Evaluation of analogs of the blocked insect myotropic neuropeptide leucopyrokinin (LPK) has demonstrated its relative insensitivity to amino acid substitution in the N-terminal in contrast to the ...C-terminal region. Truncated analogs of LPK without the first, second, and third N-terminal amino acids retain a significant 144%, 59% and 30% of the activity of the parent octapeptide, respectively. The 2-8LPK analog is the first fragment of an insect neuropeptide to exhibit greater activity than the parent hormone. In contrast, truncated analogs of the insect myotropic, proctolin, exhibit little or no activity. The pentapeptide fragment Phe-Thr-Pro-Arg-Leu-NH2 has been identified as the active core of LPK.
A sulfated neuropeptide pGlu-Ser-Asp-Asp-Tyr(SO3H)-Gly-His-Met-Arg-Phe-NH2, with a blocked N-terminus and related to the undecapeptide leucosulfakinin, has been isolated from head extracts of the ...cockroach, Leucophaea maderae. It exhibits sequence homology with the hormonally-active portion of vertebrate hormones cholecystokinin, human gastrin II and caerulin. This peptide, termed leucosulfakinin-II, shares a common C-terminal heptapeptide fragment with leucosulfakinin and a comparison of the two sequences provides an assessment of the importance of the constituent amino acids to biological activity. Leucosulfakinin-II shows a greater resemblance to cholecystokinin than does leucosulfakinin. Leucosulfakinin-II and leucosulfakinin are the only two reported invertebrate sulfated neuropeptides. As with leucosulfakinin, the intestinal myotropic activity of leucosulfakinin-II is analogous to that of gastrin and cholecystokinin. The sequence homology between the leucosulfakinins and the vertebrate hormones, as well as their analogous myotropic activity, suggest that gastrin/cholecystokinin-like neuropeptides are not confined to vertebrates, but also occur in invertebrates.
The fumigant toxicity of 28 essential oils extracted from various spice and herb plants and some of their major constituents were assessed for adult coleopterans Rhyzopertha dominica, Oryzaephilus ...surinamensis, Tribolium castaneum, and Sitophilus oryzae. Three groups of active materials were distinguished: (1) The compounds terpinen 4-ol, 1,8-cineole, and the essential oils of three-lobed sage, sage, bay laurel, rosemary, and lavender were most active against R. dominica; (2) The compounds linalool, alpha-terpineol, and carvacrol and the essential oils of oregano, basil, Syrian marjoram, and thyme were most active against O. surinamensis; and (3) the compound 1,8-cineole and the essential oils anise and peppermint were active against T. castaneum
The effect of the hypoestrogenic state, induced by a GnRH agonist (GnRH-a), on cardiac function in healthy young women, was evaluated by Doppler echocardiography performed before treatment and when ...serum 17 beta-estradiol levels were suppressed by GnRH-a to 36.7 pmol/L. The following parameters of aortic flow were measured: peak flow velocity, ejection time, and acceleration time. Additional parameters calculated were flow velocity integral, cardiac index, and mean acceleration. The study group included 15 menstruating women, aged 25-42 yr (mean, 33 yr), with symptomatic fibroids, endometriosis, or scheduled for in vitro fertilization, who were treated with a GnRH-a. There were significant decreases in peak flow velocity (99 +/- 11 vs. 86 +/- 11 cm/s; P = 0.0004) and cardiac index (3.0 +/- 0.7 vs. 2.5 +/- 0.5 L/min.m2; P = 0.002). A decrease that did not reach statistical significance was noted in flow velocity integral (18.9 +/- 2.7 vs. 16.5 +/- 3.4 cm; P = 0.07). Mean acceleration was decreased significantly (12.6 +/- 2.6 vs. 10.8 +/- 1.8 m/s.s; P = 0.01), but no significant changes in acceleration time (81 +/- 16 vs. 83 +/- 10 ms; P = 0.7) or ejection time (296 +/- 25 vs. 295 +/- 27 ms; P = 0.8) were observed. These results indicate that estrogen deprivation is associated with smaller stroke volume and flow acceleration and might suggest that hypoestrogenism has a direct effect on cardiovascular performance.
