bluuebunny/crossref_metadata_2025 huggingface dataset:
Antigens of
Streptococcus mutans
II. Characterization of an Antigen Resembling a Glycerol Teichoic Acid in Walls of Strain BHT
Authors: Vaught Richard M. , Bleiweis A. S.
Published: January 2020

Cold 10% trichloroacetic acid was used to extract antigens from purified cell walls of
Streptococcus mutans
BHT. Column chromatography on Biogel P-100 resolved two serologically reactive fractions (B and C). These fractions were ascertained to be relatively pure by recycling on Biogel P-100, Ouchterlony double-diffusion analysis, and immunoelectrophoresis. Fractions B and C demonstrated bands of absolute homology by double-diffusion but different mobilities by immunoelectrophoresis. Chemical analysis indicated that fraction B is a polysaccharide composed principally of rhamnose and galactose, with smaller amounts of glucose and glucosamine. Small quantities of glycerol and phosphorus also were found. Fraction C was composed mainly of galactose, glycerol, and phosphorus. Alkaline hydrolysis of this fraction yielded products typically released by the degradation of a glycerol teichoic acid, such as glycerol monophosphate, glycerol diphosphate, inorganic phosphorus, and several glycosyl glycerol phosphates. Diglycerol triphosphate was not detected. Side-group analysis revealed that glycerol was substituted by mono- and trigalactosyl moieties. Fraction C was deduced to contain 25 glycerol phosphate units per polymer length. Hapten inhibition studies revealed a β-galactoside as the probable hapten on this antigen. The BHT teichoic acid reacted strongly with FA-1 antiserum. It showed bands of homology with both BHT and FA-1 crude acid extracts upon double-diffusion, using antisera to either strain. The BHT teichoic acid also displayed immunoelectrophoretic behavior identical to one of the mobile FA-1 cell wall antigens, again using either serum to develop precipitin bands. It is concluded this antigen may possess a serotype-specific determinant for
S. mutans
serotype
b
.
Epidemiological and Biochemical Studies on Thiamine-less Dwarf-Colony Variants of
Staphylococcus aureus
as Etiological Agents of Bovine Mastitis
Authors: Sompolinsky David , Cohen Miriam , Ziv Gideon
Published: January 2020

Dwarf-colony (D) variants of
Staphylococcus aureus
are relatively widespread etiological agents of bovine mastitis in Israel. D strains grow on ordinary solid nutrient media with pinpoint, transparent colonies. An epidemiological study indicated that these variants are more communicable than normal (N)
S. aureus
strains. Biochemically, several types of metabolic defects have been demonstrated among the D strains: strains from one herd were pantothenate-less, most of the other isolates were thiamine-less, and a few of them were both thiamine-and pantothenate-less. Among the thiamineauxotrophs were a few (from one herd) which were unable to concentrate thiamine-thiazole, whereas all of the other strains required thiamine-pyrimidine (HMP) in the form of pyrophosphate (HMP-PP). At least some of these D strains were defective in three functions: concentrative uptake of HMP, phosphorylation of HMP, and phosphorylation of HMP-monophosphate. Since mutants with normal growth occurred readily, we assumed that the information for these three functions exists on a polycistronic operon. Quantitative requirements for HMP-PP varied highly among the D strains, and other data also indicated that HMP-PP-requiring strains had not developed from a common source.
Liver Abscess Production by Non-Spore-Forming Anaerobic Bacteria in a Mouse Model
Authors: Hill Gale B. , Osterhout Suydam , Pratt Phillip C.
Published: January 2020

A model anaerobic infection consisting of progressive intrahepatic abscesses was produced in mice by injection of single and combined species of non-spore-forming anaerobic bacteria.
Detection of Tumor-Specific Antigens in an Equine Sarcoid Cell Line
Authors: Watson R. E. , Larson K. A.
Published: January 2020

Indirect immunofluorescence and lymphocyte cytotoxicity experiments demonstrated the presence of a tumor-specific antigen(s) on the surface of cells from an equine sarcoid cell line (Mc1). Autologous serum (taken from the horse from which the Mc1 cells were derived) and sera from three other sarcoid-bearing horses revealed a similar membrane immunofluorescence when reacted with Mc1 cells, indicating the existence of cross-reacting antibodies. Results of serum colony inhibition experiments indicate that these antibodies are not cytotoxic. Incubation of Mc1 cells with autologous lymphocytes resulted in a toxicity to Mc1 cells, thereby demonstrating a cell-mediated immune reaction to autologous tumor cells.
Biosynthesis of Cell Wall Lipopolysaccharide in Mutants of
Salmonella
V. A Mutant of
Salmonella typhimurium
Defective in the Synthesis of Cytidine Diphosphoabequose
Authors: Yuasa Ryosuke , Levinthal Mark , Nikaido Hiroshi
Published: January 2020

A mutant of
Salmonella typhimurium
LT2 was found to be unable to convert cytidine diphospho-4-keto-6-deoxy-
d
-glucose into cytidine diphosphoabequose. The mutation maps in the
rfb
gene cluster, which is known to be involved in the biosynthesis of the peripheral, “O side-chain” portion of cell wall lipopolysaccharide. In spite of the fact that, in the O side chains, abequose is not a part of the main chain but occurs as short branches, the mutant appears to be unable to polymerize oligosaccharide “repeat units” into long O side chains. The following evidence indicates that this failure is the result of the absence of cytidine diphosphoabequose rather than that of a superimposed second mutation in other genes of the
rfb
cluster. (i) The mutant does not behave like a multisite mutant in genetic crosses, and it gives rise, at a high frequency, to “revertants” where the ability to synthesize cytidine diphosphoabequose and the ability to synthesize normal lipopolysaccharide with O side chains are both restored. (ii) The mutant strain has normal levels of activity of all of the other enzymes known to be involved in O side-chain synthesis, except that the levels of several enzymes were lowered by about 30% owing to the polarity effect of the mutation. That the lowering of these enzymes is not responsible for the failure of the mutant to synthesize O side chains is clear from the fact that there were revertants which had regained some ability to synthesize abequose but still had lowered levels of these other enzymes, and that this type of revertant produced lipopolysaccharide with considerable amounts of O side chains.
Enhanced Growth of T-Strain Mycoplasmas with
N
-2-Hydroxyethylpiperazine-
N′
-2-Ethanesulfonic Acid Buffer
Authors: Manchee Richard J. , Taylor-Robinson David
Published: January 2020

The small size of T-strain mycoplasma colonies obtained on agar medium has been a drawback to the study of these organisms. The incorporation of 0.05
m
N
-2-hydroxyethylpiperazine-
N′
-2-ethanesulfonic acid (HEPES), a new hydrogen ion buffer, into agar medium at
p
H 6.8 led to the production of colonies at least 60% greater in diameter than those obtained on media without HEPES at
p
H 6.5 or 6.0. In addition, the colonies often had the “fried-egg” appearance typical of “classical” large-colony-forming mycoplasmas. The addition of HEPES to liquid medium in the presence of 0.1% urea resulted in a slightly higher number of viable organisms and a corresponding increase in ammonia production. Rapid death of the mycoplasmas occurred on continued incubation of the liquid medium cultures even in the presence of HEPES. The larger colony size facilitated the study of hemadsorption and tissue-culture cell adsorption. Preliminary results of such tests in which these phenomena have been demonstrated are presented. The advantages and disadvantages of having larger colonies are discussed, and the terminology of T-strain mycoplasmas is considered in the light of the present findings.
Characteristics of Virulent, Attenuated, and AvirulentMycoplasma pneumoniaeStrains
Authors: Lipman Richard P. , Clyde Wallace A. , Denny Floyd W.
Published: January 2020

Homologous pairs of virulent and attenuated or avirulentMycoplasma pneumoniaestrains were derived and compared in an effort to elucidate the mechanisms of virulence. These related strains were found to vary in growth, glycolysis, protein electrophoretic patterns, peroxide formation, morphology, and cytadsorption. Variations in the last two characteristics closely correlated with avirulence. This enables understanding of one stage in the pathogenic sequence and provides a convenient marker for avirulence. The derivation of infectious avirulent strains may make possible their use as live vaccines againstM. pneumoniaedisease.
Chromosomal Location of a Gene for Fructose 6-Phosphate Kinase in
Escherichia coli
Authors: Morrissey A. T. E. , Fraenkel D. G.
Published: January 2020

Pfk
lies between
rha
and
glpK
.
Aminoglycoside Antibiotics: Inactivation by Phosphorylation inEscherichia coliCarrying R Factors
Authors: Ozanne B. , Benveniste R. , Tipper D. , Davies J.
Published: January 2020

R-factor strains which are streptomycin-resistant and spectinomycin-sensitive have been found to inactivate streptomycin by a new mechanism. The 3′-OH group of the 2-deoxy-2-methylamino-l-glucopyranosyl moiety is phosphorylated.
Immunity to Staphylococcal Infection in Mice: Effect of Living Versus Killed Vaccine, Role of Circulating Antibody, and Induction of Protection-Inducing Antigen(s) In Vitro
Authors: Ekstedt Richard D. , Yoshida Kosaku
Published: January 2020

Mice immunized by sublethal doses of livingStaphylococcus aureusstrains other than the Smith diffuse strain were significantly more resistant to challenge with the Smith diffuse strain than animals immunized with heat-killed organisms. The increased resistance observed was shown, by appropriate passive protection experiments with immune mouse sera, to be due to circulating antibody, probably of the IgM class. In addition, it was observed that strains ofS. aureusother than the Smith diffuse strain, when cultured in a modified Staphylococcus 110 broth but not in Brain Heart Infusion, were capable of absorbing protective antibody from hyperimmune rabbit antiserum.
Evidence Against Necessary Phosphorylation During Hexose Transport in
Aspergillus nidulans
Authors: Brown Candice E. , Romano Antonio H.
Published: January 2020

The transport of 2-deoxy-
d
-glucose, a nonmetabolizable glucose analogue, into
Aspergillus nidulans
against a concentration gradient does not appear to require phosphorylation, despite the high levels of sugar phosphates accumulated rapidly within the cell. Two other deoxy analogues of
d
-glucose, 6-deoxy-
d
-glucose and 1,5-anhydro-
d
-glucitol (1-deoxy-
d
-glucose), although they lack the C-6 and the C-1 hydroxyl groups, respectively, and thus cannot be phosphorylated in those positions, still competitively inhibit the entry of 2-deoxy-
d
-glucose. Moreover, 6-deoxy-
d
-glucose can be concentrated against a gradient within the cell without the accumulation of 6-deoxy-
d
-glucose-phosphate.
d
-Galactose shows an intracellular ratio of free to phosphorylated sugar similar to that found for 2-deoxy-
d
-glucose in cells that have galactokinase, but no sugar phosphates are found in a galactokinaseless mutant strain. These data suggest that intracellular kinases are responsible for the sugar phosphate pool; and indeed, a kinase capable of phosphorylating 2-deoxy-
d
-glucose has been demonstrated. Finally, experiments on the kinetics of labeling of intracellular free sugar and sugar phosphate pools with
14
C-2-deoxy-
d
-glucose show that radioactivity appears first in the free sugar pool and after a delay enters the sugar phosphate pool.
Protoplasts Obtained from
Candida tropicalis
Grown on Alkanes
Authors: Lebeault J. M. , Roche B. , Duvnjak Z. , Azoulay E.
Published: January 2020

A method for the preparation of protoplasts from
Candida tropicalis
cultivated on
n
-tetradecane is described. This essentially consists of replacing the mannitol-sorbitol solution of the classical helicase technique by 1
m
magnesium sulfate and lowering the
p
H to 4.1 during incubation in the presence of helicase. The protoplasts thus prepared behave like intact cells and are capable of consuming oxygen in the presence of
n
-tetradecane,
n
-decane, 1-decanol, and glucose.
Electron Microscopy of Small Cells:
Mycoplasma hominis
Authors: Maniloff Jack
Published: January 2020

The size, ultrastructure, and reproduction of
Mycoplasma hominis
species H39 were studied by electron microscopy. These are the smallest known cells.
Partial Purification and Characterization of Dihydrodipicolinic Acid Synthetase from Sporulating
Bacillus megaterium
Authors: Webster Francis H. , Lechowich Richard V.
Published: January 2020

Sporulation of
Bacillus megaterium
Km (ATCC 13632) was synchronized by a technique employing three 10% transfers. The culture was harvested when 60% of the cells contained spore forms. Dihydrodipicolinic acid synthetase was purified 150-fold by ammonium sulfate fractionation at
p
H 6.5, heating for 15 min at 45 C at
p
H 6.0, ammonium sulfate fractionation at
p
H 6.0, and subsequent chromatography on diethylaminoethyl cellulose. During the final stage of the purification procedure, the enzyme exhibited sensitivity to refrigeration temperatures. The enzyme had a
p
H optimum of 7.65 in imidazole buffer. The apparent
K
m
values were 4.6 × 10
−4
and 5.0 × 10
−4
m
for β-aspartyl semialdehyde and pyruvate, respectively. All attempts to demonstrate cofactor requirements were unsuccessful. Sulfhydryl inhibiting reagents and lysine did not inhibit the enzymatic reaction. The enzyme exhibited maximal thermal resistance at
p
H 10.5. The thermal stability of the enzyme at 75 C was increased more than 1,800-fold by the addition of 0.3
m
pyruvate. The
E
a
was 67,300 cal/mole for the thermal denaturation of the enzyme. At 60 C, the Δ
F
, Δ
H
, and Δ
S
values for the thermal denaturation of the enzyme were 22,250, 66,700, and 133 cal per mole per degree, respectively.
Structure of
Escherichia coli
After Freeze-Etching
Authors: Bayer M. E. , Remsen C. C.
Published: January 2020

Survival of
Escherichia coli
, quick-frozen under conditions similar to those employed for freeze-etching, is close to 100%. For determination of cell shrinkage, the diameters of freeze-etched
E. coli
cells (average, 0.99 μm) were compared with those of preparations after negative staining and after ultrathin sectioning. Negatively stained cells measured from 0.65 to 1.0 μm in diameter, and ultrathin sections showed average cell diameters of 0.70 μm. Freeze-etched replicas of logarithmically growing, as well as stationary,
E. coli
B cells revealed a smooth, finely pitted cell surface in contrast to cell surfaces seen with other preparative methods. The frozen cell wall may cleave in two planes, exposing (i) a smooth fracture face within the lipid layer and (ii) in rare instances an ill-defined particulate layer. Most frequently, however, cleavage of the envelope occurred between wall and protoplasmic membrane; large areas of the membrane were then exposed and showed a surface studded with predominantly spherical particles, an appearance which did not significantly change when the cells were fixed in formaldehyde and osmium tetroxide before freeze-etching. The distribution of these particles differed between logarithmically growing cells and stationary cells.
Merodiploid Ribosomal Loci Arising by Transformation and Mutation in Pneumococcus
Authors: Ravin Arnold W. , Takahashi Elaine A.
Published: January 2020

Merodiploid states have been detected in the
ery
and
str
loci of the pneumococcal genome. They are associated with particular mutations (
ery-r10
and
str-d2
) which add to, rather than replace their homologous sites during deoxyribonucleic acid (DNA)-mediated transformation. Markers at linked sites do not become diploid at the same time. The heterozygous condition thus produced is maintained during cell reproduction. However, in the case of the
ery
merodiploid at least, segregation of haploid types does occasionally occur. The transforming properties of DNA isolated from the merodiploids, taken together with the segregation patterns of the merodiploids, reveal the heterozygous condition. The merodiploid condition can be transferred via a single molecule of DNA, which can be explained by assuming that both alleles at the diploid site are integrated into the linear continuity of the bacterial chromosome. In the case of the
ery
merodiploid, two distinct, relatively stable but interconvertible states are recognizable. Their interconvertibility, as well as the segregation of hapliod descendants, can be explained as the result of occasional pairing of the duplicated regions with loss of one of these duplicated regions by recombination.
Differentiation of Two Groups of
Corynebacterium acnes
Authors: Voss J. G.
Published: January 2020

One hundred and forty-three strains of
Corynebacterium acnes
, isolated from human skin and acne lesions, were compared with three strains of
Propionibacterium acnes
from the American Type Culture Collection. The 146 organisms could be separated into two groups. Members of the larger group (129 strains) hydrolyzed gelatin and usually produced indole, Gel-In(+), but were unable to ferment trehalose, maltose, or sucrose, TMS(−). The deoxyribonucleic acid from selected strains of this group had an average guanosine + cytosine (GC) content of 60.5%. The members of the smaller group (17) were Gel-In(−), TMS(+), and the deoxyribonucleic acid had an average GC content of 63.9%. Studies with absorbed and unabsorbed antisera to the smaller group showed that although there were antigens shared by the two groups, it was possible to distinguish them serologically. Members of each group produced propionic acid. The principal fatty acid component of members of each group was iso-C
15
fatty acid. Seventy per cent of the Gel-In(+) strains were lysed by phage 174, whereas only one of 15 Gel-In(−) strains was lysed. Pending further information on the genetics of the two groups, those Gel-In(−), TMS(+) strains are tentatively designated
C. acnes
, group II.
On the Ornithinyl Ester of Phosphatidylglycerol of
Mycobacterium
607
Authors: Khuller G. K. , Subrahmanyam D.
Published: January 2020

Ornithinyl ester of phosphatidyl glycerol was found to accumulate in
Mycobacterium
607 under acidic conditions (
p
H 5.6) of growth or in cultures of ultraviolet-irradiated (320 to 420 nm) bacilli. There was a corresponding decrease in cardiolipin content of the organisms under these conditions.
Some Properties of the Pili of
Corynebacterium renale
Authors: Yanagawa Ryo , Otsuki Koichi
Published: January 2020

Some properties of the pili of the gram-positive bacteria
Corynebacterium renale
were described. A relationship was found between the morphological features of pili and the types of
C. renale
. Strains of types I and III usually possessed a small number of pili, whereas those of type II possessed numerous pili. Thick and long bundles of pili characteristic of
C. renale
were frequently observable in type II strains. Piliation of
C. renale
was stable under various cultural conditions. No ability to agglutinate red blood cells was demonstrated by piliated strains of
C. renale
. Pili were isolated from the cells of
C. renale
and studied serologically by immunodiffusion. The pili of a type II strain were serologically identical with the pili of another type II strain but not with those of the strains belonging to types I and III. The pili were serologically distinct from the cell wall. The pili were broken into short pieces by boiling, but their antigenicity was increased after boiling.
Reexamination of the Association Between Melting Point, Buoyant Density, and Chemical Base Composition of Deoxyribonucleic Acid
Authors: De Ley J.
Published: January 2020

The equations currently used for the calculation of the chemical base composition of deoxyribonucleic acid (DNA), expressed as moles per cent guanine plus cytosine (% GC), from either buoyant density (ρ) or midpoint of thermal denaturation (T
m
) were recalculated by using only sets of data on DNA determined with the same strains. All available information from the literature was screened and supplemented by unpublished data. The results were calculated by regression and correlation analysis and treated statistically. From the data on 96 strains of bacteria, it was calculated that% GC = 2.44 (T
m
– 69.4). T
m
appears to be unaffected by the substitution of cytosine by hydroxymethylcytosine. This equation is also valid for nonbacterial DNA. From the data on 84 strains of bacteria, the relation% GC = 1038.47 (–1.6616) was calculated. The constants in this equation are slightly modified when data on nonbacterial DNA are included. Both correlations differ only slightly from those currently used, but now they lean on a statistically sound basis. As a control, the relation between ρ and T
m
was calculated from data of 197 strains; it agrees excellently with the above two equations.
Depression of Guanosine Diphosphate-Mannose Pyrophosphorylase by Mutations in Two Different Regulator Genes Involved in Capsular Polysaccharide Synthesis in
Escherichia coli
K-12
Authors: Lieberman Michael M. , Markovitz Alvin
Published: January 2020

Mutations in a regulator gene (
capR
) that causes increased synthesis of capsular polysaccharide and derepressed synthesis of several enzymes involved in polysaccharide synthesis also derepress synthesis of guanosine diphosphate (GDP)-mannose pyrophosphorylase. In addition, a second mucoid mutation (
capS
, which maps separately from
capR
) also results in the derepression of GDP-mannose pyrophosphorylase. New conditions for assaying GDP-mannose hydrolyase and GDP-
l
-fucose synthetase permitted us to show that these enzymes are also derepressed in the
capS
mucoid strain. Although phosphomannose isomerase and uridine diphosphate-galactose-4-epimerase are derepressed in
capR
mucoid strains, they are not derepressed in
capS
mucoid strains. A nonmucoid mutant of a strain containing the
capR9
(mucoid) allele was deficient in GDP-mannose pyrophosphorylase.
Malate Utilization by a Group D
Streptococcus:
Regulation of Malic Enzyme Synthesis by an Inducible Malate Permease
Authors: London Jack , Meyer Eleanor Y.
Published: January 2020

Induction of an nicotinamide adenine dinucleotide-specific malic enzyme and a malate entry system permits
Streptococcus faecalis
to grow at the expense of malate. Evidence is presented which shows that biosynthesis of the permease, but not of the malic enzyme, is subject to catabolite repression by glucose. In contrast to the malic enzyme, the catalytic function of the entry system does not appear to be inhibited by intermediate products of glycolysis. Although the induction of the entry system does not appear to be coordinated with the induction of the malic enzyme, the latter process is dependent upon the permease for the transport and accumulation of inducer.
Divalent Cation Activation of Deoxycholate-Solubilized and -Inactivated Membrane Reduced Nicotinamide Adenine Dinucleotide Oxidase of
Bacillus megaterium
KM
Authors: Eisenberg R. C. , Yu L. , Wolin M. J.
Published: January 2020

After treating
Bacillus megaterium
KM membranes with 0.2% sodium deoxycholate, most of the membrane reduced nicotinamide adenine dinucleotide (NADH) oxidase was inactivated, and all of the membrane NADH-2,6 dichlorophenol indophenol oxidoreductase was solubilized. Dilution of the deoxycholate-treated membranes in the presence of divalent cations restored almost all of the original membrane NADH oxidase. The effectiveness of the divalent cation activation decreased in the order Ba
2+
> Ca
2+
> Mg
2+
> Mn
2+
. After centrifugation, the deoxycholate-treated membranes at 100,000 ×
g
for 1 hr, all of the NADH oxidase that was activated by a divalent cation was soluble. Cation-activated oxidase, however, was insoluble. The results show that 0.2% deoxycholate at least partially solubilizes the total electron chain from NADH to O
2
in an inactive from which can be reactivated by divalent cations with the formation of active, insoluble NADH oxidase.
Characterization of Altered Forms of Glycyl Transfer Ribonucleic Acid Synthetase and the Effects of Such Alterations on Aminoacyl Transfer Ribonucleic Acid Synthesis In Vivo
Authors: Folk William R. , Berg Paul
Published: January 2020

The glycyl transfer ribonucleic acid (tRNA) synthetase (GRS) activities of several
Escherichia coli glyS
mutants have been partially characterized; the
K
m
for glycine and the apparent
V
max
of several of the altered GRS differ significantly from the parental GRS. Paradoxically, some of the altered forms exhibit more activity in vitro than the GRS from a prototrophic strain (GRS

L

); several parameters of these activities have been studied in an attempt to resolve this problem. The amount of acylated tRNA
Gly
in vivo was examined to assess the GRS activities inside the cells. During exponential growth in media containing glycine, moderate amounts of acylated tRNA
Gly
occur in the
glyS
mutants; glycine deprivation leads to a dramatic drop in the amount of acylated tRNA
Gly
. An alternative measure of the in vivo activities of the altered enzymes is the efficiency of suppression of the
trpA36
locus by
su
36
+
;
glyS
mutants grown with added glycine exhibit one-third to one-fourth the suppression efficiency of the prototrophic
glyS
H
parent, presumably because they are less efficient, even in the presence of high levels of glycine, in charging the tRNA
Gly
species which functions as the translational suppressor.
Subterminal Oxidation of Aliphatic Hydrocarbons
Authors: Forney F. W. , Markovetz A. J.
Published: January 2020

Evidence is presented for a catabolic pathway of
n
-alkane oxidation which proceeds via subterminal oxidation rather than methyl group oxidation.
Osmotic Properties of Spheroplasts fromSaccharomyces cerevisiaeGrown at Different Temperatures
Authors: Diamond R. J. , Rose A. H.
Published: January 2020

Spheroplasts were prepared from cells ofSaccharomyces cerevisiaeNCYC 366, grown at 30 or 15 C, by incubating cells with snail-gut juice after pretreatment with 2-mercaptoethanol. Walls of cells grown batchwise or in continuous culture at 15 C were more resistant to digestion with snail juice than walls on cells grown under the same conditions as 30 C. Spheroplasts lysed when suspended in hypotonic solutions of mannitol. The resistance of spheroplasts to osmotic lysis tended to increase when the test temperature was lowered below 30 C. The increased resistance was greater with spheroplasts from cells grown at 15 C. Cations, especially Ca2+, protected spheroplasts against osmotic lysis. In general, the protective effects, measured at 30 C, were smaller with spheroplasts from cells grown at 15 C compared with 30 C. Citrate and ethylenediaminetetraacetate (EDTA) decreased the resistance of spheroplasts to osmotic lysis. On the whole, the decrease was greater with spheroplasts from cells grown at 30 C rather than 15 C. In the presence of EDTA, spheroplasts from cells grown at 30 C were less resistant to osmotic lysis at 5 C than at 30 C; when spheroplasts from cells grown at 15 C were similarly examined, they were more resistant to lysis at 5 C than at 30 C. Spheroplast membranes from cells grown at 15 C had slightly but significantly greater contents of Mg2+, Ca2+, K+, and Na+compared with spheroplast membranes from cells grown at 15 C. Mg2+and Ca2+were more easily extracted with EDTA from membranes of 30 C-grown cells than from 15 C-grown cells.
Release of Membrane Components from Viable
Haemophilus parainfluenzae
by Ethylenediaminetetraacetic Acid-Tris(hydroxymethyl)-aminomethane
Authors: Tucker Anne N. , White David C.
Published: January 2020

Logarithmically growing
Haemophilus parainfluenzae
lost 15 to 20% of the phospholipids, demethyl vitamin K
2
, cytochrome
b
, and cytochrome
c
, and 50% of the lipopolysaccharide when incubated in ethylenediaminetetraacetic acid (EDTA)-tris-(hydroxymethyl)aminomethane (Tris) for 10 min. This loss of membrane components occurred without loss in viability, and the lost components were recovered as membrane fragments in the surrounding buffer. The phospholipids recovered in the membrane fragments had a slightly lower specific activity than the phospholipids in the residue. Lysis of a portion of the cells could not account for the release of membrane components, as the cells lost neither glucose-6-phosphate dehydrogenase activity not deoxyribonucleic acid. The treated cells were osmotically stable and contained the same proportions of the individual phospholipids as pretreatment cells. Prolongation of the EDTA-Tris treatment did not induce further loss of phospholipid or demethyl vitamin K
2
, but caused a decrease in viability. If the cells were returned to the growth medium after 10 min, the cells immediately resumed growth at the pretreatment rate. During growth in the recovery period, the phospholipids increased logarithmically in the pretreatment rate. During growth in the recovery period, the phospholipids increased logarithmically in the pretreatment proportions, although there was a marked decrease in the turnover and a shift from the use of extracellular lipid precursors to the use of intracellular pools of precursors.
Bacteriophage Receptor Development and Synthesis of O-Specific Side Chains After Addition of
d
-Galactose to the Uridine Diphosphate-Galactose-4-Epimeraseless Mutant
Salmonella typhimurium
LT2-M1
Authors: Lindberg A. A. , Holme T. , Hellerqvist C. G. , Svensson S.
Published: January 2020

The formation of complete cell wall core lipopolysaccharide (LPS) and O-antigenic side chains after addition of
d
-galactose to the uridine diphosphate-galactose-4-epimeraseless mutant,
Salmonella typhimurium
LT2-M1, has been studied by (i) determination of adsorption rates of smooth and rough specific bacteriophages, (ii) passive hemagglutination inhibition, and (iii) qualitative and quantitative determination of the polysaccharide composition and structure. A rapid synthesis of the complete core LPS and O side chains occurred in bacteria in the log phase and the early stationary phase. Phage C21, which attaches to unsubstituted Rc structures, was adsorbed by the bacteria for only 10 min after the addition of
d
-galactose. Unsubstituted Rc structures, however, could still be detected after 160 min by immunological and chemical assays. Attachment of the P22 phage, which requires O-specific side chains with more than one repeating unit for adsorption, was demonstrated 10 min after the addition of
d
-galactose. Attachment of the Felix O-1 phage, which requires a complete core, was observed between 20 and 80 min after the addition of
d
-galactose. The rough specific phages 6SR and Br2 did not adsorb to the bacteria at any time after the addition of
d
-galactose. By passive hemagglutination inhibition, the presence of O-specific structures could be demonstrated after 10 min. No antigenic activity of the Ra and Rb structures was observed in the LPS preparations isolated at any time after the addition of
d
-galactose. Methylation analysis of LPS preparations isolated at 10 and 160 min after the addition of
d
-galactose showed that the O-specific side chains contained an average of 11 and 15 repeating units, respectively. In the 10-min sample, every 25th “Rc structure” carried a side chain, compared to every 3rd residue in the 160-min sample.
Association of the Crystalline Inclusion of
Bacillus thuringiensis
with the Exosporium
Authors: Somerville Hugh J. , James Cheryl R.
Published: January 2020

Thin sections of sporulating cells of
Bacillus thuringiensis
show a marked association between the crystalline inclusion and the exosporium.
Metabolism of
14
C-Urea by T-Strain Mycoplasma
Authors: Ford Denys K. , McCandlish K. Lianne , Gronlund Audrey F.
Published: January 2020

When
14
C-labeled urea was metabolized by T-strain mycoplasma, 94 to 95% of the radioactivity was recovered as
14
CO
2
, and significant radioactivity was not incorporated into cellular material.
Regulation of Aromatic Amino Acid Biosynthesis in Phenazine-Producing Strains of
Pseudomonas
Authors: Levitch Mark E.
Published: January 2020

Regulation of 3-deoxy-
d
-
arabino
-heptulosonate-7-phosphate (DAHP) synthetase was studied in eight strains of
Pseudomonas
which synthesize phenazine compounds. Repression studies with individual aromatic amino acids led to the finding that enzyme synthesis was repressed in only one strain,
P. aureofaciens
B1543p, and by only one amino acid,
l
-tyrosine. Feedback inhibition by the aromatic amino acids varied from strain to strain in terms of the type of inhibitory control, and the particular acid or acids which inhibited. Prephenate and chorismate, as well as a number of naturally occurring phenazine compounds, inhibited the DAHP synthetase activity to varying degrees.
Carotenoid Formation by
Staphylococcus aureus
Authors: Hammond Ray K. , White David C.
Published: January 2020

The carotenoid pigments of
Staphylococcus aureus
U-71 were identified as phytoene; ζ-carotene; δ-carotene; phytofluenol; a phytofluenol-like carotenoid, rubixanthin; and three rubixanthin-like carotenoids after extraction, saponification, chromatographic separation, and determination of their absorption spectra. There was no evidence of carotenoid esters or glycoside ethers in the extract before saponification. During the aerobic growth cycle the total carotenoids increased from 45 to 1,000 nmoles per g (dry weight), with the greatest increases in the polar, hydroxylated carotenoids. During the anaerobic growth cycle, the total carotenoids increased from 20 nmoles per g (dry weight) to 80 nmoles per g (dry weight), and only traces of the polar carotenoids were formed. Light had no effect on carotenoid synthesis. About 0.14% of the mevalonate-
2
-
14
C
added to the culture was incorporated into the carotenoids during each bacterial doubling. The total carotenoids did not lose radioactivity when grown in the absence of
14
C for 2.5 bacterial doublings. The total carotenoids did not lose radioactivity when grown in the absence of
14
C for 2.5 bacterial doublings. The incorporation and turnover of
14
C indicated the carotenes were sequentially desaturated and hydroxylated to form the polar carotenoids.
Genetic Mapping and Dominance of the Amber Suppressor,
Su1
(
supD
), in
Escherichia coli
K-12
Authors: Hoffman Edwin P. , Wilhelm Robert C.
Published: January 2020

In this report
Su1
(
supD
), which is known to suppress “amber” mutations by means of a specific transfer ribonucleic acid, has been mapped relative to
his
and
uvrC
and has been found to be located at about 37.5 min on the Taylor and Trotter genetic map of the
Escherichia coli
K-12 chromosome. In addition,
Su1
+
has been shown to be dominant over
Su1
−
, which supports the idea that
Su1
is the structural gene for the suppressing transfer ribonucleic acid.
Comparisons of F Factors and R Factors: Existence of Independent Regulation Groups in F Factors
Authors: Morrison Trudy G. , Malamy Michael H.
Published: January 2020

The similarity of sex pili mediated by F factors and R(fi
+
) factors and the ability of R(fi
+
) factors to control by repression the functioning of pilus genes encoded by the F factor suggested that F factors and R(fi
+
) factors are closely related. Further comparisons of the episomal properties of F factors and R(fi
+
) factors, however, indicated many differences. F factors contain information for a restriction system for phages φII and T7. Cells containing R factors are sensitive to these phages. Furthermore, R(fi
+
) factors do not repress the F factor φII restriction system in cells containing both an R(fi
+
) factor and an F factor. R factors and F factors are heteroimmune episomes. In addition, an R(fi
+
) factor in cells containing both an R factor and an F factor does not fully repress the expression of F-factor immunity to an incoming second F factor. R-factor and F-factor replication systems are not identical. Wild-type F-factor replication genes will complement the mutant F
ts114
lac
+
replication genes in cells containing two F factors. The F
ts114
lac
+
episome is retained when these cells are grown at 42 C; however, cells containing an R(fi
+
) factor and F
ts114
lac
+
lose the F
ts114
lac
+
when grown at 42 C, at the same rate as cells containing only the F
ts114
lac
+
. The replication system of the R(fi
+
) factor will not complement the mutant F
ts114
lac
+
replication system.
Differential Protein Synthesis During Sporulation in the Slime Mold
Physarum polycephalum
Authors: Jockusch Brigitte M. , Sauer Helmut W. , Brown Donna F. , Babcock Karlee L. , Rusch Harold P.
Published: January 2020

The size distribution and synthesis of polypeptide chains and the polysome patterns were studied during sporulation of the slime mold
Physarum polycephalum
, and were compared with nonsporulating controls. The proteins were divided into a 27,000 ×
g
supernatant (buffer-soluble proteins) and a pellet (buffer-insoluble proteins) while still native. The sodium dodecyl sulfate complexes of the denatured proteins were separated on polyacrylamide gels containing urea. The following differences were found between sporulating and nonsporulating cultures. (i) The distribution of the soluble proteins into bands from sporulating and control cultures was the same in stained patterns; however, there was a slight shift toward increased synthesis of larger polypeptide chains in the radioactivity patterns of the soluble proteins in sporulating cultures. (ii) The amount of histones in the sporulating cultures was less than 30% of the values in the controls. Also, histone synthesis was reduced to less than 10% of that in the nonsporulating controls. In addition, proteins in three defined regions, corresponding to molecular weights of 70,000 to 75,000 (I), 55,000 (II), and 41,000 (III), were synthesized in sporulating cultures at a rate at least twice that in controls. Polypeptides corresponding to peaks I and II could be extracted from purified walls of mature spores. (iii) The polysome pattern as revealed by sucrose density centrifugation showed a breakdown of heavy polysomes at 3 hr after illumination, with their reappearance 4 hr later. The latter pattern, however, differed from that of the nonsporulating control in that the amount of light polysomes was reduced. This might account for the reduction in histone synthesis.
Cell Wall Binding Properties of the
Bacillus subtilis
Autolysin(s)
Authors: Fan David P.
Published: January 2020

Cell walls isolated from exponentially growing
Bacillus subtilis
have autolysin(s) attached to them. An autolysin can be released from the walls by incubation at 0 C with 3
m
LiCl. The enzyme can reattach to walls when the salt concentration is reduced. The bound enzyme cannot be removed or destroyed by washing the walls with 8
m
urea at 0 C. The binding of free enzyme to walls at 0 C can take place normally in the presence of 2
m
urea.
Regulation of Thymidine Metabolism in
Escherichia coli
K-12: Optimal Conditions for the Assay of 1,5-Phosphodeoxyribomutase in Ultrasonic Extracts
Authors: Bonney Robert J. , Weinfeld Herbert
Published: January 2020

Assay conditions have been established which allow maximum expression of phosphodeoxyribomutase activity in ultrasonic extracts of
Escherichia coli
K-12. The enzyme requires 2-mercaptoethanol, manganous ions, and glucose 1,6-diphosphate for optimal activity. When cells are grown in minimal medium with glycerol as the carbon source and supplemented with 10
−3
m
thymidine, phosphodeoxyribomutase is induced three- to four-fold. Cell pellets may be frozen for 24 hr before sonic disruption without loss of enzyme activity. The assay is highly reproducible.
Cyclic 3′,5′-Adenosine Monophosphate and
N
-Acetyl-glucosamine-6-Phosphate as Regulatory Signals in Catabolite Repression of the
lac
Operon in
Escherichia coli
Authors: Goldenbaum Paul E. , Broman Rodney L. , Dobrogosz Walter J.
Published: January 2020

When an
Escherichia coli
mutant lacking the enzyme
N
-acetyl-glucosamine-6-phosphate (AcGN6P) deacetylase is grown in a succinate-mineral salts medium and exposed to an exogenous source of
N
-acetylglucosamine, approximately 20 to 30 pmoles of AcGN6P per μg of cell dry weight will accumulate in these cells. This accumulation occurs within 2 to 4 min after the addition of
N
-acetylglucosamine and is coincident with the production of a severe permanent catabolite repression of β-galactosidase synthesis. This repression does not occur if adenosine 3′,5′-cyclic phosphate (cyclic AMP) is added to the cells before AcGN6P accumulates. An immediate derepression occurs when cyclic AMP is added to cells that have already accumulated a large AcGN6P pool. These findings are consistent with the view that low-molecular-weight carbohydrate metabolites and cyclic AMP play key roles in the catabolite repression phenomenon, and that metabolites such as AcGN6P may participate in the represion mechanism by influencing either the formation or degradation of cyclic AMP in
E. coli
.
Clostridium oceanicum
, sp. n., a Sporeforming Anaerobe Isolated from Marine Sediments
Authors: Smith Louis Ds.
Published: January 2020

Fourteen strains of a terminal-spored anaerobe were isolated from marine sediments obtained off the Atlantic and Pacific coasts of tropical South America. These strains are proteolytic, lecithinolytic, only slightly saccharolytic, often form cells with two spores, and appear unlike any described species of terminal-spored, proteolytic anaerobe. The name
Clostridium oceanicum
is suggested. The type strain (no. 25647) is deposited in the American Type Culture Collection.
Occurrence of
Crithidia
Factors and Folic Acid in Various Bacteria
Authors: Iwai K. , Kobashi M. , Fujisawa H.
Published: January 2020

Crithidia
factors and folic acid were found to be widely distributed in culture fluids and in cells of 27 species of bacteria, when cultured under aerobic conditions into the stationary phase. Most bacteria excreted more
Crithidia
factors and folic acid than they retained in their cells. One
Crithidia
factor produced by
Serratia indica
and one produced by
Bacillus cereus
differed from biopterin in their chromatographic behavior. The factor excreted by
S. indica
appeared to be a 2-amino-4-hydroxy-6-substituted pteridine on the basis of KMnO
4
oxidation and ultraviolet absorption spectra. One of the folate compounds excreted by this organism was shown to be identical to 5,10-methylidynetetrahydrofolic acid by bioautography.
Conditional Mutants of Meiosis in Yeast
Authors: Esposito Michael S. , Esposito Rochelle E. , Arnaud Maryvonne , Halvorson H. O.
Published: January 2020

Three temperature-sensitive mutants, spo1-1, spo2-1, and spo3-1, were characterized with respect to their behavior in sporulation medium at a restrictive temperature. The time of expression of the functions defective in the mutants was determined by temperature-shift experiments during the sporulation process. In addition, each mutant was examined for the following: (i) its ability to undergo the nuclear divisions of meiosis; (ii) deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein synthesis; (iii) protein turnover; and (iv) colony-forming ability after exposure to sporulation medium. Mutant spo1-1 is defective in a function which confers a temperature-sensitive period which extends over 32% of the sporulation cycle. The temperature-sensitive period of mutant spo2-1 occupies 34% of the cycle, whereas the temperature-sensitive period of mutant spo3-1 extends over 2% of the sporulation cycle. Cytological evidence indicates that all three mutants initiate but do not complete the meiotic nuclear divisions. The DNA content of sporulation cultures of mutants spo1-1 and spo3-1 did not increase to the wild-type level; DNA synthesis in spo2-1 was normal. All three strains exhibit a loss of colony-forming ability during incubation in sporulation medium at the restrictive temperature. RNA and protein synthesis and protein turnover occur in the mutants.
Characterization of Canine Mycoplasmas by Polyacrylamide Gel Electrophoresis and Immunodiffusion
Authors: Armstrong D. , Yu B.
Published: January 2020

Canine mycoplasmas which had been characterized by biological and serological methods were further studied by using polyacrylamide gel electrophoresis (PGE) and double diffusion in agar gel. The three dog mycoplasmas previously characterized,
Mycoplasma canis, M. maculosum
, and
M. spumans
showed distinctive patterns by PGE. Five additional representative isolates from dogs had been characterized serologically and biologically into three new groups, A, C, and D. An additional mycoplasma (group B) was indistinguishable from
M. canis
by growth inhibition and PGE but was more broadly reactive with field isolates serologically. The group A organisms were distinctive in pattern and similar to those studied by Razin and Rottem, tentatively designated
M. edwardii
. The group C organisms were represented by two isolates which were similar by fluorescent-antibody studies but different by growth inhibition tests. These two isolates were also different from each other by PGE. The group D serotypes were also distinctive by PGE from all other dog mycoplasmas tested. It was found, during these studies, that two different mycoplasmas showed different PGE patterns at different intervals during incubation. Immunodiffusion studies showed a relationship among all the canine mycoplasmas, and bands of nonidentity between the two group C mycoplasmas were demonstrated.
Changes in Membrane Lipid Composition in Exponentially Growing
Staphylococcus aureus
During the Shift from 37 to 25 C
Authors: Joyce G. H. , Hammond R. K. , White David C.
Published: January 2020

Lowering the temperature of growth of
Staphylococcus aureus
from 37 to 25 C decreased the growth rate and induced changes in the composition of the membrane lipids. Changes in lipid composition also occur in the transition between exponential and stationary growth phases at one temperature. To isolate the effects of lowering the temperature, exponentially growing
S. aureus
was abruptly switched from 37 to 25 C by transfer to cooler medium. Exponential growth continued at 25 C without a lag period but with a threefold increase in doubling time. In the period of exponential growth at suboptimal temperature, there was essentially no change in the fatty acid composition of the lipids, little change in the vitamin K
2
composition with perhaps a slight increase in the total level, and essentially no change in the phospholipid composition, but a marked stimulation of the synthesis of the rubixanthins. Growth of cells at 25 C was much more sensitive to the inhibition of rubixanthin formation by mixed-function oxidase inhibitors than cells growing at 37 C, suggesting some function for the rubixanthins at suboptimal temperatures. The striking increases in the proportions of monoenoic fatty acids observed at lowered growth temperatures in many biological systems are not detected in
S. aureus
.
Fine Structure of
Thermus aquaticus
, an Extreme Thermophile
Authors: Brock Thomas D. , Edwards Mercedes R.
Published: January 2020

Electron microscopic studies using thin sections revealed that
Thermus aquaticus
has a structure similar to that of most other gram-negative bacteria. The cell envelope is tripartite: plasma membrane, thin middle layer, and a thicker and irregular outer layer. The outer layer appears to be joined to the plasma membrane by a series of connections and, when seen in tangential section, the outer layer appears as a series of parallel bands. The cell division mechanism resembles that of typical gram-negative bacteria. Large spherical bodies designated “rotund bodies” are formed as a result of the association of a number of separate cells. In this association the outer envelope layers of the cells fuse and pull away from the middle layer. The rotund body thus appears as a series of rods, usually lying in parallel around the periphery of the sphere, completely connected by means of the fused outer layer.