Sunday, February 16, 2020

Discuss O-linked oligosaccharide decoration of proteins in the Essay

Discuss O-linked oligosaccharide decoration of proteins in the production of mucus and its implications in mucus-producing adeno - Essay Example These areas in the glycoprotein are aptly called mucin-like domains. Mucin-related proteins can either be membrane-bound, in which case it is enclosing the cell, or secreted to form the extracellular matrix (Tabak, 2010). In the epithelium, such as those on the surface of gastrointestinal wall, O-glyvans attached to epithelial cell membrane-bound mucin and its related proteins, mostly Muc2, constitute what is commonly called mucus. Mucin glycoproteins are made in enormous amounts by a specialized epithelial cell called the goblet cell. Physiologically, this cell is important in producing the inner mucus layer to replace the outer mucus layer used for bacterial clearance. To produce mucus, Muc2 should first be produced and secreted. They are prepared in the Golgi apparatus, in which the proteins are labeled for transport to the surface (Johansson, 2012). They can be compactly stored in large, regulated secretory mucin granules that can be found on the apical cytoplasm of goblet cells (Perez-Vilar, 2007) 2. Importance of mucus Mucus acts as a barrier from injurious elements to which the gut surface is commonly exposed to, such as bacteria and mechanical forces. Microorganisms are trapped by the outer mucus layer for transport and excretion. ... Defect in mucus production occurs from lack of Muc2 production, Muc2 mutation, or inhibition of glucosyltransferases. Without mucus, bacteria attaches to the epithelium, increases intestinal permeability, and raises risk for colitis (Kim and Ho, 2010). Aside from the gastrointestinal systems, mucus also has a protective function in the respiratory, urogenital, ophalmologic, and auditory systems. Deregulation of its production or composition is implicated in chronic airway diseases, such as chronic obstructive pulmonary disease, asthma, and cystic fibrosis (Perez-Vilar, 2007). In cystic fibrosis, the alkalization due to the defective intracellular chloride channel caused defects in pH-sensitive glucosyltransferases. The abnormal glycoproteins produced by these defective enzymes also provide receptors for Pseudomonas (Al-Awqati, Barasch, and Landry, 1992). 3. Role in cell signaling The less common O-fucose glycans are attached by O-fucosyltransderase 1 and elongated by ? 1,3N-acetylglu cosaminyltransferases to epidermal growth factor-like (EGF) repeats of Notch protein. EGF repeats are approximately 40-amino acid-long cysteine-rich motifs, including a conserved six cysteine span that forms three conserved disulfide bonds. The sugar moiety modulates protein-protein interactions and downstream signaling. Notch is a membrane-bound signaling receptor important in differentiation. Elongation of O-fucose by Fringe limits Notch activation to the dorsal and ventral boundary, since it limits the binding of Notch with its ligands. Fringe defects result to segmentation and somitogenesis defects in mice. Similar to EGF repeats, Thrombospondin tupe 1 repeats (TSR) are made up of six conserved cysteines and three

Sunday, February 2, 2020

Compare the relative qualities and characteristics of Modular Essay

Compare the relative qualities and characteristics of Modular Information Systems against Integrated Software Systems in respect - Essay Example This information is produced to meet a business objective and it is valuable to the company. Information system is a set of elements which collect data, process and give the output data and information (Sommerville 2010). Business information systems are used by businesses and organizations for storing, processing and analysing data. The information systems are useful to the organizations since they enable the employees to recognize new patterns and relationships in the stored data. This enables the companies to make important decisions which ensure that the organization gains a competitive advantage in the market. The information systems ensure that the organizations activities are conducted efficiently and reliably and this improves the overall performance of the business. There are different types of information systems and this leads to variations in the functionalities of business systems. Computer systems are software programs that are developed to capture, store and manipulate data. There are different types of computer systems in the market and this depends mostly on the functionality of the software (Ajmani 2004). There are different processes of developing software programs and this result to different software products with different characteristics. The process of developing that system is crucial to the functionality of the systems. Modular information systems are comprised of different modules that are connected together. The development of this system is done by partitioning the overall system into distinct parts known as modules. The modules have different functionalities and are developed independently. This type of development is preferred by organizations which have different functionalities and require detailed processes in the software systems. The modules are then integrated to form one huge system which can be used by an organization to conduct its business activities. Integrated software systems are developed as single units and the func tionality of the system is achieved by the whole system. Most of the integrated software systems are off-the shelf systems which are bought directly from the software dealers (Bass,et al., 2008). The functionality of the system meets the requirements of the organization and there is no need for gathering specific requirements of the organization. Modular information systems are flexible. This is because it is possible to replace or add one component to the system without affecting the other rest of the system. This is useful in organizations that are involved in many activities which are dynamic (Clements and Kazman 2008). The new activities that are carried out by an organization might require the development of a new system to meet the functionality required by the organization. Organizations which have modular systems can easily integrate new modules to meet their requirements. This is effective as there is little interruption to the business activities since one module is only a ffected. Integrated systems might result to the disruption of the whole system as new functionalities to the existing systems cannot be added without affecting all the system processes. The modular information systems perform better than integrated systems. The modular systems are developed from requirements that have been gathered from the organization. This ensures that the system is developed to perform better in the