Sensitivity of various escherichia coli strains to 2,4,6-trinitrotoluene

The sensitivity of Escherichia coli strains K-12 and 055 to 2,4,6-trinitrotoluene (TNT) was found to correlate with the structural and functional properties of the outer lipoprotein membrane. The protective ability of the membrane of strain 055 is much lower than that of K-12. This is the cause of the greater sensitivity of 055 to the toxic action of TNT. High TNT concentrations (100-200 mg/l) suppressed the growth of 055, whereas K-12 grew at all TNT concentrations studied. Both strains adapted to high TNT concentrations by converting it by either nitroreduction or denitritation depending on concentration. The denitritation system of strain 055 started TNT degradation earlier than that of K-12.     

The effect of ampicillin on the electrophysical properties of Escherichia coli cells

The study of the effect of ampicillin on the electrophysical properties of Escherichia coli cells showed that this antibiotic influences the orientational spectra (OSs) of the ampicillin-susceptible E. coli strains K-12 and XL-1 within the frequency range 10–1000 kHz of the orienting electric field and does not affect the OSs of the ampicillin-resistant strains K-12(pUC-18) and XL-1(pHEN1). The change in the electrooptical signal of the ampicillin-susceptible cells was maximum at an ampicillin concentration of 50 µg/ml and did not depend on the exposure time. The conclusion is drawn that changes in the OSs of cells can be used to evaluate their resistance to ampicillin.Translated from Mikrobiologiya, Vol. 74, No. 1, 2005, pp. 126–131.Original Russian Text Copyright © 2005 by Guliy, Markina, Ignatov, Shchegolev, Zaitseva, Bunin, Ignatov.     

The chemotactic characteristics of the S and R dissociants of <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis>

The chemotactic responses of Bacillus thuringiensis subsp. dendrolimus (strain 49) and thuringiensis (strain 2002) and their morphological dissociants were studied by using some natural and artificial substances as effectors. The 12-h-old wild-type cells (S variants) of both strains were found to be motile and similar in their chemotactic responses, whereas the chemotactic responses of the R variants were different.Translated from Mikrobiologiya, Vol. 74, No. 1, 2005, pp. 87–91.Original Russian Text Copyright © 2005 by Lebenko, Sekerina, Chemerilova.     

Structural Characteristics and Biological Properties of <Emphasis Type="Italic">Pseudomonas fluorescens</Emphasis> Lipopolysaccharides

The structure and biological properties of lipopolysaccharides (LPSs) from strains IMB 4125 (=ATCC 13525) and IMB 7769 of the bacterium Pseudomonas fluorescens (biovar I) were studied in vitro. LPSs were similar in the composition of lipid A and the core lipid but differed in the structure of O-specific polysaccharide chains, which was corroborated by the absence of serological relationships between them. The toxicity (LD₅₀) of LPSs of P. fluorescens with respect to D-glucosamine-sensitized mice was 40–50 times lower than the toxicity of the classic endotoxins, LPSs of E. coli. The LPSs studied stimulated the production of tumor necrosis factor (TNF) and nitric oxide (NO) by mouse peritoneal macrophages. The rates of TNF and NO synthesis induced by the LPSs of interest were eight to nine and three to five times lower, respectively, than the corresponding parameters of the control LPSs of E. coli 055:B5 and 026:B6._Additionally, LPS preparations of the P. fluorescens strains induced TNF synthesis by monocytes of human whole-blood preparations. Certain differences in biological properties of these strains have been revealed, which could be due to the characteristic features of LPS structure and composition in different cultures.__________Translated from Prikladnaya Biokhimiya i Mikrobiologiya, Vol. 41, No. 4, 2005, pp. 414–421.Original Russian Text Copyright © 2005 by Veremeichenko, Vodyanik, Zdorovenko.     

Lipid Composition of Cells of Heterothallic Strains in the Developmental Cycle of <Emphasis Type="Italic">Blakeslea trispora</Emphasis>

Lipid compositions in mycelium and spores of Blakeslea trispora heterothallic strains were studied. Distinctions between the strains in the ability to synthesize linolenic acid and in optimal growth temperature were demonstrated. The (−) strain grew at a higher temperature and was unable to synthesize linolenic acid, whereas the (+) strain accumulated this acid up to 20% of total fatty acids. The distinctions between the strains remained at different developmental stages (mycelium and spores). A higher thermotolerance of the (−) strain correlated with a high sterol content, which is typical of thermophilic fungi. The lipid compositions of heterothallic strains studied differed in lipid content, their fractional composition, the degree of unsaturation, and carotenoid composition.__________Translated from Prikladnaya Biokhimiya i Mikrobiologiya, Vol. 41, No. 4, 2005, pp. 449–453.Original Russian Text Copyright © 2005 by Tereshina, Memorskaya, Feofilova.     

R-Plasmid Transfer to and from Escherichia coli Strains Isolated from Human Fecal Samples

Strains of Escherichia coli recently isolated from human feces were examined for the frequency with which they accept an R factor (R1) from a derepressed fi⁺ strain of E. coli K-12 and transfer it to fecal and laboratory strains. Colicins produced by some of the isolates rapidly killed the other half of the mating pair; therefore, conjugation was conducted by a membrane filtration procedure whereby this effect was minimized. The majority of fecal E. coli isolates accepted the R factor at lower frequencies than K-12 F⁻, varying from 10⁻² per donor cell to undetectable levels. The frequencies with which certain fecal recipients received the R-plasmid were increased when its R⁺ transconjugant was either cured of the R1-plasmid and remated with the fi⁺ strain or backcrossed into the parental strain. The former suggests the loss of an incompatibility plasmid, and the latter suggests the modification of the R1-plasmid deoxyribonucleic acid (DNA). In general, the fecal R⁺E. coli transconjugants were less effective donors for K-12 F⁻ and heterologous fecal strains than was the fi⁺ K-12 strain, whereas the single strain of Citrobacter freundii examined was generally more competent. Passage of the R1-plasmid to strains of salmonellae reached mating frequencies of 10⁻¹ per donor cell when the recipient was a Salmonella typhi previously cured of its resident R-plasmid. However, two recently isolated strains of Salmonella accepted the R1-plasmid from E. coli K-12 R⁺ or the R⁺E. coli transconjugants at frequencies of 5 × 10⁻⁷ or less.     

Degradation of phenol and toxicity of phenolic compounds: a comparison of cold-tolerant<Emphasis Type="Italic"> Arthrobacter</Emphasis> sp. and mesophilic<Emphasis Type="Italic"> Pseudomonas putida</Emphasis>

Phenol degradation efficiency of cold-tolerant Arthrobacter sp. AG31 and mesophilic Pseudomonas putida DSM6414 was compared. The cold-tolerant strain was cultivated at 10°C, while the mesophile was grown at 25°C. Both strains degraded 200 mg and 400 mg phenol/l within 48–72 h of cultivation, but the cold-tolerant strain produced more biomass than the mesophile. Both strains oxidized catechol by the ortho type of ring fission. Catechol 1,2 dioxygenase (C1,2D) activity was found intra- and extracellularly in the absence and in the presence of phenol. In the presence of 200 mg phenol/l, C1,2D activity of the mesophile was about 1.5- to 2-fold higher than that of the cold-tolerant strain. However, an initial phenol concentration of 400 mg/l resulted in a comparable enzyme activity of the cold-tolerant and the mesophilic strain. The two strains differed significantly in their toxicity pattern towards 12 aromatic (mostly phenolic) compounds at different growth temperatures, which was determined via growth inhibition in the presence of nutrients and toxicants. For the cold-tolerant strain, toxicity was significantly lower at 10°C than at 25°C. The mesophile showed a significantly lower susceptibility to high hydrocarbon concentrations when grown at 25°C compared to 10°C.Communicated by K. Horikoshi     

Possible Reasons for Difference in Sensitivity to Oxygen of Two <Emphasis Type="Italic">Escherichia coli</Emphasis> Strains

In preliminary experiments it was found that Escherichia coli strains AB1157 and KS400 are different in their abilities to grow under various oxygen levels in cultivation medium: the first strain does not grow under high oxygen conditions, unlike the second one. To investigate whether the damage to cellular components due to production of reactive oxygen species (ROS) was responsible for this difference, the intensity of free radical oxidation of proteins and lipids as well as the activities of selected antioxidant and associated enzymes (superoxide dismutase, catalase, peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase) were compared in the two strains. The level of thiobarbituric acid-reactive substances was 1.8–2.5-fold higher in AB1157 than in KS400, but the concentration of carbonyl proteins was lower in the AB1157 strain. In both strains growth under higher oxygen levels resulted in higher superoxide dismutase and peroxidase activities in both exponential and stationary phases. Overall, the activities of antioxidant enzymes were always higher in the KS400 strain than in AB1157. The results for both lipid and protein oxidative damage and antioxidant enzyme activities suggest that the differences in oxygen tolerance between these two strains may be due to their different abilities to cope with ROS.__________Translated from Biokhimiya, Vol. 70, No. 4, 2005, pp. 514–522.Original Russian Text Copyright © 2005 by Semchyshyn, Lushchak, Storey.     

Effect of culture medium composition on the activity of extracellular lectins of <Emphasis Type="Italic">Lentinus edodes</Emphasis>

The time course of lectin production in culture liquid of the basidial fungus Lentinus edodes strain F-249 in different media under submerged culture conditions was studied. The activity of agglutinins depended on the ratio between carbon and nitrogen sources and the pH of the culture medium. The lectin activity in culture medium was maximal when the fungus was grown in a medium containing L-arabinose as a source of carbon and L-asparagine as a source of nitrogen (C:N ratio, (9.5–12):1) on day 15–18 of culturing at pH 8.0–9.0.Translated from Prikladnaya Biokhimiya i Mikrobiologiya, Vol. 41, No. 2, 2005, pp. 200–203.Original Russian Text Copyright © 2005 by Tsivileva, Nikitina, Garibova.     

Temperate Bacteriophage Which Causes the Production of a New Major Outer Membrane Protein by Escherichia coli

Under most conditions of growth, the most abundant protein in the outer membrane of most strains of Escherichia coli is a protein designated as “protein 1” or “matrix protein”. In E. coli B, this protein has been shown to be a single polypeptide with a molecular mass of 36,500 and it may account for more than 50% of the total outer membrane protein. E. coli K-12 contains a very similar, although probably not identical, species of protein 1. Some pathogenic E. coli strains contain very little protein 1 and, in its place, make a protein designated as protein 2 which migrates faster on alkaline polyacrylamide gels containing sodium dodecyl sulfate and which gives a different spectrum of CNBr peptides. An E. coli K-12 strain which had been mated with a pathogenic strain was found to produce protein 2, and a temperate bacteriophage was isolated from this K-12 strain after induction with UV light. This phage, designated as PA-2, is similar in morphology and several other properties to phage lambda. When strains of E. coli K-12 are lysogenized by phage PA-2, they produce protein 2 and very little protein 1. Adsorption to lysogenic strains grown under conditions where they produce little protein 1 and primarily protein 2 is greatly reduced as compared to non-lysogenic strains which produce only protein 1. However, when cultures are grown under conditions of catabolite repression, protein 2 is reduced and protein 1 is increased, and lysogenic and non-lysogenic cultures grown under these conditions exhibit the same rate of adsorption. Phage PA-2 does not adsorb to E. coli B, which appears to have a slightly different protein 1 from K-12. These results suggest that protein 1 is the receptor for PA-2, and that protein 2 is made to reduce the superinfection of lysogens.     

Direct fermentation of various pure and crude starchy substrates to L(+) lactic acid using Lactobacillus amylophilus GV6

Lactobacillus amylophilus GV6 fermented a variety of pure and natural starches directly to L(+) lactic acid. Starch to lactic acid conversion efficiency was more than 90% by strain GV6 at low substrate concentrations with all starches. The strain GV6 produced high yields of lactic acid per g of substrate utilized with pure starches such as soluble starch, corn starch, and potato starch, yielding 92–96% at low substrate concentrations in 2 days and 78–89% at high substrate (10%) concentrations in 4–6 days. Strain GV6 also produced high yields of lactic acid per g of substrate utilized with crude starchy substrates such as wheat flour, sorghum flour, cassava flour, rice flour and barley flour yielding 90–93% at low substrate concentrations in 2 days and 80% or more at high substrate concentrations in 6–7 days. Lactic acid yields by L. amylophilus GV6 with pure starches were comparable when low cost crude starchy substrates were used. Lactic acid productivity by strain GV6 is higher than for any other previously reported strains of L. amylophilus.     

A correlation between sensitization to gamma-rays by purine starvation and the rec genes in Escherichia coli K-12

Summary After purine staration the recombination proficient (Rec⁺) strains of E. coli K-12 tested were sensitized to inactivation by gamma-rays (Figs. 1–4). No such change was noted in the Rec^– strains tested (Fig. 5). These results suggest that purine starvation may sensitize cells to ionizing radiation by inhibiting repair controlled by the recA, recB and recC genes.This paper was reported in part at the Fourteenth Annual meeting of the Biophysical Society in Baltimore, Md., 25–27 February 1970.     

Semicontinuous penicillin production by two Penicillium chrysogenum strains immobilized in calcium alginate beads

Summary The growth rates of immobilized Penicillium chrysogenum strains are important in their application to semicontinuous penicillin production. Immobilized P. chrysogenum strains produced about 10–15% less biomass but about 1–2 times more penicillin than free suspended mycelia.In a chemically defined medium an industrial P. chrysogenum strain, S₁, produced about 10–12 times more penicillin than strain ATCC 12690. In a complex medium the immobilized P. chrysogenum S₁ produced about 12% penicillin more than in shaken cultures. In bubble column fermentations, penicillin production was 163% higher in the complex medium than in the chemically defined medium.     

The role of membrane lipids in the resistance of clapsing-leaved pondweed (<Emphasis Type="Italic">Potamogeton perfoliatus</Emphasis> L.) to excess of cadmium in water

The effect of cadmium on clapsinng-leaved pondweed (Potamogeton perfoliatus L.) within the concentration range of 1–1000 µM was studied. It was shown that P. perfoliatus leaves accumulated cadmium during three days. This process was accompanied by changes in leaf morphology. The sensitivity of biochemical metabolites to cadmium was different. Low concentrations of cadmium (1 and 10 µM) increased the content of protein, total lipids, and photosynthetic pigments, whereas high concentrations (100 and 1000 µM) decreased the content of total lipids and pigments but increased protein content. Based on cadmium sensitivity, structural lipids were divided into three groups—resistant (neutral, phosphatidylglycerol, digalactosyldiacylglycerol, and sulfolipid), the content of which increased in the presence of cadmium; labile (monogalactosyldiacylglycerol, phosphatidylcholine, and phosphatidylinositol); and nonresistant (phosphatidylethanolamine). It is concluded that the lipid component determines the resistance of P. perfoliatus to cadmium.Translated from Izvestiya Akademii Nauk, Seriya Biologicheskaya, No. 2, 2005, pp. 232–239.Original Russian Text Copyright © 2005 by Rozentsvet, Murzaeva, Gushchina.     

Structure of the sulfur inclusion envelopes from four beggiatoas

The sulfur inclusions from four strain ofBeggiatoa alba were observed by using a ruthenium red-glutaraldehyde technique and a modified Ryter-Kellenberger technique. Three of the four strains contained 4-to 5-nm-thick, single, electron-dense, layered sulfur inclusion envelopes. The fourth strain (B15LD) contained a complex pentalaminar sulfur inclusion envelope, 12–14 nm thick. The sulfur inclusions from all four strains were external to the cytoplasmic membrane but internal to the complexBeggiatoa cell walls. Freeze-etching of theB. alba strain B18LD trichomes revealed the unusual cross-fracture morphology of the sulfur in the inclusions. Fractures around the sulfur inclusions revealed a surface similar to that of the fractured cytoplasmic membrane.     

Conjugative Transfer of the Large Plasmid p19 in Various <Emphasis Type="Italic">Bacillus subtilis</Emphasis> Strains

Cryptic conjugative plasmid p19 from the environmental Bacillus subtilis strain 19 was labeled with the cat gene conferring resistance to chloramphenicol. The resulting plasmid, p19cat, was used to estimate the transfer frequency, to study the dynamics of plasmid transfer, and to detect some specific features of conjugation between various B. subtilis strains.__________Translated from Genetika, Vol. 41, No. 5, 2005, pp. 601–606.Original Russian Text Copyright © 2005 by Poluektova, Fedorina, Prozorov.     

Survival, mutation and capacity to repair single-strand DNA breaks after gamma irradiation in different Exr? strains of Escherichia coli

Summary Strains of Escherichia coli K-12 and B/r made by transduction of the exrA allele from a B_s-2 derivative have been compared with Exr(W)^– strains derived from B_s-1 and B_s-2 by mutation (E.M. Witkin, 1967). Both transduced exrA and Exr(W)^– strains were almost unmutable by gamma radiation, but the former class were as sensitive to gamma radiation as recA strains and, like them, were unable to repair single-strand DNA breaks as detected by the McGrath-Williams technique. In contrast the Exr(W)^–strains were as resistant to gammaradiation as Exr(W)⁺ strains derived from them and were equally efficient in repairing single-strand breaks. The existence of Exr(W)^–strains suggests that the mutagenicity of single-strand breaks may depend entirely on the way in which they are repaired. The properties of the (Exr(W)^–strains cannot be ascribed solely to the transducable exrA allele.A large effect of diffuse daylight in lowering the molecular weight of DNA on alkaline sucrose gradients is described which, unless prevented, may lead to erroneous results in such experiments.     

Distribution of Coliphages Against Four <Emphasis Type="Italic">E. Coli</Emphasis> Virotypes in Hospital Originated Sewage Sample and a Sewage Treatment Plant in Bangladesh

The distribution of coliphages infecting different Escherichia coli virotypes (EHEC, EIEC, EPEC, ETEC) and an avirulent strain (K-12) in sewage system of a hospital and a sewage treatment plant (STP) was investigated by culture-based agar overlay methods. Coliphages were found in all the samples except stool dumping site in the sewage system of the hospital and lagoon of the STP. Bacteriophage count (pfu/ml) infecting E. coli strains showed the following ascending pattern (EHEC < EIEC < EPEC < ETEC < E coli K-12) in all the collected samples except one. Phages capable of infecting avirulent E. coli K-12 strains were present in the highest number among all the examined locations. Phages specific for E. coli K-12 presented high diversity in plaque size on the bacterial lawn. Virulent E. coli specific coliphages rarely produced plaques with diameter of 1–2 mm or over. Conventional agar overlay method was found to be not satisfactory for phage community analysis from primary stool dumping site of the hospital, probably due to the presence of high concentration of antimicrobial substances. The gradual decrease seen in the five groups of coliphage quantity with the ongoing treatment process and then the absolute absence of coliphages in the outlet of the examined treatment plant is indicative of the usefulness of the treatment processes practiced there.     

Mycelial growth of strains of the genera <Emphasis Type="Italic">Suillus</Emphasis> and <Emphasis Type="Italic">Boletinus</Emphasis> in media with a wide range of concentrations of carbon and nitrogen sources

Suillus and Boletinus were studied using Ohta medium. In media with glucose or trehalose, all tested strains grew well. With mannose and cellobiose, strains generally grew well, except for one strain of Suillus. Utilization of dextrin and soluble starch differed with each strain, and that of sucrose and glycerol was low for all strains. Utilization of four amino acids, arginine, glutamic acid, aspartic acid, and alanine, was similar to that of ammonium tartrate for Suillus strains, but mycelial growth with amino acids was clearly lower than with ammonium tartrate for the Boletinus strain. The effect of glucose and ammonium tartrate concentrations for nine strains of the genera Suillus and Boletinus was studied with ranges for glucose of 1–100 and 200g/l, respectively, and for ammonium tartrate of 0.2–5 and 20g/l, respectively. Six strains showed maximal growth at a glucose concentration greater than 25g/l, and one strain showed maximal growth at 70g/l. The results indicate that these fungi are adapted to relatively high concentrations of carbon sources. In general, glucose concentration at mycelial growth maximum decreased as ammonium tartrate concentration increased, and at higher concentrations of glucose, mycelial growth decreased more rapidly in higher concentrations of ammonium tartrate.     

Multiplicity of chemical mechanisms of regulation of muscle contractions in <Emphasis Type="Italic">Lymnaea stagnalis</Emphasis> L.

Effects of acetylcholine, octopamine, and their antagonists, as well as of glutamic acid were studied on contractions of dorsal longitudinal muscle of the mollusc Lymnaea stagnalis L., evoked by electrical stimulation of n. cervicalis inferior. Acetylcholine and octopamine increased amplitude of contractions evoked by applications at concentrations about 10^–8 M and decreased at concentrations higher than 10^–7 M. Glutamic acid produced only inhibitory effect on the contraction amplitude, which appeared at concentrations beginning from 10^–9 M and higher. The acetylcholine antagonists atropine and d-tubocurarine also decreased amplitude of evoked contractions. Their blocking effect rose with increase of their concentrations in the range from 10^–9 M to 10^–5 M. Specificity of the effect of the studied substances was established in experiments with a combined application of the transmitters and their antagonists. The obtained results indicate multiplicity of chemical mechanisms of regulation of contractions of the dorsal longitudinal muscle in L. stagnalis.Translated from Zhurnal Evolyutsionnoi Biokhimii i Fiziologii, Vol. 41, No. 1, 2005, pp. 44–50.Original Russian Text Copyright © 2005 by Kononenko, Zhukov.