Zeitschrift fur allgemeine Mikrobiologie最新文献

Botryodiplodia theobromae and Aspergillus aculeatus were inoculated in carboxymethylcellulose (CMC) medium and on filter papers. Hydrolysis of the CMC medium and degradation of the filter papers were observed, indicating the production of C1 and Cx cellulases by the two rot pathogens. The C1 and Cx enzymes were also detected in filtrates of rotted orange fruits obtained by infection with the two pathogens. The cellulases could not induce rot development on their own. However, when they were added to pectinases in an enzyme inoculum, the incubation period for inducing rot development was shorter, thus establishing a secondary role for the cellulases in the rot development. Optimum conditions for the action of the cellulases included a neutral pH and temperature ranging from 25 to 30 degrees C.

Manganese oxidation by cell suspensions and cell extracts of a freshwater bacterium, designated strain FMn 1, was investigated. Manganese appeared to be oxidized in the periplasmic space. A conventional, membrane-bound-electron transport system was not utilized. An enzyme or enzyme complex and a cofactor, each of different molecular size, were located in different parts of the cell envelope. Results suggest that the cofactor reacts with manganese in the periplasmic space and that in the presence of oxygen it is reoxidized by the enzyme. The enzyme is probably loosely bound to the membrane. A combination of enzyme and cofactor in a crude preparation exhibited a pH optimum at around 7.0. The enzyme exhibited a temperature optimum at around 30 degrees C. No temperature optimum was found for the cofactor. The enzyme was heat-stable and could oxidize manganese under anaerobic conditions. The enzyme system appears to be different from others so far described.

Phenotypically different submerged mycelium conserves had been produced from a spore conserve of the HP-strain Streptomyces griseus and proofed in a product formation culture as a test system. The phenotypical characters induced on the base of the genotype proved in a cultivation cycle during 30-34 reduplications of the biomass constant. Employing the HP phenotype we investigated the possibility of economizing the substrate turnover by utilizing the anabolic potential for the synthesis of secondary substances and/or reducing the conservation catabolism during the stationary growth stage. As criteria for that served the stoichiometric turnover equation of the streptomycin biosynthesis and the quotient qO2/qGluc taking at full substrate oxidation the numerical value 6. During the stationary growth stage the relation of maintenance anabolism to maintenance catabolism in addition to the formation as secondary substances is not fixed in the tested HP phenotypes, but in a striking manner variable. The relation of by-product synthesis to secondary metabolism synthesis, too, is variable in the stationary growth stage with constant maintenance catabolism. Due to those response reactions on phenotypical manipulations an economization of the substrate turnover during the product formation stage with stationary growth is not possible in the streptomycin producer Streptomyces griseus.

The present study emphasizes the effects of different qualities of visible light, intensities of white light, temperature and pH on the sporulation in the green alga Pithophora oedogonia (Mont.) Wittrock. Of the different qualities of light used, green light was found to delay the initiation of sporulation. Percentage of sporulation was greatly decreased in yellow light followed by red light. Delay in time taken for initiation of sporulation and decrease in percentage sporulation were observed at 0.25 and 0.5 K lux intensity of white light. Sporulation upto the extent of its natural population was achieved with white light between 2 to 3.5 K lux, temperature between 20 to 30 degrees C and pH between 4-9.

Tmax, the maximum temperature for growth of Saccharomyces cerevisiae, decreased linearly with increasing concentrations of cycloheximide added to the medium, to about 20 degrees C at 2.5 microgram ml-1. In this concentration range thermal death was not enhanced. The Arrhenius plot of growth was shifted to lower temperatures as a function of the cycloheximide concentration and became dissociated from the Arrhenius plot of thermal death. It was concluded that the target site of cycloheximide, the cytoplasmic ribosome, is not identical with the physiological Tmax site of S. cerevisiae and that the binding of cycloheximide to its target sites is strongly enhanced by the temperature.

Added C1-compounds of the intermediates methanol, formaldehyde, formate and carbon dioxide show a catalytic effect on the growth rate and cell yield of CH4-assimilating bacteria GB 25 with serine pathway. Maximum stimulation is obtained by added amounts of about 20 mg C1-compound/g bacteria dry matter. The influence of C1-compounds decreases as follows: methanol greater than carbon dioxide greater than formate greater than formaldehyde.

An increase in the amount of membrane-bound DNA was found in B. subtilis cells with UV-induced DNA repair synthesis as compared to untreated cells. It was shown that DNA repair synthesis occurred in DNA membrane complexes (DMC) formed during UV-irradiation. UV-induced formation of DMC was observed in cells of wild type strains which were capable of repairing damaged DNA but not in a mutant defective in DNA-polymerase I. It was demonstrated that DNA-polymerase I is located on the membrane of B. subtilis cells. This suggested a participation of DNA-polymerase I in binding of the chromosome to the membrane in UV-irradiated cells. UV-induced DMC did not dissociate when the cells were treated with inhibitors of DNA-gyrase. It, therefore, was qualitatively different from the DMC found during replication. The mechanisms of binding of the damaged DNA to the membrane in UV-irradiated cells of B. subtilis are discussed.

The general control of amino acid biosynthesis was investigated in Candida spec. EH 15/D, using single and double mutant auxotrophic strains and prototrophic revertants starved for their required amino acids. These experiments show that starvation for lysine, histidine, arginine, leucine, threonine, proline, serine, methionine, homoserine, asparagine, glutamic acid or aspartic acid can result in derepression of enzymes. A correlation was found between the degree of derepression, growth of strains, and concentration of required amino acids. The amino acids pool pattern of mutants and revertants is different from that in the wild type strain.

Sodium fluoride induces filamentous growth of Erwinia carotovora when it is grown in liquid media containing aspartic acid only as the sole source of nitrogen. It is proposed that a stable complex of F(-)-Mg2+-enzyme and PO2(4) resulting in Mg2+ deficiency and consequent inability of E. carotovora cells to oxidize aspartic acid normally, is responsible for the formation of filaments in the presence of fluoride ions.