bluuebunny/crossref_metadata_2025 huggingface dataset:
Rhizosphere competence of benomyl-tolerant mutants of Trichoderma spp.
Authors: Ahmad Jaleed S. , Baker Ralph
Published: May 2010

Two strains of Trichoderma harzianum and one each of T. koningii, T. polysporum, and T. viride were mutated for tolerance to the fungicide benomyl. Rhizosphere competence index of several mutants of each strain and species was determined by the rhizosphere competence assay. Most of the mutants and not their wild type parents were rhizosphere competent. When the strains and species were grown in Czapek–Dox broth for 6 days with cellulose as sole carbon source, the mutants produced significantly higher dry weight than their parent wild types. Neither the mutants nor the wild types produced biomass in glucose comparable to that in cellulose. Evidence indicates that Trichoderma spp. were induced by mutation to increase their linear growth rate and to become rhizosphere competent. Tolerance to benomyl does not seem to be a necessary attribute of rhizosphere competence.
Influence of aerobic microorganisms upon virus survival in soil
Authors: Hurst Christon J.
Published: May 2010

Survival of human poliovirus type 1 in a sandy loam soil appeared to be deleteriously influenced by aerobic microorganisms. This effect was determined by comparing the survival of virus in soil under four different possible combinations of aerobic versus anaerobic (H2–CO2) atmosphere and sterile versus nonsterile condition. Storage of samples was done in humid chambers to prevent soil desiccation. The effect attributed to aerobic microorganisms was measurable and statistically significant at all three incubation temperatures used in the study (1, 23, and 37 °C), with the increase in inactivation rate attributable to aerobic microorganisms generally being two to threefold. No comparable effect was observed to occur for anaerobic microorganisms under the sets of conditions employed in the study.
Cellular fatty acid comparison of strains of Corynebacterium michiganense subsp. sepedonicum from potato and sugar beet
Authors: Gudmestad Neil C. , Henningson Paul J. , Bugbee William M.
Published: May 2010

The cellular fatty acid composition of Corynebacterium michiganense subsp. sepedonicum strains recovered from potato and sugar beet hosts were determined using gas-liquid chromatography. Fatty acid profiles were compared to profiles from other plant pathogenic coryneform bacteria. The most prevalent fatty acids present in C. michiganense subsp. sepedonicum were 12-methyl-tetradecanoic acid (a15:0), 14-methyl-hexadecanoic acid (a17:0), 14-methyl-pentadecanoic acid (i16:0), 12-methyl-4-tetradecenoic acid (a15:1), hexadecanoic acid (16:0), cis-9-octadecenoic acid (18:1c), and cis-9,12-octadecadienoic acid (18:2). In addition, some strains contained smaller amounts of 14, 15, 16, 17, 18, and 19 carbon fatty acids. All strains of plant pathogenic coryneform bacteria tested could be differentiated on the basis of either total fatty acid content (qualitative) or by ratios of cellular fatty acids (relative quantitative differences), e.g., a15:0/i16:0, a17:0/i16:0, a15:0/a17:0, i16:0/a15:1, a15:1/16:0, and 16:0/18:1. Strains of C. michiganense subsp. sepedonicum from sugar beet and potato were qualitatively and quantitatively very similar. On the basis of these results, it was clear that the endophytic strains of C.m. subsp. sepedonicum recovered from healthy sugar beets were indistinguishable from pathogenic strains recovered from potato. The bacteria from the two hosts should be considered as members of the same subspecies.
Inhibition of Bacillus thuringiensis proteases and their effects on crystal toxin proteins and cell-free translations
Authors: Bibilos Margaret , Andrews Jr. Robert E.
Published: May 2010

Proteases produced during growth and sporulation of four strains of Bacillus thuringiensis were examined. Low levels of proteolytic activity were detected during the late exponential phase of growth in all four strains: two strains of B. thuringiensis subsp. kurstaki and one strain each of subsp. israelensis and berliner. In all strains, protease activities increased dramatically at the onset of sporulation. The principal proteases, both extra- and intra-cellular, were neutral, metal-loproteases. The pH optima and substrate specificities of proteases extracted from cells in various stages of growth and sporulation indicated that substantial diversity existed among the strains. Intracellular proteases from all four strains converted the 135 000 molecular weight protoxin of strain HD251, an isolate previously shown to have reduced intracellular proteolytic activity and which normally does not contain a protein of the lower molecular weight, to a 68 000 molecular weight toxin. Cell-free translational activity of extracts from strain HD251 were approximately fivefold more active than were equivalent extracts from strain LB1 presumably because of the reduced intracellular proteolytic activity of this strain.
Locomotory characteristics of Treponema denticola
Authors: Pietrantonio Frank , Noble P. B. , Amsel Rhonda , Chan E. C. S.
Published: May 2010

Locomotion of pathogenic spirochetes has been suggested as a virulence factor in their pathogenesis. Little is known of the locomotory characteristics of oral anaerobic spirochetes. We have determined the optimal conditions for motility of seven strains of Treponema denticola in menstrua of different viscosities. The viscosity for optimum motility for all strains was found to be 9.57 centipoises at 25 °C. Under these conditions the average speeds for each strain was computed from the motility tracks as recorded by timed exposures under dark-field microscopy. Differences in speeds were found between the various strains. In addition, we have determined the "persistence" (direct distance/actual pathlength travelled) of cell movement of each strain. Interstrain differences were also noted. These locomotory characteristics contribute to the locomotory phenotypes of the various strains and therefore may aid in their characterization and provide an insight into locomotion as a virulence factor in periodontitis.
Survival of Yersinia enterocolitica in the environment
Authors: Chao Wei-Liang , Ding Ren-Jei , Chen Ren-Shen
Published: May 2010

When Yersinia enterocolitica was introduced into soils (or physiological saline), very little decrease in the population was observed throughout the test period. If the soil was allowed to air dry slowly, only 0.1% (2.8 × 103 colony forming units/g of soil) of the original population added still remained viable by day 10. On the other hand, the introduced organisms disappeared rapidly in river water but their longevities could be extended significantly if a eucaryote inhibitor was added to the river water or the river water was passed through a 0.8-μm membrane filter to remove eucaryotic predators. Furthermore, the rapid decrease of the Yersinia population coincided with an increase in numbers of protozoans. However, when Yersinia was added to filter-sterilized river water or when small numbers of the organism, below the threshold level believed necessary for active predation to occur, were added to the river water, no response in predators was observed; nevertheless, the population of Yersinia still showed a continued decline. When the organism was introduced into sephadex-treated river water or groundwater, its survival improved significantly compared with its survival in nontreated water samples. Low ambient temperature dramatically increased its ability to survive in the aquatic environment. It is concluded that, in addition to the temperature factor, the longevity of Y. enterocolitica in river water is chiefly regulated by predators and toxin producers.
Ultrastructure of the in situ adherence of Mobiluncus to vaginal epithelial cells
Authors: Boer Jan M. De , Plantema Friso H. F.
Published: May 2010

From patients with bacterial vaginosis motile, anaerobic, comma-shaped bacteria can be isolated, which have recently been placed into the new genus Mobiluncus. In this study, electron microscopy was used to examine the in situ adherence of these motile curved rods to detached epithelial cells (comma cells) in vaginal fluid from two patients with bacterial vaginosis. Thin sections showed that the curved rods attached both directly to the epithelial cell surface and at various distances from it. It is concluded that after initial attachment these motile bacteria can grow at the epithelial cell surface in sessile microcolonies. Ruthenium red staining demonstrated a coating of precipitated glycocalyx material both on the surface of the curved rods and on their flagella. This may indicate that in situ the adherent curved rods were enclosed in a very hydrated matrix of exopolysaccharides. Conspicuous was the ability of the curved rods to attach to the epithelial cell surface via their cell tips. However, in situ no specialized bacterial cell surface structures were seen that might explain this polar attachment. Electron microscopy of pure cultures demonstrated that both Mobiluncus curtisii subsp. curtisii and Mobiluncus mulieris can produce a glycocalyx in vitro.
Production of acetyl xylan esterase by Trichoderma reesei and Schizophyllum commune
Authors: Blely P. , MacKenzie C. R. , Schneider H.
Published: May 2010

Activity of acetyl xylan esterase, an enzyme that removes acetyl groups from acetyl xylan, was coproduced with that of endoxylanase and endoglucanase in two Trichoderma reesei strains and one Schizophyllum commune strain. The levels of activity of extracellular enzymes were measured during the course of cultivation on different carbon sources. The highest activity levels of acetyl xylan esterase were produced by T. reesei QM 9414 in a xylan plus cellulose medium and by S. commune in a cellulose medium. Both strains produced low levels of acetyl xylan esterase activity in glucose, xylose, and cellobiose media. Schizophyllum commune also produced low levels of acetyl xylan esterase activity in xylan and acetyl xylan media. Trichoderma reesei RUT C-30 behaved like a catabolite repression resistant mutant and produced higher enzyme levels than the QM 9414 strain on all carbon sources examined. Analytical gel electrophoresis and isoelectric focusing demonstrated that the acetyl xylan esterase activity of S. commune was represented as one major form (pI 3.4) which also hydrolyzed 4-methylumbelliferyl acetate. The esterase systems of T. reesei strains were found to be more complex than those of S. commune. The pattern of coproduction of the various activities suggested that acetyl xylan esterase is a component of the cellulolytic system of the fungi tested.
Yeast flocculation: competition between nonspecific repulsion and specific bonding in cell adhesion
Authors: Kihn Jean Claude , Masy Charlotte L. , Mestdagh Michèle M.
Published: May 2010

Yeast flocculation is governed by the competition between electrostatic repulsion (nonspecific interaction) and polysaccharide–protein bonds (specific interaction). The electrical surface potential, which is mainly due to phosphodiester linkages (of the cell wall phosphomannan), maintains the cells dispersed. Polysaccharides and proteins of the cell surface can readily penetrate the potential barrier and may establish specific bonds. The specific inhibition of flocculation by various mannosyl derivatives suggested that the protein receptor binds to the group Manα → 3 Manα → [Formula: see text] → 6 Manα → 2 Manα … of phosphomannan. Calcium, which is required for flocculation, could act as a bridge between the negatively charged groups of phosphomannan and those of the protein receptor. The role of calcium, however, cannot be restricted only to charge neutralization because other divalent cations inhibit flocculation; our results show that cation binding is governed by strong stereochemical constraints. Studies on protein-polysaccharide interactions have shown that electrical charges may remain uncompensated at short distance, but can be stabilized by hydrogen bonds. Calcium could induce a "locked" conformation of the receptor; this conformation is the only one capable of binding phosphomannan strongly enough to make cell adhesion possible.
Growth of rhizosphere-competent mutants of Trichoderma harzianum on carbon substrates
Authors: Ahmad Jaleed S. , Baker Ralph
Published: May 2010

When the strains of Trichoderma harzianum were grown in Czapek-Dox broth without saccharose with cotton linters, microcrystalline cellulose, wood cellulose, or xylan as a sole source of carbon, the rhizosphere-competent mutants produced significantly higher biomass than the rhizosphere-incompetent wild types. Both mutants and wild types did not readily grow on glucose, galactose, cellobiose, or xylose as sole source of carbon. The mutants, T-95 and T-12B, produced significantly higher biomass when grown on complex carbohydrates with added simple sugars. The wild types did not produce significantly greater biomass when both simple and complex sugars were the carbon sources than when either substrate was used alone. The ability of the mutants to grow more rapidly on complex carbon substrates (typical of those found on root surfaces) than their wild-type parents, and to increase biomass when simple sugars were added along with the cellulose substrate could be of ecological significance and a characteristic of rhizosphere competence.
Transport of yeast vacuolar trehalase to the vacuole
Authors: Harris Steven D. , Cotter David A.
Published: May 2010

We have tested yeast secretory mutants, which define different stages of the secretory pathway, for their levels of vacuolar trehalase activity. Mutations that cause accumulation of secretory proteins in the endoplasmic reticulum or in the Golgi body lead to diminished vacuolar trehalase activity. Mutations that cause accumulation of secretory vesicles have no effect on vacuolar trehalase activity. None of the mutations affects cytoplasmic trehalase activity. These results provide further evidence for the existence of a compartmentalized trehalase in yeast, and demonstrate that the enzyme enters the secretory pathway.
Antifungal susceptibility testing of Trichosporon beigelii to imidazole compounds
Authors: McBride M. E. , Kalter D. C. , Wolf Jr. J. E.
Published: May 2010

Twenty-two strains of Trichosporon beigelii have been tested for susceptibility to imidazole compounds. Ten strains were isolated from untreated genital white piedra lesions and 12 were from the same patients following treatment failure with imidazole compounds. Agar dilution and disk elution methods were compared using two media: yeast nitrogen base and antibiotic assay medium 3 (Difco). Antifungal agents tested were econazole, miconazole, ketoconazole, clotrimazole, and amphotericin B in concentrations of 0.0625–32 μg/mL. The most consistent results occurred with antibiotic assay medium 3 and the agar dilution method giving minimal inhibitory concentrations between 0.0625 and 0.25 μg/mL. Using yeast nitrogen base agar, minimal inhibitory concentrations were higher ranging from 0.0625 to 2.0 μg/mL. End points of growth in the disk elution method were not clearly delineated and ranged from 0.0625 to 8.0 μg/mL. The distribution of minimal inhibitory concentrations obtained using different media and methods were compared by χ2 analysis, and the medium was found to significantly change the minimal inhibitory concentrations. There was no difference in the susceptibility of strains of T. beigelii to imidazole compounds whether isolated before or after treatment. It was concluded that in vitro susceptibility of T. beigelii to imidazole compounds did not necessarily predict efficacy in vivo.
The soil environment and the suppression of saprophytic growth of Gaeumannomyces graminis var. tritici
Authors: Simon A. , Sivasithamparam K.
Published: May 2010

The effect of the soil environment on the transferable suppression of the saprophytic growth of Gaeumannomyces graminis var. tritici (pathogen suppression) was studied in a field soil acidified to pH 4.3 by annual treatment with ammonium sulphate for 9 years and in the same soil further amended with a single application of lime (pH 5.4). Pathogen suppression and the activity of Trichoderma spp. were greater when (i) the unlimed (pathogen-suppressive) soil was added at a rate of 1% (w/w) to the same soil treated with γ-radiation than when added at the same rate to the irradiated limed soil; (ii) the limed (pathogen-conducive) soil was added at 1% (w/w) to the irradiated unlimed soil than when added at the same rate to the irradiated limed soil. Pathogen suppression and the activity of Trichoderma spp. were increased in both soils with the addition of an antibacterial agent. The saprophytic growth of G. graminis var. tritici was reduced in the unsterile pathogen-suppressive but not in the pathogen-conducive soil, following the addition of inoculum of T. koningii. It is proposed that both the abiotic and biotic environments of soil can influence the expression of transferable pathogen suppression which, in the soils tested, is related to the activity of Trichoderma spp.
Electrophoretic and zymogram analysis of the cytoplasmic soluble protein fraction of Spiroplasma citri
Authors: Wagih Elsayed E. , Fletcher Jacqueline
Published: May 2010

The biological function of proteins in the soluble cytoplasmic fraction of two isolates of Spiroplasma citri was investigated by zymogram analysis. There were quantitative and qualitative differences in the isozyme patterns of esterase and RNase between the two isolates of S. citri. Esterase activity in S. citri, reported here for the first time, was higher in one isolate, while RNase activity was higher in the other. No activity was detected in either isolate for acid phosphatase, alkaline phosphatase, or peroxidase. Spiralin, detected in the the cytoplasmic fraction using both native and denaturing polyacrylamide gel electrophoresis, did not appear to be an isozyme of any of the enzymes tested.
Comparison of spore proteins among species of the cellular slime moulds Dictyostelium and Polysphondylium as examined by immunological cross-reactivity
Authors: Yamada Yohko , Okamoto Koji , Takeuchi Ikuo
Published: May 2010

Spore proteins of six cellular slime mould species, Dictyostelium discoideum, D. mucoroides, D. purpureum, D. lacteum, Polysphondylium violaceum, and P. pallidum were studied. The spore proteins were cross-reacted with four different polyclonal antibodies produced against D. mucoroides spores and D. discoideum major spore coat proteins SP96, SP70, and SP60 by SDS polyacrylamide gel electrophoresis and immunoblotting. The spore proteins of D. discoideum and D. mucoroides showed the strongest cross-reactivity with all the antisera and also produced many common protein bands, thus reflecting their morphological similarities. Polysphondylium violaceum, which is quite distinct in morphology from D. discoideum and D. mucoroides, produced the second strongest cross-reactivity. In contrast, the proteins of D. purpureum showed little cross-reactivity, although morphologically it closely resembles D. mucoroides. The developmental changes of these spore proteins were investigated by cross-reacting the antisera against vegetative and slug cell proteins. In the cases of D. discoideum and D. mucoroides, the band patterns of slug proteins coincided with those of spores, which suggested that most of the spore proteins had already accumulated at the slug stage. However, this was not the case with P. violaceum, which suggested that spore proteins of this species cross-reactive with the antisera were synthesized or modified at the culmination stage.
Coliphages and enteric viruses in the particulate phase of river water
Authors: Payment Pierre , Morin Eric , Trudel Michel
Published: May 2010

The present study was undertaken to determine if indigenous enteric viruses and coliphages are free or associated with suspended particulate matter in natural waters. River water was filtered on filters of decreasing porosities (100–0.25 μm) that were pretreated with detergent to eliminate viral adsorption while retaining particulates. This filtered water was refiltered in virus-adsorbing conditions to retain free viruses. The virus-adsorbing filter retained most of the enteric viruses (77.4%) and coliphages (65.8%), which indicated that these viruses were probably free or associated with particles with a diameter of less than 0.25 μm. These observations are important because in water treatment plants small particulates are often the most difficult to eliminate.
Succinate-induced swelling in a variety of rhizobia
Authors: Urban James E. , Nelke Melissa
Published: May 2010

The morphological effects of exposure to 16.6 mM succinate were evaluated in Bradyrhizobium japonicum, Rhizobium leguminosarum, R. lupini, R. meliloti, R. phaseoli, and R. trifolii. Strains evaluated included laboratory strains and natural isolates. Each of the strains tested showed swelling, but the degree and type of swelling varied between strains. Generally, the species which show swelling as bacteroids within nodules displayed the most swelling in succinate, and the morphology of those cells showed the greatest similarity to nodule-derived bacteroids.
Cross protection between a strain of Staphylococcus epidermidis and eight other species of coagulase-negative staphylococci
Authors: Yoshida K. , Umeda A. , Ichiman Y. , Yamada T.
Published: May 2010

Passive protective activity of rabbit antiserum prepared by a representative capsular type II strain of Staphylococcus epidermidis in mice was absorbed out with homologous capsular type strains of S. simulans, S. cohnii, S. xylosus, S. hominis, S. capitis, S, hyicus, S. haemotyticus, and S. saprophytics in addition to the homologous strain. The minimum amount of the strains required for absorption differed greatly, depending upon the strain. No absorption of the activity was shown with a strain of capsular type I and III of S. epidermidis, S. simulans, and S. cohnii, and a strain of capsular type III of S. hominis. These results suggest a possible capsular type specificity in the cross protection between strains of S. epidermidis and other species of coagulase-negative staphylococci.
Establishment of Bacteroides succinogenes and measurement of the main digestive parameters in the rumen of gnotoxenic lambs
Authors: Fonty G. , Gouet P. , Ratefiarivelo Harinirina , Jouany J. P.
Published: May 2010

We attempted to determine the degree of diversification of the microflora that allow the establishment of Bacteroides succinogenes S85 in the rumen of gnotoxenic lambs. Four lambs (group I) received an inoculum orally, composed of 182 noncellulolytic bacterial strains (inoculum 1) previously isolated from the rumen of conventional young lambs. Two lambs (group II) were inoculated with 32 strains (inoculum 2) selected among the 182 strains of inoculum 1. Two lambs (group III) received an inoculum (inoculum 3) composed of 106 noncellulolytic bacterial strains previously isolated from the rumen of meroxenic lambs. Two lambs (group IV) were inoculated with 16 strains (inoculum 4) chosen among the 106 strains of inoculum 3. All lambs were inoculated from birth except two lambs of group I, which were inoculated from 1 month of age. Each lamb then received orally a pure culture of B. succinogenes. This strain became established more easily in the rumen of lambs that had received complex inocula (group I). Its population reached a level close to that generally observed in conventional lambs (107–108 bacteria mL−1). In contrast, B. succinogenes became established in only one lamb of group II, but bacterial numbers varied considerably. In group III, repeated inoculations were necessary to obtain its definitive establishment (107–108 bacteria mL−1 after weaning). In spite of several inoculations, this cellulolytic species failed to establish in the rumen of lambs of group IV, which had received the less complex inoculum. The volatile fatty acid levels were very different from one lamb group to another. The more complex the inoculum administered to the animals, the higher the concentration. In those that received inoculum 1, the volatile fatty acid concentration was similar to that measured in conventional lambs fed the same diet (approximately 80 mmol L−1 after feeding). In lambs inoculated with only 16 strains there were almost no fermentations (30 mmol L−1 of volatile fatty acid). These results demonstrate that the establishment of cellulolytic bacteria, functions of the rumen, and the stability of the ecosystem depend on the complexity and diversity of the microflora. In the light of present knowledge, it is not possible to determine accurately the operative composition of the minimum flora enabling rumen development and function.
Interactions between Pythium nunn and Pythium ultimum on bean leaves
Authors: Paulitz T. C. , Baker R.
Published: May 2010

Colonization of bean leaf fragments by Pythium nunn and Pythium ultimum in naturally and artificially infested soils was studied. In soil naturally infested with both P. ultimum and P. nunn (Ascalon sandy loam), the fungi colonized 20 and 0% of the fragments after 6 h, and 54 and 78% after 12 h, respectively. After 24 h, 73% of the fragments were co-colonized by both fungi, but after 72 h, less than 10% of the fragments were colonized by P. ultimum, and over 90% were colonized by P. nunn. In soil artificially infested with P. nunn (300 cfu/g), colonization by P. ultimum was significantly reduced after 18 h. Similar trends were observed in aerated–steamed and other soils artificially infested with P. nunn. When fragments were precolonized by P. ultimum for 24 h and then challenged with P. nunn, 77% were colonized by P. nunn after 24 h. In the reciprocal treatment, less than 5% of the fragments precolonized by P. nunn were colonized by P. ultimum. In bean leaf fragments placed in aerated–steamed soil, P. nunn reduced the density of sporangia of P. ultimum. This evidence suggests that P. nunn is both a primary and secondary colonizer capable of possession of substrates previously occupied by P. ultimum, and that P. nunn can displace P. ultimum from bean leaf fragments.
Detection of animal and human enteric viruses in water from the Assomption River and its tributaries
Authors: Payment Pierre , Affoyon Florentin , Trudel Michel
Published: May 2010

Animal enteroviruses, reoviruses, and human enteric viruses were detected in water samples (20 L) from a major river system, the Assomption River in the province of Quebec. Animal enteroviruses, probably of porcine origin (this region is a major producer of pork), were isolated on porcine cell cultures and were found in 29 to 60% of water samples from the different sites on the river and in 19 to 48% of the water samples from the tributaries. The average concentration of these animal enteroviruses in water from the Assomption River was 2 to 7 mpniu/L (most probable number of infectious units per litre), and that from the tributaries varied from 3 to 24 mpniu/L. Reoviruses were detected in infected cell cultures by an enzyme-linked immunosorbent assay. Their origin is probably avian (broiler chicken farms) or human (untreated domestic waste waters) and they were detected in 19 to 52% of the water samples from the Assomption River at an average concentration of 3 to 12 mpniu/L. In water samples from the tributaries, 5 to 71% of the samples were positive at an average concentration of 5 to 24 mpniu/L. Human enteric viruses were detected in MA-104 cells by an immunoperoxidase assay using human immune serum globulin. They were detected in 13 to 72% of water samples from the Assomption River and 14 to 71 % of the water samples from the tributaries. The average concentration of these human enteric viruses in Assomption River water varied from 1 to 12 and from 2 to 145 mpniu/L in water samples from the tributaries. Seasonal patterns were observed for all viruses with an increase in viral concentration in early fall.
Detection of a lactobacillus substance that inhibits Escherichia coli
Authors: McGroarty Jacqueline A. , Reid Gregor
Published: May 2010

Recent studies have shown that certain lactobacilli strains have the ability to interfere with the adherence and growth of uropathogenic bacteria. This interaction is believed to be important in the maintenance of a normal urogenital flora and in the prevention of infection in females. In the present study, Lactobacillus casei ssp. rhamnosus GR-1 and Lactobacillus acidophilus 76 were found to exert an inhibitory effect on pyelonephritogenic mutant Escherichia coli Hu 734 and E. coli ATCC 25922. The bioactivity of the inhibitor produced by strain GR-1 was retained under pH buffered conditions and was bactericidal. The bioactive substance was heat labile, not precipitated by up to 80% ammonium sulphate, and extractable in chloroform. The data indicated that the inhibitor is not lactic acid or hydrogen peroxide and has a molecular weight greater than 12 000 – 14 000. Human urine supported production of the inhibitor and reduced and delayed outgrowth of the E. coli. The ability of L. casei GR-1 and possibly other lactobacilli strains to produce inhibitors of uropathogenic bacteria may have clinical importance and significance in the microbial ecology of the urogenital tract.
Characterization of two DNA clones specific for identification of Corynebacterium sepedonicum
Authors: Verreault H. , Lafond M. , Asselin A. , Banville G. , Bellemare G.
Published: May 2010

Escherichia coli TB1 was transformed with pUC9 containing fragmented DNA (4–10 kilobases (kb)) from Corynebacterium sepedonicum. The resulting genomic bank was screened by a dot blot assay to identify clones specifically hydridizing to C. sepedonicum DNA and not to the DNA of several other Gram-positive and Gram-negative bacteria. Two clones (III24 and III31) were selected because of their ability to strongly hybridize to C. sepedonicum DNA and weakly hybridize to the DNA of C. michiganense, Erwinia carotovora, Agrobacterium tumefaciens, Bacillus subtilis, Pseudomonas solanacearum, Micrococcus luteus, and Arthrobacter globiformis. These two clones were also specific for C. sepedonicum DNA when tested against the DNA from 30 isolates of soil bacteria. Restriction enzyme analysis has shown that the two clones have an insert of 8 kb (III24) and 4 kb (III31). On the basis of restriction enzyme patterns, one clone (III24) does not correspond to plasmid pCL 50, a cryptic plasmid found in several C. sepedonicum isolates. Because purified III24 and III31 DNA can be used to detect approximately 1 ng of C. sepedonicum genomic DNA, the two clones can complement serological or biological detection methods. This could be useful, especially when a high degree of specificity is required for detection or identification of this plant pathogen.
Bacteria–lectin interactions in phytohemagglutinin-induced bacterial overgrowth of the small intestine
Authors: Ceri Howard , Falkenberg-Anderson Karen , Fang Rixun , Costerton J. W. , Howard Richard , Banwell J. G.
Published: May 2010

The mechanism of phytohemagglutinin-induced bacterial overgrowth of the small bowel in the rat was studied. Interaction of the lectin with bacterial isolates selected at random from those that comprised the major population of the over-growth was determined. In both bacterial agglutination assays and glycocalyx stabilization, no specific association between lectin and bacteria was seen. In three independent binding assays phytohemagglutinin was not found to increase bacterial adherence to washed intestinal mucosa. Phytohemagglutinin would not appear to act, therefore, as a direct ligand to mediate bacterial adherence or to modify the mucosal surface to increase bacterial adherence.
Seroepidemiology of Q fever in New Brunswick and Manitoba
Authors: Marrie Thomas J.
Published: May 2010

A seroepidemiological survey, using an indirect immunofluorescence test, was carried out on serum samples obtained from New Brunswick and Manitoba blood donors during 1986. The antigens were Coxiella burnetii phase I and phase II from strain Nine Mile. Eighty of the 503 (15.9%) Manitoba blood donors had a phase II antibody titer of ≥ 1:8, while 41 (4.2%) of the 966 New Brunswick blood donors had such antibodies. We have recently diagnosed three cases of Q fever in New Brunswick but none have been diagnosed in Manitoba. Our data suggest that Q fever may be increasing in New Brunswick and repeated seroepidemiological studies are indicated. It is likely that undetected cases of Q fever are occurring in Manitoba.
Hemagglutinating properties of Actinobacillus pleuropneumoniae
Authors: Jacques Mario , Roy Geneviève , Mittal K. R.
Published: May 2010

A total of 26 isolates of Actinobacillus pleuropneumoniae were tested for their ability to agglutinate erythrocytes of different origins. Seven different hemagglutination patterns were found. Ten (38%) isolates did not agglutinate any of the erythrocytes tested. The remaining 16 (62%) isolates agglutinated human erythrocytes, and among these, 12 also agglutinated rat, cat, dog, guinea pig, or bovine erythrocytes. No correlation was found between the seven different hemagglutination patterns observed and the serotypes. Hemagglutination activity was destroyed by heating at 100 °C as well as by formaldehyde treatment, but was not affected by heating at 60 °C, by treatment with trypsin or pronase, or by homogenization of bacterial cells. No fimbriae were observed on examination of bacterial cells negatively stained with phosphotungstate using electron microscopy. Hydrophobic surface properties of the isolates were evaluated. All the isolates appear to possess a hydrophilic cell surface. The present study provides evidence that certain isolates of A. pleuropneumoniae possess hemagglutinating properties which do not appear to be mediated by fimbriae or to involve hydrophobic interactions.
Topographical stability of lateral regions of the Schizosaccharomyces pombe plasma membrane as revealed by invagination characteristics
Authors: Takeo Kanji , Nishimura Kazuko , Miyaji Makoto
Published: May 2010

The characteristics, especially the stability, of plasma-membrane invaginations in Schizosaccharomyces pombe were studied using freeze-fracture techniques. The plasma membrane of exponential-phase S. pombe was characterized by the uninvaginated growing pole(s) and by the existence of particularly long invaginations, reaching up to 5 μm, in the nongrowing lateral regions. The stationary-phase plasma membrane was characterized by densely invaginated cell poles and by the high density of invaginations. After reinoculation of stationary-phase cells in fresh media, preexisting invaginations in the cell poles disappeared when the latter became the growing pole. In lateral regions of the plasma membrane, however, deep invaginations, characteristic of the stationary phase, were well conserved. The results obtained suggest the topographical stability of nongrowing lateral regions of the S. pombe plasma membrane.
Identification of rumen bacteria that anaerobically degrade nitrite
Authors: Cheng K. -J. , Phillippe R. C. , Majak W.
Published: May 2010

Fifty-one pure strains of rumen bacteria, representing 15 genera, were tested for their ability to metabolize nitrite. Twenty-five of the strains, belonging to eight genera, were capable of growth and nitrite metabolism in nitrite-containing medium sterilized by autoclaving. An additional 10 strains showed growth and nitrite metabolism in medium that was autoclaved before the addition of filter-sterilized nitrite. Nitrite metabolism was not observed in the remaining 16 strains, and these were also incapable of growth in the presence of nitrite. Ammonia was produced during nitrite reduction by Megasphaera elsdenii J1. In agreement with previous studies, abiotic losses of nitrite were observed during autoclaving and storage of media, but losses of nitrite due to bacterial metabolism were much greater.
A physical method for separating Saccharomyces cerevisiae cells according to their ploidy
Authors: Vágvölgyi C. , Kucsera J. , Ferenczy L.
Published: May 2010

A centrifugation technique, using genetically marked Saccharomyces cerevisiae strains, has been developed to separate Saccharomyces cerevisiae cells of different ploidy levels from exponential phase cultures. The method involves the conversion of yeast cells to protoplasts, the separation of the protoplasts on an osmotically stabilized Nycodenz gradient, and their regeneration. This type of selection may be of importance where selectable markers are not available.
Sexual co-flocculation and asexual self-flocculation in budding and fission yeasts: experimental establishment of a fundamental difference
Authors: Johnson Byron F. , Walker Teena , Calleja Gode B. , Seligy Verner L.
Published: May 2010

Heavily flocculated yeasts were resuspended in a variety of sugar syrups and solutions. Asexual Saccharomyces floes remained patent in water and in 50% galactose but dispersed in 50% mannose and in 10 mM EDTA. Asexual Schizosaccharomyces floes (either h− or h+) remained patent in water and in 50% mannose but dispersed in 50% galactose and 10 mM EDTA. Sexual Schizosaccharomyces floes (homothallic NCYC 132, or heterothallic h− and h+ combined) remained patent in water, in 50% galactose, in 50% mannose, and in 10 mM EDTA. Dispersal of asexual floes in sugar syrups and EDTA suggests that asexual flocculation is mediated by protein–carbohydrate lectinlike interactions stabilized by Ca2+. Failure of the sexually flocculent fission yeasts to disperse in any of these diagnostic solutions suggests that sexual flocculation is mediated by protein–protein interactions in which Ca2+ is irrelevant.
Analysis of antibiotic susceptibility and extrachromosomal DNA content of Ruminococcus albus and Ruminococcus flavefaciens
Authors: Champion Kathleen M. , Helaszek Carla T. , White Bryan A.
Published: May 2010

Seventeen Ruminococcus albus and Ruminococcus flavefaciens strains have been screened for naturally occurring antibiotic resistance, as determined by zones of inhibition from antibiotic disks. These strains were also examined for extrachromosomal DNA content. All strains screened are resistant to low levels (10–200 μg/mL) of streptomycin. In contrast to the previously reported data, we have found that R. flavefaciens C-94 is now susceptible to both kanamycin and tetracycline. However, R. flavefaciens FD-1 is not susceptible to kanamycin (minimum inhibitory concentration (MIC) = 40 μg/mL). Furthermore, R. albus 8 is resistant to tetracycline (MIC = 40 μg/mL), and erythromycin (MIC = 100 μg/mL). Six freshly isolated strains showed resistance to tetracycline (35–70 μg/mL), and all tetracycline-resistant strains also showed resistance to minocycline. None of these Ruminococcus determinants share homology with the streptococcal tetL, tetM, or tetN determinants. All 17 strains were screened for extrachromosomal DNA content. Nine different techniques for the detection and isolation of extrachromosomal DNA were tested. However, owing to difficulties in demonstrating or isolating plasmid DNA, it has not been possible to determine if these antibiotic resistance genes are plasmid borne. Evidence is presented to suggest that the presence of oxygen may affect the quality of the DNA obtained from Ruminococcus.
Degradation of polycyclic aromatic hydrocarbons and aromatic heterocycles by a Pseudomonas species
Authors: Foght J. M. , Westlake D. W. S.
Published: May 2010

Enrichment cultures were established with the aromatic fraction of a crude oil and screened for aromatic-degrading pseudomonads, using a sprayed plate technique. One isolate identified as Pseudomonas sp. HL7b was chosen for further study because it oxidized several polycyclic aromatic hydrocarbons and aromatic heterocycles without an apparent lag. Using capillary gas chromatography, spectrophotometry, and radiorespirometry, it was found to be capable of mineralizing and (or) oxidizing a wide range of polycyclic aromatic hydrocarbons, S-, N-, and O-heterocyclic analogues, and alkyl polycyclic aromatic hydrocarbons, but not aliphatic hydrocarbons. The isolate displayed two colonial morphologies which correlated with variation in degradative phenotype and hydrophobicity as measured by polystyrene adherence. Four cryptic plasmids were observed in both colonial types. Pseudomonas sp. HL7b degraded dibenzothiophene co-metabolically by a recognized pathway, but this degradation was constitutive, rather than inducible as reported for other bacteria.
A rapid purification procedure for pyruvate kinase from the hyphal fungus Aspergillus nidulans
Authors: Kester Harry C. M. , Uitzetter Jos H. A. A. , Graaff Leo H. de , Visser Jaap
Published: May 2010

Pyruvate kinase was purified from the filamentous fungus Aspergillus nidulans with a 45–55% yield. The procedure involved dye-affinity chromatography and fast protein liquid chromatography, resulting in highly active and pure enzyme in milligram quantities within 2 days. The purified enzyme, a tetramer with a subunit molecular weight of 65 000 and an isoelectric point of 4.7, was used to determine the amino acid composition.
Stimulatory effect of manganese and glycine derivatives on production and release of β-galactosidase by alkalophilic Bacillus no. C-125
Authors: Ikura Yoko , Horikosh Koki
Published: May 2010

Mn2+, glycine, glycine derivatives, amino acid analogues, and D-amino acids were investigated for their role in the production and release of β-galactosidase by alkalophilic Bacillus no. C-125. The simultaneous addition of Mn2+ and either glycine methyl ester, glycine ethyl ester, or glycinamide markedly increased the production and release of the enzyme. The addition of more than 100 μM Mn2+ was indispensable for increased enzyme production and release even in a nutrient-rich medium. When both Mn2+ and 2.0% glycine ethyl ester were added simultaneously, the maximum cell mass increased 3.6-fold, the maximum total activity, 19.8-fold, and 65% of the total activity was found extracellularly. Protease production was stimulated by Mn2+ but repressed by glycine ethyl ester. The simultaneous addition of Mn2+ and 2.0% glycine ethyl ester repressed protease activity strongly. The extracellular protein: nucleic acid ratio was higher in the presence of both Mn2+ and glycine ethyl ester, indicating that this method is advantageous for practical application to extracellular accumulation of intracellular proteins. The simultaneous addition of Mn2+ and glycine ethyl ester to the medium decreased the stability of protoplasts, especially at alkaline pH.
Biosurfactant production and diauxic growth of Rhodococcus aurantiacus when using n-alkanes as the carbon source
Authors: Ramsay B. , McCarthy J. , Guerra-Santos L. , Kappeli O. , Fiechter A. , Margaritis A.
Published: May 2010

When grown on hydrocarbons, Rhodococcus aurantiacus produced four glycolipid biosurfactants which could lower the surface tension of distilled, deionized water to between 26 and 30 nM∙m−1. The biosurfactants were found both extracellularly and associated with the cells. They could be extracted with solvents such as chloroform and pentane. Greater quantities of biosurfactant were produced when NaNO3 was used in place of (NH4)2SO4 as the nitrogen source. When grown on n-alkanes using (NH4)2SO4 as the nitrogen source, R. aurantiacus exhibited an unusual form of diauxic growth. Data suggested that the mechanism of diauxy involved changes in the degree of cell-surface hydrophobicity which resulted in hydrocarbon-transport limitation.
Biosynthesis of ε-rhodomycinone from glucose by Streptomyces C5 and comparison with intermediary metabolism of other polyketide-producing streptomycetes
Authors: Dekleva Michael L. , Strohl William R.
Published: May 2010

The catabolism of glucose by Streptomyces C5, a producer of anthracycline antibiotics, was investigated to determine the pathways that supply precursors for anthracycline biosynthesis. Carbons for the biosynthesis of ε-rhodomycinone, an anthracycline aglycone, from radiolabelled glucose were derived primarily from the Embden–Meyerhof–Parnas pathway, with a minor contribution from the pentose phosphate pathway. Furthermore, the anthracycline-producing strain, Streptomyces C5, as well as Streptomyces aureofaciens and Streptomyces lividans, strains that produce nonanthracycline polyketide antibiotics, displayed enzyme activities indicative of the Embden–Meyerhof–Parnas and pentose phosphate glycolytic pathways. As determined from labelling patterns, Streptomyces C5 apparently has a complete tricarboxylic acid cycle, but does not have a glyoxylate bypass pathway.
Influence de la cytochalasine A sur la composition de fractions subcellulaires d'hyphes en croissance du Mucor mucedo L. II. Composition des parois
Authors: Mougith Abdou Ahmed Abd El Razak El , Fonvieille Jean-Louis , Dargent Robert , Rami Jacques , Touzé-Soulet Jane-Marie
Published: May 2010

Walls of young hyphae of Mucor mucedo L. growing in the presence or absence of cytochalasin A were isolated and their chemical content determined. Cytochalasin A induced modified proportions of various monomers resulting in a reduction of the (neutral sugars + glucuronic acid)/glucosamine ratio. The walls contained less proteins but more chitin–chitosan and phosphate. These modifications are discussed in relation to ultrastructural changes described previously.
Repression of xylose utilization by glucose in xylose-fermenting yeasts
Authors: Panchal Chandra J. , Bast Lynda , Russell Inge , Stewart Graham G.
Published: May 2010

The xylose-fermenting yeasts Pichia stipitis, Candida steatolytica, and Candida shehatae were subjected to fermentations in synthetic media containing mixtures of glucose and xylose. In all cases, repression of xylose uptake by glucose was observed, although the extent of repression was different with each yeast. While Candida shehatae was found to utilize xylose effectively in the presence of approximately 5% (w/v) glucose, Candida steatolytica could only utilize xylose when the glucose concentration was below 3% (w/v), and Pichia stipitis required the glucose concentration in the medium to be below 2% (w/v) before significant xylose utilization occurred.
Ultrastructure and composition of the conidial wall of Cladosporium cladosporioides
Authors: Latgé J. -P. , Bouziane H. , Diaquin M.
Published: May 2010

Transmission electron microscopy revealed that the conidial wall of Cladosporium cladosporioides was constituted of an electron-lucent inner layer and an electron-dense outer layer. The conidial surface is covered by rodlet fascicles which can be removed by ultrasonication. Ultrastructurally, the 100 000 × g ultracentrifugation pellet of the ultrasonicated extract containing the rodlet layer appeared as an amorphous structure containing probably internal wall material anchoring the rodlet fascicles on the wall. The total conidial wall was essentially composed of β(1 → 3)glucans and melanin. Lipid, salt, and galactan represented the main components of the 100 000 × g ultracentrifugation pellet of the ultrasonicated extract. Cladosporium cladosporioides produced melanin via the pentaketide pathway. Tricyclazole inhibited melanin synthesis but did not interfere with allergen production. This suggests that the wall components associated with melanin are not allergenic factors.