bluuebunny/crossref_metadata_2025 huggingface dataset:
Posttranscriptional Control of Tyrosine Aminotransferase Synthesis by Insulin
Authors: Gelehrter Thomas D. , Tomkins Gordon M.
Published: May 2006

Adrenal steroid hormones induce the synthesis of tyrosine amino-transferase (TAT) in HTC cells, an established line of rat hepatoma cells in tissue culture. The addition of insulin to cells previously induced in a serum-free medium results in a rapid two- to threefold further increase in the rate of synthesis of TAT and a small increase in total amino acid incorporation. These changes do not require concomitant RNA synthesis, suggesting that insulin acts at a step in protein synthesis beyond that of gene transcription. Although the effects of insulin on HTC cells are similar to those caused by dialyzed bovine serum, evidence is presented that insulin and serum affect different aspects of TAT synthesis. Unlike the glucocorticoids, insulin does not cause the accumulation of TAT mRNA, nor the sustained induction of TAT. The continued presence of the inducing steroid is required to permit maximal expression of the insulin effect.
Electrophoretically Homogeneous Anti-DNP Antibodies with Restricted Isoelectric Points Elicited in Mice by Immunization with the Antigen Papain-S-DNPL
Authors: Trump Gary N. , Singer S. J.
Published: May 2006

The primary immunization of outbred mice with the antigen Pap-S-DNPL results in the generation of low titers of anti-DNP antibody which in about one-third of the responding animals is as homogeneous as a myeloma protein by the combined criteria of (
a
) isoelectric focusing in gels and (
b
) gel electrophoresis of the antibody light chains. The electrophoretically homogeneous antibodies show a marked restriction of isoelectric points near pH 5.0. Such marked selectivity of the antihapten antibodies appears to result from the chemical and structural homogeneity of the Pap-S-DNPL antigen.
Glucose-6-Phosphate Dehydrogenase and
Neurospora
Morphology
Authors: Scott W. A. , Tatum E. L.
Published: May 2006

In addition to the
Neurospora crassa
mutant
col
-2, mutations in two other unlinked genes, balloon and frost, lead to distinct morphological growth and abnormal glucose-6-phosphate dehydrogenases. The glucose-6-phosphate dehydrogenases from these strains have increased thermolabilities, altered kinetic parameters, and distinctive electrofocusing patterns. The altered enzyme segregates with each morphological phenotype in crosses to wild type, and there is a correlation between the severity of the enzymic defect and the degree of morphological abnormality in heterocaryons and double mutants.

These results are compatible with the hypotheses that the balloon, frost, and
col-2
genes are structural genes for glucose-6-phosphate dehydrogenase and that the pleiotropic effects of these altered dehydrogenases are responsible for the mutant morphologies.
Bacteriophage Lambda; Abortive Infection of Bacteria Lysogenic for Phage P2
Authors: Lindahl Gunnar , Sironi Gianpiero , Bialy Harvey , Calendar Richard
Published: May 2006

The efficiency of plating of wild-type λ on a host lysogenic for P2 is less than 10
-6
, and only a small number of infected cells produce progeny phage. Lambda can adsorb and inject its DNA normally in such cells; the DNA can circularize and is not nicked or degraded, but replication is severely impaired. Mutants of P2, which as prophages no longer interfere with λ, have been isolated and found to be recessive to wild type, implying that P2 prophage codes for a diffusible product involved in λ interference. The P2 gene product responsible for preventing λ growth also kills recombination-deficient bacteria of the
recB
and
recC
classes under conditions where P2 does not normally kill the host. Mutants of λ that are resistant to interference are recessive to wild-type λ. Thus λ actively participates in its own interference. The λ-mutants that are resistant to interference are unable to synthesize at least two nonessential proteins. In addition, they are unable to grow on recombination-deficient bacteria of the
recA
class, but they can grow on
recA recB
double mutants.
Dinucleotides as Products of an Exonucleolytic Activity Associated with the
Micrococcus luteus
DNA Polymerase
Authors: Harwood S. J. , Schendel P. F. , Miller L. K. , Wells R. D.
Published: May 2006

The partially purified DNA polymerase from
Micrococcus luteus
contains a low level of exonucleolytic activity. The enzyme preparation (1200-fold purified) contains approximately 100 times more polymerase than exonuclease activity. Both single- and double-stranded DNA are degraded at the same rate. The predominant products are dinucleoside diphosphates (d-pXpY); mononucleotides and a trace of trinucleotides are also produced. Each of these products is formed at a constant rate throughout the course of the reaction. The nuclease degrades a DNA chain from the 5′-end. The enzyme preparation contains no detectable endonuclease activity.
Subunit Structure of Human Fibrinogen, Soluble Fibrin, and Cross-Linked Insoluble Fibrin
Authors: McKee Patrick A. , Mattock Patrick , Hill Robert L.
Published: May 2006

The three unique polypeptide chains of human fibrinogen differ significantly in molecular weight. Cross-linkage of fibrin by fibrin-stabilizing factor results in the rapid formation of cross-links between γ-chains and a slower formation of cross-links between α-chains. β-Chains are not involved directly in the cross-linking of fibrin. Reduced, cross-linked fibrin contains uncross-linked β-chains, dimers of γ-chain, and higher polymers of α-chain. Although it is uncertain whether the γ-γ dimers are formed by chains in different molecules of fibrin, the polymers of α-chain in fibrin can only be accounted for by cross-linkage of α-chains in different molecules. The nature of cross-linkage among the subunits in fibrin can account well for the three-dimensional, covalent structure of cross-linked, insoluble fibrin.
Precipitation of Proteins by Vinblastine and Calcium Ions
Authors: Wilson L. , Bryan J. , Ruby A. , Mazia D.
Published: May 2006

We have found that vinblastine sulfate can precipitate a number of proteins in addition to microtubule protein. Those proteins which precipitate with vinblastine sulfate, all of which were derived from structure, also precipitate with Ca
2+
ions. Our results suggest that vinblastine sulfate, presumably acting as a cation, precipitates proteins by combining with sites which can also combine with Ca
2+
ions.
Conversion of Bacterial Aldolase from Vegetative to Spore Form by a Sporulation-Specific Protease
Authors: Sadoff H. L. , Celikkol Emel , Engelbrecht H. L.
Published: May 2006

A protease is elaborated by cells of
Bacillus cereus
during sporulation. This sporulation-specific enzyme, in a limited proteolysis, converts vegetative cell aldolase to spore aldolase.
Isolation and Characterization of Structurally Homogeneous Antibodies from Antipneumococcal Sera
Authors: Jaton Jean-Claude , Waterfield Michael D. , Margolies Michael N. , Haber Edgar
Published: May 2006

Antibodies of sufficient homogeneity for sequence studies were readily obtained in high concentrations from rabbits immunized with pneumococcal vaccines. By taking advantage of slightly differing immunologic specificity for Type III and Type VIII capsular polysaccharides, an antibody with unique electrophoretic mobility could be isolated from serum containing several distinct antibody components by using appropriate cross-reacting immunoadsorbents. A unique sequence for the N-terminal 11 amino acid residues of the light chain of the antibody was found, in contrast to several sequences in the antibody mixture from which this component was isolated. The sequence of a nonimmune light chain pool demonstrates even greater heterogeneity. Chymotryptic peptide maps of the antibody light chain show two unique cysteine-containing variable region peptides not seen in maps of nonimmune light chain pool of the same allotypic specificity as that of the antibody light chain. The experimental approach described here may provide further insight into the structure-function relationship of several homogeneous antibodies of closely related specificity for the same polysaccharide antigen.
Attachment of Carbohydrate to the Variable Region of Myeloma Immunoglobulin Light Chains
Authors: Sox Harold C. , Hood Leroy
Published: May 2006

Approximately 15 per cent of the light chains from homogeneous immunoglobulins in patients with multiple myeloma contain an oligosaccharide group. Five human myeloma light chains that contained carbohydrate were studied. The sequence Asn-[unk]-Ser/Thr was at the site of carbohydrate attachment in all light chains. The carbohydrate group was attached to the asparagine residue of this triplet sequence which in all five light chains was located in the variable region. The occasional occurrence of carbohydrate in myeloma light chains is seen as the consequence of a variable region mutation creating an Asn-[unk]-Ser/Thr sequence to which carbohydrate is attached by an enzyme capable of recognizing the characteristic triplet sequence.
OXIDIZED RNASE AS A PROTEIN MODEL HAVING NO CONTRIBUTION TO THE HYDROGEN EXCHANGE RATE FROM CONFORMATIONAL RESTRICTIONS
Authors: Woodward C. K. , Rosenberg Andreas
Published: May 2006

As oxidized RNase is a model for the random conformation state of RNase, the hydrogen exchange kinetics of oxidized RNase approximate the intrinsic conformation-independent chemical exchange rate of the native protein. The energy of activation, the pH
min
, and the
k
min
of oxidized RNase exchange rates are similar to those reported for amino acid homopolymers. However, unlike the exchange from homopolymers, the exchange from oxidized RNase is characterized by a distribution of first-order rates. This distribution is important to the analysis of exchange from native proteins in terms of classes of sites which share common structural properties.
ANALYSIS OF T4 PHAGE PROTEINS, I. CONVERSION OF PRECURSOR PROTEINS INTO LOWER MOLECULAR WEIGHT PEPTIDES DURING NORMAL CAPSID FORMATION
Authors: Hosoda Junko , Cone Ric
Published: May 2006

Radioisotopically labeled T4-proteins extracted from purified capsids and phage and from infected cells were separated by gel electrophoresis in the presence of sodium dodecyl sulfate and a reducing reagent. They were identified by autoradiography and by counting of the fractionated gels.

Four major protein bands (F, A, D, and E) were detected in capsid and phage. These accounted for more than 90% of the total capsid protein and 70% of the phage protein (60% of the total capsid protein was in A-band). Coelectrophoresis of [
14
C]proteins from capsids and [
3
H]proteins from phage-infected cells indicated that the protein coded by gene 23 (P23) was a peptide chain approximately 25% longer than A-protein. Pulse-chase experiments combined with differential extraction indicated that conversion of P23 into A-protein and alteration of the protein coded by gene 22 (P22) appeared to be vital steps in formation of normal capsids. Mutations in several other genes known to prevent normal capsid formation inhibited conversion of P23 to A-protein and alteration of P22.
PROTEIN CHAIN INITIATION IN RABBIT RETICULOCYTES
Authors: Wilson David B. , Dintzis Howard M.
Published: May 2006

About 15% of the nascent α-chains isolated from
in vivo
labeled rabbit reticulocytes have methionine as their amino terminal amino acid. The methionine is predominantly on the shortest nascent chains, suggesting that methionine initiates the synthesis of rabbit hemoglobin and is rapidly removed during further synthesis.
Biochemical and Genetic Studies of Recombination Proficiency in
Escherichia coli
, II. Rec
+
Revertants Caused by Indirect Suppression of Rec-Mutations
Authors: Barbour Stephen D. , Nagaishi Haruko , Templin Ann , Clark Alvin J.
Published: May 2006

All
recB
-
and
recC
-
mutants of
E. coli
carry out significant residual genetic recombination, whereas all
recA
-
mutants form no recombinants. This observation suggests that an alternative minor pathway of recombination, independent of
recB
+
and
recC
+
products, may be operative in
Escherichia coli
. Rec
+
revertants of
recB
-
recC
+
,
recB
+
recC
-
, and
recB
-
strains of
E. coli
have been isolated and are shown to fall into at least two major genotypic classes. One class carries revertant mutations which map in or very near the
recB
and
recC
genes. In this class an ATP-dependent DNase characteristic of wild type
E. coli
is restored. The reversions in this class are probably back-mutations or intragenic suppressor mutations. A second class carries revertant mutations which are located far from the
recB
and
recC
genes. In this class there is a high level of DNase activity which does
not
require ATP and is inactive on T4 DNA. Indirect and not informational suppression appears to be responsible for the second class of revertants. The suggestion is made that restoration of recombination by indirect suppression involves an activation or derepression of one or a series of enzymes, which participate in a pathway of recombination, alternative to the
recB
and
recC
pathway, but normally of minor importance. The ATP-independent DNase may be one of these enzymes.
DNA Polymerase Activity Associated with RNA Tumor Viruses
Authors: Hatanaka M. , Huebner R. J. , Gilden R. V.
Published: May 2006

C-type RNA viruses, originating in mouse, cat, hamster, and viper, catalyze the synthesis of DNA from its constituent deoxyribonucleoside triphosphates. Both the rate and extent of the reaction were significantly enhanced by brief treatment of the intact virus with ether. A proportion of the newly synthesized DNA was associated with virions when intact virus was used as template; this was not the case with ether-treated virus. In both cases, DNA extracted from the reaction mixture sedimented slowly, at about 2-4 S.
A Capillarity Mechanism for Diatom Gliding Locomotion
Authors: Gordon Richard , Drum Ryan W.
Published: May 2006

It is proposed that the diatom raphe is a parallel-plate capillary containing a fluid which reacts at the trailing end, turning into a form which no longer „wets” the raphe walls, and which is left behind as a trail. More unreacted raphe fluid is drawn by capillary pressure from a source near the leading end of the raphe. This fluid sticks out from the raphe along its length, adhering to surfaces, thus causing gliding locomotion. Formulae are given for the maximum velocity and force of a moving diatom in terms of the raphe dimensions and the surface tension and viscosity of the fluid. An
a priori
estimate of the force exerted by a moving diatom, 1-50 millidynes, agrees with measured values. Five experimental tests of the theory are proposed.
Mechanism of Carcinogenesis by RNA Tumor Viruses, I. An RNA-Dependent DNA Polymerase in Murine Sarcoma Viruses
Authors: Green Maurice , Rokutanda Makoto , Fujinaga Kei , Ray Ranjit Kumar , Rokutanda Hinae , Gurgo Corrado
Published: May 2006

A highly active and stable DNA polymerase was found in purified preparations of two murine sarcoma viruses. Enzyme activity is not detected in most virus preparations unless they are treated with low concentrations of a nonionic detergent such as Nonidet P-40. The incorporation of labeled thymidine triphosphate requires all four deoxyribonucleoside triphosphates and either Mg
2+
or Mn
2+
. Enzyme activity is proportional to virus concentration and is linear with time up to 90 min. That the template is RNA is suggested by the reduction in polymerase activity upon treatment of murine sarcoma virus with RNase, and by the absence of detectable amounts of DNA in the virus. That the product is DNA is shown by the incorporation of all four deoxyribo-nucleoside triphosphates into an acid-insoluble product which is stable in alkali, is destroyed by DNase, sediments in alkaline sucrose gradients with a sedimentation coefficient of 7 S, and bands in isopycnic CsCl gradients with a mean buoyant density of 1.700.
Comparative Study of the Primary Structures of Cytochrome
b
5
from Four Species
Authors: Tsugita Akira , Kobayashi Midori , Tani Seiji , Kyo Sukei , Rashid M. A. , Yoshida Yukuo , Kajihara Toshimasa , Hagihara Bunji
Published: May 2006

The primary structures of human, bovine, and chicken cytochrome
b
5
have been determined and compared with that of the previously studied rabbit protein. One peptide containing 31 amino acid residues and another containing 10 were found common to all four species. The substitutions of amino acids between species could be accounted for mainly by single base exchange, with a few exceptional double base exchanges for the chicken. Results for bovine cytochrome
b
5
differ significantly from those previously reported for calf cytochrome
b
5
.
Replication of Repetitious DNA and the S Period
Authors: Comings David E. , Mattoccia Emilio
Published: May 2006

The renaturation kinetics of labeled DNA derived from synchronized Chinese hamster cells indicate that the three classes of repetitious DNA replicate uniformly throughout the S period, and that a piece of repetitious DNA may occur at or near the beginning of each replicon. Studies with mouse-cell DNA suggest that mouse satellite DNA replicates when euchromatin replicates.
Low Temperature and Chloramphenicol Induction of Respiratory Deficiency in a Cold-Sensitive Mutant of
Saccharomyces cerevisiae
Authors: Weislogel Paul O. , Butow Ronald A.
Published: May 2006

A cold-sensitive mutant of a haploid strain of
Saccharomyces cerevisiae
has been isolated by selection for impaired growth at 18° on nonfermentable carbon sources. Growth of the mutant on glucose or galactose at either 28 or 18° is similar to that of the parental strain. The cold-sensitive strain is highly mutable to a cytoplasmic petite when grown at 18°, or when grown at 28° in the presence of 4 mg/ml of chloramphenicol. Cold sensitivity is not observed in the conversion of promitochondria to mitochondria. We conclude that mitochondrial protein synthesis is required for maintaining the stability of the mitochondrial genome.
Peptide Chain Termination with Mammalian Release Factor
Authors: Goldstein J. L. , Beaudet A. L. , Caskey C. T.
Published: May 2006

We report a method for the
in vitro
study of peptide chain termination in mammals. A proteinaceous release factor has been isolated from rabbit reticulocyte extracts. This factor and a polyribonucleotide template containing the bases U and A stimulate the release of
N
-formylmethionine from mammalian [
N
-formylmethionyl-tRNA
f
·ribosome] intermediates. Our studies suggest that UAA is a terminator codon for mammalian cells.
Proton Magnetic Resonance Studies of
Chromatium
High-Potential Iron Protein
Authors: Phillips W. D. , Poe Martin , McDonald C. C. , Bartsch Robert G.
Published: May 2006

Contact-shifted nuclear magnetic resonances, arising from molecular paramagnetism, have been observed in both reduced and oxidized forms of the high-potential iron protein (HiPIP) isolated from
Chromatium
. Contact shifts of the reduced, formally diamagnetic form increase with temperature, indicating antiferromagnetic exchange coupling of the component iron atoms with thermal population of a magnetic state. In the oxidized form of HiPIP (formally S = 1/2), contact-shifted resonances attributed to the β-CH
2
groups of two cysteine residues display approximate Curie law behavior, while contact-shifted resonances assigned to the two other cysteine residues continue to exhibit a temperature dependence characteristic of antiferromagnetic exchange coupling. A cluster model for the redox center of
Chromatium
HiPIP that appears compatible with the PMR and preliminary x-ray results
4, 11
is discussed.
Glucocorticoid Inhibition of RNA Synthesis Responsible for Cleft Palate in Mice: A Model
Authors: Zimmerman Ernest F. , Andrew Floyd , Kalter Harold
Published: May 2006

A study was undertaken to elucidate the molecular mechanisms by which glucocorticoids induce cleft palate in mice. It was hypothesized that a compound such as triamcinolone acetonide inhibits mRNA synthesis; that this results later in depressed protein synthesis; and that the latter is ultimately responsible for slowed palate formation and cleft palate. Support for the model derives from the fact that the palatine shelves rise and fuse 3-4 days after the most sensitive time of administration of steroid; RNA synthesis was markedly inhibited 6-24 hr after its administration; and coadministration of cycloheximide partially reversed the tendency toward cleft palate formation.
Two Radiation-Induced Chromosomal Inversions in Mice (
Mus musculus
)
Authors: Roderick Thomas H. , Hawes Norman L.
Published: May 2006

Whole-body x-irradiation of male mice has produced presumptive paracentric inversions in 15 animals, as evidenced by high frequencies of first meiotic anaphase bridges. Two of the highest frequencies observed have been propagated through several generations and found to behave as dominant genes. Acentric fragments were observed associated with about 10% of the bridges. The first inversion, in linkage group XIII, has been designated
In
(
13
)
1Rk
, and the second, in linkage group XVII,
In
(
17
)
2Rk
. For
In
(
13
)
1Rk
, recombination was reduced between loci inside and outside the inverted segment.
A New Protein Synthesis Factor from
Escherichia coli
Authors: Kan Yuet Wai , Golini Fred , Thach Robert E.
Published: May 2006

A new factor that effects protein synthesis by
Escherichia coli
extracts was partially purified from the 1 M NH
4
Cl wash of
E. coli
ribosomes. This factor stimulates the binding of aminoacyl-tRNA to 30S ribosomes, and it increases the rate of synthesis of polyphenylalanine in the presence of 30S and 50S subunits.
Genetic Dissection of the
Drosophila
Nervous System by Means of Mosaics
Authors: Hotta Yoshiki , Benzer Seymour
Published: May 2006

Given a mutant having abnormal behavior, the anatomical domain responsible for the deficit may be identified by the use of genetic mosaicism. Individuals may be produced in which a portion of the body is mutant male while the rest is normal female. In such sex mosaics, or gynandromorphs, the division line between normal and mutant parts can occur in various orientations. Mutants of five different genes (cistrons) on the X-chromosome of
Drosophila melanogaster
, having various abnormalities in visual function, have been tested by this method. All of these have been found to be autonomous, i.e., a mutant eye always functions abnormally, regardless of the amount of normal tissue present elsewhere, indicating that the primary causes of the behavioral deficits in these mutants are within the eye.
Studies on Polynucleotides, C A Novel Joining Reaction Catalyzed by the T4-Polynucleotide Ligase
Authors: Sgaramella V. , van de Sande J. H. , Khorana H. G.
Published: May 2006

The polynucleotide ligase isolated from T4-infected
Escherichia coli
was previously shown to bring about repair of breaks in the single strands of bihelical DNA. The present work shows that the enzyme can also catalyze the joining of DNA duplexes at their base-paired ends. This novel reaction occurs when the deoxynucleoside at a 5′-end carries a phosphate group and the complementary deoxynucleoside opposite to it carries a 3′-hydroxyl group. The consequence is the lengthening of the original duplex to form dimers or oligomers depending upon whether one or both ends are base-paired.
Effect of Muscle Denervation on Growth of Transplanted Tumor in Mice
Authors: Batkin Stanley , Piette Lawrence H. , Wildman Ellen
Published: May 2006

A temporary retardation of transplanted Round Cell Neuroblastoma growth in the gastrocnemius muscle of mice was observed in 20% of the animals after denervation of the muscle. The tumor cells in these denervated animals showed structural alterations and deterioration in function. These altered cells when mixed with associated denervated muscle tissue, to which was added fresh tumor, produced a higher percentage of retardation upon subsequent transplants in innervated muscle.
Protein Chain-Initiating Methionine tRNAs in Chloroplasts and Cytoplasm of Wheat Leaves
Authors: Leis Jonathan P. , Keller Elizabeth B.
Published: May 2006

The role of methionine in protein chain initiation in wheat has been studied. Two chain-initiating methionine tRNAs have been found. One of these is located in the cytoplasm of the wheat cell. This methionyl-tRNA is not formylated by wheat extracts and appears to function in protein chain initiation in the cytoplasm without prior formylation. The other initiating tRNA is from chloroplasts. This methionyl-tRNA is formylated by a transformylase present in wheat extracts and functions in chain initiation in chloroplasts as formylmethionyl-tRNA.
Embedding Trees in the Rationals
Authors: Baumgartner J. , Malitz J. , Reinhardt W.
Published: May 2006

An example is presented of a simple algebraic statement whose truth cannot be decided within the framework of ordinary mathematics, i.e., the statement is independent of the usual axiomatizations of set theory. The statement asserts that every tree-like ordering of power equal to or less than the first uncountable cardinal can be embedded homomorphically into the rationals.
Steroidal Free Radicals as Possible Intermediates in the Biosynthesis of C
19
-△
16
-Steroids
Authors: Lippman Violet , Lieberman Seymour
Published: May 2006

Treatment of deoxycorticosterone with reagents that abstract a hydrogen atom from the C-21-hydroxyl group leads to the formation of androsta-4,16-dien-3-one.
In vitro
incubations of [1,2-
3
H]deoxycorticosterone with homogenates of boar testis tissue produce the tritiated dienone. This reaction can be formulated as an abstraction of hydrogen from the C-21-hydroxyl group to form a C-21-alkoxy radical, followed by a 1,5-H·shift from the C-16 atom and β-scission of the C-16-alkoxy radical leading to the loss of a C
2
fragment (C-20 and C-21) with the formation of the double bond between C-16 and C-17.

Both the chemical model and the
in vitro
experiment support further the thesis [Lieberman, S., L. Bandy, V. Lippman, and K. D. Roberts,
Biochem. Biophys. Res. Commun.
, 34, 367 (1969)] that biosynthetic reactions in which molecular oxygen reacts with steroids (for example, side-chain cleavage or hydroxylation) involve steroidal free radicals.
Specificity of mRNA Binding Factor in Eukaryotes
Authors: Heywood Stuart M.
Published: May 2006

It has been shown previously that ribosomal factors removed from chick muscle ribosomes by a high salt wash are required for both the binding of muscle mRNA to ribosomes and mRNA-directed synthesis of myosin on reticulocyte ribosomes. These factors can be separated into several components on DEAE-cellulose. A factor eluting between 0.18 and 0.25 M KCl is responsible for binding mRNA to the ribosome. This binding factor shows specificity in the recognition of mRNA, as has been demonstrated by the preferential binding of muscle and globin mRNA to ribosomes which contain their respective binding factors. Similarly, globin mRNA is preferentially translated when reticulocyte factors are present on the ribosome.
DNA of Vegetative Bacteriophage Lambda, VI Electron Microscopic Studies of Replicating Lambda DNA
Authors: Kiger John A. , Sinsheimer Robert L.
Published: May 2006

Electron micrographs of replicating lambda DNA molecules, during the period of progeny-particle DNA formation, show single-tailed circular structures. The tails are, predominantly, shorter than one viral genome.
Further Studies of the Whitetop Cloud-Seeding Experiment
Authors: Lovasich Jeanne L. , Neyman Jerzy , Scott Elizabeth L. , Wells Marcella A.
Published: May 2006

By means of two stratifications of experimental days of the Whitetop Project—into categories E and W and into categories air mass and frontal—the effects of cloud seeding on precipitation downwind, upwind, and to the sides, up to 180 miles from the seeding line, were investigated. No significant effects were found for W and frontal days. On the other hand, for E and airmass days, significant and highly significant apparent effects of seeding were found in all directions and in areas at distances up to 180 miles. All these significant apparent effects are negative, the largest of them indicating that seeding reduced precipitation to one quarter of its unseeded value.
Transcription of Nonrepeated DNA in Neonatal and Fetal Mice
Authors: Gelderman A. H. , Rake A. V. , Britten R. J.
Published: May 2006

The transcription of nonrepeated DNA sequences was measured by hybridization of RNA from neonatal and fetal mice to mouse DNA using three different techniques. The measurements indicate that a large part (about 70%) of the rapidly-labeled fetal RNA is transcribed from nonrepeated DNA sequences. It appears that more than 12% of the single-copy DNA sequences are represented in the RNA of newborn mice.
Esterase Polymorphism in the Butterfly
Hemiargus isola
Stability in a Variable Environment
Authors: Burns John M. , Johnson F. M.
Published: May 2006

A dimeric esterase of a lycaenid butterfly shows rich, electrophoretically-detectable variation in natural populations in Texas. This isozyme variation is controlled by multiple alleles at an autosomal locus (
Es-d
). In each population sampled there are 9-14 alleles, two of which (
Es-d
100
and
Es-d
80
) predominate and form about 84% of the gene pool. Against the background of numerous rarer alleles, their frequencies are notably stable (about 65% and 19%, respectively) in ecologically variable space and time. Although adults (especially females) are capable of genetically effective dispersal, environmental heterogeneity within each locality is thought to be the prime factor maintaining the polymorphism.
Unexpectedly Large Size of Globin Messenger Ribonucleic Acid
Authors: Gaskill Pauline , Kabat David
Published: May 2006

The globin messenger RNA of rabbit reticulocytes is identified on the basis of its presence in polysomes, absence from single ribosomes, and sedimentation coefficient of 9 S. Analysis of this RNA by electrophoresis in polyacrylamide gels provides evidence that its size is unexpectedly large (approximately 650 nucleotides) for a messenger coding for the 141 and 146 amino acids of a globin polypeptide.

Reticulocyte RNA molecules were labeled
in vivo
with [
32
P]orthophosphate. Globin messenger RNA and transfer RNA appear to be synthesized late in erythropoiesis, whereas ribosomal RNA and 5S RNA are synthesized at the beginning stages of cytodifferentiation. At least one fragment of ribosomal RNA accumulates in erythrocytes in the terminal stages of maturation.
Production of Albumin and Other Serum Proteins by Clonal Cultures of Normal Human Liver
Authors: Kaighn M. Edward , Prince Alfred M.
Published: May 2006

Clonal cell strains have been isolated from normal human liver. These cells, while resembling fibroblasts morphologically, function as hepatocytes, as shown by their ability to synthesize and secrete an antigen identical to human serum albumin. Human diploid and aneuploid cell lines from nonliver sources do not exhibit this property. The spectrum of serum proteins synthesized varied from clone to clone and cell line to cell line.
C
55
-Isoprenoid Alcohol Phosphokinase: An Extremely Hydrophobic Protein from the Bacterial Membrane
Authors: Sandermann Heinrich , Strominger Jack L.
Published: May 2006

C
55
-isoprenoid alcohol phosphokinase, a butanol-soluble enzyme from the membrane of
Staphylococcus aureus
, has been purified to homogeneity by the inclusion of organic solvents in all of the techniques used. By polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, the enzyme is a single polypeptide chain of molecular weight 17,000. The amino-acid analysis reveals an unusually high content of nonpolar amino acids (58%), the largest amount so far reported in any protein. When equilibrated in butanol-water, enzyme apoprotein is found in the butanol layer. The influence of sodium chloride indicates that the lipid requirement of the enzyme is nonelectrostatic in nature.
Evidence for Position-Effect Suppression of the Ribosomal RNA Cistrons in
Drosophila melanogaster
Authors: Baker William K.
Published: May 2006

Unambiguous evidence is presented that two
X
-chromosome inversions produce lethality in
X/O
males because of position-effect suppression of genes in the basal heterochromatin. The data support the hypothesis that the ribosomal RNA cistrons are the genes suppressed. There is evidence for a region in the
X
basal heterochromatin that may act as a regulator of rDNA activity.
Amino-Acid Sequences of Light Chains of a Rabbit Anti-
p
-Azobenzoate Antibody
Authors: Appella E. , Chersi A. , Roholt O. A. , Pressman D.
Published: May 2006

Half-cystine peptic peptides representing the intrachain disulfide bonds of the light chain from an apparently homogeneous rabbit anti-
p
-azobenzoate antibody were isolated in good yields after reduction and alkylation with [
14
C]iodoacetate, and their sequences were determined. The sequence of the first 21 amino-terminal residues was also determined. The good yields of these peptides, the fact that no variants of any of them were found, and the cleanness of the amino-terminal sequence determination confirm the high degree of homogeneity of this light-chain preparation. Previous evidence for the homogeneity of the light chain includes the appearance of only a single band upon analysis by disc electrophoresis, a relatively unique amino-acid composition, and a simple tryptic peptide map. The whole antibody shows a homogeneity of the hapten-binding constant. The antigen used in the present work is complex, since the attached hapten groups are in a large variety of environments, particularly since the carrier is a heterogeneous mixture of globulins. The very limited heterogeneity of the antibodies found in this case would appear to depend on the stimulation of only a few of the cells capable of producing antibody against a given hapten, rather than on a structural identity of the environment around each individual hapten group that is located on the antigen molecule.
Spin-Label Electron Spin Resonance Study of the Lipid-Containing Membrane of Influenza Virus
Authors: Landsberger Frank R. , Lenard John , Paxton John , Compans Richard W.
Published: May 2006

The organization of the lipid-containing membrane of influenza virus has been studied by the use of three different lipid spin labels, and the results are compared with a parallel study on human erythrocyte ghosts. The lipid phase of the viral membrane is slightly more rigid than that of the erythrocyte ghosts. The data suggest that the viral lipid is arranged in a bilayer. The data suggest that the viral lipid is arranged in a bilayer. The glycoprotein spikes covering the viral membrane were specifically removed by proteases, and no alteration in the environment of any of the three spin labels was detected. This suggests that the spikes are not involved in determining the organization of the lipid bilayer.
RNA Polymerases of Maize: Nuclear RNA Polymerases
Authors: Strain Gustave C. , Mullinix Kathleen P. , Bogorad Lawrence
Published: May 2006

Two DNA-dependent RNA polymerases of nuclear origin have been purified from leaves of
Zea mays
. The two enzymes can be separated on DEAE-cellulose columns. Enzymes I and II are eluted with 0.08 and 0.20 M (NH
4
)
2
SO
4
, respectively. Both enzymes prefer maize nuclear DNA as a template; they are also more active in the presence of Mg
++
than Mn
++
and are inhibited by (NH
4
)
2
-SO
4
or KCl. Neither enzyme is inhibited by rifamycin SV. Enzyme II is strongly inhibited by α-amanitin, whereas enzyme I is not significantly affected. Their ability to use native and denatured DNA as templates varies according to the extent and method of purification of the polymerase. Furthermore, enzyme II can be resolved by DEAE-chromatography or glycerol-gradient centrifugation into two components, one of which prefers native DNA, while the other prefers denatured DNA.
Repression of the Overproduction of Porphyrin Precursors in Acute Intermittent Porphyria by Intravenous Infusions of Hematin
Authors: Bonkowsky H. L. , Tschudy D. P. , Collins A. , Doherty J. , Bossenmaier I. , Cardinal R. , Watson C. J.
Published: May 2006

In a patient with a severe attack of acute intermittent porphyria, hematin given intravenously caused marked diminution of serum δ-aminolevulinic acid and porphobilinogen. The decline of aminolevulinate was more rapid than that of porphobilinoge. After 2 days of hematin administration, about 5 days were required for δ-aminolevulinic acid, and 11 days for porphobilinogen to return to the concentrations that were detected before treatment. Urinary excretion of both compounds also decreased after hematin administration. Considerable amounts of porphobilinogen were also found in the cerebrospinal fluid of the patient.
Glucose and the Metabolism of Adenosine 3′:5′-Cyclic Monophosphate in
Escherichia coli
Authors: Peterkofsky Alan , Gazdar Celia
Published: May 2006

Measurements of adenosine 3′:5′-cyclic monophosphate (cAMP) concentrations have been made in
Escherichia coli
under various conditions. Different strains of
E. coli
accumulate different extracellular concentrations of cAMP (0.2-4 μm) at stationary phase. Mutation at the RNA control locus does not affect the accumulation pattern. Growth of the bacteria in minimalsalts medium leads to a greater accumulation of cAMP than growth in nutrient broth. Partition studies show that essentially all of the cAMP that is accumulated is found in the medium rather than in the cells. Kinetic studies show that most of the cAMP is formed coincidentally with exhaustion of glucose from the medium. Growth on high concentrations of glucose leads to inhibition of cAMP formation. Other carbon sources cannot substitute for glucose in this inhibitory effect. Measurements of enzyme activities indicate that glucose suppression of cAMP formation cannot be accounted for by a decreased activity of adenylate cyclase or an increased activity of cAMP phosphodiesterase (EC 3.1.3.7).
Inactivation of D-Alanine Carboxypeptidase by Penicillins and Cephalosporins Is Not Lethal in
Bacillus subtilis
Authors: Blumberg Peter M. , Strominger Jack L.
Published: May 2006

The D-alanine carboxypeptidase of
Bacillus subtilis
is a particulate enzyme that is irreversibly inactivated by penicillins and cephalosporins. However, the lethal concentrations of these antibiotics are not the same as those that inhibit enzymatic activity
in vitro
. 6-Aminopenicillanic acid inactivates at least 95% of the enzyme at nonlethal concentrations. Conversely, cephalothin is lethal at concentrations that do not inactivate the enzyme. Experiments with intact, growing cells confirm the results obtained
in vitro
. Therefore, a killing site distinct from the carboxypeptidase must be postulated.
Determination of the Gene Sequence of Poliovirus with Pactamycin
Authors: Summers D. F. , Maizel J. V.
Published: May 2006

By examination of the virus-specific polypeptides formed after the addition of pactamycin, an inhibitor of protein chain initiation, to infected cells, it has been possible to tentatively locate the virus coat proteins at the amino terminus of the large, virus-specific protein precursor, and, therefore, to assign the coat protein cistron to the 5′ end of the RNA.
Glucose Transfer from Dolichol Monophosphate Glucose: The Product Formed with Endogenous Microsomal Acceptor
Authors: Behrens Nicolas H. , Parodi Armando J. , Leloir Luis F.
Published: May 2006

The product formed by incubation of dolichol monophosphate glucose with liver microsomes was studied. It is insoluble in most solvents, but is soluble in a chloroform-methanol mixture with a high content of water. Treatment with ammonia gave rise to the formation of a water soluble, negatively charged compound of molecular weight 3550. The negative charge could be removed by treatment with phosphatase.

Acid hydrolysis of the original compound led to the liberation of an uncharged, water-soluble compound (molecular weight 3550). Acetolysis of the latter gave rise to the formation of a series of products, which appeared to be oligosaccharides when chromatographed on paper or silica plates. The original substance behaved like a polyprenol pyrophosphate when chromatographed on DEAE-cellulose.

Molecular weight measurements of the deoxycholate inclusion compound gave a value of 14,300, while dolichol monophosphate glucose under the same conditions gave 11,300.

It is tentatively suggested that the compound is dolichol joined through a phosphate or pyrophosphate bridge to an oligosaccharide containing about 20 monosaccharide residues.
The Light Reactions of Photosynthesis
Authors: Arnon Daniel I.
Published: May 2006

Historically, the role of light in photosynthesis has been ascribed either to a photolysis of carbon dioxide or to a photolysis of water and a resultant rearrangement of constituent atoms into molecules of oxygen and glucose (or formaldehyde). The discovery of photophosphorylation demonstrated that photosynthesis includes a light-induced phosphorus metabolism that precedes, and is independent from, a photolysis of water or CO
2
. ATP formation could best be accounted for not by a photolytic disruption of the covalent bonds in CO
2
or water but by the operation of a light-induced electron flow that results in a release of free energy which is trapped in the pyrophosphate bonds of ATP.

Photophosphorylation is now divided into (
a
) a non-cyclic type, in which the formation of ATP is coupled with a light-induced electron transport from water to ferredoxin and a concomitant evolution of oxygen and (
b
) a cyclic type which yields only ATP and produces no net change in the oxidation-reduction state of any electron donor or acceptor. Reduced ferredoxin formed in (
a
) serves as an electron donor for the reduction of NADP by an enzymic reaction that is independent of light. ATP, from both cyclic and noncyclic photophosphorylation, and reduced NADP jointly constitute the assimilatory power for the conversion of CO
2
to carbohydrates (3 moles of ATP and 2 moles of reduced NADP are required per mole of CO
2
).

Investigations, mainly with whole cells, have shown that photosynthesis in green plants involves two photosystems, one (System II) that best uses light of “short” wavelength (λ < 685 nm) and another (System I) that best uses light of “long” wavelength (λ > 685 nm). Cyclic photophosphorylation in chloroplasts involves a System I photoreaction. Noncyclic photophosphorylation is widely held to involve a collaboration of two photoreactions: a short-wavelength photoreaction belonging to System II and a long-wavelength photoreaction belonging to System I. Recent findings, however, indicate that noncyclic photophosphorylation may include two short-wavelength, System II, photoreactions that operate in series and are joined by a “dark” electron-transport chain to which is coupled a phosphorylation site.
ATP-Catalyzed Preconditioning of Phosphofructokinase
Authors: Alpers Joseph B. , Paulus Henry , Bazylewicz Gregory A.
Published: May 2006

Phosphofructokinase (EC 2.7.1.11) is subject to inactivation (at pH values below 6) and reactivation (at alkaline pH) to forms that correspond, respectively, to immature and mature conformational states. ATP is one of several ligands that facilitate the reactivation process, which we have termed preconditioning (1, 2). Evidence is presented that the role of ATP is a catalytic one: (
a
) the continued presence of ATP is not required to maintain the reactivated state; and (
b
) conditions can be found under which ATP catalyzes both activation and inactivation. The findings support the concept that a small molecule can catalyze changes in the conformation of a macromolecule.

The correct refolding of phosphofructokinase competes with the folding of the enzyme to an inactive species. Thus, the effect of ATP on reactivation is reflected in enhancement not only of the
rate
, but also of the
extent
, of reactivation. That is, the ligand subjects the system to an irreversible commitment.
The Structure of Chromatin
Authors: Mirsky Alfred E.
Published: May 2006

The DNA in chromatin of isolated thymus nuclei, and in two different preparations of deoxyribonucleoprotein extracted from chromatin, has been digested with DNase. By variation of the time of reaction and the concentration of enzyme, and by comparison of the action of the enzyme on (protein-free) DNA with its action on DNA complexed with protein in chromatin and deoxyribonucleoprotein, it was found that most, if not all, of the DNA is linked to protein. The linkage is loose, as shown by the fact that all the DNA is accessible to the enzyme; however, the wide variations in accessibility in a given complex show that the looseness of the DNA-protein link varies considerably. Accessibility of DNA in one type of deoxyribonucleoprotein preparation is greater than it is in chromatin, while in the other type it is less than in chromatin.
On the Similarity Between the tRNAs of Organelles and Prokaryotes
Authors: Fairfield S. A. , Barnett W. Edgar
Published: May 2006

Fluorescence studies with organelle transfer RNAs separated from their cytoplasmic counterparts revealed that phenylalanine tRNA from
Euglena
chloroplasts or
Neurospora
mitochondria does not contain a fluorescent “base Y.” In contrast, cytoplasmic phenylalanine tRNA from
Euglena
and cytoplasmic tRNA from
Neurospora
were found to contain fluorescent bases. The fluorescence-emission spectra of
Neurospora
cytoplasmic tRNAs and those of the related ascomycete
Saccharomyces cerevisiue
were observed to be quite different. The results support the generalization that eukaryotic tRNAs contain a fluorescent base, but indicate that their respective organelle tRNAs do not. They also indicate a striking parallelism between organelle and prokaryotic tRNAs.
Molecular Structures of DNA-Dependent RNA Polymerases (II) from Calf Thymus and Rat Liver
Authors: Weaver R. F. , Blatti S. P. , Rutter W. J.
Published: May 2006

DNA-dependent RNA polymerase II has been purified to high specific activity and apparent homogeneity from both calf thymus and rat liver. Two form II enzymes are present in rat-liver preparations, one with the molecular structure [(190,000)
1
(150,000)
1
(35,000)
1
(25,000)
1
], the other with a molecular structure of [(170,000)
1
(150,000)
1
(35,000)
1
(25,000)
1
] (molecular weights are within ±5% but the absolute values are approximate). Inclusion of a proteolytic inhibitor during the isolation procedure decreases the proportion of the molecule containing the 170,000 subunit. Calf-thymus RNA polymerase preparations typically exhibit four components on polyacrylamide gels that contain sodium dodecyl sulfate, with an apparent molecular structure of [(190,000)
1
(150,000)
1
(35,000)
1
(25,000)
1
]. In addition, some calf-thymus polymerase II preparations contain small quantities of the [(170,000)
1
(150,000)
1
(35,000)
1
(25,000)
1
] species; the quantity of this species may also be increased from less than 5% in the normal preparation to at least 40% in an “aged” preparation. Thus, the 170,000 subunit may be derived from the 190,000 subunit in both tissues. Until unequivocal evidence is obtained on this point, however, the possibility that the large subunits are unique species should not be eliminated. The general structural similarity of the eukaryotic RNA polymerase II with that of the prokaryotic polymerase suggests that the modes of action and regulation may be analogous.
Visualization of Single Heavy Atoms by Dark Field Electron Microscopy
Authors: Henkelman R. M. , Ottensmeyer F. P.
Published: May 2006

Dark field electronmicrographs of atoms of palladium, iodine, platinum, osmium, and uranium in model compounds have been obtained. Statistical analyses and a series of blind tests demonstrate the validity of the results. Moreover, optical density measurements of the images indicate that the observed relative scattering cross-sections of these atoms agree well with the theoretical cross-sections calculated from a Thomas-Fermi-Dirac model of the atom.