bluuebunny/crossref_metadata_2025 huggingface dataset:
Transformation of Elemental Mercury by Bacteria
Authors: Holm Harvey W. , Cox Marilyn F.
Published: December 2020

The fate and impact of elemental mercury in closed bacterial cultures were examined. The quantity of elemental mercury oxidized by bacteria ranged from small amounts for
Pseudomonas aeruginosa, P. fluorescens, Escherichia coli
, and
Citrobacter
to essentially all of the added elemental mercury for
Bacillus subtilis
and
B. megaterium
. The percentage of the total mercury in the system associated with bacterial cells ranged from 18.6 43.2%. Growth of the two
Pseudomonas
species was inhibited by elemental mercury, whereas growth of the other cultures was not distinguishable from that in mercury-free controls. No methylmercury was formed by the six cultures within 48 h.
Production of Hydrogen Cyanide by
Pseudomonas flurescens
Authors: Freeman L. R. , Angelini P. , Silverman G. J. , Merritt C.
Published: December 2020

Two
Pseudomonas fluorescens
isolates were found to produce hydrogen cyanide when cultured on either Trypticase soy agar supplemented with 0.5% yeast extract or on irradiation-sterilized chicken.
Effects of Cadmium on the Growth and Uptake of Microorganisms
Authors: Doyle J. J. , Marshall R. T. , Pfander W. H.
Published: December 2020

Six species of microorganisms,
Escherichia coli, Bacillus cereus, Lactobacillus acidophilus, Staphylococcus aureus, Streptococcus faecalis
and
Actinomyces niger
, were grown under suitable conditions in appropriate media. Cadmium chloride was added to provide 0, 5, 10, 20, 40, and 80 μg of Cd per ml. At 40 and 80 μg of Cd per ml.
E. coli
and
B. cereus
grew well and the other species were repressed. Cd uptake patterns differed significantly among the species tested. The significance of these data with respect to Cd in food chains is discussed.
Rhythmic Changes in Dry Heat Resistance of
Bacillus subtilis
Spores After Rapid Changes in pH
Authors: Heckly Robert J. , Dimatteo J.
Published: December 2020

Heat resistance of freeze-dried
Bacillus subtilis
spores varied in a rhythmic manner as a function of time between acidification to about pH 1.5 and freezing. A comparable rapid shift to pH 11 produced little change in resistance to heat.
Degradation of Lindane by
Escherichia coli
Authors: Francis A. J. , Spanggord R. J. , Ouchi G. I.
Published: December 2020

Lindane was degraded by
Escherichia coli
isolated from rat feces. About 10% of the added lindane was metabolized by the bacterium in Trypticase soy broth containing the pesticide. A single metabolite, 2,3,4,5,6-pentachloro-1-cyclohexene, was detected and identified by gas chromatography and mass spectrometry.
Purification and Properties of
Clostridium botulinum
Type F Toxin
Authors: Yang K. H. , Sugiyama H.
Published: December 2020

Clostridium botulinum
type F toxin of proteolytic Langeland strain was purified. Toxin in whole cultures was precipitated with (NH
4
)
2
SO
4
. Extract of the precipitate was successively chromatographed on diethylaminoethyl-cellulose at pH 6.0,
O
-(carboxymethyl) cellulose at pH 4.9, Sephadex G-200 at pH 8.1, quaternary aminoethyl-Sephadex at pH 4.9, and finally diethylaminoethyl-cellulose at pH 8.1. The procedure recovered 14% of the toxin assayed in the starting culture. The toxin was homogeneous by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, double gel diffusion serology, and isoelectric focusing. Purified toxin had a molecular weight of 150,000 by gel filtration and 155,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Specific toxicity was 9.6 × 10
6
mean lethal doses per absorbancy (278 nm) unit. Sub-units of 105,000 and 56,000 molecular weight are found when purified toxin is treated with a disulfide reducing agent and electrophoresed on sodium dodecyl sulfate-polyacrylamide gels. Reciprocal cross neutralizations were demonstrated when purified type F and E toxins were reacted with antitoxins which were obtained with immunizing toxoids prepared with purified toxins.
Persistence and Biodegradation of Spilled Residual Fuel on an Estuarine Beach
Authors: Pierce R. H. , Cundell A. M. , Traxler R. W.
Published: December 2020

The enrichment of hydrocarbon-degrading bacteria and the persistence of petroleum hydrocarbons on an estuarine beach after a spill of residual fuel oil on 11 April 1973 in Upper Narragansett Bay, R. I. was investigated. A rapid enrichment occurred during days 4 to 16 after the oil spill and a significant population of hydrocarbon-degrading bacteria was maintained in the beach sand for at least a year. The concentration of petroleum hydrocarbons in the mid tide area declined rapidly during the bacterial enrichment period, remained fairly constant throughout the summer, and then declined to a low concentration after 1 year. An increased concentration of branched and cyclic aliphatic hydrocarbons in the low-tide sediment 128 days after the spill suggested a migration of hydrocarbons during the summer. Hydrocarbon biodegradation was apparent during the winter months at a rate of less than 1 μg of hydrocarbon per g of dry sediment per day.
Interaction of Lead and Bacterial Lipids
Authors: Tornabene Thomas G. , Peterson Steven L.
Published: December 2020

Studies on the interaction of lead with lipid components indicate that individual lipids do not provide specific stable binding sites for lead, but that natural membrane lipid mixtures may simply provide an environment suitable for nucleation of lead.
Inhibition of Phenylamide Hydrolysis by
Bacillus sphaericus
with Methylcarbamate and Organophosphorus Insecticides
Authors: Engelhardt G. , Wallnöfer P. R.
Published: December 2020

The degradation of the phenylamide herbicides monolinuron, linuron, and solan by cultures of
Bacillus sphaericus
ATCC 12123 was inhibited by the methylcarbamate insecticides metmercapturon, aldicarb, propoxur, and carbaryl and by the organophosphorus insecticides fenthion and parathion. The extent of inhibition was largest with metmercapturon and smallest with parathion. Inhibition of hydrolysis of the two phenylurea herbicides was greater than of the acylanilide compound. Tests with crude enzyme preparations of aryl acylamidase derived from
B. sphaericus
showed that the inhibition of the hydrolysis of linuron with methylcarbamates is a competitive one. The insecticides tested did not induce the enzyme, nor could they serve as its substrate.
Extracellular Polysaccharide from the Black Yeast NRRL Y-6272: Improved Methods for Preparing a High-Viscosity, Pigment-Free Product
Authors: Sanford Paul A. , Burton Kermit A. , Watson Paul R. , Cadmus Martin C. , Jeanes Allene
Published: December 2020

When the extracellular polysaccharide from the black yeast NRRL Y-6272, composed of two parts
N
-acetyl-D-glucosamine and one part
N
-acetyl-D-glucosaminuronic acid, is isolated at maximum culture viscosity, adhering black pigment gives the polysaccharide preparations a gray-to-black appearance. Precipitation of the polysaccharide from cell-free culture supernatants with either ethanol or hexadecyltrimethylammonium bromide failed to remove the pigment. Various other methods were therefore tried for obtaining a high-viscosity polysaccharide product free of pigment. By systematically varying ingredients of defined and semidefined media, an improved medium was found that not only gave polysaccharide preparations of increased viscosity, but also increased yield. A key ingredient in this medium is L-asparagine. Also, adding autoclaved bovine serum albumin or egg albumin to this medium at the time of inoculation allowed a pigment-free polysaccharide to be isolated by standard procedures. None of several other proteins or synthetic polyamides tested were as effective as bovine serum albumin or egg albumin. In an alternate approach, pink mutants, obtained by irradiation of the parent black strain with ultraviolet light, apparently produce the same extracellular polysaccharide free of any pigment but in lower yields or inferior in quality.
Method for Detecting Small Numbers of
Vibrio cholerae
in Very Polluted Substrates
Authors: Sechter I. , Gerichter Ch.B. , Cahan D.
Published: December 2020

A method is presented for the indirect detection of
Vibrio cholerae
by the multiplication of two specific bacteriophages: ϕH74/64 for El-Tor vibrios, and phage group IV (Mukerjee) for classical vibrios. The product to be examined is seeded in alkaline tryptone water for enrichment, as in the classical method, and is then incubated for 6 h at 37 C. Thereafter, a loopful is transferred to each of two nutrient broth (pH 9) tubes. One of these receives a drop of phage ϕH74/64; the other receives a drop of phage group IV. The stock phages are diluted so as to contain about 3,800 plaque-forming units in one drop; this is the maximum amount which, when added to 10 ml of broth, will not be detected in a loopful of 1 mm diameter. The tubes containing phage φH74/64 are incubated at 42 C; those with phage group IV are incubated at 37 C. After 18 h the cultures are killed by agitation with chloroform, and a 1-mm loopful is deposited on a layer seeded with the detector strains: Makassar 757 for El-Tor phage and
V. cholerae
154 for classical cholera phage. After 4 to 5 h at 37 C, lysis appears on the spot areas if there has been phage multiplication in the respective broth tubes. With experimentally contaminated sewage water, vegetables, or stools, 1 to 10 cholera vibrios were detected in every sample. In rare cases, false-positive results were obtained by multiplication of the phage on non-cholera vibrios.
Tremorgenic Mycotoxins from
Aspergillus Caespitosus
Authors: Schroeder H. W. , Cole R. J. , Hein H. , Kirksey J. W.
Published: December 2020

Two tremorgenic mycotoxins were isolated from
Aspergillus caespitosus
, and identified as verruculogen and fumitremorgin B. They were produced at the rate of 172 and 325 mg per kg, respectively, on autoclaved cracked field corn.
Radiation Resistance of Spores of Some
Clostridium perfringens
Strains
Authors: Clifford Walter J. , Anellis Abe
Published: December 2020

Clostridium perfringens
spores (eight strains) were irradiated in a model system with
60
Co gamma rays at -30 C. The quantal response data were analyzed with extreme value statistics. It was found (at the 95% confidence level) that all eight strains followed the same rate of death and that this rate was probably (at the 95% level) not exponential. The statistics did not exclude, however, a normal, lognormal, Weibull, or related rate of spore kill. A more definitive study would be required to distinguish between the latter distributions.
Sequential Growth of Bacteria on Crude Oil
Authors: Horowitz Amikam , Gutnick David , Rosenberg Eugene
Published: December 2020

By modification of the enrichment culture procedure three bacterial strains capable of degrading crude oil in sea water were isolated in pure culture, UP-2, UP-3, and UP-4. Strain UP-2 appears to be highly specialized for growth on crude oil in sea water since it showed strong preference for oil or oil degradation products as substrates for growth, converted 66% of the oil into a form no longer extractable by organic solvents, quantitatively degraded the paraffinic fraction (gas chromatographic analysis), emulsified the oil during exponential growth, and produced 1.6 × 10
8
cells per mg of oil. After exhaustive growth of UP-2 on crude oil the residual oil supported the growth of UP-3 and UP-4, but not a previously isolated oil-degrading bacterium, RAG-1. Strains UP-2, UP-3, and UP-4 grew on RAG-1-degraded oil (specifically depleted of
n
-alkanes). The growth of UP-3 and UP-4 on UP-2 and RAG-1-degraded oil resulted in the production of new paraffinic compounds as revealed by gas chromatography. When the four strains were grown either together in a mixed culture or sequentially, there was over 75% oil conversion. By plating on selective media, growth of the individual strains was measured kinetically in the reconstituted mixed culture, revealing competition for common growth substances (UP-2 and RAG-1), enhanced die-off (UP-2), and stabilization (UP-4) during the stationary phase.
Toxigenic Fungi in Food
Authors: Davis N. D. , Wagener R. E. , Dalby D. K. , Morgan-Jones G. , Diener U. L.
Published: December 2020

Forty-five fungal isolates from moldy supermarket foods were tested for toxicity to brine shrimp, and twenty-two of these isolates were subsequently tested for toxicity to chicken embryos. Highly toxigenic fungi were
Cladosporium sphaerospermum
from a bakery product,
Fusarium oxysporum
from carrots,
F. solani
from cabbage,
Aspergillus niger
and
Penicillium corylophilum
from bread,
P. cyclopium
and
P. herquei
from corn meal,
P. lanosum
from onions,
P. steckii
from chocolate syrup,
Penicillium
sp. from jelly, and
Rhizopus nigricans
isolates from sweet potato, applesauce, and strawberries. Approximately one-third of the fungal cultures were moderately to highly toxigenic to brine shrimp and chicken embryos, while several additional cultures were slightly toxigenic.
Incidence of
Listeria monocytogenes
in Nature
Authors: Weis J. , Seeliger H. P. R.
Published: December 2020

During a research project on the occurrence of
Listeria monocytogenes
194 strains were isolated in southern West Germany during the years 1972 to 1974: 154 from soil and plant samples (20.3%), 16 from feces of deer and stag (15.7%), 9 from old moldy fodder and wildlife feeding grounds (27.2%), and 8 from birds (17.3%). The highest number of isolates was obtained from uncultivated fields. The beta-hemolytic serovars 1/2b and 4b were predominant; other serovars (some of them identified for the first time), including nonhemolyzing strains, have been encountered frequently. It is suggested that
Listeria monocytogenes
is a saprophytic organism which lives in a plant-soil environment and therefore can be contracted by humans and animals via many possible routes from many sources.
Comparative Studies on Microbial and Chemical Modifications of Trichothecene Mycotoxins
Authors: Yoshizawa Takumi , Morooka Nobuichi
Published: December 2020

The microbial modification of several trichothecene mycotoxins by trichothecene-producing strains of
Fusarium nivale
and
F. solani
was studied. These results were compared with the corresponding chemical modifications. The growing mycelia of
Fusarium
spp. did not convert 4β-acetoxy-3α,7α,15-trihydroxy-12,13-epoxytrichothec-9-en-8-one (fusarenon) into 3α,4β,7α,15-tetrahydroxy-12,13-epoxy-trichothec-9-en-8-one (nivalenol), whereas 3α,4β,7α,15-tetraacetoxy-12,13-epoxytrichothec-9-en-8-one (tetraacetylnivalenol) was deacetylated to yield 3α-hydroxy-4β,7α,15-triacetoxy-12,13-epoxytrichothec-9-en-8-one (4,7,15-triacetylnivalenol), which was resistant to further deacetylation. T-2 toxin was transformed into HT-2 toxin, and 8α-(3-methylbutyryloxy)-3α,4β,-15-triacetoxy-12,13-epoxytrichothec-9-en-8-one (T-2 acetate) was transformed into HT-2 toxin via T-2 toxin. Chemical modification with ammonium hydroxide converted tetraacetylnivalenol into fusarenon via 4,7,15-triacetylnivalenol. 3α,-7α,15-Triacetoxy-12, 13-epoxytrichothec-9-en-8-one (triacetyldeoxynivalenol) gave deacetylation products lacking the C-7 or C-15 acetyl group in addition to 7α,15 - diacetoxy - 3α - hydroxy - 12,13 - epoxytrichothec - 9 - en - 8 - one (7,15 - diacetyldeoxynivalenol). These results demonstrate the regio-selectivity in microbial modification of trichothecenes. Based on the results and available knowledge concerning the transformation of trichothecenes, mechanisms for biological modifications of these mycotoxins are postulated.
Role of Bacteria in Bioaccumulation of Mercury in the Oyster
Crassostrea virginica
Authors: Sayler G. S. , Nelson J. D. , Colwell R. R.
Published: December 2020

An investigation of mercury-resistant bacteria was undertaken to determine their role in the accumulation of mercury in a simplified food chain. Oysters (
Crassostrea virginica
) were maintained in a closed system, sealed aquarium with stirred, aerated water containing 10 μg of
203
HgCl
2
per liter. Uptake of
203
Hg by oysters held under control conditions was compared with that of
203
Hg uptake by oysters under similar conditions except that mercury-accumulating and mercury-metabolizing species of
Pseudomonas
, isolated from Chesapeake Bay, were added to the experimental oysters. After incubation for 4 days, the major portion of the
203
Hg in the water column was found to be associated with the microparticulate fraction, corresponding to a rise in total viable count. Mercury accumulation in the oysters was significantly higher in the gill and visceral tissue than other tissues. Mercury concentrations were 200 times greater in tissue fractions of oysters dosed with mercury-metabolizing bacteria compared with the oysters held under control conditions without mercury-metabolizing bacteria.
Application of the Deoxyribonucleic Acid/Ribonucleic Acid Hybridization Technique in
Bdellovibrio
as a Model for Studying Ribonucleic Acid Turnover in Host-Parasite Systems
Authors: Engelking H. Mark , Seidler Ramon J.
Published: December 2020

The kinetics of host ribonucleic acid (RNA) degradation and its resynthesis into
Bdellovibrio
-specific polyribonucleotides has been studied. The kinetics of RNA turnover was followed during a one-step synchronous growth cycle of
Bdellovibrio
growing within
32
PO
4
-labeled
Escherichia coli
host cells. The species of labeled RNA present at any given time was ascertained through the specificity of the deoxyribonucleic acid (DNA)/RNA hybridization technique. At nearsaturating levels of RNA and at zero time, 7% of the host DNA sequences and only 0.04% of the
Bdellovibrio
DNA became hybridized with
32
P-labeled host cell RNA (greater than 99% host specific). At the end of the burst, 98% of the labeled RNA sequences were specific for
Bdellovibrio
DNA. About 74% of the initial labeled host cell RNA became turned over into
Bdellovibrio
-specific sequences. We provide data indicating that host cell ribosomal RNA is assimilated by
Bdellovibrio
. Degradation of host cell RNA occurs in a gradual fashion over most of the
Bdellovibrio
developmental growth cycle. This application of the DNA/RNA hybridization technique and its general concept should be of value in elucidating the kinetics of nucleic acid turnover in other types of host-parasite systems.
Isolation and Some Properties of Glucoamylase from
Cephalosporium charticola
Lindau
Authors: Krzechowska Maria , Urbanek Henryk
Published: December 2020

High glucoamylase (α-D-/1 → 4/glucan glucohydrolase, EC 3.2.1.3.) activity was obtained in the cell-free culture fluid of
Cephalosporium charticola
. Glucoamylase seems to be the only amylolytic enzyme produced by
C. charticola
. The enzyme, purified on diethylaminoethyl-cellulose, was homogeneous by disc gel electrophoresis. The optimum pH on starch was 5.4, and optimum temperature was 60 C. Starch was degraded more rapidly than several other substrates; maltose was hydrolyzed about one-fifth as rapidly as starch. The molecular weight was 69,000, as determined by Sephadex G-100 filtration. The enzyme is a glycoprotein and contains about 6.6% sugars (mannose and glucosamine).
Antigenic Differences Between Infective and Noninfective Strains of
Rhizobium trifolii
Authors: Dazzo Frank B. , Hubbell David H.
Published: December 2020

Immunodiffusion and immunoelectrophoresis techniques have revealed the presence of soluble antigens in sonicated preparations of four infective strains of
Rhizobium trifolii
which were absent in similar preparations of related noninfective mutants derived from the infective strains. The soluble antigens unique to the infective strains were cross-reactive with one another.
Comparative Effects of Anesthetics on the Viability and Integrity of
Escherichia coli
ML30
Authors: Prior B. A. , Fennema O. , Marth E. H.
Published: December 2020

Cells of
Escherichia coli
ML30 in a mineral salts medium were exposed to dichlorodifluoromethane (f-12), cyclopropane, halothane, or Ethrane at concentrations of 1.25, 0.2, 0.04, and 0.008× saturation for times up to 1,200 min, and at temperatures in the range of 2 to 37 C. When any of these anesthetics were applied for 300 min at 1.25× saturation, a substantial decrease in number of survivors occurred. Halothane was most bactericidal, cyclopropane and Ethrane were moderately bactericidal, and f-12 was least bactericidal. At saturation values of less than 1.0, none of the four anesthetics had an appreciable effect on viability of
E. coli
. Greatest increases in cell permeability occurred when anesthetics were used at saturation values of 1.25, and permeability changes generally decreased as the concentrations of the chemicals were reduced. In many instances, anesthetics in the vapor state caused significant increases in cell permeability but little or no loss of viability. This indicated that a close relationship did not exist between loss of viability and increased permeability. All four anesthetics caused
E. coli
to lose substantial and similar amounts of compounds absorbing at 260 nm. Release of compounds absorbing at 260 nm generally increased as the saturation value of a given chemical was increased. Halothane, Ethrane, and cyclopropane but not f-12 caused lysis of
E. coli
ML30. Considering all results,
E. coli
ML30 was damaged more by halothane or cyclopropane than by f-12 or Ethrane. When f-12 was applied at a saturation value of 1.25, the bactericidal effect on
E. coli
was much greater at 37 or 22 C than at 12 or 2 C.
Neutral Lipids and Phospholipids of Free-Living and Bacteroid Forms of Two Strains of
Rhizobium
Infective on
Lotus pedunculatus
Authors: Gerson T. , Patel J. J.
Published: December 2020

The neutral lipids and phospholipids of two strains of rhizobia in their free-living state and in symbiosis with a host plant are described. The principal lipid classes found were the polymer poly-β-hydroxybutyrate, phospholipids, free fatty acids, glycerides, methyl esters, aliphatic alcohols, and hydrocarbons. The lipids include unusual unsaturated methyl-branched and saturated methoxy-branched fatty acids. Most components were found to be common to both forms of both strains, although the proportions varied. A number of strain differences could be discerned.
Aspergillus flavus
Infection and Aflatoxin Production in Fig Fruits
Authors: Buchanan J. R. , Sommer N. F. , Fortlage R. J.
Published: December 2020

Immature fig fruits did not support colonization and aflatoxin production by
Aspergillus flavus
Lk. but became susceptible when ripe. While sun-drying on the tree, fruits were particularly vulnerable to fungal infection and colonization. Aflatoxin accumulation equaled levels frequently reported for such seeds as peanuts and cereal grains.
Derivation of High Enterotoxin B-Producing Mutants of
Staphylococcus aureus
from the Parent Strains
Authors: Altenbern Robert A.
Published: December 2020

Certain pH-sensitive (membrane) mutants of
Staphylococcus aureus
, strains 14458 and 778, produce significantly more type-B enterotoxin (SEB) than the parent type. Some carbohydrate mutants (
car
) from these parent strains also are superior to the parent in SEB formation. By isolating
car
mutants from high-SEB-producing membrane mutants, it is possible to derive a double mutant producing from six to 50 times as much SEB as the parent type. Inversion of the sequence by isolating pH-sensitive mutants from
car
mutants does not yield clones with strikingly higher SEB production than the parent strain. The successful isolation sequence (pH-sensitive mutant first and
car
mutants derived from it) is relatively simple and virtually assures detection of a truly high-SEB-producing clone. The total number of clones whose direct assay for SEB formation is necessary for detection of a high-producing mutant is on the order of 50 to 60.
Influence of Substrate Wettability on the Attachment of Marine Bacteria to Various Surfaces
Authors: Dexter S. C. , Sullivan J. D. , Williams J. , Watson S. W.
Published: December 2020

The effect of the initial substrate surface condition, as indicated by the critical surface tension for wetting, on the rate of attachment of marine bacteria to a variety of solid surfaces has been measured. The techniques used to determine the number of bacteria attached per unit surface area were a lipopolysaccharide test utilizing
Limulus
lysate and direct examination of the surface by scanning electron microscopy. The results obtained by the two techniques are compared and their significance to the control of microbiological slime film formation (microfouling) is discussed.
Inhibition of
Clostridium botulinum
by Strains of
Clostridium perfringens
Isolated from Soil
Authors: Smith Louis Ds.
Published: December 2020

Thirty-one soil samples were examined for the presence of organisms capable of inhibiting growth and toxin production of strains of
Clostridium botulinum
type A. Such organisms were found in eight samples of soil. Inhibiting strains of
C. perfringens
were found in five samples, of
C. sporogenes
in three and of
Bacillus cereus
in three. Three of the
C. perfringens
strains produced an inhibitor effective on all 11 strains of
C. botulinum
type A against which they were tested, seven of eight proteolytic type B strains, one nonproteolytic type B strain, five of nine type E strains and all seven type F strains, whether proteolytic or nonproteolytic. They did not inhibit any of 26 type C strains, 6 type D strains, 4 type E strains, or 24
C. sporogenes
strains. In mixed culture, an inhibitor strain of
C. perfringens
repressed growth and toxin production by a
C. botulinum
type A strain even though it was outnumbered by the latter about 40 times. It also repressed growth and toxin production of
C. botulinum
in mixed culture of soils in which this latter organism naturally occurred when cooked meat medium but not when trypticase medium was used.
Estimate of the Genome Size by Renaturation Studies in
Streptomyces
Authors: Benigni Romualdo , Petrov Peter Antonov , Carere Angelo
Published: December 2020

The genome sizes of
Streptomyces coelicolor
and
Streptomyces rimosus
as calculated by deoxyribonucleic acid reassociation kinetics are approximately 10.5 × 10
6
nucleotide pairs.
Microbial Degradation of Ethylenediaminetetraacetate in Soils and Sediments
Authors: Tiedje James M.
Published: December 2020

[
14
C]ethylenediaminetetraacetate (EDTA) was shown to be slowly biodegraded to
14
CO
2
in soils and sediments under aerobic conditions and by microorganisms in mixed liquid culture. EDTA chelates of Cu, Cd, Zn, Mn, Ca, and Fe added to soil were equally degraded, while Ni-EDTA was degraded more slowly.
Influence of Wine Composition on the Heat Resistance of Potential Spoilage Organisms
Authors: Splittstoesser D. F. , Lienk Laura Lee , Wilkison Martha , Stamer J. R.
Published: December 2020

Pasteurization studies were conducted on 29 yeasts and five lactic acid bacteria. In general the yeasts were more heat resistant in wine than were the bacteria. The one exception was a strain of
Lactobacillus fructivorans
that gave an average D-value of 1.7 min at 60 C. Alcohol was the wine constituent that had the greatest effect on resistance; D-values for all test species were inversely related to the ethanol concentration. The response of organisms to other factors such as pH, sugar, and sulfur dioxide varied with the species.
Formation of Methyl Mercury by Bacteria
Authors: Hamdy M. K. , Noyes O. R.
Published: December 2020

Twenty-three Hg
2+
resistant cultures were isolated from sediment of the Savannah River in Georgia; of these, 14 were gram-negative short rods belonging to the genera
Escherichia
and
Enterobacter
, six were gram-positive cocci (three
Staphylococcus
sp. and three
Streptococcus
sp.) and three were
Bacillus
sp. All the
Escherichia, Enterobacter
, and the
Bacillus
strain were more resistant to Hg
2+
than the strains of staphylococci and streptococci. Adaptation using serial dilutions and concentration gradient agar plate techniques showed that it was possible to select a Hg
2+
-resistant strain from a parent culture identified as
Enterobacter aerogenes
. This culture resisted 1,200 μg of Hg
2+
per ml of medium and produced methyl mercury from HgCl
2
, but was unable to convert Hg
2+
to volatile elemental mercury (Hg
0
). Under constant aeration (i.e., submerged culture), slightly more methyl mercury was formed than in the absence of aeration. Production of methyl mercury was cyclic in nature and slightly decreased if DL-homocysteine was present in media, but increased with methyl-cobalamine. It is concluded that the bacterial production of methyl mercury may be a means of resistance and detoxification against mercurials in which inorganic Hg
2+
is converted to organic form and secreted into the environment.
Concentration of Rous Sarcoma Virus from Tissue Culture Fluids with Polyethylene Glycol
Authors: Bronson D. L. , Elliott A. Y. , Ritzi D.
Published: December 2020

Concentration of Rous sarcoma virus from tissue culture fluids with polyethylene glycol, with and without NaCl or dextran sulfate, resulted in significant and highly variable losses caused by entrapment of virus particles in proteinaceous debris. Treatment of concentrated preparations with Pronase greatly enhanced the recovery of virions. Maximum recovery of virus particles was obtained by the addition of 8% polyethylene glycol and 0.4 M NaCl to tissue culture fluids, followed by Pronase treatment of the concentrated virus preparations.
Detection of Mannitol Formation by Bacteria
Authors: Chalfan Y. , Levy R. , Mateles R. I.
Published: December 2020

A test is described by means of which formation of mannitol from fructose by lactic acid bacteria can be readily detected. The test is based on removal of interference of residual fructose by dehydration with hydrochloric acid followed by thin-layer chromatography.
Mechanism of Benzoic Acid Uptake by
Saccharomyces cerevisiae
Authors: Macris Basil J.
Published: December 2020

A fast uptake of the preservative benzoic acid was observed in
Saccharomyces cerevisiae
, reaching saturation in about two min and then remaining constant at this level. The strong dependence of benzoic acid uptake on pH was due to the relative distribution of molecular and ionic forms in solution and not to the pH itself. The molecular form was the only one taken up by the cells. The specificity of the uptake mechanism was evidenced by the pattern of irreversible heat inactivation of the uptake system resembling protein denaturation by heat. Furthermore, the effect of temperature on the uptake was similar to that observed in enzymic reactions, whereas the kinetic data of uptake conformed to the Michaelis-Menten curve of saturation with a

K
m

of 1.54 × 10
-2
M and

V
max

of 3 × 10
-3
M/10s. The evidence presented in this paper indicates that compounds of protein nature are involved in the uptake of this preservative.
Double-Antibody Radioimmunoassay for Staphylococcal Enterotoxin C
2
Authors: Robern H. , Dighton M. , Yano Y. , Dickie N.
Published: December 2020

A sensitive double-antibody radioimmunoassay for staphylococcal enterotoxin C
2
is described. The assay procedure employs anti-rabbit gamma globulin, prepared in goats, to precipitate the antigen-antibody complex of enterotoxin C
2
and anti-enterotoxin C
2
. The test is sensitive to 100 pg of enterotoxin.
Toxigenic
Aspergillus
and
Penicillium
Isolates from Weevil-Damaged Chestnuts
Authors: Wells John M. , Payne Jerry A.
Published: December 2020

Aspergillus
and
Penicillium
were among the most common genera of fungi isolated on malt-salt agar from weevil-damaged Chinese chestnut kernels (16.8 and 40.7% occurrence, respectively). Chloroform extracts of 21 of 50
Aspergillus
isolates and 18 of 50 representative
Penicillium
isolates, grown for 4 weeks at 21.1 C on artificial medium, were toxic to day-old cockerels. Twelve of the toxic
Aspergillus
isolates were identified as
A. wentii
, eight as
A. flavus
, and one as
A. flavus
var.
columnaris
. Nine of the toxic
Penicillium
isolates were identified as
P. terrestre
, three as
P. steckii
, two each as
P. citrinum
and
P. funiculosum
, and one each as
P. herquei
(Series) and
P. roqueforti
(Series). Acute diarrhea was associated with the toxicity of
A. wentii
and muscular tremors with the toxicity of
P. terrestre
, one isolate of
P. steckii
, and one of
P. funiculosum
.
Psychrophilic Microorganisms from Areas Associated with the Viking Spacecraft
Authors: Foster Terry L. , Winans Luther
Published: December 2020

Microorganisms capable of growth at 7 C were enumerated and isolated from soil samples from the manufacture and assembly areas of the Viking spacecraft. Populations ranging from 4.2 × 10
3
to 7.7 × 10
6
/g of soil were isolated from the 15 soil samples examined. Temperature requirements were determined, and those growing at 3 C, but not at 32 C, were designated as obligate psychrophiles in this investigation. Populations of soil bacteria, including aerobic sporeformers, ranging from 1.5 × 10
2
to 9.8 × 10
5
/g were capable of growth at 3 C, but not at 32 C. Bacterial isolates were identified to major generic groups. No psychrophilic sporeformers were isolated from soil from the manufacture area, but psychrophilic sporeformers ranged from 0 to 6.1 × 10
3
/g from soil from the assembly area.
Evaluation of a Semiautomated System for Direct Fluorescent Antibody Detection of Salmonellae
Authors: Thomason Berenice M. , Hebert G. Ann , Cherry William B.
Published: December 2020

A semi-automatic system under development by Aerojet Medical and Biological Systems for the direct fluorescent antibody detection of salmonellae was evaluated with various food, feed, and environmental samples. All samples were simultaneously examined by Automated Bioassay System (ABS), manual direct fluorescent antibody procedures and cultural procedures. The ABS gave satisfactory results with the processed samples. It detected all of the culturally positive powdered egg and candy samples with no false negative results and gave only 6.6 and 5.3% false positive rates, respectively. With meatmeal samples the ABS failed to detect one culturally positive specimen that was also positive by manual fluorescent antibody and gave one (1.1%) false-positive result. A high rate of false-negative results was obtained by ABS on unprocessed samples of creek water, poultry, and sausage. Adding another enrichment step to the protocol reduced the false-negative rate considerably but severely increased the false-positive rate. The instruments worked reasonably well, but research is needed to improve enrichment procedures for samples to be processed by the system.
Production of Sterigmatocystin by Some Species of the Genus
Aspergillus
and Its Toxicity to Chicken Embryos
Authors: Schroeder H. W. , Kelton W. H.
Published: December 2020

Sterigmatocystin was produced by 59% of
Aspergillus flavus
cultures and by 16% of
A. parasiticus
cultures. All sterigmatocystin-producing cultures of the
A. flavus
group also simultaneously produced aflatoxin or
O
-methylsterigmatocystin. Sterigmatocystin was produced by
A. chevalieri, A. ruber
, and
A. amstelodami
, species not previously reported to produce the compound. In 5-day-old chicken embryos, the no-effect level of toxicity of sterigmatocystin was between 1 and 2 μg/egg; the mean lethal dose was 5 to 7 μg; and 90 to 100% of the embryos were killed with 10 μg. Teratogenic effects and weight reduction were generally associated with nonlethal doses.
Methane Production in Shallow-Water, Tropical Marine Sediments
Authors: Oremland Ronald S.
Published: December 2020

The in situ production of methane was monitored in several types of tropical benthic communities. A bed of
Thalassia testudinum
located in Caesar Creek (Florida Keys) exhibited the highest methanogenic activity (initial rates = 1.81 to 1.86 μmol CH
4
/m
2
per h) as compared with another seagrass (
Syringodium
sp., 0.15 to 0.33 μmol/m
2
per h) and two coral reef environments (Hydro-Lab, 0.016 to 0.10 μmol/m
2
per h; Curaçao, 0.14 to 0.47 μmol/m
2
per h). The results suggest that a wide variety of benthic metabolic processes (e.g., photosynthetic oxygen production) influences methane production rates.
Effect of Microflora on the Free Amino Acid Distribution in Various Regions of the Mouse Gastrointestinal Tract
Authors: Whitt Dixie D. , Demoss R. D.
Published: December 2020

The distribution of free amino acids in the contents of various regions of the gastrointestinal tract (stomach, upper small intestine, lower small intestine, cecum, upper colon and lower colon) was studied in germfree and conventionalized mice. Particular emphasis was placed on the conversion of tryptophan to indole as a probe for studying intermicrobial interactions and microbe-host interactions in vivo. Great differences were observed in the free amino acid content of the various regions of the digestive tract in each type of mouse and also in any one region between germfree and conventionalized mice. As would be expected, there were fewer differences in amino acid distribution between the types of mice in both regions of the small intestine. This correlates with a much lower population of microorganisms in these regions. The changes in free amino acid content and distribution produced by microflora are great enough to serve as a good probe for studying the interactions of a limited number of species of microbes in gnotobiotic animals and assign possible specific functions to each species.
Evaluation of Excitation Light Sources for Incident Immunofluorescence Microscopy
Authors: Thomson L. A. , Hageage G. J.
Published: December 2020

A variety of fluorescent excitation light sources were compared using a standard fluorescein solution or a bacterial conjugate with immunofluorescent microscopy. Quantitative data were obtained with microscope photometric apparatus. Both the quantitative data and comparative conjugate titering suggest that the 450-W xenon arc excited significantly more fluorescence than did the more commonly used 250-W mercury arc or the 100-W halogen lamp. The conjugate could be diluted 4 to 32 times more using the 450-W xenon. Additional advantages of 450-W xenon excitation include sufficient energy of wavelengths between 470 to 490 mm, thus permitting narrow-band excitation resulting in less autofluorescence and the ability to perform fluorescent-antibody procedures without the darkening of ambient room light.
Heterotrophic Activity of Deep-Sea Sediment Bacteria
Authors: Schwarz J. R. , Colwell R. R.
Published: December 2020

Sediment samples, containing mixed microbial populations that were decompressed during retrieval from 7,750 and 8,130 m in the Puerto Rican Trench, were recompressed and incubated at the approximate in situ temperature (3 C) and pressure (775 or 815 atm) in the presence of
14
C-labeled amino acids. Heterotrophic activity (total uptake, CO
2
respiration, and cellular assimilation) and cellular-associated “pool” concentrations were measured. Compared with atmospheric controls held at 3 C, the total uptake at elevated pressure at 3 C was reduced, on an average, 55 times, CO
2
respiration was reduced 45 times, and cellular assimilation was reduced 69 times. Rate of total uptake at elevated pressure was found to range from 4.0 × 10
-11
μg/cell per h for leucine to 2.61 × 10
-10
μg/cell per h for an amino acid mixture. Also, the percentage of total uptake at elevated pressures, respired as CO
2
, increased at the expense of cellular assimilation (ca. 22% increase). Two cellular-associated amino acid pools were detected, a large, loosely bound, outer pool and a small, tightly bound internal pool. The loosely bound outer pool was removed by a change in the pH of the incubation medium. Even though heterotrophic uptake and the outer, cellular-associated pool were markedly reduced at an elevated pressure, the percentage of total uptake calculated for the unincorporated, tightly bound, intracellular pool was 2 to 19 times that obtained for cultures held at 1 atm. The results were interpreted as indicating that bacterial metabolism and biosynthesis in the deep sea are markedly reduced, with a greater proportion of metabolic activity devoted to cellular maintenance.
Autoradiography and Immunofluorescence Combined for Autecological Study of Single Cell Activity with
Nitrobacter
as a Model System
Authors: Fliermans C. B. , Schmidt E. L.
Published: December 2020

Specific detection of a particular bacterium by immunofluorescence was combined with estimation of its metabolic activity by autoradiography. The nitrifying bacteria
Nitrobacter agilis
and
N. winogradskyi
were used as a model system.
Nitrobacter
were incubated with NaH
14
CO
3
and
14
CO
2
prior to study. The same preparations made for autoradiograms were stained with fluorescent antibodies specific for the
Nitrobacter
species. Examination by epifluorescence and transmitted dark-field microscopy revealed
Nitrobacter
cells with and without associated silver grains. Direct detection and simultaneous evaluation of metabolic activity of
Nitrobacter
was demonstrated in pure cultures, in a simple mixed culture, and in a natural soil.
Effect of Incubation Conditions at 55 C on Moisture Loss from Agar Plates
Authors: O'Toole D. K.
Published: December 2020

The percentage of moisture loss was least from plates incubated in plastic bags, sealed jars, or in a humid chamber. There was a stacking effect noted in plates incubated in plastic bags and sealed jars.
Specificity of
Ustilago maydis
Killer Proteins
Authors: Koltin Y. , Day P. R.
Published: December 2020

Bacteria and fungi were tested for sensitivity to
Ustilago maydis
killer strains carrying virus-like particles. Various species taxonomically related to
U. maydis
were sensitive.
Influence of Coliform Source on Evaluation of Membrane Filters
Authors: Brodsky M. H. , Schiemann D. A.
Published: December 2020

Four brands of membrane filters were examined for total and fecal coliform recovery performance by two experimental approaches. Using diluted EC broth cultures of water samples, Johns-Manville filters were superior to Sartorius filters for fecal coliform but equivalent for total coliform recovery. Using river water samples, Johns-Manville filters were superior to Sartorius filters for total coliform but equivalent for fecal coliform recovery. No differences were observed between Johns-Manville and Millipore or Millipore and Sartorius filters for total or fecal coliform recoveries using either approach, nor was any difference observed between Millipore and Gelman filters for fecal coliform recovery from river water samples. These results indicate that the source of the coliform bacteria has an important influence on the conclusions of membrane filter evaluation studies.
Purification and Properties of Intracellular Proteinase from
Streptococcus cremoris
Authors: Ohmiya Kunio , Sato Yasushi
Published: December 2020

Proteolytic activity in the extract from the cells of
Streptococcus cremoris
increased in the presence of casein, lactose, glucose, and CaCl
2
in the media but was negligibly detectable in the extract of the cells harvested from the culture containing succinate or citrate. The intracellular proteinase from
S. cremoris
harvested from tomato medium was purified 150-fold in this experiment. The enzyme had a molecular weight of 140,000, optimum pH at 6.5 to 7.0, and maximum activity at 30 C. The proteinase was activated by Ca
2+
and inhibited by Zn
2+
, Cu
2+
, Hg
2+
, Fe
2+
, ethylenediaminetetraacetate, and sodium lauryl sulfate. The

K
m

value of the enzyme towards each casein fraction was almost the same, and the

V
max

of the enzyme towards α
s
-casein was smaller than those towards the other casein fractions.
Influence of pH on the Heat Inactivation of Staphylococcal Enterotoxin A as Determined by Monkey Feeding and Serological Assay
Authors: Humber John Y. , Denny Cleve B. , Bohrer C. Wallace
Published: December 2020

The effect of pH on the thermal inactivation of staphylococcal enterotoxin A was investigated. Analysis of heated toxin by immunodiffusion in gel indicated that enterotoxin A in beef bouillon was inactivated faster at pH 5.3 than at pH 6.2. The
z
values (slopes) for the heat inactivation curves at pH 6.2 and 5.3 were 49.5 and 55 F (about 27 and 30 C), respectively. Enterotoxin produced and heated in dialyzed Casamino Acids medium and assayed by monkey feeding was more easily inactivated by heat at pH 5.3 than at pH 7.8. Thermal inactivation curves for enterotoxin A in beef bouillon (5 μg/ml, pH 5.3) were determined by two methods, monkey feeding and serological assay. The
z
values for the curves obtained by these two methods were both 55 F, although loss of biological or toxic activity of the enterotoxin occurred before loss of serological activity.
Survival of Salmonellae During Pepperoni Manufacture
Authors: Smith James L. , Huhtanen Charles N. , Kissinger John C. , Palumbo Samuel A.
Published: December 2020

Survival of salmonellae in artificially contaminated beef-pork mixtures (approximately 10
4
salmonellae/g) was studied in pepperoni prepared by either a natural flora or lactic starter culture fermentation or in nonfermented sausages. The pepperoni did not become salmonellae free during the usual commercial 15 to 30-day drying period.
Salmonella dublin
was present in all products, fermented or unfermented, after 42 to 43 days of drying. At a lower level of contamination, 10
3
/g,
S. dublin
could not be recovered from started culture fermented pepperoni after 14 days of drying but persisted in the natural florafermented sausage.
S. typhimurium
(initial count, 10
4
/g) was absent after 42 days of drying when starter culture was used to ferment the pepperoni, but was still present in the natural flora-fermented and unfermented products.
S. dublin
, host adapted to cattle, or
S. choleraesuis
, host adapted to swine, had similar survival patterns in beef, pork, or beef-pork pepperoni. Heating salmonellaecontaminated beef-pork pepperoni (after fermentation but before drying) to an internal temperature of 60 C (trichinae inactivating) eliminated the food-borne pathogen from the sausage product.
Treatment of
Salmonella-Arizona
-Infected Turtle Eggs with Terramycin and Chloromycetin by the Temperature Differential Egg Dip Method
Authors: Siebeling R. J. , Neal Philip M. , Granberry W. David
Published: December 2020

Attempts to eliminate
Salmonella
and
Arizona
infection from newly hatched turtles were made by dipping fresh eggs in cold solutions of Terramycin and Chloromycetin at 1,000, 1,200, 1,500 and 2,000 μg per ml for either 10, 20, or 30 min. Control groups consisted of hatchlings produced from nondipped eggs or eggs dipped in chilled water. In two of the four experiments 5 to 10 eggs were blended on days 15, 30, and 45 post antibiotic dip treatment. Twenty-five to 60 hatchlings from each control or experimental dip group were held in containers and the water was tested (excretion method) for
Salmonella
and
Arizona
every 15 or 30 days for 180 to 210 days after hatching. Representative turtles were homogenized (blending method) to determine if systemic infections were present. All specimens tested were enriched in tetrathionate and selenite cystine broth. Nondipped eggs and water-dipped eggs routinely showed
Salmonella
and
Arizona
present in egg homogenate and hatchlings emerging from these eggs excreted these pathogens. Terramycin- and Chloromycetin-dipped eggs were uniformly negative for these pathogens, only if fresh eggs were dipped. Bacteriological assay of container water and whole turtle homogenate from hatchlings were negative for
Salmonella
and
Arizona
if eggs were dipped in 1,000 μg of Terramycin early in the egg laying season or if eggs were dipped in 1,500 or 2,000 μg of Terramycin per ml late in the egg laying season. The results of temperature-differential egg dip studies suggest that this is a feasible and promising method by which to eradicate
Salmonella
and
Arizona
from the turtle.