bluuebunny/crossref_metadata_2025 huggingface dataset:
Membrane Lipid Changes During Formation of a Functional Electron Transport System in
Staphylococcus aureus
Authors: Frerman Frank E. , White David C.
Published: January 2020

Addition of oxygen to a culture of anaerobically growing
Staphylococcus aureus
results in the formation of a membrane-bound, functional electron transport system. With the shift to aerobic growth, there is at least a 15-fold increase in cytochrome
a
and at least a 55-fold increase in cytochrome oxidase
o
. At the completion of the shift to aerobic growth, the cytochrome levels equal those found in bacteria grown with aeration throughout the entire growth cycle. Cytochromes
b
1
and
o
are formed first. Their synthesis slows when cytochrome
a
becomes detectable. Concentrations of cytochromes
b
1
and sometimes cytochrome
a
increase late in the adaptive period. Concomitant with this is a decrease in the oxygen tension at which the rate of oxygen utilization becomes dependent on the oxygen concentration. During the shift to aerobic growth, the protoheme content increases ninefold, and all the protoheme can be accounted for in enzymatically reducible cytochrome
b
1
and cytochrome oxidase
o
. Protoheme, but not a functional cytochrome system, is synthesized by anaerobically growing
S. aureus
. Heme
a
appears only after a period of aerobic growth. During the shift to aerobic growth, there is a 1.6-fold increase in the vitamin K
2
content, with an alteration in the ratios of the 35 and 45 carbon side chain isoprenologues. A twofold increase in phosphatidyl glycerol and a 1.6-fold increase in cardiolipin occur with the shift to aerobic growth. Lysyl-phosphtidyl glycerol remains essentially constant in this period. Concentrations of mono- and diglucosyl diglycerides increase coordinately 1.3-fold during the shift to aerobic growth at a 2.5 to 1
m
ratio.
O-Methylthreonine Inhibition of Growth and of Threonine Deaminase in Escherichia coli
Authors: Smulson Mark E. , Rabinovitz Marco , Breitman T. R.
Published: January 2020

O
-methylthreonine (OMT), an isosteric analogue of isoleucine, markedly inhibited growth of
Escherichia coli
15. This inhibition was overcome most effectively by addition of isoleucine, valine, or leucine to the medium and less effectively by addition of threonine. The dipeptide, valylleucine, also relieved the OMT-induced inhibition but only after a lag period, suggesting that valine and leucine, liberated by dipeptidase action, compete with OMT for entry into the cell. OMT was activated and transferred to transfer ribonucleic acid (RNA) by isoleucyl-RNA synthetase in vitro. The rate of OMT incorporation into protein of intact cells was comparable to that of isoleucine. In contrast to isoleucine, very high concentrations of OMT were required to inhibit threonine deaminase, and the inhibition was strictly competitive with threonine. In addition, OMT inhibited a threonine deaminase preparation desensitized to isoleucine inhibition.
Effect of Substrate on the Fatty Acid Composition of Hydrocarbon-utilizing Microorganisms
Authors: Dunlap K. R. , Perry J. J.
Published: January 2020

The fatty acid pattern in three hydrocarbon-utilizing bacteria during growth on various substrates was examined. The predominant fatty acids in acetate-grown cells were C16, C16:1, C18:1, and Br—C19and the major fatty acids in propane-grown cells were C15, C17, C17:1, C18:1, and Br—C18. When one organism (Mycobacteriumsp. strain OFS) was grown on then-alkanes from C13to C17, the major fatty acid in the cells was of the same chain length as the substrate. Studies on the incorporation of acetate into the cellular fatty acids of microorganisms growing on C15and C17n-alkanes suggest that the oxidative products of the substrate are incorporated into the cellular fatty acids without degradation to acetate.
Effect of Nutrients on Physiological Properties of
Clostridium botulinum
Type E
Authors: Gullmar B. , Molin N.
Published: January 2020

Eight strains of
Clostridium botulinum
type E out of twelve tested showed good growth and normal cell morphology in a synthetic medium containing choline. Growth and toxin production by a representative strain was not influenced by repeated subculturing. In the chemically defined medium, acetylcholine,
N,N
-dimethylethanolamine, and lecithin could replace choline to get normal cell division and cell morphology of
C. botulinum
type E. Choline could not be replaced by ethanolamine,
N
-methylethanolamine, or betaine. A toxigenic strain of
C. botulinum
type E showed proteolytic, lipolytic, and lecithinase activity in complex media but not in a synthetic medium. On prolonged incubation in the high temperature range of growth, the toxicity of the culture filtrate decreased in a complex, but not in a synthetic medium. The implications of these findings are discussed.
Biosynthesis of Biotin in Microorganisms VI. Further Evidence for Desthiobiotin as a Precursor in
Escherichia coli
Authors: Pai Chik H. , Lichstein Herman C.
Published: January 2020

Biotin auxotrophs were isolated from
Escherichia coli
K-12. One of the mutants was unable to grow on desthiobiotin and accumulated a large amount of a vitamer in medium when growing on an optimal concentration of biotin. The production of the vitamer was inhibited in the presence of an excess amount of biotin. The vitamer was identified as desthiobiotin on the basis of biological activities, avidin combinability, and chromatographic characteristics. The mutant lacked the ability to convert desthiobiotin to biotin. These results further support the hypothesis that desthiobiotin is a normal intermediate in the biosynthesis of biotin in
E. coli
.
Dominance Studies with Stable Merodiploids in the
d
-Serine Deaminase System of
Escherichia coli
K-12
Authors: McFall Elizabeth
Published: January 2020

An episome, F32, which carries the genetic markers
dsdA
+
, the presumed structural gene for
d
-serine deaminase,
dsdC
+
, a regulatory locus governing the synthesis of
d
-serine deaminase,
aroC
+
, and
purC
+
was obtained from strain AB311 of
Escherichia coli
K-12, and was used to construct appropriate merodiploids with
dsdC
markers. In all
dsdC
/
dsdC
+
diploids examined,
dsdC
was found to be
cis
dominant,
trans
recessive, to
dsdC
+
. In two cases, however, the
cis
dominance was only partial. Moreover, complementation was observed between one of the
dsdC
markers which is fully
cis
dominant and one which is partially
cis
dominant. Because of the size of the
dsdC
region, the phenotypes of the mutants, and the partial
trans
dominance of
dsdC
+
over some of the
dsdC
mutations, it is suggested that the
dsdC
region specifies a product, but that this product does not move with facility through the cytoplasm
“Position Effect” on Dominance in the
d
-Serine Deaminase System of
Escherichia coli
K-12
Authors: McFall Elizabeth
Published: January 2020

A completely stable F32 merodiploid has been isolated, which has the
dsd
genotype
dsdA
+
dsdCx3
/F
-dsdA
+
dsdC
+
. The stabilization apparently does not result from an alteration in the F, or from its integration in the chromosome, but rather from a chromosomal aberration. The stable strain can exist in two forms, which interconvert at low frequency. In one form, the episomal
dsd
markers are in normal apposition with the chromosomal markers, and in this case
cis
dominance of
dsdCx3
is incomplete. In the other form, the two regions are not in normal apposition, and
dsdCx3
is completely
cis
dominant. A model to explain these findings is presented.
Characterization of Deoxyribonucleic Acids from Streptomycetes and Nocardiae
Authors: Tewfik Enayat M. , Bradley S. G.
Published: January 2020

The relationships among selected streptomycetes, nocardiae, and mycobacteria have been determined, based upon the base composition of their deoxyribonucleic acid (DNA) and upon the ability of their denatured DNA to anneal with single-stranded reference DNA. The streptomycetes constituted a homogeneous group whose DNA contained between 69 and 73 mole% guanine + cytosine (% GC). Moreover, the streptomycetes examined showed 37 to 88% homology with the
Streptomyces venezuelae
and
S. rimosus
reference DNA. The nocardial and mycobacterial DNA both contained 62 to 69% GC. The nocardial strains studied fell into either a 62 to 64% GC group or a 68 to 69% GC group, indicating that they should not be assigned to a single species. The nocardiae having 68 to 69% GC showed 24 to 44% homology with
S. venezuelae
reference DNA. In competition experiments, wherein unlabeled heterologous DNA interfered with binding of labeled homologous DNA, the nocardial DNA with 68 to 69% GC showed a greater degree of homology with the streptomycetes than did the nocardial DNA with 62 to 64% GC. In addition, the DNA from spores of
S. venezuelae
was cursorily examined, and interactions between
S. venezuelae
denatured DNA and polyribonucleotides were sought. The buoyant density of the DNA from
S. venezuelae
spores was distinctly less than that from mycelia. Moreover, denatured
S. venezuelae
DNA formed a dense complex with polyriboguanylate.
Enzymes of the Tryptophan Synthetic Pathway in
Pseudomonas putida
Authors: Enatsu Toshio , Crawford Irving P.
Published: January 2020

The first four enzymatic activities of the tryptophan synthetic pathway in
Pseudomonas putida
were found on separate molecules. Gel filtration and density gradient centrifugation experiments did not disclose any associations or aggregations among them. These findings contrast with the situation found in the enteric bacteria, where the first two activities are found in an aggregate and the third and fourth are catalyzed by a single enzyme. Tryptophan synthetase, the last enzyme of the pathway, consists of two dissociable components. The affinity of these components is less in
P. putida
than is the case in
Escherichia coli
.
Ion Metabolism in a Potassium Accumulation Mutant of
Escherichia coli
B I. Potassium Metabolism
Authors: Damadian Raymond
Published: January 2020

A potassium transport mutant of
Escherichia coli
is described which is deficient in the intake of potassium. The phenotype of this mutant is characterized by (i) failure to grow in K
+
-deficient medium, (ii) failure to accumulate K
+
in K
+
-deficient medium, (iii) a steady-state intracellular K
+
that varies sigmoidally with the medium K
+
concentration, (iv) a signoidally shaped rate-concentration curve and a curved reciprocal plot for net K
+
uptake kinetics, and (v) a low steady-state flux of potassium associated with a reduced influx rate constant. The data are discussed in terms of the present day models of cation transport. These models have led to four possible explanations of the mutant's phenotype: (i) a selectivity reversal such that intracellular cation binding sites bind another cation instead of K
+
; (ii) a structural alteration of cation binding cell proteins so that K
+
is bound by “cooperative binding” (sigmoid isotherm) instead of by simple adsorption (hyperbolic isotherm); (iii) conversion of an enzyme in intermediate metabolism that rate-limits K
+
uptake to an allosteric protein; (iv) conversion of the “carrier protein” for K
+
to an allosteric protein.
Evidence for a Relationship Between Deoxyribonucleic Acid Metabolism and Septum Formation in
Escherichia coli
Authors: Walker James R. , Pardee Arthur B.
Published: January 2020

Septum formation is a key step in bacterial division, but the mechanism which controls periodic septum formation is unknown. In an attempt to understand this mechanism,
lon
−
mutants, in which septum formation is blocked by very doses of ultraviolet light (UV), were investigated. UV must act on some part of the apparatus of cytokinesis; thus, identification of the UV target would identify part of this apparatus. As likely possibilities, UV might damage the septum-forming site or it might damage deoxyribonucleic acid (DNA), since DNA replication is normally coordinated with septum formation. To distinguish between these possibilities, DNA was specifically sensitized by incorporating bromodeoxyuridine into
lon
−
bacteria. These bacteria were strongly sensitized to longer wavelength UV (2,900 to 3,100 A) so that they failed to form septa, grew into filaments which lysed, and did not form colonies. Various control experiments supported the conclusion that UV inhibits septum formation as a result of alterations in DNA metabolism. A relationship thus exists between DNA metabolism and septum formation.
Transformability of Streptomycin-resistant Group H Streptococci
Authors: Perry Dennis
Published: January 2020

Several resistant mutants of a transformable group H streptococcus, strain Challis, were isolated from media containing high concentrations of streptomycin. Mutants SR5a and SR5 exhibited high and low transformability, respectively, when exposed to deoxyribonucleic acid (DNA) from a novobiocin-resistant Challis strain. With similar exposure, mutant SR30 exhibited loss of transformability. The mutants further differed from the parent strain in time of appearance of optimal competence, and, in the case of SR5 and SR30, total growth was somewhat less than that of the parent. The rapidity with which transformants appeared upon initial exposure to DNA was approximately the same in the mutants and the parent strain. The decrease or loss of transformability of mutants SR5 and SR30 was found to be due to an alteration in capacity to take up DNA. Mutant SR5a (highly transformable) was further differentiated from mutants SR5 and SR30 in that it was somewhat more sensitive to high concentrations of streptomycin. Transformants obtained by treating strain Challis with the three types of mutant DNA, on the other hand, exhibited similar degrees of resistance to increasing concentrations of streptomycin. The additional decrease in transforming ability of mutant SR5a and the loss of transforming ability of mutant SR5 after a second exposure to streptomycin may indicate a stepwise process in the change from transformability to nontransformability. Although streptomycin resistance may not be directly related to inability to transform, results indicate that streptomycin greatly increases the chances of selecting these mutants and also can be of value in serving as a marker in studies of this nature.
Host-Parasite Relationships Among Group A Streptococci IV. Suppression of Antibody Response by Streptococcal Pyrogenic Exotoxin
Authors: Hanna Edgar E. , Watson Dennis W.
Published: January 2020

In rabbits, purified streptococcal pyrogenic exotoxin, at 0.002 of the
ld
50
dose, suppressed the antibody response to injected sheep erythrocytes. The antibody suppressed was determined by density gradient ultracentrifugal analysis to be of the 19
S
class. Background serum antibody (50% hemolytic units), as determined photometrically, correlated well with background antibody-forming spleen cells, as determined by the hemolytic-plaque technique. The exotoxin induced neither positive nor negative changes in background antibody levels, but suppressed the early secondary response to injected antigen. A comparison and control experiment showed that purified gram-negative bacterial endotoxin at identical protocol did not induce antibody suppression, but did induce the well-known adjuvant effect. Because streptococcal pyrogenic exotoxin is known to inhibit the phagocytic function of the reticuloendothelial system (RES), these data strongly support the concept that antigen is processed by cells of the RES before it evokes a secondary immune response. The results also demonstrated that streptococcal pyrogenic exotoxin may play a unique role in lowering the acquired defense of the host against infection. If the anamnestic immune response of the host is temporarily suppressed, then the host-parasite balance would be upset in favor of the parasite.
Taxonomy of
Azotomonas
Species
Authors: Parejko R. A. , Wilson P. W.
Published: January 2020

The ability of two strains of
Azotomonas insolita
and one strain classified only as
Azotomonas
species to use molecular nitrogen was investigated by use of several techniques. Molecular
15
N
2
incorporation by growing cultures of
Azotomonas
was inconsistent and limited. In addition, attempts to demonstrate nitrogen fixation in growing cultures by the radioactive
13
N
2
technique were negative. Experiments were done in which the total nitrogen content of a culture was determined by a micro-Kjeldahl method. None of these experiments resulted in a significant increase in total nitrogen. Attempts to show a diauxie effect, that is, transition from growth on NH
4
+
to N
2
, were also unsuccessful. Nitrogen fixation by cell-free extracts of
A. insolita
was negative, as determined by reduction of N
2
to NH
3
, and reduction of cyanide, of acetylene, and of azide. These negative results suggest that the taxonomic reclassification of the genus
Azotomonas
should be considered.
Regulation of
Staphylococcus aureus
Lactate Dehydrogenase
Authors: Garrard W. , Lascelles J.
Published: January 2020

The effect of growth conditions on the specific activity of nicotinamide adenine dinucleotide (NAD)-linked lactate dehydrogenase (LDH) in extracts of
Staphylococcus aureus
strain SG 511A was examined. Kinetic and electrophoretic experiments, with extracts prepared from aerobically and anaerobically grown cells, provided evidence for only one physiologically significant enzyme. The aerobic level of NAD-linked LDH of
S. aureus
remained constant and was independent of the carbon source. In contrast, the level of LDH produced in an anaerobic environment was variable and was dependent on the carbon source. Growth anaerobically on pyruvate, as the sole fermentable carbon source, resulted in a maximal level of LDH activity, a value about eightfold greater than the aerobic level. Anaerobic growth either on pyruvate plus glucose or on glucose alone, however, resulted in approximately a threefold decrease in this maximum. Experiments with a heme-requiring auxotroph derived from
S. aureus
demonstrated that the aerobic level of LDH activity was dependent on a functional respiratory chain.
Activation of Fatty Acid Synthesis in Cell-free Extracts of
Saccharomyces cerevisiae
Authors: Rasmussen Roberta K. , Klein Harold P.
Published: January 2020

Fatty acid synthesis from acetate in extracts of
Saccharomyces cerevisiae
strain LK2G12 was shown to be stimulated by α-glycerophosphate and citrate, and by a number of compounds related to them. Magnesium was shown to stimulate fatty acid synthesis from acetyl-coenzyme A but not from malonyl-coenzyme A, thus indicating the site of stimulation of fatty acid synthesis to be the acetyl-coenzyme A step.
Proteinase Enzyme System of Lactic Streptococci III. Substrate Specificity ofStreptococcus lactisIntracellular Proteinase
Authors: Cowman R. A. , Yoshimura S. , Swaisgood H. E.
Published: January 2020

The substrate specificity of an intracellular proteinase fromStreptococcus lactiswas investigated in an effort to understand the role of the enzyme in the cell. Peptides in which the N-terminal residue was glycine were not hydrolyzed by the enzyme (exceptions were glycyl-alanine, glycyl-aspartic acid, and glycyl-asparagine), but the peptide was hydrolyzed if the N-terminal residue was alanine. The enzyme also showed activity toward peptides containing aspartic acid or asparagine. Hydrolysis of only the peptide bonds of alanyl, aspartyl, or asparaginyl residues was confirmed by the action of the enzyme on oxidized bovine ribonuclease A- and B- chain insulin. The N-terminal residues of the peptide fragments liberated were identified. The enzyme attacked both substrates only at alanyl, aspartyl, and asparaginyl residues, releasing these as free amino acids. In addition to alanine, aspartic acid, and asparagine, certain other amino acids were liberated from ribonuclease A, but these were accounted for by the relation of their position to alanine, aspartic acid, and asparagine residues.
Isolation and Chemical Structure of the Peptidoglycan of
Spirillum serpens
Cell Walls
Authors: Kolenbrander P. E. , Ensign J. C.
Published: January 2020

The peptidoglycan layer of
Spirillum serpens
cell walls was isolated from intact cells after treatment with sodium dodecylsulfate and digestion with Pronase. The isolated peptidoglycan contained glucosamine, muramic acid, alanine, glutamic acid, and
meso
-diaminopimelic acid in the approximate molar ratio of 1:1:2:1:1. Aspartic acid and glycine were the only other amino acids found in significant quantities. N-terminal amino acid analyses of the tetrapeptide amino acids in the peptidoglycan revealed that 54% of the diaminopimelic acid molecules are involved in cross-linkage between tetrapeptides. This amount of cross-linkage is greater than that found in the peptidoglycan of previously studied cell walls of gram-negative bacteria. The polysaccharide backbone was isolated, after myxobacter AL-1 enzyme digestion of the peptidoglycan, by fractionation with ECTEOLA-cellulose and Sephadex G-100. An average length of 99 hexosamines for the polysaccharide chains was found (ratio of total hexosamines to reducing end groups).
Properties of Bacteria Isolated from Deep-Sea Sediments
Authors: Quigley M. M. , Colwell R. R.
Published: January 2020

Thirty-eight isolates were subjected to taxonomic analysis by computer. Of the 38 isolates, 31 were from sediment samples collected at depths from 9,400 to 10,400 meters in the Philippine and Marianas Trenches of the Pacific Ocean, and 7 cultures were from seawater samples collected at various depths from surface to 4,000 meters and from several locations in the Pacific Ocean. A total of 116 characteristics were determined for each isolate, coded, and transferred to punch cards. Similarity values were obtained by computer analysis, with the use of two recently developed computer programs. Five distinct phenetic clusters were observed from the numerical analyses. Four of the clusters were identified as species of the genusPseudomonas, and one, as an aerogenic species ofAeromonas. Group IV was identified as pigmentedPseudomonas fluorescens, and the major cluster, consisting of groups I and II, which merged at a species level of similarity, was treated as a new species ofPseudomonas. The 38 strain data were compared with data for 132 marine and nonmarine strains previously subjected to computer taxonomic analysis. The barotolerant deep-sea strains, with the exception of the deep-seaP. fluorescensisolates, clustered separately from all other marine strains.
Further Electron Microscope Characterization of Spore Appendages of
Clostridium bifermentans
Authors: Yolton Diane P. , Pope Leodocia , Williams M. Glenn , Rode L. J.
Published: January 2020

Two distinct spore appendage types of
Clostridium bifermentans
, a pinlike appendage and a tubular appendage, were studied by electron microscopy. The pinlike appendage is characterized by a shaft, about 100 A in diameter, which has a lobed caplike structure. The tubular appendage, 500 to 600 A in diameter, is characterized by a hirsute region consisting of small filaments or fibrils. Gross morphology and ultrastructural features of both types are described.
Characterization of Chloramphenicol Acetyltransferase from Chloramphenicol-resistant
Staphylococcus aureus
Authors: Shaw W. V. , Brodsky R. F.
Published: January 2020

Chloramphenicol-resistant strains of
Staphylococcus aureus
contain an inducible enzyme which inactivates chloramphenicol by acetylation in the presence of acetyl coenzyme A. The products of acetylation are chromatographically indistinguishable from those obtained with chloramphenicol-resistant
Escherichia coli
harboring an R factor. The kinetics of induction of chloramphenicol acetyltransferase are complicated by the inducer's effect on protein biosynthesis and its fate as chloramphenicol 3-acetate, which is not an inducer of the enzyme. The
E. coli
and
S. aureus
enzymes have been compared, with the conclusion that they are identical with respect to molecular weight (approximately 78,000) and
p
H optimum (7.8), but differ with respect to heat stability, substrate affinity, electrophoretic mobility, and immunological reactivity. Antiserum prepared against enzyme from
E. coli
contains precipitating antibody, which inactivates the
E. coli
enzyme, but neither precipitates nor neutralizes the activity of
S. aureus
enzyme.
Extracellular Collagenase from
Trichophyton schoenleinii
Authors: Rippon John W.
Published: January 2020

The dermatophyte
Trichophyton schoenleinii
elaborates an extracellular collagenase which is specific for native collagen and gelatin and is separable from an enzyme which is active against Azocoll. The fungal enzyme differs from the bacterial collagenases in its acid
p
H and small molecular weight. In addition, the fungal enzyme is irreversibly inhibited by ethylenediaminetetraacetic acid, whereas the bacterial enzymes can be restored by divalent cations, such as Mg
++
and Ca
++
.
Galactosidase Activity of Lactose-positive
Neisseria
Authors: Corbett William P. , Catlin B. Wesley
Published: January 2020

The chromogenic substrate
o
-nitrophenyl-β-
d
-galactopyranoside (ONPG) was hydrolyzed by lactose-positive
Neisseria
. Eight strains of pharyngeal origin were examined. In culture reactions, seven strains resembled
Neisseria meningitidis
with the exception that they produced acid from 1% (w/v) lactose. An eighth strain (V8) differed in that it did not form acid from maltose or from 1% lactose. However, acid formation was observed in 10% lactose cultures of strain V8, suggesting that entry of lactose occurred by passive diffusion, rather than as a result of permease activity. The enzymes which hydrolyzed ONPG were produced constitutively by the cells of all eight strains. Thus, specific activity in these strains was not increased by prior exposure to lactose, or to two other possible inducers, isopropyl-β-
d
-thiogalactoside or methyl-β-
d
-thiogalactoside. Study of cell-free extracts of one strain showed that the enzyme was heat-labile, having a half-life of 10 min at 45 C. The enzyme was unstable at low protein concentrations, but it was protected completely or partially when albumin or manganous ions were added. The enzyme appeared to be a typical β-galactosidase: α-galactosides (melibiose and
p
-nitrophenyl-α-
d
-galactopyranoside) were not hydrolyzed, activity against ONPG was not dependent upon inorganic phosphate, and galactose was released by cleavage of ONPG. ONPG hydrolysis provided a simple and rapid method for detecting lactose-positive
Neisseria
.
Neutralization of β-Lysin and Cationic Bactericidal Agents by Acidic Phospholipid
Authors: Joos Richard W. , Hall Wendell H.
Published: January 2020

Acidic phospholipids neutralized the antistaphylococcal activity of rabbit, human, and rat serum and purified rabbit β-lysin as well. Several tissue bactericidal factors and cationic antibiotics were also neutralized. The neutralizing ability of all anionic lipids tested, together with the lack of this ability for the electrostatically neutral phosphatidylcholine, suggested that neutralization resulted from formation of electrostatic complexes between negative charges on the lipids and positive charges on the bactericidal substances. The neutralization of these host defense systems by phospholipids can explain the ability of phospholipids to increase bacterial virulence.
Lysis of
Staphylococcus aureus
Cell Walls by a Soluble Staphylococcal Enzyme
Authors: Huff Eskin , Silverman Carol S.
Published: January 2020

Enzyme preparations of
Staphylococcus aureus
were examined for their ability to solubilize
32
P-labeled cell walls of the parent organism. Enzymatic activity was observed in the growth medium, in soluble fractions, and associated with native cell walls. Enzyme associated with isolated cell walls could be inactivated with formaldehyde without reducing the susceptibility of the walls to the action of added enzyme. When cells are frozen and thawed, 50 to 75% of the intracellular enzyme is released along with 2% of the intracellular protein. This freeze-thaw extracted enzyme has little, if any, activity on intact
S. aureus
cells. It appears that the enzyme resides near the cell wall and acts on the cell-wall inner surface.
Chemical and Immunological Studies on Mycobacterial Polysaccharides I. Purification and Properties of Polysaccharides from Human Tubercle Bacilli
Authors: Azuma Ichiro , Kimura Hamako , Niinaka Tohru , Aoki Takakazu , Yamamura Yuichi
Published: January 2020

Defatted human tubercle bacilli, Aoyama B strain, were extracted with 0.1
n
NaOH for 24 hr, and the crude polysaccharide fraction was precipitated by the addition of 5 volumes of ethyl alcohol. A yield of 17.8 g of crude polysaccharides was obtained from 800 g of bacilli. The crude polysaccharide was further fractionated into seven fractions by fractional precipitation with ethyl alcohol. Each fraction was purified by successive chromatography on Dowex 50 and diethylaminoethyl cellulose, and by gel filtration on Sephadex G-75 and G-200. Optical rotation and gas chromatographic analyses of purified polysaccharide showed that these polysaccharides contained glucan mannan, arabinomannan, and arabinogalactan. Each polysaccharide was almost completely free from nitrogen, and no tuberculin reaction was produced by 100 μg of each material. Arabinomannan and arabinogalactan showed precipitin reaction, complement fixation, and passive hemagglutination reaction with rabbit antiserum against heat-killed whole bacilli (Aoyama B). In guinea pigs sensitized with Aoyama B bacilli, arabinomannan and arabinogalactan provoked anaphylactic shock when injected intravenously, and Arthus type reaction when injected intracutaneously. With the use of rabbit antiserum, arabinomannan and arabinogalactan showed passive anaphylactic shock, passive cutaneous anaphylaxis, and Prausnitz-Küstner type reactions in guinea pigs. By immunodiffusion analysis, it was shown that the antigenic determinant of arabinomannan was different from that of arabinogalactan.
Initiation of Deoxyribonucleic Acid Synthesis After Thymine Starvation of
Bacillus subtilis
Authors: Kallenbach Neville R. , Ma Rong-Ine
Published: January 2020

Evidence for premature initiation of deoxyribonucleic acid (DNA) replication after thymine starvation of
Bacillus subtilis
W23T
−
is presented, based on (i) increase in the number of
ade
+
relative to
met
+
transformants yielded by the DNA isolated from cultures after starvation (the
ade
−
marker being near the origin of replication, whereas
met
−
is close to the terminus), and (ii) increase in both the initial rate and final level of tritiated thymine incorporation in the presence of chloramphenicol after release from starvation. The marker ratio data agree quantitatively with the hypothesis that the initiation is induced only on one arm of each chromosome which was replicating prior to starvation.
Separation of Protein Synthesis in Meningopneumonitis Agent from That in L Cells by Differential Susceptibility to Cycloheximide
Authors: Alexander Jennifer J.
Published: January 2020

Cycloheximide had no effect on multiplication of the meningopneumonitis agent in L cells in concentrations which eliminated over 90% of the protein synthesis in the host cells. Infected L cells treated with cycloheximide, however, incorporated labeled amino acids into the trichloroacetic acid-insoluble fraction. This incorporation was attributed to the biosynthetic activity of the meningopneumonitis agent. Synthesis of meningopneumonitis protein was abolished by chloramphenicol and chlortetracycline, inhibitors of bacterial protein synthesis, at concentrations which did not inhibit protein synthesis in L cells. Protein synthesis in the meningopneumonitis agent was sustained at a high rate when the host cells remained viable and declined as the L cells died. Overall host protein synthesis was not inhibited by multiplication of the meningopneumonitis agent.
Thermally Induced Ribonucleic Acid Degradation and Leakage of Substances from the Metabolic Pool in
Staphylococcus aureus
Authors: Allwood M. C. , Russell A. D.
Published: January 2020

The effects of temperatures of 50 and 60 C on log-phase and stationary-phase cell suspensions of
Staphylococcus aureus
are described. There is a leakage of free amino acids, protein, and 260 mμ-absorbing material from both types of cell suspension, and membrane damage, as measured by the intracellular penetration of 8-anilino-1-naphthalene-sulfonic acid, may be partially related to this leakage. Ribonucleic acid (RNA) degradation at any one temperature is virtually the same for both types of cell suspension, proceeding initially at a more rapid rate at 60 C than at 50 C. However, at the lower temperature, there is a secondary breakdown of RNA, which may be the result of enzyme action on a particularly labile RNA fraction. With stationary-phase cell suspensions heated in 1
m
sucrose, there is a more rapid degradation of RNA at 60 C than with cells in water. The results are discussed in relation to the biochemical effects of moist heat on the organism.
Phosphate Dependence of Monosaccharide Transport in
Nocardia
Authors: Cerbón Jorge , Ortigoza-Ferado Jorge
Published: January 2020

Uptake of the monosaccharides
d
-glucose and
d
-mannose by
Nocardia asteroides
and
N. brasiliensis
is dependent on the presence of an adequate phosphate concentration in the environment. When phosphate is replaced by solutions of sodium chloride or potassium chloride of identical ionic strength, there is no sugar uptake. In the presence of iso-osmolar concentrations of sodium arsenate, there is, however, sugar uptake activation. When nonmetabolizable 3-
O
-methyl
d
-glucose is used, most of the sugar taken up can be shown to be in the cell at a concentration never exceeding that of the external medium. Phosphate, or arsenate, seems to be essential for the actual migration of the sugar through the cell envelope. The transport of the nonmetabolizable 3-
O
-methyl glucose also requires phosphate, and the transport seems to be of a type that does not require energy.
Purification and Properties of Lysozyme Produced by
Staphylococcus aureus
Authors: Hawiger J.
Published: January 2020

A method based on cold ethyl alcohol fractionation at different
p
H levels and ionic strengths and on gel filtration on a Sephadex G-200 column was used to concentrate and purify lysozyme from the culture supernatant fluid of
Staphylococcus aureus
strain 524. The final, nondialyzable product exhibited a 163-fold rise in specific activity over that of the starting material. Staphylococcal lysozyme is a glycosidase which splits
N
-acetylamino sugars from the susceptible substrate. Staphylococcal lysozyme was shown to be similar to egg white lysozyme in its optimal temperature for reaction, optimal
p
H, activation by NaCl and Ca
++
ions, inhibition by sodium citrate and ethylenediaminetetraacetate, and inactivation by Cu
++
ions and sodium dodecyl sulfate. It differs from the egg white lysozyme in its temperature susceptibility range (staphylococcal lysozyme is inactivated at 56 C). It acts on whole cells and cell walls of
Micrococcus lysodeikticus
, murein from
S. aureus
524, and cell walls of
S. epidermidis
Zak. The last substrate was not susceptible to the action of egg white lysozyme in the test system used. The mechanism of action of staphylococcal lysozyme seems to be analogous to that of egg white lysozyme; however, the biological specificity of the two enzymes may be different.
Antibody Response and Protection Induced by Immunization with Smooth and Rough Strains in Experimental Salmonellosis
Authors: Kenny Kathryn , Herzberg Mendel
Published: January 2020

The antibody response of mice to a smooth strain ofSalmonella typhimuriumwas shown previously to be extremely rapid and potent. As measured by the complement-mediated bactericidal reaction, it was also found to be highly specific as well as reproducible. Experiments which studied the effects of antigen type (live or heat-killed), antigen dose, and the route of immunization indicated that the most rapid and highest antibody response was achieved with live, smooth organisms injected by the intraperitoneal route. Living vaccines of rough strains of eitherS. typhimuriumorS. enteritidisinduced antibodies directed against the corresponding smooth organisms. The response to the rough strains was apparently due to antibody production rather than to the simple release of preformed natural antibody. The duration of protection conferred by the rough strain vaccines was closely correlated with the endotoxic content of the immunizing strain. Smooth heat-killed vaccines and a rough live vaccine protected against homologous but not heterologous challenge. In contrast, immunization with a smooth live vaccine protected mice against both homologous and heterologous challenge infections. Protection was not due to a local effect in the peritoneal cavity, since mice were also protected against subcutaneous challenge. The secondary antibody response, induced in immunized animals by the virulent challenge infection, was demonstrated to be rapid and potent, and hence a factor to be considered in protection.
Genetic Relationship Among Bacteria Classified as Vibrios
Authors: Basden E. H. , Tourtellotte M. E. , Plastridge W. N. , Tucker J. S.
Published: January 2020

Genetic relatedness among six bacterial strains currently classified as vibrios was determined by biochemical tests, deoxyribonucleic acid base composition analysis, and the detection of nucleic acid homology by the membrane filter method. Varying degrees of genetic homology existed among vibrios having similar base compositions. The bovine isolate which had a substantially different per cent guanine plus cytosine content was shown to be genetically different from the remaining vibrio strains. The use of nucleic acid homology studies in classifying vibrio strains is discussed.
Timing of Enzyme Synthesis During Outgrowth of Spores of
Bacillus cereus
II. Relationship Between Ordered Enzyme Synthesis and Deoxyribonucleic Acid Replication
Authors: Steinberg William , Halvorson Harlyn O.
Published: January 2020

Experiments were carried out to determine whether, during outgrowth of bacterial spores, deoxyribonucleic acid (DNA) replication provided the basis by which ordered transcription was controlled. During outgrowth, significant DNA synthesis does not occur until just prior to the onset of cell division. However, incorporation of radioactive DNA precursors into DNA is observed within 5 to 10 min after the initiation of germination. By employing a thymine-requiring auxotroph and
3
H-bromodeoxyuridine, this incorporation appears to be a result of DNA replication and not repair synthesis. For the following reasons it was concluded that, during outgrowth, transcriptional processes were not ordered by DNA replication. (i) In a thymine auxotroph, thymine addition did not alter the periodicity of induced α-glucosidase and histidase synthesis during outgrowth. (ii) DNA synthesis was inhibited 80% by 5-fluoro-2′-deoxyuridine (FUdR), and, after a 5-min lag, completely by mitomycin C, but these inhibitors exerted a differential effect on induced histidase synthesis. Enzyme synthesis was insensitive to FUdR but was inhibited by mitomycin C, presumably as a result of cross-linking of the complementary DNA strands.
Correlation Between Mutation Type and the Production of Cross-reacting Material in Mutants of theAGene of the Histidine Operon inSalmonella typhimurium
Authors: Margolies Michael N. , Goldberger Robert F.
Published: January 2020

This study concerns the correlation between the type of mutation in a bacterial gene and the ability of the mutant organism to produce immunologically cross-reacting material (CRM). Ninety-five mutants of theAgene of the histidine operon inSalmonella typhimuriumhave been separated into three classes, by means of mutagenesis and suppression tests, according to the classification scheme devised by H. J. Whitfield, Jr., et al.: (i) missense mutants (in which there is a single amino acid substitution in theAprotein); (ii) nonsense mutants (in which various portions of the carboxyl-terminal segment of theAprotein are missing); and (iii) deletion and frameshift mutants. Extracts of all mutants were also examined for the presence of CRM. At least 70% of the missense mutants produced CRM. The genetic loci affected in these mutants were randomly distributed throughout theAgene. None of the nonsense, deletion, or frameshift mutants produced CRM. The absence of CRM in the nonsense mutants is in keeping with the finding that removal of the carboxyl-terminal valine residue from theAprotein by carboxypeptidase A eliminates antigenicity.
Effect of Nalidixic Acid and Hydroxyurea on Division Ability ofEscherichia coli fil+andlon−Strains
Authors: Kantor George J. , Deering R. A.
Published: January 2020

Short periods of incubation in medium containing nalidixic acid or hydroxyurea, followed by a return to normal growth conditions, induced filament formation inEscherichia coliB (fil+) and AB1899NM (lon−) but not in B/r (fil−) and AB1157 (lon+). These drugs reversibly stopped deoxyribonucleic acid (DNA) synthesis with little or no effect on ribonucleic acid (RNA) synthesis or mass increase. The initial imbalance caused by incubation in these drugs was the same for B and B/r as was macromolecular synthesis following a return to normal growth conditions. DNA degradation caused by nalidixic acid was measured and found to be the same for B and B/r. Hydroxyurea caused no DNA degradation in these two strains. Survival curves as determined under various conditions by colony formation suggested that the property of filament formation was responsible for the extrasensitivity offil+andlon−strains to either nalidixic acid or hydroxyurea.E. coliB was more sensitive to either drug than was B/r or Bs-1. Pantoyl lactone or liquid holding treatment aided division and colony formation of nalidixic acid-treated B but had no effect on B/r. Likewise, the filament-former AB1899NM was more sensitive to nalidixic acid than was the non-filament-former AB1157. The sensitivity of B/r and Bs-1to nalidixic acid was nearly the same except at longer times in nalidixic acid, when Bs-1appeared more resistant. Even though nalidixic acid, hydroxyurea, and ultraviolet light may produce quite different molecular alterations inE. coli, they all cause a metabolic imbalance resulting in a lowered ratio of DNA to RNA and protein. We propose that it is this imbalance per se rather than any specific primary chemical or photochemical alterations which leads to filament formation by some genetically susceptible bacterial strains such aslon−andfil+.
Dependence of Diaminopurine Utilization on the Mutational Site of Purine Auxotrophy in
Bacillus subtilis
I. Nutritional Experiments
Authors: Demain Arnold L. , Shigeura Harold T.
Published: January 2020

An attempt was made to explain the puzzling observation that in bacteria 2,6-diaminopurine can replace guanine for guanineless mutants and for xanthineless mutants (both of which can make adenosine monophosphate de novo) but not for nonexacting purine auxotrophs (which cannot make adenosine monophosphate de novo). The analogue failed to inhibit the growth of nonexacting purineless
Bacillus subtilis
MB-1356 growing on guanine. In fact, growth was somewhat stimulated. This eliminated a possible solution involving the inhibition of guanosine monophosphate reductase by a diaminopurine derivative. Sparing of guanine by diaminopurine was matched by an even greater sparing of adenine. Addition of a small amount of adenine to MB-1356 failed to allow unrestricted growth on diaminopurine, thus eliminating a possible solution requiring an adenine derivative for the initial deamination of diaminopurine to guanine. The same degree of sparing of adenine by diaminopurine was observed whether both purines were added together or whether the adenine was added 1 hr after diaminopurine. This eliminated the possibility that diaminopurine was wasted by a “dead-end” conversion in the absence of adenine. Consideration of these nutritional data led to the development of two additional explanations, which are examined by tracer methodology in the following paper.
Role of Galactose or Glucose-1-Phosphate in Preventing the Lysis of
Streptococcus diacetilactis
Authors: Moustafa Hassan H. , Collins E. B.
Published: January 2020

Cells of
Streptococcus diacetilactis
DRCI grown at 32 C in media containing glucose as the energy source were osmotically fragile and began to lyse immediately after growth was stopped (by the action of chloramphenicol or the exhaustion of glucose), unless they were then stabilized by hypertonic medium or spermine or by storage at low
p
H or low temperature, or both. In media containing excess glucose, with growth limited by exhaustion of some nutrient other than the energy source, the appearance of lysis was masked by the occurrence of a balance between lysis and synthesis. The osmotic fragility apparently resulted from inability of the organism to use glucose as an adequate precursor of galactosamine, and conditions of temperature and
p
H that promoted rapid growth on glucose were particularly conducive to the formation of cells that lysed readily. Growing the organism in media containing galactose, lactose, maltose, or glucose (at 17 C) as energy source resulted in the formation of cells that were resistant to lysis and richer in galactosamine than unstable cells formed on glucose at 32 C. The results indicate that the organism phosphorolyzes maltose to glucose plus β-glucose-1-phosphate, and suggest that it can use the β-glucose-1-phosphate in place of α-glucose-1-phosphate in the formation of cell materials.
Morphology and Chemistry of Cell Walls ofMicrococcus radiodurans
Authors: Work Elizabeth , Griffiths Hilary
Published: January 2020

Walls of the pigmented strain ofMicrococcus radioduransshowed several layers in the electron microscope. These layers include an outermost network structure removed by trypsin, a fragile soft layer containing hexagonally packed subunits, and a rigid layer penetrated by numerous holes. The two inner layers were separated by a process of autolysis, trypsin treatment, and gradient centrifugation. The hexagonally packed layer was less dense, pink in color, and it contained carotenoids, lipid, protein, and polysaccharide. The lipid consisted of odd-numbered as well as even-numbered fatty acids, and the polysaccharide contained rhamnose and mannose, but it did not contain heptose. The “holey” layer was white and was composed of a mucopeptide containing glucosamine, muramic acid, and four main amino acids (glutamic acid, alanine, glycine, andl-ornithine, in the ratios of 1:1.7:1.8:1.2, respectively). This layer also contained phosphorus, glucose, and a trace ofmeso- andll-diaminopimelic acid. A white mutant, W1, ofM. radioduranshad no pigment or lipid in its walls, but it contained small amounts of the “hexagonal” layer. The holey layer, constituting the bulk of the wall, was similar in morphology and composition to that layer in the pigmented strain. Lysozyme did not remove the lipoprotein-polysaccharide component from the walls of the pigmented strains, and the hexagonally packed structure was not visibly affected, except for change in a minor structure. Most of the mucopeptide layer was solubilized by lysozyme, but a structureless bag-shaped residue was left. This residue contained phosphorus, carbohydrate, and limited amino acids, but it did not contain muramic acid, glucosamine, or ornithine. Aqueous phenol removed a lipoprotein component from strain R1, which contained limited fatty acids. It also removedmeso- andll-diaminopimelic acid.