bluuebunny/crossref_metadata_2025 huggingface dataset:
Action Spectrum for Carotenogenesis in
Myxococcus xanthus
Authors: Burchard Robert P. , Hendricks Sterling B.
Published: January 2020

An action spectrum was measured for photoinduction of colored carotenoids in dark-grown, early stationary-phase cells of
Myxococcus xanthus
. Maximum activity was observed at 405 to 410 nm with subsidiary maxima at 512, 533, 548, 585, and 635 nm. These maxima correspond closely in position and magnitude with absorption maxima of protoporphyrin IX, which had previously been isolated from
M. xanthus
cells and had been shown to increase during the stationary phase of the culture. Late stationary-phase, dark-grown cells undergo photolysis which had been shown to have an action spectrum resembling the absorption spectrum of protoporphyrin IX. The similarity of the action spectra of photolysis and photoinduced carotenogenesis in
M. xanthus
and of other photoinduced biological phenomena is discussed.
Inhibition of 3-Deoxy-
d
-Arabinoheptulosonic Acid-7-Phosphate Synthetase (trp) in
Escherichia coli
Authors: Pittard J. , Camakaris J. , Wallace B. J.
Published: January 2020

The growth of a strain of
Escherichia coli
K-12 which possesses only the single isoenzyme 3-deoxy-
d
-arabinoheptulosonic acid-7-phosphate (DAHP) synthetase (trp), and which makes this enzyme constitutively, is inhibited by tryptophan. The accumulation of DAHP by a derivative of this strain unable to convert DAHP to dehydroquinate is also inhibited by tryptophan. The enzymic activity of DAHP synthetase (trp) in the presence of CO
2+
is sensitive to inhibition by tryptophan. Mutant strains of
E. coli
have been isolated in which DAHP synthetase (trp) is feedback-resistant.
Resistance Factor-mediated Streptomycin Resistance
Authors: Harwood J. H. , Smith David H.
Published: January 2020

Resistance (R) factor-mediated streptomycin (Sm) resistance differs from classical, high-level, chromosome-borne Sm resistance in its dominance over sensitivity and in the level of its effectiveness (inEscherichia coli∼25 μg/ml versus >2,000 μg/ml). In addition, an R factor-containing strain, unlike high-level Sm-resistant bacteria, showed an inoculum effect with respect to its level of Sm resistance. Crude extracts of this strain destroyed the inhibitory activity of Sm and bluensomycin (Blue) on in vitro protein synthesis. The ribosomes from this strain proved to be sensitive to Sm in vitro. The requirements for in vitro inactivation of Sm (and Blue) were determined to be: extract, adenosine triphosphate or deoxyadenosinetriphosphate, and Mg++. Chromatographic techniques with radioisotopes revealed the formation of an inactivated form of Sm containing adenosine (or deoxyadenosine), phosphate, and Sm in equimolar amounts. The adenylate moiety is coupled to the streptobiosamine residue, rather than to the streptidine ring, of the Sm molecule. The adenylating enzyme, which is not induced by Sm, is located in the periplasmic space of the R factor-containing strain.
Detection of Polysaccharide, Teichoic Acid, and Protein Antigens in Bacterial Colonies on an Agar Surface
Authors: Deddish Peter A. , Slade Hutton D.
Published: January 2020

An improved method of using fluorescein-labeled antibody for the detection of polysaccharide, protein, and teichoic acid antigens synthesized by streptococcal colonies on an agar surface is described. The bacteria were grown on the surface of an agar medium contained in the shallow well of an immunodiffusion slide. An agar overlay containing the fluorescein antiserum was dispensed over the colonies, excess antiserum was washed out of the overlay agar, and the fluorescent colonies were observed under an ultraviolet microscope. The shallow well in the immunodiffusion slide prevented the agar from floating loose during washing, and the agar overlay prevented the fragmentation and loss of colonies. The thin layer of agar facilitated microscopic examination and the counting of fluorescent and nonfluorescent colonies. Colonies producing an antigen against which the antiserum was directed could readily be distinguished from colonies not producing the antigen. The specificity of the method was shown by using mixtures of streptococci representing six serological groups and five types. Those not known to possess cross-reacting antigens were specific in their reaction to the fluorescein antibody. Cross-reactions between the group antigens of A, C, and G, as reported previously by fluorescent staining of streptococcal suspensions, were also seen. Group A colonies reacted weakly with fluorescent E antibody and vice versa. The extraction of this antigen with cold trichloroacetic acid indicates it was related to the teichoic acids. Colonies possessing polysaccharide, protein, and teichoic acid antigens gave equally strong fluorescent reactions. This procedure permits detection of the synthesis of antigen which could not be observed by the use of a selective medium; it also eliminates the necessity for subculture of each colony and testing by appropriate serological means. Such a technique has value for studies in classification and biochemical genetics, and should be applicable to other genera of bacteria.
Serine Biosynthesis and Regulation in
Haemophilus influenzae
Authors: Pizer Lewis I. , Ponce-De-Leon Manuel , Michalka Jack
Published: January 2020

Nutritional mutants of
Haemophilus influenzae
requiring
l
-serine for growth were shown to be deficient in their capacity to synthesize serine-phosphate from 3-phosphoglycerate. On the basis of the correlation between this block and the requirement for an exogenous supply of the amino acid, it was concluded that the “phosphorylated” pathway is the only pathway used by
H. influenzae
for serine biosynthesis. Serine inhibits serine-phosphate production, thereby regulating its own synthesis in a manner analagous to the
Enterobacteriaceae
. A mutant strain that required either serine or tryptophan for growth was normal in serine-phosphate synthesis and regulation. It was concluded that this strain probably has a tryptophan synthetase with an increased Michaelis constant for serine.
Growth of Large Plasmodia of the Myxomycete
Physarum polycephalum
Authors: Mohberg Joyce , Rusch Harold P.
Published: January 2020

A method has been developed for growing
Physarum polycephalum
plasmodia that are 8 to 10 times larger than those obtained in the petri dish cultures used by Nygaard, Guttes, and Rusch. In the large-scale procedure, plasmodia were grown in metal trays on a membrane supported by filter paper on stainless-steel screen. Plasmodia were started from a ring of inoculum to allow inward and outward migration and were incubated on a rocker so that nutrient medium would flow back and forth, wetting the undersurface of the plasmodium. Rocker and petri dish cultures had similar growth characteristics: (i) the interphase time between mitoses I and II and between II and III was about 8 hr; (ii) ribonucleic acid and protein increased essentially logarithmically throughout the cell cycle; and (iii) deoxyribonucleic acid increased only during early interphase and it doubled in approximately 3 hr after each mitosis. Rocker cultures were not as nearly synchronous as petri dish cultures and had a range in metaphase time (at mitosis III) within individual plasmodia of 15 to 45 min, as compared with 5 to 10 min in petri dish cultures.
Electron Microscopic Examination of
Corynebacterium ovis
Authors: Hard G. C.
Published: January 2020

Corynebacterium ovis
(
C. pseudotuberculosis
) was examined by electron microscopy after being subjected to various methods of fixation. The organism exhibited a fine structure similar to other corynebacterial species in the appearance of its cell wall, plasma membrane, nuclear apparatus, cytoplasmic matrix, wealth and complexity of intracytoplasmic membrane systems, and polyphosphate granules. An outstanding structural feature was the existence of an electron-dense, floccular layer external to the cell wall which both ligroin and acetone-methanol extractions demonstrated to be the previously postulated surface lipid of this organism. The only variations in structure evident between virulent and attenuated strains was a quantitative difference in the thickness and appearance of the surface lipid. The observation of this layer provided a basis for explaining the surface properties of
C. ovis
, with particular respect to its clumping capacity in suspension, the waxiness of its growth on solid media, and its ability to grow as a pellicle on suitable liquid media. The variation in the visible amount of surface lipid between the virulent and avirulent strains adequately explained the divergence of these three surface properties between the strains.
Growth of Trachoma Agent in Primary Cultures of Rabbit Corneal Endothelial Cells
Authors: Oh J. O. , Tarizzo M. L. , Yoneda C.
Published: January 2020

Primary cultures of rabbit corneal endothelial cells supported growth of trachoma agent, as evidenced by the production of inclusions and an increase of infectivity titers.
Localization of Certain Indigenous Microorganisms on the Ileal Villi of Rats
Authors: Savage Dwayne C.
Published: January 2020

Long gram-negative chains of either rod- or coccal-shaped bacteria are localized on the villous epithelium in the rat ileum.
Deoxyribonucleic Acid Sequence Losses in a Stable Streptococcal L Form
Authors: Hoyer Bill H. , King James R.
Published: January 2020

A portion of the deoxyribonucleic acid sequences present in
Streptococcus faecalis
were absent in its stable L form. The remaining sequences were common to both forms.
Formation of Recombinants Between Nontransmissible Drug-Resistance Determinants and Transfer Factors
Authors: Mitsuhashi Susumu , Kameda Mitsuo , Harada Kenji , Suzuki Mitsue
Published: January 2020

Noninfectious drug-resistance determinants acquired conjugal transmissibility by the formation of recombinants with transfer factors, suggesting the origin of R factors.
Plaquing of
Toxoplasma gondii
in Secondary Cultures of Chick Embryo Fibroblasts
Authors: Foley Virginia L. , Remington Jack S.
Published: January 2020

A tissue culture system that employed chick embryo fibroblasts was described for plaquing of the obligate intracellular parasite
Toxoplasma gondii
. High plaquing efficiency and reproducibility were accomplished by the use of secondary rather than primary cultures and the use of toxoplasma obtained from disrupted peritoneal cells of mice infected 48 hr earlier. The monolayers were cultured in a special medium which maintained the fibroblasts until the maximal number of plaques was produced. Optimal plaque formation was obtained in 5 days, and the plaques were easily counted macroscopically.
Isolation of Amino Acid Transport-negative Mutants of
Pseudomonas aeruginosa
and Cells with Repressed Transport Activity
Authors: Kay W. W. , Gronlund Audrey F.
Published: January 2020

Methods are described for the isolation of amino acid transport-negative mutants of
Pseudomonas aeruginosa
and for the preparation of cells with repressed, specific amino acid permeases.
P. aeruginosa
was resistant to high concentrations of the majority of the 53 amino acid analogues examined and was unaffected by low concentrations of any of them. Cells which had been grown in the presence of sublethal concentrations of the few analogues which were inhibitory were subsequently more resistant to the analogues. These cells were also defective in the transport of the corresponding amino acid, as the analogue caused repression of the synthesis of the specific amino acid permease. The cells with repressed transport activity rapidly regained their normal level of constitutive permease when grown in the absence of the analogue. Higher levels of the permeases were induced when these cells were grown in the presence of the appropriate amino acid. The possible mechanisms for the mode of regulation of amino acid permeases are discussed.
Effect of Growth Rate on Histidine Catabolism and Histidase Synthesis in
Aerobacter aerogenes
Authors: Jensen Donald E. , Neidhardt Frederick C.
Published: January 2020

A study was made of how the catabolism of a carbon and energy source is affected by the biosynthetic demands of growing bacterial cells. Cultures of
Aerobacter aerogenes
in
l
-histidine medium were grown in a chemostat at rates determined by the supply of either sulfate or a required amino acid,
l
-arginine. It was discovered that the rate at which these cells grow under a biosynthetic restriction determines both the rate and the pattern of histidine degradation. (i) Histidine catabolism is partially coupled to the growth rate. This coupling is achieved by catabolite repression of histidase (histidine ammonia lyase; EC 4.3.1.3.), and also by a slightly decreased in vivo function of this enzyme at low growth rates. (ii) The looseness of the coupling results in a direct relationship between growth rate and growth yield, and possibly is correlated with an altered pattern of carbon flow from histidine. (iii) Sudden decreases in growth rate cause total repression of histidase synthesis for substantial periods of time. (iv) Sudden release of biosynthetic restriction leads rapidly to an increase in the functioning of the cells' complement of histidase, an increase in the rate of synthesis of this enzyme, and an increase in the growth yield from histidine.
Oxidation of
d
-Malic and β-Alkylmalic Acids by Wild-Type and Mutant Strains of
Salmonella typhimurium
and by
Aerobacter aerogenes
Authors: Stern Joseph R. , O'Brien R. W.
Published: January 2020

A mutant strain of
Salmonella typhimurium
(SL 1634
dml-51
) capable of growth on
d
-malate as sole carbon source was shown to produce
d
-malic enzyme. This enzyme was absent in the parent wild-type strain which was unable to grow on
d
-malate. Growth of the mutant on
d
-malate also resulted in a greatly increased level of β-isopropylmalic enzyme compared with its level in the wild-type strain grown on citrate or
l
-malate. The
d
-malic and β-isopropylmalic enzymes, both of which catalyze a nicotinamide adenine dinucleotide- and Mg
++
-dependent oxidative decarboxylation of their respective substrates, were shown to be distinct enzymes by selective inhibition with
erythro
-
dl
-β-hydroxyaspartate and by other methods. Cell extracts of the mutant strain also oxidized
dl
-β-methyl-,
dl
-β-ethyl-,
dl
-β-propyl- and
dl
-ββ-dimethylmalates, in order of decreasing activity.
dl
-β-Methyl-malate was shown to be oxidized by both the
d
-malic and the β-isopropylmalic enzymes, whereas the oxidation of the other β-alkylmalates appeared to be effected exclusively by the β-isopropylmalic enzyme. β-Isopropylmalic enzyme activity was induced by
d
-malate but not by
l
-malate, showing that it behaved as a
d
-malictype enzyme. Growth of
Aerobacter aerogenes
on
d
-malate, which caused induction of
d
malic enzyme, resulted in only a small increase in the activity of β-isopropylmalic enzyme.
Lipids of
Pseudomonas aeruginosa
Cells Grown on Hydrocarbons and on Trypticase Soy Broth
Authors: Edmonds Paul , Cooney J. J.
Published: January 2020

Lipids were extracted from cells of
Pseudomonas aeruginosa
grown on a pure hydrocarbon (tridecane), mixed hydrocarbons (JP-4 jet fuel), and on Trypticase Soy Broth. Total lipids produced from each substrate represented from 7.1 to 8.2% of cellular dry weight, of which 5.0 to 6.4% were obtained before cellular hydrolysis (free lipids) and 1.7 to 2.0% were extracted after cellular hydrolysis (bound lipids). Free lipids from cells grown on each medium were separated into four fractions by thin-layer chromatography. All fractions were present in cells from each type of medium, and the “neutral fraction” constituted the largest fraction. The fatty acid composition of free lipids was determined by gas-liquid chromatography. Cells grown on each medium contained saturated and unsaturated C
14
to C
20
fatty acids. Trace amounts of C
13
fatty acids were found in tridecane-grown cells. Saturated C
16
and C
18
were the major acids present in all cells. Quantitative differences were found in fatty acids produced on the three media, but specific correlations between substrate carbon sources and fatty acid content of cells were not evident. Tridecane-grown cells contained only traces of C
13
acid and small amounts of C
15
and C
17
acids, suggesting that the organism's fatty acids were derived from de novo synthesis rather than by direct incorporation of the hydrocarbon.
Tryptophanase in Diverse Bacterial Species
Authors: DeMoss R. D. , Moser K.
Published: January 2020

The distribution of tryptophanase was studied. The highest observed specific activity, μmoles per minute per milligram (dry weight) cells, is given in parentheses after each species. Tryptophanase was inducible and repressible in
Escherichia coli
(.914),
Paracolobactrum coliforme
(.210),
Proteus vulgaris
(.146),
Aeromonas liquefaciens
(.030),
Photobacterium harveyi
(.035),
Sphaerophorus varius
(.021),
Bacteroides
sp. (.048), and
Corynebacterium acnes
(.042). The enzyme was constitutive and nonrepressible in
Bacillus alvei
(.013), and was inducible but not repressible by glucose in
Micrococcus aerogenes
(.036). Indole-positive bacteria were found in fecal or intestinal samples from a variety of animals among the mammals, reptiles, insects, molluscs, fish, crustaceans, and amphibians.
Production and Catabolite Repression of the Constitutive Polygalacturonic Acid
trans
-Eliminase of
Aeromonas liquefaciens
Authors: Hsu Edward J. , Vaughn Reese H.
Published: January 2020

Production of polygalacturonic acid (PGA)
trans
-eliminase was greatly stimulated under conditions of restricted growth of
Aeromonas liquefaciens
. This was accomplished either by substrate restriction in a continuous-feeding culture or by restricting divalent cations in a batch culture, with the use of PGA as the sole source of carbon in a chemically defined medium containing inorganic nitrogen. Slow feeding of glucose, glycerol, or PGA to carbon-limited cultures allowed PGA
trans
-eliminase to be formed at a maximum differential rate 500 times greater than in batch cultures with excess substrate present. The differential rate of enzyme formation obtained by slow feeding of these three substrances or of a mixture of PGA plus glucose was observed to be the same. Therefore, PGA
trans
-eliminase produced by
A. liquefaciens
, contrary to the current view, appears to be constitutive. These observations also indicate that production of PGA
trans
-eliminase is subject to catabolite repression and that limiting the substrate reverses this repression. It was also found that, under conditions of unrestricted growth, any compound which the bacteria can use as a source of carbon and energy repressed constitutive PGA
trans
-eliminase production. The heritable reversal of catabolite repression of PGA
trans
-eliminase synthesis was demonstrated by isolation of mutant strain Gc-6 which can readily synthesize the constitutive catabolic enzyme PGA
trans
-eliminase while growing in the presence of excess substrate.
Effect of Lytic Enzymes of
Acanthamoeba castellanii
on Bacterial Cell Walls
Authors: Rosenthal Spencer , Reed Elizabeth J. , Weisman Robert A.
Published: January 2020

Extracts of
Acanthamoeba castellanii
(Neff) contain α- and β-glucosidase, β-galactosidase, β-
N
-acetylglucosaminidase, amylase, and peptidase. All of these activities are optimal between
p
H 3 and 4. These extracts also were found to clarify suspensions of cell walls from nine different gram-positive bacteria, including
Micrococcus lysodeikticus
. The
p
H optimum for the lytic activity was between 3 and 4. The extent of lysis of the various cell walls did not correlate with the release of free amino groups and of free
N
-acetylated sugars from the walls during digestion with these extracts. Suspensions of cell walls of
Escherichia coli
(a gram-negative bacterium),
Cordiceps militaris
(a fungus), and
Acanthamoeba
cysts, as well as of colloidal chitin, were not clarified by incubation with these extracts, although reducing sugars were released from each of these materials. Exhaustive digestion of
M. lysodeikticus
walls by lysozyme released no free
N
-acetylglucosamine. The products of exhaustive digestion of this cell wall with
Acanthamoeba
extracts were free
N
-acetylglucosamine, free
N
-acetylmuramic acid, glycine, alanine, glutamic acid, lysine, and
N
-acetylmuramic acid peptide fragments. These results suggest that the amoeba extracts contain endo- and exo-hexosaminidases, in addition to β-hexosaminidase and peptide hydrolases.
Fluorescent Europium Chelate Stain
Authors: Scaff W. L. , Dyer D. L. , Mori K.
Published: January 2020

The europium chelate of 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (thenoyl-trifluoroacetone; TTA) is firmly bound to microorganisms. It fluoresces brightly at 613 nm with activation at 340 nm. Cells may be stained with 10
−3
m
chelate in 50% ethyl alcohol, followed by washing with 50% ethyl alcohol. Equal or better stains are produced with 10
−3
m
aqueous europium salt, water wash, and 10
−2
m
aqueous TTA. A noncomplexing buffer should be used to maintain the
p
H at 6.5 to 6.8.
Analytical Studies on Regeneration of Protoplasts of
Geotrichum candidum
by Quantitative Thin-Layer-Agar Plating
Authors: Fukui Komei , Sagara Yasunobu , Yoshida Nagayuki , Matsuoka Toshiro
Published: January 2020

A preparation of pure protoplasts of
Geotrichum candidum
became osmotically stable and colonies developed when the protoplasts were embedded in stabilizing thin-layer-agar and incubated with stabilizing basal medium. When growing protoplasts were exposed to distilled water and then reincubated with basal medium, the process of regeneration of protoplasts could be quantitatively demonstrated by counting colonies. The process was divided into three phases, lag, logarithmic, and stationary. Furthermore, the state of regeneration of protoplasts at each phase could be seen in detail by microscopic studies of protoplasts under similar growth conditions. In the lag phase, which lasted for 2 hr after inoculation, protoplasts were completely destroyed when placed in distilled water. During the logarithmic phase, from 2 to 5 hr after inoculation, protoplasts rapidly became osmotically stable and about 18% of them were growing. In the stationary phase, most protoplasts developed germ tubes within 2 hr. These results suggested that there are two main phases, although individual cells passed through three different conditions, osmotically labile, osmotically stable, and growing. No apparent structure of cell wall material could be detected by electron microscopy on the surface of the membrane of these osmotically stable cells.
Abnormal 30
S
Ribosomal Subunits Determined by an
Ochre
Suppressor Mutation in
Escherichia coli
Authors: Reid Parlane , Gartner T. K. , Orias E.
Published: January 2020

The results demonstrate that an
ochre
suppressor mutant of
Escherichia coli
K-12 produces abnormal 30
S
ribosomes. The production of these abnormal 30
S
ribosomes is probably a secondary consequence of the suppressor mutation.
Correlation Between Plaque Size and Spore Size in
Dictyostelium discoideum
Authors: Cotter David A. , Hohl Hans R.
Published: January 2020

Haploid spores usually lead to the production of small plaques when plated under standard conditions; diploid spores usually lead to the formation of large plaques.
Technique for Screening 2
n
Combinations of Nutritional Requirements
Authors: Zubrzycki Leonard , Levinson Susan U. , Braverman Shirley
Published: January 2020

An auxanographic technique is described, which makes it possible to screen 2
n
combinations of nutrients on relatively few agar plates.
Isolation and Characterization of Arabinose Mycolate from Firmly Bound Lipids of Mycobacteria
Authors: Azuma Ichiro , Yamamura Yuichi , Misaki Akira
Published: January 2020

The glycolipid,
d
-arabinose-5-mycolate, was purified from bound lipids of mycobacteria. The significance of this glycolipid in the chemical structure of cell wall and wax D is discussed. The hypothetical chemical structure of mycolic acid-arabinogalactan portion of cell wall and wax D is proposed.
Regulation of Nitrogen Fixation in
Azotobacter vinelandii
OP: the Role of Nitrate Reductase
Authors: Sorger George J.
Published: January 2020

A number of chlorate-resistant mutants were selected, and one of these, clr68-5, was studied in detail. This mutant cannot utilize nitrate in vivo to overcome the effect of nonmetabolizable repressors of nitrogenase. The reason for this inability was that strain clr68-5 lacked nitrate reductase. Nitrate inhibited the activity of nitrogenase but did not act as a corepressor of nitrogenase in strain clr68-5 as it does in the wild type. Ammonia seemed to act as corepressor of nitrogenase in both strains.
Biochemical Studies of Bacterial Sporulation and Germination XII. A Sulfonic Acid as a Major Sulfur Compound of
Bacillus subtilis
Spores
Authors: Bonsen Pieter P. M. , Spudich James A. , Nelson David L. , Kornberg Arthur
Published: January 2020

A sulfonic acid found to be a major constituent of spores of
Bacillus subtilis
was provisionally identified as 3-
l
-sulfolactic acid. This compound was completely absent from vegetative cells during growth, but large amounts accumulated in sporulating cells just before the development of refractile spores. Essentially all of the accumulated sulfolactic acid was eventually incorporated into the nature spore, where it may represent more than 5% of the dry weight of the spore. Germination resulted in the rapid and complete release into the medium of unaltered sulfolactic acid. This compound was not found in spores of
Bacillus megaterium, B. cereus
, or
B. thuringiensis
.
Ferrous-activated Nicotinamide Adenine Dinucleotide-linked Dehydrogenase from a Mutant of
Escherichia coli
Capable of Growth on 1,2-Propanediol
Authors: Sridhara S. , Wu T. T. , Chused T. M. , Lin E. C. C.
Published: January 2020

A nicotinamide adenine dinucleotide-linked dehydrogenase has been partially purified from a mutant of
Escherichia coli
K-12 able to grow on
l
-1,2-propanediol as carbon and energy source. This enzyme catalyzes the dehydrogenation at carbon 1 of
l
-1,2-propanediol, glycerol, 1,3-propanediol, ethylene glycol, and ethyl alcohol. The purified protein requires added ferrous or managanous ions. The
V
max
and the apparent
K
m
for a given substrate vary with the particular metal used.
Extrachromosomal Control of Methicillin Resistance and Toxin Production in
Staphylococcus aureus
Authors: Dornbusch Kathrine , Hallander Hans O. , Löfquist Finn
Published: January 2020

All of 41 naturally occurring coagulase-positive methicillin-resistant strains of
Staphylococcus aureus
isolated in various laboratories were resistant to several antibiotics and were lipase-negative. Most strains produced hemolysins, and 38 strains produced enterotoxin B. Acriflavine treatment of four strains resulted in elimination of resistance to methicillin and mercury; in one strain, resistance to cadmium was also lost. Production of enterotoxin B and β-hemolysin was eliminated in all four strains and penicillinase production was eliminated in one strain. In transduction experiments, methicillin resistance and enterotoxin B production were transferred together at a frequency of 0.2 × 10
−8
to 1.1 × 10
−8
by use of ultraviolet-induced phage lysates from naturally lysogenic methicillin-resistant strains. Cotransductions of resistance to mercury and cadmium, as well as production of penicillinase and β-hemolysin, were obtained to some extent. The extrachromosomal character of these determinants and their possible genetic association are discussed.
Effect of Formaldehyde on the Immunogenicity of Staphylococcal Enterotoxin B for
Macaca mulatta
Authors: Silverman Sidney J. , Moore Gary T. , Roessler William G.
Published: January 2020

Monkeys were immunized with enterotoxin and enterotoxoid by intracutaneous injection or by feeding. Identical schedules were used to compare the effectiveness of the two antigens and the two routes. Enterotoxin administered intracutaneously was the most effective antigen, whereas oral administration of enterotoxoid was least effective. Intracutaneous injection of toxoid and oral feeding of toxin were intermediate and not too dissimilar in effectiveness. Antibody titers and protection persisted for at least 1 year at a relatively high level. Monkeys that had preimmunization hemagglutinins showed an anamnestic response after immunization. The development of protection and the appearance of antibodies subsequent to feeding toxin or toxoid suggest that ingestion of food contaminated by staphylococci or their metabolites may be one cause for the appearance of antitoxin in the serum of supposedly unexposed animals and man.
Erythromycin-inducible Resistance in
Staphylococcus aureus:
Survey of Antibiotic Classes Involved
Authors: Weisblum Bernard , Demohn Veronika
Published: January 2020

Certain erythromycin-resistant strains of
Staphylococcus aureus
remain sensitive to other macrolide antibiotics. If these strains are exposed to low levels of erythromycin, resistance to other antibiotics is induced. The antibiotics to which resistance is induced by erythromycin include: other macrolides as well as lincosaminide, streptogramin (group B) antibiotics but not chloramphenicol, amicetin, streptogramin (group A) antibiotics, tetracyclines, and aminoglycosides. Hence erythromycin induces resistance exclusively towards inhibitors of 50
S
ribosomal subunit function and, thus far, only with respect to three of six known classes of inhibitors which act on this subunit. In the four strains tested, erythromycin did not induce resistance to pactamycin or bottromycin, to fusidic acid (which inhibits a function involving both subunits), or to other antibiotics which do not inhibit ribosomal function. Thus, by inducing resistance erythromycin could antagonize the action of other antibiotics, and a consistent pattern of antagonism was observed to each antibiotic class in all of the strains in which this could be tested, as well as to other antibiotic members of the same chemical class in each bacterial strain.
Antigenic Heterology Between Flagellin and Flagella of
Bacillus subtilis
Authors: Ichiki Albert T. , Martinez Rafael J.
Published: January 2020

The antigenic properties of
Bacillus subtilis
flagella and periodate-treated flagellin were compared by using immobilization-inhibition and diethylaminoethyl cellulose binding assay. The results suggest that there are both unique and cross-reactive antibodies elicited by
B. subtilis
flagella and flagellin.
Immunochemistry of the Cell Walls of
Listeria monocytogenes
Authors: Ullmann William W. , Cameron J. A.
Published: January 2020

The antigenic specificity of
Listeria monocytogenes
types I, II, III, IVa, and IVb was studied by immunochemical techniques. Immunologically active carbohydrates of the various types were extracted from cell walls and were chemically analyzed. Types I and II contained predominantly glucosamine and rhamnose; type III, galactose, rhamnose, and glucosamine; and types IVa and IVb, glucose and galactose. Quantitative precipitin inhibition tests with purified monosaccharides indicated that the major antigenic determinant of types I and II is rhamnose. Precipitin reactions could not be detected with type III carbohydrate and homologous or heterologous antisera. The major determinants of types IVa and IVb were found to be galactose and glucose, respectively. As much as 87% inhibition of the quantitative precipitin test for types I and II was obtained with rhamnose, 72% for type IVa with galactose, and 72% for type IVb with glucose. The immunochemical basis for the antigenic specificity of
L. monocytogenes
types I, II, IVa, and IVb was further confirmed by using agar gel diffusion. Cross-reactions among the various type-specific carbohydrates and heterologous antisera were also studied. Type II carbohydrate was found to contain galactose and react with type IVa antisera. This reaction could be blocked by galactose. Type I carbohydrate did not contain galactose nor did it react with antiserum prepared from type IVa cells. Therefore, the somatic antigens of type I and type II
L. monocytogenes
, previously thought to be identical, appeared to differ. The dominant immuno-specific group in the cross-reaction between type IVb carbohydrate and type IVa antisera was found to be galactose. Type IVa absorbed antisera did not produce a significant cross-reaction with type IVb carbohydrate. The results obtained from this investigation indicate a lesser degree of antigenic relationship between type IVa and type IVb
L. monocytogenes
than was previously believed to exist.
Isolation and Amino Acid Composition of Ribosomal Proteins from
Bacillus stearothermophilus
Authors: Ansley Steven B. , Campbell L. Leon , Sypherd Paul S.
Published: January 2020

Twelve of the proteins from the 30
S
ribosome of
Bacillus stearothermophilus
were isolated by preparative disc electrophoresis. Amino acid analyses of these proteins showed them to be different from each other. The gross amino acid composition of 30
S
ribosomal protein from
B. stearothermophilus
and
Escherichia coli
are virtually identical. A number of the proteins of
B. stearothermophilus
had electrophoretic mobilities similar or identical to 30
S
ribosomal proteins of
E. coli
. However, there was little similarity between the two organisms in amino acid composition of individual proteins. There were no unusual chemical features of the
B. stearothermophilus
proteins which could explain the relative thermal stability of this organism's ribosomes.
Chromosome Transfer from F-
lac
+
Strains of
Escherichia coli
K-12 Mutant at
recA, recB
, or
recC
Authors: Wilkins Brian M.
Published: January 2020

The frequency of chromosome transfer from various recombination-deficient F-
lac
+
donor strains was estimated by standardizing the yield of conjugants receiving a male chromosomal marker against the level of episome transfer in the mating mixture. The efficiency of chromosome transfer from newly formed F-
lac
+
cells carrying
recB21
or
recC22
was more than 50% of the wild-type value, although it was about 10 and 20%, respectively, if the male cell lines had become established. In contrast,
recA13
donors transmitted the chromosome with less than 10
−4
of the normal frequency. If chromosome transfer from F-
lac
+
strains reflects the cutting and subsequent joining of homologous single strands of episomal and chromosomal deoxyribonucleic acid by recombination, these results imply that the completed unions are not made in
recA
cells, but can be effected with more than 50% of normal efficiency in newly formed partial diploids mutant at either
recB
or
recC
. Thus, the defective stage in
recA
mutants may precede strand joining, whereas the deficiency in
recB
or
recC
cells may involve a later step in recombinant formation.
Effect of Salts and Organic Solvents on the Activity of
Halobacterium cutirubrum
Catalase
Authors: Lanyi Janos K. , Stevenson Joann
Published: January 2020

Catalase in extracts of the extreme halophile
Halobacterium cutirubrum
exhibits up to threefold stimulation by 0.5 to 1.5
m
monovalent salts and by 0.1
m
divalent salts. Above these concentrations, inhibition of enzyme activity is observed. The inhibitory effect, and to some extent the stimulation, is salt-specific; the effectiveness of a salt in inhibiting enzyme activity depends on both cation and anion. Thus, the order of effectiveness is MgCl
2
> LiCl > NaCl > KCl > NH
4
Cl, and LiCl > LiNO
3
> Li
2
SO
4
. The magnitude of enzyme inhibition for the salts tested is positively correlated with their molar vapor pressure depression in aqueous solution. Stimulation of enzyme activity was observed when one salt was added at its optimal concentration in the presence of inhibiting concentrations of another salt, indicating that the effect on the enzyme is not due to changing water activity but probably to enzyme-salt interaction. Aqueous solutions of ethylene glycol, glycerol, and dimethyl sulfoxide containing no ions influence enzyme activity in the same manner as do salts.
Mixotrophic Growth of
Hydrogenomonas eutropha
Authors: Rittenberg Sydney C. , Goodman Nelson S.
Published: January 2020

Mixotrophic growth conditions were established by the addition of lactate to cultures of
Hydrogenomonas eutropha
growing autotrophically in a gaseous environment of H
2
, O
2
, and CO
2
(6:2:1). The specific growth rate of mixotrophic cultures was double that of the autotrophic cultures, and lactate disappearance paralleled growth. Growth yields in mixotrophic cultures were significantly greater than those in heterotrophic cultures for equal quantities of lactate consumed. The magnitude of the increase in yield was directly proportional to the absolute growth rate at the time of lactate addition to the starting autotrophic culture and to the time under mixotrophic conditions. The specific activities of hydrogenase and ribulose diphosphate carboxylase decreased during mixotrophic growth; the total activities increased somewhat. The results suggested that the complete autotrophic and heterotrophic physiologies functioned simultaneously under mixotrophic contions.
Inhibitory Effect of 2-Deoxy-
d
-Glucose on the Formation of the Cell Wall in Yeast Protoplasts
Authors: Farkaš V. , Svoboda A. , Bauer Š.
Published: January 2020

2-Deoxy-
d
-glucose (2DG) acted as a competitive inhibitor of the synthesis of cell wall components in
Saccharomyces cerevisiae
protoplasts. The synthesis of fibrillar glucan cell wall component was inhibited at a glucose to 2DG ratio of 4:1 in the cultivating medium. The completion of the formation of cell wall by the synthesis of the amorphous mannan-protein cell wall component was inhibited at a glucose to 2DG ratio of about 20:1. The inhibition could be reversed by increasing the glucose to 2DG ratio in the nutrient medium. No incorporation of 2DG into fibrillar glucan cell wall component was observed.
Acidaminococcus
gen. n.,
Acidaminococcus fermentans
sp. n., Anaerobic Gram-negative Diplococci Using Amino Acids as the Sole Energy Source for Growth
Authors: Rogosa Morrison
Published: January 2020

Acidaminococcus
gen. n. and the type species
Acidaminococcus fermentans
sp. n. were described. Amino acids, of which glutamic acid is the most important, could serve as the sole energy source for growth. Acetic and butyric acids and CO
2
were produced; propionic acid and hydrogen were not produced. Amino acid media supporting growth and the amino acid and vitamin requirements were described. Glucose was frequently not fermented or was weakly catabolized. Derivative products from glucose autoclaved in media, but not glucose itself, stimulated or were required for growth in amino acid media. A wide range of polyols and carbohydrates were not attacked. Lactate, fumarate, malate, succinate, citrate, and pyruvate were not used as energy sources for growth. Pyruvate completely suppressed growth. Cytochrome oxidase and benzidine reactions were negative; catalase, indole, acetyl methyl carbinol, and H
2
S were not produced; nitrate and sulfonthalein indicators were not reduced; ammonia was produced; gelatin liquefaction was negative or slow and partial; vancomycin (7.5 μg/ml) was resisted.
Acidaminococcus
was different from
Veillonella
in morphology, serology, nutrition, utilization of substrates, and accumulation of products in media supporting growth;
Acidaminococcus
resembled
Peptococcus
in utilization of glutamic acid and accumulation of similar products, but the two genera differed in morphology, gram reaction, serology, guanine plus cytosine content of deoxyribonucleic acid, and nutrition.
Localization and Properties of Enzymes Involved with Electron Transport Activity in Mycobacteria
Authors: Cesari Italo M. , Rieber Manuel , Imaeda Tamotsu
Published: January 2020

A study of the subcellular localization of the nicotinamide adenine dinucleotide (NADH)-3-(4, 3-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) oxido-reductase systems in
Mycobacterium
was presented. Evidence based on starch gel electrophoresis and different responses of the subcellular fractions to heat inactivation suggested the existence of more than one enzyme responsible for the NADH-MTT oxido-reductase activity. One type of activity was found in the membrane-mesosome fraction which contained labile and electrophoretically non-migrating enzymes. Another type of activity was also detected in the soluble fraction which on starch gel electrophoresis exhibited 4 bands of activity, two of which showed heat resistance.
Kinetic and Morphological Observations on
Saccharomyces cerevisiae
During Spheroplast Formation
Authors: Darling Sven , Theilade Jørgen , Birch-Andersen Aksel
Published: January 2020

A strain of
Saccharomyces cerevisiae
which produced elongated cells under our growth conditions was investigated. By digestion of the cell walls with snail enzyme, the cells became spheroplasts after a transient state which we termed “prospheroplast.” The prospheroplast could be lysed like the spheroplast, but it retained the shape of the original yeast cell if osmotically protected. Prospheroplasts and spheroplasts were prepared, and thin sections of samples taken throughout the process of wall removal were studied in the electron microscope, at regular intervals up to the time of complete conversion to spheroplasts. In addition, cell wall remnants recovered from spheroplast preparations were shadow cast for electron microscopy. This material revealed structures resembling bud scars with attached membranous matter. The kinetic studies showed that after a certain period of time all cells were transformed into prospheroplasts, whereas spheroplast formation started later, depending on the enzyme concentration. In sections, the prospheroplasts appeared to be formed by detachment of the cell walls. Both the prospheroplasts and the spheroplasts showed asymmetric cytoplasmic membranes in which the outer leaflets appeared coated with a dense fibrillar layer. The experiments suggest that, after enzyme digestion, the cytoplasmic membrane retains a coating which is rigid in the prospheroplast but which loses rigidity when the cell is transformed into a spheroplast.
Incomplete Bacteriophage-like Particles in Ultraviolet-irradiatedHaemophilus
Authors: Stachura Irene , Mckinley Franklin W. , Leidy Grace , Alexander Hattie E.
Published: January 2020

Incomplete phagelike particles were found in competent and incompetent cells ofHaemophilus influenzaeRd(transformable) lysed after exposure to ultraviolet radiation.
New Immunotype Schema for
Pseudomonas aeruginosa
Based on Protective Antigens
Authors: Fisher M. W. , Devlin H. B. , Gnabasik F. J.
Published: January 2020

The development of an antigen schema for
Pseudomonas aeruginosa
based on challenge protection in mice as distinguished from serological tests in vitro was described. For 342 cultures, seven groups of cross-protective homogeneity were defined.
Total Synthesis of Acetate from CO
2
II. Purification and Properties of Formyltetrahydrofolate Synthetase from
Clostridium thermoaceticum
Authors: Sun Albert Y. , Ljungdahl Lars , Wood Harland G.
Published: January 2020

Formyltetrahydrofolate synthetase from
Clostridium thermoaceticum
had optimal activity at 55 to 60 C.
K
m
values were: adenosine triphosphate (ATP), 6.25 × 10
−4
m
; formate, 1.67 × 10
−3
m
; and tetrahydrofolate, 1.00 × 10
−3
m
; at
p
H 8.0. There was a requirement for divalent metals and specifically for ATP.
Role of Phosphoenolpyruvate Carboxylation in
Acetobacter xylinum
Authors: Benziman Moshe
Published: January 2020

Glucose-grown cells of
Acetobacter xylinum
oxidized acetate only when the reaction mixture was supplemented with catalytic quantities of glucose or intermediates of the citrate cycle. Extracts, prepared by sonic treatment, catalyzed the formation of oxalacetate when incubated with phosphoenolpyruvate (PEP) and bicarbonate. Oxalacetate was not formed in the presence of pyruvate plus adenosine triphosphate. The ability to promote carboxylation of PEP was lower in succinate-grown cells than in glucose-grown cells. PEP carboxylase, partially purified from extracts by ammonium sulfate fractionation, catalyzed the stoichiometric formation of oxalacetate and inorganic phosphate from PEP and bicarbonate. The enzyme was not affected by acetyl-coenzyme A or inorganic phosphate. It was inhibited by adenosine diphosphate in a manner competitive with PEP (
K
1
= 1.3 m
m
) and by dicarboxylic acids of the citrate cycle; of these, succinate was the most potent inhibitor. It is suggested that the physiological role of PEP carboxylase in
A. xylinum
is to affect the net formation of C
4
acids from C
3
precursors, which are essential for the maintainance of the citrate cycle during growth on glucose. The relationship of PEP carboxylase to other enzyme systems metabolizing PEP and oxalacetate in
A. xylinum
is discussed.
Effect of Isomeric
cis
-Octadecenoic Acids on the Growth of
Leptospira interrogans
Serotype
patoc
Authors: Jenkin H. M. , Anderson L. E. , Holman R. T. , Ismail I. A. , Gunstone F. D.
Published: January 2020

Leptospira interrogans
serotype
patoc
exhibited an increasing growth response when cultivated in media containing from 50 to 250 μg of sodium oleate per ml. Leptospiral growth in the presence of 250 μg of sodium oleate per ml was as good as that in the basal medium which contained 700 μg of oleic acid (in Tween 80) per ml. When positional isomers of oleic acid (9-octadecenoic acid) were present at a concentration of 200 μg/ml, the 2- and 8-isomers were not readily utilized, whereas the 3-, 4-, 6-, 11-, 15-, and 16-isomers gave a growth response equivalent to that of oleic acid, i.e., the 9-isomer. The 5-, 7-, 10-, 12-, 13-, 14-, and 17-isomers of octadecenoic acid induced growth responses which differed in magnitude but were intermediate to those of 2-18:1 and 3-18:1. When 200 μg of either 2- or 3-octadecenoic acid per ml was added in addition to 200 μg of 9-18:1 alone; 400 μg of 9-18:1 alone per ml inhibited growth of this organism. The growth response of leptospira to octadecenoic acids differed from that of mammalian cells, suggesting the presence of different enzymes in the two systems for the utilization of these substrates.
Relationship of Hydrogen Peroxide Production by
Mycoplasma pulmonis
to Virulence for Catalase-deficient Mice
Authors: Brennan Patricia C. , Feinstein Robert N.
Published: January 2020

Mycoplasma pulmonis
, an etiological agent of murine pneumonia, produced about 0.065 μmoles of hydrogen peroxide (H
2
O
2
) per hr per 10
10
colony-forming units. When glucose was present at a concentration of 0.01
m
, H
2
O
2
production was increased by 50%. To determine if H
2
O
2
production by
M. pulmonis
could be correlated with virulence, normal, acatalasemic, and acatalatic mice were infected with the organism. Three days after infection with
M. pulmonis
significantly more acatalatic mice had pneumonia than did normal or acatalasemic mice. The pneumonia in acatalatic mice was also more severe than in the other two groups. Five days after infection, pneumonia in the acatalatic mice was resolved, whereas normal mice were severely affected. The presence of pneumonia and the severity were correlated with the recovery of
M. pulmonis
from the lesions. In vitro studies of the effect of catalase on
M. pulmonis
showed that exogenously supplied catalase stimulated the growth of
M. pulmonis
at 37 C and prolonged its survival at 25 C. Hemolysis of sheep blood, guinea pig blood, rabbit blood, and normal and acatalasemic mouse blood by
M. pulmonis
was inversely related to the catalase activity of the erythrocytes. These findings suggest that H
2
O
2
secretion contributes to the virulence of
M. pulmonis
and to the death of the microorganism in the absence of host catalase.