bluuebunny/crossref_metadata_2025 huggingface dataset:
Acrylamide Gel Electrophoresis of Intracellular Proteins During Early Stages of Sporulation inBacillus subtilis
Authors: Bott Kenneth F.
Published: January 2020

Acrylamide gel electrophoresis of unfractionated cellular extracts ofBacillus subtilisis shown to be an effective method for characterizing many of the changes in protein composition, when coupled with specific histological-type staining reactions. The results obtained here by using extracts from cells at different stages of growth and sporulation are consistent with observations from other laboratories where extensively purified and highly characterized enzymes have been studied. In several instances, the histochemical reactions can be associated with a specific enzymatic function and appear to indicate the presence of multiple molecular forms. In other instances, the data cannot be evaluated in terms of known enzyme function because the specificity of the histochemical analysis is not certain. However, the assays described permit monitoring of electrophoretic changes at the level of individual proteins within sporulating cultures. The results suggest thatB. subtilismay contain two “hexokinase-like” enzymes which cease to function before sporulation is initiated. Aldolase and alanine dehydrogenase are detectable as single bands of enzyme activity during vegetative growth but as multiple molecular forms once sporulation has been initiated. Reduced nicotinamide adenine dinucleotide dehydrogenase activity is represented by an entire family of reactive species in these crude extracts, which undergo multiple changes during the early stages of sporulation. Tricarboxylic acid cycle dehydrogenase enzymes and those bands having esterase activity on α-naphthyl acetate show detectable changes in specific activity after cessation of exponential growth. Glucose dehydrogenase is not detectable until the sequence of changes leading to spore formation has progressed for 4 or 5 hr.
Comparative Zone Electrophoresis of Enzymes of
Pseudomonas solanacearum
and
Pseudomonas cepacia
Authors: Baptist James N. , Shaw Charles R. , Mandel Manley
Published: January 2020

The technique of starch-gel electrophoresis with specific staining for a series of enzymes was used to compare 21
Pseudomonas
strains representing both
P. cepacia
and
P. solanacearum
. These experiments produced no evidence for close similarity of the two species. Twelve strains of
P. solanacearum
were compared by means of data obtained from nine different enzymes, and the data indicate that these strains belong in two biotypes. Except for the assignment of two strains, these groups are the same as the two major groups previously derived from nutritional properties and from deoxyribonucleic acid hybridization experiments. Eleven enzymes were available for comparisons of the
P. cepacia
strains. Eight of these strains form a homogeneous group, but the last strain, number 249, differs considerably from the other representatives of the species.
Amino Acid-β-Naphthylamide Hydrolysis by
Pseudomonas aeruginosa
Arylamidase
Authors: Riley P. S. , Behal Francis J.
Published: January 2020

The intracellular and constitutive arylamidase from
Pseudomonas aeruginosa
was purified 528-fold by salt fractionation, ion-exchange chromatography, gel filtration, and adsorption chromatography. This enzyme hydrolyzed basic and neutral
N
-terminal amino acid residues from amino-β-naphthylamides, dipeptide-β-naphthylamides, and a variety of polypeptides. Only those substrates having an
l
-amino acid with an unsubstituted α-amino group as the
N
-terminal residue were susceptible to enzymatic hydrolysis. The molecular weight was estimated to be 71,000 daltons. The lowest
K
m
values were associated with substrates having neutral or basic amino acid residues with large side chains with no substitution or branching on the β carbon atom.
Effects of Various Drugs on Hemolytic Activity of
Streptococcus zymogenes
Authors: Werth Jean M. , Jackson Robert W.
Published: January 2020

Drugs known to interrupt the chain of protein synthesis (streptomycin, chloramphenicol, ethidium bromide) appeared to affect production of the group D lysin by
Streptococcus zymogenes
by inhibiting growth. Drugs which block cell wall synthesis (vancomycin, bacitracin,
d
-cycloserine, and phosphonomycin) inhibited lytic activity by a mechanism independent of growth. Bacitracin appeared not to have a major effect on lysin production but elicited the production of an inhibitor of lytic activity.
Phenotypic Restoration by Molybdate of Nitrate Reductase Activity in
chlD
Mutants of
Escherichia coli
Authors: Glaser J. H. , DeMoss J. A.
Published: January 2020

ChlD
mutants of
Escherichia coli
are pleiotropic, lacking formate-nitrate reductase activity as well as formate-hydrogenlyase activity. Whole-chain formate-nitrate reductase activity, assayed with formate as the electron donor and measuring the amount of nitrite produced, was restored to wild-type levels in the mutants by addition of 10
−4
m
molybdate to the growth medium. Under these conditions, the activity of each of the components of the membrane-bound nitrate reductase chain increased after molybdate supplementation. In the absence of nitrate, the activities of the formate-hydrogenlyase system were also restored by molybdate. Strains deleted for the
chlD
gene responded in a similar way to molybdate supplementation. The concentration of molybdenum in the
chlD
mutant cells did not differ significantly from that in the wild-type cells at either low or high concentrations of molybdate in the medium. However, the distribution of molybdenum between the soluble protein and membrane fractions differed significantly from wild type. We conclude that the
chlD
gene product cannot be a structural component of the formate-hydrogenlyase pathway or the formate-nitrate reductase pathway, but that it must have an indirect role in processing molybdate to a form necessary for both electron transport systems.
Chemical Characterization of a New Surface Antigenic Polysaccharide from a Mutant of
Staphylococcus aureus
Authors: Wu Teresa C. M. , Park James T.
Published: January 2020

A mutant of
Staphylococcus aureus
H was isolated by virtue of its inability to agglutinate with antibodies against teichoic acid of
S. aureus
. Immunological studies revealed that the mutant,
S. aureus
T, possessed a new surface antigen in addition to having the antigenic determinant of the wild-type strain, the ribitol teichoic acid. The presence of this additional surface component rendered strain T resistant to staphylococcal typing phages, presumably by masking the phage-receptor sites. The polymer was separated from teichoic acid by chromatography on diethylaminoethyl cellulose and was shown to be composed of two amino sugars,
N
-acetyl-
d
-fucosamine and
N
-acetyl-
d
-mannosamin uronic acid.
Growth ofEscherichia colion Short-Chain Fatty Acids: Growth Characteristics of Mutants
Authors: Salanitro Joseph P. , Wegener Warner S.
Published: January 2020

The parentEscherichia coliK-12 is constitutive for the enzymes of the glyoxylate bypass and adapts to growth on long-chain fatty acids (C12to C18). It does not utilize medium-chain (C6to C11) or short-chain (C4, C5)n-monocarboxylic acids. Several mutants of this strain which grow using short- or medium-chain acids, or both, as the sole carbon source were selected and characterized. One mutant (D1) synthesizes the β-oxidation enzymes constitutively and grows on medium-chain but not on short-chain acids. A second (N3) is partially derepressed for synthesis of these enzymes and grows both on medium-chain and on short-chain acids. Secondary mutants (N3V−, N3B−, N3OL−) were derived from N3. N3V−grows on even-chain but not on odd-chain acids and exhibits a lesion in propionate oxidation. N3B−grows on odd-chain but not on even-chain acids and exhibits no crotonase activity as assayed by hydration of crotonyl-CoA. N3OL−grows on acetate and propionate but does not utilize fatty acids C4to C18; it exhibits multiple deficiencies in the β-oxidation pathway. Growth on acetate of N3, but not of the parent strain, is inhibited by 4-pentenoate. Revertants of N3which are resistant to growth inhibition by 4-pentenoate (N3PR) exhibit loss of ability to grow on short-chain acids but retain the ability to grow on medium-chain and long-chain acids. The growth characteristics of these mutants suggest that in order to grow at the expense of butyrate and valerate,E. colimust be (i) derepressed for synthesis of the β-oxidation enzymes and (ii) derepressed for synthesis of a short-chain fatty acid uptake system.
RecA
+
-Dependent Repair of Gamma-Ray Damage to
Escherichia coli
Does Not Require Recombination Between Existing Homologous Chromosomes
Authors: Bridges B. A.
Published: January 2020

Chemostat-grown
Escherichia coli
showed
recA
+
-dependent resistance to gamma radiation even though between 50 and 75% of the population possessed only a single unreplicated genome, suggesting that recombination between homologous chromosomes before replication is not necessary for manifestation of
recA
+
-dependent resistance to gamma radiation.
Nutritional Requirements of
Arizona, Citrobacter
, and
Providencia
Authors: Machtiger Neal A. , O'Leary William M.
Published: January 2020

The nutritional requirements of
Arizona, Citrobacter
, and
Providencia
are compared, and chemically defined media in which these organisms may be grown are reported.
Substrate Specificity of a Mutant Alanyl-Transfer Ribonucleic Acid Synthetase of
Escherichia coli
Authors: Buckel Peter , Lubitz Werner , Böck August
Published: January 2020

The correlation between the in vivo functioning and the in vitro behavior of the thermolabile alanyl-transfer ribonucleic acid (tRNA) synthetase (ARS) of
Escherichia coli
strain BM113 is presented. As a measure for the ARS activity inside the cell, the amount of acylated tRNA
ala
in vivo was determined. The rapid drop of the per cent tRNA
ala
charged which was observed upon shifting a culture of BM113 to the nonpermissive temperature indicates that in vivo acylation of tRNA
ala
might be the growth-limiting step at high temperature. Since neither growth nor the in vivo charging level of tRNA
ala
was affected by the addition of high
l
-alanine concentrations to the medium, one may infer that impaired functioning of the mutant enzyme at 40 C seems not to be due to reduced affinity of the enzyme for the amino acid. Separation of bulk tRNA of
E. coli
and of yeast on benzoylated diethylaminoethyl cellulose and charging of the fractions of the column by wild-type and mutant ARS reveal that only those tRNA species aminoacylated by the wild-type enzyme are also charged by the mutant ARS. Determination of the
K
m
values of wild-type and mutant ARS for the three isoaccepting tRNA
ala
species of
E. coli
shows a ca. 10-fold increase of the apparent
K
m
values of the mutant enzyme for all three species. Thus, the mutation proportionally reduces the apparent affinity for tRNA
ala
without causing any detectable recognition errors. Investigation of heat inactivation kinetics of wild-type and mutant ARS without and in the presence of substrates provides further evidence that only the transfer site of the ARS is altered by the mutation. Moreover, whereas both enzymes possess the same
p
H optimum of the relative maximal velocity, their
p
H dependence of the
K
m
values for tRNA is different. The
K
m
of the wild-type enzyme decreases at
p
H values below 7.0 and that of the mutant enzyme shows the inverse tendency; this again indicates an alteration of the tRNA binding site.
Growth Characteristics of a Pseudomonad Which Utilizes Pyridoxine or Pyridoxamine as a Carbon Source
Authors: Guirard Beverly M. , Snell Esmond E.
Published: January 2020

Cultural characteristics of
Pseudomonas
MA-1, which has been extensively used as a source of enzymes that degrade vitamin B
6
, confirm its classification as a pseudomonad. The organism requires biotin for growth; any one of several amino acids is also required for growth when pyridoxine (but not when glucose) serves as the energy source. Growth of
Pseudomonas
MA-1 is inhibited by one or more unidentified substances formed when pyridoxine is autoclaved with the medium. Modified cultural conditions are described which permit the large-scale growth of the organism with pyridoxine as carbon source.
Mutants of
Rhodospirillum rubrum
Obtained After Long-Term Anaerobic, Dark Growth
Authors: Uffen R. L. , Sybesma C. , Wolfe R. S.
Published: January 2020

Rhodospirillum rubrum
S
1
cells were grown for more than 100 generations under strict anaerobic, dark conditions in liquid medium with sodium pyruvate. During this time, growth became nonpigmented. When cells were streaked onto the surface of solid growth medium in anaerobic bottles and placed in the dark, a few light-red colonies developed, but the majority was nonpigmented. Mutants were obtained from colonies selected on the basis of pigmentation and bacteriochlorophyll
a
content. The growth, ultrastructure, and light reactivity of two mutants were examined. Mutant C synthesized bacteriochlorophyll
a
(7.2 μmoles per mg of protein), altered membrane structures, and chromatophores during dark growth. Examination of light-induced changes of the absorption spectrum of this mutant suggested that only an electron transport pathway, which included the low potential cytochrome-like pigment C428, could be detected. Mutant C grew anaerobically in the light, whereas mutant G1 was light sensitive and produced only trace amounts of bacteriochlorophyll
a
(0.6 μmole per ml of protein). Poorly pigmented G1 cells contained unusual membrane structures. When dark-grown G1 colonies were placed in the light, deep-red colored papillae developed in the nonpigmented colonies. During anaerobic, dark growth with sodium pyruvate, both C and G1 synthesized poly-β-hydroxybutyrate and produced acetate, carbon dioxide, and hydrogen gas.
Lack of Distinction Between
Nitrobacter agilis
and
Nitrobacter winogradskyi
Authors: Pan Pauline H. C.
Published: January 2020

No adequate criteria were established to distinguish between
Nitrobacter agilis
and
N. winogradskyi
. However, very gentle preparative techniques permitted demonstration of flagella in
N. agilis
.
Biosynthesis of Cholesteryl Glucoside by
Mycoplasma gallinarum
Authors: Smith Paul F.
Published: January 2020

The biosynthesis of cholesteryl glucoside by
Mycoplasma gallinarum
strain J proceeds by the transfer of glucose from uridine-5′-diphosphoglucose to membrane-bound sterol. Galactose also can be coupled to cholesterol via uridine-5′-diphosphogalactose. The reaction is specific for the uridine-5′-diphospho sugars. Enzymatic activity is associated with the membrane. Treatment of the membrane to remove endogenous sterol inactivates the enzyme. Only sterol which has been bound to the membrane participates in the reaction. The optimum
p
H is about 8.0, and Mg
2+
is required. The reaction is unaffected by nucleotide triphosphate, uridine-5′-monophosphate, and uridine-5′-diphosphate. Reduction of
p
H to the optimum for β-glucosidase in the membrane results in loss of synthesized glucoside. The enzyme is saturated at 0.5 m
m
uridine-5′-diphosphoglucose. The apparent
K
m
of 2.05 × 10
−7
indicates a high affinity of the enzyme for the nucleotide sugar.
Regulation of Staphylococcal Penicillinase Synthesis
Authors: Imsande John , Zyskind Judith W. , Mile Imre
Published: January 2020

5-Methyl tryptophan was found to be an efficient inducer of penicillinase synthesis in
Staphylococcus aureus
. Addition of actinomycin D or tryptophan to the culture medium shuts off the 5-methyl tryptophan-induced synthesis of penicillinase with an apparent half-life of approximately 1 to 2 min, respectively. Hence, in the induction of penicillinase synthesis, 5-methyl tryptophan seems to function as a structural analogue of penicillin rather than by becoming incorporated in proteins and thereby creating faulty penicillinase repressor or antirepressor. This conclusion is supported by similarities in the structures of the two compounds as revealed by solid atomic models. The fact that
S. aureus
exposed to
14
C-penicillin in the absence of protein synthesis failed to synthesize penicillinase at an increased level when cell growth was resumed strongly suggests that a protein involved in the regulation of penicillinase synthesis must be synthesized in the presence of the penicillinase inducer. In turn, this observation suggests that the penicillinase inducer promotes penicillinase synthesis by directing the penicillinase regulatory protein (i.e., the penicillinase antirepressor) to acquire a different conformation when it is synthesized in the presence of the penicillinase inducer. A working model for the regulation of penicillinase synthesis based on these and other data has been constructed and is presented.
Effects of Phenethyl Alcohol on Phospholipid Metabolism in
Escherichia coli
Authors: Nunn William D. , Tropp Burton E.
Published: January 2020

The incorporation of labeled precursors into the deoxyribonucleic acid, ribonucleic acid (RNA), proteins, and phospholipids of
Escherichia coli
cultured in the presence of phenethyl alcohol (PEA) was determined. PEA inhibited the uptake of labeled uracil to the same extent in cells exhibiting relaxed and stringent control of RNA synthesis. This indicates that PEA does not primarily affect amino acid synthesis or activation. Uptake of labeled acetate into the phospholipid fraction was more sensitive to inhibition by low concentrations of PEA than was the uptake of labeled precursors into the macromolecules. Thymine starvation or the addition of nalidixic acid (10 μg/ml) had no effect on acetate incorporation. Chloramphenicol (25 μg/ml) was a much less effective inhibitor of acetate incorporation than was PEA. The distribution of labeled acetate incorporated into phospholipids was markedly affected by the presence of PEA. The uptake of acetate into phosphatidylethanolamine and phosphatidylglycerol was inhibited, whereas the uptake of acetate into the cardiolipin fraction was unaffected. Since acetate incorporation into phospholipid was quite sensitive to PEA, we suggest that the PEA-sensitive component required for the initiation of replication may be a phospholipid(s).
Transport of Lysine and Hydroxylysine in
Streptococcus faecalis
Authors: Friede J. D. , Gilboe D. P. , Triebwasser K. C. , Henderson L. M.
Published: January 2020

Data are presented which support the view that
l
-lysine is transported by two systems in
Streptococcus faecalis
. The system with the higher affinity for
l
-lysine appears to be specific for
l
-lysine among the common amino acids and to require an energy source. The second system transports both
l
-lysine and
l
-arginine and does not appear to require an energy source. Both of these systems will accept hydroxy-
l
-lysine as a substrate as shown by the energy requirement for hydroxy-
l
-lysine transport and by the inhibition of uptake by
l
-arginine as well as by
l
-lysine. The affinity of both systems appears to be considerably lower for hydroxy-
l
-lysine than for
l
-lysine. A mutant of
S. faecalis
which is resistant to the growth inhibitory action of hydroxy-
l
-lysine appears to differ from the parent strain by having a defective
l
-lysine-specific transport system. In this mutant, hydroxy-
l
-lysine is not readily transported via the
l
-lysine-specific system because of the mutation or via the second system because of the high concentration of
l
-arginine present in the growth medium. This overall lack of transport prevents hydroxy-
l
-lysine from reaching inhibitory levels within the cell.
Response of
Escherichia coli
B/r to High Concentrations of Sucrose in a Nutrient Medium
Authors: Scheie Paul O. , Rehberg Rita
Published: January 2020

Escherichia coli
B/r was subjected to sucrose concentrations up to 1
m
in the presence of Nutrient Broth. Plasmolysis seldom was evident 2 min after this treatment. The subsequent response was characterized by transient decreases in optical density as well as changes in appearance as seen under phase optics. No transient effects were detected in the synthetic rates or in the division of the survivors.
Enzymatic Basis for Differentiation of
Rhizobium
into Fast- and Slow-Growing Groups
Authors: Drets G. Martinez-De , Arias A.
Published: January 2020

Glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and other enzymes related to carbohydrate metabolism were studied in rhizobia. A nicotinamide adenine dinucleotide phosphate-6-phosphogluconate dehydrogenase was detected in strains of the fast-growing group of
Rhizobium
but not in strains of the slow-growing group. An enzymatic differentiation of rhizobia was established.
Nutritional Studies of
Rickettsia quintana
: Nature of the Hematin Requirement
Authors: Myers William F. , Osterman Joseph V. , Wisseman Charles L.
Published: January 2020

Rickettsia quintana
grew in a liquid medium consisting of a brain-heart infusion base supplemented with starch and hematin. The growth requirement for hematin could not be substituted by compounds of known catalytic activity for H
2
O
2
, viz., catalase, potassium pyruvate, or charcoal, or by the reducing compounds sodium sulfite and sodium thioglycollate.
R. quintana
was catalase-negative, but no H
2
O
2
production could be demonstrated by the catalase-aminotriazole technique. A minimum inoculum giving 10
5
cells/ml was required to initiate growth. The generation time at 33 C was 10 hr. The temperature range for growth was 28 to 37 C. Growth was enhanced when succinate or glutamate was added as energy source.
Nature of Deoxyribonucleic Acid Synthesis and Its Relationship to Protein Synthesis During Outgrowth of
Bacillus cereus
T
Authors: Rana Rajendra S. , Halvorson Harlyn O.
Published: January 2020

Deoxyribonucleic acid (DNA) synthesis during early outgrowth of spores of
Bacillus cereus
T (
thy
−
) has been examined.
14
C-thymidine incorporated begins 2 to 5 min after germination and continues at a slow rate up to 30 min, after which the rate of
14
C-thymidine incorporation increases considerably. Early DNA synthesis up to 30 min after germination is dependent upon simultaneous protein synthesis. The examination of the stability of proteins synthesized soon after germination shows that they are susceptible to intracellular degradation. The evidence provided here indicates that protein degradation is the cause of observed dependence of DNA synthesis on simultaneous protein synthesis. The DNA synthesis occurring soon after germination is primarily a repair type synthesis which is followed by the onset of normal replication approximately 30 min after germination.
Total Synthesis of Acetate from CO
2
V. Determination by Mass Analysis of the Different Types of Acetate Formed from
13
CO
2
by Heterotrophic Bacteria
Authors: Schulman Marvin , Parker Donald , Ljungdahl Lars G. , Wood Harland G.
Published: January 2020

Mass analysis was used to determine the amount of acetate which is totally synthesized from
13
CO
2
during fermentations by
Clostridium formicoaceticum, C. acidiurici, C. cylindrosporum, Butyribacterium rettgeri
, and
Diplococcus glycinophilus
. In the fermentation of fructose by
C. formicoaceticum
, 27% of the acetate was found to be totally synthesized from CO
2
, and the remaining acetate was unlabeled, having been formed from fructose. Evidence is presented that the purine-fermenting organisms,
C. acidiurici
and
C. cylindrosporum
, totally synthesized about 9% of the acetate from CO
2
, and that the methyl group of an additional 9% was formed from CO
2
. The remaining acetate was formed from the carbons of the purine and not via CO
2
. It has been postulated that the fermentation of the purines and synthesis of acetate from CO
2
both occur via derivatives of tetrahydrofolate. Evidence is presented that a compartmentalization of these folate intermediates is required if both the purine degradation and the CO
2
utilization involve identical intermediates. Neither
B. rettgeri
nor
D. glycinophilus
incorporated sufficient
13
CO
2
into acetate to allow determination of the types of acetate by mass analysis, although they did incorporate labeled
14
CO
2
in both positions of acetate.
Dependence of Ribonucleic Acid Synthesis on Continuous Protein Synthesis in Yeast
Authors: Roth R. M. , Dampier C.
Published: January 2020

Using an auxotrophic strain of
Saccharomyces cerevisiae
, we examined the kinetics of ribonucleic acid (RNA) synthesis following inhibition of protein synthesis caused by amino acid starvation or cycloheximide. Removal of a required amino acid immediately stopped net protein synthesis. After a brief lag, RNA synthesis also ceased. Cycloheximide, a ribosome-inhibiting drug, also immediately halted net protein synthesis. Again RNA synthesis stopped after a brief lag. Although cycloheximide and amino acid starvation affect different steps in protein biosynthesis, both inhibited RNA synthesis in identical fashion. This indicates that amino acids do not play a unique role in the control of RNA production in rapidly growing yeast; rather, it suggests that RNA synthesis is responsive to the overall rate of protein synthesis itself.
Sporulation of Tricarboxylic Acid Cycle Mutants of
Bacillus subtilis
Authors: Yousten Allan A. , Hanson Richard S.
Published: January 2020

A mutant of
Bacillus subtilis
168 lacking aconitase (EC 4.2.1.3) was found to be blocked at stage 0 or I of sporulation. Although adenosine triphosphate levels, which normally decrease in tricarboxylic acid cycle mutants at the completion of exponential growth, could be maintained at higher levels by feeding metabolizable carbon sources, this did not permit the cells to progress further into the sporulation sequence. When post-exponential-phase cells of mutants blocked in the first half of the tricarboxylic acid cycle were resuspended with an energy source in culture fluid from post-exponential-phase wild-type
B. subtilis
or
Escherichia coli
, good sporulation occurred. The spores produced retained the mutant genotype and were heat stable but lost refractility and heat stability several hours after their production.
Apical Vesicles in Growing Bud Cells of Heterobasidiomycetous Yeasts
Authors: McCully E. Kathleen , Bracker Charles E.
Published: January 2020

Clusters of cytoplasmic vesicles resembling those in growing hyphal apices of mycelial fungi are found near the tips of buds in three heterobasidiomycetous yeasts,
Rhodotorula glutinis, Candida scottii
, and
Sporobolomyces salmonicolor
.
Regulation of Synthesis of Methionyl-, Prolyl-, and Threonyl-Transfer Ribonucleic Acid Synthetases of
Escherichia coli
Authors: Archibold E. R. , Williams L. S.
Published: January 2020

Proline- and threonine-restricted growth caused a three- to fourfold derepression of the differential rate of synthesis of the prolyl- and threonyl-transfer ribonucleic acid (tRNA) synthetases, respectively. Similarly, there was approximately a 24-fold derepression in the rate of synthesis of methionyl-tRNA synthetase during methionine restriction. Addition of the respective amino acids to such derepressed cultures resulted in a repression of synthesis of their cognate synthetases. These results support previous findings and further strengthen the idea that the formation of aminoacyl-tRNA synthetases is regulated by some mechanism which is mediated by the cognate amino acids.
Altered Phospholipid Metabolism in a Sodium-Sensitive Mutant of
Escherichia coli
Authors: Lusk Joan E. , Kennedy Eugene P.
Published: January 2020

A mutant of
Escherichia coli
has been isolated, the growth of which is inhibited by low concentrations (1 m
m
) of NaCl. High levels of magnesium, calcium, or strontium in the medium permit growth in the presence of sodium. The metal content of the inhibited mutant is normal, but the strain is unable to tolerate levels of sodium to which the wild type is indifferent. Immediately after the addition of sodium to cultures of the mutant, rates of synthesis of protein, ribonucleic acid, deoxyribonucleic acid, and total lipid are unchanged, but more cardiolipin and less phosphatidylethanolamine are produced. The direct enzymatic cause of this change, which affects membrane function, is not known. Studies of the metabolism of phosphatidylglycerol in vivo after pulse-labeling with [2-
3
H
]glycerol reveal that a major pathway both in wild-type and mutant strains involves the cleavage of labeled glycerol from phosphatidylglycerol.
Isolation and Partial Characterization of Regulatory Mutants of the Pyrimidine Pathway in
Salmonella typhimurium
Authors: O'Donovan Gerard A. , Gerhart John C.
Published: January 2020

Mutants of
Salmonella typhimurium
affected in the regulation of pyrimidine biosynthesis were isolated by two methods. The first involved screening for bacteria able to feed a pyrimidine-requiring indicator strain, and the second involved selection for bacteria simultaneously resistant to two pyrimidine analogues, 5-fluorouracil and 5-fluorouridine, in a
S. typhimurium
strain unable to degrade 5-fluorouridine. Among the mutants isolated by these methods are constitutive mutants, producing high levels of pyrimidine biosynthetic enzymes in the presence or absence of pyrimidines, and feedback modified mutants, in which aspartate transcarbamylase is partially desensitized to its inhibitor, cytidine triphosphate. No fully desensitized mutant has been found. The partially desensitized character cotransduces with the
pyrB
locus, that of aspartate transcarbamylase. The constitutive character has been determined in a few cases to be localized in the region of
leu
and
pro
on the
Salmonella
map.
Model for Branch Initiation in
Aspergillus nidulans
Based on Measurements of Growth Parameters
Authors: Katz Dvorah , Goldstein Dinah , Rosenberger R. F.
Published: January 2020

The rate of hyphal elongation and the number of branches per hypha were measured on short sporelings of
Aspergillus nidulans
growing at different rates. The rate of elongation was proportional to total length in unbranched and branched hyphae. At each growth rate, the number of branches per hypha increased with increasing length and gave approximately straight-line graphs when plotted against length. The average number of branches per unit of hyphal length was quite different for the various growth rates and increased in direct proportion to the growth rate. The results are interpreted to mean that (i) growing tips have a maximum rate at which they can elongate and which is reached at hyphal lengths characteristic of the particular growth rate and (ii) a new branch is formed when the capacity of the hypha to elongate exceeds that of the existing tips.
Acid-Soluble Nucleotides in an Asporogenous Mutant of
Bacillus subtilis
Authors: Chow C. T. , Takahashi I.
Published: January 2020

An asporogenous mutant of
Bacillus subtilis
Sp
−
H12-3, which is considered to have a block at stage 0, showed general growth characteristics similar to those of sporulating cultures. However, a sudden increase in the total amount of acid-soluble nucleotides observed at t
2
in sporulating bacteria was completely absent in this mutant. In sporulating cells, a marked increase in two nucleotides which were identified to be uridine diphosphate (UDP)-galactose and UDP-
N
-acetylglucosamine was noted, whereas UDP-glucose appeared to be accumulated in the mutant cells at t
2
. No unusual nucleotides were found in the strains of
B. subtilis
examined. The possible role of these UDP derivatives in early stages of sporulation in
B. subtilis
is discussed.
Morphokinetic Reaction of Cells of
Streptococcus faecalis
(ATCC 9790) to Specific Inhibition of Macromolecular Synthesis: Dependence of Mesosome Growth on Deoxyribonucleic Acid Synthesis
Authors: Higgins Michael L. , Daneo-Moore Lolita
Published: January 2020

The application of quantitative electron microscopy to thin sections of cells of
Streptococcus faecalis
specifically inhibited for deoxyribonucleic acid (DNA), ribonucleic acid, and protein synthesis shows that septal mesosomes (i) increase in size when protein synthesis is inhibited by at least 80% while DNA synthesis proceeds at no less than 50% of the control rate and (ii) decrease in size when DNA synthesis is inhibited 50% or more during the initial 10 min of treatment. This indicates that fluctuations in mesosome size are dependent on the extent of DNA synthesis. The fluctuations in mesosome areas observed on treatment do not correlate with the kinetics of glycerol incorporation per milliliter of a culture. However, when glycerol incorporation is placed on a per cell basis, a strong correlation is observed between increases in (i) the thickness of the electron-transparent layer of the cytoplasmic membrane and (ii) the amount of glycerol incorporated per cell. It seems that the electron-transparent membrane layer may thicken to accommodate changes in lipid content when protein and lipid synthesis are uncoupled.
Effect of Proteolytic Enzymes on Bacterial Flagella
Authors: Martinez Rafael J. , Shaper Joel H. , Lundh Nancy P. , Bernard Patricia D. , Glazer A. N.
Published: January 2020

Sheared flagella of
Salmonella typhimurium
strains SL 870 (Nml
+
Fla
+
) and SL 871 (Nml
−
Fla
+
) were found to be susceptible to proteolytic digestion by trypsin, chymotrypsin, and Pronase. The rate of tryptic digestion was similar for the ε-
N
-methyllysine-containing and the nonmethylated flagella. Thin fibers, which appeared to originate from only one end of the flagellar filament, were formed upon trypsin digestion. The fibers were not dissociated at extremes of
p
H or upon heating. The amino acid composition of the purified fibers was very different from that of intact
Salmonella
flagellin, and the fibers did not cross-react with antiflagellin or antiflagellar antiserum. The possible significance of these findings is discussed in relation to the flagellar structure.
Ultrastructural Studies on a Mutant of
Bacillus subtilis
Whose Growth is Inhibited Due to Insufficient Autolysin Production
Authors: Fan David P. , Beckman Mary M. , Cunningham William P.
Published: January 2020

The growth of
Bacillus subtilis
mutant βA177 can be inhibited under special conditions in which not enough autolytic enzymes are produced for optimal growth. Electron microscopy studies show that during growth inhibition there is localized thickening of the cell wall at positions where cells bend. A model is proposed to explain this result. Rapid growth can be restored by adding lysozyme or a
B. subtilis
autolysin mixture to a growth-inhibited βA177 culture. Such addition reduces the localized wall thickening and causes other changes in surface morphology which are described and discussed. Septum formation seems to be relatively less inhibited than cell elongation when lytic enzyme levels are reduced. Measurements were made demonstrating that walls at ends of cells are morphologically different from walls at sides of cells in cultures of βA177 growing at 51 C.
New Centrifugation Technique for Isolating Enzymes from Large Cell Structures: Isolation and Characterization of Two
Bacillus subtilis
Autolysins
Authors: Fan David P. , Beckman Mary M.
Published: January 2020

Bacillus subtilis
cell walls can be centrifuged through a linear gradient of 0 to 2
m
LiCl and 10 to 25% sucrose so that different autolysins are removed by different salt concentrations and banded in separate positions as the walls pass through the gradient. Using this technique we have found that
B. subtilis
cell walls are isolated with two autolytic enzymes attached. One autolysin, a glycosidase, can be eluted from walls with 0.5
m
LiCl, has a
p
H optimum between 5 and 8, is relatively heat-sensitive, and has a molecular weight of 60,000. The other autolysin, an alanine amidase, can be eluted from walls with 1.5
m
LiCl, has a
p
H optimum around 8, is relatively heat-stable, has a molecular weight of 35,000, and is present in quantities ten times greater than the glycosidase.
Size Distribution of Bacterial Cells
Authors: Stull V. R.
Published: January 2020

By using differential light-scattering measurements of single cells suspended in a laser beam, an effective cell radius has been determined for 141 individual bacteria from suspensions of
Staphylococcus epidermidis
. The accumulation of these measurements has provided the size distribution for the sampling.
Deoxyribonucleic Acid-Protein Ratio and Radioresistance in
Micrococcus radiodurans
Authors: Freedman M. L. , Bruce A. K.
Published: January 2020

Cessation of exponential growth of
Micrococcus radiodurans
heightens X-radioresistance while either increasing or decreasing the deoxyribonucleic acid-protein ratio.
Manganese-Resistant Mutants of
Escherichia coli
: Physiological and Genetic Studies
Authors: Silver Simon , Johnseine Paula , Whitney Eleanor , Clark Dan
Published: January 2020

Manganese is growth inhibitory for
Escherichia coli
. The manganese concentration required for inhibition is dependent upon the magnesium concentration of the medium. Mutants have been isolated which are partially resistant to manganese inhibition in both liquid and solid media. From conjugation experiments, the genetic locus for manganese-resistance,
mng
, appears to be between 34 and 37 min on the
E. coli
genetic map. Experiments with radioactive
28
Mg lead to the tentative conclusion that the
mng
mutants are altered in the inhibition constant for manganese as a competitive inhibitor for the mangnesium accumulation system. Once high manganese enters the cells, it displaces internal magnesium and leads to a net cellular loss and hence growth inhibition. The
mng
mutants are somewhat less subject to manganese-induced magnesium loss under comparable conditions than are manganese-sensitive wild-type cells.
Isolation and Characterization of
Microsporum gypseum
Lysosomes: Role of Lysosomes in Macroconidia Germination
Authors: Page W. J. , Stock J. J.
Published: January 2020

Three types of lysosomes containing either acid protease, alkaline protease, or phosphodiesterase were isolated from a
Microsporum gypseum
macroconidial homogenate on Ficoll gradients. The acid protease was contained in an assimilative lysosome since its activity was affected by the complexity of the exogenous nitrogen source. Ultracentrifugation and electron microscopy revealed that the alkaline protease-containing vesicles were associated with the spore coat material prior to macroconidial germination. During macroconidial germination, zones of spore coat hydrolysis were seen surrounding these vesicles. Other larger vesicles, believed to contain the phosphodiesterase, were also observed in the spore coat during macroconidial germination.
Dependence of the Rate of Synthesis of Phosphatidylethanolamine and Phosphatidylglycerol on the Rate of Growth of
Escherichia coli
Authors: Ballesta J. P. G. , Schaechter M.
Published: January 2020

The rates of synthesis of phosphatidylethanolamine and phosphatidylglycerol vary inversely with the rate of growth of
Escherichia coli
.
Characterization of
S
-Adenosylmethionine: Ribosomal Ribonucleic Acid-Adenine (N
6
-) Methyltransferase of
Escherichia coli
Strain B
Authors: Sipe Jerry E. , Anderson W. Marshall , Remy Charles N. , Love Samuel H.
Published: January 2020

This study is concerned with the isolation and characterization of the enzyme,
S
-adenosylmethionine:ribosomal ribonucleic acid-adenine (N
6−
) methyl-transferase [rRNA-adenine (N
6
-) methylase] of
Escherichia coli
strain B, which is responsible for the formation of N
6
-methyladenine moieties in ribosomal ribonucleic acids (rRNA). A 1,500-fold purified preparation of the species-specific methyltransferase methylates a limited number of adenine moieties in heterologous rRNA (
Micrococcus lysodeikticus
and
Bacillus subtilis
) and methyl-deficient homologous rRNA. The site recognition mechanism does not require intact 16 or 23
S
rRNA. The enzyme does not utilize transfer ribonucleic acid as a methyl acceptor nor does it synthesize 2-methyladenine or N
6
-dimethyladenine moieties. Mg
2+
, spermine, K
+
, and Na
+
increase the reaction rate but not the extent of methylation; elevated concentrations of the cations inhibit markedly. The purified preparations utilize 9-β-ribosyl-2,6-diaminopurine (DAPR) as a methyl acceptor with the synthesis of 9-β-ribosyl-6-amino-2-methylaminopurine. A comparison of the two activities demonstrated that one methyltransferase is responsible for the methylation of both DAPR and rRNA. This property provides a sensitive assay procedure unaffected by ribonucleases and independent of any specificity exhibited by rRNA methyl acceptors.
Differential Sensitivities of the Two Malate Dehydrogenases and the Maltose Permease to the Effect of Glucose in
Saccharomyces carlsbergensis
Authors: Van Rijn J. , Van Wijk R.
Published: January 2020

In
Saccharomyces carlsbergensis
the two malate dehydrogenase activities, which are localized in different compartments of the cell, were found to differ in their response to glucose. The cytoplasmic malate dehydrogenase activity appears to be sensitive to inactivation by very low concentrations of glucose. The mitochondrial malate dehydrogenase activity is only repressed at a higher glucose concentration. Maltose permease is also sensitive to inactivation by glucose. Conditions were found such that the maltose permease was present while the cytoplasmic malate dehydrogenase was inactivated. The different sensitivities of the two malate dehydrogenases and maltose permease to the effect of glucose may explain the preferential use of glucose, maltose, and products of glucose metabolism (2- and 3-carbon skeletons) as carbon sources for growth in the order as mentioned.
Mutations in R Factors ofEscherichia coliCausing an Increased Number of R-Factor Copies per Chromosome
Authors: Nordström Kurt , Ingram Lewis C. , Lundbäck Annika
Published: January 2020

A mutant of the repressed R factor R1a and two mutants of the derepressed R factor R1drd-19showing a two- to fourfold increase in resistance to all of the antibiotics to which the wild-type R factors mediate resistance were studied. The increased resistance was due to a two- to fourfold increase in the number of R-factor copies per chromosome. The production of drug-metabolizing enzymes was linearly correlated to the gene dosage. There was also a linear correlation between resistance to the drugs and the production of the corresponding enzymes. The mutations were also expressed inProteus mirabilisPM1. InProteus, R factors are split into two plasmids, resistance transfer factor and the resistance part. The mutation in one of the mutant R factors seems to be located in the resistance part. A second fi+R factor (R100) was introduced into strains already carrying R1drd-19or the mutant R factor R1drd-19B2. In the first case, R100 and R1drd-19segregated with equal probability when the bacteria were grown on antibiotic-free medium, whereas, in the second case, R100 was rapidly and preferentially excluded.
Physiological Studies of Methane- and Methanol-Oxidizing Bacteria: Comparison of a Primary Alcohol Dehydrogenase from
Methylococcus capsulatus
(Texas Strain) and
Pseudomonas
Species M27
Authors: Patel R. N. , Bose H. R. , Mandy W. J. , Hoare D. S.
Published: January 2020

A primary alcohol dehydrogenase has been purified from
Methylococcus capsulatus
(Texas strain). The purified enzyme catalyzes the oxidation of methanol and formaldehyde to formate; other primary alcohols are oxidized to their corresponding aldehydes. Ammonium ions are required for enzyme activity. The enzyme has a molecular weight of 120,000 daltons and consists of two 62,000 molecular-weight subunits which dissociate at acidic
p
H. The enzyme is similar to an alcohol dehydrogenase enzyme isolated from
Pseudomonas
sp. M27.
Golgi Apparatus in the Postmeiotic Basidium of
Coprinus lagopus
Authors: McLaughlin David J.
Published: January 2020

A golgi apparatus believed to be involved in basidiospore formation has been found in
Coprinus lagopus
following meiosis in the basidium.
Clostridium barkeri
sp. n
Authors: Stadtman E. R. , Stadtman Thressa C. , Pastan Ira , Smith Louis Ds.
Published: January 2020

Clostridium barkeri
sp. n. has been described, and its relationship to other clostridia is discussed.
Effect of Temperature on the Respiration and Cytochromes of an Extreme Thermophile
Authors: McFeters Gordon A. , Ulrich J. Terry
Published: January 2020

The rate of oxygen uptake in an extreme thermophile at 70 C was three times greater than at 50 C. Cytochromesa, b, andcwere present in cells grown at 50, 60, and 70 C. The content of these electron transport system elements remained relatively constant as the growth temperature was raised.
Multiple Regulator Gene Control of the Galactose Operon in
Escherichia coli
K-12
Authors: Hua Sui-Sheng , Markovitz Alvin
Published: January 2020

Previous studies showed that nonsense mutations in either of two genes (
capR
or
capS
) or an undefined mutation in a third gene (
capT
) led to pleiotropic effects: (i) increased capsular polysaccharide synthesis (mucoid phenotype); (ii) increased synthesis of enzymes specified by at least four spatially separated operons involved in synthesis of capsular polysaccharide including the product of the
galE
gene, UDP-galactose-4-epimerase (EC 5.1.3.2) in
capR
mutants. The present study demonstrated that the entire galactose (
gal
) operon (
galE, galT
, and
galK
) is derepressed by mutations in either the
capR
or the
capT
genes, but not by mutation in
capS
. Double mutants (
capR9 capT
) were no more derepressed than the
capR9
mutant, indicating that
capR9
and
capT
regulate the
gal
operon via a common pathway. Isogenic double mutants containing either
galR
+
,
galR
−
,

galR
s

, or

galO
c

in combination with either
capR
+
or
capR9
were prepared and analyzed for enzymes of the
gal
operon. The results demonstrated that
capR9
caused derepression as compared to
capR
+
in all of the combinations. Strains with a

galR
s

mutation are not induced, for the
gal
operon, by any galactose compound including
d
-fucose, and this was confirmed in the present study using
d
-fucose. Nevertheless, the derepression of

galR
s
capR9

compared to

galR
s
capR
+

was four- to sixfold. The same derepression was observed when
galR
+
capR9
was compared to
galR
+
capR
+
. The data eliminate the explanation that internal induction of the
gal
operon by a galactose derivative was causing increased
gal
operon enzyme synthesis in
capR
or
capT
mutants. Furthermore, the same data suggest that the
galR
and
capR
genes are acting independently to derepress the
gal
operon. A modified model for the structure of the
gal
operon is proposed to explain these results. The new feature of the model is that two operator sites are suggested, one to combine with the
galR
repressor and one to combine with the
capR
repressor.
Ultrastructure of Nematode-Trapping Fungi
Authors: Heintz C. E. , Pramer David
Published: January 2020

Capture cells differ ultrastructurally from vegetative cells in the nematode-trapping fungi,
Dactylella drechslerii, Monacrosporium rutgeriensis
and
Arthrobotrys dactyloides
, which capture prey by means of adhesive knobs, adhesive hyphal networks, and constricting rings, respectively. Adhesive knobs and adhesive networks contain dense inclusions not found in hyphal tips or subapical regions of the vegetative hyphae, and rough- and smooth-surfaced membranes are abundant in these trap cells. The fine structure of constricting rings differs from that of adhesive traps, and it is altered by closure. In the open configuration, there are membrane-bound inclusions, labyrinthine networks, and electron-lucent regions between the protoplasts and cell wall, all localized on the luminal side of the ring cells. After closure, these features no longer are evident and the cytoplasm of trap cells stains less densely.