bluuebunny/crossref_metadata_2025 huggingface dataset:
Brucellosis in reindeer, Rangifer tarandus L., inoculated experimentally with Brucella suis, type 4
Authors: Rausch R. L. , Huntley B. E.
Published: April 2010

An investigation of brucellosis caused by Brucella suis, type 4, in reindeer, Rangifer tarandus L., and other ungulates inoculated experimentally with virulent isolates was undertaken to observe the course of infection, follow titres of serum agglutinins, and determine the extent to which intraspecific and interspecific transmission might occur among confined animals. Titres rose to maximum levels within 1 to 2 months following inoculation, decreased during the next 4 months, and persisted at low levels thereafter. Titres in uninoculated associates of these animals followed the same pattern, but at lower levels. Abortion occurred in reindeer that received large numbers of organisms; females receiving smaller numbers at an earlier stage of gestation produced normal fawns. Possible explanations for the holarctic distribution of B. suis, type 4, in reindeer are considered.
Inducing effect of plant cells on nitrogenase activity by Spirillum and Rhizobium in vitro
Authors: Child J. J. , Kurz W. G. W.
Published: April 2010

Eleven different plant cell tissue cultures of both legume and non-legume origin have been grown in direct association, and in separate but close proximal association with both Spirillum lipoferum and Rhizobium sp. 32H1. Basic similarities were found in the nutritional requirement for the induction of nitrogenase activity (C2H2) in both organisms. In the absence of plant cell cultures both organisms need to be provided with a pentose sugar and a tricarboxylic acid to induce high levels of nitrogen-fixing activity. Plant cell callus tissue appears only capable of supplying the tricarboxylic acids needed but not the sugar component. The plant tissue, however, seems able to activate certain carbohydrates, which in themselves are incapable of substituting for the pentose additive.
Acetate metabolism in Escherichia coli
Authors: Lakshmi T. M. , Helling Robert B.
Published: April 2010

Levels of several intermediary metabolites were measured in cells grown in acetate medium in order to test the hypothesis that the glyoxylate cycle is repressed by phosphoenolpyruvate (PEP). Wild-type cells had less PEP than either isocitrate dehydrogenase – deficient cells (which had greater isocitrate lyase activity than the wild type) or isocitrate dehydrogenase – deficient, citrate synthase – deficient cells (which are poorly inducible). Thus induction of the glyoxylate cycle is more complicated than a simple function of PEP concentration. No correlation between enzyme activity and the level of oxaloacetate, pyruvate, or citrate was found either. Citrate was synthesized in citrate synthase – deficient mutants, possibly via citrate lyase.
Neisseria gonorrhoeae: evaluation of some methods used for carbohydrate utilization
Authors: Shtibel Rosa , Toma S.
Published: April 2010

A total of 989 Neisseria gonorrhoeae cultures were examined for acid production from dextrose in seven different carbohydrate media. Four of these media were found to be quite accurate for this purpose. Some pitfalls in the preparation and usage of cystine trypticase agar carbohydrate media are discussed. The term 'fermentation' of carbohydrates by Neisseria species is inaccurate and responsible for some N. gonorrhoeae false-dextrose-negative results.
Human neutrophil – mediated destruction of antibody sensitized herpes simplex virus type I infected cells
Authors: Fujimiya Yoshaiki , Rouse Barry T. , Babiuk Lorne A.
Published: April 2010

Human peripheral blood polymorphonuclear neutrophils (PMN) were tested for their ability to act as effector cells in antibody-dependent cell cytotoxicity (ADCC) against Herpes simplex virus (HSV) infected target cells sensitized with anti-HSV serum. The PMN from all 29 individuals tested could mediate ADCC in the presence of a standard human anti-HSV serum. Since PMN are prominent cells early in herpes lesions, it was hypothesized that because ADCC could represent an in vitro model for antiviral recovery, perhaps the efficacy of PMN at mediating ADCC might be impaired in those subject to frequent recrudescent herpes. However, evidence for the hypothesis was not obtained since the PMN from individuals with frequent, infrequent, or unrecorded herpes labialis all showed approximately the same activity at mediating ADCC. Alternative ways in which PMN could be involved in antiviral recovery were discussed.
Cleavage planes in the envelope of Aquaspirillum bengal
Authors: Beveridge T. J. , Hall M. , Murray R. G. E.
Published: April 2010

The cell surface of Aquaspirillum bengal was devoid of superficial wall structure. When cells were freeze-cleaved and etched, multiple fracture planes through the cell envelope were exposed, which was unusual for an aquaspirillum. These included both convex and concave surfaces and they are compared with those of other gram-negative bacteria.
Labelled acetone and levulinic acid are formed when [14C]acetate is being converted to mycophenolic acid in Penicillium brevicompactum
Authors: Nulton Carter P. , Campbell Iain M.
Published: April 2010

Evidence is presented that is compatible with the hypothesis that the farnesyl unit involved in the biosynthesis of mycophenolic acid in Penicillium brevicompactum is degraded by two successive oxidative cleavages at the double bonds distal from the phthalide nucleus. Acetone and levulinic acid are two non-aromatic degradation products.
Biosynthesis of chloramphenicol in Streptomyces sp. 3022a. Properties of an aminotransferase accepting p-aminophenylalanine as a substrate
Authors: Jones A. , Francis M. M. , Vining L. C. , Westlake D. W. S.
Published: April 2010

In the presence of α-ketoglutarate, cell-free extracts of Streptomyces species 3022a catalysed transfer of the amino group from p-aminophenylalanine, yielding an unstable product similar to that obtained by the action of D- and L-amino acid oxidases on the amino acid. The enzyme, purified 16-fold from cell homogenates by chromatography on ion-exchange celluloses, hydroxyapatite, and cross-linked dextran gel, has a molecular weight of 90 000 and a broad pH optimum at 8.0. It is active with L-phenylalanine and L-tyrosine as well as p-amino-DL-phenylalanine as amino donors, and its relative activity towards these substrates did not change during purification. Polyacrylamide disc-gel electrophoresis of the partially purified enzyme gave single zones with identical mobility when the gels were assayed for activity with p-aminophenylalanine and tyrosine as amino donors. The results indicate that synthesis of p-aminophenylalanine en route to chloramphenicol uses a multispecific aminotransferase for aromatic amino acids. With L-phenylalanine as substrate, the preferred amino-accepting co-substrate was α-ketoglutarate. Some kinetic constants for the enzyme were determined, and its requirement for pyridoxal phosphate was demonstrated.
In situ degradation of oil in a soil of the boreal region of the Northwest Territories
Authors: Westlake D. W. S. , Jobson A. M. , Cook F. D.
Published: April 2010

Replicate field plots comprising a control: control plus oil: control plus oil and fertilizer (urea phosphate. 27:27:0); control plus oil and bacteria: and control plus oil, fertilizer, and bacteria were established at Norman Wells, N.W.T., Canada. Plots were monitored over a 3-year period for changes in microbial numbers and the chemical composition of recovered oil. Where fertilizer was applied, there was a rapid increase in bacterial numbers, but no increase in fungal propagules. This was followed by a rapid disappearance of n-alkanes, isoprenoids, and a continuous loss in weight of saturate compounds in recovered oil. Changes in the content of asphaltenes, aromatics, and nitrogen-, sulphur-, and oxygen-containing fractions also are discussed. The seeding of oil-soaked plots with oil-degrading bacteria did not have any effect on the composition of recovered oil. Fertilized plots showed a more rapid rate of vegetation with cotton grass and Labrador tea being the dominant species in revegetation.
ICMSF methods studies. X. An international comparative study of four media for the enumeration of Staphylococcus aureus in foods
Authors: Rayman M. K. , Devoyod J. J. , Purvis U. , Kusch D. , Lanier J. , Gilbert R. J. , Till D.G. , Jarvis G. A.
Published: April 2010

An international comparative study, undertaken by six laboratories to assess the performance of four selective media commonly used for the enumeration of Staphylococcus aureus in foods, revealed that Baird-Parker agar performed most satisfactorily. There was no significant difference among milk salt, tellurite polymyxin egg yolk, and kalium rhodanid – actidione – natriumazid – eigelb – pyruvat (KRANEP) agars. The type of food examined appeared to influence the performance of the media, but no specific patterns could be determined. Cultures yielding 3+ and 4+ coagulase reactions are most likely to possess thermostable nuclease activity, and are therefore most likely to be S. aureus.
Biochemical identification of a tryptophan auxotroph in Rhodospirillum rubrum
Authors: Beauchemin-Newhouse N. , Cedergren R. J.
Published: April 2010

A tryptophan auxotroph of aerobically grown Rhodospirillum rubrum was isolated after mutagenesis and replica plating. The mutant grows on tryptophan or indole, accumulates indole glycerol phosphate, lacks the capacity to convert indole glycerol phosphate to indole, and finally is defective in photosynthetic growth. The strain is. therefore, analogous to a Trp A mutant which is defective in the α-subunit structural gene of tryptophan synthetase.
Direct observation of fungal aggregates in sand dune soil
Authors: Clough K. S. , Sutton J. C.
Published: April 2010

The mycorrhizal fungus Glomus in association with bean hosts, Phaseolus vulgaris L., growing in pot cultures and grass hosts, Calamovilfa longiflora (Hook.) Scribn and Andropogon sp. growing on Lake Huron sand dunes produced extensive external mycelium. This mycelium was the dominant factor in the aggregation of soil particles. Light and scanning electron microscope studies indicated that the sand grains were attached to the hyphae. An amorphous deposit was often present at the interfaces of sand grains and hyphae. It appeared to act as an adhesive. Staining procedures indicated that this material contained polysaccharide. Other microorganisms were observed in association with the Glomus hyphae and the amorphous deposits.
Kinetic analysis of batch and continuous culture of Streptococcus cremoris HP
Authors: Rogers P. L. , Bramall L. , McDonald I. J.
Published: April 2010

The growth of Streptococcus cremoris on a semidefined medium was studied at initial lactose concentrations of 0.2–5.0% in batch culture, and in lactose-limited chemostat cultures at 0.5% lactose. Kinetic analysis of the batch data, using statistical techniques, indicated the importance of lactose limitation and lactic acid inhibition of the growth of S. cremoris. A model for the biomass production, lactose utilization, and lactic acid production in batch culture was proposed. In continuous culture, it was found that steady state populations were maintained at higher dilution rates (D = 0.6–0.7 h−1) than the maximum predicted by batch culture (0.56 h−1). No evidence for a selection of fast-growing mutants was obtained. Copious growth adhering to the walls of the fermentor (i.e. wall growth) occurred very rapidly at higher dilution rates and this undoubtedly affected steady-state growth and wash-out and, as a consequence, the apparent maximum dilution rate.
The effects of temperature on growth of four high Arctic soil fungi in a three-phase system
Authors: Widden P. , Parkinson D.
Published: April 2010

The effect of temperature on the growth of Chrysosporium pannorum, Cylindrocarbon sp., Penicillium janthinellum, and Phoma herbarum, isolated from tundra soils, was studied. The growth in two systems, glucose–mineral agar plates and sand, moistened with glucose–mineral broth, was compared. All isolates showed an exponential increase in mass (measured as protein increase) in sand and a linear rate of extension on agar. Radial increase on agar was shown not to be a good index of growth in sand. Trends in growth rates in the sand cultures indicated that all four fungi can grow at low temperatures. The growth rate for Penicillium janthinellum at 15 °C was higher than at 20 °C, and Cylindrocarbon sp. and Phoma herbarum had higher growth rates at 2.5 °C than at 5 °C. These data suggest that there may be some adaptation by these fungi to growth in Arctic regions.
Isolation and characterization of Hfr strains of Erwinia amylovora
Authors: Pugashetti Balappa K. , Chatterjee Arun K. , Starr Mortimer P.
Published: April 2010

Hfr strains (Hfr 159 and its derivatives, Hfr 160 and Hfr 161) were constructed from Erwinia amylovora ICPB EA178 by introducing an Escherichia coli F′his+ plasmid and then selecting for integration of F′his+ after treatment with acridine orange. The Hfr strains were relatively stable upon repeated transfers on nonselective media. Interrupted mating experiments and analyses of inheritance of unselected markers showed that his+ is transferred by Hfr 159 as the proximal marker at a relatively high frequency (about 5 × 10−4 recombinants per input donor cell), followed by ilv+, orn+, arg+, pro+, rbs+, met+, trp+, leu+, ser+, and thr+ (not necessarily in that precise order). The donor strains, previously constructed in E. amylovora by integration of F'lac+ from E. coli, transfer cys+ as the proximal marker followed by ser+. Further analysis of one of those earlier donor strains, Hfr 99, showed that ser+ is followed by arg+, orn+, met+, pro+, leu+, ilv+, rbs+, his+, trp+, and thr+ (not necessarily in that precise order). Thus, the Hfr strains constructed by integration of F′his+ are different, in terms of origin and direction of transfer, from those derived from integration of F′lac+. The applicability of these Hfr strains to mapping the genes on the E. amylovora chromosome is indicated.
Physiological and biochemical characterization of aggregation-deficient mutants of Dictyostelium discoideum: detection and response to exogenous cyclic AMP
Authors: Lo E. K.-L. , Coukell M. B. , Tsang A. S. , Pickering J. L.
Published: April 2010

Forty independently isolated aggregation-deficient (Agg−) mutants of Dictyostelium discoideum, which have been partially characterized genetically, were examined for the ability to respond chemotactically to exogenous cAMP and for certain cellular and extracellular activities thought to be involved in this process. Only five of the mutants failed to produce a statistically significant chemotactic response to cAMP. When shaken in buffer, most of the Agg− mutants produced reduced levels of the cAMP-binding sites and the cell-bound cAMP phosphodiesterase reported to be components of a cell-surface cAMP receptor involved in the chemotactic response. In addition, most of the mutants failed to form contact sites A and were unable to develop on water agar plates. When the mutants were pulsed with 100 nM cAMP, 36 of 40 mutants produced detectable contact sites A and three-quarters of these strains underwent further development when placed on a solid substratum. Treatment with cAMP pulses also stimulated certain mutants to form higher levels of cAMP receptors. These observations suggest that the impaired differentiation of the plasma membrane of many Agg− mutants is due, at least in part, to the abnormal synthesis and (or) secretion of cAMP by these strains. When grown in bacterial suspension, all 40 of the mutants produced extracellular phosphodiesterase (ePD) activity, and all but 8 of the mutants secreted detectable amounts of the ePD inhibitor. In general, Agg− strains carrying mutations at the same aggregation locus (aggF–J) exhibited very similar physiological and biochemical properties.
Inhibition of protein synthesis in Streptococcus faecalis by ochratoxin A
Authors: Heller K. , Röschenthaler R.
Published: April 2010

A non-competitive inhibition of binding of cAMP to bovine protein kinase by ochratoxin A (OTA) is shown. Preliminary evidence of a protein kinase in Streptococcus faecalis is presented. The cAMP stimulation of this kinase is also inhibited by OTA. At the lowest OTA concentrations, RNA and protein synthesis are inhibited in S. faecalis. The inhibition of RNA synthesis is secondary, as in the presence of chloramphenicol no inhibition occurs for 10 min after the addition of OTA. The synthesis but not the induction of β-P-galactosidase is inhibited by OTA. The polysomes of S. faecalis are stablized after addition of OTA, showing an inhibition of peptide elongation. The mode of action of OTA in bacteria is discussed and it is concluded that inhibition of protein synthesis is the process which might be closest to the primary target of OTA.
Etude du % GC dans un groupe d'entérobactéries H2S−, apparentées au genre Citrobacter
Authors: Ferragut C. , Gavini F. , Izard D. , Leclerc H.
Published: April 2010

The deoxyribonucleic acid (DNA) of 106 strains of Enterobacteria was analysed for the guanine + cytosine (GC) content. These strains, whose origin and principal characters are described in the text, belong to the genera Citrobacter (C. freundii H2S−) and Levinea (L. malonatica and L. amalonatica). Four other groups or classes named C,D,E, and F could not be classified on the base of the usual phenotypic criteria. DNA from the strains of Levinea has a GC% of 50.3 to 53.3, while DNA from the strains of C. freundii H2S− has a GC % of 48.6 to 51.7. The representative values from the new classes are C, 50.9%; D, 54%; E, 52.7%; F, 49.5%. For the latter a genomic heterogeneity was shown, expressing itself as two subpopulations whose average GC%are 51.7 and 48.6 respectively. Statistical analysis of the averages give a significant individuality to these new classes.
Proteolytic activity of Trichoderma viride in mixed culture with Sclerotium rolfsii in soil
Authors: Rodriguez-Kabana R. , Kelley W. D. , Curl E. A.
Published: April 2010

Cultures of Sclerotium rolfsii and Trichoderma viride together in autoclaved soil were assayed at intervals during 8 days of incubation for proteolytic activity (PA) of T. viride. Significant proteolytic activity was detected only in soil containing T. viride (i.e., T. viride alone or S. rolfsii + T. viride); greatest activity occurred between 3 and 4 days after infestation and declined rapidly thereafter. Maximal PA in the mixed-culture soil was accompanied by an increase in soil pH. Optimal pH values for PA was 5.5–6.5 with a maximum at 6.0.
Inhibition of RNA polymerase from Bacillus thuringiensis and Escherichia coli by β-exotoxin
Authors: Johnson Donovan E.
Published: April 2010

The characteristics of exotoxin inhibition of deoxyribonucleic acid (DNA) dependent ribonucleic acid (RNA) polymerase isolated from Escherichia coli and Bacillus thuringiensis were investigated. RNA polymerase isolated from a variety of growth stages was partially purified and assayed using several different native and synthetic DNA templates, and exotoxin inhibition patterns were recorded for each. Although 8 to 20-h RNA polymerase extracts of E. coli retained normal sensitivity to exotoxin (50% inhibition at a concentration of 7.5 × 10−6 M exotoxin), RNA polymerase isolated from late exponential and ensuing stationary-phase cultures of B. thuringiensis were nearly 50% less sensitive than exponential RNA polymerase activity. Inhibition patterns relating culture age at the time of RNA polymerase extraction to exotoxin inhibition suggested a direct correlation between diminishing exotoxin sensitivity and sporulation. Escherichia coli RNA polymerase could be made to mimic the B. thuringiensis exotoxin inhibition pattern by removal of sigma from the holoenzyme. After passage through phosphocellulose, exotoxin inhibition of the core polymerase was 30% less than the corresponding inhibition of E. coli holoenzyme. Heterologous enzyme reconstruction and assay were not possible due to loss of activity from the B. thuringiensis preparation during phosphocellulose chromatography, apparently from the removal of magnesium. In enzyme velocity studies, inhibition with exotoxin was noncompetitive with respect to the DNA template in the RNA polymerase reaction.
Presence and activity of the hexosemonophosphate shunt in a marine pennate chemoorganotrophic diatom, Nitzschia alba, clone Link 001
Authors: Linkins Arthur E.
Published: April 2010

A commonly occurring chemoorganotrophic diatom, Nitzschia alba, clone Link 001, stores primarily fatty acids and utilizes the hexose monophosphate shunt as a major pathway in hexose oxidation. The presence and activity of this pathway in exponentially growing N. alba was demonstrated by the growth on potassium gluconate as a sole carbon source, in vitro assay of 6-phosphogluconate dehydrogenase (EC 1.1.1.44), and in vivo radiorespirometric evaluation using [14C]-glucose or -gluconate. Radiorespirometry demonstrated that the hexose monophosphate and Embden–Meyerhoff–Parnas pathways account for 46 and 54% of hexose oxidation, respectively. The predominance of fatty acid storage plus the probable utilization of some C4–C5 hexose monophosphate intermediates in biosynthetic activities support the relatively high hexose monophosphate activity in these exponentially growing cells. Radiorespirometric values are supported by the absence of Entner–Doudoroff activity as determined by the lack of 2-keto-3-deoxy-6-phosphogluconate aldolase (EC 4.1.2.14) and 6-phosphogluconate dehydratase (EC 4.2.1.14) activity.
Actinomycètes antagonistes de champignons et n'affectant pas le Rhizobium meliloti
Authors: Antoun H. , Bordeleau L. M. , Gagnon C. , Lachance R. A.
Published: April 2010

The effects of 481 actinomycetes isolated from agricultural soils supporting good growth of alfalfa or clover on two efficient strains of Rhizobium meliloti A2 and S14 were studied. Strain A2 was inhibited by 28% of the isolates and strain S14 was inhibited by 31% of them. No significant difference was found between the resistance of both actinomycete strains. The effects of the 288 isolates not affecting R. meliloti on six fungi were also studied. The most sensitive fungus was Stemphylium sarcinaeforme inhibited by 20% of the isolates, while Fusarium culmorum was the most resistant fungus and was inhibited by only 6% of the isolates. Thirteen isolates inhibited four to six fungi. In an autoclaved greenhouse soil, isolate 181 which inhibited the six fungi tested significantly reduced the population of the phytopathogenic fungus F. oxysporum f. sp. medicaginis and eliminated the inhibitory effect showed by this fungus on strain A2 of R. meliloti.
Induction of autolysis in Bacillus subtilis by ochratoxin A
Authors: Singer U. , Röschenthaler R.
Published: April 2010

Ochratoxin A (OTA) added during the exponential growth phase at a concentration higher than 12 μg/ml caused autolysis of Bacillus subtilis. Optical density of cultures decreased, and at higher concentrations the cultures became sterile. Optimum OTA-induced lysis was about pH 5. At concentrations below 10 μg/ml, protein synthesis was inhibited more strongly than RNA synthesis. Cell wall synthesis was also strongly inhibited. A fraction extracted from the lysates had the property of a lysis inhibitor. The relevance of this fraction in respect to autolysis is discussed.
Sucrose uptake by Neisseria denitrificans
Authors: MacKenzie C. R. , McDonald I. J. , Johnson K. G.
Published: April 2010

Neisseria denitrificans possesses an inducible sucrose-uptake system. Sucrose is transported as the free sugar and is rapidly converted into polymerized material. Uptake is inhibited by glucose, cyanide, uncouplers of oxidative phosphorylation, and sulfydryl reagents. Glutamate serves as an energy source for uptake. The importance of this phenomenon in the oral environment is discussed.
Visual micromethod for assay of fungal growth
Authors: Kerbs Sharon , Hutton Robert D. , Hollister James W.
Published: April 2010

A visual micromethod for measuring antifungal effects on germination and growth is described. The antifungal agent griseofulvin and the fungus Trichophyton mentagrophytes were used as materials to compare the micromethod with a standard assay based on dry mycelial weight. The micromethod was more sensitive than the weight method in detecting the minimum inhibitory concentration of griseofulvin (0.18 and 0.35 μg/ml, respectively). At higher concentrations of griseofulvin (22.5 μg/ml), the micromethod measured minimal fungal growth that was undetectable on a weight basis. The micromethod showed that griseofulvin does not change the number of spores forming germ tubes. Progressively severe alterations in fungal morphology occured as the concentration of griseofulvin was increased from 0.09 to 22.5 μg/ml.
Incidence of the H2 group of plasmids in chloramphenicol-sensitive salmonella isolated in 1974 from clinical sources in Ontario
Authors: Taylor Diane E. , Shermer Mathew , Grant Robert B.
Published: April 2010

Chloramphenicol resistance in salmonella obtained from clinical sources in Ontario was previously found to be often mediated by R plasmids of the H2 incompatibility group. In the present study 40 salmonella strains resistant to one or more of kanamycin, streptomycin, sulfonamides, or tetracycline, but sensitive to chloramphenicol, were investigated to determine if they contained R plasmids. Self-transmissible plasmids were isolated from 17 of the strains, and 7 of these showed the bacteriophage inhibition and thermosensitive mechanism of transfer characteristic of H2 plasmids. Entry exclusion and incompatibility experiments confirmed their classification. The results demonstrate that in this population of salmonella, R plasmids of the H2 group are prevalent. Experiments with plasmid-specific phages indicate that the plasmids of this sample, which are not in the H2 group, do not belong to any of the F, I, N, P, or W incompatibility groups.
Glucose metabolism in Pycnoporus cinnabarinus
Authors: Hirono Emiko , Zancan Glaci T. , Amaral Déa
Published: April 2010

It was demonstrated by the measurement of enzyme activities and by radiorespirometric assays that the basidiomycete Pycnoporus cinnabarinus metabolizes glucose through the glycolytic pathway and the pentose phosphate cycle.
Efficacy of laboratory tests for the detection of enterotoxigenic Clostridium perfringens
Authors: Niilo L.
Published: April 2010

Nineteen Clostridium perfringens strains with positive erythemal and ligated intestinal loop reactions, and 22 strains with negative reactions, originating from food-poisoning cases, were tested comparatively using the fluorescent antibody (FA), reversed passive hemagglutination (RPHA), and immunodiffusion (ID) tests. All the biologically positive strains were detected by the three immunological tests used. The FA test detected five additional strains among the biologically negative group which did not react in RPHA or ID tests. Sporulating culture supernatant fluids, after 13 to 17 h of growth, were satisfactory for testing for the presence of enterotoxin by the RPHA and ID tests. The FA test was used on cell smears.
Action of some nitrofuran derivatives on glucose metabolism, ATP levels, and macromolecule synthesis in Escherichia coli
Authors: Lu Claudia , McCalla D. R.
Published: April 2010

In Escherichia coli B/r, nitrofurazone (NF; semicarbazone of 5-nitro-2-furaldehyde) at a concentration of 25 μg/ml inhibited nucleic acid synthesis as judged both by chemical analysis and by incorporation of [3H]thymidine and [3H]uracil into acid-insoluble material. This concentration of NF somewhat inhibited glucose and pyruvate oxidation and reduced the ATP levels in treated bacteria. A lower concentration (5 μg/ml), however, increased the ATP levels and stimulated the incorporation of [3H]uracil into acid-insoluble material. AF2 (2-(2-furyl)-3-(5-nitro-2-furyl) acrylamide) at 2.5 μg/ml (a concentration which inhibits [3H]thymidine incorporation to about the same extent as 25 μg/ml NF) inhibited net accumulation of both RNA and DNA but stimulated the incorporation of [3H]uracil. Treatment with AF2 also increased the ATP levels which in turn increased the conversion of [3H]uracil to UTP. AF2 somewhat inhibited the oxidation of glucose and pyruvate to CO2. Nitrofurantoin (25 μg/ml) and furazolidone (15 μg/ml) gave results similar to those with nitrofurazone, while N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) at 5 μg/ml was similar in its action to AF2. There was no direct correlation between inhibition of glucose oxidation or nucleic acid synthesis and killing.In strain NFR 207, a mutant which lacks the O2-insensitive nitrofuran-reductase I and is therefore unable to 'activate' nitrofurans, AF2 up to a concentration of at least 10 μg/ml had essentially no effect on glucose metabolism, ATP levels, incorporation of uracil and thymidine, or accumulation of RNA or DNA. In contrast, nitrofurazone produced effects in NFR 207 which were qualitatively similar to those in B/r but somewhat less extensive. These results indicate that all of the inhibitory effects of AF2 may be due to its metabolites while some of the effects of nitrofurazone are mediated by the unmetabolized drug.
Effect of pH on the antimicrobial activity of some triphenylmethane dyes
Authors: Moats W. A. , Maddox Jr. S. E.
Published: April 2010

Four common dyes were tested as inhibitors of four types of bacteria over the pH range 5.0–9.0. Inhibition of the gram-negative types, Salmonella anatum and Enterobacter aerogenes, was markedly affected by the pH of the medium. These organisms tolerated concentrations of crystal violet and ethyl violet about 100-fold higher at pH 5.0 than at pH 9.0. Above pH 7.0 brilliant green (BG) and malachite green (MG) were precipitated as their respective carbinols and lost their inhibitory properties with these two organisms. Two gram-positive types, Staphylococcus aureus and Bacillus cereus, were more sensitive to dyes and results were less affected by pH. The carbinol forms of MG and BG were nearly as inhibitory to these organisms as the ionized forms.
Antigenic variation and increase in pathogenicity in Pseudomonas aeruginosa as a result of growth on glucose or N-hexadecane as sole carbon source
Authors: Stinson Robert S. , Talburt D. E.
Published: April 2010

When Pseudomonas aeruginosa is grown on glucose as opposed to n-hexadecane as the sole carbon source, the antigenicity, virulence, and protein composition of the outer membrane are altered. The hydrocarbon-grown cells demonstrate a 3-log increase in virulence over the glucose-grown cells (in mice). There also appears to be an additional protein present in the outer membrane of the n-hexadecane-grown cells. This protein may contribute to the observed antigenic differences between the two cell types.
Studies on transfer RNA from mycobacteria
Authors: Deobagkar Dileep N. , Gopinathan K. P.
Published: April 2010

Active preparations of tRNA and aminoacyl-tRNA synthetases have been isolated from exponentially growing cells of Mycobacterium smegmatis and Mycobacterium tuberculosis H37Rv. Though the aminoacyl-tRNA synthetases of older cells retain their activity, the tRNAs seem to undergo modification and show poorer activity. The mycobacterial enzyme preparations catalyse homologous and heterologous aminoacylation between tRNA from the two species (M. smegmatis and M. tuberculosis H37Rv) or from Escherichia coli, with equal efficiency; tRNA samples from eukaryotic cells (yeast and rat liver) do not serve as substrates for the mycobacterial synthetases. The analytical separation of the different amino acid specific tRNAs from M. smegmatis resembles the pattern found in other bacteria. Purification of valine- (three species) and methionine-specific tRNAs (two species) to 70–80% purity has been accomplished by using column-chromatographic techniques. Of the two species of tRNAMet, one can be formylated in the presence of formyl tetrahydrofolate and the transformylase from mycobacteria.
Halobacterium vallismortis sp. nov. An amylolytic and carbohydrate-metabolizing, extremely halophilic bacterium
Authors: Gonzalez Carmen , Gutierrez Carmen , Ramirez C.
Published: April 2010

The extremely halophilic bacterium (formerly designated as strain J.F. 54) isolated from salt pools of the Death Valley. California, is a motile, Gram-negative, extremely pleomorphic organism, aerobe, and facultative anaerobe. A variety of carbohydrates are assimilated with or without acid production; soluble starch is hydrolyzed. The organism is not proteolytic; catalase, oxidase, and DNase reactions are positive; Tween 20 is slightly hydrolyzed, but Tweens 40, 60, and 80 are not. Nitrates are reduced to nitrites with gas production; nitrites are not reduced. Optimum growth temperature is 40 °C. Growth is inhibited by bacitracin and by novobiocin. The type strain J.F. 54 differs from described species of the genus Halobacterium and is assigned to a new species, Halobacterium vallismortis sp. nov.
Stable isotope fractionation by Clostridium pasteurianum. 2. Regulation of sulfite reductases by sulfur amino acids and their influence on sulfur isotope fractionation during SO32− and SO42− reduction
Authors: Laishley E. J. , Krouse H. R.
Published: April 2010

In addition to an assimilatory sulfite reductase, studies of cultures of Clostridium pasteurianum supplemented with methionine, cysteine, and 35SO42− provide evidence for another reductase which is induced by SO32−. This inducible reductase appears to be dissimilatory because of the copious sulfide production arising when the cells are grown on SO32−. Cysteine can repress the assimilatory sulfite reductase but does not affect the inducible reductase. During late logarithmic growth on 1 mM SO42− + 10 mM cysteine, derepression of the inducible reductase occurred along with increased sulfide production. The presence of 1 mM cysteine and (or) 1 mM methionine does not affect the inverse sulfur isotope effect for evolved H2S. However, 5 and 10 mM cysteine reduce the maximum δ34S value for released H2S from +40 to +10‰. A small conversion of cysteine to H2S by C. pasteurianum occurs, but only in the stationary phase.
Light microscopy observations of tetrazolium-reducing bacteria in the endorhizosphere of maize and other grasses in Brazil
Authors: Patriquin D. G. , Döbereiner J.
Published: April 2010

Roots of field-grown tropical maize, Panicum maximum Jacq. and Digitaria decumbens Stent., and of sorghum and wheat grown in monoxenic culture with the diazotroph Spirillum lipoferum (syn. Azospirillum spp.) were examined for tetrazolium-reducing bacteria following incubation of roots in a malate – phosphate buffer –2,3,5-triphenyltetrazolium chloride medium. Bacteria were observed between and in cells of the cortex, in intercellular spaces between the cortex and endodermis, in xylem cells, and in and between pith cells. In maize, colonization of the inner cortex and stele appears to occur in the absence of significant bacterial colonization or collapse of outerlying tissues. Bacteria in the stele remained viable after a 6-h treatment of roots with chloramine-t, indicating that the endodermis was intact. Infection of the inner cortex and stele appears to occur initially in branches, and then to spread longitudinally into main roots. Inter-and intra-cellular infections of the cortex were observed in monoxenic systems. Tetrazolium reduction and prominent crystal formation was not specific for diazotrophic bacteria, but S. lipoferum was isolated from surface-sterilized roots, and S. lipoferum-like organisms were observed in the endorhizosphere. A correlation of inner cortex and stele infections with the presence of branches appears to explain previous observations that excised roots of grasses exhibiting high nitrogenase activity are characteristically branched roots with an intact cortex.
Test for differentiation of M. tuberculosis and M. bovis from other Mycobacteria
Authors: Laszlo Adalbert , Eidus Leslie
Published: April 2010

A test is described for selective inhibition of Mycobacterium tuberculosis and M. bovis isolates in fluid medium. The method employs ρ-nitro-α-acetyl-amino-β-hydroxy-propiophenone (NAP) as an inhibitory agent for differentiation of mammalian tuberculosis strains from other Mycobacteria.
Isolation and characterization of actinophages of Thermoactinomyces and Micropolyspora
Authors: Kurup Viswanath P. , Heinzen Richard J.
Published: April 2010

Two new actinophages infecting thermophilic actinomycetes were isolated from iysogenic cultures of Thermoactinomyces Candidus and Micropolyspora faeni. The physiochemical properties, morphology, host range, electron microscopy, and immunology of the two phages, [Formula: see text] (ATCC 29680-B1) and [Formula: see text] (ATCC 29681-B1), are reported.
Characteristics of Thiobacillus thioparus and its thiocyanate assimilation
Authors: Katayama Yoko , Kuraishi Hiroshi
Published: April 2010

Thiocyanate-assimilating bacterium, TK 21, was isolated from activated sludge used for the treatment of thiocyanate contained in coke-oven liquor. This organism oxidized thiosulfate and elemental sulfur, causinga decrease of pH of the medium. These facts indicated that it belongs to the genus Thiobacillus. Potassium thiocyanate (0.5 g/ℓ) was completely assimilated during 60 h. Thiosulfate inhibited the assimilation of thiocyanate but elemental sulfur did not. This bacterium did not evolve cyanide as its oxidation product after the decomposition of thiocyanate. The isolated bacterium was identified as Thiobacillus thioparus. Examination of the composition of cellular fatty acid of three strains of T. thioparus showed that they possessed 3-hydroxy fatty acids of C10 and C12; saturated straight chains of C10, C12, C15, C16, C17, and C18; mono-unsaturated straight chains of C16 and C18; and cyclopropane acid of C17.
Inhibition of enzyme induction in Pseudomonas aeruginosa by exogenous nucleotides
Authors: Kight-Olliff Lynda C. , Fitzgerald J. W.
Published: April 2010

Alkylsulfatase induction in resting cell suspensions of P. aeruginosa was inhibited by exogenously supplied adenosine or by ATP (2 mM). Adenine phosphate had no effect while AMP or ADP caused a slight stimulation of induction. The inhibitory effect of ATP required the presence of added Mg2+, was not reversed by cyclic-AMP(2 mM), and was independent of the nature of the inducer. Of a number of other nucleoside triphosphates tested, only UTP (2 mM) acted as an inhibitor of induction. These nucleotides at external concentrations of 6 mM also inhibited alkylsulfatase induction in actively growing cells.
Difference in generation times for mother and daughter cells in yeasts
Authors: Flegel T. W.
Published: April 2010

Fruitless attempts to synchronize haploid yeast cells from the Phragmobasidiomycete Sirobasidium magnum led to the discovery that the mother and daughter cells (MDC) had greatly different generation times. Time-lapse photographic sequences of budding showed that the mean generation time for daughter cells was more than three times greater than that for mother cells. This growth characteristic could be determined by a spot check of the microcolony pattern on agar. Using such a check, yeast strains of Rhodotorula (Rhodosporidium) and Cryptococcus that were tested demonstrated relative MDC equivalence while those of Sporobolomyces, Bullera, and Tremella showed MDC non-equivalence in varying degrees.
The microbial degradation of cyclohexanecarboxylic acid by a β-oxidation pathway with simultaneous induction to the utilization of benzoate
Authors: Blakley E. R.
Published: April 2010

The metabolism of cyclohexanecarboxylic acid by a bacterium, designated PRL W19, follows a pathway involving β-oxidation of coenzyme A intermediates analogous to the classical oxidation of fatty acids. The organism appears to have the property for the constitutive metabolism of caproic acid, and cell extracts contain high levels of the enzymes required for the functioning of the fatty acid cycle. However, the metabolism of cyclohexanecarboxylic acid requires induction by growth or incubation with an appropriate substrate. Extracts of induced cells contain several enzyme activities which are synthesized in response to the induction process. These enzymes include cyclohexanecarboxyl-CoA synthetase, cyclohexanecarboxyl-CoA dehydrogenase, 1-cyclohexenecarboxyl-CoA hydratase, and trans-2-hydroxycyclohexanecarboxyl-CoA dehydrogenase. A characteristic feature of this organism is that it becomes induced for the metabolism of benzoate and catechol during growth on cyclohexanecarboxylic acid, but benzoate does not appear to be an obligatory intermediate in the metabolism of cyclohexanecarboxylic acid.
Lipopolysaccharides of the motile aeromonads; core oligosaccharide analysis as an aid to taxonomic classification
Authors: Shaw Derek H. , Hodder H. J.
Published: April 2010

Twelve motile Aeromonas strains have been examined with respect to the hexose and heptose monosaccharide residues present in the core region of their cell wall lipopolysaccharides. These strains were divided into three distinctly separate groups on the basis of the various combinations of hexose and heptose residues. The assignment of a strain to any one of the three groups furnishes a distribution which is substantially the same as that recently reported in a computer-based numerical analysis. All strains tested which were previously named A. liquefaciens fall into the same group.
The effect of compounds which degrade hydrogen peroxide on the enumeration of heat-stressed cells of Salmonella senftenberg
Authors: Rayman M. K. , Aris B. , Derea H. B. El
Published: April 2010

Greater than 90% of heat-stressed cells of Salmonella senftenberg failed to grow on trypticase soy agar. Adding to this medium compounds which are capable of degrading hydrogen peroxide allowed growth of the heat-injured cells. These compounds did not stimulate growth of heated cells of Streptococcus faecinin. an organism which does not possess catalase.
Antibiotic resistance patterns of fecal coliforms isolated from domestic sewage before and after treatment in an aerobic lagoon
Authors: Bell R. B.
Published: April 2010

The resistance of 260 strains of fecal coliforms, isolated from raw domestic sewage and aerobic lagoon effluent, to ampicillin, aureomycin. Chloromycetin, gentamicin, streptomycin, sulfadiazine, and tetracycline, was determined. Aerobic lagoon treatment produced a 20-fold reduction in the fecal coliform numbers. No statistically significant difference in antibiotic resistance was observed between the fecal coliforms found in raw sewage and in lagoon effluent despite a trend towards the loss of resistance in the latter. Antibiotic resistance, either single or multiple, did not contribute to, or detract from, bacterial survival in the aerobic lagoon. Of the isolates, 15% showed resistance to two or more antibiotics.
Germination and outgrowth of Schizosaccharomyces pombe ascospores isolated by Urografin density gradient centrifugation
Authors: Nishi Kayoko , Shimoda Chikashi , Hayashibe Masaya
Published: April 2010

A simple method for the isolation of single ascospores of the fission yeast Schizosaccharomyces pombe was examined. Single spores in the 7-day-old sporulating culture of a homothallic strain were separated from remaining vegetative cells by isopycnic centrifugation in the linear gradient from 10 to 60% of Urografin solution at 700 × g for 20 min. Protein content of isolated spores was very low as compared with that of vegetative cells. The isolated spores germinated through the following steps when cultured in a liquid medium at 25–35 °C; loss of refractility (darkening) under a phase-contrast microscope, spherical growth (swelling), emergence of germ tubes, elongation of germ tubes, cell plate formation, and cell separation. The absorbance at 650 nm of the spore suspension initially decreased, accompanied by darkening of spores, and then increased with spherical growth. The germination rate of isolated spores reached almost 100%.
Growth characteristics of three bacterial isolates from an arctic soil
Authors: Nelson Louise M. , Parkinson D.
Published: April 2010

Three bacterial isolates, a Pseudomonas sp., a Bacillus sp., and an Arthrobacter sp., commonly isolated from a hummocky sedge–moss meadow at Devon Island, N.W.T., Canada, were selected for further taxonomic characterization and for a study of the effects of temperature and limiting carbon source on growth. Pseudomonas M216 resembled P. putida and Bacillus M 153, B. carotarum. Arthrobacter M51 had growth-factor requirements which were more complex than those of any named species of that genus. The temperature ranges of growth indicated that Pseudomonas M216 and Arthrobacter M51 were psychrotrophic while Bacillus M153 was mesophilic. Growth in batch culture at limiting glucose concentrations enabled the calculation of Ks and Y values for each isolate. These were similar to those obtained for other organisms and Pseudomonas M216 and Bacillus M153 showed a high affinity for glucose. The nutritional versatility of Arthrobacter M51 and its ability to grow at low temperatures and the high growth rates and affinity of Pseudomonas M216 for low substrate concentrations may account for their competitive abilities in the natural environment, while the inability of Bacillus M153 to grow at low temperatures may limit its activity in tundra soils.
A Zoogloea sp. associated with blooms of Anabaena flos-aquae
Authors: Caldwell Douglas E. , Caldwell Sarah J.
Published: April 2010

Bacteria were found attached to the heterocysts of Aphanizomenon flos-aquae and embedded within the mucilage of both Anabaena flos-aquae and Microcystis aeruginosa in freshwater plankton. Electron microscopy of thin sections preceding the peak of an Anabaena flos-aquae bloom showed that the density of bacterial cells was 7.4 × 105 cells/ml in the planktonic macroenvironment and 2.6 × 1011 cells/ml within the microenvironment of cyanobacterial mucilage. The bacteria occurred in aggregates and isolation required that these be dispersed by homogenizing at 50 000 rpm with glass beads. This procedure yielded a single bacterial isolate from blooms of Anabaena flos-aquae during 2 consecutive years. The isolate was flagellated, catalase- and oxidase-positive, Gram-negative, and rod-shaped to pleomorphic. Observation that the isolate required a pH greater than 8 for consistent growth, could not grow alone on liquid media but could grow alone on the corresponding solid media, could grow in liquid media only in the presence of Anabaena, formed tough mucilagenous colonies on solid media only in the presence of Anabaena extract, and rapidly assimilated but did not respire extracellular 14C-labelled organic matter produced by Anabaena suggested that the occurrence of the bacterium in cyanobacterial mucilage was not coincidental but reflected an obligatory bacterial requirement for the biological or physicochemical microenvironment of the mucilage. The bacterial isolate occurred in three growth forms. Either as a planktonic swarmer cell (which showed a positive chemotactic response to the cyanobacterium) embedded in cyanobacterial mucilage, or embedded in its own mucilage derived, in part, from a low molecular weight (below 1300) carbohydrate secreted by the cyanobacterium. These cultural, biochemical, and ecological characteristics suggest that the isolate is a new species in the genus Zoogloea and of potential importance in phytoplankton ecology.