Exogenous Ribonuclease in the Improvement of Lactobacillus Biological Properties

The influence of exogenous RNAase on the dynamics of the acid formation by the industrial strain 8R-A3 of Lactobacillus plantarum, its antibiotic sensitivity and antagonistic activity was studied. In the presence of the RNAase growth stimulating dose both a decrease of the culture lag-phase and a more intensive accumulation of lactic acid in the incubation medium resulting in an increase of the Lactobacillus antagonistic activity were observed. It was shown that RNAase increased the Lactobacillus stability to tetracycline and erythromycin by 32 to 57 per cent as compared to the control

The quarantine control and the methods of disinfection of tomato and cucumber seeds in different regions of Russian Federation

Quarantine phytopathogenic analysis of different sorts of tomato and cucumber seeds used in greenhouses in Russian Federation was studied. The common number of fungi and bacteria colonizing the outside and inside of seeds were determined. The characterization of micromycetes and bacteria complex disseminating the seeds was established. The phytotoxic infectious microorganisms were isolated. The negligible effect of some physical and chemical factors in seeds disinfectant was shown. The high antagonistic activity against phytopathogens as a new method of biocontrol with Trichoderma harziamum was proposed

Initial stages of 2,4,6-trinitrotoluene transformation by microorganisms

Screening of a wide range of microorganisms (32 strains) isolated from various anthropogenic and natural environments and of a number of collection strains showed that the early stages of 2,4,6-trinitrotoluene (TNT) transformation by the majority of the strains studied resulted in the formation of hydroxylaminodinitrotoluenes (HADNTs). The levels of HADNTs were in a number of cases comparable to the initial TNT level. The alternative reductive attack on TNT through the reduction of the aromatic ring was not characteristic of most of the prokaryotes studied. The susceptibility to the toxic effect of TNT was different for gram-positive and gram-negative bacteria

Initial stages of 2,4,6-trinitrotoluene transformation by microorganisms

Screening of a wide range of microorganisms (32 strains) isolated from various anthropogenic and natural environments and of a number of collection strains showed that the early stages of 2,4,6-trinitrotoluene (TNT) transformation by the majority of the strains studied resulfed in the formation of hydroxylaminodinitrotoluenes (HADNTs). The levels of HADNTs were in a number of cases comparable to the initial TNT level. The alternative reductive attack at TNT through the reduction of the aromatic ring was not characteristic of most of the prokaryotes studied. The susceptibility to the toxic effect of TNT was different for gram-positive and gram-negative bacteria

Models of 2,4,6-trinitrotoluene (TNT) initial conversion by yeasts

The original models of the initial steps of 2,4,6-trinitrotoluene (TNT) conversion by yeasts are presented. Saccharomyces sp. ZS-A1 reduced nitro groups of TNT producing isomeric monohydroxylaminodinitrotoluenes (HADNT) as the key initial metabolites (molar ratio HADNT/TNT was up to 0.81), whereas aminodinitrotoluenes (ADNT) and the hydride-Meisenheimer complex of TNT (H-TNT) were the minor products. Conversely, Candida sp. AN-L13 transformed TNT almost quantitatively into H-TNT, thus realizing the alternative attack, consisting of the TNT aromatic ring reduction. The third type of conversion, revealed in Candida sp. AN-L14, is the combination of both above mechanisms and produces an equimolar mix of HADNT and H-TNT. In the toxicity tests with Paramecium caudatum, the supernatant of Saccharomyces sp. ZS-A1, which converts TNT into HADNT, was most toxic while the supernatant of Candida sp. AN-L13 (TNT→H-TNT) was least toxic. The microorganisms converting TNT quantitatively to the reactive metabolites can be useful for their immobilization through the detoxifying interaction with the soil components such as humic compounds. © 2002 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved

Metal binding induces conversion of B- to the hybrid B-Z-form in natural DNA

Highly polymerized herring testis DNA of the random nucleotide sequence has been studied in solution by circular dichroism and ultra-violet absorption spectrometry under various experimental conditions. At low temperature upon addition of 0.05 M NaCl or 1.15 M MgSO4 the DNA formed a helix that belonged to the B-family. As the temperature was increased a transition from the pure B- to the hybrid B-Z-form occurred in the presence of 1.15 M MgSO4. This transition occurred over a large range of temperatures and corresponded to a non-cooperative conformational change. A similar DNA transition was induced with 0.098 mM Co(NH3)6Cl3. However, in the presence of 5.3 M NaCl the DNA conformation was not similar to that observed in 1.15 M MgSO4 or 0.098 mM Co(NH3)6Cl3 independently on the environmental temperature. In 5.3 M NaCl the DNA is thought to undergo a transition from one to another right-handed conformation that could be intermediate partially dehydrated conformer arising on the first step in the sequential transition to the dehydration of the polynucleotide. Our results show that a realistic model of native DNA, bearing Z-tracts embedded in B-helixes, can be obtained upon binding of alkaline earth or transition metals. © 2008 Elsevier B.V. All rights reserved

Distribution and physiological state of microorganisms in petrochemical oily sludge

The occurrence, vertical distribution, and physiological state of microorganisms in a petrochemical oily sludge deposit were studied. The total number and the number of viable microbial cells at depths of 0.2 and 3 m were about 1010 and 108 cells/g dry wt sludge. Most microbial cells taken from the middle (l m deep) and the bottom (3 m deep) sludge horizons showed a delayed colony-forming ability, which suggested that the cells occurred in a hypometabolic state. The relative number of microaerobic denitrifying microorganisms steeply increased with depth. The amount of microorganisms tolerant to 3, 5, and 10% NaCl and capable of growing at 7 and 40 °C varied from 102 to 108 CFU/g dry wt sludge. Petrochemical oily sludge was found to maintain the growth of heterotrophs, among which the degraders of oily sludge and ten different individual polycyclic aromatic hydrocarbons were detected. The occurrence of highly adaptable microorganisms with an adequate metabolic potential in the petrochemical oily sludge deposit implies that its bioremediation is possible without introducing special microorganisms

Metal binding induces conversion of B- to the hybrid B-Z-form in natural DNA

Highly polymerized herring testis DNA of the random nucleotide sequence has been studied in solution by circular dichroism and ultra-violet absorption spectrometry under various experimental conditions. At low temperature upon addition of 0.05 M NaCl or 1.15 M MgSO4 the DNA formed a helix that belonged to the B-family. As the temperature was increased a transition from the pure B- to the hybrid B-Z-form occurred in the presence of 1.15 M MgSO4. This transition occurred over a large range of temperatures and corresponded to a non-cooperative conformational change. A similar DNA transition was induced with 0.098 mM Co(NH3)6Cl3. However, in the presence of 5.3 M NaCl the DNA conformation was not similar to that observed in 1.15 M MgSO4 or 0.098 mM Co(NH3)6Cl3 independently on the environmental temperature. In 5.3 M NaCl the DNA is thought to undergo a transition from one to another right-handed conformation that could be intermediate partially dehydrated conformer arising on the first step in the sequential transition to the dehydration of the polynucleotide. Our results show that a realistic model of native DNA, bearing Z-tracts embedded in B-helixes, can be obtained upon binding of alkaline earth or transition metals. © 2008 Elsevier B.V. All rights reserved

Distribution and physiological state of microorganisms in petrochemical oily sludge

The occurrence, vertical distribution, and the physiological state of microorganisms in a petrochemical oily sludge deposit were studied. The total number and the number of viable microbial cells at depths of 0.2 and 3 m were about 10 and 108 cells/g dry wt. sludge. Most microbial cells taken from the middle (1 m deep) and the bottom (3 m deep) sludge horizons showed a delayed colony-forming ability, which suggested that the cells occurred in a hypometabolic state. The relative number of microaerobic denitrifying microorganisms steeply increased with depth. The amount of microorganisms tolerant to 3, 5, and 10% NaCl and capable of growing at 7 and 40°C varied from 102 to 108 CFU/g dry wt. sludge. Petrochemical oily sludge was found to maintain the growth of heterotrophs, among which the degraders of oily sludge and ten different individual polycyclic aromatic hydrocarbons were detected. The occurrence of highly adaptable microorganisms with an adequate metabolic potential in the petrochemical oily sludge deposit implies that its bioremediation is possible without introducing special microorganisms

Isolation and properties of extracellular alkaline phosphatase from Bacillus intermedim

Alkaline phosphatase (APase) was isolated from the culture liquid of the streptomycin-resistant strain of Bacillus intermedius S3-19 and purified as a homogeneous preparation by ion-exchange chromatography and FPLC. Electrophoresis and gel-nitration revealed that the active enzyme is a monomer with molecular weight of 46-47 kD. The enzyme possessed phosphomonoesterase and phosphodiesterase activities with maximal levels at pH 9.5 and 55°C and was stable until 60°C at pH 8.0-10.0. The isolated APase exhibits a broad specificity towards a wide variety of substrates. The effect of divalent metal ions and other reagents on its catalytic activities was studied. It was concluded that alkaline phosphatase of B. intermedius is similar to the secreted alkaline phosphatases from other Bacillus species in its physicochemical and catalytic properties