bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Carbohydrates on Growth and Sporulation of
Clostridium perfringens
Type A
Authors: Labbe Ronald G. , Duncan Charles L.
Published: December 2020

Growth and sporulation of
Clostridium perfringens
type A in Duncan and Strong (DS) sporulation medium was investigated. A biphasic growth response was found to be dependent on starch concentration. Maximal levels of heat-resistant spores were formed at a starch concentration of 0.40%. Addition of glucose, maltose, or maltotriose to a sporulating culture resulted in an immediate turbidity increase, indicating that biphasic growth in DS medium may be due to such starch degradation products. Amylose and, to a lesser extent, amylopectin resulted in biphasic growth when each replaced starch in the sporulation medium. A level of heat-resistant spores approximately equal to the control was produced with amylopectin but not amylose as the added carbohydrate. Addition of glucose or maltose to a DS medium without starch at stage II or III of sporulation did not alter the level of heat-resistant spores as compared with the level obtained in DS medium with starch. Omission of starch or glucose or maltose resulted in an approximately 100-fold decrease in the number of heat-resistant spores, although the percentage of sporulation (90%) was unaffected. The role of starch and amylopectin in the formation of heat-resistant spores probably involves the amylolytic production of utilizable short-chain glucose polymers that provides an energy source for the completion of sporulation.
Effect of Relative Humidity on the Survival of Airborne Unicellular Algae
Authors: Ehresmann Douglas W. , Hatch Melvin T.
Published: December 2020

A method is described which is suitable for assessing the effects of relative humidity (RH) on the viability of two unicellular algae in experimental aerosols. Viable cells of
Nannochloris atomus
collected from the airborne state were detected by plating onto agar surfaces of an appropriate growth medium, whereas viable airborne cells of
Synechococcus
sp., because of unreliable growth on solid media, were determined by a liquid assay system. The assays were performed at intervals during short-term and prolonged storage of algal aerosols in chambers preconditioned to a selected RH and temperature. Both species showed the greatest loss in viability during the first minute after atomization, and the extent of this inactivation, as a function of RH, reflected the subsequent long-term survival. The airborne eukaryotic alga was unable to survive at an RH below 91%, whereas the airborne prokaryotic alga was comparatively stable over a wide humidity range. Initial inactivation was least and long-term survival best, for both species, at 94% RH.
Oxidative Degradation of Squalene by
Arthrobacter
Species
Authors: Yamada Yasuhiro , Motoi Hirobumi , Kinoshita Shinichi , Takada Nobuo , Okada Hirosuke
Published: December 2020

An organism isolated from soil and identified as
Arthrobacter
sp. was studied for its squalene degradation. The degradation product from squalene, which accumulated in the culture broth, was isolated and identified as trans-geranylacetone by mass spectrometry, gas chromatography, infrared spectrometry, and nuclear magnetic resonance spectrometry. Addition of a high concentration of K
2
HPO
4
to the culture medium resulted in accumulation of fairly large amounts of carboxylic acids in addition to geranylacetone. These carboxylic acids were identified as isovaleric, β,β′-dimethylacrylic, geranic, and (+)-(R)-citronellic acids. Among these acids, α,β-saturated carboxylic acids were found to be predominant in quantity.
Two-Dimensional Polyacrylamide Gel Electrophoresis of Envelope Proteins of
Escherichia coli
Authors: Johnson W. Charles , Silhavy T. J. , Boos W.
Published: December 2020

A method of separating envelope proteins by two-dimensional polyacrylamide gel electrophoresis is described.
Escherichia coli
envelopes (inner and outer membranes) were prepared by French pressing and washed by repeated centrifugation. Membrane proteins were solubilized with guanidine thiocyanate and were dialyzed against urea prior to two-dimensional electrophoretic analysis. The slab gel apparatus and conditions were similar to the technique developed by Metz and Bogorad (1974) for the separation of ribosomal proteins. This separation occurs in 8 M urea for the first dimension and in 0.2% sodium dodecyl sulfate for the second dimension. The technique separates about 70 different membrane proteins in a highly reproducible fashion according to both intrinsic charge and molecular weight. Some examples of alterations in the membrane protein pattern are demonstrated. These alterations are caused by a mutation affecting a sugar transport system and by growth in the presence of D-fucose, inducer of the transport system. A further example of membrane protein changes introduced by growth at the nonpermissive temperature of a temperature-sensitive cell division mutant is shown. Finally, it is demonstrated that the major outer membrane component of
Escherichia coli
K-12 contains more than four proteins of similar molecular weight.
Powdered Chitin Agar as a Selective Medium for Enumeration of Actinomycetes in Water and Soil
Authors: Hsu S. C. , Lockwood J. L.
Published: December 2020

Agar media made with 0.4% colloidal chitin plus mineral salts and adjusted to pH 8.0 was superior to four other commonly used media for the isolation and enumeration of actinomycetes from water samples. More actinomycetes developed on chitin agar, and the development of bacteria and fungi was suppressed. Frozen and vacuum-dried chitin from aqueous colloidal suspensions was finely divided and gave results comparable to those obtained with media prepared from colloidal suspensions.

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Microbial Reduction of 1,3-Dioxo-2-Methyl-2-(3′-Oxo-6′-Carbomethoxyhexyl)-Cyclopentane to Form 1β-Hydroxy-3-Oxo-2β-Methyl-2α-(3′-Oxo-6′-Carbomethoxy-hexyl)-Cyclopentane, an Intermediate for Steroid Total Synthesis
Authors: Lanzilotta Raymond P. , Bradley Dorothy G. , Beard Colin C.
Published: December 2020

The rate and extent of stereoselective reduction of 1,3-dioxo-2-methyl-2-(3′-oxo-6′-carbomethoxyhexyl)-cyclopentane to form the 1β-hydroxy-2β-methyl isomer by cultures of
Schizosaccharomyces pombe
ATCC 2476 was dramatically increased by addition to the fermentation of certain α,β-unsaturated ketones and allyl alcohol.

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Prophage Induction in
Escherichia coli
(Lambda) by
N
-Nitrosamines
Authors: Thomson Jennifer A. , Woods D. R.
Published: December 2020

Carcinogenic
N
-nitrosamines were tested for their ability to induce λ in a lysogenic strain of
Escherichia coli
K-12 (58-161 F
+
). Dimethylnitrosamine, di-
n
-propylnitrosamine, methyl-
n
-propylnitrosamine, and
N
-nitrosopiperidine were shown to be inducers of prophage.
Growth of a Mixed Species Lactic Starter in a Continuous “pH-Stat” Fermentor
Authors: Pettersson H.-E.
Published: December 2020

Optimum growth conditions for mixed species starter FDs 0172 in skim milk, whey medium, and tryptone medium at 25 C in a “pH-stat” continuous fermentor were investigated. Specific growth rate and productivity were found to be influenced both by the medium and the pH value. Highest productivity was found in skim milk medium between pH 5.5 and 5.9. Lactic acid-producing activity of harvested cells decreased by continuous cultivation at pH values lower than 5.9 to 6.1, especially in tryptone and whey medium. Bacterial balance, CO
2
production, and aroma formation were comparable to the control in skim milk and whey medium at any pH, but differed significantly for cells grown in tryptone medium.
Molecular Construction of
Clostridium botulinum
Progenitor Toxin
Authors: Ohishi Iwao , Sakaguchi Genji
Published: December 2020

Molecular dissociation of purified type F progenitor toxin with an
S
20,w
of 10.3 and a molecular weight of 235,000 into two components, toxic and atoxic, was demonstrated by ultracentrifugation, gel filtration, and diethylaminoethyl-Sephadex chromatography at pH 7.5. The ultracentrifugal analysis indicated that type F progenitor toxin dissociates into components of the same molecular size of 5.9
S
. The toxic component contained a toxicity of 2.5 × 10
8
50% lethal doses per mg of N. Much higher stability of progenitor toxin than that of derivative toxin, particularly at pH below 5, suggests that only progenitor toxin can act as an oral toxin.
Stability of Bacterial Mutants in Saline
Authors: Kropinski A. M.
Published: December 2020

By storage in 1% NaCl, genetically characterized strains of
Escherichia coli, Salmonella typhimurium
, and
Pseudomonas aeruginosa
were stable for more than 1 year at 4 C. This method of preservation was more effective than maintenance of the strains in stab culture.
New Method for the Large-Scale Preparation of Diptheria Toxoid: Purification of Toxin
Authors: Cox John C.
Published: December 2020

Diptheria toxin of high purity was prepared in batch cultures of 1 to 40 liters by procedures capable of processing 200-liter batches without modification. The procedure incorporates preliminary purification of the growth medium and, after deep fermentation or surface culture of
Corynebacterium diphtheriae
, both concentration and partial purification of the toxin by membrane ultrafiltration. Final purification is achieved by Sephadex G-100 gel filtration. Purities of 2,000 to 2,500 flocculation units per mg of protein nitrogen (260 to 410 flocculation units per unit of absorbance at 280 nm) were routinely obtained with only a 10% loss of toxin. The toxin appeared pure on immunoelectrophoresis and ultracentrifugation, and only minor amounts of lower-molecular-weight impurities were revealed by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. Significant advantages of the procedure are its rapidity and reproducibility and the fact that all stages are performed at 4 C in neutral isotonic buffer.
Effects of Time and Growth Media on Short-Chain Fatty Acid Production by
Bacteroides fragilis
Authors: Mayhew James W. , Onderdonk Andrew B. , Gorbach Sherwood L.
Published: December 2020

Gas-liquid chromatography was used to monitor the evolution of short chain fatty acids by
Bacteroides fragilis
in five media. Acetic and succinic acids, the prominent end products encountered, were readily detected within 24 h. Propionic, isobutyric, butyric, isovaleric, and lactic acids were usually recorded in more limited quantities. Maximum rates of bacterial multiplication, glucose catabolism, and end-product production coincided with the first 24 h in carbohydrate-supplemented media. Extended incubation (672 h) favored substantial succinate increases in three of five media. These observations suggest that incubation time and composition of the medium are important determinants in short chain fatty acid production by
B. fragilis
.
Rapid Determination of the Amount of Cetylpyridinium Chloride Bound by Bacteria
Authors: Caputo Ross A. , Treick Ronald W. , Griffin Charles C. , Farrell Michael P.
Published: December 2020

A modification of the Colowick and Womack procedure for measuring ligand binding by macromolecules is described for drug binding by bacteria. This technique is based on the determination of drug concentration in the dialysate from a bacteria-drug mixture at equilibrium. The dialysis cell of the original procedure was replaced by a Minibeaker (Bio-Rad), which has a larger membrane surface area, and the dialysate was continuously monitored with a spectrophotometer equipped with a flow cell. With this system, only 3 min was required to determine the amount of cetylpyridinium chloride bound by
Escherichia coli
K-12 strain P678. Possible applications of the technique are discussed.
Interpretation of the Tube Coagulase Test for Identification of
Staphylococcus aureus
Authors: Sperber W.H. , Tatini S.R.
Published: December 2020

The tube coagulase test is a valid means of identifying
Staphylococcus aureus
, provided that only a firm clot that does not move when the tube is tipped is considered a positive reaction. The widely promulgated interpretation that all degrees of clotting in coagulase plasma are a positive identification of
S. aureus
was disproved by the use of other tests such as anaerobic glucose fermentation thermonuclease production, and lysostaphin sensitivity. It was found that the source of supply of the coagulase plasma is a factor in the occurrence of false-positive coagulase test results. The use of pig and rabbit plasma in the tube coagulase test is also discussed.
Regulation of Predation by Prey Density: the Protozoan-
Rhizobium
Relationship
Authors: Danso S. K. A. , Alexander M.
Published: December 2020

Tetramitus rostratus
and strains of
Hartmanella, Naegleria
, and
Vahlkampfia
consumed large numbers of
Rhizobium meliloti
cells in a salt solution, but protozoan multiplication and the bacterial decline stopped when the prey density fell to about 10
6
to 10
7
cells/ml. At higher prey densities, the maximum numbers of
Hartmanella
sp. and
Naegleria
sp. were proportional to the quantity of
R. meliloti
initially provided to the amoebas. When supplemental rhizobia were supplied to
Hartmanella
sp. or
Naegleria
sp. after their active feeding had terminated, presumably because the remaining 10
6
or 10
7
bacteria/ml could not be captured, replication of the protozoa was initiated. The rate of elimination of rhizobia present in large populations was proportional to the initial abundance of
Naegleria
sp., but the final numbers of amoebas and surviving
R. meliloti
cells were independent of initial numbers of predators. The surviving bacteria were not intrinsically resistant to attack because 98% of the survivors, when concentrated, were consumed. It is suggested that large populations of bacteria in nature may be reduced in size by predatory protozoa, but many of the prey cells will not be eliminated.
Preliminary Studies of Fluorescent Pseudomonads Capable of Growth at 41 C in Swimming Pool Waters
Authors: Hoadley A. W. , Ajello Gloria , Masterson Nola
Published: December 2020

During the summer of 1973 cultures of
Pseudomonas aeruginosa
and other fluorescent pseudomonads capable of growth at 41 C were obtained from swimming pool waters at a training center for the mentally retarded. Isolates were subjected to selected physiological tests, pyocine typing, and immunotyping. High counts of
P. aeruginosa
or other fluorescent pseudomonads consisted mainly of single predominant types. Both
P. aeruginosa
strains and unidentified fluorescent
Pseudomonas
strains predominated in pool waters at different times.
Violet Red Bile 2 Agar for Stressed Coliforms
Authors: Hartman Paul A. , Hartman Philip S. , Lanz Wayne W.
Published: December 2020

Counts on a new, autoclave-sterilizable violet red bile (VRB-2) agar were compared with counts on freshly boiled VRB agar. Yields on VRB-2 agar averaged 217, 180, 130, and 112% of counts obtained on the control medium for samples of water, cottage cheese, frozen vegetables, and raw milk, respectively. The general principle used for the development of VRB-2 agar could be applied to many other kinds of selective plating media.
Method for Sampling Meat Surfaces
Authors: Yokoya Fumio , Zulzke Maria Lúcia
Published: December 2020

A new method for sampling meat surfaces was developed. Bacterial counts of beef carcasses by the cotton swab technique and by the new method showed that the latter gave higher counts. These counts were closely correlated with data obtained by using the swab method. Advantages of the new method are its simplicity, rapidity, and adaptability to routine use on any type of carcass.
Toxicity and Occurrence of
Balansia
on Grasses from Toxic Fescue Pastures
Authors: Bacon Charles W. , Porter James K. , Robbins Joe D.
Published: December 2020

Balansia epichloë
(Weese) and
B. henningsiana
(Moell.) were isolated from grasses in toxic fescue pastures.
B. epichloë
, cultured in a synthetic medium, was toxic to chicken embryos. Thin-layer chromatography and ultraviolet absorption data indicated that in submerged culture the fungus produced compounds with the indole or ergoline nucleus.
Inactivation of Enterovirus by Glutaraldehyde
Authors: Saitanu Kriensag , Lund Ebba
Published: December 2020

A study on the rate of inactivation by glutaraldehyde of coxsackievirus was conducted using different concentrations, temperatures, and pH values. It was found, that 2% glutaraldehyde at pH 7.4 and 25 C, as recommended for a sporicide, reduced the titer of infectious virus by 2 log
10
U in 1 min or less. The reduction was not negatively affected by high concentrations of organic matter (serum and animal spillings) in the reaction mixtures.
Taxonomic Study of Fusaria of the Sporotrichiella Used in Recent Toxicological Work
Authors: Joffe A. Z. , Palti J.
Published: December 2020

Eight isolates of
Fusarium
of the Sporotrichiella section were critically studied as to their taxonomic position. Most of these isolates had been used for comprehensive toxicological work on mycotoxin effects on animals, chiefly in the United States and Japan. Isolates NRRL 3299 and NRRL 3287, supplied from the United States, were determined to be
Fusarium poae
. Isolates NRRL 3249, NRRL 5908, 2061-C, and YN-13 from the United States and isolate T-2 from South Africa belonged to
Fusarium sporotrichioides
. Isolate NRRL 3509 belonged to
F. sporotrichioides
var.
tricinctum
. The relevance of recent toxicological work with these isolates on animals to earlier work on alimentary toxic aleukia is discussed in light of the above identifications.
Extracellular Lipids of
Cladosporium
(
Amorphotheca
)
resinae
Growth on Glucose or on
n
-Alkanes
Authors: Siporin C. , Cooney J. J.
Published: December 2020

Cladosporium
(
Amorphotheca
)
resinae
was grown in shake culture on glucose,
n
-dodecane, or
n
-hexadecane. Growth was most rapid on glucose, and more acid accumulated in the medium than in
n
-alkane-grown cultures. Neutral lipid was the major lipid fraction and triglycerides were the only extracellular neutral lipids detected. Dodecanoic (lauric) acid was the predominant fatty acid (>60%) in neutral lipids from all three media, with lesser amounts of tetradecanoic, hexadecanoic, and octadecanoic acids. Extracellular phospholipids identified were phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, and cardiolipin or a cardiolipin-like compound. Phospholipids from all three media contained dodecanoic acid as their principle fatty acid. Dodecanoic acid was the only extracellular free fatty acid detected. Glucose medium contained acetic, glyoxylic, and glycolic acids and an unidentified organic acid which may contribute to the lower pH in cultures after growth on glucose. In all classes of extracellular lipids the fatty acids do not correspond to the fatty acids previously determined to be associated with cellular lipids. Moreover, the fatty acids of extracellular lipids do not reflect the chain length of the
n
-alkane growth substrate.
Isolation and Characterization of
Vibrio parahaemolyticus
from Cape Cod Soft-Shell Clams (
Mya arenaria
)
Authors: Earle Paul M. , Crisley F. D.
Published: December 2020

Vibro parahaemolyticus
was isolated from soft-shell clams (
Mya arenaria
) taken from 10 different clamming areas on Cape Cod, Mass., during July and August 1972. Direct plating on thiosulfate-citrate-bile salts-sucrose agar was found to be superior to either direct plating on Vanderzant modified salt starch agar or enrichment with Trypticase soy broth containing 7% salt for isolation from clam samples. Morphological and biochemical characteristics of 33 isolates from 30 samples generally conform to those described for this organism in the literature, except for the production of acid from sucrose, lactose, and sorbitol. Six of the isolates were hemolytic on human blood agar plates, whereas all showed a negative Kanagawa phenomenon. Twenty of the 33 isolates reacted with pooled antisera to the K antigen; 15 of these reacted with 9 different specific K antisera, leaving 5 untypable. Ten of these 15 reacted with 4 different O antisera.
Egg Production, Shell Thickness, and Other Physiological Parameters of Laying Hens Affected by T-2 Toxin
Authors: Wyatt R. D. , Doerr J. A. , Hamilton P. B. , Burmeister H. R.
Published: December 2020

T-2 toxin has been reported to cause severe oral lesions and neural disturbances in young broiler chickens. T-2 toxin, when added at a level of 20 μg per g of feed, caused oral lesions but no abnormal neural disturbances in young broiler chickens. T-2 toxin, when added at a level of 20 μg per g of feed, caused oral lesions but no abnormal neural symptoms in laying hens. T-2 toxin had no effect on either hemoglobin, hematocrit values, erythrocyte count, plasma glucose, prothrombin times, or the sizes of the liver, spleen, pancreas, and heart. Lipid content of the liver was not altered. Feed consumption, however, was reduced, as were the total plasma protein and lipid concentrations and the total leukocyte count. Most important economically was the lowered egg production and a thinner egg shell. The timing and severity of the symptoms suggest that T-2 toxin causes primary oral lesions that reduce feed consumption with a consequent reduction in serum proteins and lipids, which culminate in decreased egg production. The leucopenia and thinner egg shell may be independent systemic effects of T-2 toxin in laying hens.
Qualitative and Quantitative Assay of Trichothecin: a Mycotoxin Produced by
Trichothecium roseum
Authors: Sorenson W. G. , Sneller M. R. , Larsh H. W.
Published: December 2020

A method for quantitative determination of trichothecin in crude culture filtrates was presented. The method utilized an agar diffusion bioassay against
Candida albicans
, a colorimetric test involving a halochromatic reaction with sulfuric acid, and subsequent formation of blue color with methanol, and thin-layer chromatography of trichothecin and its dinitrophenylhydrazine derivative. A positive result in all three systems confirmed the presence of trichothecin. Quantitative results were generally in close agreement.
Phosphoglycerides of
Trichophyton terrestre
and One Phenotype Selected from the Apollo 16 Microbial Ecology Evaluation Device
Authors: Sawyer R. T. , Deskins D. C. , Volz P. A.
Published: December 2020

Total lipid extracted from wild-type
Trichophyton terrestre
CDC-X285 was found to be 2.0% of the dry cell weight. The total lipid contained the following phospholipid components identified by silicic acid-impregnated thin-layer and paper chromatography: phosphatidyl inositol, phosphatidyl choline, phosphatidyl serine, and phosphatidic acid. The total lipid extracted from the phenotype
T. terrestre
7048-1 isolated from the Apollo 16 Microbial Ecology Evaluation Device (MEED) was found to vary according to the time at which the phospholipids were extracted. The
Trichophyton
phenotype was selected from a cuvette housed in the MEED exposed to specific space parameters including ultraviolet light of known wavelengths and energy levels in deep space. The phospholipid components identified in the phenotype were phosphatidyl ethanolamine and cardiolipin. The major lipid fraction was composed of digalactosyl diglyceride and monogalactosyl diglyceride. An unusual lipid was detected in the phenotype, which appeared to be sterol glycoside.
Faculative Anaerobic Bacteria in the Digestive Tract of Chum Salmon (
Oncorhynchus keta
) Maintained in Fresh Water Under Defined Culture Conditions
Authors: Trust T. J.
Published: December 2020

The bacterial flora in the digestive tract of chum salmon growing in fresh water under defined and controlled culture conditions was examined both qualitatively and quantitatively. The predominant species present in the digestive tract were identified as
Aeromonas
, with
Aeromonas hydrophila
being the most common isolate. These aeromonads were not isolated from the diet. Other bacterial species commonly isolated included
Bacillus, Enterobacter
, nonpigmented pseudomonads,
Micrococcus
, and
Acinetobacter
. These species were also isolated from the diet or tank water. As many as 10
8
viable bacteria per g (wet weight) of digestive tract plus contents were counted. After 75 days of starvation, 10
6
viable bacteria were counted, whereas fish fed a sterile feed contained 10
5
viable bacteria per g (wet weight) of digestive tract plus contents.
Effect of Dichlorodifluoromethane on the Appearance, Viability, and Integrity of
Escherichia coli
Authors: Prior B. A. , Fennema O. , Pate J.
Published: December 2020

Cultures of
Escherichia coli
H52 were treated with liquid dichlorodifluoromethane (fluorocarbon-12 [f-12]) for 2 h at 22 C and then examined microscopically. Treated cells tended to clump, and their cytoplasms were generally less dense and less uniform in appearance than those of control cells.
E. coli
ML30 was exposed to f-12 at a concentration of 1.25 × saturation for times up to 1,200 min at 22 C. Cells were examined for changes in viability (plate count), permeability (as measured by exit of α-[
14
C]methylglucoside or uptake of
o
-nitrophenyl-β-D-galactopyranoside), release of compounds absorbing at 260 nm, and lysis (changes in absorbance at 420 nm). Large losses of α-methylglucoside and of percentage of viability occurred after brief exposure to f-12. Release of compounds absorbing at 260 nm occurred more slowly than the aforementioned events, possibly because these molecules are larger than α-methylglucoside. During 1,200-min exposure to f-12, the number of survivors decreased from 10
9
to 10
4
organisms/ml, the loss of compounds absorbing at 260 nm amounted to 50% and 32% lysis occurred. Most of these changes occurred during the first 300 min of treatment. Loss of α-methylglucoside was almost complete after 1-min exposure to f-12. These results suggest that death of the cell involves several stages, with a change of permeability occurring first, followed by leakage of compounds of increasing size and, finally, lysis.
Rumen Bacterial Degradation of Forage Cell Walls Investigated by Electron Microscopy
Authors: Akin Danny E. , Amos Henry E.
Published: December 2020

The association of rumen bacteria with specific leaf tissues of the forage grass Kentucky-31 tall fescue (
Festuca arundinacea
Schreb.) during in vitro degradation was investigated by transmission and scanning electron microscopy. Examination of degraded leaf cross-sections revealed differential rates of tissue degradation in that the cell walls of the mesophyll and pholem were degraded prior to those of the outer bundle sheath and epidermis. Rumen bacteria appeared to degrade the mesophyll, in some cases, and phloem without prior attachment to the plant cell walls. The degradation of bundle sheath and epidermal cell walls appeared to be preceded by attachment of bacteria to the plant cell wall. Ultrastructural features apparently involved in the adhesion of large cocci to plant cells were observed by transmission and scanning electron microscopy. The physical association between plant and rumen bacterial cells during degradation apparently varies with tissue types. Bacterial attachment, by extracellular features in some microorganisms, is required prior to degradation of the more resistant tissues.
Lysis of
Sphaerotilus natans
Swarm Cells by
Bdellovibrio bacteriovorus
Authors: Venosa Albert D.
Published: December 2020

Six strains of
Sphaerotilus natans
(smooth form) were lysed by five parasitic strains of
Bdellovibrio bacteriovorus
. The possible use of
Bdellovibrio
to control the proliferation of
S. natans
in the environment was hypothesized.
Production of 3-Methyl-6-Methoxy-8-Hydroxy-3,4-Dihydroisocoumarin by
Aspergillus caespitosus
Authors: Schroeder H. W. , Stipanovic R. D.
Published: December 2020

Aspergillus caespitosus
Raper and Thom cultured on autoclaved cracked, yellow field corn produced 3-methyl-6-methoxy-8-hydroxy-3,4-dihydroisocoumarin which was extracted and then purified by silica gel columns. The physical and spectral properties of the colorless crystals from methylene chloride:hexane were consistent with those published for 3-methyl-6-methoxy-8-hydroxy-3,4-dihydroisocoumarin. Yield of high purity 3-methyl-6-methoxy-8-hydroxy-3,4-dihydroisocoumarin was about 140 mg of corn per kg.
Degradation of Benzothiophene and Related Compounds by a Soil
Pseudomonas
in an Oil-Aqueous Environment
Authors: Sagardía Fermín , Rigau Juan J. , Martínez-Lahoz Agnes , Fuentes Francisco , Waldemar Carmen , Flores Waldemar
Published: December 2020

Pseudomonas aeruginosa
PRG-1, an isolate from oil-contaminated soil, degrades benzothiophene (BT) and other related compounds in a 5% oil-basal medium system. The organism cannot grow on BT alone; 0.05% yeast extract is a suitable substrate for its growth and for its attack on BT. Although BT is partially toxic to the bacteria, toxicity is reduced when BT is added in this oil system. The oil phase is emulsified by bacterial action during the process. Oxygen uptake studies with washed cell suspensions show increased respiration in the presence of BT. Endogenous respiration is markedly decreased by
p
-hydroxy-mercuribenzoate, whereas respiration due to BT is scarcely affected, suggesting that oxygen is added directly to BT. Results obtained both in direct degradation and in respiration studies indicate that 3-methyl-thiophene is more rapidly and extensively degraded than BT and other related compounds.
Arylamidase Activity of
Salmonella
Species
Authors: Sheahan J. P. , Eitenmiller R. R. , Carpenter J. A.
Published: December 2020

Arylamidase activity in cell extracts of sonically cell treated suspensions of 23
Salmonella
strains, including 12 strains of
S. typhimurium
, was investigated. All cultures hydrolyzed five of nine different neutral and basic substrates. Activity against aspartyl-, cystyl- histidinyl-, and isoleucyl-β-naphylamide was negligible. Alanyl-β-naphthylamide was the preferred substrate for the
Salmonella
species; however, specific activities ranged widely. Of several gram-negative organisms surveyed, all except
Proteus vulgaris
hydrolyzed alanyl-β-naphthylamide at the fastest rate. The most preferred substrate for the
Proteus
culture was glycyl-β-naphthylamide. No relationship could be shown between virulence and arylamidase activity for the
Salmonella
strains.
Basis for the Resistance of Several Algae to Microbial Decomposition
Authors: Gunnison Douglas , Alexander Martin
Published: December 2020

The basis for the resistance of certain algae to microbial decomposition in natural waters was investigated using
Pediastrum duplex, Staurastrum
sp., and
Fischerella muscicola
as test organisms. Enzyme preparations previously found to convert susceptible algae into spheroplasts had no such effect on the resistant species, although glucose and galacturonic acid were released from
P. duplex
walls. Little protein or lipid but considerable carbohydrate was found in the walls of the refractory organisms, but resistance was not correlated with the presence of a unique sugar monomer. A substance present in
Staurastrum
sp. walls was characterized as lignin or lignin-like on the basis of its extraction characteristics, infrared spectrum, pyrolysis pattern, and content of an aromatic building block. Sporopollenin was found in
P. duplex
, and cellulose in
Staurastrum
sp. Cell walls of the algae were fractionated, and the fractions least susceptible to microbial degradation were the sporopollenin of
P. duplex
, the polyaromatic component of
Staurastrum
sp., and two
F. muscicola
fractions containing several sugar monomers. The sporopollenin content of
P. duplex
, the content of lignin or a related constituent of
Staurastrum
sp., and the resistance of the algae to microbial attack increased with age. It is suggested that resistance results from the presence of sporopollenin in
P. duplex
, a lignin-like material in
Staurastrum
sp., and possibly heteropolysaccharides in
F. muscicola
.
Comparison of the Survival and Metabolic Activity of Psychrophilic and Mesophilic Yeasts Subjected to Freeze-Thaw Stress
Authors: Meyer Edward D. , Sinclair Norval A. , Nagy Bartholomew
Published: December 2020

A mesophilic yeast,
Candida utilis
, and a psychrophilic yeast,
Leucosporidium stokesii
, were subjected to freeze-thaw cycling over the range 25 to -60 C. Viability after freeze-thaw stress was directly correlated with the rate of cooling and the physiological age of the cultures. Rates of glucose fermentation and oxidation could be directly correlated with viability. The optimal cooling rate for both yeast strains was 4.5 to 6.5 C/min; however, their levels of survival obtained at this optimal cooling rate varied considerably. In addition, the psychrophile was less resistant to freeze-thaw stress than was the mesophile.
Properties of D-Xylose Isomerase from
Streptomyces albus
Authors: Sanchez Sergio , Smiley Karl L.
Published: December 2020

A partially purified D-xylose isomerase has been isolated from cells of
Streptomyces albus
NRRL 5778 and some of its properties have been determined. D-Glucose, D-xylose, D-ribose, L-arabinose, and L-rhamnose served as substrates for the enzyme with respective

K
m

values of 86, 93, 350, 153, and 312 mM and

V
max

values measuring 1.23, 2.9, 2.63, 0.153, and 0.048 μmol/min per mg of protein. The hexose D-allose was also isomerized. The enzyme was strongly activated by 1.0 mM Mg
2+
but only partially activated by 1.0 mM Co
2+
. The respective

K
m

values for Mg
2+
and Co
2+
were 0.3 and 0.003 mM. Mg
2+
and Co
2+
appear to have separate binding sites on the isomerase. These cations also protect the enzyme from thermal denaturation and from D-sorbitol inhibition. The optimum temperature for ketose formation was 70 to 80 C at pH values ranging from 7 to 9. D-Sorbitol acts as a competitive inhibitor with a

K
i

of 5.5 mM against D-glucose, D-xylose, and D-ribose. Induction experiments, Mg
2+
activation, and D-sorbitol D-sorbitol inhibition indicated that a single enzyme (D-xylose isomerase) was responsible for the isomerization of the pentoses, methyl pentose, and glucose.
Death of
Staphylococcus aureus
in Liquid Whole Egg Near pH 8
Authors: Ng Henry , Garibaldi John A.
Published: December 2020

Incubating and shaking
Staphylococcus aureus
in liquid whole egg causes a decline in viability. During the period of agitation, the natural pH of the egg rises from about 7.2 to between 8.0 and 8.2 as a result of a loss of carbon dioxide. However, if the pH of the egg is prevented from rising, either by not shaking or by addition of a buffer,
S. aureus
will grow. The cause of death is traced to the presence of lysozyme of egg white. Interestingly, the action of lysozyme is not attributable to its bacterial lytic property but, instead, to the basicity of the lysozyme molecule. This conclusion is supported by the fact that the lytic property of lysozyme is known to have its optimal activity near neutrality and by the finding that protamine sulfate, a nonenzymatic basic polypeptide, also caused death of
S. aureus
at pH 8.0 but not at 7.0. It was postulated that the rise in pH renders the bacterial cells more negatively charged, so that in the presence of positively charged molecules like lysozyme or protamine sulfate a complex is formed, agglutinating the cells.
Microflora of Maize Prepared as Tortillas
Authors: Capparelli Edward , Mata Leonardo
Published: December 2020

Very little is known of the microflora in tortillas, the major component in the diet of many Guatemalans and other Central Americans. Based in a Guatemalan highland Indian village, this study examined the types and amounts of bacteria, yeasts, and molds in tortillas and in their maize precursors. Coliforms.
Bacillus cereus
, two species of
Staphylococcus
, and many types of yeast were the main contaminants, but low concentrations of alpha-hemolytic
Streptococcus
, facultative
Clostridium
, and other bacterial types were also found. When tortillas were first cooked, the bacterial counts dropped to 1,000 or fewer organisms per g, a safe level for consumption. Under village conditions, bacterial counts regained precooking levels (about 10
8
organisms/g) within 24 h and rose even higher after 48 h. Reheating caused very little change; hence, bacterial levels remained very high in old tortillas kept for later consumption. A search for the sources of contamination showed that most came from water used in preparation and from the soiled hands of women preparing the tortillas. As an attempt to correct certain nutritional needs of the population, the Institute of Nutrition for Central America and Panama initiated a tortilla fortification project in the Guatemalan village. The bacterial counts in fortified tortillas did not differ significantly from those in ordinary tortillas. Furthermore, the level of contamination was constant among tortillas of different sizes and among tortillas made from different types of maize.
Membrane Filter Procedure for Enumerating the Component Genera of the Coliform Group in Seawater
Authors: Dufour A. P. , Cabelli V. J.
Published: December 2020

A facile, quantitative, membrane filter procedure (mC) for defining the distribution of coliform populations in seawater according to the component genera was developed. The procedure, which utilizes a series of in situ substrate tests to obviate the picking of colonies for identification, also provides an estimate of the total coliform density. When pure cultures of
Escherichia coli, Klebsiella pneumoniae
, and
Enterobacter cloacae
were suspended in seawater and held at 4 C for 24 h, between 56 and 100% of the cells which grew on nutrient agar spread plates at 35 C could be recovered by the mC procedure. Confirmation as coliforms of typical colonies from natural samples was about 95%. Assay variability was found to be insignificant. The recovery of coliforms from marine waters by the mC procedure was comparable to those obtainable by current methods.
Klebsiella
was differentiated by the urease reaction and
E. coli
by its ability to form indole. The confirmation frequencies for colonies designated as
Klebsiella
and
E. coli
by the in situ tests approached 95% for the former and 98% for the latter.
Production of Aflatoxin on Soybeans
Authors: Gupta S. K. , Venkitasubramanian T. A.
Published: December 2020

Probable factors influencing resistance to aflatoxin synthesis in soybeans have been investigated by using cultures of
Aspergillus parasiticus
NRRL 3240. Soybeans contain a small amount of zinc (0.01 μg/g) bound to phytic acid. Autoclaving soybeans at 15 pounds (6803.88 g) for 15 min increases the aflatoxin production, probably by making zinc available. Addition of zinc to both autoclaved and nonautoclaved soybeans promotes aflatoxin production. However, addition of varying levels of phytic acid at a constant concentration of zinc depresses aflatoxin synthesis with an increase in the added phytic acid. In a synthetic medium known to give good yields of aflatoxin, the addition of phytic acid (10 mM) decreases aflatoxin synthesis.
Production of Aflatoxin M in a Liquid Medium
Authors: Pai M. Ramachandra , Bai N. Jayanthi , Venkitasubramanian T. A.
Published: December 2020

Aspergillus flavus
NRRL 3251 grown on modified yeast extract-sucrose medium produced 1 mg of aflatoxin M
1
per 100 ml of medium.
Thermal Profile of a
Bacillus
Species (ATCC 27380) Extremely Resistant to Dry Heat
Authors: Bond Walter W. , Favero Martin S.
Published: December 2020

Spores of
Bacillus
sp. ATCC 27380 were exposed at intervals to dry-heat temperatures ranging from 125 to 150 C. D-values from 139 to 2.5 h were obtained.
Effect of pH on Sporulation of
Bacillus Stearothermophilus
Authors: Yazdany S. , Lashkari K. B.
Published: December 2020

An improved broth medium was developed for high growth yields of
Bacillus subtilis
var.
niger
NCIB 8649,
Bacillus cereus
NCIB 9373, and
Bacillus stearothermophilus
NCIB 8919 and ATCC 7953. Sporulation was abundant (1.1 × 10
8
B. subtilis
var.
niger
and 9.2 × 10
7
B. cereus
per ml) at an initial pH of 7.0. Sporulation of both strains of
B. stearothermophilus
took place (1.9 × 10
7
and 2.4 × 10
7
/ml, respectively) in this medium when initial pH values of 7.7 to 8.7 were used.
Changes in Microbial Population During Fermentation of Feedlot Waste with Corn
Authors: Hrubant G. R.
Published: December 2020

A new process for recycling feedlot waste involves the fermentation of liquid from this waste combined with corn. Changes in the flora of this silage-like fermentation were followed. The fermentation was dominated by lactobacilli and yeasts, which initially constitute 1% or less of the natural flora. The species of yeasts and lactics involved were characterized. The fermentation has two phases. A single heterolactic species multiplied rapidly for the first 24 h until it represented 95% of the lactobacilli and more than 90% of the total microflora. It displaced the betabacterium predominant among lactics of the original waste; the acid produced killed coliforms and other organisms in feedlot waste; and the acetic acid produced probably caused the death of the dominant native yeast
Trichosporon cutaneum
(de Beurm., Gougerot et Vaucher) Ota. The peak lactobacillus count remained constant (about 2 × 10
9
organisms/g [wet weight]) throughout the rest of the fermentation. Homolactics dominated the later phase and yeasts increased to 9.5 × 10
7
organisms/g (wet weight). At 6 days, a stable mixture of three lactobacilli was present, one streptobacterium, one thermobacterium, and one betabacterium. Similarly, yeasts stabilized as a mixture of two
Candida
sp. and one
Pichia
sp. The dominant species of lactics were characterized. Information on the sequence of microorganisms provides a basis for enhanced protein synthesis in the fermentation.
An Unstable Strain of
Aspergillus foetidus
Segregating Proline Auxotrophs
Authors: Chang L. T. , Tuveson R. W.
Published: December 2020

Two basic colony types have been obtained through single conidial isolation from the Bode strain of
Aspergillus foetidus
as well as from mutants of this unstable strain. Type I is prototrophic whereas type II is an auxotroph requiring proline. When a type I strain is grown on complex medium it gradually becomes overwhelmed by type II sectors of growth. However, essentially pure cultures of type I can be maintained on minimal medium (lacking proline). The yield of glucoamylase from type II cultures is less than half that obtained with type I cultures. The instability of type I cultures when grown on complex medium can not be explained by heterokaryosis or the presence of virus like particles found in the original Bode strain and its derivatives. The isolation of five stable prototrophic strains obtained as more rapidly growing sectors from type I subcultures grown on complex medium suggests that the instability most probably results from a duplicated chromosomal segment or other chromosomal oberration analogous to those described in
A. nidulans
.
Assay and Relationship of HT-2 Toxin and T-2 Toxin Formation in Liquid Culture
Authors: Kotsonis Frank N. , Ellison Robert A.
Published: December 2020

Both T-2 toxin and HT-2 toxin can be conveniently quantitated in crude extracts by using a combination of thin-layer chromatography and fluorodensitometry. This technique was used to follow the production of these toxins by liquid cultures of
Fusarium poae
(NRRL 3287). T-2 toxin was produced prior to HT-2 toxin and hexadeuterio-T-2 toxin was converted by the culture to trideuterio-HT-2 toxin.
Effect of Aflatoxin on Phagocytosis of
Aspergillus fumigatus
Spores by Rabbit Alveolar Macrophages
Authors: Richard J. L. , Thurston J. R.
Published: December 2020

Rabbits were given daily doses of aflatoxin B
1
equivalents of 0.03, 0.05, 0.07, and 0.09 mg for a 2-week period. Macrophages were harvested at the end of the experimental period, and in vitro phagocytosis experiments were conducted using
Aspergillus fumigatus
spores as ingestion particles. Alveolar macrophages from rabbits given the above doses of aflatoxin had reduced phagocytic activity when compared with macrophages from control rabbits. Incorporation of serum from the aflatoxin-treated rabbits in the in vitro culture system resulted in less stimulation of phagocytosis by macrophages from control rabbits when compared with the same system incorporating control serum. Stimulation of phagocytosis by macrophages was least when both serum and macrophages from aflatoxin-treated rabbits were used in the in vitro system.
Effects of Trace Metals on the Production of Aflatoxins by
Aspergillus parasiticus
Authors: Marsh Paul B. , Simpson Marion E. , Trucksess Mary W.
Published: December 2020

Certain metals added as salts to a defined basal culture medium influenced the level of aflatoxin production by
Aspergillus parasiticus
in the low microgramsper-milliliter range of the added metal. In many cases no change or a relatively small change in mat weight and final pH of the medium accompanied this effect. With zinc at added levels of 0 to 10 μg/ml in the medium, aflatoxin increased 30-to 1,000-fold with increasing of zinc, whereas mat weight increased less than threefold. At 25 μg of added zinc per ml, aflatoxin decreased, but mat weight did not. At an added level of 25 μg or less of the metal per ml, salts of iron, manganese, copper, cadmium, trivalent chromium, silver, and mercury partly or completely inhibited aflatoxin production, without influencing mat weight.
Microbiological Characteristics of Dungeness Crab (
Cancer magister
)
Authors: Lee J. S. , Pfeifer D. K.
Published: December 2020

Aerobic, heterotropic microorganisms of Dungeness crab (
Cancer magister
) were isolated from raw crab, cooked crab, crab meats obtained during commercial processing, and from retail crab meat samples. Each microbial isolate was then identified to the genus level employing the revised replica plating procedure. Microbial groups most commonly isolated from crab meat were, in the order of predominance,
Moraxella, Pseudomonas, Acinetobacter, Arthrobacter, Micrococcus, Flavobacterium-Cytophaga
, and
Bacillus
sp.
Proteus, Staphylococcus
, yeasts,
Vibrio
, and
Lactobacillus
sp. were found less frequently in some samples. Distribution patterns of microbial flora in crab meat revealed the presence of three classes of microorganisms. Microorganisms that originated from the raw crab and gained predominance by growth during refrigerated storage were
Moraxella, Pseudomonas, Acinetobacter
, and
Flavobacterium-Cytophaga
sp. Those that originated from the crab but did not grow in meat were
Arthrobacter
and
Bacillus
sp.
Micrococcus, Staphylococcus
, and
Proteus
sp. were introduced during processing, but they did not grow in the refrigerated crab meat.
Antibacterial Activity of the Lactoperoxidase System in Milk Against Pseudomonads and Other Gram-Negative Bacteria
Authors: Björck L. , Rosén C-G. , Marshall V. , Reiter B.
Published: December 2020

Products of thiocyanate oxidation by lactoperoxidase inhibit gram-positive bacteria that produce peroxide. We found these products to be bactericidal for such gram-negative bacteria as
Pseudomonas
species and
Escherichia coli
, provided peroxide is supplied exogenously by glucose oxidase and glucose. By the use of immobilized glucose oxidase the bactericidal agent was shown to be dialyzable, destroyed by heat and counteracted, or destroyed by reducing agents. Because the system is active against a number of gram-negative bacteria isolated from milk, it may possibly be exploited to increase the keeping quality of raw milk.
Microwave Sanitization of Color Additives Used in Cosmetics: Feasibility Study
Authors: Jasnow S. B. , Smith J. L.
Published: December 2020

Microwave exposure has been explored as a method of microbiologically sanitizing color additives used in cosmetic products. Selected microbiologically unacceptable cosmetic color additives, D&C red no. 7 Ca lake (certified synthetic organic color), carmine (natural organic color not subject to certification), and chromium hydroxide green (inorganic color not subject to certification), were submitted to microwave exposure. Gram-negative bacteria were eliminated, as verified by enrichment procedures, and levels of gram-positive bacteria were reduced. Generally, analytical and dermal safety studies indicated no significant alterations in physical, chemical, and toxicological properties of the colors. Sanitization was also successfully performed on other colors (D&C red no. 9 Ba lake, D&C red no. 12 Ba lake, D&C green no. 5, and FD&C red no. 4); initial physical and chemical tests were satisfactory. Results indicated that this method of sanitization is feasible and warrants further investigation.