The contribution of the fatbody to RNA and ribosomal changes during development of the blowfly Calliphora erythrocephala (Meig)

The initiation of blowfly metamorphosis is associated with a pronounced decrease in the number of larval ribosomes; this reduced number then remains constant throughout pharate adult development. Ribosomal RNA accounts for most of the total RNA in larvae shortly after the cessation of feeding and growth, but thereafter the amount of rRNA declines disproportionately to total RNA until early pharate adult development; thereafter, the ratio remains constant until adult emergence. Larval fatbody ribosomes, which constitute about half of the total in the entire organism, are destroyed in situ prior to pupariation. The progressive decrease in fatbody rRNA is accompanied by a corresponding increase in a degraded, relatively insoluble 4–7 S nucleic acid which, stored until adult emergence when it is discarded, accounts for the disparity between total RNA and rRNA. The extracellular ribosomes previously observed during pharate adult development are thus derived from dissolution of larval tissues other than fatbody.     

Structure and kinematics of the prosternal organs and their influence on head position in the blowfly Calliphora erythrocephala Meig.

Summary The blowfly Calliphora has a mobile head and various, presumably proprioceptive, sense organs in the neck region. The prosternal organs are a pair of mechanosensory hair fields, each comprising ca. 110 sensilla. We studied their structure (Figs. 2–4), kinematics (Figs. 5, 6) and, after surgery, their influence on head posture (Figs. 7–11) in order to reveal their specific function.The hair sensilla are structurally polarized, all in roughly the same direction, and are stimulated by dorsoventral bending of the hairs (Figs. 3, 4). This occurs indirectly by flap-movements of two contact sclerites (Figs. 3, 6); they move in the same direction during pitch turns of the head, in opposite directions during roll turns, and barely at all during yaw turns of the head (Fig. 5).Bending and arresting all hairs of one field elicits a head roll bias to the non-operated side (Fig. 7) during tethered flight in visually featureless surroundings. In contrast, shaving all hairs of one field elicits a head roll to the operated side (Figs. 8–10). The surgically induced bias of head posture is not compensated within three days (Fig. 10). Our results show that the prosternal organs of Calliphora sense pitch and roll turns of the fly's head, and control at least its roll position.Abbreviations HP° TP° angular positions of the sagittal planes of the fly's head and thorax, respectively, relative to an external reference - HR° = HP — TP head roll angle of the fly's head relative to its thorax, HR>0° for clockwise head roll, looking in flight direction - N number of flies - n number of measurements - PO prosternal organ - SD standard deviation - SEM standard error of the mean     

The fine structure of haltere sensilla in the blowfly Calliphora erythrocephala (Meig.), with scanning electron microscopic observations on the haltere surface

The dipteran haltere incorporates large numbers of regularly disposed mechanoreceptors providing the sensory input enabling the vibrating haltere to function as a gyroscopic organ of equilibrium. Campaniform sensilla of the basal and scapal regions have been investigated by light and transmission electron microscopy, and these observations are augmented by scanning electron studies of the cuticle overlying the groups of sensilla. Each sensillum possesses a specialized fan-shaped terminal containing a complex and ordered association of microtubules and filaments. The transmission of stress to this region via the cuticle, and its possible role in transduction is considered. The fine structure of apical and basal sections of the distal sensory process and associated sheath cells is described; the functional significance of the distribution of mitochondria and other components is discussed. The organization of haltere chordotonal sensilla is described briefly, and compared with other mechanoreceptors with particular reference to microtubules and scolopale structures.     

Ultrastructural immunocytochemical localization of vitellogenin in the fat body of the blowfly,Calliphora vicina Rob.-Desv. (erythrocephala Meig.) by use of the unlabeled antibody-enzyme method

Summary The unlabeled antibody-enzyme method was used to demonstrate ultrastructurally the specific localization of vitellogenin in the fat body of Calliphora. In control flies the binding sites to vitellogenin were localized in secretory granules situated in the Golgi complex, and in larger bodies named composite secretory granules. These composite granules appear to be formed when a part of a Golgi complex containing secretory granules and a number of small vesicles become surrounded by a common membrane. Ovariectomized flies, which apparently do not produce secretory granules, exhibited no immunocytochemical staining. Ovariectomized flies in which the administration of ecdysterone induced formation of secretory granules, also revealed specific staining on these granules. This is the first ultrastructural evidence of: (a) the specific localization of vitellogenin in secretory granules of the fat body of an insect; (b) the relationship between the presence of the ovary, and of ecdysterone, and the synthesis of vitellogenin by the fat body.     

Distribution of F-actin in the compound eye of the blowfly,Calliphora erythrocephala (Diptera,Insecta)

Summary Sexual stimulation of males has been reported to affect hypothalamic oxytocinergic systems. In the present study we used radioimmunoassays of micro-dissected forebrain regions and immunocytochemical analysis of Vibratome sections to study the oxytocin systems of naive males, males killed after one mating, and males mated daily with different receptive females for 3 weeks. In males that had mated once, less oxytocin-immunoreactive neurons were observed in the paraventricular (PVN), supraoptic (SON) and periventricular (NPE) nuclei than in naive males. However, after repeated matings, the number of immunoreactive neurons and their staining intensity was increased in these regions. Furthermore, additional oxytocinergic neurons could be found in the lateral subcommissural nucleus, the zona incerta and the ansa lenticularis of repeatedly mated males. Oxytocin-immunoreactive neurons were only occasionally seen in these areas in unmated males or in animals that had been killed after initial mating. Radio-immunoassays of microdissected PVN, SON, NPE and the lateral hypothalamus confirmed the reduction in oxytocin-immunoreactive levels after a first mating by a male and the increase after repeated matings. It is likely that oxytocin secretion into peripheral and portal circulation is stimulated by the endocrine conditions associated with initial mating. These immediate effects may be followed by the activation of synthesis in oxytocin neurons in several sites of the basal forebrain.     

Blood vascular architecture of the rat lingual papillae with special reference to their relations to the connective tissue papillae and surface structures: a light and scanning electron microscope study

Subepithelial blood vessels of the rat lingual papillae and their spatial relations to the connective tissue papillae and surface structures were demonstrated by light and scanning electron microscopy. In the rat, four types of papillae were distinguished on the dorsal surface of the tongue, i.e. the filiform, fungiform, foliate and circumvallate papillae. Vascular beds of various appearance were found in all four types of lingual papillae: a simple or twisted capillary loop in the filiform papilla; a basket- or petal-like network in the fungiform papilla; a ring-like network in the foliate papilla, and a conglomerated network surrounded by double heart-shaped capillary networks in the circumvallate papilla. These characteristic vascular beds corresponded to the shape of the connective tissue papillae and surface structures. The vascular bed beneath the gustatory epithelium in the fungiform, foliate and circumvallate papilla consisted of fine capillary networks next to the taste buds.     

Functional-morphological investigations on the flight muscles and their insertion points in the blowfly Calliphora erythrocephala (Insecta,Diptera)

Summary In flies, for example the blowfly Calliphora erythrocephala, the thorax has fused to form a chitinous capsule. In it we find three functional types of flight muscles, the indirect flight muscles, the direct, and the tension muscles. The indirect or wing beat muscles transfer their power to the capsule which is capable of oscillating. They are suspended nearly horizontally and vertically. The direct muscles used for steering insert laterally on the capsule and go to the wing joint. The third functional type of flight muscle serves to put the lateral walls of the thorax under tension. The site and morphology of the flight muscles are described in detail, making use of 3-dimensional drawings. The flight muscles of Calliphora erythrocephala (Heide 1968) and their functions are compared with those of other dipterans described by different authors.With support of the Deutsche Forschungsgemeinschaft to Professor Nachtigall     

Immunofluorescent localization of insulin-like material in the median neurosecretory cells of the blowfly,Calliphora vomitoria (Diptera)

Summary Immunocytochemical staining has shown that the median neurosecretory cells (MNC) of the brain of the blowfly, Calliphora vomitoria, contain an insulin-like material which cross reacts with antibodies to bovine insulin. There are 24–26 paraldehyde fuchsin-positive MNC of which only 6–8 show the specific insulin-like immunoreactivity.Dr. M.C. Thorndyke, Department of Zoology, Bedford College, London University, kindly provided us with fluorescence facilities, and we are also grateful to him for helpful discussions on the immunofluorescence procedure