bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of aBacteroidesspecies from human intestine that degrades glycosaminoglycans
Authors: Ahn Mi Young , Shin Kuk Hyun , Kim Dong-Hyun , Jung Eun-Ah , Toida Toshihiko , Linhardt Robert J , Kim Yeong Shik
Published: April 2011

Polysaccharide lyases that can degrade glycosaminoglycans (GAGs) were identified in an anaerobic strain living in the human intestine. The strain was isolated from the stool of a healthy male and identified as Bacteroides sp. strain HJ-15. A detailed taxonomical study indicated the species is a strain of Bacteroides stercoris. The isolate was cultured and the polysaccharide lyase activity was partially purified. This enzyme preparation could act on GAGs containing either glucosamine or galactosamine suggesting the presence of both heparinases and chondroitinases. Various GAGs were incubated with the partially purified enzyme and the products formed were analyzed by strong anion-exchange high performance liquid chromatography and proton nuclear magnetic resonance spectroscopy. These studies demonstrated the presence of at least two types of polysaccharide lyases: heparin lyase and chondroitin sulfate lyase. The eliminative mechanism of these lyase enzymes was confirmed through the isolation of unsaturated disaccharide products. The heparin lyase acted on both heparin and acharan sulfate, a GAG recently isolated from Achatina fulica. The Bacteroides chondroitin lyase, acted on chondroitin sulfates A, B (dermatan sulfate), and C, resembling chondroitin lyase ABC. The presence of a GAG-degrading organism in human intestine may pose problems for the effective oral administration of GAG drugs.Key words: Bacteroides stercoris, glycosaminoglycan, nuclear magnetic resonance spectroscopy, polysaccharide lyase, heparinase, chondroitinase.
Isolement et caractérisation chimique des lipopolysaccharides de type R dans une souche hypovirulente de Yersinia pestis
Authors: Minka S , Bruneteau M
Published: April 2011

The lipopolysaccharides LPS I and LPS II, isolated from the hypovirulent EV40 strain of Yersinia pestis, are composed only of type R lipopolysaccharides. This type consists of two forms, a and b, depending on their solubility pattern in a solvent mixture containing varying proportions of chloroform, methanol, hexane, and hydrochloric acid. LPS I consists of one subtype, RIb, while LPS II consists of two subtypes, RIIa and RIIb. Analysis by gel electrophoresis shows that the mass of these lipopolysaccharide forms are in the vicinity of 2000-3000 Da. The RIb and RIIb subtypes, which are found in the majority of lipopolysaccharide I and II fractions, are composed of ketoses and amines that are similar to those occurring in LPS I and LPS II. In contrast, the two subtypes RIIa and RIIb are different both in terms of the composition of lipid A and the extent of its substitution. Certain fractions of RIIa contain only lipid A and 3-deoxy-D-manno-octulosonic acid (KDO), while other fractions of RIIb possess a lipid A, which is not substituted by arabinose. The whole set of these R-type lipopolysaccharide forms are excellent models for the study of the role of the primary structure of the polysaccharide region, and for the effect of lipid A substitution on the biological activity of bacterial lipopolysaccharides.Key words: Yersinia pestis, hypovirulence, lipopolysaccharides, R type.[Journal translation]
Fungicidal properties, sterol binding, and proteolytic resistance of the synthetic peptide D4E1
Authors: De Lucca A J , Bland J M , Grimm C , Jacks T J , Cary J W , Jaynes J M , Cleveland T E , Walsh T J
Published: April 2011

The fungicidal properties of the synthetic peptide D4E1 were studied with nongerminated and germinating conidia of Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Fusarium moniliforme, and Fusarium oxysporum. The minimal lethal concentrations (MLC) needed to kill 100% of germinating conidia ofA. fumigatus, A. flavus, and A. niger were 12.5, 12.5, and 25 µM, respectively. The MLC value for nongerminated and germinating conidia of both Fusarium spp. was 3.0 µM. Except for A. fumigatus, D4E1 was inactive against the nongerminated conidia of the Aspergillus spp. Physicochemical studies showed D4E1 complexed with ergosterol, a sterol present in conidial walls. Cholesterol, present in nongerminated conidia of F. moniliforme, had a greater affinity for D4E1 than did ergosterol. D4E1 was more resistant to fungal and plant protease degradation than the natural peptide, cecropin A. These in vitro results suggest D4E1 is a candidate for transgenic expression in plants to enhance host resistance to fungal infection.Key words: peptides, fungicidal, Aspergillus spp., Fusarium spp., sterols.
Kinetic analyses of Biolog community profiles to detect changes in inoculum density and species diversity of river bacterial communities
Authors: Lawley Trevor , Bell Colin
Published: April 2011

The kinetics of response curves from Biolog community profiles for heterotrophic bacteria from a river in Nova Scotia, Canada have been analyzed to generate lag, slope, and asymptote parameters. The river water samples were treated with one of three supplements of Escherichia coli (in situ levels, 103CFU/mL, or 106CFU/mL) and one of five concentrations of chlorine (0, 1, 3, 5, or 7 ppm) to satisfy a full factorial design. The chlorine treatments decreased the inoculum density by up to 2 log values and decreased the species evenness. The E. coli supplements increased the inoculum density and decreased the species richness. Examination of the asymptotes did not reveal any significant effects owing to E. coli, but differences owing to the chlorine were detected. Analyses of the slopes showed a similar insignificance of the effects of E. coli and a lack of treatment effect owing to chlorine. The lag analyses also showed no significant E. coli effects, but showed a significant effect owing to chlorine. The discrepancy produced with the slope analysis (i.e., no chlorine effect) may represent an anomaly of the Biolog community approach. The use of lag phase was impaired because of the problem of infinite lags from wells that had no response, but a principle component analysis with a reduced set of substrates did suggest some influence of E. coli on the community profile. An examination of the substrates metabolized by the river water compared with pure E. coli revealed that the Biolog profiles of the river communities were not a simple summation of the component parts. In light of the lack of uniformity between these analyses, where the outcome depended on which parameter was used, caution is advised in interpreting Biolog community profiles on the basis of only one parameter.Key words: Biolog, chlorination, Escherichia coli, community, river, diversity.
Alterococcus agarolyticus, gen.nov., sp.nov., a halophilic thermophilic bacterium capable of agar degradation
Authors: Shieh Wung Yang , Jean Wen Dar
Published: April 2011

Five strains of facultatively anaerobic moderately thermophilic bacteria were isolated from two hot springs in the intertidal zone of Lutao, Taiwan. They produced extracellular agarase on agar medium, yielding reducing sugars and organic acids as the end products under either aerobic or anaerobic conditions. The growth temperature range was approximately 3858°C with an optimal temperature of about 48°C. The five strains tolerated a relatively narrow pH range from 7.0 to 8.5. They were Gram-negative halophiles growing optimally at 2.02.5% NaCl (ca. 0.340.43 M). They were capable of anaerobic growth by fermenting glucose and producing various organic acids such as butyrate, propionate, formate, lactate, and acetate. Cells grown in liquid medium were motile monotrichous cocci, normally 0.80.9 µm in diameter. They possessed saturated anteiso-15-carbon acid (anteiso-C15:0) as the most abundant cellular fatty acid (46.051.3 mo1%) and had G+C contents ranging from 65.5 to 67.0 mo1%. They are the first thermophiles found to degrade agar and also the first halophilic thermophilic bacteria known to be capable of both aerobic and anaerobic fermentative growth. These bacteria are considered to represent a new genus that we named Alterococcus, and Alterococcus agarolyticus is the type species. Key words: Alterococcus agarolyticus, thermophilic bacteria, halophilic bacteria, agar-degrading bacteria, fermentative bacteria.
Candida ipomoeae, a new yeast species related to large-spored Metschnikowia species
Authors: Lachance Marc-André , Rosa Carlos A , Starmer William T , Bowles Jane M
Published: April 2011

Numerous strains of an unusual asexual yeast species were isolated from flowers of morning glory (Ipomoea spp., Convolvulaceae) and associated drosophilids and sap beetles of the genus Conotelus sampled in Hawaii and in Brazil. The nutritional profile of this yeast is similar to those of Metschnikowia hawaiiensis and Metschnikowia continentalis, which share the same habitats. The cells are large, hydrophobic, and tend to remain attached after budding, causing the colonies on agar media to have a convoluted appearance, reminiscent of popcorn. The sequences of the D1/D2 domain of large subunit rDNAs of strains from three different localities confirmed that a single species is involved, and that it is related to large-spored Metschnikowia species. The type strain is UWO(PS)91-672.1 (CBS 8466).Key words: Candida ipomoeae, yeast, new species, rDNA.
Isolation and characterization of ACC deaminase genes from two different plant growth-promoting rhizobacteria
Authors: Shah Salehuzzaman , Li Jiping , Moffatt Barbara A , Glick Bernard R
Published: April 2011

We have recently proposed that one way that plant growth-promoting rhizobacteria (PGPR) stimulate plant growth is through the activity of the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, which causes a lowering of plant ethylene levels resulting in longer roots. As part of an effort to understand the role of this enzyme in PGPR, the genes for ACC deaminase from two PGPR, Enterobacter cloacae CAL2 and UW4, have been isolated. These genes are highly homologous to the ACC deaminase genes from Pseudomonas strains 6G5 and F17 and similar to the ACC deaminase gene from Pseudomonas sp. strain ACP. The region downstream (i.e., at the 3'-terminal end) of the strain UW4 ACC deaminase gene has a potential hairpin-like transcription termination site. The regions upstream of the strains UW4 and CAL2 ACC deaminase genes contain putative ribosome-binding sites; however, the promoter sequences have not yet been identified.

Southern hybridization experiments suggest that there is a single copy of the ACC deaminase gene in Enterobacter cloacae strains UW4 and CAL2 and that there may be several different types of ACC deaminase genes in different microbes. The cloned ACC deaminase gene can be expressed in Escherichia coli enabling this bacterium to grow on ACC as a sole source of nitrogen and confers upon both Escherichia coli and Pseudomonas spp. strains that are transformed with this gene the ability to promote the elongation of the roots of canola seedlings.Key words: plant growth-promoting rhizobacteria, PGPR, 1-aminocyclopropane-1-carboxylate, ACC, ACC deaminase, ethylene, soil bacteria.
Isolation and characterization of an Escherichia coli B mutant strain defective in uracil catabolism
Authors: West Thomas P
Published: April 2011

A reductive pathway of uracil catabolism was shown to be functioning in Escherichia coli B ATCC 11303 by virtue of thin-layer chromatographic and enzyme analyses. A mutant defective in uracil catabolism was isolated from this strain and subsequently characterized. The three enzyme activities associated with the reductive pathway of pyrimidine catabolism were detectable in the wild-type E. coli B cells, while the mutant strain was found to be deficient for dihydropyrimidine dehydrogenase activity. The dehydrogenase was shown to utilize NADPH as its nicotinamide cofactor. Growth of ATCC 11303 cells on uracil or glutamic acid instead of ammonium sulfate as a nitrogen source increased the reductive pathway enzyme activities. The mutant strain exhibited increased catabolic enzyme activities after growth on ammonium sulfate or glutamic acid.Key words: uracil catabolism, dihydropyrimidine dehydrogenase, reductive pathway, mutant, Escherichia coli.
Fungal melanins: a review
Authors: Butler M J , Day A W
Published: April 2011

The relationship of polyketide melanogenesis molecular biology to that of nonmelanin-producing pathways in a wide range of fungi and other organisms is discussed. Analytical methods and fundamental properties of melanins are discussed and fungal melanin properties are compared with those of animal and bacterial melanins. The enzymatic degradation of melanins by lignin peroxidases is described.Key words: fungal melanin, polyketide melanin, DHN melanin, melanin degradation, melanin properties, melanin analysis.
Isolation of a methanogenic bacterium, Methanosarcina sp. strain FR, for its ability to degrade high concentrations of perchloroethylene
Authors: Cabirol Nathalie , Villemur Richard , Perrier Joseph , Jacob François , Fouillet Bruno , Chambon Paul
Published: April 2011

Tetrachloroethylene (PCE) is a toxic compound essentially used as a degreasing and dry-cleaning solvent. A methanogenic and sulfate-reducing consortium that dechlorinates and mineralizes high concentrations of PCE was derived from anaerobically digested sludge obtained from a waste water treatment plant (Bourg-en-Bresse, France). A methanogenic bacterium, strain FR, was isolated from this acclimated consortium. On the basis of morphological and physiological characteristics, strain FR was classified in the genus of Methanosarcina. Phylogeny analysis with the 16S rRNA gene sequence revealed that strain FR is highly related to Methanosarcina mazei and Methanosarcina frisia (99.6 and 99.5% identity, respectively). High concentrations (50-87 μM) of PCE were completely dechlorinated by strain FR cultures at the rate of 76 nM·mg protein-1·day-1. PCE dechlorination produced a nonidentified compound. The tracer experiments with [13C]PCE revealed that the product was nonchlorinated. Dechlorination of PCE to trichloroethylene was still active in the presence of boiled cell extract of the strain FR. However, no further dechlorination was observed. This result suggests that a cofactor rather than an enzymatic system is responsible for the first dechlorination of PCE. Dechlorination-active fractions purified from cell extracts on a XAD-4 column revealed the presence of F420, F430, and cobamides cofactors. This is the first report of the isolation of a methanogenic bacterium with the ability to dechlorinate high concentrations of PCE to a nonchlorinated product.Key words: dechlorination, Methanosarcina, tetrachloroethylene.
The influence of bacterial inoculants on the microbial ecology of aerobic spoilage of barley silage
Authors: Inglis G D , Yanke L J , Kawchuk L M , McAllister T A
Published: April 2011

The aerobic decomposition of barley silage treated with two inoculants (LacA and LacB) containing mixtures of Lactobacillus plantarum and Enterococcus faecium was investigated over a 28-day period. Initially, yeast and bacterial populations were larger in silage inoculated with LacA than in silage treated with LacB or water alone (control). Differences in the succession of yeasts in silage treated with LacA were observed relative to the other two treatments. From silage treatment with LacA, Issatchenkia orientalis was the most prevalent yeast taxon over all of the sample times, and the filamentous fungus Microascus brevicaulis was also frequently isolated at later sample dates ([Formula: see text]14 days). In contrast, Saccharomyces exiguus was the most prominent yeast recovered from silage treated with LacB and water alone on days 2 and 4, although it was supplanted by I. orientalis at later sample times. Successional trends of bacteria were similar for all three treatments. Lactobacillus spp. were initially the most prevalent bacteria isolated, followed by Bacillus spp. (primarily Bacillus pumilus). However, the onset of Bacillus spp. prominence was faster in LacA silage, and Klebsiella planticola was frequently recovered at later sample times ([Formula: see text]14 days). More filamentous fungi were recovered from LacA silage on media containing carboxylmethylcellulose, pectin, or xylan. The most commonly isolated taxa were Absidia sp., Aspergillus flavus, Aspergillus fumigatus, Byssochlamys nivea, Monascus ruber, Penicillium brevicompactum, Pseudoallescheria boydii, and M. brevicaulis. The results of this study indicated that the two bacterial inoculants incorporated into barley at the time of ensilage affected the microbial ecology of silage decomposition following exposure to air. However, neither of the microbial inoculants effectively delayed aerobic spoilage of barley silage, and the rate of decomposition of silage treated with one of the inoculants (LacA) was actually enhanced.Key words: stability, yeasts, bacteria, fungi, Lactobacillus plantarum, Enterococcus faecium.
Oxidation of inorganic sulfur compounds: Chemical and enzymatic reactions
Authors: Suzuki Isamu
Published: April 2011

Microbial oxidation of inorganic sulfur compounds is governed by both chemical and enzymatic reactions. It is therefore essential to understand reactions possible in chemistry when we consider enzymatic reactions. Various oxidation states of sulfur atoms in inorganic sulfur compounds and chemical oxidation reactions as well as nucleophilic cleavage of sulfur-sulfur bonds are discussed. The scheme of enzymatic oxidation of sulfur compounds with S2-→> S0→> SO32-→> SO42-as the main oxidation pathway is discussed with thiosulfate and polythionates leading into the main pathway for complete oxidation to sulfate. Enzymatic reactions are related to chemical reactions and the use of inhibitors for S0→> SO32-and SO32-→> SO42-is discussed for analyzing and establishing reaction stoichiometries. The proposed pathway is supported by a variety of evidence in many different microorganisms including some genetic evidence if the oxidation steps include all the systems irrespective of oxidizing agents (O2, Fe3+, cytochromes etc.).Key words: sulfur, oxidation, chemical, enzymatic, reactions.
Fate ofCryptosporidiumoocysts,Giardiacysts, and microbial indicators during wastewater treatment and anaerobic sludge digestion
Authors: Chauret Christian , Springthorpe Susan , Sattar Syed
Published: April 2011

The extent of reduction in selected microorganisms was tested during both aerobic wastewater treatment and anaerobic digestion of sludge at the wastewater treatment plant in Ottawa to compare the removal of two encysted pathogenic protozoa with that of microbial indicators. Samples collected included the raw wastewater, the primary effluent, the treated wastewater, the mixed sludge, the decanted liquor, and the cake. All of the raw sewage samples were positive for Cryptosporidium oocysts and Giardia cysts, as well as for the other microorganisms tested. During aerobic wastewater treatment (excluding the anaerobic sludge digestion), Cryptosporidium and Giardia were reduced by 2.96 log10and 1.40 log10, respectively. Clostridium perfringens spores, Clostridium perfringens total counts, somatic coliphages, and heterotrophic bacteria were reduced by approximately 0.89 log10, 0.96 log10, 1.58 log10, and 2.02 log10, respectively. All of the other microorganisms were reduced by at least 3.53 log10. Sludge samples from the plant were found to contain variable densities of microorganisms. Variability in microbial concentrations was sometimes great between samples, stressing the importance of collecting a large number of samples over a long period of time. In all cases, the bacterial concentrations in the cake (dewatered biosolids) samples were high even if reductions in numbers were observed with some bacteria. During anaerobic sludge digestion, no statistically significant reduction was observed for Clostridium perfringens, Enterococcus sp., Cryptosporidium oocysts, and Giardia cysts. A 1-2 log10reduction was observed with fecal coliforms and heterotrophic bacteria. However, the method utilized to detect the protozoan parasites does not differentiate between viable and nonviable organisms. On the other hand, total coliforms and somatic coliphages were reduced by 0.35 log10and 0.09 log10, respectively. These results demonstrate the relative persistence of the protozoa in sewage sludge during wastewater treatment.Key words: Cryptosporidium, Giardia, indicators, wastewater, sludge.
Degradation of morpholine, piperidine, and pyrrolidine by mycobacteria: evidences for the involvement of a cytochrome P450
Authors: Poupin P , Godon J J , Zumstein E , Truffaut N
Published: April 2011

Nine bacterial strains that grew on morpholine and pyrrolidine as sole carbon, nitrogen, and energy sources were isolated from three different environments with no known morpholine contamination. One of these strains could also degrade piperidine. These bacteria were identified as Mycobacterium strains. A phylogenetic analysis based on the partial 16S rDNA sequences indicated that the isolated strains clustered within the fast growing group of mycobacteria. When the above-mentioned cyclic amines were used as growth substrates, the synthesis of a soluble cytochrome P450 was induced in all these bacteria. Other laboratory strains, Mycobacterium fortuitum and Mycobacterium smegmatis mc2155, were tested for their abilities to degrade morpholine. Neither of them degraded morpholine but could use pyrrolidine and piperidine. The growth of M. fortuitum and M. smegmatis mc2155 on these compounds involved a soluble cytochrome P450, suggesting that mycobacterial strains are naturally able to use pyrrolidine and have developed a similar enzymatic pathway to metabolize this amine.Key words: mycobacteria, morpholine, piperidine, pyrrolidine, cytochrome P450.
Construction of a genomic map ofMoraxella (Branhamella) catarrhalisATCC 25238 and physical mapping of virulence-associated genes
Authors: Nguyen K T , Hansen E J , Farinha M A
Published: April 2011

A physical genome map of the Moraxella catarrhalis type strain (ATCC 25238) has been constructed using pulsed field gel electrophoresis. Macrorestriction analyses of the genome of M. catarrhalis were performed by digestion with the restriction enzymes SmaI, NotI, and RsrII, which cleave the single circular chromosome into 9, 10, and 6 fragments, respectively. The chromosomal fragments generated by pulsed field gel electrophoresis were converted to a linkage map utilizing a combination of partial digestions, and cross-hybridizations. Moraxella catarrhalis, like a number of other respiratory pathogens, has a relatively small genome estimated at 1750 kilobase pairs or about 40% of the size of the Escherichia coli genome. The locations of the four ribosomal RNA operons (rrnLS) were determined by Southern hybridization and by digestion with I-CeuI endonuclease. A number of genes involved in virulence have been placed onto the physical map by Southern hybridization including those encoding the predominant outer-membrane proteins and the chromosomal gene encoding beta-lactamase.Key words: Moraxella catarrhalis, physical map, genome analysis, pulsed-field gel electrophoresis, virulence.
Diversification ofPseudomonas corrugata2140 produces new phenotypes altered in GC-FAME, BIOLOG, and in vitro inhibition profiles and taxonomic identification
Authors: Barnett S J , Alami Y , Singleton I , Ryder M H
Published: April 2011

Bacteria are known to rapidly produce new phenotypes, but it is unclear how phenotype "plasticity" relates to studies on the population ecology of bacteria in complex environments. We characterised a collection of 14 spontaneous phenotype variants, derived from in vitro and in vivo cultures (wheat roots) of Pseudomonas corrugata 2140, using fatty acid methyl ester profiles (GC-FAME), carbon substrate utilisation (BIOLOG), and in vitro inhibition against seven soil microorganisms. All three phenotype profiles indicated marked differences between some variants and the parent isolate. Some variant types were classified taxonomically by GC-FAME as different species to their wild-type parent, and up to a Euclidian distance of 11 from their parent. Taxonomic identification by the BIOLOG assay was more consistent; however, use of 22 carbon sources were altered (lost or gained) in one or more variants. All variant types had a reduced ability to inhibit one or more test organisms, depending on the variant and test organism. Hierarchical cluster analysis of variants using GC-FAME, BIOLOG, and inhibition profiles produced different groupings. The ability of variants to cross taxonomic boundaries specified by the GC-FAME and BIOLOG libraries at the species level has implications for both taxonomy and the ecological study of bacterial communities.Key words: Pseudomonas corrugata, variants, phenotype plasticity, FAME, BIOLOG.
Regulated expression of HIV-1 Rev function in mammalian cell lines
Authors: Swenarchuk Lauren , Harakidas Penelope , Cochrane Alan
Published: April 2011

In order to facilitate further investigation of Rev function, we have generated two systems for the inducible expression of Rev in mammalian cell lines (HeLa and U937) using either a tetracycline-regulated promoter or fusion of Rev to a modified form of the hormone binding domain of the estrogen receptor. In the case of the fusion of Rev to the modified hormone binding domain of the estrogen receptor, we demonstrated induction of Rev function in response to tamoxifen administration to levels comparable to that of the unmodified Rev protein. Subsequently, U937 lines were generated that retained the observed pattern of hormone-dependent function of the Rev fusion protein. In the case of the tetracycline-regulated system, cell lines (both HeLa and U937) were generated that displayed tight regulation of Rev. In the case of the HeLa cell lines, they were used for the subsequent generation of stable cell lines expressing either HIV-1 env or chloramphenicol acetyl transferase (CAT) in a Rev-dependent fashion. Using the latter cell lines, we demonstrate the ability to control Rev expression over a broad concentration range and find that, as soon as Rev expression is detectable, induction of Rev-dependent gene expression is also observed.Key words: Rev, tamoxifen, tetracyline-regulated transcription, Rev function, threshold effects.
RecombinantPseudomonasexoenzyme S and exoenzyme S fromPseudomonas aeruginosaDG1 share the ability to stimulate T lymphocyte proliferation
Authors: Bruno Tony F , Woods Donald E , Storey Douglas G , Mody Christopher H
Published: April 2011

Exoenzyme S from P. aeruginosa DG1 and recombinant exoenzyme S derived from strain 388 have distinct characteristics, which has led to a controversy about their homology and their pathophysiologic consequences. We have been investigating the ability of exoenzyme S to activate T lymphocytes, and therefore performed studies to determine whether exoenzyme S from P. aeruginosa DG1 and recombinant exoenzyme S derived from strain 388 and expressed in Pseudomonas aeruginosa PA103 or in E. coli BL21(DE3), could induce T lymphocyte activation and proliferation. Both preparations were able to activate T cells and induce lymphocyte proliferation at similar levels as measured by flow cytometry of surface-activation markers and DNA synthesis, respectively. Further, a monoclonal antibody raised against exoenzyme S from strain DG1 partially neutralized T cell activation induced by recombinant exoenzyme S and bound to it in an immunoblot suggesting that the epitope responsible for T cell activation is shared by exoenzyme S from strain DG1 and recombinant exoenzyme S. These data suggest that the two different preparations of exoenzyme S, despite biochemical differences, share the characteristic that is responsible for T lymphocyte activation.Key words: exoenzyme S, Pseudomonas aeruginosa, T lymphocyte, cystic fibrosis.
Transformation of the entomopathogenic fungusMetarhizium flavovirideto high resistance to benomyl
Authors: Furlaneto Marcia Cristina , Gonzalez Paião Fernanda , Gisele da S. Pinto Fabiana , Fungaro Maria Helena Pelegrinelli
Published: April 2011

A Brazilian isolate of Metarhizium flavoviride, which has been developed as a biocontrol agent against the grasshopper Rhammatocerus schistocercoides, was stably transformed to be resistant to benomyl (beta-tubulin gene). Highly resistant transformants were obtained which grew in benomyl concentrations greater than 30 times (200 µg mL-1) the concentration that inhibits wild type proliferation. These transformants were mitotically stable after 20 successive transfers on non-selective media. No significant differences in conidia yield were observed between stably transformed strains and wild type (CG423). Chymoelastase (Pr1) secretion was greater in some transformants than in the wild type. In the presence of benomyl, appressoria differentiation occurred at similar rates in CG423 and transformants. However, the percentage of conidial germination in the transformants was higher than in the wild type, indicating the potential use of these transformants along with benomyl. Additionally, the resistance levels of the transformants observed in the present study demonstrate the potential use of these transformants for assessing the persistence of a particular isolate in fields without this fungicide.Key words: Metarhizium flavoviride, genetic transformation, benomyl resistance, biocontrol.
Removal of silver from photographic wastewater effluent using Acinetobacter baumannii BL54
Authors: Shakibaie Mohammad Reza , Kapadnis Balu Parnab , Dhakephalker Pershant , Chopade Balu Ananda
Published: April 2011

Acinetobacter baumannii BL54, a silver (Ag) resistant micro-organism was isolated from clinical samples collected at the Armed Forces Medical College hospital in Pune, India. The strain BL54 removed a high quantity of silver (2.85 mg/g biomass) from photographic wastewater effluent. Treatment of the cells with 10 mM EDTA or agitating the culture did not affect the removal process, while altering pH of the wastewater or pre-treating the cells with 0.5 mM 2,4-dinitrophenol (DNP), 20 μM N,N'-dicyclohexylcarbodiimide (DCC), 25 μg/mL cefotaxime, and polymyxin-B resulted in considerable decrease in removal of silver by the organism. Dead cells, or a Ags plasmid-cured derivative (BL54.1) removed little silver, which was mainly surface bound. The results, compared with accumulation of Ag by a sensitive culture of Escherichia coli K12 J53.2, suggest that A. baumannii BL54 has good potential for bioremediation of silver from photographic wastewater effluents. Key words: Acinetobacter, silver resistance, silver removal.
A simple rapid procedure for obtaining axenic cultures from monoxenic cultures of myxomycete plasmodia
Authors: Balaji S , Sujatha A , Kalyanasundaram I
Published: April 2011

Axenic culture of myxomycete plasmodia has been attempted from time to time by various authors, but with very little success. From over 500 known species of myxomycetes, fewer than 20 species have been reported in axenic culture to date, including axenic myxamoebal cultures. In these cultures, the plasmodia required either complex media, or a killed bacterial supplement for growth. Furthermore, the time required for attaining the axenic state varied from several months to years. In the present study, a simple, rapid procedure has been developed to render monoxenic plasmodial cultures axenic. This procedure is based on our discovery that plasmodia have certain unusual substrate preferences that are inhibitory to the associated bacteria using Physarella oblonga as a model. The presence or absence of the bacteria could be ascertained through incubation in four different bacteriological media and by the use of a differential staining technique.Key words: myxomycetes, axenic culture, hydrocarbon utilization, bacterial associates.
Diversity of culturable heterotrophic aerobic bacteria in pristine stream bed sediments
Authors: Halda-Alija L , Johnston T C
Published: April 2011

More than 900 culturable, heterotrophic aerobic isolates were obtained from the sediments of a forested, pristine stream and analyzed using three classical microbiological tests: API 20E, amplified ribosomal DNA restriction analysis (ARDRA), and fatty acid analysis. Gram-negative bacteria comprised most of the heterotrophic aerobic isolates (66.7%), similar to other oligotrophic environments. The isolates were assigned to the genus level as Pseudomonas, Flavobacterium, Micrococcus, Bacillus, Chromobacterium, Acinetobacter, Alcaligenes, Aeromonas, Methylobacterium, Enterobacter, Corynebacterium, and Sporolactobacillus. Genotypic analysis by ARDRA facilitated the comparison among strains within Pseudomonas, Bacillus, and Enterobacter groups. Temperature and predation may influence the survival of bacteria during seasons, as shown previously by others. Our results showed that the number of heterotrophic aerobic bacteria, especially Enterobacter, Alcaligenes, and Aeromonas, and Gram-positive bacteria, decreased in winter compared to summer conditions.Key words: stream, heterotrophic aerobic bacteria, ARDRA.
Specific mucosal immunity in the pathophysiology of bacterial prostatitis in a rat model
Authors: Ceri H , Schmidt S , Olson M E , Nickel J C , Benediktsson H
Published: April 2011

Mucosal immunity was established in the rat prostate by stimulating the common mucosal system through serosal exposure of formalin-killed Escherichia coli. Immunized but not sham-immunized rats developed bacterial specific IgG and IgA in prostatic fluid, and IgA in urine. Immunized (n = 21) and sham-immunized control rats (n = 30) were challenged by transurethral injection of E. coli into the prostate ducts. Mortality, gross and microscopic pathology, tissue bacterial counts, bacterial associated immunoglobulins, and antibody titers in serum and urine were assessed at 7 days following the challenge. Increased E. coli specific immunoglobulin titers were seen in immunized rats, and E. coli, but not Proteus, found in the prostates of immunized animals were coated with IgG and IgA. Immunization protected against toxaemia and septicemia, seen as a rare complication of acute prostatitis, but did not protect against acute prostatitis, nor alter the degree of tissue damage seen in the rat model.Key words: prostatitis, mucosal immunity, rat model.
Some probiotic properties of chicken lactobacilli
Authors: Gusils Carlos , González Silvia N , Oliver G
Published: April 2011

The beneficial effect of lactobacilli has been attributed to their ability to colonize human and animal gastrointestinal tracts. In this work, adhesion assays with three lactobacillus strains and intestinal fragments obtained from chickens were assessed. Lactobacillus animalis and L. fermentum were able to adhere to three kinds of epithelial cells (crop, small and large intestines) with predominance to small intestine. Among the strains considered, L. fermentum subsp. cellobiosus showed the lowest and L. animalis the highest adhesion ability. Scanning electron microphotographs showing L. animalis and L. fermentum adhering to intestinal cells were obtained. The characterization of L. animalis adhesion indicated that lectin-like structure of this strain has glucose/mannose as specific sugars of binding. However, a calcium requirement was not observed. The adhesion of L. fermentum was reduced by addition of sialic acid or mannose (P < 0.01). These carbohydrates can be involved in the interaction between adhesin and epithelial surface. In this case, the dependence on bivalent cations was demonstrated. Lactobacillus fermentum was effective in reducing the attachment of Salmonella pullorum by 77%, while L. animalis was able to inhibit (90%, 88%, and 78%) the adhesion of S. pullorum, S. enteritidis, and S. gallinarum to host-specific epithelial fragments respectively. Our results from this in vitro model suggest that these lactobacilli are able to block the binding sites for Salmonella adhesion.Key words: lactobacilli, lectin-like structures, poultry adhesion, probiotic properties.
Isolation and characterization of mini-Tn10lipopolysaccharide mutants ofActinobacillus pleuropneumoniaeserotype 1
Authors: Rioux Stéphane , Galarneau Catherine , Harel Josée , Frey Joachim , Nicolet Jacques , Kobisch Marylène , Dubreuil J Daniel , Jacques Mario
Published: April 2011

Lipopolysaccharide (LPS) has previously been identified as the major adhesin of Actinobacillus pleuropneumoniae involved in adherence to porcine respiratory tract cells. The purpose of the present study was to isolate and characterize mutants in LPS biosynthesis by using a mini-Tn10 transposon mutagenesis system. Seven mutants appeared to possess a rough LPS (among which two had similar Southern blot profiles) while one mutant (#5.1) expressed the high-molecular-mass LPS, but as visualized by Tricine SDS-PAGE, showed an additional band in the core-lipid A region. The LPS mutants showed sensitivity to pig serum to various degrees, while the parent strain was serum-resistant. Use of piglet frozen tracheal sections indicated that, surprisingly, the rough LPS mutants adhered similarly or in greater numbers than the parent strain. However, the LPS mutant #5.1 adhered significantly less than the parent strain and was also less virulent in pigs. The gene affected by mini-Tn10 in LPS mutant #5.1 is galU, the structural gene for UTP-α-D-glucose-1-phosphate uridylyltransferase, involved in LPS core biosynthesis. Complementation analysis confirmed that the phenotypic characteristics of LPS mutant #5.1 are the result of the inactivation of the galU gene. Our data suggest that although the presence of O-antigen does not seem to be essential, an intact core-lipid A region might be required for adherence of A. pleuropneumoniae to porcine respiratory tract cells. To the best of our knowledge, these mutants represent the first isogenic mutants of A. pleuropneumoniae defective in LPS biosynthetic genes.Key words: Actinobacillus pleuropneumoniae, lipopolysaccharides, mutant, adherence, virulence.
Construction of an equalized cDNA library fromColletotrichum lagenariumand its application to the isolation of differentially expressed genes
Authors: Inagaki Atsuko , Takano Yoshitaka , Kubo Yasuyuki , Mise Kazuyuki , Furusawa Iwao
Published: April 2011

To establish an efficient screening system for differentially expressed genes of a phytopathogenic fungus Colletotrichum lagenarium, we constructed an equalized (normalized) cDNA library from C. lagenarium and used this library for differential screening. For the isolation of genes involved in infection-related developments of conidia, conidia undergoing appressorium differentiation were selected as the source of materials for construction of the cDNA library. The equalization of cDNA was performed twice using a kinetic method, and the products were cloned into a plasmid vector. Colony hybridization with nine probes of different abundance showed a reduction in abundance variation from at least 276-fold in the original library to 10-fold in the equalized cDNA library, which demonstrated that the cDNA was successfully equalized. By differential hybridization of 1900 cDNA clones in the equalized cDNA library and RNA blot analysis of candidate clones, we identified 11 independent cDNA clones, designated CAD1 through CAD11, that were expressed in appressorium-differentiating conidia, but not in vegetative mycelia. The transcripts of CAD1 and CAD2 hardly accumulated in preincubated conidia, whereas those of CAD3 and CAD4 accumulated highly and slightly, respectively. The amount of the four CAD transcripts increased at the early stage of the appressorium formation process. Sequence analysis of CAD1 revealed that CAD1 would encode for 101 amino acid polypeptides, which showed homology to metallothioneins. Deduced amino acid sequence of CAD2 would encode 278 amino acid polypeptides, and showed high homology to genes in aflatoxin, and sterigmatocystin gene clusters of Aspergillus parasiticus and A. nidulans, respectively. Key words: equalized cDNA library, differential screening, Colletotrichum lagenarium, appressorium formation, CAD genes.
Defining a novel domain of staphylococcal toxic shock syndrome toxin-1 critical for major histocompatibility complex class II binding, superantigenic activity, and lethality
Authors: Kum Winnie WS , Laupland Kevin B , Chow Anthony W
Published: April 2011

Staphylococcal toxic shock syndrome toxin-1 (TSST-1) is implicated in the pathogenesis of superantigen-mediated shock. We previously identified TSST-1 residues G31/S32 to be important for major histocompatibility complex (MHC) class II binding, as well as superantigenic and lethal activities. However, the site-directed TSST-1 mutant toxin, G31R, could still induce mitogenesis and low-level TNFalpha secretion, suggesting that additional MHC class II binding sites other than G31/S32 may exist. In the current study, a TSST-1-neutralizing monoclonal antibody, MAb5, was found to inhibit TSST-1 binding to human peripheral blood mononuclear cells, neutralize TSST-1-induced mitogenesis and cytokine secretion, and protect against TSST-1-induced lethality in vivo. Epitope mapping revealed that MAb5 bound to TSST-1 residues 51-56 (T(51-56);51YYSPAF56). Peptide T(51-56) was synthesized and found to also inhibit TSST-1 binding to human monocytes as well as TSST-1-induced mitogenesis, cytokine secretion, and lethality in vivo. This T(51-56) epitope, located within the beta3/beta4 loop, and the previously identified G31/S32 epitope, within the beta1/beta2 loop of TSST-1, are separated within the primary sequence, but spatially juxtaposed to each other. Collectively, these findings suggest that a discontinuous epitope comprising of regions within both the beta1/beta2 and beta3/beta4 loops, are critical for MHC class II binding, and the consequent superantigenic and lethal activities of TSST-1.
Adhesion to hyphal matrix and antifungal activity ofPseudomonasstrains isolated fromTuber borchiiascocarps
Authors: Sbrana C , Bagnoli G , Bedini S , Filippi C , Giovannetti M , Nuti M P
Published: April 2011

Pseudomonas spp. isolates from Tuber borchii ascocarps, known to be able to produce phytoregulatory and biocontrol substances in pure culture, were used to perform studies on their possible physiological role in nature. Antimycotic activity was confirmed against fungal contaminants isolated from the ascocarps, suggesting that populations associated with Tuber borchii fruit bodies may play a role in the maintenance of ascocarp health. Fifty-five percent of strains tested were also able to release metabolites which affected T. borchii mycelial growth and morphogenesis in culture. On the contrary, growth of the arbuscular mycorrhizal fungus Glomus mosseae and the ectomycorrhizal fungus Laccaria bicolor, putative competitors of Tuber for mycorrhizal infection sites on roots, was not influenced by the presence of any bacterial strain. The possibility that these bacteria, which show antifungal activity and fungal growth modulation activities, might be incorporated in the developing ascocarp by means of their preferential adhesion to Tuber mycelium is discussed.Key words: Tuber borchii, associated bacteria, Pseudomonas spp., biocontrol, adhesion.
Nutritional requirements of Xylella fastidiosa, which causes Pierce's disease in grapes
Authors: Chang C J , Donaldson R C
Published: April 2011

A defined medium (XF-26) containing 3 inorganic salts, 2 tricarboxylic acids, 17 amino acids, potato starch, phenol red, and agar was used as the starting point for the study. Deletions of one or more ingredients were performed to prepare various media. A medium was considered able to support growth of Xylella fastidiosa strains responsible for Pierce's disease in grapes, only after 10 serial passages had been completed. Of 3 inorganic salts, K2HPO4 and MgSO4·7H2O were essential, and (NH4)2HPO4 was nonessential for growth. Of the Krebs cycle intermediates, all (citrate, alpha-ketoglutarate, succinate, fumarate, malate, and oxaloacetate) but isocitrate supported growth of cultivated strains, whereas only citrate alone or citrate plus succinate supported the primary isolation of PD bacterium. Of 17 amino acids, 6 uncharged polar R groups (asparagine, cysteine, glutamine, glycine, serine, and threonine) supported growth, whereas 8 nonpolar R groups (alanine, isoleucine, leucine, methionine, phenylalanine, proline, tryptophan, and valine) or 3 positively charged polar groups (arginine, histidine, and lysine) did not. Starch proved to be nonessential.Key words: Xylella fastidiosa, nutritional requirements.
Comparative evaluation of conjugate vaccines in theHaemophilus influenzaeinfection model
Authors: Miyazaki Shuichi , Shintani Miharu , Matsumoto Tetsuya , Tateda Kazuhiro , Yamaguchi Keizo
Published: April 2011

We used a murine model of Haemophilus influenzae type b (Hib) infection to analyze the immunologic response to two commercially available PRP conjugate vaccines (HbOC, PRP-T). The mortality rate in mice infected with a large dose of the bacteria after vaccination with HbOC or PRP-T at two and three doses was significantly lower than in non-vaccinated mice and mice vaccinated by one dose. Furthermore, for infections caused by a small bacterial dose, the mortality rate in mice vaccinated with one, two, or three doses was significantly lower than in non-vaccinated mice. The induction level of anti-PRP antibodies, especially IgG, in serum of mice vaccinated by two or three doses was higher than in those vaccinated with a single dose. Our results indicate that the dose of vaccine influences its efficacy in protecting against Hib infection. Our results also showed a lack of difference between two different PRP conjugate vaccines.
Development of a xylitol biosensor composed of xylitol dehydrogenase and diaphorase
Authors: Takamizawa Kazuhiro , Uchida Shoji , Hatsu Masahiro , Suzuki Tohru , Kawai Keiichi
Published: April 2011

In preparation for the development of a xylitol biosensor, the xylitol dehydrogenase of Candida tropicalis IFO 0618 was partially purified and characterized. The optimal pH and temperature of the xylitol dehydrogenase were pH 8.0 and 50°C, respectively. Of the various alcohols tested, xylitol was the most rapidly oxidized, with sorbitol and ribitol being reduced at 65% and 58% of the xylitol rate. The enzyme was completely inactive on arabitol, xylose, glucose, glycerol, and ethanol. The enzyme's xylitol oxidation favored the use of NAD+(7.9 U/mg) over NADP+(0.2 U/mg) as electron acceptor, while the reverse reaction, D-xylulose reduction, favored NADPH (7.7 U/mg) over NADH (0.2 U/mg) as electron donor. The Kmvalues for xylitol and NAD+were 49.8 mM and 38.2 µM, respectively. For the generation of the xylitol biosensor, the above xylitol dehydrogenase and a diaphorase were immobilized on bromocyan-activated sephallose. The gel was then attached on a dissolved oxygen electrode. In the presence of vitamin K3, NAD+and phosphate buffer, the biosensor recorded a linear response to xylitol concentration up to 3 mM. The reaction was stable after 15 min. When the biosensor was applied to a flow injection system, optimal operation pH and temperature were 8.0 and 30°C, respectively. The strengths and limitations of the xylitol biosensor are its high affinity for NAD+, slow reaction time, narrow linear range of detection, and moderate affinity for xylitol.Key words: xylitol, xylitol dehydrogenase, biosensor, Candida tropicalis.