Cell border

Run the simulation for 1000 iterations. Average, over the last 200 iterations, the count of S cells in each of the five rows next to the border cells. 

Stephenson, M.B. and Hawes, M.C. (1994) Correlation of Pectin Mcthylesterase Activity in Root Caps of Pea with Root Border Cell Separation. Plant Physiol. 106 739-... 

Figure 9.7 (a) The epithelial brush border cells of the small intestine concentrate glucose from the intestinal lumen in symport with Na+ this is driven by the (Na+-K+)-ATPase located on the capillary side of the cell. The glucose is then exported by a passive uniport system. (From Voet and Voet, 2004. Reproduced with permission from John Wiley Sons., Inc.) (b) Two Na+-binding sites in the LeuT Na+-dependent pump. (From Gouax and MacKinnon, 2005. Copyright (2005) American Association for the Advancement of Science.)... 

The resorption process is facilitated by the large inner surface of the intestine, with its brush-border cells. Lipophilic molecules penetrate the plasma membrane of the mucosal cells by simple diffusion, whereas polar molecules require transporters (facilitated diffusion see p. 218). In many cases, carrier-mediated cotransport with Na"" ions can be observed. In this case, the difference in the concentration of the sodium ions (high in the intestinal lumen and low in the mucosal cells) drives the import of nutrients against a concentration gradient (secondary active transport see p. 220). Failure of carrier systems in the gastrointestinal tract can result in diseases. 

Orally administered drugs partition into the lipid bilayer in the process of diffusing across the apical and basolateral membranes of the intestinal brush border cells into the blood, as illustrated in Figure 2. About 1800 such drugs are commercially available. A small surface area of the polar parts of the drug molecule generally favors entry into the hydrophobic interior of... 

High-molecular-weight compounds in rhizodeposition are mainly represented by mucilage and ectoenzymes, which are actively released via exocytosis. Mucilage is released from hypersecretory cells, which subsequently degenerate or are sloughed-off as root border cells. 

Hawes, M.C., Brigham, L. A. Impacts of root border cells on microbial populations in the rhizosphere. Adv Plant Pathol 1992 8 119-148. 

Their growth is characterized by the sequence of proliferation, confluency, differentiation. Morphologically they reveal typical brash border cells with columnar shape and microvilli, polarization, cubble-stone morphology with flower-like clusters (Pinto et al. 1983 Hidalgo and Borchardt 1989), presence of... 

Villin is an example of a bundling protein. Villin is found in the microvilli of, for example, intestinal brush border cells (Fig. 5-30). The microvilli greatly increase the surface area of the cells, which is essential for effective absorption to take place. Each microvillus extends about 2 p.m into the lumen of the gut and is supported by 20 or so actin filaments tightly bundled by villin (and other proteins) at regular intervals. In a feature common to many actin-based networks, all the filaments in the bundle are oriented with their barbed ends in the same direction, in this case toward the tip of the microvillus where they terminate. Cross-linking of the actin filaments to the plasma membrane occurs via a second protein from the myosin-1 family (a relative of the well-known contractile protein myosin-II). This protein binds its head domain to the sides of the filaments and embeds its tail domain into the membrane. 

The worksheet displayed by the GT Calculator files by the action of the Reduce a Character command button, Figure 1.5, is shown in Figure 1.12. This worksheet takes as input the character, F, normally a reducible representation, i.e. a set of traces of the matrix representatives of the operators of the group and returns the direct sum components of this character, identified by Mulliken symbols. This input is entered in the red-bordered cells and the direct sum components are returned as numbers of Mulliken symbols in the last row of the display. 

Absorptive Cells. Absorptive cells (commonly called enterocytes or brush border cells) are the most prevalent type of cells on the tips of villi and are the most... 

B. Megaloblastic anemia is caused by a decrease in the synthesis of deoxythymidylate and the purine bases usually caused by a deficiency in either THF or cobalamin or both. This results in decreased DNA synthesis, which results in abnormally large hematopoietic cells created by perturbed cell division and DNA replication and repair. This patient exhibits signs of chronic alcoholism, which often leads to a folate deficiency. This can occur due to poor dietary intake, decreased absorption of folate due to damage of the intestinal brush border cells and resulting conjugase deficiency, and poor renal resorption of folate. 

Gap Junctions Communication between bordering cells is possible via direct contact in the form of gap junctions . Gap junctions are channels that connect two neighboring cells to allow a direct exchange of metabolites and signaling molecules between the cells. 

Fig. 206. Plots of the distribution of mossy fibers on the dorsal (caudal) surface of lobule IV in the cat. A. Fibers from the central cervical nucleus (Matsushita and Tanami, 1987). B. Fibers from the medial vestibular nucleus (Matsushita and Wang, 1987). C. Fibers from the thoracic cord (Yaginuma and Matsushita, 1987). D. Fibers from the spinal border cells (Yaginuma and Matsushita, 1986). E. Fibers from the external cuneate nucleus (Gerrits, 1985). F. Fibers from the basal pontine nuclei (Gerrits, 1985). G. Localization of AChE in the molecular layer on the dorsal surface of lobule IV. Inset sagittal section of the cerebellum of the cat.

Matsushita M, Yaginuma H (1989) Spinocerebellar projections from spinal border cells in the cat as studied by anterograde transport of wheat germ agglutinin-horseradish peroxidase. J. Comp. Neurol., 288, 19-38. 

Yaginuma H, Matsushita M (1986) The projection fields of spinal border cells in the cerebellar anterior lobe in the cat an anterograde WGA-HRP study. Brain Res.. 384, 175-179. 

The zymogen trypsinogen is cleaved to form trypsin by enteropeptidase (a protease, formerly called enterokinase) secreted by the brush-border cells of the small intestine. Trypsin catalyzes the cleavages that convert chymotrypsinogen to the active enzyme chymotrypsin, proelastase to elastase, and the procarboxypeptidases to the car-boxypeptidases. Thus, trypsin plays a central role in digestion because it both cleaves dietary proteins and activates other digestive proteases produced by the panaeas. 

Yancopoulos, G.D., Klagsbrun, M. and Folkman, J. (1998) Vasculo-genesis, angiogenesis, and growth factors ephrins enter the fray at the border. Cell 93 661-664. 

Trypsinogen, chymotrypsinogen, proelastase, and procarboxypeptidase are all synthesized as single polypeptide chains of around 25-30 kDa. The initial step in the activation is the hydrolysis of a hexapeptide from the N terminus of trypsinogen. This hydrolysis produces trypsin and is catalyzed by enteropeptidase (Fig. 14-8), an enzyme on the membranes of brash border cells of the small intestine. 

Verkhusha, V. V., Tsukita, S. and Oda, H. (1999) Actin dynamics in lamellipodia of migrating border cells in the Drosophila ovary revealed by a GFP-actin fusion protein. FEBS Lett. 445, 395-401. 

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