bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid Determination by Light Scattering of Growth Parameters of
Mycoplasma laidlawii
in Liquid Media
Authors: Wolf Joseph P. , Marcus Leon
Published: December 2020

An impediment to progress in the study of the course of growth, the effects of medium components, antibiotics, etc., of
Mycoplasma
has been the cumbersome methods of growth measurement currently in use. Heretofore, it required the plating of numerous samples during growth, at least in triplicate, after appropriate dilution, followed by a delay of 2 to 3 days before the colonies developed so that counts could be made. We applied the technique of light scattering to measure the growth of
Mycoplasma laidlawii
in liquid culture continuously in a manner analogous to the use of absorbancy for bacteria. Scattered light measurements precisely paralleled data obtained by the tedious method of plate counts and were available immediately during the development of the culture. The lower limit of sensitivity with the system described is 10
5
Mycoplasma
per ml. The presence of serum in the medium lowers sensitivity somewhat. However, concentrations of serum up to 10% are easily tolerated. Higher serum content may require calibration curves. Thus the technique may be used with many pathogens, etc., that require serum to develop. One can easily and rapidly measure differences in growth rates as well as final cell yields during the course of growth, rather than 3 days later, after colonies have developed.
Enzymatic Reduction of Iron Oxide by Fungi
Authors: Ottow J. C. G. , Von Klopotek A.
Published: December 2020

The occurrence of the iron-reducing phenomenon among some common fungi was studied. Results indicated that (i) the reduction of ferric iron to the ferrous state by fungi seems to be restricted to nitrate reductase-inducible strains such as
Actinomucor repens, Alternaria tenuis, Fusarium oxysporum
, and
F. solani
and (ii) the amount of dissolved ferrous iron may be reduced progressively by increasing the amount of nitrate added to the medium. Compared with a complex medium (Sabouraud medium), less iron became reduced if NO
3
-
was the only nitrogen source (Czapek Dox medium). These data strongly support the view that ferric iron is acting as an hydrogen acceptor in respiration, competing with nitrate for electrons that are mediated by the enzyme nitrate reductase. The significance of this property from an ecological viewpoint is discussed.
Assay of the Antibiotic Activity of Serum
Authors: Traub Walter H.
Published: December 2020

One of the drawbacks of the “tube dilution” method for the assay of antibiotics in human serum has been illustrated by utilizing serum-sensitive and serum-resistant strains of
Escherichia coli
. In the case of serum-sensitive strains, it was found that fresh serum alone may account for the same degree of inhibition and thus yield minimal inhibitory concentrations identical to those obtained with serum combined with antibiotics, that is, “simulated” serum assay specimens. This fallacy of the method is discussed with regard to those instances in which laboratories were merely to utilize the patient's own coliform organism as the test organism, or with respect to the assay of, for example, polymyxins, in which inadvertently a R(ough) and therefore, serum-sensitive strain of
E. coli
were to be used as the indicator organism. It is recommended that serum-resistant laboratory strains of
Staphylococcus aureus
or
E. coli
of known antibiotic susceptibility be employed as the test organisms proper in order to circumvent the inherent bactericidal activity of serum.
In Vitro Studies of a New Semisynthetic Penicillin, 6-(D-α-Sulfoaminophenylacetamido)-Penicillanic Acid
Authors: Bodey Gerald P. , Stewart Dorothy
Published: December 2020

The activity of 6-(D-α-sulfoaminophenylacetamido)-penicillanic acid was determined against 357 clinical isolates of gram-negative bacilli by use of the tube-dilution technique. The majority of the isolates of
Pseudomonas
species were inhibited by 200 μg/ml or less of this antibiotic. Most of the isolates of
Escherichia coli
had a minimal inhibitory concentration of 50 μg/ml or less. Seventy-three per cent of the isolates of
P. mirabilis
, 40% of the isolates of
P. morganii
, and 45% of the isolates of
Enterobacter
species were inhibited by 12.5 μg/ml or less, whereas most of the isolates of
Klebsiella
species and
Serratia
species were resistant. The activity of this semisynthetic penicillin was affected by the size of the inoculum. The drug was bactericidal against all isolates of
E. coli
and
Proteus
species that were sensitive to it, but it was bactericidal against only 32% of the sensitive isolates of
Pseudomonas
species.
Coconut as a Medium for the Experimental Production of Aflatoxin
Authors: Arseculeratne S. N. , De Silva L. M. , Wijesundera S. , Bandunatha C. H. S. R.
Published: December 2020

Fresh, grated coconut has been found to be an excellent medium for aflatoxin production by
Aspergillus flavus
. Under optimal conditions, yields of 8 mg of total aflatoxin per g of substrate were obtained. Continuous agitation of the growth medium under moist conditions at 24 C produced highest yields. Aflatoxin was assayed both biologically and chromatographically. The aflatoxin content of cultures varied biphasically with the duration of incubation. It is suggested that this pattern could result from the sequential operation of factors promoting aflatoxin formation on the one hand and a detoxifying mechanism on the other.
Characterization of
Micrococcaceae
Isolated from Clinical Sources
Authors: Person Donald A. , Yu Pauline K. W. , Washington John A.
Published: December 2020

The characterization of 556
Micrococcaceae
isolates from various clinical sources has been presented. The incidence of coagulase-negative mannitol-positive staphylococci was 3.2% and that of coagulase-positive mannitol-negative staphylococci was 1.6%. There appears to be insufficient justification for the routine reporting of staphylococcal variants from a general bacteriology laboratory, and biotyping should be reserved for special circumstances.
Influence of Statolon on Resistance of Mice to Influenza
Authors: Pindak Frank F. , Schmidt Jerome P. , Kendrick Jerry Z.
Published: December 2020

Various interferon inducers are known to elicit protection against lethal or infecting doses of certain viral agents. Because of the relatively high morbidity rate of influenza and its seasonal occurrence, we wished to determine whether statolon-induced interferon might be effective in controlling this disease. Mice were treated intraperitoneally with statolon and challenged with influenza A
2
virus by the intranasal route. Although interferon was present in the serum at the time of virus administration, no change in mortality rate was observed. There was, however, a significant increase in the mean survival time of treated animals. Similar results were obtained when Newcastle disease virus was used as the interferon inducer. To determine the effect of the route of challenge, other mice were treated with statolon or Newcastle disease virus and inoculated with mengovirus by the intranasal or intraperitoneal route. The results demonstrated that the treated mice were protected to similar degree against challenge by either route. It is suggested that the relative ineffectiveness of interferon in protecting mice against influenza is due to an intrinsic characteristic of the virus itself rather than the type of interferon induced or the route of virus challenge.
Four-Hour Urease Test for Distinguishing Between
Klebsiella
and
Enterobacter
Authors: Barry A. L. , Bernsohn K. L. , Thrupp L. D.
Published: December 2020

Infections with
Klebsiella
and
Enterobacter
have increased among hospitalized patients. To study such infections, relatively simple but precise methods are needed for clinical laboratories to identify the two genera accurately. Moreover, a rapid identification is essential for assisting with the therapy of the patients. For this purpose, a new 4-hr urease test was developed so that colonies could be tested directly from blood-agar plates which have been inoculated with clinical material and allowed to incubate overnight. This 4-hr test was positive with 98.5% of 202
Klebsiella
species and negative with 80
Enterobacter
species. As a single criterion for distinguishing between the two major genera, the new 4-hr urease test was just as accurate as a motility test (99% of the 282 isolates were accurately identified with either). The 4-hr urease test represents a simple, rapid, and reliable technique which is ideally suited for use in clinical microbiology laboratories.
Antibacterial Activity of 2′-Esters of Erythromycin
Authors: Tardrew P. L. , Mao J. C. H. , Kenney D.
Published: December 2020

The effect of esterification at the 2′-position of desosamine on the antibacterial activity of erythromycin was investigated by determining the bacteriostatic and bactericidal activities of erythromycin and a number of its 2′-esters on
S. aureus
and relating these activities to the hydrolysis rates of the esters. These studies, together with comparison of the inhibition of protein synthesis in a cell-free system isolated from
S. aureus
, lead to the conclusion that 2′-esters of erythromycin are inactive until hydrolyzed. Loss of activity appears to result from inability of erythromycin esters to bind to bacterial ribosomes and thus inhibit synthesis of protein.
Control of
Byssochlamys
and Related Heat-resistant Fungi in Grape Products
Authors: King A. Douglas , Michener H. David , Ito Keith A.
Published: December 2020

Heat-resistant strains of
Byssochlamys fulva, B. nivea
, and other heat-resistant fungi were isolated from vineyard soil, grapes, grape-processing lines, and waste pomace. They are known to remain in grape juice occasionally and to grow in grape juice products. Ascospores of these fungi have a D value (decimal reduction time) of about 10 min at 190 F (88 C), but in the presence of 90 μliters of SO
2
per liter (normally added to the juice) the D value was cut in half. Filtration through a commercial diatomaceous filter aid (also a common processing step) entrapped all but about 0.001% of experimentally added spores. Thus, heat in the presence of SO
2
and filtration together can reduce the population of these spores by several orders of magnitude. Growth was also prevented by benzoate or sorbate in low concentrations. Oxygen must be reduced to extremely low levels before lack of oxygen limits growth.
Time, Cost, and Efficacy Study of Identifying Group A Streptococci with Commercially Available Reagents
Authors: Chitwood Lawrence A. , Jennings Myra B. , Riley Harris D.
Published: December 2020

During the 12-month period primary throat, wound, and skin cultures, tentatively identified as B streptococci, were submitted by 10 different clinical laboratories for evaluation. A total of 692 beta-hemolytic streptococci were isolated from cultures submitted and examined in parallel by the fluorescent-antibody, precipitin, and bacitracin techniques. An evaluation of the specificity and sensitivity in conjunction with basic and personnel costs was determined for each method. The standard Lancefield precipitin method was established as the standard by which the bacitracin and flourescent antibody techniques were compared. With some variation depending on the commerical source of the disc, approximately 7% of the strains examined produced false reactions with the bacitracin disc. False-negative reactions were rarely noted by the group A fluorescent antibody technique (0.5%), but an appreciable number of other Lancefield groups (B, C, and G) were nonreactive with homologous conjugates.
Micro Test for Streptococcal Anti-deoxyribonuclease B
Authors: Klein George C. , Baker Carolyn N. , Addison Betty V. , Moody Max D.
Published: December 2020

A methyl green decolorization micro test for the determination of streptococcal anti-deoxyribonuclease B titers in serum is described. The micro test was compared with an alcohol precipitation macro test on 112 human sera. The anti-deoxyribonuclease B titers agreed within one dilution step for 85.7% of the 112 sera examined by both techniques. Both tests were about equal in the detection of titers above the upper limits of normal. The micro test requires smaller amounts of reagents and fewer man-hours to perform than the macro test. This translates into lower cost per test and more tests per man-hour.
Comparative Sensitivity of Tissue Cultures to Rubella Virus: Use of Guinea Pig Cells for Virus Titration
Authors: Horta-Barbosa L. , Warren Joel
Published: December 2020

A series of 19 different primary and serial tissue cultures were investigated for their sensitivity to virulent or attenuated rubella virus (RV). Primary guinea pig tissues, a serial passage of baby hamster kidney, and primary human amnion were comparable to African green monkey kidney tissue cultures in their sensitivity. In general, primary human tissues were relatively insusceptible to the Gilchrist strain of RV. RV interfered with the growth of vesicular stomatitis virus. Based on this finding, it was possible to develop an assay method in guinea pig tissue cultures by using VSV as the challenge virus. This system appeared to be comparable in sensitivity to the use of primary monkey kidney tissue cultures for the detection of small amounts of RV and offers the advantages of economy, rapidity, and safety.
Agar Plate Method for Detecting Microorganisms Which Produce Equilin and Other Estrogens from Various Steroids
Authors: Vezina Claude , Singh Kartar , Sehgal S. N.
Published: December 2020

The intense red color produced by a reagent specific for ξ
7
-estrogens is used to directly detect microorganisms which produce these estrogens from various steroids.
Reversal by Citrate of the Iodoacetate and Fluoride Inhibition of Glutamic Acid Production by
Corynebacterium glutamicum
Authors: Birnbaum Jerome , Demain Arnold L.
Published: December 2020

Citrate reversal of iodoacetate inhibition of glutamate synthesis is nonmetabolic. Reversal of fluoride inhibition is metabolic, occurring only at low Mg concentrations.
Detection of Lymphocytic Choriomeningitis Virus Antibody in Murine Sera by Immunofluorescence
Authors: Lewis Vester , Clayton Diane
Published: December 2020

An immunofluorescence technique developed for detection of antibody in murine sera to lymphocyitc choriomeningitis virus is described.
Negative-Pressure Isolator for Work with Hazardous Infectious Agents in Monkeys
Authors: Tauraso Nicola M. , Norris George F. , Sorg Thomas J. , Cook Reginald O. , Myers Murrel L. , Trimmer Roy
Published: December 2020

The development, fabrication, and use of a negative-pressure isolator for work with hazardous infectious agents in monkeys or other larger animals are described.
Fermentation Patterns of Poorly Fermenting Cabbage Hybrids
Authors: Stamer J. R. , Dickson M. H. , Bourke J. B. , Stoyla B. O.
Published: December 2020

Thirteen varieties of cabbage, including five commonly used commercial varieties and eight newly developed hybrids, were analyzed for their ability to undergo lactic acid fermentations. The rates of fermentation, total quantities of acids produced, and chemical analyses indicate that 11 of the 13 selections could support adequate fermentation at any of the three stages of maturation. However, two varieties G27 × G51 (105) and G60 × W-1 (106), harvested during the earlier phases of the 1967 and 1968 growing seasons, failed to undergo proper fermentations and consistently resulted in producing putrid products. These hybrids when harvested at the late stage of maturation were capable of producing total titratable acidities comparable to the acceptable varieties. However the resulting sauerkrauts were judged to be of poor quality. The inability of these varieties to support adequate fermentations may be due to growth inhibitory substances or the lack of inherent maturation-dependent growth factor(s) essential for the growth of lactic acid bacteria.
Effects of Topical Anesthetics on
Pullularia pullulans
and
Debaryomyces hansenii
Authors: Merdinger Emanuel , Guthmann Walter S. , Mangine Francis W.
Published: December 2020

The inhibitory effects of three topical anesthetics of various concentrations on the growth of
Pullularia pullulans, Debaryomyces hansenii,
and on pigment production by
P. pullulans
were investigated. The topical anesthetics were benoxinate hydrochloride, proparacaine hydrochloride, and tetracaine hydrochloride. In decreasing order, the inhibiting effects of the drugs on growth were benoxinate, tetracaine, and proparacaine for
P. pullulans,
and tetracaine, benoxinate, and proparacaine for
D. hansenii.
The pigment formation in
P. pullulans
was inhibited by the three drugs.
Comparative Study of Responses to Neomycins B and C by Microbiological and Gas-Liquid Chromatographic Assay Methods
Authors: Tsuji Kiyoshi , Robertson John H. , Baas Ruth , McInnis D. J.
Published: December 2020

The relative responses of neomycins B and C have been determined by a microbiological agar-diffusion method, a turbidimetric method, and by a recently developed gas-liquid-chromatographic (GLC) method capable of separating the neomycin isomers. The ratios of response of neomycin C to neomycin B by the individual methods were as follows: agar-diffusion method, 1:3; turbidimetric method, 1:2.5; and GLC method, 1:1. When neomycin C is assumed to have 35% biological activity of neomycin B, the calculated drug contents of neomycin sulfate powders obtained by the GLC method correlated well with values obtained by the microbiological agar-diffusion assay method.
Loss of Rubella Antibody from Immune Globulin Treated with Kaolin
Authors: Cabasso V. J. , Louie R. E. , Hok K. A. , Robinson C. T. , Davis P. C. , Miner R. C.
Published: December 2020

Sera and immune globulin (IG) preparations are customarily treated with kaolin before titration of their rubella hemagglutination-inhibiting (HI) antibody in order to rid them of nonspecific inhibitors of hemagglutination. The treatment was shown in this investigation to have no adverse effect on the antibody level of the sera but was found to remove considerable amounts of gamma-globulin from IG preparations. Evidence of this removal was obtained by serological tests, by spectrophotometric determination of protein concentration and by disc electrophoresis. In contrast to kaolin, heparin-manganese chloride (MnCl
2
) treatment of IG preparations had essentially no effect on the level of antibody globulin by all the criteria used. Heparin-MnCl
2
-treated IG lots were in these respects similar, if not identical, to their untreated counterparts. Since nonspecific inhibitors associated with the β-lipoprotein fraction of serum are removed by the method employed to fractionate the IG samples, it seems unnecessary to treat the latter in any way for the HI test. No difficulty was encountered in this investigation with several untreated IG lots.

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Comparative Pathogenicity of
Actinomyces naeslundii
and
Actinomyces israelii
Authors: Coleman R. Marie , Georg Lucille K.
Published: December 2020

Typical actinomycosis has been produced in mice following single intraperitoneal injections of saline suspensions of
Actinomyces israelii
and
A. naeslundii. A. israelii
produced infections in 95.8% of the animals inoculated.
A. naeslundii,
generally considered to be a saprophytic organism, produced lesions in 89.7% of the inoculated animals. The finding that
A. naeslundii
produced lesions in mice similar to those produced by
A. israelii
suggests that
A. naeslundii
has similar pathogenic potential for man. The isolation of
A. naeslundii
from suppurative lesions of man also supports this conclusion.

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Preparation of La Crosse Virus Hemagglutinating Antigen in BHK-21 Suspension Cell Cultures
Authors: Chappell W. Adrian , Halonen Pekka E. , Toole Roberta F. , Calisher Charles H. , Chester Leo
Published: December 2020

Hemagglutinating and complement-fixing antigens of La Crosse virus (California arbovirus group) were produced in serum-free suspension cultures of BHK-21/13S cells. The appearance and production of these antigens were correlated with the titer of infectious virus. No significant differences in antigen titers were produced by varying virus dose 10-fold. Hemagglutinin appeared 6 to 8 hr after inoculation and reached peak titer in 14 to 22 hr. Both β-propiolactone and Tween 80-ether treatment inactivated infectious virus in the antigens. Unlyophilized antigen was stable at -60, 5 and 24 C for at least 117 days but not for 1 year. Lyophilized antigen was stable for at least a year, however, at -20 and 5 C. Cell culture-produced antigen was more sensitive than brain-produced antigen in detecting hemagglutination inhibition antibody in human sera.
Enzymes Produced by a
Pseudomonas
Species Which Inactivate Inhibitors of Certain Viral Hemagglutinins. I. Identification and Purification of a Proteinase and Phospholipase C
Authors: Schmidt Nathalie J. , Gee Pinkie S. , Dennis Juanita , Lennette Edwin H.
Published: December 2020

Filtrates from cultures of a psychrophilic
Pseudomonas
species, which inactivate serum inhibitors of certain viral hemagglutinins, were shown to contain both lecithinase (phospholipase C) and a proteolytic enzyme with elastase activity. The bacterium was cultivated under conditions favoring production of the respective enzymes, and the enzymes were purified by ammonium sulfate precipitation followed by column chromatography or by gel filtration. The elastase was obtained in crystalline form and was recrystallized. It has properties similar to those of a number of other bacterial elastases but is more heat-labile than most. Although a high degree of purification was achieved for the lecithinase, as evidenced by an increase in specific activity, it was not obtained in crystalline form. Partially purified preparations of the lecithinase had extremely high activity compared to that of commercial preparations of phospholipase C from
Clostridium welchii
.

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Chemotherapeutic Activity of Bluensomycin
Authors: Ray Brenda J. , Pittillo Robert F.
Published: December 2020

Bluensomycin inhibited various species of proteus in vitro at low concentrations. A lethal proteus infection in mice was cured by bluensomycin.
Electrically Heated Cuvette Chamber for Deoxyribonucleic Acid Melting Point Determinations
Authors: Levin R. E.
Published: December 2020

An electrically heated cuvette chamber has been constructed and found to yield a deoxyribonucleic acid melting point of 91.5 C for
Escherichia coli
B, as previously reported.

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Site of Action of Nitrofurantoin in Experimental Urinary Tract Infection
Authors: Rocha Heonir , Teles Edson Da Silva , Barros Milton
Published: December 2020

The effectiveness of nitrofurantoin in suppressing bacterial growth in the urinary tract was evaluated by using two different experimental models. Pyelonephritis was produced in rats by direct inoculation of 10
4
Escherichia coli
in the medulla of left kidney. Ascending urinary tract infection was induced by inoculation into the urinary bladder of 10
7
Proteus mirabilis
, after a partial cystectomy. Nitrofurantoin was shown to be effective in suppressing bladder bacteriuria, in preventing ascending pyelonephritis, and also in preventing bacterial multiplication in kidney tissue following direct inoculation.
Production of Tumor-Inhibitory L-Asparaginase by Submerged Growth of
Serratia marcescens
Authors: Heinemann Bernard , Howard Alma J.
Published: December 2020

Production of a tumor-inhibitory asparaginase by submerged fermentation with
Serratia marcescens
ATCC 60 was studied to ascertain optimal nutritional conditions for large-scale production leading to enzyme purification studies. Five strains of
S. marcescens
were screened in shake-flask studies and were found to produce 0.8 to 3.7 IU/ml 48 hr after inoculation. The requirements for asparaginase production with
S. marcescens
ATCC 60, the high producing strain, included the following: 4% autolyzed yeast extract medium (initial
p
H 5.0), an incubation temperature of 26 C, and limited aeration for a zero level of dissolved oxygen during the fermentation. Addition of various carbohydrates to the fermentation medium did not enhance yields. The peak cell population in the fermentation medium and the maximal asparaginase yields occurred simultaneously. Highest enzyme yields were found when the
p
H of the fermentation cycle rose to approximately 8.5. Yields of 4 IU of asparaginase/ml of cell suspension have been obtained consistently in 40 to 42 hr from 10-liter volumes (500 ml/4-liter bottle) produced on a reciprocating shaker. Scale-up to a 60-liter fermentor yielded 3.1 IU/ml in 35 hr.
Reaction of Airborne
Rhizobium meliloti
to Some Environmental Factors
Authors: Won William D. , Ross Harold
Published: December 2020

Survival of
Rhizobium meliloti
102F5 in aerosols at 20 C was maximal at high relative humidity (RH) and minimal at low RH. Relatively high concentrations of NO
2
, SO
2
, or formaldehyde were needed to significantly reduce viability of
R. meliloti
in aerosols at 50% RH. Except for the reduction in activity of formaldehyde by SO
2
, there was no additive or antagonistic effect of mixing pollutants. High environmental RH enhanced bactericidal activity of NO
2
and SO
2
. High RH minimized and low RH accentuated the biological effect of ultraviolet light of 300 to 400 nm wavelength.
Characterization of Ornithine Decarboxylase-Positive, Nonmotile Strains of the
Klebsiella-Enterobacter
Group
Authors: Matsen John M. , Blazevic Donna J.
Published: December 2020

Thirty-seven strains of ornithine decarboxylase-positive, nonmotile
Klebsiella-Enterobacter
organisms isolated from 36 patients were studied by biochemical and serological testing. Five strains gave biochemical reactions which conformed closely to those of
Escherichia coli
; three strains gave positive Quellung reactions to specific
Klebsiella
antisera. (Two of these were thought to be
Enterobacter
in spite of this typing reaction.) The remaining 29 strains were classified as
Enterobacter
. These results demonstrate the necessity of doing both an ornithine decarboxylase test and a motility test to differentiate
Klebsiella
from
Enterobacter
. Had only a motility test been done, they all would have been called
Klebsiella
.
Survey of Some
Actinomycetales
for α-Galactosidase Activity
Authors: Lyons A. J. , Pridham T. G. , Hesseltine C. W.
Published: December 2020

The enzyme α-galactosidase offers potential to (i) eliminate possibly the flatus-inducing factor(s) in edible beans, (ii) eliminate raffinose during beet-sugar processing, and (iii) determine raffinose analytically. Accordingly, 20 genera of the order
Actinomycetales
Buchanan 1917 were tested for evidence of α-galactosidase activity. Test filtrates were prepared with a medium containing D-galactose and soybean meal. Enzyme activity was demonstrated through cellulose thin-layer chromatography. Of 123 strains tested, 28 produced extracellular α-galactosidase. Almost all were streptomycetes. Members of the genera
Actinoplanes
Couch 1950,
Micromonospora
ϕOrskov 1923, and
Promicromonospora
Krasil'nikov et al. 1961 also exhibited α-galactosidase activity. Additional tests led to the selection of five strains whose filtrates degraded melibiose, raffinose, and stachyose but not lactose and sucrose. Tests also were made with several soybean preparations.
Simple Method for Rapid Determination of Antibiotic Blood Levels
Authors: Schneierson S. Stanley , Boyle Gerald L.
Published: December 2020

A simple method for the rapid determination of antibiotic blood levels is described. Results are readily obtainable within 4 to 6 hr. The reported procedure is based upon determination of the highest dilution of a patient's serum capable of inhibiting dextrose fermentation by a standardized inoculum of a staphylococcus strain or of an
Escherichia coli
strain, when colymycin or polymyxin are involved, as compared to previously determined endpoints in this regard of defined concentrations of the different antibiotics dissolved in normal human serum. Excellent correlation was observed with 36 serum specimens that contained different antimicrobial agents in varied concentrations when simultaneously assayed by the standard method and the subject procedure of this report.
Immunofluorescent Staining of
Salmonella
Species with Flagellar Sera
Authors: Goepfert J. M. , Hicks Ruthann
Published: December 2020

Salmonellae stained with flagellar sera by either the direct or indirect fluorescent-antibody technique fluoresced at the cell surface. Investigations showed that fimbriae, flagellar material, and capsule antigens were not the participating antigens in this reaction. Cell surface staining was inhibited by mannose but was unaffected by glucose, galactose, lactose, maltose, and sucrose. Specific absorption of the flagellar sera by intact cells and purified somatic antigen showed that O antigens were the site of the surface staining. The advantages of using flagellar sera in fluorescent-antibody screening of materials for the presence of salmonellae are discussed.
Biosynthesis of Ochratoxin A
Authors: Searcy J. W. , Davis N. D. , Diener U. L.
Published: December 2020

Biosynthesis of ochratoxin A by
Aspergillus ochraceus
Wilh. was investigated by radiolabeling experiments in which phenylalanine-
1
-
14
C
and sodium acetate-
2
-
14
C
were supplied to the fungus in sucrose-yeast extract medium. Results showed that phenylalanine was incorporated unaltered into the phenylalanine moiety of ochratoxin A, whereas the isocoumarin moiety of ochratoxin A was mostly derived via acetate condensation.
Some Properties of the Beta-Lactamase Genes in
Staphylococcus epidermidis
Authors: Baldwin Jack N. , Strickland Robert H. , Cox Marilyn F.
Published: December 2020

Eighty-three per cent of 200 different freshly isolated cultures of
Staphylococcus epidermidis
produced beta lactamase. Growth in the presence of acridine orange or ethidium bromide or growth at 44 C resulted in a high frequency of loss of the beta lactamase genes in some strains of
S. epidermidis
. The relationship between beta-lactamase production and resistance to mercuric, cadmium and arsenate ions differed from that observed in
Staphylococcus aureus
. It is postulated that the genes for beta lactamase in certain strains of
S. epidermidis
are on a plasmid.
Prophylactic Effects of γ-Aminobutyrylhistidine (Homocarnosine) on Experimental Staphylococcal Infections in Mice
Authors: Mukkada Antony J. , Nutini Leo G. , Cook Elton S.
Published: December 2020

Prophylactic administration of the dipeptide homocarnosine induced a high degree of resistance to staphylococcal infections in Swiss albino mice. It expressed its antistaphylococcal properties 1 hr after administration, and this protection lasted for at least 1 month. Although 5 mg per animal (approximately 200 to 250 mg/kg) was routinely used in our studies, experiments showed that comparable results could be obtained with 1.5 mg per animal. Rechallenge experiments indicated that an active infection by itself may confer immunity up to 4 weeks, but an infection after treatment with homocarnosine gave complete immunity to reinfection for at least 2 months. Studies in vitro showed that homocarnosine had no effect on the growth or certain other characteristics (ability to ferment mannitol, liquefy gelatin, and to produce coagulase, deoxyribonuclease, and pigment) of
S. aureus
. It appears that resistance induced by this peptide is an indirect effect mediated by some nonimmunological host reaction. The possible involvement of homocarnosine, among other compounds, in the protective action of deproteinized beef extract against staphylococcal infections is suggested.
Utilization of Electron Spin Resonance Spectroscopy for Observation of In Vivo Response to Fungicides
Authors: Rowlands John R. , Gause E. M.
Published: December 2020

Electron spin resonance studies of the in vivo response to fungicides (chloranil and thiram) by
Aspergillus niger
of different ages are described. The spores possessed a natural free radical signal which grew rapidly upon application of chloranil. Thiram, on the other hand, produced weak changes in the free radical region but easily detectable changes at lower fields, indicating involvement of copper and iron. In addition, flow experiments are described in which the production and decay of the chloranil semiquinone radical produced in the reaction of solutions of chloranil with extracts of bakers' yeast were monitored, both in the absence and in the presence of several buffers and respiratory chain inhibitors.
Isolation of Salmonellae and Shigellae from an Artificial Mixture of Fecal Bacteria
Authors: Isenberg Henry D. , Kominos S. , Siegel Marie
Published: December 2020

Numerous selective media, available commercially, act by suppressing “normal” bacterial inhabitants of the intestine while permitting the growth of so-called pathogenic representatives of the family
Enterobacteriaceae
. This investigation attempts to evaluate the action of
Salmonella-Shigella
(SS) agar, xylose lysine desoxycholate (XLD) agar, and hektoen enteric (HE) agar. Salmonellae and shigellae, isolated from clinical material, were mixed in various ratios with escherichiae,
Klebsiella-Enterobacter-Serratia
group bacteria, and members of the tribe
Proteeae
, also of clinical origin. Several of the mixtures were plated in multiple dilutions on the three media. Stools in preservative were also used for evaluation of the media after the addition of definite numbers of the pathogenic bacteria. Results indicate that SS agar suppresses the shigellae along with the autochthonous members of
Enterobacteriaceae
. XLD and HE agars readily permit the recovery of shigellae as well as salmonellae. This recovery is not obscured by the higher yield of other species obtained with these media.
Antiviral and Antitumor Antibiotics. XX. Effects of Rotenone, Deguelin, and Related Compounds on Animal and Plant Viruses
Authors: Takatsuki Akira , Nakatani Nobuji , Morimoto Makoto , Tamura Gakuzo , Matsui Masanao , Arima Kei , Yamaguchi Isamu , Misato Tomomasa
Published: December 2020

Rotenoids and related compounds were investigated for their effects on animal and plant viruses. Of 35 compounds examined, rotenone, rotenone norketone, acetylrotenone, acetylrotenone norketone, deguelin, deguelic acid, dehydrodeguelin, and isotubanol norketone, all used at low concentrations, suppressed the growth of Newcastle disease and herpes simplex viruses as determined by the agar diffusion, plaque inhibition method. Most of the compounds likewise decreased the number of necrotic spots on tobacco mosaic virus-infected leaf discs. Only derrisic acid completely inhibited the local lesion formation at subphytotoxic concentrations. Correlation of antiviral activity with respiratory inhibition of these compounds is discussed.
Quantitative Antibiotic Sensitivities of Ruminal Bacteria
Authors: Wang Chia-Li , Baldwin Beverly B. , Fulghum Robert S. , Williams Phletus P.
Published: December 2020

Fifteen species of ruminal bacteria were tested against 10 antibiotics in concentrations ranging from 0.1 to 200 μg/ml in an anaerobic tube dilution system.
Effect of Gravity on the Colonial Morphology of Staphylococci in Soft Agar
Authors: Wilkins Judd R. , Hatten Mary B. , Salmirs Seymour
Published: December 2020

After horizontal rotation on a clinostat at 1 rev/min, subsurface colonies of staphylococci in soft agar were compact and spherical; nonrotated colonies were diffuse and elongated.
Salmonella
Survey of Plant Foods Used in and Around the Home
Authors: Mittermeyer Frank C. , Foltz V. D.
Published: December 2020

Nine of 100 plant food samples investigated yielded salmonellae. A brilliant green tetrathionate-brilliant green agar combination gave the most salmonellae recoveries.
Pitfalls in Identification of Methicillin-Resistant
Staphylococcus aureus
Authors: Marcoux J. Andŕe , Washington John A.
Published: December 2020

Media and techniques for in vitro testing with respect to screening for methicillin-resistant
Staphylococcus aureus
are discussed.
Salmonella
in Wastes Produced at Commercial Poultry Farms
Authors: Kraft D. J. , Olechowski-Gerhardt Carolyn , Berkowitz J. , Finstein M. S.
Published: December 2020

Composite samples of freshly voided excreta from 91 poultry houses were tested qualitatively for
Salmonella
; 26 (29%) were positive. The houses were located on 36 farms, 18 of which (50%) yielded one or more positive samples. In a separate, quantitative study,
Salmonella
densities ranged from less than 1 to over 34,000 per g of excreta (dry weight). High densities were noted in waste from cage houses, but not in waste from floor houses (litter or wire floors).
Salmonella
-shedding chickens were located in only one small area of the row of cages examined in detail. A total of 15
Salmonella
serotypes were identified during the study.
Accelerated Immunofluorescence Procedure for the Detection of
Salmonella
in Foods and Animal By-Products
Authors: Fantasia Leonard D.
Published: December 2020

An accelerated, direct immunofluorescent-antibody procedure was developed for the detection of
Salmonella
in food products. This method includes pre-enrichment and selective enrichment but eliminates many of the washing and smear treatments present in existing methods. Commercially available fluorescein-conjugated somatic antiserum was used in comparing this method with conventional culture, biochemical, and serological procedures. The 894 samples tested represented 39 different products. The fluorescent-antibody procedure detected
Salmonella
in 216 test samples as compared to 205 positives recovered by using the standard culture procedures. In no instance did the fluorescent-antibody procedure fail to detect a
Salmonella
positive which had been detected by the standard procedure. With a three-tube, most-probable-number procedure, the fluorescent-antibody method was able to detect
Salmonella
at a level of 0.036 organism per g. In addition to being a more rapid method for the detection of
Salmonella
, it has proven to be comparable to conventional culture procedures.
Aflatoxin Production in Meats. I. Stored Meats
Authors: Bullerman Lloyd B. , Hartman Paul A. , Ayres John C.
Published: December 2020

Aflatoxins were produced on fresh beef (in which bacterial spoilage was delayed with antibiotics), ham, and bacon inoculated with toxinogenic fungi and stored at 15, 20 and 30 C. Meats stored at 10 C were spoiled by bacteria and yeast before detectable levels of aflatoxins were produced. High levels of aflatoxins were formed in meats stored at 20 C; one sample supported the production of 630 μg of aflatoxins per g of meat, the major portion (580 μg) of which was aflatoxin G
1
. Meats stored below 30 C developed higher levels of aflatoxin G
1
than B
1
, but at 30 C
Aspergillus flavus
produced equal amounts of B
1
and G
1
, whereas
A. parasiticus
continued to produce more G
1
than B
1
.
Aflatoxin Production in Meats. II. Aged Dry Salamis and Aged Country Cured Hams
Authors: Bullerman Lloyd B. , Hartman Paul A. , Ayres John C.
Published: December 2020

Italian-type salamis contaminated with
Aspergillus flavus
were more likely to develop aflatoxins during aging than were smoked Hungarian-type salamis under the same conditions. Temperatures below 15 C and humidities of less than 75% were found to prevent aflatoxin development during the aging of salami. The aging of salami for 8 weeks and the presence of curing ingredients, especially pepper and sodium nitrite, tended to reduce the amounts of aflatoxins found. Aflatoxins were produced by
A. flavus
and
A. parasiticus
on 6- to 9-month-old country cured hams during aging when the temperature approached 30 C.
Yellow Fever Virus. II. Factors Affecting the Plaque Neutralization Test
Authors: Spector Sheldon L. , Tauraso Nicola M.
Published: December 2020

In studies on the factors and conditions influencing the yellow fever (YF) virus plaque neutralization test, 60 min was found to be the minimal time necessary for equilibration of the virus-antibody complex at 23 and 37 C. Maximal virus titers in the diluent controls and the pre- and postinoculation serum-containing mixtures occurred by the 60-min adsorption time. Serum neutralization indices also seemed to level by this time. Heating (56 C for 30 min) decreased the neutralizing capacity of serum. However, the slope of the neutralization curve was not affected. The addition of native (unheated) “serum factor” in the form of fresh guinea pig or monkey sera partially restored the neutralizing activity lost by heating in some, but not all, sera. Many sera contained nonspecific inhibitors of YF virus infectivity and neutralization. Preliminary studies with ether extraction suggest that these inhibitors are lipid in nature.
Effect of Mixed Cultures on Antibiotic Susceptibility Testing
Authors: Shahidi Azra , Ellner Paul D.
Published: December 2020

Careful studies of the antibiotic susceptibilities of mixtures of bacteria likely to be encountered in clinical cultures have shown that the results obtained are completely unreliable. Mixtures of resistant and sensitive species appeared either as “resistant” or “sensitive” depending upon the organisms and the drug. A number of sensitive species gave reactions interpreted as resistant when tested in combination. Since reactions of bacterial mixtures are completely unpredictable, the authors emphasize that antibiotic susceptibility testing be limited to pure cultures.
Effect of the Fluorescein to Protein Ratio on Anti-
Treponema pallidum
Conjugates
Authors: Mothershed Susan M.
Published: December 2020

The effect of using different labeling techniques and various amounts of fluorescein-isothiocyanate was tested with several pools of antisera to
Treponema pallidum
. Optimal labeling occurred in all serum pools at a fluorescien to protein ratio of 15. The use of pure dye and the dialysis method of labeling is recommended as the method of choice because of its effectiveness in the reduction of nonspecific staining.
Production of Interferon in Serum-Free Human Leukocyte Suspensions
Authors: Strander H.
Published: December 2020

The recovery of interferon from Sendai-infected suspensions of purified human leukocytes is dependent on the serum concentration in the incubation medium. Very little interferon is obtained from serum-free suspensions. The data reported demonstrate that the critical macromolecular, age-independent, and species-unspecific serum principle can be omitted from the suspensions if the medium is supplemented with a combination of crystalline serum albumin and high concentrations of any one of five studied dipolar ionic buffers [
N,N
-bis(2-hydroxyethyl) glycine (Bicine),
N
-2-hydroxyethylpiperazine-
N
′-2-ethanesulfonic acid (HEPES), 2-(
N
-morpholino)ethanesulfonic acid (MES),
N
-tris(hydroxymethyl)methyl-2-amino-ethanesulfonic acid (TES), and
N
-tris(hydroxymethyl)methylglycine (Tricine)]. The optimal combination [TES (1.0%, w/v) and bovine serum albumin (0.8%, w/v)] allows the production of potent preparations of serum-free human interferon.
Standardized Viral Hemagglutination and Hemagglutination-Inhibition Tests. I. Standardization of Erythrocyte Suspensions
Authors: Hierholzer John C. , Suggs Morris T.
Published: December 2020

A spectrophotometric procedure for standardizing red blood cell suspensions for use in viral hemagglutination tests is described. The procedure is based on highly reproducible cyanmethemoglobin absorbance readings at 540 nm on any suitable spectrophotometer. Target values for milligrams of cyanmethemoglobin per 100 ml are given for the red cell suspensions of all mammalian and avian species employed in viral hemagglutination tests. By use of these values and a cyanmethemoglobin standard curve for a particular photometer, approximate 4% erythrocyte suspensions can be diluted to any lesser concentration. Coefficients of variation for the various diluted suspensions range from 4 to 7%.
Automated Instrument for the Fluorescent Treponemal Antibody-Absorption Test and Other Immunofluorescence Tests
Authors: Binnings Gerald F. , Riley Mel J. , Roberts Merritt E. , Barnes Richard , Pringle Thomas C.
Published: December 2020

An automated diagnostic test instrument and its development program are described. The instrument automates the fluorescent treponemal antibody-absorption test for syphilis to the extent that only 4 hr of technician time is required to conduct approximately 200 tests daily. Evaluation to date suggests its efficacy. In addition, preliminary studies indicate the feasibility of detecting antibodies to
Toxoplasma gondii, Plasmodium malariae
, and nucleoprotein (antinuclear factor). The instrument would seem to have broad application for routine and research immunofluorescence testing. Two elements comprise the instrument: a slide processor and a microscope attachment. The slide processor is an electro-pneumatically actuated device which automatically feeds special laboratory slides, on which antigen or other reagents are prefixed, through a series of operations which provide reagent application, incubation, washing, drying, and stacking of the finished slides for readout. The instrument provides flexibility in that incubation time and temperature as well as point, sequence, and duration of reagent application can be varied to accommodate a variety of immunofluorescence techniques. The microscope attachment can be fitted to all conventional dark-field fluorescence microscopes and makes possible the reading of three to six slides per minute. The reacted slides from the processor are injected sequentially onto the stage of the microscope by movement of a lever. As injected, slides are automatically in visual focus; fine focus is occasionally required. Scanning of the reacted field is accomplished by means of the normal microscope controls. A buffered glycerol coupling is maintained between the darkfield condenser substage lens and the slide cover glass by means of a pushbutton-actuated feed system.
In Vitro Activity of Coumermycin A
1
Authors: Fedorko Joseph , Katz Sol , Allnoch Hedi
Published: December 2020

The in vitro activity of coumermycin A
1
was compared with that of novobiocin, ampicillin, and minocycline. Coumermycin was found to be the most active antibiotic of the four against
Staphylococcus aureus
. It was about 50 times more active than novobiocin or minocycline against the strains tested. Coumermycin also showed good activity against group A streptococci and pneumococci, moderate activity against
Escherichia coli
, indole-positive
Proteus
species, and
Pseudomonas aeruginosa
, and poor activity against
Klebsiella-Enterobacter
and enterococci. Against
P. mirabilis
, however, coumermycin activity was almost equal to that of ampicillin. The new antibiotic was further found to be greatly reduced in activity in the presence of plasma, but its minimal inhibitory concentration was not greatly affected by inoculum size. Coumermycin was found to be bacteriostatic in its action, and resistance to it developed slowly. Also, cross-resistance was present with novobiocin but absent with ampicillin or minocycline.
Bacterial Immunoabsorbent Columns
Authors: Thomson R. O. , Walker P. D. , Harris E.
Published: December 2020

Methods are described for the preparation of bacterial immunoabsorbents consisting of organisms dispersed in agar beads 50 to 200 μm in diameter. The concentration of organisms could be made extremely high and columns prepared had sufficient capacity to enable them to be used for a number of purposes, but particularly for the removal of cross-reacting agglutinins from production batches of type-specific antisera. The absorptive capacity of these columns was regenerated after absorption by the elution of agglutinins with low
p
H buffers. Results obtained from the use of these immunoabsorbents are presented.