bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphological identification of the motor neurons innervating the dorsal longitudinal flight muscle of Drosophila melanogaster
Authors: Ikeda Kazuo , Koenig J. H. 
Published: May 2005

AbstractThe dorsal longitudinal flight muscle (DLM) of Drosophila is composed of six muscle fibers (DLM1‐6 from ventral to dorsal) and innervated by five motor neurons (MNs), DLM1‐4 being innervated singly by MN1‐4, and DLM5 and 6 being jointly innervated by MN5. This study identifies and describes the five motor neurons that innervate these six muscle fibers. Horseradish peroxidase (HRP) applied intracellularly to single identified DLM fibers resulted in the labeling of the single motor neuron innervating that muscle fiber by retrograde transsynaptic transport. This method allowed positive identification of the motor neuron innervating a particular muscle fiber, since only the innervating neuron was labeled. The axonal pathway, soma, and dendritic distribution of each labeled motor neuron was traced in the thoracic ganglion, and their relative positions were determined.The somata of MN1‐4 lie in a cluster located near the lateral surface of the thoracic ganglion at the border of the pro‐ and mesothoracic regions, ipsilateral to the muscle fibers innervated. The somata of MN1 and 2 lie side by side in a horizontal plane with MN1 in a more anterior position. Those of MN3 and 4 lie ventrally to those of MN1 and 2 in a horizontal plane with MN3 in the more anterior position. The soma of MN5 is located contralaterally to the muscle fiber it innervates, lying in the dorsal outermost layer of the thoracic ganglion next to the midline at the border of the pro‐ and mesothoracic regions. In spite of the distant contralateral location of the soma, the dendritic distribution of MN5 occurs in the same area as those of MN1‐4. From these result, these neurons can now be identified in the general ganglionic structure revealed by silver impregnation. The ontogenetic contralateral origin of MN5 and the phylogenetic origin of all five MNs are discussed.
GABA as a potential transmitter in lizard photoreceptors: Immunocytochemical and biochemical evidence
Authors: Engbretson Gustav A. , Anderson Kathy J. , Wu Jang‐Yen 
Published: May 2005

AbstractThe retina of the desert night lizard, Xantusia vigilis, was examined for immunoreactivity to antibodies against γ‐aminobutyric acid and L‐glutamate decarboxylase. At the electron microscopic level it was found that a distinct population of the photoreceptor cells was immunoreactive to both antibodies. Computer‐assisted reconstruction of serial sections positively identified the immunoreactive receptors as cones. These cones constituted 15% of the photoreceptors in the retinal sections, and they were morphologically distinct. The mean diameter of the labeled cone synaptic pedicles was 5.8 μm whereas that of the unlabeled pedicles was 7.9 μm, a statistically significant difference. L‐glutamate decarboxylase was extracted from the lizard brain, positively identified radiometrically, and shown by immuno‐diffusion to crossreact with the antibody used for localization. The authors suggest that the immunoreactive cones synthesize and accumulate γ‐aminobutyric acid. Whether or not it is used by those cones as a neurotransmitter should be tested directly.
Ultrastructure of an identified molluscan neuron in organ culture and cell culture following axotomy
Authors: Berdan R. C. , Hauser G. , Bulloch A. G. M. 
Published: May 2005

AbstractWe examined the ultrastructure of neuron 5 from the buccal ganglion of the mollusc Helisoma trivolvis after axotomy and organ culture, and after isolation of the same neuron in culture. Buccal ganglia containing axotomized neurons 5 were cultured either in host snails or in Leibovitz medium conditioned with ganglia. In addition, some neurons 5 were isolated from buccal ganglia by micro‐dissection and plated into culture. Neuron 5 and its processes were identified in both whole mounts and plastic sections of buccal ganglia after intracellular injection with Lucifer Yellow or horseradish peroxidase. Five days after axotomy of neuron 5, thick sections of buccal ganglia stained with toluidine blue revealed that densely staining basophilic bodies (Nissl bodies) within the cytoplasm had dispersed, i.e., they had undergone chromatolysis. Coincident with chromatolysis was an overall increase in diffuse basophilic staining within the cytoplasm of neuron 5 when maintained in organ culture. The dispersion of Nissl bodies viewed by light microscopy correlated with a more freely arranged rough endoplasmic reticulum and associated polysomes within neuron 5 as seen by electron microscopy. Isolated neurons 5 did not possess densely staining Nissl bodies when examined after 2 days in vitro, thus indicating that chromatolysis occurred earlier in isolated neurons. Furthermore, no increase in diffuse cytoplasmic basophilia was observed within isolated neurons 5 cultured in vitro. However, isolated neurons 5 exhibited a marked increase in the number of lipid‐like bodies (0.5–1.5 μm in diameter) that were particularly evident in scanning electron micrographs. Scanning and transmission electron micrographs revealed that the isolated neurons were free of associated glia, but non‐neuronal cells (hemocytes) would attach themselves to the somata and neurites. Glia surrounding neuron 5 within buccal ganglia exhibited a marked hypertrophy following axotomy and organ culture. Hypertrophy of glia was absent, however, if ganglia were axotomized and left within the animal or axotomized ganglia were implanted into host animals and examined 5 days later by electron microscopy. These observations indicate that, following axotomy, a molluscan neuron may exhibit different morphological features depending on its microenvironment. In addition, the hypertrophy of glia surrounding neurons in Helisoma was not associated with axotomy per se, but with organ culture.
Localization of two calcium binding proteins, calbindin (28 kD) and parvalbumin (12 kD), in the vertebrate retina
Authors: Hamano K. , Kiyama H. , Emson P. C. , Manabe R. , Nakauchi M. , Tohyama M. 
Published: May 2005

AbstractWe used immunocytochemistry to locate two calcium binding proteins, calbindin (CaB) and parvalbumin (PV), in the retina of goldfish, frog, chick, rat, guinea pig, dog, and man. The location of CaB depended on the type of dominant photoreceptor cells in birds and mammals. In cone‐dominant retinas such as those of the chick, CaB‐like immunoreactivity was found in the cones, cone bipolars, and ganglion cells. Amacrine cells 5–12 μm across were also labeled. In rod‐dominant retinas, such as those of the rat, guinea pig, and dog, horizontal cells, small amacrine cells (about 6 μm across), and cells in the ganglion cell layer were labeled. In the human retina, which has both cones and rods in abundance, cones, cone bipolars, ganglion cells, horizontal cells, and small and large amacrine cells were labeled. In the frog and goldfish, the level of CaB‐like immunoreactivity was low. In the frog, a few cones, amacrine cells, and cells in the ganglion cell layer were labeled. No immunoreactive structures were seen in the goldfish retina.PV‐like immunoreactivity was found in chicks, rats, and dogs. No such immunoreactive structures were seen in the other species. In the chick, only amacrine cells were labeled. In the rat, amacrine cells and several displaced amacrine cells were labeled. In the dog, in addition to amacrine cells and displaced amacrine cells, horizontal cells were strongly labeled. Thus, PV‐like immunoreactivity was found in those elements relating to the modulation of the main pathway of the visual transmission system.
Topographic organization of subcortical projections to the anterior thalamic nuclei in the rat
Authors: Shibata Hideshi 
Published: May 2005

AbstractSubcortical projections to the anterior thalamic nuclei were studied in the rat, with special reference to projections from the mammillary nuclei, by retrograde and anterograde transport of wheat germ agglutinin conjugated to horseradish peroxidase.The medial mammillary nucleus (MM) projects predominantly ipsilaterally to the entire anterior thalamic nuclei, whereas the lateral mammillary nucleus projects bilaterally to the anterodorsal nucleus (AD) of the anterior thalamic nuclei. A topographic relationship was recognized between the MM and the anterior thalamic nuclei. The dorsal region of the pars mediana of the MM projects to the interanteromedial nucleus (IAM), whereas the ventral region projects to the rostral part of the anteromedial nucleus (AM). The dorsal and the ventral regions of the pars medialis project to the dorsomedial part of the AM at its caudal and rostral levels, respectively. The dorsomedial region of the pars lateralis projects to the ventral AM. The ventrolateral region of the pars lateralis projects to the ventral part of the anteroventral nucleus (AV) in such a manner that rostral cells project rostrally and caudal cells project caudally. The pars basalis projects predominantly ipsilaterally to the dorsolateral AV and bilaterally to the AD. The rostrolateral region of the pars posterior projects to the lateral AV, whereas the medial and the caudal regions of the pars posterior project to the dorsomedial AV.The rostrodorsal part of the nucleus reticularis thalami was found to project to the anterior thalamic nuclei; cells located rostrally in this part project to the IAM and AM, whereas cells located caudodorsally project to the AV and AD. The laterodorsal tegmental nucleus projects predominantly ipsilaterally to the AV, especially to its dorsolateral part.The present study demonstrates that subdivisions of the subcortical structures are connected to the subnuclei of the anterior thalamic nuclei, with a clear‐cut topography arranged in the dorsoventral and the rostrocaudal dimensions. © 1992 Wiley‐Liss, Inc.
Cholinergic innervation of the human thalamus: Dual origin and differential nuclear distribution
Authors: Heckers Stephan , Geula Changiz , Mesulam Marek‐Marsel 
Published: May 2005

AbstractThe cholinergic innervation of the human thalamus was studied with antibodies against the enzyme choline acetyltransferase (ChAT) and nerve growth factor receptor (NGFr). Acetylcholinesterase histochemistry was used to delineate nuclear boundaries. All thalamic nuclei displayed ChAT‐positive axons and varicosities. Only the medial habenula contained ChAT‐positive perikarya. Some intralaminar nuclei (central medial, central lateral, and paracentral), the reticular nucleus, midline nuclei (paraventricular and reuniens), some nuclei associated with the limbic system (anterodorsal nucleus and medially situated patches in the mediodorsal nucleus) and the lateral geniculate nucleus displayed the highest density of ChAT‐positive axonal varicosities. The remaining sensory relay nuclei and the nuclei interconnected with the motor and association cortex displayed a lower level of innervation.Immunoreactivity for NGFr was observed in cholinergic neurons of the basal forebrain but not in cholinergic neurons of the upper brainstem. The contribution of basal forebrain afferents to the cholinergic innervation of the human thalamus was therefore studied with the aid of NGFr‐immunoreactive axonal staining. The anterior intralaminar nuclei, the reticular nucleus, and medially situated patches in the mediodorsal nucleus displayed a substantial number of NGFr‐positive varicose axons, presumably originating in the basal forebrain. Rare NGFr‐positive axonal profiles were also seen in many of the other thalamic nuclei.These observations suggest that thalamic nuclei affiliated with limbic structures and with the ascending reticular activating system are likely to be under particularly intense cholinergic influence. While the vast majority of thalamic cholinergic input seems to come from the upper brainstem, the intralaminar and reticular nuclei, and especially medially situated patches within the mediodorsal nucleus also appear to receive substantial cholinergic innervation from the basal forebrain. © 1992 Wiley‐Liss, Inc.
Laminar pattern of termination of the ipsilateral cortical projection from SII to SI in cats
Authors: Barbaresi Paolo , Guandalini Paola , Manzoni Tullio 
Published: May 2005

AbstractThe present light and electron microscopic experiments were carried out on the first somatic sensory area (SI) of cats to determine the laminar distribution of axon terminals from the ipsilateral second somatic sensory area (SII) and to identify the types of synapses between these terminals and the neuronal elements of SI. Phaseolus vulgaris‐leucoagglutinin (PHA‐L) was iontophoretically injected into multiple sites and at different cortical depths of the forepaw representation zone of SII. Fixed brain blocks containing the injected SII and ipsilateral SI were cut into slices and processed immunocytochemically to stain PHA‐L‐filled fibers and terminals. Light microscopic examination of SI revealed patches of anterograde labeling in the forepaw representation zone, concentrated mainly in supragranular layers. In these layers, thin immunolabeled fibers branched extensively and formed a dense plexus that was more prominent in layers II and I. Conversely, the infragranular layers contained fragments of vertically oriented thick fibers that rarely emitted axon collaterals. PHA‐L‐labeled axons had numerous swellings along their course, interpreted as boutons en passant, and stalked boutons. Of 19,661 labeled terminals (17,833 beads and 1,828 stalked boutons), 84.74% were obse in supragranular layers, with the highest concentration in layer II(33.15%) and lower in layers I (26.27%) and III (25.30%). The proportion of terminals was lower in layers IV (6.49%) and V (5.45%) and lowest in layer VI (3.32%). These counts also showed that boutons en passant were the majority (90.70%) and stalked boutons, the minority (9.30%). The ratio of these two types of presynaptic specializations was similar (9:1) in all six layers.Electron microscopic examination of the labeled regions of SI showed that both axon swellings and stalked boutons formed synapses of the asymmetric type with SI neuronal elements. The majority (85.37%) of a sample of 130 labeled terminals synapsed on SI neurons in layers I‐Ill. The identified postsynaptic profiles were dendritic spines (61.11%) or mediumsized and small dendrites (38.89%). These results are discussed in relation to those of a companion study on the laminar pattern of the projection from SI to SII of cats (P. Barbaresi, A. Minelli, and T. Manzoni, 1994, J. Comp. Neurol. 343:582–596). Based on the anatomical organization of these reciprocal connections, there seems to be no clear hierarchicalal relationship between SI and SII in cats. © 1995 Wiley‐Liss, Inc.
Age and sex do not affect the volume, cell numbers, or cell size of the suprachiasmatic nucleus of the rat: An unbiased stereological study
Authors: Madeira M. Dulce , Sousa N. , Santer R. M. , Paula‐Barbosa M. M. , Gundersen H. J. G. 
Published: May 2005

AbstractThe circadian rhythms displayed by numerous biological functions are known to be sex specific and affected by aging. It has not been settled yet whether the sex‐ and age‐related characteristics of circadian rhythms derive from changes in the anatomy of the suprachiasmatic nucleus. To shed light on these issues, we applied unbiased stereological techniques to estimate the volume of the suprachiasmatic nucleus as well as the total number of its cells and the mean volume of their somata and nuclei in progressively older groups of male and female Wistar rats (aged 1, 6, 12, 18, 24, and 30 months). The volume of the nucleus was estimated with the Cavalieri principle on serial sections. The total numbers of neurons and astrocytes were estimated by applying the optical fractionator, and the mean somatic and nuclear volumes of cells were estimated by using isotropic, uniform random sections and the nucleator method. On average, the volume of the suprachiasmatic nucleus was 0.044 mm3, and the total number of neurons and astrocytes was 17,400. Cells of the dorsomedial and ventrolateral components of the nucleus, which are morphologically different, have identical mean perikaryal and nuclear volumes, which we estimated to be 750 μm3 and 400 μm3, respectively.We further demonstrated that, at all ages analysed, the volume of the suprachiasmatic nucleus, the total cell number, and the mean somatic and nuclear volumes of its cells are affected neither by the age nor by the sex of the animal, regardless of the presence of sex‐ and age‐related variations in circadian rhythms. However, the possibility that females may display changes in the volume of the suprachiasmatic nucleus at older ages cannot be ruled out. No effect of aging was observed in the total number of neurons or in the total number of astrocytes. © 1995 Wiley‐Liss, Inc.
Kinetics of CVD of stoichiometric and Si‐excess SiC in the system MTS/H2 at medium decomposition of MTS
Authors: Josiek Andrei , Langlais Francis 
Published: May 2005

AbstractFor medium decomposition of MTS (10–90 %), at total pressures P < Pt, the growth rate depends fairly strongly on the total flow rate, but is practically independent of P. For P > Pt, the inverse relation holds. In both regions, the growth rate is residence‐time independent, and the apparent activation energy is about 200 kJ/mol. Pt increases with increasing total flow rate, increasing temperature and decreasing initial H2/MTS ratio. For P < Pt, nearly stoichiometric polycrystalline SiC is deposited whereas for P > Pt, nanocrystalline SiC with an important excess of Si grows.
Effect of prenatal heat stress at mid‐ and late gestation on the learning of mature guinea‐pigs
Authors: Lyle J. G. , Jonson K. M. , Edwards M. J. , Penny R. H. 
Published: May 2005

AbstractMature guinea‐pigs which had been heat stressed at different gestational ages along with their treated and untreated controls were tested on a black‐white serial discrimination task with 1 reversal. A significant difference resulted between animals stressed at 40‐44 days gestation and their treated controls, but only on perseverative errors on the reversal task. No differences existed between animals stressed at 56‐60 days gestation and their treated controls, nor between the various control groups.
Zebrafish R‐cadherin (Cdh4) controls visual system development and differentiation
Authors: Babb Sherry G. , Kotradi Shannon M. , Shah Bijal , Chiappini‐Williamson Christin , Bell Lauren N. , Schmeiser Glen , Chen Elbert , Liu Qin , Marrs James A. 
Published: May 2005

AbstractIn zebrafish, R‐cadherin (cadherin‐4 or Cdh4) is expressed in the retina and in retinorecipient brain regions, suggesting that Cdh4 functions during visual system development. Cdh4 function was examined during retinogenesis and retinal axon outgrowth using antisense morpholino oligonucleotides and mutant Cdh4 construct expression. In knockdowns, Cdh4 was reduced or absent, eyes were small, and retinae lacked discrete laminae. Increased cell death produced the small eye phenotype. Zn5‐, Pax6‐, and zpr‐1–positive cells were reduced or absent in knockdown retinas but, when present, were in the correct laminae. Cdh4 knockdowns had sparse or absent retinal ganglion cell axons. When present, axons projected contralaterally but lacked fine branching and failed to reach the tectum or arborize the entire tectum. Mutant Cdh4 construct expression during retinal ganglion cell differentiation reduced or ablated neurite formation. Cdh4 is necessary for neural retina survival and differentiation, and required for normal retinotectal projection formation and tectal arborization. Developmental Dynamics 233:930–945, 2005. © 2005 Wiley‐Liss, Inc.
Peptides of normal and variant cells of tobacco
Authors: Carlson Peter S. 
Published: May 2005

AbstractPolypeptides solubilized from established normal and variant cell lines of Nicotiana tabacum L cv “Wisconsin 38” have been analyzed by one‐dimensional and two‐dimensional gel electrophoresis. There was little variability observed in the polypeptide profile in an established cell line; polypeptides present in different clonal lines of cells, all derived from an initial established cell culture, were very similar, if not identical. However, a large fraction of the observed polypeptides present in cytokinin‐habituated cell lines (up to 3.8% of the total polypeptides analyzed by two‐dimensional gel electrophoresis) were different from those found in the cytokinin‐requiring cells from which they were selected. The habituated nature of the selected cell lines was demonstrated to be epigenetic; tissue cultures that were reisolated from plantlets regenerated from habituated cell lines did require cytokinin. Further observations demonstrate: (1) that epigenetic events that alter a cellular phenotype change the expression of a relatively large number of polypeptides, (2) that a single epigenetic phenotype may be the result of any one of a number of possible patterns of gene expression, and (3) that epigenetic events are not random events.
Inhibition by ammonia of intracellular cAMP accumulation in dictyostelium discoideum: Its significance for the regulation of morphogenesis
Authors: Schindler J. , Sussman M. 
Published: May 2005

AbstractTwo compounds, ammonia (NH3) and 3′5′ cyclic AMP (cAMP) act as specific morphogens in regulating the development of Dictyostelium discoideum [1–11]. A previous study [12] demonstrated that NH3 at concentrations that affect the course of morphogenesis completely inhibits the extracellular release of cAMP by aggregation competent cells incubated in shaken suspension. The present study extends this finding in two respects:

Exposure of aggregation competent cells to NH3 (supplied as ammonium carbonate) is followed within a few minutes by the complete disappearance of intracellular cAMP. Subsequent removal of NH3 is followed by a rapid, complete restoration of the level. Neither the disappearance nor the reappearance is affected by the presence of cycloheximide, an inhibitor of protein synthesis.
In a mutant strain of D discoideum, greatly increased sensitivity to NH3 as a regulator of morphogenesis is coupled with a correspondingly increased sensitivity to NH3 as an inhibitor of cAMP accumulation.
These results are consistent with a recently proposed [13, 14] model of morphogenetic regulation that is based on the supposition that NH3, by inhibiting cAMP production, restricts cAMP accumulation to specified constrained areas within the developing multicellular aggregate and thereby dictates the course of morphogenesis and cytodifferentiation.