bluuebunny/crossref_metadata_2025 huggingface dataset:
Elimination of human enteric viruses during conventional waste water treatment by activated sludge
Authors: Payment Pierre , Fortin Sylvie , Trudel Michel
Published: May 2010

The present study was undertaken to determine if viruses were selectively eliminated during waste water treatment. Human enteric viruses were detected at all steps of treatment in a conventional activated sludge waste water treatment plant. Liquid overlays and large volume sampling with multiple passages on BGM cells permitted the detection of poliovirus (serotypes 1, 2, and 3), coxsackievirus B (serotypes 1, 2, 3, 4, and 5), and echovirus (serotypes 3, 14, and 22), as well as reoviruses. The mean virus concentration was 95.1 most probable number of infectious units per litre (mpniu/L) in raw sewage, 23.3 in settled water, 1.4 in effluent after activated sludge treatment, and 40.3 mpniu/L in sludge samples. All samples of raw sewage and settled water, 79% of effluent water, and 94% of sludge samples contained viruses. The mean reduction was 75% after settling and 98% after activated sludge treatment. Poliovirus type 3 was rarely isolated after the activated sludge treatment, but was still detected in about one-third of the sludge samples. Reoviruses and coxsackieviruses were detected at similar rates from all samples and appear to be more resistant to the activated sludge treatment than poliovirus type 3. Poliovirus types 1 and 2 were present in almost every sample of raw sewage and settled water and still found in about half of the effluent and sludge samples, indicating a level of resistance similar to that of reoviruses and coxsackieviruses.
Antigenic analysis of Giardia duodenalis strains isolated in Alberta
Authors: Wenman W. M. , Meuser R. U. , Wallis P. M.
Published: May 2010

Giardia duodenalis is a common intestinal parasite in most parts of the world. In Canada it is associated with both endemic and epidemic infections that are often transmitted by the waterborne route. Although G. duodenalis strains have been isolated from several animals, the role of other mammals in human infection is unclear. We have isolated and cultured G. duodenalis trophozoites from domestic and wild animals in Alberta and compared them with a human isolate by protein gel electrophoresis and immunoblot analysis. All strains examined share a similar polypeptide profile and important protein antigens. Prominent antigens of 62, 52, 38, and 31 kilodaltons are conserved. The 52- and 31-kilodalton proteins are the major surface-exposed trophozoite components. The high degree of antigenic sharing among strains from different hosts suggests that there may be a wide range of potential reservoirs for G. duodenalis infections.
Development and application of a bioassay to study the effects of nutrients, pH, and active substances on Sordaria macrospora fruiting
Authors: Roure Myriam , Bouillant Marie-Louise
Published: May 2010

The perithecial development of Sordaria macrospora (Auersw.) is prevented by ammonium salts as nitrogen source, but only below a critical initial pH in the culture medium. Around this point, a very small variation in the initial pH can induce a morpho-genetic change. Within the inhibition range, supplementation of the culture medium with aqueous cell-free extracts from the fruiting mycelia or fruiting bodies of some fungi overcomes the ammonium inhibition. This phenomenon was used to develop a biological test which could be used to isolate, for the determination of their chemical structure, active fungal substances. The precise physiological conditions required to obtain good reproducibility and reliability with this bioassay have been established, which allows the important effects of nutrients and pH on S. macrospora fruiting to be determined. An application is described with the isolation and characterization of hercynine, an active substance purified from Agaricus bisporus fruiting bodies. Its activity is compared with that of other basic substances.
Purification and physical properties of glucokinase from Thiobacillus versutus (A2)
Authors: Klein David P. , Charles A. Michael
Published: May 2010

Glucokinase was purified 749-fold from Thiobacillus versutus. Polyacrylamide gel electrophoresis revealed the presence of five protein bands in the purified preparation. The purified enzyme retained its original activity after 4 weeks of storage at −20 °C, but not at higher temperatures. Glucose provided some protection at 25 °C. The optimum temperature for activity was between 20 and 25 °C, and an energy of activation (Ea) of 1.305 kcal/mol was calculated. A Q10 value of about 1.080 was determined over two 10 °C temperature ranges between 5 and 20 °C. With both Hepes and Tricine buffers, the optimum pH was 7.8. The enzyme was specific for glucose, with a Km of 0.86 mM. The most efficient phosphoryl donor was ATP with a Km of 0.78 mM. About 30% of the activity observed with ATP was obtained with equimolar amounts of ITP, while TTP and UTP gave 7.0 and 12%, respectively. The enzyme displayed an absolute requirement for a divalent cation, with Mg2+ (Km, 0.27 mM) being the most effective.
Bactericidal action of carbon dioxide laser radiation in experimental dental root canals
Authors: Zakariasen Kenneth L. , Dederich Douglas N. , Tulip John , DeCoste Sandra , Jensen Susan E. , Pickard Michael A.
Published: May 2010

The ability of a carbon dioxide laser to sterilize the root canal of human teeth has been investigated. Three oral bacteria, Streptococcus sanguis, Streptococcus mutans, and Actinomyces viscosus, and three other bacteria, Bacillus cereus, Staphyloccus aureus, and Pseudomonas aeruginosa were used as experimental organisms. Exposure of cells on glass slides to laser radiation showed there was little difference in the exposure required to kill these six organisms. Complete recovery of bacteria from the root canal was initially a problem and was only achieved when bacterial manipulations and removal were carried out in rapid succession, within 5 min of inoculation. However, the geometry of the instrumented canal and the laser alignment were major factors in achieving consistent cell death of oral bacteria in the root canals. Using sets of 10 teeth, four repeated exposures of 10 W for 1 s was found to sterilize 4 or more of the teeth.
Electron microscopic observations of infection threads in driselase treated nodules of Astragalus sinicus
Authors: Higashi Shiro , Kushiyama Kazuya , Abe Mikiko
Published: May 2010

The morphological characteristics of infection threads in the root nodules of Astragalus sinicus were examined by scanning and transmission electron microscopy. The infection threads, epidermal cell walls, and vascular bundles of the nodule were not altered when a nodule was treated with driselase (a plant cell wall degrading enzyme), although the cell walls of meristematic and bacteroid-including zones were completely decomposed by the enzyme treatment. Some infection threads were funnel shaped at the site of attachment of the infection thread to the host cell wall.
Purification of isopenicillin N synthetase from Streptomyces clavuligerus
Authors: Jensen Susan E. , Leskiw Brenda K. , Vining Leo. C. , Aharonowitz Yair , Westlake Donald W. S. , Wolfe Saul
Published: May 2010

Isopenicillin N synthetase was purified from Streptomyces clavuligerus by sequential salt precipitation, ion-exchange and gel-filtration chromatography using both conventional open column and high-performance liquid chromatographic techniques. Material from the final purification step had a specific activity of 204.1 × 10−3 units/mg of protein which represented a 130-fold purification over the cell-free extract. The purified isopenicillin N synthetase was determined to have a molecular weight of 33 000 by sodium dodecyl sulfate – polyacrylamide gel electrophoresis and to have a Km of 0.32 mM with respect to its substrate δ-(L-α-aminoadipyl)-L-cysteinyl-D-valine. The enzyme showed a sensitivity to thiol-specific inhibitors with N-ethylmaleimide giving the strongest inhibitory effect.
Metabolism of rhamnose and other sugars by strains of Clostridium acetobutylicum and other Clostridium species
Authors: Forsberg Cecil W. , Donaldson Lindsay , Gibbins L. N.
Published: May 2010

Twenty-two strains of Clostridium species, including 7 each of Clostridium acetobutylicum and C. butylicum, grew well when supplied with common hexose and pentose carbohydrates as sole carbon sources. Glucosamine and galacturonic acid were used by most strains, but glucuronic acid supported the growth of relatively few. Rhamnose was used, to various degrees, by all strains tested, but less acid was produced than observed from other carbohydrates. The major fermentation products from rhamnose included acetic acid, propionic acid, butyric acid, n-propanol, and 1,2-propanediol. Fermentation product concentration in batch culture was enhanced by inclusion of bicarbonate in the medium. With either arabinose or pyruvate as the source of carbohydrate, supplementation of the medium with 1,2-propanediol resulted in its conversion to propionic acid and n-propanol. With glucose as the carbohydrate source the conversion of 1,2-propanediol to propionic acid and propanol was repressed.
The effect of some culture maintenance and inoculum development techniques on solvent production by Clostridium acetobutylicum
Authors: Gutierrez Noemi A. , Maddox Ian S.
Published: May 2010

An investigation was made into some methods of culture maintenance and inoculum development procedures by which the production of solvents by Clostridium acetobutylicum could be maximized. Storage of the organism as spores in nonnutrient media at either 4 or −20 °C proved to be the most effective method of culture maintenance. On revival of stock cultures, neither heat shocking nor treatment with aqueous ethanol or butanol gave improvements in solvent production during the subsequent fermentation. However, significantly improved production was obtained when culture transfers during the inoculum development procedure were made at the time of maximum cell motility.
ICMSF methods study. XVII. An international comparative study of the direct plate and hydrophobic grid-membrane filter methods for enumeration of Escherichia coli in foods
Authors: Sharpe A. N. , Rayman M. K. , Malik N. , Beckers H. J. , Delfgou E. , Christian J. H. B. , Eyles M. , Dodsworth P. , Nafziger M. , Gibbs P. A. , Whitehead E. , Lanier J. M. , McLaughlin S. , O'Connor F. , Smith L. R. , McLeish D. , Malcolm S.
Published: May 2010

Eight laboratories compared counts of Escherichia coli from naturally or artificially contaminated ground beef, other meats and poultry, vegetables, fish and shellfish, cheese, and diverse sources such as swabs, by the Anderson–Baird-Parker direct plate (DP) and a hydrophobic grid-membrane filter (HGMF) method. For five of the eight laboratories overall counts by HGMF were significantly low (51–83%) compared with those by DP. Counts by HGMF tended to be lower for naturally contaminated samples; several possible causes were investigated. In a subsidiary study, analyst variation in counting HGMF ranged from 0.8–7.3%, with little evidence of effects from counting positive versus negative grid cells or from the fullness of growth or staining intensity.
Synthesis of β-glucan by cell-free extracts of Aureobasidium pullulans
Authors: Finkelman Malcolm A. J. , Vardanis Alex
Published: May 2010

A cell-free system catalysing the synthesis of β-glucan from uridine-diphosphoglucose was prepared from Aureobasidium pullulans. The activity was stable in the presence of 1 M sucrose and 10 mM MgSO4. The polymer produced was insoluble in H2O or acetic acid (0.5 M) and soluble in NaOH (0.5 M). Several enzyme preparations containing β-glucanase activity degraded the polymer to various extents. Synthesis of the polymer was enhanced by the presence of cellobiose and bovine serum albumin, but not by NaF or ATP. A Lineweaver–Burke plot of enzyme activity versus substrate concentration revealed biphasic kinetics. The enzyme preparation was subject to partial activation by trypsin and chymotrypsin.
Differentiation of the cell wall of Azospirillum brasilense
Authors: Murray R. G. E. , Moyles D.
Published: May 2010

Cells of Azospirillum brasilense, growing in both nitrogen-sufficient and nitrogen-deficient media, showed little or no cell wall differentiation at 22 °C, minimal differentiation at 37 °C except after 1 week of incubation, and abundant differentiation after 1 to 2 days at 40 °C. An extra layer appeared outside of the outer membrane of the cell wall of the vibroid cell and showed dentate projections on its inner side. The layer thickened with time of incubation and the inside projections became more prominent. A proportion of cells showed transition to a thick-walled cyst form. The potentiation of differentiation by temperatures between 37 and 40 °C should assist biochemical studies of the phenomenon and in nature should contribute to the development of dessication-resistant forms when soil temperatures rise.
Cell wall alterations in staphylococci growing in situ in experimental osteomyelitis
Authors: Costerton J. W. , Lambe Jr. D. W. , Mayberry-Carson K.-J. , Tober-Meyer B.
Published: May 2010

When cells of both Staphylococcus aureus and Staphylococcus epidermidis are grown in batch culture in nutrient-rich media, their cell walls are regular in thickness, their cell size is within the normal range for each species, and their septation patterns are orderly. When cells of each of these species are examined directly in infected tissue in the rabbit tibia model infection, their cell wall thickness is often much increased and very irregular around the circumference of the cell, their cell size is often increased, and their septation patterns are often severely deranged. All of these alterations in cell wall structure occur in the absence of antibiotics, and we suggest that they may be an expression of phenotypic plasticity in response to altered environmental conditions such as specific nutrient limitations, the presence of antibacterial factors, and growth of the cells on hard surfaces such as rabbit bone or plastic catheters. Some of these specific cell wall alterations are also seen when staphylococcal cells are exposed, in vitro or in vivo, to antibiotics such as clindamycin, but we emphasize that growth in tissue alone is sufficient for their induction.
Oligonucleotide probes for the detection of TEM-1 and TEM-2 β-lactamase genes and their transposons
Authors: Ouellette Marc , Rossi John J. , Bazin Renée , Roy Paul H.
Published: May 2010

We describe the use of molecular probes to detect the TEM-type β-lactamase genes. As a general probe, we prepared a 656 base pair restriction fragment, entirely within the TEM structural gene. This probe was specific for the TEM family, hybridizing only with TEM-1 and TEM-2. The TEM-1 and TEM-2 β-lactamases differ by only one amino acid. We synthesized two oligonucleotides whose central bases correspond to this difference. The use of these oligonucleotides enables us to discriminate between TEM-1 and TEM-2 genes. Using oligonucleotides homologous to parts of Tn3, we also monitored the presence of TnA-like transposons in bacteria harboring different β-lactamase genes. Only the TEM-1 and TEM-2 genes were found to be on transposons with terminal sequences identical to those of Tn3. All hybridization experiments were performed with both dot-blot and colony-hybridization techniques, and the suitability of these two methods for epidemiological studies is compared.
Effects of the pesticides maneb and carbaryl on the phylloplane microflora of lettuce
Authors: Mercier Julien , Reeleder R. D.
Published: May 2010

The effects of the fungicide maneb and the insecticide carbaryl on the microflora of lettuce leaves were studied in field plots in 1983 and 1984. In 1983, populations of filamentous fungi were significantly, but temporarily, reduced by a single application of maneb. This treatment did not reduce populations in 1984; however, two additional applications of maneb did result in a significant decline in fungal populations when compared with unsprayed plants. Maneb had no effect on bacterial populations in either year. Carbaryl altered neither bacterial nor fungal populations. Pesticide applications did not change the composition of the microflora. Phoma and Fusarium spp. were the fungi most frequently isolated from lettuce leaves.
S layer studies on three species of Methanococcus living at different temperatures
Authors: Nußer Elisabeth , König Helmut
Published: May 2010

The cell envelopes of three species of Methanococcus with growth optima within the mesophilic, thermophilic, and extremely thermophilic temperature range were investigated. Methanococcus vannielii, Methanococcus thermolithotrophicus, and Methanococcus jannaschii possess surface layers of hexagonally arranged protein subunits. Glycosylated proteins were not found. The main surface layer proteins of the three species have different molecular weights, which can be taken as additional taxonomic markers. The amino acid composition of the main surface layer proteins shows no significant differences. The acidic amino acids exceed the basic amino acids and the nonpolar amino acids are predominant.
Antibiotic-resistant Pseudomonas in bottled drinking water
Authors: Duquino Helda Hernandez , Rosenberg Fred A.
Published: May 2010

Eight different bottled drinking waters were tested weekly over an 8-month period to determine the diversity of their Pseudomonas population and their sensitivity to eight antibiotics used in treating Pseudomonas infections. Nine species of Pseudomonas were recovered, with P. stutzeri (24%) and P. diminuta (18.8%) being the most common isolates. Sensitivity patterns of environmental and clinical isolates were shown to differ to some degree. Statistical analyses indicated a significant effect of specific antibiotic on the size of the inhibition zone, a significant difference between species and size of inhibition zone, and a strong species–antibiotic interaction. Distribution of species within the brands of water was also significantly different in 68% of the paired comparisons.
Quantum thermodynamics approach to phosphorylation and heterotrophic growth yields
Authors: Tran Van Dan
Published: May 2010

A model of cell growth is presented which is based on the double postulates of quantized loss of energy during phosphorylation and reversible biosynthesis of cell structure. An immediate consequence of the postulates is the identical value for the energy efficiency of the phosphorylation and for that of the whole growth process. Another consequence is the relationship between the energy level of the biomass and the phosphorylation potential as embodied in the equation: [Formula: see text] where EO is the heat of transfer of a pair of electrons to oxygen, EAtp, the molar heat of hydrolysis of ATP, and [Formula: see text], the degree of reduction of the biomass, γM being constant and equal to 5. The model predicts five levels of growth yields corresponding to five permissible values for the P/O ratio (r = 0, 1, 2, 3, and 4). Any growth process would be characterized by a set of two integers N and λ; N is the maximal P/O ratio prescribed by the energy content of the substrate as compared with that of the biomass, and λ the number of further downward quantum jumps of the P/O ratio resulting from the adversity of the growth condition (N − λ = r). Under full aerobiosis, one has 0 ≤ λ ≤ N ≤ 3. When growth is limited only by the energy content of the substrate (λ = 0), the time-independent dispersion of N, owing to substrate-level phosphorylations and (or) dephosphorylations, leads to effective values which are higher than the nominal ones for the yield per mole of oxygen and the heat of transfer of a pair of electrons. Under adverse conditions (λ > 0), the apparent variations of the yields and the P/O ratio in function of the growth rate are shown to be an effect of the random dispersion of λ and of the existence of a maximal rate of substrate consumption. Statistical evidence for the macroscopic quantum effect in heterotrophic growth is presented.
Identification and characterization of insertion sequence ISRm1 in Rhizobium meliloti JJ1c10
Authors: Wheatcroft Roger , Watson Robert J.
Published: May 2010

ISRm1, an insertion sequence present in Rhizobium meliloti strain 1021, has been identified as the cause of the Nod− phenotypes in two mutants of another strain, JJ1c10. The insertions were found to be at different sites, though only about 100 base pairs apart within the nodC gene. ISRm1 causes no mutations in the nifHDK gene region of strain JJ1c10, as it does at high frequency in strain 1021. In JJ1c10 ISRm1 inserted at high frequency into a region of the genome adjacent to copies of other reiterated DNA segments. The target region was not required for symbiotic nitrogen fixation.
Some aspects of the regulation of pyruvate kinase levels in Neurospora crassa
Authors: Devchand Medhavinee R. , Kapoor M.
Published: May 2010

Pyruvate kinase levels were monitored in Neurospora crassa mycelium (grown on different carbon sources for varying time intervals) by immunoprecipitation using polyclonal antibodies raised against a purified enzyme preparation. Pyruvate kinase specific mRNA was demonstrated by hybridization of Northern and dot blots of total RNA with a N. crassa pyruvate kinase gene fragment. Two pyruvate kinase specific mRNA species were detected in mycelia of all ages examined. An age-dependent and carbon source dependent variation in the pyruvate kinase protein and mRNA levels was encountered: (i) both registered an increase for up to about 20 h and a subsequent decline; (ii) growth on acetate and sucrose resulted in significantly higher yields of both, relative to that on medium containing ethanol and alanine. Stress caused by heat shock depressed the pyruvate kinase mRNA levels.
Antibiotic activity of the pyrenocines
Authors: Sparace Salvatore A. , Reeleder Richard D. , Khanizadeh Shahrokh
Published: May 2010

Pyrenocine A, a phytotoxin produced by Pyrenochaeta terrestris (Hansen) Gorenz, Walker and Larson, possesses general antibiotic activity against plants, fungi, and bacteria. Effective doses for 50% inhibition (ED50s) are 4 μg/mL for onion seedling elongation; 14, 20, 20, and 25 μg/mL for the germination of asexual spores of Fusarium oxysporum f. sp. cepae, Fusarium solani f. sp. pisi, Mucor hiemalis, and Rhizopus stolonifer, respectively. Pyrenocine A also inhibits the linear mycelial growth of both P. terrestris and F. oxysporum with ED50s calculated as 77 and 54 μg/mL, respectively. Gram-positive bacteria are more susceptible to pyrenocine A than Gram-negative bacteria. ED50s are estimated as 30, 45, and 200 μg/mL for the inhibition of growth of Bacillus subtilis, Staphylococcus aureus, and Escherichia coli, respectively, with Pseudomonas aeruginosa resistant to those concentrations tested. Pyrenocine A acts primarily as a biostatic rather than a biocidal agent with all organisms tested showing some degree of recovery when released from pyrenocine A. Pyrenocines B and C show little antibiotic activity in the bioassays performed.
Effect of rifampin resistance on nodulating competitiveness of Rhizobium meliloti
Authors: Lewis D. M. , Bromfield E. S. P. , Barran L. R.
Published: May 2010

An assessment was made of the effect of high concentration rifampin resistance on the nodulating competitiveness of five strains of Rhizobium meliloti. The results indicate that the acquisition of rifampin resistance by R. meliloti is generally associated with a significant loss of nodulating competitiveness and an altered RNA polymerase insensitive to the action of rifampin. All mutants were similar to their parent strains with respect to growth rates, phage sensitivity patterns, and symbiotic effectiveness. The data suggest that rifampin resistance in R. meliloti is unsuitable as a marker for ecological studies.
Evidence for a glucose effect on N-acetylglucosamine catabolism in Candida albicans
Authors: Niimi Masakazu , Kamiyama Akiko , Tokunaga Michiko , Nakayama Hiroaki
Published: May 2010

Two strains of Candida albicans were examined for a glucose effect on the catabolism of N-acetylglucosamine. It was shown that the induction of N-acetylglucosamine uptake capacity was almost completely blocked by glucose at 0.5% (w/v), whereas that of N-acetylglucosamine kinase was partially repressed.
Characterization of iron-reducing Alteromonas putrefaciens strains from oil field fluids
Authors: Semple K. M. , Westlake D. W. S.
Published: May 2010

Gram-negative, aerobic bacteria capable of facultative growth using ferric ions or thiosulfate or sulfite as electron acceptors were readily isolated from oil field fluids. Morphological and biochemical data are presented which support the classification of these isolates as being strains of Alteromonas putrefaciens (mol% G + C in the range 42–56%). The isolates expressed a range of halotolerance and temperature tolerance as some would grow in the presence of 7.5% NaCl and some grew well at 4 °C. These physiological characteristics, together with the ability to produce ferrous ions and sulfide and their ubiquitous presence in oil field fluids, indicate that these bacteria could contribute to the corrosion of metal in the oil field environment.
Sulfur isotope fractionation by strains of Alteromonas putrefaciens isolated from oil field fluids
Authors: Semple K. M. , Westlake D. W. S. , Krouse H. R.
Published: May 2010

Strains of Alteromonas putrefaciens which reduce sulfite and thiosulfate to H2S are readily isolated from oil field fluids in north central Alberta. Data are presented on H2S production during anaerobic sulfite reduction by four strains of A. putrefaciens. Analysis of the sulfur isotope composition (δ34S) of the evolved sulfide shows normal and "inverse" isotope fractionation patterns which are diagnostic of dissimilatory sulfite reduction.
Stress proteins and thermotolerance in psychrotrophic yeasts from arctic environments
Authors: Berg Gary R. , Inniss William E. , Heikkila John J.
Published: May 2010

The protein synthetic responses to heat shock of two psychrotrophic yeasts Trichosporon pullulans and Sporobolomyces salmonicolor, isolated from the Arctic, were examined. The temperature of maximum heat shock protein induction was above the maximum temperature for growth in Trichosporon pullulans, but was within the physiological range in Sporobolomyces salmonicolor. Heat shock protein synthetic rates remained elevated in both microorganisms for at least 4 h when the temperature used for heat shock was within the physiological growth range. Both of these nonfermentative yeasts showed a protein synthetic response to recovery from anaerobiosis similar to that shown to heat shock. Trichosporon pullulans failed to show any increased resistance to a lethal thermal stress concomitant with the induction of stress proteins due to heat shock or recovery from anoxia.
Growth promotion of canola (rapeseed) seedlings by a strain of Pseudomonas putida under gnotobiotic conditions
Authors: Lifshitz Ran , Kloepper Joseph W. , Kozlowski Maya , Simonson Catherine , Carlson John , Tipping Elizabeth M. , Zaleska Izabella
Published: May 2010

Inoculation of canola (Brassica campestris) seeds with a nitrogen-fixing strain of Pseudomonas putida (GR12-2) drastically increased the root length of seedlings grown in sterile growth pouches. Seed inoculation with inactive bacteria did not affect root lengths. Root elongation capacity was retained by nonnitrogen-fixing mutants of strain GR12-2. On the other hand, two other wild-type pseudomonads that do not fix nitrogen also increased root elongation. The addition of mineral nitrogen to the growth solution at concentrations of 1 mM or higher significantly inhibited root elongation of either inoculated or noninoculated seedlings. On the other hand, the addition of phosphate to the growth solution at similar concentrations stimulated root elongation of inoculated and noninoculated seedlings. The combined effects of bacterial inoculation and addition of phosphate on root and shoot elongation and on root and shoot weight were additive. Seed inoculation with P. putida GR12-2 increased the uptake of labelled phosphorus (32P) by seedlings grown in growth pouches and also enhanced the shoot elongation of seedlings grown in sterile soil. The capacity of P. putida GR12-2 to enhance phosphate uptake and to promote plant growth under gnotobiotic conditions may open the door to a new direction in the development of plant growth promoting inoculants.
Alterations in lipopolysaccharide produced by chemostat-grown Escherichia coli O157:H7 as a function of growth rate and growth-limiting nutrient
Authors: Dodds Karen L. , Perry Malcolm B. , McDonald Ian J.
Published: May 2010

Escherichia coli O157:H7 was grown in chemostats as continuous cultures at different controlled growth rates and under different nutrient limitations to determine the effects on lipopolysaccharide (LPS) structure. LPS from whole cells and extracted using the hot aqueous phenol method was examined by sodium dodecyl sulfate – polyacrylamide gel electrophoresis (SDS–PAGE) and by gel filtration after hydrolysis with acetic acid. At low growth rates under glucose limitation (D = 0.1 h−1, doubling time (td), approx. 416 min; or D = 0.4 h−1, td, approx. 104 min), E. coli O157 produced high molecular weight LPS identical to that previously characterized from cells grown in batch culture. At a high growth rate (D = 0.8 h−1, td, approx. 52 min), the ratio of high molecular weight LPS to low molecular weight LPS produced greatly decreased. A small amount of high molecular weight LPS, containing O-polysaccharide which lacked amino sugars, and which thus was chemically different from that previously characterized, was produced by the cells at high growth rates. The predominant form of LPS from these cells was of slightly higher molecular weight than rough LPS, probably S–R LPS, and it consistently formed aggregates on SDS–PAGE. This form of LPS was also predominant when E. coli O157 was grown under Mg2+ limitation at an intermediate growth rate (D = 0.4 h−1, td, approx. 104 min).
The incidence of bdellovibrios in an artificial environment: the national aquarium in Baltimore
Authors: Williams H. N. , Toon S. , Faulk E. , Falkler Jr. W. A.
Published: May 2010

The presence of bdellovibrios was established in three aquatic tanks in the National Aquarium in Baltimore and the incidence of the predators was studied. Each of three tanks differed in physical and chemical properties and in the kinds of animal inhabitants. Samples of water, sediment, and bioring surface film were collected from various tanks and were cultured for bdellovibrios and heterotrophic bacteria. The total number of bacteria in the samples was estimated by the direct count method. At the time of sampling, measurements were taken of the water temperature and salinity. Of 12 samples collected periodically from each of two tanks over a 12-month period, bdellovibrios were recovered from 8 samples. In a third tank the predators were recovered from 7 of the 12 samples. Of samples collected daily over a 10-day period from two tanks, bdellovibrios were recovered from one tank each day, but the organisms were not recovered from the second tank during the 10-day period. The predators were recovered more often from water and sediment samples than from samples of the surface film of biorings. With few exceptions, a greater number of the predators were recovered from sediment samples than from samples of water and bioring surface film. From each tank the number of bdellovibrios recovered was observed to fluctuate greatly. The basis for the observed fluctuations was not determined. The incidence of recovery of bdellovibrios from aquarium tanks in this study suggests that the organisms are capable of becoming established as resident flora in an artificial environment such as an aquarium. An aquarium with suitable environmental conditions presents great opportunities to conduct carefully selected studies on the ecology of bdellovibrios in an environment in which certain chemical and physical factors are controlled. Studies of bdellovibrios in controlled environments may lead to a greater understanding of the activities and role of these predators.
Biological suppression of the saprophytic growth of Gaeumannomyces graminis var. tritici in soil
Authors: Simon A. , Sivasithamparam K. , MacNish G. C.
Published: May 2010

The biological suppression of the saprophytic growth of Gaeumannomyces graminis var. tritici in soil in the absence of host roots appeared to be related to suppression of take-all disease of wheat seedlings. When soil collected from a plot which in 1984 and 1985 had grown wheat continuously for 7 and 8 years, respectively, was added at a level of 1% (w/w) to the same soil treated by γ-radiation, saprophytic growth of pigmented hyphae of G. graminis var. tritici on a filter membrane in a soil sandwich was suppressed relative to that occurring in irradiated soil. A soil of the same type from an adjacent area with a history of cereal–pasture alternate rotation did not significantly suppress saprophytic growth of G. graminis var. tritici. Biological suppression of disease of wheat caused by G. graminis var. tritici was tested in a pot bioassay by adding the same two soils, collected in 1985, at a level of 1% (w/w) to fumigated sand infested with oat kernels axenically colonized by the pathogen. Disease severity, measured as the percentage of the seminal root axes with discoloured stele, was reduced by 42 and 6% with the addition of continuous wheat and cereal–pasture rotation soils, respectively, to infested sand, compared with disease severity in unamended, infested sand alone.
Growth-correlated distribution of two types of plasma membrane particles of Schizosaccharomyces pombe
Authors: Takeo Kanji
Published: May 2010

The particle ultrastructure at or near the growing pole and in lateral regions of the plasma membrane of exponential phase Schizosaccharomyces pombe was examined by means of the freeze-fracture technique. The uninvaginated growing pole was predominantly embedded with small globular particles of 4–8 nm in diameter with no depressions. In contrast, densely invaginated lateral regions, where no growth occurs, were rich in large cratered particles of 10–15 nm in diameter with central depressions. On cytokinesis, the middle of the cell near the division furrow became uninvaginated and was predominantly embedded with small globular particles. This is the first report directly concerning the growth-correlated distribution of yeast plasma membrane particles.
Growth of Escherichia coli in a pulp and cardboard mill
Authors: Niemi R. Maarit , Niemelä Seppo , Mentu Juha , Siitonen Anja
Published: May 2010

The coliform flora of a pulp and cardboard mill that uses birch as the raw material and ammonium sulphate as the process chemical was studied. Escherichia coli was observed to multiply in the mill. It persisted as the dominant thermotolerant coliform in the effluent. Klebsiellae were encountered among total coliforms only. The E. coli strains isolated had the biochemical characteristics and maximum growth temperatures typical to the species. However, serotyping and hemolysin test differentiated these strains from pathogenic and fecal E. coli.
Effect of cerulenin and sodium butyrate on chitin synthesis in Candida albicans
Authors: Braun Phyllis C. , Hector Richard F. , Kamark Michael E. , Hart John T. , Cihlar Ronald L.
Published: May 2010

Experiments were conducted to gain insight concerning the mechanism(s) whereby cerulenin and sodium butyrate affect chitin synthesis in Candida albicans. In vitro studies with isolated membrane-bound chitin synthase from C. albicans, strain 4918, showed that neither agent affected the level of either unactivated or trypsin-activated enzyme activity. Subsequent studies utilizing protoplasts revealed that early in the cell wall regeneration process, cells treated with cerulenin or butyrate synthesized chitin at a rate equal to untreated controls, as measured by the incorporation of [3H]-N-acetylglucosamine (GlcNAc) into acid–alkali insoluble material. However, after 40 min of incubation, the incorporation of [3H]GlcNAc into chitin is reduced in cells treated with either agent. On the other hand, samples taken during the same time intervals and analyzed by flow cytometry suggested that the amount of chitin synthesis in treated and untreated cells was identical. A marked decrease in fluorescence was observed in similar experiments using polyoxin D, a direct inhibitor of chitin synthase activity. Experiments that measured uptake of [3H]GlcNAc into both whole cells and protoplasts demonstrated that cerulenin and butyrate had no effect on the transport of the chitin precursor.
Bacillus subtilis Lyt+ and Lyt− strains secrete peptidoglycan hydrolases
Authors: Vitković Ljubiša
Published: May 2010

The phenotypes characteristic of the pleiotropic lytic-deficient Bacillus subtilis mutants have been attributed to reductions in N-acetyl-muramoyl-L-alanine amidase (EC 3.5.1.28) and endo-β-N-acetyl-glucosaminidase (EC 3.2.1.30). It is reported here that these peptidoglycan hydrolases are secreted. The FJ3 (lyt-1), FJ6 (lyt-2), and Nil5 (lyt-15) mutants secreted the enzymes in amounts comparable to a Lyt+ strain. Thus, the Lyt− mutants appear not be as deficient in the enzymes' synthesis as their cell-bound activities indicated. Based on the levels of cell-bound and extracellular activities measured during growth, it is suggested that the Lyt− phenotype may be due to a deficiency of the enzymes' acceptor(s) in cell walls.
Detection and quantitation of human enteric viruses in waste waters: increased sensitivity using a human immune serum globulin–immunoperoxidase assay on MA-104 cells
Authors: Payment Pierre , Trudel Michel
Published: May 2010

This study demonstrates that the most sensitive method for the detection and quantitation of cultivable human enteric viruses in water samples after repassage in the MA-104 cell line is the detection of infected cells by the human immune serum globulin–immunoperoxidase (HISG–IP) method recently described by the authors. This immunoperoxidase method is up to 50 times more sensitive than a liquid overlay assay by cytopathic effect in BGM cells. The viral content of waste waters was evaluated with this new methodology. By this method the average viral content of raw sewage (RS) was 900 mpniu/L (most probable number of infectious units per litre), 1056 mpniu/L in primary effluent (PE), and 106 mpniu/L in secondary effluent (SE). With a cytopathic effect assay on BGM cells, values of 85 (RS), 56 (PE), and 2 (SE) mpniu/L were observed, a striking underestimation of the viral content of secondary effluents.
Second-step reconcentration of environmental samples by ammonium sulfate flocculation of beef extract
Authors: Payment Pierre , Trudel Michel
Published: May 2010

Some enteric viruses are sensitive to the acid environment utilized during the concentration of viruses from water. The use of a neutral flocculant, neutralized ammonium sulfate at 50% saturation, permitted the recovery of 97% of the simian rotavirus SA-11, 87% of Coxsackievirus B-4, and 88% of poliovirus type 1. This method should permit a better recovery of enteric viruses from the environment.
Some N-acyl-D-amino acid derivatives having antibotulinal properties
Authors: Paquet A. , Rayman K.
Published: May 2010

Several N-acyl derivatives of D-tryptophan, D-alanine, D-methionine, D-valine, and D-aspartic acid were synthesized in high yields using the succinimidyl ester method and examined for their antibotulinal properties. In conjunction with 60 ppm of sodium nitrite, sorbyl-D-tryptophan, sorbyl-D-alanine, myristoyl-D-aspartic acid, and glycyl-D-alanine were highly inhibitory. In the absence of sodium nitrite, the N-acyl derivatives of the D-amino acids were not inhibitory. On its own, 60 ppm of sodium nitrite was only slightly inhibitory. Sorbyl-L-tryptophan and sorbyl-L-alanine had no effect in the presence or absence of 60 ppm of sodium nitrite.
Thermostable α-glucosidase produced by Bacillus caldovelox DSM411
Authors: Giblin Mary , Kelly Catherine T. , Fogarty William M.
Published: May 2010

Bacillus caldovelox produces an intracellular α-glucosidase (EC 3.2.1.20). It is the most thermostable microbial α-glucosidase reported to date and a number of its properties are outlined here. It was purified by treatment with protamine sulphate and gel filtration on Sephadex G-150 and gave a single band on SDS–PAGE. The enzyme had highest activity on p-nitrophenyl-α-D-glucoside, which was 2.04 times higher than the activity on maltose, and it was inactive towards isomaltose. It had a molecular weight of 30 000 and an isoelectric point of pH 5.0. The enzyme operated most efficiently at pH 5.5–6.0 and at 50–60 °C. It possessed considerable pH stability, retaining 80% or more activity in the range pH 4.0–9.0. α-Glucosidases tend to be very unstable, but this enzyme was fully stable up to 60 °C for 1 h and retained 51% of its original activity on incubation at 70 °C over the same period. The presence of histidine, cysteine, and manganous ions improved the thermal stability of the enzyme considerably. EDTA, α,α′-dipyridyl, o-phenanthroline, barium, strontium, manganous ions, and glucose stimulated activity, while Tris, ribose, glucono-δ-lactone, and phenyl-α-D-glucoside inhibited activity.
The production of alamethicins by Trichoderma spp.
Authors: Brewer D. , Mason F. G. , Taylor A.
Published: May 2010

The production of polypeptides containing a high percentage of 2-methylalanine residues by a number of isolates of Trichoderma spp. has been examined. It has been shown that good yields (0.5–1.0 g L−1) can be achieved on synthetic media provided an insoluble carbohydrate is included and provided single-spore isolates that have this production ability are selected from time to time. Such yields could not be obtained on any single nitrogen source investigated, but a mixture of potassium nitrate, glutamine, and 2-methylalanine was effective. It was shown that at least eight polypeptides were produced in shake-flask or tank fermentation and that the proportions of these metabolites depended on the fermentation temperature, its pH, age, and aeration. Fermentation conditions for enhancing the production (independently) of two of the metabolites at the expense of the others are given. These two metabolites have been obtained in crystalline form and details of some of their physical and chemical properties are given.
Influence of carbon and nitrogen sources, relative carbon and nitrogen concentrations, and soil moisture on the growth in nonsterile soil of soilborne fungal antagonists
Authors: Stack J. P. , Kenerley C. M. , Pettit R. E.
Published: May 2010

Three components of dispersal important to the colonization of a soil matrix by fungal parasites of sclerotia were identified and measured: the percentage of the carrier granules from which hyphae extended into soil (PGH), the mean number of hyphae extending into soil from each granule (MNH), and the mean length of the hyphae extending into soil (MLH). Factors that influence dispersal were determined for strains of Gliocladium roseum, Thielavia terricola, and Trichoderma spp. The source of carbon, the source of nitrogen, and the C:N ratio of the carrier substrate significantly (p = 0.001) affected all three components of dispersal subsequent to the placement of the carrier granules in nonsterile soil. Increased C:N ratio (12:1 to 80:1) and increased molar concentrations of both carbon and nitrogen sources (0.02 to 0.18 M maltose and 0.006 to 0.024 M arginine) gave increased PGH (17 to 82%), MNH (1 to 5 hyphae per granule), and MLH (275 to 782 μm in 24 h) for G. roseum. Similar increases in PGH (80 to 100%), MNH (5 to 10 hyphae per granule), and MLH (983 μm to too long and interwoven to measure after 24 h) were observed for Th. terricola. PGH and MNH were greater at high soil moistures (−0.1 and −0.33 bars matric potential; 1 bar = 100 kPa) than at low soil moisture (−10 bars).
Effects of temperature upon the cell-free translation system from Coxiella burnetii
Authors: Donahue John P. , Thompson Herbert A.
Published: May 2010

The rate and extent of coliphage Qβ RNA translation by cell-free extracts prepared from Coxiella burnetii were studied. When translations were conducted at temperatures elevated above 37 °C, both polypeptide elongation and frequency of initiation were by comparison increased. The ratios of products synthesized from the polycistronic phage mRNA also changed upon increases in translation temperature, especially at 45 °C. Although the organism is a moderate acidophile, initiation of protein synthesis in extracts did not occur below pH 6.2, and was superior when the pH was 6.8–7.2. The results are discussed in context with the known physiological characteristics of this obligate intracellular bacterium.
Immunoserological studies on root rot of groundnut (Arachis hypogea L.)
Authors: Purkayastha R. P. , Ghosal Anima
Published: May 2010

Antigens obtained from two isolates of Macrophomina phaseolina (Tassi) Goid, a pathogen of groundnut, four non-pathogens of groundnut (viz. Corticium sasakii Shirai (Matsumoto), Colletotrichum lindemuthianum, C. corchori (Pagvi and Singh), and Botrytis alii), and five cultivars of Arachis hypogea L. were compared by immunodiffusion, immunoelectrophoretic, and crossed-immunoelectrophoretic techniques for the presence of cross-reactive antigens. Common antigens were found among the susceptible cultivars of groundnut and two isolates of M. phaseolina, but not between nonpathogens and groundnut cultivars. No antigenic similarity was found between nonpathogens and M. phaseolina isolates. Crossed-immunoelectrophoretic tests confirmed that at least one antigen was common between cv. J-11 and cv. TMV-2, cv. Kadiri 71-1 and cv. TMV-2, and cv. Kadiri 71-1 and isolates of M. phaseolina.
Oxidation of primary bile acids by a 7α-hydroxysteroid dehydrogenase elaborating Clostridium bifermentans soil isolate
Authors: Sutherland J. Derek , Williams C. Noel , Hutchison Donna M. , Holdeman Lillian V.
Published: May 2010

A gram-positive, rod-shaped anaerobe (strain F-6) was isolated from soil. This organism was identified by cellular morphology as well as fermentative and biochemical data as Clostridium bifermentans. Strain F-6 formed 7-ketolithocholic acid from chenodeoxycholic acid and 7-ketodeoxycholic acid from cholic acid in whole cell cultures, but did not transform deoxycholic acid, ursodeoxycholic acid, or ursocholic acid. This reaction is reversible. The structures of 7-ketolithocholic acid and 7-ketodeoxycholic acid were verified by mass spectroscopy and by thin-layer chromatography using Komarowsky's spray reagent. When incubated with the strain F-6 glycine and taurine conjugates of the primary bile acids were partially hydrolyzed and transformed to 7-keto products. Optimal yields of 7-ketolithocholic acid and 7-ketodeoxycholic acid were obtained after 78 h of incubation. Culture pH changed with time and was characterized by an initial drop (1.1 pH units) and a gradual increase back to the starting pH (7.3). Corroborating these observations, an inducible, NADP-dependent, 7α-hydroxysteroid dehydrogenase was demonstrated in cell extracts of strain F-6. A trace of NAD-dependent 7α-hydroxysteroid dehydrogenase was also found. A substantial increase in the specific activity of the NADP-dependent 7α-hydroxysteroid dehydrogenase was observed when either 7-ketolithocholic acid, chenodeoxycholic acid, or deoxycholic acid was included in the growth medium. Optimal induction of the NADP-dependent 7α-hydroxysteroid dehydrogenase was achieved with 0.3–0.4 mM 7-ketolithocholic acid. Production of the enzyme(s) was optimal at 6–8 h of growth and the 7α-hydroxysteroid dehydrogenases had a pH optimum of approximately 11. The 7α-hydroxysteroid dehydrogenase from strain F-6 was purified 12-fold by triazine dye affinity chromatography with reactive blue 2 (Cibacron blue) agarose (95% yield). It was successfully lyophilized into a stable powder form.