bluuebunny/crossref_metadata_2025 huggingface dataset:
Gangliosides and Other Lipids of the Growth Cone Membrane
Authors: Sbaschnig‐Agler Michele , Pfenninger Karl H. , Ledeen Robert W.
Published: October 2006

Growth cone membranes, derived from growth cone particles isolated from 16‐ to 18‐day‐old fetal rat brain, were found to be rich in overall lipid content with a lipid‐to‐protein ratio of 3.5. The phospholipid‐to‐cholesterol ratio indicated considerably less cholesterol than plasma membranes from mature neurons. All major classes of phospholipid were present in the usual proportions except sphingomyelin, which could not be detected. Gangliosides expressed in relation to protein were present at somewhat higher levels compared to previously reported values for synaptic plasma membranes (73 versus 44 μg/mg protein), but when related to phospholipid their level was well below that of the latter (26 versus 62 μg/mg phospholipid). The ganglioside pattern was generally similar to that of mature synaptic membranes except for the presence of relatively more GD3 and less GD1a, a phenomenon also observed in whole fetal brain of the same age. Several neutral glycosphingolipids were detected, glucosylceramide being the major one of this group. Their total level in growth cone membranes was roughly comparable to that of gangliosides, but unlike the latter their concentration in whole brain decreased with development. For comparison we analyzed the ganglioside composition of mixed membrane fractions from the same fetal brains and found no significant differences between these and growth cone membranes, suggesting that these glycoconjugates are not localized specifically in the growth cones. Neutral glycosphingolipids, on the other hand, appeared somewhat more concentrated in growth cones than in the mixed membranes.
Maitotoxin‐Evoked γ‐Aminobutyric Acid Release Is Due Not Only to the Opening of Calcium Channels
Authors: Pin Jean‐Philippe , Yasumoto Takeshi , Bockaert Joël
Published: October 2006

Abstract: The effects of maitotoxin (MTX) on endogenous amino acid release were tested on highly purified striatal neurons differentiated in primary culture. MTX induced a large and concentration‐dependent release of γ‐aminobutyric acid (GABA). This effect was abolished when experiments were performed in the absence of external Ca2+, and restored when Ca2+ ions were added after removing the MTX‐containing Ca2+‐free solution. MTX‐induced amino acid release was not affected by 1 μM nifedipine and only slightly inhibited by 1 mM Co2+. MTX also induced a massive accumulation of 45Ca2+ in the neurons which, in contrast to the MTX‐evoked GABA release, was totally blocked in the presence of 1 mM Co2+. Whereas 500 nM tetrodotoxin was without significant effect, MTX‐evoked GABA release was dependent on the presence of external Na+ and sensitive to nipecotic acid, a GABA uptake inhibitor. It is concluded that, on striatal neurons, MTX induced Na+ influx only in the presence of external Ca2+. The increase in cytoplasmic Na+ ions then triggers the release of GABA.
Effect of Organic and Inorganic Calcium Channel Blockers on γ‐Amino‐n‐Butyiic Acid Release Induced by Monensin and Veratrine in the Absence of External Calcium
Authors: Sitges María
Published: October 2006

Abstract: The effects of two organic Ca2+ antagonists (verapamil and nitrendipine) and of two inorganic Ca2+ channel blockers (Co2+ and ruthenium red) on the Na+‐dependent release of γ‐amino‐n‐butyric acid (GABA) triggered by veratrine and monensin in the absence of external Ca2+ were studied in mouse brain synaptosomes. Ca2+‐independent release of GABA stimulated by the Na+ channel activator veratrine was inhibited with micromolar concentrations of verapamil and nitrendipine. In contrast, GABA release induced by the Na+ ionophore monensin was insensitive to the organic Ca2+ antagonists. Verapamil also failed to modify A23187‐stimulated release of GABA in the presence of Ca2+ but inhibited high K+‐induced release of the transmitter. Co2+ partially diminished veratrine‐induced release but did not change monensin‐induced release. Releasing responses to monensin and veratrine were insensitive to ruthenium red, which inhibited the Ca2+‐dependent component of GABA release evoked by high K+ depolarization. These data demonstrate that the mechanism of inducing GABA release is different for veratrine and monensin, as evidenced by their differing sensitivities to inhibition by Ca2+ channel antagonists and organic Ca2+ blockers. It is concluded that voltage‐sensitive Ca2+ channels of the presynaptic membrane are not involved in the inhibitory action of Ca2+ antagonists on the Na+‐de‐pendent, Ca2+‐independent mechanism of GABA release.
Uptake of Exogenous PhosphatidyJserine by Human Neuroblastoma Cells Stimulates the Incorporation of [methyl‐l4C]Cholne into Phosphatidylcholine
Authors: Slack B. E. , Liscovitch M. , Blusztajn J. K. , Wurtman R. J.
Published: October 2006

Abstract: The phosphatidylserine (PtdSer) content of human cholinergic neuroblastoma (LA‐N‐2) cells was manipulated by exposing the cells to exogenous PtdSer, and the effects on phospholipid content, membrane composition, and incorporation of choline into phosphatidylcholine (PtdCho) were investigated. The presence of liposomes containing PtdSer (10‐130 μM) in the medium caused time‐ and concentration‐dependent increases in the PtdSer content of the cells, and smaller and slower increases in the contents of other membrane phospholipids. The PtdSer levels in plasma membrane and mitochondrial fractions prepared by discontinuous sucrose density gradient centrifugation increased by 50 and 100%, respectively, above those in control cells after 24 h of exposure to PtdSer (130 μM). PtdSer caused a concomitant, concentration‐dependent increase of up to twofold in the incorporation of [methyl‐14C]choline chloride into PtdCho at a choline concentration (8.5 μM) compatible with activation of the CDP‐choline pathway, suggesting that the levels of PtdSer in membranes may serve as a stimulus to regulate overall membrane composition. PtdSer caused a mean increase of 41% in PtdCho labeling, but the phorbol ester, phorbol 12‐myristate 13‐acetate (PMA), which stimulates PtdCho synthesis in a number of cell lines, increased [4C]PtdCho levels by only 14% in LA‐N‐2 cells, at a concentration (100 nM) which caused complete translocation of the calcium‐ and phospholipid‐dependent enzyme protein kinase C to the membrane. The translocation was inhibited by prior exposure of the cells to PtdSer. Treatment with PMA for 24 h diminished protein kinase C activity by 80%, but increased the labeling of PtdCho in both untreated and PtdSer‐treated cells. These data suggest that uptake of PtdSer by LA‐N‐2 cells alters both the phospholipid composition of the membrane and synthesis of the major membrane phospholipid PtdCho; the latter effect does not involve activation of protein kinase C.
Mesencephalic Dopamine Neurons Become Less Sensitive to 1 ‐Methyl‐4‐Phenyl‐l,2,3,6‐Tetrahydropyridine Toxicity During Development In Vitro
Authors: Danias Peter , Nicklas William J. , Ofori Senyo , Shen Julia , Mytilineou Catherine
Published: October 2006

Abstract: The in vitro development of monoamine oxidase (MAO) activity and [3H]dopamine (DA) uptake capacity of dissociated cell cultures from rat embryo mesencephalon were correlated with the potency of l‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) and l‐methyl‐4‐phenylpyridine (MPP+) neurotoxicity. Specific activities of both MAO‐A and MAO‐B increased during in vitro development of the cultures, with MAO‐B activity increasing 20‐fold between the first and fourth week. Similarly, [3H]DA accumulation increased 2.6‐fold between the first and third week in vitro, when it reached a plateau. Unexpectedly, the toxicities of MPTP and MPP+were substantially decreased in the older cultures. Exposure to MPTP reduced [3H]DA accumulation per culture by 77% in 1‐week‐old cultures and by 36% in 4‐week‐old cultures. Similarly, damage caused by MPP+ was reduced from 84% of control in the first week to 34% of control in the fourth week. The attenuation of neurotoxicity was not due to an increase in storage of MPP+ in the synaptic vesicles of DA neurons, nor to a change in the distribution of MPP+ between dopaminergic and other cellular components of the cultures. The damage to DA neurons caused by the mitochondrial toxin, rotenone, also showed a similar reduction in the older cultures. These observations coupled with an increase in lactate formation and glucose consumption during the in vitro development of the cultures suggest a shift toward increased glycolysis and decreased dependence on aerobic metabolism. This would render the cells more resistant to the inhibition of mitochondrial function by MPP+.
Polyclonal Antibodies to the Glycine Receptor Antagonist Strychnine
Authors: Phelan P. P. , Fry J. P. , Martin I. L. , Johnston G. A. R.
Published: October 2006

Abstract: Polyclonal antibodies have been raised in rabbits against the glycine receptor antagonist strychnine, coupled through a 2‐amino substituent to the antigenic protein keyhole limpet haemocyanin. Strychnine binding of the predominantly immunoglobulin G (IgG) class of antibodies was measured by incubation with [3H]strychnine, followed by adsorption of IgG onto Staphylococcus aureus cells and filtration through glass‐fibre filters under vacuum. Only strychnine and structurally related alkaloids or derivatives were able to inhibit [3H]strychnine binding to the IgG. A significant rank correlation was found between the potencies of these compounds to inhibit [3H]strychnine binding to the antibodies and to the glycine receptor in mouse spinal cord membranes. In contrast, preincubation of strychnine antibodies with a variety of ligands at other neurotransmitter, drug, or hormone receptors in the CNS (at 10−4M) failed to inhibit binding significantly. The failure of glycine to inhibit strychnine antibody binding is consistent with previous suggestions that the recognition sites for this amino acid on the CNS receptor may be conformationally distinct from those for the antagonist alkaloid. Strychnine antibodies may now help in the identification and purification of possible endogenous ligands at this alkaloid binding site in the CNS.
Regional Distribution of Neuropeptide Y and Its Receptor in the Porcine Central Nervous System
Authors: Busch‐Sørensen M. , Sheikh S. P. , O'Hare M. , Tortora O. , Schwartz T. W. , Gammeltoft S.
Published: October 2006

Abstract: The regional distribution of neuropeptide Y (NPY) immunoreactivity and receptor binding was studied in the porcine CNS. The highest amounts of immunoreactive NPY were found in the hypothalamus, septum pellucidum, gyrus cinguli, cortex frontalis, parietalis, and piriformis, corpus amygdaloideum, and bulbus olfactorius (200–1,000 pmol/g wet weight). In the cortex temporalis and occipitalis, striatum, hippocampus, tractus olfactorius, corpus mamillare, thalamus, and globus pallidus, the NPY content was 50–200 pmol/g wet weight, whereas the striatum, colliculi, substantia nigra, cerebellum, pons, medulla oblongata, and medulla spinalis contained <50 pmol/g wet weight. The receptor binding of NPY was highest in the hippocampus, corpus fornicis, corpus amygdaloideum, nucleus accumbens, and neurohypophysis, with a range of 1.0–5.87 pmol/mg of protein. Intermediate binding (0.5–1.0 pmol/mg of protein) was found in the septum pellucidum, columna fornicis, corpus mamillare, cortex piriformis, gyrus cinguli, striatum, substantia grisea centralis, substantia nigra, and cerebellum. In the corpus callosum, basal ganglia, corpus pineale, colliculi, corpus geniculatum mediale, nucleus ruber, pons, medulla oblongata, and medulla spinalis, receptor binding of NPY was detectable but <0.5 pmol/mg of protein. No binding was observed in the bulbus and tractus olfactorius and adenohypophysis. In conclusion, immunoreactive NPY and its receptors are widespread in the porcine CNS, with predominant location in the limbic system, olfactory system, hypothalamoneurohypophysial tract, corpus striatum, and cerebral cortex.
Role of Intracellular pH in the Axolemma‐ and Myelin‐Induced Proliferation of Schwann Cells
Authors: Saunders Royal D. , Brandon Yvonne W. , DeVries George H.
Published: October 2006

Abstract: In order to provide additional information on the biochemical events that interact to cause Schwann cells to proliferate, we have monitored the intracellular pH of Schwann cells that have been stimulated to divide with myelin‐enriched fractions (MEF) or axolemma‐enriched fractions (AEF). The intracellular pH of Schwann cells was monitored using 2′,7′‐bis(carboxymethyl)‐5(6)‐carboxyfluorescein (BCECF), which displays an increase in fluorescence upon alkalinization. Both AEF and MEF caused dose‐dependent increases in the intracellular fluorescence of the Schwann cell cultures. At their maximum doses, AEF and MEF stimulation resulted in a 260 and 300% increase in intracellular fluorescence, respectively. The increase in intracellular fluorescence was abolished when cells were stimulated in Na+‐free media, suggesting a role for the Na+/H+ exchanger. Mitotic stimulation required integrity of the Na+/H+ exchanger, as inhibition of the Na+/H+ exchanger for periods up to 1 h after addition of mitogen caused a significant inhibition of subsequent mitosis. Phorbol esters, which can potentiate AEF‐and MEF‐induced Schwann cell proliferation, increased intracellular fluorescence fivefold, an effect which was also dependent upon the presence of Na+ in the culture media. The specificity of the increase in intracellular pH for AEF and MEF was tested by incubating Schwann cells with liver microsomes and a biologically inactive phorbol alcohol, neither of which is significantly mitogenic for Schwann cells. Neither liver microsomes nor phorbol alcohol had a significant effect on intracellular pH. The implications of the increase in intracellular pH in Schwann cells with respect to inositol phospholipid metabolism, protein kinase C activation, and cellular proliferation are discussed.
Repetitive Action Potentials in Isolated Nerve Terminals in the Presence of 4‐Aminopyridine: Effects on Cytosolic Free Ca2+ and Glutamate Release
Authors: Tibbs G. R. , Barrie A. P. , Van Mieghem F. J. E. , McMahon H. T. , Nicholls D. G.
Published: October 2006

Abstract: The mechanisms by which an elevated KCl level and the K+‐channel inhibitor 4‐aminopyridine induce release of transmitter glutamate from guinea‐pig cerebral cortical synaptosomes are contrasted. KC1 at 30 mM caused an initial spike in the cytosolic free Ca2+ concentration ([Ca2+]c), followed by a partial recovery to a plateau 112 ± 13 n M above the polarized control. The Ca2+‐dependent release of endogenous glutamate, determined by continuous fluorimetry, was largely complete by 3 min, by which time 1.70 ± 0.35 nmol/ mg was released. [Ca2+]c elevation and glutamate release were both insensitive to tetrodotoxin. KCl‐induced elevation in [Ca2+]c could be observed in both low‐Na+ medium and in the presence of low concentrations of veratridine. 4‐Aminopyridine at 1 mM increased [Ca2+]c by 143 ± 18 nM to a plateau similar to that following 30 mM KCl. The initial rate of increase in [Ca2+]c following 4‐aminopyridine administration was slower than that following 30 mM KCl. and a transient spike was less apparent. Consistent with this, the 4‐aminopyridine‐induced net uptake of 45Ca2+ is much lower than that following an elevated KCl level. 4‐Aminopyridine induced the Ca2+‐dependent release of glutamate, although with somewhat slower kinetics than that for KCl. The measured release was 0.81 nmol of glutamate/mg in the first 3 min of 4‐aminopyridine action. In contrast to KCl, glutamate release and the increase in [Ca2+]c with 4‐aminopyridine were almost entirely blocked by tetrodotoxin, a result indicating repetitive firing of Na+ channels. Basal [Ca2+]c and glutamate release from polarized synaptosomes were also significantly lowered by tetrodotoxin. Addition of 30 mM KCl to 4‐ami‐nopyridine‐pretreated synaptosomes caused a large transient spike in [Ca2+]c and further release of glutamate. 4‐Aminopyridine failed to increase [Ca2+]c in low‐Na+ media or after addition of low concentrations of veratridine. It is proposed that an unstable membrane potential in the presence of 4‐aminopyridine is amplified by repetitive firing of Na+ channels and that this leads to random opening of transient Ca2+ channels in the synaptosomal population. In contrast, KCl would induce a synchronous activation of transient Ca2+ channels followed by a plateau of low residual channel conductance. By mimicking repetitive stimulation in vivo, 4‐aminopyridine may more closely model physiological excitation than does an elevated KCl level. Our results are difficult to reconcile with a major role for Na+/Ca2+ exchange in the elevation of [Ca2+]c and contradict proposals that 4‐aminopyridine induces release of transmitter from isolated nerve terminals by a mechanism not linked to Na+‐channel firing orCa2+ entry
Mitochondrial and Peroxisomal β‐Oxidation of Stearic and Lignoceric Acids by Rat Brain
Authors: Singh Harmeet , Usher Sylvia , Poulos Alf
Published: October 2006

Abstract: Crude subcellular fractions were prepared from adult rat brains by differential centrifugation of brain ho‐mogenates. Greater than 98% of the cellular mitochondrial marker enzyme activity sedimented in the heavy and light mitochondrial pellets, and <1% of the activity sedimented in microsomal pellets. Lysosomal marker enzyme activities mainly (71‐78% of cellular activity) sedimented in the heavy and light mitochondrial pellets. Significant amounts of the lysosomal marker enzyme activity also sedimented in the crude microsomal pellets (9‐13% of total) and high‐speed supernatants (14‐16% of total). The specific activities of microsomal and peroxisomal marker enzyme activities were highest in the crude microsomal pellets. Fractionation of the crude microsomal pellets on Nycodenz gradients resulted in the separation of the bulk of the remaining mitochondrial, lysosomal, and microsomal enzyme activities from peroxisomes. Fatty acyl‐CoA synthetase activities separated on Nycodenz gradients as two distinct peaks, and the minor peak of the activities was in the peroxisomal enriched fraction. Fatty acid β‐oxidation activities also separated as two distinct peaks, and the activities were highest in the peroxisomal enriched fractions. Mitochondria were purified from the heavy mitochondrial pellets by Percoll density gradients. Fatty acyl‐CoA synthetase and fatty acid β‐oxidation activities were present in both the purified mitochondrial and peroxisomal enriched fractions. Stearoyl‐CoA synthetase activities were severalfold greater compared to lignoceroyl‐CoA synthetase, and stearic acid β‐oxidation was severalfold greater compared to lignoceric acid β‐oxidation in purified mitochondrial and peroxisomal enriched fractions. The results presented demonstrate conclusively that, in contrast to rat liver and human skin fibroblasts, rat brain mitochondria contain lignoceroyl‐CoA synthetase, as well as lignoceric acid β‐oxidation activities
Pyruvate Dehydrogenase Interactions with Peripheral‐Type Benzodiazepine Receptors
Authors: Daval Jean‐Luc , Post Robert M. , Marangos Paul J.
Published: October 2006

Abstract: Although peripheral‐type benzodiazepine recognition sites have been demonstrated in the brain of various species, the precise identity and function of the peripheral benzodiazepine receptor have not been established yet. In light of the recent demonstration of the mitochondrial localization of this receptor and its potential role in intermediary metabolism, we investigated the relationship between the benzodiazepines and the enzyme pyruvate dehydrogenase (PDH), a component of the mitochondrial membrane. The results obtained in the present study demonstrate a specific interaction between PDH and the ligands for the peripheral‐type benzodiazepine receptor, which might account for their effects on cell growth and differentiation.
Modulation of Ganglioside Biosynthesis in Primary Cultured Neurons
Authors: van Echten Gerhild , Sandhoff Konrad
Published: October 2006

Abstract: Murine cerebellar cells were pulse labeled with [14C]galactose, and the incorporation of radioactivity into gangliosides and neutral glycosphingolipids was examined under different experimental conditions. In the presence of drugs affecting intracellular membrane flow, as well as at 15°C, labeled GlcCer was found to accumulate in the cells, whereas the labeling of higher glycosphingolipids and gangliosides was reduced. Monensin and modulators of the cytoskeleton effectively blocked biosynthesis of the complex gangliosides GM1, GD1a, GD1b, GT1b, and GQ1b, whereas incorporation of radioactivity into neutral glycosphingolipids, such as glucosylceramide and lactosylceramide, as well as GM3, GM2, and GD3 was either increased or unaltered. As monensin has been reported to interfere with the flow of molecules from the cis to the trans stacks of the Golgi apparatus, this result highlights at least one subcompartmentalization of ganglioside biosynthesis within the Golgi system. Inhibitors of energy metabolism affected, predominantly, the biosynthesis of the b‐series gangliosides, whereas a reduced temperature (15°C) more effectively blocked incorporation of radiolabel into the a‐series gangliosides, a result suggesting the importance of GM3, as the principal branching point, for the regulation of ganglioside biosynthesis.
Uptake of Glycine into Synaptic Vesicles Isolated from Rat Spinal Cord
Authors: Christensen Hege , Fykse Else M. , Fonnum Frode
Published: October 2006

Glycine was taken up by a synaptic vesicle fraction from spinal cord in a Mg‐ATP‐dependent manner. The accumulation of glycine was inhibited by carbonyl cyanide‐m‐chlorophenylhydrazone (CCCP) and nigericin, agents known to destroy the proton gradient across the vesicle membrane. Vesicular uptake of glycine was clearly different from synaptosomal uptake, with respect to both the affinity constant and the effect of Na+, ATP, CCCP, and temperature. Oligomycin and strychnine did not inhibit the vesicular uptake, showing that neither mitochondrial H+‐ATPase nor binding to strychnine‐sensitive glycine receptors was involved. It is suggested that the vesicular uptake of glycine is driven by a proton gradient generated by a Mg2+‐ATPase. A low concentration of Cl‐ had little effect on the uptake of glycine, whereas the uptake of glutamate in the same experiment was highly stimulated. High concentrations of γ‐amino‐n‐butyric acid and β‐alanine inhibited vesicular glycine uptake, but glutamate did not. Accumulation of glycine was found to be fourfold higher in a spinal cord synaptic vesicle fraction than in a vesicle fraction from cerebral cortex.
Splicing site mutations in dentin sialophosphoprotein causing dentinogenesis imperfecta type II
Authors: Holappa Heidi , Nieminen Pekka , Tolva Liisa , Lukinmaa Pirjo‐Liisa , Alaluusua Satu
Published: October 2006

Dentinogenesis imperfecta (DGI) type II (OMIM # 125490) is an inherited disorder affecting dentin. Defective dentin formation results in discolored teeth that are prone to attrition and fracture. To date, several mutations have been described in the dentin sialophosphoprotein (DSPP) gene, causing DGI types II and III and dentin dysplasia type II. DSPP encodes two proteins: dentin sialoprotein (DSP) and dentin phosphoprotein (DPP). Here, we describe a mutational analysis of DSPP in seven Finnish families with DGI type II. We report two mutations and five single nucleotide polymorphisms. In one family we found a mutation that has been described earlier in families with different ethnicity, while in six families we found a novel g.1194C>A (IVS2‐3) transversion. Bioinformatic analysis of known DSPP mutations suggests that DGI type II is usually caused by aberration of normal splicing.
Effect of Spinal Fluid from Patients with Myasthenia Gravis on the Synthesis of Acetylcholine in Vitro
Authors: Torda Clara , Wolff Harold G.
Published: October 2006

Human spinal fluid is a more favorable medium to further the synthesis of acetylcholine
in vitro
, using enzyme obtained from frog brain, than is serum. Also, since less acetylcholine was synthesized in the presence of spinal fluid from patients with myasthenia gravis than spinal fluid of control subjects, it is probable that at least some of the factors responsible for the decrease and increase of the synthesis of acetylcholine pass into the spinal fluid.
Telang Liver and Vitamin A Toxicity
Authors: Herbst Edward J. , Pavcek Paul L. , Elvehjem C. A.
Published: October 2006

(1) About 20 per cent. of fresh telang livers were toxic to weanling rats receiving the calcium supplemented livers as their sole dietary.

(2) The symptoms observed in rats were growth failure and multiple spontaneous fractures of the bones of the extremities.

(3) The toxicity of certain telang livers was due to their abnormally high stores of vitamin A. When these livers, supplemented only with calcium carbonate, were fed to weanling rats, the daily intake of vitamin A was in excess of the toxic dosage of 15,000 I.U. per day.

(4) Identical symptoms of toxicity were observed in weanling rats fed 20,000 I.U. of crystalline vitamin A per day in conjunction with a standard stock ration.
Post-War Geology
Authors: Willard Bradford
Published: October 2006

Believing as I do that geology in the immediate future will have a greater application, that with that application we shall see its expansion, I present the suggestions in this paper. They are based upon careful consideration, analyses, deductions from assembled views and opinions. Specialization will mean more and better geologists but also a greater graduate school population which must be fed from the undergraduate curriculum. There, and there particularly, is the basement complex on which to build. The greatest immediate need in geology is a broad, adequate undergraduate preparation, not so much in geology itself, but in a slightly appalling list of collateral "must" subjects. Once this foundation is attained, graduate work in its several fields will care for itself.
The Effect of Atropine Sulfate on the Course of Influenza Virus Infection
Authors: Wheeler A. H. , Nungester W. J.
Published: October 2006

It has been shown in mice that the administration of atropine sulfate intraperitoneally before the intranasal instillation of influenza A virus decreased the incidence and extent of infection of these animals.
Hypophysial Responses to Continuous and Intermittent Delivery of Hypothalamic Gonadotropin-Releasing Hormone
Authors: Belchetz P. E. , Plant T. M. , Nakai Y. , Keogh E. J. , Knobil E.
Published: October 2006

In rhesus monkeys with hypothalamic lesions that abolish gonadotropic hormone release by the pituitary gland, the constant infusion of exogenous gonadotropin-releasing hormone (GnRH) fails to restore sustained gonadotropin secretion. In marked contrast, intermittent administration of the synthetic decapeptide once per hour, the physiological frequency of gonadotropin release in the monkey, reestablishes pituitary gonadotropin secretion. This phenomenon is attributable to the pattern of GnRH delivery rather than to the amounts of this hormone to which the cells of the pituitary are exposed. Moreover, the initiation of continuous GnRH administration in animals with lesions and in which gonadotropin secretion is reestablished by intermittent GnRH replacement can result in a "desensitization" or "down regulation" of the processes responsible for gonadotropin release.
Relationship Between Pathogenicity and
p
H Tolerance of Microorganisms
Authors: Leise J. M. , James L. H.
Published: October 2006

An alkaline medium (Sabouraud's dextrose or maltose agar of pH 10.5) was found to be selective for dermatophytes in the presence of the rapidly growing saprophytic fungi and has been used to isolate dermatophytes from mixed cultures and leather. Virulent dysentery bacteria are able to grow in media of alkaline pH values, while non-virulent strains of the same microorganisms are inhibited completely or very greatly. It is strongly indicated that pathogenicity may be related to pH tolerance and it is suggested that this relationship may be explained by the presence of a trypsin-like enzyme or enzyme system, while a loss of pathogenicity is associated with a loss or weakening of this enzyme system.
Sedimentation of Poliomyelitis Virus by Centrifugation
Authors: Silverberg Rosalie J.
Published: October 2006

A technic is described whereby poliomyelitis virus may be sedimented by centrifugation for four hours at 18,000 r.p.m.

Virus has been recovered quantitatively in the sediment from a 20 per cent., but not a 1 per cent., saline suspension. The addition of 10 per cent. normal serum results in quantitative recovery from a 1 per cent. suspension.

Virus has been recovered by intracerebral inoculation from two of four human stools tested by the method described.
Scientific Apparatus and Laboratory Methods the Histochemical Localization of Adenosinetriphosphatase in Plant and Animal Tissues
Authors: Glick David , Fischer Erna E.
Published: October 2006

A method has been described for the histochemical localization of acid and alkaline ATPase in plant and animal tissues respectively. A hanging-drop technique has been developed that permits the use of a minimum of substrate,
i.e.
, one small drop for each tissue section. ATPase in wheat was demonstrated for the first time.
Further Studies on the Monkey Anti-Anemia Factor
Authors: Cooperman Jack M. , McCall Keith B. , Elvehjem C. A.
Published: October 2006

Fresh liver was found to be a more potent source of the monkey anti-anemia factor than whole liver powder. Beef and pork livers had equal potency. Lyophilized liver retained all the active principle of fresh liver.
Neuronal Plasticity in Primate Telencephalon: Anomalous Projections Induced by Prenatal Removal of Frontal Cortex
Authors: Goldman Patricia S.
Published: October 2006

When the dorsolateral prefrontal cortex in one hemisphere of a rhesus monkey is resected 6 weeks before birth and the fetus survives to postnatal ages, neurons of the corresponding cortex in the intact hemisphere issue a greatly expanded projection to the contralateral caudate nucleus in addition to a normal projection to the ipsilateral caudate. The enhancement of the crossed prefronto-caudate pathway after prenatal neurosurgery provides direct evidence for lesion-induced neuronal rearrangement in the primate telencephalon.
Interference With the Antibacterial Action of Streptomycin by Reducing Agents
Authors: Bondi Amedeo , Dietz Catherine C. , Spaulding Earle H.
Published: October 2006

The antibacterial activity of streptomycin in infusion agar plate cultures of
E. coli
and other bacteria is diminished by anaerobic incubation. The bacteriostatic activity of this antibiotic for
E. coli
is reduced in the presence of cysteine, sodium thioglycollate, stannous chloride, sodium bisulfite, sodium hydrosulfite, sodium formate, and sodium thiosulfate. Cysteine was the most active of the agents tested. Further investigation is necessary to determine the nature of this interference. It is possible that this phenomenon is related to the mode of action of streptomycin.
Carcinogenic Substances From Pituitary Glands of Cattle
Authors: Wachtel Henry K.
Published: October 2006

Lipid extracts from the pituitary gland of cattle were prepared which, when injected into a pure strain of white mice, caused development of malignant tumors in 26.8 per cent of the 67 animals injected, which corresponds with the numerical results obtained by investigators working with human liver extracts. Evidently the carcinogenic power of these lipid extracts is low. The tumors developed chiefly in organs at a distance from the site of injection, exhibiting various histological types including carcinoma as well as sarcoma. The tumors developed at an earlier date after injection of extracts from the anterior lobe as compared with those developing after injection of the posterior lobe extracts, the average period of time necessary for their development being 9.3 months for the anterior lobe extracts and 14 months for posterior lobe extracts.
The Effect of the Prepartum Diet of the Cow on the Vitamin A Reserves of Her Newborn Offspring
Authors: Wide G. H. , Caldwell M. J. , Hughes J. S.
Published: October 2006

Feeding vitamin A at the rate of a million U.S.P. units daily to individual dairy cows in the latter stages of gestation augmented significantly the vitamin A concentration in the blood and the livers of their newborn calves, but pasture grazing, providing an abundance of carotene in the prepartum diet of the dams, failed to effect an increase over that observed in calves from dams restricted to a standard winter ration. The explanation for these divergent results is obscure, but it is suggested that the placental membrane may be more permeable to the ester form of vitamin A than to the alcohol form. This high initial vitamin A reserve in the newborn calf should have practical value in the maintenance of its postnatal health.
Growth and Aging Problems in Agriculture
Authors: Brody Samuel
Published: October 2006

It appears that while the immediate objectives of the agriculturist differ from those of the academic biologist, the long-range needs for standards of growth and aging, for physiologically equivalent units of time and mass, and for knowledge of the influence and mechanisms of various internal and external factors on growth and related processes are the same for both. This suggests that these two groups of biologists should work together more closely.
Effect of Penicillin on Seed Germination
Authors: Smith Walton J.
Published: October 2006

The substances present in therapeutic penicillin which cause inhibition of germination and root growth are represented by the indole-3-acetic acid type of compound. Since this and phenylacetic acid were known to be present in the penicillin tested, it is concluded that they are responsible for the inhibition activity against seeds.

None of the crystalline penicillins tested appreciably retarded germination.
Atrophy of Ovaries Transplanted to the Spleen in Unilaterally Castrated Rats; Proliferative Changes Following Subsequent Removal of Intact Ovary
Authors: Biskind Gerson R. , Biskind Morton S.
Published: October 2006

An ovary placed in the spleen of an animal that has one normal ovary undergoes atrophy that starts as early as 24 days after transplantation. Severe atrophy is reached before 55 days, and subsequent changes are minor. The degree of atrophy is almost as intense as that noted in the hypophysectomized castrate animal with an ovarian transplant in the spleen. The transplanted ovary shows no evidence of any type of response to the hormonal influence that has stimulated the ovary that remained
in situ.
Removal of the normal ovary introduces the hormonal imbalance that was present in the original tumor animals. The atrophic ovarian parenchyma in the spleen in these, as well as in the hypophysectomized animals previously reported, retained its growth potentials and responded to the hormonal forces by assuming the changes that characterized the development of the luteoma. The action of the atrophic ovarian parenchyma is reminiscent of malignant cell deposits that may remain dormant or quiescent for long periods and then, for some unknown reason, suddenly undergo growth.
Recent Advances in Color Vision
Authors: Hartridge H.
Published: October 2006

Until a few years ago it was possible to account for nearly all the aspects of human color perception on the basis of the three-color theory, but such is no longer the case. This is largely due to improvements in the older methods of investigation and to the invention of new ones. Among the latter may be mentioned the microelectrode technique of Granit and the retinal direction effect of Stiles and Crawford. Modern requirements are met by a polychromatic theory, comprising 7 types of receptor, but there is no necessity for these to have such narrow spectral response curves as those exhibited by Granit's modulators. Modifications of the three- and four-color theories have been examined to see to what extent they can be made to fit in with experimental results. Particular notice has been taken of the possibility that there is polychromatism of the retinal receptors, but trichromatism of the nerve paths which connect these to the brain or even of the brain itself.

The conclusion arrived at is that there must be polychromatism throughout the entire visual mechanism for color perception if a complete account is to be given of all the known facts.
Sleep Cycle Oscillation: Reciprocal Discharge by Two Brainstem Neuronal Groups
Authors: Hobson J. Allan , McCarley Robert W. , Wyzinski Peter W.
Published: October 2006

During the sleep cycle in cats, neurons localized to the posterolateral pole of the nucleus locus coeruleus and the nucleus subcoeruleus undergo discharge rate changes that are the opposite of those of the pontine reticular giant cells. The inverse rate ratios and activity curves of these two interconnected populations are compatible with reciprocal interaction as a physiological basis of sleep cycle oscillation.
Haploidploidy and the Evolution of the Social Insect
Authors: Trivers Robert L. , Hare Hope
Published: October 2006

Hamilton was apparently the first to appreciate that the synthesis of Mendelian genetics with Darwin's theory of natural selection had profound implications for social theory. In particular, insofar as almost all social behavior is either selfish or altruistic (or has such effects), genetical reasoning suggests that an individual's social behavior should be adjusted to his or her degree of relatedness, r, to all individuals affected by the behavior. We call this theory kinship theory.

The social insects provide a critical test of Hamilton's kinship theory. When such theory is combined with the sex ratio theory of Fisher, a body of consistent predictions emerges regarding the haplodiploid Hymenoptera. The evolution of female workers helping their mother reproduce is more likely in the Hymenoptera than in diploid groups, provided that such workers lay some of the male-producing eggs or bias the ratio of investment toward reproductive females. Once eusocial colonies appear, certain biases by sex in these colonies are expected to evolve. In general, but especially in eusocial ants, the ratio of investment should be biased in favor of females, and in ants it is expected to equilibrate at 1 : 3 (male to female). We present evidence from 20 species that the ratio of investment in monogynous ants is, indeed, about 1 : 3, and we subject this discovery to a series of tests. As expected, the slave-making ants produce a ratio of investment of 1 : 1, polygynous ants produce many more males than expected on the basis of relative dry weight alone, solitary bees and wasps produce a ratio of investment near 1 : 1 (and no greater than 1 : 2), and the social bumblebees produce ratios of investment between 1 : 1 and 1 : 3. In addition, sex ratios in monogynous ants and in trapnested wasps are, as predicted by Fisher, inversely related to the relative cost in these species of producing a male instead of a female. Taken together, these data provide quantitative evidence in support of kinship theory, sex ratio theory, the assumption that the offspring is capable of acting counter to its parents' best interests, and the supposition that haplodiploidy has played a unique role in the evolution of the social insects.

Finally, we outline a theory for the evolution of worker-queen conflict, a theory which explains the queen's advantage in competition over male-producing workers and the workers' advantage regarding the ratio of investment. The theory uses the asymmetries of haplodiploidy to explain how the evolved outcome of parent-offspring conflict in the social Hymenoptera is expected to be a function of certain social and life history parameters.
Prostaglandins in Human Seminal Fluid: Two Novel Compounds
Authors: Jonsson Haldor T. , Middleditch Brian S. , Desiderio Dominic M.
Published: October 2006

Human seminal fluid frozen immediately after ejaculation contains two novel prostaglandins. These are present in larger quantities than the previously reported prostaglandins. They are characterized by gas chromatography and mass spectrometry as 19-hydroxyprostaglandins E
1
and E
2
. Most of the previously identified prostaglandins may be artifacts.
Far-Field Acoustic Response: Origins in the Cat
Authors: Buchwald Jennifer S. , Huang Chi-Ming
Published: October 2006

Short-latency evoked potentials recorded from the vertex of adult cats in response to click stimulation (the far-field acoustic response) were analyzed in a series of lesion experiments to determine the origins of each component. The resultant data indicate that the primary generator of potential 1 is the acoustic nerve; of potential 2, the cochlear nucleus; of potential 3, neurons of the superior olivary complex activated by projections crossing the midline; of potential 4, neurons of the ventral nucleus of the lateral lemniscus and preolivary region activated equally by crossed and uncrossed projections; and of potential 5, neurons of the inferior colliculus activated primarily by crossed projections.
Purposive Behavior as a Basis for Objective Communication Between Chimpanzees
Authors: Menzel Emil W. , Halperin Stewart
Published: October 2006

The rate at which a chimpanzee approaches a hidden, distant goal varies according to social conditions and according to whether the goal is a novel object or food. This behavior furnishes a social group with sufficient information for simultaneous and successive discriminations between leaders and between goals.
Nascent Stage of Cellulose Biosynthesis
Authors: Leppard Gary G. , Sowden L. C. , Colvin J. Ross
Published: October 2006

Freeze-etching of never-dried pellicles or of incubated suspensions of both
Acetobacter xylinum
and
Acetobacter acetigenum
show a nascent form of the cellulose microfibril which has a core surrounded by an amorphous sheath. Drying of the pellicle or suspension reduces the diameter of the sheath and changes the form of the microfibril to the one usually seen. This nascent form of the cellulose microfibril is consistent with previous postulations of an intermediate polymer or polymers in the biosynthesis of cellulose.
Sensitive Period for the Development of Human Binocular Vision
Authors: Banks Martin S. , Aslin Richard N. , Letson Robert D.
Published: October 2006

Twenty-four subjects with abnormal binocular experience, due to a condition of convergent strabismus that existed during different periods of their lives, were tested. Interocular transfer of the tilt-aftereffect was used to assess binocularity. Individuals between 1 and 3 years of age are most susceptible to abnormal binocular experience.
Axonal Projections of Medial Preoptic and Anterior Hypothalamic Neurons
Authors: Conrad L. C. A. , Pfaff D. W.
Published: October 2006

Projections from medial preoptic area (mPOA) and medial anterior hypothalamic area (mAHA) neurons were investigated in albino rats with the use of tritiated amino acid autoradiography. Both the mPOA and the mAHA gave long-axon projections to structures in limbic forebrain and midbrain as well as short-axon projections to other hypothalamic regions. Differences between mPOA and mAHA neurons were observed in projections to the mid-septal region, ventromedial hypothalamus, premammillary region, and central gray. Further, while axons from the mPOA traveled within the medial forebrain bundle, those from the mAHA remained in a band ventromedial to the fornix. These anatomical differences may underlie functional differences between the mPOA and mAHA which have been demonstrated with other experimental techniques.
Direction Finding by Hornets Under Gravitational and Centrifugal Forces
Authors: Ishay Jacob , Sadeh Dror
Published: October 2006

The effect of centrifugal and gravitational forces whose resultant ranged between 26° and 45° on comb construction by hornet workers was assessed experimentally. Comb construction by hornets exposed to centrifugation at 1 to 2 days of age differed from that of hornets similarly exposed at 3 to 7 days of age. Juvenile hornets built their cells in the direction of the resultant force, whereas adults resisted the centrifugal force and tried to build in the direction of the gravitational force. Juveniles started their comb from the side walls, whereas adults started from the roof, as did nonspinning, control hornets. The findings suggest that hornets rapidly learn the gravitational force during the first days of life, and that they are aided by geometric cues of the breeding box to build in the direction of the force to which they had become habituated.
Phytoestrogens: Adverse Effects on Reproduction in California Quail
Authors: Leopold A. Starker , Erwin Michael , Oh John , Browning Bruce
Published: October 2006

Phytoestrogens, largely formononetin and genistein, are produced in the leaves of stunted desert annuals in a dry year. When ingested by California quail, these compounds apparently inhibit reproduction and prevent the production of young that will not have adequate food. In a wet year, forbs grow vigorously and phytoestrogenic substances are largely absent. Quail then breed prolifically and the abundant seed crop carries the enlarged population through the winter.
Experience Modifies the Plastic Properties of Identified Neurons
Authors: Murphey R. K. , Matsumoto S. G.
Published: October 2006

Crickets (
Acheta domesticus
) were reared in the presence of continuously repeating tone pulses. The responses of large abdominal interneurons to similar tone pulses were then compared. The giant interneurons of treated specimens are more resistant to habituation than those of control specimens.
Consequences of a Nationwide Ban on Spray Adhesives Alleged to Be Human Teratogens and Mutagens
Authors: Hook Ernest B. , Healy Kristine M.
Published: October 2006

A report of an association of chromosome breakage and birth defects with spray adhesive exposure resulted in a ban on the sale of these products and nationwide publicity warning exposed women. Six months later the ban was removed; the association could not be confirmed. Replies to questionnaires sent to medical genetics centers throughout the United States revealed that more than 1100 inquiries had been received and more than 1200 working days were expended because of the issue. Eleven exposed women underwent diagnostic amniocentesis, and one elected to abort her fetus. Eight other women who were exposed also elected to do so, but without first undergoing diagnostic amniocentesis. The episode illustrates some of the unexpected and unnecessary consequences that can arise from the false identification of an environmental agent as a mutagen or teratogen.
Selenium in Fly Ash
Authors: Gutenmann Walter H. , Bache Carl A. , Youngs William D. , Lisk Donald J.
Published: October 2006

Selenium, at concentrations exceeding 200 parts per million (ppm) (dry weight), has been found in white sweet clover voluntarily growing on beds of fly ash in central New York State. Guinea pigs fed such clover concentrated selenium in their tissues. The contents of the honey stomachs of bees foraging on this seleniferous clover contained negligible selenium. Mature vegetables cultured on 10 percent (by weight) fly ash-amended soil absorbed up to 1 ppm of selenium. Fly ashes from 21 states contained total selenium contents ranging from 1.2 to 16.5 ppm. Cabbage grown on soil containing 10 percent (by weight) of these fly ashes absorbed selenium (up to 3.7 ppm) in direct proportion (correlation coefficient
r
= .89) to the selenium concentration in the respective fly ash. Water, aquatic weeds, algae, dragonfly nymphs, polliwogs, and tissues of bullheads and muskrats from a fly ash-contaminated pond contained concentrations of selenium markedly elevated over those of controls.