Relationship of prodigiosin condensing enzyme activity to the biosynthesis of prodigiosin and its precursors in Serratia marcescens

Prodigiosin condensing enzyme (PCE) activities were present in Serratia marcescens wild type 08, mutants OF, WF and 9-3-3. Their specific activities exhibited different maxima and at different times during the late log phase or the early stationary phase of cell growth. The levels of prodigiosin and its precursors also showed a significant increase at this period. The results support that prodigiosin and/or its precursors are secondary metabolites. The ubiquity of the PCE activity in mutants deficient in prodigiosin biosynthesis suggest that this particular enzyme may also be present in non-pigmented clinical isolates.     

Visualization of centromeric spots in the chromosomes by UV-light exposure

Summary When exposed to UV-light in the presence of Hoechst 33258, chromosomes ofAllium cepa were progressively photolyzed with increasing length of exposure; they retained their delineated contours, centromeric spots and sometimes secondary constriction bands.     

Nucleic acids and protein synthesis in mice tumor and normal cells after irradiation at 365 nm in the presence of psoralen

Riassunto L'irradiazione a 365 nm in presenza di psoralene, furocumarina fotosensibilizzatrice cutanea non sostituita, influisce in modo diverso sulla sintesi macromoleculare in alcune cellule tumorali e normali del topo.     

Inhibition of prodigiosin formation inSerratia marcescens by adenosine triphosphate

Summary ATP, inorganic phosphate and ribose inhibited prodigiosin formation inSerratia marcescens, but adenine did not. ATP was not hydrolyzed by the organism during the experiment.     

Inhibition of induction of group A bacteriocins ofSerratia marcescens by rifampin

Zusammenfassung Rifampin blockierte die Induktion von Gruppe A Bakteriozinen in bakteriozinogenenSerratia marcescens Zellen; demnach scheint die Induktion dieser Bakteriozine auf funktionstüchtiger, DNS-abhängiger RNS-Polymerase der Wirtszellen zu beruhen. Rifampin hatte keinen Einfluss auf die Empfindlichkeit von Indikatorzellen auf Gruppe A Bakteriozine; demzufolge scheint die bakterizide Wirkung dieser Bakteriozine unabhängig von Proteinsynthese durch Indikatorzellen zu sein.     

Conversion of psoralen DNA monoadducts in E. coli to interstrand DNA cross links by near UV light (320–360 nm): Inability of angelicin to form cross links,in vivo

Summary Both angelicin and psoralen monoadducts formed in vivo in E. coli by near UV light produce lethal and mutagenic effects. However psoralen monoadducts are converted to cross links by higher doses of UV; angelicin monoadducts are not. The relevance of these results to psoralen photosensitization is discussed.Supported by the National Research Council of Canada.     

Conversion of psoralen DNA monoadducts in E. coli to interstrand DNA cross links by near UV light (320-360 nm): inability of angelicin to form cross links, in vivo.

Both angelicin and psoralen monoadducts formed in vivo in E. coli by near UV light produce lethal and mutagenic effects. However psoralen monoadducts are converted to cross links by higher doses of UV; angelicin monoadducts are not. The relevance of these results to psoralen photosensitization is discussed.     

Dominant lethal mutations induced by14C in mice

Summary The mutagenic potential of 1.0 Ci¹⁴C was evaluated in Swiss albino male mice by the dominant lethal assay. A significant increase in post-implantation loss was seen, the maximum being in the 3rd week after treatment.Authors express their thanks to University Grants Commission, New Delhi, for financial assistance.     

Effect of feeding psoralen on the copper content of different organs in albino rats

Zusammenfassung Psoralenfütterung von Ratten bewirkt eine Vermehrung des Kupfergehaltes in der Milz und eine Verminderung in der Leber. In der Haut sind die Werte nicht einheitlich.     

Dose-effects of 8-methoxypsoralen and long wave UV-light in 3T3 cells: evaluation of phototoxic index.

3T3 cells were cultured until confluency and treated with various doses of 8-methoxypsoralen followed by long wave UV light irradiation. The inhibition of 3H-thymidine incorporation was dose-dependent for both, psoralen and light. A phototoxic index (PTI) was established demonstrating that a constant correlation between psoralen and UVA light exists for the photoinactivation in living cells.     

Dose-effects of 8-methoxypsoralen and long wave UV-light in 3T3 cells: evaluation of a phototoxic index

Summary 3T3 cells were cultured until confluency and treated with various doses of 8-methoxypsoralen followed by long wave UV light irradiation. The inhibition of³H-thymidine incorporation was dose-dependent for both, psoralen and light. A phototoxic index (PTI) was established demonstrating that a constant correlation between psoralen and UVA light exists for the photoinactivation in living cells.Supported by Deutsche Forschungsgemeinschaft.We thank Miss Anne Schröder for her skillful assistance.     

Suppression of PHA-induced lymphocyte blastogenesis by concomitant presence of PPD in the culture

Summary PHA-induced lymphocyte blastogenic response was remarkably suppressed by the simultaneous presence of PPD in cultures of lymphocytes derived from individuals sensitized to PPD, but not affected by the presence of PPD when the cultures contained lymphocytes from an individual not sensitized to the protein. This double stimulation blastogenesis study with PHA and a specific antigen is feasible as a simple and rapid test to measure cell-mediated immunity to the antigen.Supported by United States grant USPHS Grant AM 27384.