RESUMEN
The diversity and viability of prokaryotic communities in the primitive organomineral soils of East Antarctica have been studied; it has been shown that the total number of bacteria is smaller than and the viability of bacteria is similar to that in soils of the temperate zone. The prokaryotic communities are characterized by the occurrence of a major part of cells in filterable forms, which is higher than the analogous parameter for the temperate soils. The method of fluorescence in situ hybridization (FISH) revealed that the distribution of the main taxons is similar to that in the temperate soils: the portion of the domain Archaea is smaller than that of the domain Bacteria; the total content of Gram-negative bacteria (the phyla Proteobacteria, Acidobacteria, and Planctomycetes) is higher than that of Gram-positive bacteria (Actinobacteria). Within the phylum Proteobacteria, a significant variation of three proteobacterial classes has been noted along the profiles of the soils studied.
Asunto(s)
Células Procariotas , Microbiología del Suelo , Actinobacteria/genética , Regiones Antárticas , Archaea/genética , Bacterias/genética , Biodiversidad , Ecosistema , Bacterias Grampositivas/genética , Hibridación Fluorescente in Situ , Proteobacteria/genéticaRESUMEN
The number, potential viability, and taxonomic diversity (at the level of phylum) of the filterable forms of prokaryotes (FFP) are estimated in the main genetic horizons of high-moor peat. It was shown that the number of FFP reached 500 million cells in 1 g, i.e., up to 5% of the general size bacteria. The portion of viable cells among FFP (93-98%) was higher than that for the general size bacteria (60-68%). FISH-analysis (fluorescence in situ hybridization) showed that FFP contained the same phylogenetic groups as the population of general size bacteria (domain Archea and phylum Actinobacteria, Cytophaga, and Proteobacteria of the domain Bacteria).
Asunto(s)
Bacterias/genética , Microbiología del Suelo , Suelo , Sphagnopsida/microbiología , Bacterias/clasificación , Variación Genética , Hibridación Fluorescente in Situ , Filogenia , Células Procariotas/clasificación , ARN Ribosómico 16S/genéticaRESUMEN
The characteristics of microbial communities of the anthills of Lasius niger compared to the soil beyond the area of the strong effect of ants is given.
Asunto(s)
Hormigas , Ecosistema , Microbiología del Suelo , Suelo/análisis , Streptomyces/metabolismo , Animales , Flavobacterium/metabolismo , Bacterias Grampositivas/metabolismoRESUMEN
By means of dye L7012, the number and physiological condition (damage rate of membranes) of bacterial cells is defined. The results testify to considerable physiological heterogeneity of bacteria cells in soils. In fresh samples of soil, the percentage of intact cells reached 60-70%. Damaged membranes occurred in 30-40% of cells. The number of damaged cells dramatically increased downwards through the soil profile. Drying and freezing of soil samples considerably reduced the quantity of intact cells and increased the percentage of cells with damaged membranes; the number of intact cells was 10-20%. Treatment with biocide agents resulted in lysis of the majority of cells and cells injuries. However, some of the cells kept an intact cellular membrane, which testifies to the high stability of bacteria in soil. These data allow us to offer a method of staining a soil suspension with the use of luminescent dye L7012 with the quality of an express method that gives the chance to monitor the number and physiological condition of the bacterial complex of soils.
Asunto(s)
Bacterias/metabolismo , Mediciones Luminiscentes/métodos , Viabilidad Microbiana , Microbiología del SueloRESUMEN
The actinomycetes complexes in the rhizosphere of three agricultural plants by using the methods of luminescense microscopy and cup sowing were investigated. It was established, that concentration of prokaryotic biomass and biomass of actinomycetes mycelium in rhizosphere of plants is higher than in free from the radicals to soil. Rhizosphera of the oat (Avena sativa L.) and red clover (Trifolium pratense L.) is colonized by Streptomyces, Micromonospora and olygospore species. Dominante actinomycetes of winter rye (Secale cereale L.) are classified into the genera Micromonospora. It was shown that numbers and biomass of actinomycetes mycelium were fond to decreased, diversity of actinomycetes in contrast is increased in the series: "winter rye--oat--red clover". In connection with ecological safety the capability of increase with prokaryotes naturally disease suppressive soil and stability of plants to pathogen is discussed.
Asunto(s)
Actinobacteria/fisiología , Avena/microbiología , Secale/microbiología , Microbiología del Suelo , Trifolium/microbiología , Avena/fisiología , Raíces de Plantas/microbiología , Raíces de Plantas/fisiología , Secale/fisiología , Especificidad de la Especie , Trifolium/fisiologíaRESUMEN
Investigations showed that bacteria present in soil are resistant to one-day exposure to a saturated solution of ammonium nitrate and can well develop when transferred to laboratory nutrient media. The evaluated number of bacteria in NH4NO3-treated soil samples was nearly the same as in native soil samples, while was 1.5-2.5 times smaller in the former than in the latter case when microbial succession in the soil samples was initiated by wetting them. Bacteria (particularly gram-negative ones) occurring at the early stages of succession were the most sensitive to salt stress. Bacteria in soil were found to be much more resistant to salt stress than the same bacteria isolated in pure cultures.