Calreticulin(CRT)is a highly conserved Ca2+-binding protein and chaperone in the endoplasmic reticulum,which mainly participates in adjusting calcium level and directing proper conformation of proteins.Here,we cloned ...Calreticulin(CRT)is a highly conserved Ca2+-binding protein and chaperone in the endoplasmic reticulum,which mainly participates in adjusting calcium level and directing proper conformation of proteins.Here,we cloned the crt gene of the scleractinian coral Galaxea astreata,named Gacrt,and analysed its ability to drive bacterial agglutination.The full-length Gacrt cDNA consisted of 1792 nucleotides and contained a 77 bp 5’untranslated region(UTR),a 380 bp 3’UTR and a 1335 bp open reading frame(ORF)that encoded a 444 amino acid protein.The deduced peptide possessed a signal peptide domain,an endoplasmic reticulum retrieval signal sequence(KDEL),two potential calreticulin family signature motifs and a set of triplicate repeats.We also found that the recombinant GaCRT protein could promote agglutination of both the Gram-positive bacterium Micrococcus luteus and the Gram-negative bacterium Escherichia coli.These results show that the GaCRT protein can enhance bacterial agglutination,hinting that GaCRT is an immune-relevant molecule involved in host defense against bacterium.展开更多
Scleractinian corals host numerous microbial symbionts with different types of interactions. The gastric cavity of scleractinian coral, as a semiclosed subenvironment with distinct chemical characteristics(e.g., disso...Scleractinian corals host numerous microbial symbionts with different types of interactions. The gastric cavity of scleractinian coral, as a semiclosed subenvironment with distinct chemical characteristics(e.g., dissolved O2, pH, alkalinity, and nutrients), harbors a distinct microbial community and a diverse array of bacteria that can be pathogenic or beneficial. Galaxea fascicularis is one of the dominant massive scleractinian coral species on inshore fringing reefs in the northern South China Sea.Although the abundance of coral-associated bacteria has been investigated in G. fascicularis, less is known about the microorganisms in the gastric cavity. In this study, we specially isolated cultivable bacterial strains from the gastric cavity of G.fascicularis collected from Hainan Island using a noninvasive sampling approach. Among the 101 representative bacterial strains, one Vibrio coralliilyticus strain, SCSIO 43001, was found to be a temperature-dependent opportunistic pathogen of G.fascicularis. The antagonistic activity between the 100 strains and V. coralliilyticus SCSIO 43001 was tested using a modified Burkholder diffusion assay. Our results showed that V. coralliilyticus SCSIO 43001 inhibits the growth of Erythrobacter flavus and Sphingomonas yabuuchiae. Additionally, we found that three Pseudoalteromonas strains showed moderate to high antibacterial activity against V. coralliilyticus SCSIO 43001 and several other coral-associated Gram-negative bacterial strains.These results suggest that competition between the coral pathogen and other bacteria also occurs in the gastric cavity of coral, and Pseudoalteromonas strains in the gastric cavity of G. fascicularis may provide a protective role in the defense against coinhabiting coral pathogens at elevated temperature.展开更多
Coral fluorescence phenotypes have been suggested as an adaptation to a broad range of environmental conditions,yet the mechanisms linking thermal bleaching tolerance in reef-building coral populations,associated with...Coral fluorescence phenotypes have been suggested as an adaptation to a broad range of environmental conditions,yet the mechanisms linking thermal bleaching tolerance in reef-building coral populations,associated with fluorescence phenotypes due to GFP-like proteins,remains unclear.In this study,the relationship between the thermal sensitivity and phenotypic plasticity of corals was investigated using two phenotypes of Galaxea fascicularis,green and brown.The results reveal that brown G.fascicularis was more susceptible to bleaching than green G.fascicularis when exposed to a higher growth temperature of 32℃.Both phenotypes of G.fascicularis were associated with the thermotolerant Symbiodiniaceae symbiont,Durusdinium trenchii.However,the brown G.fascicularis showed a significant decrease in Symbiodiniaceae cell density and a significant increase in pathogenic bacteria abundance when the growth temperature was raised from 29 to 32℃.The physiological traits and transcriptomic profiles of Symbiodiniaceae were not notably affected,but there were differences in the transcriptional levels of certain genes between the two phenotype hosts of G.fascicularis.Under heat stress of 32℃,the gene encoding green fluorescent protein(GFP)-like and chromosome-associated proteins,as well as genes related to oxidative phosphorylation,cell growth and death showed lower transcriptional levels in the brown G.fascicularis compared to the green G.fascicularis.Overall,the results demonstrate that the green form of G.fascicularis is better able to tolerate ocean warming and defend against pathogenic bacteria,likely due to higher gene transcription levels and defense ability.展开更多
Due to the elevated atmospheric carbon dioxide, ocean acidification(OA) has recently emerged as a research theme in marine biology due to an expected deleterious effect of altered seawater chemistry on calcification. ...Due to the elevated atmospheric carbon dioxide, ocean acidification(OA) has recently emerged as a research theme in marine biology due to an expected deleterious effect of altered seawater chemistry on calcification. A system simulating future OA scenario is crucial for OA-related studies. Here, we designed an OA-simulated system(OASys) with three solenoid-controlled CO_2 gas channels. The OASys can adjust the pH of the seawater by bubbling CO_2 gas into seawaters via feedback systems. The OASys is very simple in structure with an integrated design and is new-user friendly with the instruction. Moreover, the OASys can monitor and record real-time pH values and can maintain pH levels within 0.02 pH unit. In a 15-d experiment, the OASys was applied to simulate OA in which the expected target pH values were 8.00, 7.80 and 7.60 to study the calcifying response of Galaxea fascicularis. The results showed daily mean seawater pH values held at pH 8.00±0.01, 7.80±0.01 and 7.61±0.01 over15 d. Correspondingly, the coral calcification of G. fascicularis gradually decreased with reduced pH.展开更多
以高通量测序技术Illumina Hi SeqTM2000对稀杯盔形珊瑚(Galaxea astreata)进行转录组测序分析,共获得50 360 620条短序列(reads)。利用Trinity软件对所有reads从头组装后得到81 014条单基因簇(Unigenes),60 471条(74.58%)编码蛋白框(Co...以高通量测序技术Illumina Hi SeqTM2000对稀杯盔形珊瑚(Galaxea astreata)进行转录组测序分析,共获得50 360 620条短序列(reads)。利用Trinity软件对所有reads从头组装后得到81 014条单基因簇(Unigenes),60 471条(74.58%)编码蛋白框(Coding Sequences,CDs)。与Nr(Non-redundant,非冗余)、COG(Cluster of Orthologous Groups of proteins,蛋白相邻类的聚簇)、KEGG(Kyoto encyclopedia of genes and genomes,京都基因与基因组百科全书)、Swissprot四大数据库比对共获得36 545条注释基因。其中与COG数据库比对获得14 491条注释基因,分为24个功能类别,其中参与一般功能预测类的Unigene数最多,有4 642条;KEGG分析比对获得16 021条注释基因,分成241类,包括代谢通路、钙离子信号通路、MAPK信号通路等,在所有通路中参与代谢途径的基因数最多,共有2 450条(15.29%);GO(Gene Ontology,基因本体)功能分类将Unigene分为47个类别。展开更多
在丛生盔形珊瑚中分离得到1株形态特殊的共附生真菌XWC14-13,对其鉴定并进行生理学特性研究,为该类珊瑚共附生真菌的进一步研究提供参考。通过观察菌株XWC14-13在CA和PDA培养基的生长特性及个体特征,结合r DNA ITS1-ITS4基因序列的系统...在丛生盔形珊瑚中分离得到1株形态特殊的共附生真菌XWC14-13,对其鉴定并进行生理学特性研究,为该类珊瑚共附生真菌的进一步研究提供参考。通过观察菌株XWC14-13在CA和PDA培养基的生长特性及个体特征,结合r DNA ITS1-ITS4基因序列的系统发育分析,将其鉴定为卵形孢球托霉(Gongronella butleri)。该菌株菌丝宽度为3.62~8.09μm,有膈膜,不产厚垣孢子,孢子囊大小为(5.15~7.57)μm×(23.53~25.74)μm,孢囊孢子大小为(2.02~3.03)μm×(1.52~2.01)μm。其生长温度、酸碱度和盐度的适应性研究结果表明,该菌最适生长条件为温度30℃,pH 8~8.5,盐度1%,具有一定的耐盐性及酸碱耐受性,属兼性海洋真菌。展开更多
Nitrogen cycle is critical to maintain a healthy coral reef ecosystem.Urea can provide a source of nitrogen for coral holobiont and is important for coral calcification through degradation by urease.Despite the involv...Nitrogen cycle is critical to maintain a healthy coral reef ecosystem.Urea can provide a source of nitrogen for coral holobiont and is important for coral calcification through degradation by urease.Despite the involvement of coral-associated bacteria in nitrogen fixation,nitrification and denitrification are well recognized,to what extend urea degradation by bacteria contributing to the urea utilization by coral holobiont remains to be investigated.In this study,we demonstrate that the urea utilization is a common feature of Halomonas spp.that is a dominant genus in cultivable coral-associated bacteria.A urease operon was characterized by genome sequencing and gene knock-out technique in Halomonas meridiana SCSIO 43005,isolated from the gastric cavity of healthy scleractinian coral Galaxea fascicularis.H.meridiana showed high urease activity which was induced by urea and deletion of the urease operon reduced the capability to use urea as solo nitrogen source.Furthermore,approximately 1/3 coral-associated bacteria in the IMG/M database possess complete urease operons indicating the involvement of bacteria-derived ureases in coral holobiont.These results suggest that urease from coral-associated bacteria might be important player in the nitrogen cycling of coral reefs.展开更多
基金The National Marine Welfare Industry Research Project under contract No.201105012the Guangdong Provincial Natural Science Foundation under contract No.S2011010000269+1 种基金the Guangdong Marine Fishery Science and Technology Extension Project under contract No.A201308E02the Guangdong Ocean University Scientific Research Start-up Fund for the Doctoral Program under contract No.R17066。
文摘Calreticulin(CRT)is a highly conserved Ca2+-binding protein and chaperone in the endoplasmic reticulum,which mainly participates in adjusting calcium level and directing proper conformation of proteins.Here,we cloned the crt gene of the scleractinian coral Galaxea astreata,named Gacrt,and analysed its ability to drive bacterial agglutination.The full-length Gacrt cDNA consisted of 1792 nucleotides and contained a 77 bp 5’untranslated region(UTR),a 380 bp 3’UTR and a 1335 bp open reading frame(ORF)that encoded a 444 amino acid protein.The deduced peptide possessed a signal peptide domain,an endoplasmic reticulum retrieval signal sequence(KDEL),two potential calreticulin family signature motifs and a set of triplicate repeats.We also found that the recombinant GaCRT protein could promote agglutination of both the Gram-positive bacterium Micrococcus luteus and the Gram-negative bacterium Escherichia coli.These results show that the GaCRT protein can enhance bacterial agglutination,hinting that GaCRT is an immune-relevant molecule involved in host defense against bacterium.
基金supported by the National Key R & D Program of China (Grant Nos. 2018YFC1406500 & 2017YFC0506303)the National Natural Science Foundation of China (Grant Nos. 41706172, 31625001 & 41376174)the Hainan Provincial Key R & D (Grant No. ZDYF2018108)
文摘Scleractinian corals host numerous microbial symbionts with different types of interactions. The gastric cavity of scleractinian coral, as a semiclosed subenvironment with distinct chemical characteristics(e.g., dissolved O2, pH, alkalinity, and nutrients), harbors a distinct microbial community and a diverse array of bacteria that can be pathogenic or beneficial. Galaxea fascicularis is one of the dominant massive scleractinian coral species on inshore fringing reefs in the northern South China Sea.Although the abundance of coral-associated bacteria has been investigated in G. fascicularis, less is known about the microorganisms in the gastric cavity. In this study, we specially isolated cultivable bacterial strains from the gastric cavity of G.fascicularis collected from Hainan Island using a noninvasive sampling approach. Among the 101 representative bacterial strains, one Vibrio coralliilyticus strain, SCSIO 43001, was found to be a temperature-dependent opportunistic pathogen of G.fascicularis. The antagonistic activity between the 100 strains and V. coralliilyticus SCSIO 43001 was tested using a modified Burkholder diffusion assay. Our results showed that V. coralliilyticus SCSIO 43001 inhibits the growth of Erythrobacter flavus and Sphingomonas yabuuchiae. Additionally, we found that three Pseudoalteromonas strains showed moderate to high antibacterial activity against V. coralliilyticus SCSIO 43001 and several other coral-associated Gram-negative bacterial strains.These results suggest that competition between the coral pathogen and other bacteria also occurs in the gastric cavity of coral, and Pseudoalteromonas strains in the gastric cavity of G. fascicularis may provide a protective role in the defense against coinhabiting coral pathogens at elevated temperature.
基金supported by the Opening Project of Guangxi Laboratory on the Study of Coral Reefs in the South China Sea,Nanning 530004,China(GXLSCRSCS2019003)Natural Science Foundation of Guang Dong(2022A1515010521)+2 种基金the National Natural Science Foundation of China(31971501)The CAS Pioneer Hundred Talents Program(Y8SL031001,Y9YB021001)Science and Technology Program of Guangzhou,China(202002030345).
文摘Coral fluorescence phenotypes have been suggested as an adaptation to a broad range of environmental conditions,yet the mechanisms linking thermal bleaching tolerance in reef-building coral populations,associated with fluorescence phenotypes due to GFP-like proteins,remains unclear.In this study,the relationship between the thermal sensitivity and phenotypic plasticity of corals was investigated using two phenotypes of Galaxea fascicularis,green and brown.The results reveal that brown G.fascicularis was more susceptible to bleaching than green G.fascicularis when exposed to a higher growth temperature of 32℃.Both phenotypes of G.fascicularis were associated with the thermotolerant Symbiodiniaceae symbiont,Durusdinium trenchii.However,the brown G.fascicularis showed a significant decrease in Symbiodiniaceae cell density and a significant increase in pathogenic bacteria abundance when the growth temperature was raised from 29 to 32℃.The physiological traits and transcriptomic profiles of Symbiodiniaceae were not notably affected,but there were differences in the transcriptional levels of certain genes between the two phenotype hosts of G.fascicularis.Under heat stress of 32℃,the gene encoding green fluorescent protein(GFP)-like and chromosome-associated proteins,as well as genes related to oxidative phosphorylation,cell growth and death showed lower transcriptional levels in the brown G.fascicularis compared to the green G.fascicularis.Overall,the results demonstrate that the green form of G.fascicularis is better able to tolerate ocean warming and defend against pathogenic bacteria,likely due to higher gene transcription levels and defense ability.
基金The China-ASEAN Maritime Cooperation Fund Project "China-ASEAN Countries Collaboration on Marine Endangered Species Researches" and "China-ASEAN Marine Protected Areas Ecosystem Management Network"Regional Demonstration of Marine Economy Innovative Development Project under contract No.16PZY002SF18+1 种基金the China-Indonesia Maritime Cooperation Fund Project "China-Indonesia Bitung Ecological Station Establishment"the National Natural Science Foundation of China under contract No.41506123
文摘Due to the elevated atmospheric carbon dioxide, ocean acidification(OA) has recently emerged as a research theme in marine biology due to an expected deleterious effect of altered seawater chemistry on calcification. A system simulating future OA scenario is crucial for OA-related studies. Here, we designed an OA-simulated system(OASys) with three solenoid-controlled CO_2 gas channels. The OASys can adjust the pH of the seawater by bubbling CO_2 gas into seawaters via feedback systems. The OASys is very simple in structure with an integrated design and is new-user friendly with the instruction. Moreover, the OASys can monitor and record real-time pH values and can maintain pH levels within 0.02 pH unit. In a 15-d experiment, the OASys was applied to simulate OA in which the expected target pH values were 8.00, 7.80 and 7.60 to study the calcifying response of Galaxea fascicularis. The results showed daily mean seawater pH values held at pH 8.00±0.01, 7.80±0.01 and 7.61±0.01 over15 d. Correspondingly, the coral calcification of G. fascicularis gradually decreased with reduced pH.
文摘以高通量测序技术Illumina Hi SeqTM2000对稀杯盔形珊瑚(Galaxea astreata)进行转录组测序分析,共获得50 360 620条短序列(reads)。利用Trinity软件对所有reads从头组装后得到81 014条单基因簇(Unigenes),60 471条(74.58%)编码蛋白框(Coding Sequences,CDs)。与Nr(Non-redundant,非冗余)、COG(Cluster of Orthologous Groups of proteins,蛋白相邻类的聚簇)、KEGG(Kyoto encyclopedia of genes and genomes,京都基因与基因组百科全书)、Swissprot四大数据库比对共获得36 545条注释基因。其中与COG数据库比对获得14 491条注释基因,分为24个功能类别,其中参与一般功能预测类的Unigene数最多,有4 642条;KEGG分析比对获得16 021条注释基因,分成241类,包括代谢通路、钙离子信号通路、MAPK信号通路等,在所有通路中参与代谢途径的基因数最多,共有2 450条(15.29%);GO(Gene Ontology,基因本体)功能分类将Unigene分为47个类别。
文摘在丛生盔形珊瑚中分离得到1株形态特殊的共附生真菌XWC14-13,对其鉴定并进行生理学特性研究,为该类珊瑚共附生真菌的进一步研究提供参考。通过观察菌株XWC14-13在CA和PDA培养基的生长特性及个体特征,结合r DNA ITS1-ITS4基因序列的系统发育分析,将其鉴定为卵形孢球托霉(Gongronella butleri)。该菌株菌丝宽度为3.62~8.09μm,有膈膜,不产厚垣孢子,孢子囊大小为(5.15~7.57)μm×(23.53~25.74)μm,孢囊孢子大小为(2.02~3.03)μm×(1.52~2.01)μm。其生长温度、酸碱度和盐度的适应性研究结果表明,该菌最适生长条件为温度30℃,pH 8~8.5,盐度1%,具有一定的耐盐性及酸碱耐受性,属兼性海洋真菌。
基金supported by the National Key R&D Program of China(Grant Nos.2017YFC0506303&2018YFC1406500)the National Natural Science Foundation of China(Grant Nos.91951203,41706172,31625001&41376174)+2 种基金the Hainan Provincial Key R&D Program(Grant No.ZDYF2018108)supported by the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(Grant No.GML2019ZD0407)the Guangdong Local Innovation Team Program(Grant No.2019BT02Y262)。
文摘Nitrogen cycle is critical to maintain a healthy coral reef ecosystem.Urea can provide a source of nitrogen for coral holobiont and is important for coral calcification through degradation by urease.Despite the involvement of coral-associated bacteria in nitrogen fixation,nitrification and denitrification are well recognized,to what extend urea degradation by bacteria contributing to the urea utilization by coral holobiont remains to be investigated.In this study,we demonstrate that the urea utilization is a common feature of Halomonas spp.that is a dominant genus in cultivable coral-associated bacteria.A urease operon was characterized by genome sequencing and gene knock-out technique in Halomonas meridiana SCSIO 43005,isolated from the gastric cavity of healthy scleractinian coral Galaxea fascicularis.H.meridiana showed high urease activity which was induced by urea and deletion of the urease operon reduced the capability to use urea as solo nitrogen source.Furthermore,approximately 1/3 coral-associated bacteria in the IMG/M database possess complete urease operons indicating the involvement of bacteria-derived ureases in coral holobiont.These results suggest that urease from coral-associated bacteria might be important player in the nitrogen cycling of coral reefs.
