bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of sugars and polyols on basidiocarp formation in a phosphoglucose isomerase mutant of Coprinus cinereus
Authors: Nyunoya Hiroshi , Takemaru Tsuneo , Ishikawa Tatsuo
Published: May 2010

Several biochemical properties of a mutant deficient in phosphoglucose isomerase (pgi) of Coprinus cinereus were examined in connection with its ability to produce basidiocarps. Mycelium of the pgi mutant accumulated glucose-6-phosphate and showed higher glucose-6-phosphate dehydrogenase activity than wild type. A conventional fruiting medium did not support basidiocarp formation by the homozygous dikaryon pgi/pgi, but the addition of a reduced amount of glucose plus a compensatory amount of fructose to the culture medium resulted in partial recovery of fruiting ability. This modification of the culture medium decreased the intracellular glucose-6-phosphate to almost the same level as in the wild type. The addition of polyols such as mannitol resulted in complete recovery of fruiting ability by the dikaryon pgi/pgi without affecting the level of glucose-6-phosphate. Mycelium of the mutant showed an elevated activity of NAD-linked polyol dehydrogenase and an elevated intracellular NAD level, irrespective of whether the mycelium was grown in the presence or absence of polyol.
Inhibition of anion transport in human erythrocytes by pilated Neisseria gonorrhoeae
Authors: Wiseman G. M. , Martin C. F. , McNicol P. J.
Published: May 2010

Pilated gonococci added to human erythrocytes apparently bind to polypeptide band 3 and inhibit chloride–bicarbonate exchange across the membrane in contrast with nonpilated organisms. Known covalent inhibitors of anion transport (4,4′-diisothiocyano-2,2′-disulphonic acid stilbene and α-cyano-4-hydroxycinnamic acid) inhibit chloride efflux from erythrocytes and also reduce hemagglutination titres, strongly suggesting that band 3 is the major host-cell receptor involved in all interaction between gonococci and erythrocytes. In studies of other cell species, however, band 3 prepared from human erythrocytes inhibited adherence of pilated gonococci to human foreskin and HeLa cells, but was without effect in human buccal, Vero, and mouse L cells.
Isolation of nonlysogenic bacteria from λ-lysogenized strains using antibiotic-resistant phage
Authors: Kordyum V. A. , Chernykh S. I. , Medvedeva I. Y.
Published: May 2010

A simple and efficient method for obtaining nonlysogenic bacteria from λ-lysogenized strains using phage with an inserted antibiotic-resistant plasmid is described. When the lysogenic culture is infected with antibiotic-resistant phage, single non-lysogenic cells are lysogenized, isolated on selective medium, and cured of phage during incubation at 37 °C.
The role of Thiobacillus albertis glycocalyx in the adhesion of cells to elemental sulfur
Authors: Bryant R. D. , Costerton J. W. , Laishley E. J.
Published: May 2010

Thiobacillus albertis, a newly characterized acidophilic Thiobacillus sp., was found not to be dependent on physiological conditions such as pH, cellular energy, or peripheral cell envelope sulfhydryl groups for attachment to elemental sulfur (S0). Heat-killed cells or those pretreated with sulfhydryl reagents (iodoacetate or iodoacetamide) were able to adhere to S0 in comparable numbers as assayed by epifluorescence microscopy. In addition, iodoacetate and iodoacetamide were found to be bactericidal, the former more potent than the latter. Sodium lauryl sulfate was found to cause nearly complete detachment of T. albertis cells from glass slides implicating its glycocalyx for this cell–glass attachment. In addition scanning electron microscopy visually revealed T. albertis cellular adhesion to S0 was due to the organism's threadlike glycocalyx material interacting with the sulfur surface. It was concluded that T. albertis glycocalyx plays an important role in the attachment to solid surfaces (glass or S0). In addition T. albertis was shown to colonize S0 surfaces by microcolonies.
Virological examination of drinking water: a Canadian collaborative study
Authors: Payment Pierre , Trudel Michel , Sattar S.A. , Springthorpe V. S. , Subrahmanyan T. P. , Gregory B. E. , Vajdic A. H. , Blaskovic P. , Guglielmi I. J. , Kudrewko O.
Published: May 2010

A collaborative virological survey of drinking water was initiated in three major Canadian urban areas, Montreal, Ottawa, and Toronto. In each selected area, three water purification plants were sampled monthly for up to 18 months. The total population served by all nine plants was about 1 500 000. Samples of raw (100 L) and treated (1000 L) water were examined by virus concentration procedures based on adsorption–elution. Sample concentrates were assayed for cytopathic viruses on BS-C-1 cells and the results were expressed as the most probable number of cytopathic units (MPNCU). Viruses were detected in 57% (0–15.35 MPNCU/L) of the raw water samples from Montreal, 37% (0–46.0 MPNCU/L) in Ottawa, and 33% (0–4.91 MPNCU/L) in Toronto. The majority of isolates were reoviruses, but picornaviruses were also found. All finished waters (177 samples) met bacteriological, turbidity, and residual chlorine standards and were free of detectable viruses.
Specificity of subcellular distribution of alkaline phosphatase in Bacillus licheniformis 749/C
Authors: Ghosh Arati , Vallespir Steve , Ghosh B. K.
Published: May 2010

The objective of this investigation was to examine the in vivo characteristics of binding sites for alkaline phosphatase in Bacillus licheniformis cell surface. An attempt was made to correlate the results from several experimental approaches, namely (i) cell fractionation; (ii) ultrastructural cytochemistry; (iii) MgCl2 extraction and sodium dodecyl sulphate – polyacrylamide electrophoresis of the extracted material; (iv) labelling with 125I-labelled diazonium salt to determine the subcellular origin of MgCl2-extracted material. Results show that 40% of the alkaline phosphatase was bound to the plasma membrane, 35% to the cell wall, and 15% was free in the cytosol. The enzyme was present as aggregates in a few discrete sites in the membrane, wall, and cytoplasm. The membrane enzyme was associated with the inside surface. A few aggregates were enclosed in single-layered vesicles which appeared to protrude through the cell wall. The material extracted with magnesium salt consisted of 8–10 proteins including alkaline phosphatase. The majority of the proteins extracted by MgCl2 originated from the outside half of the plasma membrane, whereas, only a few, including alkaline phosphatase, came from the inside half of the plasma membrane. All of these proteins may have formed a complex which was removed by MgCl2 extraction. Patch formation in the membrane indicated specific aggregation of intramembrane proteins after MgCl2 treatment.
Extracellular enzyme production by Rhizopus and Mucor species on solid media
Authors: Thompson D. P. , Eribo Broderick E.
Published: May 2010

Solid media were employed to determine the presence and absence of extracellular enzyme production by two genera of fruit-rot fungi, Rhizopus and Mucor. The results of this investigation revealed that phosphatase was released into the cultural medium by all the fungi examined; however, only R. oryzae, R. tritici, M. mucedo, and M. piriformis showed the possibility of being high producers of the enzyme. Protease, urease, ribonuclease, pectate lyase, and polygalacturonase, at varying levels of activity, were detected, in the majority of the fungi, in the cultural medium.
Isolation and partial characterization of a human adenovirus type 4 temperature-sensitive mutant (Mastadenovirus h 4 tsl)
Authors: Mofford Linda M. , Marusyk R. G.
Published: May 2010

A random selection procedure was used to isolate a temperature-sensitive (ts) mutant of human adenovirus type 4 (Mastadenovirus h 4 tsl) from nitrous acid mutagenized virus stock. The mutant displayed restricted growth at the nonpermissive temperature of 39 °C. Analysis of the mutant grown at 39 °C, by two-dimensional immunoelectrophoretic analysis, showed the mutant to be defective in the expression of the penton base and fibre structural components. The mutant was, however, capable of synthesizing immunologically reactive hexon components. Temperature-shift experiments revealed detectable fibre and penton to be present following shift-down from 39 to 32 °C. Time-sequence analysis of shift-down experiments suggested a possible defect in processing of the components, as indicated by an increase of immunologically detectable penton base. The ability of the mutant to assemble viruslike particles at 39 °C was confirmed by electron microscopy. Though the particles assembled appeared as mature virions, crystalline arrays of packed particles were less in number and somewhat smaller in size than those observed at 32 °C.
Evidence for the involvement of the soil microbiota in the exclusion of Fusarium from coniferous forest soils
Authors: Schisler David A. , Linderman R. G.
Published: May 2010

Fusarium was recovered from only 1 of 14 Pacific Northwest coniferous forest soils but from all 7 nursery soils tested. Assays using high concentrations of Fusarium oxysporum macroconidia added to soil determined that forest soils stimulate macroconidial germination [Formula: see text] often followed by germ-tube lysis or the formation of stunted chlamydospores, while nursery soils support little macroconidial germination [Formula: see text]. Treatment of forest soils with aerated steam (minimum of 45 °C for 30 min), radiation, or propylene oxide reduced the amount of germination in forest soils, suggesting that the forest soil microbiota is involved in the stimulation of macroconidial germination. Bacteria isolated from F. oxysporum hyphae placed in forest, field, or nursery soils on nylon screens did not significantly influence germ-tube lysis when combined with macroconidia in a nutrient broth. Chemical, physical, and nutritional properties of forest soils likely affect the capacity of the forest soil microbiota to influence Fusarium macroconidial germination and germ-tube lysis.
A histochemical study of sclerotia of Botrytis cinerea and Botrytis fabae
Authors: Backhouse D. , Willetts H. J.
Published: May 2010

Histochemical techniques were used to determine the nature and distribution of nutrient reserves and other materials in sclerotia of two isolates of Botrytis cinerea and one isolate of B. fabae. All isolates showed similar staining reactions. Hyphal walls contained chitin and β-glucans, including β-1,3-glucans, while rind cell walls also contained a melanic pigment. Medullary hyphae were surrounded by a continuous matrix of β-glucans. The intracellular nutrient reserves found were protein, glycogen, polyphosphate, and lipid.
Conversion of pretreated lignocellulosic substrates to ethanol by Clostridium thermocellum in mono- and co-culture with Clostridium thermosaccharolyticum and Clostridium thermohydrosulphuricum
Authors: Saddler J. N. , Chan M. K.-H.
Published: May 2010

Two strains of Clostridium thermocellum, NRCC 2688 and ATCC 31924, demonstrated different product yields and cellulase activities when grown on solka floc, steam-exploded aspen wood, and wheat straw fractions. Highest ethanol values were obtained with 1% substrate concentrations, while higher substrate concentrations resulted in a decrease in ethanol production. Strain NRCC 2688 grew on solka floc and steam-exploded fractions which had been water and alkali extracted, resulting in the accumulation of glucose in the medium. Strain ATCC 31924 grew on all of the pretreated lignocellulosic fractions, accumulated no glucose, and produced the highest amounts of ethanol (2.9 mg/mL) and endoglucanase activity (6.2 IU/mL) after growth on 1% solka floc. When strain NRCC 2688 was grown in co-culture with C. thermosaccharolyticum or C. thermohydrosulphuricum, higher ethanol values were obtained (1.8–2.2 mg/mL) and virtually no reducing sugars were detected in the medium. Co-culturing the two pentose-fermenting anaerobes with C. thermocellum ATCC 31924, however, did not enhance ethanol production, although little reducing sugar was detected in the medium. The composition of the lignocellulosic substrate was shown to influence the ethanol yields of the different mono- and co-cultures.
Preliminary characterization of inhibitors of Neisseria gonorrhoeae produced in vitro by Eubacterium limosum
Authors: Morin A. , Bisaillon J.-G. , Beaudet R. , Sylvestre M. , Saheb S. A. , Leduc D.
Published: May 2010

Among anaerobic bacteria normally found in the urogenital flora, Eubacterium limosum was found to inhibit the in vitro growth of Neisseria gonorrhoeae. The antigonococcal activity produced by E. limosum was soluble in methanol and in a chloroform–methanol mixture (30:70). The fraction soluble in chloroform–methanol (30:70) yielded eight absorbance peaks when chromatographed on Bio-Gel P-2 and the inhibitory activity was found in the first two peaks. This activity was not adsorbed on DEAE Sephacel and was eluted with distilled water in a peak considered as peak 1, on which preliminary characterization was done. The inhibitory activity of peak 1 was found to be heat and pH resistant and not susceptible to proteases, lipase, or amylases. When peak 1 was chromatographed on cellulose paper using a butanol – acetic acid (4:1) solvent system, eight different spots were detected upon spraying the paper with ninhydrin. No spot was detected with anthrone, bromothymol, nor Sudan black reagents used for the detection of carbohydrates and lipids. Based on sodium dodecyl sulfate – urea polyacrylamide gel electrophoresis and gel chromatography on Sephadex G-25, peak 1 appeared either as a diffuse band and as a single peak, respectively. The molecular weight of the inhibitory complex was estimated to be 2400. All these results suggest that the antigonococcal activity produced by E. limosum is composed of more than one low molecular weight amino compound.
A catabolite-resistance mutation is localized in the rpo operon of Bacillus subtilis
Authors: Sun Dongxu , Takahashi I.
Published: May 2010

By transformation analysis, a mutation (crsE1), which makes Bacillus subtilis cells able to sporulate in the presence of relatively high concentrations of glucose and other carbon sources, was mapped in the rpoBC operon. The effect of crsE1 mutation can be suppressed by another mutation in the same operon, rfm11, which confers resistance to rifamycin. Mutants carrying stv or std mutations, which are also located in the rpoBC operon, showed partial resistance to catabolites in sporulation. It appears therefore that a change in the structure or synthesis of RNA polymerase may alter the response of cells to the inhibitory effect of catabolites on sporulation.
Directed biosynthesis of novel derivatives of echinomycin by Streptomyces echinatus. I. Effect of exogenous analogues of quinoxaline-2-carboxylic acid on the fermentation
Authors: Gauvreau D. , Waring M. J.
Published: May 2010

Streptomyces echinatus A8331 cultured on a maltose minimal salts medium normally produces a single antibiotic, echinomycin (quinomycin A), containing two quinoxaline-2-carbonyl chromophores. Echinomycin is powerfully active against experimental tumours and can be assayed by its activity against Gram-positive bacteria. Grown in the presence of aromatic carboxylic acids related to quinoxaline, S. echinatus responds in favourable circumstances by incorporating the added material into analogues of the natural antibiotic having replacement chromophores. Both mono- and bis-substituted derivatives are formed. With quinoline-2-carboxylic acid as precursor, large quantities of analogues are produced, and the time course of synthesis, extraction, purification, assay, and characterization of the derivatives are described. Twenty-two other aromatic acids have been tested as potential substrates for antibiotic analogue biosynthesis. Half of them did not significantly affect growth and echinomycin production. Five appeared to stimulate antibiotic synthesis, while the remainder proved inhibitory. New biologically active antibiotics were detected in cultures supplemented with 7-chloroquinoxaline-2-carboxylic acid; 1,2,4-benzo-as-triazine-3-carboxylic acid; thieno[3,2-b]pyridine-5-carboxylic acid; and 6-methylquinoline-2-carboxylic acid.
Morphological examination of cell surface structures of enterotoxigenic strains of Escherichia coli
Authors: Chan R. , Acres S. D. , Costerton J. W.
Published: May 2010

The very fine sinuous K99 pili of enterotoxigenic strains of Escherichia coli can be visualized in shadowed and in negatively stained preparations, especially if the amorphous K30 glycocalyx is not produced, but these very delicate structures cannot be directly resolved in sectioned material. The K99 pili can, however, be thickened by the nonspecific accretion of K30 glycocalyx material, during its condensation as a result of dehydration, to the point where it can be resolved in sectioned material. This visualization is enhanced if the accreted and condensed glycocalyx is stained with ruthenium red. Alternatively and additionally, the K99 pilus can be thickened by the specific accretion of monoclonal antibodies so that it is made visible in sectioned material. The condensation of the hydrated K30 antigen glycocalyx of enterotoxigenic strains of Escherichia coli during dehydration can be prevented by stabilization using specific antibodies so that this capsular glycocalyx structure is identified in sectioned material and is seen in its correct distribution and dimensions. These methods allow the identification and visualization of bacterial surface structures, both in vitro and in vivo, and they provide a useful means of assessing the presence and distribution of these structures at all stages of the bacterial disease and a possible means of assessing their roles in the pathogenic process.
In vivo proteins of defective interfering particles of poliovirus
Authors: Tershak Daniel R.
Published: May 2010

DX particles of poliovirus are deletion mutants that do not induce synthesis of capsid proteins or the precursor of capsid proteins (NCVPla) during infection. However, cells infected with DX particles synthesize two proteins, p68 and p25, that are not detected during growth of standard virus, and a protein of 27 000 (p27) which is comparable in molecular weight to VP3. Peptide maps of these proteins were obtained by partial digestion with Staphylococcus aureus V8 protease and elastase. The peptide map of p68 corresponded approximately 70% with the peptide map of NCVPla, and antiserum against virions reacted with p68. These data suggest that p68 is a large fragment of NCVPla. Digestion of purified structural proteins VP1, VP2, and VP3 yielded distinct peptide maps, but p25 was resistant to both V8 protease and elastase and did not react noticeably with anticapsid antibody. Peptide maps obtained for in vivo viral proteins migrating with a molecular weight of 27 000 were complex, indicating the presence of at least two and possibly three proteins. Cells infected with standard gs and gr viruses produced authentic VP3, but cells infected with defective interfering particles did not. However, one gr variant of standard virus contained a mutation in structural protein VP2.
Specific cross-protective antigonococcal immunity in the murine genital tract
Authors: Corbeil L. B. , Wunderlich A. C. , Lyons J. M. , Braude A. I.
Published: May 2010

Specific acquired immunity to gonococci was studied in systemically immunized mice, challenged with 107 gonococci by intrauterine inoculation. Protection after intraperitoneal immunization was monitored by vaginal cultures taken 24 h post-challenge, since events during the first 24 h postexposure to gonococci are crucial in determining the outcome of infection. Mice were protected against gonococcal challenge by two inoculations with either live or boiled gonococci given 4 weeks apart, whereas immunization with one inoculation did not protect against challenge 1 week later. Protection was correlated with high titers of IgG antibody in serum after two immunizations, but not with the high titers of serum IgM antibody found after the one immunization. IgG antibodies, but not IgM antibodies, were shown to pass into genital secretions. Protection could be passively transferred by serum with high titers of antibody. Of most practical importance was the finding that not only were heat-stable antigens protective, but also heterologous protection resulted after immunization with three strains differing in source (disseminated gonococcal infection versus gonorrhea), opacity–transparency characteristics, and serum sensitivity. The data indicate that IgG antibodies resulting from systemic immunization with heat-stable antigens may be able to provide cross-protection immunity against gonorrhea.
Rapid detection of methicillin-resistant staphylococci with the MS-2 system
Authors: Flournoy D. J. , Qadri S. M. Hussain , Johnson W. Steve
Published: May 2010

The ability of the updated Abbott MS-2 system to detect methicillin-resistant Staphylococcus aureus (MRSA) was compared with disk agar diffusion and broth microdilution. Of the 87 MRSA isolates tested, the MS-2 system correctly detected 85 (97.7%) in 5 h. Seventy-two of the isolates were detected by disk agar diffusion within 24 h, and 15 more by 48 h. Broth microdilution detected 71 MRSA by 24 h of incubation and 11 more by 48 h. The updated MS-2 system yielded reliable results that were highly comparable with the standard techniques.
Structure and properties of the phosphoenolpyruvate: glucose phosphotransferase system of oral streptococci
Authors: Vadeboncoeur Christian
Published: May 2010

The presence of three distinct enzymes II that catalysed the phosphoenolpyruvate-dependent phosphorylation of glucose, fructose, and mannose was established in membranes of glucose-grown cells of Streptococcus salivarius 25975 and various strains of Streptococcus mutans. The enzyme II mannose phosphorylated mainly mannose, glucose, and 2-deoxyglucose, and the enzyme II glucose phosphorylated glucose, α-methylglucoside, and 2-deoxyglucose. The phosphoenolpyruvate-dependent phosphorylation of glucose and α-methylglucoside by isolated membrane of wild-type or EII mannose negative mutant cells did not require the presence of any soluble protein other than enzyme I and the phosphocarrier protein HPr. This result suggested that oral streptococci do not possess a soluble factor III glucose. The enzyme II activities varied as a function of the growth sugar but were not coordinately regulated. The variation elicited by specific sugars was not identical for all the strains tested. Nevertheless, in the case of the S. mutans strains, growth at the expense of lactose always caused a significant decrease in the level of enzyme II activities. Finally, experiments conducted with EII mannose negative mutants and also with a pseudorevertant isolated from one of these mutants indicated that the preferential utilization of glucose over lactose by cells growing in mixtures depended on the presence of the EII mannose, but not on glucose-derived metabolites.
The effect of free-living nematodes and compost moisture on growth and yield in Agaricus brunnescens
Authors: Kaufman T. D. , Lukezic F. L. , Bloom J. R.
Published: May 2010

The responses of four mushroom cultivars ('PSU-310,' 'PSU-324,' 'PSU-348,' and 'PSU-344') exposed to free-living nematode infestations were compared in two experiments by quantitatively determining the amount of mycelium in compost samples using a laccase assay technique. The amount of mycelial production for cultivars 'PSU-310,' 'PSU-324,' and 'PSU-348' in the control treatments of both studies was similar. While cultivar 'PSU-344' produced less mycelium as shown by laccase production, mycelial production was greatly reduced for all four cultivars exposed to nematode infestations in a high-moisture compost (78%) over the duration of the experiment. The initial compost moisture is implicated as a critical factor influencing the potential damage caused by nematode infestations.
Isolation and characterization of two bacteriophages of a stem-nodulating Rhizobium strain from Sesbania rostrata
Authors: Lajudie Philippe de , Bogusz Didier
Published: May 2010

Two rhizobiophages, RS1 and RS2, were isolated in Senegal from a soil sample and dry stem nodules of Sesbania rostrata, a tropical legume that is infected by two categories of Rhizobium strains: "stem strains," which nodulate both roots and stems (type strain, ORS571), and "root strains," which induce effective nodules only on roots. Both phages were found to have a host range restricted to ORS571; all root strains were found to be resistant. By electron microscopy, phage RS1 showed an hexagonal head 63 nm wide and a tail 87 nm long; phage RS2 revealed an hexagonal head 60 nm wide. Characterization of phage growth cycle by one-step growth experiments showed that the latent period was ca. 75 min for RS1 and ca. 4 h for RS2, that the rise period lasted ca. 2 h for both RS1 and RS2, and that the average burst size was ca. 100 for RS1 and 130 for RS2. Temperature denaturation occurred at 60–65 °C (RS1) and 45–50 °C (RS2). Serum neutralization tests revealed that the phages were not serologically related. In contrast to RS1, RS2 appeared to be temperate, since stable lysogens were isolated.
Glucose metabolism of Treponema bryantii, an anaerobic rumen spirochete
Authors: Stanton Thad B.
Published: May 2010

The pathway of glucose metabolism by Treponema bryantii, an obligately anaerobic spirochete isolated from bovine rumen contents, was studied. Washed cell suspensions of the spirochete consumed glucose and CO2 and produced equimolar amounts of acetate, formate, and succinate. Carbon dioxide was essential for glucose metabolism. Determination of radioactivity in products formed from 14C-labelled glucose and NaH14CO3 and assays of enzyme activities in cell-free extracts were used to determine the pathway of glucose metabolism. Treponema bryantii catabolized glucose to pyruvate via the Embden–Meyerhof–Parnas pathway. The spirochete used a coliform pyruvate–formate lyase to degrade pyruvate and produce formate and acetate. Succinate was formed by a pathway which involved the condensation of CO2 with pyruvate (or phospho(enol)pyruvate) formed from the breakdown of glucose.
Pyruvate carboxylase from Thiobacillus novellus: properties and possible function
Authors: Charles A. M. , Willer D. W.
Published: May 2010

Pyruvate carboxylase (EC 6.4.1.1) from Thiobacillus novellus (ATCC 8093) was highly purified and found to have a pH optimum of 7.6, a temperature optimum of 25–35 °C, and a requirement for a monovalent and a divalent cation, as well as a CoA derivative, for maximum activity. These were best served by K+, Mg2+, and acetyl-CoA. Km values for pyruvate, ATP, HCO3− and Mg2+ were 0.25, 0.04, 0.27, and 0.44 mM, respectively. Initial velocity plots of increasing acetyl-CoA concentrations gave a sigmoidal curve with Ka of 4.2 μM, and Hill coefficients of 2.2. Plots of fixed acetyl-CoA concentrations against varying concentrations of pyruvate, ATP, or CO2 all gave rectangular hyperbolae. Apart from end products, only hydroxypyruvic acid was found to be inhibitory. The enzyme was very sensitive to mercurials. This enzyme is not believed to serve an anaplerotic function, because of the simultaneous presence of the highly regulated phosphoenolpyruvate carboxylase in the organism. Instead, it may function either to supply oxaloacetate to the citrate cycle or as part of the system that provides reduced NADP+.
Protoplast fusion within the genus Kluyveromyces van der Walt emend. van der Walt
Authors: Johannsen Elzbieta , Halland Linda , Opperman Annette
Published: May 2010

Fusion experiments, involving protoplasts of selected hybridizing and nonhybridizing Kluyveromyces strains, are reported. The results obtained indicate that prototrophic fusion products were recovered from all 54 crosses involving the protoplasts of hybridizing strains. These products showed varying degrees of stability. Although two different methods of protoplast preparation and protoplast fusion were employed, only 7 out of 32 fusion experiments involving nonhybridizing strains yielded prototrophic fusion products. All these fusion products proved to be unstable after a single passage through a complete medium. reverting directly to the parental strains.
Electron transport in Paracoccus halodenitrificans and the role of Ubiquinone
Authors: Hochstein Lawrence I. , Cronin Sonja E.
Published: May 2010

The membrane-bound NADH oxidase of Paracoccus halodenitrificans was inhibited by dicoumarol, 2-n-heptyl-4-hydroxyquinoline-N-oxide (HQNO), and exposure to ultraviolet light (at 366 nm). When the membranes were extracted with n-pentane, NADH oxidase activity was lost. Partial restoration was achieved by adding the ubiquinone fraction extracted from the membranes. Succinate oxidation was not inhibited by dicoumarol or HQNO, but was affected by ultraviolet irradiation or n-pentane extraction. However, the addition of the ubiquinone fraction to the membranes extracted with n-pentane did not restore enzyme activity. These observations suggested that NADH and succinate were not oxidized through a common ubiquinone pool.
Quantitative changes in fungal colony-forming units in the surface microlayers of two freshwater ponds
Authors: Maki J. S. , Danos S. C. , Remsen C. C.
Published: May 2010

The surface microlayer of two small ponds in Wisconsin were studied from March 1979 through November 1979 using glass plate and screen microlayer sampling devices. The numbers of fungal colony-forming units (CFU) in the surface microlayer were determined and compared with numbers in subsurface waters; diel fluctuations were correlated with nutrients; and experiments were conducted to estimate the contribution of spores to surface microlayer populations. The data obtained indicates that the highest number of fungal CFU were located in the surface microlayers of the ponds studied. The numbers present, as well as their enrichment in the surface microlayer, underwent both seasonal and diel fluctuations. Most of the fungal CFU in the surface microlayer appeared to be spores arriving from both allochthonous and autochthonous sources. Qualitative investigations would be necessary to determine the relative importance of either source to the total numbers of fungi observed.
The growth characteristics of Saccharomycopsis lipolytica: morphology and induction of mycelium formation
Authors: Rodriguez Carmina , Domínguez Angel
Published: May 2010

When Saccharomycopsis lipolytica was grown on minimal medium supplemented with glucose or n-hexadecane, all the cells of the culture remained in the yeast form. In complex medium, a mixed morphology of yeast and mycelial forms appeared. If the cells were grown on minimal medium supplemented with N-acetylglucosamine as the carbon source, a reproducible system for the production of mycelium was obtained. Neither temperature, pH, nor several other carbon sources were able to induce a reproducible yeast–mycelial transition. Mycelium formation is maximal after 12–15 h of incubation (in the presence of N-acetylglucosamine) and decreases with longer incubating times when N-acetylglucosamine is exhausted. During mycelium formation a considerable increase took place in dry weight; the cell numbers, however, remained almost constant between 12–15 h. Electron microscopy shows mycelium with a smooth surface, a great amount of mitochondria and a low degree of branching.
25S ribosomal RNA homologies of basidiomycetous yeasts: taxonomic and phylogenetic implications
Authors: Baharaeen Siavash , Vishniac Helen S.
Published: May 2010

Genera, families, and possibly orders of basidiomycetous yeasts can be defined by 25S rRNA homology and correlated phenotypic characters. The teleomorphic genera Filobasidium, Leucosporidium, and Rhodosporidium have greater than 96 relative binding percent (rb%) intrageneric 25S rRNA homology and significant intergeneric separation from each other and from Filobasidiella. The anamorphic genus Cryptococcus can be defined by morphology (monopolar budding), colony color, and greater than 75 rb% intrageneric homology; Vanrija is heterogeneous. Agaricostilbum (Phragmobasidiomycetes, Auriculariales), Hansenula (Ascomycotera, Endomycota), Tremella (Phragmobasidiomycetes, Tremellales), and Ustilago (Us-tomycota, Ustilaginales) appear equally unrelated to the Cryptococcus, Filobasidiella, and Rhodosporidium spp. used as probes. The Filobasidiaceae and Sporidiaceae, Filobasidiales and Sporidiales, form coherent homology groups which appear to have undergone convergent 25S rRNA evolution, since their relatedness is much greater than that indicated by 5S rRNA homology. Ribosomal RNA homologies do not appear to measure evolutionary distance.
The distribution of large T antigen in simian virus 40 nucleoprotein complexes
Authors: Milthorp Peter , Baumann Ernst , Hand Roger
Published: May 2010

Simian virus 40 large T antigen binds to two types of nucleoprotein complexes from lytically infected cells: those containing replicating virus DNA (100S complexes) and those containing nonreplicating virus DNA (70S complexes). Analysis by agarose gel electrophoresis showed that replicating DNA was found exclusively in 100S complexes, although these complexes also contained large amounts of form I and form II DNA. In contrast, no replicating DNA was found in 70S complexes, and pulse-labeled DNA in these complexes migrated as form I and form II DNA that presumably had recently completed replication. Immunoprecipitation and gel electrophoresis showed that large T antigen was associated with both types of complexes. From 21 to 62% of replicating DNA in 100S complexes was bound to T antigen. Our estimates indicated, however, that more than three-fourths of the DNA molecules in 100S complexes were nonreplicating and unassociated with T antigen. In 70S complexes, 12 to 31% of pulse-labeled DNA was bound to T antigen, but because there were more DNA molecules in the 70S complexes, they contained a greater absolute amount of T antigen.
Metabolism of structurally modified acyclic monoterpenes by Pseudomonas incognita
Authors: Renganathan V. , Madyastha K. Madhava
Published: May 2010

The ability of Pseudomonas incognita to metabolize some structurally modified acyclic monoterpenes was tested. The 6,7 double bond was found essential for these compounds to serve as a substrate for this organism, whereas the same was not true with the 1,2 double bond. Metabolism of dihydrolinalyl acetate by this strain yielded dihydrolinalool, dihydrolinalool-8-carboxylic acid, dihydrolinalyl acetate-8-carboxylic acid, and 4-acetoxy-4-methyl hexanoic acid. A cell-free extract prepared from dihydrolinalyl acetate grown cells transformed dihydrolinalyl acetate into dihydrolinalool and dihydrolinalool-8-carboxylic acid. Based on the identification of various metabolites isolated from the culture medium, and on growth and manometric studies carried out with the isolated metabolites as well as with related synthetic analogs, probable pathways for the biodegradation of dihydrolinalyl acetate are presented.
Acetic, propionic, and oleic acid as the possible factors influencing the predominant residence of some species of Propionibacterium and coagulase-negative Staphylococcus on normal human skin
Authors: Ushijima Tsutomu , Takahashi Megumi , Ozaki Yoshikatsu
Published: May 2010

The minimum inhibitory concentration (MIC) of acetic and propionic acid for resident bacteria on normal human skin, such as Propionibacterium acnes and Staphylococcus epidermidis, was 25 mg/mL or more at any pH tested (pH 5.5–6.8). While the MIC of these acids for most of the transient bacteria was markedly decreased by lowering the pH of the media and at pH 5.5, the mean pH value of the normal human skin, the MIC was 6.25 mg/mL or less. The MIC of oleic acid for some strains of Gram-positive transient bacteria of Streptococcus, Micrococcus, or Bacillus was 100 μg/mL or less at all pH's tested. Staphylococcus aureus was resistant to this acid at pH 6.8, but became as sensitive as Streptococcus when the pH was lowered. The growth of P. acnes, the most predominant resident bacterium, was enhanced markedly and reached a maximum level at 6.25 mg/mL of propionic acid, 12.5 mg/mL of acetic acid, and 50–100 μg/mL of oleic acid. On the basis of these results, we presumed that acetic, propionic, and oleic acids are factors influencing the predominant residence of some species of Propionibacterium and coagulase-negative Staphylococcus on normal human skin.
Intracellular potassium concentration and relative acidity of the ribosomal proteins of methanogenic bacteria
Authors: Jarrell K. F. , Sprott G. D. , Matheson A. T.
Published: May 2010

The intracellular potassium concentration and percentage of acidic ribosomal proteins were determined for nine methanogenic bacteria representing diverse phylogenetic groupings. Representatives of the Methanobacteriaceae family possessed very high internal potassium concentrations: Methanobrevibacter arboriphilus, 1225 mM; Methanobrevibacter smithii, 1065 mM; Methanobacterium thermoautotrophicum, 1103 mM; Methanobacterium bryantii, 861 mM; and Methanobacterium strain G2R, 886 mM. Members of other families tested maintained much lower internal concentrations of potassium. Methanosarcina barkeri (family Methanosarcinaceae) and Methanospirillum hungatei (family Methanomicrobiaceae) maintained approximately 200 mM internal potassium, while Methanococcus voltae (family Methanococcaceae) possessed an intermediate concentration of 725 mM. Those organisms maintaining the highest internal potassium concentrations also had the largest number of acidic ribosomal proteins. There appeared to be a correlation among the phylogenetic placement of the organism (based on 16S rRNA sequence data), its content of intracellular potassium, and the percentage of acidic ribosomal proteins. Those methanogens most closely related to extreme halophiles possessed the highest concentrations of internal potassium and had an increased percentage of acidic ribosomal proteins, both properties of halophilic bacteria.
Flagella-specific bacteriophages of Agrobacterium tumefaciens: demonstration of virulence of nonmotile mutants
Authors: Bradley David E. , Douglas Carl J. , peschon Jacques
Published: May 2010

Bacteriophages GS2 and GS6 for Agrobacterium tumefaciens were shown by electron microscopy to adsorb to flagella. This specificity was confirmed by the finding that phage-resistant mutants were nonmotile. Such mutants retained tumor-inducing virulence and ability to attach to plant cells, indicating that motility was not required for these properties. Both phages had contractile tails and appeared similar in the electron microscope.
Cellulases of an alkalophilic Bacillus strain isolated from soil
Authors: Horikoshi K. , Nakao M. , Kurono Y. , Sashihara N.
Published: May 2010

A cellulolytic alkalophile, Bacillus sp. No. N-4, was isolated from soil and found to be similar to Bacillus pasteurii, except for its ability to grow at high pH. The isolate grew well at a pH ranging from about 8 to 11 and was a good producer of carboxymethyl cellulase (CMCase) activity, which was associated with a multienzyme system. The crude enzyme preparation strongly hydrolyzed carboxymethyl cellulose and had a broad pH activity curve (pH 5–10). Two alkaline CMCases (enzyme E1 and E2) having an optimal pH for enzyme action at pH 10.0 were partially purified. The enzyme E2 was stable up to 80 °C, and E1 up to 60 °C. Both enzymes hydrolyzed cellotetraose and preferentially yielded cellobiose.
Some properties of a highly thermostable α-amylase from a Thermoactinomyces sp.
Authors: Obi S. K. C. , Odibo F. J. C.
Published: May 2010

Thermostable α-amylase from Thermoactinomyces sp. No. 15, isolated from cow dung, was partially purified and characterized. The enzyme was purified (318-fold) by acetone precipitation, ion-exchange chromatography, and gel filtration techniques. The molecular weight was estimated to be 47 800. Optimum enzyme activity was recorded at pH 7 and at 80 °C. The enzyme was stable at pH 5.0–10.0 and retained 74% activity at 100 °C (30 min). Enzyme activation was observed in the presence of Mn2+, Ag+, and Fe2+, but Hg2+ and Zn2+ were inhibitory. Products of hydrolysis of native starches were mainly glucose and maltose.
Morphological stabilization of the glycocalyces of 23 strains of five Bacteroides species using specific antisera
Authors: Lambe Jr. Dwight W. , Mayberry-Carson K. J. , Ferguson Kaethe P. , Costerton J. William
Published: May 2010

Cells of five Bacteroides species were examined following treatment with homologous antisera and staining with ruthenium red. They were enveloped by glycocalyces and these extensive fibrous exopolysaccharide matrices were fully retained as an integral "capsule" by some cells, while other cells showed "capsule" as well as detached glycocalyx components forming an intercellular "slime." These extensive glycocalyces collapsed during dehydration for electron microscopy and formed electron-dense accretions on cell surfaces and electron-dense reticula in intercellular spaces when the cells were treated with heterologous antiserum or when antibody stabilization was omitted. The glycocalyces of all strains, both stabilized and unstabilized, were observed outside the outer membranes of cell walls that showed the "classic" gram-negative structural organization. Appropriate modifications of the indirect fluorescent antibody test demonstrated an integral "capsule" on all strains examined; detached glycocalyx and varying amounts of slime were demonstrated after stabilization with homologous, but not heterologous, antiserum.
A growth initiation factor involved in magnesium utilization by certain soil bacteria
Authors: Casida Jr. L. E.
Published: May 2010

Actinomyces humiferus was shown to require relatively high levels of magnesium for growth initiation. This growth initiation response to magnesium was graded. Live, but not heat-killed, cultures of Azotobacter vinelandii cells could replace at least a part of the magnesium requirement when Act. humiferus and Azo. vinelandii were grown together as a dual culture. However, it was necessary that the conditions for the dual culture be such that the Azo. vinelandii cells underwent some lysis. In fact, the initial rate of lysis of the Azo. vinelandii cells was increased in the presence of Act. humiferus, presumably because Act. humiferus was able to remove magnesium from the medium so it was not available to Azo. vinelandii. The magnesium requirement of Act. humiferus for growth initiation could also be replaced by a heat-labile factor found in culture filtrates of Act. humiferus and Azo. vinelandii grown as monocultures and dual cultures. This factor, however, was also present in culture filtrates of Arthrobacter globiformis, Nocardia salmonicolor, and Micrococcus luteus. It was not present in culture filtrates of Escherichia coli, Agromyces ramosus, or Ensifer adhaerens. From these results it appears that several, but not all, bacteria produce a heat-labile factor that is involved in marshalling magnesium for use in growth initiation.
P1 bacteriophage and tellurite sensitivity in Klebsiella pneumoniae and Escherichia coli
Authors: Tomás Juan , Regué Miguel , Parés Ramón , Jofre Juan , Kay William W.
Published: May 2010

Klebsiella pneumoniae and Escherichia coli respond inversely toward P1 bacteriophage or [Formula: see text]. Klebsiella pneumoniae is resistant to both antagonists and E. coli is sensitive. However, P1 cmts lysogens (P1 cmts resistant) of K. pneumoniae became sensitive to tellurite and when cured from P1 cmts regained resistance. Escherichia coli spontaneous mutants selected for resistance to either P1 or [Formula: see text] were collaterally resistant to the other. As well, [Formula: see text] enhanced the adsorption of P1 vir to both E. coli and K. pneumoniae. Several outer membrane proteins were enhanced in the K. pneumoniae lysogens and were reduced in E. coli lysogens; one of which was the same molecular weight (77 000) in both bacteria. When partially purified it enhanced the plaque efficiency of P1 vir. Lipopolysaccharide (LPS) from E. coli C600 inactivated P1 vir, but neither the P1 lysogens nor LPS derived from the lysogens inactivated P1 vir. Escherichia coli P1 lysogens produced only heptose-deficient LPS. It is suggested that both LPS and outer membrane protein(s) comprise the P1 receptor. [Formula: see text] may interact with one or both components.
The growth of Paracoccus halodenitrificans in a defined medium
Authors: Hochstein Lawrence I. , Tomlinson Geraldine A.
Published: May 2010

A synthetic medium, consisting of inorganic salts and any of a number of carbon sources, supported the aerobic growth of Paracoccus halodenitrificans when supplemented with thiamine. The same medium plus an appropriate nitrogenous oxide supported anaerobic growth when additionally supplemented with methionine. The observation that vitamin B12 or betaine replaced methionine suggested that P. halodenitrificans had a defect in the cobalamin-dependent pathway for methionine biosynthesis, as well as the inability to synthesize betaine when growing anaerobically.
Sulfur isotope fractionation during reduction by different clostridial species
Authors: Laishley E. J. , Tyler M. G. , Krouse H. R.
Published: May 2010

Sulfur isotope composition patterns for sulfide evolved from cultures supplemented with 1 mM Na2SO3, suggest that an inducible dissimilatory type [Formula: see text] reduction pathway, as previously found in C. pasteurianum, probably exists in many clostridial species. Data are presented for five additional species which include pathogens and nonpathogens.
The derivation and use of mice which do not harbour lactobacilli in the gastrointestinal tract
Authors: Tannock G. W. , Archibald R. D.
Published: May 2010

Penicillin treatment used in conjunction with germfree technology has allowed the derivation of a colony of BALB/c mice which do not harbour lactobacilli in the gastrointestinal tract. The animals continue to harbour Gram-negative anaerobes and coliforms, but not enterococci or filamentous segmented ileal microbes. Isolates of lactobacilli from rodents were able to colonize the gastrointestinal tract of the mice; an isolate from a fowl could not establish in these animals.
Polyacrylamide gel electrophoresis of Bacteroides succinogenes
Authors: Begbie R. , Stewart C. S.
Published: May 2010

Polyacrylamide gel electrophoresis (PAGE) of sodium dodecyl sulphate (SDS) extracts of bacterial cells was used to assess the similarity of polypeptide patterns in 15 isolates of the rumen cellulolytic bacterium Bacteroides succinogenes. Analysis of densitometer traces of the polypeptide band patterns suggested that the majority of the isolates tested were closely related to the type strain S85. Representatives of other species of Gram-negative rumen bacteria had distinct SDS–PAGE patterns, and it is concluded that SDS–PAGE is a useful aid to the identification of B. succinogenes.