These modifications mediate and control key cellular processes such as transcription, replication and repair within the human genome. (Sharma et al., 2010) In contrast to DNA methylation, histone modifications can result in activation or repression depending on which regions are modified and also the type of modifications present. (Sharma et al., 2010) Various changes in histone modification occur in cancer. For instance, loss of histone acetylation, which is controlled by histone deacetylases (HDACs) results in gene repression. Oftentimes, HDACs are found to be profoundly overexpressed in various forms of cancer.
The first one has REC8 in the protein complex, while the second and third groups have Rad21L and Rad21Scc1 resectively (Uhlmann, 2011). The Rad21L containing group is thought to act as a foundation for lateral-element formation because only Rad21L recruits SYCP1. When the recombination is complete, Rad21L gets dissociated from the complex as a result of phosphorylation. This dissociation can result in synaptonemal-complex disassembly. Thereafter, the meiotic cohesin complexes containing Rad21Scc1 is bound to the chromosomes (Figure 1.8) (Uhlmann,
Transfection: One of the methods of gene transfer where the genetic material is deliberately introduced into the animal cell in view of studying various functions of proteins and the gene. This mode of gene transfer involves creation of pores on the cell membrane enabling the cell to receive the foreign genetic material. Transfection can be carried out using calcium phosphate (i.e. tricalcium phosphate), by electroporation, by cell squeezing or by mixing a cationic lipid with the material to produce liposomes which fuse with the cell membrane and deposit their cargo inside. The choice of methods of DNA transfer depends upon the target cells in which transformation will be performed.
The short term immune response is known as the Innate Immune System and the long term is known as the Adaptive Immune Response. Monocytes and macrophages, primarily involved in atherosclerosis, are part of the innate immune response. Macrophages have two main functions. They can act as phagocytes that engulf foreign particles or as antigen presenting cells. They receive signals in order to be activated.
They exert a wide range of functions in neuronal/glial proliferation, differentiation and apoptosis, as well as in maintaining the membrane permeability to ions and in the stabilization of synaptic transporters and receptors, the latest processes relevant to the generation and propagation of the nervous impulse and synaptic transmission.20,39,40 Moreover, cell and animal models underscore the key function of sphingolipids in the neurite growth and myelination of the cerebellum and forebrain, among other brain regions.41,42 Deficiency of ceramide synthase-2 that generates sphingolipids with C22-C24 fatty acyl chains results in 50% loss of compacted myelin and 80% loss of CNS myelin basic protein.42 Similarly, a 60% reduction of myelin-associated glycoprotein in the cerebellum and forebrain characterizes mice deficient in ceramide synthase-1, the enzyme that generates C18:0 sphingolipids.41 Interestingly, mice deficient of ceramide synthase -6, which generates C16:0 sphingolipids, as well as mice deficient of GM3 synthase that is responsible for one of the first steps in the production of gangliosides, both present hyperactive behavior and have been postulated as suitable animal models for
The regulation of metabolism may be from within the cell or outside. The metabolic flux can be regulated by non-equilibrium reactions. The intracellular regulatory strategies include allosteric enzymes, substrate cycles, enzyme interconversion cycles etc. the cyclic AMP and phosphoinositide systems are major mechanisms of signal transduction. Metabolism is also regulated by hydrophobic hormones which enter their target cells and are able to interact with intracellular receptor molecules.
The membrane is selectively permeable which certain molecules are allowed to enter and exit the cell. The transport of molecules that enter and exit out of the cell require an endomembrane system that separates and compartmentalizes the different cellular functions of a variety of organelles. In Cell Structures Involved in
This can occur through vesicles that are formed by throttling the plasma membrane and then penetrating into the cell (endocytosis), or they merge with it to free their contents (exocytosis) outside. There are three types of endocytosis known: • phagocytosis - very common among unicellular protists, who use it to feed themselves; in the human body, some types of white blood cells incorporate cells and foreign substances into phagocytosis. • pinocytosis - a constant activity of pinocytosis is carried out by the endothelium, the tissue that covers the blood capillaries and which allows the cells of the surrounding tissues to withdraw fluids from the blood. • Receptor-mediated endocytosis - a quick and efficient method for withdrawing substances that can be found in the environment even at low concentrations. Finally, exocytosis is important for the secretion of many substances, including digestive enzymes produced by the pancreas and materials for the construction of the plant cell wall.
Epithelial cell migrating across wound usually move along the basal lamina or fibrin deposits, this phenomenon is called contact guidance and is an important factor in epithelial migration. Epithelial migration is followed by increased mitosis of epithelium. Recent evidence suggests that a water soluble heat labile substance called chalcone which is secreted at the wound site is responsible for regulation for mitosis
In industry, in many biomedical appliances are used the phenomenon of peristalsis, such as finger pump, blood pump machine, heart-lung machine, dialysis machine. This mechanism was first introduced by Latham . He performed several investigations theoretically and experimentally to understand the phenomenon of peristalsis in the ureteral functions. After Latham’s significant works, Shapiro  and Fung and Yih  have described biologically and medically important reflux phenomenon. Vesicoureteral Reflux (VUR) is the backward flow of urine from the bladder into the kidneys.
This causes accumulated lipids to be caught in the endosomes. While some of these genetic diseases like Tay-Sachs only result in death, there are new theories that cell therapy could help in some like Gaucher disease. The glycogen storage diseases are Glycogen Storage disease, types I and II. Glycogen Storage Diseases can be found by taking a blood test. These involve enzymatic deficiencies.