bluuebunny/crossref_metadata_2025 huggingface dataset:
Actions antibiotique, mycolytique et parasitaire de deux actinomycètes envers Fusarium oxysporum f.sp. albedinis et autres formae speciales
Authors: Sabaou Nasserdine , Bounaga Nicole , Bounaga Djilali
Published: May 2010

Two actinomycètes (X9 and X10) isolated on a Fusarium oxysporum f.sp. albedinis strain showed antibiotic, mycolytic, and parasitism actions against nine "formae speciales" of Fusarium oxysporum. Strain X10 is included in genus Streptomyces and strain X9 in Nocardiopsis dassonvillei species (Lechevalier and Lechevalier) Meyer. The antibiotic action of Streptomyces strain is stronger towards F. o. dianthi, F. o. albedinis, and F. o. cyclaminis. It seems that the mycolytic power of N. dassonvillei is more specific to F. o. eleaidis, whereas the parasitism action varies depending on the "formae speciales" tested and the quantity of fungal mycelium produced. As a response to this parasitism, all the fungi produce resistance organs that can either be polymorphous thallospores or chlamydospores. The thallospores studied on a F. o. albedinis strain germinate faster than the microconidies of the same nonparasited fungus. However, many strains obtained from these thallospores are as susceptible as the mother strain to the antagonistic action of both actinomycetes
Nitrogen isotope fractionation during the reduction of NO3− to NH4+ by Desulfovibrio sp.
Authors: McCready R. G. L. , Gould W. D. , Barendregt R. W.
Published: May 2010

Desulfovibrio reduce NO3−to NH4+ via a dissimilatory pathway. In 21 days, four strains of Desulfovibrio reduced 36–48% of the available NO3− to ammonium. During this reductive process extensive nitrogen isotope fractionation occurred: the product NH4+ was enriched in 15N in the initial sample, then became enriched in 14N to a minimum value at approximately 20–25% reaction, and then became isotopically heavier as the reaction proceeded.
Survival in foods of Staphylococcus aureus grown under optimal and stressed conditions and the effect of some food preservatives
Authors: El-Banna A. A. , Hurst A.
Published: May 2010

Staphylococcus aureus was grown in a rich peptone medium which became alkaline with continued incubation. Cells were grown at 37 °C and in the same medium containing 1 M NaCl at 46 °C, a temperature at which this organism can grow only when protected by NaCl. Cells of these cultures are hereafter called 37 °C-cells and 46 °C-cells, respectively. The 37 °C-cells harvested when the pH was 7.1 to 7.7 had decimal reduction times (D60-value) of 1.8 to 3.1 min in 50 mM pH 7.2 Tris buffer. The D60 value of 46 °C-cells tested in the same way, harvested from cultures at pH 6.6 to 7.6, ranged from 5.3 to a maximum of 12.8 min. In milk, green beans, peas, or beef slurry, the D60- value of 46 °C-cells was about four times higher than that of 37 °C-cells. Length of survival after freeze-drying in skim-milk powder exposed to air was longest for the cells with the highest D-value. In freeze-dried peas and media acidified with acetic and lactic acids, 46 °C-cells survived longer than 37 °C-cells. However, the sensitivity of the two kinds of cells to potassium sorbate, sodium benzoate, and sodium propionate was essentially the same, but the 46 °C-cells were more resistant to butylated hydroxyanisole and sodium nitrite.
Anaerobic nitrate-dependent chemolithotrophic growth by Rhizobium japonicum
Authors: Neal John L. , Allen George C. , Morse Ronald D. , Wolf Dale D.
Published: May 2010

A hydrogen-uptake-positive strain of Rhizobium japonicum (6-3I1b6) was demonstrated to grow in absence of oxygen chemolithotrophically, utilizing nitrate as the electron acceptor. Dissimilatory nitrate reduction occurred during growth, as evidenced by the disappearance of nitrate from the medium and production of nitrous oxide. Rhizobium japonicum 120-3I1b120, a hydrogen-uptake-negative strain, showed little or no growth under anaerobic chemolithotrophic growth conditions and did not evolve nitrous oxide. A nitrate-dependent hydrogen-uptake and an oxygen-dependent hydrogen-uptake system was present in cells of strain 6-3I1b6 grown chemolithotrophically under anaerobic conditions with nitrate serving as the electron acceptor.
Natural immunity to murine gonococcal bacteremia: roles of complement, leucocytes, and sex
Authors: Streeter P. R. , Wunderlich A. C. , Corbeil R. R. , Corbeil L. B.
Published: May 2010

The roles of the serum bactericidal system, inflammatory cells, and sex in resisting gonococcal infection were studied in a murine model of gonococcal bacteremia. The role of serum killing in defense was investigated with complement component 5 deficient (C5-deficient) (B1O.D2/OSN) and normal (B1O.D2/NSN) mice. No significant differences were found between LD50's with either murine serum-sensitive or serum-resistant gonococci in those two mouse strains. However, in vitro experiments revealed a heat-stable factor in mouse serum which killed gonococci. Thus it appeared that the C5-deficient mouse is not a good model for the study of the role of C-mediated killing in resistance to gonococcal infection. Mice with Chediak–Higashi disease were used to study the role of phagocytes and natural killer cells. The difference in LD50's between affected mice (C57B1/6J beige J) and controls (C57B1/6J) was significant. The CBA/N mice, which have a B-cell maturation defect, were no more resistant to infection than control mice, which was taken as further evidence that B cells were less important than other leucocytes in innate immunity to gonococcal infection. Finally, male mice were significantly more resistant than female mice to gonococcal bacteremia. Thus, in this study the two most important determinants of resistance to gonococcal infection were inflammatory cells and sex.
Reticuloendotheliosis virus-transformed cells contain infectious and noninfectious proviral sequences in different chromosomes
Authors: Franklin Jane Pfeil , Bose Jr. Henry R. , Kang C. Yong
Published: May 2010

The integration site of reticuloendotheliosis virus proviral DNA in the DNA from a cloned reticuloendotheliosis virus-transformed bone marrow cell line was studied. These reticuloendotheliosis virus-transformed bone marrow cells produce a replication-defective transforming virus (REV-T) and a nontransforming helper virus, designated reticuloendotheliosis-associated virus (REV-At). The DNA from this REV-T transformed bone marrow cell line was hybridized with 3H-labeled in vitro synthesized DNA complementary to the reticuloendotheliosis virus (RE) genome to show that these cells contain approximately five genome equivalents per haploid genome. These hybridization experiments did not distinguish between the transforming and nontransforming virus sequences in these cells. Metaphase chromosomes have been isolated from colcemid-treated bone marrow cells and separated into four different size classes on zonal gradients. Hybridization experiment with RE-specific cDNA indicated that all four size classes of chromosomes contain RE-specific sequences. To locate the infectious provirus DNA of the helper virus REV-At, transfection experiments were performed with DNA extracted from the chromosomes of each size class. Infectious REV-At provirus DNA was found principally in one size class. This size class contained the intermediate size macrochromosomes 5 through 11. These results suggest that REV-At proviral DNA must be integrated into a specific chromosome to produce infectious virus.
Effect of growth substrates on fatty acid composition of Corynebacterium cyclohexanicum
Authors: Kaneda Toshi
Published: May 2010

Fatty acids occurring in lipids of Corynebacterium cyclohexanicum are 12-mefhyltridecanoic, myristic, 13-methyltetradecanoic, 12-methyltetradecanoic, n-pentadecanoic, 14-methylpentadecanoic, palmitic, 15-methylhcxadecanoic, and 14-methylhexadecanoic (in order of increasing retention times) identified by gas–liquid chromatographic retention characteristics and mass spectrometry. In glucose-grown cells, 12-methyltetradecanoic (35%) and 14-methylpentadecanoic (35%) acids were major acid components, whereas in the cells grown on cyclohexanecarboxylic, m-hydroxybenzoic, butyric, and acetic acids, 12-methyltetradecanoic acid was always the major cellular fatty acid, constituting 65–81% of the total fatty acids. The phase transition temperature of phospholipid sample from cells grown on glucose (22 °C) was higher than the corresponding values with butyrate (10 °C) and acetate (13 °C). The upper limit of growth temperature, however, was no different between cells grown on butyrate or glucose.
Growth of two serotypes of Nitrobacter in mixotrophic and chemoorganotrophic conditions
Authors: Gay G. , Josserand A. , Bardin R.
Published: May 2010

The influence of organic compounds (pyruvate, yeast extract, and peptone) was tested on two Nitrobacter serotypes. In mixotrophic conditions, these compounds caused swelling of the cells. As shown by immunofluorescence, multiplication of the nitrifying bacteria still occurred in the absence of nitrite. Although growth was slower under such conditions, the organic substrates were used as energy sources. However, the response of the different serotypes studied varied and this could explain the fluctuations of the two nitrifying populations in the soil.
Subcellular location of enzymes involved in leucine dissimilation in Clostridium bifermentans
Authors: Britz Margaret L. , Wilkinson Russell G.
Published: May 2010

Conversion of leucine to isovaleric (iV) and isocaproic (iC) acids by cell-free extracts of Clostridium bifermentans was demonstrated using two lysis procedures. Sonication resulted in an extract which had the enzymes to convert leucine to α-ketoisocaproic acid (α-kiC) and thence iV, but failed to produce iC. Extracts prepared by osmotic lysis, which contained intact membranes, could convert leucine to both iV and iC. The enzyme which converts leucine to α-kiC was solubilized during osmotic lysis, whereas the decarboxylase and leucine reductase system remained membrane bound. Osmotic lysis also released at least two small molecular weight, heat-stable, anionic components (3500 > molecular weight [Formula: see text] 1000), which stimulated decarboxylase activity.
Inhibition de la croissance de populations bactériennes par des suspensions obtenues de Pseudomonas aeruginosa pyocinogéniques
Authors: García-Quintana Héctor G. , Flores M. Elena
Published: May 2010

Suspensions obtained from five Pseudomonas aeruginosa pyocinogenic strains showed inhibitory and variable activity against bacterial strains belonging to the Nocardiaceae, Micrococcaceae, Neisseriaceae, Streptococcaceae, Vibrionaceae, Enterobacteriaceae, and Pseudomonadaceae families. Under special conditions, the same pyocinogenic P. aeruginosa strain can be affected by it own suspensions. These pyocinlike particles could be considered as a regulatory factor acting on the rate and size of the population growth.
The initiation and growth of bacterial spinae
Authors: Easterbrook K. B. , Alexander S. A.
Published: May 2010

Marine pseudomonad D71 (NCMB 2018) can be maintained in either the unspined or spined state depending on the salinity, pH, and temperature. Shifting bacteria from conditions restrictive for spination to those permissive for spination results in the production of spinae after a lag of less than 1 h. The percentage of spined bacteria in the population increases from 0 to nearly 100% in about one generation period (approximately 75 min). Concomitantly, the average number of spinae per bacterium increases linearly to reach a maximum in about 6 h. Spina bases are first observed at either the pole or in a central location at sites where division constriction has either occurred or is about to occur. Spinae attain full length in about 15 min and grow by addition of spinin subunits to their distal end. Inhibition studies have shown that whereas there is no significant pool of protein the mRNA is stable and is present in bacteria 30 min before spina structures are detected. Many similarities exist between spinin and outer membrane proteins and the possible significance of this is discussed.
Variability of bright, greenish-yellow fluorescent particles and aflatoxin in ground blends of Zea mays
Authors: Calvert O. H. , Lillehoj E. B. , Kwolek W. F. , Zuber M. S. , Lauver E. L.
Published: May 2010

Developing corn (Zea mays) kernels of single cross B73 × Mo17 grown near Columbia, MO, were inoculated with conidia of Aspergillus flavus or A. parasiticus. After harvest bright greenish-yellow fluorescing (BGYF) kernels were selected under ultraviolet black light (365 nm); they contained 3696 ng/g (A. parasiticus strain NRRL 3145) and 6666 ng/g (A. flavus strain UGA 5337) aflatoxins, respectively. The BGYF-free kernels were obtained from the same hybrid grown in northern Iowa. No BGYF kernels nor aflatoxins were found in 10 assays. To assess the variability in detection of BGYF particles and aflatoxin in ground corn blends, a series was developed by mixing BGYF kernels with BGYF-free kernels in various ratios. In the finely ground samples, standard deviations decreased significantly (P = 0.05) among blends for aflatoxin values in mixtures with higher levels of BGYF particles. Strain 3145 (A. parasiticus) was significantly (P = 0.01) different from strain 5337 (A. flavus) for aflatoxins concentration and the number of grams of BGYF in the blends (r > 0.99). The percent fines (passed a 40-mesh screen) in ground, 100% BGYF kernels was significantly (P = 0.01) higher for strain 3145 (A. parasiticus) inoculated samples than for strain 5337 (A. flavus) in spite of equivalent grinding procedures. This observation showed that the relationship between aflatoxin levels determined for a sample and the fraction of BGYF material in the blend was dependent on the fungal-strain source of the BGYF kernels used in the blend.
Rapid estimation of most probable number with a hand-held calculator
Authors: MacDonell M. T.
Published: May 2010

The most probable number (MPN) method of enumerating bacteria from environmental samples is widely used; however, it requires (i) that only certain numbers of tubes per dilution level be employed and (ii) a table of MPN values by which the resulting MPN codes may be evaluated. A rapid method for the estimation of MPN, regardless of the number of tubes per dilution level, applicable to unsophisticated hand-held calculators is presented.
Identification of strains isolated as total and fecal coliforms and comparison of both groups as indicators of fecal pollution in tropical climates
Authors: Lavoie Marc C.
Published: May 2010

This study was undertaken to better characterize the groups of total coliforms (TC) and fecal coliforms (FC) and to evaluate both groups as indicators of fecal contamination of drinking well water in a tropical climate (The Ivory Coast, West Africa). Isolated colonies obtained as TC or FC on membrane filters were identified using the API-20E system. From the well water samples, 58 golden-green colonies with a metallic sheen isolated on Endo medium (TC) were identified as Escherichia coli (55%), Enterobacter (26%), Klebsiella (14%), Proteus (3%), and Citrobacter (2%). Among 132 colonies isolated on Endo medium as non-TC (not showing the characteristic golden metallic sheen), 10% were identified as E. coli. The 196 blue colonies isolated on M-FC medium at 44.5 °C (FC) were identified as E. coli (66%), Klebsiella (12%), Enterobacter (10%), Citrobacter (5%), Salmonella (3%), Serratia (3%), Proteus (2%), and Yersinia (0.5%). Among 24 nonblue colonies on M-FC medium, none were identified as E. coli. Of the colonies isolated from human feces, E. coli represents 92% of the TC and 89% of the FC. Although these results are limited, they tend to confirm the greater specificity of the fecal coliform technique over that of total coliform for the detection of fecal contamination of untreated well water. From the results presented here and the observations of other workers, it is suggested that the use of FC instead of TC should be considered as the method of choice for determining drinking water pollution of untreated groundwater supplies.
Polyamine distribution in Vibrionaceae: norspermidine as a general constituent of Vibrio species
Authors: Yamamoto Shigeo , Shinoda Sumio , Kawaguchi Miho , Wakamatsu Kyomi , Makita Masami
Published: May 2010

Polyamine contents of 29 strains of the genus Vibrio, together with 5 strains of other Vibrionaceae, have been determined by a gas chromatographic method to enlarge our knowledge of the occurrence of an "unusual" polyamine, norspermidine, in the genus Vibrio. The results showed that norspermidine was widely distributed in various Vibrio species, except Vibrio fischeri and V. costicola. Besides Vibrio species, Photobacterium leiognathi and P. angustum in Vibrionaceae also contained norspermidine. When the Vibrio strains were grown in the medium supplemented with 1,3-diaminopropane, they synthesized much larger amounts of norspermidine. This ability was specific to the strains which contained norspermidine when grown in the defined medium. These findings suggested that norspermidine, as well as the ability to synthesize much larger amounts of it in the presence of 1,3-diaminopropane, may be useful generic guides to the genus Vibrio.
Hydrogenase and ribulose-1, 5-bisphosphate carboxylase activities of Alcaligenes eutrophus ATCC 17706 associated with an indigenous plasmid
Authors: Behki R. M. , Selvaraj G. , Iyer V. N.
Published: May 2010

Mutants of Alcaligenes eutrophus ATCC 17706 defective in hydrogen uptake (hydrogen oxidation) were isolated following treatment with the plasmid-curing agents Mitomycin C and Acridine orange. These mutants were devoid of hydrogenase and D-ribulose-1, 5-bisphosphate carboxylase activities, but were able to utilize formate. A single-plasmid species was identified in ATCC 17706, which was absent in all Hup− mutants, and was shown to confer hydrogen-uptake proficiency in A. eutrophus. This plasmid, pRMB1, was not self-transmissible, but was conjugative in a strain carrying a self-transmissible plasmid, RK2.
Structure of the regular surface layer of Bacillus polymyxa
Authors: Burley S. K. , Murray R. G. E.
Published: May 2010

The structure of the regular surface layer of Bacillus polymyxa has been examined to a resolution of 2.5–3.0 nm in electron micrographs of negatively stained preparations supplemented by optical-digital image enhancement. The layer is composed of morphological units, each consisting of four identical protein subunits, and has p4 symmetry with a = 10.0 nm. Within each unit cell are areas of high stain density of a limiting diameter of 2–3 nm, which are interpreted as holes penetrating the layer. A comparison is made with other tetragonal regular surface layers of spore-forming bacteria, B. sphaericus and Sporosarcina ureae, solved to 2.5-nm resolution. These layers are similar in the conformation of their protein units and in the distribution of the holes in the layer. A general scheme for the architecture of the tetragonal regular surface layers is derived.
Conditions for production of initiation protein for germination of Clostridium perfringens spores
Authors: Labbe Ronald G. , Tang Shirley S.
Published: May 2010

The amount of initiation protein (IP) produced by Clostridium perfringens was increased by approximately one-third by modification of Duncan–Strong sporulation medium to include 0.5% glucose, 2% proteose peptone, and 2% sodium phosphate. IP but no spores were produced by the wild type when grown at 46 °C and by a mutant blocked at stage 0 of sporulation. IP appears to be a vegetative cell product, perhaps an overproduced autolysin or pathogenicity factor.
Isolation and characterization of Azospirillum mutants excreting high amounts of indoleacetic acid
Authors: Hartmann A. , Singh Mahavir , Klingmüller W.
Published: May 2010

Mutants of Azospirillum brasilense Sp Cd, resistant to 5-fluorotryptophan (FT) excreted 3-indoleacetic acid (IAA), i.e., auxin, producing up to 16 μg/mL which was 30 times greater than the wild-type level. Under conditions of nitrogen fixation, the mutants excreted IAA up to 1 μg/mL, 10 times more than the wild type. However, none of the FT-resistant mutants of Azospirillum lipoferum Sp RG 20a excreted high levels of IAA. This was probably due to differences in the tryptophan and IAA biosynthetic steps between A. brasilense and A. lipoferum strains. Some of the FT-resistant mutants of A. brasilense Sp Cd showed a reduced feedback inhibition of anthranilate synthetase by tryptophan. The increased synthesis of tryptophan could explain the observed excretion of tryptophan and related metabolites. In addition, the IAA-overproducing mutants excreted other amino acids, probably owing to pleiotropic effects of deregulated tryptophan biosynthesis on amino acid metabolism. The growth patterns of some mutants excreting large amounts of IAA were almost identical to those of the wild type.
Use of 15N enrichment of soil mineralizable N as a reference for isotope dilution measurements of biologically fixed nitrogen
Authors: Chalk P. M. , Douglas L. A. , Buchanan S. A.
Published: May 2010

A preliminary investigation was conducted on an alternative approach to obtaining measurements of biologically fixed N2 by the 15N dilution technique. This approach was aimed at removing the requirement for a nonfixing reference plant. The organic N in soil was labelled by incorporating 15N-enriched plant material or by immobilizing 15N-enriched NH4+-N. A nonnodulating isoline of soybean (cv. Lee) was grown on two labelled soils in pots in a growth room, and the 15N enrichment of the plants was determined after 16 weeks of growth. The isotopic composition of inorganic N released during incubation of the labelled soils under controlled conditions in the growth room and laboratory was also determined. Close agreement was found between the 15N enrichments of plant material and nitrogen mineralized in unplanted pots maintained in the growth room. These results suggest that for plants grown in pot culture the proportion of N derived from fixation could be determined from the dilution of 15N in the plant relative to the 15N enrichment of the N mineralized. Laboratory studies demonstrated that the 15N enrichment of nitrogen mineralized decreased with time, suggesting that the application of this approach to field assessment of N2 fixation would require uniform labelling of the soil organic nitrogen.
Fractionation and identification of cellulases and other extracellular enzymes produced by Sporotrichum (Chrysosporium) thermophile during growth on cellulose or cellobiose
Authors: Canevascini G. , Fracheboud D. , Meier H.
Published: May 2010

The extracellular enzyme proteins secreted by Sporotrichum (Chrysosporium) thermophile, ATCC 42 464, upon growth on cellulose or cellobiose, were separated by polyacrylamide gel electrophoresis and electrofocusing into different fractions which were then analyzed with respect to their enzymatic character to identify the cellulolytic enzymes. A positive reaction against carboxymethylcellulose azure (CMC azure) was taken as evidence for an endo-acting cellulase, whereas the criterion for the presence of an exo-cellulase was a negative reaction with CMC azure and a concomitant increase in reducing power upon action of any kind of cellulose. With this procedure, four main cellulolytic enzymes were detected: three endo-cellulases, named endo-cellulases I, II, and III (with corresponding isoelectric points 5.1, 4.2, 5.7), and an exo-cellulase (isoelectric point 4.7). With respect to their enzymatic action on amorphous cellulose, endo-cellulases I and III were isofunctional, releasing cellobiose and cellodextrins as hydrolytic products, whereas endo-cellulase II was found to produce additionally some glucose. Endo-cellulases I and III were also able to attack native (crystalline) cellulose like filter paper or Avicel, but endo-cellulase II could not and thus behaved as a true carboxymethylcellulase. The rate of formation of endo-cellulase I during growth was distinctly superior from that of the other cellulases so that the proportion of the activity due to endo-cellulase. I compared with that due to the others constantly increased during the culture.
The significance of 3-ketolactose in the lactose catabolism by Agrobacterium
Authors: Janssens D. , Kersters K. , Ley J. De
Published: May 2010

The metabolic implications of both the production and the catabolism of 3-ketolactose during growth of 3-ketolactose-positive agrobacteria on lactose have been investigated. It was concluded that 3-ketolactose is not a necessary intermediate for the transport reaction of lactose to the cytoplasm and is on a sidetrack from the main catabolic route of lactose. Furthermore, in media with 2% lactose cell yield of 3-ketolactose-positive, but not of 3-ketolactose-negative, strains was improved by the presence of 10−5 M Mn2+. This increase was attributed to a decreased synthesis of D-aldohexoside:cytochrome c oxidoreductase, whereby the conversion of lactose to 3-ketolactose was slowed down and lactose remained available for a longer time for exponential growth.
Effect of hydrogen and oxygen on uptake-hydrogenase activity in nitrogen-fixing and ammonium-grown Azospirillum brasilense
Authors: Tibelius Karl H. , Knowles Roger
Published: May 2010

Hydrogen uptake by Azospirillum brasilense was studied in N2-fixing and NH4Cl-grown batch cultures. The Km for H2 of uptake hydrogenase (O2-dependent H3H uptake) in whole cells was 9 µM. In N2-flxing or NH4Cl-grown cultures hydrogenase activity reached its maximum in late log phase, followed by a rapid decline in stationary phase. In cultures sparged with H2, hydrogenase activity was markedly prolonged. Rates of O2-dependent H3H uptake and H2 uptake measured by gas chromatography were very similar. Hydrogenase derepression required microaerobic conditions, was independent of nitrogenase derepression, did not require exogenous H2, and may be enhanced by electron-donor limitation. Air caused irreversible inhibition of hydrogenase activity. In N-free cultures, theO2 optima for H2 uptake, ranging from 0.5 to 1.25% O2 depending on the phase of growth, were significantly higher than those for nitrogenase activity (C2H2 reduction), 0.15 to 0.35%, suggesting that H2 uptake may have a limited ability to aid in the protection of nitrogenase against inactivation by O2.
A note on the identity and properties of the spoilage microflora of chub-packed luncheon meat stored at ambient temperature
Authors: Bell R. G. , Lacy Karen M. de
Published: May 2010

The principal spoilage bacteria isolated from chub-packed luncheon meat stored at 25 °C have been identified as strains of Bacillus licheniformis and Streptococcus faecium. Bacillus licheniformis alone is responsible for those degradative changes (surface softening and discolouration, gas production and eventual product liquefaction) regarded as overt product spoilage. Streptococcus faecium metabolizes carbohydrate homofermentatively, and the resultant accumulation of lactic acid causes souring of the luncheon meat.
Protein and lipid methylation by methionine and S-adenosylmethionine in Myxococcus xanthus
Authors: Panasenko Sharon M.
Published: May 2010

Methylation of lipids and proteins has been examined in Myxococcus xanthus using radioactive methionine and S-adenosylmethionine as methyl donors. S-adenosylmethionine is shown to be taken up by these cells and utilized directly. This permits detection of methylation in the presence of protein synthesis. Patterns of methylation obtained using methionine and S-adenosylmethionine during vegetative growth are compared by polyacrylamide gel electrophoresis, and inhibitors of protein synthesis and S-adenosylmethionine synthesis are examined for their effects on methylation. The ability to investigate methylation using exogenous S-adenosylmethionine will be advantageous in studying the role of methylation under conditions of growth and development where ongoing protein synthesis is required.
Cyclic AMP is not detectable in Clostridium perfringens
Authors: Setlow Peter , Sacks L. E.
Published: May 2010

Cyclic AMP was not detected (<5 × 10−9 M intracellular concentration) at any stage of growth or sporulation of two strains of Clostridium perfringens grown with or without methylxanthines. Only Bacillus and Lactobacillus, genera belonging to the same phylogenetic cluster, have previously exhibited undetectable levels of cyclic AMP.
Aspect morphologique et composition chimique de Skeletonema costatum(Bacillariophyceae) croissant en milieu nutritif naturel à l'aide d'un système de culture à fibres dialysantes
Authors: Marsot Pierre , Leclerc Marc , Fournier Réal
Published: May 2010

The growth of Skeletonema costatum, under natural nutriment conditions, was studied using a bulk culture fiber dialyzing apparatus. The diatom displayed normal development of chain length (average cell number per chain) which coincided with the culture growth stages; that is, the cell number per colony increased during the active division period and decreased thereafter with the beginning of the prestationary phase. This morphological behaviour showed that the alga cells were not affected by such physical shocks as collision or tension occurring during repeated cell transfers from growth chambers to the dialyzing apparatus or at the time of their passage through the fiber fascicles. Measured at different growth stages, the cell contents in carbon, nitrogen, and chlorophyll confirmed the above results and showed for S. costatum a biological productivity comparable with that obtained in smaller dialyzing containers (dialyzing bags). Through a comparison between the dialyzing culture and a static culture grown in an enriched medium, certain characteristics were determined.[Translated by the journal]
The relationship between three potential pathogens and pollution indicator organisms in Nova Scotian coastal waters
Authors: Robertson W. J. , Tobin R. S.
Published: May 2010

Fifteen stations, in two estuaries, along the Northumberland Strait of Nova Scotia were examined between June and September 1981 for a relationship between the concentrations of commonly monitored fecal indicator bacteria and the potential pathogens Candida albicans, Pseudomonas aeruginosa, and Vibrio parahaemolyticus. Increased densities of these three organisms were usually associated with high densities of indicator bacteria. Whereas C. albicans and P. aeruginosa occur in human fecal wastes, V. parahaemolyticus is indigenous to the marine environment and positively responds to elevated nutrient levels in sewage. There is also some evidence that these bacteria survive as long or longer in marine waters than the common indicator bacteria. While membrane-filtration techniques for the enumeration of C. albicans and P. aeruginosa proved satisfactory, a V. parahaemolyticus membrane-filtration method lacked specificity and was supplemented by a most-probable-number method. In marine recreational and shellfish waters, these three organisms could complement fecal coliforms and fecal streptococci as indicators of human fecal contamination.
Mouse immune response to meningococcal antigens
Authors: Micusan V. V. , Bisaillon J. G. , Sparkes B. G. , Desrosiers M. , McSween G. , Dupuy J. M.
Published: May 2010

The mouse immune response against Neisseria meningitidis was studied by using an extract from group Y (Slaterus) known to contain protein antigens common to other meningococci. By using a solid-phase radioimmunoassay, high titers of specific IgM and IgG class antibodies were measured which lasted over 2 months after immunization. These antibodies cross-reacted with similar extracts from other meningococci groups. Bactericidal antibodies directed against protein antigens were also elicited after immunization and they belonged to IgM, IgG2a, and IgG2b isotypes. Cellular immunity, expressed as delayed type hypersensitivity under the conditions tested, could be detected neither in homologous nor heterologous reactions.
Effect of rat polymorphonuclear leukocyte granule components on the growth and survival of Pseudomonas aeruginosa and Salmonella typhimurium
Authors: Modrzakowski M. C. , Dosch-Meier D. , Hodinka R. L.
Published: May 2010

Granule contents from rat polymorphonuclear neutrophils were prepared by extraction with 0.2 M acetate buffer (pH 4.0), dialyzed against phosphate-buffered saline (pH 7.0), and tested for bactericidal activity against selected target bacteria. Salmonella typhimurium LT-2 and a series of progressively rough lipopolysaccharide outer membrane mutants derived from it were used to monitor antimicrobial activity. Although an antimicrobial potential was present in rat granule contents for S. typhimurium, the growth of Pseudomonas aeruginosa PAO-1 in antimicrobial assay mixtures containing rat granule contents was substantially enhanced over control values. The growth enhancement property of the granule protein was heat resistant and promoted increased oxygen consumption by whole cells.
Acid and alkaline phosphatases of Capnocytophaga species. III. The relationship of the enzymes to the cell wall
Authors: Poirier Thomas P. , Holt Stanley C.
Published: May 2010

Acid (AcP) and alkaline phosphatase (AlP) were localized by physicobiochemical techniques. Greater than 53% of the phosphatases were detected, following sonication, in a low speed centrifugation pellet while osmotically shocked and spheroplasted Capnocytophaga species released only 9–28% and 11–43% of the cellular phosphatases, respectively. French pressure cell disruption was more effective in releasing the phosphatases. Cell fragments were separated into cell wall, cytoplasmic membrane, and soluble fractions as determined by marker enzyme, chemical composition, transmission electron microscopy, sodium dodecyl sulphate – polyacrylamide gel electrophoresis (SDS–PAGE) protein analysis, and gel diffusion. AcP and AlP was partitioned between the isolated cell wall (31–46%) and soluble material (33–61%), with greater than 60% of the phosphatases remaining with the cell wall following Triton X-100 treatment. The amount of phosphatase at the surface of intact C. ochracea was quantitated by specific 125I-protein labelling.
Stabilizing effect of acetate salts and in digestors receiving high levels of glucose
Authors: Robbins J. E. , Armold M. T. , Weiel J. E. , Runquist E. A.
Published: May 2010

Anaerobic digestors were fed daily with dairy cattle manure (5% total solids) augmented with 0–20 mM glucose and were monitored daily for gas volume and composition and volatile acid content. Propionate accumulated in digestors that were fed glucose at initial digestor concentrations of 10 mM or more. Digestors that received 14–20 mM glucose failed, but identical digestors that received 20 mM glucose plus 10 mM acetate or [Formula: see text] did not fail. The sparing effect of [Formula: see text] was primarily buffering and the similar behavior of digestors that received acetate suggest that acetate metabolism perhaps provided additional [Formula: see text] for buffering. Analyses of H2 and volatile acid concentrations during a 6–8-h period following feeding in digestors fed glucose or glucose plus acetate showed that propionate and H2 accumulated simultaneously and that H2 concentrations were 3 μM or less. Monitoring 13C-labeled glucose metabolism via 13C nuclear magnetic resonance indicated that glucose was primarily converted to lactate and that the major product from lactate was propionate in both glucose and glucose plus acetate fermentations.
Effects of NaCl on the uptake of α-[14C]aminoisobutyric acid by the halotolerant bacterium Halomonas elongata
Authors: Martin E. L. , Duryea-Rice T. , Vreeland R. H. , Hilsabeck L. , Davis C.
Published: May 2010

The α-aminoisobutyric acid (AIB) transport system of the halotolerant bacterium, Halomonas elongata, was examined. Cells were grown in L-alanine defined medium with 0.05, 0.375, 1.37, 2.5, or 3.4 M NaCl. Each group of cells was resuspended in buffered salts with different NaCl concentrations (0.05, 0.375, 1.37, 2.5, and 3.4 M) and the uptake of α-[14C]AIB was measured. Optimum AIB uptake occurred in the 0.375 M NaCl solution for the lower salt grown cells and the 1.37 M NaCl solution for the higher salt grown cells. When cells were grown in the higher salt media and suspended in hypoosmotic solutions, appreciable AIB uptake occurred; but for cells grown in lower salt media and suspended in hyperosmotic solutions, the uptake was dramatically reduced. This effect was mainly attributed to cell plasmolysis which in turn resulted in some cell death. The AIB uptake was Na+ specific and this analogue was not metabolized after being transported into the cells. An amino acid competition study gave a pattern similar to that of a marine bacterium.
Exudation from 14C-labeled fungal propagules in the presence of specific microorganisms
Authors: Arora D. K. , Filonow A. B. , Lockwood J. L.
Published: May 2010

Exudation from 14C-labeled conidia of Cochliobolus victoriae and sclerotia of Macrophomina phaseolina was greater in the presence of cells of five bacterial species or propagules of four fungal species in phosphate buffer or in sterilized soil than in buffer without other microorganisms. In most instances, the increased exudation was statistically significant at P = 0.05. High population densities of bacterial cells or fungal propagules induced greater exudation than lower densities. 14C exudation from C. victoriae conidia in the presence of specific microorganisms was 1.5–9.9% of total label in buffer and 1.0–3.8% on soil; exudation from M. phaseolina sclerotia was 1.4–3.2% of total label in buffer and 1.3–3.2% on soil. All microorganisms tested, except Actinoplanes utahensis and M. phaseolina, suppressed germination of conidia of C. victoriae and sclerotia of M. phaseolina in vitro. Exudation of 14C-labeled compounds was inversely correlated with germination of C. victoriae conidia (r = −0.72) and M. phaseolina sclerotia (r = −0.74). The results indicate that specific microorganisms can enhance exudation from fungal propagules and that the enhanced exudation may be related to the imposition of mycostasis.
An analysis of the metabolism and cell wall composition of Candida albicans during germ-tube formation
Authors: Sullivan Patrick A. , Yin Chiew Yoke , Molloy Christopher , Templeton Matthew D. , Shepherd Maxwell G.
Published: May 2010

The uptake of nutrients (glucose, glutamine, and N-acetylglucosamine), the intracellular concentrations of metabolites (glucose-6-phosphate, cyclic AMP, amino acids, trehalose, and glycogen) and cell wall composition were studied in Candida albicans. These analyses were carried out with exponential-phase, stationary-phase, and starved yeast cells, and during germ-tube formation. Germ tubes formed during a 3-h incubation of starved yeast cells (0.8 × 108 cells/mL) at 37 °C during which time the nutrients glucose plus glutamine or N-acetylglucosamine (2.5 mM of each) were completely utilized. Control incubations with these nutrients at 28 °C did not form germ tubes. Uptake of N-acetylglucosamine and glutamine was inhibited by cycloheximide which suggests that de novo protein synthesis was required for the induction of these uptake systems. The glucose-6-phosphate content varied from 0.4 nmol/mg dry weight for starved cells to 2–3 nmol/mg dry weight for growing yeast cells and germ tube forming cells. Trehalose content varied from 85 nmol/mg dry weight (growing yeast cells and germ tube forming cells) to 165 nmol/mg weight (stationary-phase cells). The glycogen content decreased during germ-tube formation (from 800 to 600 nmol glucose equivalent/mg dry weight) but increased (to 1000 nmol glucose equivalent/mg dry weight) in the control incubation of yeast cells. Cyclic AMP remained constant throughout germ-tube formation at 4–6 pmol/mg dry weight. The total amino acid pool was similar in exponential, starved, and germ tube forming cells but there were changes in the amounts of individual amino acids. The overall cell wall composition of yeast cells and germ tube forming cells were similar: lipid (2%, w/w); protein (3–6%), and carbohydrate (77–85%). The total carbohydrates were accounted for as the following fractions: alkali-soluble glucan (3–8%), mannan (20–23%), acid-soluble glucan (24–27%), and acid-insoluble glucan (18–26%). The relative amounts of the alkali-soluble and insoluble glucan changed during starvation of yeast cells, reinitiation of yeast-phase growth, and germ-tube formation. Analysis of the insoluble glucan fraction from cells labelled with [14C]glucose during germ-tube formation showed that the chitin content of the cell wall increased from 0.6% to 2.7% (w/w).
Reproduction of Cephalosporium eichhorniae as spheroplasts
Authors: Charoensiri Kachorn , Gregory Kenneth F.
Published: May 2010

About 0.7% of the conidia and 0.3% of the enzymatically produced spheroplasts of Cephalosporium eichhorniae 152 (ATCC 38255) grew as colonies of spheroplasts on agar medium containing 0.8 M glucose. Both primary (enzymatically produced) and cultured spheroplasts were osmotically sensitive. Cultured spheroplasts contained from 0 to 10 nuclei each. They were larger than primary spheroplasts with the most frequent size classes having volumes of 49.6 and 6.2 μm3, respectively. Cultured spheroplasts gave high yields of colonies (31%) in medium with 0.6 M KCl, while neither spores nor primary spheroplasts grew on this medium. Cultured spheroplasts grew slowly in gently shaken liquid media, containing various osmotic stabilizers, to produce dense growth (3.9 × 107 spheroplasts/mL) in 8 days.
The epidemic spread of Salmonella typhimurium phage type 10 in Canada (1970–1979)
Authors: Khakhria R. , Bezanson G. , Duck D. , Lior H.
Published: May 2010

The frequency of Salmonella typhimurium phage type 10 across Canada was monitored during the period 1970–1979. Phage type 10 isolations increased from 1.2% in 1970 to 68.8% in 1979 among isolates from human sources and from 1.5 to 30.6% in isolates from nonhuman sources. Examination of food-poisoning outbreaks and a study of the animal–host associations of phage type 10 revealed that contaminated poultry products appear to be the most common sources of human infections. The majority (89.3%) of S. typhimurium phage type 10 strains were sensitive to antibiotics. Of the resistant strains, 73.3% were resistant to single antibiotics and 26.7% were multiresistant. Thirty-three different patterns of antibiotic resistance were observed. A number of the resistance determinants were transferable by conjugation and the R plasmids were found to belong to the incompatibility groups HI1, FII, N, Iα, and C.
Immunomodulating activity of meningococcal antigens
Authors: Sparkes Brian G.
Published: May 2010

A preparation of meningococcal antigens (MA) extracted in CaCl2, and containing mostly outer membrane proteins, was strongly mitogenic for murine B lymphocytes. Given to mice in vitro, MA markedly impaired subsequent in vivo T-cell responses of splenocytes. Suppression of normal T splenocytes in vitro occurred with both adherent (Ad) and nonadherent (NA) splenocytes from MA-sensitized mice. B cells were much less affected by the suppression induced by MA, and only Ad cells could convey in vitro the low level impairment of B-cell proliferation. Strong T-cell suppression associated with a B-cell mitogen is also produced by bacillus Calmette-Guérin (BCG) and Corynebacterium parvum. The possible role of these phenomena in meningococcal disease is discussed.
Examination of immobilized fungal cells by phase-contrast and scanning electron microscopy
Authors: Deo Y. M. , Costerton J. W. , Gaucher G. M.
Published: May 2010

Conidia of Penicillium urticae were immobilized in kappa-carrageenan beads and then shaken, in a growth-supporting medium to yield an in situ grown population of mycelia. The physical stability of these beads and the degree of mycelial growth inside the beads were significantly affected by the concentrations of κ-carrageenan and locust bean gum (LBG) in the bead matrix and by the porous or nonporous nature of the interior. Thus 16-h-old porous and nonporous beads, prepared from 1.25% κ-carrageenan, 0.5% LBG, and conidia, possessed a very dense mycelial mass at the surface. Only the porous beads possessed a moderately dense mycelial mass at the centre. The conidia at the centre of nonporous beads either failed to germinate or formed very small germ tubes. When washed, 36-h-oid porous beads were repeatedly (i.e., 48 h) transferred into nitrogen-free medium, the density of mycelia at the centre increased to equal that at the surface after three transfers or 8 days. Mycelia at the surface exhibited signs of physical damage, while those in the centre did not. The addition of 100 μg/mL of cycloheximide to these replacement cultures was reflected by the distortion of interior mycelia.
Interaction in vitro entre l'association ampicilline–colistine et Escherichia coli resistant à l'ampicilline
Authors: Coste M. , Escoula L.
Published: May 2010

In this work, the authors studied in vitro potential interactions between bacteria and antibiotics. Colistin and ampicillin were introduced to ampicillin-resistant Escherichia coli and ampicillin activity was measured. Two layers of agar media were used. The lower layer contained E. coli and colistin. The superficial layer was sown with indicating bacteria (ampicillin-sensitive Proteus mirabilis). Ampicillin activity was evaluated on the upper layer with impregnated disks. By this technique, it was ascertained that ampicillin degradation increased with colistin concentration. In this case, colistin may favour interactions of intracellular beta-lactamases on ampicillin.
Subunit composition of goblet-shaped particles from the cell wall of Flexibacter polymorphus
Authors: Ridgway H. F. , Lewin R. A.
Published: May 2010

Submicroscopic goblet-shaped particles (goblets) were released from the cell envelope of the marine gliding bacterium Flexibacter polymorphus when treated with the nonionic detergent Triton X-100 followed by sonication. The goblets were purified by cesium chloride density gradient centrifugation and exhibited an equilibrium buoyant density of 1.30 g/mL at 23 °C. They were composed of protein and a small amount of carbohydrate (approximately 3.4% by weight). Aqueous suspensions exhibited an absorption maximum in the ultraviolet at a wavelength of 276 nm and a smaller shoulder at 281 nm. Phospholipids were not detected in purified preparations of goblets, though they are known to be prominent constituents of the intact membranes of this microbe. Polyacrylamide gel electrophoresis of goblets solubilized in sodium dodecyl sulfate and 2-mercaptoethanol indicated four major polypeptide components ranging in molecular weight from 13 000 to 80 000. This number of different protein subunits corroborates earlier ultrastructural observations indicating a multisubunit composition.