bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution of Hydrocarbon-Utilizing Microorganisms and Hydrocarbon Biodegradation Potentials in Alaskan Continental Shelf Areas
Authors: Roubal George , Atlas Ronald M.
Published: January 2020

Hydrocarbon-utilizing microorganisms were enumerated from Alaskan continental shelf areas by using plate counts and a new most-probable-number procedure based on mineralization of
14
C-labeled hydrocarbons. Hydrocarbon utilizers were ubiquitously distributed, with no significant overall concentration differences between sampling regions or between surface water and sediment samples. There were, however, significant seasonal differences in numbers of hydrocarbon utilizers. Distribution of hydrocarbon utilizers within Cook Inlet was positively correlated with occurrence of hydrocarbons in the environment. Hydrocarbon biodegradation potentials were measured by using
14
C-radiolabeled hydrocarbon-spiked crude oil. There was no significant correlation between numbers of hydrocarbon utilizers and hydrocarbon biodegradation potentials. The biodegradation potentials showed large seasonal variations in the Beaufort Sea, probably due to seasonal depletion of available nutrients. Non-nutrient-limited biodegradation potentials followed the order hexadecane > naphthalene ≫ pristane > benzanthracene. In Cook Inlet, biodegradation potentials for hexadecane and naphthalene were dependent on availability of inorganic nutrients. Biodegradation potentials for pristane and benzanthracene were restricted, probably by resistance to attack by available enzymes in the indigenous population.
Inactivation of Bacillus thuringiensis spores by ultraviolet and visible light
Authors: Griego V M , Spence K D
Published: January 2020

The inactivation of Bacillus thuringiensis spores and spores treated with two protectants, one proteinaceous and the other a commercial product, Shade, at wavelengths of the near-ultraviolet and visible spectra and at 254 nm is described. Determination of the inactivating wavelengths may be used to establish an efficient sunlight protective system for B. thuringiensis when used as a microbial insecticide.
Growth inhibition of Streptococcus mutans and Leuconostoc mesenteroides by sodium fluoride and ionic tin
Authors: Yost K G , VanDemark P J
Published: January 2020

Sodium fluoride caused inhibition of growth rate and growth levels of Streptococcus mutans with glucose as the primary energy and carbon source. Stannous fluoride increased growth lag nad caused a much greater inhibition of growth rate than did sodium fluoride. Neither compound was found to be bactericidal when culture viability was measured after 6 days of incubation. Leuconostoc mesenteroides, which lacks a phosphotransferase system for sugar transport, showed less inhibition of growth rate with both inhibitors than did S. mutans, which possesses a phosphotransferase system. Metabolism of glucose or lactose which requires enolase activity shoed sodium fluoride inhibition, whereas metabolism of arginine or pyruvate does not involve enolase activity and showed no inhibition of growth.
Identification of biotransformation products from 2,4-dinitrotoluene
Authors: McCormick N G , Cornell J H , Kaplan A M
Published: January 2020

The products of microbial transformation of 2,4-dinitrotoluene by Mucrosporium sp. were identified by thin-layer chromatography and by gas chromatography/mass spectrometry as 2-amino-4-nitrotoluene, 4-amino-2-nitrotoluene, 2,2'-dinitro-4,4'-azoxytoluene, 4,4'-dinitro-2,2'-azoxytoluene, and 4-acetamido-2-nitrotoluene. A third azoxy compound, believed to be a "mixed" type (i.e., 2,4'-azoxy or 4,2'-azoxy), was isolated but not yet identified.
Comparison of the toxicities of patulin and patulin adducts formed with cysteine
Authors: Lindroth S , von Wright A
Published: January 2020

The toxicities of patulin and of the patulin adducts formed with cysteine were compared using the mutation-sensitive strain Escherichia coli W3110 thy polA1 and its polA1+ revertant. The acute toxicities of patulin and of the adduct mixture were also compared using NMRI mice. The adduct mixture was shown by thin-layer chromatography to consist of one ninhydrin-positive, one ninhydrin- and MBTH (3-methyl-2-benzothiazolinone hydrazone)-positive, three MBTH-positive, and two ninhydrin- and MBTH-negative components. The results showed that patulin was over 100 times more toxic to E. coli than the adduct complex. Neither patulin nor the adduct mixture was found to induce the repair effect in E. coli. In the mouse feeding tests, the oral 50% lethal dose for patulin was 29 mg/kg, while that of the adduct mixture was greater than 2,370 mg/kg.
Phytoplankton uptake and excretion of assimilated nitrate in a small Canadian shield lake
Authors: Chan H K , Campbell N E
Published: January 2020

Nitrate uptake in the epilemnetic waters of a small eutrophic Canadian Shield lake was studied by using a 15N method during summer stratification. Concurrent with inhibition of primary production, 3-(3,4-dichlorophenyl)-1,1-dimethylurea inhibited NO3- assimilation. Nitrate up to 1 mg of N/liter did not affect the rate of primary production during 3 h of incubation. The NO3- fertilizer added to the lake weekly was consumed through algal assimilation in about 3 days. Excretion of the photoassimilated NO3- as dissolved organic nitrogen represented a significant portion of the nutrient incorporated by the cells. Only 40% of the NO3- -15N which disappeared could be accounted for in the particulate fraction. Although the rest was presumably excreted, only 15% of the 15N label was accounted for as cationic dissolved organic nitrogen by isotope assays. These excreted organic forms were predominantly serine and glycine in the dissolved free amino acid fraction. Bacteria as well as algae might be expected to contribute to and modify the extracellular nitrogen pool.
Airborne Bacteria in an Urban Environment
Authors: Mancinelli Rocco L. , Shulls Wells A.
Published: January 2020

Samples were taken at random intervals over a 2-year period from urban air and tested for viable bacteria. The number of bacteria in each sample was determined, and each organism isolated was identified by its morphological and biochemical characteristics. The number of bacteria found ranged from 0.013 to 1.88 organisms per liter of air sampled. Representatives of 19 different genera were found in 21 samples. The most frequently isolated organisms and their percent of occurence were
Micrococcus
(41%),
Staphylococcus
(11%), and
Aerococcus
(8%). The bacteria isolated were correlated with various weather and air pollution parameters using the Pearson product-moment correlation coefficient method. Statistically significant correlations were found between the number of viable bacteria isolated and the concentrations of nitric oxide (−0.45), nitrogen dioxide (+0.43), and suspended particulate pollutants (+0.56). Calculated individually, the total number of
Micrococcus, Aerococcus
, and
Staphylococcus
, number of rods, and number of cocci isolated showed negative correlations with nitric oxide and positive correlations with nitrogen dioxide and particulates. Statistically significant positive correlations were found between the total number of rods isolated and the concentration of nitrogen dioxide (+0.54) and the percent relative humidity (+0.43). The other parameters tested, sulfur dioxide, hydrocarbons, and temperature, showed no significant correlations.
Reversal of the silver inhibition of microorganisms by agar
Authors: Tilton R C , Rosenberg B
Published: January 2020

Increasing use of silver in the treatment of water has necessitated an examination of microbiological methods for the measurement of silver inactivation of microorganisms. Three common agar media were tested for their ability to neutralize the bacteriostatic effects of silver. Results suggested that growth media differed in their neutralizing capacity; that is, the non-inhibitory media tryptone glucose agar and Trypticase soy agar showed more neutralizing capacity than eosin methylene blue agar. Furthermore, the neutralizing effect appeared to be a function of the soluble component of the media and not of the agar itself.
Method for the Detection of Injured
Vibrio parahaemolyticus
in Seafoods
Authors: Ray B. , Hawkins Sandra M. , Hackney Cameron R.
Published: January 2020

The sensitivity of
Vibrio parahaemolyticus
cells to refrigeration and frozen storage and the development of a method for detecting injured and uninjured
V. parahaemolyticus
cells were studied. Cell suspensions in different kinds of seafood homogenates were either regrigerated (4°C) or frozen (−20°C), stored, and examined for cell survival during storage.
V. parahaemolyticus
cells were sensitive to both storage temperatures. Many cells died, and many survivors were sublethally injured. In general, refrigeration storage appeared to be more injurious than frozen storage. The initial recovery of the sublethally injured cells was highest in a nutritionally rich, nonselective liquid medium such as Trypticase soy broth, whereas maximum cell multiplication was observed in Trypticase soy broth containing 3% NaCl. The sublethally injured
V. parahaemolyticus
cells demonstrated sensitivity to the selective enrichment medium, glucose salt teepol broth. From these findings, a new method (designated as the “repair-detection” method) was developed for the isolation and enumeration of
V. parahaemolyticus.
Comparative studies between the recommended and the repair-detection methods showed that injured
V. parahaemolyticus
cells were present in commercial seafoods and that the repair-detection method was definitely more effective for the detection of total numbers of
V. parahaemolyticus
cells.
Interactions of
Bacillus licheniformis
ATCC 10716 and Normal Flora of Human Skin
Authors: Bibel D. J. , Smiljanic R. J. , Lovell D. J.
Published: January 2020

To determine whether antibiotic production might be ecologically advantageous in the survival of
Bacillus
species on human skin, we applied spores of a bacitracin-producing strain of
Bacillus licheniformis
(ATCC 10716) to the forearms of 11 volunteers. Three additional strains of
B. licheniformis
which did not synthesize antibiotics, including a mutant of ATCC 10716, were used in subsequent control trials. Samples of flora were taken from inoculated and control (opposite forearm) sites during the colonization period, generally 3 weeks. Although population densities were unaltered, changes in the carriage, composition, and bacitracin sensitivity of resident flora were related with the presence of ATCC 10716 only, which suggests that microbial interactions are important in bacillus colonization and in maintenance of normal flora. Interactions were examined in vitro by comparing growth curves of representative skin bacteria, including isolates of
Staphylococcus epidermidis, Staphylococcus saprophyticus, Micrococcus luteus
, and a large-colony diphtheroid, grown individually, in mixed culture with each other, and together in presence of each test strain of
B. licheniformis.
We observed some diminution of growth of
M. luteus
and the diphtheroid in the first mixed culture, and the diphtheroid was completely retarded in common culture with ATCC 10716. Lesser antibiotic effects were seen on the cocci, whose rank of sensitivity was similar to that in vivo. The growth of the diphtheroid was enhanced in mixed culture with those strains of bacilli which lack antibiotic activity.
Denitrification Rates in a Marine Sediment as Measured by the Acetylene Inhibition Technique
Authors: Sørensen Jan
Published: January 2020

A method has been developed for measurement of denitrification activity in sediments by application of the acetylene inhibition technique. Acetylene-saturated water was injected, at close intervals, into sediment cores which were then incubated for a few hours at the in situ temperature. Frozen segments of the cores were assayed for accumulation of N
2
O by a combined gas extraction and detection system. The segments were thawed under a stream of helium from which N
2
O (and other gases) was collected in a liquid N
2
trap, and the quantity of N
2
O was measured by gas chromatography. The maximum rate of denitrification in a coastal marine sediment was 35 nmol of N per cm
3
of sediment per day at 2.5°C, and the rate of denitrification for the total sediment was 0.99 nmol of N per m
2
per day.
Isolation of Klebsielleae from within living wood
Authors: Bagley S T , Seidler R J , Talbot H W , Morrow J E
Published: January 2020

Previous studies from this laboratory have documented the presence of coliform bacteria emanating from wooden reservoirs containing finished drinking water. Coliforms were identified as Klebsiella pneumoniae and Enterobacter spp. In the present report, evidence is presented which suggests that the origin of these coliforms is from the wood used to construct the reservoirs. In liquid expressed from freshly cut redwood, total bacterial counts in the range of 10(5) to 10(6)/ml were commonly observed. When present, coliform counts were over 10(3)/ml of expressed liquid. E. agglomerans was the most prevalent coliform present, but Klebsiella was isolated from freshly cut logs. Citrobacter freundii was also occasionally isolated. No fecal coliform-positive Klebsiella were obtained from any of the samples. Highest total bacteria and coliform counts were observed in sapwood specimens. Coliforms were present throughout sapwood as evidenced by contact plating serial sections of freshly cut wood. Scanning electron micrographs illustrate the presence of bacterial colonies within sapwood tracheids. Other wood species also contained coliform bacteria but in numbers lower than found in redwood.
Comparison of Solid-Phase Radioimmunoassays for Baculoviruses
Authors: Crawford Allan M. , Faulkner Peter , Kalmakoff James
Published: January 2020

The sensitivity and cross-reaction of four solid-phase radioimmunoassays (RIA) for
Trichoplusia ni
nuclear polyhedrosis virus containing singly enveloped virions were investigated. The detection limits of each assay were as follows: Indirect RIA, 5 ng of dissolved polyhedron antigen; direct RIA, 50 ng; indirect sandwich RIA, 200 ng; and direct sandwich RIA, 300 ng. The indirect and indirect sandwich RIAs showed considerable cross-reaction with other baculovirus antigens, but the direct and direct sandwich RIAs showed cross-reaction with only one closely related baculovirus. When microtiter plates used for the solid phase were pretreated with bovine serum albumin, nonspecific binding of labeled antibodies was reduced to a minimum. Antibodies prepared by an immunoadsorption procedure showed greater specific binding than antibodies prepared by ammonium sulfate precipitation of the immunoglobulin fraction. Highly contaminated antigen could not be detected by the indirect RIA, but the direct sandwich RIA was unaffected by antigen contamination. Antigen making up 0.0025% (wt/wt) of a sample of bird droppings could be detected by the direct sandwich RIA.
Comparative effects of ammonia and related compounds on poliovirus
Authors: Ward R L , Ashley C S
Published: January 2020

The abilities of ammonia and related compounds to inactivate poliovirus were compared. Compounds virucidal at pH 9.5 had the following order of activities: ethylamine greater than propylamine, dimethylamine, methylamine greater than ammonia greater than 2-methoxyethylamine.
Plaque Assay of Nuclear Polyhedrosis Viruses in Cell Culture
Authors: Brown Martha , Faulkner Peter
Published: January 2020

The nuclear polyhedrosis virus of
Autographa californica
has been titrated in
Spodoptera frugiperda
cells by the plaque method, using a solid overlay which does not require either the use of modified culture medium or expensive purified agarose or the addition of culture medium as a liquid layer above the solid agarose. This assay is more sensitive than that using a viscous methyl cellulose overlay but less sensitive than the end-point dilution technique. Neither
Trichoplusia ni
nor
Bombyx mori
cells were satisfactory as indicators for the assay as described, since they failed to form a stable monolayer.
Manduca sexta
cells could be utilized for assay of
A. californica
nuclear polyhedrosis virus, but the sensitivity was lower than with
S. frugiperda
cells.
Improved medium for recovery and enumeration of Pseudomonas aeruginosa from water using membrane filters
Authors: Brodsky M H , Ciebin B W
Published: January 2020

A modified mPA medium, designated mPA-C, was shown to recover Pseudomonas aeruginosa from a variety of water sources with results comparable to those with mPA-B and within the confidence limits of a most-probable-number technique. Enumeration of P. aeruginosa on mPA-C was possible after only 24 h of incubation at 41.5 degrees C, compared with 72 h of incubation required for mPA-B and 96 h of incubation for a presumptive most probable number.
Survey of human virus occurrence in wastewater-recharged groundwater on Long Island
Authors: Vaughn J M , Landry E F , Baranosky L J , Beckwith C A , Dahl M C , Delihas N C
Published: January 2020

Treated wastewater effluents and groundwater observation wells from three sewage recharge installations located on Long Island were assayed on a monthly basis for indigenous human enteroviruses and coliform bacteria for a period of 1 year. Viruses were detected in groundwater at sites where recharge basins were located less than 35 feet (ca. 10.6 m) above the aquifer. Results from one of the sites indicated the horizontal transfer of viable viruses through the groundwater aquifer.
Formaldehyde incorporation by a new methylotroph (L3)
Authors: Hirt W , Papoutsakis E , Krug E , Lim H C , Tsao G T
Published: January 2020

A number of bacterial strains have been isolated and investigated in our search for a promising organism in the production of single-cell protein from methanol. Strain L3 among these isolates was identified as an obligate methylotroph which grew only on methanol and formaldehyde as the sole sources of carbon and energy. The organism also grew well in batch and chemostat mixed-substrate cultures containing methanol, formaldehyde, and formate. Although formate was not utilized as a sole carbon and energy source, it was readily taken up and oxidized by either formaldehyde- or methanol-grown cells. The organism incorporated carbon by means of the ribulose monophosphate pathway when growing on either methanol, formaldehyde, or various mixtures of C1 compounds. Its C1-oxidation enzymes included phenazine methosulfate-linked methanol and formaldehyde dehydrogenase and a nicotinamide adenine dinucleotide-linked formate dehydrogenase. Identical inhibition by formaldehyde of the first two dehydrogenases suggested that they are actually the same enzyme. The organism had a rapid growth rate, a high cell yield in the chemostat, a high protein content, and a favorable amino acid distribution for use as a source of single-cell protein. Of special interest was the ability of the organism to utilize formaldehyde via the ribulose monophosphate cycle.
Modification of M-FC medium by eliminating rosolic acid
Authors: Presswood W G , Strong D K
Published: January 2020

Eliminating rosolic acid from M-FC medium improves the MFC procedure by allowing higher fecal coliform colony recoveries with greater ease in counting. Samples of unchlorinated and chlorinated domestic sewage, creek, lake, and river water were analyzed for fecal coliforms by standard procedures. Results of 200 comparisons of fecal coliform counts on M-FC medium without and with rosolic acid showed that higher counts were obtained 71% of the time when rosolic acid was excluded without an overgrowth of background colonies. Results from analyzing chlorinated sewage showed that eliminating rosolic acid improved the recovery of fecal coliform bacteria by 49%. A total of 1,675 blue colonies and 766 nonblue colonies were verified. Of the 1,675 blue colonies, 1,566 were confirmed as fecal coliform bacteria, for a verification of 93.5%. The percent verification of nonblue colonies as noncoliform bacteria was 84.2% (644/766).
Effects of dispersed recreational activities on the microbiological quality of forest surface water
Authors: Varness K J , Pacha R E , Lapen R F
Published: January 2020

The microbiological quality of forest surface waters in the Greenwater River watershed was examined to investigate the influence of heavy motorized camping in an area with no sanitary facilities. Indicator densities increased during weekend human-use periods when compared to weekdays. Increases in indicator densities were also noted downstream from heavily used camping areas when compared to upstream sites. Seasonal, weekly, and diurnal fluctuations in indicator densities were observed. This study suggests that potential health hazards exist in this watershed during periods of human use.
Prevalence of fungi during Skylab missions
Authors: Brockett R M , Ferguson J K , Henney M R
Published: January 2020

Samples for mycological analysis were collected from surfaces in the Skylab spacecraft before launch and during flight for each manned mission. Fungal contamination levels were low during the first two flights; however, the species recovered were different for each mission. On the third mission, widespread contamination of the Skylab spacecraft with Aspergillus and Pencillium spp. was detected. This contamination was traced to several contaminated space suit undergarments.
Fungal contamination and mycotoxin detection of powdered herbal drugs
Authors: Hitokoto H , Morozumi S , Wauke T , Sakai S , Kurata H
Published: January 2020

Forty-nine powdered herbal drugs were analyzed for their mold profile and for the potential presence of three mycotoxins (aflatoxin, sterigmatocystin, ochratoxin A). Aspergillus and Penicillium species were predominant, but Rhizopus, Mucor, Cladosporium, and Aureobasidium spp. were also found in a few samples. Mycotoxins were not detected in any samples, and only one isolated culture was found to be a mycotoxin producer on laboratory media.
Influence of crossdrafts on the performance of a biological safety cabinet
Authors: Rake B W
Published: January 2020

A biological safety cabinet was tested to determine the effect of crossdrafts (such as those created by normal laboratory activity or ventilation) upon the ability of the cabinet to protect both experiments and investigators. A simple crossdraft, controllable from 50 to 200 feet per min (fpm; 15.24 to 60.96 m/min), was created across the face of the unit. Modifications of standardized procedures involving controlled bacterial aerosol challenges provided stringent test conditions. Results indicated that, as the crossflow velocities exceeded 100 fpm, the ability of the cabinet to protect either experiments or investigators decreased logarithmically with increasing crossdraft speed. Because 100 fpm is an airspeed easily achieved by some air conditioning and heating vents (open windows and doorways may create velocities far in excess of 200 fpm), the proper placement of a biological safety cabinet within the laboratory--away from such disruptive air currents--is essential to satisfactory cabinet performance.
Kinetic Parameters of the Conversion of Methane Precursors to Methane in a Hypereutrophic Lake Sediment
Authors: Strayer Richard F. , Tiedje James M.
Published: January 2020

The kinetic parameters

K
m

,

V
max

,

T
t

(turnover time), and
v
(natural velocity) were determined for H
2
and acetate conversion to methane by Wintergreen Lake sediment, using short-term (a few hours) methods and incubation temperatures of 10 to 14°C. Estimates of the Michaelis-Menten constant,

K
m

, for both the consumption of hydrogen and the conversion of hydrogen to methane by sediment microflora averaged about 0.024 μmol g
−1
of dry sediment. The maximal velocity,

V
max

, averaged 4.8 μmol of H
2
g
−1
h
−1
for hydrogen consumption and 0.64 μmol of CH
4
g
−1
h
−1
for the conversion of hydrogen to methane during the winter. Estimated natural rates of hydrogen consumption and hydrogen conversion to methane could be calculated from the Michaelis-Menten equation and estimates of

K
m

,

V
max

, and the in situ dissolved-hydrogen concentration. These results indicate that methane may not be the only fate of hydrogen in the sediment. Among several potential hydrogen donors tested, only formate stimulated the rate of sediment methanogenesis. Formate conversion to methane was so rapid that an accurate estimate of kinetic parameters was not possible. Kinetic experiments using [2-
14
C]acetate and sediments collected in the summer indicated that acetate was being converted to methane at or near the maximal rate. A minimum natural rate of acetate conversion to methane was estimated to be about 110 nmol of CH
4
g
−1
h
−1
, which was 66% of the

V
max

(163 nmol of CH
4
g
−1
h
−1
). A 15-min preincubation of sediment with 5.0 × 10
−3
atm of hydrogen had a pronounced effect on the kinetic parameters for the conversion of acetate to methane. The acetate pool size, expressed as the term

K
m

+

S
n

(

S
n

is in situ substrate concentration), decreased by 37% and

T
t

decreased by 43%. The

V
max

remained relatively constant. A preincubation with hydrogen also caused a 37% decrease in the amount of labeled carbon dioxide produced from the metabolism of [
U
-
14
C]valine by sediment heterotrophs.
Depression of activity of intestinal mucosal alkaline phosphatase with gastrointestinal microorganisms
Authors: Kawai Y , Ishii T , Morotomi M , Mutai M
Published: January 2020

Depression of intestinal alkaline phosphatase activity can be caused by the formation of the microbial ecosystem with several kinds of viable microorganisms in rats.
Mollicellins: mutagenic and antibacterial mycotoxins
Authors: Stark A A , Kobbe B , Matsuo D , Büchi G , Wogan G N , Demain A L
Published: January 2020

Eight mollicellins (depsidones) were assayed for mutagenicity and antibacterial activity in Salmonella/microsome tests involving histidine reversion and forward mutation to 8-azaguanine resistance. Two of them, mollicellins C and E, which contain a 3-methylbutenoic acid moiety, were mutagenic and bactericidal for Salmonella typhimurium in the absence of microsomes. Mollicellins D and F, each containing a chlorine atom, were bactericidal but not mutagenic. The mutagenic activity was completely abolished and the antibiotic activity was greatly reduced by coincubation with rat liver microsomes.
Incidence of
Vibrio parahaemolyticus
Bacteriophages and Other
Vibrio
Bacteriophages in Marine Samples
Authors: Baross John A. , Liston John , Morita Richard Y.
Published: January 2020

Vibrio
bacteriophages were isolated by enrichment from 177 of 643 samples of marine molluscan shellfish, crustaceans, seawater, and sediments. The predominant bacteriophage types isolated were specific for some strains of
Vibrio parahaemolyticus.
A high frequency of phage isolations was also observed with strains of agar-digesting vibrios (21 of 56) and psychrophilic vibrios (14 of 72) that were originally isolated from non-shellfish growing areas. No bacteriophages were isolated against
V. alginolyticus
and only rarely for
V. anguillarum
even though these were the two most abundant species found in near-shore environments. No
V. cholerae
phages were isolated. It was also determined from quantitative studies on the Pacific oyster (
Crassostrea gigas
) obtained from two environments in Washington and Oregon that the titers of
V. parahaemolyticus
bacteriophages increased with increasing seasonal water temperatures and that this was proportional to the increase in numbers of mesophilic vibrios and not with the incidence of
V. parahaemolyticus.
Titers of
V. parahaemolyticus
bacteriophages occasionally exceeded 10
6
per g of oyster during the summer months. Specific
V. parahaemolyticus
bacteriophages were also isolated from market seafoods and other marine samples that originated in cold environments where no mesophilic vibrios are expected to be found. The possibility that
V. parahaemolyticus
bacteriophages originate from
Vibrio
spp. other than
V. parahaemolyticus
and the role of these bacteriophages in the ecology of marine vibrios are discussed.
Autoradiography and Epifluorescence Microscopy Combined for the Determination of Number and Spectrum of Actively Metabolizing Bacteria in Natural Waters
Authors: Meyer-Reil Lutz-Arend
Published: January 2020

A technique is described for the determination of bacterial numbers and the spectrum of actively metabolizing cells on the same microscopic preparation by a combined autoradiography/epifluorescence microscopy technique. Natural bacterial populations incubated with [
3
H]glucose were filtered onto 0.2-μm Nuclepore polycarbonate membranes. The filters were cut into quarters and fixed on the surface of glass slides, coated with NTB-2 nuclear track emulsion (Kodak), and exposed to the radiation. After processing, the autoradiographs were stained with acridine orange. A combination of overstaining on the slightly alkaline side and gradual destaining on the acid side of neutrality gave the best results. Epifluorescence microscopy revealed bright-orange fluorescent cells with dark-silver grains associated against a greenish-to-grayish background. Based on the standardization curves, detection of actually metabolizing cells was optimal when cells were incubated with 1 to 5 μCi of [
3
H]glucose per ml of sample for 4 h and the autoradiographs were exposed to NTB-2 emulsion at 7°C for 3 days. In water samples taken immediately above sandy sediments at beaches of the Kiel Fjord and the Kiel Bight (Baltic Sea, FRG), between 2.3 and 56.2% (average, 31.3%) of the total number of bacteria were actually metabolizing cells. Spearman rank correlation analysis revealed significant interrelationships between the number of active bacteria and the actual uptake rate of glucose.
Effect of hydrostatic tensile stress on the growth of Escherichia coli and Bacillus cereus
Authors: O'Brien W J , Walker M C , Fan P L , Johnston W M
Published: January 2020

The specific growth rates of Escherichia coli and Bacillus cereus were measured for growth media in a flask, a lens-plate arrangement simulating an isolated capillary space, and a lens-plate arrangement under hydrostatic tensile stress. The specific growth rates of the bacteria were the same for the flask and lens-plate arrangement without hydrostatic tensile stress, but were enhanced when the growth media were subjected to hydrostatic tensile stress. The enhanced specific growth rates reached steady values at a tensile stress of 40 pascals. The effect was observed up to tensile stresses of around 100 pascals. The maximum increase in specific growth rate was 25% for E. coli and 22% for B. cereus.
New medium for rapid screening and enumeration of Clostridium perfringens in foods
Authors: Erickson J E , Deibel R H
Published: January 2020

A rapid and sensitive procedure for estimating low numbers of Clostridium perfringens has been investigated and compared to methods used currently in the food industry. The new liquid medium, RPM (rapid perfringens medium), was compared with sulfite-polymyxin-sulfadiazine agar and tryptose-sulfite-cycloserine agar in recovery studies with naturally contaminated and with inoculated foods. The medium consists of a mixture of litmus milk and fluid thioglycolate medium fortified with glucose, peptone, gelatin, yeast extract, sodium chloride, and ferrous sulfate. Selectivity is based on an antibiotic system (polymyxin B sulfate and neomycin sulfate) incorporated into the medium, coupled with an incubation temprature of 46 to 48 degrees C for 24 h. Tubes were scored as positive if a stormy fermentation was observed. All tubes demonstrating stormy fermentation were confirmed as containing C. perfringens. Of a total of 774 naturally contaminated food samples, 546 samples (71%) were found to contain C. perfringens with RPM, whereas only 168 (22%) of the samples were positive using sulfite-polymyxin-sulfadiazine agar. C. perfringens was isolated from 71% of 85 other samples using RPM as compared to 14% with tryptose-sulfite-cycloserine agar. Enumeration studies on 14 individual samples using the most probable number technique also demonstrated greater sensitivity with RPM.
Production and Ecological Significance of Yeast Cell Wall-Degrading Enzymes from Oerskovia
Authors: Mann J. W. , Jeffries T. W. , Macmillan J. D.
Published: January 2020

Motile actinomycetes capable of degrading walls of viable yeast cells were isolated from soil and identified as
Oerskovia xanthineolytica.
A lytic assay based on susceptibility of enzyme-treated cells to osmotic shock was developed, and 10 of 15 strains of
O. xanthineolytica, Oerskovia turbata
, and nonmotile
Oerskovia
- like organisms from other collections were found to possess yeast lytic activities. All lytic strains produced laminaranase and α-mannanase, but the amounts, determined by reducing group assays, were not proportional to the observed lytic activities. The
Oerskovia
isolates demonstrated chemotactic, predatory activity against various yeast strains and killed yeasts in mixed cultures. Of 15 carbon sources tested for production of lytic enzyme, purified yeast cell walls elicited the highest activity. Glucose repressed enzyme production and caused cells to remain in the microfilamentous and motile rod stages of the
Oerskovia
cell cycle. Crude lytic activity was optimal at pH 5.6 to 7.0 and inactivated by heating for 6 min at 50°C. Partial purification by isoelectric focusing showed that all lytic activity was associated with four β-(1→3)-glucanases. The absence of protein disulfide reductase,
N
-acetyl-β-
d
-hexosaminidase, and phosphomannanase in crude preparations indicated that the principal enzyme responsible for yeast wall lysis was a β-(1→3)-glucanase that produced relatively little reducing sugar from yeast glucan.
Cellulolytic Enzyme System of
Thermoactinomyces
sp. Grown on Microcrystalline Cellulose
Authors: Hägerdal Bärbel G. R. , Ferchak John D. , Pye E. Kendall
Published: January 2020

The carboxymethyl-cellulase and Avicelase activities of
Thermoactinomyces
sp., strain YX, were produced simultaneously with cell growth. Throughout the growth phase these activities were primarily extracellular, with up to 50% adsorbed to residual cellulosic substrate at any one time. On the other hand, the β-glucosidase activity was associated with the culture solids throughout the entire fermentation and appears to be intracellular. Preparative isoelectric focusing of the culture filtrate, in the pH range 3 to 5, separated three major fractions with cellulolytic activities towards both carboxymethyl-cellulose and Avicel. Based on the carboxymethyl-cellulase and Avicelase activities of these separated fractions, it was not possible to discriminate between endo- and exoglucanases produced by
Thermoactinomyces
sp. Analytical isoelectric focusing of culture filtrates obtained throughout the growth phase of
Thermoactinomyces
indicated that all the extracellular cellulolytic enzymes are produced and released into the culture filtrate simultaneously, with no evidence of a sequential appearance of the various enzymes or isoenzymes.
Disappearance of patulin during alcoholic fermentation of apple juice
Authors: Stinson E E , Osman S F , Huhtanen C N , Bills D D
Published: January 2020

Eight yeast strains were used in three typical American processes to ferment apple juice containing 15 mg of added patulin per liter. Patulin was reduced to less than the minimum detectable level of 50 microgram/liter in all but two cases; in all cases, the level of patulin was reduced by over 99% during alcoholic fermentation. In unfermented samples of apple juice, the concentration of added patulin declined by only 10% when the juice was held for 2 weeks, a period equivalent to the time required for fermentation.
Characterization of methanol-oxidizing bacteria by their growth response to various chemicals
Authors: Kühn I
Published: January 2020

"Fingerprints" of strains of methanol-oxidizing bacteria were obtained by exposing them to a set of chemicals which could stimulate or inhibit the growth. The chemicals gave quantitative results, which were used to calculate the similarities between the strains. The method has been used for establishing identity or nonidentity between isolates, and its use in a search for random mutants is also outlined.
Surface kinetic test method for determining rate of kill by an antimicrobial solid
Authors: Isquith A J , McCollum C J
Published: January 2020

An antimicrobial-surface kinetic test which maximizes probability of cell-to-surface contact has been developed. The measurement of rate of kill by a nonleaching antimicrobial surface is based on the number of surviving bacterial cells at specific times of exposure to various amounts of total treated surface area of test substrate. This method gives information for direct comparison of rate of kill for a variety of antimicrobial surfaces in terms of rate of kill per square centimeter of surface area. Data obtained by this method can also give valuable dose response application information as an indication of the exponential efficiency of concentration in terms of treated surface area.
Lactose Variability of
Escherichia coli
in Thermally Stressed Reactor Effluent Waters
Authors: Kasweck K. L. , Fliermans C. B.
Published: January 2020

Lactose-utilizing and nalidixic acid-resistant populations of
Escherichia coli
, having an optimum growth temperature of 37°C, were placed in modified diffusion chambers. The chambers were submerged in the epilimnion and hypolimnion of a 1,100-hectare lake (Par Pond) which receives cooling water from a nuclear production reactor. Control chambers were placed in a deep-water reservoir and a Flowing-Streams Laboratory, both of which had comparable temperatures to Par Pond. The populations of
E. coli
were sampled regularly for up to 3 weeks. Viability of the bacteria was determined by dilution plating to nutrient agar followed by replicate plating onto selective medium to determine lactose utilization and nalidixic acid sensitivity. Initial populations of
E. coli
were lactose positive but changed to lactose negative in Par Pond when the reactor was operating (i.e., cooling water from the heat exchangers was being discharged to the lake). This alteration occurred most rapidly in the chambers closest to the cooling-water discharge point. Such changes did not occur in a deep-water reservoir, in Par Pond when the reactor was not operating, or in the Flowing-Streams Laboratory. The nalidixic acid-resistant characteristic remained stable regardless of the chambers' placement or reactor operations. Although the reasons for such alterations are unclear, it appears that lactose-negative populations of
E. coli
are selected for in these reactor effluent waters. The loss of the lactose characteristic prevents the recognition and identification of
E. coli
in this cooling lake (when the reactor is operating) and may prevent the assessment of water quality based on coliform recognition.
Improved identification of methanogenic bacteria by fluorescence microscopy
Authors: Doddema H J , Vogels G D
Published: January 2020

Methanogenic bacteria can be tentatively identified by fluorescence microscopy. This technique was improved by carefully selecting a series of excitation and barrier filters that matched the excitation and emission spectra of some unique coenzymes viz., F420 and F350, in methanogenic bacteria.
Production of xanthomegnin and viomellein by species of Aspergillus correlated with mycotoxicosis produced in mice
Authors: Robbers J E , Hong S , Tuite J , Carlton W W
Published: January 2020

By using thin-layer chromatography and infrared spectroscopy, xanthomegnin and viomellein have been isolated and identified from species of the Aspergillus ochraceus group. A correlation was established between the occurrence of these fungal quinones in the fungal cultural products and the ability of these products to induce mycotoxicosis in mice. In addition, a method was employed to estimate the amount of xanthomegnin and viomellein produced by the fungi.
Growth characteristics of atypical mycobacteria in water and their comparative resistance to disinfectants
Authors: Carson L A , Petersen N J , Favero M S , Aguero S M
Published: January 2020

With the increasing significance of group IV atypical mycobacteria as etiological agents in a variety of infections, studies were conducted to determine their growth capabilities in water and their comparative resistance to disinfectants used to decontaminate hospital equipment. Isolates of Mycobaterium chelonei (TM strains) from peritoneal fluids of patients and peritoneal dialysis machines were able to multiply in commercial distilled water, with generation times at 25 degrees C ranging from 8 to 15 h. Levels of 10(5) to 10(6) cells per ml were attained, and these stationary-phase populations declined only slightly over a 1-year period. Results of studies to determine resistance to disinfectants showed the following. (i) TM strains of M. chelonei cultured in commercial distilled water showed survivors in 2% aqueous formaldehyde (HCHO) solutions up to 24 h; in 8% HCHO, only a 2-log reduction in viable counts was observed over a 2-h sampling period. Reference ATCC strains of M. chelonei and M. fortuitum were rapidly inactivated, with no survivors after 2 h of exposure to 2% HCHO or 15 min of exposure to 8% HCHO. (ii) In 2% alkaline glutaraldehyde, TM strains survived 60 min. whereas ATCC strains showed no survivors after 2 min of contact time. (iii) All M. chelonei and M. fortuitum strains survived 60 min of exposure to concentrations of 0.3 and 0.7 microgram of free chlorine per ml at pH 7.
Simultaneous determination of the total number of aquatic bacteria and the number thereof involved in respiration
Authors: Zimmermann R , Iturriaga R , Becker-Birck J
Published: January 2020

The electron transport system of respiring organisms reduces 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride (INT) to INT-formazan. Respiring bacteria deposit accumulated INT-formazan intracellularly as dark red spots. Corresponding to electron transport system activity, these deposits attain a size and a degree of optical density which allows them to be examined by light microscopy. If polycarbonate filters and epifluorescence microscopy are applied to analyze an INT-treated water sample, it is possible to differentiate between respiring and apparently nonrespiring bacteria. This differentiation, which permits determinations of the total number of bacteria and the proportion thereof involved in respiration, is realized directly within one and the same microscopic image. Initial applications of the present method for hydrobiological purposes showed that the proportion of respiring aquatic bacteria ranged between 6 to 12% (samples taken from coastal areas of the Baltic Sea) and 5 to 36% (samples taken from freshwater lakes and ponds). Cells of 1.6 to 2.4 micrometer (freshwater) and 0.4 micrometer (Baltic Sea) account for the highest proportion of respiring bacteria.
Coliform aerosols generated from the surface of dewatered sewage applied to a forest clearcut
Authors: Edmonds R L , Littke W
Published: January 2020

Concentrations of airborne coliform bacteria as high as 1.5 X 10(4) m-3 were observed 8 cm above anaerobically digested sewage sludge applied to a forest clearcut. Dry conditions and high wind speeds tended to favor aerosol generation.
Microbial impact of Canada geese (Branta canadensis) and whistling swans (Cygnus columbianus columbianus) on aquatic ecosystems
Authors: Hussong D , Damar� J M , Limpert R J , Sladen W J , Weiner R M , Colwell R R
Published: January 2020

Quantitative and qualitative analyses of the intestinal bacterial flora of Canada geese and whistling swans were carried out with the finding that wild birds harbor significantly more fecal coliforms than fecal streptococci. The reverse was typical of captive and fasting birds. Neither Salmonella spp. nor Shigella spp. were isolated from 44 migratory waterfowl that were wintering in the Chesapeake Bay region. Enteropathogenic Escherichia coli were detected in seven birds. Geese eliminated 10(7) and swans 10(9) fecal coliforms per day. Results of in situ studies showed that large flocks of waterfowl can cause elevated fecal coliform densities in the water column. From the data obtained in this study, it is possible to predict the microbial impact of migratory waterfowl upon aquatic roosting sites.
Estimation of Sediment Denitrification Rates at In Situ Nitrate Concentrations
Authors: Oren Aharon , Blackburn Thomas H.
Published: January 2020

The denitrification rates in a marine sediment, estimated by using
15
N-nitrate,

V
max
, K
m

, and sediment nitrate concentrations, were 12.5 and 2.0 nmol of N
2
-N cm
−3
day
−1
at 0 to 1 and 1 to 3 cm, respectively, at 12�C. The total rate was 165 nmol of N
2
-N m
−2
day
−1
.
Accelerated Mineralization of Two Organophosphate Insecticides in the Rhizosphere
Authors: Hsu T.-S. , Bartha R.
Published: January 2020

Numerous xenobiotic compounds, including the organophosphate insecticides
O, O
-diethyl-
O
-(2-isopropyl-6-methyl-4-pyrimidinyl) phosphorothioate (diazinon) and
O, O
-diethyl-
O-p
-nitrophenyl phosphorothioate (parathion), appear to be degraded in the soil environment by an initial cometabolic attack. Comparing the mineralization rates of radiolabeled diazinon and parathion in root-free and in rhizosphere soil, we tested our hypothesis that, because of the presence of root exudates, the rhizosphere is an especially favorable environment for such co-metabolic transformations. The insecticides were added individually at 5 μg/g to sealed flasks containing either soil permeated by the root system of a bush bean plant or identical soil without roots. Periodically, the flask atmospheres were flushed through traps and the evolved
14
CO
2
was quantitated. Bush bean plant roots without associated rhizosphere microorganisms failed to produce a significant amount of
14
CO
2
. During 1 month of incubation, rhizosphere flasks mineralized 12.9 and 17.9% of the added diazinon and parathion radiocarbon, respectively, compared to 5.0 and 7.8% by the soil without roots. The mineralization of parathion but not of diazinon was stimulated in a similar manner when soil without roots was repeatedly irrigated with a root exudate produced in aseptic solution culture. Viable counts of microorganisms on soil extract agar were not significantly altered by root permeation or by root exudate treatment of the soil, leaving population selection and/or enhanced cometabolic activity as the most plausible interpretations for the observed stimulatory effects. Rhizosphere interactions may substantially shorten the predicted half-lives of some xenobiotic compounds in soil.
Fluid accumulation in mouse ligated intestine inoculated with Clostridium perfringens enterotoxin
Authors: Yamamoto K , Ohishi I , Sakaguchi G
Published: January 2020

Clostridium perfringens enterotoxin, when inoculated into the ligated intestinal loop of mice, caused marked distension due to fluid accumulation. The increase in weight of the intestinal loop was proportional to the log dose of enterotoxin within a range from 1 to 16 micrograms. The fluid accumulation was arrested by washing the loop with saline or by injection of the specific anti-enterotoxin serum into the loop 5 or even 30 min after inoculation of the enterotoxin. A significant increase in weight of the loop was found as early as 10 min after inoculation of the toxin. These results may suggest that entergotoxin is neither bound firmly to the mucosal membrane nor permeates into the cells of the intestinal wall. The mouse intestinal loop test is economical, simple to perform, and applicable for quantitative determination of the enteropathogenic activity of C. perfringens enterotoxin.