bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of the genes for hydrogenase and cytochrome c3 in Desulfovibrio
Authors: Voordouw Gerrit , Kent Helen M. , Postgate John R.
Published: May 2010

Cloned genes encoding cytochrome c3 and hydrogenase from Desulfovibrio vulgaris Hildenborough have been used to probe the genomes of 15 other desulfovibrios. The D. vulgaris strains Wandle and Brockhurst Hill cannot be distinguished from the Hildenborough strain by Southern hybridization using either probe, indicating similar genomes. Desulfovibrio vulgaris Groningen is completely different and lacks homologous cytochrome c3 and hydrogenase genes. The genomes of D. vulgaris ssp. oxamicus Monticello and D. desulfuricans strains El Agheila Z, Berre sol, and Canet 41 contain genes encoding a homologous but not identical periplasmic hydrogenase and cytochrome c3. Weak hybridization was observed with the cytochrome c3 gene probe for genomes of seven other sulfate-reducing bacteria, which reflects the known amino acid sequence divergence of cytochrome c3 in Desulfovibrio. The hydrogenase gene probe shows weak hybridization to the DNA from two strains of D. salexigens only, while the gene may be absent from D. vulgaris Groningen, two strains of D. africanus, D. thermophilus, D. gigas, and D. desulfuricans strains Norway and Teddington R. In desulfovibrios carrying cryptic plasmids the cytochrome c3 and hydrogenase genes are apparently chromosomal.
Purification and characterization of an α-L-arabinofuranosidase from Clostridium acetobutylicum ATCC 824
Authors: Lee S. F. , Forsberg C. W.
Published: May 2010

An α-L-arabinofuranosidase (EC 3.2.1.55) has been purified from the extracellular culture fluid of Clostridium acetobutylicum ATCC 824 and characterized. The enzyme was a single polypeptide with a molecular weight of 94 000, an isoelectric point of 8.15, and a pH optimum between pH 5.0 and 5.5. The Km and Vmax values for p-nitrophenyl-α-L-arabinofuranoside were 4.0 mM and 36.4 μmol∙min−1·mg protein−1, respectively. The enzyme had practically no activity against other p-nitrophenylglycosides with the exception of p-nitrophenyl-α-D-glucoside which it hydrolysed at 9% of the rate exhibited on p-nitrophenyl-α-L-arabinofuranoside. It degraded arabinan in an exo-manner, but exhibited no activity on carboxymethylcellulose, arabinogalactan, arabinoxylan, or oat spelt xylan. However, when it was incubated with the purified xylanase B, also obtained from C. acetobutylicum, it acted cooperatively to increase the rate of hydrolysis of oat spelt xylan. Arabinose was detected as one of the hydrolysis products.
Proficiency testing of conventional drug susceptibility tests of Mycobacterium tuberculosis
Authors: Laszlo Adalbert , Helbecque Dorothy M. , Tostowaryk Walter
Published: May 2010

Proficiency testing of indirect drug susceptibility tests of Mycobacterium tuberculosis was begun in 1985 by the Laboratory Centre for Disease Control (LCDC) with the participation of Provincial Public Health Laboratories in Canada. Comparable sets of 60 cultures of Mycobacterium tuberculosis representing 30 strains were distributed by LCDC to the participating laboratories to be tested for drug susceptibility against isoniazid, streptomycin, rifampin, and ethambutol using conventional methodologies. Intralaboratory agreement values determined by comparing results obtained on sets of duplicate cultures were high and were found to vary little from drug to drug and from laboratory to laboratory. Interlaboratory agreement was determined by comparing results reported by participating laboratories to those obtained by the Reference Laboratory. Agreement percentages were found to be lower for drug-resistant cultures than for drug-susceptible cultures. The reliability of drug susceptibility testing results was higher for isoniazid and rifampin, than for ethambutol and streptomycin. This study shows that the higher subsidiary drug concentrations do not compare well with main drug concentrations, especially in the case of streptomycin and ethambutol. The significance of the higher subsidiary concentrations in in vitro susceptibility testing is therefore in need of clarification. The proficiency testing results obtained in this study compare favorably with those reported in other developed countries despite the fact that a variety of testing procedures are used throughout the country.
Purification and characterization of adhesive exopolysaccharides from Pseudomonas putida and Pseudomonas fluorescens
Authors: Read R. R. , Costerton J. W.
Published: May 2010

In this study, the adhesive exopolysaccharides of strains of Pseudomonas putida and P. fluorescens, both isolated from freshwater epilithic communities, were examined with regard to their chemical composition, biosynthesis, and their role in adhesion. Electron microscopy showed that both strains were enrobed in fibrous glycocalyces and that these structures were involved in attachment of the cells to a solid surface and as structural matrices in the microcolony mode of growth. In batch culture experiments most of the extracellular polysaccharide of both strains was found to be soluble in the growth medium rather than being associated with bacterial cells. Exopolysaccharide was synthesized during all phases of growth, but when growth was limited by exhaustion of the carbon source, exopolysaccharide synthesis ceased whereas exopolysaccharide synthesis continued for some time after cessation of growth in nitrogen-limited cultures. Exopolysaccharide from both strains was isolated and purified. Pseudomonas putida synthesized an exopolysaccharide composed of glucose, galactose, and pyruvate in a ratio of 1:1:1; the P. fluorescens polymer contained glucose, galactose, and pyruvate in a ratio of 1:1:0.5, respectively. Polymers from both strains were acetylated to a variable degree.
Observation on a 65-kilodalton protein isolated from kanagawa positive strains of Vibrio parahaemolyticus
Authors: Sarkar B. L. , Kumar R. , De S. P. , Pal S. C.
Published: May 2010

Crude hemolysin from four KP+ strains of Vibrio parahaemolyticus belonging to serotype 02:K3 exhibited a major protein band (molecular weight, 65 kilodaltons (kDa)) in addition to a previously known thermostable direct hemolysin band (molecular weight, 21 kDa) in SDS – polyacrylamide slab gel electrophoresis. These strains showed maximum virulence leading to 100% mouse lethality within 2-6 h. It is hypothesized that this 65-kDa protein may play a vital role in the pathogenesis of the disease caused by V. parahaemolyticus.
Glucose-stimulated acidogenesis by Streptomyces peucetius
Authors: Dekleva Michael L. , Strohl William R.
Published: May 2010

Cultures of Streptomyces peucetius often were observed to divert spontaneously from the production of anthracycline antibiotics to the excretion of acidic metabolites, whether grown in a defined medium or a nutrient-rich medium. The predominant excreted acidic metabolites were determined by high-performance liquid chromatography to be pyruvate and 2-oxoglutarate. The acidification occurred at high frequencies when glucose was the primary carbon source in a defined medium, at intermediate frequencies when fructose was the primary carbon source, and did not occur when either maltose, starch, or dextrin were used as primary carbon sources.
Growth characteristics in cell culture and pathogenicity in mice of two terrestrial rabies strains indigenous to Canada
Authors: Webster W. A. , Charlton K. M. , Casey G. A.
Published: May 2010

Two strains of street rabies virus from striped skunks (Mephitis mephitis) were used to infect either a murine neuroblastoma (NA 1300) or a baby hamster kidney (BHK-21/C13) cell culture and the cell infection rates were noted during 4 days postinfection. These cultures were then passaged for four consecutive passages, and the viruses obtained in the supernatant fluids of passage 4 were then treated as original isolates and used to infect both neuroblastoma and baby hamster kidney cells. The mortality period in Swiss white mice caused by the various virus suspensions was noted. The virus strain from the brain of skunks from Saskatchewan infected neuroblastoma and baby hamster kidney cells equally well, produced similar virus titres in supernatant fluids after four subcultures in both cell types, and appeared to produce similar mortality periods in mice from either the original brain tissue or from cell culture supernatant fluids. On the other hand, the virus from the brains of skunks from Ontario readily infected neuroblastoma but poorly infected baby hamster kidney cell cultures. Passage of this strain through four subcultures in both cell types produced virus titres in the supernatant fluids of equal magnitude. However, reisolation of the virus from the supernatant fluid of passage 4 in neuroblastoma cell cultures showed a similar pattern to that from the original brain, while the virus from baby hamster kidney cell passage supernatant fluid was considerably altered. Although the mortality period in mice was similar with virus from the brain and neuroblastoma cell cultures, this period was shortened when mice were inoculated with baby hamster kidney culture supernatant virus. Virus from the salivary glands of Ontario skunks readily infected both cell types, producing similar titres at 4 days postinfection. The mortality period of mice inoculated with salivary gland suspensions was shorter than of those inoculated with brain suspensions. These findings demonstrate differences in rabies street virus strains that may have affected diagnostic procedures.
Antibody inhibition of HeLa cell invasion by Yersinia enterocolitica
Authors: Schiemann D. A. , Nelson C. M.
Published: May 2010

Antisera were prepared in rabbits against formalized and heat-killed bacteria of Yersinia enterocolitica serotype O:5,27 and against formalized bacteria of serotype O:8. Both strains used for immunization demonstrated adhesion to and invasion of HeLa cells. Coating of the bacteria with antibody did not greatly alter adhesion (i.e., extracellular attachment) to HeLa cells; however, antibody against formalized bacteria of both serotypes inhibited HeLa cell invasion by the homologous and heterologous strains. The Fab fragments from purified immunoglobulins also demonstrated cross-reacting inhibition of HeLa cell invasion. Antibody against heat-killed bacteria of serotype O:5,27 had no inhibitory activity. Adsorption of the antiserum against formalized bacteria of serotype O:5,27 with lipopolysaccharide from the homologous strain removed anti-lipopolysaccharide antibody but did not remove the inhibitory activity. The antiserum against formalized bacteria of serotype O:8 showed no antibody against lipopolysaccharide from serotype O:5,27 and no agglutinins against heat-killed bacteria of this strain. From these results, it is tentatively suggested that protein structures are important in mediating epithelial cell invasion by Y. enterocolitica.
Extracellular constitutive production of pullulan-hydrolysing activity by Sclerotium rolfsii
Authors: Kelkar Hemant S. , Lachke Anil H. , Deshpande Mukund V.
Published: May 2010

Extracellular constitutive pullulan-hydrolysing activity was detected in Sclerotium rolfsii (1.05 μmol glucose equivalents liberated∙mL−1∙min−1) when cultivated in a synthetic medium containing starch as the carbon source. The influence of various inorganic nitrogen and carbon sources, surfactants, and organic supplements on the production of pullulan-hydrolysing activity was studied. In an optimized medium supplemented with 1% corn steep liquor, increased yields of enzyme activity (1.8 μmol∙mL−1∙min−1) were obtained. The enzyme was most active at pH 4.2 and was stable in the pH range of 3.5–5.5. The optimum temperature for pullulan hydrolysis was 50 °C and the activity was stable in the temperature range of 25–60 °C at pH 4.2 for 30 min. The Ea for the native enzyme from the Arrhenius plot with pullulan as a substrate was 22.6 kJ∙mol−1. The Km value for the native enzyme with pullulan as a substrate was 8.33 mg∙mL−1. The enzyme did not produce glucose or maltose from pullulan. Inability of the enzyme to rapidly decrease the specific viscosity (ηsp) of a 1% pullulan solution indicated susceptibility of α-(1 → 6) and not α-(1 → 4) linkages.
Aromatic metabolism by a 2,4-D degrading Arthrobacter sp.
Authors: Sandmann E. R. I. C. , Loos M. A.
Published: May 2010

A hypothesis that low molecular weight aromatic compounds, which occur naturally in the soil, may act as alternative substrates or inducers for the 2,4-dichlorophenoxyacetate (2,4-D) degrading enzyme system of an Arthrobacter sp. and maintain this enzyme system in the absence of 2,4-D, was examined experimentally. In a nonmanometric resting cell experiment, the 2,4-D adapted Arthrobacter sp. rapidly degraded 6 of the 12 aromatic compounds tested, and these 6 compounds were tested further with 2 additional aromatic compounds in manometric experiments with 2,4-D grown and citrate-grown cells. Homogentisic acid and catechol were oxidized more rapidly by 2,4-D grown cells than by cells grown on citrate medium. Thus, these two compounds could serve as alternative substrates for the 2,4-D degrading enzyme system of the Arthrobacter sp. In further manometric experiments, the 2,4-D degrading enzyme system in cells adapted to 2,4-dichlorophenol, catechol, or sodium benzoate was not induced.
Outer membrane porin protein of Haemophilus influenzae type b: pore size and subunit structure
Authors: Vachon Vincent , Kristjanson David N. , Coulton James W.
Published: May 2010

The 40-kDa porin protein of Haemophilus influenzae type b was reconstituted into proteoliposomes. The relative rates of diffusion of small uncharged sugars across the channels formed by this protein were determined by measuring the rates of osmotic swelling of the liposomes. From these rates, a pore diameter of 1.8 nm was estimated using the Renkin equation. A chemical cross-linking technique was used to investigate the oligomeric structure of the 40-kDa porin. Sodium dodecyl sulfate – polyacrylamide gel electrophoresis revealed the presence of porin dimers and trimers after reaction of the protein with dithio-bis-(succinimidyl propionate). These results confirmed that the porin of H. influenzae forms large water-filled channels and indicated that it probably exists as trimers in the outer membrane.
Suppression by the ColV,I-K94 plasmid of inhibitor sensitivities in ompA mutants of Escherichia coli
Authors: Reakes Claudia F. L. , Deeney Caroline M. M. , Goodson Margaret , Rowbury Robin J.
Published: May 2010

A series of ompA mutants derived from Escherichia coli K12 strains showed increased sensitivity (compared with the ompA+ parents) to aminoglycoside antibiotics and to other cationic agents including polymyxin B. One tested mutant also showed increased sensitivity to nafcillin and fusidic acid, but not to the hydrophilic ampicillin. All these inhibitor sensitivities in the ompA mutants were suppressed by ColV, I-K94 and by certain other ColV plasmids, but not by any of the other tested large plasmids. Suppression correlated with the production of the VmpA protein, but transfer and colicin components were not needed for suppression. Further comparison of the ompA and vmpA genes and their products was made and it indicated that there is little if any homology between the genes, that the synthesis of their products is regulated by quite different mechanisms, and that regions of these gene products exposed at the cell surface show different susceptibility to protease attack after denaturation.
Physiological regulation of protease activity in Streptomyces peucetius
Authors: Gibb Gregory D. , Strohl William R.
Published: May 2010

Streptomyces peucetius ATCC 29050, a producer of anthracycline antineoplastic agents, was investigated for the expression of intracellular and extracellular azocaseinase activities as a function of growth and medium conditions. When cultures were grown in either nitrate-containing defined medium or glucose – yeast extract complex medium, the intracellular proteolytic activity was greatest during early to mid stationary phase, whereas the extracellular proteolytic activity was produced in late stationary phase. All of the proteolytic activity detected against azocasein was of a serine-type protease activity. These late-occurring proteases may have some function in cellular turnover associated with secondary metabolism and (or) morphogenesis.
Comparison of three media used for the enumeration of heat-injured Botrytis cinerea
Authors: Day N. B. , Skura B. J. , Powrie W. D.
Published: May 2010

The efficacy of three media (antibiotic-supplemented plate count agar (3 days, 21 °C); antibiotic–pyruvate–supplemented plate count agar (3 days, 21 °C); and trypticase soy agar (16 h, followed by 2.5 days on antibiotic-supplemented plate count agar, 21 °C)) for recovery of heat-injured Botrytis cinerea spores was compared using hydrophobic grid membrane filters. The filters restrict spreading of fungal colonies and facilitate the transfer of fungal spores from pre-enrichment trypticase soy agar to antibiotic-supplemented plate count agar. Counts obtained from pre-enrichment on trypticase soy agar were significantly larger than counts obtained from the other media (α = 0.05). Addition of sodium pyruvate to antibiotic-supplemented plate count agar did not increase spore recovery (α = 0.05). The use of trypticase soy agar as a pre-enrichment medium should be considered for use when antibiotic-supplemented plate count agar is employed in the enumeration of heat-stressed fungi.
Chemotaxis of some phytopathogenic bacteria to fungal propagules in vitro and in soil
Authors: Lim W. C. , Lockwood J. L.
Published: May 2010

The motile plant pathogenic bacteria Erwinia carotovora pv. carotovora, Pseudomonas syringae pv. phaseolicola, and Xanthomonas campestris pv. campestris were strongly attracted to conidia of Bipolaris sorokiniana, B. victoriae, and to sclerotia of Macrophomina phaseolina and their exudates in vitro and in soil, but not to phosphate buffer or buffer–soil mixtures. Bacteria accumulated radioactivity within 1 h after being placed in exudates from 14C-labelled conidia of B. sorokiniana. After 5 h, radioactivity of the 14C-labelled exudate was reduced to 29–54% of that in the original medium. Exudates from fungal propagules may act as attractants and substrates for motile plant pathogenic bacteria in soil.
Differential glucoamylase expression in Schwanniomyces castellii induced by maltose
Authors: Dowhanick T. M. , Scherer S. W. , Willick G. , Russell I. , Stewart G. G. , Seligy V. L.
Published: May 2010

Different levels of glucoamylase expression occurred when Schwanniomyces castellii strain 1402 was shifted during growth on glucose to either glucose, maltose, or soluble starch medium. Extracellular glucoamylase activity was greatest from cells grown on maltose (~22×), slightly less on soluble starch (~16×), and least on glucose (1×). Glucoamylase biosynthesis was further studied by labelling of total proteins in vivo with [35S]methionine and immunoprobing with a polyclonal anti-glucoamylase antibody. Mature active glucoamylase is 146 kDa. Maltose cultures expressed four cellular (75, 78,138, and 146 kDa) and two extracellular (78 and 146 kDa) polypeptides. Neither the 138- nor the 146-kDa products were detected in cells in the presence of glucose; the 78-kDa product is expressed at approximately 5% the level obtained from cells in maltose. The 146-kDa glucoamylase is expressed within 30 min after transfer of cells from glucose- to maltose-containing medium. This expression appears to be cell growth and concentration independent and is therefore similar to galactose-inducible enzyme expression in Saccharomyces cerevisiae.
Restriction fragment length polymorphism and multiple copies of DNA sequences homologous with probes for P-fimbriae and hemolysin genes among uropathogenic Escherichia coli
Authors: Hull Sheila I. , Bieler Sandra , Hull Richard A.
Published: May 2010

Hemolysin and P-fimbriae are two virulence traits frequently found together in uropathogenic Escherichia coli. Previous studies have discovered evidence both for linkage between the genes for these traits and for their duplication in the chromosomes of a limited number of strains. To test whether these observations are characteristic of uropathogenic Escherichia coli, the method of DNA hybridization to DNA restriction fragments separated by electrophoresis and transferred to nylon was used to determine copy number of genes for P-fimbriae (pap) among 51 E. coli strains isolated from symptomatic urinary tract infections. Twenty percent of the strains had more than one copy of pap homologous sequences. Fifteen strains, each representing a unique clone, were examined for the presence of sequences homologous with cloned hemolysin genes (hly). Samples of DNA from 14 of the 15 strains hybridized with hly probes. In eight strains the number of copies of pap equalled the number of copies of hly, including one strain with two apparent copies of each. Five strains appeared to have one more copy of pap than of hly, and one strain had an extra copy of hly.
The spectrum of Escherichia coli – Bacteroides fragilis pathogenic synergy in an intraabdominal infection model
Authors: Rotstein O. D. , Kao J.
Published: May 2010

Pathogenic synergy between Escherichia coli and Bacteroides fragilis was investigated in an intraabdominal infection model. Defined inocula of E. coli and B. fragilis, alone or in combination, were enmeshed within a fibrin clot and surgically implanted into the peritoneal cavity of rats. A spectrum of bacterial synergy ranging from synergistic abscess formation to synergistic lethality was demonstrated using this model. The type of synergy exhibited was dependent upon the initial E. coli inoculum. When combined with B. fragilis, high inocula of E. coli (> 108 cfu/clot) produced synergistic lethality while low inocula (2 × 102 to 2 × 107 cfu/clot) resulted in synergistic abscess formation. With respect to abscess formation, there was reciprocal synergy between E. coli and B. fragilis. Abscesses resulting from mixed inocula were larger and had significantly higher numbers of E. coli and B. fragilis than abscesses initiated by monomicrobial inocula. These studies define a clinically relevant model of bacterial interactions in the setting of intraabdominal infection and suggest that conclusions drawn from experimental models of bacterial synergy should consider the type of model examined, the strains of bacteria studied, and the number of bacteria inoculated.
FOREWORD
Authors: Pickard M. A. , Westlake D. W. S.
Published: May 2010

In May 1952, the Canadian Journal of Microbiology published a special issue dedicated to Professor E. G. D. Murray of the occasion of his retirement from the Chair of Bacteriology and Immunology at McGill University. At that time the Journal was in its second year of publication and its editor was R. G. E. Murray.In the 32 years since that issue, R. G. E. Murray has become a scientist of the highest international reputation, and the Dean of Canadian microbiologists. His knowledge and expertise encompass a wide spectrum of activities, as a scientific editor, a teacher, an administrator, but most important as a researcher. Now, as a Professor Emeritus of Microbiology and Immunology at the University of Western Ontario, Professor R. G. E. Murray continues to practice his science at all levels: clearly a labour of love. In view of this continuing involvement in Microbiology, and as a mark of our respect for his accomplishments so far, the Canadian Journal of Microbiology has dedicated this issue to his achievements.Two of Professor Murray's former students, Terry Beveridge (Guelph) and Bill Costerton (Calgary) have organized and edited this issue. To them go the Journal's sincerest thanks for the many hours required to bring this issue together. As Canadian scientists, each with an international reputation, their efforts are a sincere tribute to their former mentor.This special issue also owes a debt of gratitude to the Section Editors: Bill Chesbro, Gerry Hazelbauer, and Noel Kreig who organized the individual sections. That they gave so generously of their time from busy schedules reflects the affection and regard of the international microbiology community for Bob Murray. We also thank the individual contributors: their willingness to become involved in this appreciation is a sincere token of esteem.
The bacterial surface: general considerations towards design and function
Authors: Beveridge T. J.
Published: May 2010

The shape of bacteria is determined by the wall which surrounds the protoplast. This enveloping structure resides in diverse chemical and organizational forms and is of fundamental importance for several aspects of cellular life and growth. This article discusses these general aspects and serves as an introduction to the journal issue and to the more specific papers which follow in the section.
Microbial invasion: a covert activity?
Authors: Gorby Gary L. , Robinson Jr. Edward N. , Barley Lee R. , Clemens Christopher M. , McGee Zell A.
Published: May 2010

In contrast to nonpathogenic microorganisms that exist happily in biofilms on various organic and inorganic surfaces, many pathogenic microbes have the additional ability to invade host tissues by inducing their own endocytosis and transport across normally protective barriers. This phenomenon, designated " parasite-directed endocytosis," has been observed with a variety of surfaces (intestinal, genital, nasopharyngeal, and tracheal epithelium) as well as in endothelial cells. The mechanisms involved in invasion may involve a single factor as described for some species of Yersinia, or may require multiple factors as observed in Shigellae. For the majority of pathogens, the molecular mechanisms of invasion are not well understood (e.g., Neisseria gonorrhoeae). Because parasite-directed endocytosis is reminiscent of receptor-mediated endocytosis, it is quite possible that some pathogens engage in biologic mimicry by producing a molecule that resembles a natural host ligand, for which there is a host cell receptor. Such a masquerade may allow some microbes to enter the host's inner sanctum covertly in a manner analogous to the Trojan horse, rather than overtly by destroying the mucosa and entering host tissues directly. Whereas this hypothesis is speculative at present, bacteria that produce molecules resembling insulin, calmodulin, and chorionic gonadotropin have been described.
Bacterial classification: an overview
Authors: Krieg Noel R.
Published: May 2010

Classification of bacteria evolved from limited subjective groupings to general, more objective arrangements based on overall phenotypic similarities. However, classifications based on phenotypic characters lack stability, whereas those based on genetic relatedness tend to be stable. DNA–DNA hybridization has proven to be extremely useful in resolving taxonomic problems at the species level. Broad relationships among bacteria have been identified by comparing ribosomal RNA cistrons; however, many groups based on ribosomal RNA analysis are not easily definable in terms of phenotypic similarities. Unless resolved, these problems could lead to the establishment of two separate classification systems, one phylogenetic and the other practical.
The ultrastructure and ATPase nature of polar membrane in Campylobacter jejuni
Authors: Brock F. M. , Murray R. G. E.
Published: May 2010

Polar membrane in Campylobacter jejuni has been visualized on membrane vesicles. It was composed of doughnut-shaped particles 5–6 nm in diameter, with stalks, arranged in a hexagonal array. This structure was stabilized on the membrane by a high ionic strength buffer in the presence of 2-mercaptoethanol. Histochemical staining indicated localized ATPase activity at the poles of the cells. An ATPase with distinctive properties has been isolated and purified from this organism; it gives a specific activity of approximately 0.3 units/mg of protein. Electron microscopy showed doughnut-shaped particles 5–6 nm in diameter. Nondissociating and sodium dodecyl sulfate – polyacrylamide gel electrophoresis of the purified enzyme revealed, respectively, a single band with ATPase activity and a molecular weight of ca. 75 – 000 Da. The enzyme was cold labile and activity was abolished by trypsin. Dicylohexylcarbodiimide inhibited the membranebound form of the enzyme, but did not inhibit the soluble form. Oligomycin had no inhibitory activity on either form of the enzyme. The enzyme specifically hydrolysed ATP, but other nucleotide substrates were not degraded. The enzyme was activated by Mg2+ and inhibited by Ca2+, whereas other ions had no effect on activity. Antibodies prepared to this enzyme bound to the polar regions of whole cells as shown by protein A – colloidal gold immunoelectron microscopy. The antibodies to this ATPase cross reacted (shown by Western blotting) with four proteins from a whole-cell extract of this organism, two proteins in Aquaspirillum serpens MW5, and three proteins from Escherichia coli K12. They did not cross-react with any proteins from Spirillum volutans, Methanococcus voltae, Vibrio cholerae, or rat liver mitochondria. Antibodies raised against the F1-ATPase of E. coli K12 cross reacted with six proteins in a whole-cell extract of this organism, and one protein species in each of the whole-cell extracts of V. cholera, A. serpens MW5, S. volutans, and rat liver mitochondria. These antibodies did not recognize any whole cell proteins from either C. jejuni or M. voltae. These results along with the ATPase activity localized by histochemical staining suggest that polar membrane is an assembly of ATPase molecules at the poles of the cell and that the ATPase isolated from C. jejuni is serologically and structurally unusual.
A study of fungal endoparasitism of the cereal cyst nematode (Heterodera avenae) by scanning electron microscopy
Authors: Lopez-Llorca L. V. , Duncan G. H.
Published: May 2010

The sequential development of fungal endoparasites from eggs of the cereal cyst nematode (Heterodera avenae) was studied by scanning electron microscopy using both critical point dried and frozen, fully hydrated specimens. Fully hydrated specimens were much closer to the natural state than those that had been critical-point dried. Several stages of fungal infection were observed that are similar to those reported for entomopathogenic fungi. Cereal cyst nematode eggs from white females or from cysts were examined before plating on agar. Eggs from both sources had two distinct shapes. This was caused by differences in the developmental stage of the eggs from white females and by the presence or absence of internal fungal material in eggs from cysts.
A highly efficient second-step concentration technique for bacteriophages and enteric viruses using ammonium sulfate and Tween 80
Authors: Armon Robert , Arella Max , Payment Pierre
Published: May 2010

Addition of Tween 80 to a 1.5% solution of beef extract was found to enhance the elution of bacteriophages adsorbed to electronegative filters. When reconcentration of the eluate was attempted by ammonium sulfate precipitation, a floating layer containing most of the viruses was formed. This floating layer can be obtained with several nonionic detergents including Tween 80 and under a salt saturation of 55% with ammonium sulfate, potassium tartrate, and sodium phosphate. Virus recovery ranged from 91 to 103% and was obtained with several bacteriophage strains. With poliovirus type 1, coxsackievirus B-4, and rotavirus SA-11 the recoveries were 100, 20, and 80%, respectively, but toxicity to cell culture was encountered: after removal of the detergent by a second floating layer method the recovery was 32% for poliovirus. Compared with organic flocculation, this method also had both improved recovery for bacteriophages and protective properties for samples frozen at −70 °C.
Growth of Listeria monocytogenes at different pH values in uncultured whey or whey cultured with Penicillium camemberti
Authors: Ryser Elliot T. , Marth Elmer H.
Published: May 2010

Wheys from making Camembert cheese were either uncultured or cultured with Penicillium camemberti, adjusted to pH 5.0, 5.2, 5.4, 5.6, 6.2, and 6.8, and filter sterilized. Whey samples were inoculated to contain 100 to 500 Listeria monocytogenes (strains Scott A, V7, CA, or OH) cfu/mL and incubated at 6 °C. Counts of L. monocytogenes were obtained by surface plating appropriate dilutions on Tryptose Agar. Listeria monocytogenes failed to grow at or below pH 5.4; except for strains Scott A and OH which grew in cultured whey at pH 5.4 and attained populations of 7.8 × 103 and 5.4 × 104 cfu/mL, respectively, after 35 d of storage. In uncultured whey at pH 5.6, 6.2, and 6.8, populations of L. monocytogenes increased from 7.20 to 7.81, 7.51 to 8.23, and 7.48 to 8.08 log10 cfu/mL, respectively, after 35 d of storage at 6 °C. In cultured whey at pH 5.6, 6.2, and 6.8, numbers of L. monocytogenes increased from 7.53 to 8.13, 7.82 to 8.55, and 7.95 to 8.80 log10 cfu/mL, respectively, after 35 d of storage. Generation times for L. monocytogenes at 6 °C in uncultured whey at pH 5.6, 6.2, and 6.8 ranged between 25.3 and 31.6 h, 14.8 and 21.1 h, and 14.0 and 19.4 h, respectively, depending on the Listeria strain. In contrast, generation times were significantly (p < 0.05) shorter in cultured whey and ranged between 16.6 and 27.4 h, 10.3 and 16.6 h, and 17.4 and 16.3 h at pH values of 5.6, 6.2, and 6.8, respectively.
Yeast flocculation: factors affecting the measurement of flocculence
Authors: Kihn Jean Claude , Masy Charlotte L. , Mestdagh Michèle M. , Rouxhet Paul G.
Published: May 2010

The physical meaning of the residual absorbance of a yeast suspension after flocculation and settling has been investigated. Starting with a dispersed suspension, agitation accelerates flocculation by increasing the probability of collision between particles. As flocculation advances, agitation also breaks the flocs. A stationary state is reached when flocculence (tendency to flocculate) is counterpoised by agitation. If the intensity of agitation is maintained constant, the free cell concentration reflects the flocculence, provided the stationary state is reached. The residual absorbance, determined after settling of the flocs, is a measure of the free cell concentration and represents an adequate parameter to characterize yeast flocculence.
Growth of nopaline-utilizing Agrobacterium and Pseudomonas in extracts of crown-gall tumors
Authors: Saint-Pierre B. , Dion P.
Published: May 2010

Two nopaline-utilizing bacteria isolated from the same crown-gall tumor, and identified previously as Agrobacterium tumefaciens and Pseudomonas aureofaciens, were grown in pure or dual culture in various types of media. These included minimal medium with nopaline as the sole carbon and nitrogen source, and intercellular fluid extracted from sunflower or apple. The size of inoculum was similar for the two bacteria, and the ratio of the maximal cell population for P. aureofaciens over that for A. tumefaciens was calculated. This ratio was highest for dual culture in minimal medium, and under these conditions P. aureofaciens utilized most of the nopaline supply. This advantage of Pseudomonas in terms of maximal cell population was reduced for dual cultures in extracts prepared either from uninoculated stems or from tumors that had been induced by the A. tumefaciens isolate. For the two plants studied, the difference between maximal populations of P. aureofaciens and A. tumefaciens was smaller in tumor than in stem extract. The time of disappearance of opines from the tumor extracts was considered in relation with the growth of the two bacteria. Similar analysis was made on cultures involving A. tumefaciens and a mutant pseudomonad deficient in nopaline utilization. These experiments indicated that the differential response of dual cultures of A. tumefaciens and P. aureofaciens to stem or tumor extracts was not due to the presence of opine of the nopaline family in the extracts from crown-gall tumors.
Structural and antigenic variation of the structural protein VP3 in serotype 1 poliovirus isolated from vaccinees
Authors: Cash Phillip
Published: May 2010

High resolution two-dimensional PAGE was used to analyse protein variation among serotype 1 poliovirus isolates. Viruses isolated from patients with recent histories of vaccination with live attenuated poliovirus were compared with prototype serotype 1 poliovaccine. The nonvaccine Mahoney and Brunenders strains of serotype 1 poliovirus were also analysed. The overall protein profile was conserved but the structural protein VP3 varied in its net charge among the viruses. Eight out of 14 clinical virus isolates had VP3 with a net basic charge identical to serotype 1 polio vaccine, whereas the remaining clinical isolates had an acidic VP3 similar to the nonvaccine type 1 strains. The altered VP3 mobility correlated with a change in antigenicity as determined by monoclonal antibodies directed to the neutralization site located on VP3. The data clearly illustrated the suitability of two-dimensional PAGE in analysing protein mutations in attenuated vaccine virus excreted by vaccinees.
H2 supports nitrogenase activity in carbon-starved Azospirillum lipoferum and A. amazonense
Authors: Fu Changlin , Knowles Roger
Published: May 2010

Exogenous H2 significantly increased nitrogenase activity in carbon-starved but not in carbon-sufficient N2-fixing cells of both Azospirillum lipoferum and A. amazonense. H2-supported C2H2 reduction increased as the H2 concentration was increased. The data indicate that H2 oxidation via hydrogenase may couple to ATP formation and provide some energy for nitrogenase under carbon limitation. However, the presence of H2 did not change the optimal O2 concentration for C2H2 reduction activity in either species, suggesting that H2 oxidation did not contribute respiratory protection for the cells. C2H2 at 5 kPa inhibited the uptake hydrogenase activities of N2-fixing A. lipoferum and A. amazonense by 10 to 12 and 7 to 8%, respectively. Such inhibition was increased to 38% by pre-exposure of the cells to C2H2 and was almost irreversible.
Evidence of cytokinin production by a marine bacterium and its taxonomic characteristics
Authors: Maruyama Akihiko , Yamaguchi Isomaro , Maeda Masachika , Simidu Usio
Published: May 2010

Cytokinin-active compounds produced by marine bacteria have been conclusively detected for the first time. A bacterial strain isolated from marine sediment produced cytokinin-active compounds extracellularly during the logarithmic phase of growth. Taxonomical examinations showed that this bacterium belonged to the genus Vibrio. The cytokinins were identified and quantified as isopentenyladenine (0.28 μg/L) and isopentenyladenosine (0.14 μg/L) by gas chromatography -mass spectrometric analysis of their trimethylsilyl derivatives. Results of a plasmid survey suggests that genes specifying the cytokinin biosynthesis in this bacterium are located on the chromosome, not on a plasmid.
Genetic regions of Pseudomonas aureofaciens strain 211 involved in nopaline catabolism
Authors: Beaulieu C. , Gill S. , Miville L. , Dion P.
Published: May 2010

A DNA fragment from the nopaline catabolism region of the Ti plasmid of Agrobacterium tumefaciens showed no detectable homology to the total DNA of several nopaline-utilizing strains of Pseudomonas spp. From one of these pseudomonads, Pseudomonas aureofaciens strain 211, mutants defective in the catabolism of nopaline but not arginine, have been obtained by mutagenesis with transposon Tn5, and also with TnV using a new suicide plasmid vector. The DNA fragment bearing the TnV insertion has been cloned and found to hybridize with DNA of every pseudomonad tested, independently of the capacity to utilize nopaline, but not with Agrobacterium DNA. In a separate experiment, nonmutagenized DNA of strain 211 was cloned in a cosmid vector. Transfer of one of these clones to Pseudomonas putida strain KT2440 conferred on the recipient the capacity for nopaline utilization. However, this cosmid clone was only partially functional, since it did not complement a TnV mutant.
Microbiological differences between soils suppressive and conducive of the saprophytic growth of Gaeumannomyces graminis var. tritici
Authors: Simon A. , Sivasithamparam K.
Published: May 2010

A soil acidified by ammonium sulphate following annual application of the fertilizer for 9 years was suppressive of the saprophytic growth of Gaeumannomyces graminis var. tritici in soil (pathogen suppressive). The same soil amended with lime was pathogen conducive. In natural field soil microbial respiration and the 'total' number of aerobic microorganisms were greater in the conducive than in the suppressive soil. In a soil-sandwich bioassay of the transferable suppression of saprophytic growth of the pathogen there were higher numbers of 'total' aerobic microorganisms, fluorescent pseudomonads, and Gram-negative organisms, but lower numbers of filamentous fungi and yeasts in the conducive than in the suppressive soil. It was estimated that Trichoderma spp. made up 71 and 34% of the total numbers of fungi counted in the suppressive and conducive soils, respectively. It is proposed that Trichoderma spp. played a major role in the transferable pathogen suppression in the suppressive soil.
The deoxyribonucleoprotein complex from the archaebacterium Methanosarcina barkeri: characterization and ultrastructural localization of the chromosomal protein MC1
Authors: Imbert Marlène , Laine Bernard , Prensier Gérard , Touzel Jean-Pierre , Sautière Pierre
Published: May 2010

The Methanosarcina barkeri protein, methanogen chromosomal protein 1 (MC1), a basic polypeptide of 93 amino acid residues, has been localized in the DNA-rich areas on immunolabelled bacterial cryosections revealed with the protein A – gold method. This localization strongly supports the previous studies concerning the association of the protein MC1 with the DNA in vivo. In the M. barkeri deoxyribonucleoprotein complex, the protein MC1 accounts for about 90% of the total proteins, and the protein MC1 so DNA ratio (by weight) is equal to 0.11. Staphylococcal nuclease digestion data and microscopic observations have failed to reveal the presence of repeating structural units and suggest that the protein MC1 is unevenly distributed along the DNA.
Stability and carbohydrate composition of chloroperoxidase from Caldariomyces fumago grown in a fructose–salts medium
Authors: Pickard Michael A. , Hashimoto Atsumi
Published: May 2010

The glycoprotein chloroperoxidase has been isolated from Caldariomyces fumago grown in a fructose-salts medium and some of its properties studied, including stability to pH and temperature and carbohydrate composition, as a preliminary to immobilization. At 22 °C, more than 50% of the activity remained after 15 days when the enzyme was maintained between pH 3.5 and 5.5; between pH 6 and 7 only 25% of activity remained after 4 days. At 40 °C and pH 5.5, enzyme activity was stable for 7 days. Carbohydrate composition studies were carried out on six isoenzymes of chloroperoxidase that were separated by isoelectric focussing on flat-bed Sephadex G-75 gels. After acid hydrolysis and derivatization, the carbohydrate components of the isoenzymes were analyzed by gas chromatography. The major components were found to be glucose and mannose, with xylose, galactose, and glucosamine present at levels less than 10% of the total. These results contrasted with those for the enzyme purified after growth of the fungus on glucose and malt extract, previously reported, where the carbohydrate components were identified as arabinose and glucosamine.
Effects of elevated temperature on growth, respiratory-deficient mutation, respiratory activity, and ethanol production in yeast
Authors: Yamamura Midori , Nagami Yoichi , Vongsuvanlert Vitchuporn , Kumnuanta Jaroon , Kamihara Teijiro
Published: May 2010

Some mesophilic yeasts and a thermotolerant strain of Saccharomyces cerevisiae were found to grow at 40 °C in complex media containing 1% yeast extract when an inoculum of 106 or more cells∙mL−1 was used. Yeast extract (6%) permitted Saccharomyces cerevisiae to grow at 40 °C even with a smaller inoculum size (105 cells∙mL−1). The fraction of respiratory-deficient (petite) mutants in 40 °C grown culture was less than 10% except for the thermotolerant strain, which showed greatly increased levels depending on culture conditions. Seven of eight yeast strains exhibited extremely reduced cytochrome oxidase activity when grown at 40 °C irrespective of the frequency of the petite mutation. In contrast, the accumulation of ethanol in the medium and the ethanol-producing activity of the cells were not affected by growth at 40 °C.
Rhizobitoxine production by and nodulation characteristics of colony-type derivatives of Bradyrhizobium japonicum USDA 76
Authors: Favre Jeffrey S. La , Favre Adrienne K. La , Eaglesham Allan R. J.
Published: May 2010

Bradyrhizobium japonicum strain USDA 76, a rhizobitoxine producer, was found to contain two colony types, designated "small" and "large" based on colony size on agar medium. Only the small type produced detectable chlorosis-inducing toxin in culture, whereas both colony types induced chlorosis as a result of synthesis of toxin in nodules. Electron microscopy revealed that a large colony derivative, grown in broth culture, was encapsulated, whereas a small colony derivative was not, suggesting a negative functional relationship between toxin synthesis and presence of capsule. The large type also had a ruthenium red reactive extracellular layer when cultured in the soybean rhizosphere. This differential production of toxin by the colony derivatives in culture, and presumably in the rhizosphere, prompted the investigation of a proposed role of rhizobitoxine in the infection of roots of nodulation-refractory (rj1rj1) soybean; the small colony type formed fewer nodules on the (rj1rj1) isoline, indicating no major function for rhizobitoxine in the infection of (rj1rj1) soybean.
Phage f2 desorption from clay in estuarine water using nonionic detergents, beef extract, and chaotropic agents
Authors: Armon Robert , Cabelli Victor J.
Published: May 2010

Experimentally adsorbed bacteriophage f2 was eluted from clay particles in estuarine water using 1% Tween, 80.3% beef extract, and 0.3 M NaNO3 with 54% recovery. Replacing sodium nitrate with tetrasodium pyrophosphate (0.4 M) increased the recovery to 81%. Estuarine sediments treated with 1% Tween 80 revealed significantly higher male-specific phage elutions.