bluuebunny/crossref_metadata_2025 huggingface dataset:
L-Asparaginase Synthesis by
Erwinia aroideae
Authors: Liu F. S. , Zajic J. E.
Published: December 2020

Maximum L-asparaginase activity was obtained when 1.0% lactose and 1.5% yeast extract were supplied as carbon and nitrogen sources, respectively. Glucose inhibited the enzyme formation. The diauxie phenomenon was observed with
Erwinia aroideae
NRRL B-138 grown in a medium containing glucose and lactose.
Efficiency of
Salmonella
Isolation from Meat-and-Bone Meal of One 300-g Sample Versus Ten 30-g Samples
Authors: Huhtanen C. N. , Naghski J. , Dellamonica E. S.
Published: December 2020

Twenty-five meat-and-bone meal samples were analyzed for salmonellae, comparing a single 300-g to ten 30-g samples. Seventeen were positive using the larger sample; eighteen were positive with the smaller. The 300-g sample showed a significantly higher (
P
< 0.01) percentage of confirmed salmonellae at 2 days of incubation than at 1 day. The ten 30-g samples did not show changes at 2 days. At 2 days, the 30-g samples showed significantly fewer confirmed salmonellae than the 300-g sample; however, there was no difference at 1 day. Of 1,417 presumptive colonies picked, 1,215 (85.7%) were lysine decarboxylase-positive and 1,152 (81.3%) were agglutinated by one of the somatic antisera. There were no significant differences in diversity or total numbers of different somatic groups between the large and small samples.
Studies on Variants of
Bacillus stearothermophilus
Strain NCA 1518
Authors: Humbert R. D. , DeGuzman Anselma , Fields M. L.
Published: December 2020

The heat resistance, fermentation reactions, nutritional requirements, and phage sensitivity of 18 selected morphological variants of
Bacillus stearothermophilus
NCA 1518 were studied. It was found that when smooth variants mutated to rough colonial morphology, there was no concurrent change in fermentation reactions, nutritional requirements, or heat resistance. The smooth variant, and the rough mutants derived directly from it, presented a uniform pattern of biochemical capabilities which differed from the pattern presented by the rough variants isolated from the same stock culture. This led to the conclusion that the smooth and rough types previously observed in stocks of
B. stearothermophilus
NCA 1518 either were carried in the stock since the original isolation or represent a very profound and uncommon mutation, or that one of the variants has been introduced into the stock culture from an extraneous source sometime in the past.
Interrelationship of Heat and Relative Humidity in the Destruction of
Clostridium botulinum
Type E Spores on Whitefish Chubs
Authors: Pace Paul J. , Krumbiegel Edward R. , Wisniewski Henry J.
Published: December 2020

Heat destruction of types B and E
Clostridium botulinum
spores on whitefish chubs was observed to be dependent upon the relative humidity (RH) in the chamber in which fish were heated. Experimental conditions were designed to simulate those attainable in commercial fish-smoking plants. Low numbers of type E spores were destroyed with regularity, within 30 min, on fish which were held at an internal temperature of 77 C (170.6 F) in an atmosphere of at least 70% RH. However, an internal temperature of 82 C (179.6 F) and a minimum RH of 70% were required to destroy several hundred thousand type E spores. Quantitative estimates of spore destruction were arrived at with a modified most probable number procedure. Type E spore populations were reduced by 2 to 4 logarithms at 77 C (170.6 F), by 5 to 6 logarithms at 82 C (179.6 F), and by more than 6 logarithms at 88 C (190.4 F) when fish were heated in an atmosphere of 70% RH. A 5 to 6 logarithm reduction of spores was also observed when fish inoculated with type B spores were processed at 82 C (179.6 F) in an atmosphere of 70% RH.
A Method to Render Unstained Mycobacterial Smears Safe for Storage or Shipment
Authors: Blair E. B. , Bretherton W. W. , Tull A. H.
Published: December 2020

Sterilization and optimal staining of
Mycobacterium tuberculosis
in sputum smears was accomplished by heating at 65 C for 30 min followed by exposure for 10 min to 10% formaldehyde fumes.
Preliminary Report: a System for Typing
Salmonella thompson
Authors: Gershman M.
Published: December 2020

A system is described for the phage typing of
Salmonella thompson
. The system is based upon a number of bacteriophages that were isolated from sewage.
Production of Staphylococcal Enterotoxin A on Cellophane-Over-Agar
Authors: Minor T. E. , Marth E. H.
Published: December 2020

Up to approximately 50 μg of staphylococcal enterotoxin A per plate was produced by cellophane-over-agar cultures. Enterotoxin was determined by a latex agglutination technique.
Purification of Large Quantities of
Coxiella burnetii
Rickettsia by Density Gradient Zonal Centrifugation
Authors: Canonico Peter G. , Van Zwieten Matthew J. , Christmas William A.
Published: December 2020

The purification of large quantities of inactivated, phase II
Coxiella burnetii
by isopycnic zonal centrifugation for use as diagnostic antigen and as a vaccine is described. The fractionation of egg yolk sac-derived
C. burnetii
vaccine resulted in the separation of two distinct populations of organisms, each devoid of microscopically and serologically recognizable components of egg yolk sac. One population of organisms, characterized by an equilibrium density of 1.240, was rod shaped (1.0 by 0.5 μmole) with a thick, densely strained wall and prominent central body. The second population, with an equilibrium density of 1.280, had a coccobacillary shape (approximately 1 μmole in diameter), granular, sometimes fibrillar cytoplasm, thin cellular walls, and lacked a prominent nucleoid.
Factors Affecting Comparative Resistance of Naturally Occurring and Subcultured
Pseudomonas aeruginosa
to Disinfectants
Authors: Carson L. A. , Favero M. S. , Bond W. W. , Petersen N. J.
Published: December 2020

A strain of
Pseudomonas aeruginosa
was isolated in pure culture from the reservoir of a hospital mist therapy unit by an extinction-dilution technique; its natural distilled water environment was used as a growth and maintenance medium. After a single subculture on Trypticase soy agar, the strain showed a marked decrease in resistance to inactivation by acetic acid, glutaraldehyde, chlorine dioxide, and a quaternary ammonium compound when compared with naturally occurring cells grown in mist therapy unit water. The following factors were observed to affect the relative resistances of naturally occurring and subcultured cells of the
P. aeruginosa
strain: (i) temperature at which the cultures were incubated prior to exposure to disinfectants, (ii) growth phase of the cultures at the time of exposure to disinfectants, (iii) nature of the suspending menstruum for disinfectants, and (iv) exposure to fluorescent light during incubation of inocula prior to testing. The applied significance of these findings may alter the present concepts of disinfectant testing as well as routine control procedures in the hospital environment.
Simple Dye Release Assay for Determining Cellulolytic Activity of Fungi
Authors: Poincelot Raymond P. , Day Peter R.
Published: December 2020

A colorimetric assay, based on the release of dye from a paper substrate, is described as a simple and rapid means of detecting cellulolytic activity. It is readily adaptable to rapidly screening in situ large numbers of fungal liquid cultures. Since it is a nondestructive assay, samples can be recovered for later use.
Virus in Water. II. Evaluation of Membrane Cartridge Filters for Recovering Low Multiplicities of Poliovirus from Water
Authors: Hill William F. , Akin Elmer W. , Benton William H. , Metcalf Theodore G.
Published: December 2020

The efficiency of a Millitube MF cartridge filter, a membrane filter, for recovery of poliovirus from 100-gal volumes of both fresh (tap) and estuarine water was determined. In the high multiplicity of virus input-output experiments, recovery of 97% or greater of input virus was achieved in both types of water when the final concentration of divalent cation as Mg
2+
was 1,200 μg/ml and the
p
H was 4.5. Virus was effectively eluted from the membrane cartridge with 5× nutrient broth in 0.05 M carbonate-bicarbonate buffer at
p
H 9.0. Four elutions of 250 ml each were used. In the low multiplicity of virus input-output experiments under the same cationic and
p
H conditions, up to 67% of the input virus was recovered when the virus was further concentrated from the eluates by the aqueous polymer two-phase separation technique. The volume reduction was 126,000-190,000 to 1. The use of the combined techniques, i.e., membrane adsorption followed by aqueous polymer two-phase separation, provided a highly sensitive, simple, and remarkably reliable sequential methodology for the quantitative recovery of poliovirus occurring at multiplicities as low as 1 to 2 plaque-forming units per 5 gal of water.
Studies of Antigens for Complement Fixation and Gel Diffusion Tests in the Diagnosis of Infections Caused by
Brucella ovis
and Other
Brucella
Authors: Myers Donald M. , Jones Lois M. , Varela-Diaz Victor M.
Published: December 2020

Sonically treated and saline-extracted antigens of
Brucella ovis, B. canis, B. abortus
, and
B. melitensis
were compared in gel diffusion, complement fixation, and serum absorption tests. All the sonically extracted antigens showed cross-reactions with sera from animals infected or immunized with these species, whereas the saline-extracted antigens were specific for the surface of the rough or smooth colonial phase of the species or strain. The saline-extracted antigens of
B. ovis
and
B. melitensis
were both eluted as a single peak in the void volume by Sephadex G-200 column chromatography, in gel diffusion had staining characteristics of lipoproteins, but in immunoelectrophoresis showed distinct mobility patterns. Serological activity for both gel diffusion and complement fixation tests was demonstrated in the immunoglobulin G-containing fraction of sera taken from sheep 12 to 412 days after infection with
B. ovis
. The gel diffusion test with saline extract of
B. ovis
is as sensitive as the complement fixation test for the diagnosis of ram epididymitis and is more practical.
Yellow Fever Vaccine. V. Antibody Response in Monkeys Inoculated with Graded Doses of the 17D Vaccine
Authors: Mason Richard A. , Tauraso Nicola M. , Ginn Robert K. , O'Brien Thomas C. , Trimmer Roy W.
Published: December 2020

A dosage equal to or greater than approximately 3.4 Dex (decimal exponent, log
10
) weanling mouse intracerebral 50% lethal dose (LD
50
) was sufficient to elicit a yellow fever antibody response, as determined by the plaque neutralization (PN) test, in better than 90% of vaccinated rhesus monkeys. Lower dosages were progressively less effective in terms of PN titers and the PN and hemagglutination-inhibition serological conversion rates observed. A dose of between 3.4 and 4.2 Dex weanling mouse intracerebral LD
50
, or one-tenth to one times the dosage recommended for man, provided an optimal antibody response in monkeys. In rhesus monkeys, in contrast to the findings for man, pre-existing yellow fever antibody did not interfere with the antibody response to yellow fever vaccine. The PN test was felt to be a more sensitive and specific indicator of yellow fever antibody in rhesus monkeys after vaccination than the hemagglutination inhibition or complement fixation tests.
Continued Surveillance of
Serratia marcescens
Infections by Bacteriocin Typing: Investigation of Two Outbreaks of Cross-Infection in an Intensive Care Unit
Authors: Traub Walter H.
Published: December 2020

During an 8.5-month period, 198 additional isolates of
Serratia marcescens
were typed by bacteriocin sensitivity; 154 isolates were typable and were categorized according to our current system of 54 provisional bacteriocin sensitivity patterns. Two outbreaks of nosocomial infection due to
S. marcescens
occurred in our intensive care unit, involving two and five patients, respectively. The latter outbreak was caused by a strain of
S. marcescens
which was not sensitive to any of the 10 bacteriocins normally used. Therefore we developed a supplementary procedure based on bacteriocin production rather than bacteriocin sensitivity. Bacteriocin production was induced with mitomycin C, and the crude lysates were applied to 15 provisional bacteriocin indicator strains. The reverse typing procedure was necessary to determine the spread and ultimate subsidence of this particular outbreak of cross-infection.
Neisseria gonorrhoeae
: Colonial Morphology of Rectal Isolates
Authors: Kovalchik Michael T. , Kraus Stephen J.
Published: December 2020

Four principal colony types of gonococci have been previously described, and it has been shown that primary isolates from the urethra and cervix are primarily of colony types 1 and 2. In the present work, gonococcal isolates from the rectum were also shown to be predominantly colony types 1 and 2. Visualization and typing of gonococcal colonies in primary rectal isolates were facilitated by the use of medium containing vancomycin, colistin, nystatin, and, in some cases, trimethoprim lactate. Control experiments showed that these agents sometimes caused minor alterations in colonial morphology; but with knowledge of these alterations satisfactory colonial typing could be made.
Storage of Conidia of
Penicillium chrysogenum
in Liquid Nitrogen
Authors: Macdonald K. D.
Published: December 2020

Conidiated slope cultures of derivative of
Penicillium chrysogenum
Wis 54-1255 were stored at -196 or +4 C for a period of 3.5 years. After this time, the viability fell to 68% in the former case and to 4% in the latter. At the end of the experiment, 65 single conidial isolates from each series were tested for penicillin yield. Among those from conidia stored at -196 C, the spread of penicillin yields did not differ markedly from that of 65 single conidial isolates made as controls prior to storage. However, 18% of those from conidia stored at +4 C formed a subpopulation with substantially lower penicillin titers than those of control isolates. Storage at -196 C may reduce or prevent a possible source of penicillin yield decay, namely, the selection of spontaneous mutants of low titer present in small numbers in the original culture and selected, as viability decreased, by virtue of their increased longevity relative to that of the parental culture.
Hazard Inherent in Microbial Tracers: Reduction of Risk by the Use of
Bacillus stearothermophilus
Spores in Aerobiology
Authors: Sattar Syed A. , Synek E. J. , Westwood J. C. N. , Neals Pierrette
Published: December 2020

The use of a “biological tracer” forms an essential part of many aerobiological experiments. Where release of such tracers is likely to result in deliberate or inadvertent human exposure, safety becomes a primary consideration in the selection of the tracer organism. Of the three most commonly used organisms, namely
Bacillus subtilis, Escherichia coli
, and
Serratia marcescens
, only the first comes near to satisfying the need for nonpathogenicity and even it has been incriminated as a cause of human infection, sometimes with a fatal outcome. The relevant characteristics of
B. stearothermophilus
were, therefore, investigated. Because it can grow only at elevated temperatures (minimum 41 C; optimum 56 C), it should not pose a threat to human health and this view is supported by experimental evidence to be presented. It is extremely easy to grow and maintain in the laboratory, and spore suspensions are easily prepared and stored. It withstands the stresses of aerosolization and sampling and its stability in the aerosol state compares favorably with that of
B. subtilis
var.
niger
.
Mellein and 4-Hydroxymellein Production by
Aspergillus ochraceus
Wilhelm
Authors: Moore Jack H. , Davis Norman D. , Diener Urban L.
Published: December 2020

Mellein and 4-hydroxymellein are isocoumarin compounds produced by
Aspergillus ochraceus
Wilhelm. They are structurally similar to the dihydroisocoumarin moiety of ochratoxin A, a toxic metabolite of the same fungus, and they possibly have similar biological properties. Production of mellein and 4-hydroxymellein on synthetic media and natural solid substrates was determined. Several carbon and nitrogen sources supported production of these metabolites in stationary culture. Additional zinc and molybdenum increased production of both metabolites in stationary culture, but were not required for maximum production in shaken culture. Mellein and 4-hydroxymellein were produced on yellow corn, but neither was produced on wheat, peanuts, or soybeans.
Loss of Lactose Metabolism in Lactic Streptococci
Authors: McKay L. L. , Baldwin K. A. , Zottola E. A.
Published: December 2020

Lactose-negative mutants occurred spontaneously in broth cultures of
Streptococcus lactis
C
2
F. Instability of lactose metabolism was noted in other strains of
S. lactis
, in strains of
S. cremoris
, and in
S. diacetilactis
. Colonies of
S. lactis
C
2
F grown with lactose as the carbohydrate source also possessed lac
-
cells. Treatment of lactic streptococci with the mutagen acriflavine (AF) increased the number of non-lactose-fermenting variants. The effect of AF on growth and on loss of lactose-fermenting ability in
S. lactis
C
2
F was consequently further examined. The presence of AF appears to favor competitively the growth of spontaneously occurring lactose-negative cells and appears to act in the conversion of lactose-positive to non-lactose-fermenting cells. The lactose-negative mutants partially revert to lactose-positive variants which remain defective in lactose metabolism and remain unable to coagulate milk. The lactose-negative cells become dominant in continuous culture growth and provide evidence that alterations in the characteristics of starter strains can be produced by continuous culture, in this case, the complete loss in ability to ferment lactose.
Bacteremia After Genitourinary Tract Manipulation: Bacteriological Aspects and Evaluation of Various Blood Culture Systems
Authors: Sullivan N. M. , Sutter V. L. , Carter W. T. , Attebery H. R. , Finegold S. M.
Published: December 2020

A total of 300 patients undergoing various types of urological procedures was studied for incidence of bacteremia. An osmotically stabilized anaerobic broth with sodium polyanethol sulfonate (Liquoid) yielded more positive blood cultures than any other culture system and was also the best system by far for recovery of anaerobes. The membrane filter showed faster growth and, therefore, facilitated faster identification of the infecting organism. There was a 31% incidence of bacteremia in the patients having transurethral resection of the prostate, 17% in the cystoscopy group, 24% in the urethral dilation group, and 8% in the urethral catheterization group. The organisms found most frequently isolated in blood cultures were enterococci and
Klebsiella pneumoniae
. Notable were a relatively large number of anaerobes and two protoplasts. The major source of the bacteremia was previous urinary tract infection, but evidence is presented which indicates that the prostate gland and the normal urethral flora are other significant sources.
Equine Abortion (Herpes) Virus: Strain Differences in Susceptibility to Inactivation by Dithiothreitol
Authors: Klingeborn B. , Dinter Z.
Published: December 2020

The infectivity of equine abortion (herpes) virus (EAV) was inactivated by treatment with reduced dithiothreitol (DTT). According to their susceptibility to DTT, the EAV strains could be divided into three groups. The vaccine strain RAC-H (419) proved to be more resistant to DTT than all of the other 14 strains tested. The hemagglutinin of EAV was also inactivated by DTT; no strain differences were observed in this respect.
Simple Liquid Scrubber for Large-Volume Air Sampling
Authors: Buchanan Lee M. , Harstad J. Bruce , Phillips John C. , Lafferty Eugene , Dahlgren Charles M. , Decker Herbert M.
Published: December 2020

A new large-volume air sampler called the “simple liquid scrubber” is described. It can recover a high percentage of microorganisms from large volumes of air, up to 950 liters/min, and concentrate them into a small volume of liquid at a ratio of about 400,000 to 1. The principle of operation of the scrubber is based on the production of a fine mist in a rapidly moving airstream with ultimate collection of the airborne particles by impingement into the film of liquid formed upon impaction of the mist droplets on the scrubber walls. The scrubber compared favorably with the all-glass impinger (AGI-30) and the slit sampler in tests with the normal flora and with experimental aerosols of
Bacillus subtilis
var.
niger
spores.
Tentative Method for the Qualitative Detection and Quantitative Assessment of Air Contamination by Drugs
Authors: Buogo A. , Eboli V.
Published: December 2020

A method for detecting and measuring air contamination by drugs is described which uses an electrostatic bacterial air sampler, sprayers for micronizing drugs, and Mueller-Hinton medium seeded with a highly susceptible strain of
Sarcina lutea
. Three antibiotics (penicillin, tetracycline, aminosidine) and a sulfonamide (sulfapyrazine) were identified by pretreating portions of medium, showing no bacterial growth, with penicillinase or
p
-aminobenzoic acid solution and subsequently determining how both drug
-
susceptible and drug-resistant strains of
Staphylococcus aureus
were affected by this pretreatment. Quantitative determinations were also attempted by measuring the size of the inhibition zones.
Influence of Mouse Strain on the Assayed Potency (Unitage) of Tetanus Toxoid
Authors: Hardegree M. Carolyn , Pittman Margaret , Maloney Clifford J.
Published: December 2020

The assayed potency of an adsorbed tetanus toxoid C
2
, relative to the international standard for tetanus toxoid (adsorbed), varied significantly with the use of different strains of mice. The unitage was highest with NIH mice, and it was not significantly different from that with CFW mice. With CDF
1
and BALB/c mice, however, the assayed potency was significantly lower than with NIH mice. C3H mice failed to respond to the dose range of the toxoids employed with the other four strains. The significance of the influence of the mouse strain on the designation of a prescribed unit requirement for tetanus toxoid, adsorbed, relative to human efficacy is discussed.
Use of Acetamide Broth in the Isolation of
Pseudomonas aeruginosa
from Rectal Swabs
Authors: Smith Rodney F. , Dayton Sandra L.
Published: December 2020

Acetamide broth, used in conjunction with ultraviolet light scanning, was superior to Pseudosel agar in the recovery of
Pseudomonas aeruginosa
from rectal swabs both in time of recognition and total positive isolations.
Influence of Sodium Chloride on Growth of
Neisseria meningitidis
Authors: Mitzel John R. , Hunter Jack A. , Beam Walter E.
Published: December 2020

Nasopharyngeal isolates of
Neisseria meningitidis
were tested for growth on nutrient agar with and without the addition of 0.8% sodium chloride. Of the 822 strains tested, 1.3% grew on the salt-free medium, and 74.1% grew on the medium supplemented with sodium chloride.
Indirect Hemagglutination Test for Chlamydial Antibodies
Authors: Lewis Vester J. , Thacker W. Lanier , Engelman Helen M.
Published: December 2020

An indirect hemagglutination (IHA) test is described for chlamydial antibodies in psittacosis diagnostic sera; for this test tanned sheep erythrocytes sensitized with a deoxycholate extract of
Chlamydia psittaci
grown in Vero cell monolayers were used. Adaptation of the IHA test to the Microtiter system decreased sensitivity; nevertheless, the Microtiter-IHA test was more sensitive than the complement fixation test. Lymphogranuloma venereum antibodies also were detected by using antigen extracted from
C. psittaci
.
Analysis of Tobacco and Smoke Condensate for Penicillic Acid
Authors: Snow J. P. , Lucas G. B. , Harvan D. , Pero R. W. , Owens Robert G.
Published: December 2020

Gas chromatographic analyses of smoke condensate from commercial, unfiltered cigarettes spiked with penicillic acid (500 or 1,000 ppm), a reported carcinogenic substance from certain fungi, indicated approximately 3% of unchanged compound was transported in the smoke. Analysis of tobacco on which either
Aspergillus ochraceus
or
Penicillium cyclopium
was grown revealed microgram quantities of the compound. Small amounts of the material were also found in moldy tobacco from commercial storage. The results of these investigations suggest that fungi may be a source of carcinogenic compounds in tobacco and tobacco smoke.
Recovery of Protective Activity in Rabies Virus Vaccines Concentrated and Purified by Four Different Methods
Authors: Aasletad H. G. , Wiktor T. J.
Published: December 2020

Rabies vaccines concentrated by ultrafiltration, zinc acetate precipitation, ammonium sulfate precipitation, or aluminum phosphate gel adsorption were compared with respect to recovery of protective activity and purity, as measured by protective activity per mg of protein. Vaccine obtained by ammonium sulfate precipitation had a better recovery rate and a higher purity than those prepared by the other methods. Potent vaccines were also obtained by the zinc acetate precipitation and aluminum phosphate gel adsorption methods, whereas ultrafiltration was the least satisfactory method from the standpoint of vaccine purity. Chromatography of virus concentrated by ultrafiltration on a cellulose ion exchange column reduced the level of nonviral proteins. The protective activity data obtained for the vaccines examined in these experiments were found to correlate with the vaccine's complement fixation titer per mg of protein.
Catalase Test as an Aid to the Identification of
Enterobacteriaceae
Authors: Taylor Welton I. , Achanzar David
Published: December 2020

Although the catalase test has been used for many years for rapid differentiation of the genera of gram-positive organisms, little has been said about its use in the family
Enterobacteriaceae
. It was further noted that a wide variety of methods exist for the execution of the catalase test, that there is no universally accepted strength specified for the hydrogen peroxide, and that no gradations for the vigor and speed of the reaction have been mentioned. Under the conditions of the clinical laboratory, we have developed a simple, rapid, and accurate method for the catalase test that has been of great value as an aid in the identification of the
Enterobacteriaceae
. With 3% H
2
O
2
, it was observed that
Serratia, Proteus
, and
Providencia
were vigorous catalase reactors. Only
Salmonella
and rare
Escherichia, Enterobacter
, and
Klebsiella
isolates were moderate catalase reactors.
Escherichia
and
Shigella
strains were mostly nonreactive, with less than one-third weekly (+) reactive, whereas most
Enterobacter
strains tended to be weakly reactive.
Klebsiella
strains were divided equally between nonreactive and weakly reactive. In practice, this test was also of great value in discerning nonpigmented
Serratia
cultured from the hospital environment and in detecting mixed flora containing nonspreading
Proteus
.
Detection of
Chlamydia psittaci
by Immunofluorescence
Authors: Lewis Vester J. , Thacker W. Lanier , Cacciapuoti A. F.
Published: December 2020

A direct fluorescent-antibody (FA) test was developed to detect
Chlamydia psittaci
in dural impressions from specimen-inoculated mice. Technical procedures for the test were compared.
C. psittaci
was found in mice after infection as early by the FA technique as it was by cytochemical staining methods usually used. The lymphogranuloma venereum organism was also stained by conjugated antibody to
C. psittaci
. A distinctive advantage of the described FA test is that organisms are identified immunologically as members of the genus
Chlamydia
simultaneously with their detection.
Cellulolytic Activity of
Thermomonospora curvata
: Optimal Assay Conditions, Partial Purification, and Product of the Cellulase
Authors: Stutzenberger Fred J.
Published: December 2020

Thermomonospora curvata
produces cellulases active against both cotton fibers (designated C
1
activity) and carboxymethylcellulose (C
x
activity). In reaction systems employing optimal substrate concentration,
p
H, and temperature, hydrolysis rates (measured by the release of soluble reducing sugars) were initially linear and decreased on prolonged incubation, although only a small amount of substrate (1 to 2%) had been hydrolyzed. Persistence of this lower rate, even after addition of fresh enzyme (in the C
1
assay system), indicated alteration of cellulose susceptibility to hydrolysis rather than enzyme inactivation. Partial purification by (NH
4
)
2
SO
4
precipitation and exclusion chromatography resolved cellulase activity into two fractions. The sole product of purified cellulase activity on ground cotton fibers appears to be cellobiose.
Differentiation Between Herpes Simplex Virus Type 1 and Type 2 Strains by Immunoelectroosmophoresis
Authors: Jeansson Stig
Published: December 2020

A method has been elaborated to differentiate between herpes simplex type 1 and type 2 viruses by immunoelectroosmophoresis. With rabbit immune sera cross-absorbed with heterologous virus antigen, a distinct difference was shown between the two virus types. Herpes simplex type 1 virus tested against cross-absorbed type 1 antiserum gave two precipitin lines. Herpes simplex type 2 virus gave one precipitin line when tested against cross-absorbed homologous serum. When the viral antigens were tested against cross-absorbed heterologous immune sera, no or only very weak precipitin reactions were observed. The test is easy and rapid, requires relatively small quantities of antigen and antibody, and is suitable for typing of herpes simplex virus in diagnostic routine work.
Stomaching: a New Concept in Bacteriological Sample Preparation
Authors: Sharpe A. N. , Jackson A. K.
Published: December 2020

An entirely new mixing device, particularly suitable for preparing bacterial suspensions from foods, fabrics, swabs, and other fairly soft materials, has been developed. With this technique the sample and diluent are put into an inexpensive, sterile plastic bag which is vigorously pounded on its outer surfaces by paddles when placed inside the machine. The resulting compression and shearing forces effectively remove even deep-seated bacteria. After samples are taken for analysis the bag and its remaining contents are thrown away. Labor involved in cleaning and sterilizing reusable homogenizer cups or probes is eliminated, and the device is immediately ready for reuse. Running costs are thus drastically reduced, compared with conventional homogenizers. Additional advantages of this device, which is simple and inexpensive to manufacture, are low noise level, negligible temperature rise, and the small storage space required for bags.
Evaluation of a Microtiter Latex Agglutination Test for Histoplasmosis
Authors: Gerber Jay D. , Riley Richard E. , Jones Robert D.
Published: December 2020

Experiments were designed to evaluate a Microtiter latex agglutination (Micro-LA) test, as a serological aid in the diagnosis of histoplasmosis, and to compare this test with the conventional microtiter-complement fixation (CF) test for histoplasmosis. Sera tested were from cases of acute and chronic pulmonary and disseminated histoplasmosis, as well as from individuals not having histoplasmosis. Ninety-seven percent of the cases of acute pulmonary histoplasmosis had positive Micro-LA tests, whereas 91% had positive CF tests. Ninety-six percent of the patients having chronic pulmonary histoplasmosis showed positive Micro-LA tests and 91% had positive CF tests. In contrast, 64% of the cases of disseminated histoplasmosis had positive Micro-LA tests, whereas 82% had positive CF tests. None of these differences was statistically significant. Although there were no significant differences in complement fixing and agglutinating antibody cross-reactivity with
Blastomyces
antigens, more patients demonstrated CF titers than Micro-LA titers. Sera from patients with acute and chronic histoplasmosis showed higher Micro-LA titers than CF titers, whereas sera from cases of disseminated histoplasmosis showed higher CF titers. Histoplasmin skin testing has less of a boosting effect on agglutinating antibodies than on CF antibodies to histoplasmin. Anticomplementary sera can be used in the Micro-LA test. This test is simple to perform, and results can be obtained in 2 to 4 hr.
Comparison of the Reliability and Sensitivity of Three Serological Procedures in Detecting Antibody to
Yersinia pestis (Pasteurella pestis)
Authors: Marshall John D. , Mangiafico Joseph A. , Cavanaugh Dan C.
Published: December 2020

Three serological procedures, the agar-gel precipitin inhibition, the complement fixation, and the indirect hemagglutination tests, were used to detect and measure antibody to
Yersinia pestis
in the sera from 383 individuals. Although all three tests were useful in detecting plague antibody, the most reliable and sensitive test procedure was indirect hemagglutination.
Utilization of Collagenous By-Products from the Meat Packing Industry: Production of Single-Cell Protein by the Continuous Cultivation of
Bacillus megaterium
Authors: Bough Wayne A. , Brown W. L. , Porsche Jules D. , Doty D. M.
Published: December 2020

The conditions for continuous cultivation of
Bacillus megaterium
on a collagen-derived substrate (SP-100) were determined. The optimum conditions of temperature,
p
H, and dilution rate were 34 C,
p
H 7.0, and 0.25/hr, respectively. Increasing the substrate concentration in plain tap water resulted in proportional increases in the productivity of cell mass from 0.6 g per liter per hr at 1% substrate to 1.8 g per liter per hr at 10% substrate; however, the protein content of the biomass decreased from 60 to 36%, and the protein yield decreased from 91 to 50% at substrate concentrations of 1 and 10%, respectively. These effects (decreases) were reversed up to 7.5% substrate by mineral supplementation of the medium. The productivity of biomass increased from 0.6 to 1.9 per liter per hr; the protein content of the biomass, from 43 to 54%; and the protein yield, from 60 to 93%, respectively, as the substrate concentration (with mineral supplementation of the medium) was increased from 1 to 7.5%. Spent medium could be refortified and recycled as often as five times. The amino acids in the substrate protein appeared to be utilized for growth and metabolism more or less uniformly. Analysis of the
B. megaterium
biomass indicated considerable enrichment of the essential amino acids and reduction of proline, glycine, and hydroxyproline as compared to the collagen-derived substrate. The Protein Efficiency Ratios obtained on the collagen-derived substrate (SP-100) and on the
B. megaterium
biomass, expressed as percentages of the casein reference protein, were 14 and 74%, respectively. Thus, considerable improvement in nutritional value was effected by bacterial conversion of the collagen-derived substrate into single-cell protein.
Repair of Injury Induced by Freezing
Escherichia coli
as Influenced by Recovery Medium
Authors: Ray B. , Speck M. L.
Published: December 2020

Freezing an aqueous suspension of
Escherichia coli
NCSM at -78 C for 10 min, followed by thawing in water at 8 C for 30 min, resulted in the death of approximately 50% of the cells, as determined by their inability to form colonies on Trypticase soy agar containing 0.3% yeast extract (TSYA). Among the survivors, more than 90% of the cells were injured, as they failed to form colonies on TSYA containing 0.1% deoxycholate. Microscope counts and optical density determinations at 600 nm suggested that death from freezing was not due to lysis of the cells. Death and the injury were accompanied by the loss of 260- and 280-nm absorbing materials from the intracellular pool. Injury was reversible as the injured cells repaired in many suitable media. The rate of repair was rapid and maximum in a complex nutrient medium such as Trypticase soy broth supplemented with yeast extract. However, inorganic phosphate, with or without MgSO
4
, was able to facilitate repair. Repair in phosphate was dependent on the
p
H, the temperature, and the concentration of phosphate.
Use of Polyelectrolytes and Electron Microscopy for Detection of Viruses from Stool
Authors: Chaudhary R. K. , Westwood J. C. N.
Published: December 2020

Insoluble polyelectrolytes (PE60) were used for the concentration of viruses from stool specimens, confirming the results of Wallis et al. (1969). Ten percent suspensions inoculated with poliovirus type 3 were used in these experiments. A small number of stool specimens from patients naturally infected with enteroviruses were also tested. Preferential adsorption of viruses to PE60 was maximum at a
p
H range of 4.5 to 6.0. The elution of the adsorbed viruses was optimal at
p
H 8.5. Other parameters were also investigated. Electron microscopy was used successfully to detect the eluted viruses.
Apparatus for Fixing, Staining, and Rinsing of Tissue Cultures for Fluorescent-Antibody Testing
Authors: Poole George M.
Published: December 2020

A staining tray and tray-housing container have been developed to facilitate fluorescent-antibody staining of tissue cultures on cover slips, which allows fixing, staining, and rinsing with a minimum of handling. Breakage and loss of cells were negligible.
Elimination of Repeated Clot Formation in Mouse Ascitic Fluid Containing Arbovirus Antibodies
Authors: Chiewsilp Dumrong , McCown Jack M.
Published: December 2020

Repeated clot formation in mouse ascitic fluids containing antiviral antibody was eliminated by acid precipitation of the fibrinogen.
Long-Term Preservation and Storage of Mycobacteria
Authors: Kim Thomas H. , Kubica George P.
Published: December 2020

Under contract with the National Institute of Allergy and Infectious Diseases, the Trudeau Mycobacterial Culture Collection has been greatly expanded to provide for the scientific community a collection of representative strains of mycobacteria of biomedical importance. Problems concerned with the preparation, bottling, and distribution of such organisms have been dealt with and are detailed in this paper. Examination of collected data revealed that the temperature of storage and not the suspending menstruum was more important for prolonged survival of mycobacteria stored at subzero temperatures. For optimum results, mycobacteria may be suspended either in Dubos Tween-albumin broth or in Middlebrook 7H-9 liquid medium supplemented with ADC enrichment (commercial sources used) and stored at −70 C. Either of these suspending fluids supplied a growth-supporting medium for cultures which must be shipped long distances, often without refrigeration. To avoid sublimation of suspending medium during prolonged storage at −70 C (a problem inherent in many screw-capped containers), we have chosen to use vaccine-stoppered serum bottles sealed with aluminum crimp caps. The methods described have provided suspensions with (i) excellent viability over prolonged periods of storage, (ii) stable metabolic activities, and (iii) highly reproducible inocula for animal experiments.
Salmonellae as an Index of Pollution of Surface Waters
Authors: Cherry William B. , Hanks John B. , Thomason Berenice M. , Murlin Alma M. , Biddle James W. , Croom John M.
Published: December 2020

Screening enrichments of surface water specimens by means of a polyvalent fluorescent antibody reagent for the salmonellae yielded approximately 60% more positive specimens than was obtained by cultural procedures. It is not known what fraction of the excess of fluorescent antibody-positive over culturally positive specimens represents staining of non-salmonellae or non-arizonae as opposed to the staining of non-cultivatable organisms of these two genera. Cotton gauze and rayon-polypropylene fiber swabs were equally sensitive for collecting salmonellae from the streams examined. Tetrathionate enrichment incubated at 41.5 C appeared to be superior to selenite-cystine for isolation of salmonellae from surface waters. Twenty-eight serotypes of
Salmonella
and two serotypes of
Arizona
were identified in the 121 positive specimens. In water rated moderately polluted, 65% of all specimens tested were positive; in minimally polluted waters, 38% were positive; and in unpolluted streams, 44% were positive.
Bacillus cereus
-Induced Fluid Accumulation in Rabbit Ileal Loops
Authors: Spira W. M. , Goepfert J. M.
Published: December 2020

The usefulness of the ligated rabbit ileal loop as an experimental model of
Bacillus cereus
food poisoning was investigated. Positive responses, as measured by fluid accumulation in the loop, were obtained from 19 of 22 strains of
B. cereus.
Four of six strains of
B. thuringiensis
also elicited fluid accumulation, but eight strains of other
Bacillus
spp. failed to evoke a response. The growth medium employed markedly affected the ability of a given strain of
B. cereus
to provoke a response. Brain heart infusion broth (BHI) (Difco) proved to be best for this purpose. Loop fluid-inducing activity was produced by exponentially growing cells and was present in cell-free culture filtrates and associated with washed vegetative cells. Intraluminal growth of
B. cereus
did not elicit fluid accumulation. Cultures grown at temperatures in the range of 18 C to 43 C were loop active. When BHI cultures of selected loop positive strains were injected intraluminally into the normal ileum of rabbits, they failed to elicit diarrhea.
Evaluation of Modified R-B System for Identification of Members of the Family
Enterobacteriaceae
Authors: McIlroy Gary T. , Yu Pauline K. W. , Martin William J. , Washington John A.
Published: December 2020

In a paired, double-blind study, the modified (“Beckford tube”) R-B system was compared with conventional bacteriological procedures for the identification of members of the family
Enterobacteriaceae
from clinical isolates and stock cultures. The tests in the R-B system yielding positive reactions comparable to those predicted by Ewing's taxonomic classification of
Enterobacteriaceae
were production of hydrogen sulfide and presence of lysine and ornithine decarboxylasè activities. The test reactions in the R-B system found to be comparable to those in the conventional method were fermentation of glucose, hydrogen sulfide production, and lysine and ornithine decarboxylase activities. The production of gas from glucose was positive in the R-B system more often than in the conventional method; however, the motility test and the production of indole were positive less often in the R-B system. Adequate preliminary identification of the
Enterobacteriaceae
with the R-B system is enhanced if Simmons' citrate and Christensen's urea tests are used concomitantly. These findings emphasize the manufacturer's instructions that, in interpretation of results, colonial morphology and biochemical reactions must be used concurrently to make an accurate identification.
Nitrite Burn in Fermented Sausage
Authors: Bacus J. N. , Deibel R. H.
Published: December 2020

A rare outbreak of anaerobic nitrite burn in fermented sausage afforded the isolation and characterization of the offending microorgansim which was identified as a
Staphylococcus
sp. Unlike most staphylococci, this organism reduces nitrite as well as nitrate.
Identification of a Germination System Involved in the Heat Injury of
Bacillus Subtilis
Spores
Authors: Busta F. F. , Adams D. M.
Published: December 2020

Bacillus subtilis
A spores were injured by exposure to heat treatments of 110 to 132 C. Injury was demonstrated by the inability to form colonies on fortified nutrient agar (FNA) unless the medium was supplemented with CaCl
2
and Na
2
dipicolinate (CNA). A preliminary heat treatment fully heat-activated the spores, was not lethal, and did not prevent injury by subsequent secondary heat treatment. Exposure of heat-activated spores to 122 C reduced germination in FNA. The primary germination agents in FNA were identified, and a defined germination medium of glucose, NaCl,
l
-alanine, and sodium phosphate (GNAP) was developed. Germination of heat-activated spores in GNAP was equivalent to germination in FNA. Injury measured by colony formation on FNA and CNA was correlated to injury measured by reduced germination in both FNA and GNAP. Inactivation of the FNA and GNAP germination systems by secondary treatment exhibited similar kinetics. Therefore, injury expressed as the inability to form colonies on FNA involved alteration of the GNAP germination system.
API System: a Multitube Micromethod for Identification of
Enterobacteriaceae
Authors: Smith P. B. , Tomfohrde K. M. , Rhoden D. L. , Balows A.
Published: December 2020

The API system for identification of
Enterobacteriaceae
was evaluated with 366 cultures. Overall accuracy of identification was 96.4%; of the 13 cultures misidentified, 7 were atypical strains.
Ultrastructural Alterations Induced by Moist Heat in
Bacillus cereus
Authors: Silva M. T. , Sousa J. C. F.
Published: December 2020

The ultrastructural alterations induced in vegetative, exponentially growing
Bacillus cereus
cells suspended in broth, by heating at 65 C for 2 and 15 min and 100 C for 5 min, were studied by electron microscopy of thin sections. The following alterations were observed: (i) change in the triple-layered profile of the membranes from the normal asymmetric to a symmetric geometry, appearance of fractures in the membranes, occurrence of prominent myelin-like systems of concentric membranes; (ii) disappearance of the ribosomes in most cells heated at 65 C and in all cells heated at 100 C; (iii) cytoplasmic precipitation resulting in the appearance of dense blocks of Pronase-sensitive material. The cell wall appears unaffected in most preparations. No signs of deoxyribonucleic acid damage are observed. These ultrastructural data are discussed in relation to the alterations in the chemistry and physiology of heated bacteria described in the literature.
Purification of Large Amounts of Murine Ribonucleic Acid Tumor Viruses Produced in Roller Bottle Cultures
Authors: Syrewicz James J. , Naso R. B. , Wang C. S. , Arlinghaus Ralph B.
Published: December 2020

Murine ribonucleic acid tumor viruses and C-type virus particles are produced in relatively large quantities in roller bottle cultures. The viruses present in large volumes of culture fluids can be purified by a simple two-step procedure involving polyethylene glycol precipitation and equilibrium centrifugation in sucrose density gradients.
Method for Staining and Preserving Agar Gel Diffusion Plates
Authors: Lumpkins Earl D.
Published: December 2020

An improved method for the preservation of agar gel precipitin lines has been developed.
Improved Cell Dispersal Method by Low-Temperature Incubation of Tissue in a Trypsin-Citrate Solution
Authors: van Wezel A. L. , van Hemert P. A. , Parisius W. , Cucakovich N. B. , Macmorine H. G.
Published: December 2020

Tissues soaked at low temperature in a trypsin-citrate solution, washed to remove enzymes, and disrupted by rapid mechanical vibrations gave yields of viable cells 1.6 to 5 times those from conventional procedures.
Death of
Lactobacillus bulgaricus
Resulting from Liquid Nitrogen Freezing
Authors: Smittle R. B. , Gilliland S. E. , Speck M. L.
Published: December 2020

Concentrated cell suspensions of
Lactobacillus bulgaricus
prepared from cells grown in semisynthetic media were frozen in liquid nitrogen. After storage for 24 hr, the cell suspensions were found to have decreased colony counts and acid-producing capacity in milk. The amount of loss varied among the different strains tested. The addition of known cryoprotective agents to cell suspensions of the most labile strain before freezing provided little or no protection to the cells. However, storage stability of all strains investigated was improved by supplementing the growth medium with Tween 80 (polyoxyethylene sorbitan monooleate). The concentration of Tween 80 necessary for maximal storage stability varied among strains.