bluuebunny/crossref_metadata_2025_split huggingface dataset:
Terminal degeneration in the mediodorsal cerebral cortex of the lizard Agama agama: Light and electron microscopy
Authors: Wouterlood F. G. , Alones V. E. , Elprana D. , Lohman A. H. M. 
Published: February 2005

AbstractThe degeneration of axon terminals in the small‐celled part of the mediodorsal cortex (sMDC) of the lizard Agama agama has been studied after lesions in the dorsal cortex at various survival periods. The Fink‐Heimer stain was used to map and demonstrate terminal degeneration with the light and electron microscope. Electron microscopy was used to identify and describe degenerating boutons ultrastructurally. One sham‐operated and three unoperated animals served as controls. Between 6 and 21 days postsurgically, degenerating terminals can be seen through 80% of the superficial plexiform layer, the zone adjacent to the cellular layer remaining free of degeneration. Swelling of dendrites in the outer part of the superficial plexiform layer and increased numbers of vacuolar invaginations, both present at short (24 hr–6 days; peak at 48–54 hr) survival periods, can be regarded as reaction to the surgical trauma. Degeneration of axon terminals takes three forms, all of the electron‐dense type: gray boutons, degenerating bouton‐dendritic spine complexes surrounded or engulfed by glia, and degeneration debris inside glial processes. Several forms of terminal degeneration occur concomitantly at any short (3–12 days) survival time. At longer survival times (15–21 days) only debris is present. From 6 days on, considerable numbers of degenerating structures are present, but the majority of degenerating boutons and debris are associated with reactive glia rather than with dendrites. From these observations it is concluded that in this lizard application of the combined degeneration‐Golgi‐EM technique would probably lead to little success. Electron microscopy of Fink‐Heimer‐stained sections suggests that degenerating bouton‐dendritic spine complexes and degeneration debris accumulate silver particles, whereas gray boutons do not.
Cerebellar afferents to paramedian lobule from the trigeminal complex in Tupaia glis: A horseradish peroxidase (HRP) study
Authors: Patrick G. W. , Haines D. E. 
Published: February 2005

AbstractProjections from the trigeminal complex to paramedian lobule (PML) were studied in the tree shrew (Tupaia glis) by means of retrograde transport of horseradish peroxidase (HRP). Neurons which project to both dorsal and ventral folia of PML are located primarily in those areas of the trigeminal nuclear complex interpreted as nucleus interpolaris (Vi) and caudal areas of the nucleus oralis (Vo). The majority of HRP‐labeled neurons lie in ventral and ventrolateral regions of Vi/Vo. No HRP‐reactive cells are present in the principal (Vp), mesencephalic, or motor nuclei nor in nucleus caudalis or rostral portions of oralis. The majority of trigeminocerebellar (TC) cells are found in ipsilateral Vi; however, sparse numbers of labeled somata are present in this subnucleus on the contralateral side. Within Vi/Vo, small fusiform and medium‐ and large‐sized multipolar neurons contain HRP‐reaction product. Large multipolar cells are found primarily in ventrolateral portions of Vi/Vo, while medium and small neurons are scattered throughout the ventral half of the nucleus. Small‐sized neurons are also present dorsally within Vi/Vo. Axons of labeled TC cells course laterally through the spinal trigeminal tract, enter medial aspects of the restiform body, and arch dorsally into the cerebellum.
The early embryonic development of the primitive moth, Neomicropteryx nipponensis lssiki (lepidoptera, micropterygidae)
Authors: Kobayashi Yukimasa , Ando Hiroshi 
Published: February 2005

AbstractThis paper describes the early embryonic development of Neomicropteryx nipponensis from oviposition to the formation of the inner layer. Newly laid eggs are covered with many hygroscopic, gelatinous masses. The chorion is composed of a porous, spongy exochorion of variable thickness and of a thin endochorion. The eggs have a very thin periplasm and contain large amounts of yolk made of proteid and fatty yolk droplets. The processes of maturation division, fertilization, and cleavage are similar to those commonly found in lepidopteran eggs. The blastoderm of Neomicropteryx is very thin in comparison with that of other lepidopteran eggs. The small circular germ disk is formed on the ventral egg surface. It then invaginates deeply into the yolk to form a sac‐shaped germ rudiment. The formation of the germ rudiment and of the embryonic membranes resembles that of swift moths, Endoclita (suborder Monotrysia) and of the caddisfly, Stenopsyche (Trichoptera), but differs from that of ditrysian Lepidoptera. As in other lepidopteran insects, the formation of the inner layer begins after completion of the germ band, which has a bilobed protocephalon and a slender protocorm. Unlike the situation in most lepidopteran eggs, yolk segmentation does not occur in N. nipponensis. During formation of the germ band, hydropyle cells are formed in the dorso‐posterior region of the serosa; these are here reported for the first time in the eggs of holometabolan insects.
Abnormal differentiation of selected nuclear centers in the brain of a duck embryo associated with partial duplication of the primitive streak
Authors: Narayanan C. H. , Narayanan Y. 
Published: February 2005

AbstractIn a control set of duck embryos, and abnormal duck embryo of 16 days incubation was found which had two beaks as the only outward sign of duplication. The beaks were of equal size, each with upper and lower bills. Billclapping movements were absent. The embryo had two normal eyes placed one on either side of the head, and the rest of the body was normal in external appearance. Sections through the head revealed further duplication of the fore‐, mid‐, and hindbrain divisions. The medial half of each of the embryonic brain divisions, however, was greatly reduced. Two additional optic primordia were also noticed in sections, each of which was reduced to a mass of tissue representing a lens and a much‐folded pigment epithelium. The orbital tissues associated with the rudimentary eyes were greatly disorganized. Abnormal differentiation associated with duplication of the brain divisions was determined by cell counts in selected nuclear centers. Cell numbers in each case appeared to be remarkably proportional to the size of the innervation field. Our data, based on cell counts in the nuclear centers chosen for this study in the abnormal embryo and normal control embryos of the same age, are consistent with the hypothesis that cell survival in related parts of the nervous system may be regulated by their peripheral field of innervation.
Ultrastrucuture of the fat body of the reproductive pair in higher termites
Authors: Han Sun Heat , Bordereau Christian 
Published: February 2005

AbstractThe fine structure of the fat body of the higher termite king and queen has been studied both in species with (Macrotermes bellicosus, M. subhyalinus) and without (Cubitermes fungifaber) tracheal rosettes. There is a very pronounced sexual dimorphism. The adipocytes of the queen are highly specialized for protein synthesis and secretion; they store only a small quantity of reserves. The adipocytes of the king are not specialized in protein synthesis, but accumulate large amounts of reserve substances. The previously proposed different functions of the termite queen's fat body are discussed; it appears to be mainly concerned with vitellogenesis.
The sensory systems and feeding behavior of leafhoppers. I. The aster leafhopper, Macrosteles fascifrons stål (homoptera, cicadellidae)
Authors: Backus Elaine A. , McLean Donald L. 
Published: February 2005

AbstractThe ultrastructure of the sensilla, and other structures, within the stylets and precibarium of Macrosteles fascifrons were examined by transmission and scanning electron microscopy. Precibarium is a new term, defined here, for the canal that precedes the cibarium inside the leafhopper head. Within the precibarium are found 20 chemosensilla and a previously undescribed structure, the precibarial valve. Twelve mechanosensilla, three in each stylet, are found within the maxillary and mandibular stylets. The relationship between all of these structures and feeding by the insect is detailed in a feeding mechanism hypothesis. It is concluded that leafhoppers (and probably all homopterans) utilize the precibarial chemosensilla alone for gustatory discrimination, the stylet sensilla for proprioception, and the precibarial valve for regulation of fluid uptake and compartmentalization of the sensilla.
Development of the crayfish retina: A light and electron microscopic study
Authors: Hafner G. S. , Tokarski T. , Hammond‐Soltis G. 
Published: February 2005

AbstractThe development of the crayfish retina was examined in embryos and first, second and third instars with both and light and electron microscope. Light microscopic observations indicate that differentiation begins at the posterior portion of the optic disc and progresses in an anterior direction. Development of screening pigment, dioptric elements, and rhabdoms all parallel this posterior to anterior gradient in the retina. Tracer studies in early embryos reveal that the retina is separated from the proximal neuropil regions by a distinct vascular space. This observation suggests that the source of new cells for the retina may not be the more proximal cell proliferation zone as previously indicated. It is proposed that mitotic activity within the retina and/or differentiation of cells from the anterior surface layer of the eye may be sources for addition of new cells to the retina. Proto‐ommatidial clusters of seven retinula cells occur very early at the posterior region of the embryonic retina. Initially the receptor cells extend throughout the entire thickness of the retina, but later they withdraw from beneath the cornea to occupy only the proximal portion of the retina. Microvilli of the rhabdom arise from the centrally opposed membranes of the retinula cells in each cell cluster. Each new microvillus contains a core of fine filaments which extend out into the cytoplasm at its base. As development of the microvilli continues, the core filaments appear to be lost or altered, but the cytoplasmic bundles at the base of the microvilli persist.
Pattern development in palleal buds of botryllid ascidians: Relation between parent and its buds in their body axes
Authors: Kawamura Kazuo , Watanabe Hiroshi 
Published: February 2005

AbstractIn order to determine how the zooid pattern (normal or reversed bilateral asymmetry) is transmitted through asexual reproduction in botryllid ascidians, the axial relationship between a zooid and its palleal buds was observed in Symplegmo reptans, Metandrocarpa uedai, Polyandrocarpa misakiensis, and P. stolonifera. The bud axes developed in harmony with the parent axes, with both normal and reversed body patterns, so that (1) when buds are given off from the right (left) side of the parent, their distal side becomes the right (left) in the future zooids (coincidence of the anteroposterior axis), (2) the free surface of the developing buds, like the parent, becomes dorsal (the coincidence of dorsoventral axis), and (3) the heart (gut loop), which is an organ representing the bilateral asymmetry, arises on the distal side of the developing buds, when the buds are derived from the side where the parent heart (gut loop) was situated (coincidence of the transverse axis). This shows that the bud develops as if it knew the position on the parent lateral wall from which it has arisen, a phenomenon referred to as the parental lateral effect.
Homology and causes
Authors: Van Valen Leigh M. 
Published: February 2005

AbstractHomology is resemblance caused by a continuity of information. In biology it is a unified developmental phenomenon. Homologies among and within individuals intergrade in several ways, so historical homology cannot be separated sharply from repetitive homology. Nevertheless, the consequences of historical and repetitive homologies can be mutually contradictory. A detailed discussion of the rise and fall of the “premolar‐analogy” theory of homologies of mammalian molar‐tooth cusps exemplifies such a contradiction. All other hypotheses of historical homology which are based on repetitive homology, such as the foliar theory of the flower considered phyletically, are suspect.
Sorbic acid‐induced differences in the ultrastructural development of oocytes in the microbially ectosymbiotic female of Xyleborus ferrugineus (fabr.) (coleoptera, scolytidae)
Authors: Chu H. M. , Norris D. M. , Rao K. D. P. 
Published: February 2005

AbstractThe ovaries of the beetle Xyleborus ferrugineus reared on standard sawdust diet with an without 0.08% sorbic acid added were examined for differences in ultrastructural development of the oocytes. Indications of vigorous yolk deposition are an extensive rough‐surfaced endoplasmic reticulum (RER), numerous electron‐dense secretory vesicles and a prominent nucleus in associated follice cells, and extremely electron‐opaque material in the interfollicular cell spaces and the perioocytic area. After 6 days of feeding without added sorbic acid, a mature terminal oocyte is present in one of the two ovaries. This terminal oocyte at this mature stage contains yolk spheres and lipid bodies. However, the most mature oocyte in beetles reared on the standard sawdust diet to which 0.08% sorbic acid was added remained at a previtellogenic stage after 6 days of feeding. Titers of ecdysone in 6‐day‐old adult females reared on standard sawdust without and with 0.08% sorbic acid added were 534.64 ± 20.93 S.D. pg/mg and 39.94 ± 14.71 S.D. pg/mg body weight, respectively.
Comparative study of hemocytes and associated cells of some medically important dipterans
Authors: Kaaya Godwin P. , Ratcliffe Norman A. 
Published: February 2005

AbstractThe aim of this work is to study, characterize, and compare different morphological types of hemocytes of Glossina austeni, G. morsitans, Calliphora erythrocephala, Stomoxys calcitrans, Lucilia sericata, Aedes aegypti, and Culex quinquefasciatus. This information is intended to provide a basis for future studies of the cellular defense mechanisms of these dipterans.Seven morphological types of hemocytes were identified by phase‐contrast optics: prohemocytes, plasmatocytes, thrombocytoids, granulocytes, adipohemocytes, oenocytoids, and spindle cells of various sizes. Adipohemocytes are difficult to distinguish from both fat body cells and granulocytes. All seven cell types are not present in every species. For example, thrombocytoids and spindle cells were not found in A. aegypti or C. quinquefasciatus, and oenocytoids were observed only in A. aegypti, C. quinquefasciatus, and in C. erythrocephala.In addition to the hemocytes, fat body cells and nephrocytes are also freely present in the hemolymph of some species but may have gained access to the blood during the bleeding process.With electron microscopy and with thick plastic sections of G. austeni hemolymph, only nephrocytes, plasmatocytes, granulocytes, and spindle cells were identified wth any certainty, and the large spindle cells are morphologically very different from those found in the other dipterans. They are rigid cells supported by microtubules running throughout their entire length. These hemocytes are present in large numbers only in newly emerged flies, they are absent in larvae and young pupae, and are rare in old adults. Their disappearance from the hemolymph of newly emerged Glossiua appears to be a result of phagocytosis by the plasmatocytes.
The body surface of Branchiobdella pentodonta whit. (annelida, oligochaeta) examined by scanning microscopy
Authors: Farnesi Rosalba M. , Marinelli Marinella , Tei Simonetta , Vagnetti Daniela 
Published: February 2005

AbstractThe body of Branchiobdella pentodonta is uniformly covered with cuticular microvilli and abounds in sensory receptors. Muscle attachments are clearly visible both on the prostomium and trunk (11 segments). The mouth opening, oriented dorsally with respect to the adhesive sucker disk, possesses papillae with apical notches.On all trunk segments except the last three, which form the posterior sucker, mucous gland pores are evident. The nephridia open on the 3rd and 8th segments. On the more turgid sexual segments (5th, 6th, 7th) the spermathecal, atrial, and oviductal openings are seen. The 6th and 7th also contain the clitellum gland pores.The posterior sucker is delimited by a thick ring and the adhesive disk, and like the anterior disk is completely covered with the gland complex pores. The anal opening is on the 9th segment dorsal to the sucker. Based on these studies, we believe that the family Branchiobdellidae should be removed from the Oligochaeta and raised in rank to form a separate group.
Cell movements in a living mammalian tissue: Long‐term observation of individual cells in wounded corneal endothelia of cats
Authors: Honda H. , Ogita Y. , Higuchi S. , Kani K. 
Published: February 2005

AbstractAlthough the cells in tissues are known to be motile under special conditions (e.g., during tissue turnover or wound healing), there are not many reports that polygonal cells covering an area without leaving any gaps are also capable of movement. In the present study, cell movements (cell shifting and rearrangement) in a living mammalian eye tissue were documented by identifying and locating individual cells over intervals as long as 100 days. Cat corneal endothelium, a monolayered cell sheet, was wounded by removing a small number (about 180) of endothelial cells from the internal lining of the cornea. Healing of the wounded tissue was observed with a wide‐view specular microscope applied to the outer surface of the cornea, enabling us to identify individual cells for as long as two to three months.Cells surrounding the wound underwent areal enlargement, elongated toward the wound, and shifted to cover the wound surface. During days 4–7, cells became rearranged by changing neighbors in such a way that they retained their enlarged size but recovered their non‐elongated, original shape. This pattern of cell rearrangement was interpreted by a computer simulation which assumed that cells shorten their boundary length while maintaining contacts with contiguous cells. After day 7, the enlarged cells adjacent to the wounded area gradually contracted and pulled surrounding cells toward the wounded area. These movements were followed by a temporary halt in cell shifting, then by a recovery of shifting and cell elongation. These movements are interpreted as a result of the contractility of endothelial cell microfilaments.
Seasonal changes in the pituitary gland of the feral hawaiian mongoose (Herpestes auropunctatus)
Authors: Nelson Marita L. , Inao Jan 
Published: February 2005

AbstractThe Hawaiian mongoose (Herpestes auropunctatus) is a seasonally breeding mammal whose pituitary gland resembles that of other Viverridae. Certain features, such as a prominent pars tuberalis interna and a double‐layered pars intermedia forming a cup for the neurohypophysis, are unique.With the light microscope, five different cell types can be recognized in the pars distalis after staining with periodic acid‐Schiff (PAS)‐orange G. Two types of acidophils are seen, a small yellow‐staining cell and a large angular orange cell. Two basophilic cells are also seen, one with fine PAS‐positive cytoplasmic granules and the other with coarse PAS‐positive granules in the cytoplasm. The last cell type seen is the chromophobe. Differential cell counts indicated an altered distribution of chromophils in the ventral pars distalis of the female mongoose with changing season and reproductive status, but the most striking change was a decreased percentage of basophils in the pars distalis during the nonbreeding season.
Novel surface specialization on a sea anemone egg: “Spires” of actin‐filled microvilli
Authors: Schroeder Thomas E. 
Published: February 2005

AbstractThe ultrastructure of the “spiny” surface of Tealia crassicornis eggs is examined in detail by scanning and transmission electron microscopy in order to understand its function. Long microvilli are clustered together in spiral aggregates of 50–75 microvilli called “spires.” There are about 15,000 spires per egg. Dense bundles of microfilaments making up the cores of these microvilli are shown to be composed of actin by staining with the fluorescent dye nitrobenzoxadiazole (NBD)‐phallacidin. It is postulated that the bundles of actin and the spires of microvilli are stiff and provide reinforcement to the egg surface. Such postulated properties would provide physical protection for these large eggs which, unlike the eggs of most invertebrates, appear to lack all extracellular investing coats.
Fiber composition of the superior rectus extraocular muscle of the rhesus macaque
Authors: Pachter Bruce R. 
Published: February 2005

AbstractThe fiber composition of the superior rectus extraocular muscle of adult rhesus monkeys (Macaca mulatta) was examined in serial sections by light and electron microscopy as well as morphometry. Analyses allowed separation of singly versus multiply innervated fibers, and disclosed the morphology of these fibers and their topographical distribution within the muscle. Six morphologically distinct fiber types were found. The global layer of the muscle contains three singly innervated fibers (SIFs) and one multiply innervated fiber (MIF). The overlying orbital surface layer contains one SIF and one MIF, both showing morphological variation along their lenght. The MIFs of the orbital surface layer had not only multiple, relatively superficial endings along their length, but also endplatelike junctions in which the axonal terminals lie within synaptic clefts. These endplatelike junctions were confined to that region of the MIFs that had a morphology typical of “twitch” fibers; away from this region these MIFs had a morphology characteristic of “tonic” fibers. In contrast, the global MIFs showed constant morphology, and did not exhibit endplatelike endings.
The leukocytic organ of the megascolecid earthworm, Amynthas diffringens (annelida, oligochaeta)
Authors: Friedman Marc M. , Weiss Leon 
Published: February 2005

AbstractLeukocytic organs of Amynthas diffringens are aggregations of leukocytes contained within a smooth muscle and stromal cell framework suspended in the coelom. Elongate processes of stromal cells subdivide each organ into numerous cell‐filled compartments and are perforated by 130‐nm pores that may permit the exchange of humoral substances between compartments, or between the organ and the surrounding coelomic fluid.We divide leukocytes within the organs into four morphotypes. Phagocytic leukocytes have many lysosomelike vesicles and may possess phagosomes. Mature types I, II, and III granulocytic leukocytes share certain features but are readily distinguished by cell shape and by the size, shape, and electron density of the cytoplasmic inclusions. Immature as well as mature phagocytes and granulocytes occur within these organs, suggesting that they are sites of leukocyte maturation and storage. Concentrations of leukocytes within the organs result in extensive cell to cell contact, especially within islets and tightly packed cords. Phagocytosis of cell debris occurs throughout the organs.Immature stages of the four morphotypes are difficult to distinguish even at high magnification, raising the possibility that they may originate from a common precursor. Our inability to observe mitoses or to detect lymphocytelike stem cells suggests that immature leukocytes migrate to the organs via coelomic fluid from as yet unidentified primary sites of production.