Effect of Metalaxyl on the incidence and severity of Pearl millet downy mildew disease in Northern Nigeria

Pearl millet downy mildew (DM) incidence, severity and yield losses of two pearl millet varieties (local and improved) due to the disease were determined in the field. Significant differences in the disease incidence and severity were recorded in the plots sown with metalaxyl-treated seeds and those sown with non-treated seeds, indicating the efficacy of the fungicide on the fungus. Yield losses due to non-treatment of seeds with metalaxyl was 40.88 and 45.39% in a local variety and 43.00 and 18.60% in an improved variety in the 2000 and 2001 cropping seasons respectively. Significant differences between plots sown with metalaxyl-treated and those sown with non-treated seeds were obtained for other yield components such as 1000-grains weight, panicle length and weight.     

Potent and selective nonpeptide inhibitors of caspases 3 and 7 inhibit apoptosis and maintain cell functionality

Caspases have been strongly implicated to play an essential role in apoptosis. A critical question regarding the role(s) of these proteases is whether selective inhibition of an effector caspase(s) will prevent cell death. We have identified potent and selective non-peptide inhibitors of the effector caspases 3 and 7. The inhibition of apoptosis and maintenance of cell functionality with a caspase 3/7-selective inhibitor is demonstrated for the first time, and suggests that targeting these two caspases alone is sufficient for blocking apoptosis. Furthermore, an x-ray co-crystal structure of the complex between recombinant human caspase 3 and an isatin sulfonamide inhibitor has been solved to 2.8-A resolution. In contrast to previously reported peptide-based caspase inhibitors, the isatin sulfonamides derive their selectivity for caspases 3 and 7 by interacting primarily with the S(2) subsite, and do not bind in the caspase primary aspartic acid binding pocket (S(1)). These inhibitors blocked apoptosis in murine bone marrow neutrophils and human chondrocytes. Furthermore, in camptothecin-induced chondrocyte apoptosis, cell functionality as measured by type II collagen promoter activity is maintained, an activity considered essential for cartilage homeostasis. These data suggest that inhibiting chondrocyte cell death with a caspase 3/7-selective inhibitor may provide a novel therapeutic approach for the prevention and treatment of osteoarthritis, or other disease states characterized by excessive apoptosis.     

Acute pharmacogenetic activation of medial prefrontal cortex excitatory neurons regulates anxiety-like behaviour

The medial prefrontal cortex (mPFC) is implicated in anxiety-like behaviour. In rodent models, perturbations of mPFC neuronal activity through pharmacological manipulations, optogenetic activation of mPFC neurons or cell-type specific pharmacogenetic inhibition of somatostatin interneurons indicate conflicting effects on anxiety-like behaviour. In the present study we examined the effects of pharmacogenetic activation of Ca²⁺/calmodulin-dependent protein kinase α (CamKIIα)-positive excitatory neurons on anxiety-like behaviour. We used clozapine-N-oxide (CNO) to pharmacogenetically activate virally delivered CamKIIα-hM3Dq-DREADD in mPFC excitatory neurons. The effects of acute CNO or vehicle treatment on anxiety-like behaviour in the open field and elevated plus maze tests were examined in rats virally infected with either CamKIIα-hM3Dq-DREADD or CamKIIα-GFP. In addition, the effects of acute CNO treatment on the expression of the neuronal activity marker c-Fos were examined in the mPFC as well as downstream target neuronal circuits using immunohistochemistry. Acute pharmacogenetic activation of mPFC excitatory neurons evoked a significant decrease in anxiety-like behaviour selectively on the elevated plus maze task, but not the open field test. Acute CNO treatment resulted in enhanced c-Fos-immunopositive cell number in the infralimbic, prelimbic and cingulate subdivisions of the mPFC. This was also accompanied by enhanced c-Fos-immunopositive cell number in multiple downstream circuits of the mPFC in CNO-treated hM3Dq animals. Acute pharmacogenetic activation of mPFC excitatory neurons reduces anxiety-like behaviour in a task-specific fashion accompanied by enhanced c-Fos expression in the mPFC and multiple target circuits implicated in the regulation of anxiety-like behaviour.     

Enhancing ligand–protein binding in affinity thermoprecipitation: Elucidation of spacer effects

Copolymers of N‐isopropylacrylamide and N‐acryloyl amino acid spacers of varying chain length were synthesized. p‐Aminobenzamidine (PABA) was chemically linked to the pendant carboxyl groups of these polymers to obtain thermoprecipitating affinity polymers. The inhibition constant (K_i) of these polymers for trypsin decreased, i.e., the efficiency of PABA–trypsin binding increased with increase in the spacer chain length. The polymer to which PABA was linked through a spacer of five methylene groups exhibited eleven times lower K_i than that of the polymer containing PABA without a spacer. Investigations on model inhibitors N‐acyl‐p‐aminobenzamidines showed that this enhancement in trypsin binding by the polymers was due to the spacer as well as to microenvironmental effects. Recovery and specific activity of the trypsin recovered increased with the spacer chain length. Separation of trypsin from a mixture of trypsin and chymotrypsin was also enhanced with the spacer chain length. The inhibition constants of these affinity polymers were not adversely affected by the crowding effect. © 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 64: 418–425, 1999.