bluuebunny/crossref_metadata_2025 huggingface dataset:
Control of Lysine Biosynthesis in Yeast by a Feedback Mechanism
Authors: Maragoudakis Michael E. , Holmes Helen , Strassman Murray
Published: January 2020

Homocitric acid (β-hydroxy-β-carboxyadipic acid; HC) is accumulated by a lysine-requiring yeast mutant when grown in a chemically defined medium, supplemented with limited amounts of lysine. A study of the formation of HC in relation to the depletion of lysine from the growth medium indicates that HC accumulated only when the concentration of lysine was low. The enzymatic formation of HC from α-ketoglutarate plus acetyl-coenzyme A in cell-free extracts of the same organism was also inhibited by lysine. The inhibitory effect of lysine on the formation of HC in both whole cells and cell-free extracts is indicative of the functional existence of a feedback control mechanism in the pathway for lysine biosynthesis in yeast.
Glucose Catabolism in
Micrococcus sodonensis
Authors: Perry Jerome J. , Evans James B.
Published: January 2020

The inability of
Micrococcus sodonensis
to grow on glucose as the sole source of carbon and energy was investigated. Estimation of pathways of glucose catabolism indicated that both the glycolytic and hexose monophosphate pathways are present in this organism. Comparative studies with
Escherichia coli
demonstrated that key enzymes for glucose catabolism were present in
M. sodonensis
in quantities equivalent to those of
E. coli
. The glucose-6-phosphate and 6-phosphogluconate dehydrogenases of
M. sodonensis
were nicotinamide adenine dinucleotide phosphate (NADP) specific, and glyceraldehyde-3-phosphate dehydrogenase was nicotinamide adenine dinucleotide specific. Transhydrogenase and reduced NADP oxidase were absent. Growth of the organism in the presence of glucose did not result in a repressed ability to oxidize tricarboxylic acid cycle intermediates, but these cells did have a decreased capacity for glucose degradation. The addition of substrates rich in growth-promoting substances, e.g., yeast extract, did not provide requisite nutrients for growth on glucose. Studies with
32
P suggest that
M. sodonensis
is incapable of synthesizing energy-rich phosphate compounds during the catabolism of glucose.
Bacterial Resistance to the Synergistic Antibiotics of the PA 114, Streptogramin, and Vernamycin Complexes
Authors: Ennis Herbert L.
Published: January 2020

A mutant of
Bacillus subtilis
was isolated that was resistant to the growth inhibitory activity of the synergistic antibiotics of the PA 114, streptogramin, and vernamycin complexes.
Escherichia coli
is naturally resistant to the action of these antibiotics. In both cases, it was shown that resistance was due to an inability of the bacteria to transport the antibiotics into the cell.
Serological Response of Rhesus Monkeys to
Histoplasma, Blastomyces
, and
Coccidioides
Antigens
Authors: Taylor Robert L.
Published: January 2020

Fifteen adult rhesus monkeys were inoculated with nonviable
Histoplasma capsulatum, Blastomyces dermatitidis
, or
Coccidioides immitis
. Antibody assays were made periodically during a 2-year period by use of a complement-fixation (CF) test employing four antigens and a latex-agglutination test. Selected sera were also studied in an immunodiffusion test and a coccidioidin-precipitin test. The serological patterns obtained with the anti-
Histoplasma
, anti-
Blastomyces
, and anti-
Coccidioides
monkey sera were comparable to those of sera from patients with diseases caused by the respective organisms. Rhesus monkeys should provide a good laboratory model for additional studies, including the influence of multiple antigenic stimuli on serologic response and patterns. Monkeys could also be used for the production of antisera required for studies to improve the specificity of the currently available CF antigens.
Structure and Composition of the Cell Wall of
Neurospora crassa
Authors: Manocha M. S. , Colvin J. Ross
Published: January 2020

The structure and composition of the cell walls of hyphae of
Neurospora crassa
were investigated by electron microscopy, chemical analysis, and X-ray diffraction both before and after progressive enzymatic degradation by snail gut enzymes, chitinase, and trypsin. The wall consists of two phases: randomly disposed skeletal microfibrils of chitin only and an amorphous matrix which contains both β-glucans and protein. The protein contains a high percentage of the amides of aspartic and glutamic acid but no hydroxy-proline or cysteine. A portion of this protein is a component of or is associated with a system of pores which is embedded in the matrix of the wall. These pores, 40 to 70 A in outside diameter, sometimes branch and seem to provide a three-dimensional network from one side of the wall to the other. They may be a general system of transport across the walls.
Cell Wall Changes During the Budding Process of
Paracoccidioides brasiliensis
and
Blastomyces dermatitidis
Authors: Carbonell Luis M.
Published: January 2020

The difference between the budding process of
Paracoccidioides brasiliensis
and
Blastomyces dermatitidis
is reported herein. A characteristic feature in
P. brasiliensis
is that the optical density of the cell wall increases at the site where budding begins and at the neck of the dividing cell, whereas
B. dermatitidis
does not undergo this alteration. The neck which is formed between the mother and daughter cell at the site of division is much wider in
B. dermatitidis
than in
P. brasiliensis
. The bud scar in
P. brasiliensis
appears as a truncated cone, the top of which is covered only by the inner layer of the cell wall; in comparison, in
B. dermatitidis
the bud scar exhibits a flattened surface covered by the cell wall. Both fungi show an increase in the number of mitochondria and infoldings of the cytoplasmic membrane at the site of separation, which indicates that at this site there is an increase of metabolic activity.
Differentiation of Pathogenic and Saprophytic Leptospires I. Growth at Low Temperatures
Authors: Johnson Russell C. , Harris Virginia G.
Published: January 2020

The minimal growth temperature of the pathogenic leptospires is between 13 and 15 C. The saprophytic leptospires have a minimal growth temperature between 5 and 10 C, or approximately 5 C below that of the pathogens. The capability of the saprophytic leptospires to grow at temperatures below those which allow the growth of the pathogenic leptospires provides a simple method of discrimination. With an inoculum yielding approximately 8 × 10
7
cells per ml in the test medium and an incubation temperature of 13 C, the saprophytic leptospires were easily differentiated from the pathogenic leptospires. All 13 saprophytic leptospires tested grew in the 10% rabbit serum medium at 13 C, whereas none of the 20 pathogens grew during the 30-day incubation period.
A
p
H 7 Buffer Devoid of Nitrogen, Sulfur, and Phosphorus for Use in Bacteriological Systems
Authors: Mallette M. F.
Published: January 2020

Apparent
p
K values were determined for a series of commercially available carboxylic acids in a search for a buffer suitable for bacterial studies at
p
H 7 in media free from nitrogen, sulfur, and phosphorus. Of the compounds possessing
p
K′ values near
p
H 7,3,6-endomethylene-1,2,3,6-tetrahydrophthalic acid (EMTA) was chosen as possessing suitable physical properties, cost, and purity for biological use.
Aerobacter aerogenes
and
Escherichia coli
grew normally in its presence but did not utilize it as a sole source and energy. Although good turbidimetric data could not be obtained,
Pseudomonas aeruginosa
responded in the same qualitative way. Therefore, EMTA promises to be useful in work on endogenous metabolism and in nutritional studies.
Studies of Intestinal Microflora VII. Effect of Diet and Fecal Microbial Flora on Survival of Animals Exposed to X Irradiation
Authors: Klainer Albert S. , Gorbach Sherwood , Weinstein Louis
Published: January 2020

Changes in the numbers and ratios of bacteria in the feces of rats were produced by administration of three different diets—grain, meat alone, and meat plus lactose. After significant alterations in the intestinal flora had developed, the animals were exposed to a midlethal dose of X irradiation (1,550 R). This treatment led to 100% deaths in rats in which the numbers of coliforms were increased by diet prior to irradiation. Changes in the numbers of lactobacilli appeared to play no role in determining the responses to X-ray exposure. When little or no change was produced by diet and when “normal” microflora was present, the fatality rate was reduced to 60%, and the rate of deaths was retarded when compared with that of the animals in which coliforms were increased.
Thermosensitive Replication of a Kanamycin Resistance Factor
Authors: Terawaki Yoshiro , Takayasu Hisao , Akiba Tomoichiro
Published: January 2020

A strain of
Proteus vulgaris
isolated from the urinary tract of a patient with postoperative pyelonephritis and resistant to sulfonamide, streptomycin, tetracycline, and kanamycin (KM) was found to transfer only KM resistance by cell-to-cell conjugation. The genetic determinant controlling the transferable KM resistance was considered to be an R factor and was designated R (KM). Successive transfer of KM resistance was demonstrated also from
Escherichia coli
20S0, which received the R (KM) factor, to other substrains of
E. coli
K-12 or
Salmonella typhimurium
LT-2. The transfer of the R (KM) factor was strongly affected by the temperature at which the mating culture was kept. The transfer frequency of R (KM) at 25 C was about 10
5
times higher than at 37 C. The R (KM) factor was spontaneously eliminated from the host bacterial cells when
P. vulgaris
was cultured at 42 C, but no elimination occurred at 25 C. This elimination of the R (KM) factor at elevated temperature was also observed when the R (KM) factor infected
E. coli
and
S. typhimurium
. On the other hand, a normal R factor could not be eliminated from the same
E. coli
host strain by cultivation at the higher temperature. We consider the thermosensitive transfer and the spontaneous elimination of the R (KM) factor at higher temperature to depend upon thermosensitive replication of the R (KM) factor.
Comparative Study of the Events Associated with Colicin Induction
Authors: Herschman Harvey R. , Helinski Donald R.
Published: January 2020

Colicinogenic factors ColI and ColV, which have been shown to behave as sex factors, could not be induced with mitomycin C. In contrast, the ColE
1
, ColE
2
, and ColE
3
factors, which do not exhibit any fertility factor characteristics, are inducible by this agent. The induced production of colicins E
1
, E
2
, and E
3
was accompanied by a loss in viability at a concentration of mitomycin C which was bacteriostatic to noncolicinogenic cells or to cells carrying the ColV or ColI factors. The loss in viability accompanying the mitomycin C induction of the ColE
1
, ColE
2
, or ColE
3
factors also occurred when colicin synthesis was blocked by chloramphenicol or amino acid starvation. However, chloramphenicol was able to block the loss of viability of a recipient cell after mitomycin C induction of a newly acquired Col factor if the antibiotic was present throughout the mating period. No detectable internal colicin or colicin precursor could be demonstrated during the lag period prior to the appearance of colicin outside the cell 20 to 30 min after the addition of mitomycin C. If chloramphenicol was present during the lag period following the addition of mitomycin C, colicin synthesis began immediately after the removal of these antibiotics. The synthesis of tryptophan synthetase and induced β-galactosidase proceeded normally throughout the lag period and well into the period of colicin production. Regulation of β-galactosidase synthesis did not seem to be profoundly affected during the lag period subsequent to mitomycin C addition. Induced colicin synthesis, like bacterial or induced prophage protein synthesis, was subject to inhibition by virulent phage infection.
Genetic Studies of Sulfadiazine-resistant and Methionine-requiringNeisseriaIsolated From Clinical Material
Authors: Catlin B. Wesley
Published: January 2020

Deoxyribonucleate (DNA) preparations were extracted fromNeisseria meningitidis(four isolates from spinal fluid and blood) andN. gonorrhoeaestrains, all of which were resistant to sulfadiazine upon primary isolation. These DNA preparations, together with others from in vitro mutants ofN. meningitidisandN. perflava, were examined in transformation tests by using as recipient a drug-susceptible strain ofN. meningitidis(Ne 15 Sul-s Met+) which was able to grow in a methionine-free defined medium. The sulfadiazine resistance typical of each donor was introduced into the uniform constitution of this recipient. Production ofp-aminobenzoic acid was not significantly altered thereby. Transformants elicited by DNA from theN. meningitidisclinical isolates were resistant to at least 200 μg of sulfadiazine/ml, and did not show a requirement for methionine (Sul-r Met+). DNA from six strains ofN. gonorrhoeae, which were isolated during the period of therapeutic use of sulfonamides, conveyed lower degrees of resistance and, invariably, a concurrent methionine requirement (Sul-r/Met−). The requirement of these transformants, and that of in vitro mutants selected on sulfadiazine-agar, was satisfied by methionine, but not by vitamin B12, homocysteine, cystathionine, homoserine, or cysteine. Sul-r Met+and Sul-r/Met−loci could coexist in the same genome, but were segregated during transformation. On the other hand, the dual Sul-r/Met−properties were not separated by recombination, but were eliminated together. DNA from various Sul-r/Met−clones tested against recipients having nonidentical Sul-r/Met−mutant sites yielded Sul-s Met+transformants. Themetlocus involved is genetically complex, and will be a valuable tool for studies of genetic fine structure of members ofNeisseria, and of genetic homology between species.
Electron Microscopy of the Combination of Antibodies with Flagellar Antigen and with a Pyocine
Authors: Goto Sachio , Homma J. Yusuru , Mudd Stuart
Published: January 2020

Micrographs are presented of antibodies in combination with flagella ofSalmonella typhiand with a phage-bound pyocine Rmc, which is supposed to be the tail of a defective bacteriophage fromPseudomonas aeruginosa. The pyocine preparation seems to offer advantages for the study of antibody-antigen complexes. Under the conditions of our experiments, the surfaces of the antigenic structures are saturated with antibody layers approximately 95 A in thickness, i.e., slightly less than half the accepted lengths of 7Santibody molecules. Our interpretation is that the antibody is attached by combining sites at the ends of the molecules to form loops along the surface of the antigenic structures.
Comparative Study of Ribosomal Ribonucleic Acid Cistrons in Enterobacteria and Myxobacteria
Authors: Moore Richard L. , McCarthy Brian J.
Published: January 2020

Deoxyribonucleic acid (DNA)-ribonucleic acid (RNA) hybrids are formed by
Escherichia coli
16
S
or 23
S
ribosomal RNA or pulse-labeled RNA with the DNA of various species of the
Enterobacteriaceae
. The relative extent of hybrid formation is always greater for ribosomal RNA. These DNA-RNA hybrids have been further characterized by their stability to increasing temperature, and, in every case, the stability of pulse-labeled RNA hybrids was lower than that of the corresponding ribosomal RNA hybrids, although 16
S
and 23
S
ribosomal RNA hybrids had very similar stabilities. Therefore, ribosomal RNA showed a greater degree of apparent conservation in base sequence than pulse-labeled or messenger RNA both in the extent of cross-reaction and in the stability of hybrid structures. Similar results were obtained with
Myxococcus xanthus
RNA. Since in this case the base composition of the pulse-labeled or messenger RNA is richer in guanine plus cytosine than ribosomal RNA, the higher cross-reaction of ribosomal RNA is more readily attributable to conservation of base sequence in these cistrons than to its base composition. Thus, the base sequence of ribosomal RNA cistrons of bacilli, enteric bacteria, and myxobacteria is conserved relative to those of the rest of the genomes. This conservation is, however, not absolute since the stability of heterologous ribosomal RNA hybrids is always lower than that of homologous hybrids.
Interaction of Colicins with Bacterial Cells III. Colicin-tolerant Mutations in
Escherichia coli
Authors: Nomura M. , Witten C.
Published: January 2020

Mutants that adsorb certain colicins without being killed, i.e., tolerant mutants (
tol
), were isolated from
Escherichia coli
K-12 strains. Selection was done either with colicin K or E2. Several groups of mutants showing different phenotypes were found, and some of them showed tolerance to both K and E colicins, which have different receptors. Many of these mutants mapped near
gal
. Typical mutants from group II, III, and IV were studied in more detail. The mutant loci were contransducible with
gal
by phage P1. The linkage order was deduced to be
tol-gal
-λ. In partially diploid strains, these mutant loci are recessive to wild-type alleles. Temperature-dependent conditionally tolerant mutants were also isolated. Two groups were found: the first was tolerant to E2 and E3 at 40 C, but sensitive at 30 C; the second was tolerant to E2 at 30 C, but sensitive at 40 C. Experiments done with these mutants suggest that these mutations affect the heat lability of some protein that is necessary for the response of cells to colicins. Conditionally lethal tolerant mutants were isolated which at 40 C were tolerant to E2 and E3 and could not grow, but which at 30 C were fully sensitive and grew normally. The mutation mapped near
malA
. The tolerance at 40 C is not due to a consequence of an inactivation of general cellular metabolism, but presumably is a cause of the subsequent inhibition of cellular growth. The results suggest that some protein components involved in the response to colicin are also vital to normal cellular growth.
Intragenic Mapping of Chemically Induced
ad-7
Mutants of
Schizosaccharomyces pombe
Authors: Loprieno Nicola
Published: January 2020

Thirty adenine-requiring
ad-7
mutants of
Schizosaccharomyces pombe
, induced by ethylmethanesulfonate, methyl-methanesulfonate, and hydroxylamine and exhibiting low spontaneous reversion frequencies, were located by intragenic recombination analysis. Their identification as
ad-7
mutants was assessed in relation to two previously mapped
ad-7
mutants. Each mutant was found to occupy a distinct mutational site; the smallest recombination fraction observed between the two closest mutational sites was of the order of 0.5 × 10
−6
.
Kinetics and Immunoglobulin Nature of the Antibody Response toMycobacterium tuberculosis
Authors: O'Connor J. E. , Snyder I. S.
Published: January 2020

Antibody production after injection ofMycobacterium tuberculosiswas studied by use of the single cell plaque assay technique. Maximal numbers of antibody-forming cells were found 9 days after a single injection ofM. tuberculosis, about 1 day before the appearance of maximal circulating antibody. Immunoelectrophoretic studies and 2-ME studies on 19Sand 7Sglobulin fractions obtained by gel filtration show that the hemagglutination and hemagglutination-lysis antibody activity is associated with 19Simmunoglobulin.
Nephelometric Assay of Bovine Antistaphylocoagulase Serum
Authors: Stutzenberger F. J. , Clemente C. L. San
Published: January 2020

A nephelometric assay of staphylococcal coagulase has been utilized to measure coagulase inhibition by bovine anticoagulase serum. Suitably diluted antisera produced maximal inhibition when incubated with purified coagulase atpH 7.3 in phosphate-buffered saline for 15 min at 22 C or 1 hr at 4 C. Neutralization of coagulase activity was measured as the reduction in the clotting rate of a fibrinogen-plasma substrate, and was directly proportional to the concentration of antiserum over a wide range of coagulase activity. A unit of anticoagulase was defined as the amount of inhibitor that neutralized one unit of coagulase. In addition to the heat-stable (56 C, 30 min) antibody contained in the crude γ-globulin fraction, a heat-labile, nondialyzable coagulase inhibitor was also detected in the sera from 15 of 16 randomly selected dairy cows.
Comparative Cell Wall Analyses of Morphological Forms Within the Genus
Actinomyces
Authors: Pine Leo , Boone Clarence J.
Published: January 2020

Comparative cell wall analyses were made of mycelial and smooth forms of
Actinomyces bovis
and
A. israelii
to determine the changes which occur in the cell wall composition concurrent with a change in morphology, and to evaluate cell wall analyses as a criterion for taxonomic identification within the genus
Actinomyces
. Cell walls of the spider forms of
A. boyis
had little or no aspartic acid and a high hexosamine concentration; cell walls of the smooth forms had a high aspartic acid content and low concentrations of hexosamine. Both forms had large amounts of glutamic acid, alanine, and lysine, as previously reported. A strain of
Actinomyces
, previously identified as
A. naeslundii
on the basis of morphology and aerobic growth characteristics, was found to have the basic cell wall composition of
A. israelii
. When transferred from the
Actinomyces
maintenance broth to a thioglycolate broth, the cells of this strain passed from a mycelial form through a transient filamentous morphology to become diphtheroidal with continued incubation. Concomitantly, the concentrations of glutamic acid relative to alanine decreased, and the hexosamine content increased. Variation in morphology within the species
A. israelii
and
A. bovis
could not be related to any mutual chemical change of their cell walls.
Influence of Cellular Factors on Immune Unresponsiveness Induced by
Klebsiella pneumoniae
Capsular Antigen
Authors: Wu William G. , Trice Karen L.
Published: January 2020

The mechanisms by which immune unresponsiveness (immune paralysis) develops are still uncertain. The present work was based on the assumption that this condition may be due to failure of certain activities of the macrophages. Data from passive transfer of such cells are interpreted as supporting this hypothesis. Purified capsular polysaccharide from type 2
Klebsiella pneumoniae
induced immunity when given to Swiss albino mice in 5-μg amounts and immune paralysis when given in 1,000-μg amounts. The unresponsive state lapsed to that of acquired immunity 3 months after induction. Passive transfer of cells from groups of
K. pneumoniae
immune, “paralyzed,” and control mice showed that peritoneal cells from “paralyzed” donors induced significant protection against challenge in both control and “paralyzed” recipients. In contrast, spleen cells from control, “paralyzed,” and immune animals failed to effect such transfer. The finding that unresponsiveness could be terminated by peritoneal cells and not spleen cells indicates that macrophages played a primary role in immune paralysis, possibly owing to their loss of capacity to transfer factors or information for induction of antibody synthesis.
Cytolytic Plasma Factor in Experimental Coccidioidomycosis
Authors: Landau Joseph W. , Newcomer Victor D.
Published: January 2020

Peripheral blood leukocytes from guinea pigs infected with
Coccidioides immitis
5 weeks previously were lysed significantly when incubated at 37 C for 3.5 hr with a concentrated
C. immitis
culture filtrate, but not with a concentrated
Aspergillus fumigatus
or
Blastomyces dermatitidis
culture filtrate. Mononuclear leukocytes and presumably granulocytes were both lysed. Characterization of the factor responsible for this leukocytolysis reaction revealed that it was contained in plasma and serum but not in leukocytes from infected guinea pigs. It was complement-dependent, active after heating at 56 C, and stable after storage at −20 C for as long as 14 months.
Experimental Infection of the Cotton Rat
Sigmodon hispidus
with
Rickettsia rickettsii
Authors: Shirai A. , Bozeman F. M. , Humphries J. W. , Elisberg B. L. , Faber J. E.
Published: January 2020

Studies of experimental infection of the cotton rat,
Sigmodon hispidus
, with the virulent Sheila Smith (R type) and the avirulent Si 7 (U type) strains of
Rickettsia rickettsii
were undertaken to evaluate the role of this native wild mammal in the ecology of Rocky Mountain spotted fever. The Sheila Smith strain, which was highly lethal for guinea pigs, was nonpathogenic for cotton rats. Serial passage of the R-type strain in the cotton rat did not alter the virulence of the agent for cotton rats or guinea pigs. The U-type strain, which was originally recovered from a wild cotton rat, could not be maintained beyond the first passage in this animal host. Rickettsemia in the cotton rat occurred over a 24-hr period after inoculation of the virulent strain but was detected only 1 hr after inoculation of the avirulent strain. The short period of rickettsemia suggests that the cotton rat probably is not an important reservoir of
R. rickettsii
. Specific complement-fixing antibodies developed rapidly after infection with either strain, but the antibodies evoked by the R strain attained higher titers and persisted longer. Cotton rats previously infected with the Sheila Smith strain developed rickettsemia after reinfection with the same strain, even though relatively high levels of antibody were still present.
Role of the Phagocyte in Host-Parasite Interactions XII. Hydrogen Peroxide-Myeloperoxidase Bactericidal System in the Phagocyte
Authors: McRipley R. J. , Sbarra A. J.
Published: January 2020

An antimicrobial system in polymorphonuclear neutrophils (PMN) consisting of myeloperoxidase and hydrogen peroxide has been proposed. This system appears to be activated during phagocytosis as a result of the stimulated metabolic activities. A lysed-granules (LG) fraction was prepared from guinea pig exudative PMN. LG alone possessed bactericidal activity which was related to the
p
H of the reaction; the lower the
p
H, the more marked the activity. When low concentrations of both H
2
O
2
and LG were combined under conditions where neither factor alone exhibited significant killing power, there was a striking increase in bactericidal activity. This enhanced activity was much greater than an additive effect. The LG-peroxide antibacterial system was most active over a
p
H range of 4.0 to 6.0. The activity of the LG-peroxide system was essentially abolished by peroxidase inhibitors, NaN
3
, KCN, and aminotriazole. The antibacterial activity of this system was nonspecific in nature, being equally effective against gram-negative and gram-positive organisms.
Avirulent
Clostridium perfringens
Strains Obtained by Euflavine Treatment
Authors: Paquette G. , Fredette V.
Published: January 2020

Clostridium perfringens
was incubated in the presence of euflavine (EU); the resistant mutants which were thus isolated had highly reduced capacity to release α-toxin. This fact was confirmed by lecithinase determinations and by immunoelectrophoresis. Injected into guinea pigs and into 6- to 7-day-old chicks, these mutants were completely avirulent. A study of their properties indicated biochemical differences between wild types and mutants.
Genetic and Biochemical Studies on Mannose-Negative Mutants That Are Deficient in Phosphomannose Isomerase in
Escherichia coli
K-12
Authors: Markovitz Alvin , Sydiskis Robert J. , Lieberman Michael M.
Published: January 2020

Two mannose-negative mutants of
Escherichia coli
K-12 have been isolated. These mutants are deficient in the ability to synthesize phosphomannose isomerase and capsular polysaccharide when grown on glucose-containing media. Interrupted mating experiments to determine the kinetics of genetic transfer show that the two mannose-negative mutations map together between the histidine and tryptophan regions of the
E. coli
chromosome.
Comparative Control of a Branch-Point Enzyme in Microorganisms
Authors: Jensen Roy A. , Nasser DeLill S. , Nester Eugene W.
Published: January 2020

Thirty-two genera of microorganisms were identified with one of six distinctive control patterns for the enzyme 3-deoxy-
d
-
arabino
-heptulosonate-7-phosphate synthetase. These patterns included sequential feedback inhibition, isoenzyme feedback inhibition, cumulative feedback inhibition, and three (apparent) simple one-effector patterns. Documentation is provided of an overwhelming tendency for control patterns to be strongly conserved among the member species of the various genera that were examined.
Role of a Cell-Wall Glucan-degrading Enzyme in Mating of
Schizophyllum commune
Authors: Wessels Joseph G. H. , Niederpruem Donald J.
Published: January 2020

Mycelial enzyme extracts of
Schizophyllum commune
were prepared during vegetative growth matings leading to common-
A
and common-
B
heterokaryons and the dikaryon, and were examined for hydrolytic activity against an alkaliinsoluble cell-wall glucan (R-glucan) isolated from this mushroom. In extracts from several individual homokaryotic mycelia the R-glucanase activity was low and did not increase when the cultures exhausted glucose in the medium. In common-
A
matings, a 30-fold increase in specific activity of intracellular R-glucanase was found even in the presence of glucose in the broth. An increase of this magnitude was not observed in the common-
B
mating nor in the fully compatible cross leading to the dikaryon. Extracts of the dikaryon did show elevated R-glucanase activity after exogenous glucose disappearance and subsequent fruiting. In none of these situations was an enzyme activity detected towards an alkali-soluble cell-wall glucan (S-glucan) prepared from
S. commune
. Changes in R-glucanase were not parallelled by identical changes in laminarinase, pustulanase, cellobiase, and
p
-nitrophenyl-β-
d
-glucosidase, but comparable increases in specific activities were found for hydrolysis of glycogen and maltose. After interaction of the various mycelia in mating combinations, the S-glucan/R-glucan ratio of the cell wall of the dikaryon was found to be similar to that of the homokaryons, but increased in the common-
B
interaction and was elevated almost threefold in the common-
A
heterokaryon.
Cytochrome Synthesis and Its Regulation in
Spirillum itersonii
Authors: Clark-Walker G. D. , Rittenberg B. , Lascelles J.
Published: January 2020

Spirillum itersonii
contains
b
- and
c
-type cytochromes as well as a carbon monoxide-binding pigment of the cytochrome
o
type. Synthesis of cytochromes
b
and
c
is increased by about two- and fourfold, respectively, when cells are transferred from high to low aeration. The increased concentration of cytochrome is not accompanied by an increase in the respiration rate of the cells. Both cytochrome
b
and cytochrome
c
are located in the particulate fraction of cells grown under high or low aeration, and both pigments are fully reducible by succinate. No evidence was found for the accumulation of the protein component of either cytochrome when synthesis of the prosthetic group was limited by iron deficiency, nor did heme or precursors accumulate when protein synthesis was prevented. It was therefore concluded that the formation of the heme prosthetic group is closely integrated with the synthesis of the protein moiety. δ-Aminolevulinate synthase was detected in extracts of the organism. Its activity was correlated with cytochrome synthesis; it was reduced by high aeration and increased under low aeration. The synthase was inhibited by hemin at concentrations of 10 μ
m
or higher. The observations are consistent with a central role for the heme prosthetic group in the regulation of cytochrome synthesis.
Induction of Excessive Deoxyribonucleic Acid Synthesis in
Escherichia coli
by Nalidixic Acid
Authors: Boyle James V. , Goss William A. , Cook Thomas M.
Published: January 2020

Prior treatment of
Escherichia coli
with nalidixic acid in nutritionally complete medium altered the subsequent pattern of deoxyribonucleic acid (DNA) synthesis normally observed in nutritionally deficient medium. Transfer of
E. coli
15 TAU to an amino acid- and pyrimidine-deficient medium usually resulted in a 40 to 50% increase in DNA content. Previous treatment with nalidixic acid caused a 200 to 300% increase in DNA content under these conditions. The extent of this DNA synthesis depended on the duration of prior exposure to nalidixic acid. The maximal rate of synthesis was obtained after a 40- to 60-min exposure to nalidixic acid and was two to three times that of the control. The
induction
of this excessive DNA synthesis was prevented by chloramphenicol or phenethyl alcohol, but the
synthesis
of this DNA was only partially sensitive to these agents. With
E. coli
TAU-bar, the rate of DNA synthesis, after removal of nalidixic acid, was similar to that of
E. coli
15 TAU, but the maximal amount of DNA synthesized was 180 to 185% of that initially present. Cesium chloride density gradient analysis demonstrated that DNA synthesis after removal of nalidixic acid occurs by a semiconservative mode of replication. The density distribution of this DNA was similar to that obtained after thymine starvation. These results suggest that nalidixic acid treatment may induce additional sites for DNA synthesis in
E.coli
.
Leukocytic Hypersensitivity in Experimental Group A Streptococcal Infections
Authors: Lau H. S. , Scherago M.
Published: January 2020

Skin hypersensitivity to streptococcal antigens was demonstrated in 15 New Zealand red rabbits that were sensitized by intracutaneous injections with group A streptococci, and leukocytic hypersensitivity, as determined by in vitro inhibition of leukocyte migration, was demonstrated in 11 of the rabbits. The skin hypersensitivity persisted for at least 8 weeks, whereas the leukocytic hypersensitivity generally waned rather rapidly. The leukocytic hypersensitivity reappeared in the infected rabbits that had developed this hypersensitivity. However, it did not reappear on reimmunization with living streptococci of the type originally employed, whereas it did reappear with living but not heat-killed streptococci of another M type.
Presence of Rhapidosomes in Various Species of Bacteria and Their Morphological Characteristics
Authors: Yamamoto T.
Published: January 2020

Rod-shaped structures have been observed in cells of
Pseudomonas, Photobacterium, Proteus
, and
Saprospira
by use of the negative-contrast stain. These structures, referred to as rhapidosomes, appear to be normal components of these cells. Other bacteria including
Escherichia, Salmonella, Shigella, Klebsiella, Micrococcus, Bacillus, Mycobacterium, Rhodospirillum
, and
Hydrogenomonas
genera failed to reveal these structures. The rhapidosomes of
Saprospira
were found to consist of two rods, one encasing a narrower, longer structure. In contrast, the rhapidosomes of
Pseudomonas, Proteus
, and
Photobacterium
were without the rigid inner structure, but were occasionally seen filled with a homogeneous material as observed by the negative stain. Ultrathin sections of
Pseudomonas
cells indicate that these rhapidosomes are embedded within or are in close association with the nucleoplasm.
Mode of Action of Myxin on
Escherichia coli
Authors: Lesley S. M. , Behki R. M.
Published: January 2020

The effect of the new antibiotic, myxin, on the syntheses of deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein in
Escherichia coli
(strains B and 15T
−
) was examined. Within 7 min of the addition of myxin at 5 μg/ml, the synthesis of new bacterial DNA was almost completely inhibited. This was followed by an extensive degradation of the pre-existing DNA to an acid-soluble form. All of the evidence indicated that the primary effect of the antibiotic was on cellular DNA. The synthesis of RNA was completely inhibited after 15 min of exposure to myxin (5 μg/ml), and the synthesis of protein was markedly reduced after 30 min. There was no measurable breakdown of either RNA or protein in the myxin-treated cells. A marked stimulation of
14
C-uracil incorporation was found in the presence of myxin in 15T
−
cells only. This did not result from an increased rate of RNA synthesis but was due to an increase in the proportion of exogenous uracil, relative to endogenous uracil, incorporated into cellular RNA. This probably reflected a partial inhibition of the biosynthesis of uridine monophosphate from orotate. At 4.5 μg of myxin per ml and with 0.8 × 10
8
cells per ml, 50% of the antibiotic was reduced in 15 min from the biologically active oxidized form to the biologically inactive state. Under these conditions, a maximum of 0.6% (27 μμg/ml) of the myxin was retained in the cells.
Biosynthesis of Biotin in Microorganisms V. Control of Vitamer Production
Authors: Birnbaum Jerome , Pai Chik H. , Lichstein Herman C.
Published: January 2020

Use of a yeast-lactobacillus differential microbiological assay permitted investigation into the synthesis of biotin vitamers by a variety of bacteria. A major portion of the biotin activity was found extracellularly. The level of total biotin (assayable with yeast) greatly exceeded the level of true biotin (assayed with lactobacillus). Values for intracellular biotin generally showed good agreement between the assays, suggesting the presence of only true biotin within the cells. Bioautographic analysis of the medium after growth of each organism revealed the presence of large amounts of a vitamer which corresponded to
dl
-desthiobiotin on the basis of

R
f

value and biological activity. Biotin, when detected at all, was at very low concentrations. Also, an avidin-uncombinable vitamer was synthesized by a majority of the bacteria. Addition of
d
-biotin to the growth medium prevented completely the synthesis of both vitamers of biotin.
d
-Biotin-
d
-sulfoxide had no effect on the synthesis of desthiobiotin or the avidin-uncombinable vitamer. Addition of
dl
-desthiobiotin did not prevent its own synthesis nor that of the other vitamer. Control of vitamer synthesis is therefore highly specific for
d
-biotin. The avidin-uncombinable vitamer was produced only at repressed levels in the presence of high concentrations of both
d
-biotin and
dl
-desthiobiotin, which suggested that it is not a degradation product of these substances. A possible mechanism for the overproduction of the biosynthetic precursors of biotin is presented.
Extraction, Characterization, and Cellular Localization of the Lipids of
Staphylococcus aureus
Authors: White David C. , Frerman Frank E.
Published: January 2020

Satisfactory extraction and assay procedures have been developed for the lipids of
Staphylococcus aureus
. The following lipids have been characterized in detail: the vitamin K
2
, which is shown to exist as isoprenologues with side chains of 35, 40, and 45 carbon atoms; monoglucosyldiglyceride and diglucosyldiglyceride, which account for all the carbohydrate in the lipid extracts; the lysyl ester of phosphatidyl glycerol, phosphatidyl glycerol, and cardiolipin, which account for 98% of the phosphate in the lipid extract. The extraction procedure removes 98% of the total bacterial fatty acids. Acidification of the medium before harvest and refluxing in isopropanol are critical in the extraction procedure for the maximal recovery of lysyl-phosphatidyl glycerol and the glucolipids. The lipids have been shown to be a part of the same membrane as the respiratory pigments.
Tracer Studies to Locate the Site of Platinum Ions Within Filamentous and Inhibited Cells of
Escherichia coli
Authors: Renshaw E. , Thomson A. J.
Published: January 2020

The distribution of platinum ions within
Escherichia coli
after the induction of filaments with
cis
-Pt(NH
3
)
2
Cl
4
, and after growth inhibition by PtCl
6
2−
, has been determined with radioactive metal compounds (
191
Pt, with a half-life of approximately 3 days) by the simple chemical procedure of Roberts et al. In the filamentous cells, the platinum metal is associated with metabolic intermediates, nucleic acids, and cytoplasmic proteins; whereas, in inhibited cells, the platinum is combined only with the cytoplasmic protein. Similar experiments with gram-positive cells of
Bacillus cereus
and
Staphyloccus aureus
, which show no filamentous growth in the presence of
cis
-Pt(NH
3
)
2
Cl
4
, reveal that the metal complex does penetrate the cell wall and subsequently becomes bound predominantly by metabolic intermediates.
Control of Malate Synthase Formation in
Rhizopus nigricans
Authors: Wegener Warner S. , Schell Jane E. , Romano Antonio H.
Published: January 2020

The control of malate synthase formation in a fumaric acid-producing strain of
Rhizopus nigricans
has been found to be similar in most respects to that of isocitrate lyase, the companion enzyme of the glyoxylate bypass. A basal level is formed in a casein hydrolysate medium, which is repressed by glucose. Utilization of glucose during growth results in relief of glucose repression. Any factor which stimulates growth promotes relief of glucose repression by enhancing the incorporation of repressor metabolites derived from glucose into cell material. Thus, malate synthase formation was enhanced in glucose-containing media by the addition of zinc, or by an increase of the concentration of available nitrogen source in a synthetic medium. Both acetate and glycolate acted as apparent inducers of malate synthase, with glycolate the more effective of the two when added alone. Acetate induction was enhanced by Zn
++
, however, whereas induction by glycolate was unaffected. This supports the concept that acetate stimulates formation of glyoxylate bypass enzymes by a derepression mechanism, whereas glycolate or a product derived from it acts directly as an inducer. Moreover, it is indicated that the malate synthases induced by acetate and glycolate are separate and distinct, as has been shown in
Escherichia coli
.
Cold-Sensitive Mutation of
Pseudomonas putida
Affecting Enzyme Synthesis at Low Temperature
Authors: Condon Séamus , Ingraham John L.
Published: January 2020

A cold-sensitive mutant of
Pseudomonas putida
has been isolated which grows normally at 30 C but is unable to grow on mandelate as a source of carbon at 15 C. The mutation results in the inability of the strain to carry out the reaction catalyzed by
cis,cis
-muconate lactonizing enzyme at low temperature and must lie in the structural gene for that enzyme, because the mutant enzyme produced at 30 C shows altered thermal stability. The mutant enzyme is not intrinsically cold-labile, nor is it cold-labile at the moment of synthesis. The activity of the mutant enzyme is not inhibited at low temperature. Evidence is presented to establish that this mutation in the structural gene coding for
cis,cis
-muconate lactonizing enzyme results in the lack of expression of that gene at low temperature.
Transient Repression of the
lac
Operon
Authors: Tyler Bonnie , Loomis William F. , Magasanik Boris
Published: January 2020

Severe transient repression of constitutive or induced β-galactosidase synthesis occurs upon the addition of glucose to cells of
Escherichia coli
growing on glycerol, succinic acid, or lactic acid. Only mutants particularily well adapted to growth on glucose exhibit this phenomenon when transferred to a glucose-containing medium. No change in ribonucleic acid (RNA) metabolism was observed during transient repression. We could show that transient repression is pleiotropic, affecting all products of the
lac
operon. It occurs in a mutant insensitive to catabolite repression. It is established much more rapidly than catabolite repression, and is elicited by glucose analogues that are phosphorylated but not further catabolized by the cell. Thus, transient repression is not a consequence of the exclusion of inducer from the cell, does not require catabolism of the added compound, and does not involve a gross change in RNA metabolism. We conclude that transient repression is distinct from catabolite repression.
Serological Studies of Ungroupable
Neisseria meningitidis
Authors: Hollis Dannie G. , Wiggins Geraline L. , Schubert Joseph H.
Published: January 2020

Verification that Slaterus'
Neisseria meningitidis
serotypes X, Y, and Z are groups distinct from each other and from groups A, B, C, and D was made by use of the tube agglutination test on absorbed and unabsorbed antisera. A significant number of meningococcal strains in this country, which could not be classified serologically with standard antisera prepared to Branham's neotype A, B, C, and D strains, were grouped specifically with antisera prepared to the Slaterus types. The strains grouped as X, Y, and Z were from various geographical areas of the United States and were isolated from both carriers and cases. Over a 2-year period, the cultures tested ranged in predominance in descending order as follows: group B, C, Y, X, Z, A, and D. It is recommended that Slaterus' types should be considered as standard groups and follow in alphabetical order with the standard A, B, C, and D groups; i.e., X would be designated as group E, Y as group F, and Z as group G. It was observed that false-grouping cross-reactions could be greatly reduced by reconstituting the lyophilized grouping antisera in 50% glycerol-water. Of 99 cultures which could not be specifically grouped with antisera reconstituted in distilled water, 19 were specifically grouped with antisera reconstituted in 50% glycerol-water.
Intracellular Synthesis of
Clostridium botulinum
Type B Toxin I. Demonstration of Toxin Synthesis and Sedimentation Studies on Toxic Products
Authors: Gerwing Julia , Morrell Robert W. , Nitz Rodney M.
Published: January 2020

The synthesis and nature of the toxin of
Clostridium botulinum
type B were studied in growing cells. It was demonstrated that the toxin was synthesized in the latter stage of logarithmic growth and was released into the culture supernatant fluid during lysis of the cells. Studies were done on the sedimentation properties of intracellular toxin. Two components were demonstrated, one of low molecular weight and low specific activity and one of high molecular weight with specific activity similar to that isolated from culture lysates. The high molecular weight toxin was shown to be composed of an aggregate of small subunits, separable with either high ionic strength or sodium dodecyl sulfate.
Use of Radioactive Antibodies for Characterizing Antigens and Application to the Study of Flagella Synthesis
Authors: Grant Geoffrey F. , Simon Melvin
Published: January 2020

A simple rapid immunochemical procedure has been developed which provides information about the qualitative and quantitative nature of antigens. It involves the use of purified radioactive (125I-labeled) antibodies. The amount of antibody bound to the antigen is determined by filtering the mixture through diethylaminoethyl (DEAE)-cellulose paper. All of the antigen, as well as the antibody complexed with it, is trapped on the paper, whereas free antibody is removed by repeated washing. This technique has been applied to the study of three immune systems, bovine serum albumin,Escherichia colitryptophan synthetase B protein, andBacillus subtilisflagella. The results obtained by the DEAE-antibody binding technique were comparable, in terms of sensitivity, specificity, and accuracy, to data obtained by microcomplement fixation and precipitin methods. The assay was used to measure the kinetics of flagella regeneration inB. subtilis.
Evidence for Two Species of Glutamate Dehydrogenases in
Thiobacillus novellus
Authors: LéJohn H. B. , McCrea Barbara-Ellen
Published: January 2020

When grown autotrophically in a thiosulfate-mineral salts medium, cells of the facultative chemoautotrophic bacterium,
Thiobacillus novellus
, produced two distinct glutamate dehydrogenases, one specific for nicotinamide adenine dinucleotide phosphate (NADP) and the other specific for nicotinamide adenine dinucleotide (NAD). When glutamate was supplied exogenously as the sole carbon source, the NAD-specific glutamate dehydrogenase was fully induced. Lower levels of the enzyme were found in bacteria grown in
l
-arginine,
l
-alanine, glucose, glycerol, lactate, citrate, or succinate. Arginine, histidine, and aspartate, on the other hand, caused a marked repression of the NADP-specific glutamate dehydrogenase activity. The NAD-dependent glutamate dehydrogenase was allosteric. Adenosine-5′-monophosphate and adenosine-5′-diphosphate acted as positive effectors. Both glutamate dehydrogenases were purified about 250-fold and were shown to be distinct protein with different physical properties.