bluuebunny/crossref_metadata_2025 huggingface dataset:
A phage-like bacteriocin of Rhizobium trifolii
Authors: Schwinghamer E. A. , Pankhurst C. E. , Whitfeld P. R.
Published: February 2010

An inducible bacteriocin produced by a strain of Rhizobium trifolii was partially purified by ammonium sulfate precipitation and differential centrifugation. Examination of fractions of this material banded in sucrose gradients showed a close correlation between bacteriocin activity and presence of phage-like particles observed by electron microscopy. The particles have a head diameter of about 50 nm and have short tails. Buoyant density of intact particles in cesium chloride was 1.46 g/cm3, as compared with 1.49 g/cm3 for a reference rhizobiophage. The apparent nucleoprotein nature of the bacteriocin was confirmed by the ultraviolet absorption spectrum of CsCl-banded material. Double-stranded DNA of density 1.720 g/cm3 (compared with 1.716 g/cm3 for DNA of the phage) was identified in bacteriocin fractions obtained from CsCl density equilibrium gradients. This density was identical with that of DNA from both induced and noninduced bacterial cells of the producing strain. These characteristics and the inability to reproduce in sensitive bacteria identify the bactericidal agent as a large bacteriocin of the defective phage type. Some apparent differences between this bacteriocin and other, partly characterized bacteriocins of R. trifolii are discussed.
Rôle des acides aminés soufrés dans la croissance de Corynebacterium sepedonicum (Spieck. et Kott.) Skapt. et Burkh.
Authors: Paquin Roger , Boucher Yvan , Lachance Robert A.
Published: February 2010

Corynebacterium sepedonicum requires organic sulfur for its growth. In potato host tissue, the normal source of sulfur for the bacterium is methionine. The l isomer is more readily metabolized than the d isomer or the dl racemic mixture, but four derivatives, methionine sulfoxide, DL-methionine-CH3-sulfonium Cl, acetyl- and alanyl-methionine are more efficiently metabolized than any of the methionine isomers. Homocysteine and cystathionine, intermediates in methionine metabolism, are rapidly metabolized in the presence of trace amounts of methionine. Another intermediate, S-adenosylmethionine, has no effect on the bacterial growth. Ethionine and α-methylmethionine are not metabolized by C. sepedonicum and cystathionine or homocysteine cannot overcome the inhibitory effect of α-methylmethionine on growth of the organism.
A comparison of the electrophoretic properties of the ATP-sulfurylases, APS-reductases, and sulfite reductases from cultures of dissimilatory sulfate-reducing bacteria
Authors: Skyring G. W. , Trudinger P. A.
Published: February 2010

ATP-sulfurylases, APS-reductases, and sulfite reductases (SO3−2 → S−2) have been detected by gel disc electrophoresis in 13 cultures of dissimilatory sulfate-reducing bacteria and their electrophoretic properties have been compared. With respect to these three enzymes only, the results were indicative of some interspecies and intergenus homologies. In the Desulfovibrio strains (except Desulfovibrio desulfuricans 8301 which does not contain desulfoviridin), the major sulfite reductase was electrophoretically coincident with desulfoviridin and, in the Desulfotomaculum strains, with a brown protein. Some distinct patterns of electrophoretically distinguishable forms of APS-reductase were found. Considerable electrophoretic variation was found among the ATP-sulfurylases.
Surface structure of the conidium and conidiophore of Stemphylium botryosum
Authors: Corlett Michael
Published: February 2010

Observations with the scanning electron microscope reveal tuberculate prominences up to 0.75 to 1.0 μ high and 0.5 μ wide on the suface of the conidium. The prominences are 1.0 to 1.5 μ apart and in the mature conidia have flattened cap-like tops. The swollen tips of the conidiophores are finely warted.
Classification of some dermatophytes by pyrolysis–gas–liquid chromatography
Authors: Carmichael J. W. , Sekhon Awatar S. , Sigler Lynne
Published: February 2010

Samples from dried colonies of 21 strains of Nannizzia and Arthroderma were analyzed by pyrolysis–gas–liquid chromatography. Characteristic peak patterns produced by all the strains were used as markers to correct random drift in retention time so that corresponding peaks in different pyrograms could be homologized. Variation in sample size was compensated for by comparing peaks on each pyrogram with a particular major component and scoring them simply as 0 (absent), 1 (small), or 2 (large). Proximities were calculated and analyzed for clusters by the TAXMAP procedure. The analysis always grouped replicate samples together in the same cluster. Opposite mating types of the same species were sometimes placed in the same cluster and sometimes in separate clusters. The (+) mating type of Arthroderma benhamiae was placed in a cluster with both mating types of Nannizzia gypsea and N. obtusa, while the (−) mating type replicates of A. benhamiae were placed in a cluster by themselves. Finding a greater difference between pyrograms of different mating types of one species than between pyrograms of different species was unexpected and requires further investigation.
The mechanism of a host-dependent abortive bacteriophage infection in Caulobacter
Authors: Jollick J. D. , Gerencser V. F.
Published: February 2010

Several Caulobacter phages inhibit or kill host bacteria without phage production. Host-range studies showed that many of the Caulobacter strains that were sensitive to a particular phage were not productive hosts for that phage. Phage adsorbed to both productive and non-productive sensitive hosts but not to non-sensitive controls, nor to host cells treated with NaCN, or cells killed by ultraviolet (UV), heat, formaldehyde, or desiccation. Lysis from without could not be demonstrated. Ultraviolet-inactivated phage showed the same inhibitory effect on the non-productive hosts as did viable phage; however, purified tails of phage ø6 did not exhibit the capacity to inhibit the sensitive hosts. The UV adsorbance of the suspending medium of cell–phage mixtures increased with time in the case of the non-productive strain but not the productive strain. This increase indicates that leakage of intracellular material into the medium occurred as a result of phage infection of the non-productive strain but not the productive strain.
ICMSF methods studies. I. Comparison of analytical schemes for detection of Salmonella in dried foods
Authors: Silliker J. H. , Gabis D. A.
Published: February 2010

Twenty-six low-moisture food samples naturally contaminated with salmonellae were analyzed to compare the efficiency of sixty 25-g, fifteen 100-g, and three 500-g subsamples in recovery of salmonellae. In addition, the efficacy of wet compositing in recovery of salmonellae was studied by pooling in groups of five, the pre-enrichment broths from the 25-g and 100-g subsamples. Eighteen of the samples were positive by all sampling procedures. Four of the samples were negative when sixty 25-g subsamples were analyzed, four were negative by the fifteen 100-g sub-samples, and two were negative by the three 500-g subsamples. Wet-compositing results indicate the method is as sensitive in detecting salmonellae as the analysis of individual subsamples. The overall results indicate samonellae may be detected with equal facility by any of the sampling and analytical methods tested.
Modification of the sporulation cycle in Penicillium digitatum (Sacc.)
Authors: Zeidler G. , Margalith P.
Published: February 2010

The effect of amino acids on the sporulation time of Penicillium digitatum was studied. Glutamic and aspartic acids as sole nitrogen sources accelerated sporulation by 10–12 h. In the presence of a number of amino acids "microcycle sporulation" could also be observed. Tryptophane increased significantly the length of the conidial chain.
Effect of uridine on the incorporation of thymine and thymidine in Escherichia coli
Authors: Behki R. M. , Lesley S. M.
Published: February 2010

Uridine inhibits the incorporation of thymine in Escherichia coli 15T− cells but the duration of this inhibition is dependent upon the initial concentration of uridine and its rate of degradation. Uridine is rapidly degraded to uracil and the completion of this degradation coincides with the release of the inhibitory effect. However, uridine, by preventing the phosphorolysis of thymidine, allows the continued incorporation of the intact molecule at the initial high rate for as long as the concentration of undegraded uridine remains above a certain level. In resuspended 15T− cells, this rate is the same, irrespective of the presence or absence of uridine. The results presented here provide a simple method of controlling DNA synthesis, as represented by thymine incorporation, without the addition of inhibitors or other manipulations of the cell cultures.
Ultrastructure and lipid changes in Pyrenochaeta terrestris during aging
Authors: Gunasekaran M. , Hess W. M. , Weber D. J.
Published: February 2010

Pyrenochaeta terrestris, the onion pink root fungus, was grown on a reciprocal shaker in a synthetic medium which contained cellulose as the only carbon source. The mycelium was processed for lipid analysis and ultrastructural investigations after 8, 16, 24, and 32-day growth intervals.Hyphal cells contained membrane complexes. An electron-dense substance was present in large quantities on hyphal cell walls until after the 24-day period. As the cultures aged, organelles in some hyphal cells disintegrated and viable hyphal cells grew inside senescent cells in some cases. It was not possible to correlate positively lipid content observed at the ultrastructural level with the biochemical lipid analysis as a result of the relatively small amount of lipid observed in hyphal cells at the ultrastructural level.The lipid analysis indicated that the lipid content and mycelial weight reached a maximum at the 16-day period. The major fatty acids present were: C16:0, C18:0, C18:1, and C18:2. As aging occurred, the amount of unsaturation increased in the free fatty acids, the total fatty acids, and the fatty acids of the diglycerides and triglycerides. Only the fatty acids of the monoglycerides failed to increase in unsaturation. The sterol content increased slightly over the total growth period.
CO2 fixation by the blue-green alga Anacystis nidulans
Authors: Jansz E. R. , Maclean F. I.
Published: February 2010

The products of short-term (less than 1 min) 14CO2 fixation by A. nidulans were studied. The cells were not in the steady state and thus conclusions can only be drawn about possible pathways. Reproducible patterns could not be obtained. Two types of patterns were observed; in type I fixation 3-phosphoglycerate was the most heavily labeled initial product and in type II fixation the most intensely labeled initial product was aspartate. In type II patterns the bulk of the label in aspartate was in C4 suggesting a carboxylation of phosphoenolpyruvate. However, 14C incorporation into oxaloacetate was found to be much less than into aspartate. Ribulose-1,5-diphosphate carboxylase activity (sufficient to account for 20% manometric photosynthesis rates) and phosphoenolpyruvate carboxylase activity (sufficient to account for whole-cell rates of synthesis of aspartate) were observed in cell-free extracts. However, a phosphoenolpyruvate-stimulated carboxylation of ribulose diphosphate was not detected indicating that the label in aspartate was not a reflection of a pathway involving transcarboxylation of oxaloacetic acid. Early label detected in glutamate-1-14C probably arose from oxaloacetate-4-14C via the citric acid cycle rather than by the reductive carboxylation of succinic acid as α-ketoglutarate synthetase activity was not detected in extracts. In conclusion the Calvin cycle was the major route of CO2 fixation but a second, minor path of CO2 incorporation was the carboxylation of phosphoenolpyruvate.
Studies on isocitrate lyase from the facultative autotroph Thiobacillus novellus
Authors: McCarthy J. T. , Charles A. Michael
Published: February 2010

Isocitrate lyase from Thiobacillus novellus was purified about eightfold from crude extracts of acetate-grown cells. Polyacrylamide gel "disc" electrophoresis revealed that the partly purified material contained one major and two minor peaks. The optimum pH for activity in the forward direction with glycylglycine buffer and the reverse direction with either glycylglycine or potassium phosphate was around pH 8.0. Plots of v vs. s gave Michaelis–Menten kinetics with an apparent Km of 4.3 × 10−5 M for isocitrate and 2.3 × 10−4 M for succinate. However, for glyoxylate, v vs. s plots were sigmoidal. Hill plots gave an n value of 2.6 and a k value of about 7.76 × 10−5 M. Since biosynthetic enzymes usually have sigmoidal kinetics, it follows that isocitrate lyase may be important in the synthesis of isocitrate. Also of interest was the finding that the enzyme did not show an absolute requirement for a divalent cation, but in the presence of 0.3 mM Mg2+ activity was stimulated about threefold over that observed in the absence of metal. Km for Mg2+ was 7.0 × 10−4 M. Complete loss of activity found on addition of 0.03 mM HgCl2 or CuSO4 to the enzyme in the absence of Mg2+, as well as the restoration of activity lost during storage by the addition of cysteine or glutathione supports the idea that sulfhydryl groups are required for activity. The effect of adenine nucleotides on activity revealed in decreasing order of inhibition that ATP > ADP > AMP. Adenosine or pyrophosphate were not inhibitory at any concentration.
Antigenic homogeneity of enterotoxin from different agglutinating serotypes of Clostridium perfringens
Authors: Niilo L.
Published: February 2010

Fifteen strains of Clostridium perfringens type A which included Hobbs' agglutinating serotypes 1 to 13 and two unknown serotypes were studied with respect to the serological nature and the quantity of enterotoxin produced. Ten of the 13 serotypes, and the two unknown ones, produced enterotoxin while three strains (serotypes 4, 5, and 7) failed to do so. Enterotoxins from the producing strains showed a line of identity in immunodiffusion tests using specific antiserum to enterotoxin, and they exhibited similar erythemal and enteropathogenic effects. Enterotoxin was produced only when these strains sporulated, but spore producing, nonenterotoxigenic strains were encountered.
Sensitivity to myxin of Escherichia coli treated with ethylenediaminetetraacetic acid
Authors: Lesley S. M. , Behki R. M.
Published: February 2010

Sensitivity to the antibiotic myxin was significantly increased in Escherichia coli 15T− cells treated with ethylenediaminetetraacetic acid (2 mM) for 5 min. This treatment did not reverse the resistance to myxin in cells of a myxin-resistant strain. Cells of both the susceptible and the resistant strains accumulated myxin intracellularly to the same extent.
Availability and specificity of lipopolysaccharide on the surface of 56 °C heated Bordetella pertussis
Authors: Aprile M. A. , Wardlaw A. C.
Published: February 2010

The technique of hemagglutination-inhibition was used to study the availability and specificity of Bordetella pertussis lipopolysaccharide (LPS) on the cell surface of 10 strains of B. pertussis.It was found that all B. pertussis strains studied possessed freely accessible LPS determinant groups on their cell surfaces and that these determinants, designated A, B, D, and E, were distributed so that strains possessed either A and E or B and D. There was no correlation between the pattern of LPS determinants and the Phase status of the strains.
Degradation of poliovirus RNA in vivo
Authors: Adler R. , Garfinkle B. D. , Mitchell W. , Tershak D. R.
Published: February 2010

From 15 to 20% of the RNA of virulent strains of poliovirus is degraded at 35 °C several hours after maximal synthesis is reached. From 20 to 30% of the RNA of attenuated viruses is degraded under the same conditions. Cultures placed at 40 °C in the presence of 3 mM guanidine during the linear stage of RNA synthesis lead to breakdown of 15 to 40% of the RNA of virulent viruses and 30 to 40% of the RNA of attenuated viruses. It is doubtful that breakdown of RNA alone can explain the temperature sensitivity of attenuated viruses.
Enhancement of interferon production of murine peritoneal leukocytes by mineral oil: the effect in experimental EMC infection in mice
Authors: Mendelson J. , Dick V.
Published: February 2010

Mineral oil enhanced production of interferon in vitro by murine peritoneal leukocytes when the latter were challenged with encephalomyocarditis virus (EMC). Serum interferon titers were significantly elevated in those animals that were infected with EMC and had received an intraperitoneal injection of mineral oil. In experimental EMC infections in vivo, a single intraperitoneal injection of mineral oil resulted in a marked decrease in mortality in those animals receiving the injection.
Role of Na+ and K+ in preventing lysis of a slightly halophilic Vibrio alginolyticus
Authors: Unemoto Tsutomu , Tsuruoka Tsutomu , Hayashi Makoto
Published: February 2010

In preventing the lysis of a slightly halophilic marine Vibrio alginolyticus, Na+ acted cooperatively with Mg2+, while K+ counteracted the effect of Na+ and Mg2+. When the cells were washed with a medium containing NaCl lower than that of the growth medium, the intracellular K+ was released from the cells and the minimum concentration of KCl for preventing cell lysis (lysis point for KCl) decreased in parallel to the concentrations of NaCl in the washing medium. The lysis points for KCl were increased by increasing NaCl in the growth medium. Rates of the initial rapid lysis measured by a stopped-flow method were dependent on the concentrations of KCl to which the cells were transferred. On the other hand, the lysis point for NaCl was unaffected by the concentrations of NaCl in the washing medium or in the growth medium. The results have been interpreted as indicating that Na+ prevented the cell lysis by providing the sufficient mechanical strength of the envelope against mechanical stress and that K+ prevented the cell lysis by balancing the internal osmotic pressure of the cells.
Experimental immunization with attenuated mutants of Pseudomonas aeruginosa
Authors: Syeklocha Delfa
Published: February 2010

Two attenuated mutants of Pseudomonas aeruginosa (PA7), designated P-8 and P-11, were tested for their immunizing potential in mice. One or three sublethal doses of viable cells of either mutant given by the intraperitoneal route did not increase the resistance of the animals even with time, to challenge with the virulent parent form. However, increased survival was obtained in groups of mice immunized with six doses of either a viable or formalinized preparation of the P-8 mutant, injected intraperitoneally or intravenously. An elevated specific antibody response was found only in the sera of animals immunized with the largest doses of P-8 and this antiserum protected normal animals when given intraperitoneally 4 h before challenge.The two mutants appear to be similar, if not identical, with the parent form, with the exception of their slower growth in complex medium and their reduced virulence for mice.
Thermally caused filament formation in the psychrophile Bacillus insolitus
Authors: Ferroni G. D. , Inniss W. E.
Published: February 2010

The formation of filaments by cells of the psychrophile, Bacillus insolitus, occurred at 30C but not at 20C. Determination of the distribution pattern of the lengths of cells grown at 20 and 30C showed that the number of longer cells continually increased at 30C up to about 12 h of incubation when 83% of the cells grown at 30C were at least 3 times as long as 87% of the cells grown at 20C. The synthesis of DNA corresponded to the amount of growth which occurred at 30C as well as at 20C, indicating that the cell elongation was not caused by the prevention of DNA synthesis at the higher temperature. The fact that the filaments were found to be multinucleated supported this conclusion.
Incorporation of adenine and uracil into the nucleic acids of Streptococcus bovis
Authors: Smith Robert C. , Mathur Carolyn F.
Published: February 2010

Adenine-8-14C and uracil-2-14C were rapidly taken up and incorporated into the nucleic acids of Streptococcus bovis and mixed cultures of rumen bacteria. The radioactivity from adenine-8-14C was found in both the adenine and guanine of RNA and DNA. The radioactivity from uracil-2-14C was found in the uracil and cytosine of RNA and the cytosine and thymine of DNA. With both precursors there was 10–12 times as much radioactivity in the RNA as there was in the DNA. Thymine-2-14C was not used by Streptococcus bovis or the rumen bacteria.
Ribosome-covered vesicles associated with synthesis and secretion of invertase in yeast
Authors: Holley Richard A. , Sweeny Phillip R. , Kidby Denis K.
Published: February 2010

A ribosome-covered vesicle population in Saccharomyces cerevisiae M1016 shows a marked increase when invertase synthesis is derepressed. These structures have not been reported previously. It is suggested that these structures may be related to the synthesis and secretion of invertase.
Susceptibility of McCoy cells to infection by Chlamydia psittaci
Authors: Lewis Vester J. , Thacker W. Lanier
Published: February 2010

Irradiated McCoy cell cultures were susceptible to infection with all of six psittacosis isolates tested. The organisms could be demonstrated readily in infected mouse brain suspensions by inoculation (0.5 ml) of irradiated cells with dilutions killing 50% of weanling mice inoculated intracerebrally (0.03 ml). Staining of the inoculated monolayers with Gimenez or fluorescent antibody stain and inspecting microscopically for presence of the organism was a more sensitive test than mere observation of the cultures for cytopathic effect. Irradiation of McCoy cells increased their susceptibility.An advantage of the McCoy system over the use of mice is that it requires only a 7-day test period rather than a 21-day test period. One disadvantage is the need to stain and examine each inoculated culture; in addition, irradiation facilities must be available.
Two-step centrifugation method. A simplification of the density-gradient procedure for the purification of influenza virus
Authors: Arora D. J. S. , Pavilanis V. , Robert P.
Published: February 2010

In the present investigation, centrifugation of an influenza virus preparation by the sucrose density-gradient method was carried out to determine the "upper" and "lower" concentrations of sucrose at which viral activity resided. Virus was suspended in an "upper" concentration of sucrose and was centrifuged, thus resulting in a suspension containing virus free from impurities. The sucrose concentration in the suspension containing virus was then reduced to the "lower" concentration of sucrose and the suspension was recentrifuged. Virus particles sedimented, leaving impurities in the suspension. As well as achieving the same degree of purification of the virus sample as obtained by density-gradient centrifugation, this method also succeeded in concentrating influenza virus.
Effect of endotoxin administration on the growth of Candida albicans in sera from various species
Authors: Elin Ronald J. , Wolff Sheldon M.
Published: February 2010

The ability of sera from five different animal species to support the growth of C. albicans before and after the animals were inoculated with bacterial endotoxin was studied. A significant diminution was found of the in vitro growth of C. albicans in sera from four (man, rabbit, guinea pig, and mouse) of the five animal species inoculated with bacterial endotoxin 24 h before bleeding when compared with control sera. These findings suggest that the previously reported in vivo non-specific resistance to infection induced by bacterial endotoxin as measured by lethality in the mouse is probably present in man, the rabbit, and the guinea pig. No decrease in the growth of C. albicans was found in sera from dogs inoculated with bacterial endotoxin.
Marine basidiomycetous yeasts (Rhodosporidium spp. n.) with tetrapolar and multiple allelic bipolar mating systems
Authors: Fell Jack W. , Hunter Ingrid L. , Tallman Adele S.
Published: February 2010

Studies of the mating systems of basidiomycetous yeasts from oceanic regions demonstrate that Rhodosporidium bisporidiis sp. n. and Rhodosporidium dacryoidum sp. n. have tetrapolar mating factors. Rhodosporidium infirmo-miniatum sp. n. is bipolar with three known alleles. The formal description of these three species is presented, as well as that of Rhodosporidium capitatum sp. n., a self-sporulating form. Rhodosporidium capitatum and Rhodosporidium bisporidiis are distinguished by the formation of basidia with terminal sporidia that develop on primary sporidia. The sporidia are not forcefully ejected. Rhodosporidium infirmo-miniatum has short basidia with terminal sporidia, but lacks primary sporidia. Rhodosporidium dacryoidum has two- to four-celled basidia with lateral sporidia. Rhodosporidium capitatum, Rhodosporidium infirmo-miniatum, and Rhodosporidium bisporidiis produce endospores. The taxonomic status of these species, and of the basidiomycetous yeast-like genera, is discussed.
Purification and characterization of a lytic peptidase produced by Bdellovibrio bacteriovorus 6-5-S
Authors: Fackrell H. B. , Robinson J.
Published: February 2010

Bdellovibrio bacteriovorus 6-5-S releases at least two enzymes into the culture fluid when grown on autoclaved cells of Spirillum serpens VHL. One of the enzymes is bacteriolytic and the other is proteolytic. The lytic enzyme was purified by a factor of 3000 using ammonium sulfate fractionation, Sephadex G-100 gel filtration, and the anion exchanger DEAE-Sephadex. The lytic enzyme degrades peptidoglycan of S. serpens by hydrolyzing the diaminopimelic acid – alanine bond in the tetrapeptide chain. Ca2+ or Mg2+ exerted little or no effect on the activity of the lytic enzyme. The enzyme had a molecular weight of 40 000 as indicated by gel filtration. Crude preparations were unstable at 4C. The second enzyme, a protease that digested Azocoll, was purified by a factor of 7 by ammonium sulfate fractionation followed by gel filtration with Sephadex G-100. The protease was eluted in the void volume from a Sephadex G-100 column and therefore may have a molecular weight of at least 100 000. Its activity was enhanced by additions of Ca2+ and Mg2+. The enzyme was stable at 4C.
Spheroplast formation by an anaerobic gram-negative bacterium Bacteroides ruminicola
Authors: Cheng K. -J.
Published: February 2010

The spontaneous formation of spheroplasts was observed in stationary phase cultures and in aging cultures of Bacteroides ruminicola when grown in synthetic or a rumen fluid medium. Unlike most other gram-negative bacteria, spheroplasts of this organism also were formed when log-phase cells were treated with lysozyme in the presence of 0.01 M Mg2+ in 0.01 M Tris, pH 8.4.
Autodegradation of RNA of bacterial ribosomes
Authors: Gagnon C. , Lamirande G. de
Published: February 2010

The autodegradation capacity of ribosomes, in the presence or absence of EDTA, has been studied in resting and dividing bacteria. This capacity, in the presence of EDTA, was found to be much lower in the ribosomes of log-phase bacteria when compared to stationary phase bacteria. In absence of EDTA, autodegradation was not observed. However, ribosomal profiles, as determined on sucrose gradients after incubation at 37 °C, showed that the polysomes have been transformed into monomers indicating that the absence of autodegradation was only apparent.
A cluster of mutations determining erythromycin resistance in Bacillus subtilis
Authors: Chu C.-Y. , Iyer V. N.
Published: February 2010

Forty erythromycin-resistant mutants of Bacillus subtilis strain 168 were isolated as spontaneous mutants or after induction with 2-aminopurine. They showed different levels of resistance and six of these mutants were studied genetically using transformation reactions. Recombination of some pairs of mutations has a synergistic effect on resistance. All six mutants are clustered on the B. subtilis chromosome between the genes str conferring streptomycin resistance and pur B determining purine biosynthesis. Some mutations overlap at the same site. The genetic order of these ery mutations with respect to one another and a streptomycin-resistant mutation str has been determined.
Natural habitat of Caryophanon latum
Authors: Trentini W. C. , Machen C.
Published: February 2010

When samples of fresh dung from pigs, horses, sheep, or cattle were enriched to encourage the growth of Caryophanon latum, the organism was found to be specifically associated with cattle dung. Several sheep dung samples were found to be positive for C. latum, but all were taken from a pasture where sheep and cattle were grazed together. All samples taken from sheep not pastured with cattle were negative. Autoclaved samples of cattle, horse, and sheep dung all supported growth and natural morphology of C. latum when inoculated with pure or mixed cultures of this organism. A large proportion of autoclaved cattle dung samples left open to the air of cattle barns or occupied cattle pastures showed the presence of C. latum after 1–4 days exposure. Control samples exposed to air in areas far removed from cattle were uniformly negative. Aseptically collected "free catch" samples from cattle were mainly negative, as were samples collected from the fistulated rumen. Enrichment of various other sources was undertaken. Our total findings support the hypothesis that C. latum is a natural, specific, and temporary resident of cattle dung and is dispersed to new droppings by contaminated air and also probably by flying insects or cattle movement.
Dissociation in a marine pseudomonad
Authors: Gow John A. , DeVoe I. W. , MacLeod Robert A.
Published: February 2010

Eight morphological variants, the product of colonial dissociation, were isolated from cultures of the marine pseudomonad B-16. Features which distinguished the variants were smooth versus rough colony type, the presence or absence of color, and differences in colony diameter. The variants differed in their capacity to form stable protoplasts and to grow at suboptimal Na+ concentrations in defined medium. All, however, required Na+ for growth. The ability of the organism to accumulate α-aminoisobutyric acid (AIB) and the requirement for Na+ for this process was not affected by dissociation.
Extracellular carbohydrate antigens from some non-pathogenic Neisseria species
Authors: Wagner G. H. , Cooper F. P. , Bishop C. T.
Published: February 2010

Thirteen species of Neisseria were examined for the presence of extracellular carbohydrate antigens. Of three media tested for optimum growth of the bacteria, yield of antigens, and ease of isolation of antigens, dialyzed tryptic soy broth was the best. Seven species, N. catarrhalis, N. cinerea, N. flava, N. flavescens, N. lactamicus, N. subflava, and N. winogradski, yielded extracellular antigens that were extractable into phenol and hence were probably proteinaceous. The remaining six species, N. canis, N. caviae, N. cuniculi, N. cuniculi subsp. gigantea, N. denitrificans, and N. sicca, yielded carbohydrate antigens that were purified by a sequence of phenol extraction, chromatography, enzymic digestion, and membrane filtration. These antigens were polymers of 2-acetamido-2-deoxy-D-glucose and 2-acetamido-2-deoxy-D-galactose, the latter being the only constituent of the antigens from N. caviae and N. sicca. Cross-reactivities of the carbohydrate antigens in the homologous antisera showed that there were close relations between the antigens from N. canis and N. cuniculi subsp. gigantea and also between those from N. caviae and N. sicca.
Regulation of sexual reproduction in Gibberella zeae (Fusarium roseum 'Graminearum') by F-2 (Zearalenone)
Authors: Wolf J. C. , Mirocha C. J.
Published: February 2010

Zearalenone or F-2 [2,4-dihydroxy-6-(10-hydroxy-6-oxo-trans-1-undecenyl)-benzoic acid lactone] is an estrogenic mycotoxin synthesized by Fusarium roseum (Link emend.) Sny. & Hans. 'Graminearum.' In addition to its estrogenic activity in animals, it acts as a sex-regulating hormone in F. roseum, and this is the subject of this paper. When amounts of F-2 ranging from 0.1 ng to 10.0 ng were applied to a 1.0-cm diameter disk of Coons' synthetic medium in agar, perithecial formation was enhanced by as much as 100%. Amounts in excess of 10.0 μg inhibited perithecial formation. F-2 has a periodicity of action relative to both enhancement and inhibition of perithecial formation. The ability of F-2 to enhance was greatest up to 4 days of culture age when amounts optimum (0.1 ng and 1.0 ng) for enhancement were used. Optimum inhibition of perithecial formation with inhibitory amounts (10.0 μg and 100.0 μg) occurred when the culture was from 3 to 4 days old. Dichlorvos (2,2-dichlorovinyl dimethyl phosphate), also called VAPONA, inhibited F-2 biosynthesis as well as production of perithecia. Moreover, when F-2 was applied simultaneously with dichlorvos, the inhibition caused by dichlorvos was reduced. A limited study on structure activity relationships was done with the conclusion that the hydroxyl or ketone in the 6′ position of the undecenyl ring is necessary for activity. Further, unsaturation at the 1′,2′ position on the undecenyl ring of F-2 is associated with inhibitory activity at the higher concentrations.
On the Gram reaction of Caryophanon latum
Authors: Smith D. L. , Trentini W. C.
Published: February 2010

When Caryophanon latum was grown such that natural morphology was the major criterion of adequate growth, it was consistently found to be Gram-positive. Treatment with "Gram-specific" antibiotics, dyes, and other chemicals, supported this finding. The effect of various growth conditions (pH, nutrition, and temperature) on the Gram reaction was studied. Variable staining results occurred when growth conditions supported poor morphology of C. latum. The Gram-negative reaction of this organism obtained by some other workers is attributed to inadequate nutritional or other conditions which result in abnormal morphology.
Immunological reactions of Mycobacterium leprae and Mycobacterium lepraemurium grown in cayman
Authors: Kwapinski J. B. G. , Kwapinski Elke H.
Published: February 2010

Caymans injected with live M. leprae or M. lepraemurium died within 8 weeks. Sections made from their lymph nodes and spleen revealed areas of histiocyte infiltrations, fuchsinophilic histiocytes, and acid-fast bacilli. Extracts from the organs reacted with anti-M. leprae and anti-M. lepraemurium anti-sera; and sera of the infected caymans reacted with the cytoplasms of M. leprae and M. lepraemurium, indicating an immunological identity of the antigens.
Enzymic hydrolysis of the potassium chloride soluble fraction of carrageenan: properties of "λ-carrageenases" from Pseudomonas carrageenovora
Authors: Johnston K. H. , McCandless E. L.
Published: February 2010

An enzyme complex which hydrolyzed the KCl soluble carrageenan extracted from the red alga Chondrus crispus has been isolated from the cell-free medium of a culture of Pseudomonas carrageenovora grown on this polysaccharide. Three hydrolases could be separated. Fraction I, which caused a rapid decrease in the specific viscosity of the polysaccharide preparation with only minimal release of reducing sugar, could be distinguished from fraction II chromatographically on Sephadex G-100 and electrophoretically on agarose gel. Fraction IIa caused release of reducing sugar at pH 6.2, which activity was depressed at pH 7.5. Fraction IIb exhibited viscometric activity only at both pH 6.2 and pH 7.5. Fraction IIa had a sharp pH optimum at pH 6.2 and a temperature optimum at 28°. All hydrolases were inactivated by freezing, by dialysis against distilled water, by heating at 35° for 30 min, and by Hg2+ and 0.0001 mM EDTA. When fraction II (a and b) isolated after chromatographic resolution on Sephadex G-100 was incubated at pH 6.2 with KCl soluble carrageenan from C. crispus, products which had Rgal values of 0.74 and 0.17 were detected, were sulfated, and contained no 3,6-anhydrogalactose.
Chemical changes in the cell walls of conidia of Penicillium notatum during germination
Authors: Martin J. F. , Nicolas G. , Villanueva J. R.
Published: February 2010

Conidial and mycelial cell walls of Penicillium notatum were found to be chemically different, the main differences being in the distribution of amino acids, neutral sugars, and amino sugars. The amino acid content was higher in conidial than in hyphal walls but individual amino acids found in spore and mycelial walls were essentially the same, except for basic amino acids (histidine, arginine, and lysine) of which only traces were present in mycelial walls.Four neutral sugars (glucose, galactose, mannose, and rhamnose) were detected in walls of resting spores, but rhamnose was absent at other stages of germination. Galactose was the most abundant sugar in walls of resting spores, while glucose was the main component of hyphal walls. Only one hexosamine (glucosamine) was found in walls of resting and swollen spores but galactosamine was present in walls of germinating spores and mycelium. The content of both amino sugars greatly increased during germination.
Ultrastructural changes in the conidia of Penicillium notatum during germination
Authors: Martin J. F. , Uruburu F. , Villanueva J. R.
Published: February 2010

To study the changes in the cell wall of Penicillium notatum during germination, thin sections of resting, swollen, and germinating spores, and mycelium were compared with thin sections of the isolated cell walls. In the cell wall of resting spores four distinct layers were found. The outermost layer of the cell wall of resting spores was released during swelling and the two inner layers were extended to form the cell wall of the germ tube. The cell wall of young germ tubes had only two layers but a new electron-dense layer was formed later on the outside. Mycelial cell walls which appeared thinner than those of conidia showed three distinct layers. Large mitochondria that divide during germination were present in both resting and swollen spores. Two different types of vacuoles were found, both of which decreased in size and in number during germination. Endoplasmic reticulum was almost absent in resting spores but increased substantially during swelling.
Carbohydrate metabolism in the Plasmodium of the myxomycete Physarum flavicomum
Authors: Lynch Thomas J. , Henney Jr. Henry R.
Published: February 2010

Carbohydrate metabolism in the growing plasmodial phase of Physarum flavicomum was studied in partially defined media using the radiorespirometric technique and specifically labeled 14C-substrates. The Embden–Meyerhof–Parnas (EMP) – tricarboxylic acid cycle (TCA) and the pentose phosphate pathways are the routes by which glucose is used by this myxomycete. The replacement of the usual citrate–phosphate buffer by succinate–phosphate results in a decreased uptake of 14C-glucose from the medium and a corresponding decline in the rate of interval 14CO2 evolution. The addition of an inorganic nitrogen source (ammonium nitrate) to the medium also decreases the rate of carbohydrate metabolism and alters the relative participation of the pathways by favoring the EMP–TCA. Supplementing the medium with cyclic-3′-5′-adenosine monophosphate produces a transient stimulation of the rate of metabolism by the EMP–TCA. The Plasmodium is relatively impermeable to gluconate and pyruvate and does not readily metabolize amino acids.
Effect of glucose and pH on growth and enterotoxin B synthesis by Staphylococcus aureus, strain S6, after heat injury in sodium or potassium phosphate buffer
Authors: Hurst A. , Collins-Thompson D. L. , Kruse H.
Published: February 2010

Cells injured by heating at 52C for 15 min in sodium (Na cells) or potassium phosphate buffer (K cells) were allowed to grow and recover in media containing 0, 0.1%, and 1.0% glucose. Growth, acid, and enterotoxin B production was followed and compared with that of unheated control cells. Control cells growing in 0 and 0.1% glucose first lowered the pH, but injured cells did not. Straight lines were obtained from growth experiments when the ratio enterotoxin B/pH versus time was plotted. Statistical analysis of the slopes showed that Na cells differed from K cells. In 1.0% glucose, Na cells produced less acid than K cells. Na cells were 80%, control cells were 90%, and K cells were 99% repressed in their enterotoxin B synthesis. At all glucose levels, the lag phase of Na cells was about 2 h shorter than that of K cells. Heat injury caused a 30–40% loss of K+, but Na cells gained Na+ (34%) and K cells lost Na+ (28%). The K/Na ratio of Na cells was 2.75 and that of K cells was 15.75. It is argued that this difference could account for the differences observed between Na cells and K cells but cannot account for the total injury phenomenon.
Electron microscope and physical chemical characterization of C-phycocyanin from fresh extracts of two blue-green algae
Authors: Kessel Martin , MacColl Robert , Berns Donald S. , Edwards Mercedes R.
Published: February 2010

The particulate material (intact and dissociated phycobilisomes), adjacent to the thylakoids of Plectonema boryanum and Calothrix parietina, was examined in thin sections and in freshly prepared C-phycocyanin extracts. For the latter a method was developed using spheroplasts of log-phase cells. When examined by sedimentation velocity centrifugation, the sedimentation coefficients of the rapidly extracted C-phycocyanin were found to be 18 S and 5 S. Also, a 10-S boundary was observed with P. boryanum. When C. parietina was grown under red light the 18-S aggregates increased to 20 S. The 18 S particles, in electron micrographs of negatively stained preparations, displayed eight subunits surrounding a central one. The possibility that some subunits fall out of the plane of view is contemplated in proposing a dodecamer arrangement for such particles. The 20-S particles were also examined by electron microscopy. However, the precise number of monomer units associated with either the 18-S or 20-S particles has not yet been ascertained. Thin sections of intact algal cells are presented to demonstrate the presence of phycobilisomes along the outer faces of the thylakoid membranes.
Separation of soluble denitrifying enzymes and cytochromes from Pseudomonas perfectomarinus
Authors: Cox Jr. C. D. , Payne W. J.
Published: February 2010

Nitrite and nitric oxide reductases were found soluble in extracts of Pseudomonas perfectomarinus cultured anaerobically at the expense of nitrate and ruptured with the French pressure cell. Malic enzyme, transhydrogenase, and flavin reductase that provided electron flow for these reductases were soluble as well. Nitrous oxide reductase remained particle-bound. Exogenous NADH was a poor electron donor for crude extracts, but a combination of malate, NADP, and NAD served well in the reduction of nitrite and nitric oxide. Nitrite reductase activity lost on dialysis of crude extract was restored by addition of this combination. Addition of free flavins was required for reduction of nitrite and nitric oxide. A nitrite reductase complex was separated from the nitric oxide reductase by gel filtration and DEAE-cellulose chromatography. NADH was an effective electron donor for this system with flavins provided as well. A c-type cytochrome with a split-α peak (perhaps associated with a d type) and two additional c-type cytochromes were separated from the nitrite reductase fraction. One of the latter (RI) emerged oxidized, the other (RII) reduced. Only nitric oxide oxidized RII. When these cytochromes were added to reaction mixtures containing nitrite reductase, activity was increased most by the split-α fraction. After reduction with dithionite, the absorption spectrum of the split-α cytochrome was returned to the oxidized spectrum by addition of nitrite but not the other oxides. A significant amount of a c-type cytochrome remained bound to the nitric oxide reductase fraction. A combination of malic acid, NAD, and NADP was more effective than NADH as electron donor for this system with free flavins provided as well. Addition of RI increased the rate of nitric oxide reduction by this fraction.
The effect of solute concentration on the shape of the trypanosomatid flagellate Crithidia fasciculata
Authors: Maclean F. I. , Amiro E. R.
Published: February 2010

When grown in proteose-peptone medium Crithidia fasciculata becomes round after it enters the stationary phase. This change in shape can be prevented when NaCl, sucrose, mannitol, or glucose is present in the concentration range 150–200 mM. KCl had relatively weak activity in preventing the change of shape and LiCl, CsCl, and RbCl inhibited growth in the concentration range where NaCl was effective.
Purification of Clostridium perfringens type C theta toxin
Authors: Hauschild A. H. W. , Lecroisey A. , Alouf J. E.
Published: February 2010

Clostridium perfringens type C theta toxin was purified by ammonium sulfate precipitation, gel filtration, and ion-exchange chromatography. The purified toxin was free of alpha, beta, delta, and kappa toxins. Electrophoresis of the toxin in both the anionic polyacrylamide disc gel and in the polyacrylamide dodecyl sulfate gel yielded single protein bands. L-Lysine was determined as the sole N-terminal amino acid. The specific hemolytic activities of two purified preparations were 3.6 × 106 and 4.8 × 106 HU/mg N; the specific toxicities were 8.1 × 103 and 7.7 × 103 mouse MLD/mg N. The molecular weight determined by the polyacrylamide – dodecyl sulfate method was 74 000.
Ultrastructural studies of Chlamydia psittaci 6BC variant strains. I. Ultrastructure of the surface layers of egg-passaged 6BC strain
Authors: Poffenroth Linda , Costerton J. W. , Kordová Nonna , Wilt John C.
Published: February 2010

Electron microscopic examination of a semipurified Chlamydia psittaci 6BC strain attenuated in chick embryo yolk sac revealed for the first time two morphologically distinct small elementary bodies which differ both in the ultrastructure of their surface layers and in their buoyant densities in sucrose gradients. Also, the morphology of the surface layers of the larger reticulate forms in cell-free systems is described for the first time. Many points of difference between the surface envelopes and internal structure of chlamydial particles and those of Gram-negative bacteria are discussed.
Virulence of nocardiae
Authors: Ochoa Antonio Gonzalez
Published: February 2010

The virulence of Nocardia brasiliensis, N. asteroides, and N. caviae was investigated. The study was done by inoculation of these organisms into the footpad of white mice. The results show that N. brasiliensis has greater virulence than N. asteroides and N. caviae. These observations resemble clinical findings in which N. brasiliensis acts as an obligatory pathogenic agent, whereas N. asteroides usually behaves as an opportunistic pathogen. Nocardia caviae, which is very similar to N. asteroides from the taxonomic standpoint, is only rarely a causative agent for mycetoma.
Lomasome development in Rhizopus stolonifer sporangiospores during anaerobiosis
Authors: Bussel J. , Sommer N. F.
Published: February 2010

Numerous well-developed lomasomes appeared in Rhizopus stolonifer sporangiospores in response to anoxia. The lomasomes usually appeared between the plasmalemma and the inner cell wall, though some were found as deeply invaginated channels of the plasmalemma. Hence, lomasome configuration depended on the sectioning plane of the spore. They appeared either as a boundary structure or as an isolated inclusion within the cytoplasm. It is suggested that lomasomes in R. stolonifer sporangiospores arise by elaboration of the plasmalemma, developing in association with the increasing thickness of the inner spore wall.