Influence of growth rate and starvation on fluorescent in situ hybridization of Rhodopseudomonas palustris

Abstract

In situ hybridization with a fluorescently labeled 16S rRNA-targeted probe was examined using Rhodopseudomonas palustris as a model organism, which had been grown at different rates and under different conditions of growth and starvation. The specific growth rate did not affect the percentage of hybridized cells in aerobically grown R. palustris cultures. However, significant changes in the percentage of hybridized cells occurred during extended periods of starvation. These changes were observed both in batch cultures grown and starved aerobically in the dark, and in cultures grown phototrophically and starved anaerobically in the dark. Aerobic growth in batch culture and subsequent starvation resulted in a complete lack of detectable hybridization after 20 days of starvation. In contrast, even after 30 days of starvation, 50% of all cells were still detectable in cultures grown aerobically at growth rates <0.06 h(-1) and then starved aerobically in the dark. The same was true for phototrophically grown cells that were starved anaerobically in the light. During starvation there was a clear, though non-linear, positive correlation between the percentage of hybridized cells and the RNA content. In contrast, no direct correlation was observed between the number of hybridized cells in a culture and the viability of this culture. Thus, in habitats with growing, non-growing, and starving bacteria, data on quantitative detection of populations based on 16S rRNA-targeted probing should be used with extreme caution as the detectability of the individual cells is strongly influenced by their physiological history and current physiological state.

Isolation of methane oxidising bacteria from soil by use of a soil substrate membrane system

“…Even though colonies were only seen on the membranes when methane was present during the incubations and when samples with significant methanotroph activity were filtered onto the membranes, attempts to identify methanotroph colonies directly on the membranes failed. Whole cell fluorescent hybridisation did not result in a probe specific signal from cells in the large colonies, probably due to low ribosome content as a result of a starvation response [51].…”

Differences in Survivability under Starvation Conditions Among Four Species of Purple Nonsulfur Phototrophic Bacteria

“…They have been shown to markedly contribute to carbon, nitrogen, and sulfur cycles on the Earth (10). Previous studies examined the survivability of purple phototrophic bacteria under starvation conditions (2, 11). Breznak et al (2) reported that the carbon-starved cells of Rhodospirillum rubrum strain Ha remained viable for longer in the light than in the dark.…”

“…Breznak et al (2) reported that the carbon-starved cells of Rhodospirillum rubrum strain Ha remained viable for longer in the light than in the dark. Oda et al (11) demonstrated the positive effects of illumination on the survivability of Rhodopseudomonas palustris strain DCP3. The positive effects of light on starvation survival have also been reported in some strains of aerobic bacteriochlorophyll-containing bacteria (4, 7, 13, 14).…”

Strong, weak, and missing links in a microbial community of the N.W. Mediterranean Sea

“…In single cells, FISH probe signal intensity is directly related to cellular rRNA content [59]. The fraction of cells detectable using the eubacteria probe (archaebacteria were barely detectable) should then equal the fraction of cells that each contain a minimum number of ribosomes equal to about 5 fg of RNA [42]. For a bacterial cell, ribosome number can reflect nutritional condition as well as nutritional history.…”