bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphological changes in the cochlear nuclear complex in primate phylogeny and development
Authors: Heiman‐Patterson Terry D. , Strominger Norman L.
Published: February 2005

The primate cochlear nuclear complex exhibits several characteristic morphological differences in the various primate families from Lorisidae through Hominidae. The most striking differences occur in the organization of the dorsal cochlear nucleus in which the laminar pattern becomes progressively obscured. Granule cells form an external granular layer as well as being intermixed within the molecular and pyramidal layers in slow lorises and squirrel and rhesus monkeys. Whereas a prominent external granular layer remains in chimpanzees, granule cells are scant in other portions of the nucleus. Human adults lack an external granular layer. A small number of granule cells occur but with inconstant distribution. Primates lack the linear array of pyramidal cells oriented perpendicularly to the epithelial surface as seen in cats.

The granule cell layer exhibits similar regression in development of the human cochlear complex. The external granular layer is prominent in the fetus but rapidly decreases in size after birth. It achieves its adult form prior to 18 months. The data suggest that neuronal attrition, or programmed cell death, may be the major mechanism accounting for the alterations that occur in the human granule cell layer.

Other differences in cytoarchitecture, within the great apes and humans, include decreases in the small and giant cell populations of the cochlear complex. These changes, in consort with the organizational changes and reduction of granule cells as noted above, suggest a trend towards reduced intranuclear integration at the level of the cochlear nucleus coupled with encephalization of the auditory system.
Motor innervation and proprioceptors of the mouthparts in the worker honey bee, Apis mellifera. I. Mandibular nerve
Authors: Masuko Keiichi
Published: February 2005

The innervation of the mandibular nerve of the worker honey bee was investigated primarily with methylene blue vital staining. Results on the motor innervation were compared with those of earlier work, yielding some corrections and new findings. The nerve to the mandibular abductor muscle not only carries motor fibers but also supplies sensory branches to the head integument and to the presumptive proprioceptors which probably monitor movements of the proboscis. A small neural mass which is equipped with two systems for proprioception is situated at the point where the mandibular nerve divides into its major branches. One system is composed of receptor muscles stretched between the anterior tentorial arm (AT) and the mandible and multipolar cells. The other is composed of elastic strands between AT and the apodeme of a smaller branch of the mandibular adductor and tripolar cells. The former is stretched by mandibular abduction and the latter by adduction. The two systems collectively are called the mandibular muscle receptor organ. There are two groups of receptor muscles: the outer receptor muscle, which is located outside the neural mass, and the inner receptor muscle located within. Only the latter is innervated by multipolar cells. Another, single, multipolar cell is attached to the surface of the tendon of the inner receptor muscle. A further pair of bipolar‐multiterminal cells attaches to the epidermis at the extremity of the apodeme of the mandibular adductor. One originates from the mandibular nerve and the other from the labral nerve. Both presumably respond to the epidermal expansion caused by mandibular abduction.
Surface specializations of planarian gastrodermal cells as revealed by staining with ruthenium red
Authors: Hori Isao
Published: February 2005

Regional differences of the surface of planarian gastrodermal cells are emphasized by staining with ruthenium red (RR). It is proposed that such differences reflect functional diversity of the luminal, lateral, and basal surfaces of the cells. The luminal surface is coated with a uniform layer of the RR‐positive substance, which penetrates into the intercellular space at the intermediate junction. The septate junction situated just beneath the intermediate junction shows a permeability barrier to the RR tracer. At the basolateral surface, however, RR stains the septate junction in which the electron density of individual septa is enhanced remarkably. The gastrodermal cells are delineated entirely with RR‐positive substance passing freely through the gap junction fuses into the outer leaflets of adjacent plasma membranes. The irregularly dilated intercellular space at nonjunctional appositions includes a slight deposit of RR‐positive substance which attaches to the plasma membrane. The basal surface is underlined by the continuous basal lamina, which consists of the lamina lucida and the lamina densa. The lamina densa has a conspicuous affinity for RR. The lamina lucida is characterized by irregular deposits of RR‐positive substance, some of which concentrates on the hemidesmosomal portions. Treatment with the enzyme hyaluronidase prior to staining with RR abolishes the staining of the basal lamina. As a result, the material of the lamina densa appears flocculent.
Ultrastructure of the body cavity lining in a secondary acoelomate, Microphthalmus cf. Listensis westheide (Polychaeta: Hesionidae)
Authors: Smith Peter R. , Lombardi Julian , Rieger Reinhard M.
Published: February 2005

The organization of the body cavity lining in selected regions of the juvenile and adult of the interstitial hesionid polychaete Microphthalmus cf. listensis is described. Tissues comprising the body cavity lining in the juvenile consist of somatic and splanchnic circular and longitudinal muscles and undifferentiated cells. Somatic and splanchnic cell layers exhibit epithelial ( = eucoelomate) organization in the pharyngeal region. In the midbody, some undifferentiated cells exhibiting mesenchymal organization persist among the epithelially organized somatic and splanchnic cells, forming a gradation between eucoelomate and acoelomate tissue organizations. A coelomic cavity is absent. Tissues comprising the body cavity lining of the adult consist of somatic and splanchnic circular and longitudinal myocytes and coelenchymal cells. Coelenchymal cells are shown from serial section analysis to be mesenchymal in organization and derived from the somatic peritoneum. A 30–65‐nm coelomic cavity lies between the apices of somatic and splanchnic cell layers in the pharyngeal region. In the anterior setigerous segments, the coelom is reduced to a narrow cavity surrounded by coelenchymal cells lying midventrally between the paired ejaculatory ducts. There is a regional obliteration of the splanchnic musculature in the posterior segments so that apices of the coelenchymal cells lie in direct apposition to the basal extracellular matrix of the gut. The coeom is only present middorsally as a 0.7‐μm‐wide cavity. Although the coelomic cavity is highly reduced in the adult, the body cavity lining still reveals its origin from the epithelial ( = eucoelomate) organization. The findings of this study illustrate possible organizational intermediates in the evolution of the acoelomate from the eucoelomate condition in annelids.
The fine structure and development of calcified skeletal elements in the body wall of holothurian echinoderms
Authors: Stricker Stephen A.
Published: February 2005

The calcareous ossicles and iron‐rich calcified granules in the integument of sea cucumbers (Echinodermata: Holothuroida) have been examined by light and electron microscopy. Most ossicles are perforated, platelike structures that measure 100–500 μm long and consist of magnesium‐rich calcite. The formation of ossicles occurs within multinucleated syncytia of sclerocytes that are situated in the dermal layer of the body wall. Sclerocytes possess fairly large numbers of mitochondria and are characteristically enveloped by an external lamina. Each ossicle arises as a minute rodlike spicule that branches and develops into a fenestrated skeletal element. When viewed by SEM, fully developed ossicles appear non‐crystalline. Following decoration with synthetically grown calcite seeds, however, each ossicle reveals an ordered array of crystallites that seem to be aligned perpendicular to the ossicle's original plane of growth. Examinations of sectioned ossicles indicate that the mineral phase in each skeletal element lacks a well developed matrix of EDTA‐insoluble organic substances. Ossicles first arise in the ciliated, lecithotrophic larvae of Eupentacta quinquesimita at about 1 week postfertilization. Two‐week‐old specimens adopt an epibenthic existence and subsequently become enveloped by imbricated ossicles that are secreted by sclerocytes resembling those found in adults. In molpadiid holothurians, the adult body wall contains numerous reddish‐brown granules that are chiefly composed of iron‐rich subunits. The dermal granules differ from calcitic ossicles in developing extracellularly in association with finely filamentous material.
Morphology of the compound eye of the giant deep‐sea isopod Bathynomus giganteus
Authors: Chamberlain Steven C. , Meyer‐Rochow V. Benno , Dossert William P.
Published: February 2005

The structural organization of the compound eye of the largest known isopod, Bathynomus giganteus, is described from four specimens maintained in the laboratory for as long as two months. Living specimens have not previously been available for study. The two triangular compounds eyes measure about 18 mm on the dorsal edge and are separated by an interocular distance of 25 mm. They face forward and slightly downward and may have significant overlap in visual fields. Each eye contains about 3,500 ommatidia in animals of body lengths from 22.5 cm to 37.5 cm. The packing of ommatidia is not uniform across the retina, but is nearly hexagonal in the dorsal central region and nearly square in the ventral and lateral periphery.

The dioptric elements in each ommatidium consist of a laminar cornea, which is flat externally and convex internally, and a bipartite crystalline cone. Sometimes seven and sometimes eight retinular cells closely appose the proximal tip of the cone and bear the microvilli of the rhabdom. Proximal to the rhabdom the retinular cells form thin pillars near the periphery of the ommatidium, and the central portion along the optic axis at this level is occupied by interstitial cells that contain massive arrays of clear vesicles thought to serve as reflective elements. The arhabdomeral segments of the retinular cells and the interstitial cells rest on a basement membrane. Within each ommatidium the basement membrane has two extensions with cylindrical cores and thin sheets of dense material and collagen‐like filaments. These sheets occupy spaces between adjacent interstitial cells up to the level of the rhabdomeral segments of the retinular cells. Arrays of pigment cells with relatively weak light‐screening properties separate adjacent ommatidia.

Animals were fixed both in light within a week of being brought from depth into daylight, and after 2 months of maintenance in constant darkness following such daylight exposure. In both cases, microvilli of the rhabdom were severely disrupted and the retinular cytoplasm contained numerous multivesicular bodies. Exposure to natural daylight appears to cause irreversible structural damage to the photoreceptors of these animals.
Location and analysis of byssal structural proteins of Mytilus edulis
Authors: Benedict Christine V. , Waite J. Herbert
Published: February 2005

The acellular attachment organ (byssus) of the marine mussel Mytilus edulis L. is composed of threads that emanate from the body of the mussel to adhesive discs that anchor the threads to rocks, sand and other mussels. Three proteins have been purified by immunohistological methods and located to specific regions of the byssus. A collagenous protein with subunit molecular weights of 53,000, 55,000 and 65,000 is found in the matrix of the elastic thread region. Its 73,000‐MW precursor was extracted from foot glands in the area proximal to the animal body and was identified by immune cross‐reactivity. A cystine‐rich, acidic protein was found in all regions of the byssus associated with a third protein, the polyphenolic protein. The L‐dopa‐containing polyphenolic protein appears in the cortex of the entire thread and adhesive plaque and at the substrate‐plaque interface. Antiserum to this protein stains spherical vesicles in the phenol gland of the foot. Using immuno‐electrophoretic methods, the polyphenolic protein and the cystine‐rich protein were shown to form high molecular weight aggregates with aging of the byssus.
Changes in femoral morphology during egg‐laying in Alligator mississippiensis
Authors: Wink Carole S. , Elsey Ruth M.
Published: February 2005

Birds and many reptiles are egg‐layers. Birds provide calcium for the formation of eggshells by resorbing medullary bone, which is laid down before ovulation. Turtles do not possess this mechanism and resorb structural bone to form eggshells. Femora from three groups of alligators (egg‐laying females; quiescent, immature, or barren females; and males) were examined to determine if alligators, which are closely related to birds in evolution, resorb structural bone during the formation of eggshells as do turtles. Microradiographs of cross sections from femoral mid‐shafts were analyzed for porosity, and the robusticity index of each femur was determined. Scanning electron micrographs of anorganic endosteal and periosteal femoral surfaces were analyzed to determine numbers of entrances of vascular canals, numbers of lacunae of osteoblasts, and types of femoral surfaces. Femora from egg‐laying females were significantly less robust than those of other females or males, and sections of bone from the egg‐layers were significantly more porous than those of the other groups. Scanning electron microscopy of anorganic femoral endosteal surfaces from egg‐laying females revealed significantly more resorption areas when compared with males or non egg‐laying females. Periosteal surfaces from egg‐layers had significantly more resting and less bone‐forming surface than those from the other groups. Results indicated that apposition of periosteal bone may have been reduced in egg‐layers and that egg‐laying alligators, like turtles, resorb endosteal structural bone, which may be used as a source of calcium for the formation of eggshells.
Ultrastructure of putative migrating cells in the cerebral cortex of Lacerta galloti
Authors: Garcia‐Verdugo J. M. , Farinas I. , Molowny A. , Lopez‐Garcia C.
Published: February 2005

Cells considered to be migratory in the cerebral cortex of adult lizards are ultrastructurally of two types. Nuclei in the first type have highly dispersed chromatin, creating a spongy appearance, whereas in the second type the chromatin is irregularly clumped. Both types of cells are closely associated with processes of radial ependymal glia cells, which perhaps orient their migratory pathways. Cells with spongy chromatin show an increase in cytoplasmic organelles and progressive chromatin condensation as they travel from the ependymal layer to the granular layer. Possibly these cells account for the neuronal increase that takes place in the granular layer during postnatal life. Cells with chromatin clumps are very scarce; ultrastructurally they resemble immature reptilian astroglia cells.
Calcium regulation in the embryonic chick. II. Ultrastructure of the parathyroid glands in shell‐less and in ovo embryos
Authors: Clark Nancy B. , Dunn Bruce E.
Published: February 2005

The ultrastructure of the parathyroid glands was studied in chick embryos developing normally in ovo or in shell‐less culture (after removal of the eggshell). Shell‐less chick embryos are significantly hypocalcemic relative to their in ovo counterparts. At 12 days of incubation, the parathyroid glands of shell‐less embryos contain more lipid and show evidence of increased protein synthetic activity relative to those grown in ovo (more rough endoplasmic reticulum, presence of some dense secretory granules). The glands from in ovo embryos do not contain secretory granules at this age. At 15 days of incubation, the in ovo glands have developed signs of protein synthetic activity similar to those of the 12‐day shell‐less embryos. However, the parathyroids of the 15‐day shell‐less embryos appear strikingly more active than at 12 days, containing stacks of concentric RER membranes and increased numbers of secretory granules. By 18 days of incubation, the ultrastructure of the glands of the two groups is indistinguishable, both appearing to be more active than the 15‐day shell‐less group. Thus, protein synthetic activity of the parathyroid glands, as detected by ultrastructural alterations of the chief cells, normally appears to be initiated during the latter part of embryogenesis (by approximately 15 days incubation) and its onset can be stimulated at least 3 days prematurely by hypocalcemia.
Ultrastructure of spermatogenesis in the hawaiian red lobster, Enoplometopus occidentalis (randall)
Authors: Haley Samuel R.
Published: February 2005

Electron microscopy of spermatogenesis in the Hawaiian red lobster, Enoplometopus occidentalis (Randall), has revealed unusual activity within membranous organelles. Mitochondria‐like bodies (MLB‐1) seen first in spermatogonia appear in primary spermatocytes to swell and fuse as the cytoplasm develops annulate lamellae and other membrane complexes. In early spermatids, annulate lamellae derived from the nuclear envelope contribute to development of an extensive lamellar membrane complex within the cytoplasm, the forerunner of the lamellar region. Other mitochondria‐like bodies (MLB‐2) originate from this membrane complex and contribute to formation of the acrosomal vesicle, which assumes a semicrystalline organization composed of bundles of tubular components slightly larger in diameter than microtubules. An amorphous subacrosomal material may be equivalent to the acrosomal tubule of other decapod spermatozoa. Centrioles at the base of the acrosome produce microtubules that extend between the membranes of the lamellar region distally through the uncondensed nucleus as the cores of the three radial arms of this aflagellate spermatozoon. Nuclear material and electron‐dense lamellar region membranes project into the bases of these radial arms. Nuclear and plasma membranes are fused except where the acrosome lies between them. Of the mitochondria‐like bodies, the MLB‐1 do not persist into spermiogenesis, and the MLB‐2 are derived from the lamellar region. This is in contrast with other reported studies of lobster spermatozoon ultrastructure.
Histological and cytological structure of the gastrointestinal tract of the luderick, Girella tricuspidata (pisces, kyphosidae), in relation to diet
Authors: Anderson Trevor A.
Published: February 2005

The gastrointestinal tract of Girella tricuspidata, an herbivorous teleost, is differentiated into esophagus, stomach, pyloric caeca, intestine, and rectum. The mucosa of the esophagus consists almost entirely of elongated secretory cells, with an underlying submucosa and prominent circular and longitudinal muscle layers. The anterior part of the stomach contains a mucous surface epithelium and a network of tubular glands having only one type of glandular cell, to which secretion of both pepsinogen and HCl is attributed. The tubular glands are not present in the pyloric region. The gastric wall contains well developed circular muscle and submucosal layers. The pyloric caeca contain a mucosa containing two types of exocrine cells. The nature and function of secretions from these cells is discussed. The intestinal mucosa is differentiated into an anterior (ca. 30%) and a posterior section. The enterocytes of the anterior portion show evidence of lipid absorption, while those of the posterior intestine and rectum show considerable pinocytotic activity. The pyloric caeca, intestine, and rectum have a layer of submucosa and a thin layer of circular muscle. The presence of the prominent circular muscle in both the esophagus and the stomach is postulated to be advantageous to an herbivorous fish. However, other ultrastructural features of the gastrointestinal tract of the luderick are similar to those described in carnivorous fish and appear to show no specialization for herbivory.
Structure, function and evolution of the reproductive system in females ofHebrus pusillusandH. ruficeps(hemiptera, gerromorpha, hebridae)
Authors: Heming‐van Battum Karin E. , Heming B. S.
Published: February 2005

Females ofHebrus pusillusandH. ruficepshave two ovaries of five telotrophic ovarioles each, two lateral oviducts, a common an intricate sperm storage and delivery system, the gynatrial complex, and a short, tubular ovipositor. The skeletomusculature of this system is fully described in both species and its functions (summarized in Figs. 55–66) reconstructed from study of living bugs, dissections, whole mounts and serial sections.

To mate, a maleH. pusillusjumps on the back of a female, induces her to lower her ovipositor, and, within 12 min (at 18–24°C), introduces the endosoma of his phallus up its shaft and fills his seminal duct with sperm. The female draws this into her gynatrial sac at the end of copulation and transfers it into her spermatheca in about 30 min (both sperm and spermatheca are longer than the female's body). A single, large egg passes from an ovariole into the vagina where its apex is temporarily lodged in a fertilization chamber. Spermatozoa are drawn from or swim out of the spermatheca into a grooved fecundation canal in the roof of the vagina and forward to the micropyle of the egg. After fertilization, the egg enters the base of the ovipositor and is deposited.

The gynatrial complex of female, semiaquatic bugs probably evolved to accommodate the fertilization of the proportionately larger eggs of a lineage of bugs ancestral to Gerromorpha that was being selected for small body size and was then modified to increase the role of the female in controlling fertilization of eggs.
Structure of the brain and eye heater tissue in marlins, sailfish, and spearfishes
Authors: Block Barbara A.
Published: February 2005

Marlins, sailfish, and spearfishes have a heat‐producing tissue beneath the brain and adjacent to the eyes. This tissue warms the brain and eyes while the rest of the body remains at water temperature. The heater tissue is derived from the superior rectus eye muscle. Only a portion of this eye muscle contains normal skeletal muscle tissue; the rest consists of the modified muscle tissue that is associated with heat production. The heat‐producing portion is supplied with blood through a countercurrent heat exchanger that originates from the carotid artery. The vascular rete prevents the heat being produced by the tissue from being dissipated at the gill. An unusual circulatory supply to the eyes and brain is associated with the presence of the heater tissue in these fishes.
Structural and functional relations of the white sturgeon alimentary canal (Acipenser transmontanus)
Authors: Buddington Randal K. , Doroshov Serge I.
Published: February 2005

The anatomy and histology of the white sturgeon digestive system is described for the adult stage and the first 36 days of posthatch development. Although the adult gut is only 87% of standard length, absorptive surface area is effectively increased by the thick mucosa of the postgastric gut and by lengthening of the gut due to the presence of the spiral valve and the pyloric caecum. Modifications of the gut of this species, relative to that of other chondrosteans, are consistent with its durophagous feeding habits. The arrangement of the intestinal epithelium differs from that of most fish and is organized so that absorptive activities occur in deeper regions, whereas goblet cells dominate the lumenally exposed epithelium. The gut develops from an intraembryonic yolk endoderm. At conclusion of the endogenous nutrition phase the alimentary canal is similar to the adult form and a functional gastric region is present. The anatomical characteristics coincide with physiological data collected throughout the life history of this species.
Transport of sperm within the cloaca of the female red‐spotted newt
Authors: Hardy Matthew P. , Dent James Norman
Published: February 2005

The transport of sperm in the cloaca and adjacent regions of the female red‐spotted newt was examined. It was found that within 1 min after sperm were introduced into the vent, they progressed in a random pattern past the apertures of the spermatheca (the gladular, sperm storage organ that opens from the anterior roof of the cloaca) forward to the anterior end of the cloaca and on into the posterior regions of the hindgut and bladder. Sperm did not enter the dorsal recess of the cloaca into which the oviducts and ureters open. After 1 day, few sperm remained within the cloaca lumen. Sperm were not transported into the cloacae of artifically inseminated, anesthetized females without prior administration of norepinephrine to their cloacal mounds. Treatment of the cloacal mounds of naturally inseminated females with an antagonist of neuromuscular transmission (lidocaine) decreased the numbers of sperm in the anterior cloaca relative to those of saline‐injected control specimens. Neither dead newt sperm nor live rabbit sperm entered the spermatheca. Rabbit sperm, however, entered the oviduct. It is argued that passive and active mechanisms of sperm transport work in concert. Contractions of smooth muscle, which may be initiated during courtship, probably serve to draw sperm passively into the cloaca and up to and beyond the apertures of spermathecal tubules, but sperm, once in the vicinity of those apertures, probably swim actively into them.
Structural and histochemical aspects of perirenal adipose tissue in fetal pigs: Relationships between stromal‐vascular characteristics and fat cell concentration and enzyme activity
Authors: Hausman G. J. , Thomas G. B.
Published: February 2005

Samples of perirenal adipose tissue were obtained from four fetuses from each of seven crossbred gilts at each of three stages of gestation: 70, 90, and 110 days. Samples were routinely prepared for histochemistry and histology. At each age, the largest fat cell clusters were consistently located near points where large blood vessels entered the loose connective tissue. Cell‐cluster size decreased with distance from the entry points of large blood vessels. Fat cells proximal to entry points of large arterioles and fat cells distal to entry points of large arterioles were the same size. Enzyme cytochemistry disclosed that reactions for glucose‐6‐phosphate dehydrogenose (G6PDH), lipoprotein lipase (LPL) and NADH‐TR enzymes were reduced in distal (relative to entry points of large arterioles) adipocytes compared with proximal adipocytes. Reactions for succinate dehydrogenase (SDH) and lactate dehydrogenase (LDH) in adipocytes were not influenced by location within the tissue. Small fat cell clusters with sparse capillary beds surround arterioles in distal areas of sections from fetuses at 70, 90, and 110 days of gestation. In the proximal areas of sections from 110‐day‐old fetuses, arterioles were surrounded by large fat cell clusters with dense capillary beds. These characteristics serve to distinguish perirenal depots from subcutaneous depots in the fetus.
Comparative study of a new ultrastructural specialization of the mammalian retinal pigment epithelium: Basal intracytoplasmic tubules
Authors: Korte Gary E. , Goldberg Gary
Published: February 2005

We recently described basal intracytoplasmic tubules that arise from the basal plasma membrane of rat retinal pigment epithelial cells (RPE). They are a previously undescribed ultrastructural specialization of the basal plasma membrane in addition to the well‐known basal folds. This report describes similar tubules in the RPE cells of the rabbit, hamster, and kitten. As in the rat, the tubules in the hamster and kitten ramify singly through the basal cytoplasm and bear no special relationship to any other organelle. In the rabbit, however, stacks of closely apposed tubules frequently abut the large lipid droplets in their RPE cells. Although the function of the tubules is unknown, their occurrence in several different mammals suggests they are involved in the function of RPE cells in general.
Epididymis of the Indian wall lizard (Hemidactylus flaviviridis) during the sexual cycle and in response to mammalian pituitary gonadotropins and testosterone
Authors: Haider Shamim , Rai Umesh
Published: February 2005

The histology and histochemistry of the epididymis of the Indian wall lizard Hemidactylus flaviviridis (Rüppell) was studied in normal and hormone‐treated males. The ductus epididymidis showed a considerable variation in epithelial cell height and lumenal diameter along its length. It can be divided approximately into anterior, middle, and posterior regions. Epithelial cell height was maximal in the middle region and minimal in the posterior region. The lumen of the ductus epididymidis increased markedly in diameter from anterior to posterior ends with a concomitant increase in the sperm density. During the breeding phase, epithelial cell height and lumenal diameter of both ductuli and ductus epididymidis become markedly enlarged. The epithelium of reproductively active ducts was filled with secretory granules. Both the secretory granules of the epithelium and the secretory material mixed with sperm in the lumen showed a positive reaction to Sudan Black‐B, indicating the presence of lipid. The relative effects of mammalian FSH and LH on the regressed epididymis revealed that only FSH was capable of stimulating the growth and secretory activity of the epididymis.
Intrafusal muscle fibers of duck muscle spindles
Authors: Adal M. N. , Cheng S. B. Chew
Published: February 2005

Serial transverse paraffin sections of intrafusal muscle fibers of spindles from the extensor pollicis and the extensor digitorum communis of ducks show that only one type of intrafusal muscle fiber exists, based on the mid‐equatorial nucleation pattern, diameter, and length. Although the overall range in fiber diameter at the mid‐equatorial region is between 4.2–20.0 μm, the average caliber is 10.4 ± 3.18 μm (S.D.) for spindles of the extensor pollicis and 9.3 ± 2.11 μm (S.D.) for spindles of the extensor digitorum communis muscles. The range in spindle length for the extensor pollicis is 290–2,090 μm, average 1,120 ± 569 μm (S.D.), and for the extensor digitorum communis 1,160–2,500 μm, average 1,745 ± 367 μm (S.D.). Therange in number of fibers per spindle for the extensor pollicis muscle is 5–12, average 8.2, and for the extensor digitorum muscle it is 1–11. In the extensor digitorum communis, there appear to be two groups, based on fiber number. Spindles of one group have a range of 5–11 fibers per spindle with an average of 7.2, whereas the second group has a range of 1–4 with an average of 2.7 fibers per spindle. The second group of spindles constitutes 52.5% of the 40 spindles studied, and of these 7.5% were monofibril spindles, 15.0% difibril, 17.5% trifibril, 12.5% quadrifibril spindles.
Cellular dynamics of conjugation in the ciliate euplotes aediculatus. II. Cellular membranes
Authors: Geyer James J. , Kloetzel John A.
Published: February 2005

The formation and subsequent dissolution of a common bridge of cytoplasm between conjugating ciliated protozoan cells provides an excellent opportunity to follow the dynamics of the cellular membrane systems involved in this process. In particular, separation of conjugant partners offers the chance to observe, at a fixed site on the cell surface, how the ciliate surface complex of plasma and alveolar membranes (collectively termed the “pellicle”) is constructed. Consequently, cortical and cellular membranes of Euplotes aediculatus were studied by light and electron microscopy through the conjugation sequence. A conjugant fusion zone of shared cytoplasm elaborates between the partner cells within their respective oral fields (peristomes) to include microtubules, cytosol, and a concentrated endoplasmic reticulum (heavily stained by osmium impregnation techniques) that may also be continuous with cortical ER of each cell. Cortical membranes displacd by fusion are autolyzed in acid phosphatase‐positive lysosomes in the fusion zone. As conjugants separate, expansion of the plasma membrane may occur through the fusion of vesicles with the plasma membrane, presumably at bare membrane, presumably at bare membrane patches near the fusion zone. The underlying cortical alveolar membranes and their plate‐like contents are reconstructed beneath the plasma membrane, apparently by multiple fusions of dense‐cored alveolar precursor vesicles (APVs). These precursor vesicles themselves appear to condense directly from the smooth ER present in the fusion zone. No Golgi apparatus was visible in the fusion zone cytoplasm, and no step of APV maturation that might involve the Golgi complex was noted.
Structure of hematopoietic nodules in the ridgeback prawn, Sicyonia ingentis: Light and electron microscopic observations
Authors: Martin Gary G. , Hose Jo Ellen , Kim Janet Jieun
Published: February 2005

The architecture and fine structure of the epigastric hematopoietic nodules of the ridgeback prawn, Sicyonia ingentis, are described. The nodules consist of a highly branched series of tubules that contain the maturing hemocytes within a connective tissue stroma. Hemocytes can exit the hematopoietic nodules by penetrating through fenestrations in the endothelial cell layer into the central hemal space or by migrating through the outer later of capsular cells and associated collagen fibrils. Four hemocyte categories were observed: agranular, small granule with cytoplasmic deposits, small granule without cytoplasmic deposits, and large granule hemocytes. This classification was based upon the presence, size, and type of cytoplasmic granules and the presence of cytoplasmic deposits. Only agranular cells and small granule hemocytes without cytoplasmic deposits appeared capable of division. Intermediate stages were observed between agranular hemocytes and small granule hemocytes with deposits and between small granule hemocytes without deposits and large granule hemocytes, suggesting existence of two distinct hemocyte lines.
Collateral projections from trigeminal sensory nuclei to ventrobasal thalamus and cerebellar cortex in rats
Authors: Patrick George W. , Robinson Merryn A.
Published: February 2005

The retrograde fluorescent labeling technique reveals that trigeminal projections to the ventroposteromedial nucleus of the thalamus (VPM) of the rat originate from the main sensory nucleus (MSN) of the trigeminal and subnuclei interpolaris (V1) and caudalis (Vc) of the spinal trigeminal nucleus. These projections are predominately contralateral; however, the presence of a few ipsilateral labeled cells in MSN suggests an uncrossed trigeminothalamic pathway. Trigeminocerebellar fibers projecting to the paramedian lobule (PML) of the cerebellar cortex are located in Vi and caudal subnucleus oralis (V0). This is principally an ipsilateral pathway, but several bisbenzimide‐labeled cells are present in contralateral Vi. The most notable finding occurred after paired injections of Evans Blue into VPM and bisbenzimide into PML, demonstrating neurons in Vi with divergent projections to both structures. The presence of this type of projection was not found in mice (Steindler: J. Comp. Neurol. 237:155–175, 1985) and has not been reported in other species.
Oogenesls in the terrestrial hermit crab, coenobita clypeatus (decapoda, anomura): II. Vitellogenesis
Authors: Komm Barry S. , Hinsch Gertrude W.
Published: February 2005

Oocytes from the land hermit crab, Coenobita clypeatus, in various stages of vitellogenesis were examined by light and electron microscopy. Early vitellogenic oocytes are characterized by accumulations of discrete vesicles of endoplasmic reticulum in the perinuclear cytoplasm. As oocytes develop, the endoplasmic reticulum becomes abundant, and numerous Golgi complexes are seen. There is a well developed Golgi‐endoplasmic reticulum interaction. Within the confines of the reticulum are discrete intracisternal granules, which can be seen coalescing into electron‐dense yolk bodies. Lipid accumulation is seen throughout the cytoplasm. Coincident with the burst of intra‐oocytic metabolism are oolemma modifications and micropinocytosis, which provide ultrastructural evidence for extra‐oocytic yolk production. The mature oocyte contains numerous yolk and lipid vesicles of varying electron density that comprise both intra‐ and extra‐oocytic substrates.
Fine structure and absorption of ferritin in the digestive organs of Loligo vulgaris and L. Forbesi (Cephalopoda, Teuthoidea)
Authors: Boucher‐Rodoni Renata , Boucaud‐Camou Eve
Published: February 2005

The digestive organs possibly involved in food absorption in Loligo vulgaris and L. forbesi are the caecum, the intestine, the digestive gland, and the digestive duct appendages. The histology and the fine structure showed that the ciliated organ, the caecal sac, and the intestine are lined with a ciliated epithelium. The ciliary rootlets are particularly well developed in the ciliated organ, apparently in relation to its function of particle collection. Mucous cells are present in the ciliated organ and the intestine. Histologically, the digestive gland appears rather different from that of other cephalopods. However, the fine structure of individual types of squid digestive cell is actually similar to that of comparable organs in other species, and the squid cells undergo the same stages of activity. Digestive cells have a brush border of microvilli, and numerous vacuoles, which sometimes contain “brown bodies.” However, no “boules” (conspicuous protein inclusions of digestive cells in other species) could be identified in their cytoplasm; instead only secretory granules are present. In the digestive duct appendages, numerous membrane infoldings associated with mitochondria are characteristic features of the epithelial cells in all cephalopods. Two unusual features were observed in Loligo: first, the large size of the lipid inclusions in the digestive gland, in the caecal sac, and in the digestive duct appendages; and second, the large number of conspicuous mitochondria with well‐developed tubular cristae. When injected into the caecal sac, ferritin molecules can reach the digestive gland and the digestive duct appendages via the digestive ducts, and they are taken up by endocytosis in the digestive cells. Thus, it appears that the digestive gland of Loligo can act as an absorptive organ as it does in other cephalopods.
Seasonal changes in a lizard pituitary: Immunocytochemistry and ultrastructural morphometry of lactotropes, corticotropes, and gonadotropes
Authors: Pearson Anita K. , Licht Paul
Published: February 2005

Pituitary glands of adult male lizards (Anolis carolinensis) were studied in an effort to monitor seasonal cytologic changes quantitatively. Cells were identified immunocytochemically and on the basis of ultrastructural characteristics.

Electron micrographs of the anterior pars distalis (containing lactotropes, corticotropes, and gonadotropes) of lizards collected in spring and fall were analyzed morphometrically. Lactotropes are the most numerous cell type in this area and occupy the largest volume. They are closely followed by corticotropes. Neither kind of cell undergoes a marked seasonal change in number or size or in the percent of the analyzed volume they occupy. Morphometric and ultrastructural criteria indicate an increased level of activity in all three kinds of secretory cells in the spring, although changes are relatively modest in corticotropes and lactotropes.

Gonadotropes occupy less than half the volume of either of the other secretory cells in the analyzed area, but undergo considerable seasonal modification. They are larger (> 40%) and more numerous (20%) in the spring, and show an increase in biosynthetic organelles at this time. Although the density of secretion granules may be reduced in the enlarged spring gonadotropes, the number of granules per cell may not be altered seasonally.

Seasonal changes in the three cell types analyzed are moderate in contrast to the cytologic modifications described in pituitary cells following castration or other experimental procedures. Necrotic cells appear to be a normal component of the pituitary gland of Anolis carolinensis throughout the year.
Mesodermal metamerism in the teleost, oryzias latipes (the medaka)
Authors: Martindale Mark Q. , Meier Stephen , Jacobson Antone G.
Published: February 2005

Previous studies of the metameric pattern in mesodermal tissues of chick, mouse, turtle, and amphibian embryos have indicated that segmental characteristics exist along the entire length of the embryo. This paper describes this phenomenon in a fish embryo, for some differences in the cranial segmental plan exist between the anamniote and the amniote embryos hitherto studied. Embryos of the cyprinodont, Oryzias latipes, were fixed at various times, then examined by means of stereo scanning electron microscopy. As in other vertebrate embryos, the first indication of mesodermal metamerism in this fish embryo is the occurrence of somitomeres, which are orderly, tandemly arranged units of uncondensed mesenchymal cells in the paraxial mesoderm. As many as ten somitomeres can be observed caudal to the last formed somite to the elongating tail region. In addition, 7 somitomeres are present rostral to the first definitive somite, which is segment number eight. As in other vertebrate embryos examined, somitomeres in Oryzias embryos are circular, bilaminar arrays of paraxial mesoderm that form before any indications of segmentation can be seen with the light microscope. In the trunk region these mesodermal units condense to give rise to definitive somites, but in the head they eventually disperse. Despite a fundamentally different mode of gastrulation and a relatively small number of cells in the newly formed somitomeres, cranial segmentation in Oryzias embryos was found to be more similar in number to the metameric pattern of the embryos of the bird, reptile, and mammal than to the situation found in the two amphibians studied thus far.
A morphological study of the anterior nervous system of the praesoma of Neoechinorhynchus cylindratus (Acanthocephala: Neoechinorhynchidae)
Authors: Gee Randall J.
Published: February 2005

The nerve pathways in the praesoma, based on light microscopy of serial transverse, sagittal, and longitudinal sections stained with Ehrlich's acid hematoxylin are described for the first time for a memeber of Neoechinorhynchus. The route from the cerebral ganglion to the musculature and sense organs of the proboscis and body wall for 11 nerves, five pair and one single, the presence and structure of the Stutzzelle (support cell) and its association with the neck sense organs are described. A comparison with the nervous system in the praesoma of Paulisentis fractus is discussed.
Seasonal changes in the oviduct of the pied myna (Aves: Sturnidae)
Authors: Gupta S. K. , Maiti B. R.
Published: February 2005

Study of the oviduct of the pied myna (Sturnus contra contra) throughout the year reveals that oviducal weight, length, surface epithelial height and glycogen content are low during August to January (nonbreeding phase), partially increase during February to April (prebreeding phase), maximally increase in May (breeding phase) and decrease in June and July (post‐breeding phase). In the nesting cycle, there is greatest growth in all the regions of the oviduct from early nest‐building to the egg‐laying period and this is followed by rapid involution during incubation and nestling periods.

Some notable features in the oviduct of the pied myna are described: (1) All five regions of the oviduct (infundibulum, magnum, isthmus, uterus, and vagina) are clearly distinguishable when studied from serial sections of the oviduct even during the nonbreeding phase of the annual ovarian cycle. (2) There is a strong correlation between initiation of tubular gland formation and the onset of nestbuilding activity. (3) The distal part of the magnum is differentiated into a ‘mucous region’ having well developed basal nonciliated cells. (4) A sixth zone can be identified between the magnum and isthmus. Sperm hostlike glands exist at the cranial end of the zone. (5) Several circular epithelial invaginations are evident in the intermucosal folds and their size decreases in centripetal order in the vagina. (6) The pattern and degree of regression are different in various regions of the oviduct.

A close synchrony between ovarian and oviducal cycles is indicated in the pied myna (Sturnus contra contra).
Morphology of neurosecretory cells delineated with cobalt applied extracellularly to the cephalic aorta of the insect Rhodnius prolixus
Authors: Chiang R. G. , Davey K. G.
Published: February 2005

Cobalt applied extracellularly to the cephalic aorta in Rhodnius prolixus filled neurosecretory cells (NSCs) located in the brain, the retrocerebral complex, and the suboesophageal ganglion (SOG). Axons of these cells converged over the corpora cardiaca and corpus allatum and merged into a large tract before travelling posteriorly along the ventral side of the aorta. Cobalt‐filled cells in the posterior margins of the brain and the retrocerebral complex lacked extensive dendritic arborizations, suggesting that their cell bodies and/or axonal processes in the retrocerebral complex are directly involved with integrative processes determining hormone release. Cobalt‐filled cell bodies in the anterior region of the brain were closely associated with the ocellar nerve, and the cobalt‐filled cells in the SOG formed extensive dendritic arborizations in the neuropile, suggesting the involvement of sensory cells in regulation of their electrical activity. The ability to fill NSCs with cobalt applied to the aorta demonstrates that the cephalic aorta of R. prolixus is an important neurohaemal region.