Effects of different prey regimes on activities of digestive enzymes in Andrallus spinidens (Hem.: Pentatomidae)

The responses of digestive enzymes of the midgut of Andrallus spinidens Fabricius nymphs, toward feeding on Chilo suppressalis Walker, Galleria melonella (L.), Plodia interpunctella (Hübner) and Ephestia kuehniella Zeller were analyzed to find the most satisfactory species for a mass rearing program. The nymphs were fed from 2nd instar until 24 hours after the emergence of the 5th instar. The highest weight gain was recorded in the nymphs that fed on C. suppressalis and G. melonella, and the highest amount of total protein found in the nymphs feeding on G. mellonella. Carbohydrase activities including α-amylase, α- and β-glucosidase were the highest in the nymphs that were fed on C. suppressalis and E. kuhniella. The highest TAG-lipase activity occurred in the nymphs feeding on G. mellonella and the related gel electrophoresis showed distinctive zones in comparison with the rest. General proteolytic was performed at two pH values and the highest activity recorded in G. melonella (pH 8) and E. kuehniella (pH 6). The highest activities of serine proteinases, cysteine proteinases and two exopeptidases were found in the nymphs fed on G. mellonella and E. kuehniella. Correlation between digestive enzyme activities in A. spinidens and nutritional composition of their feeds may reflect the adaptive nature of the enzymatic profile. These findings can efficiently help to find the most suitable species for an efficient control program and successful mass rearing of the biocontrol agent

Efficacy of essential oil of Lavandula angustifolia on mortality and physiological parameters of diamondback moth, Plutella xylustella (Lep.: Pyralidae)

Efficacy of the essential oil of the plant species Lavandula angustifolia on the mortality, physiology and biochemistry of diamondback moth, Plutella xylustella L., was studied under laboratory conditions (24 ± 2ºC, 75 ± 5% R.H. and 16 L: 8 D hours). The LC10, LC30 and LC50 values of the essential oil were estimated as 0.0857%, 0.270% and 0.599% (V/V), respectively. The repellency effect for the LC10 and LC30 concentrations on third instar larvae were 19.2 ± 3.61 and 34.29 ± 4.87, respectively. The approximate digestibility (AD), efficiency of conversion of ingested food (ECI), efficiency of conversion of digested food (ECD), relative growth rate (RGR) and relative consumption rate (RCR) for the treated larvae in three days showed significant differences compared with the controls. The effectiveness of plant essential oils on digestive enzymes, total protein, triglycerides, alkaline phosphatase, protease, lipase, alfa amylase, glutathione S-transferase and esterase were also significantly different. Our finding suggests that the essential oil of L. angustifolia can be efficiently used as a botanical insecticide

An Evolutionary Trade-Off between Protein Turnover Rate and Protein Aggregation Favors a Higher Aggregation Propensity in Fast Degrading Proteins

We previously showed the existence of selective pressure against protein aggregation by the enrichment of aggregation-opposing ‘gatekeeper’ residues at strategic places along the sequence of proteins. Here we analyzed the relationship between protein lifetime and protein aggregation by combining experimentally determined turnover rates, expression data, structural data and chaperone interaction data on a set of more than 500 proteins. We find that selective pressure on protein sequences against aggregation is not homogeneous but that short-living proteins on average have a higher aggregation propensity and fewer chaperone interactions than long-living proteins. We also find that short-living proteins are more often associated to deposition diseases. These findings suggest that the efficient degradation of high-turnover proteins is sufficient to preclude aggregation, but also that factors that inhibit proteasomal activity, such as physiological ageing, will primarily affect the aggregation of short-living proteins

Exposure to Sublethal Doses of Fipronil and Thiacloprid Highly Increases Mortality of Honeybees Previously Infected by Nosema ceranae

International audienceBACKGROUND: The honeybee, Apis mellifera, is undergoing a worldwide decline whose origin is still in debate. Studies performed for twenty years suggest that this decline may involve both infectious diseases and exposure to pesticides. Joint action of pathogens and chemicals are known to threaten several organisms but the combined effects of these stressors were poorly investigated in honeybees. Our study was designed to explore the effect of Nosema ceranae infection on honeybee sensitivity to sublethal doses of the insecticides fipronil and thiacloprid. METHODOLOGY/FINDING: Five days after their emergence, honeybees were divided in 6 experimental groups: (i) uninfected controls, (ii) infected with N. ceranae, (iii) uninfected and exposed to fipronil, (iv) uninfected and exposed to thiacloprid, (v) infected with N. ceranae and exposed 10 days post-infection (p.i.) to fipronil, and (vi) infected with N. ceranae and exposed 10 days p.i. to thiacloprid. Honeybee mortality and insecticide consumption were analyzed daily and the intestinal spore content was evaluated 20 days after infection. A significant increase in honeybee mortality was observed when N. ceranae-infected honeybees were exposed to sublethal doses of insecticides. Surprisingly, exposures to fipronil and thiacloprid had opposite effects on microsporidian spore production. Analysis of the honeybee detoxification system 10 days p.i. showed that N. ceranae infection induced an increase in glutathione-S-transferase activity in midgut and fat body but not in 7-ethoxycoumarin-O-deethylase activity. CONCLUSIONS/SIGNIFICANCE: After exposure to sublethal doses of fipronil or thiacloprid a higher mortality was observed in N. ceranae-infected honeybees than in uninfected ones. The synergistic effect of N. ceranae and insecticide on honeybee mortality, however, did not appear strongly linked to a decrease of the insect detoxification system. These data support the hypothesis that the combination of the increasing prevalence of N. ceranae with high pesticide content in beehives may contribute to colony depopulation

Digestive proteolytic activity in Apodiphus amygdali Germar (Hemiptera: Pentatomidae): effect of endogenous inhibitors

The digestive proteolytic profile of Apodiphus amygdali was determined by using several substrates and specific inhibitors. Analysis of optimal pH and temperature showed the highest enzymatic activity at the pH range of 6-7 and temperature of 40°C when azocasein was used as a substrate. By using a negative control, the presence of several specific proteases were determined including tryspin-like, chymotrypsinlike, elastase, cathepsin B, cathepsin L, amino- and carboxypeptidases in the midgut content of A. amygdali, with the highest and the lowest activities of cathepsin L and carboxypeptidase, respectively. pH dependency of specific proteases revealed optimal pHs of 9, 8 and 9 for trypsin-, chymotrypsin-like, 6 for cathepsins and 5-6 for carboxy- and aminopeptidases, respectively. Specific inhibitors, including phenylmethylsulfonyl fluoride, Na-p-tosyl-L-lysine chloromethyl ketone, Ntosyl- L-phenylalanine chloromethyl ketone, L-trans-epoxysuccinylleucylamido-(4-guanidino)-butane, phenanthroline and ethylendiamidetetraacetic acid, significantly decreased proteolytic activity, indicating the presence of different proteases in the midgut of A. amygdali. Extracted inhibitors from the midgut demonstrated significant inhibition of specific proteolytic activities of A. amygdali except for cathepsin B and aminopeptidase. The results indicated that determination of digestive proteolytic activity could be helpful to clarify digestion process in insects. Moreover, understanding the nature of digestive proteases might be used to develop several inhibitors for providing resistant crop varieties against pests

Lipase and invertase activities in midgut and salivary glands of Chilo suppressalis (Walker) (Lepidoptera, Pyralidae), rice striped stem borer

The rice striped stem borer, Chilo supprressalis, was introduced to Iran in 1973 where it is now widely distributed and causes severe damages. Lipases, which catalyses the hydrolysis of fatty acid ester bonds, are widely distributed among animals, plants and microorganisms. Invertases (β-fructofuranosidase) are glycosidehydrolases that catalyze the cleavage of sucrose (β-D-glucopyranosyl-S-D-fructofuranoside) into the monosaccharides glucose and fructose. Laboratory-reared 4th instar larvae were randomly selected, their midgut and salivary glands were removed by dissection under a light microscope and lipase and invertase activities were assayed. The activity of lipase/invertase in the midgut and salivary gland were 0.49/0.27 and 0.35/0.23 μmol/min/mg protein, respectively. The optimum pH and temperature for both the two enzymes were determined to be 10-11 and 37-40 °C, which is consistent with pH and temperature values already observed in Lepidoptera. The enzyme activity was reduced by addition of NaCl, KCl, MgCl2, SDS, urea and plant extracts from Artemisia annua, but not by CaCl2 which enhanced enzyme activity. Pest control with usage of resistant varieties of plants is one of the most important practices that are dependant on inhibitors already present in nature. Hence, characterization of insect digestive enzymes, especially examination of inhibition effects on enzyme activity, could be useful in developing new strategies for pest control

Production and characterization of egg yolk antibody (IgY) against recombinant VP8 - S2 antigen

Bovine Rotavirus and Bovine Coronavirus are the most important causes of diarrhea in newborn calves and in some other species such as pigs and sheep. VP8 subunit of rotavirus is the major determinant of the viral infectivity and neutralization. Spike glycoprotein of coronavirus is responsible for induction of neutralizing antibody response. Studies showed that immunoglobulin of egg yolk (IgY) from immunized hens has been identified to be a convenient source for specific antibodies for using in immunotherapy and immunodiagnostic to limit the infections. In this study, chimeric VP8-S2 gene was designed using by computational techniques. The chimeric VP8-S2 gene was cloned and sub-cloned into pGH and pET32a (+) vectors. Then, recombinant pET32a-VP8-S2 vector was transferred into E. coli BL21 CodonPlus (DE3). The expressed protein was purified by Ni-NTA chromatography column. Hens were immunized with the purified VP8-S2 protein three times. IgY was purified from egg yolks using polyethylene glycol precipitation method. Activity and specificity of anti-VP8-S2 IgY were detected by dot-blotting, Western-blotting and indirect ELISA. We obtained anti-VP8-S2 IgY by immunizing hens with the recombinant VP8-S2 protein. The anti-VP8-S2 IgY was showed to bind specifically to the chimeric VP8-S2 protein by dot-blotting, Western-blotting analyses and indirect ELISA. The result of this study indicated that such construction can be useful to investigate as candidates for development of detection methods for simultaneous diagnosis of both infections. Specific IgY against the recombinant VP8-S2 could be recommended as a candidate for passive immunization against bovine rotavirus and bovine coronavirus

Ethnomedicinal uses, phytochemistry and pharmacology of different Cichorium species (Asteraceae) : a review

Cichorium species have been used widely in traditional medicine universally. It is reported as a treatment for various respiratory and gastrointestinal disorders, as well as diabetes and rheumatism. A range of constituents including phenolic and poly phenolic compounds, fatty and organic acids and essential oils comprise the chemical composition of Cichorium species. Furthermore, modern investigations on these species has shown different pharmacological activities such as antioxidant, antiproliferative, anti-inflammation, antibacterial, anti-hyperglycemic, antidiabetic and hepatoprotective effects which are associated with divers molecular pathways and mechanisms. In this chapter, we have summarized comprehensive information regarding traditional and ethnomedicinal uses, phytochemical analysis and pharmacological aspects of Cichorium species