Showing papers in "International Journal of Insect Morphology & Embryology in 1979"
TL;DR: Studies, especially with transmission electron microscopy of developmental stages, show that the many superficially different spines, bristles, hairs, etc. can be classified into 4 major types: multicellular with cells similar to those of the general epidermis (spines); multicesllular with differentiation of a segregated trichoid complex (setae); unicellular (acanthae); and subcellular in the sense of several or many per cell (microtrichia).
Abstract: Studies, especially with transmission electron microscopy of developmental stages, show that the many superficially different spines, bristles, hairs, etc. can be classified into 4 major types: (1) multicellular with cells similar to those of the general epidermis (spines); (2) multicellular with differentiation of a segregated trichoid complex (setae); (3) unicellular (acanthae); and (4) subcellular in the sense of several or many per cell (microtrichia). Except for eversible pouches, there are no flaccid projections because the cuticle of setae and other projections is always sclerotized. Spines, as the term is used above, occur primarily on external surfaces, except for comparable structures in the proventriculi of some insects. Setae are on external surfaces only, and most of them retain a sensory function. Acanthae are best known on internal surfaces of foregut and reproductive ducts but can be found on external surfaces also. Microtrichia occur mostly on external surfaces but occasionally on the taenidia of tracheae. Only the socketed setae include one or more sense cells, and hence only setae are sensory (but spines can bear setae). Several or numerous subtypes can be recognized for each of these types. All of the types can have the cells withdraw; they then usually become filled with cuticle and even commonly become underlaid by cuticle; the producing cells may or may not persist. Such solid hairs commonly cannot be identified as to type without knowledge of their development.
93 citations
TL;DR: Evidence of direct contact in the sensory cell between endoplasmic reticulum and onion body suggests a role in protein secretion for the latter.
Abstract: The antenna of the cat abid beetle, Nebria brevicollis, has approximately 5775 sensilla, 84% trichoid and 16% basiconic, represented by 4 and 3 size classes respectively. The ultrastructure of trichoid type 1 (44 ± 1 μm long, 78.3% of all sensilla) is characterised by a single neuron whose dendrite terminates in a tubular body and by 4 enveloping cells with a complex system of interconnections. Trichoid type 2 (55 ± 0.9 μm long, 4.2% of all sensilla) has 5 neurons one of which terminates in a tubular body and the others are unbranched in the peg. The peg of the basiconic type I sensillum (5.2 ± 0.2 μm long, 14% of all sensilla) is perforated by about 870 pores, from which pore tubules run to the much branched dendrites of 2 neurons. The presence of pinocytotic 40 nm vesicles in the microvilli of a basiconic enveloping cell indicates it has a secretory function. Evidence of direct contact in the sensory cell between endoplasmic reticulum and onion body suggests a role in protein secretion for the latter.
55 citations
TL;DR: Salivary glands of the unfed tick Boophilus microplus contain three types of acini, and cells, which were insignificant in the types II and III acini of unfed ticks, develop during the early stages of feeding and are probably eventually responsible for the secretion of the excess fluid formed from the concentration of the blood meal.
Abstract: Salivary glands of the unfed tick Boophilus microplus contain three types of acini. Pyramidal cells in the type I acini have morphological characteristics indicative of epithelia involved in the secretion of hyperosmotic fluids. Granule-secreting cells in the types II and III acini are considered to secrete the enzymes and cement components required during feeding. Cells, which were insignificant in the types II and III acini of unfed ticks, develop during the early stages of feeding and are probably eventually responsible for the secretion of the excess fluid formed from the concentration of the blood meal.
48 citations
TL;DR: The tergal glands in Blattella germanica exist only in the adult male, and are involved in courtship behavior, and have a thick glandular epithelium.
Abstract: In Blattella germanica , as in many other cockroaches, the tergal glands exist only in the adult male, and are involved in courtship behavior. These glands are found on segments 7 and 8, which are markedly modified. They occupy a transverse depression divided into two by a central ridge. The two glands go deeply under tergites 7 and 8, and have a thick glandular epithelium. The depressions serve as reservoirs for the secretion. The central pillars dividing the depressions possess numerous setae that are both mechano- and chemoreceptors. The tergal glands have only 3 basic types of cells: (1) epidermal cells that secrete the tergite cuticle and the cuticular lining of the reservoir; (2) associated cells filled with microtubules; (3) large gland cells (type 3) with a cuticular duct (secreted by the canal cells) that connects the glandular cells with the outer cuticle. There are 2 subtypes in the type 3 cells: (G1) the cells filled with dense myeloid bodies, probably constituting the glycoproteinic part of the secretion; (G2) the cell is filled with electronluscent vacuoles. These cells are 3-times more numerous than the G1 cells, and probably secrete the volatile components (free fatty acids, para-hydroxy benzylic alcohol, O -hydroxy benzylic alcohol, di- and tri-methyl naphthalene and benzothiazole. Detailed structure and functional interpretation are discussed.
37 citations
TL;DR: The evidence suggests that aberrant fusome formation is the underlying cause of the atypical patterns of cytokinesis characterizing the fs231 mutation.
Abstract: The three-dimensional arrangements of tumor cells were analyzed in reconstructions made from electron micrographs of serially sectioned ovaries of Drosophila melanogaster homozygous for the female sterile (1) 231 mutation. Special attention was paid to the pattern of fusomes extending through ring canals between interconnected tumor cells. Cystocytes within mutant ovaries undergo 3-4 supernumerary cell divisions; the probability of complete cytokinesis being 0.53. The occurrence of long, unbranched chains of interconnected cells suggests that the spindles are sometimes oriented abnormally at mitosis, parallel to the long axis of the cluster. The rims of canals between cystocytes do not appear to undergo the normal morphological changes during development. Tumor cells with 4 or 5 canals were observed, but these did not differentiate into oocytes. Fusomes were found in all sectioned canals, but fusomes often were not joined within cells having 2 or more canals. A loss of mitotic synchrony was observed within certain clusters. The evidence suggests that aberrant fusome formation is the underlying cause of the atypical patterns of cytokinesis characterizing the fs231 mutation.
26 citations
TL;DR: The fine structure of the vitelline membrane, the chorion and the serosal cuticle of the egg of Korscheltellus lupulinus L. L. (Lepidoptera: Hepialidae) is described and a crystalline material was found to be a constituent of theChorion of this egg.
Abstract: We describe the fine structure of the vitelline membrane, the chorion and the serosal cuticle of the egg of Korscheltellus lupulinus L. (Lepidoptera: Hepialidae). We studied the details of secretion and morphogenesis of the vitelline membrane. The follicle cells produce the vitelline membrane material, while the oocyte controls the morphogenesis of the envelope. Structural changes were observed in the vitelline membrane. For example, thickening before oviposition and melanization and sclerotization after oviposition. A crystalline material was found to be a constituent of the chorion of this egg. The serosal cuticle resembles an endocuticular material of insect integument.
22 citations
TL;DR: Sunken cuticular pore plates were found on the legs of 5 of the 12 isopteran genera examined with the scanning electron microscope and the histological structure of the gland associated with the plates of the right foreleg of Reticulitermes lucifugus (Rossi).
Abstract: Sunken cuticular pore plates, which vary in size and shape, were found on the legs of 5 of the 12 isopteran genera examined with the scanning electron microscope. The histological structure of the gland associated with the plates of the right foreleg of Reticulitermes lucifugus (Rossi) is described. Gland cells and ductule cell nuclei are distinguishable by size and shape, while the conspicuous spherical body of the gland cell often has a distinct ductule connecting the ductule cell. Large ducts connect to ductule cells associated with the pore plates. The function of the gland is discussed with relevant work and its role in defence is suggested.
21 citations
TL;DR: Detailed study of the nymph gland secretory proteins, using SDS-micro gel electrophoresis, iso-electric focusing and immunodiffusion indicates that regional specialization for export protein synthesis exists in the nmph as well as in the adult gland, and differences between the 2 stages may be largely quantitative.
Abstract: The male accessory gland of the adult cricket, Acheta domesticus, produces a complex mixture of proteins. The protein population made by the late last-instar nymph gland appears to be less complex than that of the adult when analysed on SDS-polyacrylamide gels. However, detailed study of the nymph gland secretory proteins, using SDS-micro gel electrophoresis, iso-electric focusing and immunodiffusion indicates that regional specialization for export protein synthesis exists in the nymph as well as in the adult gland, and differences between the 2 stages may be largely quantitative.
Ultrastructural studies show that after the final molt the gland rapidly assembles large quantities of rough endoplasmic reticulum (RER). Differences in the timing of membrane appearance may exist between adjacent cells. In some secretory cells of the glands isolated from animals immediately after the imaginal molt, RER forms near the nucleus, where the RER membranes take on a whorl-like configuration. The development of the RER reaches a peak in the glands of 2–3-week-old adults, with the membranes and their enclosed cisternae arranged in parallel arrays. Apical and basal Golgi complexes of similar morphology have been observed, with poorly developed cisternal elements, large vacuoles and numerous small vesicles.
19 citations
TL;DR: The presence in this species of trophic cords within the ovarioles is confirmed and may indicate this to be a widespread phenomenon in the Aphididae.
Abstract: The structure and function of the components of the telotrophic ovariole of Brevicoryne brassicae are described, with the aid of transmission electron microscopy. It was of interest to determine the presence of trophic cords in this aphid species. Oocytes are extruded posteriorly from the germarium and become surrounded by follicle cells which occupy a small region at the base of the germarium. The follicle cells do not contribute yolk to the oocytes and whilst lipid yolk is present within oocytes, they lack protein yolk. The trophocytes and oocytes are connected by a nutritive cord which contains many microtubules. Export of rRNA, mitochondria, and possibly lipid from the trophocytes to the oocytes takes place. Oocytes emerge from the surrounding layer of follicle cells shortly before nuclear division, and follicle cells do not accompany the embryo down the ovariole. The germarial structure resembles that of other aphids but differs from other hemipterans, which may be a result of the different reproductive strategy of parthenogenetic viviparous aphids. This study confirms the presence in this species of trophic cords within the ovarioles and may indicate this to be a widespread phenomenon in the Aphididae.
19 citations
TL;DR: Type and distribution of sensilla are similar to those observed by light microscope in different mosquitoes, except for some minor details, and show no sexual or specific differences either in appearance or number.
Abstract: The inner surface of the cibarium was studied with scanning electron microscope. Types and distribution of sensilla are similar to those observed by light microscope in different mosquitoes, except for some minor details. On the dorsal wall are 4 types of sensilla: palatal papillae, campaniform sensilla, dorsal papillae and trichoid sensilla. Except the last-named, they show no sexual or specific differences either in appearance or number. Trichoid sensilla in A. albopictus differ in number between males (2 pairs) and females (3 pairs). Ventral papillae on the ventral wall are hair-like in Aedes and pyriform in Culex . The pharyngeal valves comprise dorsal and ventral valves, derived respectively from the respective walls of the cibarium. The dorsal valve has projections that are digitate in Aedes and lanceolate in Culex . Distribution of these projections differs with sex in Culex , but not in Aedes . The ventral pharyngeal valve in both sexes of Aedes bears finger-like projections; those in females of Culex bear rows of teeth along the hind margin that appears smooth in the males.
18 citations
TL;DR: This study provides the first description of the L. reclusa venom gland in addition to supporting the use of venom obtained from spiders by electrical stimulation, and Morphological evidence of neuroglandular control of the apical venom release is presented.
Abstract: Studies were conducted to describe the histology and fine structure of the venom gland of the brown recluse spider, Loxosceles reclusa, and to provide information about venom production and secretion. The L. reclusa venom glands are paired bulbous structures, located in the cephalothoracic cavity; the glands diminish proximally into cuticle-lined ducts that lie within the cheliceral fangs. The secretory epithelium is surrounded by a thick, striated musculature composed of irregularly shaped muscle bundles and is ensheathed by a basement membrane. The venom-producing cells of the gland are pyramidal epithelial cells which extend into the central portion of the gland. The secretory products of the venom gland are produced in the basal area of the epithelial cells as Golgi-associated, membrane-bounded packets of different electron densities and subsequently fuse with a large apical vacuole. Morphological evidence of neuroglandular control of the apical venom release is presented. Evacuation of the gland, following venom release, is subsequently promoted by the constriction of the large musculature. Comparison of venom glands from electrically depleted and normalbiting situations reveals no morphological differences. This study provides the first description of the L. reclusa venom gland in addition to supporting the use of venom obtained from spiders by electrical stimulation.
TL;DR: The development of the ocelli is compared to that of the compound eye and the continued extension of the interneuron axons brings all the synaptic contacts to lie within a plexus in the o cellus itself.
Abstract: The embryonic and postembryonic development of the ocelli of Schistocerca gregaria have been examined by means of both light and electron microscopy. The 3 ocelli of the adult locust are derived from 4 embryonic rudiments of epidermal origin present in the embryo. Two of these rudiments each form a lateral ocellus, and 2 fuse on the midline to form a single median ocellus. Presumptive retinula cell axons grow across the space between the rudiment and the brain, later interneuron axons grow out along this path into the ocelli. The possible importance of contact guidance in this growth sequence is discussed. The number of visual and supporting cells within the ocellar retina increases during development. New cells are the products of mitotic divisions occurring at the ocellar margins. In the embryo and early instars retinula axons are found making synaptic contact with interneurons both within the ocellar nerve and the brain. In later instars and the adult, the continued extension of the interneuron axons brings all the synaptic contacts to lie within a plexus in the ocellus itself. The expansion of the ocellar retina during development is associated with increases in the volume and complexity of the branching patterns of the interneurons within the ocellar synaptic plexus. The development of the ocelli is compared to that of the compound eye
TL;DR: The glandular activity is important during the first 24 hr of imaginal life or after a period of intense sexual activity.
Abstract: In Acanthoscelides obtectus , the male reproductive system has 4 pairs of accessory glands. Their general organization, ultrastructural and cytochemical characteristics have been established in relation to sexual activity. The elaboration of the different glycoproteinic secretions and their transfer toward the apical part of the cells have been examined. The role of endoplasmic reticulum in elaboration and transfer of secretions is important. The function of the Golgi apparatus is less pronounced. The excretion of the secretion granules occurs either at the junction of the endoplasmic reticulum-cytoplasmic membrane (inferior or median glands) or by exocytosis (tubular glands). The glandular activity is important during the first 24 hr of imaginal life or after a period of intense sexual activity.
TL;DR: The fine structure of the developing oocytes of the grylloblattodean, Galloisiana nipponensis, was described by transmission and scanning electron microscopy by giving particular attention to the peripheral ooplasm, the surrounding follicular epithelium and the surfaceructure of the micropylar area.
Abstract: This paper describes the fine structure of the developing oocytes of the grylloblattodean, Galloisiana nipponensis by transmission and scanning electron microscopy. Particular attention was given to the peripheral ooplasm, the surrounding follicular epithelium and the surface structure of the micropylar area. An ovariole contains a linear array of about 12 developing oocytes in different stages; the anterior 9 oocytes (1–9) show previtellogenic stages, the 10th and 11th oocytes the vitellogenic stages, and the 12th oocyte at the posterior end of the ovariole is fully grown and black. In the previtellogenic stages when oocytes grow in volume, the follicular cells change their shape from flattened to cuboidal, and then to columnar. During the vitellogenic stage, lamellae or whorls of rough endoplasmic reticulum and Golgi bodies develop considerably in the cytoplasm of columnar follicular cells. In the final stage of oogenesis, a thin vitelline membrane (0.4–0.5 μm) and a thick, highly electrondense chorion (9–9.3 μm) with disc-shaped projections are deposited rapidly by the follicular cells that concurrently develop rough endoplasmic reticulum and Golgi bodies. There are 8–10 micropyles (1.1–1.2 μm dia), somewhat circularly distributed around the anterior end of the egg.
TL;DR: Histochemical and autoradiographic investigations of the sites of RNA synthesis in telotrophic ovarioles of Crynodes peregrinus showed that trophocytes synthesise RNA in their large polyploid nuclei and supply the products to the oocytes via trophic cords, and 3 possible sources of RNA supply to the euplasmic growth are indicated.
Abstract: Histochemical and autoradiographic investigations of the sites of RNA synthesis in telotrophic ovarioles of Crynodes peregrinus were carried out. Oocyte growth occurs in 4 stages. Stages I and II are previtellogenic stages (euplasmic growth), stage III is vitellogenic while stage IV is a postvitellogenic stage, having chorionated eggs. RNAse-sensitive basophilic reaction is noticeable in follicle epithelial cells, trophocytes, oocyte cortex and germinal vesicle. 3 H-uridine incorporation patterns showed that trophocytes synthesise RNA in their large polyploid nuclei and supply the products to the oocytes via trophic cords. Follicle cells also synthesise RNA, which, up to early stage III, seems to be exported to the oocyte, but later, is perhaps retained in the cells for synthesis of chorion precursors. Germinal vesicle is also actively involved in RNA synthesis up to stage II and subsequently this diminishes or ceases completely. This represents an intermediate condition between polytrophic ovarioles where the germinal vesicle is practically idle and panoistic ovarioles, where it actively synthesises RNA throughout. Thus, 3 possible sources of RNA supply to the oocyte are indicated and all these seem to contribute to its euplasmic growth.
TL;DR: The secretion of the glands from weevil less than 24-hr old apparently differs from those of 3-day old weevils.
Abstract: The secretion of the spermathecal gland, an epidermal derivative, has been suggested as the source of nutrients for the sperm which are stored in the spermatheca. This secretion is also necessary for spermathecal filling. The gland consists of 2 types of cells, secretory cells and collecting or ductule cells. The products of the secretory cells are deposited in a central cavity lined with microvilli. The collecting ductule extends into the central cavity and the secretory products move down the ductule into the central lumen of the gland. The contents of the gland are then deposited in the spermatheca. The ductules, ducts and the central lumen of the gland are lined with cuticle, as is the spermatheca. The secretion of the glands from weevils less than 24-hr old apparently differs from those of 3-day old weevils.
TL;DR: This study was undertaken to provide information needed for interpretation of electrophysiological data on the lateral sensilla and to shed some light on the function of the medial sensillum.
Abstract: The structures of 2 sensilla on the larval galea are described. Both sensilla have multiple innervation and one of them, the lateral sensillum, is known to be a contact chemosensillum. The function of the second, medial sensillum, is unknown. This study was undertaken to provide information needed for interpretation of electrophysiological data on the lateral sensillum and to shed some light on the function of the medial sensillum. The lateral sensillum is uniporous and is innervated by 5 cells, one of which has a well-developed tubular body and ends near the sensillum socket, while the remaining cells communicate with a pore in the sensillum tip. The medial sensillum is innervated by 2 cells, neither of which has an apparent tubular body. Both of these cells have dendrites that run to the sensillum tip. No pore has been demonstrated in the tip of the medial sensillum by scanning and transmission electron microscopy and electrophysiological techniques. This sensillum is also unusual in that it has no apparent distal dendritic sheath. Its structure is compared with that of similar sensilla in other insects and some of its possible functions are considered.
TL;DR: The epithelial cells of the basal pads exhibit features characteristic of transporting epithelia and the fine structure of the gill lamellae is typical of respiratory epithelIA, which contributes to the role of the hindgut in both respiration and ionic regulation.
Abstract: The organization of the hindgut in the larva of the New Zealand dragonfly, Uropetala carovei is described. The hindgut is divided into 2 regions, the anterior colon and the rectum. The rectum itself is divided into a large anterior branchial chamber, housing the heavily tracheated respiratory gill lamellae, and a short posterior vestibule. The gills of the branchial chamber are arranged in 6 rows, each row comprising a series of paired gill lamellae that arise from the luminal tips of the rectal pads, that are formed from 6 longitudinal rows of thickened epithelial cells. Each pad encloses a medulla of fat body cells. Most of the branchial chamber is lined with a thin layer of epithelial cells, underlying a thin layer of cuticle. Ultrastructural features of the Malpighian tubules, the colon, the 3 regions of the anterior rectum and the posterior rectum are described. The epithelial cells of the basal pads exhibit features characteristic of transporting epithelia and the fine structure of the gill lamellae is typical of respiratory epithelia. The role of the hindgut in both respiration and ionic regulation is discussed.
TL;DR: Electron microscopy provides reliable evidence that this central cy toplasmic mass is in good part derived from cortical cytoplasm and oolemma microvilli of the undivided egg, both carried centripetally by the ingrowth of segmentation furrows.
Abstract: In collembolan embryos, light microscopy has shown that germ cell segregation takes place in the geometric center of the egg, inside a cytoplasmic mass that appears during total segmentation. Electron microscopy provides reliable evidence that this central cytoplasmic mass is in good part derived from cortical cytoplasm and oolemma microvilli of the undivided egg, both carried centripetally by the ingrowth of segmentation furrows. The central mass contains “oosome-like” fibro-granular material, clearly derived from the posterior polar region of the egg. However, due to technical difficulties, it remains to be proved that the fibro-granular material derives from the tiny plasm observed by light microscopy at the posterior pole of the undivided egg. In the central cytoplasmic mass, the membranous components of microvilli must play a role in the formation of the membranes that surround germ cells. The fibro-granular material seems responsible for the slowing down and the arrest of germ cell divisions, i.e. for the most oosome-like property of the central mass. Some peculiarities of early germ cell development are described and discussed.
TL;DR: The females of the carpenter bee Xylocopa pubescens have 3 pairs of abdominal glands, one each on the ventrolateral aspect of segments 5, 6 and 7, where a mucopolysaccharide, containing carboxyl groups of the hyaluronic acid type, is secreted.
Abstract: The females of the carpenter bee Xylocopa pubescens have 3 pairs of abdominal glands, one each on the ventrolateral aspect of segments 5, 6 and 7. The glands are active during the nesting period, when their color is bright yellow. Before that, in young bees, they are compact and white. The glands are composed of numerous unicellular secretory elements, each of which is connected to a ductule that empties into the intersegmental membrane. The fine structure of the secretory cell includes an end-apparatus and other well-known features such as secretory vesicles, microvilli and RER. The end-apparatus, which is extracellular, is surrounded by a rather dense intracellular network of compact filaments that are arranged in ring-like structures and may serve as supporting and/or contractile elements. The extensive rough endoplasmic reticulum is indicative of the production of proteinaceous substances to be secreted. In addition, a mucopolysaccharide, containing carboxyl groups of the hyaluronic acid type, is secreted. These materials can be seen accumulating in a cavity outside the gland, and probably serve to coat the inside of the cells in which the bees' progeny develops. Each gland cell passes through a cycle from inactivity through a secretory phase to degeneration. However, the activity cycles of the different cells in each gland are asynchronous, thus prolonging the glands' period of activity, to fit with the length of the bee's nesting period.
TL;DR: It is shown, for the first time, that larval testes are bordered by basal lamina secreted by certain hemocytes, the plasmatocytes, which constitute the perifollicular tissue packing of the gonad.
Abstract: Larval testes of Leptinotarsa decemlineata consist of 3 types of germinal cells: primary spermatogonia, secondary spermatogonia and spermatocytes. Meiotic prophase begins and continues until pachytene stage; its continuation and spermiogenesis occur during larval development. A mesodermal cell, the cystic cell, always separates the hemocoele and germinal cells. Secondary spermatogonia are connected by cytoplasmic bridges that contain only rough vesicular endoplasmic cisternae. The primary spermatocytes have more numerous bridges in which the rough vesicular endoplasmic cisternae become pronounced; likewise, the other cytoplasmic organelles increase in number and size during the prophase. The nucleus contains 2 divided nucleoli in the gonia; they are more compact in the spermatocytes. All germ cells show numerous extrusions of RNP particles. The cytoplasmic discharge of these particles through nuclear pores is progressively reduced in the secondary spermatogonia and in the pachytene spermatocytes. In these latter cells, the “nuages” are frequently associated with some mitochondria. Gonia and spermatocytes have cytoplasmic bulges, extruding small vesicles in the cystic cells. These extrusions probably avoid later degeneration. Nevertheless, the gonial necroses are frequent; they occur in 2 patterns: (1) during gonial destruction, death of the cystic cell precedes one of the gonia; it thus seems that the cystic cell is necessary for the maintenance of germinal cell integrity; (2) during the spermatocyte necrosis, this same cell phagocytoses the spermatocytes, and protects the gonad against a greater degradation. The cystic cells, which remain undamaged, from an interstitial tissue that communicates with the basal part of the testicular lobes. Certain testicular somatic cells, situated both in the basal part of the testes, and the spermduct, are secretory. Their cytolytic secretions cause a hollowing out of the intra- and extra-testicular vasa deferentia. We have shown, for the first time, that larval testes are bordered by basal lamina secreted by certain hemocytes, the plasmatocytes. They insert between the cysts and divide the gonads into testicular follicles. Plasmatocytes thus constitute the perifollicular tissue packing of the gonad.
TL;DR: Three paired groups of the median neurosecretory cells (M1, M2 and M3) were found in the brain of the mature larva of Chironomus plumosus L., staining with paraldehyde-thionin and phloxine or with paraldehydefuchsin.
Abstract: Three paired groups of the median neurosecretory cells (M1, M2 and M3) were found in the brain of the mature larva of Chironomus plumosus L., staining with paraldehyde-thionin and phloxine or with paraldehyde-thionin and paraldehydefuchsin. Group M1 is composed of 12 cells of 3 types, which are named A1-, A2- and A2′-cells. The fibres of the A1-cells form a neurohaemal zone in the aorta wall, whereas the fibres of the A2- and A2′-cells form a neurohaemal zone not only in the aorta wall, but also in the nervus cardio-stomacale, nervus corporis allati and nervus stomacale. The fibres of the cells composing groups M2 and M3 run into the ventral nerve cord, do not apparently leave the ganglionic neuropile and connectives, and do not form any neurohaemal zone. Thus, the neurosecretory nature of these cells is questionable.
TL;DR: The results suggest that the coagulocytes play an exclusive part in initiating plasma coagulation in Gryllotalpa sp.
Abstract: The structural changes in the coagulocytes of Gryllotalpa sp. (Orthoptera) during in vitro hemolymph coagulation have been observed under the phase contrast (PCM) and transmission electron (TEM) microscopes. Among the extremely rapid changes, the most characteristic consisted of the development of multiple microruptures in the plasma membrane, accompanied by ejection of cytoplasmic material and simultaneous clotting reaction of the surrounding plasma. During these changes, the plasma membrane of the other categories of hemocytes (prohemocytes, plasmatocytes and granulocytes) remained intact. No distinct reaction appeared in the plasma surrounding these hemocytes. Occasional ultrastructural changes in these hemocytes occurred later when the plasma coagulation had already taken place. The results suggest that the coagulocytes play an exclusive part in initiating plasma coagulation. Differences in the reaction of the plasma membrane to foreign surfaces could explain the functional contrast between the active coagulocytes and the other hemocytes, at least at the beginning of coagulation of the hemolymph.
TL;DR: The corpora allata (CA) of newly transformed versus sexually matured ovipositing female Xyleborus ferrugineus beetles were compared using both scanning and transmission electron microscopy to identify CA characteristics that are unique to each age insect.
Abstract: The corpora allata (CA) of newly transformed versus sexually matured ovipositing female Xyleborus ferrugineus beetles were compared using both scanning and transmission electron microscopy. The objective was to identify CA characteristics that are unique to each age insect. The surfaces of the spherical CA of newly emerged sexually immature females are initially rough in comparison with the smooth-surfaced CA of the 9-day-old ovipositing adult female. CA are enveloped by a continuous noncellular sheath of varying thickness. Gland cells in CA are closely packed. Some nucleoli of gland cells in CA of ovipositing beetles have a central core which is less electron-dense, but such a core is lacking in the CA of newly transformed females. Mitochondria, with well-developed cristae bathed in an electron-dense matrix, are well dispersed throughout the cells at both stages. Free ribosomes and lysosomes are present in the cells. Golgi complexes are not conspicuous. There is a sparse system of rough-surfaced endoplasmic reticulum (RER). A smooth-surfaced endoplasmic reticulum system is strikingly widespread in the CA cytoplasm of ovipositing females, but is absent in that of the newly emerged females. Neurosecretory axons, filled with electron-dense neurosecretory granules, not only are distributed in the peripheral portion of the CA, but some also penetrate deeply inside the gland. Axons without neurosecretory granules also are present.
TL;DR: The comparative development of the different components of the germarium is described during 4th and 5th larval stages, in Roscius elongatus and R. brazzavilliensis, which diapauses.
Abstract: The comparative development of the different components of the germarium is described during 4th and 5th larval stages, in Roscius elongatuswhich does not diapauee and in R. brazzavilliensis, which diapauses. The first species shows 9 ovarian stages, the second 8 ; only the first 5 stages are common to both species. In R. elongatus, the growth of the egg is rapid and massive, while in R. brazzavilliensis it is slower and smaller. In R. elongatus, the meiosis begins at about the 4th stage. In R. brazzavilliensis, it takes place just before entering the diapause. The development of a peripheral epithelium around the tunica propria of the ovary is described. This may serve some purpose in the ovogenesis. At the level of the pars intercerebralis, there are 6 types of neurosecretory cells. The A' cells appear to control the meiosis, and the A and A' cells the transformation of the oocytes during previtellogenesis. The neurosecretory material of the A' cells is supposed to be similar to the brain hormone.
TL;DR: The cystocytes of intersexual ovaries show the same abnormalities of cytokinesis that characterize females homozygous for the female sterile genes fs (1) 1621, fs ( 1) 231, fu and fes .
Abstract: The ovaries of triploid intersexes are characterized by tumors that contain hundreds of cells, many of which are mitotically active. These cells resemble germarial cystocytes in that they are often interconnected by ring canals and can sometimes differentiate into endopolyploid cells that resemble ovarian nurse cells. More rarely a tumor cell will follow the oocyte developmental pathway and form organelles such as synaptonemal complexes and annulate lamellae. 2X 3A cystocytes do not decrease in volume with each consecutive division as is normally the case. Since the value for the number of ring canals per 100 sectioned tumor cells from 2X 3A intersexes is only about 70% the value for normal germarial cystocytes, we conclude that the cystocytes from intersexes often undergo complete cytokinesis. Thus the cystocytes of intersexual ovaries show the same abnormalities of cytokinesis that characterize females homozygous for the female sterile genes fs (1) 1621, fs (1) 231, fu and fes .
TL;DR: Five types of neurosecretory cells, A, A′, B, C and D were recognized histologically as well as histochemically in the brain of adult Gryllus bimaculatus and it is demonstrated that lipids are abundant in A cells and tyrosine in C cells.
Abstract: Five types of neurosecretory cells, A, A′, B, C and D were recognized histologically as well as histochemically in the brain of adult Gryllus bimaculatus . They are distributed in 3 distinct neurosecretory centers: the median neurosecretory center which consists of an anterior and a posterior part; the lateral neurosecretory center and the tritocerebral neurosecretory center. Histochemical investigations demonstrate that lipids are abundant in A cells and tyrosine in C cells.
TL;DR: Electron microscopic study of mid-segmented Clitumnus embryos showed several specific organelles, chiefly annulate lamellae, in the cytoplasm of the primordial germ cells, which could thereafter be used as markers to track germ cells from earlier embryonic stages up to their very first appearance in the superficial layer of the very young embryo, shortly before the end of mesoderm formation.
Abstract: Electron microscopic study of mid-segmented Clitumnus embryos showed several specific organelles, chiefly annulate lamellae, in the cytoplasm of the primordial germ cells. These organelles could thereafter be used as markers to track germ cells from earlier embryonic stages up to their very first appearance in the superficial layer of the very young embryo, shortly before the end of mesoderm formation.
TL;DR: Pissodes strobi larvae, pupae and adults were dissected at 24-hr intervals, and the length of the ganglia and interganglionic connectives was measured.
Abstract: Pissodes strobi larvae, pupae and adults were dissected at 24-hr intervals, and the length of the ganglia and interganglionic connectives was measured. The larval ventral nerve cord consists of the suboesophageal ganglion, 3 thoracic and 8 abdominal ganglia. The adult ventral nerve cord consists of the suboesophageal ganglion, a thoracic ganglionic mass, an abdominal ganglion and a terminal ganglionic mass. The first ganglia to fuse are the 2 most posterior abdominal ganglia. These are the only ganglia to fuse in the larval stage. Next the 3 ganglia preceeding the terminal 2 fuse with them. Once begun, these fusions take only 2–3 days. The formation of the thoracic ganglionic mass takes 14 days. First to fuse are the third thoracic ganglion and the first abdominal ganglion. Next, the second abdominal ganglion fuses with these and finally the second thoracic ganglion. Of the original larval ganglia, only the first thoracic ganglion and the third abdominal ganglion remain independent.