bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship Between the Location of Autolysin, Cell Wall Synthesis, and the Development of Resistance to Cellular Autolysis in
Streptococcus faecalis
After Inhibition of Protein Synthesis
Authors: Pooley Harold M. , Shockman Gerald D.
Published: January 2020

Ten minutes after inhibition of protein synthesis with chloramphenicol (CAP) the ability of cells of
Streptococcus faecalis
(ATCC 9790) to autolyze decreased to less than 20% of the rate for exponential-phase cells. After threonine exhaustion, the time for a 50% drop in the rate of cellular autolysis was about 20 min. These rapid increases in resistance to cellular autolysis could not be accounted for by: (i) the relatively slow and small overall decrease in susceptibility of isolated cell walls to added autolysin, or (ii) a decreased content of either the active or latent (proteinase activatable) form of the autolysin in the wall fraction. Continued wall synthesis resulted in dilution of preexisting autolysin in the isolated wall fraction. The release of labeled “old” relative to “new” wall from CAP-treated cultures showed that wall synthesis shifted away from the areas of wall previously shown to be associated with wall synthesis (extension) in exponential-phase cells. A corresponding dispersal of active autolysin activity was not observed. By using actinomycin D and CAP, a requirement for ribonucleic acid and protein synthesis early in the recovery of cells from amino acid starvation was demonstrated for the recovery in the ability of cells to autolyze. Evidence was obtained which suggests that a protein is involved in the conversion of latent to active autolysin. During recovery from amino acid starvation, increase in wall synthesis and content of active autolysin was delayed (25 to 35 min), whereas an increase in turbidity and latent enzyme content began within 10 min. After treatment with CAP at 22 or 52 min of recovery, a further increase in levels of both active and latent autolysin was severely inhibited; however, the increase in rate of wall synthesis was indistinguishable from that of an untreated control. This suggests that an increase in rate of wall synthesis does not depend on an increase in level of active autolysin.
Site of Initiation of Cellular Autolysis in
Streptococcus faecalis
as Seen by Electron Microscopy
Authors: Higgins M. L. , Pooley H. M. , Shockman G. D.
Published: January 2020

Low concentrations of glutaraldehyde (0.1% or higher) blocked cellular and wall autolysis. The site of autolytic activity was studied by allowing cell autolysis to proceed for very short periods (0 to 15 min) before addition of glutaraldehyde. Electron microscopy of ultrathin sections showed that the primary site of autolytic activity was the leading edge of the nascent cross wall. The base of the cross wall seemed more resistant than the tip. Evidence supporting the involvement of autolysin activity in continued wall extension and in cell separation as well as in the initiation of new sites of wall extension was obtained. In cells exposed for 10 min to chloramphenicol, wall dissolution was very much slower but occurred at the same cross wall site.
Relationship of Dipicolinic Acid Content in Spores of
Bacillus cereus
T to Ultraviolet and Gamma Radiation Resistance
Authors: Berg P. E. , Grecz N.
Published: January 2020

Spores of
Bacillus cereus
T lacking dipicolinic acid showed a statistically significant reduction in resistance to ultraviolet and γ radiation as compared with spores with high dipicolinic acid content.
Asymmetric Template Function of Microbial Deoxyribonucleic Acids: Transcription of Ribosomal and Soluble Ribonucleic Acids
Authors: Margulies Lola , Remeza Virgilija , Rudner Rivka
Published: January 2020

In
Bacillus subtilis
and
Escherichia coli
, 16 and 23
S
ribosomal ribonucleic acid (rRNA) hybridize exclusively with the heavy (H) strand of methylated albuminkieselguhr (MAK)-fractionated complementary deoxyribonucleic acid (DNA) strands. All the soluble RNA (4
S
RNA) in
B. subtilis
and 66 to 75% of the 4
S
RNA in
E. coli
also hybridize with the H strand. Interspecific hybridization shows that
E. coli
23
S
rRNA also binds selectively to the DNA H strand of
Salmonella typhimurium
. The hybridization peak for all three cellular RNA components is specifically located in the late-eluting region of the absorbance profile of the DNA H strand. The early-eluting region of the light (L) strand preferentially inhibits the hybridization between the peak region of the H strand and 23
S
rRNA. These regions are considered to represent the transcribing sequences and their complements for 23
S
rRNA in the separated H and L strands of DNA, respectively.
Inhibition of Carotenoid Hydroxylation in
Staphylococcus aureus
by Mixed-Function Oxidase Inhibitors
Authors: Hammond Ray K. , White David C.
Published: January 2020

Compounds known to be inhibitors of mixed-function oxidase systems inhibited the aerobic synthesis of hydroxylated carotenoids in
Staphylococcus aureus
U-71. Growth of the cells in the presence of 2-diethylaminoethyl-2,2-diphenyl valerate, 2,4-dichloro-6-phenylphenoxyethylamine, 2,4-dichloro-6-phenylphenoxyethyldiethylamine, and piperonyl butoxide reduced the levels of the rubixanthins found in stationary-phase cells by 75 to 97%. In cells grown with mevalonate-
2
-
14
C
, the turnover rate of phytoene was reduced and the turnover rate of phytofluenol was increased in the presence of these inhibitors. The ζ- and δ-carotenes, which turn over in the absence of the inhibitors, accumulated
14
C in the presence of the inhibitors. This suggested that a mixed-function oxidase was responsible for the aerobic hydroxylation of δ-carotene in
S. aureus
U-71.
Studies on the Pathway of Incorporation of 2-Aminopurine into the Deoxyribonucleic Acid of
Escherichia coli
Authors: Rogan Eleanor G. , Bessman Maurice J.
Published: January 2020

A pathway for the incorporation of 2-aminopurine into deoxyribonucleic acid (DNA) was studied in cell-free extracts of
Escherichia coli
. It was demonstrated that the free base can be converted to the deoxynucleoside, and that the deoxynucleotide can be phosphorylated to the di- and triphosphates and then incorporated into the DNA. From a consideration of the individual reactions in crude extracts, it is likely that the rate-limiting step in this pathway is the formation of the deoxynucleotide. Of especial interest is the observation that 2-aminopurine may be viewed as an analogue of either guanine or adenine, depending on which enzymatic step is being considered. On the one hand, it resembles guanine in that it is specifically converted from the mono- to the diphosphate by guanylate kinase and not by adenylate kinase. On the other hand, it replaces adenine rather than guanine in the DNA synthesized with purified DNA polymerases.
E. coli
DNA polymerase utilizes aminopurine deoxynucleoside triphosphate as a substrate for DNA synthesis much better than does purified phage T5-induced DNA polymerase and is also much less inhibited by this analogue than the T5 enzyme. These experiments in vitro correlate with known differential effects of 2-aminopurine on
E. coli
and phage in vivo.
Photoinhibition of Growth in
Acanthamoeba castellanii
Cultures
Authors: Dolphin Warren D.
Published: January 2020

Light from 350 to 680 nm at intensities up to 1.62 × 10
5
ergs per sec per cm
2
slowed exponential growth and lowered the maximum yield in axenic cultures of
Acanthamoeba castellanii
. Photoinhibition was a linear function of light intensity up to 1.25 × 10
5
ergs per sec per cm
2
. At higher intensities, growth was too slow to be measured accurately. A photochemical change occurring in the growth medium on irradiation was a function of light dosage and not intensity per se. Light in dosages which appreciably changed the growth-supporting properties of the medium exceeded the dosages received by exponentially growing cultures during irradiation. Consequently, photoinhibition of growth was attributed to a direct effect of light on the amoebae, not to photodegradation of the medium. The growth-supporting properties of irradiated media could be restored by the addition of yeast extract and Proteose peptone. The reduced growth rate in the light was not due to cyst formation or induction of multinuclearity. Light affected the amoebae either through absorption by intracellular pigment(s) or through binding to the amoebae of a photosensitizing compound in the medium.
Mechanism of
d
-Cycloserine Action: Transport Systems for
d
-Alanine,
d
-Cycloserine,
l
-Alanine, and Glycine
Authors: Wargel Robert J. , Shadur Craig A. , Neuhaus Francis C.
Published: January 2020

The accumulation of
d
-alanine,
l
-alanine, glycine, and
d
-cycloserine in
Escherichia coli
was found to be mediated by at least two transport systems. The systems for
d
-alanine and glycine are related, and are separate from that involved in the accumulation of
l
-alanine.
d
-Cycloserine appears to be primarily transported by the
d
-alanine-glycine system. The accumulation of
d
-alanine, glycine, and
d
-cycloserine was characterized by two line segments in the Lineweaver-Burk analysis, whereas the accumulation of
l
-alanine was characterized by a single line segment.
d
-Cycloserine was an effective inhibitor of glycine and
d
-alanine accumulation, and
l
-cycloserine was an effective inhibitor of
l
-alanine transport. The systems were further differentiated by effects of azide, enhancement under various growth conditions, and additional inhibitor studies. Since the primary access of
d
-cycloserine in
E. coli
is via the
d
-alanine-glycine system, glycine might be expected to be a better antagonist of
d
-cycloserine inhibition than
l
-alanine. Glycine and
d
-alanine at 10
−5
m
antagonized the effect of
d
-cycloserine in
E. coli
, whereas this concentration of
l
-alanine had no effect.
Mechanism of Polymyxin B Resistance in
Proteus mirabilis
Authors: Sud Inder Jit , Feingold David S.
Published: January 2020

The lipids from three types of organisms—a
Proteus mirabilis
wild type highly resistant to polymyxin B, a polymyxin B-sensitive mutant derived from the wild type, and the wild type grown in the presence of sulfadiazine resulting in phenotypic conversion to polymyxin B sensitivity—were examined to determine the nature of polymyxin B resistance. The phospholipid compositions were nearly identical; each organism contained similar small amounts of
N
-methyl phosphatidylethanolamine in addition to comparable quantities of phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin. the fatty acid compositions were similar in the exponential phase of growth; in the stationary phase, sulfadiazine markedly inhibited the synthesis of cyclopropane fatty acids. Liposomes prepared from the dried lipids of the three types of organisms were extensively and similarly disrupted by the polymyxin. These findings suggest that polymyxin B resistance in
P. mirabilis
is determined by the cell envelope which prevents access of the antibiotic to the susceptible lipid target sites.
Circular R-Factor Molecules Controlling Penicillinase Synthesis, Replicating in
Escherichia coli
Under Either Relaxed or Stringent Control
Authors: Kontomichalou Polyxeni , Mitani Michiko , Clowes Royston C.
Published: January 2020

Two infectious drug-resistance (R) factors, R28K and R6K, each conferring resistance to a number of penicillins by the synthesis of a penicillinase, were transferred to
Proteus mirabilis
PM1 and
Escherichia coli
RC85 host strains. Deoxyribonucleic acid (DNA) extracted from these strains was separated by density-gradient centrifugation and subjected to electron microscopy by use of a modification of the protein-monolayer diffusion technique. Analytical density-gradient centrifugation of the purified DNA from PM1 strains showed, in addition to the major peak at a density of 1.698 g/cm
3
characteristic of
Proteus
chromosomal DNA, a single satellite band at a density of 1.710 g/cm
3
[guanine plus cytosine (GC) base ratio 50%] for R28K and at 1.704 g/cm
3
(GC base ratio 45%) for R6K. Direct CsCl density-gradient centrifugation of crude lysates of the
E. coli
(R28K)
+
strain in the presence of ethidium bromide gave rise to a sedimentation profile with a single satellite peak containing covalently closed circular (CCC) DNA molecules with a mean contour length of 21.4 μm [44 × 10
6
atomic mass units (AMU)], although a minority was 13.6 μm in length. From the size of the major class, it was estimated that there were two to three copies of the R28K factor present as CCC molecules per chromosome at various phases of cellular growth. Similar studies of the
E. coli
(R6K)
+
lysates showed two satellite peaks; peak I contained mostly CCC molecules of contour length 12.8 μm (26 × 10
6
AMU), and peak II, intermediate to peak I and the chromosomal peak, contained CCC molecules of a similar size, together with about equal numbers of catenated molecules, mostly dimers consisting of two interlocked monomers of 12.8 μm. A smaller number (ca. 0.1%) of higher catenanes was also seen. The number of CCC copies of the R6K factor per chromosome present in peak I was calculated as 13 at logarithmic phase and 38 at stationary phase. In peak II, a constant ratio of about one catenated dimer per chromosome was found at all phases of growth. Penicillinase assays of cultures at different phases of growth showed a correlation between the estimated number of R-factor copies present as CCC molecules and the enzyme activity per cell for both R28K and R6K.
Metabolic Influences on Tyrosine Excretion in
Bacillus subtilis
Authors: Champney W. Scott , Jensen Roy A.
Published: January 2020

The biosynthetic pathway for tyrosine synthesis is regulated both by repression of enzyme synthesis and by feedback inhibition of enzyme activity in
Bacillus subtilis
. Nevertheless, wild-type cells produce significantly more tyrosine than is required for protein synthesis, and part of this is excreted into the medium. Alteration of nutritional and other environmental conditions of cultivation strongly influenced the amount of tyrosine excretion. The excretion of tyrosine by wild-type cells was compared with that of a regulatory mutant having a feedback-insensitive prephenate dehydrogenase. Tyrosine excretion varied directly with the in vitro activity of prephenate dehydrogenase and inversely with temperature in the two strains. The regulatory mutant excreted five times as much tyrosine as the wild type at all growth temperatures examined. The carbon source used for growth significantly influenced the level of tyrosine excretion. The specific activity of prephenate dehydrogenase was also affected by the carbon source. Incorporation studies with isotopic tyrosine and fluorometric determinations of tyrosine concentrations extractable in hot water were used to measure operationally the tyrosine pools in the mutant and wild-type strains. The effects of various environmental conditions on the synthesis and excretion of tyrosine led to the conclusion that metabolic controls governing end product contrations exist which are completely independent of regulation by feedback inhibition and repression.
Polyphasic Taxonomy of the Genus
Vibrio:
Polynucleotide Sequence Relationships Among Selected
Vibrio
Species
Authors: Citarella R. V. , Colwell R. R.
Published: January 2020

Polynucleotide relationships among selected
Vibrio
species were examined by means of deoxyribonucleic acid (DNA) reassociation reactions and chromatography on hydroxyapatite. Relative levels of intraspecific DNA duplex formation (
V. cholerae-V. cholerae
and
V. parahaemolyticus-V. parahaemolyticus
) were found to be high at 60 C (>80%), and only minimally reduced at 75 C. Interspecific DNA duplexes between
V. cholerae
DNA and that of the non-cholera vibrios also exhibited high relative levels of formation at 60 C (>80%) and, with one exception, were only slightly reduced at 75 C. The thermal stability of these duplexes formed at 60 or 75 C was virtually identical to that of homologous
V. cholerae
DNA duplexes. The degree of reassociation and the thermal stability of
V. cholerae
-non-cholera vibrio DNA duplexes suggests relatively little evolutionary divergence in these organisms. In all other interspecific DNA reassociation reactions, only low levels of DNA duplex formation were noted at 60 C (<25%), and these were drastically reduced (>50%) at 75 C. The degree of nucleotide sequence divergence indicated by these reactions suggests that these
Vibrio
species are not significantly related to
V. cholerae
or
V. parahaemolyticus
. Reassociation reactions between
V. cholerae
DNA and the DNA of
V. parahaemolyticus
indicated these species were not significantly related to each other.
Cytochemical Localization of Certain Phosphatases in
Escherichia coli
Authors: Wetzel Bruce K. , Spicer S. S. , Dvorak Harold F. , Heppel Leon A.
Published: January 2020

Cytochemical studies of
Escherichia coli
at the light and electron microscopic levels have revealed alkaline phosphatase, hexose monophosphatase, and cyclic phosphodiesterase reaction products in the periplasmic space and at the cell surface. In preparations for both light and electron microscopy, reaction product filled polar caplike enlargements of the periplasmic space, such as those described in plasmolyzed cells, indicating significant terminal concentrations of these enzymes; dense substance was often seen within these polar caps in morphological specimens. Staining of the bacterial surface was commonly encountered, but could represent artifactual accumulation of precipitate along the cell wall. Alkaline phosphatase was demonstrated with several substrates (ethanolamine phosphate, glycerophosphate,
p
-nitrophenylphosphate, and glucose-6-phosphate) over a wide
p
H range in a bacterial strain (C-90) known to be constitutive for this enzyme, whereas strains deficient in this enzyme (U-7, repressed K-37), showed no activity with these substrates. Hexose monophosphatase and cyclic phosphodiesterase activities were characterized by reaction-product deposition with specific substrates at acid or neutral, but not at alkaline,
p
H in strains of
E. coli
lacking alkaline phosphatase (U-7 and repressed K-37). Fixation in Formalin or the use of calcium as a capture reagent seemed to interfere with periplasmic staining in cells prepared for electron microscopy. Formalin fixation had little effect on biochemical assays of the phosphatase activity of intact cells in suspension, but partially reduced the activity evident in sonically treated extracts or in suspensions of dispersed cryostat sections. Glutaraldehyde treatment impaired enzyme activity more drastically.
Evidence for a Surface Protein Layer on the
Saccharomyces cerevisiae
Ascospore
Authors: Briley M. S. , Illingworth R. F. , Rose A. H. , Fisher D. J.
Published: January 2020

Electrophoretic measurements on
Saccharomyces cerevisiae
ascospores indicated the presence of a surface protein layer which can be removed by papain, chymotrypsin or 8
m
urea.
Accumulation of Streptomycin-Phosphate in Cultures of Streptomycin Producers Grown on a High-Phosphate Medium
Authors: Miller Ann L. , Walker James B.
Published: January 2020

A phosphorylated derivative of streptomycin accumulated in cultures of
Streptomyces griseus
ATCC 12475 and SC2376 grown on complex media containing an excess of inorganic phosphate (0.01
m
). This compound did not accumulate significantly in the absence of added inorganic phosphate. The phosphorylated derivative did not inhibit growth of
Bacillus subtilis
or support growth of a streptomycin-dependent strain of
Escherichia coli;
however, incubation of the derivative with alkaline phosphatase gave a compound which was active with both systems. In the phosphorylated derivative, phosphate is esterified with an —OH group of the streptidine moiety of streptomycin. It is suggested that the phosphoryl group is introduced during biosynthesis of the streptidine moiety of streptomycin or by the action of streptomycin kinase on preformed streptomycin (or both), and subsequent dephosphorylation by streptomycin-phosphate phosphatase is inhibited by high concentrations of inorganic phosphate. A column chromatographic procedure for separation of streptidine-phosphate, streptomycin-phosphate, and streptomycin is described.
Method for Isolation of Deoxyribonucleic Acid from Mycobacteria
Authors: Mizuguchi Yasuo , Tokunaga Tohru
Published: January 2020

A relatively gentle and efficient procedure for obtaining deoxyribonucleic acid from mycobacteria by the use of glycine and lysozyme is described.
Cardiolipin-Specific Phospholipase D of
Haemophilus parainfluenzae
II. Characteristics and Possible Significance
Authors: Ono Yoshie , White David C.
Published: January 2020

A phospholipase specific for cardiolipin (CL) was found in the membrane of
Haemophilus parainfluenzae
. The enzyme hydrolyzed CL to phosphatidic acid (PA) and phosphatidylglycerol (PG), indicating that it was a phospholipase D (an enzyme activity believed to be confined to higher plants). In addition to its substrate specificity, this enzyme was unusual in its requirement for Mg
2+
(
K
m
of 1.3 m
m
) for maximal activity and its inhibition by chelating agents, heavy metals, some detergents, and organic solvents. When inhibitors of phospholipase activity were added to the growth medium, CL accumulated and PG disappeared in the membrane, suggesting that the phospholipase D was active in vivo. The activity of phospholipase D in cell-free homogenates was greater than expected from earlier studies of CL metabolism and greater than the other phospholipase activities detected in the homogenate. The high activity of the CL-specific phospholipase D suggests there might be a very active degradation of CL to PG and PA and an active resynthesis of CL from the hydrolysis products.
Methylated Bases of
Bacillus megaterium
KM Nucleic Acids: Comparison with
Escherichia coli
Authors: Wachsman J. T. , Irwin V.
Published: January 2020

Parallel studies were performed with methionineless derivatives of
Escherichia coli
15 T
−
and
Bacillus megaterium
KM: T
−
. Methylated bases are present in the total cell ribonucleic acid (RNA) of
B. megaterium
. The level of RNA methylation in
E. coli
is about 60% greater than that in
B. megaterium
. Although
E. coli
deoxyribonucleic acid (DNA) was found to contain 0.12% 5-methylcytosine (5-MC) and 0.24% 6-methylaminopurine (6-MA), methylated bases were not detected in the DNA of
B. megaterium
. Assuming a molecular weight of 7 × 10
9
daltons for
B. megaterium
DNA, it was calculated that this organism could not contain more than one molecule of 5-MC or 6-MA per genome, and that possibly no methylated bases were present. Methylated bases were also not detected in the DNA of thymine-starved
B. megaterium
. Crude extracts of this organism possess RNA methylase activity but no detectable DNA methylase activity.
Requirement for Acetate and Glycine (or Serine) for Sporulation Without Growth of
Bacillus subtilis
Authors: Sugae Kin-Ichi , Freese Ernst
Published: January 2020

Cells of
Bacillus subtilis
sporulate when they are transferred, at any time of growth in nutrient sporulation medium, to a potassium-phosphate buffer containing slowly utilizable carbon sources such as
l
-aspartate, citrate,
l
-glutamate, or lactate. Transfer to buffer containing more rapidly utilizable carbon sources such as malate or glucose leads to sporulation only when the cells either had reached the end of growth or when the transfer medium also contains glycine. Acetate, which as a sole carbon source does not allow growth, also does not alone permit sporulation; however, the presence of both acetate (0.05
m
) and glycine or
l
-serine (0.01
m
) in the buffer medium allows sporulation if the cells are transferred to this medium after they have grown in the nutrient sporulation medium beyond the end of the exponential growth phase (T
0
). The development, required before transfer, does not seem to involve the end of a round of deoxyribonucleic acid duplication, as experiments with tryptophan-starved cells have indicated. Glycine or serine cannot be replaced by any of the known metabolites, which are partially derived from them. Amino acid analysis of nutrient sporulation medium showed that glycine (but not serine) is present at a concentration of 0.3 m
m
at the beginning of the developmental period, thus allowing, in combination with an acetyl-coenzyme A (CoA) precursor, sporulation but not growth. Acetyl-CoA is required not only for adenosine-triphosphate synthesis but also for some other reactions.
Kinetics of Allosteric Inhibition In Vivo: a Quantitative Analysis with Synchronous Cultures of
Blastocladiella emersonii
Authors: Smith David F. , Holmes Roger A.
Published: January 2020

Negative feedback control of the arginine biosynthetic pathway of
Blastocladiella emersonii
was observed in vivo by conducting kinetic radioisotope incorporation experiments. Transient responses of arginine precursor pools to perturbations in the medium end product concentration allowed a quantitative description of the negative feedback associated with pathway control, indicated that the
N
α
-acetyl-
l
-glutamate pool size was the controlled variable, and suggested that
N
α
-acetyl-
l
-glutamate and
l
-ornithine were the products of a transacetylation reaction in which
N
α
-acetyl-
l
-ornithine and glutamic acid were the reactants. The precursors to arginine biosynthesis were found to undergo two discrete disturbances in response to altering the exogenous arginine concentration only once. An increased supply of exogenous end product resulted in diminished radioactivity in the intracellular pools of arginine, ornithine, and acetyl-glutamate, but elevated the radioisotope content of the pool of
N
α
-acetyl-
l
-ornithine. Conversely, a lowered concentration of end product in the medium caused a rise in the radioisotope content of all the precursor pools except that of
N
α
-acetyl ornithine, in which the radioactivity fell. Examination of tracer distribution among the precursors in the absence of exogenous arginine showed the nonacetylated precursor pools to be about 30 times larger than those of the acetylated intermediates and placed upper limits on the pool sizes of two pathway members that were not isolated (
N
α
-acetyl-
l
-glutamic-γ-semialdehyde and
N
α
-acetyl-
l
-glutamic-γ-semiphosphate).
Active Transport of Manganese in Isolated Membranes of
Escherichia coli
Authors: Bhattacharyya Pinakilal
Published: January 2020

Accumulation of manganese was measured in subcellular membrane vesicles isolated from
Escherichia coli
. Accumulation of
54
Mn by vesicles in 0.5
m
sucrose is stimulated by glucose and
d
-lactate and is inhibited by metabolic poisons such as dinitrophenol,
m
-chlorophenyl carbonylcyanide hydrazone, valinomycin, and nigericin. Manganese uptake by vesicles requires 10 m
m
calcium, which is not required for uptake of manganese by intact cells. The calcium requirement is specific and cannot be replaced by magnesium, sodium, or potassium. Strontium can replace calcium but is somewhat less effective than calcium. The uptake of manganese is via a manganese-specific system which shows saturation kinetics with manganese with a
K
m
of 8 × 10
−6
m
and a
V
max
of 4 nmoles per min per g (wet weight) at 25 C. Magnesium and calcium do not compete for uptake. The accumulated manganese can be released from the vesicles by lipid active agents such as toluene, and can be exchanged for external manganese.
Separation and Localization of Cell Wall Layers of a Gram-Negative Bacterium
Authors: Forsberg C. W. , Costerton J. W. , MacLeod Robert A.
Published: January 2020

The cell envelope of a marine pseudomonad as seen in thin section by electron microscopy has the double-membrane structure typical of other gram-negative bacteria. Cells washed with a solution containing Na
+
, K
+
, and Mg
++
at their concentrations in the growth medium, when suspended briefly in 0.5
m
sucrose, lost 13% of their hexosamine in a form nonsedimentable by centrifugation at 73,000 ×
g
. Since the resulting cells in thin section appeared unchanged, it was concluded that the material released was derived from a nonstaining, loosely bound outer layer. This same layer could be removed from the cells by washing with 0.5
m
NaCl. A second nonsedimentable fraction was released after successive suspension of the cells in 0.5
m
sucrose. Since this material was released only when the outer double-track structure had broken, it was concluded that it arose from a layer immediately underlying the latter layer. The three layers differed in their content of hexosamine and protein. None of the layers released contained muramic or diaminopimelic acid. The cell form remaining was rod shaped and appeared in thin section to be bounded only by its cytoplasmic membrane. This form contained all the muramic and diaminopimelic acid in the cell. Treatment with lysozyme released the muramic and diaminopimelic acid and converted the rod form to a protoplast, indicating that in the rod form (mureinoplast) a thin layer of peptidoglycan is located on the outside surface of the cytoplasmic membrane. Thus, five separate layers have been detected in the cell envelope of this marine pseudomonad.
Thymine Starvation and Single-Strand Breaks in Chromosomal Deoxyribonucleic acid of
Escherichia coli
Authors: Walker James R.
Published: January 2020

Single-strand breaks, as measured by the McGrath and Williams procedure, occur in chromosomal deoxyribonucleic acid of
Escherichia coli
cells during thymine starvation.
Catabolism of Fructose and Mannitol in
Clostridium thermocellum:
Presence of Phosphoenolpyruvate: Fructose Phosphotransferase, Fructose l-Phosphate Kinase, Phosphoenolpyruvate: Mannitol Phosphotransferase, and Mannitol l-Phosphate Dehydrogenase in Cell Extracts
Authors: Patni N. J. , Alexander James K.
Published: January 2020

Fructose and mannitol are fermented by
Clostridium thermocellum
in a medium containing salts and 0.5% yeast extract. The initial reaction in the catabolism of fructose was found to be the formation of fructose l-phosphate by phosphoenolpyruvate (PEP):fructose phosphotransferase which resembles the Kundig-Roseman phosphotransferase system. The phosphorylation of fructose l-phosphate to form fructose-1, 6-diphosphate is catalyzed by fructose l-phosphate kinase. Fructose-1, 6-diphosphate can be further metabolized by the Embden-Meyerhof pathway. The formation of both PEP:fructose phosphotransferase and fructose l-phosphate kinase is induced by growth in fructose medium. Mannitol catabolism was found to proceed by the phosphorylation of mannitol by PEP:mannitol phosphotransferase to form mannitol l-phosphate. Mannitol l-phosphate is converted to fructose 6-phosphate by a nicotinamide adenine dinucleotide-specific mannitol l-phosphate dehydrogenase. The fructose 6-phosphate formed in the reaction can enter the glycolytic scheme. The formation of both PEP:mannitol phosphotransferase and mannitol l-phosphate dehydrogenase is induced by growth in mannitol medium. Evidence is presented for the induction by mannitol of PEP:mannitol phosphotransferase and mannitol l-phosphate dehydrogenase in suspensions of fructose-grown cells.
Mutants of
Salmonella typhimurium
Able to Utilize
d
-Histidine as a Source of
l
-Histidine
Authors: Krajewska-Grynkiewicz Krystyna , Walczak W. , Kłopotowski T.
Published: January 2020

Secondary mutants able to utilize
d
-histidine,
dhu
, were isolated in histidine auxotrophs of
Salmonella typhimurium
. Mutations of one class (
dhuA
) are closely linked with the
hisP
locus which codes for a component of histidine permease. The specific activity of
l
-histidine permeation was estimated as increased two- to seven-fold in
dhuA
mutants. The
dhuB
mutants which have not been mapped also had elevated specific activity of
l
-histidine permeation. The uptake of
d
-histidine, barely detectable in the parental strains, was prominent in
dhuA
mutants and showed an apparent Michaelis constant about 1,000-fold higher than that observed with
l
-histidine. No change was detected in the kinetics of
l
-histidine permeation.
d
- and
l
-histidine competed in the uptake process. Tertiary mutants which lost the ability to grow on
d
-histidine were isolated by ampicillin counter-selection in
dhuA his
−
strains. All of them mapped in the
dhuA hisP
region. Most of them had all known properties of
hisP
mutants. It is inferred from these data that the
dhuA
mutations increase synthesis of components critical to
d
- and
l
-histidine permeation.
Ultrastructural Changes Associated with Activation and Germination of
Bacillus cereus
T Spores
Authors: Hashimoto Tadayo , Conti S. F.
Published: January 2020

The ultrastructural changes occurring during defined stages of the transition of dormant
Bacillus cereus
T spores into heat-sensitive forms were investigated. The coat of the heat-activated spores displayed conspicuous striations across its middle layer. Electron microscopy of thin sections of heat-activated spores revealed the presence in the spore of a layer consisting of hexagonally oriented subunits. It was demonstrated that the subcoat region, but not the cortex, disappears rapidly during germination of
B. cereus
T spores. The fibrous structures apparently associated with the spore coat remain virtually unchanged during the entire course of activation and germination.
Fine Structure and Isolation of the Hook-Basal Body Complex of Flagella from
Escherichia coli
and
Bacillus subtilis
Authors: DePamphilis M. L. , Adler Julius
Published: January 2020

The hook-basal body complex comprising the basal end of purified intact flagella from
Escherichia coli
and
Bacillus subtilis
was studied in detail with an electron microscope. The
E. coli
hook can be described as having five or six concentric helical coils. The basal body from
E. coli
is 27 nm in length and consists of four rings, 22.5 nm in diameter, arranged in two pairs and mounted on a rod. The top pair of rings is connected near their periphery, resembling a closed cylinder. In
B. subtilis
the basal body looks like that from
E. coli
, except that the top pair of rings is missing. Hook-basal body complexes from both organisms could be isolated by dissociating the filaments with either urea or acid. Based on our results, two types of basal body structures are proposed, as exemplified by
E. coli
and
B. subtilis
, which directly reflect the structure of the gram-negative and gram-positive cell envelopes.
Carbon Dioxide Requirement of Various Species of Rumen Bacteria
Authors: Dehority B. A.
Published: January 2020

The carbon dioxide requirement of 32 strains of rumen bacteria, representing 11 different species, was studied in detail. Increasing concentrations of CO
2
were added as NaHCO
3
to a specially prepared CO
2
-free medium which was tubed and inoculated under nitrogen. Prior depletion of CO
2
in the inoculum was found to affect the level of requirement; however, the complexity and buffering capacity of the medium did not appear to be involved. An absolute requirement for CO
2
was observed for eight strains of
Bacteroides ruminicola
, three strains of
Bacteroides succinogenes
, four strains of
Ruminococcus flavefaciens
, two strains of
Lachnospira multiparus
, one strain of
Succinimonas amylolytica
, and two strains of
Butyrivibrio fibrisolvens
. Inconsistent growth responses were obtained in CO
2
-free media with one strain each of
B. fibrisolvens, Ruminococcus albus
, and
Selenomonas ruminantium
. Growth of six additional strains of
B. fibrisolvens
, and single strains of
Eubacterium ruminantium
and
Succinivibrio dextrinosolvens
was markedly increased or stimulated by increasing concentrations of CO
2
.
Peptostreptococcus elsdenii
B159 was the only organism tested which appeared to have no requirement, either absolute or partial, for CO
2
. Higher concentrations of CO
2
were required for the initiation of growth, as well as for optimal growth, by those species which produce succinic acid as one of their primary end products.
Formation of Nitrate from 3-Nitropropionate by
Aspergillus flavus
Authors: Molina J. A. E. , Alexander M.
Published: January 2020

Extracts of the hyphae of a nitrifying strain of
Aspergillus flavus
formed nitrite and nitrate from 3-nitropropionate. Nicotinamide adenine dinucleotide phosphate and nicotinamide adenine dinucleotide enhanced the production of nitrate but not nitrite, whereas cysteine and diethyldithiocarbamate increased nitrite but diminished nitrate synthesis. Quinacrine reduced the extent of conversion of the nitro compound to nitrite and nitrate, but only the inhibition of nitrite formation was completely reversed by flavine coenzymes. Molecular oxygen was essential for this part of the nitrification sequence. 3-Chloropropionate stimulated the oxidation of nitrite by hyphae or enzyme preparations. Although the fungus contained a noncytochrome-linked nitrite-oxidizing enzyme, partially purified preparations free of this enzyme formed both nitrite and nitrate from 3-nitropropionate. Possible mechanisms of this latter stage of heterotrophic nitrification are discussed.
Effects of
N
-Hydroxyurethan on Viability and Metabolism of
Escherichia coli
Authors: Mullinix Kathleen P. , Rosenkranz Herbert S.
Published: January 2020

Exposure of growing cells to low levels of
N
-hydroxyurethan (approximately 0.05
m
) resulted in loss of colony-forming ability. This was accompanied by degradation of cellular deoxyribonucleic acid. When the concentration of
N
-hydroxyurethan was increased to 0.2
m
, bacteriostasis was the primary manifestation. The lethal action of the drug was prevented by contreatment with chloramphenicol or azauracil or by uracil-deprivation of a bacterial strain requiring this pyrimidine for growth.
Iron Requirements and Aluminum Sensitivity of an Hydroxamic Acid-Requiring Strain of
Bacillus megaterium
Authors: Davis W. B. , McCauley M. J. , Byers B. R.
Published: January 2020

Bacillus megaterium
strain ATCC 19213 secretes a ferric-chelating secondary hydroxamic acid, whereas a mutant (strain SK11) derived from it cannot produce a hydroxamate. Strain SK11 could be cultivated in a sucrose-mineral salts medium (treated with Chelex 100 to reduce trace metals) in the absence of added hydroxamate, if the inoculum was high. The lowest iron supplements necessary for maximal growth of both strains were equivalent (0.01 to 0.04 μg of iron per ml). Addition of either aluminum (0.5 μg/ml) or chromium (0.1 μg/ml) to the medium prevented full growth of strain SK11 at the minimal iron concentration, although elevated iron (1 μg/ml) reversed this inhibition. The iron-free secondary hydroxamate, Desferal, also abolished aluminum and chromium inhibition of strain SK11, producing maximal population densities at the low iron concentration. Growth of the hydroxamate-producing strain 19213 was not altered significantly by the aluminum or chromium levels which inhibited strain SK11. However, strain 19213 responded to these metals by increasing its secretion of a secondary hydroxamate. It was concluded that aluminum and chromium interfered with iron incorporation, either directly or by formation of nonutilizable aggregates with iron. The secondary hydroxamates may have overcome this interference by solubilization of iron for delivery to a single uptake process, or the ferric-hydroxamate chelate may enter the cell by an alternate route.
Biosynthesis of T1 Antigen in
Salmonella:
Origin of
d
-Galactofuranose and
d
-Ribofuranose Residues
Authors: Sarvas Matti , Nikaido Hiroshi
Published: January 2020

The “T1 side chain” portion of cell wall lipopolysaccharide from T1 strains of
Salmonella
contains
d
-galactofuranose and
d
-ribofuranose residues. Isotope labeling studies, using intact cells of mutants each blocked at either of the two different steps of
d
-galactose metabolism (uridine diphosphate-glucose 4-epimerase and galactose-1-P uridylyl transferase) or at phosphoglucoisomerase, led to the following conclusions. (i)
d
-Galactofuranose residues are synthesized from
d
-galactopyranose or its derivatives, rather than by a direct conversion from other hexopyranoses or their derivatives. (ii) The pyranose-to-furanose conversion does not appear to take place at the level of the free
d
-galactose or
d
-galactose 1-phosphate. This result suggests that the conversion may occur at the stage of uridine diphosphate-
d
-galactose. (iii) In a mutant lacking phosphoglucoisomerase,
d
-ribofuranose residues in T1 side chains contained
14
C derived from exogenous
d
-fructose-
U
-
14
C
, but little
3
H from exogenous
d
-glucose-
1
-
3
H
. Thus, no evidence was found for a direct pathway of aldohexose-to-ribose conversion involving a loss of one of the carbons in the C2-C6 moiety of aldohexoses. This suggests, but does not prove, that the T1 ribofuranose residues are synthesized by conventional mechanisms involving hexose monophosphate shunt and transketolase-transaldolase reactions.
Respiratory Mechanisms in the
Flexibacteriaceae:
Terminal Oxidase Systems of
Saprospira grandis
and
Vitreoscilla
Species
Authors: Dietrich William E. , Biggins John
Published: January 2020

Particles from both
Saprospira grandis
and
Vitreoscilla
species, obtained by high-pressure extrusion and sonic treatment, respectively, actively catalyze the oxidation of reduced nicotinamide adenine dinucleotide (NADH) and succinate with O
2
. These activities are inhibited by cyanide but not by antimycin;
Saprospira
is also amytal- and rotenone-insensitive.
Vitreoscilla
preparations were unable to oxidize mammalian ferrocytochrome
c
and reduced tetramethyl-
p
-phenylenediamine, whereas the
Saprospira
preparations did so actively. Low-temperature (77 K) difference spectroscopy of
Vitreoscilla
cells and particles indicates the presence of three maxima in the cytochrome alpha-region at 554, 558, and 562 nm. All three cytochromes are active in NADH and succinate oxidation, but none is ascorbate reducible. Cytochrome
o
is the only CO-binding pigment present and is probably the terminal oxidase; it has properties similar to the cytochrome
o
isolated in solubilized form from this organism.
Saprospira
cells and membranes exhibit four cytochrome absorption bands whose maxima are at 550, 554, 558, and 603 nm at 77 K. The latter component has not been noted previously. NADH and succinate reduce all four cytochromes, but ascorbate reduces only the 550- and 603-nm pigments. CO spectra indicate the presence of cytochrome
a,a
3
which is probably the oxidase. A second CO-binding pigment is present which is not a peroxidase but may be a cytochrome.
Activation of the C
2
to C
19
Monocarboxylic Acids by
Pseudomonas
Authors: Trust T. J. , Millis Nancy F.
Published: January 2020

Cell extracts of pseudomonads grown on hexadecanoic acid contained C
11
to C
19
acyl thiokinase, C
4
to C
14
acyl thiokinase, C
2
to C
6
acyl thiokinase, acetyl thiokinase, and acetokinase.
Cell Wall Composition in
Corynebacterium bovis
and Some Other Corynebacteria
Authors: Cummins C. S.
Published: January 2020

The cell wall compositions of two strains of
Corynebacterium bovis
were found to differ: one contained lysine, rhamnose, mannose, and glucose, the other
meso
-α, ε, diaminopimelic acid (DAP), arabinose, galactose, and mannose. The walls of a strain of
C. nephridii
were characterized by
l
-DAP and galactose. Those of a strain of
C. paurometabolum
and of two strains of “lipophilic diphtheroids” contained
meso
-DAP, arabinose, galactose, and mannose as did walls of a reference strain of
C. xerosis
. The results are discussed in relation to the taxonomy of the organisms examined.
Genetic Analysis of Diaminopimelic Acid- and Lysine-Requiring Mutants of
Escherichia coli
Authors: Bukhari Ahmad I. , Taylor Austin L.
Published: January 2020

Several diaminopimelic acid (DAP)- and lysine-requiring mutants of
Escherichia coli
were isolated and studied by genetic, physiological, and biochemical means. The genes concerned with DAP-lysine synthesis map at several different sites on the
E. coli
chromosome and, therefore, do not constitute a single operon. Three separate loci affecting DAP synthesis are located in the 0 to 2.5 min region of the genetic map. The order of the loci in this region is
thr-dapB-pyrA-ara-leu-pan-dapC-tonA-dapD
. Two additional DAP genes map in the region between min 47 and 48, with the gene order being
gua-dapA-dapE-ctr
. The
lys
locus at min 55 determines the synthesis of the enzyme DAP decarboxylase, which catalyzes the conversion of DAP into lysine. The order of the genes in this region is
serA-lysA-thyA
.
Mechanism of Resistance to Antibiotic Synergism in Enterococci
Authors: Zimmermann Robert A. , Moellering Robert C. , Weinberg Arnold N.
Published: January 2020

Enterococci exhibit two types of resistance to streptomycin. Moderately high-level resistance is observed in most naturally occurring strains and can be overcome by simultaneous exposure to penicillin. In addition, very high-level resistance is found in those strains against which penicillin plus streptomycin fail to produce synergism in vitro. To study the mechanism of streptomycin resistance in enterococci, ribosomes from a wild-type strain and from a highly streptomycin-resistant mutant were isolated, characterized, and studied in an in vitro amino acid incorporation system. The ribosomes from the organism with moderately high-level streptomycin resistance were sensitive to streptomycin in vitro, suggesting that this type of resistance is caused by failure of streptomycin to reach the ribosomes. Very high-level resistance (and lack of penicillin-streptomycin synergism), on the other hand, appears to be due to ribosomally mediated streptomycin resistance.
Mechanism of Conversion of the Salmonella O Antigen by Bacteriophage ε34
Authors: Wright Andrew
Published: January 2020

The structural determinants for antigen 34 in the E group salmonella are glucosyl substituents on the galactosyl units of the O antigen which has a mannosylrhamnosylgalactose repeating sequence. The temperate bacteriophage ε34brings about the production of antigen 34. It has been shown here that glucose is transferred from uridine diphosphate glucose to the O antigen via a glucosyl-lipid intermediate in a two-step reaction. Glucose is linked through carbon 1 to the lipid by a phosphodiester bridge, the glucosyl bond having the β-anomeric configuration. The lipid is a C55-polyisoprenoid alcohol, each isoprene unit having one double bond. It is the same lipid which is involved in the synthesis of the O antigen repeating sequence.
Role of Lipopolysaccharides in Antibiotic Resistance and Bacteriophage Adsorption of
Escherichia coli
K-12
Authors: Tamaki Shigeo , Sato Tomoyasu , Matsuhashi Michio
Published: January 2020

Novobiocin-supersensitive (NS) mutants which could not grow on plates containing 40 μg or less of novobiocin per ml were isolated from
Escherichia coli
strain JE1011 (derived from
E. coli
K-12). Most of these NS mutants were found to have incomplete lipopolysaccharides (LPS), and they lack phosphate diester bridges in their backbone structure, with or without total loss of heptose, to which the phosphate diester is linked, and consequently lack external outer-core oligosaccharides. The phosphate diester bridges in the LPS backbone are apparently very important in forming a cell surface structure resistant to the penetration of antibiotics such as novobiocin, spiramycin, and actinomycin D. NS mutants, with incomplete LPS, lacking phosphates in their backbone structure were found to be resistant to phage T4, and those which also lacked heptose were resistant to phages T4 and T7. In contrast to the generally accepted idea that resistances to phages T3, T4, and T7 are linked genetically, no NS mutant was found to be resistant to T3. The possible structures of the receptors for T4 and T7 are discussed. The positions of novobiocin-supersensitive genes on the chromosome of several of the NS mutants defective in LPS were mapped. The genes were designated
lpcA
(between
ara
and
lac
) and
lpcB
(between 55 min and 60 min). The latter seemed to be a group of several related genes.