Effect of temperature, relative humidity and aphid developmental stage on the efficacy of the mycoinsecticide Mycotal® against Myzus persicae

The green peach aphid, Myzus persicae, is a major pest worldwide. An examination of the impact of temperature, relative humidity and developmental stages of M. persicae on the efficacy of the whitefly mycoinsecticide Mycotal®, based on Lecanicillium muscarium and the effects of infection on aphid fecundity was evaluated under controlled conditions. Although this fungus can be grown at a broad range of temperatures (15-30oC), the optimum temperature for control of M. persicae ranged between 20 and 30oC. L. muscarium had high efficacy as a microbial control against M. persicae between 55 and 90% relative humidity. Total mortality of aphids treated with different spore dosages of L. muscarium varied according to the developmental stage: adults, fourth and third instar nymphs of proved more susceptible than first instar nymphs. Although the fungus did not affect the rate of nymph production, the reproductive period of aphids significantly decreased with increasing the spore dosage. Thus, total fecundity of treated aphids was 22.6 ± 1.1 and 31.6 ± 2.4 offspring per adult at the medium (644 ± viable spore/mm2) and low (330 ± 40 viable spore/mm2) dosages, compared with 45.7 ± 4.3 offspring per untreated aphid. The results suggest that L. muscarium has the potential as a biological control agent of M. persicae. However, fungal infection appears to have no sub-lethal effects on the fitness of the host’s progeny

Hydrogen sulfide inhibits calcification of heart valves; implications for calcific aortic valve disease

This is the final version. Available from the publisher via the DOI in this record.Background and Purpose: Calcification of heart valves is a frequent pathological finding in chronic kidney disease and in elderly patients. Hydrogen sulfide (H2S) may exert anti-calcific actions. Here we investigated H2S as an inhibitor of valvular calcification and to identify its targets in the pathogenesis. Experimental Approach: Effects of H2S on osteoblastic transdifferentiation of valvular interstitial cells (VIC) isolated from samples of human aortic valves were studied using immunohistochemistry and western blots. We also assessed H2S on valvular calcification in apolipoprotein E-deficient (ApoE−/−) mice. Key Results: In human VIC, H2S from donor compounds (NaSH, Na2S, GYY4137, AP67, and AP72) inhibited mineralization/osteoblastic transdifferentiation, dose-dependently in response to phosphate. Accumulation of calcium in the extracellular matrix and expression of osteocalcin and alkaline phosphatase was also inhibited. RUNX2 was not translocated to the nucleus and phosphate uptake was decreased. Pyrophosphate generation was increased via up-regulating ENPP2 and ANK1. Lowering endogenous production of H2S by concomitant silencing of cystathionine γ-lyase (CSE) and cystathionine β-synthase (CBS) favoured VIC calcification. analysis of human specimens revealed higher Expression of CSE in aorta stenosis valves with calcification (AS) was higher than in valves of aortic insufficiency (AI). In contrast, tissue H2S generation was lower in AS valves compared to AI valves. Valvular calcification in ApoE−/− mice on a high-fat diet was inhibited by H2S. Conclusions and Implications: The endogenous CSE-CBS/H2S system exerts anti-calcification effects in heart valves providing a novel therapeutic approach to prevent hardening of valves