bluuebunny/crossref_metadata_2025 huggingface dataset:
Increase in Isoleucine Accumulation by α-Aminobutyric Acid-Resistant Mutants of
Serratia marcescens
Authors: Kisumi Masahiko , Kato Jyoji , Komatsubara Saburo , Chibata Ichiro
Published: December 2020

Several α-aminobutyric acid-resistant (Abu-r) mutants of
Serratia marcescens
were found to be superior to the parent strain in converting
d
-threonine to
l
-isoleucine. One of them accumulated 1.5 times more
l
-isoleucine that the parent strain. The level of acetohydroxy acid (AHA) synthetase in this mutant increased twofold above that of the parent strain. In the parent strain, AHA synthetase was repressed and
l
-isoleucine accumulation was decreased by either
l
-valine or
l
-leucine, whereas in the mutant the AHA synthetase level and
l
-isoleucine accumulation were not affected by these amino acids. AHA synthetase of the Abu-r mutant was feedback-inhibited by
l
-valine to the same extent as that of the parent strain. The level of
d
-threonine dehydratase in both strains was only slightly affected by several amino acids tested.
l
-Threonine dehydratase of the parent strain and of the mutant was almost completely inhibited by
l
-isoleucine. These results indicate that the increase in
l
-isoleucine accumulation by Abu-r mutants is due to the genetic derepression of AHA synthetase.
Serological Analysis of Morphologically and Biochemically Similar
Streptomyces
Species
Authors: Guthrie R. K. , Kocsis I. , Lassiter C. B.
Published: December 2020

Descriptions of morphological and biochemical characteristics of
Streptomyces
species have resulted in groups of isolates which appear to be identical or very closely related. Serological analysis has been used to confirm this relationship in some cases and to demonstrate differences in others.
Method for Measuring Mineralization in Lake Sediments
Authors: Harrison Michael J. , Wright Richard T. , Morita Richard Y.
Published: December 2020

A method is described for measuring the mineralization of an organic solute (
14
C-glucose) by the heterotrophic indigenous bacteria in lake sediments. Since there is no suitable procedure for the determination of in situ microbial activities in sediments, the procedure described is probably the best devised so far and may serve as a base for a more definitive procedure.
Method for the Preservation of Diagnostic Sera for Field and Laboratory Work
Authors: Smith Harry L. , Mandle Robert J.
Published: December 2020

Paper discs impregnated with antiserum, lyophilized, and stored at temperatures ranging from −21 to 33 C have yielded potent and specific reagents when rehydrated 370 days later. Applications are discussed.
Medium for Toxin Production by
Clostridium perfringens
in Continuous Culture
Authors: Chou Grace
Published: December 2020

A tryptone-salts medium for continuous growth and alpha toxin production of
Clostridium perfringens
type A in an adapted chemostat is described. In such steady-state cultures, fermentative and biochemical activity of
C. perfringens
remained unchanged. Toxigenic ability to produce alpha, theta, and nu toxins was preserved.
“Spore Plate Method” for Transformation of Steroids by Fungal Spores Entrapped in Silica Gel G
Authors: Hafez-Zedan Hamdallah , Plourde Rosaire
Published: December 2020

A new technique for investigating steroid biotransformations involving the use of glucose-treated Silica Gel G thin-layer chromatography plates spotted with fungal spores and steroid substrates is described. The conversion is followed by the detection and identification of steroid metabolites and is carried out on single plates by using the spores of different fungi. During the entire process, the spores remain on the original spots and microscopical examination revealed no germination. The method was successfully applied to as little as 30 μg of substrates, and a single plate could be used to detect the steroid metabolizing activity of spores of as many as 15 different cultures.
Microflocculation Assay for Gonococcal Antibody
Authors: Reising Gilbert
Published: December 2020

An antigen suspension consisting of cholesterol-lecithin particles sensitized with an extract of gonococci was used in a flocculation assay for the detection of human antibodies to
Neisseria gonorrhoeae.
With culturally and clinically diagnosed cases of uncomplicated gonorrhea, sera from 70 (49.6%) of 141 males and 207 (79.0%) of 262 females were reactive in the assay. Sera from four (7.3%) of 55 males and 11 (5.4%) of 203 females, all presumed normal, were reactive. The assay utilized equipment available in most clinical and public health laboratories.
Prolonged
Salmonella
Contamination of a Recreational Lake by Runoff Waters
Authors: Claudon David G. , Thompson Donald I. , Christenson Eleanor H. , Lawton Gerald W. , Dick Elliot C.
Published: December 2020

In the summer and fall of 1968, various
Salmonella
serotypes were isolated from a portion of Lake Mendota, the major recreational lake for Madison Wis. The apparent sources of these organisms were a residential storm sewer and a University of Wisconsin Experimental Farms' washwater drain. Salmonellae were isolated with regularity from a swimming beach located approximately 0.5 mile (0.8 km) from these sources.
Microbial Flora of Pond-Reared Brown Shrimp (
Penaeus aztecus
)
Authors: Vanderzant C. , Nickelson R. , Judkins P. W.
Published: December 2020

Agar plate counts and microbial types are reported for brown shrimp reared in 2-acre natural marshland and in 0.5-acre artificial ponds during June to October 1970. Bacterial counts of pond-reared shrimp ranged from 5 × 10
4
to 5.5 × 10
6
per g. At final harvest in October, bacterial counts ranged from 2 × 10
5
to 5.5 × 10
6
per g. In marsh ponds, bacterial counts of shrimp and pond water were lowest in August when both water temperature and salinity were high. Coryneform bacteria and to a lesser extent
Vibrio
were the predominant isolates from fresh pond shrimp. Shrimp stored at 3 to 5 C for 7 days were acceptable as judged by appearance and odor. Between 7 and 14 days of refrigerated storage, bacterial counts increased sharply and about 50% of the samples became unacceptable. Refrigerated storage of pond shrimp caused increases in coryneform bacteria and micrococci and decreases in
Vibrio, Flavobacterium, Moraxella
, and
Bacillus
species.
Pseudomonas
species were not significant in fresh or stored pond shrimp. The microbial flora of pond water usually was dominated by coryneform bacteria,
Flavobacterium, Moraxella
, and
Bacillus
species.
Initiation of Staphylococcal Growth in Processed Meat Environments
Authors: Genigeorgis Constantin , Savoukidis Minas , Martin Sue
Published: December 2020

The probability of staphylococcal growth initiation in laboratory-made cured meats is investigated and compared with growth initiation in broths.
Detection of
Leptospira
in Soil and Water by Immunofluorescence Staining
Authors: Henry Ronald A. , Johnson Russell C. , Bohlool B. B. , Schmidt E. L.
Published: December 2020

Specific immunofluorescence staining was used for the detection of leptospires in soil and water under laboratory and field conditions.
Specific Assay of Aminoglycosidic- or Polymyxin-Type Antibiotics Present in Human Sera in Combination with Cephalosporins
Authors: Stroy S. Ann , Preston David A.
Published: December 2020

Monitoring of serum concentrations of aminoglycosidic or polymyxin antibiotics when administered concurrently with cephalosporins or penicillins requires a special assay technique. Selective enzymatic degradation of the β-lactam antibiotic from the serum specimen allows subsequent assay of the antibiotic being monitored. This report gives details of a simple procedure for laboratory production of a crude enzyme capable of degrading cephalosporins or penicillins. An assay procedure for quantitating aminoglycosidic or polymyxin antibiotics after enzymatic degradation of a coexisting β-lactam antibiotic is described.
Preparation and Ultraviolet Light-Induced Transformation of an Antifungal Mixture of Heptaene Antibiotics of
Streptomyces surinam
Authors: Siewert Gerhard , Kieslich Klaus
Published: December 2020

Conditions for the production and isolation of an antifungal antibiotic mixture (DJ400) were investigated. Different preparations of DJ400 may contain at least 12 different heptaenes, which were characterized by partition chromatography (peak number) and ultraviolet (UV) spectra (types A, B, C). Irradiation with UV light transformed the predominant UV spectrum of type B into A. Comparison of untreated and UV-irradiated products indicated that the main components may exist in two forms with identical structures except for an all
trans
-heptaene system in A compounds and one internal
cis
double bond in B compounds. The ratio of the major components 6B and 8B depended on the media composition. Component 4B is probably a precursor of 6B; 10B and 12 may be precursors of 8B.
Improved Isolation of Anaerobic Bacteria From the Gingival Crevice Area of Man
Authors: Gordon D. F. , Stutman M. , Loesche W. J.
Published: December 2020

A roll tube technique (Hungate method) was employed in an attempt to cultivate a maximal portion of the organisms in the gingival crevice area of man. This technique achieves an anaerobic state by flushing the local environment with oxygen-free gas. Once collected, the crevicular debris was immediately placed into sterile oxygen-free test tubes which were flushed out by the oxygen-free gas. In this manner, the samples were weighed, dispersed, diluted, and cultured in roll tubes and plates. The medium for control (Brewer Jar technique) and Hungate techniques was Heart Infusion Agar fortified with 10% defibrinated horse blood. When the Hungate technique was used, the recovery of viable bacteria, as a percentage of the direct microscopic count, was significantly greater than plates incubated aerobically or utilizing the Brewer Anaerobic technique. Cultural counts by using the Hungate method averaged 41.3% for six samples when 90% nitrogen and 10% hydrogen were used, 70.4% for eight samples when 85% nitrogen, 10% hydrogen, and 5% carbon dioxide were used, and 63.4% for eight samples when 100% carbon dioxide was the gaseous atmosphere. At no time were cultural counts, by using anaerobic plates (Brewer Jar), more than 24% of the direct microscopic count. This suggests that exclusion of oxygen and the presence of carbon dioxide maximized recovery of gingival crevice bacteria.
Safe, Convenient Pipetting Device
Authors: Songer J. R. , Sullivan J. F. , Monroe J. W.
Published: December 2020

A finger-mounted pipetting device which can be fabricated in the laboratory is described.
Attempts to Demonstrate Hemagglutination and Hemadsorption by Respiratory Syncytial Virus
Authors: Richman Alan V. , Pedreira Frank A. , Tauraso Nicola M.
Published: December 2020

Extensive attempts to demonstrate a hemagglutinin of respiratory syncytial virus by both hemagglutination and hemadsorption tests failed. Hemagglutination tests were performed with red blood cells from 12 different animal species and at various temperatures and
p
H.
Toxicity to Chicks of
Aspergillus
and
Penicillium
Species Isolated from Moldy Pecans
Authors: Doupnik Ben , Bell D. K.
Published: December 2020

Isolates of
Aspergillus chevalieri, A. flavus, A. ochraceus, A. repens
, and
Penicillium funiculosum
and complexes of
P. citrinum-P. implicatum
isolated from moldy pecan meats were toxic to chicks.
Determination of Hydrogen Sulfide in Fermentation Broths Containing SO
2
Authors: Acree T. E. , Sonoff Elisabeth P. , Splittstoesser D. F.
Published: December 2020

A procedure for the determination of hydrogen sulfide in fermentation broths containing up to 100 μg of SO
2
per ml is described. The method involves the sparging of H
2
S from the broth into a cadmium hydroxide absorption solution, the formation of methylene blue from the absorbed sulfide, and the measuring of this color spectrophotometrically. The use of cadmium hydroxide instead of zinc acetate, the common absorbent, substantially reduced the interference of SO
2
with the analysis.
Comparison of Media for Isolation of Salmonellae and Shigellae from Fecal Specimens
Authors: Dunn Corwin , Martin William J.
Published: December 2020

Five transport media, eight plating media, and three enrichment broth media for the isolation of salmonellae and shigellae were evaluated. Eight laboratories in widely separated regions of the United States participated in this evaluation by submitting 490 fecal specimens in the transport media provided. The results suggest that the newer transport media may not offer any advantage over the use of buffered glycerol-saline in the isolation of these enteric pathogens. Shigellae were best isolated by direct inoculation, whereas salmonellae were isolated in greater numbers after tetrathionate (without Brilliant Green) enrichment with subsequent culturing on the plating medium. The use of a variety of plating media is recommended for the recovery of a larger number of these enteric pathogens.
In Vitro Susceptibility of Atypical Mycobacteria To Rifampin
Authors: Molavi Abdolghader , Weinstein Louis
Published: December 2020

Atypical mycobacteria (209 strains) were examined for susceptibility to rifampin by the proportion method by using Middlebrook 7H-10 agar. All strains of
Mycobacterium kansasii
and tap-water scotochromogens were inhibited by 0.25 to 1 μg of the drug per ml. Seventy-six per cent of
M. scrofulaceum
and 61% of
M. intracellulare
strains were susceptible to 4 μg/ml or less; 5% of the former and 8% of the latter were resistant to 16 μg/ml. All strains of
M. gastri
and
M. triviale
and most strains of
M. terrae
were sensitive to 1 to 4 μg/ml. Two strains of
M. borstelense
were both inhibited by 8 μg/ml. Nearly all strains of
M. fortuitum
were resistant to the drug. The results of this study suggest that rifampin may be a valuable agent for the treatment of many atypical mycobacterial infections.
Bacteriophage Types and O Antigen Groups of
Escherichia coli
from Urine
Authors: Marsik Frederic J. , Parisi Joseph T.
Published: December 2020

Urinary strains of
Escherichia coli
from seven geographical regions were typed serologically for O-specific antigens and with phages capable of lysing the majority of urinary isolated. The O antigen groups 4, 6, 75, 1, 50, 7, and 25 were the common ones found. Of the 454 cultures tested, 66.1% were phage typable and 65.2% were serotypable with the 48 antisera employed. Also, 71.6% of the cultures for which an O group could be determined were phage typable. Furthermore, of those seven O-antigen groups implicated in urinary tract infection, 80.2% exhibited a phage pattern. Various phage types were found within an O-antigen group, and, although one phage type associated a high percentage of the time with one O-antigen group, no correlation was observed between other O-antigen groups and phage types. Studies with bacteriuric patients by phage typing showed the presence of two strains of
E. coli
within an O-antigen group. Serogrouping and phage typing of fecal isolates of
E. coli
revealed the presence of some O-antigen groups and phage types also found as predominant types among urinary isolates. Phage typability correlated highly with hemolysis of human erythrocytes. Elevated temperatures of incubation and a chemical curing agent were used to enhance typability of cultures refractory to the typing phages. Phage typing, due to its rapidity, ease, and ability to distinguish strains of
E. coli
within an O-antigenic group, is suggested as a possible method by which a better insight into the epidemiology of urinary tract infections may be obtained.
Microbial Epoxidation of
cis
-Propenylphosphonic to (−)-
cis
-1,2-Epoxypropylphosphonic Acid
Authors: White R. F. , Birnbaum J. , Meyer R. T. , ten Broeke J. , Chemerda J. M. , Demain A. L.
Published: December 2020

Eighteen species of
Penicillium
, one of
Oidium
and one of
Paecilomyces
were found to effect a stereospecific conversion of
cis
-propenylphosphonate to fosfomycin which was identified by paper chromatography and gas-liquid chromatography (GLC) of the trimethylsilyl esters.
Penicillium spinulosum
carried out the epoxidation only after the glucose substrate had been utilized. Glucose controlled the epoxidation since its residual concentrations in the broth severely depresses the reaction. At optimum levels of glucose, an epoxidation efficiency approaching 90% of olefin charged (0.2 g/liter) was obtained after 10 days of incubation. The olefin concentration could be increased to 0.5 g/liter when glucose was replaced by glycerol, whereby a 90% conversion to fosfomycin was attainable in 6 days. The high conversion efficiency, a good agreement between the GLC assay and bioactivity, are indicative of the levorotatory nature of the product.
Automation of a Hemagglutination-Inhibition Test for Parainfluenza 3 Antibodies in Bovine Sera
Authors: Webert Donald W. , Cohen Daniel
Published: December 2020

An automated hemagglutination-inhibition (HI) test for the “shipping fever” strain (SF-4) of parainfluenza 3 antibody in bovine sera was developed and compared to manual tube and microtiter test procedures. The automated system operating at 60 samples per hr provided the most test results per specified time period, and the manual tube test provided the least. The manual microtiter test and the automated system at 40 samples per hr, falling between the two above procedures, were comparable in the number of sera that could be titrated in 1 day by one technician. There was little difference between automated and manual test reproducibility when measured at the twofold titer one-dilution difference level. However, the automated system titrated a higher number of sera at the same titer on repeat runs than either of the manual test procedures. The automated one-quartile difference reproducibility (each twofold dilution subdivided into 4 units—“quartiles”) was equal to the manual test one-dilution difference reproducibility. The standard deviation of the per cent variation from the mean of paired serum titers for 40-sample-per-hr runs ranged from ±3.49 to ±5.36%. The manual and automated systems were of comparable sensitivity in their detection of negative sera.
Preparation of Labeled Aflatoxins with High Specific Activities
Authors: Hsieh D. P. H. , Mateles R. I.
Published: December 2020

Resting cells of
Aspergillus parasiticus
ATCC 15517 were used to prepare highly labeled aflatoxins from labeled acetate. High synthetic activity in growing cells was evidenced only during 40 to 70 hr of incubation. Glucose was required for high incorporation efficiency, whereas the concentration of the labeled acetate determined the specific activity of the product. When labeled acetate was continuously added to maintain a concentration near but not exceeding 10 m
m
, in a culture containing 30 g of glucose per liter, 2% of its labels could be recovered in the purified aflatoxins which have a specific activity more than three times that of the labeled acetate.
Effect of Rehydration on Recovery, Repair, and Growth of Injured Freeze-Dried
Salmonella anatum
Authors: Ray B. , Jezeski J. J. , Busta F. F.
Published: December 2020

From 70 to 90% of the
Salmonella anatum
cells that survived freeze-drying in nonfat milk solids were injured. After rehydration, these injured survivors failed to grow on a selective plating medium containing deoxycholate but could form colonies on a nonselective medium. In a suitable environment after rehydration, injury disappeared in most of these cells. The rate of this repair at 25 C was very rapid initially and, in a medium containing milk solids, was completed within 1 hr after rehydration. The repaired cells initiated growth about 1 hr later than normal cells and grew at a slower rate. In a medium containing milk solids, initial recovery, extent of repair of injury, initiation of growth, and rate of growth were not influenced by supplementation with extra nutrients in other rehydration media. Rehydration controlled by modifying the concentrations of lactose, sucrose, or milk solids in the rehydration medium influenced the recovery of cells and the time that growth was initiated. Glycerol failed to increase recovery. Higher numbers of cells were recovered by rehydrating at 15 to 25 C, but an earlier initiation of growth and more rapid growth were observed at 35 C.
Characteristics of a Bacteriocin Derived from
Streptococcus faecalis
var.
zymogenes
Antagonistic to
Diplococcus peumoniae
Authors: Bottone Edward , Allerhand Jona , Pisano Michael A.
Published: December 2020

A bacteriocin-producing strain of
Streptococcus faecalis
var.
zymogenes
(E-1) was isolated from clinical material (conjunctiva). The active substance differed from bacteriocins described by other investigators primarily in its spectrum of antibacterial activity, especially by its marked inhibition of
Diplococcus pneumoniae.
The E-1 bacteriocin also inhibited nonhemolytic strains of enterococci as well as one-third of the Viridans group of streptococcal strains investigated. The degree of inhibition, however, as indicated by the size of the zones against the latter organisms, was significantly reduced. No activity was detected against any of the strains belonging to the following groups of bacteria: hemolytic enterococci, beta-hemolytic streptococci, nonhemolytic streptococci, staphylococci, and various gram-negative species. Similarly, three strains each of
Bacillus cereus
and
Listeria monocytogenes
and one strain of
Erysipelothrix insidiosa
were not inhibited. The bacteriocin was able to diffuse through bacterial membranes as well as cellulose dialyzer tubing. It was inactivated by heating to 80 C for 20 min but resisted inactivation by either trypsin or chloroform.
Large-Scale Purification of Rubella Virus and Preparation of an Experimental Split Rubella Virus Vaccine
Authors: Väänänen Pertti , Vaheri Antti
Published: December 2020

Large-scale purification of rubella virus from tissue culture fluid and preparation of an experimental rubella subunit vaccine are described. The virus, purified isopycnically in sucrose gradients, was Tween 80-ether treated, and the product was filtered sterile. The vaccines were of two types, formalinized and nonformalinized. They were not infectious, had only a slight pyrogenicity, and caused no harmful symptoms in animals. The immune response in guinea pigs was better when the nonformalinized vaccine was used and the dosage was 2,500 hemagglutinating units per injection (0.5 ml).
Chromomycin A
3
, an Antitumor Antibiotic: Tissue Distribution Studies in Mice as Measured by Microbial Assay
Authors: Pittillo Robert F. , Woolley Carolyn
Published: December 2020

A microbiological assay has been developed for chromomycin A
3
, an antitumor antibiotic showing promise in human trials. The assay bacterium is a derived strain of
Streptococcus faecalis
resistant to methotrexate. Studies with mice revealed that relatively high concentrations of this antibiotic were maintained in the blood, kidneys, and liver of mice after a single-dose intraperitoneal injection of the drug.
Antibiotic Susceptibilities of
Serratia marcescens
and
Enterobacter liquefaciens
Authors: Greenup Patsy , Blazevic Donna J.
Published: December 2020

Production of 5′-nucleotides by
Serratia marcescens
and
Enterobacter liquefaciens
correlates with deoxyribonuclease production, indicating the close relationship between these two organisms. To determine further relationships, susceptibilities of 279 strains of the tribe
Klebsielleae
were determined by the high-potency disc method, agar-dilution method, or both, by using 14 antibiotics. Ninety-seven per cent of
S. marcescens
(201 of 207 strains) and 100% of
E. liquefaciens
(17 strains) had minimum inhibitory concentration (MIC) of 100 μg/ml or greater with colistin and polymyxin B. With these two antibiotics, 93% of other
Enterobacter
species (28 strains) had MIC values of less than 1.6 μg/ml, and 100% of
Klebsiella
(27 strains) had MIC values less than 1.6 μg/ml. Consistent patterns were not noted with the other antibiotics tested, but the results with colistin and polymyxin B provide additional evidence of the close relationship of
S. marcescens
and
E. liquefaciens.
Specific Distribution of R Factors in
Serratia marcescens
Strains Isolated from Hospital Infections
Authors: Schaefler S. , Winter J. , Catelli A. , Greene J. , Toharski B.
Published: December 2020

Serratia marcescens
strains from three hospitals in the city of New York were tested for antibiotic susceptibility patterns and the presence of transmissible antibiotic resistance factors. There appears to be a pattern characteristic for each hospital with regard to the sensitivity to nalidixic acid, tetracycline, chloramphenicol, and sulfonamides, whereas the resistance to ampicillin, cephalothin, and streptomycin is similar in the strains isolated from all three hospitals. In one hospital, a single type of R factor was found which transfers resistance to streptomycin, kanamycin, ampicillin, and sulfonamides, whereas strains isolated from a second hospital transfer only ampicillin resistance. No R factors could be detected in multiply resistant
Serratia
strains isolated in a third hospital. The presence of a single type of R factor probably reflects the relative ecological isolation of
S. marcescens
and could be useful for epidemiological studies of hospital infections with
Serratia.
Rapid Methods for Determining Decarboxylase Activity: Ornithine and Lysine Decarboxylases
Authors: Goldschmidt Millicent C. , Lockhart Betty M. , Perry Katherine
Published: December 2020

A rapid biochemical method for the determination of ornithine and lysine decarboxylase (EC 4.1.1.18) activity has been developed for use in the routine clinical laboratory. It is based on the detection of the amine end product produced in response to the single key amino acid added to a synthetic medium. A modified ninhydrin reagent is used to detect the amine after a chloroform extraction. This procedure can be used with a 1- to 4-hr incubation period (utilizing an initial concentrated inoculum) or with an overnight culture. Thus, measurements based on the alkalinization of the medium after a lengthy incubation period are avoided. Optimal parameters for enzyme activity are discussed.
Rapid Methods for Determining Decarboxylase Activity: Arginine Decarboxylase
Authors: Goldschmidt Millicent C. , Lockhart Betty M.
Published: December 2020

A rapid biochemical method for the determination of arginine decarboxylase (EC 4.1.1.19) activity has been developed for use in the routine clinical microbiology laboratory and correlated with similar procedures for ornithine and lysine decarboxylase (EC 4.1.1.18) systems. It is based on the detection of agmatine, the amine end product formed during growth on a synthetic medium containing arginine as the key amino acid. A modified diacetyl reagent is used to detect this amine after a differential butanol extraction of the cultures. This procedure can be used to detect this amine after a 1- to 4-hr incubation period (with the use of an initial concentrated inoculum) or with an overnight culture. Thus, both an indirect measurement based on the alkalinization of the medium and a lengthy incubation period were avoided. Parameters for optimal enzyme activity and the pertinent enzyme systems involved in arginine and agmatine catabolism are discussed in detail.
Effect of Plate Size and Location of Disc on Zone Diameter in the Disc Antimicrobial Susceptibility Test
Authors: Bartlett Raymond C. , Mazens Mary F.
Published: December 2020

An established standard antimicrobial disc susceptibility test recommends the use of a 150-mm petri dish. Many workers substitute 100-mm plates and use various types of mechanical dispensers. A comparison of zone diameters was made by testing
Staphylococcus aureus
and
Escherichia coli
against penicillin and chloramphenicol with the use of these different sized plates and dispensers. Zone diameters were consistently smaller at the edges of plates than in the center (0.4 to 1.2 mm). Significant small differences of up to 1.2 mm or no differences were observed when the mean diameters from these various plates were compared. All of the zone diameter measurements fell within accepted values for analytical variability in this procedure. There is no evidence that any individual combination of plates, dispensers, or disc locations provides greater precision in zone diameter measurement. More difficulty was encountered in measuring zones at the periphery of small plates. This suggests that busy clinical laboratory workers might not produce work of comparable quality with the smaller plates.
l
-Asparaginase from
Proteus vulgaris
Authors: Tosa Tetsuya , Sano Ryujiro , Yamamoto Kozo , Nakamura Masatoshi , Ando Katsuko , Chibata Ichiro
Published: December 2020

To produce an immunologically and enzymologically new type of
l
-asparaginase, 108 strains of bacteria were screened for enzyme production. As a result, 13 bacteria belonging to the genera
Alcaligenes, Bacterium
, and
Proteus
were found to produce
l
-asparaginases in high levels. Among these
l
-asparaginases, partially purified
l
-asparaginases from
B. cadaveris
and
P. vulgaris
showed antitumor activity. A partially purified
l
-asparaginase preparation of
P. vulgaris
did not react with the antibody of
Escherichia coli
l
-asparaginase on the Ouchterlony agar plate. Culture conditions for the production of
l
-asparaginase by
P. vulgaris
were investigated in detail. The enzyme was produced in high yields when cells were grown aerobically in a medium containing sodium fumarate and corn steep liquor. The addition of glucose or ammonium ion to the medium, however, resulted in depressed production of
l
-asparaginase. Under the optimum conditions, 3,700 international units of
l
-asparaginase was obtained from 1 liter of culture medium.
Effect of Administered Interferon on Rabies in Rabbits
Authors: Postic Bosko , Fenje Paul
Published: December 2020

This study describes the effect of interferon on the survival of rabbits infected with a street strain of rabies virus. Interferon was prepared by collecting serum from rabbits injected with Newcastle disease virus and was characterized by biological and physicochemical methods. Rabbit serum interferon mixed and incubated with a suspension of rabies virus did not neutralize its infectivity. Rabbits were inoculated into the hind leg muscle with approximately 80 LD
50
of virus. Interferon was administered intravenously or intramuscularly, or by both methods, in the same or opposite leg as virus. Mortality due to rabies was significantly reduced by the concurrent administration of 8 × 10
5
units of interferon divided between the site of virus inoculation and intravenously. There was less protection if 3 hr elapsed between the inoculation of virus and interferon. Treatment given 24 hr after infection did not prevent death but prolonged the incubation period.
Microbial Penetration of Muslin- and Paper-Wrapped Sterile Packs Stored on Open Shelves and in Closed Cabinets
Authors: Standard Paul G. , Mackel Don C. , Mallison G. F.
Published: December 2020

Microbial penetration of sterile packs was studied using single-wrap (two layers) muslin, double-wrap (four layers) muslin, and two-way crepe paper (single layer) to wrap 20 gauze sponges (2 by 2 inch). These packs were stored in the central sterile supply departments of two hospitals and processed for sterility at predetermined intervals. Microorganisms penetrated single-wrap muslin as early as 3 days and double-wrap muslin and single-wrap two-way crepe paper in 21 to 28 days stored in open shelves. The time required for microbial penetration was at least twice as long when closed cabinets were used. Single-wrap muslin packs stored in sealed, impervious plastic bags remained sterile for at least 9 months. All sterile materials in pervious wrappers should be handled as little as possible and then only with extreme care and caution. Closed cabinets offer more protection than open shelves, and single wrappers are not recommended.
Bacteriology of Dehydrated Space Foods
Authors: Powers Edmund M. , Ay Carl , El-Bisi Hamed M. , Rowley Durwood B.
Published: December 2020

The initial bacteriological requirement established in 1964 for space foods by the U.S. Army Natick Laboratories are: a total aerobic plate count (≤ 10,000 per g), a total coliform count (≤ 10 per g), fecal coliforms (negative per gram), fecal streptococci (≤ 20 per g), coagulase-positive staphylococci (negative in 5 g) and salmonellae (negative in 10 g). Of the space foods and prototypes tested during 1968 and 1969, 93% complied with the total aerobic plate count, 98% had less than 1 coliform per g, and 99% were negative for fecal coliforms; 88% complied with the streptococci requirement; 100 and 98% were negative for staphylococci and salmonellae, respectively. Nineteen food samples which did not comply (as indicated parenthetically by actual counts per gram) with the requirements were (i) total aerobic plate count: beef soup and gravy base (18,000), chicken soup and gravy base (57,000), spaghetti with meat sauce (12,100 and 14,000), sugared coffee (> 300,000), chocolate ice cream cubes (20,000), and each of four samples of chocolate candy (12,000 to 61,000); (ii) coliforms: two out of three vanilla milk drinks (16 and 127) and one beef hash bar (14); (iii) fecal coliforms: one sample of chicken soup and gravy base positive; (iv) fecal streptococci: two samples of peanut cubes (40 and 108), coconut cubes (75), chicken soup and gravy base (2,650), beef soup and gravy base (33), and five out of six flavored milk drinks (23 to 300); (v) salmonellae: one each of chicken and beef soup and gravy base were positive.
Characterization of Two Psychrophilic
Pseudomonas
Bacteriophages Isolated from Ground Beef
Authors: Whitman P. A. , Marshall R. T.
Published: December 2020

Characterization studies were performed on two psychrophilic phages which were isolated from ground beef samples. Phage inactivation by exposure to heat, low
p
H, osmotic shock conditions, and freezing showed that these two isolates were different. One-step growth experiments indicated that one isolate had a burst size five times as large (500) and a latent period two times as long (4 hr) as the other when tested at 7 C. Nucleic acid type was 2-deoxyribonucleic acid for both. Electron micrographs showed one to belong to Bradley's phage group A and the other to phage group C.
Subtyping of Pyocin Type 1
Pseudomonas aeruginosa
: One Year of Experience
Authors: Rose Harold D. , Babcock Janice B. , Heckman Margaret G.
Published: December 2020

Subtyping of pyocin type 1
Pseudomonas aeruginosa
strains has increased the sensitivity of an epidemiological tool used by the Hospital Infection Committee in surveillance studies.
Dry-Heat Resistance of
Bacillus subtilis
var.
niger
Spores on Mated Surfaces
Authors: Simko G. J. , Devlin J. D. , Wardle M. D.
Published: December 2020

Bacillus subtilis
var.
niger
spores were placed on the surfaces of test coupons manufactured from typical spacecraft materials (stainless steel, magnesium, titanium, and aluminum). These coupons were then juxtaposed at the inoculated surfaces and subjected to test pressures of 0, 1,000, 5,000, and 10,000 psi. Tests were conducted in ambient, nitrogen, and helium atmospheres. While under the test pressure condition, the spores were exposed to 125 C for intervals of 5, 10, 20, 50, or 80 min, with survivor data being subjected to a linear regression analysis that calculated decimal reduction times. Differences in the dry-heat resistance of the test organism resulting from pressure, atmosphere, and material were observed.
Growth Temperatures and Temperature Characteristics of
Aeromonas
Authors: Rouf M. A. , Rigney Mary M.
Published: December 2020

Six of the 13
Aeromonas hydrophila
, 1 of 10
A. shigelloides
, and none of 10
A. salmonicida
were found to be psychrophiles. All of the rest of the strains were mesophiles. The μ values (temperature characteristics) could not be used to distinguish psychrophiles from mesophiles.
Electronic Counting in Growth Studies of
Mycobacterium avium
Authors: McCarthy Charlotte
Published: December 2020

Metabolically uniform cells of
Mycobacterium avium
were obtained by selective filtration. The life cycle of these cells was followed by photomicrographs, electronic enumeration, and sizing and by viability and protein determinations. The cells elongate to form filaments several times their initial length; the increase in mass is reflected by a five- to sixfold increase of total protein in the culture. The filaments then fragment causing the production of viable coccobacilli. The techniques employed to obtain this form of growth are described and comparisons with nocardial growth are noted.
Role of
p
H and Nitrogen Limitation in the Elaboration of the Extracellular Polysaccharide Pullulan by
Pullularia pullulans
Authors: Catley B. J.
Published: December 2020

During the growth of the yeastlike fungus
Pullularia pullulans
on glucose as sole carbon source, the cell-mass does not increase concomitantly with the elaboration of the extracellular polysaccharide pullulan, but precedes it. The conditions generated in the culture medium which activate the secretion of polysaccharide have been sought for, and, in particular, the roles of extracellular
p
H and nitrogen limitatation are examined.
Disc Plate Method of Microbiological Antibiotic Assay
Authors: Davis W. W. , Stout T. R.
Published: December 2020

Several factors are investigated that normally cause variation in zone diameters in conventional disc plate diffusion assay procedures. Of these factors the most serious is the unequal exposure of the individual plates at top or bottom of stacks to temperatures above and below room temperature. This unequal temperature exposure is avoided by novel handling and incubation procedures. A major variable, but one which can be controlled, is the varying time interval between pouring seeded agar and the time of applying the pads with antibiotic to the plates. This influence of time of setting and the effects of several other sequential operations are combined into a composite variable. This variable is then accounted for and normalized by interposing “external” reference plates set with a reference solution in the sequence of approximately 100 plates. No “internal” reference zones are employed. Such factors as volume of agar poured, wedge shape of agar in a dish, volumetric errors in dilutions, and timing considerations are studied and discussed. The results of this study form the basis for a test protocol which is presented in a following paper.
Practical Procedures for the Purification of Bacterial Viruses
Authors: Bachrach Uriel , Friedmann Adam
Published: December 2020

The efficiencies of the various methods used for phage concentration have been compared. The two-phase concentration method (with polyethylene glycol and dextran sulfate) gave maximal recoveries of infectivity for coliphages of the T-even and T-odd series and for ribonucleic acid phages and single-stranded deoxyribonucleic acid phages. Precipitation of phages by acid gave high yields when applied to T2 and T4 phages but not with T3 and T7 coliphages. Differential centrifugation was efficient when sedimented phages were gently dispersed before repeating the centrifugation cycle. The efficiencies of the various methods have also been confirmed by electron microscope studies, which also show that the two-phase concentration method gave rise to intact phages. Zone centrifugations in sucrose gradients (12.5 to 52.5%) indicated that coliphages of the T-even series sediment faster than T-odd coliphages; they may thus be separated from each other and from empty ghosts by centrifugation at 100,000 ×
g
for 40 min. Equilibrium centrifugation in preformed cesium chloride gradients was also useful for phage concentration and purification. This study also deals with some optical properties of purified phages; optical cross sections and absorbance ratios (at 260 and 280 nm) of the various preparations are given.
Synthesis of
l
-3, 4-Dihydroxyphenylalanine from
l
-Tyrosine by Microorganisms
Authors: Haneda Katsuji , Watanabe Shiro , Takeda Isao
Published: December 2020

l
-3, 4-Dihydroxyphenylalanine can be synthesized efficiently from
l
-tyrosine under acidic conditions by
Aspergillus oryzae
and other fungi.
Lack of Toxicity of
Helminthosporium maydis
-Invaded Corn and Culture Filtrates to Chicks and Mice
Authors: Doupnik Ben , Jones Oscar H. , Peckham John C.
Published: December 2020

Six isolates of
Helminthosporium maydis
, obtained from southern leaf blight-damaged corn, were grown separately on autoclaved corn and fed to chicks and mice to evaluate their toxigenicity. Two-, three-, and four-week-old culture filtrates from three pathogenic isolates grown separately on modified Fries medium were also evaluated for toxigenicity. None of the invaded corn samples or culture filtrates affected the weights of chicks or mice when compared to controls. Postmortem examinations did not reveal significant gross lesions.
H. maydis
was not toxigenic under our experimental conditions.
Influence of Temperature on Substrate and Energy Conversion in
Pseudomonas fluorescens
Authors: Mennett Randall H. , Nakayama T. O. M.
Published: December 2020

The influence of temperature on yield, maintenance rate, growth rate, and conversion of calories to biomass was studied with
Pseudomonas fluorescens
grown in a chemostat. Maintenance and growth rate are influenced linearly with temperature. Both rates increased with increasing temperature and gave linear Arrhenius plots over a limited range. Cells harvested during the steady-state at each temperature were burned in a microcalorimeter. The number of kilocalories per gram (dry weight) of organism was not influenced significantly by the temperature during growth, indicating that the conversion of substrate calories into biomass is apparently regulated in the range of temperature studied.
Parameters of Rumen Fermentation in a Continuously Fed Sheep: Evidence of a Microbial Rumination Pool
Authors: Hungate R. E. , Reichl J. , Prins R.
Published: December 2020

The feed and feces of a continuously fed sheep were analyzed for carbon, hydrogen, and nitrogen, with oxygen as the remainder. The daily feed-feces weight difference was used as the reactant in an equation representing the rumen fermentation. The measured products were the daily production of volatile fatty acids (VFA), CH
4
, CO
2
, and ammonia. The carbon unaccounted for was assumed to be in the microbial cell material produced in the rumen and absorbed before reaching the feces. The ratio of C to H, O, and N in bacteria was used to represent the elemental composition of the microbes formed in the rumen fermentation, completing the following equation:C
20.03
H
36.99
O
17.406
N
1.345
+ 5.65 H
2
O → C
12
H
24
O
10.1
+ 0.83 CH
4
VFA + 2.76 CO
2
+ 0.50 NH
3
+ C
4.44
H
8.88
O
2.35
N
0.785
microbial cells absorbed With C arbitrarily balanced and O balanced by appropriate addition of water, any error is reflected in the H. The H recovery was 98.5%. The turnover rate constant for rumen liquid equilibrating with polyethylene glycol (PEG) was 2.27 per day. Direct counts and volume measurements of the individual types of bacteria and protozoa in the rumen were used to calculate the total microbial cell volume in the rumen, not equilibrating with it. The dry matter in the rumen (582 g) and the nitrogen content (12.05) of the microbes in the rumen were estimated, the latter constituting 85% of the measured N in the rumen. Calculations for rumen dry matter and nitrogen turning over at the PEG rate introduce big discrepancies with other parameters; a rumination pool must be postulated. Its size and composition are estimated. Arguments are presented to support the view that dry matter and some of the microbes, chiefly the protozoa, do not leave the rumen at the PEG rate. One experiment with the same sheep fed twice daily showed significantly less production of microbial cells than did the continuous (each 2 hr) feeding. Analysis of the microbial cell yield suggests that, on the basis of 11 mg of cells per adenosine triphosphate molecule, a maximum of six adenosine triphosphate molecules could have been formed from each molecule of hexose fermented.
Detection of Arginine Dihydrolase in Nonfermentative Gram-Negative Bacteria by Use of Thin-Layer Chromatography
Authors: Williams Gary A. , Blazevic Donna J. , Ederer Grace M.
Published: December 2020

Thin-layer chromatography was used to detect the presence of the arginine dihydrolase system in nonfermentative gram-negative bacteria. The test was positive for the fluorescent pseudomonads as well as
Pseudomonas maltophilia,
whereas other
Pseudomonas
sp.,
Mima,
and
Herellea
were negative. This procedure can be completed in a few hours and may be useful in the clinical laboratory.
Tobramycin (Nebramycin Factor 6): In Vitro Activity Against
Pseudomonas aeruginosa
Authors: Meyer R. D. , Young L. S. , Armstrong D.
Published: December 2020

Tobramycin (factor 6 of the nebramycin complex) is a new aminoglycoside antibiotic isolated from
Streptomyces tenebrarius
which is active against
S. aureus, Enterobacteriaceae
, and
Pseudomonas aeruginosa
. Susceptibility to tobramycin of 96 strains of
P. aeruginosa
, including 45 recent isolates from blood, was studied by using agar and broth dilution methods. The minimum inhibitory concentration (MIC) for 83 of 96 strains was 3.12 μg/ml or lower in Mueller Hinton agar; MIC values were two to eight times lower in Mueller Hinton broth tests. Agar dilution MIC values were generally lower than those obtained in parallel tests with gentamicin. Killing curves obtained from serial sampling of broth cultures showed a 100- to 10,000-fold decline in viability of log-phase organisms within 30 min of exposure to the drug. Two-dimensional agar dilution tests with carbenicillin and tobramycin with 79 strains showed additive or synergistic effects; no antagonism was documented. Seventy-eight of 79 strains were inhibited by a combination of 50 μg of carbenicillin per ml and 1.56 μg of tobramycin per ml, blood levels which seem attainable in man. Tobramycin appears to be a potent, rapidly bactericidal antibiotic against
P. aeruginosa
and merits clinical evaluation.
Antimicrobial Activity of Neomycin C Against
Staphylococcus epidermidis
Authors: Robertson John H. , Baas R. , Yeager R. L. , Tsuji Kiyoshi
Published: December 2020

In vitro studies indicate that neomycin C is 50% as active as neomycin B against
Staphylococcus epidermidis
(ATCC 12228).
Counter-Immunoelectrophoresis: Rapid Method for Detecting Group-Specific Antigen and Antibodies Associated with Oncogenic Ribonucleic Acid Viruses
Authors: Hoekstra John , Deinhardt Friedrich
Published: December 2020

Counter-immunoelectrophoresis was used for the quantitation of group-specific antigen and antibodies of C-type ribonucleic acid leukemia and sarcoma viruses.
Effects of Actinobolin on Growth and Some Metabolic Activities of Cariogenic Streptococci In Vitro and In Vivo
Authors: Keele Bernard B. , Powell Hubert L. , Navia Juan M. , McGhee Jerry
Published: December 2020

Actinobolin, a known inhibitor of protein synthesis, has been shown not to interfere selectively with acid production or dextransucrase activity in a cariogenic streptococcus when the antibiotic is added to a concentration of 500 μg/ml. It has also been shown that actinobolin does not alter the total in vivo flora of the oral cavity of the rat when tested in a rat caries model system. A culture of cariogenic streptococci, adapted to in vitro growth in the presence of 1 mg of actinobolin per ml, has also been isolated.
Prototype of a Fully Automated Device for Determination of Bacterial Antibiotic Susceptibility in the Clinical Laboratory
Authors: Isenberg Henry D. , Reichler Allen , Wiseman Donald
Published: December 2020

A completely automated system for the performance of antibiotic susceptibility tests in the clinical laboratory is described. With a modicum of personnel involvement, data on 40 specimens tested against 13 antibiotics are obtained every hour after an initial 3-hr period. The step by step explanation of the functioning of this prototype system, based on a thoroughly tested manual model, is presented. The system compares well with the standard diffusion test and has a potential for application to other endeavors of the clinical microbiology laboratory with a comparable saving in time and labor.