Swim Stress Increases the Potency of Glycine at the N-Methyl-d-Aspartate Receptor Complex

Abstract: We have previously demonstrated that chronic administration of antidepressants results in a reduction in the potency of glycine to displace 5,7-[³H]dichlorokynurenic acid (5,7-[³H]-DCKA) from the strychnine-insensitive glycine recognition site of the NMDA receptor complex. We now report that exposure of rats to the forced swim test results in a 56% increase in the potency of glycine to displace 5,7-[³H]DCKA from frontal cortical homogenates. These data are consistent with the hypothesis that the forced swim test, a preclinical screen sensitive to acute administration of antidepressant drugs and NMDA receptor antagonists, also results in adaptation of the NMDA receptor complex. Moreover, these data lend further support to the hypothesis that glutamatergic pathways are involved in the neurobiological response to stress and, potentially, in the pathophysiology of depression.     

Intramolecular domain-domain interactions and intermolecular self-association in bovine prothrombin. A potentiometric and laser light-scattering study

The interaction of bovine prothrombin with Ca²⁺ and Mg²⁺ ions was investigated by following H⁺ release as a function of metal ion concentration at pH 6 and pH 7.4 at high and low ionic strength. Prothrombin Ca²⁺ and Mg²⁺ binding is characterized by high- and low-affinity sites. M²⁺ binding at these sites is associated with intramolecular conformational changes and also with intermolecular self-association. The pH dependence of H⁺ release by M²⁺ is bell shaped and consistent with controlling pK_a values of 4.8 and 6.5. At pH 6 and low ionic strength, both Ca²⁺ and Mg²⁺ titrations following H⁺ release clearly show independent low- and high-affinity binding sites. Laser light scattering reveals that at pH 7.4 and low ionic strength, and at pH 6.0 and high ionic strength, the prothrombin molecular weight is between 73 and 98 kD. At pH 7.4 and high ionic strength, prothrombin is monomeric in the absence of metal ions, but appears to dimerize in the presence of M²⁺. At pH 6.0 and low ionic strength prothrombin exists as a dimer in the absence of metal ions and is tetrameric in the presence of Ca²⁺ and remains dimeric in the presence of Mg²⁺. These results and those for metal ion-dependent H⁺ release indicate that H⁺ release occurs concomitantly with association processes involving prothrombin.Abbreviations GLA -carboxyglutamic acid; fragment 1. amino terminal residues 1–156 of bovine prothrombin - MES 2-(N-morpholino) ethanesulfonic acid - MOPS 3-(N-morpholino) propanesulfonic acid - PS/PC phosphatidylserine/phosphatidylcholine vesicles - ionic strength     

Behavioral adaptations of two phytophagous insects feeding on two species of phototoxic Asteraceae

Two phototoxic plants of the Asteraceae family were studied in relation to species of phytophagous insects for which they are hosts:Argyrotaenia velutinana Wlk. feeding onChrysanthemum leucanthemum L. andChlorochlamys chloroleucaria (Guenée) colonizingRudbeckia hirta L. The toxicity of these two plants is related to the presence of acetylenes and thiophenes that induce a light-mediated production of deleterious singlet oxygen and other free radicals (phototoxicity). Results showed that females ofA. velutinana laid their eggs preferentially in the shade and the larvae adopted hiding behaviors, such as bending of ligulate corollas and silk spinning to build opaque shelters. By avoiding direct exposure to the sun, both behaviors may reduce phototoxicity associated with ingested plant materials. Furthermore, larvae ofC. chloroleucaria demonstrated a preference in the field for pollen, which constitutes a nonphototoxic tissue of their host plant. Experimental alterations of these specific behaviors induced important biological consequences for larvae of both insects such as mortality or reduction of larval growth rate. These results reinforce the idea that behavior may constitute an efficient adaptation to avoid phototoxicity.     

In vitro autoradiographic localization of vasoactive intestinal peptide (VIP) binding sites in the rat central nervous system

This paper describes the autoradiographic distribution of VIP binding sites in the rat central nervous system using monoiodinated ¹²³I-labeled VIP. High densities of VIP binding sites are observed in the granular layer of the dorsal dentate gyrus of the hippocampus, the basolateral amygdaloid nucleus, the dorsolateral and median geniculate nuclei of the thalamus as well as in the ventral part of the hypothalamic dorsomedial nucleus.     

Interaction of peanut agglutinin,a lectin specific for nonreducing terminal d-galactosyl residues,with embryonal carcinoma cells

Peanut agglutinin (PNA), a lectin specific for terminal d-galactosyl residues, was found to react with embryonal carcinoma cells, but not with their differentiated derivatives. Receptors for PNA were detectable at the surface of all cells of the quasinullipotent F9 line and on only 50% of the multipotent PCC3/A/1 line. The fraction of the PCC3/A/1 population which expresses the F9 antigen was found to be included in the subpopulation carrying the PNA receptors. PNA⁺ and PNA^? subpopulations of PCC3/A/1 were separated by a PNA-mediated reversible agglutination of PNA⁺ cells with rabbit erythrocytes. These subpopulations were essentially F9⁺ and F9^?, respectively.     

Potential of ultraviolet radiation for control of american cockroach populations

Populations of Periplaneta americana (L.) were exposed for 8–20 week periods in specially designed rooms to 254 nm UV at low intensity (50–115 ergs sec^–1cm^–2), high intensity (160–220 ergs sec^–1cm^–2), or to white light. The rooms contained tables and chairs to simulate occupied space, with food and water placed in positions exposed to UV radiation. General irradiation (where the whole room was exposed to UV) at 115 ergs sec^–1cm^–2 and above was effective in producing high mortality in all stages except 8–10th instar nymphs and adults. Hot-spots irradiation (where UV lamps were placed behind table and chair harborages) produced high mortality only in 1 st-3rd instar nymphs which would result in slower elimination of a population. Crude aggregation pheromone was not successful in holding cockroaches close to radiation sources or substantially increasing mortality under the conditions of the experiments.

---

Zusammenfassung Populationen von Periplaneta americana (L.), die hinsichtlich ihrer Alterszusammensetzung (2.–3.; 5–6.; 8.–10. und adultes Stadium) und der Anzahlen in jedem Stadium festgelegt waren, wurden für 8–20 Wochenperioden in speziell dafür entworfenen Räumen einer 254 nm UV-Bestrahlung mit geringer (50–115 erg sec^–1cm^–2) oder hoher (160–220 erg sec^–1cm^–2) Intensität oder weißem Licht (als Kontrolle) ausgesetzt. Die Räume enthielten Tische und Stühle, um bewohnten Raum mit natürlichen Zufluchtsstätten mit Nahrung und Wasser an Stellen, die der UV-Bestrahlung unterlagen, zu simulieren. Ganzraumbestrahlung mit 115 erg sec^–1cm^–2 und darüber erzeugte hohe Mortalität bei 1.–3. und 5.–6.-Larvenstadien, örtliche Bestrahlung (UV-Lampen hinter Tisch- und Stuhl-Zufluchtsstätten) dagegen nur beim 1.–3.-Stadium, was zu einer langsameren Ausrottung einer Population führen würde. Ungereinigtes Aggregationspheromon als Zusatz, um Schaben dicht an die UV-Quellen zu locken und sie hier zu halten, war offenbar unwirksam, da eben die Mortalität nicht signifikant zunahm. Dieses Versagen war in erster Linie auf die Konkurrenz mit der Fülle von natürlichem Pheromon, das von den gewohnten Zufluchtsstätten ausging, zurückzuführen, verbunden mit der dem UV-Licht innewohnenden Abschreckung. Dennoch darf man annehmen, daß UV-Bestrahlung einen bedeutsamen Wert für die Verhinderung eines Populationswachstums (durch Ausschalten junger Larvenstadien) besitzt, besonders dort, wo chemische Bekämpfung aus Gesundheits- und Sicherheitsgründen oder wegen gesetzlichen Einschränkungen nur begrenzt möglich ist.

     

Extremely rapid degradation of [3H] methionine-enkephalin by various rat tissues in vivo and in vitro

Thirty sec after the intrajugular injection of [³H] methionine-enkephalin (met-enkephalin) in the rat, the radioactivity was already distributed in an apparent volume of 53 ml and the metabolic clearance rate calculated from the characteristics of the plasma disappearance curve was 10 ml/min. As shown by partition chromatography plasma extracts obtained 15 sec after injection of [³H] met-enkephalin, only 5% of the total radioactivity migrated as the intact pentapeptide, while no detectable intact pentapeptide remained 2 min after injection, thus indicating a half-life of [³H] met-enkephalin of the order of 2 to 4 sec. Incubation of rat cerebral tissue with [³H] met-enkephalin indicates that the first step in the breakdown of met-enkephalin in both plasma and brain tissue is cleavage of the Tyr-Gly amide bond. These data offer an explanation for the low activity of met-enkephalin after intraventricular or intravenous administration.     

Leishmania mexicana: Immunology and histopathology in C3H mice

C3H mice were infected subcutaneously with 10⁵ promastigotes of Leishmania mexicana and subsequent lesions were examined at 3, 5, and 8 months. All animals developed persistent nonulcerating nodules of variable size which did not metastasize. The nodules contained amastigotes with a mononuclear infiltrate of histiocytes, lymphocytes, and plasma cells, but without formation of tuberculoid-type granulomas. Neutrophils and eosinophils were also encountered in some cases. Specific antileishmanial antibodies and delayed-type hypersensitivity to leishmanial antigen were present at 3, 5, and 8 months postinfection. L. mexicana infection in C3H mice differs from classic self-healing cutaneous leishmaniasis by the pesistence of nonhealing, nonulcerating, nonmetastasizing lesions, despite evidence of cellular and humoral immunity.     

Purification of cytoplasmic antigens from the mycelial phase of Candida albicans: Possible advantages of its use in Candida serology

The serology of candidiasis is complicated by the use of poorly defined antigens. Total extracts of the yeast phase have been commonly used as cytoplasmic antigen, without regard to the significant amounts of carbohydrate that may contaminate such preparations. This is particularly true in the case of commercially available antigens that have been used as cytoplasmic antigens but actually are richer in carbohydrate than in protein. Affinity chromatography in concanavalin A — Sepharose provides a simple procedure to separate carbohydrates, mainly mannan, from protein antigens in whole Candida extracts. By using mannan-poor antigens, the specificity of serological reactions can be increased considerably, since both the positive reactions seen in asymptomatic donors and the cross-reactions seen in patients infected with other fungi are due to anti-mannan antibodies. In contrast, both anti-mannan and anti-cytoplasmic antigen antibodies can be detected in patients suspected of systemic candidiasis. On the other hand, absolute specificity may never be achieved for systemic candidiasis. We have found antibodies against cytoplasmic antigen in a patient allergic to C. albicans, in whom the microorganism was isolated from fecal material. It appears that, under favorable conditions, mucosal sensitization may also trigger a systemic reaction directed against both mannan and cytoplasmic antigens.Publication no. 341 from The Department of Basic and Clinical Immunology and Microbiology, Medical University of South Carolina.     

Alveld-Producing Saponins

Stabursvik (1959) described the saponin fraction of Narthecium ossifragum as a sarsasapogenin glycoside with the structure arabinosegalactose-xylose-glucose-sarsasapogenin. In a renewed study of the phototoxic lamb disease alveld, in which this saponin has been implicated (Ender 1955), we have looked more closely at the saponin fraction. We find that there are two saponins, one major and one minor. Both have a branched trisaccharide on C-3 of the sapogenin. Galactose is directly attached to C-3 in both saponins. The major saponin has glucose and arabinose attached to galactose, the minor saponin has glucose and xylose. We suggest the names narthecin and xylosin for the spirostanol form of these two saponins. In fresh juice from leaves we find little narthecin, however. Most of the saponin is present in the furostanol form, with glucose on C-26. Enzymatic hydrolysis showed this glucose to be bound as a β-glucoside. From specific rotations in partial hydrolysates we conclude that the saccharide on C-3 is a β-D-glucoside, α-L-araboside, β-D-galactoside.