A cytological characterization of the parasitic action of ultramicrobacteria NF1 and NF3 of the genus Kaistia on chemoorganotrophic and phototrophic bacteria

Abstract

Two strains (NF1 and NF3) of free-living chemoorganotrophic bacteria have been isolated from multiyear oil slime and Pedilanthus tithymaloides rhizosphere and ascribed to the genus Kaistia of the class Alphaproteobacteria on the basis of the nucleotide sequences of 16S rRNA gene and phenotypic characteristics. These strains can be assigned to ultramicrobacteria as their populations are represented by two subpopulations: (1) ultrasmall cells, on average 200-300 nm in diameter and <0.1 microm(3) in volume, of up to 60% of the total number of cells in a population, and (2) cells 400-800 nm in diameter and 0.15-0.5 microm(3) in volume, of up to 40% of the total number of cells in a population. The interaction of the isolated ultramicrobacteria strains (IUMB) with different bacterial species has been studied in cocultures grown under starvation and in complete nutrient media. It has been found that IUMB can be facultative parasites on certain species of chemoorganotrophic and phototrophic bacteria. The interaction of IUMB with prey bacteria exhibits the extracellular type of parasitism and involves establishing stable cell-cell contacts between the parasites and their prey to cause destruction of host cells.

Characterization ofMelioribacter roseusgen. nov., sp. nov., a novel facultatively anaerobic thermophilic cellulolytic bacterium from the classIgnavibacteria, and a proposal of a novel bacterial phylumIgnavibacteriae

“…Cell morphology was examined under phase‐contrast light microscope (Olympus CX‐41). To prepare ultrathin sections (according to Duda et al ., ), the biomass of cells grown on Widdel modified medium with maltose in anaerobic conditions or CMC in aerobic conditions was used.…”

Characterisation of a stable laboratory co-culture of acidophilic nanoorganisms

“…9 even hypothesized that it might be a general characteristic of previously uncultivable bacterial phyla that the organisms belonging to these phyla are small 9 . Thus far, isolated ultramicrobacteria belong to different phyla including Actinobacteria 10 , Bacteroidetes 11 or Alphaproteobacteria 12, 13 . They have cell volumes between <0.1 µm³ and <0.004 µm³, and their energy metabolism is described as chemoorganotrophic, heterotrophic or facultatively parasitic.…”

Ruthenibacterium lactatiformans gen. nov., sp. nov., an anaerobic, lactate-producing member of the family Ruminococcaceae isolated from human faeces

“…Ultrathin sections (50-60 nm thick) of culture pellets were prepared as described by Duda et al (2009) and examined in a JEOL JEM-1200EX transmission electron microscope at an accelerating voltage of 80 kV.…”