bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphological characteristics of a spirochete present in activated sludge
Authors: Deinema Maria H.
Published: April 2010

A free-living spirochete has been found in the activated sludge of purification plants in Amsterdam. A partial enrichment of the spirochete could be obtained with a passage through a thin layer of water agar. The morphology of this spirochetal strain does not fit into one of the described genera in Bergey's Manual. The cells have many regular primary coils on which broad secondary coils are superimposed and the protoplasmic cylinder is tightly wound around an axistyle.
Presumptive identification of Klebsiella pneumoniae on m-FC medium
Authors: Stramer Susan L.
Published: April 2010

Klebsiella pneumoniae is a human and animal pathogen frequently encountered in the environment. The membrane-filtration method utilizing m-FC medium for the detection of fecal coliforms yields a colony type easily distinguishable as K. pneumoniae. These colonies appear as atypical light blue, nucleated, mucoid colonies differing considerably from the typical dark blue fecal coliform colonies.
Mycophenolic acid is produced during balanced growth of Penicillium brevicompactum
Authors: Nulton Carter P. , Campbell Iain M.
Published: April 2010

When Penicillium brevicompactum is grown on Czapek Dox medium in the surface or sub merged mode as batch or continuous-flow cultures, mycophenolic acid is produced. Unlike the classical secondary metabolic system, 6-methylsalicylic acid production by P. patulum, mycophenolic acid is formed independently of dilution rate in a flow system. Discounting the possibility that strains of P. brevicompactum that produce mycophenolic acid are mutants defective in the control of secondary metabolite biosynthesis, we conclude that mycophenolic acid production is not regulated as part of a non-vegetative genome. An invertase (EC 3.2.1.26) activity has been encountered in both P. brevicompactum and P. patulum.
Mycoparasitism of oospores of Pythium and Aphanomyces species by Hyphochytrium catenoides
Authors: Ayers W. A. , Lumsden R. D.
Published: April 2010

Oospores of Pythium myriotylum in nonsterile soil extracts became invaded by a fungus that was isolated and identified as Hyphochytrium catenoides. Sporangia of H. catenoides formed as spherical or ovoid lobes within the Pythium oospore and as radial catenulate swellings on agar media. In water, these sporangia formed short exit tubes through which anteriorly monoflagellated zoospores were released. Oospores of P. myriotylum and Aphanomyces euteiches placed in suspensions of motile zoospores of H. catenoides became extensively invaded within 48 h. Oospores of Pythium aphanidermatum and P. ultimum were also attacked, but these species were less susceptible to invasion than was P. myriotylum. Sporangia, hyphae, and zoospores of the Pythium spp., A. euteiches, and several other phycomycetes were not observed to be invaded. Zoospores of H. catenoides were formed and released in water adjusted to pH 5.0–7.0 and at temperatures of 10–35 °C, but were produced most abundantly and were most highly motile at pH 6.0–7.0 and at 20–30 °C. The roots of several crop plants did not appear to be parasitized by H. catenoides. Oospores of P. myriotylum, P. aphanidermatum, and P. ultimum in moist soil artificially infested with these species and H. catenoides were destructively invaded by the mycoparasite. Its presence in several soils and its ability to reproduce quickly in its parasitic stage suggest that H. catenoides may play a role in the natural decline of susceptible Oomycetes in soil.
Characterization of SPβ: a temperate bacteriophage from Bacillus subtilis 168M
Authors: Warner Fred D. , Kitos Gary A. , Romano Martin P. , Hemphill H. Ernest
Published: April 2010

Bacillus subtilis 168M is lysogenic for a temperate bacteriophage called SPβ. The virus head is 76 m wide by 82 m long and the tail measures 12 by 358 m. The DNA molecular weight is 62 million. SPβ is spontaneously released at low levels in cultures of B. subtilis 168M, and can be induced at higher levels by treatment with mitomycin C or N-methyl-N′-nitro-N-nitroso-guanidine.
The basis for avirulence in a prototrophic strain of Penicillium expansum
Authors: Brock Philipa D. , MacNeill B. H.
Published: April 2010

Pathogenesis of apple by the facultative parasite Penicillium expansum was critically dependent upon certain physiological events during the primary stages of spore germination. A comparison of two prototrophic isogenic strains of the fungus, one of which was virulent, the other avirulent, revealed that both produced an apple-macerating factor when the spores germinated in vitro. However, germination and growth of the avirulent strain in apple extract and in apple fruit was significantly lower than with the virulent strain. This contrasting behaviour was attributed to the differential sensitivity of the two strains to an inhibitory substance of host origin. Radioactive isotope studies indicated that, with the avirulent organism, the inhibitor interfered with the incorporation of 14C into RNA from labelled [6-14C]orotic monohydrate during germination; under similar conditions RNA synthesis by the virulent strain was stimulated. Incorporation of 14C into protein from labelled [U-14C]L-arginine monohydrochloride was not influenced by the inhibitor, nor was the differential sensitivity of the two strains attributable to differences in respiration, although apple extract greatly reduced the evolution of 14CO2 from [1-14C]D-glucose in both strains. The inhibitor, which was water-soluble and dialyzable, appeared to have a fundamental effect upon the metabolism of the spores in the initial stages of germination, and is postulated to be a primary determinant in the virulence of P. expansum. The data support the hypothesis that the mechanism controlling the pathogenicity of a prototroph may be distinct from that which governs the basic nutrition of the organism.
Electrophoretic comparisons of mycelial enzymes from aflatoxin-producing and non-producing strains of Aspergillus flavus and Aspergillus parasiticus
Authors: Schmidt Anita L. , Curtis C. R. , Bean G. A.
Published: April 2010

Buffered mycelial extracts were prepared from 20 isolates of Aspergillus flavus Link ex. Fries and four isolates of Aspergillus parasitions Speare, including aflatoxin-producing and non-producing strains within each species. The extracts were tested for activity of various enzymes after separation by polyacrylamide gel-slab electrophoresis. Aspergillus spp. were most readily distinguished by the bands of α-esterase (EC 3.1.1.2), β-esterase (EC 3.1.1.1), and peroxidase (EC 1.11.1.7). For each isolate, the relative mobilities were determined for the various multiple-molecular forms of all three enzymes. The isolates were then compared on the basis of these relative mobilities by using a simple index of similarity to construct a single-linkage dendrogram. No distinct differences in enzyme patterns were detected between aflatoxin-producing and non-producing isolates. However, patterns of similarity or groups were indicated in the dendrogram which suggested some degree of physiological relationship.
A comparison of quantitative methods for measuring yeast flocculation
Authors: Calleja G. B. , Johnson Byron F.
Published: April 2010

Two quantitative objective methods for measuring flocculation of a yeast culture were com pared and correlated with subjective estimation by eye. One method involved counting in a haemocytometer the number of free cells (i.e., cells not found in flocs) and then the total number of cells after complete deflocculation by pronase. The number of cells in flocs was derived by subtracting the number of free cells from the total number of cells. The other method made use of the decrease in turbidity of a flocculated culture on standing. Gross flocs settled to the bottom of a tube within 5 min. The decrease in turbidity was measured by a photoelectric colorimeter. The difference in turbidity readings between 0 and 5 min was assumed to represent the turbidity component due to cells in flocs. The methods were appropriately applicable to monitoring the time course of sex-directed flocculation of the fission yeast Schizosaccharomyces pombe. A culture at maximum flocculation contained 500 gross flocs ml−1 which represented up to 70% of the total number of cells. A typical primary floc occupied a volume of 1 × 10−4 ml and contained 1 × 105 cells.
A fluorescence-staining method for microscopically counting viable microorganisms in soil
Authors: Mayfield C. I.
Published: April 2010

A fluorescence-staining method using the magnesium salt of 1-anilino-8-naphthalene sulfonic acid is described. It allows the numbers and types of viable microorganisms in soil sections to be determined by direct microscopy. About 8% of the bacteria in the soils studied were able to divide when a nutrient solution was applied. A higher percentage of the fungal propagules in these soils were viable. The effects of environmental factors, chemical compounds, and soil amendments on the ability of soil microorganisms to undergo division or mycelial extension in situ can also be determined.
Frequency of hepatitis B surface antibody (anti-HBs) in various Canadian populations as measured by modified solid-phase radioimmunoassay
Authors: Bishai F. R. , MacMillan S. , Dempster G. , Rhodes A. J. , Spence L. , Wrobel D. M.
Published: April 2010

A short incubation solid-phase radioimmunoassay test was developed and used for the detection of hepatitis B surface antibody (anti-HBs) in the sera collected from patients recovering from hepatitis B infection, health care personnel, staff and residents of an institution for the mentally retarded and in pregnant and non-pregnant women in Ontario. The test was slightly more sensitive than the passive haemagglutination method (PHA) and less sensitive than the Ausab Radioimmunoassay technique (RIA).The prevalence of anti-HBs in different populations tested ranged from 0 to 44.3%. They were classified according to the statistical analysis into three main categories: low, intermediate, and high risk. Students and administrative staff were in the low-risk category, Microbiology, histology, pathology technologists, renal dialysis staff, and the health care personnel responsible for the care of the institutionalized mentally retarded were in the intermediate-risk category. Pathologists, haematologists, and biochemists were in the high-risk category. The results showed that health care personnel who were exposed to blood or blood products had a higher frequency of anti-HBs than those who were not exposed.
Observation of the swarming of Proteus mirabilis with scanning electron microscopy
Authors: VanderMolen Gail E. , Williams Fred D.
Published: April 2010

Proteus mirabilis was examined on an agar surface with scanning electron microscopy after critical-point drying. Groups of swarm cells were covered by a thin cocoon. The cocoon appears identical with the slime found covering the agar surface behind rafts of swarm cells. Swarm cells possessed numerous appendages that resemble peritrichous flagella in number, size, location, and attachment to the cells.
Nicotinamide adenine dinucleotide – independent formate dehydrogenase in Mycobacterium phlei
Authors: Deyhle Ronald R. , Barton Larry L.
Published: April 2010

Formate dehydrogenase activity (EC 1.2.1.2) has been demonstrated in cell-free preparations of Mycobacterium phlei by following the reduction of 2,6 dichlorophenolindophenol, thiazolyl blue tetrazolium, or equine cytochrome c. The reduction of equine cytochrome c was inhibited by 2-heptyl-4-hydroxyquinoline-N-oxide. Neither nicotinamide adenine dinucleotide nor nicotinamide adenine dinucleotide phosphate were reduced by this formate dehydrogenase. The enzyme was constitutive and associated with the particulate fraction. The greatest level of activity was observed at pH 9.0, with 8 mM formate, and with extracts of cells taken from the log phase of growth. Formaldehyde, hypophosphite, nitrate, and bicarbonate all inhibited the oxidation of formate.
Effects of clear-cutting on the composition of bacterial populations of northern spruce forest soil
Authors: Niemelä Seppo , Sundman Veronica
Published: April 2010

This paper concerns the microbiological part of an investigation, the goal of which is to describe the biological changes in coniferous forest soil upon clear-cutting in a northern (66°20′ N) moraine area where reforestation after clear-cutting had been met with difficulty. The zoological part of the work has been published elsewhere. Clear-cut sites of increasing age (4, 7, and 13 years) were investigated and compared with a forest area where no cutting of timber had been done for 120 years.A total of 684 random isolates of heterotrophic bacteria from pooled samples of the sites investigated were passed through 36 biochemical tests. The data were condensed by the aid of factor analysis, and a comparison of the populations was based on squared Euclidean distances between population centroids in a seven-dimensional factor space.The most marked population changes followed a course in which frequencies of some population characteristics became increasingly different until 7 years after clear-cutting, with regression towards the control clearly evident after 13 years. Disturbances of shorter duration were also relatively common, with maximal changes observed in the 4-year samples, and with a complete recovery after 7 years.The mineral soil populations seemed to undergo greater changes than the humus populations.The most distinct changes believed to be due to clear-cutting were the short-term relative increase of organisms producing acid from sucrose and dissolving CaHPO4, and a long-term increase of lipolytic and caseolytic, rhamnose-negative organisms; both in the mineral soil layer. In the humus layer, a short-term increase of lipolytic and of rhamnose-positive organisms seemed to take place.
Requirements for the rapid conversion of macroconidia of Fusarium sulphureum to chlamydospores
Authors: Barran Leslie R. , Schneider Edward F. , L.Seaman W.
Published: April 2010

Chlamydospores of Fusarium sulphureum were formed within 72 h by incubating macroconidia at 37 °C in stationary culture in a medium containing mannitol and inorganic salts. The conversion process was dependent on inoculum level, temperature, aeration, and the presence of an external source of nitrogen and carbon. Chlamydospore formation was not inhibited by an uncoupler of oxidative phosphorylation, 2.4-dinitrophenol, or by inhibitors of bacterial cell wall synthesis; however, it was affected by inhibitors of respiration and of protein and chitin synthesis.
The role of metabolic energy in the lethal action of basic proteins on Candida albicans
Authors: Olson Vernon L. , Hansing Ronald L. , McClary Dan O.
Published: April 2010

Comparative studies were made on the destructive effects of certain basic proteins on a strain of Candida albicans and two of its respiration-impaired mutants. Both by direct plate counts of survivors and by quantitative ultraviolet spectrophotometric analyses of released cellular constituents, the respiration-impaired mutants were less vulnerable to the destructive actions of the basic proteins than were ordinary wild-type cells. The lethal incidence and the ultraviolet absorbing cellular substances released from wild-type cells by the proteins were markedly decreased in the presence of the oxidative phosphorylation uncouplers sodium azide, 2,4-dinitrophenol, and salicylanilide and approximately equal to the effects produced on an oxidative phosphorylation mutant not treated with the uncouplers. The heightened resistance of a culture through mutational or chemical impairment of its respiratory system suggests a role of metabolic energy in the destructive action of various basic proteins on yeast cells.
Ontogeny of lipid bodies in the endoplasmic reticulum of Fusarium sulphureum
Authors: Schneider Edward F. , Seaman W. L.
Published: April 2010

The ontogeny of lipid bodies during the differentiation of conidial cells to chlamydospores in Fusarium sulphureum (F. sambucinum f. 6) is described. The lipid bodies are first seen as electron-transparent areas within dilated cisternae of the endoplasmic reticulum (ER). One or more such cisternae may be formed within a strand of ER. The intracisternal lipid bodies are bounded by a unit membrane derived from the double membrane of the ER. The dilated cisternae increase in size and remain electron-transparent; however, some electron-dense granular material is present in the lipid bodies. The limiting unit membrane is visible throughout development of the lipid body; however, in mature chlamydospores the membrane is obscured by a broad band of electron-dense material which may provide protection to the stored lipids during adverse environmental conditions. The system of lipid body development in F. sulphureum is discussed in relation to those described for higher plants.
Characterization of an immunogenic fraction of Pasteurella multocida culture filtrates
Authors: Srivastava Kunwar K. , Foster John W.
Published: April 2010

An immunogenic fraction (IF) of Pasteurella multocida strain P-1059 was separated from culture filtrate by Sephadex gel filtration. Additional fractionation of IF with aqueous ether resulted in the glycoprotein-like preparation (GLP) while extraction with aqueous phenol provided the lipopolysaccharide-like preparation (LPP). The unextracted IF contained carbohydrate, protein, and lipid; the GLP contained carbohydrate and protein; and the LPP contained carbohydrate and lipid. The GLP was maximally protective for mice against homologous challenge, and was medially toxic in rabbit skin when compared to the other culture-filtrate preparations; the LPP was maximally toxic in rabbit skin, and was least protective for mice; and the unextracted IF was medially protective for mice, and was least toxic in rabbit skin.
Effects of proteolytic enzymes on invertase secretion in sphaeroplasts of Saccharomyces: inhibition by trypsin
Authors: Holbein Bruce E. , Kidby Denis K.
Published: April 2010

Exogenously added trypsin arrested invertase secretion by sphaeroplasts of Saccharomyces strain 1016. The mechanism of inhibition is presumed due to attack on plasma membrane protein(s). Gross membrane damage by trypsin was not apparent, as evidenced by the absence of leakage of intracellular alkaline phosphatase, after trypsin treatment. Trypsin treatment did induce an increased sensitivity to lysis, observed only when changes in osmotic pressure were made and fresh glucose added. While synthesis of invertase was eventually inhibited by trypsin, a greater than twofold increase in internal invertase was observed, due to complete inhibition of secretion. This is the first report of the uncoupling of synthesis and secretion in yeast.
Manganese-mediated morphogenesis in Penicillium claviforme and Penicillium clavigerum
Authors: Tinnell Wayne H. , Jefferson Betty L. , Benoit Robert E.
Published: April 2010

The colonial morphology and growth of Penicillium claviforme and P. clavigerum in manganese-deficient, defined medium, were examined with and without manganese supplementation. In unsupplemented medium rendered free of manganese through treatment with a chelating resin, P. claviforme grew but did not produce coremia. Similar results were obtained for P. clavigerum on media devoid of added manganese. However, when these media were supplemented with optimal concentrations of manganese both fungi produced coremia. The presence of manganese in various colony sections of P. claviforme was determined using neutron activation analysis. Maximal accumulation occurred in the conidia.
A xanthine-negative, melibiose-positive species of Streptomyces
Authors: Bakerspigel A.
Published: April 2010

The organism VH/CN-71 which had been isolated from a growth in a cat and described initially as an "unusual strain of Nocardia" is a streptomycete. This organism can also produce acid from melibiose although it is unable to decompose xanthine. Its sporophores are short, hooked, curved, or open-looped with extended spirals. Present data suggest that VH/CN-71 may belong to the "flavus" series of Streptomyces.
The attachment of bacterial spinae
Authors: Willison J. H. M. , Easterbrook K. B. , Coombs R. W.
Published: April 2010

Spinae are attached to protease-sensitive structural proteins in the external surface of the outer membrane. Agents and (or) treatments affecting ionic, hydrophobic, or hydrogen bonds are ineffective in releasing spinae from bacteria. As judged by thin-sectioning and freeze-fracturing techniques, the outer membrane is not modified at the attachment site to a detectable extent, and the other surface layers are not involved. The attachment of spinae is thus differentiated from that of flagella.
Influence de la pénétration de la lumière solaire sur le développement des bactéries phototrophes sulfureuses dans les environnements marins
Authors: Matheron Robert , Baulaigue Renee
Published: April 2010

Bottles of medium were inoculated with both strains of Chromatiaceae and Chlorobiaceae (mixed cultures) and immersed at different depths in the marine coastal waters of the Marseilles basin (France). After development, the in vivo absorption characteristics of the cells show the effect of the daylight penetration on the selective growth of phototrophic sulfur bacteria. With depth, sunlight selects Chlorobiaceae rich in brown carotenoid pigments to the detriment of Chromatiaceae.
The effects of light and tyrosinase during sclerotium development in Sclerotium rolfsii Sacc.
Authors: Miller R. Michael , Liberta Anthony E.
Published: April 2010

Some effects of light on morphogenesis in Sclerotium rolfsii Sacc. were studied. Physiological competence to visible light developed during the first 120 h after inoculation, with an optimum sensitivity phase between 84 and 96 h that coincided with the leading hyphae reaching the edge of the Petri dish. Although sclerotial initials were produced in dark-grown cultures, light was necessary for the continuation of the developmental and maturation phases of sclerotial morphogenesis. Tyrosinase activity (o-diphenol: oxygen oxidoreductase, EC 1.10.3.1) was detected during sclerotial formation and the pH and temperature optima for this polyphenol oxidase in vitro were about 6.0 and 45 °C respectively. The enzyme was inhibited by cysteine. Similar activity levels of tyrosinase were obtained in blue and 'white' light-grown cultures but in red light activity was comparable with that of dark-grown cultures. Laccase activity was not detected at any stage of development.
Selection of a stable clone of the MVPK-1 fetal porcine kidney cell for assays of foot-and-mouth disease virus
Authors: Dinka Stephen K. , Swaney Lois M. , McVicar John W.
Published: April 2010

The MVPK-1 cell line, derived from fetal porcine kidney cells, supports the replication of foot-and-mouth disease (FMD) virus. The cell line was adapted to grow in medium containing 5% bovine serum. The susceptibility of the adapted cells decreased as they aged at 37 °C. Various clones were isolated from the adapted cells and their growth characteristics and sustained susceptibility to FMD virus were compared. Clone 7 maintained uniform susceptibility to FMD virus over a 3-day period at 37 °C and proved superior to other clones in the characteristics studied. The clone has maintained satisfactory susceptibility to FMD virus through 40 subcultures. Clone 7 can replace primary bovine kidney cells for routine viral assays, but cannot detect as much FMD virus in animal specimens as primary bovine kidney, bovine thyroid, or swine kidney cells.
Denitrification by N2-fixing Spirillum lipoferum
Authors: Neyra C. A. , Döbereiner J. , Lalande R. , Knowles R.
Published: April 2010

Forty-nine N2-fixing strains of Spirillum lipoferum isolated from a wide range of plant roots and soils were examined for reduction of NO3−. All strains reduced NO3− to NO2−. Thirty of the strains further reduced NO2− with production of gas. Examination of representative strains of the putative denitrifiers showed that they produced both N2O and C2H4 in the presence of 0.1 atm of C2H2. Strains which did not reduce NO2− with production of gas produced C2H4 but not N2O in the presence of C2H2. This is the first report of a N2-fixing bacterium able to bring about denitrification of NO3−.
Cellular bodies in developing chlamydospores of Thielaviopsis basicola
Authors: Clough K. S. , Schneider E. F. , Seaman W. L.
Published: April 2010

The development of chlamydospores of Thielaviopsis basicola from hyphal cells involves the thickening and pigmentation of the cell wall. Electron microscope studies showed that membrane-bound cellular bodies appearing in the cytoplasm of differentiating cells developed from dilated cisternae in the endoplasmic reticulum. Within the membrane-bound bodies, vesicles of up to 0.2-μm diameter were observed which contained electron-dense particles. Vesicles resembling those seen in the cellular body were also present in the cytoplasm close to the plasmalemma. In newly formed chlamydospore cells where wall thickening was complete, the cellular bodies showed loss of internal organization, and most of the vesicles disappeared, leaving a structure resembling a vacuole. The cellular bodies were not present in undifferentiated hyphae or in mature chlamydospores.
A modified bioassay for heat-stable Escherichia coli enterotoxin
Authors: Stavric S. , Jeffrey D.
Published: April 2010

Infant mice were injected orally with preparations containing Escherichia coli heat-stable enterotoxin (ST) and Evans blue dye, and incubated at 22 °C. With enterotoxin-positive samples, the stomach was distended and contained essentially all of the dye. With enterotoxin-negative samples, the stomach remained normal in size and the dye passed freely into the intestines. The time required to obtain the maximum ratio of gut weight to body weight varied from 30 to 90 min and was dependent upon the concentration of enterotoxin. Heat-labile enterotoxin (LT) had no effect during this period.Based on these findings, the mouse incubation time was reduced from 4 h to 90 min, and the heating of test samples was retained only for confirmation of ST. The location of the dye and stomach distention served as an indicator of positive responses to ST. Incubation of the mice at room temperature (22 °C) was found satisfactory.
Effects of temperature on the macromolecular composition and fine structure of psychrophilic Arthrobacter species
Authors: Gounot Anne-Monique , Novitsky Thomas J. , Kushner Donn J.
Published: April 2010

A facultatively psychrophilic bacterium, Arthrobacter SI 55, grows at 20 °C, but growth, as measured by increase of viable cell count, is inhibited at 32 °C. Corresponding temperatures for an obligate psychrophile, Arthrobacter glacialis SI 137, are 10 °C and 19–20 °C. At the higher temperatures for each organism increases of cell mass, as measured by turbidity and of DNA, RNA, and protein, were not inhibited. At the upper temperatures, fewer septa were formed in Arthrobacter SI 55, and cells appeared as distorted filaments with irregular branches. Arthrobacter glacialis grew as single cells at the lower temperature, but as clumps of coccoid cells with well marked septa at the higher temperature. It appears that in Arthrobacter SI 55 septum formation may be inhibited at the higher temperature. In contrast, in A. glacialis septation occurs but the cells do not separate.
Inhibition of gas vesicle production in Microcyclus aquaticus by L-lysine
Authors: Konopka Allan E.
Published: April 2010

The timing and degree of gas vesicle production in Microcyclus aquaticus was affected by nutritional conditions. If 50 μg L-lysine/ml was added to a glucose – mineral salts medium (DM), the organism did not form gas vesicles. This effect was specific for L-lysine, as neither D-lysine nor meso-diaminopimelic acid prevented gas vesicle production. Cells grown in the presence of L-lysine did not contain any immunologically detectable gas vesicle protein, which indicates that L-lysine affects expression of the structural gene for the gas vesicle protein rather than assembly of the protein into gas vesicles. The addition of L-lysine to cultures in DM did not immediately decrease the rate of gas vesicle assembly, nor did the removal of cells from DM plus L-lysine to DM result in immediate gas vesicle production. Gas vesicle production was also affected by the addition of L-threonine or L-cysteine to culture media or by an increase in the medium's ionic strength. These results are discussed in relation to the aspartic acid pathway of amino acid biosynthesis and effects upon the intracellular L-lysine concentration.
The significance of cAMP induced alterations in the cellular structure of Phycomyces
Authors: Tu J. C. , Malhotra S. K.
Published: April 2010

Effect of cyclic AMP (cAMP) on Phycomyces blakesleeanus was studied by growing sporangiospores on glucose–asparagine agar or liquid medium containing three different levels of cAMP (10, 20 and 40 μM) in addition to the control (no cAMP added). The response of Phycomyces to the exogenous cAMP concentration in the medium is as follows: (1) the time required for germ tube emergence is reduced; (2) the diameter of the mycelium is increased (sometimes more than 10 times) and frequency of branching is also increased; (3) the cell wall of the mycelium is thickened (in some cases more than 5 times); (4) the glycogen in the cytoplasm is decreased as visualized in thin sections and also demonstrated in biochemical quantitation; and (5) the distribution of intercalated membranous particles (Imp) on plasma membrane is altered and this can be easily detected in freeze-fractured replica. Such a change in Imp is seen in the formation of small clusters of aggregated particles on the plasmic half (PF) and craters on the complementary exoplasmic half(EF)of the plasma membrane. Although the mechanism of cAMP action requires further exploration, it is possible that the addition of cAMP to the culture medium leads to degradation of glycogen and enhancement of chitin synthesis since the cell wall is largely composed of chitin. The alteration in Imp may be related to a change in the activity of chitin synthetase which is a plasma membrane-bound enzyme.
Effects of exogenous fatty acids on growth and enterotoxin B formation by Staphylococcus aureus 14458 and its membrane mutant
Authors: Altenbern Robert A.
Published: April 2010

Growth and enterotoxin B (SEB) formation by Staphylococcus aureus 14458 and its membrane mutant can be depressed or stimulated by addition of graded amounts of saturated or unsaturated fatty acid mixtures. Under some conditions depression of SEB formation is separable from growth inhibition. Individual fatty acids most active in altering growth and (or) SEB production have been identified. Small amounts of unsaturated fatty acid mixture not only antagonize some effects of saturated fatty acid mixtures, but also appear to potentiate inhibition of growth and SEB formation by the saturated fatty acid mixture. 2-Adamantanone, a compound which increases cell membrane fluidity, strongly suppresses SEB formation while stimulating growth. The results are discussed in relation to possible effects of exogenous fatty acids on the composition of membrane phospholipids and attendant changes in SEB production.
Partial purification and some properties of a neutral sulfhydryl and an acid proteinase from Entamoeba histolytica
Authors: McLaughlin John , Faubert Gaetan
Published: April 2010

The partial purification of two intracellular proteinases from the protozoan parasite Entamoeba histolytica is reported. One of these enzymes is an acid proteinase exhibiting maximum activity at pH 3.5 (hemoglobin substrate), is little affected by a range of inhibitors or activators, and is presumed to be similar to cathepsin D. Also present is a neutral proteinase exhibiting optimum activity at pH 6.0 (azocasein) but only poorly hydrolyzing either hemoglobin or serum albumen. This latter enzyme displayed no metal ion requirement, but was markedly inhibited by thiol-blocking agents and activated by free sulfhydryl-containing compounds.
Degradation of natural and Kraft lignins by the microflora of soil and water
Authors: Crawford Don L. , Floyd Suellen , Pometto III Anthony L. , Crawford Ronald L.
Published: April 2010

The comparative rates of microbial degradation 14C-lignin-labeled lignocelluloses and 14C-Kraft lignins were investigated using selected soil and water samples as sources of microorganisms. Natural lignocelluloses containing 14C primarily in their lignin components were prepared by feeding plants uniformly labeled L-[14C]phenylalanine through their cut stems. 14C-Kraft lignins were prepared by pulping lignin-labeled lignocelluloses. Rates of lignin biodegradation were determined by monitoring 14CO2 evolution from incubation mixtures over incubation periods of up to 1000 h. Observed rates of lignin degradation were slow in all cases. Kraft lignins appeared more resistant to microbial attack than natural lignins, even though they were decomposed more rapidly during the first 100–200 h of incubation. Similar degradation patterns were observed in both soil and water. Individual samples, however, varied greatly in their overall rates of degradation of either lignin type. A Kraft-lignin preparation was separated into a variety of molecular weight fractions by column chromatography on LH-20 Sephadex and the biodegradability of the different molecular weight fractions determined. The lower molecular weight fractions of the Kraft lignin were decomposed at a significantly faster rate by the microflora of soil than were the fractions of higher molecular weight.
The identification, characterization, and mapping of a gene for flocculation in Saccharomyces sp.
Authors: Stewart G. G. , Russell I.
Published: April 2010

Genetic studies of a flocculent haploid strain of Saccharomyces have revealed the flocculation to be dominant and controlled at a single gene locus. The flocculation character of both hybrids and haploids derived from such hybrids appears to be influenced by the repression or derepression status of the culture. Mapping studies of this flocculation gene have revealed that it is linked to ade 1 and therefore located on Chromosome I. Consequently, this is a different gene to the three flocculation genes studied by other laboratories because they have found such genes to be unlinked to ade 1. The flocculation gene being discussed in this paper has been designated FLO4. FLO4 has been located 32–33 cM from the Chromosome I centromere and 37 cM from ade 1 (i.e., FLO4 is on the opposite side of the centromere to ade 1).
Effect of strain variation and growth phase of culture on dry weight and hexosamine content of cell wall layers of a marine pseudomonad
Authors: Sussman Richard , MacLeod Robert A.
Published: April 2010

Two variants of marine pseudomonad B-16 (ATCC 19855) differing in that one, variant 3, formed opaque colonies and the other, variant 7, formed translucent colonies were examined to determine if the variants differed in the amount and hexosamine content of their three outer cell wall layers. In both variants, the three outer layers of the cell wall, the loosely bound outer layer, the outer double-track layer, and the underlying (periplasmic space) layer contributed less to the dry weight of the cells when the cells were harvested in the stationary than in the logarithmic phase of growth. The hexosamine content of the layers of variant 3 increased dramatically as the cells went from the logarithmic to the stationary phase. The hexosamine content of the layers of variant 7 changed little by comparison. Thus cells of the variant which forms opaque colonies enrich the outer layers of their cell wall with hexosamine when grown to stationary phase.
Ribosomal ribonucleic acid cistron homologies among Hyphomicrobium and various other bacteria
Authors: Moore Richard L.
Published: April 2010

The extent of hybrid formation between the ribosomal ribonucleic acid (r-RNA) of Hyphomicrobium strain B-522 and deoxyribonucleic acid (DNA) from bacteria of 21 different genera was examined. Three generalized groupings were formed. Group I (72–100%) consisted entirely of other strains of Hyphomicrobium. Representatives of the genera Rhodopseudomonas, Chromatium, Caulobacter, Prosthecomicrobium, Rhodomicrobium, Hyphomonas, and Hyphomicrobium made up group II (49–69%). The remaining Gram-negative, Gram-positive, and cell wall – less bacteria fell into group III (12–40%). The taxonomic implications of these results are discussed.
Induction of encystment of Polysphondylium pallidum amoeba
Authors: Lonski Joseph , Pesut Nicholas
Published: April 2010

The induction of microcyst formation could be triggered in washed amoebae of the cellular slime mold Polysphondylium pallidum (strain-2) by the addition of 2 mM ethionine. Methionine at a ratio of 2:1 with ethionine would inhibit microcyst induction by ethionine. The involvement of polyamines in morphogenesis was also shown. Putrescine (0.02 to 0.1 M) induced the formation of microcysts, whereas spermidine (2 to 4 mM) was capable of causing a fourfold reduction in 0.05 M putrescine-induced microcysts but incapable of inhibiting microcyst induction by 0.08 M putrescine. Glycerol (0.5 M or 0.4 M) was also found to be an effective inducer of microcysts.
A rapid fluorescent focus-inhibition test for determining the neutralizing-antibody response to lymphocytic choriomeningitis virus
Authors: Thacker W. Lanier , Lewis Vester J. , Haller Gary J. , Baer George M.
Published: April 2010

Levels of neutralizing antibody to lymphocytic choriomeningitis (LCM) virus in the sera of 66 infected persons were assayed by a rapid fluorescent focus-inhibition test (RFFIT). The test was more sensitive than the mouse-neutralization (MN) test and could be completed in less than 24 h. The RFFIT titers were compared with titers obtained by the indirect fluorescent-antibody (IFA) and complement-fixation (CF) tests. Neutralizing antibody detected by the RFFIT remained positive after IFA, CF, and MN antibodies had disappeared. The RFFIT for detection of LCM antibody is specific and reproducible and seems especially useful for determining the incidence and epidemiology of LCM virus infections.
The relative ability of four rubella antigens to elicit blast cell transformation of lymphocytes from immune individuals
Authors: Rossier E. , Phipps P. H. , Webb T. , Polley J.
Published: April 2010

The ability of crude, semi-purified, and purified rubella antigens to elicit a specific and significant blast cell transformation of lymphocytes from immune individuals was investigated in 25 seronegative and 25 seropositive young adults.The type of preparation and the purity of the antigens were critical. Titration of the antigens by complement fixation or hemagglutination was of little value for selecting the best antigen which was a whole virion-purified antigen.
Improved procedure for selective enrichment of Shigella in the presence of Escherichia coli by use of 4-chloro-2-cyclopentylphenyl β-D-galactopyranoside
Authors: Park C. E. , Rayman M. K. , Stankiewicz Z. K.
Published: April 2010

A previously described procedure for the selective enrichment of Shigella in competition with E. coli has been modified and tested with a total of 48 strains of the four Shigella species. The new enrichment medium consists of 1.5-strength trypticase soy broth, 1 mM 4-chloro-2-cyclopentylphenyl β-D-galactopyranoside (CPPG), 0.25% lactose, and 0.1 M citrate buffer (pH 6.2). In competition with a 1000-fold higher population of E. coli than Shigella, 42 of 48 strains from the four species of Shigella were selectively enriched by the new method. Different lots of CPPG did not appear to affect the performance of the medium.
The cellular role of nitrogen in the biosynthesis of alkaloids by submerged culture of Claviceps purpurea (Fr.)Tul.
Authors: ↠eháček Z. , Desai J. D. , Sajdl P. , Pažoutová S.
Published: April 2010

Asparagine was a superior nitrogen source for clavine-alkaloid production in Claviceps purpurea. Its transport into the cell exceeded the cell's biosynthetic need for this amino acid. Asparagine entered the cell without degradation. This disturbed the relative pool sizes of various amino acids resulting in a change in the genetically determined ratio at which amino acids were utilized for protein synthesis. Overproduction of alkaloids (4500 μg.ml−1) may be associated with increased availability of tryptophan because of the enhanced assimilation of asparagine-derived ammonia via glutamine synthetase (EC 6.3.1.2). However, ammonium salts in the fermentation broth led to a depression of the alkaloid yield. Partial replacement of the ammonium salt by aspartic acid elevated alkaloid production.
Clostridium perfringens — specific lysin
Authors: Nakamura S. , Okada I. , Mizuno J. , Nishida S.
Published: April 2010

A mitomycin C induced lysate of Clostridium perfringens strain KZ219 was lytic to 50 strains of C. perfringens of types A–E, and three strains of C. plagarum. The lysin was active against only 2 out of 87 strains of 51 other clostridial species. The optimum pH of the lytic agent was 5.5. The activity was largely inactivated by proteolytic enzymes, and nearly completely inactivated by heating at 60 °C for 5 min.
Effects of temperature and antibiotics on appressorium formation in spores of Colletotrichum lagenarium
Authors: Tani Machiko , Ishida Norio , Furusawa Iwao
Published: April 2010

Effects of temperature (32 °C), cycloheximide, and blasticidin-S on spore germination and appressorium formation of Colletotrichum lagenarium were investigated. Temperature treatment at 32 °C, given just before the emergence of the germ tube 4 h after incubation at 24 °C, significantly inhibited appressorium formation. Cycloheximide (1 ppm) or blasticidin-S (7 ppm) appeared to have reversed the effect of 32 °C treatment by producing appressoria in 30% of the germinated spores.
Allantoinase and allantoicase synthesis in Pseudomonas aeruginosa
Authors: Rijnierse V. F. M. , Drift C. van der , Vogels G. D.
Published: April 2010

Allantoinase (allantoin amidohydrolase, EC 3.5.2.5.) and allantoicase (allantoate amidinohydrolase, EC 3.5.3.4) of Pseudomonas aeruginosa are inducible enzymes, whose syntheses are enhanced by the presence of allantoin, allantoate, ureidoglycolate, N-carbamoyl-L-asparagine, N-carbamoyl-L-aspartate, hydantoate, and diureidomethane. For each compound a specific ratio between the activities of allantoinase and allantoicase was obtained. The synthesis of these enzymes is not coordinately controlled. N-Carbamoyl-L-aspartate, hydantoate, and diureidomethane are gratuitous inducers.
A broth medium for production of a sporulation pigment in Streptomyces venezuelae
Authors: Tang T. , Bradley S. G.
Published: April 2010

A broth medium that supports growth and production of a sporulation pigment in Streptomyces venezuelae has been devised.
Natural occurrence of sterigmatocystin in in-shell pecans
Authors: Schroeder Harry W. , Hein Jr. Hugo
Published: April 2010

The natural occurrence of sterigmatocystin (S) in in-shell pecans is reported. Aspergillus versicolor was not isolated from contaminated samples. Incidence of A. flavus and A. glaucus, species known to produce sterigmatocystin under laboratory conditions, was high (43 and 35%, respectively). Isolation data suggest sterigmatocystin may have been produced by one or both of these species.
An evaluation of methods for obtaining mycelium-free oospores of Pythium aphanidermatum and P. myriotylum
Authors: Sauve R. J. , Mitchell D. J.
Published: April 2010

Sonication of aqueous suspensions containing mycelial fragments with or without oospores of Pythium aphanidermatum or P. myriotylum at 20% of the maximum intensity of a Biosonic III ultrasonic system for periods in excess of 100 s, or at 40,60, or 80% of maximum intensity for 20 s or longer resulted in suspensions free of viable mycelial fragments. Oospore germination was not affected after sonication at rates as high as 80% of maximum intensity for periods lasting as long as 60 s. In comparison with untreated controls, oospore germination of p. aphanidermatum or P. myriotylum was not affected by any of the following methods that were used for the preparation of oospore suspensions free of viable mycelial fragments: filtering or sonicating suspensions, treating suspensions with a cellulose–hemicellulase solution, or with a solution of commercial snail enzymes. Germination of P. aphanidermatum oospores was reduced by 78% and no germination of p. myriotylum oospores occurred after freezing the suspensions. Feeding mycelial mats to live water snails (Physa fontinalis) did not affect oospore germination of p. aphanider matum but increased germination of p. myriotylum oospores by 17% in vitro. At 25 oospores per gram of soil, only 7% of the tomato seedlings were infected after growth in soil infested with oospores of p. aphanidermatum that had been frozen, whereas 70–80% of the seedlings were infected after growth in soil infested at the same inoculum density with oospores exposed to the other treatments. No infection of rye seedlings occurred in soil infested with p. myriotylum oospores that had been frozen. A significantly higher level of infection of rye seedlings occurred with oospores of p. myriotylum that had been ingested by Physa fontinalis than with oospores that had been treated by the other methods. No infection occurred when tomato and rye seedlings were exposed to soil infested with mycelial fragments of 21-day-old cultures of p. aphanidermatum or P. myriotylum, respectively.
Sucrose density differences of Chlamydia psittaci 6BC in relation to its host
Authors: Kordová Nonna , Martin Caroline , Wilt John C. , Neuman Michael
Published: April 2010

Previous studies on Chlamydia psittaci 6BC propagated in different hosts have shown differences in cytotoxicity but no differences in the ultrastructure of the individual particles. It is shown here that the 6BC strain derived from yolk sac of infected chick embryo sedimented in sucrose gradients at lower densities than the 6BC strain derived from L-cells. Host-related modifications of lipid concentrations of the 6BC strains have been previously documented by others. It is thought that the phenomenon of host-induced modifications of physical properties of the agent might provide a new approach to the study of chlamydial pathogenicity.
The nature of Pseudomonas aeruginosa strain PAO bacteriophage receptors
Authors: Kropinski Andrew M. , Chan Lora , Jarrell Ken , Milazzo F. H.
Published: April 2010

Receptors for phages specific to Pseudomonas aeruginosa strain PAO were studied. Phages 16, 44, 109, F8, and PBI are lipopolysaccharide (LPS) specific as shown by neutralization tests. The PhI50's of the LPS, adsorption rate constants with strain PAO and the plaque morphologies of these five phages were quite similar. Phages 1214 and 7 also appear to be LPS-specific on the basis of host–range studies. Phage 73 is pilus-specific, while phages 21 and 68 fall into a group which does not attach to pili, flagella, or LPS. A theoretical approach to the interpretation of phage–cell interactions is presented.
The capsular network of Klebsiella pneumoniae
Authors: Cassone Antonio , Garaci Enrico
Published: April 2010

Attempts at improving chemical fixation for electron-microscopic observation of the capsule of Klebsiella pneumoniae were made. The capsule was preserved by using alcian blue – lanthanum and tris-(1-aziridinyl) phosphine oxide (TAPO) – aldehyde – osmium procedures. Despite the different retention of the overall capsular material and minor variations in morphological details, in both cases the interpretation of ultrastructural patterns suggested that the capsule be composed of a meshed network of thin polysaccharide fibrils radiating from the cell wall.This organization is in keeping with all recognized chemical properties of bacterial polysaccharide capsules or, at least, does not contradict them.Moreover, an effective preservation of bacterial structures other than capsule has been obtained, mostly in specimens fixed by the TAPO–aldehyde–osmium method, a fact which gives further reliability to the technical approach used for capsule visualization.