bluuebunny/crossref_metadata_2025 huggingface dataset:
RIBONUCLEASE V OF ESCHERICHIA COLI, I. DEPENDENCE ON RIBOSOMES AND TRANSLOCATION
Authors: Kuwano Michihiko , Kwan Catherine Ning , Apirion David , Schlessinger David
Published: May 2006

A new RNase activity, tentatively named RNase V, was found in cell-free extracts of
E. coli
. This activity requires ribosomes, G and T factors, tRNA, K
+
or NH
4
+
, Mg
2+
, GTP, and a sulfhydryl compound to degrade poly U, poly A, T4 phage mRNA, or
E. coli
mRNA. RNase V is specific for mRNA; it does not attack ribosomal RNA. It is inhibited by antibiotics that decrease breakdown of mRNA
in vivo
, such as chloramphenicol and streptomycin, and by such agents as 5′-β, γ-methylene-guanosine triphosphate, and fusidic acid, which inhibit ribosome-dependent GTPase and translocation of ribosomes along mRNA. The evidence suggests that RNase V is either an integral part of the ribosome or is tightly associated with it, and that it selectively degrades mRNA in intact cells.
CONTROL OF TYROSINE AMINOTRANSFERASE SYNTHESIS IN TISSUE CULTURE BY A FACTOR IN SERUM
Authors: Gelehrter Thomas D. , Tomkins Gordon M.
Published: May 2006

The hormonal induction of tyrosine aminotransferase in an established line of rat hepatoma cells is enhanced by the presence of a macromolecular component of serum in the inducing medium. The addition of serum to cells previously induced in serum-free medium results in a rapid two- to threefold increase in the rate of tyrosine aminotransferase synthesis, as measured by specific radio-immunoprecipitation techniques, as well as a smaller increase in over-all protein synthesis. The stimulation of protein synthesis by serum is accompanied by an increase in the proportion of ribosomes sedimenting as polysomal aggregates. The increase in the rate of TAT synthesis is largely independent of RNA synthesis as it is insensitive to antinomycin D, suggesting that the serum acts at a site beyond gene transcription. The maximum effect of serum on TAT synthesis requires the continued presence of the hormone inducer.
GENETIC CONTROL OF IMMUNOLOGICAL RESPONSIVENESS IN GUINEA PIGS TO 2,4-DINITROPHENYL CONJUGATES OF POLY-L-ARGININE, PROTAMINE, AND POLY-L-ORNITHINE
Authors: Green Ira , Paul William E. , Benacerraf Baruj
Published: May 2006

The ability of guinea pigs to respond immunologically to dinitrophenyl (DNP)-poly-L-arginine, DNP-protamine, DNP polyornithine, and to unsubstituted poly-L-arginine and protamine is linked to the presence of the poly-L-lysine gene. This gene has previously been demonstrated to control the immune response of guinea pigs to poly-L-lysine, to a copolymer of L-glutamic acid and L-lysine and to haptenic derivatives of these materials.

Although the ability to respond to each of these highly charged compounds is linked to the presence of the poly-L-lysine gene, the cellular immune responses to these antigens is highly individually specific.
INDUCTION OF FERN SPORE GERMINATION
Authors: Weinberg Eric S. , Voeller Bruce R.
Published: May 2006

Light-induced germination of
Anemia
spores can be inhibited by AMO-1618, a selective inhibitor of gibberellin biosynthesis. The inhibitor has no effect on gibberellin-induced dark germination and its inhibition of light-induced germination can be reversed by supplying gibberellin. Barley-endosperm bioassay of concentrates of medium in which spores are imbibed in light reveals the presence of substances with gibberellin-like activity; assay of medium from dark-imbibed spores does not. Simultaneous exposure of spores to sub-optimal levels of light and gibberellin leads to additivity of effect on germination level. Uptake of labeled gibberellin by spores in light is similar to that in darkness. The implications of these findings for the light-dependent synthesis of a gibberellin-like germination substance are discussed. The bearing of the observations upon understanding the interaction of light and gibberellins in seeds of higher plants is considered.
INFECTION OF TOBACCO MESOPHYLL PROTOPLASTS BY TOBACCO MOSAIC VIRUS
Authors: Takebe Itaru , Otsuki Yoshiaki
Published: May 2006

It was proved that the protoplasts prepared from mesophyll of
Nicotiana tabacum
are infected by tobacco mosaic virus. The infection occurred when purified tobacco mosaic virus particles were added to a protoplast suspension in the presence of poly-L-ornithine. The virus multiplied in these protoplasts to a level of 10
6
virus particles per infected protoplast during 24 hours of incubation. The efficiency of infection was remarkably high, exceeding that by mechanical inoculation of tobacco leaves.
MITOTIC ABNORMALITIES IN SEA URCHIN EMBRYOS EXPOSED TO DACTINOMYCIN
Authors: Kiefer Barry I. , Entelis Charles F. , Infante Anthony A.
Published: May 2006

Dactinomycin at concentrations of 10, 20, 25, and 50 μg/ml causes mitotic abnormalities in sea urchin embryos. Sister chromosome separation is impaired and anaphase bridges are frequently formed. The result is an unequal distribution of the chromosome complement to daughter cells. Possible explanations are discussed.
MAREK'S DISEASE HERPES VIRUS: A CYTOMEGALOVIRUS?
Authors: Lee Lucy F. , Roizman Bernard , Spear Patricia G. , Kieff Elliott D. , Burmester B. R. , Nazerian K.
Published: May 2006

The DNA of herpes viruses associated with Marek's disease of fowl contains 56-57 moles of guanine and cytosine per 100. The composition of its DNA and lack of infectiousness of cell-free preparations suggest that the herpes virus associated with Marek's disease belongs to the herpes virus group B which contains predominantly cytomegaloviruses.
STUDIES OF ISOZYME PATTERNS IN NULLISOMIC-TETRASOMIC COMBINATIONS OF HEXAPLOID WHEAT
Authors: Brewer George J. , Sing Charles F. , Sears E. R.
Published: May 2006

Thirty-eight wheat strains, each nullisomic for one chromosome and tetrasomic for a homoeologous (related) one, were analyzed electrophoretically for 12 different enzymes, and a gene (or genes) for alkaline phosphatase was localized to chromosomes 4B and 4D. The other 11 enzymes showed no significant electrophoretic variation. The fact that the only mutants observed affect the same enzyme favors the concept that rigorous selection operates in the polyploids both to preserve certain types of variants and to eliminate others.
NUCLEAR MAGNETIC RESONANCE STUDIES OF THE STRUCTURE AND BINDING SITES OF ENZYMES, X. PREPARATION OF SELECTIVELY DEUTERATED ANALOGS OF STAPHYLOCOCCAL NUCLEASE
Authors: Putter I. , Barreto A. , Markley J. L. , Jardetzky O.
Published: May 2006

Five different selectively deuterated analogs of staphylococcal nuclease (Foggi) were prepared having all but a selected few hydrogen atoms in the enzyme molecule replaced by deuterium. The
1
H-NMR spectra of these analogs are extremely simplified, since they consist of lines arising only from the remaining protonated sites.
Mechanism of Action of 2-Mercapto-1(β-4-pyridethyl)benzimidazole: A Reversible Inhibitor of Interferon Activity
Authors: Friedman Robert M. , Pastan Ira
Published: May 2006

2-mercapto-1(β-4-pyridethyl)benzimidazole (MPB) inhibited the development of antiviral activity induced by interferon in chick cells. The MPB effect was reversed by washing the cells. The action of MPB was on a step immediately following interferon binding but before the cellular RNA and protein synthesis that appear to be required for interferon action. The step blocked by MPB possibly involves cellular phospholipid synthesis.
A Study on the Transcription of the Polyoma Viral Genome
Authors: Hudson J. , Goldstein D. , Weil R.
Published: May 2006

The transcription of polyoma (Py) viral RNA was studied in primary mouse kidney cell cultures (a) during normal, asynchronous infection, (b) under conditions where Py-induced DNA synthesis was inhibited with 5-fluorodeoxyuridine, and (c) after the synchronized onset of Py-induced DNA synthesis. The results obtained suggest that the bulk of Py RNA transcribed after the (asynchronous or synchronized) onset of Py-induced DNA synthesis, designated as „late” Py RNA, corresponds to the polycistronic transcript of most or all of the genetic information contained in a strand of circular Py DNA. The rate at which late Py RNA is transcribed is related to the amount of free Py DNA present in the cultures. Py-infected cultures contain a second, minor component of Py RNA (of one or possibly more species), designated as „early” Py RNA. At least some of this RNA continues to be transcribed if Py-induced DNA synthesis is inhibited with 5-fluorodeoxyuridine and, possibly, also late during normal infection.
Inference from Inadequate and Inaccurate Data, II
Authors: Backus George
Published: May 2006

Having measured
D
numerical properties of a physical object
E
which requires many more than
D
parameters for its complete specification, an observer seeks to estimate
P
other numerical properties of
E
. A previous paper discussed how he can proceed when
E
is adequately described by one member

m
E

of a Hilbert space [unk] of possible models of
E
and when all the observed and sought-for properties of
E
are Fréchet differentiable functionals on [unk]. The present paper describes a technique often available for reducing to this tractable case problems in which the functionals are discontinuous and are defined only on parts of [unk], and [unk] is an arbitrary real linear space. Applications include geophysical inverse problems and numerical differentiation, integration, interpolation, and extrapolation.
Natural-Abundance
13
C Nuclear Magnetic Resonance Spectra of Terpenes and Carotenes
Authors: Jautelat Manfred , Grutzner John B. , Roberts John D.
Published: May 2006

Natural-abundance
13
C nuclear magnetic resonance spectra are reported for some simple terpenes and carotenes. The techniques involved in the assignment of the resonances to specific carbons are outlined. The potential of this nondegradative procedure for structural analysis is demonstrated for the investigation of carbon atoms in chemical and biochemical systems.
The Mating Advantage of Rare Males in
Drosophila
Authors: Ehrman Lee
Published: May 2006

The mating advantage of rare
Drosophila
males in tested using two eye color mutants. In one experiment, the flies remained for three hours in observation chambers containing 25 pairs; in another experiment they stayed for 24 hours in mass cultures of 200 individuals. The outcome of this latter experiment was followed for ten generations, with all competition other than that for mates eliminated. For initial frequencies of 80 per cent for the common and 20 per cent for the rare type, the frequencies converged to approximate equality because the rare males were favored as mates. When the formerly rare type increases in frequency, it loses its mating advantage, and a balanced equilibrium is eventually attained.
Parathyroid Harmone, 3′5′ AMP, Ca
++
, and Renal Gluconeogenesis
Authors: Nagata Naokazu , Rasmussen Howard
Published: May 2006

Isolated segments of renal tubules prepared from rat kidney cortex were capable of sustained rates of gluconeogenesis when lactate served as substrate. An increase in external Ca
++
, or the addition of parathyroid hormone at a fixed Ca
++
concentration led to enhanced rate of gluconeogenesis. However, parathyroid did not increase gluconeogenesis in the absence of external Ca
++
even though it caused a rise in 3′5′ AMP whether Ca
++
was present or absent. Metabolite profiles showed that either an increase in external Ca
++
, or the addition of hormone in the presence of calcium led to qualitatively very similar changes. However, the addition of hormone had little effect upon metabolite levels in the absence of extracellular calcium even though an increase in extracellular H
+
enhanced gluconeogenesis under similar conditions. These results are discussed in relationship to the close association of 3′5′ AMP and Ca
++
in a variety of cellular systems.
Effects of Glucose on Glycogen Synthetase, Phosphorylase, and Glycogen Deposition in the Perfused Rat Liver
Authors: Buschiazzo H. , Exton J. H. , Park C. R.
Published: May 2006

An increase in the perfusate glucose concentration from near zero to about 11 mM increased glycogen synthesis in the perfused, isolated rat liver from zero to a value about half the maximum seen in the intact animal. Increased synthesis appeard to due not only to provision of substrate but also to conversion of glycogen synthetase to the active form and of glycogen phosphorylase to the inactive form. These glucose effects, which are apparently independent of changes in levels of hormones or adenosine 3′:5′-cyclic phosphate, may be physiologically significant for control of the blood glucose level.
Effect of Thyrocalcitonin on Adenosine 3′:5′-Cyclic Phosphate Formation by Rat Kidney and Bone
Authors: Murad Ferid , Brewer H. Bryan , Vaughan Martha
Published: May 2006

Thyrocalcitonin (TCT) increased the rate of accumulation of adenosine 3′:5′-cyclic phosphate (cyclic AMP) when added to incubations containing washed particles from whole rat kidney, adenosine triphosphate (ATP), MgSO
4
, and caffeine. The maximum stimulatory effect of TCT, 44 ± 6.7 per cent, was always less than the 150 to 250 per cent increase produced by parathyroid hormone (PTH). The effect of both hormones together was no greater than that of PTH alone when each was present at a maximally effective concentration. Since neither TCT nor PTH altered the rate of degradation of cyclic AMP by the kidney preparation, it may be inferred that their effects on cyclic AMP accumulation are the result of increased formation of cyclic AMP. Adenyl cyclase activity in homogenates of renal cortex was stimulated to a greater extent by TCT and PTH than was that of medulla, whereas, as reported earlier, the effect of vasopressin was much larger with homogenates of medulla. The accumulation of cyclic AMP in incubations of rat kidney cortex slices was increased 20 to 60 per cent by TCT and 50 to 140 per cent by PTH. The accumulation of cyclic AMP in incubations of rat calvaria was increased about threefold with TCT and nine to tenfold with PTH, while reduced and alkylated TCT had less than 10 per cent of the activity of TCT. These observations are consistent with the view that the physiological effects of TCT and PTH in kidney and bone are secondary to the enhanced formation of cyclic AMP.
Absence of Disulfide Bonds Linking the Heavy and Light Chains: A Property of a Genetic Variant of γA2 Globulins
Authors: Jerry L. M. , Kunkel H. G. , Grey H. M.
Published: May 2006

The γA2 globulins have attracted considerable interest because of the absence of the disulfide bonds linking the heavy and light chains characteristic of all other human immune globulins. Recently a genetic marker (Am
2
) has been found which delineates two genetic variants of γA2 globulins that are controlled by allelic genes. These differ markedly in incidence in different populations with a marked preponderance in Caucasians of the type possessing the Am
2
marker. A study of 22 γA2 myeloma proteins primarily from Caucasians showed that 20 were Am
2
(+), and 2 were Am
2
(-). All of the positive type dissociated in the presence of acid or urea into heavy and light chain dimers without reduction of disulfide bonds, as expected from the earlier studies. However, the two Am
2
(-) proteins failed to dissociate in the presence of acid, urea, guanidine, or detergent. It was only after partial reduction and alkylation that these molecules split into heavy and light chains. Thus the unique absence of disulfide bonds linking the heavy and light chains is a property of only one genetic variant and not of all γA2 proteins.
A Genetic Map of Non-Mendelian Genes in
Chlamydomonas
Authors: Sager Ruth , Ramanis Zenta
Published: May 2006

A group of eight non-Mendelian genes have been shown by recombination analysis to be linked into a linear structure or chromosome. Similar genetic maps of gene order and relative distances between genes have been constructed by two methods, one based on additivity of recombination frequencies, the other on frequency of reciprocal recombination with a postulated attachment point. The data indicate that the progeny are diploid for this linkage group, and that the strands are distributed in a precisely oriented manner at mitosis. Evidence is discussed in support of the view that this linkage group is located in chloroplast DNA.
Nuclear Magnetic Resonance Studies of the Structure and Binding Sites of Enzymes, XII. A Conformational Equilibrium in Staphylococcal Nuclease Involving a Histidine Residue
Authors: Markley J. L. , Williams Myra N. , Jardetzky O.
Published: May 2006

Evidence is presented for the existence of a conformational equilibrium in staphylococcal nuclease, involving one out of the four histidines and none of the other aromatic residues in the polypeptide chain.
Induction of Cytochromes in Human Cells by Oxygen
Authors: Pious Donald A.
Published: May 2006

The mechanism of cytochrome induction in human cells was investigated. Cultured fibroblasts grown in low oxygen had markedly reduced contents of cytochromes A + A
3
, B, and C + C
1
as measured by absorption spectra. Chloramphenicol but not cycloheximide or actinomycin blocked the initial increase in cytochrome oxidase activity in cells shifted from low to ambient oxygen, suggesting that initiation of enzyme induction requires mitochondrial but not cytoplasmic protein synthesis or transcription of nuclear genes. Turnover of cytochrome oxidase was demonstrated in cells in stationary phase.
SV40-Specific RNA in the Nucleus and Polyribosomes of Transformed Cells
Authors: Lindberg Uno , Darnell J. E.
Published: May 2006

Cells transformed by the oncogenic virus SV40 are known to contain viral DNA integrated into cellular DNA and to produce virus-specific RNA. It has been shown that nuclear molecules containing virus-specific sequences are considerably longer than presumed virus-specific mRNA molecules from cytoplasmic polyribosomes. This finding suggests the possibility that cytoplasmic mRNA is derived by the specific cleavage of larger nuclear RNA.
Light Pulse Propagation in Nonlinear Dispersive Medium
Authors: Knight B. W. , Peterson G. A.
Published: May 2006

We investigate the evolution of an optical pulse in a dispersive, nonlinear dielectric material. The technique exploits two adiabatic invariants, action and wave number. The analysis is performed in detail for a nonlinear variant of the Lorentz model. We find that there are two nonlinear generalizations of the linear group velocity. From this we predict that optical shocks can form on either the front or back edge of the wave form.
A Microsurgical Methodology for Human Cells
in Vitro
: Evolution and Applications
Authors: Diacumakos Elaine G. , Holland Scott , Pecora Pauline
Published: May 2006

A methodology for micromanipulating human cells of normal and malignant origin,
in vitro
, has evolved from the study of about 2000 HeLa, ERK (a subline of HeLa cells), and human embryonic lung cells during interphase and mitosis. It is now possible to microinject interphase cells with aqueous and nonaqueous fluids intracytoplasmically. Chromosomes from human embryonic lung metaphase cells have been transplanted. Chromosomes have been manipulated within mitotic human embryonic lung, ERK, and HeLa cells. Clones have been obtained from HeLa cells subjected to such manipulation. Predictable derangements of mitotic cells and their progeny have been obtained. Intranuclear injections of silicone oil, DNA, and sodium chloride solutions have been made with survival of the cells. HeLa cells have been cloned from such injected cells. Subcellular fractions have been introduced into the nuclei and cytoplasms of HeLa and human embryonic lung cells. The lung cells have been subjected to nuclear micropuncture in groups and a clone has been obtained. Virus suspensions have been introduced into the nuclei of HeLa cells without killing the cells. Applications of this methodology are discussed.
Adrenalectomy and the Suppression of Memory by Puromycin
Authors: Flexner Josefa B. , Flexner Louis B.
Published: May 2006

It has previously been shown that expression of memory of maze-learning in mice is blocked by puromycin injected intracerebrally one or more days after the training experience. Bilateral adrenalectomy before training has now been found to protect memory against the effects of puromycin. This protection is absent when adrenalectomy follows training. In view of control experiments, we conclude that adrenalectomy before training modifies factors necessary for the expression of memory and that this alteration makes puromycin ineffective in blocking memory.
Studies of Lp-Lipoprotein as a Quantitative Genetic Trait
Authors: Harvie Nancy R. , Schultz Jane S.
Published: May 2006

Sera from 11 individuals which were classified as Lp(a-) by direct gel diffusion and by absorption tests showed the presence of Lp(a) lipoprotein when the sera were concentrated 120-fold. This Lp(a) antigen was demonstrated by gel diffusion to be indistinguishable from Lp-lipoprotein isolated from known Lp(a+) sera. The Lp(a) preparations from sera classified Lp(a-) also showed electrophoretic mobility in immunoelectrophoresis and schlieren diagrams in ultracentrifugal analyses similar to Lp-lipoprotein from Lp(a+) sera. The proposal is made that observed individual variations in tests for the Lp-lipoprotein reflect a quantitative genetic trait and that it is likely that different individuals produce Lp-lipoprotein in widely varying amounts. The consistency of this proposal with certain previous observations on the Lp system is discussed.
Active Site of α-Chymotrypsin Activation by Association-Desolvation
Authors: Cohen Saul G. , Vaidya Vishnu M. , Schultz Richard M.
Published: May 2006

High reactivity toward α-chymotrypsin is observed for derivatives of β-arylpropionic acids of varied structure—L-α-acylamido compounds, D-cyclized compounds, and, now, L-glycolamide esters. Compensating enthalpy and entropy effects are observed which appear to be caused by changes in water of solvation. High reactivity with varied structure, and physical evidence, appear to rule out induced fit and distortion as important for this enzyme. The high reactivity results from precise fit of the hydrolyzing group at the critical serine-imidazole junction, resulting from binding of the aryl group and restriction of rotation. Part of the energy of binding is used to desolvate the reactant groups of substrate and enzyme, decreasing activation energies by several kilocalories and raising reactivity by 10
3
or more. Solvation by water stabilizes many compounds, allowing them to be present in solution in biological systems. Their reactions may occur as their reactivity is increased when they are desolvated and brought from solution into association with reactive groups in enzymes, membranes, and structured particles.
A Singular Abstract Cauchy Problem
Authors: Donaldson J. A.
Published: May 2006

In this note a singular abstract Cauchy problem is considered. A solution is obtained for this problem in terms of a regular abstract Cauchy problem. As an application we obtain a new solution of the initial value problem for a class of singular partial differential equations.
Genetic Evolution of Bacteriophage, II. Physical Length of the Homologous Region in a Hybrid between Serologically and Morphologically Unrelated Phages
Authors: Akiyoshi Hiroto , Yamamoto Nobuto
Published: May 2006

P22 and P221 DNA were labeled with
3
H-thymidine and hybridized with P22 DNA, P221 DNA, or
Fels 1
DNA immobilized on Millipore membrane filters. With this technique, 31% of the P22 genome was computed to be homologous to the P221 genome. Since the molecular weight of P22 DNA is 2.65 × 10
7
daltons, the homologous region between P22 and P221 should be equivalent to about 8.2 × 10
6
daltons and contain 13,300 nucleotide pairs or about 4400 triplets. Moreover, 46% of the P221 genome was computed to be homologous to the P22 genome. Therefore, the molecular weight of P221 DNA was calculated to be about 1.80 × 10
7
daltons. Sucrose gradient centrifugation showed that the molecular weight of P221 DNA was 2.01 × 10
7
daltons. Thus, the P221 genome is about 25 to 30% smaller than the P22 genome. Further-more, 54% of the P221 genome was found to be homologous to the
Fels 1
genome. However, the labeled P22 DNA hybridized with
Fels 1
DNA was about 2% of the labeled P22 DNA hybridized with P22 DNA.
Rapid Purification and the Immunological Specificity of Mammalian Microtubular Paracrystals Possessing an ATPase Activity
Authors: Nagayama Ariaki , Dales Samuel
Published: May 2006

A new procedure for the rapid purification of vinblastine-induced microtubular paracrystals is described. The paracrystals constitute about 2 per cent of the total protein in L cells. They contain a labile ATPase with a Michaelis constant of 1.0 × 10
-4
. In the immunofluorescence test, sera prepared against paracrystals reacted positively with intracellular paracrystals and the mitotic apparatus. Antisera against paracrystals from a malignant murine cell also labeled the mitotic apparatus of HeLa and chicken embryonic cells, revealing the presence of a common or related antigen in the mitotic apparatus of these higher vertebrates.
Coding and Conformational Properties of Oligonucleotides Modified with the Carcinogen
N
-2-Acetylaminofluorene
Authors: Grunberger Dezider , Nelson James H. , Cantor Charles R. , Weinstein I. Bernard
Published: May 2006

The present studies were undertaken to determine the mechanism by which attachment of the carcinogen
N
-2-acetylaminofluorene to guanosine residues in nucleic acids distors their structure and function. Oligonucleotides were modified with
N
-acetoxy-2-acetylaminofluorene, repurified, and their base compositions analyzed. Evidence is presented that acetylaminofluorene residues bound to guanosines in GpUpU, ApApG, or poly (U,G) inactivates their function in codon recognition. Circular dichroism spectra suggest that this is caused by gross conformational changes in these compounds involving both a rotation about the glycosidic bond of guanosine residues bearing
N
-2-acetylaminofluorene, as well as stacking interactions between the drug and bases adjacent to the substituted guanosine.
13-Desmethyl Rhodopsin and 13-Desmethyl Isorhodopsin: Visual Pigment Analogues
Authors: Nelson Ralph , deRiel J. Kim , Kropf Allen
Published: May 2006

The preparation and properties of three geometric isomers of 13-desmethyl retinal (13-dmr) are described. They are analogous to the all-
trans
, 11-
cis
, and 9-
cis
isomers of retinal since two of the
cis
isomers combine with cattle opsin to form pigments which are spectrally indistinguishable from rhodopsin and isorhodopsin and the all-
trans
isomer is unreactive.

The pigment which resembles rhodopsin, 13-desmethyl (13-dm) rhodopsin, is formed at about one ninth the rate at which 11-
cis
retinal reacts with opsin at 20°C. The reaction with 13-dmr does not go to completion; and 0.05
M
hydroxylamine, to which rhodopsin is stable, decomposes 13-dm rhodopsin. Irradiation of 13-dm rhodopsin results in a
cis
→
trans
isomerization of the chromophore; but the photosensitivity of 13-dm rhodopsin is only 40 per cent that of rhodopsin.

13-dm isorhodopsin, the 13-desmethyl analogue of isorhodopsin, is formed at approximately the same specific rate as 13-dm rhodopsin. The reaction goes to completion and the pigment is not decomposed by 0.03
M
hydroxylamine. 13-dm isorhodopsin can also be photolyzed to the all-
trans
chromophore plus opsin.
Glucocorticoid Regulation of ACTH Sensitivity of Adenyl Cyclase in Rat Fat Cell Membranes
Authors: Braun T. , Hechter O.
Published: May 2006

Plasma membrane sacs of isolated rat fat cells (ghots) possess an adenyl cyclase system, which is activated by lipolytic hormones of disparate molecular structure, including adrenocorticotropin (ACTH), glucagon, and epinephrine. Previous studies indicated that distinctive selectivity units for individual hormones are coupled to the same unit of adenyl cyclase in the fat cell membrane. The present study has shown that ghost cyclase from adrenalectomized and hypophysectomized rats exhibits a striking reduction in response to ACTH, the stimulatory effects of epinephrine, glucagon, or fluoride being unchanged. Pretreatment of adrenalectomized, hypophysectomized, sham operated, or intact rats with the synthetic glucocorticoid, dexamethasone, selectively increased the ACTH response in ghost cyclase preparations. Cortisol, like dexamethasone, increased the ACTH response in ghosts from adrenalectomized rats; 11-deoxycorticosterone was ineffective. The dexamethasone effect to enhance the ACTH response is blocked by actinomycin D or cycloheximide.

The present results show that stimulation of rat fat cell adenyl cyclase by ACTH involves a distinctive molecular entity, which can be clearly differentiated from adenyl cyclase in the membrane as well as from the selectivity sites for epinephrine and glucagon. The data indicate that the biosynthesis of the component required for ACTH stimulation of ghost cyclase—either an ACTH selectivity unit or specific coupling factor—is induced by glucocorticoids at the level of gene regulation.
IMMUNOLOGICAL ALTERNATION OF LEUKEMIC CELLS
In Vivo
AFTER TREATMENT WITH AN ANTITUMOR DRUG
Authors: Bonmassar E. , Bonmassar A. , Vadlamudi S. , Goldin A.
Published: May 2006

L1210 leukemia was transplanted serially in CDF
1
mice treated with 5-(3,3-dimethyl-1-triazeno)imidazole-4-carboxamide (DIC, NSC 45388). After four different lines (C lines) had been treated for several generations, a marked increase in survival time of untreated mice was observed. In contrast, mice treated with DIC or immunosuppressed with cyclophosphamide succumbed earlier with generalized leukemia. Furthermore, a C line showed unusually high sensitivity to chemotherapeutic treatment with 1,3 bis(2-chloroethyl)-1-nitrosourea. The data suggest that C lines acquired strong antigenicity for CDF
1
and DBA/2 hosts. DIC treatment may have selected highly antigenic variants or induced somatic mutations resulting in the appearance of strong new transplantation antigen(s).
SPECIFIC INHIBITION OF TUMOR CELL DNA SYNTHESIS
In Vitro
BY LYMPHOCYTES FROM PERITONEAL EXUDATE OF IMMUNIZED SYNGENEIC GUINEA PIGS
Authors: Oppenheim Joost J. , Zbar Berton , Rapp Herbert
Published: May 2006

Tumor immunity to a transplantable diethylnitrosamine-induced hepatoma in inbred guinea pigs has been found to be immunologically specific and cell mediated. We have investigated this cellular immunity using a quantitative, reproducible, and simple assay based on the ability of leucocytes to inhibit the incorporation of tritiated thymidine (TdR
3
H) by tumor cells. Tumor cell suspensions were obtained from the ascites form or tissue culture monolayers of the hepatoma. Cells from the peritoneal exudate of immunized guinea pigs inhibited tritiated thymidine uptake by tumor target cells to a significantly greater degree than cells from the peritoneal exudate of unimmunized animals. Immune lymph node, peripheral blood, and spleen leucocytes were not inhibitory. The assay was sufficiently sensitive to detect relatively weak tumor immunity. The
in vitro
inhibition was correlated directly with the presence of delayed hypersensitivity and/or inhibition of tumor cell growth in local passive transfer studies. Irradiation of peritoneal exudate cells (3000 R) blocked their inhibitory effects on tumor cells. Fractionation of the peritoneal exudate cells by centrifugation in zones of bovine serum albumin of different density also revealed the lymphocytes to be responsible for the specific inhibitory effects whereas macrophages inhibited in an immunologically nonspecific fashion.
EVIDENCE FOR TRIPLICATE GENES FOR ALCOHOL DEHYDROGENASE IN HEXAPLOID WHEAT
Authors: Hart Gary E.
Published: May 2006

The alcohol dehydrogenase zymogram phenotypes of 40 wheat strains, each possessing a distinctive chromosomal constitution, were determined. Genes involved in the production of alcohol dehydrogenase were located on the beta arm of chromosome 4A and on chromosomes 4B and 4D. The results support the hypothesis that the active alcohol dehydrogenase isozymes are dimers composed of the six possible combinations of subunits coded by triplicate structural genes.
CHANGES IN CHROMOSOMES OF BONE MARROW AFTER INTRAVENOUS INJECTIONS OF 7,12-DIMETHYLBENZ(A)ANTHRACENE AND RELATED COMPOUNDS
Authors: Rees E. Douglas , Majumdar S. K. , Shuck Amy
Published: May 2006

Multiple intravenous injections of an emulsion containing 7,12-dimethylbenz(a)anthracene (DMBA) or 7,8,12-trimethylbenz(a)anthracene (TMBA) induce a high incidence of leukemia in rats. Twenty-four hours after a single injection, about half of the metaphase cells in the marrow have chromosomes with breaks. Although breaks were inflicted on chromosomes of various sizes and morphology, these aberrations were nonrandom in that members of the nos. 1 and 2 chromosome pairs were involved to an extent greater than expected on the basis of their size and number. Distinctive karyotypic abnormalities involving the no. 2 chromosome were observed in half of the leukemic rats, whereas these abnormalities were not observed in nonleukemic, DMBA-treated rats. Benzo(a)pyrene and benzo(e)pyrene, polycyclic aromatic hydrocarbons which did not induce leukemia, produced fewer breaks of the no. 2 (and other) chromosomes than did DMBA or TMBA.
Effects of Heat Treatment of Electron-Transport Particles on Bacterial Oxidative Phosphorylation
Authors: Bogin Eitan , Higashi Taneaki , Brodie Arnold F.
Published: May 2006

The electron-transport particles from
Mycobacterium phlei
exhibit low levels of phosphorylation unless supplemented with soluble coupling proteins. Heat treatment of the electron transport particles for 15 min at 50°C was found to result in a slight loss of oxidation and an activation of phosphorylation with NADH as substrate, while with succinate as substrate both activities increased. The heat-activated particles do not require the addition of soluble coupling factors and their level of oxidative phosphorylation is similar to that of the regular particles supplemented with the soluble coupling factors. In contrast to the lack of a requirement for the
soluble
coupling factors after heat activation, the heat-treated electron-transport particles require the presence of a particulate-bound coupling factor for phosphorylation. The heat-activated system, like the untreated system, was found to be sensitive to uncoupling agents.
Deficient Photosystem II in Agranal Bundle Sheath Chloroplasts of C
4
Plants
Authors: Woo K. C. , Anderson Jan M. , Boardman N. K. , Downton W. J. S. , Osmond C. B. , Thorne S. W.
Published: May 2006

A method is described for separating mesophyll and bundle sheath chloroplasts from the leaves of C
4
plants. The agranal bundle sheath chloroplasts are inactive in the Hill reaction, whereas granal bundle sheath and granal mesophyll chloroplasts exhibit normal photosystem II activity. The agranal bundle sheath chloroplasts are deficient in photosystem II; they lack cytochrome
b
-559 and the fluorescence bands associated with photosystem II. All the chloroplasts exhibit photosystem I activity.
Role of Adrenal Cortical Function in Toxicity of Polyriboinosinic·Polyribocytidylic Acid and Its Component Homopolymers
Authors: Zedeck Morris S. , Marquardt Hans , Sternberg Stephen S. , Fleisher Martin , Hamilton L. D.
Published: May 2006

Adrenalectomized rats are 1000 times more sensitive to lethal effects of the double-stranded complex polyriboinosinic·polyribocytidylic acid than intact rats. They are protected from such lethal effects by corticosterone. The complex can rapidly induce diffuse, severe necrosis of villous epithelium in small intestine without damage in crypts. Injection of the individual homopolymers, polyriboinosinic acid and polyribocytidylic acid, separately but in rapid succession is at least as lethal as injection of the complex.
Antigenic Study of Unfertilized Mouse Eggs: Cross Reactivity with SV40-Induced Antigens
Authors: Baranska Wanda , Koldovsky Pavel , Koprowski Hilary
Published: May 2006

Serum obtained from guinea pigs immunized with unfertilized C57BL/6 mouse eggs was found to be cytotoxic in the presence of complement for eggs obtained from syngeneic and allogeneic mice. The anti-egg serum was not cytotoxic for rat eggs, lymph node cells, methylcholanthrene-induced tumor cells, or 3T3 cells obtained either from syngeneic or allogeneic mice. The anti-egg serum was, however, cytotoxic for SV40-transformed 3T3 cells and C57BL/6 cells. After absorption with SV40-transformed cells, anti-egg serum lost its cytotoxicity for mouse eggs.
Immunofluorescent Detection of Herpesvirus Antigens in Exfoliated Cells from Human Cervical Carcinoma
Authors: Royston Ivor , Aurelian Laure
Published: May 2006

Exfoliated cells from patients with squamous carcinoma of the cervix contain antigens related to herpesvirus subtype 2, as revealed by direct or indirect immunofluorescent techniques. Normal squamous cells from the same subjects and from controls without the disease, and cells from a small number of tumors at sites other than the cervix, did not react with anti-herpesvirus subtype 2 serum. Antisera to adenovirus 18 or mycoplasma orale did not react with the exfoliated cells.
5-Bromodeoxyuridine-Induced Differentiation of a Neuroblastoma
Authors: Schubert David , Jacob François
Published: May 2006

5-Bromodeoxyuridine induces the differentiation of mouse neuroblastoma C1300 to cells that morphologically resemble mature neurons. The induced differentiation can take place in the absence of DNA synthesis. This suggests that the halogenated pyrimidine need not be incorporated into DNA to alter the phenotype of the cell.
A Model for Gallbladder Function and Cholesterol Gallstone Formation
Authors: Cussler E. L. , Evans D. Fennell , DePalma Ralph G.
Published: May 2006

An analysis of fluid mechanics and diffusion in the gallbladder predicts that there is a thin layer of high bile-constituent concentration near the gallbladder wall. Cholesterol may precipitate in this layer, even when the average cholesterol concentration in the gallbladder is below saturation. The amount precipitated increases with time, with increased average cholesterol concentration, and with decreased average lecithin concentration. If the gallbladder does not empty completely, the precipitated cholesterol particles may grow over many cycles of gall bladder filling and emptying. The analysis explains why cholesterol-gallstone formation is not correlated with bile-constituent concentration alone, why a flaccid, noncontractile, gallbladder has a greater chance of forming gallstones, why small stones are frequently found near the gallbladder wall, and why stones may be found in only one limb of a double gallbladder.
Possible Role of Pyrophosphate Linkage in the Active Transport of Sodium Ions
Authors: Wang Jui H.
Published: May 2006

Based upon the observation that the pyrophosphate group has a greater affinity for sodium ion than for potassium ion, and that both of these ions catalyze transphosphorylation, a simple molecular mechanism is formulated for the active transport of sodium ions across biological membranes. It is assumed that the active transport takes place along a chain of phosphomonoester groups in the membrane. Pyrophosphate linkages are synthesized at the inner boundary of the membrane by a sodium-activated kinase and hydrolyzed at the outer boundary of the membrane by a potassium-activated pyrophosphatase. It is shown that in such a model the pyrophosphate linkages can diffuse across the membrane and carry sodium ions in the direction of increasing sodium ion concentration.
Polyoma „Tumor Antigen”: An Activator of Chromosome Replication?
Authors: Weil Roger , Kára Jindřich
Published: May 2006

We have studied the temporal relationship between the appearance of polyoma-specific „tumor antigen” and polyoma-induced activation of the cellular DNA-synthesizing apparatus in „contact-inhibited” mouse-kidney tissue-culture cells. The experimental results are compatible with the hypothesis that virus-induced replication of the mouse cell chromosomes, which accompanies the actual production of progeny virus, is triggered by the tumor antigen. On the basis of the experimental evidence at present available we propose a tentative scheme of the lytic cycle of polyoma virus, that is of the events which lead to and accompany the production of polyoma progeny virus.
DNA Synthesis by RNA-Containing Tumor Viruses
Authors: Scolnick Edward M. , Aaronson Stuart A. , Todaro George J.
Published: May 2006

Murine leukemia (Rauscher and Moloney strains) and sarcoma (Kirsten strain) virions, as well as the mammary tumor virus of mice, contain an RNA-dependent DNA polymerase. Optimal incorporation of deoxyribonucleoside triphosphates occurs at a critical detergent (Triton X-100) concentration (0.010-0.014%). At higher than optimal detergent concentrations the virion is seen to be disrupted and enzyme activity is lost. The virion, enzymatic activity, and newly synthesized DNA all cosediment in a sucrose gradient. Thus far the enzymatic activity has been found only in RNA viruses that have oncogenic properties.
Correlation of
In Vivo
and
In Vitro
Phase Transitions of Membrane Lipids in
Escherichia coli
Authors: Overath P. , Schairer H. U. , Stoffel W.
Published: May 2006

A double mutant of
Escherichia coli
unable to synthesize or degrade unsaturated fatty acids can incorporate fatty acids with various hydrocarbon chain structures into the membrane phospholipids. The temperature characteristic of three physiological properties of cells grown with different fatty acids (growth, respiration, and efflux of thiomethylgalactoside) is compared with the physical properties of the isolated phosphatidylethanolamines in monolayers at an air-water interface. Breaks in the temperature characteristic of the properties measured
in vivo
correspond to phase transitions in the lipid films from a liquid-expanded to a condensed form. It is concluded that a liquid-like state of the lipid phase is required for proper membrane function.
Isolation of RNA with Properties of Messenger RNA from Cerebral Polyribosomes
Authors: Zomzely Claire E. , Roberts Sidney , Peache Susan
Published: May 2006

RNA which dissociated from purified cerebral polyribosomes of adult rats in the presence of EDTA was isolated by fractionation in a discontinuous sucrose gradient. The yield was 2% of the total polyribosomal RNA. The base composition resembled the complementary values for rat DNA and was very different from base compositions of ribosomal RNA and transfer RNA. This RNA fraction contained a large proportion of molecules which were rapidly labeled
in vivo
and hybridized to homologous DNA. The polyribosomal RNA preparation also exhibited high template activity in a cerebral cell-free system which had previously been stripped of the capacity to incorporate amino acids in the absence of added messenger RNA (mRNA). Sedimentation analysis revealed only two peaks, with coefficients of approximately 8 S and 16 S. The data indicate that RNA with the properties of mRNA can be selectively isolated from cerebral polyribosomes under mild conditions which avoid degradation.
The Relationship of African Apes, Man, and Old World Monkeys
Authors: Leakey L. S. B.
Published: May 2006

The conclusions of Wilson and Sarich (
Proc. Nat. Acad. Sci. USA
, 63, 1088-1093 (1969) that the human lineage diverged from that leading to the African apes about 4 to 5 million years ago is shown to be based upon a wholly unsupported assumption that the Superfamilies Hominoidea and Cercopithecoidea only separated from each other some 30 million years ago. This is entirely contrary to most recent palaeontological evidence.
Serological and Immunogenic Activity of Soluble Mouse Transplantation Antigens Controlled by the
H
-2 Locus
Authors: Strober Samuel , Appella Ettore , Law Lloyd W.
Published: May 2006

The solubilization and partial purification of mouse transplantation antigens were monitored by (1) an
in vitro
assay for alloantigenic specificities and (2) an
in vivo
assay for transplantation antigens controlled by the
H
-2 histocompatibility locus. Antigens from A/J mice were solubilized by papain and fractionated on a Sephadex G-150 column. The eluate showed a 280 nm absorbance peak (F
1
) in the excluded volume and two peaks (F
2
and F
3
) in the included volume. H-2 specificities 1, 3, 4, 5, 11, 23, and 28 were confined to a single peak in the F
2
fraction.

Fractions F
1
, F
2
, and F
3
, were tested for their ability to accelerate skin graft rejection in noncoisogenic strains which differ at both
H
-2 and
non-H
-2 loci, and coisogenic strains which differ only at the
H
-2 locus. All fractions produced significant acceleration of graft rejection in the noncoisogenic strains, but only fraction F
2
produced significant acceleration in the coisogenic strains. These findings indicate that H-2 transplantation antigens detected by our
in vivo
assay, and H-2 alloantigenic specificities detected by our
in vitro
assay are solubilized by papain and are eluted in the same peak during Sephadex fractionation.
Isolation of a Second Avian Leukosis Group-Specific Antigen (gs-b) from Avian Myeloblastosis Virus
Authors: Allen David W. , Sarma Padman S. , Niall Hugh D. , Sauer Robert
Published: May 2006

Gs-b, a second group-specific antigenic protein of the avian leukosis group, has been isolated from Tween 80-ether treated avian myeloblastosis virus by Sephadex and carboxymethylcellulose chromatography, and compared by immunological and chemical means with the antigen (gs-a) described previously.
Mechanism of Polymerization of the
Salmonella
O-Antigen: Utilization of Lipid-Linked Intermediates
Authors: Kanegasaki Shiro , Wright Andrew
Published: May 2006

Cell envelope fractions from
Salmonella
can utilize exogenous lipid-linked intermediates for the synthesis of polymeric O-antigen. We describe a method for preparing aqueous suspensions of lipid intermediates and show that freezing and thawing of cell envelope-lipid intermediate mixtures is required for efficient synthesis. The lipid intermediates move freely in the hydrophobic environment of the membrane.
Differentiation of Mouse Plasmocytomas
In Vitro:
Two Phenotypically Stabilized Variants of the Same Cell
Authors: Paraf A. , Moyne M. A. , Duplan J. F. , Scherrer R. , Stanislawski M. , Bettane M. , Lelievre L. , Rouze P. , Dubert J. M.
Published: May 2006

Mouse myelomas from Balb/c and C3H mice were established in tissue culture for more than 200 passages. When allowed to attach to a surface, they differentiated into two stabilized forms, one of which was fibroblast-shaped, grew without contact inhibition, and could be transplanted back to mice. The other had the morphology of epithelial cells, showed contact inhibition, and was not transplantable back to mice. For one strain (MOPC 173) it was demonstrated that both types of cells synthesize molecules with idiotypic determinants of the original myeloma protein. The relationship between the host cells and a leukemia-type virus present in the original tumor cells has been studied during different stages of cellular differentiation.
Temperature-Sensitive Mutations in
Drosophila melanogaster
, V. A Mutation Affecting Concentrations of Pteridines
Authors: Grigliatti Thomas , Suzuki David T.
Published: May 2006

A temperature-sensitive
ras
allele has an effective lethal phase at 29°C about 12 hr after pupation and a temperature-sensitive period for lethality beginning midway through the third larval instar and ending around pupation. The mutation also alters the quantity of pteridines present in the eyes, testes, and Malpighian tubules at 29°C. The temperature-sensitive period for pigment production in the Malpighian tubules occurs in the egg and first instar larvae, and in eyes and testes after pupation. The demonstrated autonomy of the mutant in the eyes implies the tissue-specific functioning of the gene. We suggest that the different temperature-sensitive periods for a single mutation indicate tissue-specific activation of a gene at different times during development, although the possibility of activation of preformed polypeptides has not been eliminated.