RESUMO
A novel actinobacterium, designated strain CMAA 1533T, was isolated from the rhizosphere of Deschampsia antarctica collected at King George Island, Antarctic Peninsula. Strain CMAA 1533T was found to grow over a wide range of temperatures (4-28 °C) and pH (4-10). Macroscopically, the colonies were observed to be circular shaped, smooth, brittle and opaque-cream on most of the culture media tested. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CMAA 1533T belongs to the family Nocardiaceae and forms a distinct phyletic line within the genus Rhodococcus. Sequence similarity calculations indicated that the novel strain is closely related to Rhodococcus degradans CCM 4446T, Rhodococcus erythropolis NBRC 15567T and Rhodococcus triatomae DSM 44892T (≤ 96.9%). The organism was found to contain meso-diaminopimelic acid, galactose and arabinose in whole cell hydrolysates. Its predominant isoprenologue was identified as MK-8(H2) and the polar lipids as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannosides. The major fatty acids were identified as Summed feature (C16:1 ω6c and/or C16:1 ω7c), C16:0, C18:1 ω9c and 10-methyl C18:0. The G+C content of genomic DNA was determined to be 65.5 mol%. Unlike the closely related type strains, CMAA 1533T can grow at 4 °C but not at 37 °C and was able to utilise adonitol and galactose as sole carbon sources. Based on phylogenetic, chemotaxonomic and physiological data, it is concluded that strain CMAA 1533T (= NRRL B-65465T = DSM 104532T) represents a new species of the genus Rhodococcus, for which the name Rhodococcus psychrotolerans sp. nov. is proposed.
Assuntos
Filogenia , Poaceae/microbiologia , Rizosfera , Rhodococcus/classificação , Microbiologia do Solo , Regiões Antárticas , Composição de Bases , Metabolismo dos Carboidratos , Ácido Diaminopimélico/análise , Ácidos Graxos/análise , Genoma Bacteriano/genética , Peptidoglicano/química , Fosfolipídeos/análise , RNA Ribossômico 16S/genética , Rhodococcus/química , Rhodococcus/genética , Rhodococcus/metabolismo , Especificidade da Espécie , Temperatura , Vitamina K 2/análogos & derivados , Vitamina K 2/análiseRESUMO
The "Cave of Crystals" (aka 'Naica') in Chihuahua Mexico is a natural unique subterranean ecosystem which mainly consists of crystals made of calcium sulfate. The main system of caves are found at a depth of 300 meters (m) below sea level with crystals that range in size from a few centimeters to 15 m. The crystals date from nearly 400,000 years old and are thought to be formed when the cave was fully covered by water. At present time, this place shows a nearly constant temperature of 55 °C over the year and a humidity of 100 % which makes this place incomparable and unbearable to animal and/or human life. In the present study, two actinobacterial groups were isolated from within this system of caves and subjected to a systematic study to establish their phylogenetic relationship to microorganisms belonging to this vast group of Gram positive bacteria. Phenotypic properties, chemotaxonomic and 16S rRNA gene sequencing show that the microorganisms are members of the family Pseudonocardiaceae and are most closely related to the genus Prauserella. The present study is the first to report the isolation and presence of Actinobacteria or any other microbial form of life in this exceptional place. Moreover, this unexpected biodiversity can also provide an insight of the antibiotic resistome present in the isolates reported in this study.
Assuntos
Actinobacteria/isolamento & purificação , Cavernas/microbiologia , Actinobacteria/classificação , Actinobacteria/efeitos dos fármacos , Actinobacteria/genética , Actinobacteria/crescimento & desenvolvimento , Actinobacteria/metabolismo , Antibacterianos/farmacologia , Composição de Bases , Sequência de Bases , Sulfato de Cálcio , Cristalização , DNA Bacteriano/genética , Ácido Diaminopimélico/análise , Ácidos Graxos/análise , Concentração de Íons de Hidrogênio , Lipídeos/análise , México , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Fenótipo , Filogenia , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Alinhamento de Sequência , Especificidade da Espécie , TemperaturaRESUMO
A Gram-stain-positive, non-spore-forming bacterium (GW5-5797(T)) was isolated on soil extract agar from sand collected at a depth of 5 m in the Caribbean Sea near Grenada. 16S rRNA gene sequence analysis and similarity studies showed that strain GW5-5797(T) belongs to the genus Nocardia, and is most closely related to Nocardia speluncae N2-11(T) (99.2% similarity) and Nocardia jinanensis 04-5195(T) (99.2%) and more distantly related to Nocardia rhamnosiphila 202GMO(T) (98.6%) and other Nocardia species. Strain GW5-5797(T) could be distinguished from all other recognized Nocardia species by sequence similarity values less than 98.5%. The peptidoglycan diamino acid was meso-diaminopimelic acid. Strain GW5-5797(T) exhibited a quinone system with the predominant compounds MK-8(H(4)ω-cyclo) and MK-8(H(2)). The polar lipid profile of GW5-5797(T) consisted of the major compounds diphosphatidylglycerol, phosphatidylethanolamine and an unidentified glycolipid, moderate amounts of phosphatidylinositol and a phosphatidylinositol mannoside and minor amounts of several lipids including a second phosphatidylinositol mannoside. The polyamine pattern contained the major compound spermine and moderate amounts of spermidine. The major fatty acids were C(16:0,) C(18:1)ω9c and 10-methyl C(18:0). These chemotaxonomic traits are in excellent agreement with those of other Nocardia species. The results of DNA-DNA hybridizations and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain GW5-5797(T) from the most closely related species, showing 16S rRNA gene sequence similarities >98.5%. Strain GW5-5797(T) therefore merits separate species status, and we propose the name Nocardia grenadensis sp. nov., with the type strain GW5-5797(T) (=CCUG 60970(T) =CIP 110294(T)).
Assuntos
Sedimentos Geológicos/microbiologia , Nocardia/classificação , Nocardia/isolamento & purificação , Água do Mar/microbiologia , Técnicas de Tipagem Bacteriana , Benzoquinonas/análise , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Ácido Diaminopimélico/análise , Ácidos Graxos/análise , Granada , Dados de Sequência Molecular , Nocardia/genética , Nocardia/fisiologia , Hibridização de Ácido Nucleico , Peptidoglicano/química , Fosfolipídeos/análise , Filogenia , Poliaminas/análise , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Dióxido de SilícioRESUMO
Mycobacterium leprae, an obligate intracellular pathogen, can be derived only from host tissue and thus affords the opportunity to study in vivo-expressed products responsible for the particular pathogenesis of leprosy. Despite considerable progress in the characterization of the proteins and secondary gene products of M. leprae, there is little information on the nature of the proteins associated with the cell envelope. M. leprae has been fractionated into its major subcellular components, cell wall, cytoplasmic membrane, and soluble cytosol. A number of biochemical markers, including diaminopimelic acid content, monosaccharide composition, mycolic acid, and glycolipid distribution, were applied to their characterization, and two-dimensional gel electrophoresis was used to map the component proteins. A total of 391 major proteins spots were resolved, and 8 proteins were identified based on their reactivity to a panel of monoclonal antibodies and/or relative pI size. Microsequencing of six protein spots present in the cell wall fraction allowed identification of new proteins, including the protein elongation factor EF-Tu and a homolog for the Mycobacterium tuberculosis MtrA response regulator. These results, together with previous studies, contribute to the progressive knowledge of the composition of the in vivo-expressed proteins of M. leprae.