bluuebunny/crossref_metadata_2025 huggingface dataset:
Isolation and characterization of cellulolytic anaerobic fungi and associated mycoplasmas from the rumen of a steer fed a roughage diet
Authors: Kudo H. , Jakober K. D. , Phillippe R. C. , Cheng K.-J. , Barr D. J. S. , Costerton J. W.
Published: May 2010

The isolation of 12 strains of cellulolytic fungi from the rumen of a roughage-fed steer is described. These represented three different genera, including one new genus and species (Orpinomyces bovis). The organisms were indistinguishable on the basis of fermentation products from cellulose, and their fermentation patterns were very similar to those of rumen fungi isolated in other countries. Mycoplasmas were found to be associated with 7 of the 12 isolates. The ecological role of the association of the mycoplasmas with rumen fungi is still unknown. Key words: Orpinomyces bovis, Piromyces communis, Neocallimastix patriciarum.
Polymorphism in polydnavirus genomes
Authors: Stoltz Donald B. , Xu Deming
Published: May 2010

Polymorphisms were readily detected in polydnavirus DNA extracted from several different species belonging to two different families of parasitic hymenoptera. Heterogeneity was observed as differences in electrophoretic profiles of genome segments, differences in the number of cross-hybridizing genome segments, and restriction fragment length polymorphisms; polymorphism was also detected at the level of an individual genome segment. Some implications drawn from these observations are discussed. Key words: polydnavirus, multipartite genomes, DNA polymorphisms.
Degradation of phenol by a bacterial consortium under methanogenic conditions
Authors: Béchard G. , Bisaillon J.-G. , Beaudet R. , Sylvestre M.
Published: May 2010

An anaerobic bacterial consortium was shown to carboxylate phenol to benzoate under methanogenic conditions. Benzoate accumulated in the culture medium and was completely degraded when the incubation period was prolonged. Two potential intermediates of phenol metabolism, namely cyclohexanol and cyclohexanone, were not accumulated or transformed by the consortium. Proteose peptone must be added to the culture medium for the carboxylation of phenol to occur and glucose could not replace proteose peptone. Inhibition of methanogenesis did not affect the carboxylation of phenol and the presence or absence of hydrogen in the gaseous atmosphere did not prevent the accumulation of benzoate. The consortium was composed of various microbiological forms dominated by Gram-negative rods. Phenol-carboxylating microorganisms were evaluated to about ≥ 1 × 108 cells/mL by using diluted inocula. These results suggest that the carboxylation of phenol is accomplished by co-metabolism and that proteose peptone or some degradation products serve as carbon and energy sources for the growth of the carboxylating bacteria, which appear to be present in large numbers in the consortium. Key words: phenol, degradation, anaerobic, consortium, methanogenesis.
Esterase activity of pure cultures of rumen bacteria as expressed by the hydrolysis of p-nitrophenylpalmitate
Authors: Fay J. P. , Jakober K. D. , Cheng K.-J. , Costerton J. W.
Published: May 2010

Seventy-four strains of rumen bacteria comprising 20 genera were tested for the ability to hydrolyze p-nitrophenylpalmitate (PNPP-C16). This ability was detectable in all cultures tested, but the level of activity was quite variable. Known lipolytic strains of these bacteria showed generally low levels of activity in this assay, which suggests that the hydrolysis of this artificial substrate indicates a general esterase activity and not a lipase activity, as reported in the literature. The highest activity was found to occur in strains known to be feed-particle-associated digesters of starch, pectin and cellulose. In fractionated rumen contents, p-nitro-phenylpalmitase activity was largely associated with feed particles. Although the in vivo role of the enzymes that hydrolyze PNPP-C16 remains obscure, it appears that they are primarily of microbial origin, and may be important in hydrolyzing ester bond-containing compounds from plant material. Key words: Ruminobacter amylophilus, feed-particle association, lipolysis, cellulolytic bacteria, fractionated rumen content.
Regulation by amino acids of α-amylase and endo-β(1→4)-glucanase induction in mycelial culture of the mushroom Termitomyces clypeatus
Authors: Sengupta Saswati , Sengupta S.
Published: May 2010

Termitomyces clypeatus constitutively liberated amyloglucosidase; the liberation was not repressed by glucose. Growth of the mushroom in synthetic medium was slow with starch, and only amyloglucosidase was liberated. Yeast extract stimulated growth and enzyme production in starch medium, and α-amylase along with amyloglucosidase was detected extracellularly. The mushroom could not utilise cellulose or liberate endo-β(1 → 4)-glucanase even when inducer cellobiose or glucose was added to cellulose at different concentrations. Cellobiose alone also failed to induce any extracellular endo-β(1 → 4)-glucanase production. Yeast extract in both cellulose and cellobiose media supported liberation of endo-β(1 → 4)-glucanase. Lactose was found to be a poor inducer even in yeast extract medium. However, both α-amylase and endo-β(1 → 4)-glucanase were detected intracellularly at a basal level even when the enzymes were absent extracellularly under inducing and noninducing conditions. The intracellular enzymes were only freely liberated into the medium in the presence of yeast extract. It appeared that induction of α-amylase and endo-β(1 → 4)-glucanase was largely inhibited by the restricted liberation of the enzymes in absence of yeast extract. Of the yeast extract components, amino acids were the active ingredient mimicking the role of yeast extract in induction. Yeast extract was found to relieve catabolic inhibition observed at the late phase of enzyme production. It is proposed that catabolic inhibition might have a role in the enzyme liberation and that amino acids supported extracellular enzyme production by relieving this inhibition. Key words: mushroom, Termitomyces clypeatus, catabolic inhibition, polysaccharidase induction, amino acid.
Evidence for the glycoprotein nature of the cell sheath of Methanosaeta-like cells in the culture of Methanothrix soehngenii strain FE
Authors: Pellerin Patrice , Fournet Bernard , Debeire Philippe
Published: May 2010

The resilient of Methanothrix soehngenii strain FE was isolated. It contained carbohydrates (7%), mainly rhamnose, ribose, and fucose, which could be specifically liberated by alkaline hydrolysis or hydrazinolysis. Four oligosaccharide-containing fractions were separated; the two major fractions corresponded to large glycans composed of 15–30 residues. The whole sheath preparation was soluble in anhydrous hydrazine. A mild hydrazinolysis treatment led to a water-soluble glycoprotein fraction, which represented 60% of the starting material and contained 100% of the carbohydrates. These high molecular mass (> 500 kDa) glycoproteins were sensitive to pronase. Fast atom bombardment mass spectrometry analysis of the major glycopeptide fraction obtained after hydrogen fluoride treatment was in accordance with the presence of asparaginyl-rhamnose linkages on a Asn-X-Ser glycosylation site. This type of glycosidic linkage has been described previously in the surface layer of Bacillus stearothermophilus. Key words: Methanothrix soehngenii, Methanosaeta concilii, archaebacteria, bacterial glycoprotein, proteic sheath, asparaginyl-rhamnose.
Poly-β-hydroxybutyrate production in eight strains of the genus Acinetobacter
Authors: Vierkant Matthew A. , Martin Daniel W. , Stewart James R.
Published: May 2010

Since poly-β-hydroxybutyrate (PHB) inclusions have been reported in only a few strains of Acinetobacter grown on β-hydroxybutyrate, it was of interest to study comparatively the production of this lipid reserve in eight different acinetobacters. Three lines of evidence for PHB production were used: spectrophotometric analysis, infrared analysis, and electron microscopy. The spectrophotometric method showed that all eight strains produce PHB in stationary phase, the amounts ranging from 0.55 to 10.7 fmol/cell. PHB production was maximum after 1 h of growth in batch culture, with the amounts declining by 2 h and returning to near stationary phase cell levels in 4 h. Infrared spectra of purified PHB from the eight strains matched the spectrum of a commercial sample of PHB. In electron micrographs, the PHB reserves were visible as small electron-transparent bodies delineated by ultramembranes. PHB production in four strains (bath cultures) varied in response to exogenous glucose or xylose, with maximum production occurring over a range of 8–17 mM monosaccharide. Glucose was transported into cells by all strains in amounts that ranged from 0.5 to 1.6 fmol/cell, and 0.1–2.2% of that glucose was converted into PHB. Glucose transport was inhibited by cyanide. Key words: poly-β-hydroxybutyrate, acinetobacters.
Preliminary study on relationships among strains forming a bacterial community selected on naphthalene from a marine sediment
Authors: Tagger S. , Truffaut N. , Petit J. Le
Published: May 2010

Two bacterial strains were isolated from a bacterial community formed of nine strains, selected from a marine sediment on a seawater medium with naphthalene as sole carbon source. The two strains studied in the present work were the only strains of this community able to grow in pure culture on naphthalene; therefore, they were called "primary" strains. The seven other strains were maintained in the community by using metabolic intermediates of the two primary strains; they were called "auxiliary" strains. Regulation of naphthalene metabolism was studied for the two primary strains. They oxidized naphthalene into catechol, which was degraded only by the meta pathway. For Pseudomonas Lav. 4, naphthalene oxygenase and salicylate hydroxylase were inducible; catechol 2,3-dioxygenase was constitutive. For Moraxella Lav. 7, naphthalene oxygenase was constitutive; salicylate hydroxylase and catechol 2,3-oxygenase were inducible. The Moraxella strain carries two cryptic plasmids, about 63-and 85-kb in molecular size. In the bacterial community culture medium, Moraxella Lav. 7 prevented accumulation of 2-hydroxymuconate semialdehyde formed by Pseudomonas Lav. 4. The auxiliary strains take up formic, acetic, pyruvic, propionic, and succinic acids released by the two primary strains. Key words: marine bacterial community, naphthalene metabolism.
Petite colony formation by Listeria monocytogenes and Listeria species grown on esculin-containing agar
Authors: Siragusa Gregory R. , Elphingstone L. A. , Wiese P. L. , Haefner S. M. , Johnson M. G.
Published: May 2010

Several strains of Listeria species formed petite-sized colonies from parent stock cultures when grown on agar media containing 0.2 – 1% (w/v) esculin. This was observed in Listeria monocytogenes (7/22 strains), L. innocua (1/3), L. grayi (1/1), L. seeligeri (1/3), and L. welshimeri (1/1), but not in L. ivanovii (0/1) and L. murrayi (0/1). This phenomenon was only observed on agar media that contained esculin. All petite isolates had biotyping profiles identical to their larger, normal-sized counterpart isolates. Normal and petite-sized isolates from two L. monocytogenes strains, Scott A and V7, were pathogenic to immunosuppressed white mice. On media containing 0.5% (w/v) esculin + ferric iron, Listeria cultures produced colony diameters intermediate in size between those of normal and petite cultures. When pregrown in glucose broth, all petite isolates demonstrated visible β-glucosidase (esculinase) activity within 5 min, while the normal-sized isolates showed β-glucosidase activity only after at least 20–70 min. This evidence suggests that cells forming petite colonies are β-glucosidase constitutive variants within the parent population, while cells that form normal-sized colonies are inducible for β-glucosidase (esculinase) activity. A possible role for the esculin hydrolysis product, esculetin, in causing petite colony formation is discussed. Key words: Listeria species, petite colonies, esculinase, pathogenicity.
Expression of dibenzothiophene-degradative genes in two Pseudomonas species
Authors: Foght J. M. , Westlake D. W. S.
Published: May 2010

The genes encoding dibenzothiophene (DBT) degradation in Pseudomonas alcaligenes strain DBT2 were cloned into plasmid pC1 by other workers. This plasmid was conjugally transferred into a spontaneous variant of Pseudomonas sp. HL7b (designated HL7bR) incapable of oxidizing DBT (Dbt− phenotype). Acquisition of plasmid pC1 simultaneously restored oxidation of DBT and naphthalene to the transconjugant, although the primary DBT metabolite produced by transconjugant HL7bR(pC1) corresponded to that produced by wild-type strain DBT2 rather than that from wild-type strain HL7b. Inducers of the naphthalene pathway (naphthalene, salicylic acid, and 2-aminobenzoate) stimulated DBT oxidation in transconjugant HL7bR(pC1) when present at 0.1 mM concentrations but had no effect on wild-type strain HL7b. Higher concentrations (5 mM) of salicylic acid and naphthalene were inhibitory to DBT oxidation in all strains. DNA–DNA hybridization was not observed between plasmid pC1 and genomic DNA from strains HL7b or HL7bR, nor between authentic naphthalene-degradative genes (plasmid NAH2) and either plasmid pC1 or strain HL7b, despite the observation that the degradative genes encoded on plasmid pC1 functionally resembled broad-specificity naphthalene-degradative genes. Transconjugant HL7bR(pC1) is a mosaic of the parental types regarding DBT metabolite production, regulation, and use of carbon sources. Key words: dibenzothiophene, naphthalene, degradation, regulation, hybridization.
Detection of American foulbrood disease of the honeybee, using a monoclonal antibody specific to Bacillus larvae in an enzyme-linked immunosorbent assay
Authors: Olsen Perry E. , Grant Gordon A. , Nelson Donald L. , Rice Wendell A.
Published: May 2010

American foulbrood, a virulent disease of honeybees, is caused by Bacillus larvae. A murine hybridoma which secretes an IgM monoclonal antibody reactive with B. larvae was derived and an indirect enzyme-linked immunosorbent assay (ELISA) using this monoclonal antibody was evaluated for use in detection of the pathogen. The ELISA detected B. larvae strains from Alberta. and British Columbia, Canada, and from the United States but did not detect six other Bacillus species. The ELISA also detected the presence of B. larvae in field samples collected from commercial apiaries. Results of testing against cultures of B. larvae and infected bee larvae from hives indicate that the monoclonal antibody has, in conjunction with the indirect ELISA technique, potential for use in the diagnosis and confirmation of American foulbrood in commercial apiaries and in honeybee pathology research. Key words: American foulbrood, Bacillus larvae, honeybee disease.
Antituberculous drug susceptibility testing of Mycobacterium bovis BCG strain Montréal
Authors: Rousseau Paul , Dupuis Martine
Published: May 2010

Testing of Mycobacterium bovis BCG strain Montréal for susceptibility to four primary antituberculous drugs (isoniazid, ethambutol, streptomycin, and rifampin) and to one secondary drug (p-aminosalicylic acid) showed the strain to be susceptible to all five substances. Mycobacterium bovis strains ATCC 35735, which is isoniazid sensitive, and ATCC 35747, which is isoniazid resistant, were included in the test; with the exception of their respective susceptibility to isoniazid, both were inhibited by the other four drugs. Key words: BCG Montréal, drug susceptibility, cancer.
Physiology of biosurfactant synthesis by Rhodococcus species H13-A
Authors: Singer M. E. Vogt , Finnerty W. R.
Published: May 2010

The physiology of biosurfactant synthesis by a soil isolate, identified as a Rhodococcus species, is described. The biosurfactant is a surface-active glycolipid produced during the stationary growth phase of Rhodococcus species H13-A on n-alkanes and fatty alcohols in response to limiting ammonium ion concentrations. Hexadecane-grown cells produced increasing amounts of extracellular glycolipid when the carbon to nitrogen ratio (C/N) was increased from 1.7 to 3.4. The increase in extracellular glycolipid in hexadecane-grown cells correlated with a decrease in the interfacial tension of the spent growth medium to values less than 5 mN/m. Significant levels of extracellular glycolipid were not detected in the spent growth medium of cells grown on triglycerides, fatty acids, ethanol, organic acids, or carbohydrates. Rhodococcus species H13-A contains the three indigenous plasmids pMVS100, pMVS200, and pMVS300, with neither pMVS200 nor pMVS300 being involved in glycolipid synthesis or hexadecane dissimilation. The role of pMVS100 remains undetermined. Key words: biosurfactants, glycolipids, trehalose lipids, Rhodococcus.
Physical and chemical properties of a biosurfactant synthesized by Rhodococcus species H13-A
Authors: Singer M. E. Vogt , Finnerty W. R. , Tunelid A.
Published: May 2010

The chemical and physical properties of a biosurfactant synthesized by hexadecane-grown Rhodococcus species H13-A are described. The biosurfactant is an anionic glycolipid consisting of 1 major and 10 minor components. The hydrophilic portion of the molecule is trehalose, which is acylated with normal C10 to C22 saturated and unsaturated fatty acids, C35 to C40 mycolic acids, hexanedioic and dodecanedioic acids, and 10-methyl hexadecanoic and 10-methyl octadecanoic acids. The major glycolipid species was identified as 2,3,4,6,2′,3′,4′,6′-octaacyltrehalose, plus minor glycolipid species of di-, tetra- and hexa-acyltrehalose derivatives. The glycolipid exhibited a critical micelle concentration of 1.5 mg/mL and minimum interfacial tension value of 2 × 10−2 mN/m against decane, with a further reduction in interfacial tension to 6 × 10−5 mN/m in the presence of the cosurfactant pentanol. The phase behavior of the glycolipid indicates the formation of a surfactant-rich, "middle-phase" microemulsion containing liquid crystals, both of which are associated with surfactant systems having ultralow interfacial tension values. Key words: trehalose lipids, glycolipids, biosurfactants.
Persistence of introduced Bradyrhizobium japonicum strains in forming nodules in subsequent years after inoculation in Wisconsin soils
Authors: McLoughlin T. J. , Alt S. G. , Merlo P. A.
Published: May 2010

Nodulation of soybeans by indigenous and inoculum strains of Bradyrhizobium japonicum was studied in field experiments in Wisconsin from 1983 to 86. Aqueous suspensions of bacteria were applied to seeds at the time of planting at levels of 7 × 107–1010 bacteria per 2.5-cm row. The predominant indigenous serogroup was 123 in these soils. Six different inoculum strains were used (two from serocluster 123, two from serogroup 110, and one each from serogroups 122 and C1). Nodule occupants were identified using spontaneous antibiotic-resistant mutations in the inoculum strains, phage typing, and serotyping. In the 1983 experiment, the majority of nodules were formed by the inoculum strains in almost all cases (up to 100% in some cases), in two different soils containing 3.5 × 105 indigenous B. japonicum per gram. After 2 years without inoculation at the same two site, the inoculum strains did not form many nodules on uninoculated soybeans (less than 10% in most cases; less than 30% in all cases). In inoculation experiments carried out in 1985 and 1986, four inoculum strains were used (3 members of 123 serocluster and USDA 110str); inocula containing 108 bacteria per 2.5-cm row formed less than42%ofthe nodules in soils containing 1 × 104–4 × 104B. japonicum per gram. The major conclusions are (i) the success of inoculation in Midwestern U.S. soils is highly variable, even with members of the (highly competitive) 123 serocluster, and (ii) successful inoculation in 1 year in a Wisconsin soil does not ensure that the inoculated strain will persist in forming nodules in that field in subsequent years without further inoculation. Key words: Bradyrhizobium japonicum, strain persistence, field trials.
Two new mutant loci (smhB and lytD) in Escherichia coli which confer temperature-sensitive growth and lysis phenotypes
Authors: Dai Dexi , Ishiguro Edward E.
Published: May 2010

A temperature-sensitive mutation in the murH gene of Escherichia coli confers a lysis phenotype at the restrictive temperature. An extragenic suppressor of murH apparently representing a new locus at 12.5 min on the linkage map and designated smhB is described. The smhB mutation by itself also conferred a temperature-sensitive lysis phenotype. A mutation in another new locus designated lytD which arose spontaneously in the smhB mutant was mapped close to smhB at 12.7 min on the linkage map. The lytD mutation by itself conferred a temperature-sensitive lysis phenotype indistinguishable from that of the murH mutant. Thus, the suppression of lysis in the smhB murH and the smhB lytD double mutants suggests a mechanism involving the reciprocal suppression of the two individual lysis-causing mutant alleles. The suppressor activity of smhB was apparently relatively specific in that smhB failed to prevent lysis induced by either mutational (murE or murF) or antibiotic-induced blocks in peptidoglycan synthesis. This suggests that murH, smhB, and lytD may be functionally related. Key words: temperature-sensitive mutation, Escherichia coli, lysis phenotype, suppression.
Competition for nodule occupancy of introduced Bradyrhizobium japonicum strains in a Wisconsin soil with a low indigenous bradyrhizobia population
Authors: McLoughlin T. J. , Hearn S. , Alt S. G.
Published: May 2010

The population dynamics of six introduced Bradyrhizobium japonicum strains were measured over three growing seasons in a Wisconsin soil with a low incidence of indigenous B. japonicum (10 cells/gm). Four antibiotic-resistant members of the 123 serocluster (which were either spectinomycin resistant or streptomycin resistant), USDA 110, and USDA 138 were inoculated using liquid inoculum, at a rate of 1 × 108 cells per 2.5-cm row, on two soybean cultivars in 1985. Nodule occupants were identified using an enzyme-linked immunosorbent assay (ELISA), fluorescent antibodies, and antibiotic-resistant mutants. In the first growing season, 100% of the nodules were formed by the introduced strains. The nodules from the uninoculated plots were occupied by an indigenous 110 serogroup. In the second and the third season at the same site (without further inoculation), a high percentage (> 60%) of the nodules from all the plots were nodulated by the 123 serocluster (either alone or as mixed infections). However, < 25% of the nodules in the 123-inoculated plots and < 9% in the other plots were formed by any of the antibiotic-marked 123 inoculum strains introduced in 1985. The main conclusions are (i) that it is possible to successfully introduce inoculum strains in soils where the indigenous Bradyrhizobium population is low and to obtain 100% nodule occupancy in the first growing season, and (ii) that successful inoculation in one year in soils with a low incidence of Bradyrhizobium does not ensure that the introduced inoculum strains will form nodules in subsequent years. Key words: Bradyrhizobium japonicum, indigenous bradyrhizobia, interstrain competition, field trials.
Numerical taxonomic study of three N2-fixing yellow-pigmented bacteria related to Pseudomonas paucimobilis
Authors: Bally René , Givaudan Alain , Bernillon Jacques , Heulin Thierry , Balandreau Jacques , Bardin René
Published: May 2010

Three N2-fixing yellow bacteria (5AJ, 5ATR, and 29AJ) isolated from the rhizosphere of rice, previously found to be related to Flavobacterium capsulatum by DNA–rRNA hybridization, were compared on the basis of 115 morphological, physiological, biochemical, and nutritional characters. The bacteria were nonfermentative, irregular motile rods with polar flagella. They exhibited a gram-negative reaction and yellow pigmentation. A numerical analysis using these phenotypic characteristics showed that the bacteria were more closely related to Pseudomonas paucimobilis than to F. capsulatum. A relationship to the P. paucimobilis cluster was also supported by the presence of the pigment nostoxanthin. This pigment was also found in F. capsulatum and could be used as a distinctive marker for this group of yellow bacteria. Their phenotypic properties, protein patterns, and serological tests (ELISA) showed that two of the isolates (5AJ and 5ATR) were identical and had originated from the same parental strain. On the other hand, the serological tests indicated that both N2-fixing yellow bacteria (5AJ or 5ATR and 29AJ) differed from the reference strains, F. capsulatum and P. paucimobilis. Key words: N2-fixing bacteria, taxonomic study, nostoxanthin, Pseudomonas.
Host plant effect on competition among strains of Rhizobium leguminosarum
Authors: Hynes Michael F. , O'Connell Michael P.
Published: May 2010

Analysis of plasmid profiles was used to type Rhizobium leguminosarum biovar viciae strains isolated from nodules of peas, lentils and faba beans grown in two different soils. One soil was from a native pasture with no previous history of cultivation, the other was from a plot in a rotation study which included lentils every 2 years. The results indicated a strong preference of both peas and faba beans for strains having certain specific plasmid profiles. Strains belonging to one plasmid profile group (group 2) formed over half the nodules on peas grown in soil from the rotation plot but were never found on faba beans grown in the same soil, while strains from another group (group 5) formed nearly all of the nodules on faba beans grown in soil from the rotation plot, but no nodules on peas. Competitiveness for pea nodulation was correlated with an ability to catabolize homoserine, an amino acid found in large quantities in pea root exudate. Strains having plasmid profiles corresponding to those of strains that have been used in commercial inoculants over the last few years were isolated only rarely, regardless of the soil and host plant studied. Key words: Rhizobium, competition, plasmids, legumes, nodulation.
Interaction of the Bacillus sphaericus mosquito larvicidal proteins
Authors: Davidson Elizabeth W. , Oei Coreen , Meyer Marian , Bieber Allan L. , Hindley John , Berry Colin
Published: May 2010

Genes for 51.4- and 41.9-kDa insecticidal proteins of Bacillus sphaericus were separately cloned and expressed in Escherichia coli. Both proteins were required for toxicity. Approximately equal numbers of cells containing the 51.4- and 41.9-kDa proteins produced the greatest toxicity; excess 41.9-kDa protein did not affect toxicity, whereas excess 51.4-kDa protein reduced activity. Larvae were killed when 41.9-kDa protein was fed up to 24 h after the 51.4-kDa protein, but not when the order of feeding was reversed. Radiolabelled toxins bound in approximately equal amounts to the gastric caecum and posterior midgut of Culex quinquefasciatus larvae. Radiolabelled 51.4-kDa protein was rapidly degraded by ca. 12–13 kDa in the larval gut, while 41.9-kDa protein was degraded by 1–2 kDa. Nonreduced toxin extracted from B. sphaericus produced a band on SDS–PAGE of ca. 68–74 kDa that contained both 51.4- and 41.9-kDa proteins based on sequence analysis, and a band of ca. 51 kDa that contained primarily 41.9-kDa protein. Escherichia coli containing 51.4-kDa protein enhanced toxicity of the latter eluted SDS-PAGE band. These proteins may associate very strongly, and trace amounts of 51.4-kDa protein in preparations of 41.9-kDa protein from B. sphaericus may be responsible for the previously reported toxicity of the latter. Key words: Bacillus sphaericus, toxin, mosquito, cloning.
Protection against Klebsiella pneumoniae induced lobar pneumonia in rats with lipopolysaccharide and related antigens
Authors: Rani Mamta , Gupta Rajesh K. , Chhibber S.
Published: May 2010

The immunoprotective role of lipopolysaccharide and related antigens from Klebsiella pneumoniae was studied in a lobar pneumonia model developed in rats. Various antigens were obtained by different chemical treatments of the lipopolysaccharide. All these antigens (purified lipopolysaccharide, reduced lipopolysaccharide, lipopolysaccharide – bovine serum albumin complex, and lipid A – bovine serum albumin complex were tested for pyrogenicity and the Shwartzman reaction. The lipopolysaccharide and the various related antigens were pyrogenic and elicited a positive Shwartzman reaction at high concentrations. However, at low concentrations, the same preparations did not show any side effects. All these antigens, on the other hand, were protective against bacterial challenge in Klebsiella pneumoniae induced lobar pneumonia in rats, as the bacterial colonization of lungs in the immunized animals was significantly lower when compared with the controls. The alveolar macrophages from these animals also showed significantly more uptake of Klebsiella pneumoniae as compared with those obtained from control animals. Key words: lipopolysaccharide, vaccine, pneumonia, protection.
Fusion protein based epitope mapping of the MPB57 protein from Mycobacterium bovis BCG and its epitope insertion into the native protein
Authors: Yamaguchi Ryuji , Matsuo Kazuhiro , Yamazaki Akihiro , Kagawa Hiroaki , Nagai Sadamu , Yamada Takeshi
Published: May 2010

The gene coding for the 12-kDa protein (MPB57) of Mycobacterium bovis BCG has recently been cloned and sequenced (R. Yamaguchi, K. Matsuo, A. Yamazaki, S. Nagai, K. Terasaka, and T. Yamada. 1988. FEBS Lett. 240:115–117).To map linear B-cell epitopes by ß-galactosidase fusion proteins, we have constructed convenient vectors (pUR278S, pUR288S, and pUR289S) with the SmaI site. Based on recognition by polyclonal antibodies, two epitope regions on the MPB57 protein were identified, both of which corresponded to the amino acid sequences Glu20 to Val45 (26 residues, epitope I region) and Ile78 to Leu86 (9 residues, epitope II). Complementary oligonucleotides encoding epitope II were synthesized, polymerized by a ligase reaction, inserted into the native MPB57 protein gene, and expressed in Escherichia coli, giving rise to epitope-inserted proteins. Their stability and potential uses are described. Key words: epitope, fusion protein, repeat sequence, subunit vaccine.
Xylitol production by Petromyces albertensis grown on medium containing D-xylose
Authors: Dahiya Jagroop S.
Published: May 2010

Petromyces albertensis produced xylitol and D-xylulose when cultivated on a medium containing D-xylose. These fermentative products were identified by high-performance liquid chromatography. A large amount of xylitol was obtained from a D-xylose medium containing ammonium acetate and yeast extract at an initial pH of 7.0. Maximum production of xylitol and of the enzymes concerned with its production was observed after 10 days of cultivation. A D-xylose (100 g/L) medium supplemented with 1% (v/v) methanol gave the highest yields of xylitol (39.8 g/L) and D-xylulose (2.8 g/L). Key words: Petromyces albertensis, D-xylulose, xylitol.
Effect of nitrogen supply on rhizosphere interactions and take-all disease of wheat
Authors: Leggett M. E. , Sivasithamparam K. , McFarlane M. J.
Published: May 2010

The effect of NH4NO3 on the expression of take-all in wheat and on the ability of fluorescent pseudomonad bacteria to decrease the growth of the pathogen and the symptoms of the disease was examined in a nitrogen-deficient acidic soil from Western Australia. Application of NH4NO3 increased the fresh weight of shoots, decreased root weight and length, and offset some of the deleterious effects of infection. Inoculation with Gaeumannomyces graminis var. triciti reduced shoot weight and root weight and length at all but the highest level of applied nitrogen. Fluorescent pseudomonads applied to wheat seed (at approximately 108 colony-forming units/seed) reduced seed germination and failed to reduce the severity of take-all expressed as weight or length of shoots or N content. Although the density of black runner hyphae of G. graminis var. triciti was reduced at 40 days and the proportion of root colonized by the pathogen was lower at 28 days with bacterization under severe nitrogen deficiency, no effect of the bacteria was observed if N was added. Key words: Gaeumannomyces graminis var. triciti, fluorescent pseudomonads, wheat, nitrogen.
Variations spatio-temporelles de l'abondance et de la production du bactérioplancton dans un lac humique du Bouclier canadien
Authors: Letarte Yvon , Pinel-Alloul Bernadette
Published: May 2010

We followed the diel and summer variations of bacterioplankton production (estimated from [3H] thymidine incorporation) and abundance (direct count with 4′,6-diamidino-2-phenylindole staining) at four depths in a Canadian Shield humic lake. We found production to be highest and most variable in the epilimnion, but the differences between production estimates made at different times were statistically significant in only 5 out of 16 cases. Production differed significantly among depths in 14 out of 18 trials. The renewal time of the bacterial community varied between 1 and 20 days. Bacterioplankton production and primary production were uncorrelated (r = 0.225; p > 0.2), but bacterial production and chlorophyll a concentration were positively correlated (r = 0.816; p < 0.005). Small coccis (~0.3 – ~0.8 μm) represented between 52 and 80% of the bacterial cells in all the samples. There was no correspondence between bacterial production and frequency of dividing cells. Bacterial production and abundance varied inversely throughout the season, bacteria being two to three times less concentrated in the spring, whereas production was two to three times higher. We found no correlation between bacterioplankton production and abundance (r = 0.012; p > 0.5). Our results demonstrate the importance of small-scale sampling and the difficulty with which bacterioplankton production, its spatiotemporal variations, and the relationships between bacteria and phytoplankton can be predicted. Key words: bacterioplankton, abundance, production, spatiotemporal variations, bacterioplankton–phytoplankton relationships.
Acidiphilium symbioticum sp.nov., an acidophilic heterotrophic bacterium from Thiobacillus ferrooxidans cultures isolated from Indian mines
Authors: Bhattacharyya Saswati , Chakrabarty B. K. , Das A , Kundu P. N. , Banerjee P. C.
Published: May 2010

Two cultures of Thiobacillus ferrooxidans enriched from Indian mine samples and grown autotrophically on FeSO4 – basal salts medium for periods ranging from several months to years contained acidophilic, heterotrophic bacterial contaminants. The heterotrophs (strains KM2 and H8) were isolated by selective growth in a mineral salts – glucose – yeast extract medium of pH 3 and were purified as single colonies on an agarose medium. Mannose, galactose, sucrose, lactose, citrate, mannitol, and glycerol supported the growth of these strains in the presence of yeast extract. The heterotrophs grew poorly or failed to grow in media without yeast extract. They could not grow autotrophically with Fe2+, or with sulfur and its oxidizable derivatives, as the sole source of energy. Although they exhibited many characteristics of the genus Acidiphilium, they differed from Acidiphilium cryptum and other species of this genus in some physiological properties, notably in their ability to grow at higher glucose (5%, w/v) and Mn2+ (20 mM) concentrations. The G+C mol% contents (58.8 and 60.2) of strains KM2 and H8, respectively, determined from melting temperature (Tm) values were close to that of A. cryptum (62.7%). Strains KM2 and H8 showed 70–80% DNA homology with each other and about 60% with A. cryptum. All of the strains, including A. cryptum, responded similarly to several metal ions and antibiotics. SDS–PAGE of whole-cell proteins exhibited striking similarity between these two isolated strains, which were unlike that of A. cryptum. The strains were also agglutinated with a few common lectins and differed strongly from A. cryptum in respect to wheat-germ agglutinin and concanavalin A. Considering all these characteristics, we propose that strains KM2 and H8 be designated as a new species: Acidiphilium symbioticum. The type strain of A. symbioticum is strain KM2 (= MTCC 566). Key words: Acidiphilium symbioticum, Acidiphilium cryptum, Thiobacillus ferrooxidans, acidophilic bacteria.
Isolation and sequencing of a genomic DNA clone containing the 3′ terminus of the 6-methylsalicylic acid polyketide synthetase gene of Penicillium urticae
Authors: Wang Ing-Kae , Reeves C. , Gaucher G. M.
Published: May 2010

A 7.7-kilobase (kb) Penicillium urticae genomic DNA fragment containing the 3′ terminus of the 6-methylsalicylic acid polyketide synthetase gene was cloned using a 41-mer mixed oligodeoxynucleotide probe which was based on a cyanogen bromide cleavage peptide of 35 amino acids obtained from pure synthetase. Nucleotide sequence analysis of a 2.2-kb region of the cloned fragment revealed a large open reading frame of 1866 bases which was devoid of introns and which corresponded to amino acids of the carboxyl terminus of the enzyme. This was followed by a putative transcription termination–polyadenylation signal. A putative acyl carrier protein domain at the 3′ terminus was preceded by a β-ketoreductase domain. These functionalities were identified by amino acid sequences known to be characteristic of the active sites of fatty acid synthetase functional domains. Their relative positions contrast with those in yeast and P. urticae fatty acid synthetase genes where the two functional domains are located at the 5′ terminus and in reverse order. Furthermore, amino acid sequence identities indicated a striking homology with vertebrate rather than either yeast or P. urticae fatty acid synthetases. Key words: multifunctional enzyme, mycotoxin, Pencillium, polyketide synthetase, secondary metabolism.
Glucose transport by an arctic and a temperate strain of rhizobia
Authors: Bigwaneza Pierre C. , Prévost Danielle , Bordeleau Lucien M. , Antoun Hani
Published: May 2010

Glucose transport was studied in two strains of Rhizobium species effective on sainfoin (Onobrychis viciifolia), the arctic strain N31 isolated from Astragalus alpinus and the temperate strain SM2 isolated from sainfoin. The two strains had comparable glucose transport systems with a biphasic kinetics, indicating the presence of a high- and low-affinity transport system. Apparent Km and Vmax values for the high- and low-affinity transport systems were, respectively, 4.7 and 53.4 μM and 12.7 and 58.9 nmol∙min−1∙mg protein−1 with N31 and 2.6 and 72.6 μM and 10.1 and 64.6 nmol∙min−1∙mg protein−1 with SM2. Glucose transport systems were inhibited by 2,4-dinitrophenol, KCN, azide, and N-ethylmaleimide. NaF did not affect glucose transport, while arsenate showed partial inhibition of the low-affinity transport system with strain N31. These results suggest an active mechanism of transport that is dependent on an energized membrane but does not directly utilize high-energy phosphate compounds. In the two strains, glucose transport is constitutive and repressed by succinate, and it is glucose specific. Key words: Arctic, glucose, Rhizobium, symbiosis, transport.
Cobalt and sodium requirements for methanogenesis in washed cells of Methanosaeta concilii
Authors: Patel G. B. , Sprott G. D.
Published: May 2010

Methanosaeta concilii GP6 lost methanogenic activity upon thorough washing of the cells with an anaerobic buffer. Methane production from acetate could be restored by supplementing the washed cell suspension with spent growth medium, and to a lesser degree (65–70% of the rate obtained with spent medium) by the coaddition of NaCl and CoCl2. The latter reactivation had an apparent Km for CoCl2 of 5.6 μM in the presence of 40 mM NaCl, and an apparent Km for NaCl of 2.5 mM in the presence of 5 μM CoCl2. The requirement for NaCl could be met by LiCl but only partially by MgCl2, CaCl2, or NiCl2. Methylcobalamin could substitute for CoCl2. Severe inhibition of methanogenesis in unwashed GP6 cells caused by 5 μM propyl iodide and the role of methylcobalamin in regeneration of methane production in washed cells suggest the involvement of corrinoids in the methane pathway of the aceticlastic Methanosaeta concilii. This represents the first documentation for cobalt/methylcobalamin and sodium requirements for methanogenesis in Methanosaeta concilii. Key words: cobalt, sodium, methylcobalamin, methanogenesis, Methanosaeta concilii.
Cryptococcosis in beige mice: the effect of congenital defects in innate immunity on susceptibility
Authors: Salkowski Cindy A. , Balish Edward
Published: May 2010

The influence of the beige (bg/bg) mutation on susceptibility to cryptococcosis was assessed by mortality, quantitative culturing, and histopathology of infected organs from bg/bg and bg/+ mice. Immunodeficient bg/bg mice were more susceptible to systemic cryptococcosis than immunocompetent bg/+ mice. Differences in susceptibility of bg/bg and bg/+ mice corresponded with temporal differences in histopathology. In contrast to bg/+ mice, inflammatory responses in infected tissues from bg/bg mice contained less cellular infiltrate, proportionally more polymorphonuclear neutrophils than monocytes and macrophages, and delays in the switch from acute to chronic inflammation. Enhanced growth of Cryptococcus neoformans in the internal organs of bg/bg mice was coincident with delayed inflammatory responses. These quantitative culture and histopathology studies suggest that the defects associated with monocytes and macrophages and polymorphonuclear neutrophils resulted in altered in vivo inflammatory responses and contributed to the enhanced susceptibility of beige mice to C. neoformans. Key words: cryptococcosis, beige mice, inflammation, Cryptococcus neoformans, pathogenesis.
Galactose-fermenting mutants of Streptococcus thermophilus
Authors: Benateya Amina , Bracquart Patrice , Linden Guy
Published: May 2010

Three galactose-positive (Gal+) mutants were isolated after treating Streptococcus thermophilus strain CNRZ 302 with N-methyl-N′-nitro-N-nitrosoguanidine; other physiological and biochemical characteristics were retained. In contrast with the wild type's inability to utilize galactose, the A5 mutant metabolized 70% of the galactose resulting from the hydrolysis of lactose. Phosphoenolpyruvate-phosphotransferase activity could not be detected, indicating that this system was not involved in galactose transport. Galactokinase activities were higher in induced galactose-fermenting strains than in the galactose-negative strain. The mutation seemed to affect a galactokinase regulation gene. Key words: galactokinase, galactose, hydrolysis of lactose, mutants, Streptococcus thermophilus.
Further study on polyamine compositions in Vibrionaceae
Authors: Yamamoto Shigeo , Chowdhury M. A. R. , Kuroda Masako , Nakano Takako , Koumoto Yasuyoshi , Shinoda Sumio
Published: May 2010

It has previously been reported that norspermidine, one of the unusual polyamines, is present in Vibrio species. To expand this observation, the cellular polyamine compositions of additional species and strains in the family Vibrionaceae (Vibrio, Photobacterium, Listonella, and Shewanella) as well as Aeromonas species and Plesiomonas shigelloides, which have been proposed to be excluded from Vibrionaceae, were determined by using gas–liquid chromatography. Some Vibrio species previously reported were reexamined under the same conditions, and their results are included in this report. Norspermidine was detected as a major triamine in 23 of 24 Vibrio species, all of 4 Listonella species, and 3 of 5 Photobacterium species. Vibrio costicola, Photobacterium fischeri, and Photobacterium phosphoreum contained no norspermidine. Listonella species were indistinguishable from Vibrio species in their polyamine profiles. However, Shewanella putrefaciens ATCC 8071, formerly allocated in the genus Alteromonas, contained no norspermidine, and its polyamine profile was similar to those of four Aeromonas species, in which putrescine was exclusively found. Plesiomonas shigelloides was very similar to Escherichia coli in that putrescine and spermidine were predominant polyamines. Our data indicate that the occurrence of norspermidine may be very helpful as a generic marker in identification and classification of Vibrio and Listonella species. A gas–liquid chromatographic method with a nitrogen-selective detector was presented for rapid and sensitive detection of cellular norspermidine. Key words: polyamines, norspermidine, Vibrionaceae, taxonomy, Vibrio.
Fate of human enteric viruses, coliphages, and Clostridium perfringens during drinking-water treatment
Authors: Payment Pierre
Published: May 2010

The elimination of human enteric viruses, coliphages, and Clostridium perfringens was studied during a conventional complete drinking-water treatment process. The respective concentrations (geometric mean) of these microorganisms in 100-L samples of river water were, respectively, as follows: viruses, 79 mpniu (most probable number of infectious units) per 100 L, coliphages, 6565 pfu (plaque-forming units) per 100 L, and clostridia, 11 349 cfu (colony-forming units) per 100 L. After pre-disinfection, flocculation with alum, and settling, human enteric viruses were not detected in any of the 100-L samples (<4 mpniu/100 L), but coliphages were detected in 7 of 14 samples and clostridia in 15 of 16 samples. In filtered water samples, human enteric viruses were detected in 2 of 31 samples, coliphages in 10 of 33, and clostridia in 17 of 33. Finished water was free of human enteric viruses (0/162 samples), but coliphages were detected in one sample (1.5 pfu/100 L) and clostridia in three, at 1.0, 4.1, and 7.0 cfu/100 L. It thus appears that coliphages and clostridia, which are present in larger numbers than viruses in river water and which may have similar resistance to drinking-water treatments, may be useful for estimating the level of treatment attained when large volumes of water (1000 L or greater) are sampled. Key words: drinking water, removal, bacterial viruses, coliphages, Clostridium, enteric viruses.
Indigenous plasmids in Anabaena azollae: their taxonomic distribution and existence of regions of homology with symbiotic genes of Rhizobium
Authors: Plazinski Jacek , Croft Lynn , Taylor Rona , Zheng Qi , Rolfe Barry. G. , Gunning Brian E. S.
Published: May 2010

The method of horizontal agarose gel electrophoresis was used to demonstrate the presence of indigenous plasmid DNAs in different isolates of the symbiotic cyanobacterium Anabaena azollae. All isolates extracted from seven distinct species of the host fern Azolla were found to possess one to three cryptic plasmids ranging in sizes from 35 to 100 MDa (million daltons). Anabaenas isolated from Azolla caroliniana, Az. nilotica, and Az. pinnata species contained a single plasmid band of molecular mass approximately 60 MDa, whereas other endosymbiotic cyanobacteria extracted from Azolla filiculoides, Az. rubra, Az. mexicana, and Az. microphylla were shown to possess two or three covalently closed circular (CCC) DNAs. Cloned DNA fragments derived from the plasmid sequences of two different An. azollae isolates were used as hybridization probes. Hybridization data indicated that these symbiotic cyanobacteria possess different but related plasmid species and that it is possible to construct specific plasmid DNA probes capable of distinguishing among several strains of the symbiotic anabaenas. Several heterologous DNA probes, including Rhizobium symbiotic genes, were used to seek homologous sequences on the An. azollae plasmids. DNA sequences homologous to the nod box and nodMN genes were present on the Anabaena plasmids. Moreover, homology of a key Rhizobium exopolysaccharide (exoY) gene to the An. azollae CCC DNAs was detected. In addition, the introduction of the An. azollae plasmid clone into Rhizobium Exo− mutant (exoY) resulted in the Exo+ transconjugants. Those findings suggest that some of the An. azollae plasmids may play a role in symbiotic interactions with Azolla fem. Key words: Anabaena azollae, Azolla, symbiosis, cyanobacterium, plasmids.