Larval Manduca prothoracic gland cells in vitro responded to prothoracicotropic hormone (PTTH) from neurosecretory cells of the brain with an increase of intracellular free calcium. This effect is reversible and dose-dependent. Preincubation of the glands with TMB-8 and dantrolene, which inhibit the release of calcium from intracellular stores, did not decrease the PTTH-stimulated increase in calcium, indicating that intracellular calcium stores are not involved in the control of ecdysteroidogenesis. Pharmacological studies of the PTTH effect with calcium channel blockers revealed that the increase in calcium was totally blocked by cadmium, partially inhibited by nickel and lanthanum and by amiloride, an antagonist of T-type calcium channels. All other inhibitors tested were ineffective, suggesting that the increase in cytosolic calcium is induced by opening of calcium channels, presumably of the T-type, in response to PTTH. The action of PTTH on these channels may be mediated by a G-protein as shown by the effect of mastoparan, a G-protein activator, which increased the concentration of cytosolic calcium comparable to that evoked by PTTH., Heiner Birkenbeil, and Lit
Autor se pokusil o dílčí komentář k osmisvazkovému projektu Archeologie pravěkých Čech, a to z pozice aktivního účastníka přípravy syntéz pravěku Čech z roku 1978 i 2007–2008. Nová syntéza uspokojivě shrnuje výsledky českého terénního výzkumu i stav zpracování pramenů, ale – podle názoru autora – faktografické limity domácích pramenů spolu s dnešní úrovní integrace výsledků humanitních a přírodních věd omezují možnosti jejich celistvého interpretačního využití. Další rozvoj, resp. přežití oboru bude záviset dílem na míře úspěšnosti integrace českého výzkumu v rámci Evropy, dílem na schopnosti archeologů přesvědčit domácí veřejnost, že péčí a hospodařením s archeologickými prameny plníme nepominutelnou společenskou objednávku nadnárodního dosahu. and The author comments on the eight-volume Archeologie pravěkých Čech [Archaeology of Prehistoric Bohemia] from the position of an active participant in the preparation of the synthesis of information concerning prehistoric Bohemia in 1978 and 2007–2008. This new synthesis provides a satisfactory summary of the results of Czech field research as well as the state of the processing of sources. However, in the opinion of the author, the factographic limits of domestic sources together with today’s unsatisfactory integration of the results of the humanities and natural sciences restricts the possibilities of their cohesive interpretive use. Further progress, or even the survival of the field, will depend in part on the success of the integration of Czech research into the framework of Europe and in part on the ability of archaeologists to convince the public that care and management of archaeological sources is a vital social mission of supranational importance.