bluuebunny/crossref_metadata_2025 huggingface dataset:
Temperature-dependent pattern of heat shock protein synthesis in psychrophilic and psychrotrophic microorganisms
Authors: McCallum Kirk L. , Heikkila John J. , Inniss William E.
Published: May 2010

The patterns of proteins synthesized by the arctic psychrophilic bacterium Res-10 and the psychrotroph Bacillus psychrophilus during various heat shocks up to 32 °C were examined. Both microorganisms were found to display temperature-dependent patterns of heat shock protein synthesis. Elevation of the incubation temperature of the arctic psychrophile from 0 to 15, 20, 25, or 32 °C induced the synthesis of at least 19 heat shock proteins. Imposing similar heat shock upon cells of the psychrotroph resulted in the induction of at least 25 heat shock proteins. Examination of the effect of the transcriptional inhibitor rifampicin on the synthesis of heat shock proteins revealed that the primary control of heat shock protein synthesis lies at the transcriptional level in both microorganisms.
Inhibition of L-lysine uptake by α-methyl lysine in Escherichia coli and Bacillus sphaericus
Authors: Regenstreif Carrie A. , Kelland Janice G. , Pansare Sunil V. , Vederas John C. , Pickard Michael A.
Published: May 2010

α-Methyl lysine was investigated as a potential inhibitor of lysine transport in Escherichia coli and Bacillus sphaericus. At equimolar concentrations, no inhibition was observed in either organism, but at 10 × and 100 × the lysine concentration, α-methyl lysine caused a 20–50% reduction in the initial rate of lysine uptake in both bacteria. A similar inhibitory effect was observed with ε-N-methyl lysine on lysine uptake in B. sphaericus, but not in E. coli. α-Methyl lysine had a reduced effect on ornithine uptake and no effect on arginine transport in either bacterium.
Degradation of orcinol by Aspergillus niger
Authors: Sahasrabudhe S. R. , Lala D. , Modi V. V.
Published: May 2010

Aspergillus niger could utilize orcinol (5-methyl-resorcinol or 3,5-dihydroxytoluene) as the sole source of carbon and energy. In the first step of catabolism A. niger hydroxylates orcinol to form 2,3,5-trihydroxytoluene. Its oxidized form, 2-hydroxy-6-methyl-1,4-benzoquinone, was also formed in the culture medium during growth of this organism. Orcinol-grown cells showed a net increase in the intracellular acetate pool, compared with glucose-grown cells. Cell-free extracts of orcinol-grown cells showed higher activity of orcinol hydroxylase, catechol 1,2-oxygenase, and isocitrate lyase than that of glucose-grown cells. Both orcinol-grown and resorcinol-grown cells exhibit similar respiratory activity on all the substrates checked.
Influence of environmental factors on the growth and survival of Phytophthora clandestina
Authors: Wong D. H. , Sivasithamparam K. , Barbetti M. J.
Published: May 2010

The effects of temperature, pH, and osmotic water potential on the growth on lima bean agar and survival in soil of Phytophthora clandestina were investigated. On agar it grew over a wide pH range of 4–9 and growth increased as the pH of the initial medium rose from 4 to 6 at temperatures of 15, 20, and 25 °C. Growth was reduced by 58, 56, and 65% under acidic (pH 4) or by 54, 63, and 32% under alkaline (pH 9) conditions when compared with growth at pH 6 at 15, 20, and 25 °C, respectively. At 10, 15, 20, and 25 °C growth was reduced with increasing water stress. Generally growth increased with progressively increasing incubation temperatures up to 20 °C. Osmotic water potential of less than −12bars (1 bar = 100 kPa) prevented mycelial growth of P. clandestina. Maximum growth occurred on lima bean agar (0 bar) without KCl amendment at all temperatures. Survival of the pathogen within pasteurized soil was increased under cooler conditions (5–10 °C) at all water potentials tested (−0.01, −0.026, and −0.063 bars). At higher temperatures (15–32 °C) P. clandestina survived better under wetter soil conditions.
Detection of fungal fimbriae by protein A – gold immunocytochemical labelling in host plants infected with Ustilago heufleri or Peronospora hyoscyami f.sp. tabacina
Authors: Day A. W. , Gardiner R. B. , Smith R. , Svircev A. M. , McKeen W. E.
Published: May 2010

Sections of leaves of Nicotiana tabacum L. infected with Peronospora hyoscyami De Bary f.sp. tabacina (Adam) Skalicky and of Erythronium americanum Ker. infected with Ustilago heufleri Fuckel were treated with an antiserum directed against the fimbriae of U. violacea Fuckel and other fungi. The sections were then treated with protein A – gold complexes to detect the presence and location of fimbrial antigens following transmission or scanning electron microscopy. Control preparations involved sections of uninfected leaves, as well as a range of serological control treatments. The infected leaf sections were heavily labelled with gold particles indicating the presence of fimbrial antigens, whereas the control preparations showed only a low background level of labelling. Gold particles were detected on the sections of hyphae, on haustoria, and on the nearby plant cells. The intensity of labelling was much higher for P. hyoscyami f. sp. tabacina than for U. heufleri and was particularly high in the walls of the former species. Relatively high levels of labelling occurred over the cells of infected hosts, but little or none occurred over the cells of uninfected host tissues, or of the infected host tissues treated with a range of serological controls. This high level of labelling was not associated with specific host structures in P. hyoscyami, but was frequently associated with the chloroplasts in U. heufleri. The antigens detected inside the host plant cells appear to indicate that fungal fimbrial protein, either as polymerized fibrils or as isolated subunits, can penetrate the host plasma membrane and therefore enter the host cytoplasm. An alternative possibility is that these antigens derive from host produced proteins synthesized as a result of infection. These results suggest the possibility that fungal fimbriae may play an important role in the molecular interaction between pathogen and host.
NADP+ production using thermostable NAD+ kinase of Corynebacterium flaccumfaciens AHU-1622
Authors: Matsushita Hideyuki , Yokoyama Sadaji , Obayashi Akira
Published: May 2010

A sonicate of Corynebacterium flaccumfaciens AHU-1622 had the highest NAD+ kinase activity (1.22 mU/mL culture broth) of the strains of bacteria we investigated. This enzyme was thermostable, with activity maintained at 50 °C for 1 h. This treatment inactivated phosphatase activity. Resting cells of the bacterium also had NAD+ kinase activity when treated at 60 °C for 30 min with 0.2% Triton X-100. NADP+ production was achieved using 8 μmol NAD+, 8 μmol ATP, 16 μmol MgCl2, 1.6 μmol NaN3, and 12 mU NAD+ kinase (0.1 g of permeabilized wet cells) in 2 mL of 0.1 M phosphate buffer, pH 7.5. The conversion ratio of NADP+ from NAD+ was 75% after 10 h of incubation at 50 °C, and the amount of accumulated NADP+ was 3 μmol/mL of reaction mixture. The NAD+ kinase activity of the permeabilized cells was stable and did not decrease after repeated use.
Evaluation of radioimmunoassay performance for staphylococcal enterotoxin in foods: application of external quality assessment survey
Authors: Dickie N. , Rayman K. , Akhtar M. , Foster R. , Gardiner M.-A. , Jarvis G.
Published: May 2010

An external quality assessment survey for staphylococcal enterotoxin A, B, and C2 determinations was performed in the collaborative study. Three analysts in two laboratories took part. Three types of food, cheese, salami, and pasta, were artificially contaminated with either one toxin only or all three toxins. A total of 378 analyses were performed. The group mean of the analytical values corresponded fairly well to the given enterotoxin concentrations. However, a considerable interlaboratory imprecision was found despite analyses being performed with the same reagents and methodology.
R-plasmid transfer in soil and water
Authors: Trevors J. T. , Oddie K. M.
Published: May 2010

R-plasmid transfer in Escherichia coli was investigated in nutrient broth, sterile soil, and sterile stream water. Plasmid transfer occurred in broth cultures at 30 and 22 °C, but not at 15 °C. R-plasmid transfer was not observed at 30, 22, and 15 °C in nonamended sterile soil and stream water. The addition of nutrients to sterile stream water and soil allowed plasmid transfer to occur at temperatures ranging from 15 to 30 °C. R-plasmid transfer was also observed in soil adjusted from 20 to 100% of its water-holding capacity.
Redundant spore coat structures in an entomopathogenic Bacillus
Authors: Brooks Carolyn B. , Green B. M.
Published: May 2010

An ultrastructural study of an insecticidal bacillus isolated from the silver-spotted skipper (Epargyreus clarus) revealed unusual spore coat redundancy. Spores developed simultaneously with appendages which were always attached to the spore coat and remained attached even after the mother cell had lysed. The appendages were multilobular or attached plates and were encased by lamellar coverings and a fibrous outer coat which were similar to those surrounding the attached spore.
Comparative analyses of the sheath structures of Methanothrix concilii GP6 and Methanospirillum hungatei strains GP1 and JF1
Authors: Patel Girishchandra B. , Sprott G. Dennis , Humphrey Richard W. , Beveridge Terry J.
Published: May 2010

The proteinaceous sheath of the aceticlastic methanogen Methanothrix concilii strain GP6 was isolated by exposure of the cells to 5 N NaOH at room temperature, followed by incubation with 1% (w/v) sodium dodecyl sulphate (100 °C, 10 min). The sheaths of Methanospirillum hungatei strains JF1 and GP1 could be isolated by milder alkali treatment (0.1 N NaOH at room temperature) and subsequent sodium dodecyl sulphate treatment (90 °C, 15 min). The isolated sheaths from each bacterium resembled hollow tubes which were composed of hoops piled on top of one another; all sheaths were several micrometers long but those of both Msp. hungatei strains were 0.5 μm wide and those of Mtx. concilii were 0.8μm wide. All three types of sheath possessed an identical subunit arrangement with p2 symmetry (a = 5.6, b = 2.8, and γ = 86°) which was confirmed by electron diffraction. On isolation, the Msp. hungatei sheaths contained complex, multilayered "cell spacer" plugs which possessed hexagonal symmetry, whereas those of Mtx. concilii were not as complex and their subunit arrangements resembled concentric rings. The plugs of Msp. hungatei could be removed by the mild alkali used in sheath isolation, but alkali did not affect the Mtx. concilii plugs. Whereas the GP1 sheath could be extensively disintegrated by a combination of sodium dodecyl sulphate and mercaptoethanol (90 °C, pH 9.0), the sheaths of strain JF1 and Mtx. concilii were unaffected. Treatment with 0.1 N NaOH at 80 °C resulted in complete disintegration of the sheaths isolated from the two Msp. hungatei strains, whereas the Mtx. concilii sheaths were resistant. Amino acid analysis of hydrolyzed sheaths indicated that unlike Mtx. concilii, those of the Msp. hungatei strains had higher proportions (on a mol% basis) of alanine and aspartate but considerably lower proportions of glutamate, histidine, and arginine. The predominant sugar was mannose, arabinose and glucose for the sheaths of Mtx. concilii, Msp. hungatei strains JF1 and GP1, respectively. All sheath preparations contained metals, notably zinc in the case of Mtx. concilii, and calcium in the Msp. hungatei strains. We conclude that although the subunit arrangements of the three sheath types are similar, there are marked differences in their chemical compositions. In addition, the subunit arrangements of the spacer plugs differ from those of the respective sheaths, and the plugs of Mtx. concilii are physically different from those of Msp. hungatei.
Survival of indigenous enteric viruses during storage of waste water sludge samples
Authors: Hurst Christon J. , Goyke Tamara
Published: May 2010

The stability of indigenous enteric viruses in samples of settled primary and mixed-liquor activated sludges was studied at 2, 23, and −70 °C. Changes of virus titer which occurred in these samples were followed during an 84-day observation period, with rates of change then calculated by least-squares regression. Virus survival was found to be statistically dependent (p ≤ 0.05) upon storage temperature but not sludge solids content. Based upon the observed rates of inactivation, the average times which would be required for a 90% decrease in virus titer are 26 days at 23 °C, 180 days at 2 °C, and 163 days at −70 °C. As a group, the rates of virus inactivation observed at 2 °C were statistically different (p ≤ 0.05) from those observed at 23 °C, but not different from those observed at −70 °C. The three study temperatures were selected to approximate holding of samples in an air-conditioned room, on wet ice (H2O), and on dry ice (CO2).
Traitement aérobie du lisier de porc: aspects microbiens
Authors: Doyle Y. , Guay R. , Noüe J. de la , Asselin J.
Published: May 2010

Not available
Effect of radiation dose on the recovery of aerobic and anaerobic bacteria from mice
Authors: Brook Itzhak , Walker Richard I. , MacVittie Thomas J.
Published: May 2010

The presence of aerobic and anaerobic bacteria in the blood, spleen, and liver was investigated in mice that were exposed to 7, 8, 9, or 10 Gy 60Co radiation. Microorganisms were detected more often in animals exposed to higher doses of radiation. The number of mice that were culture positive and the number of isolates in one site increased with increasing dose. Bacteria were recovered in mice killed at various times after radiation, in 3 of 100 mice exposed to 7 Gy, in 13 of 100 irradiated with 8 Gy, in 23 of 90 exposed to 9 Gy, and in 34 of 87 irradiated with 10 Gy. The predominant organisms recovered were Escherichia coli, anaerobic Gram-positive cocci, Proteus mirabilis, Staphylococcus aureus, and Bacteroides spp. Escherichia coli and anaerobes were more often isolated in animals exposed to 10 Gy, while S. aureus was more often recovered in those irradiated with 9 Gy. These data demonstrate a relationship between the dose of radiation and the rate of infection due to enteric aerobic and anaerobic bacteria.
Characterization and partial purification of a broad spectrum antibiotic AS-48 produced by Streptococcus faecalis
Authors: Gálvez A. , Maqueda M. , Valdivia E. , Quesada A. , Montoya E.
Published: May 2010

Streptococcus faecalis S-48 produces a broad spectrum antibiotic, active against Gram-positive and Gram-negative bacteria. This substance is produced in solid and liquid media and also in a defined basal medium. It is sensitive to protease, pronase, or trypsin, heating at 70 °C, and alkaline pH, but resistant to treatment with lipase, lysozyme, alkaline phosphatase, DNAase, RNAase, acidic or neutral pHs, and also lower temperatures (60 °C). Several organic solvents cause precipitation, but not inactivation. This antibiotic has been partially purified by gel filtration and further ion-exchange chromatography. Its molecular weight has been estimated close to 2000. The biological activity of this antagonistic substance against the selected indicator strains, Streptococcus faecalis S-47 and Escherichia coli U-9, is bactericidal. The characterization of this substance, initially classified as a bacteriocin, indicates that it is an antibiotic of peptidic nature. The significance of antibiotic occurrence in group D of the genus Streptococcus is also discussed.
Cell division and filament splitting in Methanothrix concilii
Authors: Beveridge Terry J. , Harris Bob J. , Patel Girishchandra B. , Sprott G. Dennis
Published: May 2010

Cells of Methanothrix concilii do not possess rigid, shape-forming cell walls; they obtain their cellular form from the portions of the sheath and spacer plugs which enclose them. Electron microscopy has shown that cell division proceeds by the ingrowth of spacer plugs, like the closing of a camera iris, from select regions of the sheath; this process forces the cells to split in two. Therefore, each spacer plug which traverses the filament of cells is a completed division annulus. Spacer plugs are two-layered structures; one layer is an assembly of fine concentric rings and is the first to be laid down during the division ingrowth. The second layer consists of larger, raised, concentric ribbons which progressively follow the advance of the first layer during division. Although cells within the filament are typically 2.5 μm long, new daughter cells are ca. 1.0 μm and can grow to ca. 4.0 μm before division begins. Frequently, a developing spacer plug partitions a cell so that one daughter is a small, nonreplicating unit of protoplasm sandwiched between two completed plugs; eventually, this protoplasmic unit dies leaving a void in the chain of cells. The filament is susceptible to breakage at this juncture. In this instance, each of the two "void" plugs becomes a new terminal plug for the new ends of the split filament. This type of replication requires both cell division and filament splitting, and the series of structural events which are involved present a new form of prokaryotic division.
Characterization of the stability functions and inverted repeat structure X3 of the IncFI plasmid ColV2-K94
Authors: Weber Peter C. , Palchaudhuri Sunil
Published: May 2010

A region of the IncFI plasmid ColV2-K94 which showed homology to the sop partitioning genes of F was cloned and characterized in an attempt to study the stability functions of this element. The sop region contained the incD incompatibility determinant common to many IncFI plasmids, but could not confer on ColV2-K94 miniplasmids the same stable inheritance found in the intact ColV2-K94; thus, other functions appear to be required for efficient plasmid maintenance. Adjacent to the area of sop homology was the X3 region, which was found to contain three inverted IS1-like sequences. The X3 region of ColV2-K94 was similar in organization to the aerobactin iron uptake region of ColV3-K30, but ColV2-K94 lacked the ability to synthesize either the aerobactin siderophore or its outer membrane receptor.
Glutathione overproduction by selenite-resistant Escherichia coli
Authors: Schmidt Michael G. , Konetzka Walter A.
Published: May 2010

Use of resistance to sodium selenite is an effective method for the selection of gluthathione overproduction in Escherichia coli.
Oxygen recognition in aerotactic behaviour of Azospirillum brasilense Cd
Authors: Reiner Orly , Okon Yaacov
Published: May 2010

Oxygen recognition in aerotactic behaviour of Azospirillum brasilense was studied. Spectral studies of membrane preparations of A. brasilense Cd revealed three terminal oxidases: cytochromes aa3, o, and d. The possible involvement of each of these cytochromes in oxygen reception was evaluated. Since neither reducing the level of cytochrome aa3 in the bacteria nor inhibition of cytochrome aa3 by low concentrations of cyanide affected aerotaxis, it was concluded that cytochrome aa3 is not the oxygen receptor. Cytochromes o and d are inhibited by high concentrations of cyanide which also inhibit aerotaxis. Of these two, cytochrome o seems more likely to be the oxygen receptor, since antimycin A, which inhibits the reduction of this cytochrome (but not that of cytochrome d), completely inhibited aerotaxis. By using tethered cells, it was demonstrated that A. brasilense is microaerophilic, as it is attracted to oxygen concentrations lower than those present in the air (20%).
Dynamics of RP4 plasmid transfer between Xanthomonas campestris pv. corylina and Erwinia herbicola in hazelnut tissues, in planta
Authors: Manceau Charles , Gardan Louis , Devaux Martine
Published: May 2010

We have shown that the transfer of plasmid RP4 took place between two strains of Xanthomonas campestris pv. corylina and from Xanthomonas campestris pv. corylina to Erwinia herbicola and vice versa when the strains were inoculated in hazelnut tissues in an experimental orchard. Transfer occurred throughout all seasons and was independent of the physiological conditions of the host tissues. The main factor governing transfer in planta appeared to be the frequency of contacts among donors and recipients. The frequency of transfer was correlated with the level of bacterial populations. RP4 was stable in the inoculated strains of Xanthomonas campestris pv. corylina as well as in Erwinia herbicola in hazelnut tissue. RP4 was detected in two isolates of resident epiphytic microflora, Pseudomonas fluorescens and Erwinia herbicola.
An estimate of the extent of deamination of L-serine in auxotrophs of Escherichia coli K-12
Authors: Ramotar D. , Newman E. B.
Published: May 2010

We have shown that serine–glycine auxotrophs of Escherichia coli K-12 use exogenous L-serine inefficiently as a source of biosynthetic intermediates. Much of the L-serine supplied in the medium is not used to satisfy the auxotrophic requirement, owing to its diversion by L-serine deaminase, presumably to pyruvate. This is the first proof that the activity known as L-serine deaminase actually deaminates L-serine in vivo.
Effects of an altered developmental pattern on amino acid uptake for a protoplast isolate of the fungus Entomophaga aulicae under mass-fermentation conditions
Authors: Nolan Richard A.
Published: May 2010

The effects of an altered developmental pattern on amino acid uptake for a protoplast isolate of the fungus Entomophaga aulicae were studied under mass-fermentation conditions. Isolate 655A had previously developed through the hyphal body stage, but subsequently lost this ability (then designated I655B) and then developed only as far as the germination of the late fusion sphere stage. This alteration in developmental pattern was accompanied by a shift in the overall amino acid uptake pattern. For comparative purposes, another isolate (I521) which developed only as far as the germination of the late fusion sphere stage was included. The general amino acid uptake patterns fell into three categories and emphasize the similarity of I521 and I655B: (i) earlier and more complete final utilization by isolates 521 and 655B for glutamine, leucine, aspartic acid, threonine, and methionine, (ii) earlier utilization by isolate 655A with more complete final utilization by isolates 521 and 655B for asparagine and proline, and (iii) earlier utilization by isolates 521 and 655A with more complete final utilization by isolates 521 and 655B for serine and tyrosine. The first detectable utilization of serine coincided with late fusion sphere germination for isolates 521 and 655B. During the rapid increase in hyphal body levels for I655A, all added amino acids (except proline, asparagine, and serine which were first utilized earlier) were utilized for the first time. Except for the timing of the initial day of detectable utilization, the pattern of glucose utilization was similar for all three isolates.
Production of induced laccase by the fungus Rhizoctonia praticola
Authors: Shuttleworth Kay L. , Postie Lori , Bollag Jean-Marc
Published: May 2010

The ability of the fungus Rhizoctonia praticola to produce an induced extracellular laccase was examined. Potential inducers, including substituted phenols, anilines, and benzoic acids, were added at a concentration of 1 mM to the growth media of fungal cultures. Of the 11 compounds tested, 5 were found to have an inductive effect. The most effective inducer, p-anisidine (p-methoxyaniline), stimulated laccase production by a factor of 30. Other parameters which influenced the production of laccase were temperature, condition of the mycelia at the time of the induction, and the concentration of the inducer. A comparison of the p-anisidine induced laccase with the constitutive laccase showed noticeable similarities in Km, pH optimum, and mobility in gel electrophoresis, suggesting that the two enzymes may be similar.
Molecular weight determination and partial characterization of Klebsiella pneumoniae hemolysins
Authors: Barberis Lucila Isabel , Eraso Alberto Jorge , Pàjaro Maria Cristina , Albesa Inès
Published: May 2010

Two thiol-activated Klebsiella pneumoniae hemolysins were purified from growth media by means of salt precipitation, gel filtration, ion-exchange chromatography, and polyacrylamide gel electrophoresis. The hemolysins peaks coincided with the protein and glycoprotein peaks as determined by chromatography and electrophoresis, The molecular weights, estimated by gel filtration, were 8400 and 19 000; by sodium dodecyl sulphate–polyacrylamide gel electrophoresis, the values were calculated as 15 500 and 27 000. The electrophoretic bands were best detected by the periodic acid–Schiff method. Reduction of the disulfide linkages did not cause the originally larger molecule to break into 8400 and 19 000 hemolysins. However, trypsin treatment cleaved the 19 000 hemolysin into an active moiety, with an electrophoretic migration similar to the 8400 hemolysin. A naturally occurring proteolytic activity was investigated using pepstatin and antipain. When the trypsin inhibitor was added to the system, the hemolytic activity was detected only in the 19 000 hemolysin and the smaller hemolysin was absent.
Prevention of Clostridium difficile induced mortality in gnotobiotic mice by Saccharomyces boulardii
Authors: Corthier G. , Dubos F. , Ducluzeau R.
Published: May 2010

Oral preventive treatment of gnotobiotic mice by Saccharomyces boulardii significantly decreased mortality following Clostridium difficile infection. A single S. boulardii ingestion protected 16% of mice, whereas 56% were protected when S. boulardii was given continuously in the drinking water. No direct antagonistic effect of the yeast on C. difficile numbers was detected, whereas a modulation of fecal cytotoxin production was demonstrated.
Regulation of phosphoenolpyruvate carboxykinase and pyruvate kinase in Saccharomyces cerevisiae grown in the presence of glycolytic and gluconeogenic carbon sources and the role of mitochondrial function on gluconeogenesis
Authors: Wilson Albert J. , Bhattacharjee J. K.
Published: May 2010

Phosphoenolpyruvate carboxykinase (PEPCKase) and pyruvate kinase (PKase) were measured in Saccharomyces cerevisiae grown in the presence of glycolytic and gluconeogenic carbon sources. The PEPCKase activity was highest in ethanol-grown cells. However, high PEPCKase activity was also observed in cells grown in 1% glucose, especially as compared with the activity of sucrose-, maltose-, or galactose-grown cells. Activity was first detected after 12 h when glucose was exhausted from the growth medium. The PKase activity was very high in glucose-grown cells; considerable activity was also present in ethanol- and pyruvate-grown cells. The absolute requirement of respiration for gluconeogenesis was demonstrated by the absence or significantly low levels of PEPCKase and fructose-1,6-bisphosphatase activities observed in respiratory deficient mutants, as well as in wild-type S. cerevisiae cells grown in the presence of glucose and antimycin A or chloramphenicol. Obligate glycolytic and gluconeogenic enzymes were present sumultaneously only in stationary phase cells, but not in exponential phase cells; hence futile cycling could not occur in log phase cells regardless of the presence of carbon source in the growth medium.
A screening method for cytochrome P-450 organic peroxidase activity and application to hydrocarbon-degrading bacterial populations
Authors: Wyndham R. C.
Published: May 2010

A method to detect the expression of hemoproteins with organic hydroperoxide reducing activity was developed to screen bacterial populations isolated from heavy oils and oil sands. The method is based on the activity of cytochrome P-450 as catalyst in the reduction of cumene hydroperoxide by artificial electron donors. There was no cross-reactivity with true peroxidases involved in the reduction of hydrogen peroxide. Cross-reactivity with catalase could be eliminated with appropriate inhibitors but did not normally interfere with the detection method. A preliminary screen resulted in the isolation of Acinetobacter calcoaceticus and a range of Gram-positive bacteria with organic peroxidase activity. Carbon monoxide difference spectra of cell-free extracts of the isolates revealed the presence of a hydrocarbon-inducible cytochrome P-450 in Acinetobacter calcoaceticus and in coryneform and actinomycete bacteria. A CO-binding cytochrome of unknown type with a Soret absorption maximum at 424 nm and cumene hydroperoxidase activity was also detected in some strains.
Analysis of microcalorimetric curves for bacterial identification
Authors: López D. , Viñas M. , Lorén J. G. , Bermúdez J.
Published: May 2010

A numeric method is suggested for the treatment of microcalorimetric curves of bacterial growth to provide a new tool for their automatic identification. In this method the microcalorimetric curves are searched against certain reference profiles (stored in a library) by means of a cross-correlation analysis and a parametric comparison. The matching between the new curve and each reference profile is evaluated by means of a specific identification coefficient which provides an objective criterion for the identification of each species. The reliability of the method is discussed.
Interbacterial adhesion between Pseudomonas aeruginosa and indigenous oral bacteria isolated from patients with cystic fibrosis
Authors: Komiyama K. , Habbick B. F. , Gibbons R. J.
Published: May 2010

Interbacterial adhesion between strains of Pseudomonas aeruginosa and strains of indigenous oral bacteria, both of which were isolated from the oral cavity of cystic fibrosis patients, was investigated by the phenomenon of the coaggregation reaction. A total of 22 strains of P. aeruginosa were isolated from the oral cavitiy of 17 patients and examined for their abilities to coaggregate with 5 strains each of Streptococcus sanguis, Streptococcus mitis, Actinomyces viscosus, and Actinomyces naeslundii. Coaggregation reactions were common between these oral bacteria and both the mucoid and nonmucoid variants of P. aeruginosa. All strains of P. aeruginosa were also able to agglutinate neuraminidase-treated or untreated human erythrocytes of blood types A, B, and O. Positive coaggregation reactions were further characterized by determining the effects of several sugars, and of heat and protease treatments of the bacteria. None of the coaggregation reactions were inhibited by 0.05 M lactose, galactose, glucose, fucose, or mannose. All coaggregation reactions were dependent upon heat- and protease-sensitive components of the Pseudomonas. Thus, the interbacterial adhesions between P. aeruginosa and the oral bacteria studied appears to involve adhesins on the Pseudomonas cell, which bind to complementary receptors, on the cell surfaces of oral bacteria. The apparent prevalence and diversity of interbacterial adhesions between P. aeruginosa strains originating from the oral cavity of cystic fibrosis patients and strains of the indigenous oral bacteria suggest that some of these reactions may affect the extent to which P. aeruginosa colonizes in the oral cavity of cystic fibrosis patients, and thereby, influence susceptibility of the host to infection.
A study of factors affecting the sensitivity of the passive haemagglutination method for serotyping Campylobacter jejuni and Campylobacter coli and recommendations for a more rapid procedure
Authors: Fricker C. R. , Alemohammad M. M. , Park R. W. A.
Published: May 2010

Factors affecting the sensitivity of the passive haemagglutination method for serotyping campylobacters have been studied. The concentration of red blood cells during the haemagglutination stage of the procedure markedly affected the titer obtained. An increase in concentration of red blood cells resulted in a lower titer, with titers being inversely proportional to red blood cell concentration. No differences in titer were observed when erythrocytes were sensitized at a range of pH values between pH 5.0 and pH 8.0. The time required for antigen extraction and for red blood cell sensitization was shown to be 15 min each, thus resulting in a reduction in the time required for serotyping. Furthermore, use of avian erythrocytes enabled the haemagglutination reactions to be read after incubation for only 1 h. Combining these procedures with a rapid slide haemagglutination test enables a single worker to serotype over 100 C. jejuni and C. coli isolates within 1 working day.
Les systèmes membranaires de Scopulariopsis brevicaulis. I. Isolement et caractérisation
Authors: Fonvieille Jean-Louis , Touze-Soulet Jane-Marie , Dargent Robert
Published: May 2010

Membranes isolated (except mitochondrial membranes) from mycelium of Scopulariopsis brevicaulis were separated by continuous density gradient centrifugation using Percoll at a concentration of 10%. This method was compared with discontinuous sucrose density gradient centrifugation. Isolated membrane systems were characterized by enzymatic markers (NADPH and NADH cytochrome c reductases, ATPase, AMPase, IDPase) and by cytochemical reactions using electron microscopy (Thiéry test, phosphotungstic acid – chromic acid). The best separation of membranes was obtained with continuous density gradient centrifugation using 10% Percoll.
Les systèmes membranaires de Scopulariopsis brevicaulis. II. Étude comparée de leur composition lipidique
Authors: Fonvieille Jean-Louis , Touze-Soulet Jane-Marie , Montant Charles
Published: May 2010

Biochemical studies of Scopulariopsis brevicaulis membranes (except mitochondrial membranes), in particular their lipid composition, were undertaken using plasma membranes and fractions containing smooth endoplasmic reticulum and Golgi apparatus membranes. The results obtained by two separation techniques, a continuous Percoll gradient and a discontinuous sucrose gradient centrifugation, were similar. Depending on the isolation method used, the plasma membrane contained 30 or 33% protein and 23 or 30% lipid of which 16.5 or 18% was phospholipid. The sterol/phospholipid ratio was 1.98 or 2.28. The endoplasmic reticulum + Golgi fraction contained 21 or 26.7% protein and 43 or 50% lipid of which 7 or 10% was phospholipid. The sterol/phospholipid ratio was 0.85 or 0.81.
Enzyme-linked immunosorbent assay on nitrocellulose membranes (dot–ELISA) in the serodiagnosis of plant pathogenic bacteria
Authors: Lazarovits G. , Zutra D. , Bar-Joseph M.
Published: May 2010

The usefulness of enzyme-linked immunosorbent assay on nitrocellulose membranes (dot–ELISA) for diagnosis and identification of plant pathogenic bacteria was tested. Five pathovars of Xanthomonas campestris and two antisera, one produced against pv. vesicatoria and the other against pv. translucens, were used in a model system. A 10-min incubation of the bacterial cells, dot blotted on membranes, in diluted sera, followed by either alkaline phosphatase conjugated protein A or goat antirabbit globulin, resulted in a specific reaction between the homologous serum and bacteria. Populations of 1000–2000 cfu per spot (ca. 0.3 cm2) could be detected with these reagents. The streptavidin–biotinylated peroxidase complex produced a definitive reaction with as few as 800 cfu, but cross-reactions became evident at the higher cell concentrations among all five pathovars in tests with both antisera. Cell-free extracts, obtained by centrifugation of boiled bacteria, reacted similarly to live cells. Unrelated bacteria did not react with either antiserum. Extracts of lesions from tomato and pepper leaves infected with X. campestris pv. vesicatoria reacted positively with the antiserum produced against this pathovar but not that produced with pv. translucens. Samples of supernatants from boiled lesions reacted with similar intensity as those from homogenized tissues.
The phosphoenolpyruvate: sugar phosphotransferase system of Streptococcus salivarius. Identification of a IIIman protein
Authors: Vadeboncoeur Christian , Gauthier Lucie
Published: May 2010

A double-spontaneous mutant resistant to the growth inhibitory effect of α-methylglucoside and 2-deoxyglucose was isolated from Streptococcus salivarius. This mutant strain, called αS3L11, did not grow on mannose and grew poorly on 5 mM fructose and 5 mM glucose. Isolated membranes of strain αS3L11 were unable to catalyse the phosphoenolpyruvate-dependent phosphorylation of mannose in the presence of purified enzyme I and HPr. Addition of dialysed membrane-free cellular extract of the wild-type strain to the reaction medium restored the activity. The factor that restored the phosphoenolpyruvate–mannose phosphotransferase activity to membranes of strain αS3L11 was called IIIman. This factor was partially purified from the wild-type strain by DEAE-cellulose chromatography, DEAE-TSK chromatography, and molecular seiving on a column of Ultrogel AcA 34. This partially purified preparation also enhanced the phosphoenolpyruvate-dependent phosphorylation of glucose, fructose, and 2-deoxyglucose in strain αS3L11.
Cytoplasmic silicon in the centric diatom Thalassiosira pseudonana localized by electron spectroscopic imaging
Authors: Rogerson A. , DeFreitas A. S. W. , McInnes A. G.
Published: May 2010

Silicon and phosphorus distributions in the cytoplasm of the diatom Thalassiosira pseudonana were mapped separately using electron spectroscopic imaging techniques. The phosphorus profile delineating cytoplasmic ribosomes overlapped the silicon profile with a high degree of coincidence suggesting a silicon–ribosomal association. Lipid inclusions were also sites of silicon accumulation. The possible significance of these results in wall biomineralization is discussed.
Effect of osmotic potential on synthesis and secretion of polygalacturonase and cellulase by Geotrichum candidum
Authors: Davis L. L. , Baudoin A. B. A. M.
Published: May 2010

In liquid cultures of Geotrichum candidum, amended with KCl, mannitol, or polyethylene glycol 400 to control osmotic potential, levels of both intracellular and extracellular endopolygalacturonase fell off rapidly with decreasing osmotic potential in the range of −0.5 to −2.5 MPa. Concentrations (units per millilitre) of intracellular endopolygalacturonase were higher than those of extracellular endopolygalacturonase at all osmotic potentials tested. The ratio of intracellular to extracellular endopolygalacturonase concentration increased with decreasing osmotic potential; this became most pronounced below −1.5 MPa. It appeared that the major effect of osmotic potential was on endopolygalacturonase synthesis with a minor effect on endopolygalacturonase secretion from the cell. Levels of intracellular and extracellular cellulase also decreased with decreasing osmotic potential, although the effect was much smaller than with endopolygalacturonase. However, the ratio of intracellular to extracellular cellulase concentration did not change significantly with changes in osmotic potential. This indicated that only the synthesis of cellulase was affected.
Alteration of the protein synthesis pattern in Neurospora crassa cells by hyperthermal and oxidative stress
Authors: Kapoor M. , Lewis J.
Published: May 2010

Neurospora crassa cells, grown at 28 °C for 14 h and heat shocked at 48 °C for 45 min, showed the synthesis of 11 heat-shock proteins (nHSPs) in one-dimensional electrophoretic profiles. Treatment with sodium arsenite induced the synthesis of two heat-shock proteins, nHSP70 and nHSP80, and a third, arsenite-specific protein, not induced by hyperthermia. Exposure to 0.5 or 1.0 mM H2O2 led to the induction of two of the heat-inducible nHSP70 family polypeptides. Sodium selenite, used in concert with H2O2, and arsenite were observed to modulate that heat-shock response. In addition, H2O2, menadione, and the glutathione depleters diamide and diethyl maleate promoted the synthesis of another protein, designated oxidative stress-responsive protein (OSP). A DNA-binding protein, specific for Neurospora DNA, was also demonstrated in extracts of heat-shocked cells.
Polydnavirus replication and tissue organization of infected cells in the parasitic wasp Diadegma terebrans
Authors: Krell Peter J.
Published: May 2010

Female parasitic wasps of the species Diadegma terebrans produce a polydnavirus, DtPV, in cells of the calyx. The virus morphology is similar to that of other polydnaviruses. It has a segmented superhelical DNA genome with an estimated size range of 2.3 to 5.5 kilobases. DtPV replication starts within large nuclei where nucleocapsids assemble and become enveloped. They bud through the nuclear envelope and are then "secreted" through the apical microvilli into either the calyx lumen directly or into a channel which is continuous with the lumen. DtPV-producing cells are distributed throughout the length of the calyx and form a discrete, one cell thick "tissue" within it. The large, sector-shaped, DtPV-producing cells form a semicircle around the calyx lumen near the ovariole end of the calyx. This semicircle of DtPV-infected cells increases in circumference towards the lateral oviduct end of the calyx until they completely encircle the lumen and form the major component of the calyx wall.
Subspecificity determination of HBsAg by radioimmunoassay
Authors: Chaudhary R. K. , Knelsen L.
Published: May 2010

A radioimmunoassay method for subtyping hepatitus B surface antigen (HBsAg) was developed. Polystyrene beads pretreated with glutaraldehyde and coated with monospecific anti-d or anti-y antibodies were used. The treatment of beads with glutaraldehyde significantly increased the sensitivity of the test. Subtyping by radioimmunoassay was found to be more sensitive than by the immunodiffusion method. Fifty-nine percent of the samples tested could be subtyped by RIA and only 32% by immunodiffusion. The technique has the added advantage of utilising a commercially iodinated anti-HBs.
Characterization of two abundantly expressed constitutive genes of Neurospora crassa
Authors: Frank Ronald L. , Marzluf George A.
Published: May 2010

Two abundantly expressed, constitutive genes of Neurospora crassa were isolated during differential screening of Neurospora genomic libraries. The coding regions of these two genes, designated RLF1 and RLF3, were identified by hybridization of the cloned DNA sequences with cDNA probes made from polyadenylated RNA. The RLF3 gene was carried on a 15-kilobase Neurospora BamHI DNA fragment present in a lambda 1059 recombinant; a 2-kilobase restriction fragment that contains RLF3 was subcloned into plasmid pBR322 prior to further characterization. Southern blot analysis revealed that both RLF1 and RLF3 are single copy genes. Northern blot analysis and S1 nuclease mapping demonstrated that RLF1 is transcribed to yield a 1.6-kilobase RNA, whereas RLF3 appears to give rise to two distinct sized RNA species of 1.0 and 1.6 kilobases. RNA dot blot analysis provided conclusive evidence that both of these genes are constitutively expressed. These constitutive genes will be valuable to provide a detailed comparison with the 5′ flanking regions of regulated genes.
Changes in plasmodial pigments of Physarum polycephalum in relation to the age of the culture
Authors: Rakoczy Leokadia , Majcherczyk Andrzej , Hüttermann Aloys
Published: May 2010

Plasmodia of the myxomycete Physarum polycephalum were grown in the dark on a semidefined medium and pigments were assayed from cultures of different ages. The absorption of the crude pigment extracts, measured at the maximum, increased with an increase in the growth rate of the organisms, but with a time lag of about 2 days when compared to increases in the plasmodial protein content. Anaylses of pigments were performed with a newly elaborated HPLC method, and eight pigments, monitored at 382 m, were obtained from the different aged plasmodia. Throughout the culture, quantitative changes in the pigments were found which could be described as periodical. Individual pigments varied in their quantitative changes. In prolonged culture the amount of two pigments significantly increased, in comparison with the other colored compounds, and attained their maximum values after plasmodial growth ceased.
Characterization by pyocine typing and serotyping of oral and sputum strains of Pseudomonas aeruginosa isolated from cystic fibrosis patients
Authors: Komiyama Kunio , Habbick Brian F. , Martin Tom , Tumber Satwant K.
Published: May 2010

Oral and sputum isolates of Pseudomonas aeruginosa in patients with cystic fibrosis were investigated. Of the 17 patients studied, 12 patients (71%) yielded both mucoid and nonmucoid variants of Pseudomonas aeruginosa from sputum and (or) various oral ecological sites, such as buccal mucosa, tongue dorsum, dental plaques, and saliva. A total of 51 strains of mucoid and nonmucoid Pseudomonas aeruginosa were isolated from these patients and were phenotypically characterized by both pyocine typing and serotyping. Five patients (42%) were colonized or infected by a single strain of Pseudomonas aeruginosa, whereas 7 patients (58%) were cocolonized or coinfected by two or more phenotypically different strains of Pseudomonas aeruginosa. To understand the mechanisms involved in Pseudomonas aeruginosa colonization, it may be necessary to identify multiple isolates of Pseudomonas aeruginosa not only from the sputum but also from the various oral ecological sites and to further explore the role of the oral cavity in this colonization.
Capacités dégradatives de bactéries et de champignons isolés d'un sol contaminé par un fuel
Authors: Oudot J. , Fusey P. , Abdelouahid D. E. , Haloui S. , Roquebert M. F.
Published: May 2010

The long-term influence of a fuel spill on the bacterial and fungal communities of an agricultural soil was studied. Three years after the contamination, biodegradation of the fuel in the soil was achieved and after 5 years the residual compounds had no significant effect on the density and the specific composition of the microbial populations of the soil. Hydrocarbon-oxidizing bacteria Corynebacterium and Nocardia spp. were isolated. Most of the active fungi were Aspergillus and Penicillium spp., but strains of Paecilomyces, Acremonium, Fusarium, and Gliocladium were also identified. In laboratory experiments, the biodegradation rate of a reference crude oil by pure cultures of oil-degrading strains was nearly the same as in mixed cultures. The biodegradation potential of the strains isolated from the control plot was as high as strains isolated from the oiled plot. In the soil, as in laboratory cultures, the saturate hydrocarbons were more degraded than the aromatics, whereas the resins and asphaltenes were resistant to microbial attack, as were polycyclic alkanes steranes and triterpanes. Nocardia degraded preferentially the aromatics and attacked significantly the asphaltenes, as did Fusarium oxysporum. Aspergillus niger, Aspergillus flavus, and Fusarium oxysporum degraded part of the resins. The spectrum of the initial degradation of petroleum by the most active fungi and bacteria was identical, and it appears that the enzymatic equipment necessary to oxidize hydrocarbons is quite complete in these strains.
Interactions between Treponema bryantii and cellulolytic bacteria in the in vitro degradation of straw cellulose
Authors: Kudo H. , Cheng K.-J. , Costerton J. W.
Published: May 2010

To assess the contribution of individual bacterial species to the overall process of cellulose digestion in the rumen, cellulolytic bacteria (Bacteroides succinogenes and Ruminococcus albus) were tested as pure cultures and as cocultures with noncellulolytic Treponema bryantii. In studies of in vitro barley straw digestion, Treponema cocultures surpassed pure cultures of the cellulolytic organisms in dry matter disappearance, volatile fatty acid generation, and in the production of succinic acid, lactic acid, and ethanol. Morphological examination, by electron microscopy, showed that cells of T. bryantii associate with the plant cell wall materials in straw, but that cellulose digestion occurs only when these organisms are present with cellulolytic species such as B. succinogenes. These results show that cellulolytic bacteria interact with noncellulolytic Treponema to promote the digestion of cellulosic materials.