RESUMEN
The taxonomic status, biotechnological and ecological potential of several Micromonospora strains isolated from an extreme hyper arid Atacama Desert soil were determined. Initially, a polyphasic study was undertaken to clarify the taxonomic status of five micromonosporae, strains LB4, LB19, LB32T, LB39T and LB41, isolated from an extreme hyper-arid soil collected from one of the driest regions of the Atacama Desert. All of the isolates were found to have chemotaxonomic, cultural and morphological properties consistent with their classification in the genus Micromonospora. Isolates LB32T and LB39T were distinguished from their nearest phylogenetic neighbours and proposed as new species, namely as Micromonospora arida sp. nov. and Micromonospora inaquosa sp. nov., respectively. Eluted methanol extracts of all of the isolates showed activity against a panel of bacterial and fungal indicator strains, notably against multi-drug resistant Klebsiella pneumoniae ATCC 700603 while isolates LB4 and LB41 showed pronounced anti-tumour activity against HepG2 cells. Draft genomes generated for the isolates revealed a rich source of novel biosynthetic gene clusters, some of which were unique to individual strains thereby opening up the prospect of selecting especially gifted micromonosporae for natural product discovery. Key stress-related genes detected in the genomes of all of the isolates provided an insight into how micromonosporae adapt to the harsh environmental conditions that prevail in extreme hyper-arid Atacama Desert soils.
Asunto(s)
Antiinfecciosos/aislamiento & purificación , Antineoplásicos/aislamiento & purificación , Infecciones por Klebsiella/terapia , Klebsiella pneumoniae/fisiología , Neoplasias Hepáticas/terapia , Metanol/aislamiento & purificación , Micromonospora/fisiología , Antiinfecciosos/uso terapéutico , Antineoplásicos/uso terapéutico , Extractos Celulares , Chile , Clima Desértico , Descubrimiento de Drogas , Células Hep G2 , Humanos , Filogenia , Microbiología del Suelo , Streptomyces/fisiología , Estrés Fisiológico/genéticaRESUMEN
A novel actinobacterial strain, designated strain NEAU-JM2(T), was isolated from volcanic sediment collected from Longwan, Jilin province, north China and characterized using a polyphasic approach. The strain was found to have morphological and chemotaxonomic characteristics typical of the members of the genus Micromonospora. Phylogenetic analysis of the16S rRNA gene sequence also indicated that strain NEAU-JM2(T) should be classified in the genus Micromonospora and showed that close relatives are Micromonospora maoerensis NEAU-MES19(T) (99.5 %) and Micromonospora matsumotoense JCM 9104(T) (98.8 %). However, phylogenetic analysis based on the gyrB gene sequence showed that the isolate forms a separate subclade away from the close relatives in the neighbour-joining tree and also recovered with the maximum-likelihood algorithm. The low level of DNA-DNA relatedness allowed the isolate to be differentiated from M. maoerensis NEAU-MES19(T) and M. matsumotoense JCM 9104(T). Furthermore, strain NEAU-JM2(T) could also be distinguished from its close phylogenetic relatives by cultural and physiological characteristics. Therefore, it is proposed that strain NEAU-JM2(T) represents a novel species of the genus Micromonospora, for which the name Micromonospora vulcania sp. nov. is proposed. The type strain is NEAU-JM2(T) (=CGMCC 4.7144(T) = DSM 46711(T)).
Asunto(s)
Sedimentos Geológicos/microbiología , Micromonospora/clasificación , Micromonospora/aislamiento & purificación , Técnicas de Tipificación Bacteriana , China , Análisis por Conglomerados , Girasa de ADN/genética , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Micromonospora/genética , Micromonospora/fisiología , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Erupciones VolcánicasRESUMEN
A novel actinomycete, designated strain GUI 15(T), isolated from the root nodules of a Pisum sativum plant was characterized taxonomically by using a polyphasic approach. The 16S rRNA gene sequence of strain GUI 15(T) showed highest similarity to Micromonospora pattaloongensis TJ2-2(T) (98.7 %) and Polymorphospora rubra TT 97-42(T) (98.5 %). Phylogenetic analysis based on the gyrase B gene also supported the close relationship of these three strains, but indicated that strain GUI 15(T) should be assigned to the genus Micromonospora. Chemotaxonomic results confirmed the position of the isolate in the genus Micromonospora, but revealed differences at the species level. The novel strain could be distinguished from recognized Micromonospora species by using a combination of physiological and biochemical tests. Based on these observations, strain GUI 15(T) is considered to represent a novel species of the genus Micromonospora, for which the name Micromonospora pisi sp. nov. is proposed. The type strain is GUI 15(T) (=DSM 45175(T)=LMG 24546(T)).
Asunto(s)
Micromonospora/clasificación , Pisum sativum/microbiología , Nódulos de las Raíces de las Plantas/microbiología , Proteínas Bacterianas/genética , Secuencia de Bases , Girasa de ADN/genética , Micromonospora/genética , Micromonospora/fisiología , Datos de Secuencia Molecular , Filogenia , ARN Bacteriano/genética , ARN Ribosómico 16S/genética , Análisis de Secuencia de ARN , EspañaRESUMEN
Determination of cell growth was carried out by a polarographic system. The system was constructed of two platinum electrodes, a saturated calomel electrode, and a thermistor electrode. Responses of the system to the dissolved oxygen, pH, and temperature were examined. Cell growth of S. cerevisiae and M. olivoasterospora was monitored continuously by this system. In addition, this polarographic system could be applied to the measurements of cell populations of the human cancer cell L-1210 and mouse leukocytes. The measureable range for these animal cells was approximately 10(3)--10(5) cells/ml.