bluuebunny/crossref_metadata_2025 huggingface dataset:
Inducible Glutamate Transport in Mycobacteria and Its Relation to Glutamate Oxidation
Authors: Lyon Richard H. , Rogers Palmer , Hall Wendell H. , Lichstein Herman C.
Published: January 2020

Washed-cell preparations of
Mycobacterium tuberculosis
strain H37Ra and
M. smegmatis
607 grown in Sauton's medium demonstrated a lag in glutamate oxidation. Washed-cell preparations of
M. fortuitum
and
M. phlei
oxidized glutamate immediately and in a linear fashion. Glutamate was oxidized without a lag by washed cells of
M. tuberculosis
H37Ra and
M. smegmatis
607 harvested from a modified medium containing glutamate. Chloramphenicol inhibited the oxidation of glutamate by washed cells grown in the absence of glutamate. These findings suggested the induction of either an enzyme system for glutamate oxidation or a glutamate transport system. The activity of glutamic dehydrogenase was not significantly greater in extracts prepared from cells grown with glutamate. However, the initial rate of glutamate uptake by induced cells was three to four times higher than in noninduced cells. The induction of the glutamate transport system in
M. tuberculosis
H37Ra and
M. smegmatis
607 was shown to parallel the induction of glutamate oxidation. After a 60-min lag, the inducible glutamate transport system appeared. Chloramphenicol prevented the induction of glutamate uptake, although the antibiotic had no effect on glutamate uptake by previously induced cells. Some of the properties of this glutamate uptake system are described.
Group Q Streptococci I. Ecology, Serology, Physiology, and Relationship to Established Enterococci
Authors: Nowlan Sandra Simpson , Deibel R. H.
Published: January 2020

The group Q streptococci possess unique serological and physiological characteristics which differentiate them from established enterococci. The group Q antigen was not demonstrable in all strains; however, all possessed the group D antigen. All group Q strains were physiologically similar regardless of whether or not they possessed the group Q antigen. These strains differed from the established enterococcal species, as they neither hydrolyzed arginine nor initiated growth in 1.0% methylene blue-milk. They also differed radically in the fermentation of various carbohydrates, especially the polyhydric sugar alcohols. The results indicate that the group Q streptococci constitute a unique taxonomic entity; the species designation
Streptococcus avium
sp. n. is suggested, owing to their characteristic occurrence in chicken fecal specimens.
Identification of Fatty Acids and Aliphatic Hydrocarbons in
Sarcina lutea
by Gas Chromatography and Combined Gas Chromatography-Mass Spectrometry
Authors: Tornabene T. G. , Gelpi E. , Oró J.
Published: January 2020

The composition and nature of the fatty acids and hydrocarbons of
Sarcina lutea
were elucidated by gas chromatography and by combined gas chromatography-mass spectrometry. The distribution of fatty acids found in
S. lutea
showed two families of pairs, or dyads, of saturated monocarboxylic acids (C12–C18) with and without methyl branching. These pairs of fatty acids showed a pattern of iso and anteiso structures for C13, C15, and C17, and iso and normal structures for C12, C14, and C16. Only the C18 showed unsaturation. The distribution of hydrocarbons in the range C22–C29 showed two families of tetrads of unsaturated aliphatic hydrocarbons all showing methyl branching. Each tetrad was composed of four isomers identified as two iso olefins and two anteiso olefins. The only difference between the tetrads pertaining to different families was found in the relative gas chromatographic retention times of the last two components of each group.
Fatty Acid and Aliphatic Hydrocarbon Composition of
Sarcina lutea
Grown in Three Different Media
Authors: Tornabene T. G. , Bennett E. O. , Oró J.
Published: January 2020

Sarcina lutea
was grown in Trypticase Soy Broth, Nutrient Broth, and a chemically defined medium. Gas chromatographic analysis of lipid components demonstrated that the composition of the medium had an effect on the relative per cent composition of the aliphatic hydrocarbons and fatty acids present in the cells. The branched olefinic hydrocarbons from the organisms grown in Trypticase Soy Broth showed no predominance or only a slight predominance of odd-numbered carbon chains, whereas the hydrocarbons from cells grown in the other two media showed an obvious predominance of odd-numbered carbon chains. The monocarboxylic fatty acid content and distribution showed only minor differences, with all normal saturated fatty acids present in relatively small quantities for cells grown in Nutrient Broth and in a chemically defined medium.
Studies of Intestinal Microflora VI. Effect of X Irradiation on the Fecal Microflora of the Rat
Authors: Klainer Albert S. , Gorbach Sherwood , Weinstein Louis
Published: January 2020

The effect of sublethal, midlethal, and lethal doses of total-body X irradiation on the fecal microbial population of the rat was studied. No changes were observed in animals receiving sublethal doses of X ray. Midlethal and lethal doses produced an increase in the numbers of fecal coliforms, staphylococci, streptococci, and fungi; these changes were transient in rats that survived, but were more marked and persisted during life in those that died. The possible role of these alterations in intestinal microflora in post-irradiation infection and in death is discussed.
Role for the Female in Bacterial Conjugation in
Escherichia coli
Authors: Freifelder David
Published: January 2020

Hfr and F′ Lac male strains of
Escherichia coli
were mated with purine-requiring females which had been starved for purine. These females formed mating pairs with the males. However, a mating in the absence of purine markedly reduced the yield of recombinants. Transfer of F′ Lac or of λ prophage also occurred infrequently. It was concluded that deoxyribonucleic acid transfer from male to female requires some, as yet unknown, function of the female.
Basal Organelles of Bacterial Flagella
Authors: Cohen-Bazire Germaine , London Jack
Published: January 2020

Liberated by enzymatic lysis of the cells, the flagella ofRhodospirillum rubrum, R. molischianum, andR. fulvumall have a similar structure. The hook at the base of the flagellum is connected by a short, narrow collar to a paired disc in the basal organelle. This paired disc is in turn connected to a second paired disc. The disposition of flagella to which fragments of the cell membrane still adhere suggests that the narrow collar at the base of the hook traverses both the wall and the membrane, and that the upper pair of discs in the basal organelle lies just beneath the surface of the membrane.
Comparative Study of the Cell Walls of the Yeastlike and Mycelial Phases ofHistoplasma capsulatum
Authors: Domer Judith E. , Hamilton James G. , Harkin James C.
Published: January 2020

Cell walls were prepared from the yeastlike and mycelial phases (YP and MP) ofHistoplasma capsulatumand fromSaccharomyces cerevisiaeby mechanical disruption and washing. Lipids were extracted with methanol-ether, chloroform, and acidified methanol:ether; a final extraction was made with ethylenediamine. The lipid contents ofH. capsulatumYP and MP walls were about the same. Qualitative and quantitative analyses were made of the products obtained from treatment of the cell walls, or fractions from them, with weak acid or with enzymatic preparations containing glucanase and chitinase activities. YP walls contained much larger quantities of chitin and smaller quantities of mannose and amino acids than the MP walls.H. capsulatumMP was shown to resembleS. cerevisiaeby low chitin content and by the presence of a mannose polymer, soluble in ethylenediamine and water.H. capsulatumMP chitin appeared to be intimately associated with glucose in the wall, since enzymatic hydrolysis of the residue after mild acid hydrolysis of cell walls or fractions from them resulted in the release of glucose and acetylglucosamine; only acetylglucosamine was released from YP walls with such treatment. By electron microscopic observations, the unextracted MP cell walls were much thinner than the YP, and neither wall appeared laminated.
Biosynthesis of α-Isopropylmalic and Citric Acids in
Acetobacter suboxydans
Authors: Maragoudakis Michael E. , Strassman Murray
Published: January 2020

Cell-free extracts of
Acetobacter suboxydans
were prepared which were capable of condensing α-ketoisovalerate with
14
C-labeled acetyl-coenzyme A to yield
14
C-labeled α-isopropylmalate. The product of the reaction was isolated by paper and column chromatography and was characterized by recrystallization with synthetic α-isopropylmalic acid to constant specific radioactivity. The formation of α-isopropylmalate by extracts of
A. suboxydans
plus the ability of the organism to grow in a simple glucose-glycerol medium containing glutamic acid as the only amino acid indicate that the pathway for leucine biosynthesis shown to exist in yeast and
Salmonella typhimurium
also occurs in
A. suboxydans
. As a comparison, the condensation of oxalacetate and (
14
C) acetyl-coenzyme A to yield (
14
C) citric acid was shown, by similar means, to occur in
A. suboxydans
. This is of interest since the existence of this classical condensing enzyme has hitherto not been demonstrated in this organism. This reaction was further demonstrated in cell-free extracts of
A. suboxydans
by means of a spectrophotometric assay at 232 mμ which measured the cleavage of the carbon-sulfur bond of acetyl-coenzyme A in the presence of oxalacetate. Comparison of the specific activities of crude cell-free extracts indicated a much more extensive occurrence of this reaction in yeast than in
A. suboxydans
.
Characterization of Enterobacteria by Starch-Gel Electrophoresis of Glucose-6-Phosphate Dehydrogenase and Phosphogluconate Dehydrogenase
Authors: Bowman James E. , Brubaker Robert R. , Frischer Henri , Carson Paul E.
Published: January 2020

Specific activities and electrophoretic mobilities of glucose-6-phosphate dehydrogenase and phosphogluconate dehydrogenase were determined in 38 isolates of the family
Enterobacteriaceae
and in 10 isolates of the related
Pasteurella
. The deficiency of glucose-6-phosphate dehydrogenase in
P. pestis
was verified. Enzymes obtained from different strains of the same species exhibited an unexpected degree of heterogeneity. For example, 8 and 11 apparent variants of glucose-6-phosphate dehydrogenase and phosphogluconate dehydrogenase, respectively, were found in 14 strains of
Escherichia coli
. Although similar frequencies of heterogeneity were noted in 7 strains of
P. pseudotuberculosis
, 5 species of
Shigella
, and 8 species of
Salmonella
, differences in mobility were generally small in comparison with those observed between strains of
E. coli
. Values obtained for the pasteurellae, shigellae, and salmonellae, thus fell within narrow ranges that may prove typical for the genera. However, most of these ranges, as well as many values observed for single species of other genera, were overlapped by the wide range recorded for
E. coli
. The significance of this observation was discussed with respect to the relative age and taxonomic position of the organisms in question. The method could be used to distinguish between most wild-type strains of the same species and should thus facilitate investigations of genetic transfer and epidemiology.
Comparative Studies with Three Antibiotics Binding to Deoxyribonucleic Acid
Authors: Reusser Fritz , Bhuyan Bijoy K.
Published: January 2020

The effects of the three antibiotics U-12,241, nogalamycin, and U-20,661 on (i) deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) synthesis in KB cell cultures and cell-free systems of bacterial and mammalian origin and on (ii) oxidative phosphorylation in rat liver mitochondria were compared. Nogalamycin and U-12,241 inhibited RNA synthesis more strongly than DNA synthesis in all test systems. Antibiotic U-20,661 inhibited DNA and RNA synthesis equally in whole mammalian cells and their corresponding cell-free systems. The RNA polymerase from
Escherichia coli
, however, was at least 100 times more sensitive to U-20,661 than was the DNA polymerase. U-12,241 caused significant uncoupling of oxidative phosphorylation in mitochondria.
Tetanus Toxin and Antigenic Derivatives II. Effect of Protein and Formaldehyde Concentration on Toxoid Formation
Authors: Murphy Samuel G.
Published: January 2020

Tetanus toxoid formation was examined under varying conditions. Products of the reaction depended upon the concentration of both formaldehyde and toxin. High concentrations of protein and formaldehyde favored the formation of large polymers, whereas low concentrations yielded smaller polymers and monomer. The monomer had an observed
S
value of 7.1, whereas the polymers ranged from 10.1
S
to 110
S
. The cross-linking between toxin molecules to form toxoid polymers appeared to be random.
Preliminary Studies of Some Physiological Properties of
Torula jeanselmei
Authors: Wang C. J. K. , Brownell Sandra
Published: January 2020

The morphological characteristics of pathogenic and saprophytic strains of
Torula jeanselmei
(Fungi Imperfecti) are indistinguishable. Some basic physiological properties of
T. jeanselmei
were investigated in the hope of separating the human pathogenic strain from common saprophytes in a clinical laboratory. Nitrogen and carbon assimilation tests were not useful for distinguishing the pathogen, since all strains, pathogenic and saprophytic, were able to assimilate nitrogen from ammonium, nitrate, and nitrite sources, and all were able to utilize glucose, fructose, galactose, cellobiose, lactose, glycerol, and starch. It appeared that temperature range for growth might be useful in the identification of the pathogen. All pathogenic strains grew well at 37 C but poorly at 10 C; in contrast, all saprophytes could grow at 10 C but were unable to grow at 37 C (with two exceptions).
Antibiotic Treatment of Anthrax Infection in Mice
Authors: Jones William I. , Klein Frederick , Lincoln Ralph E. , Walker Jerry S. , Mahlandt Bill G. , Dobbs James P.
Published: January 2020

Quantitative measurements of mean time to death, percentage of survivors, and viable cell populations in the whole body were employed to determine the effects of penicillin, dihydrostreptomycin, chlortetracycline, oxytetracycline, chloramphenicol, and antiserum on the course of anthrax infection in mice. By all parameters tested, penicillin and dihydrostreptomycin were most effective in the treatment of the disease. Therapy initiated in the later stages of the disease was more effective than that initiated in the earlier stages. Quantitative studies indicated that it was more difficult to eliminate organisms from the kidney than from any other organ or tissue. These measurements for the evaluation of antibiotic therapy are suggested for the study of other bacterial diseases.
Inhibition of the Lysis of Fungi by Melanins
Authors: Kuo M.-J. , Alexander M.
Published: January 2020

Evidence is presented that the resistance of
Aspergillus nidulans
hyphae to lysis by a β-(1→3) glucanase-chitinase mixture results from the presence of melanin in the fungal walls. The resistance of the walls to digestion was directly correlated with the melanin content of the mycelium. A melanin-less mutant of
A. nidulans
was highly susceptible to hydrolysis by the enzyme mixture. Preincubation of a synthetic melanin with the glucanase, chitinase, and a protease, before addition of the substrate, resulted in a marked inhibition of the rate of substrate hydrolysis. Melanin also appeared to combine with and protect at least certain substrates from decomposition, as indicated by the direct relationship between the extent of inhibition of casein hydrolysis by a bacterial protease and the length of time the protein was incubated with the melanin prior to addition of the enzyme. Melanin was found to be highly resistant to microbial degradation, a likely requirement for the polyaromatic to be effective in protecting fungal structures from lysis or decomposition by natural communities of microorganisms.
Linkage and Segregation of Unselected Markers in Matings ofNocardia erythropoliswithNocardia canicruria
Authors: Brownell George H. , Adams James N.
Published: January 2020

The segregation of unselected genes expressing resistance or susceptibility to acriflavine, erythromycin, streptomycin, and tetracycline was analyzed in selected prototrophic recombinants resulting from matings ofNocardia erythropolisandN. canicruria. The organisms were shown to be functionally haploid and appeared to contain not more than one genome. It was postulated that all observed genes were present in a linear linkage group. The ordering of the genes inN. erythropoliswas:tetB10 eryB9 his-3 purA1 acr-2 strA1(respectively, resistance to tetracycline and erythromycin, deficiency for histidine and for purine, and resistance to acriflavine and streptomycin). The ordering of the genes inN. canicruriawas:purB2 tetA9 eryA7 acr-11 strB2(respectively, deficiency for purine, and resistance to tetracycline, erythromycin, acriflavine, and streptomycin). Excluding the genes for acriflavine resistance,acr-2andacr-11, resistance loci inN. erythropoliswere not allelic to and showed lateral displacement from genes controlling phenotypically similar resistance inN. canicruria. Evidence for some lack of homology betweenN. erythropolisandN. canicruriagenomes was found. Recombination phenomena between the nocardial species was postulated to occur as a result of formation of a heterogenomic zygote in which new combinations were produced. Production of selectable, haploid recombinants was ascribed to subsequent haploidization of the zygote.
Decomposition of Ribosomal Particles in
Escherichia coli
treated with Mitomycin C
Authors: Suzuki Hiromi , Kilgore Wendell W.
Published: January 2020

Exposure of cells of
Escherichia coli
to mitomycin C (5 μg/ml) resulted in a marked change in the sedimentation profiles of the cell-free extracts, indicating a specific decomposition of ribosomal particles. When the extracts were prepared in the presence of 0.01
m
Mg
++
and analyzed by sucrose density gradient centrifugations, the 100
S
fraction disappeared rapidly from the treated cells. The 70
S
ribosomes were also degraded, but more slowly, with a concomitant accumulation of a fraction having a sedimentation coefficient of about 50
S
. However, decomposition of the 70
S
ribosomes was preceded by an almost complete loss of the 50
S
ribosomal subunits, as revealed by sedimentation analyses in the presence of 10
−4
m
Mg
++
. Synthesis of the ribosomes in the treated cells was also suppressed, being demonstrated by a lower incorporation of uracil-
2
-
14
C
into the ribosomal fractions. However, the change in the ribosomal profile in the treated cells apparently resulted from the decomposition of pre-existing ribosomes, rather than from the inhibition of the net synthesis of ribosomes. Sedimentation analyses and chromatography of the nucleic acids extracted from the treated cells indicated extensive but delayed degradation of the ribosomal ribonucleic acid (RNA), but not of the soluble RNA or deoxyribonucleic acid fractions. Altered structure of the ribosomes in the treated cells was also indicated by their lower melting temperature, broadened thermal profile, higher electrophoretic mobility, and extreme sensitivity to ribonuclease treatment, compared with normal ribosomes. The synthesis of messenger RNA was inhibited progressively with time in the treated cells.
Inhibition of
Escherichia coli
B by Homoarginine
Authors: Peyru Graciela M. , Maas Werner K.
Published: January 2020

Homoarginine inhibits the growth of
Escherichia coli
B, but not of
E. coli
K-12. These two strains also differ in regard to repressibility of the arginine-forming enzymes. In K-12, arginine acts as a repressor whereas in B it does not. The latter difference is determined by different alleles of a regulator gene,
arg
R. In K-12 × B crosses, it was shown that the genetic determinant for homoarginine sensitivity is closely linked to or identical with
arg
R. Homoarginine-resistant mutants of B were isolated. The biochemical mechanism of homoarginine inhibition is not known. However, whether or not a strain is sensitive to homoarginine seems to depend on the intracellular level of arginine. In B this level is relatively low and inflexible as a result of the action of a repressor whose formation is determined by the B-specific allele of
arg
R.
Micromorphology ofCryptococcus neoformans
Authors: Edwards Mercedes R. , Gordon Morris A. , Lapa Edward W. , Ghiorse William C.
Published: January 2020

Fine details of the internal and external morphology ofCryptococcus neoformansas seen in ultrathin sections are described and illustrated with electron micrographs. The capsule characteristic of this species contained microfibrils (30 to 40 A in diameter) that appeared to radiate from the cell wall and to coil and intertwine in various directions. These thin, uniformly structured, electron-dense filaments are believed to represent complex polysaccharide molecules. The internal morphology ofC. neoformanswas in many ways similar to that of yeasts studied by other authors. The cell was uninucleate with a single nucleolus. The nuclear envelope, a pair of unit membranes interrupted by pores, was typical of that found in eucaryotic organisms. Smooth endoplasmic reticulum, mitochondria, vacuoles, storage granules, and ribosomes were consistent features of the cytoplasm. In addition,C. neoformanspresented membranous organelles derived from the plasma membrane and comparable to bacterial mesosomes and mitochondria of an annulate type.
Regulation of Glutamine Synthetase VI. Interactions of Inhibitors for
Bacillus licheniformis
Glutamine Synthetase
Authors: Hubbard Jerry S. , Stadtman E. R.
Published: January 2020

The relationships of five feedback inhibitors for the
Bacillus licheniformis
glutamine synthetase were investigated. The inhibitors were distinguishable by differences in their competitive relationship for the substrates of the enzyme. Mixtures of
l
-glutamine and adenosine-5′-monophosphate (AMP) or histidine and AMP caused synergistic inhibition of glutamine synthesis. Histidine, alanine, and glycine acted antagonistically toward the
l
-glutamine inhibition. Alanine acted antagonistically toward the glycine and histidine inhibitions. Independence of inhibitory action was observed with the other pairs of effectors. Possible mechanisms by which the inhibitors may interact to control glutamine synthesis are discussed. The low rate of catalysis of the glutamyl transfer reaction by the
B. licheniformis
glutamine synthetase can be attributed to the fact that
l
-glutamine serves both as a substrate and an inhibitor for the enzyme. Effectors which act antagonistically toward the
l
-glutamine inhibition stimulated glutamotransferase activity. The stimulation was not observed when
d
-glutamine was used as substrate for the glutamyl transfer reaction.
Studies with Hydroxyurea VII. Hydroxyurea and the Synthesis of Functional Proteins
Authors: Rosenkranz Herbert S. , Winshell Elaine B. , Mednis Aiga , Carr Howard S. , Ellner Cornelia J.
Published: January 2020

Hydroxyurea affected neither the synthesis nor the degradation of bacterial messenger-ribonucleic acid. The proteins made by hydroxyurea-treated cells were structurally intact and fully functional. Since the expression of the lethal action of hydroxyurea requires active protein production, the data indicate that treated cells do not die as the result of the synthesis of abnormal proteins.
Metabolism of Pipecolic Acid in a
Pseudomonas
Species V. Pipecolate Oxidase and Dehydrogenase
Authors: Baginsky Marietta L. , Rodwell Victor W.
Published: January 2020

Oxidation of pipecolate to Δ
1
-piperideine-6-carboxylate is catalyzed by pipecolate oxidase, an inducible, membrane-bound dehydrogenase associated with the electron transport components of
Pseudomonas putida
P2. From the oxidase, we obtained a smaller particle containing flavine adenine dinucleotide (FAD) and cytochrome
b
, but no longer able to catalyze electron transfer to oxygen or to cytochrome
c
. Certain properties of this
l
-pipecolate dehydrogenase, an FAD-flavoprotein, are reported.
Mode of Action of Antibiotic U-24,544
Authors: Reusser Fritz
Published: January 2020

Antibiotic U-24,544, a new antibacterial agent, was found to be an effective uncoupler of phosphorylation associated with the oxidation of glutamate and succinate in rat liver mitochondria. Respiration was inhibited during glutamate oxidation but not during succinate oxidation. In a medium deficient in inorganic phosphate, the agent showed slight stimulation of mitochondrial glutamate oxidation. Mitochondrial swelling induced by inorganic phosphate was suppressed. The antibiotic inhibited protein, nucleic acid, and cell wall synthesis in
Mycobacterium avium
cells nearly equally without a predominant inhibition of any one of these macromolecular biosynthetic processes. Nucleic acid and polypeptide synthesis remained unaffected, but respiration was inhibited in cell-free bacterial systems. It was thus concluded that the antibiotic interfered primarily with the cellular energy-generating processes.
Mechanism of Bacterial Pyrite Oxidation
Authors: Silverman Melvin P.
Published: January 2020

The oxidation by
Ferrobacillus ferrooxidans
of untreated pyrite (FeS
2
) as well as HCl-pretreated pyrite (from which most of the acid-soluble iron species were removed) was studied manometrically. Oxygen uptake was linear during bacterial oxidation of untreated pyrite, whereas with HCl-pretreated pyrite both a decrease in oxygen uptake at 2 hr and nonlinear oxygen consumption were observed. Ferric sulfate added to HCl-pretreated pyrite restored approximately two-thirds of the decrease in total bacterial oxygen uptake and caused oxygen uptake to revert to nearly linear kinetics. Ferric sulfate also oxidized pyrite in the absence of bacteria and O
2
; recovery of ferric and ferrous ions was in excellent agreement with the reaction Fe
2
(SO
4
)
3
+ FeS
2
= 3FeSO
4
+ 2S, but the elemental sulfur produced was negligible. Neither H
2
S nor S
2
O
3
2−
was a product of the reaction. It is probable that two mechanisms of bacterial pyrite oxidation operate concurrently: the direct contact mechanism which requires physical contact between bacteria and pyrite particles for biological pyrite oxidation, and the indirect contact mechanism according to which the bacteria oxidize ferrous ions to the ferric state, thereby regenerating the ferric ions required for chemical oxidation of pyrite.
Homoaconitic Acid Accumulation by a Lysine-Requiring Yeast Mutant
Authors: Maragoudakis Michael E.
Published: January 2020

Homoaconitic acid, the second intermediate of the proposed pathway for lysine biosynthesis in yeast, is accumulated in the growth medium of a lysine-requiring mutant. This acid has been identified on paper and column chromatography by comparing it with authentic
cis
-homoaconitic acid. The infrared spectrum of the isolated material was identical with that of synthetic
cis
-homoaconitic acid. In addition, the chemical structure of the enzymatic product has been verified by degradation to glyoxylic and α-ketoglutaric acids after treatment with KMnO
4
and HIO
4
and by catalytic reduction to the saturated acid 1,2,4-butanetricarboxylic acid. The isolated homoaconitic acid was also identified as a substrate for a purified enzyme preparation of homoaconitase.
Genetics and Physiology of Colicin-tolerant Mutants of
Escherichia coli
Authors: de Zwaig Rosa Nagel , Luria S. E.
Published: January 2020

A series of colicin-tolerant (
tol
) mutants of
Escherichia coli
K-12, which adsorbed colicins but were not killed by them, were isolated and studied genetically and physiologically. Three major classes of mutants were found:
tol II
, tolerant to colicins A, E1, E2, E3, and K;
tol III
, tolerant to A, E2, E3, and K; and
tol VIII
, tolerant to E1 only. The sites of
tol II
and
tol III
mutations mapped near the
gal
region (gene order:
tol-gal-bio
) and were cotransduced with
gal
by P1. In heterozygous diploids,
tol
+
was dominant over
tol
;
tol II
and
tol III
gave full complementation. All the
tol
mutations that mapped near
gal
rendered the bacteria more fragile during growth and hypersensitive to deoxycholate and to ethylenediaminetetraacetic acid. The
tol VIII
mutation mapped between
str
and
his
. These mutants were extremely sensitive to deoxycholate and were also hypersensitive to methylene blue, acridines, and various other compounds. The sensitivity is attributed to increased uptake due to selective alteration of the permeability barrier. The colicin-tolerant mutations are interpreted as affecting some components of the cytoplasmic membrane which mediate between the adsorbed colicin molecules and the target sites of their biochemical effects in the bacterial cell.
Microcysts of the Cellular Slime Mold
Polysphondylium pallidum
II. Chemistry of the Microcyst Walls
Authors: Toama Mohamed A. , Raper Kenneth B.
Published: January 2020

Methods are described for obtaining large masses of myxamoebae, for inducing these to form microcysts, and for the isolation of the microcyst walls from other cell components. The walls were fractionated into two parts, one alkali-soluble, the other alkali insoluble. The alkali-insoluble fraction is a type of cellulose and constitutes 28% of the microcyst wall by weight. The alkali-soluble fraction contains a glycogenlike material, lipids, and proteins. A possible mechanism of microcyst wall synthesis is discussed.
Effect of Streptomycin Deprivation on Enzyme Synthesis in Streptomycin-Dependent
Escherichia coli
Authors: Goodman R. E. , Spotts Charles R.
Published: January 2020

During growth of streptomycin-dependent strains of
Escherichia coli
in the absence of streptomycin (deprived growth), both constitutive and inducible synthesis of β-galactosidase were preferentially inhibited. A similar preferential inhibition of constitutive and derepressed synthesis of alkaline phosphatase was observed. Catabolite repression accounted for part, but not all, of the inhibition of the inducible β-galactosidase synthesis. Serological experiments indicated that that part of the inhibition specificially associated with streptomycin deprivation was not a result of the production of altered β-galactosidase. It is suggested that during deprived growth the ribosomes of streptomycin-dependent bacteria become impaired in their ability to translate certain messages.
Drug Resistance of Enteric Bacteria XIII. Distribution of R Factors in
Escherichia coli
Strains Isolated from Livestock
Authors: Mitsuhashi Susumu , Hashimoto Hajime , Suzuki Kaname
Published: January 2020

Escherichia coli
strains isolated from 151 swine and 108 fowl, which were kept at the Animal Health Center, Maebashi, Japan, were surveyed for drug resistance and distribution of R factors. All of the swine and 38% of the fowl excreted
E. coli
strains resistant to tetracycline, chloramphenicol, streptomycin, and sulfanilamide, or certain combinations thereof. Among 278 resistant cultures isolated from swine, 13% were found to be resistant to one antibiotic, whereas 87% were resistant to more than one antibiotic. Among these resistant strains, 40% carried R factors which were transferable by the usual conjugal process. The resistance patterns of these R factors included 36% which were singly resistant and 64% which were multiply resistant. Among 54 resistant cultures isolated from fowl, 24% were singly resistant and 76% were multiply resistant. Of the resistant strains from fowl, 22% carried R factors. The resistance patterns of R factors included 50% of the singly resistant type and 50% which were multiply resistant. In spite of feeding with dairy products containing only tetracycline, a high incidence of multiple resistance was observed in the
E. coli
strains and the R factors isolated from these animals.
Preparation and Chemical Composition of the Cell Walls of Mature Infectious Dense Forms of Meningopneumonitis Organisms
Authors: Manire G. P. , Tamura Akira
Published: January 2020

Relatively large-scale production and purification of meningopneumonitis organisms was developed for chemical and immunological studies on cell walls of the infectious dense forms. By disruption of purified organisms with glass beads in a Mickle shaker, highly purified preparations of cell walls were obtained by sucrose density gradient centrifugation, enzyme digestion, and sodium dodecyl sulfate treatment. The dry-weight recovery of purified cell walls from intact organisms was about 13%. When
32
P-labeled preparations of cell walls were fractionated into acid-soluble, lipid, ribonucleic acid (RNA), deoxyribonucleic (DNA), and residual fractions, about 80% of the
32
P in cell wall preparations was recovered in the phospholipid fraction, which corresponded to about 3% of the total phospholipid in the intact organisms. About 7% of the
32
P in purified cell walls was recovered in the RNA and DNA fractions respectively, but this corresponds to only about 0.4% of the
32
P found in those fractions in intact organisms. From dry-weight determinations, it was calculated that the purified cell wall preparations contained only 0.6% total nucleic acids, and these are probably not true cell wall constituents. These cell walls contained 70 to 75% protein, corresponding to about 14% of the protein in intact organisms. Amino acid analysis of these protein showed the existence of all common amino acids, glucosamine, and galactosamine. However, no muramic acid was detected by the methods employed.
Preparation and Chemical Composition of the Cell Membranes of Developmental Reticulate Forms of Meningopneumonitis Organisms
Authors: Tamura Akira , Manire G. P.
Published: January 2020

The outer limiting membranes of developmental reticulate forms of the meningopneumonitis organism were purified by a combination of differential centrifugation, trypsin digestion, and sodium dodecyl sulfate treatment, and their physical and chemical properties were compared with those of outer envelopes of mature dense forms of this organism. Reticulate bodies were easily disrupted by short periods of sonic treatment and were lysed by trysin digestion, in contrast to the dense bodies which were resistant to these treatments. In electron micrographs, reticulate body membranes were seen as very thin, flattened structures, whereas dense-body envelopes showed folding rigid membranes. The results of chemical fractionation of
32
P-labeled purified preparations indicated that reticulate body membranes have smaller amounts of phospholipid, and are more dense than cell walls of the mature forms. The analysis of amino acid composition of reticulate body cell membranes showed that they do not contain cystine or methionine, both of which were found in cell walls of dense bodies. These results clearly show that there are significant differences in the chemical and physical properties of the outer envelopes of the developmental and mature forms of this organism.
Fine Structure of
Bacillus megaterium
During Synchronous Growth
Authors: Ellar D. J. , Lundgren D. G. , Slepecky R. A.
Published: January 2020

A fine-structure study of synchronously dividing
Bacillus megaterium
revealed the sequence of events involved in the division of the cell. First, a mesosome develops as a concentric fold of the plasma membrane at the site of septum formation. The mesosome contains membrane-bound vesicular structures, 300 to 500 A in diameter, plus a large membrane-bound structure, 2,000 A in diameter. These larger vesicles are peculiar to mesosomes in this stage of division and are not observed in the mesosomes involved in spore septum formation. The transverse septum originates within the mesosome and remains enclosed during its subsequent growth across the cell. An intimate association is observed between mesosome vesicles, mesosome membrane, and the growing edge of the transverse septum. Prior to completion of the septum, the membranes bounding the mesosome fuse, and further wall thickening occurs within the structure formed by this fusion. At this time, the septum only equals the parent cell wall in thickness. The doubling in thickness of the septum, which is required for the production of two normal daughter cell walls, occurs during a second phase of wall thickening, which is characterized by the appearance of a constriction at the base of the septum. As the constriction widens, the wall in this region thickens, forming the typical rounded poles of the daughter cells. Capsular synthesis at the poles occurs during this second phase of wall thickening. Throughout the division process, the nuclear material appears to be associated at one end with a mesosome at or near the pole of the cell and at the other end to the mesosome involved in septum formation. This association frequently takes the form of a stalklike extension of the mesosome penetrating into the chromatin fibrils.
Appendages of
Clostridium bifermentans
Spores
Authors: Pope Leodocia , Yolton Diane P. , Rode L. J.
Published: January 2020

Four distinct spore appendage types were detected in an electron microscope survey of 12 strains of
Clostridium bifermentans
. A smooth tubular appendage and a feather-like appendage are described in detail. In addition, hirsute tubular appendages and small pin-like appendages are depicted. Spores of four strains apparently lack appendages.
Distribution of Cytochrome
c
Peroxidase Activity in Wild-Type and Petite Cells of Bakers' Yeast Grown Aerobically and Anaerobically
Authors: Avers Charlotte J.
Published: January 2020

Studies of mitochondrial biogenesis in yeast have been hampered by a lack of suitable membrane markers in anaerobically grown cells subsequently grown in air. Cytochrome
c
peroxidase activity and subcellular location was studied to determine whether it would be a useful marker for an analysis of mitochondrial formation. Cytochemical tests revealed enzyme reaction product on all mitochondrial membranes in aerobically grown wild-type cells. Anaerobically grown wild-type and all petite cultures contained cytochrome
c
peroxidase cytochemical reaction deposits on abundant cytoplasmic membranes and on the few mitochondrial profiles which also were seen in the electron photomicrographs. Biochemical studies corroborated the cytochemistry because mitochondrial fractions were greatly enriched in cytochrome
c
peroxidase activity for aerobically grown wild-type cultures, but petite and anaerobically grown wild-type cultures showed higher enzyme activities in supernatant fractions than was present in the corresponding particulate fractions after differential centrifugation. Evidence from low-temperature microspectroscopy, spectrophotometric assays of mitochondrial enzyme activities, and electron microscopy showed mitochondrial formation during the time required for preparation and lysis of spheroplasts from anaerobically grown cultures. The data were interpreted as indicating that cytochrome
c
peroxidase was an oxygen-inducible enzyme, and that there was a developmental relationship between enzyme-reactive membranes of mitochondria and cytoplasm during the period of respiratory adaptation.
Mechanism for the Pyridoxal Neutralization of Isoniazid Action on
Mycobacterium tuberculosis
Authors: Beggs William H. , Jenne John W.
Published: January 2020

In Sauton's synthetic liquid medium, 10 μg of pyridoxal per ml completely protected
Mycobacterium tuberculosis
(H37R
a
) from the effects of a minimal inhibitory concentration of isoniazid (0.01 μg/ml).
14
C-labeled isoniazid was employed to study the nature of this protective effect. Uptake of the drug by cells in a Sauton environment containing 0.01 μg of
14
C-isoniazid per ml was inhibited 20 to 40% by 10 μg of pyridoxal per ml during the early hours of drug exposure. A stronger inhibition of uptake resulted when labeled isoniazid and pyridoxal were increased to 0.1 μg/ml and 50 to 100 μg/ml, respectively. Further studies revealed that certain Sauton nutrients are required to achieve this effect. When
l
-asparagine or salts (MgSO
4
and ferric ammonium citrate) or both were deleted from the menstruum, pyridoxal did not inhibit isoniazid incorporation by the tubercle bacilli. Pyridoxal also failed to inhibit uptake when (NH
4
)
2
SO
4
was substituted for
l
-asparagine. Growth experiments in Sauton's medium modified to contain (NH
4
)
2
SO
4
instead of
l
-asparagine were consistent with the latter finding. Pyridoxal did not prevent isoniazid growth inhibition in this medium. It is postulated that a large excess of pyridoxal in Sauton's medium protects tubercle bacilli from the effects of isoniazid through formation of an extracellular complex involving drug, vitamin, and certain medium constituents, thereby reducing the level of isoniazid available to the cells.
Effects of a Single Histoplasmin Skin Test on the Serological Diagnosis of Histoplasmosis
Authors: Kaufman Leo , Terry Robert T. , Schubert Joseph H. , McLaughlin David
Published: January 2020

Numerous reports have indicated that a single histoplasmin skin test may stimulate humoral antibodies to
Histoplasma capsulatum
antigens in histoplasmin-hypersensitive individuals. Although these investigations concur that antibody elevations are evoked, they vary in the reported degree of incidence and response induced, and they cast doubt on the interpretation of serological tests in the diagnosis of histoplasmosis. Histoplasmin-hypersensitive subjects (114) were bled prior to administration of the skin test, 2 days later, at the time this test was read, and 15 and 30 days after testing. No significant antibody titers were observed at 2 days. At 15- and 30-day intervals, only 17 (15%) of the subjects demonstrated circulating antibodies. All 17 showed agar gel bands; 5 demonstrated no complement-fixation (CF) titers, 10 produced CF antibodies ranging from 1:8 to 1:16, and 2 demonstrated titers of 1:32. The data suggest that skin testing does not interfere significantly with antibody levels in sera drawn approximately 2 days after administration of antigen. However, since titers as high as 1:32 were obtained at later intervals, such reactions should be evaluated cautiously and only after consideration of clinical findings.
In Vitro Acetylcholinesterase Inhibition by Type A Botulinum Toxin
Authors: Marshall R. , Quinn L. Y.
Published: January 2020

Type A botulinum toxin was studied for its ability to inhibit the action of acetyl-cholinesterase. The chromogenic substrate, indophenyl acetate, was used for assay of enzyme activity. Inhibition of enzyme function was detected through use of both 6.6 × 10
−6
mg (20
ld
50
) and 6.6 × 10
−10
mg (2 × 10
−3
ld
50
) of type A botulinal toxin. Control assays were performed by use of both homologous antitoxin and heterologous antitoxins (types B and E). Enzyme inhibition was effectively prevented by use of homologous antitoxin only. The inhibition noted was specific and reproducible for given substrate, enzyme, and toxin concentrations.
Host-Parasite Relationships in Experimental Airborne Tuberculosis II. Reproducible Infection by Means of an Inoculum Preserved at −70 C
Authors: Grover A. A. , Kim H. K. , Wiegeshaus E. H. , Smith D. W.
Published: January 2020

The use of an inoculum preserved at low temperature for the infection of guinea pigs by the respiratory route was evaluated. In a preliminary study with
Mycobacterium bovis
(BCG), some of the conditions required for maximal recovery of viable cells stored at low temperature were examined. Survival of BCG was decreased by rapid freezing to −70 C and by storage at −20 C, but there was no decrease when BCG was frozen slowly and stored at −70 C or −196 C. In a subsequent study, the effect of storage at −70 C on viability and infectivity of
M. tuberculosis
(H37Rv) was considered. There was no loss of viability of H37Rv cells suspended in Dubos broth and stored 1 year at −70 C. This suspension showed no loss of infectivity as assessed by the number of primary pulmonary lesions initiated in guinea pigs. Constant viability and infectivity of a suspension stored at low temperature assures the reproducibility of the amount of infection and facilitates comparisons between experiments. This advantage, as well as others, of storage at low temperature are discussed.
Preparation and Effect of Different Adjuvants on the Immunogenic Activity of Mycobacterial Ribosomal Fraction
Authors: Youmans Anne S. , Youmans Guy P.
Published: January 2020

Several emulsified and two nonemulsified incomplete adjuvants were examined for their adjuvant activity by use of mycobacterial ribosomal fractions as a substrate. A good adjuvant is defined as one which produces a high immunological response with the ribosomal fraction in mice to infection with virulent tubercle bacilli. Freund's incomplete adjuvant, consisting of Aquaphor and heavy mineral oil, and Arlacel A plus hexadecane were the best adjuvants tested. Aquaphor plus light mineral oil and Arlacel A plus 7-n-hexyloctadecane were not quite as effective. Peanut oil was not satisfactory when emulsified with either Aquaphor or Arlacel A. A moderate degree of immunity was produced in mice vaccinated with ribosomal fraction mixed with aluminum hydroxide gel. Sodium alginate mixed with ribosomal fraction produced a low degree of immunity only with the highest vaccinating dose. It was found that the effectiveness of the emulsified type of adjuvant depended upon the method of preparation. Careful standardization of technique to produce uniform and complete emulsification was essential for maximal adjuvant activity using minimal vaccinating doses. A rapid and practical method of preparing emulsified adjuvants is given. The mode of action of incomplete adjuvants as employed in these experiments is discussed, and it is thought that they acted primarily by protecting the ribosomes from being inactivated by host ribonuclease before they were engulfed by the macrophages.
Induced Phenotypic Resistance to Valine in
Mycobacterium pellegrino
Authors: Horvath Istvan , Szentirmai A. , Zsadanyi J.
Published: January 2020

Valine coordinately increases the levels of three of the enzymes participating in the biosynthesis of isoleucine and valine in
Mycobacterium pellegrino
. The amount of valine required for end-product induction depends on the condition of the cells. Isoleucine inhibits the effect of valine. Acetohydroxy acid synthetase, the enzyme catalyzing the first common step in the biosynthesis of valine and isoleucine, is inhibited by valine. The induction effect of valine appears to be due to its ability to inhibit the activity of this enzyme, thus causing isoleucine deficiency, which in turn leads to derepression. This conclusion is supported by the fact that valine, under certain conditions, inhibits growth.
Effects of
p
-Fluorophenylalanine and Chloramphenicol on Chemotaxis in
Escherichia coli
Authors: Fleming R. W. , Williams F. D. , Wailes K. A.
Published: January 2020

The effects of chloramphenicol and
p
-fluorophenylalanine (
p
-FPA) on growth, proportion of motile cells, average rate of motility, and the chemotactic response of a methionine auxotroph of
Escherichia coli
K-12 were studied. Kinetic studies revealed that the inhibition of chemotaxis by
p
-FPA can be explained by the effect on growth, proportion of motile cells, and average rate of motility rather than a selective inhibition of chemotaxis per se. The effect of chloramphenicol on chemotaxis could not be explained in terms of these characteristics. It is concluded that low concentrations of chloramphenicol, unlike
p
-FPA, selectively inhibit chemotaxis.
Initial Step in Catabolism of Glucose by the Meningopneumonitis Agent
Authors: Vender Joyce , Moulder James W.
Published: January 2020

The relative rates of catabolism of glucose and glucose-6-phosphate by intact-cell suspensions of the meningopneumonitis agent, a member of the psittacosis group (
Chlamydia
), and the properties of the hexokinase and glucose-6-phosphate dehydrogenase of these suspensions were investigated. It is proposed that the hexokinase is a host enzyme bound to the surface of the meningopneumonitis cell and that glucose-6-phosphate is the first substrate in the conversion of hexose to pentose to be attacked by enzymes synthesized by the meningopneumonitis agent.