bluuebunny/crossref_metadata_2025 huggingface dataset:
Fungal growth on C1 compounds: quantitative aspects of growth of a methanol-utilizing strain of Trichoderma lignorum in batch culture
Authors: Tye R , Willetts A
Published: January 2020

A study was made of some salient parameters that influence growth of the methanol-utilizing fungus Trichoderma lignorum growing in batch culture on a minimal medium containing methanol as the sole source of carbon. Maximum cell yield was recorded at the expense of 1.58 g of methanol per liter. Inhibition was observed with methanol concentrations in excess of 4.7 g/liter. The optimum temperature for fungal growth was 23 degrees C. Growth of the fungus was directly proportional to an inorganic nitrogen concentration up to 0.2 g of NH4NO3 per liter. No inhibition of growth occurred at any concentration of NH4NO3 up to 11 g/liter. The pH of the growth medium decreased from 7.0 to 3.5 during growth of the fungus on methanol, which may have been due, in part, to the accumulation of trace amounts of organic acids in the growth medium. An analysis of the commercial potential of the fungus, as a source of edible protein, indicated that the strain of methanol-utilizing T. lignorum used was uneconomical in terms of the yield and the specific growth rate.
Resistance of Rhizobium strains to phygon, spergon, and thiram
Authors: Odeyemi O , Alexander M
Published: January 2020

Strains of Rhizobium meliloti, Rhizobium sp. nodulating cowpeas, and R. phaseoli derived from cultures susceptible to tetramethylthiuram disulfide (thiram), 2,3-dichloro-1,4-naphthoquinone (phygon), and 2,3,5,6-tetrachloro-p-benzoquinone (spergon), respectively, grew in the presence of high concentrations of the fungicides and converted them to products not toxic to the sensitive rhizobia. The results of chemical assays demonstrated that the pesticides were destroyed by the resistant bacteria but not by the susceptible parent rhizobia. Resting cells of thiram-metabolizing R. meliloti formed large quantities of dimethyldithiocarbamate, dimethylamine, and CS2 from the pesticide. The products were characterized by gas and thin-layer chromatography, colorimetric reactions, and ultraviolet spectrometry. Dimethylamine and CS2 were formed spontaneously from dimethyldithiocarbamate, but the yield was higher in the presence of R. meliloti. The phygon-resistant bacterium converted the fungicide to five metabolites and thereby rendered the chemical nontoxic to a test fungus. The resistant strain of R. phaseoli generated at least one organic product and released about one-third of the chlorine during its detoxication of spergon.
Diurnal changes in concentration of rumen ciliates and in occurrence of dividing forms in water buffalo (Bubalus bubalus) fed once daily
Authors: Michalowski T
Published: January 2020

When buffalo were fed once daily, significant diurnal variations in concentration of rumen ciliates and occurrence of dividing protozoa were found. Differences in proportions of dividing Entodinium- and Diplodinium-type ciliates were also observed. Results obtained suggest that the range of diurnal fluctuations in rumen protozoa concentration may be related to the percentage of dividing cells in populaitons of these organisms.
Production of [14C]patulin by Penicillium patulum
Authors: Nip W K , Chu F S
Published: January 2020

Factors affecting the production of [14C]patulin from [1-14C]acetate by replacement cultures of Penicillium patulum have been investigated. Incorporation of [1-14C]acetate into patulin reached a maximum with 6- to 8-day-old cultures incubated at 28 degrees C for 8 h in a replacement medium containing 0.1 M glucose, inorganic salts, and undiluted [1-14C]acetate. The specific activity of [14C]patulin obtained from this method was 34 mCi/mmol when 0.5 mCi of [1-14C]acetate was supplied to the replacement medium.
Iodination of staphylococcal enterotoxin B by use of chloramine-T
Authors: Orth D S
Published: January 2020

This report describes the conditions that are necessary for iodination of staphylococcal enterotoxin B (SEB) by use of chloramine-T. Makor Chemical Co. SEB and the two major SEB components, which were prepared by isoelectric focusing of partially purified SEB, were used in these studies. The antigenic activity of the SEB preparations was monitored by radioimmunoassay as the oxidation/reduction (O/R) potential was increased by addition of chloramine-T. The SEB preparations lost antigenic activity rapidly at pH 7.5 and room temperature when sufficient chloramine-T was added to raise the O/R potential above 250 mV. Iodinated SEB with satisfactory immunoreactivity was prepared by omitting carrier iodide from the iodination reaction mixture and by using at least 1 mg of SEB/ml, steps which made the O/R potential more stable, and by stopping the reaction before the O/R potential exceeded 250 mV. Comparison of the chloramine-T method with a lactoperoxidase/H2O2 method of iodinating SEB showed the latter to cause a greater loss of immunoreactivity.
Cell growth and catecholase production for Polyporus versicolor in submerged culture
Authors: Carroad P A , Wilke C R
Published: January 2020

Cell growth and catecholase production for Polyporus veriscolor (ATCC 12679) were studied in mechanically agitated submerged culture, as functions of temperature. The exponential-phase growth rate exhibited a maximum at 28 degrees C. Over the range of 20 degrees C to approximately 30 degrees C, both cell mass and enzyme yield factors were constant. At higher temperatures (30 to 40 degrees C) cell mass yield factor decreased and enzyme yield factor increased. Specific respiration rate of P. versicolor was determined. Thermal deactivation of catecholase was investigated between 30 and 50 degrees C, and deactivation rates were fit to an Arrhenius rate expression.
Identification of the virucidal agent in wastewater sludge
Authors: Ward R L , Ashley C S
Published: January 2020

Anaerobically digested sludge contains an agent that causes irreversible inactivation of poliovirus. It has now been shown that the agent responsible for this activity is ammonia. The effect of ammonia on poliovirus appears to be typical for picornaviruses, but reovirus, an enteric virus of another group, is quite resistant to this compound. Because ammonia is not virucidal in its charged state, it expresses significant activity only at pH values greater than 8. Therefore, increasing the pH of sludge should cause rapid inactivation of indigenous picornaviruses.
Bioassay for homogeneous parasporal crystal of Bacillus thuringiensis using the tobacco hornworm, Manduca sexta
Authors: Schesser J H , Kramer K J , Bulla L A
Published: January 2020

A method for determining the toxicity of Bacillus thuringiensis subsp. kurstaki parasporal crystal to the tabocco hornworm, Manduca sexta, is described. The use of both mortality and weight loss data have provided a highly sensitive and reproducible bioassay that can be used to compare relative toxicities of crystals from other subspecies as well as toxic components contained therein.
N-Alkane oxidation enzymes of a pseudomonad
Authors: Parekh V R , Traxler R W , Sobek J M
Published: January 2020

A nicotinamide adenine dinucleotide (NAD)-dependent n-alkane dehydrogenase and an NAD phosphate (reduced form)-dependent alkane hydroxylase have been purified from cell-free extracts of Pseudomonas sp. strain 196Aa grown anaerobically on n-alkane. The n-alkane dehydrogenase (fraction R-3), obtained as a single peak from Bio-Gel P-60, showed an overall 135-fold purification and was demonstrated by infrared spectroscopy and gas chromatography to convert n-decane to 1-decene. The alkene hydroxylase activity in the S-3 fraction, purified 167 times from diethylaminoethyl-cellulose, was shown by the same methodology to convert decene to decanol. Commercial ferredoxin has been shown to increase the alkane dehydrogenase activity. An NAD-, flavine adenine dinucleotide-, and iron-dependent alcohol dehydrogenase was demonstrated in the R-3 fraction. A mechanism for the anaerobic conversion of n-alkane to fatty acid has been proposed.
Amino acid profiles and presumptive nutritional assessment of single-cell protein from certain lactobacilli
Authors: Erdman M D , Bergen W G , Reddy C A
Published: January 2020

The amino acid profiles, modified essential amino acid (MEAA) indexes, and in vitro pepsin digestibilities were determined for single-cell protein (SCP) from certain industrially important lactobacilli. For the three parameters examined, substantial differences were seen between different Lactobacillus species and between strains with a given species. SCP from all of the lactobacilli examined appeared relatively high in MEAA indexes and pepsin digestibility. SCP from L. acidophilus 3205 and L. fermenti 3954 had the highest MEAA indexes, whereas L. bulgaricus 2217 and L. thermophilus 3863 had the highest percentage of digestible crude protein. SCP from L. plantarum strains had the lowest MEAA indexes. The essential amino acid compositions of SCP from different lactobacilli appear comparable to that of Food and Agriculture Organization reference protein and SCP from other sources.
Factors affecting nitrification in situ in a heated stream
Authors: White J P , Schwert D P , Ondrako J P , Morgan L L
Published: January 2020

Nitrification, previously shown to occur in the stream under study, ensued only when the stream received heated (28 degree C or above) discharges and was negligible when water temperatures were 17 degree C or lower. The most probable number os ammonium oxidizer in stream bed sediments exceeded intrite oxidizers by ratios of 43:1 to 1,113:1, and the average rate of ammonium oxidation in this stream, 0.50 mg of NH4-N/liter per h exceeded the rate of nitrite oxidation, 0.29 mg of NO2-N/liter per h, resulting in an accumulation of nitrite. Nitrification rates were influenced by the dissolved oxygen concentration, increasing during daylight hours and exhibiting maximum rates during the summer months.
Determination of bacterial number and biomass in the marine environment
Authors: Watson S W , Novitsky T J , Quinby H L , Valois F W
Published: January 2020

Three techniques for the measurement of bacterial numbers and biomass in the marine environment are described. Two are direct methods for counting bacteria. The first employs an epifluorescence microscope to view bacteria that have been concentrated on membrane filters and stained with acridine orange. The second uses a transmission electron microscope for observing replicas of bacteria that are concentrated on membrane filters. The other technique uses Limulus amebocyte lysate, an aqueous extract from the amebocytes of the horseshoe crab, Limulus polyphemus, to quantitate lipopolysaccharide (LPS) in seawater samples. The biomass of gram-negative (LPS containing) bacteria was shown to be related to the LPS content of the samples. A factor of 6.35 was determined for converting LPS to bacterial carbon.
Citrate, a specific substrate for the isolation of Clostridium sphenoides
Authors: Walther R , Hippe H , Gottschalk G
Published: January 2020

With a medium containing citrate as the carbon and energy source, 10 clostridial strains were isolated from various mud samples. Characterization of these strains revealed that they all belonged to the same species, Clostridium sphenoides. Strains of this organism obtained from culture collections were also able to grow citrate, whereas 15 other clostridial species tested were not. Citrate was fermented by C. sphenoides to acetate, ethanol, carbon dioxide, and hydrogen. Experiments with stereospecifically 14C-labeled citrate indicated that citrate lyase was involved in citrate degradation.
Improved procedure for crystallization of Clostridium botulinum type A toxic complexes
Authors: Sugiyama H , Moberg L J , Messer S L
Published: January 2020

A modified protocol for the preparation of botulinum type A toxic crystals is decribed. The essential change was the substitution of chromatography on diethylaminoethyl-Sephadex for the step in which toxin was precipitated with ethanol. Colored materials and nucleic acids were removed by the chromatography so that crystal lots of greater uniformity could be produced. Significantly more of toxin in the starting culture was recovered as crystals. The lots of crystals obtained initially by either the original or the modified method contained an antigen that was eliminated when the lots were recrystallized.
Comparison of Sulfite-Polymyxin-Sulfadiazine Medium and Tryptose-Sulfite-Cycloserine Medium Without Egg Yolk for Recovering
Clostridium perfringens
Authors: Orth D. S.
Published: January 2020

The overall recoveries of spores and of actively growing, heat-stressed, coldshocked, and frozen cells of five strains of
Clostridium perfringens
were significantly greater (95% confidence limits) on tryptose-sulfite-cycloserine medium without egg yolk than on sulfite-polymyxin-sulfadiazine medium.
Destruction of coliforms in water and sewage water by dye-sensitized photooxidation
Authors: Acher A J , Juven B J
Published: January 2020

A new approach to disinfection of water and sewage water, by oxidative destruction of microorganisms by photosensitization, is described. Samples of water and sewage water, to which an inoculum of fecal Escherichia coli had been added, were exposed to solar radiation in the presence of a dye sensitizer, under continuous aeration. The effects of the sensitizer methylene blue at concentrations of 0 to 10 mg/liter, different radiation times from 0 to 2 h, and sunlight intensities of 0, 68, and 2,030 muE/m2 per s were investigated. In laboratory-scale experiments, 1.3 X 10(9) coliforms in 100 ml of oxidation pond municipal sewage water containing 0.5 mg of methylene blue were destroyed in about 30 min. Similar results were obtained with nonchlorinated potable water. These results demonstrate the possibilities available for the disinfection of water and sewage water by this method.
Characterization of the predominant bacteria occurring in the rumen of goats (Capra hircus)
Authors: Dehority B A , Grubb J A
Published: January 2020

A total of 44 strains of bacteria were isolated from rumen contents of the goat. Based on morphology, Gram stain, anaerobiosis, motility, and fermentation end products, they were grouped into 11 different types. For each type, all or representative strains were characterized in detail. The type, number of strains characterized over total number of strains, and identification were as follows: type 1, 6/21, atypical Butyrivibrio fibriosolvens; type 2, 6/9, atypical Butyrivibrio fibrisolvens; type 3, 3/3, genus uncertain; type 4, 2/2, genus uncertain; type 5, 3/3, Streptoccous bovis; type 6, 1/1, Butyrivibrio fibrisolvens; type 7, 1/1, Bacteroides ruminicola subsp. ruminicola; type 8, 1/1, Bacteroides ruminicola subsp. brevis; type 9, 1/1, family Peptococcaceae, genus uncertain; type 10, 1/1, genus Bacteroides; type 11, 1/1, genus Bacteroides. About 70% of the isolated strains were classified as Butyrivibrio, which is quite high compared with previous studies in cattle on similar rations. Of the 30 strains listed as type 1 and 2, the 12 studied further were characterized as atypical Butyrivibrio fibrisolvens, which differed from the species description primarily by their inability to hydrolyze starch and lack of gas production.
General Model of Microbial Growth and Decomposition in Aquatic Ecosystems
Authors: Clesceri L. S. , Park R. A. , Bloomfield J. A.
Published: January 2020

A model capable of simulating freely suspended and attached decomposers, particulate organic matter, labile and refractory dissolved organic matter, inorganic nitrogen, and phosphate in the open-water portion of lakes is presented. Examples are given showing the utility of the model when coupled to the whole-ecosystem model CLEANER.
Effect of Cadmium on Fungi and on Interactions Between Fungi and Bacteria in Soil: Influence of Clay Minerals and pH
Authors: Babich H. , Stotzky G.
Published: January 2020

Fungi (
Rhizopus stolonifer, Trichoderma viride, Fusarium oxysporum
f. sp.
conglutinans, Cunninghamella echinulata
, and several species of
Aspergillus
and
Penicillium
) tolerated higher concentrations of cadmium (Cd) when grown in soil than when grown on laboratory media, indicating that soil mitigated the toxic effects of Cd. In soil amended with clay minerals, montmorillonite provided partial or total protection against fungistatic effects of Cd, whereas additions of kaolinite provided little or no protection. Growth rates of
Aspergillus niger
were inhibited to a greater extent by 100 or 250 μg of Cd per g in soil adjusted to pH 7.2 than in the same soil at its natural pH of 5.1. However, there were no differences in the growth rates of
Aspergillus fischeri
with 100 or 250 μg of Cd per g in the same soil, whether at pH 5.1 or adjusted to pH 7.2. Growth of
A. niger
and
A. fischeri
in a soil contaminated with a low concentration of Cd (i.e., 28 μg/g), obtained from a site near a Japanese smelter, did not differ significantly from growth in a soil collected some distance away and containing 4 μg of Cd per g. Growth of
A. niger
in sterile soil amended with 100 μg of Cd per g and inoculated with
Bacillus cereus
or
Agrobacterium tumefaciens
was reduced to a greater extent than in the same soil containing 100 μg of Cd per g but no bacteria. The inhibitory effects of
Agrobacterium radiobacter
to
A. niger
were slightly reduced in the presence of 100 μg of Cd per g, whereas the inhibitory effects of
Serratia marcescens
were enhanced.
Diluent sensitivity in thermally stressed cells of pseudomonas fluorescens
Authors: Gray R J , Ordal Z J , Witter L D
Published: January 2020

Thermally injured cells of Pseudomonas fluorescens were unable to produce colonies on Trypticase soy agar (TSA) after dilution with 0.1% peptone. Nutritional exigency could not be used as the criterion for this injury, since varying the composition of the plating medium had little effect on the number of colonies that developed. The injured cells had no requirement for compounds known to leak out during the heat treatment in order to recover. The cells did not exhibit injury if dilution preceded heat treatment on the plating medium, demonstrating that the heat treatment sensitized the cells to the trauma of dilution. Substitution of 0.1% peptone with growth medium as the diluent largely offset the previously observed drop in TSA count. Little difference in survival was observed when monosodium glutamate or the balance of the defined medium was used as the diluent. The diluent effect was ionic rather than osmotic. The presence of cations was important in maintaining the integrity of the injured cell, and divalent cations enhanced this protective effect. The role of these cations at the level of the cell envelope is discussed.
Study of inhibition of outgrowth in Bacillus cereus T by ethyl picolinate
Authors: Pandey N K , Gollakota K G
Published: January 2020

The effects of ethyl picolinate on germination, outgrowth, and sporulation of Bacillus cereus T were studied in a synthetic medium containing glucose. Ethyl picolinate specifically inhibited at two stages, outgrowth and sporulation. The initiation of germination and cell division was not affected. The inhibition of outgrowth by ethyl picolinate could be reversed by enrichment of inoculum with aspartic acid, asparagine, lysine, phenylalanine, and tyrosine among the amino acids and by oxalacetate. Nicotinic acid and nicotinamide also possessed this ability. Ethyl picolinate failed to block outgrowth when added to cultures incubated for a short time after inoculation. Enrichment of the medium with lysine plus zinc sulfate stimulated sporulation in the presence of ethyl picolinate to a significance degree.
Production of antibody against aflatoxin B1
Authors: Chu F S , Ueno I
Published: January 2020

Antibody against aflatoxin B1 was obtained after one multiple-site injection of bovine serum albumin-aflatoxin B1 conjugate into rabbits. The antibody has greatest binding efficiency for aflatoxin B1, less efficiency for B2, G1, and Q1, and least for aflatoxicol, G2, and M1. Sterigmatocystin, coumarin, and 4-hydroxycoumarin did not give a cross-reaction with the antibody. The sensitivity of the binding assay for detection of aflatoxin B1 is in the range of 0.2 to 2.0 ng per 0.5-ml sample. Detailed methods for the preparation of the conjugate, production of immune serum, and methods for antibody titer determination are described.
Microbiological Transformations of Δ
6a,10a
-Tetrahydrocannabinol
Authors: Fukuda David , Archer Robert A. , Abbott Bernard J.
Published: January 2020

A screening program was conducted to find microorganisms that catalyze transformation reactions with cannabinoids. Three hundred fifty-eight cultures, consisting of 97 bacteria, 175 actinomycetes, and 86 molds, were incubated in media containing 0.5 mg of Δ
6a,10a
-tetrahydrocannabinol (Δ
6a,10a
-THC) per ml. After 120 h of cultivation, ethyl acetate extracts of the cultures were examined by thin-layer chromatography (TLC) for transformation products. About 18% of the cultures modified Δ
6a,10a
-THC. The ability to modify the substrate did not predominate among any particular group of microorganisms. After purification, the products from three cultures were analyzed by high-resolution mass spectrometry, 100-mHz proton magnetic resonance spectrometry, ultraviolet spectrometry, and infrared spectrometry. These spectral data indicated that a
Mycobacterium
sp. oxidized Δ
6a,10a
-THC to cannabinol and a diastereomeric pair of 6a-hydroxy-Δ
10,10a
-THC isomers; a
Streptomyces
sp. and a
Bacillus
sp. oxidized Δ
6a,10a
-THC to 7-keto-Δ
6a,10a
-THC and 4′-hydroxy-Δ
6a,10a
-THC, respectively. The occurrence of these products and the presence of others that have not yet been isolated or identified indicate that microbial transformation may be a useful tool for the preparation of new cannabinoids that have desirable pharmacological properties.
Significance of Fecal Coliform-Positive
Klebsiella
Authors: Bagley Susan T. , Seidler Ramon J.
Published: January 2020

A total of 191
Klebsiella pneumoniae
isolates of human clinical, bovine mastitis, and a wide variety of environmental sources were tested for fecal coliform (FC) response with the membrane filtration and most probable number techniques. Twenty-seven
Escherichia coli
cultures of human clinical and environmental origins were also tested. Eighty-five percent (49/58) of known pathogenic
K. pneumoniae
were FC positive, compared with 16% (19/120) of the environmental strains.
E. coli
results indicated 93% (13/14) of the clinical and 85% (11/13) of the environmental strains as FC positive. There was no significant difference in the incidence of FC-positive cultures between pathogenic
Klebsiella
and
E. coli.
pH measurements of
K. pneumoniae
and
E. coli
cultures growing in
m
-FC broth at 44.5°C revealed three distinct pH ranges correlating with colony morphology. β-Galactosidase assays of
Klebsiella
and
E. coli
cultures at 44.5°C indicated all were able to hydrolyze lactose, even if they were FC negative by the membrane filtration or most probable number techniques. The FC response pattern appears stable in
K. pneumoniae.
Three pathogenic cultures showed no change in FC responses after 270 generations of growth in sterile pulp mill effluent. Since
K. pneumoniae
is carried in the gastrointestinal tract of humans and animals and 85% of the tested pathogenic strains were FC positive, the isolation of FC-positive
Klebsiella
organisms from the environment would indicate their fecal or clinical origin or both. The added fact that
K. pneumoniae
is an opportunistic pathogen of increasing importance makes the occurrence of FC-positive environmental
Klebsiella
, particularly in large numbers, a potential human and animal health hazard.
Purification and characteristics of an alginase from Alginovibrio aquatilis
Authors: Stevens R A , Levin R E
Published: January 2020

An exocellular inducible alginase from a strain of Alginovibrio aquatilis was purified 61-fold by ammonium sulfate precipitation and column chromatography on Sephadex G-150 and diethylaminoethyl-cellulose. The purified enzyme was more resistant than the crude enzyme to elevated temperatures. The monovalent cations Cs+, Rb+, K+, Na+, and Li+, in order of decreasing enzyme activation, were required for activity. The pH optimum of the purified alginase was 8.0 and its molecular weight from exclusion chromatography on Sephadex G-150 was 110,000.
Comparison of Four Selective Agars for the Isolation of Pseudomonads
Authors: Hart A. , Kite Atricia E.
Published: January 2020

Significant differences were found between Dettol (chloroxylenol) agar, nalidixic acid-cetrimide agar, and two other cetrimide-containing agars used for the isolation of small numbers of pseudomonads.
Inactivation of Poliovirus in Wastewater Sludge with Radiation and Thermoradiation
Authors: Ward Richard L.
Published: January 2020

Sludge is highly protective of poliovirus against both heat and ionizing radiation. This protection could be largely overcome when these two treatments were given simultaneously.
Butyl Rubber Stoppers Increase the Shelf Life of Prereduced, Anaerobically Sterilized Media
Authors: Fulghum Robert S. , Worthington John M.
Published: January 2020

Butyl rubber stoppers as compared with neoprene or black rubber stoppers significantly increased the shelf life of prereduced, anaerobically sterilized media for growth of obligately anaerobic bacteria.
Comparison of two direct-count techniques for enumerating aquatic bacteria
Authors: Bowden W B
Published: January 2020

Planktonic bacteria from an estuary were concentrated on membrane filters and counted with both a scanning electron microscope and an epi-illuminated fluorescent microscope. Counts on 0.2 micron Nuclepore filters (polycarbonate) were significantly higher (P less than 0.001) than counts on 0.2-micron Sartorius filters (cellulose). In contrast, there was not a statistically significant difference between the two techniques when Nuclepore filters were used (0.5 less than P less than 0.9). The average cell volume from this study area was 0.047 micron3. The estimated number of bacteria ranged from 10(6) to 10(7) bacteria per ml, representing from 4 to 40 mg of C per m3.
Sensitive Enzymatic Assay for Glucose Determination in Natural Waters
Authors: Cavari B. Z. , Phelps G.
Published: January 2020

A new enzymatic method for glucose determination is described. It allows measurement of glucose concentration as low as 10
-7
M. Such sensitivity makes this method particularly appropriate for estimation of glucose in natural-water bodies, generally without prior concentration or extraction. The method is based on the reaction between glucose and adenosine 5′-triphosphate, catalyzed by hexokinase to form glucose-6-phosphate. The amount of adenosine 5′-triphosphate consumed in this reaction, which is directly proportional to the amount of glucose present in the sample, is measured by the luciferin-luciferase assay. The optimal conditions for glucose determination by this method have been defined as follows: 20 min of incubation at 30°C, magnesium concentration of 10
-3
M, and pH in the range of 7.5 to 10.5. The specificity of the assay to different carbohydrates has also been studied. Recovery of known amounts of glucose added to Lake Kinneret water was in the range of 80 to 114%. Application of this method is demonstrated in eight monthly profiles of the glucose content in Lake Kinneret.
Spoilage association of chicken leg muscle
Authors: McMeekin T A
Published: January 2020

The ability of pure cultures of bacteria isolated from spoiling chicken leg muscle to produce strong off-odors was tested by using sterile leg muscle sections. Changes in the flora during storage and the incidence and identity of organisms capable of producing strong off-odors were noted.
Rapid detection of microbial contamination in frozen vegetables by automated impedance measurements
Authors: Hardy D , Kraeger S J , Dufour S W , Cady P
Published: January 2020

Automated impedance measurements can be used to rapidly assess whether a sample of frozen vegetables contains greater or less than 10(5) organisms per g. Microorganisms growing pureed food samples cause a change in the impedance of the medium when the organisms reach a threshold concentration of between 10(6) and 10(7) organisms per ml. Estimates of the concentration of microorganisms initially present in the food sample can be made by recording the time required for the organisms in the sample to replicate to threshold levels. In this study, the detection times for 357 samples of frozen vegetables were compared with standard plate counts for each sample. The agreement between the two methods in distinguishing samples containing more than 10(5) organisms per g was 92.6% for 257 assorted frozen vegetables and somewhat higher (93 to 96%) when separate cutoff times were used for each type of vegetable. The time required for analysis was about 5 h, compared to the 48 to 72 h required for standard plate counts.
Growth kinetics of Colpoda steinii on Escherichia coli
Authors: Drake J F , Tsuchiya H M
Published: January 2020

Colpoda steinii was grown in two-stage continuous cultures with Escherichia coli as prey species. The concentration of prey and the ciliate mean cell volume, dry weight, and number per milliliter were determined at known growth rates. Steady states were reached in the second-stage continuous cultures at all growth rates. Although changes occurred in mean cell size of the ciliates and in the number per milliliter at various growth rates, the yield of protozoan biomass per unit of prey consumed was constant at all growth rates. The data were compared with several equations proposed to describe the kinetics of protozoan growth as a function of prey density.
Thermal destruction of Clostridium botulinum spores suspended in tomato juice in aluminum thermal death time tubes
Authors: Odlaug T E , Pflug I J
Published: January 2020

The heat destruction characteristics of Clostridium botulinum spores suspended in tomato juice and phosphate buffer were determined by the survivor curve method with aluminum thermal death time tubes. Two type A strains of C. botulinum and a type B strain were evaluated. Strains A16037 and B15580 were implicated in outbreaks of botulism involving home-canned tomato products. Strain A16037 had a higher heat resistance than either 62A or B15580. The mean thermal resistance (D-values) for A16037 in tomato juice (pH 4.2) were: 115.6 degrees C, 0.4 min; 110.0 degrees C, 1.6 min; and 104.4 degrees C, 6.0 min. The mean D-values for A16037 in Sorensen 0.067 M phosphate buffer (pH 7) were: 115.6 degrees C, 1.3 min; 110.0 degrees C, 4.4 min; and 104.4 degrees C, 17.6 min. At each test temperature, the D-values were approximately three times higher in buffer than in tomato juice. The z-value for C. botulinum A16037 spores in tomato juice was 9.4 degrees C, and in buffer the z-value was 9.9 degrees C. The use of aluminum thermal death time tubes in a miniature retort system makes it possible to determine survivor curves for C. botulinum spores at 121.1 degrees C. This is possible because the lag correction factor for the aluminum tubes is only about 0.2 min, making possible heating times as short as 0.5 min.
Effect of storage time and temperature on the survival of Clostridium botulinum spores in acid media
Authors: Odlaug T E , Pflug I J
Published: January 2020

Clostridium-botulinum type A and type B spores were stored in tomato juice (pH 4.2) and citric acid-phosphate buffer (pH 4.2) at 4, 22, and 32 degrees C for 180 days. The spore count was determined at different intervals over the 180-day storage period. There was no significant decrease in the number of type A spores in either the tomato juice or citric acid-phosphate buffer stored for 180 days at 4, 22, and 32 degrees C. The number of type B spores did not decrease when storage was at 4 degrees C, but there was an approximately 30% decrease in the number of spores after 180 days of storage at 22 and 32 degrees C.
Spatial relationship of the vaginal microflora to the vaginal epithelium of female rats: scanning electron microscopy
Authors: Larsen B , Markovetz A J , Galask R P
Published: January 2020

The vaginal mucosa of ovariectomized female rats has been examined by scanning electron microscopy before and after estrogen [1,3,5(10)-estratriene-3,17beta-diol] treatment. Without estrogen stimulation vaginal colonization is minimal and the epithelium is characterized by a layer of epithelial cells covered with small microvillous-like projections. Progressive changes that were consistent with estrogenic cytoproliferative effects were seen after estrogen treatment. By post-treatment day 3 bacterial colonization was maximal and the epithelium was comprised of flat squamous cells that tended to become detached from the underlying tissue layers. Bacteria were seen in association with the intercellular borders of this tissue and occurred singly or as microcolonies. No distinct physical attachment structures were identified, although an amorphous extracellular material that may serve to attach the bacteria to the squamous epithelial cells was frequently seen.
Toxicity of Diplodia maydis to laboratory animals
Authors: Rabie C J , van Rensburg S J , Kriek N P , Lübben A
Published: January 2020

Ten strains of Diplodia maydis isolated from commercial corn samples and grown on whole yellow corn at 25 degrees C for 6 weeks were toxic to ducklings and rats. The degree of toxicity depended on the incubation period and temperature. Minimum incubation periods of 3 to 4 weeks and 6 weeks were necessary to cause mortality in ducklings and rats, respectively. Cultures incubated at 31 and 25 degrees C were much more toxic than those kept at 16 and 20 degrees C. Heat treatments at 80 to 90 degrees C destroyed most of the toxicity of moldy meal. Mild lesions of a similar histopathological nature were found in subclinically and lethally poisoned rats. These included toxic myocarditis, enteritis, focal renal tubular necrosis, degeneration and peripheral necrosis of the islets of Langerhans, and a generalized venous congestion.
Effect of Tween 80 on glucosyltransferase production in Streptococcus mutans
Authors: Umesaki Y , Kawai Y , Mutai M
Published: January 2020

Glucan production from sucrose by Streptococcus mutans OMZ 176 was stimulated approximately threefold in the presence of 0.1% Tween 80. When OMZ 176 was grown in a medium containing glucose, the glucosyltransferase level in the medium was also increased about fivefold in the presence of 0.1% Tween 80. The glucosyltransferase level increased in proportion to the logarithm of the concentration of Tween 80 in the glucose medium. Tween 80 affected neither bacterial growth nor the activity of glucosyltransferase. The appearance of glucosyltransferase in the glucose medium was inhibited immediately by chloramphenicol and actinomycin D and, after a lag, by rifampin as well. It was observed that the fatty acid composition of the cells grown with Tween 80 was altered. These results suggest that Tween 80 stimulates glucosyltransferase synthesis either directly, or indirectly by promoting glucosyltransferase secretion.
Surface-decontaminating action of glutaraldehyde in the gas-aerosol phase
Authors: Bovallius A , Anäs P
Published: January 2020

The surface disinfectant effect of glutaraldehyde in the gas-aerosol phase was investigated at different relative humidities and temperatures. At a gas-aerosol concentration of 15 to 20 mg/m3 and a relative humidity of about 80%, glutaraldehyde had a good disinfectant effect against both vegetative bacteria (decimal reduction time, less than 5 min) and bacterial spores (decimal reduction time, less than 45 min). In spite of its low volatility, glutaraldehyde was more effective than formaldehyde when the two substances were compared on an "added amount" basis.
Tenuazonic acid production by Alternaria alternata and Alternaria tenuissima isolated from cotton
Authors: Davis N D , Diener U L , Morgan-Jones G
Published: January 2020

Cultures of Alternaria alternata (three isolates) and Alternaria tenuissima (three isolates) obtained from cottonseeds and bolls were toxigenic when cultured on various laboratory media. A mycotoxin was isolated and identified as tenuazonic acid by using solvent partition, thin-layer chromatography, and instrument analyses. Toxicity was monitored with brine shrimp and chicken embryo bioassays. All cultures except A. alternata 938 produced tenuazonic acid when grown on cottonseed and on yeast extract-sucrose broth. The most toxin (266 mg/kg) was produced by A. tenuissima 843 on cottonseed.
Development of a quantitative method for detecting enteroviruses in estuarine sediments
Authors: Gerba C P , Smith E M , Melnick J L
Published: January 2020

Several investigators have reported on the detection of enteric viruses in marine sediments, but none determined the efficiency of their methods and only limited volumes of sediment were sampled. The purpose of this investigation was to develop a quantitative method for detecting enteroviruses in marine sediments so that their relative proportion to viruses freely suspended in estuarine water could be more accurately determined. Poliovirus was found to adsorb readily to natural marine sediments collected along the Texas Gulf coast. A number of substances were evaluated for their ability to elute adsorbed viruses. A solution of 10% fetal calf serum adjusted to pH 10.5 and 0.05M ethylenediaminetetraacetate (pH 11.0) were found to be the best eluents. Using ethylenediaminetetraacetate as an eluent, it was possible to elute virus from large volumes of sediment and reconcentrate the sediment eluate into an economically assayable volume (30 to 50 ml). Poliovirus could be recovered from the sediment with an overall efficiency of 50%. This method was found to be satisfactory for the recovery of naturally occurring animal viruses in estuarine sediments from the upper Texas Gulf coast.
Parathion utilization by bacterial symbionts in a chemostat
Authors: Daughton C G , Hsieh D P
Published: January 2020

A continuous-culture device was used to select and enrich for microorganisms, from sewage and agricultural runoff, that were capable of using the organophosphorus insecticide parathion as a sole growth substrate. Parathion was dissimilated by the highly acclimated symbiotic activities of Pseudomonas stutzeri, which non-oxidatively and cometabolically hydrolyzed the parathion to ionic diethyl thiophosphate and p-nitrophenol, and P. aeruginosa, which utilized the p-nitrophenol as a sole carbon and energy source. Ionic diethyl thiophosphate was found to be inert to any transformations. Methyl parathion was dissimilated in an analogous way. The device functioned as a chemostat with parathion as the growth-limiting nutrient, and extraordinarily high dissimilation rates were attained for parathion (8 g/liter per day) and for p-nitrophenol (7 g/liter per day). This is the first report of parathion utilization by a defined microbial culture and by symbiotic microbial attack and of dissimilation of an organophosphorus pesticide in a chemostat.
Alternative Replica Plating Technique
Authors: Lindström E. Börje
Published: January 2020

A new technique for picking bacterial colonies and a new type of replicator are described.
Oxygen demand by lipid-accumulating yeasts in continuous culture
Authors: Ratledge C , Hall M J
Published: January 2020

Specific oxygen uptake rates [Q(02)] were highest when Candida 107 and Rhodotorula gracilis grew at their maximum dilution rates. In nitrogen-limited medium, which encourages lipid accumulation, Q(02) values of both yeasts decreased as the dilution rate was lowered.
Amylase production by thermomonospora curvata
Authors: Stutzenberger F , Carnell R
Published: January 2020

Thermomonospora curvata produces an extracellular inducible amylase which does not accumulate products repressive to cellulase production during growth on starch-cellulose ratios similar to those of compost.
pH Measurements of Agar Culture Media by Using a Flat-Bottom Electrode
Authors: Gorski Theodore W. , Ritzert Roger W.
Published: January 2020

A new design, flat-bottom combination pH electrode was evaluated for utility in determining the pH of prepared agar media by surface contact of the electrode with the agar media.
Reduction of fensulfothion to fensulfothion sulfide by Klebsiella pneumoniae
Authors: Wood P A , MacRae I C
Published: January 2020

A cell suspension of Klebsiella pneumoniae converted the organophosphorus pesticide fensulfothion to a product that was shown by chemical oxidation, gas-liquid chromatography, infrared spectrophotometry, and mass spectrometry to be fensulfothion sulfide. Further alteration of this metabolite was not noted.
Effect of monensin on rumen metabolism in vitro
Authors: Van Nevel C J , Demeyer D I
Published: January 2020

The effect of Monensin (Rumensin, Eli Lilly & Co.) in incubations with mixed rumen microorganisms metabolizing carbohydrate or protein substrates was investigated. Monensin partly inhibited methanogenesis and increased propionate production, although the effect was not always statistically significant. Incubations with substrates specific for methane bacteria suggest that inhibition of methanogenesis by Monensin was not due to a specific toxic action on the methanogenic flora, but rather to an inhibition of hydrogen production from formate. Total and net microbial growth were considerably decreased by addition of Monensin, although the amount of substrate fermented was not altered, resulting in lowered values of microbial growth efficiency. In incubations with casein, Monensin lowered protein degradation in line with a lowered ammonia production, whereas a slight accumulation of alpha-amino nitrogen was observed. The results suggest that besides an influence of Monensin on the rumen carbohydrate fermentation pattern, another reason for the beneficial effects observed in vivo might be decreased food protein degradation in the rumen, altering the final site of protein digestion in the animal. Also, the possibility of a decrease in rumen microbial growth efficiency has to be considered when using Monensin as a food additive.
Thermal inactivation of ileal loop-reactive Clostridium perfringens type A strains in phosphate buffer and beef gravy
Authors: Bradshaw J G , Peeler J T , Twedt R M
Published: January 2020

The thermal resistance of spore crops produced from each of two ileal loop-reactive strains of Clostridium perfringens type A was determined in two suspending vehicles consisting of 0.067 M (pH 7.0) phosphate buffer and a commercial beef gravy. D115.6 values obtained in buffer and enumerated after pretreatment with sodium ethylenediaminetetraacetate and recovery in plating medium containing lysozyme were two- to threefold greater than those obtained without this treatment. D115.6 values obtained with beef gravy were less than those obtained in buffer with or without lysozyme; however, the D98.9 and D104.4 values were 1.3 to 2 times greater than those obtained in buffer with lysozyme. The z values were within the ranges reported by previous investigators.
Weight Increase of Cotton Fibers During Swelling in Alkali as a Sensitive Measure of Cellulose Degradation in Ruminal Fluid
Authors: Simpson Marion E. , Marsh Paul B. , Merola George V.
Published: January 2020

Weight increase of cotton fiber in an 18% NaOH solution, termed “alkali-centrifuge” or “AC” value, was measured after incubation of either 1 g or 100 mg of the fiber in ruminal fluid. The AC response was a sensitive measure of cellulolytic activity. Thus, fiber incubated at 21 and 51°C exhibited major AC increases even when direct weight losses of the unswollen fiber were less than 2%. Similarly, progressive additions of acetic acid to ruminal fluid progressively depressed both AC response and direct weight loss, but the former was still easily measurable when the latter was not. In tightly closed, completely filled vials with high ratio of ruminal fluid to sample, AC increased greatly and rapidly, i.e., in 6 h. This time could be further reduced to 2 h by overnight “preincubation” of the ruminal fluid with cotton fiber before starting the test incubation. Certain surfactants used to aid wetting of the fiber had a low but measurable potency in inhibiting cellulose digestion, but other surfactants were non-inhibitory. The AC response was maintained when ruminal fluid was diluted with an equal amount of McDougall's “artificial saliva” solution.
Isolation and purification of a granulosis virus from infected larvae of the Indian meal moth, Plodia interpunctella
Authors: Tweeten K A , Bulla L A , Consigli R A
Published: January 2020

A procedure was developed for purification of a granulosis virus inclusion body produced in vivo in the Indian meal moth, Plodia interpunctella (Hübner). Purification was accomplished by differential centrifugation, treatment with sodium deoxycholate, and velocity sedimentation in sucrose gradients. The adequacy of the procedure was confirmed by mixing experiments in which uninfected, radioactively labeled larvae were mixed with infected, unlabeled larvae. After purification, the virus was shown to be free of host tissue, to retain its physical integrity, and to be highly infectious per os. Preparations of purified virus consisted of homogeneous populations of intact inclusion bodies (210 by 380 nm) whose buoyant density was 1.271 g/cm3 when centrifuged to equilibrium in sucrose gradients. Electron microscopy of thin-sectioned virus or of virus sequentially disrupted on electron microscope grids demonstrated three components: protein matrix, envelope, and nucleocapsid.
Production of uricase by Candida tropicalis using n-alkane as a substrate
Authors: Tanaka A , Yamamura M , Kawamoto S , Fukui S
Published: January 2020

Production of uricase (urate oxidase, EC 1.7.3.3) by n-alkane-utilizing Candida tropicalis pK233 was studied. Although the yeast showed very low enzyme productivity under growing conditions on glucose or an n-alkane mixture (C10 to C13) (less than 2 U/g of dry cells), enzyme formation was enhanced markedly in an induction medium consisting of potassium phosphate buffer, MgSO4, uric acid, and an n-alkane mixture (47 U/g of dry cells) or glucose (21 U/g of dry cells). Of the carbon sources tested, the n-alkane mixture was the most suitable for enzyme production. Appropriate aeration also stimulated uricase formation. In addition to uric acid, xanthine, guanine, adenine, and hypoxanthine were also effective for inducing uricase. Under optimum conditions, the maximum yield of the enzyme was 91 U/g of dry cells. Uricase thus induced was localized in the microbodies of the yeast.
Cholesterol-reducing bacterium from human feces
Authors: Sadzikowski M R , Sperry J F , Wilkins T D
Published: January 2020

An anaerobic, gram-positive diplobacillus that reduces cholesterol to coprostanol was isolated from human feces and rat cecal contents. The isolates closely resemble a cholesterol-reducing organism isolated by Eyssen et al. (H. Eyssen et al., Eur. J. Biochem. 36:412-421, 1973) from a rat's cecum. These organisms would not form colonies and were isolated and cultivated in an anaerobic medium containing homogenized pork brains (naturally high in cholesterol). These organisms require free or esterified cholesterol for growth. They were isolated by serially diluting feces or cecal contents and inoculating brain medium. Colony-forming organisms, which did not reduce cholesterol, were eliminated by addition of inhibitory agents to the brain medium cultures. This serial dilution procedure was performed until a pure culture of a cholesterol-reducing organism was obtained.