bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional anatomy of the secondary copulatory apparatus of the male dragonfly Tramea virginia (Odonata: Anisoptera)
Authors: Andrew R. J. , Tembhare D. B. 
Published: February 2005

AbstractIn the dragonfly Tramea virginia, the secondary copularoty apparatus (SCA) on the venter of the second and third abdominal segments consists of the anterior and posterior laminae, a pair of gential lobes and hamules, the ligula, genital fossa, supporting frame work, and the four segmented, highly specialized penis. The penis head represnts the distal or fourth segment of the penis and bears paired lateral and apical lobes and a medial process. The medial process includes a sperm reservior, a short sperm tube, and paired cornua and inner lobes. The sperm reservoir opens into the sperm tube which bears a terminal orifice between the inner lobes. Gross morphology of the SCA of T. virginia is similar to that of other libellulids except that the gential lobes and hamules are comparatively large in size, the ligula is triangular in shape with an apical flat rectangular lobe and stiff basal setae, the penis bears a pair of cuticular denticles below the spur of the second segment, the apical lobes are inflatable without spines and bristles, and the cornua with smooth outer and spiny inner surface collectively signifying the species‐specific anatomical features and the functional specialization for sperm transfer and removal. © 1993 Wiley‐Liss, Inc.
Ultrastructure of the pseudobranch in the euryhaline Cyprinodontid fish, Rivulus marmoratus
Authors: King Judy A. C. , Smith Peter R. , Ashcraft Jan C. , Dibona Donald R. 
Published: February 2005

AbstractThe ultrastructure of the pseudobranch of the euryhaline, self‐fertilizing fish, Rivulus marmoratus (Cyprinodontidae) was studied with thin sectio and freeze‐fracture transmission electron microscopy. In specimens raised from birth in 1% or 200% seawater, the pseudobranch contains two mitochondria‐rich cell types, pseudobranchial cells and chloride cells, each of which has an extensive tubular system. Chloride cells only occur on the lateral aspects of the pseudobranch, with their apical crypts open to the environment. Apical crypt invagination to a “pit” structure and multicellular complexes occur in both salinity extremes. The ultrastructure of chloride cells in 1% and 200% SW is consistent with that described previously in the opercular epithelium, opercular skin, and gill of this species; elaboration of mitochondria and basolateral membrane accompanies increased environmental salinity (King et al.: Cell and Tissue Research 257:367–377, 1989). Pseudobranchial cells constitute the majority of the cells; they do not extend to the surface but have a more organized tubular system that is continuous with the basal membrane. These cells do not exhibit ultrastructural changes in response to increased salinity. © 1993 Wiley‐Liss, Inc.
Ultrastructure of the light organ and immunocytochemical localization of luciferase in luminescent marine ostracods (Crustacea: Ostracoda: Cypridinidae)
Authors: Huvard Andrea L. 
Published: February 2005

AbstractThe ultrastructure of the upper lip, which is the location of the light organ in luminescent ostracods, is described for two species of marine ostracods (Vargula graminicola, and V. tsujii). The light organ contains four primary cell types (here designated A–D) readily identified both by the types of vesicles that they contain and their location. Cell type A, restricted to the center of the light organ, has vesicles that are homogeneous throughout. Cell type B has vesicles with a single electron‐dense central area. This cell is most common in the lateral regions but is also found in the tusks. Immunocytochemical experiments revealed that luciferase is found in B cells, but not in any other cells or in control specimens. Cell type C has vesicles containing many electrondense microstructures; this cell type is the least common and is found along with B cells within the lateral margins of the light organ. Cell type D has granulated vesicles and is restricted to the tusks. Metachromatic staining with toluidine blue suggests that the vesicles contain acidic mucosubstances. The cells of the light organ are very long (360–460 μm) and extend through its entire length. The cells found exclusively in the tusks are shorter (ea. 150 μm). All cells possess similar polarity: proximal synthesis, middle transitional, and distal secretory regions. These cells terminate ventrally at nozzles on the anterior portion of the upper lip, and on the tusks. The upper lip and light organ possess two large longitudinal muscles, a central muscle, and several smaller “bridle” muscles that attach onto sclerotized ridges. Various hypotheses for the storage and secretion of light organ materials are suggested relative to these morphological data. © 1993 Wiley‐Liss, Inc.
Kidney of the sumatran rhinoceros, Dicerorhinus sumatrensis
Authors: Maluf N. S. R. 
Published: February 2005

AbstractThe kidney of Diceros sumatrensis has the rhinocerotic form and lobation. The ureter divides intrarenally into two fibromuscular conduits which receive, at separate loci, the terminal collecting ducts of the lobes. The kidney is 67% cortex. Total renal mass is 0.46% of body mass. There are about 34 lobes and 23 primary orifices at the conduits. Glomeruli are relatively small and of the same size across the cortex. They number about 14.6 million in one kidney but the glomerular mass is relatively low. Unlike other rhinocerotic species, the kidney of D. sumatrensis lacks interlobar septa. The interlobar arteries nevertheless enter the renal parenchymas as in the other rhinoceroses, i.e., between the cortices of adjacent lobes rather than in the common mammalian manner between cortex and medulla. Thus, internal “perforator” arteries pass from cortical periphery to interior giving off cortical twigs on their way to the corticomedullary border, along which they branch while releasing centrifugal arteries back toward the cortical periphery. The arcuate veins are wide centrally where they enter the paraconduital veins. The latter form prominent central anastomoses between the large interlobar veins. © 1993 Wiley‐Liss, Inc.
Ultrastructure and protein uptake of the embryonic trophotaeniae of four species of goodeid fishes (Teleostei: Atheriniformes)
Authors: Hollenberg Frank , Wourms J. P. 
Published: February 2005

AbstractEmbryos of most species within the viviparous teleost family Goodeidae develop characteristics perianal processes that are considered to be derivatives of the embryonic hindgut. These processes, termed trophotaeniae, are covered with an epithelium that is continuous with the absorptive epithelium lining the hindgut. Gestation is intraovarian, and trophotaeniae mediate the uptake of maternally provided nutrients into the embryo from the ovarian fluid. Ultrastructural examination of the trophotaeniae of four goodeid species reveals substantial diversity in the organization of the epithelium within the family. The trophotaeniae of Alloophorus robustus, Zoogoneticus quitzeoensis, and Ilyodon furcidens have morphological features associated with the endocytosis of macromolecules and can be shown to endocytose the exogenous protein tracer horseradish peroxidase (HRP) rapidly. The trophotaenial epithelia of these species differ from one another with respect to other morphological features such as cell height, organization of the brush border, and the complexity of the intercellular spaces. The trophotaeniae of Goodea atripinnis lack an endocytotic apparatus and do not endocytose HRP. However, the overall organization of G. atripinnis trophotaenial cells suggests a function as a transporting epithelium. The cells have a dense brush border, numerous mitochondria, and many mitochondria that are enveloped by lamellar sheets of intracellular membrane.Post‐fixation with osmium and potassium ferrocyanide reveals a marked difference in the complexity of the subepithelial connective tissue. Alloophorus robustus and Z. quitzeoensis exhibit an extremely electron‐dense ground substance containing many acellular components. Goodea atripinnis exhibits an electron‐lucid ground substance with few acellular components. © 1994 Wiley‐Liss, Inc.
Molar surface morphology in Streptocephalus coomansi (Crustacea: Branchiopoda: Anostraca)
Authors: Brendonck Luc 
Published: February 2005

AbstractExcept for the posterio‐dorsal margin, the circumference of the molar surface exhibits flagellated processes which become simple at the posterioventral margin. Four topographic regions are distinguished: (A) a posterodorsal region, (B) a peripheral region, (C) a transitional zone, and (D) a central region. The postero‐dorsal region of the left mandible has one row of widely spaced, stout, conical teeth, while in the right mandible two rows of slender teeth, which become multi‐branched anteriorly, are present. The peripheral molar region stretches between the bordering flagellated processes and the central region and consists of several parallel, dorso‐ventral rows of armed teeth. The maximum number of teeth in one dorso‐ventral row is higher at the ventral than at the dorsal side and in the left than in the right mandible. In the transitional zone, the number of cusps on each tooth is progressively reduced. The central region, a perforated thickened cuticular plate, extends over the majority of the molar surface. This region is unique among the anostracans studied in this respect and may reflect a different feeding ecology. The strongly diversified molar surface probably allows the species to exploit a wide trophic spectrum. It remains to be tested if these observations may be extrapolated to the entire genus. © 1994 Wiley‐Liss, Inc.
External morphology of the larvae of Ephydra (Hydropyrus) hians (Diptera: Ephydridae)
Authors: Cash‐Clark Cora E. , Bradley Timothy J. 
Published: February 2005

AbstractScanning electron microscopy is used to describe the ultrastructure of morphological features related to feeding, locomotion, respiration, and pigmentation in second‐ and third‐instar larvae of Ephydra hians (Ephydridae: Diptera). Using larvae fixed with the head extended, the ultrastructural details of the mandibles, maxillary papilli, and antennae are described for the first time. The larvae possess finger‐like projections at the anterior spiracle and a distensible bifurcated siphon at the posterior spiracle. Slit‐like openings are found on each. The second‐ and third‐instar larvae can be differentiated on the basis of dorsal pigmentation associated with extensive patches of spines. The larvae have regional specializations in spine distribution, particularly on the ventral and dorsal body surfaces, and the prolegs. © 1994 Wiley‐Liss, Inc.
Buoyancy studies and microscopy of skin and subdermal extracellular matrix of the antarctic snailfish, Paraliparis devriesi
Authors: Eastman Joseph T. , Hikida Robert S. , Devries Arthur L. 
Published: February 2005

AbstractThe Antarctic snailfish Paraliparis devriesi (Liparididae) occupies an epibenthic habitat at a depth of 500–650 m in the subzero waters of McMurdo Sound, Antarctica. Although lacking a swim bladder, this species is neutrally buoyant through the combined effects of reduced skeletal ossification and expansion of a watery gelatinous subdermal extracellular matrix (SECM). The SECM serves as a low density buoyancy agent. It comprises a mean of 33.8% of the body weight, the largest known proportion of any adult fish. The SECM is loose connective tissue dominated by ground substance consisting of glycosaminoglycans, especially hyaluronic acid, and immobilized water. Although the SECM is 97% water, elevated levels of NaCl provide an osmotic strength greater than that of other body fluids. Only small amounts of antifreeze compounds have been identified in P. devriesi; therefore, freezing avoidance may result from the combined effects of antifreezes and the elevated osmolality of body fluids. The skin overlying the SECM is thin (85–200 μm) and loose, and unlike most other fishes, the epidermis is several times thicker than the dermis. The midepidermis, has a distinctive layer of vacuolated club cells of unknown function. Light and electron microscopy indicate that the skin is unspecialized for protection against entry of ice. © 1994 Wiley‐Liss, Inc.
Comparative morphology of the myomeres and axial skeleton in four genera of centrarchid fishes
Authors: Jayne Bruce C. , Lauder George V. 
Published: February 2005

AbstractWe used X‐rays and dissection of myotomes to quantify the axial morphology of four species of centrarchid fishes (Micropterus salmoides, Ambloplites rupestris, Pomoxis nigromaculatus, and Lepomis macrochirus). Proceeding from dorsal to ventral, we designated the two epaxial and two hypaxial protions of the myomeres AB, BC, CD, and DE, respectively. For each of 11 myomeres, spaced at 10% increments along the length of the fish, a total of 14 variables described the length and orientation of each portion, the dorsalventral symmetry, and the overall height and longitudinal span of the entire myomere. Nine variables described the lengths, orientation, and symmetry of the vertebral centra, neural and hemal spines, and ribs. Analysis of variance revealed that, with one exception, all 23 morphological variables varied significantly both among species and among longitudinal locations within a species. However, the extent of longitudinal and interspecific variance differed considerably among different variables. Maximal myomeric height ranged from about 45% of the standard length (SL) in Lepomis to 27% SL in Micropterus. Longitudinal and interspecific increases in overall height of the trunk myomeres resulted primarily from greater lengths of CD. Compared to other portions of the myomere, the length of BC was most conservative both longitudinally and interspecifically. Dorsal‐ventral symmetry of the myomeres and axial skeleton was greater in the caudal region than in the trunk in all species, and the myomeric morphology diverged least among species in the posterior caudal region. The overall longitudinal span of superficial myomeric landmarks varied from 6% to 18% SL, and, including the deep portions of the myomeres, the longitudinal span varied from about 7 to 10 vertebrae. Within each of the species, myomeric and skeletal variables were often not significantly correlated, but for the pooled data of all species there were usually highly significant correlations between myomeric and skeletal morphology. For example, strong correlations existed between BC and the underlying neural spines, and between CD and the underlying ribs and hemal spines. In contrast, the longitudinal spans of entire myomeres and underlying axial skeletal segments were only weakly associated. © 1994 Wiley‐Liss, Inc.
Placental structure of the Australian lizard, Niveoscincus metallicus (Squamata: Scincidae)
Authors: Stewart James R. , Thompson Michael B. 
Published: February 2005

AbstractA unique type of reptilian allantoplacenta was described by Weekes [1930] (Proc. Linn. Soc. N.S.W. 55:550–576) from a single embryonic stage of the Tasmanian skink, Niveoscincus ocellatus (as Lygosoma (Liolepisma) ocellatum). She also assigned N. metallicus to this placental category but did not provide a description. Here we provide a description of allantoplacentation and yolk sac placentation of N. metallicus. The allantoplacenta is regionally differentiated and differs from other reptilian allantoplacentae by the presence of a zone of hypertrophied chorionic epithelial cells in apposition to uterine blood vessels which are contained within ridges formed from uterine epithelial cells. This zone is located dorsolaterally along the long axis of the egg at the upper margin of the yolk sac. In contrast, the cells of the chorionic epithelium dorsal to the embryo are smaller and the uterine blood vessels are not contained in ridges. The definitive yolk sac placenta is an omphaloplacenta. The bilaminar omphalopleure of the omphaloplacenta consists of an outer layer of cuboidal or columnar cells. Cells of the uterine epithelium of the omphaloplacenta are cuboidal or columnar in shape and are supported by uterine blood vessels. © 1994 Wiley‐Liss, Inc.
Cellular details of the midgut of Cryptocellus boneti (Arachnida: Ricinulei)
Authors: Ludwig Mario , Palacios‐Vargas José G. , Albertif Gerd 
Published: February 2005

AbstractThe midgut of Cryptocellus boneti was studied by light and electron microscopy. The epithelia of the diverticula and of the anterior part of the midgut tube are composed of two cell types: digestive and secretory. In contrast, the epithelia of posterior part of the midgut tube and of the stercoral pocket consist of one type of cells only. In some places, parts of the midgut system are connected by an intermediate tissue. Digestive cells are characterized by an apical system of tubules, nutritional vacuoles, and spherites; characteristic features of secretory cells are secretory granules and a prominent rough endoplasmic reticulum. Cells of the midgut tube appear not to be involved in the absorption of food. © 1994 Wiley‐Liss, Inc.
Organization of motoneurons innervating the axial musculature of the brown caiman (Caiman crocodilus fuscus)
Authors: Murakami Gen , Nakasone Tadashi , Akita Keiichi , Kato Yutaka , Sato Iwao , Shimada Kazuyuki 
Published: February 2005

AbstractThe primary divisions of the spinal nerve in the brown caiman characteristically show the following features: (1) the medial ramus was lies in the thoraco‐lumbar and caudal regions, and (2) the first cervical and hypoglossal nerves form a single nerve complex from which the ventral and dorsal rami extend. Intramuscular injections of horseradish peroxidase (HRP) established the positions of motoneurons whose axons followed the primary rami. In the ventral horn of the thoracic and caudal spinal cord, the motoneurons of the medial ramus lie ventrally. These motoneurons lie between the epaxial and hypaxial motoneurons. At the spinomedullary junction, the pools of motoneurons innervating the infrahyoid, lingual, and dorsal muscles have a somatotopic organization similar to that observed in the thoraco‐lumbar and caudal regions. Thus clear somatotopic organization of the motoneurons that innervate the axial musculature exists at all spinal levels. © 1994 Wiley‐Liss, Inc.
Factors governing the stickiness of cribellar prey capture threads in the spider family Uloboridae
Authors: Opell Brent D. 
Published: February 2005

AbstractThe surface of a cribellar prey capture thread is formed of thousands of fine, looped fibrils, each issuing from one of the spigots on an oval spinning plate termed the cribellum. This plesiomorphic capture thread is retained by members of the family Uloboridae, in which its stickiness differs among genera. An examination of five cribellar thread features in nine uloborid species shows that only the number of fibrils that form a thread explains these differences in thread stickiness. Neither the physical features of these fibrils, nor the manner in which they are combined to form threads differs among species. Threads produced by orb‐weaving species contain fewer fibrils than those produced by species that build reduced webs. Relative to spider weight, the number of fibrils that form a cribellar thread is greatest in simple‐web species of the genusMiagrammopes, less in triangle‐web species of the genusHyptiotes, and least in orb‐weaving species representing five genera. A transformational analysis shows that change in the number of cribellum spigots is directly related to change in the stickiness of cribellar thread. This direct relationship between the material invested in a cribellar thread and its stickiness may have been a limiting factor that favored the switch from the dry cribellar threads of uloborids to the adhesive capture threads produced by other orb‐weaving families. © 1994 Wiley‐Liss, Inc.
Properties of twitch motor units of the ankle extensor muscles in the bullfrog Rana catesbeiana
Authors: Peters Susan E. 
Published: February 2005

AbstractA study of the mechanical properties of the twitch motor units in the ankle extensor muscles of bullfrogs was undertaken to expand our view of the diversity of motor unit properties among vertebrates. Two muscles were chosen that represent a wide range of extensor function: the plantaris longus (PL) is a large muscle providing most of the force for ankle extension in hopping and swimming, and the tibialis posticus (TP) is relatively small and may act as an ankle stabilizer or be primarily postural in function. Both muscles have highly fatigable motor units, but also some (especially in TP) low or non‐fatigable ones. Mean tetanic tensions of motor units in both muscles are relatively large as compared with those of mammals but are especially large in PL, No clear correlations were found between contraction times and either motor unit tetanic tensions or fatigability, nor did the motor units fall into clearly defined types based on any functional parameters. Overall contraction and relaxation times are slow compared with those of mammals and are somewhat slow compared to those of other frogs; unlike results from earlier studies, the large units of PL are slower than the small units of TP. This results in PL units reaching fused tetani at lower stimulus frequencies. The twitch/tetanus and force/frequency ratios in PL motor units are much larger than those of TP, giving PL units greater relative forces at lower stimulus rates. These results are discussed in the context of motor unit function. © 1994 Wiley‐Liss, Inc.
Relationship between muscle fiber types and sizes and muscle architectural properties in the mouse hindlimb
Authors: Burkholder Thomas J. , Fingado Brian , Baron Stephanie , Lieber Richard L. 
Published: February 2005

AbstractSkeletal muscle fiber and architectural properties both contribute to the functional behavior of a muscle. This study uses discriminant analysis and mathematical modeling to identify the structurally and functionally significant properties. The architectural properties of fiber length, muscle length, and pennation angle are found to be the most structurally significant parameters, whereas fiber length, muscle length, and fiber type distribution are found to be most functionally determining. Architectural speed and fiber type do not appear to be complimentary (i.e., the architectural determinant of sspeed, fiber length, is not associated with fibers of high intrinsic velocity). However, there does seem to be a synergistic relation between the two property classes and force production. Muscles with large physiological cross sectional areas (PCSAs) tend to contain a greater proportion of larger, faster fibers. Structurally or morphologically significant parameters are not always found to have a large functional effect. Pennation angle, though one of the most structurally significant variables, was found to have very little functional effect. © 1994 Wiley‐Liss, Inc.