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Marginal Region (marginal + region)
Selected AbstractsCath6, a bHLH atonal family proneural gene, negatively regulates neuronal differentiation in the retinaDEVELOPMENTAL DYNAMICS, Issue 9 2010Fumi Kubo Abstract Basic helix,loop,helix (bHLH) transcription factors play important roles in cell type specification and differentiation during the development of the nervous system. In this study, we identified a chicken homolog of Atonal 8/ath6 (Cath6) and examined its role in the developing retina. Unlike other Atonal-family proneural genes that induce neuronal differentiation, Cath6 was expressed in stem cell-like progenitor cells in the marginal region of the retina, and its overexpression inhibited neuronal differentiation. A Cath6 fused with a VP16 transactivation domain recapitulated the inhibitory effect of Cath6 on neuronal differentiation, indicating that Cath6 functions as a transcription activator. These results demonstrate that Cath6 constitutes a unique member of the Atonal-family of genes in that it acts as a negative regulator of neuronal differentiation. Developmental Dynamics 239:2492,2500, 2010. © 2010 Wiley-Liss, Inc. [source] Gap junctional coupling between progenitor cells at the retinal margin of adult goldfishDEVELOPMENTAL NEUROBIOLOGY, Issue 3 2001Fuminobu Tamalu Abstract We prepared living slice preparations of the peripheral retina of adult goldfish to examine electrical membrane properties of progenitor cells at the retinal margin. Cells were voltage-clamped near resting potential and then stepped to either hyperpolarizing or depolarizing test potentials using whole-cell voltage-clamp recordings. Electrophysiologically examined cells were morphologically identified by injecting both Lucifer Yellow (LY) and biocytin. All progenitor cells examined (n = 37) showed a large amount of passively flowing currents of either sign under suppression of the nonjunctional currents flowing through K+ and Ca2+ channels in the cell membrane. They did not exhibit any voltage-gated Na+ currents. Cells identified by LY fills were typically slender. As the difference between the test potential and the resting potential increased, 13 out of 37 cells exhibited symmetrically voltage- and time-dependent current decline on either sign at the resting potential. The symmetric current profile suggests that the current may be driven and modulated by the junctional potential difference between the clamping cell and its neighbors. The remaining 24 cells did not exhibit voltage dependency. A gap junction channel blocker, halothane, suppressed the currents. A decrease in extracellular pH reduced coupling currents and its increase enhanced them. Dopamine, cAMP, and retinoic acid did not influence coupling currents. Injection of biocytin into single progenitor cells revealed strong tracer coupling, which was restricted in the marginal region. Immature ganglion cells closely located to the retinal margin exhibited voltage-gated Na+ currents. They did not reveal apparent tracer coupling. These results demonstrate that the marginal progenitor cells couple with each other via gap junctions, and communicate biochemical molecules, which may subserve or interfere with cellular differentiation. © 2001 John Wiley & Sons, Inc. J Neurobiol 48: 204,214, 2001 [source] New red alga, Acanthopeltis longiramulosa sp. nov. (Gelidiales, Rhodophyta) from Jeju Island, KoreaPHYCOLOGICAL RESEARCH, Issue 4 2003Yongpil Lee SUMMARY A new red alga from Jeju Island, Korea is described. The alga is assigned to Acanthopeltis, Gelidiaceae by the characteristics of terete erect axes, sympodial growth, and suborbicular branchlets that are amplexi-caul at the base. Acanthopeltis longiramulosaY. Lee et Kim is characterized by a discoid holdfast with a few stolons, rhizoids arising from the apex of the branchlet, an erect terete axis diverging into a few branches, longish obpyriform to lanceolate branchlets with smooth surfaces, and tetrasporangial stichidia or sper-matangial and cystocarps appendages on the marginal region of the branchlet. A. longiramulosa is more closely related to Acanthopeltis japonica than Acanthopeltis hirsuta in terms of thallus morphology. However, A. longiramulosa is easily distinguished from A. japonica, which has suborbicular branchlets with setaceous processes on both surfaces. [source] Expression of VEGF-C and VEGF-D as Significant Markers for Assessment of Lymphangiogenesis and Lymph Node Metastasis in Non-Small Cell Lung CancerTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 5 2010Yukuan Feng Abstract Vascular endothelial growth factor (VEGF)-C and VEGF-D induce lymphangiogenesis through activation of VEGF receptor 3 (VEGFR-3) and have been implicated in tumor spread to the lymphatic system. Lymph node dissemination critically determines clinical outcome and therapeutic options of patients with non-small cell lung cancer (NSCLC). However, the relationship of VEGF-C, VEGF-D, and lymph node metastasis in cancers, including NSCLC, is still controversial. To evaluate the relationship between lymphangiogenesis and lymph node metastasis, the expression of VEGF-C and VEGF-D in NSCLC tumors were detected by immunohistochemistry and quantitative real-time polymerase chain reaction (QRT-PCR). QRT-PCR revealed that in marginal region VEGF-C and VEGF-D mRNA was significantly higher than in tumor center, and VEGF-D mRNA was also higher than that in peritumoral lung tissue. Immunohistochemically, we observed the same heterogeneous expression of VEGF-C and VEGF-D proteins. The group with high expression of VEGF-C and VEGF-D in marginal region had a higher incidence of lymph node metastasis compared with the group with low expression. Furthermore, the group with high expression of VEGF-D in marginal region had a higher incidence of lymphatic invasion. The group with high peritumoral lymphatic vessel density (LVD) had higher expression of VEGF-C and VEGF-D mRNA compared with the group with low peritumoral LVD. Our studies suggested that the expression of VEGF-C and VEGF-D at invasive edge was significantly associated with lymph node metastasis or lymphatic invasion in patients with NSCLC and may be involved in regulation of lymphangiogenesis and lymph node metastasis in NSCLC. Anat Rec, 2010. © 2010 Wiley-Liss, Inc. [source] | ||||||||||