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海洋生命科学与技术（英文）
海洋生命科学与技术（英文）
海洋生命科学与技术（英文）/Journal Marine Life Science & TechnologyCSCDSCI
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    RebL1 is required for macronuclear structure stability and gametogenesis in Tetrahymena thermophila

    Huijuan HaoYinjie LianChenhui RenSitong Yang...
    183-197页
    查看更多>>摘要：Histone modification and nucleosome assembly play important roles in chromatin-related processes.Histone chaperones form different complexes and coordinate histone transportation and assembly.Various histone chaperone complexes have been identified in different organisms.The ciliate protozoa(ciliates)have various chromatin structures and different nuclear morphology.However,histone chaperone components and functions of different subunits remain unclear in ciliates.Tet-rahymema thermophila contains a transcriptionally active macronucleus(MAC)and a transcriptionally inactive micronu-cleus(MIC)which exhibit multiple replication and various chromatin remodeling progresses during vegetative growth and sexual developmental stages.Here,we found histone chaperone RebL1 not only localized evenly in the transcriptionally active MAC but also dynamically changed in the MIC during vegetative growth and sexual developmental stages.REBL1 knockdown inhibited cellular proliferation.The macronuclear morphology became bigger in growing mutants.The abnormal macronuclear structure also occurred in the starvation stage.Furthermore,micronuclear meiosis was disturbed during sexual development,leading to a failure to generate new gametic nuclei.RebL1 potentially interacted with various factors involved in histone-modifying complexes and chromatin remodeling complexes in different developmental stages.REBL1 knockdown affected expression levels of the genes involved in chromatin organization and transcription.Taken together,RebL1 plays a vital role in maintaining macronuclear structure stability and gametogenesis in T.thermophila.
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    Spontaneous mutations and mutational responses to penicillin treatment in the bacterial pathogen Streptococcus pneumoniae D39

    Wanyue JiangTongtong LinJiao PanCaitlyn E.Rivera...
    198-211页
    查看更多>>摘要：Bacteria with functional DNA repair systems are expected to have low mutation rates due to strong natural selection for genomic stability.However,our study of the wild-type Streptococcus pneumoniae D39,a pathogen responsible for many common diseases,revealed a high spontaneous mutation rate of 0.02 per genome per cell division in mutation-accumulation(MA)lines.This rate is orders of magnitude higher than that of other non-mutator bacteria and is characterized by a high mutation bias in the A/T direction.The high mutation rate may have resulted from a reduction in the overall efficiency of selection,conferred by the tiny effective population size in nature.In line with this,S.pneumoniae D39 also exhibited the lowest DNA mismatch-repair(MMR)efficiency among bacteria.Treatment with the antibiotic penicillin did not elevate the mutation rate,as penicillin did not induce DNA damage and S.pneumoniae lacks a stress response pathway.Our findings suggested that the MA results are applicable to within-host scenarios and provide insights into pathogen evolution.
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    Findings on three endocommensal scuticociliates(Protista,Ciliophora)from freshwater mollusks,including their morphology and molecular phylogeny with descriptions of two new species

    Tao LiTengyue ZhangMingjian LiuZhe Zhang...
    212-235页
    查看更多>>摘要：Species of the ciliate genera Myxophyllum and Conchophthirus are found as endocommensals of terrestrial and freshwater mollusks,respectively.So far,there have been few studies of these genera and morphological data for most members are often incomplete.In the present work,two new species,Myxophyllum weishanense sp.nov.and Conchophthirus paracurtus sp.nov.,and a known species,Conchophthirus lamellidens,were isolated from hosts in Lake Weishan Wetland,China.Taxonomic studies indicate that M.weishanense sp.nov.can be recognized mainly by the combination of about 60 somatic kineties on both ventral and dorsal sides and the presence of caudal cilia.Conchophthirus paracurtus sp.nov.differs from congeners in its body shape and size,having a glabrous area on the posterior right side,and having fewer somatic kineties.In addition,differences in their ITS2(Internally Transcribed Spacer 2)secondary structures support the discrimination of the two new species from their highly similar congeners.An improved diagnosis for the poorly known species,C.lamel-lidens is also provided.Phylogenetic analyses reveal that members of the genus Myxophyllum belong to a fully supported clade that is sister to a large,poorly supported clade consisting of Hemispeiridae,Ancistridae,and several lineages of the nonmonophyletic Cyclidiidae.The Myxophyllum clade also includes Protophyra ovicola JQ956552,a possible misidenti-fication.Sequences of the two new Conchophthirus species cluster with other congeners in a fully supported clade that is unrelated to either the'typical'thigmotrichs or to pleuronematids,thus conflicting with the traditional classification,and may represent an orphan scuticociliate lineage.
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    Dominance of transposable element-related satDNAs results in great complexity of"satDNA library"and invokes the extension towards"repetitive DNA library"

    Monika Tunjić-CvitanićDaniel García-SoutoJuan J.PasantesEva Šatović-Vukšić...
    236-251页
    查看更多>>摘要：Research on bivalves is fast-growing,including genome-wide analyses and genome sequencing.Several characteristics qualify oysters as a valuable model to explore repetitive DNA sequences and their genome organization.Here we char-acterize the satellitomes of five species in the family Ostreidae(Crassostrea angulata,C.virginica,C.hongkongensis,C.ariakensis,Ostrea edulis),revealing a substantial number of satellite DNAs(satDNAs)per genome(ranging between 33 and 61)and peculiarities in the composition of their satellitomes.Numerous satDNAs were either associated to or derived from transposable elements,displaying a scarcity of transposable element-unrelated satDNAs in these genomes.Due to the non-conventional satellitome constitution and dominance of Helitron-associated satDNAs,comparative satellitomics demanded more in-depth analyses than standardly employed.Comparative analyses(including C.gigas,the first bivalve species with a defined satellitome)revealed that 13 satDNAs occur in all six oyster genomes,with Cg170/HindⅢ satDNA being the most abundant in all of them.Evaluating the"satDNA library model"highlighted the necessity to adjust this term when studying tandem repeat evolution in organisms with such satellitomes.When repetitive sequences with potential variation in the organizational form and repeat-type affiliation are examined across related species,the introduction of the terms"TE library"and"repetitive DNA library"becomes essential.
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    Identification and functional characterization offish IL-17 receptors suggest important roles in the response to nodavirus infection

    Carmen González-FernándezMiguel A.García-ÁlvarezAlberto Cuesta
    252-265页
    查看更多>>摘要：Th17 is a lymphocyte T helper(Th)subpopulation relevant in the control and regulation of the immune response characterized by the production of interleukin(IL)-17.This crucial cytokine family acts through their binding to the IL-17 receptors(IL-17R),having up to six members.Although the biology of fish Th17 is well-recognized,the molecular and functional characterization of IL-17 and IL-17R has been limited.Thus,our aim was to identify and characterize the IL-17R repertory and regulation in the two main Mediterranean cultured fish species,the gilthead seabream(Sparus aurata)and the European sea bass(Dicentrarchus labrax).Our in silico results showed the clear identification of six members in each fish species,from IL-17RA to IL-17RE-like,with well-conserved gene structure and protein domains with their human orthologues.All of them showed wide and constitutive transcription in naive tissues but with highest levels in mucosal tissues,namely skin,gill or intestine.In leucocytes,T mitogens showed the strongest up-regulation in most of the il17 receptors though il17ra resulted in inhibition by most stimulants.Interestingly,in vivo nodavirus infection resulted in alterations on the transcription of il17 receptors.While nodavirus infection led to some increments in the il17ra,il17rb,il17rc and il17rd transcripts in the susceptible European sea bass,many down-regulations were observed in the resistant gilthead seabream.Our data identify the presence and conservation of six coding IL-17R in gilthead seabream and European sea bass as well as their differential regulation in vitro and upon nodavirus infection.
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    Mucosal immune responses to Ichthyophthirius multifiliis in the ocular mucosa of rainbow trout(Oncorhynchus mykiss,Walbaum),an ancient teleost fish

    Weiguang KongGuangyi DingGaofeng ChengPeng Yang...
    266-279页
    查看更多>>摘要：The eye,as a specialized visual organ,is directly exposed to the external environment,and,therefore,it faces constant chal-lenges from external pathogenic organisms and toxins.In the ocular mucosa(OM)of mammals,mucosal-associated lymphoid tissues(MALTs)constitute the primary line of defense.However,the immune defense role of the OM remains unknown in aquatic vertebrates.To gain insights into the immune processes within the OM of teleost fish,we developed an infection model of rainbow trout(Oncorhynchus mykiss)OM using a parasite,Ichthyophthirius multifiliis(Ich).Immunofluorescence,qPCR,and H&E staining revealed that Ich successfully infiltrates the OM of rainbow trout,leading to pathological struc-tural changes,as evidenced by A&B staining.Importantly,the qPCR results indicate an up-regulation of immune-related genes following Ich infection in the OM.Moreover,transcriptome analyses were conducted to detect immune responses and impairments in eye function within the OM of rainbow trout with Ich infection.The results of the transcriptome analysis that Ich infection can cause an extensive immune response in the OM,ultimately affecting ocular function.To the best of our knowledge,our findings represent for the first time that the teleost OM could act as an invasion site for parasites and trigger a strong mucosal immune response to parasitic infection.
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    Role of marine natural products in the development of antiviral agents against SARS-CoV-2:potential and prospects

    D.P.NagahawattaN.M.LiyanageThilina U.JayawardenaH.H.A.C.K.Jayawardhana...
    280-297页
    查看更多>>摘要：A novel coronavirus,known as severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),has surfaced and caused global concern owing to its ferocity.SARS-CoV-2 is the causative agent of coronavirus disease 2019;however,it was only discovered at the end of the year and was considered a pandemic by the World Health Organization.Therefore,the develop-ment of novel potent inhibitors against SARS-CoV-2 and future outbreaks is urgently required.Numerous naturally occurring bioactive substances have been studied in the clinical setting for diverse disorders.The intricate infection and replication mechanism of SARS-CoV-2 offers diverse therapeutic drug targets for developing antiviral medicines by employing natural products that are safer than synthetic compounds.Marine natural products(MNPs)have received increased attention in the development of novel drugs owing to their high diversity and availability.Therefore,this review article investigates the infection and replication mechanisms,including the function of the SARS-CoV-2 genome and structure.Furthermore,we highlighted anti-SARS-CoV-2 therapeutic intervention efforts utilizing MNPs and predicted SARS-CoV-2 inhibitor design.
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    Metabolic relationships between marine red algae and algae-associated bacteria

    Kyung Hyun KimJeong Min KimJu Hye BaekSang Eun Jeong...
    298-314页
    查看更多>>摘要：Mutualistic interactions between marine phototrophs and associated bacteria are an important strategy for their success-ful survival in the ocean,but little is known about their metabolic relationships.Here,bacterial communities in the algal sphere(AS)and bulk solution(BS)of nine marine red algal cultures were analyzed,and Roseibium and Phycisphaera were identified significantly more abundantly in AS than in BS.The metabolic features of Roseibium RMAR6-6(isolated and genome-sequenced),Phycisphaera MAG 12(obtained by metagenomic sequencing),and a marine red alga,Porphyridium purpureum CCMP1328(from GenBank),were analyzed bioinformatically.RMAR6-6 has the genetic capability to fix nitrogen and produce B vitamins(B1,B2,B5,B6,B9,and B12),bacterioferritin,dimethylsulfoniopropionate(DMSP),and phenylacetate that may enhance algal growth,whereas MAG 12 may have a limited metabolic capability,not producing vitamins B9 and B12,DMSP,phenylacetate,and siderophores,but with the ability to produce bacitracin,possibly modulating algal microbiome.P.purpureum CCMP1328 lacks the genetic capability to fix nitrogen and produce vitamin B12,DMSP,phenylacetate,and siderophore.It was shown that the nitrogen-fixing ability of RMAR6-6 promoted the growth of P.pur-pureum,and DMSP reduced the oxidative stress of P.purpureum.The metabolic interactions between strain RMAR6-6 and P.purpureum CCMP1328 were also investigated by the transcriptomic analyses of their monoculture and co-culture.Taken together,potential metabolic relationships between Roseibium and P.purpureum were proposed.This study provides a bet-ter understanding of the metabolic relationships between marine algae and algae-associated bacteria for successful growth.
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    Context-dependent antioxidant defense system(ADS)-based stress memory in response to recurrent environmental challenges in congeneric invasive species

    Hanxi LiXuena HuangAibin Zhan
    315-330页
    查看更多>>摘要：Marine ecosystems are facing escalating environmental fluctuations owing to climate change and human activities,imposing pressures on marine species.To withstand recurring environmental challenges,marine organisms,especially benthic species lacking behavioral choices to select optimal habitats,have to utilize well-established strategies such as the antioxidant defense system(ADS)to ensure their survival.Therefore,understanding of the mechanisms governing the ADS-based response is essential for gaining insights into adaptive strategies for managing environmental challenges.Here we conducted a com-parative analysis of the physiological and transcriptional responses based on the ADS during two rounds of'hypersalinity-recovery'challenges in two model congeneric invasive ascidians,Ciona robusta and C.savignyi.Our results demonstrated that C.savignyi exhibited higher tolerance and resistance to salinity stresses at the physiological level,while C.robusta demonstrated heightened responses at the transcriptional level.We observed distinct transcriptional responses,particularly in the utilization of two superoxide dismutase(SOD)isoforms.Both Ciona species developed physiological stress memory with elevated total SOD(T-SOD)and glutathione(GSH)responses,while only C.robusta demonstrated transcriptional stress memory.The regulatory distinctions within the Nrf2-Keapl signalling pathway likely explain the formation disparity of transcriptional stress memory between both Ciona species.These findings support the'context-dependent stress memory hypothesis',emphasizing the emergence of species-specific stress memory at diverse regulatory levels in response to recurrent environmental challenges.Our results enhance our understanding of the mechanisms of environmental challenge manage-ment in marine species,particularly those related to the ADS.
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    Widespread and active piezotolerant microorganisms mediate phenolic compound degradation under high hydrostatic pressure in hadal trenches

    Hao LingYongxin LvYu ZhangNing-Yi Zhou...
    331-348页
    查看更多>>摘要：Phenolic compounds,as well as other aromatic compounds,have been reported to be abundant in hadal trenches.Although high-throughput sequencing studies have hinted at the potential of hadal microbes to degrade these compounds,direct microbiological,genetic and biochemical evidence under in situ pressures remain absent.Here,a microbial consortium and a pure culture of Pseudomonas,newly isolated from Mariana Trench sediments,efficiently degraded phenol under pressures up to 70 and 60 MPa,respectively,with concomitant increase in biomass.By analyzing a high-pressure(70 MPa)culture metatranscriptome,not only was the entire range of metabolic processes under high pressure generated,but also genes encod-ing complete phenol degradation via ortho-and meta-cleavage pathways were revealed.The isolate of Pseudomonas also contained genes encoding the complete degradation pathway.Six transcribed genes(dmpKLMNOPsed)were functionally identified to encode a multicomponent hydroxylase catalyzing the hydroxylation of phenol and its methylated derivatives by heterogeneous expression.In addition,key catabolic genes identified in the metatranscriptome of the high-pressure cultures and genomes of bacterial isolates were found to be all widely distributed in 22 published hadal microbial metagenomes.At microbiological,genetic,bioinformatics,and biochemical levels,this study found that microorganisms widely found in hadal trenches were able to effectively drive phenolic compound degradation under high hydrostatic pressures.This information will bridge a knowledge gap concerning the microbial aromatics degradation within hadal trenches.
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