bluuebunny/crossref_metadata_2025 huggingface dataset:
Pullulan Elaboration by
Aureobasidium pullulans
Protoplasts
Authors: Finkelman Malcolm A. J. , Vardanis Alexander
Published: January 2020

Protoplasts of
Aureobasidium pullulans
are capable of producing pullulan. Biosynthesis of the polymer pullulan required induction with kinetics similar to those of whole cells. The protoplasts also produced a heteropolysaccharide component containing mannose, glucose, and galactose. The relative proportions of the pullulan and heteropolysaccharide fractions were a function of glucose concentration, with the pullulan content of the total polysaccharide rising from 20% at 2.5 mM glucose to 45% at 20 mM glucose. Elaboration of pullulan by both cells and protoplasts was sensitive to 0.6 M KCl, which was present as the osmotic stabilizer in protoplast experiments. The presence of KCl resulted in a shift in the pH optimum to a more acidic value. The molecular weight of the protoplast-derived pullulan was sharply reduced from the molecular weight of the whole-cell-derived product. Exposure of the protoplasts to proteolytic enzymes had no effect on polysaccharide elaboration.
Effect of Dietary Extremes on Impala (
Aepyceros melampus
) Rumen Epimural Flora
Authors: Hill R. H.
Published: January 2020

The impala, classified as an intermediate feeder among wild ruminants, grazes exclusively on green grasses during the summer rains but turns to an essentially browse habit during the winter, when a diet of leaves, pods, and twigs is supplemented with dried grasses. Scanning electron microscope studies of bacteria attached to the rumen epithelia of animals feeding on digestible, carbohydrate-rich grazing diet showed a high level of surface colonization, with pockets of mixed morphological types occupying spaces vacated by desquamated epithelial cells. Rumen wall colonization in browsing animals on an indigestible, abrasive, low-plane diet showed denudation of distal papillar surfaces with sparse homogeneous adherent flora in the microprotected areas towards the bases. Forage characteristics associated with raised volatile fatty acid concentrations in ingesta, higher rate of epithelial sloughing, and minimum abrasion were interrelated with density and complexity of the adherent bacterial flora.
Succinate-Induced Morphology of
Rhizobium trifolii
0403 Resembles That of Bacteroids in Clover Nodules
Authors: Urban James E. , Dazzo Frank B.
Published: January 2020

Morphological changes which accompany nutrient enrichment of
Rhizobium trifolii
0403 were studied. Assays of cell number and size coupled with scanning electron microscopy and immunofluorescence microscopy showed that succinate induces cells to stop dividing in vitro and to swell either in the cell center or at one cell pole. The extent and frequency of in vitro cell swelling were in direct relation to the concentration of succinate added to the enrichment medium. The in vitro swelling of cells in 16.6 mM succinate plus Casamino Acids, glucose, and yeast extract closely resembled that of bacteroids of
R. trifolii
0403 in nitrogen-fixing nodules of white clover. We hypothesize that succinate may be involved in the transformation of vegetative bacteria into the bacteroid morphology found in nitrogen-fixing nodules.
Generalized Immunoassay for
Autographa californica
Nuclear Polyhedrosis Virus Infectivity In Vitro
Authors: Volkman Loy E. , Goldsmith Phyllis A.
Published: January 2020

A quantitative in vitro immunoassay for the infectivity of
Autographa californica
nuclear polyhedrosis virus was developed and performed in six different lepidopteran cell lines. The assay was not dependent upon cytopathic effect or polyhedron production, but rather upon viral antigen production and its recognition in a peroxidase-antiperoxidase staining procedure. The importance of using such an assay for accurately assessing infectivity in cell lines which produce polyhedra inefficiently was demonstrated. Differences among the cell lines in sensitivity to viral infection were clearly shown. Differences in the time required to produce infectious progeny were also noted among cells of the same cell line.
Growth-Related Substituent Changes in Exopolysaccharides of Fast-Growing Rhizobia
Authors: Cadmus Martin C. , Burton Kermit A. , Slodki Morey E.
Published: January 2020

Pyruvic acid and O-acetyl groups are the major noncarbohydrate substituents in exopolysaccharides (EPS) produced by fast-growing species of
Rhizobium
. EPS substituent variations were observed among strains of the same species. The amounts of these substituents also varied with culture age; pyruvic acid increased in the EPS of all four species, whereas
O
-acetyl increased in
Rhizobium trifolii
and
R. leguminosarum
EPS, decreased in
R. meliloti
EPS, and remained constant in
R. phaseoli
EPS. The use of glycerol as a substrate for
R. meliloti
significantly increased EPS yields, whereas mannitol increased those of the other three
Rhizobium
species.
Plasmid Involvement in Parathion Hydrolysis by
Pseudomonas diminuta
Authors: Serdar Cüneyt M. , Gibson David T. , Munnecke Douglas M. , Lancaster John H.
Published: January 2020

An organism identified as
Pseudomonas diminuta
was found to hydrolyze parathion. Cells grown for 48 h contained 3,400 U of parathion hydrolase activity per liter of broth. Expression of enzymatic activity was lost at a high frequency (9 to 12%) after treatment with mitomycin C. Hydrolase-negative derivatives were missing a plasmid present in the wild-type organism. The molecular mass of this plasmid (pCS1), as determined by electron microscopy, was about 44 × 10
6
daltons.
Formation, Location, and Regulation of Endo-1,4-β-Glucanases and β-Glucosidases from
Cellulomonas uda
Authors: Stoppok Waltraud , Rapp Peter , Wagner Fritz
Published: January 2020

The formation and location of endo-1,4-β-glucanases and β-glucosidases were studied in cultures of
Cellulomonas uda
grown on microcrystalline cellulose, carboxymethyl cellulose, printed newspaper, and some mono- or disaccharides. Endo-1,4-Glucanases were found to be extracellular, but a very small amount of cell-bound endo-1,4-β-glucanase was considered to be the basal endoglucanase level of the cells. The formation of extracellular endo-1,4-β-glucanases was induced by cellobiose and repressed by glucose. Extracellular endoglucanase activity was inhibited by cellobiose but not by glucose. β-Glucosidases, on the other hand, were formed constitutively and found to be cell bound. β-Glucosidase activity was inhibited noncompetitively by glucose. Some characteristics such as the optimal pH for and the thermostability of the endoglucanases and β-glucosidases and the end products of cellulose degradation were determined.
Phenylpropanoic Acid: Growth Factor for
Ruminococcus albus
Authors: Hungate R. E. , Stack Robert J.
Published: January 2020

Phenylpropanoic acid accounted for part of the stimulatory effect of rumen fluid on the rate of growth and of cellulose digestion by cultures of
Ruminococcus albus
strain 8 grown on a chemically defined medium. As little as 3 μM concentration gave maximum response.
Mass Spectrometric Quantification of Indole-3-Acetic Acid in
Rhizobium
Culture Supernatants: Relation to Root Hair Curling and Nodule Initiation
Authors: Badenoch-Jones Jane , Summons R. E. , Djordjevic M. A. , Shine J. , Letham D. S. , Rolfe B. G.
Published: January 2020

Indole-3-acetic acid (IAA) has been unequivocally identified in culture supernatants of
Rhizobium
strains by gas chromatography-mass spectrometry. A method for accurately quantitating IAA in bacterial culture supernatants, employing deuterium-labeled IAA as an internal standard, has been developed. Similar IAA concentrations were found in culture supernatants of chosen
Rhizobium
mutants (defective in nodule formation) and their corresponding parent strains. Since some of the mutants are known to adhere to root hairs, it can be concluded that root hair curling is not simply a consequence of IAA production by rhizobia.
Development of a shaker culture of Buffalo green monkey kidney cells: potential use for detection of enteroviruses
Authors: Goldstein G , Guskey L E
Published: January 2020

Buffalo green monkey kidney cells were adapted to grow as shaker cultures. Replication of environmental and clinical isolates of poliovirus, coxsackievirus, and echovirus in these cultures was analyzed by plaque assay and compared with replication in Buffalo green monkey kidney cell monolayers and HEp-2 cell shaker cultures. Dose-response tests with various concentrations of Mahoney type 1 poliovirus indicated that Buffalo green monkey kidney cell shaker cultures could detect as little as 1 PFU in an inoculum of 0.2 ml. These data suggest that Buffalo green monkey kidney cell shaker cultures can be effectively used for the detection of small quantities of enteroviruses from environmental sources.
Single-Cell Protein Production in Alkaline Mesquite Wood Extracts
Authors: Hsu Chian-Chung , Thayer Donald W.
Published: January 2020

A nine-member, mixed, cellulolytic, bacterial culture was used to evaluate the effects of sodium hydroxide normality, length and temperature of treatment, and the ratio of volume of alkali to mesquite wood on the suitability of alkali mesquite wood extractives as nutrients for bacterial growth. The presence or absence of air during the extraction process did not significantly affect results. The amount of lignin extracted and the total loss in weight of the wood during extraction were correlated to both alkali concentration and temperature. Neutralized extracts supported bacterial growth; growth was inversely related to the final salt concentration of the neutralized extract. Deionized extracts were superior to acid-neutralized extracts for the support of bacterial growth. The optimum conditions for extraction were 2.5 N NaOH at 30°C for 12 h. The study demonstrated that nutrients as well as growth inhibitory compounds are released from wood by alkali treatment. This study of alkali wood extracts and the previous study of washed alkali treated wood residues provide a data base for the optimization of alkali treatments of hard woods that are to be used as nutrients for the growth of cellulolytic cultures.
Fate of virus in wastewater applied to slow-infiltration land treatment systems
Authors: Schaub S A , Bausum H T , Taylor G W
Published: January 2020

The removal of seeded coliphage f2 and indigenous enteroviruses from primary and secondary wastewaters applied by spray irrigation to sandy loam and silt loam soils in field test cells was examined. The amount of f2 recovered from 170-cm-deep soil percolate samples taken over a 53-day period never exceeded 0.1% of applied virus levels and was usually below detection limits. Indigenous enterovirus levels in percolate waters also constituted only a small portion of those found in the wastewaters. At 10 days after seeding, f2 virus was present throughout the soil column but tended to accumulate around the soil core middepths. Coliphage f2 disappeared from the soil surface regions at a high rate, and by 53 days very little virus could be detected within the length of the soil columns. Sterilized soil core segments from different depths were studied to determine their virus adsorption capabilities when suspended in either wastewater, test cell percolate water, or distilled water containing divalent cations. The adsorptive capacity of Windsor and Charlton soils for poliovirus 1 and coliphage f2 increased greatly with the soil sample depth until leveling off at the midcore depths. Soil suspended in wastewater had the least virus adsorption capability for all depths studied.
Effect of pH on growth rates of rumen amylolytic and lactilytic bacteria
Authors: Therion J J , Kistner A , Kornelius J H
Published: January 2020

The relationship between the pH of the medium and specific growth rates, in well-buffered media at 38.5 degrees C, was determined for three strains of Butyrivibrio fibrisolvens and for one strain each of Streptococcus bovis, Selenomonas ruminantium subsp. lactilytica. Megasphaera elsdenii, Veillonella alcalescens, and Propionibacterium acnes. The pH optima for growth were between 6.1 and 6.6 for all six species, and the upper pH limits were between 7.3 and 7.8. The lower limit pH values for growth on glucose were 5.4 for B. fibrisolvens, near 5.0 for V. alcalescens, and between 4.4 and 4.8 for the other four species. These values fall within the minimum pH ranges found when these species are grown in poorly buffered medium with nonlimiting glucose concentrations. Acid sensitivity per se could cause the washout of B. fibrisolvens, but not of the other five species, from the rumens of animals on high-starch diets.
Alteration of the Trifoliin A-Binding Capsule of
Rhizobium trifolii
0403 by Enzymes Released from Clover Roots
Authors: Dazzo Frank B. , Truchet Georges L. , Sherwood John E. , Hrabak Estelle M. , Gardiol Alicia E.
Published: January 2020

The effect of white clover root exudate on capsules of
Rhizobium trifolii
0403 was examined. The clover lectin trifoliin A was detected in root exudate of two clover varieties by indirect immunofluorescence with antibody against this lectin purified from clover seed. Trifoliin A bound uniformly to encapsulated, heat-fixed cells during 1 h of incubation with root exudate. After 4 to 8 h of incubation, trifoliin A was only bound to one pole of the cells. Transmission electron microscopy showed that the capsule itself was altered. The disorganization of the acidic polymers of the capsule began in the equatorial center of the rod-shaped cell and then progressed toward the poles at unequal rates. Trifoliin A could no longer be detected on heat-fixed cells after 12 h of incubation with root exudate. However, trifoliin A was detected in situ on one pole of cells grown for 4 days in the clover root environment of Fahraeus slide cultures. Inhibition studies with the hapten 2-deoxy-
d
-glucose showed that trifoliin A in root exudate had a higher affinity for one of the cell poles. Immunoelectrophoresis was used to monitor the alteration of the extracellular polysaccharides from
R. trifolii
0403 by concentrated root exudate. These polysaccharides were converted into products which eventually lost their ability to immunoprecipitate with homologous antibody. This progressive loss of antigenic reactivity proceeded more rapidly with root exudate from seedlings grown under nitrogen-free conditions than with root exudate from plants grown with 15 mM KNO
3
. The root exudate, depleted of trifoliin A by immunoaffinity chromatography, was still able to alter the capsule of
R. trifolii
0403. Reconstitution experiments showed that the substance(s) in root exudate which induced this alteration of the capsule was of a high molecular weight, heat labile, trypsin sensitive, and antigenically unrelated to trifoliin A. A variety of glycosidase activities were also detected in the fraction depleted of trifoliin A. These results suggest that enzymes in clover root exudate alter the trifoliin A-binding capsule in a way which would favor polar attachment of
R. trifolii
to clover root hairs.
Identification of “Water-Soluble” Toxins Produced by a
Stachybotrys atra
Strain from Finland
Authors: Harrach Balázs , Nummi Martti , Niku-Paavola Marja-Leena , Mirocha Chester J. , Palyusik Mátyás
Published: January 2020

Toxins of a
Stachybotrys atra
strain from Finland proved to be soluble in a simulated gastrointestinal system. They were purified and characterized as satratoxin H, satratoxin G, and an unknown macrocyclic trichothecene with a molecular ion of 528.
Maintenance of Laboratory Strains of Obligately Anaerobic Rumen Bacteria
Authors: Teather Ronald M.
Published: January 2020

Cultures of rumen bacteria can be stored at −20°C for at least 2 years in a liquid medium containing 20% glycerol. Thawing, sampling, and refreezing do not significantly affect viability.
Use of Gentamicin in Axenic Culturing of Ectomycorrhizal Plants
Authors: Kidd Frank A. , Wullschleger Stan D. , Dawley Kathy , Reid C. P. Patrick
Published: January 2020

Gentamicin is inhibitory to bacteria associated with
Pinus
ectomycorrhizae, but does not appear to affect the growth and metabolic activity of the fungus or root.
Comparison of bacterial recovery by Reuter centrifugal air sampler and slit-to-agar sampler
Authors: Placencia A M , Peeler J T , Oxborrow G S , Danielson J W
Published: January 2020

Bacterial recovery by a portable Reuter centrifugal air sampler and a standard Mattson-Garvin slit-to-agar air sampler was compared in a series of experiments. Microbial air quality was monitored in seven typical laboratory locations. Tests showed that the Reuter centrifugal air sampler yielded significantly higher recoveries than did the slit-to-agar unit.
Water disinfection with the hydrogen peroxide-ascorbic acid-copper (II) system
Authors: Ragab-Depre N J
Published: January 2020

Treatment of secondary effluents with hydrogen peroxide (10 mg/liter)-ascorbic acid (10 mg/liter)-Cu2+ (0.5 mg/liter) for 60 min resulted in around 99% reduction of the initial plate count. Hydrogen peroxide could be replaced by other peroxygen compounds; ascorbic acid could be replaced by other reducing agents, of which sodium sulfite and ethanol were the most effective. Cu2+, however, could not be replaced by other metal ions without loss of bactericidal efficiency of the ternary combination. Enterobacteriaceae, total and fecal coliforms, staphylococci, and micrococci were reduced by 99.0 to 99.9%. Group D streptococci aerobic spores were reduced by 80 and 15%, respectively. Clostridium perfringens, yeasts, and molds were not killed by the disinfectant combinations. The effect of pH was only minor in the range from 6 to 7.5. At a higher pH value the bactericidal effects tended to decrease. The hydrogen peroxide-ascorbic acid-Cu2+ combination made it possible to obtain 99% reduction within 30 min. When using the hydrogen peroxide-sodium sulfite-Cu2+ or the hydrogen peroxide-ethanol-Cu2+ combinations, 60 min of contact time was necessary to obtain 99% reduction of the initial plate count. Cu2+ combined to an intermediate product of the ascorbic acid autoxidation is the toxic agent, and its penetration into the cell is promoted by hydrogen peroxide.
Metabolism of the Plasticizer di-
n
-Butylphthalate by
Pseudomonas pseudoalcaligenes
Under Anaerobic Conditions, with Nitrate as the Only Electron Acceptor
Authors: Benckiser G. , Ottow J. C. G.
Published: January 2020

The metabolism of di-
n
-butylphthalate by a denitrifying strain of
Pseudomonas pseudoalcaligenes
B20b1 was studied under anaerobic conditions, with nitrate as the only electron acceptor. Thin-layer chromatography and mass spectral analysis of culture extracts (20 days at 30°C) showed mono-
n
-butylphthalate and phthalic acid as the only products, suggesting that one butanol moiety served essentially as the carbon source for growth and denitrification. N
2
and N
2
O were detected by gas chromatography. In contrast to aerobic metabolism, phthalate was not degraded further if nitrate was the only electron acceptor.
Role of blastospores in protecting Aspergillus parasiticus NRRL 3240 from high levels of aflatoxins
Authors: Bhatnagar R K , Ahmad S , Mukerji K G , Venkitasubramanian T A
Published: January 2020

The role of blastospores in the protection of Aspergillus parasiticus from high levels of aflatoxins was studied. The strain protects itself from aflatoxicity by forming thick-walled blastospores. The formation of blastospores was not observed under conditions of reduced aflatoxin formation, e.g., under zinc and asparagine deficiencies. The germination of blastospores coincided with an increase in the specific activity of glutamate dehydrogenase (NADP) and a simultaneous decrease in the specific aflatoxin production.
Quantitative Study of Nodulation Competitiveness in
Rhizobium
Strains
Authors: Amarger Noëlle , Lobreau Jean Pierre
Published: January 2020

We compared the nodulation competitiveness of three strains of
Rhizobium leguminosarum
by counting the number of nodules formed on faba bean plants after the application at sowing time of different concentrations of the strains to soils already containing
Rhizobium
strains of the same species. A relationship of type
y
= ax

n

was found to exist between the ratio of the nodules formed by the applied inoculum strain to the nodules formed by the soil strains and the ratio of
Rhizobium
cells in the inoculum to the cells in the soil. This relationship was also confirmed in another competition experiment in which two
R. meliloti
strains of identical competitiveness were mixed in various proportions. The relationship can also be applied to the majority of results reported in the literature. Should it prove to be more widely applicable, it could be used to estimate the relative competitiveness of
Rhizobium
strains and thus predict the performance of an inoculum in a given soil.
Increased sensitivity of heat-stressed Saccharomyces cerevisiae cells to food-grade antioxidants
Authors: Eubanks V L , Beuchat L R
Published: January 2020

Unheated and heat-stressed Saccharomyces cerevisiae cells were examined for their relative sensitivities to butylated hydroxyanisole (BHA), tertiary butylhydroquinone (TBHQ), and propyl gallate. Heated cells had significant (P less than or equal to 0.05) increases in sensitivity to 50 micrograms of BHA, 100 micrograms of TBHQ, and 1,000 micrograms of propyl gallate per ml as compared with unheated cells when surface plated on antioxidant-supplemented recovery agar. The rate of increase in size of colonies developed by heated cells was slower than that of unheated cells, and the presence of antioxidants in recovery agar enhanced this effect. Heat-stressed cells also had increased sensitivity to ethanol. Incubation temperatures of 15, 21, 30, and 37 degrees C for enumerating unheated cells had no significant effect on the numbers of colonies formed on unsupplemented recovery agar; however, incorporation of 100 micrograms of BHA, 200 micrograms of TBHQ, or 1,000 micrograms of propyl gallate per ml into agar resulted in significant decreases in the number of colonies formed by heated cells at various incubation temperatures. The detrimental effects of TBHQ and propyl gallate on repair of heat-injured cells are apparently expressed at a temperature higher than that observed for BHA. It is suggested that the adverse effects of antioxidants on repair of heat-injured S. cerevisiae cells may be associated with oxygen availability.
Saccharomyces cerevisiae
Mutants Resistant to Catabolite Repression: Use in Cheese Whey Hydrolysate Fermentation
Authors: Bailey Richard B. , Benitez Tahia , Woodward Anne
Published: January 2020

Mutants of an industrial-type strain of
Saccharomyces cerevisiae
which rapidly and completely fermented equimolar mixtures of glucose and galactose to ethanol were isolated. These mutants fell into two general phenotypic classes based upon their fermentation kinetics and enzyme induction patterns. One class apparently specifically effects the utilization of galactose and allows sequential utilization of first glucose and then galactose in an anaerobic fermentation. The second class of mutants was resistant to general catabolite repression and produced maltase, invertase, and galactokinase in the presence of repressive levels of glucose. These mutants were completely dominant and appear to represent an as yet undescribed class of mutant.
Variations in Ability of
Rhizobium japonicum
Strains To Nodulate Soybeans and Maintain Fixation in the Presence of Nitrate
Authors: McNeil David L.
Published: January 2020

This study investigated differences in sensitivity to nitrate of soybean (
Glycine max
cv. Davis) symbioses with 16 different
Rhizobium japonicum
strains. When nitrate (20 mM) was added to established symbioses, there were no significant differences in the degree of inhibition of acetylene reduction for any of the 16 strains. When nitrate was present during the establishment of nodules, high levels of nitrate (10 mM) were equally inhibitory on all symbioses, whereas specific strain effects appeared at low (0.5 mM) to medium (2.0 mM) levels of nitrate. At 1.5 mM nitrate in solution culture, the days to emergence of nodules varied from less than 10 (CB:1809, Nit61A118) to more than 16 (11 of 16 strains). In a clay-pot trial maintained at the low nitrate level (0.5 mM), symbioses with CB:1809 increased total nodule mass by 30% relative to nitrate-free controls. In the presence of 2.0 mM nitrate, CB:1809 maintained total nodule mass. For the remaining 6 strains tested, total nodule mass decreased to below the levels of the nitrate-free controls. In a separate clay pot trial, CB:1809 increased its competitive ability relative to USDA:110 when nitrate was added. If no nitrate was added, CB:1809 occupied 0.97 times as many nodules as USDA:110; when 10 mM nitrate was added, CB:1809 occupied 1.75 times as many nodules as USDA:110. Attempts to select nitrogen-adapted substrains of
R. japonicum
through sequential isolation and infection of plants grown on nitrate were not successful.
Effect of Sorption on Mineralization of Low Concentrations of Aromatic Compounds in Lake Water Samples
Authors: Subba-Rao R. V. , Alexander Martin
Published: January 2020

Montmorillonite-benzylamine complexes were formed immediately upon addition of 20 pg to 20 μg of amine per ml of suspensions containing the clay. The extent of amine sorbed was a linear function of equilibrium amine concentration in lake water. Increases in the clay concentration decreased the percentage of the organic compound that was mineralized at amine levels of 20 pg to 200 ng, but not at 20 μg/ml. A larger percentage of the chemical was released from the complex during mineralization in the presence of high clay concentrations than in the presence of low clay concentrations. The rates of desorption and mineralization increased linearly with benzylamine levels up to 200 ng/ml. Montmorillonite did not enhance mineralization rates at amine levels of 200 ng/ml or lower, but it was stimulatory at 20 μg/ml. Except at high amine and clay concentrations, mineralization was more rapid than desorption during the early periods of decomposition when the amine concentration in solution was relatively high. However, relative to the microbial demand, desorption was more rapid during later periods of decomposition when the amine level in solution was very low. Mineralization of benzoate was not usually affected by montmorillonite, kaolinite, or glass beads. More than 90% of the carbon from benzylamine and benzoate was often mineralized when the substrate concentration was 250 ng/ml or less. After incubation of the chemical in lake water, none of the radioactivity from benzylamine was in the particulate fraction containing natural sediment and microbial cells. The data indicate that clay may have a significant effect on the microbial decomposition of low concentrations of certain organic compounds.
Stimulation of 3,4-dichloroaniline mineralization by aniline
Authors: You I S , Bartha R
Published: January 2020

Mineralization of free and of humus-bound 3,4-dichloroaniline (DCA) by a Pseudomonas putida strain isolated by analog enrichment was greatly enhanced in the presence of aniline. The addition of aniline to soil that contained 0.2 to 100 micrograms of DCA per g in free or in humus-bound form increased the mineralization rates of DCA severalfold. Within the concentration ranges tested, absolute mineralization of DCA per unit time was positively correlated with both increasing DCA and increasing aniline concentrations. The specific enrichment of microbial populations and the induction of pathways that can co-metabolize DCA are the most plausible explanations for the effect of aniline. The observed phenomenon points to a potential approach for eliminating xenobiotic pollutants from contaminated soils.
Decontaminating infectious laboratory waste by autoclaving
Authors: Lauer J L , Battles D R , Vesley D
Published: January 2020

The temperature profile of infectious laboratory waste being autoclaved was examined relative to the type of containers used in the process. A standardized waste load (1,750 +/- 4 g) placed in the container was evaluated by using a direct readout thermocouple. The sensor of the thermocouple was placed within an unused and outdated agar plate, centrally located about 5 cm from the bottom of the container. The gravity displacement autoclave tested reached 121 degrees C within 3 min. Waste within a steel container (plus 1 liter of water) reached 108, 120, and 122 degrees C at 12, 30, and 50 min, respectively. Without the addition of water, the corresponding temperatures were 60, 110, and 120 degrees C, respectively. With a steel container, "autoclavable" plastic bags, and no additional water, the temperatures were 36, 71, and 105 degrees C, respectively. When 1 liter of water was placed in the autoclavable bag, the temperatures were 98, 115, and 121 degrees C, respectively. Waste within a polypropylene container (dimensions similar to those of the steel container) with and without the addition of 1 liter of water, reached a maximum temperature of 108 degrees C at 50 min. With a polypropylene container, autoclavable plastic bag, and 1 liter of water, the corresponding temperature was 99 degrees C. Without the addition of water, the temperature was 92 degrees C. The importance of container, moisture, and material in autoclaving was demonstrated.
Fate and effects of methylene chloride in activated sludge
Authors: Klecka G M
Published: January 2020

Activated sludge obtained from a municipal wastewater treatment plant was acclimated to methylene chloride at concentrations between 1 and 100 mg/liter by continuous exposure to the compound for 9 to 11 days. Acclimated cultures were shown to mineralize methylene chloride to carbon dioxide and chloride. Rates of methylene chloride degradation were 0.14, 2.3, and 7.4 mg of CH2Cl2 consumed per h per g of mixed-liquor suspended solids for cultures incubated in the presence of 1, 10, and 100 mg/liter, respectively. Concentrations of methylene chloride between 10 and 1,000 mg/liter had no significant effect on O2 consumption or glucose metabolism by activated sludge. A hypothetical model was developed to examine the significance of volatilization and biodegradation for the removal of methylene chloride from an activated sludge reactor. Application of the model indicated that the rate of biodegradation was approximately 12 times greater than the rate of volatilization. Thus, biodegradation may be the predominant process determining the fate of methylene chloride in activated sludge systems continuously exposed to the compound.
Fate in Model Ecosystems of Microbial Species of Potential Use in Genetic Engineering
Authors: Liang Li Nuo , Sinclair James L. , Mallory Larry M. , Alexander Martin
Published: January 2020

The changes in populations of
Staphylococcus aureus, Bacillus subtilis, Salmonella typhimurium, Klebsiella pneumoniae, Agrobacterium tumefaciens, Rhizobium meliloti
, and
Saccharomyces cerevisiae
were measured after their introduction into samples of sewage, lake water, and soil. Enumeration of small populations was possible because the strains used were resistant to antibiotics in concentrations and combinations such that few species native to these ecosystems were able to grow on agar containing the inhibitors. Fewer than 2 cells per ml of sewage or lake water and 25 cells per g of soil could be detected.
A. tumefaciens
and
R. meliloti
persisted in significant numbers with little decline, but
S. aureus, K. pneumoniae, S. typhimurium, S. cerevisiae
, and vegetative cells of
B. subtilis
failed to survive in samples of sewage and lake water. In sterile sewage, however,
K. pneumoniae, B. subtilis, S. typhimurium, A. tumefaciens
, and
R. meliloti
grew;
S. cerevisiae
populations were maintained at the levels used for inoculation; and
S. aureus
died rapidly. In sterile lake water, the population of
S. aureus
and
K. pneumoniae
and the number of vegetative cells of
B. subtilis
declined rapidly,
R. meliloti
grew, and the other species maintained significant numbers with little or a slow decline. The populations of
S. aureus, K. pneumoniae, A. tumefaciens, B. subtilis
, and
S. typhimurium
declined in soil, but the first four species grew in sterile soil. It is suggested that some species persist in environments in which they are not indigenous because they tolerate abiotic stresses, do not lose viability readily when starved, and coexist with antagonists. The species that fails to survive need only be affected by one of these factors.
Exposure to ozone reduces influenza disease severity and alters distribution of influenza viral antigens in murine lungs
Authors: Wolcott J A , Zee Y C , Osebold J W
Published: January 2020

Exposure to ambient levels of ozone (0.5 ppm) was shown to alter the pathogenesis of respiratory infection after aerosol infection of mice with influenza A virus. A semiquantitative method for determination of the sites of virus replication by direct immunofluorescence indicated that exposure to ozone reduced the involvement of respiratory epithelium in the infectious process and resulted in a less widespread infection of the alveolar parenchyma. Furthermore, the ozone-mediated alteration in viral antigen distribution was consistent with significantly reduced influenza disease mortality and prolonged survival time, but only when the oxidant was present during the course of infection. Reduced disease severity in ozone-exposed animals appeared to be independent of peak pulmonary virus titers, pulmonary interferon titers, and pulmonary and serum-neutralizing antibody titers. These studies suggested that the distribution of influenza virus in the murine lung was a key factor in disease severity.
Aerobic, Selenium-Utilizing Bacillus Isolated from Seeds of
Astragalus crotalariae
Authors: Lindblow-Kull Carole , Shrift Alex , Gherna Robert L.
Published: January 2020

Bacillus
sp. strain SS, an aerobic, gram-positive sporeformer, was isolated from seeds of
Astragalus crotalariae
, a selenium-accumulating plant. This bacillus grew in a nutrient broth (containing beef extract and peptone) if the medium was supplemented with high concentrations of selenium. Concentrations of Na
2
SeO
3
that supported growth ranged from 3 to 100 mM. After 24 h of growth, the culture developed a deep red color characteristic of elemental selenium. When selenium was provided in the form of selenate, the pattern of growth showed a prolonged lag period, from 24 to 48 h. Final growth remained below that of cells cultured in the presence of selenite, and only a light red color developed. Concentrations of selenate below 40 mM failed to support growth. Tellurate, though not tellurite, could replace selenite, but only over a narrow concentration range, 5 to 10 mM. By 24 h, the typical black color of elemental tellurium developed.
Bacillus
sp. strain SS grew also in brain heart infusion broth and Trypticase soy broth (BBL Microbiology Systems, Cockeysville, Md.) without the addition of selenium or tellurium compounds. When added to these media, 50 mM selenite was tolerated and metabolized by the organism. The crucial distinction between this bacillus and other selenium-tolerant organisms (e.g.,
Salmonella
) remains: under certain conditions, growth requirements of
Bacillus
sp. strain SS are fulfilled by selenium (and tellurium) compounds.
Selective Isolation of
Fusarium graminearum
Mutants Derepressed for Production of β-Glucosidase
Authors: Loureiro-Dias Maria C.
Published: January 2020

A strain of
Fusarium graminearum
produced extracellular β-glucosidase (β-
d
-glucoside glucohydrolase [EC 3.2.1.21]) subject to carbon catabolite repression. Derepressed mutants were selectively isolated by the use of 2-deoxyglucose, a nonmetabolizable catabolic repressor. On each plate of cellobiose and 2-deoxy-glucose inoculated with 10
6
spores and irradiated with UV light, a few colonies emerged. Comparative growth experiments with one of the derepressed mutants and the parent strain showed that the mutant produced β-glucosidase in the presence of glucose. Furthermore, the same mutant produced more β-glucosidase than did the wild-type strain on cellobiose alone.
Initial Stages in the Biodegradation of the Surfactant Sodium Dodecyltriethoxy Sulfate by
Pseudomonas
sp. Strain DES1
Authors: Hales Stephen G. , Dodgson Kenneth S. , White Graham F. , Jones Norman , Watson G. Keith
Published: January 2020

The biodegradation of the surfactant sodium dodecyltriethoxy sulfate by
Pseudomonas
sp., strain DES1 (isolated from activated sludge plant effluent) has been studied. Growth of the organism when the
35
S-labeled surfactant was present as the sole source of carbon and energy led to the appearance in the culture fluid of five
35
S-labeled organic metabolites. These have been identified as mono-, di-, and triethylene glycol monosulfates (major metabolites) and acetic acid 2-(ethoxy sulfate) and acetic acid 2-(diethoxy sulfate), authentic samples of which have been prepared and characterized. Evidence is presented that the major metabolites were produced by rupture of one or another of the three ether linkages present in the surfactant molecule, probably via the agency of a single etherase enzyme. Acetic acid 2-(ethoxy sulfate) and acetic acid 2-(diethoxy sulfate) were formed by the oxidation of the free alcohol groups of di- and triethylene glycol monosulfates, respectively, and increased in amount during the stationary phase of growth. Inorganic
35
S-sulfate also appeared in significant quantities in culture fluids and arose from the parent surfactant (presumably via the action of an alkylsulfatase) and not from any of the five metabolites. The appearance of sulfated organic metabolites during the exponential phase of growth and their quantitative relationship remained remarkably constant, even when additional carbon and energy sources (succinate or yeast extract) were also present in the growth media.
Mutagenicity and toxicity of carcinogenic and other hydrazine derivatives: correlation between toxic potency in animals and toxic potency in Salmonella typhimurium TA1538
Authors: Malca-Mor L , Stark A A
Published: January 2020

Eleven hydrazine derivatives and an aromatic amine were examined for mutagenicity and toxicity to Salmonella typhimurium. Phenylhydrazine, 2-nitrophenylhydrazine, 4-nitrophenylhydrazine, 2,4-dinitrophenylhydrazine, p-tolylhydrazine, and 4-nitroaniline were found to be frameshift mutagens (strain TA1538). Benzylhydrazine, m-hydroxybenzylhydrazine, p-hydrazinobenzoic acid, L-tyrosine hydrazide, p-aminobenzoyl hydrazide, and isoniazid were not mutagenic. All chemicals were toxic to strain TA1538. A qualitative correlation was found between the pK of the compounds and their mutagenicity. Relative toxicities of hydrazines to bacteria were found to be closely correlated with the relative toxicities of the same compounds in animals. Described herein is a methodology for the rapid prescreening of chemicals which may be used as drugs for those with a high benefit/risk ratio.
Rapid enumeration of microorganisms in foods by the direct epifluorescent filter technique
Authors: Pettipher G L , Rodrigues U M
Published: January 2020

Filtration of "stomachered" food suspensions through nylon filters (pore size, 5 microns) removed most of the food debris without affecting the recovery of microorganisms. Two to ten milliliters of these prefiltered suspensions could be filtered in the direct epifluorescent filter technique (DEFT). The technique takes less than 30 min to complete and has a lower sensitivity of less than 60,000 microorganisms per g for all products examined. Vegetative bacterial cells, spores, fungal hyphae, and yeasts could be distinguished with the technique. For fresh meat and fish, the DEFT count of prefiltered suspensions agreed well with the plate count of unfiltered suspensions over the range of 10(4) to 10(10)/g (correlation coefficient of 0.91). For frozen meat and fish and frozen vegetables, the two counting methods had correlation coefficients of 0.87 and 0.66, respectively. The poor correlation for frozen vegetables was due to the inclusion in the DEFT count of nonviable bacteria killed by the blanching process used to inactivate enzymes. Good agreement was obtained between the prefiltered DEFT count and unfiltered plate count for cooked meats, cream doughnut, and whole peppers. Possible reasons for the poor agreement between the DEFT count and plate count for certain products are discussed.
In situ studies with membrane diffusion chambers of antibiotic resistance transfer in Escherichia coli
Authors: Altherr M R , Kasweck K L
Published: January 2020

Coliform bacteria were isolated from raw sewage and sewage effluent-receiving waters and tested for their antibiotic susceptibility patterns and their ability to transfer antibiotic resistance to Escherichia coli K-12 C600. An environmental isolate of E. coli (MA527) capable of transferring antibiotic resistance to C600 was mated, both in vitro and in situ, with an antibiotic-sensitive E. coli environmental isolate (MA728). In situ matings were conducted in modified membrane diffusion chambers, in the degritter tank at the Grant Street (Melbourne, Fla.) sewage treatment facility, and in the sewage effluent-receiving waters in Melbourne, Fla. The transfer frequencies in situ were 3.2 x 10(-5) to 1.0 x 10(-6), compared with 1.6 x 10(-4) to 4.4 x 10(-5) observed in vitro. Transfer was shown to occur in raw sewage but was not detected in the effluent-receiving waters. The presence of a 60-megadalton plasmid species in both donor and transconjugants, but not in the recipients, provided physical evidence for the transfer of antibiotic resistance in situ.
Solvent systems for improved isolation and separation of territrems A and B
Authors: Ling K H , Yang C K , Kuo C A , Kuo M D
Published: January 2020

Territrems A and B, tremorgenic mycotoxins in the rice culture of Aspergillus terreus, were extracted with hot chloroform. The toxins were cleaned on a silica gel column by direct adsorption-concentration of the extracts followed by desorption with chloroform-acetone (9:1, vol/vol). Crude toxin mixtures were separated by silica gel column chromatography and eluted with benzene-ethyl acetate (65:35, vol/vol). The method gave 112 mg of territrem A, 379 mg of territrem B, and 80 mg of their mixture from 4 kg of rice per batch. The criteria of extraction, cleanup, and separation are provided.
Concurrent Production and Consumption of Ethanol by Cultures of
Pachysolen tannophilus
Growing on
d
-Xylose
Authors: Maleszka Ryszard , Schneider Henry
Published: January 2020

Growing cultures of
Pachysolen tannophilus
concurrently consumed and produced ethanol in the presence of substantial concentrations of
d
-xylose. Ethanol was also assimilated in the presence of other sugars, the amount depending on the sugar. Less ethanol assimilation occurred with
d
-glucose than with
d
-xylose. The rate of ethanol consumption decreased as the concentration of glucose was increased, but some consumption still occurred when 2% glucose was present. The rate increased with the amount of oxygen available to the culture when
d
-xylose or ethanol was the carbon source. In most instances, estimates of consumption were based on the extent of incorporation of
14
C from [1-
14
C]ethanol into trichloroacetic acid-insoluble material. The results are pertinent to the use of
P. tannophilus
for the production of ethanol from
d
-xylose.
Nitrogen Redox Metabolism of a Heterotrophic, Nitrifying-Denitrifying
Alcaligenes
sp. from Soil
Authors: Castignetti Domenic , Hollocher Thomas C.
Published: January 2020

Metabolic characteristics of a heterotrophic, nitrifier-denitrifier
Alcaligenes
sp. isolated from soil were further characterized. Pyruvic oxime and hydroxylamine were oxidized to nitrite aerobically by nitrification-adapted cells with specific activities (
V
max
) of 0.066 and 0.003 μmol of N × min
−1
× mg of protein
−1
, respectively, at 22°C.
K
m
values were 15 and 42 μM for pyruvic oxime and hydroxylamine, respectively. The greater pyruvic oxime oxidation activity relative to hydroxylamine oxidation activity indicates that pyruvic oxime was a specific substrate and was not oxidized appreciably via its hydrolysis product, hydroxylamine. When grown as a denitrifier on nitrate, the bacterium could not aerobically oxidize pyruvic oxime or hydroxylamine to nitrite. However, hydroxylamine was converted to nearly equimolar amounts of ammonium ion and nitrous oxide, and the nature of this reaction is discussed. Cells grown as heterotrophic nitrifiers on pyruvic oxime contained two enzymes of denitrification, nitrate reductase and nitric oxide reductase. The nitrate reductase was the dissimilatory type, as evidenced by its extreme sensitivity to inhibition by azide and by its ability to be reversibly inhibited by oxygen. Cells grown aerobically on organic carbon sources other than pyruvic oxime contained none of the denitrifying enzymes surveyed but were able to oxidize pyruvic oxime to nitrite and reduce hydroxylamine to ammonium ion.
Chlorine resistance patterns of bacteria from two drinking water distribution systems
Authors: Ridgway H F , Olson B H
Published: January 2020

The relative chlorine sensitivities of bacteria isolated from chlorinated and unchlorinated drinking water distribution systems were compared by two independent methods. One method measured the toxic effect of free chlorine on bacteria, whereas the other measured the effect of combined chlorine. Bacteria from the chlorinated system were more resistant to both the combined and free forms of chlorine than those from the unchlorinated system, suggesting that there may be selection for more chlorine-tolerant microorganisms in chlorinated waters. Bacteria retained on the surfaces of 2.0-microns Nuclepore membrane filters were significantly more resistant to free chlorine compared to the total microbial population recovered on 0.2-micron membrane filters, presumably because aggregated cells or bacteria attached to suspended particulate matter exhibit more resistance than unassociated microorganisms. In accordance with this hypothesis, scanning electron microscopy of suspended particulate matter from the water samples revealed the presence of attached bacteria. The most resistant microorganisms were able to survive a 2-min exposure to 10 mg of free chlorine per liter. These included gram-positive spore-forming bacilli, actinomycetes, and some micrococci. The most sensitive bacteria were readily killed by chlorine concentrations of 1.0 mg liter-1 or less, and included most gram-positive micrococci, Corynebacterium/Arthrobacter, Klebsiella, Pseudomonas/Alcaligenes, Flavobacterium/Moraxella, and Acinetobacter.
Optimization of Conditions for Photoproduction of Ammonia from Nitrate by
Anacystis nidulans
Authors: Ramos Juan L. , Guerrero Miguel G. , Losada Manuel
Published: January 2020

The effect of several relevant environmental factors influencing the photoproduction of ammonia from nitrate by
Anacystis nidulans
cells treated with the glutamine synthetase inhibitor
l
-methionine-
dl
-sulfoximine has been investigated. The optimal ratio between
l
-methionine-
dl
-sulfoximine concentration (micro-molar) and cell density (micrograms of chlorophyll per milliliter) was around 1, the process taking place at maximal rate at a temperature of about 40°C, within the pH range of 7 to 10. Ammonia production was stimulated by CO
2
or bicarbonate and was not affected by the accumulation of ammonia in the medium up to concentrations of 30 mM. The rate of ammonia production was found to be determined by the interaction of at least four factors, namely, irradiance and the density, depth, and turbulence of the cell suspension. Ammonia photoproduction from nitrate and water represents an interesting process for the conversion of light energy into chemical energy, which can operate at high efficiency, around 30% of its theoretical maximum.