Starvation survival of Gordonia polyisoprenivorans CCT 7137, isolated from contaminated groundwater in Brazil

Abstract

Gordonia polyisoprenivorans CCT7137, exopolysaccharide-producing bacterium, was isolated from groundwater contaminated with leachate in a former municipal landfill site (São Paulo, Brazil). The strain was submitted to starvation in phosphate-buffered saline solution for 56 days so as to evaluate its behavior regarding cuturability and cell morphology. As a response to starvation, G. polyisoprenivorans CCT7137 presented reduction in viable cell count, cell size and cell shape alteration. The initial number of viable cells was 1.51 · 10 7 c.f.u. ml. After 7 days of starvation culturability dropped to 13.70% (2.07 · 10 6 c.f.u/ml) and, after 56 days, to 3.25% (4.93 · 10 5 c.f.u/ml). It was also observed that after 7 days of starvation the cell size presented an average reduction in the values of length, length/width ratio, volume and area of 50, 58, 40 and 42%, respectively. The length/width ratio showed a change of shape from rod to coccobacillus. Changes in cell dimensions and distribution of cell into classes were not significant after day 7 of starvation. The results obtained show that it is not necessary for the strain to starve for more than a week to obtain G. polyisoprenivorans CCT7137 size-reduced cells. The results also indicate the potential for its starved forms to be used in future tests in porous medium to study the production of exopolysaccharide in situ.

Effects of Aromatic Compounds Degradation on Bacterial Cell Morphology

“…Gordonia sp. strain 12/5 cultured in VD completed with glucose (Figures 5A and 6a) had a cell morphology similar to that described in other electron microscopy studies [51,53,54].…”

“…This has been observed in strains belonging to the two genera represented in the present study as well. Species of Gordonia and Rhodococcus gained reduced cell size during the stationary phase [51,54,58,59]. In the present study, rod shape shortening to coccoid forms was observed in Rhodococcus strains, 1G/1 cultured on p-cresol and 14/1 cultured on o-cresol (Figures 7C and 9C).…”

“…Thus, starvation is generally considered to cause the occurrence of dwarf cells [22]. Some specific kinds of nutrition limitations, like nitrogen, phosphate, or water limitations, can result in an inhibition of cytokinesis with the occurrence of giant filamentous cells [21,54]. During bacterial growth, the stationary phase is characterized by cellular changes in response to starvation.…”