bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure of chitin in the cell walls of newly formed and mature conidia of Fusarium sulphureum
Authors: Schneider E. F. , Seaman W. L.
Published: May 2010

Samples of 7-day-old septate conidia (mature conidia) and newly released aseptate ones (immature conidia) of Fusarium sulphureum were hydrolyzed successively in KOH, acetic acid – H2O2, and H2SO4. The cell wall residue of the mature conidia remained intact throughout the hydrolysis but that of immature conidia dissolved in the H2SO4. Thus, the immature conidial cell wall is substantially different from that of mature conidial cells or growing hyphae and the cell wall undergoes a structural transformation following conidium release from the conidiogenous cell. X-ray diffraction analyses of the wall residues following KOH and acetic acid – H2O2 hydrolysis showed that the mature conidial wall residue had a crystalline chitin component, while the residue of the immature conidial wall was more amorphous and had smaller crystals. An X-ray diffraction pattern of the dissolved immature conidial wall that was recovered from the H2SO4 hydrolysate showed that it contained crystalline chitin.Infrared spectroscopic analysis of the mature conidial cell wall residue showed absorption bands due to inter- and intra-molecular hydrogen bonding and for hydrogen stretching associated with crystalline chitin. Such bands were lacking in the immature cell wall analogue.
Effects of chromium and manganese on Thiobacillus ferrooxidans
Authors: Wong Chen , Silver Marvin , Kushner Donn J.
Published: May 2010

Growth of Thiobacillus ferrooxidans at pH 2.5 is inhibited by concentrations of Cr2(SO4)3 greater than 1.5 × 10−2 M or by concentrations of MnSO4 greater than 0.6 M. Ferrous iron oxidation is less sensitive than growth to the inhibitory effects of Cr2(SO4)3 and MnSO4, and these inhibitions are greater at higher pH values. The inhibition of growth and iron oxidation by MnSO4 appears to be due only to general osmotic effects rather than to the specific ionic concentration. Growth of Escherichia coli is inhibited by 10−4 M K2Cr2O7 or by 2.4 × 10−2 M MnSO4. Although T. ferrooxidans causes the solubilization of chromium from a chromite concentrate to a maximum of 140 mg/L, this action may not be sufficient for commercial exploitation but may be sufficient for environmental concern.
Phylloplane bacteria in a pine forest
Authors: Yoshimura Fumihiko
Published: May 2010

Fluctuation of bacterial population occurring in the three growth stages (young, old, and decaying) of the leaves of Pinus densiflora and in the air of the same pine forest was examined using the dilution plate method. The total count of bacteria isolates from the phylloplanes of pine was not high but seasonal fluctuations, particularly with respect to composition, were marked bacterial populations. Approximately 70% of the total isolates collected in 5 years was found to belong to the following four groups: pink chromogens, Bacillus, Flavobacterium, and coryneform bacteria. Among them, pink chromogens occurred abundantly on the living phylloplanes of P. densiflora during summer. Bacillus was isolated from the various sources all year round. Coryneform bacteria occurred in the air of the pine forest throughout the year. Flavobacterium was observed in all sources, but not in high number. Staphylococcus and Micrococcus were not detected on the phylloplanes in spite of their abundance in the air.
Inorganic phosphate solubilization by rhizosphere bacteria in a Zostera marina community
Authors: Craven Pamela A. , Hayasaka Steven S.
Published: May 2010

Actively growing Zostera marina plants had a greater rhizosphere inorganic phosphate solubilizing potential than dormant plants. Rhizosphere bacteria that were capable of calcium phosphate solubilization were obligate aerobes and numbered approximately 4 × 108 colony-forming units/g dry weight root. Bacterial isolates solubilized calcium phosphate when cultured with glucose as the sole carbon and energy source but not when cultured with amino acids. Both calcium phosphate (hydroxyapatite) and glucose were found in sea grass bed sediment. Acetic acid was also detected from roots plus clinging sediment, from sediment, and from cultured bacterial isolates in a glucose-supplemented medium. The minimum concentration of acetic acid that showed detectable solubilization of calcium phosphate was 10−5 M. It is suggested that acetic acid, a product of glucose metabolism in the rhizosphere flora, is responsible for phosphate solubilization in the environment.
The protective mechanism of action of amines in diphtheria toxin treated Vero cells
Authors: Dorland Rebecca B.
Published: May 2010

The mechanisms by which a number of alkylamines and ethylenediamine derivatives protect Vero cells from diphtheria toxin were studied. The protective alkylamines and ethylenediamine compounds blocked the cellular degradation of diphtheria toxin, but did not prevent bulk toxin uptake. Specific antibody neutralized the inhibitory effects of toxin on protein synthesis in amine-treated cells when added at 37 °C, but was ineffective when added at 4 °C. Analogous results were obtained when inositol hexaphosphate was used in the place of specific antibody. Both experiments suggested that, in the presence of the amine compounds studied, diphtheria toxin is sequestered intracellularly and is recycled to the surface for antibody or inositol hexaphosphate neutralization. Finally, it was shown that the protective amines markedly increased the intralysosomal pH of Vero cells and that when the pH of the culture medium was lowered to 4.5, the amine-mediated protective effect was bypassed. In general, the results suggest that the amines exert their protective effect at the level of some acidic intracellular vesicle population, possibly the lysosomes, and thus may indicate a crucial role for the lysosomes in the generation of cytotoxicity.
Cellular and extracellular lipids of Acinetobacter lwoffi during growth on hexadecane
Authors: Vachon Vincent , McGarrity James T. , Breuil Colette , Armstrong John B. , Kushner Donn J.
Published: May 2010

The cellular and extracellular lipid compositions of Acinetobacter lwoffi cultures were examined during diauxic growth on ethanol and hexadecane. Growth at the expense of ethanol resulted in proportionate increases in the main lipid components of A. lwoffi. After a prolonged lag phase following depletion of ethanol, growth at the expense of hexadecane resulted in an increase in phospholipids, but little change in the amounts of the other lipid species. The phospholipids were acylated, during growth on hexadecane, with larger proportions of palmitate and palmitoleate and smaller proportions of the 18-carbon fatty acids.Due to tenacious binding of cells to the hexadecane remaining in the growth medium, we were unable to obtain completely cell-free extracellular supernatants. Consequently, the levels of extracellular lipids were estimated as the difference between the actual amount of lipid measured in the supernatant and the amount theoretically associated with the bound cells. Using this approach, the extracellular lipids were found, during diauxie, to be present at levels similar to those formed in cultures grown on ethanol, in the absence of hydrocarbon. The lipid composition of the cell pellets and culture supernatants were relatively similar; hence, a disproportionate accumulation of one or more lipid species in the extracellular medium was not apparent.
Interaction of pseudomonas exoproducts with phagocytic cells
Authors: Weber Bruce , Nickol Michele M. , Jagger Kathleen S. , Saelinger Catharine B.
Published: May 2010

Polymorphonuclear leukocytes play the major role in host defense against infections with Pseudomonas aeruginosa; however, mononuclear cells also may contribute to defense against pulmonary infections with P. aeruginosa. Therefore, we examined the effects of three extracellular products of P. aeruginosa, exotoxin A, alkaline protease, and elastase, on the function of phagocytic cells. Phagocytosis or killing, protein synthesis, and membrane integrity were used as assays of cellular function. Pseudomonas toxin readily inhibited protein synthesis in mouse peritoneal macrophages; in contrast, proteolytic enzymes did not alter protein synthesis, but transiently decreased the sensitivity of macrophages to toxin. High levels of toxin reduced protein synthesis in human peripheral polymorphonuclear leukocytes but did not alter the ability of these cells to kill P. aeruginosa. Elastase and alkaline protease did not cause release of marker enzymes and did not directly inhibit the bactericidal activity of polymorphonuclear leukocytes; killing was reduced due to inactivation of complement components. In conclusion, these potential virulence products do not modify phagocyte function directly and thus do not directly interfere with host response in pseudomonas infections.
Evidence of microbial succession on decaying leaf litter in an arctic lake
Authors: Federle Thomas W. , Vestal J. Robie
Published: May 2010

Microbial colonization and its relation to the decomposition of sedge (Carex) leaf litter were studied in the littoral area of Toolik Lake, Alaska. Colonization was assessed using scanning electron microscopy and by measuring the concentration of ATP associated with the litter. Litter lost approximately 20% of its dry weight and 60% of its phosphorus by leaching during the first 4 days of exposure to lake water. Microbial activity was responsible for any additional decomposition. Microorganisms were first observed on the litter surface on the 3rd day of incubation in the lake, when isolated bacterialike forms and microbial filament were present, but ATP was not yet detected. This initial appearance of microbes was followed by a dramatic rise in ATP concentration and a rapid proliferation of microbial forms, especially large filaments. Associated with this rapid colonization was a steep decline in nitrogen content, a twofold increase in protein content, and the appearance of microbially mediated weight loss of the litter. By day 13, microbial colonization declined by 50% and remained stabilized at this lower level for the duration of the study. This decline coincided with the demise of the large filamentous forms, a decrease in the protein content of the litter, and slower but continued decrease in the nitrogen content of the litter. As time progressed, the microbial community became increasingly characterized first by the presence of bacterialike forms enmeshed in slime and later by large numbers of penna*** diatoms. These findings show that decomposition is dependent on the development and succession of the microbial community on the litter.
β-D-Xylanases of Bacillus circulans WL-12
Authors: Esteban R. , Villanueva J. R. , Villa T. G.
Published: May 2010

Bacillus circulans WL-12 secretes two endo-β-D-xylanases (A and B, respectively) (EC 3.2.1.8.) and one β-D-xylosidase (EC 3.2.1.37) when cultured in liquid media with xylan as the sole carbon source. Xylanases A and B have been partially characterized with respect to their main physicochemical parameters and β-D-xylosidase to a lesser extent on account of its low stability. Both endo-β-D-xylanase A and β-D-xylosidase were adsorbed on DEAE-Biogel A, had similar molecular weights (approximately 85 000), and had optimum pH values of 5.5–7, but exhibited different isoelectric points (4.5 for β-D-xylanase A and 4.7 for β-D-xylosidase) and different mobilities in polyacrylamide gel electrophoresis. The apparent Michaelis constant for β-D-xylanase A was 8 mg∙mL−1 and the hydrolysis products produced were xylose, xylobiose, xylotriose, and xylotetraose.The second endo-β-D-xylanase (β-D-xylanase B) bound to CM-Biogel A and exhibited a molecular weight of approximately 15 000 and an optimum pH value in the range of 5.5–7. The isoelectric point was 9.1 and the apparent Michaelis constant was 4 mg∙mL−1. The hydrolysis products produced by this enzyme were xylobiose, xylotriose, and xylotetraose, but never xylose. In polyacrylamide gel electrophoresis at pH 8 the enzyme moved towards the negative electrode.
Death of Pseudomonas aeruginosa in soil
Authors: Zechman James M. , Casida Jr. L. E.
Published: May 2010

When incubated in natural (nonsterilized) soil, Pseudomonas aeruginosa died initially at a rate which approximated the rate for starvation of a pure culture in buffer. Predation by other soil microbes or phage did not appear to be involved, and pycocyanin either was not produced or was ineffective. The initial rate of death was followed by a second, considerably slower rate. Cells initially added in low numbers to soil also underwent biphasic death as above. Slow drying of the soil caused a period of rapid death of P. aeruginosa, but this then slowed to give residual numbers and a death rate similar to the second death rate noted for soil not allowed to dry. The cells in the dry soil had not changed genetically to a desiccation-resistant form. Pseudomonas aeruginosa died out completely in a relatively short time when the soil was first quickly dried to a water content similar to that obtained initially through slow drying and then further allowed to dry slowly. These observations appear to point to a dormant form, in some ways resembling a cyst, for P. aeruginosa in soil.
Effect of purine derivatives, papaverine hydrochloride, and imidazole on enterotoxin formation by Clostridium perfringens type A
Authors: Craven S. E. , Blankenship L. C.
Published: May 2010

The percentage sporulation and enterotoxin specific activity were improved for all of five Clostridium perfringens strains, and numbers of heat-resistant spores were improved for four of five strains by replacing proteose peptone with peptone in Duncan–Strong (DS) medium. When raffinose replaced starch in DS, peptone was superior to proteose peptone in increasing percentage sporulation, numbers of heat-resistant spores, and enterotoxin formation for four of five strains. Enterotoxin levels for a strain varied when different lots of the same peptone were used. Additional experiments were conducted with three C. perfringens strains grown in DS medium with peptone. Enterotoxin specific activity was increased for three strains by adding papaverine (hydrochloride crystalline), for two strains by adding each of caffeine and 3-isobutyl-1-methylxanthine, for one strain by adding each of theophylline, 6-mercaptopurine, and 2-amino-6-mercaptopurine, and for none of the strains by adding imidazole. When enterotoxin formation was improved for a strain by one of the compounds, percentage sporulation increased, but growth decreased. Effective compounds also increased numbers of heat-resistant spores for strains H6 and R42, but slightly or not at all for strain E13. The action of these compounds was concentration dependent, with the optimal concentration differing between compounds and between strains grown in the presence of the same compound.
Infection process and sloughing off of rhizobial outer membrane in effective nodules of lima bean
Authors: Bal Arya K. , Wong Peter P.
Published: May 2010

In addition to infection via root hairs, infection threads originating in epidermal cells after colonization of epidermis have been clearly demonstrated in lima beans infected with Rhizobium sp. 127E15, and this double mode of infection possibly accounts for profuse nodulation of the roots. Sloughing off of the outer membrane (cell wall) was detected after release of rhizobia during bacteroid differentiation in effective nodules.
Transport of 2-deoxy-D-glucose by isolated protoplasts of the yeast, Kluyveromyces lactis
Authors: Royt Paulette W. , Tombes Averett S.
Published: May 2010

Protoplasts of succinate- and glucose-grown Kluyveromyces lactis were generated by incubating cells with β-mercaptoethanol and β-glucuronidase in the presence of MgSO4 as osmotic stabilizer. Transport of 2-deoxyglucose by the protoplasts was comparable with that of the walled cells. Only protoplasts of succinate-grown cells exhibited a lag in glucose utilization. Removal of the wall by this technique does not result in loss of the inducible component of the glucose carrier via degradation or release.
The role of some membrane dehydrogenases in Pseudomonas fluorescens
Authors: Lynch William H.
Published: May 2010

The membrane-associated oxidative enzymes glucose, gluconate, and malate dehydrogenases were examined in psychrotrophic Pseudomonas fluorescens. The function and activity of these enzymes was determined by measuring extracellular product formation by washed cell suspensions. Membrane dehydrogenase activities and corresponding transport activities for the substrates glucose, gluconate, and malate were compared in batch cultures grown with these substrates at 30 and 5 °C. These activities correlated with the production or lack of extracellular oxidation products. In chemostat cultures grown at 30 and 5 °C, the membrane enzymes and production of their extracellular oxidation products appeared to be regulated by the available carbon concentration. The enzymes were induced and high concentrations of extracellular oxidation products were produced under conditions of nitrogen limitation (carbon excess) but not carbon limitation. The lower affinities of the three membrane enzymes for their respective substrates, when compared with the transport systems utilizing the same substrates, correlated with the observed major function of these enzymes in carbon-excess environments. The primary role of the membrane-associated oxidative enzymes, in carbon dissimilation by this psychrotrophic microorganism at low temperatures in carbon-excess environments, was strongly implicated.
Bacteriophages of Halobacterium halobium: isolation from fermented fish sauce and primary characterization
Authors: Pauling Crellin
Published: May 2010

Bacteriophages infecting extremely halophilic bacteria of the genus Halobacterium have been isolated from fermented anchovy sauce. Two distinct phages, designated Hh-1 and Hh-3, have been characterized. Both Hh-1 and Hh-3 are more tolerant of suspension in solutions of low ionic strength than their host bacteria. Both Hh-1 and Hh-3 have the ability to establish a carrier state upon infection of sensitive cells of H. halobium. Bacterial cells infected with phage in the carrier state are viable, produce phages, are immune to superinfection with homologous phages, yet remain fully capable of supporting heterologous phages. These properties suggest that the halophages are well adapted to survival in environments in which the salinity is subject to rapid changes of considerable magnitude.
The outermost surface structures in chroococcacean cyanobacteria
Authors: Vaara T.
Published: May 2010

This is the first comparative study on the nature and occurrence of the outermost surface structures in chroococcacean cyanobacteria. It shows that all the structures are similar to those of other bacteria and not specific to only cyanobacteria. Twenty-two chroococcacean strains (1 Microcystis, 7 Synechocystis, 12 Synechococcus, and 2 Gloeothece) were included in the study. Two Synechocystis strains had a glycocalyx layer. The two Gloeothece strains had a characteristic sheath, and the space between the sheath and the cells contained loosely packed material. On the basis of their preferential staining with ruthenium red, both the sheath and the loosely packed material most probably consist of acidic polysaccharides. Microcystis firma, three Synechocystis strains, and one Synechococcus strain were surrounded by a regularly structured surface layer consisting of hexagonally arranged subunits. Microcystis firma, all seven Synechocystis, and three Synechococcus strains possessed pili. The pili of some strains occurred as bundles. None of the strains produced spinae. Additionally, some structures described in previous studies are reinterpreted according to the findings of the present study.
Involvement of plasmids in determining bacteriophage sensitivity in Salmonella typhimurium: genetic and physical analysis of phagovar 204
Authors: Bezanson G. , Khakhria R. , Lacroix R.
Published: May 2010

Strains resistant to the action of sulfa drugs and tetracycline were predominant among the antibiotic-resistant Salmonella typhimurium phagovar 204 isolated in Canada. Plasmid DNA was detected in cellular extracts of all strains examined. A number of these plasmids could be placed in specific incompatibility and size classes. Both resistance coding and cryptic plasmids were involved in determining phagovar 204. In one instance, phagovar 204 was derived from phagovar 36 in a two-step conjugation involving independent sulfadiazine and tetracycline resistance plasmids. In another, phagovar 204 was derived directly from phagovar 49 through the introduction of a single tetracycline–streptomycin R plasmid. The phagovar-determining plasmids ranged in size from 3.4 to 72 megadaltons.
Attempts to detect by physicochemical methods plasmid DNA in mycoplasmas of human origin before and after transformation to tetracycline resistance
Authors: Saha Anil , Cerone Anna M. , Furness Geoffrey
Published: May 2010

Physicochemical methods have been used to compare mycoplasma DNA capable of the genetic transformation of tetracycline resistance with DNA from tetracycline-sensitive mycoplasmas and their transformants. These mycoplasmas were isolated from human patients. The DNA extracted from Mycoplasma hominis tetr resistant to 100 μg/mL tetracycline transforms tetracycline resistance to sensitive strains of Mycoplasma salivarium tets and Mycoplasma hominis tets but not Mycoplasma fermentans tets. Bulk DNA and DNA extracted by methods which increase the yield of circular DNA moieties were analyzed by cesium chloride and cesium chloride – ethidium bromide buoyant density ultracentrifugation and by horizontal and vertical agarose gel electrophoresis. Extrachromosomal DNA was not detected, which suggests that transformation was mediated by the recombination of chromosomal genes for tetracycline resistance and not by R factors. Moreover, no significant differences were detected in the DNA from the resistant and sensitive species or from their transformants and Mycoplasma fermentans tets which could not be transformed to resistance to 10 μg tetracycline/mL medium.
The metabolism of 3-cyclohexenecarboxylic acid by Alcaligenes faecalis
Authors: Blakley E. R. , Papish B.
Published: May 2010

Alcaligenes faecalis, grown on 3-cyclohexenecarboxylic acid supplemented with gluconate, was induced to metabolize cyclohexanecarboxylic acid, 3-cyclohexenecarboxylic acid, 1, 4-cyclohexadienecarboxylic acid, benzoic acid, and catechol. During growth, 1, 4-cyclohexadienecarboxylic acid, 3-heptene-1, 7-dioic acid, and benzoic acid were shown to be present in the culture supernatants. The results suggest that 3-cyclohexenecarboxylic acid may be metabolized by two pathways having 1, 4-cyclohexadienecarboxylic acid as a common intermediate. One pathway involved β-oxidation of coenzyme A intermediates; the other pathway involved benzoic acid as an intermediate. Studies on the consumption of oxygen per mole of substrate by cell suspensions indicated that the major portion of 3-cyclohexenecarboxylic acid was metabolized by the pathway involving benzoic acid. When grown on 3-cyclohexenecarboxylic acid as sole carbon and energy source, the organism was additionally induced to metabolize salicylic acid and gentisic acid, and growth medium contained salicylic acid. Thus, under the latter growth conditions a pathway involving salicylic acid as an intermediate was also induced.
Predominance of hydrogen-utilizing bacteria among N2-fixing bacteria in wetland rice roots
Authors: Watanabe I. , Barraquio W. L. , Daroy Maria Luisa
Published: May 2010

Heterotrophic bacteria were isolated from wetland soil, rhizosphere soil, root and basal shoot of wetland rice, dryland soil, and root of dryland rice. The isolates were tested for N2-fixing activity and the ability to grow autotrophically under H2 + CO2 + O2. N2-fixing bacteria capable of autotrophic growth were found almost exclusively from the rhizosphere and the root of wetland rice. In another experiment, all N2-fixing bacteria isolated from wetland rice root had uptake hydrogenase activity. These findings indicate the predominance of hydrogen-utilizing bacteria among N2-fixing bacteria from wetland rice roots.
Inhibition of amino acid transport and enhancement of tryptophan binding in a water mold by a range of natural and synthetic cytokinins
Authors: Léjohn Herb B. , Stevenson Roselynn M.
Published: May 2010

Approximately 30 purine compounds were examined for their influence on the energy-linked amino acid transport systems of Achlya (a freshwater mold). Most of them were inhibitory, and their effectiveness was related to (a) the presence of a substituent group at position 6 of the purine ring, (b) the length of hydrocarbon chain as substituent, and (c) the type of linkage between the substituent group and the heterocyclic ring. The most effective linkage group was SH followed by an NH2 group, and an oxygen bridge which was the least effective. Inhibition was immediate (suggesting an interaction with the cell membrane) and pH and temperature dependent. Only tryptophan uptake was anomalous, for while its transport was inhibited, its binding to a cell wall – membrane proteoglycan was stimulated severalfold. From kinetic studies, we deduced that the analogues and tryptophan were interacting with the same cell entity. Nucleoside forms of the analogues did not inhibit amino acid transport; this was understandable, since nucleosides are transported by an energy-linked system whereas nucleic acid bases are not. The purine analogues themselves were taken up very poorly by this organism.
Les peptide-hydrolases des lactobacilles du groupe Thermobactetium. I. Mise en évidence de ces activités chez Lactobacillus helveticus, L. acidophilus, L. lactis et L. bulgaricus
Authors: Soda M. El , Desmazeaud M. J.
Published: May 2010

The intracellular peptide hydrolase activities of Lactobacillus helveticus, L. acidophilus, L. lactis, and L. bulgaricus were determined using various aminopeptidase, dipeptidase, and carboxypeptidase substrates in addition to casein and whey protein fractions. The different activities were then separated using disc gel electrophoresis. Each bacterium had aminopeptidase activity towards various amino acid β-naphthylamides and dipeptides. The four species also showed bands of true dipeptidase activities on a large number of dipeptides. Intracellular enzymes from thermophilic lactobacilli also hydrolysed the whey proteins (α-lactalbumin and β-lactoglobulin). From the results of electrophoresis on β-casein and αs1-casein it was shown that β-casein was totally hydrolysed by L. lactis while it was only partially hydrolysed by the intracellular enzymes of L. acidophilus and L. bulgaricus. On the other hand, αs1-casein was only partially hydrolysed by L. helveticus, L. lactis, and L. bulgaricus.
Behavior of colorless appressoria in an albino mutant of Colletotrichum lagenarium
Authors: Suzuki K. , Kubo Y. , Furusawa I. , Ishida N. , Yamamoto M.
Published: May 2010

Spores of an albino mutant of Colletotrichum lagenarium formed colorless appressoria. The appressoria germinated laterally and formed secondary appressoria after further incubation. Appressorial formation was accompanied by nuclear division and migration of the spore contents into the primary appressorium. When the primary appressorium was mature, the nucleus in the spore had disappeared and the spore appeared empty. Similar phenomena were observed in the formation of secondary appressoria from primary appressoria. Formation of both primary and secondary appressoria was temperature sensitive. When spores were incubated in the presence of cycloheximide after 1 h of incubation, formation of primary and secondary appressoria was not affected. Secondary appressoria pigmented by addition of 3,4-dihydroxyphenylalanine could penetrate nitrocellulose membranes.
Differences in the regulation of exocellular proteinase synthesis during growth and sporogenesis of Bacillus megaterium
Authors: Chaloupka J. , Severin A. I. , Sastry K. J. , Kučerová H. , Strnadová M.
Published: May 2010

Bacillus megaterium 27 produces one exocellular metalloproteinase during growth as well as during sporogenesis. The formation of the enzyme during growth is repressed by the addition of amino acids of the leucine–isoleucine group. Its synthesis during sporogenesis is rather insensitive to repression. The enzyme is formed during the first 90 min after transfer to a sporulation medium, amino acids delaying only the onset of its synthesis as well as the onset of sporogenesis. The synthesis of the proteinase in asporogenic B. megaterium KM1 is repressed by amino acids during growth as well as during incubation in the sporulation medium and proceeds for a longer time under the latter condition. The results suggest that the formation of the proteinase during growth may be controlled differently from that during sporulation.
In vitro antifungal activity of eugenol and vanillin against Candida albicans and Cryptococcus neoformans
Authors: Boonchird Chuenchit , Flegel T. W.
Published: May 2010

Eugenol and vanillin were examined for in vitro antifungal activity against the medically important yeasts, Candida albicans and Cryptococcus neoformans. Minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) were determined for each compound against 31 strains of C. albicans and 33 strains of C. neoformans. With eugenol, the mean MIC's for C. albicans and C. neoformans were 625 and 293 μg/mL, respectively, while the mean MFC's were 1209 and 521 μg/mL, respectively. With vanillin, the mean MIC's for C. albicans and C. neoformans were 1250 and 738 μg/mL, respectively, while the mean MFC's were 5000 and 1761 μg/mL, respectively. With C. albicans, inhibition and retardation of growth were similar for yeast and mycelial forms, but germ tube formation was inhibited at concentrations lower than those which inhibited growth. Short-term toxicity tests with mice using the intraperitoneal route gave maximum tolerated doses of 62.5 mg/kg for eugenol and 125 mg/kg for vanillin and excluded their use as therapeutic agents for systemic mycoses.
Demonstration of an external layer in several species of the genus Brucella
Authors: Oberti Jean , Caravano René , Roux Jacques
Published: May 2010

An external layer suggesting a capsule was demonstrated by electron microscopy on three strains of Brucella belonging to different species. This structure was disclosed only after the action of antibodies and was not present on all the bacteria examined; labelling with conjugated specific antibodies showed that it incorporates and transports antigens belonging probably to the outer membrane. Staining by ruthenium red showed that it contains acidic mucopolysaccharides.
Tetrapyrrole utilization by Bacteroides fragilis
Authors: Fuller Mike D. , Caldwell Daniel R.
Published: May 2010

During growth in a defined medium containing protoheme, Bacteroides fragilis strain 2044 and Bacteroides "ℓ" 7CM formed protoheme-containing b-type cytochromes. The major reduced versus oxidized spectral peaks found for strain 2044 were at 562 and 428 nm whereas the peaks observed for strain 7CM were at 559 and 427 nm. When protoheme was replaced by deuteroporphyrin, mesoporphyrin, or their manganese or magnesium chelates, both organisms formed deuteroheme- or mesoheme-containing cytochromes with difference spectral peaks at 546 to 547 nm and 411 to 413 nm. Pyridine hemochromogen spectra of cells grown in the presence of tetrapyrroles containing the deuteroporphyrin or mesoporphyrin moiety confirmed the presence of deuteroheme or mesoheme in the cells. Although capable of delayed and relatively scant growth in media devoid of added tetrapyrroles or in media containing the vanadium chelates of mesoporphyrin or deuteroporphrin, neither organism formed cytochromes under these growth conditions. The functional nature of the cytochromes containing deuteroheme or mesoheme was confirmed by their reduction by cells in the presence of 56 mM glucose and carbon dioxide compared with cells exposed to air. The use of tetrapyrroles by strains 2044 and 7CM is similar to that previously found for Bacteroides ruminicola ssp. ruminicola. Versatility in tetrapyrrole utilization for cytochrome synthesis appears to be a common characteristic of heme-requiring gastrointestinal Bacteroides species.
Ethanol fermentation of enzymatically hydrolysed pretreated wood fractions using Trichoderma cellulases, Zymomonas mobilis, and Saccharomyces cerevisiae
Authors: Saddler J. N. , Hogan C. , Chan M. K.-H. , Louis-Seize G.
Published: May 2010

Several highly cellulolytic fungi were initially screened for their cellulase and β-glucosidase activities. Culture filtrates from Trichoderma E58 demonstrated the highest β-glucosidase activity, giving a value of 1.0 IU/mg protein. A variety of different cellulose and pretreated wood substrates were hydrolysed by various cellulase preparations. The importance of the pretreatment conditions and ensuing chemical extractions of the cellulosic substrates was demonstrated by the range of sugar and ethanol values obtained after saccharification and fermentation of the liberated sugars. The rate of hydrolysis of the cellulosic substrate by Trichoderma E58 culture filtrates, concentrated culture filtrates, and whole cell cultures was compared. An ethanol value of 2.2% (w/v) could be obtained after hydrolysis of 5% Solka floe by concentrated culture filtrates of Trichoderma E58 and fermentation of the liberated sugars by Zymomonas mobilis or Saccharomyces cerevisiae.
Varying electrophoretic mobility of an esterase caused by a factor in extracts of Bacillus stearothermophilus cells
Authors: Majima Eiji , Abe Mikiko , Higashi Shiro
Published: May 2010

The esterase pattern on polyacrylamide gel of extracts from Bacillus stearothermophilus grown at different temperatures from 45 to 71 °C was examined by slab gel electrophoresis. The esterase pattern showed the presence of eight esterase bands in the extracts from bacterial cells grown at 60 °C. These bands could be divided into two groups. One group included seven esterase bands which showed constant electrophoretic mobilities at different growth temperatures. The other group included one esterase band, Est-b, which showed different mobilities depending on growth temperature. A factor, which increased the mobility of Est-b, could be separated from cell extracts by gel filtration. The mobility of partially purified Est-b was regulated by addition of various amounts of the factor. At 70 °C, the thermostability of partially purified Est-b was increased by adding the factor; this was accompanied by competitive inhibition of the enzyme activity.
Enhanced removal of Mn2+ from seawater by marine sediments and clay minerals in the presence of bacteria
Authors: Ehrlich Henry L.
Published: May 2010

One of four different sediment samples from the Pacific ocean bound Mn2+ in a form which certain marine bacteria could then oxidize, provided that the sediment had been activated by pretreatment with ferric chloride in the laboratory. Cell extracts of one of the bacteria could oxidize Mn2+ sorbed by the same sediment even without pretreatment of iron. Leaching this sediment with concentrated HCl did not destroy its ability to sorb Mn2+ in biooxidizable form, indicating that neither carbonate nor ferromanganese was the active component in the sediment. However, acid treatment altered the sediment in such a way that intact cells of Oceanospirillum BIII 45 oxidized Mn2+ bound by it only without prior ferric chloride pretreatment, while four other test cultures still required ferric chloride pretreatment to oxidize the bound Mn2+. Azide inhibited oxidation of Mn2+ bound by iron-pretreated active sediment using intact cells and of Mn2+ bound by unpretreated active sediment using cell extract. Clay minerals of the montmorillonite and kaolinite types but not of the illite type, all of nonmarine origin, also sorbed Mn2+ in a form oxidizable by Oceanospirillum BIII 45. Ferric chloride pretreatment of these clays was needed when intact cells but not cell extract of the test cultures were used. The active components in the marine sediments may thus have been montmorillonite or kaolinite or both.
Heterogeneity of the yeast flora in the breeding sites of cactophilic Drosophila
Authors: Barker J. S. F. , Toll G. L. , East P. D. , Miranda M. , Phaff H. J.
Published: May 2010

Yeasts were isolated from 278 rots in cladodes and basal stems of Opuntia stricta sampled over 15 months at one locality. The most common yeast species among 370 nonidentical isolates representing 20 species were Candida sonorensis (27% of isolates) and Pichia cactophila (24%). These species generally were present in all months and throughout the area sampled. Other relatively common species (3–9% of alt isolates) had much more restricted distributions in both time and space. The mean number of yeast species per rot was 1.27 ± 0.082, and no yeasts were isolated from 20% of the rots sampled. Significant differences among months or seasons in average number of yeast species per rot were due primarily to lower numbers in the summer and winter months, while differences among rot types resulted mainly from a higher number in the longer persisting basal stem rots. Both hierarchical diversity analysis and analysis of the distributions of the 10 most common yeast species showed temporal effects (month or season) to be the major component contributing to heterogeneity, while microgeographic effects and rot type also were significant. The seasonal and microgeographic heterogeneity are interpreted in terms of longer persisting rots in part of the locality providing a reservoir for yeast species through the winter and are discussed in relation to the maintenance of genetic variation in cactophilic Drosophila that utilize the rots as feeding and breeding sites.
Molecular evidence for a close phylogenetic relationship among box-shaped halophilic bacteria, Halobacterium vallismortis, and Halobacterium marismortui
Authors: Nicholson Diarmuid E. , Fox George E.
Published: May 2010

The 5S rRNAs from Halobacterium vallismortis, Halobacterium marismortui (the Ginzburg strain), and two extremely halophilic isolates that exhibit an unusual "box-shaped" morphology were examined by ribonuclease T1 fingerprinting. The 5S rRNAs are found to be essentially identical and it is concluded that the four strains are in fact close phylogenetic relatives that should properly be assigned to a single genus. Comparison with previously available 5S rRNA sequence data from Halobacterium cutirubrum and Halococcus morrhuae indicates that the four strains examined here are quite distinct from both. It is further argued that this molecular evidence is not inconsistent with the previously proposed creation of a new genus, Haloarcula.
Plasmids of Pseudomonas syringae: no evidence of a role in toxin production or pathogenicity
Authors: Currier T. C. , Morgan M. K.
Published: May 2010

Forty strains of Pseudomonas syringae were analyzed for the presence of plasmids. Of the 21 strains known to produce syringomycin 9 contained plasmids, and of the 10 strains known to produce syringotoxin all contained at least one plasmid. Seven of the remaining nine strains produced a toxin which has not been identified. Of these strains two were shown to contain plasmids. These results suggest that strains exist which do not contain plasmids but produce syringomycin or an unidentified toxin. The same cannot be said for the syringotoxin-producing strains, since all strains examined contained plasmids. In addition, four plasmids have been eliminated from two syringomycin-producing strains with no effect on toxin production or pathogenicity. At present there is no evidence to suggest that any of the plasmids observed in this study are involved with toxin production or pathogenicity.
A survey of enteric viruses in domestic sewage
Authors: Payment Pierre , Ayache Reda , Trudel Michel
Published: May 2010

In this second study (1979–1981) of the viral content of sewage we have demonstrated the presence of poliovirus types 1, 2, and 3 in Laval and Montreal. Several strains of poliovirus types 2 and 3 were nonvaccinal. This is in contrast with our first study (1977–1978) in which only type 1 poliovirus isolates were nonvaccinal. Coxsackievirus types B-3, B-4, and B-5 and echovirus types 1, 7, and 11 were also isolated from sewage. Interestingly, these isolations coincided with reports of isolation of the same strains during the same period by diagnostic laboratories. Our method based on Vero and BSC-1 cell cultures for virus isolation and immune electron microscopy for identification permitted the recovery not only of several strains of enteroviruses but also of some adenoviruses and reoviruses.
Degradation of phenol by Streptomyces setonii
Authors: Antai Sylvester P. , Crawford Don. L.
Published: May 2010

Streptomyces setonii 75Vi2, a thermotolerant actinomycete from soil, was grown at 45 °C in a liquid medium containing phenol. The enzymes for phenol catabolism were inducible. Phenol hydroxylase catalyzed the NADPH-dependent hydroxylation of phenol to catechol, which was then cleaved by catechol 1,2-dioxygenase to cis,cis-muconic acid. This is the first report of phenol metabolism in the genus Streptomyces.
Pullulan production from peat hydrolyzate
Authors: LeDuy Anh , Boa Jacques Mian
Published: May 2010

Peat hydrolyzate was used as the substrate for the production of pullulan with Aureobasidium pullulans. Under nonoptimal conditions, as much crude polysaccharide was obtained in peat hydrolyzate medium as in the glucose synthetic medium.
Chemostat competition of alkaline phosphatase regulatory mutants in Escherichia coli
Authors: Francis J. C. , Beary D. A.
Published: May 2010

Mutant strains of Escherichia coli were isolated with different levels of constitutive synthesis of alkaline phosphatase. They were competed against wild-type revetant strains in glucose-limited chemostat cultures where alkaline phosphatase was not required for growth. Mutant strains were displaced by wild-type strains at rates dependent on their level of constitutivity.
Conservation of genetic information between different Rhizobium species
Authors: Jarvis B. D. W. , Scott K. F. , Hughes J. E. , Djordjevic M. , Rolfe B. G. , Shine J.
Published: May 2010

Transposon mutagenesis was used to generate nodulation (Nod−) and nitrogen fixation (Fix−) mutants of Rhizobium trifolii SU843. Total DNA isolated from mutant clones was digested with EcoR1 and cloned into plasmid pBR322. Recombinants carrying the Tn5 transposon and flanking Rhizobium DNA sequences were used to probe a gene fbank prepared from wild-type R. trifolii SU843 and to identify DNA sequences containing Nod+ or Fix+ genes which were capable of restoring biological functions in the mutants by genetic complementation. Cloned nodulation sequences derived from this work were hybridized with EcoR1 digests of DNA from other fast-growing rhizobia. The strains used represent several cross-inoculation and DNA homology groups found among these rhizobia. The extent to which individual cloned sequences were conserved varied from one strain of Rhizobium to another. In general, clones sequences were most highly conserved between strains belonging to the same homology group as the donor strain and had diverged most in strains classified in homology groups remote from that of the donor.
Accumulation du cadmium par Mytilus edulis en présence de souches bactériennes sensibles ou résistantes à ce métal
Authors: Flatau Gilles N. , Gauthier Michel J.
Published: May 2010

The role of cadmium resistant or sensitive marine bacteria in the accumulation of this metal by the viscera, gills, and mantle of Mytilus edulis was investigated. When the mussels were simultaneously given ionic cadmium and noncontaminated resistant bacteria, the accumulation of the metal by the whole soft part of the mussels was lower than that in the presence of the sensitive strain, or without bacteria added. The accumulation of the metal after the ingestion of bacteria previously contaminated by the cadmium and then killed was greater than that of ionic cadmium and was greater when the metal was bound to the resistant strain.
An alternative pathway for 3-phosphoglycerate generation in Veillonella
Authors: Pestka J. J. , Delwiche E. A.
Published: May 2010

Previous investigations have shown that members of the genus Veillonella possess the enzymes for a reversed glycolytic pathway of gluconeogenesis. Enzymatic and radioisotopic analysis of transformations occurring among C2 and C3 fragments in lactate-grown Veillonella alcalescens cell extracts revealed evidence for a second, novel mode of 3-phosphoglycerate biosynthesis involving the intermediates glyoxylate and glycerate. In this alternative pathway, malate is first cleaved in the presence of ATP by the action of a malate-ATP lyase to yield glyoxylate. Glyoxylate carboligase catalyzed the condensation of two molecules of glyoxylate to form CO2 and a C3 intermediate tentatively identified as hydroxypyruvate. Hydroxypyruvate is reduced to glycerate in the presence of NADH or NADPH by glycerate dehydrogenase. A glycerate kinase was purified 168-fold and shown to catalyze the ATP-dependent phosphorylation of glycerate to 3-phosphoglycerate. Glyoxylate reductase activity which could utilize NADH or NADPH as electron donors was also detectable.
The outer membrane of Haemophilus influenzae type b: cell envelope associations of major proteins
Authors: Coulton J. W. , Wan D. T. F.
Published: May 2010

Membrane proteins fom the cell envelope of Haemophilus influenzae type b ATCC 9795 were examined by sodium dodecyl sulphate – polyacrylamide gel electrophoresis. When envelopes were extracted with a phosphate-based buffer containing 2% Triton X-100, a major protein of molecular weight 43 000 was detected in fractions containing cytoplasmic membrane proteins. The cell wall material which was Triton X-100 insoluble contained six major proteins of molecular weights 46 000, 40 000, 36 000, 30 000, 27 000, and 16 000. One of these proteins showed a shift in molecular weight from 27 000 to 36 000 when it was heated over a temperature range from 50 °C to 100 °C in buffer containing 2% sodium dodecyl sulphate, 5% 2-mercaptoethanol. This alteration in mobility could be demonstrated either by the membrane-bound form of the protein or by a detergent-soluble form of the protein. Enriched preparations of the 36 000 molecular weight form were obtained by a series of purification steps. Extraction of the Triton X-100 insoluble material with buffer containing 2% Triton X-100, 5.0 mM EDTA yielded chiefly one major protein molecular weight 30 000 and many minor protein species. Pretreatment of the Triton X-100 insoluble fraction with lysozyme followed by extraction with buffer containing 2% Triton X-100, 5.0 mM EDTA released two proteins of molecular weights 16 000 and 27 000 and few minor proteins. By these operational manipulations, the proteins of molecular weights 16 000 and 27 000 may be considered as peptidoglycan-associated proteins.
Production of antibacterial activities by two Bacillariophyceae grown in dialysis culture
Authors: Cooper Sam , Battat Aviva , Marsot Pierre , Sylvestre Michel
Published: May 2010

Using a dialysis culture system for marine algae which allows for the recovery of high cell yield, we detected in the aqueous phase of the algal extracts an active component which inhibited gram-negative bacteria. Results show a direct relation between cell growth phase at time of harvest and the activity observed. It was possible to confirm previous results whereby Bacillariophyceae produce lipophilic substances inhibiting gram-positive terrestrial and marine bacteria. These findings corroborate the observation that Skeletonema costatum is more active man Phaeodactylum tricornutum against Staphyloccoci.