bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of medium composition on cell pigmentation, cytochrome content, and ferric iron reduction in a Pseudomonas sp. isolated from crude oil
Authors: Obuekwe C. O. , Westlake D. W. S.
Published: May 2010

Cells of a pseudomonad associated with pipeline corrosion grown on a complex medium were orange in color and vigorously reduced ferric iron. The intensity of orange color of cells grown on a synthetic medium and their ability to reduce ferric iron was directly related to the iron content of the medium. Absorption spectrophotometric data show a direct relationship between color of cells, cytochrome content, and ability to reduce ferric iron. Carbon monoxide markedly, but not completely, inhibits the reduction of ferric iron. The data presented indicate that ferric iron can serve as a terminal electron acceptor for cytochrome-associated respiratory processes of this corrosive pseudomonad.
Evaluation of the immunogenicity of a CaCl2 extract from Neisseria meningitidis group Y
Authors: Bisaillon J. G. , McSween G. , Portelance V. , Kluepfel D. , Micusan V. V.
Published: May 2010

Cross-protection has already been demonstrated in mice after vaccination with a CaCl2 extract from the Neisseria meningitides group Y Slaterus strain. The immunogenicity of such extracts from group Y cells, cultivated in a fermenter in Neisseria chemically defined medium, against virulent groups A, B, and C meningococci has been evaluated by two different animal models and a microbactericidal procedure. The mouse challenge system has revealed that the active cross-production observed 7 days after a single immunization with the extract was probably nonspecific, since bacillus Calmette-Guérin gave similar results. However, after three vaccinations, active cross-protection was observed, mainly against the strains of groups B and C, for at least 35 days after the last injection. In the mouse bacteremia model, the extract had a protective effect mainly against the homologous group Y strain but in a few experiments a significant protection was also obtained against the strains of groups A and B. The microbactericidal test revealed that even after three injections of mice, guinea pigs, or humans with the extract only the homologous bactericidal activity was induced. Since there was no close correlation between the results obtained with the two animal models and also with the microbactericidal procedure, no definitive conclusion can be drawn on the protective potential of our extract.
Growth of Legionella pneumophila in defined media: requirement for magnesium and potassium
Authors: Tesh Martha J. , Miller Richard D.
Published: May 2010

The inorganic ions magnesium and potassium were required for optimal growth of Legionella pneumophila in a chemically defined medium composed of amino acids and inorganic salts. Optimum growth was obtained at concentrations of approximately 20 μg/mL (80 μM) MgSO4∙7H2O and 150 μg/mL (2 mM) KCl. Comparable results were obtained with all six serogroups of L. pneumophila as well as with both laboratory-adapted and animal-passed strains.
The association of the surface array and the outer membrane of Deinococcus radiodurans
Authors: Thompson B. G. , Murray R. G. E. , Boyce J. F.
Published: May 2010

The hexagonal surface array of Deinococcus radiodurans strain Sark exhibits remarkably strong bonding of its subunits and association with the outer membrane. The array is not dissociated nor is it separated from the outer membrane by reagents that disrupt hydrogen bonds (urea, guanidine hydrochloride), ionic bonds (pH, LiCl, KCl, NaCl), disulphide bonds (β-mercaptoethanol, dithiothreitol), or chelating agents (ethylenediaminetetraacetic acid). Only disruption of the outer membrane with sodium dodecyl sulphate at room temperature separated the two layers. The isolated array was composed of a major protein of 115 000 molecular weight, a minor protein of 108 000 molecular weight, and no other polymers. Their amino acid profile was indicative of a protein, lacking proline, with a high proportion (51.2%, mole/mole) of polar amino acids. The electron-transparent layer between the hexagonal surface array and the outer membrane was still associated with the purified array, suggesting that the electron-transparent "layer" is a component of the protein array and impenetrable to stains so that the reactive groups are inaccessible. The observations suggest that hydrophobic amino acids make up a major domain of the array molecule and that nonspecific hydrophobic interactions are a large component of the forces involved in the tight association of the array within itself and with the underlying outer membrane. The surface of a mutant lacking the hexagonal surface array was compared with the surface of the wild type that possesses the hexagonal surface array using the two-phase droplet system of Schürch et al. (1981. Biochim. Biophys. Acta, 640: 557–571) to estimate the relative surface hydration. The contact angle for the mutant lacking the array was 128.8 ± 0.8 (SEM), n = 39, and the contact angle for the wild type was 92.6 ± 1.4 (SEM), n = 39, indicating that the surface of the outer membrane is relatively more hydrophobic than the outer aspect of the hexagonal surface array.
Effect of strain and medium variation on mosquito toxin production by Bacillus thuringiensis var. israelensis
Authors: Smith Robert A.
Published: May 2010

The effect of strain variation and culture medium on production of toxin lethal to mosquito larvae by Bacillus thuringiensis var. israelensis serotype H-14 was investigated. Shake flask culture of B. thuringiensis H-14 strains showed varied ability to produce toxins lethal to mosquito larvae dependent upon the particular strain and growth medium used. Buffered media demonstrated no better mosquito toxicity than did unbuffered media that ranged in pH from 5.7 to 8.1 at harvest. Although toxin production is associated with sporulation, spore count was generally not proportional to toxin produced for those strains and media evaluated.
Bacteriostatic action of nitrification inhibitors
Authors: Rodgers G. Alan , Ashworth John
Published: May 2010

Nitrification inhibitors were investigated in an attempt to establish whether such chemicals actually kill ammonium-oxidizing bacteria (bactericidal action) or whether bacteria remain viable but temporarily incapable of nitrification (bacteriostatic action). In laboratory experiments with nitrifying cultures, nitrification was completely inhibited, but numbers of ammonium-oxidizing bacteria were not significantly affected by a 48-h treatment with 2,6-dimethylbenzoquinone, dicyandiamide, or potassium ethyl xanthate applied at the rate of 100 mg inhibitor/L culture medium or by nitrapyrin at 10 mg/L. However, commercial formulations of etridiazole at 100 mg/L and nitrapyrin at 100 mg/L were apparently fatal to ammonium-oxidizing bacteria. In laboratory experiments with soil amended with nitrapyrin or etridiazole, both inhibitors were more bactericidal than in aqueous culture. Nitrification did not resume until 4 to 5 weeks after adding 0.5 mg inhibitor/kg soil and, especially with etridiazole, the population of ammonium oxidizers was drastically diminished and did not fully recover. However, in field experiments, nitrapyrin and etridiazole injected at 1.5 kg/ha with aqueous urea did not affect numbers of ammonium-oxidizing bacteria in cross-sections of the injected band of soil taken after injection in autumn or spring, although the inhibitors were present in concentrations that effectively inhibited nitrification.
Effect of the carbon source and cyclic AMP on isocitrate dehydrogenase, succinate dehydrogenase, and malate dehydrogenase in Klebsiella pneumoniae C3
Authors: Juarez A. , Parés R. , Vives-Rego J.
Published: May 2010

When strain C3 of Klebsiella pneumoniae is grown on a minimal medium with excess glucose, isocitrate dehydrogenase, malate dehydrogenase, and succinate dehydrogenase specific activities increase in the last period of the exponential growth phase and in the beginning of the stationary phase. Glucose exhaustion does not alter the development of malate dehydrogenase and succinate dehydrogenase, but specific activities are higher than those obtained with excess glucose. In contrast, glucose exhaustion can be correlated with a decrease of isocitrate dehydrogenase specific activity in the stationary phase. Induction of strain C3 isocitrate dehydrogenase by glucose in complex medium and repression by cAMP in mineral medium were observed. Glucose induction and the NADP/NADPH ratio are suggested as regulatory mechanisms controlling isocitrate dehydrogenase synthesis in the Enterobacteriaceae, but the former appears to be restricted to some Klebsiella strains.
Characterization of the total extractable lipids of Zymomonas mobilis var. mobilis
Authors: Tornabene T. G. , Holzer G. , Bittner A. S. , Grohmann K.
Published: May 2010

The cells of Zymomonas mobilis var. mobilis contained 6.3% of the chloroform–methanol–water extractable lipids (dry weight basis) and 1.5% of bound lipids. The extractable lipids were 96.8% polar lipids and 3.2% neutral lipids. The neutral lipids contained squalene, and 21 pentacyclic triterpene hydrocarbons comprised 1.4% of the total lipids. The remaining neutral lipids consisted of relatively small quantities of components tentatively identified as free fatty acids, tri-, di-, and mono-glycerides, lipoamino compounds, and pigments. The polar lipids consisted of methanol-soluble and -insoluble fractions. The methanol-soluble fraction consisted of phosphatidylethanolamine as the principal lipid and lysophosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, dimethylphosphatidylethanolamine, and phosphatide acid as the minor lipids. The methanol-insoluble fraction consisted of glycolipoproteins comprising glucosamine, galactosamine, myristic acid, and amino acids. This glycolipoprotein fraction differed from the material isolated by standard procedures for extracting lipopolysaccharides. The lipopolysaccharide fraction, in turn, was distinctly different from the lipopolysaccharides of other Gram-negative species, since deoxyhexoses, pentoses, hexoses, aminopentose, uronic acid, phosphate, and myristic acid were the principal constitutents. There was no evidence for ketodeoxyoctulonic acid, heptoses, or hydroxy fatty acids. Hexosamines were detected in trace amounts only by colorimetric analysis.
A comparison of the effects of several antifungal imidazole derivatives and polyenes on Candida albicans: an ultrastructural study by scanning electron microscopy
Authors: Bastide M. , Jouvert S. , Bastide J.-M.
Published: May 2010

The early events in the interaction of two polyene (amphotericin B and nystatin) and five imidazole (clotrimazole, ketoconazole, miconazole, isoconazole, and econazole) antimycotics used at fungicidal concentrations with the surface of Candida albicans were studied by scanning electron microscopic examination of treated intact young yeast cells, treated spheroplasts, and spheroplasts liberated from treated young yeast cells. In all cases, treatment lasted 2 h. The polyenes passed through the yeast cell wall and interacted with the cytoplasmic membrane causing the spheroplasts to lose their characteristic spheric form and to liberate their contents. Clotrimazole caused the formation of numerous circular openings in the cytoplasmic membrane, but only when the agent was used to treat spheroplasts directly. Ketoconazole, miconazole, isoconazole, and econazole interacted with the cell wall causing formation of convolutions and wrinkles. The three imidazole derivatives that are structurally closely related, miconazole, isoconazole, and econazole, inhibited the enzyme-catalyzed release of spheroplasts from young yeast cells.
Complement fixation by antibodies to the alpha toxin of Staphylococcus aureus
Authors: Lo Ching Y. , Fackrell Hugh B. , Barei Gary M.
Published: May 2010

When rabbits were injected with the heat-denatured alpha toxin (toxoid) of Staphylococcus aureus, the immune response was demonstrated by an increase in antitoxin that fixed complement. Such antitoxin was detected in 72% of normal human sera. After fractionation of the antitoxin into two types (the antibinding antibodies and the indirect hemagglutinating antibodies), both types of antibodies were found to fix complement in the standard serological complement fixation test. In addition, the indirect hemagglutinating antibodies were capable of fixing complement when the antigen (alpha toxin or toxoid) was covalently or noncovalently bound to erythrocyte membranes. The fixation of complement by membrane-bound immune complexes did not result in lysis of the carrier erythrocytes. The prevalence of complement-fixing antitoxin in normal humans and animals raised the concern that the outcome of in vivo experiments involving alpha toxin could be influenced by the immune status of the host.
Molybdenum enhancement of nitrogen fixation in a Mo-starved Azotobacter vinelandii Nif− mutant
Authors: Page William J. , Collinson S. Karen
Published: May 2010

Molybdenum (Mo)-starved wild-type and Nif− strains of Azotobacter vinelandii reduced acetylene (fixed nitrogen) in Mo-limited nitrogen-free medium. Vanadate enhanced this activity in all of the strains. Molybdate caused repression of nitrogenase activity in the Nif− mutants and enhanced the nitrogenase activity in the wild type. The nitrogenase activity in the Nif− mutant UW3, however, was enhanced by Mo, became maximal after 3 h, and then declined to zero after 10 h of incubation. The activation of nitrogenase by Mo followed a 5- to 10-min lag and was inhibited when streptomycin or rifampin was added with Mo. Examination of Mo-starved nitrogen-fixing UW3 cell extracts by two-dimensional polyacrylamide gel electrophoresis revealed molecular weight 57 000, 50 000, and 30 000 proteins that were Mo and NH4+ repressive. The molecular weight 30 000 protein appeared in the same position on the gel as the wild-type dinitrogenase reductase, although UW3 did not produce this protein under Mo-sufficient nitrogen-fixing conditions. Cell extracts prepared 3 h after Mo addition lacked the molecular weight 57 000 and 50 000 proteins but contained a new protein corresponding to the β subunit of dinitrogenase. When UW3 nitrogenase activity was lost, the dinitrogenase reductase-like protein also was absent. The results suggest that a complex active in nitrogen fixation may form between components of the traditional Mo-sufficient and alternative Mo-starved cell nitrogen fixation systems.
Étude ultrastructurale des bactéries présentes dans différents tissus de certains saumons femelles d'élevage qui présentent des anomalies dans leur reproduction
Authors: Hamon Claude
Published: May 2010

The coho salmon which can be bred in Brittany (France) grows normally but does not reproduce either because the females do not lay eggs or because most of the laid eggs do not develop. A corynebacterium is believed to be the cause of the abnormalities. In most of the animals studied, abcesses with bacteria like the Gram-positive type are found in the kidney, heart, and muscle. The ultrastructural study of these bacteria shows their original features. Liver, ovary, ovocytes, and hypophysis are not infected. If a relation exists between the bacterial infection and the abnormalities of female reproduction, it is certainly very indirect.
Reaction of an ascomycetous yeast with diazonium blue B
Authors: Lachance Marc-André
Published: May 2010

The new ascosporogenous yeast species Sporopachydermia quercuum has been found to react positively with the diazonium blue B reagent, a feature normally associated exclusively with yeasts of basidiomycetous affinity.
Colonization of tissue surfaces in the gastrointestinal tract of gnotobiotic animals by lactobacillus strains
Authors: Tannock G. W. , Szylit O. , Duval Y. , Raibaud P.
Published: May 2010

Eight strains of lactobacilli isolated from conventional mice, rats, fowls, and pigs were tested for their ability to colonize squamous epithelia in the gastrointestinal tracts of gnotobiotic animals. Two of the strains isolated from rodents could colonize the nonsecretory epithelium of the stomach of gnotobiotic rodents, and one strain isolated from a fowl could colonize the crop epithelium of gnotobiotic chickens. The specificity of colonization of squamous epithelia by lactobacilli was demonstrated by these in vivo studies: strains of lactobacilli isolated from rodents could only colonize rodent epithelium; the strain from a fowl could only colonize crop epithelium.
Asexual developmental markers in an aflatoxigenic strain of Aspergillus parasiticus
Authors: Batt Carl , Solberg Myron
Published: May 2010

The relationships between specific asexual development stages of Aspergillus parasiticus and potential enzyme markers of these stages were established. Competence was reached when culture age was 22.6 h for an initial inoculum level of 3.0 × 102 conidia∙mL−1 and 8.09 h for an initial inoculum level of 2.0 × 104 conidia∙mL−1. The appearance of laccase activity was correlated with the development of conidia. Laccase activity was detected only in conidiating cultures. Activity was inhibited in shaking cultures due to inhibition of conidiation. Laccase activity reached a maximum in cultures after 120 h. Inducible nitrate reductase activity was detected in A. parasiticus cultures after competence was established.
Occurrence of Vibrio parahaemolyticus in selected marine invertebrates, sediment, and seawater around Alexandria, Egypt
Authors: El-Sahn M. A. , El-Banna A. A. , Shehata A. M. El-Tabey
Published: May 2010

Samples of seawater, sediment, and the following invertebrates were collected from the Mediterranean Sea in the neighborhood of Alexandria, Egypt: sea urchins (Echinus spp.), clams (Tapes spp.), and wedge shells (Donax trunculus). A total of 165 samples were collected from November 1979 to July 1980. Average counts (per 100 mL or 100 g) of Vibrio parahaemolyticus content were as follows: seawater, 36; sea urchins, 349; sediment, 436; wedge shells, 534; clams, 1872. Samples collected in the summer months contained higher levels of V. parahaemolyticus than winter samples.
Sexual pheromone accumulation and response in agar plate and liquid cultures of Dictyostelium discoideum
Authors: Morris Paul S. , Lewis Keith E. , O'Day Danton H.
Published: May 2010

Sexual development in the mated cultures of Dictyostelium discoideum is initiated by one or more pheromones. In agar plate cultures of NC4, the presence of the pheromone becomes detectable by 22 h and reaches its maximal activity by 24 h. Cells of V12 from plate cultures also reach their maximal responsiveness at 24 h. In liquid culture, the NC4 pheromonal activity is detectable by 10 h and increases to a maximum at 15 h before declining so that by 30 h no activity is detectable. The V12 cells develop the competence to respond to the pheromone by 10 h and increase to a peak responsiveness by 15 h after which they lose the ability to respond. These data support earlier experiments demonstrating that sexual pheromones exist in the cellular slime moulds. The results of the liquid culture experiments in which the pheromonal induction of macrocyst formation reaches levels equivalent to 30% of mated cultures (NC4 × V12) also suggest that this pheromone bioassay system is sensitive enough to permit the isolation and characterization of the sexual pheromones of D. discoideum.
Relationship between synthesis of ribosomes and RNA polymerase in Bacillus subtilis
Authors: Leduc Eugene , Hoekstra Merl , Spiegelman George B.
Published: May 2010

The relationship between RNA polymerase synthesis and ribosome synthesis has been investigated in Bacillus subtilis growing at different rates. The amount of polymerase was determined by quantitation of polymerase subunits on polyacrylamide gels, while ribosome synthesis was estimated from accumulation of total RNA. The ratio of ribosome to RNA polymerase synthesis was 5:1 at slower growth rates and increased with growth rate. Bacillus subtilis was estimated to contain between 10-and 2-fold excess of RNA polymerase depending on its growth rate.
Comparison of the genomic arrangement and the relative transcription of the nitrogenase genes in Rhizobium meliloti during symbiotic development in alfalfa root nodules
Authors: Paau Alan S. , Brill Winston J.
Published: May 2010

In the course of the symbiotic development of free-living rhizobia to mature bacteroids in alfalfa nodules, mRNA transcripts of the nitrogenase structural genes are first detected when the rhizobia are inside the infection threads. These transcripts are most abundant in the mature bacteroids of young (6 to 8 weeks) root nodules and are present in a much lower level in bacteroids from senescent root nodules (13 weeks). Translation of these and related rhizobial genes essential for the symbiotic association apparently occurs very early in the symbiosis because the protein pattern of the "infection thread rhizobia" is very similar to that of the mature bacteroids and is different from that of the cultured vegetative rhizobia. Although bacteroids have a higher DNA content than the vegetative bacteria and are very different in the nucleoid organization, no specific amplification or rearrangement of the nitrogenase genes is detected in bacteroids.
Production of kojic acid by resuspended mycelia of Aspergillus flavus
Authors: Bajpai Pratima , Agrawala P. K. , Vishwanathan L.
Published: May 2010

Efforts have been made to develop a simple chemically defined resuspended mycelial system which may be used for carrying out fundamental studies regarding the mechanism of kojic acid biosynthesis. As a first step, it was found that mycelia grown in yeast extract sucrose (YES) medium and resuspended in YES medium or in 0.2 M phosphate buffer, pH 6.5, supplemented with 20% glucose or sucrose produced kojic acid almost to the same extent as in the case of growth medium. No kojic acid was formed if buffers or media used for resuspension lacked carbohydrate. Intact mycelia preincubated in buffer alone for 7 days and 3-week-old mycelia could still form kojic acid in large amounts if resuspended in buffer containing glucose. The amount of kojic acid produced by the intact mycelia was found to be more than that produced by the disrupted mycelia. In contrast with static resuspension studies, when Aspergillus flavus mycelia were resuspended in flasks placed on a rotary shaker, much smaller amounts of kojic acid were synthesized.
Survey of lipids of a new group of extremely halophilic bacteria from salt ponds in Spain
Authors: Kushwaha S. C. , Juez-Pérez G. , Rodriguez-Valera F. , Kates M. , Kushner D. J.
Published: May 2010

The lipids of eight strains of a new group of extreme halophiles isolated from Spanish salt ponds have been studied in comparison with those of Halobacterium cutirubrum, H. halobium, H. salinarium, H. marismortui, H. saccharovorum, and H. vallismortis. All strains showed the presence of C30 isoprenoids (squalene, dihydrosqualene, and tetrahydrosqualene), C40 carotenes (β-carotene), C50 pigments (bacterioruberins), and vitamin MK-8. All polar lipids were derivatives of 2,3-di-O-phytanyl-sn-glycerol. Diphytanyl glycerol ether analogues of phosphatidyglycerol and phosphatidylglycerophosphate were also present in all the strains but sulfated glycolipids were found in only six strains: two had a sulfated tetraglycosyl diether, a sulfated triglycosyl diether, and possibly a sulfated diglycosyl diether, whereas the other four had only sulfated diglycosyl diether. All strains contained diglycosyl diphytanyl diether. Significantly large amounts of the diphytanyl glycerol ether analogue of phosphatidylglycerosulfate were present in four strains. Strain R-4 exhibited marked changes in contents of individual pigments, but not in total lipids, when grown in different salt concentrations. Thus, in 15% salt it produced 18- to 19-fold more bacterioruberin than when grown in 25 or 35% salt. Similar reductions in the amounts of other C50 pigments and β-carotene were also observed. No significant changes in the contents of squalenes and vitamin MK-8 were observed. In contrast, H. cutirubrum produced C50 pigments and β-carotene only when grown in salt concentrations greater than 15%. Possible ecological consequences of the changes in pigmentation with salt concentration are discussed.
Immunosuppression, nonspecific B-cell activation, and mitogenic activity associated with a high molecular weight component from Listeria monocytogenes
Authors: Otokunefor T. V. , Galsworthy S. B.
Published: May 2010

A high molecular weight component of a saline extract derived from Listeria monocytogenes contained amino acids, carbohydrates, and phosphorus. The same fraction was capable of promoting both the in vitro mitogenic and adjuvant activities and the in vivo immunosuppressive activity displayed by the crude extract. The material was mitogenic to B but not to T lymphocytes in vitro. Responses to sheep and horse erythrocytes as well as to lipopolysaccharide were suppressed. Immunosuppression was dose dependent and was present at 1, 2, or 3 days but absent 7 days after injection. Both primary and secondary responses to sheep erythrocytes were impaired.
Isoenzymes of chloroperoxidase from Caldariomyces fumago
Authors: Pickard Michael A. , Hashimoto Atsumi
Published: May 2010

Chloroperoxidase (EC 1.11.1.10) was purified from Caldaromyces fumago strains ATCC 16373 and CM1 89362 grown in defined and complex media. Analysis of the enzyme by polyacrylamide gel electrophoresis at pH 3, sodium dodecyl sulfate – polyacrylamide gel electrophoresis, and isoelectric focussing in polyacrylamide gels revealed two forms of the enzyme, the major form representing greater than 80% of the total protein. When the fungi were grown in synthetic media, more of the enzyme was found in the major band than when the fungi were grown in the presence of malt extract. Enzyme activity was demonstrated both by staining gels in situ with 3,3′,5,5′-tetramethylbenzidine and by spectrophometric assay of material eluted from gel slices. There were no obvious differences between the enzyme from C. fumago ATCC 16373 and from C. fumago CMI 89362. Commercial samples, included for comparative purposes, contained three or four enzymically active species which separated on polyacrylamide gel electrophoresis at pH 3 and electrofocussing but migrated as a close double band on sodium dodecyl sulfate – polyacrylamide gel electrophoresis. It is believed that prolonged storage in the unfrozen state is responsible for the conversion to multiple forms.
Intracellular adenosine triphosphate and cyclic adenosine 3′,5′-monophosphate concentrations during derepression of actinomycin biosynthesis
Authors: Chatterjee S. , Vining L. C.
Published: May 2010

Measurements of adenosine triphosphate and of cyclic adenosine 3′,5′-monophosphate in the mycelium of Streptomyces antibioticus during growth in a medium containing a mixture of glucose and galactose showed no marked changes in concentration during the period when glucose was exhausted and the synthesis of actinomycin began. Thus, these nucleotides do not appear to have a role in mediating catabolite repression of either carbon source utilization or antibiotic production in this organism. Since no NADP-glucohydrolase activity was detected in cell extracts, this enzyme is also excluded from apossible role in regulating actinomycin biosynthesis.
Obligate methylotrophy: evaluation of methyl formate as a C1 compound
Authors: Meyers Jr. A. J.
Published: May 2010

Methyl formate, a C1 compound reportedly utilized by obligate methylotrophs, gave growth for Methylococcus capsulatus (Texas) but not for Methylosinus trichosporium (OB3b). Both organisms grew on methane, but only M. capsulatus (Texas) utilized methanol; neither organism could use formate as the sole carbon–energy source. Studies with M. capsulatus (Texas) showed that its growth rate on methyl formate was much slower than on methane or methanol, regardless of whether the cells were methane, methanol, or methyl formate grown. Methyl formate underwent "spontaneous" hydrolysis in uninoculated growth medium to yield formic acid and methanol, the latter serving as the actual growth substrate for M. capsulatus (Texas).
Intrafungal distribution of aflatoxins among conidia and sclerotia of Aspergillus flavus and Aspergillus parasiticus
Authors: Wicklow D. T. , Shotwell O. L.
Published: May 2010

This research examines the distribution of aflatoxins among conidia and sclerotia of toxigenic strains of Aspergillus flavus Link and Aspergillus parasiticus Speare cultured on Czapek agar (21 days, 28 °C). Total aflatoxin levels in conidia and sclerotia varied considerably both within (intrafungal) and among strains. Aspergillus flavus NRRL 6554 accumulated the highest levels of aflatoxin (conidia: B1 84 000 ppb; G1; 566 000 ppb; sclerotia: B1, 135 000 ppb; G1, 968 000 ppb). Substantial aflatoxin levels in conidia could place at risk those agricultural workers exposed to dust containing large numbers of A. flavus conidia. Cellular ratios of aflatoxin B1 to aflatoxin G1 were nearly identical in conidia and sclerotia even though levels of total aflatoxins in these propagule types may have differed greatly. Aflatoxin G1 was detected in sclerotia of all A. flavus strains but in the conidia of only one strain. Each of the A. parasiticus strains examined accumulated aflatoxin G1 in both sclerotia and conidia. These results are examined in the context of current evolutionary theory predicting an increase in the chemical defense systems of fungal sclerotia, propagules critical to the survival of these organisms.
Detection of Gardnerella vaginalis on vaginal smears by immunofluorescence
Authors: Cano Raul J. , Beck Melinda A. , Grady David V.
Published: May 2010

An indirect fluorescence antibody (IFA) test was developed for the detection of Gardnerella vaginalis. Antisera were prepared in rabbits by using five strains of G. vaginalis. A pool of the antisera was tested for specificity with a variety of isolates known to colonize the human vagina and (or) morphologically resemble G. vaginalis. Six heterologous bacterial isolates reacted with the pooled antiserum at dilutions of 1:10, but none reacted at the working dilution of 1:200. Vaginal swab specimens were collected from symptomatic and asymptomatic patients in order to further evaluate the IFA procedure. The presence of G. vaginalis in the specimens was determined both by culture and by the IFA procedure. Absorbed antisera reacted with all isolates of G. vaginalis tested. In a clinical trial the IFA procedure detected the presence of G. vaginalis in smears from 23 (24.2%) of the patients with nonspecific vaginitis (NSV), from 22 (29.8%) of the asymptomatic individuals tested, and from 3 patients with vaginitis other than NSV. The presence of G. vaginalis in smears as detected by the IFA procedure was confirmed by cultures in all cases using Vaginalis agar supplemented with colistin and nalidixic acid (V-CNA). It is suggested that the IFA procedure may be of use in conjunction with V-CNA in epidemiological studies of the carriage and transmission of G. vaginalis in human populations. It appears that the IFA procedure, at least in our hands, is a useful test for the rapid detection of G. vaginalis even when this microorganism is not the predominant colonizer of the human vagina.
Linkage mapping of Rhizobium japonicum D211 by phage M-l mediated transduction
Authors: Shah Ketan , Patel Chandrashekhar , Modi V. V.
Published: May 2010

Generalized transduction in Rhizobium japonicum D211 by phage M-1 was observed. Cotransduction frequencies of str-kan and str-rif were increased by ultraviolet irradiation of phage lysates. The order of different genetic markers was determined by transduction crosses. A linkage map of R. japonicum is constructed on the basis of cotransduction analysis.
An improved method for the preparation of mycobacterial spheroplasts and the mechanism involved in the reversion to bacillary form: electron microscopic and physiological study
Authors: Udou Takezo , Ogawa Midori , Mizuguchi Yasuo
Published: May 2010

An efficient method is described for preparing spheroplasts and protoplasts by treating bacillary cells of Mycobacterium smegmatis with precise concentrations of L-glycine (followed by lysozyme). This improved procedure was widely applicable to many rapidly growing mycobacteria by selecting the concentrations of glycine suitable for the individual strains used. The process of reversion of spheroplasts to original bacillary form on solid and in liquid media, as revealed by electron microscopy, appeared to involve the formation of an internal elementary or initial body with subsequent budding from the spheroplast. The internal membrane systems appeared to function in the induction of initial bodies and in the maturation of elementary bodies to become dividing forms. Possible mechanisms involved in the development of bacilli from spheroplasts are discussed.
Rhizobium infection threads in root hairs of Glycine max (L.) Merr., Glycine soja Sieb. & Zucc, and Vigna unguiculata (L.) Walp.
Authors: Pueppke Steven G.
Published: May 2010

Eight lines of soybean (Glycine max), four of wild soybean (Glycine soja), and one cowpea (Vigna unguiculata) cultivar were inoculated with 18 Rhizobium strains. After 4 days, root hairs were examined for infection threads. Threads were produced by all hosts but exclusively in nodulating combinations. Only Rhizobium sp. strains 3G4b9a and 3G4b19 were inconsistent; they nodulated soybean and G. soja in some experiments, but rarely formed infection threads. Soybean and G. soja were indistinguishable in their interactions with rhizobia, as were lele soybean lines (genetically lack soybean lectin), Hardee soybean (contains the noduation-influencing genes Rj2 and Rj3), and several other soybean cultivars. Threads formed in cowpea with all of the R. japonicum strains and most Rhizobium sp. but not with R. lupini. Infection of all three host species occurred in portions of the primary root containing immature or no root hairs at the time of inoculation; proximal tissues having elongated root hairs lacked infection threads. Infected root hairs were short and commonly shaped like question marks. Threads usually branched and sometimes intertwined prior to elongation into the basal portion of root hairs.
Studies on pathogenic, immunogenic, and protective efficiency of fox rabies virus before and after adaptation to cell culture: application to vaccination against rabies
Authors: Blancou J. , Aubert M. F. A. , Andral L.
Published: May 2010

Rabies virus from the submandibular salivary gland of a naturally infected fox was adapted to growth in BHK-21 cells. The pathogenicity of the original isolate and the cell culture adapted virus were compared by the intramuscular and oral routes in mice and foxes. Animals surviving exposure were tested for serum rabies antibodies (immunogenic efficiency) and for their ability to survive a second challenge with rabies virus (protective efficiency). In mice, ratios between lethal and protective doses of the two strains via the oral or muscular route were similar. In foxes, however, pathogenic efficiency was modified after cell culture adaptation, although good immunogenic and protective efficiency was maintained. Inoculation via the oral route resulted in lethal infection with the wild-type strain and survival (with some subsequent immunity) with the cell-adapted strain. Via the intramuscular route, foxes given high doses of cell culture adapted virus survived whereas several foxes given lower doses died and virus could not be reisolated. It is concluded that safety testing of modified strains should be done with different dilutions of virus in the target species. "Autosterilizing" infections may result in erroneous diagnosis.
An enation system for the isolation of Antarctic yeasts inhibited by conventional media
Authors: Vishniac H. S.
Published: May 2010

Yeasts peculiar to the Dry Valleys of Antarctica can be recovered by allowing them to become enate (grow out) from soil particles. The enation system was successful in liquid medium E-1 shaken at 160 rpm in a 10 °C water bath. Samples were spread on a richer medium, 2 MC. This system also allowed the isolation of typical soil yeasts from Colorado soils and of cyanobacteria, heterotrophic bacteria, filamentous fungi, and chlorophyta. Marked inhibitory effects of conventional yeast media account for the failure of previous investigators to isolate these Antarctic yeasts. Their abundance remains unknown, since E-1 and 2 MC also have some inhibitory effects.
Studies on experimental murine histoplasmosis: host protection and cellular immunity
Authors: Burt Wayne R. , Smith Randall A.
Published: May 2010

Mice immunized subcutaneously with 106 viable yeast cells of Histoplasma capsulatum exhibited host protection to a challenge infection and also exhibited concomitant manifestations of cellular immunity to a culture filtrate antigen (yeast extract dialysate (YED)-histoplasmin). Protective immunity was determined by quantitative culture of organisms from infected spleens on a solid medium containing a growth factor produced by the organism. As early as 4 days following immunization, host protection was observed in mice. Positive footpad swelling, indicative of delayed-type hypersensitivity, also was apparent at the early time period (4–7 days) after immunization. By days 14 and 21 following immunization, the mice exhibited maximum footpad responses and maximum splenic clearance of yeast cells. As an additional correlate of cellular immunity, YED-histoplasmin was coupled with chromic chloride to murine erythrocytes (M-RBC) and mixed with immune or nonimmune splenic lymphocytes to detect antigen-specific rosette forming cells (RFC's). Only splenic lymphocytes from mice immunized with H. capsulatum formed antigen-specific RFC's (≥ 0.2%). Pretreatment of splenic lymphocytes with antitheta (θ) serum plus complement greatly reduced the numbers of RFC's, illustrating their T cell nature. Host protection and cell-mediated immune responses decreased substantially by day 28 following immunization.
Fermentation of lactose by Bacteroides polypragmatus
Authors: Patel G. B.
Published: May 2010

Lactose fermentation by the mesophilic anaerobic bacterium Bacteroides polypragmatus was studied in 100-mL batch cultures using a mineral salts – vitamin medium containing 0.4% (w/v) yeast extract and cysteine-Na2S reducing agent. Bacteroides polypragmatus could be cultivated in the presence of initial lactose concentrations as high as 20.0% (w/v). However, at these levels, the lag period was approximately 12 h compared with less than 6 h in media containing up to 5.0% lactose. Optimum growth and substrate conversion to H2 was obtained in medium supplemented with 1.5–2.0% lactose. Under these growth conditions, the metabolic end products (moles per mole of lactose) after 48 h of incubation were 3.33 H2, 4.20 CO2, 1.82 ethanol, 1.46 acetic acid, and 0.06 butyric acid. The growth rate in approximately 2.0% (w/v) glucose or galactose medium (μ = 0.23 h−1) was higher than that (μ = 0.14 h−1) in lactose. The maximum rate of glucose and lactose utilization was 6.3 and 3.8 g∙L−1∙24 h−1, respectively. The maximum lactase in lactose-grown culture was about twice that of galactose-cultivated cells, and the activity in glucose culture was negligible. The results indicate that B. polypragmatus may be of potential use in the disposal of lactose, since besides H2, the cell biomass (approximately 35% cell protein) may also prove to be a useful by-product.
Serotypes of Neisseria meningitidis associated with an increased incidence of meningitis cases in the Hamilton area, Ontario, during 1978 and 1979
Authors: Ashton Fraser E. , Ryan J. Alan , Jones Colina , Brodeur Bernard R. , Diena Benito B.
Published: May 2010

The distribution of serotypes among strains of Neisseria meningitidis responsible for a marked increase of meningitis cases in the Hamilton area, Ontario, in 1978 and 1979 was determined. Twenty-six serogroup B and two serogroup W135 strains isolated from cerebrospinal fluid, blood, and skin of 28 patients were serotyped by agar gel double diffusion. Twenty-one (81 %) of the group B strains were serotype 2b as judged by the formation of characteristic serotype precipitin bands with the specific anti-2996 (type 2b) serum. Fourteen of the serotype 2b strains also reacted with anti-77252 serum, which suggested that one strain or several closely related strains were mainly responsible for the increase in meningitis during the 2-year period. Examination of the outer membrane complexes (OMC) of the strains by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS–PAGE) revealed that all 21 of the serotype 2b strains contained the class 2 protein (molecular weight 41 500) which is known to be the site of the serotype 2b determinant. Further characterization of the serotype 2b,77252 strains by enzyme-linked immunosorbent assays (ELISA) and SDS–PAGE suggested that the 77252 determinant was present in the class 1 proteins of these strains. The serotype 2b containing strains were isolated from 77.7 and 70% of males and females, respectively, from 81.8% of children less than 5 years of age, and from 75.0% of patients of all age groups. The study indicates the important role of serotype 2b meningococci in causing the increased incidence of meningitis and further substantiates the important association of the serotype 2b determinant with group B serotype 2 meningococcal disease in Canada.
Three new strains of infectious pancreatic necrosis virus isolated in Canada
Authors: Macdonald Richard D. , Moore Anne R. , Souter Brian W.
Published: May 2010

Three new samples of infectious pancreatic necrosis virus (IPNV) isolated in Canada were compared with known serotypes by phenotypic properties, immunofluorescence, and protein and RNA molecular weights. The three new isolates were each found to be unique by these parameters. The most convincing physical difference used to distinguish the new isolates from known serotypes was their RNA molecular weights. Thus, the new CB, NASRC, and Char isolates of IPNV represent three new strains of the virus.
Solubilization of the surface protein of Aquaspirillum serpens by chaotropic agents
Authors: Koval S. F. , Murray R. G. E.
Published: May 2010

The ability of chaotropic agents to solubilize the regularly structured (RS) protein from the outer membrane of Aquaspirillum serpens VHA was determined by electron microscopy and sodium dodecyl sulfate – polyacrylamide gel electrophoresis. The RS protein was not solubilized by cationic substitution, low pH, sodium deoxycholate, or some nonionic detergents. Some outer membrane proteins were solubilized along with the RS protein by octyl-β-D-glucopyranoside, sodium N-lauroyl sarcosinate, and zwitterionic detergents. Selective solubilization of the RS protein was achieved with lithium 3,5-diiodosalicylate.
The structure of the 5′ and 3′ ends of clover yellow mosaic virus RNA
Authors: AbouHaidar Mounir G.
Published: May 2010

The RNA of clover yellow mosaic virus (CYMV) contains a RNases-resistant oligonucleotide which was determined to be m7GpppGp and located at the 5′ end of RNA. This RNA also contains polyadenylic acid sequences of variable sizes (75–100 residues). These sequences were isolated by RNases T1 and A digestion, by binding to a poly(U)-Sepharose column, and by subsequent electrophoresis in 12% polyacrylamide gels in 7 M urea. The results of specific labelling of the 3′ -OH end of the RNA with 32PCP in the presence of RNA ligase and the ratio of radioactivity present in the poly(A) to that of the total RNA indicated that the poly(A) sequences are located at the 3′-OH end of CYMV-RNA.
β-Glucosidase excretion in Trichoderma strains with different cell wall bound β-1,3-glucanase activities
Authors: Kubicek Christian P.
Published: May 2010

Two different strains of Trichoderma pseudokoningii (SE1 A8 and SE1 D81) and Trichoderma viride QM 9123 release into the medium different proportions of the total β-glucosidase activity produced. This observation correlates with the degree of β-1,3-glucanase binding to the cell wall found for each strain. DEAE-Sephadex ion-exchange chromatography revealed three peaks of β-1,3-glucanase activity. These three enzymes (enzyme I, enzyme II, and enzyme III) differ in their extent of binding to the cell walls, their activity on isolated cell walls and Trichoderma β-glucan, and their affinity for β-glucan. Of these enzymes, enzyme II shows the largest variation in relative importance among the three strains and is located predominantly within the mural compartment. Enzyme II has the highest activity on and affinity for Trichoderma β-glucan. Enzyme II is also the most active in releasing β-glucosidase from cell walls of strain SE1 A8 (the strain excreting a high proportion of its β-glucosidase into the culture fluid) as well as from strain SE1 D81 (little β-glucosidase activity in the culture fluid). It is concluded that the action of β-1,3-glucanase II on cell wall β-glucan may be responsible for the in vivo release of cell wall bound β-glucosidase into the culture fluid.
Biochemical characterization of three mycobacterial ribosomal fractions
Authors: Portelance V. , Beaudet R.
Published: May 2010

The induction of antituberculous imunity by crude ribosomal fractions isolated from Mycobacterium tuberculosis strain H37Ra, M. bovis strain BCG, and M. smegmatis was studied in CF-1 mice. Levels of antituberculous immunity similar to that induced by live BCG were induced by the BCG and H37Ra ribosomal fractions whereas that isolated from M. smegmatis was found to be inactive. Electrophoresis of the three ribosomal fractions in sodium dodecyl sulfate – polyacylamide gels followed by differential staining showed the two active ribosomal fractions to be similar in their proteins, carbohydrate-containing substances, and lipid profiles. The inactive smegmatis ribosomal fraction differed mainly from the active ones on the basis of its carbohydrate-containing substances profile and by the absence of lipids. The polysaccharides and the ribosomes present in the H37Ra ribosomal fractions were purified by affinity chromatography on concanavalin A – Sepharose 4B. Each purified preparation showed no or only low antituberculous activity when injected separately, but when mixed together a high protection was observed. The formation of complexes between the ribosomes and the polysaccharide fraction was suggested and appears to be necessary for the induction of antituberculous immunity.
Strain-specific serological techniques for the identification of Rhizobium meliloti in commercial alfalfa inoculants
Authors: Olsen P. E. , Rice W. A. , Stemke G. W. , Page W. J.
Published: May 2010

Antisera were prepared against five Rhizobium meliloti strains including three strains adapted to Canadian soil and climate conditions and recently released for use in the production of commercial alfalfa (Medicago spp.) inoculants. The antisera were highly cross-reactive, but specificity was obtained by repeated massive adsorptions of the antisera with cells of the cross-reacting strains. The adsorbed antisera were used in microagglutination tests and the enzyme-linked immunosorbent assay (ELISA) to demonstrate the presence of the Canadian strains in their respective commercial peat-base inoculants at 108–109 viable cells/g. A plant infection technique which was also used to evaluate inoculant quality was specific only at the Rhizobium species level and required up to 4 weeks for completion. Serological techniques made it possible to identify and quantitate inoculant strains of R. meliloti while reducing the time required for testing. The agglutination analysis of inoculants was simple, but required regrowth of each colony isolate to generate sufficient cell numbers. The ELISA technique was used directly with colonies picked from plate counts, and the results were available within 5 days, including the time for colony growth on the plate media.