To study the bioactive metabolites produced by sponge-derived uncultured symbionts, a metagenomic DNA library of the symbionts of sponge Gelliodes gracilis was constructed. The average size of DNA inserts in the libra...To study the bioactive metabolites produced by sponge-derived uncultured symbionts, a metagenomic DNA library of the symbionts of sponge Gelliodes gracilis was constructed. The average size of DNA inserts in the library was 20 kb. This library was screened for antibiotic activity using paper disc assaying. Two clones displayed the antibacterial activity against Micrococcus tetragenus. The metabolites of these two clones were analyzed through HPLC. The result showed that their metabolites were quite different from those of the host E. coli DNA and the host containing vector pHZ132. This study may present a new approach to exploring bioactive metabolites of sponge symbionts.展开更多
Marine biofouling has been regarded as a serious problem in the marine environment. The application of TBT and other heavy metal-based antifoulants has created another environmental problem. The present study explored...Marine biofouling has been regarded as a serious problem in the marine environment. The application of TBT and other heavy metal-based antifoulants has created another environmental problem. The present study explored the possible role of baterial symbionts of seagrasses Thalassia hemprichii, and Enhalus acoroides, which were successfully screened for antifouling activity against marine biofilm-forming bacteria isolated from the surrounding colonies of seagrasses. Bacterial symbionts were isolated and tested against biofilm-forming bacteria resulted in 4 bacterial symbionts capable of inhibiting the growth biofilm-forming isolates. Molecular identification based on 16S rRNA gene sequences revealed that the active bacterial symbionts belonged to the members of the genera Bacillus and Virgibacillus. Further tests of the crude extracts of the active bacterial symbionts supported the potential of these symbionts as the alternative source of environmentally friendly marine antifoulants.展开更多
The objective of this research was to improve the growth and biomass of Pterocarpus santalinus L.f.(an endangered leguminous tree)using native microbial symbionts such as arbuscular mycorrhizal fungi and Rhizobium ass...The objective of this research was to improve the growth and biomass of Pterocarpus santalinus L.f.(an endangered leguminous tree)using native microbial symbionts such as arbuscular mycorrhizal fungi and Rhizobium associated with native populations of P.santalinus.The native arbuscular mycorrhizal fungi isolated from P.santalinus soils were identifi ed as(1)Glomus fasciculatum;(2)Glomus geosporum;and Glomus aggregatum.A nitrogenfi xing microbial symbiont was isolated from the root nodules of P.santalinus and identifi ed as Rhizobium aegyptiacum by 16s rRNA gene sequencing.These microbial symbionts were inoculated individually and in combination into P.santalinus seedling roots.After 90 days,growth and biomass had improved compared with uninoculated controls.Shoot and root lengths,number of leaves,stem circumference,number of root nodules,biomass,nutrient uptake and seedling quality index were signifi cantly increased by a combined inoculation of arbuscular mycorrhizal fungi+Rhizobium aegyptiacum.It was concluded that native microbial symbionts positively infl uenced P.santalinus seedling growth which will be helpful for successful fi eld establishment.展开更多
The microbes associated with sponges play important roles in the nitrogen cycle of the coral reefs ecosystem,e.g.,nitrification,denitrification,and nitrogen fixation.However,the whole nitrogen-cycling network has rema...The microbes associated with sponges play important roles in the nitrogen cycle of the coral reefs ecosystem,e.g.,nitrification,denitrification,and nitrogen fixation.However,the whole nitrogen-cycling network has remained incomplete in any individual sponge holobiont.In this study,454 pyrosequencing of the 16S rRNA genes revealed that the sponge Spheciospongia vesparium from the South China Sea has a unique bacterial community(including 12 bacterial phyla),dominated particularly by the genus Shewanella(order Alteromonadales).A total of 10 functional genes,nifH,amoA,narG,napA,nirK,norB,nosZ,ureC,nrfA,and gltB,were detected in the microbiome of the sponge S.vesparium by gene-targeted analysis,revealing an almost complete nitrogen-cycling network in this sponge.Particularly,bacterial urea utilization and the whole denitrification pathway were highlighted.MEGAN analysis suggests that Proteobacteria(e.g.,Shewanella)and Bacteroidetes(e.g.,Bizionia)are probably involved in the nitrogen cycle in the sponge S.vesparium.展开更多
Ten marine sponge species from Rameswaram,southern India were studied for their filamentous fungal symbionts.The results suggest that fungal symbionts of marine sponges are hyperdiverse.Genera such as Acremonium,Alter...Ten marine sponge species from Rameswaram,southern India were studied for their filamentous fungal symbionts.The results suggest that fungal symbionts of marine sponges are hyperdiverse.Genera such as Acremonium,Alternaria,Aspergillus,Cladosporium,Fusarium and Penicillium were frequently isolated;no true marine fungal species were present.Species of Aspergillus were dominant and co-dominant in all the sponges screened.The fungal isolates produced antialgal,antifungal,antioxidant,antibiotic,antiinsect metabolites.A few fungi produced acetylcholinesterase inhibitors.展开更多
Symbiotic associations between microbes and insects are widespread, and it is frequent that several symbionts share the same host individual. Hence, interactions can occur between these symbionts, influencing their re...Symbiotic associations between microbes and insects are widespread, and it is frequent that several symbionts share the same host individual. Hence, interactions can occur between these symbionts, influencing their respective abundance within the host with consequences on its phenotype. Here, we investigate the effects of multiple infections in the pea aphid, Acyrthosiphon pisurn, which is the host of an obligatory and several facultative symbionts. In particular, we study the influence of a coinfection with 2 protective symbionts： Harniltonella defensa, which confers protection against parasitoids, and Rickettsiella viridis, which provides protection against fungal pathogens and predators. The effects of Hamiltonella-Rickettsiella coinfection on the respective abundance of the symbionts, host fitness and efficacy of enemy protection were studied. Asymmetrical interactions between the 2 protective symbionts have been found： when they coinfect the same aphid individuals, the Rickettsiella infection affected Hamiltonella abundance within hosts but not the Hamiltonella-mediated protective phenotype while the Hamiltonella infection negatively influences the Rickettsiella-mediated protective phenotype but not its abundance. Harboring the 2 protective symbionts also reduced the survival and fecundity of host individuals. Overall, this work highlights the effects of multiple infections on symbiont abundances and host traits that are likely to impact the maintenance of the symbiotic associations in natural habitats.展开更多
Symbionts are microorganisms residing in multicellular hosts(e.g., plants and animals), and they have been witnessed to be a rich source of diverse functional molecules. This review describes structures and biological...Symbionts are microorganisms residing in multicellular hosts(e.g., plants and animals), and they have been witnessed to be a rich source of diverse functional molecules. This review describes structures and biological activities of symbiont-derived secondary metabolites commonly referred to as "natural products", and highlights that symbiotic microbes represent an underexplored reservoir of natural products with unique scaffolds and promising significance in managing human healthcare and agricultural production.展开更多
The pea aphid Acyrthosiphon pisum hosts different facultative symbionts(FS)which provide it with various benefits,such as tolerance to heat or protection against natural enemies(e.g.,fungi,parasitoid wasps).Here,we in...The pea aphid Acyrthosiphon pisum hosts different facultative symbionts(FS)which provide it with various benefits,such as tolerance to heat or protection against natural enemies(e.g.,fungi,parasitoid wasps).Here,we investigated whether and how the presence of certain FS could affect phenoloxidase(PO)activity,a key component of insect innate immunity,under normal and stressed conditions.For this,we used clones of A.pisum of difTerent genetic backgrounds(LLOl,YR2 and T3-8V1)lacking FS or harboring one or two(Regiella insecticola,Hamiltonella defensa,Serratia symbiotica Rickettsiella viridis).Gene expression and proteomics analyses of the aphid hemolymph indicated that the two A.pisum POs,PPOl and PP02,are expressed and translated into proteins.The level of PPO genes expression as well as the amount of PPO proteins and phenoloxidase activity in the hemolymph depended on both the aphid genotype and FS species.In particular,H.defensa and R.insecticola,but not S.symbiotica-h R.viridis,caused a sharp decrease in PO activity by interfering with both transcription and translation.The microinjection of different types of stressors(yeast,Escherichia coli,latex beads)in the YR2 lines hosting different symbionts affected the survival rate of aphids and,in most cases,also decreased the expression of PPO genes after 24 h.The amount and activity of PPO proteins varied according to the type of FS and stressor,without clear corresponding changes in gene expression.These data demonstrate that the presence of certain FS influences an important component of pea aphid immunity.展开更多
We tested the recent hypothesis that the"fly factor"phenomenon(food cur-rently or previously fed on by flies attracts more flies than the same type of food kept inccessible to flies)is mediated by bacterial ...We tested the recent hypothesis that the"fly factor"phenomenon(food cur-rently or previously fed on by flies attracts more flies than the same type of food kept inccessible to flies)is mediated by bacterial symbionts deposited with feees or regur-gitated by feeding flies.We allowed laboratory-reared black blow flies,Phormia regina(Meigen),to feed and de fecate on bacterial Luria-Bertani medium solidified with agar,and isolated seven morphologically distinct bacterial colonies.We identified these us-ing matrix-assisted laser desorption/ionization mass spectrometry and sequencing of the 165 rRNA gene.In two-choice laboratory experiments,traps baited with cultures of Pro-teus mirabilis Hauser,Morganella morganii subsp.sibonii Jensen,or Serratia marcescens Bizio,captured significantly more flies than corresponding control jars baited with tryptic soy agar only.A mixture of seven bacterial strains as a trap bait was more attractive to flies than a single bacterial isolate(M.m.siboni).In a field experiment,traps baited with agar cultures of P:mirabilis and M.m siboni in combination captured significantly more flies than lraps baited with either bacterial isolate alone or the agar control.As evident by gas chromatography-mass spectrometry,the odor profiles of bacterial isolates differ,which may explain the additive effect of bacteria to the attractiveness of bacterial trap baits.As"generalist bacteria,"P mirabilis and M.m.sibonii growing on animal protein(beef liver)or plant protein(tofu)are similarly effective in attracting flies.Bacteria-derived airborne semiochemicals appear to mediate foraging by flies and to inform their feeding and oviposition decisions.展开更多
Nutritional mutualism between insects and symbiotic bacteria is widespread.The various sap-feeding whitefly species within the Bemisia tabaci complex associate with the same obligate symbiont(Portiera)and multiple sec...Nutritional mutualism between insects and symbiotic bacteria is widespread.The various sap-feeding whitefly species within the Bemisia tabaci complex associate with the same obligate symbiont(Portiera)and multiple secondary symbionts.It is often assumed that some of the symbionts residing in the whiteflies play crucial roles in the nutritional physiology of their insect hosts.Although effort has been made to understand the functions of the whitefly symbionts,the metabolic complementarity offered by these symbionts to the hosts is not yet well understood.We examined two secondary symbionts,Arsenophonus and Wolbachia,in two species of the B.tabaci whitefly complex,provisionally named as Asia II 3 and China 1.Genomic sequence analyses revealed that Arsenophonus and Wolbachia retained genes responsible for the biosynthesis of B vitamins.We then conducted transcriptomic surveys of the bacteriomes in these two species of whiteflies together with that in another species named MED of this whitefly complex previously reported.The analyses indicated that several key genes in B vitamin syntheses from the three whitefly species were identical.Our findings suggest that,similar to another secondary symbiont Hamiltonella,Arsenophonus and Wolbachia function in the nutrient provision of host whiteflies.Although phylogenetically distant species of symbionts are associated with their respective hosts,they have evolved and retained similar functions in biosynthesis of some B vitamins.Such metabolic complementarity between whiteflies and symbionts represents an important feature of their coevolution.展开更多
The entomopathogenic bacterium, Xenorhabdus nematophila was isolated from the hemolymph of Galleria mel- lonella infected with Steinernema carpocapsae. The bacterial cells and its metabolic secretions have been found ...The entomopathogenic bacterium, Xenorhabdus nematophila was isolated from the hemolymph of Galleria mel- lonella infected with Steinernema carpocapsae. The bacterial cells and its metabolic secretions have been found lethal to the Galleria larvae. Toxic secretion in broth caused 95% mortality within 4 d of application whereas the bacterial cells caused 93% mortality after 6 d. When filter and sand substrates were compared, the later one was observed as appropriate. Similarly, bacterial cells and secretion in broth were more effective at 14% moisture and 25 °C temperature treatments. Maximum insect mortality (100%) was observed when bacterial concentration of 4×106 cells/ml was used. Similarly, maximum bacterial cells in broth (95%) were penetrated into the insect body within 2 h of their application. However, when stored bacterial toxic secretion was applied to the insects its efficacy declined. On the other hand, when the same toxic secretion was dried and then dissolved either in broth or water was proved to be effective. The present study showed that the bacterium, X. nematophila or its toxic secretion can be used as an important component of integrated pest management against Galleria.展开更多
Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to lar...Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to larvae of the diamondback moth Plutella xylostella. Their application on leaves of Chinese cabbage indicated that the cells can penetrate into the insects in the absence of the nematode vector. Cell-free solutions containing metabolites were also proved as effective as bacterial cells suspension. The application of aqueous suspensions of cells of X.nematophila or solutions containing its toxic metabolites to the leaves represents a possible new strategy for controlling insect pests on foliage.展开更多
The present study aimed to predict differential enrichment of pathways and compounds in the rhizosphere microbiomes of the two wild plants(Abutilon fruticosum and Nitrosalsola vermiculata)and to predict functional shi...The present study aimed to predict differential enrichment of pathways and compounds in the rhizosphere microbiomes of the two wild plants(Abutilon fruticosum and Nitrosalsola vermiculata)and to predict functional shifts in microbiomes due to water.Amplicon sequencing of 16S rRNA region V3–V4 was done and gene-based microbial compositions were enrolled in PICRUSt to predict enriched pathways and compounds.The results indicated that“ABC transporters”and“Quorum sensing”pathways are among the highest enriched pathways in rhizosphere microbiomes of the two wild plants compared with those of the bulk soil microbiomes.The highest enriched compounds in soil microbiomes of the two wild plants included five proteins and three enzymes participating in one or more KEGG pathways.Six of these eight compounds showed higher predicted enrichment in rhizosphere soil microbiomes,while only one,namely phosphate transport system substrate-binding protein,showed higher enrichment in the surrounding bulk soil microbiomes.In terms of differentially enriched compounds due to watering,only the dual-specific aspartyl-tRNA(Asn)/glutamyl-tRNA(Gln)amidotransferase subunit A showed higher enrichment in rhizosphere soil of the two wild plants after 24 h of watering.Two of the highly enriched compounds namely branched-chain amino acid transport system ATP-binding protein and branched-chain amino acid transport system substrate-binding protein,are encoded by genes stimulated by the plant’s GABA that participates in conferring biotic and abiotic stresses in plants and improves the plant’s growth performance.The 3-Oxoacyl-[ACP]reductase,a member of the short-chain alcohol dehydrogenase/reductase(SDR)superfamily,participates in fatty acids elongation cycles and contributes to plant-microbe symbiotic relationships,while enoyl-CoA hydratase has a reverse action as it participates in“Fatty acid degradation”pathway.The methyl-accepting chemotaxis protein is an environmental signal that sense“Bacterial chemotaxis”pathway to help establishing symbiosis with plant roots by recruiting/colonizing of microbial partners(symbionts)to plant rhizosphere.This information justifies the high enrichment of compounds in plant rhizosphere.The dual-specific aspartyl-tRNA(Asn)/glutamyl-tRNA(Gln)amidotransferase subunit A contributes to the plant ability to respond to watering as it participates in attaching the correct amino acid during translation to its cognate tRNA species,while hydrolyzing incorrectly attached amino acid.These two actions reduce the influence of oxidative stress in generating misfolded proteins and in reducing fidelity of translation.展开更多
Recent researches have shown that some compounds isolated from marine organisms have striking structural similarities with the metabolites from known microorganisms. It is inferred from the researches that the symbiot...Recent researches have shown that some compounds isolated from marine organisms have striking structural similarities with the metabolites from known microorganisms. It is inferred from the researches that the symbiotic or associated marine microorganisms may be the true sources of those compounds or at least involved in the biosynthesizing process. This view has been further evidenced by the researches for many sponges and sponge-associated microorganisms. Importantly, growing evidence has highlighted that the symbiotic or associated marine microorganisms live in the microenvironment within the hosts, and they also produce secondary metabolites which are new and original in structure and unique in activity. All these suggest that the microorganisms associated with marine organisms are the sources with very high potential to be new natural bioactive agents. This article reviews briefly the research advances in the study of new bioactive metabolites from marine organisms-associated microorganisms since 2000.展开更多
From the marine environment, woodlice gradually colonized terrestrial areas benefiting from the symbiotic relationship with the bacterial community that they host. Indeed, they constitute the only group of Oniscidea s...From the marine environment, woodlice gradually colonized terrestrial areas benefiting from the symbiotic relationship with the bacterial community that they host. Indeed, they constitute the only group of Oniscidea suborder that has succeed to accomplish their lives in terrestrial even desert surfaces. Herein they play an important role in the dynamic of ecosystems and the decomposition of litter. So to enhance our understanding of the sea-land transition and other process like decomposition and digestion of detritus, we studied the bacterial community associated with 11 specimens of terrestrial isopods belonging to six species using a Culture independent approach (DGGE). Bands sequencing showed that the cosmopolitan species Porcellionides pruinosus has the most microbial diversity. Screening demonstrated the predominance of Proteobacteria followed by members from Actinobacteria, Firmicutes and Cyanobacteria phyla. In fact we detected some symbionts like Wolbachia, Mycoplasma and Spiroplasma for the first time in a terrestrial isopod species.展开更多
Wolbachia is a bacterium that infects many arthropods with horizontal or vertical transmission. The introduction and spreading of Solenopsis invicta in new areas may have influenced the acquisition of Wolbachia as thi...Wolbachia is a bacterium that infects many arthropods with horizontal or vertical transmission. The introduction and spreading of Solenopsis invicta in new areas may have influenced the acquisition of Wolbachia as this ant species spread from its South America origin to other parts of the globe. The wsp gene of Wolbachia was analyzed using the WSP Typing and a similarity analysis was conducted to analyse the sharing of the symbiont among nests of S. invicta ants. The analyses revealed the presence of two groups of Wolbachia: strain A belonging to InvA S. invicta subgroup, and the strain B belonging to Acromyrmex insinuator. The wsp gene and its hypervariable regions are shared among the Wolbachia present in different types of ants inhabiting in the New World. Wolbachia strains found in the nests of S. invicta are ant-specialist symbionts which may have spread by several means among the ant population.展开更多
Bacterial intraceUular symbiosis is very common in insects, having significant consequences in promoting the evolution of life and biodiversity. The bacterial group that has recently attracted particular attention is ...Bacterial intraceUular symbiosis is very common in insects, having significant consequences in promoting the evolution of life and biodiversity. The bacterial group that has recently attracted particular attention is Wolbachia pipientis which probably represents the most ubiquitous endosymbiont on the planet. W. pipientis is a Gram-negative obligatory intracellular and maternally transmitted a-proteobacterium, that is able to establish symbiotic associations with arthropods and nematodes. In arthropods, Wolbachia pipientis infections have been described in Arachnida, in Isopoda and mainly in Insecta. They have been reported in almost all major insect orders including Diptera, Coleoptera, Hemiptera, Hymenoptera, Orthoptera and Lepidoptera. To enhance its transmission, W. pipientis can manipulate host reproduction by inducing parthenogenesis, feminization, male killing and cytoplasmic incompatibility. Several polymerase chain reaction surveys have indicated that up to 70% of all insect species may be infected with W. pipientis. How does W. pipientis manage to get established in diverse insect host species？ How is this intracellular bacterial symbiont species so successful in escaping the host immune response？ The present review presents recent advances and ongoing scientific efforts in the field. The current body of knowledge in the field is summarized, revelations from the available genomic information are presented and as yet unanswered questions are discussed in an attempt to present a comprehensive picture of the unique ability of W. pipientis to establish symbiosis and to manipulate reproduction while evading the host＇s immune system.展开更多
The basic life cycle of Foraminifera has long been recognized as alternation between sexual and asexual generations;a common modification is several successive asexual generations.Production and release of flagellated...The basic life cycle of Foraminifera has long been recognized as alternation between sexual and asexual generations;a common modification is several successive asexual generations.Production and release of flagellated gametes also has been documented as the basic sexual-reproductive mode in extant lineages.Research on population dynamics,local spatial distributions,and biogeography of Amphistegina spp.and Heterostegina depressa have been augmented by culture studies over the past 50years,providing insights that have been widely used in paleoecological and paleoenvironmental interpretations.Hypotheses are proposed suggesting how stages in the life cycle might contribute to understanding biogeographic and evolutionary trends commonly observed in large benthic foraminifers.Recruitment of sexually-produced cryptobiotic propagules,followed by successive asexual generations(schizogeny),can potentially establish viable,locally-adapted populations within literally years,consistent with the concepts of both allopatric speciation and reticulate evolution associated with isolation and reconnection of local basins.The review concludes with the recommendation that future studies utilizing genomics,proteonomics,geochemistries,scanning technologies,and other approaches can promote greater understanding of both modern and fossil larger benthic foraminiferal lineages.展开更多
Several herbivorous insects and plant-associated microorganisms control the phytohormonal balance, thus enabling them to successfully exploit the plant by inhibiting plant defenses and withdrawing plant resources for ...Several herbivorous insects and plant-associated microorganisms control the phytohormonal balance, thus enabling them to successfully exploit the plant by inhibiting plant defenses and withdrawing plant resources for their own benefit. The leaf-mining moth Phyllonorycter blancardella modifies the cytokinin （CK） profile of mined leaf-tissues, and the insect symbiotic bacteria Wolbachia is involved in the plant manipulation to the benefit of the insect host. To gain a deeper understanding into the possible origin and dynamics of CKs, we conducted an extensive characterization of CKs in larvae and in infected apple leaves. Our results show the enhanced CK levels in mines, both on green and yellow leaves, allowing insects to control their nutritional supply under fluctuating environmental conditions. The spatial distribution of CKs within the mined leaves shows that hormone manipulation is strictly limited to the mine suggesting the absence of CK translocation from distant leaf areas toward the insect feeding site. Mass spectrometry analyses reveal that major CK types accumulating in mines and larvae are similar to what is observed for most gall-inducers, suggesting that strategies underlying the plant manipulation may be shared between herbivorous insects with distinct life histories. Results further show that CKs are detected in the highest levels in larvae, reinforcing our hypothesis that CKs accumulating in the mines originate from the insect itself. Presence of bacteria- specific methylthio-CKs is consistent with previous results suggesting that insect bacterial symbionts contribute to the observed phenotype. Our study provides key findings toward the understanding of molecular mechanisms underlying this intricate plant-insect-microbe interaction.展开更多
The wood-feeding termite Coptotermes formosanus represents a unique and impressive system for lignocellulose degradation.The highly efficient digestion of lignocellulose is achieved through symbiosis with gut symbiont...The wood-feeding termite Coptotermes formosanus represents a unique and impressive system for lignocellulose degradation.The highly efficient digestion of lignocellulose is achieved through symbiosis with gut symbionts like bacteria.Despite extensive research during the last three decades,diversity of bacterial symbionts residing in individual gut regions of the termite and their associated functions is still lacking.To this end,cellulose,xylan,and dye-decolorization bacteria residing in foregut,midgut,and hindgut regions of C.formosanus were enlisted by using enrichment and culture-dependent molecular methods.A total of 87 bacterial strains were successfully isolated from different gut regions of C.formosanus which belonged to 27 different species of 10 genera,majorly affiliated with Proteobacteria(80%)and Firmicutes(18.3%).Among the gut regions,37.9%of the total bacterial isolates were observed in the hindgut that demonstrated predominance of cellulolytic bacteria(47.6%).The majority of the xylanolytic and dye-decolorization bacteria(50%)were obtained from the foregut and midgut,respectively.Actinobacteria represented by Dietza sp.was observed in the hindgut only.Based on species richness,the highest diversity was observed in midgut and hindgut regions each of which harbored seven unique bacterial species.The members of Enterobacter,Klebsiella,and Pseudomonas were common among the gut regions.The lignocellulolytic activities of the selected potential bacteria signpost their assistance to the host for lignocellulose digestion.The overall results indicate that C.formosanus harbors diverse communities of lignocellulolytic bacteria in different regions of the gut system.These observations will significantly advance our understanding of the termite–bacteria symbiosis and their microbial ecology uniquely existed in different gut regions of C.formosanus,which may further shed a light on its potential values at termite-modeled biotechnology.展开更多
基金This work was supported by High Tech R&D Program of China(Grant Nos.2002AA628130 and 2003AA624020)the National Natural Science Foundation of China(30171102)+2 种基金the Fund for Cheung Kong Scholar from the Cheung Kong Scholar Program of Ministry of Education of Chinathe Fund from the Natural Science Foundation of Shandong Province(No.Z2001C01)the High Tech R&D Program of Shandong Province(No.0121100107).The authors would like to thank Professor Li Jinhe of Institute of 0ceanology,Chinese Academy of Sciences,for the identification of the sponge.
文摘To study the bioactive metabolites produced by sponge-derived uncultured symbionts, a metagenomic DNA library of the symbionts of sponge Gelliodes gracilis was constructed. The average size of DNA inserts in the library was 20 kb. This library was screened for antibiotic activity using paper disc assaying. Two clones displayed the antibacterial activity against Micrococcus tetragenus. The metabolites of these two clones were analyzed through HPLC. The result showed that their metabolites were quite different from those of the host E. coli DNA and the host containing vector pHZ132. This study may present a new approach to exploring bioactive metabolites of sponge symbionts.
文摘Marine biofouling has been regarded as a serious problem in the marine environment. The application of TBT and other heavy metal-based antifoulants has created another environmental problem. The present study explored the possible role of baterial symbionts of seagrasses Thalassia hemprichii, and Enhalus acoroides, which were successfully screened for antifouling activity against marine biofilm-forming bacteria isolated from the surrounding colonies of seagrasses. Bacterial symbionts were isolated and tested against biofilm-forming bacteria resulted in 4 bacterial symbionts capable of inhibiting the growth biofilm-forming isolates. Molecular identification based on 16S rRNA gene sequences revealed that the active bacterial symbionts belonged to the members of the genera Bacillus and Virgibacillus. Further tests of the crude extracts of the active bacterial symbionts supported the potential of these symbionts as the alternative source of environmentally friendly marine antifoulants.
基金a research project(No.IFGTB/NFRP 168)of the Indian Council of Forestry Research and Education,Dehra Dun.
文摘The objective of this research was to improve the growth and biomass of Pterocarpus santalinus L.f.(an endangered leguminous tree)using native microbial symbionts such as arbuscular mycorrhizal fungi and Rhizobium associated with native populations of P.santalinus.The native arbuscular mycorrhizal fungi isolated from P.santalinus soils were identifi ed as(1)Glomus fasciculatum;(2)Glomus geosporum;and Glomus aggregatum.A nitrogenfi xing microbial symbiont was isolated from the root nodules of P.santalinus and identifi ed as Rhizobium aegyptiacum by 16s rRNA gene sequencing.These microbial symbionts were inoculated individually and in combination into P.santalinus seedling roots.After 90 days,growth and biomass had improved compared with uninoculated controls.Shoot and root lengths,number of leaves,stem circumference,number of root nodules,biomass,nutrient uptake and seedling quality index were signifi cantly increased by a combined inoculation of arbuscular mycorrhizal fungi+Rhizobium aegyptiacum.It was concluded that native microbial symbionts positively infl uenced P.santalinus seedling growth which will be helpful for successful fi eld establishment.
基金Financial support from the National Natural Science Foundation of China(NSFC)(Nos.31861143020,41776138)was used to conduct this research and is greatly appreciated.
文摘The microbes associated with sponges play important roles in the nitrogen cycle of the coral reefs ecosystem,e.g.,nitrification,denitrification,and nitrogen fixation.However,the whole nitrogen-cycling network has remained incomplete in any individual sponge holobiont.In this study,454 pyrosequencing of the 16S rRNA genes revealed that the sponge Spheciospongia vesparium from the South China Sea has a unique bacterial community(including 12 bacterial phyla),dominated particularly by the genus Shewanella(order Alteromonadales).A total of 10 functional genes,nifH,amoA,narG,napA,nirK,norB,nosZ,ureC,nrfA,and gltB,were detected in the microbiome of the sponge S.vesparium by gene-targeted analysis,revealing an almost complete nitrogen-cycling network in this sponge.Particularly,bacterial urea utilization and the whole denitrification pathway were highlighted.MEGAN analysis suggests that Proteobacteria(e.g.,Shewanella)and Bacteroidetes(e.g.,Bizionia)are probably involved in the nitrogen cycle in the sponge S.vesparium.
基金TSS and MD acknowledge the financial assistance by Department of Biotechnology(BT/PR10169/AAQ/03/376/2007),New Delhi,Government of India and Dr.G.Sivaleela,Zoological Survey of India,Chennai for identifying the sponge species.
文摘Ten marine sponge species from Rameswaram,southern India were studied for their filamentous fungal symbionts.The results suggest that fungal symbionts of marine sponges are hyperdiverse.Genera such as Acremonium,Alternaria,Aspergillus,Cladosporium,Fusarium and Penicillium were frequently isolated;no true marine fungal species were present.Species of Aspergillus were dominant and co-dominant in all the sponges screened.The fungal isolates produced antialgal,antifungal,antioxidant,antibiotic,antiinsect metabolites.A few fungi produced acetylcholinesterase inhibitors.
文摘Symbiotic associations between microbes and insects are widespread, and it is frequent that several symbionts share the same host individual. Hence, interactions can occur between these symbionts, influencing their respective abundance within the host with consequences on its phenotype. Here, we investigate the effects of multiple infections in the pea aphid, Acyrthosiphon pisurn, which is the host of an obligatory and several facultative symbionts. In particular, we study the influence of a coinfection with 2 protective symbionts： Harniltonella defensa, which confers protection against parasitoids, and Rickettsiella viridis, which provides protection against fungal pathogens and predators. The effects of Hamiltonella-Rickettsiella coinfection on the respective abundance of the symbionts, host fitness and efficacy of enemy protection were studied. Asymmetrical interactions between the 2 protective symbionts have been found： when they coinfect the same aphid individuals, the Rickettsiella infection affected Hamiltonella abundance within hosts but not the Hamiltonella-mediated protective phenotype while the Hamiltonella infection negatively influences the Rickettsiella-mediated protective phenotype but not its abundance. Harboring the 2 protective symbionts also reduced the survival and fecundity of host individuals. Overall, this work highlights the effects of multiple infections on symbiont abundances and host traits that are likely to impact the maintenance of the symbiotic associations in natural habitats.
基金supported by the National High Technology Research and Development Program of China(2013AA092901)the National Natural Science Foundation of China(81121062,21132004,81421091)
文摘Symbionts are microorganisms residing in multicellular hosts(e.g., plants and animals), and they have been witnessed to be a rich source of diverse functional molecules. This review describes structures and biological activities of symbiont-derived secondary metabolites commonly referred to as "natural products", and highlights that symbiotic microbes represent an underexplored reservoir of natural products with unique scaffolds and promising significance in managing human healthcare and agricultural production.
基金funded by the China Scholarship Council(grant number:201506300039)supported by the French Government through the "Investments for the Future" programs LABEX SIGNALIFE ANR-ll-LABX-0028-01 and IDEX UCAJedi ANR-15-IDEX-01.
文摘The pea aphid Acyrthosiphon pisum hosts different facultative symbionts(FS)which provide it with various benefits,such as tolerance to heat or protection against natural enemies(e.g.,fungi,parasitoid wasps).Here,we investigated whether and how the presence of certain FS could affect phenoloxidase(PO)activity,a key component of insect innate immunity,under normal and stressed conditions.For this,we used clones of A.pisum of difTerent genetic backgrounds(LLOl,YR2 and T3-8V1)lacking FS or harboring one or two(Regiella insecticola,Hamiltonella defensa,Serratia symbiotica Rickettsiella viridis).Gene expression and proteomics analyses of the aphid hemolymph indicated that the two A.pisum POs,PPOl and PP02,are expressed and translated into proteins.The level of PPO genes expression as well as the amount of PPO proteins and phenoloxidase activity in the hemolymph depended on both the aphid genotype and FS species.In particular,H.defensa and R.insecticola,but not S.symbiotica-h R.viridis,caused a sharp decrease in PO activity by interfering with both transcription and translation.The microinjection of different types of stressors(yeast,Escherichia coli,latex beads)in the YR2 lines hosting different symbionts affected the survival rate of aphids and,in most cases,also decreased the expression of PPO genes after 24 h.The amount and activity of PPO proteins varied according to the type of FS and stressor,without clear corresponding changes in gene expression.These data demonstrate that the presence of certain FS influences an important component of pea aphid immunity.
文摘We tested the recent hypothesis that the"fly factor"phenomenon(food cur-rently or previously fed on by flies attracts more flies than the same type of food kept inccessible to flies)is mediated by bacterial symbionts deposited with feees or regur-gitated by feeding flies.We allowed laboratory-reared black blow flies,Phormia regina(Meigen),to feed and de fecate on bacterial Luria-Bertani medium solidified with agar,and isolated seven morphologically distinct bacterial colonies.We identified these us-ing matrix-assisted laser desorption/ionization mass spectrometry and sequencing of the 165 rRNA gene.In two-choice laboratory experiments,traps baited with cultures of Pro-teus mirabilis Hauser,Morganella morganii subsp.sibonii Jensen,or Serratia marcescens Bizio,captured significantly more flies than corresponding control jars baited with tryptic soy agar only.A mixture of seven bacterial strains as a trap bait was more attractive to flies than a single bacterial isolate(M.m.siboni).In a field experiment,traps baited with agar cultures of P:mirabilis and M.m siboni in combination captured significantly more flies than lraps baited with either bacterial isolate alone or the agar control.As evident by gas chromatography-mass spectrometry,the odor profiles of bacterial isolates differ,which may explain the additive effect of bacteria to the attractiveness of bacterial trap baits.As"generalist bacteria,"P mirabilis and M.m.sibonii growing on animal protein(beef liver)or plant protein(tofu)are similarly effective in attracting flies.Bacteria-derived airborne semiochemicals appear to mediate foraging by flies and to inform their feeding and oviposition decisions.
基金supported by the National Natural Science Foundation of China(Project no.:31772173).
文摘Nutritional mutualism between insects and symbiotic bacteria is widespread.The various sap-feeding whitefly species within the Bemisia tabaci complex associate with the same obligate symbiont(Portiera)and multiple secondary symbionts.It is often assumed that some of the symbionts residing in the whiteflies play crucial roles in the nutritional physiology of their insect hosts.Although effort has been made to understand the functions of the whitefly symbionts,the metabolic complementarity offered by these symbionts to the hosts is not yet well understood.We examined two secondary symbionts,Arsenophonus and Wolbachia,in two species of the B.tabaci whitefly complex,provisionally named as Asia II 3 and China 1.Genomic sequence analyses revealed that Arsenophonus and Wolbachia retained genes responsible for the biosynthesis of B vitamins.We then conducted transcriptomic surveys of the bacteriomes in these two species of whiteflies together with that in another species named MED of this whitefly complex previously reported.The analyses indicated that several key genes in B vitamin syntheses from the three whitefly species were identical.Our findings suggest that,similar to another secondary symbiont Hamiltonella,Arsenophonus and Wolbachia function in the nutrient provision of host whiteflies.Although phylogenetically distant species of symbionts are associated with their respective hosts,they have evolved and retained similar functions in biosynthesis of some B vitamins.Such metabolic complementarity between whiteflies and symbionts represents an important feature of their coevolution.
文摘The entomopathogenic bacterium, Xenorhabdus nematophila was isolated from the hemolymph of Galleria mel- lonella infected with Steinernema carpocapsae. The bacterial cells and its metabolic secretions have been found lethal to the Galleria larvae. Toxic secretion in broth caused 95% mortality within 4 d of application whereas the bacterial cells caused 93% mortality after 6 d. When filter and sand substrates were compared, the later one was observed as appropriate. Similarly, bacterial cells and secretion in broth were more effective at 14% moisture and 25 °C temperature treatments. Maximum insect mortality (100%) was observed when bacterial concentration of 4×106 cells/ml was used. Similarly, maximum bacterial cells in broth (95%) were penetrated into the insect body within 2 h of their application. However, when stored bacterial toxic secretion was applied to the insects its efficacy declined. On the other hand, when the same toxic secretion was dried and then dissolved either in broth or water was proved to be effective. The present study showed that the bacterium, X. nematophila or its toxic secretion can be used as an important component of integrated pest management against Galleria.
文摘Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to larvae of the diamondback moth Plutella xylostella. Their application on leaves of Chinese cabbage indicated that the cells can penetrate into the insects in the absence of the nematode vector. Cell-free solutions containing metabolites were also proved as effective as bacterial cells suspension. The application of aqueous suspensions of cells of X.nematophila or solutions containing its toxic metabolites to the leaves represents a possible new strategy for controlling insect pests on foliage.
文摘The present study aimed to predict differential enrichment of pathways and compounds in the rhizosphere microbiomes of the two wild plants(Abutilon fruticosum and Nitrosalsola vermiculata)and to predict functional shifts in microbiomes due to water.Amplicon sequencing of 16S rRNA region V3–V4 was done and gene-based microbial compositions were enrolled in PICRUSt to predict enriched pathways and compounds.The results indicated that“ABC transporters”and“Quorum sensing”pathways are among the highest enriched pathways in rhizosphere microbiomes of the two wild plants compared with those of the bulk soil microbiomes.The highest enriched compounds in soil microbiomes of the two wild plants included five proteins and three enzymes participating in one or more KEGG pathways.Six of these eight compounds showed higher predicted enrichment in rhizosphere soil microbiomes,while only one,namely phosphate transport system substrate-binding protein,showed higher enrichment in the surrounding bulk soil microbiomes.In terms of differentially enriched compounds due to watering,only the dual-specific aspartyl-tRNA(Asn)/glutamyl-tRNA(Gln)amidotransferase subunit A showed higher enrichment in rhizosphere soil of the two wild plants after 24 h of watering.Two of the highly enriched compounds namely branched-chain amino acid transport system ATP-binding protein and branched-chain amino acid transport system substrate-binding protein,are encoded by genes stimulated by the plant’s GABA that participates in conferring biotic and abiotic stresses in plants and improves the plant’s growth performance.The 3-Oxoacyl-[ACP]reductase,a member of the short-chain alcohol dehydrogenase/reductase(SDR)superfamily,participates in fatty acids elongation cycles and contributes to plant-microbe symbiotic relationships,while enoyl-CoA hydratase has a reverse action as it participates in“Fatty acid degradation”pathway.The methyl-accepting chemotaxis protein is an environmental signal that sense“Bacterial chemotaxis”pathway to help establishing symbiosis with plant roots by recruiting/colonizing of microbial partners(symbionts)to plant rhizosphere.This information justifies the high enrichment of compounds in plant rhizosphere.The dual-specific aspartyl-tRNA(Asn)/glutamyl-tRNA(Gln)amidotransferase subunit A contributes to the plant ability to respond to watering as it participates in attaching the correct amino acid during translation to its cognate tRNA species,while hydrolyzing incorrectly attached amino acid.These two actions reduce the influence of oxidative stress in generating misfolded proteins and in reducing fidelity of translation.
基金supported by the National Natural Science Foundation of China(No.39825126)the Cheung Kong Scholar from the Cheung Kong Scholars Program of Ministry of Education of China+2 种基金the Hi-Tech Research and Development Program of China(Nos.2002AA628130 and 2003AA624020)the Natural Science Foundation of Shandong Province(No.Z2001C01)the High Technology Research and Development Program of Shandong Province(No.0121100107).
文摘Recent researches have shown that some compounds isolated from marine organisms have striking structural similarities with the metabolites from known microorganisms. It is inferred from the researches that the symbiotic or associated marine microorganisms may be the true sources of those compounds or at least involved in the biosynthesizing process. This view has been further evidenced by the researches for many sponges and sponge-associated microorganisms. Importantly, growing evidence has highlighted that the symbiotic or associated marine microorganisms live in the microenvironment within the hosts, and they also produce secondary metabolites which are new and original in structure and unique in activity. All these suggest that the microorganisms associated with marine organisms are the sources with very high potential to be new natural bioactive agents. This article reviews briefly the research advances in the study of new bioactive metabolites from marine organisms-associated microorganisms since 2000.
文摘From the marine environment, woodlice gradually colonized terrestrial areas benefiting from the symbiotic relationship with the bacterial community that they host. Indeed, they constitute the only group of Oniscidea suborder that has succeed to accomplish their lives in terrestrial even desert surfaces. Herein they play an important role in the dynamic of ecosystems and the decomposition of litter. So to enhance our understanding of the sea-land transition and other process like decomposition and digestion of detritus, we studied the bacterial community associated with 11 specimens of terrestrial isopods belonging to six species using a Culture independent approach (DGGE). Bands sequencing showed that the cosmopolitan species Porcellionides pruinosus has the most microbial diversity. Screening demonstrated the predominance of Proteobacteria followed by members from Actinobacteria, Firmicutes and Cyanobacteria phyla. In fact we detected some symbionts like Wolbachia, Mycoplasma and Spiroplasma for the first time in a terrestrial isopod species.
基金the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior(CAPES)for the financial support to the first author
文摘Wolbachia is a bacterium that infects many arthropods with horizontal or vertical transmission. The introduction and spreading of Solenopsis invicta in new areas may have influenced the acquisition of Wolbachia as this ant species spread from its South America origin to other parts of the globe. The wsp gene of Wolbachia was analyzed using the WSP Typing and a similarity analysis was conducted to analyse the sharing of the symbiont among nests of S. invicta ants. The analyses revealed the presence of two groups of Wolbachia: strain A belonging to InvA S. invicta subgroup, and the strain B belonging to Acromyrmex insinuator. The wsp gene and its hypervariable regions are shared among the Wolbachia present in different types of ants inhabiting in the New World. Wolbachia strains found in the nests of S. invicta are ant-specialist symbionts which may have spread by several means among the ant population.
文摘Bacterial intraceUular symbiosis is very common in insects, having significant consequences in promoting the evolution of life and biodiversity. The bacterial group that has recently attracted particular attention is Wolbachia pipientis which probably represents the most ubiquitous endosymbiont on the planet. W. pipientis is a Gram-negative obligatory intracellular and maternally transmitted a-proteobacterium, that is able to establish symbiotic associations with arthropods and nematodes. In arthropods, Wolbachia pipientis infections have been described in Arachnida, in Isopoda and mainly in Insecta. They have been reported in almost all major insect orders including Diptera, Coleoptera, Hemiptera, Hymenoptera, Orthoptera and Lepidoptera. To enhance its transmission, W. pipientis can manipulate host reproduction by inducing parthenogenesis, feminization, male killing and cytoplasmic incompatibility. Several polymerase chain reaction surveys have indicated that up to 70% of all insect species may be infected with W. pipientis. How does W. pipientis manage to get established in diverse insect host species？ How is this intracellular bacterial symbiont species so successful in escaping the host immune response？ The present review presents recent advances and ongoing scientific efforts in the field. The current body of knowledge in the field is summarized, revelations from the available genomic information are presented and as yet unanswered questions are discussed in an attempt to present a comprehensive picture of the unique ability of W. pipientis to establish symbiosis and to manipulate reproduction while evading the host＇s immune system.
文摘The basic life cycle of Foraminifera has long been recognized as alternation between sexual and asexual generations;a common modification is several successive asexual generations.Production and release of flagellated gametes also has been documented as the basic sexual-reproductive mode in extant lineages.Research on population dynamics,local spatial distributions,and biogeography of Amphistegina spp.and Heterostegina depressa have been augmented by culture studies over the past 50years,providing insights that have been widely used in paleoecological and paleoenvironmental interpretations.Hypotheses are proposed suggesting how stages in the life cycle might contribute to understanding biogeographic and evolutionary trends commonly observed in large benthic foraminifers.Recruitment of sexually-produced cryptobiotic propagules,followed by successive asexual generations(schizogeny),can potentially establish viable,locally-adapted populations within literally years,consistent with the concepts of both allopatric speciation and reticulate evolution associated with isolation and reconnection of local basins.The review concludes with the recommendation that future studies utilizing genomics,proteonomics,geochemistries,scanning technologies,and other approaches can promote greater understanding of both modern and fossil larger benthic foraminiferal lineages.
文摘Several herbivorous insects and plant-associated microorganisms control the phytohormonal balance, thus enabling them to successfully exploit the plant by inhibiting plant defenses and withdrawing plant resources for their own benefit. The leaf-mining moth Phyllonorycter blancardella modifies the cytokinin （CK） profile of mined leaf-tissues, and the insect symbiotic bacteria Wolbachia is involved in the plant manipulation to the benefit of the insect host. To gain a deeper understanding into the possible origin and dynamics of CKs, we conducted an extensive characterization of CKs in larvae and in infected apple leaves. Our results show the enhanced CK levels in mines, both on green and yellow leaves, allowing insects to control their nutritional supply under fluctuating environmental conditions. The spatial distribution of CKs within the mined leaves shows that hormone manipulation is strictly limited to the mine suggesting the absence of CK translocation from distant leaf areas toward the insect feeding site. Mass spectrometry analyses reveal that major CK types accumulating in mines and larvae are similar to what is observed for most gall-inducers, suggesting that strategies underlying the plant manipulation may be shared between herbivorous insects with distinct life histories. Results further show that CKs are detected in the highest levels in larvae, reinforcing our hypothesis that CKs accumulating in the mines originate from the insect itself. Presence of bacteria- specific methylthio-CKs is consistent with previous results suggesting that insect bacterial symbionts contribute to the observed phenotype. Our study provides key findings toward the understanding of molecular mechanisms underlying this intricate plant-insect-microbe interaction.
基金supported by the National Nat-ural Science Foundation of China(31900367,31772529)the National Key R&D Program of China(2018YFE0107100)+1 种基金Priority of Academic Program Development of Jiangsu Higher Education Institutions(PAPD 4013000011)supported in part by the Grant-in-Aid Startup Foundation(10JDG127)of Jiangsu University,China.
文摘The wood-feeding termite Coptotermes formosanus represents a unique and impressive system for lignocellulose degradation.The highly efficient digestion of lignocellulose is achieved through symbiosis with gut symbionts like bacteria.Despite extensive research during the last three decades,diversity of bacterial symbionts residing in individual gut regions of the termite and their associated functions is still lacking.To this end,cellulose,xylan,and dye-decolorization bacteria residing in foregut,midgut,and hindgut regions of C.formosanus were enlisted by using enrichment and culture-dependent molecular methods.A total of 87 bacterial strains were successfully isolated from different gut regions of C.formosanus which belonged to 27 different species of 10 genera,majorly affiliated with Proteobacteria(80%)and Firmicutes(18.3%).Among the gut regions,37.9%of the total bacterial isolates were observed in the hindgut that demonstrated predominance of cellulolytic bacteria(47.6%).The majority of the xylanolytic and dye-decolorization bacteria(50%)were obtained from the foregut and midgut,respectively.Actinobacteria represented by Dietza sp.was observed in the hindgut only.Based on species richness,the highest diversity was observed in midgut and hindgut regions each of which harbored seven unique bacterial species.The members of Enterobacter,Klebsiella,and Pseudomonas were common among the gut regions.The lignocellulolytic activities of the selected potential bacteria signpost their assistance to the host for lignocellulose digestion.The overall results indicate that C.formosanus harbors diverse communities of lignocellulolytic bacteria in different regions of the gut system.These observations will significantly advance our understanding of the termite–bacteria symbiosis and their microbial ecology uniquely existed in different gut regions of C.formosanus,which may further shed a light on its potential values at termite-modeled biotechnology.
