bluuebunny/crossref_metadata_2025 huggingface dataset:
Autolytic Activity and an Autolysis-Deficient Mutant of
Clostridium acetobutylicum
Authors: Allcock Errol R. , Reid Sharon J. , Jones David T. , Woods David R.
Published: January 2020

The optimum conditions for autolysis and autoplast formation in
Clostridium acetobutylicum
P262 have been defined. Autolysis was optimal at pH 6.3 in 0.04 M sodium phosphate buffer, and the bacterium produced latent and active forms of an autolytic enzyme. The ability of cells to autolyze decreased sharply when cultures entered the stationary phase. Autoplasts were induced by 0.25 to 0.5 M sucrose and were stable in media containing sucrose, CaCl
2
, and MgCl
2
. A pleiotropic autolysis-deficient mutant (
lyt-1
) was isolated. The mutant produced less autolysin than did the parent P262 strain, and it had an altered cell wall which was more resistant to both its own and P262 autolysins. The mutant formed long chains of cells, and lysozyme was required for the production of autoplasts. Growth of the P262 strain or the
lyt-1
mutant was inhibited by the same concentrations of penicillin, ampicillin, and vancomycin. The
lyt-1
mutant strain treated with the minimum growth-inhibitory concentration of penicillin autolyzed upon the addition of wild-type autolysin to the autolysis buffer at the same rate as did the untreated P262 strain. Chloramphenicol did not protect the penicillin-treated
lyt-1
cells against autolysis enhanced by exogenous wild-type autolysin.
Use of a Fractional Factorial Design to Evaluate Interactions of Environmental Factors Affecting Biodegradation Rates
Authors: Fannin Timothy E. , Marcus Michael D. , Anderson Donald A. , Bergman Harold L.
Published: January 2020

For investigation of main and interactive effects of six experimentally controlled environmental factors on phenol biodegradation in a shake-flask system, a largely neglected statistical procedure was applied. A major benefit resulting from the application of the orthogonal, fractional factorial design is that the number of experiments necessary to evaluate multifactor interactions is limited. In our investigation, the required number of experiments was reduced to 81 from the 324 necessary with conventional factorial designs; information was sacrificed for only 3 of 15 possible two-factor interactions. Six experimentally controlled factors were investigated at two or three treatment levels each; the six factors were (1) amount of phenol substrate, (2) amount of bacterial inoculum, (3) filtration of inoculum, (4) type of basal salts medium, (5) initial pH of basal salts medium, and (6) flask closure. Significant main effects were found for factors 1, 2, and 4; whereas significant interactive effects were found only for factor 2 with factor 3 and for factor 2 with factor 5. Our results suggest that the application of these statistical designs will greatly reduce the number of experiments necessary to evaluate multifactor effects on degradation rates during optimization of both hazard screening systems and waste treatment systems.
Facile Method for Monitoring Inhibition of Anaerobic Spore Outgrowth
Authors: Benedict Robert C. , Tartaglia J. S.
Published: January 2020

A device is presented for the laboratory monitoring of spore outgrowth under controlled temperature and anaerobic conditions. Alterations in pH, redox potential, headspace composition, and optical density are followed as the activated spores grow out into vegetative cells. An interlock system allows the addition of test solutions or the removal of medium under anaerobic conditions. The device may also be used for rapid (<4 h) chemical inhibition studies or adapted for temperature injury studies of aerobic or anaerobic cells. Data on outgrowth of
Clostridium sporogenes
and inhibition by nitrite solutions are presented.
Population of Aerobic Heterotrophic Nitrogen-Fixing Bacteria Associated with Wetland and Dryland Rice
Authors: Barraquio W. L. , de Guzman M. R. , Barrion M. , Watanabe I.
Published: January 2020

Nitrogen-fixing activity and populations of nitrogen-fixing bacteria associated with two varieties of rice grown in dryland and wetland conditions were measured at various growth stages during the dry season. Acetylene reduction activities were measured both in the field and for the hydroponically grown rice, which was transferred from the field to water culture 1 day before assay. The activities measured by both methods were higher in wetland than in dryland rice. The population of nitrogen-fixing heterotrophic bacteria associated with rhizosphere soil, root, and basal shoots was determined by the most probable number method with semisolid glucose-yeast extract and semisolid malate-yeast extract media. The number of nitrogen-fixing bacteria was higher in wetland conditions than in dryland conditions. The difference between two conditions was most pronounced in the population associated with the basal shoot. The glucose medium gave higher counts than did the malate medium. Colonies were picked from tryptic soy agar plates, and their nitrogen-fixing activity was tested on a semisolid glucose-yeast extract medium. The incidence of nitrogen-fixing bacteria among aerobic heterotrophic bacteria in association with rhizosphere soil, root, and basal shoots was much lower in dryland rice than in wetland rice.
Characterization of Bacteria from a Swine Manure Digester
Authors: Iannotti E. L. , Fischer J. R. , Sievers D. M.
Published: January 2020

One-hundred thirty bacteria isolated from a swine manure digester were predominately gram-positive anaerobes which were tentatively classified into the following genera:
Peptostreptococcus, Eubacterium, Bacteroides, Lactobacillus, Peptococcus, Clostridium
, and
Streptococcus
plus two unidentified groups. The major fermentation products formed by these organisms included acetate, propionate, succinate, lactate, and ethanol, singly or in various combinations. Acetate was the sole end product of several groups. Few of the isolates (14%) reduced the pH below 6.0. The predominate bacteria appear to differ from the predominate organisms isolated from other anaerobic ecosystems.
Biodegradation of Glycidol and Glycidyl Nitrate
Authors: Kaplan David L. , Cornell John H. , Kaplan Arthur M.
Published: January 2020

When calcium hydroxide is used to desensitize glycerol trinitrate (nitroglycerine)-containing waste streams, the epoxides glycidol and glycidyl nitrate are formed. The epoxide rings of both compounds are unstable to heat in aqueous solutions, and they open to form glycerol 1-mononitrate and presumably glycerol. These transformations were accelerated by microbial activity. Glycerol 1-mononitrate was slowly denitrated to form glycerol. Glycidol and glycidyl nitrate caused base-pair substitutions in the Ames test for mutagenicity, whereas glycerol 1-mononitrate tests were negative.
Detection and quantitation of Newcastle disease virus proteins in infected chicken embryo cells
Authors: Bolen J B , Garfinkle J A , Consigli R A
Published: January 2020

A technique was analyzed by which Newcastle disease virus (NDV) proteins could be quantitatively detected in the presence of chicken embryo cellular proteins in NDV-infected cells. The technique involved removal of electropho-proteins from a sodium dodecyl sulfate-polyacrylamide-agarose gel matrix by chemical cleavage of the acrylamide gel cross-linker. The proteins were subsequently transferred and covalently bound to diazobenzyloxymethyl paper. By incubating the paper with unlabeled antisera and 125I-labeled Staphylococcus aureus protein A, the specificity of the antisera and the sensitivity of this method of quantitative antigen detection were tested. The results demonstrated that as little as 1 ng of an individual NDV protein could be detected. Furthermore, this technique can simultaneously quantitate the synthesis of multiple NDV proteins under experimental conditions in which immunofluorescence, hemadsorption, and plaque assays failed to show virus protein synthesis or the formation of virus progeny.
Transposon Mutagenesis in Rhizobia Which Can Nodulate Both Legumes and the Nonlegume
Parasponia
Authors: Cen Y. , Bender G. L. , Trinick M. J. , Morrison N. A. , Scott K. F. , Gresshoff P. M. , Shine J. , Rolfe B. G.
Published: January 2020

The successful use of transposon mutagenesis in a slow-growing
Rhizobium
permitted the isolation of auxotrophic and symbiotically defective mutants. In these mutants, it was shown that different single-copy Tn
5
insertions had occurred. Mutant phenotypes indicated that the control of nitrogenase activity in vitro and in planta is different.
Medium for Enhanced Growth of Bacteria from a Swine Manure Digester
Authors: Iannotti E. L. , Fischer J. R. , Sievers D. M.
Published: January 2020

Most bacterial strains isolated from a swine manure digester grew sufficiently to permit transfer of cultures, but not characterization. Substrates, crude extracts, growth factors, and electron acceptors were evaluated for growth promotion. The growth of all but one group of the isolates was substantially increased with a medium containing glucose, cellobiose, soluble starch, pyruvate, peptone, yeast extract, minerals, volatile acids, vitamins, hemin plus vitamins K
1
and K
3
, sodium bicarbonate, cysteine, and digester fluid. The strains require both known and unknown factors (in crude extracts) for maximal growth.
Drug resistance plasmids in Lactobacillus acidophilus and Lactobacillus reuteri
Authors: Vescovo M , Morelli L , Bottazzi V
Published: January 2020

Sixteen strains of Lactobacillus reuteri and 20 strains of Lactobacillus acidophilus were tested for resistance to 22 antibiotics by using commercially available sensitivity disks. Evidence suggesting linkage of these resistances to plasmids was obtained by "curing" experiments with acridine dyes and high growth temperatures. Examination of plasmid patterns of agarose gel electrophoresis provided further evidence of loss in plasmid DNA under curing conditions in some of the strains examined.
Effect of lactic acid concentration on growth on meat of Gram-negative psychrotrophs from a meatworks
Authors: Gill C O , Newton K G
Published: January 2020

The inhibitory effect of the lactic acid in meat on gram-negative psychrotrophs appears to be due mainly to the decrease in pH, not to action of the undissociated acid. Species of Pseudomonas were essentially unaffected by the pH of normal meat. Other gram-negative psychrotrophs isolated from a meatworks included a large number of strains which would not grow on meat of normal pH at chill temperatures. Raising either the pH or the incubation temperature allowed many of the pH-sensitive strains to initiate growth. However, the growth rates of pH-insensitive strains were not affected by increasing the pH, and there were no significant differences in the composition of the spoilage floras which developed on chilled meat of normal and high pH.
Disposition of Mycophenolic Acid, Brevianamide A, Asperphenamate, and Ergosterol in Solid Cultures of
Penicillium brevicompactum
Authors: Bird B. A. , Campbell I. M.
Published: January 2020

When
Penicillium brevicompactum
was grown between layers of dialysis membrane on Czapek-Dox agar for 3 days, no synthesis of mycophenolic acid, brevianamide A, asperphenamate, or ergosterol occurred. After removal of the uppermost membrane layer, aerial mycelium developed and all four metabolites were formed. The bulk of the mycophenolic acid that was formed was excreted into the medium, the bulk of the brevianamide A and asperphenamate was found in the aerial hyphae, and ergosterol was found in both vegetative and aerial mycelia.
Characterization of
Nocardia amarae
as a Potent Biological Coalescing Agent of Water-Oil Emulsions
Authors: Cairns William L. , Cooper David G. , Zajic James E. , Wood Joan M. , Kosaric Naim
Published: January 2020

Nocardia amarae
grown in a liquid medium induced coalescence of emulsions which differed in type, composition of the organic phase, and structure of stabilizing emulsifiers. De-emulsifying activity varied with the type of growth medium, culture age, and postharvest treatment. Based on extraction and degradation studies, it was concluded that de-emulsifying properties are due to the bacterial cell surface. Thus, bacteria may provide a new source of de-emulsifying agents.
Transformation of Adenine to 8-Hydroxyadenine by Strains of
Oerskovia xanthineolytica
Authors: Lechevalier Mary P. , Gerber Nancy N. , Umbreit Thomas A.
Published: January 2020

The 8-hydroxy derivative of adenine (6-amino-1,7-dihydro-8
H
-purin-8-one) is produced from adenine by two
Oerskovia xanthineolytica
strains. This transformation by a microorganism has not been reported previously. No novel products of dissimilation of xanthine (3,7-dihydro-1
H
-purine-2,6-dione) or hypoxanthine (1,7-dihydro-6
H
-purin-6-one) were found. Xanthine was oxidized to uric acid, but intermediates in the breakdown of hypoxanthine could not be demonstrated.
Seasonal Variability and Transport of Suspended Microfungi in a Southeastern Salt Marsh
Authors: Chrzanowski Thomas H. , Stevenson L. Harold , Spurrier J. D.
Published: January 2020

Tidally induced fluctuations and transports of microfungi were investigated. Samples were collected at three depths from three stations positioned at a transect in a large salt marsh creek. Samples were taken every 1.5 h for 50 consecutive h during neap tides and 50 consecutive h during the corresponding spring tides. In each season, microfungi concentrations fluctuated out of phase with the tides during both neap and spring tides. Mean concentrations of suspended microfungi did not vary appreciably throughout the year. Fungi were exported from the marsh during the majority of the tidal cycles studied. The results suggest that microfungi may serve as indicators of water mass movements.
The Microaerophile
SPirillum volutans
: Cultivation on Complex Liquid and Solid Media
Authors: Padgett Penelope J. , Cover William H. , Krieg Noel R.
Published: January 2020

Spirillum volutans
grows only under microaerobic conditions in a peptone-succinate-salts broth, but can grow aerobically when the peptone is replaced by vitamin-free acid-hydrolyzed casein broth. The addition of potassium metabisulfite, norepinephrine, catalase or superoxide dismutase (SOD) permitted aerobic growth in peptone-succinate-salts broth. A combination of catalase and SOD had a synergistic effect.
S. volutans
lacked catalase and had only a low level of peroxidase activity, but did possess SOD activity (12 to 14 U/mg of protein). The organism was found to be extraordinarily sensitive to exogenous hydrogen peroxide. Illumination of peptone-succinate-salts broth generated hydrogen peroxide and rendered the medium inhibitory to growth. A combination of catalase and SOD prevented this inhibition. Growth of
S. volutans
on solid media, not previously possible, was accomplished by the use of vitamin-free acid-hydrolyzed casein and peptone-succinate-salts agar media; maximum growth responses were dependent on the following combination of factors: addition of bisulfite, catalase, or SOD, protection of the media from illumination, incubation in a highly humid atmosphere, and incubation under atmospheres of 12% oxygen or less. The results indicate that the microaerophilic nature of
S. volutans
is attributable largely to the high sensitivity of the organism to exogenous hydrogen peroxide and, to a lesser extent, superoxide radicals occurring in the culture medium.
Simplified Microassay for Pullulan Synthesis
Authors: Finkelman M. A. J. , Vardanis A.
Published: January 2020

A simple radiometric microassay for extracellular polysaccharide elaboration by yeast-like cells of
Aureobasidium pullulans
was developed, based upon a procedure originally described by Catley (FEBS Lett.
20
:174-176, 1972). Incorporation of [
14
C]glucose into pullulan was linear with respect to time and cell dose. The pH and temperature optima for elaboration were 5.3 and 30°C, respectively. Polysaccharide elaboration declined linearly with culture age.
Inexpensive treatment of frozen dairy products for membrane filtration
Authors: Peterkin P I , Sharpe A N , Warburton D W
Published: January 2020

Treatment of frozen dairy products with trypsin and Tween 80 before membrane filtration for microbiological analysis was faster and cost less than treatment with Streptomyces griseus protease-Tween 80. Viable cell counts so Escherichia coli, Staphylococcus aureus, Streptococcus faecium, and Salmonella typhimurium were not reduced.
Influence of Stabilizer Concentration on Effectiveness of Chlorine as an Algicide
Authors: Sommerfeld Milton R. , Adamson Richard P.
Published: January 2020

Cyanuric acid, used as chlorine stabilizer in swimming pool waters, has a relatively minor effect on the algicidal efficiency of free chlorine. The toxicity of free chlorine to three swimming pool algae was reduced slightly by 25 mg of cyanuric acid per liter if inhibiting, but less than algicidal, concentrations of chlorine were employed. Higher stabilizer concentrations (50, 100, and 200 mg/liter) generally resulted in no further reduction in the algicidal efficiency of free chlorine beyond that observed at 25 mg/liter.
Metabolism of verruculogen in rats
Authors: Perera K P , Day J B , Mantle P G , Rodrigues L
Published: January 2020

Radiolabeled verruculogen was detected in a wide range of body tissues 6 min after intravenous administration, but after a further 20 min it was mainly being excreted via the biliary route. In isolated liver perfusion, [14C]verruculogen was rapidly taken up by the liver and metabolized completely, principally to the related tremorgen TR-2 but also to a desoxy derivative of verruculogen. In addition, a smaller amount of an isomer of TR-2 was detected. These metabolic products were excreted in the bile.
Ozone decontamination of bioclean rooms
Authors: Masaoka T , Kubota Y , Namiuchi S , Takubo T , Ueda T , Shibata H , Nakamura H , Yoshitake J , Yamayoshi T , Doi H , Kamiki T
Published: January 2020

To establish a convenient method for decontaminating bioclean rooms, the effect of ozone at 80 mg/m3 for 72 h was compared with formaldehyde vaporization at an initial concentration of 150 mg/m3 with a gradual decrease to 20 mg/m3 during 72 h. Ozone was found to be inferior to formaldehyde in activity. When the bioclean room was decontaminated twice with ozone, the mean colony count per 10 cm2 was decreased to about the same level as when formaldehyde was used. Ozone had a strong caustic effect upon rubber materials. Despite these disadvantages, ozone decontamination was demonstrated to be superior to formaldehyde vaporization because of convenience, insignificant inhalation of the disinfectant by the hospital staff, and very rapid expulsion of the gas after ventilation. Because the disadvantages of ozone can be easily controlled, this study suggests that ozone decontamination is a promising method for maintaining bioclean rooms.
Role of versicolorin A and its derivatives in aflatoxin biosynthesis
Authors: Dutton M F , Anderson M S
Published: January 2020

The involvement of various anthraquinone metabolites in the biosynthesis of aflatoxin B1 was investigated by using a labeled double-substrate technique in a cell-free system. The results showed that both versicolorin A hemiacetal and versicolorin A hemiacetal acetate were converted to aflatoxin B1, whereas versicolorin A was not, even though it was added to the same cell-free system. Thus, versicolorin A hemiacetal, versicolorin A hemiacetal acetate, or both were implicated as key intermediates, whereas versicolorin A and C became side shunt metabolites. These latter compounds reentered the pathway depending on the availability of the appropriate enzymes and suitability of conditions. Dichlorvos, a specific inhibitor of aflatoxin biosynthesis, is considered to have its primary action on either an oxygenase or dehydrogenase involved in the pathway and to act in a secondary capacity as an inhibitor of an esterase which may also be involved in the pathway.
Aminopeptidase Profiles of Four Species of
Phytophthora
Authors: Huber D. M. , Fortes J. F. , Pecknold P. C. , Harmon M. C.
Published: January 2020

Phytophthora palmivora, P. cinnamomi, P. drechsleri
, and
P. cactorum
were readily separated on the basis of the aminopeptidase substrate specificities of their mycelial suspensions. Variability among isolates of the same species was not significant with most substrates and isolates tested, regardless of source. Both qualitative and quantitative differences in enzyme activity were useful for species identification. Differentiation of these four species was possible with comparative reactions of
l
-alanyl-,
l
-arginyl-,
l
-benzoylarginyl,
l
-gamma-glutamyl-,
l
-glycyl-,
l
-hydroxyprolyl-,
l
-leucyl-,
l
-lysyl-, 4-methoxyleucyl-,
l
-prolyl-, and 4-methoxyalanyl-beta-naphthylamides. Variation in peptidase activity was usually detectable after 4 h of incubation, with increased activity sometimes manifest after 24 h of incubation.
P. palmivora
exhibited the lowest, and
P. drechsleri
exhibited the highest, overall peptidase activity. This fluorescent aminopeptidase profile procedure provides a relatively rapid method to supplement other taxonomic criteria for identification of these species of
Phytophthora.
Single-Cell Protein Production by the Acid-Tolerant Fungus
Scytalidium acidophilum
from Acid Hydrolysates of Waste Paper
Authors: Ivarson K. C. , Morita H.
Published: January 2020

The bioconversion of waste paper to single-cell protein at pH <1 by
Scytalidium acidophilum
is described. Waste paper pretreated with 72% H
2
SO
4
at 4°C was diluted with water to a pH of <0.1 and hydrolyzed. This yielded an adequate sugar-containing substrate for the growth of the fungus. A total of 97% of the sugars (glucose, galactose, mannose, xylose, arabinose) in the hydrolysates were converted to cell biomass. Microbial contamination was not observed. Based on the sugars consumed,
S. acidophilum
produced higher yields in shake cultures than many other
Fungi Imperfecti.
In aerated cultures, productivity increased, and yields of 43 to 46% containing 44 to 47% crude protein were obtained. This compares favorably with
Candida utilis
, a yeast used commercially to produce single-cell protein. The chemical constituents and the essential amino acids of the fungal cells were similar to those of other fungi. The nucleic acid content was characteristic of microbes containing low levels of nucleic acid. The advantages of using
S. acidophilum
for single-cell protein production are discussed.
Denitrification, Nitrate Reduction, and Oxygen Consumption in Coastal and Estuarine Sediments
Authors: Nishio Takashi , Koike Isao , Hattori Akihiko
Published: January 2020

Denitrification and consumption of oxygen and nitrate in sediments from Tama Estuary, Odawa Bay, and Tokyo Bay were measured in an experimental sediment-water system. Filtered seawater containing [
15
N]nitrate flowed continuously over undisturbed sediments, and the concentrations of O
2
, nitrate, and nitrite in the influent and effluent and of
15
N
2
in the effluent were monitored. Under steady-state conditions, the rate of nitrate consumption was the same order of magnitude as the rate of oxygen consumption in Tama Estuary sediments, whereas the former rate was one order of magnitude lower than the latter rate in Odawa Bay and Tokyo Bay sediments. Denitrification accounted for 27 to 57% of the nitrate consumption.
Chemical factors influencing adsorption of bacteriophage MS2 to membrane filters
Authors: Farrah S R
Published: January 2020

Antichaotropic salts, such as magnesium sulfate, and metal chelators, such as citrate ions, promoted adsorption of bacteriophage MS2 to membrane filters. In contrast, compounds that disrupt hydrophobic interactions, such as chaotropic salts, urea, Tween 80, and ethanol, did not promote adsorption of MS2 to membrane filters and counteracted the ability of magnesium sulfate to promote such adsorption. These results provide evidence that magnesium sulfate promotes the association of MS2 with membrane filters primarily by strengthening hydrophobic interactions between the virus and the filters.
Impact of Mount St. Helens Eruption on Bacteriology of Lakes in the Blast Zone
Authors: Staley J. T. , Lehmicke L. G. , Palmer F. E. , Peet R. W. , Wissmar R. C.
Published: January 2020

Lakes lying within the blast zone of Mount St. Helens showed dramatic increases in heterotrophic bacterial numbers after the eruption of 18 May 1980. The total microscopic counts of bacteria in some of the most severely affected lakes were more than 10
7
cells per ml, an order of magnitude above the counts in outlying control lakes. Likewise, the numbers of viable bacteria reached levels of more than 10
6
cells per ml, compated with fewer than 10
4
cells per ml in control lakes. The CPS medium used for enumeration provided growth of up to 81.5% of the bacteria during sampling of one of the blast zone lakes. The high numbers of bacteria and the efficacy of the viable enumeration procedure are evidence that the lakes have been transformed rapidly from oligotrophy to eutrophy due to the eruption and its aftermath. Organic material leached from the devastated forest vegetation is thought to be responsible for the enrichment of heterotrophs. Total coliform bacteria were found in all of the blast zone lakes, and some lakes contained fecal coliform bacteria.
Klebsiella pneumoniae
was the predominant total coliform and was also identified as one of the fecal coliform bacteria, although
Escherichia coli
was the predominant species in that category. Our data indicate that bacterial populations peaked in the outer blast zone lakes in the summer of 1980 and in most of the inner lakes during the summer of 1981.
Physiological diversity of rumen spirochetes
Authors: Paster B J , Canale-Parola E
Published: January 2020

Bovine rumen fluid contained relatively large numbers of spirochetes capable of fermenting polymers commonly present in plant materials. Polymers such as xylan, pectin, and arabinogalactan served as fermentable substrates for the spirochetes, whereas cellulose did not. Furthermore, spirochetes cultured from rumen fluid utilized as growth substrates hydrolysis products of plant polymers (e.g., D-xylose, L-arabinose, D-galacturonic acid, D-glucuronic acid, cellobiose), but did not ferment amino acids. Viable cell counts of spirochetes capable of fermenting individual plant polymers or their hydrolysis products yielded minimum values ranging from 0.2 X 10(6) to 4 X 10(6) cells per ml of rumen fluid. Thirteen strains of rumen spirochetes were characterized in terms of their fermentation products from glucose, the guanine plus cytosine content of their DNA, their ultrastructure, and their ability to ferment pectin, starch, or arabinogalactan. Of the 13 strains, 6 fermented glucose mainly to formate, acetate, and succinate, whereas the remaining 7 strains did not produce succinate, but instead formed ethanol, in addition to formate and acetate. The succinate-forming strains had two periplasmic (axial) fibrils per cell, measured 0.2 to 0.3 by 5 to 8 micrograms, had a guanine plus cytosine content of the DNA ranging from 36 to 38 mol%, and lacked the ability to ferment pectin, starch, or arabinogalactan. The ethanol-forming strains had from 8 to more than 32 periplasmic fibrils per cell, tended to be larger in cell size than the succinate-forming strains, and had a guanine plus cytosine content of the DNA ranging from 41 to 54 mol%. Some of the ethanol-forming strains fermented pectin, starch, or arabinogalactan. The results of this study indicate that the bovine rumen is inhabited by a physiologically and morphologically diverse population of spirochetes. It is likely that these spirochetes contribute significantly to the degradation of plant materials ingested by the ruminants.
Microbial Dynamics of an Epilithic Mat Community in a High Alpine Stream
Authors: Haack Thomas K. , McFeters Gordon A.
Published: January 2020

Studies were conducted to examine interrelationships between the heterotrophic and phototrophic populations within an epilithic community in the outlet stream of a high alpine lake. Levels of nitrates, phosphates, and total organic compounds in the lake were consistently near the lower limits of detectability. Microscopic examination of the community by phase-contrast light microscopy and scanning electron microscopy revealed diatoms, filamentous algae, and bacteria embedded within a dense gelatinous matrix. Chlorophyll
a
and primary productivity measurements had peak values in early August, with subsequent declines. Bacterial heterotrophic activity, as measured by
V
max
, turnover rate, and relative activity, increased significantly as the phototrophic community declined. This trend in heterotrophic activity was not accompanied by an increase in total bacterial numbers as determined by epi-illuminated fluorescence microscopy. These results suggest that the phototrophic community responded to changes in, or interactions among, various chemical and physical factors throughout the study period. The catabolic activity of the sessile bacteria appeared to be positively influenced by changes in the mat environment resulting from the decline of the phototrophic populations.
Geosmin and 2-Methylisoborneol from Cyanobacteria in Three Water Supply Systems
Authors: Izaguirre George , Hwang Cordelia J. , Krasner Stuart W. , McGuire Michael J.
Published: January 2020

Three
Oscillatoria
strains and one
Anabaena
species were isolated from three different water supply systems in California that experienced earthy-musty taste and odor problems in their drinking water. Unialgal cultures, free of actinomycetes, were purged using the Grob closed-loop stripping analysis method, and the resulting methylene chloride extracts were analyzed on a gas chromatograph/mass spectrometer. Geosmin was produced by
Oscillatoria simplicissima
and
Anabaena scheremetievi
, and 2-methylisoborneol was produced by
O. curviceps
and
O. tenuis.
These compounds are the two major causes of earthy-musty tastes and odors in water. In three instances, the major odorant found in culture was previously identified in the water or sediment sample from which the respective organism was isolated.
O. curviceps
was implicated in a taste and odor episode involving 2-methylisoborneol in a major reservoir. Geosmin and 2-methylisoborneol were easily detected with culture samples of only 4 to 25 ml.
Effect of Several Algicides and Surfactants on the Filamentous Bacterium
Leucothrix mucor
Oersted
Authors: McKee Christine , Lightner Donald V.
Published: January 2020

Leucothrix mucor
Oersted, the primary cause of filamentous gill disease in cultured shrimp, was treated with algicides and surfactants by a serial dilution method. It was found to be highly sensitive to those algicides containing quaternary ammonium compounds. Copper-containing compounds and Formalin were less effective, whereas potassium permanganate and two surfactants, Dreft and Alconox, were ineffective.
Comparison of four membrane filter methods for fecal coliform enumeration
Authors: Pagel J E , Qureshi A A , Young D M , Vlassoff L T
Published: January 2020

Four membrane filter methods fecal coliform enumeration were evaluated and compared in six laboratories based on determination of accuracy, specificity, upper counting limit, and recovery comparability. Recovery accuracy with pure cultures ranged from 89 to 100% for m-FC, mTEC (a procedure developed for thermotolerant Escherichia coli), and m-FC2 methods (the latter incorporating a 2-h, 35 degrees C resuscitation period), but was less than 60% for the MacConkey membrane broth method. These figures dropped by approximately 40 to 55% when the cultures were subjected to temperature (10 degrees C) stress. Close to 800 colonies were verified to determine specificity. False-positive colonies occurred most frequently with the m-FC2 method (18%), whereas false-negative colonies were most common on MacConkey membrane broth (26%). In counting range experiments using a variety of samples, the highest upper counting limit was 130 colonies per filter with the mTEC procedure. Recovery comparisons were based on over 130 samples including raw surface waters, raw sewage, and chlorinated and unchlorinated sewage effluents. In general, recoveries were significantly higher with the m-FC2 and mTEC methods; however, on m-FC2, growth of nontarget background organisms was also higher in most cases. Highest recoveries from chlorinated sewage effluents were obtained by the mTEC method, and the addition of a similar resuscitation period to the m-FC procedure (m-FC2) improved fecal coliform recovery from such samples. The best overall performance for fecal coliform enumeration was obtained with the mTEC method with high recovery and low levels of background colonies, good specificity and accuracy, and a high upper counting limit. This procedure also offers the advantage of enumerating E. coli within 24 h.
Kinetics of substrate utilization in adenine-limited chemostat cultures of Bacillus subtilis KYA741
Authors: Tsuchiya K , Kimura T
Published: January 2020

The specific rates of limiting substrate utilization were investigated in adenine- or glucose-limited chemostat cultures of Bacillus subtilis KYA741, an adenine-requiring strain, at 37 degrees C. With the glucose-limited cultures, the specific rate of glucose consumption versus dilution rate gave a linear relationship from which the true growth yield and maintenance coefficient were determined to be 0.09 mg of bacteria per mg of glucose and 0.2 mg of glucose per mg of bacteria per h, respectively. With the adenine-limited cultures, adenine as the limiting substrate was not completely consumed at lower dilution rates (e.g., D less than 0.1), unlike in the glucose-limited cultures. When a linear relationship of specific rate of adenine consumption versus dilution rate was extrapolated to zero dilution rate, a negative value for the specific rate of adenine consumption, -0.01 mg of adenine per mg of bacteria per h, was obtained, giving a true growth yield for adenine of 5.2 mg of bacteria per mg of adenine. On the other hand, the maintenance coefficient of oxygen uptake gave a positive value of 8.1 x 10(-3) mmol/mg of bacteria per h. Based on previous results showing that adenine is resupplied by lysing cells, we developed kinetic models of adenine utilization and cell growth that gave a good estimation of the peculiar behavior of cell growth and adenine utilization in adenine-limited chemostat cultures.
Production of Plant Growth-Regulating Substances by the Vesicular-Arbuscular Mycorrhizal Fungus
Glomus mosseae
Authors: Barea José M. , Azcón-Aguilar Concepción
Published: January 2020

Glomus mosseae
, a representative species of
Endogonaceae (Phycomycetes)
able to form vesicular-arbuscular mycorrhiza, was investigated for phytohormone production. Spores of
G. mosseae
were axenically germinated in water, and the resultant mycelial growth was assayed by standard procedures for extracting plant hormones from microbial cultures. Paper partition chromatography and specific bioassays were used to separate and identify plant growth-regulating substances. The microorganism synthesized at least two gibberellin-like substances, one with
R

f

corresponding in position to authentic gibberellic acid, and four substances with the properties of cytokinins.
Dye-coupled electrode system for the rapid determination of cell populations in polluted water
Authors: Nishikawa S , Sakai S , Karube I , Matsunaga T , Suzuki S
Published: January 2020

We determined cell populations in polluted waters by using a fuel cell-type electrode. The electrode was constructed from a platinum anode, a silver peroxide cathode, and a membrane filter for retaining microorganisms. The principle of cell number determination is based on sensing a redox dye reduced by the microorganisms with the electrode. Sample solutions containing microorganisms were membrane filtered, and the resulting filter containing microbial cells was attached to the surface of a platinum anode. The electrode was immersed in phosphate buffer solution (0.05 M, pH 7) containing a redox dye (2,4-dichlorophenol-indophenol), and the current generated was measured. The response time of the electrode system was 10 to 20 min, and the current generated was proportional to cell populations above 10(4) cells/ml.
Iron Oxidation and Precipitation of Ferric Hydroxysulfates by Resting
Thiobacillus ferrooxidans
Cells
Authors: Lazaroff Norman , Sigal Warren , Wasserman Andrew
Published: January 2020

The oxidation of ferrous ions, in acid solution, by resting suspensions of
Thiobacillus ferrooxidans
produced sediments consisting of crystalline jarosites, amorphous ferric hydroxysulfates, or both. These products differed conspicuously in chemical composition and infrared spectra from precipitates formed by abiotic oxidation under similar conditions. The amorphous sediments, produced by bacterial oxidation, exhibited a distinctive fibroporous microstructure when examined by scanning electron microscopy. Infrared spectra indicated outer-sphere coordination of Fe(III) by sulfate ions, as well as inner-sphere coordination by water molecules and bridging hydroxo groups. In the presence of excess sulfate and appropriate monovalent cations, jarosites, instead of amorphous ferric hydroxysulfates, precipitated from bacterially oxidized iron solutions. It is proposed that the jarositic precipitates result from the conversion of outer-sphere (T
d
) sulfate, present in a soluble polymeric Fe(III) complex, to inner-sphere (C

3
v

) bridging sulfate. The amorphous precipitates result from the further polymerization of hydroxo-linked iron octahedra and charge stabilized aggregation of the resulting iron complexes in solution. This view was supported by observations that bacterially oxidized iron solutions gave rise to either amorphous or jarositic sediments in response to ionic environments imposed after oxidation had been completed and the bacteria had been removed by filtration.
Effect of growth conditions on heat resistance of Arizona bacteria grown in a chemostat
Authors: Ng H
Published: January 2020

The effects of various growth conditions on the heat resistance of Arizona bacteria grown in a continuous-culture device (chemostat) were studied. Using either glucose, NH4Cl, NaH2PO4, or MgCl2 as the rate-limiting nutrient, it was found that the heat resistance, in all cases depended on the dilution rate and, hence, growth rate of the culture. Cells grown at high dilution rates were less heat resistant than those grown at low dilution rates. If, however, the dilution rate was maintained at a constant rate, the higher the growth temperature, the more heat resistant were the cells. Also at any given dilution rate, the cells were most heat resistant when grown at a near neutral pH. Most survival curves were biphasic in shape, indicating the presence in the population of two fractions of cells, one fraction being more resistant than the other. The size of the more heat-resistant fraction varied from almost 100% in very slow-growing cultures to practically 0% in cultures grown at a dilution rate of 0.67 h-1.
Effect of free-radical scavengers on enumeration of thermally stressed cells of Staphylococcus aureus MF-31
Authors: Bucker E R , Martin S E
Published: January 2020

Exposure of crude cell lysates of Staphylococcus aureus MF-31 to 5 or 10 mM hydrogen peroxide resulted in a linear decrease in superoxide dismutase activity. Approximately 13% of the superoxide dismutase activity was lost after 16 min. Thermally stressed and nonstressed cells were exposed to a photochemically generated exogenous flux of superoxide radicals (O2.-). The death of thermally stressed cells was linear with time. Addition of superoxide dismutase or catalase to the O2.- generating system resulted in protection of thermally stressed and nonstressed cells, with the protective effect being greater for thermally stressed cells. Incorporation of O2-, hydroxyl radical, or singlet oxygen scavengers or antioxidants to tryptic soy agar containing 7.5% NaCl did not increase the enumeration of thermally stressed cells.
Cellular Location and Some Properties of Proteolytic Enzymes of Rumen Bacteria
Authors: Kopecny Jan , Wallace R. John
Published: January 2020

Several physical and chemical techniques were used to extract, and to identify the location of, proteolytic enzymes associated with mixed rumen bacteria. Most activity was removable by gentle physical methods such as shaking and brief blending, without cell disruption, indicating that it was associated with coat and capsular material. Proteases were present also in the cell envelope, corresponding to the inner membrane fraction of gram-negative bacteria, and intracellularly and were removable by detergent and French press treatment. Temperature and pH profiles were obtained for the coat enzymes, likely to be the most important in the digestion of food protein. Inhibition studies indicated that these proteases, and those of the whole bacterial fraction from rumen fluid, were predominantly of the cysteine protease type.
Inactivation by gamma irradiation of animal viruses in simulated laboratory effluent
Authors: Thomas F C , Ouwerkerk T , McKercher P
Published: January 2020

Several animal viruses were treated with gamma radiation from a 60Co source under conditions which might be found in effluent from an animal disease laboratory. Swine vesicular disease virus, vesicular stomatitis virus, and blue-tongue virus were irradiated in tissues from experimentally infected animals. Pseudorabies virus, fowl plague virus, swine vesicular disease virus, and vesicular stomatitis virus were irradiated in liquid animal feces. All were tested in animals and in vitro. The D10 values, that is, the doses required to reduce infectivity by 1 log10, were not apparently different from those expected from predictions based on other data and theoretical considerations. The existence of the viruses in pieces of tissue or in liquid feces made no difference in the efficacy of the gamma radiation for inactivating them. Under the "worst case" conditions (most protective for virus) simulated in this study, no infectious agents would survive 4.0 Mrads.
Hot water systems as sources of Legionella pneumophila in hospital and nonhospital plumbing fixtures
Authors: Wadowsky R M , Yee R B , Mezmar L , Wing E J , Dowling J N
Published: January 2020

Samples obtained from plumbing systems of hospitals, nonhospital institutions and homes were cultured for Legionella spp. by plating the samples directly on a selective medium. Swab samples were taken from the inner surfaces of faucet assemblies (aerators, spouts, and valve seats), showerheads, and shower pipes. Water and sediment were collected from the bottom of hot-water tanks. Legionella pneumophila serogroups 1, 5, and 6 were recovered from plumbing fixtures of the hospitals and nonhospital institutions and one of five homes. The legionellae (7 to 13,850 colony-forming units per ml) were also present in water and sediment from hot-water tanks maintained at 30 to 54 degrees C, but not in those maintained at 71 and 77 degrees C. Legionella micdadei was isolated from one tank. Thus legionellae are present in hot-water tanks which are maintained at warm temperatures or whose design results in warm temperatures at the bottom of the tanks. We hypothesize that hot-water tanks are a breeding site and a major source of L. pneumophila for the contamination of plumbing systems. The existence of these bacteria in the plumbing systems and tanks was not necessarily associated with disease. The extent of the hazard of this contamination needs to be delineated.
Saccharification of Complex Cellulosic Substrates by the Cellulase System from
Clostridium thermocellum
Authors: Johnson Eric A. , Sakajoh Mitsuji , Halliwell Geoffrey , Madia Ashwin , Demain Arnold L.
Published: January 2020

True cellulase activity has been demonstrated in cell-free preparations from the thermophilic anaerobe
Clostridium thermocellum
. Such activity depends upon the presence of Ca
2+
and a thiol-reducing agent of which dithiothreitol is the most promising. Under these conditions, native (cotton) and derived forms of cellulose (Avicel and filter paper) were all extensively solubilized at rates comparable with cellulase from
Trichoderma reesei
. Maximum activity of the
Clostridium
cellulase was displayed at 70°C and at pH 5.7 and 6.1 on Avicel and carboxymethylcellulose, respectively. In the absence of substrate at temperatures up to 70°C, carboxymethylcellulase was much more unstable than the Avicel-hydrolyzing activity.
Kinetics and Extent of Mineralization of Organic Chemicals at Trace Levels in Freshwater and Sewage
Authors: Subba-Rao R. V. , Rubin Howard E. , Alexander Martin
Published: January 2020

A sensitive and rapid method was developed to measure the mineralization of
14
C-labeled organic compounds at picogram-per-milliliter or lower levels in samples of natural waters and sewage. Mineralization was considered to be equivalent to the loss of radioactivity from solutions. From 93 to 98% of benzoate, benzylamine, aniline, phenol, and 2,4-dichlorophenoxyacetate at one or more concentrations below 300 ng/ml was mineralized in samples of lake waters and sewage, indicating little or no incorporation of carbon into microbial cells. Assimilation of
14
C by the cells mineralizing benzylamine in lake water was not detected. Mineralization in lake waters was linear with time for aniline at 5.7 pg to 500 ng/ml, benzylamine at 310 ng/ml, phenol at 102 fg to 10 mg/ml, 2,4-dichlorophenoxyacetate at 1.5 pg/ml, and di-(2-ethylhexyl) phthalate at 21 pg to 200 ng/ml, but it was exponential at several
p
-nitrophenol concentrations. The rate of mineralization of 50 and 500 ng of aniline per ml and 200 pg and 2.0 ng of the phthalate per ml increased with time in lake waters. The phthalate and 2,4-dichlorophenoxyacetate were mineralized in samples from a eutrophic but not an oligotrophic lake. Addition to eutrophic lake water of a benzoate-utilizing bacterium did not increase the rate of benzoate mineralization at 34 and 350 pg/ml but did so at 5 and 50 ng/ml. Glucose and phenol reduced the percentage of
p
-nitrophenol mineralized at
p
-nitrophenol concentrations of 200 ng/ml but not at 22.6 pg/ml and inhibited the rates of mineralization at both concentrations. These results show that the kinetics of mineralization, the capacity of the aquatic community to assimilate carbon from the substrate or the extent of assimilation, and the sensitivity of the mineralizing populations to organic compounds are different at trace levels than at higher concentrations of organic compounds.
Variation in Numbers and Mass of Ciliate Protozoa in the Rumens of Sheep Fed Chaffed Alfalfa (
Medicago sativa
)
Authors: Clarke Richard T. J. , Ulyatt Marcus J. , John Andrew
Published: January 2020

Masses and numbers of rumen ciliate protozoa were markedly different in individual sheep fed chaffed alfalfa hay under different feeding regimens. Studies on the ciliate contribution to specific aspects of rumen fermentation should take into account the size of members of each genus in individual animals as well as the numbers present.
Occurrence of aflatoxins in oilseeds providing cocoa-butter substitutes
Authors: Kershaw S J
Published: January 2020

Four oilseeds providing cocoa-butter substitutes--shea, pentadecima, illipe, and salseed--when tested as substrates for aflatoxin production by two strains of Aspergillus parasiticus, gave varying levels of aflatoxin. Aflatoxins were found at low levels occurring naturally in moldy shea-nuts, but none of 21 commercial shea-nut samples contained greater than 20 micrograms of aflatoxin B1 per kg.
Campylobacter jejuni: incidence in processed broilers and biotype distribution in human and broiler isolates
Authors: Shanker S , Rosenfield J A , Davey G R , Sorrell T C
Published: January 2020

Campylobacter jejuni was isolated from 18 of 40 processed broiler carcasses and 134 of 327 cloacal swabs obtained at four processing plants in Sydney, Australia. Three of four flocks examined carried C. jejuni. Eighty-two percent of chicken and 98% of human isolates from the area were of identical biotypes.