bluuebunny/crossref_metadata_2025_split huggingface dataset:
A quantitative electron microscope analysis of peripheral nerve in the urodele amphibian in relation to limb regenerative capacity
Authors: Egar Margaret , Singer Marcus 
Published: February 2005

AbstractAn approximate 1:1 ratio of myelinated to unmyelinated fibers was established in counts from electron micrograph montages in nerves of the newt, Triturus (Notophthalmus) viridescens. The number of myelinated fibers correspond to the number counted with the light microscope after osmium fixation. Light microscope counts of silver impregnated sections yielded a value slightly higher suggesting that, except for bundles of unmyelinated fibers, the silver technique revealed mainly myelinated fibers. The results were used to reassess previous quantitative studies on the relation between number of nerve fibers and the control which nerves exert on regeneration. For a truer estimate of the number of axons affecting regeneration, fiber values previously reported should now be doubled to include the large number of unmyelinated fibers. However, calculations show that the unmyelinated fibers contribute less than 3% of the total neuroplasm in the peripheral nerve.Finally, counts made of Schwann cells and fibroblasts show that the latter are few in number.
Variations and developmental abnormalities in the sexual apparatus of the adult axolotl (Siredon mexicanum)
Authors: Brunst V. V. 
Published: February 2005

AbstractThe sexual apparatus was studied in 100 adult axolotls (Siredon mexicanum) for 13 different spawnings. The ages of the animals varied between two and six years. Additional material from Indiana University was also studied. Altogether there were 55 female and 52 male adult axolotls represented. The purpose of the study was to investigate the limits of the variations occurring in normal axolotls and to compare the incidences of variations and developmental abnormalities in adult animals of both sexes at various ages and belonging to different strains.Among the 13 spawnings examined, five strains were completely normal in 100% of the animals, but the remaining eight strains all included abnormal animals. The incidence of abnormal animals in some of these latter strains was 40% or even 50%. Since all of the animals were under the same conditions, the variability and the occurrence of developmental abnormalities most likely depended upon hereditary factors. Among 55 females, only seven (12.7%) were abnormal; only four of these had developmental abnormalities, and only one was hermaphrodite. Among 45 males from the author's axolotl colony, 16 (28%) were abnormal. Of these latter, six had no sex cells or very few; this variation must be regarded as a developmental abnormality. All of these malformations resulted from major degeneration processes and abnormal morphogenesis.Arrested development was also observed in many males. Spermatozoa were completely absent from the testes of eight animals. In the additional material from Indiana University (testes from 7 males), there was also one completely abnormal testis with major degeneration processes and complete absence of sex cells. It is evident that variability and the incidence of developmental abnormalities in the sexual apparatus in adult axolotls of some strains are very great.
Fine structure of the noctuid moth ear. I. The transducer area and connections to the tympanic membrane in Feltia subgothica haworth
Authors: Ghiradella Helen 
Published: February 2005

AbstractThe sensillum of the ear of Feltia subgothica contains two ciliated receptor cells, the A cells. The cilium of each is enclosed within a well developed scolops consisting of a cap, a set of scolopalial rods and a collar, an unusual structure contained within the dendrite. The tip of the cilium is inserted in a channel in the scolopalial cap.The cap is linked to the tympanic membrane by a series of three structures: a cap cell, a microtubular shaft and a microfibrillar plug. The two latter structures are heavily reinforced by cytoskeletal elements and the microfibrillar plug is actually continuous with the tympanic membrane. These three structures transmit the vibration of the tympanic membrane to the scolops.The simplicity and accessibility of the ear suggests that it might be a good system in which to investigate cellular events associated with transduction of sound in these receptors.
Spermatogenesis in bombyx mori. I. The canal system joining sister spermatocytes
Authors: King Robert C. , Akai Hiromu 
Published: February 2005

AbstractAn electron microscopic investigation was made of the origin and morphology of the canal system that connects sister spermatocytes of larval Bombyx mori. Canal formation results from incomplete cleavages during the mitoses which immediately precede meiosis. We suggest the lip which surrounds each canal is derived from the contractile ring which is prevented from constricting completely by interaction with the midbody. Cells were found with as many as four canals which demonstrates that canal rims can persist through a number of mitotic cycles. Speculations are advanced as to the significance of these canals in restricting gonocytes from unlimited divisions.
Striated visceral muscle of Drosophila melanogaster
Authors: Goldstein Margaret Ann , Burdette Walter J. 
Published: February 2005

AbstractStriated visceral muscle cells are scattered singly or in small groups at the base of the intestinal cells of the mid‐gut of Drosophila melanogaster larvae. Fibers less than 1 μ in diameter, designated as small, contain a single myofibril, few, if any, dyads and few mitochondria. Fibers of somewhat larger diameter contain dyads and more mitochondria. Both types of fiber have a perforate Z band which appears as discontinuous bodies in longitudinal sections and as a perforate sheet of dense rims and clear perforations in transverse sections. The Z rims contain filaments, 30 to 50 Å, oriented in the transverse direction. The number and arrangement of myofilaments and the ultrastructure of the Z band are consistent with the function of these muscles.
The number of centrioles in insect sperm: A study in two kinds of differentiating silkworm spermatids
Authors: Friedländer M. , Wahrman J. 
Published: February 2005

AbstractThe typical eupyrene and atypical apyrene cycles of sperm differentiation in Bombyx mori were studied, with special attention to centriole number and behavior. Contrary to other reports, there is always only one centriole in the differentiating and in the mature sperm, thus confirming our previous findings that insect sperm has one centriole at the base of the flagellum, in contrast to two centrioles found in many other groups of animals. This numerical difference is discussed in an evolutionary context.
A gross study of the compartmentalized stomach of two new‐world camelids, the llama and guanaco
Authors: Vallenas A. , Cummings J. F. , Munnell J. F. 
Published: February 2005

AbstractThe llama and guanaco stomach consisted of three compartments. A transverse pillar divided the large, first compartment into cranial and caudal sacs. Both sacs contained recessed glandular saccules. The saccules in the caudal sac were everted during the gastric contraction cycle. The non‐recessed surfaces of this compartment were covered by stratified squamous epithelium.The first compartment communicated on the right with a smaller, reniform second compartment. Except on the lesser curvature, this compartment contained deep cells which were lined by a papillated glandular mucosa.The ventricular groove, defined by a single muscular lip, coursed along the cranial sac of the first compartment, over the lesser curvature of the second compartment, and terminated at the tubular passage to the third compartment.The initial four‐fifths of the elongate third compartment contained mucigenous glands like those found in the saccules and cells of the first and second compartment Proper gastric glands and pyloric glands were confined to the terminal one‐fifth of the third compartment.Attempts to homologize the compartments of the camelid stomach with those of the Pecora or so‐called advanced ruminants were unsuccessful. The results of this study and concurrent physiologic investigations indicated that the processes of ruminant digestion can operate within wide anatomic boundaries, and that the camelid stomach with its extensive glandular mucosa is adapted for greater digestive efficiency than the advanced ruminant stomach.
An electron microscopic study of the corpus cardiacum of adult Drosophila melanogaster and its afferent nerves
Authors: Aggarwal Surinder K. , King Robert C. 
Published: February 2005

AbstractThe left and right afferent nerves to the corpus cardiacum contain approximately 50 and 90 axons, respectively, when they enter the gland. Both bifurcate within the gland, so that four nerves leave the corpus cardiacum. These, however, contain a total of 90 axons. Of the 50 axons unaccounted for 30 are believed to terminate in the corpus cardiacum and 20 in the corpus allatum. The corpus cardiacum contains 12 intrinsic neurosecretory cells which are disposed laterally with respect to the extrinsic axons. Many of these contain neurosecretory spheres and presumably originate in the brain. The intrinsic corpus cardiacum cells also contain neurosecretory granules, and they produce short cytoplasmic processes which interdigitate with the extrinsic axons.
Ultrastructure of the epidermis in the ice worm, Mesenchytraeus solifugus
Authors: Goodman Daniel , Parrish Wayne B. 
Published: February 2005

AbstractThe ice worm is adapted for life at O°C. A survey of the ultrastructure of the cuticle, epidermal epithelium and basement membrane does not reveal any features which self‐evidently correlate with such metabolic specialization; instead, these tissues are much like those of the earthworm and some freshwater oligochaetes. The cuticular fibers are unstriated. Epithelial cells aresuggested as the source of cuticular material. Epithelial microvilli penetrate the cuticle. There is an array of membrane bound bodies on the cuticle surface. The basement membrane fibers are transversely striated and are oriented in crossed lamellae. The junctional complex is represented by azonula adhaerens and septate desmosome.
Reproductive systems of the north indian langur (Presbytis entellus entellus Dufresne)
Authors: David G. F. X. , Ramaswami L. S. 
Published: February 2005

AbstractThe gross anatomy and histology of the gonads and accessory sex organs are described for male and female Presbytis e. entellus. The langur differs from other catarrhine monkeys in certain specialised characters. The “sexual skin” is not comparable to the true sexual skin of the Cercopithecinae which exhibits cyclical change during the various phases of reproduction; it is nevertheless fully developed in the adult male and serves as one of the secondary sexual characters.Certain aspects of the reproductive system strikingly resemble those of man. The combined testicular weight (0.07% body weight) is similar to the human (0.08%), and the male has ampullary glands. The cervical canal is straight like that of a baboon or man. The corpus luteum (except in the lactating female) is a hollow glandular structure. Extensive hemorrhage which always accompanies ovulation in the langur, does not appear to be a common phenomenon in any other catarrhine for which ovulation and the development of corpus luteum have been studied. The hemorrhagic remains are retained for a long time in the ovulated follicle.The ovary is characteristically large and averages 0.74 gm without corpus luteum and 1.57 gm with corpus luteum, a feature never reported in any other catarrhine monkeys. The pre‐ovulatory follicle may attain a size of 14 × 14 mm.
The ultrastructure of developing wings in the giant silkmoth, Hyalophora cecropia. II. Scale‐forming and socket‐forming cells
Authors: Greenstein Masha Etkin 
Published: February 2005

AbstractIn wings of the giant silkmoth, Hyalophora cecropia, scale‐forming and socket‐forming cells are first observed on day four of pharate adult development. Scale‐forming cells appear synthetically active when they are first observed, for their basal region is filled with huge stacks of polyribosome‐studed lamellate endoplasmic reticulum, numerous Golgi complexes containing secretory vesicles and many elongated mitochondria. During later development, some of these organelles diminish in number. Neck and scale regions are predominantly filled with longitudinally oriented microtubules and microfibril bundles, suggesting that their function is one of transport rather than synthesis. The scales originate as finger‐like projections of the cell body. They subsequently elongate, flatten out and deposit a cuticle which has a surface differing somewhat from that in other lepidopterans. It consists of longitudinal ridges (1.8‐2.4 μ apart), transverse ribs (0.6‐1.0 μ apart) and microribs (0.10‐0.13 μ apart).Socket‐forming cells produce a socket around the neck region of each scale‐forming cell. The socket differentiates into several morphologically distinct regions: an apical fibrillar region, a ribosomal region, a mitochondrial‐microtubular region and a basal fibrillar region. The absence of polyribosome‐studded lamellae of endoplasmic reticulum and Golgi complexes suggests that its primary function is not biosynthesis but support and protection of the scale.
Necleolar reorganization in epithelial cells of the jejunum of the rat
Authors: Adamstone F. B. , Taylor A. B. 
Published: February 2005

AbstractLight microscope studies were made on nucleoli of jejunal epithelial cells of normal rats fixed in OsO4, glutaraldehyde, F.A.A. and HgCl2 and stained with basic fuchsin–alkaline methylene blue. Nucleolar reorganization is extensive and clearly resembles the phenomenon of nucleolar segregation. Polymorphous nucleoli of undifferentiated crypt cells show intermingled constituents and stain purple whereas similar nucleoli of definitive absorptive cells show two homogeneous components–A, stained red and B, stained blue. Cytochemical studies indicate that component A is largely protein and acidophilic and component B is largely nucleic acids and basophilic. These nucleoli become compacted, each forming an amphinucleolus with the two components at opposite poles. Further changes occur along the villi and the components generally separate to form a condensed plasmosome and a diffuse karysome. Extruded cells show nucleolar fragmentation.Electron micrographs of OsO4 material were used in preparation of wax models. These, along with electron micrographs of glutaraldehyde material stained with uranyl acetate and lead citrate, clearly illustrate and duplicate light microscope findings and strongly resemble nucleolar segregation produced by antimetabolites.Cells of the villi with reorganized nucleoli do not undergo mitosis whereas undifferentiated crypt cells do so. Furthermore, nucleolar reorganization is correlated with aging since it begins in crypt cells and culminates in senescent cells at the tips of the villi.A review is given of the extensive evidence showing that, in the intestine certain functional changes occur similar to those demonstrated in experimental nucleolar segregation. These include gradually changing patterns of DNA, RNA and protein synthesis as well as enzyme activity. The accompany and probably result from nucleolar reorganization.
The structure of the ventricle of Elliptio complanatus, a fresh‐water lamellibranch
Authors: Rutherford John G. 
Published: February 2005

AbstractThe morphology of the ventricle of the fresh‐water lamellibranch, Elliptio complanatus, was investigated. Contrary to the condition reported previously in Tritogonia verrucosa, the two atria in Elliptio communicate with the ventricular lumen through separate openings, each guarded by an atrio‐ventricular valve. Fixation of ventricle for electron microscopy with 2.5% buffered glutaraldehyde did not appear to shrink the tissue, in spite of the low blood osmolarity to which the muscle is adapted. Ventricle tissue is composed of smooth muscle fibers, containing a central nucleus, glycogen, mitochondria, paramyosin, dense bodies and “attachment plaques,” much like the ventricle of the salt‐water clam, Venus (Mercenaria) mercenaria.
A cytological study of the ovary of Rhodnius prolixus. I. The ontogeny of the follicular epithelium
Authors: Huebner Erwin , Anderson Everett 
Published: February 2005

AbstractThe relatively undifferentiated cells comprising the prefollicular epithelium of the fourth and fifth instar of the reduvid bug Rhodninus prolixus are flattened and contain the regularly occurring organelles, lipid droplets, and aggregates of glycogen‐like particles. These cells transform into the adult prefollicular tissue.During vitellogenesis there is a gradual shortening of the cells of the follicular epithelium and an increase in the size of the intercellular space between them and between follicle cells and oocyte. The follicle cells are binucleate, contain numerous microtubules, rough endoplasmic reticulum, many free and aggregate ribosomes, and Golgi complexes. They are associated with each other by gap junctions. Only the follicle cells on the lateral aspects of the oocyte exhibit the development of large extracellular spaces while those at the apical end, that produces the cap, remain tall and closely apposed to each other during vitellogenesis. The normal morphology of the follicle cells over various areas of the oocyte suggests that shape and/or volume changes of these cell may be important in regulating the access of yolk proteins to the colemma.Subsequent to vitellogenesis the follicle cells become cuboidal and once again become closely apposed to each other. They contain much rough endoplasmic reticulum and produce the secondary coat.
Ultrastructural observations on oogenesis in Drosophila
Authors: Mahowald Anthony P. 
Published: February 2005

AbstractThe ultrastructure of the follicle cells and oocyte periplasm is described during the stages of oogenesis immediately prior to, during, and immediately subsequent to, vitellogenesis. A number of features have not been described previously in Drosophila. Some yolk appears prior to pinocytosis of blood proteins. However, most of the protein yolk forms while the periplasm is filled with micropinocytotic invaginations and tubules derived from the oolemma. These tubules retain the internal layer of material characteristic of coated vesicles and are found to fuse with yolk spheres. No accumulation of electron‐dense material in the endoplasmic reticulum or Golgi of the oocyte is found. Both trypan blue and ferritin are accumulated by the oocyte.The follicle cells have an elaborate endoplasmic reticulum during the period of maximum yolk accumulation. Adjacent cells are joined at their base by a zonula adhaerens, forming a band around the cells, and by plaques of gap junctions. Gap junctions are also present between nurse cells and follicle cells. During chorion formation, septate junctions also appear between follicle cells, adjacent to the zonula adhaerens.
Formed elements of the blood of the fresh water mussel, Lamellidens corrianus
Authors: Narain Arun Shanker 
Published: February 2005

AbstractThe formed elements of the blood of L. corrianus are comprised exclusively of amoebocytes, whose total number is approximately 758 per cubic mm of blood. The blood cells are of three types, viz. acidophils, large basophils and small basophils, which are respectively 26.32%, 60.20% and 13.48% of the total blood cell population. The cytoplasm of the acidophils is filled with large acidophilic granules, while that of the basophils contains fine basophilic granules. Acidophils are the largest (7.6 μ × 6.7 μ), large basophils are smaller (6.5 μ × 4.9 μ), and small basophils are the smallest (4.1 μ × 3.8 μ). The nucleus occupies a very small volume of the cell (approx. 1/9th) in acidophils, a larger volume (approx. 1/4th) in large basophils, and a major volume (approx. 3/4th) in small basophils. The blood cells show amoeboid movement, which is brought about by means of broad lamellate pseudopodia. Large basophils move very slowly, acidophils move faster, and small basophils move quite fast. Fine bristle‐like filipodia help the blood cells in getting entangled to form clumps. Filipodia are more abundant in large basophils and acidophils which pertake more actively in clumping than small basophils which rarely possess filipodia. Clumping is a reversible process which is promoted by mechanical agitation of blood.
Morphogenesis of intestinal villi. I. Scanning electron microscopy of the duodenal epithelium of the developing chick embryo
Authors: Grey Robert D. 
Published: February 2005

AbstractDevelopment of villi in the duodenum of the chick was studied in stages ranging from 11 days of incubation to one week after hatching. Formation of definitive villi is preceded by development of a set of previllous ridges that run lengthwise along the duodenum. The first set of 16 previllous ridges (Set I) is complete by about 13 days of incubation; all ridges in the set are fairly uniform and proceed through their subsequent development in synchrony. Previllous ridges in Set I fold into a highly regular zigzag pattern between 14 and 16 days of incubation. Definitive villi develop from Set I ridges beginning at about 17 days when populations of distinct cells appear on the crests of the ridges between angles in the zigzag folds. Cells in these populations lack the rounded appearance of cells seen in earlier stages; their apical surfaces are densely covered with microvilli. A second set of villi (Set II) develops at about 16 days of incubation when about 16 rows of tongue‐like flaps erupt between the previllous ridges of Set I. At hatching, Set II villi are still smaller than villi of Set I; this distinction disappears by about the fourth day after hatching. The significance of the morphological changes in epithelial cells is discussed in terms of several hypotheses bearing on the mechanisms of villus formation.
Origin of mono‐ and binucleate cells with heterochromatic chromosomes in the malpighian tubules of the european elm scale, Gossyparia spuria (Coccoidea: Homoptera)
Authors: Nur Uzi 
Published: February 2005

AbstractMales of the European elm scale, Gossyparia spuria (Erioccoccidae) have two Malphigian tubules, each made up of mononucleate and binucleate cells. Both types of cells may contain heterochromatic (H) chromosomes which form an H body. The cells with H bodies (H cells) usually appeared singly anywhere along the tubule. However, when two or more H cells were present they tended to be closer to each other than would be expected by chance. The possible origin of this tendency is discussed. Following squashing, the nuclei of the binucleate cells were much larger than those of most other somatic cells, suggesting that they were highly endopolyploid. However, the H bodies of the cells of the tubules were of about the same size as those of the other cells. These observations suggested that the H chromosomes of the binucleate cells did not replicate while the euchromatic chromosomes of these cells replicated several times. The great majority of the nuclei of the H cells contained a single H body per nucleus. An analysis of the number of H bodies in binucleate cells indicated that when two H bodies were present in the same nucleus they usually did not fuse. Thus, they were believed also not to fuse in the mononucleate cells. Since almost all the mononucleate H cells had only a single H body (rather than 2) it was concluded that they did not originate from binucleate cells by nuclear fusion.