A novel homologue of insect defensin designated lucifensin (Lucilia defensin) was purified from the extracts of various tissues (gut, salivary glands, fat body, haemolymph) of green bottle fly (Lucilia sericata) larvae and from their excretions/secretions. The primary sequence of this peptide of 40 residues and three intramolecular disulfide bridges was determined by ESI-QTOF mass spectrometry and Edman degradation and is very similar to that of sapecin and other dipteran defensins. We assume that lucifensin is the key antimicrobial component that protects the maggots when they are exposed to the highly infectious environment of a wound during the medicinal process known as maggot therapy. We also believe that lucifensin is that long-sought larger molecular weight antimicrobial factor of the Lucilia sericata excretions/secretions believed to be effective against pathogenic elements of the wound microbial flora.
The post‐hibernating adults of the apple blossom weevil, Anthonomus pomorum (L.), show preferences for certain cultivars in mixed apple tree orchards. The degree of infestation of various cultivars was positively correlated with the density of flower buds at a comparable phenological stage, but the numbers of collected beetles were not linearly proportional to the bud density of different cultivars. Hence other possible factors, namely chemical ones, were investigated. Chromatographic analysis of apple tree bud emanations showed that volatiles from two different apple cultivars that show a different attractiveness to the beetles, differed in chemical composition. Several less volatile components of the bud emanation bouquet elicited antennographic responses in both male and female antennae. Four terpene hydrocarbons, namely 3‐carene, perillene, caryophyllene and (E,E)‐α‐farnesene, were identified among the components that produced distinct electrophysiological responses in the antennae. These findings support a hypothesis that the adult weevils use chemical cues for olfactory discrimination during host‐searching behaviour.
The mechanism of puparium formation in the fleshfly Sarcophaga bullata Parker was studied. Several distinct morphological events take place during the hour prior to the completion of the white puparium. 1. The anterior three larval segments are irreversibly retracted. 2. The body contracts by muscular action to about two-thirds of its original length. 3. Simultaneously a longitudinal shrinkage occurs in the cuticle, giving it a smooth surface. 4. Finally the cuticle becomes stabilized in the sense that it can no longer be stretched, and no longer collapses upon release of internal pressure by bleeding. 5. Tanning starts almost as soon as the smooth barrel shape of the puparium is completed. The following observations demonstrate the largely independent nature of these processes: 1 . Paralyzing the musculature, by ligation, tetrodotoxin, or bee venom, leads to tanned puparia in the shape of the larva. 2. Disabling the shrinkage system (e.g., by ryanodine or eserine) leads to puparia with a deeply folded surface. 3. Injecting smaller doses of tetrodotoxin or bee venom leads to elongated puparia with a shrunken (smooth) surface. 4. Injecting a certain ecdysone analogue leads to a puparium which is normal except for the failure of the anterior end to retract. 5. Release of internal pressure by bleeding leads to puparia which are supercontracted and folded. 6. Injection of a tanning inhibitor (a-MDH) leads to a .white puparium of normal shape which fails to tan. The transformation of the larval cuticle into the tanned puparium is accompanied by a spectacular water loss i n the cuticle which is particularly rapid during the brief period between completion of the white puparium and start of tanning. This water loss is almost certainly correlated with the above mentioned stabilization of the puparium.
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