Comparison of expression of key sporulation, solventogenic and acetogenic genes in C. beijerinckii NRRL B-598 and its mutant strain overexpressing spo0A.

The production of acetone, butanol and ethanol by fermentation of renewable biomass has potential to become a valuable industrial process. Mechanisms of solvent production and sporulation involve some common regulators in some ABE-producing clostridia, although details of the links between the pathways are not clear. In this study, we compare a wild-type (WT) Clostridium beijerinckii NRRL B-598 with its mutant strain OESpo0A, in which the gene encoding Spo0A, an important regulator of both sporulation and solventogenesis, is overexpressed in terms of solvent and acid production. We also compare morphologies during growth on two different media: TYA broth, where the WT culture sporulates, and RCM, where the WT culture does not. In addition, RT-qPCR-based analysis of expression profiles of spo0A, spoIIE, sigG, spoVD, ald and buk1 genes involved in sporulation or solvent production in these strains, were compared. The OESpo0A mutant did not produce spores and butanol titre was lower compared to the WT, but increased amounts of butyric acid and ethanol were produced. The gene spo0A had high levels of expression in the WT under non-sporulating culture conditions while other selected genes for sporulation factors were downregulated significantly. Similar observations were obtained for OESpo0A where spo0A overexpression and downregulation of other sporulation genes were demonstrated. Higher expression of spo0A led to higher expression of buk1 and ald, which could confirm the role of spo0A in activation of the solventogenic pathway, although solvent production was not affected significantly in the WT and was weakened in the OESpo0A mutant.

[Basophil histamine and peripheral blood serotonin in metal and toxic gas poisoning]. / Histamina bazofilów i serotonina krwi obwodowej w zatruciach metalami i gazami toksycznymi.

Thirty-six persons in non-occupational exposure to air polluted by sulphur and nitrogen oxides and metallic lead and cadmium dust have been examined. The levels of basophil histamine and whole blood serotonin have been determined. A decrease in the basophil histamine level observed in our studies may be indicative of allergic effects of industrial pollution in that region. Simultaneously, we observed changes in the ratios of biogenic amines responsible for immunological response, i.e. changes in the histamine-serotonin ratio.