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.     

TRICHOMES OF CANNABIS SATIVA L. (CANNABACEAE)

The diversity of non-glandular and glandular hairs of Cannabis sativa L. (marihuana) are described by scanning electron microscopy. The non-glandular hairs are of two major types, as distinguished by size differences and locations, and all of them are highly silicified. The presence of silica as well as cystoliths of calcium carbonate help in the identification of marihuana even in its ash residues. X-ray microanalyses of Cannabis hairs are compared with those of Humulus lupulus and Lantana camera, whose hairs have been considered to resemble those of marihuana. Glandular hairs are found to be of two major categories. One group consists of glands whose heads are generally made up of eight cells and the other group whose heads are generally made up of two cells but never more than four cells. All glands of both categories are stalked. Some glands of the first category are massively stalked and these are restricted solely to anthers and bracts of staminate and pistillate plants. The massive stalk is considered to be made up of epidermal and hypodermal cells that have grown in response to some stimulation during anthesis. Fine details of the shoot system of Cannabis, such as cuticular ridges on epidermal cells, warty protuberances on non-glandular hairs, and surface views of glands in developing stages are also reported. Glandular hairs on the bracts of Humulus lupulus resemble those of Cannabis.     

Absence of sebaceous glands from the oral mucosa of non-human primates

Whereas sebaceous glands unassociated with hairs are a common and easily seen feature of the mucosa of the cheek and red margin of the lip in man, no glands of this type were found in this situation in autopsy specimens from 47 macaques and single specimens of 5 other species.     

External micromorphology of the frons plate and its adjacent areas in workers of the oriental hornet

The micromorphology of the frons and the adjacent regions in young workers (1–24 hr of age) of the Oriental hornet Vespa orientalis and some adult worker hornets is described. The young workers still lack globular secretions at the bases of the setae. Such secretions do occur at the bases of the setae in the adult workers and are composed mainly of the elements Si, Al, S, Mg, Ca, Cl, and Fe. Contiguous with each of the ocelli is a gland that also secretes minerals. Young workers usually have a relatively large concentration of Ca in the glands behind the paired ocelli. The gland associated with the median anterior ocellus opens by an elongated sutura coronalis in the frons and contains various elements, predominantly Si, but also Ca. The setae (hairs) on the frons are arranged in concentric circles around each of the ocelli; they are long in the upper part of the frons but shorten gradually toward the tip of the frons. The tip lacks hair, but the cuticle bears elevated scales that project as cuticular protuberences. It appears that the ocelli and their associated glands, and the entire frons plate with its hairs and glands at the bases of the hairs in this region, comprise an equilibrium “organ” that senses changes in gravity. © 1992 Wiley-Liss, Inc.     

Epidermal hair morphology in Solatium L. section Solatium

Scanning electron microscopy was used to examine stem, leaf, staminal and stylar hairs on species belonging to Solanum L. section Solanum. The surface morphology of these hairs is illustrated. Simple, uniseriate hairs characterize the section Solanum , and these may have eglandular or glandular heads; they are usually multicellular, but in some species the stylar hairs appear to be unicellular. In addition, stalked glands, described here as spherical, four-celled glands, are universally present in species belonging to the section Solanum.     

Comparative analysis of ultrastructure of glandular trichomes in two Nepeta cataria chemotypes (N. cataria and N. catena var. citriodora)

Glandular trichomes from the leaf surface of Nepeta cataria and N. cataria vai.citriodora have been examined using transmission and scanning electron microscopy. Peltate glands and capitate hairs type I were found on leaves of N. cataria. Both types had single stalk cells. Leaves of N. cataria var. citriodora bore peltate glands with unicellular or bicellular stalk, capitate hairs type I (with unicellular stalk) and capitate hairs type II (with unicellular or bicellular stalk). Peltate glands of N. cataria and of N. cataria var. citriodora were characterized by numerous leucoplasts sheathed by smooth reticular tubules and smooth endoplasmic reticulum; they are proposed to synthesize terpenes. The secretory cells of capitate hairs type I of N. cataria and those of N. cataria var. citriodora had well developed rough endoplasmic reticulum and dictyosomes. They had plastids with protein inclusions. These glands are supposed to produce slime. Capitate hairs type II of N. cataria var. citriodora had no analogs in N. cataria. Their secretory cells exhibited abundance of tubular endoplasmic reticulum and had unsheathed plastids with starch grains. Probably, these glands synthesize terpenes. The results of the study indicate that there is an obvious difference both in morphology and in ultrastructure of glandular trichomes in different chemotypes of N. cataria.     

Secretion-grooming in the water bug Plea minutissima: a chemical defence against microorganisms interfering with the hydrofuge properties of the respiratory region

Abstract. 1. The water bug Plea minutissima Leach (Hemiptera: Pleidae) from time to time crawls out of the water and distributes secretion from its metathoracic glands over the ventral part of its body. By this 'secretion-grooming' antiseptic gland substances, mostly hydrogen peroxide, are applied to the hydrofuge hairs which hold the respiratory air bubble.
2. When the bugs are prevented from leaving the water, their mortality increases significantly, and individuals lacking the air bubble are observed. Examination of such bugs with Scanning Electron Microscopy techniques reveals bacteria growing on their hydrofuge hairs, whereas in bugs allowed to secretion-groom the hairs are not contaminated by microorganisms.
3. Artificial application of diluted metathoracic gland secretion on the body surface of P. minutissima kills bacteria, while specific ciliates, which never colonize the respiratory region, are not harmed by the secretion.
4. It can be concluded that secretion-grooming prevents the contamination of the hydrofuge respiratory region that leads to the wetting of the hydrofuge respiratory regions, resulting in the loss of the air bubble, and, finally, the drowning of the animals.
5. Other possible functions of the secretion, such as chemical defence against predators or wetting of the body surface, could not be demonstrated or seem unlikely.     

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.     

Epidermal hair morphology in Solanum L. section Solanum

Scanning electron microscopy was used to examine stem, leaf, staminal and stylar hairs on species belonging to Solanum L. section Solanum. The surface morphology of these hairs is illustrated. Simple, uniseriate hairs characterize the section Solanum, and these may have eglandular or glandular heads; they are usually multicellular, but in some species the stylar hairs appear to be unicellular. In addition, stalked glands, described here as spherical, four-celled glands, are universally present in species belonging to the section Solanum.     

The skin of primates. XXXI. The skin of the black-collared tamarin (Tamarinus nigricollis)

The black-collared tamarin represents the first detailed study of a member of the family Callithricidae. Although certain features are unique, some of its characteristics resemble those of Prosimii and those of Anthropoidea. The epidermis is moderately pigmented, and the dermis contains numerous elestic fibers. Scattered melanocytes are found throughout both layers. Hair follicles grow in groups of 3 to 4 over the general body surface, including the muzzle. One apocrine gland is associated with each hair group. In the periinguinal region is a large concentration of gigantic sebaceous glands. Apocrine glands occur over the entire hairy skin. Aggregations of these glands on the ventral wrist (in conjunction with sinus hairs) and chest represent the ulnar gland and suprasternal gland, respectively. Apocrine secretory coils of the ulnar gland and external genitalia are surrounded by melanotic, dendritic melanocytes. Eccrine sweat glands are confined to the volar surfaces of the pes and manus. Cholinesterase-reactive granules are dispersed throughout the cytoplasm of the myoepithelial cells.     

Localization and histology of the female sex pheromone-producing gland in the parasitic wasp, Apanteles glomeratus

During the pupal development of Apanteles glomeratus, melanization proceeds stepwise from the eyes to the head, then thorax, dorsal side of abdomen, ventral side of abdomen, and finally to the antennae. Female sex pheromone is already being secreted at the ‘black-eye stage’ during pharate adult development. In the adult stage, the whole body of the wasp shows pheromonal activity. Closer analysis shows, however, that the pheromone-producing glands are located at the base of the 2nd valvifer, and there are approximately a score of pores with hairs on the cuticle in this region. Most of the gland consists of large secretory cells, and a narrow zone of nonsecretory cells separates the main part from the cuticle. Contamination with the pheromone secreted by the glands can account for the pheromone activity of the whole body.     

The pollen-collecting hairs of Campanula (Campanulaceae). I. Morphological variation and the retractive mechanism

The pollen-collecting hairs (PCHs) of Campanula have been a subject of intense debate for the past two centuries. Although several morphological studies have been made on these hairs, detailed comparative studies among species are still lacking, their function and adaptive significance being an unsolved question. The present study comprises two microscopy techniques: scanning electron microscopy and confocal scanning laser microscopy. The aim of the present study is to elucidate: 1) the variation in morphology of the PCHs, 2) the variation in presence/absence of the PCHs by the time of spreading of the stigmatic lobes, 3) the variation in the retractive mechanism of the PCHs, and 4) the correlation between pollination and the retraction of the PCHs. In several species PCHs of various lengths are found. Despite the variations in length of the hairs, the same retractive mechanism is found in all species studied. In most species the hairs retract into basal cavities within the style late in anthesis. The cells into which the hairs retract differ in length among species. Pollen grains are often found within the cavities together with the retracted hairs, a mechanism considered to prevent self-pollination. Pollen germination within the cavities was not observed. In a few species, the PCHs are still present at stigma receptivity. Differences in the shape and size of the cells surrounding the PCHs are documented. The diameter of the pits and the pollen grains vary among species. Other types of hairs on the style are recognized in some species, being of various lengths. These other types do not retract at stigma development and should not be regarded as pollen-collectors. They possibly facilitate for visiting insects to reach the nectar glands, present at the top of the ovary.     

Sensilla on the antennal flagellum of the sawyer beetles Monochamus notatus (Drury) and Monochamus scutellatus (Say) (Coleoptera: Cerambycidae)

The antennae of the sawyer beetles Monochamus notatus and M. scutellatus were examined with the light and scanning electron microscopes to determine the types, number, distribution and innervation of the sense organs. Nine types of sensilla are described. Both short, thin-walled pegs (sensilla basiconica) and reversely curved thick-walled hairs (sensilla trichodea) are chemoreceptors. There are three types of long, thick-walled hairs (sensilla chaetica) which may be mechanoreceptors. One of these is modified in males to form unique snail-shaped pegs. A few dome-shaped organs, probably campaniform sensilla, were found. In addition to sense organs, many glands occur in association with the sensilla, and the antennae are well supplied with dermal glands connected by canals to small pores on the surface.     

Ultrastructural and gas-chromatographic analysis of the preputial glands of male nude (nu/nu) mice

Summary The preputial glands of male nude (nu/nu) mice were analyzed by a combination of electron microscopy and gas chromatography to determine whether or not they are affected, like developing hairs and nails, by the nu/nu genotype. Results of the analyses revealed no differences between the glands of nude and normal male mice in either their ultrastructural characteristics or lipid secretory products.     

The function of the frizzled pathway in the Drosophila wing is dependent on inturned and fuzzy

The Drosophila epidermis is characterized by a dramatic planar or tissue polarity. The frizzled pathway has been shown to be a key regulator of planar polarity for hairs on the wing, ommatidia in the eye, and sensory bristles on the notum. We have investigated the genetic relationships between putative frizzled pathway downstream genes inturned, fuzzy, and multiple wing hairs (inturned-like genes) and upstream genes such as frizzled, prickle, and starry night (frizzled-like genes). Previous data showed that the inturned-like genes were epistatic to the frizzled-like genes when the entire wing was mutant. We extended those experiments and examined the behavior of frizzled clones in mutant wings. We found the domineering nonautonomy of frizzled clones was not altered when the clone cells were simultaneously mutant for inturned, multiple wing hairs, or dishevelled but it was blocked when the entire wing was mutant for inturned, fuzzy, multiple wing hairs, or dishevelled. Thus, for the domineering nonautonomy phenotype of frizzled, inturned and multiple wing hairs are needed in the responding cells but not in the clone itself. Expressing a number of frizzled pathway genes in a gradient across part of the wing repolarizes wing cells in that region. We found inturned, fuzzy, and multiple wing hairs were required for a gradient of frizzled, starry night, prickle, or spiny-legs expression to repolarize wing cells. These data argue that inturned, fuzzy, and multiple wing hairs are downstream components of the frizzled pathway. To further probe the relationship between the frizzled-like and inturned-like genes we determined the consequences of altering the activity of frizzled-like genes in wings that carried weak alleles of inturned or fuzzy. Interestingly, both increasing and decreasing the activity of frizzled and other upstream genes enhanced the phenotypes of hypomorphic inturned and fuzzy mutants. We also examined the relationship between the frizzled-like and inturned-like genes in other regions of the fly. For some body regions and cell types (e.g., abdomen) the inturned-like genes were epistatic to the frizzled-like genes, but in other body regions (e.g., eye) that was not the case. Thus, the genetic control of tissue polarity is body region specific.     

The failure behavior of the anchorage of hairs during slow extraction

Treatment of excessive hair growth is an important issue in both dermatological and cosmetic practice. In contrast to treatments with medication, most physical methods are treatments that focus on the hair follicle. To obtain insight in the failure behavior of the anchorage of hairs, hairs were extracted (in vitro) from pig skin at a speed of 0.1mm/s, one at a time. The pulling force and tweezers displacement were recorded. The extracted hairs were classified with respect to the phase in the growing cycle: anagen (growing phase), telogen (resting phase) or other (catagen phase or unable to determine). The anagen hairs showed a different relation between the tweezers displacement and the pulling force than the telogen hairs. Moreover, the maximum force that could be applied before a hair was extracted proved to be lower for anagen hairs than for telogen hairs (0.36N, 1.8N, respectively). The extracted hair length, defined as the part of the hair that had been embedded in the skin which was extracted, was higher for anagen hairs than for telogen hairs (4.8mm, 3.0mm, respectively). Removing proximal skin tissue and the embedded parts of the anagen hair (root) resulted in a change of the extraction curves. The results indicate that two phenomena play a role in the anchorage of anagen hairs. We have proposed a model for the extraction of an anagen hair that has been based on these results: first the interface between hair and skin that is located around the inner root sheath (IRS) starts to fail, followed by failing of the hair itself in the region where the hair keratinizes.     

Endoplasmic microtubules configure the subapical cytoplasm and are required for fast growth of Medicago truncatula root hairs

To investigate the configuration and function of microtubules (MTs) in tip-growing Medicago truncatula root hairs, we used immunocytochemistry or in vivo decoration by a GFP linked to a MT-binding domain. The two approaches gave similar results and allowed the study of MTs during hair development. Cortical MTs (CMTs) are present in all developmental stages. During the transition from bulge to a tip-growing root hair, endoplasmic MTs (EMTs) appear at the tip of the young hair and remain there until growth arrest. EMTs are a specific feature of tip-growing hairs, forming a three-dimensional array throughout the subapical cytoplasmic dense region. During growth arrest, EMTs, together with the subapical cytoplasmic dense region, progressively disappear, whereas CMTs extend further toward the tip. In full-grown root hairs, CMTs, the only remaining population of MTs, converge at the tip and their density decreases over time. Upon treatment of growing hairs with 1 microM oryzalin, EMTs disappear, but CMTs remain present. The subapical cytoplasmic dense region becomes very short, the distance nucleus tip increases, growth slows down, and the nucleus still follows the advancing tip, though at a much larger distance. Taxol has no effect on the cytoarchitecture of growing hairs; the subapical cytoplasmic dense region remains intact, the nucleus keeps its distance from the tip, but growth rate drops to the same extent as in hairs treated with 1 microM oryzalin. The role of EMTs in growing root hairs is discussed.     

A comparative study of the integument of the camel, Dorcas gazelle and jerboa in relation to desert life

Comparative histological studies of the integuments of the Dorcas gazelle, jerboa and camel have revealed the presence of tubular sweat glands in the skin of the Dorcas gazelle and the camel but not in the jerboa.
Hairs occur in groups in the skin of jerboa and camel but occur singly in the Dorcas gazelle where they are of two types; short under hairs and long covering hairs. Each hair follicle is associated with a sebaceous gland. Both the unkeratinized epidermis and its horny layer are comparatively thin in the jerboa and gazelle, and in dry air this may permit greater loss of water by transpiration than in the camel which has a comparatively thick epidermis.     

Structure of the plantar sweat glands of the Bank vole Clethrionomys glareolus

The plantar pads of the hind feet of 15 male and female, young and old Clethrionomys glareolus (Rodentia–family Muridae) were examined for the presence of tubular glands. Groups of eight or nine coiled glands were found in all of the 11 plantar pads. The secretory portion of the gland lies deep in the fatty hypodermis and communicates with the plantar surface by a coiled duct whose lining cells merge with those of the stratum basale of the undersurface of the foot. Groups of shallow depressions mark the site of the duct openings. They are not associated with any hairs.
Although light microscopy shows only one cell type, electron microscopy reveals two morphologically different cell types. Neither conform directly to the light and dark secretory cells of the human sweat glands although similarities exist. Myoepithelial cells surround the secretory cells, but do not appear to be present around the duct cells.     

Vasculature of the parotoid glands of four species of toads (bufonidae: bufo)

The parotoid glands of toads (Bufonidae) consist of large aggregations of granular glands located between the otic region of the skull and the scapular region. To determine the circulatory pattern of these glands, we perfused the vascular systems of Bufo alvarius, B. marinus, B. terrestris, and B. valliceps with either India ink or Microfil, a fine latex. The perfused glands were studied by gross dissection, microscopic examination, and histology. The vascular patterns of the parotoid glands were compared to the arrangement of vessels in the dorsal skin of Rana sphenocephala (Ranidae), a frog that lacks parotoid glands. The parotoid glands of the four species of toads are supplied with blood by the lateral and dorsal cutaneous arteries and are drained by one or more branches of the internal jugular vein. The dorsal cutaneous artery supplies most of the blood to the parotoid glands in B. terrestris and B. valliceps. In B. alvarius and B. marinus, both the lateral and dorsal cutaneous arteries serve major roles in the blood supply of the glands. These patterns of blood flow have not been described previously for parotoid glands and conflict with earlier accounts for B. alvarius and B. marinus. The arteries and veins associated with the parotoid glands of toads are present in R. sphenocephala, but are arranged differently. In R. sphenocephala, the lateral cutaneous artery supplies the dorsal and lateral skin posterior to the shoulder region, whereas the dorsal cutaneous artery supplies the skin of the shoulder region. In toads, both the lateral and dorsal cutaneous arteries supply the skin of the shoulder region and ramify into subcutaneous capillaries that surround the secretory units of the parotoid glands. Extensive vasculature presumably is important for delivering cholesterol and other precursor molecules to the parotoid glands, where those compounds are converted into toxins.