bluuebunny/crossref_metadata_2025 huggingface dataset:
Emetic and refusal activity of deoxynivalenol to swine
Authors: Forsyth D M , Yoshizawa T , Morooka N , Tuite J
Published: January 2020

The minimum emetic dose of deoxynivalenol to swine weighing 9 to 10 kg was 0.05 mg/kg of body weight intraperitoneally and 0.1 to 0.2 mg/kg orally. There was no emesis by undosed pigs consuming vomitus from pigs orally dosed with deoxynivalenol or penned with such pigs without access to vomitus. Analysis by gas-liquid chromatography of a sample of Gibberella zeae-infected corn containing about 25% visually damaged kernels indicated 12 ppm of deoxynivalenol. Deoxynivalenol added to feed reduced feed consumption of 20- to 45-kg pigs, ranging from a 20% decrease with 3.6 ppm to 90% reduction with 40 ppm. Loss in weight was associated with feed refusal. Feed refusal, however, was much greater for naturally infected corn samples than for feeds with equal concentrations of the pure compound added, indicating the involvement of an additional factor(s) in the swine refusal response.
Inactivation of enteric viruses in wastewater sludge through dewatering by evaporation
Authors: Ward R L , Ashley C S
Published: January 2020

The effect of dewatering on the inactivation rates of enteric viruses in sludge was determined. For this study, water was evaporated from seeded raw sludge at 21 degrees C, and the loss of viral plaque-forming units was measured. Initial results with poliovirus showed that recoverable infectivity gradually decreased with the loss of water until the solids content reached about 65%. When the solids content was increased from 65 to 83%, a further, more dramatic decrease in virus titer of greater than three orders of magnitude was observed. This loss of infectivity was due to irreversible inactivation of poliovirus because viral particles were found to have released their RNA molecules which were extensively degraded. Viral inactivation in these experiments may have been at least partially caused by the evaporation process itself because similar effects on poliovirus particles were observed in distilled water after only partial loss of water by evaporation. Coxsackievirus and reovirus were also found to be inactivated in sludge under comparable conditions, which suggests that dewatering by evaporation may be a feasible method of inactivating all enteric viruses in sludge.
Epichloë typhina from toxic tall fescue grasses
Authors: Bacon C W , Porter J K , Robbins J D , Luttrell E S
Published: January 2020

Epichloë typhina, a clavicipitaceous systemic phytopathogen, was isolated from two varieties and three hybrids of tall fescue (Festuca arundinaceae). The morphology of the fescue isolates was compared with E. typhina isolated from bent grass (Agrostis perennans). In all isolates, conidia were identical and were typical of E. typhina. In fescue grasses the endophyte failed to produce stromata, but on bent grass the fungus seasonally produced stromata, typical of the genus. Cattle grazing the fescue grasses showed signs of the fescue toxicity syndrome, the E. typhina was found in frequencies of 100%; in grasses from pastures in which cattle showed no signs of the syndrome, frequencies were 0 to 50%. Nutritional factors in vitro were more complex for the isolates from fescue than for the isolate from bent grass. These studies suggested that E. typhina includes biotypes that might be involved in the toxicity syndrome. The fescue biotypes grew poorly on media, and yields were inadequate for toxicity studies. However, the bent grass isolate grew well on three media, and extracts from two of these were toxic to chicken embryos. All isolates produced in vitro the nontoxic fungal steroid tetraenone [ergosta-4,6,8(14),22-tetraen-3-one], which has been isolated from toxic fescue grasses.
Nitrogen fixation, denitrification, and pleomorphic growth in a highly pigmented Spirillum lipoferum
Authors: Eskew D L , Focht D D , Ting I P
Published: January 2020

A strain of Spirillum lipoferum with intense red pigmentation was isolated from the roots of Cynodon dactylon "Coastal." This isolate vigorously reduced acetylene when grown in N-free, Na-malate, semisolid agar, and it was identical to S. lipoferum strain SP7 by standard taxonomic tests. Both S. lipoferum SP7 and the C. dactylon root isolate displayed the unique features of being denitrifiers as well as N2 fixers. The N2-dependent growth curve was biphasic: cells in younger cultures showed the characteristic spiral shape and motility, but those in older cultures developed larger, nonmotile, cystlike forms. Nitrogenase activity seemed associated only with younger spiral forms. The red pigment may be a b- or c-type cytochrome. The strong red color, which this strain develops, could be used as a marker in evaluating soil inoculation experiments.
Problems of the Acetylene Reduction Technique Applied to Water-Saturated Paddy Soils
Authors: Lee K. K. , Watanabe I.
Published: January 2020

The acetylene reduction assay for the measurement of N
2
fixation in a water-saturated paddy soil is limited by the slow diffusion of acetylene and ethylene. In laboratory incubation tests, vigorous shaking after the assay period is needed to release ethylene into the gas within the assay vials. Shaking prior to the incubation is also effective for dissolving acetylene in the water-saturated soil. However, a water-saturated soil depth of less than 10 mm during incubation is recommended. In field assays, some amounts of ethylene remain in the water-saturated soil phase of the acetylene reduction assay chamber, but stirring the water-saturated soil before sampling reduces the amount of ethylene remaining in soil. Evidence of a downward movement of acetylene and an upward movement of ethylene through rice plants was obtained. Because of the rapid transfer of acetylene to rice plant roots, an in situ acetylene reduction assay covering a rice hill is likely to detect nitrogen fixation in the proximity of roots where acetylene is easily accessible. Acetylene introduction to the water-saturated soil phase prior to assay did not greatly increase the acetylene reduction rate. Carbon dioxide enrichment in the assay chamber did not enhance nitrogen fixation in a paddy including rice and algae during a 1-day cycle.
Production of thermophilic actinomycete-hay aerosols for use in experimental hypersensitivity pneumonitis
Authors: Burrell R , McCullough M J
Published: January 2020

An investigation of the factors that influence the production of dense aerosols of Micropolyspora faeni and Thermoactinomyces vulgaris from hay cultures revealed that the density, freshness, and moisture content of the hay were important influences. Dry aerosols were produced under optimum conditions from hay cultures of either actinomycete and from sterile hay for inhalation challenges to unimmunized rabbits. Depressions in arterial oxygen tensions and hemolytic complement were monitored after such challenge. This investigation showed that hay cultures are capable of inciting a hypersensitivity-like reaction in the lungs, even in the absence of immunization to the organisms contained within the hay, but the entire hypersensitivity reaction cannot be attributed to M. faeni and T. vulgaris alone. Hay itself or other microbial or chemical components appear to have some heat-stable component that possibly contributes to the pathogenesis of the disease.
Performance characteristics of a new photometer with a moving filter tape for luminescence assay
Authors: Picciolo G L , Chappelle E W , Thomas R R , McGarry M A
Published: January 2020

The performance characteristics of a new photometer that incorporated a reaction system consisting of a movable filtration tape have been studied for use with the firefly luciferase assay for adenosine 5'-triphosphate. Precision, linearity, and sensitivity are given for measuring a graded series of constant-light emitters, concentrations of adenosine 5'-triphosphate, and washed bacterial cells. Precision ranged from 1 to 10% coefficient of variation. The coefficient of correlation was 0.9985 for 7 X 10(8) to 7 X 10(3) bacteria per ml; however, the accuracy decreased at the low levels. The sample processing time was 2 min for a 1-ml sample. This instrument shows potential for many applications in quantitating small numbers of organisms, e.g., pollution, water monitoring, and clinical infection detection.
Influence of CH4 production by Methanobacterium ruminantium on the fermentation of glucose and lactate by Selenomonas ruminantium
Authors: Chen M , Wolin M J
Published: January 2020

A method is described for increasing the production of H2 from glucose or lactate by Selenomonas ruminantium by sequential transfers in media containing pregrown Methanobacterium ruminantium. The methanogen uses the H2 formed by the selenomonad to reduce CO2 to CH4. Analysis of fermentation products from glucose showed that lactate was the major product formed from glucose by S. ruminantium alone. Several sequential transfers in the presence of the methanogen caused a marked decrease in lactate production, which was accompanied by an increase in acetate. When lactate was the fermentation substrate, S. ruminantium alone produced propionate, acetate, and CO2. Addition to the pregrown methanogen in the sequential transfer procedure caused a significant decrease in the production of propionate and an increase in acetate formed from lactate. These results are interpreted in terms of the influence of H2 utilization by the methanogen on the production of H2 versus lactate or propionate from reduced pyridine nucleotides by S. ruminantium.
Factors Affecting Infection of
Scenedesmus obliquus
by a
Chytridium
sp. in Sewage Oxidation Ponds
Authors: Abeliovich Aharon , Dikbuck Sarah
Published: January 2020

In a high-rate oxidation pond, 0.1 to 1.0% of the algal population of
Scenedesmus obliquus
was found to be infected by a chytrid. When suitable conditions developed, these infections burst into massive epidemics that killed most of the algae. The major factors triggering massive infections were optimal oxygen concentration and low concentrations of potassium and magnesium cations. The fungicide Benomyl was effective in preventing infection at a concentration of 1 mg/liter.
Upper boundary of the biosphere
Authors: Imshenetsky A A , Lysenko S V , Kazakov G A
Published: January 2020

By using meterological rockets fitted with specially designed analyzers, samples for microbiological investigation have been taken. The analyzer design prevented extraneous microorganisms from penetrating into the analyzer. Before being used, the analyzers were sterilized with high gamma-ray doses. For the first time microorganisms have been detected in the mesosphere at an altitude of 48 to 77 km. The microorganisms are microscopic fungi having black conidia or spores (Circinella muscae, Aspergillus niger, Papulaspora anomala) and one species forming green conidia (Penicillium notatum). Colonies of Mycobacterium luteum and Micrococcus albus have also grown. Five of the six species have synthesized pigments. The presence of pigmented microbial forms leads us to believe that natural selection is occurring in the mesosphere because cells possessing chromogenous pigments (carotenoids, melanins) are more resistant to ultraviolet-ray action. A greater number of microorganisms have been registered in the mesosphere during dust storms than in the absence of strong winds.
Reliable sampling method for analysis of the ecology of the human alimentary tract
Authors: Macy J M , Yu I , Caldwell C , Hungate R E
Published: January 2020

An intubation method has been developed that allows removal of a sample of human intestinal fluid within a short period of time, that avoids contamination, and that minimizes exposure of the sample to air. Preliminary results obtained with this method have shown that the stomach and duodenum are essentially sterile and that the bacterial population present in the remainder of the small intestine is similar to that described by previous workers except that Veillonella species were encountered frequently and Haemophilus species were also detected in the lower jejunum and ileum of some individuals.
Toxicity of Bacillus thuringiensis spores to the tobacco hornworm, Manduca sexta
Authors: Schesser J H , Bulla L A
Published: January 2020

Toxicity of Bacillus thuringiensis spores to the tobacco hornworm, Manduca sexta, is described. The numbers of larvae killed were in relation to spore dry weight. At a surface application of 6.8 ng/cm2, there was an 85 percent survival, but less than 50 percent survived at 68.2 ng/cm2. Striking similarity of spores to parasporal crystals is revealed by slope of mortality curves, inhibition of stadial growth, and 50 percent lethal dose values based on protein content.
Nitrogen fixation (acetylene reduction) associated with roots of winter wheat and sorghum in Nebraska
Authors: Pedersen W L , Chakrabarty K , Klucas R V , Vidaver A K
Published: January 2020

Root segments and root-soil cores (6.5-cm diameter) from fields and nurseries of winter wheat and sorghum were tested for N2 fixation by using the acetylene reduction assay. Wheat samples (approximately 1,200) from 109 sites generally had low or no activity (0 to 3.1 nmol of C2H4 produced per h per g [dry weight] of root segments), even after 24 h of incubation. However, a commercial field of Scout 66, located in western Nebraska, exhibited appreciable activity (290 nmol of C2H4 produced per h per g [dry weight] of root segments). Of 400 sorghum lines and crosses, grain sorghums (i.e., CK-60A, Wheatland A, B517, and NP-16) generally exhibited higher nitrogenase activity than forage sorghums or winter wheats. CK-60A, a male sterile grain sorghum, was sampled at four locations and had the most consistent activity of 24 to 1,100 nmol of C2H4 produced per h per core. The maximum rate extrapolated to 2.5 g of N per hectare per day. Numerous N2-fixing bacterial isolates were obtained from wheat and sorghum roots that exhibited high nitrogenase activity. Most isolates were members of the Enterobacteriacae, i.e., Klebsiella pneumoniae, Enterobacter cloacae, and Erwinia herbicola.
Residual viruses in pork products
Authors: McKercher P D , Hess W R , Hamdy F
Published: January 2020

Partly cooked canned hams and dried pepperoni and salami sausages were prepared from the carcasses of pigs infected with African swine fever virus and pigs infected with hog cholera virus. Virus was not recovered from the partly cooked canned hams; however, virus was recovered in the hams before heating in both instances. Both African swine fever virus and hog cholera virus were recovered from the dried salami and pepperoni sausages, but not after the required curing period.
Adhesion of bacteria to epithelial cell surfaces within the reticulo-rumen of cattle
Authors: McCowan R P , Cheng K J , Bailey C B , Costerton J W
Published: January 2020

Blocks of tissue were removed from various locations in the bovine digestive tract and fixed and processed for transmission and scanning electron microscopy by techniques that retained adherent bacteria. The distribution of bacteria on the surface of epithelial cells was examined by scanning electron microscopy. This showed intermittent colonization of the epithelia with the formation of occasional microcolonies of morphologically similar bacterial cells. Transmission electron microscopy of ruthenium red-stained material showed the presence of both the glycocalyx of the bovine epithelial cells and fibrous carbohydrate coats surrounding adherent bacteria. The carbohydrate coats appeared to mediate the attachment of bacteria to the epithelium, to food particles, and to each other so that microcolonies were formed. Careful examination of the bacterial colonization of keratinized cells in the process of being sloughed from the surface of the stratified squamous epithelium of the rumen showed that these dead cells were digested by adherent bacteria of a limited number of morphological types. The spatial relationship of this mixed, adherent, microbial population to living and dead epithelial cells and to food particles indicates that digestive processes of some importance may be accomplished by this stationary component of the microbial flora of the digestive tract.
Multichannel electrochemical microbial detection unit
Authors: Wilkins J R , Young R N , Boykin E H
Published: January 2020

A compact multichannel unit for electrochemical detection of microorganisms that automatically displays detection time length is described. This unit was successfully tested with various members of the Enterobacteriaceae group.
Catechol and phenol degradation by a methanogenic population of bacteria
Authors: Healy J B , Young L Y
Published: January 2020

An anaerobic population of bacteria became acclimated to catechol and phenol in 32 and 18 days, respectively. Evidence from carbon balance measurements indicates that the aromatic ring is cleaved and that the products are stoichiometrically fermentable to methane and carbon dioxide.
Discrimination between oral streptococci by pyrolysis gas-liquid chromatography
Authors: Stack M V , Donoghue H D , Tyler J E
Published: January 2020

Washed organisms, including strains of Streptococcus mitior, S. mutans, and S. sanguis, were examined by curie-point pyrolysis gas-liquid chromatography. A linear discriminant function based upon three items from the output data was adequate for segregating the strains according to species. Strains with intermediate properties were also encountered. Sources of variability in cultures were evaluated, chromatographic performance was maintained throughout the investigation, and matching performance from a duplicate pair of chromatographic columns was demonstrated.
Usefulness of the stomacher in a microbiological regulatory laboratory
Authors: Andrews W H , Wilson C R , Poelma P L , Romero A , Rude R A , Duran A P , McClure F D , Gentile D E
Published: January 2020

The relative efficiency of the Waring blender, the Stomacher 400, and the Stomacher 3500 for preparing food samples for microbiological analysis was studied. Comparative aerobic plate count (APC) values were determined on 671 samples, representing 30 categories of foods. Of the 26 categories of nonfatty foods, the blender gave significantly higher geometric mean APC values than those given by the Stomacher 400 and the Stomacher 3500 in 65 and 69 percent of the categories, respectively. In a comparison of the two Stomacher models, the Stomacher 400 gave significantly higher geometric mean APC values than these given by the Stomacher 3500 in 73 percent of the food categories. Addition of Tween 80 to four categories of fatty foods at concentrations of 0.5, 1.0, and 2.0 percent did not raise the APC values given by either model of stomacher to the levels given by the Waring blender. Overall, the efficiency of both models of Stomacher, relative to the blender and to each other, was specific and depended upon the particular food being analyzed.
Persistence of
Rhizobium japonicum
on the Soybean Seed Coat Under Controlled Temperature and Humidity
Authors: Davidson F. , Reuszer H. W.
Published: January 2020

When
Rhizobium japonicum
strain 61A68 was added to surface-sterilized soybean (
Glycine max
) seed along with 12 different coating materials, a definite effect of temperature upon survival was observed both with and without coating materials. At a storage temperature of 15°C and 50 ± 5% relative humidity, from 0.9 to 14.1% of the original inoculum survived for 3 weeks. At 22.5°C, from 0.5 to 7.2% of the original inoculum survived. At 30°C, from 0.1 to 1.6% of the original inoculum survived. The data indicated that extremely large numbers of
R. japonicum
would have to be added to the seed to have numbers adequate for nodulation survive for 3 weeks of storage at ordinary temperatures.
Differentiation of Salmonella Serotypes by pyrolysis-gas-liquid chromatography of cell fragments
Authors: Emswiler B S , Kotula A W
Published: January 2020

Pyrolysis-gas-liquid chromatography (PGLC) of whole cells and cell fragments was used to differentiate 10 Salmonella serotypes. Lyophilized samples (200 microgram) of whole cells, cell walls, flagella, and deoxyribonucleic acid from each serotype were analyzed in duplicate by PGLC. Pyrochromatograms recorded as pyrolytic elution patterns represented thermal fragmentation products of the samples. Mathematical expressions of percent similarity and percent conformity were calculated for all possible pair combinations of the 10 serotypes. Stepwise discriminant analysis of the PGLC data showed that 100 percent correct classification of the 10 serotypes was possible from the flagella or deoxyribonucleic acid pyrochromatograms. The classification matrix of the whole-cell data showed a 90 percent correct classification. PGLC of cell fragments may provide useful information for taxonomic studies of Salmonella and other microorganisms.
Selective enrichment of aromatic amino acid auxotrophs in Hansenula polymorpha
Authors: Sanchez S , Cea A , Flores M E
Published: January 2020

Aromatic amino acid auxotrophs of the methanol-utilizing yeast Hansenula polymorpha were effectively selected by the use of nystatin and a medium that inhibits the growth of tyrosine auxotrophs. The procedure resulted in a frequency of aromatic auxotrophs of 2% of survivors and an enrichment of 20-fold. The new procedure also takes less time than traditional procedures. Of the auxotrophic mutants isolated, two-thirds required tyrosine and the remainder were tyrosine-phenylalanine double auxotrophs.
Recovery of Poly-β-Hydroxybutyrate from Estuarine Microflora
Authors: Herron Jean S. , King John D. , White David C.
Published: January 2020

Poly-β-hydroxybutyrate (PHB) is a uniquely procaryotic endogenous storage polymer whose metabolism has been shown to reflect environmental perturbations in laboratory monocultures. When hydrolyzed for 45 min in 5% sodium hypochlorite, PHB can be isolated from estuarine detrital microflora in high yield and purified free from non-PHB microbial components. Lyophilization of frozen estuarine samples shortens the exposure time to NaOCl necessary for maximal recovery. Lyophilized samples of hardwood leaves,
Vallisneria
, and the aerobic upper millimeter of estuarine muds yielded PHB. The efficiency of incorporation of sodium [1-
14
C]acetate into PHB is very high and is stimulated by aeration. PHB was not recovered from the anaerobic portions of sediments unless they were aerated for a short time. Levels of PHB in the detrital microbial community do not correlate with the microbial biomass as measured by the extractible lipid phosphate, suggesting that PHB-like eucaryotic endogenous storage materials may more accurately reflect the metabolic status of the population than its biomass.
Survival and resistance of Trichophyton mentagrophytes arthrospores
Authors: Hashimoto T , Blumenthal H J
Published: January 2020

The effects of several physical and chemical agents on the survival of Trichophyton mentagrophytes arthrospores were investigated. Although arthrospores of this dermatophyte were highly resistant to chilling and freezing, they were extremely susceptible to moderate heat (above 50 degrees C) and desiccation. This high susceptibility could be significantly reduced when they were dried in the presence of exogenous proteins. These arthrospores were markedly susceptible to glutaraldehyde. They appeared to be significantly more resistant than their hyphal counterparts to common antimycotics such as clotrimazole, griseofulvin, miconazole nitrate, and nystatin. Clinical and epidemiological implications of these observations are discussed.
Nutritional Requirements of
Selenomonas ruminantium
for Growth on Lactate, Glycerol, or Glucose
Authors: Linehan B. , Scheifinger C. C. , Wolin M. J.
Published: January 2020

The nutritional requirements of
Selenomonas ruminantium
HD4 for growth on glucose, glycerol, or lactate were investigated to clarify the results of previous studies and to relate the nutrition of the organism to its physiology. The organism required
l
-aspartate, CO
2
,
p
-aminobenzoic acid, and biotin for growth on a lactate-salts medium that contained small amounts of dithiothreitol. Aspartate could be replaced by
l
-malate or fumarate but not by succinate or
l
-asparagine. Requirements for growth with glycerol as an energy source were similar, except that aspartate was not required. With glucose as the energy source, neither aspartate nor
p
-aminobenzoic acid was required, but a requirement for volatile fatty acids, which could be met by
n
-valerate, was observed. CO
2
was required for growth on lactate or glycerol but not on glucose on complex media containing Trypticase and yeast extract. Sulfide could be used as the sole source of sulfur.
Estimation of Fermentation Biomass Concentration by Measuring Culture Fluorescence
Authors: Zabriskie D. W. , Humphrey A. E.
Published: January 2020

The fluorescence of a fermentation culture was studied for its application as an estimator of biomass concentration. The measurement was obtained by irradiating the culture with ultraviolet light (366 nm) through a glass window and detecting fluorescent light at the window surface at 460 nm. It was estimated that over one-half of the fluorescent material was intercellular reduced nicotinamide adenine dinucleotide, with the remainder being reduced nicotinamide adenine dinucleotide phosphate and other unidentified intercellular and extracellular fluorophores. The culture fluorescence was found to be a function of biomass concentration, together with environmental factors, which presumably act at the cellular metabolic level to modify intercellular reduced nicotinamide adenine dinucleotide pools (e.g., dissolved oxygen tension, energy substrate concentration, and inhibitors). When these environmental conditions were controlled, a linear relationship was obtained between the log of the biomass concentration and the log of the fluorescence. Under these conditions, this relationship has considerable potential as a method to provide real-time biomass concentration estimates for process control and optimization since the fluorescence data is obtained on line. When environmental conditions are variable, the fluorescence data may be a sensitive index of overall culture activity because of its dependence on intercellular reduced nicotinamide adenine dinucleotide reserves and metabolic rates. This index may provide information about the period of maximum specific productivity for a specific microbial product.
Production of penicillic acid and patulin by an atypical Penicillium roqueforti isolate
Authors: Olivigni F J , Bullerman L B
Published: January 2020

Simultaneous production of penicillic acid and patulin by an atypical strain of Penicillium roqueforti isolated from cheddar cheese is reported. Mycotoxin production was confirmed by thin-layer and gas-liquid chromatography and by ultraviolet, infrared, and mass spectral analyses. Culture extracts were toxic to Bacillus megaterium and chicken embryos. Commercial strains of P. roqueoforti used in production of blue-veined cheeses were shown not to produce penicillic acid and patulin.
Spatial relationship of the genital microflora to the vaginal epithelium of femal rats: transmission electron microscopy
Authors: Larsen B , Markovetz A J , Galask R P
Published: January 2020

Bacterial associations with vaginal epithelium were examined by transmission electron microscopy in castrate rats before and after estrogen treatment. Bacteria were associated with keratinized epithelium and appeared to be most abundant on exfoliated vaginal cells.
Method for Adenosine 5′-Triphosphate Measurement on Coke Waste Activated Sludge
Authors: Russell James , Gauthier Joseph J.
Published: January 2020

Measurement of adenosine 5′-triphosphate (ATP) in coke waste activated sludge can provide a simple method for estimating the levels of viable microbes in the sludge. However, the presence of inhibitors such as phenol in the sludge interferes when the luciferin-luciferase method is used to measure ATP. These inhibiting substances can be removed from the sludge before extraction of ATP by washing the cells with dilute sodium dodecyl sulfate.
Computer-assisted identification of anaerobic bacteria
Authors: Kelley R W , Kellogg S T
Published: January 2020

A computer program was developed to identify anaerobic bacteria by using simultaneous pattern recognition via a Bayesian probabilistic model. The system is intended for use as a rapid, precise, and reproducible aid in the identification of unknown isolates. The program operates on a data base of 28 genera comprising 238 species of anaerobic bacteria that can be separated by the program. Input to the program consists of biochemical and gas chromatographic test results in binary format. The system is flexible and yields outputs of: (i) most probable species, (ii) significant test results conflicting with established data, and (iii) differential tests of significance for missing test results.
Influence of water activity on the production of extracellular enzymes by Staphylococcus aureus
Authors: Troller J A , Stinson J V
Published: January 2020

Two enterotoxigenic strains of Staphylococcus aureus were examined for their ability to produce a number of extracellular enzymes at various water activity (alphaw) levels. Supernatant, dialyzed culture media were analyzed for total and relative levels of enzyme activity. With the exception of protease, enzyme activity was greatest in spent media obtained from cultures grown at 0.996 alphaw, the highest level tested. Enzyme activity in spent media from an enterotoxin B-producing strain was generally more sensitive to alphaw reduction than activity from an enterotoxin A-producing strain. Unlike the other enzymes assayed, acid and alkaline protease activities were greatest when the organism was grown at 0.94 alphaw.
Biological Dinitrogen Fixation (Acetylene Reduction) Associated with Florida Mangroves
Authors: Zuberer D. A. , Silver W. S.
Published: January 2020

Biological dinitrogen fixation in mangrove communities of the Tampa Bay region of South Florida was investigated using the acetylene reduction technique. Low rates of acetylene reduction (0.01 to 1.84 nmol of C
2
H
4
/g [wet weight] per h) were associated with plant-free sediments, while plant-associated sediments gave rise to slightly higher rates. Activity in sediments increased greatly upon the addition of various carbon sources, indicating an energy limitation for nitrogenase (C
2
H
2
) activity. In situ determinations of dinitrogen fixation in sediments also indicated low rates and exhibited a similar response to glucose amendment. Litter from the green macroalga,
Ulva
spp., mangrove leaves, and sea grass also gave rise to significant rates of acetylene reduction.

Higher rates of nitrogenase activity (15 to 53 nmol of C
2
H
4
/g [wet weight] per h were associated with washed excised roots of three Florida mangrove species [
Rhizophora mangle
L.,
Avicennia germinans
(L) Stern, and
Laguncularia racemosa
Gaertn.] as well as with isolated root systems of intact plants (11 to 58 μg of N/g [dry weight] per h). Following a short lag period, root-associated activity was linear and did not exhibit a marked response to glucose amendment. It appears that dinitrogen-fixing bacteria in the mangrove rhizoplane are able to use root exudates and/or sloughed cell debris as energy sources for dinitrogen fixation.
Bacteria associated with the gastric epithelium of neonatal pigs
Authors: Fuller R , Barrow P A , Brooker B E
Published: January 2020

Light and electron microscopy showed lactobacilli and, to a lesser degree, streptococci to be closely associated with the squamous area of the pig stomach known as the pars esophagea. Several different types of extracellular layers were seen on bacteria attached to the epithelial surface. The total number of bacteria per square centimeter did not change with age up to 10 days, and there was no effect of weaning at 2 days. Lactobacillus fermentum, L. salivarius, and Streptococcus salivarius were isolated more frequently from sucking pigs than from those that were early weaned, whereas the reverse was true of L. acidophilus and S. bovis. All isolates recovered from washed macerated pars esophagea adhered to pig esophageal epithelial cells when tested in vitro.
Concentration of poliovirus from tap water onto membrane filters with aluminum chloride at ambient pH levels
Authors: Farrah S R , Goyal S M , Gerba C P , Wallis C , Melnick J L
Published: January 2020

A method is described for the concentration of an enterovirus from large volumes of tap water by addition of small amounts of aluminum chloride to enhance virus removal by membrane filters. Tap water treated with 2 X 10(-5) M aluminum chloride showed a slight decrease in pH (less than 0.5), a slight increase in turbidity, and enhanced removal of poliovirus by membrane filters. Virus was quantitatively recovered by treating the filters with a basic buffer, and this eluate was reconcentrated to a small volume by adsorption to aluminum hydroxide flocs. Using these procedures, virus from 1,000 liters of water was reduced to a final eluate of 20 to 80 ml with a mean recovery of 70%.
Production of trypsin inhibitor by a Cephalosporium sp
Authors: Tsuchiya K , Kimura T
Published: January 2020

Conditions for the production of the trypsin inhibitor from Cephalosporium sp. KM 388 were investigated. Polypeptone-meat extract-glucose medium supported excellent production of the trypsin inhibitor. In this medium, polypeptone and meat extract were utilized both as carbon and nitrogen sources and as limiting substrates for the cell growth. Glucose was consumed during the stationary growth phase and prevented the disappearance of inhibitor activity. Cephalosporium sp. KM 388 grew at a rate of a first-order reaction for the cell concentrations. Trypsin inhibitor production paralleled cell growth. At 27 degrees C the maximum specific rates of growth and inhibitor production were 0.14 h-1 and 2.1 U of inhibitor/h per mg of cell, respectively. The production rate and the maximum yield of the inhibitor were increased 1.5- and 1.2-fold, respectively, when the initial pH 6.3 was maintained throughout the fermentation.
Temperature-Sensitive Mutants of
Saccharomyces cerevisiae
Variable in the Methionine Content of Their Protein
Authors: Momose Haruo , Gregory Kenneth F.
Published: January 2020

Temperature-sensitive mutants were derived from
Saccharomyces cerevisiae
Y5α by ethyl methane sulfonate mutagenesis, in a search for mutants that would produce methionine-rich protein at the nonpermissive temperature. A total of 132 mutant strains were selected which showed adequate growth on minimal medium at 25°C but little or no growth on the same medium supplemented with a high concentration (2 mg/ml) of
l
-methionine at 37°C. Several of these mutants were found to increase the proportion of methionine in their protein to much higher levels than that of the wild-type parent after a temperature shift from 25 to 37°C. Two strains, 476 and 438, which were temperature sensitive only in the presence of methionine, produced cellular protein with methionine contents as high as 3.6 and 4.3%, respectively, when incubated in the presence of methionine. The former strain contained 2.5% methionine even when incubated at 37°C in the absence of methionine. Wild strain Y5α, on the other hand, had 1.75% methionine under all conditions tested. Most temperature-sensitive mutants isolated had the same methionine content as the wild strain. It is concluded that the proportion of a specific amino acid, such as methionine, in
S. cerevisiae
protein can be altered by culturing certain temperature-sensitive mutants at an elevated temperature.
Molds on vegetables at the time of harvest
Authors: Webb T A , Mundt J O
Published: January 2020

The mean numbers of colony-forming units of molds present on vegetables at the time of harvest were in the range of 4.2 X 10(3) to 6.7 X 10(3)/g for all vegetables except cucurbits and asparagus. The numbers were not influenced by cultivars within species, duration of the growing season, distant separation of the growing fields, or elevation above ground. Numbers increased with rainfall during either of 3 days before harvest and decreased when the mean daily temperature exceeded 24 degrees C. The most frequently isolated fungi were Aureobasidium pullulans, Fusarium species, Alternaria tenuis, Epicoccum nigrum, Mucor species, Chaetomium fimeti, Rhizopus nigricans, and Phoma species, in decreasing order. All other molds comprised less than 2% of the isolates. Aspergilli and penicillia occurred sporadically and in low numbers. Fusarium species were dominant on cucurbits.
Bacterial oxidation of polyethylene glycol
Authors: Kawai F , Kimura T , Fukaya M , Tani Y , Ogata K , Ueno T , Fukami H
Published: January 2020

The metabolism of polyethylene glycol (PEG) was investigated with a synergistic, mixed culture of Flavobacterium and Pseudomonas species, which are individually unable to utilize PEGs. The PEG dehydrogenase linked with 2,6-dichlorophenolindophenol was found in the particulate fraction of sonic extracts and catalyzed the formation of a 2,4-dinitrophenylhydrazine-positive compound, possibly an an aldehyde. The enzyme has a wide substrate specificity towards PEGs: from diethylene glycol to PEG 20,000 Km values for tetraethylene glycol (TEG), PEG 400, and PEG 6,000 were 11, 1.7, and 15 mM, respectively. The metabolic products formed from TEG by intact cells were isolated and identified by combined gas chromatography-mass spectrometry as triethylene glycol and TEG-monocarboxylic acid plus small amounts of TEG-dicarboxylic acid, diethylene glycol, and ethylene glycol. From these enzymatic and analytical data, the following metabolic pathway was proposed for PEG: HO(CH2CH2O)nCH2CH2OH leads to HO(CH2CH2O)nCH2CHO leads to HO(CH2CH2O)nCH2COOH leads to HO(CH2CH2O)n-1CH2CH2OH.
Biocidal Properties of Anti-Icing Additives for Aircraft Fuels
Authors: Neihof R. A. , Bailey C. A.
Published: January 2020

The biocidal and biostatic activities of seven glycol monoalkyl ether compounds were evaluated as part of an effort to find an improved anti-icing additive for jet aircraft fuel. Typical fuel contaminants,
Cladosporium resinae, Gliomastix
sp.,
Candida
sp.,
Pseudomonas aeruginosa
, and a mixed culture containing sulfate-reducing bacteria were used as assay organisms. Studies were carried out over 3 to 4 months in two-phase systems containing jet fuel and aqueous media. Diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, and 2-methoxyethanol were generally biocidal in aqueous concentrations of 10 to 17% for all organisms except
Gliomastix
, which required 25% or more. 2-Ethoxyethanol, 2-propoxyethanol, and 2-butoxyethanol were biocidal at progressively lower concentrations down to 1 to 2% for 2-butoxyethanol. The enhanced antimicrobial activity of these three compounds was attributed to cytoplasmic membrane damage because of the correlation between surface tension measurements and lytic activity with
P. aeruginosa
cells. The mechanism of action of the less active compounds appeared to be due to osmotic (dehydrating) effects. When all requirements are taken into account, diethylene glycol monomethyl ether appears to be the most promising replacement for the currently used additive, 2-methoxyethanol.
Hydrogen production by Anabaena cylindrica: effects of varying ammonium and ferric ions, pH, and light
Authors: Jeffries T W , Timourian H , Ward R L
Published: January 2020

Anabaena cylindrica sparged with argon gas produced H2 continuously for 30 days under limited light conditions (6.0 W/m2) and for 18 days under elevated light conditions (32 W/m2) in the absence of exogenous nitrogen. The efficiency of converting visible light energy (32 W/m2) into chemical energy that is trapped as H2 ranged between 0.35 and 0.85% (approximately 13 microliter of H2 per mg [drywt] per h). Ammonium additions (0.2 mM NH4+) at various times destabilized the system and eventually suppressed H2 production completely, as compared with the control. Cultures grown with 5.0 mg of Fe3+ per liter produced H2 at a rate about twice that of cultures with 0.5 mg of Fe3+ per liter. Cultures grown at pH 7.4 produced H2 at the same initial rates as cultures that were grown at pH 9.4; however, the latter cultures continued to produce H2 after CO2 deprivation.
Regiospecific synthesis of isoapocodeine from 10,11-dimethoxyaporphine by using Cunninghamella elegans
Authors: Smith R V , Davis P J
Published: January 2020

A preparative-scale regiospecific conversion of 10,11-dimethoxyaporphine to isoapocodeine was conducted with Cunninghamella elegans ATCC 9245. This biotransformation proceeded quantitatively in suspensions and was pH dependent. The influence of antioxidants on the conversion was studied. Attempts to preserve the activity of isolated C. elegans cells by a number of methods were unsuccessful.
Use of extractable adenosine triphosphate to estimate the viable cell mass in dental plaque samples obtained from monkeys
Authors: Robrish S A , Kemp C W , Bowen W H
Published: January 2020

The viable cell mass in plaque samples obtained from monkeys was estimated by determining the concentration of extractable adenosine triphosphate (ATP), and total cell mass was estimated by measuring the protein content. The results were expressed in terms of the specific ATP and protein contents of Streptococcus sanguis. The viable counts estimated by these techniques were comparable to or exceeded viable counts obtained by other investigators using conventional bacteriological methods.
Immobilization of Aspergillus beta-glucosidase on chitosan
Authors: Bissett F , Sternberg D
Published: January 2020

beta-Glucosidase of Aspergillus phoenicis QM 329 was immobilized on chitosan, using the bifunctional agent glutaraldehyde. The most active preparation based on the amount of support contained a 1:2.5 enzyme-to-chitosan ratio (wt/wt). However, the specific activity of the bound enzyme decreased from 10 to 1% with increasing enzyme-to-chitosan ratio. Compared with free beta-glucosidase, the immobilized enzyme exhibited: (i) a similar pH optimum but more activity at lower pH values; (ii) improved thermal stability; (iii) a similar response to inhibition by glucose; and (iv) mass transfer limitations as reflected by higher apparent Km and lower energy of activation.
Physiology of L-asparaginase synthesis in recombinants of Escherichia coli A-1
Authors: Barnes W R , Vela G R , Dorn G L
Published: January 2020

A mating between Escherichia coli 4318 (thi leu Las- Hfr) and E. coli A-1 (Met- Las+ F-) resulted in the formation of prototrophic recombinants having L-asparaginase activities at three distinct levels. The physiology of L-asparaginase synthesis in these recombinants is decribed. One class of recombinants produced significantly more L-asparaginase than E. coli A-1. L-Asparaginase synthesis in the recombinants was inhibited by the presence of dissolved oxygen in the medium and was transiently repressed by the presence of glucose in the same manner as that observed in the parental strains. L-Asparaginase activity was increased by the addition of oxalacetate as well as other members of the tricarboxylic acid cycle.
Plasmids, Lactic Acid Production, and
N
-Acetyl-
d
-Glucosamine Fermentation in
Lactobacillus helveticus
subsp.
jugurti
Authors: Smiley Martin B. , Fryder Vincent
Published: January 2020

Two lactobacillus strains,
Lactobacillus helveticus
subsp.
jugurti
S13-8 and
L. helveticus
subsp.
jugurti
S36-2, were examined for the presence of plasmids. Plasmids of 16.45, 13.03, and 11.83 kilobases (kb) were found in the first, low lactic acid-producing strain; their function is not presently known. A single plasmid species of 13.17 kb was found in the second, high lactic acid-producing strain. This plasmid was found to be associated with lactic acid production and
N
-acetyl-
d
-glucosamine fermentation.
Interactions between the diatom Thallasiosira pseudonanna and an associated pseudomonad in a mariculture system
Authors: Baker K H , Herson D S
Published: January 2020

The marine diatom Thallasiosira pseudonanna (3H) and several bacteria associated with it were isolated from batch cultures at the University of Delaware mariculture facility. The interaction between the algae and each of the bacteria was investigated. One of the isolates, T827/2B (Pseudomonas sp.), was incapable of surviving in f/2 culture medium unless the algae were present. When the algae and T827/2B were grown together in the f/2 medium, the bacterial growth was stimulated and the algal growth was inhibited. Bacterial filtrate had a similar effect on the algae, indicating that the bacterial effect is an indirect one most likely resulting from the excretion of a harmful compound into the medium. Preliminary characterization of the material excreted by the bacteria indicates that it s proteinaceous in nature. The interactions observed does not fit into any single category of interactions but can be explained as a combination of competition and indirect parasitism.
Chemiluminescent detection of bacteria: experimental and theoretical limits
Authors: Miller C A , Vogelhut P O
Published: January 2020

The limit of sensitivity of the chemiluminescent assay for detection of bacteria by hemeprotein catalysis of luminol oxidation was determined, both experimentally and theoretically, to be no lower than 10(5) to 10(6) viable bacterial per ml.
Effect of prior refrigeration on botulinal outgrowth in perishable canned cured meat when temperature abused
Authors: Tompkin R B , Christiansen L N , Shaparis A B
Published: January 2020

Perishable canned cured meat inoculated with Clostridium botulinum spores was placed at 4.4 or 10 degrees C after manufacture. Spore germination occurred at 10 degrees C. The germinated cell count remained stable over a period of 16 to 18 weeks. During that time period the inhibitory system and residual nitrite descreased. These factors combine to make perishable canned cured meats more prone to spoilage and potential hazard if they are temperature abused after a period of refrigerated storage.
Affinity chromatography purification of type A botulinum neurotoxin from crystalline toxic complex
Authors: Moberg L J , Sugiyama H
Published: January 2020

Type A botulinum neurotoxin was purified from toxic crystals by adsorption to p-aminophenyl-beta-D-thiogalactopyranoside coupled to CH-Sepharose 4B. At pH 6.3, the toxic complex was held by the binding between the ligand and the hemagglutinin of the complex; the toxin is eluted selectively by dissociating the complex with buffer-saline of pH 7.9. The single-step affinity chromatography recovered 50 to 60% of applied toxicity as preparations of greater than 99% purity.
Particle Nature, Yeast Strain, and Temperature Interactions on the Fermentation Rates of Grape Juice
Authors: Ough C. S. , Groat M. L.
Published: January 2020

Yeast strains of
Saccharomyces cerevisiae
behave differently to additions of finely sized particles added to clear grape juice. The type of material has a bearing on the effectiveness of increasing the rate of sugar conversion. In comparsion with a control sample, stirring and then adding grape solids back to the juice are most effective in maximizing sugar conversion, followed by addition of bentonite, talc, and diatomaceous earth. The improved fermentation efficiency is greater for all additions compared with unstirred controls. The formation of yeast flocs is enhanced by all additions. This fact can be used to partially explain the more effective fermentation rates. These additions appear to be equally effective over temperatures covering the normal fermentation temperature range.