bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Environmental Factors on the Survival of Airborne T-3 Coliphage
Authors: Ehrlich Richard , Miller Sol , Idoine L. S.
Published: December 2020

Experiments were conducted to determine the effects of storage temperatures, relative humidity, and additives on the survival of aerosolized
Escherichia coli
phage T-3. The aerosol stability of the coliphage, calculated as per cent recovery, was not affected by storage at 10 or -70 C for up to 4 months. However, an increase in aerosol decay rate of coliphage stored at 10 C was observed. The effect of humidities ranging from 20 to 90% relative humidity was studied, and it was observed that humidities lower than 70% relative humidity significantly reduce the survival of airborne coliphage. The effect of various compounds on the aerosol decay rate of T-3 coliphage was studied at 50 and 85% relative humidity. Addition of dextrose in 0.1 M concentrations to the disseminating fluid significantly reduced aerosol decay rate at 50% relative humidity without affecting the decay at 85%. Addition of spermine, spermidine-phosphate, thiourea, galacturonic acid, and glucosaminic acid, individually or in combination, had no effect on aerosol decay rates. The use of deuterium oxide as the suspending fluid for dissemination had no effect on aerosol stability of the coliphage.
Studies on Bacterial Pyrogenicity
Authors: Martin William J. , Marcus Stanley
Published: December 2020

The specificity of the first or “presumptive” portion of the USP rabbit pyrogen test was investigated by use of a new absolute standard of reference. The reference standard was a 0.9% sodium chloride solution prepared to be pyrogen-free. Details of the preparation were described. The hypothesis was explored that the temperature response of rabbits after intravenous injection of the standard solution was independent of exogenous pyrogen. Reactions observed among the rabbits in our colony allowed a classification of these animals ranging from “consistently reliable” to “consistently unreliable.” Details of the experimental results and implications for pyrogen testing are discussed. The recommendation was made that all rabbit test animals be “screened” in sham and actual tests before being used for pyrogen testing.
Effect of Moisture on Ethylene Oxide Sterilization
Authors: Gilbert George L. , Gambill Vernon M. , Spiner David R. , Hoffman Robert K. , Phillips Charles R.
Published: December 2020

Bacterial cells dehydrated beyond a critical point no longer react uniformly to ethylene oxide sterilization. The percentage of cells resistant to the lethal effect of ethylene oxide after desiccation is often as small as 0.1 to 0.001%. However, 5% resistant cells were observed with one type of microorganism dried in broth. The presence of organic matter increases the percentage of cells that become resistant to ethylene oxide after dehydration. The phenomenon is produced by exposing cells to a vacuum or a chemically desiccated atmosphere. It is not a permanent change, because the resistant cells rapidly become susceptible if wetted with water. On the other hand, mere exposure to a high relative humidity (RH), i.e., 75 to 98%, after desiccation requires 6 and 4 days, respectively, to overcome this resistance. Moisture studies showed that there is less water in bacterial cells that have been desiccated and then equilibrated to successively high RH values up to 100% RH, than in cells that have not been desiccated, but allowed to dry naturally until equilibrated to the same RH values.
Blood-Free Medium for the Rapid Growth of
Pasteurella tularensis
Authors: Tresselt Hugh B. , Ward Martha K.
Published: December 2020

A medium composed of (in g/100 ml) Tryptose broth with thiamine (Difco), 2.6; cysteine-HCl, 0.12; glucose, 1; FeSO
4
, 7H
2
O, 0.005; KCl, 0.02; histidine, 0.1; tris(hydroxymethyl)aminomethane (tris) buffer, 0.3; and agar, 1; will support rapid growth of the fully virulent SCHU-S4 strain of
Pasteurella tularensis
. Although the test organism grew rapidly on medium from which KCl and tris buffer were omitted, these two components increased the stability of the medium upon storage at 4 C. It was necessary to (i) control carefully the relative concentration of the ferrous iron and cysteine-HCl, (ii) incubate the prepared medium overnight prior to use, and (iii) incubate the inoculated plates in an atmosphere of high relative humidity. Rapid growth of the organism was obtained also from very small inocula in the liquid form of the medium. Biochemical studies designed to elucidate the mechanisms involved in the enhancement of growth of
P. tularensis
in this relatively simple blood-free medium were initiated.
Antibiotics Against Plant Disease
Authors: Lindenfelser L. A. , Shotwell Odette L. , Bachler Marilyn J. , Shannon Gail M. , Pridham T. G.
Published: December 2020

In a survey of
Streptomyces
species, methods were designed and followed that would specifically select strains capable of producing heat-stable, nonpolyenic, antifungal antibiotics. Of 500 strains grown in shaken flasks, 240 of the culture liquors contained active factors as demonstrated by paper-disc assay against
Mucor ramannianus
. Culture filtrates and mycelial extracts of the active strains were examined by ultraviolet spectrophotometry; 166 were nonpolyenic as determined by absorption spectra. Heat-stability tests of the nonpolyenic antibiotics over a broad pH range revealed that 15 were stable under all test conditions, 70 moderately stable, and 81 unstable. Culture liquors containing stable, nonpolyenic antifungal agents were chromatographed with eight solvent systems in an attempt to identify the antibiotics. The producing cultures were studied by cross-antagonism tests to discover similarities with producers of known antibacterial antibiotics. Two of the antibiotics produced by promising strains were identified as cycloheximide and musarin. Six antibiotics, presumably new, were detected.
Rapid Method of Determining Coagulase Activity During Staphylococcal Bacteriophage Typing
Authors: Highsmith Anita K. , Shotts Emmett B.
Published: December 2020

The plate test, a modification of the slide test described by Cadness-Graves was developed for the rapid identification of coagulase-positive staphylococci in conjunction with bacteriophage typing. An evaluation of 1,145 cultures by three coagulase-determination methods, the slide, tube, and plate tests, indicates that the plate test is as accurate as the slide tests, and the plate test agrees 97.7% with the tube test.
Radiation Sterilization of Bacon for Military Feeding
Authors: Anellis A. , Grecz N. , Huber D. A. , Berkowitz D. , Schneider M. D. , Simon M.
Published: December 2020

Sliced, cured bacon, packed in cans and seeded with 6 × 10
5
spores per can of
Clostridium botulinum
strains 33A or 41B, or with 3 × 10
6
spores per can of strains 36A, 12885A, 9B, or 53B, was irradiated to various dose levels with γ radiation. Evidence provided by swelling, toxicity, and recoverable
C. botulinum
with 2,200 inoculated, irradiated cans demonstrated that: (i) 4.5 Mrad were more than adequate as a sterilization dose; (ii) the experimental minimal sterilizing dose was 2.0 Mrad, and the theoretical 12-log reduction dose was 2.65 or 2.87 Mrad depending on the method of calculation; (iii) some spoilage occurred at dose levels below 2.0 Mrad; (iv) all visible spoilage of irradiated bacon was due to strains 33A and 12885A only, whose
D
values were, respectively, 0.141 and 0.177 Mrad based on spoilage data, and 0.221 and 0.188 Mrad, respectively, when based on recovery data; (v) toxic cans did not always result in swelling, nor did swollen cans always produce toxic spoilage; and (vi) viable
C. botulinum
can exist for at least 8 months in storage at 30 C without producing visible or toxic spoilage at doses below 2.0 Mrad.
Garbage Composting for Mushroom Production
Authors: Block S. S.
Published: December 2020

Laboratory and pilot-plant composting of garbage mixtures of newspaper and vegetable waste has demonstrated that garbage can be converted to a medium that produces mushrooms (
Agaricus campestris
) in good yield. Sewage sludge was less satisfactory than newspaper, gumwood sawdust, or vegetable waste as a compost material for growing mushrooms. A sample of commercially produced compost was found to yield mushrooms in the same quantity as was produced in the laboratory experiments.
Fermentation Capacity as a Measure of Net Growth of Rumen Microorganisms
Authors: El-Shazly K. , Hungate R. E.
Published: December 2020

A simple technique for measuring the rate of fermentation of rumen microorganisms is described. It allows quick preparation and handling of the rumen sample immediately after collection. The average rate of fermentation of rumen samples collected from a lactating cow fed on alfalfa hay and concentrate in the ratio of 2:1 was very similar to the rate obtained by other methods. On the assumption that when substrate is in excess, the fermentation rate is proportional to the total microbial cells, the method was used to estimate the net growth of rumen microorganisms. The maximal fermentation rate of subsamples, taken at the beginning and after 1 hr of incubation of a sample, was measured. The results indicate a net average growth of 8% per hr, or 192% per day, in approximate agreement with rumen turnover time. The highest net growth does not necessarily coincide with the highest gas-production rate in the rumen, in part because the bicarbonate concentration in the rumen contents varies. In a cow fed on hay and concentrate, the net growth was lowest before feeding and immediately after feeding.
β-Propiolactone Decontamination of Simian Virus-40 as Determined by a Rapid Fluorescent-Antibody Assay
Authors: Levine S. I. , Goulet N. R. , Liu O. C.
Published: December 2020

β-Propiolactone vapor treatment of vaccine production facilities has been shown to be approximately 90% effective in the elimination of large quantities of Simian virus-40 (SV
40
). The use of a rapid fluorescent-antibody assay for the detection of SV
40
was also studied.
Improved Temperature-Gradient Incubator and the Maximal Growth Temperature and Heat Resistance of
Salmonella
Authors: Elliott R. Paul , Heiniger Patricia K.
Published: December 2020

An improved all-metal temperature-gradient incubator produces its gradient by means of a bar permanently installed in a near-vertical position with its lower end in a cool constant-temperature water bath and with thermostatically controlled heaters near its top. Bolts hold the incubator in contact with the temperature-gradient bar, and polyurethane foam insulates the entire assemblage during use. Maximal growth temperatures of 34 representative strains of
Salmonella
were found to be between 43.2 and 46.2 C. In an agar medium with an initial level of 10
6
cells per milliliter, no strain survived 50 C for 48 hr.
S. senftenberg
775W showed no greater heat resistance at or near 48 C than did other species or other
S. senftenberg
strains. However, it was considerably more resistant than other strains at 55 C.
Limitations of Fibrinogen-Polymyxin Medium in Detecting Coagulase-Positive Staphylococci in Raw Milk
Authors: Mcdivitt Maxine E. , Jerome Norge W.
Published: December 2020

A fibrinogen-polymyxin medium and Staphylococcus Medium 110 were used in the isolation of coagulase-positive staphylococci in raw milk. Results indicated that both media allow the growth of some rods and of many coagulase-negative cocci. A significantly greater number of coagulase-positive staphylococci were identified by the tube test than were revealed by halo formation on fibrinogen-polymyxin medium.
Characterization of Staphylococci Isolated from Raw Milk
Authors: Zemelman Raúl , Longeri Luis
Published: December 2020

To evaluate the pathogenicity of staphylococci from bovine raw milk, the general characteristics of 775 strains isolated from 798 samples of milk were studied. The coagulase test was performed by use of rabbit plasma. Chromogenesis, mannitol fermentation, and gelatin liquefaction were investigated on Chapman's Medium 110, after 48 hr of incubation. Production of β-hemolysin, which has been considered indicative of pathogenic staphylococci of animal origin, was determined by streaking different strains on sheep blood-agar plates in the presence of a strain of Lancefield group B streptococci. Plates were incubated at 37 C for 24 hr, and strong hemolysis was produced in the zone of interaction of β-hemolysin and some substance liberated by streptococcus (CAMP test). Of 404 strains found to be coagulase-positive, 95.8% exhibited a deep-orange pigment, 76.5% produced β-hemolysin, 91.8% fermented mannitol, and 75% liquefield gelatin. Of 371 strains which gave a negative coagulase test, about 16% fermented mannitol and liquefied gelatin; none of these strains produced β-hemolysin. When results are grouped according to pigmentation and coagulase production, β-hemolysin seems to be developed by pathogenic strains of
Staphylococcus aureus
only. If suitability of these tests for investigation of pathogenicity is compared, production of β-hemolysin appears to be the most useful one, since no “false positive” results were found. The use of the CAMP test as a simple and rapid technique to determine production of β-hemolysin by pathogenic strains of animal staphylococci during routine bacteriological work is suggested.
Isolation and Characterization of a New Antibiotic, ABBOTT 29119, from
Streptomyces erythreus
Authors: Hung P. P. , Marks C. L. , Tardrew P. L.
Published: December 2020

A new antibiotic was isolated from fermentations of
Streptomyces erythreus
designed for erythromycin A production. Isolation of this compound was accomplished by use of ion-exchange chromatography and countercurrent distribution. It crystallized from methyl isobutyl ketone in colorless acicular plates which melted at 127 to 130 C. The empirical formula was C
42
H
75
NO
14
with a molecular weight of 820. Electrometric titration in 66% dimethylformamide showed an apparent
p
Ka of 8.4. Nuclear magnetic resonance, infrared, and ultraviolet absorption indicated a close resemblance of the compound to known erythromycins, although its chromatographic behavior and solubility differed from those of the known erythromycins. Its antimicrobial spectrum was similar to erythromycin A, but the minimal inhibitory concentrations were much higher.
Chemical Composition of Cell-Wall Preparations from Strains of Various Form-Genera of Aerobic Actinomycetes
Authors: Becker B. , Lechevalier M. P. , Lechevalier H. A.
Published: December 2020

Cell-wall preparations were made from more than 140 strains of aerobic actinomycetes representing most of the form-genera that have been proposed. All cell-wall preparations contained as major constituents glucosamine, muramic acid, alanine, and glutamic acid. In addition, cell-wall preparations from various types of streptomycetes and strains of
Microëllobosporia
contained glycine and
ll
-α,ε-diaminopimelic acid; those from strains of most Actinoplanaceae and micromonosporae contained glycine and meso-α-ε-diaminopimelic acid; those from strains of
Thermoactinomyces, Microbispora, Dermatophilus
, and nocardiae of the
madurae-pelletieri
group contained meso-α,ε-diaminopimelic acid; and those from strains of
Thermomonospora, Micropolyspora
, and most nocardiae contained meso-α,ε-diaminopimelic acid, arabinose, and galactose. All the strains used were also studied morphologically.
Fermentative Production of Exocellular Glucans by Fleshy Fungi
Authors: Davis E. N. , Rhodes R. A. , Shulke H. Russell
Published: December 2020

Two specimens of higher fungi produced exocellular β-1, 3-glucans when their mycelial forms were cultivated under submerged aerobic conditions.
Plectania occidentalis
NRRL 3137 consumed up to 6% glucose or xylose with about 30% conversion to polymer in a medium composed of hydrolyzed soy protein, salts, and thiamine. A 5% inoculum was used in a 10-day shaken fermentation. After dilution of the culture liquors and partial disruption of mycelia with a blender, solids were removed by centrifugation, and the polymer was precipitated by the admixture of 2 volumes of ethyl alcohol. A second polymer was formed in 40 to 65% yield by fermentation with
Helotium
sp. NRRL 3129, which in the imperfect stage would be identified as
Monilia
sp. It consumed up to 4% glucose, fructose, mannose, or sucrose in 60 to 72 hr. A 2% inoculum in a medium composed of commercial defatted soy flakes, phosphate, and thiamine in tap water gave a satisfactory fermentation. This polymer was precipitated by the addition of 0.5 volume of ethyl alcohol. Both organisms have a broad
p
H optimum on the slightly acidic side and did best at about 25 C.
Micromethod (Spot-Plate) Determination of In Vitro Antibiotic Susceptibility
Authors: Beargie R. A. , Bracken E. C. , Riley H. D.
Published: December 2020

The spot-plate method for determining in vitro antibiotic susceptibility is a modified version of the standard tube dilution technique, with the same principle of twofold dilution. Results of the spot-plate method are compared with those of the standard tube dilution technique. It is proposed that the spot-plate method is an equally accurate, but more rapid and economical, technique for determining in vitro antibiotic susceptibility.
Agar-Gel Precipitin-Inhibition Technique for C-Reactive Protein Determinations
Authors: Ray John G. , Shay Donald E.
Published: December 2020

An application of the agargel precipitin-inhibition technique of Ray and Kadull detects the C-reactive protein present in the acute-phase human sera. The sensitivity of this procedure is compared with the capillary tube-precipitin method of Selman and Halpern.
Effect of Phenolic Acids and Esters on Respiration and Reproduction of Bacteria in Urine
Authors: Keith Elizabeth S. , Powers John J.
Published: December 2020

Vanillic, syringic, gallic, and protocatechuic acids, methyl-
p
-hydroxybenzoate, and propyl-
p
-hydroxybenzoate generally inhibited respiration in vitro of
Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa
, and
Aerobacter aerogenes
in human urine. In the absence of any other available carbon source, certain of the phenolic compounds were utilized. Reproduction was generally suppressed in urine buffered to
p
H 7, 5.6, 4.5, and 4.0. The phenolic compounds were used in the range of 0.11 to 0.99 μmole/ml.
Alpha Sarcin, a New Antitumor Agent
Authors: Olson B. H. , Goerner Gordon L.
Published: December 2020

Isolation and purification procedures are given for the new antitumor agent, alpha sarcin. These procedures include the use of column ion exchange with a carboxylic resin (Amberlite IRC50), dialysis, decolorization with activated charcoal, gradient salt chromatography, salt removal, and drying from the frozen state. The final product has an activity of 800 sarcoma 180 mouse dilution units per mg. The amino acid composition of the purified material is reported. All of the usual amino acids found in proteins were present except methionine. In addition to the usual amino acids, an unknown amino acid was present in the acid hydrolysate. The latter was isolated, and was found to yield phenylalanine and kynurenine. This compound, which has been named “sarcinine,” is extremely stable in 6
n
hydrochloric acid in the absence of air, and is unstable in alkali. Sarcinine has also been found in two other antitumor peptides produced by aspergilli, and so may relate significantly to the antitumor properties of these peptides.
Alpha Sarcin, a New Antitumor Agent
Authors: Olson B. H. , Jennings J. C. , Roga V. , Junek A. J. , Schuurmans D. M.
Published: December 2020

Aspergillus giganteus
MDH 18894 was found to produce alpha sarcin, a new antitumor agent inhibitory to a number of different animal tumors. This culture produced culture filtrates that inhibited mouse sarcoma 180 at dilutions up to 1:32. Optimal fermentation conditions were established for shake flasks and 30-liter and 100-gal (378.5-liter) fermentors. Results from a variety of media were reported; however, the medium which yielded the most reproducible filtrates consisted of 2% corn starch, 1.5% beef extract (Difco), 2% peptone (Difco), and 0.5% sodium chloride. Purified preparations of 800 sarcoma 180 dilution units per mg were inactive against bacteria, yeasts, molds, actinomycetes, and protozoa, but were cytotoxic to several strains of mammalian cells. Alpha sarcin inhibited sarcoma 180 in mice at a dose of 62.5 μg per kg per day. A variety of other animal tumors were also inhibited by this compound.
Action of Lipases of
Staphylococcus aureus
on Milk Fat
Authors: Vadehra D. V. , Harmon L. G.
Published: December 2020

The activity of the lipase(s) of two strains of coagulase-positive
Staphylococcus aureus
was determined in milk fat incubated at 15, 22, and 30 C for 8 days. Total fat hydrolysis was measured by acid degree values (ADV). Neutral lipids were separated into component groups on a Florisil column. Free fatty acids were determined by temperature-programmed gas-liquid chromatography. The ADV were 25 to 50% greater at 22 than at 15 C and 4 to 7 times greater at 30 than at 22 C. The lipases liberated as much as 0.48 g of fatty acids per gram of fat during 8 days at 30 C. The enzyme showed a predilection for the palmitic acid-glycerol bond. Addition of fatty acids C
14
to C
18
inclusive to inoculated sterile skim milk caused inhibition of
S. aureus
as follows: (i) complete at 0.05 and 0.10% concentration of C
10
and (ii) partial at 0.05 and complete at 0.10% concentration of C
8
. The samples showing inhibition were negative for peptonization, coagulase, and change in
p
H. Addition of oleic and stearic acid to sterile skim milk inoculated with
S. aureus
resulted in an increase in nonprotein nitrogen, and the C
4
to C
12
acids caused a decrease in protease activity.
Effect of Naturally Occurring Xanthines on Bacteria
Authors: Raj C. V. Sundar , Dhala Salim
Published: December 2020

The effect of xanthines on various microorganisms was studied. The antibacterial effect was not high; most of the test organisms could easily withstand a concentration of 2,500 μg/ml. Caffeine was more antibacterial than theophylline, and the latter more than theobromine. Caffeine citrate exhibited greater inhibitory effect than did pure caffeine. The effect was both bacteriostatic and bactericidal against susceptible organisms. The susceptibility of organisms to xanthines differed greatly even in related species. The morphology of
Aerobacter aerogenes
and
A. cloacae
was affected under the influence of caffeine; filamentation of cells followed sublethal doses. Potentiation was seen with antibiotics and caffeine; resistant strains were killed with a lower dose of drug in the presence of caffeine. This potentiating effect was pronounced with the tetracyclines; with streptomycin, the effect was the contrary.
Effect of Carob Pod Extract on Cellulolysis, Proteolysis, Deamination, and Protein Biosynthesis in an Artificial Rumen
Authors: Tagari H. , Henis Y. , Tamir Musha , Volcani R.
Published: December 2020

Carob pod extract and its tannin and sugar fractions were compared with gallotannic acid and sucrose for their effect on the cellulolytic, proteolytic, protein biosynthetic, and deaminative activities of rumen microorganisms. The inhibitory effects of carob pod extract upon the cellulolysis and deamination were correlated mainly with its sugar, rather than its tannin components. On the other hand, proteolytic activity and protein biosynthesis were more significantly affected by the tannin fraction. In contrast to the tannin fraction of carob pod extract, gallotannic acid inhibited cellulolytic activity. The harmful effect of a low concentration of tannins on protein biosynthesis could be prevented by the addition of carbohydrates to the reaction mixture. At high tannin concentration (40 μg/ml), however, the addition of carbohydrates did not prevent the inhibition.
Grinding Microorganisms with a Peristaltic Pump
Authors: Phillips James W. , Lamanna Carl , Mallette M. F.
Published: December 2020

The Randolph Co. model 610 peristaltic, ⅛-hp pump was effective for preparative purposes in disrupting baker's yeast and spores of
Bacillus globigii
when suspended with glass beads. Best results were obtained with use of a slurry just fluid enough to flow through tubing while stirred. Beads of 0.2 and 0.1 mm were used to best advantage for the yeast cells and spores, respectively. Yeast cells were disrupted completely within 15 min, and the spores in 10 to 30 min. Temperature and surface denaturation are readily controlled, and the system is easily modified for use with large quantities of microorganisms.
Production and Partial Purification of Antibiotic Materials Formed by
Physarum gyrosum
Authors: Considine Judith M. , Mallette M. F.
Published: December 2020

Pure cultures of
Physarum gyrosum
were grown on agar plates with autoclaved
Escherichia coli
suspensions as the growth medium. Portions of such agar, after growth of the slime mold, contained diffusible materials that inhibited the growth of
Bacillus subtilis, B. cereus, E. coli, Staphylococcus aureus
, and
Pseudomonas aeruginosa
. Paper chromatography of extracts of such cultures revealed at least three different active fractions. Preliminary fractionations increased the specific activity by one order of magnitude, probably in part by removal of inactive material and in part by separating active components. The fractionations also demonstrated the multiplicity of the antibiotic activity. Fractions variously obtained always retarded the growth of the bacterial species listed above.
Continuous Production of Flor Sherry from New York State Wines
Authors: Lüthi H. R. , Stoyla Brigitta , Moyer J. C.
Published: December 2020

Flor sherry-like wines were produced continuously from New York State wines from Delaware or cold-pressed Concord grapes whose pigment contents were reduced with activated carbon. The course of flor fermentation was followed by total aldehyde analysis. Optimal flor production was observed at 18 to 20 C. Two continuous methods of fermentation were used. A glass column packed with ceramic saddles densely covered with yeasts gave good results, but required more careful management than the second method of submerged fermentation in a laboratory fermentor, which gave a higher sherry output and higher aldehyde production. With the laboratory fermentor, it was possible to obtain a sherry output of 22 liters per 24 hr with an aldehyde content of 300 to 500 mg per liter. The flor sherry produced by these methods required subsequent aging and fortification to the desired alcohol content.
Chemistry of Antibiotics from
Micromonospora
Authors: Herzog H. L. , Meseck E. , Delorenzo S. , Murawski A. , Charney W. , Rosselet J. P.
Published: December 2020

The isolation of everninomicin D and everninomicin B, two closely related antibiotics produced by
Micromonospora carbonacea
, is described. The structures of everninomicin D and B are shown to parallel closely that of curamycin, a polysaccharidic antibiotic with a low molecular weight and a dichloroisoeverninic acid end group.
Effect of Temperature of Liquid Nitrogen on Radiation Resistance of Spores of
Clostridium botulinum
Authors: Grecz Nicholas , Snyder O. P. , Walker A. A. , Anellis A.
Published: December 2020

An apparatus consisting of a Dewar flask and a relay system controlling the flow of liquid nitrogen permitted the irradiation of samples in tin cans or Pyrex tubes at temperatures ranging from 0 ± 1.5 C to -194 ± 2 C. An inoculated pack comprising 320 cans of ground beef containing 5 × 10
4
spores of
Clostridium botulinum
33A per can (10 cans per radiation dose) was irradiated with Co
60
at 0 and -196 C. Incubation was carried out at 30 C for 6 months. Approximately 0.9 Mrad more radiation was required to inactivate the spores at -196 C than at 0 C. Cans irradiated at -196 C showed partial spoilage at 3.6 Mrad and no spoilage at 3.9 Mrad; the corresponding spoilage-no spoilage doses at 0 C were 2.7 and 3.0, respectively. The majority of positive cans swelled in 2 to 14 days; occasional swelling occurred as late as 20 days. At progressively higher doses, swelling was delayed proportionally to the radiation dose received. The remaining nonswollen cans had no toxin after 6 months of storage, although occasional cans contained very low numbers of viable spores comprising on the average 0.1% of the original spore inoculum. The
D
10
values in phosphate buffer were 0.290 Mrad for 0 C and 0.396 Mrad for -196 C; in ground beef, the corresponding
D
10
values were 0.463 Mrad and 0.680 Mrad, respectively. These
D
10
values indicate that the lethal effect of γ rays decreased at -196 C as compared with 0 C by 13.5% in phosphate buffer, and by 47% in ground beef.
Bitter Peptide Isolated from Milk Cultures of
Streptococcus cremoris
Authors: Gordon D. F. , Speck M. L.
Published: December 2020

Certain cultures of
Streptococcus cremoris
produced a bitter taste that occurred in the whey portion of milk cultures. Whey from a culture which produced bitterness was fractionated on Sephadex. The fraction in which the bitter taste was concentrated was chromatographed successively on paper with butanol-acetic acid-water (5:1:4), and then butanol-2-butanone-water (2:2:1). In each instance, the bitter component was in the most rapidly moving band that gave a positive ninhydrin test. The bitterness was observed to be caused by a peptide containing the following numbers of each amino acid: arginine, 1; glutamic acid, 2; glycine, 2; isoleucine, 2; leucine, 2; phenylalanine, 1; proline, 5; and valine, 4. N-terminal amino acids could be detected by coupling with 2,4-dinitrofluorobenzene or phenylisothiocyanate, or by hydrolysis with leucine aminopeptidase. When treated with carboxypeptidase, only leucine and valine appeared at the C-terminal end, and these were detected simultaneously.
Relative Stability of Pertussis Vaccine Preserved with Merthiolate, Benzethonium Chloride, or the Parabens
Authors: Gardner Roberta A. , Pittman Margaret
Published: December 2020

When stored at 4 C, or heated at 22 or 35 C followed by storage at 4 C, the potency of pertussis vaccines preserved with Merthiolate was more stable than the potency of vaccines preserved with benzethonium chloride or the parabens (methyl- and propyl-
p
-hydroxybenzoate). Without preservative, potency was more stable than in the presence of benzethonium chloride or the parabens, but less stable than when Merthiolate was present. The histamine-sensitizing factor of the vaccines likewise decreased with the loss of potency. The deleterious effect of benzethonium chloride and the absence of the stabilizing effect of Merthiolate were contributing factors, if not the sole cause, for the instability of pertussis vaccine in quadruple antigen vaccine (diphtheria and tetanus toxoids and pertussis and poliomyelitis vaccines).
Sensitivity of Mixed Populations of
Staphylococcus aureus
and
Escherichia coli
to Mercurials
Authors: Stutzenberger F. J. , Bennett E. O.
Published: December 2020

Staphylococcus aureus
was found to have a higher resistance to merbromin and mercuric chloride in the presence of
Escherichia coli
. The protective effect of the gram-negative organism on
S. aureus
was due to the production of extracellular glutathione and hydrogen sulfide and to an unequal distribution of the inhibitor between the two species.
S. aureus
did not significantly influence the resistance of
E. coli
to mercurials.
In Vivo Antiviral Activity of 1,3-Bis(2-Chloroethyl)-1-Nitrosourea
Authors: Sidwell Robert W. , Dixon Glen J. , Sellers Sara M. , Schabel Frank M.
Published: December 2020

A prolongation in the lives of Swiss mice inoculated intracerebrally with lymphocytic choriomeningitis virus (LCM) was observed after treatment with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). A variety of treatment schedules, including therapy once or twice daily up to 17 days and single treatments at various times after virus inoculation, were employed. Virus titers ranging to greater than 10
4
were detected in the blood and brains of surviving drug-treated animals. In three comparative studies in which different treatment schedules were used, BCNU was shown to exert a protective effect approximately equal to that of methotrexate in LCM virus-infected mice. Tests were also carried out to investigate the activity of BCNU in mice experimentally infected with eastern equine encephalomyelitis (EEE) virus, western equine encephalomyelitis virus, Semliki Forest (SF) virus, herpes simplex virus, influenza virus strain PR8, vaccinia virus strain WR, Rous sarcoma virus, Friend leukemia virus (FLV), and poliovirus. Slight increases in life span were observed in the treated EEE, SF, and influenza PR8 virus-infected animals. Significant reduction in splenomegaly in FLV-infected animals treated with BCNU was demonstrated. The possible mechanisms of LCM virus inhibition by BCNU, on the basis of these and other studies, were postulated to be either specific antiviral activity or inhibition of “lethal” immune response to the LCM virus. Each of these postulates is discussed.
Use of Antibiotics in the Preparation of Canine Kidney Tissue Culture Vaccines to Eliminate Leptospiral Infection Hazards
Authors: Ellison D. , Rigg J. , Mcconnell S. J. , Alexander A. D. , Yager R. H.
Published: December 2020

The potential leptospiral infection hazard in the use of vaccines prepared from canine kidney monolayer cultures was studied. Cell cultures were prepared from kidneys of dogs experimentally infected with
Leptospira
serotype
canicola.
Viable leptospires were found in kidney cell suspensions at the time of seeding, surviving trypsinization either at room temperature for approximately 2 hr or overnight at 4 C, even in the presence of antibiotics. In tissue cultures maintained without antibiotics, leptospires were cultured up to the time of involution of cells at 25 to 34 days of incubation. Cytopathogenic effects of leptospires on cultured kidney cells were not noted; neither was growth of leptospires remarkable. Generally, the leptospire culture titer decreased to 10
-4
or 10
-5
at the 4th hr or 1st day of incubation to 10
-1
or negative by the 30th or 34th day of incubation. The addition of either a combination of penicillin (100 units per ml) plus streptomycin (100 μg/ml) or polymyxin B (50 units per ml) plus dihydrostreptomycin (100 μg/ml) to seeding cell suspensions resulted in the elimination of viable leptospires by the 4th hr of incubation. From cell cultures treated with neomycin (100 μg/ml) or chloramphenicol (100 μg/ml), leptospires were recovered, respectively, after 24 and 48 hr, but not thereafter. It was apparent that antibiotics, particularly the combination of polymyxin B and dihydrostreptomycin, could be effectively used to eliminate leptospires in tissue culture. Other antibiotics with known antileptospiral activities probably would be effective also. If antibiotics are not used in canine kidney tissue culture employed for viral vaccine preparations, rigid testing for the presence of leptospires in donor dogs and tissue-culture vaccine is indicated.
Current Status of Immunofluorescence Techniques for Rapid Detection of Shigellae in Fecal Specimens
Authors: Thomason Berenice M. , Cowart Glenda S. , Cherry William B.
Published: December 2020

Polyvalent
Shigella
conjugates were prepared for
Shigella
groups A, B, C, and D. After preliminary testing with pure cultures of both homologous and heterologous organisms, these reagents were used in three evaluation studies. Fecal specimens from patients hospitalized with diarrhea, from children involved in an institutional outbreak of dysentery due to
S. sonnei
, and from patients with diarrhea in Arizona were screened by fluorescent-antibody (FA) tests and were cultured. Specimens were examined at various periods of time after collection and after incubation in broth and saline. Results showed that shigellae were detected most frequently when specimens were cultured immediately after collection. FA tests revealed more positive results when the specimens were incubated in either saline or broth than when they were examined immediately after collection. The
S. sonnei
conjugate gave the most reliable results of any of the
Shigella
FA reagents used in these investigations. It proved to be both sensitive and specific.
Amino Acid Isomerization in the Production of
l
-Phenylalanine from
d
-Phenylalanine by Bacteria
Authors: Chibata Ichiro , Tosa Tetsuya , Sano Ryujiro
Published: December 2020

To establish an advantageous method for the production of
l
-amino acids, microbial isomerization of
d
- and
dl
-amino acids to
l
-amino acids was studied. Screening experiments on a number of microorganisms showed that cell suspensions of
Pseudomonas fluorescens
and
P. miyamizu
were capable of isomerizing
d
- and
dl
-phenylalanines to
l
-phenylalanine. Various conditions suitable for isomerization by these organisms were investigated. Cells grown in a medium containing
d
-phenylalanine showed highest isomerization activity, and almost completely converted
d
- or
dl
-phenylalanine into
l
-phenylalanine within 24 to 48 hr of incubation. Enzymatic studies on this isomerizing system suggested that the isomerization of
d
- or
dl
-phenylalanine is not catalyzed by a single enzyme, “amino acid isomerase,” but the conversion proceeds by a two step system as follows:
d
-pheylalanine is oxidized to phenylpyruvic acid by
d
-amino acid oxidase, and the acid is converted to
l
-phenylalanine by transamination or reductive amination.
Increase in Sensitivity for the Assay of Neomycin in Milk
Authors: Siddique I. H. , Loken K. I. , Hoyt H. H.
Published: December 2020

A study was conducted to design a more sensitive and flexible technique for the assay of neomycin in milk. Sterile Antibiotic Assay medium (Difco; 15 ml) was poured into glass petri dishes with aluminum tops equipped with absorbent discs. Seed agar (4 ml; containing 1% sodium chloride) inoculated with standardized amounts of the test organism (
Staphylococcus epidermidis
ATCC 12228) was laid over the hardened base agar, and stainless-steel cylinders were placed equal distances apart in the agar. The plates were refrigerated for 30 min and the cups were removed in an atmosphere of minimal contamination. The resultant holes were sealed with melted agar. After preparation, the holes were used for assay procedures. Samples to be assayed were pipetted into the holes and the plates were refrigerated for 90 min at 4 C. Plates were incubated for 18 to 20 hr at 32 C. The zones of inhibition were recorded and compared with a standard curve. The approximate sensitivity of this method was 0.05 μg/ml.
Amino Acid Composition of Certain Bacterial Cell-Wall Proteins
Authors: Howe Jean M. , Featherston W. R. , Stadelman W. J. , Banwart G. J.
Published: December 2020

Analyses were made to determine the amino acid composition of the cell-wall proteins of
Salmonella pullorum, S. senftenberg
775W,
S. derby
, and
Escherichia coli
. These proteins consist of the usual 18 amino acids found in most proteins with diaminopimelic acid in addition. Quantitative determination of these amino acids showed that their amounts were similar.
Specificity of Immunofluorescent Staining for Study of
Aspergillus flavus
in Soil
Authors: Schmidt E. L. , Bankole R. O.
Published: December 2020

Fluorescein-labeled antiserum prepared with
Aspergillus flavus
strain CS was tested for specificity by staining fungi grown in soil in the vicinity of buried slides. All 14 strains of
A. flavus
fluoresced as intensely or nearly as intensely as the antigen control. Among 21 isolates of species of
Aspergillus
other than
A. flavus
, 17 reacted with moderate to low fluorescence at intensities readily distinguishable from that of
A. flavus
. The fluorescence of the remaining four cultures, and particularly
A. sydowi
, was indistinguishable from that of
A. flavus
. Fungi other than aspergilli were generally nonreactive. Interfering cross-reactions were encountered for one strain of
Spicaria
and one strain of
Stemphylium
; three isolates could not be evaluated because of interfering autofluorescence. An additional 22 isolates were either wholly negative or had a low order of fluorescence. Agglutination tests between each of the fungi and
A. flavus
CS serum revealed close agreement between agglutination titer and fluorescent-staining reaction. Unknown fungi freshly isolated from soil were checked for reaction to the
A. flavus
labeled antiserum; only one isolate gave a pronounced staining reaction, and that one proved to be a strain of
A. flavus
. In a simplified ecological model, the fluorescent-antibody technique was used to follow the development of
A. flavus
in mixed culture in soil with five other soil fungi.
Primary Alcohol Sulfatase in a
Pseudomonas
Species
Authors: Payne W. J. , Williams Joy P. , Mayberry W. R.
Published: December 2020

An ammonium sulfate-precipitated fraction from cell-free extracts of
Pseudomonas
C12B grown on a medium containing sodium dodecyl sulfate (SDS) contained alkyl sulfatase increased fourfold in specific activity over the crude. Optimal
p
H (7.5) and temperature (70 C) for sulfate release were determined with SDS labeled with radioactive sulfur (SDS
35
) as test substrate. Phosphate, arsenate, and certain heavy metal ions inhibited desulfation, whereas Mg
++
and Mn
++
stimulated activity of preparations which had been dialyzed against ethylenediaminetetraacetic acid. Dodecanol was recovered in semiquantitative yield from reaction mixtures containing enzyme and SDS
35
. Aryl sulfates, secondary alcohol sulfates, and a phenoxyethyl sulfate failed to serve as substrate for this enzyme.
Production of Xanthosine-5′-Monophosphate and Inosine-5′-Monophosphate by Auxotrophic Mutants of a Coryneform Bacterium
Authors: Demain Arnold L. , Jackson Marion , Vitali Ronald A. , Hendlin David , Jacob Theodore A.
Published: December 2020

Although most microorganisms with genetic blocks in the purine nucleotide sequence excrete breakdown products, a coryneform bacterium was found to accumulate intact 5′-nucleotides in the extracellular medium. Adenineless mutants accumulated 0.4 to 0.6 g of inosine-5′-monophosphate per liter of broth. The yield of this nucleotide was increased to 0.8 to 0.9 g per liter when such mutants were mutated to xanthine dependence. Induction of a specific guanine requirement in adenineless auxotrophs resulted in cultures capable of producing high yields of xanthosine-5′-monophosphate (3 to 4 g per liter). Pure xanthosine-5′-monophosphate was isolated from broth by a procedure involving ion-exchange chromatography, charcoal adsorption, and barium precipitation.
Antibiotic Sensitivities of Organisms Isolated from Mastitic and Nonmastitic Mammary Secretions
Authors: Krabbenhoft K. L. , Adams A. Paul , Schipper I. A.
Published: December 2020

Antibiotic sensitivity tests to determine the minimal inhibitory concentrations (MIC) and the minimal lethal concentrations (MLC) for six antibiotics were conducted against mastitic isolates of staphylococci in skim milk and broth. The MIC and the MLC for all the antibiotics except benzylpenicillin were considerably higher in skim milk than in broth. Benzylpenicillin was the most effective antibiotic tested in either medium, and dihydrostreptomycin was the least effective against the organisms tested.
Effects of Oxygen on Aerosolized
Serratia marcescens
Authors: Hess George E.
Published: December 2020

Suspensions of
Serratia marcescens
(ATCC strain 14041) in water were aerosolized in a rotating drum in the presence of various concentrations of oxygen. The colony-forming ability of aerosolized organisms was rapidly destroyed by contact with 0.25% or more oxygen at 40% relative humidity (RH) and 25 C, but was almost unimpaired for at least 5 hr in nitrogen containing not more than 10 ppm of oxygen. Completely hydrated organisms were insensitive to oxygen at pressures up to 100 psi for 4 hr. No loss in viability occurred in aerosols of washed cells in air at 97% RH. It is proposed that dehydration of the aerosolized cell results in sensitization to lethal effects of oxygen, but is not the primary cause of death. Mn
++
, Co
++
, glycerol, and thiourea enhanced the biological stability of aerosols in air. Numerous similarities between the effects of oxygen in this system and in systems using freeze-dried or irradiated organisms or cell-free enzymes support the hypothesis that closely related mechanisms are involved.
Cultural, Biochemical, and Immunological Properties of
Mima, Herellea
, and
Flavobacterium
Species
Authors: Nelson John D. , Shelton Sharon
Published: December 2020

From study of cultural and biochemical characteristics of 40 strains of
Herellea, Mima
, or
Flavobacterium
species, a proposed schema for identification was developed. The reactions observed by agglutination, gel diffusion, and immunofluorescence suggest antigenic heterogeneity of this group of organisms.
Application of Replica Plating and Computer Analysis for Rapid Identification of Bacteria in Some Foods
Authors: Corlett D. A. , Lee J. S. , Sinnhuber R. O.
Published: December 2020

A method was devised and tested for a quantitative identification of microbial flora in foods. The colonies developing on the initial isolation plates were picked with sterile toothpicks and inoculated on a master plate in prearranged spacing and order. The growth on the master plates was then replicated on a series of solid-agar plates containing differential or selective agents. The characteristic growth and physiological responses of microbial isolates to penicillin, tylosin, vancomycin, streptomycin, chloramphenicol, neomycin, colistin, and to S S Agar, Staphylococcus Medium No. 110, and Potato Dextrose Agar were recorded, together with Gram reaction and cell morphology. This information was then fed into an IBM 1410 digital computer which grouped and analyzed each isolate into 10 microbial genera, or groups, according to the identification key. The identification scheme was established by use of reference culture studies and from the literature. This system was used to analyze the microbial flora in dover sole (
Microstomus pacificus
) and ground beef. The method described in this article enables one to examine large numbers of microbial isolates with simplicity.
Application of Replica Plating and Computer Analysis for Rapid Identification of Bacteria in Some Foods
Authors: Corlett D. A. , Lee J. S. , Sinnhuber R. O.
Published: December 2020

This investigation was carried out to determine the nature of the microbial flora shifts in dover sole as a result of irradiation and storage at 6 C. The relationship was determined between the microorganisms which initially survive irradiation and those making up the final spoilage flora. A total of 2,723 isolates were examined by use of the replica-plating and computer analysis method. The spoilage of the unirradiated control samples during storage at 6 C was almost entirely due to the growth of
Pseudomonas
. This group, which occupied 25% of the fresh flora, grew to nearly 100% in 2 days of storage. In contrast, irradiation doses of 0.1, 0.2, 0.3, and 0.4 Mrad favored the growth of
Achromobacter
and yeasts. The
Micrococcus
, which survived radiation, did not grow at 6 C. At 0.5 Mrad, spoilage of fish samples was due entirely to the growth of yeasts.
Filtration Method for Bacteriophage Detection
Authors: Loehr Raymond C. , Schwegler Diann T.
Published: December 2020

A filtration method has been developed which can be used to detect and enumerate phage in low concentrations directly from solution without the need for prior concentration. In this method, a known volume of the phage solution is mixed with a suitable host solution. Samples are filtered through membrane filters; the filter is removed and incubated, and after 24 hr the resultant plaques are counted and the titer is calculated.
Escherichia coli
B and the coliphage T2 were used in these studies. Host cultures less than 12 hr old produced the best results. Approximately 10
10
host organisms must be present in the sample taken for filtration. To avoid phage reproduction, all steps prior to filtration must be done in less than 45 min. The method was compared with the soft-agar technique and was shown to be less precise but able to measure phage in lower concentrations.