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Key Words inorganic polyphosphates, functions, transport, enzymes, metabolism * Abstract In microbial cells, inorganic polyphosphate (polyP) plays a significant role in increasing cell resistance to unfavorable environmental conditions and in [...]

Comparison of the levels of the protein carbonyl groups in response to peroxide stress revealed enhanced stress resistance in Purpureocillium lilacinum strains isolated from soils with high content of copper or radionuclides compared to the strains isolated from uncontaminated soils. While in background strains resistance to peroxide stress increased with glucose content in the medium increasing from 0.002 to 2%, the strains from radionuclides- or copper-contaminated soils did not exhibit this pattern. Respiratory activity and polyphosphate content were compared for radiation-resistant strain 1941 and strain SM from the area with background radioactivity. For the protoplasts of strain 1941 isolated from the Chernobyl zone, elevated respiratory activity was revealed on the media with low glucose content. Under the control conditions, the content of inorganic polyphosphates (polyP) in strains 1941 and SM was the same. Under conditions of peroxide stress, only the background strain SM grown on the medium with low glucose concentration exhibited decreased levels of inorganic polyphosphates. Independent of glucose concentration in the medium, in both P. lilacinum strains polyP content increased in the course of regeneration after peroxide stress. [ABSTRACT FROM AUTHOR]

Cellobiose lipid B, a natural fungicide produced by the yeast Pseudozyma fusiformata, induces the leakage of K+ and ATP from cells of Saccharomyces cerevisiae. The presence of glucose decreases the effective concentration of cellobiose lipid B. The concentration of cellobiose lipid B was selected that results in a high rate of K+ leakage and a five-to sevenfold decrease in the intracellular ATP content, while the accumulation of acid-soluble polyphosphates decreased only by half. These results indicate the possibility of synthesis of these polymers which is independent of the ATP level and of the ion gradient on plasma membranes. [ABSTRACT FROM AUTHOR]

Cells of the methylotrophic yeast Ogataea parapolymorpha have two genes encoding low-affinity phosphate transporters: PHO87, encoding the plasma membrane transporter, and PHO91, encoding a protein, which is homologous to the Saccharomyces cerevisiae vacuolar membrane transporter. Earlier, we reported that inactivation of PHO91 in O. parapolymorpha interferes with methanol utilization due to the lack of activity of methanol oxidase encoded by the MOX gene. In this work, we showed that this defect was completely suppressed by inactivating the PHO87 gene or introducing additional copies of the MOX gene into the cell. The PHO91 gene knockout decreased the level of long-chained polyphosphates only in methanol-grown cells, but not in glucose-grown cells. This effect remained even in the strain with extra copies of MOX, which rescues the ability of the mutant to grow on methanol. In contrast, the PHO87 gene knockout changed the levels of short-chained and long-chained polyphosphates in both methanol- and glucose-grown cells. Inactivation of PHO91 did not change vanadate resistance, while inactivation of PHO87 increased this resistance. Our data suggest that in O. parapolymorpha, Pho87 and Pho91 transporters have different roles in inorganic polyphosphate metabolism and adaptation to methanol consumption., Competing Interests: Declarations. Ethical approval: No ethical approval was required. Conflict of interest: The authors declare no competing interests., (© 2024. Institute of Microbiology, Academy of Sciences of the Czech Republic, v.v.i.)