bluuebunny/crossref_metadata_2025 huggingface dataset:
Flocculation and adsorption of enzymes during growth of a moderate halophile, Micrococcus varians var. Halophilus
Authors: Kamekura Masahiro , Onishi Hiroshi
Published: April 2010

Flocculation of a moderate halophile, Micrococcus varians ATCC 21971, occurred during growth in complex medium containing 3 M NaCl and a concentration of MgSO4 and KH2PO4 greater than 40 and 14 mM, respectively. Extracellular nuclease activity was absent in the flocculated cultures. Repeated washing of flocs by Mg2+-free Tris buffer containing 3 M NaCl, lowering of pH value of floc suspension below 6.3, or addition of ethylenediaminetetraacetic acid resulted in complete dissociation of the flocs and release of Mg2+ ions as well as nuclease and amylase. Inhibition of extracellular enzyme production accompanied by flocculation appeared to be the result of adsorption of enzyme proteins to surfaces of the flocs, but not of inhibition of biosynthesis. Floc formation could also occur in media containing 18 mM CaCl2 and 3.0 mM KH2PO4, but the Ca flocs were not deflocculated by washing with Ca2+-free buffer, suggesting that the affinity of Ca2+ for cell envelopes was stronger than that of Mg2+. It was also observed that most halophilic Planococcus and Micrococcus flocculated in the presence of MgSO4 and phosphate but halophilic Pseudomonas, Acinetobacter, and Bacillus did not.
Etude ultrastructurale des processus de biodégradation. I. Pourriture blanche des feuilles de Hêtre (Fagus sylvatica L.)
Authors: Reisinger O. , Toutain F. , Mangenot F. , Arnould Marie-France
Published: April 2010

An electron microscopic study of beech leaf white rot shows a certain number of characteristic developmental stages which are identical whether the material is from in vitro experimentation or from natural incubation. Endowed with a cellulolytic property seemingly localized in the apical region only, hyphae of the white rot agent only traverse the plant cell walls. Subsequently, hyphae penetrate condensed protoplasmic residues and make them progressively transparent to electrons. During this discoloring process, a lethal factor of as yet unknown nature appears, affecting other microorganisms already present in the leaves. Phloem and xylem vascular bundles do not present notable ultrastructural modifications. Therefore, leaf discoloration is not due to an alteration of the xylem constituents but to changes having occurred in the condensed cytoplasmic residues of the dead tissues.
Effect of amino acid deprivation and chloramphenicol treatment on cell sizes of rel+ and relA− strains of Escherichia coli
Authors: Ishiguro Edward E. , Ramey William D.
Published: April 2010

The effects of inhibition of protein synthesis on the cell size distributions of rel+ and relA− derivatives of Escherichia coli K-12 were determined. Amino acid deprivation resulted in a reduction in the cell sizes of rel+ strains but not of relA− strains. Treatment with chloramphenicol (CAM) did not alter the size distributions of either rel+ or relA− strains except when they were rel+dap−. CAM treatment of rel+dap− strains resulted in an increase in cell size. It is proposed that these results reflect differences in the structures of the cell envelopes of rel+ and relA− bacteria.
Recherches sur la lysogénie chez Bacillus thuringiensis et B. cereus
Authors: Ackermann H.-W. , Smirnoff W. A.
Published: April 2010

Forty-eight strains of Bacillus thuringiensis and 12 strains of B. cereus were treated with ultraviolet light and mitomycin C. The former agent was the more effective inducer. Bacillus thuringiensis produces at least seven different phage particles with long, non-contractile tails. The frequencies of lysogeny and polylysogeny are 83 and 25% respectively. Morphologically defective phages occur in 25% of strains, whereas five of them produce low molecular-weight bacteriocins. One strain of B. cereus harbors "killer-particles." There is no apparent correlation between the presence of phage-like particles, phage sensitivity, and serotypes, biotypes, or the origin of B. thuringiensis strains.
Necrotrophic mycoparasitism of Ceratocystis fimbriata by Hirschioporus pargamenus (Polyporaceae)
Authors: Traquair James A. , McKeen Wilbert E.
Published: April 2010

Necrotrophic mycoparasitism by Hirschioporus pargamenus (Fr.) Bond. & Sing, on selected non-basidiomycetous fungi is characterized by rapid necrosis of host cytoplasm. Invagination of the host plasmalemma is followed by the production of a conspicuous extraplasmalemmal wall deposit. Necrosis is the result of disruption of membrane systems and is followed by the penetration of dead host cells. Pathogenesis involves an unidentified toxic substance excreted by the parasite. Contact is not essential.
The interaction of cholera toxin subunit A with cultured adrenal cells
Authors: Knoop Floyd C.
Published: April 2010

Subunits A and B of cholera enterotoxin were isolated by chromatography on a Bio-Gel P-60 column in the presence of 4% formic acid. The purity and biological activity of the isolated subunits was assessed by polyacrylamide disc gel electrophoresis and mouse adrenal cell assay, respectively.The specific uptake of isolated 125I-labeled subunits A and B, peptides A1 and A2 and bovine serum albumin (BSA) by cultured adrenal cells was investigated. The results indicate that iodosubunit A, or peptide A1 or A2, traverses the plasma membrane and is released to the cell cytosol. A significant portion of bound iodosubunits A or B was associated with the plasma membrane, suggesting the presence of specific membrane receptors.The biological activity of subunit A was determined by the mouse adrenal cell assay. The purified subunit caused a characteristic cellular change from epithelioid to rounded morphology. A 30-fold higher concentration of subunit A (on a mole/mole basis) as compared with native toxin was required for a maximum morphologic response. These results extend previous observations related to the bioactivity of subunit A of the cholera enterotoxin molecule.
Mycoviruses of Penicillium stoloniferum: influence of carbon–nitrogen nutrition upon replication
Authors: Detroy R. W. , DeMarini D. M. , Still P. E.
Published: April 2010

Carbon–nitrogen ratio experiments indicate that limiting nutrition not only hinders Penicillium stoloniferum host proliferation but reduces total PsV-F and PsV-S virus replication. Results of C-N experiments show a pH-induced autolysis and virus release at minimal C levels. Maximal PsV-F levels and biomass were obtained with glucose and sucrose as C sources. Oleic acid also yielded high biomass and PsV-F yields. Yeast extract was an excellent N source; 2.83 g dry weight biomass and 87 A260 units PsV-F after 96 h of growth. Other nitrogen sources, including amino acids, supported only minimal growth and virus replication. The autolysis phenomenon is pH, not viral-induced. High C and N will support maximal growth and unrestricted virus replication with no cellular lysis. Under low C growth conditions, the replication of PsV-S is favored coupled with high pH and autolysis.
Mise en évidence d'ADN extrachromosomique chez Rhizobium meliloti
Authors: Bechet M. , Guillaume J. B.
Published: April 2010

Seven effective (nitrogen-fixing) strains of Rhizobium meliloti have been studied. By sedimentation analysis of their alkaline lysates in alkaline sucrose gradients, a plasmid was found in four strains. In a strain (2011 str 3) which gave no result with this method, supercoiled DNA was detected by CsCl-dye buoyant density gradient centrifugation. That result was confirmed by analytical Cs2SO4–Ag+ density gradients, which showed a heterogeneity in the average base composition of the DNA extracted from three strains, including the 2011 str 3 strain. Two of those last strains seemed to contain an extrachromosomal DNA of very high molecular weight.
Nutritional characteristics of Megasphaera elsdenii
Authors: Forsberg C.W.
Published: April 2010

Megasphaera elsdenii B159 (formerly Peptostreptococcus elsdenii; Rogosa 1971) is able to grow in a chemically defined medium containing minerals, NH4+ as the sole nitrogen source, sulfate as the source of sulfur, acetate and glucose as the carbon and energy sources, and the vitamins biotin, pyridoxine, and calcium pantothenate. When lactate serves as the carbon source, with cysteine present as the reducing agent, acetate is not required. Valine and threonine appeared to be required although direct inoculation of unwashed cells into media lacking these amino acids permitted growth in their absence after an extended incubation period. Sulfur sources utilized included sulfate, sulfide, thiosulfate, cysteine, and glutathionine; methionine was utilized less readily. When glucose was autoclaved in the medium, the generation time of M. elsdenii was 170–200 min, but increased to more than 400 min when glucose was autoclaved separately and added to the cooled sterile medium. When fructose, which had been sterilized separately, was utilized as the carbon and energy source, the generation time was 200 min.
Investigations into the kinetics and stoichiometry of bacterial oxidation of covellite (CuS) using a polarographic oxygen probe
Authors: Rickard Pamela A. D. , Vanselow Donald G.
Published: April 2010

"Oxygraph" apparatus was used to measure quantitatively the kinetics of oxidation of synthetic covellite (CuS) in the presence and absence of Thiobacillus species. The expected stoichiometric relationship between oxygen consumed and cupric sulphate produced was verified by atomic absorption assays of cupric ion and sulphate ion. Thiobacillus cultures markedly increased the oxidation rate.The dependence of each oxygen-uptake rate on oxygen concentration was also measured. Sterile controls and some bacterial cultures showed first-order kinetics while other cultures showed zero-order kinetics.Addition of biological inhibitors to reacting slurries revealed that cultures showing first-order kinetics did not oxidize CuS itself but merely oxidized elemental sulphur formed by non-enzymic oxidation of CuS. Cultures showing zero-order kinetics oxidized CuS in a way that resulted in all oxygen reduction being enzymic. This mechanism possibly involves the cyclic oxidation and reduction of soluble iron.
Effect of three antagonists on the development of bacterial leaf streak of rice
Authors: Rao C. Seshagiri , Devadath S. , Dath A. Premalatha
Published: April 2010

Among 11 epiphytic microorganisms one species each of Pseudomonas, Erwinia, and Aspergillus were antagonistic to Xanthomonas translucens subsp. oryzicola. Symptoms of bacterial leaf streak did not develop when the antagonists were sprayed on rice leaves 24 h before inoculation. Although the symptoms developed when the antagonists were applied 24 h after inoculation, the number of lesions and their length was significantly reduced over control. When the mixture of each antagonist and the pathogen was applied, no symptoms developed with Pseudomonas and Aspergillus sp. However, the symptoms could develop with Erwinia sp. although the number and length of the lesions was reduced over control.
Intracellular cyclic adenosine 3′,5′-monophosphate levels and streptomycin production in cultures of Streptomyces griseus
Authors: Ragan C. M. , Vining L. C.
Published: April 2010

Changes in the amount of cyclic 3′,5′-adenosine monophosphate within the mycelium of Streptomyces griseus were measured as cultures progressed through trophophase and idiophase in a complex medium supporting growth and streptomycin synthesis. Concentrations were highest before the cultures entered stationary phase and had declined 90% by 5 h before the antibiotic was produced. This low concentration was maintained while the antibiotic accumulated during the idiophase. The results indicate that the onset of streptomycin synthesis is not directly mediated by an increase in intracellular cyclic 3′,5′-adenosine monophosphate concentration, and thus that antibiotic production in S. griseus is not controlled by catabolite repression.
Effect of glucosamine on virus production and antigen expression in avian sarcoma virus-transformed cells
Authors: Israel E. , Mandeville R. , Wainberg M. A.
Published: April 2010

Treatment by glucosamine of avian sarcoma virus-transformed chicken embryo fibroblast (CEF) cells completely inhibited the formation of progeny-transforming virus particles. Such cells, however, could continue to synthesize non-infectious physical particles containing both viral RNA and the enzyme RNA-dependent DNA polymerase if glucosamine exposure was performed in the presence of glucose. Glucosamine treatment was found to affect antigenic expression in transformed CEF as measured by an indirect immunofluorescence test. Inhibition to a far lesser extent was observed when a lymphocyte stimulation assay for the detection of cell-mediated immunity was used in this system.
Purine metabolism and differential inhibition of spore germination in Phytophthora infestans
Authors: Clark M. C. , Melanson D. L. , Page O. T.
Published: April 2010

An analysis of the effect of various purines and pyrimidines on the germination process in three different isolates of the late blight fungus, Phytophthora infestans, revealed increased rates of indirect germination in one isolate by adenine, hypoxanthine, and the riboside of dimethylaminopurine. This observation coupled with the capacity of sporangia of the race affected (1.2.3.4) for the uptake and interconversion of purines, as demonstrated by experiments with labelled purines under in vivo and in vitro conditions, pointed to hypoxanthine as a key intermediate in the purine metabolism directly associated with spore formation and development. This enhanced germination contrasted sharply with the almost complete arrest of indirect germination that occurred when sporangia were incubated with the purine analogue, benzimidazole, or with either of the respiratory inhibitors, sodium azide and 2,4-dinitrophenol.The pattern of differential inhibition exhibited by sporangia versus zoospores upon treatment with actinomycin D, 4-fluorouracil, or cycloheximide indicated that continued translation on preformed messenger RNA may be one essential requirement for the formation and release of zoospores, whereas their subsequent germination and development may depend upon renewed transcription as well.
Use of a single infusion bottle to culture and prepare potentially hazardous microorganisms for biochemical analysis
Authors: Weijman A. C. M.
Published: April 2010

A procedure is described to culture, harvest, kill, wash, freeze-dry, and store microorganisms for biochemical analysis. This method using a single infusion bottle is far less laborious than conventional procedures and reduces the risk of contamination.
Effects of amino acids on Thiobacillus acidophilus I. Growth studies with special reference to valine
Authors: Proteau Gérald , Silver Marvin
Published: April 2010

The heterotrophic growth of Thiobacillus acidophilus was inhibited by branched-chain amino acids; valine, isoleucine, and leucine. The inhibition by valine and leucine were partially reversed by isoleucine, and the inhibition by isoleucine was partially reversed by valine. Inhibitions by methionine or threonine were partially reversed when both amino acids were present in the growth medium. Inhibition by tyrosine was increased by phenylalanine or tryptophan. Cystine completely inhibited growth. Other amino acids tested produced little or no inhibition.Acetohydroxy acid synthetase (AHAS) activity was demonstrated in crude extracts of T. acidophilus. In crude extracts the optimum pH was 8.5 with a shift to 9.0 in the presence of valine. Valine was the only branched-chain amino acid which inhibited the AHAS activity. The presence of only one peak of AHAS activity upon centrifugation in linear glycerol density gradients demonstrated that the AHAS activity sediments as one component.
The induction of giant ring traps and regulation of conidiogenesis in the predacious fungus Dactylella brochopaga
Authors: Turnbull J. R. , Zachariah K.
Published: April 2010

The nematophagous fungus Dactylella brochopaga was grown and supplied with prey under different conditions of light and atmospheric stagnation. Poor ventilation induced the formation of functional giant traps, hitherto unreported. Darkness inhibited sporulation. The adaptive significance of these changes is discussed.
Chromosome age and segregation during sporulation of Bacillus megaterium
Authors: Hitchins Anthony D.
Published: April 2010

The effect of chromosome age on segregation during sporulation was investigated. Vegetative cells of Bacillus megaterium were labeled with [Me-3H]thymine and then were grown at 30 °C in nonradioactive medium for various times before being allowed to sporulate. The ratio of the amount of label in sporal DNA to that in sporangial DNA, obtained after minor correction for the sporulation frequency, remained essentially constant as the postlabeling growth period was increased from one to seven generations. The spores were preferentially located at the older poles of sporangia, i.e. the poles formed by divisions occurring prior to those forming the sporangia. Therefore, it seems that old (labeled) chromosomes segregate randomly with respect to both the morphological and genealogical polarities of sporangia. Examination of total cell lysates by dye–buoyant density gradient centrifugation revealed the presence of covalently closed circular DNA from cells grown at 37 °C, but none was obtained from cells grown at 30 °C. Thus, possible interference by large amounts of extrachromosomal DNA in the determination of the chromosomal segregation pattern is unlikely.
Isolation of tuberculin peptides from tuberculin purified protein derivative (PPD)
Authors: Gupta K. C. , Landi S.
Published: April 2010

Tuberculin purified protein derivative (PPD) obtained from the filtrate of Mycobacterium tuberculosis was hydrolysed with proteinase, trypsin, or chymotrypsin. Each hydrolysate consisted of a tuberculin peptides mixture (TPM). From each TPM 16 fractions were obtained by ion-exchange chromatography on Dowex 50W-X8 but only one fraction was isolated from each of the 16 fractions which showed tuberculin activity in guinea pigs sensitized with M. bovis (BCG) or M. tuberculosis. This fraction was designated "purified tuberculin peptide" (PTP).The PTP fraction from the proteinase hydrolysate (PTP-proteinase) was rechromatographed on Dowex 1-X2 and two tuberculin peptide fractions having molecular weights of 3200 and 12 000 were isolated. The potency of these two fractions was assessed in guinea pigs sensitized with M. bovis (BCG) and with M. tuberculosis and they were approximately 4 to 7 times more potent than either the international standard for PPD (PPD-S) or Connaught PPD in guinea pigs sensitized with BCG and of at least equal potency to either PPD-S or Connaught PPD in guinea pigs sensitized with M. tuberculosis. Connaught tuberculin PPD cross-reacted in guinea pigs sensitized with either M. kansasii, M. scrofulaceum, M. intracellulare, or M. avium whereas very little if any cross-reactivity was elicited by these two fractions. This lack of response indicates that either fraction could be used as an aid to differentiate between sensitization due to M. tuberculosis or M. bovis and sensitization attributed to other mycobacteria.
A method for the detection and analysis of growth patterns of microorganisms in soil
Authors: Polonenko D. R. , Pike D. J. , Mayfield C. I.
Published: April 2010

A fluorescence-staining technique using the magnesium salt of 8-anilino-1-naphthalene sulfonic acid is described and used to follow the changes in the distribution patterns of microorganisms in soils. A statistical procedure was used to determine the occurrence of significant differences in clumping of bacteria (i.e., production of colonies) in different regions of artificial soil-aggregate systems treated with nutrient solutions and also with a herbicide, Linuron. The response of soil microorganisms to glucose amendment was most marked in the aerobic, outer zone of aggregates. Linuron inhibited colony formation in aggregates treated with the herbicide. The method allows continued observations to be made on the same soil sample at intervals during incubation and so can be used to determine growth rates, inhibitory effects of chemicals, distribution patterns in soils, effects of added nutrients, and other effects where growth in situ is important.
Use of fluorochromes for direct observation of microorganisms associated with wheat roots
Authors: Vuurde J. W. L. van , Elenbaas P. F. M.
Published: April 2010

The use of several fluorochromes and staining methods was tried out for observation of microorganisms on the surface of wheat roots sampled from soil. Good contrast between fluorescence of microorganisms and fluorescence of root and soil structures was obtained after successive staining of roots with coriphosphine (1:2000, 15 min), congo red (1:10000, 10 min), and acridine-orange (1:10000, 2 min).
A new technique for the preparation of permanent reference cultures of fungi
Authors: Hofherr Louise
Published: April 2010

Fungal cultures were grown by a new microslide method and by the traditional slide-culture method. Sporulation results were similar by both methods. The microslide method has the advantages of increased safety to the user and ease of storage.
Thermal analysis of the spores of Bacillus cereus with special reference to heat activation
Authors: Maeda Yoshimi , Kagami Ikuzo , Koga Shozo
Published: April 2010

The heat activation of bacterial spores was studied by means of differential thermal analysis in the temperature range 30–110 °C using the spores of Bacillus cereus. The thermogram showed three endothermic peaks at 56, 95, and 103 °C with one exothermic peak at 105 °C during the heating process. The spore coat separated from the native spores also showed a peak at 56 °C on its heating thermogram. The peak at 56 °C was reversible for both native spores and the spore coat. It was suggested that this peak at 56 °C might be related to the heat-activation process that takes place in the spore-coat region. It seems that the peak is due to the denaturation or the structural change of the spore-coat protein that might facilitate either the permeation of germination stimulators or the release of some germination inhibitor into or out of the spores.
5-Fluoroorotate-resistant mutants of Salmonella typhimurium
Authors: Zak Victor L. , Kelln Rod A.
Published: April 2010

Spontaneously occurring mutants of Salmonella typhimurium resistant to 5-fluoroorotate (5-FOA) were isolated. One class of mutant showed marked derepression of pyrimidine biosynthetic enzymes and had the unusual property of being unable to grow on nutrient agar. However, when the osmotic strength of nutrient agar was increased, the mutants were able to grow. The genetic basis for the osmotic fragility and elevated pyr enzyme synthesis was the result of mutations affecting pyrH, encoding the enzyme uridine 5′-monophosphate kinase.
The effect of pH and amino acids on conidiation and pigment production of Monascus major ATCC 16362 and Monascus rubiginosus ATCC 16367 in submerged shaken culture
Authors: Carels Mariette , Shepherd David
Published: April 2010

Monascus major ATCC 16362 and Monascus rubiginosus ATCC 16367 were cultivated aerobically on media containing nitrate or ammonium as nitrogen source to which the following modifications were made: (1) pH adjusted to 2.5 before sterilization; (2) addition of yeast extract; (3) addition of amino acids in identical proportions and concentrations to those found in yeast extract; (4) adjustment of pH to 2.5 after addition of amino acids.The addition of amino acids in the form of yeast extract increased mycelium formation and reduced conidiation and pigment production. The addition of an amino acid mixture did not increase mycelium formation to the same extent as yeast extract but increased the number of conidia, while pigment production was reduced, especially when nitrate was the nitrogen source. As the amino acids are taken up after conidial formation has started, it would appear that it is not the amino acids themselves which are directly responsible for the induction of conidiation. The addition of amino acids inhibits nitrate and ammonium uptake suggesting the need for an early intracellular nitrogen limitation to induce conidiation. Lowering the pH inhibits the formation of conidia and increases pigment production; also the effect of amino acid addition is totally annulled.The pH of the medium is all important in regulating the formation of conidia and pigment production. The possible effects of the pH on the uptake of certain medium components is discussed, as well as their possible control of certain metabolic pathways which ultimately determines the availability of intermediates for conidiation and pigment production.
The effect of temperature on phenol degradation in wastewater
Authors: Vela G. R. , Ralston James R.
Published: April 2010

Data are presented which show that the microbiological degradation of phenol in industrial wastewater is affected by temperature in an unexpected manner. The rate of degradation is unaffected by temperature changes in the range from 24 to 10 °C but falls off rapidly at temperatures below 10 °C. In the interval from 10 to 2 °C the rate of degradation is a function of temperature and is proportional to the rate of growth of the bacteria studied. By contrast, the increase in rate of phenol degradation is much greater than the increase in growth rate as the temperature increases from 10 to 24 °C. Field and laboratory studies show that increased efficiency of phenol degradation in wastewater is due to increase in temperature rather than to shifts in microbial populations.
Structure of the D-glucans produced by Neisseria perflava
Authors: MacKenzie C. R. , Perry M. B. , McDonald I. J. , Johnson K. G.
Published: April 2010

A chemical and enzymic study of the cellular glucan of Neisseria perflava and of the glucan produced from sucrose by a cell-free extract of N. perflava showed from optical rotation, 13C nuclear magnetic resonance, methylation analysis, and α- and β-amylase hydrolysis studies that the glucans had glycogen-like structures. These structures were composed of chains of 1-4-α-D-glucopyranosyl units with branch points of 4-O- and 6-O- disubstituted D-glucopyranose units. While the backbone structures of the two glucans were similar, the release of maltose by the action of β-amylase indicated that the 1–4 linked nonreducing side chains of the cell-free enzymically synthesized glucan were longer (~seven units) than those present in the cellular glucan (~two to three units), a result in agreement with methylation analyses.
Construction of an Escherichia coli strain which excretes abnormally large amounts of adenosine 3′,5′-cyclic monophosphate
Authors: Fraser Ann D. E. , Yamazaki Hiroshi
Published: April 2010

It has previously been shown that an Escherichia coli CRP− strain 5333 accumulates abnormally large amounts of adenosine 3′,5′-cyclic monophosphate (cAMP). Using P1 transduction, the CRP− character was transferred to E. coli Crookes strain which is deficient for cAMP phosphodiesterase (CPD−). The resulting strain HY22 (CRP−, CPD−) accumulates greater amounts of cAMP both intracellularly and extracellularly than does 5333. In glucose minimal medium, an HY22 cell accumulates 100 times more cAMP intracellularly and excretes cAMP 150 times faster than does a wild-type E. coli cell.
Production de vitamine B12 par une algue bleue
Authors: Grieco E. , Desrochers R.
Published: April 2010

In this study, we have been able to demonstrate the production and liberation of vitamin B12 (up to 16.5 pg/ml after 31 days of growth) by a blue green alga, Anabaena flos-aquae, in non-axenic and axenic cultures. This finding has a relevant ecological significance since it shows that, like bacteria, blue green algae may play a role as producers of vitamin B12.
Endotoxin in germfree, gnotobiotic, or conventional-flora Sprague–Dawley rats
Authors: McLeod Joy C. , Balish Edward
Published: April 2010

The Limulus assay for bacterial endotoxin was performed on serum and (or) plasma from animals monoassociated with Clostridium species. Staphylococcus aureus, Escherichia coli, Proteus mirabilis, Enterobacter agglomerans, Bacteroides fragilis, Klebsiella pneumoniae, or Candida albicans.Plasma from animals monoassociated with the gram-negative bacteria or C. albicans consistently showed a positive Limulus test while conventional-flora controls, germfree rats, and gnotobiotic animals monoassociated with gram-positive bacteria or E. agglomerans were negative.Germfree and conventional rats were injected (intraperitoneal (i.p.)) with Salmonella typhosa lipopolysaccharide (LPS). Although no endotoxin was detectable in either group prior to the injection, by 1 h post injection endotoxin was in the plasma of all groups. The germfree rats appeared to clear the LPS quicker than their conventional-flora counterparts.Generally, LPS-injected rats (conventional and germfree) showed clumping and decreased number of platelets, a decrease in their lymphocyte counts, and increased polymorphonuclear leukocyte (PMN) counts.
Isolation of auxotrophs of Bacteroides fragilis
Authors: Tassell Roger L. Van , Wilkins Tracy D.
Published: April 2010

Techniques employing ethane methanesulfonate and modified penicillin enrichment were developed whereby auxotrophs of Bacteroides fragilis could be readily isolated. Several auxo trophic phenotypes are described.
Studies of the microaerophilic nature of Campylobacter fetus subsp. jejuni. I. Physiological aspects of enhanced aerotolerance
Authors: Hoffman Paul S. , Krieg Noel R. , Smibert Robert M.
Published: April 2010

The aerotolerance of the microaerophilic bacterium Campylobacter fetus subsp. jejuni strain H840 (ATCC 29428) can be enhanced by addition of a combination of ferrous sulfate, sodium bisulfite, and sodium pyruvate (FBP), or of dihydroxyphenyl compounds such as nor-epinephrine (NE), to Brucella broth. Transport of 55Fe3+ was increased by NE, suggesting that ordinary rates of transport, while adequate for growth at 6% O2, might not permit growth at 21% O2. Growth with FBP at 21% O2 did not appreciably affect levels of cytochromes or of various tricarboxylic acid cycle enzyme activities. Activities of certain iron-dependent enzymes (succinate dehydrogenase and aconitate hydratase), and also respiration rates of whole cells, were lower in cells grown at 21% O2 in Brucella broth compared to 6% O2, but FBP did not cause an increase in these activities or rates. FBP caused a decrease in catalase and peroxidase activities. Total superoxide dismutase (SOD) activity increased when cells were grown at 21% O2 with FBP. When grown without FBP, however, the organism possessed SOD activity as high as that in Escherichia coli, and a variant strain of H840 possessed nearly double this activity but was no more aerotolerant than the parent strain. A very oxygen-sensitive strain of C. fetus subsp. intestinalis also possessed high SOD activity. Consequently, total SOD activity in C. fetus does not appear to account for lack of aerotolerance. No evidence that FBPcauses any physiological change in C. fetus that could satisfactorily account for enhancement of aerotolerance could be obtained. It is possible that FBP or NE might not affect some physiological process in the organisms but might instead act on the culture medium.
Effect of non-fat dry milk on recovery of staphylococcal thermonuclease from foods
Authors: Park C. E. , Derea H. B. El , Rayman M. K.
Published: April 2010

Modification of the method of Tatini et al. (1976) by addition of non-fat dry milk (NFDM) to food samples and subsequent acid precipitation at pH 3.8 enhanced the recovery of staphylococcal thermonuclease (TNase) from most of 37 foods tested. The modified TNase assay method allowed detection of 10 ng (0.002 units) of the enzyme per gram of each of the following foods: ground beef, boiled egg products, whey powder, fruit-containing yogurt, dressings and spreads, potato and egg salads, and pastas, all of which gave false-negative results without NFDM.
Ultrastructural studies on the cell walls in Fusarium sulphureum
Authors: Schneider Edward F. , Wardrop Alan B.
Published: April 2010

The cell walls of Fusarium sulphureum have a microfibrillar component that is randomly arranged. X-ray-diffraction diagrams of the microfibrils are consistent with a high degree of crystallinity and show that they are chitin. The chitin microfibrils of the peripheral walls envelop the hyphal apex and extend across the septae. During the first 8 h in culture, the conversion of conidial cells to chlamydospores is evidenced by a swelling of the cells and the original microfibrils remain randomly arranged. Within 24 h new wall material is deposited as the cells expand and the wall thickens. The new microfibrils are indistinguishable from those of the original conidial cells.After 3 days in culture, the chlamydospores are fully developed and have the characteristic thick wall which is a continuous layer of randomly arranged microfibrils. Chlamydospores maintained in a conversion medium for 8 days have microfibrils identical with those in 3-day-old cultures; thus a further change in the microfibril orientation did not occur during that period.Alkaline hydrolysis of the walls removes most of the electron-dense staining constituents from the inner wall layer and leaves the outer wall layer intact. This treatment also reveals some of the wall microfibrils. An additional treatment of the walls with HAc/H2O2 completely removes the wall components that react positively to heavy metal stains. The results are discussed in relation to the structure of other fungal cell walls.
Temperature-sensitive mutants of bacteriophage SH-133 specific for the hydrogen bacterium Pseudomonas facilis: isolation, complementation, and partial characterization
Authors: Battreall Christine M. , Friedrichs William E. , Reed Jeffrey P. , Aron Gary M.
Published: April 2010

Seventeen temperature-sensitive mutants of bacteriophage SH-133 have been isolated following mutagenesis with UV-light, nitrosoguanidine, and ethyl methanesulfonate. The mutants were classified into 15 complementation groups according to their ability to complement each other at 32 °C, the nonpermissive temperature. Each mutant was studied with regard to the relationship between its ability to multiply in heterotrophically (H-) and autotrophically (A-) grown Pseudomonas facilis cells. At 27 °C, the permissive temperature, the plaque-forming ability of the 17 mutants and wild-type phage was reduced 10-fold in A-grown cells. At 32 °C, mutants belonging to 10 groups exhibited identical levels of multiplicity-dependent leak under both modes of growth. However, the infection of A-grown cells by mutants belonging to the remaining five groups resulted in as much as 500-fold inhibition of multiplicity-dependent leak when contrasted with the infection of cells grown heterotrophically. These observations indicate that the expression of five SH-133 phage cistrons is defective when multiplication proceeds under autotrophic metabolism. Seven mutants were found to differ from the wild-type phage with regard to thermal stability at 56 °C which suggests that they possess altered structural proteins. Four of the seven thermosensitive mutants exhibited reduced levels of multiplicity-dependent leak in A-grown cells. The data suggest that the reduction in plaque-forming ability of SH-133 in A-grown cells is caused by a defect in the expression of specific phage structural components.
Effect of serum–antigen incubation times on the expression of non-specific inhibitors of rubella hemagglutination
Authors: Campbell James B.
Published: April 2010

Under certain conditions, serum very low-density lipoproteins (VLDL) and high-density lipoproteins (HDL) can inhibit rubella hemagglutination. The level of this non-specific hemagglutination-inhibition (HI) activity increases as the incubation period between serum and antigen is increased. Treatment of serum with heparin–MnCl2 does not precipitate HDL, and may not effect complete removal of all VLDL. This treatment method, therefore, should be considered a source of false-positive reactions, especially when extended serum–antigen incubation periods are used to enhance HI activity and to detect low levels of IgM.
Enumeration of stressed cells of Escherichia coli
Authors: Egan Aubrey F.
Published: April 2010

Cells of Escherichia coli K-12 were stressed by heating at 48 °C or by acid treatment at pH 4.2 for periods up to 1 h. The addition of catalase to the selective medium increased the count of heat-stressed cells by 2.3-fold and acid-stressed cells by 4.8-fold. However, these values represented only a small percentage (3% for heat-stressed and 6% for acid-stressed cells respectively) of the population of injured but still viable cells. The addition of mannitol to the selective medium used to count acid-stressed cells did not increase the count. Whilst the presence of H2O2, in media may cause significant errors in the estimation of E. coli in certain situations these errors are unlikely to be significant in physiological studies of populations of cells injured by stress.
Penetration into caterpillar cells of virus-like particles injected during oviposition by parasitoid ichneumonid wasps
Authors: Stoltz Donald B. , Vinson S. Bradleigh
Published: April 2010

Particles originating from the ovarial calyx epithelium of two different species of ichneumonid wasp are injected into host caterpillars during oviposition. At [Formula: see text] post oviposition, many calyx fluid particles are either associated with or have penetrated through the basement membranes surrounding various tissues. Shortly thereafter, apparently intact particle nucleocapsids are observed in both the cytoplasm and nucleus of host cells. An unusual tubular protrusion of the viral envelope appears to be involved in either or both of penetration of basement membranes and entry of nucleocapsids into host cells.
Activation of serum prophenoloxidase in arthropod immunity. The specificity of cell wall glucan activation and activation by purified fungal glycoproteins of crayfish phenoloxidase
Authors: Söderhäll Kenneth , Unestam Torgny
Published: April 2010

This study shows that the activation of crayfish serum prophenoloxidase by carbohydrates was specific for β-1,3-glucans. Fractionation of the β-1,3-glucan laminaran into laminaran M and laminaran G showed that both activated the proenzyme, but the G-chain had somewhat higher affinity for the proenzyme. Methylation analysis of these two fractions revealed that there were no 1,6-linkages present. Laminaripentaose, a linear pentasaccharide composed of (1 → 3)-linked β-D-glucopyranosyl residues was also active but had a lower affinity for the proenzyme than laminaran G. Laminaran completely inhibited the activation of prophenoloxidase by the pentaose. In the concentrations tested, laminaran was not inhibitory to the phenoloxidase activity.Purified extracellular glycoproteins of the parasitic fungus Aphanomyces astaci also strongly activated crayfish serum prophenoloxidase. Only high molecular weight glycoproteins were effective. Exo-β-1,3-glucanase treatment decreased the activating capacity, suggesting that at least part of the glycoproteins consisted of β-1,3-glucans. The significance of these results in the defence against parasitic fungi in crayfish is discussed.
A tentative direct microscopic method for counting living marine bacteria
Authors: Kogure Kazuhiro , Simidu Ushio , Taga Nobuo
Published: April 2010

Yeast extract (0.025%) and nalidixic acid (0.002%) were added to seawater samples and the samples were incubated for 6 h at 20 °C in the dark. Under these conditions, bacterial cells did not divide but grew to form elongated cells that are easily recognized by a direct microscopic method and epifluorescent microscopic technique. The number of cells thus obtained is proposed as a direct count of viable bacterial cells (DVC). With open ocean samples, DVC was higher than 'viable' plate counts by up to three orders of magnitude and lower than the direct counts by about one order.
A propos de l'activité antibactérienne de la zéaralénone
Authors: Boutibonnes P.
Published: April 2010

Zearalenone, a mycotoxin secreted by Fusarium sp. and Gibberella zeae, shows a narrow range of antibacterial activity limited to some Gram-positive aerobic spore-forming bacteria. In Bacillus thuringiensis (Berliner), a highly sensitive species, this activity is characterized by a decrease of cellular division and induction of atypical cells. These effects resemble those obtained with two other mycotoxins which possess a lactone structure: aflatoxin B1 and patulin.
Optimization on the selection of auxotrophic mutants in Candida utilis by snail enzyme treatment
Authors: Delgado J. M. , Herrera L. S. , Pérez C. , López R.
Published: April 2010

The determination of the best conditions for the application of the snail enzyme digestion method in the enrichment of auxotrophic mutants in Candida utilis was carried out following Box and Wilson's mathematical method. The selection procedure proposed was tested in the enrichment of auxotrophic mutants from a mutagenized culture of a wild-type strain. Mutant frequency was increased 46-fold by treatment with snail enzyme. The method also proved useful in the selection of additional auxotrophic mutations from single auxotrophs.
Auxanographic grouping and typing of Neisseria gonorrhoeae
Authors: Hendry A. T. , Stewart I. O.
Published: April 2010

Nearly 96% of 1297 Neisseria gonorrhoeae isolates in Hamilton were assigned to six major auxanographic groups (non-requiring or NR, Pro−, Orn−, Pro−Cit−Ura−, Orn−Ura−Hyx−, Cit−Ura−Hyx−) as established by requirements for none, or any one or more of proline, uracil, hypoxanthine, citrulline (Cit−), or citrulline replaceable by ornithine (Orn−) on chemically defined medium modified from Catlin (1973). Seven other groups, and strains not growing, accounted for 4.2%. The most common groups were Orn−Ura−Hyx− (25.6%) and Pro−Cit−Ura− (31.8%). This latter group has not been previously described.These "Pro Cit/Orn Ura Hyx" criteria were among the most unequivocal to interpret; with rare exceptions for proline, a requirement was shown by absence of growth at any time in the zones of inoculation from a replicator. For some strains, some of the possible additional requirements (leucine, valine, isoleucine, glutamine, threonine, serine, histidine, etc.) could be less readily ascertained, because an occasional manifestation was to reduce the amount of growth, or to slow down the rate of growth, compared to complete medium.The first four of the six groups were the least fastidious, in that few strains had any additional requirements.About 2% of strains were inhibited by 0.25 mM phenylalanine.
Outgrowth and sporulation studies on Clostridium botulinum type E: influence of isoleucine
Authors: Hawirko R. Z. , Naccarato C. A. , Lee R. P. W. , Maeba P. Y.
Published: April 2010

A defined medium (CDM) is described which supported growth and sporulation of type E strains of Clostridium botulinum, but not sporulation of other serotypes of C. botulinum or C. sporogenes. As compared to growth in complex medium, spore outgrowth was delayed and both the growth rate and the cell yield was reduced. However, efficiency of sporulation of the type E MSp+ strain in a chemically defined medium (CDM) was the same as that in complex medium and, in fact, sporulation was nearly synchronous and completed within 3 h of the first appearance of phase-bright endospores, compared with completion in 9 h in TPGY. Growth studies with CDM, from which single amino acids were omitted, showed that isoleucine was essential for outgrowth of heat-activated spores of the MSp+ strain, whereas valine was required for that of the Ts-25 mutant. Radioactive isoleucine was incorporated by germinating MSp+ spores at an earlier stage and at a more rapid rate than labelled methionine or mixed amino acids. Uptake studies showed that isoleucine accumulated in a prominent acid-soluble pool during outgrowth, a period when its incorporation into protein was not evident. The results suggest that the isoleucine may be required for a purpose other than protein synthesis during outgrowth.
Evidence for chemotaxis during sexual development in Dictyostelium discoideum
Authors: O'Day Danton H. , Durston Antony J.
Published: April 2010

Amoebae in mated cultures of Dictyostelium discoideum show oriented movement towards young aggregates, suggesting that chemotaxis is involved in macrocyst development. Amoebae also show directional movement towards midendocyte stages, indicating that as the macrocyst develops it continues to be a source of chemoattractant. These data are discussed in terms of our current knowledge about mating in the cellular slime moulds.
Second-step concentration of viruses in drinking and surface waters using polyethylene glycol hydroextraction
Authors: Ramia Sami , Sattar Syed A.
Published: April 2010

In our laboratory, virus adsorbed to talc–Celite layers is eluted with 100 mL of 10% fetal calf serum (FCS) in normal saline (pH 9.0). A further 10-fold reduction in the volume of the eluate was necessary before its inoculation into cell cultures.A 100-mL volume of an experimentally contaminated sample was placed in a dialysis sac and hydroextracted overnight (4 °C) with polyethylene glycol (PEG) 6000. The viscous material remaining in the sac was resuspended in 10 mL of Earle's balanced salt solution. After membrane filtration (0.2 μm), the concentrate was plaque assayed in BS-C-1 cells. Using this technique, recoveries of five laboratory-adapted enteric viruses (polio 1, echo 6, coxsackie B5, coxsackie A9, and reo 3) and four freshly isolated enteric virus strains (polio 1, echo 1, coxsackie B3, and reo) ranged from 87 to 97%. In comparative tests, PEG hydroextraction was simpler and superior to organic flocculation.
Effect of glycerol on viability and other properties of starved Mycobacterium fortuitum
Authors: Majtán V. , Drobnica L.
Published: April 2010

Cells of Mycobacterium fortuitum kept in 0.85% saline solution containing 0.1% Tween 80 (without glycerol) survive for a long time. In glycerol-enriched medium, they continue to lose their viability at a high rate; after 71 days of exposure the percentage of survival as indicated by colony formation and respiratory and dehydrogenase activities is lower than 1%. Surviving cells starved in medium without glycerol revealed unchanged sensitivity to streptomycin, p-amino-salicylic acid, and isoniazid.
Transfer and integration of chromosomal genes from Pseudomonas glycinea into Pseudomonas aeruginosa
Authors: Leary John V.
Published: April 2010

The plasmids FP2and R68.45 were shown to function as chromosome-mobilizing plasmids in a series of interspecific crosses between the phytopathogen Pseudomonas glycinea and the human pathogen Pseudomonas aeruginosa. At least four of seven loci tested were transferred from P. glycinea donors to P. aeruginosa auxotrophic recipients. Transductional analysis indicates that a leu+ locus of the P. glycinea chromosome transferred is stably integrated into the P. aeruginosa chromosome.
Stimulation of monocyte precursors in vivo by an extract from Listeria monocytogenes
Authors: Shum D. T. , Galsworthy S. B.
Published: April 2010

A water-soluble monocytosis-producing activity (MPA) extracted from Listeria monocytogenes was found to stimulate proliferation of promonocytes in vivo. Mice were pulse-labelled for 2 h with tritiated thymidine ([3H]TdR) at various times after intraperitoneal injection of MPA. Autoradiography of bone marrow cells revealed an increased labelling index of promonocytes of MPA-treated mice which was maximum 8 h after the MPA injection. Mice labelled with [3H]TdR 8 h after MPA injection developed a monocytosis at the expected time (peak at 48 h) and the blood monocytes were found to be highly labelled. Both the generation time of monocyte precursors and the halftime of blood monocytes were found to be shorter than the corresponding values in control mice.