bluuebunny/crossref_metadata_2025 huggingface dataset:
Methanogenic Bacteria from the Bondyuzhskoe Oil Field: General Characterization and Analysis of Stable-Carbon Isotopic Fractionation
Authors: Belyaev S. S. , Wolkin R. , Kenealy W. R. , DeNiro M. J. , Epstein S. , Zeikus J. G.
Published: January 2020

Selective enrichment culture techniques were employed to obtain mixed cultures of methanogenic rods and sarcina from surface flooding waters and deep subsurface (∼1650 m) oil-bearing sedimentary rocks and formation waters sampled from an old oil field in the U.S.S.R. previously reported to display active biological methanogenesis. The methanogens were selectively isolated as colonies on agar petri dishes that were incubated in a novel container. The general cellular and growth features of three
Methanobacterium
isolates were determined. These strains grew optimally at 37 to 45°C in anaerobic pressure tube cultures with a doubling time of 16 to 18 h on H
2
-CO
2
and proliferated as autotrophs. Acetate addition significantly enhanced the final cell yield. Growth of these strains was completely inhibited by either 0.6 g of sodium sulfide per liter or 31.0 of sodium chloride per liter, but growth was not inhibited by either 0.3 g of sodium sulfide per liter or 1.0 g of sodium sulfate per liter. One novel isolate,
Methanobacterium
sp. strain ivanov, was grown on H
2
-CO
2
, and the stable-carbon isotopic fractionations that occurred during synthesis of methane, cell carbon, and lipids were determined. The results of this study were used to examine the anomalous relationship between the isotopic and chemical compositions of natural gas occurring in the deep subsurface environment of the oil field.
Detection of Giardia lamblia by immunofluorescence
Authors: Riggs J L , Dupuis K W , Nakamura K , Spath D P
Published: January 2020

High-titer immune sera to cysts of Giardia lamblia, produced in guinea pigs, were labeled with fluorescein isothiocyanate. The resulting conjugates were used to detect G. lamblia in stool specimens by fluorescence microscopy. The sera also reacted with cysts of Chilomastix mesnili, but the two organisms could be differentiated by their size.
Free-Living
Rhizobium
Strain Able To Grow on N
2
as the Sole Nitrogen Source
Authors: Dreyfus B. L. , Elmerich C. , Dommergues Y. R.
Published: January 2020

A
Rhizobium
strain isolated from stem nodules of the legume
Sesbania rostrata
was shown to grow on atmospheric nitrogen (N
2
) as the sole nitrogen source. Non-N
2
-fixing mutants isolated directly on agar plates formed nodules that did not fix N
2
when inoculated into the host plant.
Influence of yield on in vitro accumulation of aflatoxins in pecan (Carya illinoensis (Wang.) K. Koch) nutmeats
Authors: McMeans J L
Published: January 2020

Pecans were harvested from trees (Carya illinoensis (Wang.) K. Koch) in November of 1977 through 1979. Kernel meals from high-, medium-, and low-yielding trees were inoculated with a spore suspension of Aspergillus parasiticus and incubated for 7 days at 25 degrees C. Significant differences in aflatoxin accumulation were found among the three substrates, with a direct correlation between high aflatoxin concentration and tree yield.
Nutritional Interdependence Among Rumen Bacteria During Cellulose Digestion In Vitro
Authors: Miura Hideki , Horiguchi Masaaki , Ogimoto Keiji , Matsumoto Tatsuro
Published: January 2020

A study has been made of the promoting effect of starch on cellulose digestion by mixed rumen bacteria in a cellulose-urea medium. Starch supplementation of the medium promoted the growth of bacteria that required neither amino acids (AA) nor branched-chain fatty acids (BrFA). The growth of these bacteria was followed by the growth of AA-dependent bacteria, AA- or BrFA-dependent bacteria, BrFA-producing bacteria, and finally, BrFA-dependent cellulolytic bacteria. Population changes of these bacterial groups corresponded with a cross-feeding of AA and BrFA and the overall disappearance of cellulose. The data suggest that the nutritional interdependence among rumen bacteria affects the rate of cellulose digestion.
Detection of Industrial Pollutants and Toxic Chemical Wastes in Sewage Treatment Plant Influents by Use of a Biological Monitor
Authors: McElroy Lloyd J.
Published: January 2020

Heterogeneous mixtures of toxic chemical wastes affecting the normal operations of a sewage treatment facility employing anaerobic digestion were detected by dark-field observation of uncoordinate flagellar orientation patterns displayed by cells of
Spirillum volutans
. These results were compared with plant parameters determined by gas production, volatile fatty acids, and alkalinity measurements.
Bacterial Populations Associated with Different Regions of the Human Colon Wall
Authors: Croucher Susan C. , Houston Annette P. , Bayliss Catherine E. , Turner R. J.
Published: January 2020

The microorganisms associated with the undiseased human colon wall were examined in material obtained from four sudden-death victims. In traffic accident subjects (aged 45 and 16 years) the anaerobe-aerobe ratio was about 10
4
:1 in all areas of the colon examined, whereas in acute heart failure subjects (aged 74 and 46 years) the ratio was as low as 1.2:1. The flora of each individual was distinct and complex. Although the predominant anaerobes isolated were
Bacteroides
and
Fusobacterium
spp., which composed over 50% of the flora in some samples, the species isolated (indicated by morphology and glucose fermentation products) varied between individuals. Other major types observed were gram-positive nonsporing rods, including
Bifidobacterium
spp., and anaerobic cocci (between 8 and 20% of isolates). Clostridia were only isolated in significant numbers from one individual. Scanning electron microscopy showed that most of the organisms were present below the top surface of the mucin layer overlying the mucosa. The use of several different preparative procedures for microscopy showed a complex microbial structure within the mucus, but major variations in the bacterial populations in different areas of the colon were not found. Spiral-shaped organisms up to 60 μm long in the form of double helices were found in two subjects by scanning electron microscopy but were not isolated during the parallel bacteriological investigation. The differences between this and previous studies are discussed in relation to experimental procedures and also in contrast to results with animals that showed a particularly specialized flora associated with the colon wall.
Chlorine-induced damage to surface adhesions during sublethal injury of enterotoxigenic Escherichia coli
Authors: Walsh S M , Bissonnette G K
Published: January 2020

A comparison of the adhesive ability of noninjured and chlorine-injured enterotoxigenic Escherichia coli was made by in vitro attachment to human peripheral leukocytes. Chlorination selected for noninjured cells with greater capabilities for colonizing the small intestine. Injured populations exhibited reduced association with leukocytes. Maximum reduction was seen in populations with greater than 80% injury. These cells demonstrated less adhesive ability than nonpiliated populations. Electron micrographs suggested that reduced adhesive ability was due to the loss of surface structures as a consequence of sublethal chlorination. The data imply a reduced ability among chlorine-injured pathogens to colonize the small intestine and initiate disease.
Microbial fouling of reverse-osmosis membranes used in advanced wastewater treatment technology: chemical, bacteriological, and ultrastructural analyses
Authors: Ridgway H F , Kelly A , Justice C , Olson B H
Published: January 2020

Biofouling of reverse-osmosis membranes was investigated at an advanced wastewater treatment facility. Cellulose diacetate membranes operated for approximately 4,000 h became uniformly coated with a mucilaginous fouling layer. The fouling material was approximately 93% water by weight, and nearly 90% of the dehydrated residue was organic in composition. Calcium, phosphorous, sulfur, and chlorine were the major inorganic constituents detected. Protein and carbohydrate represented as much as 30 and 17%, respectively, of the dry weight of the biofilm. Bacteriological plate counts indicated up to 5.6 X 10(6) CFU/cm2 of membrane surface. Accumulation of [3H]glucose in the biofilm and measurement of ATP indicated that the fouling bacteria were metabolically active in situ. The genus Acinetobacter and the Flavobacterium-Moraxella group were the major generic groups associated with the feedwater surface of the membrane, whereas species of the generic groups Acinetobacter, Pseudomonas-Alcaligenes, and Bacillus-Lactobacillus predominated on the permeate water surface. Electron microscopy revealed that the biofilm on the feedwater surface of the membrane was 10 to 20 microns thick and was composed of several layers of compacted bacterial cells, many of which were partially or completely autolyzed. The bacteria were firmly attached to the membrane surface by an extensive network of extracellular polymeric fibrils. Polyester (Texlon) support fibers located on the permeate surface of the reverse osmosis membranes were sparsely colonized, suggesting bacterial regrowth in the product water collection system.
Improved facility and sensitivity in the use of guinea pigs for the isolation of Legionella pneumophila from cooling tower water
Authors: Leinbach E D , Winkler H H , Wood D O , Coggin J H
Published: January 2020

The established criteria for the determination of the optimum time for the sacrifice of guinea pigs inoculated with samples of cooling tower water were found to be inadequate for the detection of low levels of Legionella pneumophila. By ignoring the requirement for fever and by sequentially sacrificing the infected guinea pigs on days 3 through 5 postinoculation, we simplified the procedure, and the sensitivity of detection was improved a great deal.
Comparison of Verification Procedures for the Membrane Filter Total Coliform Technique
Authors: LeChevallier Mark W. , Cameron Susan C. , McFeters Gordon A.
Published: January 2020

Verification of membrane filter total coliform colonies from drinking water was increased 87% by testing for the presence of β-galactosidase and cytochrome oxidase, compared with verification by determination of gas production in lauryl tryptose broth. Over 90% of the coliforms verified by testing for β-galactosidase and cytochrome oxidase were representative of the typical coliform genera.
Modified method for production and purification of Staphylococcus aureus enterotoxin B
Authors: Melconian A K , Flandrois J P , Fleurette J
Published: January 2020

A medium containing 4% bio-trypcase and 1% yeast extract was used for the production of Staphylococcus aureus enterotoxin B. The yield obtained was estimated at 200 micrograms of enterotoxin per ml of S. aureus S-6 culture supernatant. The purification method involves chromatography on Biorex 70 resin, isoelectric focusing, and gel filtration on Sephadex G-100. The purified enterotoxin (isoionic point, pH 8.55) was shown to be homogenous protein with a molecular weight of 29,000 when tested by gel electrophoresis.
Production of Epoxides from α,β-Halohydrins by
Flavobacterium
sp
Authors: Geigert John , Neidleman Saul L. , Liu Te-Ning E. , DeWitt Susanne K. , Panschar Barbara M. , Dalietos Demetrios J. , Siegel Eric R.
Published: January 2020

The relative activity of
Flavobacterium
whole cells on the enzymatic synthesis of epoxides from α,β-chlorohydrins, -bromohydrins, and -iodohydrins is described.
Monitoring Microbial Numbers in Food by Density Centrifugation
Authors: Basel Richard M. , Richter Edward R. , Banwart George J.
Published: January 2020

Some foods contain low numbers of microbes that may be difficult to enumerate by the plate count method due to small food particles that interfere with the counting of colonies. Ludox colloidal silicon was coated with reducing agents to produce a nontoxic density material. Food homogenates were applied to a layered 10 and 80% mixture of modified Ludox and centrifuged at low speed. The top and bottom of the tube contained the food material, and the Ludox-containing portion was evaluated by conventional pour plate techniques. Plate counts of the Ludox mixture agreed with plate counts of the food homogenate alone. The absence of small food particles from pour plates resulted in a plate that was more easily read than pour plates of the homogenate alone. Modified Ludox was evaluated for its effect on bacteria at 4°C during a 24-h incubation period. No inhibition was observed. This method is applicable to food products, such as doughnuts, spices, tomato products, and meat, in which small food particles often interfere with routine plate counts or low dilution may inhibit colony formation. Inhibitory substances can be removed from spices, resulting in higher counts. Ludox is more economical than similar products, such as Percoll. Modified Ludox is easily rendered nontoxic by the addition of common laboratory reagents. In addition, the mixture is compatible with microbiological media.
In vitro exposure of adenovirus types 5 and 7 in oropharyngeal secretions to cigarette smoke
Authors: Bardell D
Published: January 2020

Adenovirus types 5 and 7 were suspended in clarified oropharyngeal secretions. After 1 ml of suspension was dispersed in a thin layer over a 25-cm2 surface in a flask, the suspension was exposed at 37 degrees C to eight 25-ml puffs of smoke from one cigarette. A mechanical smoking apparatus was used. Nonfilter cigarettes used had 23 mg of tar and 1.4 mg of nicotine, and filter cigarettes used had 19 mg of tar and 1.2 mg of nicotine. Smoke was flushed from the flask with normal filtered air. At 0, 0.25, and 1 h after exposure to smoke, untreated and smoke-treated viruses were titrated with monolayer cultures of human epithelioid (HEp-2) cells. Normal air was in contact with the suspensions between puffs and between smoke treatments and virus titrations. Smoke from filter or nonfilter cigarettes had no effect on the infectivity and replication of adenovirus types 5 and 7. Smoke from four cigarettes administered over a 4-h period caused a 2- to 3-log10 drop in the titers of both viruses. Smoke from four cigarettes was also highly toxic to HEp-2 host cells of the viruses.
Bacterial Methylation of Chlorinated Phenols and Guaiacols: Formation of Veratroles from Guaiacols and High-Molecular-Weight Chlorinated Lignin
Authors: Neilson Alasdair H. , Allard Ann-Sofie , Hynning Per-Åke , Remberger Mikael , Landner Lars
Published: January 2020

Two strains of bacteria, provisionally assigned to the genus
Arthrobacter
, were shown to metabolize mono-, di-, tri-, and tetrachloroguaiacols and pentachlorophenol to the corresponding
O
-methyl compounds. Hydroxylated intermediates were formed only transiently, except for the synthesis by one strain of 3,4,5-trichlorosyringol from 3,4,5-trichloroguaiacol. Two isomeric trichloroveratroles and tetrachloroveratrole were formed by three of the strains from a high-molecular-weight chlorinated lignin isolated from kraft pulp mill bleach plant. The concentrations of methylated metabolites varied widely and did not appear to be correlated with degradation. The possible environmental consequences resulting from synthesis of these highly lipophilic substances are discussed briefly.
Amino Acid Assimilation and Electron Transport System Activity in Attached and Free-Living Marine Bacteria
Authors: Bright J. J. , Fletcher Madilyn
Published: January 2020

Amino acid assimilation and electron transport system activity of a marine
Pseudomonas
sp. was evaluated to determine whether the activity of bacteria attached to solid surfaces differed from that of free-living bacteria or bacteria which had been attached but subsequently desorbed from the substratum (detached bacteria). Bacteria were allowed to attach to glass and to a range of plastic surfaces (Thermanox, polyvinylidene fluoride, polyethylene, polytetrafluoroethylene). Microautoradiography and staining with a tetrazolium salt to demonstrate electron transport system activity were used to compare the activity of these organisms with that of free-living or detached cells. The water-wettability of the surfaces was evaluated by measuring the advancing contact angle (θ
A
) of water on each surface, to determine whether there was a relationship between activity and substratum hydrophilicity. There was an increase in the proportion of leucine-assimilating attached bacteria and in the proportion of attached cells demonstrating electron transport system activity with an increase in substratum θ
A
, but the relationship between activity of attached and free-living cells depended on the substratum. Activity appeared to promote firm attachment, and detached bacteria assimilated fewer amino acids than did attached cells. There was no general effect of surfaces on attached bacterial activity, and attached cells may be more, or less, active than free-living cells, depending on the amino acid, its concentration, and substratum properties.
Concentration of Simian Rotavirus SA-11 from Tap Water by Membrane Filtratiòn and Organic Flocculation
Authors: Guttman-Bass Naomi , Armon Robert
Published: January 2020

Simian rotavirus SA-11 was concentrated from tap water by adsorption to and elution from microporous filters, followed by organic flocculation. Two types of filters were compared for their ability to concentrate the virus. Both Zeta Plus 60S and Cox AA type M-780 filters were efficient for virus adsorption, but the efficiency of virus elution was higher with Zeta Plus than with Cox filters. Optimum conditions for virus recovery from Zeta Plus filters included an input water pH of 6.5 to 7.5 and the use of 3% beef extract (pH 9.0) for elution. Under these conditions, an average of 62 to 100% of the virus was recovered in the concentrate. Organic flocculation was used as a second-step concentration method, with average recoveries of 47 to 69%. When the two methods were used to concentrate small numbers (7 to 75 PFU/liter) of input rotavirus, an average of 75 ± 40% recovery was achieved. With large volumes of input water, however, recovery was reduced to 16 ± 7%.
Hydrogen Recycling by
Rhizobium leguminosarum
Isolates and Growth and Nitrogen Contents of Pea Plants (
Pisum sativum
L.)
Authors: Nelson Louise M.
Published: January 2020

The ability to recycle H
2
evolved by nitrogenase is thought to be of importance in increasing the efficiency of N
2
fixation and to be a factor in increasing plant yield in symbiotic systems. To determine whether this ability is a significant factor in the
Rhizobium leguminosarum-Pisum sativum
L. system, plants were inoculated with
R. leguminosarum
isolates which differed in their ability to oxidize H
2
and in their relative efficiency of N
2
fixation. These plants were grown at three levels of irradiance and harvested after 3, 4, and 5 weeks of growth for determination of C
2
H
2
reduction, H
2
evolution and uptake, plant dry weight, and N content. Plants inoculated with uptake hydrogenase-positive (Hup
+
) isolates did not exhibit higher dry weight or N content than those inoculated with Hup
−
isolates under any of the growth conditions studied. The efficiency of the nitrogenase system of Hup
−
isolates increased at a low irradiance, a factor which may allow them to compete successfully with Hup
+
isolates. In some Hup
+
R. leguminosarum
isolates, H
2
oxidation is coupled to ATP formation, whereas in others, it is not. There were no differences in plant dry weight and N content in plants inoculated with the two types and grown for 5 weeks at three irradiance levels. The addition of H
2
to Hup
+
nodules whose supply of photosynthate had been removed by stem excision did not increase C
2
H
2
reduction in either coupled or uncoupled types.
Light as an Energy Source in Continuous Cultures of Bacteriorhodopsin-Containing Halobacteria
Authors: Rodriguez-Valera F. , Nieto J. J. , Ruiz-Berraquero F.
Published: January 2020

The role of light as an energy source for slightly aereated cultures of halobacteria was studied, using continuous cultures with low nutrient concentrations and a low oxygen supply. A series of experiments were carried out with non-illuminated and differently illuminated cultures and with different oxygen transfer rates. Under low oxygen availability, light proved to be a decisively important energy source that allowed the populations to reach higher growth rates and much higher population densities. Oxygen influenced the growth over only a minimal level, below which neither the illuminated nor the dark cultures were affected by the oxygen transfer rate. From these results, it appears that the bacteriorhodopsin-mediated energy supply could have a very important role for the ecology of halobacteria in their microaerophilic habitats. In the illuminated cultures, cells that originated purple colonies on plates appeared. These cells, which could be bacteriorhodopsin-constitutive mutants, are now being studied.
Production and Characteristics of Raw Starch-Digesting Glucoamylase O from a Protease-Negative, Glycosidase-Negative
Aspergillus awamori
var.
kawachi
Mutant
Authors: Flor Perfecto Q. , Hayashida Shinsaku
Published: January 2020

Production of a raw starch-digesting glucoamylase O (GA O) by protease-negative, glycosidase-negative mutant strain HF-15 of
Aspergillus awamori
var.
kawachi
was undertaken under submerged culture conditions. The purified GA O was electrophoretically homogeneous and similar to the parent glucoamylase I (GA I) in the hydrolysis curves toward gelatinized potato starch, raw starch, and glycogen and in its thermostability and pH stability, but it was different in molecular weight and carbohydrate content (250,000 and 24.3% for GA O, 90,000 and ca. 7% for GA I, respectively). The chitin-bound GA O hydrolyzed raw starch but the chitin-bound GA I failed to digest raw starch because chitin was adsorbed at the raw starch affinity site of the GA I molecule. The removal of the raw starch affinity site of GA O with subtilisin led to the formation of a modified GA O (molecular weight, 170,000), which hydrolyzed glycogen 100%, similar to GA O and GA I, and was adsorbed onto chitin and fungal cell wall but not onto raw starch, Avicel, or chitosan. The modified GA I (molecular weight, 83,000) derived by treatment with substilisin hydrolyzed glycogen up to only 80% and failed to be adsorbed onto any of the above polysaccharides. The
N
-bromosuccinimide-oxidized GA O lost its activity toward gelatinized and raw starches, but the abilities to be adsorbed onto raw starch and chitin were preserved. It was thus suggested that both the raw starch affinity site essential for raw starch digestion and the chitin-binding site specific for the binding with chitin in the cell wall could be different from the active site, located in the three respective positions in the GA O molecule.
Natural atmospheric microbial conditions in a typical suburban area
Authors: Jones B L , Cookson J T
Published: January 2020

Ambient outdoor concentrations and size distributions of airborne microbial particles were measured approximately weekly for 2 years in a Washington, D.C., suburban area. The study objective was to characterize microbial air quality in the vicinity of a proposed sewage sludge composting facility. During the study, 379 samples were taken at 17 stations, using Andersen microbial samplers. Concentration ranges (in viable particles per cubic meter) were as follows: airborne mesophilic fungi, 0 to 7,220 with a geometric mean of 273; thermophilic fungi, 0 to 193 with a median of 2.1; Aspergillus fumigatus, 0 to 71 with a median of 1.0; aerobic bacteria, 4.2 to 1,640 with a geometric mean of 79; and fecal streptococci, 0 to 5.7 with a median of 0. No fecal coliforms were recovered. The potentially respirable fraction (less than 8 microns) averaged 34% for total bacteria, 56% for mesophilic fungi, 91% for thermophilic fungi, and 95% for A. fumigatus. The specific sampling location was not a major factor affecting microbial particle concentrations or size distributions. Conversely, the time of year was an important determinant of viable particle concentrations for all groups of microorganisms studied. The highest concentrations were observed in summer and fall, with significantly lower levels detected in winter. In general, the microbial data did not correlate with other variables, including weather conditions, measured in this study.
Lactoferrin and transferrin fragments react with nitrite to form an inhibitor of Bacillus cereus spore outgrowth
Authors: Custer M C , Hansen J N
Published: January 2020

Tryptone is a pancreatic digest of casein which contains a heterogeneous mixture of substances that react with nitrite when heated in the presence of sodium thioglycolate to form a bacteriostatic agent which inhibits outgrowth of Bacillus cereus T spores. The substances which are precursors to the bacteriostatic agent can be fractionated on the basis of molecular size and charge and have properties which indicate that they are fragments of lactoferrin, an iron-binding glycoprotein. The bacteriostatic agent could also be formed directly from purified lactoferrin after it had been subjected to proteolysis. Transferrin, an analogous iron-binding protein found in animal serum, also showed these same properties. This system may be a useful model for studies of the mechanism and site of nitrite bacteriostatic action.
Population Ecology of Nitrifiers in a Stream Receiving Geothermal Inputs of Ammonium
Authors: Cooper A. Bryce
Published: January 2020

The distribution, activity, and generic diversity of nitrifying bacteria in a stream receiving geothermal inputs of ammonium were studied. The high estimated rates of benthic nitrate flux (33 to 75 mg of N · m
−2
· h
−1
) were a result of the activity of nitrifiers located in the sediment. Nitrifying potentials and ammonium oxidizer most probable numbers in the sediments were at least one order of magnitude higher than those in the waters. Nitrifiers in the oxygenated surface (0 to 2 cm) sediments were limited by suboptimal temperature, pH, and substrate level. Nitrifiers in deep (nonsurface) oxygenated sediments did not contribute significantly to the changes measured in the levels of inorganic nitrogen species in the overlying waters and presumably derived their ammonium supply from ammonification within the sediment. Ammonium-oxidizing isolates obtained by a most-probable number nonenrichment procedure were species of either
Nitrosospira
or
Nitrosomonas
, whereas all those obtained by an enrichment procedure (i.e., selective culture) were
Nitrosomonas
spp. The efficiency of the most-probable-number method for enumerating ammonium oxidizers was calculated to be between 0.05 and 2.0%, suggesting that measurements of nitrifying potentials provide a better estimate of nitrifying populations.
Inhibition of Chemoautotrophic Nitrification by Sodium Chlorate and Sodium Chlorite: a Reexamination
Authors: Hynes Russell K. , Knowles Roger
Published: January 2020

The oxidation of NH
4
+
by
Nitrosomonas europaea
was insensitive to 10 mM NaClO
3
(sodium chlorate) but was strongly inhibited by NaClO
2
(sodium chlorite;

K
i

, 2 μM). The oxidation of NO
2
−
by
Nitrobacter winogradskyi
was inhibited by both ClO
3
−
and ClO
2
−
(

K
i

for ClO
2
−
, 100 μM).
N. winogradskyi
reduced ClO
3
−
to ClO
2
−
under both aerobic and anaerobic conditions, and as much as 0.25 mM ClO
2
−
was detected in the culture filtrate. In mixed
N. europaea-N. winogradskyi
cell suspensions, the oxidation of both NH
4
+
and NO
2
−
was inhibited in the presence of 10 mM ClO
3
−
after a 2-h lag period, despite the fact that, under these conditions, ClO
2
−
was not detected in the filtrate. The data are consistent with the hypothesis that, in mixed culture, NH
4
+
oxidation is inhibited by ClO
2
−
produced by reduction of ClO
3
−
by the NO
2
−
oxidizer. The use of ClO
3
−
inhibition of NO
2
−
oxidation in assays of nitrification by mixed populations necessitates cautious interpretation unless it can be shown that the oxidation of NH
4
+
is not affected.
Formation of (4R)- and (4S)-4-hydroxyochratoxin A and 10-hydroxyochratoxin A from Ochratoxin A by rabbit liver microsomes
Authors: Størmer F C , Støren O , Hansen C E , Pedersen J I , Aasen A J
Published: January 2020

Three metabolites were formed from ochratoxin A in the presence of rabbit liver microsomal fractions and NADPH. They were isolated by extraction, thin-layer chromatography, and high-pressure liquid chromatography. Two of them were identified as (4R)- and (4S)-4-hydroxyochratoxin A. It is suggested on the basis of mass and nuclear magnetic resonance spectroscopy that the third metabolite is 10-hydroxyochratoxin A. The formation of the metabolites was inhibited by carbon monoxide and metyrapone and was stimulated when microsomes from phenobarbital-treated animals were used. The results suggest that cytochrome P-450 catalyzes the formation of these metabolites.
Effects of disinfectants on Campylobacter jejuni
Authors: Wang W L , Powers B W , Leuchtefeld N W , Blaser M J
Published: January 2020

Because of the increasing recognition that Campylobacter jejuni is an important enteric pathogen of humans, we studied the effects of widely used disinfectants on the viability of this organism. At an inoculum size of 10(3) to 10(4) CFU/ml, 1.25 mg of hypochlorite per liter killed three strains within 1 min. At an inoculum size of 10(6) to 10(7) CFU/ml, 5 mg of hypochlorite per liter killed three strains within 15 min. Killing of similar concentrations of C. jejuni and Escherichia coli by hypochlorite was approximately the same. At the high inoculum, 0.15% phenolic compound, 10 mg of iodophor per liter, 1:50,000 quaternary ammonium compound, 70% ethyl alcohol, and 0.125% glutaraldehyde killed all three strains within 1 min. These studies demonstrate that, under the conditions we tested (pH 7.0; 24 to 26 degrees C), the recommended standard concentrations of disinfecting agents are adequate to destroy C. jejuni.
Role of Light Intensity and Temperature in the Regulation of Hydrogen Photoproduction by the Marine Cyanobacterium
Oscillatoria
sp. Strain Miami BG7
Authors: Phlips E. J. , Mitsui A.
Published: January 2020

The effects of several key environmental factors on the development and control of hydrogen production in the marine blue-green alga (cyanobacterium)
Oscillatoria
sp. strain Miami BG7 were studied in relation to the potential application of this strain to a bio-solar energy technology. The production of cellular biomass capable of evolving hydrogen gas was strongly affected by light intensity, temperature, and the input of ammonia as a nutrient. Depletion of combined nitrogen from the growth media was a prerequisite for the initiation of hydrogen production. Maximum hydrogen-producing capability coincided with the end of the linear phase of growth. Hydrogen production exhibited considerable flexibility to environmental extremes. The rate of production saturated at low light intensities (i.e., 15 to 30 μEinsteins/m
2
per s), and no photoinhibition was observed at high light intensity (i.e., 1,000 μEinsteins/m
2
per s). The upper temperature limit for production was 46°C. Above the light compensation point for O
2
evolution H
2
production was inhibited. However, this problem was alleviated by two related phenomena. (i) The capacity of cells to evolve oxygen deteriorated with increasing culture age and nitrogen depletion, and (ii) the ability of these cells to produce oxygen in closed anaerobic hydrogen production systems was temporally limited.
Safety evaluation of nuclear polyhedrosis virus replication in pigs
Authors: Döller G , Gröner A , Straub O C
Published: January 2020

To evaluate the hygienic risk involved in using baculoviruses for insect pest control, safety studies are required. Pigs were chosen as representative test animals of commercial and agricultural importance. The tests were aimed at detecting virus propagation, immune reactions, and signs of acute infection (changes in body temperature and hematology profile, swelling of lymph nodes). Four of five animals inoculated with nuclear polyhedrosis virus showed a slight temperature rise at day 2 postinfection. After day 4 postinfection, no differences between infected animals and controls were observed. In the bioassay, virus activity could be recovered from fecal samples; however, no activity was found in organ extracts. The data did not indicate hygienic risks involved in the application of nuclear polyhedrosis virus, especially that from Mamestra brassicae, in biological pest control.
Transformations of halogenated organic compounds under denitrification conditions
Authors: Bouwer E J , McCarty P L
Published: January 2020

Trihalomethanes, carbon tetrachloride, 1,1,1-trichloroethane, 1,2-dibromoethane, chlorinated benzenes, ethylbenzene, and naphthalene at concentrations commonly found in surface and groundwater were incubated under anoxic conditions to study their transformability in the presence of denitrifying bacteria. None of the aromatic compounds showed significant utilization relative to sterile controls at initial concentrations from 41 to 114 micrograms/liter after 11 weeks of incubation. Of the halogenated aliphatic compounds studied, transformations of carbon tetrachloride and brominated trihalomethanes were observed after 8 weeks in batch denitrification cultures. Carbon from the decomposition of carbon tetrachloride was both assimilated into cell material and mineralized to carbon dioxide. How this was possible remains unexplained, since carbon tetrachloride is transformed to CO2 by hydrolysis and not by oxidation-reduction. Chloroform was detected in bacterial cultures with carbon tetrachloride initially present, indicating that reductive dechlorination had occurred in addition to hydrolysis. The data suggest that transformations of certain halogenated aliphatic compounds are likely to occur under denitrification conditions in the environment.
Characteristics of Escherichia coli grown in bay water as compared with rich medium
Authors: Chai T J
Published: January 2020

Membrane-filtered bay water can support a certain degree of growth of Escherichia coli organisms isolated from the bay water or from sewage. The effect of the growth medium (bay water versus rich medium) on sensitivities to antimicrobial agents and cell envelope proteins was studied in many of these strains. Bay water-grown cells were less sensitive to bacteriophages and colicins, but were more sensitive to heavy metals and detergents as compared with rich-medium-grown cells. These results indicated that the cell envelope composition of the bay water-grown cells could be modified, resulting in altered susceptibility to various antimicrobial agents. An analysis of cell envelope proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that cells from rich-medium-grown cultures contained two or three major outer membrane proteins, whereas in bay water-grown cells, the OmpF protein was greatly reduced.
Direct Measurements of Steady-State Kinetics of Cyanobacterial N
2
Uptake by Membrane-Leak Mass Spectrometry and Comparisons Between Nitrogen Fixation and Acetylene Reduction
Authors: Jensen Bent Borg , Cox Raymond P.
Published: January 2020

A mass spectrometer with a membrane-covered inlet was used to measure nitrogen fixation by following changes in the concentration of dissolved N
2
in a stirred suspension of the cyanobacterium
Anabaena variabilis
in an open system. The results showed a good fit to Michaelis-Menten kinetics with a
K

m

for N
2
of 65 μM at 35°C, corresponding to 0.121 atmosphere of N
2
. Corresponding values for the
K

m

for acetylene reduction were 385 μM (0.011 atmosphere at 35°C). Comparison of the values of
V
max
for N
2
uptake with those for the acetylene reduction assay under similar conditions gave an average value of 3.8 for the conversion factor between N
2
and C
2
H
2
reduction. Reduction of protons to hydrogen was completely inhibited at sufficiently high concentrations of C
2
H
2
, but even at saturating N
2
concentrations, 1 mol of H
2
was produced for every mole of N
2
reduced. This explains the finding that the observed C
2
H
2
/N
2
ratio is higher than the value of 3 expected from the requirement for two electrons for acetylene reduction and six for nitrogen reduction. The results correlate well with a mechanism for N
2
reduction involving the equation: N
2
+ 8H
+
+ 8e
−
→ 2NH
3
+ H
2
which gives a conversion factor between C
2
H
2
and N
2
of 4. It is proposed that, in general, 4 is a more appropriate value than 3 for the conversion factor.
Use of magnesium to increase sensitivity of Limulus amoebocyte lysate for detection of endotoxin
Authors: Tsuji K , Steindler K A
Published: January 2020

Increased sensitivity of the Limulus amoebocyte lysate (LAL) assay for the detection of endotoxin was attained by the reconstitution of commercially available LAL reagent with a magnesium-containing solution. As little as 2 to 6 pg (0.002 to 0.006 ng) of Escherichia coli O127:B8 endotoxin per ml was detected, an increase in sensitivity of 10 to 30 times. The optimum magnesium concentration range for the LAL reagent used and the optimum pH range were approximately 50 to 65 mM and pH 6.0 to 8.0, respectively. Reconstitution of five commercially available brands of LAL with a solution containing magnesium resulted in greater assay sensitivity than the identical LAL reconstituted with pyrogen-free water. Use of LAL reconstituted with a solution containing magnesium is crucial for the assay of some parenteral products, wherein increased sensitivity is essential to meet the requirement for the maximum valid dilution criteria. The mode of action of magnesium for enhanced sensitivity of LAL has been postulated.
Proposed mechanism for sensitization by hypochlorite treatment of Clostridium botulinum spores
Authors: Foegeding P M , Busta F F
Published: January 2020

Hypochlorite-treated Clostridium botulinum 12885A spores, but not buffer-treated spores, could be germinated with lysozyme, indicating that their coats are made permeable to lysozyme by hypochlorite treatment so that the cortex is accessible. Hypochlorite-treated spores and spores extracted with 8 M urea-2-mercaptoethanol (pH 3.0) were sensitive to certain components of recovery media, but spores sensitized to lysozyme by other treatments were not. These data indicate that hypochlorite does more than increase coat permeability to lysozyme. Scanning electron microscopy revealed a more open-appearing surface of hypochlorite-treated spores, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that a greater amount of protein was removed from hypochlorite-treated and other lysozyme-sensitized spores than from buffer-treated spores. The data suggest that spore coat proteins may be removed by hypochlorite treatment, and this may be responsible for the sensitivity of spores and for their observed ability to germinate in lysozyme.
Pathways of Propionate Degradation by Enriched Methanogenic Cultures
Authors: Koch Markus , Dolfing Jan , Wuhrmann Karl , Zehnder Alexander J. B.
Published: January 2020

A mixed methanogenic culture was highly enriched in a growth medium containing propionate as the sole organic carbon and energy source. With this culture, the pathways of propionate degradation were studied by use of
14
C-radiotracers. Propionate was first metabolized to acetate, carbon dioxide, and hydrogen by nonmethanogenic organisms. Formate was not excreted. The carbon dioxide originated exclusively from the carboxyl group of propionate, whereas both [2-
14
C]- and [3-
14
C]propionate lead to the production of radioactive acetate. The methyl and carboxyl groups of the acetate produced were equally labeled, regardless of whether [2-
14
C]- or [3-
14
C]propionate was used. These observations suggest that in the culture, propionate was degraded through a randomizing pathway.
Selection of Wine Yeasts for Growth and Fermentation in the Presence of Ethanol and Sucrose
Authors: Benítez Tahía , del Castillo Lucas , Aguilera Andrés , Conde Jaime , Cerdáolmedo E.
Published: January 2020

To optimize the conversion of carbohydrates to ethanol, strains of several
Saccharomyces
species were examined for the ability to grow and ferment in a range of sucrose and ethanol concentrations. A total of 632 wine yeasts, most of them isolated from wineries in Andalusia and Extremadura, southwestern Spain, were subjected to screening and selection. Growth and fermentative capacity in different ethanol and sucrose concentrations varied from one strain to another. There was no correlation between growth and fermentative capacity. The best 35 strains grew in 15% ethanol and fermented in 18% ethanol. Ethanol accumulated, although at a reduced rate, after the cells stopped growing. Most yeast strains were highly fermentative in 50% sucrose. Some of them effectively utilized the carbohydrates of the culture, yielding final ethanol concentrations of > 14%. Of the 35 selected strains, 16 were promising for genetic analysis and breeding because of their capacity to sporulate. These strains were homothallic, and their spores were viable. The meiotic products analyzed so far were also homothallic.
Frequencies of Bacteriophage-Resistant and Slow Acid-Producing Variants of
Streptococcus cremoris
Authors: King W. R. , Collins E. B. , Barrett E. L.
Published: January 2020

The frequencies of bacteriophage-resistant and slow acid-producing variants in 10 purified strains of
Streptococcus cremoris
were studied. There were considerable differences among the strains in the occurrence of both slow acid-producing and phage-resistant mutants. Nevertheless, the spontaneous rates of mutation to slow acid production were three to five orders of magnitude greater than the corresponding rates of mutation to phage resistance, suggesting that slow acid production and phage resistance are not genetically linked, although they appear in cultures concomitantly. The frequencies of slow acid-producing variants among resistant and sensitive isolates from the same parent culture were similar and appeared to be strain dependent. All phage-resistant mutants tested were found to be deficient in adsorption of the homologous bacteriophage.
Levels of gram-negative bacteria, Aspergillus fumigatus, dust, and endotoxin at compost plants
Authors: Clark C S , Rylander R , Larsson L
Published: January 2020

Airborne gram-negative bacteria, endotoxins, dust, and Aspergillus fumigatus were measured in four compost plants in Sweden. At sites where material was processed, the number of airborne A. fumigatus exceeded 10(6)/m3, whereas the number of gram-negative bacteria was usually lower. Dust levels were moderate, and endotoxin levels were well below 0.5 micrograms/m3. Medical studies to evaluate the effects of this type of microbial exposure are recommended.
Broad-Host-Range Agrocin of
Agrobacterium tumefaciens
Authors: Hendson Mavis , Askjaer Lizzie , Thomson Jennifer A. , van Montagu Marc
Published: January 2020

Eighteen strains of
Agrobacterium tumefaciens
isolated from crown galls were tested for agrocin production. Of six agrocin-producing strains, one (D286) produced a broad-host-range agrocin active against strains carrying nopaline, octopine, and agropine type Ti plasmids. Sensitivity to agrocin D286 was found to map in the 11- to 18-megadalton region of the nopaline Ti plasmid pTiC58. The agrocin was partially purified, and its physical characteristics were consistent with its being a nucleotide, as is agrocin 84. Agrocin D286 was shown to inhibit DNA, RNA, and protein syntheses. Strain D286 spontaneously lost its pathogenicity, and its potential for use in the biological control of crown gall is discussed.
Methodology for recovery of chemically treated Staphylococcus aureus with neutralizing medium
Authors: Dey B P , Engley F B
Published: January 2020

Recovery results of Staphylococcus aureus ATCC 6538 treated with phenolics and quaternary ammonium compounds on Dey and Engley (D/E) neutralizing medium at various time intervals were compared by the use of two commonly used media. Two recovery processes were utilized. In one, the chemically treated organisms were plated directly onto an agar medium. In the other, the aliquot was first put in broth and then was plated with agar. By either process, the numbers and the time period for recovery of organism were greater on D/E medium.
Light and Electron Microscopic Studies of Microorganisms Growing in Rotating Biological Contactor Biofilms
Authors: Kinner Nancy E. , Balkwill David L. , Bishop Paul L.
Published: January 2020

The biofilms growing in the first compartments of two rotating biological contactors used to treat municipal wastewater were examined by light and electron microscopy. The biofilms were found to contain a complex and varied microbial community that included filamentous and unicellular bacteria, protozoa, metazoa, and (possibly) bacteriophage. The predominant microorganism among these appeared to be a filamentous bacterium that was identical to
Sphaerotilus
in both morphological and ultrastructural characteristics. It was possible to isolate a
Sphaerotilus
-like bacterium from each contactor. Both the
Sphaerotilus
filaments and the wide variety of unicellular bacteria present tended to contain poly-β-hydroxybutyrate inclusions, a probable indication that these organisms were removing carbon from the wastewater and storing it. The microbial population of the biofilms appeared to be metabolically active, as evidenced by the presence of microcolonies and dividing cells.
Effect of biotin on alkaloid production during submerged cultivation of Claviceps sp. strain SD-58
Authors: Desai J D , Desai A J , Patel H C
Published: January 2020

Addition of biotin to culture medium NL-406 significantly increased alkaloid yield during submerged cultivation of Claviceps sp. strain SD-58. Alkaloid yield was further enhanced by incorporating leucine in biotin-supplemented culture medium. Increased alkaloid production was associated with an increase in the lipid content of cells and in the number of chlamydospores. Biotin deficiency caused a reduction in alkaloid yield and a parallel decrease in lipid content and chlamydospore numbers.
l
-Serine Production by a Mutant of
Sarcina albida
Defective in
l
-Serine Degradation
Authors: Omori Kenji , Kakimoto Toshio , Chibata Ichiro
Published: January 2020

For improved
l
-serine production, an
l
-serine dehydratase-defective mutant of
Sarcina albida
IAM 1012 was obtained. In the mutant, the activities of the enzymes responsible for
l
-serine production were as high as those in the parent strain, and, at a low glycine concentration, the mutant accumulated
l
-serine more efficiently than the parent. Under optimum conditions, 21 mg of
l
-serine per ml accumulated from 100 mg of glycine per ml.
l
-Serine was isolated from a reaction mixture as
l
-serine
m
-xylene-4-sulfonate, and free amino acid was obtained in high yields by use of an ion-exchange resin. Residual glycine was recovered at a yield of 61%.
Relationships Among Rhizobia from Native Australian Legumes
Authors: Lawrie A. C.
Published: January 2020

Isolates from 12 legumes at three sites in Victoria showed a wide range of morphological, cultural, symbiotic, and serological properties. Isolates from
Acacia longifolia
var.
sophorae
and
Kennedia prostrata
were fast growing but nodulated ineffectively
Macroptilium atropurpureum
and all native legumes except
Swainsonia lessertiifolia.
Isolates from
S. lessertiifolia
showed anomalous properties intermediate between fast- and slow-growing rhizobia. All isolates from the other two sites were slow-growing “cowpea” rhizobia. Symbiotic effectiveness was usually poor, and there was no relationship between effectiveness and host taxonomy or serological affinities of the isolates. This is the first report of fast-growing rhizobia from temperate Australian woody legumes and the first report of the symbiotic effectiveness of native Australian legumes with indigenous rhizobia.