bluuebunny/crossref_metadata_2025_split huggingface dataset:
The fine structure of the Limulus optic nerve
Authors: Nunnemacher Rudolph F. , Davis Patricia P. 
Published: February 2005

AbstractTwo complete composite photographs of the optic nerve of Limulus, made by electron microscopy, reveal the presence of neurosecretory granules in the large axons of the rudimentary eye neurons. The number of intermediate sized, (3–7 μ), of eccentric cells corresponds with the number of ommatidia as expected, but only their sheath of Schwann cells show an intimate interfolding. Based on the number of fine axons within the nerve each ommatidium has an average of 12–13 retinular cells. The diameter of their fibers is between 0.2 and 3 μ although the majority are between 1 and 1.5 μ. They are aggregated into bundles of six to seven fibers by the sheath cells although some bundles contain only two, others as many as 181 fibers. There is no indication in these studies that retinular cell axons within a bundle are associated with the same, adjacent, or other pattern of ommatidia. The photographs suggest that physiological activity in retinular cell axons might be detected most easily in the smallest bundles because they contain the fewest, but the larger retinular cell axons.
Adaptive problems and possibilities in the temporal fenestration of tetrapod skulls
Authors: Frazzetta T. H. 
Published: February 2005

AbstractAdaptive explanations for the temporal fenestration in reptiles are briefly reviewed. With few possible exceptions, fenestrate appeared first in the reptiles, and have seemingly evolved independently in several different phyletic lines.The several explanations for fenestration offered by previous authors include speculations that open spaces in the skull permitted bulging of the jaw‐closing muscles, and that fenestrae formed in areas of reduced stress where the presence of bone would be functionally useless. The first of these does not readily apply to initial evolutionary stages; the second is more satisfactory.Certain features of muscular attachments to bones are dealt with, and their implications applied to the fenestration problem to add another possible explanation (which need not contradict previously published suggestions).Considerations of cranial strength in tetrapod skulls led to speculations on the lack of fenestration in temnospondyls, anthracosaurs, microsaurs and cotylosaurs.Emargination of the skull roof in turtles is also discussed.
Sense organs on the antennal flagellum of a giant cockroach, Gromphadorhina portentosa, and a comparison with those of several other species (Dictyoptera, Blattaria)
Authors: Slifer Eleanor H. 
Published: February 2005

AbstractTwo kinds of tactile hairs, plain and wavy, thick‐walled chemoreceptors and two types of thin‐walled chemoreceptors are present on the antennal flagellum of Gromphadorhina portentosa males. These are described and their location on the antenna noted. Females of this species have plain tactile hairs and the same types of chemoreceptors as do the males but wavy tactile hairs are absent. The antennal sense organs of a few specimens of five other species of cockroaches — Periplaneta americana, Blatta orientalis, Supella longipalpa, Pycnoscelus surinamensis and Diploptera punctata — were also examined. All lacked tactile hairs but were provided with thick‐walled chemoreceptors and with two types of thin‐walled chemoreceptors similar to those described for Gromphadorhina portentosa.
Morphology of the larval and adult brains of the monarch butterfly, Danaus plexippus plexippus, L.
Authors: Nordlander Ruth H. , Edwards John S. 
Published: February 2005

AbstractCell population and neuropile morphology of larval and adult brains of the monarch butterfly, Danaus plexippus plexippus, L., are compared. The larval brain is in continuous transition, the processes of adult brain development being underway from the earliest larval stages. It is characterized by a less diverse population of cells and more homogenous fiber areas than those of the adult. Neuroblasts, which divide to form the neurones of the adult brain, occur either in discrete proliferation centers or scattered among the larval ganglion cells. The larval brain contains, in addition to small homogeneous antennal centers and a distinct larval optic center, rapidly developing adult optic centers, corpora pedunculata, and protocerebral bridge. The larval brain lacks a central body. Major differences between larval and adult brains are clearly related to the increased dependence of the adult upon sensory input from the eyes and antennae.
Development of the oocyte and its accessory cells of the polychaete, Diopatra cuprea (Bosc)
Authors: Anderson Everett , Huebner Erwin 
Published: February 2005

AbstractThe oocyte‐nurse cell complex of the polychaetous annelid, Diopatra cuprea, has been explored by various methods of light microscopy and by the technique of electron microscopy. Early in its development the complex appears as a string of cells floating within the coelomic cavity. As this string of cells develops, the volume of one cell (approximately the middle one) increases greatly; while that of the remaining cells, referred to as nurse cells, increase slightly. Due to this differential growth, the two opposing strands of nurse cells are displaced to one side of the oocyte.Nurse cells are joined to one another by cytoplasmic bridges. Cytoplasmic bridges also exist between the strands of nurse cells and the oocyte. The presence of numerous ribosomes within the bridges between the oocyte and nurse cells encourages us to suggest that this organelle may be transferred to the oocyte via this route. The transported ribosomes may be used by the maturing oocyte, or they may be stored by the egg to be utilized during embryogenesis. Moreover, we believe that the nurse cells are not involved in the production of the protein‐carbohydrate yolk bodies for we think that these are elaborated by the endoplasmic reticulum in collaboration with certain Golgi complexes of the oocyte.
Limb regeneration and survival of prolactin treated hypophysectomized adult newts
Authors: Connelly Thomas G. , Tassava Roy A. , Thornton Charles S. 
Published: February 2005

AbstractHypophysectomized adult newts exhibited 98% survival and limb regeneration at 23 days post‐hypophysectomy when injected intraperitoneally every other day with prolactin (0.015 U/newt) and kept continuously in aquaria with 1 × 10−7 concentration of thyroxine. Thyroxine alone was no more effective than saline injections.Prolactin (1.2 U/newt every other day) alone increased survival and limb regeneration, but less effectively than did the prolactin‐thyroxine combination.
Tooth attachment by means of a periodontium in the trigger‐fish (Balistidae)
Authors: Soule John D. 
Published: February 2005

AbstractTooth attachment in the majority of the bony fish is by ankylosis or fibrous membrane. However, in one group of the osteichthys, the trigger‐fish or balistids, tooth attachment is by means of a periodontium composed of a shallow alveolar socket, a periodontal ligament and acellular cementum.Histologically, the balistid periodontal ligament is composed of a dense fibro‐cellular connective tissue possessing an abundance of typical fibrocytes, collagen fiber bundles, and oxytalan fibers. The collagen fiber bundles which resemble the principal fiber bundles of the mammalian periodontal ligament are inserted into the bone of the shallow alveolar sockets and are anchored to the teeth by means of a layer of amorphous acellular cementum that covers the radicular dentin. No cementoblasts were found in functional teeth, and epithelial rests are lacking. The mid‐central zone of the balistid periodontal ligament is occupied by small blood vessels.
Innervation of the antennal musculature of the centipede Scolopendra morsitans Linn.
Authors: Changulani Veena 
Published: February 2005

AbstractA detailed description of the innervation of the individual muscles of the antenna of the centipede Scolopendra morsitans is given. There are six nerves supplying the antennal muscles of each side. The nerve N I consists of 26 bundles of which two are motor, 12 sensory and 12 are mixed. It innervates the intrinsic muscles of the antenna and the antennal sense organs. The nerves N II, N III and N IV innervate the dorsal extrinsic muscles and the nerve N V and N VI the ventral extrinsic muscles.
On the mechanism of respiration in the bullfrog, Rana catesbeiana: A reassessment
Authors: De Jongh H. J. , Gans Carl 
Published: February 2005

AbstractThe mechanism of respiration in the bullfrog has been analyzed by means of pressure recordings from the buccal cavity, the lungs and the abdominal cavity, by cinematography and cinefluorography, and by electromyography of buccal, laryngeal and abdominal muscles. Gas flow was investigated by putting frogs in atmospheres of changing argon and nitrogen content and monitoring the concentration of the nostril efflux.Three kinds of cyclical phenomena were found. (1) Oscillatory cycles consist of rhythmical raising and lowering of the floor of the mouth, with open nares. They have a definite respiratory function in introducing fresh air into the buccal cavity. (2) Ventilatory cycles involve opening and closing of the glottis and nares and renewal of a portion of the pulmonary gas. More muscles are involved and the pattern of muscular activity is more complex than in the oscillatory cycles. (3) Inflation cycles consist of a series of ventilation cycles, interrupted by an apneic pause. The intensity of the ventilatory cycles increases before this pause and decreases immediately thereafter. This results in a stepwise increase in pulmonary pressure, to a plateau (coincident with the pause) followed by a sudden or stepwise decrease.The respiratory mechanism depends on the activity of a buccal force pump, which determines pulmonary pressure whose level is always slightly less than the peak pressure values of the ventilation cycles. The elevated pulmonary pressure is responsible for the expulsion of pulmonary gas during the second phase of the next ventilation cycle. This pressure is maintained by the elastic fibers (and the smooth masculature) of the lungs.
Morphogenesis of body segments and appendages during the larval stages of a common spiroboloid milliped
Authors: Berns Michael W. 
Published: February 2005

AbstractThree‐dimensional, histological, and x‐ray techniques provide a picture of body segment and limb morphogenesis. Cell multiplication begins in the proliferation region (“meristem”) during the molt from the preceding instar. By four days post‐molt, the cells that will form the new segments are well under way in their anterior, lateral, and dorsal migration. It is suggested that after the anlagen for all the new segments are estabilshed, a mitotic wave commences in the most anterior anlagen and moves posteriorly during the remainder of the instar. When cell proliferation is complete, final differentiation of the segments takes place.The process of limb formation is one of cell proliferation and perhaps migration. Each limb develops in a membranous pocket during the instar following the one in which its respective body segment was formed.
Ultrastructure of human labial salivary glands. I. Acinar secretory cells
Authors: Tandler Bernard , Denning Carolyn R. , Mandel Irwin D. , Kutscher Austin H. 
Published: February 2005

AbstractThe structure of human labial salivary gland acini was studied by light and electron microscopy. Contrary to previous reports, these glands were pure mucous in nature; no serous elements were present. The acinar cells were found in all stages of maturation. Immature cells were characterized by an extensive and highly organized rough‐surfaced endoplasmic reticulum. The Golgi complex was extremely prominent, consisting of stacks of flattened cisternae and swarms of small vesicles. Mucous droplets were almost completely absent. As secretory activity progressed, the endoplasmic reticulum involuted, while the Golgi cisternae became distended and formed many vacuoles. In mature mucous cells, the apical cytoplasm was filled with membrane‐bounded mucous droplets, and the nucleus was displaced basally. The droplets frequently showed great variation in density from cell to cell, and even within the same cell they sometimes were quite heterogeneous. They were liberated from the acinar cells by an apocrine process, so that droplets with intact limiting membranes were often observed in the acinar lumen. These droplets soon lysed, their contents fusing into streams of mucus. Occasionally during apocrine secretion a mucous cell failed to reconstitute its apical surface, and its entire contents spilled into the acinar lumen.Unusual cytoplasmic inclusions were present in many of the acinar cells. These inclusions, which were surrounded by a single membrane, consisted of lipid droplets closely associated with bundles of fine filaments.
Ultrastructure of bovine parotid glands
Authors: Shackleford John M. , Wilborn Walter H. 
Published: February 2005

AbstractBovine parotid glands exhibit outstanding structural differences when compared with those of non‐ruminant mammals. The acini are tortuous, branched and lined with cells of different heights, imparting a scalloped appearance to acinar lumina. Numerous microvilli, ca. 1.5 μ in length, extend into the lumina and intercellular canaliculi. Intercellular canaliculi measure ca. 3 μ in diameter and interweave in close association with intercellular tissue spaces. Intercellular tissue spaces are separated from the extraacinar spaces across a basal lamina only, whereas junctional complexes guard canaliculi from direct continuity with tissue spaces and/or extraacinar spaces. Flattened cytoplasmic lamellae extend from adjacent acinar cells and loosely interdigitate with one another across the tissue spaces. Acinar cells contain more mitochondria and less granular endoplasmic reticulum than parotid glands of non‐ruminant mammals. Two types of secretory material, in the form of inclusions which vary in size and electron density, are present in the acinar cells. Intercalated ducts connect acini with striated ducts which in turn, empty into collecting ducts located between gland lobules. In terms of frequency of “basal infoldings” and numbers of mitochondria, striated ducts of calf parotid glands are not as well developed as those of certain other salivary glands. Myoepithelial cells are most often present at junctions of acini and intercalated ducts where they may attach to both acinar and ductal epithelium. Nerve “terminals” were not observed on the epithelial side of basement membranes in relation to the secretory cells.
Special cutaneous receptor organs of fish: III. The ampullary organs of Eigenmannia
Authors: Szamier R. Bruce , Wachtel Allen W. 
Published: February 2005

AbstractAmpullary receptor organs of the South American weakly electric gymnotid fish Eigenmannia virescens consist of a pore at the surface of the skin, a canal through the epidermis, and the expanded basal end of the canal in the corium. The cavity of the organ contains a jelly that is filled with fine fibers. The canal wall consists of three to six layers of flattened cells that appear to be derived from the adjacent skin. Along the lumen of the organ the cells are joined by tight junctions. Usually there are four spherical receptor cells in the base of the organ. They are innervated by single neural terminals. These organs are compared to tuberous receptor organs found in the same species, and the functional significance of the fine structure observed in these cells is discussed.
Special cutaneous receptor organs of fish: IV. Ampullary organs of the nonelectric catfish, Kryptopterus
Authors: Wachtel Allen W. , Szamier R. Bruce 
Published: February 2005

AbstractAmpullary organs of the transparent catfish, Kryptopterus bicirrhus, are present in large numbers on the head and in a regular pattern of lines on the body and fins. The organs lie in the epidermis, and have a pore that opens to the surface. Flattened cells form a roof and walls. On the floor of the organ there are a “sensory hillock,” composed of spherical receptor cells and columnar supporting cells, and a “secretory hillock” composed of columnar secretory cells. The receptor cells are nonciliated and have only afferent innervation. The organ cavity is filled with jelly. The organs are compared with ampullary organs of the weakly electric fish Eigenmannia, ampullae of Lorenzini of Raja, and small pit organs of Amiurus. Structural characteristics of the ampullary organs of Kryptopterus make them especially suitable for electrophysiological studies.
Electron microscopy of the normal and I131 treated thyroid gland of the newt, Notophthalmus viridescens
Authors: Hearing Vincent J. , Eppig Jr. John J. 
Published: February 2005

AbstractThe fine structure of the thyroid of the newt, Notophthalmus viridescens, was studied with the electron microscope. Specimens were injected I.P. with 30 μc of I131 and sample thryoids were examined at 12 hour intervals thereafter. The ultrastructure of the normal thyroid gland is described, and compared with that of the irradiated glands. The first visible ultrastructural change observed after injection of the radioiodin was a striking alteration of nuclear morphology. This effect was followed by an increase in the frequency of whorled lamellar structures, a decrease in the number of microvilli, and degeneration of the Golgi apparatus and endoplasmic reticulum. Further effects observed included an increase in the number of large cytoplasmic granules and a decrease in the number of smaller ones, the presence of autophagic vacuoles, and finally, an increase in the number of degenerated mitochondria.
Analysis of the embryonic sources and mechanisms of development of posterior levels of chick neural tubes
Authors: Criley Bruce B. 
Published: February 2005

AbstractThe mechanisms of development of posterior levels of neural tubes of chick embryos were analyzed by study of serial cross‐sections of a continuous series of normal embryos between 40 to 72 hours of incubation. Two extirpation experiments were performed in ovo on other embryos of the same stages. Descriptive studies revealed the presence of an overlap zone in which two types of neural tube formation occurred. Open neural tube formation (by fusion of neural folds) occurred dorsally in this region; closed neural tube formation (by canalization of solid medullary cord tissue) occurred ventrally. Extirpation of the posterior end of the neural plate produced defects within the lumbosacral region, indicating that the posterior neural plate participates in the formation of the lumbosacrum, and that the overlap zone is therefore in the lumbosacral region. Extirpation of the prospective neural tissue in the anterior end of the tail bud indicated that only the most posterior levels of the neural tube originate exclusively by cavitation of the tail bud. In both extirpation experiments a neural tube formed independently within the tail bud tissue, indicating that formation of the neural tube in this region is not dependent upon direct continuity with neural tissue anteriorly.
An autoradiographic analysis of yolk deposition in the cortex of the cecropia moth oocyte
Authors: Melius Melvin E. , Telfer William H. 
Published: February 2005

AbstractThe cecropia moth oocyte accumulates proteins from the blood during vitellogenesis; the proteins reach the oocyte by an intercellular route, are taken in by pinocytosis, and become components of the protein yolk spheres. Different proteins vary greatly in the extent to which they are incorporated into the yolk spheres. One objective of the work described in this paper was to determine where the selectivity of protein uptake occurs. An autoradiographic analysis of the uptake of tritiated blood proteins injected into the hemocoel indicated that there are at least two sites of selectivity – one between the hemocoel and the intercellular spaces of the follicular epithelium that surrounds each oocyte, and another between the intercellular spaces and the yolk spheres. Another objective was to determine if only proteins from the blood are deposited in the protein yolk spheres. Studies of the incorporation of tritiated leucine provided evidence that the ovary itself synthesizes proteins that are deposited in the yolk spheres along with the blood proteins. Finally, evidence is presented that the various regions of the oocyte cortex are not equally active in the deposition of yolk.
Oocyte‐follicle cell differentiation in two species of Amphineurans (Mollusca), Mopalia mucosa and Chaetopleura apiculata
Authors: Anderson Everett 
Published: February 2005

AbstractDifferentiating oocytes and associated follicle cells of two species of amphineurans (Mollusca) Mopalia muscosa and Chaetopleura apiculata have been studied by techniques of light and electron microscopy. In addition to the regularly occurring organelles, the ooplasm of young oocytes contains large, randomly situated, basophilic regions. These regions are not demonstrable in mature eggs.As oocytes differentiate, lipid, pigment and protein‐carbohydrate yolk bodies accumulate within the ooplasm. Concomitant with the appearance of pigment and the protein carbohydrate containing yolk bodies, the saccules of the Golgi complex become filled with a dense material. Associated with the Golgi complex are cisternae of the rough endoplasmic reticulum which are filled with an electron opaque substance which is thought to be composed of protein synthesized by this organelle. That portion of the cisternae of the endoplasmic reticulum facing the Golgi complex shows evaginations. These evaginations are thought to finalize into protein containing vesicles that subsequently fuse with the Golgi complex. Thus, the Golgi complex in these oocytes might serve as a center for packaging and concentrating the protein used in the construction of the protein containing pigment or protein‐carbohydrate yolk bodies. The suggestion is made that the Golgi complex may also synthesize the carbohydrate portion of the formentioned yolk bodies.In an adnuclear position in young oocytes are some acid mucopolysaccharide containing vacuolar bodies. In mature eggs, these structures are found within the peripheral ooplasm and we have referred to them as cortical granules. There is no alteration of these cortical granules during sperm activation.
Ultrastructure of thymic myoid cells
Authors: Bockman Dale E. , Winborn William B. 
Published: February 2005

AbstractMature myoid cells in the parenchyma of reptilian thymus contain all the organelles typical of striated muscle. The presence of both immature and degenerating stages indicates a turnover of myoid cells in the adult thymus. In the earlier stages of differentiation myoid cells resemble thymic epithelial cells. A close parallel exists between developing myoid cells, skeletal muscle differentiating in vitro, rhabdomyoma and rhabdomyosarcoma. Elaborate lattice‐like structures are formed by transverse tubules. These structures are compared with similar configurations which have been described in muscle and mitochondrial cristae.