By air-dry method, the karyotype from gill cell in three clams of Bivalvia Pterimorphia Arcidae,Tegillarca granosa,Scapharca subcrenata and S.broughtonii,was studied. Their chromosome number (2n ) andfundamenod number...By air-dry method, the karyotype from gill cell in three clams of Bivalvia Pterimorphia Arcidae,Tegillarca granosa,Scapharca subcrenata and S.broughtonii,was studied. Their chromosome number (2n ) andfundamenod number (W) are equal to each other. But their karyotype is different. In T. granosa, it is 2n = 38,28m+ 10sml In S.subcrenata2n = 38, 14m + 22sm+ 2st, In S.broughtonii 2n = 38, 12m+ 20sm+ 6st. T.granosa has no subtelocentric (st) chromosome, S.subcrenata has one Pair and S. then has three paris of st.Middle centric (m) and submiddle centric chromosome are major type in karyotype of three species of Arcida; thelengths of chromosomes from the largest to the smallest changed gradually. The absolute length of the maximum chromosome in all three species do not exceed 5 μm and the minimum cluomonsome is about 2 μm. Inversion pericentricperhaps plays an important role in the evolution of chromosome. Hybridization among the three species of Arcidae ispossible.展开更多
Phenoloxidases(POs)are a group of copper proteins including tyrosinase,catecholase and laccase,which play crucial roles in the innate immune response of mollusks.In this research,POs were studied in cultured mollusk s...Phenoloxidases(POs)are a group of copper proteins including tyrosinase,catecholase and laccase,which play crucial roles in the innate immune response of mollusks.In this research,POs were studied in cultured mollusk species,including scallop Chla-mys farreri,abalone Haliotis discus hannai and clam Scapharca subcrenata.The POs were isolated from hemocytes using linear-gradient native-PAGE combined with catechol staining.The PO activities and their characters were investigated.The molecular mass of PO in C.farreri was 576 kDa,and it was 228 kDa in H.discus hannai.In S.subcrenata,four POs were detected and their mole-cular masses were 391 kDa,206 kDa,174 kDa and<67 kDa,which were named as 391-PO,206-PO,174-PO and s-PO,respectively.Ki-netic analyses indicated that all of the POs,except for 391-PO had higher affinity to L-DOPA and catechol than to hydroquinone and dopamine.However,all of the POs failed to oxidize tyrosine.The effects of divalent metal ions on POs’activities were assayed,in-cluding Fe^(2+),Mg^(2+),Zn^(2+),Mn^(2+),Cu^(2+)and Ca^(2+)from FeCl_(2),MgSO_(4),ZnSO_(4),MnCl_(2),CuSO_(4)and CaCl_(2).The POs were inhibited by Fe^(2+)at all determined concentrations.Additionally,the inhibition assay showed that all of the POs were inhibited by cysteine,ascorbic acid,sodium sulfite,citric acid,ethylenediaminetetraacetic acid disodium(EDTA)and sodium diethyldithiocarbamate(DETC).The inhibition effects of critric acid and EDTA are dose-dependent.H.discus hannai PO and 391-PO were slightly inhibited by sodium azide,and H.discus hannai PO,391-PO and 174-PO were slightly inhibited by thiourea.In conclusion,the POs in the three cultured mollusks are copper-containing laccase-type phenoloxidases with similar biochemical characteristics even though their molecular masses are different.展开更多
The relationships between nutrient dynamics,microbial community,and macrofauna are important in bioremediation systems.In this study,we examined the effects of marine clam Scapharca subcrenata sedimentary activities o...The relationships between nutrient dynamics,microbial community,and macrofauna are important in bioremediation systems.In this study,we examined the effects of marine clam Scapharca subcrenata sedimentary activities on the microbial assemblages,benthic nutrient chemistry,and its subsequent remediation impacts on organic effluent in the sediment of an aquaculture wastewater bioremediation system.The results showed that microbial community composition differed significantly in the clam area(ANOSIM,R=0.707,P=0.037).Pyrosequencing of bacterial 16S rRNA gene revealed a total of 48 unique phyla,79 classes,107 orders,197 families,and 321 genera amongst all samples.The most dominant bacterial assemblages were Proteobacteria,Bacteroidetes,Acidobacteria,Firmicutes,Verrucomicrobia,and Actinobacteria,with Bacteroidetes and Firmicutes significantly higher in all treatment samples than control(P<0.001).All dominant phyla in the list were shared across all samples and accounted for 89%(control)and 97%(treatment)of the total 16S rRNA.The nutrient flux rates from the sediments into the water(treatment group)were 51%(ammonium),88%(nitrate),77%(nitrite)and 45%(phosphate)higher,relative to the control implying increased mineralization,degradability,and mobility of the benthic nutrients.Similarly,significantly increased oxygen consumption rates were evident in the clam area signifying improved oxygen distribution within the sediment.The organic effluent contents associated with total-organic matter,carbon,nitrogen,and,phosphate were lower among the clam treatments relative to the control.Our results describe the potential roles and mechanisms contributed by marine bivalve S.subcrenata on benthic-bacterial-community assembly,nutrient balance,and effluent reduction in the sediments of aquaculture wastewaters bioremediation system.展开更多
文摘By air-dry method, the karyotype from gill cell in three clams of Bivalvia Pterimorphia Arcidae,Tegillarca granosa,Scapharca subcrenata and S.broughtonii,was studied. Their chromosome number (2n ) andfundamenod number (W) are equal to each other. But their karyotype is different. In T. granosa, it is 2n = 38,28m+ 10sml In S.subcrenata2n = 38, 14m + 22sm+ 2st, In S.broughtonii 2n = 38, 12m+ 20sm+ 6st. T.granosa has no subtelocentric (st) chromosome, S.subcrenata has one Pair and S. then has three paris of st.Middle centric (m) and submiddle centric chromosome are major type in karyotype of three species of Arcida; thelengths of chromosomes from the largest to the smallest changed gradually. The absolute length of the maximum chromosome in all three species do not exceed 5 μm and the minimum cluomonsome is about 2 μm. Inversion pericentricperhaps plays an important role in the evolution of chromosome. Hybridization among the three species of Arcidae ispossible.
基金supported by the Qingdao National La-boratory for Marine Science and Technology(No.QNLM 2016ORP0307)the National Key Research and Develop-ment Program of China(No.YFD0900504)+1 种基金the National Basic Research Program of China(No.2012CB114405)the Taishan Scholar Program of Shandong Province.
文摘Phenoloxidases(POs)are a group of copper proteins including tyrosinase,catecholase and laccase,which play crucial roles in the innate immune response of mollusks.In this research,POs were studied in cultured mollusk species,including scallop Chla-mys farreri,abalone Haliotis discus hannai and clam Scapharca subcrenata.The POs were isolated from hemocytes using linear-gradient native-PAGE combined with catechol staining.The PO activities and their characters were investigated.The molecular mass of PO in C.farreri was 576 kDa,and it was 228 kDa in H.discus hannai.In S.subcrenata,four POs were detected and their mole-cular masses were 391 kDa,206 kDa,174 kDa and<67 kDa,which were named as 391-PO,206-PO,174-PO and s-PO,respectively.Ki-netic analyses indicated that all of the POs,except for 391-PO had higher affinity to L-DOPA and catechol than to hydroquinone and dopamine.However,all of the POs failed to oxidize tyrosine.The effects of divalent metal ions on POs’activities were assayed,in-cluding Fe^(2+),Mg^(2+),Zn^(2+),Mn^(2+),Cu^(2+)and Ca^(2+)from FeCl_(2),MgSO_(4),ZnSO_(4),MnCl_(2),CuSO_(4)and CaCl_(2).The POs were inhibited by Fe^(2+)at all determined concentrations.Additionally,the inhibition assay showed that all of the POs were inhibited by cysteine,ascorbic acid,sodium sulfite,citric acid,ethylenediaminetetraacetic acid disodium(EDTA)and sodium diethyldithiocarbamate(DETC).The inhibition effects of critric acid and EDTA are dose-dependent.H.discus hannai PO and 391-PO were slightly inhibited by sodium azide,and H.discus hannai PO,391-PO and 174-PO were slightly inhibited by thiourea.In conclusion,the POs in the three cultured mollusks are copper-containing laccase-type phenoloxidases with similar biochemical characteristics even though their molecular masses are different.
基金This study was supported by the Zhejiang Public Welfare Technology Research Program of China(ZPWTP)(No.LGN18C190008)the Zhejiang Provincial Natural Science Foundation of China(No.LQ20C190003)the Ningbo Municipal Natural Science Foundation(Nos.2019A610421,2019A610443),and the K.C.Wong Magna Fund in Ningbo University.
文摘The relationships between nutrient dynamics,microbial community,and macrofauna are important in bioremediation systems.In this study,we examined the effects of marine clam Scapharca subcrenata sedimentary activities on the microbial assemblages,benthic nutrient chemistry,and its subsequent remediation impacts on organic effluent in the sediment of an aquaculture wastewater bioremediation system.The results showed that microbial community composition differed significantly in the clam area(ANOSIM,R=0.707,P=0.037).Pyrosequencing of bacterial 16S rRNA gene revealed a total of 48 unique phyla,79 classes,107 orders,197 families,and 321 genera amongst all samples.The most dominant bacterial assemblages were Proteobacteria,Bacteroidetes,Acidobacteria,Firmicutes,Verrucomicrobia,and Actinobacteria,with Bacteroidetes and Firmicutes significantly higher in all treatment samples than control(P<0.001).All dominant phyla in the list were shared across all samples and accounted for 89%(control)and 97%(treatment)of the total 16S rRNA.The nutrient flux rates from the sediments into the water(treatment group)were 51%(ammonium),88%(nitrate),77%(nitrite)and 45%(phosphate)higher,relative to the control implying increased mineralization,degradability,and mobility of the benthic nutrients.Similarly,significantly increased oxygen consumption rates were evident in the clam area signifying improved oxygen distribution within the sediment.The organic effluent contents associated with total-organic matter,carbon,nitrogen,and,phosphate were lower among the clam treatments relative to the control.Our results describe the potential roles and mechanisms contributed by marine bivalve S.subcrenata on benthic-bacterial-community assembly,nutrient balance,and effluent reduction in the sediments of aquaculture wastewaters bioremediation system.
