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Auxin [α-naphthaleneacetic acid (NAA) or indole-3-acetic acid (IAA)] can induce the expression of two lipoxygenases (LOXs) in cultured immature zygotic embryo cotyledons of soybean (Glycine max L.). One of the IAA/NAA-induced LOX isozymes in cultured embryo cotyledons has been demonstrated to be seedling LOX4 (pI 5.09) and another appears to be LOX5 (pI 5.23). The effects of jasmonic acid (JA), methyl jasmonate (MJ), abscisic acid (ABA) and triiodobenzoic acid (TIBA) on the expression of NAA-induced LOXs were investigated in the cultured embryo cotyledons. Among tested plant regulators, only NAA can induce the expression of LOX4 and LOX5, whereas MJ, JA or ABA did not induce LOX expression in the absence of NAA. However combination of NAA with JA significantly increases the expression of NAA-induced LOXs compared with NAA alone. TIBA, an inhibitor of auxin transport, blocks the expressions of the NAA-induced LOXs in the cultured embryos. Immunogold labeling showed that NAA-induced LOXs are located in vacuoles. Our results suggest that auxin may directly or indirectly trigger the expression of soybean seedling LOXs during soybean germination. We also report that seedling LOX4 and/or LOX5 are located in vacuoles.

Qualitative and quantitative changes in haemolymph proteins in Heliothis virescens were observed in larvae injected with either Microplitis croceipes teratocytes or teratocyte secreted proteins (TSP). Haemolymph protein titres in hosts receiving either 0.5 or 1 larval equivalent (LE) of teratocytes were similar to those of parasitized larvae, whereas a single injection of 4LE of TSP was required to induce a similar response. SDS-PAGE showed that the 82kDa monomer of riboflavin-binding protein and the 74/76kDa monomers of storage proteins were significantly reduced in parasitized larvae and in nonparasitized larvae treated with TSP. Concentrations of a 155kDa monomer (insectacyanin chromoprotein) also were reduced in parasitized larvae and those injected with either teratocytes or TSP. Two monomers (56 and 60kDa) were unique to parasitized larvae. Treated larvae required several days longer than controls to reach a comparable premetamorphic stage (burrowing-digging). Reductions in fat body proliferation similar to those seen in parasitized larvae were observed in larvae treated with either 1LE of teratocytes, or with 2 or 4LEs of TSP. Perivisceral fat body weights from larvae treated with either 0.25 or 0.5LE of teratocytes were significantly reduced, but less so than those which received 1LE. Thus, fat body proliferation in both teratocyte- and TSP-treated larvae was inhibited in a dose-dependent manner. Both light- and transmission electron microscopy observations revealed cytological differences in fat body tissues of larvae injected with either teratocytes or TSP from the condition observed in parasitized larvae and noninjected controls. Gross dissection of periviseral fat body from parasitized, teratocyte-injected and TSP-injected larvae showed tissue much less developed and differing considerably in appearance from controls. Observed differences included reduced size and/or number of lipid bodies and qualitative and quantitative changes in other cytoplasmic organelles.

The developing embryo of the braconid, Microplitis croceipes (Braconidae : Hymenoptera), is encased in an extraembryonic serosal membrane. Hatching of the parasitoid within the larva of its habitual host, Hehothis virescens (Noctuidae : Lepidoptera), is initiated about 40 hr after oviposition when held at 25 ± 2°C. At this time, the monolayered serosal membrane begins to dissociate into individual cells (teratocytes). After dissociation, teratocytes become dispersed in the hemolymph of the host. The average number of teratocytes released from each parasitoid embryo is 914 ± 43. Teratocytes average 14.1 ± 2.4 μm in diameter when first released, and reach a maximum average diameter of 68.1 ± 4.6 μm 6 days after liberation. Newly released teratocytes have ovoid nuclei, simple mitochondria and a limited number of profiles of the endoplasmic reticulum, all of which indicate relative metabolic inactivity. The ramified nuclei, extensive endoplasmic reticulum, polymorphic mitochondria and accumulation of glycogen granules and lipid droplets observed in older teratocytes provide circumstantial evidence that protein synthesis is occurring. Within hours after dissociation, microvilli begin to cover the surface of the teratocytes. Anatomical deformation (blebs) that occurred on some older (8-day-old) teratocytes probably resulted from enlargement or expansion of microvilli.

Gross ultrastructural and histochemical details of the integumental milk glands of the tsetse fly Glossina morsitans have been examined during the pregnancy cycle. Structural evidence for protein secretion is found between Days 3–8 of the nine-day cycle: termination of activity is completed on the day of parturition. Onset of lactation is synchronized with the eclosion of the first instar larva. The changes in cell volume (notably in the extracellular reservoir) occurring throughout the pregnancy cycle are illustrated in electron micrographs, and a one hundred-fold volume increase in the reservoir volume between the inactive phase and the active period is illustrated and discussed in terms of membrane modulation of the limiting membrane of the reservoir. Intracellular membrane changes during the cycle, particularly the development of extensive ER arrays in the actively secreting cell, are illustrated and discussed. It is suggested that cytoplasmic microtubules play a part in maintaining the form of the distended secretory cell, at the height of secretory release and storage. Histochemical observations on the milk secretion, and the contents of the larval gut are presented.

Pure preparations of Trypanosoma brucei , free from plasma and cellular components were isolated from rat blood, and concentrated into loose pellets by low-speed centrifugation. Pellets were either processed for thin sectioning as a control for general morphology, or glycerol-treated after glutaraldehyde fixation for preparation of freeze-fracture replicas. Concentration of cells of 50,000–100,000/mm 2 of sectioned or fractured surface facilitated identification of fracture faces of the cell body, invaginated flagellar pocket and flagellum. Particle distribution and A and B faces of these regions of the cell are described. A collar of B face particles occurs around the neck of the flagellar pocket, possibly associated with a junction controlling ingress of ingested materials to coated vesicles formed along the membrane defining the pocket. A and B faces of the flagellum and adjoining surface of the cell body have shown that the only intra-membrane specialization corresponding to the miniature ‘maculae adherentes’ described previously in thin sections is probably an uninterrupted series of small clusters (3–6) of 80 A particles on the A face of the flagellar membrane. It is proposed that these arrays represent attachment points for strands linking the axoneme and paraxial rod to the flagellar surface, and are not directly concerned with the physical adhesion of the flagellum to the cell body surface—a linkage that appears to be established within the extracellular gap between these apposed surfaces of the cell. The potential use of freeze-etching in further study of the external antigens of the infective cell is discussed.

When plasmodia of P. polyeephalutu are fixed simultaneously with osmium tetroxide and glutaraldchyde, the cytoplasm is so preserved that a system of microchannels, resembling pinocytosis channels, and numerous discrete vacuoles can be observed. With either fixative alone, the cytoplasm appears to contain large irregular vacuoles or a vacuolar continuum. The microehannels, approximately l µ in diameter, arising as invaginations of the plasma membrane are each surrounded by a sheath of thin filaments which in areas of invagination at the plasmodial surface seems to merge with a well-defined cortex underlying the plasma membrane. Coating the plasma membrane is a structured slime layer continuous with the microchannel contents. The location and structure of the microchannel-cortex system strongly suggests it as the site for localization of contractile function implicated in cyclosis and motility. Mitochondrial structures of special interest are also described.

Light, required to induce sexual sporulation (fruiting) of the plasmodial myxomycete Physaruin polycephalum , causes the formation of electron-dense deposits in the intermembrane spaces of mitochondria and in cytoplasmic vacuoles. Such mitochondrial deposits are also present but to a much smaller extent in the dark. This deposition is nutritionally dependent on calcium. The deposits are rich in calcium as determined by EGTA treatment of sections and by X-ray spectroscopy. Light also induces the formation of these deposits in young plasmodia not yet competent to sporulate upon exposure to light. In addition, growing microplasmodia which are severely inhibited by light also form these characteristic deposits when illuminated. A basic part of the photometabolism appears to be an enhanced movement of calcium and possibly other ions into and within the plasmodium. The physiological response evoked by light, sporulation or growth inhibition, depends on the nutritional history and immediate environment of the plasmodium.