bluuebunny/crossref_metadata_2025 huggingface dataset:
A correlative microscopical analysis of differentiating ovarian follicles of mammals
Authors: Anderson Everett , Wilkinson Richard F. , Lee Gloria , Meller Samuel
Published: February 2005

The mammalian ovary has been studied by optical microscopy and by scanning and transmission electron microscopy with the purpose of presenting an integrated view of the differentiating mammalian follicle. During follicular development, changes in the granulosa cells are particularly noteworthy and include dramatic modifications in cell shape coincident with antrum formation. The cytoplasmic processes of those granulosa cells immediately surrounding the oocyte, as well as the more peripheral granulosa cells comprising a second and third layer, traverse the zona pellucida, infrequently interdigitate with the microvilli of the egg, and make both desmosomal and gap junction contacts with the oocyte. The zona pellucida is thus distinguished by numerous fenestrations of varying diameters. The membrana limitans (basal lamina) is a bipartite structure composed of (a) a homogeneous stratum upon which the peripheral layer of granulosa cells rests, and (b) an outer region of collagen‐like fibers. The specific advantages and limitations of the different methodologies utilized to study folliculo‐genesis are discussed.
Comparative studies on the circulatory system of the compound ascidians, Botryllus, Botrylloides and Symplegma
Authors: Mukai Hideo , Sugimoto Keiji , Taneda Yasuho
Published: February 2005

The circulatory systems of four polystyelids, Botryllus schlosseri, B. primigenus, Botrylloides violaceus and Symplegma reptans, were compared. The palleal buds are connected to the parent zooid by a peduncle and to the colonial vascular system by connecting vessels. The peduncle of S. reptans disappears at an earlier stage of bud development than in B. primigenus; it survives the dissolution of the parent zooid in B. schlosseri and B. violaceus. The connecting vessel is formed by anastomosis between an epidermal outgrowth from the bud and a neighboring colonial vessel, and is characterized by the presence of a sphincter. The number of connecting vessels formed in a palleal bud is three in S. reptans, two in B. primigenus and one each in B. schlosseri and B. violaceus. In each species, the larva has eight rudiments of ampullae. In B. primigenus, the original ampullae degenerate soon after metamorphosis and new ampullae extend from the ventral epidermis of the oozooid. In the other species, the colonial vascular system is derived from the original ampullae.

The whole colonial vascular system contracts and expands periodically, with regionally different phases. During each expansion cycle, the sphincter contracts once in B. primigenus and twice in S. reptans. The correlation may be due to blood pressure and the propagation of excitation through the colonial vascular system.
Studies on the annual reproductive cycle of the female cobra, Naja naja. IV. OVARIAN HISTOLOGY
Authors: Lance Valentine , Lofts Brian
Published: February 2005

Morphological changes of the ovary of the Chinese cobra, Naja naja, throughout the annual reproductive cycle are described. A single clutch of between 6 and 22 eggs is produced in late June. From July to the following April the ovary remains quiescent and contains small previtellogenic, hydration stage follicles. The growth of an ovarian follicle from a primary oocyte to maturation and ovulation is estimated to take three years. The histology of the germinal epithelium and the follicular granulosa shows seasonal changes correlated with the growth of the oocyte. During the quiescent period, the germinal epithelium lacks mitotic activity, but during April, when yolk deposition and rapid growth of the preovulatory follicles take place, the germinal epithelium shows intense mitotic activity. The growth of the smallest hydration stage follicles, and the occurrence of cytoplasmic bridges between the pyriform cells of the granulosa and the developing oocyte, also appear to increase during this period. The possible function of the pyriform cell is discussed and the literature on the origin and fate of these cells in the squamate ovary is reviewed. Postovulatory follicles (corpora lutea) and two types of atresia are described and compared with what is known of these structures in other reptiles.
The typology and topography of the tarsal chemoreceptors of the blow fliesCalliphora vicinaRobineau‐Desvoidy andPhormia terranovaeRobineau‐Desvoidy and the HouseflyMusca domesticaL
Authors: Van Wolk Fran M. Der
Published: February 2005

A comparative morphological study concerning typology and topography of chemoreceptors on the prothoracic legs ofCalliphora vicina, Phormia terranovaeandMusca domesticahas been carried out. The typological criteria of Grabowski and Dethier ('54) and Hansen and Heumann ('71) were used. A single criterion, the shape of the tip, was used to define the different types of chemoreceptors.

A‐hairs have a rhombic pore at the side of the tip; B‐hairs have an oval pore at the tip apex and D‐hairs have a rectangular pore under an undulated, cap‐like structure at the hair tip. A‐, B‐and D‐hairs were found in the tarsomeres ofPhormia; inMuscaandCalliphoraonly B‐ and D‐hairs were found. An opening and closing mechanism may operate on the pores of the tips of the chemoreceptors. Chemoreceptors were counted and a topographical map was completed, using SEM‐techniques. Topographical maps are of value in electrophysiological and behavioural research, where only a limited optical magnification is possible.
Fine structure of the macronucleus during the cell division cycle of Euplotes eurystomus, a Ciliate Protozoon
Authors: Ruffolo John J.
Published: February 2005

This paper reports new observations obtained from a study of macronuclear fine structure throughout various stages of the cell division cycle of Euplotes. Study of the ultrastructural organization of the macronuclear chromatin indicates that much of the chromatin is organized into continuous masses, portions of which appear to be attached to the nuclear envelope. The macronuclear envelope appears unchanged in the region of a replication band, and apparent attachments of the chromatin to the inner membrane of the nuclear envelope are maintained in the reticular and diffuse zones. Intranuclear helices were never observed in the diffuse zone. During macronuclear division, linear elements (fibrils or microtubules) were observed in close association with both chromatin bodies and nucleoli. The ultrastructural data suggest that the intranuclear linear fibrils have two functions: elongation of the dividing nucleus, and attachment of chromatin bodies and nucleoli to the envelope. The significance of these observations for macronuclear division and chromatin segregation is considered.
The fate mapping of the eleventh and twelfth day mouse otocyst: An in vitro study of the sites of origin of the embryonic inner ear sensory structures
Authors: Li Cheuk W. , Van De Water Thomas R. , Ruben Robert J.
Published: February 2005

An experiment was undertaken to determine which sensory structures of the mouse embryo inner ear developed from what portion of the mouse otocyst. Otocysts of gestation days 10, 11, 12 and 13 were divided by surgical dissection into six anatomical groups: dorsal, ventral, anterior, posterior, medial and lateral halves. They were organ cultured separately. After a period of ten days, the explanted tissues were harvested and processed histologically for microscopic analysis. The surgical control specimens fixed at the time of explanation were composed of undifferentiated ectodermal cells for tissues of gestation days 10, 11, and 12. Otocysts of gestation day ten showed no gross morphological differentiation. Otocysts of gestation days 11 and 12 showed, during the course of their subsequent growth, that the three semicircular ducts and their associated cristae developed from the dorsal and lateral halves. Only the anterior and posterior canals and cristae originated from the medial portion. The posterior half gave rise to the posterior crista and the anterior half provided for the development of the anterior and lateral cristae. The cochlear duct and its sensory epithelium developed in all the anatomical groups except the dorsal half. The utricle developed in the dorsal section of the middle third of the otocyst, while the utricular macula developed in the anterior half of the same section of the otocyst. The saccule and its macula differentiated from the ventral section of the middle third of the anterior half.
The anatomy of the reproductive system in male Dutch rabbits (Oryctolagus cuniculus) with special emphasis on the accessory sex glands
Authors: Holtz W. , Foote R. H.
Published: February 2005

The morphology and microscopic anatomy of the reproductive organs and colliculus seminalis of the male rabbit are described and illustrated. Special attention is given to the accessory sex glands, because not all have been accurately identified previously. The terminology suggested for the accessory glands (with other terms commonly used in the literature in parentheses) follows: glandula vesicularis (glandula seminalis, vesicula seminalis), proprostata (glandula vesicularis, coagulating gland, prostata), prostata, paraprostata (glandula Cowperi superior), glandula bulbourethralis (glandula Cowperi inferior). The English equivalents are vesicular, proprostate, prostate, paraprostate and bulbourethral glands. Organs were obtained from 39 adult Dutch‐belted rabbits that averaged 2,023 g in bodyweight. Organ weights (means and standard deviations) were as follows: testis, 2.035 ± 0.529 g; caput epididymidis, 0.264 ± 0.087 g; corpus epididymidis, 0.046 ± 0.019 g; cauda epididymidis, 0.398 ± 0.123 g; proximal part of the ductus deferens, 0.098 ± 0.026 g; ampulla of the ductus deferens, 0.177 ± 0.069 g; vesicular gland, 0.529 ± 1.169 g; proprostate gland, 0.633 ± 0.304 g; prostate gland, 0.411 ± 0.181 g; paraprostate gland, 0.040 ± 0.019 g; bulbourethral gland, 0.390 ± 0.133 g; and epididymal fat pad, 0.545 ± 0.339 g. Correlations among organ weights were calculated and interrelationships among them and bodyweight are discussed.
Forebrain projections of the pigeon olfactory bulb
Authors: Rieke Garl Kalman , Wenzel Bernice M.
Published: February 2005

The olfactory system of the pigeon (Columba livia) was examined. Our electrophysiological and experimental neuroanatomical (Fink‐Heimer technique) data showed that axons from the olfactory bulb terminated in both sides of the forebrain. The cortex prepiriformis (olfactory cortex), the hyperstriatum ventrale and the lobus parolfactorius comprised the uncrossed terminal field. The crossed field included the paleostriatum primitivum and the caudal portion of the lobus parolfactorius, areas which were reached through the anterior commissure. In this report the relationships between areas that receive olfactory information and the possible roles that olfaction plays in the birds' behavior are discussed.
Ultrastructural features of the retina and optic nerve of Strombus luhuanus, a marine gastropod
Authors: Gillary Howard L. , Gillary Elsa Winter
Published: February 2005

The retina and optic nerve of Strombus luhuanus were examined by transmission electron microscopy in order to provide an ultrastructural basis for their electrophysiological responses, described elsewhere. The retina exhibits a distinct rhabdomeric layer and layers of cell nuclei and neuropile. These layers are comprised predominantly of three cell types that can be readily distinguished on the basis of their shape, their nuclei and cytoplasmic inclusions such as vesicles and filaments. One type of cell, apparently a photoreceptor that depolarizes in response to photic stimulation, possesses a long distal segment with microvilli; such distal segments comprise the bulk of the rhabdomeric layer. A second cell type, which appears to be supportive in function, contains a bundle of tightly packed tonofilaments that extend across the retina from the capsule to the vitreous body; this cell is quite narrow except in the region near the rhabdomeric layer, where it is expanded and wraps around the other cell types. A third type of cell possesses many short microvilli that project from its apical end into the rhabdomeric layer; it may be a second type of photoreceptor or another type of neuron. The retina also contains bundles of cilia that appear to project from a possible fourth type of cell. The layer of neuropile contains numerous processes that exhibit a variety of vesicle types and structures generally associated with synapses; these appear to play a role in mediating inhibitory and excitatory interactions between the retinal neurons. The optic nerve exhibits two populations of fiber distinguishable on the basis of mean diameter. Fibers in these two populations apparently yield “on” and “off” discharges in response to photic stimulation of the eye.
Effects of germanium on the morphology of silica deposition in a freshwater sponge
Authors: Simpson Tracy L. , Refolo Lawrence M. , Kaby Michele E.
Published: February 2005

The effect of germanium on the secretion of siliceous spicules by the freshwater sponge Spongilla lacustris was investigated by exposing germinating and hatching gemmules to varying concentrations of germanium (Ge) in the presence of silicon (Si). Results were analyzed quantitatively and qualitatively and demonstrate that a [Ge]/[Si] (= molar ratio) of 1.0 completely inhibits silicon deposition. Intermediate ratios (0.5, 0.1, 0.01) which are permissive to spicule appearance result in fewer, shorter, and thinner spicules, in proportionately fewer microscleres, and in short bulbous megascleres. The size of the bulb increases with increasing [Ge]/[Si], while the length of the bulbous megascleres decreases with increasing [Ge]/[Si]. Microscleres do not demonstrate these graded responses suggesting that they are secreted in an all or none manner. Swellings produced in pond water and bulbs produced in germanium appear to decrease in size with time indicating a spreading of the accumulated silica. The effect of germanium on spicule secretion can be partially explained by its ability to uncouple the growth in length of the axial filament from the growth of the surrounding silicalemma. Under these conditions excess silicalemma is produced in which silica accumulates as bulbs in short spicules. Continuous exposure to Ge is necessary to produce this altered morphology. It is conjectured that the bulbs may be retained due to an inhibition of spreading. which in turn may be caused by the incorporation of germanium into the silica.
Sense organs on the antennal flagellum of a stonefly (Plecoptera, insecta)
Authors: Slifer Eleanor H.
Published: February 2005

Tactile hairs, small chemoreceptor pegs, thick‐walled chemoreceptors, thin‐walled chemoreceptors of several types, coeloconic sense organs and campaniform sense organs are present on the flagellum of a stonefly, Allocapnia recta (Claassen).
The hind limb musculature of the brown kiwi, Apteryx australis mantelli
Authors: McGowan Christopher
Published: February 2005

The most complete account of the hind leg muscles of the kiwi was published a century ago by Sir Richard Owen, in his seventy‐fifth year. This extensively‐cited work has several omissions and errors, and while certain of these were corrected by subsequent authors, sufficient uncertainty remains to warrant a reinvestigation. In the present study a detailed description of the hind leg musculature is given, based upon dissections of two frozen specimens. An indication of the possible function of each muscle is given by assessing its size, action, and fiber‐arrangement, together with tentative data on the relative abundance of twitch and tonus fibers.

The correlation between surface features of bones and muscle attachments is investigated with a view to interpreting palaeontological material. Although the limb and pelvic bones are marked by numerous features which suggest muscle attachments, relatively few can be positively identified with specific muscles. Only 23% of the muscle origins and insertions can be identified, and, with three possible exceptions, no indication of relative size is given by the scars. The possibility of being able to reconstruct the musculature of the kiwi from its skeletal anatomy, much less that of its extinct relatives, is remote.
The fine structure of blood follicles in the earthworm genera Amynthas and Lumbricus (Annelida: Oligochaeta)
Authors: Friedman Marc M. , Weiss Leon
Published: February 2005

Blood follicles of the earthworm Amynthas are hemoglobin‐containing, sac‐like dilatations of blood vessels which connect to the general circulation. Grape‐like clusters of follicles are found posterior to the pharynx, among tufts of micronephridia, and single follicles are located among cells of the pharyngeal gland. In Lumbricus, follicles take the form of simple swellings and irregular‐shaped diverticula of nephridial capillaries.

The fundamental structure of the wall of follicles and of vessels in both genera is the same and consists of two layers: an extracellular vascular lamina and an outer (coelomic) covering of smooth muscle‐like myoperithelial cells. Hemocytes may be free and circulating or they may facultatively attach to the vascular lamina as littoral cells, constituting an incomplete endothelium‐like surface. Hemocytes that appear to be in the process of attaching or detaching are rounded, while adherent cells are flattened and elongate. Free and littoral hemocytes actively endocytose packets of circulating extracellular hemoglobin.

Hemocytes within follicles possess radiating cell processes which also endocytose hemoglobin. Although these cells were presumed to secrete hemoglobin, staining with 3,3′‐diaminobenzidine confirms the presence of hemoglobin only within pinosomes and not within protein‐synthesizing or packaging organelles. The presence of hemosiderin‐like bodies suggests that follicular hemocytes catabolize hemoglobin.

Blood follicles apparently provide a means of significantly increasing cell‐surface area for hemoglobin processing, without substantially increasing the volume and pumping load of the circulatory system.
Ultrastructure of an exocrine dermal gland in the gills of the grass shrimp, Palaemonetes pugio: Occurrence of transitory ciliary axonemes associated with the sloughing and reformation of the ductule
Authors: Dtughtie Daniel G. , Rao K. Ranga
Published: February 2005

Exocrine dermal glands, comparable to the class 3 glandular units of insects, are found in the gills of the grass shrimp, Palaemonetes pugio. The dermal glands are composed of three cells: secretory cell, hillock cell and canal cell. Originating as a complex invagination of the apical cytoplasm of the granular secretory cell, a duct ascends through the hillock and canal cells to the cuticular surface. The duct is divisible into four regions: the secretory apparatus in the granular secretory cell, the locular complex, the hillock region within the hillock cell and the canal within the canal cell. A tubular ductule is contained within the latter two regions. As the ductule ascends to the cuticular surface, its constitution gradually changes from one of a fibrous material to one which possesses layers of epicuticle. During the proecdysial period, the ductule is extruded into the ecdysial space and this is followed by the secretion of a new ductule. Temporary ciliary structures, located near the secretory apparatus of the secretory cell, are associated with the extrusion and reformation of the ductule. Characterized only by a basal body and rootlets throughout most of the intermolt cycle, the ciliary organelles give rise to temporary axonemic processes which ascend through the ductule toward the ecdysial space at the onset of proecdysis. Subsequently, the old ductule is sloughed off and a new ductule is reformed around the ciliary axonemes. Following this reformation, the ciliary axonemes degenerate. The function of cytoplasmic processes, derived from the apical cytoplasm of the secretory cell, is also discussed.
Ordered membrane particles in rhabdomeric microvilli of the housefly (Musca domestica L.)
Authors: Chi Che , Carlson Stanley D.
Published: February 2005

Rhabdomeric microvilli of the housefly were freeze‐fractured (FF) and thin sectioned (TS) for ultrastructural examination. Ordered files of closely packed membrane particles (82 Å wide, 250 Å long) were seen (FF) on the microvillar membrane (usually E face). The long axis of each particle was canted about 45° to that of the microvillus. Occasionally particles in this array appeared on the P face. It is hypothesized that ordered particles may represent either a photopigment precursor stock, a second photolabile pigment, or the newly discovered sensitizing, UV‐absorbing, photostable visual pigment. In the underlying membrane leaflet (P face) were found spherical (85 Å diameter) unoriented particles in a concentration of about 6,000/μm2. The size, shape and density of these structures are compatible with those of rhodopsin particles. These particles also covered the basal area of each microvillus. The findings from TS material were difficult to correlate with those from FF replicas. At high magnification the former showed that the plasma membrane of the transected microvillus is composed of spherical, hollow subunits (averaging 43 Å diameter), sometimes fused to form double, 86 Å units. These substructures were closely packed and continuous around the microvillus. This beaded plasma membrane, in rare cases, was doubled around the microvillus. In other instances the plasma membranes were continuous between neighboring microvilli. The physiological implications of these ultrastructural features are discussed.
The extensor assembly in two species of opossum, Philander opossum and Didelphis marsupialis
Authors: Landsmeer J. M. F.
Published: February 2005

In considering primate and hominoid phylogeny, the fundamental position assigned to opossums is explained partially by the characteristic morphology of their hands and feet. One of the main functional features of the human hand is the ability to make a stabilized arch of the finger. Because the extensor assembly plays a key role in establishing an arched finger, the extensor systems of the digits of both the hands and feet were studied in two species of opossum, Philander opossum and Didelphis marsupialis.

In the foot, two extensor tendons join in each toe to form one tendinous plate, which inserts onto the base of the second phalanx. Lumbricals join this plate along the tibial side, and interosseus insertions are found, although a true interosseus wing is lacking. At the proximal interphalangeal level, a terminal tendon takes its origin from this tendinous plate. This terminal tendon is oval in cross‐section and contains elastic structures. Oblique bands arise from this terminal tendon and run proximally along the proximal interphalangeal joint inserting onto the base of the first phalanx. There are elastic structures in the flexor tendon on the dorsal side near its site of insertion.

In the hand, the main extensor tendons are arranged differently and the interossei contribute substantially to the extensor assembly. Otherwise, the extensor assembly of the hands and feet are quite similar. The function of the so‐called paratendinous intravaginal flexors is discussed as are evolutionary aspects of the extensor assembly.
The telotrophic‐meroistic ovary of megaloptera. I. The ontogenetic development
Authors: Büning Jürgen
Published: February 2005

Sialis flavilatera L. (Sialidae, Megaloptera) has telotrophic‐meroistic ovarioles. The germ cells of the tropharium are organized into two distinct tissues, the central syncytium and the germ cell tapetum. The central syncytium consists of nurse cell nuclei embedded in a common cytoplasm which is rich in ribosomes and mitochondria. Cell membranes are totally absent. The germ cell tapetum surrounds the syncytium and consists of a monolayer of cells, each of which is connected with the central syncytium by an intercellular bridge. The oocytes differentiate from basal tapetum cells by previtellogenic growth. Their nutritive cords remain connected to the central syncytium by the intercellular bridge.

Ovariole development starts soon after hatching with the immigration of germ cells into the ovariole‐anlagen and is finished during pupal stages 23 months later. In apical regions of each tropharium, mitoses occur throughout larval life. The descendants enter the prophase of meiosis which lasts until pre‐vitellogenesis; thus, a differential gradient of position and time is established. About 12 months after hatching, the central syncytium arises at the base of the tropharium from a membrane labyrinth in which intercellular bridges are entangled. Evidence is presented that endopolyploidization does not occur during germ cell differentiation.

Finally, the results are compared with those found in Hemiptera and polyphage Coleoptera. The great diversities are interpreted as an indication for a polyphyletic origin of the telotrophic ovary.
The morphogenesis of the thigh of the mouse with special reference to tetrapod muscle homologies
Authors: Jones Cynthia Lance
Published: February 2005

In order to provide an ontogenetic basis for the establishment of tetrapod muscle homologies and for the analysis of complex mammalian muscle states, a descriptive analysis of the morphogenesis of the thigh of Mus musculus has been made. The pattern and sequence of muscle cleavage and the migrations of individual muscle primordia are characterized from the eleventh day of gestation, when cleavage begins, through early neonatal stages. Observations on skeletal differentiation and lumbosacral plexus formation are also included. Thigh muscle morphogenesis is compared to that in the lizard, Lacerta, (Romer, '42) and the chick (Romer, '27) and homologies identified. An ontogenetic basis for the definition of ancestral and derived muscle states is provided in muscles that are morphologically variable in mammals. These include the gluteus minimus, gracilis, adductor brevis and several hamstring muscles. Certain muscles that show variable innervation patterns in adult mammals, i.e., pectineus, quadratus and adductor magnus, typically develop from premuscle regions that separate muscle anlagen innervated by different nerves. Two muscle anlagen appear in the embryonic mouse thigh and then disappear late in prenatal or early postnatal development. Comparisons with other mammals, especially the marsupial, Marmosa, reveal that these muscles are phylogenetic vestiges that degenerate before maturity. A sartorius vestige is identifiable through the thirteenth day of gestation. A tenuissimus anlage is present until shortly after birth and is clearly innervated by a branch of the peroneal nerve.
Scanning electron microscopy and distribution of specialized mechanoreceptors in the texas rat snake, Elaphe obsoleta lindheimeri (Baird and Girard)
Authors: Jackson Morris K. , Sharawy Mohamed
Published: February 2005

Scanning electron microscopy (SEM) of the surface tubercles of a specialized mechanoreceptor found within the head of Elaphe obsoleta lindheimeri indicates that the tubercle consists of a craterlike structure with a peg emerging from its center. After removal of the outer keratinized layers of the epidermis, the SEM discloses a replicate tubercle on the underlying alpha keratin layer. Over 6000 tubercles were found within a single snake. The mechanoreceptors were more densely concentrated on anterior scales, and their number appears to be species specific so that they are more concentrated in snakes with smaller heads than in those with larger ones.
Fine structure and functions of haemerythrocytes and leucocytes of Sipunculus nudus
Authors: Valembois P. , Boiledieu D.
Published: February 2005

The marine sipunculan worm, Sipunculus nudus Linné, possesses a voluminous coelomic cavity filled with a fluid containing different types of free cells. Most of them (more than 90%) are nucleated haemerythrocytes. They arise from free, small haemerythroblastic cells which are described in this report. Different kinds of leucocytes are also found in the coelomic fluid, particularly granulocytes which are phagocytic cells showing some similarities with vertebrate macrophages. These cells seem to arise from small hyalocytes, which are cells having morphological and physiological resemblances with vertebrate lymphocytes. It appears that the older granulocytes are progressively degranulated and give rise to large hyalocytes. Ciliary cells arising from small cells, very similar to small hyalocytes, have also been observed and it is supposed that they give rise to urn cells. Lastly, some of the biological functions of the free coelomic cells of the sipunculan worms are described.
The secretory response in dissociated acini from the rat submandibular gland
Authors: Fleming Norman , Teitelman Mark , Sturgess Jennifer M.
Published: February 2005

Rat submandibular gland was dissociated by enzymatic digestion with collagenase and hyaluronidase, followed by mild mechanical shearing and filtration through a nylon mesh. The dissociated cell populations contained predominantly groups of acinar cells which maintained their acinar arrangement. The morphological and functional viability of the cells was confirmed by electron microscopic examination and a normal secretory response to β‐adrenergic or cholinergic stimulation was observed. Both isoproterenol (IPR) and carbachol caused the fusion of secretory granules into large vacuoles which were also continuous with the lumen, and into which the secretory product was released. Secretion was assessed quantitatively from the incorporation of 14C‐glucosamine into the acinar cells and its subsequent release into the culture medium as labelled glycoprotein. IPR stimulated secretion to 125% of untreated controls in the concentration range 5 × 10−5 to 5 × 10−7 M, and to 110% of controls at 5 × 10−8 M, after 40 min incubation. Carbachol stimulated secretion to 131% of controls at 5 × 10−5 M and to 115% at 5 × 10−6 M but had no effect at 5 × 10−7 or 5 × 10−8 M. The secretory response was blocked by the respective β‐adrenergic and cholinergic antagonists, propranolol and atropine. These findings show that dissociated rat submandibular acinar cells provide a useful in vitro model for the study of mucus synthesis and secretion.
Ultrastructure of the tastebuds of the red‐eared turtle, Chrysemys scripta elegans
Authors: Korte Gary E.
Published: February 2005

The fine structure of the turtle tastebud has been examined by light, transmission, and scanning electron microscopy. It contains five types of cells on the basis of their cytological features, designated types 1,2,3,A, and B. Types 1, 2, and 3 reach the taste pore, whereas types A and B are located basally. The type 2 cell has access to the tongue surface, i.e., the site of gustatory stimuli, and also synapses onto afferent nerves; it probably is a gustatory receptor cell and corresponds to the so‐called “light” cell observed in other vertebrate tastebuds. Some cells may be differentiating. In support of this hypothesis, light microscopic autoradiography shows that postmitotic cells occur in the tastebuds within 24 hours after administration of H3‐thymidine. The tastebuds of the turtle are similar to those of other vertebrates described electron‐microscopically.
Evolution of the feeding mechanism in primitive actionopterygian fishes: A functional anatomical analysis of Polypterus, Lepisosteus, and Amia
Authors: Lauder George V.
Published: February 2005

The comparative functional anatomy of feeding in Polypterus senegalus, Lepisosteus oculatus, and Amia calva, three primitive actinopterygian fishes, was studied by high‐speed cinematography (200 frames per second) synchronized with electromyographic recordings of cranial muscle activity. Several characters of the feeding mechanism have been identified as primitive for actinopterygian fishes: (1) Mandibular depression is mediated by the sternohyoideus muscle via the hyoid apparatus and mandibulohyoid ligament. (2) The obliquus inferioris and sternohyoideus muscles exhibit synchronous activity at the onset of the expansive phase of jaw movement. (3) Activity in the adductor operculi occurs in a double burst pattern—an initial burst at the onset of the expansive phase, followed by a burst after the jaws have closed. (4) A median septum divides the sternohyoideus muscle into right and left halves which are asymmetrically active during chewing and manipulation of prey. (5) Peak hyoid depression occurs only after peak gape has been reached and the hyoid apparatus remains depressed after the jaws have closed. (6) The neurocranium is elevated by the epaxial muscles during the expansive phase. (7) The adductor mandibulae complex is divided into three major sections—an anterior (suborbital) division, a medial division, and a posterolateral division.

In Polypterus, the initial strike lasts from 60 to 125 msec, and no temporal overlap in muscle activity occurs between muscles active at the onset of the expansive phase (sternohyoideus, obliquus superioris, epaxial muscles) and the jaw adductors of the compressive phase. In Lepisosteus, the strike is extremely rapid, often occuring in as little as 20 msec. All cranial muscles become active within 10 msec of each other, and there is extensive overlap in muscle activity periods.

Two biomechanically independent mechanisms mediate mandibular depression in Amia, and this duality in mouth‐opening couplings is a shared feature of the halecostome fishes. Mandibular depression by hyoid retraction, and intermandibular musculature, consisting of an intermandibularis posterior and interhyoideus, are hypothesized to be primitive for the Teleostomi.
An autoradiographic, biochemical, and morphological study of the harderian gland of the mouse
Authors: Watanabe Masahito
Published: February 2005

Biochemical and morphological properties of the Harderian gland of the mouse were examined by combining autoradiographic, biochemical, and electron microscopic techniques. Autoradiographs show that the radioactive carbon from [U‐14C]glucose injected into the abdominal cavity is completely incorporated into the acid‐insoluble substances within 30 minutes. The results of chemical analysis show that the main components of this gland are glyceryl ether diesters and phospholipids. Scanning electron microscopy shows numerous lipid droplets in the secretory cells and alveolar lumina. Myoepithelial cells lie between the secretory cell base and the basement membrane and have a basket‐like distribution of processes as confirmed by hydrochloric acid and collagenase digestions. Myofilaments are demonstrated in the cytoplasm. Two types of secretory cells (A and B) comprise the alveolar epithelium and can be differentiated under the electron microscope. The cytoplasm of both contains numerous vacuoles. The vacuoles are almost empty in A cells, which are a more numerous constituent of the alveolar epithelium than B cells. However, the vacuoles of the B cells contain densely osmiophilic material. In both, cell types show a merocrine mode of secretion. Unmyelinated nerve cell endings occur in the interstices of the connective tissue, and contain clear or cored vesicles.
An ultrastructural study of the leukocytes of the channel catfish, Ictalurus punctatus
Authors: Cannon M. Samuel , Mollenhauer Hilton H. , Eurell Thomas E. , Lewis Donald H. , Cannon Anita M. , Tompkins Christy
Published: February 2005

Ultrastructural studies on blood leukocytes of the channel catfish, Ictalurus punctatus, show the presence of heterophils (neutrophils), small lymphocytes, monocytes, and thrombocytes. Monocytes cannot always be distinguished from large lymphocytes. Cells resembling macrophages or transitional forms between monocytes and macrophages are occasionally seen. Blood eosinophils and basophils are not found. Thrombocytes and small lymphocytes are the most abundant leukocytes, while monocytes are the least frequently encountered leukocyte. Glycogen, present in all leukocytes, is most abundant in heterophils and least abundant in monocytes. Although monocytes are similar to heterophils in size and shape, a greater amount of rough endoplasmic reticulum, free ribosomes, and fewer granules are observed in monocytes. Heterophils possess oval or elongate granules, which often contain a crystalline or striated structure; small tubules which resemble smooth endoplasmic reticulum, and cristae which traverse the long axes of the mitochondria are frequently seen. Small lymphocytes are characterized by the presence of pseudopodia, many free ribosomes, numerous large mitochondria, dictyosomes (Golgi), and long profiles of rough endoplasmic reticulum. The dictyosomes are often associated with a large zone of exclusion. Bundles of microtubules are observed near the elongated ends of thrombocytes. Deep indentations of the plasmalemma, which give the appearance of vacuoles, are also seen in thrombocytes.
Formation of the pits with taste buds at the lingual root in the striped dolphin, Stenella coeruleoalba
Authors: Komatsu Shunro , Yamasaki Fusao
Published: February 2005

The tongue of the striped dolphin, Stenella coeruleoalba, shows a V‐shaped row of pits on its posterior dorsum. Their development is described on the basis of macroscopic and light microscopic observations on fetal, young, and adult stages. Four to eight pits occur, most often five in the adult. Anlagen of the pits first protrude as round epithelial thickenings which later increase in diameter and become thin. The circular primordia then sink, and grooves oriented both circularly and radially develop in the walls of the shallow pits thus formed. Pits and grooves deepen with development so that older pits become lined with conical projections. As pits grow further, they become elongated anterolaterally, retaining slit‐like openings. Each pit in the adult is 2–8 mm long and about 1 mm wide. The pits are not derived from lingual gland ducts but develop independently. Taste buds resembling those of other mammalian tongues can be found in young dolphins but are few in number and limited to the thin epithelium of the pit projections and to that of the side wall of the pits. They first appear in the late prenatal period but degenerate in the adult. A rich nerve supply is observable in the lamina propria below taste buds in the calf. The pits and their projections in the dolphin correspond to the vallate papillae of other mammals, but whether each projection or a whole pit corresponds to a single vallate papilla is undecided.
The auditory region of dermoptera: Morphology and function relative to other living mammals
Authors: Hunt Robert M. , Korth William W.
Published: February 2005

The dermopteran basicranium combines a primitively constructed and oriented auditory bulla formed by ectotympanic, rostral entotympanic, and tubal cartilage with derived features of the middle ear transformer and internal carotid circulation. Living dermopterans possess a primitive eutherian auditory region that has been structurally modified to perceive a lower frequency sound spectrum than probably was utilized by ancestral Mesozoic therians. Perception of the low to midfrequency range is enhanced in Dermoptera by reducing stiffness in the mechanical transformer while maintaining low mass of the component parts. Stiffness has been reduced by (1) development of an epitympanic sinus about four times the volume of the middle ear cavity proper, (2) detachment of the anterior process of the malleus from the ectotympanic, and (3) by delicate suspension of the ear ossicles within the middle ear.

We apply to dermopterans a measure of hearing efficiency derived from recent functional studies of the mammalian middle ear that regards the middle ear mechanism as an impedance matching transformer. Calculation of the impedance transformer ratio for Dermoptera suggests that these mammals are relatively efficient in comparison to other eutherians in their ability to match the impedance of cochlear fluids to that of air at the eardrum. Dermopterans theoretically are capable of using over 90% of incident sound energy striking the eardrum at the resonant or natural frequency. Mechanical impedance of the middle ear transformer exerts a minimal influence on hearing efficiency due to low mass, little stiffness, and little frictional resistance.

Analysis of measurements of the middle ear transformer published by Gerald Fleischer and integration of these data with current theory on the peripheral hearing mechanism in mammals allow us to propose a model that describes the structural and functional evolution of the mammalian middle ear transformer. Structural changes appear to be correlated with alteration in function from primitive small mammals with stiff middle ear transformers and high frequency dominated hearing to mammals with a wider range in body size with more mobile middle ear transformers and a greater range of frequency perception, often including improved sensitivity to lower frequencies.

Mammals employ different anatomical strategies in attainment of increased hearing efficiency and sensitivity. Efficiency is improved by adjustment of lever and areal ratios of the middle ear transformer to achieve an optimum impedance match of external air and cochlear fluids. Sensitivity over a broad frequency spectrum is attained by minimizing mass, stiffness, and frictional resistance of the transformer. The morphology of the auditory region of both living and fossil mammals seems explicable in terms of selection pressure directed toward these ends.
Electron microscopic and autoradiographic studies on vitellogenesis in Necturus maculosus
Authors: Kessel Richard G. , Ganion Larry R.
Published: February 2005

Electron microscope studies on Necturus maculosus oocytes ranging in size from 1.1–1.5 mm in diameter indicate the primary proteinaceous yolk to arise within structures referred to in other amphibian oocytes as yolk precursor sacs or bodies. The origin of these yolk precursor sacs appears to result from the activity of the Golgi complexes which form multivesicular and granular‐vesicular bodies, the limiting membrane of which is at times incomplete. During differentiation, the yolk precursor sacs contain small vesicles similar in size to Golgi vesicles, larger vesicles similar to vesicular elements of the agranular endoplasmic reticulum and, on occasion, a portion of a mitochondrion. The interior of these sacs becomes granular, perhaps by a dissolution of the components just described, and soon becomes organized into a crystalline configuration.

In oocytes 2.0–2.5 mm in diameter, an extensive micropinocytotic activity begins, continues throughout vitellogenesis, and constitutes the primary mechanism for the formation of secondary yolk protein. Numerous coated and smooth‐surfaced vesicles, as well as electron‐dense and electronlucent ones, fuse in the cortical ooplasm to form progressively larger yolk platelets.
Development of the mouthparts in embryos of Haplothrips verbasci (Osborn) (Insecta, Thysanoptera, Phlaeothripidae)
Authors: Heming B. S.
Published: February 2005

The asymmetric “punch and suck” mouthparts of larval Haplothrips verbasci develop from paired appendages in the late, post‐anatrepsis embryo similar to those of other insects. Later, the labrum flexes ventrally over the stomodaeum, the right mandibular appendage degenerates, the maxillary appendages divide into inner (lacinial) and outer (stipital) lobes, and the hypopharynx arises from the venters of the mandibular and maxillary segments. All cephalic segments consolidate anteriorly prior to katatrepsis, their appendages flex ventrally, and the labial appendages fuse medially to form the labium and the primordia of the salivary glands and valve.

The left mandible and the lacinial lobes of the maxillae invaginate into the head during and after katatrepsis to form the mandibular and maxillary stylet‐secreting organs and these later deposit the cuticle of their respective stylets. Cuticle of the mandibular lever is deposited by labral cells at the apex of the mandibular sheath during and after hatching. That of each maxillary lever is secreted simultaneously into the lumen of a ventrally‐directed diverticulum developing from stipital cells at the apex of each maxillary sheath.

Shortly after katatrepsis, the maxillary and labial palpi originate respectively from cells in the outer wall of each stipital lobe and at the apex of the labium.

Muscles of the mouthparts arise after katatrepsis from cephalic mesoderm and are fully‐differentiated before cuticle of the mandibular and maxillary levers has been deposited.

Gnathal morphogenesis in embryos of H. verbasci resembles that occurring in bug embryos and provides additional evidence that Thysanoptera and Hemiptera evolved from a common psocopteroid stem species having small, paired, biting and chewing mandibles and well developed lacinial stylets.
Hopping locomotion in a nematode: Functional anatomy of the caudal gland apparatus of Theristus caudasaliens sp. n.
Authors: Adams Priscilla J. M. , Tyler Seth
Published: February 2005

The interstitial nematode Theristus caudasaliens n. sp. normally locomotes by hopping on the left side of its tail tip, a mode of locomotion that is unique among nematodes. The animal uses its caudal glands and caudal musculature to perform the hops, attaching itself momentarily between hops with the glands and executing the hops by straightening and curling the posterior part of its body.

The caudal gland apparatus can be seen by electron microscopy to consist of five gland cells of two different types. Three of these cells, termed viscid glands, are involved in adhesion of the animal to substrates and produce ovoid granules with a central dense band. The other two cells are characterized by smaller, lessdense granules and presumably function in releasing the animal from substrates. The ducts of both gland types extend to the tail tip where they terminate in a common crescent‐shaped space. Their secretions are released to the outside through two pores on the left side of the tail tip. There is no spinneret valve in this nematode. The muscles of the tail and of the mid‐body region are developed to the same extent.

The caudal gland apparatus can be compared with the duo‐gland adhesive organs of other interstitial animals, but its homology with either these organs or the caudal glands of other nematodes is uncertain. Theristus caudasaliens is described as a new species.