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Stimulating Effects (stimulating + effects)
Selected AbstractsStimulating effects of the insecticide chlorpyrifos on host searching and infestation efficacy of a parasitoid waspPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 4 2002Halitiana Rafalimanana Abstract Hymenopterous parasitoids play an important role in the control of insect populations. During oviposition, Hymenopterous parasitoids use cues such as odours from their environment to locate their specific host. Leptopilina heterotoma (parasitoid of Drosophila larvae) locate their host by probing the substrate with the ovipositor. This behaviour can be induced by the odour of the host substrate alone. We analysed the sub-lethal effects of chlorpyrifos at LD20 on the probing activity in response to a fruit odour (banana). The insecticide increased the percentage of females spontaneously probing in response to the odour. Parasitoid females were then conditioned to associate banana odour with the oviposition in host larvae. This conditioning enables parasitoids to memorise the odour and to increase their probing response to this odour. During the olfactory conditioning, females exposed to the insecticide found and oviposited in host larvae more quickly than control females. One hour after the olfactory conditioning, females exposed to the insecticide presented a higher increase of their probing response to the odour than controls. Twenty-four hours after conditioning, the stimulation produced by chlorpyrifos was no longer perceptible, but the level of response of conditioned females was still higher than that of non-conditioned females, showing that odour memory was not impaired by the insecticide treatment. These sub-lethal effects, that stimulate host searching by parasitoids without impairing odour memorisation, could increase their parasitic efficiency. © 2002 Society of Chemical Industry [source] The influence of natural variations in maternal care on play fighting in the ratDEVELOPMENTAL PSYCHOBIOLOGY, Issue 8 2008Carine I. Parent Abstract Naturally occurring variations in maternal care in the rat influence the sensitivity of offspring to stress in adulthood. The offspring of mothers that show lower levels of pup licking/grooming (i.e., low-LG mothers) demonstrate enhanced responses to stress and increased anxiety compared to those of high-LG mothers. Low-LG offspring are also more sensitive to the influence of environmental enrichment than high-LG offspring. This study examined play fighting in the juvenile offspring of high-LG and low-LG dams in a multiple-play partners housing environment. Male offspring from low-LG dams demonstrated a significantly higher frequency of pouncing, pinning and aggressive social grooming than did high-LG males and high-LG and low-LG females. Consistent with earlier reports, male pups engaged in more play fighting than did females and maternal care was associated with differences in play fighting but only in males. Lower levels of stimulation in the form of LG from the dam during perinatal development may thus increase sensitivity for the stimulating effects of play behavior in periadolescence, in part explaining the increased solicitation of play fighting through increased pouncing in the male offspring of the low-LG mothers. These findings identify a possible influence of variations in maternal care on play fighting and suggest that maternal care in the perinatal period influence social interactions during periadolescence. © 2008 Wiley Periodicals, Inc. Dev Psychobiol 50: 767,776, 2008 [source] Impaired M-Current and Neuronal ExcitabilityEPILEPSIA, Issue 2002Motohiro Okada Summary: ,Purpose: Benign familial neonatal convulsions (BFNC), a hereditary epilepsy, occurs specifically in newborns and remits spontaneously after this period. Several mutations of either KCNQ2 or KCNQ3, members of the KCNQ-related K+ -channel (KCNQ-channel) family, were identified as a cause of BFNC. Such mutations impair KCNQ-related M- current, an element of the inhibitory system in the central nervous system (CNS), and therefore are thought to result in neuronal hyperexcitability. Methods: To clarify the pathogenesis of BFNC, this study investigated the effects of the KCNQ channel on propagation of neuronal excitability using a 64-channel multielectrode dish (MED64) system for novel two-dimensional monitoring of evoked field potentials including fiber volley (FV) and field excitatory postsynaptic potential (fEPSP). Results: Dup996, a selective KCNQ-channel inhibitor, did not affect the amplitude of FV or fEPSP, but enhanced the FV and fEPSP propagation. The ,-aminobutyric acid (GABA)A -receptor antagonist, bicuculline, enhanced their propagation, whereas ,-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)/glutamate-receptor antagonist, DNQX, reduced both amplitude and propagation of fEPSP without affecting those of FV. Under the condition of GABAA -receptor blockade by bicuculline, Dup996 enhanced the amplitude of fEPSP and propagation of FV and fEPSP without affecting the amplitude of FV. Dup996 enhanced the stimulating effects of bicuculline on the propagation and amplitude of FV and fEPSP, but it did not affect the inhibiting effects of DNQX. Conclusions: These results suggest that the occurrence of BFNC cannot be produced by KCNQ-channel dysfunction alone but by reciprocal action between impaired KCNQ channel and the other unknown. [source] Analysis of gene expression profiles in human HL-60 cell exposed to cantharidin using cDNA microarrayINTERNATIONAL JOURNAL OF CANCER, Issue 2 2004Jun-Ping Zhang Abstract Cantharidin is a natural toxin that has antitumor properties and causes leukocytosis as well as increasing sensitivity of tumor cells resistant to other chemotherapeutic agents. There is limited information, however, on the molecular pharmacological mechanisms of cantharidin on human cancer cells. We have used cDNA microarrays to identify gene expression changes in HL-60 promyeloid leukemia cells exposed to cantharidin. Cantharidin-treated cells not only decreased expression of genes coding for proteins involved in DNA replication (e.g., DNA polymerase delta), DNA repair (e.g., FANCG, ERCC), energy metabolism (e.g., isocitrate dehydrogenase alpha, ADP/ATP translocase), but also decreased expression of genes coding for proteins that have oncogenic activity (e.g., c-myc, GTPase) or show tumor-specific expression (e.g., phosphatidylinositol 3-kinase). In contrast, these treated cells overexpressed several genes that encode intracellular and secreted growth-inhibitory proteins (e.g., BTG2, MCP-3) as well as proapoptotic genes (e.g., ATL-derived PMA-responsive peptide). Our findings suggest that alterations in specific genes functionally related to cell proliferation or apoptosis may be responsible for cantharidin-mediated cytotoxicity. We also found that exposure of HL-60 cells to cantharidin resulted in the decreased expression of multidrug resistance-associated protein genes (e.g., ABCA3, MOAT-B), suggesting that cantharidin may be used as an oncotherapy sensitizer, and the increased expression of genes in modulating cytokine production and inflammatory response (e.g., NFIL-3, N-formylpeptide receptor), which may partly explain the stimulating effects on leukocytosis. Our data provide new insight into the molecular mechanisms of cantharidin. © 2003 Wiley-Liss, Inc. [source] Linkage and QTL mapping for Sus scrofa chromosome 12JOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 2003G. Yue Summary The SSC12 (Sus scrofa chromosome 12) linkage and QTL maps were generated using 11 markers, of which seven to 10 have been used in the three F2 families based on Wild Boar (W), Meishan (M) and Pietrain (P) crosses. Linkage maps showed identical marker order among the families, but differed in total lengths. They were in agreement with the already published maps, except for the order SWR1021,SW605. Most quantitative trait loci (QTLs) affected fat or meat content in carcass, but were also found for some other traits (heart weight, CK20 values and teat number). They explained up to 5.4% of F2 phenotypic variance. Meishan alleles had stimulating effects on fat deposition and decreasing effects on lean content and CK20 value. The QTL profiles differed between families, with QTL effects in the vicinity of the GH1 locus found solely in the M × P family. Zusammenfassung Auf der Basis von elf Markern wurden Kopplungs- und QTL-Karten für Chromosom 12 (SSC12) in drei F2 -Familien aus Kreuzungen von Wildschwein (W), Meishan (M) und Pietrain (P) erstellt. Hierbei wurden sieben bis zehn Marker pro F2 -Familie benutzt. Die Kopplungskarten zeigten eine gleichartige Anordnung der Loci für alle Familien, jedoch mit verschiedenen Kartenlängen. Sie stimmen, außer in der Anordnung SWR1021,SW605, mit bereits publizierten Karten überein. Quantitative Trait Loci (QTLs) waren hauptsächlich für Merkmale des Fett-oder Fleischanteils im Schlachtkörper festzustellen, daneben aber auch für weitere Merkmale (Herzgewicht, CK20 -Wert, Zitzenzahl). Sie erklärten bis zu 5,4% der phänotypischen Varianz in der F2 -Generation. Meishan-Allele waren assoziiert mit einer Steigerung des Fettansatzes sowie einer Reduktion der Anteile wertvoller Teilstücke und der CK20 -Werte. Die QTL-Profile unterschieden sich zwischen den Familien und ließen Assoziationen mit dem GH1 -Locus nur in der Familie M × P erkennen. [source] Sensitization of Ventral Tegmental Area Dopamine Neurons to the Stimulating Effects of EthanolALCOHOLISM, Issue 9 2009Zheng-Ming Ding Background:, Previous studies indicated that chronic alcohol drinking increased the sensitivity of the posterior ventral tegmental area (p-VTA) to the reinforcing effects of ethanol. The current study tested the hypothesis that local exposure of the p-VTA to ethanol would increase the sensitivity of dopamine (DA) neurons to the stimulating effects of ethanol. Methods:, Experiment 1 examined the stimulating effects of ethanol in the p-VTA after a 7-day ethanol pretreatment in the p-VTA. Adult female Wistar rats were pretreated with microinjections of 200 mg% ethanol or artificial cerebrospinal fluid (aCSF) into the p-VTA once a day for 7 days. On the eighth day, rats received a challenge injection of ethanol (100, 200, or 300 mg%) or aCSF into the p-VTA, and extracellular DA levels were measured in the nucleus accumbens (NAc) shell with microdialysis. Experiment 2 examined the stimulating effects of ethanol (200 mg%) after a 3- or 5-day ethanol (200 mg%) pretreatment in the p-VTA. Experiment 3 examined the stimulating effects of ethanol (200 mg%) 7 days after the last of the 7-day ethanol (200 mg%) pretreatments in the p-VTA. Results:, Experiment 1: in both aCSF- and ethanol-pretreated rats, the challenge microinjection of ethanol dose-dependently increased DA release in the NAc shell, with significantly greater increases in ethanol-pretreated groups. Experiment 2: the 5-day, but not 3-day, ethanol pretreatment protocol increased the response of p-VTA dopamine neurons to the ethanol challenge. Experiment 3: the increased stimulating effects of ethanol were still evident after 7 days. Conclusions:, The results indicate that repeated local ethanol exposure of the p-VTA produced neuroadaptations in DA neurons projecting to the NAc shell, resulting in a persistent increase in the sensitivity of these neurons to the stimulating effects of ethanol. [source] The effects of vasoactive agents, platelet agonists and anticoagulation on thrombelastographyACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2007J. Kawasaki Background:, Platelet activation is a critical step in primary hemostasis and clot formation. We tested a hypothesis that platelet stimulating effects of vasoactive agents or platelet agonists could be shown using thrombelastography (TEG®) as faster onset or increased clot strength. We further examined if TEG® could be modified to evaluate activated platelets as a reversal of anticoagulation in the presence of partial thrombin inhibition. Methods:, Blood samples were obtained from 126 non-cardiac surgical patients. Effects of vasoactive agents on TEG® and aggregometry were examined using epinephrine, norepinephrine, vasopressin, desmopressin acetate, milrinone and olprinone (Experiment I). Platelet agonists (epinephrine, ADP and collagen) were separately tested on TEG® (Experiment II). Effects of platelet agonists (ADP and collagen) on TEG® under anticoagulation in the absence or presence of abciximab were studied (Experiment III). We also tested antiplatelet effects of milrinone and olprinone in the presence of anticoagulants on TEG® (Experiment IV). Results:, Neither vasoactive agents nor platelet agonists affected TEG® or aggregometry results except for milrinone and olprinone on aggregometry (Experiment I, II). Platelet agonists facilitated clotting in the presence of anticoagulants (Experiment III). Abciximab-treated platelets still exhibited procoagulant effects in the presence of heparin, while not in the presence of argatroban (Experiment III). Platelet inhibition on the modified TEG® was more extensive with milrinone than olprinone, and it was dose dependent (Experiment IV). Conclusion:, Modified TEG® using heparin or argatroban might delineate the procoagulant effects of platelets by adding platelet specific agonist. [source] Rheumatoid arthritis fibroblast-like synoviocytes express BCMA and are stimulated by APRILARTHRITIS & RHEUMATISM, Issue 11 2007Katsuya Nagatani Objective Fibroblast-like synoviocytes (FLS) are among the principal effector cells in the pathogenesis of rheumatoid arthritis (RA). This study was undertaken to examine the variety of stimulating effects of APRIL and its specific effect on FLS in the affected RA synovium. Methods Synovium and serum samples were obtained from patients with RA, patients with osteoarthritis (OA), and healthy subjects. Soluble APRIL proteins were assayed by enzyme-linked immunosorbent assay. The relative gene expression of APRIL, BCMA, interleukin-6 (IL-6), tumor necrosis factor , (TNF,), IL-1,, and RANKL was assessed in RA and OA FLS by polymerase chain reaction. Effects of APRIL on the production of proinflammatory cytokines and RANKL in RA FLS were investigated by flow cytometry and with the use of a BCMA-Fc fusion protein. Results A significantly higher level of soluble APRIL was detected in RA serum compared with normal serum. Among the 3 receptors of APRIL tested, RA FLS expressed only BCMA, whereas OA FLS expressed none of the receptors. APRIL stimulated RA FLS, but not OA FLS, to produce IL-6, TNF,, IL-1,, and APRIL itself. In addition, APRIL increased RA FLS expression of RANKL and also enhanced progression of the cell cycle of RA FLS. Neutralization of APRIL by the BCMA-Fc fusion protein attenuated all of these stimulating effects of APRIL on RA FLS. Conclusion RA FLS are stimulated by APRIL and express the APRIL receptor BCMA. These results provide evidence that APRIL is one of the main regulators in the pathogenesis of RA. [source] Starch phosphorylation,Maltosidic restrains upon 3,- and 6,-phosphorylation investigated by chemical synthesis, molecular dynamics and NMR spectroscopyBIOPOLYMERS, Issue 3 2009Peter I. Hansen Abstract Phosphorylation is the only known in vivo substitution of starch, yet no structural evidence has been provided to explain its implications of the amylosidic backbone and its stimulating effects on starch degradation in plants. In this study, we provide evidence for a major influence on the glucosidic bond in starch specifically induced by the 3-O-phosphate. Two phosphorylated maltose model compounds were synthesized and subjected to combined molecular dynamics (MD) studies and 950 MHz NMR studies. The two phosphorylated disaccharides represent the two possible phosphorylation sites observed in natural starches, namely maltose phosphorylated at the 3,- and 6,-position (maltose-3,-O-phosphate and maltose-6,-O-phosphate). When compared with maltose, both of the maltose-phosphates exhibit a restricted conformational space of the ,(1,4) glycosidic linkage. When maltose is phosphorylated in the 3,-position, MD and NMR show that the glucosidic space is seriously restricted to one narrow potential energy well which is strongly offset from the global potential energy well of maltose and almost 50°degrees from the , angle of the ,-maltose crystal structure. The driving force is primarily steric, but the configuration of the structural waters is also significantly altered. Both the favored conformation of the maltose-3,-phosphate and the maltose-6,-phosphate align well into the 6-fold double helical structure of amylopectin when the effects on the glucosidic bond are not taken into account. However, the restrained geometry of the glucosidic linkage of maltose-3,-phosphate cannot be accommodated in the helical structure, suggesting a major local disturbing effect, if present in the starch granule semi-crystalline lattice. © 2008 Wiley Periodicals, Inc. Biopolymers 91: 179,193, 2009. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] | |||||||||||||