6A) Considering the presence of digestive enzymes capable of dig

6A). Considering the presence of digestive enzymes capable of digesting bacterial and fungal cell walls, and larval actively feeding on mycelia, we decided to test if sandfly larvae accepted to ingest a number of selected microorganisms. Different species of bacteria Talazoparib cost and the yeast S. cerevisiae were labeled with the fluorescent stain FITC and offered to 4th instar larvae, mixed with non-supplemented larval food. Larval food was offered in excess so the larvae were not starved. After overnight maintenance under those

conditions, fluorescence coherent with ingestion of S. cerevisiae, E. coli, S. xylosus and S. marcescens could be observed in a fluorescence microscope in the midgut contents ( Fig. 6B–D). Larva controls were fed with regular food and treated in the same way but did not show any fluorescent particles (data not shown). The determination of some carbohydrase activities in larval midguts of L. longipalpis and its food revealed that carbohydrase activities present in an amount of food with identical mass of a larval midgut are, in most cases, at least ten times higher than those obtained from one insect, with the sole exceptions of α-glucosidase and sialidase. Even enzymes putatively involved in the initial digestion of microorganism cell walls, such as β-1,3-glucanase, chitinase or lyzozyme, are more active

in food than in the larval midgut. In other detritus-feeding insects such ifoxetine as Periplaneta americana and Tenebrio molitor, selleck chemical the activity of these enzymes has already been compared with food activities ( Genta et al., 2003 and Genta

et al., 2009), with higher activities in the insect midgut. However, in these cases the food was artificial or was a commercial diet, with low prevalence of microorganisms. In the case of L. longipalpis, laboratory larvae are grown in a rotten material rich in bacteria and fungi ( Volf and Volfova, 2011), which are known producers of high amounts of all the activities tested. The use of enzymes from food in insect digestion is a well-documented phenomenon, occurring in termites, siricid woodwasps, cerambycid beetles and attine ants (Martin, 1987). In spite of that, attempts to correlate digestion in detritivore insects with food enzymes have failed (Martin, 1987). However, due to the high activities present in L. longipalpis larval food, and the lack of data concerning digestion in sandfly larvae, we decided to investigate if larval carbohydrases in this insect are acquired enzymes. This should permit a better comprehension of larval digestive physiology, and will lay the grounds for future studies on sandfly larval digestive enzymes. The presence of high specific activity of several glycosidases in the midgut tissue reinforces the larval origin of these enzymes.

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