Search

Start Over Subject neuropeptides

1. Presence of [His7]- corazonin in the central nervous system of a newly isolated albino strain of Schistocerca gregaria (Orthoptera: Acrididae) - mass spectrometric and immunocytochemical evidence

Creator:
Rahman, Mazibur M., Baggerman, Geert, Schoofs, Liliane, de Loof, Arnold, and Breuer, Michael
Type:
article, model:article, and TEXT
Subject:
Albinism, locusts, Schistocerca gregaria, [His7]-corazonin, neuropeptides, mass spectrometry, and immunocytochemistry
Language:
English
Description:
An inbred strain of a newly isolated spontaneous albino mutant of Schistocerca gregaria (Forsk.) was examined for the presence of the neuropeptide [His7]-corazonin by immunocytochemical and mass spectrometric methods. It was concluded that this peptide is definitely present in a limited number of neurosecretory cells in the pars lateralis as well as in the corpora cardiaca (CC). Injection of either synthetic [His7]-corazonin or of extracts of CC of the normal coloured phenotype of S. gregaria failed to induce darkening of the cuticle, while albino Locusta migratoria, used as a positive control, turned dark. The conclusion is that the cause of albinism in the new S. gregaria albino is probably due to a defect in the receptor system for [His7]-corazonin or in the biosynthetic pathway of melanin.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

2. Structure-activity relationships of insect neuropeptides of the pyrokinin/PBAN family and selective action on pupariation in fleshfly (Neobelleria bullata) larvae (Diptera: Sarcophagidae)

Creator:
Žďárek, Jan, Nachman, Ronald J., and Hyes, Timothy K.
Type:
article, model:article, and TEXT
Subject:
puparium formation, fleshfly, Neobelleria bullata pupariation factors, neuropeptides, pyrokinins, and pyrokinin/PBAN family
Language:
English
Description:
Screening for puparium formation accelerating activity of neuropeptides and/or analogues belonging to 14 different peptide families revealed the strong activity of members and analogues of the pyrokinin/PBAN (pheromone biosynthesis activating neurohormone) family that all share the common C-terminal sequence, FXPRLamide (X = V, T, S, or G). Both pupariation behaviour and cuticular tanning can be accelerated by a C-terminal pentapeptide fragment composed of only the FTPRLamide sequence. Truncation of the C-terminal sequence to the tetrapeptide TPRLa did not diminish either aspect of the activity. Markedly reduced, but still significant, activity was observed after further truncation to the pyrokinin C-terminal tripeptide. The RLa terminal fragment showed no activity. Thus the C-terminal tripeptide appears to be the active core for pupariation acceleration. The core sequence for a maximum response is the C-terminal tetrapeptide TPRLa. This represents a major difference from the activity profile observed in other pyrokinin assays, in which the C-terminal pentapeptide is required. The C-terminal amide group is also of great importance to pupariation acceleration activity, as LPK acid induces a large drop in threshold activity. Periviscerokinin-2 contains a C-terminal tripeptide sequence (PRVamide) that is quite similar to the pyrokinin C-terminal tripeptide PRLamide and, accordingly, elicits a lower level pupariation acceleration activity. The locust pyrokinin Lom-MT-TV preferentially promotes acceleration of the behavioural over the tanning aspects of pupariation and can therefore, in large measure, provide a means of separating the two aspects. Ligation experiments demonstrated that the effect of the LPK analogues on pupariation behaviour is likely mediated through the CNS, while the action on cuticular tanning is of a peripheral nature.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public