any preference for swimming direction during the encounters of ships (χ2= 0.861, P > 0.05). Although the porpoises have certain sensitivity in behavioral responses to presence of boats, the animals did not show distinct avoiding behaviors when encountering boats in the waters with little width. The results of this study seem to indicate that the porpoises in the narrow channel usually take “temporary” strategy to response the disturbance from the boat traffic. Additionally, boat traffic is the most frequently encountering of the porpoises in the waters, and it might result in the porpoises have certain “acoustic adaptation” to its presence, and therefore the animals do not show intensive acoustic responses to the noise from the boat traffic. It will be needed to conduct more observations on the behavior responses of the porpoises to boat presence in different waters with different size by using the acoustic observation system, and make further estimation about the avoiding behavior and acoustic responses of the porpoises to boat traffic.
The Poyang Lake in Jiangxi Province is an important habitat of the Yangtze finless porpoises. There are about 400 individuals of porpoise inhabiting in the lake. The surveys conducted in recent years indicated that one of the threats faced by the animals might be from the heavy boat traffic in the lake. For estimating the possible negative effects of the boat traffic on the animals in the lake, an acoustic observation with the aid of an underwater acoustic data logger was conducted in the confluence of Poyang Lake and the Yangtze River from 27 June to 1 July 2007. In this observation, the passive acoustic data logger was fixed at the monitor station (latitude: 29°42′38″ N, longitude: 116°11′11″ E) and was deployed to monitor and record continually periphery underwater noise of the boat traffic and pulse events of sonar signals of porpoises that presented within 300 m around the station. During the 109h of investigation, 494 vessels and 13,413 click trains were recorded by the logger. These data were analyzed by using a customized program developed on Igor Pro 5.01 (WaveMetrics, USA), and the results were used for investigating the effects of boat traffic on the acoustic behavior of finless porpoises in the waters. A weak negative correlation between the presence of porpoises and ships was observed (r = -0.029, N = 6550, P Z = -0.370, P > 0.05). The phonation rate of click trains recorded by the acoustic data logger declined significantly during the vessel present (in-noise) situations (Z = -10.050, P Z = -0.275, P > 0.05; Z = -0.119, P > 0.05). No significant differences were observed in the phonation rate of click trains, the duration of click trains, as well as the inter-click intervals of the porpoises among pre-, during, and post-boat encounters (χ2= 5.255, P > 0.05; χ2= 3.511, P > 0.05; χ2= 5.155, P > 0.05). The porpoises did not have any preference for swimming direction during the encounters of ships (χ2= 0.861, P > 0.05). Although the porpoises have certain sensitivity in behavioral responses to presence of boats, the animals did not show distinct avoiding behaviors when encountering boats in the waters with little width. The results of this study seem to indicate that the porpoises in the narrow channel usually take “temporary” strategy to response the disturbance from the boat traffic. Additionally, boat traffic is the most frequently encountering of the porpoises in the waters, and it might result in the porpoises have certain “acoustic adaptation” to its presence, and therefore the animals do not show intensive acoustic responses to the noise from the boat traffic. It will be needed to conduct more observations on the behavior responses of the porpoises to boat presence in different waters with different size by using the acoustic observation system, and make further estimation about the avoiding behavior and acoustic responses of the porpoises to boat traffic.
Abstract：
To test the swimming performance, locomotive limiting factors and metabolic adaptive strategy of darkbarbel catfish Peltebagrus vachelli under different dissolved oxygen levels (DO), the effects of DO (125%, 100%, 75%, 50% and 25% air saturation) on resting oxygen consumption rate (MO2), critical swimming speed (Ucrit) and MO2 at different swimming speeds up to Ucrit were investigated in juvenile darkbarbel catfish at 25oC. Resting MO2 decreased significantly with DO (P2]crit) for resting MO2 was 14.52% air saturation (1.16 mg/L). The active MO2 decreased significantly with the decrease of DO from 100% to 25% air saturation (PUcrit decreased significantly when DO fell below 75% air saturation (PUcrit nor active MO2 showed any elevation under hyperoxic conditions (125% air saturation); and the cost of transport (COT) was significantly lower under 25% air saturation than that of other groups at corresponding swimming speeds (P<0.05). These results suggested that the swimming performance of darkbarbel catfish was limited by the cardio-respiratory system under hypoxia, while it was limited by the peripheral locomotory organs and musculature under normoxia.
To test the swimming performance, locomotive limiting factors and metabolic adaptive strategy of darkbarbel catfish Peltebagrus vachelli under different dissolved oxygen levels (DO), the effects of DO (125%, 100%, 75%, 50% and 25% air saturation) on resting oxygen consumption rate (MO2), critical swimming speed (Ucrit) and MO2 at different swimming speeds up to Ucrit were investigated in juvenile darkbarbel catfish at 25oC. Resting MO2 decreased significantly with DO (P2]crit) for resting MO2 was 14.52% air saturation (1.16 mg/L). The active MO2 decreased significantly with the decrease of DO from 100% to 25% air saturation (PUcrit decreased significantly when DO fell below 75% air saturation (PUcrit nor active MO2 showed any elevation under hyperoxic conditions (125% air saturation); and the cost of transport (COT) was significantly lower under 25% air saturation than that of other groups at corresponding swimming speeds (P<0.05). These results suggested that the swimming performance of darkbarbel catfish was limited by the cardio-respiratory system under hypoxia, while it was limited by the peripheral locomotory organs and musculature under normoxia.
2012, 36(2): 262-269.
DOI: 10.3724/SP.J.1035.2012.00262
Abstract：
Rhinogobio cylindricus Günther is a cyprinid fish endemic to the upper reaches of the Yangtze River. The upper Yangtze River basin is experiencing critical changes to its ecosystem through multiple ecological threats in recent years, especially the impoundment of the Three Gorges Reservoir. R. cylindricus is a rheophilics species requiring diverse habitats to fulfill its life cycle. Otherwise the habitat once changed, life of R. cylindricus would be deeply affected. Therefore the study of age and growth, using scale, which is a basic and important aspect of fish biology and ecology, was essential to find out the growth characteristic of R. cylindricus after filling. The purpose of this study was to determine age structure and growth characteristics of R. cylindricus, and to propose reasonable measures to manage and protect this species. A total of 511 samples of R. cylindricus were collected from the upper reaches of the Yangtze River in Hejiang of Sichuan and Mudong of Chongqing from 2008 to 2010. The results showed that there were 6 age groups of our collected samples, and most individuals were 2—4 year-old accounting for about 95.7 percent of the total. According to the comparison of coefficient among linear function, exponential function, polynomial function and power function, and the relationship between body length (L) and scale radius (R) showed no significant difference between females and males, which could be expressed as L=51.28R+37.45 (r = 0.85, n = 397). And there was no significant difference between measured body length and back-calculated body length at each age group between females and males (t = 0.751, P > 0.05). Meanwhile, the relationship between body length (L) and body weight (W) showed no significant difference between females and males, and could be expressed as W= 8×10-6L3.099 (r = 0.97, n = 397). Von Bertalanffy growth function was Lt = 348.78 [1-e-0.18 (t +1.15)] and Wt = 603.17 [1-e-0.18 (t +1.15)]3.099. In addition, the age at the inflection point of body weight growth was 5.12 years old, when body length and body weight were 236.23 mm and 180.33 g, respectively. Besides, R. cylindricus was isometric growth and individual miniaturization. The exploitation of R. cylindricus in the upper of the Yangtze River was unreasonable, so we should take action to strictly ban catching in the future and strengthen scientific research on R. cylindricus to protect better.
Rhinogobio cylindricus Günther is a cyprinid fish endemic to the upper reaches of the Yangtze River. The upper Yangtze River basin is experiencing critical changes to its ecosystem through multiple ecological threats in recent years, especially the impoundment of the Three Gorges Reservoir. R. cylindricus is a rheophilics species requiring diverse habitats to fulfill its life cycle. Otherwise the habitat once changed, life of R. cylindricus would be deeply affected. Therefore the study of age and growth, using scale, which is a basic and important aspect of fish biology and ecology, was essential to find out the growth characteristic of R. cylindricus after filling. The purpose of this study was to determine age structure and growth characteristics of R. cylindricus, and to propose reasonable measures to manage and protect this species. A total of 511 samples of R. cylindricus were collected from the upper reaches of the Yangtze River in Hejiang of Sichuan and Mudong of Chongqing from 2008 to 2010. The results showed that there were 6 age groups of our collected samples, and most individuals were 2—4 year-old accounting for about 95.7 percent of the total. According to the comparison of coefficient among linear function, exponential function, polynomial function and power function, and the relationship between body length (L) and scale radius (R) showed no significant difference between females and males, which could be expressed as L=51.28R+37.45 (r = 0.85, n = 397). And there was no significant difference between measured body length and back-calculated body length at each age group between females and males (t = 0.751, P > 0.05). Meanwhile, the relationship between body length (L) and body weight (W) showed no significant difference between females and males, and could be expressed as W= 8×10-6L3.099 (r = 0.97, n = 397). Von Bertalanffy growth function was Lt = 348.78 [1-e-0.18 (t +1.15)] and Wt = 603.17 [1-e-0.18 (t +1.15)]3.099. In addition, the age at the inflection point of body weight growth was 5.12 years old, when body length and body weight were 236.23 mm and 180.33 g, respectively. Besides, R. cylindricus was isometric growth and individual miniaturization. The exploitation of R. cylindricus in the upper of the Yangtze River was unreasonable, so we should take action to strictly ban catching in the future and strengthen scientific research on R. cylindricus to protect better.
2012, 36(2): 270-275.
DOI: 10.3724/SP.J.1035.2012.00270
Abstract：
The aims of the present experiment were to gain the motion regular patterns, the physical activity level, the rules of metabolic energy requirements and the lowest oxygen consumption of Schizothorax chongi (Cyprinida, Schizothoracinae). The flow rate was the main condition considered, and it was one of the major factors of the river environment. In the experiment, effects of flow rate on swimming behavior and energy consumption of Schizothorax chongi had been tested in a special sealed experimental device. The results suggested that the tail beat frequencies (TBF) of Schizothorax chongi increased with the swimming speed. But the tail beat amplitude decreased as the swimming speed increasing. According to the results of the oxygen consumption to the swimming speed, the oxygen consumption of Schizothorax chongi increased significantly as the swimming speed increased. The protocol of the critical swimming speed was carried out at 1BL interval for a set time of 30min. And the result showed that, at (26±1)℃, the relative critical swimming speed of Schizothorax chongi, body length of (10.60±0.54) cm, was (11.5±0.5) BL/s, and the absolute critical swimming speed was (110.28 ±2.02) cm/s. The relative critical swimming speed was higher than other carps, which was consisted with the habitat where the Schizothorax chongi lived, and the flow rate was 0.5—1.5 m/s. The result indicated that the capability of the swimming can be trained. The relationship between oxygen consumption rate and relative swimming speed at swimming speed of 1—7 BL/s was: AMR = 93.08e(0.326V)+314.33, R2= 0.994; the relationship between cost of transport (COT) and relative swimming speed was: COT=28e(-1.03V) +6.05, R2=0.998. While the swimming speed reached to 8 BL/s, the oxygen consumption rate was decreased to (978.78±189.38) mg O2/(kg·h) from the largest, (1245.57±90.97) mg O2/(kg·h), at 7 BL/s swimming speed. As the swimming speed increasing, 1—7 BL/s, metabolic rate increased obviously, but the cost of transport decreased, and the lowest consumption was (6.00±1.57)J/(kg·m), at 6 BL/s, about 0.68 m/s, which was considered as the maximum efficiency swimming speed. The study of the swimming behavior and oxygen consumption of Schizothorax chongi were to obtain the basic information for the physiology and ecology behaviors of this important species, and to find effective methods to protest it in the building of the fishes passage, and the optimal scheduling of cascaded hydropower stations.
The aims of the present experiment were to gain the motion regular patterns, the physical activity level, the rules of metabolic energy requirements and the lowest oxygen consumption of Schizothorax chongi (Cyprinida, Schizothoracinae). The flow rate was the main condition considered, and it was one of the major factors of the river environment. In the experiment, effects of flow rate on swimming behavior and energy consumption of Schizothorax chongi had been tested in a special sealed experimental device. The results suggested that the tail beat frequencies (TBF) of Schizothorax chongi increased with the swimming speed. But the tail beat amplitude decreased as the swimming speed increasing. According to the results of the oxygen consumption to the swimming speed, the oxygen consumption of Schizothorax chongi increased significantly as the swimming speed increased. The protocol of the critical swimming speed was carried out at 1BL interval for a set time of 30min. And the result showed that, at (26±1)℃, the relative critical swimming speed of Schizothorax chongi, body length of (10.60±0.54) cm, was (11.5±0.5) BL/s, and the absolute critical swimming speed was (110.28 ±2.02) cm/s. The relative critical swimming speed was higher than other carps, which was consisted with the habitat where the Schizothorax chongi lived, and the flow rate was 0.5—1.5 m/s. The result indicated that the capability of the swimming can be trained. The relationship between oxygen consumption rate and relative swimming speed at swimming speed of 1—7 BL/s was: AMR = 93.08e(0.326V)+314.33, R2= 0.994; the relationship between cost of transport (COT) and relative swimming speed was: COT=28e(-1.03V) +6.05, R2=0.998. While the swimming speed reached to 8 BL/s, the oxygen consumption rate was decreased to (978.78±189.38) mg O2/(kg·h) from the largest, (1245.57±90.97) mg O2/(kg·h), at 7 BL/s swimming speed. As the swimming speed increasing, 1—7 BL/s, metabolic rate increased obviously, but the cost of transport decreased, and the lowest consumption was (6.00±1.57)J/(kg·m), at 6 BL/s, about 0.68 m/s, which was considered as the maximum efficiency swimming speed. The study of the swimming behavior and oxygen consumption of Schizothorax chongi were to obtain the basic information for the physiology and ecology behaviors of this important species, and to find effective methods to protest it in the building of the fishes passage, and the optimal scheduling of cascaded hydropower stations.
Abstract：
Neosalanx taihuensis Chen is an important zooplanktivorous commercial fish, which was widely introduced into Chinese freshwaters. Transplantation of this species has induced decline and even extinction of native fish species in some waters. In this study, impacts of N. taihuensis transplantation on early growth and feeding of an indigenous zooplanktivorous fish Hemiculter leucisculus Basilewsky were investigated by comparing the juveniles of the latter in two reservoirs in the middle reach of the Yangtze River. Huangshi Reservoir (HSR) and Mengquan Reservoir (MQR) are geographically proximate and display similar nutrient regimes and native fish faunas. The major difference between the two water is that N. taihuensis has been transplanted in HSR but not in MQR. A total of 157 juvenile H. leucisculus was collected in late July and middle August in both reservoirs. The juveniles collected in late July aged from 14 to 23 days, and were similar in growth rate between the two waters. The juveniles collected in middle August aged from 20 to 49 days. Growth rate of juveniles in HSR was significantly smaller than those in MQR. Otolith growth trajectories showed that incremental width was not significantly different between the two reservoirs until the age of 25 days but narrower for juveniles in HSR than those in MQR after that. Diet analysis showed that food compositions of the juveniles younger than 25 days were similar between the two waters, composing mainly Rotifera, small-sized Cladocera and Cyclopoida. For juveniles older than 25 days, food compositions in HSR were similar to the younger juveniles, while the food compositions in MQR changed to large-sized Cladocera, insects, eggs and fish larvae. Spawning season of N. taihuensis is earlier than H. leucisculus in the middle reach of Yangtze River, and diet competition between the two species may occur after the later shifts from feeding on small-sized to large-sized zooplanktons. In HSR, N. taihuensis may induce the shortage of large-sized zooplanktons. As there was no enough large-sized zooplankton available to the juvenile H. leucisculus older than 25 days, they could only keep feeding on small-sized, which resulted in stunted growth of H. leucisculus juveniles older than 25 days compared to those in MQR.
Neosalanx taihuensis Chen is an important zooplanktivorous commercial fish, which was widely introduced into Chinese freshwaters. Transplantation of this species has induced decline and even extinction of native fish species in some waters. In this study, impacts of N. taihuensis transplantation on early growth and feeding of an indigenous zooplanktivorous fish Hemiculter leucisculus Basilewsky were investigated by comparing the juveniles of the latter in two reservoirs in the middle reach of the Yangtze River. Huangshi Reservoir (HSR) and Mengquan Reservoir (MQR) are geographically proximate and display similar nutrient regimes and native fish faunas. The major difference between the two water is that N. taihuensis has been transplanted in HSR but not in MQR. A total of 157 juvenile H. leucisculus was collected in late July and middle August in both reservoirs. The juveniles collected in late July aged from 14 to 23 days, and were similar in growth rate between the two waters. The juveniles collected in middle August aged from 20 to 49 days. Growth rate of juveniles in HSR was significantly smaller than those in MQR. Otolith growth trajectories showed that incremental width was not significantly different between the two reservoirs until the age of 25 days but narrower for juveniles in HSR than those in MQR after that. Diet analysis showed that food compositions of the juveniles younger than 25 days were similar between the two waters, composing mainly Rotifera, small-sized Cladocera and Cyclopoida. For juveniles older than 25 days, food compositions in HSR were similar to the younger juveniles, while the food compositions in MQR changed to large-sized Cladocera, insects, eggs and fish larvae. Spawning season of N. taihuensis is earlier than H. leucisculus in the middle reach of Yangtze River, and diet competition between the two species may occur after the later shifts from feeding on small-sized to large-sized zooplanktons. In HSR, N. taihuensis may induce the shortage of large-sized zooplanktons. As there was no enough large-sized zooplankton available to the juvenile H. leucisculus older than 25 days, they could only keep feeding on small-sized, which resulted in stunted growth of H. leucisculus juveniles older than 25 days compared to those in MQR.
2012, 36(2): 284-290.
DOI: 10.3724/SP.J.1035.2012.00284
Abstract：
Collichthys lucidus and Harpodon nehereus are small fishes which are common in the coastal waters of China. They are often fed to aquatic animals, and are also food for human. In this study, total volatile basic nitrogen( T-VBN)and nine biogenic amines (cadaverine, putrescine, histamine, tyramine, serotonin, spermidine, spermine, dopamine and octopamine) of C. lucidus and H. nehereus storage at 30℃ were examined in every 6h for 48h. The correlation analysis of the contents in T-VBN or biogenic amines with the storage time were also evaluated for these two species. The results showed that there were differences in the contents of biogenic amines and T-VBN in C. lucidus and H. nehereus. The content of T-VBN increased from 8.19 mg/100 g (0h) to 568.05 mg/100 g (48h) in C. lucidus, and from 13.16 mg/100 g (0h) to 361.34 mg/100 g (48h) in H. nehereus. The increase in the T-VBN content of C. lucidus was significantly higher than that in H. nehereus. The T-VBN contents of C. lucidus and H. nehereus exceeded the national edible standard of 30 mg/100 g after 10h and 12h respectively. Therefore these two species were not suitable to eat after 10h and 12h respectively. The highest contents of biogenic amines detected in these two species in order were cadaverine, putrescine, tyramine and histamine. The contents of these four biogenic amines increased significantly with the extension of storage time (PC. lucidus was significantly higher than that in H. nehereus (PP>0.05). Dopamine was not detected in these two species. The contents of T-VBN, cadaverine, putrescine, histamine and tyramine were found to correlate closely(P<0.01) with the storage time in these two species.
Collichthys lucidus and Harpodon nehereus are small fishes which are common in the coastal waters of China. They are often fed to aquatic animals, and are also food for human. In this study, total volatile basic nitrogen( T-VBN)and nine biogenic amines (cadaverine, putrescine, histamine, tyramine, serotonin, spermidine, spermine, dopamine and octopamine) of C. lucidus and H. nehereus storage at 30℃ were examined in every 6h for 48h. The correlation analysis of the contents in T-VBN or biogenic amines with the storage time were also evaluated for these two species. The results showed that there were differences in the contents of biogenic amines and T-VBN in C. lucidus and H. nehereus. The content of T-VBN increased from 8.19 mg/100 g (0h) to 568.05 mg/100 g (48h) in C. lucidus, and from 13.16 mg/100 g (0h) to 361.34 mg/100 g (48h) in H. nehereus. The increase in the T-VBN content of C. lucidus was significantly higher than that in H. nehereus. The T-VBN contents of C. lucidus and H. nehereus exceeded the national edible standard of 30 mg/100 g after 10h and 12h respectively. Therefore these two species were not suitable to eat after 10h and 12h respectively. The highest contents of biogenic amines detected in these two species in order were cadaverine, putrescine, tyramine and histamine. The contents of these four biogenic amines increased significantly with the extension of storage time (PC. lucidus was significantly higher than that in H. nehereus (PP>0.05). Dopamine was not detected in these two species. The contents of T-VBN, cadaverine, putrescine, histamine and tyramine were found to correlate closely(P<0.01) with the storage time in these two species.
2012, 36(2): 291-298.
DOI: 10.3724/SP.J.1035.2011.002911
Abstract：
Epiphytic algae on three stream macroalgae (Chara vulgaris, Cladophora fracta and Batrachospermum arcuatum) were collected from two sites in Xin'an Spring, North China, during July 2004 to April 2005 (one sampling per season). The species composition, distribution and effect of environmental factors on the epiphytic algae were studied. Several environmental factors were monitored at the same time. The species number of epiphytic algae on the three stream macroalgae was different because the habitat structure had pervasive effects on community composition and diversity. The epiphytic algae on Chara vulgaris resulted in 49 species, 37 species on Cladophora fracta and only 6 species on Batrachospermum arcuatum, respectively. The predominant species of epiphytic algae on the three stream macroalgae belongs to Bacillariophyta. In terms of the seasonality, there was an obvious seasonal trend in species number of epiphytic algae: spring > autumn > summer > winter. The results also indicate that there were some environmental factors influenced the epiphytic algae in different extents. The key factors were current velocity, maximum depth, and specific conductance.
Epiphytic algae on three stream macroalgae (Chara vulgaris, Cladophora fracta and Batrachospermum arcuatum) were collected from two sites in Xin'an Spring, North China, during July 2004 to April 2005 (one sampling per season). The species composition, distribution and effect of environmental factors on the epiphytic algae were studied. Several environmental factors were monitored at the same time. The species number of epiphytic algae on the three stream macroalgae was different because the habitat structure had pervasive effects on community composition and diversity. The epiphytic algae on Chara vulgaris resulted in 49 species, 37 species on Cladophora fracta and only 6 species on Batrachospermum arcuatum, respectively. The predominant species of epiphytic algae on the three stream macroalgae belongs to Bacillariophyta. In terms of the seasonality, there was an obvious seasonal trend in species number of epiphytic algae: spring > autumn > summer > winter. The results also indicate that there were some environmental factors influenced the epiphytic algae in different extents. The key factors were current velocity, maximum depth, and specific conductance.
2012, 36(2): 299-306.
DOI: 10.3724/SP.J.1035.2012.00299
Abstract：
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants derived from incomplete combustion of carbon. As a pollutant, they are of concern because some compounds have been identified as carcinogenic, mutagenic and teratogenic. Benzopyrene (B[a]P) is a five-ring polycyclic aromatic hydrocarbon whose metabolites are mutagenic and highly carcinogenic. It is listed as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC). B[a]P is the most studied high molecular mass PAH and usually used as the model of PAHs. In China, environmental PAHs concentrations have been increasing day after day, particularly in aquatic environment. Therefore, more and more researchers pay attention to the toxic effects of PAHs/B[a]P on organisms and human health. Biomarkers are important tools for measuring of exposure to and effects of stressors that may arise at the molecular, cellular, physiological or behavioral level of an individual organism. Recently, they have been widely used to assess the effects of pollutants on aquatic animals. In present study, the effects of B[a]P on activities of detoxification metabolism parameters in gills and digestive glands of scallop Chlamys farreri were studied. At first, the clams were exposed to different concentrations of B[a]P (0.05, 0.5, 5 and 10 μg/L) for 15 days, and then they were cultured in normal seawater without B[a]P for 30 days. At last, the clams were treated with B[a]P for 15 days again. The experiment lasted for 60 days and the gills and digestive glands of the clams in control and different treatments were sampled at 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 and 60 day respectively. The activities of aryl hydrocarbon hydroxylase (AHH) and Glutathione S-transferase (GST), the content of Glutathione (GSH), DNA damaged and DNA-protein crosslinks (DPC) were tested by Spectrophotometry. The results indicated that the activity of AHH was significantly induced (Pa]P, while GST activity and GSH content decreased with the increase of B[a]P concentration and the prolong of experimental period. DNA damage and DNA-protein crosslinks were increased with the increase of concentration of B[a]P. All parameters were returned to control level during the clearance stage except the 5 and 10 μg/L groups DPC which were still significant higher than control. When the clams were treated with different concentration of B[a]P again, the change trends of all the parameters were similar to the first stage of B[a]P treatment. The correlation analysis showed that there was a good relativity between the indexes and the concentration of B[a]P. It supposed that all the parameters in the study can be the potential biomarkers for the PAHs contamination assessment. In addition, AHH, GST and DPC value were much more suitable for biological monitoring as the biomarkers because of their stability. They can form the combined biomarkers and used for pollution monitoring sensitively and effectively. In a word, the resulting data in this study may provide basic information of PAHs pollution assessment and the useful monitoring strategy of biomarkers for related departments. What is more, the scientific data must be useful for the assessment of food security in the ocean and estimate the hazard of pollutants to the aquatic products.
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants derived from incomplete combustion of carbon. As a pollutant, they are of concern because some compounds have been identified as carcinogenic, mutagenic and teratogenic. Benzopyrene (B[a]P) is a five-ring polycyclic aromatic hydrocarbon whose metabolites are mutagenic and highly carcinogenic. It is listed as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC). B[a]P is the most studied high molecular mass PAH and usually used as the model of PAHs. In China, environmental PAHs concentrations have been increasing day after day, particularly in aquatic environment. Therefore, more and more researchers pay attention to the toxic effects of PAHs/B[a]P on organisms and human health. Biomarkers are important tools for measuring of exposure to and effects of stressors that may arise at the molecular, cellular, physiological or behavioral level of an individual organism. Recently, they have been widely used to assess the effects of pollutants on aquatic animals. In present study, the effects of B[a]P on activities of detoxification metabolism parameters in gills and digestive glands of scallop Chlamys farreri were studied. At first, the clams were exposed to different concentrations of B[a]P (0.05, 0.5, 5 and 10 μg/L) for 15 days, and then they were cultured in normal seawater without B[a]P for 30 days. At last, the clams were treated with B[a]P for 15 days again. The experiment lasted for 60 days and the gills and digestive glands of the clams in control and different treatments were sampled at 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 and 60 day respectively. The activities of aryl hydrocarbon hydroxylase (AHH) and Glutathione S-transferase (GST), the content of Glutathione (GSH), DNA damaged and DNA-protein crosslinks (DPC) were tested by Spectrophotometry. The results indicated that the activity of AHH was significantly induced (Pa]P, while GST activity and GSH content decreased with the increase of B[a]P concentration and the prolong of experimental period. DNA damage and DNA-protein crosslinks were increased with the increase of concentration of B[a]P. All parameters were returned to control level during the clearance stage except the 5 and 10 μg/L groups DPC which were still significant higher than control. When the clams were treated with different concentration of B[a]P again, the change trends of all the parameters were similar to the first stage of B[a]P treatment. The correlation analysis showed that there was a good relativity between the indexes and the concentration of B[a]P. It supposed that all the parameters in the study can be the potential biomarkers for the PAHs contamination assessment. In addition, AHH, GST and DPC value were much more suitable for biological monitoring as the biomarkers because of their stability. They can form the combined biomarkers and used for pollution monitoring sensitively and effectively. In a word, the resulting data in this study may provide basic information of PAHs pollution assessment and the useful monitoring strategy of biomarkers for related departments. What is more, the scientific data must be useful for the assessment of food security in the ocean and estimate the hazard of pollutants to the aquatic products.
2012, 36(2): 307-315.
DOI: 10.3724/SP.J.1035.2012.00307
Abstract：
Heavy metal pollution of water bodies has become an increasingly serious environmental problem. Understand the principles of heavy metal contamination and heavy metals in water treatment have become a topic that must be addressed. Heavy metals can cause serious health hazards to animals and humans through the food chain due to the refractory, easy accumulation, toxicity and other characteristics. Therefore, much attention has been devoted to the studies on the mechanisms of heavy metal tolerance in plants and how to improve heavy metal tolerance of plants. Although antioxidative reactions of plants subjected to Pb2+ have been studied by several authors, there are few reports on the research of callus response to heavy metals. In view of this, callus of Alternanthera philoxeroides was cultured to overcome the uncontrollability of light, temperature, moisture and plant growth and development in the natural state, so that the experimental data is more repeated and scientific. Callus of Alternanthera philoxeroides stems was cultured in 1/2 MS medium including 6-BA (3.0 mg/L) and NAA (0.2 mg/L) after the disinfection of 70% ethanol 30s, 5% sodium hypochlorite 10min and 0.1% mercuric chloride 10min, was used as experimental material, and Pb2+ was selected as the stress factor. The toxic effects of Pb gradient concentrations (0, 0.2, 0.4, 0.8 and 1.6 mmol/L) on the accumulation, subcellular distribution, ultrastructural localization and mineral elements were studied. The results indicated that, with the increasing of Pb concentration, (1) Alternanthera philoxeroides callus was able to accumulate lead, the bioconcentration factor was 2341-2681; (2) Subcellular fraction analysis revealed that the contents of Pb increased gradually in cell wall, organelles and soluble fraction, but the distribution ratio was obviously unequal, and the Pb levels occurred in different parts of callus cell with the following sequence cell wall>organelles>soluble fraction. The toxic symptoms of callus showed an evident correlation between dose and effect and the ultrastructural damage was closely related to the distribution of Pb; (3) Ultrastructural localization observation showed that Pb mainly appeared in cell wall, and was also found in cell membrane structure and cell matrix; (4) The effects of lead on mineral elements in three subcellular fractions were different, of which the absorption of macroelements P, K, Mg and microelements Na, Zn, Mn were inhibited; the content of Ca increased at first and then decreased in cell wall, decreased gradually in organelles, increased gradually in soluble fraction; Fe and B increased at first and then decreased in subcellular fractions; the content of Cu in cell wall and organelles displayed with increase trends, increased at first and then decreased in soluble fraction; the content of Si in cell wall decreased gradually, increased at first and then decreased in organelles, while it was not able to be measured in soluble fraction. It could clearly be seen that the ion equilibrium in subcellular fractions was disrupted under Pb stress, resulting in disorder of physiological metabolism. All of these were major performance of lead on callus of Alternanthera philoxeroides.
Heavy metal pollution of water bodies has become an increasingly serious environmental problem. Understand the principles of heavy metal contamination and heavy metals in water treatment have become a topic that must be addressed. Heavy metals can cause serious health hazards to animals and humans through the food chain due to the refractory, easy accumulation, toxicity and other characteristics. Therefore, much attention has been devoted to the studies on the mechanisms of heavy metal tolerance in plants and how to improve heavy metal tolerance of plants. Although antioxidative reactions of plants subjected to Pb2+ have been studied by several authors, there are few reports on the research of callus response to heavy metals. In view of this, callus of Alternanthera philoxeroides was cultured to overcome the uncontrollability of light, temperature, moisture and plant growth and development in the natural state, so that the experimental data is more repeated and scientific. Callus of Alternanthera philoxeroides stems was cultured in 1/2 MS medium including 6-BA (3.0 mg/L) and NAA (0.2 mg/L) after the disinfection of 70% ethanol 30s, 5% sodium hypochlorite 10min and 0.1% mercuric chloride 10min, was used as experimental material, and Pb2+ was selected as the stress factor. The toxic effects of Pb gradient concentrations (0, 0.2, 0.4, 0.8 and 1.6 mmol/L) on the accumulation, subcellular distribution, ultrastructural localization and mineral elements were studied. The results indicated that, with the increasing of Pb concentration, (1) Alternanthera philoxeroides callus was able to accumulate lead, the bioconcentration factor was 2341-2681; (2) Subcellular fraction analysis revealed that the contents of Pb increased gradually in cell wall, organelles and soluble fraction, but the distribution ratio was obviously unequal, and the Pb levels occurred in different parts of callus cell with the following sequence cell wall>organelles>soluble fraction. The toxic symptoms of callus showed an evident correlation between dose and effect and the ultrastructural damage was closely related to the distribution of Pb; (3) Ultrastructural localization observation showed that Pb mainly appeared in cell wall, and was also found in cell membrane structure and cell matrix; (4) The effects of lead on mineral elements in three subcellular fractions were different, of which the absorption of macroelements P, K, Mg and microelements Na, Zn, Mn were inhibited; the content of Ca increased at first and then decreased in cell wall, decreased gradually in organelles, increased gradually in soluble fraction; Fe and B increased at first and then decreased in subcellular fractions; the content of Cu in cell wall and organelles displayed with increase trends, increased at first and then decreased in soluble fraction; the content of Si in cell wall decreased gradually, increased at first and then decreased in organelles, while it was not able to be measured in soluble fraction. It could clearly be seen that the ion equilibrium in subcellular fractions was disrupted under Pb stress, resulting in disorder of physiological metabolism. All of these were major performance of lead on callus of Alternanthera philoxeroides.
2012, 36(2): 316-322.
DOI: 10.3724/SP.J.1035.2012.00316
Abstract：
For some aquatic macrophytes, stem fragment formed by disturbance plays a key role in the dispersal and establishment of the species. Previous studies have been focused on the regeneration abilities of sterm fragments of a range of aquatic species. However, the information on regeneration ability of fragments between narrow endemic and its congeneric widespread species is lacking. Our study examined the combined effects of fragment length and fragment location on regeneration performances of narrow endemic (Myriophyllum oguraense Miki subsp. yangtzense Wang) and widespread (M. spicatum L.) species, two submerged macrophytes in shallow lakes of the lower Yangtze River basin of China, by an outdoor experiment. Stem fragments from one genotype of population were planted separately in plastic pots by three fragment lengths (5 cm, 10 cm and 15 cm) and three fragment locations (apex, midstem and bottom). The objective of this study were to determine (1) whether fragment length and location correlate with the growth and regeneration abilities of the studied species, and (2) whether the growth and regeneration abilities of fragments differ between the narrow endemic and its congenetic widespread species. The results showed that total plant biomass, total branch biomass and branch number increased significantly with increasing fragment length between all treatments at the fragment level for both species. Total plant biomass, total branch biomass and branch number were greatly different between three length treatments, which were the greatest for fragments of 15 cm in length compared with the other two fragment length treatments. Additionally, the growth and regeneration performance of the studied species were significantly affected by fragment location. There were remarkable differences between the growth of sterm fragments with apices and those without apices. Plant from apical fragments had the largest plant biomass, and midstem fragments regenerated the largest branch biomass, the most lateral branches and the longest branches. Fragments without apices showed significant greater branch number and branch biomass compared with the ones with apices, except that those traits of bottom fragments were intermediate. Meanwhile, plant biomass, branch biomass, branch number, average branch length and branch position inserted at the stem were found to be significantly different between the species studied. For M. oguraense Miki subsp. yangtzense Wang, fragments regenerated larger branch biomass, more lateral branches and longer branches, while fragments produced larger total plant biomass for M. spicatum L., indicating that different regenerative strategies of fragments occurred between the two species. Moreover, apical fragment of M. spicatum L. regenerated lateral branches at the bottom of the stem, while all fragments of M. oguraense Miki subsp. yangtzense Wang produced lateral branches at the top of stem. The present data confirmed the previous conclusion that larger fragments had higher regeneration abilities than smaller fragments and the regeneration potential of fragments with an apical tip was greater than fragments without an apical tip. Our study implied that the regrowth patterns differ between the studied species. M. spicatum L. was prone to increase investment in plant biomass while M. oguraense Miki subsp. yangtzense Wang was prone to invest more to reproduction of lateral branches. This suggested that regeneration performances of fragments of the studied macrophytes were species-specific and fragment trait-dependent, and the results might provide reference for biodiversity conservation and wetland vegetation management.
For some aquatic macrophytes, stem fragment formed by disturbance plays a key role in the dispersal and establishment of the species. Previous studies have been focused on the regeneration abilities of sterm fragments of a range of aquatic species. However, the information on regeneration ability of fragments between narrow endemic and its congeneric widespread species is lacking. Our study examined the combined effects of fragment length and fragment location on regeneration performances of narrow endemic (Myriophyllum oguraense Miki subsp. yangtzense Wang) and widespread (M. spicatum L.) species, two submerged macrophytes in shallow lakes of the lower Yangtze River basin of China, by an outdoor experiment. Stem fragments from one genotype of population were planted separately in plastic pots by three fragment lengths (5 cm, 10 cm and 15 cm) and three fragment locations (apex, midstem and bottom). The objective of this study were to determine (1) whether fragment length and location correlate with the growth and regeneration abilities of the studied species, and (2) whether the growth and regeneration abilities of fragments differ between the narrow endemic and its congenetic widespread species. The results showed that total plant biomass, total branch biomass and branch number increased significantly with increasing fragment length between all treatments at the fragment level for both species. Total plant biomass, total branch biomass and branch number were greatly different between three length treatments, which were the greatest for fragments of 15 cm in length compared with the other two fragment length treatments. Additionally, the growth and regeneration performance of the studied species were significantly affected by fragment location. There were remarkable differences between the growth of sterm fragments with apices and those without apices. Plant from apical fragments had the largest plant biomass, and midstem fragments regenerated the largest branch biomass, the most lateral branches and the longest branches. Fragments without apices showed significant greater branch number and branch biomass compared with the ones with apices, except that those traits of bottom fragments were intermediate. Meanwhile, plant biomass, branch biomass, branch number, average branch length and branch position inserted at the stem were found to be significantly different between the species studied. For M. oguraense Miki subsp. yangtzense Wang, fragments regenerated larger branch biomass, more lateral branches and longer branches, while fragments produced larger total plant biomass for M. spicatum L., indicating that different regenerative strategies of fragments occurred between the two species. Moreover, apical fragment of M. spicatum L. regenerated lateral branches at the bottom of the stem, while all fragments of M. oguraense Miki subsp. yangtzense Wang produced lateral branches at the top of stem. The present data confirmed the previous conclusion that larger fragments had higher regeneration abilities than smaller fragments and the regeneration potential of fragments with an apical tip was greater than fragments without an apical tip. Our study implied that the regrowth patterns differ between the studied species. M. spicatum L. was prone to increase investment in plant biomass while M. oguraense Miki subsp. yangtzense Wang was prone to invest more to reproduction of lateral branches. This suggested that regeneration performances of fragments of the studied macrophytes were species-specific and fragment trait-dependent, and the results might provide reference for biodiversity conservation and wetland vegetation management.
2012, 36(2): 323-328.
DOI: 10.3724/SP.J.1035.2012.00323
Abstract：
Aphanizomenon has been widely reported in many freshwater bodies, and was regarded as one of important bloom-forming cyanobacterial strains. Owing to its effect, directly or indirectly, to animals and human beings, great attention has been focused on the formation mechanism by researchers in areas such as, aquatic ecology, phycology, environmental science, and so on. In China, Aphanizomenon bloom has resulted in many environmental and ecological problems. As already illustrated, bloom-forming cyanobacteria has developed some sound ecological strategies to form water bloom with a series of special physiological mechanisms and adaptation characters during evolution. However, the physiological mechanisms and adaptation characters in Aphanizomenon remain largely unknown. Previous study in our laboratory had shown that three types of Aphanizomenon, A. flos-aquae, A. gracile and A. issatschenkoi, were the most common strains in Chinese freshwater bodies. Due to the limitation of samples and knowledge, however, the physiological characters were not compared in the three-type strains so far. Therefore, in order to further explore their knowledge and investigate the bloom-forming mechanism in Aphanizomenon, in the present study, their morphological and physiological characteristics, including the ratio of length and width in vegetative cell, heterocyst and akinete, growth rate, pigment composition, photosynthetic O2 evolution, and the electron transport rate (ETR), were compared in A. flos-aquae, A. gracile and A. issatschenkoi. The results indicated that some morphological differences were found in the frequency distributions for length/width ratios of vegetative cells, heterocyst, and akinetes. Among them, the most significant difference was found in the akinetes, suggesting that the length/ width ratios of akinetes could be regarded as a taxonomic unit in the genus Aphanizomenon. Moreover, physiological differences were also showed in three types of Aphanizomenon. Compared with the strains of A. flos-aquae and A. issatschenkoi, the strains of A. gracile displayed higher PC contents. However, the strains of A. gracile showed significantly lower chlorophyll α, carotenoid contents, maximum photosynthesis (Pm), apparent photosynthetic efficiency (α), and maximal electron transport rates (ETRmax) in comparison with the other strains of Aphanizomenon. It suggested that the strain of A. gracile showed lower competitive abilities in photosynthesis when compared with the strains of A. flos-aquae and A. issatschenkoi. In addition, similar physiological features, such as the value of Pm and ETRmax, pigment contents and specific growth rate (μ), were found in A. flos-aquae and A. issatschenkoi. These data suggested that the three morphological strains of Aphanizomenon could be divided into two types based on their physiological characterizations, namely, A. gracile-type and A. flos-aquae/issatschenkoi-type, and indicated that the strains of A. issatschenkoi might be potential bloom-formation strains as the same as the strains of A. flos-aquae and must be played a considerate attention due to its toxicity.
Aphanizomenon has been widely reported in many freshwater bodies, and was regarded as one of important bloom-forming cyanobacterial strains. Owing to its effect, directly or indirectly, to animals and human beings, great attention has been focused on the formation mechanism by researchers in areas such as, aquatic ecology, phycology, environmental science, and so on. In China, Aphanizomenon bloom has resulted in many environmental and ecological problems. As already illustrated, bloom-forming cyanobacteria has developed some sound ecological strategies to form water bloom with a series of special physiological mechanisms and adaptation characters during evolution. However, the physiological mechanisms and adaptation characters in Aphanizomenon remain largely unknown. Previous study in our laboratory had shown that three types of Aphanizomenon, A. flos-aquae, A. gracile and A. issatschenkoi, were the most common strains in Chinese freshwater bodies. Due to the limitation of samples and knowledge, however, the physiological characters were not compared in the three-type strains so far. Therefore, in order to further explore their knowledge and investigate the bloom-forming mechanism in Aphanizomenon, in the present study, their morphological and physiological characteristics, including the ratio of length and width in vegetative cell, heterocyst and akinete, growth rate, pigment composition, photosynthetic O2 evolution, and the electron transport rate (ETR), were compared in A. flos-aquae, A. gracile and A. issatschenkoi. The results indicated that some morphological differences were found in the frequency distributions for length/width ratios of vegetative cells, heterocyst, and akinetes. Among them, the most significant difference was found in the akinetes, suggesting that the length/ width ratios of akinetes could be regarded as a taxonomic unit in the genus Aphanizomenon. Moreover, physiological differences were also showed in three types of Aphanizomenon. Compared with the strains of A. flos-aquae and A. issatschenkoi, the strains of A. gracile displayed higher PC contents. However, the strains of A. gracile showed significantly lower chlorophyll α, carotenoid contents, maximum photosynthesis (Pm), apparent photosynthetic efficiency (α), and maximal electron transport rates (ETRmax) in comparison with the other strains of Aphanizomenon. It suggested that the strain of A. gracile showed lower competitive abilities in photosynthesis when compared with the strains of A. flos-aquae and A. issatschenkoi. In addition, similar physiological features, such as the value of Pm and ETRmax, pigment contents and specific growth rate (μ), were found in A. flos-aquae and A. issatschenkoi. These data suggested that the three morphological strains of Aphanizomenon could be divided into two types based on their physiological characterizations, namely, A. gracile-type and A. flos-aquae/issatschenkoi-type, and indicated that the strains of A. issatschenkoi might be potential bloom-formation strains as the same as the strains of A. flos-aquae and must be played a considerate attention due to its toxicity.
2012, 36(2): 329-338.
DOI: 10.3724/SP.J.1035.2012.00329
Abstract：
Salt stress is one of important ecological factors influencing survival of desert soil algae. Palmellococcus Chod. is a kind of green algae widely distribute in biological soil crusts and is able to accumulate red pigment (astaxanthin) and oil drops, and the algae has displayed especial physiological nature and potential value of application. Currently, studies on physiology, cellular structures and pigment accumulations of Palmellococcus sp. were relatively scarce. In this study, Palmellococcus sp., isolated from desert algal crusts, was selected for experiment material. Physiological effects of salt stress on the algal cells were investigated by measuring biomass (expressed as chlorophyll a), PS activity Ⅱ (Fv/Fm), intracellular production of water-soluble proteins and saccharides, MDA contents as well as the activities of SOD and CAT. The results showed that salt stress resulted in an obvious decrease in biomass and PSⅡ activity of the treated cells compared to the control cells. It also indicated that intracellular production of water-soluble saccharide and water-soluble proteins were all comparatively greater in the treatment cells than the control cells. Moreover, salt stress had a significantly deleterious effect on membrane lipid superoxide as assessed by measurement of MDA content, and SOD and CAT activities also presented obvious increases as compared to the control. At the same time, it showed from this study that cellular structures and morphological characteristics of Palmellococcus sp. were found to keep intact and clear in the control condition, and there was plentiful lipid body accumulation at growth anaphase of the control culture. However, gradual destruction property in cellular structures were observed from Palmellococcus sp. subjected to salt stress, and synchronously starch and lipid body accumulation were also detected in the treated cells. Furthermore, unintelligible cellular structures and disappearance of cellular organs were observed from Palmellococcus sp. under salt treatment, and plasmolysis and vacuolization were appeared in the treated algal cells. The research results maybe provided us some significative findings for better understanding physiological adaptation, morphological changes and pigment accumulation of Palmellococcus sp. when subjected to salt stress environment, and simultaneously provided us many experimental data for further researches and applications about the green algae.
Salt stress is one of important ecological factors influencing survival of desert soil algae. Palmellococcus Chod. is a kind of green algae widely distribute in biological soil crusts and is able to accumulate red pigment (astaxanthin) and oil drops, and the algae has displayed especial physiological nature and potential value of application. Currently, studies on physiology, cellular structures and pigment accumulations of Palmellococcus sp. were relatively scarce. In this study, Palmellococcus sp., isolated from desert algal crusts, was selected for experiment material. Physiological effects of salt stress on the algal cells were investigated by measuring biomass (expressed as chlorophyll a), PS activity Ⅱ (Fv/Fm), intracellular production of water-soluble proteins and saccharides, MDA contents as well as the activities of SOD and CAT. The results showed that salt stress resulted in an obvious decrease in biomass and PSⅡ activity of the treated cells compared to the control cells. It also indicated that intracellular production of water-soluble saccharide and water-soluble proteins were all comparatively greater in the treatment cells than the control cells. Moreover, salt stress had a significantly deleterious effect on membrane lipid superoxide as assessed by measurement of MDA content, and SOD and CAT activities also presented obvious increases as compared to the control. At the same time, it showed from this study that cellular structures and morphological characteristics of Palmellococcus sp. were found to keep intact and clear in the control condition, and there was plentiful lipid body accumulation at growth anaphase of the control culture. However, gradual destruction property in cellular structures were observed from Palmellococcus sp. subjected to salt stress, and synchronously starch and lipid body accumulation were also detected in the treated cells. Furthermore, unintelligible cellular structures and disappearance of cellular organs were observed from Palmellococcus sp. under salt treatment, and plasmolysis and vacuolization were appeared in the treated algal cells. The research results maybe provided us some significative findings for better understanding physiological adaptation, morphological changes and pigment accumulation of Palmellococcus sp. when subjected to salt stress environment, and simultaneously provided us many experimental data for further researches and applications about the green algae.
2012, 36(2): 339-343.
DOI: 10.3724/SP.J.1035.2012.00339
Abstract：
It is the first report on Cyanophage isolated from Lake Taihu and infected Microcystis aernginosa (M. aernginosa). Water samples were collected from Lake Taihu during bloom season. The water sample was filtered through 0.22 μm polycarbonate membranes and concentrated by tangential flow fitration system, and then was inoculated into exponentially growing cultures of M. aernginosa strains. A further research was done for the algae with obvious infection. The results showed that M. aernginosa 905 was lysed. The lysate was purified through the method of CsCl density gradient centrifugation and one-step growth curve for the cyanophage was also studied. When MOI was 10-5, the latent phase of cyanophage infecting M. aernginosa was 2 hours, the rise phase was 4-6 hours and stabilization was 6-12 hours. The burst size was 4 pfu/cell. The virion with an icosahedral head (nearly 50 nm in diameter) and a short tail was observed under the transmission electron microscopy. The cyanophage had not only the specificity of species but also the specificity of strains. It could only infect M. aernginosa 905. In addition, the infection activity was lost when the cyanophage was stored at -20 an℃ d -80℃ without cryoprotectants, but the infection activity maintained over 50 days at 4℃. The above findings provide a potential method for biological control of algae bloom by cyanophage.
It is the first report on Cyanophage isolated from Lake Taihu and infected Microcystis aernginosa (M. aernginosa). Water samples were collected from Lake Taihu during bloom season. The water sample was filtered through 0.22 μm polycarbonate membranes and concentrated by tangential flow fitration system, and then was inoculated into exponentially growing cultures of M. aernginosa strains. A further research was done for the algae with obvious infection. The results showed that M. aernginosa 905 was lysed. The lysate was purified through the method of CsCl density gradient centrifugation and one-step growth curve for the cyanophage was also studied. When MOI was 10-5, the latent phase of cyanophage infecting M. aernginosa was 2 hours, the rise phase was 4-6 hours and stabilization was 6-12 hours. The burst size was 4 pfu/cell. The virion with an icosahedral head (nearly 50 nm in diameter) and a short tail was observed under the transmission electron microscopy. The cyanophage had not only the specificity of species but also the specificity of strains. It could only infect M. aernginosa 905. In addition, the infection activity was lost when the cyanophage was stored at -20 an℃ d -80℃ without cryoprotectants, but the infection activity maintained over 50 days at 4℃. The above findings provide a potential method for biological control of algae bloom by cyanophage.
Abstract：
Microcystis aeruginosa Kütz is a freshwater bloom-forming cyanobacterium that is found all over the world. Owing to their adverse effects on water quality and human health, these blooms in water of reservoirs and recreational water systems are a cause of great concern, M. aeruginosa became to a popular research object. Previous studies have revealed significant differences between the physiological parameters and stress responses of individual cells in lab and wild type colonial of Microcystis in fields. Therefore, to avoid the loss of natural characteristics, an efficient technology or method would have to be used for preservation of M. aeruginosa. Cryopreservation is a useful method to preserve cells and organs for a long time in lab. It was thus used on M. aeruginosa in order to keep the physiological characteristics stable at long-term studies. In the present study, cryopreservation of three strains M. aeruginosa (PCC7806, FACHB-905 and FACHB-942) was accomplished successfully. Combination of three penetrating cryoprotective additives (CPA) (methanol, dimethylsulphoxide (Me2SO), glycerol) and non-penetrating polyvinylpyrrolidone (PVP) could improve viability almost 20% than only using the same penetrating CPA. The optimal protocol of cryopreservation was screened from CPAs above and four concentrations of each, two cooling rates (-1 /min ℃ n and -0.5℃/min), and the first-step temperature degreed (-30℃, -40℃ and -80℃) of traditional two step methods. In addition, cell viability was determined by performing flow cytometry with fluorescein diacetate (FDA). The results showed that an optimal cooling protocol was at cooling rate of 0.5℃/min to -40℃ and combination of penetrating CPA (Me2SO, 5%) and non-penetrating CPA (PVP, 30%). The ratios of viable cells in the FACHB-942, PCC-7806 and FACHB-905 were approximately (62.72 ± 0.15)%, (66.3 ± 0.65)%, and (71.69 ± 0.39)%, respectively. However, the ratios of viable cells in these strains were all only about 45%. At this protocol of cryopreservation, physiological parameters of three strains M. aeruginosa such as PSII, the cells pigments and specific growth rates were analyzed before preservation and after thaw, results about the comparison showed that M. aeruginosa could keep its physiological characteristics stable.
Microcystis aeruginosa Kütz is a freshwater bloom-forming cyanobacterium that is found all over the world. Owing to their adverse effects on water quality and human health, these blooms in water of reservoirs and recreational water systems are a cause of great concern, M. aeruginosa became to a popular research object. Previous studies have revealed significant differences between the physiological parameters and stress responses of individual cells in lab and wild type colonial of Microcystis in fields. Therefore, to avoid the loss of natural characteristics, an efficient technology or method would have to be used for preservation of M. aeruginosa. Cryopreservation is a useful method to preserve cells and organs for a long time in lab. It was thus used on M. aeruginosa in order to keep the physiological characteristics stable at long-term studies. In the present study, cryopreservation of three strains M. aeruginosa (PCC7806, FACHB-905 and FACHB-942) was accomplished successfully. Combination of three penetrating cryoprotective additives (CPA) (methanol, dimethylsulphoxide (Me2SO), glycerol) and non-penetrating polyvinylpyrrolidone (PVP) could improve viability almost 20% than only using the same penetrating CPA. The optimal protocol of cryopreservation was screened from CPAs above and four concentrations of each, two cooling rates (-1 /min ℃ n and -0.5℃/min), and the first-step temperature degreed (-30℃, -40℃ and -80℃) of traditional two step methods. In addition, cell viability was determined by performing flow cytometry with fluorescein diacetate (FDA). The results showed that an optimal cooling protocol was at cooling rate of 0.5℃/min to -40℃ and combination of penetrating CPA (Me2SO, 5%) and non-penetrating CPA (PVP, 30%). The ratios of viable cells in the FACHB-942, PCC-7806 and FACHB-905 were approximately (62.72 ± 0.15)%, (66.3 ± 0.65)%, and (71.69 ± 0.39)%, respectively. However, the ratios of viable cells in these strains were all only about 45%. At this protocol of cryopreservation, physiological parameters of three strains M. aeruginosa such as PSII, the cells pigments and specific growth rates were analyzed before preservation and after thaw, results about the comparison showed that M. aeruginosa could keep its physiological characteristics stable.
2012, 36(2): 352-360.
DOI: 10.3724/SP.J.1035.2012.00352
2012, 36(2): 361-364.
DOI: 10.3724/SP.J.1035.2012.00361
2012, 36(2): 365-367.
DOI: 10.3724/SP.J.1035.2012.00365
