Both larvae and teratocytes liberated upon hatching from the eggs of the endoparasitoid Cardiochiles nigriceps Viereck were found to release proteins into their surrounding environment as they develop. Teratocytes were found to synthesize and release a number of proteins into culture media in which they were incubated. The proteins released differed among the different teratocyte ages. Larvae were also found to release proteins into the culture media in which they were incubated. Ligation of the head or anal vesicle altered the protein pattern found in the media. The results demonstrate that both larvae and the associated teratocytes release proteins that may have important functions in the parasitoidhost interaction. 0 1994 ~i~e y -~i s s , Inc.Key words: parasitoid, protein secretions, teratocytes, parasitoid larvae INTRODUCTIONInsects, following parasitism by parasitoid Hymenoptera, are either paralyzed or, if they grow and develop, the growth and developmental patterns are often altered. These pathologies, as discussed by Doutt [ 11, are not solely due to the physiological response of the host to the invader, but as discussed by Vinson and Iwantsch [2], are often due to factors released by the parasitoid that alter the physiology of the host in specific ways. Thus, the suitability of an insect to serve as a host for a particular parasitoid depends on constraints that the host represents [3] and the ability of the parasitoid to alter the physiological environment that the host represents. In some situations, and for some host processes, the developing parasitoid must conform to the physiological conditions of the host [4]. In other cases or for other processes in the same host, the parasitoid has evolved mechanisms that alter the host's immediate physiological environment [5-81. Acknowledgments: Approved as TA 30750 by the Director of the Texas Agricultural Experiment Station. Appreciation is extended to Zac Shawhan for insect colony maintenance.Received February 4, 1993; accepted April 6, 1993. 0 1994 Wiley-Liss, Inc. 198Vinson et al.Alteration of the physiological environment within which the parasitoid must develop involves both the injection and release of factors into the host [31. There are two basic sources of these factors. The first group is the parental derived factors that include the poison gland [9-111, calyx region of the lateral oviducts [12,13], the epithelium of the common oviduct [14], or the follicular epithelium [15,161. The second group is the progeny derived factors that include teratocytes and larvae that hatch from the egg [3]. Teratocytes are cells of the embryonic membrane of the parasitoid egg that are released upon hatching into the hemocoel of the host. The developing larvae are also a possible source of host regulatory factors.The larvae of Pimpla turionellae L. and ltoplectis conquisitor Say discharge secretions from their anus [24-271. These secretions have been reported to alter DOPA metabolism, and to have antibacterial and antifungal properties [24,27].Here we examin...

The hypothesis that endogenous short chain fatty acids (C 6-C 10) are important in maintaining seeds of wild oat (Avenafatua L.) in the dormant state by acting as natural germination inhibitors (Berrie, Buller, Don, Parker, 1979 Plant Physiol 63: 758-764) was investigated. When germination of nondormant seeds was inhibited by treatment with short chain fatty acids, the seeds did not revert to a similar biochemical and physiological state as exhibited by dormant seeds. First, nonanoic acid-induced inhibition of seed germination was not reversed by hormone treatments which normally break dormancy in wild oat seeds. Second, nondormant seeds treated with short chain fatty acids maintained similar relative proportions of the pentose phosphate pathway and the Embden-MeyerhoffParnas pathway for respiratory glucose metabolism as that found in the nondormant controls. Seeds imbibed in the presence of nonanoic acid lost more amino acids and proteins into the imbibition solution than did the untreated controls, suggesting membrane damage had occurred. Inasmuch as increasing concentrations of nonanoic acid also progressively reduced the growth of the coleoptile and roots of intact seedlings until all growth ceased and no germination occurred, the inhibition of seed germination could be due to a nonspecific inhibition of growth of the embryo, perhaps because of disruption of membrane structure and function. Finally, no correlation between endogenous levels of short chain fatty acids in seeds or isolated embryonic axes and seed dormancy could be demonstrated.Seeds of wild oat (Avenafatua L.) are normally dormant at the time of dehiscence from the parent plant; that is, even though fully viable, dormant seeds will not resume growth when supplied conditions that support germination of nondormant seeds (21).Upon dry storage, dormant seeds undergo physiological and biochemical changes, termed afterripening, which cause the transition from a dormant to a nondormant state.Endogenous growth regulators have been implicated in the induction, maintenance, and termination of dormancy in seeds of A. fatua (21). Recently, it has been proposed that volatile fatty acids of chain length C 6-C 10 play a major role in the induction and maintenance of seed dormancy in wild oat by acting as natural germination inhibitors (2). The reasoning behind this hypothesis was 3-fold: first, fatty acids, particularly C 7, C 8, and C 9, were moderately effective inhibitors of seed germination in A. fatua (3). Second, the endogenous levels of fatty acids in dormant seeds were in the range necessary for inhibition of 'To whom correspondence should be addressed. germination of nondormant seeds. Third, and most importantly, there was a strong correlation between the levels of endogenous short chain fatty acids and the degree of dormancy in seeds of wild oat (2). These workers suggested that loss of the fatty acids by evaporation from the seeds could explain the basic mechanism underlying the afterripening process (2).Implicit in this work is the assum...