Although food poisoning might not seem as a critical threat, it can cause severe illness and sometimes even lead to death. The infection is mediated by pathogens which invades the host through utilizing the epithelial cells in organs (Schneeberger and Lynch, 2004). The epithelial cells are composed of tight junctions, which are located between each cell. It consists of water-proof connected proteins that act as a barrier separating the external cellular contents from the internal. Proteins such as claudin, occludin, etc play an important role in the regulation of ions and molecules traveling through the cells (Schneeberger and Lynch, 2004). Although tight junctions provide a barrier for the epithelial cells, its permeability can be jeopardizing by foreign pathogens. The purpose of this study is to
Which of the following structures is not normally found in the cytoplasm of a resting cell?
Numerous cells have little, finger-formed projections of the plasma film on their uncovered surfaces. These projections, called microvilli (solitary, microvillus), significantly increment the surface territory of the phone presented to the extracellular environment. Likewise, they cover the surfaces of cells that are effectively engrossing materials from the extracellular liquid, for example, the cells coating the stomach related tract. Microvilli have broad associations with the cytoskeleton. A center of small scale fibers hardens each microvillus and grapples it to the cytoskeleton at the terminal web.
Brennan K, Tateson R, Lewis K, Arias AM. A Functional Analysis of Notch Mutations in Drosophila. Genetics. 1997;147(1):177-188.
Epithelial-mesenchymal transition (EMT) is a cellular process that is essential for normal processes in many organisms, including embryonic development and wound healing, and is recapitulated in human disease, contributing to organ fibrosis and cancer progression (Thiery et al. 2009; Yang and Weinberg 2008). EMT describes the conversion of a cell with an epithelial phenotype to one with mesenchymal characteristics and can be a partial or complete transformation. Epithelial cells form the borders of tissues and organs, and are characterized by apical-basal polarity, contact with a basement membrane, and strong adherence to other epithelial cells through intercellular junctions including adherens junctions, tight junctions, and desmosomes. Conversely, mesenchymal cells have front-rear polarity and generally lack cell-cell contact, allowing them to be motile. During human embryonic development, EMT is essential for the formation of a variety of tissues, including mesoderm, neural crest, somites, palate, pancreas, liver, reproductive tracts, and heart valves (Thiery et al. 2009; Yang and Weinberg 2008). After development, partial EMT also contributes to wound healing (Thiery et al. 2009). However, EMT can also play a more insidious role by factoring into tumour progression.
Figure 1.b shows the ‘Lock and Key’ model where two individual substrates meet the active site where
I think the cell from NPC would look like clusters of bumps attacking the smooth Endoplasmic Reticulum
The expression of Notch1 and Notch2 in HSCs is shown to be important for their response to endothelial – derived maintenance factor.
How are medially-positioned progenitors affected by diffusible signals? The number of neurons belonging to populations found near or at the centre of the dorsoventral axis of the cord is influenced by signal levels, including Shh and BMPs. A moderate concentration of BMP signaling is needed to generate the correct number of medial interneurons. In zebrafish mutants in which a particular BMP protein is functionally reduced, there was a resulting increase in Lim1+ interneurons (medial interneurons) post-mitotically (Nguyen et al., 2000). Interestingly, further BMP reduction decreases medial interneuron counts, illustrating the fine balance of BMP levels that is needed to establish appropriate medial interneuron expression. Perturbing natural
GnT-III suppression alters Notch receptor localization- Autophagy has been shown to regulate the Notch pathway in normal physiology and disease (16). Therefore we performed immunocytochemistry to determine the localization of Notch 1 in OVCAR3 cells. Notch 1 is observed in intracellular vesicles and the nucleus in control shRNA OVCAR3 cells and does not colocalize with LAMP1 (Fig. 5A). However, in GnT-III shRNA OVCAR3 cells Notch 1 is primarily localized with the late endosome/lysosome marker LAMP1 indicating that a larger percentage of Notch 1 is in this fraction (Fig. 5A, white arrows). To further confirm these findings we treated cells with chloroquine to raise the pH of this cellular compartment and inhibit lysosomal enzymes (17). We found no effect on Notch 1 levels in control cells treated with chloroquine; while GnT-III shRNA cells show a significant increase in Notch 1 levels when lysosomal enzymes are inhibited (Fig. 5B).
The development of the cortex is a delicate balance between proliferation, differentiation and migration of neural progenitors (NPs). Throughout developmental process, various cellular mechanisms ensure that NPs are differentiating into the correct cell subtypes, migrating to their correct regions, and forming the correct cortical and sub-cortical layers. The cortex is comprised of both excitatory and inhibitory neurons, which interact within neuronal circuits to mediate cortical functions. Though both types of neurons reside in the cortex, they arise from different embryonic brain regions, and from different neural progenitors. Excitatory neurons are generated from neural progenitors residing in the ventricular zone (VZ)/subventricular
If my hypothesis is supported, the images of PKCγ-Cγ1 will show the PKCγ spread towards the edges of the cell and be less concentrated in the middle. The images of fascin-FTIC will show that the fascin has moved toward the edges of the cell along with the PKCγ. Layered images will show the overlapping of of PKCγ and fascin, suggesting a strong interaction between the two proteins. A magnified inspection of the edges of the cell will show both PKCγ and fascin have concentrated in the protrusions of the cell
In mice, this process starts around Embryonic Day 11.5 as the neural progenitor cells located in the Ventricular and Subventricular Zones (SVZ) migrate upwards to form what will later become Layers 2 through 6. Neurons are formed as these neural progenitor cells become Radial Glial Cells (RGC), a subpopulation of stem cells, and differentiate. The timing of the differentiation determines when neurons will form the lower or upper layers. When the differentiation occurs early in neurogenesis, the neurons migrate slightly to form the lower layers. In later neurogenesis, the differentiated neurons migrate past the lower layers and begin forming the upper layers. The formation of the upper layers tends to arise from differentiation of Intermediate Progenitor Cells (IPCs) rather than RGC differentiation. IPCs are formed from neural progenitor cells alongside RGCs (Kwan et al. 1538). While neurogenesis in humans may lead to differing relative sizes of the layers and SVZ, the structure of six specified layers is the same. The divisions between the layers do not occur in humans until around gestational week 9 to 11 (Deboer et al.
Mutations in genes coding for component of the Notch signaling pathway cause a disease called Alagille syndrome. Alagille syndrome (ALGS) is a multi-organ pediatric disorder. Some ALGS patients develop small multi-cystic kidney disease. The Surendran lab has developed mouse models of Notch-signaling-deficient multicystic kidney disease. Studies in the mouse models have revealed that Notch signaling “maintains the alignment of cell division in the proximal tubules during nephrogenesis and loss of Notch signaling may lead to cystic renal disease and tumorigenesis due to misoriented cell division” (Surendran, Selassie, Liapis, Krigman, Kopan, 2010). Notch Signaling occurs between neighboring cells, in which ligand expressing cell activate the
The five different cell junctions are known as tight, gap, desmosome, hemidesmosome and adherens junctions.