Introduction to Peroxisomes: “Peroxisomal Proteins and Pathways in Drosophila” Discovered in the 1950’s, peroxisomes were found floating within a cell’s cytoplasm using electronic microscopy by J. Rhodin (Schluter, 2010). These were later classified as organelles and the functions of these organelles were also further discovered and understood. Peroxisomes are membrane-bound organelle that are found in all eukaryotic cells participate in many metabolic reactions within the cell.
These reactions include “? -oxidation of fatty acids, ? -oxidation of branched chain fatty acids and ether lipid biosynthesis” (Faust et al. , 2012). Alberts et al. (2002) state that these peroxisomes have the ability to remove hydrogen atoms from various fatty acids and hydrocarbons using oxygen in oxidative reactions, in an attempt to break down these reactants. However, by removing this hydrogen; toxic or volatile oxygen molecules, such as hydrogen peroxide (H?
O? ), are produced. Alberts et al. (2002) continues to explain that peroxisomes provide a protected environment in order to consume these toxic products with the use of enzymes like catalase and urate oxidas. This process of breaking down fatty acids may seem menial but a buildup of fatty acids can cause damage to various structures such as “the myelin 'insulation' sheath surrounding nerve fibers in the brain” (BSCB, 2012), causing various diseases. Faust et al. 2012) also indicates that there is a range of Peroxisomal diseases called peroxisome biogenesis disorders (PBDs) that can be due to any faults in enzymes used in peroxisomes that affect the nervous system and these disorders often result in death despite being “fairly rare inherited diseases” (BSCB, 2012). In order to appreciate the experiment and results obtained from the journal article “An Inventory of Peroxisomal Proteins and Pathways in Drosophila melanogaster,” one must have an understanding of the ? -oxidation and ? oxidation pathway. Alberts et al. (2002) describe that during ? -oxidation; fatty acids are broken down and converted to acetyl CoA which is later distributed to the cytosol for further uses. This process is also seen in mitochondria. Also; similar to mitochondria, peroxisomes are able to replicate themselves by transferring their proteins to the cytosol as they don’t have their own DNA or ribosomes (Alberts et al, 2002). The rate at which peroxisomes grow increases, the more material there exists surrounding the peroxisome.
The method in which this occurs, however, is still unknown. Faust et al. ’s (2012) journal article attempts to gain a better understanding of peroxisomes in Drosophila; as they are used to model many human diseases, thus providing some explanation to the method in which a peroxisome dysfunction leads to the disease state. Faust et al. (2012) explains that any diseases; including Zellweger syndrome and Infantile Refsum disease, are caused by peroxisome biogenesis disorder (PBD), in which a defect in peroxisome function leads to an array of medical conditions.
A large amount is known about the symptoms and the method that PBD occur, however what allows a peroxisome dysfunction to lead to a disease is still unknown. In Faust et al. ’s (2012) study, Drosophila proteins thought to be involved in peroxisome creation and preservation were analyzed and from these analyses; peroxisomal pathways that these proteins were hypothesized to take were also examined. This study did not have a direct conclusion to what causes peroxisome dysfunctions to lead to diseases, but it does provide a base for which further study can occur. Alberts B, Johnson A, Lewis J, et al. 2002). Molecular Biology of the Cell. 4th edition. New York: Garland Science. Peroxisomes. BSCB. Peroxisome. (n. d. ). BSCB: The British Society for Cell Biology. Retrieved October 20, 2012, from http://www. bscb. org/? url=softcell/peroxi Faust J. E, Verma A, Peng C, & McNew J. A. (2012). An Inventory of Peroxisomal Proteins and Pathways in Drosophila melanogaster. Traffic, 13, 1378-1392. Schluter A, Real-Chicharro A, Gabaldon T, Sanchez-Jimenez F. and Pujol, A. (2010) PeroxisomeDB 2. 0: An Integrative View of the Global Peroxisomal Metabolome. Nucleic Acids Res, 38, D800-5.