Nicotinic-type unitary currents in Helix neurons

1. The platelet aggregation response to several known platelet agonists was evaluated in four Asian elephants. The platelets were highly responsive to stimulation with platelet-activating factor (PAF) and collagen, less responsive to adenosine diphosphate (ADP) and non-responsive to arachidonic acid, serotonin and epinephrine. 2. Arachidonic acid (1 x 10(-4) M), while inducing no aggregation, caused the release of 1248 +/- 1147 pg/ul (mean +/- SD) of thromboxane B2 (TXB2), the stable metabolite of thromboxane A2 from stimulated platelet. The addition of 1 x 10(-4) M ADP to platelets caused suboptimal aggregation and the release of only 25 +/- 10 pg TXB2/microliters. 3. The calcium channel blocker, verapamil, produced a dose-dependent inhibition of PAF-induced but not collagen-induced aggregation. The cyclooxygenase inhibitor, acetylsalicylic acid, produced no inhibition of either collagen- or PAF-induced aggregation.     

Effects of a kaolin-based particle film on oviposition and feeding of gypsy moth (Lep., Lymantriidae) and forest tent caterpillar (Lep., Lasiocampidae) in the laboratory

Abstract:  In the laboratory we investigated a kaolin-based crop protectant, Surround^® WP, that was mixed in a spray carrier (94% water, 2% methanol, 4% Triton X100) and applied as particle film against gypsy moth Lymantria dispar (L.) and forest tent caterpillar Malacosoma disstria Hubner. Paired-choice feeding tests showed that gypsy moth larvae were significantly (P < 0.05) less disposed to feed on red oak Quercus rubrus L. treated with high concentrations (60 and 120 g/l carrier) of kaolin than on untreated foliage. There was no significant difference (P > 0.05) between gypsy moth's consumption of kaolin-treated and untreated red oak when given a single food choice, but the adults were less inclined to oviposit on the kaolin-treated surfaces than on controls. However, no kaolin treatment completely deterred gypsy moth feeding or oviposition. Kaolin particle film did not influence forest tent caterpillar feeding and there were insufficient data to evaluate the effect of kaolin on the species' oviposition. The spray carrier did not increase the efficacy of the kaolin, but as an independent, albeit impractical treatment it constrained feeding by both insect species but did not affect gypsy moth oviposition. These initial laboratory findings suggest that applying kaolin-based particle film to forests would present significant challenges; but if these could be surmounted, the technique might assist in the management of gypsy moth but not likely in that of forest tent caterpillar.     

Porin OmpP2 of Haemophilus influenzae shows specificity for nicotinamide-derived nucleotide substrates

Haemophilus influenzae has an absolute requirement for NAD (factor V) because it lacks all biosynthetic enzymes necessary for de novo synthesis of that cofactor. Therefore, growth in vitro requires the presence of NAD itself, NMN, or nicotinamide riboside (NR). To address uptake abilities of these compounds, we investigated outer membrane proteins. By analyzing ompP2 knockout mutants, we found that NAD and NMN uptake was prevented, whereas NR uptake was not. Through investigation of the properties of purified OmpP2 in artificial lipid membrane systems, the substrate specificity of OmpP2 for NAD and NMN was determined, with KS values of approximately 8 and 4mm, respectively, in 0.1 m KCl, whereas no interaction was detected for the nucleoside NR and other purine or pyrimidine nucleotide or nucleoside species. Based on our analysis, we assume that an intrinsic binding site within OmpP2 exists that facilitates diffusion of these compounds across the outer membrane, recognizing carbonyl and exposed phosphate groups. Because OmpP2 was formerly described as a general diffusion porin, an additional property of acting as a facilitator for nicotinamide-based nucleotide transport may have evolved to support and optimize utilization of the essential cofactor sources NAD and NMN in H. influenzae.     

Chronic hypercapnia inhibits hypoxic pulmonary vascular remodeling

Chronic hypercapnia is commonly found in patients with severe hypoxic lung disease and is associated with a greater elevation of pulmonary arterial pressure than that due to hypoxia alone. We hypothesized that hypercapnia worsens hypoxic pulmonary hypertension by augmenting pulmonary vascular remodeling and hypoxic pulmonary vasoconstriction (HPV). Rats were exposed to chronic hypoxia [inspiratory O(2) fraction (FI(O(2))) = 0.10], chronic hypercapnia (inspiratory CO(2) fraction = 0.10), hypoxia-hypercapnia (FI(O(2)) = 0.10, inspiratory CO(2) fraction = 0.10), or room air. After 1 and 3 wk of exposure, muscularization of resistance blood vessels and hypoxia-induced hematocrit elevation were significantly inhibited in hypoxia-hypercapnia compared with hypoxia alone (P < 0.001, ANOVA). Right ventricular hypertrophy was reduced in hypoxia-hypercapnia compared with hypoxia at 3 wk (P < 0.001, ANOVA). In isolated, ventilated, blood-perfused lungs, basal pulmonary arterial pressure after 1 wk of exposure to hypoxia (20.1 +/- 1.8 mmHg) was significantly (P < 0.01, ANOVA) elevated compared with control conditions (12.1 +/- 0.1 mmHg) but was not altered in hypoxia-hypercapnia (13.5 +/- 0.9 mmHg) or hypercapnia (11.8 +/- 1.3 mmHg). HPV (FI(O(2)) = 0.03) was attenuated in hypoxia, hypoxia-hypercapnia, and hypercapnia compared with control (P < 0.05, ANOVA). Addition of N(omega)-nitro-L-arginine methyl ester (10(-4) M), which augmented HPV in control, hypoxia, and hypercapnia, significantly reduced HPV in hypoxia-hypercapnia. Chronic hypoxia caused impaired endothelium-dependent relaxation in isolated pulmonary arteries, but coexistent hypercapnia partially protected against this effect. These findings suggest that coexistent hypercapnia inhibits hypoxia-induced pulmonary vascular remodeling and right ventricular hypertrophy, reduces HPV, and protects against hypoxia-induced impairment of endothelial function.     

The gene encoding the nucleocapsid protein of Gill-associated nidovirus of Penaeus monodon prawns is located upstream of the glycoprotein gene

The ORF2 gene of Gill-associated virus (GAV) of Penaeus monodon prawns resides 93 nucleotides downstream of the ORF1a-ORF1b gene and encodes a 144-amino-acid hydrophilic polypeptide (15,998 Da; pI, 9.75) containing 20 basic (14%) and 13 acidic (9%) residues and 19 prolines (13%). Antiserum to a synthetic ORF2 peptide or an Escherichia coli-expressed glutathione S-transferase-ORF2 fusion protein detected a 20-kDa protein in infected lymphoid organ and gill tissues in Western blots. The GAV ORF2 fusion protein antiserum also cross-reacted with the p20 nucleoprotein in virions of the closely related Yellow head virus. By immuno-gold electron microscopy, it was observed that the ORF2 peptide antibody localized to tubular GAV nucleocapsids, often at the ends or at lateral cross sections. As GAV appears to contain only two structural protein genes (ORF2 and ORF3), these data indicate that GAV differs from vertebrate nidoviruses in that the gene encoding the nucleocapsid protein is located upstream of the gene encoding the virion glycoproteins.     

Serotonin 5-HT1A Receptor Activation Increases Cyclic AMP Formation in the Rat Hippocampus In Vivo

Abstract: In vivo microdialysis was used to examine the efflux of cyclic AMP (cAMP) into the extracellular fluid of the ventral hippocampus in the freely moving rat. The changes in extracellular cAMP concentration were monitored in response to forskolin and the serotonin 5-HT_1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT). The basal level of hippocampal extracellular cAMP was 2.3 ± 0.2 pmol/ml (n = 6), after a 3-h postsur- gery stabilisation period. Perfusion of forskolin (100 μM) through the probe for 30 min significantly increased the efflux of cAMP, which returned to baseline levels within 90 min. 8-OH-DPAT (0.3 mg/kg s.c.) also significantly increased cAMP efflux, whereas a similar volume of saline had no effect. Desensitisation of the 8-OH-DPAT-induced increase in cAMP efflux was observed following a second administration of 8-OH-DPAT after a 4-h interval. Administration of 8-OH-DPAT did not alter the efflux of cAMP when forskolin was perfused through the probe. Pretreatment with WAY 100135 [N-tert-butyl 3–4-(2-methoxyphenyl)piperazine-1 -yl-2-phenylpropanamide dihydrochloride] (5 mg/kg s.c.), a specific 5-HT_1A receptor antagonist, prevented the 8-OH-DPAT-induced increase in cAMP efflux. The data indicate that the 8-OH-DPAT-induced increase in cAMP efflux in vivo is mediated by a 5-HT_1A receptor.     

ATP-induced Secretion in PC12 Cells and Photoaffinity Labeling of Receptors

Abstract— Secretion of catecholamines by rat PC12 cells is strongly stimulated by extracellular ATP via a P₂-type pur-inergic receptor. ATP-induced norepinephrine release was inhibited 80% when extracellular Ca²⁺ was absent. Only four nucleotides, ATP, ATPγS, benzoylbenzoyl ATP (BzATP), and 2-methylthio-ATP, gave substantial stimulation of norepinephrine release from PC12 cells. ATP-induced secretion was inhibited by Mg²⁺, and this inhibition was overcome by the addition of excess ATP suggesting that ATP^4-was the active ligand. ATP-induced secretion of catecholamine release was enhanced by treatment of cells with pertussis toxin or 12- O -tetradecanoylphorbol 13-acetate. The stimulatory effects of 12- O -tetradecanoyl-phorbol 13-acetate and pertussis toxin on norepinephrine release were additive. After brief exposure of intact cells to the photoaffinity analog, [α-³²P]BzATP, two major proteins of 44 and 50 kDa and a minor protein of 97 kDa were labeled. An excess of ATP-γS and BzATP but not GTP blocked labeling of the proteins by [³²P]BzATP. Labeling of the 50-kDa protein was more sensitive to competition by 2-methylthio-ATP than the other labeled proteins, suggesting that the 50-kDa protein represents the P₂ receptor responsible for ATP-stimulated secretion in these cells.     

Church Festivals and the Visualization of Identity in Collingwood Bay,Papua New Guinea

In Collingwood Bay, people celebrate the individual saints after which each Anglican church is named. These church festivals are a combination of Christian worship and traditional music and dances. They vary from small, village-based happenings to large regional performances in which objects and food are exchanged. For the Maisin people, the festivals not only express dedication to the church, they also embody the spirit of past clan festivities that connected clans and commemorated clan ancestors. This article ¹ The research on which this article is based was financed by the Netherlands Foundation for the Advancement of Tropical Research (WOTRO) and the Radboud University of Nijmegen, Netherlands. An earlier version of this article was presented as a paper, “Performing Bodies—Constructing Identities: Church Festivals in Collingwood Bay, Papua New Guinea,” at the Annual Conference of the Australian Anthropological Society (AAS) in Melbourne in 2004. I thank the anonymous reviewer for Visual Anthropology for providing useful comments and suggestions. discusses how, for the Maisin people, church festivals provide a contemporary arena in which various identities, emotions, and knowledge as well as affiliations are actually embodied and expressed visually.