Folia Microbiologica

Schiel, R.; Kunstýř, I.; Uhr, G.; Kaup, F. -J.

doi: 10.1007/bf02814371pmid: 7690004

A new giant Gram-negative non-cultivatable symbiotic endospore-forming bacterium was found in the gut of the European hamster. This “Metabacterium” sp., provisionally named “Metabacterium criceti”, sp. n., has a length of approximately 20 μm and thickness of 4 μm. It forms 1 to 2 cylindrical endospores, approximately 9 μm long and 1.4 μm thick. TEM-micrographs show a cell wall structure characteristic of Gram-negative bacteria. Vegetative cells are filled with granules 0.3 μm in diameter which resemble starch granules. The reproduction occurs with binary fission and by formation of two endospores. Of thirteen biochemical components sought, four,i.e. glycogen, triacylglyceroles, peroxidase and alkaline phosphatase, were not found. Starch, acid mucosubstances, DNA, RNA, lipids, proteins, adenosine triphosphatase and acid phosphatase were found in different patterns, depending on the developmental stage of the bacterium. In the vegetative cell stage all these components, with the exception of starch, were found. In the endospore-bearing cell stage, only the starch-like cell component granulose could be detected. In free endospores only DNA, RNA and acid phosphatase were found. Some of the components,i.e. DNA, lipids, starch-like granulose, were linked to certain cell substructures, the distribution of others,viz. polysaccharides, RNA, adenosine triphosphatase and proteins was diffuse. The lipids, found only in vegetative cells, were associated with the cell wall.

Stünkel, S.; Alves, J.; Kunstýř, I.

doi: 10.1007/bf02814372pmid: 8365693

The vegetative cell of “Metabacterium polyspora” is “cucumber-shaped”, about 21×5.7 μm, Gram-negative. Cylindrical endospores are best stained by Rakette and Ziehl-Neelsen staining. The bacterium reproduces by sporulation (2 to 8 endospores per cell) and by binary fission. Lateral, bow-like “hatching” of the endospores was seen. About 52% of guinea pigs harbor 5×106, 36% below 2×106 and 1% more than 1×108 “M. polyspora” in 1 g of caecal content. Dipicolinic acid was demonstrated using HPLC in the caecum homogenate from a guinea pig. The amount of it was proportional to the number of spores. Cultivation under strict anaerobic conditions did not succeed. It was possible to cultivate this giant endosymbiontin vitro in a heteroxenic culture incubated in a 5% CO2 atmosphere using liquid medium supplemented with cell-free filtrate of the caecum. The caecum filtrate containing undefined growth factor(s) is necessary for long-term culture. The replication rate was low. These findings suggest that the giant endosymbiont “M. polyspora” is a spore-forming prokaryote without the attributes of a strict anaerobe.

Ouf, S. A.; Sherif, S. M.

doi: 10.1007/bf02814374pmid: 8365695

A series of 12 pyrimidine derivatives were prepared and testedin vitro against growth, sporulation and nucleic acid content ofFusarium oxysporum f. sp.lycopersici andHelminthosporium oryzae. Introduction of a thiazole ring together with two aryl groups into 2-aminopyrimidine brought about drastic toxicity for both fungi. Pyrimidine derivatives with aryl groups alone were less toxic. Nitro groups were found to enhance the toxicity of the pyrimidine derivatives especially when substituted in the ortho-position of the aryl groups. Inhibition of nucleic acid synthesis of both fungi was attributed mainly to the presence of the thiazole ring.

Cigáneková, V.; Kallová, J.

doi: 10.1007/bf02814375pmid: 8365696

Antibacterial activity of alkyldimethylamine oxides and lodaminox was determinedin vitro in 11 strains of clostridia. The most efficient was (1-methyldodecyl)dimethylamine oxide (MIC=7.8–78 μmol/L). Iodaminox was about twice as efficient (MIC=3.9–31 μmol/L). The bactericidal activity of both compounds was tested at different periods of exposure, ambient pH and cultivation temperature on three species of clostridia. The activity of both compounds was the highest at pH 6 and 40°C.

Hölker, U.; Érsek, T.; Höfer, M.

doi: 10.1007/bf02814376pmid: N/A

Cell-free supernatant of pelleted zoospores was found to be more suitable for maintaining viable zoospores and developed cysts than the supernatant of mature cysts. Conductivity and pH measurements indicated quantitative changes in the ionic composition of a suspension ofP. infestans zoospores during their conversion into cysts. An increase in conductivity in the incipient cyst suspension was followed by a decrease of conductivity in the maturing cyst suspension. The conductivity changes correlated closely with K+ fluxes which, in turn, coincided with the reverse, but stoichiometrically smaller, H+ fluxes. Zoospores treated with 1.5 μmol/L DCCD (an inhibitor of plasma membrane H+-ATPase) or 100 mmol/L Li+ (an inhibitor of cell motility) released predominantly K+ and other cations and their O2 consumption decreased. The H+/K+ exchange is therefore very probably associated with an operation of the plasma membrane H+-ATPase. The differential decrease in respiration caused by DCCD and Li+ was used to estimate the energy demand for cell motility and spore development.

Nguyen Thi, B. N.; Turian, G.

doi: 10.1007/bf02814378pmid: N/A

In contrast to cytochalasin D which selectively prevents differentiation of female gametangia, cytochalasins A, B and E also masculinizeAllomyces arbuscula by preventing septation between female and male gametangia, thereby allowing the dominant expression of the male characteristics.

Ghosh, B.; Das, T. K.

doi: 10.1007/bf02814379pmid: N/A

Two respiration-deficient mutants (rd) were isolated from the acetate-nonutilizing mutants (acu) induced by N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) inAspergillus ochraceus. A complementation analysis of the tword mutants indicated that MNNG had caused a mutation at a single locus. The diameter of the tword mutant colonies in glucose medium was found to be small in comparison to that of the wild type and the otheracu mutants; the diameter of the isolated mutant colonies in acetate medium was very small. The grown zone ofrd mutants remained colorless up to 20 h incubation in 2,3,5-triphenyltetrazolium-overlaid solid Czapek-Dox medium and it turned pink after prolonged incubation, whereas the wild type and the otheracu mutants became pink within 30 min in the same medium. Therd mutants were further characterized by measuring the respiratory activities of intact mycelia in the presence of glucose.

Támová, G.; Betina, V.; Farkaš, V.

doi: 10.1007/bf02814380pmid: N/A

Conditions for an efficient high-yield procedure for the preparation of protoplasts fromTrichoderma viride have been determined. The optimum yield of protoplasts was obtained using 15–18-h-old unbranched mycelia, 0.7 mol/L KCl in phosphate buffer (pH 6), and 5 % (W/V) of lyophilized snail gut-juice enzyme. The conversion of mycelia to protoplasts was complete within 40–60 min incubation at 30 °C.

Kogan, G.; Šandula, J.; Šimkovicová, V.

doi: 10.1007/bf02814381pmid: 8365697

Structure of the glucomannan isolated from the cell walls ofCandida utilis has been investigated using acetolysis fragmentation, methylation analysis, and NMR spectroscopy. The structure of the glucomannan resembles that of the cellular mannans of otherCandida species, except that the longer tetra- and pentasaccharide side-chains are terminated with a glucosyl residue. Presence of the nonreducing glucosyl groups at the ends of the side-chains caused theC. utilis not to cross-react in a double immunodiffusion test with otherCandida species that possess mannan antigens and cross-react withHansenula species with glucomannan antigens.

Sýs, J.; Prell, A.; Havlík, I.

doi: 10.1007/bf02814384pmid: N/A

The distributed data acquisition and control system consisting of two process-oriented stations supervised by a master operator-oriented station was developed for fermentation experiment purposes. Ability of the system for study, analysis and control, as well as adequacy of the proposed methods and strategies for process investigation were proved. Some practical experiences with computer driven experiments on physiological state modulation ofC. utilis andB. megaterium in the laboratory fermentor are reported.