bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructure of Mehlis' gland in the lung fluke, Paragonimus ohirai (Trematoda: Troglotrematidae)
Authors: Orido Yasuhide 
Published: February 2005

AbstractMehlis' gland of a digenetic trematode, Paragonimus ohirai, is composed of two types of secretory cells, DB and CB. The less abundant type (DB) produces dense bodies, with the cytoplasm characterized by greatly distended cisternae of rough endoplasmic reticulum. The other type (CB) synthesizes clear, vesicular bodies. Its cytoplasm contains numerous mitochondria, rough endoplasmic reticulum with narrow cisternae, and abundant Golgi complexes. Processes of the two cell types converge on the ootype‐proximal uterine wall, pass through the epithelium, and finally open into the lumen. These proximal processes contain longitudinally arranged microtubules whose luminal ends are anchored to the epithelium by ring‐form septate desmosomes. According to the distribution of the two types of processes, three different zones (DB, mixed, and CB) can be recognized within the epithelia. As the CB processes enter the lumen predominantly beyond the uterine valve region, this cell may produce secretions required for egg shell maturation or hardening. The role of DB cells (which enter the lumen more commonly in the ootype near the oviduct) remains unknown.
Rickettsiae‐like structures in the larval salivary gland cells of Drosophila auraria
Authors: Thomopoulos George N. , Neophytou Elefterios P. , Limberi‐Thomopoulos Stella 
Published: February 2005

AbstractRickettsiae‐like structures were found in the salivary gland cells of Drosophila auraria during different larval and prepupal developmental stages, from the early 3rd instar up to 14 hr after spiracle inversion. These microorganisms are surrounded by a membrane, are constantly intracellular, and occur singly or in groups. Their widespread occurrence in various tissues of other Drosophila species indicates that they can be considered as symbionts, but their actual functional significance (if any) is unknown.
Composition of external setae during regeneration and transformation of the bilaterally asymmetric claws of the snapping shrimp, Alpheus heterochelis
Authors: Read A. T. , Govind C. K. 
Published: February 2005

AbstractThe paired thoracic chelipeds or claws of adult snapping shrimp, Alpheus heterochelis, are bilaterally asymmetric, consisting of an enlarged and elaborate, sound‐producing major (snapper) claw and a much smaller minor (pincer) claw. These paired claws vary in the composition of their external sensilla. Both possess long serrulate and simple short setae but the snapper also have plumose setae and long serrulate setae on the plunger. The pincers differ in having short serrulate setae and, in males alone, a prominent fringe of plumoserrate setae. During regeneration of each claw type, these setal structures are gradually added over three molts to reach the pristine condition. The long serrulate and simple short setae appear first, being seen in intermolt limb buds and commonly in both claws. Setae exclusive to each claw, i.e., plumoserrate and short serrulate in the pincer and plumose and long serrulate on the plunger in the snapper, appear sparsely in either the regenerated 1st or 2nd postmolt claw, they proliferate in the subsequent 2nd or 3rd postmolt claw. Transformation of the pincer claw to the snapper type begins in the 1st postmolt stage with the loss of pincer setae and addition of snapper setae and is completed by the 3rd postmolt stage. Since changes in composition of the external sensilla are restricted to postmolt stages, the underlying hypodermis is presumably being remodeled during proecdysis.
Ultrastructure of the atrioventricular valve and ventricular endo‐ and myocardium of the tigerfish, Hydrocynus forskahlii
Authors: Nel P. P. C. , Nel Maria M. , de Wit L. J. Duyvené 
Published: February 2005

AbstractGeneral ultrastructural properties of the atrioventricular valve and the endo‐ and myocardium of the tigerfish Hydrocynus forskahlii add further information to our knowledge of fish heart morphology. Small pieces of tissue from the heart of H. forskhalii were immersion‐fixed in 3% glutaraldehyde in Sörensen's phosphate buffer. Samples were postfixed in 1% osmium tetroxide and processed for transmission electron microscopy using standard techniques. The atrioventricular valve consists of dense collagen and fibroblasts lying between two layers of squamous endothelial cells. The ventricular endothelium consists of squamous cells with large nuclei protruding into the lumen of the ventricle. These cells lie on a basal lamina which overlies loose collagen in the subendothelial space. The ventricular myocardium is built up of distinctive nucleated fibres. Mitochondria, ribosomes, and glycogen are abundant in the sarcoplasm. Less conspicuous intercalated discs with no typical, steplike pattern are found between the myocardial cells. The Z lines as well as the I and A bands are clearly visible. The M lines are prominent, but the most important feature is the N line which is found on either side of the Z line in the lateral parts of the I band. The current research clearly underlines the fact that cardiac ultrastructure presents considerable diversity in different fish species.
Development of the glycogen body of the Japanese quail, Coturnix japonica: II. Observations of electron microscopy
Authors: De Gennaro Louis D. , Benzo Camillo A. 
Published: February 2005

AbstractTransmission electron microscopic observations of the relationships of the cells of the glycogen body and those of nervous tissue in the lumbosacral spinal cord show that one day after hatching, glycogen cells at the lateral margins of the glycogen body lie in close association with elements of the neuropil in the adjacent spinal cord. Glycogen cells and their processes appear to extend into the neuropil, where they contact other glycogen cells, blood vessels, neurons, and neuroglia. Junctional complexes and synapses occur among glycogen cells, astrocytes, and oligodendrocytes. Other indications of specialized activities were surmised by the presence of annulate lamellae in continuity with extensive arrays of smooth endoplasmic reticulum in several glycogen cells. These observations enhance our earlier views that cells of the avian glycogen body are metabolically active in the synthesis and degradation of glycogen for neuronal support and myelination in the central nervous system.
Carbonic anhydrase activity in kidney and lower intestine of the European starling
Authors: Laverty Gary , Alberici Mary 
Published: February 2005

AbstractA histochemical investigation of kidney and lower intestine of the European starling (Sturnus vulgaris) shows no carbonic anhydrase activity in proximal convoluted tubules, although activity is seen in similarly prepared sections of rat proximal tubules. Early distal tubule cells in the starling are stained throughout the cytoplasm and at the apical and highly infolded basolateral membranes. Late distal tubules lose apical activity and have reduced basolateral infolding, resulting in less intense staining. Darkly stained intercalated cells appear in the connecting tubules and cortical collecting ducts. Both of these segments also show intense basolateral staining. Medullary cones of the starling are highly organized, with central zones containing unstained thin descending limbs of loops of Henle, surrounded by both medullary collecting ducts with only scattered cells staining for enzyme, and by thick ascending limb segments. The latter contain many uniformly stained cells intermingled with occasional unstained cells. Scattered cells of the starling colonic villi demonstrate intense apical brush border membrane staining as well as cytoplasmic staining. Cells lining the cloaca stain less intensely. A biochemical assay for carbonic anhydrase was used to quantify enzyme activity in these tissues. Starling kidney contained 1.96 ± 0.33 (mean ± SEM) enzyme units/mg protein, less than half the activity seen in rat kidney. Stripped colonic epithelium contained 0.66 ± 0.15 enzyme units/mg protein. These quantitative results correlate well with the interpretations derived from the histochemical observations. The lack of proximal tubule carbonic anhydrase activity suggests that the avian kidney relies more on distal nephron segments to achieve net acidification of the urine.
Spermiogenesis in Odontophrynus cultripes (Amphibia, Anura, Leptodactylidae): Ultrastructural and cytochemical studies of proteins using E‐PTA
Authors: Báo Sônia N. , Dalton Gustavo C. , de Oliveira Sergio F. 
Published: February 2005

AbstractSpermiogenesis in the South American leptodactylid frog Odontophrynus cultripes was analyzed ultrastructurally. The spermatids undergo morphological modification while still enclosed in microtubule‐rich processes of Sertoli cells. Electron‐dense plates resembling junctional structures appear in regions at which the spermatids lie in close contact with the surface of Sertoli cell processes. Spermatid differentiation can be divided into five distinct stages based mainly on chromatin condensation. In the late stages, the densely compacted chromatin loses reactivity to ethanolic phosphotungstic acid (E‐PTA). Helical arrangements of microtubules appear in the cytoplasm that surrounds the spermatid nucleus after the second stage. The acrosomal vesicle differentiates into a cone‐shaped acrosome that caps the anterior region of the nucleus. The connecting piece, located in the flagellum implantation zone, has transverse striations, and is continuous with the axial rod. The tail is formed by a 9 + 2 axoneme, an undulating membrane, and an axial rod that is rich in basic proteins as demonstrated by E‐PTA staining.
The functional anatomy of the shoulder in the European starling (Sturnus vulgaris)
Authors: Dial Kenneth P. , Goslow G. E. , Jenkins Farish A. 
Published: February 2005

AbstractThe excursions of wing elements and the activity of eleven shoulder muscles were studied by cineradiography and electromyography in European starlings (Sturnus vulgaris) flying in a wind tunnel at speeds of 9–20 m s−1.At the beginning of downstroke the humerus is elevated 80–90° above horizontal, and both elbow and wrist are extended to 90° or less. During downstroke, protraction of the humerus (55°) remains constant; elbow and wrist are maximally extended (120° and 160°, respectively) as the humerus passes through a horizontal orientation. During the downstroke‐upstroke transition humeral depression ceases (at about 20° below horizontal) and the humerus begins to retract. However, depression of the distal wing continues by rotation of the humerus and adduction of the carpometacarpus. Humeral retraction (to within about 30° of the body axis) is completed early in upstroke, accompanied by flexion of the elbow and carpometacarpus. Thereafter the humerus begins to protract as elevation continues. At mid‐upstroke a rapid counterrotation of the humerus reorients the ventral surface of the wing to face laterad; extension of the elbow and carpometacarpus are initiated sequentially. The upstroke‐downstroke transition is characterized by further extension of the elbow and carpometacarpus, and the completion of humeral protraction.Patterns of electromyographic activity primarily coincide with the transitional phases of the wingbeat cycle rather than being confined to downstroke or upstroke. Thus, the major downstroke muscles (pectoralis, coracobrachialis caudalis, sternocoracoideus, subscapularis, and humerotriceps) are activated in late upstroke to decelerate, extend, and reaccelerate the wing for the subsequent downstroke; electromyographic activity ends well before the downstroke is completed. Similarly, the upstroke muscles (supracoracoideus, deltoideus major) are activated in late downstroke to decelerate and then reaccelerate the wing into the upstroke; these muscles are deactivated by mid‐upstroke. Only two muscles (scapulohumeralis caudalis, scapulotriceps) exhibit electromyographic activity exclusively during the downstroke. Starlings exhibit a functional partitioning of the two heads of the triceps (the humerotriceps acts with the pectoralis group, and does not overlap with the scapulotriceps). The biphasic pattern of the biceps brachii appears to correspond to this partitioning.
New data on the osteology of some species of Bregmaceros (Teleostei, Gadiformes)
Authors: Świdnicki Jacek 
Published: February 2005

AbstractOsteology of four extant species of Bregmacerotidae, Bregmaceros houdei, B. bathymaster, B. japonicus, and B. macclellandi, is described for the first time. The osteological analysis enables the recognition of two groups: (1) B. houdei and B. bathymaster, and (2) B. japonicus and B. macclellandi. Considerable differences in the structure of skull, and pectoral and pelvic girdles among the species indicate the existence of at least two phyletic lines within the genus. Knowledge of the skeleton may be of great importance for the taxonomy of fossil and extant species of Bregmaceros.
Structure and sympathetic innervation of the intracranial arteries in the giraffe (Giraffa camelopardalis)
Authors: Kimani James Kirumbi , Opole Isaac O. , Ogeng'O Julius A. 
Published: February 2005

AbstractFluorescence histochemistry discloses that the carotid rete mirabile in the giraffe has a poor sympathetic innervation. In contrast, the efferent artery of the rete (internal carotid artery) and the cerebral arteries show moderate sympathetic innervation. A certain degree of regional variability was noted in which the rostral arteries (anterior and middle cerebral) receive more sympathetic nerves than the caudal (posterior communicating and basilar) arteries. The sympathetic nerves on the giraffe cerebral vessels may constitute part of a host of mechanisms by which regional blood flow to the brain is regulated. Conversely, the paucity of sympathetic innervation of the carotid rete mirabile may indicate that this structure does not play an active role in vasoconstrictor responses during postural changes of the head.
Comments on the pelvic appendicular vestiges in an amphisbaenian: Blanus cinereus (Reptilia, squamata)
Authors: Renous Sabine , Gasc Jean‐Pierre , Raynaud Albert 
Published: February 2005

AbstractA detailed description of muscular and skeletal features of the pelvi‐cloacal region of the amphisbaenian Blanus cinereus reveals that the species has real hind limbs articulating with a real pelvic girdle. Arguments support this homology: 1) a link with the vertebral column; 2) a movable articulation, showing all the features of a diarthrosis, between the femur and the acetabulum; 3) all the long bone characteristics for the femur which distally bears a horny element. The morphological peculiarities of the amphisbaenian pelvic girdle are generally close to those of lizards, but the pubis seems to be more reduced. For the same number of precloacal vertebrae, the amphisbaenians have more appendicular elements than lizards have, and this composition recalls that of the Leptotyphlopidae, Aniliidae, and Boidae. The account provides more information concerning the aponeuro‐tendinous system associated to the skeleton of the girdle and the hindlimb, the musculature, and the interrelations between the different structures of the pelvi‐cloacal region.
Structure and morphogenesis of the eggshell and micropylar apparatus in the olive fly, Dacus oleae (Diptera: Tephritidae)
Authors: Mouzaki Despina G. , Zarani Flora E. , Margaritis Lukas H. 
Published: February 2005

AbstractThe egg of the olive fly, Dacus oleae (Diptera, Tephritidae), is laid inside olives and the larva eventually destroys the fruit. The oocyte is surrounded by several distinct layers which are produced during choriogenesis. The chorion covering the main body of the egg outside of the vitelline membrane includes a “wax” layer, an innermost chorionic layer, an endochorion consisting of inner and outer layers separated by pillars and cavities similar to their counterparts in Drosophila melanogaster, as well as inner and outer exochorionic layers. The anterior pole is shaped like an inverted cup, which is chiefly hollow around its base and has very large openings communicating with the environment. Holes through the surface of the endochorion result from deposition of endochorionic substance around follicular cell microvilli. An opening at the apex of the cup provides an entrance for sperm entering the micropylar canal, which traverses the endochorion and continues into a “pocket” in a thickened vitelline protrusion. The micropylar canal is formed by deposition of endochorion and vitelline membrane around an elongated pair of follicular cell extensions. These extensions later degenerate and leave an empty canal about 5 μm in diameter and the narrower pocket about 1 μm in diameter. Respiration is thought to be facilitated by openings at the base of the anterior pole as well as by openings through the “plastron” around the main body of the shell.
Hind limb scaling in birds and other theropods: Implications for terrestrial locomotion
Authors: Gatesy Stephen M. 
Published: February 2005

AbstractAn analysis of hind limb skeletal elements of non‐avian theropods and ground‐dwelling birds was performed to reveal patterns of change in shape and proportion with size. When femora of equal length are compared, birds exhibit a significantly larger midshaft diameter than non‐avian theropods. As total limb length increases, avian femora become relatively shorter (negative allometry), while those of non‐avian theropods become relatively longer (positive allometry). Avian femoral/tibiotarsal ratios are all below 0.8 and decrease with limb size, whereas ratios of non‐avian theropods are well above 0.8 and tend to increase with limb size. In addition, avian femora exhibit a unique diameter/length relationship not seen in other theropod hind limb bones.Several studies have shown that within the avian limb, the short, robust femur resists bending to a far greater degree than the relatively longer, slimmer tibiotarsus. This is to be expected, as analyses of running birds show that the femur is oriented relatively perpendicular to the ground reaction force throughout the stride, which would subject it to high bending moments. When compared to birds, non‐avian theropods have relatively long, slender femora that do not seem to be built to withstand the forces associated with such an orientation. Reconstructing all non‐avian theropods in avian‐like poses (subhorizontal femur, knee well flexed) with avian locomotor kinematics (relatively little hip extension at most speeds) ignores major differences in scaling between these groups of organisms.
Ultrastructural study of the blood cells of the beluga whale,Delphinapterus leucas
Authors: Williams Charles Rogers , Chapman George B. , Blake Andrea S. 
Published: February 2005

AbstractGeneral cytological and ultrastructural features of cells found in the peripheral blood of three captive beluga whales (Delphinapterus leucas) are described. We noted all major peripheral cell types common to the circulation of mammalian species, including polymorphonuclear neutrophils, eosinophils, basophils, lymphocytes, and monocytes, as well as myelocytes, erythroblasts, and plasma cells. Platelets and two populations (normal and hypochromic) of red blood corpuscles were observed.
Programmed cell death in the wing of Orgyia leucostigma (lepidoptera: Lymantriidae)
Authors: Nardi James B. , Godfrey George L. , Bergstrom Rebecca A. 
Published: February 2005

AbstractProgrammed cell death is an integral and ubiquitous phenomenon of development that is responsible for the reduction of wing size in female moths of Orgyia leucostigma (Lymantriidae). Throughout larval and pupal life, cells of the wing epithelium proliferate and interact to form normal imaginal discs and pupal wings in both sexes. But at the onset of adult development, most cells in female O. leucostigma wings degenerate over a brief, 2‐day period. Lysosomes and autophagic vacuoles appear in cells of the wing epithelium shortly after it retracts from the pupal cuticle. Hemocytes actively participate in removing the resulting cellular debris. By contrast, epithelial cells in wings of developing adult males of O. leucostigma do not undergo massive cell death. Wing epithelium of female pupae transferred to male pupal hosts behaves autonomously in this foreign environment. By pupation, cells of the female wing apparently are committed to self‐destruct even in a male pupal environment. Normal interactions among epithelial cells within the plane of a wing monolayer as well as between the upper and lower monolayers of the wing are disrupted in female O. leucostigma by massive cell degeneration. Despite this disruption, the remaining cells of the wing contribute to the formation of a diminutive, but reasonably proportioned, adult wing with scales and veins.
Structure of the respiratory islets of accessory respiratory organs and their relationship with the gills in the climbing perch, Anabas testudineus (Teleostei, Perciformes)
Authors: Munshi J. S. D. , Hughes G. M. 
Published: February 2005

AbstractThe epithelial and sub‐epithelial organization of the accessory respiratory organs of Anabas testudineus has been compared with that of gills by using light and transmission electron microscopy. The details of vascular supply of respiratory islets (RI) and gill filaments and the presence of venous sinusoids in the two systems suggest that the RI have been derived from gill filaments and lamellae. The biserial arrangement of transverse capillaries (TC) in the respiratory islets (RI) is evident under the scanning electron microscope and their homology with the gill filaments and their secondary lamellae has been established. The two sets of transverse capillaries of respiratory islets have been derived either from embryonic transverse or marginal channels of two sets of lamellae of a gill filament. These capillaries with their endothelial septate valves and tongue‐like processes offer resistance to blood flow.Gill filaments have two vascular pathways, arterio‐arterial and arterio‐venous. However, the RI of accessory respiratory organs contain the arterio‐venous pathways. This arrangement as well as the septate transverse capillaries may lower the “pulmonary” blood pressure considerably.Two types of mitochondria‐rich cells are identified: i) chloride cells with flat microvilli bearing surfaces, devoid of apical pit and (ii) an elongated cell type with sac‐like endoplasmic reticulum, with apical pit that comes into close contact with the complex matrix of macrophages, lymphocytes and other loose cells of the epithelium. These cells may be associated with detoxification of the internal media of fish inhabiting foul waters.
Ovary of the seahorse, Hippocampus erectus
Authors: Selman Kelly , Wallace Robin A. , Player Denifield 
Published: February 2005

AbstractThe ovary of the seahorse, Hippocampus erectus, is a cylindrical tube bounded by an outer layer consisting of a mesothelium and muscular wall and by an inner luminal epithelium, with a single row of developing follicles sandwiched between the two layers. Follicles are produced by a germinal ridge, which contains oogonia, early oocytes, and prefollicle cells, and which runs along the length of the ovary. The germinal ridge is an outpocketing of the luminal epithelium, as indicated by a continuous underlying basal lamina. Prefollicle cells invest diplotene oocytes and the complex eventually pinches off the germinal ridge as a primordial follicle surrounded by a basal lamina derived from the germinal ridge. Subsequent investment of the primordial follicle by elements of the theca complete the process of folliculogenesis. H. erectus has two ovaries and each ovary has two dorsally located germinal ridges. Thus, in each ovary the derived follicular lamina is bilaterally symmetrical: two temporally and spatially arranged sequences of developing follicles are produced, with the largest follicles found along the ventral midline of the ovary. The advantages of developmental, kinetic, and systemic analyses of these unusual ovaries are indicated.