bluuebunny/crossref_metadata_2025 huggingface dataset:
Antibiotic resistance among predominant Salmonella serovars and phagovars in Canada
Authors: Duck P. D. , Dillon J. R. , Lior H. , Eidus L.
Published: April 2010

The antibiotic susceptibility of 2609 Salmonella isolates, collected during the period 1975–1976, was tested and the relationships between antibiotic-resistance pattern, source of isolation, and serovar and phagovar were determined. Of 95 serovars examined, 40 were sensitive to all of the antibiotics tested. Salmonella typhimurium was the major contributor to multiple resistance from both human and non-human sources.Multiply resistant strains were not found from animal feed sources and, in addition, S. typhimurium, one of the most predominant serovars, was found in every source but animal feeds.In comparing phagovar with resistance patterns, certain correlations were found. Greater than 90% of phagovar 10 was sensitive to all antibiotics tested whereas over 80% of phagovars 3-aerogenic, 92, and 123 were multiply resistant.
Characterization of bacteriophage CP1, an organic solvent sensitive phage associated with Pseudomonas cepacia
Authors: Cihlar R. L. , Lessie T. G. , Holt S. C.
Published: April 2010

Pseudomonas cepacia strain 249 has been found to harbor an organic solvent sensitive phage, CP1, which is active on other P. cepacia strains. The efficiency of plating of CP1 was dependent upon the strain on which it was propagated and the strain used as indicator, implying the operation of host restriction and modification systems in certain of the strains. Strain 383 which was used routinely for propagation of CP1 appears to lack such systems. To obtain high-titer lysates it was important to add EDTA to the infected cultures at the onset of lysis to block attachment of phage particles to cell debris. CP1 possesses a distinct head (55 nm in diameter) and a broad contractile tail (15 × 145 nm). Fluorescent staining of phage preparations with acridine orange indicated that CP1 contains double-stranded DNA. CP1 particles contained about 5 × 10−17 g each of protein and DNA for a total particle weight of 10−16 g. The apparent molecular weight of CP1 DNA estimated from its sedimentation behavior and the particle content of DNA was about 3 × 107. Thermal-denaturation studies indicated that the G + C content of CP1 DNA (65%) was lower than that of DNA of its P. cepacia host (71% G + C). The mechanism of inactivation of CP1 by chloroform appears to be related to tail contraction caused by this agent. An atypical reverse contraction of the tail sheath was noted in about 45% of the inactivated particles. No phospholipid was detected in purified preparations of CP1 (<4 × 10−19 g/PFU). The results suggest that inactivation of CP1 by organic solvents involves alteration of a component (presumably a protein) of the phage tail.
Survival of microbial films in the microwave oven
Authors: Page William J. , Martin Wendy G.
Published: April 2010

Air-dried films of Escherichia coli, Saccharomyces cerevisiae, and Bacillus subtilis spores on membrane filters, exposed to 10 min full power (650 W, 2450 MHz) irradiation in a Toshiba model ER776BT microwave oven, showed a 5-, 2-, and 0-log reduction of viable organisms respectively. Suspensions of cells or spores in phosphate buffer treated under similar conditions showed 8 logs of killing within 30 s (S. cerevisiae), 45 s (E. coli), and by 10 min (B. subtilis spores) of exposure.
Effect of starvation on survival of three bacterial isolates from an arctic soil
Authors: Nelson Louise M. , Parkinson D.
Published: April 2010

Three isolates, a Pseudomonas sp., a Bacillus sp. and an Arthrobacter sp., which had been isolated from a meadow soil at Devon Island, Canada, were subjected to starvation under varying conditions. The viabilities of the three isolates during starvation for 30 days in a carbon-free medium was assessed after the organisms had been grown continuously at varying rates in carbon- and nitrogen-limited media at 5 and 15 °C. Pseudomonas M216 was the most resistant to starvation stress. Bacillus M153 the least, and Arthrobacter M51 was intermediate in its response. Cells grown and starved at 5 °C survived longer than those at 15 °C. Carbon-limited Bacillus and Arthrobacter cells grown at high rates prior to starvation survived longer than those grown slowly, while in nitrogen-limited Arthrobacter the reverse was observed. The pattern of endogenous metabolism of the three isolates during starvation at 15 °C for 10 days was similar to that observed in other organisms. Levels of endogenous substrates such as carbohydrate and protein showed a rapid decrease in the initial 20 h of starvation, followed by a gradual decline over the remainder of the starvation period. The rates of endogenous metabolism of the isolates were positively correlated with their survival rates during starvation.
Increased in vitro sensitivity of Candida albicans to amphotericin B when grown in mixed culture with Escherichia coli
Authors: Mathieu L. G. , Dube D. , Lebrun M.
Published: April 2010

The growth of Candida albicans was inhibited by some Escherichia coli strains both in conventional batch cultures and also in a chemostat under conditions of constant addition of fresh medium. Concentrations of 0.2 μg amphotericin B per millilitre and of 2 μg nystatin per millilitre, which caused a slight inhibition of C. albicans in pure culture, exerted a strong fungicidal effect when the yeast was placed in mixed cultures with certain strains of E. coli. Candida albicans cells, inhibited by either E. coli or in mixed culture with polyene antibiotics, appeared larger and less uniformly stained by acridine orange than control cells from pure cultures. Addition of chloramphenicol to the mixed cultures, in quantities sufficient to kill the E. coli cells, abolished the increased sensitivity of C. albicans to amphotericin B or nystatin. In preliminary in vivo tests, E. coli did not sensitize C. albicans to the polyene antibiotics.
Incidence and relationship of group D streptococci with other indicator organisms in meats
Authors: Stiles M. E. , Ramji N. W. , Ng L.-K. , Paradis D. C.
Published: April 2010

Raw and processed meats were analyzed for presumptive group D streptococci using KF streptococcus agar. Counts were compared with coliform, presumptive Escherichia coli, and Enterobacteriaceae counts but no meaningful relationships were observed. Results indicated that group D streptococci and E. coli type I were principally contaminants from the packing plant, rather than at retail level. The predominating group D streptococcus in both beef and pork cuts was Streptococcus faecalis, while in processed meat (bologna), the predominating group D streptococci were Streptococcus faecium var. durons and Streptococcus faecium. Streptococcus bovis was not detected among the isolates from any meat samples. Marked differences were noted in numbers of group D streptococci in processed meat from different manufacturers. The results did not support the use of group D streptococci as alternative indicator organisms for meats. However, the association of group D streptococci with packing plant contamination may prove to be of value.
Apparent replication of an unusual virus-like particle in both a parasitoid wasp and its host
Authors: Stoltz Donald B. , Faulkner Gary
Published: April 2010

Nuclear inclusion bodies are found in the hemocytes of all tussock moth larvae parasitized by the braconid wasp Apanteles melanoscelus. These inclusion bodies represent the apparent site of replication of an unusual virus-like particle. Identical particles are observed in the nuclei of a small number of parasitoid calyx cells and are probably transmitted to host larvae during oviposition.
Characterization of the bacterial flora associated with root systems of Pinus contorta var. latifolia
Authors: Dangerfield J. A. , Westlake D. W. S. , Cook F. D.
Published: April 2010

Root systems of young and mature lodgepole pine (Pinus contorta Dougl. var. latifolia Englem.) were removed from forest stands and the associated aerobic bacterial flora isolated. Characterization of rhizoplane and control soil isolates from these tree root systems demonstrated differences from that reported for agricultural crops. Ammonifying, proteolytic, and amylolytic organisms were proportionately reduced within the rhizoplane. The rhizoplane organisms grew more slowly than the control soil isolates, although they responded in greater numbers to the addition of an amino acid supplement to the growth media. The rhizoplane organisms also showed an increased ability to solubilize phosphate. The chitinolytic organisms were suppressed within the rhizoplane of the mature tree but were stimulated by the young trees. With this exception, the rhizoplane microflora of older and younger trees were similar.
Alteration in ultrastructure and germination of Clostridium perfringens type A spores following extraction of spore coats
Authors: Labbe R. G. , Reich R. R. , Duncan C. L.
Published: April 2010

Ultrastructural changes in Clostridium perfringens type A strain FD-1 spores treated with alkali, mercaptoethanol–urea, or dithiothreitol (DTT) were observed by electron microscopy of thin sections. Two prominent coat layers were differentially removed or altered by extraction with 0.1 N NaOH at 4 °C or 50 mM DTT, pH8.5, at 37 °C. Alkali disrupted or completely solubilized an inner, narrow, electron-dense coat without appreciably altering the ultrastructural appearance of the outer, wide, less electron-dense coat. A decrease in electron density of the subcoat region occurred with either an alkali or DTT treatment of the spores. DTT treatment at pH 8.5 substantially removed the outer coat and partially disrupted the inner coat. Germination of alkali-treated spores was completely lysozyme-dependent. DTT-treated spores at pH 8.5 germinated without added lysozyme. The germination system of these DTT-treated spores became heat-sensitive, with lysozyme dependence occurring after heating at 75 °C for 20 min. DTT treatment at pH 10.5 resulted in lysozyme-dependent spores completely devoid of spore coats. Treatment with 10% mercaptoethanol in 7 M urea, pH2.8, resulted in a granular appearance of subcoat material and retarded the rate, but not the extent, of germination. These results indicate a close association of the normal germination lytic system with the subcoat region, possibly on the outer forespore membrane, and indicate a protective role of the spore coats in maintaining the heat resistance of the lytic system.
Oxidation of formate by mycobacteria of the Scrofulaceum group
Authors: Ishaque M. , Kim S. J. , Kato L.
Published: April 2010

Intact cells obtained from Mycobacterium scrofulaceum as well as from mycobacterial strains M.A6 and M.R56 isolated respectively from leprous tissues of armadillo and rat leproma and grown with glycerol as the oxidizable substrate catalyzed complete oxidation of formate. The stoichiometry of formate oxidase system yielded a value of 2 mol of CO2 produced per mole of O2 or per 2 moles of formate consumed. Cell-free preparations from these three strains of mycobacteria contained formate dehydrogenase which was associated exclusively in the particulate fraction. Formate oxidation was markedly stimulated by small amounts of selenite and molybdate added together. Formate-reduced minus oxidized difference spectra disclosed cytochromes of the b type while spectral evidence did not suggest the existence of cytochromes a or c components. The effect of 2-N-heptyl-4-hydroxyquinoline-N-oxide on the redox state of cytochromes indicated that formate oxidation was mediated by cytochrome b with absorption maximum of 556 nm and not of 562 nm.
A rapid fluorescent focus-inhibition test for determining dengue neutralizing antibody and for identifying prototype dengue viruses
Authors: Thacker W. Lanier , Lewis Vester J. , Baer George M. , Sather Gladys E.
Published: April 2010

Neutralizing antibody to dengue virus in human and animal sera was assayed by the rapid fluorescent focus-inhibition test (RFFIT). Neutralizing-antibody titers could be detected after only 24 h compared to 5–6 days required by the plaque-reduction test. The RFFIT is more definitive than the conventional complement fixation (CF) or hemagglutination-inhibition (HI) test in identifying prototype dengue viruses, is reproducible, and is applicable to the routine detection of neutralizing antibodies to dengue viruses.
Single–cell studies on the carrier state of bacteriophage IKe, a virus specific for conjugative plasmids of the N incompatibility and conjugative group
Authors: Iyer V. N. , James A. P.
Published: April 2010

Bacteriophage IKe is a virus that has been shown to have a degree of specificity for coliform bacteria carrying conjugative plasmids of the N group such as RM98. Infection of RM98+ cells by IKe results in the development of a viral-carrier state. The carrier state is accompanied by a slight reduction in the growth and division rate of individual cells in the populations of carriers on solid and in liquid media but in no lysis or extensive loss of viability. When secondary infection of the population was prevented by phage antiserum and single cells and their progeny examined, the carrier state was found to be propagated for at least four generations but eventually to be lost. The antiserum also has a selective inhibitory effect on carrier cells indicating that under these conditions, loss of the carrier state may occur by two separate mechanisms. The behaviour of the progeny of one cell suggested that in rare cases and in the absence of reinfection, the carrier state could be propagated for many more than four generations. The progeny of two other rare cells were found to be mutants. These are of special interest because their characteristics suggest that the regions on the genome of the plasmid that specify IKe-sensitivity and conjugative ability are physically and functionally separable regions.
Evaluation of an improved rapid coagglutination method for the serological grouping of beta-hemolytic streptococci
Authors: Lim Daniel V. , Smith Rosella D. , Day Susan
Published: April 2010

Grouping of beta-hemolytic streptococci was performed with the Phadebact® Streptococcus Test, a coagglutination method, and the results compared with serological grouping by the standard Lancefield precipitin method. Of 171 clinical specimens examined, 169 (98.8%) were grouped correctly by the Phadebact® Test after 24 h of continuous growth in Todd–Hewitt broth, In a parallel study, 96.9% of specimens that grew after only 4 h of incubation in broth were grouped correctly by the coagglutination method. In both studies, the accuracy of the coagglutination test was increased significantly by elimination of multiple-agglutination reactions through centrifugation of cultures and utilization of the supernatant fluid in the Phadebact® Test.
Nitrogen nutrition and regulation of cephalosporin production in Streptomyces clavuligerus
Authors: Aharonowitz Yair , Demain Arnold L.
Published: April 2010

When used as sole nitrogen source, certain amino acids (e.g., proline, asparagine) supported both growth and sporulation by Streptomyces clavuligerus streaked onto solid defined medium. Ammonium supported growth but suppressed sporulation. Amino nitrogen was best for cephalosporin production in liquid defined medium, although urea was almost as useful. A comparison of amino acids showed asparagine and glutamine to be the best nitrogen sources and arginine to be almost as good. Ammonium salts supported a somewhat lower growth rate than asparagine, but antibiotic production was very poor on these inorganic nitrogen sources. Addition of ammonium to asparagine did not affect growth rate but increased mycelial mass; cephalosporin production was reduced by about 75%. Antibiotic production was more closely associated with growth in the absence of ammonium than in its presence, indicating a strong inhibitory and (or) repressive effect of NH4+ on antibiotic production. Ammonium exerted its negative effect when added at 24 h or earlier, i.e. before antibiotic formation began.
Superiority of a soil debris isolation method over a beet seed colonization method for assay of Rhizoctonia solani at high soil inoculum densities
Authors: Roberts D. L. , Herr L. J.
Published: April 2010

A quantitative soil debris isolation method (all debris from known weight of soil plated) and a garden beet seed saprophytic colonization method were compared over a 1-year period for assaying Rhizoctonia solani populations. Four fields of different soil textures were selected. Within each field four areas of healthy and four areas of diseased (rhizoctonia root and crown rot) sugarbeets were sampled bimonthly from August 1976 until June 1977. The maximum numbers of R. solani colonies obtained by the debris method were 2 per gram of soil in areas of healthy beets, and 11 per gram of soil in areas of diseased sugarbeets. At such high inoculum densities the beet seed colonization method underestimated R. solani populations, because the inoculum per unit of soil exceeded the numbers of beet seeds per unit of soil available for colonization. Modifications of the beet seed method did not significantly alter results of colonization assays. Ranked correlation comparisons of assay methods yielded r = 0.81 for all data.
Transport of Neisseria meningitidis cultures: growth-supporting media and freezing as an alternative
Authors: White L. A. , Holbein B. E. , Spence M. R.
Published: April 2010

The abilities of Transgrow (TG), Thayer-Martin (TM), and New York City (NYC) solid media to maintain the viability of 12 strains of Neisseria meningitidis under various controlled conditions were assessed. The effects of charcoal impregnation of swabs, temperature, and an enriched CO2, atmosphere were examined with holding for up to 21 days. Recovery from samples held at 35 °C was, in almost all instances, greater than at 22 or 4 °C. A strong requirement for added CO2 was demonstrated, especially at lower temperatures. No positive effect could be attributed to the use of charcoal-impregnated swabs. NYC and TM media were the best overall, with the former permitting recovery from more than 75% of all samples held on slants for 20 days at 4 °C in an atmosphere of 5% CO2 in air. Freezing, with holding on dry ice, was a useful alternative to the use of growth-supporting media. This latter method eliminated the requirement for an enriched CO2 atmosphere.
Degradation of bacterial lipopolysaccharide by the slime mould Physarum polycephalum
Authors: Saddler John N. , Coote John G. , Wardlaw Alastair C.
Published: April 2010

A strain of the acellular slime mould Physarum polycephalum degraded lipopolysaccharides (LPS) from a variety of bacteria. The anticomplementary (AC) activity of LPS was greatly reduced, as was the content of lauric, myristic, and palmitic acids, and the ability to sensitize erythrocytes to agglutination by antibody. These results indicate that Physarum has enzymes which reduce the lipid A moiety of LPS. In contrast. 2-keto-3-deoxy-D-manno-actanoic acid (KDO), immunodominant sugars, and β-hydroxymyristic acid were scarcely affected. Both supernates and plasmodial extracts of Physarum had LPS-degradative activity and were able to attack both purified LPS and LPS in killed bacteria.
Low temperature induces decreased germinability of Cylindrocladium microsclerotia
Authors: Roth Don A. , Griffin Gary J. , Graham Philip J.
Published: April 2010

Numbers of germinable Cylindrocladium crotalariae microsclerotia (assayed at 26 °C) decreased progressively over 4 weeks when naturally infested soils were incubated at 6 °C. Lower numbers of germinable microsclerotia were obtained from a soil incubated at −3 than at 5 °C, while no germinable microsclerotia were found for soils incubated at −10 °C. Significantly, when soils incubated at −10 or at 6 °C for 4 weeks were transferred to 26 °C for 4 weeks, the low-temperature effect was partially reversed. Incubation of naturally infested soils under field conditions from October to February indicated that a similar low-temperature induced phenomenon exists in nature.Germinability of axenic laboratory-grown microsclerotia of C. crotalariae, C. floridanum, and C. scoparium incubated 4 weeks at 6 °C ranged from 0 to 91% (mean = 38%) of the initial germinability. Partial recovery of laboratory-grown microsclerotia from the low-temperature effect, by incubation at 26 °C, was demonstrated. Conductivity measurements of solutions bathing microsclerotia incubated at 6 °C were higher than those incubated at 26 °C for 4 weeks and indicated that chilling injury may account, in part, for decreased germinability of microsclerotia.
Properties of malate dehydrogenase isolated from Methanospirillum hungatii
Authors: Sprott G. D. , McKellar R. C. , Shaw K. M. , Giroux J. , Martin W. G.
Published: April 2010

A NADH-linked oxygen-tolerant malate dehydrogenase was purified 270-fold from cell extracts of Methanospirillum hungatii. Inhibitors of the enzyme included ADP, α-ketoglutarate, and excess NADH. Inhibition patterns for ADP were competitive with respect to NADH and non-competitive with respect to oxalacetate. Inhibition by α-ketoglutarate was non-competitive with oxalacetate as variable substrate and uncompetitive with respect to NADH. α-Ketoglutarate is surmised to function as an end-product inhibitor of the enzyme in reactions converting oxalacetate to α-ketoglutarate. No enzyme activity was detected in the direction of malate conversion to oxalacetate, in keeping with a strictly biosynthetic function of the enzyme. An analysis of variance of initial rate data fit to sequential and ping-pong equations showed that a sequential mechanism was preferred. The malate dehydrogenase of M. hungatii resembles those of many other bacteria and eucaryotic cells with respect to molecular weight (61 700) and reaction mechanism, but may be regulated differently.
Hydroxylase regulation in Candida tropicalis grown on alkanes
Authors: Gilewicz Michèle , Zacek Marcelle , Bertrand Jean-Claude , Azoulay Edgard
Published: April 2010

Candida tropicalis synthesizes a hydroxylase (3 to 5 nmol of product formed per minute per milligram of protein) and a cytochrome P-450 (0.10 to 0.13 nmol per milligram of protein) during growth on n-tetradecane. A three- to four-fold increase in the level of NADPH cytochrome c reductase is also observed in those cells as compared to the level of cells grown on glycerol. The most efficient inducers of the hydroxylase and of cytochrome P-450 are straight-chain alkanes having at least 10 carbon atoms. Alkenes and higher alcohols are also good inducers. There is little or no growth on ramified hydrocarbons such as pristane and on long-chain aldehydes and fatty acids.The partial inhibition of growth on decane is probably due to the denaturation of the microsomal electron carrier systems by the fatty acid formed by hydroxylation of the decane in the yeast.
Further studies of a new pathogenic mycobacterium (M. haemophilum sp. nov.)
Authors: Sompolinsky D. , Lagziel Annie , Rosenberg I.
Published: April 2010

Mycobacterium haemophilum is an acid-fast rod-shaped organism, originally isolated from deep subcutaneous granulomata of a patient with Hodgkin's disease. Like the other two mycobacterial skin-pathogens, M. ulcerans and M. marinum, M. haemophilum has a maximum temperature for growth below 37 °C. Mycobacterium haemophilum is distinguished from all other species examined by its requirement of haemin for growth and its complete lack of catalase activity. Extraneous catalase cannot replace haemin as a growth factor for this organism. Mycobacterium haemophilum can also be differentiated from other species by the patterns of electrophoresis of protein extracts and by gas–liquid chromatography of saponificated and methylated lipid extracts. A monospecific-agglutinating antiserum against M. haemophilum was obtained by adsorption of an immunoserum with M. intracellulare.A number of slow-growing mycobacterial species develop on monolayers of McCoy fibroblasts, and growth on these tissue cultures can be observed much earlier than on artificial media. Mycobacterium haemophilum is characterized by exclusively intracellular development.
Cyclic adenosine 3′,5′-monophosphate in Neisseria gonorrhoeae
Authors: Morriss Dorothy M. , Lawson John W.
Published: April 2010

Intracellular cyclic adenosine 3′,5′-monophosphate (cAMP) was measured in two laboratory strains of Neisseria gonorrhoeae. Decreasing the glucose content of a defined media from 33 mM to 5.5 mM glucose resulted in an 11- to 25-fold increase of intracellular cAMP.
Evidence for a periplasmic location in Comamonas terrigena of the inducible tyrosine sulfate sulfohydrolase
Authors: Maca H. William , Fitzgerald John W.
Published: April 2010

The location of the inducible and constitutive forms of tyrosine sulfate sulfohydrolase in Comamonas terrigena was investigated by subjecting resting cells to osmotic shock and to treatment with lysozyme in the presence of EDTA. The bulk of this enzyme present in induced cells was released by these procedures, suggesting that the induced form is cell wall associated. The constitutive form present in noninduced cells was not released under these conditions. Evidence was also presented which suggests that SO42− release by intact cells during exposure to tyrosine sulfate was primarily due to the action of the inducible form of the enzyme.
Live influenza vaccine: screening of attenuated virus strains by a 50% ciliary activity inhibition test in organ cultures of ferret trachea
Authors: Boudreault A.
Published: April 2010

This study of three live attenuated inhibitor-resistant influenza vaccines showed that these preparations are usually antigenic and that they caused no significant reactions when characterized by an index of attenuation equal to or slightly better than 1.0 arbitrarily attributed to the 'reference' attenuated A/Hong Kong/68 strain of Beare and Bynoe. This index, measured in vitro on ferret tracheal rings, is expressed as the ratio of the time required for ciliary activity inhibition of 50% of the rings by the tested candidate vaccine strain and the 'reference' attenuated strain. Induction of heterologous antibodies was also observed. Oral administration of underattenuated preparations did not cause the severe reactions which were observed when the same vaccine was administered intranasally.
Response of various cell lines to Escherichia coli toxic products
Authors: Konowalchuk J. , Speirs J. I.
Published: April 2010

Seven cell lines were compared with Y-1 and Vero cells for morphological response to E. coli toxic products. FL and WI-38, like Y-1 and Vero, responded to heat-labile enterotoxin. FL, HEp-2, HeLa, and BGM, like Vero but not Y-1, responded to heat-labile cytotoxin. FL was comparable to Vero in sensitivity to these two toxic products.
Release of rhodanese from Pseudomonas aeruginosa by cold shock and its localization within the cell
Authors: Ryan R. W. , Gourlie M. P. , Tilton R. C.
Published: April 2010

Whole cells of Pseudomonas aeruginosa possess rhodanese activity. The enzyme can be released by rapidly resuspending the cells in cold Tris–HCl buffer. Approximately 95% of the rhodanese activity is released by cold shock. Release of the enzyme can be inhibited either by preincubating the cells with Mg2+ or by incorporating Mg2+ into the shocking buffer. The effect of Mg2+ can be reversed by washing the cells twice with buffer prior to cold shock. While rhodanese can be released from P. aeruginosa by cold shock, lactic dehydrogenase, a cytoplasmic enzyme, remains within the cell. Diazo-7-amino-1,3-naphthalenedisulfonic acid, a compound which does not penetrate the cytoplasmic membrane, completely inactivated rhodanese and alkaline phosphatase, a periplasmic enzyme, whereas lactic dehydrogenase retained its full activity. These data suggest that rhodanese in P. aeruginosa, like alkaline phosphatase, is located distal to the cytoplasmic membrane in the periplasmic space. Electron micrographs also show that portions of the lipopolysaccharide outer membrane are shed from the cell during cold shock, while cells preincubated with Mg2+ did not release segments of their outer membrane.
The effects of temperature, incubation atmosphere, and medium composition on arthrospore formation in the fungus Trichophyton mentagrophytes
Authors: Emyanitoff Ruth G. , Hashimoto Tadayo
Published: April 2010

Several growth conditions were found to allow abundant arthrospore formation in T. mentagrophytes. These included growth at 32–37 °C on Sabouraud's medium (1% neopeptone, 4% glucose) and growth at temperatures below 32 °C solely on neopeptone or other complex peptide sources without the addition of glucose, a supplementary carbon source. Sabouraud's medium did not allow arthropsore formation at 30 °C under normal atmospheric conditions. However, if oxygen tension were reduced by partial replacement of air with either N2 orCO2 arthrosporulation did occur on Sabouraud's medium at 30 °C. The rate of germ tube elongation was lower under those conditions which supported arthrospore formation, suggesting a correlation between decreased rate of hyphal extension and arthrospore formation. Stimulation of arthrospore formation by sublethal concentrations of several antifungal agents tends to support this hypothesis.
Bacteriocins of phytopathogenic Corynebacterium species
Authors: Gross D. C. , Vidaver A. K.
Published: April 2010

The majority (85% of all strains tested) of 12 phytopathogenic Corynebacterium species produced bacteriocin(s) on nutrient broth – yeast extract (NBY) medium. All C. nebraskense, C. michiganense, C. insidiosum, C. oortii, and C. iranicum strains produced bacteriocin(s). The optimal conditions for production of 23 distinct bacteriocins by eight species of Corynebacterium generally were 20 °C and 4 days of incubation on NBY or on modified Burkholder's agar that lacked peptone (MBAL). Production in liquid was marginal and not augmented by adding mitomycin C. Bacteriocins generally had little effect on other strains within a species but were inhibitory to other species. Most bacteriocins appeared to be bactericidal proteins resistant to heat (75 to 80 °C, 30 min)but sensitive to proteolytic enzymes. Some strains of C. nebraskense, C. michiganense, C. insidiosum, and C. flaccumfaciens produced two bacteriocins which were clearly differentiated by varying or testing one or more of the following: conditions for production, the indicator, heat stability, and susceptibility to proteolysis. Within certain limitations, a convenient and reproducible typing scheme was devised for strain and species differentiation of most phytopathogenic corynebacteria.
The extraction and analysis of lipopolysaccharides from Pseudomonas aeruginosa strain PAO, and three rough mutants
Authors: Kropinski Andrew M. , Chan L. C. , Milazzo F. H.
Published: April 2010

Three spontaneously arising rough mutants of Pseudomonas aeruginosa have been isolated by selection for resistance to virulent lipopolysaccharide (LPS) specific bacteriophages. In addition, the first phages specific for rough mutants of P. aeruginosa were isolated. Using these phage and autoagglutination patterns in 4% NaCl and acriflavine, these mutants could be clearly distinguished from the wild-type strain and each other. Chemical analysis of the LPS together with chromatographic resolution of the polysaccharide moieties showed alterations in both O-specific side chains and core regions.
Modification transmissible induite in vitro chez Mycobacterium tuberculosis et Mycobacterium bovis
Authors: Lafont P. , Lafont J.
Published: April 2010

A biologically active material (fraction "S") is isolated from cultures of scotochromogenic mycobacteria, Mycobacterium tuberculosis, or Mycobacterium bovis by disrupting the cells, sedimentation through 2.2 M sucrose, and ultrafiltration. The fraction "S" induces the modification of tubercle bacilli into non acid-fast bacteria forming smooth colonies on nutritive glycerol agar within 24–36 h of incubation. Three new phenotypes are thus obtained; two proved to be stable upon subculturing.Frequently the phenomenon occurs with a very large part of the Koch's bacillus population exposed to the inducing agent effect. It can be reproduced with crude preparations of DNA obtained from the fraction "S." It is inhibited by concanavalin A. The observed modification does not correspond to a transfer of characteristics of the inducing agent from the donor mycobacteria; furthermore it can be manifested even in the strain used for the preparation of the fraction "S."
Transduction of penicillinase production in Staphylococcus epidermidis and nature of the genetic determinant
Authors: Olson Jr. W. C. , Parisi J. T. , Totten P. A. , Baldwin J. N.
Published: April 2010

Four strains of Staphylococcus epidermidis from clinical sources were capable of serving as donors for the transduction of either penicillinase production, ethidium bromide resistance, or tetracycline resistance. Three typing phages served as transducing phages and, depending upon the combination of transducing phage, donor strain, and recipient strain, the rates of transduction ranged between 10−5 and 10−9. In one strain, cotransduction of penicillinase production and ethidium bromide resistance was observed. Although ultraviolet irradiation kinetics indicated that both the tetracycline resistance and the penicillin resistance determinants were located on plasmids, only resistance to tetracycline could be eliminated by growth in the presence of curing agents or at elevated temperature. However, evidence was obtained by agarose gel electrophoretic studies that both the tetracycline resistance and the penicillin resistance determinants are located on separate plasmids in this organism.
Effect of thiols on macroconidia of Fusarium sulphureum
Authors: Barran Leslie R. , Schneider Edward F.
Published: April 2010

Treatment of Fusarium sulphureum macroconidial cells with five thiols alters their morphology. Macroconidial cells incubated in dithiothreitol (DTT), dithioerythritol (DTE), or thiourea differentiate into thick-walled, chlamydospore-like cells (thiol-induced spores). These cells appear similar in size and shape to chlamydospores in the light microscope, but differ markedly in cell wall structure when viewed in the electron microscope (EM). Incubation of macroconidia with both DTT and DTE also leads to the formation of large swollen cells (giant cells) which have a parietal cytoplasm and electron-transparent cell walls; most of these giant cells lyse within 3 to 7 days of incubation. Thiourea-induced spores are characterized by the deposition of a thick, electron-dense, extracellular layer and an accumulation of mitochondria. DTT and DTE, at the concentrations used, inhibit macroconidial germination while thiourea, mercaptoethanol, and cysteine do not. With the latter three thiols, the newly formed hyphal cells become elongated with either one or both ends swollen. Mercaptoethanol-treated cells contain an abundance of mitochondria. The DTT-induced spore differs from both macroconidia and chlamydospores with respect to cellular lipid and cell wall composition. While the thiols have different effects on the macroconidia, the fact that they all induce cell expansion suggests that they react at some common sites.
A dominant temperature-sensitive assembly mutant of adenovirus type 2
Authors: Carstens Eric B. , Magnan Johanne , Weber Joseph
Published: April 2010

An assembly negative temperature-sensitive mutant of Ad2, ts48 was shown to exert dominance over other ts mutants and wild-type virus during coinfection, by inhibiting virion assembly. Dominance was only expressed at the nonpermissive temperature.
Immunologic evidence that staphylococcal alpha toxin is oriented on membranes
Authors: Lo C. Y. , Fackrell H. B.
Published: April 2010

Antibodies to staphylococcal alpha toxin were separated into two distinct populations. One population prevented binding of alpha toxin onto erythrocyte membranes. The other population neutralized after the toxin was bound onto erythrocytes and thereby brought about an indirect hemagglutination reaction.The data suggest that alpha toxin has a membrane-binding region.
Isolation of Azospirillum from diverse geographic regions
Authors: Tyler M. E. , Milam J. R. , Smith R. L. , Schank S. C. , Zuberer D. A.
Published: April 2010

We have isolated Azospirillum (Spirillum lipoferum) from roots of grasses of several genera collected from a number of tropical and subtropical-temperate locations. Pure cultures were obtained from a small percentage of samples; no higher percentage was secured from tropical than from other grasses. Acetylene reduction and distinctive growth in N-free soft agar deeps were inadequate to identify this genus, although helpful in intial screening. Fluorescent antibody tests with antiserum against characterized strains were helpful. There is some evidence that this genus of bacteria may be favored in the rhizoplane.
Enzymatic hydrolysis of cellulosic materials by Sclerotium rolfsii culture filtrate for sugar production
Authors: Shewale J. G. , Sadana J. C.
Published: April 2010

The hydrolysis of purified celluloses (cotton, Avicel, Cellulose-123, Solka Floc SW40) and cellulosic wastes (rice straw, sugarcane bagasse, wood powders, paper factory effluents) by Sclerotium rolfsii CPC 142 culture filtrate was studied. Factors which effect saccharification such as pH, temperature, enzyme concentration, substrate concentration, produce inhibition, adsorption, and inactivation of enzyme and particle size were studied.Virtually no inhibition (<3%) of cellulose hydrolysis by the culture filtrate was observed by cellobiose and glucose up to 100 mg/mL. Filter paper degrading enzyme(s) (but neither carboxymethylcellulase nor β-glucosidase) was adsorbed on cellulose. The n value in the S. rolfsii system was calculated to be 0.32 for Avicel P.H. 101 and 0.53 for alkali-treated (AT) rice straw indicating penetration of cellulase into AT rice straw. In batch experiments at 10% substrate level, solutions containing 6 to 7%, 3.8 to 4.7%, 4.0 to 5.1%, and 4.2 to 4.9% reducing sugars were produced in 24 to 48 h from AT rice straw, AT bagasse, alkali – peracetic acid treated mesta wood and paper factory sedimented sludge effluent, respectively. The main constituent in the hydrolysate from cellulose was glucose with little or no cellobiose, probably due to the high cellobiase content in the culture filtrate.
Evaluation of the antiserum agar method for the serogroup identification of Neisseria meningitidis
Authors: Ashton F. E. , Ryan A. , Diena B. B. , Frasch C. E.
Published: April 2010

The antiserum agar method (ASA), which is based on the formation of immunoprecipitates around bacterial growth on agar containing meningococcal hyperimmune horse serum, was evaluated for serogroup identification of Neisseria meningitidis. Four hundred meningococcal strains were serogrouped by ASA employing horse antisera to serogroups A, B, C, Y, W135, Z, and 29E and compared to serogroup identification by bacterial slide agglutination (BA) employing rabbit antisera. Overall, there was 95% agreement between the two methods. The ASA proved to be more accurate than BA since 15 strains which cross-reacted with Y and W135 rabbit antisera by BA were specifically serogrouped as either Y or W135 by ASA. In addition, 5 out of 75 strains which were ungroupable by BA were serogrouped as either B or 29E by ASA. Repeat serogroup identification of 100 meningococcal strains by ASA provided identical results thus showing the reproducibility of the method. The ASA is advantageous to BA since it is more reliable, utilizes standardized antisera which do not have to be absorbed to remove cross-reactions, does not require the preparation of standardized bacterial antigen, and is simple to perform.
Chlortetracycline and sulfonamide resistance of fecal bacteria in swine receiving medicated feed
Authors: Welch B. , Forsberg C. W.
Published: April 2010

The fecal bacterial flora of swine receiving a ration supplemented with chlortetracycline, sulfamethazine, and penicillin was tested for resistance to chlortetracycline and sulfamethazine using anaerobic techniques and medium M-10. Approximately 15.5 and 1.4% of the flora grew in the presence of 25 and 100 μg of tetracycline/mL, respectively. Higher numbers of bacteria grew in the presence of similar concentrations of sulfamethazine.Thirty-five chlortetracycline-resistant isolates were tentatively identified by genera. Nine different genera were identified, four of these were Gram-positive and five were Gram-negative. The most common genera isolated were Streptococcus and Eubacterium.This demonstrates that in the fecal flora of swine fed rations supplemented with chlortetracycline, a wide variety of bacterial genera can be resistant to this antibiotic.
The fine structure of mature and germinating chlamydospores of Fusarium oxysporum
Authors: Stevenson I. L. , Becker S. A. W. E.
Published: April 2010

A number of features not described previously has been revealed in electron-microscope studies of mature chlamydospores of Fusarium oxysporum. On the maturation of one isolate, many spores formed a thick matrix-like layer containing electron-dense particles on the exterior surface of the spore wall. In thin sections of mature chlamydospores of the same isolate, cisternae of endoplasmic reticulum surrounding, and in close apposition to, the limiting boundary of the lipid bodies were revealed.The germination of chlamydospores was accompanied by (a) the rapid appearance of polysaccharide deposits and changes in the configuration of some subcellular organelles, (b) the formation of a new wall layer between the plasma membrane and the innermost layer of the spore Wall, (c) the rupture of the outermost coats of the spore wall, and (d) the emergence of the germ tube as an extension of the new wall layer.
Induction of β-galactosidase in Streptomyces violaceus
Authors: Sanchez Jesus , Hardisson Carlos
Published: April 2010

Synthesis of β-galactosidase by Streptomyces violaceus was induced by D-galactose and L-arabinose, and to a lesser extent by lactose, D-arabinose, and methyl-β-D-galactopyranoside. The synthesis of the enzyme was linear and started to increase 2–3 h after induction by galactose, reaching a maximum after 5–7 h. The highest level of specific activity was observed in 2% galactose, with an increase of 45 times over the basal level in glycerol. Isopropyl-β-D-thiogalactopyranoside (IPTG) and methyl-β-D-thiogalactopyranoside (TMG) inhibited induction by D-galactose, but did not influence enzymatic activity. Cellular extracts hydrolyzed o-nitrophenyl-β-D-galactopyranoside, but did not significantly hydrolyze lactose, melibiose, p-nitrophenyl-α-D-galactopyranoside, p-nitrophenyl-β-D-fucoside, or p-nitrophenyl-β-D-glucopyranoside. Rifampicin and chloramphenicol inhibited β-galactosidase synthesis in non-preinduced and in pre-induced cells. The inhibition by chloramphenicol was reversible.
Spiroplasmas: serological grouping of strains associated with plants and insects
Authors: Davis R. E. , Lee I.-M. , Basciano L. K.
Published: April 2010

Spiroplasma strains from plant and arthropod hosts, and from surfaces of flowers, were classified into three serological groups (designated I, II, and III) based on results from growth-inhibition tests. No significant cross reactions were observed among groups. The groupings were confirmed by ring-interface precipitin and microprecipitin tests, using membrane preparations as test antigens, and by organism-deformation tests. Serogroup I contained three subgroups: subgroup A (Spiroplasma citri strains Maroc R8A2 and C 189), subgroup B (strain AS 576 and closely related strains from honeybee or flowers), and subgroup C (corn stunt spiroplasma strains). Serogroup II contained strains 23-6 and 27-31 isolated from flowers of the tulip tree (Liriodendron tulipifera L.) growing in Maryland. Serogroup III contained strains SR 3 and SR 9 isolated from flowers of the tulip tree growing in Connecticut. The subgroups of serogroup I were based on organism deformation, microprecipitin, and ring-interface precipitin tests. The data are consistent with the hypothesis that the three serogroups represent no less than three distinct spiroplasma species.
Silver-resistant Enterobacteriaceae from hospital patients
Authors: Hendry A. T. , Stewart I. O.
Published: April 2010

The inclusion of agar medium containing 0.5 mM AgNO3 in the hospital laboratory replicaplating system for routine antibiotic-susceptibility determinations resulted in identification of species of Enterobacteriaceae (Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Protens mirabilis, and Citrobacter freundii) with silver resistance. Since the study began in October. 1975, 11 in-hospital patients receiving silver sulfadiazine for burn wound prophylaxis have yielded silver-resistant bacteria from their infected burns. During this treatment routine burn-site cultures from these patients yielded 230 isolates of Enterobacteriaceae, including 211 which were sulfonamide-resistant, 97 of which were also silver-resistant, and 38 of which were untested for silver resistance.Seven silver-resistant but sulfonamide-sensitive isolates were incidentally recovered from respiratory specimens from four nonburn patients with silver tracheostomy tubes, one silver-resistant sulfonamide-sensitive isolate was recovered from a small infected burn on the foot of an Emergency Room patient. Previous treatment of this burn was unknown.Representative AgNO3-resistant E. coli isolates from four patients were serologically untypable. Serotyping of representative isolates of K. pneumoniae showed a diversity of types except from two patients who had been in the same ward at the same time.
Mycophenolic acid production by Penicillium brevicompactum in two media
Authors: Doerfler D. L. , Bartman C. D. , Campbell I. M.
Published: April 2010

Penicillium brevicompactum produces mycophenolic acid as it grows vegetatively, not only on a simple medium where growth is slow but also on a richer medium where growth is less restricted. The implications of this finding on the association of fungal secondary metabolism with the idiophase in liquid and solid culture are discussed.
Microbiology of a northern river: bacterial distribution and relationship to suspended sediment and organic carbon
Authors: Geesey G. G. , Costerton J. W.
Published: April 2010

Epifluorescent microscopy showed as many as 4 × 106 bacteria/mL in the turbid waters of the Athabasca River near the tar sand deposits in northeastern Alberta. The numbers were usually similar upstream and downstream (60 km) from pilot-mining operations. The majority of bacteria existed as free-living cells in spite of the fact there were high concentrations of suspended sediment present (average 220 mg/L) during the ice-free period. Fluctuations in bacterial concentration were positively correlated (r = 0.86, P < 0.05) with total organic carbon concentrations in the river water.
The effect of pantothenate on sulfate metabolism and sulfur isotope fractionation by Saccharomyces cerevisiae
Authors: McCready R. G. L. , Din G. A. , Krouse H. R.
Published: April 2010

Growth of Saccharomyces cerevisiae in minimal salts – glucose – SO42− medium with varying concentrations of pantothenate (0–1000 μg/L) produced changes in the cellular lipid content and in the ratio of saturated to unsaturated fatty acids. Substantial differences in SO42−diffusion were also observed with changes in pantothenate concentration. During sulfate reduction, the δ34S value of the evolved sulfide varied with the pantothenate concentration ranging from −31‰ in the absence of pantothenate to 0‰ at 400−1000 μg/L pantothenate. The isotope selectivity is related to the effect of pantothenate concentration on cellular metabolism.