Morphology of the foveal glands and foveae dorsales in male Hyalomma truncatum and Rhipicephalus evertsi mimeticus ticks (Acari; Ixodidae) before and during feeding

The ultrastructure of the foveae dorsales and foveal glands in unfed and attached male Hyalomma truncatum and Rhipicephalus evertsi mimeticus ticks was studied. Both species are provided with a paired foveal gland system, which is similar in unfed as well as in attached ticks. This gland system consists of the fovea dorsalis with pores and pore tubes as the external part, the foveal neck zone as a link between the fovea dorsalis and the lobes of the gland and the bulbous lobes as the innermost part. The fovea dorsalis is located on either side of the dorsal midline in the midsection of the body and appears as a roundish plate containing 15±6.5 and 21±7 slit-like pores in R. evertsi mimeticus (n=210) and H. truncatum (n=210), respectively. Each pore leads into a cuticular lined channel containing a pore tube. Below each fovea, the foveal neck zone is located within a groove of the cuticle and consists of the termini of the pore tubes which enlarge basally to form a cup-shaped ampulla each. Furthermore, secretory lobes are located below the foveal neck zone. Each lobe consists of secretory cells and a central excretory duct which leads into the ampulla. The ducts are lined with microvilli. The secretory cells contain numerous vesicles of varying size with one or more granules. In male ticks of both species the secretory lobe cells remained unchanged in size, structure and granule content irrespective of whether they were unfed or attached for up to 30 days. Axons occur in the fascicles between the secretory lobe cells containing numerous neurosecretory vesicles. A possible role of the foveal glands in the production of pheromones is hypothesized.     

Morphology of the anterior digestive system of tonnoideans (Gastropoda: Caenogastropoda) with an emphasis on the foregut glands

ABSTRACT

Tonnoideans are marine carnivorous caenogastropods that prey on different invertebrates, namely polychaetes, sipunculids, bivalve and gastropod molluscs, and echinoderms. The morphology of the digestive system of 20 species from five families of the Tonnoidea was examined (for most of these species for the first time), and the salivary glands of six of them were studied using serial histological sections. Most of the studied families are rather similar anatomically, except Personidae (Distorsio), which differs both in proboscis morphology and the structure of the salivary glands. In most tonnoideans the salivary glands are split morphologically and functionally into anterior and posterior lobes, the latter synthesising strong sulfuric acid. The ducts of the posterior lobes are lined with non-ciliated epithelium and receive usually paired ciliated ducts from the anterior lobes to form a non-ciliated common duct, opening into the buccal cavity. In Personidae, the salivary glands are not separated into lobes, but are instead composed of ramifying tubules that are histologically different in the proximal and distal parts. Radulae of Tonnoidea are rather variable, with different patterns of interlocking teeth, both in the transverse and longitudinal rows, which may be related to particular feeding mechanisms. Due to the peculiarities of Personidae, the close relationship between that family and the rest of the Tonnoidea is questioned.     

Sizes and numbers of nuclei in the cortex of thymus glands of red-billed weavers Quelea quelea

The cortex of the thymus glands of embryos, chicks, juveniles, fledglings and adults from several colonies of Quelea quelea were studied using an image analyser (Quantimet 720) to determine cell populations and nuclear sizes. Just prior to hatching the lobes showed a high level of mitosis and consisted of predominantly small lymphocytes. The larger glands of chicks and juveniles had higher cell populations; pyknotic cells and erythrocytes occurred free in the cortex. The lobes of adults were more variable but in general mitosis occurred in enlarging glands of adults from colonies with eggs; most lobes contained pyknotic cells but not in such high numbers as in lobes from chicks and fledglings. Erythrocytes were common, occurring in large numbers in the cortex in some birds. The factors affecting the interpretation of these data are discussed in detail.     

Structure and development of bracteal nectary glands in Aphelandra (Acanthaceae)

A survey of bracteal (extrafloral) nectaries in species of Aphelandra (Acanthaceae) reveals substantial diversity. Each bracteal nectary is an aggregate of individual glands that vary in number, size, and structure among species. Glands contain three cell layers: a palisade-like secretory cell layer, a one-to-many-celled intermediate layer with thickened cell walls, and a foot layer. Members of the A. pulcherrima complex have one of two distinct gland types: relatively small glands with a single-celled intermediate layer or larger glands that have a multicellular intermediate layer. Nectaries composed of small glands are patches of many (>50) glands, whereas those composed of large glands are patches of < 10 glands. Four outgroup species have bracteal nectaries of numerous small glands with pluricellular intermediate layers. Glands of all three types are initiated as single enlarged protodermal cells, and all undergo similar early periclinal divisions; the large-gland type shows greater subsequent enlargement with many more anticlinal divisions. The bracteal nectar glands are interpreted to be homologous with simpler glandular trichomes, and mark a monophyletic lineage within Aphelandra. Comparisons with outgroup species show that both nectary types in the A. pulcherrima complex have diverged from an ancestral condition of numerous small glands with pluricellular intermediate layers. Use of the ontogenetic criterion to polarize gland type within the A. pulcherrima complex would yield erroneous results because evolution has apparently involved a developmental truncation with loss of cell divisions in the intermediate layer of small glands. Comparable nectar glands in more distant taxa are interpreted as remarkable cases of convergent evolution, perhaps from similar trichome precursors.     

Immunolocalization of Na/K–ATPase and Na/K/2Cl cotransporter in the tubular epithelia of sea snake salt glands

The sublingual salt gland is the primary site of salt excretion in sea snakes; however, little is known about the mechanisms mediating ion excretion. Na⁺/K⁺–ATPase (NKA) and Na⁺/K⁺/2Cl⁻ cotransporter (NKCC) are two proteins known to regulate membrane potential and drive salt secretion in most vertebrate secretory cells. We hypothesized that NKA and NKCC would localize to the basolateral membranes of the principal cells comprising the tubular epithelia of sea snake salt glands. Although there is evidence of NKA activity in salt glands from several species of sea snake, the localization of NKA and NKCC and other potential ion transporters remains unstudied. Using histology and immunohistochemistry, we localized NKA and NKCC in salt glands from three species of laticaudine sea snake: Laticauda semifasciata, L. laticaudata, and L. colubrina. Antibody specificity was confirmed using Western blots. The compound tubular glands of all three species were found to be composed of serous secretory epithelia, and NKA and NKCC were abundant in the basolateral membranes. These results are consistent with the morphology of secretory epithelia found in the rectal salt glands of marine elasmobranchs, the nasal glands of marine birds and the gills of teleost fishes, suggesting a similar function in regulating ion secretion.     

Comparative ultrastructure of the salivary glands of two phytopathogen vectors,the beet leafhopper,Circulifer tenellus (Baker), and the corn leafhopper,Dalbulus maidis DeLong and Wolcott (Homoptera : Cicadellidae)

The salivary glands of 2 leafhoppers, Circulifer tenellus and Dalbulus maidis (Homoptera : Cicadellidae) were examined by light and electron microscopy. Centrally located and occupying both the head and thorax, the salivary glands consist of 2 paired parts, the accessory glands and the principal glands. In C. tenellus and D. maidis, the accessory glands are large, multicelled lobes that lie anterior to the principal gland. They join the principal glands near the common salivary duct-gland junction via a thinner tubular duct. The principal glands of both species consist of large binucleate cells that differ in cytology and arrangement. These cells are easily distinguished by unique staining characteristics. Circulifer tenellus salivary gland cells are arranged in 2 lobes, the anterior lobe, made up of 3 concentric rings around the salivary duct and the posterior lobe, arranged in a loose pyramid extending above the foregut. Dalbulus maidis glands are similarly organized around the salivary duct.     

大腹园蛛丝腺及其细胞形态的初步观察

运用显微解剖和石蜡切片技术,我们首次对大腹园蛛Araneus ventricosus腹部的5种丝腺的形态进行了分离、拍照和切片观察.研究发现壶状腺腹腔较大,有多根纺管;梨状腺为多细胞腺体、成簇;集合腺有不规则的分支,纺管外附着小结节;葡萄状腺成簇.各类型丝腺腺体细胞明显可见,但未能明显见到不同丝腺腺体细胞的形态区别.同时也发现了几个存疑形态：壶状腺上附着的腺体、壶状腺下导管和壶状腺腺体细胞,它们可能与蜘蛛腺体的退化或发育等相关.     

Oviductal morphology and egg shelling in the oviparous lizards Crotaphytus collaris and Eumeces obsoletus

Morphological changes occurring in the oviduct and epithelial cells of the lizards Crotaphytus collaris and Eumeces obsoletus during the natural reproductive cycle were examined and quantified. Additionally, development of the eggshell at different stages of gravidity was described. The anterior uterus of each species has a distinct glandular type which differs between species: in E. obsoletus, the glands are tubular and in C. collaris, branched saccular. The branched saccular glands in the anterior uterus of C. collaris produce collagen-like material that forms the fibers of the shell membranes. However, fibers from the eggshell of E. obsoletus did not stain for collagen. The shell of both species is composed of a multilayered inner boundary covered externally by fibers of varying thickness. Initial layers are composed of thick fibers all lying along the same general axis. Outer layers of fibers are progressively thinner and an external surface layer composed of glycosaminoglycans (GAGs) is also present. In C. collaris, calcium, which is deposited in relatively small amounts on the shell surface, appears to be secreted by the epithelium of the anterior uterus. The nonciliated secretory epithelial cells covering the villi-like folds of the posterior infundibulum secrete GAGs. Epithelial cell height of the infundibular villi is greatest during early gravidity. A functional relationship may exist between luteal activity and oviductal secretory activity because the activity of the glandular epithelium varied as gravidity progressed.     

Parathyroid gland structure of some tropical lizards

The number, location, size, shape and microstructure of the parathyroid glands of Agama agama agama, Hemidactylus brooki angulatus and Pytodactylus hasselquisti hasselquisti was investigated using approximately 250 specimens of each species from the Zaria area of Nigeria. Only parathyroid III was found. Additional patches of tissue in Hemidactylus, though possibly parathyroid IV, are considered to be derived from parathyroid III. It was found that the amount of parathyroid tissue per gram of body weight was similar in the three species used, and that females had more parathyroid tissue than males. The same situation seems possible in other species. The structure of the parathyroid glands could not be related to taxonomic grouping within the Sauria, but the general picture was found to be more similar to that of birds and mammals than to that of amphibians.     

Species interactions and habitat associations of birds inhabiting urban areas of Sydney,Australia

Abstract The absence of small birds from many suburban areas may be due to adverse garden characteristics, interspecific aggression or human behaviour such as supplementary food provisioning that encourages predators. We investigated the relationship between these factors and the presence of seven small bird species in Sydney through a community‐based survey. The survey was conducted by participants over a 7‐day period between 7 am and 10 am in November and early December 2000. Three dominant species, the noisy miner (Manorina melanocephala), pied currawong (Strepera graculina) and common myna (Acridotheres tristis) were each present in over 59% of gardens. Each small bird species was present in less than 40% of gardens. All small birds were negatively associated with noisy miners, but only the silvereye (Zosterops lateralis) was negatively associated with pied currawongs. None of the species of small birds was negatively associated with common mynas. Four species of small birds were associated with at least one habitat variable, notably the proportion of native vegetation. Although more birds were recorded in gardens in which meat was provided, there were significantly fewer small birds in these gardens. There were also more birds recorded in gardens where seed was provided, with red‐browed finches (Neochmia temporalis) positively associated with seed provisioning in most regions of Sydney. The presence of dogs and cats was not related to the total abundance of birds overall or small birds in gardens. While garden characteristics may influence the presence of small birds to some degree, the presence of noisy miners, a species that are thought to aggressively exclude other species from their territories, is likely to be an important influence on these species in suburban areas. Furthermore, supplementary feeding by people is likely to negatively influence some small birds. The presence of carnivorous pets does not seem to influence the presence of small birds at the scale of the individual garden.     

Comparative study of the digestive system of three species of tinamou. I. Crypturellus tataupa,Nothoprocta cinerascens,and Nothura maculosa (Aves: Tinamidae)

The morphology and histology, as well as the cytochemistry of complex carbohydrates, of the digestive system of Crypturellus tataupa (tataupa tinamou), Nothoprocta cinerascens (brushland tinamou), and Nothura maculosa (spotted tinamou) are described. The general morphology of the digestive system of these birds follows the basic model of the avian alimentary canal, although statistical analysis shows that the lengths of the organs are significantly different among the species. From cephalic to caudal regions the alimentary tract consists of esophagus, ingluvies or crop, proventriculus or glandular stomach, ventriculus or muscular stomach, small intestine, well-developed ceca, and rectum. Histologically, each section of the tract consists of four primary tissue layers: mucosa, submucosa, muscularis, and adventitia. Variations are found in the thickness of the esophageal epithelium, which shows the highest value in C. tataupa. In the proventriculus, the depth of the compound glands is greatest in N. cinerascens. The villi of the epithelial cells in the small intestine are most extensively developed in C. tataupa. Heterogeneity of mucins is detected not only in the surface coat of the alimentary tract but in the cellular content of the glands as well. Comparisons with the morphology of the digestive system of closely related and more advanced birds are made, and the possible relationship between morphological and cytochemical variation and the diet is discussed. © 1996 Wiley-Liss, Inc.     

The morphology of the sex pheromone gland in Drosophila grimshawi

The morphology of a sex pheromone-producing gland found in the abdomen of Drosophila grimshawi males was studied by light and electron microscopy. This gland, consisting of two intra-anal lobes, contains cells that resemble those of other insect pheromone glands. However, in contrast to many other insect pheromone glands that release pheromone through the cuticle, cells of the intra-anal lobes secrete into a canaliculi-duct system that empties into the anal region. The liquid secretory product flows along the surface of the intra-anal lobes and is brushed onto the substrate by fingerlike projections on the lobes' surfaces.     

Salivary glands in Cicadidae (Hemiptera: Cicadoidea): comparative morphology, ultrastructure, and their phylogenetic significance

The present investigation provides information on gross morphology and ultrastructure of salivary glands of species in Cicadidae in detail. The structure of the salivary glands of 11 representative species from 10 genera belonging to three subfamilies of Cicadidae was studied using light microscopy and transmission electron microscopy. In the examined species, the salivary glands are paired structures, and each of which is comprised of a principal gland (pg) and an accessory gland (ag). The pg is divided into anterior and posterior lobes, and both of which consist of numerous long digitate lobules. The lobules at the base of the long digitate lobules of posterior lobe are greatly short; here, we named as “short lobules.” All the lobules vary in size, disposition, length, and shape. The anterior lobe and posterior lobes are connected by an anterior–posterior duct (apd). Two efferent salivary ducts (esd), derived from corresponding posterior lobes, fuse to form a short common duct which enters into the saliva syringe. The ag is composed of a greatly tortuous and folded accessory salivary tube, a gular gland (gg) constituting of several acini, and an accessory salivary duct (asd). The asd joins the esd at the place where the latter emergences. Constituents and arrangement of the salivary glands, the number and shape of the long digitate lobules in the anterior and posterior lobes, and the visibility of the apd were promising characters for the taxonomic and phylogenetic analysis of Cicadoidea. The variations of secretory granules in size, shape, and electron density in lobule cells of pg of Platypleura kaempferi probably indicating different materials are synthesized. The absence of the infoldings of basal plasma membrane in the basal area of the cells and the presence of electron-lucent vesicles in the cytoplasm of the gg cells of P. kaempferi might suggest that the secretions of gg are more watery.     

Diversity of feeding adaptations in certain columbid birds: A functional morphological approach

With gradual increasing complexity in higher vertebrate structure and function, the birds as a class have acquired very high degree of feeding adaptations for diverse food-niches. A comparative functional morphological study of the feeding apparatus of 6 species of columbid birds showing diversification in their food-habits reveals that some correlations exist between the form-function complexes of the feeding apparatus and the extent of diversity of food-habits shown by these birds. Among the species of columbid birds selected for the Study,Columba andStreptopelia are ground feeders and predominantly grain-eaters, although quite often they invade diversified food-niches.Treron andDucula, on the other hand, are almost exclusively fruit-eaters, plucking and swallowing fruits from the lofty tree branches, WhileColumba andStreptopelia show better kinesis of their jaws for ground-pecking,Treron. andDucula possess wider gape as well as stronger grasp of their bill for plucking off, grasping and swallowing large-sized fruits. Consequently, the size and pinnateness of the jaw muscles in these fruit-pigeons have developed far greater than those observed inColumba andStreptopelia. Further, inTreron andDucula, the thick and broad ‘venter externus’ slip of the M. pterygoideus ensures complete closure of the bill and possibly prevent any excess lateral expansion of the mandibular rami. Similar correlations have also been observed between the tongue features of columbid birds and the diversity of their feeding adaptation.     

Distribution of specific proteins in the salivary gland lobes of Culicidae and their relation to age and blood sucking

Specific proteins are produced in different parts of the salivary glands of female Anopheles and Culex. In both species there are concentrated low molecular weight proteins in the median lobes and proteins in the mol. wt range 25,000–60,000 in the distal parts of the lateral lobes. These proteins are not identical in the two species. In the proximal parts of the lateral lobe there are only small amounts of protein in addition to an unknown high molecular weight substance. At the time of blood-sucking 15–35% of soluble gland proteins are injected with the saliva into the host animal, the proteins from the median lobes and the proximal part of the lateral lobes being released in greater quantities than the proteins from the distal parts of the lateral lobes. The typical gland proteins are only extractable in low concentrations from the salivary glands of the newly-hatched adult mosquito, they increase up to the 7th day of the adult development and are stored in the glands.     

The homology of cranial glands in turtles: with special reference to the nomenclature of salt glands

The cranial glands of ten species of turtles were studied by the use of histochemistry applied to serial sections of whole heads. The majority were stenohaline species, but one brackish water form, Malaclemys, was included. The results show that all species have two major orbital glands, an anterior Harderian gland, and a posterior lachrymal gland. The latter is seromucous in all species except Malaclemys terrapin in which the gland shows little evidence or organic secretion. External and medial nasal glands are found in all species studied, and also are seromucous glands. With these reslts, combined with a review of the literature the following conclusions are made. The Harderian gland is by definition the orbital gland opening through the medial surface of the nictitating membrane at or near the anterior canthus. It is of constant occurrence, and histological appearance, probably serving the same function. However, despite much recent study this function remains unknown. The lachrymal gland is defined as the orbital gland which opens through the lateral surface of the nictitating membrane, or medial surface of the lower eyelid, at or near the posterior canthus. It is of variable occurrence, absent in many reptiles, and has a histological structure which is also variable. In the stenohaline species it is apparently involved in organic secretion, while in the brackish water Malaclemys it may be involved in salt secretion, as it is in Cheloniidae. The nasal glands in turtles are probably homologous with the nasal salt glands of lizards and birds, but they do not appear to subserve the same function. In all species of turtles studied the nasal glands are seromucous. They are perhaps involved in the maintenance of the epithelium of the olfactory cavity.     

Salt glands of Armeria canescens (Host) Boiss.: Morphological and functional aspects

The morphology and functionality of salt glands in four Italian Armeria canescens populations were investigated. Microscopic analysis showed that salt glands consist of 16 cells arranged in four quadrants, including four subsidiary cells and 12 gland cells. The main secreted elements are K, Ca and Cl, although qualitative and quantitative differences were observed between gland and subsidiary cells. Soil characteristics like texture, pH and C/N ratio were shown to vary between population sites. The highest number of glands per leaf area was found in plants from Ca-rich sites. Although A. canescens is not a halophilous species, its salt glands were revealed to be active, suggesting that they could represent an ancestral character.     

Unusual labial glands in snakes of the genus Geophis Wagler, 1830 (Serpentes: Dipsadinae)

Geophis belongs to the goo‐eating dipsadine assemblage of snakes that are known to feed exclusively on earthworms, snails, and slugs. Although the unusual feeding strategies of the goo‐eating dipsadines are well known (but poorly documented), little attention has been paid to their internal anatomy. Here, we describe a new and noteworthy morphological and histochemical condition of the infralabial glands in three species of Geophis (G. brachycephalus, G. nasalis and G. semidoliatus), all earthworm feeders. Their infralabial glands are constituted of two distinct parts: an anterolateral portion composed of mucous and seromucous cells that stretches from the tip of the dentary to the corner of the mouth, and a tubular posteromedial portion that is exclusively seromucous. The anterolateral portion receives fibers of the levator anguli oris muscle that attaches on its posterodorsal extremity while the posteromedial portion extends posteriorly to the corner of the mouth where it receives fibers of the adductor mandibulae externus medialis muscle. Furthermore, the posteromedial portion of the infralabial gland is constituted by large acini filled with secretion that is periodic acid‐Schiff positive. These acini release their secretion directly into a large lumen located in the middle of the glandular portion. In the three species examined, the supralabial glands show a traditional configuration, being constituted of mucous and seromucous cells and retaining an enlarged part in its caudal region that resembles a Duvernoy's gland. The presence in Geophis of an expanded lumen in part of the infralabial gland that is compressed by an adjacent muscle suggests a more specialized role for the secretion produced by these glands that may not be related to envenomation but rather to prey transport and mucus control. J. Morphol. 275:87–99, 2014. © 2013 Wiley Periodicals, Inc.