bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Frozen Storage Time on Heat Inactivation of
Clostridium botulinum
Type E Toxin
Authors: Yao Modesto G. , Denny Cleve B. , Bohrer C. Wallace
Published: December 2020

Type E toxin of
Clostridium botulinum
, stored in the frozen state, retained its original toxicity level but lost its heat stability as the storage time increased.
Effect of Acetate upon the Formation of Acetoin in
Klebsiella
and
Enterobacter
and its Possible Practical Application in a Rapid Voges-Proskauer Test
Authors: Bryn Klaus , Ulstrup Jan C. , Størmer Fredrik C.
Published: December 2020

Acetate stimulates the formation of acetoin during 1-h incubation of Voges-Proskauer-positive strains of
Klebsiella
and
Enterobacter
. Of these organisms, 124 of 126 strains were recognized as positive in the presence of acetate, and 106 were recognized as positive in its absence.
Discrepancies in the Enumeration of
Escherichia coli
Authors: Ray B. , Speck M. L.
Published: December 2020

Stationary-phase cells of
Escherichia coli
were enumerated by the pour plate method on Trypticase soy agar containing 0.3% yeast extract (TSYA), violet red-bile agar, and desoxycholate-lactose agar, and by the most-probable-number method in Brilliant Green-bile broth and lauryl sulfate broth. Maximum counts were assumed to be those on TSYA. In general, numbers detected were lower with the selective solid media and higher with the selective liquid media. Inhibitory effects, especially on selective solid media varied with the strains of
E. coli
. The lower detection on selective solid media was partly due to the stress induced in some cells by the temperature of the melted media used in the pour plate method. These cells apparently failed to repair and form colonies in the selective media. Improved detection on the selective solid media was achieved by using 1% nonfat milk solids, 1% peptone, or 1% MgSO
4
.7H
2
O in the dilution blanks. Higher detection on selective agar media was effected by surface plating or by surface-overlay plating of the cells. The surface-overlay method appeared to be superior for the direct enumeration of
E. coli
in foods.
Modifications of the Growth Inhibition Test and its Application to Human T-Mycoplasmas
Authors: Black F. T.
Published: December 2020

Several factors were found to influence the growth inhibition test. Inoculum size and amount of antiserum are well known variables, but the method of applying the antiserum, the incubation temperature, and the pH of the agar medium also play significant roles. The growth inhibition test modified according to these findings was found to be specific and well suited for the classification and identification of human T-mycoplasmas.
Rapid Fermentation Confirmation of
Neisseria gonorrhoeae
Authors: Kellogg Douglas S. , Turner Emily M.
Published: December 2020

A rapid sugar fermentation procedure has been developed for the confirmation of
Neisseria gonorrhoeae
from either primary isolation media or purification media. A lightly buffered salt solution with pH indicator and sugars was heavily inoculated with presumptively positive growth. Proper fermentation patterns are obtained in 1 to 4 h with no interference from inhibited contaminants or variation in results due to differing growth requirements of gonococcal strains.
Pour-Plate Method for the Detection of Coagulase Production by
Staphylococcus aureus
Authors: Parisi Joseph T. , Baldwin Jack N. , Sottile Margaret
Published: December 2020

A pour-plate method is described for the detection of coagulase production by
Staphylococcus aureus
. Either Brain Heart Infusion agar or yeast extract-Trypticase soy agar containing swine plasma was the best medium for the detection of coagulase by this method. The advantages of this method and its potential utilization in the clinical laboratory, in food microbiology, and in specialized studies with
S. aureus
are discussed.
Production and Purification of Acid Protease from the Thermophilic Fungus,
Penicillium duponti
K1014
Authors: Hashimoto Hikotaka , Kaneko Yukio , Iwaasa Takashi , Yokotsuka Tamotsu
Published: December 2020

A thermophilic fungus,
Penicillium duponti
K1014, produced an acid protease in a submerged culture. Maximum enzyme production, in a 30-liter fermentor at a preselected optimum growth temperature of 50 C, occurred after 3 days. The productivity of the enzyme was associated with changes of viscosity and pH of culture broth during the growth. The acid protease was isolated from the culture filtrates and was purified ninefold by alcohol precipitation, column chromatography on
O
-(diethylaminoethyl)cellulose, batchwise treatment with
O
-(carboxymethyl)cellulose, and by gel filtration. The purified enzyme was homogeneous on disk electrophoresis and sedimentation analysis. The sedimentation constant
s
20.w
, calculated at a concentration of 0.64%, was 3.98
S
.
Chlamydospore Production and Germ-Tube Formation by Auxotrophs of
Candida albicans
Authors: Balish Edward
Published: December 2020

A prototrophic strain and 21 auxotrophic strains of
Candida albicans
were assessed for their capacity to produce chlamydospores and germ tubes. All of the mutants were able to produce germ-tubes in human serum but only two mutants produced them in defined medium with L-alpha-amino-n-butyric acid as the sole source of nitrogen. Most auxotrophs were not able to produce chlamydospores on corn meal agar with 1% Tween 80, but they could be induced to do so if the medium was supplemented with their growth requirement(s). Although L-cysteine was able to support the growth of two methionine mutants, it did not support chlamydospore formation when added to corn meal agar with 1% Tween 80. Mutants of
C. albicans
that do not form chlamydospores could be incorrectly identified in laboratories that rely on chlamydospore formation for identification.
Production of δ-Endotoxin by
Bacillus thuringiensis
as a Function of Glucose Concentrations
Authors: Scherrer Peter , Lüthy Peter , Trumpi Brüno
Published: December 2020

The insect pathogen
Bacillus thuringiensis
was cultured at different glucose concentrations. Size, protein content, and insecticidal activity of the parasporal inclusions, which are formed during the sporulation process, were measured. Increased glucose concentrations led to bigger crystalline inclusions with a higher content of protein and insecticidal activity. Maximum yields of protein and endotoxin were obtained in a semisynthetic medium that contained glucose concentrations of 6 to 8 g/liter.
Preparation of Metabolites of Spironolactone by Microbial Oxygenation
Authors: Marsheck William J. , Karim Aziz
Published: December 2020

It has been postulated that 3-(3-oxo-7α-methylthio-4-androsten-17α-yl)propionic acid γ-lactone (I) is a key intermediate in the metabolism of the anti-aldosterone agent, spironolactone (3-[3-oxo-7α-acetylthio-17β-hydroxy-4-androsten-17α-yl] propionic acid γ-lactone). In the present study it was found that microbial oxygenation of I by
Chaetomium cochloides
QM 624 gave three metabolites which retained sulfur in their molecules and were found to be identical to the human metabolites of spironolactone.
Fish Viruses: Buffers and Methods for Plaquing Eight Agents Under Normal Atmosphere
Authors: Wolf Ken , Quimby M. C.
Published: December 2020

A universal procedure was sought for plaque assay of eight fish viruses (bluegill myxovirus, channel catfish virus, eel virus, Egtved virus, infectious hematopoietic necrosis virus, infectious pancreatic necrosis virus, lymphocystis virus, and the agent of spring viremia of carp (
Rhabdovirus carpio
), in dish cultures of various fish cells. Eagle minimal essential medium with sodium bicarbonate-CO
2
buffer (Earle’s salt solution) was compared with minimal essential medium buffered principally with tris (hydroxymethyl)aminomethane or
N
-2-hydroxyethylpiperazine-N′-2′-ethanesulfonic acid at a pH or in the range of 7.6 to 8.0 depending upon temperature. Five fish cell lines collectively capable of replicating all fish viruses thus far isolated were tested and quantitatively found to grow comparably well in the three media. Two-phase (gel-liquid) media incorporating the various buffer systems allowed plaquing at 15 to 33 C either in partial pressures of CO
2
or in normal atmosphere, but greater efficiency and sensitivity were obtained with the organic buffers, and, overall, the best results were obtained with tris(hydroxymethyl)aminomethane. Epizootiological data, specific fish cell line response, and plaque morphology permit presumptive identification of most of the agents. At proper pH, use of organic buffers obviates the need for CO
2
incubators.
Acid Sensitivity of the Influenza Virus Hemagglutinin
Authors: Henderson Marilyn , Wallis Craig , Melnick Joseph L.
Published: December 2020

Influenza virus hemagglutinin was shown to be acid resistant if precipitates which form during acidification are first removed. Adsorption of virus to precipitates formed during acidification may cause a virus to be described incorrectly as acid sensitive.
Heat of Combustion of Cells of
Pseudomonas fluorescens
Authors: Powers John J. , Howell A. Julia , Vacinek Sally J.
Published: December 2020

Based upon 161 determinations, the heat of combustion of cells of
Pseudomonas fluorescens
averaged 5.32 kcal/g on an ash-free dry-weight basis. The standard deviation was 0.39 kcal.
Heating Device for Funnels Used in Sterility Testing
Authors: Bowman Frances W. , Knoll Everett W.
Published: December 2020

A heating device is described for maintaining constant temperature in Pyrex funnels used during the performance of sterility tests.
Quantitative Assay for Genus-Specific Leptospiral Antigen and Antibody
Authors: Baker L. A. , Cox C. D.
Published: December 2020

Hemagglutination and hemagglutination inhibition techniques have been developed as quantitative assays for the genus-specific antigen of
Leptospira
and for its antibody.
Rapid, Direct Tissue Culture Test for Toxigenicity of
Corynebacterium Diphtheriae
Authors: Laird Walter , Groman Neal
Published: December 2020

A method for testing toxigenicity of
Corynebacterium diphtheriae
in tissue culture is described. The technique, called the colony overlay test (COT), involves inoculating material from an isolated colony of
C. diphtheriae
to a small area on the surface of an agar medium which overlays a monolayer of toxin-susceptible HeLa cells. If toxin is produced during incubation at 37 C, it diffuses to the tissue monolayer and destroys the cells below the inoculation site. Twenty-four hours after inoculation, organisms are killed and tissue cells are fixed with formaldehyde. The agar overlay is then removed, and the monolayer is stained with crystal violet. Toxin-affected areas fail to stain or stain poorly. A second plate with antitoxin incorporated in the overlay serves as a control for specificity. Forty-eight strains of
C. diphtheriae
were tested by the COT, guinea pig, and in vitro, gel diffusion tests. The COT is as specific as the other two tests, is easy to read, and can be used to test large numbers of isolates for toxin action more conveniently than by animal inoculation.
Resistance to Arbovirus Challenge in Mice Immediately After Vaccination
Authors: Casals Jordi , Buckley Sonja M. , Barry David W.
Published: December 2020

Mice vaccinated with a single injection of formalin-inactivated suspensions of mouse brain tissue infected with arboviruses were markedly protected against a challenge injection administered hours later. The protection observed during the first 2 days after vaccination seemed to be nonspecific, in that it appeared not only with the homologous system but also between arboviruses of different antigenic groups; this phase may be associated with an interferon-like activity of the serum. Overlapping the nonspecific phase was one of specific protection, which seemed to be well-established in its own right by day 3 or 4 after vaccination. Serum neutralizing antibodies against the homologous viruses were detected as early as 24 h after vaccination and in almost all instances by day 3.
Effect of Dyes on Bacterial Growth
Authors: Fung Daniel Y. C. , Miller Richard D.
Published: December 2020

A rapid screening procedure was used to test the effect of 42 dyes on growth of 30 bacteria on solid media. The results indicated that many readily available dyes might have potential application for selective isolation of specific bacterial groups as well as value in differentiating between closely related bacterial taxa. Separation of
Enterobacter
from
Escherichia, Salmonella
from
Shigella
, and
Staphylococcus
from
Micrococcus
by selected dyes was also evaluated.
Method for Simultaneous Measurement of Radioactive and Inactive CO
2
Evolved from Soil Samples During Incubation with Labeled Substrates
Authors: Domsch K. H. , Anderson J. P. E. , Ahlers R.
Published: December 2020

An apparatus is described which allows the simultaneous, continuous, and highly sensitive analysis of inactive and radioactive CO
2
evolved from
14
C-supplemented soils or other materials. The apparatus consists of a control unit, a commercially available conductometric CO
2
analyzer, and fraction collector. A number of model experiments were conducted to demonstrate the potentials of the apparatus. These included analysis of the time course of priming action, when
14
C-glucose was added to soil, separation of CO
2
respiration peaks caused by simultaneous degradation of radioactive and inactive soil supplements, and study of the effects of a fungicide, Benomyl, on degradation of
14
C-labeled glucose. In the last experiment, partial degradation of the fungicide could also be followed.
Production of Staphylococcal Enterotoxins A, B, and C in Colloidal Dispersions
Authors: Woodburn Margy , Morita Toshiko N. , Venn Sharon Zipperer
Published: December 2020

Larger amounts of enterotoxin were produced when
Staphylococcus aureus
S-6 was grown under still (nonshaken) conditions in a medium that was a paste or gel than were produced in a liquid dispersion with the same colloidal ingredient or in control basal broth (4% NZ Amine-NAK containing 50 μg of thiamine per 100 ml and 1 mg of niacin per 100 ml). Four colloidal ingredients were used which had been previously demonstrated to not support enterotoxin production in buffer. The effect of the type of dispersion occurred earlier than that of the colloidal ingredient, but interactions were found. This effect was not observed when the cells were grown with aeration (shaken). Four other strains of
S. aureus
followed a similar pattern for enterotoxins A, B, and C, although liquid and paste with cornstarch and carrageenan were the only media compared to the control broth. Enterotoxins A and B were produced earlier by
S. aureus
S-6, and much greater quantities of enterotoxins were produced for all strains when incubated shaken.
Device for Automatic Rapid Harvest of Roller Culture Supernatant Fluid
Authors: Smith Ralph E. , Kozoman Frank
Published: December 2020

A machine has been designed to remove and replace supernatant fluids automatically from roller culture bottles at frequent intervals.
Recovery of Bacteriophage from Contaminated Chilled and Frozen Samples of Edible West Coast Crabs
Authors: DiGirolamo Rudolph , Daley Michael
Published: December 2020

Edible West Coast crabs (
Cancer magister
and
C. antennarius
) were contaminated with bacteriophage and then held in a chilled or frozen state. Results indicated a significant survival of virus regardless of storage conditions.
Evidence for Four Deoxynucleoside Kinase Activities in Extracts of
Lactobacillus leichmannii
Authors: Powell J. W. , Wachsman J. T.
Published: December 2020

Extracts of
Lactobacillus leichmannii
(ATCC 7830) catalyze the phosphorylation of the four principal deoxynucleosides. Thymidine, deoxyguanosine, and deoxycytidine kinase activities were found to be optimal with deoxyadenosine triphosphate as the phosphoryl donor, whereas deoxycytidine triphosphate was the optimal donor for deoxyadenosine kinase activity.
L. leichmannii
catalyzes the conversion of deoxycytidine to deoxyuridylic acid, probably by a pathway involving deoxycytidylate deaminase.
Clinical Laboratory Experience with the Improved Enterotube
Authors: Painter Barbara G. , Isenberg Henry D.
Published: December 2020

The reactions elicited in this evaluation of the improved Enterotube indicate the efficacy of using this device for the differentiation of the members of the family
Enterobacteriaceae
.
Gentamicin Blood Agar Used as a General-Purpose Selective Medium
Authors: Black William A. , Van Buskirk Frances
Published: December 2020

The potential value of a blood agar medium containing a final concentration of 5.5 μg of gentamicin per ml was assessed in a diagnostic laboratory over an 8-week period. The medium gave increased isolation rates of beta-hemolytic streptococci, other streptococci,
Bacteroides
, clostridia, and yeasts. It also proved valuable in detecting gentamicin-resistant gram-negative bacilli when these were present in heavy mixed culture.
Effects of Natural Microbial Preparations on the Electrokinetic Potential of Bacterial Cells and Clay Minerals
Authors: Kiremidjian Lidia , Stotzky G.
Published: December 2020

A complex mixture of fermentation residues and eutrophication products used commercially as a soil amendment and in various phases of sewage treatment was effective in reducing the electrophoretic mobility of clay minerals (kaolinite and montmorillonite) and cells of
Agrobacterium radiobacter
. The active fraction(s), which is active at very low concentrations, appears to be a stable (to heat, dialysis, concentration, and storage), net negatively charged polymer which may have several positively charged sites. The material does not significantly alter the viscosity or surface tension of aqueous systems and is probably a microbial metabolite(s).
Improved Microtechnique for the Leptospiral Microscopic Agglutination Test
Authors: Cole John R. , Sulzer Catherine R. , Pursell Alfred R.
Published: December 2020

A method for improving the original Galton microtechnique for detecting leptospiral antibodies has been developed. Simultaneous titrations were performed on 281 animal and human sera and 17 hyperimmune sera with the microscopic agglutination (MA) test and the improved microtechnique. Reproducibility of the improved microtechnique was determined independently on 65 animal sera by two laboratory sections. The results obtained by comparing positive test data from human and animal sera indicated that agreement between the original MA test and this new method exceeded 94%, whereas the original Galton microtechnique and the original MA test agreed in a maximum of 77% of the tests. This study indicates that the results obtained with the improved microtechnique are much more comparable to results obtained with the original MA test than are those obtained with the original Galton microtechnique.
Disk Test for the Differentiation of Pneumococci from Other Alpha-Hemolytic Streptococci
Authors: Lorian Victor , Markovits George
Published: December 2020

One hundred twenty-five strains of
Diplococcus pneumoniae
and one hundred twenty-five strains of other alpha-hemolytic streptococci were planted on horse red cell-Brucella agar, and a disk of methicillin was placed on each inoculated plate. All strains were incubated anaerobically at 37 C for 24 h and then exposed to air at 6 C for 48 h. All strains of pneumococci produced a ring of beta-hemolysis surrounding the zone of inhibition produced with the methicillin disk, whereas no strain of alpha-hemolytic streptococci produced beta-hemolysis. It is suggested that this new criterion is useful for the differentiation of pneumococci from other alpha-hemolytic streptococci in those cases where other characteristics were insufficient for an unequivocal identification.
Volatile Compounds Produced in Sterile Fish Muscle (
Sebastes melanops
) by
Pseudomonas putrefaciens, Pseudomonas fluorescens
, and an
Achromobacter
Species
Authors: Miller A. , Scanlan R. A. , Lee J. S. , Libbey L. M.
Published: December 2020

Volatile compounds produced by
Pseudomonas putrefaciens, P. fluorescens
, and an
Achromobacter
species in sterile fish muscle (
Sebastes melanops
) were identified by combined gas-liquid chromatography and mass spectrometry. Compounds produced by
P. putrefaciens
included methyl mercaptan, dimethyl disulfide, dimethyl trisulfide, 3-methyl-1-butanol, and trimethylamine. With the exception of dimethyl trisulfide, the same compounds were produced by an
Achromobacter
species. Methyl mercaptan and dimethyl disulfide were the major sulfur-containing compounds produced by
P. fluorescens
.
Effect of Sodium Nitrite and Sodium Nitrate on Botulinal Toxin Production and Nitrosamine Formation in Wieners
Authors: Hustad Gerald O. , Cerveny John G. , Trenk Hugh , Deibel Robert H. , Kautter Donald A. , Fazio Thomas , Johnston Ralph W. , Kolari Olaf E.
Published: December 2020

Wieners were formulated and processed approximating commercial conditions as closely as possible. Twenty-four batches of product were made with the addition of six levels of sodium nitrite (0, 50, 100, 150, 200, and 300 μg/g), four levels of sodium nitrate (0, 50, 150, and 450 μg/g), and two levels of
Clostridium botulinum
(0 and 620 spores/g). After formulation, processing, and vacuum packaging, portions of each batch were incubated at 27 C or held for 21 days at 7 C followed by incubation at 27 C for 56 days. The latter storage condition approximated distribution of product through commercial channels and potential temperature abuse at the consumer level. Samples were analyzed for botulinal toxin, nitrite, and nitrate levels after 3, 7, 14, 21, 28, and 56 days of incubation. When nitrite was not added, toxic samples were detected after 14 days of incubation at 27 C. At the lowest level of nitrite added (50 μg/g), no toxic samples were observed until 56 days of incubation. Higher levels of nitrite completely inhibited toxin production throughout the incubation period. Nine uninoculated samples, representing various levels and combinations of nitrite and nitrate, were evaluated organoleptically. The flavor quality of wieners made with nitrite was judged significantly higher (
P
= 0.05) than of wieners made without nitrite. The nine samples were negative for 14 volatile nitrosamines at a sensitivity level of 10 ng/g. The results indicated that nitrite effectively inhibited botulinal toxin formation at commercially employed levels in wieners and that detectable quantities of nitrosamines were not produced during preparation and processing of the product for consumption.
Comparative Evaluation of Five Serological Methods for the Diagnosis of Sporotrichosis
Authors: Blumer Sharon O. , Kaufman Leo , Kaplan William , McLaughlin David W. , Kraft Dorothy E.
Published: December 2020

The diagnosis of sporotrichosis can be time consuming. Serological procedures could facilitate the rapid and accurate diagnosis of this disease. A slide latex agglutination (SLA) test for sporotrichosis was developed and compared with the tube agglutination (TA), complement fixation (CF), and immunodiffusion (ID) tests in the serological study of 80 proven human cases of sporotrichosis representing the cutaneous, subcutaneous, and extracutaneous forms of the disease. In addition, the indirect fluorescent antibody (IFA) technique was applied to 61 case sera. In the SLA test, latex particles sensitized with culture filtrate antigens from the yeast form of
Sporothrix schenckii
(B 959) detected 94% of the cases, as compared to 96% of the cases detected by the TA test, 68% by the CF test, and 56% by the ID test. The IFA test detected 90% of the 61 cases. The SLA and ID tests were specific, showing no reactions with sera from 86 persons with no disease or with diseases other than sporotrichosis. Because of its sensitivity, specificity, ease of performance, and ability to provide results in 5 min, the SLA test is highly recommended for routine use in the clinical laboratory.
Comparison of Several Laboratory Media for Presumptive Identification of Enterococci and Group D Streptococci
Authors: Facklam R. R.
Published: December 2020

Bile-esculin (Difco), modified bile-esculin (Difco), selective enterococcus (Pfizer Co.), and eosin-methylene blue agar media were evaluated for accuracy in identifying group D streptococci. The regular and modified bile-esculin media performed equally well, but the selective enterococcus and eosin-methylene blue agars did not accurately differentiate the group D from non-group D streptococci. A modified 6.5% NaCl broth was compared with unmodified 6.5% NaCl broth and
Streptococcus faecalis
(SF; Difco) broth for accuracy in differentiating enterococci from non-enterococci. The modified and unmodified broths worked equally well in the salt tolerance test, but the lot-to-lot variability of SF broth made this medium unusable as an indicator for enterococci. With all seven media, the number of strains giving positive tests decreased when the tests were incubated at 45 C as compared with 35 C, and the number of strains giving negative tests increased. Thus, the number of false-positive identifications decreased, but the number of false-negative identifications increased. Variability in the susceptibility of group D non-enterococcal streptococci to oxacillin and methicillin sensitivity disks limited the usefulness of these tests for presumptive identification of either enterococci or group D streptococci.
Airborne Stability of Simian Virus 40
Authors: Akers T. G. , Prato C. M. , Dubovi E. J.
Published: December 2020

The influence of relative humidity on the airborne survival of simian virus 40 (SV40) was studied by allowing virus aerosols to age in rotating drums at 21 or 32 C and at a relative humidity (RH) value ranging from 22 to 88%. Airborne SV40 virus was stable at every RH tested at 21 C, but aerosols maintained at 32 C were inactivated within 60 min at mid-range RH values. The unusual stability at 21 C over a broad RH range indicates that potentially biohazardous situations may occur under laboratory conditions if this virus becomes accidentally airborne.
Production of Penicillic Acid and Ochratoxin A on Poultry Feed by
Aspergillus ochraceus
: Temperature and Moisture Requirements
Authors: Bacon C. W. , Sweeney J. G. , Robbins J. D. , Burdick D.
Published: December 2020

A strain of
Aspergillus ochraceus
Wilhelm, isolated from poultry feed, produced both penicillic acid and ochratoxin A. Studies demonstrating the ability of this fungus to colonize poultry feed and produce these two mycotoxins under various temperatures and moistures indicated that the interaction was complex. The optimal temperature for conidial development did not vary with moisture, but accumulation of both toxins did. A combination of low temperature, 15 or 22 C, and low moisture favored the production of penicillic acid, whereas high temperature, 30 C, and high moisture favored the production of ochratoxin A.
Induction of Red Color Formation in Cabbage Juice by
Lactobacillus brevis
and Its Relationship to Pink Sauerkraut
Authors: Stamer J. R. , Hrazdina G. , Stoyla B. O.
Published: December 2020

Membrane-filtered cabbage juice, when fermented by
Lactobacillus brevis
under conditions of controlled pH, frequently produced a water-soluble red pigment. The pigment, presumably responsible for imparting a highly objectionable discoloration to sauerkraut, was formed during the post logarithmic phase of growth. Color development is pH dependent (5.2 to 6.3) and can be suppressed by chemical reductants or anaerobic conditions of growth. The compound responsible for discoloration was purified and partially characterized.
Degradation of Methoxylated Benzoic Acids by a
Nocardia
from a Lignin-Rich Environment: Significance to Lignin Degradation and Effect of Chloro Substituents
Authors: Crawford R. L. , McCoy Elizabeth , Harkin J. M. , Kirk T. K. , Obst J. R.
Published: December 2020

Strain A81 of
Nocardia corallina
hydroxylates or demethylates
p
-anisic acid to
p
-hydroxybenzoic acid and isovanillic acid. It demethylates veratric acid to a mixture of vanillic and isovanillic acids. These are both demethylated to protocatechuic acid, which undergoes ring cleavage to afford β-carboxy-
cis-cis
-muconic acid. The intermediacy of protocatechuic acid in the catabolic pathway of veratric acid was confirmed by blocking ring cleavage with an additional substituent in the ring: 5-chlorovanillic acid was demethylated to 5-chloro-protocatechuic acid, which accumulated. Chloro substituents in the ring of other methoxylated benzoic acids also arrested their normal metabolism by the
Nocardia
: an
ortho
-chloro substituent thwarted both demethylation and ring-opening.
ortho
-Hydroxylation of
p
-methoxybenzoic acid to isovanillic acid was unaffected by a chlorine
ortho
to the methoxyl group. Washed whole cells of veratric acid-grown
N. corallina
A81 produced no detected structural changes in an isolated lignin. The implications of this observation are discussed.
Escherichia coli
Field Contamination of Pecan Nuts
Authors: Marcus Karen A. , Amling H. J.
Published: December 2020

More pecan samples collected from grazed orchards were contaminated with
Escherichia coli
than were samples from nongrazed orchards. No differences in frequency of contamination between mechanically and manually harvested nuts occurred. Nutmeats from whole uncracked pecans that were soaked for 24 h in a lactose broth solution containing
E. coli
did not become contaminated. Twentyfour percent of the whole pecans soaked in water for 48 h to simulate standing in a rain puddle developed openings along shell suture lines which did not completely close when the nuts were redried.
Sand Beach Bacteria: Enumeration and Characterization
Authors: Khiyama H. M. , Makemson J. C.
Published: December 2020

Bacteria in the water-saturated sand of a relatively unpolluted sand beach were enumerated by direct microscope and viable counting. The number of interstitial bacteria was estimated to be a significant fraction of the total number of bacteria present. Three hundred sixty-two strains were isolated and submitted to cultural and biochemical tests. Fermentational abilities and the production of indole suggested that a significant number of these bacteria were symbiotically associated with resident metazoans.
Production of a New Type of Acid Carboxypeptidase of Molds of the
Aspergillus niger
Group
Authors: Ichishima Eiji , Yamane Akiko , Nitta Tsuneo , Kinoshita Minoru , Nikkuni Sayuki , Oka Tomoko , Yokoyama Sadaji
Published: December 2020

The ability of 88 fungi, which had been obtained as high-potency strains for acid proteinase production, to produce a new type of acid carboxypeptidase (having on optimal pH of about 3 for hydrolysis of benzyloxycarbonyl-glutamyltyrosine) in surface koji culture was determined. Among the aspergilli, substantial amounts of this new acid carboxypeptidase were produced by
Aspergillus saitoi, A. usamii, A. awamori, A. inuii
, and
A. niger
. Maximum yields of acid carboxypeptidase per gram of substrate were obtained by submerged culture in a medium containing 0.9% defatted soybean and 0.6% wheat bran. However, the maximum enzyme concentration per milliliter was obtained with a medium containing 3% defatted soybean and 2% wheat bran. The terminal pH could be controlled by varying the concentrations of soybean oil meal and wheat bran. The maximum enzyme production was reached after 4 days or more at 30 C.
In Vitro Studies with Modoc Virus in Vero Cells: Plaque Assay and Kinetics of Growth, Neutralization, and Thermal Inactivation
Authors: Davis James W. , Hardy James L.
Published: December 2020

A sensitive and quantitative assay system is described for plaquing Modoc virus in Vero cells. Neutralizing antibodies to Modoc virus could be detected by using this in vitro system by their interference with viral plaque formation. Virus was readily neutralized within 30 min at 37 C by a 1:10 dilution of hyperimmune hamster serum. The rate of neutralization and the total amount of virus neutralized was not altered significantly by the addition of 20 U of guinea pig complement to the hyperimmune hamster serum. A study of the growth of Modoc virus in Vero cells is also presented. After an initial latent period of 20 h, viral titer increased exponentially for 20 h. By 83 h after infection, 8,000 plaque-forming units of virus were detected per cell. The stability of viral infectivity in phosphate-buffered saline at pH 7.4 was evaluated. No reduction in viral titer was detected after 3 days at 7 or 22 C. A continuous decrease in infectivity at 37 C was observed, however, throughout the observation period.
Sensitivity of Three Selected Bacterial Species to Ozone
Authors: Broadwater W. T. , Hoehn R. C. , King P. H.
Published: December 2020

The minimal lethal concentration of ozone in water was determined for three bacterial species:
Escherichia coli, Bacillus cereus
, and
Bacillus megaterium
. A contact period of 5 min was selected. The lethal threshold concentration for the cells of
B. cereus
was 0.12 mg/liter while that for
E. coli
and
B. megaterium
was 0.19 mg/liter. Low concentrations of ozone were ineffective when organic matter was present to interfere with the action of ozone on the bacterial cells. Also determined during the study was the sensitivity of spores of
B. cereus
and
B. megaterium
to ozone in water. The threshold concentration required to kill the spores of both species was 2.29 mg/liter. The cells and spores of these organisms exhibited the “all-or-none” die-away phenomenon normally associated with ozone treatment.
Isolation of Porcine Parvovirus from Commercial Trypsin
Authors: Croghan D. L. , Matchett A. , Koski T. A.
Published: December 2020

The isolation of porcine parvovirus from a lot of commercial 1:250 trypsin is reported and the method is described.
Medium for the Selective Enumeration of Lactic Acid Bacteria from Foods
Authors: Davidson Charles M. , Cronin Faye
Published: December 2020

A nitrite actidione polymyxin agar was developed for the enumeration of lactic acid bacteria. It was effective in recovering organisms from pure cultures and from foods.
Effect of Temperature of the Sensitization Process on the Passive Hemagglutination Test for Hepatitis B Antibody
Authors: Hawkes Royle A.
Published: December 2020

The temperature at which the coupling of antigen to erythrocytes takes place is an important factor in the passive hemagglutination test for hepatitis B antibody. Erythrocytes sensitized at 16 C are much less sensitive for the detection of antibody than are those sensitized at 22 to 41 C.
Effect of Glutaraldehyde on Cell Viability, Triphenyltetrazolium Reduction, Oxygen Uptake, and β-Galactosidase Activity in
Escherichia coli
Authors: Munton T. J. , Russell A. D.
Published: December 2020

Acid (pH 5) and alkaline (pH 8.5) glutaraldehyde solutions were compared for their effects on cell viability, oxygen uptake, and β-galactosidase activities in
Escherichia coli
. The action of glutaraldehyde at pH 7 on dehydrogenase activity was also studied. Dehydrogenase activity was inhibited at aldehyde concentrations which had little effect on cell viability. In contrast, oxygen uptake and β-galactosidase activity took place in cells killed by acid or alkaline glutaraldehyde. The effect of glutaraldehyde on dehydrogenase activity and β-galactosidase activity of disrupted suspensions was also investigated. The dialdehyde was considerably less inhibitory to these enzyme systems than to those of whole cells, and it is thus feasible that the results with whole cells are a consequence of its interaction with, and strengthening of, the outer cell surface, thereby preventing ready access of substrate to enzyme.
Use of Gas Chromatography for Detecting Ornithine and Lysine Decarboxylase Activity in Bacteria
Authors: Lambert Mary Ann S. , Moss C. Wayne
Published: December 2020

A gas-liquid chromatography (GLC) procedure for the detection of L-ornithine and L-lysine decarboxylase (EC 4.1.1.17 and EC 4.1.1.18, respectively) activities of bacteria was developed and evaluated against Møller's method, a conventional biochemical test. Cultures were incubated for 2 to 4 h in a simple growth medium and tested by GLC for putrescine and cadaverine, the direct decarboxylation products of ornithine and lysine, respectively. Results obtained with various
Enterobacteriaceae
, pseudomonads, and vibrios showed that the GLC procedure was superior to the conventional test; clear, well-defined results were obtained within 3 to 5 h, even with cultures which gave weak, delayed, or variable reactions by Møller's method. This GLC procedure for the determination of decarboxylase reactions would be useful in microbiological laboratories for culture identification and for various other enzymatic studies.
Rapid Detection of Contaminated Intravenous Fluids Using the
Limulus
In Vitro Endotoxin Assay
Authors: Jorgensen James H. , Smith Rodney F.
Published: December 2020

Intravenous fluids and administration sets may become contaminated with gram-negative bacteria during use and result in a life-threatening situation to the patient. The
Limulus
in vitro assay for endotoxin was used in two patients whose parenteral fluids had become contaminated with
Pseudomonas aeruginosa
. This test allowed rapid detection of the contaminated intravenous fluids and demonstrated a concomitant endotoxemia in both patients. The same strains of pseudomon were subsequently cultured from each patient's blood, intravenous catheter tip, and parenteral fluid and administration set. A different serotype of pseudomonas was unique to each patient, indicating two separate and unrelated cases of accidental contamination of the administration sets. Endotoxin-like activity was also demonstrated from several brands of commercial human serum albumin, which may contribute low-level activity detectable by the
Limulus
assay.
Deoxyribonucleic Acid Hybridization Studies on
Flavobacterium meningosepticum
Authors: Sottile M. I. , Baldwin J. N. , Weaver R. E.
Published: December 2020

Seventeen flavobacteria, including 12 strains of
Flavobacterium meningosepticum
, were investigated to determine their genetic relationships by deoxyribonucleic acid (DNA)-DNA hybridization and guanine plus cytosine content. The percentage of binding among the strains tested ranged from 6 to 87%. There was no correlation between the serotype and DNA-duplex formation. The guanine plux cytosine content of the representative strains of the five serotypes ranged from 31 to 50%.
T-2 Toxin as an Emetic Factor in Moldy Corn
Authors: Ellison Robert A. , Kotsonis Frank N.
Published: December 2020

Extracts of
Fusarium poae
(NRRL 3287) grown either on sterile corn at 8 C or in Richards solution at room temperature were shown to have emetic activity in pigeons at nonlethal concentration under conditions of oral and intravenous administration. The causative agent was found to be T-2 toxin (3-hydroxy-4,15-diacetoxy-8-[3-methylbutyryloxy]-12,13-epoxy-Δ
9
-trichothecene). Oral and intravenous mean toxic dose values for this compound were found to be 0.72 and 0.15 mg/kg, respectively, as compared with an oral mean lethal dose of 2.75 mg/kg. The fact that T-2 toxin causes emesis at nonlethal concentrations may explain, at least in part, the observance of vomiting as a symptom resulting from ingestion of cereal grains infected with toxic
Fusarium
species containing T-2 or a similar toxin.
Rapid Test for Lysine Decarboxylase Activity in
Enterobacteriaceae
Authors: Brooker Doris C. , Lund Marlys E. , Blazevic Donna J.
Published: December 2020

A 4-h lysine decarboxylase test was performed on 241 clinical isolates of
Enterobacteriaceae
. There was 100% agreement between the rapid-test and reference methods.
Labeling of Antibodies with
3
H-Acetate
Authors: Kalmakoff J. , Parkinson A. J.
Published: December 2020

Antibodies can be labeled with
3
H-iodoacetate at pH 9.8 without significant loss of biological activity, and the labeled antibody can be used to detect viral antigens.
Capillary Tube Catalase Test
Authors: Fung Daniel Y. C. , Petrishko Dianne T.
Published: December 2020

A capillary tube procedure for detection of catalase activities of isolated colonies of pure and mixed cultures on nutrient and blood agar plates is proposed.
Evaluation of a Hemagglutination Test for Human Leptospirosis
Authors: Sulzer Catherine R. , Jones Wallis L.
Published: December 2020

An indirect hemagglutination test for the diagnosis of leptospirosis is described; the test uses a soluble antigen from serotype patoc to sensitize sheep erythrocytes which are then fixed with glutaraldehyde. Evaluation of this procedure indicates that it is more reliable than the conventional macroscopic agglutination test and, in contrast with both microscopic and macroscopic agglutination tests, is positive only with sera from persons with current leptospiral illness. The test is simple and convenient and sensitized fixed cells may be stored for at least a year. In comparison with the macroscopic and microscopic tests, only a single antigen is required.
Lactose-Fermenting
Salmonella
from Dried Milk and Milk-Drying Plants
Authors: Blackburn Billie O. , Ellis E. M.
Published: December 2020

A study of 552 salmonella cultures revealed that 86 (15.6%) of the cultures fermented lactose. These had been isolated from dried milk products and milk-drying plants. Acid and gas were produced in lactose broth. Solid media containing lactose as the key ingredient for the differential reaction were not satisfactory for recognizing salmonella colonies. No problem was encountered in selecting salmonella colonies when bismuth sulfite agar was used.
Aliphatic Hydrocarbons of
Cladosporium resinae
Cultured on Glucose, Glutamic Acid, and Hydrocarbons
Authors: Walker J. D. , Cooney J. J.
Published: December 2020

The carbon source markedly influenced the qualitative and quantitative composition of cellular hydrocarbons in
Cladosporium resinae
. Total lipid and hydrocarbon content was greater in cells grown on
n
-alkanes than in cells grown on glucose or glutamic acid. Glucose-grown cells contained a spectrum of aliphatic hydrocarbons from C
7
to C
36
; pristane and
n
-hexadecane comprised 98% of the total. Cells grown on glutamic acid contained C
7
to C
23
hydrocarbons;
n
-tridecane,
n
-tetradecane,
n
-hexadecane, and pristane made up 74% of the total.
n
-Decane-grown cells yielded C
8
to C
32
compounds, and
n
-hexadecane (96%) was the major hydrocarbon. Cells grown on individual
n
-alkanes from C
11
to C
15
all contained C
11
to C
28
hydrocarbons, and cells grown on
n
-hexadecane contained C
11
to C
32
hydrocarbons. In
n
-undecane-grown cells,
n
-hexadecane and pristane made up 92% of the total, but in cells grown on C
12
to C
16
n
-alkanes the major cellular hydrocarbon was the one on which the cells were grown. This suggests that cells cultured on
n
-alkanes of C
12
or longer accumulate
n
-alkanes prior to oxidizing them.
Identification of the Toxic Principle in a Sample of Poaefusarin
Authors: Mirocha C. J. , Pathre S.
Published: December 2020

A sample of poaefusarin (a mycotoxin suspected of being one of the toxins involved in alimentary toxic aleukia in the U.S.S.R.) was received from a Soviet scientist for evaluation and comparison with other mycotoxins. Although poaefusarin is presumed to be a steroid, analyses by thin-layer chromatography, gas-liquid chromatography, and infrared, ultraviolet, and mass spectrometry could not confirm the presence of a steroid structure. However, 2.5% of the sample was made up of the trichothecene T-2 toxin, an amount sufficient to explain the toxicity found in the rat and rabbit skin toxicity tests. In addition, neosolaniol (0.14%), T-2 tetraol (0.6%), and zearalenone (F-2) (0.43%) were present in the sample. Since the toxicity was found to be associated only with T-2 toxin, no attempt was made to determine the nature of the other nontoxic components of the sample.
Lipolytic Bacteria in the Ottawa River
Authors: Blaise Christian R. , Armstrong John B.
Published: December 2020

Lipolytic bacteria were isolated from two stations on Brewery Creek, an arm of the Ottawa River, during the winter of 1971-72. Total counts were approximately sevenfold higher at the more polluted downstream station, whereas lipolytic counts were about 100-fold higher. At this station, significantly more lipolytic bacteria grew on plates incubated at 20 C than at 4 C, suggesting that the population was comprised of both mesophiles and psychrophiles. However, at the upstream station, approximately the same number were obtained at both temperatures. A total of 434 isolates, mainly from the downstream station, were tentatively classified. The major groups were
Pseudomonas, Acinetobacter-Moraxella
, and
Aeromonas
. Though the total number of lipolytic bacteria was fairly constant throughout the winter, the relative abundance of the acinetobacters dropped from approximately 90% in November to less than 10% in March, and then increased. The aeromonads and pseudomonads showed the opposite trend. Most of the bacteria, though isolated at 4 C, also grew at 30 C. Lipolysis, however, was generally strongest at 20 C or below.
Incorporation of Radioactive Acetate into Diacetyl by
Streptococcus diacetilactis
Authors: Speckman R. A. , Collins E. B.
Published: December 2020

Streptococcus diacetilactis
was grown in a partially defined, lipoic acid-free medium containing radioactive acetate with and without addition of 0.1% unlabeled sodium pyruvate. Labeled carbon was incorporated into diacetyl, but neither the amount of diacetyl produced nor its specific activity was influenced by addition of pyruvate. Acetoin had low specific activity, indicating that it was a mixture of radioactive and nonradioactive acetoin. The specific activity of acetoin was lower when pyruvate, a precursor of unlabeled acetoin, was added to the medium, which indicated that the radioactive acetoin was produced from radioactive diacetyl by diacetyl reductase. Results substantiate condensation of acetyl-coenzyme A with hydroxyethylthiamine pyrophosphate as the in vivo mechanism for synthesis of diacetyl.
Inactivation of Foot-and-Mouth Disease Virus with Ethylenimine
Authors: Cunliffe H. R.
Published: December 2020

Foot-and-mouth disease virus (FMDV) was inactivated by ethylenimine (EI) at three concentrations and two temperatures. Comparison of inactivation kinetics and the antigenic and immunogenic potency of EI and
N
-acetylethylenimine (AEI)-inactivated FMDV indicates that EI has nearly optimal characteristics as an inactivant for FMDV vaccine preparation. Although AEI-inactivated FMDV has proved to be a potent specific immunogen, an equivalent percentage of EI inactivated FMDV at substantially faster rates and produced an equally potent immunogen. In addition, EI inactivated FMDV at rates that were essentially linear throughout the loss of nearly all measurable infectivity.
Neural Disturbances in Chickens Caused by Dietary T-2 Toxin
Authors: Wyatt R. D. , Colwell W. M. , Hamilton P. B. , Burmeister H. R.
Published: December 2020

Graded concentrations of dietary T-2 toxin (0, 1, 2, 4, 8, and 16 μg/g) were fed to groups of 40 chickens. T-2 toxin was found to cause an abnormal positioning of the wings, hysteroid seizures, and impaired righting reflex in young chickens. The abnormal wing positioning occurred spontaneously or as the result of dropping from a height of 1 meter. The seizures could be elicited by rough handling or loud noises. The seizures and the abnormal wing posture would not occur again when the stimulus was repeated unless a rest period of 3 to 6 h was allowed. The loss of righting reflex could be demonstrated at any time. The total incidence of neural symptoms was dependent on the length of exposure to T-2 toxin and to its concentration. Neural toxicity occurred at dosages of 4, 8, and 16 μg per g of diet, which are the same doses that retard growth. This neural toxicity of T-2 toxin in chickens is similar to the neural disturbances associated with alimentary toxic aleukia, a nutritional toxicosis of humans produced by eating moldy grain. T-2 toxin has been implicated also in moldy corn toxicosis which has neural manifestations in horses and swine.