bluuebunny/crossref_metadata_2025 huggingface dataset:
Construction and Properties of
Escherichia coli
Strains Exhibiting α-Complementation of β-Galactosidase Fragments In Vivo
Authors: Zamenhof Patrice J. , Villarejo Merna
Published: January 2020

In vivo α-complementation of β-galactosidase was demonstrated in 16 Z gene terminator (nonsense) mutant strains of
Escherichia coli
upon introduction of the episome F′M15 which specifies production of a mutant Z gene polypeptide containing a small deletion in the N-terminal region of the enzyme monomer. Genetic and biochemical analyses of the merodiploids showed that restoration of enzyme activity was due to their terminator/F′M15 genetic constitution resulting in the production of two enzymatically inactive polypeptides which associate in vivo to reconstitute active, stable β-galactosidase. The prematurely terminated polypeptide fragments known to be rapidly degraded in haploid cells were shown by phenotypic and biochemical studies to be stabilized (i.e., protected) in merodiploids by formation of complemented enzyme complexes with the M15 protein. Phenotypic properties of complementing diploids are described and are discussed in relation to in vitro determination of β-galactosidase activity.
cis
-Terpin Hydrate Metabolism by a Brevibacterium: Patterns of Enzyme Induction, and Accumulation of α-Terpineol in Growth Media
Authors: Baum Robert H. , Marr Eleanor K.
Published: January 2020

A brevibacterium, strain TH-4, previously isolated by aerobic enrichment on the monocyclic monoterpenoid
cis
-terpin hydrate as a sole carbon and energy source, was found to grow on α-terpineol and on a number of common sugars and organic acids. Oxidation of these terpenoids was shown to occur via an induced enzyme system, as measured manometrically by oxygen uptake and prevention of protein synthesis with chloramphenicol or puromycin. Oxidation of terpin hydrate by cell suspensions appeared to be coincidentally induced by growth on α-terpineol, and oxidation of α-terpineol similarly appeared to be induced by growth on terpin hydrate. Culture fluids in which the TH-4 organism was grown at the expense of
cis
-terpin hydrate were found to contain (−)-α-terpineol in combined butanol-ether extracts. The isolated compound was shown to be chromatographically and spectrophotometrically identical to an authentic sample of α-terpineol. The stereospecificity of an enzymatic dehydration of terpin hydrate to α-terpineol is considered.
Bacteriolytic Enzymes Produced by
Myxococcus xanthus
Authors: Sudo Sara , Dworkin Martin
Published: January 2020

The bacteriolytic activities in the culture fluid of
Myxococcus xanthus
were purified and separated into six active fractions by the use of Bio-Gel CM-2 and Bio-Gel P-60. These fractions were identified as: (i) an amidase, (ii) a glucosaminidase, (iii) a glucosaminidase and an amidase, (iv) a protease with probable amidase activity, (v) another protease with probable amidase activity, and (vi) a peptidase active on both
d
-alanyl-diaminopimelate and
d
-alanyl-lysine peptide bonds. On one occasion, another amidase was eluted from Bio-Gel CM. Preliminary studies on some characteristics of the enzymes and their production during growth are reported.
Deoxyribonucleic Acid Base Sequence Homologies of Some Budding and Prosthecate Bacteria
Authors: Moore Richard L. , Hirsch Peter
Published: January 2020

The genetic relatedness of a number of budding and prosthecate bacteria was determined by deoxyribonucleic acid (DNA) homology experiments of the direct binding type. Strains of
Hyphomicrobium
sp. isolated from aquatic habitats were found to have relatedness values ranging from 9 to 70% with strain “EA-617,” a subculture of the
Hyphomicrobium
isolated by Mevius from river water. Strains obtained from soil enrichments had lower values with EA-617, ranging from 3 to 5%. Very little or no homology was detected between the amino acid-utilizing strain
Hyphomicrobium neptunium
and other
Hyphomicrobium
strains, although significant homology was observed with the two
Hyphomonas
strains examined. No homology could be detected between prosthecate bacteria of the genera
Rhodomicrobium, Prosthecomicrobium, Ancalomicrobium
, or
Caulobacter
, and
Hyphomicrobium
strain EA-617 or
H. neptunium
LE-670. The grouping of
Hyphomicrobium
strains by their relatedness values agrees well with a grouping according to the base composition of their DNA species. It is concluded that bacteria possessing cellular extensions represent a widely diverse group of organisms.
Studies on
Escherichia coli
Enzymes Involved in the Synthesis of Uridine Diphosphate-
N
-Acetyl-Muramyl-Pentapeptide
Authors: Lugtenberg E. J. J.
Published: January 2020

The specific activities of
l
-alanine:
d
-alanine racemase,
d
-alanine:
d
-alanine ligase, and the
l
-alanine,
d
-glutamic acid,
meso
-diaminopimelic acid, and
d
-alanyl-
d
-alanine adding enzymes were followed during growth of
Escherichia coli
. The specific activities were nearly independent of the growth phase.
d
-Alanine:
d
-alanine ligase was inhibited by
d
-alanyl-
d
-alanine,
d
-cycloserine, glycine, and glycyl-glycine.
l
-Alanine:
d
-alanine racemase was found to be sensitive to
d
-cycloserine, glycine, and glycyl-glycine. The
l
-alanine adding enzyme was inhibited by glycine and glycyl-glycine.
Influence of Temperature on the Biosynthesis of Iron Transport Compounds by
Salmonella typhimurium
Authors: Garibaldi J. A.
Published: January 2020

The biosynthesis of phenolate iron transport compounds by
Salmonella typhimurium
Tm-1 is temperature-sensitive. As the temperature of incubation is raised from 31.0 to 36.9 C, the organism excretes less iron transport compound into the medium. The organism in unable to grow at 40.3 C on a 1% succinatesalts medium unless supplemented with such iron transport compounds. The iron requirement for maximum cell yields on this medium is 0.10 μg/ml. The biosynthesis of phenolate iron transport compounds is suppressed at iron concentrations greater than 3.0 μg/ml.
Effect of Growth Conditions on Morphology of
Hydrogenomonas facilis
and on Yield of a Phospholipoprotein
Authors: Heptinstall John , Rittenhouse Harry G. , McFadden Bruce A. , Shumway Lewis K.
Published: January 2020

Hydrogenomonas facilis
grown heterotrophically on fructose with very low aeration eventually ceased to divide and produced elongated forms. Short forms were obtained from fructose-grown long forms by increasing the availability of oxygen to the organisms. A phospholipoprotein, the protein moiety of which is known to be present in the cell envelope, precipitated upon lowering the ionic strength of extracts from cells in the earlier stages of elongation (i.e., in the middle and late log phase of growth). The maximal yield of the protein moiety of the phospholipoprotein precipitate (i.e., grams of protein/grams of soluble protein × 100) was 2%. Poly-β-hydroxybutyric acid accumulated as growth on fructose progressed, the accumulation being more marked with lower aeration.
Influence of Magnesium and Manganese on Some Biological and Physical Properties of Tetracycline
Authors: Sompolinsky David , Samra Zemira
Published: January 2020

Accumulation of
3
H-tetracycline in nonproliferating cells of susceptible and resistant strains of
Escherichia coli
and
Staphylococcus aureus
in tris(hydroxymethyl)aminomethane (Tris) buffer (10 m
m
,
p
H 7.5) was significantly decreased in the presence of 5 to 40 m
m
MgCl
2
and increased in the presence of 5 to 10 m
m
MnCl
2
. When the bacteria first accumulated
3
H-tetracycline in plain Tris·HCl, and the metal salts were thereafter added, a prompt decrease or increase in radioactivity of the cells was observed after the addition of Mg
2+
or Mn
2+
, respectively. In phosphate buffer (10 m
m
,
p
H 7.5), the effect of Mg
2+
was delayed. Three minutes after addition of
3
H-tetracycline, uptake was as in the control cell suspension, but thereafter it dropped rapidly. When
3
H-tetracycline was incubated with Mg
2+
before addition to the bacterial suspension, uptake was scarcely measurable. The addition of Mg
2+
to growing cultures of
S. aureus
and
E. coli
caused a marked decrease in susceptibility; in contrast, no increase in susceptibility could be demonstrated when Mn
2+
was added. It was also demonstrated that Mg
2+
and Mn
2+
had distinct influences on the absorption spectrum, the optical rotatory dispersion, the circular dichroism, and the lipid solubility of tetracycline.
Regulation of Nitrate Reductase in
Neurospora crassa
: Stability In Vivo
Authors: Subramanian K. N. , Sorger G. J.
Published: January 2020

Nicotinamide adenine dinucleotide phosphate, reduced form (NADPH)-nitrate reductase and its related enzyme activities, NADPH-cytochrome
c
reductase and reduced benzyl viologen-nitrate reductase, are all induced following the transfer of ammonia-grown wild-type
Neurospora
mycelia to nitrate medium. After nitrate reductase is induced to the maximal level, the addition of an ammonium salt to, or the removal of nitrate from, the cultures results in a rapid inactivation of nitrate reductase and its two partial component activities. This rapid inactivation is slowed down by the protein synthesis inhibitor, cycloheximide. Experiments on the mixing of extracts in vitro rule out the presence of an inhibitor of nitrate reductase in free form in extracts containing inactivated nitrate reductase. Ammonia does not inhibit the uptake of nitrate by the mycelia. Inactivation of nitrate reductase in vivo by ammonia depends on the concentration of the ammonium salt and is not reversed by increasing the nitrate concentration of the medium. The nitrate-inducible NADPH-cytochrome
c
reductase activity and reduced benzyl viologen-nitrate reductase activity respectively of the nitrate-nonutilizing mutants
nit-1
and
nit-3
are not inactivated in vivo by the addition of an ammonium salt or the withdrawal of nitrate. This finding suggests that the integrity of the nitrate reductase complex is required for the in vivo inactivation of nitrate reductase and its associated activities.
Control of Nucleotide Metabolism and Ribosomal Ribonucleic Acid Synthesis During Nitrogen Starvation of
Escherichia coli
Authors: Irr Joseph D.
Published: January 2020

Ribosomal ribonucleic acid (RNA) synthesis and ribonucleoside triphosphate metabolism were studied in cultures of
Escherichia coli
subjected to starvation for inorganic nitrogen. In a strain that was under stringent control, a 50-fold reduction in the formation of both 16
S
and 23
S
RNA was accompanied by a severe restriction on nucleotide biosynthesis. These inhibitions were relieved in part by incubating the starved cells with amino acids. This result suggests that regulation by the functional RNA control (RC) gene is involved in the effect. This suggestion was confirmed by showing that the effector of the stringent response, guanosine-5′-diphosphate-2′- or 3′-diphosphate (
pp
G
pp
), accumulated at the onset of starvation and disappeared immediately when the amino acids were added. Ribosomal RNA synthesis was severely restricted and the same nucleotide,
pp
G
pp
, accumulated at the onset of nitrogen starvation of a relaxed mutant too. These findings suggest that a control mechanism other than the one provided by the functional
rel
gene might operate to regulate RNA synthesis and that this mechanism is expressed through the synthesis of
pp
G
pp
.
Metabolism of Nicotinamide Adenine Dinucleotide in Human and Bovine Strains of
Mycobacterium tuberculosis
Authors: Kasârov Luka B. , Moat Albert G.
Published: January 2020

A marked difference was found to exist between the nicotinamide adenine dinucleotide (NAD) glycohydrolase activity of human strains of
Mycobacterium tuberculosis
as compared with bovine strains. Human strains had from 6- to 20-fold higher NAD glycohydrolase activity than bovine strains. This finding explains the accumulation of free nicotinic acid in the culture medium by human strains and not by bovine strains. The biosynthetic intermediates nicotinic acid mononucleotide and deamido-NAD were not degraded by either human or bovine strains of
M. tuberculosis;
hence these nucleotides do not represent a source of the nicotinic acid accumulated by the human strains.
Fructose-1,6-Diphosphate-Dependent Lactate Dehydrogenase from a Cariogenic Streptococcus: Purification and Regulatory Properties
Authors: Brown Albert T. , Wittenberger Charles L.
Published: January 2020

The lactate dehydrogenase (LDH) from
Streptococcus mutans
NCTC 10449 is under stringent metabolic control. The partially purified enzyme was specifically activated by high concentrations of fructose-1,6-diphosphate (FDP) and was inhibited by adenosine triphosphate. There appeared to be at least two binding sites for the activator which interacted in a cooperative manner. The interaction between the FDP sites was independent of the
p
H of the assay system, although the relative affinity of the enzyme for the activator was influenced by
p
H. There also appeared to be at least two pyruvate binding sites on the
S. mutans
LDH with some cooperative interaction between them, and the interaction between these sites was also independent of the hydrogen ion concentration. Two pyruvate analogues had different effects on the interaction of pyruvate with the LDH. One of the analogues, α-ketobutyrate, stimulated enzyme activity at limiting pyruvate concentrations, but had no significant effect at saturating concentrations of the substrate. The net effect of α-ketobutyrate was to shift the pyruvate saturation curve from sigmoidal to hyperbolic and to decrease the Hill coefficient from about 2.0 to 1.0. The other pyruvate analogue, oxamate, inhibited enzyme activity at all pyruvate concentrations but had no effect on the sigmoidal nature of the pyruvate saturation curve or on the apparent kinetic order of the reaction with respect to substrate. These results suggested that there may be two types of pyruvate binding sites on the LDH from
S. mutans
. Other kinetic properties of the
S. mutans
NCTC 10449 enzyme were studied and compared with those exhibited by the LDH from several other strains of the organism.
Simple and Reliable Method for Replica Plating
Neurospora crassa
Authors: Littlewood R. K. , Munkres K. D.
Published: January 2020

The details of a simple method for replica plating
Neurospora crassa
are described. The procedure has proved to be highly reliable for replica plating of colonies arising from either ascospores or conidia.
Effects of Molybdate, Tungstate, and Selenium Compounds on Formate Dehydrogenase and Other Enzyme Systems in
Escherichia coli
Authors: Enoch Harry G. , Lester Robert L.
Published: January 2020

The role of selenium and molybdenum in the metabolism of
Escherichia coli
was explored by growing cells in a simple salts medium and examining the metabolic consequences of altering the concentration of molybdenum and selenium compounds in the medium. The addition of tungstate increased the molybdate deficiency of this medium, as reflected by lowered levels of enzyme systems previously recognized to require compounds of molybdenum and selenium for their formation [formate-dependent oxygen reduction, formate dehydrogenase (FDH) (EC 1.2.2.1), and nitrate reductase (EC 1.9.6.1)]. The requirement for selenium and molybdenum appears to be unique to the enzymes of formate and nitrate metabolism since molybdate- and selenite-deficient medium had no effect on the level of several dehydrogenase and oxidase systems, for which the electron donors were reduced nicotinamide adenine dinucleotide, succinate,
d
- or
l
-lactate, and glycerol. In addition, no effect was observed on the growth rate or cell yield with any carbon source tested (glucose, glycerol,
dl
-lactate, acetate, succinate, and
l
-malate) when the medium was deficient in molybdenum and selenium.
dl
-Selenocystine was about as effective as selenite in stimulating the formation of formate dehydrogenase, whereas
dl
-selenomethionine was only 1% as effective. In aerobic cells, an amount of FDH was formed such that 3,200 or 3,800 moles of formate were oxidized per min per mole of added selenium (added as
dl
-selenocystine or selenite, respectively).
Effect of Growth Conditions on the Formation of the Relaxation Complex of Supercoiled ColE1 Deoxyribonucleic Acid and Protein in
Escherichia coli
Authors: Clewell Don B. , Helinski Donald R.
Published: January 2020

Colicinogenic factor E1 (ColE1) is present in
Escherichia coli
strain JC411 (ColE1) cells to the extent of about 24 copies per cell. This number does not appear to vary in situations which give rise to twofold differences in the amount of chromosomal deoxyribonucleic acid (DNA) present per cell. If cells are grown in the absence of glucose, approximately 80% of the ColE1 molecules can be isolated as strand-specific DNA-protein relaxation complexes. When glucose is present in the medium, only about 30% of the plasmid molecules can be isolated as relaxation complexes. Medium shift experiments in which glucose was removed from the medium indicate that within 15 min after the shift the majority (>60%) of the plasmid can be isolated as relaxation complex. This rapid shift to the complexed state is accompanied by a two- to threefold increase in the rate of plasmid replication. The burst of replication and the shift to the complexed state are both inhibited by the presence of chloramphenicol. Inhibition of protein synthesis in log cultures by the addition of chloramphenicol or amino acid starvation allows ColE1 DNA to continue replicating long after chromosomal replication has ceased. Under these conditions, noncomplexed plasmid DNA accumulates while the amount of DNA that can be isolated in the complexed state remains constant at the level that existed prior to treatment. In the presence of chloramphenicol, there appears to be a random dissociation and association of ColE1 DNA and “relaxation protein” during or between rounds of replication.
Yeast Membrane Vesicles: Isolation and General Characteristics
Authors: Christensen Michael S. , Cirillo Vincent P.
Published: January 2020

Yeast membrane vesicles are formed when packed yeast are ground manually in a porcelain mortar and pestle with glass beads (0.2 mm diameter). These vesicles can be separated from the other components of the grinding mixture by a combination of centrifugation steps and elution from a column of the same glass beads (0.2 mm diameter). Isolated vesicles are osmotically sensitive, contain cytoplasmic components, and have energy-independent transport function. They are unable to metabolize glucose, but have respiratory function which is thought to be associated with intravesicular mitochondria. Invertase and oligomycin-insensitive adenosine triphosphatase are present in lysed vesicle preparations, and the appropriateness of these enzyme activities as membrane markers is discussed.
Micro-Complement Fixation in
Klebsiella
Classification
Authors: Steffen David L. , Cocks Gary T. , Wilson Allan C.
Published: January 2020

The alkaline phosphatases of 29 strains of bacteria assigned by various authors to the genera
Aerobacter, Klebsiella
and
Enterobacter
were compared by the micro-complement fixation technique. On the basis of phosphatase resemblance, we recommend that all strains hitherto assigned to
Aerobacter aerogenes
and
Enterobacter aerogenes
be assigned to the genus
Klebsiella
.
Regulation of Arginase Activity by Intermediates of the Arginine Biosynthetic Pathway in
Neurospora crassa
Authors: Salceda J. Mora, R. , Sanchez S.
Published: January 2020

It has been found that, in
Neurospora crassa
, arginine synthesized from exogenous citrulline was not as effectively hydrolyzed as exogenous arginine. This was explained by the observed inhibition of arginase in vitro and in vivo by citrulline. The high arginine pool formed from exogenous citrulline feedback inhibits the arginine pathway. These two factors allow exogenous citrulline to be used adventitiously and efficiently as an arginine source. Finally, it was found that ornithine was a strong inhibitor of arginase. This suggests that the characteristically high ornithine pool of minimal cultures of
Neurospora
may act to control a potentially wasteful catabolism of endogenous arginine by arginase.
Isolation and Characterization of a Phosphonomycin-Resistant Mutant of
Escherichia coli
K-12
Authors: Venkateswaran P. S. , Wu H. C.
Published: January 2020

A mutant was isolated from
Escherichia coli
K-12 which showed increased resistance towards phosphonomycin, a new bactericidal antibiotic recently isolated from strains of
Streptomyces
. Evidence is presented which suggests that this mutant is resistant to lysis by phosphonomycin because of a lower affinity of phosphoenolpyruvate: uridine diphospho-
N
-acetylglucosamine enolpyruvyl transferase for this antibiotic. This mutant was also found to be temperature-sensitive in growth. At 42 C mutant cells grew poorly, and the rate of incorporation of
3
H-diaminopimelic acid into trichloroacetic acid-insoluble material was also greatly reduced. Genetic studies indicate that the increased resistance toward phosphonomycin and temperature sensitivity in growth of this mutant are probably the consequences of a single mutation.
Abnormal Excision and Transfer of Chromosomal Segments by a Strain of
Escherichia coli
K-12
Authors: Bergquist Peter L. , Adelberg Edward A.
Published: January 2020

PB15 is an Hfr strain of
Escherichia coli
K-12. It arose from an F′ strain carrying a temperature-sensitive F-
gal
by an event which blocked the detachment of F-
gal
in the normally reversible integration process. In PB15, the detachment of F-
gal
by a second mechanism can now be detected: this mechanism results in the excision and transfer of extended chromosomal segments which include the integrated F-
gal
; the excised segments are inferred to have circularized. Their excision, which is independent of the
recA
+
allele, occurs at an unusually high rate during conjugation; a mutant F-initiator protein is suggested as the cause of this phenomenon. After their establishment in recipients, the enlarged F-genotes undergo further deletions of included donor genes by a process which is again
recA
+
-independent. In Rec
+
, but not in Rec
−
, cells, a high proportion of the deleted fragments are rescued by integration into the recipient's chromosome.
Axenic Culture of Myxamoebae of the Myxomycete
Physarum polycephalum
Authors: Goodman E. M.
Published: January 2020

Myxamoebae of the acellular slime mold
Physarum polycephalum
have been cultured axenically in a soluble medium. The growth medium contains bovine serum albumin, embryo extracts, liver infusion broth, peptone, and glucose. Cell densities ranging from 3 × 10
6
to 5 × 10
6
cells/ml have been obtained with this medium. To date, myxamoebae have been serially transferred more than 100 times without deleterious effect.
Time Course of Purine Nucleoside Phosphorylase Occurrence in Sporulation of
Bacillus cereus
Authors: Engelbrecht Helen L.
Published: January 2020

Purine nucleoside phosphorylase (EC 2.4.2.1) from
Bacillus cereus
T was examined at hourly intervals during growth and sporulation. The enzyme has maximal activity in extracts prepared from cells during stages I and II. The activity during exponential growth is only 6.6% of the maximum and that in free spores is only 3.3%. Conservation of the purine nucleoside phosphorylase during sporulation is apparent as shown by the gradual increase in heat resistance.
Synthesis, No Synthesis, or Synthesis and Degradation of Ribosomal Ribonucleic Acid in Various
Escherichia coli
Strains Starved for an Amino Acid
Authors: Craig E. , Schlessinger D. , Gurgo C.
Published: January 2020

A standard stringent strain of
Escherichia coli
makes little or no ribosomal ribonucleic acid (RNA) during starvation for an essential amino acid, whereas the isogenic relaxed strain makes both ribosomal and messenger RNA. A third class of strains was found which continues to make ribosomal RNA during starvation, but the RNA made is apparently unstable. There is little accumulation of RNA in the third class of strains, and few complete newly formed chains of
3
H-ribosomal RNA are observed in sedimentation analyses, even after long labeling times.
Mutants ofSalmonella typhimuriumThat Are Insensitive to Catabolite Repression of Proline Degradation
Authors: Newell Sara Lee , Brill Winston J.
Published: January 2020

InSalmonella typhimuriumthe two enzymes of proline catabolism, proline oxidase and Δ1-pyrroline-5-carboxylic acid dehydrogenase, are subject to catabolite repression when the cells are grown in the presence of glucose. Mutants partially relieved of catabolite repression (PutR) for the proline catabolic enzymes have been isolated by selection on agar plates containing glucose and proline. The specificity of the catabolite repression-insensitive character for the enzymes of proline utilization has been confirmed by an analysis of other unrelated catabolic enzymes. Histidase and amylomaltase of the mutant strains are equally as sensitive to glucose repression as are the enzymes from the wild type. All four PutR mutants exhibit higher induced and higher basal levels of proline oxidase as compared with the corresponding wild-type levels. The mutations of three strains tested are cotransducible with constitutive, pleiotrophic-negative and structural gene mutations of theputregion. Three-factor crosses indicate that twoputRmutations are located at one end of the cluster ofputmutations.
Characterization of Strong Polar Mutations in a Region Immediately Adjacent to the
l
-Arabinose Operator in
Escherichia coli
B/r
Authors: Eleuterio Marianne , Griffin Barbara , Sheppard David E.
Published: January 2020

Seven
l
-arabinose-negative mutations are described that map in three genetically distinct regions immediately adjacent to the
araO
(operator) region of the
l
-arabinose operon. All seven mutants revert spontaneously, exhibit a
cis
-dominant,
trans
-recessive polarity effect upon the expression of
l
-arabinose isomerase (gene
araA
), and fail to respond to amber, ochre, or UGA suppressors. Three of these mutants exhibit absolute polarity and are not reverted by the mutangens 2-aminopurine, diethyl sulfate, and ICR-191. These may have arisen as a consequence of an insertion mutation in gene
araB
or in the initiator region of the
l
-arabinose operon. The four remaining mutants exhibit strong but not absolute polarity on gene
araA
and respond to the mutagens diethyl sulfate and ICR-191. Three of these mutants are suppressible by two independently isolated suppressors that fail to suppress known nonsense codons. Partially polar Ara
+
revertants with lesions linked to
ara
are obtained from three of the same four mutants. These polar mutants, their external suppressors, and their partially polar revertants are discussed in terms of the mechanism of initiation of expression of the
l
-arabinose operon.
Factors Affecting the Activity of the Lactate Dehydrogenase of
Streptococcus cremoris
Authors: Jonas H. A. , Anders R. F. , Jago G. R.
Published: January 2020

Studies with partially purified extracts of the nicotinamide adenine dinucleotide-linked
l
(+)-lactate dehydrogenase of
Streptococcus cremoris
US3 showed that fructose-1,6-diphosphate (FDP) was essential for the catalytic reduction of pyruvate in the
p
H range 5.0 to 7.0, outside of which the organism does not grow. In the absence of FDP, enzyme activity was observed only in the region of
p
H 8.0. The optimal
p
H for the oxidation of lactate was approximately 8.0 in the presence and absence of FDP. The FDP-activated enzyme was markedly inhibited by inorganic phosphate. The enzyme lost activity on standing at 5 C in alkaline triethanolamine, was quite stable at
p
H 6.0 to 6.5, and underwent irreversible denaturation below
p
H 5.0. Inorganic phosphate or FDP increased the stability of the enzyme in alkaline buffers. Some distinguishing properties of individual lactate dehydrogenases, activated by FDP, are discussed.
Effect of Spermine on the Uptake of Amino Acids in
Micrococcus lysodeikticus
Authors: Ariel Miriam , Grossowicz Nathan
Published: January 2020

Spermine inhibited the transport of neutral aliphatic amino acids (valine, leucine, isoleucine, alanine, and glycine) into cells of
Micrococcus lysodeikticus
. On the other hand, spermine did not affect the uptake of basic (arginine and histidine), acidic (glutamic acid), or aromatic (phenylalanine and tyrosine) amino acids. Inhibition of uptake of the neutral amino acids by spermine is apparently of a noncompetitive nature; the
V
max
decreased, whereas the apparent
K
m
remained unaltered. The inhibition is most likely due to a specific binding of spermine to the carrier(s) of these amino acids. Related polyamines, spermidine and cadaverine, also caused inhibition of valine uptake, though to a lesser extent; spermidine was less active than spermine, and cadaverine showed the weakest effect of all. Valine, leucine, and isoleucine were transported into
M. lysodeikticus
cells by a common carrier as evidenced from competition experiments. The uptake of these amino acids is an active process; it was temperature-dependent and inhibited by azide (10
−1
m
to 2.5 × 10
−2
m
) and dinitrophenol (10
−3
m
). The intracellular concentration of valine was 100-fold higher than in the medium.
Production of an Autoinhibitor by a Thermophilic Bacillus
Authors: Chou T. W. , Greasham R. , Tannenbaum S. R. , Demain A. L.
Published: January 2020

Premature cessation of rapid, exponential growth and a low final cell yield were observed with a thermophilic bacillus in a glucose-mineral salts-vitamin medium. Restricted growth was not due to nutrient or oxygen limitation, to depressed
p
H, or to the physical effects of “crowding.” Glucose conversion to cellular material was efficient at a low glucose charge (0.1%), but decreased with increasing concentrations of glucose. The likelihood that an autoinhibitor(s) was being produced was considered. Further studies revealed that an autoinhibitor appeared in the culture supernatant fluid at the end of the exponential phase. The factor was soluble in 75% ethanol which precipitated a large amount of extracellular slime. The crude inhibitor in the alcohol filtrate was dialyzable and withstood 3 hr of incubation at
p
H 2 or 12, and 30 min of boiling.
Purification of Sex Pili from
Escherichia coli
Carrying a Derepressed F-Like R Factor
Authors: Beard J. P. , Howe T. G. B. , Richmond M. H.
Published: January 2020

A procedure for the purification of sex pili is described.
Escherichia coli
K-12 carrying Rl
drd
19 was grown in nutrient broth and blended at the time of peak sex pilus production. The cells were removed by centrifugation, and the supernatant fraction was concentrated, dialyzed, and clarified in an ultrafiltration system. After an additional blend and a clearing spin, the material was centrifuged in a CsCl gradient, and the fractions containing the sex pili were subjected to isoelectric focusing. About 5 mg of intact pili of approximately 98% purity were obtained by this method from about 100 g (wet weight) of cells.
Dark Dependence of Meiosis at Elevated Temperatures in the Basidiomycete
Coprinus lagopus
Authors: Lu Benjamin C.
Published: January 2020

Under continuous-light regimen
Coprinus lagopus
can enter and complete meiosis at 25 C, but is unable to do so at 35 C. The temperature-sensitive and the dark-dependent period is 10 hr before karyogamy. It is conjectured that the basidia are programmed for the initiation of meiosis during that 10-hr period.
Suppressor of Phosphofructokinase Mutations of
Escherichia coli
Authors: Morrissey A. T. E. , Fraenkel D. G.
Published: January 2020

The known locus of fructose-6-phosphate kinase mutations (
pfkA
) in
Escherichia coli
is at 76 min on the genetic map. We have now found another gene,
pfkB
, at 33 min, mutation of which suppresses
pfkA
mutations. The suppression is not informational, and
pfkB
may be a second gene for fructose-6-phosphate kinase activity.
Some Unique Properties of the Deoxyribonucleic Acid-Bearing Portion of the Bacterial Membrane
Authors: Ballesta J. P. , Cundliffe E. , Daniels M. J. , Silverstein Judith L. , Susskind Miriam M. , Schaechter M.
Published: January 2020

By using the M-band technique we have shown that portions of the membranes of
Bacillus megaterium
and
Escherichia coli
vary in their affinity for magnesium-Sarkosyl crystals and in phospholipid composition. The portion to which deoxyribonucleic acid is attached comprises as little as 4% of the total cell membrane, has a particularly high degree of affinity for magnesium-Sarkosyl crystals, and is rich in phosphatidylethanolamine. The M-band fractionation does not depend on the use of lysozyme.
Activity of Deoxyribonucleic Acid Fragments of Defined Size in
Bacillus subtilis
Transformation
Authors: Morrison D. A. , Guild Walter R.
Published: January 2020

The transforming activity of
Bacillus subtilis
deoxyribonucleic acid (DNA) that had been sheared and purified with respect to size by sucrose gradient sedimentation is given as a function of the DNA molecular weight. It is shown (i) that fragments of median molecular weight 1.2 × 10
6
have finite activity (10
−4
), (ii) that the shape of the activity-versus-molecular weight function is qualitatively similar to that observed previously for
Diplococcus pneumoniae
, and (iii) that this shape precludes interpretation in terms of critical size models.
Potassium Content During Growth and Sporulation in
Bacillus subtilis
Authors: Eisenstadt Eric
Published: January 2020

Vegetative and sporulating cells of
Bacillus subtilis
retain a higher level of internal potassium than do nonsporulating stationary-phase cells. The addition of manganese to nonsporulating stationary-phase cells, at concentrations required for sporulation, rapidly stimulates uptake and net accumulation of potassium and induces sporulation.
Mutant of
Escherichia coli
Deficient in the Synthesis of
cis
-Vaccenic Acid
Authors: Gelmann Edward P. , Cronan John E.
Published: January 2020

A temperature-sensitive unsaturated fatty acid (
fabA
) auxotroph of
Escherichia coli
was found also to be deficient in the elongation of palmitoleic acid to
cis
-vaccenic acid. Reversion and transductional analyses demonstrate that this second phenotype and the
fabA
mutation are independent in action and are not cotransduced. The deficiency in conversion of palmitoleic acid to
cis
-vaccenic acid was also demonstrated in vitro, and these results strongly suggest this phenotype is due to a deficiency in an elongation enzyme. We suggest that the phenotype may have been selected during growth because it can physiologically compensate for the
fabA
lesion. In
fab
+
strains, the inability to synthesize
cis
-vaccenic acid is physiologically asymptomatic. Such strains grow normally at all temperatures tested and are not sodium sensitive. Although the parental strain has an increased amount of
cis
-vaccenic acid in cells grown at 15 C, the mutant does not. Since the mutant grows normally at 15 C, the data indicate that increased amounts of
cis
-vaccenic acid are not required for growth at 15 C.
Consequences of Glycerol Deprivation on the Synthesis of Membrane Components in a Glycerol Auxotroph of
Staphylococcus aureus
Authors: Ray Paul H. , Lillich Thomas T. , White David C.
Published: January 2020

In a glycerol auxotroph of
Staphylococcus aureus
, the deprivation of glycerol affected the formation of certain membrane components. (i) There was synthesis of fatty acids at the predeprivation rate even though the fatty acids synthesized accumulated as free fatty acids rather than as esterified fatty acids; (ii) there was a complete cessation of phospholipid and vitamin K isoprenologue biosynthesis; (iii) there was conservation of the glycerol esters of the complex phospholipids and glucolipids; (iv) there was an immediate decrease in the rate of synthesis of monoglucoslydiglyceride (30%) and diglucosyldiglyceride (60%); (v) there was a 50% decrease in the rate of synthesis of the polar and nonpolar carotenoids; (vi) there was synthesis of protoheme, heme
a
, and nonspecific membrane protein at the predeprivation rate; and (vii) there was an abrupt cessation in the formation of new, functional glycine transport activity.
Reversion of Streptococcal Protoplasts
Authors: Bibel David J. , Lawson John W.
Published: January 2020

The reversion of protoplasts of
Streptococcus faecium
was examined by light and scanning electron microscopy. Regularly shaped streptococci emerged from the narrow region of large, oval protoplasts.
Exosporium Formation in Sporulating Cells ofClostridium botulinum78A
Authors: Stevenson Kenneth E. , Vaughn Reese H.
Published: January 2020

In sporulating cells ofClostridium botulinumtype A (NCA strain 78A), formation of exosporia was initiated laterally in the sporangia before the synthesis of the spore cortex. Mature spores were enveloped by multilayered exosporia; the layers were uniform in appearance, approximately 3 nm thick, with a center-to-center distance of 7 nm.
Protein Synthesis During Fungal Spore Germination: Differential Protein Synthesis During Germination of
Botryodiplodia theobromae
Spores
Authors: Van Etten James L. , Roker Henry R. , Davies Eric
Published: January 2020

The preformed messenger ribonucleic acid in
Botryodiplodia theobromae
spores directs the synthesis of several relatively stable polypeptides
Incompatibility Groups and the Classification of
fi
−
Resistance Factors
Authors: Chabbert Y. A. , Scavizzi M. R. , Witchitz J. L. , Gerbaud G. R. , Bouanchaud D. H.
Published: January 2020

Incompatibility between R factors has been reported by several authors, and four incompatibility groups have already been described by Datta and Hedges among R
fi
−
factors. The stability of 12 plasmids in pairs was studied after 116 crosses, and five new groups were found, designated 5, 6, 7, 8, and 9. Each plasmid studied belongs to one single group. Incompatibility between plasmids in pairs is a clear-cut phenomenon, is easy to observe, and can provide a reliable method for recognizing and classifying resistance factors, and for tracing their spread among bacterial species.
Conditional Lethality of Deletions Which Include
uvrB
in Strains of
Escherichia coli
Lacking Deoxyribonucleic Acid Polymerase I
Authors: Shizuya Hiroaki , Dykhuizen Daniel
Published: January 2020

Deletions of the
uvrB
gene were not obtained in
polA1
strains of
Escherichia coli
either by selecting for spontaneous deletions or by transduction from strains carrying such deletions. A strain forming a temperature-sensitive deoxyribonucleic acid polymerase I and carrying a deletion of the
uvrB
gene is inviable at the nonpermissive temperature.
Polyfunctional Penicillinase Plasmid in
Staphylococcus epidermidis
: Bacteriophage Restriction and Modification Mutants
Authors: Schaefler S.
Published: January 2020

Growth of multiply resistant
Staphylococcus epidermidis
BV strains at 45 C resulted in the independent elimination of tetracycline resistance, of kanamycin resistance coupled with oxacillin resistance, or of penicillinase activity. The
p
H optimum for the elimination of kanamycin and oxacillin resistance was 5.6, whereas that for elimination of penicillinase activity was 8.0. The genetic determinant for penicillinase activity was linked with the genetic determinants for the active uptake of mannitol and β-glucosides, ribose fermentation, and phospho β-glucosidase activity. The penicillinase linkage group also contained determinants for phage adsorption, restriction, and modification, and for growth factor requirements of still unknown nature. The same linkage group, which is apparently of extrachromosomal nature, was eliminated from several
S. epidermidis
BV strains. By selection for novobiocin resistance, deletion mutants affecting several loci of the penicillinase plasmid were isolated. The isolation of restriction-negative and modification-negative mutants which retained phage susceptibility allowed the investigation of restriction and modification phenomena. A preliminary deletion map of the polyfunctional penicillinase plasmid is proposed.
Myxospore Formation in
Myxococcus xanthus
: Chemical Changes in the Cell Wall During Cellular Morphogenesis
Authors: Johnson Roosevelt Y. , White David
Published: January 2020

Vegetative cells of
Myxococcus xanthus
(strain FB) were induced to form myxospores by the glycerol induction technique. Several structural changes took place in the peptidoglycan during myxospore formation. The percent of the peptidoglycan comprised of monomer (disaccharide peptide) decreased from about 20% to approximately 7%. The proportion of the total diaminopimelic acid possessing a free amino group decreased about 11%. A carbohydrate containing only glucose was found to be bound, possibly covalently, to the vegetative cell and myxospore peptidoglycan. The amount of carbohydrate relative to peptidoglycan decreased by two-thirds during myxospore formation. None of the above changes in the peptidoglycan were observed in a mutant (strain GNI) of
M. xanthus
which was unable to convert to myxospores when incubated in the glycerol induction medium, or in the parental wild type (FB) when it was incubated in induction medium lacking the myxospore inducer, glycerol.
Properties and Purification ofN-Acetylmuramyl-l-Alanine Amidase fromStaphylococcus aureusH
Authors: Singer Howard J. , Wise Edmund M. , Park James T.
Published: January 2020

The principal autolytic enzyme activity of the cell sap ofStaphylococcus aureusH has been purified 400-fold. It is anN-acetylmuramyl-l-alanine amidase. This enzyme has a molecular weight of 8 to 10 × 105, apH optimum of 7.3, an ionic strength optimum of 0.16mand aKmof 10−3mmurein repeating units.
Cell Wall Peptidoglycan Mutants of
Escherichia coli
K-12: Existence of Two Clusters of Genes,
mra
and
mrb
, for Cell Wall Peptidoglycan Biosynthesis
Authors: Miyakawa Tokichi , Matsuzawa Hiroshi , Matsuhashi Michio , Sugino Yoshinobu
Published: January 2020

Temperature-sensitive mutants of
Escherichia coli
K-12 which cannot form cell wall peptidoglycan at 42 C were isolated. The thermosensitive steps were characterized biochemically, and the genes coding the enzymes of peptidoglycan synthesis were mapped. These genes were in two clusters: one group, located at about 1.5 min between
leu
and
azi
, was designated as
mra
(murein a); the second group, located at about 77.5 min close to
argH
and
metB
, was designated as
mrb
(murein b, with the order
metB-argH-mrb
). No simple relations were found between the gene location and the order or localization of enzymes involved in the sequence of reactions of cell wall peptidoglycan biosynthesis.
Genetic Regulation of Cell Division Initiation in
Bacillus subtilis
Authors: Mendelson Neil H. , Cole Roger M.
Published: January 2020

The growth and division properties of a temperature-sensitive mutant of
Bacillus subtilis
defective in the initiation of cell division have been studied. Log-phase cells transferred from 30 to 45 C continue to increase in length but fail to initiate new divisions. Deoxyribonucleic acid synthesis continues at 45 C, and genomes are segregated along the filament length. When filaments are returned to 30 C, division initiation resumes, and the long multinucleate clones are partitioned into normal-size cells. Occasionally, multiple cross walls initiate in close proximity, resulting in tiny cells, some of which are anucleate. Division resumption is sensitive to protein synthesis inhibitors, suggesting there is a new protein required for the initiation of division in filaments.
Phospholipid Composition and Metabolism ofMicrococcus denitrificans
Authors: Wilkinson Brian J. , Morman Manuel R. , White David C.
Published: January 2020

The phospholipid composition ofMicrococcus denitrificanswas unusual in that phosphatidyl choline (PC) was a major phospholipid (30.9%). Other phospholipids were phosphatidyl glycerol (PG, 52.4%), phosphatidyl ethanolamine (PE, 5.8%), an unknown phospholipid (5.3%), cardiolipin (CL, 3.2%), phosphatidyl dimethylethanolamine (PDME, 0.9%), phosphatidyl monomethylethanolamine (PMME, 0.6%), phosphatidyl serine (PS, 0.5%), and phosphatidic acid (0.4%). Kinetics of32P incorporation suggested that PC was formed by the successive methylations of PE. Pulse-chase experiments with pulses of32P or acetate-1-14Cto exponentially growing cells showed loss of isotopes from PMME, PDME, PS, and CL with biphasic kinetics suggesting the same type of multiple pools of these lipids as proposed in other bacteria. The major phospholipids, PC, PG, and PE, were metabolically stable under these conditions. The fatty acids isolated from the complex lipids were also unusual in being a simple mixture of seven fatty acids with oleic acid representing 86% of the total. Few free fatty acids and no non-extractable fatty acids associated with the cell wall or membrane were found.
Metabolism of Gentiobiose in
Aerobacter aerogenes
Authors: Palmer Richard E. , Anderson Richard L.
Published: January 2020

Cleavage of gentiobiose in cell extracts of gentiobiose-grown
Aerobacter aerogenes
was dependent on the presence of adenosine 5′-triphosphate (ATP). The enzymes that participate in the overall reaction were shown to be a β-glucoside kinase, which catalyzes the phosphorylation of gentiobiose with ATP to form gentiobiose monophosphate [6-
O
-phosphoryl-β-
d
-glucopyranosyl-(1 → 6)-
d
-glucose], and a phospho-β-glucosidase, which catalyzes the hydrolytic cleavage of gentiobiose monophosphate to form equimolar amounts of
d
-glucose and
d
-glucose 6-phosphate. Although the β-glucoside kinase was previously shown to catalyze the phosphorylation of many β-glucosides that serve as growth substrates (i.e., gentiobiose, cellobiose, cellobiitol, salicin, arbutin, methyl β-
d
-glucoside, and phenyl β-
d
-glucoside), mutant analysis and induction studies indicate that it functions only in the metabolism of gentiobiose, cellobiose, and cellobiitol.
Scanning Electron Microscopy of Spore Germination in
Dictyostelium discoideum
Authors: George R. P. , Albrecht R. M. , Raper K. B. , Sachs I. B. , MacKenzie A. P.
Published: January 2020

The ellipsoidal dormant spores of
Dictyostelium dicoideum
prepared by freeze-drying had a uniform, compact appearance with fine wrinkles or ridges on the surface. Swollen spores were uneven in appearance, without fine wrinkles but with a seemingly expanded surface covering. The surfaces of the postgermination spore husks appeared unaltered except for a single straight exit slit along the longitudinal plane.
Structural Changes Associated with Extraction of Group E Spore Antigen of
Clostridium botulinum
Authors: Hawirko R. Z. , Chung K. L. , Magnusson A. J. C. , Emeruwa A. C.
Published: January 2020

Spores of type E Beluga strain of
Clostridium botulinum
, which were hydrolyzed with HCl to remove the spore-specific antigen, showed a spore coat which was thinner and projected into the exosporium with multiple protuberances. The changes observed suggest that the antigen is a component of the spore coat connected with the maintenance of rigidity.
Location of the Region Controlling Host Specificity (
hs
II) with Respect to Drug Resistance Markers on the
fi
−
R Factor, N-3
Authors: Hattman Stanley , Cousens Lawrence
Published: January 2020

The region controlling host specificity (
hs
II) has been mapped, by P22 transduction, with respect to drug resistance markers carried on the
fi
−
R factor, N-3. The relative linear sequence of cotransducible markers is Tc-Su-Sm-
hs
II.
Inhibition of Thiamine Transport by Chloroethylthiamine in
Escherichia coli
Authors: Iwashima Akio , Nose Yoshitsugu
Published: January 2020

Chloroethylthiamine was found to inhibit an entrapment of thiamine as thiamine monophosphate by blocking thiamine monophosphokinase in the cytoplasm after thiamine was taken up by the cells of
Escherichia coli
.