bluuebunny/crossref_metadata_2025 huggingface dataset:
Microbioassay of Antimicrobial Agents
Authors: Simon Harold J. , Yin E. Jong
Published: December 2020

A previously described agar-diffusion technique for microbioassay of antimicrobial agents has been modified to increase sensitivity of the technique and to extend the range of antimicrobial agents to which it is applicable. This microtechnique requires only 0.02 ml of an unknown test sample for assay, and is capable of measuring minute concentrations of antibiotics in buffer, serum, and urine. In some cases, up to a 20-fold increase in sensitivity is gained relative to other published standardized methods and the error of this method is less than ±5%. Buffer standard curves have been established for this technique, concurrently with serum standard curves, yielding information on antimicrobial serum-binding and demonstrating linearity of the data points compared to the estimated regression line for the microconcentration ranges covered by this technique. This microassay technique is particularly well suited for pediatric research and for other investigations where sample volumes are small and quantitative accuracy is desired. Dilution of clinical samples to attain concentrations falling with the range of this assay makes the technique readily adaptable and suitable for general clinical pharmacological studies. The microassay technique has been standardized in buffer solutions and in normal human serum pools for the following antimicrobials: ampicillin, methicillin, penicillin G, oxacillin, cloxacillin, dicloxacillin, cephaloglycin, cephalexin, cephaloridine, cephalothin, erythromycin, rifamycin amino methyl piperazine, kanamycin, neomycin, streptomycin, colistin, polymyxin B, doxycycline, minocycline, oxytetracycline, tetracycline, and chloramphenicol.
Evaluation of Three Cell Culture Systems as Substrates for Influenza Virus Assay
Authors: Goldstein Mark A. , Tauraso Nicola M. , Orr Henry C.
Published: December 2020

The propagation of various influenza virus strains in primary rhesus monkey kidney (RMK), primary hamster kidney (HK), and the MDCK-USD canine kidney (CK) cell cultures was compared. Virus-infected cultures were examined for cytopathic effect (CPE) and by performing the hemadsorption (HAd) technique. The highest HAd titers were found most often in HK, followed by RMK and CK. However, the CK cell line provided the best substrate for detecting CPE. Although influenza B strains tended to grow to higher titers, these strains produced less CPE than did the A strains.
Pulmonary Absorption and Retention of Kanamycin After Repeated Inhalation Administration of Kanamycin Aerosol
Authors: Teske Richard H. , Miller Stephen B.
Published: December 2020

The absorption and retention of kanamycin by the pulmonary system was evaluated after aerosol administration to rats. Tissue level concentrations of the drug were assayed by the agar-plate bioassay method. Mean concentrations of 6.58 μg/g and 3.52 μg/g were found in the lung and kidney homogenates, respectively, 26 hr after the final exposure period. No detectable level was found in the plasma.
Aerosol Survival of
Escherichia coli
B Disseminated from the Dry State
Authors: Cox C. S.
Published: December 2020

Survival was determined for
Escherichia coli
B disseminated as an aerosol from the dry state. Survival in nitrogen, like that for wet dissemination, was better at low than at high relative humidity (RH). At high RH, survival was characterized by critical zones of instability in survival as a function of RH, instability occurring at 100, 95, 78, 70, and 60% RH. In air, survival was inferior to that in nitrogen at low RH, whereas the converse was found at high RH. The effect was attributed to oxygen. In general, results support the conclusion that to the first approximation survival is related to bacterial water content, the latter increasing with RH. However, a more detailed analysis of results indicates that survival might not be exactly related to bacterial water content. It is shown that death occurred because of rehydration and that the pretreatment of
E. coli
B affected its aerosol stability characteristics; i.e., wet and dry disseminated aerosols are not equivalent.
Automated Microtitration Test for Antistreptolysin O
Authors: Dixon J. M. S. , Grocholski J. J.
Published: December 2020

A commercially available instrument that automatically makes serial dilutions and delivers reagents was used for the determination of antistreptolysin O titers in serum. The automated method was compared with tube-dilution and manual microtitration techniques. It gave higher reproducibility of results and was quicker to perform than both the other tests; and it was much more economical in reagents than the tube test. The automated technique is considered to be the best of the three methods when more than a small number of specimens are examined at one time. It is now in routine use in our laboratory.
Effect of
p
H of Medium and Size of Inoculum on Activity of Antibiotics Against Group D
Streptococcus (Enterococcus)
Authors: Toala Publio , Wilcox Clare , Finland Maxwell
Published: December 2020

Seventy-one clinical isolates of 5 species of group D
Streptococcus (Enterococcus)
were tested for susceptibility to 15 antibiotics at
p
H 5.0, 7.4, and 8.5. Penicillin G, ampicillin, cephalothin, cephaloridine, and novobiocin were considerably more active against all strains at
p
H 5.0 than in the more alkaline media. On the other hand, lincomycin, clindimycin, erythromycin, and gentamicin were moderately to markedly more active at
p
H 8.5. No important differences were noted in the susceptibility of the strains to kanamycin and streptomycin, at the
p
H levels tested, but the organisms were quite resistant to them in these tests. The various species differed quantitatively in their susceptibility to the individual drugs and in the effects of
p
H. The size of the inoculum also had a variable effect on susceptibility, depending on the species of
Enterococcus
, the antibiotics, and the
p
H of the test medium. The data suggest that, in the antibiotic treatment of urinary tract infections caused by
Enterococcus
, attempts should be made to achieve the optimum
p
H in the urine, particularly in view of the fact that organisms of this group are often resistant to several antibiotics in the usual tests.
Aerobic Heterotrophic Bacterial Populations of Sewage and Activated Sludge
Authors: Prakasam T. B. S. , Dondero N. C.
Published: December 2020

An activated sludge from a sewage treatment plant and a laboratory activated sludge developed on an artificial waste were compared for their ability to utilize 11 aromatic compounds. There were several significant differences between them. The laboratory sludge contained higher numbers of organisms and metabolized the aromatics to a greater extent. Laboratory activated sludges acclimated to utilization of the aromatics differed from each other in population structure and the pattern of oxygen consumption with aromatic substrates. The oxidative patterns of uncontrolled mixed populations were unreliable for investigating metabolic pathways. Extracts of the various sludges elevated the plate counts of the sludges.
Apparatus for the Determination of Heat Resistance of Spores
Authors: Cerf Olivier , Grosclaude Gérard , Vermeire Daniel
Published: December 2020

Apparatus for the rapid transfer of capillary tubes from a hot to a cold bath, by means of two pneumatic jacks, is described.
Errors Related to Different Techniques of Intraperitoneal Injection in Mice
Authors: Arioli V. , Rossi E.
Published: December 2020

We found a 12% error in the placement of intraperitoneal injections of mice with the one-man procedure of injection. With a two-man procedure, the incidence of error was consistently reduced to 1.2%.
Effect of Chloramphenicol on Host-Bacteriophage Relationships in the Lactic Streptococci
Authors: Erskine J. M.
Published: December 2020

Chloramphenicol (CM)-resistant mutants of
Streptococcus lactis
strain ML3 were obtained either as a consequence of continuous transfer of the bacteria in broth containing increasing amounts of CM or by selecting for high-level resistant derivatives after mutagenic treatment of the bacteria. Some CM-resistant cells obtained by the first method were also resistant to the homologous bacteriophage. Cells trained to grow in the presence of CM developed resistance to some heterologous attacking phages but not to phage ml
3
. Mutants selected for phage resistance were not resistant to CM. There appear to be two different loci for CM resistance on the bacterial chromosome: the one for high-level resistance is associated with the phage-resistance locus and the other is independent of it. A concentration of CM (280 μg/ml) that was bacteriostatic for ML3 inhibited the intracellular growth of ml
3
phage in strain ML3-CM
r
I, which had been trained to grow in the presence of that CM concentration, despite the fact that cells of this strain were not phage-resistant per se. The drug had no direct virucidal action and did not prevent adsorption to or penetration of phage into the bacterium. Lysogenization did not occur. It is concluded that the block in phage development probably involves inhibition of synthesis of phage components, either involving deoxyribonucleic acid at an early stage or the phage coat protein at a later one.
Dengue Virus Plaque Development in Simian Cell Systems
Authors: Stim Thomas B.
Published: December 2020

Chemical and physical variables influencing the plaquing of all dengue serotypes in two simian cell systems were studied. Calf serum in the nutrient overlay may be replaced by mouse ascitic fluid or bovine plasma albumin when employing the rhesus monkey kidney LLC-MK
2
cell system for plaquing all dengue serotypes. Doubling the serum concentration in the overlay had little effect in modifying dengue types 1, 2, 3, and 4 plaque titers. Newborn agamma, 4-week-old and 8-week-old calf serum gave comparable titers with all dengue virus serotypes. Dengue virus titers, plaque size, and development time were unaffected by sodium bicarbonate concentrations ranging from 1.1 to 4.4 mg/ml of overlay. A twofold increase (0.00332 g%) in the amount of either autoclaved or filtered-sterilized neutral red reduced the dengue 2 virus titer as much as 2.2 logs. An increased Mg
++
and decreased Ca
++
concentration in the overlay medium increased the efficiency of the plaquing system.
Dengue Virus Plaque Development in Simian Cell Systems
Authors: Stim Thomas B.
Published: December 2020

Dengue type 2 virus, strain New Guinea B, plaqued with equal facility and titer under overlays containing six different grades of commercial agar in the LLC-MK
2
cell system. Doubling the agar volume on LLC-MK
2
cell monolayers increased the plaque development time of dengue type 1, strain Hawaii. Storage of agar at 56 C reduced or totally abolished dengue type 4, strain H-241, plaque titer in LLC-MK
2
cells. The influence of six known virus plaque-enhancing compounds on plaque development of all dengue virus serotypes was studied in two continuous simian kidney cell lines, LLC-MK
2
and Vero. In the absence of any chemical additive, plaque development of all dengue serotypes was more rapid (4 to 10 days) in the LLC-MK
2
line than in the Vero line (6 to 13 days). Increased plaque development time of type 1, strain Hawaii, by pancreatin and plaque-size doubling of dengue types 1 and 4 was the only advantage conferred by the addition of six chemical additives in the LLC-MK
2
cell system. Dengue types 1 and 6 failed to plaque in the Vero cell system unless aided by a plaque-enhancing compound; plaques of dengue types 2, 3, 4, and 5 appeared sooner (2 days) and were increased in plaque diameter. The optimal DEAE concentration for plaquing dengue type 1, strain Hawaii, was 100 μg/ml; plaque development either failed at lower concentrations or was inhibited at higher (200 μg/ml) concentrations.
Chemotherapy of Mice Experimentally Infected with
Shigella flexneri
Authors: Das N. K. , Chamberlain R. E.
Published: December 2020

A chronic infection with
Shigella flexneri
2a has been established in mice for the evaluation of compounds for therapeutic potential. Evidence of infection is indicated by prolonged symptomless excretion in the feces and by positive isolation of organisms from different segments of the intestinal tract and from mesenteric lymph nodes. Serum antibody titer reaches a maximum after 9 days of infection and remains at a low level until 32 days postinfection. In this model, five drugs used in human shigellosis were evaluated for efficacy. Ampicillin was found to be the most active followed by oxytetracycline and kanamycin. Neomycin and colistin were the least active in this system.
Ultraviolet Devitalization of Eight Selected Enteric Viruses in Estuarine Water
Authors: Hill William F. , Hamblet Frederick E. , Benton William H. , Akin Elmer W.
Published: December 2020

The effect of ultraviolet (UV) radiation on the devitalization of eight selected enteric viruses suspended in estuarine water was determined. The surviving fractions of each virus were calculated and then plotted against the UV exposure time for purposes of comparison. Analytical assessment of the survival data for each virus consisted of least squares regression analysis for determination of intercepts and slope functions. All data were examined for statistical significance. When the slope function of each virus was compared against the slope function of poliovirus type 1, the analytical findings indicated that poliovirus types 2 and 3, echovirus types 1 and 11, and coxsackievirus A-9 exhibited similar devitalization characteristics in that no statistically significant difference was found (
P
> 0.05). Conversely, the devitalization characteristics of coxsackievirus B-1 and reovirus type 1 were dissimilar from those of poliovirus type 1 in that a statistically significant difference was found between the slope functions (
P
< 0.05). This observed difference in devitalization of coxsackievirus B-1 and reovirus type 1 was attributed primarily to the frequency distribution of single and aggregate virions, the geometric configuration, the size of the aggregates, and the severity of aggregation. The devitalization curve of coxsackievirus B-1 was characteristic of a retardant die-away curve. The devitalization curve of reovirus type 1 was characteristic of a multihittype curve. The calculated devitalization half-life values for poliovirus types 1, 2, and 3; echovirus types 1 and 11; coxsackievirus types A-9 and B-1; and reovirus type 1 were 2.8, 3.1, 2.7, 2.8, 3.2, 3.1, 4.0, 4.0 sec, respectively. These basic data should facilitate an operative extrapolation of the findings to the applied situation. It was concluded that UV can be highly effective and provide a reliable safety factor in treating estuarine water.

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Effects of ω-Amino Acids and Related Compounds on Staphylococcal Infections in Mice: a Combined Prophylactic-Therapeutic Procedure
Authors: Tsuchiya Yoshiki , Tanaka Kinji , Cook Elton S. , Nutini Leo G.
Published: December 2020

By a short-term combined prophylactic-therapeutic procedure, the following compounds were found to be active against staphylococcal infections in Swiss mice: γ-aminobutyric acid, γ-amino-β-hydroxybutyric acid (GABOB), δ-amino-valeric acid (DAVA), ε-aminocaproic acid (EACA),
trans
-4-aminomethylcyclohexanecarboxylic acid (
trans
-AMCHA), taurine, and cysteic acid. Many of these compounds had displayed limited or no activity by a previously used prophylactic procedure. Although DAVA and GABOB were the most potent of the straight-chain ω-amino acids,
trans
-AMCHA displayed the greatest antistaphylococcic activity of the ω-amino acids thus far investigated. Homocarnosine (γ-aminobutyrl histidine, which also was active by the prophylactic procedure) equalled
trans
-AMCHA in activity. Taurine was similar in potency to DAVA, and the activity of cysteic acid approximated that of EACA.
Application of Agglutinins for the Rapid and Accurate Identification of Medically Important
Candida
Species
Authors: Sweet Charles E. , Kaufman Leo
Published: December 2020

Agglutinins have been prepared against the medically important
Candida
species. Crude antisera to the various species demonstrated intense cross-reactions with heterologous yeastlike fungi as well as with many true yeasts. However, carefully monitored adsorptions of selected antisera allowed the production of six factor sera that proved useful in a slide agglutination test. These six sera permitted the rapid and specific identification of
C. guilliermondii, C. krusei, C. parapsilosis
, and
C. pseudotropicalis
. They also allowed the delineation of two groups: (i)
C. albicans
(type A)-
C. tropicalis
and (ii)
C. albicans
(type B)-
C. stellatoidea. C. albicans
type A could be readily distinguished from
C. tropicalis
by its ability to form germ tubes in serum.
C. stellatoidea
could be distinguished from
C. albicans
type B by its predominantly filamentous growth on a nutritionally deficient medium. The medically important
Candida
species could be identified within 24 hr by the combined use of serological and morphological procedures.
Fowl Cholera Immunization in Turkeys
Authors: Davis Richard B. , Brown John , Dawe Donald L. , Foster John W. , Srivastava K. K.
Published: December 2020

Turkeys vaccinated with various experimental vaccines and a commerical bacterin for fowl cholera and surviving an artificially induced epornitic were killed, and their carcasses were examined for wholesomeness. It was evident that, if the “fitness for human consumption” judgement was considered in addition to mortality, efficacy ratings of the various vaccines changed. This suggests that the “fitness for human consumption” factor be considered in future evaluation of biologicals for use in meat-producing birds.
Enhancement by Poly-
d
-Lysine of Poly I: C-Induced Interferon Production in Mice
Authors: Rice J. M. , Turner W. , Chirigos M. A. , Rice N. R.
Published: December 2020

Poly-
d
-lysine of high molecular weight enhances interferon induction in mice by the double-stranded complex of polyinosinic and polycytidylic acids and is superior to diethylaminoethyl-dextran in this respect.
Simple Method for Collection of Samples from a Frozen Food
Authors: Adams D. M. , Busta F. F.
Published: December 2020

The conical end of a plastic funnel can be sterilized and used for aseptic collection, transfer, and distribution of shaving samples drilled from a frozen-food product.

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Cytochemical Electron Microscopic Localization of Esterase Activity in
Lactobacillus casei
Authors: Brown J. P.
Published: December 2020

Enzymes capable of hydrolyzing thiolacetic acid in two strains of
Lactobacillus casei
were localized by the formation of electron-opaque PbS deposits in vivo in the presence of Pb(NO
3
)
2
. By electron microscopy, the deposition of PbS appeared primarily at the plasma membrane and at the outer surface of the cell wall.
Viability Control for Mildew Testing of Materials and Equipment in Tropical Chambers
Authors: Darby Richard T.
Published: December 2020

A method is proposed for indicating proper environmental conditions for fungus development in specification tests of materials in “tropical chambers.”
Bactericidal Activity of a Broad-Spectrum Illumination Source
Authors: Himmelfarab Philip , Scott Arthur , Thayer Philip S.
Published: December 2020

Several hours of exposure to Vita-Lite lamps, which have a unique spectral distribution, give significant killing of cells of
Staphylococcus aureus.
Preparation of Agglutinating Antisera and Fluorescent-Antibody Conjugates Against
Pasteurella tularensis
in Equines
Authors: Green James H. , Bolin Richard C. , Carver Russell K. , Gross Herman , Pigott Nan , Harrell William K.
Published: December 2020

The serological response in burros and horses to the viable LVS strain of
Pasteurella tularensis
was studied. High-titered agglutinating antisera and fluorescent-antibody conjugates were obtained in both groups of animals. Maximum titers were obtained in horses 14 to 21 days after the start of vaccination and in burros 21 to 28 days after the start of vaccination. The use of Woodhour's adjuvants or booster inoculations did not result in increased titers.
Bacteriology of Manganese Nodules
Authors: Trimble R. B. , Ehrlich H. L.
Published: December 2020

Bacillus
29, isolated from a ferromanganese nodule from the Atlantic Ocean, was shown to possess an MnO
2
-reductase system which is induced in the presence of manganous ion. Maximal activity of the enzyme system was induced in about 5 hr in the presence of 4.35 m
m
MnSO
4
and was minimally dependent on the presence of either glucose or peptone and oxygen. Induction of optimal activity required the simultaneous presence of glucose and peptone. At least 30% of maximal activity was induced in 5 hr in the presence of 0.4 μ
m
MnSO
4
. Actinomycin D (5 μg/ml) or chloramphenicol (35 μg/ml), when added to the induction medium, inhibited approximately 90% of MnO
2
-reductase synthesis and incorporation of uracil-
2
-
14
C
or leucine-
1
-
14
C
. Cell-free extracts having MnO
2
-reductase activity were prepared by sonic disruption of cell suspensions of induced
Bacillus
29. Such extracts used glucose metabolism as a source of electrons. They had an average specific activity of 1.15 nmoles of Mn
II
produced per mg of protein per hr at 25 C. They had a temperature optimum of 18 C for reductase activity and retained 50% of their activity at 4 C, the approximate temperature of the natural habitat of the organism. Extracts were stable for several days at 4 C but rapidly lost over 50% of their activity on freezing and thawing. Over 90% of the activity of the extract could be destroyed by heating in a boiling-water bath for 5 min. At a concentration of 1 m
m
, HgCl
2
and atebrine dihydrochloride inhibited MnO
2
-reductase activity by at least 50%, but sodium azide was ineffective. The MnO
2
-reductase activity of induced cells and extracts from them was no greater in the absence of oxygen than in its presence, confirming an earlier observation that MnO
2
and O
2
do not compete as terminal electron acceptors in the respiratory activity of this organism.
Acquired and Native Resistance of
Staphylococcus aureus
to Cephalexin and Other β-Lactam Antibiotics
Authors: Kayser Fritz H. , Benner E. Jack , Hoeprich Paul D.
Published: December 2020

Staphylococcus aureus
cells that are initially susceptible to cephalexin can be induced to acquire intrinsic resistance to cephalexin in comparatively few steps. Concomitantly, resistance to cephalothin, oxacillin, and dicloxacillin increases. By population analysis, there is heteroresistance to cephalexin in some strains of
S. aureus.
Heterogeneity in colonial morphology on prolonged incubation in the presence of subinhibitory concentrations of cephalexin may constitute an expression of such heteroresistance.
Variation of Interferon Production During the Cell Cycle
Authors: Lee Spencer H. S. , Rozee Kenneth R.
Published: December 2020

The capacity of cells to produce interferon has been found to depend on the phase in the cell cycle at which virus infection took place. Monolayer cultures of L cells were synchronized by the double thymidine-block method. Such synchronously growing cultures were used to study the ability of cells to produce interferon when they were infected with ultraviolet-inactivated Newcastle disease virus (UV-NDV) at different phases of the cell cycle. In all instances, interferon was detected early and reached a maximum at about 16 hr after infection. However, the levels of interferon found in medium of cultures infected at early post-deoxyribonucleic acid (DNA) synthetic (G2) and to some extent at late G2 phases of the cell cycle were comparatively lower than those found in cultures infected at the early DNA synthetic (S) phase. There appeared also in these infected growing cultures a transient period when interferon production was apparently delayed. This period corresponded interestingly with the time of mitotic burst. Infection of thymidine- or 1-β-
d
-arabino-furanosylcytosine-inhibited cultures with UV-NDV also led to similar interferon response as that observed in growing cultures infected at early S. However, no transient delay of interferon production was demonstrated in these cultures.
Action of Bacterial Growth on the Sarcoplasmic and Urea-Soluble Proteins from Muscle
Authors: Hasegawa T. , Pearson A. M. , Price J. F. , Lechowich R. V.
Published: December 2020

Comparisons of the starch-gel patterns of uninoculated aseptic control samples from rabbit and pig muscle with similar samples inoculated and incubated with
Clostridium perfringens, Salmonella enteritidis, Achromobacter liquefaciens
, and
Kurthia zopfii
were made. Results indicated that
C. perfringens
caused extensive alteration in the proteins or enzymes, or both, of the sarcoplasmic fraction of porcine muscle, whereas
S. enteritidis
and
S. faecalis
caused complete breakdown of only myoglobin. Neither
A. liquefaciens
nor
K. zopfii
showed any measurable amount of proteolysis in the sarcoplasmic fraction from pig muscle. Although some of the bands in the starch-gel pattern of rabbit muscle decreased in size and intensity of staining, complete proteolysis of any protein fraction was absent for all test organisms. The disc-gel patterns of the 8
m
urea-soluble proteins showed that
C. perfringens
caused extensive proteolysis in pig muscle and a lesser extent of proteolysis in rabbit muscle. None of the other organisms utilized in this study had any measurable effect upon the urea-soluble proteins. In addition, a simple procedure for aseptic isolation of muscle samples for studying meat spoilage is outlined. Results indicate that careful sanitation and cleanliness will give suitable samples for meat spoilage investigations.
Biological Uptake of Phosphorus by Activated Sludge
Authors: Yall Irving , Boughton William H. , Knudsen Richard C. , Sinclair Norval A.
Published: December 2020

The ability of activated sludge to remove phosphates was studied by adding carrier-free
32
P to raw sewage and measuring incorporation of the radioactivity into the cells over a period of time. Radioisotope determinations indicated that 48% of the
32
P radioactivity was removed by 12 hr. However, chemical methods indicated that only 30% of the orthophosphate apparently disappeared from the sewage during this period. Experiments with sludge prelabeled with
32
P indicated that considerable phosphate turnover occurred. The cells released large amounts of radioactivity as they were incorporating fresh phosphates. Starvation in isotonic saline for 18 hr caused the sludge to dump phosphate. When introduced into fresh sewage containing
32
P, the starved sludge removed about 60% of the radioactivity in 6 hr with little phosphate turnover. The ability of sludge to remove
32
P was inhibited approximately 83% by 10
−3
m
2,4-dinitrophenol. This inhibition was at the expense of the cell fraction that contained ribonucleic acid and deoxyribonucleic acid. The sludge cells released orthophosphate when exposed to the chemical agent. Experiments using
45
Ca indicated that calcium phosphate precipitation plays a minor role in phosphate removal under our experimental conditions.
Unusual Fermentative, Gram-Negative Bacilli Isolated from Clinical Specimens
Authors: Gilardi G. L. , Bottone E. , Birnbaum M.
Published: December 2020

Five strains of gram-negative, yellow chromogenic bacilli were recovered from clinical specimens which fit the characteristics of the “
lathyri-herbicola
group” within the genus
Erwinia.
The strains were facultatively anaerobic, fermentative, anaerogenic bacilli with peritrichous flagella which grew at 37 C, reduced nitrate to nitrite, and failed to produce oxidase, pectinase, arginine dihydrolase, and decarboxylases for lysine and ornithine. Aggregations of bacteria (symplasmata) were observed in the syneresis water of slant cultures, and analogous granular aggregates and biconvex, spindle-shaped bodies developed in colonies on plate cultures. Awareness of these characteristics should result in more frequent identification of
Erwinia
species from human sources.
In Vitro Activity of Lincomycin and Spectinomycin Against Serotypes of Avian Mycoplasma
Authors: Hamdy A. H. , Blanchard C. J.
Published: December 2020

Twenty strains of avian mycoplasma, representing 12 serotypes, were tested in vitro for their susceptibility to the action of lincomycin and spectinomycin alone and in combination. They varied in their sensitivity pattern. The ranges of minimal inhibitory concentration were 1 to 20 μg/ml for lincomycin or spectinomycin alone and 0.5/1 to 3/6 μg/ml for the lincomycin and spectinomycin combination. The ranges of minimal lethal concentration were greater with either single antibiotic than with the antibiotic combination. The amount of each antibiotic required to achieve mycoplasmacidal action of the relatively resistant strains was less with the antibiotic combination than with the single antibiotics.
Australia Antigen in a Closed Adult Population Monitored for Serum Glutamic Oxalacetic Transaminase
Authors: Hok K. A. , Nieman R. , Lackey J. O. , Cabasso V. J.
Published: December 2020

A study of the presence of Australia antigen (Au/SH) was conducted over a period of 21 weeks among volunteer plasma donors living in a prison and being monitored for serum glutamic oxalacetic transaminase (SGOT). A good correlation was observed between the level of SGOT and presence of Au/SH, the latter being present in 33% of donors with SGOT values higher than 101 Karmen units and in 12% of those with SGOT values of 41 to 100 units. Furthermore, none of the 87 donors with all SGOT values below 40 was found positive for Au/SH. It should be noted, however, that single specimens only were tested from 72 of the 87 individuals. Au/SH was detected with equivalent efficiency by both agar gel precipitation and complement fixation procedures. Implications of these findings in the prognostication of hepatitis carrier state are discussed.
Homogeneous Bacterial Aerosols Produced with a Spinning-Disc Generator
Authors: Harstad J. Bruce , Filler Melvin E. , Hushen William T. , Decker Herbert M.
Published: December 2020

Aerosols composed of viable particles of a uniform size were produced with a commercial spinning-disc generator from aqueous suspensions of
Bacillus subtilis
var.
niger
spores containing various amounts of an inert material, dextran, to regulate aerosol particle size. Aerosols composed of single naked spores having an equivalent spherical diameter of 0.87 μm were produced from spore suspensions without dextran, whereas aerosols produced from suspensions containing 0.001, 0.01, 0.1, and 1% dextran had median diameters of 0.90, 1.04, 1.80, and 3.62 μm, respectively. Such aerosols, both homogeneous and viable, would be useful for calibrating air sampling devices, evaluating air filter systems, or for employment wherever aerosol behavior may be size-dependent.
Isolation of
Vibrio parahaemolyticus
from the Processed Meat of Chesapeake Bay Blue Crabs
Authors: Fishbein Morris , Mehlman Ira J. , Pitcher Judy
Published: December 2020

A method for the recovery of
Vibrio parahaemolyticus
from seafoods is described. By this procedure, a total of 56 biochemically positive cultures of
V. parahaemolyticus
were recovered from market samples of Chesapeake Bay processed blue crab (cooked, picked, packed, and refrigerated meat). All of the isolates were tested serologically, and 22 strains were serotyped according to the schema of Sakazaki as follows: K3, K5, K28, K31, K36, K37, K39, K43, and K44. These results indicate the broad distribution of these specific serotypes in a seafood harvested from the Chesapeake Bay.
Occurrence of
Vibrio parahaemolyticus
and Related Hemolytic Vibrios in Marine Environments of Washington State
Authors: Baross J. , Liston J.
Published: December 2020

Samples of sediment, water, and fauna were tested for the presence of
Vibrio parahaemolyticus
and the related biotype
V. alginolyticus
. Altogether, 379 samples were analyzed quantitatively by using a starch-agar medium. Invertebrate and sediment samples were invariably positive for
V. parahaemolyticus
, whereas water samples were quite variable. Samples of the Pacific oyster (
Crassostrea gigas
), obtained on a regular basis for 26 months from a single environment, showed a close correlation between total numbers of mesophilic vibrios and the overlying water temperature; the seasonal counts of oysters ranged from less than 10 to greater than 100,000 per g. Ecological implications and possible pathogenicity of these vibrios are discussed.
Influence of Incubation Temperature and Sodium Heptadecyl Sulfate (Tergitol No. 7) on the Isolation of Salmonellae from Pork Sausage
Authors: Morris George K. , Dunn Carolyn G.
Published: December 2020

Cultures of 68 samples of fresh pork sausage purchased locally were incubated at 37 and 43 C, with and without Tergitol No. 7 (sodium heptadecyl sulfate) added to the tetrathionate-Brilliant Green enrichment broth. The results indicated an advantage in incubating the tetrathionate broth at 43 C rather than 37 C in attempting to isolate salmonellae from pork sausage. Without Tergitol, more samples were positive at 43 C than at 37 C, but with Tergitol there was no difference. The higher temperature suppressed the competing gram-negative bacteria and permitted
Salmonella
to grow in relatively pure culture, thus providing an advantage for isolating and identifying the organisms. Tergitol dispersed and emulsified the fat which improved the isolation of
Salmonella
when the cultures were incubated at 37 C but not at 43 C. Brilliant Green-sulfadiazine agar was superior to bismuth sulfite agar for isolating salmonellae from tetrathionate broth cultures of fresh pork sausage.
Mycotoxin from a Blue-Eye Mold of Corn
Authors: Kurtzman C. P. , Ciegler A.
Published: December 2020

High-moisture yellow dent corn became heavily molded by
Penicillium martensii
after storage for 6 months at 1 C. Mice ingesting corn molded by
P. martensii
died within a few days. The toxin was isolated and identified as penicillic acid. Large quantities of the toxin accumulated over a 3-month period on artificially inoculated corn incubated at temperatures between 1 and 15 C. At higher temperatures, the toxin disappeared within 45 days.
Preservation of
Borrelia kansas
and
Plasmodium berghei
Authors: Allen Emma G.
Published: December 2020

Borrelia kansas
and
Plasmodium berghei
have been stored after slow freezing in thioglycollate-glycerol medium for a 6-month period. During this time, 75% or more of the
Borrelia
remained motile, many intracellular malarial parasites exhibited amoeboid movement, and the growth pattern of both organisms in mice remained unchanged.
Presumptive Identification of Group D Streptococci: the Bile-Esculin Test
Authors: Facklam Richard R. , Moody Max D.
Published: December 2020

Six tests commonly used for the presumptive identification of group D streptococci were evaluated. Strains tested included 282 group D streptococci and 366 non-group D. Ratios of percentages of group D to non-group D strains which gave positive reactions for each test are as follows: bile-esculin, 100:2; salt tolerance, 88:24; heat tolerance, 100:80; SF broth, 86:1; KF broth, 99:40; and methylene blue milk reduction, 90:17. These data indicate that the bile-esculin test provided a reliable means of identifying group D streptococci and differentiating them from non-group D streptococci. Methodology for reading and interpreting positive reactions and time of incubation of the bile-esculin medium was defined. Evidence of the need for standardization of salt and heat-tolerance tests was obtained.
Spectrophotometric Methods for Monitoring the Microbial Transformation of Steroids
Authors: Ivashkiv Eugene
Published: December 2020

A method has been devised for the determination of 9α-fluorohydrocortisone and 9α-fluoro-16α-hydroxyhydrocortisone in fermentation broths. The method involves extraction of the two steroids from the broth with ethyl acetate, separation through the formation of the water-soluble borate complex of the vicinally hydroxylated steroid, and estimation of each steroid spectrophotometrically.
Production of Nucleic Acid-Related Substances by Fermentation Processes
Authors: Furuya Akira , Abe Shigeo , Kinoshita Shukuo
Published: December 2020

Inosine-producing cultures were found among mutants resistant to 6-mercaptoguanine (6MG) derived from a 5′-inosinic acid (IMP)-producing strain, KY 13102, of
Brevibacterium ammoniagenes.
Inosine-producing ability was very frequent among the mutants resistant to a low concentration (10 to 50 μg/ml) of 6MG. The accumulation of inosine by strain KY 13714 was stimulated by a low concentration of adenine (25 mg/liter) but was depressed by high levels of adenine. The accumulation by strain KY 13714 was not inhibited by manganese ion but instead was stimulated by its excess, in contrast to IMP accumulation by KY 13102. Addition of hypoxanthine at an early stage of cultivation accelerated inosine accumulation. Furthermore, on addition of hypoxanthine and of a surface-activating agent after 48 hr of cultivation, the simultaneous accumulation of IMP and inosine was observed. A 9.3-mg amount of inosine per ml accumulated after 4 days of cultivation at 30 C. The inosine-producing mutant did not differ from the IMP-producing strain either in 5′ purine nucleotide degradation or in IMP formation from hypoxanthine. However, it was found to be completely devoid of purine nucleoside-degrading activity. The conversion of IMP accumulation to inosine can be explained by the lack of nucleosidedegrading activity. The relationship between deficiency of nucleoside-degrading activity and resistance to low levels of 6MG is discussed, and a new mechanism for 6MG resistance is presented.
New Method for Detecting Bacteriocin Production
Authors: Kékessy D. A. , Piguet J. D.
Published: December 2020

Bacteriocin production can be easily detected by using both sides of the agar contained in a standard petri dish.
Effect of Storage of Mueller-Hinton Agar Plates on Zone Sizes for Antimicrobial Testing
Authors: Dewees Linda B. , Poupard James A. , Morton Harry E.
Published: December 2020

The length of time Mueller-Hinton agar plates can be stored at 4 C without affecting the size of zones of inhibition in susceptibility testing by the Bauer-Kirby method was studied. It was found that these plates can be stored for 3 weeks at 4 C without an appreciable affect on zone sizes. Storage of plates in sealed plastic bags did not alter the results significantly. The findings indicate that commercially prepared Mueller-Hinton agar plates, which may be several days old when received at the laboratory, are suitable for use in routine susceptibility tests by the Bauer-Kirby method.
Identification of
Enterobacteriaceae
in the Clinical Microbiology Laboratory
Authors: Traub Walter H. , Raymond Ella A. , Linehan Josephine
Published: December 2020

A total of 5,137 enterobacterial clinical isolates were examined with three series of biochemical tests. The data were analyzed with respect to the use of economical and practical procedures for the accurate identification of lactose-fermenting and -nonfermenting
Enterobacteriaceae
within 24 hr after isolation.
Agar Overlay Plaquing Technique for
Pseudomonas aeruginosa
in HeLa Monolayers
Authors: Wexler Seymour , Ludovici Peter P. , Moore Marion L.
Published: December 2020

The solid agar overlay procedure used for viral plaquing was adapted to the study of
Pseudomonas aeruginosa
plaques in HeLa monolayers. After adsorption of the organism to the HeLa monolayers, an overlay consisting of 10% newborn calf serum (NBCS), 90% Eagles basal medium (EBM), and 1.5% agar containing neutral red was added. Plaques developed after 24 hr of incubation at 37 C which were indistinguishable from viral lesions. Optimal conditions for plaques included: serum in the adsorption fluid as well as the overlay medium; 1-hr adsorption time; healthy HeLa monolayers; and the presence of EBM. The formation of plaques instead of colonies in agar was due to the inhibitory effect of NBCS or EBM. By omitting both of these components from the overlay, colonies appeared in place of plaques. Adult bovine serum acted in a similar bacterial colony-suppressing fashion, but fetal or agamma calf serum did not. Furthermore, NBCS or adult bovine serum when incorporated in the overlay medium instead of fetal or agamma calf serum displayed a plaque-suppressing effect by reducing the number and size of plaques formed. The findings lend further evidence to support the hypothesis that
P. aeruginosa
may produce plaques from a protected intracellular site within HeLa cells.
Isolation of L-Forms in a Clinical Microbiology Laboratory
Authors: Swierczewski John A. , Reyes Perla
Published: December 2020

Previous studies have demonstrated that L-forms of bacteria may play a role in persistent, chronic, or recurrent urinary-tract infections. A 2-year program was initiated to determine the feasibility of culturing for L-forms on a routine basis, and to determine the effectiveness of such a program. In relation to the total number of specimens, few L-forms were actually isolated. In comparison with the amount of equipment and technician time required, the return was negligible; only 0.5% of all urine specimens were positive for L-forms. An increase to only 1.2% was noted when culturing for L-forms was limited to patients with a diagnosis of bacteriuria or pyelonephritis. It is recommended that this technique be reserved for those patients with a long history of recurrent urinary-tract infections, after other attempts to cure the patient have met with failure.
Comparison of Methods for Coccidioidomycosis Complement Fixation
Authors: Huppert Milton , Chitjian Patricia A. , Gross Alan J.
Published: December 2020

A Laboratory Branch Task Force of the National Communicable Disease Center has proposed a standardized complement fixation procedure (LBCF) and an adaptation of this to microtitration techniques (MT) as uniform methods for performing complement fixation (CF) tests. A common procedure should make CF results from one laboratory more comparable to another. In addition, it would be preferable if the common procedure reproduced the titer levels of a testing procedure which is to be replaced, particularly when valid clinical interpretations have been derived from the latter. Replicated sets of sera were tested by the LBCF, MT, and the standard Smith CF procedure for coccidioidomycosis. Results with all three procedures were highly reproducible within an acceptable one-tube variation of a twofold dilution series, but the frequency of one-tube variations was greater with the MT method than with the other two. There was no statistical difference in the titers obtained with the Smith and LBCF procedures, but there was a significant difference when the MT results were compared to those with the Smith method. The LBCF method should be acceptable as a standardized and uniform CF procedure for coccidioidomycosis, subject to comparative testing between different laboratories.
Evaluation of Liquid Nitrogen Storage for Preservation of Group A Streptococcal M Protein-Sensitized Sheep Red Blood Cells
Authors: Mathews James H. , Zimmerman Robert A.
Published: December 2020

Streptococcal M protein-sensitized sheep red blood cells stored in liquid nitrogen showed insignificant change in titer when tested against homologous antisera over a 6-month period. This method eliminates much of the preparation time required for the passive hemagglutination procedure and increases the reproducibility of the test.
Microneutralization Test for the Determination of Mumps Antibody in Vero Cells
Authors: Kenny M. T. , Albright K. L. , Sanderson R. P.
Published: December 2020

A sensitive and reproducible test for the determination of mumps serum-neutralizing antibody with Vero cells grown in disposable plastic microtiter plates is described. Serum end point titers obtained by this method showed excellent correlation with those obtained by the primary chick embryo tissue culture-hemadsorption tube test.
Viral Aggregation Resulting in the Failure to Correctly Identify an Unknown Rhinovirus
Authors: Gwaltney Jack M. , Calhoun Anne M.
Published: December 2020

A seed lot of strain SF 1684 of rhinovirus type 2 prepared in human embryonic lung cells (WI-38) contained aggregates which interfered with its neutralization by homotypic or homologous antisera. The same virus showed no evidence of aggregation at five other passage levels studied. Virus in the seed lot was not identified correctly, and the titer of homologous antiserum was mistakenly considered to be low as a result of neutralization tests conducted with the aggregated virus. Filtration and a more easily effected treatment with sodium deoxycholate (1%) disaggregated the virus and restored its susceptibility to neutralization by homologous and homotypic antiserum.
Enumeration of
Byssochlamys
and Other Heat-Resistant Molds
Authors: Splittstoesser D. F. , Kuss F. R. , Harrison Wanda
Published: December 2020

Methods for the detection of low numbers of heat-resistant molds on fruits were studied by using cultures of
Byssochlamys
and a number of unidentified mold isolates. Ascospore dormancy had a marked effect on viable recoveries, and the medium in which ascospores were heated influenced activation rates. Best results were obtained when fruit homogenates were heated for 60 min at 70 C in Concord grape juice, followed by culturing on acidified Potato Dextrose Agar.
Development of Four Arboviruses in Mice and Application to Rapid Test Procedures
Authors: Calisher Charles H. , Maness Kathryn S. C.
Published: December 2020

Mice were inoculated with St. Louis encephalitis (SLE), Flanders (FLAN), California (CE), or Tensaw (TEN) viruses. At fixed intervals after inoculation, brains from these mice were collected and assayed for infective virus and complement-fixing, hemagglutinating, and precipitating antigens. Detectability of these antigens was correlated with the appearance of signs of illness in the mice. Infective virus appeared 64, 48, 48, and 40 hr before signs of illness and 90, 86, 64, and 56 hr before death in mice inoculated with SLE, FLAN, CE, and TEN viruses, respectively. Diagnostic antigens were also detected well before signs of illness appeared. These findings were applied to the isolation of viruses from field-collected specimens. It was shown that by harvesting tissues at appropriate intervals these viruses could be detected and identified more rapidly than by conventional techniques with mice.
Bacteriophage Active Against the Lactic Acid Beverage-Producing Bacterium
Lactobacillus casei
Authors: Watanabe K. , Takesue S. , Jin-Nai K. , Yoshikawa T.
Published: December 2020

A virulent bacteriophage which causes a decrease in acid production during fermentation of a lactic acid beverage named Yakult with
Lactobacillus casei
was isolated from the abnormal fermentation tank and named PL-1.
L. casei
S strain was the exclusive host cell among 18 lactic acid bacteria tested. The plaque was round with an average diameter of about 0.5 mm. It exhibited serological cross-reaction with previously isolated J1 phage. Under an electron microscope, the phage had a spermatozoon shape, with an icosahedral head (63 nm) and a long tail (12.5 by 275 nm) with about 55 striae. The free phage particles were stable at
p
H 5 to 8. The phage was quite sensitive to ultraviolet irradiation or to heating (60 C, 5 min), and the host was more sensitive than the phage to these treatments. Many kinds of antimicrobial chemicals were also phagocidal. Calcium ion (5 m
m
) was specifically essential for the phage growth cycle. A one-step growth experiment under optimum conditions (37 C and
p
H 6.0) showed that the eclipse period was about 75 min, that the latent period was 100 min after the phage infection, and that the average burst size was about 200. The possibility of arresting phage development in lactic acid fermentation is discussed.