bluuebunny/crossref_metadata_2025 huggingface dataset:
Biosynthesis of Glutamic Acid in
Saccharomyces
: Accumulation of Tricarboxylic Acid Cycle Intermediates in a Glutamate Auxotroph
Authors: Crocker Wilson H. , Bhattacharjee J. K.
Published: December 2020

Aconitaseless glutamic acid auxotroph MO-1-9B of
Saccharomyces
grew in glutamic acid-supplemented minimal medium, but failed to grow when glutamic acid was substituted by proline, arginine, ornithine, or glutamine. This mutant was also unable to utilize lactate or glycerol as a carbon source. Under a glutamic acid-limiting condition, by using acetate-
1
-
14
C
as tracer, the mutant accumulated rather large amounts of
14
C-citric acid and
14
C-succinic acid when compared with the wild-type strain. Under excess glutamic acid supplementation, accumulation of citric acid and succinic acid was considerably reduced. When
14
C-glutamic acid-(U) was used as tracer,
14
C-α-ketoglutaric acid,
14
C-citric acid, and
14
C-succinic acid were accumulated in the mutant. The citric acid peak was the largest, followed by α-ketoglutaric acid and succinic acid. In the wild-type strain under similar conditions, only small amounts of
14
C-citric acid and
14
C-succinic acid and no
14
C-α-ketoglutaric acid were accumulated.
Staphylococcal Enterotoxins A and B: Solid-Phase Radioimmunoassay in Food
Authors: Johnson H. M. , Bukovic J. A. , Kauffmann P. E.
Published: December 2020

An immunoassay employing
125
I labeled enterotoxins A and B and polystyrene tubes coated with specific antibodies was used for detection and quantitation of enterotoxin in food. Ham salad, cheddar cheese, custard, condensed milk, and salami were studied. Enterotoxin was successfully determined in all the foods by simple extraction procedures. The assay was sensitive to 1 to 10 ng of toxin per g of food; nonspecific inhibitions were 15% or less.
Silica Gel Medium for Enumeration of Petroleumlytic Microorganisms in the Marine Environment
Authors: Seki Humitake
Published: December 2020

A silica gel medium was developed for the enumeration of petroleumlytic microorganisms in the marine environment. The medium was satisfactorily used for the investigation of the vertical distribution of bacteria in seawater from the surface to 1,000 m depth of western north Pacific central water as well as the neritic region of Japan.
Biodegradation of Phenylmercuric Acetate by Mercury-Resistant Bacteria
Authors: Nelson J. D. , Blair W. , Brinckman F. E. , Colwell R. R. , Iverson W. P.
Published: December 2020

Selected cultures of mercury-resistant bacteria degrade the fungicide-slimicide phenylmercuric acetate. By means of a closed system incorporating a flameless atomic absorption spectrophotometer and a vapor phase chromatograph, it was demonstrated that elemental mercury vapor and benzene were products of phenylmercuric acetate degradation.
Infectious Bovine Rhinotracheitis Virus Infection in Bulls, with Special Reference to Preputial Infection
Authors: Bitsch V.
Published: December 2020

In an experiment with infectious bovine rhinotracheitis (IBR) virus in two bulls, observed over a period of 122 weeks, the pattern of virus release was studied. Recurrent, unprovoked release of virus was demonstrated after one year in a nasal washing from one of the bulls and in preputial washings of both on 13 and 4 occasions, respectively, and finally in weeks 113 and 110, although clinical disease was not observed. During periods of recurrent virus release, concentrations of virus in the prepuce were generally much lower than during the period of primary infection; usually, however, they were not of negligible titer. The frequency of such periods and the virus titers observed strongly suggest that an IBR antibody carrier should always be considered as a potential source of infection to other animals. When virus was demonstrated in semen an almost equal amount was found in the preputial washing (50 ml). In week 120, virus replication in the respiratory tract and prepuce was induced in both bulls by prednisolone injections. It is concluded that antibody carriers will rarely attain a state of absolute immunity.
Trends in Wort Carbohydrate Utilization
Authors: Patel Girishchandra B. , Ingledew W. Michael
Published: December 2020

A gas chromatographic method suitable for any type of low-molecular-weight carbohydrate analysis has been utilized to determine the individual wort sugars in corn adjunct wort from a Western Canadian brewery. The fluctuations in each sugar during primary lager fermentation have been graphed. “End fermented” wort has been shown to contain some maltotriose, a small amount of maltose, and the nonfermentable carbohydrates, including maltotetraose, maltopentose, and dextrins.
Microbiological Evaluation of Suture Items Before Radiation Sterilization
Authors: Österberg Bertil O.
Published: December 2020

Microbiological contamination levels of suture samples taken at various stages of the manufacturing process in a new hygienically controlled plant were determined by employing a membrane filturation technique. Both raw material and materials handled manually in the production process were tested to assess the effect of manual handling on the product contamination level. Evaluation of the efficacy of contamination control, however, was directed primarily to the finished, packaged products, just prior to the processing with cobalt 60. The suture material for testing was divided into two groups, namely, wet and dry products, the wet being packaged in a special “tubing” fluid consisting mainly of isopropyl alcohol. Initial contamination results are reported as the average of values obtained on the test day and the preceding 9 consecutive production days. A total of 1,787 suture samples tested in the dry group showed daily averages varying between 2.1 and 14.8 contaminants per suture. The 2,980 wet-packaged suture samples tested gave daily averages varying from 0.7 to 4.2 contaminants per suture. The highest values obtained for an individual suture were 400 for the dry and 89 for the wet. Identification studies of the contaminants revealed that fungi predominated. Most of the bacterial contaminants proved to be spore-forming rods.
Evaluation of Radiometric System for Detecting Bacteremia
Authors: Renner Edward D. , Gatheridge Laurel A. , Washington John A.
Published: December 2020

An automated radiometric system (BACTEC, Johnston Laboratories) for detection of bacteremia was evaluated in parallel with a standard blood culture system in use in our laboratory. Of 1,445 blood cultures from 484 patients with possible bacteremia, 106 sets of cultures (excluding 39 presumed contaminated), representing 56 patients, were positive by both methods. The conventional system yielded 85 positive cultures from 48 patients, whereas the BACTEC system yielded 84 positive cultures from 43 patients. The BACTEC system failed to detect 22 cultures that were positive in the conventional system, and the conventional system failed to detect 21 cultures that were positive in the BACTEC system. The detection efficiency was generally equivalent in the two systems except for the lower detection rates of anaerobes and
Enterobacter aerogenes
by the BACTEC system and the lower detection rates of
Torulopsis glabrata
and, possibly,
Pseudomonas
sp. (group IVD) in the conventional system. The BACTEC system had a slight advantage over the conventional system in the time interval to detection of positivity. Approximately 20% of the positive cultures detected by the BACTEC system were detected on the first day of incubation compared with 7% by the conventional system. The recovery rates and detection times of anaerobes were less efficient by the BACTEC system than by the conventional system. It does not appear that the radiometric method has much advantage over available conventional methods.
Microtissue Culture Plaque Assay for
Herpesvirus saimiri
Authors: Chan Emerson W. , Dunkel Virginia C.
Published: December 2020

A microtissue culture method for the plaque assay of
Herpesvirus saimiri
has been developed. Virus titrations carried out in Microtest II tissue culture plates (Falcon) yielded reproducible results that agreed well with those obtained by employing macrocultures. The described method is quantitative, reproducible, economical, and suitable for routine assay of large numbers of virus samples.
Biodegradation of
o
-Benzyl-
p
-Chlorophenol
Authors: Swisher R. D. , Gledhill W. E.
Published: December 2020

The extent of biodegradation of
o
-benzyl-
p
-chlorophenol, marketed as a germicide under the name Santophen
®
1 (Monsanto Co.), in river water, sewage, and activated sludge was determined. Biodegradation was assessed by use of a colorimetric procedure for phenolic materials, carbon analysis, and CO
2
evolution. In unacclimated river water, 0.1 mg of Santophen 1 per liter was degraded within 6 days. In sewage, 0.5 and 1.0 mg/liter levels of Santophen 1 were degraded in 1 day. Acclimated activated sludge achieved 80% biodegradation of 1.0 mg/liter Santophen 1 in 8 h and 100% in 24 h. When effluent from a semicontinuous activated sludge unit, acclimated to 20 mg of Santophen 1 per liter was used as the inoculum for the CO
2
evolution procedure, 60% of the total theoretical CO
2
was evolved from Santophen 1. Based on the results of these studies, indicating Santophen 1 to be readily biodegraded in at least four biological systems, the continued use of present levels of Santophen 1 should present no significant environmental problems.
Quantitative Extraction of Adenosine Triphosphate from Cultivable and Host-Grown Microbes: Calculation of Adenosine Triphosphate Pools
Authors: Dhople Arvind M. , Hanks John H.
Published: December 2020

Existing data on adenosine triphosphate (ATP) pools in microbes are deficient for two reasons: (i) incomplete extractions of ATP, and (ii) the failure to take into account that the adverse effects of extracting procedures on standard ATP exert analogous effects on the ATP released from bacterial cells. Methods for correcting observed yields and calculating ATP pools have been demonstrated. Three bacterial species were used in the studies on extraction of ATP:
Escherichia coli, Mycobacterium phlei
, and
Mycobacterium lepraemurium
. Perchloric acid and n-butanol were disqualified because of their failure to extract total bacterial ATP even from
E. coli
and because of inconvenient procedures. The new extraction procedure had minimal effects on standard ATP, liberated 100% of the ATP pools from the three representative species of microbes, and caused no ionic imbalance or quenching of bioluminescence. This method involves vortexing of cell suspensions for 10 s with 23% chloroform (vol/vol), heating at 98 C for the required time (
E. coli
, 3 min;
M. phlei
, 5 min;
M. lepraemurium
, 10 min) and then 1 min at 98 C with vacuum to dry the samples. Heat or chloroform alone may suffice for some microbes and release total ATP from plant and animal cells.
Lytic Activity of Vibrio Phages on Strains of
Vibrio fetus
Isolated from Man and Animals
Authors: Bryner John H. , Ritchie A. E. , Booth G. D. , Foley J. W.
Published: December 2020

Five phages isolated from lysogenic strains of
Vibrio fetus
var.
venerealis
and two from
V. fetus
var.
intestinalis
were tested for lytic activity on 95
V. fetus
strains from various animal and human hosts. In addition, virion and plaque morphology of the seven phages were compared. Electron micrographs showed that all were the kite-tailed variety with minor variations in head and tail dimensions. Plaques of V45 and V2 were small, clear and irregular; those of V3, V8, and V19 were large, clear and regular at the edge; the plaques of V16 and V20 were intermediate in size, clear, and very irregular at the edge with satellite plaques. The number of strains lysed by one or more phages were as follows: 29 of 30 from cattle; 7 of 11 from sheep; 1 of 5 from pigs; 1 of 1 from a monkey; and 33 of 42 from human hosts. Four natural groups of phages were derived by statistical measures of percentage of similarity in lytic activity. Group III lysed more strains (46 of 95) than any of the others. Twenty-five strains were lysed by group IV, 23 strains by group I, and 19 strains by group II. Results of this study indicate that phage typing should be a practical supplement to other differential tests for
V. fetus
.
Cultivation of Mycoplasmas on Cellulose Ester Substrates
Authors: Gabridge Michael G.
Published: December 2020

The ability of mycoplasmas to grow on cellulose ester substrates was evaluated.
Mycoplasma pneumoniae, M. hominis, M. arthritidis, M. gallisepticum
, and
Acholeplasma laidlawii
grew on Millipore (mixed cellulose ester) filters and Sepraphore III (cellulose polyacetate) membranes.
Clinical Evaluation of Sodium Amylosulfate in Human Blood Cultures
Authors: Kocka F. E. , Arthur Elizabeth J. , Searcy R. L. , Smith Merrily , Grodner Barbara
Published: December 2020

Sodium amylosulfate was shown to be a useful anticoagulant additive for increased isolation of bacteria from clinical blood cultures.
Evaluation of the Interference Filter for Use in Rabies Diagnosis by the Fluorescent Antibody Test
Authors: Lewis Vester J. , Thacker W. Lanier , Engelman Helen M.
Published: December 2020

When compared with primary filters widely used for rabies diagnosis by the fluorescent antibody test, an interference filter markedly increased specific staining intensity and contrast.
Enhancement of Interferon Production in a Mouse Cell Line, a High-Yielding Source of Mouse Interferon
Authors: Edy Victor G. , Billiau Alfons , De Somer Pierre
Published: December 2020

Priming with interferon prior to poly(I)·poly(C) treatment of a mouse cell line, MO 57/2, followed by sequential administration of metabolic inhibitors, resulted in the production of high yields of mouse interferon.
Temperature Adaptability of Psychrotrophic
Pseudomonas
Authors: Zachariah Prince , Liston John
Published: December 2020

The rate of oxidation of glucose and alanine at low temperatures by washed cells of psychrotrophic strains of
Pseudomonas
is related to growth temperature.
Novel Technique for Isolating Microstructures Present in Shake Cultures of the Fungus
Ceratocystis ulmi
Authors: Richards Wayne C. , Takai Shozo
Published: December 2020

Microstructures found in shake cultures of
Ceratocystis ulmi
, the fungus causing Dutch elm disease, have been isolated by a novel technique using the effect of bubbling gas through the culture filtrate.
2, 4-Dichlorophenoxyacetate Metabolism by
Arthrobacter
sp.: Accumulation of a Chlorobutenolide
Authors: Sharpee K. W. , Duxbury J. M. , Alexander M.
Published: December 2020

An enzyme preparation from 2,4-dichlorophenoxyacetate-grown
Arthrobacter
sp. converted
cis,cis
-2,4-dichloromuconate to chloromaleylacetate. The enzyme lactonizing the dichloromuconate to yield 2-chloro-4-carboxymethylene but-2-enolide was separated from the butenolide-delactonizing enzyme.
Susceptibility of the Mouse Intestine to Heat-Stable Enterotoxin Produced by Enteropathogenic
Escherichia coli
of Porcine Origin
Authors: Dobrescu Lucia , Huygelen C.
Published: December 2020

Ligated intestinal loops of mice were found suitable for the assay of heat-stable enterotoxin produced by enteropathogenic
Escherichia coli
strains of porcine origin; loops inoculated with heat-labile enterotoxin failed to react.
Efficiency of Various Growth Media in Recovering Oral Bacterial Flora from Human Dental Plaque
Authors: Syed Salam A. , Loesche Walter J.
Published: December 2020

MM10 sucrose blood agar (MM10 SB agar), N
2
C agar, Schaedler agar (SH agar), and mitis salivarius agar (MS agar) were tested for their ability to recover human dental plaque flora by a continuous anaerobic procedure and by a conventional anaerobic method. MM10 SB agar yielded higher recovery of bacteria from plaque samples as determined by the enumeration of colony-forming units (CFU). The CFU on N
2
C agar, SH agar, and MS agar were lower than MM10 SB agar when the continuous anaerobic procedure was used. The superior performance of MM10 SB agar was much more apparent when used for the cultivation of dental plaque by the conventional anaerobic method. Under these conditions the counts were consistently higher on MM10 SB agar as compared to the other media tested. However, the differential counts of
Streptococcus sanguis
and
S. mutans
from carious plaque samples were in general comparable on all culture media. Deletion of blood from MM10 SB agar did not lower counts. The elimination of dithiothreitol from this medium resulted in a significantly lower recovery of bacteria from the plaque samples when cultured by the conventional anaerobic method. The storage of MM10 SB agar for varying periods of time aerobic conditions did not seem to affect its performance. These findings suggest that MM10 SB agar is an ideal culture medium for the isolation, nonselective enumeration, and differential counts of bacteria present in normal and disease-associated plaques.
Comparison of Atmospheric Conditions for Culture of Clinical Specimens of
Neisseria gonorrhoeae
Authors: James-Holmquest Ann N. , Wende Reuben D. , Mudd Robie L. , Williams Robert P.
Published: December 2020

We cultured 55 clinical specimens of
Neisseria gonorrhoeae
in the following atmospheric conditions: (i) 10% carbon dioxide in a CO
2
incubator; (ii) a candle extinction jar; (iii) an air convection incubator; and (iv) an anaerobic jar without added CO
2
. The number and size of colonies growing on modified Thayer-Martin medium were evaluated after incubation of cultures for 24 and 48 h at 36 C. After 24 h, the specimens from the candle extinction jar had the greatest number and size of colonies, but after 48 h growth was approximately equal for specimens from the candle jar and the CO
2
incubator. Only 19 of 55 specimens grew in the air convention incubator. None of 55 clinical specimens or of 10 laboratory strains grew anaerobically. Development of colonial morphology for colony types 1, 2, 3, and 4 was studied at 24 h on a base medium that contained no hemoglobin. The relative numbers of the four colony types in specimens were comparable after 24 h of incubation in any of the three atmospheric conditions under which growth occurred, but the different types were distinguished most readily when grown in the candle extinction jar.
Microtiter Solid-Phase Radioimmunoassay for Hepatitis B Antigen
Authors: Purcell Robert H. , Wong Doris C. , Alter Harvey J. , Holland Paul V.
Published: December 2020

A micro-solid-phase radioimmunoassay (micro-SPRIA) for hepatitis B antigen (HB Ag) was developed for use with microtiter serological equipment. Radiolabeled immunoglobulin G was prepared from human and animal sera containing hepatitis B antibody (HB Ab); it was not necessary to isolate specific HB Ab by immunochemical means. A micro-SPRIA prepared with guinea pig reagents was approximately as sensitive as the AusRIA radioimmunoassay, but, like the AusRIA test, yielded false positive results. A micro-SPRIA prepared with human reagents was slightly less sensitive but did not yield false positive results. These micro-SPRIA tests offer several advantages, including conservation of reagents, adaptability to other antigen-antibody systems, ease of performance (especially when testing large numbers of specimens), and economy.
Possible Evidence for Interference with Venezuelan Equine Encephalitis Virus Vaccination of Equines by Pre-Existing Antibody to Eastern or Western Equine Encephalitis Virus, or Both
Authors: Calisher Charles H. , Sasso Donna R. , Sather Gladys E.
Published: December 2020

During 1971, an epizootic of Venezuelan equine encephalitis (VEE) reached the United States. Laboratory tests were performed on a large number of sick, healthy, unvaccinated, and vaccinated horses. Neutralization (N) tests in cell cultures revealed that 153 of 193 (79.3%) equines outside the state of Texas and 175 of 204 (85.8%) within Texas (82.6% overall) had detectable N antibody to VEE virus a week or more after vaccination. Twenty-six of 40 (65%) non-Texas equines and 18 of 29 (62%) Texas equines which had no detectable antibody against VEE virus a week or more after vaccination had N antibody against Eastern equine encephalitis (EEE) or Western equine encephalitis (WEE) virus or both, whereas only 50 of 153 (32.7%) non-Texas equines and 82 of 175 (46.9%) Texas equines with demonstrable N antibody against VEE also had N antibody against EEE and/or WEE virus. In vaccinated equines, significant negative correlations were found between the occurrence of antibody to VEE and antibody to EEE and/or WEE virus. These findings support the hypothesis that pre-existing antibody to EEE and/or WEE virus may modify or interfere with infection by VEE virus. The epizoologic significance of this possibility is discussed briefly.
Microbiology of Lebanon Bologna
Authors: Smith James L. , Palumbo Samuel A.
Published: December 2020

Various aspects of the microbiology of the Lebanon bologna process were studied. Manufacture of Lebanon bologna appeared to be similar to that of summer sausage and other fermented sausages and consisted of a lactic acid fermentation by lactobacilli accompanied by the production of cured meat color from the reduction of nitrate by micrococci. The traditional process consists of aging coarse ground beef at 5 C for several days. Aging the beef for about 10 days was necessary to allow development of lactic acid bacteria; for successful fermentation, the concentration of lactic acid producers must be 10
4
/g or more. At least 3% NaCl was necessary to suppress the development of pseudomonads during the aging period; higher concentrations of salt suppress the development of the lactic acid-producing flora. During aging, in the presence of salt, the predominant flora developing on the meat consisted of catalase-positive, gram-positive rods and cocci; during fermentation at 35 C, the predominant flora became catalase-negative, gram-positive rods with characteristics of lactobacilli. Lebanon bologna could be made from frozen beef if the meat was thawed, salted, and aged. However, bolognas could not be made from unaged beef unless a lactic acid starter culture was used. The microflora of several commercial bolognas is reported also.
Comparison of Methods for the Recovery of Virus Inoculated into Ground Beef
Authors: Tierney John T. , Sullivan Robert , Larkin Edward P. , Peeler James T.
Published: December 2020

Various methods for the recovery of virus inoculated into ground beef were investigated in an attempt to develop a sensitive system that could be used to detect viral contaminants in market foods. A 100-g sample, inoculated with poliovirus 1, was suspended in 150 to 900 ml of Eagle minimum essential medium, pH 8.5, and mixed in either plastic bags or plastic cups on a mechanical shaker. The particulate materials were removed by means of cheese cloth, glass wool, woven fiber glass, or low-speed centrifugation. Large volumes of fluid were concentrated by ultrafiltration. Microbiological contamination was controlled by high antibiotic concentrations or by filtration. Quantitative plaque-forming-unit recovery of the virus was determined by utilizing an agar overlay technique on Vero cell cultures. The data indicated that from 20 to 50% of the seeded virus could be recovered from a 100-g sample of ground beef. The glass wool and woven fiber glass methods were the most effective, with recovery of approximately 50% of the inoculated virus.
Use of Coating to Protect Lyophilized
Bacillus popilliae
from Moisture
Authors: Cloran Jean , McMahon K. J.
Published: December 2020

Lyophilized cells of
Bacillus popilliae
were protected from moisture when suspended in pellets of tung oil polymer which were then coated with paraffin wax. The survival of the protected cells at various levels of relative humidity (RH) and under various storage conditions was determined. During 6 months of storage, moisture appeared to have little effect on survival of the cells when the RH level was 22% or less; but, at higher RH levels, survival declined upon storage. Viable cells were recovered when pellets were stored for 3 months at 33% RH, 2 months at 42% RH, 1 month at 50% RH, and 4 days in distilled water. Under field conditions, some cells survived at least 1 week of storage.
Plating Efficiency for Primary Hamster Embryo Cells as an Index of Efficacy of Fetal Bovine Serum for Cell Culture
Authors: Goodheart C. R. , Casto B. C. , Zwiers A. , Regnier P. R.
Published: December 2020

Attachment and growth of mammalian cells plated at low cell density require optimum conditions for the cells to form colonies. Reliability, reproducibility, and validity of the plating efficiency test for evaluating cell culture sera were determined by measuring the plating efficiency of 37 lots of fetal bovine serum obtained from 8 suppliers (5 lots from each of 7, 2 lots from 1 supplier), by using hamster embryo fibroblasts plated at low cell density. The test revealed considerable variation between lots of serum and between suppliers. The five lots from some suppliers had consistently high plating efficiencies, whereas one or more lots from other suppliers had quite low efficiencies. The results were reproducible in repeated tests, and control experiments indicated that the test measured the efficiency of the test serum independently of the efficiency of the serum used for the primary outgrowth of the hamster embryo cells.
Effectiveness of Septisol Antiseptic Foam as a Surgical Scrub Agent
Authors: Dewar Norman E. , Gravens Daniel L.
Published: December 2020

Septisol antiseptic foam (0.23% hexachlorophene in a 46% ethyl alcohol base) is a new surgical scrub agent for both primary and re-entry use that is designed to minimize the harsh effects to the skin of the conventional scrub while retaining effective antibacterial properties. A preliminary surgical scrub study of 1-week duration yielded an immediate reduction in resident flora of 92% from an average single scrub coupled with a residual bacteriostatic effect from repeated use that gave a plateau at 57% of the pretest resident population level. A separate study demonstrated complete elimination of both gram-positive and gram-negative transients from the skin with a single application of the product. In an 8-week surgical scrub study, equal effectiveness was shown between Septisol antiseptic foam and a standard 3% hexachlorophene detergent. However, Septisol antiseptic foam offers considerable advantage in minimizing the harsh effects to the skin of the conventional surgical scrub and results in a substantially lower hemic level of hexachlorophene in the user than that obtained with 3% hexachlorophene detergent. Sampling was conducted by the fingerprint impression plate technique of Gale.
Chlamydia trachomatis
in Cell Culture. I. Comparison of Efficiencies of Infection in Several Chemically Defined Media, at Various pH and Temperature Values, and After Exposure to Diethylaminoethyl-Dextran
Authors: Rota Teresa Rondon , Nichols Roger L.
Published: December 2020

Three chemically defined cell culture media, Eagle minimum essential medium (MEM) with Earle basal salt solution, Eagle MEM with Hanks basal salt solution, and a modified Eagle MEM, were tested and found capable of supporting the development of
Chlamydia trachomatis
in
60
Co-treated McCoy cells. The enhancement of trachoma infection by diethylaminoethyl-dextran (DEAE-D) was greater at pH values closer to neutrality than at any other pH values measured at the start of the experiments. Centrifugation of the trachoma inoculum onto cell monolayers at 33 C increased the number of inclusions when compared to centrifugation at 20 C. When the inoculum was centrifuged onto cell monolayers and subsequent incubation was at temperatures ranging from 34 to 39 C, the greatest number of inclusions was observed after incubation from 35 through 37 C. Enhancement of the trachoma infection by DEAE-D was tested at temperatures ranging from 35 to 37 C. These cultures had three- to fivefold increases in inclusions when compared to previously reported experiments in which DEAE-D-treated cultures were incubated at 34 C.
Equine Abortion (Herpes) Virus: Evaluation of Markers in a Field Vaccination Trial
Authors: Klingeborn Berndt
Published: December 2020

Twelve mares were vaccinated with attenuated equine abortion virus (EAV) strain RAC-H. Two nonvaccinated mares served as controls. In at least three mares the vaccination appeared to coincide with a natural infection. This was indicated by characterization of the EAV isolated from nasal secretions of six vaccinated mares, a nonvaccinated control, and also from the lung, spleen, and liver of a fetus aborted by a vaccinated mare. The relative sensitivity of the isolated EAV to dithiothreitol was used to distinguish the RAC-H strain and wild-type virus. Of the 10 EAV isolates, four were recognized as being the vaccine strain while six were recognized as being wild-type strains. Three of the latter originated from two vaccinated mares and a nonvaccinated control, and three were recovered from the fetus. The ability of the EAV strains to form plaques in a cloned line of L cells proved to be unsuitable for use as a marker in this study.
Storage of Brewing Yeasts by Liquid Nitrogen Refrigeration
Authors: Wellman A. M. , Stewart G. G.
Published: December 2020

Many yeast strains are difficult to maintain in culture in a stable state, and long-term preservation by lyophilization, which has proved useful for other fungi, has given poor results with brewing yeasts. As an alternative to continuous subculture, which maximizes strain variability, various methods of cryogenic storage were investigated. Yeast strains were frozen with or without cryoprotectants (such as glycerol or inositol) and stored at -196 C. Recovery after warming was estimated from plate counts, and survivors were screened to detect changes in the frequency of morphological types, respiratory-deficient mutants, and glycerol-sensitive mutants. Strains varied in their sensitivity to freezing, and survival was modified by the growth medium, the freezing munstrua, and the freezing conditions. Suspension of cells in 10% (vol/vol) glycerol, cooled at 1 C/min, warmed rapidly and plated on malt-yeast extract-glucose-peptone agar produced the highest percentage of viable colonies with a minimal change in metabolic characteristics. In two of the strains tested, no significant increase in mutation rate was detected under any of the treatments; the strains were maintained in a stable state and were metabolically comparable to unfrozen strains. In one strain of
Saccharomyces uvarum
after some freezing treatments, the percentage of respiratory-deficient mutants increased markedly, the fermentation rate declined, and a loss of flocculation occurred. The freezing parameters which increased the level of respiratory-deficient cells should be avoided in maintaining this strain. Maintenance of cultures of brewing yeasts by cryogenic storage has several advantages over other preservation techniques: the method is simple and reproducible, the cultures have remained stable over a 3-year test period, and the viability is high.
Use of Combusted Natural Gas to Cultivate the Anaerobic Bacterial Flora from the Cecum Contents of Mice
Authors: Koopman J. P. , Van Oeveren J. P. , Janssen F. G. J.
Published: December 2020

The use of combusted natural gas as atmosphere for cultivation of the anaerobic bacterial flora from the cecum of mice is described. The combusted gas (inert gas) continuously flushes a glove box in which it is possible to cultivate a number of strict anaerobes from the cecum of mice.
Sporicidal Properties of Hydrogen Peroxide Against Food Spoilage Organisms
Authors: Toledo R. T. , Escher F. E. , Ayres J. C.
Published: December 2020

The sporicidal properties of hydrogen peroxide were evaluated at concentrations of 10 to 41% and at temperatures of 24 to 76 C. The organisms tested and their relative resistance at 24 C to 25.8% H
2
O
2
were:
Bacillus subtilis
SA 22 >
B. subtilis
var.
globigii
>
B. coagulans
>
B. stearothermophilus
>
Clostridium
sp. putrefactive anaerobe 3679 >
S. aureus
, with “D” values of 7.3, 2, 1.8, 1.5, 0.8., and 0.2 min, respectively. Heat shocking spores prior to hydrogen peroxide treatment decreased their resistance. Wet spores were more resistant than dry spores when good mixing was achieved during hydrogen peroxide treatment. Inactivation curves followed first-order kinetics except for a lag period where the inactivation rate was very slow. Increasing the H
2
O
2
concentration and the temperature reduced the lag period.
Sorption Processes in Gas Sterilization in the Medical Sector
Authors: Jordy A. , Suhr H.
Published: December 2020

Sorption of ethylene oxide during and after gaseous sterilization is influenced by numerous factors. It was found that ethylene oxide desorption not only depends on material to be fumigated but also to a considerable degree on the wrapping material. Although polyethylene, polyamide (nylon), polytetrafluoroethylene (Teflon), silicone, aluminum, and glass beads contained no quantities of ethylene oxide detectable by gas chromatography after 72 h of aeration, residual amounts were definitely determined, even after 76 h of aeration in polypropylene, polystyrene, polyvinylchloride, paper products, and compound products of various plastics and paper mixtures. Desorption was, in all cases, found to be better when a mixture of ethylene oxide and methyl formate was used instead of pure ethylene oxide.
Bacillus
sp. ATCC 27380: a Spore with Extreme Resistance to Dry Heat
Authors: Bond Walter W. , Favero Martin S. , Korber Marilyn R.
Published: December 2020

An unusual mesophilic
Bacillus
sp. was isolated from heated soil, and a cleaned spore preparation showed extraordinary resistance to dry heat (
D
125C
= 139 h) and relative sensitivity to moist heat (
D
80C
= 61 min). Biochemical tests and morphology fit no described species.
Microcomplement-Fixation Inhibition: a Rapid and Economical Test to Detect Non-Complement-Fixing Antibodies
Authors: Olsen Richard G. , Mathes Larry E. , Yohn David S.
Published: December 2020

Complement-fixation inhibition test was adapted to the microtiter system. When cat and monkey non-complement-fixing antibody were used, the microtest was shown to be as sensitive as the conventional tube complement-fixation inhibition test.
Growth and Virulence of
Salmonella typhimurium
Grown in Different Foods
Authors: Idziak Edmund S. , Crossley Karen
Published: December 2020

Experimental data indicate that the virulence of
Salmonella typhimurium
grown in different foods varies. The possibility exists, therefore, that ingestion of foods containing the same number of salmonellae may not constitute a similar health hazard.
Production, Isolation, and Preliminary Toxicity Studies of Brevianamide A from Cultures of
Penicillium viridicatum
Authors: Wilson Benjamin J. , Yang Dominic T. C. , Harris Thomas M.
Published: December 2020

Brevianamide A, one of a novel group of alkaloids first obtained from
Penicillium brevi-compactum
, has also been isolated as a principal metabolite from two key isolates of
P. viridicatum
. Procedures for bioproduction and purification are described. This compound was not toxic when fed or injected into mice and had no antibiotic properties against several common bacterial and fungal microorganisms. Brevianamides A and B are among at least four yellow metabolites that may be formed by isolates of
P. viridicatum
.
Isolation of Group H Streptococcal Competence Factor
Authors: Perry Dennis
Published: December 2020

Competence factor (CF) was purified 600-fold from culture filtrates of competent group H streptococcus, strain Challis, by fractionation on a carboxymethyl-Sephadex column. The preparation did not contain orcinol- or diphenylamine-positive material, and CF activity was destroyed by trypsin. An examination of its chemical composition revealed 10 amino acids, muramic acid, glucosamine, and glucose.
Formation of Extracellular C
14
-C
18
2-D-Hydroxy Fatty Acids by Species of
Saccharomycopsis
Authors: Kurtzman C. P. , Vesonder R. F. , Smiley M. J.
Published: December 2020

Eighteen of 19 strains of
Saccharomycopsis fibuligera
and one of two strains of
S. capsularis
produced mixtures of C
14
-C
18
2-D-hydroxy acids in liquid culture medium. The mixture of these acids showed antimicrobial activity against
Vibrio tyrogenus
but not against the other microorganisms tested.
Candida lactosa
, a recently described species, was shown to be an isolates of
S. fibuligera
.
Development and Evaluation of a Direct Fluorescent Antibody Method for the Diagnosis of
Pneumocystis carinii
Infections in Experimental Animals
Authors: Lim Sook Kyung , Eveland Warren C. , Porter Richard J.
Published: December 2020

Because no fully satisfactory diagnostic method has been available for use in pneumocystis infection, an attempt was made to apply the fluorescent antibody technique in the identification of
Pneumocystis carinii
. Hyperimmune sera were prepared in rabbits against
P. carinii
from human and rat sources. After proper adsorption, these antisera were conjugated with fluorescein isothiocyanate and used as reagents in a direct fluorescent antibody procedure. Each of the two reagents was found to stain trypsin-treated
P. carinii
organisms from either human or rat sources, indicating the presence of common antigens. Stained organisms were demonstrated in the hypopharyngeal material from rats in which pneumocystis infection had been activated by the administration of corticosteroid. From the results reported here, the procedure outlined is considered sufficiently sensitive and specific to justify tests on pneumocystis infections in man. The findings in a series of specimens from human subjects will be reported separately. The method also provides an extended approach to related research problems. The need for controls of the procedure at all points is emphasized.
Growth of
Clostridium perfringens
in Food Proteins Previously Exposed to Proteolytic Bacilli
Authors: Schroder D. J. , Busta F. F.
Published: December 2020

Proteolytic sporeforming bacteria capable of surviving processing heat treatments in synthetic or fabricated protein foods exhibited no antagonistic effects on growth of
Clostridium perfringens
, but instead shortened the lag of subsequent growth of
C. perfringens
in sodium caseinate and isolated soy protein.
Bacillus subtilis
A cells were cultured in 3% sodium caseinate or isolated soy protein solutions. The subsequent effect on the lag time and growth of
C. perfringens
type A (strain S40) at 45 C was measured by colony count or absorbance at 650 nm, or both.
B. subtilis
incubation for 12 h or more in sodium caseinate reduced the
C. perfringens
lag by 3 h. Incubation of 8 h or more in isolated soy protein reduced the lag time by 1.5 h. Molecular sieving of the
B. subtilis
-treated sodium caseinate revealed that all molecular sizes yielded a similar reduced lag time. Diethylaminoethyl-Sephadex ion exchange fractionation and subsequent amino acid analysis indicated that the lag time reduction caused by
B. subtilis
incubation was not related to charge of the peptides nor to their amino acid composition. Apparently the shortened
C. perfringens
lag in these
B. subtilis
-hydrolyzed food proteins was a result of the protein being more readily available for utilization by
C. perfringens
.
Purification and Properties of an Aryl Acylamidase of
Bacillus sphaericus
, Catalyzing the Hydrolysis of Various Phenylamide Herbicides and Fungicides
Authors: Engelhardt G. , Wallnöfer P. R. , Plapp R.
Published: December 2020

From
Bacillus sphaericus
ATCC 12123 an aryl acylamidase (EC 3.5.1.13) was purified to homogeneity by ion exchange chromatography, gel filtration, and polyacrylamide gel electrophoresis. The enzyme is inducible by various phenylamides of the acylanilide, phenylcarbamate, and methoxysubstituted phenylurea type. It has a molecular weight of 75,000. Enzyme activity was inhibited by sulfhydryl reagents, several metal ions, and 3,4-dichloroaniline (a product of linuron degradation). A requirement for divalent metal ions in enzyme activity could not be demonstrated. In the presence of 6 M urea an irreversible inactivation of the enzyme occurred. The hydrolysis of L-alanine-4-nitroanilide was competitively inhibited by puromycin.
Evaluation of a Fluorescent Antibody-Enrichment Serology Combination Procedure for the Detection of Salmonellae in Condiments, Food Products, Food By-Products, and Animal Feeds
Authors: Hilker John S. , Solberg Myron
Published: December 2020

The reliability of the enrichment serology (ES), fluorescent antibody (FA), and a combination of the FA and ES procedures for the detection of salmonellae were compared to the
Salmonella
cultural procedure outlined in the U.S. Food and Drug Administration's
Bacteriological Analytical Manual
(BAM). A total of 126 subsamples from 22 different products were analyzed. By utilizing the BAM procedure as the reference standard, a total of 66 samples were positive for salmonellae. Within 44 h approximately 65% of the
Salmonella
-negative samples could be cleared by the FA test. At the end of 50 h 97% of the
Salmonella
-negative samples could be cleared by the combination FA-ES test. The FA procedure detected all 66 BAM positives but exhibited a high incidence of presumptive positives which were cultural negatives. The ES procedure detected 64 of the 66 BAM positives but exhibited a low incidence of presumptive positives which were cultural negatives. Incorporating positive FA and positive ES results in a combination FA-ES technique revealed that FA-ES positives were statistically equivalent to BAM positives.
Effect of Propylene Oxide Treatment on the Microflora of Pecans
Authors: Blanchard Robert O. , Hanlin Richard T.
Published: December 2020

Studies were conducted to determine the effectiveness of propylene oxide (PO) treatment in controlling the microflora of pecans. As used commercially, PO has little effect on internal bacteria and fungi in pecan halves. Tests of surface washings of commercially treated pecans showed a reduction of 96% in coliform bacteria following PO treatment. Under controlled laboratory conditions, PO gave 80 to 92% reduction of surface microflora and at least 64% reduction of internal flora, but neither bacteria nor fungi could be eliminated completely, even with high dosages. Current assay methods for determining bacterial content of nutmeats were shown to be inadequate because they utilize only surface washings and thus do not give an accurate picture of the total bacterial population of the nutmeat. Consequently, such assays do not permit an accurate assessment of any potential health hazard related to these organisms.
α-Galactosidase Activity of Lactobacilli
Authors: Mital B. K. , Shallenberger R. S. , Steinkraus K. H.
Published: December 2020

α-Galactosidase (EC 3.2.1.22) activity was observed in cell-free extracts of
Lactobacillus fermenti, L. brevis, L. buchneri, L. cellobiosis
, and
L. salivarius
subsp.
salivarius
. The cultural conditions under which the enzyme activity was detected suggest that the enzyme is constitutive and present in the soluble fraction in the cell. The enzyme preparations readily hydrolyzed melibiose and other oligosaccharides containing α(1 → 6) linked galactose. Although the cell-free extracts of
L. fermenti
and
L. brevis
are negative for β-fructofuranosidase (EC 3.2.1.26), they hydrolyzed melibiose, stachyose, and raffinose in decreasing order of activity. The β-fructofuranosidase-positive
L. buchneri, L. cellobiosis
, and
L. salivarius
preparations hydrolyzed melibiose, raffinose, and stachyose in decreasing rates of activity. The α-galactosidases from different lactobacilli showed optimum activity in pH range 5.2 to 5.9.
L. fermenti
and
L. salivarius
preparations exhibited maximum activity between 40 to 44 C and 48 to 51 C, respectively, whereas a 38 to 42 C range was observed for other lactobacilli. Cell-free extract of
L. cellobiosis
was studied for transgalactosylase activity. When incubated with melibiose, a new compound was detected and tentatively identified as manninotriose.
Diacetyl, Acetoin, and Acetaldehyde Production by Mixed-Species Lactic Starter Cultures
Authors: Walsh B. , Cogan T. M.
Published: December 2020

Citrate utilization and acetoin, diacetyl, acetaldehyde, and lactic acid production in milk at 21 C by five different mixed-strain starters, containing
Streptococcus diacetilactis
(D type),
Leuconostoc
(B type), and
S. diacetilactis
and
Leuconostoc
(BD type), were measured. BD and D cultures utilized citrate more rapidly and produced more diacetyl, acetoin, and acetaldehyde than B types. All cultures produced much more acetoin than diacetyl, with the BD and D cultures producing four to five times larger amounts of acetoin than the B cultures. Reduction of diacetyl and acetoin toward the end of the normal incubation period was characteristic of BD and D cultures, whereas a similar reduction of acetaldehyde was characteristic of BD and especially of B cultures. Continued incubation of B cultures beyond 17 h also resulted in reduction of diacetyl and acetoin. Addition of citrate to the milk retarded diacetyl and acetoin reduction. Mn
2+
had no effect on diacetyl production by a BD culture but increased citrate utilization and, as a consequence, caused greater diacetyl destruction in one of the B cultures.
New Toxin from
Aspergillus flavus
Authors: Kirksey J. W. , Cole R. J.
Published: December 2020

Two nonaflatoxin-producing isolates of
Aspergillus flavus
produced a new nonfluorescent nitrogen-containing metabolite that was highly toxic to 1-day-old cockerels. The oral mean lethal dose of toxin was 19 mg/kg. Chemical and physical data obtained on the purified toxin demonstrated that it was not one of the previously reported metabolites of
A. flavus
. The common name “flavutoxin” has been assigned to the toxin.
β-Propriolactone Sterilization of Commercial Trypsin
Authors: Croghan D. L. , Matchett A.
Published: December 2020

A method for sterilizing commercial 1:250 trypsin was investigated.
Intravenous Catheter-Associated Bacteremia: Role of the Diagnostic Microbiology Laboratory
Authors: Crossley Kent , Matsen John M.
Published: December 2020

A 2-year review of 316 routine intravenous catheter cultures revealed 57 positive cultures (18%), with 57% of the 74 organisms recovered interpreted as pathogens. There were five episodes of catheter-associated septicemia.
Isolation of the Emetic Principle from
Fusarium
-Infected Corn
Authors: Vesonder R. F. , Ciegler A. , Jensen A. H.
Published: December 2020

A mycotoxin responsible for vomiting in swine has been isolated from
Fusarium
-contaminated field corn. The compound was tentatively identified as a trichothecene, 3,7,15-trihydroxy-12,13-epoxy-trichothe-9-en-8-one, and has been given the trivial name vomitoxin.
Multipurpose Medium for Use with
Pseudomonas
Species
Authors: Rosenthal Samuel L.
Published: December 2020

A medium is described which can be used to detect starch hydrolysis, gelatinase production, and denitrification by pseudomonads.
New Strain of
Yersinia enterocolitica
Pathogenic for Rodents
Authors: Carter Philip B. , Varga C. Francis , Keet Ernest E.
Published: December 2020

A strain of
Yersinia enterocolitica
, biotype 2, serotype 8, isolated from the blood of a human patient has been found to be highly pathogenic for rodents.
Effect of pH, Sodium Chloride, and Sodium Nitrite on Enterotoxin A Production
Authors: Tompkin R. B. , Ambrosino J. M. , Stozek S. K.
Published: December 2020

The combined effects of pH, sodium chloride, and sodium nitrite were studied by using a dialysis sac technique in brain heart infusion broth. Growth and enterotoxin A production by
Staphylococcus aureus
strain 100 were found to decrease with the addition of sodium nitrite, with a decrease in pH from 7.0, and with an increase in sodium chloride concentration. The significance of these results is discussed in relation to cured meats.