RESUMO
Bacteria of the genus Brucella are facultative intracellular parasites that cause brucellosis, a severe animal and human disease. Recently, a group of taxonomists merged the brucellae with the primarily free-living, phylogenetically related Ochrobactrum spp. in the genus Brucella. This change, founded only on global genomic analysis and the fortuitous isolation of some opportunistic Ochrobactrum spp. from medically compromised patients, has been automatically included in culture collections and databases. We argue that clinical and environmental microbiologists should not accept this nomenclature, and we advise against its use because (i) it was presented without in-depth phylogenetic analyses and did not consider alternative taxonomic solutions; (ii) it was launched without the input of experts in brucellosis or Ochrobactrum; (iii) it applies a non-consensus genus concept that disregards taxonomically relevant differences in structure, physiology, population structure, core-pangenome assemblies, genome structure, genomic traits, clinical features, treatment, prevention, diagnosis, genus description rules, and, above all, pathogenicity; and (iv) placing these two bacterial groups in the same genus creates risks for veterinarians, medical doctors, clinical laboratories, health authorities, and legislators who deal with brucellosis, a disease that is particularly relevant in low- and middle-income countries. Based on all this information, we urge microbiologists, bacterial collections, genomic databases, journals, and public health boards to keep the Brucella and Ochrobactrum genera separate to avoid further bewilderment and harm.
Assuntos
Brucella , Ochrobactrum , Ochrobactrum/classificação , Ochrobactrum/genética , Ochrobactrum/patogenicidade , Ochrobactrum/fisiologia , Brucella/classificação , Brucella/genética , Brucella/patogenicidade , Brucella/fisiologia , Terminologia como Assunto , Filogenia , Brucelose/tratamento farmacológico , Brucelose/microbiologia , Humanos , Infecções Oportunistas/microbiologiaRESUMO
The genus Ochrobactrum belongs to the family Brucellaceae and its members are known to be adapted to a wide range of ecological niches. Ochrobactrum anthropi ATCC 49188T and Ochrobactrum lupini LUP21T are strains isolated from human clinical and plant root nodule samples, respectively, which share high similarity for phylogenetic markers (i.e 100â% for 16S rRNA, 99.9â% for dnaK and 99.35â% for rpoB). In this work, multiple genome average nucleotide identity (ANI) approaches, digital DNA-DNA hybridization (dDDH) and phylogenetic analysis were performed in order to investigate the taxonomic relationship between O. anthropi ATCC 49188T, O. lupini LUP21T, and other five type strains from the genus Ochrobactrum. Whole-genome comparisons demonstrated that O. lupini LUP21T and the Ochrobactrum genus type species, O. anthropi ATCC 49188T, share 97.55â% of ANIb, 98.25â% of ANIm, 97.99â% of gANI, 97.94â% of OrthoANI and 83.9â% of dDDH, which exceed the species delineation thresholds. These strains are also closely related in phylogenies reconstructed from a concatenation of 1193 sequences from single-copy ortholog genes. A review of their profiles revealed that O. anthropi ATCC 49188T and O. lupini LUP21T do not present pronounced differences at phenotypic and chemotaxonomic levels. Considering phylogenetic, genomic, phenotypic and chemotaxonomic data, O. lupini should be considered a later heterotypic synonym of O. anthropi.
Assuntos
Ochrobactrum anthropi/classificação , Ochrobactrum/classificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Humanos , Hibridização de Ácido Nucleico , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
The aim of this work was to clarify the mechanism related to plant growth promoting of a bacterial strain (L115) isolated from Arachis hypogaea rhizospheres and the effects of high growth temperature and salinity on phospholipids and fatty acids composition. L115 was isolated from peanut rhizospheres and identified according to the sequence analysis of the 16S rRNA gene. Phenotypic, metabolic and plant growth promoting rhizobacteria (PGPR) characteristics of L115 were tested. Inoculation test in plant growth chamber was performed. In addition, L115 was exposed to a 37 °C and 300 mM NaCl and phospholipids and fatty acid composition were evaluated. L115 strain was identified as Ochrobactrum intermedium and was able to increase the peanut shoot and root length as well as dry weight, indicating a PGPR role by being able to produce indole acetic acid and siderophores and present ACC deaminase activity. In addition, L115 showed tolerance to both high growth temperature and 300 mM NaCl. The most striking change was a decreased percentage of 18:1 fatty acid and an increase in 16:0 and 18:0 fatty acids, under high growth temperature or a combination of increased temperature and salinity. The most important change in phospholipid levels was an increase in phosphatidylcholine biosynthesis in all growth conditions. L115 can promote the growth of peanut and can tolerate high growth temperature and salinity modifying the fatty acid unsaturation degree and increasing phosphatidylcholine levels. This work is the first to report the importance of the genus Ochrobactrum as PGPR on peanut growth as well as on the metabolic behaviour against abiotic stresses that occur in soil. This knowledge will be useful for developing strategies to improve the growth of this bacterium under stress and to enhance its bioprocess for the production of inoculants.
Assuntos
Arachis/microbiologia , Lipídeos/química , Ochrobactrum/isolamento & purificação , Ochrobactrum/metabolismo , Microbiologia do Solo , Arachis/crescimento & desenvolvimento , Argentina , Ácidos Indolacéticos/metabolismo , Metabolismo dos Lipídeos , Dados de Sequência Molecular , Ochrobactrum/classificação , Ochrobactrum/genética , Filogenia , Rizosfera , Salinidade , Cloreto de Sódio/análise , Cloreto de Sódio/metabolismo , Solo/química , TemperaturaRESUMO
Metal nanoparticle synthesis is an interesting area in nanotechnology due to their remarkable optical, magnetic, electrical, catalytic and biomedical properties, but there needs to develop clean, non-toxic and environmental friendly methods for the synthesis and assembly of nanoparticles. Biological agents in the form of microbes have emerged up as efficient candidates for nanoparticle synthesis due to their extreme versatility to synthesize diverse nanoparticles with varying size and shape. In the present study, an eco favorable method for the biosynthesis of silver nanoparticles using marine bacterial isolate has been attempted. Very interestingly, molecular identification proved it as a strain of Ochrobactrum anhtropi. In addition, the isolate was found to have the potential to form silver nanoparticles intracellularly at room temperature within 24 h. The biosynthesized silver nanoparticles were characterized by UV-Vis spectroscopy, transmission electron microscope (TEM) and scanning electron microscope (SEM). The UV-visible spectrum of the aqueous medium containing silver nanoparticles showed a peak at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. The SEM and TEM micrographs revealed that the synthesized silver nanoparticles were spherical in shape with a size range from 38 nm - 85 nm. The silver nanoparticles synthesized by the isolate were also used to explore its antibacterial potential against pathogens like Salmonella Typhi, Salmonella Paratyphi, Vibrio cholerae and Staphylococcus aureus.
Assuntos
Antibacterianos/farmacologia , Nanopartículas/metabolismo , Ochrobactrum/metabolismo , Prata/farmacologia , Antibacterianos/metabolismo , Organismos Aquáticos/classificação , Organismos Aquáticos/genética , Organismos Aquáticos/isolamento & purificação , Organismos Aquáticos/metabolismo , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Bactérias Gram-Negativas/efeitos dos fármacos , Microscopia Eletrônica , Nanopartículas/química , Nanopartículas/ultraestrutura , Ochrobactrum/classificação , Ochrobactrum/genética , Ochrobactrum/isolamento & purificação , Filogenia , /genética , Análise de Sequência de DNA , Análise Espectral , Prata/metabolismo , Staphylococcus aureus/efeitos dos fármacos , Temperatura , Fatores de TempoRESUMO
Metal nanoparticle synthesis is an interesting area in nanotechnology due to their remarkable optical, magnetic, electrical, catalytic and biomedical properties, but there needs to develop clean, non-toxic and environmental friendly methods for the synthesis and assembly of nanoparticles. Biological agents in the form of microbes have emerged up as efficient candidates for nanoparticle synthesis due to their extreme versatility to synthesize diverse nanoparticles with varying size and shape. In the present study, an eco favorable method for the biosynthesis of silver nanoparticles using marine bacterial isolate has been attempted. Very interestingly, molecular identification proved it as a strain of Ochrobactrum anhtropi. In addition, the isolate was found to have the potential to form silver nanoparticles intracellularly at room temperature within 24 h. The biosynthesized silver nanoparticles were characterized by UV-Vis spectroscopy, transmission electron microscope (TEM) and scanning electron microscope (SEM). The UV-visible spectrum of the aqueous medium containing silver nanoparticles showed a peak at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. The SEM and TEM micrographs revealed that the synthesized silver nanoparticles were spherical in shape with a size range from 38 nm - 85 nm. The silver nanoparticles synthesized by the isolate were also used to explore its antibacterial potential against pathogens like Salmonella Typhi, Salmonella Paratyphi, Vibrio cholerae and Staphylococcus aureus.
Assuntos
Antibacterianos/farmacologia , Nanopartículas/metabolismo , Ochrobactrum/metabolismo , Prata/farmacologia , Antibacterianos/metabolismo , Organismos Aquáticos/classificação , Organismos Aquáticos/genética , Análise por Conglomerados , DNA Bacteriano/química , DNA Ribossômico/química , Bactérias Gram-Negativas/efeitos dos fármacos , Microscopia Eletrônica , Nanopartículas/química , Ochrobactrum/classificação , FilogeniaRESUMO
Metal nanoparticle synthesis is an interesting area in nanotechnology due to their remarkable optical, magnetic, electrical, catalytic and biomedical properties, but there needs to develop clean, non-toxic and environmental friendly methods for the synthesis and assembly of nanoparticles. Biological agents in the form of microbes have emerged up as efficient candidates for nanoparticle synthesis due to their extreme versatility to synthesize diverse nanoparticles with varying size and shape. In the present study, an eco favorable method for the biosynthesis of silver nanoparticles using marine bacterial isolate has been attempted. Very interestingly, molecular identification proved it as a strain of Ochrobactrum anhtropi. In addition, the isolate was found to have the potential to form silver nanoparticles intracellularly at room temperature within 24 h. The biosynthesized silver nanoparticles were characterized by UV-Vis spectroscopy, transmission electron microscope (TEM) and scanning electron microscope (SEM). The UV-visible spectrum of the aqueous medium containing silver nanoparticles showed a peak at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. The SEM and TEM micrographs revealed that the synthesized silver nanoparticles were spherical in shape with a size range from 38 nm - 85 nm. The silver nanoparticles synthesized by the isolate were also used to explore its antibacterial potential against pathogens like Salmonella Typhi, Salmonella Paratyphi, Vibrio cholerae and Staphylococcus aureus.