bluuebunny/crossref_metadata_2025_split huggingface dataset:
Actin‐based phagosome motility
Authors: Zhang Fangliang , Southwick Frederick S. , Purich Daniel L. 
Published: September 2002

AbstractDespite abundant evidence of actin's involvement at the particle internalization stage of phagocytosis, little is known about whether phagosomes undergo the same type of actin‐based motility as observed with endocytic vesicles or such intracellular pathogens as Listeria and Shigella. By employing video microscopy to follow the fate of latex bead‐containing phagosomes within the cytoplasm of bone marrow macrophages, we have made the novel observation of actin‐based phagosome motility. Immunofluorescence microscopy confirmed that phagosomes containing IgG‐opsonized, bovine serum albumin (or BSA) ‐coated or uncoated latex beads all formed actin‐rich rocket tails that persisted only during a brief, 1–2 min period of actin‐based motility. Average speeds of actin‐based phagosome motility were 0.13 ± 0.06 μm/s for IgG‐coated beads, 0.14 ± 0.04 μm/s for BSA‐coated beads, and 0.11± 0.03 μm/s for uncoated beads. Moreover, the speeds and motile‐phase duration of each type of phagosome were comparable to the behavior of pinosomes [Merrifield et al., 1999: Nat. Cell Biol. 1:72–74.]. Determination of optimal conditions for observing and analyzing actin‐based phagosome motility should facilitate future investigations of phagocytosis and phagosome maturation. Cell Motil. Cytoskeleton 53:81–88, 2002. © 2002 Wiley‐Liss, Inc.
A tissue‐specific exon of myosin Va is responsible for selective cargo binding in melanocytes
Authors: Au Josephine Sui‐Yan , Huang Jian‐Dong 
Published: September 2002

AbstractClass V myosins are molecular motors used for intracellular transportation and organelle tethering. The mouse Myosin Va (MyoVa) is encoded by the dilute locus, which is alternatively spliced to generate several tissue specific isoforms. The tail of MyoVa is the putative cargo‐binding domain. To determine the functions of different isoforms of MyoVa and the minimal cargo‐binding region, we tagged various isoforms and different portions of the mouse MyoVa tail with a green fluorescent protein and examined their intracellular localizations in the mouse melan‐a cells. We found that the amino acid sequence encoded by an alternatively spliced exon, exon F, is necessary for the selective binding of MyoVa to melanosome. The MyoVa isoforms lacking this amino acid sequence are not targeted to the melanosomes, but localized to the perinuclear region instead. These findings suggested that MyoVa is able to bind to more than one types of cargos, with the selectivities determined by alternative spliced sequences. Cell Motil. Cytoskeleton 53:89–102, 2002. © 2002 Wiley‐Liss, Inc.
Laminin‐1 increases motility, path‐searching, and process dynamism of rat and mouse Muller glial cells in vitro: Implication of relationship between cell behavior and formation of retinal morphology
Authors: Méhes Előd , Czirók András , Hegedüs Balázs , Vicsek Tamás , Jancsik Veronika 
Published: September 2002

AbstractSpatial correlation was observed between the localization of laminin‐1 at the inner limiting membrane (ILM) and extensive Muller glial process arborization in the same area, as demonstrated by immunolabeling of Muller glial processes and laminin‐1 in rat retinae in situ. To test if this spatial correlation is due to a functional relationship, we investigated the impact of laminin‐1 on the motility of cultured primary rat and mouse retinal Muller glial cells by statistical analysis of computer‐controlled videomicroscopic time‐lapse images. We demonstrate that laminin‐1 increases motility and path‐searching activity of Muller cells in vitro and it also enhances the cells' process formation/withdrawal dynamism. The increase in path‐searching activity and cell process dynamism indicates that there is a functional relationship between laminin‐1 and Muller glial cells presumably involving signaling towards the cytoskeleton. We hypothesize that laminin‐1 is involved in process arborization of Muller cells at the vitread border of the retina resulting in the formation of the functional barrier made up of Muller glial endfeet. Cell Motil. Cytoskeleton 53:203–213, 2002. © 2002 Wiley‐Liss, Inc.
Arachidonic acid signaling to the cytoskeleton: The role of cyclooxygenase and cyclic AMP‐dependent protein kinase in actin bundling
Authors: Glenn Honor L. , Jacobson Bruce S. 
Published: September 2002

AbstractCell adhesion to the extracellular matrix via integrins is a primary regulatory mechanism for numerous aspects of normal cellular function. However, disruption of this interaction can result in pathology. For example, one characteristic of transformed cells is loss of adhesion dependence for viability. Adhesion also is a necessary step in tumor metastasis. It has been shown previously, in HeLa cells, that cell attachment to a gelatin‐coated substrate results in the release of arachidonic acid, which is metabolized by lipoxygenase. A subsequent cascade of lipid second messengers activates protein kinase C, which triggers actin polymerization leading to cell spreading. We now demonstrate by inhibitor studies and biochemical analysis, a parallel branch of arachidonic acid signaling that reorganizes the actin cytoskeleton into small bundles. This branch of the pathway is initiated by cyclooxygenase, which generates prostaglandins and causes the downstream activation of cyclic AMP‐dependent protein kinase. This work elucidates a system of interacting signals in which arachidonic acid functions at a branch point in cytoskeletal signaling. The lipoxygenase branch provides polymerized actin; these actin filaments act as a substrate for the cylooxygenase branch to generate actin bundles. Cell Motil. Cytoskeleton 53:239–250, 2002. © 2002 Wiley‐Liss, Inc.
Correlation between CGRP immunoreactivity and firing activity in cat abducens motoneurons
Authors: González‐Forero David , De La Cruz Rosa R. , Delgado‐García José María , Alvarez Francisco J. , Pastor Angel M. 
Published: September 2002

AbstractA relationship between motoneuron activity and calcitonin gene‐related peptide (CGRP) expression was previously suggested based on indirect inferences. We show here a positive correlation between CGRP immunoreactivity and firing activity in an experimental model that used tetanus neurotoxin (TeNT) to alter basal firing levels. A low dose (0.5 ng/kg) of TeNT injected in the lateral rectus muscle raised the basal firing rate of ipsilateral abducens motoneurons, estimated as the firing rate at straight‐ahead gaze (F0); the firing rate returned to control values after 2 weeks. In contrast, a high dose (5 ng/kg) of TeNT decreased basal firing, which recovered slowly over a 7‐week period. Expression of CGRP immunoreactivity by abducens motoneurons, preferentially related to βCGRP gene expression, was analyzed during these periods of altered firing activity. The number of CGRP‐immunofluorescent abducens motoneurons increased to ∼120% by 7 days after low‐dose TeNT, to include all available motoneurons in the nucleus. In addition, the average CGRP immunofluorescence optical density inside motoneurons almost doubled after 4 days and returned toward control values in the following 2 weeks. In contrast, a high‐dose injection of TeNT reduced the number of CGRP‐immunofluorescent motoneurons to 5.4% of control 7 days post injection, and the number returned to 77.6% after 42 days. CGRP immunofluorescence intensity inside motoneurons was also reduced. Regression analysis of F0 values with either the number of CGRP‐immunolabeled motoneurons, their average immunofluorescence intensity, or both factors combined resulted in positive correlations with regression coefficients of 0.87 or higher. Therefore, CGRP expression and firing activity in abducens motoneurons are positively correlated. J. Comp. Neurol. 451:201–212, 2002. © 2002 Wiley‐Liss, Inc.
Development and distribution of the peptidergic system in larval and adult Patiriella: Comparison of sea star bilateral and radial nervous systems
Authors: Byrne Maria , Cisternas Paula 
Published: September 2002

AbstractDevelopment of the larval peptidergic system in the sea star Patiriella regularis and structure of the adult nervous system in Patiriella species were documented in an immunofluorescence investigation using antisera to the sea star neuropeptide GFNSALMFamide 1 (S1) and confocal microscopy. P. regularis has planktotrophic development through bipinnaria and brachiolaria larvae. In early bipinnaria, two groups of immunoreactive cells appeared on either side of the anterior region and proliferated to form a pair of dorsolateral ganglia. The ganglia gave rise to fine varicose fibres that innervated the preoral and adoral ciliated bands. Peptidergic cells also innervated the postoral ciliated band, and a nerve tract connected the pre‐ and postoral bands. Fully developed bipinnaria had a well‐developed peptidergic system, the organisation of which reflected the bilateral larval body plan. As the brachiolar attachment complex differentiated at the anterior end, the ganglia became positioned on either side of the anterior projection, from which they innervated the complex. It is suggested, based on the distribution of S1‐like immunoreactivity in association with ciliary and attachment structures, that the peptidergic system functions in modulation of feeding, swimming, and settlement. The larval peptidergic system degenerates as the larval body is resorbed during metamorphosis. In adults, S1‐like immunoreactivity was intense in the axonal region of the ectoneural nervous system and in hyponeural perikarya. Immunoreactive cells in the neuroepithelium connected with the surface and may be sensory. Examination of immunoreactivity in several Patiriella species attests to the highly conserved organisation of the peptidergic system in adult asteroids. J. Comp. Neurol. 451:101–114, 2002. © 2002 Wiley‐Liss, Inc.
Genetic influences on secondary degeneration and wound healing following spinal cord injury in various strains of mice
Authors: Inman Denise , Guth Lloyd , Steward Oswald 
Published: September 2002

AbstractVarious inbred strains of mice exhibit dramatic differences in sensitivity to excitotoxic cell death induced by systemic injections of kainic acid (KA). The present study evaluates whether the same strains are also differentially sensitive to secondary degeneration after spinal cord injury, in which excitotoxic cell death is thought to play a pathogenic role. Spinal cord crush injuries were produced at T9 in two inbred strains that are resistant to KA‐induced excitotoxic cell death (C57Bl/6 and Balb/c) and four strains that are sensitive (CD‐1, FVB/N, 129T2 Sv/EMS, and C57Bl/10). The spinal cord was prepared for light microscopy at intervals from 1 to 56 days postinjury, and the area of damaged tissue (termed lesion size) and amount of cavitation were determined by quantitative image analysis. Lesion size increased between 1 and 7 days in all strains and then decreased steadily in a wound‐healing process that occurs uniquely in mice. The extent of cavitation also gradually decreased from 7 to 56 days in all strains. Although lesion area and cavitation decreased in all strains, there were significant differences in lesion size and cavitation across strains. Specifically, lesion areas in the KA‐sensitive strains FVB/N, 129T2 Sv/EMS, and CD‐1 were significantly larger at 56 days postinjury than in the KA‐resistant strains C57Bl/6 and Balb/c. We conclude that the genetic differences that confer resistance and sensitivity to KA‐induced neurotoxicity also modify the secondary degenerative processes that occur after spinal cord injury, so that resistance to excitotoxic injury leads to smaller overall lesions and a more effective wound‐healing response. J. Comp. Neurol. 451:225–235, 2002. © 2002 Wiley‐Liss, Inc.
Differential expression of calretinin and metabotropic glutamate receptor mGluR1α defines subsets of unipolar brush cells in mouse cerebellum
Authors: Nunzi Maria‐Grazia , Shigemoto Ryuichi , Mugnaini Enrico 
Published: September 2002

AbstractThe unipolar brush cell (UBC) is a type of glutamatergic interneuron in the granular layer of the cerebellum. The UBC brush and a single mossy fiber (MF) terminal contact each other within a cerebellar glomerulus, forming a giant synapse. Many UBCs receive input from extrinsic MFs, whereas others are innervated by intrinsic mossy terminals formed by the axons of other UBCs. In all mammalian species so far examined, the vestibulocerebellum is enriched of UBCs that are strongly immunoreactive for the calcium binding protein calretinin (CR) in both the somatodendritic and axonal compartment. UBCs have postsynaptic ionotropic glutamate receptors and extrasynaptic metabotropic glutamate receptors that immunocytochemically highlight their somatodendritic compartment and brush, respectively. In this study on the mouse cerebellum, we present evidence that immunoreactivities to CR and mGluR1α define two distinct UBC subsets with partly overlapping distributions in lobule X (the nodulus). In sections double‐labeled for CR and mGluR1α, the patterns of distributions of CR+/mGluR1α− UBCs and CR−/mGluR1α+ UBCs differed along the mediolateral and dorsoventral axes of the folium. Moreover, mGluR1α+ UBCs outnumbered CR+ UBCs. Both UBC subsets were mGluR2/3, GluR2/3, and NMDAR1 immunoreactive. The different distribution patterns of the two UBC subsets within lobule X suggest that expression of CR or mGluR1α by UBCs may be afferent‐specific and related to the terminal fields of different vestibular MF afferents. J. Comp. Neurol. 451:189–199, 2002. © 2002 Wiley‐Liss, Inc.
Role of Emx2 in the development of the reciprocal connectivity between cortex and thalamus
Authors: López‐Bendito Guillermina , Chan Chun‐Hung , Mallamaci Antonello , Parnavelas John , Molnár Zoltán 
Published: September 2002

AbstractEmx2 knockout mice appear to show a shift in the areal identity in the cerebral cortex of Emx2 knockout mice, which is matched with altered distribution of thalamocortical projections (Bishop et al. [2000] Science 288:344–3349; Mallamaci et al. [2000] Nat Neurosci. 3:679–686). We have examined the early establishment of these projections to understand how the altered Emx2 expression results in changes in their cortical targeting. We used carbocyanine dye tracing to visualize thalamocortical and corticofugal projections as well as immunohistochemistry for L1 and TAG‐1, respective markers of the two axonal systems, in wild‐type, heterozygote, and null mutant for Emx2 at embryonic (E) ages ranging from E13.5 to E18.5. These tracing studies demonstrated that, in Emx2 knockout mice, a large proportion of early thalamocortical projections were misrouted at the border between the diencephalon and telencephalon. This abnormality was associated with displaced connectivity of the internal capsule cells at the diencephalic–telencephalic junction. Interestingly, most of the aberrant thalamic projections compensated for the ventral entry to the telencephalon and still ascended to the cortex. Although this early targeting abnormality is associated with the altered Emx2 expression pattern in the cortex, it most probably occurs independently from it, and is related to earlier guidance defects at the diencephalic–telencephalic boundary. These defects might result in the altered and delayed arrival of thalamic projections to the cortex and, thus, contribute to the shifted thalamocortical matching previously observed in the Emx2 knockout mice. J. Comp. Neurol. 451:153–169, 2002. © 2002 Wiley‐Liss, Inc.
Acoustic trauma induces reemergence of the growth‐ and plasticity‐associated protein GAP‐43 in the rat auditory brainstem
Authors: Michler Steffen A. , Illing Robert‐Benjamin 
Published: September 2002

AbstractWe explored the consequences of unilateral acoustic trauma to intracochlear and central nervous system structures in rats. An acoustic trauma, induced by applying click stimuli of 130 dB (sound pressure level; SPL) for 30 minutes, resulted in an instant and permanent threshold shift of 95.92 ± 1.08 dB (SEM) in the affected ear. We observed, as a consequence, a structural deterioration of the organ of Corti. Deprivation‐dependent changes of neurons of the auditory brainstem were determined using antibodies against neurofilament and the growth‐associated protein GAP‐43 and compared with those following cochleotomy, studied earlier. By 231 days posttrauma, spiral ganglion cell bodies and their processes were almost entirely lost from all cochlear regions with destroyed organ of Corti. In the lateral superior olive (LSO) ipsilateral to the trauma, cell bodies of lateral olivocochlear neurons turned transiently GAP‐43 positive within the first 1.5 years posttrauma. The time course of emergence and disappearance of this population of neurons was similar to that found after cochleotomy. Additionally, after noise trauma, principal cells in contralateral LSO and in medial superior olive (MSO) on both sides of the brainstem developed an expression of GAP‐43 that began 3 and 16 days posttrauma, respectively, and lasted for at least 1 year. Such cells were rarely observed after cochleotomy. An unequivocal rise in GAP‐43 immunoreactivity was also found in the neuropil of the inferior colliculus and the ventral cochlear nucleus, both preferentially on the acoustically damaged side. We conclude that the degree and specific cause of sudden unilateral deafness entail specific patterns of plasticity responses in the auditory brainstem, possibly to prevent the neural network dedicated to locate sounds in the environment from delivering erroneous signals centralward. J. Comp. Neurol. 451:250–266, 2002. © 2002 Wiley‐Liss, Inc.
ATP‐binding cassette transporter ABCA2 (ABC2) expression in the developing spinal cord and PNS during myelination
Authors: Zhou Cheng‐Ji , Inagaki Nobuya , Pleasure Samuel J. , Zhao Li‐Xia , Kikuyama Sakae , Shioda Seiji 
Published: September 2002

AbstractWe examined developmental characteristics of the ATP‐binding cassette transporter ABCA2 (or ABC2) ‐expressing cells in rat spinal cord and peripheral nerves. In adult spinal cord, ABCA2 immunoreactivity was detected in lysosome‐like organelles of mature oligodendrocyte cell bodies, and a single specific band was detected by Western blot analysis. In postnatal developing spinal cord, ABCA2 immunolabeling was first detected in a small number of cells restricted to the ventral marginal area and the dorsal funiculus at birth (P0). ABCA2‐positive cells were co‐immunolabeled by O4, a marker for late progenitor and immature oligodendrocytes. At the same time, myelin basic protein was apparent in the same restricted regions. The number of ABCA2 and O4 co‐immunolabeled cells increased quickly in both dorsal and ventral regions from P2 and reached a peak at P8. After transient expression from P0 to P8, O4 labeling in white matter tracts decreased and disappeared. In contrast, ABCA2‐positive oligodendrocytes persisted in gray and white matter throughout the spinal cord into adulthood. These data suggest a role for the ABCA2 transporter in maturation of oligodendrocyte lineage cells and the onset of myelination in the central nervous system. In addition, ABCA2 immunoreactivity was detected in the ciliated region of the ependyma in the central canal from early postnatal development. ABCA2 immunoreactivity was also detected in the Schwann cell lineage in developing spinal nerves and in adult trigeminal and sciatic nerves. ABCA2 was also expressed in numerous undetermined cells distributed in para‐nerve connective tissues and nerve sheaths throughout early postnatal development. These data indicate multiple levels of involvement for ABCA2 in nervous system development especially with strong evidence for a role in myelination. J. Comp. Neurol. 451:334–345, 2002. © 2002 Wiley‐Liss, Inc.
Expression of Vema in the developing mouse spinal cord and optic chiasm
Authors: Runko Erik , Kaprielian Zaven 
Published: September 2002

AbstractA critical phase of nervous system development is the formation of connections between axons and their synaptic targets. Intermediate targets play important roles in axon pathfinding by supplying growing axons with long‐ and short‐ range guidance cues at decision points along their trajectory. We recently identified Vema as a novel membrane‐associated protein that is expressed at the ventral midline of the developing vertebrate central nervous system (CNS). We report that Vema is expressed in the floor plate, an intermediate target for pathfinding commissural axons located at the ventral midline of the developing mouse spinal cord. Interestingly, Vema expression overlaps with the position of an unique population of neurons situated at the midline of the ventral diencephalon and that function as intermediate targets for pathfinding retinal ganglion cell axons. The distribution of Vema in the developing spinal cord and optic chiasm resembles the expression patterns of a variety of molecules known to play important roles in axon guidance, including Robo2, Neuropilin2, and SSEA. The expression of Vema at two key choice points for pathfinding axons suggests an important role for this protein in regulating axon guidance at the midline of the developing mouse central nervous system. J. Comp. Neurol. 451:289–299, 2002. © 2002 Wiley‐Liss, Inc.
Calcium‐binding proteins map the postnatal development of rat vestibular nuclei and their vestibular and cerebellar projections
Authors: Puyal Julien , Devau Gina , Venteo Stephanie , Sans Nathalie , Raymond Jacqueline 
Published: September 2002

AbstractWe investigated whether three calcium‐binding proteins, calretinin, parvalbumin, and calbindin, could identify specific aspects of the postnatal development of the rat lateral (LVN) and medial (MVN) vestibular nuclei and their vestibular and cerebellar connections. Calretinin levels in the vestibular nuclei, increased significantly between birth and postnatal day (P) 45. In situ hybridization and immunocytochemical staining showed that calretinin‐immunoreactive neurons were mostly located in the parvocellular MVN at birth and that somatic and dendritic growth occurred between birth and P14. During the first week, parvalbumin‐immunoreactive fibers and endings were confined to specific areas, i.e., the ventral LVN and magnocellular MVN, and identified exclusively the maturation of the vestibular afferents. Calbindin was located within the dorsal LVN and the parvocellular MVN and identified the first arrival of the corticocerebellar afferents. From the second week, in addition to labeling vestibular afferents in their specific target areas, parvalbumin was also found colocalized with calbindin in mature Purkinje cell afferents. Thus, the specific spatiotemporal distribution of parvalbumin and calbindin could correspond to two successive phases of synaptic remodeling involving integration of the vestibular sensory messages and their cerebellar control. On the basis of the sequence of distribution patterns of these proteins during the development of the vestibular nuclei, calretinin is an effective marker for neuronal development of the parvocellular MVN, parvalbumin is a specific marker identifying maturation of the vestibular afferents and endings, and calbindin is a marker of the first appearance and development of Purkinje cell afferents. J. Comp. Neurol. 451:374–391, 2002. © 2002 Wiley‐Liss, Inc.