The skin of primates. XXXVI. The skin of the pigmy marmoset--Callithrix (Cebuella) pygmae

The pigmy marmoset — Callithrix (= Cebuella) pygmaea Spix — is the second detailed study of the members of the family Callithricidae. It is closely allied to the red-mantled tamarin — Saguinus (=Tamarinus) fuscicollis illigeri Spix — and shares some of its characteristics with both Prosimii and Anthropoidea. The epidermis and dermis contain moderate numbers of concurrent, melanotic melanocytes. The dermis is rich in elastin. Hair follicles grow in groups of three or four over the general body surface, and one apocrine gland is associated with each grouping. Arrectores pilorum muscles are well developed. On the ventral ulnar wrist are sinus hairs associated with apocrine glands. Most hair follicles have nerve end-organs around them that are reactive for acetylcholinesterase and alkaline phosphatase. There is a large aggregation of sebaceous glands in the suprapubic region. The large sebaceous glands in the eyelid, face, and external genitalia are surrounded by cholinesterasereactive nerves. Apocrine glands are found over most of the hairy skin except the brow, scalp and back; a large grouping of them is present in the sternal region. Only the secretory coils of apocrine glands in the external genitalia are invested with butyrylcholinesterase-rich nerves. Eccrine glands are confined to the volar surfaces of the pes and manus. They have dark cells with abundant glycogen and clear cells with neither glycogen nor PAS-reactive material. The nerves around the eccrine secretory coil are reactive only for acetylcholinesterase.     

The skin of primates. XLI. The skin of the silver marmoset—Callithrix (= Mico) Argentata

The skin of the silver marmoset, Callithrix (= Mico) argentata Linnaeus, has many outstanding characteristics. The unusually thin epidermis and dermis are generally devoid of melanotic melanocytes. The surface of the interramal gular region is peppered with small, elevated papillae; that of the corpus penis is characterized by keratinized, proximally directed hollow spines in whose cavities are organized nerve end-organs and capillary loops. Cholinesterase-reactive papillary nerve end-organs and Meissner corpuscles populate all volar friction surfaces. A highly vascular dermis and subcutaneous fat pad partially contribute to the characteristic rubicund color of the face, external ears, and anogenital region. Many body surface hairs are accompanied by the classic Haarscheibe of Pinkus. Sinus hairs are plentiful; a circumscribed vibrissa-bearing eminence is located on the ventral ulnar aspect of each wrist. Alkaline phosphatase-positive, stellate-shaped cells are found on the outer root sheath and epithelial sac of active and quiescent hairs in all cephalic regions; such cells are not argyrophilic, aurophilic, or osmiophilic. Hairs grow in linear perfect sets of 3 to 5 follicles; they do not grow singly on the cheek. Large sebaceous glands contain alkaline phosphatase in their peripheral acini; extensive fields of gigantic multilobular sebaceous glands contribute to the distinct, opaque-white color of the scrotal skin. Numbers of apocrine sweat glands are diminished in cephalic regions but one gland occurs with each hair follicle in the axilla, scrotum, suprapubic region, and ulnar eminence. Relatively avascular eccrine sweat glands are confined to the volar friction surfaces. Their secretory coils contain sporadically distributed glycogen and phosphorylase and surrounding nerves are much more reactive for acetyl- than butyrylcholinesterase.     

The skin of primates. XXXVII. The skin of the pig-tail macaque (Macaca nemestrina)

The skin of the pig-tail macaque is basically similar to that of the rhesus monkey and the stump-tail macaque. The epidermis is thin and contains occasional basal melanocytes. The dermis, rich in elastic fibers, is practically free of pigment-containing cells. The upper dermis is highly vascular in the perianal region and sex skin. Cholinesterase-reactive nerve endings are plentiful beneath the friction surfaces of the pes and manus, mucous membranes, and junction of the hairy gluteus and glabrous ischial callosity. Hederiform-like endings are present in the eyelid, pinna, and frontal scalp. Apocrine and eccrine sweat glands occur throughout the hairy skin in a 2–3: 1 ratio. Both types are invested by nerves reactive for acetyl- and butyrylcholinesterase.     

The skin of primates. XL. The skin of the cottontop pinché Saguinus (=Oedipomidas) oedipus

The skin of Saguinus (= Oedipomidas) oedipus Linnaeus, is basically similar to that of the red-mantled tamarin, Saguinus (= Tamarinus) fuscicollis Spix; it has several peculiarities: (1) a circumscribed tuft of vibrissae on the ulnar aspect of the wrist; (2) an accumulation of apocrine glands over the sternum; and (3) an extensive posterior abdominal field of gigantic sebaceous glands admixed with large apocrine glands, better developed in the female. The epidermis, dermis, hair follicles, sebaceous ducts, and apocrine excretory ducts are all heavily pigmented. Hairs are arranged in linear perfect sets; the epithelial sac of quiescent follicles is devoid of glycogen and phosphorylase. Eccrine sweat glands are restricted to the volar friction surfaces and contain no glycogen. Only the coiled excretory ducts of the eccrine glands contain phosphorylase. All cutaneous nerve fibers are more reactive for acetylthan butyrylcholinesterase.     

The skin of primates. 38. The skin of the red uacari (Cacajao rubicundus)

The skin of the red uacari (Cacajao rubicundus) is characterized by distinctive traits. Pigmentation of both the epidermis and dermis in juvenile animals resembles a similar condition recorded in adult Callithricidae. Extensive capillary sinuses pervade the upper dermis of the face, ears, forehead, and frontal scalp. Hederiform nerve endings are common in the face and scalp, as are papillary nerve endorgans in the volar friction surfaces; both are reactive for specific and pseudocholinesterase. A general diminution in size of hair follicles and a retarded generative cycle contribute to the phenomenon of “baldness” in the forehead and scalp of mature animals. Apocrine glands are quantitatively diminished over the dorsum. Eccrine sweat glands, confined to the palmar and plantar friction surfaces, are poorly differentiated; all secretory cells contain glycogen.     

Three types of cutaneous glands in the skin of the salamandrid Pleurodeles waltl. A histological and ultrastructural study

Histological and ultrastructural investigations revealed three different multicellular skin gland types in the salamandrid Pleurodeles waltl. The mucous glands are small, with one layer of secretory cells surrounding a central lumen; they produce the viscous and slippery mucus film that has various functions in amphibians. The serous glands can be divided based on their histological and ultrastructural characters into the granular gland Type I (GGI) and the granular gland Type II (GGII). The first type (GGI) is moderately sized and distributed throughout the body surface, with higher concentrations in the parotoid and back regions. In contrast, the second type (GGII) is very large (for Pleurodeles) and was found only in the tail, with highest concentration in the tail dorsum. Both granular gland types contain mainly proteinaceous materials but differ in their morphological features including size, shape, cellular organization and vesicle distribution, vesicle size and vesicle shape. Both GGI and GGII are especially concentrated in body parts that are presented to an attacking predator and are hypothesized to produce repellent to poisonous substances to thwart potential aggressors. J. Morphol., 2009. © 2009 Wiley‐Liss, Inc.     

The skin of primates. XXXIX. The skin of the white-browed capuchin (Cebus albifrons)

The skin of the white-browed capuchin (Cebus albifrons), although basically similar to that of the squirrel monkey (Saimiri sciureus), contains several outstanding peculiarities: (1) both the epidermis and dermis of the general body surface are devoid of melanotic melanocytes; (2) the skin of the prehensile tail has no modified, glabrous friction surface; (3) the prehensile surface of the tail has no specialized nerve end-organs; (4) cholinesterase-positive, papillary nerve end-organs rest beneath the epidermal ridges of volar skin; and (5) both the clear cells and dark cells of the eccrine glands contain glycogen but neither shows phosphorylase activity.     

Melanin deposits associated with the venom glands of snakes

Melanin deposits in the heads of both true vipers (Viperinae) and pit vipers (Crotalinae) are concentrated over the dorsal and dorsolateral aspects of the venom glands. This pigment may occur in any or all of six sites which include the epidermis, dermis, tissues covering the venom glands, and the interior of the glands themselves. The extreme localization of these melanin deposits suggests that they shield the venom glands from light. Calculations indicate that without such shielding the light energy penetrating the venom glands in the visible and ultraviolet portions of the solar spectrum would damage the venom-synthesizing apparatus and detoxify stored venom. Elapid and hydrophiid snakes have less dense pigment over the venom gland than vipers. Literature reports indicate that elapid venom is less sensitive to photodetoxification than is venom from vipers. Most colubrid snakes, including several with protein-secreting Duvernoy's glands, have little or no melanin associated with the glands. Venomous colubrids in the genera Ahaetulla, Dryophis, Leptophis, and Oxybelis have pigment over the glands as dense as that seen in vipers. Iridophores probably also shield venom glands from radiation. In puff adders and Gaboon vipers (Bitis) there appears to be an ontogenetic change in the shielding of the venom glands from melanocytes in young individuals to iridophores in adults.     

The skin of primates. XXXIV. The skin of the golden spider monkey (Ateles geoffroyi)

The skin of the golden spider monkey (Ateles geoffroyi) has many histological and histochemical similarities to that of the woolly monkey (Lagothrix lagotricha) and howler monkey (Alouatta caraya); however, this monkey possesses certain peculiar properties such as large sebaceous glands, a combined distributional pattern of eccrine and apocrine sweat glands, and abundant alkaline phosphatase in the sebaceous glands, apocrine and eccrine sweat glands. In brief, the anatomical and histochemical properties of the skin of this animal are more similar to those of the howler monkey than to the woolly monkey. In addition, the skin of these three Ceboids falls phylogenetically between that of the Cercopithecoidea and Pithecoidea.     

Testicular and androgen dependence of skin gland morphology in the anurans,Xenopus laevis and Rana pipiens

In anuran amphibians, there is increasing evidence that exocrine glands dispersed throughout the general integument are secondary sex characters (SSC). Following the recent discovery of sexually dimorphic “breeding glands” in the dorsum of male Rana pipiens, we studied the effects of castration and testosterone treatment on the dorsal skin glands of male Xenopus laevis and R. pipiens to determine whether the dorsal breeding glands, or any other dorsal skin glands, are androgen dependent. The dorsal skin glands of X. laevis were unaffected by androgen status. By contrast, in R. pipiens, breeding, mucous, and seromucous glands responded to testosterone stimulation. Mucous glands were significantly (P < 0.05) larger in testosterone-treated frogs than in castrates. There was a large, but statistically insignificant, increase in the size of the dorsal breeding glands. Testosterone treatment also increased the epithelial cell height of breeding and seromucous glands (P < 0.05). In the skins of castrated and testosterone-treated frogs, there was a reciprocal relationship between the abundance of seromucous and breeding glands: in castrates, seromucous glands were abundant and breeding glands virtually absent, whereas in testosterone-treated frogs, breeding glands were abundant and seromucous glands less common. The total number of the two gland types was similar in both treatment groups. Glands that appeared to be intermediate in form between seromucous and breeding glands were observed in some frogs. These data suggest that seromucous glands may be the regressed form of breeding glands in the dorsal skin of R. pipiens and that the dorsal skin of R. pipiens is a SSC. © 1993 Wiley-Liss, Inc.     

The skin of primates. XXIX. The skin of the pigmy bushbaby (Galago demidovii)

The skin of the pigmy bushbaby (Galago demidovii), the smallest existing prosimian, is largely similar to that of the other African Lorisidae, although this animal has certain peculiar features. The very thin epidermis contains alkaline phosphatase-reactive dendritic cells which resemble those in the other bushbabies and the potto. The hair follicles of this animal are similar to those of the lesser bushbaby, while the sebaceous glands are different from those of the other bushbabies in being reactive for alkaline phosphatase. The histological and histochemical properties of the sweat glands are similar to those of the other bushbabies.     

A histological study of cutaneous glands in the brown brocket deer

We examined the histological structure of 8 skin areas thought to contain cutaneous glands of potential importance in scent communication in 16 brown brocket deerMazama gouazoubira Fisher, 1814, using standard histological techniques. Frontal areas and preorbital sacs had scant glandular development. Sebaceous gland development was prominent in vestibular nasal glands and prepucial glands. Apocrine sudoriferous glands and sebaceous glands were well developed in tarsal glands, the caudal skin area and the interdigital glands of front and hind feet. The tail had a unique arrangement of apocrine sudoriferous glands. Anal glands had moderate glandular development, and metatarsal glands were absent. Several of these glandular areas may be important in the chemical communication among brocket deer.     

Histological observations on presumed electroreceptors and mechanoreceptors in the beak skin of the long-beaked echidna,Zaglossus bruijnii.

Sensory receptors in the rostral portion of the beak skin of a single specimen of the rare long-beaked echidna, Zaglossus bruijnii, are described. Mucous glands which have been modified to accommodate sensory innervation, similar to those seen in Ornithorhynchus, are found in the rostral 2 cm of the beak skin, anterior to the maxillofacial foramen, at a density of approximately 12/mm². The papillary epidermal portion of the gland ducts are walled by concentric layers of keratinocytes, and each duct is innervated by 10–15 myelinated nerve terminals. The mucous gland receptors in Zaglossus are intermediate in structure between those of Ornithorhynchus and Tachyglossus, but are similar enough to the former to suggest that electroreception may play a major role in the sensory experience of Zaglossus. Push-rod mechanoreceptors also occur throughout the same region of beak skin, and appear similar to those described for Tachyglossus.     

The development of the mucilage gland of two Japanese species ofAlaria

The genusAlaria possesses a structure known as the mucilage gland which appears mainly on the frond. This is also true ofUndaria. The mucilage gland ofUndaria usually originates from some of the epidermal cells. However, observations of plants ofAlaria at various stages indicate that glands originate not only in the surface layer. There are still other glands which are initiated by some cortical cells situated directly beneath the epidermis. In both, a refractive substance is gradually accumulated as these cells enlarge. The mucilage glands starting in the surface (the primary mucilage glands) resemble those ofUndaria in their development, whereas those in the cortex (the secondary mucilage glands) are quite analogous to the secretory cells ofLaminaria, etc., which secrete mucilage into a mucilage canal in the first stage. Thus,Alaria seems to constitute a link betweenUndaria andLaminaria, etc.     

The dorsal tail tubercle of Mertensiella caucasica and M. luschani (Amphibia: Salamandridae)

Males of the two species of Mertensiella (M. caucasica and M. luschani) possess a tubercle projecting from the skin of the dorsal tail base, the single morphological character that defines the genus. The dorsal tail tubercle functions during courtship, and its role is similar in both species. The tubercle is inserted into the cloaca of the female during ventral amplexus, shortly before the male deposits a spermatophore. Histological examination, however, revealed that the dorsal tubercles differ structurally between the two species. In M. caucasica, the tubercle consists primarily of elongate mucous glands, with granular glands occurring only at the base. Both mucous and granular glands of the tubercle are larger than those in typical skin. Unlike typical skin, however, mucous glands are larger than granular glands. In M. luschani, mucous glands and granular glands occur throughout the tubercle, and the granular glands are larger than the mucous glands, although both types are larger than those in typical skin. The dorsal tubercles of M. caucasica and M. luschani may not be homologous structures and may have resulted from convergent evolution. J Morphol 232:93–105, 1997. © 1997 Wiley-Liss, Inc.     

Effect of rat salivary glands extracts on the proliferation of cultured skin cells - a wound healing model

Objective: Salivary gland secretions play an important role in promotion of wound healing. The healing of intra- or extra-oral wounds is delayed in desalivated rats. However, the specific role of each salivary gland in promoting wound healing is unknown. This study was aimed to investigate the effect of crude extracts of rat salivary glands on a simplified in vitro wound healing model. Design/methods: Cultured human keratinocytes (HaCat) and murine fibroblasts (3T3) were subjected to 48 h serum starvation, and were later activated by extracts of rat salivary glands, 1–10 μg protein/ml of each gland. The resultant cellular metabolic activity of the activated cells was determined 24 h later, measuring reduction of XTT by mitochondrial enzymes, and calculated relatively to positive controls [optimal supplementation of 10% fetal calf serum (FCS)], and negative controls (starved non-supplemented cells). Results: The relative stimulatory effect of parotid (P) extract on the cells was significantly lower than either submandibular (SM) or sublingual (SL) extracts. Under the assumption that physiologically, the cells are exposed to the combined effect of saliva secreted from all the glands, different combinations of the extracts were presented to the cells. The relative stimulation was maximal following treatment with the three glands extracts (P + SM + SL) and exceeded the effect of 10% FCS. Conclusion: The results suggest that each salivary gland has a specific effect on wound healing and the combination of the three extracts has an additive effect but no the sum of all individual glands. This model might be useful to study the wound healing effect of salivary glands. In partial fulfillment of the requirement for MD thesis, The Joyce and Irving Goldman School of Medicine, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva, Israel.     

Fine structure of reproductive glands in two primitive marine pulmonates (Basommatophora: Siphonariidae)

Within the clade Euthyneura the marine basommatophorans are particularly neglected. More morphological and molecular studies are needed because their phylogenetic relationships with other pulmonates remain unresolved. The present study examines the most conspicuous reproductive gland, the glandular complex in two marine limpets, Siphonaria capensis and S. serrata (Pulmonata: Basommatophora) at both gross and fine structural levels. These two sympatric species with different developmental modes were selected to compare the structure and function of this enormous glandular structure. In both S. capensis and S. serrata, the glandular complex shows an undifferentiated state composed of an acidophilic albumen gland and a basophilic mucous gland. The glands contain secretory cells and supporting cells (= ciliated cells) that are highly ciliated. When the histochemical properties of the glandular complex were compared with those of siphonariid egg masses (of each species) it could be established that the albumen gland was responsible for the production of perivitelline fluid whereas the mucous gland secreted substances that help in the assembly of mucous layers surrounding the egg capsules. We suggest that the presence of a single glandular complex comprised of two glands is the most primitive organization of reproductive glands in pulmonates. Furthermore, the histology, fine structure and histochemistry of these glands are very similar to those of the reproductive glands of opisthobranchs.     

Honeybee glands as possible infection reservoirs of Nosema ceranae and Nosema apis in naturally infected forager bees

Aims: To determine whether Nosema ceranae and Nosema apis are present in different gland tissues of honeybee, Apis mellifera L. and to monitor spore presence and quantity in these glands in naturally infected hives from July 2009 to July 2010 in Quebec, Canada. Methods and Results: Nosema spp. were quantified using duplex quantitative real‐time PCR in the thoracic salivary, hypopharyngeal, mandibular glands, and venom sac and glands of A. mellifera over a period of 8 months. Both Nosema species were present in all the glands as single or mixed species; however, N. apis was not present as single‐species detections in the salivary glands (see Table 2). Nosema ceranae was more prevalent throughout the 8 months. Significant correlative relationships were established for N. ceranae and N. apis levels in the honeybee glands and those found within the intestines of forager honeybees. Overall, the seasonality of N. ceranae and N. apis in the different glands tightly followed the seasonal patterns in the honeybee guts. Conclusions: Nosema ceranae and N. apis are not tissue specific, and honeybee glands have potential to become a useful indicator of the extent of disease in the colony and may represent a potential infection reservoir. Significance and Impact of the Study: First report of spore load quantification of Nosema spp. in different honeybee glands.     

Serous gland dimorphism in the skin of Melanophryniscus stelzneri (Anura: Bufonidae)

Two serous gland types (I and II) in the skin of the Argentine toad Melanophryniscus stelzneri were discovered using light and electron microscopy. Glands of the two types differ in several traits: features of the products (both mature and immature), organelles involved in biosynthesis, and paths of serous maturation. No consistent differences, however, were detected between the myoepithelial sheaths encircling the secretory units. Type I glands manufacture vesicles containing a single dense body with a repeating substructure and conform to the fundamental secretory line of bufonid skin, a secretory line involved in biosynthesis of steroids. Type II glands synthesize granules of varying densities and seem to belong to a line of glands that secrete proteinaceous products. The occurrence of the two serous gland types in Melanophryniscus stelzneri is discussed in a comparison with current literature on the morphofunctional characteristics of anuran poison glands, which perform both regulative and defensive roles. It is suggested that di- or polymorphism in serous glands is an adaptive trait that allows differential release of active molecules on the body surface. J. Morphol. 237:19–32, 1998. © 1998 Wiley-Liss, Inc.