No abstract

In the current study, the entomotoxic effects of a lectin, extracted from Polygonum persicaria, were determined on Pieris brassicae larvae. The purified molecule significantly decreased larval survival, weight, and mass protein. Different concentrations of P. persicaria agglutinin (PPA) (0.5, 1 and 2 mg/ml) significantly decreased nutritional indices including: the efficiency of conversion of ingested food (ECI), the efficiency of conversion of digested food (ECD), and approximate digestibility (AD) in a dose-dependent manner. There was a significant decrease in larval α-amylase activity after larval fed on PPA. The decreased activity was found in both the biochemical assessment and gel electrophoresis; sharpness of one isozyme decreased and another completely disappeared. Meanwhile, PPA significantly decreased activities of glucosidases mainly β-glucosidase. Fed of P. brassicae larvae on different concentrations of PPA, significantly decreased activity of TAG-lipase in both the biochemical assessment and gel electrophoresis. It was found that alkaline phosphatase (ALP) and acid phosphatase (ACP) were also affected by PPA but concentrations of 1 and 2 mg/ml showed statistical differences compared to the control. General and specific proteolytic activities statistically decreased after larvae fed on different concentrations of PPA. Results of our study could bring attention to this molecule, showing it to be a safe and efficient control of the pest worldwide.

The transcription factor Ftz‐f1 has multiple functions in insect development in a spatial‐temporal line. One of these roles is in the insect ovaries, specifically in the regulation of steroidogenic enzymes production. We studied the function of F in Blattella germanica oogenesis, as it shows two moments of high expression in ovaries: before the imaginal moult, and just before ovulation in the adult. Injecting dsftz‐f1 into adult females, either just after the imaginal moult or just prior to choriogenesis, prevented oviposition, with differences between the two approaches. In 3‐day‐old adult females treated with dsftz‐f1 just after the emergence, the expression of ftz‐f1 was not modified, but the steroidogenic genes increased their expression. ftz‐f1 transcript levels in the ovaries of 5‐day‐old dsftz‐f1‐treated females were significantly depleted, and the expression levels of the same steroidogenic genes began to decrease. These results suggest that Ftz‐f1 regulates the expression of steroidogenic genes in B. germanica, with phm possibly being a key target. Ftz‐f1 has a different temporal function in the cytoskeleton of follicular cells of the basal ovarian follicles. Early in the gonadotrophic cycle, Ftz‐f1 promotes the expression of genes related to the cytoskeleton and muscle proteins, while at the end of the cycle it maintains the expression levels of these genes, thus ensuring correct ovulation.

Lectins are widespread proteins found in plants, fungi, bacteria, and vertebrates, and they play the critical roles in many physiological functions. Two lectin molecules (namely, RSAI and RSAII) were extracted fromRhizoctonia solaniKuhn and their effects onPieris brassicaeL. larvae were determined by larval survival rate, body mass, nutritional indices, digestive enzyme activities, andcaspase-3gene expression. The highest mortality caused by RSA treatment was recorded up to 80%, the larval weight decreased to 0.05 g and Similarly, RSAs significantly decreased nutritional indices including conversion efficiency of ingested food (ECI), conversion efficiency of digested food (ECD), approximate digestibility (AD), relative consumption rate (RCR), and relative growth rate (RGR) in a dose-dependent manner. Activities of α-amylase and α- and β-glucosidases significantly decreased in the larvae fed with RSA-treated diets. Also, activities of TAG-lipase and proteases significantly reduced after feeding with different concentrations of RSAs. Gene expression analysis ofcaspase-3in control and treated larvae revealed significant increment of its expression in the larvae fed with RSAI and RSAII, respectively, 9.52- and 1.47-fold compared to control. These results clearly demonstrated insecticidal effects ofR. solanilectins onP. brassicaevia several physiological pathways, thus rendering RSA as a good target for furthering our knowledge and suggesting new strategies to overcome pesticide side effects.