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1.
Front Immunol ; 12: 733064, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34616401

RESUMEN

Bacterial outer membrane vesicles (OMVs) are nanometer-scale, spherical vehicles released by Gram-negative bacteria into their surroundings throughout growth. These OMVs have been demonstrated to play key roles in pathogenesis by delivering certain biomolecules to host cells, including toxins and other virulence factors. In addition, this biomolecular delivery function enables OMVs to facilitate intra-bacterial communication processes, such as quorum sensing and horizontal gene transfer. The unique ability of OMVs to deliver large biomolecules across the complex Gram-negative cell envelope has inspired the use of OMVs as antibiotic delivery vehicles to overcome transport limitations. In this review, we describe the advantages, applications, and biotechnological challenges of using OMVs as antibiotic delivery vehicles, studying both natural and engineered antibiotic applications of OMVs. We argue that OMVs hold great promise as antibiotic delivery vehicles, an urgently needed application to combat the growing threat of antibiotic resistance.


Asunto(s)
Antibacterianos/administración & dosificación , Membrana Externa Bacteriana/metabolismo , Portadores de Fármacos , Vesículas Extracelulares/metabolismo , Bacterias Aerobias Gramnegativas/metabolismo , Animales , Antibacterianos/metabolismo , Composición de Medicamentos , Vesículas Extracelulares/genética , Bacterias Aerobias Gramnegativas/genética , Humanos
2.
Microb Drug Resist ; 27(1): 18-24, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32522076

RESUMEN

The spreading of carbapenemase-producing gram-negative bacilli (GNB) must be considered as an "urgent" threat. The aim of this study was to determine the prevalence of extended spectrum ß-lactamase (ESBL), plasmid-mediated quinolone resistance (PMQR), and carbapenemase-producing GNB and to characterize the supporting genes in GNB specimens isolated from patients and healthy volunteers in Burkina Faso. From April to June 2016, carbapenemase-producing GNB screening was performed in 1,230 consecutive clinical specimens, and 158 fecal samples from inpatients and healthy volunteers without digestive pathology at Souro Sanou University Hospital, Bobo Dioulasso. Strains were identified by matrix-assisted laser desorption ionization-time of flight and antimicrobial susceptibility was tested with the disk diffusion method on Müller-Hinton agar. The presence of carbapenemase, ESBL, and PMQR genes was assessed by multiplex PCR. The molecular epidemiological study was performed using multilocus sequence typing analysis. From the 1,230 clinical samples, 443 GNB strains were isolated among which 4 (0.9%) were carbapenemase-producing isolates (Escherichia coli, n = 1; Acinetobacter baumannii, n = 3). Among the 158 fecal samples tested for carbapenemase-producing Enterobacteriaceae carriage, 13 (8.2%) were carbapenemase-producing isolates (E. coli, n = 4; Klebsiella pneumoniae, n = 6; A. baumannii, n = 2; Acinetobacter nosocomialis, n = 1; Acinetobacter bereziniae, n = 1). The strains from the two groups were resistant to broad-spectrum cephalosporins (100% for both), gentamicin (100% and 64.3%), levofloxacin (100% and 85.7%), and to amikacin (0% and 7.1%). The carbapenemase-encoding genes blaNDM-1, blaOxa-58, blaOxa-181, and blaVIM-2 were detected in clinical and in fecal samples. The majority (10/11) of the enterobacterial strains carried also blaCTX-M-15. The majority of the strains belonged to ST692 for E. coli, to ST147 for K. pneumoniae and to ST2 for A. baumannii. This study confirms the presence of carbapenemase-producing GNB in samples from patients and healthy volunteers. More effective active surveillance activities are needed.


Asunto(s)
Antibacterianos/farmacología , Bacterias Aerobias Gramnegativas/efectos de los fármacos , Bacterias Aerobias Gramnegativas/genética , Infecciones por Bacterias Gramnegativas/epidemiología , beta-Lactamasas/genética , Proteínas Bacterianas/genética , Burkina Faso/epidemiología , Relación Dosis-Respuesta a Droga , Farmacorresistencia Bacteriana Múltiple , Femenino , Fluoroquinolonas/farmacología , Infecciones por Bacterias Gramnegativas/genética , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Plásmidos/efectos de los fármacos , Reacción en Cadena de la Polimerasa
3.
Mol Biol Evol ; 38(3): 1040-1059, 2021 03 09.
Artículo en Inglés | MEDLINE | ID: mdl-33169788

RESUMEN

Achromatium is large, hyperpolyploid and the only known heterozygous bacterium. Single cells contain approximately 300 different chromosomes with allelic diversity far exceeding that typically harbored by single bacteria genera. Surveying all publicly available sediment sequence archives, we show that Achromatium is common worldwide, spanning temperature, salinity, pH, and depth ranges normally resulting in bacterial speciation. Although saline and freshwater Achromatium spp. appear phylogenetically separated, the genus Achromatium contains a globally identical, complete functional inventory regardless of habitat. Achromatium spp. cells from differing ecosystems (e.g., from freshwater to saline) are, unexpectedly, equally functionally equipped but differ in gene expression patterns by transcribing only relevant genes. We suggest that environmental adaptation occurs by increasing the copy number of relevant genes across the cell's hundreds of chromosomes, without losing irrelevant ones, thus maintaining the ability to survive in any ecosystem type. The functional versatility of Achromatium and its genomic features reveal alternative genetic and evolutionary mechanisms, expanding our understanding of the role and evolution of polyploidy in bacteria while challenging the bacterial species concept and drivers of bacterial speciation.


Asunto(s)
Evolución Biológica , Genoma Bacteriano , Sedimentos Geológicos/microbiología , Bacterias Aerobias Gramnegativas/genética , Microbiología del Agua , Ecosistema , Bacterias Aerobias Gramnegativas/metabolismo , Heterocigoto , Filogenia , Poliploidía
4.
Syst Appl Microbiol ; 43(5): 126129, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32847778

RESUMEN

Planctomycetes of the family Gemmataceae are characterized by large genome sizes and cosmopolitan distribution in freshwater and terrestrial environments but their ecological functions remain poorly understood. In this study, we characterized a novel representative of this family, strain PL17T, which was isolated from a littoral tundra wetland and was capable of growth on xylan and cellulose. Cells of this isolate were represented by pink-pigmented spheres that multiplied by budding and occurred singly or in short chains and aggregates. Strain PL17T was obligately aerobic, mildly acidophilic chemoorganotrophic bacterium, which displayed good tolerance of low temperatures. The major fatty acids were C18:0, C16:1ω5, and ßOH-C16:1; the major polar lipid was trimethylornithine. The genome of strain PL17T consisted of a 9.83 Mb chromosome and a 24.69kb plasmid. The G+C contents of the chromosomal and plasmid DNA were 67.4 and 62.3mol%, respectively. Over 8900 potential protein-coding genes were identified in the genome including a putative cellulase that contains a domain from the GH5 family of glycoside hydrolases. The genome of strain PL17T contained one linked and one unlinked rRNA operons with 16S rRNA gene sequences displaying 94.5% similarity to that in Gemmata obscuriglobus UQM2246T. Based on the results of comparative phenotypic, chemotaxonomic and phylogenomic analyses, we propose to classify strain PL17T (= CECT 9407T=VKM B-3467T) as representing a novel genus and species of the family Gemmataceae, Frigoriglobus tundricola gen. nov., sp. nov.


Asunto(s)
Bacterias Aerobias Gramnegativas/clasificación , Bacterias Aerobias Gramnegativas/aislamiento & purificación , Tundra , Humedales , Bacterias , Técnicas de Tipificación Bacteriana , Composición de Base , Celulosa/metabolismo , Frío , ADN Bacteriano/química , ADN Bacteriano/genética , Ácidos Grasos/análisis , Genes Bacterianos , Genes de ARNr , Genoma Bacteriano , Bacterias Aerobias Gramnegativas/genética , Bacterias Aerobias Gramnegativas/fisiología , Lípidos/análisis , Redes y Vías Metabólicas/genética , Filogenia , Planctomycetales/clasificación , Planctomycetales/genética , ARN Ribosómico 16S/genética , Xilanos/metabolismo
5.
FEMS Microbiol Ecol ; 95(8)2019 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-31295349

RESUMEN

Biological nitrogen fixation plays an important role in nitrogen cycling by transferring atmospheric N2 to plant-available N in the soil. However, the diazotrophic activity and distribution in different types of soils remain to be further explored. In this study, 152 upland soils were sampled to examine the diazotrophic abundance, nitrogenase activity, diversity and community composition by quantitative polymerase chain reaction, acetylene reduction assay and the MiSeq sequencing of nifH genes, respectively. The results showed that diazotrophic abundance and nitrogenase activity varied among the three soil types. The diazotrophic community was mainly dominated by Bradyrhizobium, Azospirillum, Myxobacter, Desulfovibrio and Methylobacterium. The symbiotic diazotroph Bradyrhizobium was widely distributed among soils, while the distribution of free-living diazotrophs showed large variation and was greatly affected by multiple factors. Crop type and soil properties directly affected the diazotrophic ɑ-diversity, while soil properties, climatic factors and spatial distance together influenced the diazotrophic community. Network structures were completely different among all three types of soils, with most complex interactions observed in the Red soil. These findings suggest that diazotrophs have various activities and distributions in the three soil types, which played different roles in nitrogen input in agricultural soil in China, being driven by multiple environmental factors.


Asunto(s)
Bacterias Aerobias Gramnegativas/metabolismo , Bacterias Anaerobias Gramnegativas/metabolismo , Fijación del Nitrógeno/fisiología , Oxidorreductasas/genética , Microbiología del Suelo , Agricultura , Bradyrhizobium , China , Granjas , Bacterias Aerobias Gramnegativas/clasificación , Bacterias Aerobias Gramnegativas/genética , Bacterias Anaerobias Gramnegativas/clasificación , Bacterias Anaerobias Gramnegativas/genética , Nitrógeno/análisis , Suelo/química , Simbiosis
6.
Curr Microbiol ; 75(12): 1584-1588, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30238241

RESUMEN

A Gram-negative, yellow-pigmented, aerobic bacterium, designated strain B51-30T, was isolated from oil-well production liquid in Baolige oilfield, China. The strain was able to grow at pH 6-10 (optimum at pH 7.5), in 0-6% (w/v) NaCl (optimum at 1%, w/v) at 15-55 °C (optimum at 45 °C). Cells of the isolate were non-motile and non-spore-forming rods. The major cellular fatty acids were iso-C15:0, iso-C11:0, iso-C11:0 3OH, iso-C17:1 ω9c, and iso-C17:0. Ubiquinone 8 was the predominant respiratory quinone. The major polar lipids consisted of phosphatidylethanolamine and diphosphatidylglycerol. The genomic DNA G+C content of the isolate was 70.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain B51-30T was most closely related to Coralloluteibacterium stylophorae KCTC 52167T (98.7% similarity). The two strains showed DNA-DNA relatedness values of 58.5%. Genotypic and phenotypic features indicate that strain B51-30T represents a novel species of the genus Coralloluteibacterium, for which the name Coralloluteibacterium thermophilus sp. nov. is proposed. The type strain is B51-30T (= CGMCC 1.13574T = KCTC 62780T).


Asunto(s)
Gammaproteobacteria/aislamiento & purificación , Bacterias Aerobias Gramnegativas/aislamiento & purificación , Yacimiento de Petróleo y Gas/microbiología , Técnicas de Tipificación Bacteriana/métodos , Composición de Base/genética , China , ADN Bacteriano/genética , Ácidos Grasos/genética , Gammaproteobacteria/genética , Bacterias Aerobias Gramnegativas/genética , Fosfolípidos/genética , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN/métodos , Microbiología del Suelo
7.
Antonie Van Leeuwenhoek ; 111(10): 1845-1853, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29603043

RESUMEN

A Gram-stain negative, aerobic, rod-shaped, non-motile, yellow-pigmented and non-spore-forming bacterial strain, designated PM5-8T, was isolated from a culture of a marine toxigenic dinoflagellate Prorocentrum mexicanum PM01. Strain PM5-8T grew at 15-35 °C (optimum, 25-30 °C) and pH 6-11 (optimum, 7.5-8). Cells required at least 1.5% (w/v) NaCl for growth, and can tolerate up to 7.0% with the optimum of 4%. Phylogenetic analysis based on 16S rRNA gene sequence revealed that the strain PM5-8T is closely related to members of the genus Hoeflea, with high sequence similarities with Hoeflea halophila JG120-1T (97.06%) and Hoeflea alexandrii AM1V30T (97.01%). DNA-DNA hybridization values between the isolate and other type strains of recognized species of the genus Hoeflea were between 11.8 and 25.2%, which is far below the value of 70% threshold for species delineation. The DNA G + C content was 50.3 mol%. The predominant cellular fatty acids of the strain were identified as summed feature 8 (C16:1 ω7c and/or C16:1 ω6c; 51.5%), C18:1 ω7c 11-methyl (20.7%), C16:0 (17.2%) and C18:0 (5.7%). The major respiratory quinone was Q-10. Polar lipids profiles contained phosphatidylcholine, phosphatidylglycerol, sulfoquinovosyl diacylglycerol, phosphatidylmono- methylethanolamine, phosphatidylethanolamine and four unidentified lipids. On the basis of the polyphasic taxonomic data presented, strain PM5-8T (= CCTCC AB 2016294T = KCTC 62490T) represents a novel species of the genus Hoeflea, for which the name Hoeflea prorocentri sp. nov. is proposed.


Asunto(s)
Organismos Acuáticos/microbiología , Dinoflagelados/microbiología , Bacterias Aerobias Gramnegativas/clasificación , ADN Bacteriano , Bacterias Aerobias Gramnegativas/química , Bacterias Aerobias Gramnegativas/genética , Bacterias Aerobias Gramnegativas/aislamiento & purificación , Metabolómica/métodos , Tipificación Molecular , Fenotipo , Filogenia , ARN Ribosómico 16S/genética
8.
Microb Ecol ; 76(3): 584-587, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29492594

RESUMEN

Achromatium is the largest freshwater bacterium known to date and easily recognised by conspicuous calcite bodies filling the cell volume. Members of this genus are highly abundant in diverse aquatic sediments and may account for up to 90% of the bacterial biovolume in the oxic-anoxic interfaces. The high abundance implies that Achromatium is either rapidly growing or hardly prone to predation. As Achromatium is still uncultivated and does not appear to grow fast, one could assume that the cells might escape predation by their unusual shape and composition. However, we observed various members of the meiofauna grazing or parasitizing on Achromatium. By microphotography, we documented amoebae, ciliates, oligochetes and plathelminthes having Achromatium cells ingested. Some Achromatium cells harboured structures resembling sporangia of parasitic fungi (chytrids) that could be stained with the chitin-specific dye Calcofluor White. Many Achromatia carried prokaryotic epibionts in the slime layer surrounding the cells. Their regular distribution over the cell might indicate that they are commensalistic rather than harming their hosts. In conclusion, we report on various interactions of Achromatium with the sediment community and show that although Achromatium cells are a crispy diet, full of calcite bodies, predators do not spare them.


Asunto(s)
Sedimentos Geológicos/microbiología , Bacterias Aerobias Gramnegativas/crecimiento & desarrollo , Lagos/microbiología , Amoeba/fisiología , Animales , Cilióforos/fisiología , Sedimentos Geológicos/parasitología , Bacterias Aerobias Gramnegativas/clasificación , Bacterias Aerobias Gramnegativas/genética , Bacterias Aerobias Gramnegativas/aislamiento & purificación , Lagos/parasitología , Oligoquetos/fisiología
9.
Nat Commun ; 8(1): 455, 2017 09 06.
Artículo en Inglés | MEDLINE | ID: mdl-28878209

RESUMEN

Polyploid bacteria are common, but the genetic and functional diversity resulting from polyploidy is unknown. Here we use single-cell genomics, metagenomics, single-cell amplicon sequencing, and fluorescence in situ hybridization, to show that individual cells of Achromatium oxaliferum, the world's biggest known freshwater bacterium, harbor genetic diversity typical of whole bacterial communities. The cells contain tens of transposable elements, which likely cause the unprecedented diversity that we observe in the sequence and synteny of genes. Given the high within-cell diversity of the usually conserved 16S ribosomal RNA gene, we suggest that gene conversion occurs in multiple, separated genomic hotspots. The ribosomal RNA distribution inside the cells hints to spatially differential gene expression. We also suggest that intracellular gene transfer may lead to extensive gene reshuffling and increased diversity.The cells of Achromatium bacteria are remarkably large and contain multiple chromosome copies. Here, Ionescu et al. show that chromosome copies within individual cells display high diversity, similar to that of bacterial communities, and contain tens of transposable elements.


Asunto(s)
Genoma Bacteriano , Bacterias Aerobias Gramnegativas/citología , Bacterias Aerobias Gramnegativas/genética , Azufre/metabolismo , Evolución Biológica , Cromosomas Bacterianos/genética , Regulación Bacteriana de la Expresión Génica , Técnicas de Transferencia de Gen , Variación Genética , Bacterias Aerobias Gramnegativas/ultraestructura , Hibridación Fluorescente in Situ , Funciones de Verosimilitud , Metagenómica , Modelos Genéticos , Operón/genética , Poliploidía , ARN Ribosómico 16S/genética , Sintenía/genética
10.
Curr Microbiol ; 74(3): 404-412, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28184991

RESUMEN

Two closely related aerobic, Gram reaction-negative rod-shaped bacteria (S7-75T and S7-80) were isolated from mucus of coral Fungia seychellensis from Andaman Sea, India. Heterotrophic growth on marine agar was observed at 4-35 °C and pH 6.5-10.5; optimum growth occurred at 25-30 °C and pH 7-8. 16 S rRNA sequence analysis confirmed the strains belonged to the genus Sulfitobacter and the two isolates shared more than 99.28% pairwise sequence similarity. DNA-DNA similarity between two isolates S7-75T and S7-80 was above 96%. Strain S7-75T showed maximum 16S rRNA similarity of 99.64% with Sulfitobacter pontiacus LMG 19752T. However, DNA-DNA relatedness between strain S7-75T and S. pontiacus LMG 19752T confirmed the placement of strain S7-75T as subspecies under the species S. pontiacus. Further, pulsed-field gel electrophoresis (PFGE), REP-PCR, ERIC-PCR fingerprint patterns and lipid profiles also differentiated strain S7-75T from the reference strain of S. pontiacus LMG 19752T. The DNA G+C content was 59.8 mol%. Q10 was the major respiratory quinone. Based on polyphasic analysis, the isolate S7-75T represents a subspecies of S. pontiacus for which the name S. pontiacus subsp. fungiae subsp. nov. is proposed with S7-75T (=JCM 31094T = LMG 29158T) as type strain.


Asunto(s)
Antozoos/microbiología , Bacterias Aerobias Gramnegativas/genética , Animales , Composición de Base/genética , ADN Bacteriano/genética , ADN Ribosómico/genética , Bacterias Aerobias Gramnegativas/clasificación , Rhodobacteraceae/clasificación , Rhodobacteraceae/genética
11.
Curr Microbiol ; 72(6): 752-7, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26920869

RESUMEN

A Gram-negative bacterium, denoted JLT2012(T), was isolated from the surface water of the Pacific Ocean. This aerobic bacterium was rod shaped and devoid of flagella, displayed gliding motility, and grew in characteristic orange colonies. The bacterium contained ubiquinone Q-10 as the major respiratory quinone, and spermidine and spermine as the major polyamine compounds. The dominant fatty acids were C18:1ω7c and/or C18:1ω6c (34.7 %), C16:0 (21.3 %), and C18:0 (15.9 %), whereas the polar lipids consisted mainly of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, four sphingoglycolipids, and several unknown glycolipids. The G + C content DNA was found to be 65.5 mol%. Comparative 16S rRNA gene sequence analysis revealed that strain JLT2012(T) formed a distinct lineage within the genus Pacificimonas (formerly known as Pacificamonas) and shared the highest sequence similarity with the type strain of Pacificimonas flava JLT2015(T) (96.0 %). Data combined from different studies on the phenotypic, phylogenetic, and genomic characteristics indicated that strain JLT2012(T) is a representative of a novel species within Pacificimonas for which the name Pacificimonas aurantium sp. nov. (type strain JLT2012(T)=LMG 27361(T)=CGMCC 1.12399(T)) is proposed.


Asunto(s)
Bacterias Aerobias Gramnegativas/aislamiento & purificación , Agua de Mar/microbiología , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/química , Ácidos Grasos/metabolismo , Bacterias Aerobias Gramnegativas/clasificación , Bacterias Aerobias Gramnegativas/genética , Bacterias Aerobias Gramnegativas/metabolismo , Océano Pacífico , Filogenia , ARN Ribosómico 16S/genética
12.
PLoS One ; 10(11): e0141350, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26529504

RESUMEN

The prompt and accurate identification of bacterial pathogens is fundamental to patient health and outcome. Recent advances in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) have revolutionized bacterial identification in the clinical laboratory, but uniform incorporation of this technology in the U.S. market has been delayed by a lack of FDA-cleared systems. In this study, we conducted a multicenter evaluation of the MALDI Biotyper CA (MBT-CA) System (Bruker Daltonics Inc, Billerica, MA) for the identification of aerobic gram-negative bacteria as part of a 510(k) submission to the FDA. A total of 2,263 aerobic gram negative bacterial isolates were tested representing 23 genera and 61 species. Isolates were collected from various clinical sources and results obtained from the MBT-CA System were compared to DNA sequencing and/or biochemical testing. Isolates that failed to report as a "high confidence species ID" [log(score) ≥2.00] were re-tested using an extraction method. The MBT-CA System identified 96.8% and 3.1% of isolates with either a "high confidence" or a "low confidence" [log(score) value between 1.70 and <2.00] species ID, respectively. Two isolates did not produce acceptable confidence scores after extraction. The MBT-CA System correctly identified 99.8% (2,258/2,263) to genus and 98.2% (2,222/2,263) to species level. These data demonstrate that the MBT-CA System provides accurate results for the identification of aerobic gram-negative bacteria.


Asunto(s)
Técnicas de Tipificación Bacteriana , Bacterias Aerobias Gramnegativas/clasificación , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Técnicas de Tipificación Bacteriana/instrumentación , Técnicas de Tipificación Bacteriana/métodos , Bacterias Aerobias Gramnegativas/genética , Humanos , Sensibilidad y Especificidad , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/instrumentación , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos
13.
Mar Genomics ; 24 Pt 3: 277-80, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26411640

RESUMEN

Wenzhouxiangella marina is an obligatory aerobic, Gram-negative, non-motile, rod-shaped bacterium that was isolated from the culture broth of marine microalgae, Picochlorum sp. 122. Here we report the 3.67 MB complete genome (65.26 G+C%) of W. marina KCTC 42284(T) encoding 3,016 protein-coding genes, 43 tRNAs and one rRNA operon. The genomic information supports multiple horizontal gene transfer (HGT) events in the history of W. marina, possibly with other marine bacteria co-existing in marine habitats. Evaluation of genomic signatures revealed 19 such HGT-derived genomic islands. Of these, eight were also supported by "genomic context" that refers to the existence of integrases, transposases and tmRNA genes either inside or in near vicinity to the island. The addition of W. marina genome expands the repertoire of marine bacterial genomic diversity, especially because the strain represents the sole genomic resource of a novel taxonomic family in the bacterial order Chromatiales.


Asunto(s)
Bacterias Aerobias Gramnegativas/genética , Mapeo Cromosómico , Cromosomas Bacterianos , Regulación Bacteriana de la Expresión Génica , Microalgas/microbiología , ARN Bacteriano/genética
14.
ISME J ; 9(11): 2503-14, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25909974

RESUMEN

Large sulfur bacteria of the genus Achromatium are exceptional among Bacteria and Archaea as they can accumulate high amounts of internal calcite. Although known for more than 100 years, they remain uncultured, and only freshwater populations have been studied so far. Here we investigate a marine population of calcite-accumulating bacteria that is primarily found at the sediment surface of tide pools in a salt marsh, where high sulfide concentrations meet oversaturated oxygen concentrations during the day. Dynamic sulfur cycling by phototrophic sulfide-oxidizing and heterotrophic sulfate-reducing bacteria co-occurring in these sediments creates a highly sulfidic environment that we propose induces behavioral differences in the Achromatium population compared with reported migration patterns in a low-sulfide environment. Fluctuating intracellular calcium/sulfur ratios at different depths and times of day indicate a biochemical reaction of the salt marsh Achromatium to diurnal changes in sedimentary redox conditions. We correlate this calcite dynamic with new evidence regarding its formation/mobilization and suggest general implications as well as a possible biological function of calcite accumulation in large bacteria in the sediment environment that is governed by gradients. Finally, we propose a new taxonomic classification of the salt marsh Achromatium based on their adaptation to a significantly different habitat than their freshwater relatives, as indicated by their differential behavior as well as phylogenetic distance on 16S ribosomal RNA gene level. In future studies, whole-genome characterization and additional ecophysiological factors could further support the distinctive position of salt marsh Achromatium.


Asunto(s)
Carbonato de Calcio/química , Agua Dulce/microbiología , Bacterias Aerobias Gramnegativas/genética , Bacterias Reductoras del Azufre/genética , Microbiología del Agua , Humedales , Compuestos de Calcio , Gammaproteobacteria/genética , Massachusetts , Oxidación-Reducción , Filogenia , ARN Ribosómico 16S/genética , Cloruro de Sodio , Sulfuros , Azufre/química
15.
Jpn J Antibiot ; 65(1): 73-96, 2012 Feb.
Artículo en Japonés | MEDLINE | ID: mdl-22808694

RESUMEN

We determined MICs of antibacterial agents against 1145 clinical strains of aerobic Gram-negative bacteria (22 species) isolated at 16 Japanese facilities in 2008. MICs were determined using mostly broth microdilution method and antibacterial activity was assessed. Strains producing extended-spectrum beta-lactamases (ESBL) accounted for 3.8% of Escherichia coli, 2.6% of Klebsiella pneumoniae, 6.8% of Klebsiella oxytoca, 5.5% of Proteus mirabilis and 1.8% of Proteus vulgaris. ESBL produced strains were 6.8% at K. oxytoca that increased compared with 3.2% and 5.5% at P. mirabilis that decreased compared with 18.8% in 2006. Among Haemophilus influenzae, 61.7% that decreased compared with 67.7% in 2006, equaled 58.7% in 2004, were strains when classified by penicillin-binding protein 3 mutation. Against Pseudomonas aeruginosa, the activity of most antibacterial agents was similar to that in 2006. Although two antibacterial agents that tobramycin showed an MIC90 of 1 microg/mL and doripenem showed an MIC90 of 4 microg/mL against P. aeruginosa have potent activity. Of all P. aeruginosa strains, 4.3% were resistant to six agents of nine antipseudomonal agents, that decreased compared to 12.2% in 2004 and 5.7% in 2006. Against other glucose-non-fermentative Gram-negative rods, the activity of most antibacterial agents was similar to that in 2006.


Asunto(s)
Antibacterianos/farmacología , Bacterias Aerobias Gramnegativas/efectos de los fármacos , Farmacorresistencia Bacteriana , Bacterias Aerobias Gramnegativas/genética , Humanos , Pruebas de Sensibilidad Microbiana , Mutación , Proteínas de Unión a las Penicilinas/genética
16.
J Bacteriol ; 194(14): 3731, 2012 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-22740661

RESUMEN

We report the 3.087-Mb genome sequence of Imtechella halotolerans K1(T), isolated from an estuarine water sample collected from Kochi, Kerala, India. Strain K1 was recently reported as a novel genus of the family Flavobacteriaceae.


Asunto(s)
Genoma Bacteriano , Bacterias Aerobias Gramnegativas/genética , Regulación Bacteriana de la Expresión Génica , Datos de Secuencia Molecular
18.
Appl Microbiol Biotechnol ; 92(6): 1095-105, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22031465

RESUMEN

Microbial metabolism of furanic compounds, especially furfural and 5-hydroxymethylfurfural (HMF), is rapidly gaining interest in the scientific community. This interest can largely be attributed to the occurrence of toxic furanic aldehydes in lignocellulosic hydrolysates. However, these compounds are also widespread in nature and in human processed foods, and are produced in industry. Although several microorganisms are known to degrade furanic compounds, the variety of species is limited mostly to Gram-negative aerobic bacteria, with a few notable exceptions. Furanic aldehydes are highly toxic to microorganisms, which have evolved a wide variety of defense mechanisms, such as the oxidation and/or reduction to the furanic alcohol and acid forms. These oxidation/reduction reactions constitute the initial steps of the biological pathways for furfural and HMF degradation. Furfural degradation proceeds via 2-furoic acid, which is metabolized to the primary intermediate 2-oxoglutarate. HMF is converted, via 2,5-furandicarboxylic acid, into 2-furoic acid. The enzymes in these HMF/furfural degradation pathways are encoded by eight hmf genes, organized in two distinct clusters in Cupriavidus basilensis HMF14. The organization of the five genes of the furfural degradation cluster is highly conserved among microorganisms capable of degrading furfural, while the three genes constituting the initial HMF degradation route are organized in a highly diverse manner. The genetic and biochemical characterization of the microbial metabolism of furanic compounds holds great promises for industrial applications such as the biodetoxifcation of lignocellulosic hydrolysates and the production of value-added compounds such as 2,5-furandicarboxylic acid.


Asunto(s)
Furaldehído/metabolismo , Bacterias Aerobias Gramnegativas/genética , Bacterias Aerobias Gramnegativas/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Bioquímica , Humanos
19.
Int J Food Microbiol ; 147(3): 217-22, 2011 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-21543129

RESUMEN

The 16S-23S gene internal transcribed spacer sequence of sixty-four strains belonging to different acetic acid bacteria genera were analyzed, and phylogenetic trees were generated for each genera. The topologies of the different trees were in accordance with the 16S rRNA gene trees, although the similarity percentages obtained between the species was shown to be much lower. These values suggest the usefulness of including the 16S-23S gene internal transcribed spacer region as a part of the polyphasic approach required for the further classification of acetic acid bacteria. Furthermore, the region could be a good target for primer and probe design. It has also been validated for use in the identification of unknown samples of this bacterial group from wine vinegar and fruit condiments.


Asunto(s)
Ácido Acético , Bacterias Aerobias Gramnegativas/genética , Técnicas de Tipificación Bacteriana , Secuencia de Bases , Microbiología de Alimentos , Genes de ARNr , Bacterias Aerobias Gramnegativas/clasificación , Datos de Secuencia Molecular , Filogenia , ARN Ribosómico 16S , ARN Ribosómico 23S , Análisis de Secuencia de ARN
20.
Int J Syst Evol Microbiol ; 61(Pt 8): 1837-1841, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20817839

RESUMEN

A Gram-negative, non-spore-forming, endophytic bacterium, strain YC6886(T), was isolated from the root of a halophyte, Rosa rugosa, which inhabits coastal areas of Namhae Island off the southern coast of Korea. Cells were non-motile, obligately aerobic rods and formed pale-yellow colonies. The isolate grew at 4-32 °C (optimum 25-28 °C) and at pH 6.5-9.5 (optimum pH 7.5) and grew optimally with 2-3 % (w/v) NaCl, but NaCl was not an absolute requirement for growth. Strain YC6886(T) produced yellow carotenoid pigments. Strain YC6886(T) exhibited the highest 16S rRNA gene sequence similarity with Haloferula sargassicola MN1-1037(T) (97.4 %). Sequence similarities between strain YC6886(T) and other members of the genus Haloferula were 93.9-94.7 %. DNA-DNA relatedness between strain YC6886(T) and H. sargassicola KCTC 22202(T) and Haloferula rosea KCTC 22201(T) was 27 and 15 %, respectively. The major fatty acids were iso-C(14 : 0), C(16 : 0) and C(16 : 1)ω9c and minor components were C(14 : 0), C(18 : 0) and anteiso-C(15 : 0). The major respiratory quinone was menaquinone 9 and the DNA G+C content was 58.5 mol%. The polar lipid profile was composed of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unknown phospholipid and an unknown phosphoglycolipid. On the basis of phenotypic, chemotaxonomic, DNA-DNA hybridization and phylogenetic analysis, strain YC6886(T) represents a novel species in the genus Haloferula, for which the name Haloferula luteola sp. nov. is proposed. The type strain is YC6886(T) ( = KCTC 22447(T)  = DSM 21608(T)). An emended description of the genus Haloferula is also presented.


Asunto(s)
Bacterias Aerobias Gramnegativas/clasificación , Bacterias Aerobias Gramnegativas/aislamiento & purificación , Raíces de Plantas/microbiología , Rosa/microbiología , ADN Bacteriano/genética , ADN Ribosómico/genética , Ácidos Grasos/metabolismo , Bacterias Aerobias Gramnegativas/genética , Bacterias Aerobias Gramnegativas/metabolismo , Datos de Secuencia Molecular , Filogenia , ARN Ribosómico 16S/genética
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