bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation of bacterial production in fresh waters by the simultaneous measurement of [35S]Sulphate and D-[3H]glucose uptake in the dark
Authors: Campbell P. G. C. , Baker J. H.
Published: April 2010

Sulphate uptake in the dark by phytoplankton constitutes a severe limitation to the determination of bacterial heterotrophic production from sulphate-uptake rates. Consequently a modification to the 35S-method has been developed involving size fractionation to separate the algae from the bacteria. Both the whole water sample and the algae-free filtrate are incubated in the dark with trace quantities of [3H]glucose, whereas the filtrate alone is incubated with 35SO4. The experimental determined ratio (whole sample glucose assimilation: filtrate glucose assimilation) is used to correct the measured sulphate uptake (filtrate) and yields an estimate of bacterial sulphate uptake in the whole sample.A potential filtration artefact has been demonstrated in the 35SO4 uptake methodology. Excision of the outer edge of the membrane filter and counting of the inner wetted circle alone eliminated this problem and significantly improved the analytical performance of the method: coefficient of variation ~ 5%, detection limit ~ 2 ng S ℓ−1 h−1. The modified [35SO4]–[3H]-glucose method was applied to samples from an English chalk stream: bacterial sulphate uptake was higher during the spring diatom maximum (10.6 ng S ℓ−1 h−1) than 3 weeks later when detritus dominated the seston (4.9 ng S ℓ−1 h−1). We estimate the corresponding rates of formation of particulate (bacterial) carbon to be 0.53 and 0.24 μg C ℓ−1 h−1 respectively.
Viruses in sewage: effect of phosphate removal with calcium hydroxide (lime)
Authors: Sattar Syed A. , Ramia Sami
Published: April 2010

During calcium hydroxide (lime) treatment (pH 9.5 to 10.5) of wastewaters for phosphate removal there was also a two-log removal of added poliovirus (type I, Sabin) from effluents. A similar virus reduction was seen in the sludge generated in these experiments. However, in view of the limitations of techniques for virus recovery from sludge, only a small portion of the infectious virus present in lime sludge may have been detected. Storage of lime sludge at 28 °C for up to 48 h produced no appreciable reduction in the virus titre.Five sets of field samples of sewage, effluents, and sludge from a sewage treatment plant (Kemptville, Ont.) which utilizes lime for phosphate removal were also examined for indigenous viruses using BS-C-1 cells. All of the samples of lime sludge and 80% of the samples of both sewage and lime-treated effluent revealed virus; after chlorination only 20% of the lime-treated effluent samples were positive for virus. In contrast, in an earlier study with essentially the same experimental set up, 76% of the sample of chlorinated primary effluent were found to contain virus. Because of the easily detectable quantities of infectious virus in lime sludge and due to the lack of virus inactivation during storage of such sludge, caution must be exercised in its handling and disposal.
Acetic acid and hydrogen metabolism during coculture of an acetic acid producing bacterium with methanogenic bacteria
Authors: Patel G. B. , Roth L. A.
Published: April 2010

Two microorganisms originally existing as a mixed culture obtained from an anaerobic digester fluid were separated for pure and coculture studies. One of these was motile, Gram-negative, and non-sporeforming, and it required yeast extract for growth and acetic acid production. This isolate produced H2 and did not need H2 and (or) CO2 for growth and acetate formation. The other isolate was a methanogen which resembled Methanobacterium arbophilicum in morphology and substrate specificity. Coculture growth of the two isolates in yeast extract broth (80% N2–20% CO2 gas phase) indicated that the non-methanogen produced up to four to five times more H2 than when grown separately. Although the growth of the non-methanogen was not enhanced by the removal of H2 by the methanogen, the hydrogen produced was essential for the growth of methanogen. Similar results were obtained when the non-methanogen was cocultured with Methanospirillum hungatii GP1. Cultivation of the non-methanogen in the presence of M. hungatii GP1 (under abundance of 80% H2–20% CO2) indicated that the acetate produced was consumed by M. hungatii, without inhibiting the growth of the other culture.
Influence of calcium on the differentiation and growth of aggregated organs in Sphaerostilbe repens
Authors: Botton B.
Published: April 2010

In the ascomycete Sphaerostilbe repens the vegetative mycelium aggregated into structures composed of aerial coremia and rhizomorphs immersed in the culture medium. The morphology and growth of the cultures were examined on a defined medium with and without calcium supplementation.Initiation and growth of aggregated organs occurred only if calcium was present continuously in the culture medium. On calcium-deficient media the fungus produced only vegetative mycelium which retained its ability to aggregate in the presence of the cation. Small concentrations of calcium (less than 1 ppm) stimulated aggregation of the mycelium, but higher concentrations (about 200 ppm) were necessary to obtain optimum development of the aggregated organs. Strontium partially replaced calcium, but lithium did not, as a stimulator of aggregation.
Isolation of Yersinia enterocolitica from surface and well waters in Ontario
Authors: Schiemann D. A.
Published: April 2010

Yersinia enterocolitica was isolated from forty-three surface- and well-water samples and one municipal supply. In many cases these samples were negative for coliform bacteria. After incubation of membrane filters on M-Endo agar LES at 35 °C for total coliform analysis, filters were held an additional 24 h at room temperature. This method was more productive for isolation of waterborne types of Y. enterocolitica than was cold enrichment in buffer alone or in combination with modified Rappaport broth. Most of the water isolates were atypical in being rhamnose-positive. Eighteen isolates (38%) were serotypable, presenting nine different serotypes with 0:4 occurring most frequently followed by 0:6,30. Water isolates of serotype 0:6,30 resemble human strains of the same serotype.
Early phases of degeneration of mycoplasma-like bodies in plant tissue cultures infected with aster yellows: morphological analogies with Mycoplasma hominis
Authors: Jacoli G. G.
Published: April 2010

Several forms of mycoplasma-like bodies (MLBs) were observed in electron micrographs of phloem cells from explants infected with aster yellows disease.The structures were found only in explants 11–25 days old, when the degenerating MLBs were first observed. They resembled those described by Anderson and Barile in 1965 for Mycoplasma hominis.A sequence of events in the degeneration of MLBs is postulated and morphological analogies with degenerating M. hominis are discussed.
The effects of a pesticide program on non-target epiphytic microbial populations of apple leaves
Authors: Andrews John H. , Kenerley Charles M.
Published: April 2010

The epiphytic microbial community was quantitatively and qualitatively altered when a standard pesticide schedule that comprised applications of an insecticide, a bactericide, and a fungicide was applied to McIntosh apple trees. Effects on non-target organisms were observed for two seasons by three indirect methods and three direct methods: plating of leaf washings, imprinting of leaves onto five different media, spore fall patterns, light microscopy, scanning electron microscopy, and isolation of propagules from leaves incubated in humidity chambers. Magnitude of reduction of bacteria, filamentous fungi, yeasts, and actinomycetes varied annually and between categories of microflora. Populations from treated leaves were reduced 10- to 1000-fold in 1976 and up to 50-fold in 1977. Qualitatively, fluorescent pseudomonads and lactic acid-type bacteria were among those depressed by pesticide. Fungal populations on treated leaves were less diverse than on control leaves. Aureobasidium was only slightly affected and incidence of Sporobolomyces was substantially higher on treated leaves than on controls. The results suggest that numbers of antagonists to foliar pathogens of apple which may occur as part of the natural epiphytic microbial community may be reduced by current pesticide programs and hence have possible implications for the development of biological approaches to integrated control strategies.
Evaluation of staphylococcal thermonuclease (TNase) assay as a means of screening foods for growth of staphylococci and possible enterotoxin production
Authors: Park C. E. , Derea H. B. El , Rayman M. K.
Published: April 2010

Samples of food, naturally and artificially contaminated with Staphylococcus aureus, were analyzed for enterotoxin and thermonuclease (TNase). With the exception of egg, all naturally contaminated foods with detectable amounts of staphylococcal enterotoxin were positive for TNase. The enzyme was also present in the majority of foods with over 1 million S. aureus cells per gram. In artificially contaminated foods, TNase was detected in all samples except egg, acidic foods in which growth of S. aureus was suppressed, and some samples of raw ground beef. Recovery of TNase was influenced by the type of food.
Comparison of three methods for identifying nonfermenting gram-negative rods
Authors: Hofherr Louise , Votava Henry , Blazevic Donna J.
Published: April 2010

Seventy-six strains of nonfermenting gram-negative rods were tested on the Analytab Products, Inc. (API) system and on conventional media. In addition, 51 strains were tested on the Oxi-Ferm system. When the identification results were compared, the API agreed with the conventional system on 41% of the isolates and Oxi-Ferm agreed with the conventional system on 72% of the isolates. API had the greatest difficulty in identifying Pseudomonas aeruginosa. API and Oxi-Ferm both had difficulty identifying P. cepacia. Oxi-Ferm had more individual discrepant biochemical reactions than did API when compared to the conventional media, but still maintained a higher percentage agreement with the conventional system.
Interaction of atrazine with soil microorganisms: population changes and accumulation
Authors: Percich James A. , Lockwood J. L.
Published: April 2010

A loam soil treated with atrazine at rates of 10, 30, and 100 μg/g soil resulted in increased populations of actinomycetes, bacteria, and fungi over those in non-treated soil. The increases were in proportion to the amount of atrazine and persisted for at least 2 months. Living actinomycete and fungal mycelia were incubated for 48 h in distilled water, nutrient broth, or soil containing 5 μg/ml (g) of the herbicide. Actinomycete and fungal mycelia accumulated atrazine from water to concentrations up to 87-fold and 132-fold, respectively, over that in the ambient medium. The maximum accumulation from soil by actinomycete mycelia was 26-fold and by fungal mycelia 13-fold. Fungi accumulated little or no atrazine from a nutrient medium whereas actinomycetes accumulated up to 13-fold. Dead mycelia usually did not accumulate atrazine in excess of the ambient concentration. Mycelium of Sclerotium rolfsii growing in a nutrient medium containing 20 μg atrazine/ml accumulated 157 μg/g wet weight after 8 days. Sclerotia subsequently produced after transfer of similar mats to soil contained 550 μg/g wet weight.
Simultaneous production of two types of Beta-lactamase in Escherichia coli and Providencia stuartii
Authors: Letarte Robert , Devaud-Felix Marlyse , Pechere Jean-Claude , Roy Brigitte
Published: April 2010

The production of β-lactamase has been studied in two strains isolated from clinical samples: Providencia stuartii MULB 501 and Escherichia coli MULB 130. These strains were selected for their high resistance level to penicillins and cephalosporins. Determination and identification of β-lactamase activity were achieved by combining several up-to-date methods including (i) neutralization by anti-β-lactamase sera, (ii) purification by affinity chromatography on cephalosporin C linked Sepharose 4B, (iii) determination of substrate specificity and kinetic values (Km and Vmax) by a computerized microacidimetric method, and (iv) isoelectric focusing.The results clearly demonstrate that in these two strains there is a simultaneous production of different β-lactamases: the first one is similar to the TEM penicillinase and the second one shares a typical cephalosporinase profile. This double β-lactamase production is a relatively rare phenomenon.
Production and properties of polygalacturonate lyase by an alkalophilic microorganism Bacillus sp. RK9
Authors: Kelly Catherine T. , Fogarty William M.
Published: April 2010

Bacillus sp. RK9 was isolated from soil and produced a constitutive polygalacturonate lyase. Production of the enzyme required the presence of complex nitrogen (peptone and yeast extract). Highest activity was obtained with an initial pH of 9.7. The organism was alkalophilic. No growth occurred below pH 7.5. The enzyme was purified by salt precipitation and diethylaminoethyl (DEAE) cellulose ion-exchange chromatography. The pH optimum for activity was 10.0 in 0.01 M glycine–NaOH buffer. Calcium alone, of divalent cations, activated the enzyme by 2.9-fold. Complete inhibition of enzyme activity wasachieved by 1 mM ethylenediaminetetraacetic acid (EDTA). Hydrolysis of substrate occurred in a random fashion and the enzyme was 50% more active towards acid soluble pectic acid (ASPA) than towards sodium polypectate.
DNA-dependent RNA and polyadenylic acid polymerase from phototrophically grown Rhodospirillum rubrum
Authors: Chow C. T.
Published: April 2010

DNA-dependent RNA and polyadenylic acid polymerases have been purified from phototrophic Rhodospirillum rubrum. Their properties have been found to be very similar to those of the previously reported heterotrophic R. rubrum enzymes. However, several important differences do exist between the enzymes from the phototrophic and the heterotrophic cells, such as the lack of response to added polyadenylic acid for poly A synthesis and the presence of the σ subunit in the phototrophic enzymes. Furthermore, additional purification steps were necessary for preparation of phototrophic enzyme fractions with high DNA-dependence.
Cellulase and β-glucosidase production by a basidiomycete species
Authors: Shewale J. G. , Sadana J. C.
Published: April 2010

The optimisation of cellulase and β-glucosidase production by a basidiomycete species was studied and cellulase and cellobiase production by this and Trichoderma viride (and its mutants) in shake flasks were compared. The former produced an active cellulase comparable to that of T. viride when tested on filter paper, carboxymethylcellulose, and cotton; however, it produced 20 to 26 times larger amounts of cellobiase.Both cellulase and β-glucosidase were obtained in good yield only when cellulose was the carbon source. The production of these enzymes was not repressed by readily assimilated carbon sources in the presence of cellulose. Only traces of cellulase and β-glucosidase were formed on glucose, fructose, maltose, and cellobiose although good growth was obtained on these substrates. These enzymes were not induced on sophorose, lactose, mannitol, or glycerol and growth was poor on these substrates. Cellobiose octaacetate was a less effective inducer of cellulase and β-glucosidase than was cellulose.
The production of extracellular amino acids by rumen bacteria
Authors: Stevenson I. L.
Published: April 2010

One hundred and sixteen freshly isolated rumen bacteria and 10 laboratory strains were studied for the production and excretion of free amino acids during growth in a basal medium containing glucose, cellobiose, and soluble starch as the energy sources, (NH4)2SO4 as the prime nitrogen source, volatile fatty acids, hemin, vitamins, Na2CO3, and cysteine as the reducing agent. Amino acid analyses of 48-h culture fluids of the isolates indicated the presence of alanine, glutamic acid, valine, aspartic acid, glycine, serine, lysine, methionine, leucine, isoleucine, threonine, histidine, arginine, phenylalanine, and tyrosine. Most isolates excreted some free amino acids. Alanine, glutamic acid, valine, aspartic acid, and glycine were found in the greatest concentrations with some isolates accumulating between 50 and 295 μg/ml of one or more of these compounds. Concentrations of the remaining amino acids rarely exceeded 20 μg/ml of culture fluid. Growth studies demonstrated that the amino acids were excreted during active growth of the bacteria and ceased shortly after growth became limited.
α,α- Trehalase of Trichoderma reesei
Authors: Vijayakumar P. , Ross W. , Reese E. T.
Published: April 2010

A simple adsorption and elution of the trehalase of Trichoderma reesei on bentonite increased the specific activity 70–80 times, with a recovery of 90%. This α,α-trehalase has an optimum pH of 4.4, a pl of 5.7, a Km of 3.1 × 10−3 M, and a specific activity of 50 μmol/mg. min−1.
Enzyme-linked immunosorbent assays for the detection of Neisseria gonorrhoeae specific antibodies
Authors: Brodeur Bernard R. , Ashton Fraser E. , Diena Benito B.
Published: April 2010

An indirect enzyme-linked immunosorbent assay (ELISA) using rigid polystyrene microliter plates was adapted to detect specific gonococcal antibodies against outer membrane-complex antigens extracted from Neisseria gonorrhoeae. The concentration of antigen to obtain maximum coating of the well was 10 μg protein per millilitre. The optimal binding of the primary antibody and enzyme-conjugated antiimmunoglobulin was achieved after 1 h at 37 °C. Under these conditions using gonococcal antisera, no cross-reactivity was observed with outer membrane antigens extracted from Neisseria meningitidis serogroups B, C, X, Y, and W135. Neisseria meningitidis serogroup A demonstrated low levels of cross-reactivity. All the non-pathogenic Neisseria spp. tested were negative (absorbance value at 400 nm/30 min < 0.15). The reaction of immune serum against outer membrane complex adsorbed to the microwells was completely inhibited with soluble-specific antigen but not with purified N. gonorrhoeae lipopolysaccharide. Quantitative inhibition permitted the measurement of low levels of antigen (0.5 μg/ml). The detection of N. gonorrhoeae antibody with ELISA is specific and highly sensitive.
Effet des acides gras sur l'activité antibactérienne du butylhydroxytoluène (BHT)
Authors: Saheb Samir A. , Turcotte Pierre , Picard Benoît
Published: April 2010

This study deals with the effect of the association of certain fatty acids with butylhydroxytoluene (BHT) on the antibacterial activity of this antioxidant. Evidence is drawn from the results as to an increase of the inhibitory effect of the antioxidant towards a few bacterial strains when it is associated with either lauric acid or palmitoleic acid.
Purification of Channel Catfish virus, a fish herpesvirus
Authors: Robin Jean , Rodrigue Alice
Published: April 2010

Channel Catfish virus was highly purified from host cells by precipitation with PEG-6000 and isopycnic centrifugation in a metrizamide gradient. As calculated from reconstruction experiments, only 0.09 and 0.05% respectively of the host DNA and the host proteins were recovered at the position of the viral band. The final recovery of infectivity was about 30%. Electron microscopy showed mostly intact viral particles.
Physical mapping of the genes controlling adenovirus paracrystal formation
Authors: Weber Joseph
Published: April 2010

The genetic properties and physical mapping of the genes controlling adenovirus-induced paracrystals were examined by means of a new, simplified technique. The induction of paracrystals was virus-strain dependent and blocked by several temperature-sensitive mutations. Using interserotypic recombinants between a paracrystal-producing and a non-producing strain of adenovirus, the principal paracrystal determining factor was mapped between coordinates 30 and 44 on the 100-unit adenovirus genome.
Effect of oxygen and nitrate on nitrogen fixation and denitrification by Azospirillum brasilense grown in continuous culture
Authors: Nelson L. M. , Knowles R.
Published: April 2010

Azospirillum brasilense was grown continuously at various levels of dissolved oxygen (O2) in a nitrogen-free medium containing malate as the carbon source. Steady-state cultures were established only at O2 concentrations less than 0.0150 atm (1 atm = 101.325 Pa) and rates of acetylene reduction (N2 fixation) and efficiencies of N2 fixation were maximal between 0.0050–0.0075 atm dissolved O2. These cultures appeared to be O2- or N2-limited. There was no evidence of a respiratory protective mechanism in this organism. Anaerobic denitrifying steady-state cultures were established with nitrate (NO3−) as the sole nitrogen source with no detectable N2 fixation. N2 fixation, but no denitrification, was observed when NO3− was decreased to 10 μg N per millilitre at 0.003 atm dissolved O2. In samples removed from the culture vessel, either activity could be induced with a lag of approximately 120 min by incubation under appropriate conditions.
Banded filaments associated with the aster yellows MLO in Vinca rosea L.
Authors: Carling D. E. , Millikan D. F.
Published: April 2010

The ultrastructure of an aster yellows mycoplasma-like organism was studied in the phloem of periwinkle (Vinca rosea L.) plants. Banded filaments were observed in association with mycoplasma-like organisms of characteristic morphology. The filaments were variable in length, from 50–100 nm in width, and displayed a regular periodic banding of alternating electron-dense and electron-lucent structures.
Physicochemical properties of Nebraska calf diarrhea virus hemagglutinin
Authors: Bishai F. R. , Blaskovic P. , Goodwin D.
Published: April 2010

Highly purified Nebraska calf diarrhea virus (NCDV)was prepared by cesium chloride density gradient centrifugation. The effect of temperature, pH, different concentrations of formaldehyde, chloroform, ether, ethyl alcohol, and methyl alcohol on NCDV hemagglutinin and virus morphology was studied. NCDV hemagglutinin was inactivated by temperature, pH 2.0, chloroform, ethyl alcohol, and methyl alcohol.
The effect of chemical fixatives on cell walls of Bacillus subtilis
Authors: Beveridge T. J. , Williams F. M. R. , Koval J. J.
Published: April 2010

Cell walls of Bacillus subtilis were treated with several chemical fixatives which are commonly used preparatory to electron microscopy; i.e., osmium tetroxide, formaldehyde, acrolein, crotonaldehyde, and glutaraldehyde. Dimensional analysis was performed on thin sections of fixed walls from plastic embeddings and, by means of the statistical technique of multiple comparisons, significant differences were found between wall thicknesses from the various fixations. These differences varied with the fixation time and the type of fixative used in the reaction. When compared to embedded walls which had been stained before fixation, the overall effect was a reduction in wall thickness which was attributed to fixative action and not to the embedding or staining processes. The reduction of wall thickness was even more apparent when dimensions of fixed walls were compared to published dimensions of both frozen sections and freeze-etch profiles.Since these fixatives bind to reactive sites within the wall fabric, a change in electrochemical charge density is effected which can be monitored in terms of heavy-metal-binding capacity. Most monoaldehyde fixatives and osmium tetroxide render the wall as reactive, or less reactive, to uranyl acetate as unfixed walls, whereas glutaraldehyde can significantly increase the binding capacity.
Effect of temperature, growth rate, and nutrient limitation on the yield and composition of three bacterial isolates from an arctic soil grown in continuous culture
Authors: Nelson Louise M.
Published: April 2010

Three bacterial isolates from an arctic meadow soil, Pseudomonas M216, Bacillus M153, and Arthrobacter M51, were grown continuously in carbon-and nitrogen-limiting media at 15 and 5 °C at three dilution rates from 0.04 to 0.01 h−1. Measurements of yield, viability, endogenous oxygen-uptake rate, and cell composition indicated that in general, these isolates were well adapted for growth at low rates and low temperature under nutrient limitation. Changes in cell composition with temperature, growth rate, and nutrient limitation followed patterns similar to those observed in organisms studied in other laboratories. Yields were higher at 15 than at 5 °C in Pseudomonas M216 and Arthrobacter M51 and the endogenous respiration rate tended to decrease with decreasing dilution rate. Substrate affinity (Ks) and μmax varied with temperature, and Pseudomonas M216 exhibited the lowest Ks for carbon and nitrogen and highest μmax under the growth conditions studied, except at 15 °C under carbon limitation where Arthrobacter M51 exhibited the lowest Ks. Only Bacillus M153 exhibited a significant loss in viability at low dilution rates and a detectable specific maintenance rate (0.0077 h−1), factors which may contribute to the low isolation frequency of the genus at the meadow site.
Effect of freezing and thawing on survival of three bacterial isolates from an arctic soil
Authors: Nelson Louise M. , Parkinson D.
Published: April 2010

Three isolates, a Pseudomonas sp., Bacillus sp., and Arthrobacter sp., which had been isolated from a meadow soil at Devon Island, Canada, were subjected to freezing and thawing at low rates under various conditions. When cells were frozen in sand or soil, survival was dependent on moisture level, storage time, and thaw rate. Pseudomonas M216 was most susceptible to freeze–thaw damage under these conditions. Arthrobacter M51 was the most resistant of the three isolates when frozen in sand or soil and when frozen at a high rate after growth at varing rates at 5 and 15 °C in carbon- or nitrogen-limited media. Pseudomonas M216 was more sensitive to freeze-thaw damage when NaCl was present in the freezing menstruum, even at low freezing rates. Survival of cells frozen in growth medium, water, saline, and soil extract was not affected by the freezing rate when it was less than 1 °C min−1. Soil extract did not protect cells from freeze–thaw damage any more than water and for Arthrobacter M51 survival was decreased when it was frozen in soil extract.
Cyclic nucleotides, cyclic nucleotide phosphodiesterase, and development in Myxococcus xanthus
Authors: McCurdy H. D. , Ho J. , Dobson W. J.
Published: April 2010

Exogenous cyclic nucleotide phosphodiesterase (PD) accelerated fruiting body (FB) formation and increased territory size of aggregates in Myxococcus xanthus. Both guanosine 3′5′- monophosphate (cGMP) and guanosine 5′-monophosphate (GMP) were antagonistic to the PD effect. Adenosine 3′5′-monophosphate (cAMP) increases FB numbers twofold in the absence but not in the presence of PD. PD induction is not affected by methionine or isoleucine, which inhibit, or by threonine, which stimulates, FB formation. There is an increase and subsequent decrease in cAMP levels during early glycerol-induced microcyst development but 10 mM theophylline or caffeine not only inhibited microcyst development but induced germination in the presence of glycerol.On the basis of these results and the reports of other investigators a tentative model is proposed based on a dual role for cyclic nucleotides in the development in M. xanthus.
Spore germination, colony development, and secondary metabolism in Penicillium brevicompactum: a radiogas chromatographic and morphological study
Authors: Doerfler D. L. , Nulton C. P. , Bartman C. D. , Gottlieb F. J. , Campbell I. M.
Published: April 2010

A study of the first 76 h of development of spores of Penicillium brevicompactum in batch-mode shake culture indicates that mycophenolic acid biosynthesis begins when the hyphae of germinating spores aggregate to form pellets. Supplies of mycophenolic acid so produced augment a pre-existing pool of the material that is associated with the dormant spore. Although acetate metabolism is active at all stages of development, incorporation of [1-14C]acetate into 2,4-dihydroxy-6-(1′,2′-dioxopropyl)benzoic acid, another secondary metabolite of the fungus, could not be demonstrated. The significance of these data are considered in terms of the function of mycophenolic acid and the substituted benzoic acid in the producing organism.
Rhizobium strain identification in Arachis hypogaea nodules by enzyme-linked immunosorbent assay (ELISA)
Authors: Kishinevsky B. , Bar-Joseph M.
Published: April 2010

The technique of enzyme-linked immunosorbent assay (ELISA) was used for serological identification of peanut Rhizobium strains both in cell suspension of pure culture and in single root nodules of groundnut (Arachis hypogaea) plants. Antisera of three peanut Rhizobium strains were tested against eight different Rhizobium isolates. Three serogroups identified by agglutination and immunodiffusion tests were confirmed by ELISA.In this experiment ELISA was more sensitive by four to six orders of magnitude than the agglutination and immunodiffusion tests and enabled the detection of Rhizobium antigens in cell suspensions of 104–105 cells per millilitre.The reactions of culture and nodule antigens were identical for all strains investigated.ELISA enabled the precise typing of rhizobial isolates in single small root nodules. The minimum fresh weight of nodule tissue necessary to perform the ELISA test was 0.4 mg crushed in 1 ml of phosphate-buffered saline (PBS).ELISA was also successfully used for strain identification in mixed inoculated plants. One of the strains in each pair formed most of the nodules examined.
California encephalitis virus activity in mosquitoes and horses in southern Ontario, 1975
Authors: Artsob H. , Wright R. , Shipp L. , Spence L. , Th'ng C.
Published: April 2010

A study was undertaken in 1975 to determine California encephalitis virus activity in southern Ontario. Three thousand and sixty-one mosquitoes, primarily Aedes species, were divided into 104 pools and inoculated into suckling mice. Isolates of snowshoe hare virus were obtained from one pool each of Aedes fitchii and A. triseriatus mosquitoes collected in the Guelph area. Serological testing of horse sera revealed extensive virus activity in southern Ontario and indicated that horses may serve as excellent monitors for California encephalitis virus.
Isolation and partial characterization of the parasporal body of Bacillus popillae
Authors: Weiner B. A.
Published: April 2010

The sporangial wall of Bacillus popilliae encloses a spore and parasporal body and is very resistant to breakage. High-energy sonication can disrupt this envelope and release free spores and parasporal bodies which retain refractility. Parasporal bodies, free spores, and sporangial debris were separated by centrifugation in linear sucrose gradients. Purified parasporal bodies are proteinaceous. Of the 17 amino acids detected, glutamic and aspartic acids are highest in concentration and account for the low isoelectric point of 4.5; a lipid moiety was not found. Parasporal bodies are soluble in 0.1 N NaOH, 8 M guanidine hydrochloride, 8 M urea, or alkaline thioglycollate. Paper electrophoresis at 3000 V separated soluble parasporal protein into three cathodic components. Solubilized or whole intact parasporal bodies fed to third-instar larvae of the Japanese beetle were not detectably toxic. However, solubilized parasporal protein was twice as toxic as the intact parasporal bodies when injected into the hemocoel.
Enterobacteriaceae in ground meats
Authors: Ng Lai-King , Stiles Michael E.
Published: April 2010

Presumptive Escherichia coli counts for 312 samples of non-frozen ground beef were determined and compared with proposed Canadian standards. Results for frozen pork sausages, packaged at manufacturer level, indicated little difference in distribution of presumptive E. coli loads compared with retail ground beef. Use of solid media and direct inoculation of EC broth at 45 °C did not give alternative, rapid methods of estimating E. coli loads in ground beef. Counts on violet red bile agar (VRBA) within 18–24 h incubation at 35 °C gave reliable estimates of coliform bacteria (bile-precipitating colonies) and Enterobacteriaceae (total count), with only 1.3 and 10.7% false positives, respectively. Bile-precipitating isolates from VRBA were primarily E. coli, also Serratia liquefaciens, aerogenic Enterobacter agglomerans, Enterobacter cloacae, Citrobacter freundii, and Klebsiella pneumoniae. Non-bile-precipitating colonies were primarily aerogenic E. agglomerans and S. liquefaciens; however, in the most probable number technique E. agglomerans was screened out. In addition to E. coli, E. agglomerans and S. liquefaciens were the principal types of Enterobacteriaceae in these samples. Enterobacter agglomerans gave a variety of IMViC reactions, including the type I (++−−) reaction, whereas S. liquefaciens were predominantly IMViC type −−++. Incubating EC broth at 45.5 °C, as opposed to 44.5 °C, reduced the number of false positives.
Induction of transformation competence in Azotobacter vinelandii iron-limited cultures
Authors: Page William J. , Tigerstrom Margaret von
Published: April 2010

Azotobacter vinelandii strains UW (Nif+) or UW1 (Nif−) were induced to form competent cells by growing cultures in Burk medium without added iron. Competent cells were generated in either liquid or solid medium. The competent culture was highly colored by the characteristic fluorescent green pigment of A. vinelandii but all pigmented cultures were not competent. In liquid culture, competent cells required a fixed nitrogen source (ammonia, nitrate, or urea) that was also a nitrogenase repressor. Glucose, sucrose, glycerol, and mannitol (1% w/v) were excellent C-sources for competence induction while acetate (1% w/v) and (β-hydroxybutyrate (0.2% w/v) were ineffective. Cells induced in liquid culture remained competent for a 12-h period before the end of the exponential growth phase, then competence decreased rapidly upon the initiation of the stationary phase of growth.
Factors influencing the in vivo stability of L-serine deaminase activity in E. coli K12
Authors: Beeraj R. D. , Morris J. F. , Newman E. B.
Published: April 2010

L-Serine deaminase (L-SD) is unstable in intact cells of Escherichia coli K12. The extent of this instability is dependent on the nitrogen content of the medium in which the enzyme is synthesized, and on that in which it is tested. Enzyme activity in cells grown with an inorganic nitrogen source is unstable in the presence of inorganic nitrogen; enzyme activity in cells grown with an organic nitrogen source is unstable in the presence of the amino acids glycine and leucine.
Sporulation in single-spore isolates from amitrole-induced multispored asci of Saccharomyces cerevisiae
Authors: Ashraf M. , Miller J. J.
Published: April 2010

Amitrole treatment causes multispored ascus production by cells of a yeast strain whose asci normally contain two diploid spores. Single spores were isolated from asci containing two to eight spores and their ability to germinate was determined. Cells in colonies grown from single spores sporulated in the same manner as the parent strain indicating that amitrole had not induced meiotic division in the developing asci.
Mitogenic and protective activity associated with a lipopolysaccharide from Coxiella burnetii
Authors: Paquet Jr. Andrew , Rael Eppie D. , Klassen David , Martinez Irene , Baca Oswald G.
Published: April 2010

A purified lipopolysaccharide (LPS) isolated from the rickettsial agent of Q fever, Coxiella burnetii phase 1, possesses some of the in vivo and in vitro biological properties previously only associated with bacterial endotoxins. The Coxiella LPS is mitogenic for guinea pig leukocytes, induces non-specific resistance in mice to virulent Candida albicans, causes dermal Schwartzman reactions, and is positive by the limulus lysate assay.
Studies of the spore walls of Agaricus bisporus and Agaricus campestris
Authors: Mendoza C. Garcia , Leal J. A. , Novaes-Ledieu M.
Published: April 2010

The composition and ultrastructure of spore walls of Agaricus bisporus and Agaricus campestris were compared by chemical and enzymatic assays and electron microscopy. Polymers of N-acetylglucosamine (chitin) and glucosamine (chitosan) were the major carbohydrate wall components of both species. The chitin to chitosan ratio in the spore walls of A. bisporus was about 0.38, while in A. campestris it was about 2.8. These polymers were associated with proteins, lipids (readily extractable and bound), melanin, and a low content of β-glucan. The quantity of protein, total lipid, melanin, or β-glucan was similar in spore walls of both species. With the electron microscope, the spore walls appeared as two well-defined layers which may correspond to microfibrils of chitin and chitosan in which the electron-dense melanin was located in the external layer.
Identification d'une nucléotide pyrophosphatase exocellulaire dans le milieu de culture de Streptomyces mediterranei ME/R 17
Authors: Pellon Gérard , Michel Georges
Published: April 2010

An exocellular pyrophosphatase, active on the nucleotide precursors of peptidoglycans, has been found in the culture medium of Streptomyces mediterranei ME/R 17. This enzyme was separated from the DD-carboxypeptidase by batchwise adsorption on DEAE cellulose. The pyrophosphatase had no strict substrate requirements, it hydrolyzed various UDP-sugar substrates: UDP-GlcNAc. UDP-MurNAc and UDP-MurNAc peptides, giving rise to the corresponding sugar phosphate and to UMP. The enzyme preparation also contained a 5′-nucleotidase activity and UMP was further split to give uridine. This nucleotidase activity was inhibited by potassium tetraborate. Both cytoplasmic and particulate preparations from cells of S. mediterranei also contained a pyrophosphatase activity while only the particulate fractions showed the DD-carboxypeptidase activity.The pyrophosphatase excretion was tested during the growth cycle. The activity of the enzyme showed a constant increase throughout the exponential growth and a stronger increase in the late exponential phase. Such a result could be correlated with a consumption of the nutrients in the culture medium, in fact a relatively poor culture medium had a strong positive effect upon the production of the exocellular pyrophosphatase.
Synthesis and excretion of polygalacturonic acid trans-eliminase in Erwinia, Yersinia, and Klebsiella species
Authors: Chatterjee Arun K. , Buchanan Gordon E. , Behrens Mary K. , Starr Mortimer P.
Published: April 2010

Various enterobacteria exhibit several patterns of synthesis and excretion of polygalacturonic acid trans-eliminase (PATE), one of the enzymes involved in degradation of pectic substances. In a strain of Erwinia chrysanthemi, PATE is an extracellular enzyme and is almost totally excreted. In strains of Yersinia enterocolitica and Yersinia pseudotuberculosis, PATE is a periplasmic and cytoplasmic enzyme. In a strain of Erwinia carotovora, PATE activity is extracellular, periplasmic, and cytoplasmic. In an "oxytocum" strain of Klebsiella pneumoniae, PATE is entirely cytoplasmic; none is found in the periplasm and almost none in culture supernatants. Cells (but not supernatants, because PATE is not excreted) of K. pneumoniae show much higher levels of PATE activity when grown on polygalacturonate than when grown on other carbon sources. A clinical strain of Y. enterocolitica synthesizes high levels of PATE activity (almost all cell-bound) when grown in the presence of gluconate, glycerol, or polygalacturonate, and considerably less activity when grown on glucose. A clinical strain of Y. pseudotuberculosis synthesizes barely detectable quantities of cell-bound PATE regardless of the carbon source. The phytopathogenic Erwinia strains synthesize and excrete high levels of PATE activity when grown on polygalacturonate, galacturonate, gluconate, or glycerol. Growth on glucose represses PATE activity in the Erwinia strains; the extent of repression differs between the two strains. The different patterns of synthesis and excretion are discussed in the light of the possible catabolic and (or) cytolytic (plant tissue-macerating) functions and the related ecological significance of PATE in these enterobacteria.
Naphthalenone production in Aspergillus parvulus
Authors: Bartman C. D. , Campbell I. M.
Published: April 2010

The naphthalenones asparvenone and its 6-O-methyl ether are produced by Aspergillus parvulus during vegetative growth in batch-mode, shaken cultures in a glucose–glycine–salts medium. The secondary metabolites first appear around the time when hyphae of developing spores begin to make contact with each other, i.e. at a very early stage of culture development. Resuspension in new medium of mycelium that is producing the naphthalenones fails to inhibit production. When A. parvulus is grown in parallel on a glucose–glycine–salts medium and on a glucose–malt–peptone medium, the naphthalenones appear first in the richer medium despite the fact that biomass proliferation is relatively unrestricted in that medium. Radiolabelled [1-14C]-acetate is taken up quickly by the fungus (k = 0.09 min−1) and is incorporated effectively into the naphthalenones.
Induction of reaginic (IgE) gonococcal antibodies in the rat by a common antigen of Neisseria gonorrhoeae
Authors: Ashton F. E. , Vijay H. M. , Lavergne G. , Brodeur B. R. , Diena B. B.
Published: April 2010

An antigen (ZAB) common to Neisseria gonorrhoeae was prepared by stepwise elution of a crude gonococcal antigen (ZA) from columns of diethylaminoethyl cellulose employing 0.02 M phosphate buffers, pH 7.6, containing increasing concentrations of sodium chloride. Rats immunized with ZAB produced reaginic (IgE) antibody which cross-reacted with ZA prepared from eight gonococcal strains by the passive cutaneous anaphylaxis (PCA) test. Heatingof the sera at 56 °C for 4 h destroyed the PCA activity. The PCA activity of the anti-ZAB rat serum was removed after absorption with ZAB antigen or with rabbit anti-rat IgE but not after absorption with gonococcal lipopolysaccharide or with heat-killed or formalinized gonococci. Treatment of ZAB with trypsin or heating at 100 °C for 30 min destroyed or reduced the antigenic activity respectively. Further purification of ZAB by filtration through Sephadex G-100 gave a preparation (ZAB2) which contained the common antigen as shown by the cross-reactivity of anti-ZAB2 rat serum with seven strains of N. gonorrhoeae. Fraction ZAB2 contained material which had a molecular weight less than 13 700 and was associated with the presence of material absorbing at 260 nm. The results of this study indicate that a low molecular weight antigen, which appears to be protein in nature and associated with nucleic acid, is common to the gonococcus and is the main antigenic component inducing reaginic (IgE) antibody in the rat.
Crude oil utilization by fungi
Authors: Davies J. S. , Westlake D. W. S.
Published: April 2010

Sixty fungal isolates, 34 obtained by a static enrichment technique from soils of northern Canadian oil-producing areas and 26 from culture collections, were screened for their ability to grow on n-tetradecane, toluene, naphthalene, and seven crude oils of varying composition. Forty cultures, including 28 soil isolates, were capable of growth on one or more crude oils. The genera most frequently isolated from soils were those producing abundant small condida, e.g. Penicillium and Verticillium spp. Oil-degrading strains of Beauveria bassiana, Mortieriella sp., Phoma sp., Scolecobasidium obovatum, and Tolypocladium inflatum were also isolated. Qualitative and quantitative differences were noted among the capacities of different crude oils to sustain the growth of individual fungal isolates. Data are presented which show that ability to grow on a pure n-alkane is not a good indicator of ability to grow on crude oil. Degradation of Rainbow Lake crude oil by individual isolates was demonstrated by gravimetric and gas-chromatographic techniques. The problems involved in determining the response and the potential of fungi to degrade oil spilled in the environment are discussed.
Nitrogen-metabolizing enzymes of Diplodia maydis, a Zea mays L. stalk rot causing fungus
Authors: Bussard James B. , Larson Russell L.
Published: April 2010

The nitrogen source available to Diplodia maydis in vivo is reported to affect the severity of stalk rot in maize. Nitrate and (or) ammonium salts were tested for their effect on the type of nitrogen metabolism found in Diplodia maydis in vitro. The level of glutamate dehydrogenase remained essentially constant on either nitrogen salt but nitrate reductase was induced by growth on nitrate salts and was not extractable on ammonium salts. Properties of nitrate reductase reported here are similar to those reported for the higher plant and Neurospora crassa enzymes. The relationship of nitrogen metabolism in Diplodia maydis to Zea mays L. stalk rot is discussed.
Ultrastructure of midgut events in the pathogenesis of Bacillus sphaericus strain SSII-1 infections of Culex pipiens quinquefasciatus larvae
Authors: Davidson Elizabeth West
Published: April 2010

The fate of Bacillus sphaericus strain SSII-1 cells ingested by Culex pipiens quinquefasciatus (= C. pipiens fatigans, C. fatigans, C. quinquefasciatus of authors; Diptera: Culicidae) larvae and the cytological events preceding death of the host were observed using electron microscopy. Bacillus sphaericus cells were digested rapidly in the anterior and central midgut. The outer cell wall layer and cytoplasmic ground substance disappeared soon after ingestion. Cytolysosomes became prominent in midgut cells as these cells gradually separated from one another. All bacteria, including B. sphaericus, were confined within the peritrophic membrane until after death of the host. Digestion by the larval host is confirmed as a possible mechanism for release of B. sphaericus toxin from the bacterial cells.
Polymyxin resistance in Agrobacterium tumefaciens and its effect on crown gall tumor induction
Authors: Liao C. H. , Heberlein G. T.
Published: April 2010

Polymyxin-resistant (PBLr) mutants of Agrobacterium tumefaciens A6, B6, and B6M were isolated from polymyxin-sensitive (PBLs) parent strains in a defined medium containing 600 μg of polymyxin B sulfate per millilitre. The weight and number of tumors induced by PBLr mutants on a variety of host plants such as carrot, potato, and pinto bean were 45–75% less than those induced by PBLs wild types. The crude cell envelopes (CCE) prepared from both PBLs and PBLr bacteria were inhibitory for tumor initiation when they were applied before or during the inoculation of viable tumorigenic bacteria, but not when they were applied 30 min after the inoculation of infectious bacteria. The potency to inhibit the tumor initiation by the CCE prepared from PBLs cells was approximately 50% higher than that by the equal amount of the CCE prepared from PBLr cells. The concentration of CCE preparations required to reduce tumor induction 50% in carrot and pinto bean was determined to be 2.6 mg/mL and 4.0–6.2 mg/mL for the CCE derived from PBLs and PBLr cells, respectively. These data suggest that the envelope structure or composition of PBLs and PBLr cells is distinct, and that the acquisition of resistance to polymyxin by agrobacteria modifies envelope structure or components which are essential for tumor initiation.
Populations of the spinach wilt pathogen, Fusarium oxysporum f. sp. spinaciae, in the root tissues, rhizosphere, and soil in the field
Authors: Reyes Andres A.
Published: April 2010

Populations of Fusarium oxysporum f. sp. spinaciae in root tissues and rhizosphere soil of diseased spinach plants were higher than in the root tissues and rhizosphere soil of healthy plants. Populations in soil rhizosphere were higher than in nonrhizosphere soil. The fungus populations were very low in the root tissues of the nonsusceptible strawberry, broccoli, Chinese cabbage, and mustard grown in the infested field. The populations were low at the beginning of the season, increased, and remained high during the summer, then dropped in the fall. The fungus populations ranged from 1600 to 2600 propagules/g in the top 10 cm of soil, declined sharply between 11 and 20 cm, and were nondetectable between 41 and 60 cm.