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1.
Int J Syst Evol Microbiol ; 71(10)2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34705626

RESUMO

Parvularcula flava was proposed as a novel member of genus Parvularcula in 2016. Some time earlier, Aquisalinus flavus has been proposed as a novel species of a novel genus named Aquisalinus. When comparing the 16S rRNA gene sequences of type strains P. flava NH6-79T and A. flavus D11M-2T, they showed 97.9 % sequence identity, much higher than the sequence identities 92.7-94.3 % between P. flava NH6-79T and type strains in the genus Parvularcula, indicating that the later proposed novel taxon Parvularcula flava need reclassification. The phylogenetic trees based on 16S rRNA gene sequences and genome sequences both showed that P. flava NH6-79T and A. flavus D11M-2T formed a separated branch away from strains in the genera Parvularcula, Marinicaulis and Amphiplicatus. The average amino acid identity and average nucleotide identity values of P. flava NH6-79T and A. flavus D11M-2T were 87.9 and 85.0 %, respectively, much higher than the values between P. flava NH6-79T and other closely related type strains (54.3 %-58.1 % and 68.6-70.4 %, respectively). P. flava NH6-79T and A. flavus D11M-2T also contained summed feature 8 (C18 : 1 ω6c and/or C18 : 1 ω7c) and C16 : 0 as major fatty acids, distinguishing them from other closely related taxa. Based on the results of the phylogenetic, comparative genomic and phenotypic analyses, Parvularcula flava should be reclassified as Aquisalinus luteolus nom. nov. and the description of genus Aquisalinus is emended.


Assuntos
Ácidos Graxos , Fosfolipídeos , Alphaproteobacteria , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
2.
Nat Commun ; 12(1): 5949, 2021 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-34642318

RESUMO

Directed motility enables swimming microbes to navigate their environment for resources via chemo-, photo-, and magneto-taxis. However, directed motility competes with fluid flow in porous microbial habitats, affecting biofilm formation and disease transmission. Despite this broad importance, a microscopic understanding of how directed motility impacts the transport of microswimmers in flows through constricted pores remains unknown. Through microfluidic experiments, we show that individual magnetotactic bacteria directed upstream through pores display three distinct regimes, whereby cells swim upstream, become trapped within a pore, or are advected downstream. These transport regimes are reminiscent of the electrical conductivity of a diode and are accurately predicted by a comprehensive Langevin model. The diode-like behavior persists at the pore scale in geometries of higher dimension, where disorder impacts conductivity at the sample scale by extending the trapping regime over a broader range of flow speeds. This work has implications for our understanding of the survival strategies of magnetotactic bacteria in sediments and for developing their use in drug delivery applications in vascular networks.


Assuntos
Alphaproteobacteria/fisiologia , Campos Magnéticos , Movimento/fisiologia , Resposta Táctica/fisiologia , Biofilmes/crescimento & desenvolvimento , Condutividade Elétrica , Técnicas Analíticas Microfluídicas , Porosidade , Reologia
3.
G3 (Bethesda) ; 11(9)2021 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-34544124

RESUMO

Oceanicaulis alexandrii strain NP7 is a marine bacterium which belongs to the Hyphomonadaceae family and was isolated from sediments highly contaminated with metals and polycyclic aromatic hydrocarbons released for decades by industrial activities in the Gulf of Naples (Mediterranean Sea). Here, we report the partial genome sequence and annotation of O. alexandrii strain NP7 that contains a chromosome of 2,954,327 bp and encodes for 2914 predicted coding sequences (CDSs) and 44 RNA-encoding genes. Although the presence of some CDSs for genes involved in hydrocarbon degradation processes (e.g., alkB) have already been described in the literature associated with the Oceanicaulis, this is the first time that more than 100 genes involved in metal detoxification processes and hydrocarbon degradation are reported belonging to this genus. The presence of a heterogeneous set of genes involved in stress response, hydrocarbon degradation, heavy metal resistance, and detoxification suggests a possible role for O. alexandrii NP7 in the bioremediation of these highly contaminated marine sediments.


Assuntos
Sedimentos Geológicos , Metagenoma , Alphaproteobacteria , Biodegradação Ambiental , Mar Mediterrâneo
4.
Artigo em Inglês | MEDLINE | ID: mdl-34388084

RESUMO

A novel bacterial strain, designated SW136T, was isolated from a deep-sea sediment sample collected from the South China Sea. Cells were Gram-stain-negative, aerobic, catalase-positive and oxidase-positive. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SW136T represented a novel member of the genus Aurantimonas, forming a distinct cluster with 'Aurantimonas litoralis', Aurantimonas coralicida and Aurantimonas manganoxydans (98.2, 98.1 and 97.9% sequence similarity, respectively). The predominant cellular fatty acid of strain SW136T was C18 : 1 ω7c. Strain SW136T contained ubiquinone-10 as the dominant respiratory quinone, and diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and phosphatidylglycerol as the major polar lipids. The genomic DNA G+C content was 64.3 mol%. The average nucleotide identity and digital DNA-DNA hybridization values of strain SW136T with A. coralicida CGMCC 1.12222T and A. manganoxydans CGMCC 1.12225T were 78.8 and 78.6 % and 21.5 and 25.5 %, respectively. On the basis of phylogenetic inference and phenotypic characteristics, we propose that strain SW136T represents a novel species of the genus Aurantimonas, with the name Aurantimonas marina sp. nov. The type strain is SW136T (=CGMCC 1.17725T=KCTC 82366T).


Assuntos
Alphaproteobacteria/classificação , Sedimentos Geológicos , Filogenia , Água do Mar/microbiologia , Alphaproteobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Sedimentos Geológicos/microbiologia , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/análogos & derivados , Ubiquinona/química
5.
Antonie Van Leeuwenhoek ; 114(10): 1633-1645, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34333698

RESUMO

A Gram-stain negative, non-motile, brilliant yellow and non-spore forming, coccoid- or short rod-shaped bacterium, designated strain KSK16Y-1T, was isolated from surface-sterilised leaf of Rhizophora stylosa collected from Shankou Mangrove Nature Reserve, Guangxi Zhuang Autonomous Region, China. Genome of strain KSK16Y-1T is 4.93 Mb with 68.1% DNA G + C content and encoded 4359 predicted proteins, 4 rRNAs, 45 tRNAs and 4 ncRNA. Comparative 16S rRNA gene sequence analysis showed that the strain KSK16Y-1T has 98.1%, 97.9% and 96.9% 16S rRNA gene similarities with Jiella aquimaris JCM 30119T, J. endophytica CBS5Q-3T and J. pacifica 40Bstr34T, respectively. Whole-genome comparisons between strain KSK16Y-1T and J. aquimaris 22II-16-19i, J. endophytica CBS5Q-3T, J. pacifica 40Bstr34T, using average nucleotide identity (ANI) values (< 82.0%) and digital DNA-DNA hybridization (dDDH) values (< 25.1%), confirmed low genome relatedness. Strain KSK16Y-1T grew at 20-30 °C (optimum, 30 °C), pH 6.0-11.0 (optimum, pH 6.0-7.0) and with 0-10% (w/v) NaCl (optimum, 0-2%). Cell wall contained meso-diaminopimelic acid and the major fatty acid was C18:1ω7c. The polar lipid profile consists of phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, one unknown phospholipid, one unknown aminolipid, one unknown aminophospholipid and four unidentified lipids. The predominant respiratory quinone is ubiquinone-10 (Q-10). The polyphasic characterization indicated that strain KSK16Y-1T represents a novel Jiella species. The name Jiella mangrovi sp. nov., type strain KSK16Y-1T (= CGMCC 1.18745T = JCM 34332T) is proposed.


Assuntos
Rhizophoraceae , Alphaproteobacteria , Técnicas de Tipagem Bacteriana , China , DNA Bacteriano/genética , Ácidos Graxos/análise , Fosfolipídeos/análise , Filogenia , Folhas de Planta , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
6.
Artigo em Inglês | MEDLINE | ID: mdl-34264808

RESUMO

A novel Gram-stain-negative, rod-shaped, yellow bacterium, designated as LB1R16T, was isolated from the Laigu glacier on the Tibetan Plateau, PR China. Strain LB1R16T was catalase-positive, oxidase-negative and grew at 0-28 °C, pH 6.0-8.0 and in the absence of NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain LB1R16T belongs to the family Sphingosinicellaceae but formed an independent lineage. The highest level of 16S rRNA gene sequence similarities were found to Polymorphobacter arshaanensis DJ1R-1T (95.24 %), Sphingoaurantiacus capsulatus YLT33T (94.78 %) and Sandarakinorhabdus limnophila DSM 17366T (94.67 %). The genomic DNA G+C content was 68.8 mol%. The main cellular fatty acids were summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c), summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c), C16 : 0 and C12 : 0-OH. The respiratory quinone was ubiquinone-10. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, one sphingoglycolipid, one unidentified aminolipid, one unidentified phospholipid and two unidentified polar lipids, which were different from the type strains of Polymorphobacter arshaanensis, Sphingoaurantiacus capsulatus and Sandarakinorhabdus limnophila. Based on a polyphasic approach, a novel species of a new genus, Glacieibacterium frigidum gen. nov., sp. nov., within the family Sphingosinicellaceae is proposed. The type strain is LB1R16T (=CGMCC 1.11941T=NBRC 113873T).


Assuntos
Alphaproteobacteria/classificação , Camada de Gelo/microbiologia , Filogenia , Alphaproteobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/análogos & derivados , Ubiquinona/química
7.
Artigo em Inglês | MEDLINE | ID: mdl-34270400

RESUMO

A novel Gram-stain-negative, aerobic and rod-shaped bacterial strain designated as 6D45AT was isolated from mangrove soil and characterized using a polyphasic taxonomic approach. Strain 6D45AT was found to grow at 10-37 °C (optimum, 28 °C), at pH 6.0-9.0 (optimum, 7.0) and in 0-5 % (w/v) NaCl (optimum, 2%). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 6D45AT fell into the genus Salipiger and shared 99.1 % identity with the closest type strain Salipiger pacificus CGMCC 1.3455T and less than 97.2 % identity with other type strains of this genus. The 34.8 % digital DNA-DNA hybridization (dDDH) and 88.3 % average nucleotide identity (ANI) values between strain 6D45AT and the closest relative above were well below recognized thresholds of 70 % DDH and 95-96 % ANI for species definition, implying that strain 6D45AT should represent a novel genospecies. The phylogenomic analysis indicated that strain 6D45AT formed an independent branch distinct from reference strains. The predominant cellular fatty acid of strain 6D45AT was summed feature 8 (C18 : 1 ω6c and/or C18 : 1 ω7c, 66.9 %); the polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, two unidentified aminolipids, two unidentified glycolipids and an unknown lipid; the respiratory quinone was Q-10. The genomic DNA G+C content was 66.5 mol %. Based on the phenotypic and genotypic characteristics, strain 6D45AT is concluded to represent a novel species of the genus Salipiger, for which the name Salipiger mangrovisoli sp. nov., is proposed. The type strain of the species is 6D45AT (=GDMCC 1.1960T=KCTC 82334T). We also propose the reclassification of Paraphaeobacter pallidus as Salipiger pallidus comb. nov. and 'Pelagibaca abyssi' as a species of the genus Salipiger.


Assuntos
Alphaproteobacteria/classificação , Filogenia , Microbiologia do Solo , Alphaproteobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Glicolipídeos/química , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Rhodobacteraceae/classificação , Análise de Sequência de DNA , Ubiquinona/análogos & derivados , Ubiquinona/química , Áreas Alagadas
8.
Artigo em Inglês | MEDLINE | ID: mdl-34224346

RESUMO

Two bacterial strains, designated as 1-4-3T and 1-4-4, were isolated from a mangrove sediment cultured with coastal seawater. The cells were Gram-stain-negative, motile, short, rod-shaped bacteria with flagella. Growth occurred at 4-37 °C, pH 7.0-9.0, and 0-7% NaCl. The predominant fatty acids of the novel strains were C18 : 1 ω7c, C19 : 0 cyclo ω8c, C18 : 0, and C16 : 0. A phylogenetic analysis based on 16S rRNA gene sequences and whole genome phylogeny analysis based on distance matrix revealed an affiliation between the two strains and the genus Aureimonas, with closest sequence similarity to A. populi 4M3-2T (96.41 and 96.64% similarity, respectively) and A. glaciistagni (96.01 and 96.23% similarity, respectively). The DNA G+C content of strain 1-4-3T was 66.80 mol%. Strain 1-4-3T displayed low DNA-DNA relatedness to A. populi 4M3-2T, with an average nucleotide identity value of 77.47 % and digital DNA-DNA hybridization value of 22.83 %. Genotypic, chemotaxonomic, and phenotypic data indicate that strains 1-4-3T and 1-4-4 represent a novel species of the genus Aureimonas, for which we propose the name Aureimonas mangrovi sp. nov. The type strain is 1-4-3T (=LMG 31693T=CGMCC 1.18507T).


Assuntos
Alphaproteobacteria/classificação , Sedimentos Geológicos/microbiologia , Filogenia , Água do Mar/microbiologia , Alphaproteobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Tailândia , Áreas Alagadas
9.
Artigo em Inglês | MEDLINE | ID: mdl-34228608

RESUMO

A Gram-stain-negative, strictly aerobic, motile bacterium, designated strain RKSG073T, was isolated from the sea sponge Aplysina fistularis, collected off the west coast of San Salvador, The Bahamas. Cells were curved-to-spiral rods with single, bipolar (amphitrichous) flagella, oxidase- and catalase-positive, non-nitrate-reducing and required salt for growth. RKSG073T grew optimally at 30-37 °C, pH 6-7, and with 2-3 % (w/v) NaCl. The predominant fatty acids of RKSG073T were summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c) and C16 : 0. Major isoprenoid quinones were identified as Q-10 and Q-9. Phylogenetic analyses of nearly complete 16S rRNA genes and genome sequences positioned strain RKSG073T in a clade with its closest relative Aestuariispira insulae AH-MY2T (92.1 % 16S rRNA gene sequence similarity), which subsequently clustered with Hwanghaeella grinnelliae Gri0909T, Marivibrio halodurans ZC80T and type species of the genera Kiloniella, Thalassospira and Terasakiella. The DNA G+C content calculated from the genome of RKSG073T was 42.2 mol%. On the basis of phylogenetic distinctiveness and polyphasic analysis, here we propose that RKSG073T (culture deposit numbers: ATCC collection = TSD-74T, BCCM collection = LMG 29869T) represents the type strain of a novel genus and species within the family Kiloniellaceae, order Rhodospirillales and class Alphaproteobacteria, for which the name Curvivirga aplysinae gen. nov., sp. nov. is proposed.


Assuntos
Alphaproteobacteria/classificação , Filogenia , Poríferos/microbiologia , Alphaproteobacteria/isolamento & purificação , Animais , Técnicas de Tipagem Bacteriana , Bahamas , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/química
10.
Artigo em Inglês | MEDLINE | ID: mdl-34296989

RESUMO

Strains M65T, M69 and JN25 were isolated from seawater of the West Pacific Ocean. Cells of the three strains were Gram-stain-negative, aerobic and rod-shaped. Cells were motile by means of flagella. On the basis of the results of 16S rRNA gene sequence analysis, strains M65T, M69 and JN25 showed the highest 16S rRNA gene sequence similarity to Henriciella algicola MCS27T (98.8 %), followed by Henriciella marina DSM 19595T (98.4 %), Henriciella barbarensis MCS23T (98.4 %), Henriciella pelagia LA220T (98.3 %), Henriciella aquimarina P38T (98.1 %) and Henriciella litoralis SD10T (97.8 %). The 16S rRNA gene sequence similarities among the isolates were 100 %. Phylogenetic analyses revealed that the isolates fell within a cluster comprising the Henriciella species and represented an independent lineage. The average nucleotide identity and in silico DNA-DNA hybridization values between strain M65T and the type strains of Henriciella species were 73.9-85.8 % and 19.9-22.4 %, respectively. The sole respiratory quinone detected in the three isolates was ubiquinone 10. The principal fatty acids were summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) and C16 : 0. The major polar lipids were glucuronopyranosyldiglyceride, monoglycosyldiglyceride and one unidentified glycolipid. The DNA G+C content was 61.3-61.4 mol%. Phylogenetic distinctiveness, chemotaxonomic differences, together with phenotypic properties, revealed that the isolates could be differentiated from the Henriciella species with validly published names. Therefore, it is proposed that strains M65T, M69 and JN25 represent a novel species of the genus Henriciella, for which the name Henriciella mobilis sp. nov. (type strain, M65T=CGMCC 1.15927T=KCTC 52576T) is proposed.


Assuntos
Alphaproteobacteria/classificação , Filogenia , Água do Mar/microbiologia , Alphaproteobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Oceano Pacífico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/análogos & derivados , Ubiquinona/química
11.
Water Res ; 202: 117454, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34332189

RESUMO

The artificial sweetener Acesulfame (ACE) has been frequently detected in wastewater treatment plants (WWTPs) and is regarded as an emerging pollutant due to its low biodegradability. However, recent observations of ACE biodegradation in WWTPs have stimulated interest in the ACE-degrading bacteria and mineralization pathways. In this study, next-generation sequencing methods, Illumina and Nanopore sequencing, were combined to explore the ACE-degrading communities enriched from the activated sludge of six municipal wastewater treatment plants. Metagenomic investigations indicated that all enrichments were similarly dominated by the phyla Proteobacteria and Planctomycetes. Notably, at the species level, four metagenome-assembled genomes (MAGs) were shared by six enriched communities with considerable abundances, indicating that they may be responsible for ACE biodegradation in the enrichments. Besides, two ACE-degrading pure strains, affiliated to the genus Chelatococcus, were isolated from the enrichment. The genomic analysis showed that these two isolates were the new species that were genetically distinct from their relatives. Two type strains, Chelatococcus asaccharovorans DSM 6462 and Chelatococcus composti DSM 101465, could not degrade ACE, implying that the ACE-degrading capability was not shared among the different species in the genus Chelatococcus. The results of the degradation experiment showed that the two isolates could use ACE as the sole carbon source and mineralize ~90% of the total organic carbon. Three biotransformation products (TP96, TP180B, and TP182B) were demonstrated by UPLC-QTOF-MS. The results of this study provide valuable insights into ACE biodegradation and its biotransformation products.


Assuntos
Genômica , Edulcorantes , Alphaproteobacteria , Biodegradação Ambiental , Cinética , Tiazinas
12.
Int J Mol Sci ; 22(11)2021 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-34073951

RESUMO

Cytochrome P450 monooxygenases (CYPs/P450s), heme-thiolate proteins, are well-known players in the generation of chemicals valuable to humans and as a drug target against pathogens. Understanding the evolution of P450s in a bacterial population is gaining momentum. In this study, we report comprehensive analysis of P450s in the ancient group of the bacterial class Alphaproteobacteria. Genome data mining and annotation of P450s in 599 alphaproteobacterial species belonging to 164 genera revealed the presence of P450s in only 241 species belonging to 82 genera that are grouped into 143 P450 families and 214 P450 subfamilies, including 77 new P450 families. Alphaproteobacterial species have the highest average number of P450s compared to Firmicutes species and cyanobacterial species. The lowest percentage of alphaproteobacterial species P450s (2.4%) was found to be part of secondary metabolite biosynthetic gene clusters (BGCs), compared other bacterial species, indicating that during evolution large numbers of P450s became part of BGCs in other bacterial species. Our study identified that some of the P450 families found in alphaproteobacterial species were passed to other bacterial species. This is the first study to report on the identification of CYP125 P450, cholesterol and cholest-4-en-3-one hydroxylase in alphaproteobacterial species (Phenylobacterium zucineum) and to predict cholesterol side-chain oxidation capability (based on homolog proteins) by P. zucineum.


Assuntos
Alphaproteobacteria/genética , Vias Biossintéticas/genética , Sistema Enzimático do Citocromo P-450/genética , Família Multigênica , Metabolismo Secundário/genética , Colesterol/metabolismo , Cianobactérias/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Mineração de Dados , Evolução Molecular , Firmicutes/genética , Genoma Bacteriano , Mycobacterium tuberculosis/genética , Filogenia , Streptomyces/genética
13.
Nat Commun ; 12(1): 3324, 2021 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-34083540

RESUMO

Elucidating the timescale of the evolution of Alphaproteobacteria, one of the most prevalent microbial lineages in marine and terrestrial ecosystems, is key to testing hypotheses on their co-evolution with eukaryotic hosts and Earth's systems, which, however, is largely limited by the scarcity of bacterial fossils. Here, we incorporate eukaryotic fossils to date the divergence times of Alphaproteobacteria, based on the mitochondrial endosymbiosis that mitochondria evolved from an alphaproteobacterial lineage. We estimate that Alphaproteobacteria arose ~1900 million years (Ma) ago, followed by rapid divergence of their major clades. We show that the origin of Rickettsiales, an order of obligate intracellular bacteria whose hosts are mostly animals, predates the emergence of animals for ~700 Ma but coincides with that of eukaryotes. This, together with reconstruction of ancestral hosts, strongly suggests that early Rickettsiales lineages had established previously underappreciated interactions with unicellular eukaryotes. Moreover, the mitochondria-based approach displays higher robustness to uncertainties in calibrations compared with the traditional strategy using cyanobacterial fossils. Further, our analyses imply the potential of dating the (bacterial) tree of life based on endosymbiosis events, and suggest that previous applications using divergence times of the modern hosts of symbiotic bacteria to date bacterial evolution might need to be revisited.


Assuntos
Alphaproteobacteria/classificação , Alphaproteobacteria/genética , Eucariotos/classificação , Eucariotos/genética , Evolução Molecular , Fósseis , Animais , Cianobactérias/classificação , Cianobactérias/genética , Fósseis/história , Fósseis/microbiologia , Genoma Bacteriano , Genoma Mitocondrial , História Antiga , Mitocôndrias/genética , Mitocôndrias/microbiologia , Modelos Biológicos , Modelos Genéticos , Filogenia , Rickettsiales/classificação , Rickettsiales/genética , Simbiose/genética , Fatores de Tempo
14.
Arch Microbiol ; 203(7): 4549-4556, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34152426

RESUMO

An aerobic, Gram-stain-negative, rod-shaped bacterium with flagellum, designated L22T, was isolated from sediment of Hulun Lake, Inner Mongolia, China. The organism was found to grow optimally at 30° C in a medium containing 0-0.75% (w/v) NaCl at pH 7.5. The major fatty acid identified was summed feature 8 (C18:1ω7c). The dominant polar lipids were phosphomonoester, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylcholine. The main respiratory quinone was Q-10. The draft genome sequence of strain L22T consisted of 4354,788 bp. The G + C content of genomic DNA was 69.8 mol %. The 16S rRNA gene sequences indicated that strain L22T was affiliated with the genus Methylobrevis within the family Pleomorphomonadaceae, being most closely related to Methylobrevis pamukkalensis JCM 30229T with 95.9% 16S rRNA gene sequences similarity. The AAI, ANI and dDDH values between strain L22T and M. pamukkalensis JCM 30229T were 72.5%, 80.7% and 22.7%. Based on taxonomic results in this study, we proposed that strain L22T a novel species in the genus Methylobrevis of the family Pleomorphomonadaceae, for which the name Methylobrevis albus sp. nov. is proposed. The type strain is L22T (=KCTC 72858T=MCCC 1H00432T).


Assuntos
Alphaproteobacteria , Sedimentos Geológicos , Lagos , Alphaproteobacteria/classificação , Alphaproteobacteria/genética , China , Ácidos Graxos/análise , Sedimentos Geológicos/microbiologia , Fosfolipídeos/análise , Filogenia , RNA Ribossômico 16S/genética , Especificidade da Espécie
15.
mBio ; 12(3): e0057421, 2021 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-34154402

RESUMO

"Candidatus Midichloria mitochondrii" is a Gram-negative bacterium that lives in strict intracellular symbiosis with the hard tick Ixodes ricinus, forming one of the most intriguing endosymbiosis described to date. The bacterium is capable of durably colonizing the host mitochondria, a peculiar tropism that makes "Ca. Midichloria mitochondrii" a very interesting tool to study the physiology of these cellular organelles. The interaction between the symbiont and the organelle has, however, been difficult to characterize. A parallelism with the predatory bacterium Bdellovibrio bacteriovorus has been drawn, suggesting the hypothesis that "Ca. Midichloria mitochondrii" could prey on mitochondria and consume them to multiply. We studied the life cycle of the bacterium within the host oocytes using a multidisciplinary approach, including electron microscopy, molecular biology, statistics, and systems biology. Our results were not coherent with a predatory-like behavior by "Ca. Midichloria mitochondrii" leading us to propose a novel hypothesis for its life cycle. Based on our results, we here present a novel model called the "mitochondrion-to-mitochondrion hypothesis." Under this model, the bacterium would be able to move from mitochondrion to mitochondrion, possibly within a mitochondrial network. We show that this model presents a good fit with quantitative electron microscopy data. IMPORTANCE Our results suggest that "Candidatus Midichloria mitochondrii," the intramitochondrial bacterium, does not invade mitochondria like predatory bacteria do but instead moves from mitochondrion to mitochondrion within the oocytes of Ixodes ricinus. A better understanding of the lifestyle of "Ca. Midichloria mitochondrii" will allow us to better define the role of this bacterial symbiont in the host physiology.


Assuntos
Alphaproteobacteria/crescimento & desenvolvimento , Alphaproteobacteria/ultraestrutura , Ixodes/microbiologia , Estágios do Ciclo de Vida , Microscopia Eletrônica/métodos , Animais , DNA Bacteriano , Mitocôndrias/microbiologia , Filogenia , Simbiose
16.
Mar Pollut Bull ; 169: 112523, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34049068

RESUMO

Despite that the ballast water management (BWM) convention has come into force to prevent the spread of harmful aquatic organisms, to date, very few bacteria can be identified through microbial culture method. In this study, we explored a reduced-representation sequencing of 2b-RAD approach to investigate the bacterial diversity in ballast water and sediments (BWS). Our results indicated a large amount of bacteria species (1496) detected in BWS up to now, including 13 pathogens that are seriously concerning in marine environment and aquaculture like the most harmful Vibrio harveyi and Aurantimonas coralicida. We showed that the ballast water had relative lower species, which was dominated by Proteobacteria. In contrast, the sediments had richer species, which was dominated by Bacteroidetes. Although BWS differed significantly in species composition, sediments shared most of the concerned pathogens with ballast water, highlighting the importance of sediment management. In conclusion, 2b-RAD sequencing shows promise in future BWM.


Assuntos
Vibrio , Água , Alphaproteobacteria , Navios
17.
Curr Microbiol ; 78(7): 2623-2630, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33990868

RESUMO

The tree bark environment is an important microbial habitat distributed worldwide on thrillions of trees. However, the microbial communities of tree bark are largely unknown, with most studies on plant aerial surfaces focused on the leaves. Recently, we presented a metagenomic study of bark microbial communities from avocado. In these communities, oxygenic and anoxygenic photosynthesis genes were very abundant, especially when compared to rhizospheric soil from the same trees. In this work, Evolutionary Placement Algorithm analysis was performed on metagenomic reads orthologous to the PufLM gene cluster, encoding for the bacterial type II photosynthetic reaction center. These photosynthetic genes were found affiliated to different groups of bacteria, mostly aerobic anoxygenic photosynthetic Alphaproteobacteria, including Sphingomonas, Methylobacterium and several Rhodospirillales. These results suggest that anoxygenic photosynthesis in avocado bark microbial communities functions primarily as additional energy source for heterotrophic growth. Together with our previous results, showing a large abundance of cyanobacteria in these communities, a picture emerges of the tree holobiont, where light penetrating the tree canopies and reaching the inner stems, including the trunk, is probably utilized by cyanobacteria for oxygenic photosynthesis, and the far-red light aids the growth of aerobic anoxygenic photosynthetic bacteria.


Assuntos
Alphaproteobacteria , Microbiota , Persea , Complexo de Proteínas do Centro de Reação Fotossintética , Fotossíntese , Casca de Planta
18.
Appl Environ Microbiol ; 87(14): e0032621, 2021 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-33931419

RESUMO

In the marine environment, phosphorus availability significantly affects the lipid composition in many cosmopolitan marine heterotrophic bacteria, including members of the SAR11 clade and the Roseobacter clade. Under phosphorus stress conditions, nonphosphorus sugar-containing glycoglycerolipids are substitutes for phospholipids in these bacteria. Although these glycoglycerolipids play an important role as surrogates for phospholipids under phosphate deprivation, glycoglycerolipid synthases in marine microbes are poorly studied. In the present study, we biochemically characterized a glycolipid glycosyltransferase (GTcp) from the marine bacterium "Candidatus Pelagibacter sp." strain HTCC7211, a member of the SAR11 clade. Our results showed that GTcp is able to act as a multifunctional enzyme by synthesizing different glycoglycerolipids with UDP-glucose, UDP-galactose, or UDP-glucuronic acid as sugar donors and diacylglycerol (DAG) as the acceptor. Analyses of enzyme kinetic parameters demonstrated that Mg2+ notably changes the enzyme's affinity for UDP-glucose, which improves its catalytic efficiency. Homology modeling and mutational analyses revealed binding sites for the sugar donor and the diacylglycerol lipid acceptor, which provided insights into the retaining mechanism of GTcp with its GT-B fold. A phylogenetic analysis showed that GTcp and its homologs form a group in the GT4 glycosyltransferase family. These results not only provide new insights into the glycoglycerolipid synthesis mechanism in lipid remodeling but also describe an efficient enzymatic tool for the future synthesis of bioactive molecules. IMPORTANCE The bilayer formed by membrane lipids serves as the containment unit for living microbial cells. In the marine environment, it has been firmly established that phytoplankton and heterotrophic bacteria can replace phospholipids with nonphosphorus sugar-containing glycoglycerolipids in response to phosphorus limitation. However, little is known about how these glycoglycerolipids are synthesized. Here, we determined the biochemical characteristics of a glycolipid glycosyltransferase (GTcp) from the marine bacterium "Candidatus Pelagibacter sp." strain HTCC7211. GTcp and its homologs form a group in the GT4 glycosyltransferase family and can synthesize neutral glycolipids (monoglucosyl-1,2-diacyl-sn-glycerol [MGlc-DAG] and monogalactosyl [MGal]-DAG) and monoglucuronic acid diacylglycerol (MGlcA-DAG). We also uncovered the key residues for DAG binding through molecular docking, site-direct mutagenesis, and subsequent enzyme activity assays. Our data provide new insights into the glycoglycerolipid synthesis mechanism in lipid remodeling.


Assuntos
Alphaproteobacteria/enzimologia , Glicolipídeos/química , Glicosiltransferases/química , Alphaproteobacteria/genética , Glicosilação , Glicosiltransferases/genética , Glicosiltransferases/metabolismo , Metais Pesados/química , Especificidade por Substrato
19.
Artigo em Inglês | MEDLINE | ID: mdl-33999795

RESUMO

We isolated a novel strain, R1DC25T, described as Kaustia mangrovi gen. nov. sp. nov. from the sediments of a mangrove forest on the coast of the Red Sea in Saudi Arabia. This isolate is a moderately halophilic, aerobic/facultatively anaerobic Gram-stain-negative bacterium showing optimum growth at between 30 and 40 °C, at a pH of 8.5 and with 3-5 % NaCl. The genome of R1DC25T comprises a circular chromosome that is 4 630 536 bp in length, with a DNA G+C content of 67.3 mol%. Phylogenetic analyses based on the 16S rRNA gene sequence and whole-genome multilocus sequence analysis of 120 concatenated single-copy genes revealed that R1DC25T represents a distinct lineage within the family Parvibaculaceae in the order Rhizobiales within the class Alphaproteobacteria. R1DC25T showing 95.8, 95.3 and 94.5 % 16S rRNA gene sequence identity with Rhodoligotrophos appendicifer, Rhodoligotrophos jinshengii and Rhodoligotrophos defluvii, respectively. The predominant quinone was Q-10, and the polar lipids were phosphatidylglycerol, phosphatidylcholine, diphosphatidylglycerol, as well as several distinct aminolipids and lipids. The predominant cellular fatty acids were C19 : 0 cyclo ω8c, a combination of C18 : 1 ω7c and/or C18 : 1 ω6c and C16 : 0. On the basis of the differences in the phenotypic, physiological and biochemical characteristics from its known relatives and the results of our phylogenetic analyses, R1DC25T (=KCTC 72348T;=JCM 33619T;=NCCB 100699T) is proposed to represent a novel species in a novel genus, and we propose the name Kaustia mangrovi gen. nov., sp. nov. (Kaustia, subjective name derived from the abbreviation KAUST for King Abdullah University of Science and Technology; mangrovi, of a mangrove).


Assuntos
Alphaproteobacteria/classificação , Filogenia , Rhizophoraceae/microbiologia , Áreas Alagadas , Alphaproteobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Oceano Índico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Arábia Saudita , Análise de Sequência de DNA , Ubiquinona/análogos & derivados , Ubiquinona/química
20.
Microbiol Res ; 250: 126788, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34051611

RESUMO

The symbiosis between legumes and nodulating Proteobacteria (so-called rhizobia) contributes greatly to nitrogen fixation in terrestrial ecosystems. Root nodulating Proteobacteria produce nodulation (Nod) factors during the initiation of rhizobial nodule organogenesis on the roots of legumes. Here, we screened the Nod factor production capacity of the previously reported nodule inducing Proteobacteria genera using their genome sequences and assessed the evolutionary history of symbiosis based on phylogenomics. Our analysis revealed 12 genera as potentially Nod factor producing taxa exclusively from alpha- and beta-Proteobacteria. Based on molecular clock analysis, we estimate that rhizobial nitrogen-fixing symbiosis appeared for the first time about 51 Mya (Eocene epoch) in Rhizobiaceae, and it was laterally transferred to multiple symbiotic taxa in alpha- and beta-Proteobacteria. Coevolutionary tests conducted for measuring the phylogenetic congruence between hosts and symbionts revealed only weak topological similarity between legumes and their bacterial symbionts. We conclude that frequent lateral transfer of symbiotic genes, facultative symbiotic nature of rhizobia, differential evolutionary processes of chromosome versus plasmids, and complex multispecies coevolutionary processes have shaped the rhizobia-host associations.


Assuntos
Alphaproteobacteria/genética , Betaproteobacteria/genética , Filogenia , Nodulação/genética , Rhizobium/genética , Simbiose/genética , Ecossistema , Fabaceae/microbiologia , Transferência Genética Horizontal , Mimosa/microbiologia , Fixação de Nitrogênio , Rhizobium/classificação
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