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Biomedical subjects

Martin G Edwards

Publications and source records attributed to Martin G Edwards.

4 recordsLinked to original sources

Plant-insect interactions: molecular approaches to insect resistance.

Recent advances in our understanding of induced responses in plants and their regulation, brought about by a revolution in molecular biology, have re-focused attention on the potential exploitation of endogenous resistance mechanisms for crop protection. The future goal of crop biotechnology is thus to engineer a durable, multimechanistic resistance to insect pests through an understanding of the diversity of plant responses to insect attack.

Animals↗

Fusion proteins containing insect-specific toxins as pest control agents: snowdrop lectin delivers fused insecticidal spider venom toxin to insect haemolymph following oral ingestion.

The mannose-specific snowdrop lectin (Galanthus nivalis agglutinin: GNA), when fed to insects, binds to the gut epithelium and passes into the haemolymph. The ability of GNA to act as a carrier protein to deliver an insecticidal spider venom neurotoxin (Segestria florentina toxin 1: SFI1) to the haemolymph of lepidopteran larvae was investigated. Constructs encoding SFI1 and an SFI1/GNA fusion protein were expressed in Pichia pastoris. The insecticidal activity of purified recombinant proteins on injection was found to be comparable to published values for SfI1 purified from spider venom [Toxicon 40 (2002) 125]. Whereas neither GNA nor SFI1 alone showed acute toxicity when fed to larvae of tomato moth (Lacanobia oleracea), feeding SFI1/GNA fusion at 2.5% of dietary proteins was insecticidal to first stadium larvae, causing 100% mortality after 6 days. The protein also showed a significant, dose dependent, toxicity towards fourth and fifth stadium larvae, with growth reduced by up to approximately 90% over a 4-day assay period compared to controls. Delivery of intact SFI1/GNA to the haemolymph in these insects was shown by western blotting; haemolymph samples from fusion-fed larvae contained a GNA-immunoreactive protein of the same molecular weight as the SFI1/GNA fusion. SFI1/GNA and similar fusion proteins offer a novel and effective approach for delivering haemolymph active toxins by oral administration, which could be used in crop protection by expression in transgenic plants.

Animals↗

Motor facilitation following action observation: a behavioural study in prehensile action.

Previous research has shown that the observation of actions and the execution of actions activate common neural systems. More recently, we have presented data showing that action observation of prehension primes subsequent execution (Castiello, Lusher, Mari, Edwards, & Humphreys, 2002). In the current paper we examined action priming under conditions in which the size of the prime did not predict the size of the target (only 20% of trials were valid). We demonstrated reliable priming under these conditions, consistent with the effect occurring automatically. In addition, we show priming even when observers saw just the object rather than the object and a reaching action on the prime trial. We discuss the findings in relation to the role of mirror neurons and object affordances.

Adolescent↗