bluuebunny/crossref_metadata_2025 huggingface dataset:
Method for Quantitating Formaldehyde Gas in Air
Authors: Braymen D. T. , Songer J. R.
Published: December 2020

A quick, simple method for collecting and assaying the disinfecting concentrations of formaldehyde vapor is described.
Partial Substitution of Serum in Hematopoietic Cell Line Media by Synthetic Polymers
Authors: Mizrahi A. , Moore G. E.
Published: December 2020

Several synthetic polymers (hydroxyethyl starch, sodium carboxymethyl cellulose, polyvinylpyrrolidone) markedly improved the growth of three human lymphocyte cell lines [Roswell Park Memorial Institute (RPMI) 1348, 1788, and 8098]. Growth was stimulated when each of these polymers was added to RPMI 1640 medium supplemented with only 2% fetal bovine serum. Dextran T-40, T-70, and T-110 varied in their effect on the growth of these cell lines. Dextran T-250 and Haemaccel did not improve cell yields when partially substituted for the serum. The successful partial substitution of polymers for serum was specific for individual cell lines.
Hydrogen Sulfide Production by Bacteria and Sulfmyoglobin Formation in Prepacked Chilled Beef
Authors: Nicol D. J. , Shaw M. K. , Ledward D. A.
Published: December 2020

Meat stored at 1 to 2 C under low oxygen tensions, either in gas-impermeable packs or in controlled atmospheres, occasionally exhibited an undesirable green exudate. The green pigment was identified spectrophotometrically as sulfmyoglobin. The conversion of myoglobin to sulfmyoglobin resulted from the production of H
2
S by bacteria tentatively identified as
Pseudomonas mephitica
. This organism produced H
2
S only when the oxygen tension was about 1% and the
p
H of the meat was 6.0 and above.
Microbial Biomass on Particulate Organic Matter in Seawater of the Euphotic Zone
Authors: Seki Humitake
Published: December 2020

Microbial biomass on suspended organic matter in seawater of the euphotic zone of Saanich Inlet was investigated. The viable microorganisms were measured by the glucose-uptake method. Microbial carbon on particulate organic matter in seawater was determined to be, on the average, 9.9 μg of C/liter, and there was a regression relationship as
y
= 0.0062
x
− 1.79 with an unbiased variance
V
yx
1/2
= 0.38, where
x
= particulate organic carbon in seawater (micrograms of C/liter) and
y
= logarithm of microbial carbon (micrograms of C/liter).
Plaque Assay for Q Fever and Scrub Typhus Rickettsiae
Authors: McDade Joseph E. , Gerone Peter J.
Published: December 2020

The plaque assay procedure developed for spotted fever and typhus group rickettsiae is also appropriate for scrub typhus and Q fever rickettsiae. The plaque titers of suspensions of
Rickettsia tsutsugamushi
and
Coxiella burnetii
compared favorably with end points obtained by titrations in mice.
Control of Molds During the Enumeration and Isolation of Yeasts from Soil and Plant Material
Authors: Etchells J. L. , Costilow R. N. , Bell T. A. , Demain A. L.
Published: December 2020

Images

Fig. 1
Medium for Differential Count of the Anaerobic Flora in Human Feces
Authors: van der Wiel-Korstanje J. A. A. , Winkler K. C.
Published: December 2020

On reinforced clostridial agar with blood and 0.03% China blue, organisms of the bacteroides group grow with blue translucent colonies, whereas bifidobacteria grow with opaque brown colonies. This permits the differential counting of the predominant anaerobic organisms in human feces on one medium.
Zearalenone Production by
Fusarium
Species
Authors: Caldwell Rodney W. , Tuite John , Stob Martin , Baldwin Robert
Published: December 2020

One-hundred-and-thirteen isolates of
Fusarium
were tested for their ability to produce zearalenone on autoclaved corn. They belonged to the following species (number of producers per number tested):
F. epispheria
, (0/1);
F. moniliforme
, (0/8);
Gibberella fujikuroi
, (0/3);
F. nivale
, (0/7);
F. oxysporum
, (0/15);
F. roseum
, (31/51);
F. solani
, (0/9);
F. tricinctum
(3/19). The isolates of individual species produced the following amounts of zearalenone per gram of corn: 3 isolates of
F. roseum
(0.6 to 119 μg), 3 of
F. roseum
“Culmorum” (1 to 210 μg), 3 of
F. roseum
“Equiseti” (0.6 to 2.0 μg),
F. roseum
“Gibbosum” (115 to 175 μg), 21 of
F. roseum
“Graminearum” (0.2 to 230 μg), and 3 of
F. tricinctum
(0.2 to 6.0 μg). All isolates of
F. roseum
“Graminearum” which formed the perithecial stage of
G. zeae
(
G. roseum
) produced zearalenone. Production occurred by the wild but not the appressed cultural type. Zearalenone production by
F. tricinctum
was confirmed by a mouse bioassay.
Survival of Virus in Chilled, Frozen, and Processed Oysters
Authors: DiGirolamo R. , Liston J. , Matches J. R.
Published: December 2020

Samples of whole and shucked Pacific and Olympia oysters, contaminated with 10
4
-plaque-forming units (PFU) of poliovirus Lsc-2ab per ml, were held refrigerated at two temperatures, 5 and - 17.5 C. To study the survival of virus in the oysters under these conditions, samples were assayed for virus content at weekly intervals for as long as 12 weeks. Results indicated that poliovirus would survive in refrigerated oysters for a period varying from 30 to 90 days, depending upon temperature. The survival rate varied from 10 to 13%. To study the extent of the hazard presented by oysters contaminated with virus, samples of whole and shucked Pacific oysters contaminated with 10
4
PFU of poliovirus Lsc-2ab per ml were heat processed in four ways: by stewing, frying, baking, and steaming. Results indicated that virus in oysters withstood these methods of processing. The survival rate varied from 7 to 10% and appeared dependent upon the processing method used. Heat penetration studies showed that the internal temperature in the oyster was not sufficient to inactivate all of the virus present. These results suggest that not only fresh but also refrigerated and cooked oysters can serve as vectors for the dissemination of virus disease if the shellfish are harvested from a polluted area.
Recovery of Rauscher Leukemia Virus from Large Volumes of Seeded Cow's Milk and from Infected Murine Spleens
Authors: Larkin Edward P. , Dutcher Ray M.
Published: December 2020

Rauscher murine leukemia virus was used as an indicator agent to develop a methodology for the extraction and concentration of a theoretical leukemia virus from bovine milk and tissues. The indicator virus was seeded into cow's milk or was recovered from infected murine spleens. The tissue homogenates and the defatted milk were processed in a B-XVI rotor of a Spinco L-4 ultracentrifuge at a flow rate of 3 liters/hr. The efficiency of Rauscher virus recovery was greatest when the rotor was used without a gradient. A loss of between 0.6 and 0.7 log of total infectious virus, as determined by the spleen assay method, resulted when the seeded milk and murine spleens were processed. The procedures developed are presently being used in transmission experiments in an attempt to induce leukemia in the bovine.
Evaluation of Methods for Reestablishment of L-Cell Suspension Cultures Directly from Liquid Nitrogen Stored Stocks
Authors: Weirether Francis J. , Walker Jerry S. , Carter Richard C. , Lincoln Ralph E.
Published: December 2020

Methods were developed and evaluated for the preservation of tissue cells grown in suspension culture and the reestablishment of suspension cultures directly from inoculum stored at −175 C. The factors investigated were processing
p
H, temperature of processing, freezing medium, and method of inoculation of the starter suspension cultures from the frozen stock (−175 C). Three parameters, cell viability, cell size, and growth potential in suspension culture after freezing, were used to evaluate the various factors. The results indicate that cells processed at 4 C, frozen at 1 C per min to −50 C in a medium containing 5% dimethyl sulfoxide plus 10% bovine serum at concentrations of 2 × 10
7
to 4 × 10
7
cells/ml, and stored at −175 C will reestablish suspension cultures directly from frozen seed. A 1-ml amount of frozen stock inoculated into 99 ml of medium routinely produced 2 × 10
6
to 3 × 10
6
viable cells/ml (2 × 10
8
to 3 × 10
8
total cells) in suspension culture in 4 to 5 days. Inoculum preserved by this procedure grew equally well in either serum-free or serum-containing growth medium.
Relative Numbers of Certain Microbial Groups Present in Compost Used for Mushroom (
Agaricus bisporus
) Propagation
Authors: Fordyce C.
Published: December 2020

The relative numbers of microorganisms associated with compost during mushroom production were studied by the dilution plate method. Thermophilic actinomycetes and fungi were isolated with a very high frequency early in the growing season. Although numbers of thermophilic bacteria diminished slowly during the season, the thermophilic fungi and actinomycetes diminished rapidly with the latter disappearing after 6 weeks. Mesophilic fungi other than
Agaricus
or
Trichoderma
remained relatively stable throughout the growing period.
Agaricus
could be isolated between the first and third break.
Trichoderma
became dominant after the fourth break. The mesophilic bacterial counts diminished during the most productive portion of the mushroom cropping season and then increased to much higher numbers toward the end of the season.
Cometabolism of
m
-Chlorobenzoate by an
Arthrobacter
Authors: Horvath R. S. , Alexander M.
Published: December 2020

Twenty isolates representing nine bacterial genera were obtained from enrichment cultures and were shown to cometabolize one or more of 22 substituted benzoates. One of the isolates, an
Arthrobacter
sp., cometabolized
m
-chlorobenzoate to a product identified as 4-chlorocatechol by thin-layer chromatography and ultraviolet and infrared spectroscopy. The data indicate that cometabolism by the arthrobacter results from the formation of products by its benzoate-oxiding enzyme system that are not acted upon by the catechol-metabolizing enzymes of the bacterium.
Methods Used to Monitor the Microbial Load of Returned Lunar Material
Authors: Taylor Gerald R. , Ferguson J. Kelton , Truby Charles P.
Published: December 2020

Methods employed to prepare lunar soil samples and procedures used to detect viable microorganisms are described.
Development of a Camel Kidney Cell Strain and Its Use in Virology
Authors: Mirchamsy H. , Bahrami B. , Amighi M. , Shafyi A.
Published: December 2020

A strain of camel kidney cells was developed and carried in serial passages. The subcultures were slow-growing in the early passages and were composed of heterogeneous cell population. By the 35th passage, the growth rate increased, and more homogeneous cells, mostly of the epithelioid type, were seen. The cell strain was highly susceptible to West Nile, Sindbis, vesicular stomatitis, adeno, and vaccinia viruses, and also was susceptible to herpes simplex, rinderpest, measles, and canine distemper viruses.
Rapid Assay for Bactericidal Antibodies
Authors: Hansen Gary D. , Armstrong Alan S.
Published: December 2020

Microtiter plates were successfully substituted for tubes in the bactericidal test for opsonic antibodies. This method is efficient and should prove useful for screening large numbers of sera.
Seasonal Incidence of Bacterial Temperature Types in Louisiana Soil and Water
Authors: Larkin John M.
Published: December 2020

Psychrophilic bacteria were not detected in soil, mud, and water in the summer. In winter, they were present in water and mud and constituted a significant portion of the bacterial flora in lake water.
Assessment of Aerosol Mixtures of Different Viruses
Authors: Mayhew Charles J. , Hahon Nicholas
Published: December 2020

Aerosol mixtures of the psittacosis agent, yellow fever virus, and variola virus were assayed by selective immunofluorescence in conjunction with fluorescent cell counting. The aerosol behavior of each agent could be readily delineated at test conditions of 80 F (26.67 C) and three relative humidities (30, 50, or 80%). Of the three agents, variola virus exhibited the lowest biological decay. The biological decay rates of the airborne agents were not significantly affected by humidity changes.
Concentration of Rift Valley Fever and Chikungunya Viruses by Precipitation
Authors: Klein Frederick , Mahlandt Bill G. , Cockey Ralph R. , Lincoln Ralph E.
Published: December 2020

Simple and efficient methods for concentrating Rift Valley fever (RVF) virus and chikungunya (CHIK) virus are described. Ammonium sulfate, potassium sulfate, or alcohol was used as a precipitating agent and the precipitate was resuspended to volumes suitable for further processing and purification. The methods permitted concentration of live RVF virus and CHIK virus about 100-fold with negligible losses of virus. RVF virus retained a high level of infectivity with potassium aluminum sulfate and alcohol, but CHIK virus retained a higher infectivity level with ammonium sulfate than with potassium aluminum sulfate. The data indicate that serum plays an important role in the concentration of both viruses, at least when the sulfate methods are used.
Absence of 5-Hydroxy-4-Ketohexanoate and the α-Ketoglutarate Dehydrogenase Complex in Mutants of
Saccharomyces oviformis
Incapable of Growing on Ethanol
Authors: Hirabayashi Takashi , Harada Tokuya
Published: December 2020

The roles of the enzyme which forms 5-hydroxy-4-ketohexanoate (HKH) and of related enzymes in the metabolism of ethanol were studied in
Saccharomyces oviformis
WH92 and its mutants, which grew poorly or not at all on ethanol. The strains, which did not grow on ethanol, did not form HKH from α-ketoglutarate and acetaldehyde enzymatically and were also devoid of the α-ketoglutarate dehydrogenase complex. Acetaldehyde inhibited the activity of α-ketoglutarate dehydrogenase. These mutants did not grow on acetate since they had no acetyl-CoA synthetase activity. The relationship of the formation of HKH with the metabolism of ethanol is discussed.
Quantitative and Qualitative Microbiological Profiles of the Apollo 10 and 11 Spacecraft
Authors: Puleo John R. , Oxborrow Gordon S. , Fields Norman D. , Hall Herbert E.
Published: December 2020

Microbiological profiles were determined for surfaces of the command module, lunar module (ascent and descent stages), instrument unit, Saturn S-4B stage, and the spacecraft lunar module adapter of the Apollo 10 and 11 spacecraft. Average levels of contamination of the command module were 2.1 � 10
4
and 2.7 � 10
4
microorganisms per ft
2
for Apollo 10 and 11, respectively. With the exception of the exterior surfaces of the ascent stage of the lunar module and the interior surfaces of the command module, average levels of microbial contamination on all components of the Apollo 11 were found to be lower than those observed on Apollo 10. For each Apollo mission, approximately 2,000 colonies were picked from a variety of media and identified. The results showed that approximately 95% of all isolates were those considered indigenous to humans; the remaining were associated with soil and dust in the environment. However, the ratio of these two general groups varied depending on the degrees of personnel density and environmental control associated with each module.
New
Moraxella
Strain Isolated from Angular Conjunctivitis
Authors: van Bijsterveld O. P.
Published: December 2020

A new
Moraxella
strain was isolated from angular conjunctivitis. It is characterized by the ability to produce acid from several carbohydrates, by its ability to produce indole, and by a lack of catalase activity.
Isolation and Characterization of a Staphylococcal Lipase
Authors: Troller J. A. , Bozeman M. A.
Published: December 2020

A number of coagulase-negative staphylococci isolated from human skin were found to produce lipase. Lipolytic activity appeared in the growth medium during the stationary phase of growth but did not appear as a result of autolysis of the cells. Maximal lipase synthesis was obtained when the medium was adjusted to
p
H 7.5 before inoculation. The purified enzyme hydrolyzed tributyrin and tridecanoin most actively, and a relatively high rate of hydrolysis of triolein was also noted. The optimal activity of the purified lipase was at
p
H 7.5. The characteristics of the concentrated crude enzyme and purified lipase were compared.
Polymyxin-Coagulase-Deoxyribonuclease-Agar: a Selective Isolation Medium for
Staphylococcus aureus
Authors: Orth D. S. , Anderson A. W.
Published: December 2020

Fibrin halos developed around coagulase-positive
Staphylococcus aureus
colonies, and deoxyribonuclease production was detected by using a developing solution containing 1 mg of methyl green per ml.
Improved Bacteriophage-Bacteriocin Applicator
Authors: Farmer J. J.
Published: December 2020

Teflon spaghetti tubing was placed over the metal needles of the dispensing head of the Accu-Drop multidropper, thus preventing the delivery of multiple drops. A metal plate was drilled so that 25 cartridges could be positioned to inoculate simultaneously 25 compartments in a divided petri dish.
Whole Microorganisms Studied by Pyrolysis-Gas Chromatography-Mass Spectrometry: Significance for Extraterrestrial Life Detection Experiments
Authors: Simmonds Peter G.
Published: December 2020

Pyrolysis-gas chromatography-mass spectrometric studies of two microorganisms,
Micrococcus luteus
and
Bacillus subtilis
var.
niger
, indicate that the majority of thermal fragments originate from the principal classes of bio-organic matter found in living systems such as protein and carbohydrate. Furthermore, there is a close qualitative similarity between the type of pyrolysis products found in microorganisms and the pyrolysates of other biological materials. Conversely, there is very little correlation between microbial pyrolysates and comparable pyrolysis studies of meteoritic and fossil organic matter. These observations will aid in the interpretation of a soil organic analysis experiment to be performed on the surface of Mars in 1975. The science payload of this landed mission will include a combined pyrolysis-gas chromatography-mass spectrometry instrument as well as several “direct biology experiments” which are designed to search for extraterrestrial life.
Reversible Inhibition of Spore Germination by Alcohols
Authors: Trujillo Ralph , Laible Nancy
Published: December 2020

Low levels of alcohols have been found to inhibit the process of spore germination. The extent of germination is dependent upon the concentration of alcohol present in the germinating medium. This inhibition is reversible since removal of the alcohol from the spore environment allows germination to proceed.
Evaluation of Systemic Antifungal Agents in X-Irradiated Mice
Authors: Gordee Robert S. , Matthews Thomas R.
Published: December 2020

The effect of X irradiation on the survival time of animals experimentally infected with pathogenic fungi was studied, and the activity of antifungal agents in pre-irradiated hosts was evaluated. A 24-hr preinfection dose of X irradiation decreased the survival time of mice infected with
Cryptococcus neoformans
and
Histoplasma capsulatum
to a greater extent than
Candida albicans
or
Blastomyces dermatitidis
infections. Exposure to 400 r caused a significant reduction in the variation (S
2
) survival time of
C. albicans
or
H. capsulatum
mouse infections. A single 100-mg/kg dose of 5-fluorocytosine or amphotericin B administered within 24 hr postinfection significantly extended the survival time of mice infected with
C. albicans.
Delayed treatment with amphotericin B was effective against
C. neoformans
infections. Four 50-mg/kg doses of 5-fluorocytosine were more effective than a single 200-mg/kg dose against
C. neoformans
infections. A single dose of amphotericin B provided significant protection when administered 48 hr postinfection against
B. dermatitidis
in preirradiated mice. A single dose of saramycetin 48 hr postinfection was highly effective against
H. capsulatum
mouse infections. A 100-mg/kg dose of amphotericin B was only effective against this fungal pathogen when administered within 8 hr postinfection. In vivo activity of the antifungal agents studied was detected within 8 to 14 days. The relative in vivo activity of several antifungal agents indicated the importance of considering their individual pharmacological properties for optimum effectiveness. The experimental model used in this study should be useful for the detection and for the preclinical evaluation of new antifungal agents.
Examination of Virus-Infected Cultured Cells by Scanning Electron Microscopy
Authors: Aranyi Catherine , Fenters James , Tolkacz Vivian
Published: December 2020

The scanning electron microscope (SEM) was used to detect changes in morphology of BSC-1 cells after infection with vesicular stomatitis virus (VSV) or herpes simplex virus. The morphological changes of the infected cells were related to the length of time of infection and to the virus used. Extensive alteration to the cytoplasm could be seen 24 and 48 hr after infection with 10 and 320 TCID
50
of VSV. Within 24 hr after infection with 1 TCID
50
of herpes simplex, a few nuclei were swollen. However, 72 hr after infection with 100 TCID
50
of herpesvirus, many nuclei were swollen and appeared in large aggregates, probably representing formation of a polykaryocyte. Corresponding samples stained with May-Grunwald-Giemsa were observed in the light microscope and morphological changes were compared to those seen with the SEM.
Utilization of
n
-Alkanes by
Pullularia pullulans
Authors: Merdinger Emanuel , Merdinger Raidie P.
Published: December 2020

Pullularia pullulans
was tested for its ability to utilize a series of
n
-alkanes for growth. It utilized hydrocarbons containing higher C-numbers (13, 14, 16, and 18) to a greater degree than those containing lower numbers; in addition, an induction phenomenon was noted. Gas-liquid and thin-layer chromatography of ether extracts of the growth media revealed that oleic and palmitic acids were formed from tridecane, tetradecane, hexadecane, and octadecane.
Continuous-Flow Ultracentrifugation of Canine Distemper Virus and Infectious Canine Hepatitis Virus
Authors: Elliott John A. , Ryan Wayne L.
Published: December 2020

The use of a Spinco L-4 zonal centrifuge with the B-XVI continuous-flow rotor for the purification of canine distemper and infectious canine hepatitis viruses is described. Up to 68 liters of virus was processed at one time. Infectious canine hepatitis virus was found to band at 39% sucrose and canine distemper virus banded between 32 and 48% sucrose. The virus was concentrated 10-fold, and the purity of the virus, as measured by protein concentration, was increased by 99%.
Growth Stimulants in Plant Extracts for
Leuconostoc citrovorum
Authors: Stamer J. R. , Stoyla B. O.
Published: December 2020

The growth of
Leuconostoc citrovorum
ML 34, an isolate associated with the malo-lactic fermentation of wine, was stimulated in part by grape, orange, cabbage, and tomato juices. The stimulatory activity of tomato serum was associated with the carbohydrate fraction. Further purification of the fraction showed that fructose was the factor responsible for initiating growth. In addition to fructose, the organism required CO
2
for establishing growth. Saturated CO
2
atmosphere and catalytic amounts of fructose served as substitutes for plant extracts in a complex glucose medium.
Growth of
Pseudomonas fluorescens
with Sodium Maleate as a Carbon Source
Authors: Perry John T. , Edwards Victor H.
Published: December 2020

The growth of
Pseudomonas fluorescens
(ATCC 11150) on sodium maleate was observed, and the composition of the media was monitored in batch culture. Utilization of the maleate as the sole organic carbon source proceeded by stepwise conversion to fumarate and then to malate. Respiration rates of
P. fluorescens
on maleate, mixtures of maleate and fumarate salts, and mixtures of maleate and malate salts were measured. Complex effects, possibly due to a change in metabolic mechanism, were observed.
Comparison of Methods for Removal of Nonspecific Inhibitors of Arbovirus Hemagglutination
Authors: Monath Thomas P. C. , Lindsey Helen S. , Nuckolls James G. , Chappell W. A. , Henderson Brian E.
Published: December 2020

Human sera were treated with kaolin, acetone, and dextran sulfate to determine the best method for removing nonspecific hemagglutination inhibitors. Results indicated that on surveys for group A, group B, and some group C arbovirus HI antibodies, dextran sulfate treatment of sera could be used effectively. This method, however, has limited usefulness for detecting HI antibody for a number of arboviruses, particularly some members of the Bunyamwera supergroup since nonspecific inhibitors for these antigens were not completely removed. HI antibodies in sera drawn early after dengue and Venezuelan equine encephalitis infection were detected more readily after dextran sulfate treatment than after kaolin treatment. Kaolin, but not dextran sulfate, was shown to remove antibody from IgM fractions of sera.
Effect of
p
H on the Activity of Erythromycin Against 500 Isolates of Gram-Negative Bacilli
Authors: Lorian Victor , Sabath L. D.
Published: December 2020

Erythromycin was found to be a more effective inhibitor of gram-negative bacilli in alkaline medium than in neutral or acid medium. A definite effect was noted with all of 500 recent clinical isolates of
Escherichia coli, Klebsiella-Enterobacter, Pseudomonas aeruginosa
, and
Proteus mirabilis
studied, but it was most striking with
E. coli
. At
p
H 8.5 all strains, except for 14% of those of
P. mirabilis
, were inhibited by concentrations of erythromycin readily achieved in urine with common therapeutic doses.
Microcount Method for Petrolatum-Based Topical Ointments Containing Waxes
Authors: Tsuji Kiyoshi , Robertson John H.
Published: December 2020

A practical solvent system for the detection of microorganisms in topical ointments has been developed. The method involves dissolving 0.5 g of topical ointment in 50 ml of a solvent mixture (92 parts isopropyl myristate, 6 parts carbon disulfide, and 2 parts xylene) and filtering it through a 0.45-μm membrane filter. Residual solvent is then washed from the filter pad with 200 ml of sterile 0.5% Brain Heart Infusion broth containing 0.1% Tween 80. The filter pad is then removed and placed on a petri plate containing Trypticase Soy Agar medium. The petri plates thus prepared are then incubated at 37 C for 7 days, and the colonies produced are then counted. The toxicity of the solvent mixture was determined against
Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella newington
, and spores of
Bacillus subtilis
and was found to be less toxic than the heat-sterilized isopropyl myristate and comparable to the filter-sterilized isopropyl myristate.
Dry-Heat Destruction of
Bacillus subtilis
Spores on Surfaces: Effect of Humidity in an Open System
Authors: Drummond D. W. , Pflug I. J.
Published: December 2020

Bacillus subtilis
var.
niger
spores were tested for dry-heat resistance on stainless-steel strips hung in an oven. Heat resistance was dependent on the relative humidity before and during treatment, which in turn affected the water content of the spores. Higher humidities increased the heat resistance of the spores.
D
-values ranged from 16.1 min for spores conditioned at <2% relative humidity (RH) and treated at 0.34% RH to 37.6 min for spores conditioned at 89% RH and treated at 1.1% RH. The
y
-intercept of the regression line ranged from 6.94 × 10
4
for spores conditioned and treated at the low humidities to 2.00 × 10
5
for spores conditioned at 89% RH and treated at 0.34% RH. For a constant value of
N
0
, the
y
-intercept appears to be lowered by low-humidity conditions. The statistic log
y
0
/log
N
0
is used to measure the downward displacement of the regression line. Values obtained in this experiment range from 0.90 for spores conditioned at <2% RH and treated at 0.34% RH to 1.04 for spores conditioned at <2% RH and treated at 1.1% RH. A combination of linear regression and analysis of variance methods was used for data analysis. The former estimates
D
-values and
y
-intercepts, whereas the latter is sensitive to differences between treatments.
Production of Specific Agglutinins for Mycobacteria in Peritoneal Fluid of Mice
Authors: Thoen Charles O. , Karlson Alfred G.
Published: December 2020

Specific agglutinins were produced in ascitic fluid of mice by intraperitoneal injection of certain mycobacteria suspended in Freund's incomplete adjuvant.
Amino Acid-Induced Inhibition and Stimulation of
Saccharomyces carlsbergensis
Authors: Waller James R.
Published: December 2020

The response pattern of
Saccharomyces carlsbergensis
(ATCC 9080) to pantothenic acid in Atkin's medium was changed dramatically by adding small amounts of casein hydrolysate (0.032 to 0.32 mg/ml) to the assay medium. Under static, mildly anaerobic conditions, growth at low pantothenic acid levels was reduced by 54 to 69%, whereas at saturating or near saturating pantothenate concentrations marked stimulation of growth (up to 41%) was observed. Under aerobic conditions, inhibition but not stimulation of growth occurred. It is recommended that Atkin's medium for the assay of pantothenic acid with
S. carlsbergensis
(ATCC 9080) be modified to include 0.6% acid-hydrolyzed casein (Vitamin Free Casamino Acids, Difco) to prevent erroneous growth responses, which may result if significant amounts of amino acids are present in natural materials being assayed for this vitamin.
Rapid Detection of Small Numbers of Airborne Bacteria by a Membrane Filter Fluorescent-Antibody Technique
Authors: Jost Rolf , Fey Hans
Published: December 2020

Bacteria from stirred settling aerosols were recovered and identified by a rapid fluorescent-antibody technique previously described by Danielsson. Calibrated air samples from
Serratia marcescens
aerosols were drawn through a Millipore aerosol filter holder fitted out with a nonfluorescent membrane filter (type HAB 047). With the aid of a high-power incident-light ultraviolet microscope, the individual bacterial cells, trapped on the filter, could be inspected after staining with appropriate conjugate on the filter surface.
Effect of Trace Elements on Citric Acid Fermentation by
Aspergillus niger
Authors: Sánchez-Marroquín A. , Carreño R. , Ledezma M.
Published: December 2020

Citric acid yields of 98.7% (sugar consumption basis) were reached in shaker flasks with mutant UV-ET-71-15 of
Aspergillus niger
in a resin-treated sucrose medium of the following composition (g/100 ml): sucrose, 14.0; NH
4
NO
3
, 0.20; KH
2
PO
4
, 0.10; MgSO
4
·7H
2
O, 0.025; and (mg/liter): FeSO
4
, 0.15 to 0.75; ZnSO
4
, 0.10; and CuSO
4
, 0.01. Yields of 75% were obtained in medium with resin-treated clarified syrup and 68% with ferrocyanide-treated blackstrap molasses. Optimal conditions included selection of appropriate pellets as inoculum at 3%,
p
H of 4.5, temperature at 30 C, agitation at 250 rev/min, and fermentation time of 8 days. The mutant tolerated high concentrations of trace elements.
Gel Diffusion Method for Determining the Titer of Duck Hepatititis Virus
Authors: Gabridge Michael G. , Newman John P.
Published: December 2020

Apparatus necessary for a quantitative gel diffusion and precipitation assay of duck hepatitis virus was designed and constructed.
Possible Influence of Antibiotic Therapy on Usefulness of Metabolic Inhibition Test for Diagnosis of
Mycoplasma pneumoniae
Infections
Authors: Smith Thomas F. , Herrmann Ernest C.
Published: December 2020

Certain antibiotics, if in serum, simulate specific antibody in the metabolic inhibition test for diagnosis of
Mycoplasma pneumoniae
infections. This effect is not eliminated by presence of serum or heat treatment.
Identification of a Pea Component Stimulatory for Heat-Stressed Putrefactive Anaerobe 59-123 Spores
Authors: Ashton D. H.
Published: December 2020

Pea extract contains a factor which improves recovery counts of heat-stressed putrefactive anaerobe spores in a complex medium up to threefold. The factor is heat-stable and nondialyzable. Most of the active principle is found in the precipitate which forms during storage of pea extract at 4 C. The precipitate disperses upon heating, is high in starch content, and retains activity after extraction with organic solvents and water. Treatment of pea extract with α-amylase results in complete destruction of the active principle. These observations indicate that starch is the factor in pea extract responsible for increased recovery counts of heat-stressed putrefactive anaerobe spores.
Lipoprotein Inhibitor of Newcastle Disease Virus from Chicken Lung
Authors: Allen Richard G. , Barrett James T. , Campbell Benedict J.
Published: December 2020

A lipoprotein inhibitor of Newcastle disease virus was obtained from chicken lung tissue by means of dilute alkaline extraction procedures. The inhibitor was further purified by ammonium sulfate fractionation, isoelectric precipitation, and density gradient centrifugation. The purified lipoprotein inhibited active Newcastle disease virus hemagglutination at a concentration of 2.0 μg/ml which represented a 30-fold purification over the original extract. Infection of chicken embryo fibroblasts by Newcastle disease virus was also inhibited by the purified lipoprotein, the degree of inhibition depending upon the inhibitor-to-virus ratio. Chemical analysis of the purified inhibitor provided a composition of 72% lipid, 26% protein, and 3% carbohydrate, although some compositional variation was observed from one preparation to another. The chloroform-soluble lipids were shown to contain 40 to 50% phospholipid and 10 to 20% cholesterol; of the fatty acids recovered from the saponified lipoprotein, 39% was palmitic, 22% oleic, and 17% stearic. Careful analyses of large quantities of the inhibitor revealed a small (0.84%) but significant content of sialic acid. Removal of sialic acid from the lipoprotein by means of digestion with neuraminidase produced a sharp diminution in inhibitory properties. A delipidized form of the inhibitor was obtained by ether extraction, and this material produced a single broad band of precipitate in gel immunodiffusion tests.
In Vitro Studies of α-Carboxyl-3-Thienylmethyl Penicillin, a New Semisynthetic Penicillin
Authors: Bodey Gerald P. , Deerhake Beverly
Published: December 2020

The activity of a new semisynthetic penicillin, α-carboxyl-3-thienylmethyl penicillin (BRL-2288) was determined against 535 clinical isolates of gram-negative bacilli, by using the tube dilution technique. Nearly 80% of isolates of
Proteus
spp. were inhibited by 3.12 μg or less of this antibiotic per ml. BRL-2288 was as active as ampicillin against
Escherichia coli.
It was slightly more active than carbenicillin or 6-(
d
-α-sulfoaminophenylacetamido)-penicillanic acid against
Pseudomonas
sp., with over half of the isolates being inhibited by 50 μg or less of BRL-2288 per ml. Isolates of
Klebsiella
sp. were routinely resistant to this antibiotic. The drug was bactericidal against most sensitive organisms. BRL-2288 was less active against large inocula. A strain of
Pseudomonas
sp. which developed resistance to carbenicillin also developed resistance to BRL-2288 simultaneously.
Labile Serum Factor and Its Effect on Arbovirus Neutralization
Authors: Chappell W. A. , Sasso D. R. , Toole Roberta F. , Monath Thomas P.
Published: December 2020

Enhancement of neutralization of Sindbis, Venezuelan equine encephalitis, Eastern equine encephalitis, Western equine encephalitis, and St. Louis encephalitis viruses by labile serum factor (LSF) in human serum and plasma was demonstrated. Human serum and plasma could be diluted 1:8 and 1:16 and still retain some LSF activity. Satisfactory storage temperatures for retention of LSF activity were −20 or −56 C. Repeated freeze-thaw cycles of serum did not alter LSF activity, but the activity was completely eliminated by heating at 56 C for 5 min. LSF of human serum equally enhanced neutralization by Sindbis immune mouse and rabbit sera; these results suggest a lack of species specificity. Rehydrated lyophilized gunea pig complement did not restore LSF activity to heated human plasma. Serum components responsible for LSF activity were not dialyzable. Discovery of fresh serum without LSF activity established the need to pretest all sera used as LSF sources.
Glycerol Ester Hydrolase Activity of
Microbacterium thermosphactum
Authors: Collins-Thompson D. L. , Sørhaug T. , Witter L. D. , Ordal Z. J.
Published: December 2020

Microbacterium thermosphactum
possesses a significant glycerol ester hydrolase (lipase, EC 3.1.1.3) activity and a weak but definite carboxylic ester hydrolase (esterase, EC 3.1.1.1) activity. Harvested whole cell preparations contained 53 units of lipase activity with tripropionin as the substrate. This activity decreased with an increasing chain length of fatty acid in the triglyceride to 13 units with trilaurin as the substrate and no activity with tripalmitin. Maximum lipase activity was found at a temperature of 35 to 37 C and at a
p
H of 7.1 to 7.3. Lipase activity was associated with three different protein peaks when the protein of cell-free extract was fractionated by polyacrylamide gel electrophoresis.
High-Yield Method for Dispersing Simian Kidneys for Cell Cultures
Authors: de Oca H. Montes , Probst P. , Grubbs R.
Published: December 2020

A technique for dispersion of animal tissue cells is described. The proposed technique is based on the concomitant use of trypsin and disodium ethylenediamine tetraacetate (EDTA). The use of the two dispersing agents (trypsin and disodium EDTA) markedly enhances cell yield as compared with the standard cell dispersion methods. Moreover, significant reduction in the amount of time required for complete tissue dispersal, presence of a very low number of nonviable cells, less cell clumping, and more uniform monolayer formation upon cultivation compare favorably with the results usually obtained with the standard trypsinization technique.
Comparison of Various Methods for Preparation of Viral Serological Antigens from Infected Cell Cultures
Authors: Schmidt Nathalie J. , Lennette Edwin H.
Published: December 2020

In efforts to prepare more potent and sensitive viral serological antigens, several aspects of the production of antigens from infected cell cultures were studied. Antigens derived from whole, infected culture material and from the cellular and fluid phases were compared. Freezing and thawing, sonication, and alkaline buffer extraction were compared for effectiveness in releasing antigen from host cells. The effect of the multiplicity of infection on titers of viral antigens produced in cell cultures was studied. Generally, higher titered antigens were derived from the infected cells than from the culture fluids, but for certain viruses complement-fixing (CF) antigens derived from the culture fluids gave higher antibody titers than did cell-associated antigens. With each virus-host cell system studied, treatment with alkaline buffers extracted appreciable amounts of CF antigen from the host cells, but in some instances more antigen was released by freezing and thawing or by sonication. Extraction of infected cells with alkaline buffers was not a satisfactory method for preparation of hemagglutinating (HA) antigens for any of the viruses studied. The highest-titered HA antigens were produced from infected cells disrupted by freezing and thawing or sonication. The highest titered CF and HA antigens were produced from cell cultures infected at multiplicities of one or greater. Complement-fixing antigens produced by infecting cells in suspension and then planting had lower titers than antigens produced in parallel by infecting developed monolayers. Optimal methods are summarized for preparation of serological antigens to a variety of viruses of man.
Comparison of the Streptozyme Test with the Antistreptolysin O, Antideoxyribonuclease B, and Antihyaluronidase Tests
Authors: Klein George C. , Jones Wallis L.
Published: December 2020

The streptozyme test was compared with the antistreptolysin O (ASO), antideoxyribonuclease B (ADN-B), and antihyaluronidase (AH) tests. One hundred and twenty-seven human serum specimens were tested by each of the four tests. The streptozyme test detected more specimens with elevated titers than any single test; however, it was not as effective as the combination of the ASO and ADN-B tests. The streptozyme test appears to be particularly useful for laboratories which rely solely on the ASO test for serological evidence of a streptococcal infection. The test can be used in these laboratories to screen all specimens with low ASO titers (<170) for the detection of ADN, AH, antinicotinamide adenine dinucleotidase, and antistreptokinase.
Quantitative Micro-Complement Fixation Test
Authors: Marucci A. A. , Fuller T. C.
Published: December 2020

A quantitative micro-complement fixation test capable of detecting nanogram quantities of antigen is described. The test is simple to perform and is highly reproducible. Typical results from three antigen-antibody systems are given.
Characterization of Growth Stimulants in Corn Steep for Lactic Streptococci
Authors: Johnson E. C. , Gilliland S. E. , Speck M. L.
Published: December 2020

The production of acid in milk cultures of lactic streptococci was stimulated by the addition of corn steep liquor. Separation by ion-exchange and paper chromatography indicated the presence of four major stimulatory components in the corn steep. Some variation was noted in the response of the lactic streptococci to the individual stimulatory components. The four components were further purified by paper and column chromatography. One of the four stimulatory components stained positively on chromatograms with ninhydrin. The remaining stimulatory components were detectable only by bioautography. All four components were unstable to acid hydrolysis and absorbed ultraviolet light between 230 and 275 nm in aqueous solution. The stimulatory components did not contain pentoses, suggesting that they were not nucleotides or nucleosides; however, they might be purine or pyrimidine bases.
Combined Action of Sulfamethoxazole, Trimethoprim, and Ethylenediaminetetraacetic Acid on
Pseudomonas aeruginosa
Authors: Rawal B. D. , Owen W. R.
Published: December 2020

Potentiation of the sulfamethoxazole-trimethoprim combination by ethylene-diaminetetraacetic acid inhibited, in vitro, four strains of
Pseudomonas aeruginosa
which were resistant to the sulfamethoxazole-trimethoprim combination alone.
Serological Diagnosis of Pullorum Disease with the Microagglutination System
Authors: Williams J. E. , Whittemore A. D.
Published: December 2020

The application of a tetrazolium-stained
Salmonella pullorum
antigen in the microagglutination test is described and compared with the macroscopic tube agglutination test for detecting carriers of pullorum disease and fowl typhoid in chickens. Titers revealed by both testing procedures are similar; however, the microagglutination test is preferred because of the savings in time, space, and cost.
Relative Susceptibility of Acid-Fast and Non-Acid-Fast Bacteria to Ultraviolet Light
Authors: Collins F. M.
Published: December 2020

Mycobacterium tuberculosis
strain Erdman,
M. bovis
(BCG), and
M. phlei
showed a 1- to 2-log drop in viability after exposure to ultraviolet light compared to a 5-log drop over the same period for
Staphylococcus albus, Listeria monocytogenes, Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis
, and
Serratia marcescens. L. monocytogenes
showed an initial resistance to ultraviolet inactivation, but later the inactivation rate increased sharply. The significance of these findings with regard to the use of
S. marcescens
as a test organism for determining the bactericidal efficiency of ultraviolet lamps used to sterilize equipment contaminated with tubercle bacilli is discussed.
Characterization of
Pseudomonas
Species Isolated from Clinical Specimens
Authors: Gilardi G. L.
Published: December 2020

More than 90 morphological and physiological characters of 227 strains of pseudomonads isolated from clinical specimens and 16 reference strains are described. The clinical isolates included
P. aeruginosa
(apyocyanogenic),
P. fluorescens, P. putida, P. pseudomallei, P. cepacia, P. acidovorans, P. alcaligenes, P. pseudoalcaligenes, P. stutzeri, P. putrefaciens, P. maltophilia
, and
P. diminuta.
Bacterial Metabolism of Arylsulfonates
Authors: Ripin Marilyn J. , Noon Kerry F. , Cook Thomas M.
Published: December 2020

Pseudomonas testosteroni
H-8 utilizes as sole carbon source benzene sulfonate (BS),
p
-toluene sulfonate (pTS), and ethylbenzene sulfonate (EBS) but not higher homologs. Growth on BS was rapid (generation time, 3 hr) and efficient (
Y
= 57), and resulted in accumulation of sulfate. As the culture is acid-sensitive, the medium must be heavily buffered to permit extensive growth. The BS oxidase system is inducible. Cells grown on BS, but not glutamate, oxidized BS, pTS, or EBS without lag (QO
2
= 50 to 100). Oxygen uptake on BS is temperature-dependent and sensitive to cyanide. Complete oxidation of 1 μmole of BS consumed approximately 5.7 μmoles of oxygen.
New Quantitative, Qualitative, and Confirmatory Media for Rapid Analysis of Food for
Clostridium perfringens
Authors: Shahidi Syed A. , Ferguson Alphonza R.
Published: December 2020

A selective and differential medium, Shahidi-Ferguson Perfringens agar (SFP agar), and a confirmatory medium, lactose-motility agar (LM agar), were developed for the enumeration and identification of
Clostridium perfringens
in foods. These media provide a rapid, specific, and direct diagnosis of
C. perfringens.
SFP agar contains sodium metabisulfite and ferric ammonium citrate to demonstrate H
2
S production and egg yolk to demonstrate lecithinase production by
C. perfringens.
On SFP agar,
C. perfringens
produces black colonies, 2 to 3 mm in diameter, surrounded by zones of opaque precipitate. The typical colonies are confirmed on LM agar. Enumeration and identification are completed within 48 hr. All of the ingredients of SFP agar are stable to heat and storage conditions. SFP agar also contains two antibiotics, kanamycin and polymyxin B, which are inhibitory to many bacteria commonly occurring in foods. A comparative study of SFP agar and noninhibitory media showed that SFP agar did not inhibit any of the 16 strains of
C. perfringens
tested. Recovery of
C. perfringens
added to foods averaged 90.6% for SFP agar as compared with 69.8% for sulfite polymyxin-sulfadiazine (SPS) agar (BBL) and 60.2% for SPS agar (Difco). The colonies on the SFP agar, were much larger and were consistently black. Of 464 food samples tested,
C. perfringens
was found in 27 samples with SFP agar and in 5 samples with SPS agar (Difco), with a recovery ratio considerably higher on SFP agar. SFP agar is a more specific presumptive medium for the enumeration of
C. perfringens
and in conjunction with LM agar should save considerable time, effort, and materials toward the final identification of the species.
Listeria monocytogenes
in Nature
Authors: Welshimer H. J. , Donker-Voet Jeanette
Published: December 2020

Samples from 12 farms were examined during two successive spring and early autumn seasons.
L. monocytogenes
was isolated from vegetation or soil taken from 11 of the 12 farms and from 6 of the 7 nonagricultural sites. A total of 27 strains were isolated from the 19 sites. The organism was not isolated from any of the autumn collections.