Effect of aluminium and nickel on aflatoxin production byAspergillus flavusMalini, R.; Mukerji, K. G.; Venkitasubramanian, T. A.
doi: 10.1007/bf02872924pmid: 6427072
Effect of nickel and aluminium was studied on aflatoxin and lipid production by two strains ofAspergillus flavus in a sucrose—asparagine—salts medium. Inclusion of aluminium in the medium established an inverse relationship between aflatoxin and lipid production. At lower concentrations aluminium stimulated aflatoxin production, whereas at higher concentrations it stimulated total lipid production. Nickel at higher concentrations resulted in an increase in total aflatoxin production. However, no definite correlation was observed between total aflatoxin and total lipid production when nickel was included in the medium. *** DIRECT SUPPORT *** A00FP116 00002
Function of terminal acceptors in the biosynthesis of denitrification pathway components inParacoccus denitrificansKučera, I.; Boublíková, P.; Dadák, V.
doi: 10.1007/bf02872925pmid: N/A
Limited aeration of cell suspension in growth medium was used to study the kinetics of formation of nitrite reductase and nitrous-oxide reductase and their physiological electron donor, cytochromec-550, during the anaerobic adaptation ofParacoccus denitrificans. The crucial step in the regulation of synthesis of these components is the repressive effect of oxygen while nitrogenous acceptors (NO3−, NO2−, N2O) probably play no role as inducers. The time course of the enzyme activites was analogous (after a lag phase a sharp increase with a maximum after 3 h) and differed from the kinetics of synthesis of cytochromec-550 (gradual rise throughout the 8-h experiment).
Lysis of growing cells ofSaccharomyces cerevisiae induced by papulacandin BKopecká, M.
doi: 10.1007/bf02872926pmid: 6373523
Light and electron microscopy was used to study the effect of papulacandin B onSaccharomyces cerevisiae in the exponential growth phase. At 1–2 μg/mL cell division in the culture continued almost in parallel with the control, at 4 μg/mL cell proliferation was reduced and the culture contained some cells with 2–9 buds which were not separated from the mother cell by a septum, and at higher concentrations (8, 16 and 32 μg/mL) the proliferation stopped within 2 h. Cessation of proliferation was due to lysis of budding cells in the bud region including perforation of thinned cell wall (most often at the bud basis and sometimes at its apex), extrusion of cytoplasm and death of cell. Lysis was also observed in cells without visible buds. Dividing cells died without visible lysis.
Effect ofAgrobacterium radiobacter and its polysaccharide on emergence and damping-off of tomato plantsFresnedo, J. A.; Kaňková, J.; Řičica, J.; Staněk, M.
doi: 10.1007/bf02872927pmid: N/A
Agrobacterium radiobacter B6 and agrobacteran (an exopolysaccharide of the succinoglycan group) stimulated seed germination and tomato plant emergence. The germination was most stimulated by dipping the seeds in 0.1 % agrobacteran for 30 min whereas plant emergence in garden soil was best with 0.4 % agrobacteran at 10–20°C. Treatment of the plants withA.radiobacter cells and agrobacteran solution at 30–35°C. had a lower effect.A.radiobacter cells applied on seed surface protected the plants against damping off in garden soil artificially inoculated with the fungiRhizoctonia solani andPythium ultimum; in soils contaminated withFusarium solani 0.1 to 0.2% agrobacteran had a higher protective effect than the bacterization. The difference can be attributed to the varying density ofA.radiobacter population in plant rhizosphere in the presence of different plantpathogenic fungi, different interactions of microorganisms in the rhizosphere and different mode of penetration of the pathogens into plant roots.
Soil heterotrophic bacteria in transformations of inorganic sulphurLettl, A.
doi: 10.1007/bf02872929pmid: N/A
The occurrence of biochemical activities of the sulphur cycle was followed in isolates of heterotrophic bacteria from the fermentative horizon of a spruce stand, a grass-covered withered spruce stand and of mountain ash and birch stand in the area strongly influenced by sulphur immissions. The occurrence of bacteria capable of reducing S0 to S2−, oxidizing S0 and S2O32− to SO42− and solubilizing S0 increased in the above order. The occurrence of producers of thiosulphate sulphurtransferase (rhodanese), thiosulphate oxidase and sulphite oxidase increased and the level of the production of these enzymes increased as well. Heterotrophic bacteria (mostly pseudomonads) from the grass-covered stands exhibit more activities of the sulphur cycle than bacteria from the spruce stand without ground vegetation.
The impedance method for monitoring total coliforms in wastewatersTenpenny, J. R.; Tanner, R. D.; Malaney, G. W.
doi: 10.1007/bf02872934pmid: 6373525
An impedance technique is presented as a method which offers promise as a test for estimating the numbers of total coliform bacteria in wastewaters. The technique reported here has the advantage of being 3–4 times faster than the standard membrane filter method (i.e. 4–7 h, compared with 20–24 h). The technique shows the disadvantages of (a) being markedly higher in initial cost of instrumentation, (b) being somewhat more expensive in required supplies, and (c) giving results which deviate considerably from the values given by the MF method. A parallel use of the impedance and MF methods when both speed and accuracy are desired may be an appropriate practical compromise.