The importance of starch and sucrose digestion in nutritive biology of synanthropic acaridid mites: α‐Amylases and α‐glucosidases are suitable targets for inhibitor‐based strategies of mite control

Abstract

The adaptation of nine species of mites that infest stored products for starch utilization was tested by (1) enzymatic analysis using feces and whole mite extracts, (2) biotests, and (3) inhibition experiments. Acarus siro, Aleuroglyphus ovatus, and Tyroborus lini were associated with the starch-type substrates and maltose, with higher enzymatic activities observed in whole mite extracts. Lepidoglyphus destructor was associated with the same substrates but had higher activities in feces. Dermatophagoides farinae, Chortoglyphus arcuatus, and Caloglyphus redickorzevi were associated with sucrose. Tyrophagus putrescentiae and Carpoglyphus lactis had low or intermediate enzymatic activity on the tested substrates. Biotests on starch additive diets showed accelerated growth of species associated with the starch-type substrates. The inhibitor acarbose suppressed starch hydrolysis and growth of the mites. We suggest that the species with higher starch hydrolytic activity in feces were more tolerant to acarbose, and alpha-amylase and alpha-glucosidase of synanthropic mites are suitable targets for inhibitor-based strategies of mite control.

Comparative analyses of proteolytic activities in seven species of synanthropic acaridid mites

“…A similar situation was observed for bacteriolytic and starch-degrading activities (Erban and Hubert, 2008;Erban et al, 2009). This means that many L. destructor gut enzymes are produced in very large amounts in comparison with the rest of the mite species studied.…”

“…Some influences of protein addition into the diets were observed in T. putrescentiae and A. siro, which showed only intermediate protease activities, but the effect on population increase was very low. A similar small effect on population increase was observed on the addition of starch into diets (Erban et al, 2009). The results showed that the nutritional benefit from bacterial cells was higher than from pure proteins (Erban and Hubert, 2008).…”

“…A precision of 0.25 pH units was used in the digestive pH region of mites from pH 4 to 5.5 (Erban et al, 2009). Azocasein, the most commonly used chromogenic substrate, was used as a substrate for screening general protease activity (Cat.…”

“…The solutions were properly mixed using an MS1 Minishaker (IKA s ; Staufen, Germany) and were then lyophilized in a PowerDry LL3000 (Thermo). The lyophilized material was ground into a powder in a pottery grinding mortar and the material was rehydrated for 24 hr before the experiment in a desiccator containing distilled water (Erban et al, 2009). Fifty milligrams of each diet was placed in the rearing chambers with 10 adult mites (eight females and two males specifically for D. farinae and T. lini, only) and incubated in desiccators in the dark at 2570.51C and 85% relative humidity for 21 days.…”

Visualization of protein digestion in the midgut of the acarid mite Lepidoglyphus destructor

“…The use of chromogenic substrates for the visualization of digestive processes has been tested previously using starch azure and Micrococcus lysodeikticus for the localization of a-amylase and bacteriolytic activity in mites, respectively (Erban and Hubert, 2008;Erban et al, 2009). Recently, the digestive activity of proteases in the (B) a specimen fed the ZRRpNA (P138) chromogenic substrate; the empty arrows point to the yellow color in the colon and postcolon, and the black arrows point to mesenteric cells containing substrate inside granulae; (C) total view of specimens fed the cathepsin H (A2027) fluorescent substrate; the arrows point to areas with high concentrations of fluorescent markers; (D) specimens fed the ArgpNA (P136) chromogenic substrate; the empty arrows point to the yellow color in the colon and postcolon; the black arrows point to mesenteric cells containing substrate inside granulae; (E, F) specimens fed the cathepsin D (C6983) fluorescent substrate; (E) total view, with arrows pointing to areas with high concentrations of fluorescent marker; (F) detailed view of the mesodeum, with arrows pointing to areas with high concentrations of fluorescent markers in food boli in the colon and in the postcolon; (G, H) specimens fed MAAPMpNA, indicating cathepsin G activity; (G) total view; (H) detailed view, with black arrows pointing to mesenteric cells that contain substrate inside of granulae.…”