bluuebunny/crossref_metadata_2025 huggingface dataset:
Fine structure of the cell envelope layers of Flexibacter polymorphus
Authors: Ridgway H. F. , Wagner R. M. , Dawsey W. T. , Lewin R. A.
Published: April 2010

Electron microscopy of the filamentous gliding marine bacterium Flexibacter polymorphus demonstrated that the cell envelope consists of an electron-dense intermediate layer located between two unit-type membranes: an outer membrane, presumably of lipopolysaccharide, and an inner cytoplasmic membrane. Separation of living filaments into single cells by lysozyme suggests that a peptidoglycan moiety, possibly corresponding to the intermediate layer, might be situated between the two membranes. Cell division proceeds by invagination of the cytoplasmic membrane and intermediate layer forming a transverse septum. Cells generally fail to separate after the division process, so that a common outer membrane encloses all of the cells in a single filament.There is a continuous layer of macromolecular cup-shaped elements ('goblets') attached to the outermost surface of the lipopolysaccharide membrane. Tangential thin sections, as well as negatively stained preparations of envelope fragments (produced by sonication of autolyzed cells), showed that the goblets are arranged in a close-packed hexagonal array. The presence of electron-dense structures located between the outer and inner membranes, and exhibiting the same periodicity as the goblets, suggests that some part of the goblets penetrates the outer membrane and extends across the periplasmic space to the dense intermediate layer or cytoplasmic membrane. Spontaneous autolysis in aging cultures is accompanied by the formation and release into the culture medium of large numbers of outer membrane vesicles coated with goblets. A tentative reconstruction of the envelope of F. polymorphus, based on the fine-structural data, is presented.
Three antimicrobial metabolites from Aspergillus caespitosus
Authors: Mizuba S. , Lee K. , Jiu J.
Published: April 2010

Aspergillus caespitosus NRRL 5769 growing in broth containing small amounts of sitosterol produced substance(s) with greater inhibitory activity against Candida albicans ATCC 10231 than in broth without sitosterol. Subsequent isolation, purification, and structural elucidation yielded 5,6-dihydro-5(S)-acetoxy-6(S)-(1,2-trans-epoxypropyl)-2H-pyran-2-one (asperline (1), compound I) and two new metabolites. These were 5,6-dihydro-5(S)-acetoxy-6(S)-(1,2-trans propenyl)-2H-pyran-2-one (compound II) and 5,6-dihydro-5(R)-acetoxy-6(S)-(1,2-trans-epoxypropyl)-H-pyran-2-one (compound III). These three metabolites showed anti-microbial activity against C. albicans and against specific bacteria, fungi, and a trichomonad.
Identification d'actinomycètes aérobies isolés d'eau douce
Authors: Chea E. Hour , Leclerc H.
Published: April 2010

This paper presents the methods used for the study and identification of 172 actinomycetes strains isolated from samples of surface water and of sediments (soft water). For this analysis, two main criteria were used: the morphological and the biochemical study of the cellular constituents. A key for identification is proposed. [Journal translation]
The survival of Escherichia coli from freeze–thaw damage: the relative importance of wall and membrane damage
Authors: Calcott P. H. , MacLeod R. A.
Published: April 2010

When Escherichia coli is frozen rapidly in saline and thawed slowly, survival is very low; however, the inclusion of 3% glycerol or 1% Tween 80 in the saline freezing menstruum results in near complete survival. The release of material from, and penetration of, substances into the cell indicate that both membrane and wall damage occur during freezing and thawing. Glycerol, under these conditions, is able to reduce severely both the damage to the wall and membrane, whereas Tween 80 prevents only membrane damage. This indicates that freezing and thawing in saline results in membrane damage which is lethal to the cell whereas wall damage which occurs is not detrimental to cell survival.
Cellular and free lipopolysaccharides of some species of Neisseria
Authors: Johnson K. G. , Perry M. B. , McDonald I. J. , Russell R. R. B.
Published: April 2010

Cultures of eight non-pathogenic species of Neisseria grown in simple defined media released lipopolysaccharide (free lipopolysaccharide) by a process distinct from cellular autolysis. Analyses of the pure cellular and free lipopolysaccharides obtained from six species of Neisseria revealed that they were remarkably similar and were devoid of detectable O-antigen side chains. Three distinct types of core-oligosaccharides were demonstrated. Type I core-oligosaccharide was a branched structure of α-D-glucopyranosyl units (7 mol) terminated by a reducing end group of 3-deoxy-D-manno-octulosonic acid. Type II core-oligosaccharide contained D-glucose, 2-deoxy-2-amino-D-glucose, L-rhamnose, L-glycero-D-manno-heptose, 3-deoxy-D-manno-octulosonic acid, phosphate, and ethanolamine in a molar ratio of 3:2:1:1:1:1:1. Type III core-oligosaccharide was composed of D-glucose, L-glycero-D-manno-heptose, 3-deoxy-D-manno-octulosonic acid, and phosphate in a molar ratio of 3:3:1:1. Lipopolysaccharides of N. caviae and N. sicca contained type I core-oligosaccharides exclusively, while those of N. flava and N. perflava contained only type II core-oligosaccharide. Cellular lipopolysaccharide from N. cinerea contained core-oligosaccharides of types I and II in a ratio of 27:73, while the analogous preparation from N. flavescens contained core-oligosaccharide types II and III in a ratio of 21:4. Free lipopolysaccharides from these two organisms contained only one type of core-oligosaccharide. Lipid A components of all the lipopolysaccharide preparations were very similar being composed of about 25% by weight of dodecanoic acid, 3-hydroxy-dodecanoic acid, and 3-hydroxy-tetradecanoic acid.
Differentiation of mutants of Cephalosporium acremoniun in complex medium: the formation of unicellular arthrospores and their germination
Authors: Queener S. W. , Ellis L. F.
Published: April 2010

Differentiation of swollen hyphal fragments to unicellular arthrospores accompanied the synthesis of cephalosporin C by a series of Cephalosporium acremonium mutants during propagation in a complex medium. The complex medium supported significantly higher synthesis than the defined medium used in previous studies of differentiation in C. acremonium. The mutants differed in their ability to form unicellular arthrospores and to synthesize cephalosporin C, but a one-to-one correspondence between the two properties was not observed. An inverse relation was observed between the growth rates of the mutants and their ability to synthesize cephalosporin C: each mutant produced more antibiotic but grew more slowly than its parent strain. Germination of the unicellular arthrospores occurred in complex medium but differed significantly from the germination of conidia in seed medium. The unicellular arthrospores were examined by electron microscopy and compared with swollen hyphal fragments and slender hyphal filaments. The unicellular arthrospores had a thicker cell wall, rougher cell surface, and had one or more small indentations in their surface. The internal structure of the unicellular arthrospore resembled those of the swollen hyphal fragment and slender hyphal filament. Filaments had lower concentrations of lipid-containing vacuoles which were prevalent in both the swollen hyphal fragments and the unicellular arthrospores.
The pathogenicity of rough strains of Pseudomonas aeruginosa for Galleria mellonella
Authors: Kropinski A. M. B. , Chadwick J. S.
Published: April 2010

Rough mutants of two strains of Pseudomonas aeruginosa have been isolated by selection for resistance to virulent lipopolysaccharide- specific phages. The rough mutants fell into two classes on the basis of colonial morphology and agglutination by acriflavine and NaCl. The pigment and exoenzyme-synthesizing properties of these derivatives were identical with those of the parental cultures. The rough strains were 8- to 62-fold less pathogenic for the larvae of the wax moth (Galleria mellonella) than the smooth wild-type cells.
Mushroom inhibitors of dopa oxidation
Authors: Madhosingh Clarence
Published: April 2010

Two low molecular weight (about 1000) peptide inhibitors of dopa oxidation, purified by Sephadex chromatography, have been demonstrated electrophoretically in a preparation from the field mushroom, Agaricus hortensis.
DNA relatedness among species of Enterobacter and Serratia
Authors: Steigerwalt Arnold G. , Fanning G. Richard , Fife-Asbury Mary Alyce , Brenner Don J.
Published: April 2010

Species of Enterobacter and Serratia were examined for deoxyribonucleic acid relatedness to Klebsielleae, to atypical erwiniae, and to other members of Enterobacteriaceae. Deoxyribonucleic acid hybridization and then hydroxyapatite chromatography was the technique used to assess relatedness. Strains of Enterobacter cloacae formed two separate hybridization groups that correlate with the presence or absence of yellow pigment. Pigmented E. cloacae were 75–100% related, but they were only 40–50% related to unpigmented strains. Conversely, unpigmented strains were 70% or more related but were only 40–50% related to the pigmented strains. Both pigmented and unpigmented E. cloacae were 40–45% related to Enterobacter aerogenes and klebsiellae, and 20–30% related to Serratia species and Enterobacter hafniae. Atypical erwiniae were highly related to E. cloacae.Serratia marcescens strains formed one closely related group. Serratia liquefaciens strains formed a single, more disperse, relatedness group, as did isolates of Serratia rubidaea. These species were related throughout a substantial portion of their genomes. A group of lysine-positive "Citrobacter-like" strains were 40–50% related to Serratia species.Only four E. hafniae strains were tested. Two of these were highly related, while the other two were only 50% related to the reference strain. Enterobacter hafniae was only 15–20% related to other Enterobacteriaceae.
Studies of the cellular and free lipopolysaccharides from Neisseria canis and N. subflava
Authors: Johnson K. G. , Perry M. B. , McDonald I. J.
Published: April 2010

Cellular and free lipopolysaccharides (LPS) obtained from Neisseria canis and N. subflava were essentially identical. Both cellular and free lipopolysaccharides contained O-polysaccharides of the following composition: L-rhamnose (46 mol), D-glucose (16 mol), L-glycero-D-manno-heptose (2 mol), ethanolamine (2 mol), 3-deoxy-D-manno-octulosonic acid (1 mol), and phosphate (1.5 mol). The core oligosaccharide, which was common to the cellular and free LPS of both organisms, contained L-rhamnose (4 mol), D-glucose (2 mol), L-glycero-D-manno-heptose (2 mol), 3-deoxy-D-manno-octulosonic acid (1 mol), ethanolamine (2 mol), and phosphate (1.5 mol).Accumulated results on LPS composition and structure indicated that Neisseria perflava, N. subflava, and N. flava could not be combined into a single species. On the basis of its nutritional requirements and LPS structure, N. canis could be considered a strain of N. subflava.
Biosynthesis of chloramphenicol in Streptomyces sp. 3022a. Identification of p-amino-L-phenylalanine as a product from the action of arylamine synthetase on chorismic acid
Authors: Jones A. , Vining L. C.
Published: April 2010

Products obtained from the action of arylamine synthetase on [G-14C]chorismic acid were fractionated by gel filtration and ion exchange column chromatography to yield a partially purified radioactive component with an arylamine function. From its ultraviolet absorption spectrum and thin-layer chromatographic behaviour the product was considered to be p-aminophenylalanine and the identification was confirmed by co-crystallization with an authentic specimen. Specific deamination of the product with L-amino-acid oxidase indicated that it was the L- epimer. These results strengthen previous evidence that arylamine synthetase is at a branch point in the shikimic acid pathway, specifically diverting intermediates to the synthesis of chloramphenicol.
Morphological modifications of cells of Clostridium pasteurianum caused by growth on sulfite
Authors: McCready R. G. L. , Costerton J. W. , Laishley E. J.
Published: April 2010

The morphology of Clostridium pasteurianum cells grown on 10−2 M SO32− showed significant alteration in cell shape and the absence of the electron translucent reserve polysaccharide (amylopectin) when compared to sulfate-grown cells. At the lower sulfite concentrations (10−3 and 10−4 M SO32−) the cells showed the cytoplasmic changes noted above but the cell shapes were not modified.
Alteration of growth, infectivity, and viability of Neisseria gonorrhoeae by gonadal steroids
Authors: Fitzgerald Thomas J. , Morse S. A.
Published: April 2010

This report concerns the interaction of gonadal steroids with Neisseria gonorrhoeae. Growth of gonococci in nutrient broth was inhibited by testosterone propionate at 20 and 40 μg/ml,and by testosterone and 19-nortestosterone at 40 μg/ml. Progesterone was more effective than the three androgens; concentrations as low as 1 μg/ml significantly inhibited growth. A specific relationship of the degree of growth inhibition to the quantity of organisms present was apparent. In addition, progesterone influenced gonococcal virulence. Inoculation of chick embryos with untreated organisms produced a 73% mortality, whereas inoculation of hormonally treated organisms produced a 34% mortality. Progesterone appeared to retard optimal cell functioning. Studies on the viability of gonococci in nutrient broth indicated a steroidal enhancement of survival. In control suspensions, viable organisms were detected for 15 days: in suspensions containing progesterone at 10 μg/ml. viable gonococci were detected for 25 days. Hormonally treated bacteria that had remained viable for 22 days retained virulence for chick embryos. The data are discussed in terms of possible modification of gonococcal pathogenesis.
Detection of enteropathogenic Escherichia coli strains in wastewater by fluorescent antibody
Authors: Abshire Robert L.
Published: April 2010

Fluorescent antibody (FA) techniques were used to evaluate fluorescein-labeled enteropathogenic Escherichia coli (EEC) OB globulins as a means of presumptively detecting these serogroups in wastewater. Four of the more prevalent and incriminated EEC serogroups were detected by FA and isolated from wastewater. A total of 317 sewage isolates biochemically defined as E. coli were tested by FA and agglutination tests. Only a small number of these isolates (9/317, 2.8%) were serologically grouped as being enteropathogenic related strains. The frequency of occurrence of EEC organisms in a wastewater, as determined by FA, is reported. The use of highly specific OB fluorescent antibodies to monitor wastewater for the presence of EEC is discussed.
The distribution of the isocitrate lyase serine pathway amongst one-carbon utilizing organisms
Authors: Bellion Edward , Spain J. C.
Published: April 2010

A study of several one-carbon-utilizing organisms was conducted to determine the distribution of the recently found isocitrate-lyase-positive serine pathway of C1 assimilation. The results showed that this pathway is restricted to soil-isolated, non-pigmented Pseudomonas, initially isolated in methylamine enrichments, and to certain species of Hyphomicrobium. It was not detected in any organisms possessing a pink pigment.
Zoospore chemotaxis in Australian isolates of Phytophthora species
Authors: Halsall D. M.
Published: April 2010

Zoospores of Australian isolates of Phytophthora drechsleri, P. cryptogea, P. cinnamomi, P. nicotianae var. parasitica, and P. citricola were examined for their chemotactic responses to asparagine, glutamine, aspartate, glutamate, and structurally related compounds. Structural requirements for attraction include the α-amino-acid group with a short carbon chain terminating in an amide group. The one American isolate tested gave a different result and possible reasons for this are discussed.The pH of the environment was important, a neutral-charged molecule was more attractive than a negatively charged molecule, hence glutamate and aspartate were more attractive at pH 3.0 than pH 5.0. Zoospores tended to move away from regions with a high hydrogen ion concentration.Compounds other than amino acids were slightly attractive including several sugars and ethanol. Synergistic interactions between amino acids, ethanol; and sucrose were observed and may account for the high levels of attraction of zoospores to root exudates and extracts.
An improved synthetic growth medium for Halobacterium cutirubrum
Authors: Grey V. L. , Fitt P. S.
Published: April 2010

A synthetic medium is described in which Halobacterium cutirubrum grows as well as in complex media.
Comparative ultrastructure of selected oral streptococci: thin-sectioning and freeze-etching studies
Authors: Holt Stanley C. , Leadbetter E. R.
Published: April 2010

The ultrastructure of Streptococcus mutans, serotypes a–e, S. sanguis, S. mitis, and S. salivarius HHT, were examined by the techniques of thin-sectioning and freeze-etching. The cell walls varied in width between 15 and 46 nm and were covered with an electron-dense fibrillar or fuzz layer. The cytoplasmic membrane was in close association with numerous mesosomes which were, in turn, either closely associated or in contact with the bacterial chromosome. In freeze-etch replicas, the outermost layer of the cell wall was fibrous, and the cytoplasmic membrane was covered with particles composed of several subunits. Both particle-clusters and particle-free areas occurred on the surfaces of the cytoplasmic membrane, as well as a crystalline array in the ground plasm of the cell.
Isolation of ioxynil degraders from soil-enrichment cultures
Authors: Hsu JeMin C. , Camper N. D.
Published: April 2010

A soil enrichment technique was used to isolate microorganisms which could degrade ioxynil (3,5-diiodo-4-hydroxybenzonitrile). Many isolates obtained were able to degrade ioxynil to various products. However, only a fungal isolate (Fusarium solani) and a Gram-negative bacterium (Klebsiella ozaenae) released 14CO2 from ring-labeled ioxynil. No appreciable degradation was detected in pure cultures without the addition of exogenous nutrients. Results indicated that the degradation of ioxynil to CO2 proceeded more slowly in pure culture. Ioxynil was degraded in pure culture at a faster rate by F. solani than by K. ozaenae. Analyses of radioactivity distribution in the cultures indicated that a sizable fraction of radioactivity was in the form of polar products. Several degradation products were detected in the ethyl acetate extracts by thin-layer chromatography and subsequent radioautography. Screening of pure cultures of ioxynil degraders revealed that most isolates degraded ioxynil to the same products which were extractable with ethyl acetate.
The development in beef cattle manure of Petriellidium boydii (Shear) Malloch, a potential pathogen for man and cattle
Authors: Bell R. G.
Published: April 2010

Petriellidium boydii (Allescheria boydii) dominated the mycoflora of manure samples from three beef cattle feedlots after incubation at room temperature for 4 months. The possible dangers associated with this pathogenic fungus, which causes mycotic abortion in livestock, pulmonary allescheriasis in man, and mycetomas in both man and animals, are discussed. This fungus could create a health hazard in feedlots where in situ manure decomposition is encouraged.
Two toxic indole alkaloids from Penicillium islandicum
Authors: Cole Richard J. , Kirksey Jerry W. , Cutler Horace G. , Wilson David M. , Morgan-Jones Gareth
Published: April 2010

Two new isomeric metabolites, toxins A and B, were isolated from culture extracts of Penicillium islandicum. Both toxins had a molecular formula of C16H15O2N2Cl, and physical and chemical analyses indicated that they were indole alkaloids. LD50 of toxin A was about 75–125 mg/kg in day-old cockerels. Insufficient toxin B was available to determine accurate LD50 values. Toxin A moderately inhibited growth of wheat coleoptiles but did not inhibit growth of week-old intact corn and bean plants. Toxin B showed no plant-growth inhibition.
Release of bacterial alkaline phosphatase in the rumen of cattle fed a feedlot bloat-provoking diet or a hay diet
Authors: Cheng K.-J. , Hironaka R. , Costerton J. W.
Published: April 2010

Alkaline phosphatase (APase) was present in the bovine rumen in both cell-free and cell-associated states and levels of the enzyme varied with dietary regime. Reaction product deposition showed that the enzyme was associated with the mixed bacterial population. No enzyme was observed to be associated with protozoa. Trace activity of APase was also detected in the saliva. The presence of large amounts of APase in cell-free rumen fluid of cattle fed fine concentrate feed is believed to be due, in part, to the breakage of bacterial cells that occurs in the rumen.
Iron as a replacement for mucin in the establishment of meningococcal infection in mice
Authors: Calver G. A. , Kenny C. P. , Lavergne G.
Published: April 2010

Experimental infection of mice with Neisseria meningitidis was established by the injection of the bacteria suspended in solutions of various iron compounds. The progressive and fatal infection caused by otherwise non-lethal doses of organisms was produced in these mice after prior injection with ferrous sulphate or concomitant injection with iron sorbitol citrate or iron dextran. Reduction in LD50 to levels at least comparable to those obtained in the mucin challenge system was achieved; in some serogroups of N. meningitidis the LD50 was decreased more than a million fold. The results suggest that iron, which is a component of hog gastric mucin, is a factor involved in the establishment of meningococcal infection in mice. Use of iron compounds as injection medium offers a more advantageous system than mucin, since controlled administration of chemically defined substances occurs.
Repression of the acid phosphatase of Saccharomyces bisporus in relation to the polyphosphate content of the cells
Authors: Weimberg Ralph
Published: April 2010

The relationship between the level of stored polyphosphate in growing cells of Saccharomyces bisporus and the repression or derepression of the synthesis of the enzyme acid phosphatase (EC 3.1.3.2) was investigated. Time-course studies showed that there is no correlation between the cellular concentrations of either polyphosphate or orthophosphate and the ability of the cells to form this enzyme. The only compound investigated that was capable of repressing acid phosphatase synthesis was orthophosphate in the growth medium (i.e., orthophosphate outside the cell).
A particulate chitin synthase from Aspergillus flavus Link: the properties, location, and levels of activity in mycelium and regenerating protoplast preparations
Authors: Moore P. M. , Peberdy J. F.
Published: April 2010

Chitin synthase (EC 2.4.1.16) has been characterized in Aspergillus flavus. A Km value of 2.5 mM was obtained for the substrate UDPGlcNAc. The enzyme had a requirement for GlcNAc, and Mg2+ and activity was increased in the presence of soluble chitodextrins F1 and F2. The optimum activity was obtained using Tris–HCl buffer, pH 7.5, with a secondary peak at pH 6.2 and an incubation temperature of 29.5 °C.Distribution patterns of chitin synthase in protoplasts and mycelial material were very similar. The highest specific activity was found in a 200 000 × g fraction.Enzyme levels in growing mycelium increased during the exponential growth phase after which they declined. Activity also increased during the early stages of regeneration of both conidial and mycelial protoplasts, despite an initial lack in net protein synthesis. Chitin synthase levels were also dependent upon the carbon source available during regeneration.
Colonial variation in Xanthomonas campestris NRRL B-1459 and characterization of the polysaccharide from a variant strain
Authors: Cadmus M. C. , Rogovin S. P. , Burton K. A. , Pittsley J. E. , Knutson C. A. , Jeanes Allene
Published: April 2010

Stock cultures of Xanthomonas campestris NRRL B-1459 require special attention to maintenance and propagation to assure consistent production in good yields of the extracellular polysaccharide xanthan. Under customary conditions of propagative maintenance on agar slants, variant colony types develop that are smaller in size than the normal type. The rate of regression of the normal to the variant forms was diminished when the D-glucose content of the stock medium was sufficient to avoid depletion during storage and when transfer to fresh medium was reduced to 14-day intervals. Under conditions for polysaccharide production, the normal large-colony type gives crude culture liquors after 48 h of 7000 centipoise (cp) viscosity; the predominant variant form gives only 4000 cp. On the basis of 2.1% initial D-glucose, biopolymer yields for the normal and variant strains were 62 and 43%, respectively. Polysaccharide produced by the variant (small-colony type) differs adversely in solution properties from that of the parent strain (large-colony type); it differs also in its lower content of pyruvic acid and O-acetyl substituents. The molar ratios of constituent sugars (D-glucose, D-mannose, and D-glucuronic acid), however, were identical in polysaccharides with the normal and variant strains. Exclusion of colonial variants from fermentations is prerequisite to production of xanthan optimum in properties and yield.
Cation exchange in cell walls of gram-positive bacteria
Authors: Marquis Robert E. , Mayzel Kathleen , Carstensen Edwin L.
Published: April 2010

The relative affinities of various cations for anionic sites in isolated, bacterial cell walls were assessed by means of a technique involving displacement of one cation by another. The affinity series determined was [Formula: see text]. High affinity was correlated with low mobility of the bound ions in an electric field. The net cation-exchange capacities of walls isolated from a variety of bacteria were estimated by preparing the magnesium forms of the walls, washing them well with deionized water to remove supernumerary ions, and then completely displacing the magnesium with Na+ or H+. Total amounts of magnesium displaced varied from 73 μmol per gram dry weight, for walls of the teichoic acid-deficient 52A5 strain of Staphylococcus aureus to about 520 μmol per gram for Bacillus megaterium KM walls. The amount of displacable magnesium was inversely related to the physical compactness of the walls, except for walls of Streptococcus mutans GS-5. It was found that magnesium or calcium ions can each neutralize, or pair with, two anionic groups in walls suspended in ion-deficient media. Previous work had indicated that these ions may pair with only one anionic group at high ionic strength. Therefore, it appeared that there is a great deal of flexibility in the arrangement of charged groups in the wall. It was concluded also that for cells growing in commonly used laboratory media, which generally contain large excesses of monovalent versus divalent cations, there is a mix of small, cationic counterions in the wall and that monovalent cations may predominate even though the wall has higher affinity for divalent ions.
In field survival of Rhizoctonia solani in soil and in diseased sugarbeets
Authors: Herr Leonard J.
Published: April 2010

Persistence of Rhizoctonia solani in the field was investigated by ascertaining survival (competitive saprophytic activity) in soil and survival in diseased plants. Except for one instance, low levels of R. solani survived overwinter in artificially and naturally infested soils. In a sandy loam soil, cropped to sugarbeets, inoculum density increased throughout the growing season from low early spring levels to high levels in July and August. In a silty clay soil, cropped to sugarbeets, inoculum density remained low with only a slight increase throughout the growing season. Survival of R. solani in diseased sugarbeets placed on the soil surface was greater than survival in diseased beets buried in soil. Little reduction in percentages of beets yielding R. solani colonies took place from November to April in either buried or unburied beets. The major reduction in survival of R. solani in buried beets occurred during the 6-week interval from April to June.
A modified procedure for studying enzyme secretion in yeast sphaeroplasts: subcellular distribution of invertase
Authors: Holbein Bruce E. , Forsberg Cecil W. , Kidby Denis K.
Published: April 2010

A significantly modified procedure for investigating enzyme secretion from yeast sphaeroplasts, and results from its application are described. Sphaeroplasts were derepressed for invertase biosynthesis in the presence of helicase and fractionated to reveal the distribution of high and low molecular weight forms of invertase. Secreted enzyme was found to be of high molecular weight, exclusively. Less than 10% of the total invertase activity was present in washed sphaeroplasts and of this, 43% was soluble, consisting of both high and low molecular weight forms of invertase. Washed membranes retained 32% of the internal invertase activity, and on solubilization with Triton X-100 the enzyme was found to be of an intermediate molecular weight. These results are consistent with the hypothesis that invertase is glycosylated at the plasma membrane.
Baculovirus-like particles in the reproductive tracts of female parasitoid wasps
Authors: Stoltz Donald B. , Vinson S. Bradleigh , MacKinnon Edmund A.
Published: April 2010

Virus-like particles have been found in specific regions of the reproductive tracts of three different braconid wasps, all parasitoids of the tobacco budworm, Heliothis virescens. The particles are nuclear in origin, and Feulgen cytochemistry of particulate fluid in the calyx and oviducts of one species has revealed the presence of DNA. On the basis of apparent structural homologies, it is suggested that the parasitoid particles are related to baculoviruses.
Bacteriocins of Streptococcus bovis
Authors: Iverson W. G. , Millis Nancy F.
Published: April 2010

Forty-seven strains of Streptococcus bovis were tested for bacteriocin production. Fourteen were found to produce bacteriocins, while all 47 were sensitive to at least one of these bacteriocins. The bacteriocins, on the basis of their host range on S. bovis strains, formed six groups. A representative of each group was selected and characterized by temperature stability, sensitivity to trypsin and lipase, sedimentation by centrifugation, ability to pass through dialysis tubing, host range on other bacterial species, and conditions for production in liquid media. A correlation between mannitol fermentation and bacteriocin production was noted.
The citric acid fermentation by Aspergillus niger: regulation by zinc of growth and acidogenesis
Authors: Wold William S. M. , Suzuki Isamu
Published: April 2010

The citric acid fermentation by Aspergillus niger is divided into two consecutive phases, a growth phase when the cells proliferate but do not accumulate citrate, followed by an accumulating phase when they produce citrate but do not proliferate, or else do so at a much reduced rate. When studied in a low sucrose (0.4–0.8%) minimal salts medium the growth-accumulation alternative was controlled by the concentration of zinc: high zinc (about 1–2 μM) maintained growth phase, while at low zinc (below 1 μM) growth became limited by zinc deficiency and the cultures passed into accumulating phase. Addition of zinc to accumulating cultures resulted in their reversion to growth phase. Iron, manganese, and calcium at concentrations as high as 5–10 μM had no influence on either growth or citrate accumulation. These results suggest that zinc plays a role in the regulation of growth and citric acid accumulation.
Competition between Phytophthora cinnamomi and Trichoderma spp. in autoclaved soil
Authors: Kelley W. D. , Rodriguez-Kabana R.
Published: April 2010

Results from analyses of β-glucosidase (EC 3.2.1.21) and phosphatase (EC3.1.3.1; EC 3.1.3.2) activities indicated that presence of a Trichoderma isolate reduced development of Phytophthora cinnamomi. It was also observed that P. cinnamomi was more competitive in coinoculated cultures than in cultures where Trichoderma was added on day 3. Analysis of trehalase (EC 3.2.1.28) activity indicated that Trichoderma either utilized portions of the P. cinnamomi mycelium as substrate or the action of P. cinnamomi released additional nutrients not normally available to Trichoderma. The stronger Trichoderma isolate was T. harzianum.
California encephalitis virus proliferation in Yukon mosquitoes incubated at low temperatures
Authors: McLean D. M. , Grass P. N. , Judd B. D. , Wong K. S. K.
Published: April 2010

Replication of a subarctic Bunyavirus, California encephalitis (snowshoe hare subtype), was detected in salivary glands and thoraces of wild-caught Aedes communis mosquitoes from the Yukon Territory, after intrathoracic inoculation with 0.1 to 100 mouse LD50 virus, and incubation for 7 to 21 days throughout their viable temperature range of 0 to 23 °C. Immunoperoxidase staining confirmed that viral replication occurred in the cytoplasm of acinar cells of salivary glands, both by light microscopy and electron microscopy. Replication of another subarctic Bunyavirus. Northway, and a subtropical Flavivirus, Murray Valley encephalitis, was also demonstrated by infectivity titrations and immunoperoxidase reactions in salivary glands of A. communis incubated at 0, 13, and 23 °C for 7 to 21 days.
A technique for the differential isolation of hop mosaic virus and hop latent virus
Authors: Probasco E. G. , Skotland C. B.
Published: April 2010

Two rod-shaped viruses of similar length occurring in hops were isolated from a mixed infection. One (hop mosaic virus) infected Nicotiana clevelandii, produced mosaic symptoms in mosaic-sensitive hop cultivars, and did not infect Chenopodium murale. The other (hop latent virus) infected C. murale but not N. clevelandii and did not produce mosaic symptoms in hops. Neither N. clevelandii nor C. murale developed distinct symptoms after infection with the respective virus. Both viruses produced a systemic chlorotic flecking in Cluster hop seedling clones.
Photoreactivating property of the Vibrio cholerae cell system
Authors: Chanda P. K. , Chatterjee S. N.
Published: April 2010

Ultraviolet-inactivated chlora phage PL163/10 underwent a maximum of about 36% of photoreactivation within the host V. cholerae cells. U V-inactivated but non-infected V. cholerae cells also underwent the same degree of photoreactivation.
The metabolism of carbohydrates by extremely halophilic bacteria: identification of galactonic acid as a product of galactose metabolism
Authors: Hochstein Lawrence I. , Dalton B. P. , Pollock Glenn
Published: April 2010

Cell-free extracts prepared from the extremely halophilic bacterium Halobacterium saccharovorum oxidize galactose and accumulate a product which reacts as if it were a lactone. The product does not act as a reducing sugar and contains all six of the carbon atoms initially present in galactose. The product was judged to be galactonic acid, based on the behavior of the acetylmethyl ester derivative of the product and the pentaacetyl derivative of the galactonic methyl ester during gas chromatography.
Biodegradation rates of components of petroleum
Authors: Walker J. D. , Colwell R. R. , Petrakis L.
Published: April 2010

Rates of microbial biodegradation of components of South Louisiana crude oil were determined by computer analysis of data obtained from computerized mass spectrometry. Total residue of the oil decreased exponentially with time, with maximum decrease noted at logarithmic phase, whereas asphaltenes and resins increased at the logarithmic phase of growth. Saturates decreased continuously during growth. Microbial degradation of components of crude oil was concluded to be a dynamic process.
Production of volatiles from decomposing plant tissues and effect of these volatiles on Rhizoctonia solani in culture
Authors: Lewis J. A.
Published: April 2010

Volatiles, of which NH3 is a major component, were evolved from decomposing immature corn tissue (C:N 9) and affected R. solani in culture two ways: they supplied additional nitrogen to the growth medium so that fungal mycelial growth increased; and they raised substrate pH from 5.5 to 8.2 which induced melanization of mycelium. Volatiles increased fungus growth and pigmentation within 2 weeks of amendment addition to soil. Increases were concomitant with NH3 production from corn tissue. More NH3 evolved from decomposing corn tissues of C: N 9 and 17 than from those of C:N 33 and 81. More growth and pigmentation occurred in flasks through which volatiles from decomposing corn (C: N 9) were passed than in flasks through which volatiles from nonamended soil or decomposing com (C: N 81) were passed. Carbon dioxide from decomposing tissues did not affect growth or pigmentation. Twice as much NH3 evolved from corn tissue (C: N 9) which decomposed in saturated soil than from tissue which decomposed in soil at 50% of its water-holding capacity. Pigment production doubled under saturated conditions.
Pathways of glucose catabolism in Mycobacterium smegmatis
Authors: Bai N. Jayanthi , Pai M. Ramachandra , Murthy P. Suryanarayana , Venkitasubramanian T. A.
Published: April 2010

Glucose metabolism in Mycobacterium smegmatis was investigated by the radiorespirometric method and by assaying for key enzymes of the major energy-yielding pathways. Glucose is oxidized in this organism mainly through the Embden–Meyerhof–Parnas pathway, irrespective of the carbon source used for growth. The pentose phosphate pathway plays only a minor role and its extent depends on the carbon source used for growth. Enzymes of glycolytic and oxidative pathways were detected in cells grown on glucose, glycerol, or pyruvate but enzymes of the Entner–Doudoroff pathway could be detected only in glucose-grown cells. Labeled acetate is utilized by cells cultured on glucose, glycerol, and pyruvate. In all cases more of C1 of acetate was converted to CO2 while incorporation into cellular constituents was maximum from C2 of acetate.
Inhibition of growth of N. gonorrhoeae by bacterial interference
Authors: Shtibel Rosa
Published: April 2010

Observations made in our laboratory during the past 3 years showed that the growth of some Neisseria gonorrhoeae cultures was inhibited in the presence of various bacterial contaminants of urogenital specimens. A total of 647 cultures confirmed as containing N. gonorrhoeae were examined in this study. The first part of the study was carried out on 520 N. gonorrhoeae cultures. Of these 520 cultures, 110 (21.1%) showed contamination on purity plates (GC medium, antibiotic-free). When further subcultured, 96 (87.3%) of the N. gonorrhoeae strains grew in pure culture, but 14 (12.7%) failed to grow. Subsequently, experiments were carried out on 127 pure N. gonorrhoeae cultures. The bacterial species that inhibited the growth of N. gonorrhoeae are listed in order of frequency: Neisseria meningitidis, Staphylococcus epidermidis, Corynehacterium species, Staphylococcus aureus, Streptococcus group A, and Neisseria subflava.
Lecithinase-negative variants of Clostridium perfringens; the identity of C. plagarum with C. perfringens
Authors: Nakamura S. , Sakurai M. , Nishida S. , Tatsuki T. , Yanagase Y. , Higashi Y. , Amano T.
Published: April 2010

Identity of Clostridium plagarum (Prévot) com. nov. (1938) with C. perfringens was demonstrated in the tests for the cultural and biochemical properties, DNA–DNA homology, susceptibility to C. perfringens-specific lysin, complementary synthesis of C. perfringens θ-toxin between C. plagarum and θ-toxin-negative mutants of C. perfringens, as well as the tests for gas-chromatographic patterns.
Un milieu gélosé pour le dénombrement direct de Staphylococcus aureus : milieu au plasma de porc pour S. aureus (PPSA)
Authors: Devoyod J-J. , Millet Liliane , Mocquot G.
Published: April 2010

A selective agar medium (pork plasma medium for S. aureus (PPSA)) enables the direct enumeration of coagulase-positive staphylococci. This medium is based on the Baird-Parker agar without egg yolk and is supplemented with pig plasma. Colonies of Staphylococcus aureus are surrounded by a halo of precipitated fibrin. When foods such as dairy products contain large numbers of egg yolk – negative strains of S. aureus, the PPSA agar has the advantage over egg yolk containing media such as Baird-Parker agar that fewer suspect colonies have to be confirmed.
Comparison of talc-Celite and polyelectrolyte 60 in virus recovery from sewage: development of technique and experiments with poliovirus (type 1, Sabin)-contaminated multilitre samples
Authors: Sattar Syed A. , Westwood J. C. N.
Published: April 2010

For virus recovery from sewage, a mixture of talc and Celite was tested as a possible inexpensive substitute for polyelectrolyte 60(PE 60).After adjustment of pH to 6 and the addition of 45–60 plaque forming units (PFU)/ml of poliovirus type I(Sabin) to the sewage sample under test, 100 ml of it was passed through either a PE 60 (400 mg) or a talc (300 mg)–Celite (100 mg) layer; the layer-adsorbed virus was eluted with 10 ml of 10% fetal calf serum (FCS) in saline (pH 7.2).In these experiments, PE 60 layers recovered 73–80% (mean 76%) of the input virus. In comparison, virus recoveries with the talc–Celite layers were 65–70% (mean 68%).Passage of 5 litres of raw sewage (containing 50 to 1.26 × 105 PFU/100 ml of the poliovirus) through the talc (15 g)–Celite (5 g) layers and virus elution with 50 ml of 10% FCS in saline gave virus recoveries of 33–63% (mean 49%).Except for pH adjustment and prefiltration through two layers of gauze to remove large solids, no other sample pretreatment was found to be necessary. Application of this technique to recovery of indigenous viruses from field samples of raw sewage and effluents has been highly satisfactory.
The effects of pH and temperature on the assay of superoxide dismutase
Authors: Buchanan A. G. , Lees H.
Published: April 2010

A simple and reliable method for the measurement of superoxide dismutase (EC 1.15.1.1) activity is described. The method is based on a linear inhibition of the reduction of acetylated cytochrome c by superoxide dismutase.
Heterotrophic activities of bacterioneuston and bacterioplankton
Authors: Dietz A. S. , Albright L. J. , Tuominen T.
Published: April 2010

Numbers of viable bacteria as indicated by colony-forming units (CFU), microbial adenosine triphosphate levels, dissolved organic carbon (DOC), particulate organic carbon and nitrogen (POC and PON), glucose concentration, heterotrophic potential (Vmax) and in situ heterotrophic activity (Vn) of near-surface microlayer samples (70–80 μm depth), the neuston, and bulk column water samples (0.2–1.5 m depth), the plankton, of several natural waters were compared. DOC and glucose concentration values of near-surface and bulk water were similar, whereas POC and PON values of the near-surface were normally one order of magnitude greater than those of bulk water. Viable counts were generally greater in the neuston, but ATP levels were greater in the plankton. Comparative values of total heterotrophic potentials and heterotrophic activities fluctuated greatly. Heterotrophic potential per CFU of the neuston was 33% of that of the plankton; neuston heterotrophic activity per CFU was 10% of that of the plankton. These data suggest that neustonic heterotrophic bacteria are not as metabolically active as their planktonic counterparts and that they are under greater stress at the near-surface than in the column water.
Activation and killing Dictyostelium discoideum spores with urea
Authors: Cotter David A. , O'Connell Richard W.
Published: April 2010

The optimal conditions for activation of Dictyostelium discoideum spores are an 8 M urea treatment for 30 min. The lag between activation and swelling is 45 min. Lower concentrations of urea do not activate entire spore populations. Incubating spores in 8 M urea for 60 min or treatment with 10 M urea for 30 min results in a lengthening of the post-activation lag and a decrease in the final percentage of germination. Urea-activated spores can be deactivated by azide, cyanide, osmotic pressure, and low-temperature incubation.Activated spores do not germinate if incubated in 1 M urea for 24 h but will complete germination upon resuspension in urea-free buffer. Shocking spores at 45 °C in 8 M urea or incubating spores in 4–8 M urea for 10 h at 23.5 °C causes inactivation. When suspended in urea-free buffer, a larger percentage of these dead spores release spheroplasts through a longitudinal split in the spore case. Sequential enzyme treatment of spheroplasts with cellulase and promise causes them to release lysable protoplasts. The data of these experiments suggest that shedding of the outer and middle wall layers during physiological spore swelling may be a physical process rather than an enzymatic one.
Isolation of Klebsiella pneumoniae from lake water
Authors: Campbell Lucy M. , Michaels Glenda , Klein Richard D. , Roth Ivan L.
Published: April 2010

The question of the importance of aquatic borne Klebsiella pneumoniae to public health has been argued as the organism has appeared often in both polluted effluents and oligotrophic systems. Using a selective medium, double violet agar, which also differentiates K. pneumoniae from other organisms found in aquatic systems, we sampled water from three ponds and a large man-made lake, over a 3-month period. Results indicate that K. pneumoniae can be isolated consistently and in high numbers from eutrophic waters even when environmental stress reduces total numbers, but that isolations from cleaner waters are erratic. We conclude that mere isolation of the organism as an occasional contaminant probably does not present a hazard to public health.
Cellulase induction and the use of cellulose as a preferred growth substrate by Cellvibrio gilvus
Authors: Breuil Colette , Kushner D. J.
Published: April 2010

Cellvibrio gilvus produced cellulase when grown in the presence of cellulose or carboxymethyl cellulose (CMC) but not when grown in the presence of glucose or cellobiose. This was so whether or not these compounds were the sole carbon sources present. Repeated addition of small amounts of glucose prevented cellulase formation in the presence of cellulose. It is concluded that cellulose and CMC induce cellulase formation and glucose and cellobiose repress it. Cellulose stimulated growth when added to organic media. Physical contact between cells and cellulose fibres was necessary for both cellulase induction and growth stimulation. If cellulase induction was prevented by glucose, cellulose did not stimulate growth.
The effects of culture concentration and age, time, and temperature on bacterial attachment to polystyrene
Authors: Fletcher Madilyn
Published: April 2010

The attachment of a marine pseudomonad to polystyrene was found to be dependent upon (a) culture concentration, (b) the time allowed for attachment, (c) the growth phase of the culture, and (d) temperature. The number of attached cells increased with both culture concentration and the time allowed for attachment, until the attachment surface approached saturation. The number of cells which attached and the rate of attachment was greatest with log-phase cultures, and progressively decreased with stationary and death-phase cultures. A temperature of 3 °C ± 1 noticeably decreased the proportion of stationary phase cells which attached, compared with cells at 20 °C ± 1. These results can be described by a model based on physicochemical adsorption, which suggests that non-biological processes may play a major role in the initial events of bacterial adhesion.