Folia Microbiologica

Hoštacká, A.; Majtán, V.

doi: 10.1007/BF02898607pmid: 8112696

Aminoglycoside antibiotics, most effective at the level of 1/4 of the MIC, suppressed all the tested activities ofP. aeruginosa, except cytotoxicity. Proteinase activity was decreased to 60% (gentamicin) and 63% (streptomycin), permeability was reduced to 61% (gentamicin) and 73% (streptomycin), phospholipase C to 13% (gentamicin) and 51% (streptomycin) of the control values. Subinhibitory concentrations ofβ-lactams inhibited only phospholipase C activity to 89% (ticarcillin) and 64% (cefotaxim) of the control values. These antibiotics did not suppress the cytotoxic activity and increased protease activity up to 155% (ticarcillin) and 192% (cefotaxim) as well as permeability up to 121% (ticarcillin) and 154% (cefotaxim) of the control values.

Gupta, R.; Aparna, ; Shanker, B.; Saxena, R.; Kuhad, R.

doi: 10.1007/BF02898592pmid: N/A

Bacillus licheniformis solubilized a range of inorganic phosphates and five different Indian rock phosphates (low grade) to varying extent in broth culture and in soil. Statistical evaluation indicated that broth cultures alone were inadequate indicators of the potential for microbial solubilization of rock phosphates.

Nečásek, J.; Němcová, M.; Lisá, L.; Dusbábková, J.; Našinec, V.; Požárková, D.

doi: 10.1007/BF02898601pmid: N/A

Cell suspension ofRhizobium leguminosarum bv.viciae D-253,R. leguminosarum bv.viciae D-560 andR. meliloti D-557 were incorporated into sterile diatomaceous earth (DE) and dried at room temperature. Initial numbers of colony-forming units (CFU), expressed as log10, were 8.27, 8.36 and 8.51, respectively. After 5 months of storage the CFU numbers were 0.00, 5.99 and 7.43, respectively.R. meliloti D-557 showed only minor lowering of the CFU number even after 16 months of storage (log10=7.07). After 7 months of storage in DE some single-colony isolates of D-253 produced 10–100 times higher CFU numbers than the original strain. The isolates of D-560 were much more drought-tolerant. The cells of the original strain died after 7 months of storage, log10 of CFU was 6–7 in the isolates. In both strains some of their drought-tolerant isolates had the same specific acetylene-reducing activity of nodule tissue as the original strains. Diatomaceous earth seems to be a prospective carrier for the formulation of bacterization preparations.

Holubová, I.; Brenner, V.; Hubáček, J.

doi: 10.1007/BF02898593pmid: 8112692

To develop a host-vector system forMethylobacterium sp. using a construct based on a small indigenous methylotrophic plasmid, theE. coli —Methylobacterium sp. shuttle vector pWUBR (12.7 kb, Apr, Tcr) was constructed by joining theE. coli plasmid pBR328 and the cryptic plasmid pWU7 (7.8 kb), isolated from the soil facultative methylotrophic bacterium,Methylobacterium sp. strain M17.Via mobilization by the pDPT51 R plasmid, belonging to the IncP-1 incompatibility group, plasmid pWUBR was transferred into the original host of cryptic plasmid pWU7, strain M17, where a competition between the introduced hybrid plasmid and the indigenous cryptic plasmid took place, and into the plasmidlessMethylobacterium sp. strain R2b. The stability of pWUBR in Tcr methylotrophic transconjugants after 25 generations of growth under nonselective conditions was more than 90 % in both hosts. The ability to replicate in R2b strain demonstrates that the host spectrum of pWUBR is not restricted to the original host of pWU7 and indicates the possibility to use the present system for other methylotrophs.

Schwippel, J.; Votruba, J.

doi: 10.1007/BF02898600pmid: N/A

A numerical method suitable for computer simulation of complex continuous cultivation of microorganisms is described in detail. The method makes possible an iterative solution of a set of nonlinear algebraic equations that represent the steady state mass balances of a chemostat. The continuation algorithm makes it possible to map the dependence of state variables for the whole range of dilution rates. Easy implementation of the method is possible when the computer code written in BASIC language is used. Two examples, first for oxygen limited cultivation, second for anacrobic acetone — ethanol — butanol fermentation, demonstrate the feasibility of the method.

Halder, A.; Chakrabartty, P.

doi: 10.1007/BF02898602pmid: N/A

A large number of strains ofRhizobium were able to solubilize the insoluble phosphate compound, hydroxy-apatite, in liquid culture. Solubilization of hydroxyapatite byRhizobium was not mediated by an enzyme but acidity developed in the cultures was involved in the process. An inverse relationship between the level of soluble phosphate and medium pH was evident. The ability to solubilize hydroxyapatite varied among the strains. In a medium without NH 4 + , some of the strains showed better activity than when NH 4 + was present, suggesting involvement of different mechanisms for phosphate solubilization.R. meliloti SU 47 produced 2-ketogluconic acid along with an unidentified acid in the medium containing NH 4 + . 2-Ketogluconic acid was identified as the major factor in inorganic phosphate solubilization. Initial presence of soluble phosphate in the medium had no discernible influence on the extent of hydroxyapatite solubilization. Initial presence of calcium reduced solubilization of phosphate and addition of EDTA to stationary phase cultures caused an increase in the level of soluble phosphate.

Olasupo, N.; Scott-Emuakpor, M.; Ogunshola, R.

doi: 10.1007/BF02898595pmid: 8112693

The heavy metal resistance of yeasts isolated from sugary substrates such as orange, palm wine and pineapple and identified asSaccharomyces carlsbergensis andS. cerevisiae was studied. The yeast isolates were tested against different concentrations of cadmium, copper, manganese, silver and zinc salts ranging from 1 to 20 mmol/L. Local yeasts showed resistance to 3–15 mmol/L cadmium, 18–20 copper, 16–20 manganese, 1–9 silver and 16–19 for zinc. The significance of the results is discussed in relation to the effects of heavy metals on growth of microorganisms and selection of yeasts for the brewing industry in Nigeria.

Volfová, O.; Žižka, Z.; Anděrová, M.

doi: 10.1007/BF02898596pmid: N/A

All deviations from optimum cultivation temperature affect strongly the physiology and morphology of cells ofCandida boidinii strain 2 during growth in methanol-limited chemostat. The optimum cultivation temperature was 28–30 °C at which maximum cell concentration and maximum cell yield (Y S 0.4 g/g) were achieved. At suboptimal growth temperatures the cells were rich in cell protein, RNA, alcohol oxidase (AO) and in peroxisomes. Formation of cubic peroxisomes and a 20 % decrease of budding cells in the population was observed. At supraoptimal growth temperatures (>30 °C) a sharp decrease in AO activity was accompanied by degradation of peroxisomes in the cells. The culture forms pseudomycelium: at 34 °C the cells stop growing and they are washed out of the bioreactor.

Čerňáková, M.

doi: 10.1007/BF02898603pmid: N/A

The effect of the insecticide Nerametrine EK-15 (containing an active supercypermetrine component) on nitrification, nitrogen fixation, CO2 production and cellulase activity of soil microorganisms was investigated. Four soil types were sampled from various localities. Supercypermetrine at 31 pmol/kg soil affected remarkably the metabolic activity of all soil samples tested by producing CO2 after a 1-d exposure. After a 14-d exposure no difference in the metabolic activity related to CO2 production was noticed in the case of garden soil where the insecticide at 31 pmol/kg soil and the unaffected control were used. As far as other samples are concerned, the supercypermetrine concentration amounting to 31 pmol/kg soil explicitly inhibited the metabolic activity of soil microorganisms. On the other hand, concentrations of 0.61 and 6.1 pmol/kg soil stimulated the metabolic activity of soil in the locality of Senica. The soil samples enriched with nutrients (organic nitrogen in urea) manifested an evident inhibition at 31 pmol/kg soil. The nitrification activity of all soil types was interrupted at 61 pmol/kg soil. Supercypermetrine 0.12 pmol/L stopped completely nitrogen fixation withA. chroococcum and that corresponding to 0.3 pmol/L stopped aerobic cellulase decomposition.

Douka, C.; Xenoulis, A.; Paradellis, T.

doi: 10.1007/BF02898599pmid: N/A

The salinity tolerance of aRhizobium meliloti strain, used as inoculum, was established by growing the strain for seven consecutive generations in a broth containing 0–1.2% NaCl. Identical generation times and viable cell numbers were observed. Furthermore, the nodulation, plant yield and elemental composition ofM. sativa grown on agar slopes responded identically to all inocula, irrespective of the levels of NaCl with which they were grown. The effect of salinity on the ability ofM. sativa to grow and fix nitrogen was tested on agar slopes containing 0–1.2 % NaCl. At 0.0, 0.2 and 0.4 % NaCl the induced fixation was identical as indicated by the constant values of nodulation and plant yield. However, a significant reduction at 0.8 and almost a total suppression at 1.2 % NaCl occurred. Commensurate was the effect of inoculation on the elemental composition ofM. sativa as a function of salinity at the agar medium. The concentration of Mo, Mn, Sr, Cu and Zn, is clearly affected by fixation while salinity has no effect. Their concentration in the inoculated plants is significantly lower compared to the uninoculated at 0–0.4 % NaCl levels, when significant fixation occurred. In contrast, at 0.8 and 1.2 % NaCl their concentration in inoculated and uninoculated plants tends to overlap. On the other hand, the concentration of K, Rb, Br and Cl is affected mainly by salinity. Finally, Ni is affected by neither salinity nor nitrogen fixation.