Antioxidant gene expression in the blood‐feeding fly Glossina morsitans morsitans

Abstract

We report the characterization of 11 antioxidant genes from the tsetse fly Glossina m. morsitans. Through similarity searches which detected homology we suggest that these genes consist of two superoxide dismutases (one with a putative signal peptide), three thioredoxin peroxidases (one with a putative signal peptide), three peroxiredoxins, one further signal peptide-containing peroxidase with its closest similarity to a glutathione peroxidase, one catalase and one thioredoxin reductase. We describe the changes occurring in the expression levels of these genes during fly development, in different adult tissues, in the adult midgut through the digestive cycle and following trypanosome infection. Overall, nine of the 11 genes studied showed responses to changes in physiological circumstance, with the peroxiredoxin group showing the smallest variations throughout.

Antioxidant defense response in a galling insect

“…This is similar to the patterns described for Spodoptera littoralis (27), G. morsitans (7), and Aulocara ellioti (2). In S. littoralis and A. ellioti high levels of SOD and CAT activity occur in the midgut contents and/or midgut tissues (2,27), whereas the G. morsitans GPX-like gene (GTP0092) showed greatest expression in the midgut compared with fat body and flight muscle tissues (7).…”

“…In particular, the deduced amino acid sequences of both Hessian fly PHGPX genes revealed the presence of a nonselenium cysteine residue in the active pocket of the protein, thus classifying these enzymes as selenium-independent forms of PHGPX, or cys-PHGPX. The C47 of MdesPHGPX-1 and C44 of MdesPHGPX-2 are assumed to be the active catalytic residue in all cys-PHGPX enzymes reported thus far (5)(6)(7)(8)25). Furthermore, phylogenetic analyses grouped the PHGPXs, including the Hessian fly PHGPXs, separate from other forms of GPXs.…”

“…According to Behne and Kyriakopoulos (4), the mammalian GPX enzymes, which have selenium associated with the active cysteine (selenium-dependent), can be grouped into five forms: the classical or cytosolic GPX, gastrointestinal GPX, plasma GPX, phospholipid hydroperoxide GPX (PHGPX), and sperm nuclei GPX. However, PHGPXs reported in nematodes (5), endoparasitoids (6), insects (7), and plants (8) encode seleniumindependent forms. In particular, the PHGPX forms reduce phospholipid and cholesterol hydroperoxides and thereby play an important role in protecting biological membranes against oxygen toxicity.…”

Proteome changes in the plasma of Papilio xuthus (Lepidoptera: Papilionidae): effect of parasitization by the endoparasitic wasp Pteromalus puparum (Hymenoptera: Pteromalidae)

“…Two proteins belonging to peroxidases, thiol peroxiredoxin (Tpx) (spot 8) and peroxiredoxin (Prx) 1 (spot 10), were identified as strongly induced after parasitization in this work. Tpx is known to eliminate H 2 O 2 and alkyl hydroperoxidases with the use of a thiolreducing equivalent (Munks et al, 2005). The antioxidant activity of Prx is due to a reduction of hydroperoxide, with thioredoxin as an immediate hydrogen donor (Rodriguez et al, 2000).…”

Nutritional stress of adult female tsetse flies (Diptera: Glossinidae) affects the susceptibility of their offspring to trypanosomal infections

“…Other factors that are induced by starvation and that may affect the development of a trypanosomal infection in tsetse can, however, not be excluded. They include midgut lectins, anti-oxidants and symbiotic associations in tsetse (Abubakar et al, 2006;Munks et al, 2005;Macleod et al, 2007;Roditi and Lehane, 2008). Although these observations are based entirely on laboratory experiments, the outcome may contribute to a better understanding of the seasonal dynamics of trypanosomal infection rates in field populations of tsetse flies.…”