Salivary glands and salivary pumps in adult Nymphalidae (Lepidoptera)

The salivary glands and salivary pumps were investigated by means of dissection and serial semithin sections in order to expose the anatomy and histology of Nymphalidae in relation to feeding ecology. The paired salivary glands are tubular, they begin in the head, and extend through the thorax into the abdomen. The epithelium is a unicellular layer consisting of a single cell type. Despite the uniform composition, each salivary gland can be divided into five anatomically and histologically distinct regions. The bulbous end region of the gland lies within the abdomen and is composed of highly prismatic glandular cells with large vacuoles in their cell bodies. The tubular secretion region extends into the thorax where it forms large loops running backward and forward. It is composed of glandular cells that lack large vacuoles. The salivary duct lies in the thorax and also shows a looped formation but is composed of flat epithelial cells. The salivary reservoir begins in the prothorax and reaches the head. Its cells are hemispherical and bulge out into the large lumen of the tube. In the head the outlet tube connects the left and right halves of the salivary gland, and its epithelial cells are flat. The salivary pump lies in the head ventral to the sucking pump and leads directly into the food canal of the proboscis. It is not part of the salivary gland but is derived from the salivarium. Both the thin cuticle of the roof of the salivary pump and the thick bottom are ventrally arched. Paired muscles extend from the hypopharyngeal ridges and obviously serve as dilators for the pump. A functional interpretation of the salivary pump suggests that when not in use, the dilators are not contracted and the pump is tightly closed due to its own elasticity. When the dilator muscles repeatedly contract, the saliva is forced forward into the food canal of the proboscis. The salivary gland anatomy was found to be similar to other Lepidoptera. Furthermore, the histology of the salivary glands is identical in all examined butterflies, even in the species which exhibit specialized pollen-feeding behavior.     

A cytochemical study of the leaf-gland enzymes of insectivorous plants of the genus Pinguicula

Summary Cytochemical methods have been used to study the distribution of acid phosphatase, esterase, ribonuclease, amylase and protease activity in the stimulated and unstimulated leaf glands of Pinguicula grandiflora, P. vulgaris, P. lusitanica, and P. caudata. Two gland types are present, stalked and sessile. The stalked glands bear a muco-polysaccharide secretion droplet, and are concerned with capture of the prey; the sessile glands are specialised for digestion. In unstimulated glands of both classes, acid phosphatase, esterase and ribonuclease activity is associated with the anticlinal walls of the head cells, which have a characteristic spongy inner surface, comparable with that of transfer cells. Acid phosphatase and esterase activity was also detected in the vacuoles of the head cells of the sessile glands. Substrate film tests showed that amylase is readily released from the stalked glands but not from the sessile ones, while in contrast proteolytic activity is mainly associated with the sessile glands.On stimulation by suitable nitrogenous materials, the glands begin to sectete fluid onto the leaf surface within 1 hr. During the process the enzymes held in the spongy walls are discharged, and activity is also lost from the intracellular sites in the sessile glands.Digestion on the leaf surface and resorption of the products has been followed autoradiographically after feeding of ¹⁴C-labelled protein. Within 2 hr, digestion products enter the leaf, and move towards the margin in the vascular system. Movement out of the leaf begins within 12 hr. Microautoradiographs showed a concentration of products around the bases of the sessile glands and in the cells of the gland head, showing that these glands are involved in resorption as well as secretion.A possible mechanism of gland function is discussed.     

日本血吸虫尾蚴的组织化学及扫描电镜观察

日本血吸虫尾蚴具有一个头腺、2对前钻腺及3对后钻腺,其解剖学位置、构造、化学成分及功能均有区别。钻腺分泌物含有多糖酶及蛋白酶。尾蚴的前端系特化的头器结构,它具有半月形嵴、钻腺开口及乳突。     

Irradiation-induced effects on the innervation of rat salivary glands: Changes in enkephalin- and bombesin-like immunoreactivity in ganglionic cells and intraglandular nerve fibers

When treating head and neck for cancer with the use of radiotherapy the salivary glands are usually within the treatment volume with ensuing dryness and discomfort. Since the autonomic nervous system is of pivotal importance for the salivary gland function and integrity, the irradiation-induced effects may involve an influence on the innervation of salivary glands. Therefore, the rat submandibular gland, including the submandibular ganglionic cells, has been subjected to immunohistochemical examination with respect to expression of neuropeptides following fractionated irradiation with high energy photons. A markedly enhanced expression of bombesin- and leu-enkephalin-(ENK)-like immunoreactivities (LI) in the ganglionic cells and a pronounced increase in the number of nerve fibers showing these immunoreactivities in the submandibular gland tissue following irradiation were observed 10 days after treatment. On the other hand, no changes in the patterns of VIP (vasoactive intestinal polypeptide)- and NPY (neuropeptide Y)-immunoreactivities occurred. Thus, the present study shows that alterations in the expression of certain neuropeptides take place in the submandibular gland and its associated ganglionic cells in response to irradiation of the head and neck region. These changes may add further explanation to the inherent radiosensitivity of salivary glands.     

Histological study of the development of the embryo and early larva of Oreochromis niloticus (Pisces: Cichlidae)

The developmental stages of Oreochromis niloticus are similar to those described in other mouth-breeding tilapias except that, as in zebrafish, no cavity was found in the blastula. Variation in the rate of development of the embryo and larva of O. niloticus was found within a clutch of eggs as well as between clutches. Hatching glands are described for the first time in tilapias. They are widely distributed within the ectoderm covering the head, body, tail, and surface of the yolk sac near its attachment to the embryo. Timing of larval development is similar to that in other mouthbrooding tilapias, but is slower than that found in substrate-spawning tilapias. A pneumatic duct connects the swimbladder to the digestive tract and swimbladder inflation and initiation of feeding occurs at about the same time. The digestive tract of the larva 8 and 9 days after fertilization is similar to that found in the adult, except that there are no digestive glands. An endocrine pancreatic islet was first seen 76 h after fertilization. A prominent thymus gland is present at 100 h. Hematopoietic tissue develops in the vicinity of the pronephros during early larval development. A spleen develops later, 7 days after fertilization.     

The two origins of hemocytes in Drosophila

As in many other organisms, the blood of Drosophila consists of several types of hemocytes, which originate from the mesoderm. By lineage analyses of transplanted cells, we specified two separate anlagen that give rise to different populations of hemocytes: embryonic hemocytes and lymph gland hemocytes. The anlage of the embryonic hemocytes is restricted to a region within the head mesoderm between 70 and 80% egg length. In contrast to all other mesodermal cells, the cells of this anlage are already determined as hemocytes at the blastoderm stage. Unexpectedly, these hemocytes do not degenerate during late larval stages, but have the capacity to persist through metamorphosis and are still detectable in the adult fly. A second anlage, which gives rise to additional hemocytes at the onset of metamorphosis, is located within the thoracic mesoderm at 50 to 53% egg length. After transplantation within this region, clones were detected in the larval lymph glands. Labeled hemocytes are released by the lymph glands not before the late third larval instar. The anlage of these lymph gland-derived hemocytes is not determined at the blastoderm stage, as indicated by the overlap of clones with other tissues. Our analyses reveal that the hemocytes of pupae and adult flies consist of a mixture of embryonic hemocytes and lymph gland-derived hemocytes, originating from two distinct anlagen that are determined at different stages of development.     

Organ differentiation in newly hatched common wolffish

Wolffish Anarhichas lupus (Anarhichadidae) hatch from large demersal eggs (c. 5–6 mm) after a long incubation period (c. 800–1000 degree days) at 20–25 mm LT with a juvenile appearance: a small yolk sac, pigmented but partly transparent skin densely supplied with mucous cells, well developed body musculature and a cartilaginous skeleton. The results of histomorphological studies illustrate the apparent functionality of tissues and organs at hatching. The mucosa of the oral cavity and various parts of the digestive channel are well differentiated and the cellular characteristics are described within each region. A stomach with gastric glands is established before hatching. The pancreas has well developed endo- and exocrine tissue and the hepatocytes are vacuolized. The kidney tissue has numerous tubuli and haematopoietic tissue in the bilobed head region. The spleen, thymus and thyroid glands also appear mature. Cones are dominant in the visual cell layer of the retina.     

Observations on the buccal capsule and associated glands of adult Bunostomum trigonocephalum (nematoda)

Wilfred M. and Lee D. L. 1981. Observations on the buccal capsule and associated glands of adult Bunostomum trigonocephalum (Nematoda). International Journal for Parasitology11: 485–492. The buccal capsule or stoma of Bunostomum trigonocephalum is a large, cuticular-lined structure. The head of the nematode lacks distinct lips and has a large ovoid mouth which is partly occluded by a pair of sub-ventral cuticular plates which arise from the wall of the buccal cavity. A pair of sub-ventral lancets or basal onchia are situated at the base of the buccal cavity and a dorsal tooth arises from the base of the buccal cavity and extends forwards to terminate just inside the mouth. A duct lies within this dorsal tooth and extends from the ampulla of the dorsal oesophageal gland at the base of the tooth to open on the dorsal side of the tooth just below its sharp tip. A pair of muscles extends from the dorsal surface of the oesophagus to the base of the buccal capsule and are thought to bring about jerking movements of the head. Non-specific esterase and small amounts of acid phosphatase were detected in the oesophageal glands. Non-specific esterase and cholinesterase were detected in the large amphidial glands but not in the excretory glands. The possible role of the various structures and enzymes during feeding is discussed.     

Buccal glands of adults of the lamprey Mordacia mordax,including comparisons with other species

Mordacia mordax is one of the two anadromous parasitic lamprey species of the southern hemisphere family Mordaciidae. Its adults possess two lateral buccal glands and one central buccal gland. When the tongue-like piston is retracted, the buccal glands occupy much of the opening of the oral cavity at the rear of the buccal cavity. The glands contain numerous tube-like, ductless secretory units, which discharge directly into the buccal cavity. Their secretory epithelial cells contain numerous granules, some of which are zymogen-like, while others have a beaded, spiralled appearance. The similarity of the latter to mast cell granules suggests that they may likewise produce an anticoagulant, which would be valuable to a presumed blood feeder such as M. mordax. The mucus produced by these cells could act as a carrier for the secretions and as an adhesive for promoting retention of t he secretions on the host's surface. When the young adults is transferred to salt water, the buccal glands increase their production and discharge of secretions. Since the glands are not enclosed in musculature, their secretions are probably discharged by mechanical pressure applied by the forward movement of the head of the tooth-bearing piston into the buccal cavity. An account is given of the way in which the location, number, glandular organization, secretory granules, and type of secretion of the buccal glands of M. mordax, and thus presumably also their mode of function, differ markedly from those of members of the other lamprey family found in the southern hemisphere, and of all holarrctic lampreys. © 1995 Wiley-Liss, Inc.     

Cephalic anatomy of Sinentomon erythranum Yin (Protura : Sinentomidae)

The structure of the head capsule, endoskeletal structures, oral folds, mouthparts, foregut, maxillary and labial glands, and the central nervous system of the Chinese proturan Sinentomon erythranum Yin (Protura : Sinentomidae) have been described. The most significant features are the unusual thickness of the cuticle with numerous serrated lines, the reduction of sutures and the absence of linea ventralis, the simplification of gnathal pieces, and the reduction of the musculature. A comparison with other Protura and Apterygota leads to some morphological and phylogenetical interpretations of the cephalic structures, in particular those concerning the entotrophy.     

The mode of hatching of the monogenean Entobdella soleae, a skin parasite of the common sole (Solea solea).

Observations have been made on the hatching behaviour of the larva of the monogenean Entobdella soleae and on the effects of various enzymes on the opercular cement of the egg. These observations indicate that hatching is brought about by a proteolytic hatching fluid which is produced by two pairs of ventral head glands and spread over the inner surface of the opercular joint by rotation of the larva about its longitudinal axis. After hatching there is no trace of the ventral head glands. Similar glands are present before hatching in the oncomiracidium of E. hippoglossi.     

On approaches to the functional restoration of salivary glands damaged by radiation therapy for head and neck cancer,with a review of related aspects of salivary gland morphology and development

Radiation therapy for cancer of the head and neck can devastate the salivary glands and partially devitalize the mandible and maxilla. As a result, saliva production is drastically reduced and its quality adversely altered. Without diligent home and professional care, the teeth are subject to rapid destruction by caries, necessitating extractions with attendant high risk of necrosis of the supporting bone. Innovative techniques in delivery of radiation therapy and administration of drugs that selectively protect normal tissues can reduce significantly the radiation effects on salivary glands. Nonetheless, many patients still suffer severe oral dryness. I review here the functional morphology and development of salivary glands as these relate to approaches to preventing and restoring radiation-induced loss of salivary function. The acinar cells are responsible for most of the fluid and organic material in saliva, while the larger ducts influence the inorganic content. A central theme of this review is the extent to which the several types of epithelial cells in salivary glands may be pluripotential and the circumstances that may influence their ability to replace cells that have been lost or functionally inactivated due to the effects of radiation. The evidence suggests that the highly differentiated cells of the acini and large ducts of mature glands can replace themselves except when the respective pools of available cells are greatly diminished via apoptosis or necrosis owing to severely stressful events. Under the latter circumstances, relatively undifferentiated cells in the intercalated ducts proliferate and redifferentiate as may be required to replenish the depleted pools. It is likely that some, if not many, acinar cells may de-differentiate into intercalated duct-like cells and thus add to the pool of progenitor cells in such situations. If the stress is heavy doses of radiation, however, the result is not only the death of acinar cells, but also a marked decline in functional differentiation and proliferative capacity of all of the surviving cells, including those with progenitor capability. Restoration of gland function, therefore, seems to require increasing the secretory capacity of the surviving cells, or replacing the acinar cells and their progenitors either in the existing gland remnants or with artificial glands.     

Uncovering head gland diversity in neotropical Polistinae wasps (Hymenoptera,Vespidae): Comparative analysis and description of new glands

Exocrine glands are involved in several wasp colony activities; however, the number of known glands in the Vespidae is rather low when compared to other social insect groups. The aim of this study is to survey the head of Neotropical social wasps and to provide a detailed comparative study of the glands found in the Polistinae. A total of 33 species distributed over 13 genera were studied with serial histological sections of the head, excluding the labiomaxillary complex. Additionally, the exoskeleton was explored using scanning electron microscopy looking for associated modifications. A total of eleven exocrine glands were observed, five are structures recorded for the first time for the Hymenoptera, three are new records for the Polistinae and three are previously known organs. The glands studied are: ocellar gland I, ocellar gland II, periocular gland, subantennal gland, hypopharyngeal gland, clypeal gland, posterobasal genal gland, ectal mandibular gland, mesal mandibular gland, intramandibular gland I, and intramandibular gland II. The widespread distribution of most of these glands suggests an origin prior to the evolution of the Polistinae. Our results highlight the importance of detailed morphological studies to unveil the significance of chemical communication in one of the most characteristic groups of social animals.     

Proximate factors influencing soldier development in the basal termite <Emphasis Type="Italic">Cryptotermes secundus</Emphasis> (Hill)

Summary Regulation of soldier development in termites at the endocrinological and social scale was intensively studied in the 60s and 70s, but conclusive results are still scanty. In termites, the presence of soldiers inhibits further soldier differentiation, but the mechanism is not well understood. Secretions from the frontal glands seem to be important, but dry- and dampwood termites do not have frontal glands. We investigated the influence of precocene I, a JH-antagonist, and of soldier head extracts on the development of soldiers in the drywood termite, Cryptotermes secundus (Hill). Soldierless colonies produced fewer soldiers when treated with precocene I or soldier head extract than control colonies. Furthermore, colonies treated with precocene I had produced worker-nymph intercastes, last stage nymphs and alates by the end of the experiment (after six months) which were not present in control colonies. Hence, both treatments inhibited soldier development while precocene I simultaneously promoted the development of adult traits, probably by reducing (directly or indirectly) the JH level. The inhibition effect of the soldier head extract indicates that at least in termites without a frontal gland, other sources of material in the head have a regulatory function.     

Permeability of Oral Tissues to Blood-borne Coxsackievirus B-1

The ability of coxsackievirus B-1 to pass the barriers of the circulatory system into whole saliva has been shown previously. In this investigation, the major salivary glands and the oral mucosa were studied, and their role as participants in the excretion of coxsackievirus B-1 during viremia was evaluated. The effect of the salivary-gland stimulant pilocarpine nitrate on both the salivary flow rate and the recovery of virus during viremia was determined. A comparison was made between the amount of virus recovered from whole saliva during viremia in animals deficient in one or both of the major salivary-gland pairs and animals with a complete complement of salivary glands. The salivary glands in other animals were cannulated, and pure glandular secretions were collected during viremia and assayed for the presence of virus The amount of virus passing from the capillaries of the oral mucosa to the surface was also determined to evaluate this route as a possible site for the excretion of virus into saliva during viremia. The major salivary glands did not excrete appreciable quantities of virus during viremia. The submaxillary-gland secretions did not contain virus, and the parotid-gland secretions showed virus only at extremely high blood virus levels. Either removal of the major salivary glands or decreased salivary flow rates increased the concentration of virus in whole saliva. This observation suggested that the production of saliva by the major salivary glands tends to dilute the virus in the oral cavity. A 0.88-cm² sample of the oral mucosa excreted significantly large amounts of virus during viremia and suggested that the passage of virus through the oral mucosa was the major route for the excretion of virus into saliva during viremia.     

IKKβ overexpression leads to pathologic lesions in stratified epithelia and exocrine glands and to tumoral transformation of oral epithelia

Alterations in nuclear factor kappaB (NFκB) signaling have been related with several diseases and importantly also with cancer. Different animal models with increased or diminished NFκB signaling have shown that NFκB subunits and their regulators are relevant to the pathophysiology of different organs and tissues. In particular, both the deletion of the regulatory subunit β of the kinase of the inhibitor of NFκB (IKKβ) and its overexpression in epidermis lead to the development of skin inflammatory diseases not associated with tumoral lesions. In this work, we have studied the consequences of IKKβ overexpression in other organs and tissues. We found that elevated IKKβ levels led to altered development and functionality of exocrine glands (i.e., mammary glands) in transgenic female mice. In oral epithelia, increased IKKβ expression produced lichenoid inflammation with abundant granulocytes, macrophages, and B cells, among other inflammatory cells. This inflammatory phenotype was associated with high incidence of tumoral lesions in oral epithelia, contrary to what was found in skin. Moreover, IKKβ also increased the malignant progression of both spontaneous and experimentally induced oral tumors. These results highlight the importance of IKKβ in epithelial and glandular homeostasis as well as in oral tumorigenesis and open the possibility that IKKβ activity might be implicated in the development of oral cancer in humans.     

First molecular phylogeny of the major clades of Pseudoscorpiones (Arthropoda: Chelicerata)

The phylogenetic relationships of the major lineages of the arachnid order Pseudoscorpiones are investigated for the first time using molecular sequence data from two nuclear ribosomal genes and one mitochondrial protein-encoding gene. The data were analyzed using a dynamic homology approach with the new program POY v.4 under parsimony as the optimality criterion. The data show monophyly of Pseudoscorpiones as well as many of its superfamilies (Feaelloidea, Chthonioidea, Cheiridioidea and Sternophoroidea), but not for Neobisiodea or Garypoidea. Cheliferoidea was not monophyletic either due to the position of Neochelanops, which grouped with some garypoids. In all the analyses, Feaelloidea constituted the sister group to all other pseudoscorpions; Chthonioidea is the sister group to the remaining families, which constitute the group Iocheirata sensu Harvey--a clade including pseudoscorpions with venom glands within the pedipalpal fingers. This phylogenetic pattern suggests that venom glands evolved just once within this order of arachnids.     

Male accessory gland substances and the control of sexual receptivity in female Culex tarsalis

ABSTRACT. Homogenates of accessory glands from male Culex tarsalis Coquillet (Diptera; Culicidae) were fractionated using gel filtration column chromatography. A component of low molecular weight capable of suppressing female sexual receptivity was obtained and partially characterized. Proteins present in homogenates of isolated accessory glands formed aggregates with other proteins in extracts of whole mosquitoes. Consequently, previous reports of the molecular weight of biologically active components in homogenates from accessory glands from other mosquito species may be inaccurate.
When female Cx. tarsalis were mated with ³H-leucine labelled males. radioactivity could be found throughout the body of the female 24 h after mating. Autoradiography showed that the radioactivity was incorporated into the cells of various organs, and was not specifically localized in a particular target tissue. Approximately 30% of the total radioactivity transferred to the female was found in the head and thoracic regions, and proteins from the head had a specific activity twice that of the thoracic proteins. Bioassay of isolated body parts from mated and virgin females showed that injections of head tissues from mated females into virgin females suppressed sexual receptivity. These results suggest that the head is involved in the physiological mechanisms resulting in refractory mating behaviour.     

The Cardiogastric Gland and Alimentary Tract of Caenolestid Marsupials

The stomach of the South American marsupial family Caenolestidae has a gland on its lesser curvature around the cardia. This cardiogastric gland is bi-lobed, typically 11times5 mm and bears a distinctive, highly folded mucosa which forms sac-like invaginations. These open into the stomach lumen via 40–60 slit-like orifices. The gland mucosa contains unbranched gastric glands which are considerably longer than those of other gastric glands present elsewhere in the stomach. The cells within the cardiogastric gland show intense eosinophilic staining properties, with the parietal cells being larger than those found in other regions of the stomach, as well as being arranged in clusters. Argentaffin cells are not present in the stomach mucosa. The gross morphology of the stomach and intestine is similar to that found in small carnivorous marsupials.     

The salivary glands of Aparallactinae (Golubridae) and the venom glands of Elaps (Elapidae) in relation to the taxonomic status of this genus

The venom glands of four specimens of Elaps lacteus were examined and found to be structurally similar to the glands of other Elapidae and consequently different from the variable glands of the colubrid Aparallactinae, Lycophidinae and Dispholidinae. The recently proposed removal of Elaps from the Elapidae and its inclusion in the Aparallactinae (McDowell, 1968) is discussed, and the conclusion is reached that Elaps should remain within the Elapidae.