bluuebunny/crossref_metadata_2025 huggingface dataset:
Involvement of Phosphoenolpyruvate in Lactose Utilization by Group N Streptococci
Authors: McKay L. L. , Walter L. A. , Sandine W. E. , Elliker P. R.
Published: January 2020

The effect of sodium fluoride on lactose metabolism and
o
-nitrophenyl-β-
d
-galactopyranoside (ONPG) hydrolysis by
Streptococcus lactis
strains 7962 and C
2
F suggested that different mechanisms of lactose utilization existed in the two strains. Sodium fluoride prevented lactose utilization and ONPG hydrolysis by whole cells of
S. lactis
C
2
F but had no effect on
S. lactis
7962. Although hydrolysis of ONPG by toluene-treated cells of
S. lactis
7962 occurred without addition of phospho-enolpyruvate (PEP), toluene-treated cells of
S. lactis
C
2
F required the presence of this cofactor. Concentrated cell extracts of
S. lactis
C
2
F hydrolyzed ONPG; this hydrolysis was inhibited by NaF, but the addition of PEP, in the presence of NaF, restored maximal activity. Addition of acetyl-phosphate, carbamyl-phosphate, adenosine-5′-triphosphate, guanosine-5′-triphosphate, or uridine-5′-triphosphate did not stimulate activity. The presence of cofactors did not stimulate and NaF did not inhibit the hydrolysis in extracts of
S. lactis
7962. To confirm the operation of two mechanisms,
S. lactis
7962 was shown to hydrolyze lactose to glucose and galactose, whereas
S. lactis
C
2
F was unable to split the disaccharide. In addition, whole cells of
S. lactis
C
2
F rapidly accumulated a phosphorylated derivative of thiomethyl-β-
d
-galactoside (TMG) which behaved chromatographically and electrophoretically like TMG-PO
4
. Unexpectedly,
S. lactis
7962 also accumulated a TMG derivative, although the rate was extremely low. These data indicate that different mechanisms of lactose utilization exist in the two strains, with a phosphorylation step dependent on PEP involved in
S. lactis
C
2
F.
Polyuridylic Acid-directed Phenylalanine Incorporation in Minicell Extracts
Authors: Fralick J. A. , Fisher W. D. , Adler H. I.
Published: January 2020

Cell-free extracts of miniature
Escherichia coli
cells deficient in deoxyribonucleic acid (DNA) and DNA-dependent ribonucleic acid polymerase have been shown to be capable of polyuridylic acid-directed [
14
C]phenylalanine incorporation.
Oxidation of Isomaltose by
Pseudomonas taetrolens
Authors: Sternberg M. , Lockwood L. B.
Published: January 2020

Pseudomonas taetrolens
NRRL B14 oxidized isomaltose without hydrolysis of the 1–6 glycosidic linkage. The resulting isomaltobionic acid was identified by chromatographic studies of acid hydrolysates and reconversion to isomaltose.
Feedback Inhibition of Lysine Biosynthesis in Yeast
Authors: Tucci Anthony F.
Published: January 2020

The pathway for the biosynthesis of lysine is feedback-inhibited by lysine in growing yeast.
Salmonella
Suppression by Known Populations of Bacteria in Flies
Authors: Greenberg Bernard
Published: January 2020

Survivorship of
Salmonella typhimurium, Streptococcus faecalis, Proteus mirabilis
, and
Pseudomonas aeruginosa
was studied in dibiotic and tribiotic interactions in vitro and in various regions of the digestive tract of the blow fly,
Calliphora vicina
. In dibiotic interactions,
Salmonella typhimurium
dominated
Streptococcus faecalis
and was dominated by
P. mirabilis
, but in neither case was it eliminated from the larval gut. In tribiotic interactions, there was synergic suppression and a definite trend toward elimination of
Salmonella typhimurium
from the gut. This trend approaches but does not match the total exclusion of
S. typhimurium
from the gut of maggots with a normal flora. Bacterial survival in the gut of the fly is discussed in relation to doubling time, sweep-out rate of the maggot and prepupal gut, and the midgut bactericide.
Properties and Characteristics of a Bacteriocin from
Serratia marcescens
Authors: Foulds John D. , Shemin David
Published: January 2020

A strain of
Serratia marcescens
was found to produce a bacteriocin that inhibits the growth of certain
Escherichia coli
strains. This inhibition was bacteriocidal rather than bacteriostatic and was not caused by a bacteriophage. Whereas the bacteriocin was inactive on the 7
Serratia
strains tested, it killed 11 of the 20
E. coli
strains tested for sensitivity. A relationship of the bacteriocin to a possible colicin cannot as yet be excluded, although
E. coli
mutants resistant to 1 or 2 of 15 different colicins remained sensitive to the bacteriocin. The bacteriocidal effect by the bacteriocin could be interrupted in a substantial fraction of the treated cell population by the addition of trypsin. The synthesis of the bacteriocin was inducible by ultraviolet light or by starvation for thymidine. Both procedures led to a similar increase in maximum bacteriocin titer relative to noninduced cultures.
Concomitant Synthesis of Bacteriocin and Bacteriocin Inactivator from
Serratia marcescens
Authors: Foulds John D. , Shemin David
Published: January 2020

We have found that
Serratia marcescens
strain P & S is bacteriocinogenic. However, the phenotypic expression of bacteriocin activity depends upon the temperature at which the cells are grown. When the organism is grown at 30 to 37 C, no bacteriocin activity can be demonstrated, whereas when it is grown at 39 C bacteriocin activity is readily observed. It appears that the P & S strain concomitantly synthesizes a bacteriocin and a substance which not only can inactivate the bacteriocin but also has a high activation energy for inactivation. This inactivator readily loses its activity when heated at 39 C for 1 hr. Two mutants were isolated from the P & S strain which can produce active bacteriocin when grown at temperatures from 30 to 39 C. It is significant that these mutants have considerably less bacteriocin inactivator. The data suggest that the inactivator is an extracellular protease. The ability of one of these mutants, JF58-12, to produce active bacteriocin at temperatures between 30 and 39 C is a stable property, whereas in the other mutant, JF48W, this property is unstable. JF48W was selected from the P & S strain in two steps: first a streptomycin-resistant variant (strain A-10) was isolated and from this mutant a strain (JF48W) was isolated which not only synthesized little of the inactivator but also did not synthesize the red pigmnet prodigiosin. This latter pleiotropic mutant appears to revert in one step to a phenotype similar to the P & S strain, since it is streptomycin-sensitive and produces prodigiosin and normal amounts of inactivator and the demonstration of bacteriocin activity is temperature-dependent.
Genetic Homologies Among
Streptomyces violaceoruber
Strains
Authors: Monson A. M. , Bradley S. G. , Enquist L. W. , Cruces Griselda
Published: January 2020

Most of the genetic studies on streptomycetes have been done with cultures erroneously designated as
Streptomyces coelicolor
. To determine whether these cultures are genetically homologous with the
S. violaceoruber
nominifer, their deoxyribonucleic acids (DNA) were analyzed, and selected pairs of mutants were crossed. The four cultures used in genetic studies, and called
S. coelicolor
in the literature, were found to constitute a genospecies, based upon DNA hybridization and recombination tests. In addition, DNA from
Actinopycnidium caeruleum
formed extensive duplexes with
S. violaceoruber
DNA.
S. violaceoruber
cultures and
A. caeruleum
were distinctly different from the
S. coelicolor
nominifer.
Nitrate Reductase Complex of
Escherichia coli
K-12: Participation of Specific Formate Dehydrogenase and Cytochrome
b
1
Components in Nitrate Reduction
Authors: Ruiz-Herrera José , DeMoss J. A.
Published: January 2020

The participation of distinct formate dehydrogenases and cytochrome components in nitrate reduction by
Escherichia coli
was studied. The formate dehydrogenase activity present in extracts prepared from nitrate-induced cells of strain HfrH was active with various electron acceptors, including methylene blue, phenazine methosulfate, and benzyl viologen. Certain mutants which are unable to reduce nitrate had low or undetectable levels of formate dehydrogenase activity assayed with methylene blue or phenazine methosulfate as electron acceptor. Of nine such mutants, five produced gas when grown anaerobically without nitrate and possessed a benzyl viologen-linked formate dehydrogenase activity, suggesting that distinct formate dehydrogenases participate in the nitrate reductase and formic hydrogenlyase systems. The other four mutants formed little gas when grown anaerobically in the absence of nitrate and lacked the benzyl viologen-linked formate dehydrogenase as well as the methylene blue or phenazine methosulfate-linked activity. The cytochrome
b
1
present in nitrate-induced cells was distinguished by its spectral properties and its genetic control from the major cytochrome
b
1
components of aerobic cells and of cells grown anaerobically in the absence of nitrate. The nitrate-specific cytochrome
b
1
was completely and rapidly reduced by 1 m
m
formate but was not reduced by 1 m
m
reduced nicotinamide adenine dinucleotide; ascorbate reduced only part of the cytochrome
b
1
which was reduced by formate. When nitrate was added, the formate-reduced cytochrome
b
1
was oxidized with biphasic kinetics, but the ascorbate-reduced cytochrome
b
1
was oxidized with monophasic kinetics. The inhibitory effects of
n
-heptyl hydroxyquinoline-
N
-oxide on the oxidation of cytochrome
b
1
by nitrate provided evidence that the nitrate-specific cytochrome is composed of two components which have different redox potentials but identical spectral properties. We conclude from these studies that nitrate reduction in
E. coli
is mediated by the sequential operation of a specific formate dehydrogenase, two specific cytochrome
b
1
components, and nitrate reductase.
Regulation of Chromosome Replication in
Bacillus subtilis:
Effects of Amino Acid Starvation in Strain 168
Authors: Copeland James C.
Published: January 2020

Regulation of chromosome replication in
Bacillus subtilis
strain 168, in response to starvation for an essential amino acid, was found to differ from that reported for
Escherichia coli
. Not all replication points stop at the terminus during amino acid starvation. There is some evidence, however, to indicate that preferred stopping sites might exist. Initiation at the origin can occur in the absence of total protein synthesis as well as when the deoxyribonucleic acid (DNA)- mass ratio is unbalanced. DNA synthesis appears to be controlled independently of the initiation event by a second regulatory circuit, that may utilize the DNA-mass ratio. Once initiated, chromosome replication does not always go to completion in an uninterrupted sequence.
Origin and Sequence of Chromosome Replication in
Neisseria meningitidis
: Influence of a Genetic Factor Determining Competence
Authors: Jyssum Kaare
Published: January 2020

Chromosome replication in
Neisseria meningitidis
was examined by enumerating mutants induced by nitrosoguanidine during synchronous replication after release from prolonged chloramphenicol inhibition. Clear maxima of mutagenesis were observed at certain times. These times were different for seven individual markers. At a definite time after the first maximum, there was a second one. The intervals between successive maxima were identical for all markers in each experiment. This permitted the construction of replication maps which were in general agreement with mapping based on marker frequency analysis by use of a transformation system. Comparison of replication in genetically competent and genetically incompetent variants substantiated the previous assumption that the change from genetic competence to genetic incompetence in this strain results in a change in the replication origin as well as in the direction of replication.
“Self-Feeding” Strain of
Salmonella typhimurium
with a Mutation in the
trpB
Gene and Nutritional Requirements of
trpA
Gene Mutants
Authors: Stuttard Colin , Dawson G. W. P.
Published: January 2020

An indole-requiring (Ind
−
) mutant of
Salmonella typhimurium
, isolated from a culture of a leaky
trpA
mutant, was genetically analyzed by P22-mediated transduction. The mutation site giving the Ind
−
phenotype was shown to be in
trpB
, the second gene of the
trp
operon. A second mutation at this site resulted in change of nutritional requirement from indole to anthranilic acid (Anth
−
). This phenotype is normally associated with mutations in the first
trp
gene,
trpA
. However, the Anth
−
mutant also excreted anthranilic acid and showed “self-feeding” on unsupplemented media. Of two possible explanations for this aberrant phenotype, the first, that the
trpB
mutations may be in the “unusual” region, was dismissed on genetic evidence and on the biochemical evidence that an active anthranilate synthetase (AS) is produced. The alternative explanation, that the affected enzymatic activity, phosphoribosyl transferase, is unstable in vivo, but its AS component 2 activity is stable, is considered more probable.
Regulation of the Biosynthesis of Amino Acids of the Aspartate Family in Coliform Bacteria and Pseudomonads
Authors: Cohen G. N. , Stanier R. Y. , Bras Gisele Le
Published: January 2020

The control of aspartokinase and homoserine dehydrogenase activities was compared in aerobic and fermentative pseudomonads (generaPseudomonasandAeromonas), and in coliform bacteria representative of the principal genera of theEnterobacteriaceae. Isofunctional aspartokinases subject to independent end-product control occur in theEnterobacteriaceaeand inAeromonas. InPseudomonas, there appears to be a single aspartokinase, subject to concerted feedback inhibition by lysine and threonine. Within this genus, the sensitivity of aspartokinase to the single allosteric inhibitors varies considerably: the aspartokinase of the acidovorans group is little affected by the single inhibitors, whereas that of the fluorescent group is severely inhibited by either amino acid at high concentration. In all bacteria examined, homoserine dehydrogenase activity is inhibited by threonine; inhibition is more severe in aerobic pseudomonads than in the other groups. In most of the bacteria examined, either nicotinamide adenine dinucleotide (NAD) or nicotinamide adenine dinucleotide phosphate can serve as a cofactor for this enzyme, though the relative activity with the two pyridine nucleotides varies widely. Aerobic pseudomonads of the acidovorans group contain a homoserine dehydrogenase that is absolutely specific for NAD. The taxonomic implications of these findings are discussed.
Unlinking of Cell Division from Deoxyribonucleic Acid Replication in a Temperature-sensitive Deoxyribonucleic Acid Synthesis Mutant of
Escherichia coli
Authors: Inouye Masayori
Published: January 2020

A new type of temperature-sensitive deoxyribonucleic acid (DNA) synthesis mutant, which can divide without a completion of DNA replication, was isolated from a thymidine-requiring
Escherichia coli
strain by means of photo-bromouracil selection after nitrosoguanidine mutagenesis. In this mutant, in spite of the fact that DNA synthesis stopped immediately after the temperature shift from 30 to 41 C, cells could continue to divide, though at a reduced rate. This cell division without DNA synthesis at 41 C is further supported by the following results. (i) Cell division took place at high temperature without addition of thymidine but not at all at 30 C. The parent strain of the mutant did not divide at 41 C without thymidine. (ii) Smaller cells isolated from the culture grown at 41 C did not contain DNA. This was shown by chemical analysis of the smaller cells and on electron micrographs. Ability of cells to divide was examined according to sizes of cells. By using the culture at 30 C, cells of various sizes were separated by means of sucrose-density gradient centrifugation. It was found that all cell fractions, including the smallest one, could divide at high temperature. These results suggest that in this mutant the completion of DNA replication is not required for triggering cell division at high temperature. Heat sensitivity of a factor which links cell division with DNA replication appears to be responsible. Some possible mechanisms of the coordination between cell division and DNA replication are discussed.
Comparison of the Pathogenicity for Mice of
Mycobacterium fortuitum
and
Mycobacterium abscessus
Authors: Saito Hajime , Tasaka Hiromichi
Published: January 2020

The pathogenicity for mice of 12 strains of
Mycobacterium abscessus
was compared with that for 8 strains of
M. fortuitum
. Both species caused lesions in kidneys and produced “spinning disease” resulting from inner ear infections. No major differences in pathogenicity of these two species were demonstrated. Strain to strain variation was marked, especially with
M. abscessus
. For example, 1.6 × 10
6
organisms of strain 11188 of
M. abscessus
produced death in four of five animals within 42 days, whereas strain 380 of
M. abscessus
failed to produce any deaths within 42 days. In the case of
M. fortuitum
, the greatest mortality observed was one of five animals, yet the incidence of spinning disease and kidney disease occurred earlier postinfection than in mice infected with
M. abscessus
. Histologically, abscess formation by a strain of
M. abscessus
was greater than by a strain of
M. fortuitum
, but this difference cannot be interpreted as a species difference.
Ultrastructure of
Nocardia
Cell Growth and Development on Defined and Complex Agar Media
Authors: Beaman B. L. , Shankel D. M.
Published: January 2020

The cell growth of
Nocardia
strain 721-A on Brain Heart Infusion Agar (BHIA), nutrient agar, and chemically defined agar media was studied by light and electron microscopy. Light microscopy revealed a change in cell morphology induced by growth on BHIA. Electron microscopy demonstrated a concurrent change in intracellular complexity. On BHIA, the cells became bulbous and developed irregularly branched filaments which fragmented by multiple and random septation. These fragments appeared to undergo a secondary stage of development similar to that described for
Arthrobacter
. Cells grown on defined or nutrient agar did not become bulbous and lacked the unusual complexity found in cells grown on BHIA. Intracytoplasmic membranes were altered by the nutritional state of the cell and changed during cell development.
Effect of Different Nitrogen Sources on the Cellular Form of
Trigonopsis variabilis
Authors: Šašek Václav , Becker George E.
Published: January 2020

Triangular cells are formed during early logarithmic growth of
Trigonopsis variabilis
. Good triangularity is obtained with methionine, proline, hydroxyproline, or alanine as a nitrogen source.
Mode of Nicotinamide Adenine Dinucleotide Utilization by
Escherichia coli
Authors: Gholson R. K. , Tritz Gerald J. , Matney Thomas S. , Andreoli A. J.
Published: January 2020

Exogenous nicotinamide adenine dinucleotide is not utilized per se by
Escherichia coli
, but is converted to nicotinamide and thence to nicotinamide adenine dinucleotide via nicotinate.
Estradiol-induced Wasting Syndrome in Conventionally Reared and Germ-free Mice
Authors: Hatch George G. , Reed Norman D.
Published: January 2020

The pathogenesis of the estradiol-induced wasting syndrome is complex and cannot be explained solely by immunological impairment and subsequent infection.
Adenosine Triphosphate Inhibition of Yeast Trehalase
Authors: Panek Anita D.
Published: January 2020

Yeast trehalase has been found to be inhibited non-competitively by adenosine triphosphate. Such a biological control could explain the accumulation of trehalose during the stationary phase of the growth curve.
Mode of Action of Colicin A
Authors: de Zwaig Rosa Nagel
Published: January 2020

Colicin A acting on sensitive cells of
Escherichia coli
inhibits a number of energy-requiring cellular functions. It appears to act similarly to colicins E1 and K.
Cellular elongation under the influence of antibacterial agents: way to differentiate coccobacilli from cocci
Authors: Catlin B W
Published: January 2020

Representatives of Moraxella, Acinetobacter, and various other groups of short, gram-negative bacilli are readily distinguished from Neisseria by microscopic observation of filaments produced by the rods during growth in the presence of low concentrations of penicillins or sulfadiazine. Wet mounts of bacteria from routine antibiotic susceptibility test cultures are satisfactory for examination of morphology.
Isolation and Characterization of a Lactose-Positive Strain of
Proteus morganii
Authors: Tierno Philip M. , Steinberg Philip
Published: January 2020

The characterization of a lactose-positive
Proteus morganii
is presented. The increased incidence of such atypical microorganisms emphasizes the need for a thorough examination of
Escherichia coli
-like colonies by clinical microbiologists.
Influence of oxygen and culture media on maintenance of whole hamster trachea organ cultures and replication of Sendai virus
Authors: Schiff L J , Shefner A M
Published: January 2020

Effects of various oxygen concentrations and culture media on the maintenance of 4-day-old hamster trachea organ cultures and the yield of Sendai virus were studied. The basic media used were Eagle minimal essential medium, medium 199, and CMRL 1066 supplemented with glutamine and antibiotics and buffered with NaHCO3 or N-2-hydroxyethyl-piperazine-N'-2'-ethanesulfonic acid (HEPES). In addition, each medium was evaluated under a gas phase of 5% CO2 and 95% O2, 5% CO2 and 45% O2 and 50% N2, or 5% CO2 and 95% air. Culturing of explants with CMRL 1066 and medium 199 buffered with HEPES in the presence of 5% CO2 and air proved most efficient; ciliary movement and ciliated surface epithelium were maintained for periods up to 27 days. No significant difference in the rate of replication of Sendai virus was seen in the three different media with the two buffer systems in the three different gaseous phases. The addition of 0.2% bovine serum albumin to the media yielded greater quantities of virus, up to 200-fold increase in titer without producing changes in ciliary function. A distinctive pattern of morphological changes was observed in explants of trachea epithelia inoculated with Sendai virus. These results suggest the practical application in the use of whole hamster trachea explants as a diagnostic aid in the isolation of Sendai virus from laboratory rodents.
Presumptive speciation of Streptococcus bovis and other group D streptococci from human sources by using arginine and pyruvate tests
Authors: Gross K C , Houghton M P , Senterfit L B
Published: January 2020

A simplified method for speciation of group D streptococci is described. A total of 4,156 streptococcal isolates from human clinical material was tested for ability to hydrolyze esculin in the presence of 40% bile, ferment pyruvate, hydrolyze arginine, and grow in media containing 40% bile or 6.5% NaCl. Streptococci which hydrolyzed esculin in 40% bile, but which did not hydrolyze arginine, were also tested for their ability to ferment raffinose or sorbose. Sixty percent (2,503) of the isolates hydrolyzed esculin in the presence of 40% bile and were thus presumptively identified as group D. By application of the other criteria, 84% of these were speciated as Streptococcus faecalis, 7% were speciated as S. faecium, 6% were speciated as S. bovis, 2% were speciated as S. avium, and 1% were not identified. This scheme was shown to be both reliable and practical for use in the diagnostic laboratory. S. avium and S. bovis isolates were characterized, and 18 S. bovis isolates from patients with bacterial endocarditis were compared physiologically with 151 isolates of this species from other sources.
Comparison of four methods for determining nitrate utilization by cryptococci
Authors: Rhodes J C , Roberts G D
Published: January 2020

This study evaluated the following methods for determining nitrate utilization: Wickerham broth, a special nitrate broth, Delft plate, and nitrate strip. With 236 isolates of cryptococci as test organisms, the special nitrate broth method gave 99% correct results and the Wickerham broth method gave 98%. The nitrate strip and Delft plate methods gave correct results in 94 and 86% of tests, respectively. The special nitrate broth method is judged superior because it provides accurate results within 48 h, compared to 14 days with the Wickerham broth method.
Effect of sodium polyanethol sulfonate in blood cultures
Authors: Eng J
Published: January 2020

Fifteen-hundred hospital blood cultures were made in duplicate, with and without 0.05% sodium polyanethol sulfonate in the broth medium. A significantly higher rate and speed of recovery of both gram-positive cocci and gram-negative bacilli was accomplished in sodium polyanethol sulfonate broth. The effect was independent of the content of 0.1% agar in the growth medium. In the cases of Neisseria meningitidis septicemia examined, however, a detrimental result on recoveries was observed. The addition of sodium polyanethol sulfonate also resulted in an increased frequency of recoveries of contaminating organisms.
Bacteriology of normal and infected conjunctiva
Authors: Perkins R E , Kundsin R B , Pratt M V , Abrahamsen I , Leibowitz H M
Published: January 2020

The conjunctivas of 273 inflamed eyes were cultured by both aerobic and anaerobic techniques. Isolations were obtained from 267 (97.8%) of the eyes. Aerobic organisms were isolated from 237 (86.8%) of the conjunctivas. Staphylococcus aureus from 63 (23.1%) of the diseased eyes was the aerobic pathogen most often isolated. Anaerobic bacteria were isolated from 172 (63.0%) of the conjunctivas. Propionibacterium acnes was isolated from 126 (46.2%) of the conjunctivas, and Peptostreptococcus species were isolated from 80 (29.3%) of the conjunctivas. Comparison with the bacteriology of 96 normal eyes showed that anaerobes play a much greater role as etiological agents of conjunctivitis than formerly believed. When anaerobic bacteria were isolated, they appeared on the average in 7 days, indicating that they may be missed by ordinary bacteriological culturing.
Effect of aerobic and anaerobic atmospheres on isolation of organisms from blood cultures
Authors: Blazevic D J , Stemper J E , Matsen J M
Published: January 2020

Blood was cultured in two vacuum bottles containing Columbia broth. Filtered air was admitted to one bottle (aerobic); the unvented bottle was considered anaerobic. Cultures were incubated at 35 C until growth occurred or for at least 7 days. Of 744 organisms isolated, 50% were isolated from both bottles, 30% from the aerobic bottle only, and 20% from the anaerobic bottle only. These results indicate the need for use of both an aerobic and anaerobic bottle for blood cultures.
Stability of pathogenic colony types of Neisseria gonorrhoeae in liquid culture by using the parameters of colonial morphology and deoxyribonucleic acid transformation
Authors: La Scolea L J , Dul M J , Young F E
Published: January 2020

This investigation describes the surveillance of the colonial stability of the pathogenic type 1 from the gonococcal strain F62 to the nonvirulent types 3 and 4 in different liquid media. The maintenance of the colony types was monitored by the parameters of colonial morphology and deoxyribonucleic acid-mediated transformation. During growth in a complex medium, Mueller-Hinton broth, only 46.7% of the gonococcal population remained as type 1 after 12 h. The greatest change in the type 1 colony-forming units correlated with the decline in viable count. The conversion process could not be prevented by the continual maintenance of the gonococcus in logarithmic growth. The frequency of transformation from PRO(minus) (proline) to PRO(plus) was proportional to this decrease in type 1 colony-forming units. In contrast to Mueller-Hinton medium, the chemically defined minimal medium Gonococcal Genetic Medium (GGM) was capable of maintaining approximately 90% of the gonococcal population in the type 1 colonial form after 16 h of growth, despite a decrease in the viable count. Although the percentage of type 1 appeared to remain constant in GGM, the apparent transformation frequency increased approximately 24-fold from 0 to 12 h of growth. GGM appears to stimulate or maintain competence, as evidenced by an eightfold increase in transformation when cells are exposed to deoxyribonucleic acid in GGM as compared to Mueller-Hinton.
Standardization and evaluation of the CAMP reaction for the prompt, presumptive identification of Streptococcus agalactiae (Lancefield group B) in clinical material
Authors: Darling C L
Published: January 2020

Primary cultures of clinical material were screened for the presence of colonies suspected of being Streptococcus agalactiae (Lancefield group B). Sixty-three such cultures and 108 other isolates of beta-hemolytic streptococci (groups A, C, and G), encountered during the first 3 months of the investigation, were studied by Lancefield grouping, sodium hippurate hydrolysis, and a standardized CAMP test. All streptococci were inoculated perpendicularly to streaks of a beta-toxin-producing staphylococcus on sheep blood agar plates and incubated aerobically in a candle jar and anaerobically at 37 C. Plates were examined after 5 to 6 and 18 h of incubation. The production of a distinct "arrowhead" of hemolysis was indicative of a positive CAMP reaction. All group B streptococci produced a positive CAMP reaction in the candle jar or anaerobically, usually within 5 to 6 h, and aerobically after 18 h of incubation. All group A streptococci produced a positive reaction only under anaerobic conditions. Groups C and G streptococci were negative under all atmospheres. The CAMP reaction is a prompt and reliable procedure for the presumptive identification of group B streptococci when a candle jar atmosphere is used during incubation.
Reduced virulence of Pseudomonas aeruginosa grown in the presence of benzalkonium chloride
Authors: Adair F W , Liauw H L , Geftic S G , Gelzer J
Published: January 2020

Resistant cells of Pseudomonas aeruginosa ATCC 9027 which were grown in the presence of 1 mg of benzalkonium chloride (BC) per ml caused only a mild conjunctivitis when they were dropped onto the scratched corneas of rabbits. In contrast, cells of the BC-sensitive parent strain induced a severe keratoconjunctivitis. In addition, the BC-grown cells also had a reduced capacity to produce kidney infections in mice as compared to the parent strain. BC-grown cells acted as weak complex antigens which conferred slight protection against lethal doses of BC-grown cells. No cross-protection to cells of the parent strain occurred. The data indicate that growth in the presence of BC results in cells with reduced virulence.
Evaluation of turkey erythrocyte hemagglutination assay for the detection of hepatitis B antigen
Authors: Ramirez R I , Tiku M L , Ogra P L
Published: January 2020

A recently described hemagglutination test for hepatitis B antigen (HBsAg) using turkey erythrocytes coated with horse antibody to HBsAg purified by affinity column chromatography was evaluated on a comparative basis with 100 HBsAg-positive and -negative serum samples. The turkey erythrocyte hemagglutination test (TEHA) was found to be less sensitive than radioimmunoassay (RIA) but gave far better results than counterimmunoelectrophoresis. Quantitative titration of HBsAg in serial dilutions of the samples appeared to be more reliably performed by TEHA than by RIA. TEHA is a simple and sensitive technique for the detection of HBsAg and may offer several practical advantages over RIA.
Rapid identification of group B streptococci by counterimmunoelectrophoresis
Authors: Hill H R , Riter M E , Menge S K , Johnson D R , Matsen J M
Published: January 2020

Beta-hemolytic streptococcal isolates have been examined by counterimmunoelectrophoresis (CIE) with group B antiserum to determine whether this techinque is of value in the rapid identification of group B strains. Ninety stock cultures and 100 clinical isolates of beta-hemolytic streptococci including representatives of groups A, D, C, G, and B were inoculated into Todd-Hewitt broth; after incubation at 37 C for 1, 2, 3, and 4 h, aliquots of the whole broth cultures were removed and tested by CIE. Antigen was not regularly detected in the 1-, 2-, and 3-h samples, but after 4 h all 126 group B streptococcal strains identified by the capillary precipitin reaction gave CIE precipitin bands with group B antiserum. None of the 58 non-group B strains gave precipitin reactions with this antiserum. Cerebrospinal fluid from an infant with group B streptococcal meningitis and peritoneal fluid from a patient with group B streptococcal peritonitis had free group B antigen detected by the CIE technique. CIE of broth cultures and direct body fluids appears to be a rapid and sensitive method for the identification of group B streptococcal strains.
Use of electron microscopy for detection of viral and other microbial contaminants in bovine sera
Authors: Fong C K , Gross P A , Hsiung G D , Swack N S
Published: January 2020

A total of 25 lots of bovine serum samples were pelleted in Beem capsules for thin sectioning and were examined by electron microscopy. These included 17 lots of fetal bovine serum pools and five lots of calf serum pools obtained from commercial sources, and three lots of adult bovine serum from local dairy farms. Virus-like particles, 50 to 300 nm in diameter, were detected in 17 of 25 (68%) of the sera. Five of 25 serum samples showed the presence of mycoplasma-like agents. Incubation of bovine serum at 35 C for 1 or 2 weeks appeared to destroy some of these agents, but in certain instances it enhanced bacteria and bacteriophage contaminants. The advantages of electron microscopy using the thin-sectioning technique for detection of microbial contamination in bovine sera are illustrated.
Serotyping and biotyping of 160 Escherichia coli strains: comparative study
Authors: Van Der Waaij D , Speltie T M , Guinee P A , Agterberg C
Published: January 2020

One hundred and sixty Escherichia coli strains were serotyped and biotyped. Serotyping revealed 68 different types, with 25 strains not typable. Biotyping was possible in all strains but revealed 55 different types. One biotype could be subdivided into 35 different serotypes, indicating that for this biotype the series of biochemical and fermentation reactions could be extended for further differentiation.
Identification of streptococci: serogrouping by immunofluorescence
Authors: Watson B K , Kunz L J , Moellering R C
Published: January 2020

This paper deals with the fluorescent antibody (FA) method for identifying six commonly occuring and two rare groups of streptococci by using commercially prepared (Difco) conjugates. We have shown that group-specific FA produced frequent cross-reactions with heterologous groups of organisms. These reactions varied with different strains of the same serogroup. Nonetheless, there was distinct overall patterns in the intensity and appearance of the homologous and heterologous reactions. When monitored by the precipitin test with Rantz and Randall extracts, these patterns led to the correct identification of 90 to 100% of specimens of serogroup A, B, C, and G streptococci. Many members of groups D and F also showed distinctive reaction patterns. However, there was a significant number of strains of both groups D and F that either failed to strain or stained poorly with the homologous conjugate. As a result, the identification of these serogroups by FA was less reliable.
Bacterial aerosolization from an ultrasonic cleaner
Authors: Turner A G , Wilkins J R , Craddock J G
Published: January 2020

An ultrasonic device used for cleaning surgical instruments was found to produce a significant microbial aerosol. No correlation was found between the concentration of aerosol generated and the bacterial contamination in the cleaning solution. Table top contamination around the cleaner was due essentially to splash and dripping, and not from the settling of the aerosol. Recommendations are made for cleaning and disinfection protocols.
Antibody response of patients with malignancies to bacteremia with gram-negative bacteria
Authors: Surgalla M J , Neter E , Fitzpatrick J E
Published: January 2020

Antibody response, determined by means of the indirect bacterial hemagglutination tests, was studied in 58 consecutive patients with various malignancies whose blood culture yielded growth of Enterobacteriaceae or Pseudomonas and from whom serum specimens were obtained. Of these patients 59% had a significant antibody response. The invading microorganisms were Escherichia coli in 33 and Klebsiella in 19 subjects, an antibody response being documented with essentially equal frequency (60 and 57% of the subjects, respectively). Two patients had positive blood cultures for both E. coli and Klebsiella, one of whom had a significant response to one isolate only. A specific antibody resonse was documented in 67% of the subjects from whom blood for antibody titration was obtained at least 5 days after the blood culture, but from only 21% of patients whose serum was procured during the first 5 days after the blood culture. Similarly, such an antibody response was identified in 73% of subjects with two consecutive serum specimens, but in only 28% of the patients with a single serum specimen for antibody titration. Documentation of the immune response may be of diagnostic aid in differentiating between infection and contamination even in patients with underlying malignancy and under potentially immunosuppressive therapy.
Laboratory experience with a radiometric method for detecting bacteremia
Authors: Thiemke W A , Wicher K
Published: January 2020

Two bacteriologic systems for detecting bacteria in blood were compared; the automated radiometric BACTEC and the conventional method used in our laboratory for many years. BACTEC consisted of two bottles with 30 ml and the conventional method with 50 ml of media for aerobes and anaerobes. The BACTEC bottles were inoculated with 2 to 3 ml and the conventional with 4 to 5 ml of blood at the patient's bedside. Out of the 3,045 blood specimens cultured (804 patients), 262 (117 patients) were positive by one or both methods. The conventional system detected 5more cultures. The explanation of the differences is discussed. Positive blood cultures were detected by the BACTEC procedure as early as 6 h after the blood collection. In the first 24 h, on the average, 77% of aerobic organisms were detected by the BACTEC as compared to 48% by the conventional system. All anaerobic BACTEC cultures were positive within 4 days, whereas the conventional system detected at that time 74%. At day 4, 67% of fungi were detected by the BACTEC and only 27% by the conventional system. Of the 3,045 blood cultures examined by the BACTEC, 208 were recorded as false positive with growth index readings ranging from 30 to 59.
Detection of fungi in blood cultures
Authors: Roberts G D , Washington J A
Published: January 2020

In a retrospective study covering the period January 1972 to June 1974, recovery rates of bacteria and of fungi were generally equivalent with tryptic soy broth, Thiol, thioglycolate, and Columbia broth media (all under vacuum with carbon dioxide and sodium polyanetholesulfonate). An additional biphasic medium consisting of brain heart infusion broth and a brain heart infusion agar slant, which was inoculated only where fungal sepsis was suspected clinically, yielded significantly higher recovery rates of fungi. There were 29 instances of cultures with fungi in both the biphasic and broth media, 80 instances of cultures with fungi only in the biphasic medium, and no instances of fungi only in the broth media. The isolates were as follows: Candida albicans, 74; C. parapsilosis, 20; C. tropicalis, 16; Torulopsis glabrata, 18; Torulopsis sp., 1; Cryptococcus neoformans, 12; C. laurentii, 2; and Histoplasma capsulatum, 16. Despite routine subcultures of the broth media to chocolate blood agar within 24 h of inoculation and after 5 days of incubation, detection of fungemia was significantly improved by the use of a biphasic medium.
A simple test system for the separation of staphylococci from micrococci
Authors: Schleifer K H , Kloos W E
Published: January 2020

A simple test system for the separation of staphylococci from micrococci is described, which is based on the ability of staphylococci to produce acid aerobically from glycerol in the presence of 0.4 mug of erythromycin per ml and on their sensitivity to lysostaphin.
Fluorescent antibody studies in chlamydial infections
Authors: Richmond S J , Caul E O
Published: January 2020

Irradiated McCoy cells infected with genital strains of Chlamydia trachomatis were grown in wells on slides coated with polytetrafluoroethylene. The inclusions produced in this system formed the antigen in an indirect immunofluorescence test, which detected group-specific chlamydial antibodies in sera from patients attending veneral disease clinics. Chlamydial antibodies were found more frequently and in higher titer in sera from women attending veneral disease clinics then in sera from a less promiscuous population attending a Family Planning Association clinic. Paired sera from 13 patients with nongonococcal urethritis from whom chylamydiae had been isolated were tested against the homologous isolates; seroconversion was demonstrated in only one instance, and antibody was present in the first serum specimens of all the other patients. Chlamydia-specific immunoglobulin M was found in four of eight patients with psittacosis and in a proportion of sera from patients attending veneral disease and Family Planning Association clinics. The antigen for this immunofluorescence test can easily be prepared in laboratories with cell culture facilities for the isolation of C. trachomatis, and the test should be useful for laboratories which cannot undertake the micro-immunofluorescence test.
Detection of adenovirus in patient specimens by indirect immune electron microscopy
Authors: Valters W A , Boehm L G , Edwards E A , Rosenbaum M J
Published: January 2020

Immune electron microscopic procedures for the detection of adenovirus type 7 directly in throat swab specimens from patients are described. Nineteen of 25 throat swab samples, known to be positive for adenovirus type 7 by isolation of virus from tissue culture, were shown to contain aggregates of adenovirions coated with antibody. Sensitivity tests of the immune electron microscopic method showed that as few as 16 to 32 tissue culture infective doses of virus could be detected by the direct immune electron microscopic technique. It was also demonstrated that aggregation of virus-antibody complexes could be further enhanced by use of anti-immunoglobulin G sera (indirect immune electron microscopic procedures). These results demonstrate that examination of patient specimen by immune electron microscopic procedures is a feasible and rapid method for adenovirus detection and suggest that it could be applied as a routine laboratory procedure for the diagnosis of other virus infections.
Naturally occurring histoplasmosis in the chinchilla (Chinchilla laniger)
Authors: Owens D R , Menges R W , Sprouse R F , Stewart W , Hooper B E
Published: January 2020

Histoplasmosis was diagnosed histopathologically in a female chinchilla. This animal had originated from a commercial chinchilla ranch in central Missouri. Seventeen of 130 animals in the colony had died within a month's period with a respiratory illness. This animal had a history of fur chewing, but this was not true of all the other animals that had died. Histoplasma capsulatum was cultured from timothy hay used for food.
Growth potential of cottonseed culture media for various clinically significant aerobic bacteria
Authors: Slifkin M , Pouchet G
Published: January 2020

Enzymatic hydrolysates of various cottonseed flours were prepared with the proteolytic enzymes bromelain, HT-200, Pronase, and trypsin. The growth of various aerobic bacteria of clinical significance in these hydrolysates was compared to that obtained with a standard casein-soybean peptone culture medium, Trypticase soy. The generation times of the majority of bacteria grown in the bromelain cottonseed flour hydrolysate were shorter than that obtained with the standard control broth. A bromelain cottonseed flour hydrolysate agar preparation supported the growth of the bacteria comparably to that of the casein-soybean agar substrate. All the bacterial colonies were larger on the bromelain cottonseed flour hydrolysate blood agar medium than those grown on the control agar. The peptones derived from the enzymatic hydrolysis of cottonseed flour are sufficient to promote the rapid and luxuriant growth of a wide spectrum of aerobic bacteria without the addition of peptone from other sources. It is suggested that cottonseed flour peptones be utilized as a nutrient source in general-purpose media for the clinical microbiology laboratory.
Prosthetic valve endocarditis due to Mycobacterium chelonei
Authors: Altmann G , Horowitz A , Kaplinsky N , Frankl O
Published: January 2020

Postoperative prosthetic valve endocarditis due to Mycobacterium chelonei occurred in a man after replacement of the aortic valve. The organism was isolated from blood cultures and from vegetations taken postmortem from the edge of the inserted valve. This is believed to be the first documented report of a mycobacterial endocarditis.
Detection of Candida antigen in sera of patients with candidiasis by an enzyme-linked immunosorbent assay-inhibition technique
Authors: Segal E , Berg R A , Pizzo P A , Bennett J E
Published: January 2020

A total of 37 serum samples from 27 cancer patients were tested by an enzyme-linked immunosorbent assay-inhibition technique for the detection of Candida antigen. In 20 randomly chosen sera from patients without clinical evidence of candidiasis and in 10 sera from patients proven by autopsy not to have candidiasis, the inhibition ranged up to 17%; in contrast, inhibition ranged from 22 to 56% in all seven patients proven by autopsy to have systemic candidiasis, indicating the presence of Candida antigen in the sera of these patients. This technique appears promising in diagnosing disseminated candidiasis in cancer patients.
Comparison of different tissue cultures for isolation and quantitation of influenza and parainfluenza viruses
Authors: Frank A L , Couch R B , Griffis C A , Baxter B D
Published: January 2020

Rhesus and cynomolgus monkey kidney tissue cultures and two continuous lines, Madin-Darby canine kidney (MDCK) and LLC-MK2, were compared in titrations and isolations of influenza and parainfluenza viruses. Tube cultures were inoculated with laboratory virus strains or stored patient specimens and observed for hemadsorption. Trypsin was added to the medium of the continuous lines to increase sensitivity. All four tissue cultures gave similar titers of influenza A/USSR (H1N1), A/Texas (H3N2), and B/HK, but lower titers of parainfluenza 1, 2, and 3 were observed with MDCK. Cynomolgus kidney was the best single tissue culture for reisolation of the six viruses, but foamy-virus contamination of many lots was a serious problem. Reisolation of influenza viruses was as successful with MDCK as with primary monkey kidney. LLC-MK2 was similar to rhesus kidney but less successful than cynomolgus kidney. For reisolation of parainfluenza viruses, LLC-MK2 was superior to rhesus monkey kidney and similar to cynomolgus kidney. MDCK was less useful for parainfluenza viruses. Thus, LLC-MK2 would be an acceptable single tissue alternative to primary monkey kidney. The combination of MDCK and LLC-MK2 would provide optimal sensitivity for isolation of all six viruses.