Chemosensory proteins of Locusta migratoria

Abstract

Two different classes of chemosensory proteins (CSPs) in Locusta migratoria have been identified on the basis of the molecular cloning of a series of different cDNAs from the antennae of this insect. Several CSP isoforms have been purified and biochemically characterized from antennal and wing extracts, some of them corresponding to expression products predicted for the identified cDNAs. In wings, the nature of the main endogenous ligand binding to these proteins was determined as oleoamide by a gas chromatography-mass spectrometric approach. One of these isoforms has been expressed in a bacterial system with high yield and used in a fluorescent binding assay. Competitive binding experiments have indicated the presence of long-chain compounds among the best ligands.

Cooperative interactions between odorant-binding proteins of Anopheles gambiae

“…As observed with most insect OBPs, our recombinant proteins were present in the bacterial cells as insoluble inclusion bodies and had to be solubilised by denaturation and reduction. Although the conditions used in this process are particularly harsh, the unfolded OBPs can be renatured correctly as demonstrated in several cases by binding experiments, pairing of disulphide bridges and crystal structure [27,36,37]. OBP47, despite its length and the presence of 13 cysteine residues, was refolded into its active conformation as judged from its binding properties toward several ligands similar to those of other insect OBPs.…”

“…After further centrifugation, OBPs, present in the pellets (from 1 of culture) as inclusion bodies were solubilised by dissolving the pellet in 10 ml of 8 M urea, 1 mM DTT in 50 mM Tris buffer, pH 7.4, then diluting to 100 ml with Tris buffer and dialysing three times against Tris buffer. The OBPs were then purified using combinations of chromatographic steps anion-exchange resins, such as DE-52 (Whatman), QFF or Mono-Q (GE Healthcare), followed by gel filtration on Sephacryl-100 or Superose-12 (GE Healthcare) along with standard protocols previously adopted for other OBPs [27,28].…”

New isoforms of odorant‐binding proteins and potential semiochemicals of locusts

“…However, in the antenna and other sensory organs OBPs and CSPs are abundantly expressed. Although at least 20 different CSPs have been reported in locusts (Angeli et al, 1999;Picimbon et al, 2000;Ban et al, 2003b), a single OBP was identified, present in two isoforms differing by a single amino acid substitution (Ban et al, 2003a).…”

Deterrent activity of plant lectins on cowpea weevil Callosobruchus maculatus (F.) oviposition

“…It is well documented that the insect's sensory mechanisms are very important for behavior regulation of survival and reproduction, including location of food resources, selection of mates and determination of oviposition sites (Hekmat-Scafe et al, 2002;Ban et al, 2003). Messina et al (1987a,b) reported that the maxillary and labial palpi of C. maculatus are the main organs used in host discrimination and egg-spacing behavior.…”