bluuebunny/crossref_metadata_2025 huggingface dataset:
Nucleic Acid Homologies Among Species of
Saccharomyces
Authors: Bicknell J. N. , Douglas Howard C.
Published: January 2020

Evolutionary divergence among species of the yeast genus
Saccharomyces
was estimated from measurements of deoxyribonucleic acid (DNA)/DNA and ribosomal ribonucleic acid (RNA)/DNA homology. Much diversity was found in the DNA base sequences with several species showing little or no homology to the three reference species,
S. cerevisiae, S. lactis
, and
S. fragilis
. These three reference species also showed little or no homology to each other. On the other hand the diversity among ribosomal RNA base sequences was small since most species showed a high degree of homology to the reference species. The arrangement of species based on ribosomal RNA homologies agrees in most cases with current taxonomic groupings. A yeast hybrid (
S. fragilis
×
S. lactis
) was shown to contain two nonhomologous genomes. A minimum genome size of 9.2 × 10
9
daltons for
S. cerevisiae
was calculated from the rate of DNA renaturation.
Growth in Volume of
Euglena gracilis
During the Division Cycle
Authors: Kempner E. S. , Marr A. G.
Published: January 2020

The distribution of volumes of
Euglena gracilis
cells was measured conductimetrically. The volume spectrum of cultures in balanced growth was analyzed by the method of Collins and Richmond. The kinetics of volume increase of
Euglena
is neither linear nor exponential; the growth rate of small and large cells is low, but intermediate size cells show the largest growth rate.
Chemical Morphology of Glucan and Chitin in the Cell Wall of the Yeast Phase of
Paracoccidioides brasiliensis
Authors: Carbonell L. M. , Kanetsuna F. , Gil F.
Published: January 2020

Short and thick fibers were observed on the outer surface of the yeast phase of
Paracoccidioides brasiliensis
, and long and thin fibers were seen on the inner surface. The long fibers disappear with chitinase treatment and are composed of chitin. The short fibers disappear under alkali treatment and are composed of α-glucan. Comparisons with α-(1 → 3)-glucan isolated from
Aspergillus niger
and
Polyporus betulinus
and with chitin from fungal origin support our point of view.
Cytochrome Composition of Some Members of the
Actinoplanaceae
Authors: Domnas A. , Grant Neil G.
Published: January 2020

The cytochrome composition of 19 strains of
Actinoplanaceae
has been investigated. The principal cytochrome found was cytochrome
b
, and occasional strains showed the presence of cytochrome
a
.
Effect of Actinomycin D on the Transfer of Ribonucleic Acid from Nucleus to Cytoplasm in
Lactobacillus acidophilus
Authors: Chai Ning-Chun , Lark K. G.
Published: January 2020

After starvation for deoxyribosides, the deoxyribonucleic acid (DNA) of
Lactobacillus acidophilus
is restricted to a localized region of the cell.
3
H-uracil is first incorporated into such a restricted region but subsequently is found throughout the cell. This spread occurs despite the absence of protein synthesis and a major reduction in the rate of ribonucleic acid (RNA) synthesis. However, blocking RNA synthesis with actinomycin D restricts incorporation to a localized region of the cell. It is concluded that uracil is first incorporated into RNA in the bacterial nucleus from which it subsequently spreads through the cell. Actinomycin D could prevent this spread by preventing the completion of RNA molecules, which therefore do not dissociate from the DNA template.
Stability and Comparative Transport Capacity of Cells, Mureinoplasts, and True Protoplasts of a Gram-Negative Bacterium
Authors: De Voe I. W. , Thompson J. , Costerton J. W. , MacLeod Robert A.
Published: January 2020

The outer layers of the cell envelope of a pseudomonad of marine origin were removed by washing the cells in 0.5
m
NaCl followed by suspension in 0.5
m
sucrose. The term mureinoplast has been suggested for the rod-shaped forms which resulted from this treatment. As previously established, these forms lacked the outer cell wall layers but still retained a rigid peptidoglycan structure. Mureinoplasts remained stable if suspended in a balanced salt solution containing 0.3
m
NaCl, 0.05
m
MgSO
4
, and 0.01
m
KCl but, unlike whole cells, lost ultraviolet (UV)-absorbing material if suspended in 0.5
m
NaCl or 0.05
m
MgCl
2
. Sucrose added to the balanced salt solution also enhanced the loss of UV-absorbing material. Addition of lysozyme to suspensions of mureinoplasts in the balanced salt solution produced spherical forms which, by electron microscopy and the analysis of residual cell wall material, appeared to be true protoplasts. Only undamaged mureinoplasts, as judged by their capacity to fully retain α-aminoisobutyric acid, were capable of being converted to protoplasts. Protoplasts and undamaged mureinoplasts retained 100% transport capacity when compared to an equal number of whole cells. The Na
+
requirement for transport of α-aminoisobutyric acid and the sparing action of Li
+
on this Na
+
requirement were the same for both protoplasts and whole cells. These observations indicate that, in this gram-negative bacterium, the cell wall does not participate in the transport process though it does stabilize the cytoplasmic membrane against changes in porosity produced by unbalanced salt solutions. The results also indicate that the requirements for Na
+
for transport and for the retention of intracellular solutes are manifested at the level of the cytoplasmic membrane.
Ultrastructural Changes Associated with Germination and Outgrowth of an Appendage-Bearing Clostridial Spore
Authors: Samsonoff William A. , Hashimoto T. , Conti S. F.
Published: January 2020

The sequence of events occurring during the germination and outgrowth of appendage-bearing spores of
Clostridium bifermentans
was studied by phase-contrast and electron microscopy. The mature spore was characterized ultrastructurally as having the normal spore components as well as long tubular appendages which orginated from the surface of the spore coat. Spores were incompletely enclosed by a distinctly laminated exosporium which possessed hairlike projections on its outermost layer. During germination, structural changes were observed in the core, core wall, cortex, and spore coat layers. Cortical material was extruded from the spore during outgrowth, which usually occurred from the pole opposite the appendages. The subunits comprising the structure of the appendages and the morphology of the mature appendages were observed. No discernible changes could be observed in the spore appendages during germination and outgrowth.
Detection of a β-Lactamase Markedly Active Against Carbenicillin in a Strain of
Pseudomonas aeruginosa
Authors: Newsom S. W. B. , Sykes R. B. , Richmond M. H.
Published: January 2020

Examination of the substrate profile of a number of β-lactamases synthesized by strains of
Pseudomonas aeruginosa
has shown the presence of at least two distinct types of enzyme, one of which is more active against carbenicillin than against benzyl penicillin.
Stimulation of Galactokinase Synthesis in
Escherichia coli
by Adenosine 3′,5′-Cyclic Monophosphate
Authors: Tao Mariano , Schweiger Manfred
Published: January 2020

Adenosine 3′,5′-cyclic monophosphate (cyAMP) stimulates the rate of synthesis of galactokinase in glycerol-grown
Escherichia coli
both when production of the enzyme is induced by
d
-fucose and when it is repressed by glucose in the presence of inducer. cyAMP also stimulates the synthesis of galactokinase in constitutive strains B78A (R
−
) and R10 (O
c
), and overcomes the transient repression of galactokinase synthesis caused by glucose.
Masking of
Bacillus megaterium
KM Membrane Reduced Nicotinamide Adenine Dinucleotide Oxidase and Solubilization Studies
Authors: Eisenberg R. C. , Yu L. , Wolin M. J.
Published: January 2020

Solubilization of a reduced nicotinamide adenine dinucleotide (NADH)-2,6 dichlorophenol indophenol (DCIP) oxidoreductase associated with the membrane NADH oxidase system of
Bacillus megaterium
KM was effected by treatment with 0.2% sodium deoxycholate, 8
m
urea, or buffer (
p
H 9.0) in the presence of ethyl-enediaminetetraacetate. These treatments inactivated membrane NADH oxidase. It was found that membrane NADH oxidase and NADH-DCIP oxidoreductase were masked in membranes. Several procedures, including brief sonic oscillation, treatment with 0.05% deoxycholate, prolonged stirring at 4 C with 10% glycerol, and washing in the absence of Mg
2+
, unmasked the oxidase and oxidoreductase activities. It was necessary to study the masking and unmasking of these activities to quantitate adequately the effects of solubilization procedures. Further information on the localization of oxidase and oxidoreductase in subcellular fractions and the effects of electron transport inhibitors on NADH oxidation was also obtained.
Formation and Ultrastructure of Extra Membranes in
Escherichia coli
Authors: Weigand R. A. , Shively J. M. , Greenawalt J. W.
Published: January 2020

A temperature-sensitive strain of
Escherichia coli
(strain 0111a
1
) was shown to accumulate membranous structures at 40 C. These “extra membranes” appeared as vesicles or whorls (or both), depending on the time of growth at 40 C. After 2 hr of growth at 40 C, only vesicles were observed in
E. coli
0111a
1
cells; both vesicles and whorls were apparent after 6 hr. The number of cells which contained both types of extra membrane reached a maximum value (75%) after 10 hr of growth at 40 C. Extra membrane production was also studied by using temperature shifts. In shift-up experiments, cells grown at 30 C into early stationary phase accumulated extra membrane after a shift to 40 C. The percentage of
E. coli
0111a
1
cells containing extra membrane decreased significantly after a shift from 40 to 30 C. Phase- and electron-microscopic observations indicated that
E. coli
0111a
1
cells grown at 40 C were larger than
E. coli
0111: B
4
cells grown at either temperature. The ratio of optical density per cell and cell measurements obtained from quantitative electron microscopy confirmed that
E. coli
0111a
1
cells grown at 40 C were about twice as large. Microdensitometer traces indicated that the dimension of a single membrane of either whorls or vesicles was 5.4 nm in peak-to-peak distance (8.8 nm total thickness).
Reevaluation of Bacitracin as a Spore Coat Component
Authors: Marschke C. K. , Bernlohr R. W.
Published: January 2020

Analysis of hydrolysates of highly purified spore coats revealed only small quantities of ornithine, a component of bacitracin. We conclude that the peptide, bacitracin, is not a significant component of spore coats.
Pyridine Nucleotide Transhydrogenase fromAzotobacter vinelandii
Authors: Chung Albert E.
Published: January 2020

A method is described for the partial purification of pyridine nucleotide transhydrogenase fromAzotobacter vinelandii(ATCC 9104) cells. The most highly purified preparation catalyzes the reduction of 300 μmoles of nicotinamide adenine dinucleotide (NAD+) per min per mg of protein under the assay conditions employed. The enzyme catalyzes the reduction of NAD+, deamino-NAD+, and thio-NAD+with reduced nicotinamide adenine dinucleotide phosphate (NADPH) as hydrogen donor, and the reduction of nicotinamide adenine dinucleotide phosphate (NADP+) and thio-NAD+with reduced NAD (NADH) as hydrogen donor. The reduction of acetylpyridine AD+, pyridinealdehyde AD+, acetylpyridine deamino AD+, and pyridinealdehydedeamino AD+with NADPH as hydrogen donor was not catalyzed. The enzyme catalyzes the transfer of hydrogen more readily from NADPH than from NADH with different hydrogen acceptors. The transfer of hydrogen from NADH to NADP+and thio-NAD+was markedly stimulated by 2′-adenosine monophosphate (2′-AMP) and inhibited by adenosine diphosphate (ADP), adenosine triphosphate (ATP), and phosphate ions. The transfer of hydrogen from NADPH to NAD+was only slightly affected by phosphate ions and 2′-AMP, except at very high concentrations of the latter reagent. In addition, the transfer of hydrogen from NADPH to thio-NAD+was only slightly influenced by 2′-AMP, ADP, ATP, and other nucleotides. The kinetics of the transhydrogenase reactions which utilized thio-NAD+as hydrogen acceptor and NADH or NADPH as hydrogen donor were studied in some detail. The results suggest that there are distinct binding sites for NADH and NAD+and perhaps a third regulator site for NADP+or 2′-AMP. The heats of activation for the transhydrogenase reactions were determined. The properties of this enzyme are compared with those of other partially purified transhydrogenases with respect to the regulatory functions of 2′-AMP and other nucleotides on the direction of flow of hydrogen between NAD+and NADP+.
Actinomycin Resistance and Actinomycin Excretion in a Mutant of
Escherichia coli
Authors: Voll Mary Jane , Leive Loretta
Published: January 2020

A mutant of
Escherichia coli
resembles its parent in taking up actinomycin after treatment with ethylenediaminetetraacetic acid but differs in that it survives this uptake and excretes actinomycin at an increased rate.
Reversion of the Frameshift
hisD3018
of
Salmonella typhimurium
Authors: Kohno Tadahiko , Tanemura Shigeji , Yourno Joseph
Published: January 2020

Previous studies on histidinol dehydrogenase from His
+
revertants have shown that the frameshift mutation
hisD3018
is a +1 type, resulting from inclusion of an extra cytidylate residue in messenger ribonucleic acid. Histidinol dehydrogenase from newly isolated spontaneous and
N
-methyl-
N
′-nitro-
N
-nitrosoguanidine (NG)-induced intragenic revertants has been examined for amino acid replacements. The results provide additional evidence that NG can delete guanine plus cytosine base pairs from deoxyribonucleic acid. One spontaneous revertant was found to result from a +2 addition of approximately 16 nucleotide residues before the +1 parent frameshift, and another by a −4 deletion about six residues before the same. Circumstantial evidence suggests the in vivo codon assignment GAG for glutamic acid. A region of histidinol dehydrogenase highly permissive of amino acid changes encoded in the minus (−) phase is now apparent.
Characteristics of a Stable, Filamentous Mutant of a Coccoid Blue-Green Alga
Authors: Ingram L. O. , Van Baalen C.
Published: January 2020

Filamentous mutants were induced in a coccoid blue-green alga,Agmenellum quadruplicatumstrain BG1, after treatment withN-methyl-N′-nitro-N-nitrosoguanidine (NTG). The mutants fall into two general classes: filaments with cross walls and filaments without cross walls. All mutants of these general types derived from BG1 are stable and have growth rates the same as or very similar to the wild type under a variety of conditions. Detailed examination of one mutant, 53SB2, revealed no difference in deoxyribonucleic acid content nor in base ratios. Mutant 53SB2 did not revert to the normal cell size and shape when grown under different physical conditions nor upon the addition of potential reversing agents to the basal medium. It is our general experience that filamentous mutants such as those described here in BG1 are commonly induced in other coccoid blue-green algae after NTG treatment.
Biochemical Properties of Trypanosomatid Lactate Dehydrogenases
Authors: Bacchi C. J. , Ciaccio E. I. , O'Connell Kathleen M. , Hutner S. H.
Published: January 2020

Lactate dehydrogenase (LDH, E.C.1.1.1.27) was found in supernatant (cytoplasmic enzyme) fractions of the trypanosomatid flagellates
Trypanosoma conorhini
and
Crithidia fasciculata
if 10 m
m
cysteine was present in the homogenizing medium. The
T. conorhini
LDH activity with pyruvate as substrate was increased 35% if 5 m
m
cysteine was also included in reaction mixtures.
K
m
values for the
T. conorhini
enzyme were 3.3 × 10
−4
m
with pyruvate, and 1.6 × 10
−4
m
with α-ketobutyrate. Cysteine inhibited α-ketobutyrate reduction. Comparison of trypanosomatid and human serum LDH enzymes with respect to
K
m
, substrate activity and inhibition,
p
H optima, and
K
i
values for oxalate and oxamate indicated that the trypanosomatid isoenzymes differed significantly from serum LDH.
C. fasciculata
LDH was extremely labile, since 59% of the activity was lost 90 min after isolation. The role of LDH enzymes in trypanosomatid metabolism is discussed, and the results are related to other trypanosomatid LDH enzymes. The comparison of homologous enzymes in host and parasite is discussed with regard to metabolic function and a possible model system for chemotherapy.
Effect of Ultraviolet Light on Division and Deoxyribonucleic Acid Synthesis inHaemophilus influenzae
Authors: Kantor George J. , Barnhart B. J.
Published: January 2020

The effects of ultraviolet (UV) light on cell morphology, deoxyribonucleic acid (DNA) synthesis, and protein synthesis in UV-sensitive and UV-resistant strains ofHaemophilus influenzaewere examined. Relatively low doses of UV induce lyses in the sensitive strains but not in the resistant mutant; however, UV temporarily blocks cell division of the resistant mutant, and elongated cells are formed after a period of incubation. Low doses of UV do not stop DNA synthesis in any of the strains examined; however, they do slow the rate of DNA synthesis in a manner consistent with the model correlating the kinetics of postirradiation DNA synthesis with the cell's ability to repair UV-induced DNA lesions. The data are not consistent with a model in which UV causes all DNA synthesis to stop for a time linearly dependent on dose.
Two New Serological Groups of
Actinomyces
Authors: Slack John M. , Gerencser Mary Ann
Published: January 2020

Actinomyces odontolyticus
and
A. viscosus
are designated as group E and group F in the serological grouping of the
Actinomyces
.
Cell Wall Polymers of
Bacillus sphaericus
9602 II. Synthesis of the First Enzyme Unique to Cortex Synthesis During Sporulation
Authors: Tipper Donald J. , Pratt Iona
Published: January 2020

The cell wall peptidoglycan of vegetative cells of
Bacillus sphaericus
9602 contains
l
-lysine and
d
-isoasparagine and is devoid of diaminopimelic acid (Dap), whereas the peptidoglycan of its spore cortex is devoid of
l
-lysine and
d
-isoasparagine and contains
meso
-Dap. These two structures have a common biosynthetic precursor, uridine-diphospho-
N
-acetylmuramyl-
l
- alanyl-
d
-glutamic acid, which accepts either
l
-lysine or
meso
-Dap, the latter reaction being the first unique to the synthesis of the spore cortex peptidoglycan.
l
-lysine-adding activity decays at the end of vegetative growth to a level which is maintained until Dap-adding activity appears, when it declines rapidly again. Dap-adding activity is not detectable in refractile spores, in vegetative cells, or in sporulating cells until about 4 hr after the end of vegetative growth, when it increases rapidly for about 1.5 hr in a process dependent on continued protein and ribonucleic acid (RNA) synthesis. This process apparently involves transcription and translation during this period of a “sporulation-specific” gene whose product is essential for and unique to sporulation. It is closely followed by the acquirement of refractility. Another sporulation-specific gene, that for dipicolinate synthase, is apparently transcribed and translated in an overlapping period commencing about 0.5 hr later, although dipicolinate does not accumulate rapidly until 1.5 hr later, when about 75% of the cells are already refractile. Inhibition of protein synthesis with chloramphenicol or of RNA synthesis with streptolydigin inhibited accumulation of these enzymes in sporulating cells; this inhibition could be reversed by washing out the antibiotics after 1.5 hr. Sporulation recommenced with an unaltered sequence of events but with poorer synchrony. There was no evidence for a messenger RNA for either enzyme of lifetime greater than a small fraction of the period of enzyme accumulation, although dilution with 10 volumes of fresh medium failed to prevent synthesis of Dap-adding enzyme in cells which had become terminally swollen, a process preceding enzyme synthesis by about 1.5 hr. The synthesis of this enzyme in
B. sphaericus
is apparently dependent on programmed transcription of the appropriate gene.
Induction of Kynureninase in
Neurospora
Authors: Turner J. R. , Sorsoli W. A. , Matchett W. H.
Published: January 2020

Induction of kynureninase in a homogeneous population of mycelia in balanced growth was studied. Induced synthesis of enzyme was apparent 10 min after addition of inducers (tryptophan, kynurenine, and
N
-formylkynurenine). Experiments with cycloheximide-inhibited cells indicated that initiation of message transcription occurred about 4 min after addition of inducers. Lifetime of the message in the absence of inducer was of the order of 5 min. Experiments with mutants showed that
N
-formylkynurenine was the probable inducer of physiological importance.
Fatty Acid Distribution in Mesophilic and Thermophilic Strains of the Genus
Bacillus
Authors: Shen P. Y. , Coles E. , Foote J. L. , Stenesh J.
Published: January 2020

The fatty acid distribution of three mesophilic and three thermophilic strains of the genus
Bacillus
was determined by gas chromatography of the fatty acid methyl esters. Fatty acid i-15:0 was the most abundant in both the mesophiles (51%) and the thermophiles (41%). The second most abundant fatty acid was a-15:0 in the mesophiles (22%), and i-17:0 in the thermophiles (27%). The fatty acid pair i-15:0, i-17:0 was the most predominant pair in both the mesophiles (61%) and the thermophiles (66%). The fatty acid pair a-15:0, a-17:0 was the second most predominant pair and was much higher in the mesophiles (30%) than in the thermophiles (15%). The average fatty acid chain length was 15.5 for the mesophiles and 16.0 for the thermophiles. The significance of these results for the lipid theory of thermophily is discussed.
Isolation of a Nonpigmented, Thermophilic Bacterium Similar to
Thermus aquaticus
Authors: Ramaley Robert F. , Hixson Jane
Published: January 2020

A thermophilic (70 C), gram-negative bacterium has been isolated that resembles
Thermus aquaticus
but lacks the type-characteristic yellow carotenoid.
Electrophoretic Analysis of Cell Proteins of T-Strain Mycoplasmas Isolated from Man
Authors: Razin S. , Valdesuso J. , Purcell R. H. , Chanock R. M.
Published: January 2020

Electrophoretic patterns of the cell proteins of 12 T-strain mycoplasmas isolated from man showed a remarkable similarity. This finding suggests that these strains are genetically closely related and supports their classification in a single species.
Isolation and Identification of Echinenone from
Micrococcus roseus
Authors: Schwartzel E. H. , Cooney J. J.
Published: January 2020

An orange carotenoid from
Micrococcus roseus
was purified by solvent partitioning followed by column and thin-layer chromatography. Absorption spectra, chromatographic mobility, and partition coefficient suggested that the pigment was echinenone (4-keto-β-carotene). Reduction yielded a pigment with the spectral and polar properties of isocryptoxanthin (4-hydroxy-β-carotene), the expected product. The orange pigment and its reduction product co-chromatographed with the respective authentic pigments, confirming the original pigment as echinenone. To our knowledge echinenone has not been identified previously as a bacterial pigment.
Ribonucleic Acid Synthesis During Microcyst Formation in
Myxococcus xanthus
: Characterization by Deoxyribonucleic Acid-Ribonucleic Acid Hybridization
Authors: Okano Paul , Bacon Karen , Rosenberg Eugene
Published: January 2020

The technique of deoxyribonucleic acid-ribonucleic acid (RNA) hybridization was used to compare the RNA synthesized during vegetative growth and microcyst formation in
Myxococcus xanthus
. All classes of RNA, including ribosomal RNA, were synthesized during microcyst formation. The results indicate that the ribosomal RNA synthesized during microcyst formation was indistinguishable from that made during vegetative growth. Hybridization competition experiments demonstrated that certain messenger RNA species are synthesized only during vegetative growth, whereas others are synthesized only during microcyst formation. The synthesis of a new species of RNA polymerase does not appear to be responsible for differential transcription during morphogenesis in
M. xanthus
since the rifampicin sensitivity of transcription was conserved during microcyst formation.
Morphogenesis of Cysts in
Azotobacter vinelandii
Authors: Hitchins Victoria M. , Sadoff Harold L.
Published: January 2020

Cultures of
Azotobacter vinelandii
were induced to encystment with β-hydroxybutyrate. The morphological events in the transition from cell to cyst were observed by electron microscopy of thin sections. Upon induction of encystment, cells became rounded and nonmotile. The exine coat developed by the continuous excretion of membranous components into the capsule surrounding the cell.
Properties of the Amylase from
Halobacterium halobium
Authors: Good Wendy A. , Hartman Paul A.
Published: January 2020

Halobacterium halobium
amylase had optimal activity at
p
H 6.4 to 6.6 in sodium β-glycerophosphate buffer containing 0.05% NaCl at 55 C; Ca
2+
was not required. End products from amylose were maltose, maltotriose, and glucose. The amylase, which was devoid of transglucosylase activity, had a multichain attack mechanism.
Glycogen Metabolism in Chlamydia-Infected HeLa-Cells
Authors: Fan Victor S. C. , Jenkin Howard M.
Published: January 2020

A difference in glycogen metabolism between two strains of
Chlamydia
agents was observed which can serve as a taxonomic marker to distinguish
C. psittaci
from
C. trachomatis
.
Citric Acid Cycle: Gene-Enzyme Relationships inBacillus subtilis
Authors: Rutberg Blanka , Hoch James A.
Published: January 2020

The genetic location of mutations affecting the citric acid cycle and the properties of mutants ofBacillus subtilispossessing these mutations have been examined. Genes coding for the component enzymes of the cycle were found to be unlinked to each other and thus do not form an operon. The mutational defect in a mutant lacking fumarase mapped betweenthr-5andcysB3. Mutations causing inability to produce isocitrate dehydrogenase and succinate dehydrogenase were found to map betweenargA11andleu-1. The α-ketoglutarate dehydrogenase mutations were mapped at the terminal end of theB. subtilischromosome through a weak linkage in phage PBS-1 transduction of one class of these mutations ofilvA2andmetB4. A second class of α-ketoglutarate dehydrogenase mutations mapped closer toilvA2andmetB4but still terminal with respect to these markers. Aconitaseless mutants possessed mutations that could not be linked to any of the known transducing segments of the chromosome. An effect of mutation conferring loss of one enzyme of the cycle on the specific activity of the other enzymes in the cycle was observed.
Isolation and Properties of a β-Alanine Transaminaseless Mutant ofPseudomonas fluorescens
Authors: Hechtman P. , Scriver C. R. , Middleton R. B.
Published: January 2020

β-Alanine catabolism inPseudomonas fluorescensis initiated by the enzyme β-alanine transaminase. We have isolated mutants which fail to produce this enzyme and thus cannot grow on β-alanine as the sole nitrogen source. The accumulation of β-alanine-1-14Chas been studied in one of these mutants, strain 67, and in the wild type. In the mutant, β-alanine remains in a stable intracellular pool, whereas in the wild type conversion of β-alanine to an intermediate, presumably malonate semialdehyde, and to CO2can be detected. The membrane transport system for β-alanine can be conveniently studied in this transaminaseless mutant.
Induction, Morphogenesis, and Germination of the Chlamydospore of
Candida albicans
Authors: Jansons Vilma K. , Nickerson Walter J.
Published: January 2020

Early log phase yeast cells of
Candida albicans
transformed into suspensor cells and chlamydospores when streaked on washed agar without added nutrients. The transformation was apparently a result of endogenous metabolism since starved yeast cells did not form chlamydospores. Addition of glucose (5 mg/ml) to washed agar completely suppressed chlamydospore formation. Size of inoculum and age of inoculum markedly affected chlamydospore yield. Electron microscopy of thin sections revealed the chlamydospore wall to be double layered, the outer thin layer being continuous with the wall of the suspensor cell. A technique was devised to study germination of chlamydospores. Chlamydospores germinated by budding, and the fluorescent antibody technique was used to study the budding process.
Action of Penicillin G on Endosymbiote
Lambda
Particles of
Paramecium aurelia
Authors: Soldo Anthony T. , Musil George , Godoy Gustavo A.
Published: January 2020

The kinetics of loss from the cytoplasm and changes in ultrastructure of symbiont
lambda
particles after treatment of axenically cultivated
lambda
-bearing
Paramecium aurelia
with penicillin G was investigated. Low concentrations (1 to 2 unit/ml) of the antibiotic caused many particles within the cell to become filamentous; high concentrations (2,000 unit/ml) caused lysis of the particles without noticeably affecting the protozoan. The ED
50
value (2 to 3 unit/ml) was within the range of values found to cause lysis of many gram-negative bacteria. Rapidly dividing
lambda
were more vulnerable to the action of the antibiotic than slowly dividing particles. Nondividing particles were not affected by exposure to the antibiotic. Ultrastructural changes observed in
lambda
during lysis by penicillin G were consistent with the view that penicillin interferes with the synthesis of a vital component of the cell envelope of the particle, possibly a peptidoglycan similar to that found in the cell walls of bacteria. The deoxyribonucleic acid of
lambda
was dispersed throughout the particle as electron dense fibers enclosed within electron transparent areas. The cell envelope appeared to consist of at least two morphologically distinguishable layers, an inner layer homologous to the plasma membrane of bacteria and an outer layer homologous to the bacterial cell wall.
Lambda
may be regarded as a randomly distributed population of bacteria growing and dividing synchronously within the collective cytoplasm of its protozoan host.
Paraffin Oxidation in
Pseudomonas aeruginosa
II. Gross Fractionation of the Enzyme System into Soluble and Particulate Components
Authors: Van Eyk J. , Bartels T. J.
Published: January 2020

Osmoplast production in
Pseudomonas aeruginosa
was investigated to obtain osmotically sensitive cells for studies on the subcellular location of the paraffin-oxidizing enzyme system. It proved possible to convert cells of
P. aeruginosa
treated with lysozyme and ethylenediaminetetraacetic acid in tris(hydroxymethyl)aminomethane-sucrose buffer (
p
H 8) into osmotically sensitive cells within 2 min. Active, cell-free preparations were obtained by the subsequent osmotic disruption in the presence of deoxyribonuclease and magnesium chloride. The conditions necessary for a complete separation of membranes and soluble cell constituents were established by following the distribution of two reference enzymes. An enzyme assay based on direct gas chromatographic analysis of the oxidation products from
n
-heptane is described for the paraffin-oxidizing enzyme system. By using this method, we investigated the enzymatic organization and subcellular distribution of the paraffin-oxidizing enzyme system. It was confirmed that the enzyme system is composed of three components, each of which is indispensable for the hydroxylation of
n
-heptane. One of these components, the hydroxylase, was located in two cell fractions; the other two components occur exclusively in the soluble cell fraction. The half-life of a crude enzyme preparation kept at ambient temperature is approximately 3.5 hr. This poor stability was found to be primarily due to the instability of one of the soluble factors, presumably the reduced nicotinamide adenine dinucleotide-rubredoxin reductase.
Transduction of Methicillin Resistance in
Staphylococcus aureus
Dependent on an Unusual Specificity of the Recipient Strain
Authors: Cohen Sidney , Sweeney Helen M.
Published: January 2020

Resistance to methicillin was transduced by phage 80 or 53 from two naturally occurring methicillin-resistant strains of
Staphylococcus aureus
to methicillin-susceptible recipient strains at frequencies of 10
−7
to 10
−9
. Ultraviolet irradiation of transducing phage and posttransductional incubation at 30 C were essential for useful frequencies of transduction. Effectiveness as a recipient for this transduction was highly specific. Strain NCTC 8325 (PS47) in its native state was an ineffective recipient but became effective after it had received by transduction one of several penicillinase plasmids. This acquired effectiveness was retained in most cases after elimination of the plasmid by ethidium bromide treatment. Like the donor strain, the progeny were heterogeneous in the degree of their resistance to methicillin, which was expressed by a higher proportion of cells as the temperature of incubation was lowered from 37 to 30 C. Separate transductants varied widely in the degree of resistance acquired by transduction. Methicillin resistance was stable in the donor and transductant strains. We favored the interpretation that methicillin resistance in our strains was determined by a single chromosomal gene, although the possibility that it was determined by two or more closely linked genes could not be excluded.
Electron Microscopic Observations on the Fine Structure of Cell Walls of
Chlamydia psittaci
Authors: Matsumoto Akira , Manire G. P.
Published: January 2020

L-cell cultures were infected with elementary bodies (EB) of meningopneumonitis organisms. Cell walls were prepared from reticulate bodies (RB), which are the intracellular developmental forms into which EB are converted, and from EB at appropriate times after infection. When fragmented EB cell walls were shadowcast with platinum palladium alloy, about one-half of the fragments were seen to be composed of hexagonally arrayed structures on the inner side of the cell wall. When EB cell walls were negatively stained with phosphotungstic acid, they all showed this fine structural array. These macromolecular units were estimated to be about 18 nm in diameter. RB cell walls, harvested at various times after infection, were similarly stained; about 20% of RB walls at 15 hr after infection showed traces of these regular structures, but only 2% of them had the structures at 24 hr. When RB cell walls prepared from penicillin-containing culture were examined, they were observed to be similar to RB without penicillin. When EB cell walls were treated with formamide at 160 C, and then centrifuged in a 10 to 40% potassium tartrate density gradient, hexagonal particles about 20 nm in diameter were obtained as a middle band in the gradient column. These particles were not obtained from RB cell walls harvested from cultures with or without penicillin. It is concluded that the particles are macromolecular subunits located on the inner side of the EB cell walls, that the subunits probably provide the structural rigidity found in the EB, and that their synthesis is inhibited by penicillin.
Production and Repair of Radiochemical Damage in
Escherichia coli
Deoxyribonucleic Acid; Its Modification by Culture Conditions and Relation to Survival
Authors: Town Christopher D. , Smith Kendric C. , Kaplan Henry S.
Published: January 2020

Late log-phase
Escherichia coli
B/r cells are 1.6 times more sensitive to killing by X rays than are stationary-phase cells when grown in Brain Heart Infusion (BHI) + glucose. The number of single-chain breaks formed per krad is the same for log- and stationary-phase cells. Stationary-phase cells show a somewhat greater ability to repair single-chain breaks (especially after high doses of X rays) than do log-phase cells. The rapidity and extent of postirradiation deoxyribonucleic acid (DNA) degradation are greater in log-phase cells than in stationary-phase cells. The enhanced viability exhibited by stationary-phase cells thus appears to correlate both with enhanced single-chain break repair and the reduced degradation of DNA. Cells grown to stationary phase in peptone medium (PO cells) are 3.4 times more sensitive to killing by X rays than cells grown to stationary phase in peptone medium supplemented with glucose and phosphate buffer (PG cells). The yield of single-strand breaks is the same for both types of cells (but the absolute yield is about two times higher than in the cells grown in BHI + glucose). The kinetics for the repair of single-chain breaks are the same for both types of cells for about 30 min. After this time period, further repair ceases in the PO cells but continues in the PG cells, provided that glucose is present in the medium. Postirradiation DNA degradation is both more rapid and more extensive in PO cells than in PG cells whether or not glucose is present in the postirradiation incubation medium. The survival of stationary-phase
E. coli
B/r grown in PO or PG medium is likewise unaffected by the presence of glucose in the plating medium, and thus correlates better with the lower DNA degradation seen in the PG cells than with the increased strand rejoining, since this latter process requires the presence of glucose.
Sporulation of a Cortexless Mutant of a Variant of
Bacillus cereus
Authors: Pearce Susanne M. , Fitz-James Philip C.
Published: January 2020

A stage 4 sporulation mutant of a strain of
Bacillus cereus
var.
alesti
fails to synthesize a cortex although all other structural components appear normal. With terminal lysis the spore core as well as the sporangium is lysed. Both the uptake of
45
Ca and the synthesis of dipicolinic acid (DPA) are similar to these activities in the parent strain, but these components (DPA and Ca) are lost to the medium with the drastic lysis. The first stage of diaminopimelic acid incorporation, that into germ cell wall mucopeptide, is intact in the mutant; the second stage, that into cortical mucopeptide, is absent. These biochemical studies as well as phospholipid metabolism and freeze-etch analysis suggest the lesion lies in the outer forespore membrane.
Immunological Properties of
Micrococcus lysodeikticus
Membranes
Authors: Fukui Yoshio , Nachbar Martin S. , Salton M. R. J.
Published: January 2020

Membranes of
Micrococcus lysodeikticus
possess antigens which are distinct from other cellular components such as cytoplasm, ribosomes, and cell walls. Only a few (two to three) components are found when dissociated membranes are examined by immunodiffusion and immunoelectrophoresis techniques. Membranes treated with 0.3% sodium dodecyl sulfate, 0.3% Triton X-100, trypsin, phospholipase A or C, or by sonic oscillation at
p
H 9.0, all showed the same pattern (three major bands) when examined against membrane antisera by immunoelectrophoresis. Immunological analysis of fractions isolated by sucrose gradient centrifugation or by polyacrylamide gel electrophoresis suggests that individual components cross-react. Antibodies to adenosine triphosphatase (EC 3.6.1.3) and fast-moving component are not removed by absorption with protoplasts. Removal of antibody to one of the membrane antigens by protoplast absorption indicated a surface location. Glutaraldehyde fixation of protoplasts resulted in the loss of membrane antigens detectable by immunodiffusion.
Control of Cell Growth in Bacteria: Experiments with Thymine Starvation
Authors: Kubitschek H. E.
Published: January 2020

When cells of
Escherichia coli
THU were starved for thymine, they continued to grow without division for at least two successive volume doublings at their initial rate. Within experimental error this average rate of volume increase, 0.21 μm
3
per hr, was identical with that observed in control cultures during two generations of growth in the presence of thymine. This growth rate was also independent of the age of the cells at the time of starvation. These results are consistent with the hypothesis, proposed earlier, that growth rates are controlled by uptake sites for binding, transport, or accumulation of compounds into the cell, that the number of these sites is constant throughout most of the cell cycle, and that this number doubles near or at cell division.
Nature of Ribosome-Bound β-Galactosidase
Authors: Bronskill Patricia M. , Wong J. Tze-Fei
Published: January 2020

Properties of the ribosome-bound β-galactosidase were examined in
Escherichia coli
cells after prolonged induction. This fraction of enzyme was not chased from ribosomes by removal of inducer, or by treatments with hydroxylamine, puromycin, chloramphenicol, and azide. However, the metabolic turnover of this fraction could be demonstrated by means of a pulsed exposure to the phenylalanine analogue β-2-thienylalanine, and this fraction was enriched in heavy forms relative to the soluble enzyme. These observations indicated a tight coupling of the release of ribosome-bound enzyme to nascent enzyme synthesis, and it is suggested that the ribosome-bound enzyme is related to an intermediate stage in the assembly of quarternary enzyme structures.
Genetic Analysis of Lysine Auxotrophs of
Staphylococcus aureus
Authors: Barnes Isabel J. , Bondi Amedeo , Fuscaldo Kathryn E.
Published: January 2020

The genetics of lysine biosynthesis in
Staphylococcus aureus
was examined by a transductional analysis of lysine auxotrophs. These mutants had previously been grouped according to their biochemical characteristics. The mutant sites appeared to be closely linked. Complementation was observed between different groups but not between mutant strains belonging to the same group. A strain was detected which seemed to have a mutant control region. Evidence is presented to support the hypothesis that the lysine biosynthetic region functions as an operon.
Induction of Hemolysin Synthesis by Transformation in
Staphylococcus aureus
Authors: Nomura Hiroko , Udou Takezo , Yoshida Kosaku , Ichikawa Yoichi , Naito Yoshiko , Smith Melvin R.
Published: January 2020

A nonhemolytic strain of
Staphylococcus aureus
was transformed with deoxyribonucleic acid extracted from two hemolytic strains of
S. aureus
. In each case the hemolysin pattern after transformation was identical to that of the donor strain. However, bacteriophage type, serotypes, and other biological properties of the recipient strain remained unaffected.
Properties of Aldolase from
Francisella tularensis
Authors: Beck Raymond W. , Schawel Kenneth W.
Published: January 2020

The aldolase of
Francisella tularensis
resembles Class II aldolases in its requirement for divalent ions and its inactivation by metal chelating agents. Cysteine and other reducing agents stimulated the activity of the enzyme.
Formation of Tumor-Like Structures on Legume Roots by
Rhizobium
Authors: MacGregor A. N. , Alexander M.
Published: January 2020

Tumor-like structures appeared on the roots of
Medicago sativa, Alysicarpus vaginalis
, and
Trifolium pratense
inoculated with a non-nodulating strain of
Rhizobium trifolii
or with irradiated cultures of either of two nodulating
Rhizobium
strains. The structures were composed of disorganized plant tissues which, on the basis of microscopic examination, were devoid of bacterial cells. Rhizobia which could nodulate legumes of one cross-inoculation group and which were able to induce formation of such tumor-like structures on plants of a second cross-inoculation group were isolated from extracts of these root growths. The apparent tumorogenic activity of some of the rhizobia, but not their nodulating capacity, was lost when the bacteria were transferred in laboratory media.
Biosynthesis of Biotin: Synthesis of 7,8-Diaminopelargonic Acid in Cell-Free Extracts of
Escherichia coli
Authors: Pai C. H.
Published: January 2020

Cell-free extracts prepared from a biotin auxotroph of
Escherichia coli
were active in catalyzing the synthesis of 7,8-diaminopelargonic acid, an intermediate of the biotin pathway, from 7-oxo-8-aminopelargonic acid. The product was identified on the basis of its chromatographic characteristics and its biotin activities for biotin auxotrophs of
E. coli
. Enzyme activity was determined in a reaction coupled with the desthiobiotin synthetase system, which is required for the conversion of 7,8-diaminopelargonic acid to desthiobiotin, and by measuring the amount of desthiobiotin formed by microbiological assay. The reaction was stimulated by
l
-methionine and pyridoxal-5′-phosphate.
l
-Methionine could not be replaced by any other amino acids tested. Pyridoxamine and pyridoxamine-5′-phosphate were as active as pyridoxal phosphate. The enzyme, presumably an aminotransferase, was demonstrable in the parent strain of
E. coli
and all mutant strains tested with the exception of a strain which is able to grow on diaminopelargonic acid but not on 7-oxo-8-aminopelargonic acid. Furthermore, the enzyme was repressible by biotin. The results were consistent with the hypothesis that the biosynthesis of 7,8-diaminopelargonic acid from 7-oxo-8-aminopelargonic acid is an obligatory step in the biosynthetic pathway of biotin in
E. coli
.
Appearance of a New Species of Ribonucleic Acid During Sporulation in
Saccharomyces cerevisiae
Authors: Kadowaki Kiyoshi , Halvorson H. O.
Published: January 2020

In the course of study on ribonucleic acid (RNA) metabolism during sporulation in
Saccharomyces cerevisiae
, a new species of RNA (20
S
) was observed in sporulating cells by polyacrylamide gel electrophoresis. The relative content of this RNA to total RNA increased linearly early in sporulation. Labeled adenine was preferentially incorporated into 20
S
RNA during the early stages of sporulation. The correlation between the physiological and genetic control of sporulation and the synthesis of 20
S
RNA are discussed.
Genetic Recombination in
Streptomyces bikiniensis
var.
zorbonensis
Authors: Coats John H. , Roeser Joanne
Published: January 2020

A genetic recombination system in
Streptomyces bikiniensis
var.
zorbonensis
is described. This strain produces a mixture of antibiotics including zorbamycin and zorbonomycin B and C. A genetic map has been constructed from data obtained from an analysis of haploid recombinants which shows linkage relationships of 17 marker loci. Determination of map location has been made for three different loci affecting antibiotic biosynthesis in this strain.
Use of Antibody to Membrane Adenosine Triphosphatase in the Study of Bacterial Relationships
Authors: Whiteside Theresa L. , De Siervo August J. , Salton Milton R. J.
Published: January 2020

An antiserum to Ca2+-activated adenosine triphosphatase from membranes ofMicrococcus lysodeikticuscross-reacted in agar gels with membrane adenosine triphosphatases from other pigmented micrococci and related species. Species ofMicrococcusandSarcinashowed different levels of inhibition of adenosine triphosphatase activities in heterologous reactions with antiserum. Inter- and intraspecific relationships based on the inhibition reaction were compared with an independent parameter, namely the quantitative and qualitative composition of the bacterial membrane phospholipids and fatty acids. The guanine plus cytosine contents in the deoxyribonucleic acid of the species studied correlated well with the serological cross-reactivity of adenosine triphosphatases from their membranes. The types of cross-bridges found in the peptidoglycans of these cocci were also compared with the other properties. The results suggest that an antiserum specific for a major membrane protein may be a reliable and most useful adjunct in studying bacterial serotaxonomy.