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1.
Appl Environ Microbiol ; 85(22)2019 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-31492669

RESUMO

In deep-sea hydrothermal vent environments, sulfur-oxidizing bacteria belonging to the clade SUP05 are crucial symbionts of invertebrate animals. Marine viruses, as the most abundant biological entities in the ocean, play essential roles in regulating the sulfur metabolism of the SUP05 bacteria. To date, vent sponge-associated SUP05 and their phages have not been well documented. The current study analyzed microbiomes of Haplosclerida sponges from hydrothermal vents in the Okinawa Trough and recovered the dominant SUP05 genome, designated VS-SUP05. Phylogenetic analysis showed that VS-SUP05 was closely related to endosymbiotic SUP05 strains from mussels living in deep-sea hydrothermal vent fields. Homology and metabolic pathway comparisons against free-living and symbiotic SUP05 strains revealed that the VS-SUP05 genome shared many features with the deep-sea mussel symbionts. Supporting a potentially symbiotic lifestyle, the VS-SUP05 genome contained genes involved in the synthesis of essential amino acids and cofactors that are desired by the host. Analysis of sponge-associated viral sequences revealed putative VS-SUP05 phages, all of which were double-stranded viruses belonging to the families Myoviridae, Siphoviridae, Podoviridae, and Microviridae Among the phage sequences, one contig contained metabolic genes (iscR, iscS, and iscU) involved in iron-sulfur cluster formation. Interestingly, genome sequence comparison revealed horizontal transfer of the iscS gene among phages, VS-SUP05, and other symbiotic SUP05 strains, indicating an interaction between marine phages and SUP05 symbionts. Overall, our findings confirm the presence of SUP05 bacteria and their phages in sponges from deep-sea vents and imply a beneficial interaction that allows adaptation of the host sponge to the hydrothermal vent environment.IMPORTANCE Chemosynthetic SUP05 bacteria dominate the microbial communities of deep-sea hydrothermal vents around the world, SUP05 bacteria utilize reduced chemical compounds in vent fluids and commonly form symbioses with invertebrate organisms. This symbiotic relationship could be key to adapting to such unique and extreme environments. Viruses are the most abundant biological entities on the planet and have been identified in hydrothermal vent environments. However, their interactions with the symbiotic microbes of the SUP05 clade, along with their role in the symbiotic system, remain unclear. Here, using metagenomic sequence-based analyses, we determined that bacteriophages may support metabolism in SUP05 bacteria and play a role in the sponge-associated symbiosis system in hydrothermal vent environments.


Assuntos
Bacteriófagos/classificação , Fontes Hidrotermais , Poríferos/microbiologia , Poríferos/virologia , Bactérias Redutoras de Enxofre/virologia , Simbiose , Animais , Bacteriófagos/metabolismo , Genoma Bacteriano , Redes e Vias Metabólicas , Metagenômica , Microbiota , Oxirredução , Filogenia , RNA Ribossômico 16S/genética , Enxofre/metabolismo
2.
Appl Environ Microbiol ; 85(1)2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30366990

RESUMO

Hadal environments sustain diverse microorganisms. A few studies have investigated hadal microbial communities consisting of free-living or particle-associated bacteria and archaea. However, animal-associated microbial communities in hadal environments remain largely unexplored, and comparative analyses of animal gut microbiota between two isolated hadal environments have never been done so far. In the present study, 228 Gb of gut metagenomes of the giant amphipod Hirondellea gigas from two hadal trenches, the Mariana Trench and Japan Trench, were sequenced and analyzed. Taxonomic analysis identified 49 microbial genera commonly shared by the gut microbiota of the two H. gigas populations. However, the results of statistical analysis, in congruency with the alpha and beta diversity analyses, revealed significant differences in gut microbial composition across the two trenches. Abundance variation of Psychromonas, Propionibacterium, and Pseudoalteromonas species was observed. Microbial cooccurrence was demonstrated for microbes that were overrepresented in the Mariana trench. Comparison of functional potential showed that the percentage of carbohydrate metabolic genes among the total microbial genes was significantly higher in the guts of H. gigas specimens from the Mariana Trench. Integrating carbon input information and geological characters of the two hadal trenches, we propose that the differences in the community structure might be due to several selective factors, such as environmental variations and microbial interactions.IMPORTANCE The taxonomic composition and functional potential of animal gut microbiota in deep-sea environments remain largely unknown. Here, by performing comparative metagenomics, we suggest that the gut microbial compositions of two Hirondellea gigas populations from the Mariana Trench and the Japan Trench have undergone significant divergence. Through analyses of functional potentials and microbe-microbe correlations, our findings shed light on the contributions of animal gut microbiota to host adaptation to hadal environments.


Assuntos
Anfípodes/microbiologia , Archaea/fisiologia , Fenômenos Fisiológicos Bacterianos , Microbioma Gastrointestinal/fisiologia , Animais , Archaea/classificação , Bactérias/classificação , Fontes Hidrotermais
3.
Sci Rep ; 8(1): 14142, 2018 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-30237562

RESUMO

Mammalian gastrointestinal (GI) tract microbial communities are critical for host health. However, the microbiota along the GI tract in cetaceans has not been well characterized compared to other animals. In this study, the bacteria and fungi present in the stomach, foregut, hindgut and feces, of East Asian finless porpoises (Neophocaena asiaeorientalis sunameri, EAFPs) were characterized using high-throughput sequencing analysis. The bacterial and fungal diversity and richness in the stomach, hindgut and fecal samples tended to be higher than those in the foregut. Bacterial taxonomic compositions found in the hindgut and feces were different from those seen in the stomach and foregut. A greater proportion of strict anaerobic bacteria including Clostridia, Fusobacteria, and Ruminococcaceae were found in the hindgut and fecal samples. The fungal communities present in stomach samples differed from those detected in other regions to some extent. Zygomycota and Neocallimastigomycota were more predominant in the stomach. Some potential pathogens, such as Helicobacter spp. and Vibrio spp., were commonly present along the GI tract. Our study confirms that the fecal microbiota can represent the whole GI tract to some extent because of their relatively higher microbial diversity and presence of potential pathogens. Our study provides the first comprehensive characterization of the EAFPs GI microbiota, expanding on the current knowledge about the bacterial diversity in the GI tract of cetaceans. In addition, this is the first study characterizing the fungal diversity of any species of porpoise.


Assuntos
Trato Gastrointestinal/microbiologia , Microbiota/fisiologia , Toninhas/microbiologia , Animais , Fezes/microbiologia , Sequenciamento de Nucleotídeos em Larga Escala
4.
Appl Microbiol Biotechnol ; 102(11): 4963-4973, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29637293

RESUMO

Coral reef ecosystems have great economic, social, and ecological value. The ecological success of coral reef ecosystems critically depends on coral-algal symbiosis and coral-prokaryotic partnership. However, seasonal changes underlying these relationships in subtropical hard corals of Hong Kong are poorly studied. Here, we compared the community changes of algal symbionts and prokaryotic partners in Platygyra carnosa and Galaxea fascicularis from Hong Kong collected at two seasonal time points of winter and summer via massively parallel sequencing of genetic markers and multivariate analysis. The results indicated that algal symbionts showed no significant changes between the two seasonal time points but prokaryotic partners changed substantially. Prokaryotic partners putatively involved in photosynthesis, nitrogen fixation, and sulfur oxidation increased significantly from winter to summer, while prokaryotic partners potentially associated with chemosynthesis, ammonia oxidation, and nitrite oxidation decreased significantly from winter to summer. Dissolved oxygen and pH served as the main contributors influencing prokaryotic partners in winter, while temperature, turbidity, and salinity played a dominant role in shaping prokaryotic partners in summer. The findings of the present study suggest that season structures prokaryotic partners but not algal symbionts in subtropical hard corals.


Assuntos
Antozoários/microbiologia , Estações do Ano , Simbiose , Animais , Recifes de Corais , Hong Kong
5.
mSystems ; 3(3)2018.
Artigo em Inglês | MEDLINE | ID: mdl-29657971

RESUMO

Amphipods are the dominant scavenging metazoan species in the Mariana Trench, the deepest known point in Earth's oceans. Here the gut microbiota of the amphipod Hirondellea gigas collected from the Challenger and Sirena Deeps of the Mariana Trench were investigated. The 11 amphipod individuals included for analyses were dominated by Psychromonas, of which a nearly complete genome was successfully recovered (designated CDP1). Compared with previously reported free-living Psychromonas strains, CDP1 has a highly reduced genome. Genome alignment showed deletion of the trimethylamine N-oxide (TMAO) reducing gene cluster in CDP1, suggesting that the "piezolyte" function of TMAO is more important than its function in respiration, which may lead to TMAO accumulation. In terms of nutrient utilization, the bacterium retains its central carbohydrate metabolism but lacks most of the extended carbohydrate utilization pathways, suggesting the confinement of Psychromonas to the host gut and sequestration from more variable environmental conditions. Moreover, CDP1 contains a complete formate hydrogenlyase complex, which might be involved in energy production. The genomic analyses imply that CDP1 may have developed adaptive strategies for a lifestyle within the gut of the hadal amphipod H. gigas. IMPORTANCE As a unique but poorly investigated habitat within marine ecosystems, hadal trenches have received interest in recent years. This study explores the gut microbial composition and function in hadal amphipods, which are among the dominant carrion feeders in hadal habitats. Further analyses of a dominant strain revealed genomic features that may contribute to its adaptation to the amphipod gut environment. Our findings provide new insights into animal-associated bacteria in the hadal biosphere.

6.
Sci Rep ; 8(1): 2428, 2018 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-29402898

RESUMO

Coral reefs are significant ecosystems. The ecological success of coral reefs relies on not only coral-algal symbiosis but also coral-microbial partnership. However, microbiome assemblages in the South China Sea corals remain largely unexplored. Here, we compared the microbiome assemblages of reef-building corals Galaxea (G. fascicularis) and Montipora (M. venosa, M. peltiformis, M. monasteriata) collected from five different locations in the South China Sea using massively-parallel sequencing of 16S rRNA gene and multivariate analysis. The results indicated that microbiome assemblages for each coral species were unique regardless of location and were different from the corresponding seawater. Host type appeared to drive the coral microbiome assemblages rather than location and seawater. Network analysis was employed to explore coral microbiome co-occurrence patterns, which revealed 61 and 80 co-occurring microbial species assembling the Galaxea and Montipora microbiomes, respectively. Most of these co-occurring microbial species were commonly found in corals and were inferred to play potential roles in host nutrient metabolism; carbon, nitrogen, sulfur cycles; host detoxification; and climate change. These findings suggest that the co-occurring microbial species explored might be essential to maintain the critical coral-microbial partnership. The present study provides new insights into coral microbiome assemblages in the South China Sea.


Assuntos
Antozoários/microbiologia , Archaea/genética , Bactérias/genética , Metagenoma , Microbiota/genética , Simbiose/fisiologia , Animais , Antozoários/fisiologia , Archaea/classificação , Archaea/isolamento & purificação , Bactérias/classificação , Bactérias/isolamento & purificação , Ciclo do Carbono/fisiologia , China , Recifes de Corais , Sequenciamento de Nucleotídeos em Larga Escala , Ciclo do Nitrogênio/fisiologia , Oceano Pacífico , RNA Ribossômico 16S/genética , Água do Mar/microbiologia , Enxofre/fisiologia
7.
Mar Drugs ; 15(9)2017 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28862674

RESUMO

The aim of this research is to explore the biological and chemical diversity of bacteria associated with a marine flatworm Paraplanocera sp., and to discover the bioactive metabolites from culturable strains. A total of 141 strains of bacteria including 45 strains of actinomycetes and 96 strains of other bacteria were isolated, identified and fermented on a small scale. Bioactive screening (antibacterial and cytotoxic activities) and chemical screening (ultra-performance liquid chromatography-mass spectrometry (UPLC-MS)) yielded several target bacterial strains. Among these strains, the ethyl acetate (EA) crude extract of Streptomyces sp. XY-FW47 fermentation broth showed strong antibacterial activity against methicillin-resistant Staphylococcus aureus ATCC43300 (MRSA ATCC43300) and potent cytotoxic effects on HeLa cells. The UPLC-MS spectral analysis of the crude extract indicated that the strain XY-FW47 could produce a series of geldanamycins (GMs). One new geldanamycin (GM) analog, 4,5-dihydro-17-O-demethylgeldanamycin (1), and three known GMs (2-4) were obtained. All of these compounds were tested for antibacterial, cytotoxic, and antifungal activities, yet only GM (3) showed potent cytotoxic (HeLa cells, EC50 = 1.12 µg/mL) and antifungal (Setosphaeria turcica MIC = 2.40 µg/mL) activities. Their structure-activity relationship (SAR) was also preliminarily discussed in this study.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Platelmintos/microbiologia , Actinobacteria/química , Actinobacteria/genética , Animais , Benzoquinonas/metabolismo , Sedimentos Geológicos/microbiologia , Células HeLa , Humanos , Lactamas Macrocíclicas/metabolismo , Biologia Marinha , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Streptomyces/química , Relação Estrutura-Atividade
8.
Sci Rep ; 7(1): 9320, 2017 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-28839161

RESUMO

Coral reefs are ecologically significant habitats. Coral-algal symbiosis confers ecological success on coral reefs and coral-microbial symbiosis is also vital to coral reefs. However, current understanding of coral-microbial symbiosis on a genomic scale is largely unknown. Here we report a potential microbial symbiont in corals revealed by metagenomics-based genomic study. Microbial cells in coral were enriched for metagenomic analysis and a high-quality draft genome of "Candidatus Prosthecochloris korallensis" was recovered by metagenome assembly and genome binning. Phylogenetic analysis shows "Ca. P. korallensis" belongs to the Prosthecochloris clade and is clustered with two Prosthecochloris clones derived from Caribbean corals. Genomic analysis reveals "Ca. P. korallensis" has potentially important ecological functions including anoxygenic photosynthesis, carbon fixation via the reductive tricarboxylic acid (rTCA) cycle, nitrogen fixation, and sulfur oxidization. Core metabolic pathway analysis suggests "Ca. P. korallensis" is a green sulfur bacterium capable of photoautotrophy or mixotrophy. Potential host-microbial interaction reveals a symbiotic relationship: "Ca. P. korallensis" might provide organic and nitrogenous nutrients to its host and detoxify sulfide for the host; the host might provide "Ca. P. korallensis" with an anaerobic environment for survival, carbon dioxide and acetate for growth, and hydrogen sulfide as an electron donor for photosynthesis.


Assuntos
Antozoários/microbiologia , Chlorobi/classificação , Chlorobi/fisiologia , Simbiose , Animais , Região do Caribe , Chlorobi/genética , Análise por Conglomerados , Biologia Computacional , Redes e Vias Metabólicas/genética , Metagenômica , Filogenia , Sequenciamento Completo do Genoma
9.
mSystems ; 2(2)2017.
Artigo em Inglês | MEDLINE | ID: mdl-28345060

RESUMO

As the most ancient metazoan, sponges have established close relationships with particular microbial symbionts. However, the characteristics and physiology of thioautotrophic symbionts in deep-sea sponges are largely unknown. Using a tailored "differential coverage binning" method on 22-Gb metagenomic sequences, we recovered the nearly complete genome of a sulfur-oxidizing bacterium (SOB) that dominates the microbiota of the cold seep sponge Suberites sp. Phylogenetic analyses suggested that this bacterium (an unclassified gammaproteobacterium termed "Gsub") may represent a new deep-sea SOB group. Microscopic observations suggest that Gsub is probably an extracellular symbiont. Gsub has complete sulfide oxidation and carbon fixation pathways, suggesting a chemoautotrophic lifestyle. Comparative genomics with other sponge-associated SOB and free-living SOB revealed significant genome reduction in Gsub, characterized by the loss of genes for carbohydrate metabolism, motility, DNA repair, and osmotic stress response. Intriguingly, this scenario of genome reduction is highly similar to those of the endosymbionts in deep-sea clams. However, Gsub has retained genes for phage defense and protein secretion, with the latter potentially playing a role in interactions with the sponge host. In addition, we recovered the genome of an ammonia-oxidizing archaeon (AOA), which may carry out ammonia oxidation and carbon fixation within the sponge body. IMPORTANCE Sponges and their symbionts are important players in the biogeochemical cycles of marine environments. As a unique habitat within marine ecosystems, cold seeps have received considerable interest in recent years. This study explores the lifestyle of a new symbiotic SOB in a cold seep sponge. The results demonstrate that both this sponge symbiont and endosymbionts in deep-sea clams employ similar strategies of genome reduction. However, this bacterium has retained unique functions for immunity and defense. Thus, the functional features are determined by both the symbiotic relationship and host type. Moreover, analyses of the genome of an AOA suggest that microbes play different roles in biochemical cycles in the sponge body. Our findings provide new insights into invertebrate-associated bacteria in cold seep environments.

10.
Environ Microbiol ; 18(8): 2481-94, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-26637128

RESUMO

Glass sponge (Hexactinellida, Porifera) is a special lineage because of its unique tissue organization and skeleton material. Structure and physiology of glass sponge have been extensively studied. However, our knowledge of the glass sponge-associated microbial community and of the interaction with the host is rather limited. Here, we performed genomic studies on the microbial community in the glass sponge Lophophysema eversa in seamount. The microbial community was dominated by an ammonia-oxidizing archaeum (AOA), a nitrite-oxidizing bacterium (NOB) and a sulfur-oxidizing bacterium (SOB), all of which were autotrophs. Genomic analysis on the AOA, NOB and SOB in the sponge revealed specific functional features of sponge-associated microorganisms in comparison with the closely related free-living relatives, including chemotaxis, phage defence, vitamin biosynthesis and nutrient uptake among others, which are related to ecological functions. The three autotrophs play essential roles in the cycles of carbon, nitrogen and sulfur in the microenvironment inside the sponge body, and they are considered to play symbiotic roles in the host as scavengers of toxic ammonia, nitrite and sulfide. Our study extends knowledge regarding the metabolism and the evolution of chemolithotrophs inside the invertebrate body.


Assuntos
Archaea/isolamento & purificação , Carbono/metabolismo , Gammaproteobacteria/isolamento & purificação , Nitrogênio/metabolismo , Poríferos/microbiologia , Enxofre/metabolismo , Amônia/metabolismo , Animais , Archaea/classificação , Archaea/genética , Processos Autotróficos/fisiologia , Gammaproteobacteria/classificação , Gammaproteobacteria/genética , Genoma Arqueal/genética , Genoma Bacteriano/genética , Genômica , Microbiota/genética , Oxirredução , Filogenia , Simbiose
11.
Genome Biol Evol ; 7(8): 2310-20, 2015 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-26220935

RESUMO

Horizontal gene transfer (HGT) of operational genes has been widely reported in prokaryotic organisms. However, informational genes such as those involved in transcription and translation processes are very difficult to be horizontally transferred, as described by Woese's complexity hypothesis. Here, we analyzed all of the completed prokaryotic genome sequences (2,143 genomes) in the NCBI (National Center for Biotechnology Information) database, scanned for genomes with high intragenomic heterogeneity of 16S rRNA gene copies, and explored potential HGT events of ribosomal RNA genes based on the phylogeny, genomic organization, and secondary structures of the ribosomal RNA genes. Our results revealed 28 genomes with relatively high intragenomic heterogeneity of multiple 16S rRNA gene copies (lowest pairwise identity <98.0%), and further analysis revealed HGT events and potential donors of the heterogeneous copies (such as HGT from Chlamydia suis to Chlamydia trachomatis) and mutation events of some heterogeneous copies (such as Streptococcus suis JS14). Interestingly, HGT of the 16S rRNA gene only occurred at intragenus or intraspecies levels, which is quite different from the HGT of operational genes. Our results improve our understanding regarding the exchange of informational genes.


Assuntos
Transferência Genética Horizontal , Genes Arqueais , Genes Bacterianos , RNA Ribossômico 16S/genética , Chlamydia/genética , Escherichia coli/genética , Dosagem de Genes , Variação Genética , Genoma Arqueal , Genoma Bacteriano , Mutação , Filogenia , Thermoanaerobacter/genética
12.
PeerJ ; 3: e890, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26082867

RESUMO

Sponge diseases have been widely reported, yet the causal factors and major pathogenic microbes remain elusive. In this study, two individuals of the sponge Crella cyathophora in total that showed similar disease-like characteristics were collected from two different locations along the Red Sea coast separated by more than 30 kilometers. The disease-like parts of the two individuals were both covered by green surfaces, and the body size was much smaller compared with adjacent healthy regions. Here, using high-throughput pyrosequencing technology, we investigated the prokaryotic communities in healthy and disease-like sponge tissues as well as adjacent seawater. Microbes in healthy tissues belonged mainly to the Proteobacteria, Cyanobacteria and Bacteroidetes, and were much more diverse at the phylum level than reported previously. Interestingly, the disease-like tissues from the two sponge individuals underwent shifts of prokaryotic communities and were both enriched with a novel clade affiliated with the phylum Verrucomicrobia, implying its intimate connection with the disease-like Red Sea sponge C. cyathophora. Enrichment of the phylum Verrucomicrobia was also considered to be correlated with the presence of algae assemblages forming the green surface of the disease-like sponge tissues. This finding represents an interesting case of sponge disease and is valuable for further study.

13.
mBio ; 5(6): e01980, 2014 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-25370493

RESUMO

UNLABELLED: Marine sponges are the most primitive metazoan and host symbiotic microorganisms. They are crucial components of the marine ecological system and play an essential role in pelagic processes. Copper pollution is currently a widespread problem and poses a threat to marine organisms. Here, we examined the effects of copper treatment on the composition of the sponge-associated bacterial community and the genetic features that facilitate the survival of enriched bacteria under copper stress. The 16S rRNA gene sequencing results showed that the sponge Haliclona cymaeformis harbored symbiotic sulfur-oxidizing Ectothiorhodospiraceae and photosynthetic Cyanobacteria as dominant species. However, these autotrophic bacteria decreased substantially after treatment with a high copper concentration, which enriched for a heterotrophic-bacterium-dominated community. Metagenomic comparison revealed a varied profile of functional genes and enriched functions, including bacterial motility and chemotaxis, extracellular polysaccharide and capsule synthesis, virulence-associated genes, and genes involved in cell signaling and regulation, suggesting short-period mechanisms of the enriched bacterial community for surviving copper stress in the microenvironment of the sponge. Microscopic observation and comparison revealed dynamic bacterial aggregation within the matrix and lysis of sponge cells. The bacteriophage community was also enriched, and the complete genome of a dominant phage was determined, implying that a lytic phage cycle was stimulated by the high copper concentration. This study demonstrated a copper-induced shift in the composition of functional genes of the sponge-associated bacterial community, revealing the selective effect of copper treatment on the functions of the bacterial community in the microenvironment of the sponge. IMPORTANCE: This study determined the bacterial community structure of the common sponge Haliclona cymaeformis and examined the effect of copper treatment on the community structure and functional gene composition, revealing that copper treatment had a selective effect on the functions of the bacterial community in the sponge. These findings suggest that copper pollution has an ecological impact on the sponge symbiont. The analysis showed that the untreated sponges hosted symbiotic autotrophic bacteria as dominant species, and the high-concentration copper treatment enriched for a heterotrophic bacterial community with enrichment for genes important for bacterial motility, supplementary cellular components, signaling and regulation, and virulence. Microscopic observation showed obvious bacterial aggregation and a reduction of sponge cell numbers in treated sponges, which suggested the formation of aggregates to reduce the copper concentration. The enrichment for functions of directional bacterial movement and supplementary cellular components and the formation of bacterial aggregates and phage enrichment are novel findings in sponge studies.


Assuntos
Bactérias/classificação , Bactérias/efeitos dos fármacos , Bacteriófagos/classificação , Biota/efeitos dos fármacos , Cobre/toxicidade , Haliclona/microbiologia , Animais , Bactérias/genética , Bacteriófagos/genética , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
14.
Sci Rep ; 4: 6647, 2014 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-25323200

RESUMO

Studies focusing on biofilm assembly in deep-sea environments are rarely conducted. To examine the effects of substrate type on microbial community assembly, biofilms were developed on different substrates for different durations at two locations in the Red Sea: in a brine pool and in nearby bottom water (NBW) adjacent to the Thuwal cold seep II. The composition of the microbial communities in 51 biofilms and water samples were revealed by classification of pyrosequenced 16S rRNA gene amplicons. Together with the microscopic characteristics of the biofilms, the results indicate a stronger selection effect by the substrates on the microbial assembly in the brine pool compared with the NBW. Moreover, the selection effect by substrate type was stronger in the early stages compared with the later stages of the biofilm development. These results are consistent with the hypotheses proposed in the framework of species sorting theory, which states that the power of species sorting during microbial community assembly is dictated by habitat conditions, duration and the structure of the source community. Therefore, the results of this study shed light on the control strategy underlying biofilm-associated marine fouling and provide supporting evidence for ecological theories important for understanding the formation of deep-sea biofilms.


Assuntos
Biofilmes , Biologia Marinha , RNA Ribossômico 16S/genética , Microbiologia da Água , Oceano Índico , Filogenia , Especificidade por Substrato
15.
Environ Microbiol ; 16(11): 3548-61, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25088944

RESUMO

Sulfur-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) play essential roles in marine sponges. However, the detailed characteristics and physiology of the bacteria are largely unknown. Here, we present and analyse the first genome of sponge-associated SOB using a recently developed metagenomic binning strategy. The loss of transposase and virulence-associated genes and the maintenance of the ancient polyphosphate glucokinase gene suggested a stabilized SOB genome that might have coevolved with the ancient host during establishment of their association. Exclusive distribution in sponge, bacterial detoxification for the host (sulfide oxidation) and the enrichment for symbiotic characteristics (genes-encoding ankyrin) in the SOB genome supported the bacterial role as an intercellular symbiont. Despite possessing complete autotrophic sulfur oxidation pathways, the bacterium developed a much more versatile capacity for carbohydrate uptake and metabolism, in comparison with its closest relatives (Thioalkalivibrio) and to other representative autotrophs from the same order (Chromatiales). The ability to perform both autotrophic and heterotrophic metabolism likely results from the unstable supply of reduced sulfur in the sponge and is considered critical for the sponge-SOB consortium. Our study provides insights into SOB of sponge-specific clade with thioautotrophic and versatile heterotrophic metabolism relevant to its roles in the micro-environment of the sponge body.


Assuntos
Bactérias/metabolismo , Genoma Bacteriano , Processos Heterotróficos/genética , Poríferos/microbiologia , Enxofre/metabolismo , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Metabolismo dos Carboidratos , Gammaproteobacteria/genética , Gammaproteobacteria/isolamento & purificação , Gammaproteobacteria/metabolismo , Genômica , Oxirredução , Filogenia , Simbiose
16.
Microb Ecol ; 68(3): 621-32, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24760170

RESUMO

Abnormality and disease in sponges have been widely reported, yet how sponge-associated microbes respond correspondingly remains inconclusive. Here, individuals of the sponge Carteriospongia foliascens under abnormal status were collected from the Rabigh Bay along the Red Sea coast. Microbial communities in both healthy and abnormal sponge tissues and adjacent seawater were compared to check the influences of these abnormalities on sponge-associated microbes. In healthy tissues, we revealed low microbial diversity with less than 100 operational taxonomic units (OTUs) per sample. Cyanobacteria, affiliated mainly with the sponge-specific species "Candidatus Synechococcus spongiarum," were the dominant bacteria, followed by Bacteroidetes and Proteobacteria. Intraspecies dynamics of microbial communities in healthy tissues were observed among sponge individuals, and potential anoxygenic phototrophic bacteria were found. In comparison with healthy tissues and the adjacent seawater, abnormal tissues showed dramatic increase in microbial diversity and decrease in the abundance of sponge-specific microbial clusters. The dominated cyanobacterial species Candidatus Synechococcus spongiarum decreased and shifted to unspecific cyanobacterial clades. OTUs that showed high similarity to sequences derived from diseased corals, such as Leptolyngbya sp., were found to be abundant in abnormal tissues. Heterotrophic Planctomycetes were also specifically enriched in abnormal tissues. Overall, we revealed the microbial communities of the cyanobacteria-rich sponge, C. foliascens, and their impressive shifts under abnormality.


Assuntos
Bactérias/classificação , Filogenia , Poríferos/microbiologia , Animais , Bactérias/genética , DNA Bacteriano/genética , Oceano Índico , RNA Ribossômico 16S/genética , Água do Mar/microbiologia , Análise de Sequência de DNA
17.
mBio ; 5(2): e00079-14, 2014 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-24692632

RESUMO

"Candidatus Synechococcus spongiarum" is a cyanobacterial symbiont widely distributed in sponges, but its functions at the genome level remain unknown. Here, we obtained the draft genome (1.66 Mbp, 90% estimated genome recovery) of "Ca. Synechococcus spongiarum" strain SH4 inhabiting the Red Sea sponge Carteriospongia foliascens. Phylogenomic analysis revealed a high dissimilarity between SH4 and free-living cyanobacterial strains. Essential functions, such as photosynthesis, the citric acid cycle, and DNA replication, were detected in SH4. Eukaryoticlike domains that play important roles in sponge-symbiont interactions were identified exclusively in the symbiont. However, SH4 could not biosynthesize methionine and polyamines and had lost partial genes encoding low-molecular-weight peptides of the photosynthesis complex, antioxidant enzymes, DNA repair enzymes, and proteins involved in resistance to environmental toxins and in biosynthesis of capsular and extracellular polysaccharides. These genetic modifications imply that "Ca. Synechococcus spongiarum" SH4 represents a low-light-adapted cyanobacterial symbiont and has undergone genome streamlining to adapt to the sponge's mild intercellular environment. IMPORTANCE Although the diversity of sponge-associated microbes has been widely studied, genome-level research on sponge symbionts and their symbiotic mechanisms is rare because they are unculturable. "Candidatus Synechococcus spongiarum" is a widely distributed uncultivated cyanobacterial sponge symbiont. The genome of this symbiont will help to characterize its evolutionary relationship and functional dissimilarity to closely related free-living cyanobacterial strains. Knowledge of its adaptive mechanism to the sponge host also depends on the genome-level research. The data presented here provided an alternative strategy to obtain the draft genome of "Ca. Synechococcus spongiarum" strain SH4 and provide insight into its evolutionary and functional features.


Assuntos
Genoma Bacteriano , Poríferos/microbiologia , Poríferos/fisiologia , Simbiose , Synechococcus/genética , Synechococcus/fisiologia , Adaptação Biológica , Animais , Evolução Molecular , Redes e Vias Metabólicas/genética , Dados de Sequência Molecular , Análise de Sequência de DNA
18.
PLoS One ; 9(3): e90053, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24594623

RESUMO

Eukaryotic 18S ribosomal RNA (rRNA) gene primers that feature a wide coverage are critical in detecting the composition of eukaryotic microscopic organisms in ecosystems. Here, we predicted 18S rRNA primers based on consecutive conserved sites and evaluated their coverage efficiency and scope of application to different eukaryotic groups. After evaluation, eight of them were considered as qualified 18S primers based on coverage rate. Next, we examined common conserved regions in prokaryotic 16S and eukaryotic 18S rRNA sequences to design 16S/18S universal primers. Three 16S/18S candidate primers, U515, U1390 and U1492, were then considered to be suitable for simultaneous amplification of the rRNA sequences in three domains. Eukaryotic 18S and prokaryotic 16S rRNA genes in a sponge were amplified simultaneously using universal primers U515 and U1390, and the subsequent sorting of pyrosequenced reads revealed some distinctive communities in different parts of the sample. The real difference in biodiversity between prokaryotic and eukaryotic symbionts could be discerned as the dissimilarity between OTUs was increased from 0.005 to 0.1. A network of the communities in external and internal parts of the sponge illustrated the co-variation of some unique microbes in certain parts of the sponge, suggesting that the universal primers are useful in simultaneous detection of prokaryotic and eukaryotic microbial communities.


Assuntos
RNA Ribossômico 16S/genética , RNA Ribossômico 18S/genética , Simbiose , Sequência de Bases , Sequência Conservada , Primers do DNA , Homologia de Sequência do Ácido Nucleico
19.
Front Microbiol ; 5: 37, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24575081

RESUMO

A hypoxic/suboxic brine pool at a depth of about 850 m was discovered near the Thuwal cold seeps in the Red Sea. Filled with high concentrations of hydrogen sulfide and ammonia, such a brine pool might limit the spread of eukaryotic organisms. Here, we compared the communities of the eukaryotic microbes in a microbial mat, sediments and water samples distributed in 7 sites within and adjacent to the brine pool. Taxonomic classification of the pyrosequenced 18S rRNA amplicon reads showed that fungi highly similar to the species identified along the Arabic coast were almost ubiquitous in the water and sediment samples, supporting their wide distribution in various environments. The microbial mat displayed the highest species diversity and contained grazers and a considerable percentage of unclassified species. Phylogeny-based methods revealed novel lineages representing a majority of the reads from the interface between the sea water and brine pool. Phylogenetic relationships with more reference sequences suggest that the lineages were affiliated with novel Alveolata and Euglenozoa inhabiting the interface where chemosynthetic prokaryotes are highly proliferative due to the strong chemocline and halocline. The brine sediments harbored abundant species highly similar to invertebrate gregarine parasites identified in different oxygen-depleted sediments. Therefore, the present findings support the uniqueness of some microbial eukaryotic groups in this cold seep brine system.

20.
Front Microbiol ; 5: 799, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25642227

RESUMO

Marine sponges play important roles in benthic environments and are sensitive to environmental stresses. Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants since the 1970s and are cytotoxic and genotoxic to organisms. In the present study, we studied the short-period effect of PBDE-47 (2,2',4,4'-tetrabromodiphenyl ether) treatment on the community structure and functional gene composition of the bacterial community inhabiting the marine sponge Haliclona cymaeformis. Our results showed that the bacterial community shifted from an autotrophic bacteria-dominated community to a heterotrophic bacteria-dominated community in response to PBDE-47 in a time- and concentration-dependent manner. A potentially symbiotic sulfur-oxidizing bacterium (SOB) was dominant (>80% in abundance) in the untreated sponge. However, exposure to a high concentration (1 µg/L) of PBDE-47 caused a substantial decrease in the potential symbiont and an enrichment of heterotrophic bacteria like Clostridium. A metagenomic analysis showed a selective effect of the high concentration treatment on the functional gene composition of the enriched heterotrophic bacteria, revealing an enrichment for the functions responsible for DNA repair, multidrug efflux pumping, and bacterial chemotaxis and motility. This study demonstrated that PBDE-47 induced a shift in the composition of the community and functional genes in the sponge-associated bacterial community, revealing the selective effect of PBDE-47 treatment on the functions of the bacterial community in the microenvironment of the sponge.

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