General Body Surface Research Articles

Ribeiroia marini: Surface ultrastructure of redia, cercaria, and adult

Rediae, cercariae, and adults of Ribeiroia marini were examined using a scanning electron microscope to determine the types of tegumental sensory structures and their locations. Sensory structures were observed among numerous tegumental folds in the area immediately surrounding the mouth of the rediae. These sensory structures are similar in appearance, location and fine structure to sensory structures described from the anterior tips of rediae known to be predacious on the sporocysts of Schistosoma mansoni. These uniciliated structures may function as chemoreceptors to aid the redia in migration through snail tissue. Five types of sensory structures bearing one, two, or multiple cilia were distinguishable on the cercariae. These structures were located on and around the oral sucker, dorsal and ventral body surfaces and on the tail. They may be used by the cercariae to locate the intermediate host fish and to find suitable sites within the lateral line scales for encystment. The ventral surface of the adult fluke is covered with spines and shows an absence of sensory structures on the general body surface. Sensory structures were seen in the area surrounding the oral and ventral suckers. The extended cirrus organ has a folded tegument, but lacks spines or sensory structures.

Scrotal thermoregulation of the bull (Bos sp.)

A comparison was made of evaporative heat loss from the skin of the scrotum and the thorax of the bull. The sweat glands of the scrotum were not controlled independently of those on the general body surface. Scrotal sweat glands were found to be under adrenergic neural control like those of the general body surface. The large sweat glands of the scrotum produced approximately five times as much sweat per gland as those on the general body surface. Localized heating of the scrotum for 20 min stimulated both panting and sweating without any change in deep body temperature. Insensible moisture loss from the scrotum was greater than that from the skin of the general body surface. It is concluded that there are no fundamental differences in the properties of the sweat glands of the scrotum and those of the general body surface, and that the high insensible moisture loss of the scrotum assists with cooling of the skin of the scrotum. It is suggested that a function of the tunica dartos muscle is to reduce insensible moisture loss.

Comparative study of the cranial morphology of the labrids Choeroden venustus and Labroides dimidiatus and the scarid Scarus fasciatus (Pisces : Perciformes) I. Head skeleton

The cranial osteology of C. venustus, L. dimidiatus and S. fasciatus is described. C. venustus and L. dimidiatus possess three features characteristic of the family Labridae: protrusible upper jaws, the ascending process of the maxilla longer than the alveolar process, and the alveolar process of the premaxilla attached by fibrous tissue to the distal end of the maxilla which in turn is fastened to the ascending process of the dentary. The neurocranium of C. venustus shows several features involved in strengthening the skull to withstand the strong forces applied during feeding when crushing molluscs, barnacles and crabs as well as turning over slabs of coral. The forward movement of jaws and eyes have permitted L. dimidiatus to feed by picking small organisms off the general body surface, pharynx, gills and buccal cavity of host fish. S.fasciatus has at least three features characteristic of scarids: fused teeth on the premaxillae and dentary, a premaxilla firmly attached to the maxilla, and a secondary joint between the dentary and articular producing a compound lever type of articulation for the lower jaw. Several modifications help strengthen the upper and lower jaws and enable S. fasciatus to feed by scraping pieces of algae and coral fragments from the surfaces of coral rocks.

Uptake, binding and clearance of divalent cadmium in Glycera dibranchiata (Annelida: Polychaeta)

The bloodworm Glycera dibranchiata Ehlers, 1968 accumulates cadmium through the general body surface and the intestine. Absorption through the gut accounts for cadmium which rapidly binds to coelomic proteins. Intracoelomic injection of 109Cd demonstrates that cadmium binds readily to hemoglobin and other proteins. The degree of cadmium binding is pH-dependent. The apparent pK of binding sites in body wall and musculature homogenates is 5.39. Cadmium ions injected into the coelom at 7 μg g-1 tissue increase proline incorporation rates into the positively charged hemoglobin (cathode fraction) by 15-fold in 3 days. A 3-fold increase of proline incorporation was observed in the anode hemoglobin fraction over the same time period. Radioactivity in various protein fractions decreases at different rates after injection of 109Cd. Comparisons between the function of mammalian metallothionein and the coelomic fluid proteins of G. dibranchiata as a detoxification mechanism are discussed.

The surface topography of a monogenean,Diclidophora merlangi revealed by scanning electron microscopy

The body surface of adult Diclidophora merlangi is characterized by an annular array of irregularly-shaped ridges, with the intervening troughs of tegument invested with microvilli. The microvilli measure approximately 0.5 micrometer in length and 0.06 micrometer in diameter and at maximum density (10.8/micrometer 2) increase the body surface area by a factor of two. On the anterio-dorsal surface of each peduncle the ridge-like structures consolidate as a distinct area of ornamentaltion some 100 micrometer in diameter. A frontal pit opens just inside the mouth and is thought to provide the outlet for the buccal gland secretions. The tegument surrounding the gonopore and paired excretory pores is unmodified in morphology. Presumed sensory endings are of at least two types: (1) uniciliated structures, projecting from a pit or supported by a collar of tegument, and distributed either singly over the general body surface and in the buccal cavity, or in groups around the mouth; and (2) large numbers of non-ciliated papillae localized on the opisthaptor. A number of these papillae occur on a wart-like outgrowth of tegument positioned on the ventral surface of each peduncle and have obvious significance in contact communications.

NEUROENDOCRINE CONTROL OF SWEAT GLANDS

Eccrine glands perform two functions: those on the foot pads of animals and the palms of humans facilitate prehension and are controlled by both adrenergic and cholinergic nerves; those on the general body surface regulate body heat and are controlled by cholinergic nerves. The adrenergic effect in the glands of the palms and soles is mediated through α-receptors. The function of these glands is also modified by humoral agents. Circulating catecholamines increase sweating by stimulating the β-receptors, a matter of physiologic significance because sweating facilitates dissipation of heat induced by exercise. Circulating catecholamines do not seem to cause the sweating observed in pheochromocytoma, insulin hypoglycemia, and hypotension, all of which arc associated with elevated levels of plasma catecholamines. Aldosterone acts on the epithelium lining the excretory duct and stimulates the absorption of sodium, in partial exhange for potassium, from the fluid secreted by the cells of the secretory coil. This absorption produces a hypotonic secretion. In some species, e.g., horses and cows, apocrine glands perform a thermoregulatory function. In all animals so far studied, an adrenergic nerve supply to apocrine sweat glands has been demonstrated; in some species, however, nerve terminals have not been detected histologically. A neurohumoral type of sudomotor transmission has been proposed in which the transmitter is released into the circulatory system in close proximity to the sweat glands. In equine species, circulating catecholamines have been shown to supplement neural stimulation during exercise.

BLACK DEATH, A DISEASE SYENDROME OF PENAEID SHRIMP RELATED TO A DIETARY DEFICIENCY OF ASCORBIC ACID

ABSTRACTCalifornia brown shrimp (Penaeus californiensis) fed a diet low in or without added L‐ascorbic acid, developed blackened lesions (after 6 to 8 weeks in the subcuticular tissues of the general body surface, in the walls of the esophagus, stomach and hindgut, and in the gills and gill cavity. The condition has been previously observed in tank and raceway‐reared P. californiensis and P. aztecus, often in epizootic proportions, and has been named black death disease.The disease has only been observed in postlarval and juvenile shrimp fed alginate‐bound artificial diets in tanks or raceways that received no sunlight and contained no plant material. Handling and other stress factors often precipitated epizootics in apparently healthy groups of shrimp. Once clinical signs of the disease became apparent, affected shrimp ceased feeding, and death usually followed within 24 to 72 hours. Opportunistic bacteria such as Vibrio spp. and Pseudomonas spp. often, But. not always, produced a terminal septicemia in affected shrimp. Mortalities of 1 to 5% per day due to this disease were observed on several occasions in tank and raceway‐reared P. californiensis in 1974 and 1975 at Puerto Peǹasco, Mexico.Histopathology showed the blackened lesions to be, composed of masses of hemocytes and necrotic tissue. The black pigmentation of the lesions was due to melanin deposited in areas of heavy hemocyte infiltration, particularly near the centers of developing hemocyte nodules. No parasites or bacteria could be demonstrated in the centers of these nodules.

Sweating--physiology and pathophysiology.

Summary Sweating is a function of the sweat glands which are present in the skin and widely distributed over the general body surface. Sweat is produced as a thermoregulatory response to heat, either from a rise in environmental temperature or endogenously from a rise in body temperature, e.g. during exercise. Evaporation of sweat from the skin causes cooling as long as the environmental humidity is not excessive. Thermoregulatory sweating occurs over the general body surface, while that which is associated with emotional states is seen mainly on the face, palms and feet. However, considerable differences in the sweating pattern, in response to various stimuli, are found between individuals. Sweating is abnormal when either too much (hyperhidrosis) or too little, or none (hypohidrosis or anhidrosis) is produced either generally or in particular regions of the body. Methods for measuring sweat production and the application of these techniques to studying the pathophysiology of the response are also discussed.

The skin of the giraffe.

The skin of the giraffe has the same general histological structure as that of other mammals, but there are notable features. The skin is heavily pigmented with the epidermis, pilary canals, and the outer cell layer of the apocrine duct richly melanized. Furthermore, melanotic dendritic cells are frequently found in the sebaceous glands, the entire length of the external root sheath, and the secretory tubules of the apocrine glands. The thick skin has a papillary dermis that extends to just beneath the secretory coils of the apocrine glands and bulbs of hair follicles and an equally thick reticular layer below these structures. The hair follicles do not grow in clusters, and with some regional variations, have associated sebaceous glands, apocrine glands, and arrectores pilorum muscles. Only the large hairs have a prominent medulla. In such specialized regions as the eyelids, nose, and lips, the apocrine glands are surrounded by cholinesterase-reactive nerves but the glands on the general body surface are not. The only specialized nerve receptors are hair follicle end organs found on every hair of the eyelids, nose, and lips, but only rarely elsewhere.

Sweating responses during changes of hypothalamic temperature in the rhesus monkey.

A technique is presented for preparing a durable thermode implant in the hypothalamus of the rhesus monkey. In unanesthetized monkeys implanted with thermodes in the anterior hypothalamic area of the brain, a linear relation was found between local sweat rates on the general body surface and clamped hypothalamic temperature. Changes in skin temperature were found to shift the hypothalamic set-point temperature at which sweating began but did not alter the gain of the hypothalamic temperature-sweat rate relationship. This study provides direct support for the concept that central brain temperature and skin temperature interact additively in the control of sweating in higher primates. Due to the very close similarity between these responses and those seen with indirect measurements of brain temperature in men, the rhesus monkey is seen as an excellent experimental analogue for studying human thermoregulation.

Sodium and Chloride Regulation in Uca Adapted to 175% Sea Water

Various aspects of the regulation of Na⁺ and Cl⁻ were studied in fiddler crabs adapted to 175% sea water. Turnover rate for both ions averaged 28% h⁻¹. Total fluxes were partitioned into renal route, intestinal route, and the remainder which was presumed to occur across the general body surface. With urine produced at a rate of 0.5% body weight day⁻¹, renal losses contributed 0.1% total flux for Na⁺ and 0.3% for Cl⁻. Intestinal route provided approximately 5% total influx of both ions assuming complete absorption of all ingested salts. The transepithelial potential (TEP) was - 1.3 ± 0.6 mV. In the absence of Na⁺ the TEP was -8.9 ± 1.3 mV; in the absence of Cl⁻ it was +11.7 ± 0.6 mV. Deletion of Na⁺ or Cl⁻ from the bathing medium reduced efltux of the corresponding ion, an effect associated with exchange diffusion. But other results indicate such effects could also be due to permeability changes in the absence of Na⁺ or Cl⁻. Whether or not exchange diffusion occurs flux ratio analysis indicated both Na⁺ and Cl⁻ were actively pumped from crabs in 175% sea water. Hypotonicity is discussed in relation to estuarine environment the crabs inhabit.

Pre-cuticulin fibril and ecdysial membrane secretion in cyclorrhapha (Diptera)

The nature, function, and occurrence of pre-cuticulin fibrils are discussed. They are shown for the general body surface and more specifically for the pulvillus, where the first-formed fibrils are consolidated into the membrane shown in interference micrographs. Similar fibrils are present in developing tracheae and tracheoles, and the folded developing air sac is embedded in a mass of such fibrils. Of perhaps the greatest interest is the occurrence of similar pre-cuticulin fibrils in imaginal discs throughout larval and pre-pupal life. Thus the cells secreting the fibrils behave as typical epidermal cells, except that they do not embark on the subsequent phases of cuticle secretion until the pupal cuticle is formed, when cuticulin is the first secretory product. The membrane formed of pre-cuticulin fibrils is considered to be quite different from the membrane within the puparium which is typical of the ecdysial membrane of other specific insects, being an inner layer of endocuticle, qualitatively and quantitatively different from the layer of endocuticle secreted earlier.

Schistosoma mansoni: tail loss in relation to permeability changes during cercaria-schistosomulum transformation.

The hind-body region of Schistosoma mansoni cercariae observed in the scanning electron microscope demonstrates various stages of contraction which may be compared with those of living larvae which are secreting the acetabular gland contents. No evidence for an extensive lesion was found in cercarial bodies which had shed their tails under experimental conditions. Experiments on the permeability of the larvae to sodium fluoride, methylene blue and amino acids demonstrated that tail loss significantly affects the permeability of the bodies although the effect is greater immediately after decaudation than at later times. Subsequent increases in permeability may be correlated with a change in the general body surface.

Changes in the darkness of four body features of bluegill sunfish ( Lepomis macrochirus Rafinesque) during aggressive encounters

The darkness of four body features (general body surface, GBS; lateral stripe pattern, LSP; opercular flap spot, OFS; and dorsal fin-ray spot, DFRS) was observed during the formation of 16 pairwise status relationships among bluegill sunfish (Lepomis macrochirus Rafinesque). In eight cases (Method A) an intruder fish was placed into a 110 liter aquarium occupied for 7 previous days by a resident fish. In eight additional cases (Method B) two fish lived on opposite sides of a 110 liter aquarium divided by an opaque screen for 7 days prior to removal of the screen. Dominance was established by one of the fish in all but two cases (both were Method B) and aggressive encounters proceeded through five clearly identifiable stages: (1) a stage of inactivity just after pair formation, (2) a stage in which the fish oriented and approached each other tentatively and without further interaction, (3) a stage in which threat displays are emitted, often by both fish, but no actual body contact occurs, (4) a stage of vigorous attacks, and (5) a stage where one fish is clearly emitting all attacks and where the other fish is fleeing and/or hiding. Darkness of each feature in each fish was evaluated with a statistically reliable three-point scale at each stage during the contest. GBS increased in darkness equally for dominant and submissive fish. LSP, OFS and DFRS became darker in dominant fish and lighter in submissives, suggesting that these three features may have status-related signal value. Method of pair formation did not interact with these effects.

Oxygen uptake and the role of hemoglobin in the East African swampworm Alma emini

1. The rate of oxygen uptake by the lung formed in air above stagnant water by the oligochaetous annelid Alma emini is 50–60% of that by the general body surface in air or water. 2. The blood contains a high molecular weight hemoglobin which transports 32–52% of the oxygen taken up under various conditions. 3. The hemoglobin has a high oxygen affinity (P 50 = 2·6–3·1 in the pH range 6·6–7·4 at 20°C) with a low slope ( n = 0·97–1·44) and a small Bohr shift (Δ log P 50/Δ pH = −0·1).

Magnesium regulation in mosquito larvae (Aedes compestris) living in waters of high MgSO4 content.

ABSTRACT Although larvae of A. campestris can live in natural waters in which the magnesium content may vary seasonally from extremes of 1 to more than 100 mm, the haemolymph levels of magnesium vary only from 1·5 to 4 mm. Larvae survive in water containing 90 mm-Mg and drink their own body weight every few hours, the ingested fluid and the magnesium ions being largely absorbed into the haemolymph via the midgut. The urinary concentration of Mg2+ ions was always substantially higher than that of the external media and up to 23 times that of the haemolymph. It is suggested that magnesium is not excreted across the general body surface, the Malpighian tubules and hindgut being largely responsible for removing magnesium from the haemolymph. These physiological observations are discussed in relation to the environmental conditions under which larvae are naturally found.

Site and mechanism of water vapour uptake from the atmosphere in ixodid ticks.

UPTAKE of water vapour from subsaturated atmospheres has been demonstrated in a variety of terrestrial insects and mites but no previous effort to identify the site and mechanism has been completely conclusive. The tracheal system, the rectum and the general body surface have variously been proposed in specific studies.

Water Uptake from Subsaturated Atmospheres: its Site in Insects

ALTHOUGH the uptake of water from subsaturated atmospheres by some arthropods is well established, neither its mechanism nor its site has been conclusively established. Uptake may occur over the general body surface and the mechanism involve both cuticle and epidermis: much of the evidence is summarized by Beament1–3. Conclusive location of the site of uptake would be an important step in the elucidation of the mechanism. I deal here with a test of the assumption that uptake takes place over the general body surface, attempting to locate the site of uptake more precisely.

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

AbstractThe 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.

Some quantitative aspects of ion regulation in teleosts

1. 1. Data are presented which indicate that little or no significant transfer of water or ions occurs across the general body surface of teleosts. 2. 2. The contribution of chloride cells to regulation of sodium is limited and/or totally unnecessary in some teleosts in fresh water. 3. 3. Data relating to permeability changes of gills of euryhaline fishes transferred from sea water to fresh water are discussed.