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
Anastrepha fraterculus is a significant fruit fly pest in Argentina and other South American countries. Previous studies showed the key role of gut bacteria in the protection and nutrient assimilation of fruit flies, ...Anastrepha fraterculus is a significant fruit fly pest in Argentina and other South American countries. Previous studies showed the key role of gut bacteria in the protection and nutrient assimilation of fruit flies, particularly the importance of the biological fixation of nitrogen (diazotrophy). The presence of diazotrophic bacteria in A. fraterculus sp. 1 has been demonstrated through molecular, culture-independent methods. This study is aimed to characterize the composition and diversity of culturable gut bacteria of A. fraterculus sp. 1 males from different origins, and explore their metabolic roles, focusing on diazotrophic bacteria. Three male groups were studied: wild-caught (WW), lab-reared from wild larvae (WL), and lab-colony raised (LL). Gut bacteria were collected and characterized via 16S rRNA gene sequencing, with potential diazotrophs screened using selective media (SIL and NFb). Phylogenetic analysis of 16S rRNA gene mapped potential diazotrophs across the bacterial collection, while biochemical profiling and ARDRA (Amplified rDNA Restriction Analysis) were used to quickly differentiate diazotrophic bacteria. PCR testing for the nifH gene, associated with nitrogen fixation, was also performed. Bacterial diversity was highest in WW, followed by WL, and lowest in LL. In LL and WL, Enterobacter was the most frequent genus, while Klebsiella dominated in WW. Among the 20 SIL+ isolates identified, 10 came from WW, 9 from WL, and 1 from LL. One of these isolates (Enterobacter sp.) was tested as a supplement to the adult diet, without showing a beneficial effect on males pheromone calling behavior. Three isolates were also NFb+;two had the nifH gene. ARDRA was effective for rapid diazotroph discrimination. These findings highlight the potential of gut symbiotic bacteria in eco-friendly pest management strategies like the sterile insect technique (SIT). By using diazotrophic bacteria, protein requirements in artificial diets could be reduced, cutting costs and improving the affordability of SIT programs.展开更多
The ubiquitous incorporation of plastics into daily life,coupled with inefficient recycling practices,has resulted in the accumulation of millions of metric tons of plastic waste,that poses a serious threat to the Ear...The ubiquitous incorporation of plastics into daily life,coupled with inefficient recycling practices,has resulted in the accumulation of millions of metric tons of plastic waste,that poses a serious threat to the Earth's sustainability.Plastic pollution,a global problem,disrupts the ecological balance and endangers various life forms.Efforts to combat plastic pollution are underway,with a promising avenue being biological degradation facilitated by certain insects and their symbiotic gut microorganisms,particularly bacteria.This review consolidates existing knowledge on plastic degradation by insects and their influence on gut microbiota.Additionally,it delves into the potential mechanisms employed by insects in symbiosis with gut bacteria,exploring the bioconversion of waste plastics into value-added biodegradable polymers through mineralization.These insights hold significant promise for the bio-upcycling of plastic waste,opening new horizons for future biomanufacturing of high-value chemicals from plastic-derived compounds.Finally,we weigh the pros and cons of future research endeavors related to the bioprospection of plastic-degrading bacteria from underexplored insect species.We also underscore the importance of bioengineering depolymerases with novel characteristics,aiming for their application in the remediation and valorization of waste plastics.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 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
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
Conventional clear-cut timber harvest is a widespread industrial practice across the Pacific Northwest;however,information regarding how these practices impact soil microbial community structure at the regional scale ...Conventional clear-cut timber harvest is a widespread industrial practice across the Pacific Northwest;however,information regarding how these practices impact soil microbial community structure at the regional scale is limited.With evidence of consistent and substantial impact of harvest on soil microbial functional profiles across the region(despite a range of environmental conditions),the objective of this study was to determine the extent to which harvest also influences the structure of prokaryotic and fungal soil microbial communities,and how generalized these trends are throughout the geographic region.Paired soil samples were collected one year before and after harvest across nine second-growth Douglas-fir forests in the Pacific Northwest.Total community DNA was extracted from the soils,and high-throughput targeted gene sequencing of the 16 S r RNA gene for prokaryotes and the internal transcribed spacer(ITS)gene for fungi was performed.Alpha diversity was consistently and significantly higher after harvest;it was moderately so for fungal communities(+14.6%),but only marginally so for prokaryotic communities(+2.0%).Similarly,on average,a greater proportion of the variation in the community structure of fungi(20.1%)at each site was associated with forest harvest compared to that of prokaryotes(13.2%).Overall,the greatest influence of timber harvest on soil microbial communities appeared to be a relative depletion of ectomycorrhizal fungi,with a concomitant enrichment of saprotrophic fungi.Understanding the short-term responses of soil microbial communities across the region,particularly those of tree root-associated symbionts,may aid our understanding of the role soil microbial communities play in ecological succession.展开更多
Foraminifera are highly diverse and have a long evolutionary history.As key bioindicators,their phylogenetic schemes are of great importance for paleogeographic applications,but may be hard to recognize correctly.The ...Foraminifera are highly diverse and have a long evolutionary history.As key bioindicators,their phylogenetic schemes are of great importance for paleogeographic applications,but may be hard to recognize correctly.The phylogenetic relationships within the prominent genus Amphistegina are still uncertain.Molecular studies on Amphistegina have so far only focused on genetic diversity within single species and suggested a cryptic diversity that demands for further investigations.Besides molecular sequencing-based approaches,different mass spectrometry-based proteomics approaches are increasingly used to give insights into the relationship between samples and organisms,especially as these do not require reference databases.To better understand the relationship of amphisteginids and test different proteomics-based approaches we applied de novo peptide sequencing and similarity clustering to several populations of Amphistegina lobifera,A.lessonii and A.gibbosa.We also analyzed the dominant photosymbiont community to study their influence on holobiont proteomes.Our analyses indicate that especially de novo peptide sequencing allows to reconstruct the relationship among foraminiferal holobionts,although the detected separation of A.gibbosa from A.lessonii and A.lobifera may be partly influenced by their different photosymbiont types.The resulting dendrograms reflect the separation in two lineages previously suggested and provide a basis for future studies.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Funding was provided by FAO/IAEA contract 22515(CRP D42017),PICT-2019-04141,PIP-CONICET 0039PI USAL 2022-80020210100018.
文摘Anastrepha fraterculus is a significant fruit fly pest in Argentina and other South American countries. Previous studies showed the key role of gut bacteria in the protection and nutrient assimilation of fruit flies, particularly the importance of the biological fixation of nitrogen (diazotrophy). The presence of diazotrophic bacteria in A. fraterculus sp. 1 has been demonstrated through molecular, culture-independent methods. This study is aimed to characterize the composition and diversity of culturable gut bacteria of A. fraterculus sp. 1 males from different origins, and explore their metabolic roles, focusing on diazotrophic bacteria. Three male groups were studied: wild-caught (WW), lab-reared from wild larvae (WL), and lab-colony raised (LL). Gut bacteria were collected and characterized via 16S rRNA gene sequencing, with potential diazotrophs screened using selective media (SIL and NFb). Phylogenetic analysis of 16S rRNA gene mapped potential diazotrophs across the bacterial collection, while biochemical profiling and ARDRA (Amplified rDNA Restriction Analysis) were used to quickly differentiate diazotrophic bacteria. PCR testing for the nifH gene, associated with nitrogen fixation, was also performed. Bacterial diversity was highest in WW, followed by WL, and lowest in LL. In LL and WL, Enterobacter was the most frequent genus, while Klebsiella dominated in WW. Among the 20 SIL+ isolates identified, 10 came from WW, 9 from WL, and 1 from LL. One of these isolates (Enterobacter sp.) was tested as a supplement to the adult diet, without showing a beneficial effect on males pheromone calling behavior. Three isolates were also NFb+;two had the nifH gene. ARDRA was effective for rapid diazotroph discrimination. These findings highlight the potential of gut symbiotic bacteria in eco-friendly pest management strategies like the sterile insect technique (SIT). By using diazotrophic bacteria, protein requirements in artificial diets could be reduced, cutting costs and improving the affordability of SIT programs.
基金supported by the National Natural Science Foundation of China(32250410285)the National Key R&D Program of China(2023YFC3403600)Foreign Expert Program,Ministry of Science and Technology(MoST)of China(WGXZ2023020L).
文摘The ubiquitous incorporation of plastics into daily life,coupled with inefficient recycling practices,has resulted in the accumulation of millions of metric tons of plastic waste,that poses a serious threat to the Earth's sustainability.Plastic pollution,a global problem,disrupts the ecological balance and endangers various life forms.Efforts to combat plastic pollution are underway,with a promising avenue being biological degradation facilitated by certain insects and their symbiotic gut microorganisms,particularly bacteria.This review consolidates existing knowledge on plastic degradation by insects and their influence on gut microbiota.Additionally,it delves into the potential mechanisms employed by insects in symbiosis with gut bacteria,exploring the bioconversion of waste plastics into value-added biodegradable polymers through mineralization.These insights hold significant promise for the bio-upcycling of plastic waste,opening new horizons for future biomanufacturing of high-value chemicals from plastic-derived compounds.Finally,we weigh the pros and cons of future research endeavors related to the bioprospection of plastic-degrading bacteria from underexplored insect species.We also underscore the importance of bioengineering depolymerases with novel characteristics,aiming for their application in the remediation and valorization of waste plastics.
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 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.
基金supported by Weyerhaeuser Natural Resource Company.
文摘Conventional clear-cut timber harvest is a widespread industrial practice across the Pacific Northwest;however,information regarding how these practices impact soil microbial community structure at the regional scale is limited.With evidence of consistent and substantial impact of harvest on soil microbial functional profiles across the region(despite a range of environmental conditions),the objective of this study was to determine the extent to which harvest also influences the structure of prokaryotic and fungal soil microbial communities,and how generalized these trends are throughout the geographic region.Paired soil samples were collected one year before and after harvest across nine second-growth Douglas-fir forests in the Pacific Northwest.Total community DNA was extracted from the soils,and high-throughput targeted gene sequencing of the 16 S r RNA gene for prokaryotes and the internal transcribed spacer(ITS)gene for fungi was performed.Alpha diversity was consistently and significantly higher after harvest;it was moderately so for fungal communities(+14.6%),but only marginally so for prokaryotic communities(+2.0%).Similarly,on average,a greater proportion of the variation in the community structure of fungi(20.1%)at each site was associated with forest harvest compared to that of prokaryotes(13.2%).Overall,the greatest influence of timber harvest on soil microbial communities appeared to be a relative depletion of ectomycorrhizal fungi,with a concomitant enrichment of saprotrophic fungi.Understanding the short-term responses of soil microbial communities across the region,particularly those of tree root-associated symbionts,may aid our understanding of the role soil microbial communities play in ecological succession.
基金funded by the Leibniz Association(No.SAW-2014-ISAS-2)awarded to Hildegard Westphal,Albert Sickmann and Jorg Rahnenführer。
文摘Foraminifera are highly diverse and have a long evolutionary history.As key bioindicators,their phylogenetic schemes are of great importance for paleogeographic applications,but may be hard to recognize correctly.The phylogenetic relationships within the prominent genus Amphistegina are still uncertain.Molecular studies on Amphistegina have so far only focused on genetic diversity within single species and suggested a cryptic diversity that demands for further investigations.Besides molecular sequencing-based approaches,different mass spectrometry-based proteomics approaches are increasingly used to give insights into the relationship between samples and organisms,especially as these do not require reference databases.To better understand the relationship of amphisteginids and test different proteomics-based approaches we applied de novo peptide sequencing and similarity clustering to several populations of Amphistegina lobifera,A.lessonii and A.gibbosa.We also analyzed the dominant photosymbiont community to study their influence on holobiont proteomes.Our analyses indicate that especially de novo peptide sequencing allows to reconstruct the relationship among foraminiferal holobionts,although the detected separation of A.gibbosa from A.lessonii and A.lobifera may be partly influenced by their different photosymbiont types.The resulting dendrograms reflect the separation in two lineages previously suggested and provide a basis for future studies.
