In May of 2007,the second generation selected （SS） and control （SC） groups of pearl oyster Pinctada martensii were established by selecting 10% breeders with the largest and mean shell length,respectively,from the...In May of 2007,the second generation selected （SS） and control （SC） groups of pearl oyster Pinctada martensii were established by selecting 10% breeders with the largest and mean shell length,respectively,from the first generation selected group.Growth performance of the SS and SC groups were compared on the basis of measurement data at Days 8,18,60,95,195 and 365.On Day 365,100 individuals （60.0–75.0 mm at shell length） were sampled from each group and then subjected to the experiment where physiological parameters such as filtrate rate,oxygen consumption and ammonia excretion were measured at 15,20,25 and 30°C.The results show that the SS group had significantly larger mean shell length and shell height than the SC group at Days 8,18,60,95,195 and 365 （P 0.05）.The genetic gains at different ages varied from 6.0% to 17.0% for shell length and 5.7% to 14.6% for shell height,respectively.At 15,20,25 and 30 ° C,the SS groups had significantly larger filtrate rate than the SC group （P 0.05）.At 15 and 25 °C,the differences in oxygen consumption rate between the SS and SC groups were not significant （P 0.05）.At 20 and 30 °C,however,the oxygen consumption rate of the SS group was significantly larger than the SC group （P 0.05）.At 15,20,25 and 30 °C,there were no significant differences in ammonia excretion rate between the SS and SC groups （P 0.05）.The present results indicate that there existed considerable genetic variability in the base population and a further selection could be likely fruitful.Mass selection for faster growth might produce animals that had higher intake of metabolizable energy by virtue of faster filtrating behavior.展开更多
Sequence variation of the first internal transcribed spacer of ribosomal DNA （ ITS - 1 ） was examined and its application to the study of genetic variation was explored in four populations of farter＇ s scallop Chla...Sequence variation of the first internal transcribed spacer of ribosomal DNA （ ITS - 1 ） was examined and its application to the study of genetic variation was explored in four populations of farter＇ s scallop Chlamys farreri. ITS - 1 fragments, with a length of about 300 bp,of 78 individuals collected from Dalian, Qingdao, Yantai in China and Korea respectively were amplified via PCR, cloned and sequenced. Intra-genomic variation was examined by sequencing several clones of single individuals. Alignment and polymorphism analysis detected 44 haplotypes and 50 polymorphic sites which consist of 30 substitutions and 20 indels, indicating a high level of polymorphisms. Sequence analysis also showed a very low level of intra-individual variation. All these features validated the feasibility of application of ITS - 1 fragment to population analysis. Polymorphism analysis showed that the Korea sample has the richest genetic variation, followed by Yantai and Qingdao samples. AMOVA （analysis of molecular variance） showed that the majority （96.26%） of genetic variation was distributed within populations and 3.74% resulted from among populations, but with P 〈 0.05 （ = 0.042）, indicating that the populations in this study have significant divergence. This output was basically concordant with the result arising from RAPD data and different from that from mitochondrial 16S rDNA sequence data. Discussion on this inconsistency was made accordingly.展开更多
Increasingly,exogenous stressors such as pathogen infections,variable water conditions,and pollution are resulting in high mortality of Paphia undulata,deleteriously affecting the quality of clam harvests.The foot is ...Increasingly,exogenous stressors such as pathogen infections,variable water conditions,and pollution are resulting in high mortality of Paphia undulata,deleteriously affecting the quality of clam harvests.The foot is a burrowing organ in clams.Physical damage and constant contact with the external environment cause the foot to be highly sensitive to pathogen invasion and water condition variation.In the present study,the foot tissue transcriptome was analyzed to identify genes involved in immune and stress responses.The P.undulata transcriptome included 5 286 668 078 bp reads generated by Illumina Hiseq 2000 sequencing and were assembled into 1 785 226 contigs by de novo method.The contigs were clustered into 99 339 transcripts and further grouped into 60 201 unigenes.Of them,22 260 unigenes were successfully annotated using public databases.Twelve genes that were response to immune and stress were identified with abundant expression levels,including heat shock protein 70,cold shock protein,complement C3,cathepsin L,ubiquitin carboxyl-terminal hydrolase L5,and translationally controlled tumor protein.Furthermore,566 unigenes were found homologous to genes involved in the immune response systems of pathogen discrimination,signal transduction,and immune effector,such as lectins,toll-like receptors,complement pathway,toll-like receptor signaling pathway,heat shock proteins,antioxidant enzymes,lysozymes,and mucins,indicating that P.undulata could have a complete set of innate immune mechanisms.In addition,4 270 microsatellite markers(SSRs)were identified from 60 201 unigenes,of which trinucleotide repeats were most abundant and 16 SSRs were tested to be polymorphic.The present study provides a new insight into innate immunity and stress response mechanisms in P.undulata.展开更多
The β18-β19 loop in domain III of Cry1Ac toxin is unique among Bacillus thuringiensis Cry proteins. In this study, the role of the loop structure in insecticidal activity of Cry1Ac toxin was investigated. Alanine sc...The β18-β19 loop in domain III of Cry1Ac toxin is unique among Bacillus thuringiensis Cry proteins. In this study, the role of the loop structure in insecticidal activity of Cry1Ac toxin was investigated. Alanine scanning mutations within the loop were initially generated and most mutants were over-expressed and reduced toxicity at different degrees, except mutant N546A that showed almost 2 times enhanced toxicity against Helicoverpa armigera larvae. Further mutagenic analysis of N546 revealed that a charged amino acid in this position would cause very unfavorable influence on insecticidal activity. In addition, the deletion of N546 led to protein instability because of destruction of the loop integrity. Besides, mutant W544F was much more toxic than W544Y, indicating that hydrophobic nature of the position was important for maintaining the stability and activity of Cry1Ac protein. These findings are the first biological evidence for a structural function of β18-β19 loop in insecticidal activity of the Cry1Ac toxin.展开更多
基金The National Key Technology R&D Program in the 11th Five Year Plan of China under contract No. 2007BAD29B01-2National Department Public Benefit Research Foundation under contract No. nyhyzx 07-048Guangdong Marine and Fishery Bureau under contract Nos A200708C01, A200908A02 and A200908A05
文摘In May of 2007,the second generation selected （SS） and control （SC） groups of pearl oyster Pinctada martensii were established by selecting 10% breeders with the largest and mean shell length,respectively,from the first generation selected group.Growth performance of the SS and SC groups were compared on the basis of measurement data at Days 8,18,60,95,195 and 365.On Day 365,100 individuals （60.0–75.0 mm at shell length） were sampled from each group and then subjected to the experiment where physiological parameters such as filtrate rate,oxygen consumption and ammonia excretion were measured at 15,20,25 and 30°C.The results show that the SS group had significantly larger mean shell length and shell height than the SC group at Days 8,18,60,95,195 and 365 （P 0.05）.The genetic gains at different ages varied from 6.0% to 17.0% for shell length and 5.7% to 14.6% for shell height,respectively.At 15,20,25 and 30 ° C,the SS groups had significantly larger filtrate rate than the SC group （P 0.05）.At 15 and 25 °C,the differences in oxygen consumption rate between the SS and SC groups were not significant （P 0.05）.At 20 and 30 °C,however,the oxygen consumption rate of the SS group was significantly larger than the SC group （P 0.05）.At 15,20,25 and 30 °C,there were no significant differences in ammonia excretion rate between the SS and SC groups （P 0.05）.The present results indicate that there existed considerable genetic variability in the base population and a further selection could be likely fruitful.Mass selection for faster growth might produce animals that had higher intake of metabolizable energy by virtue of faster filtrating behavior.
基金This work was financially supported by the"863"Project of China under contract No.2002AA626020the National Nalural Science Foundation of China under contract No.30570242.
文摘Sequence variation of the first internal transcribed spacer of ribosomal DNA （ ITS - 1 ） was examined and its application to the study of genetic variation was explored in four populations of farter＇ s scallop Chlamys farreri. ITS - 1 fragments, with a length of about 300 bp,of 78 individuals collected from Dalian, Qingdao, Yantai in China and Korea respectively were amplified via PCR, cloned and sequenced. Intra-genomic variation was examined by sequencing several clones of single individuals. Alignment and polymorphism analysis detected 44 haplotypes and 50 polymorphic sites which consist of 30 substitutions and 20 indels, indicating a high level of polymorphisms. Sequence analysis also showed a very low level of intra-individual variation. All these features validated the feasibility of application of ITS - 1 fragment to population analysis. Polymorphism analysis showed that the Korea sample has the richest genetic variation, followed by Yantai and Qingdao samples. AMOVA （analysis of molecular variance） showed that the majority （96.26%） of genetic variation was distributed within populations and 3.74% resulted from among populations, but with P 〈 0.05 （ = 0.042）, indicating that the populations in this study have significant divergence. This output was basically concordant with the result arising from RAPD data and different from that from mitochondrial 16S rDNA sequence data. Discussion on this inconsistency was made accordingly.
基金Supported by the Open Program of Key Laboratory of Cultivation and High-value Utilization of Marine Organisms in Fujian Province(No.2015fjscq05)the Guangdong Province Program,China(Nos.2014B020202011,2016A020208011,A201601A04,20168020233005,2016TQ03N905)+1 种基金the Science and Technology Planning Project of Guangdong Province,China(No.2017B030314052)the China Agriculture Research System(No.CARS-49)
文摘Increasingly,exogenous stressors such as pathogen infections,variable water conditions,and pollution are resulting in high mortality of Paphia undulata,deleteriously affecting the quality of clam harvests.The foot is a burrowing organ in clams.Physical damage and constant contact with the external environment cause the foot to be highly sensitive to pathogen invasion and water condition variation.In the present study,the foot tissue transcriptome was analyzed to identify genes involved in immune and stress responses.The P.undulata transcriptome included 5 286 668 078 bp reads generated by Illumina Hiseq 2000 sequencing and were assembled into 1 785 226 contigs by de novo method.The contigs were clustered into 99 339 transcripts and further grouped into 60 201 unigenes.Of them,22 260 unigenes were successfully annotated using public databases.Twelve genes that were response to immune and stress were identified with abundant expression levels,including heat shock protein 70,cold shock protein,complement C3,cathepsin L,ubiquitin carboxyl-terminal hydrolase L5,and translationally controlled tumor protein.Furthermore,566 unigenes were found homologous to genes involved in the immune response systems of pathogen discrimination,signal transduction,and immune effector,such as lectins,toll-like receptors,complement pathway,toll-like receptor signaling pathway,heat shock proteins,antioxidant enzymes,lysozymes,and mucins,indicating that P.undulata could have a complete set of innate immune mechanisms.In addition,4 270 microsatellite markers(SSRs)were identified from 60 201 unigenes,of which trinucleotide repeats were most abundant and 16 SSRs were tested to be polymorphic.The present study provides a new insight into innate immunity and stress response mechanisms in P.undulata.
基金the National High Technology Research and Development Program of China (Grant No. 2006AA02Z187, 2006AA10A212)National Natural Science Foundation of China (Grant No. 30670052)Ph.D. Programs Foundation of Ministry of Education of China (Grant No. 20060452006)
文摘The β18-β19 loop in domain III of Cry1Ac toxin is unique among Bacillus thuringiensis Cry proteins. In this study, the role of the loop structure in insecticidal activity of Cry1Ac toxin was investigated. Alanine scanning mutations within the loop were initially generated and most mutants were over-expressed and reduced toxicity at different degrees, except mutant N546A that showed almost 2 times enhanced toxicity against Helicoverpa armigera larvae. Further mutagenic analysis of N546 revealed that a charged amino acid in this position would cause very unfavorable influence on insecticidal activity. In addition, the deletion of N546 led to protein instability because of destruction of the loop integrity. Besides, mutant W544F was much more toxic than W544Y, indicating that hydrophobic nature of the position was important for maintaining the stability and activity of Cry1Ac protein. These findings are the first biological evidence for a structural function of β18-β19 loop in insecticidal activity of the Cry1Ac toxin.
