bluuebunny/crossref_metadata_2025 huggingface dataset:
Bacterial Degradation of Detergent Compounds
Authors: Goodnow Robert A. , Harrison Arthur P.
Published: December 2020

A survey for surfactant degradation among aerobic bacteria has been undertaken. Tests have been made in peptone medium where such a degradation, if it occurs, will be gratuitous. Tallow-alkyl-sulfate, alkyl-ethoxylate-sulfate, and linear-alkyl-benzene-sulfonate were used. Forty-five strains of 34 species in 19 genera degrade one or more of these detergent compounds. With some species, the surfactant inhibits degradation without inhibiting growth, whereas with one species slight degradation took place even at a toxic concentration of surfactant.
Metabolic Process During the Repair of Freeze-Injury in
Escherichia coli
Authors: Ray B. , Speck M. L.
Published: December 2020

After
Escherichia coli
was injured by freezing, the repair process was studied during incubation of the cells for 2 hr at 25 C in 0.5% K
2
HPO
4
at
p
H 7.0 in the presence of specific metabolic inhibitors. The repair in K
2
HPO
4
was not affected by inhibitors of the synthesis of protein, nucleic acids, and mucopeptide. These inhibitors prevented growth of the repaired cells in a minimal broth at 35 C for 24 hr (except actinomycin D and hydroxyurea). Several uncouplers of adenosine triphosphate (ATP) synthesis reduced the repair process in K
2
HPO
4
, but only cyanide and azide prevented growth in minimal medium. Data indicated that the cells synthesized energy in the form of ATP and probably utilized it for the repair process. Addition of ATP also facilitated the repair of injury. The freeze-injured cells showed extreme susceptibility to surface-active agents and lysozyme. The repaired cells, like the uninjured cells, became relatively resistant to these compounds.
Microfermentation Series for Identification of Single Colonies of
Enterobacteriaceae
Authors: Huhtanen C. N. , Naghski J. , Dellamonica E. S.
Published: December 2020

Microfermentation tests for members of the family
Enterobacteriaceae
were devised by using agar solutions in disposable, multi-welled, plastic trays. The tests could be made directly from isolated colonies picked from agar plates and represented a considerable saving in time, labor, and materials over the conventional methods. Tests were formulated for determining carbohydrate fermentations, citrate utilization, motility, amino acid decarboxylation, and production of H
2
S, indole, urease, and acetyl-methyl-carbinol.
Plate-Slide for the Culture and Morphological Observation of Fungi
Authors: Richter Marian W. , Amsterdam Daniel
Published: December 2020

Adaptation of a polystyrene plate-slide is extremely well suited for the simultaneous macroscopic and microscopic diagnosis of fungi. This technique obviates the disorientation of identifying structures when cultures are mechanically disaggregated during preparation of slides for microscopy.
Comparison of Streptococcal R Antigens
Authors: Wilkinson Hazel W.
Published: December 2020

At least four distinct nonspecific protein R antigens were found in streptococci of groups A, B, and C by immunodiffusion in agar gel with anti-R sera.
Effect of Sodium Polyanetholesulfonate on Antimicrobial Systems in Blood
Authors: Belding M. E. , Klebanoff S. J.
Published: December 2020

Sodium polyanetholesulfonate (SPS), an anticoagulant which inhibits the antimicrobial systems of blood, is used widely in blood culture media. The addition of SPS to experimental blood cultures inoculated with small numbers of a variety of organisms caused a striking increase in recovery of these organisms. Sodium fluoride also increased the incidence of positive blood cultures with some organisms. SPS completely inhibited serum antibacterial activity and serum-dependent phagocytosis (and killing) by isolated leukocytes at a concentration usually employed in blood culture media. SPS also stimulated both glucose C-1 oxidation in resting leukocytes and formate oxidation in both resting and phagocytosing leukocytes in serum-free systems. These in vitro studies support the concept that SPS is a useful additive to blood culture media and further elaborate on the mechanism of its inhibition of the microbicidal activity of blood.
Isolation and Identification of Psychrophilic Species of
Clostridium
from Milk
Authors: Bhadsavle C. H. , Shehata T. E. , Collins E. B.
Published: December 2020

Four of 48 raw milk samples contained catalase-negative, gram-positive, motile, sporeforming, rod-shaped bacteria that grew optimally at 22 to 30 C and slowly at low temperatures. Isolates from two samples had a minimal growth temperature of 4 C, were anaerobic, and had characteristics similar to
Clostridium hastiforme
; those from the other two samples had a minimal growth temperature of 0 � 1 C, were anaerobic, aerotolerant, and had characteristics similar to
C. carnis
. Specific growth rates, doubling times, ability to grow in pasteurized milk stored in commercial cartons, and resistance of spores to heating were determined for one strain of
C. hastiforme
.
Cultural Characteristics of a Cell Line Derived from an Equine Sarcoid
Authors: Watson R. E. , England J. J. , Larson K. A.
Published: December 2020

A cell line, derived from a spontaneous equine connective tissue tumor (equine sarcoid), has been established. The morphological and growth characteristics indicative of malignant transformation of the cells include a disoriented, rapid growth and loss of contact inhibition. Further evidence of transformation is the agglutination of these cells by concanavalin A and their ability to divide in semisolid media.
Measurement of Respiratory Volume for Virus Retention Studies in Mice
Authors: Fairchild Glen A.
Published: December 2020

A pressure plethysmograph for measuring respiratory volume in mice during exposure to virus aerosols is described. The respiratory frequency and tidal volume were measured, and from these data the minute ventilation was calculated. The mean respiratory frequency of adult, male mice was 255 per min; the mean tidal volume of 0.18 ml was inversely related to respiratory frequency. The standardized mean minute ventilation rate was 1.46 ml per g of body weight. The respiratory frequency and tidal volume of CD-1 and HA/ICR strains of mice of the same age were similar. The respiratory retention rate for a 2.7-μm aerosol of vesicular stomatitis virus was 41%, and 58% of the virus retained was found in the trachea and lung.
Adsorption of Colloidal Iron by Bacteria
Authors: Macrae I. C. , Edwards J. F.
Published: December 2020

The adsorption of iron from a positive-iron sol by species of seven bacterial genera was examined by electron microscopy. All species precipitated the iron from the sol, and the bacterial cells became encrusted with iron. This was related to iron deposition in surface water supplies.
Vitamin A Adjuvant with
Arizona hinshawii
Bacterin
Authors: Adler H. E. , DaMassa A. J.
Published: December 2020

Vitamin A provided adjuvant effect for
Arizona hinshawii
bacterin in protection of
Coturnix
quail against severe challenge.
Detection of Hepatitis B Antigen by Counter-Immunoelectrophoresis: Enhancing Role of Homologous Serum Diluents
Authors: Dreesman Gordon R. , Hollinger F. Blaine , Melnick Joseph L.
Published: December 2020

Dilution of hyperimmune hepatitis type B antibody in undiluted homologous species normal serum has resulted in enhanced sensitivity for detecting hepatitis B antigen by a discontinuous counter-immunoelectrophoresis method compared to hepatitis type B antibody diluted in heterologous species normal serum or buffer solutions.
Effects of Irradiation on the Survival of Virus in West Coast Oysters
Authors: Di Girolamo Rudolph , Liston J. , Matches J.
Published: December 2020

Gamma irradiation was evaluated as a means of inactivating poliovirus in shucked and whole shellfish. Results indicated that there was a significant survival of virus at all levels of radiation tested.
Effect of Low-Roughage Diets on the Microflora and Lipid Metabolism in the Rumen
Authors: Latham M. J. , Storry J. E. , Sharpe M. Elisabeth
Published: December 2020

Changing the diet of five lactating cows and one nonlactating cow from high to low roughage induced milk fat depression in the lactating cows and altered the composition of the rumen microflora. While the numbers of lactic and propionic acid-producing bacteria increased, the numbers of
Butyrivibrio
spp. decreased. The numbers of lipolytic bacteria and the in vitro lipolytic activity of the rumen fluid were also decreased, as was the extent of hydrogenation of linoleic and linolenic acids combined in soybean oil incubated in vitro with rumen fluid. It is suggested that among the bacterial population in the rumen the vibrios, which were adversely affected by the low-roughage diets, may contribute significantly to both lipolysis and hydrogenation in the rumen.
Thermal Injury and Recovery of
Bacillus subtilis
Authors: Miller L. Lenkart , Ordal Z. John
Published: December 2020

Exposure of
Bacillus subtilis
NCTC 8236 to sublethal temperatures produced a change in the sensitivity of the organism to salt and polymyxin. After 30 min at 47 C, 90% of the population was unable to grow on a modified sulfite polymyxin sulfadiazine agar containing an added 1% NaCl, 1% glucose, and 1% asparagine. The data presented demonstrate that thermal injury results in degradation of both 16
S
and 23
S
ribonucleic acid (RNA) and in damage to the cell membrane, suggested by leakage into the heating mestruum of material absorbing at 260 nm. When the cells were placed in a recovery medium (Trypticase soy broth), complete recovery, indicated by a returned tolerance to salt and polymyxin, occurred within 2 hr. The presence of a protein inhibitor (chloramphenicol) and cell wall inhibitors (vancomycin and penicillin) during recovery had no effect, whereas the presence of an RNA inhibitor (actinomycin D) effectively inhibited recovery. Further data demonstrated that the injured cells were able to resynthesize both species of ribosomal RNA during recovery by using the fragments which resulted from the injury process. Also, precursor 16
S
and precursor 23
S
particles accumulated during recovery. The maturation of the precursor particles during recovery was not affected by the presence of chloramphenicol in the recovery medium.
Bacteriophage Typing of Clinically Isolated
Serratia marcescens
Authors: Hamilton Rex L. , Brown William J.
Published: December 2020

A bacteriophage-typing scheme for the differentiation and classification of clinically isolated strains of
Serratia marcescens
was developed. Thirty-four
Serratia
bacteriophages were isolated from sewage and used to type 185 of 204 isolates (90.6%) of
S. marcescens
into 23 bacteriophage groups representing 71 types. Different bacteriophage types occurred at different intervals, suggesting that particular strains of
S. marcescens
are found at certain times. A correlation was found between inositol fermentation and bacteriophage type and between susceptibility to carbenicillin and bacteriophage type. However, there was no relationship between source of isolate and bacteriophage type. Bacteriophage typing of
S. marcescens
should provide a system which will aid in determining the origin of nosocomial
Serratia
infections.
Comparative Characteristics of Human and Porcine Staphylococci and Their Differentiation in Burn Xenografting Procedures
Authors: Smith Rodney F. , Bettge Carol L.
Published: December 2020

Staphylococcus epidermidis
from porcine skin differed from human cutaneous
S. epidermidis
in that the former strains were principally of the Baird-Parker biotype III group. The porcine-type strains were more proteolytic on casein and gelatin than were human strains, which were primarily of biotype II. Porcine strains were also elastolytic. Using supernatant fluids of broth cultures, the biotype II strains, but not the type III strains, were lipolytic in action on triolein. Both types of staphylococci were similar in enzymatic activities on Tween 80, egg yolk, and tributyrin. Elastase activity was not found in broth supernatant fluid of these bacteria. The porcine strains were retarded or inhibited from growing in media at
p
H 5.5. Action on casein agar followed by demonstration of elastase activity were used as markers to detect the porcine
S. epidermidis
strains in xenografts and on human burn wound grafting sites.
Microtissue Culture Test for the Titration of Low Concentrations of Diphtheria Antitoxin in Minimal Amounts of Human Sera
Authors: Quevillon Marc , Chagnon André
Published: December 2020

A microtissue culture method for the assay of low concentrations of diphtheria antitoxin in human sera has been developed, using a monkey kidney cell (VERO) culture technique. Results obtained with sera from nonvaccinated children and with immune sera from children vaccinated with three and four injections of diphtheria pertussis tetanus vaccine were in agreement with antitoxin levels considered necessary to denote immunity to diphtheria. The use of microplates and organic buffer for culturing the animal cells improved the stability of the tissue culture system. The described method is sensitive, economical, and applicable for the titration of antitoxin in human sera particularly from infants and children from whom a minimum amount of serum is available.
Value of Desiccated Swabs for Streptococcal Epidemiology in the Field
Authors: Taplin David , Lansdell Lyle
Published: December 2020

Streptococcal surveys in foreign countries or remote areas may be greatly enhanced by the use of calcium alginate swabs desiccated in sterile silica gel. Delays of up to 4 weeks before return to a base laboratory are feasible, and the need for fresh media or laboratory facilities in the field may be eliminated. Comparison of direct plating on crystal violet blood agar versus delayed silica gel preservation during surveys in Uganda, Haiti, Colombia, and Miami, Fla., showed no significant loss of positive cultures from skin lesions and suggests that desiccated swabs increase the recovery of bacitracin-sensitive
Streptococcus pyogenes
(presumptive group A) from throats.
Accumulation of Only Aflatoxin B
2
by a Strain of
Aspergillus flavus
Authors: Schroeder H. W. , Carlton W. W.
Published: December 2020

A strain of
Aspergillus flavus
isolated from ground black pepper produced only aflatoxin B
2
on several natural substrates.
An Improved Method for Enumeration of X-C Cell Assay for Murine Leukemia Virus
Authors: Spahn Gerard J. , Nims Robert M. , Peters Robert L. , Kenyon Kathryn
Published: December 2020

A modification for the enumeration of X-C syncytia is described wherein the projected image of the entire infected culture is observed. This method is rapid, reliable, and reproducible.
Detection of Type E Botulinal Toxin in Cultures by Fluorescent-Antibody Microscopy
Authors: Aalvik B. , Sakaguchi G. , Riemann H.
Published: December 2020

Vegetative cells of toxigenic
Clostridium botulinum
type E cultures were stained with fluorescent antitoxin prepared against purified toxin. The staining seems to be specific.
Recognition of
Citrobacter diversus
in the Clinical Laboratory
Authors: Smith R. F. , Dayton S. L. , Chipps D. D.
Published: December 2020

Characteristics and antibiotic sensitivities of
Citrobacter diversus
are described, and a minimal number of diagnostic tests to identify this organism in a clinical laboratory are suggested.
Byssochlamyopeptidase A, a Rennin-like Enzyme Produced by
Byssochlamys fulva
Authors: Chu Fun Sun , Nei Peter Y. W. , Leung Piera Shu C.
Published: December 2020

The production of a rennin-like enzyme by
Byssochlamys fulva
varied considerably with the isolates tested. Among the seven isolates tested, NRRL 2260, IMI 83277, and N.Y. 1 were good enzyme producers. The enzyme produced by isolate IMI 83277 was purified approximately 20-fold after (NH
4
)
2
SO
4
precipitation, diethylaminoethyl-cellulose chromatography and Sephadex G-100 gel filtration. The partially purified enzyme has a
p
H optimum at 2.9 and a temperature optimum around 60 C. The enzyme appeared to be relatively stable at 40 C between
p
H 3.0 and
p
H 6.85. A name, byssochlamyopeptidase A, was proposed for this new enzyme. The milk-clotting activity of byssochlamyo-peptidase A is dependent on
p
H and appeared to be minimal at
p
H 6.2 or above. No extensive proteolysis has been observed during the milk-clotting process. The non-trichloroacetic acid-precipitable nitrogen titration curve on skim milk was comparable to that catalyzed by animal rennet.
Effect of Variations in Conditions of Incubation upon Inhibition of
Staphylococcus aureus
by
Pediococcus cerevisiae
and
Streptococcus lactis
Authors: Haines William C. , Harmon L. G.
Published: December 2020

The effects of
p
H, temperature, proportion of
Staphylococcus aureus
in the inoculum, various strains of effector organism, and various strains of
S. aureus
were examined for their influence on interactions between staphylococci and effector organisms in associative culture. In general, small changes in
p
H had little effect upon either growth of
S. aureus
or production of enterotoxin in associative culture. Inhibition of growth of
S. aureus
caused by effector organisms was much greater at 25 than at 30 C. Proportion of
S. aureus
in the inoculum greatly affected both growth of the staphylococci and production of enterotoxin. Only slight differences were found between strains of either effector organism or
S. aureus
which affected the interactions in associative culture.
Micromethod for Serogrouping
Escherichia coli
Authors: Brent Patricia , Vosti Kenneth L.
Published: December 2020

A micromethod for serogrouping strains of
Escherichia coli
is described. The method is accurate, rapid, and economical in terms of time and reagents utilized to perform the test.
Casein as a Necessary Factor in the Production of Stimulatory Material for Associative Growth of Lactic Streptococci
Authors: Kothari S. L. , Nambudripad V. K. N.
Published: December 2020

Strains of
Streptococcus cremoris
KH and HC produced material that was stimulatory for
S. cremoris
R
6
in milk and in the dialyzable fraction of milk, but not in the dialysate fraction of milk, lactic acid whey, or lactose broth. The addition of casein to these latter media permitted the production of this stimulatory material to occur. Tryptone, peptone, and yeast extract could not be substituted for casein in producing the stimulatory material or in initiating associative growth in the lactic acid whey. The minimum concentration of casein required appeared to be from 2.0 to 2.5%.
Simple Method for Culturing Anaerobes
Authors: Davis C. E. , Hunter W. J. , Ryan J. L. , Braude A. I.
Published: December 2020

A simple, effective method is needed for growing obligate anaerobes in the clinical laboratory. This report describes a pre-reduced anaerobic bottle that can be taken to the bedside for direct inoculation, provides a flat agar surface for evaluation of number and morphology of colonies, and can be incubated in conventional bacteriological incubators. Each anaerobic culture set consisted of two bottles containing brain heart infusion agar and CO
2
. Gentamicin sulfate (50 μg/ml) was added to one of these to inhibit facultative enteric bacilli. Comparison of the anaerobic bottles with an identical aerobic bottle which was also routinely inoculated permitted early identification of anaerobic colonies. Representative species of most anaerobic genera of proven pathogenicity for man have been isolated from this system during 10 months of routine use.
Fermentative and Serological Studies on
Propionibacterium acnes
Authors: Pulverer G. , Ko H. L.
Published: December 2020

Seventy-two
Propionibacterium acnes
strains, among which were five from the American Type Culture Collection, five from the Center for Disease Control, and four of group II of Voss, were thoroughly examined both biochemically and serologically. On the basis of the fermentation of inositol, maltose, mannitol, and sorbitol, eight biotypes were distinguished. By means of tube agglutination tests with the five absorbed antisera, 95, C51, D34, S140, and Beck, 11 serotypes were defined. The biotypes and serotypes showed no striking relationship to each other. Combined biotyping and serotyping is suggested for subdivision of the
P. acnes
species.
In-Use Evaluation of a Commercially Available Set of Quality Control Cultures
Authors: Douglas George W. , Balows Albert , Rhoden Dwane , Tomfohrde Karla , Smith Peter B.
Published: December 2020

Increasing awareness of the need for a uniform quality control program prompted an evaluation of a commercially available set (Bact-Chek) of eight organisms. A protocol was designed in which this set of control cultures was tested simultaneously in the clinical microbiology laboratory of a 400-bed hospital (the Berkshire Medical Center) and in the reference laboratories of the Bacteriology Section of the Center for Disease Control. The results indicate that the Bact-Chek organisms are essentially as advertised: they constitute a basic set of cultures for a quality control program in clinical microbiology. Ninety per cent of the media and reagents (excluding mycobacterial media and reagents) in the clinical laboratory were checked with this set of eight cultures. Additional cultures not in the set were used to check the remaining 10% of the media and reagents.
Virus Susceptibility of a New Simian Cell Line of Fetal Origin
Authors: Kubicek M. T. , Fine D. L. , Bennett D. G. , Malan L. B. , West D. M. , Holloway A. M.
Published: December 2020

The cultivation and characterization of a cell line derived from the foreskin of a fetal, rhesus monkey (rhfs2) are described. This cell line has proven satisfactory for isolation and assay of a variety of viral agents of human and simian origin. Virus titrations performed on foreskin cells yielded titers comparable to, or higher than, those obtained in rhesus monkey kidney cells (LLC-MK2). Replicate isolation attempts in our laboratory from simian clinical specimens have proven rhfs2 superior to LLC-MK2 for ease of detection and frequency of isolation.
Simplified Gas Chromatographic Procedure for Identification of Bacterial Metabolic Products
Authors: Carlsson Jan
Published: December 2020

A rapid and simple procedure is described for analysis of fermentation products from anaerobic bacteria grown in glucose broth. A 1-ml sample of the culture is drained through cation-exchange resin in a Pasteur pipette. The effluent fluid is directly analyzed isothermally in a gas chromatograph for volatile fatty acids (C
2
to C
6
) as well as for lactic, pyruvic, and succinic acids. This procedure is considered to be suitable for routine use in clinical bacteriology.
Rapid Methods for Extracting Autolysins from
Bacillus subtilis
Authors: Brown W. Claiborne
Published: December 2020

Two procedures are described for the extraction of autolysins from whole cells. One method uses 5 M LiCl at 4 C. The amount of enzyme obtained by this method is six times more than that obtained by autolysis of cell walls and fourteen times more than that obtained by extracting cell walls with LiCl. With the other method, cells are extracted with 2% Triton X-100. This is less efficient than the LiCl method but yields about one-half the amount of enzyme obtained by cell wall autolysis and about the same amount as obtained by extracting cell walls with salt. Both procedures yield autolysin with multiple
p
H optima. Autolysins can be extracted from several bacterial species by either the LiCl or the detergent method. The data suggest that these techniques have sufficient sensitivity to detect small differences in autolytic activity among mutants and various organisms and are also suitable for large-scale isolation of autolysin for purification and characterization studies.
Evaluation of the Redesigned Enterotube—a System for the Identification of
Enterobacteriaceae
Authors: Tomfohrde K. M. , Rhoden D. L. , Smith P. B. , Balows A.
Published: December 2020

The redesigned Enterotube has been evaluated with 414 unknown
Enterobacteriaceae
cultures from the stock culture collection of the Center for Disease Control. When the Enterotube was used as recommended by the manufacturer, an average of 96.4% of these cultures were correctly identified. Only two groups (
Salmonella
and
Edwardsiella
) were identified with less than 90% accuracy (89.2 and 87.5%, respectively). The Enterotube now provides a convenient, rapid, and accurate test system for the identification of typically reacting enteric bacteria.
Cryptococcus neoformans
of Unusual Morphology
Authors: Cruickshank J. G. , Cavill R. , Jelbert M.
Published: December 2020

A case of primary cryptococcosis of the lungs was caused by an isolate of
Cryptococcus neoformans
that assumes a giant form in tissue but which has a normal appearance on artificial culture. Electron microscopy revealed gross enlargement of the capsule and plasma membranes in the tissue form.
Salmonella
Serotypes Encountered at the South Dakota Animal Diagnostic Laboratory
Authors: Pierce R. L. , Gates C. E.
Published: December 2020

This paper summarizes the various
Salmonella
serotypes isolated from feed samples and cases of salmonellosis in domestic animals between 1 January 1970 and 1 June 1972.
Aflatoxin Production in Peanut Varieties by
aspergillus flavus
Link and
Aspergillus parasiticus
Speare
Authors: Nagarajan V. , Bhat Ramesh V.
Published: December 2020

Levels of aflatoxin produced in peanuts differed with the genetic variety of plant and with the species and strain of invading fungus. Possibilities for identifying groundnut varieties partially resistant to aflatoxin production are discussed.
Effects of Aflatoxin on Germination and Growth of Lettuce
Authors: Crisan Eli V.
Published: December 2020

The relative susceptibility of 30 cultivars of lettuce to inhibition by aflatoxin was studied. Seed germination was not inhibited by concentrations as high as 1,000 μg/ml in cultivar Imperial 44 or by 100 μg/ml in the remaining cultivars. Hypocotyl elongation was inhibited by 46 to 68% at a concentration of 100 μg of aflatoxin per ml. Seedlings exposed to aflatoxin did not become chlorotic. The similarity between the morphological reaction of plants to coumarin and aflatoxin suggests a common mode of action, but further studies of the physiological basis for the inhibitory reactions induced by these compounds will be necessary before such conclusions will be valid.
Effect of Nitrite and Nitrate on Toxin Production by
Clostridium botulinum
and on Nitrosamine Formation in Perishable Canned Comminuted Cured Meat
Authors: Christiansen L. N. , Johnston R. W. , Kautter D. A. , Howard J. W. , Aunan W. J.
Published: December 2020

Comminuted ham was formulated with different levels of sodium nitrite and nitrate, inoculated with
Clostridium botulinum
, and pasteurized to an internal temperature of 68.5 C. When added to the meat, nitrite concentrations decreased, and cooking had little effect on them. Nitrite concentrations decreased more rapidly during storage at 27 than at 7 C; however they remained rather constant at formulated levels throughout the experiment at both incubation temperatures. The level of nitrite added to the meat greatly influenced growth and toxin production of
C. botulinum
. The concentration of nitrite necessary to effect complete inhibition was dependent on the inoculum level. With 90
C. botulinum
spores/g of meat, botulinum toxin developed in samples formulated with 150 but not with 200 μg of nitrite per g of meat. At a spore level of 5,000/g, toxin was detected in samples with 400 but not with 500 μg of nitrite per g of the product incubated at 27 C. At lower concentrations of nitrite, growth was retarded at both spore levels. No toxin developed in samples incubated at 7 C. Nitrate showed a statistically significant inhibitory effect at a given nitrite level; however, the effect was insufficient to be of practical value. Analyses for 14 volatile nitrosamines from samples made with varying levels of nitrite and nitrate were negative at a detection level of 0.01 μg of nitrite or nitrate per g of meat.
Fractionation of Dipeptidase Activities of
Streptococcus lactis
and Dipeptidase Specificity of Some Lactic Acid Bacteria
Authors: Sørhaug Terje , Solberg Peter
Published: December 2020

Proteins in sonic extracts of
Streptococcus lactis
were separated by starch-gel electrophoresis at high voltage. Each slab was sliced longitudinally, and half was stained for peptidases in a mixture containing a peptide, L-amino acid oxidase (snake venom), peroxidase, and
o
-dianisdine; the other half was stained in amido black for protein. In addition to sonic treatment, trypsin also released enzyme from acetone-treated cells. Glycyl-L-phenylalanine, L-phenylalanyl-glycine, L-alanyl-L-phenylalanine, and L-phenylalanyl-L-alanine served as substrates in characterizing the enzymes. Five different fractions of various specificities appeared in the gels. Broad-range substrate specificities were found for sonic extracts of
S. lactis, S. cremoris, S. durans
, and
Lactobacillus acidophilus
.
Procedure for Drying Leptospiral Antibody on Sand and Sugar for Serological Studies in Leptospirosis
Authors: Myers Donald M.
Published: December 2020

A simple technique is described for drying sera on washed, dry sand or ordinary sugar cubes for the sero-diagnosis of leptospirosis. The results are shown to be very similar to those obtained with fluid sera or sera dried on filter paper discs. Sera adsorbed on sand or absorbed in sugar eliminated some of the problems associated with sera dried on paper. This method is suitable for use in the field and is expected to be of value in epizootiological studies where contamination and chemical denaturation of fluid serum samples held without refrigeration is a problem.
Morphological, Biochemical, and Growth Characteristics of
Pseudomonas cepacia
from Distilled Water
Authors: Carson L. A. , Favero M. S. , Bond W. W. , Petersen N. J.
Published: December 2020

Studies were conducted on three strains of
Pseudomonas cepacia
isolated and maintained in distilled water and on a laboratory-subcultured strain transferred to distilled water. Optimum growth rates and maximum population yields of the four strains in distilled water were obtained at 37 C, although high population levels (10
6
-10
7
/ml) were reached and maintained over extended incubation periods at temperatures from 18 C to 42 C. Two strains were able to grow in distilled water at temperatures ranging from 12 C to 48 C and to survive 48 h and 21 days at 50 C and 10 C, respectively. Cells from distilled water cultures inoculated into Trypticase soy broth showed an immediate two- to three-log drop at upper and lower temperature limits; survivors were able to initiate logarithmic growth. Results obtained in morphological, biochemical, and antibiotic tests affirmed the strain differences noted in growth studies.
Method for Detecting Mycoplasma and Bacterial L-Form Colonies in Relief with an Ordinary Light Microscope by Means of Oblique Light
Authors: Muelas Jose M. , Ales Jose M.
Published: December 2020

A simple method is described for obtaining images in relief of fresh preparations with an ordinary light microscope by lowering the condenser and displacing the objective at an “off-clicked” position.
Identification of
Staphylococcus aureus
by Simultaneous Use of Tube Coagulase and Thermonuclease Tests
Authors: Barry A. L. , Lachica R. V. F. , Atchison F. W.
Published: December 2020

A simple system is described for efficiently detecting both thermonuclease (heat-stable nuclease) and free coagulase for the routine identification of
Staphylococcus aureus
in the clinical laboratory. Valid discrepancies between these two tests are rare enough to permit the use of one test as a control of the other.
Factors Influencing Detection of Salmonellae in Rendered Animal By-Products
Authors: Tompkin R. B. , Kueper T. V.
Published: December 2020

Detection of salmonellae in animal by-products is influenced by the enrichment and plating media and by quantity of product tested, and is related to the total plate count. A linear relationship exists between detection of salmonellae and total plate counts from 10
4
through 10
7
per gram.
Degradation of Methylmercury by Bacteria Isolated from Environmental Samples
Authors: Spangler William J. , Spigarelli James L. , Rose Joseph M. , Flippin Reid S. , Miller Hope H.
Published: December 2020

A total of 207 bacterial cultures, isolated from environmental samples, was screened for ability to degrade methylmercury. Of these, 30 were found positive for aerobic demethylation. Twenty-two of these were shown to be facultative anaerobes and 21 of these degraded methylmercury anaerobically. All positive species volatilized methylmercury aerobically, and methane was produced as a degradation product. Although methylmercury degradation was complete in most cases, material balances indicated some of the inorganic mercury formed was not volatilized and is presumed bound to the cells. All positive isolates were tolerant to at least 0.5 μg of methylmercury per ml, and the extent of volatilization of mercury increased with concentration to the threshold value. The results indicate that demethylating species are prevalent in the environment and may be important in suppressing the methylmercury content of sediments.
Comparative Resistance of Nonsporogenic Bacteria to Low-Temperature Gamma Irradiation
Authors: Anellis Abe , Berkowitz D. , Kemper D.
Published: December 2020

A total of 36 microorganisms, comprising 19 species of 11 genera, were screened for radiation resistance with
60
Co gamma rays at a radiation temperatore of -80 ± 2 C in phosphate buffer (pH 7.0) under vacuum.
Micrococcus radiodurans
was the most resistant organism. An initial population of 2.8 × 10
5
cells per dose of this species survived 2.4 but not 2.7 Mrad. Of the remaining 18 species with initial populations of about 10
6
cells per dose,
Streptococcus faecium
survived 0.9 to 1.5 Mrad, depending on the strain tested.
S. faecalis
QM survived 0.9 but not 1.2 Mrad.
S. faecalis
1539 and
Alcaligenes faecallis
survived 0.6 but not 0.9 Mrad. Three species of
Salmonella
, one strain each of
Escherichia coli, Streptococcus lactis
, and
Aerobacter aerogenes
survived 0.3 but not 0.6 Mrad. The remaining 22 bacteria did not survive 0.3 Mrad, the lowest dose tested. Detailed survival curve determinations for four strains of
S. faecium
, the most resistant of the test bacteria of public health significance, indicated the following order of resistance at -80 C: α21 > θ12 = F
6
> FEC. Each strain produced two exponential survival curves with different slopes, the breaks occurring at 0.3 to 0.5 Mrad. The D values (doses which reduce the microbial population by 90%) of the more resistant cell fractions were two- to three-fold higher than the more sensitive cell fraction. The resistance of strain α21 was determined at different radiation temperature (+5, -30, -80, -140, -196 C). The D value-radiation temperature relationship followed a quadratic equation. Computations of E
a
and Q
10
values (activation energy and temperature coefficient, respectively) showed a very small thermodynamic effect on radiation death. An Arrhenius evaluation of the temperature effect on cell kill indicated that there was no simple physicochemical mechanism which might explain the change in D value as a function of temperature.
Radioimmunoassay for Type A Toxin of
Clostridium botulinum
Authors: Boroff Daniel A. , Shu-Chen Gregory
Published: December 2020

A preparation of pure type A toxin of
Clostridium botulinum
was labeled with
131
I in the presence of chloramine-T and carrier-free isotope. The radioactive toxin (
131
I Tox) was used in a radioimmunoassay procedure similar to that of Berson and Yalow. Dilutions of antibody to the toxin, capable of binding 50% of the added
131
I Tox, were mixed with a sample of the labeled toxin and various concentrations of unlabeled toxin (‚Cold’ Tox). When concentration of Cold Tox were plotted against the ratio
131
I bound/
131
I not bound, a standard curve was established that could be used to estimate the concentration of Cold Tox in a test mixture. This assay was sensitive to as little as 100 mouse minimum lethal dose and was highly specific for the serological type of the toxin used.
Production of D-Alanine by
Corynebacterium fascians
Authors: Yamada Shigeki , Maeshima Haruko , Wada Mitsuru , Chibata Ichiro
Published: December 2020

A strain identified as
Corynebacterium fascians
was found to accumulate extracellular D-alanine from glycerol. Cultural conditions for the accumulation of D-alanine were investigated and, as a result, a yield of 7 g of D-alanine per liter was obtained after a 96-h incubation in a medium containing 5% glycerol, 4% (NH
4
)
2
HPO
4
, and 0.3% corn steep liquor. Optical purity of D-alanine was dependent upon the concentration of corn steep liquor. At the optimal condition, almost optically pure D-alanine was formed and readily isolated (5 g/liter) from the fermentation broth. The product was not contaminated with any detectable amount of other amino acids, except for glycine which was present at a concentration of less than 1 percent.
Biological and Chemical Detection of Trichothecene Mycotoxins of
Fusarium
Species
Authors: Ueno Y. , Sato N. , Ishii K. , Sakai K. , Tsunoda H. , Enomoto M.
Published: December 2020

The procedure for biological and chemical detection of trichothecene-type mycotoxins and its application to the screening of
Fusarium
for toxic strains were described.
Abolition of Swarming of
Proteus
by
p
-Nitrophenyl Glycerin: General Properties
Authors: Williams Fred D.
Published: December 2020

Para-nitrophenyl glycerin (PNPG) was shown to be an effective agent to abolish the swarming of
Proteus mirabilis
and
Proteus vulgaris
on predried solid culture media. The level required to abolish swarming varied with the strain of
Proteus
, the components of the medium, and also with the conditions of incubation. Generally 0.1 to 0.2 mM PNPG effectively abolished swarming for at least 24 h with aerobic incubation. Levels of PNPG that abolished swarming showed no effect upon the growth of the cells, little or no effect upon the motility characteristics of the organisms, and no effect upon the cellular morphology. PNPG was found to be freely water soluble, stable to autoclaving, and to retain biological activity for at least one month in prepared culture media stored under refrigeration.
Evaluation of Agar-Gel Double Diffusion for the Diagnosis of Adenovirus Infection
Authors: Dupuy Harstry J. , Blouse Louis E. , Marraro Robert V.
Published: December 2020

Agar-gel double diffusion was compared to the Laboratory Branch complement fixation test. The efficacy of the agar-gel double diffusion test for the semiquantitation of group-specific adenovirus antibody and its usefulness as a serodiagnostic aid for the evaluation of adenovirus infection was determined.
Improved Yield of Aflatoxin by Incremental Increases of Temperature
Authors: West Sharon , Wyatt R. D. , Hamilton P. B.
Published: December 2020

Increasing the initial temperature of the rice fermentation of
Aspergillus parasiticus
NRRL 2999 from 15 to 21 C after 24 h of incubation and then to 28 C after 48 h resulted in about a fourfold increase in total aflatoxin over the usual fermentation which is held constant at 28 C for 6 days. The percentage of aflatoxin B
1
, the most toxic component, in the total aflatoxin was also increased.
Mycobacterium microti
(Vole Bacillus): a Method for Viable Counts Within 21 Days of Culture
Authors: Sharp Kay
Published: December 2020

A method is described for counting viable units of
Mycobacterium microti
(vole bacillus) suspensions after 21 days of culture on an oleic-albumin agar medium containing 5% defibrinated horse blood, with a tight seal to maintain humidity. This method is important because vole bacillus is an alternative to BCG in the prevention of tuberculosis.
Some Factors Affecting the Activity of Diethylpyrocarbonate as a Sterilant
Authors: Splittstoesser D. F. , Wilkison Martha
Published: December 2020

Quantitative data indicated logarithmic death in 5° Brix Concord grape juice when concentrations of cells under 10
7
/ml were exposed to diethylpyrocarbonate (DEPC). Species differed considerably in their resistance; e.g., 50 ppm reduced the viable count of
Saccharomyces cerevisiae
over nine log
10
cycles, whereas 200 ppm reduced the count of
Byssochlamys fulva
ascospores by only about 1 log. DEPC lethality was enhanced by higher temperatures; destruction at 40 C was 10- to 100-fold greater than at 20 C. Studies on death rates showed that most yeasts and fungal spores were killed during the first hour of exposure, whereas 24 h or longer was needed for maximal destruction of several lactic acid bacteria. Repair of DEPC-induced damage was believed responsible for the slower death rates of the lactics.
Microbiological Evaluation of Cold-Water Shrimp (
Pandalus borealis
)
Authors: Zapatka Francis A. , Bartolomeo Beverly
Published: December 2020

A bacteriological survey of the Maine shrimp industry was conducted to investigate the conditions associated with the production of frozen, raw, peeled shrimp. In-plant samples and finished product units were collected from seven plants. The most probable number of
Escherichia coli
, coliforms, and coagulase-positive staphylococci, as well as aerobic plate counts (APC), were determined. Freshly harvested shrimp collected from fishing vessels had an APC geometric mean of 510/g, and
E. coli
, coliforms, and coagulase-positive staphylococci were absent. Subsequent storage and insanitary practices during processing increased the APC and introduced coliforms. However, the low air temperatures (18 to 45 F) in the plants and the large volumes of cold water (34 F) used during processing inhibited significant bacterial buildup in the finished product.
Preparation of Solid-Phase Immunosorbents by Coupling Human Serum Proteins to Cyanogen Bromide-Activated Agarose
Authors: Sipe J. D. , Schaefer F. V.
Published: December 2020

The method of preparing solid-phase immunosorbents by covalently attaching proteins from whole human serum to cyanogen bromide-activated agarose has been investigated to determine optimum concentrations of cyanogen bromide and protein, and the optimum pH for the maximum attachment of proteins from serum. Two systems in which the above immunosorbents have proved useful are described: the removal of antibodies to normal serum proteins from anti-hepatitis B serum and the removal of light chain antibodies from anti-human immunoglobulin M serum.
Cultivation of Parasitic Leptospires: Effect of Pyruvate
Authors: Johnson R. C. , Walby J. , Henry R. A. , Auran N. E.
Published: December 2020

Sodium pyruvate (100 μg/ml) is a useful addition to the Tween 80-albumin medium for the cultivation of parasitic serotypes. It is most effective in promoting growth from small inocula and growth of the nutritionally fastidious serotypes.
Some Observations on the Incorporation of Novobiocin into Hektoen Enteric Agar for Improved
Salmonella
Isolation
Authors: Hoben D. A. , Ashton D. H. , Peterson A. C.
Published: December 2020

Novobiocin was incorporated into Hektoen enteric agar as a means of suppressing those
Proteus
and
Citrobacter
organisms that produce colonies which are often mistaken for
Salmonella
.
Analysis of Streptococcal Cell Wall Fractions by Curie-Point Pyrolysis Gas-Liquid Chromatography
Authors: Veld J. H. J. Huis In't , Meuzelaar H. L. C. , Tom A.
Published: December 2020

A streptococcal strain, classified as Z
3
III was differentiated from its mutant strain, Z
3
, lacking the type III polysaccharide antigen, by Curie-point pyrolysis gas-liquid chromatography. Differences observed in pyrograms of whole cells or cell envelopes of both strains could be directly related to the pyrolysis pattern of the purified type III antigen. The same results were obtained when streptococcus F III and its mutant were analyzed. Whereas the pyrolysis patterns of the type III antigen extracted from Z
3
III and F III bacteria were identical, marked differences were found in pyrograms of the serologically identical type III antigen isolated from the culture medium. Type III antigen was also easily differentiated from the purified type I, II and IV antigens. From the above findings it was concluded that pyrolysis gas-liquid chromatography can be used as a tool for the quality control and identification of streptococcal cell wall components.
Dermatophyte Test Medium: Evaluation with Nondermatophytic Pathogens
Authors: Salkin I. F.
Published: December 2020

The growth and color change produced on dermatophyte test medium (DTM) by 25 strains of zoopathogenic fungi associated with human skin lesions were evaluated quantitatively. DTM only partially suppressed the development of nondermatophytes, with total growth in most instances comparable with that observed with dermatophytes. Whereas all dermatophytes induced a rapid color change on DTM, several nondermatophytic pathogens induced an equally intense and almost as rapid conversion. The rapidity of this color change and the colonial morphology of these forms on DTM could cause their misidentification as dermatophytes under clinical conditions.
Physicochemical Properties of the Native, Zinc- and Manganese-Prepared Metalloprotease of
Bacillus polymyxa
Authors: Griffin Patrick J. , Fogarty William M.
Published: December 2020

The neutral protease of
Bacillus polymyxa
had a broad pH optimum (6.0 to 7.2) for activity at 37 C. The enzyme was most stable at pH 5.6 to 5.8. The protease had an optimum temperature of 37 C and was quite thermostable up to 35 C, but at higher temperatures the stability decreased rapidly. The substrate specificity of the protease was similar to that of the neutral proteases of other members of the genus
Bacillus
. The enzyme was shown to be a zinc metalloprotease. However, manganous ions had a greater activating and stabilizing influence on the activity of this enzyme than zinc. Replacement of zinc in the native enzyme by manganese resulted in a 50% increase in activity. In addition, the prepared manganese metalloprotease had higher temperature and more alkaline pH optima than the native enzyme.
Evaluation of New Urinary Tract Infection Screening Devices
Authors: Craig William A. , Kunin Calvin M. , DeGroot Jane
Published: December 2020

Several new methods for detection of bacteriuria were studied to evaluate their usefulness as screening procedures. A new filter paper device incorporating dehydrated media and tetrazolium was found to be reliable when compared with the standard pour plate method in the laboratory and with the dip-slide method in a field test. It failed to detect yeasts and slowly growing streptococci. Antibiotics blocked the test when susceptible organisms were present. An agar-cup method was found to be quite reliable, but could be improved by use of differential media. The Griess test was confirmed in a small trial to be highly specific when used in conjunction with a first morning specimen, but of little value with random specimens. Phenzopyridine was found to give false positive reactions. The subnormal glucose test, although highly sensitive and specific, gave too many false positive tests to be useful other than as a screening method.
Viriditoxin Production by
Aspergillus viridi-nutans
and Related Species
Authors: Lillehoj E. B. , Milburn M. S.
Published: December 2020

Bioproduction of viriditoxin on various substrates by strains of the
Aspergillus fumigatus
group was determined under several incubation conditions.
Aspergillus viridi-nutans
strains NRRL 4365 and 576 produced the largest quantities of toxin,
A. brevipes
gave reduced yields, and there was no detectable synthesis by isolates of four related species. After 30 days in static culture at 20 C on various autoclaved agricultural commodities, optimal yields of 440 and 380 mg of toxin were observed per kilogram of sorghum and rice. Toxin levels were reduced on corn, rye, and wheat (40-200 mg/kg); yields were low on cottonseed, barley, and oats. Incubation at 10 C restricted biosynthesis of viriditoxin, and no toxin accumulated on substrates maintained at 5 C for 120 days. In a liquid, yeast extract-sucrose medium, maximal mycotoxin production developed in shake flasks; after 156 h, 10 mg of toxin accumulated per gram of mycelium. Viriditoxin produced in submerged culture was associated with the mycelium; less than 1% was detected in the filtered broth after 156 h of incubation.