bluuebunny/crossref_metadata_2025_split huggingface dataset:
A comparative study of the ultrastructure and mineralogy of calcified land snail eggs (Pulmonata: Stylommatophora)
Authors: Tompa Alex S. 
Published: February 2005

AbstractThis study indicates that eggs containing calcium carbonate crystals occur in at least 36 of the 65 known families of the land snails (class Gastropoda: order Stylommatophora). Eggs from 22 of these families were available for examination. The x‐ray diffraction data, available for the first time for 21 of these families, shows that these egg shells are all made of calcite only, or of a combination of calcite with smaller amounts of aragonite. All of the snail (body) shells examined were made of aragonite only. This is the first ultrastructural investigation of these egg shells, and it indicates that the eggs exhibit enough structural diversity to allow identification of parental animals to genus, and often to species level solely on the basis of egg shell ultrastructure.All of the calcified eggs may be divided into two groups: (1) partly calcified, with discrete crystals of CaCo3 dispersed in the jelly layer, and (2) heavily calcified, with a hard, brittle egg shell made of fused crystals of CaCO3 much like an avian egg. Both types of calcified eggs occur in oviparous as well as in ovoviviparous snails. Because of the wide distribution of calcified eggs in the Stylommatophora, and because of the occurrence of heavily calcified eggs in ancient families such as Partulidae, Endodontidae, and Zonitidae, the calcified egg is viewed as a primitive land snail trait associated with terrestrial adaptation. The function of the calcified egg shell, in addition to mechanical support of egg contents, is to supply the developing embryo with enough calcium to form the embryonic shell by the time of hatching.
The effect of the hormone(s) from the corpus allatum complex on the ovarian tissue of Oncopeltus fasclatus. A light and electron microscopic investigation
Authors: Schreiner Berit 
Published: February 2005

Abstract(1) In an animal where the corpus allatum complex is inhibited by glucose feeding, the ovariole develops to a certain size without yolk deposition in the oocytes. Histologically this can be registered as: (a) Lipid spheres are found in the young oocytes in the vicinity of the Balbiani body (as in young normal oocytes). However, this lipid decreases in amount and “new” lipid (from the fat body via haemolymph) is not deposited in the later oocytes. (b) No carbohydrate/protein yolk is formed. (c) Glycogen is not synthesized in the oocytes. (d) The follicle cells aggregate glycogen instead of lipid. (e) No qualitative differences have been observed regarding the contributions from the tropharium (the so‐called Type 1 vacuole, ribosomes, mitochondria, annulated lamellae: Schreiner, '77).(2) Implantation of a corpus allatum complex results in deposition of lipid, carbohydrate/protein and glycogen yolk. However, the restoration period differs histologically from the normal development as: (a) Glycogen appears in the oocyte earlier than normal, i.e., at Stage 4, while normally at Stage 6′. (b) Glycogen appears in the nutritive tube adjacent to the interfollicular plug cells. (c) Both the inner and outer layer of the ovariole sheath contain glycogen, the outer layer contains lipid spheres as well.
The oral apparatus of Tetrahymena pyriformis, Strain WH‐6. IV. Observations on the organization of microtubules and filaments in the isolated oral apparatus and the differential effect of potassium chloride on the stability of oral apparatus microtubules
Authors: Gavin R. H. 
Published: February 2005

AbstractThis report is an ultrastructural analysis of the organization of the isolated oral apparatus of Tetrahymena pyriformis, strain WH‐6, syngen 1. Attention has been focused on the organization of microtubules and filaments in oral apparatus membranelles. Oral apparatus membranellar basal bodies were characterized with respect to structural differentiations at the distal and proximal ends. The distal region of membranellar basal bodies contains the basal plate, accessory microtubules and filaments. The proximal end contains a dense material from which emanate accessory microtubules and filaments. There are at least two possibly three different arrangements of accessory structures at the proximal end of membranellar basal bodies. All membranellar basal bodies appear to have a dense material at the proximal end from which filaments emanate. Some of these basal bodies have accessory microtubules and filaments emanating from this dense material. A possible third arrangement is represented by basal bodies which have lateral projections, from the proximal end, of accessory microtubules and filaments which constitute cross or peripheral connectives. There are at least three examples of direct associations between oral apparatus microtubules and filaments: (1) filaments which form links between basal body triplet microtubules, (2) filaments which link the material of the basal plate to internal basal body microtubules, (3) filaments which link together microtubule bundles from membranellar connectives. KCI extraction of the isolated oral apparatus resulted in the selective solubilization of oral apparatus basal bodies, remnants of ciliary axonemes and fused basal plates. Based on their response to KCl extraction two distinct sets of morphologically similar microtubules can be identified: (a) microtubules which constitute the internal structure of basal bodies and ciliary axonemes, (b) microtubules which constitute the fiber connectives between basal bodies.
Studies on the gill ciliation of the American oyster Crassostrea virginica (Gmelin)
Authors: Ribelin Ben W. , Collier Albert 
Published: February 2005

AbstractLatero‐frontal, para‐latero‐frontal, and frontal ciliary tracts on the gill filaments of Crassostrea virginica (Gmelin) were studied with light microscopy and scanning electron microscopy. Latero‐frontal cirri are complex structures composed of varying numbers of paired cilia. The multiple pairs of cilia which constitute a single cirrus are closely appressed for a portion of their length; they then branch laterally from the central axis in a plume‐like fashion. Latero‐frontal cirri of adjacent gill filaments create a filtration sieve which should be capable of retaining particles smaller than 1 μm in diameter. Para‐latero‐frontal cilia are short, closely spaced cilia arranged as a staggered row along the frontal side of each tract of latero‐frontal cirri. Latero‐frontal cirri and para‐latero‐frontal cilia occur on ordinary, principal, and transitional gill filaments. Frontal ciliary tracts of ordinary filaments are divided into a central, ventrally directed coarse tract, flanked on either side by a dorsally directed fine ciliary tract. The coarse tract is covered by cirri which are comprised of five to eight cilia, while the fine frontal tracts are made up of individually functioning cilia. The frontal ciliary tracts of principal and transitional filaments bear only dorsally directed fine cilia. The unique direction of effective beat of the coarse frontal cirri of ordinary filaments, in combination with the action of fine frontal cilia and the strategic location of mucus producing cells, is used to describe a possible mechanism for the sorting of filtered particles.
Spermatozoa of Ciona intestinalis and analysis of ascidian fertilization
Authors: Woollacott Robert M. 
Published: February 2005

AbstractThe complex array of vestments which surrounds the ascidian oocyte indicates that spermatozoa of these urochordates may be highly modified to effect penetration through the egg‐envelopes and to achieve successful fusion with the female gamete. Examination of the spermatozoa of Ciona intestinalis reveals, however, that they lack an acrosomal vesicle and do not possess detectable amounts of actin. Furthermore, the spermatozoa do not undergo observable morphological alterations when exposed to ammoniated seawater, a treatment known to produce aggregation and an acrosome reaction in other organisms. Ciona spermatozoa do contain significant quantities of proteases. It is hypothesized that the localization of these enzymes may be related to the ridge‐like surface ornamentation which is observed as a component of the head region of Ciona spermatozoa.
Auditory systems of heteromyidae: Cochlear diversity
Authors: Webster Douglas B. , Webster Molly 
Published: February 2005

AbstractCochleae (125) from 26 species of the rodent family Heteromyidae (genera Dipodomys. Microdipodops, Perognathus, and Liomys) were compared. In Perognathus and Liomys the scala tympani in the apical portion is extremely narrow with a correspondingly minute helicotrema. In Liomys there is no bone separating scala tympani from spiral ganglion in the upper second and entire third turn. In all species studied the zona pectinata of the basilar membrane is enlarged, with a hyaline mass between upper and lower basilar membrane fibers. This zona pectinata hypertrophy is least at the base of the cochlea and greatest in the upper second turn, decreasing again toward the apex. Basilar membrane width increases rapidly in the first turn and then changes only slightly.Except for Liomys, all the heteromyids studied have hypertrophied Hensen's cells with long apical processes supporting and forming an elevated reticular lamina. These Hensen's cells reach their maximum size in the upper second and lower third turns; throughout they rest on inner Claudius' cells rather than the basilar membrane. Relative to naso‐occipital length the cochlear specializations are greatest in Microdipodops and least in Liomys just as is the case for middle ear modifications.The morphological data are consistent with the concept that standing wave phenomena may be important in heteromyid cochlear biomechanics. Single unit data of other workers are also consistent with this interpretation. Like middle ear morphology, inner ear morphology appears adapted to low‐frequency sensitivity–especially in Dipodomys and Microdipodops.
Embryogenesis of Xyleborus ferrugineus (Fabr.) (Coleoptera, Scolytidae). II. Developmental rates of male and female embryos
Authors: Beeman Sylvia L. , Norris Dale M. 
Published: February 2005

AbstractThe developmental rates of male and female embryos of Xyleborus ferrugineus were compared by charting for each sex the mean age for each of ten discrete morphological stages of embryogenesis from pole cell exclusion to eclosion. Male and female embryos developed synchronously from stage 1 (which begins with pole cell exclusion) through stage 4 (which ends with the completion of germ band extension and metamerization). After stage 4 and throughout the remainder of embryogenesis, the mean ages per morphological stage of male embryos were significantly greater than those for female embryos. The expected physiological consequences of a haploid genome in the male embryo as compared to a diploid condition in the female embryo are discussed as the possible basis for the persistent lag observed in male developmental rate after stage 4.
Intrinsic organization of snake medial cortex: An electron microscopic and golgi study
Authors: Ulinski Philip S. 
Published: February 2005

AbstractThe intrinsic organization of medial cortex in snakes, primarily of the genera Natrix and Boa, was studied using Golgi and electron microscopic techniques. The area has three distinct layers, each containing a characteristic population of neurons. Stellate cells comprise a relatively small population of neurons with their somata and dendrites restricted to layer 1, the most superficial layer. Their axons course horizontally in layer 1. Candelabra cells form the largest population of neurons in medial cortex. Their somata lie densely packed in layer 2 and are joined by specialized junctions. Ascending dendrites extend from the somata into layer 1. They consist of spine‐free proximal segments and spine bearing distal segments. Descending dendrites extend from the somata into the upper half of layer 3. The proximal segments bear few spines but branch into several tapered, distal segments which have a moderate covering of spines. One or two axons originate from the descending dendrites and descend through layer 3. The axons bear collaterals in the deep half of layer 3 and eventually bifurcate in the alveus. The medial branches run into the septum; the lateral branches course through other cortical areas. The axons bear frequent varicosities within medial cortex. Periventricular cells lie in the deep half of layer 3, either singly or in clusters. Their ascending dendrites extend radially into layer 1 where they branch into distal segments which resemble those of the candelabra cells. Their descending dendrites arborize horizontally in the alveus and bear a moderate covering of spines. Ependymal cells line the ventricular surface and send radial processes through the area's depth bearing lamellate processes.
Structure and carbohydrate histochemistry of the esophagus in ten teleostean species
Authors: Reifel Conrad W. , Travill Anthony A. 
Published: February 2005

AbstractThe histology and carbohydrate histochemistry of ten teleostean esophagi were compared. Structurally, the four layers of a typical vertebrate digestive tract were consistently present. The epithelium was always stratified and in all but one species (Ictalurus nebulosus) contained taste buds. Esophageal mucous cells were not the typical goblet cells seen in other vertebrates but appeared to be of six different types, pairs of which were associated with particular families. In esocids, poorly developed mucous acini and serous monogranular cells were present. In all species, the subepithelial connective tissue was not divided into definitive lamina propriae and submucosae due to the absence of muscularis mucosae. Variably present in this connective tissue region were argentophilic fibers and in esocids only, randomly dispersed striated muscle fibers. The arrangement of the muscularis was reverse to that of the general vertebrate plan. In mucous cells, three general types of epithelial mucosubstances were identified and in broad terms were recognized as sulfomucins, sialomucins and neutral mucosubstances. Morphological differences were accompanied by differences in carbohydrate localization, each esophageal epithelium containing at least two different mucosubstances. However, the mucosubstances identified in each mucous cell had a profile of characteristics different in some respects from any other. Thus teleostean esophagi appear to perform an integrated diversity of functions as reflected by their complex morphology and carbohydrate histochemistry.
Oogenesis in the Female Sterile (1)42 Mutant of Drosophila melanogaster
Authors: Rizzo William B. , King Robert C. 
Published: February 2005

AbstractThe sex‐linked mutation fs(1)42 was induced by ethyl methane sulfonate. It has no effect on either the external morphology or longevity of adult hemizygotes or homozygotes. Heterozygotes and hemizygotes are fertile, but homozygotes are sterile. Egg chamber development proceeds through stage 8, and thereafter chambers degenerate. Dying follicle cells are seen in chambers at all positions in the ovarioles. Profollicle cells also die within germaria, and clusters of sister cystocytes take longer than normal to receive their coverings of follicle cells. Egg chambers in the vitellarium contain only about 60% the normal number of follicle cells, these generally have greater lateral dimensions, and their nuclei and nucleoli are also larger than normal. The follicular envelope of mutant chambers often contains gaps through which cystocytes send cytoplasmic projections. Abnormalities seen in development of the fs(1)42 oocyte are likely to be due to its envelope of defective follicle cells.
Presence of marchi‐positive myelinoid bodies in the spinal cord white matter of some vertebrate species
Authors: Hildebrand Claes 
Published: February 2005

AbstractThe occurrence of Marchi‐positive myelinoid bodies in the ventrolateral cervical spinal cord white matter was investigated by light and electron microscopy in adult animals of the following species: cat, rabbit, guinea pig, rat, mouse, frog and perch. In addition some observations were made on human specimens. The bodies were found to be present in all the examined species, being most numerous in the rabbit and guinea pig. The lowest incidence was seen in the mouse and frog. The bodies consistently prevailed along the paranodes of large myelinated fibers and generally showed a rounded or ovoid shape. In all animals the size spectrum of the Marchi‐positive myelinoid bodies showed a peak at about 3 μ. The sizes varied from less than 1 μ to over 25 μ. The size range was widest in the perch, the ventrolateral white matter of which contained a great number of very large bodies, and most narrow in the rat. Calculations of the total myelinoid body volume per unit volume of ventrolateral white matter or myelin, showed very high values in the perch (0.03 μ3/μ3 myelin), high values in the cat, rabbit and guinea pig (0.006‐0.007 μ3/μ3 myelin) and low values in the rat, mouse and frog (0.001‐0.002 μ3/μ3 myelin). The white matter specimens from animals with a high total myelinoid body volume contained large fibers with thick myelin sheaths, which were not found in the specimens from animals with a low total myelinoid body volume.Electron‐microscopically, the picture was rather uniform. In all species examined the myelinoid bodies were composed of a lamellated shell of varying thickness that surrounded a central zone of highly electron‐dense material or an empty cavity. In most cases the bodies were linked to myelin sheaths through oligodendroglial cytoplasm. Less frequently free bodies were observed within astrocytes or microglia.The findings are interpreted in support of the view that myelinoid bodies may be regarded as an expression of the turnover of myelin material in thick myelin sheaths.
Cytoplasmic bridges within the follicular epithelium of the ovarioles of two diptera, Aedes Aegypti and Stomoxys Calcitrans
Authors: Meola S. M. , Mollenhauer H. H. , Thompson J. M. 
Published: February 2005

AbstractThe cells of the follicular epithelium of the ovarioles of the mosquito, Aedes aegypti (L.), and of the stable fly, Stomoxys calcitrans (L.), have been found to be interconnected by cytoplasmic bridges. Cytoplasmic bridges have been reported between sibling gamete cells of both male and female insects, but these bridges have not been previously reported to exist between somatic cells of insects.
An unusual cytoplasmic organelle in oocytes of Ilyanassa obsoleta
Authors: McCann‐Collier Marjorie 
Published: February 2005

AbstractAn unusual organelle in the oocytes of the marine mud snail Ilyanassa obsoleta is described and called a polymerosome, because of its several components. Polymerosomes appear at the beginning of vitellogenesis and persist, in part, through postvitellogenesis. The persistent part is similar to an organelle that has been described by other workers in the vegetal region and the polar lobe of the Ilyanassa egg.
Histophysiological studies on the corpus allatum during prepupal diapause in Monema flavescens (Lepidoptera)
Authors: Takeda Naokuni 
Published: February 2005

AbstractThe appearance of the corpus allatum, the central endocrine gland of diapause, was examined histologically in the slug moth prepupae, Monema flavescens (Lepidoptera)Before beginning of diapause, the secretory cells of the corpus allatum increase in size with the enrichment of the cytoplasm in quantity and in number of organelles, while RNA synthesis also starts. As diapause progresses, the secretory cells have many large unstained vacuoles in the cytoplasm, which were demonstrated to contain some substances of lipoidal nature. It is not clear that the substance is juvenile hormone itself or a material related to juvenile hormone. Agranular ER is the most characteristic organelle connected with mitochondria and situated around the vacuoles during diapause. Electron micrographs show that agranular ER and mitochondria have an essential role for the production of juvenile hormone.The function of the corpus allatum during diapause and the relationship between juvenile hormone and diapause are discussed.
Blood circulation in the balanomorph barnacle, Megabalanus californicus (Pilsbry)
Authors: Burnett Bryan R. 
Published: February 2005

AbstractCompared to the lepadomorph barnacles, the morphology of hemolymph circulation in the balanomorphs is poorly known. This report on Megabalanus californicus is the first detailed description of blood circulation in a balanomorph barnacle.In Megabalanus hemolymph circulates in a similar pattern to that seen in lepadomorphs. However, Megabalanus shows major differences. (1) The mantle and associated structures ( =peduncle in the lepadomorphs) shows no large sinuses and blood is directed to branchiae via well defined vessels. (2) The gut is entirely invested with vessels from the distributive system (except for the proctodaeum). (3) A large sinus in the thoracic region (thoracic sinus) has no similar structure in the lepadomorphs. (4) The prosomal sinus is reduced and positioned dorsally. (5) The rostral sinus is larger than any found in the lepadomorphs and receives a substantial amount of blood from the peripheral circulation.The smallness of the prosomal sinus in Megabalanus probably is due to lack of a contractile peduncle. In the lepadomorphs the prosomal sinus likely serves as a storage sinus for hemolymph when the peduncle is contracted.
The diversity of neurosecretory cell types in the cave tick Ornithodoros tholozani
Authors: Gabbay Shoshana , Warburg M. R. 
Published: February 2005

AbstractNeurosecretory cells are arranged in 16 NSC centers in the different regions of the brain of O. tholozani. The component cells belong to 13 different types, of which five types are paraldehyde fuchsin positive and the remaining types are negative. Three of these cell types are here described for the first time. Some of these NSC show an affinity to certain localities inside the brain. Cells comprising a neurohaemal organ were found near the exit of the esophagus.
A scanning electron microscopic study of differentiation of the digital pad in regenerating digits of the kenyan reed frog, Hyperolius viridiflavus ferniquei
Authors: Richards Christina M. , Carlson Bruce M. , Connelly Thomas G. , Rogers Sherry L. , Ashcraft Elizabeth 
Published: February 2005

AbstractNewly metamorphosed Kenyan reed frogs, Hyperolius viridiflavus ferniquei, are able to regenerate amputated digits. The terminal digital pad is also completely reformed. Differentiation of the regenerating digital pad was studied by scanning electron microscopy. External differentiation of the digital pad began late in the second postamputational week with the appearance of small patches of specialized epidermal cells on the ventral surface of the regenerating digit. The differentiation of the pad spread out radially until late in the fourth week, when its overall shape approximated that of the normal digital pad. The appearance of patches of digital pad epidermis on the ends of spike regenerates arising from the forearm was also confirmed.
The relation between size of motoneurons and their position in the cat spinal cord
Authors: Clamann H. P. , Kukulka C. G. 
Published: February 2005

AbstractExperiments were performed to test whether motoneurons in the plantaris and medial gastrocnemius muscles of the cat are arranged in the spinal cord according to their sizes. It was found that motoneurons are randomly distributed with respect to size in their motor nuclei. Evidence is also presented that motoneuron density in these pools is irregular, and that there is considerable variability of position of medial gastrocnemius and plantaris motor pools from animal to animal.