bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Chronic Ethanol Administration on Rat Brain Phospholipid Metabolism
Authors: Sun Grace Y. , Huang Hsueh‐Meei , Chandrasekhar Renuka , Lee Ding Z. , Sun Albert Y.
Published: October 2006

Abstract: Alterations in brain phospholipid metabolism were observed after chronic ethanol administration for 16 days to developing rats. Animals were injected intraperitoneally with 32Pi 16 h prior to killing. Overall uptake of 32Pi by brain did not differ between the control and ethanol‐treated groups, which were killed 2 h and 24 h after the last ethanol feeding. Except for an increase in the labeling of myelin after ethanoi treatment, the amount of radioactivity recovered in the synaptosomal‐mitochondrial and plasma membrane fractions of control and ethanol‐treated groups was not different. Relative to the radioactivity of phosphatidylcholines, which indicated no change, there were increases (20–44%) in labeling of ethanolamine plasmalogens, phosphatidic acids, and phosphatidylinositols in cortical synaptosomes from the 2‐h ethanol‐treated group. In the plasma membrane fractions, however, increases (9–14%) in labeling of phosphatidylserines and phosphatidylinositols were observed in both 2‐ and 24‐h ethanol‐treated groups. In both membrane fractions, there was an obvious increase (44–86%) in labeling of polyphosphoinositides at 24 h after withdrawal from ethanol. Results thus indicate an adaptive increase in the biosynthesis of ethanolamine plasmalogen and brain acidic phospholipids due to chronic ethanol administration. Furthermore, the increase in labeling of polyphosphoinositides in the 24‐h withdrawal group may reflect the hypoactivity associated with ethanol withdrawal.
Properties of Quisqualate‐Sensitive L‐[3H]Glutamate Binding Sites in Rat Brain as Determined by Quantitative Autoradiography
Authors: Cha Jang‐Ho J. , Timothy Greenamyre J. , Nielsen Elsebet Ø. , Penney John B. , Young Anne B.
Published: October 2006

Abstract: Quisqualate, a glutamate analogue, displaced L‐[3H]glutamate binding in a biphasic manner, corresponding to “high‐affinity” and “low‐affinity” binding sites. High‐affinity quisqualate sites were termed “quisqualate‐sensitive L‐[3H]glutamate” binding sites. Quisqualate‐sen‐sitive L‐[3H]glutamate binding was regionally distributed, with the highest levels present in the cerebellar molecular layer. This binding was stimulated by millimolar concentrations of chloride and calcium. The stimulatory effects of calcium required the presence of chloride ions, whereas chloride's stimulatory effects did not require calcium. All of the L‐[3H]glutamate binding stimulated by chloride/calcium was quisqualate sensitive and only weakly displaced by N‐methyl‐D‐aspartate, L‐aspartate, or kainate. At high concentrations (1 mM), the anion blockers 4‐acetamido‐4′‐isothiocyanostilbene‐2,2′‐disulfonic acid and4,4′‐diisothio‐cyanatostilbene‐2,2′‐disulfonic acid both reduced, by 41 and 43%, respectively, the stimulatory effects of chloride. At concentrations of 100 μM, kynurenate, L‐aspartate, (RS)‐α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid (AMPA), and L‐2‐amino‐4‐phosphonobutyric acid (L‐APB) failed to displace quisqualate‐sensitive L‐[3H]‐glutamate binding in the cerebellar molecular layer. In the presence of KSCN, however, 100 μM AMPA displaced 44% of binding. Quisqualate‐sensitive L‐[3H]glutamate binding was not sensitive to freezing, and, in contrast to other chloride‐ and calcium‐dependent L‐[3H]glutamate binding sites that have been reported, quisqualate‐sensitive binding observed by autoradiography was enhanced at 4°C compared with 37°C. Quisqualate‐sensitive L‐[3H]glutamate binding likely represents binding to the subclass of postsynaptic neuronal glutamate receptors known as quisqualate receptors, rather than binding to previously described APB receptors, chloride‐driven sequestration into vesicles, or binding to astrocytic membrane binding sites.
Properties of the 12‐O‐Tetradecanoylphorbol‐13‐Acetate‐Stimulated S6 Kinase from Rat Astroglial Cells
Authors: Toru‐Delbauffe Danièle , Gavaret Jean‐Michel , Jacquemin Claude , Matricon Carole , Pomerance Martine , Pierre Michel
Published: October 2006

Abstract: The S6 kinase activity of astroglial cells in primary culture stimulated by 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) has been studied. This activity was eluted as a single peak at 0.15 M NaCl from a DEAE‐Sephacel column. The chromatography of this peak on phosphocellulose revealed an activity eluted at 0.15 M NaCl. This partially purified enzyme had a sedimentation coefficient of 3.7S; Km values were 2 × 10−5M for ATP and 10−6M for 40S ribosomal subunits. The optimal Mg2+ concentration requirement was 2‐3 mM. Mn2+ and Co2+ could substitute for Mg2+ (optimum concentrations 1.5 and 0.8 mM, respectively), but these cations were strong inhibitors in the presence of Mg2+. The enzyme was inhibited by N‐ethylmaleimide, indicating that it contained thiol groups. This S6 kinase used ATP, but not GTP, as a phosphate donor, and exhibited great specificity for S6 as phosphate acceptor. Whole histones and protamine were slightly phosphorylated whereas phosvitin, histone H1. and surprisingly the peptide Arg‐Arg‐Leu‐Ser‐Ser‐Leu‐Arg‐Ala were not phosphorylated. The TPA‐stimulated S6 kinase resembles the insulin‐, fibroblast growth factor‐ and cyclic AMP‐stimulated enzymes, suggesting that several pathways might activate the same entity.
[3H]Tryptamine Binding Sites Are Not Identical to Monoamine Oxidase in Rat Brain
Authors: Perry David C. , Grimm Linda J. , Kettler Karen G. , Kellar Kenneth J.
Published: October 2006

Abstract: Competition binding studies, subcellular distribution, and in vitro autoradiography were employed to compare the binding in rat brain of [3H]tryptamine with two radio‐ligands for monoamine oxidase (MAO), [3H]pargyline, and [3H] 1 ‐methyl‐4‐phenyl‐1,2,5,6‐tetrahydropyridine ([3H]MPTP). The MAO inhibitors pargyline, clorgyline, and deprenyl all yielded biphasic competition curves versus [3H]tryptamine. At low concentrations, these drugs stimulated binding by protecting the radioligand from MAO oxidation; at considerably higher concentrations, they inhibited binding by direct competition at the [3H]tryptamine binding site. In subcellular distribution studies, [3H]tryptamine was localized preferentially to the synaptosomal fraction, whereas [3H]pargyline showed greater binding to the mitochondrial fraction. Equilibrium binding studies revealed that the potencies of a series of seven compounds at inhibiting [3H]tryptamine binding were completely different from their potencies at inhibiting [3H]MPTP binding. Finally, the au‐toradiographic distribution of [3H]tryptamine binding in rat brain v/as different from that of [3H]MPTP and [3H]pargyline. We conclude that the [3H]tryptamine binding site in rat brain is not equivalent to MAO.
Stability and Activation of Glutamate Apodecarboxylase from Pig Brain
Authors: Porter Terence G. , Martin David L.
Published: October 2006

Abstract: The stability and activation of glutamate apodecarboxylase was studied with three forms of the enzyme from pig brain (referred to as the α, β, and γ forms). Apoenzyme was prepared by incubating the holoenzyme with aspartate followed by chromatography on Sephadex G‐25. Apoenzyme was much less stable than holoenzyme to inactivation by heat (for β‐glutamate decarboxylase (β‐GAD) at 30°C, tl/2 values of apo‐ and holoenzyme were 17 and > 100 min). ATP protected holoenzyme and apoenzyme against heat inactivation. The kinetics of reactivation of apoenzyme by pyridoxal‐P was consistent with a two‐step mechanism comprised of a rapid, reversible association of the cofactor with apoenzyme followed by a slow conversion of the complex to active holoenzyme. The reactivation rate constant (Kr) and apparent dissociation constant (KD) for the binding of pyridoxal‐P to the apoenzyme differed substantially among the forms (for α‐, β‐, and γ‐GAD, kr= 0.032, 0.17, and 0.27 min−1, and KD= 0.014, 0.018, and 0.04 μM). ATP was a strong competitive inhibitor of activation (Ki= 0.45, 0.18, and 0.39 μM for α‐, β‐, and γ‐GAD). In contrast, Pi stimulated activation at 1–5 mM but inhibited at much higher concentrations. The results suggest that ATP is important in stabilizing the apoenzyme in brain and that ATP, Pi, and other compounds regulate its activation.
Excess K+ and Phorbol Ester Activate Protein Kinase C and Support the Survival of Chick Sympathetic Neurons in Culture
Authors: Wakade Arun R. , Wakade Taruna D. , Malhotra Ravindra K. , Bhave Sanjiv V.
Published: October 2006

Abstract: The effects of phorbol esters were investigated on the survival of chick sympathetic neurons in a serum‐free culture medium. The protein kinase C activator phorbol 12,13‐dibutyrate (PDB) supported about 40% of the plated sympathetic neurons. This number was comparable to that supported by nerve growth factor (NGF). A combination of phorbol ester and NGF did not significantly increase the number of surviving neurons. Phorbol ester‐supported sympathetic neurons possessed desipramine‐sensitive [3H]‐norepinephrine uptake mechanism, and therefore were noradrenergic in character. Two days after the start of cultures, if NGF was replaced by phorbol ester, or phorbol ester was replaced by NGF, the number of surviving sympathetic neurons was essentially the same in both groups, and the uptake of [3H]norepinephrine was also comparable when examined 2 days after the switchover. Interchangeability between phorbol ester and NGF in the survival of sympathetic neurons suggests that both agents act on the same subpopulation of neurons of the chick sympathetic ganglia. The protein kinase C activity of cytosol and particulate fractions of NGF‐supported neurons was 0.14 and 0.09 pmol/min/mg protein, respectively. In phorbol estersupported neurons the activity in the paniculate fraction increased by about fivefold. Removal of the phorbol ester after 2 days resulted in restoration of the enzyme activity in <1 h, and readdition of the phorbol ester again increased the activity by fivefold. When NGF was added to these neurons (1 μg for 15 min), there was no change in the enzyme activity. Phorbol 13‐acetate was ineffective in supporting sympathetic neurons in culture, as well as in enhancing protein kinase C activity. We also compared the protein kinase C activity of sympathetic neurons supported in culture by NGF and excess potassium (35 mM K+). Neurons supported in culture by 35 mM K+ for 2 days had almost eightfold more protein kinase C activity in their particulate fraction than in cytosol fraction. If NGF‐supported neurons were acutely treated with excess K+, the protein kinase C activity was increased in the particulate fraction by about sevenfold in a concentration‐ and time‐dependent manner. Excess K+ plus phorbol ester did not produce an additive effect on protein kinase C activity. PDB and excess K+ had no effect on cyclic AMP content of sympathetic neurons. In summary, the present data suggest that the neurotrophic action of PDB and excess K+ is probably mediated through protein kinase C.
Kinetics of the Hydrolysis of 8‐Bromo‐Cyclic GMP by the Light‐Activated Phosphodiesterase of Toad Rods
Authors: Barkdoll A. E. , Pugh E. N. , Sitaramayya A.
Published: October 2006

The hypothesis that cyclic GMP is the internal transmitter of retinal rod phototransduction, when combined with the observations that 8‐bromo‐cyclic GMP opens the cyclic GMP‐dependent outer segment conductance and that rods into which 8‐bromo‐cyclic GMP has been injected still respond to light, predicts that the light‐activated phosphodiesterase (EC 3.1.4.17) must catalyze the hydrolysis of 8‐bromo‐cyclic GMP. This hypothesis was tested by measuring light‐activated toad rod disk membrane phosphodiesterase with a pH assay technique. Phos‐phodiesterase‐catalyzed hydrolysis of 8‐bromo‐cyclic GMP was confirmed: at pH 8.0, total proton production after flash activation was identical to total amount of 8‐bromo‐cyclic GMP added as substrate. Photoactivated phosphodiesterase was remarkably less efficient in catalyzing the hydrolysis of 8‐bromo‐cyclic GMP than of cyclic GMP: Vmax for 8‐bromo‐cyclic GMP was 0.063 M/M rhodopsin/s, whereas that for cyclic GMP was 11 M/M rhodopsin/s—170 times greater. The Km for 8‐bromo‐cyclic GMP was 160 nM, and for cyclic GMP, 590 μM. 8‐Bromo‐cyclic GMP competitively inhibited phosphodiesterase‐catalyzed hydrolysis of cyclic GMP with a Ki of 1.2 mM. Complete reaction progress curves were analyzed for obedience to Michaelis‐Menten kinetics: cyclic GMP hydrolysis, 8‐bromo‐cyclic GMP hydrolysis, and cyclic GMP hydrolysis in the presence of 8‐bromo‐cyclic GMP as competitive inhibitor were found to follow the integrated form of the Michaelis‐Menten equation over the time course of the reactions, assuming phosphodiesterase was activated as a step. The kinetic parameters extracted from reaction progress curves were consistent with those derived from analysis of the initial velocity. Our results lead to quantitative predictions about the photocurrents of rods into which 8‐bromo‐cyclic GMP and cyclic GMP are infused: these predictions are discussed.
Regulation of Central Cholecystokinin Recognition Sites by Guanyl Nucleotides
Authors: Wennogle L. , Wysowskyj H. , Steel D. J. , Petrack B.
Published: October 2006

Guanyl nucleotides affected the binding of radio‐labeled cholecystokinin (CCK) octapeptide to rodent cortical binding sites. Micromolar quantities of a stable GTP analogue, guanylyl‐imidodiphosphate (GppNp), resulted in a plateau where binding was decreased by 30%. In the presence of 25 μM GppNp, binding analysis revealed a decrease in affinity (increase in KD), without an apparent effect on the maximal number of binding sites. Ki values for CCK‐related peptides shifted up to 1.6‐fold. The rate of peptide association decreased by threefold, and the rapid component of peptide dissociation increased. The collective data suggest that a class of central CCK binding sites is linked to nucleotide regulatory proteins. The evidence is discussed with regard to multiple receptor populations and to possible interconversions between receptor types.
Isolation and Sequence of a cDNA Clone of β‐Nerve Growth Factor from the Guinea Pig Prostate Gland
Authors: Schwarz Martin A. , Fisher Douglas , Bradshaw Ralph A. , Isackson Paul J.
Published: October 2006

Abstract The guinea pig prostate gland contains high levels of nerve growth factor similarly to the mouse submandibular gland. Nerve growth factor from the guinea pig prostate gland cross‐reacts weakly with antisera directed against mouse nerve growth factor, is associated with different proteins, and may be processed by a different mechanism. We have isolated a full‐length cDNA clone for nerve growth factor from a library prepared from RNA of the guinea pig prostate gland. The guinea pig cDNA contains 1,075 nucleotides and is very similar to the shorter of two predominant nerve growth factor transcripts present in the mouse submandibular gland. The cDNA sequence predicts a precursor protein of 241 amino acids that is 86% identical to the mouse amino acid sequence. Only 10 amino acid changes are present in the C‐terminal region corresponding to the mature 118 amino acid β‐nerve growth factor of the mouse. Dibasic amino acid processing sites that are present at the N‐ and C‐termini of the mature protein sequence and two other dibasic amino acid sites, representing potential processing sites within the propeptide, are all conserved, suggesting a similar mechanism of processing.
Postnatal Development and Possible Ligand Function of the CNS‐Specific Membrane Glycoprotein CNSgp 130
Authors: Flanagan Brian F. , Fabre John W.
Published: October 2006

Abstract: CNSgp 130 is a CNS‐specific membrane glycoprotein present in large amounts in the adult mammalian CNS. Using immunohistological techniques, we demonstrated that CNSgp 130 is not detectable in the rat cerebellum at birth, and does not appear in the cerebellum until the tenth day of postnatal life. It is expressed first in the white matter of the cerebellar folia, and subsequently (by day 14) it is expressed also in the molecular layer. Expression in the granular layer is not seen until the 18th day of postnatal life, by which time the adult pattern of expression is established. CNSgp 130 is also not detectable in the cerebrum at birth. However, it is expressed weakly but diffusely in the cerebrum by the fourth day of life. By the 10th day, there is strong expression in the cerebrum, in marked contrast to its virtual absence from the cerebellum at this stage. By quantitative absorption analysis, CNSgp 130 was undetectable on the day of birth, and increased steadily to 80% of adult values by the 22nd day of postnatal life. Binding studies with pure CNSgp 130 demonstrated a Pronase‐sensitive ligand in adult chicken brain. This ligand was absent from neonatal rat brain and non‐CNS tissues.
Coordinate Regulation of Ganglioside Glycosyltransferases in Differentiating NG108‐15 Neuroblastoma X Glioma Cells
Authors: Walton Kevin M. , Schnaar Ronald L.
Published: October 2006

Abstract: The enzymatic basis for ganglioside regulation during differentiation of NG108‐15 mouse neuroblastoma X rat glioma hybrid cells was studied. This cell line contains four gangliosides that lie along the same biosynthetic pathway: GM3, GM2, GM1, and GD1a. Chemically induced neuronal differentiation of NG108‐15 cells led to an 80% drop in the steady‐state level of their major ganglioside, GM3, a sixfold increase in the level of a minor ganglioside, GM2 (which became the predominant ganglioside of differentiated cells); and relatively little change in the levels of GM1 and GD1a, which lie further along the same biosynthetic pathway. The enzymatic basis for this selective change in ganglioside expression was investigated by measuring the activity of two glycosyltransferases involved in ganglioside biosynthesis. UDP‐N‐acetylgalactosamine:GM3 N‐acetylgalactosaminyltransferase (GM2‐synthetase) activity increased fivefold during butyrate‐induced differentiation, whereas UDP‐galactose: GM2 galactosyltransferase (GM1‐synthetase) activity decreased to 10% of its control level. Coordinate regulation of these two glycosyltransferases appears to be primarily responsible for the selective increase of GM2 expression during NG108‐15 differentiation.
Interactions Between α‐Latrotoxin and Trivalent Cations in Rat Striatal Synaptosomal Preparations
Authors: Scheer H. W.
Published: October 2006

Abstract: The interactions between α‐latrotoxin (α‐LTx), a neurosecretagogue purified from the venom of the black widow spider, and the trivalent cations Al3+, Y3+, La3+, Gd3+, and Yb3+ were investigated in rat striatal synaptosomal preparations. All trivalent cations tested were inhibitors of α‐LTx‐induced [3H]dopamine ([3H]DA) release (order of potency: Yb3+ > Gd3+± Y3+ > La3+ > Al3+). Only with Al3+ could inhibition of [3H]DA release be attributed to a block of 125I‐α‐LTx specific binding to synaptosomal preparations. The inhibitory effect of trivalent ions was reversible provided synaptosomes were washed with buffer containing EDTA. Trivalent ions also inhibited α‐LTx‐induced [3H]DA release at times when α‐LTx‐stimulated release was already evident. α‐LTx‐induced synaptosomal membrane depolarization was blocked by La3+, but not affected by Gd3+, Y3+, and Yb3+. α‐LTx‐stimulated uptake of 45Ca2+ was inhibited by all trivalent cations tested. These results demonstrate that there exist at least three means by which trivalent cations can inhibit α‐LTx action in rat striatal synaptosomal preparations: (1) inhibition of α‐LTx binding (Al3+); (2) inhibition of α‐LTx‐induced depolarization (La3+); and (3) inhibition of α‐LTx‐induced 45Ca2+ uptake (Gd3+, Y3+, Yb3+, La3+).
Insulin Binding to Human Astrocytoma Cells and Its Effect on Uridine Incorporation into Nucleic Acid
Authors: Kum W. , Cockram C. S. , Zhu S. Q. , Teoh R. , Young J. D.
Published: October 2006

Abstract: Binding of [125I]monoiodoinsulin to human astrocytoma cells (U‐373 MG) was time dependent, reaching equilibrium after 1 h at 22°C with equilibrium binding corresponding to 2.2 fmol/mg protein: this represents approximately 2,000 occupied binding sites per cell. The t1/2 of 125I‐insulin dissociation at 22°C was 10 min; the dissociation rate constant of 1.1 × 10−2 s−1 was unaffected by a high concentration of unlabeled insulin (16.7 μM). Porcine insulin competed for specific 125I‐insulin binding in a dose‐dependent manner and Scatchard analysis suggested multiple affinity binding sites (higher affinity Ka= 4.4 × 108M−1 and lower affinity Ka= 7.4 × 106M−1). Glucagon and somatostatin did not compete for specific insulin binding. Incubation of cells with insulin (0.5 μM) for 2 h at 37°C increased [2‐14C]uridine incorporation into nucleic acid by 62 ± 2% (n = 3) above basal. Cyclic AMP, in the absence of insulin, also stimulated nucleoside incorporation into nucleic acid [65 ± 1% (n = 3)] above basal. Preincubation with cyclic AMP followed by insulin had an additive effect on nucleoside incorporation [160 ± 4% (n = 3) above basal]. Dipyridamole (50 μM), a nucleoside transport inhibitor, blocked both basal and stimulated uridine incorporation. These studies confirm that human astrocytoma cells possess specific insulin receptors with a demonstrable effect of ligand binding on uridine incorporation into nucleic acid.
Interactions of the Complex Secretory Vesicle Binding Protein Chromobindin A with Nucleotides
Authors: Martin William H. , Creutz Carl E.
Published: October 2006

Chromobindin A is a large, multisubunit protein that binds to chromaffin granule membranes in a Ca2+‐ and ATP‐regulated manner. Ca2+ stimulates binding to the membrane, whereas ATP, in the absence of Ca2+, is required for release of the protein from the membrane. We now report that spectral and HPLC data indicate that nucleotides are associated with the native chromobindin A complex and that the protein can bind two molecules of [3H]ATP in vitro. Chromobindin A also appears to be a novel nucleotide triphosphatase. ATPase activity was detected in fractions containing chromobindin A isolated by affinity chromatography, gel filtration, or ion exchange chromatography. Kinetic studies indicated that the Vmax is 44 nmol of Pi/mg/min and the Km is 0.115 mM, whereas the nonhydrolyzable ATP analog 5′‐adenylylimidodiphosphate acts as a competitive inhibitor of this reaction with a Ki of 0.08 mM. The activity was found to be sensitive to protease treatment or to preincubation at 65°C and was inhibited by Ca2+ or low pH. The ATPase activity was not inhibited by N‐ethylmaleimide, N,N'‐dicyclohexylcarbodiimide, vanadate, oligomycin, or azide.
Antileukemic Principles Isolated from Euphorbiaceae Plants
Authors: Kupchan S. Morris , Uchida I. , Branfman A. R. , Dailey R. G. , Fei B. Yu
Published: October 2006

Extracts of
Euphorbia esula
L. and
Croton tiglium
L., two members of the Euphorbiaceae which have been used widely in folk medicine for treating cancers, showed antileukemic activity against the P-388 lymphocytic leukemia in mice. Systematic fractionation of the extract of
Euphorbia esula
L. led to characterization of a major antileukemic component as the new diterpenoid diester, ingenol 3,20-dibenzoate. Similar fractionation of
Croton
oil led to characterization of phorbol 12-tiglate 13-decanoate as an active principle.
Oxygen Isotope Paleotemperature Determinations of Australian Cainozoic Fossils
Authors: Dorman F. H. , Gill Edmund D.
Published: October 2006

Fossil marine shells collected in southern Victoria within half a degree of latitude of 38½ °S have been analyzed for O
18
/O
16
by mass spectroscopy, and their paleotemperatures have been determined. For the genera
Chlamys
,
Ostrea
, and
Glycymeris
the temperature rises from early to mid-Tertiary, then falls again to the present.
Carbon-14 Dating with the Liquid Scintillation Counter: Total Synthesis of the Benzene Solvent
Authors: Tamers Murry A.
Published: October 2006

Samples are analyzed for natural radiocarbon content by a total synthesis of benzene from their organic constituents. The benzene is employed as the solvent in a liquid scintillation counter. The instrument used permits 15 grams of carbon to be counted with an efficiency of 40 percent and a background of 13 counts per minute.
Appearance of a Spring Maximum in Nuclear Test Debris in 1960
Authors: Gustafson P. F. , Brar S. S. , Kerrigan M. A.
Published: October 2006

The existence of a spring maximum in fallout deposition due to the disruption of the tropopause in middle latitudes has been debated for the past several years. Evidence obtained from air filters indicates elevated levels of radioactivity from nuclear tests in surface air during April through July 1960.
Vessels in Roots of
Marsilea
Authors: White Richard A.
Published: October 2006

The occurrence of vessel members in the roots and the possible occurrence of sieve-tube members in the rhizome is reported for the first time in the heterosporous fern
Marsilea quadrifolia.
This discovery adds a new instance of parallel evolution of vessels in vascular plants.
Possible Transpacific Contact on the Coast of Ecuador
Authors: Estrada Emilio , Meggers Betty J. , Evans Clifford
Published: October 2006

The earliest pottery-producing culture on the coast of Ecuador, the Valdivia culture, shows many striking similarities in decoration and vessel shape to pottery of eastern Asia. In Japan, resemblances are closest to the Middle Jomon period. Both early Valdivia and Middle Jomon are dated between 2000 and 3000 B.C. A transpacific contact from Asia to Ecuador during this time is postulated.
Natural Triploidy in Salamanders Related to
Ambystoma jeffersonianum
Authors: Uzzell Thomas M.
Published: October 2006

Female salamanders with large erythrocytes and erythrocyte nuclei produced triploid larvae; females with small erythrocytes and erythrocyte nuclei produced diploid larvae. Larval chromosome counts, dimorphism in cell size, and sex inheritance indicate distinct, persisting populations of triploid females in parts of the range of the
Ambystoma jeffersonianum
complex.
Synapse Arising at Central Node of Ranvier, and Note on Fixation of the Central Nervous System
Authors: Bodian David , Taylor Naomi
Published: October 2006

The discovery in electron micrographs of a synaptic bouton arising directly from a node of Ranvier in the motor horn of the monkey spinal cord, and of a node covered by extensions of two outer lamellae of the myelin sheath, suggests a degree of variation of central nodal structure and development not usually attributed to nodes of Ranvier.
Low-Latitude Noctilucent Cloud of 2 November 1963
Authors: Meinel Aden B. , Meinel Carolyn P.
Published: October 2006

Measurement of the filamentary noctilucent cloud of 2 November 1963 yields a height of 56 km. Study of the motion and orientation of the cloud confirms the hypothesis that these unusual clouds appearing in the southwestern states are produced by the launching of rocket vehicles from the Pacific Missile Range.
DNA Segregation in
Escherichia coli
: Observations by Means of Tritiated Thymidine Decay
Authors: Person Stanley , Osborn Mary
Published: October 2006

Escherichia coli
, strain 15
T-L-
, inactivation by H
3
-thymidine decay was used in a study of DNA segregation. Two characteristics of the inactivation curves due to H
3
-thymidine decay, the initial slope and stable fraction, enable the mode of segregation to be defined. The results suggest that the segregation pattern is consistent with a semiconservative model of DNA replication. The data on the stable fraction indicate that the DNA of strain 15
T-L-
, under our experimental conditions, may be organized into one duplex structure. Since colony-forming ability was used as the means of assay, it is possible to compare these experiments with those in which DNA segregation is examined on a structural basis.
Succinic Ester and Amide of Homoserine: Some Spontaneous and Enzymatic Reactions
Authors: Flavin Martin , Delavier-Klutchko Colette , Slaughter Clarence
Published: October 2006

O
-Succinylhomoserine and
N
-succinylhomoserine have been synthesized. The first is rapidly transformed into the second by alkali. In acid, the second undergoes ring closure to the lactone, rather than the reverse acyl transfer. Neither supports the growth of methionine auxotrophs of
Neurospora
or
Salmonella
. However, bacterial extracts rapidly catalyze formation of a compound, chromatographically identical with cystathionine, from cysteine and
O
-succinylhomoserine. In the absence of cysteine the
O
-succinylhomoserine is converted to α-ketobutyrate. Both these reactions are absent from the same
Salmonella
mutant, and therefore are probably catalyzed by a single enzyme which is needed for methionine synthesis. Both reactions require pyridoxal phosphate.
N
-succinylhomoserine does not undergo either reaction.
Contraction-Band Formation in Barnacle Myofibrils
Authors: Baskin R. J. , Wiese G. M.
Published: October 2006

Contractions induced by adenosine triphosphate, in myofibrils isolated from the barnacle,
Balanus aquilia
, were observed with a phase microscope. The formation of contraction bands was well under way before the A-band came into contact with the Z-membrane. This is in disagreement with the hypothesis that contraction bands are formed when the A-band pushes against the Z-membrane.
Heat Adaptation and Ion Exchange in
Bacillus megaterium
Spores
Authors: Alderton Gordon , Thompson P. A. , Snell Neva
Published: October 2006

A new spore phenomenon is described in which induction of increased heat resistance occurs during the process of heating. In buffered environments the acid form of dormant mature bacterial spores shows a temperature dependent adaptation to heat which is correlated with the rate of uptake of Ca(OH)
2
by titration at constant
p
H in neutral salt solution.
Fluoroacetate Inhibition of Amino Acids during Photosynthesis of
Chlamydomonas reinhardti
Authors: Kates Joseph R. , Jones Raymond F.
Published: October 2006

Fluoroacetate inhibited respiration in
Chlamydomonas reinhardti
and greatly decreased the photosynthetic incorporation of C
14
O
2
into glutamate and aspartate. This suggests that the Krebs cycle is important in the light-mediated synthesis of glutamate and aspartate in this alga.
High-Pressure Metallic Indium Telluride: Preparation and Crystal Structure
Authors: Sclar C. B. , Carrison L. C. , Schwartz C. M.
Published: October 2006

The metallic high-pressure form of indium telluride may be prepared under high pressure at 150°C and retained at ambient conditions without low-temperature quenching. It has the NaCl (type B1) structure with a cell edge of 6.160 ± .005 Å and a calculated density of 6.887 g/cm
3
. The density increase relative to the low-pressure polymorph is 15.6 percent.
Microsporum nanum
: First Recorded Isolation from Animals in the United States
Authors: Bubash George R. , Ginther Oliver J. , Ajello Libero
Published: October 2006

The first cases in the United States of swine infections caused by the fungus
Microsporum nanum
are reported. The infections occurred in a herd of Yorkshire swine in Pennsylvania. The dermatophyte, which readily produced experimental infections, was identified by isolation and studies in pure cultures.
Fossilized Stomach Contents of a Sauropod Dinosaur
Authors: Stokes William Lee
Published: October 2006

A mass of petrified plant and bone fragments found in the late Jurassic Morrison formation of southwestern Emery County, Utah, appears to be the stomach contents of a sauropod dinosaur, skeletal remains of which were associated with it. The sauropods may have been more or less omnivorous.
Radioautographic Evidence for the Incorporation of Leucine-Carbon-14 into the Mitotic Apparatus
Authors: Stafford D. W. , Iverson R. M.
Published: October 2006

Mitotic apparatus isolated at metaphase from sea urchin eggs, and placed in sea water containing leucine-carbon-14 after fertilization, has been shown by radioautographs to have taken up carbon-14 in such a way that it is not removable by repeated washing, by "chasing" with leucine-carbon-12, or by treatment with hot trichloroacetic acid.
Toxic Residues in Soil 9 Years after Treatment with Aldrin and Heptachlor
Authors: Wilkinson A. T. S. , Finlayson D. G. , Morley H. V.
Published: October 2006

In silt loam soil heavily infested with European wireworm, a single treatment with aldrin or heptachlor prevented reinfestation for 9 years, even when the soil was under continuous cultivation. Toxic residues were determined by bioassay with
Drosophila melanogaster
Meig. By gas-liquid chromatographic analysis, the residues were found to be mainly dieldrin and heptachlor epoxide.
Mutarotase Inhibition by 1-Deoxyglucose
Authors: Keston Albert S.
Published: October 2006

The Michaelis-Menten constant for glucose and the inhibitor constant of 1-deoxyglucose for the intestinal mutarotase, glucose, 1-deoxyglucose system are consistent with the properties of the glucose transport system of intestine. The alleged sharing of the intestinal glucose transport system by 1-deoxyglucose does not contradict the mutarotase theory.
Tritium-Hydrologic Research: Some Results of the U.S. Geological Survey Research Program
Authors: Carlston Charles W.
Published: October 2006

In general tritium is of limited usefulness as a tool in hydrologic studies because the tritium content of ground water, as a result of radioactive decay, becomes too low to be detectable after about 50 years. Nevertheless, a unique study was made of the hydrologic cycle of small stream basins in Wisconsin and New Jersey on the basis of measurements relative to the peak of tritium fallout in the spring of 1958. The continental and the coastal basins received approximately the same tritium fallout. Approximately 30 percent went into ground-water storage, the remainder being exported as runoff and evapotranspiration. The mean residence time for ground-water recharge for the two basins was 45 and 30 days, respectively.
Asynchronous Synthesis of RNA in Nucleoli of Root Meristem
Authors: Bal Arya K. , Gross Paul R.
Published: October 2006

During pulse incubations of onion roots with RNA precursors, incorporation into meristematic nucleoli is asynchronous for some, but not for all, cells. After a 30-minute labeling period, the "zero-class" is as large as 25 percent, and the asynchrony is intracellular rather than cellular. This suggests an individual specificity of nucleolar function in a population of differentiating cells.
Histocompatibility and Immunologic Competence in Renal Homotransplantation
Authors: Rubin Albert L. , Stenzel Kurt H. , Hirschhorn Kurt , Bach Fritz
Published: October 2006

Cultures of peripheral lymphocytes may be used to assay histocompatibility. The lymphocytes from potential kidney recipients are cultured with those from potential donors and the percentage of large cells and mitoses stimulated is determined. The immunologic competence of cultured lymphocytes from recipients receiving immunosuppressive therapy is evaluated by determining their responsiveness to phytohemagglutinin. Suppression of response appears to be correlated with the absence of clinical signs of graft rejection.
Electrophoretic and Immunological Studies of Squid Axoplasm Proteins
Authors: Huneeus-Cox Francis
Published: October 2006

By disc electrophoresis of the axoplasm of
Dosidicus gigas
, 14 protein bands have been resolved. Antibodies to the intra-axonal proteins and to squid blood proteins were produced in rabbits. By Ouchterlony's technique, six antigenic components can be demonstrated in axoplasm; the combined use of disc electrophoresis and immune diffusion in agar resolves seven antigenic components in axoplasm; none of these components is detectable in squid blood.
Electroencephalographic Desynchronization in Irradiated Rats with Transected Spinal Cords
Authors: Cooper G. P. , Kimeldorf D. J.
Published: October 2006

Rats with transected spinal cords showed electroencephalographic desynchronization and exhibited behavioral arousal in response to x-irradiation of the whole body or the head only, at dose rates between 0.5 and 1.5 roentgens per second. Neither arousal nor desynchronization occurred when only the body of the animal was exposed. Results indicate that neither the circulatory system nor the vagi are essential to the arousal reaction to x-irradiation.
Humoral Thymic Factor in Mice: Further Evidence
Authors: Law L. W. , Trainin N. , Levey R. H. , Barth W. F.
Published: October 2006

Mice of the C3H and DBA strains thymectomized at birth showed a consistent and striking suppression of antibody production (hemolysin response) to sheep erythrocytes. When cell-tight Millipore diffusion chambers containing syngeneic thymic tissue were implanted intraperitoneally, the capacity of these neonatally thymectomized mice to respond to this antigen was restored. The pattern of response and the mean titer were similar to the pattern and mean titer observed in neonatally thymectomized mice bearing subcutaneous grafts of syngeneic thymic tissue. These data are consistent with the concept that thymic tissue within the chamber produced a specific diffusible factor that enabled the thymectomized animal to establish immunologic competence.
Drug Administration to Neonatal Rats: Effects on Later Emotionality and Learning
Authors: Young Richard David
Published: October 2006

The effects of extra stimulation during postnatal days 2 to 4 in rats are mitigated by the injection of either norepinephrine or chlorpromazine prior to the stimulation. Behavioral changes in locomotion and defecation occurred in the open field, and there were changes in speed and accuracy of learning a simple maze problem.
Following and Imprinting: Effects of Light and Social Experience
Authors: Polt James M. , Hess Eckhard H.
Published: October 2006

Ninety-six Vantress broiler chicks were used in two studies of the effects of light and social experience on the "following" response. In addition, the animals used in one study were later tested to determine the amount of imprinting during following. The difference between the behavior of these animals and animals maintained in isolation and in darkness prior to exposure to a model, indicate that variability in treatment can influence the following behavior, and that following in itself cannot be equated with imprinting.
Early Arousal and Imprinting in Chicks
Authors: Thompson William R. , Dubanoski Richard A.
Published: October 2006

Arousal outside the test situation and prior to response acquisition can affect strength of imprinting, if such treatment occurs early enough in life. Young chicks handled in darkness either at 5 or 9 hours of age and exposed to a moving surrogate a number of hours later were compared with nonhandled controls by means of following tests given at 30 and 54 hours of age. Handling at 5 hours resulted in a significant increment in the later following response. Handling at 9 hours produced no effect.
Differences in the Amino Acid Composition of a Third Rabbit Antibody
Authors: Koshland Marian E. , Englberger Frieda M. , Shapanka Roslyn
Published: October 2006

Antibody directed against a neutral hapten,
p
-amino-β-phenyl lactoside, has been purified, and its amino acid composition has been determined. When the results were compared with the previous analyses of two rabbit antibodies, small but significant differences were found. The demonstration of a third unique antibody composition supports the hypothesis that the amino acid differences are related to specificity rather than to the heterogeneity of γ-globulin.
Brucella
-Agglutinating Antibodies: Relation of Mercaptoethanol Stability to Complement Fixation
Authors: Anderson R. K. , Jenness Robert , Brumfield Helene P. , Gough Patricia
Published: October 2006

Brucella
-agglutinating antibodies from selected bovine blood serums and milk samples did not fix complement, and after treatment with 2-mercaptoethanol they lost agglutinating power. After infection of calves with
Brucella abortus
, strain 19, agglutinins for
Brucella
that were inactivated by mercaptoethanol appeared earlier than those stable to mercaptoethanol. Under the conditions of these experiments, the appearance and development of complement-fixing capacity coincided closely with the mercaptoethanol stability of the agglutinins for
Brucella
.
Daily Rhythm in the Susceptibility of an Insect to a Toxic Agent
Authors: Cole Charles L. , Adkisson Perry L.
Published: October 2006

Adult boll weevils exhibited a daily rhythm in their susceptibility to standardized doses of the insecticide, methyl parathion. The mortality produced by the insecticide was intimately related to the time of day at which the toxicant was applied. The rhythm appeared to be photoperiodically entrained and, regardless of the length of day or "clock time-of-day of treatment," a period of greatest resistance always occurred at dawn and recurred at 6-hour intervals throughout the 24-hour cycle. The greatest difference in response occurred in a photoperiod having 10 hours of light per 24-hour cycle. Here, the same dose of methyl parathion killed approximately 10 percent of the weevils treated at dawn but almost 90 percent of those treated only 3 hours later.
Hydrocarbons of Biological Origin from a One-Billion-Year-Old Sediment
Authors: Eglinton Geoffrey , Scott P. M. , Belsky Ted , Burlingame A. L. , Calvin Melvin
Published: October 2006

The isoprenoid hydrocarbons, phytane (C
20
H
42
) and pristane (C
19
H
40
), are present in the oil seeping from the Precambrian Nonesuch formation at the White Pine Mine, Michigan. Gas-liquid chromatography and mass spectrometry provide the isolation and identification procedures.
Amino Acids: Incorporation into α- and β-Chains of Hemoglobin by Normal and Thalassemic Reticulocytes
Authors: Heywood J. David , Karon Myron , Weissman Sherman
Published: October 2006

After incubation of reticulocytes with radioactive amino acid, the specific activity of the β-chain of globin from the blood of patients with thalassemia was consistently lower than that of the α-chain. In subjects without this disorder, the specific activity of the β-chain was always equal to or higher than that of the α-chain.
Thermodynamic Equilibria in Prebiological Atmospheres
Authors: Dayhoff M. O. , Lippincott E. R. , Eck R. V.
Published: October 2006

The concentrations of a large number of compounds of biological interest which would be present in the atmosphere at thermodynamic equilibrium were computed under many combinations of temperature, pressure, and elemental composition. These computations revealed a possible mechanism for the abiological formation of asphaltic tar and an oxidative threshold at which all but the simplest compounds disappear.
Phytadienes in Zooplankton
Authors: Blumer Max , Thomas David W.
Published: October 2006

Four isomeric phytadienes have been isolated from mixed zooplankton of the Gulf of Maine. The chemical structures suggest that the mixture is derived by dehydration of phytol (presumably by acid catlysis), which is present in the diet of the zooplankton.
Bursa of Fabricius in Chickens: Possible Humoral Factor
Authors: St. Pierre Ronald L. , Ackerman G. Adolph
Published: October 2006

Chicks bursectomized by testosterone injection on the 5th day of incubation showed a marked inability to produce antibodies to
Salmonella typhimurium
. When portions of the bursa of Fabricius were enclosed in cell-impermeable Millipore diffusion chambers and implanted subcutaneously or intraperitoneally, the antibody-producing capacity of these animals was restored. Evidence strongly suggests that the bursa of Fabricius elaborates a noncellular agent capable of restoring immunologic reactivity in bursectomized chicks.
Optical Activity in the Orgueil Meteorite
Authors: Hayatsu Ryoichi
Published: October 2006

Nagy's report of an optical rotation of -0.023° to -0.084° in the Orgueil meteorite has not been confirmed. The highest rotation found in several fatty-acid and hydrocarbon fractions isolated from the meteorite was -0.002°, less than that of optically inactive controls. The "rotations" observed by Nagy may have been caused by scattered depolarized light from colloidal particles, reduced instrument sensitivity due to low transmittance of the solutions, or a combination of both.
Vacuolar Chitinases of Tobacco: a New Class of Hydroxyproline-Containing Proteins
Authors: Sticher Liliane , Hofsteenge Jan , Milani Alfred , Neuhaus Jean-Marc , Meins Frederick
Published: October 2006

The fungicidal type I chitinases contribute to the defense response of plants against pathogens. Two tobacco chitinases represent a different class of hydroxyproline-containing proteins. Hydroxyproline-rich proteins are predominantly extracellular, structural glycoproteins that lack enzymatic activity and contain many hydroxyproline residues. In contrast, type I chitinases are vacuolar enzymes. They are not glycosylated and contain a small number of hydroxyproline residues restricted to a single, short peptide sequence.
Dulcin and Saccharin Taste in Squirrel Monkeys, Rats, and Men
Authors: Fisher G. L. , Pfaffmann Carl , Brown Elliott
Published: October 2006

In a taste-preference comparison of sweetening agents, men reacted positively to two nonnutritive sweeteners, dulcin and sodium saccharin; rats preferred only saccharin and squirrel monkeys, only dulcin.
Differential-Approach Tendencies Produced by Injection of RNA from Trained Rats
Authors: Jacobson Allan L. , Babich Frank R. , Bubash Suzanne , Jacobson Ann
Published: October 2006

Two groups of rats were trained in a Skinner box to approach the food cup when a discriminative stimulus (click or blinking light) was presented. Ribonucleic acid was extracted from the brains of these two groups of rats and injected into two groups of untrained rats. The untrained two groups then manifested a significant tendency (as compared with one another) to react differently to the two stimuli. On the average, the response appeared to be specific to the stimulus employed during training.
Immunoelectrophoresis Reveals Collagen Solubility in Human Serum
Authors: Frey J. , Hoa Nguon , Gras J. , Henry J. C. , Gudefin Y.
Published: October 2006

A fraction of human-serum proteins which contains hydroxyproline migrates, on electrophoresis, with the α
2
-β-globulins. Immunoelectrophoresis with rabbit antiserum to soluble human collagen reveals an immunologically collagen-like protein in the human serum.
Gastric Secretion: Mechanism for Production of Hydrogen Ions
Authors: Gregor Harry P. , Berkowitz Jesse M.
Published: October 2006

The passage of a direct electric current across a fixed-charge membrane interposed between neutral electrolyte solutions can give rise to the production of hydrogen and hydroxide ions at the solution-membrane boundary in equivalent amounts, each of which can approach and equal the number of faradays passed. At this unique boundary, the electric field can inhibit the rate of recombination of hydrogen and hydroxide ions strongly enough to increase the dissociation constant of water and other weak electrolytes by several orders of magnitude. These observations lead to a model of the gastric secretory process wherein the gastric potential, primarily due to the activity of a chloride-ion pump, is applied across an adjacent ion-selective membrane also present in the mucosa. The dissociating weak electrolyte can be water, to produce hydrogen ions in the stomach and hydroxide ions which combine with carbon dioxide in the blood, or it can be carbonic acid to produce bicarbonate directly.
Alternative Forms of Triosephosphate Dehydrogenase in
Chromatium
Authors: Hudock G. A. , Mellin D. B. , Fuller R. C.
Published: October 2006

Triosephosphate dehydrogenase was purified extensively from the obligately phototrophic bacterium
Chromatium
. Enzyme prepared from photolithotrophically grown cells differed in several properties from enzyme prepared from photoorganotrophically grown cells. Either form of the enzyme could be transformed in vitro to the other by mild oxidation or reduction, which effected both Michaelis constants and reactive -SH contents of the proteins.
Protein Synthesis in Enucleated Eggs of
Rana pipiens
Authors: Smith L. Dennis , Ecker R. E.
Published: October 2006

Tritiated leucine of high specific activity was injected into enucleated
Rana pipiens
eggs. After 6 hours, there was significant, incorporation of the label into protein. The amount of incorporation in these eggs was as great as that in fertilized, normally developing eggs.