scholarly journals Gene–environment interactions, folate metabolism and the embryonic nervous system

2010 ◽  
Vol 2 (4) ◽  
pp. 471-480 ◽  
Author(s):  
M. Elizabeth Ross
Development ◽  
1999 ◽  
Vol 126 (4) ◽  
pp. 771-779 ◽  
Author(s):  
T. Hummel ◽  
K. Schimmelpfeng ◽  
C. Klambt

Most of the neurons of the ventral nerve cord send out long projecting axons which cross the midline. In the Drosophila central nervous system (CNS) cells of the midline give rise to neuronal and glial lineages with different functions during the establishment of the commissural pattern. Here we present evidence that beside the previously known NETRIN/FRAZZLED (DCC) signalling system an additional attractive system(s) is operating in the developing embryonic nervous system of Drosophila. Attractive cues appear to be provided by the midline neurons. We show that the glial cells present repulsive signals to the previously described ROUNDABOUT receptor in addition to a permissive contact-dependent signal helping commissural growth cones across the midline. A novel repulsive component is encoded by the karussell gene. Furthermore the midline glial cells separate anterior and posterior commissures. By genetic criteria we demonstrate that some of the genes we have identified are acting in the midline glia whereas other genes are required in the midline neurons. The results lead to a detailed model relating different cellular functions to axonal patterning at the midline.


2007 ◽  
Vol 104 (13) ◽  
pp. 5626-5631 ◽  
Author(s):  
K. Koizumi ◽  
H. Higashida ◽  
S. Yoo ◽  
M. S. Islam ◽  
A. I. Ivanov ◽  
...  

Glia ◽  
2011 ◽  
Vol 59 (9) ◽  
pp. 1264-1272 ◽  
Author(s):  
Imke Schmidt ◽  
Sigrídur Rut Franzdóttir ◽  
Gundula Edenfeld ◽  
Floriano Rodrigues ◽  
Ariane Zierau ◽  
...  

Author(s):  
Carlos A. Díaz-Balzac ◽  
José E. García-Arrarás

The nervous system of echinoderms has been studied for well over a century. Nonetheless, the information available is disparate, with in-depth descriptions for the nervous component of some groups or of particular organs while scant data is available for others. The best studied representatives to date are the nervous system of echinoid embryos and larva, and the adult holothurian nervous system. Although described sometimes inaccurately as a neural net, the echinoderm nervous system consists of well-defined neural structures. This is observed since early embryogenesis when activation of the anterior neuroectoderm gene regulatory networks initiate the formation of the embryonic nervous system. This system then undergoes expansion and differentiation to form the larval nervous system, which is centered on the ciliary bands. This “simpler” nervous system is then metamorphosed into the adult echinoderm nervous system. The adult echinoderm nervous system is composed of a central nervous system made up of a nerve ring connected to a series of radial nerve cords. Peripheral nerves extending from the radial nerve cords or nerve ring connect with the peripheral nervous system, located in other organs or effectors including the viscera, podia, body wall muscles, and connective tissue. Both the central and peripheral nervous systems are composed of complex and diverse subdivisions. These are mainly characterized by the expression of neurotransmitters, namely acetylcholine, catecholamines, histamine, amino acids, GABA, and neuropeptides. Other areas of interest include the amazing regenerative capabilities of echinoderms that have been shown to be able to regenerate their nervous system components; and the analysis of the echinoderm genome that has provided essential insights into the molecular basis of how echinoderms develop an adult pentaradial symmetry from bilaterally symmetric larvae and the role of the nervous system in this process.


1983 ◽  
Vol 33 ◽  
pp. 110
Author(s):  
Shinobu C. Fujita ◽  
Tomoaki Shirao ◽  
Kunihiko Obata

1997 ◽  
Vol 64 (1-2) ◽  
pp. 31-39 ◽  
Author(s):  
Helge Hartung ◽  
Benjamin Feldman ◽  
Heike Lovec ◽  
Francois Coulier ◽  
Daniel Birnbaum ◽  
...  

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