Introduction
What exactly causes the infirmities of old age? According to the free-radical theory of aging, oxidative damage caused by ROS (reactive oxygen species) is the main culprit. This paper focuses on a study that partly supports this theory by showing that murine life span can be extended by an overexpression of human catalase in mitochondria.
The specific paper that this is based on is Extension of Murine Life Span by Overexpression of Catalase Targeted to Mitochondria by Samuel E. Schriner et al. Another paper that was used in the construction of this paper is The Anti-Aging Sweepstakes: Catalase Runs for the ROSes by Richard A. Miller. These scientific papers are summaries of the experiments carried out by Schriner and his group dealing with the topic of catalase-overexpression and its effect on murine lifespan. However, it is important to remember that this is a topic still under much debate. Though these experiments do not provide us with a definat cureall for aging, it is believed by many that the data aquired from them point us to one of the major culprits of aging and age related diseases, ROS's.
Why the fuss over R.O.S.?
Attempts to prolong longevity have been a major endeavor in science and several hypotheses have been proposed about the major causes. Scientists have focused on the role of reactive oxygen species in longevity through investigations using mice models. Reactive oxygen species’ role in aging processes is also known as the free radical theory of aging. Scientists have found that reactive oxygen species attack molecules of biological systems and are the main cause for the functional decline of organ systems that lead to eventual death. Various experiments were conducted to investigate the role of reaction oxygen species using transgenic mouse models.
Specifically, the purpose of these experiments are to determine if minimizing the level of ROS (reactive oxygen species) in certain organelles in mice have any effect on the overall health and lifespan of the mouse. The hypothesis was tested by amplifying a certain gene in mouse DNA that expresses catalase, an enzyme that breaks down the ROS’s. However, prior to beginning the experiments, transgenic mice are necessary for the experimentation.
Development of a Transgenic Mouse
A transgenic mouse is a mouse that has had a specific gene, in this case the human catalase gene, inserted into its genome.
Living organisms undergo chemical reactions with the help of unique proteins known as enzymes. Enzymes significantly assist in these processes by accelerating the rate of reaction in order to maintain life in the organism. Without enzymes, an organism would not be able to survive as long, because its chemical reactions would be too slow to prolong life. The properties and functions of enzymes during chemical reactions can help analyze the activity of the specific enzyme catalase, which can be found in bovine liver and yeast. Our hypothesis regarding enzyme activity is that the aspects of biology and environmental factors contribute to the different enzyme activities between bovine liver and yeast.
Dr. Janis Eells presented a study that was accomplished by her and her students under the title “UNBLINDED BY THE LIGHT: Photobiomodulation for the Treatment of Retinal Degenerative Disease”. The purpose of this study is to determine whether photobiomodulation with near-infrared is able to treat retinal degeneration diseases. Thus, they hypothesis that the exposure of a rodent model of methanol toxicity to photobiomodulation (PBM) with near-infrared (NIR) could play a potential role in protecting the retina against the toxic actions of the methanol- derived formic acid. What is known about the topic is that if a small amount of methanol is injected it will rapidly cause permanent blindness. The methanol is metabolized to a mitochondrial toxin, and it is formic acid that can inhibit Cytochrome c Oxidase. This formic acid is able to interrupt mitochondrial function and increases oxidative stress in the retina and optic nerve which eventually leads to blindness. In order to fully test their hypothesis, the rats were randomly divided into four treatment groups: untreated control, LED-treated control, methanol-intoxicated, and LED-treated, methanol-intoxicated rats. they used electroretinogram as a sensitive indicator of retinal function, the experimental rats under methanol intoxication were exposed to three ...
Catecholase is an enzyme formed by catechol and oxygen used to interlock oxygen at relative settings, and it is present in plants and crustaceans (Sanyal et. al, 2014). For example, in most fruits and vegetables, the bruised or exposed area of the pant becomes brown due to the reaction of catechol becoming oxidized and oxygen becoming reduced by gaining hydrogen to form water, which then creates a chain that is is the structural backbone of dark melanoid pigments (Helms et al., 1998). However, not all fruits and plants darken at the same rate. This leads to question the enzymatic strength of catecholase and how nearby surroundings affect its activity. The catecholase enzyme has an optimal temperature of approximately 40°C (Helms et al., 1998). Anything above that level would denature the tertiary or primary structure of the protein and cause it to be inoperable. At low temperatures, enzymes have a slower catalyzing rate. Enzymes also function under optimal pH level or else they will also denature, so an average quantity of ions, not too high or low, present within a solution could determine the efficiency of an enzyme (Helms et al., 1998). Also, if more enzymes were added to the concentration, the solution would have a more active sites available for substrates and allow the reaction rate to increase if excess substrate is present (Helms et al., 1998). However, if more
The Effect of Temperature on the Activity of the Enzyme Catalase Introduction: The catalase is added to hydrogen peroxide (H²0²), a vigorous reaction occurs and oxygen gas is evolved. This experiment investigates the effect of temperature on the rate at which the enzyme works by measuring the amount of oxygen evolved over a period of time. The experiment was carried out varying the temperature and recording the results. It was then repeated but we removed the catalase (potato) and added Lead Nitrate in its place, we again tested this experiment at two different temperatures and recorded the results. Once all the experiments were calculated, comparisons against two other groups were recorded.
Investigating the Effect of Substrate Concentration on Catalase Reaction. Planning -Aim : The aim of the experiment is to examine how the concentration of the substrate (Hydrogen Peroxide, H2O2) affects the rate of reaction. the enzyme (catalase).
Investigating Factors that Affect the Rate of Catalase Action Investigation into the factors which affect the rate of catalase action. Planning Aim: To investigate the affect of concentration of the enzyme catalase on the decomposition reaction of hydrogen peroxide. The enzyme: Catalase is an enzyme found within the cells of many different plants and animals. In this case, it is found in celery.
Humans undergo several stages during their lifetime including growth, development, reproduction and senescence. Senescence is defined as the deteriorative biological changes that organisms experience as they age eventually leading to death. These changes include low metabolism, a weak immune system, memory loss, poor vision and loss of hearing. Senescence begins in humans during their post-reproductive years. However, gerontology research has shown that individuals who reproduce late have longer life spans compared to individuals who reproduce early. Nonetheless, it does not indicate that senescence is inevitable. All organisms experience senescence, but at different rates and time. Many genetic diseases such as Alzheimer’s disease and Huntington’s disease are prevalent in older individuals and the symptoms being to appear in middle adulthood. The causes of genetic diseases and disabilities in older individuals are explained by three evolutionary theories: antagonistic pleiotropy theory, mutation accumulation theory and disposable soma theory. These theories suggest that favorable natural selection and heavy allocation of resources for somatic maintenance during the reproductive period decreases the chances of genetic diseases in younger individuals.
The Effect of a Catalase on the Breakdown of Hydrogen Peroxide Aim To follow the progress of a catalysed reaction by measuring the volume of gas produced as the reaction proceeds. Using the initial rates of a series of experiments I will be able to find the orders of the reaction with respect to enzyme and substrate. Also to find out if concentration has an effect on the reaction when an enzyme is used to accelerate the breakdown of hydrogen peroxide.
Oxygen is an essential component for cellular metabolic processes. As a result of normal cellular metabolism, oxidative products i.e. oxygen free radicals or reactive oxygen species are produced. In eukaryotic cells energy is generated in mitochondria as a result of aerobic respiration and this oxidative metabolism is responsible for formation of various compounds. Nearly all of these compounds are advantageous but a small proportion could be lethal if produced in higher concentration. During normal conditions small quantities of oxidative products are necessary for certain sub cellular events, including enzyme activation, formation of disulfide bond during the folding of new proteins, signal transduction and gene expression etc. (Yu etal., 2002; Droge, 2002). Oxidative stress can be defined as the excessive production of ROS which are not adequately removed from the body, because of reduced antioxidant defense system or the ROS increases beyond the capacity of antioxidants. The balance between oxidants and antioxidants is vital because oxidative stress can cause oxidative damages to N.A, lipids and proteins. The most important ROS are superoxide anion (O2−), singlet oxygen (O2), hydrogen peroxide (H2O2) and highly reactive hydroxyl radical (OH-). Whereas, antioxidant defense system is responsible to give protection against ROS. These antioxidants can scavenge and destroy ROS. The major antioxidant enzymes are catalase (CAT), superoxide dismutase (SOD) PON ….. and glutathione system (Sies, 1985; Valko et al., 2007; Halliwell and Gutteridge, 1990).
Another study proposed that CR slowed aging process by increasing resistance to hyperoxidation. As aging progressed in yeast and other animals, the presence of free radicals increased in the cells. Usually, the levels of the...
In the 16th century, rumors of the Fountain of Youth had spread like wildfire. The thought of immortality, and everlasting youth had fascinated many old, and young adventurers. Most Eukaryotic organism cells are affected by a biological process known as aging. Effect of aging may include the advent of illness, disease, and ultimately death. Death, this fear of end existence had enthralled many people on the quest for prolonged longevity. Therefore, how do we extend our lifespan? Where is this “Fountain of Youth” ? Although the latter question may forever remain a lucrative theory. Perhaps the answer to prolonged longevity may reside on a little known region of a chromosomes, the telomeres.
Common sense seems to dictate that we are all going to die one day. As we all get older we crave to keep our youth, and to stay young forever is the ultimate dream. The thought of a possible immortality is just an added benefit. Even though we have strived towards this goal for centuries, have we obtained advances in successfully staying young forever? In Bill Gifford’s book “Spring Chicken: Stay Young Forever (Or Die Trying)” he explores these ideas of life and aging further. In this novel, he goes on a journey to try and debunk the mysteries and questions behind the new science of aging. He gathers information from tests and scientists from around the country to discover what really works to prevent or delay aging and what is just a hopeful hoax. He helps us figure out why we age and why aging
Catalase is found in every cell of every organism on earth, in humans it is used to breakdown hydrogen peroxide which is toxic to humans to useful elements to the body like water and molecular oxygen.
SÍTAR, M.E., YANAR, K., AYDIN, S. and ÇAKATAY, U., CURRENT ASPECTS OF AGEING THEORIES AND CLASSIFICATION ACCORDING TO MECHANISMS. .
The Effect of pH on the Activity of Catalase Planning Experimental Work Secondary Resources Catalase is a type of enzyme found in different types of foods such as potatoes, apples and livers. It speeds up the disintegration of hydrogen peroxide into water because of the molecule of hydrogen peroxide (H2O2) but it remains unchanged at the end of the reaction.