bluuebunny/crossref_metadata_2025 huggingface dataset:
TRANSFER RNA METHYLASES DURING MORPHOGENESIS IN THE CELLULAR SLIME MOLD
Authors: Pillinger David , Borek Ernest
Published: May 2006

The enzymes that methylate tRNA were studied during the life cycle of the colonizing slime mold,
Dictyostelium discoideum
. Total and base specific tRNA methylase activities were determined in extracts from cells in morphogenetic synchrony. Eight hours after enforced aggregation, the total methylase capacity is reduced by about 40 per cent. The diminution appears to be due to the presence of inhibitors that do not inhibit the base specific enzymes to the same extent. There is a still greater diminution in enzyme activity in extracts of the mature fruiting bodies.
DNA-DEPENDENT RNA-DIRECTED PROTEIN SYNTHESIS
in vitro
, II. SYNTHESIS OF A ϕX-174 COAT PROTEIN COMPONENT
Authors: Gelfand David H. , Hayashi Masaki
Published: May 2006

We present evidence to show that the primary protein product of an
in vitro
DNA-dependent RNA-directed protein-synthesizing system primed by ϕ
X
-174 replicative form DNA comigrates in a gel electrophoresis system with a phage structural component. This protein component is precipitable by antiserum to purified phage.
THE EFFECT OF REDOX POTENTIAL ON P870 FLUORESCENCE IN REACTION CENTERS FROM
Rhodopseudomonas spheroides
Authors: Reed Dan W. , Zankel Kenneth L. , Clayton Roderick K.
Published: May 2006

We have prepared photosynthetic reaction centers from
Rhodopseudomonas spheroides
and have studied the fluorescence of the photochemical electron donor, P870. The yield of this fluorescence rises at low redox potential, presumably because the photochemical electron acceptor becomes reduced and the photochemical utilization of excitation energy is then prevented. The redox titration curve for this increase in the fluorescence has a shape corresponding to the transfer of one electron. The midpoint potential is -0.05 volt, independent of the pH from 6.5 to 8.8. The amplitude of a light-induced absorbance change at 280 nanometers varies with redox potential and shows, at pH 7.5, a midpoint potential of 0.00 volt. These studies indicate that the primary photochemical electron acceptor is not ubiquinone and is not the substance responsible for the absorbance change at 280 nanometers.
THE COVALENT STRUCTURE OF AN ENTIRE γG IMMUNOGLOBULIN MOLECULE
Authors: Edelman Gerald M. , Cunningham Bruce A. , Gall W. Einar , Gottlieb Paul D. , Rutishauser Urs , Waxdal Myron J.
Published: May 2006

The complete amino acid sequence of a human γG1 immunoglobulin (Eu) has been determined and the arrangement of all of the disulfide bonds has been established. Comparison of the sequence with that of another myeloma protein (He) suggests that the variable regions of heavy and light chains are homologous and similar in length. The constant portion of the heavy chain contains three homology regions each of which is similar in size and homologous to the constant region of the light chain. Each variable region and each constant homology region contains one intrachain disulfide bond. The half-cystines participating in the interchain bonds are all clustered within a stretch of ten residues at the middle of the heavy chains.

These data support the hypothesis that immunoglobulins evolved by gene duplication after early divergence of V genes, which specified antigen-binding functions, and C genes, which specified other functions of antibody molecules. Each polypeptide chain may therefore be specified by two genes, V and C, which are fused to form a single gene (translocation hypothesis). The internal homologies and symmetry of the molecule suggest that homology regions may have similar three-dimensional structures each consisting of a compact domain which contributes to at least one active site (domain hypothesis). Both hypotheses are in accord with the linear regional differential of function in antibody molecules.
HIGH EFFICIENCY, HETEROSIS, AND HOMEOSTASIS IN MITOCHONDRIA OF WHEAT
Authors: Sarkissian Igor V. , Srivastava Hari K.
Published: May 2006

Mitochondria of a wheat hybrid 31MS × 28 when assayed polarographically exceeded mitochondria of parents of the hybrid in ADP:O ratios and in respiratory control when they utilized alpha-ketoglutarate, malate, and succinate. The ADP:O ratios of the hybrid mitochondria for the three substrates were 5.8 ± 0.2, 3.8 ± 0.15, and 3.4 ± 0.2, respectively. High P:O ratios were also observed in manometric assays. Mixtures of parental mitochondria exceeded averages of the parents, i.e., they exhibited complementation and approached activities of hybrid mitochondria. Complementation was observed only with NAD-linked substrates. Dinitrophenol uncoupled all mitochondria, but uncoupling was smallest in hybrid mitochondria. Hybrid mitochondria had the greatest ATPase activity. Mixtures exhibited complementation in ATPase activity. ATPase activity was stimulated least in hybrid mitochondria and in parental mixtures. The results were discussed from the point of view that the high P:) ratios gave us direct evidence that heterosis is indeed characterized by high efficiency. It is also pointed out that because of consistent repeatability and their specificity to hybrids, P:O ratios studied in rapidly isolated mitochondria of hybrids may give us revealing information on supramaximal efficiency of oxidative phosphorylation.
A NEW PRINCIPLE FOR ELECTROMAGNETIC CATHETER FLOW METERS
Authors: Kolin Alexander
Published: May 2006

An electromagnetic catheter flow meter is described in which the magnetic field is generated by two parallel bundles of wire carrying equal currents in opposite directions. The electrodes are fixed centrally to the insulated wire bundles that generate the magnetic field. The flow sensor is flexible, resembling a split catheter. The flow transducer is designed to constrict as it is introduced through a branch artery and to expand in the main artery over the span of its diameter. The principle is suitable for branch flow measurement as well as for measurement of flow in a major artery or vein by the same transducer. A special method of guiding the electrode wires results in a zero base line at zero flow for the entire range of diameters accommodating the field generating coil. The electrodes could be used in this configuration with a magnetic field generated by coils external to the patient for blood flow measurements with a catheter of reduced gauge. The transducer can be made smaller in circumference than those employed in other electromagnetic flow measuring catheter devices. This feature is of special value for envisaged clinical uses (percutaneous introduction) to minimize surgical intervention.

The velocity sensitivity of the flow transducer is a logarithmic function of the tube diameter. The flow throughout the entire tube cross section contributes to the flow signal. It is sufficient to calibrate the transducer by one measurement in a dielectric conduit of less than maximum diameter. The sensitivity at other diameters follows from a logarithmic plot. The diameter of the blood vessel is outlined by the transducer in radiograms, thus obviating the need for radiopaque materials. The principle was demonstrated by measurements
in vitro
. Experiments
in vivo
, derivation of equations, and construction details will be published elsewhere.
“TRANSCRIPTIONAL MAPPING,” I. INTRODUCTION TO THE METHOD AND THE USE OF ACTINOMYCIN D AS A TRANSCRIPTIONAL MAPPING AGENT
Authors: Bleyman Michael , Woese Carl
Published: May 2006

The transcription process can in theory be used for genetic mapping on the “intraoperonal” level. We have shown that such an approach, utilizing actinomycin D to create blocks to the travel of the transcription enzyme, is indeed feasible, and the effects of actinomycin D on the synthesis of general pulse-labeled RNA are reported herein.
MIXED CULTURE CYTOPATHOGENICITY: A NEW TEST FOR GROWTH OF MURINE LEUKEMIA VIRUSES IN TISSUE CULTURE
Authors: Klement Vaclav , Rowe Wallace P. , Hartley Janet W. , Pugh Wendell E.
Published: May 2006

Tissue culture cells of a Rous virus-induced rat tumor undergo syncytium formation when placed in contact with mouse embryo cell cultures infected with murine leukemia viruses. This phenomenon can be used as a cytopathic end point for isolating and titrating these viruses in tissue culture. The principle should be applicable to detection of leukemia viruses of other species.
CYTOKININS: DISTRIBUTION IN TRANSFER RNA SPECIES OF
Escherichia coli
Authors: Armstrong D. J. , Burrows W. J. , Skoog F. , Roy K. L. , Söll D.
Published: May 2006

This distribution of cytokinin activity in tRNA species of
Escherichia coli
has been determined. Cytokinin activity was restricted to tRNA species recognizing codons with the initial letter U. The following have been shown to contain a cytokinin: tRNA
Phe
, tRNA
Leu
UUG, tRNA
Ser
UC
G
A
, tRNA
Tyr
, and tRNA
Try
. tRNA
Cys
was present in fractions with cytokinin activity but was not sufficiently pure to prove it to be active. One tRNA
Ser
UC
C
U
species was inactive.

All major tRNA species recognizing condons with initial letters other than U were devoid of cytokinin activity in the tobacco bioassay.

The significance of these findings is discussed as providing a possible mechanism of quantitative modulation at the translation stage of gene-controlled protein biosynthesis.
A LIPID REQUIREMENT FOR INDUCTION OF LACTOSE TRANSPORT IN
Escherichia coli
Authors: Fox C. Fred
Published: May 2006

The rate of derepressed synthesis of a membrane protein required for lactose transport (M protein) by
Escherichia coli
is increased in response to increased gene dosage to the same extent as the rates of synthesis of β-galactosidase and galactoside acetylase. However, elevated gene dosage does not increase β-galactoside
transport
to the same extent that it increases synthesis of M protein and of the soluble proteins of the
lac
operon. Though the factor or factors other than M protein which limit induction of the transport system at high levels of
lac
operon expression have not been identified, studies with
Escherichia coli
mutants blocked in the synthesis of unsaturated fatty acids indicate that unsaturated fatty acids must be supplied during the course of induction of the
lac
operon to permit synthesis of a functional lactose transport system, but not of β-galactosidase or galactoside acetylase.
STIMULATION OF ANTERIOR PITUITARY ADENYL CYCLASE ACTIVITY AND ADENOSINE 3′:5′-CYCLIC PHOSPHATE BY HYPOTHALAMIC EXTRACT AND PROSTAGLANDIN E
1
Authors: Zor Uriel , Kaneko Toshio , Schneider Herman P. G. , McCann Samuel M. , Lowe Irene P. , Bloom Gail , Borland Barbara , Field James B.
Published: May 2006

Hypothalamic extract, containing the releasing factors for anterior pituitary hormones, within minutes stimulated adenyl cyclase activity and adenosine 3′:5′-cyclic phosphate (cyAMP) concentrations in rat anterior pituitary
in vitro
. Cerebral cortical extract was ineffective and hypothalamic extract had no effect on these parameters in posterior pituitary or thyroid. Prostaglandin E
1
also increased adenyl cyclase activity and cyAMP levels in anterior pituitary tissue. Although NaF augmented adenyl cyclase activity, it did not elevate cyAMP. Epinephrine, norepinephrine, histamine, serotonin, dopamine, and vasopressin did not increase either adenyl cyclase or cyAMP. The increased adenyl cyclase and cyAMP produced by hypothalamic extract was associated with greater luteinizing hormone release from anterior pituitary
in vitro
.
HOMOLOGY OF
Pseudomonas
CYTOCHROME
c
-551 WITH EUKARYOTIC
c
-CYTOCHROMES
Authors: Needleman Saul B. , Blair Terence T.
Published: May 2006

The homology of
Pseudomonas
cytochrome
c
-551 with eukaryotic cytochromes
c
is examined with a computer-based procedure devised to determine whether similarities exist between these proteins. One method is given by which the more recently evolved cytochromes
c
might have arisen from the
Pseudomonas
protein. This procedure involves only common genetic phenomena and accounts for most of the structural differences between the bacterial and mammalian cytochromes. A time-scale relationship between the
c
-cytochromes from several microorganisms, a mold, yeast, and the eukaryotic organisms is proposed.
SOLUBILIZATION AND PARTIAL CHARACTERIZATION OF A PHYTOHEMAGGLUTININ RECEPTOR SITE FROM HUMAN ERYTHROCYTES
Authors: Kornfeld Stuart , Kornfeld Rosalind
Published: May 2006

Trypsin treatment of human erythrocytes releases a soluble glycopeptide which binds to phytohemagglutinin and abolishes the erythroagglutinating and lymphocyte-stimulating properties of this molecule. The glycopeptide has been purified by alkaline borohydride treatment, proteolytic digestion, gel filtration, and DEAE-cellulose chromatography. The most highly purified glycopeptide has a molecular weight of about 2,000. The specificity for binding to phytohemagglutinin resides in the oligosaccharide portion of the molecule with the determinant sugar being a galactose residue which is penultimate to a
N
-acetylneuraminic acid in some chains and uncovered in others. The glycopeptide is about 3,000 times more potent than either
N
-acetylgalactosamine or galactose in inhibiting the mitogenic response of lymphocytes induced by phytohemagglutinin.
ELECTRON SPIN RESONANCE OF IRRADIATED SINGLE CRYSTALS OF L-PHENYLALANINE-HCL
Authors: Fasanella Edwin L. , Gordy Walter
Published: May 2006

Single crystals of L-phenylalanine-HCl have been observed with electron spin resonance after irradiation with a cobalt 60 γ-ray source. The predominant signals observed are from long-lived benzyl radicals. The results indicate that one form of radiation damage to proteins containing this amino acid is breakage of the carbon-carbon bond to release the benzyl radical from the polypeptide chain. Hyperfine structure due to proton couplings of the two methylene hydrogens and of the hydrogens on the ring of the benzyl radical is observed and analyzed to give the electron spin density on the various carbons. The spin density on the methylene carbon is found to be 0.71; that on carbon C
(2)
, C
(4)
, or C
(6)
is 0.17. The sum of the spin densities on C
(1)
, C
(3)
, and C
(5)
is —0.22.
A CLONAL ANALYSIS OF DETERMINATION IN
Antennapedia
, A HOMOEOTIC MUTANT OF
Drosophila melanogaster
Authors: Postlethwait John H. , Schneiderman Howard A.
Published: May 2006

The process by which cells select one of several specific programs of genetic information in development was examined in homoeotic mutant
Antennapedia of Rappaport
in
Drosophila melanogaster
. The results show that the alteration of determination from antenna to leg induced by this homoeotic mutation occurs in a population of cells related by proximity rather than by pedigree. Clones of cells marked by means of X-ray-induced somatic crossing-over prior to early third instar participated in the formation of both antenna and homoeotic leg, but after this time, the clone was restricted to either antenna or homoeotic leg, indicating that determination occurs in the third larval instar. The results are discussed in relation to other processes of determination.
AGING OF α-CRYSTALLINS DURING DEVELOPMENT OF THE LENS
Authors: Palmer Winifred G. , Papaconstantinou John
Published: May 2006

Fetal α-crystallin from the bovine lens can be resolved into three major subunit fractions by ion exchange chromatography. A fourth subunit gradually arises during the development of the lens. Incorporation studies indicate that this subunit is not formed by
de novo
synthesis but by the chemical conversion of one subunit into another. Possible mechanisms for this conversion are discussed.
MINIMIZATION OF POLYPEPTIDE ENERGY, VIII. APPLICATION OF THE DEFLATION TECHNIQUE TO A DIPEPTIDE
Authors: Crippen Gordon M. , Scheraga Harold A.
Published: May 2006

In minimizing the energy of a polypeptide, it is necessary to be able to move out of local minima in the search for the global minimum of the energy. For this purpose, the standard technique of deflation (in solving systems of nonlinear equations) is described and applied to the calculation of various stationary points on the energy surface of the “dipeptide” glycyl-L-alanine. The results compare favorably with a detailed contour map of the energy surface. Of special interest is a deep minimum near (ϕ,Ψ) ∼ (240°, 120°) which was found by the deflation technique but which had usually been overlooked in previous investigations.
NUCLEAR AND MITOCHONDRIAL DNA FROM WILD-TYPE AND PETITE YEAST: CIRCULARITY, LENGTH, AND BUOYANT DENSITY
Authors: Billheimer Foster E. , Avers Charlotte J.
Published: May 2006

Purified mitochondrial and nuclear DNA from diploid isogenic wild-type and vegetative-petite baker's yeast were analyzed by electron microscopy and by analytical ultracentrifugation in CsCl gradients. The buoyant densities in CsCl of nuclear DNA were identical for the two strains (ρ = 1.700), but there was a difference between mitochondrial DNA from the wild type (ρ = 1.684) and the petite (ρ = 1.680). Electron microscopy revealed both circular and linear filaments for nuclear and for mitochondrial DNA of both strains. Nuclear DNA molecules included 6.5 per cent cyclic filaments principally measuring 2 μ or less in contour length, and linear filaments showing a unimodal, disperse length-distribution centered at about 2 to 3 μ, for both strains. Mitochondrial DNA for wild type varied depending upon the method used to extract and purify the molecules; showing only 7.5 per cent circular molecules from CsCl-subfractionated samples, as compared with 15 per cent circles from chloroform-extracted DNA not subjected to CsCl and up to 50 per cent circles from osmotically-lysed mitochondira, as reported in an earlier study. Modal lengths of circles occurred at about 2, 5, and 10 μ Increasing shear degradation also was evident in comparisons of the length-distribution patterns of linear molecules using the three preparative methods. Petite mitochondrial DNA contained 36-38 per cent circular molecules which measured 0.3-5.3 μ, but principally in the range of 0.3 to 2.0 μ whether from chloroform-extracted populations or from ones subfractionated in CsCl. A previous study of osmotically lysed mitochondria had shown a maximum of 8 per cent circles, which we now attribute to a failure, at that time, to detect circles measuring less than 1 μ, a substantial component encountered in the purified DNA samples in the present study. Linear filaments presented a unimodal length distribution in every case.

Despite the variation in molecule populations derived from the three different preparative methods, there were consistent differences between mitochondrial DNA from wild-type and petite yeast in frequencies and size of circular molecules, as well as in length distribution patterns.
DNA-DEPENDENT SYNTHESIS OF RNA BY
Escherichia coli
RNA POLYMERASE: RELEASE AND REINITIATION OF RNA CHAINS FROM DNA TEMPLATES
Authors: Maitra Umadas , Barash Fred
Published: May 2006

RNA synthesis in an
in vitro
RNA polymerase system at low ionic strength soon ceases, due to inhibition by accumulated RNA. Measurement of RNA chain initiation by the incorporation of γ-
32
P-ATP and GTP with native T2 or T4 DNA as template shows that only one RNA chain is formed per molecule of enzyme added. In contrast, when the polymerase reaction is carried out in 10 mM Mg
++
and 0.2
M
KCl, RNA synthesis proceeds nearly linearly for hours, resulting in a marked increase in accumulated RNA. Incorporation of γ-
32
P-ATP also proceeds throughout the course of the reaction and the number of chains initiated per molecule of enzyme is increased severalfold. Most RNA chains formed are released from the DNA template as free RNA. Polymerase is released also in this process and acting catalytically reinitiates new chains. Rifampicin inhibits initiation of RNA synthesis and also blocks reinitiation of RNA chains without affecting growth of RNA chains already initiated.
WIND DIRECTIONS ALOFT AND EFFECTS OF SEEDING ON PRECIPITATION IN THE WHITETOP EXPERIMENT
Authors: Lovasich Jeanne L. , Neyman Jerzy , Scott Elizabeth L. , Smith Jerome A.
Published: May 2006

The subdivision of all the experimental days of the Whitetop project into two approximately equal groups, group
W
with predominantly westerly winds aloft and group
E
with frequent easterly winds, shows a remarkable difference in the apparent effect of seeding. On
W
days there was no detectable effect of seeding on rainfall. On
E
days with seeding, the average 24 hour precipitation in an area of about 100,000 square miles was significantly less than that without seeding by 46 per cent of the latter. The decrease resulted from a “decapitation” of the usual afternoon rise in rainfall. It may be significant that the afternoon maximum of natural precipitation on
E
days occurs some two hours later than on
W
days. If the actual cause of the differences in rainfall was seeding, then the loss of water resulting from operational, rather than experimental, seeding would have averaged eight million acre-feet per summer.
AN IMMUNOLOGICAL APPROACH TO THE STUDY OF EVOLUTION OF TRYPSINS
Authors: Arnon Ruth , Neurath Hans
Published: May 2006

Antibodies were prepared in rabbits against trypsins obtained from four different species—namely bovine, porcine, spiny Pacific dogfish, and starfish (
Evasterias trochelii
). Each of the antisera, or the immunoglobulin G fraction thereof, was tested for its capacity to react with each of the four enzymes. The immunological reaction was assessed by three different techniques—precipitin reaction, antigen binding capacity, and inhibitory effect of the antibodies on the proteolytic activity of the enzymes. In each case, the homologous enzyme gave the strongest reaction with its antiserum but the heterologous enzymes were also capable of reacting to an appreciable extent. The cross-precipitation was the least sensitive method, and gave relatively low values, whereas cross-inhibition and cross-binding of radioactively labeled antigens indicated high extent of cross-reaction between the various trypsins. The relative capacity of interaction of the four enzymes with the four antibodies could be related to the order in which these enzymes developed during evolution. Thus the “order” of similarity was bovine > porcine > dogfish > starfish.
TOLERANCE OF RAT SKIN GRAFTS IN ADULT MICE
Authors: Lance E. M. , Levey R. H. , Medawar P. B. , Ruszkiewicz M.
Published: May 2006

Adult CBA mice may be made tolerant of August rat tail skin grafts by short intensive treatments with antilymphocyte serum followed by massive (∼100 × 10
6
cells) injections of August rat lymphoid cells. Prolonged tolerance can be achieved only in thymectomized mice, and is accompanied by lymphoid cell chimerism and the manufacture of rat protein. The rat lymphoid cell donors must be treated beforehand with antirat ALS to avoid complications associated with graft versus host reactions.

Rejection of rat skin grafts is accompanied by the formation of high titres of antirat hemolysins and lymphocytotoxins, but in “tolerant” mice the rat skin survives in the continual presence of antirat antibodies. Under certain circumstances, however, passive transfusion of high titre mouse antirat serum can precipitate the breakdown of rat skin grafts. It is doubtful if this represents the primary mechanism of rejection. The reaction of normal mice against rat skin is essentially an intensified allograft reaction; it is at all events wholly immunological in character.
Erythropoietic Activity of Steroid Metabolites in Mice
Authors: Gorshein D. , Gardner F. H.
Published: May 2006

The per cent Fe
59
incorporation into circulating erythrocytes as an indicator for new hemoglobin production was used in the polycythemic exhypoxic mouse system to study the effects of certain steroid hormone metabolites on erythropiesis. Enhanced Fe
59
incorporation was observed after the administration of several metabolites with a 5β-H configuration, while those with a 5α-H configuration had no stimulatory effect. The stimulatory effect in avian systems has been shown by others to be due to an increased activity of δ-aminolevulinic acid synthetase, the limiting enzyme in heme biosynthesis. These
in vivo
studies thus indicate that in this mouse system, as in previously reported studies with avian and human bone marrow cells, some steroid metabolites stimulate hemoglobin synthesis. The observation that the same structure-junction relationship exists in the currently described system as in the avian suggests that these steroids probably induce δ-aminolevulinic acid synthetase in the mouse. The erythropoietic action of these nonandrogenic steroid metabolites may prove to be clinically useful.
Unstable Hemoglobins: The Role of Heme Loss in Heinz Body Formation
Authors: Jacob Harry , Winterhalter Kaspar
Published: May 2006

Mutant, unstable hemoglobins precipitate as Heinz bodies in circulating red blood cells resulting in their premature hemolysis. We stress that generally these hemoglobins contain amino acid substitutions in the β-chain of globin near the heme pocket, and demonstrate that heme binding suffers thereby. Four genetically unstable hemoglobins lost roughly half their heme content while precipitating into Heinz bodies. Conversely, repletion of hemes
in vitro
corrected the characteristically aberrant electrophoretic mobilities of these hemoglobins and concomitantly prevented their excessive denaturation into Heinz bodies. From the finding that heme-containing α-chains accumulate in solution during Heinz body formation, we propose that heme loss occurs predominantly from mutant β-chains, which then precipitate. This mechanism of Heinz body formation is valid in most, but not all, the unstable hemoglobinopathies.
Translation-Level Control of Amylase and Protein Synthesis by Epinephrine
Authors: Grand Richard J. , Gross Paul R.
Published: May 2006

The synthesis of RNA, protein, and amylase has been studied in normal and epinephrine-treated slices of rat parotid gland. Epinephrine stimulates synthesis of total cell protein and specifically of amylase, but amylase synthesis is preferentially increased. There is no change in either the specific radioactivity or pattern of labeling of total RNA. In the presence of actinomycin D, epinephrine stimulates secretion of amylase, as well as protein and amylase synthesis. RNA synthesis under these conditions is reduced to 10 per cent of control values. Slices obtained from animals treated with actinomycin D nine and a half hours prior to study show responses to epinephrine comparable to those from control animals, with RNA synthesis inhibited by 70 per cent. Since amylase synthesis is stimulated by epinephrine in the absence of RNA synthesis, control of the production of this enzyme is probably exerted at the level of translation.
The [NeIV] Lines in High Excitation Gaseous Nebulae
Authors: Aller Lawrence H.
Published: May 2006

The „forbidden” lines of three times ionized neon are among the most precious indicators of electron temperature and excitation. They are also predicted to be among the strongest lines observed in the far ultraviolet spectra of high excitation nebulae.
Failure of Energy Transfer between Identical Aromatic Molecules on Excitation at the Long Wave Edge of the Absorption Spectrum
Authors: Weber Gregorio , Shinitzky Meir
Published: May 2006

Electronic energy transfer among identical molecules has been followed by the depolarization of the fluorescence in concentrated solutions as well as in dimers, polymers, and micelle systems. In the many aromatic fluorophores examined, unlike a few nonaromatic ones, transfer is much decreased or altogether undetectable on excitation at the red edge of the absorption spectrum. The phenomenon is not due to the transfer taking place during a small fraction of the total fluorescence lifetime, nor is it explainable by a decrease in overlap of absorption and emission upon edge excitation.
Orientation by Untrained Pigeons Requires the Sun
Authors: Keeton William T. , Gobert Andre
Published: May 2006

Untrained homing pigeons released on sunny days oriented homeward regardless of the direction of the release site from the loft. Similar pigeons released under total overcast vanished randomly, whereas experienced birds released on the same days at the same sites oriented homeward. Apparently untrained pigeons require the sun for orientation but experienced pigeons do not.
Renal Damage Associated with Silicon Compounds in Dogs
Authors: Newberne Paul M. , Wilson Robert B.
Published: May 2006

A number of oral preparations of various forms of silicon were fed to young adult Beagle dogs and young rats of both sexes for a period of four weeks. During the test period the animals were observed for clinical symptoms and urine and blood measurements were made. At the end of the experimental period all animals were sacrificed and subjected to a complete necropsy and histopathologic study. Polydipsia, polyuria, and soft stools in some animals fed sodium silicate and magnesium trisilicate were the only untoward clinical signs observed; all clinical tests on blood and urine were within normal limits. Gross and microscopic renal lesions were observed in dogs fed sodium silicate and magnesium trisilicate but no changes were seen in those animals fed silicon dioxide or aluminium silicate. Lesions were not observed in any of the rats. In view of the large number of commercial preparations which contain sodium silicate and magnesium trisilicate used in human medicine, these compounds deserve further study.
Identity of the 5′-Terminal RNA Nucleotide Sequence of the Satellite Tobacco Necrosis Virus and Its Helper Virus: Possible Role of the 5′-Terminus in the Recognition by Virus-Specific RNA Replicase
Authors: Lesnaw J. A. , Reichmann M. E.
Published: May 2006

A pancreatic ribonuclease digest of
14
C-labeled tobacco necrosis virus RNA was fractionated according to charge by column chromatography. Individual fractions were dephosphorylated with alkaline phosphatase and rechromatographed. The fraction, originally containing oligonucleotides with seven negative charges, separated into two components corresponding to five (-5) and two negative charges (-2). The -5 fraction was derived from the internal oligonucleotides while the -2 fraction must have originated from a 5′-pyrophosphorylated terminal trinucleotide. The sequence of this terminal trinucleotide was determined by column chromatography on DEAE-cellulose in a triethyl ammonium carbonate gradient, using the appropriate markers. The radioactivity chromatographed with a (ApGp)U marker. The order of the Ap and Gp was determined after ribonuclease T
1
and alkaline phosphatase digestion. The radioactivity in the product chromatographed with an ApG marker. The 5′-terminus of tobacco necrosis virus RNA was therefore determined as ppApGpUp..., which is identical to the terminus of the RNA of its satellite virus as previously determined (
J. Mol. Biol.
, 38, 59 (1968);
Science
, 160, 1452 (1968)). The 5′ pyrophosphate in both viruses was probably formed by an
in vivo
enzymatic removal of a γ-phosphate from a triphosphate, and its presence in both viruses suggested a common site of synthesis. The identity of the 5′-terminal sequences is considered not to be fortuitous and is discussed from the standpoint of their role as a recognition site for the virus-specific RNA replicase.
Unit Activity in the Isolated Spinal Cord of Chick Embryo,
in Situ
Authors: Sharma S. C. , Provine R. R. , Hamburger V. , Sandel T. T.
Published: May 2006

Unit electrical activity was recorded from single neurons in the isolated lumbo-sacral spinal cord of 14- to 19-day chick embryos,
in situ
. Spinal cord transection was combined with transection of all lumbo-sacral dorsal roots. The spontaneous discharge of cells is confined, for the most part, to the lower two thirds of the cord. A quasilinear reduction in the number of spontaneously active units was found during the developmental period studied. Comparable results were obtained in decentralized cord with sensory inputs blocked by xylocaine.
Is the Breakdown of the Born-Oppenheimer Approximation Responsible for Internal Conversion in Large Molecules?
Authors: Burland D. M. , Robinson G. W.
Published: May 2006

Vibronic radiationless transitions in large polyatomic molecules can be thought of as a process whereby the molecule, initially prepared in a discrete
quasistationary
state, makes a transition to an adjoining vibronic continuum belonging to a lower electronic state of the same multiplicity. In many instances the transition is analogous to penetration through a barrier between two „nested” potential sheets far away from an actual intersection of the sheets. Simultaneous distortions of vibrational and electronic parts of the wavefunction are required for such a tunneling process. The vibrational distortion manifests itself in the familiar Franck-Condon effect. The electronic distortion can be caused by nontotally symmetric vibrations of the molecule either because of the displaced nuclear configuration, to which the electrons instantly respond (Herzberg-Teller effect), or because of the protracted response of the electrons to the kinetic energy of nuclear motion (nonadiabatic effect or the breakdown of the Born-Oppenheimer approximation). It is found here that Herzberg-Teller coupling is more effective in causing radiationless transitions than the breakdown of the Born-Oppenheimer approximation when the potential surfaces involved are not close to an intersection.
Some Evidence for the Involvement of Adrenergic Sites in the Memory Trace
Authors: Roberts Richard B. , Flexner Josefa B. , Flexner Louis B.
Published: May 2006

Puromycin was injected bitemporally in mice one day after training in a Y-maze. Eight days later various psychotropic drugs were injected intraperitoneally or subcutaneously at maximum tolerable doses. Ten days after the drug injection the mice were tested for their memory of the maze-learning. Memory was lost in control animals injected with saline but restored in most of the animals injected with imipramine, tranylcypromine, or D-amphetamine. Some indication of restoration was observed after injection of reserpine or L-dopa. These results suggest that the blockage caused by puromycin is due to adsorption of peptidyl-puromycin to adrenergic sites and that these sites may be involved in the memory trace.
Linkage between the Poly-L-Lysine Gene and the Locus Controlling the Major Histocompatibility Antigens in Strain 2 Guinea Pigs
Authors: Ellman Leonard , Green Ira , Martin William J. , Benacerraf Baruj
Published: May 2006

The data presented demonstrate linkage between the major histocompatibility locus of inbred strain 2 guinea pigs and a „specific immune response gene,” the PLL gene, which controls responsiveness to poly-L-lysine and hapten conjugates of this polypeptide in these animals. This finding extends to another species and to a different immune system the linkage observed in mice between the H
2
locus and specific immune response genes at the Ir-1 locus. The general significance of the linkage of specific immune response genes to histocompatibility loci is discussed.
Effects of Combined Frontal and Temporal Lesions on Learned Behaviors in Rhesus Monkeys
Authors: Harlow H. F. , Schiltz K. A. , Blomquist A. J. , Thompson C. I.
Published: May 2006

Delayed response ability, and to a lesser extent visual discrimination performance, is seriously impaired by extensive bilateral damage to the frontal lobes. Reciprocal anatomical connections between the frontal and temporal lobes suggested that massive lesions in both lobes might produce an impairment more complete than that resulting from frontal lobectomy alone. Five monkeys were given combined bilateral frontal and anterior-temporal lesions, and were found to be inferior to both frontal lobectomized monkeys and to unoperated controls on the object discrimination task. The combined lesion did not increase the deficit on delayed response over that obtained after only bilateral frontal lobectomy. Results indicate that the anterior-temporal neocortex is involved in the mediation of visual discrimination ability.
Translational Complementarity of RNA Transcripts of Native and Denatured
B. subtilis
DNA
Authors: Cassuto Era , Chargaff Erwin
Published: May 2006

Previous evidence has suggested that the L and H fractions into which denatured DNA of
B. subtilis
can be separated by chromatography are complementary to each other with regard to base compositon, nucleotide sequence, and template properties, and that they may be regarded as families of fragments of the respective DNA strands. The present study tests the proposition that these fractions should also exhibit features of translational complementarity with respect to the DNA-dependent or the RNA-dependent incorporation of amino acids into ribosomes. This has been shown to be the case with the use of two pairs of amino acids: (1) lysine and phenylalanine; (2) proline and glycine.
Chromosome Aberrations among the Yanomama Indians
Authors: Bloom Arthur D. , Neel James V. , Choi Kyoo W. , Iida Shozo , Chagnon Napoleon
Published: May 2006

The chromosomes of leucocytes cultured from the peripheral blood of 49 primitive Yanomama Indians of Venezuela were studied to determine the types and frequencies of aberrations in a human population not exposed to the same exogenous agents as civilized man. In all but one instance, 100 cells per individual were scored. In 13 cases, we found one or more cells with multiple complex breaks and rearrangements, represented by tetracentric, tricentric, and numerous dicentric chromosomes. From the standpoint of chromosomal damage, these cells are among the most abnormal cells yet described
in vivo
in man, and were not seen in the controls. There was also a higher than expected frequency of cells with an isolated structural aberration in both Indians and controls. This may be the result of a 24- to 48-hour delay in the initiation of culture. The cause of the more extensive damage to some cells remains to be determined.
SPECIFIC BINDING OF LEUCYL TRANSFER RNA TO AN IMMATURE FORM OF L-THREONINE DEAMINASE: ITS IMPLICATIONS IN REPRESSION
Authors: Hatfield G. Wesley , Burns R. O.
Published: May 2006

The
in vitro
assembly of L-threonine deaminase from its constituent parts results in the formation of an inactive species of this enzyme which specifically and reversibly binds leucyl-tRNA. The native, catalytically active enzyme, which is derived from this species in the presence of maturation-inducing ligands, does not bind tRNA. The possible involvement of this protein-tRNA complex in the repression of the
ilv
(ADE) operon is discussed.
GENETIC CONTROL OF THE IMMUNE RESPONSE OF GUINEA PIGS TO LIMITING DOSES OF BOVINE SERUM ALBUMIN: RELATIONSHIP TO THE POLY-L-LYSINE GENE
Authors: Green I. , Inman J. K. , Benacerraf B.
Published: May 2006

The response of strain 2 guinea pigs to limiting doses of bovine serum albumin is under dominant genetic control linked with the poly-L-lysine gene. Inbred strains 2 and 13 guinea pigs make similar antibody responses to 10 μg bovine serum albumin, whereas strain 2 but not strain 13 animals produce significant amounts of antibodies in response to 0.1 μg. The relationship between the presence of the poly-L-lysine gene and the ability to respond to limiting doses of bovine serum albumin has also been investigated in random-bred Hartley strain guinea pigs.
Degradation of a Pneumococcal Type-Specific Polysaccharide with Exposure of Group-Specificity
Authors: Higginbotham John D. , Heidelberger Michael , Gotschlich Emil C.
Published: May 2006

Pyruvic acid is an immunological determinant of the quite rigorously type-specific capsular polysaccharide of pneumococcal type IV (S IV). Removal of pyruvic acid by mild hydrolysis converts the capsular polysaccharide of type IV into an analog of the pneumococcal group-specific C-substance. Depyruvylated S IV resembles C-substance so closely immunologically that it not only precipitates a high proportion of the anti-C in antipneumococcal sera, regardless of their immunological types, but also, like C, precipitates human C-reactive protein in the presence of calcium ions. Apparently, the removal of pyruvic acid ketal rings from adjacent sugars unmasks
N
-acetylgalactosamine residues which must be linked and spaced much as are those in C-substance. Groupings reactive with suitably linked
N
-acetylgalactosamine, therefore, appear to be located on the surfaces of molecules of human C-reactive protein.
Conversion of Glycogen Phosphorylase
b
to
a
by Non-Activated Phosphorylase
b
Kinase: an
In Vitro
Model of the Mechanism of Increase in Phosphorylase
a
Activity with Muscle Contraction
Authors: Villar-Palasi C. , Wei S. H.
Published: May 2006

Phosphorylase
b
kinase activity, as present in resting muscle in the non-activated form, appears to be ample to account for the fast appearance of phosphorylase
a
observed with muscle contraction. The kinase activity is repressed by free ATP and stimulated by free Mg
2+
. Phosphorylase
b
kinase activity increases greatly when the Mg
2+
:ATP ration exceeds 1. It is proposed that the breakdown of ATP that occurs during muscle contraction may represent the triggering factor for the observed
in vivo
conversion of phosphorylase
b
into
a
.
Mechanism of Activation by Adenosine 3′:5′-Cyclic Monophosphate of a Protein Phosphokinase from Rabbit Reticulocytes
Authors: Tao Mariano , Salas Maria L. , Lipmann Fritz
Published: May 2006

Two protein phosphokinases (EC 2.7.1.37) were found to be present in rabbit reticulocytes. The two enzymes were separated by DEAE-cellulose chromatography and called kinases I and II. Adenosien 3′:5′-cyclic monophosphate stimulated the activity of both enzymes. However, the degree of stimulation was different and depended on the protein acceptor used. In the presence of adenosine 3′:5′-cyclic monophosphate, protein kinase I dissociated into two subunits: a subunit binding adenosine 3′:5′-cyclic monophosphate, and a catalytic subunit. The component binding the cyclic nucleotide appeared to act as an inhibitory protein, regulating the activity of the catalytic subunit. The mechanism of action of the cyclic nucleotide on kinase II appeared to be different from that of kinase I.
Mutations Altering Chloroplast Ribosome Phenotype in
Chlamydomonas
, I. Non-Mendelian Mutations
Authors: Gillham Nicholas W. , Boynton John E. , Burkholder Barbara
Published: May 2006

Uniparentally inherited mutations to antibiotic resistance and dependence in
Chlamydomonas reinhardi
exhibit an altered chloroplast ribosome phenotype. Genetic studies demonstrate an absolute correlation between the drug resistance or dependence and the ribosome phenotype in two such mutants.
A Factor for the Binding of Aminoacyl Transfer RNA to Mammalian 40S Ribosomal Subunits
Authors: Leader David P. , Wool Ira G. , Castles James J.
Published: May 2006

A factor present in rat liver supernatant catalyzes binding of Phe-tRNA to 40S ribosomal subunits from rat skeletal muscle. This factor could be distinguished from aminoacyltransferase I by a number of criteria: (1) at lower concentrations of magnesium (5 mM) the 40S binding factor was approximately seven times as effective as T-I in catalyzing binding of Phe-tRNA to 40S subunits; (2) the kinetics of the binding reaction were different when catalyzed by the 40S binding factor, in particular the initial rate was greater than in the presence of T-I—indeed, the kinetics of the T-I catalyzed reaction resembled nonenzymic binding; (3) GTP was required for maximal binding of Phe-tRNA to 40S subunits in the presence of the 40S binding factor, but not for the T-I catalyzed reaction; (4) the 40S binding factor was inactivated by
N
-ethylmaleimide whereas T-I was not; (5) finally, the 40S binding factor was more susceptible to heat inactivation. Binding of aminoacyl-tRNA to 40S ribosomal subunits may be a paradigm for the initiation of protein synthesis, and the 40S binding factor may play a role in the process.
A Possible Role of Phospholipid in Nerve Excitation
Authors: Wang Jui H.
Published: May 2006

A possible role of phospholipid in regulating the ionic permeability of excitable membranes is proposed. It is assumed that each excitable transport channel in the nerve fiber is lined with two chains of phospholipid dipoles in either parallel or antiparallel directions; a molecular mechanism of nerve excitation is developed that is qualitatively consistent with most of the relevant observations reported in the literature.
Phonoangiography: A New Noninvasive Diagnostic Method for Studying Arterial Disease
Authors: Lees Robert S. , Dewey C. Forbes
Published: May 2006

Phonoangiography, the quantitative analysis of sounds produced by blood flow, has been used to investigate local fluid motion in arteries narrowed by atherosclerosis. The sound spectra measured
in vivo
were found to be identical to those obtained in laboratory investigations of turbulent pipe flow. A theoretical model is proposed which: (
a
) quantitatively relates the
in vivo
and
in vitro
data, and (
b
) allows estimation of the clinically important parameters of arterial diameter, flow velocity, local turbulence intensity, and wall pressure fluctuations. The results of calculations using data from human subjects agree with known arterial diameters and blood flow velocities.
Selection of a Single Antibody-Forming Cell Clone and Its Propagation in Syngeneic Mice
Authors: Askonas B. A. , Williamson A. R. , Wright B. E. G.
Published: May 2006

A single antibody-forming cell clone has been selected from primed mice by sequential transfer of limited numbers of spleen cells into irradiated syngeneic mice. The original spleen cell donors had been immunized with dinitrophenylated bovine gamma globulin. Specific antibody molecules in sera of recipient mice were separated by isoelectric focusing on polyacrylamide gels and visualized by
131
I-hapten binding and autoradiography. This method provided a marker for antibody-forming cells derived from a single cell clone. This report describes the history of one clone of cells (E9) producing IgG antibody to dinitrophenyl. Clone E9 is long-lived and has been maintained for five transplant generations (over 6 months) by serial transfer of spleen cells into irradiated syngeneic mice. Clone E9 has the following properties: (1) Antibody production strictly depends on antigen, presented either
in vivo
or
in vitro;
(2) Induction of E9 anti-dinitrophenyl shows specificity for the carrier protein; (3) Antibody is produced in amounts (2-3 mg/ml serum) comparable with myeloma-protein production by murine plasmacytomas; (4) In the absence of antigen, memory cells have a lifetime exceeding 28 days.
Electron Spin Resonance Studies of Carbonic Anhydrase: Transition Metal Ions and Spin-Labeled Sulfonamides
Authors: Taylor June S. , Mushak Paul , Coleman Joseph E.
Published: May 2006

Electron spin resonance (esr) spectra of Cu(II) and Co(II) carbonic anhydrase, and a spin-labeled sulfonamide complex of the Zn(II) enzyme, are reported. The coordination geometry of Cu(II) bound in the enzyme appears to have approximately axial symmetry. Esr spectra of enzyme complexes with metal-binding anions also show axial symmetry and greater covalency, in the order ethoxzolamide < SH
-
< N
3
-
≤ CN
-
. Well-resolved superhyperfine structure in the spectrum of the cyanide complex suggests the presence of two, and probably three, equivalent nitrogen ligands from the protein. Esr spectra of the Co(II) enzyme and its complexes show two types of Co(II) environment, one typical of the native enzyme and the 1:1 CN
-
complex, and one typical of a 2:1 CN
-
complex. Co(II) in the 2:1 complex appears to be low-spin and probably has a coordination number of 5. Binding of a spin-labeled sulfonamide to the active center immobilizes the free radical. The similarity of the esr spectra of spin-labeled Zn(II) and Co(II) carbonic anhydrases suggests that the conformation at the active center is similar in the two metal derivatives.