scholarly journals Diminution of feeding response in Helicoverpa armigera by inhibition or silencing of sugar gustatory receptor

2019 ◽  
Author(s):  
Aniruddha R. Agnihotri ◽  
Sanyami S. Zunjarrao ◽  
Mukta Nagare ◽  
Rakesh S. Joshi
Keyword(s):  
Helicoverpa Armigera ◽  
Feeding Rate ◽  
Receptor Activation ◽  
Inhibitory Effect ◽  
Gustatory Receptor ◽  
Feeding Response ◽  
Downstream Signaling ◽  
Helicoverpa Armígera ◽  
Novel Strategy

ABSTRACTGustatory receptor (GR) is one of the essential chemosensory molecules in Lepidopteran pests. GR is involved in sensing several canonical tastes which in turn regulate the diverse behavioral and physiological responses of these insects. In this article, we have evaluated the alteration in feeding response of Helicoverpa armigera by blocking and silencing of sugar-sensing gustatory receptor 9 (HarmGr9). Sf9 cells based assay showed that glucose analogue, Miglitol, can bind to the expressed HarmGr9. This binding might lead to an inhibition of receptor activation and downstream signaling, indicated by reduced intracellular Ca2+ fluorescence. Further, the in-vivo study illustrated the feeding rate reduced on a diet containing miglitol as compared to the larvae fed on the artificial diet. Reduction in feeding rate was prolonged in insects fed on the miglitol containing diet even after switching to the control glucose diet. Competitive cell-based assay and feeding assay, using equimolar glucose and miglitol, also showed an inhibitory effect on HarmGr-9 activation and insect feeding rate. We have observed similar feeding rate reduction in HarmGr9 knockdown in H. armigera larvae. We believe this unique approach of H. armigera feeding response inhibition by blocking the sugar receptor can be further used to develop a novel strategy for agricultural pest management.

α2-Adrenergic-mediated tubular NO production inhibits thick ascending limb chloride absorption

2001 ◽  
Vol 281 (4) ◽  
pp. F679-F686 ◽  
Author(s):  
Craig F. Plato ◽  
Jeffrey L. Garvin
Keyword(s):  
Guanylate Cyclase ◽  
Soluble Guanylate Cyclase ◽  
Chloride Transport ◽  
Receptor Activation ◽  
Inhibitory Effect ◽  
No Production ◽  
Thick Ascending Limb ◽  
Chloride Absorption ◽  
Ly 83583

Stimulation of α2-adrenergic receptors inhibits transport in various nephron segments, and the thick ascending limb of the loop of Henle (THAL) expresses α2-receptors. We hypothesized that selective α2-receptor activation decreases NaCl absorption by cortical THALs through activation of NOS and increased production of NO. We found that the α2-receptor agonist clonidine (10 nM) decreased chloride flux ( J Cl) from 119.5 ± 15.9 to 67.4 ± 13.8 pmol · mm−1 · min−1 (43% reduction; P < 0.02), whereas removal of clonidine from the bath increased J Cl by 20%. When NOS activity was inhibited by pretreatment with 5 mM N G-nitro-l-arginine methyl ester, the inhibitory effects of clonidine on THAL J Clwere prevented (81.7 ± 10.8 vs. 71.6 ± 6.9 pmol · mm−1 · min−1). Similarly, when the NOS substrate l-arginine was deleted from the bath, addition of clonidine did not decrease THAL J Cl from control (106.9 ± 11.6 vs. 132.2 ± 21.3 pmol · mm−1 · min−1). When we blocked the α2-receptors with rauwolscine (1 μM), we found that the inhibitory effect of 10 nM clonidine on THAL J Cl was abolished, verifying that α2, rather than I1, receptors mediate the effects of clonidine in the THAL. We investigated the mechanism of NOS activation and found that intracellular calcium concentration did not increase in response to clonidine, whereas pretreatment with 150 nM wortmannin abolished the clonidine-mediated inhibition of THAL J Cl, indicating activation of phosphatidylinositol 3-kinase and the Akt pathway. We found that pretreatment of THALs with 10 μM LY-83583, an inhibitor of soluble guanylate cyclase, blocked clonidine-mediated inhibition of THAL J Cl. In conclusion, α2-receptor stimulation decreases THAL J Cl by increasing NO release and stimulating guanylate cyclase. These data suggest that α2-receptors act as physiological regulators of THAL NO synthesis, thus inhibiting chloride transport and participating in the natriuretic and diuretic effects of clonidine in vivo.

Coupling of M2 muscarinic receptors to ERK MAP kinases and caldesmon phosphorylation in colonic smooth muscle

2000 ◽  
Vol 278 (3) ◽  
pp. G429-G437 ◽  
Author(s):  
Amy K. Cook ◽  
Michael Carty ◽  
Cherie A. Singer ◽  
Ilia A. Yamboliev ◽  
William T. Gerthoffer
Keyword(s):  
Smooth Muscle ◽  
Map Kinase ◽  
Muscarinic Receptors ◽  
Map Kinases ◽  
Kinase Inhibitor ◽  
Receptor Activation ◽  
Inhibitory Effect ◽  
Subsequent Treatment ◽  
P38 Map Kinase

Coupling of M2 and M3 muscarinic receptors to activation of mitogen-activated protein (MAP) kinases and phosphorylation of caldesmon was studied in canine colonic smooth muscle strips in which M3 receptors were selectively inactivated by N, N-dimethyl-4-piperidinyl diphenylacetate (4-DAMP) mustard (40 nM). ACh elicited activation of extracellular signal-regulated kinase (ERK) 1, ERK2, and p38 MAP kinases in control muscles and increased phosphorylation of caldesmon (Ser789), a putative downstream target of MAP kinases. Alkylation of M3 receptors with 4-DAMP had only a modest inhibitory effect on ERK activation, p38 MAP kinase activation, and caldesmon phosphorylation. Subsequent treatment with 1 μM AF-DX 116 completely prevented activation of ERK and p38 MAP kinase and prevented caldesmon phosphorylation. Caldesmon phosphorylation was blocked by the MAP kinase/ERK kinase inhibitor PD-98509 but not by the p38 MAP kinase inhibitor SB-203580. These results indicate that colonic smooth muscle M2 receptors are coupled to ERK and p38 MAP kinases. Activation of ERK, but not p38 MAP kinases, results in phosphorylation of caldesmon in vivo, which is a novel function for M2receptor activation in smooth muscle.

scholarly journals Potensi Nematoda Patogen Serangga Steinernema spp. dalam Pengendalian Hama Utama Tanaman Kapas

2016 ◽  
Vol 1 (2) ◽  
pp. 101
Author(s):  
Heri Prabowo ◽  
I.G.A.A. Indrayani
Keyword(s):  
Helicoverpa Armigera ◽  
Insect Pests ◽  
Soil Surface ◽  
Tenebrio Molitor ◽  
Pectinophora Gossypiella ◽  
Helicoverpa Armígera ◽  
Soy Bean Oil

<p>Steinernema spp. memiliki potensi untuk mengendalikan hama tanaman kapas seperti Helicoverpa armigera dan Pectinophora gossypiella. Steinernema spp. mampu menyebabkan mortalitas P. gossypiella dan H. armi-gera berturut-turut sebesar 31,6–55,4 dan 46,3–63,8%. Steinernema spp. memiliki kemampuan membunuh lebih baik pada P. gossypiella, sedangkan kemampuan reproduksi dalam inangnya lebih baik pada H. armi-gera. Steinernema spp. mampu menginfeksi serangga inang lebih baik pada stadium ulat lebih tua diban-dingkan stadium muda. Steinernema spp. dapat diproduksi secara in vivo dan in vitro. Produksi secara in vivo dapat menggunakan Tenebrio molitor, Tirathaba rufivena, dan Attacus atlas. Produksi secara in vitro dapat menggunakan usus ayam, lemak sapi, dan minyak kedelai. Perlu dikembangkan formulasi Steinerne-ma spp. yang murah dan efektif untuk mengendalikan hama di atas permukaan tanah. Selain itu diperlukan pencarian isolat Steinernema spp. yang virulen dan cepat membunuh hama sasaran.</p><p> </p><p>Steinernema spp. could be potentially used for controlling H. armigera and P. gossypiella on cotton. Steiner-nema spp. causes mortality on P. gossypiella and H. armigera 31,6–55,4 and 46,3–63,8% respectively. The nematode causes a higher mortality on P. gossypiella than on H. armigera, however, produces more juvenile infective on H. armigera than on P. gossypiella. Higher successful infections of Steinernema spp. occurs on late larval stadium than on early one. Production of Steinernema spp. can be in vivo using Tenebrio molitor, Tirathaba rufivena, and Attacus atlas; and in vitro using chicken intestinum, cow lipid, and soy bean oil. For effecttively use, this nematode need to be formulated especially for controlling insect pests on soil surface, as well as finding the more virulent isolates against the target insects.</p>

scholarly journals The emerging role of the fibroblast growth factor-23–klotho axis in renal regulation of phosphate homeostasis

2007 ◽  
Vol 194 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Mohammed S Razzaque ◽  
Beate Lanske
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Fibroblast Growth Factor 23 ◽  
Ion Homeostasis ◽  
Experimental Studies ◽  
Receptor Activation ◽  
Fibroblast Growth ◽  
Phosphate Homeostasis ◽  
Downstream Signaling

Normal mineral ion homeostasis is tightly controlled by numerous endocrine factors that coordinately exert effects on intestine, kidney, and bone to maintain physiological balance. The importance of the fibroblast growth factor (FGF)-23–klotho axis in regulating mineral ion homeostasis has been proposed from recent research observations. Experimental studies suggest that 1) FGF23 is an important in vivo regulator of phosphate homeostasis, 2) FGF23 acts as a counter regulatory hormone to modulate the renal 1α-hydroxylase and sodium–phosphate cotransporter activities, 3) there is a trend of interrelationship between FGF23 and parathyroid hormone activities, 4) most of the FGF23 functions are conducted through the activation of FGF receptors, and 5) such receptor activation needs klotho, as a cofactor to generate downstream signaling events. These observations clearly suggest the emerging roles of the FGF23–klotho axis in maintaining mineral ion homeostasis. In this brief article, we will summarize how the FGF23–klotho axis might coordinately regulate normal mineral ion homeostasis, and how their abnormal regulation could severely disrupt such homeostasis to induce disease pathology.

scholarly journals Acute Glucocorticoid Administration Rapidly Suppresses Basal and Stress-Induced Hypothalamo-Pituitary-Adrenal Axis Activity

Endocrinology ◽  
2012 ◽  
Vol 153 (1) ◽  
pp. 200-211 ◽  
Author(s):  
Marcus H. Andrews ◽  
Susan A. Wood ◽  
Richard J. Windle ◽  
Stafford L. Lightman ◽  
Colin D. Ingram
Keyword(s):  
Glucocorticoid Receptor ◽  
Receptor Activation ◽  
Inhibitory Effect ◽  
Corticosterone Secretion ◽  
Glucocorticoid Administration ◽  
Corticosterone Response ◽  
Activity Marker ◽  
Corticosterone Release ◽  
Dose Dependent

Hypothalamo-pituitary-adrenal (HPA) axis activity is subject to negative feedback control by glucocorticoids. Although the rapid component of this feedback is widely considered to contribute to regulation of dynamic HPA activity, few in vivo data exist on the temporal and pharmacological characteristics of this phenomenon. Thus, frequent automated blood sampling was undertaken in rats to determine the effects of acute glucocorticoid administration on basal and stress-induced corticosterone secretion. The glucocorticoid agonist methylprednisolone (5–2000 μg) or dexamethasone (5–500 μg) injected iv at the peak of the diurnal rhythm caused dose-dependent suppression of basal corticosterone secretion, which was attenuated by the glucocorticoid receptor antagonist RU38486. With 50 μg methylprednisolone, the onset of this suppression occurred at 40 min and remained significant for 120 min. However, although higher doses led to a greater and more sustained suppression of endogenous corticosterone, the response was delayed by the emergence of an initial stimulatory response that imposed a finite minimum delay. A corticosterone response to injection of CRH (1 μg, iv) during the period of maximal suppression indicated a suprapituitary site for the inhibitory effect glucocorticoid activation. This mechanism was supported by glucocorticoid injection immediately before a psychological stress (30 min, white noise); methylprednisolone caused dose-dependent attenuation of stress-induced corticosterone release and expression of the activity marker c-fos mRNA in the paraventricular nucleus but did not block the pituitary response to CRH. Thus, in rats, glucocorticoid receptor activation rapidly suppresses basal and stress-induced HPA activity that operates, at least in part, through a central mechanism of action.

scholarly journals Phosphorylation of a Tyrosine Residue on Zap70 by Lck and Its Subsequent Binding via an SH2 Domain May Be a Key Gatekeeper of T Cell Receptor SignalingIn Vivo

2016 ◽  
Vol 36 (18) ◽  
pp. 2396-2402 ◽  
Author(s):  
Peter A. Thill ◽  
Arthur Weiss ◽  
Arup K. Chakraborty
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Receptor Activation ◽  
Sh2 Domain ◽  
Tcr Signaling ◽  
New Model ◽  
Downstream Signaling ◽  
Conventional Models

The initiation of signaling in T lymphocytes in response to the binding of the T cell receptor (TCR) to cognate ligands is a key step in the emergence of adaptive immune responses. Conventional models posit that TCR signaling is initiated by the phosphorylation of receptor-associated immune receptor activation motifs (ITAMs). The cytoplasmic tyrosine kinase Zap70 binds to phosphorylated ITAMs, is subsequently activated, and then propagates downstream signaling. While evidence for such models is provided by experiments with cell lines,in vivo, Zap70 is bound to phosphorylated ITAMs in resting T cells. However, Zap70 is activated only upon TCR binding to cognate ligand. We report the results of computational studies of a new model for the initiation of TCR signaling that incorporates thesein vivoobservations. Importantly, the new model is shown to allow better and faster TCR discrimination between self-ligands and foreign ligands. The new model is consistent with many past experimental observations, and experiments that could further test the model are proposed.

In Silico and in Vivo Investigations of Bioagent Helicoverpa Nucleopolyhedrovirus against Helicoverpa armigera in Chickpea

2021 ◽  
Vol 9 (2) ◽  
pp. 21-32
Author(s):  
Ritu Srivastava ◽  
◽  
Amritesh Chandra Shukla ◽  
Keyword(s):  
Green Tea ◽  
Rice Bran ◽  
Helicoverpa Armigera ◽  
Maximum Yield ◽  
3D Structure ◽  
Homology Model ◽  
In Vitro Toxicity ◽  
Helicoverpa Armígera

During investigations; homology model of 3D-structure was built for sequence of polyhedrin protein of Helicoverpa armigera nucleopolyhedrovirus, containing 246 amino acids (Accession: ACI05106.1 GI: 205946055), and evaluated through multiple tools/ applications to judge extent of accuracy in light of existing crystal structure. Further, in vivo experiments were conducted and determined response of different adjuvants with HaNPV and their efficacy. The pooled mean mortality of larvae exposed to virus mixed with 5% green tea and 5% rice bran filtrates (8.3 larvae per 25 plants) was differ significantly from control (15.8 larvae per 25 plants), suggesting that UV protectants & diet enhancer (mannitol) has ability to protect stability of virulence of the virus, under field conditions. The minimum percent pod damage of 8.6% and maximum yield of 1604.8 Kg ha-1 at harvesting was recorded with formulation of indigenous BHA virus isolate @ 2.2 x 105 POBs mL-1 mixed with Roket @50 ppm; followed by formulation with mannitol (@ 1% + green tea 5% + 5% rice bran filtrates) with percent pod damage of 16.8 % and yield of 1045.8 Kg ha-1 of chickpea. Furthermore, in vitro toxicity of fresh virus suspension @ 250 mL ha-1 was recorded more toxic in terms of percent mortality and LT50 (5.65 days). However, three months stored HaNPV formulations [(A) mannitol @ 1%+ green tea@ 5% and (B) mannitol @ 1% + green tea 5% + 5% rice bran filtrates] were more effective in larval reduction with LT50 of 7.89 and 6.00 days, respectively. Virus mixed with 5% green tea and 5% rice bran filtrates gave stability to formulation up-to one year with LT50 of 7.64 days. Findings showed that HaNPV formulations with mannitol (B) have potential that can be used in integrated manner with other IPM practices, to reduce the use of toxic synthetic pesticides in chickpea.

scholarly journals Interaction of Bacillus thuringiensis Toxins with Larval Midgut Binding Sites of Helicoverpa armigera (Lepidoptera: Noctuidae)

2004 ◽  
Vol 70 (3) ◽  
pp. 1378-1384 ◽  
Author(s):  
Anna Estela ◽  
Baltasar Escriche ◽  
Juan Ferr�
Keyword(s):  
Bacillus Thuringiensis ◽  
Concanavalin A ◽  
Helicoverpa Armigera ◽  
Binding Sites ◽  
Inhibitory Effect ◽  
Toxin Gene ◽  
Bt Cotton ◽  
Cry1ab Protein ◽  
Cry Proteins ◽  
Helicoverpa Armígera

ABSTRACT In 1996, Bt-cotton (cotton expressing a Bacillus thuringiensis toxin gene) expressing the Cry1Ac protein was commercially introduced to control cotton pests. A threat to this first generation of transgenic cotton is the evolution of resistance by the insects. Second-generation Bt-cotton has been developed with either new B. thuringiensis genes or with a combination of cry genes. However, one requirement for the “stacked” gene strategy to work is that the stacked toxins bind to different binding sites. In the present study, the binding of 125I-labeled Cry1Ab protein (125I-Cry1Ab) and 125I-Cry1Ac to brush border membrane vesicles (BBMV) of Helicoverpa armigera was analyzed in competition experiments with 11 nonlabeled Cry proteins. The results indicate that Cry1Aa, Cry1Ab, and Cry1Ac competed for common binding sites. No other Cry proteins tested competed for either 125I-Cry1Ab or 125I-Cry1Ac binding, except Cry1Ja, which competed only at the highest concentrations used. Furthermore, BBMV from four H. armigera populations were also tested with 125I-Cry1Ac and Cry1Ab to check the influence of the insect population on the binding results. Finally, the inhibitory effect of selected sugars and lectins was also determined. 125I-Cry1Ac binding was strongly inhibited by N-acetylgalactosamine, sialic acid, and concanavalin A and moderately inhibited by soybean agglutinin. In contrast, 125I-Cry1Ab binding was only significantly inhibited by concanavalin A. These results show that Cry1Ac and Cry1Ab use different epitopes for binding to BBMV.

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