bluuebunny/crossref_metadata_2025 huggingface dataset:
Association of ATP: Glutamine Synthetase Adenylyltransferase Activity with the P
I
Component of the Glutamine Synthetase Deadenylylation System
Authors: Anderson Wayne B. , Hennig S. Barbara , Ginsburg Ann , Stadtman E. R.
Published: May 2006

Regulation of glutamine synthetase (EC 6.3.1.2) in
Escherichia coli
is mediated by adenylylation and deadenylylation of the enzyme. The present studies show that one protein is a common component of both the adenylylation and deadenylylation systems. Thus, the ATP:glutamine synthetase adenylyltransferase, which catalyzes adenylylation of glutamine synthetase, and one of the two proteins required for deadenylylation (the P
I
protein) are inseparable by a variety of fractionation procedures. The adenylyltransferase and P
I
-deadenylylating activities behave as a single protein upon filtration through Agarose A 0.5 gel, and during chromatography on DE32 cellulose and hydroxyapatite columns. They migrate as a single protein band during electrophoresis on polyacrylamide gel and have identical susceptibilities to heat inactivation. These data indicate that the adenylyltransferase and the P
I
-deadenylylation activity are associated with the same protein complex.
Identification of the Cytokinin-Active Ribonucleosides in Pure
Escherichia coli
tRNA Species
Authors: Bartz J. , Söll D. , Burrows W. J. , Skoog F.
Published: May 2006

The distribution of the two cytokinin-active ribonucleosides 6-(3-methyl-2-butenylamino)-9-β-D-ribofuranosylpurine (1) and 6-(3-methyl-2-butenylamino)-2-methylthio-9-β-D-ribofuranosylpurine (2) in tRNA
Phe
, tRNA
UUG
Leu
, tRNA
UCR
Ser
, tRNA
Tyr
, tRNA
Cys
, and tRNA
2
Trp
from stationary phase
Escherichia coli
has been studied. Compound 2 predominated in all these species except tRNA
Phe
, in which compound 1 was greatly in excess. Compound 1 was present in relatively small amounts in tRNA
UUG
Leu
, tRNA
Cys
, and tRNA
2
Trp
, and was not detected in tRNA
UCR
Ser
and tRNA
Tyr
. Cells from the early logarithmic phase had the highest cytokinin content in their tRNA. Stationary phase tRNA had a slight increase in the amount of 1, which may be explained by the appearance of the new tRNA
Phe
. No differences were observed between the chromatographic patterns of tRNAs from early-, mid-, and latelogarithmic phases.
Law of Conservation of the Capital-Output Ratio
Authors: Samuelson Paul A.
Published: May 2006

Just as simple harmonic motion, definable by a variational condition, δ [unk] (½
ẋ
2
- ½
x
2
)
dt
= 0, has motions which must conserve the sum of kinetic and potential energies, ½
ẋ
2
+ ½
x
2
≅ constant, so in a neoclassical von Neumann economy, where all output is saved to provide capital formation for the system's growth, it will be true that there exists a conservation law—namely the constancy along any intertemporally-efficient motion of the capital-output ratio Σ

P
t
j
K
t
j

/Σ

P
t
j
K
t
j

. This is derived as an „energy” integral of a time-free integrand
1
in an optimal-control problem of variational type.
Photodestruction of Chloroplast Ultrastructure by Red Light: Location of Chlorophyll
Authors: Walne Patricia L. , Haber Alan H. , Triplett Larry L.
Published: May 2006

A lethal dose (1 Mrad) of gamma rays was given to wheat leaf tissue to restrict migration of the energy of red light photoexcitation to the photosynthetic pigment system. This dose of gamma radiation had no apparent effect on chloroplast ultrastructure in tissue that received no illumination. Subsequent illumination with red light, used to induce chlorophyll-sensitized photodestruction of ultrastructure, permitted inferences about the location of chlorophyll within the chloroplast. The red light produced extensive disruption in chloroplasts but not in any other cellular organelles. The sequence of events in this photodestruction was different from that which occurs when chloroplasts are destroyed by methods that do not involve illumination. The red light caused peculiar abnormalities only in the internal lamellar system of the chloroplast and not in the envelope or any other regions. These findings support other studies which suggest that chlorophyll is located exclusively in grana and stroma lamellae.
A Specific Competitive Inhibitor of Angiotensin II
Authors: Marshall Garland R. , Vine William , Needleman Philip
Published: May 2006

A peptide analog, [4-phenylalanine, 8-tyrosine]-angiotensin II, was prepared by solid phase peptide synthesis and its structure confirmed. The compound was found to be a potent inhibitor of angiotensin II
in vitro
(isolated rat uterus strips) and
in vivo
(rat blood pressure). The analog was found to be highly specific and did not inhibit the action of a number of other peptides and spasmogenic compounds.
Evolution and the Need for Ascorbic Acid
Authors: Pauling Linus
Published: May 2006

Ascorbic acid differs from other vitamins in that an exogenous source is required by only a few animal species. It is pointed out that this fact indicates that the amount contained in a diet of raw natural plant food is less than the optimum intake, corresponding to the best health. This argument leads to the conclusion that the optimum daily intake is about 2.3 g or more, for an adult with energy requirement 2500 kcal day
-1
.
Translational Repression in the Arginine System of
Escherichia coli
Authors: McLellan William L. , Vogel Henry J.
Published: May 2006

Translation of bacterial mRNA, divorced from transcription, has been obtained for enzymes of arginine synthesis; evidence has been acquired for repression by arginine at the level of translation. mRNAs for acetylornithinase and ornithine transcarbamylase were accumulated by arginine starvation of
argR
+
and
argR
-
arginine auxotrophs derived from
Escherichia coli
K12. Further transcription was inhibited with rifampicin or miracil D, and enzyme formation was measured in the presence of either an excess of, or a restricted supply of, arginine. For the
argR
+
strain 961, little mRNA was found without starvation; for the
argR
-
strain 977, a considerable amount of mRNA was demonstrated even without starvation. There was relatively little translation for the
argR
+
strain, but not for the
argR
-
strain, in the presence of excess arginine, apparently due to an accelerated degradation of mRNA in the
argR
+
strain under repressive conditions.
Suppression of Immunoglobulin G Synthesis as a Result of Antibody-Mediated Suppression of Immunoglobulin M Synthesis in Chickens
Authors: Kincade Paul W. , Lawton Alexander R. , Bockman Dale E. , Cooper Max D.
Published: May 2006

Development of heterogeneity of immunoglobulin classes has been investigated in the chicken by studying the effects of antibody-mediated suppression of IgM synthesis. Treatment of 13-day embryos with purified goat antibodies to IgM resulted in the elimination of IgM-containing cells from the bursa of Fabricius of 16- and 19-day embryos. When combined with bursectomy at hatching, administration of anti-IgM
in ovo
suppressed the synthesis not only of IgM but also of IgG. A number of experimental birds lacked detectable circulating immunoglobulins, plasma cells, and germinal centers when killed at 10 weeks of age. Contrasting results were obtained when IgM synthesis was suppressed
after
bursectomy at hatching. Birds so treated produced little or no IgM but synthesized normal amounts of IgG. The results suggest that, within the bursal environment, IgG-producing cells arise exclusively from cells that previously synthesized IgM. A model for generation of antibody variability is presented.
Immunofluorescent Evidence for Cellular Control of Synthesis of Variable Regions of Light and Heavy Chains of Immunoglobulins G and M by the Same Gene
Authors: Levin A. S. , Fudenberg H. H. , Hopper J. E. , Wilson S. K. , Nisonoff A.
Published: May 2006

Two distinct paraproteins (IgG
2
-K and IgM-K) from one patient shared identical light chains and significant portions of the variable regions of the heavy chains. Idiotypic determinants on the IgG and IgM molecules were shared. Earlier studies, using class-specific antisera, showed that these paraproteins were produced by two different populations of cells. The present study, using rhodamine and fluorescein conjugates of the anti-idiotype antisera, demonstrates that all plasma cells that contain immunoglobulin, whether IgG or IgM, stained with anti-idiotype antisera; this occurred irrespective of whether the antisera were made originally against the patient's IgG or IgM. This, plus previous data, indicates that both populations of cells share genetic information for the constant and variable regions of light chains and significant portions of the heavy-chain genes. These, and other cited data, strongly suggest the occurrence of a switch-over from IgM to IgG synthesis in the same cell during the course of the normal immune response.
Genes for Neuronal Properties Expressed in Neuroblastoma × L Cell Hybrids
Authors: Minna John , Nelson Phillip , Peacock John , Glazer Devera , Nirenberg Marshall
Published: May 2006

Neuroblastoma cells with electrically excitable membranes were fused with electrically passive L cells having a hitherto undescribed electrical marker. Hybrid cells, examined 10-40 generations after fusion, were found to be electrically excitable. The results show that at least a part of the genetic information for neuron differentiation can be functionally expressed in N × L hybrid cells. Evidence for the regulation of action potential components was also found.
Lacunarity for Compact Groups
Authors: Edwards Robert E. , Hewitt Edwin , Ross Kenneth A.
Published: May 2006

Let
G
be a compact Abelian group with character group X. A subset Δ of X is called a [unk]

q

set (1 <
q
< ∞) if for all trigonometric polynomials
f
= [unk]

k
=1

n

α

k

χ

k

(χ
1
,...,χ

n

[unk] Δ) an inequality ∥
f
∥

q

[unk] [unk]∥
f
∥
1
obtains, where [unk] is a positive constant depending only on Δ. The subset Δ is called a Sidon set if every bounded function on Δ can be matched by a Fourier-Stieltjes transform. It is known that every Sidon set is a [unk]

q

set for all
q
. For
G = T
, X =
Z
, Rudin (
J. Math. Mech., 9
, 203 (1960)) has found a set that is [unk]

q

for all
q
but not Sidon. We extend this result to all infinite compact Abelian groups
G:
the character group X contains a subset Δ that is [unk]

q

for all
q
, 1 <
q
< ∞, but Δ is not a Sidon set.
Instabilities of High Temperature Superconductors
Authors: Matthias B. T. , Corenzwit E. , Cooper A. S. , Longinotti L. D.
Published: May 2006

We have observed the transition temperature of both the cubic and tetragonal phases of several high-temperature β-W superconductors. The instability of the cubic lattice appears to be characteristic of high-temperature superconductors.
Partial Enzyme Aggregates Formed by Pleiotropic Mutants in the
arom
Gene Cluster of
Neurospora crassa
Authors: Case Mary E. , Giles Norman H.
Published: May 2006

Molecular weights of enzymically active
arom
aggregates produced by pleiotropic and various
arom-1
mutants of
Neurospora crassa
have been estimated by sucrose density gradient centrifugation. In contrast to most single-gene mutants (which produce intact
arom
multienzyme aggregates of normal molecular weight— about 230,000), pleiotropic mutants that lack two or more of the five enzyme activities in the
arom
aggregate produce partial
arom
aggregates of molecular weights ranging from about 60,000 to about 85,000. In addition, certain
arom-1
mutants are pleiotropic in producing
arom
aggregates of about half the normal molecular weight. Experiments with heterocaryons, as well as with mixtures of extracts from various mutants, have provided evidence concerning the presence or absence of interactions (as detectable molecular hybridization) between different
arom
aggregates. An evaluation has been made of the relation between the genetic location of particular mutants within the
arom
gene cluster and the size and enzymic content of the
arom
aggregates they produce. Interpretations concerning the molecular organization of the
arom
multienzyme aggregate in
N. crassa
are presented.
3,6-Anhydroglucosaminyl Formation in Mucopolysaccharides
Authors: Sampson Phyllis , Meyer Karl
Published: May 2006

Treatment of keratosulfates with alkali leads to the formation of 3,6-anhydroglucosaminyl groups in high yield. A similar reaction takes place with heparin and heparitin sulfate, though to a lesser extent. The anhydrosugar was isolated and compared with synthetic 3,6-anhydroglucosamine. The isolated compounds were identical in ion exchange chromatography in the amino acid analyzer and on Dowex 50 H
+
eluted with dilute HCl. The spectra of the isolated and synthesized anhydrosugar were identical in infrared and nuclear magnetic resonance. Derivatized compounds were identical in gas-liquid chromatography and mass spectroscopy. The peracetylated compound isolated from keratosulfate gave the nuclear magnetic reasonance and fragmentation pattern of the postulated compound. The reaction is expected to be useful in structural studies of hexosamine-containing polymers.
Activation and Isolation of Hamster-Specific C-Type RNA Viruses from Tumors Induced by Cell Cultures Transformed by Chemical Carcinogens
Authors: Freeman Aaron E. , Kelloff Gary J. , Gilden Raymond V. , Lane William T. , Swain Ansel P. , Huebner Robert J.
Published: May 2006

Cell cultures of Syrian hamster embryo were treated for 7 days with selected chemicals. Certain cultures were morphologically transformed by three different chemical preparations and yielded cell lines that subsequently produced malignant tumors in hamsters. Although the cell lines were negative for infectious virus before inoculation into animals, hamster-specific C-type RNA virus was isolated from tumors or from cell lines derived from the tumors. Since infectious C-type viruses are usually not demonstrable in hamster tissues of normal or tumor origin, we conclude that the chemical treatment and activation of the viruses are related events.
On the Process of Cellular Division in
Escherichia coli:
Replication of the Bacterial Chromosome Under Control of Prophage P2
Authors: Lindahl Gunnar , Hirota Yukinori , Jacob François
Published: May 2006

The temperature-sensitive mutant CRT46 of
Escherichia coli
K12 is unable to initiate new rounds of DNA replication at 42°C. Mutants of bacteriophage P2 have been isolated, which, in the prophage state, allow mutant CRT46 to grow at 42°C. The lysogenic bacteria that grow at 42°C are apparently replicating under the control of prophage P2, which substitutes for the bacterial initiation system. The ability of prophage P2 cause this suppression phenomenon depends on the position of the prophage on the bacterial chromosome. Those lysogenic strains that are able to grow at 42°C all carry the prophage close to
metE
. The P2 mutants that allow CRT46 to grow at 42°C have insertions in the early region of the P2 genome. The suppression requires the
cis
-acting protein formed by gene A of P2.
Bioelectric Responses of the Echinoderm Egg to Fertilization
Authors: Steinhardt R. A. , Lundin L. , Mazia D.
Published: May 2006

The fertilization reaction of echinoderm eggs (
Lytechinus pictus
, a sea urchin, and
Dendraster excentricus
, a sand dollar) was followed with intracellular electrodes. Membrane potential and K
+
activity were recorded.

The unfertilized egg of
Lytechinus
has a membrane potential of -8 mV, inside negative. Within 5 sec after the addition of sperm, a
fertilization action potential
develops, going to +10 mV, inside positive. The time from the initial depolarization to a return to the original -8 mV is 120-150 sec. The repolarization continues until a potential of -10 to -14 mV is reached, at which point it pauses for 3-4 min. At 6-8 min after fertilization, a further and relatively rapid hyperpolarization begins, going to -60 to -65 mV by 15-25 min after fertilization and remaining constant at these values.

The membrane potential of the unfertilized egg appears to depend on a general permeability to anions. The fertilization action potential seems to reflect a prolonged influx of sodium. The final depolarization to -60 mV is attributable to the development of potassium conductance.

Simultaneous measurements with a K
+
ion-selective electrode gives constant readings of about 240 mM K
+
in the unfertilized eggs throughout the fertilization process.

Similar results were obtained with
Dendraster
eggs. The resting potential of the unfertilized eggs was -7 mV; the action potential on activation attained +18 mV; the repolarization paused at -16 to -24 mV and the final potential attained was -70 mV. The electrical changes after fertilization with spermatozoa or activation with Pronase were identical.
Theoretical Aspects of Orbital Steering
Authors: Dafforn A. , Koshland D. E.
Published: May 2006

A calculation based on transition-state theory leads to the conclusion that rate accelerations of 10
3
-10
5
could be achieved in an optimally oriented reaction relative to a similar randomly oriented bimolecular reaction. This factor is obtained by the use of partition functions of simplified systems and is based on contributions to rotational and vibrational entropy from reasonable transition states. A simple harmonic oscillator calculation leads to a similar conclusion for series of intramolecular reactions. Although the uncertainty in theoretical calculations of this type is considerable, the results add support to the conclusion based on experimental studies that orientation factors can play a very significant role in the catalytic power of enzymes.
The Stability Theory of Nonpolynomial Kinetics
Authors: Nazarea Apolinario D. , Rice Stuart A.
Published: May 2006

The results of an investigation of the formal stability behavior of equivalent classes of kinetic equations (generated by stability constraint specifications) that are general enough to include nonpolynomial kinetics are outlined. The immediate motivation for the study arose from the need for a comprehensive theory when steric interactions in biosynthetic networks are explicitly taken into account.
Chloroplast RNA Populations in Dark-Grown, Light-Grown, and Greening
Euglena gracilis
Authors: Brown Ronald D. , Haselkorn Robert
Published: May 2006

RNA preparations from dark-grown, light-grown, and greening
Euglena gracilis
have been compared by polyacrylamide gel electrophoresis and by hybridization to
Euglena
chloroplast DNA. Chloroplast ribosomal RNA is not detected in dark-grown cells; its abundance increases in greening cells over a 72 hr period until the concentration characteristic of light-grown cells is reached. Other RNA species complementary to chloroplast DNA are present in comparable abundance in light-grown, dark-grown, and greening cells.
Characterization of the Inducer Required for the Development of Macrophage and Granulocyte Colonies
Authors: Landau Tamar , Sachs Leo
Published: May 2006

A substance produced by various types of cells can induce from single hematopoietic cells the formation of colonies of normal macrophages and granulocytes. This inducer has been purified 600-fold from serum-free conditioned medium from a tissue culture line of mouse cells. It is shown that the inducer is a protein, with a molecular weight of 65-70,000, whose inducing activity was about 1 ng per colony. Acrylamide gel electrophoresis of this material gave four bands, only one of which contained inducing activity. The purified protein was inactive. Activity was regained by the addition of a low molecular weight cofactor that is present in conditioned medium. Under certain conditions, activity was also regained by the addition of adenosine 3′:5′-cyclic monophosphate (cyclic AMP).
Cell Cycle-Dependent Immune Lysis of Moloney Virus-Transformed Lymphocytes: Presence of Viral Antigen, Accessibility to Antibody, and Complement Activation
Authors: Lerner Richard A. , Oldstone Michael B. A. , Cooper Neil R.
Published: May 2006

The expression of Moloney leukemia virus on the surface of a viral-induced lymphoma cell, availability of the virus to anti-viral antibody, and the nature and extent of activation of the complement system during the cell cycle were studied
in vitro
. Viral antigen was present on the cell surface, accessible to antibody, and was able to activate complement in the presence of antibody throughout all cellular growth phases, while cytotoxicity was confined to the G
1
phase of cell growth. In addition, when cells were arrested in metaphase, viral antigen could be demonstrated on the cell surface by immunofluorescence, and budding virus was seen by electron microscopy. All nine components of complement were activated on the addition of antibody throughout the cell cycle. Additional experiments indicated that in the presence of antibody, C3 and/or C4 were immunospecifically bound to viral-induced lymphoma cells throughout the cell cycle as a result of complement activation. These results indicate that the inability to lyse the cells in the presence of specific anti-viral antibody and complement during the logarithmic phase of cell growth is not due to the lack of expression of Moloney virus antigen(s) on the cell surface, inaccessibility of this surface antigen(s) to antibody, or failure to activate the complement effector system.
Actin in the Brush-Border of Epithelial Cells of the Chicken Intestine
Authors: Tilney Lewis G. , Mooseker Mark
Published: May 2006

The major soluble protein of the isolated brush-border of the intestinal epithelium has a molecular weight and net charge indistinguishable from those of skeletal-muscle actin, as determined by polyacrylamide gel electrophoresis. Furthermore, this protein, isolated from acetone powders of the purified brush-border, undergoes a G to F transformation in the presence of Mg
++
. The filaments have a substructure indistinguishable from muscle actin, as seen by the negative-staining technique, and bind heavy meromyosin with the arrowhead configuration characteristic of actin. The filaments in the microvilli of the intact bruch-border also bind heavy meromyosin. Thus, actin seems to be present in intestinal epithelial cells.
Cochlea of the Dolphin,
Tursiops truncatus:
The Basilar Membrane
Authors: Wever Ernest Glen , Mccormick James G. , Palin Jerry , Ridgway S. H.
Published: May 2006

In the dolphin
Tursiops truncatus
, the basilar membrane over its course its course from basal to apical ends shows a systematic variation in width and in the manner and rigidity of its suspension.

The suspension is by bony laminae on both the outer and inner edges in the basal region, and by progressively less rigid attachments in the more apical regions, until near the apex the membrane is held only by connective tissue.

The basilar membrane shows an unusual variation in width of 14 times, ranging from an astonishingly small value of 25 μm at the basal end to a value toward the apex of about 350 μm. This structural variation is in harmony with the extension of sensitivity of the dolphin ear into the very high frequencies, and suggests unusual capabilities of pitch discrimination in this high range.
Temperature-Dependent Alterations in Sugar Transport in Cells Infected by a Temperature-Sensitive Mutant of Rous Sarcoma Virus
Authors: Martin G. S. , Venuta S. , Weber M. , Rubin H.
Published: May 2006

Cells transformed by Rous sarcoma virus take up 2-deoxyglucose at a faster rate than uninfected cells, under conditions where transformed and nontransformed cells grow at the same rate. In cells infected by a temperature-sensitive mutant, the stimulation of 2-deoxyglucose uptake is temperature dependent: the increase is observed at the permissive (36°C), but not at the nonpermissive (41.5°) temperature. When infected cells are shifted from the nonpermissive temperature to the premissive temperature, the uptake of 2-deoxyglucose increases from a rate equal to that of uninfected cells to a rate equal to that of cells infected by the wild-type Schmidt-Ruppin Rous sarcoma virus. The reverse change occurs when the infected cells are shifted from the permissive to the nonpermissive temperature. By the use of cytosine arabinoside, an inhibitor of DNA synthesis, it was possible to show that DNA synthesis is neither required for the transformation, which occurs when the infected cells are shifted from the nonpermissive to the permissive temperature, nor for the phenotypic reversion, which occurs in the reverse shift.
Role of Erythropoietin in 7,12-Dimethylbenz(a)anthracene Induction of Acute Chromosome Aberration and Leukemia in the Rat
Authors: Sugiyama Taketoshi
Published: May 2006

The incidence of chromosome aberrations in rat bone marrow, examined 6 hr after the administration of 7,12-dimethylbenz(a)anthracene, was significantly enhanced by induction of anemia 0-48 hr before the carcinogen treatment and was suppressed by induction of polycythemia. The suppressive influence of polycythemia was reversed by sheep erythropoietin injected shortly before or after the carcinogen injection; this suppressive effect was proportional to the dose of erythropoietin used. These data suggest that erythropoietin is essential to make bone-marrow cells susceptible to chromosome aberrations with 7,12-dimethylbenz(a)anthracene. The incidence of carcinogen-induced leukemia was also increased by anemia and suppressed by polycythemia induction.
Fractionation of Liver Chromatin
Authors: Marushige Keiji , Bonner James
Published: May 2006

Rat liver chromatin has been fractionated into two fractions on the basis of precipitability in standard saline after mild treatment with DNase II. The major portion of liver chromatin contains little nonhistone protein and is enriched in histones, while a minor portion of such chromatin, with which RNA polymerase is associated, is highly enriched in proteins other than histone and impoverished in histones. Although the relative concentrations of the several histone species present in two chromatin fractions are identical, binding of histones to DNA in the minor fractions appears to be modified, presumably by the presence of proteins other than histones.
Bacterial Mutants in Which the Gene
N
Function of Bacteriophage Lambda Is Blocked Have an Altered RNA Polymerase
Authors: Georgopoulos C. P.
Published: May 2006

Bacterial mutants have been isolated, called
groN
, that block phage development by interference with the action of the product of the phage
N
gene. λ
trp
phages, which depend on the
N
product for the synthesis of tryptophan enzymes, do not make these enzymes in
groN
bacteria. Two type of phage mutants have been isolated that can overcome the
groN
block. One type makes an altered
N
product, the other contains an
N
-bypass mutation.

The
groN
mutation is closely linked to the rifamycin-resistance locus in
Escherichia coli
. Purified RNA polymerase from the
groN
mutant is less activated by salt and more sensitive to rifamycin than is the polymerase from
gro
+
. This suggests that the
groN
mutation produces a structural change in the bacterial RNA polymerase such that it can no longer interact properly with the phage
N
product.
Immunologic Enhancement of Allogeneic Tumor Growth with Soluble Histocompatibility-2 Antigens
Authors: Law Lloyd W. , Appella Ettore , Wright Peter W. , Strober Samuel
Published: May 2006

Soluble, partially purified, histocompatibility antigens that were obtained from the membranes of A/J spleen cells have been assayed for their capacity to elicit immunologic enhancement of two tumors of A-strain origin: YAA-C1 and Sarcoma I. Crude membrane material and a partially purified, soluble antigen that were contained in a specific fraction, obtained after chromatography on a Sephadex G-150 column, elicited enhancement; this fraction has been shown to contain immunogenic histocompatibility-2
a
antigens as well as alloantigenic specificities that were detected serologically. Another soluble fraction did not induce enhancement; this fraction has been shown to contain antigens other than H-2.

Passive enhancement of both tumors was achieved with antisera produced in allogeneic mice that were inoculated with crude membrane material or with a fraction obtained by Sephadex G-150 chromatography. These antisera contained cytotoxic and/or hemagglutinating antibodies. Immunologic enhancement was specific. A readily enhanceable tumor, Py 89, of C57BL origin was not enhanced with anti-H-2
a
antisera.

These results suggest strongly that all important H-2
a
transplantation antigenic determinants of spleen cells can be recovered by partial papain digestion and fractionation on a Sephadex G-150 column.
Reaction of Anti-idiotypic Antibody with the Hapten-Binding Site of a Myeloma Protein
Authors: Brient Bruce W. , Haimovich Joseph , Nisonoff Alfred
Published: May 2006

Rabbit antiserum was prepared against mouse myeloma Protein-315, an IgA protein with specificiy toward the 2,4-dinitrophenyl group. After absorption of the antiserum with another IgA myeloma protein and with affinity-labeled Protein-315, the antiserum was specific for idiotypic determinants on Protein-315. Monovalent ligands that bind to Protein-315 with high affinity strongly inhibited the reaction of the protein with its anti-idiotypic antiserum. This indicated that the region of the hapten-binding site is a major idiotypic determinant. The myeloma protein is thus similar to rabbit antibenzoate antibody in this respect. These results, considered in conjunction with other data in the literature, indicate that an anti-idiotypic antiserum prepared in an isologous or heterologous species can recognize the same determinant, in this case the region comprising the ligand-binding site. Quantitative aspects of the data indicate that there is competition between the hapten and antiidiotypic antibodies for the site.
Germination and Growth of
Neurospora
at Low Water Activities
Authors: Charlang Gisela Wohlrab , Horowitz N. H.
Published: May 2006

When the water activity (

a
w

) of the medium is lowered by the addition of NaCl or nonelectrolytes, an inhibition of germination, growth rate, and total growth is observed in
Neurospora crassa
. Inhibition of conidial germination is separable from the other effects and is caused, in large measure, by the loss from conidia in media of low water activity of a substance that is essential for their germination. The substance is detectable in the medium and is also extractable from cultures. It is dialysable and thermostable, and it appears to be highly active. It is not detectable in complete medium.
On Cell Lethals in
Drosophila
Authors: Stern Curt , Tokunaga Chiyoko
Published: May 2006

Somatic crossing over in flies heterozygous for a dominant Minute mutant may result in two cells, homozygous for wild type and Minute, respectively. If both cells took part in development, a twin spot of two genotypes, different from the rest of the body, would result. Two-hundred wild type spots were found, none of which was accompanied by an adjacent twin spot homozygous for Minute. The absence of these spots shows that their cell lethality is not overcome by transport, including diffusion, across a few cells of gene-dependent material from the neighboring cells which carry one or two wild type alleles of Minute.
DNA-Induced Transformation in
Drosophila:
Genetic Analysis of Transformed Stocks
Authors: Fox Allen S. , Yoon Sei Byung , Gelbart William M.
Published: May 2006

The exosome model of transformation in
Drosophila melanogaster
proposes that DNA fragments enter the cells of treated individuals and become firmly associated with their homologous chromosome segments, but are never integrated into the linear structure of the chromosome. This paper reports results that validate two central predictions of the model: (
a
) the introduced genetic information usually maps precisely at the site of the target locus, and (
b
) the original chromosomal information is still present at that site.
Cytokinin and Growth of Excised Roots of
Bryophyllum calycinum
Authors: Robbins William J. , Hervery Annette
Published: May 2006

Excised roots of
Bryophyllum calycinum
require for growth both auxin and cytokinin. This is demonstrated by the poor growth of 2-mm root tips in a basal medium of mineral salts, sucrose, and vitamins supplemented with either an auxin or a cytokinin, and much better growth when the basal medium is supplemented with both auxin and cytokinin. However, both substances are synthesized by the root, as is demonstrated by the growth of large inocula (dry wt 6-7 mg) through many successive passages in a medium limited to mineral salts, sugar, and vitamins.
The Nature of the Collagen Synthesized by Cultured Human Fibroblasts
Authors: Layman Don L. , McGoodwin Ermona B. , Martin George R.
Published: May 2006

The hydroxyproline-containing proteins (hyproproteins) synthesized by cultured human fibroblasts have been partially characterized. The hyproprotein extracted from the cell layer was found to be similar to the collagen extracted from skin in the ratio of hydroxyproline to proline, chain composition, solubility, and resistance to proteolytic digestion.

The hyproproteins isolated from the medium were different. About 20% of the peptide-bound hydroxyproline was found in randomly coiled chains. The α2 chains were present in considerable excess over the α1 chains, suggesting that the α2 chain may be synthesized in quantities greater than required to form a collagen molecule with a chain composition (α1)
2
α2. The remaining medium hyproprotein appeared to be an unusual form of native collagen which, unlike typical native collagen, was soluble under physiological conditions. This hyproprotein did not yield α chains when denatured and contained material that had a molecular weight greater than α chains. A similar size distribution was observed in the protein synthesized in the presence of β-aminopropionitrile, a specific inhibitor of collagen cross-linking. After treatment with pepsin, typical α1 and α2 chains were obtained from the protein in a 2:1 ratio. Since the medium protein is soluble and has properties different from the typical collagen molecule, it may represent a modified form that functions in the transport of collagen from the cell to the fiber.
The Weierstrass-Laguerre Transform
Authors: Srivastava H. M.
Published: May 2006

An elegant expression is obtained for the product of the inverse Weierstrass-Laguerre transforms of two functions in terms of their convolution. It is also shown how the main result can be extended to hold for the product of the inverse Weierstrass-Laguerre transforms of several functions.
Adenyl Cyclase as a Link between Photon Capture and Changes in Membrane Permeability of Frog Photoreceptors
Authors: Bitensky Mark W. , Gorman Ronnie E. , Miller William H.
Published: May 2006

Tomita has shown by electrophysiological measurements that the photoreceptors of the vertebrate retina are depolarized (excited) by darkness and hyperpolarized (inhibited) by light. Excitation is accompanied by an increase, and inhibition by a decrease, in the sodiumion permeability of the receptor cell.

The retinal-rod outer segments of the frog contain an adenyl cyclase that is active in darkness and inactivated by light. This cyclase has a specific activity ten-times higher than the activity in previously described tissues. It is suggested that cyclic AMP is an intermediate in the light- and dark-induced changes in sodium permeability in the photoreceptor cell.
Isolation of Glucanase-Containing Particles from Budding
Saccharomyces cerevisiae
Authors: Matile P. , Cortat M. , Wiemken A. , Frey-Wyssling A.
Published: May 2006

In an investigation of the role of glucanases in modifying yeast cell walls at the location of new buds, vesicles derived from the endoplasmic reticulum, which are secreted locally into the cell wall of growing buds and may be involved in the secretion of glucanases, have been isolated.

In yeast, exo-β-1,3-glucanase (EC 3.2.1.6) is present both extra- and intracellularly. Exponentially growing cells contain about 16% of the enzyme activity intracellularly (within the plasmalemma). Most, if not all, of this intracellular glucanase is sedimentable. Of the three classes of subcellular particles that contain glucanase, one is almost completely absent from stationary phase cells and almost absent from cells of the late budding phase of the budding cycle. These particles were isolated from budding cells by combined differential and density gradient centrifugation. They contain exo- and endo-β-1,3-glucanases, mannan, and protein. The isolate consists mainly of membrane-bounded particles with diameters corresponding to those of the secretory vesicles observed
in situ
. It is concluded that these particles are identical with the vesicles derived from the endoplasmic reticulum.
Evidence of Widespread Effects of Cloud Seeding at Two Arizona Experiments
Authors: Neyman Jerzy , Osborn Herbert B.
Published: May 2006

The average effect of two cloud seeding experiments (1957-1960; 1961, 1962, and 1964) over the Santa Catalina Mountains, Arizona, on the 24-hr precipitation at Walnut Gulch, 65 miles away, was an apparent 40% loss of rainfall (
P
= 0.025) on seeded, as opposed to not-seeded, experimental days. Larger apparent losses, some highly significant, were found for experimental days on which Walnut Gulch was downwind from the seeding site (but not on upwind days), and also on “second days” of the randomized pairs (but not on “first days”). The timing of significant apparent effects indicated that the afternoon maximum of precipitation, which is very pronounced on days without seeding, is either absent or weakened on days with seeding. This phenomenon was observed earlier in a study of the Whitetop Project.
The Gramicidin A Transmembrane Channel: A Proposed π
(L,D)
Helix
Authors: Urry D. W.
Published: May 2006

A lipophilic, left-handed helical structure is proposed for gramicidin A in which the C-O bonds alternately point toward the amino and carboxyl ends; it is a hybrid of the 4.3
14
and 4.4
16
helices. The C-O groups pointing toward the carboxyl end form part of 16-membered hydrogen-bonded rings, whereas the C-O moieties pointing toward the amino end form 14-membered hydrogenbonded rings. The proposed structure is based on conformational analysis combined with requirements for the gramicidin A transmembrane channel. Two helices combine to form the channel. The alternating C-O directions allow hydrogen-bonded dimerization by the unique possibilities of head-to-head and tail-to-tail attachment. The formyl group at the amino end allows for a favorable head-to-head attachment with no loss of structural continuity. Unpublished studies. by M. C. Goodall on the lipid bilayer conductance of deformyl gramicidin A strongly argue for head-to-head attachment. Such hydrogen-bonded association is not possible with previously described helices, as the C-O groups all point in the same direction. In relation to possible π
(L,D)
helices in mammalian systems, it should be noted that glycines would fill the role of D residues.

The conformation can undergo ion-induced relaxations, which provide approximate tetrahedral coordination for the ion, with facile shifting of coordinations. The ready exchange of coordinations provides the mechanism for movement of the ion along the channel. Conceivably, such transmembrane channels could have application as models for ion transport across biological membranes—an application which may be as great as, or greater than, that of carriers such as valinomycin and nonactin. Specifically, biogenic amines and drugs containing aromatic groups could control access to the channel by interactions with the two tryptophan residues at the ethanolamine end and with the negative region provided by the three oxygens.
Direction of Chain Elongation in the Formation of
Escherichia coli
Ribosomal Protein
Authors: Iwata Sun Ao , Kaji Hideko
Published: May 2006

Ribosomal proteins were isolated from logarithmically growing
Escherichia coli
cells given [
14
C]alanine for short periods. Surprisingly, the specific activity of alanine at the NH
2
-terminal end was higher than that of alanine released by carboxypeptidase A digestion of the ribosomal protein. To determine the direction of chain elongation more precisely,
Escherichia coli
cells were grown with [
3
H]amino acids, and [
14
C]amino acids were then given to the
3
H-labeled cells as a pulse. Radioactive 30S ribosomal proteins were isolated from these cells and subjected to carboxypeptidase digestion. The ratio of
14
C to
3
H of the released amino acids increased as the time for carboxypeptidase digestion progressed. These observations suggest that some of the ribosomal proteins may be synthesized from the carboxyl end to the amino end through a novel mechanism.
Properties of a Soluble DNA Polymerase Isolated from Rous Sarcoma Virus
Authors: Duesberg Peter , Helm Klaus V. D. , Canaani Eli
Published: May 2006

The DNA polymerase of the Prague strain of Rous sarcoma virus of subgroup C and of the Schmidt-Ruppin strain of subgroup A has been solubilized. DNA polymerase purified by sucrose gradient sedimentation and chromatography on DEAE-cellulose represented less than 2% of the soluble [
14
C]protein of the virus. The enzyme was separated from 90% of the viral glycoprotein; it is probably different from the viral group-specific antigen. The sedimentation coefficient (
s

20,
w

) of the soluble DNA polymerase was 8 S before, and 6 S after, incubation with pancreatic RNase. The molecular weight of the 8S DNA polymerase was estimated to be about 170,000, and that of the 6S DNA polymerase to be about 110,000.

Purified DNA polymerase had a high activity with 60-70S viral RNA or salmon DNA as template, but it had a low activity with heat-dissociated 60-70S RNA, influenza virus RNA, or the RNA of tobacco mosaic virus as template. Neither the 8S nor the 6S DNA polymerase had endogenous template activity. The DNA-dependent and the RNA-dependent DNA polymerase activities of the Prague strain coincided in sucrose gradients, both in the 8S and the 6S form. It is concluded that the RNA-dependent and the DNA-dependent DNA polymerase activities of the avian tumor viruses are probably due to the same enzyme.
The Synaptinemal Complex and Four-Strand Crossing Over
Authors: Wettstein D. Von
Published: May 2006

The synaptinemal complex provides a structural basis for four-strand crossing over: prior to chromosome pairing, both sister chromatids of each homologous chromosome participate in the genesis of one lateral component. During precise pairing, the two lateral components are combined into one synaptinemal complex per bivalent.
Structural Measurements in Hemoproteins: Use of Spin-Labeled Protoheme as a Probe of Heme Environment
Authors: Asakura Toshio , Leigh John S. , Drott Henry R. , Yonetani Takashi , Chance Britton
Published: May 2006

With the aid of two kinds of spin-labeled protohemins, the nature of the heme-protein interaction of various hemoproteins was investigated. Di- and mono-spin-labeled protohemins were prepared from protohemin and 2,2,5,5-tetramethyl-3-aminopyrrolidine-1-oxyl. The spin-labeled hemins were recombined with apoproteins of hemoglobin (Hb), myoglobin (Mb), cytochrome
c
peroxidase (EC 1.11.1.5) and horseradish peroxidase (EC 1.11.1.7). Electron paramagnetic resonance spectra of the di- and mono-spin-labeled hemoglobin in 0.1 M potassium phosphate buffer, pH 7.0, at 20°C exhibited moderate immobilization of the labels, while that of cytochrome
c
peroxidase showed stronger immobilization. Di-spin-labeled horseradish peroxidase showed an EPR spectrum of a simple broad line with peak-to-peak line width of 35 G. This broadening is due to spin-spin interaction between the two labels attached at the 6- and 7-positions of the porphyrin ring. Ligand binding to the spin-labeled hemoproteins altered the EPR line shapes and amplitudes. The former is attributed to the changes in the mobility of the labels and the latter to the magnetic dipolar interaction between the heme iron and free radical. From the strength of this interaction the distance between the iron and the nitroxide radical may be calculated. In the hemoproteins examined, the distances are: Hb 12.5 Å, Mb 12.0 Å, cytochrome peroxidase ∼14 Å, and horseradish peroxidase 9.0 Å.
Simian Virus 40 Integration Site in an Adenovirus 7-Simian Virus 40 Hybrid DNA Molecule
Authors: Kelly Thomas J. , Rose James A.
Published: May 2006

The E46
+
strain of Adenovirus 7 is a mixed-virus population containing defective Adenoviurs 7-SV40 hybrid particles and helper, nonhybrid Adenovirus 7 particles. We have applied electron microscopic mapping techniques to obtain a physical map of the genome of the hybrid particles present in E46
+
PL1, a substrain of E46
+
derived from a single two-hit plaque. DNA molecules extracted from purified E46
+
Pl1 virions were found to be linear duplexes, with a mean lenght of 10.9 μm. When these molecules were denatured and renatured, a unique heteroduplex was formed that presumably derived one of its strands from an Adenovirus 7-SV40 hybrid molecule and the other from a nonhybrid Adenovirus 7 molecule. This heteroduplex was double-stranded, except for a short region near one end where the two strands were not paired. On the basis of measurements of the lengths of the single-and double-stranded regions in the heteroduplex, the structure of the Adenovirus 7-SV40 hybrid genome can be reconstructed as follows: The hybrid genome contains 16% less Adenovirus 7 DNA than the nonhybrid Adenovirus 7 genome. This deletion consists of the segment of DNA that maps between 0.05 and 0.21 molecular lenghts in the nonhybrid Adenovirus 7 DNA molecule. The deleted DNA has been partially replaced by an amount of heterologous DNA equivalent to 75% of the complete SV40 genome. A model for the generation of the hybrid genome is presented.
Isolation of an Organ-Specific Leucyl-tRNA Synthetase from Soybean Seedling
Authors: Kanabus Jan , Cherry Joe H.
Published: May 2006

The leucyl-tRNA synthetase activity from cotyledons of 4-day-old soybean seedlings has been fractionated into three components. One of these exclusively acylates two of the six tRNA
Leu
species present in this tissue. The remaining two enzyme fractions charge the other four tRNA
Leu
species equally well. Soybean hypocotyls appear to contain only the last two enzyme fractions.
Light Chains of Myosins from White, Red, and Cardiac Muscles
Authors: Sarkar Satyapriya , Sreter F. A. , Gergely J.
Published: May 2006

Purified preparations of rabbit skeletal white, red, and cardiac muscle myosin (WM, RM, and CM) were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Significant differences in both the molecular weights and number of light chains in these myosins were found. WM has three distinct light-chain components (LC
1W
, LC
2W
, LC
3W
) having molecular weights of 25,500, 17,400, and 15,100, respectively. No component with a molecular weight around 15,000 is present in RM or CM. RM and CM contain components of identical molecular weights close to 25,000 and 17,000 (LC
1CR
and LC
2CR
) which, however, clearly differ in molecular weight from the corresponding subunits in WM. RM has an additional component (LC
1R
) having a slightly higher molecular weight than LC
1W
and LC
1CR
. Thus differences and similarities in many biochemical properties between WM, RM, and CM, which have been described earlier, are also reflected in the light-chain components. The present results support the hypothesis that different sets of genes are active in producing components of myosin that make up different isozymic forms characteristic of each muscle type.
Macromolecular Inhibitor of Fertilization in Rabbit Seminal Plasma
Authors: Davis B. K.
Published: May 2006

A large (86S) glycoprotein isolated from rabbit seminal plasma acts on sperm cells to block fertilization. The proportion of fertilized eggs recovered from does 1 day after tubal insemination of sperm 5-6 hr before or 2-3 hr after ovulation was significantly depressed when uterine-capacitated spermatozoa were exposed to this substance at concentrations of 20-72 μg of protein/ml. Rabbit seminal plasma was estimated to have about 2 mg/ml of this factor. Another large glycoprotein (∼138S) is also present in rabbit seminal plasma; the function of this molecule awaits elucidation.