Characterization of Bacillus thuringiensis isolates and their differential toxicity against Helicoverpa armigera populations

Bacillus thuringiensis isolates were characterized in rhizospheric cotton soils by using acetate selection process from eight different locations in South India. The fact that B. thuringiensis indices were higher in proportion in soil samples taken from Tamil Nadu and Karnataka than from Andhra Pradesh, indicates the abundance of B. thuringiensis populations in the cotton rhizosphere. Biochemical typing of the isolates designated eight local isolates (BtNg13, BtCo1, BtHyb7, BtAm2, BtRm5, BtWr3, BtPl 4, BtN 9), which belong to subspecies kurstaki, the most prevalent subspecies. Toxicity assays on American boll worm larval (F(1) ) populations collected from the Andhra Pradesh, Bangalore and Coimbatore regions, with a susceptible insect strain against different isolates of B. thuringiensis kurstaki spore-crystal mix, revealed distinct susceptibility patterns and specificity. The highest susceptibility was observed in the F(1) populations of Coimbatore, followed by Bangalore and Hyderabad populations, in comparison with the susceptible insect strain. Significant differences were observed (p < 0.0005 and CD = 5.3975) among Btk local isolates, H. armigera biotypes, Btk spore-crystal mix concentration and their interactions, through the Multifactorial ANOVA analysis. The toxicity of local B. thuringiensis isolates was higher than that of HD-1 (reference B.t.k strain). Indigenous Btk isolates have an enormous potential for the management of H. armigera in terms of development of resistance to HD-1. The present study would serve as a baseline data for future resistance monitoring of B. thuringiensis strains in H. armigera in Southern India.     

Dexamethasone mediated downregulation of PGC-1α and visfatin regulates testosterone synthesis and antioxidant system in mouse testis

Dexamethasone, a synthetic glucocorticoid has been used as an immunosuppressive and anti-inflammatory and affects reproduction. It has been suggested that testicular steroidogenesis involves PGC-1α and visfatin as key regulators. Previous studies have shown that dexamethasone down-regulates PGC-1α and visfatin expression in muscle and mammary epithelial cells respectively. However, the effect of dexamethasone on testicular visfatin and PGC-1α expressions has not been investigated. The aims of the present study were to investigate the effect of dexamethasone, on the expression of PGC-1α, visfatin and antioxidant enzymes activities in mouse testis. The results of the present study showed that dexamethasone treatment significantly decreased the expression of visfatin and PGC-1α in mice testis, along with significant decreased in testicular antioxidant enzymes activates. Further, dexamethasone treatment also significantly increased the testicular lipid peroxidation and decreased testosterone synthesis. The dexamethasone induced changes in PGC-1α and visfatin in the testis were significantly correlated with changes in serum testosterone concentrations and antioxidant enzymes activities. Thus, dexamethasone induced testicular toxicity may involve the PGC-1α and visfatin as important molecules to exhibit its effects.     

Insecticidal and repellent activity of Hiptage benghalensis L. Kruz (Malpighiaceae) against mosquito vectors

Plant-based insecticides for vector control are urgently needed for Anopheles barbirostris, Culex quinquefasciatus, and Aedes albopictus which are the primary vectors of malaria, lymphatic filariasis, and dengue, respectively, in India and other South East Asian countries. In the present study, larvicidal, adulticidal, and repellent activities of acetone root bark extract of Hiptage benghalensis were tested against the larvae and adults of the three mosquito vectors. The acetone root bark extracts of H. benghalensis was more effective as larvicides with low LC(50) (11.15-16.78?ppm) and LT50 (1.25-4.84?h at 200 and 400?ppm) values. Results of log probit analysis (at 95?% confidence level) and regression analysis of crude acetone root bark extract of H. benghalensis revealed that lethal concentration (LC(50)) values gradually decreased with the exposure periods; lethal time (LT(50)) decreased with the concentration, and the mortality is positively correlated with the concentration. The order of susceptibility of the three mosquito species was as follows: A. albopictus?>?A. barbirostris?>?C. quinquefascitus. Biochemical changes were also evidenced in third instar larvae of three mosquito species following a sublethal exposure for 24?h. The level of sugar, glycogen, lipids, and proteins was significantly (P?相似文献   

Intravitreal bevacizumab for the treatment of choroidal neovascularization secondary to pseudotumor cerebri

Background In pseudotumor cerebri (PTC), elevated intracranial pressure (ICP) results in papilledema and, rarely, choroidal neovascularization (CNV). Pseudotumor cerebri-induced CNV often regresses following medical or surgical ICP reduction, but additional treatments, such as photocoagulation, photodynamic therapy, peri-ocular steroid injections and/or subretinal surgery, may be necessary. Anti-angiogenic intravitreal injections have been shown to cause regression of both CNV and optic nerve edema. Case report We describe a patient with PTC and CNV whose CNV regressed and vision normalized after a single intravitreal injection of bevacizumab (Avastin; Genentech, San Francisco, CA).     

Effect of serotonergic agents on neuroleptic induced catalepsy in rats

Three pharmacological tools namely zimelidine, danitracen and MK 212, were selected to examine the nature of involvement of serotonergic neurotransmission in catalepsy, an undesirable side effect following administration of neuroleptics in rats. Reserpine and haloperidol were chosen as cataleptogenic challenges. Zimelidine, a serotonin (5-HT) reuptake blocker, inhibited the manifestation of reserpine and haloperidol induced catalepsy. However, a dose dependent effect could not be demonstrated beyond 30 mumoles/kg. Danitracen, a 5-HT receptor blocker, prevented the occurrence of the symptoms that were observed following reserpine treatment but it could not elicit blockade of haloperidol response. MK 212, an S2 (5-HT2) receptor stimulant forestalled the occurrence of reserpine syndrome at lower doses but exhibited cataleptogenic effects at higher doses. Besides, MK 212 failed to influence catalepsy following administration of haloperidol. It appears that 5-HT exerts a homoeostatic control in the regulatory neuraxis in neuroleptic induced neurological side effects.     

Quantifying cellular traction forces in three dimensions

Cells engage in mechanical force exchange with their extracellular environment through tension generated by the cytoskeleton. A method combining laser scanning confocal microscopy (LSCM) and digital volume correlation (DVC) enables tracking and quantification of cell-mediated deformation of the extracellular matrix in all three spatial dimensions. Time-lapse confocal imaging of migrating 3T3 fibroblasts on fibronectin (FN)-modified polyacrylamide gels of varying thickness reveals significant in-plane (x, y) and normal (z) displacements, and illustrates the extent to which cells, even in nominally two-dimensional (2-D) environments, explore their surroundings in all three dimensions. The magnitudes of the measured displacements are independent of the elastic moduli of the gels. Analysis of the normal displacement profiles suggests that normal forces play important roles even in 2-D cell migration.