Many species belonging to the genus Clostridium are categorized as strict anaerobes because neither they nor key enzymes inside them are able to function normally during aerobic culti-vations, and stringent anaerobic conditions are required for their growth (1). Despite the gen-eral understanding about the sensitivity of clostridial species to O2, some strains possess me-tabolic mechanisms for withstanding, to some degree, the presence of dissolved oxygen (DO), and this phenomenon has been reviewed(2,3). Clostridium acetobutylicum strain ATCC 824, a widely investigated model for studies on the fermentative production of butanol, sus-tained growth after a shift from anaerobic to microoxic conditions (0-0.2 % DO)at the mid-exponential phase of growth, however, it ceased to grow on flushing the broth with a gas mixture of 5 % O2 / 95 % N2 (4).The O2-tolerance of C. acetobutylicum strain ATCC 824 in microoxic conditions has been attributed to the production of O2-induced polypeptides, which are presumed to play a protective role against toxic activated oxygen species such as superoxide anion and hydrogen peroxide (4).Studies on the oxygen stress-responses in the obligate anaerobes C. acetobutylicum and C.aminovalericum revealed the upregulation of gene clusters coding for O2-scavenging enzymes, including NADH : rubredoxin oxidoreductase (EC 1.18.1.1), glutathione peroxidase (EC 1.11.1.9), thiol peroxidase (EC 1.11.1.1), alkylhydroperoxide reductase (EC 1.11.1.15), and superoxide dismutase (5).Based on the findings of Kawasaki et al. (4,5), Hillman et al. (6) reported that C. acetobutylicum strain ATCC 824 perRmutants, survived aerobic incubation on agar plates for up to 50 days (6). The per mutants also survived oxidative stress in aerated liquid cultures for up to 3 hours before a decrease in cell viability was observed (6). However, at this stage (after 3 hours) if no further O2 was added to the broth culture, the perR mutants were able to reestablish anaerobic conditions by rapidly consuming DO in the broth (6). These reports (4,5,6) however, did not investigate the effects of oxidative stress on the production of solvents. Despite the presence of metabolic mechanisms in some clostridia for surviving short-term oxidative stress, these appear to be insufficient for establishing long-term survival under aerobic conditions.
Literature on the effects of oxidative stress on butanol-producing bacteria, all of which are strict anaerobes, remains limited. A fuller understanding of the effects of such stressants on metabolite production will provide insights into stress-specific responses in bu-tanol-producing bacteria and may reveal strategies for improving the yield of solvents.
Stout, M.A, et al. "Microbiology Lab Notebook". Lab handbook. University of Texas. Arlington. 2014. Print.
The purpose of conducting an experiment using various temperatures, pH levels, and enzyme concentrations was to observe the effects these factors had on the rate of horseradish peroxidase activity. Furthermore, testing how peroxidase reacts to different set ambient conditions and finding the conditions that allow for maximum rates. Enzymes are used in this experiment to demonstrate the importance of certain environmental conditions since they affect the speed of an enzymatic reaction in order to carry out life. An extract from horseradish is used as the enzyme since it contains peroxidase which has a highly accessible active site. The experiment was administered by using a spectrometer as a tool to measure oxygen production using an indicator called guaiacol which would allow the rate of horseradish peroxidase activity to be seen. Environmental circumstances, such as enzyme concentration, temperature, and pH, are tested by using guaiacol as an indicator of oxygen production and H2O2 as an oxygen producing agent. The ending results conclude that higher enzyme concentration can increase the speed of the rate of enzyme activity. The results also conclude
Risperdal Risperidone is an atypical antipsychotic used to alleviate the symptoms of schizophrenia. Schizophrenia is defined by its effects in altering perception, thoughts, or consciousness called hallucinations or delusions. It affects about 1% of the population, with about 2 million people affected in the United States. About 50% of those affected become severely and permanently disabled and dependent upon public assistance. Schizophrenics make up about 10% of the totally disabled population and as much as 14% of the homeless.
Gut bacteria keep humans healthy by stimulating the digestive process within the large intestines. In order for nutrients to be successfully absorbed in the colon, non-digestible carbohydrates are degraded by beneficial gut microbial. One example of an anaerobically respiring bacterium which dominates the large intestine is bacteroide thetaiotaomicron. This bacteri...
The bacterium Clostridium difficile is a strictly anaerobic, spore forming, bacillus. It is present as normal flora in the intestines in 3% of healthy adults.1 It forms spores for protection in inhospitable environments. When the spore finds the right environmental factors it develops into the bacterium. The spores can survive on surfaces for months waiting for the right environment to grow and thrive. It is Gram positive so it appears blue or purple when Gram stained and has a thick peptidoglycan cell wall. It produces Toxin A an enterotoxin that causes fluid accumulation and Toxin B a cytotoxin that causes cells to lose their structure and die. Clostridium difficile has an incubation period of anywhere from a week to a month.1 Therefore it may take someone a long time to figure out that they have it and they may have already passed it to someone else. The rate of infection is highest in females and people 85 years of age and older.1
...id, acetic acid, formic acid, H₂ and CO₂ as fermentation products which increases ecological, industrial and basic bioenergetics interests in this particularly thermophilic bacterial specie.
I agree with him that acetyl CoA is formed in aerobic respiration from pyruvate when the oxygen is present. However, he also mentioned that acetyl CoA is produced from Krebs Cycle which do not require oxygen. I agree with Moez, the Undergraduate TA that there is a contradiction of his statement on acetyl CoA. I believe that might be a typing mistake and he chose choice C acetyl CoA as the correct answer. In Adrian’s comment on real world application of anaerobic respiration, he mentioned that anaerobic respiration affects many processes such as assimilation of carbon dioxide to acetate. In addition to that, anaerobic respiration also affects processes in bacteria such as denitrification. When there is a limited supply of oxygen, bacteria synthesize energy through denitrification. Therefore, anaerobic respiration has a significant role on bacteria production of energy when oxygen is
In the late 1800’s it was discovered that papa-amino-phenol, could reduce fever, but the drug was too toxic to use. A less toxic extract called phenacetin was later found to be just as effective but also had pain-relieving properties. In 1949, it was learned that phenacetin was metabolized into an active but also less toxic drug, acetaminophen. Since then, acetaminophen has been sold under many over the counter brand names, most popular being Tylenol.
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).
Many factors, for example, pH and temperature affects the way enzymes work by either increasing the rate or determining the type of product produced (). The report, therefore, analyses the effects of the enzyme peroxidase in metabolic reactions and determining its optimum temperature in the reactions.
Molin, M., Yang, J., Hanzen, S., Toledano, M., Labarre, J. and Nystrom, T. (2011). Life span extension and H2O2 resistance elicited by caloric restriction require the peroxiredoxin Tsa1 in Saccharomyces cerevisiae. Mol Cell, 43 (5): 823-833. doi:10.1016/j.molcel.2011.07.027.
The Drug enforcement Administration has targeted as a top priority the illegal use of the prescription painkiller OxyContin in the wake of what the agency says is a dramatic and dangerous increase in the drug's availability. Simply crushing the tablet can negate the controlled-release effect of the drug, enabling abusers to swallow or snort the drug for a powerful morphinelike high. The tablet can also be crushed, mixed with water and injected. In this paper I discuss the abuse of OxyContin and other prescription painkillers.
In October of 1982, Tylenol, the leading pain-killer in the United States at the time faced a crisis. Seven people in Chicago were reported dead after taking Tylenol. 12-year-old Mary Kellerdman of Elk Grove Village, Illinois, Adam Janus of Arlington Heights, Illinois, his brother Stanley Janus, and his wife Theresa Janus, Mary Reiner of Winfield, Paula Price, and Mary McFarland of Elmhurst Illinois was the last victim of the cyanide-laced Tylenol capsules. This happened bﴱᄃecause there was Extra-Strength Tylenol capsules that had been distributed and tampered with. The capsules contained 65 milligrams of cyanide. The amount necessary to kill a human is five to seven micrograms, which means that the person used 10,000 times more poison that what was needed.. The tampering had occurred when the products reached the shelves. The connection between the deaths and the Tylenol was discovered within days by two off-duty firemen who were listing to their police radios. Phillip Cappitelli and Richard Keyworth were the men to make the connection and tell there superiors.
Bacterial cells, like plant cells, are surrounded by a cell wall. However, bacterial cell walls are made up of polysaccharide chains linked to amino acids, while plant cell walls are made up of cellulose, which contains no amino acids. Many bacteria secrete a slimy capsule around the outside of the cell wall. The capsule provides additional protection for the cell. Many of the bacteria that cause diseases in animals are surrounded by a capsule. The capsule prevents the white blood cells and antibodies from destroying the invading bacterium. Inside the capsule and the cell wall is the cell membrane. In aerobic bacteria, the reactions of cellular respiration take place on fingerlike infoldings of the cell membrane. Ribosomes are scattered throughout the cytoplasm, and the DNA is generally found in the center of the cell. Many bacilli and spirilla have flagella, which are used for locomotion in water. A few types of bacteria that lack flagella move by gliding on a surface. However, the mechanism of this gliding motion is unknown. Most bacteria are aerobic, they require free oxygen to carry on cellular respiration. Some bacteria, called facultatibe anaerobes can live in either the presence or absence of free oxygen. They obtain energy either by aerobic respiration when oxygen is present or by fermentation when oxygen is absent. Still other bacteria cannot live in the presence of oxygen. These are called obligate anaerobes. Such bacteria obtain energy only fermentation. Through fermentation, different groups of bacteria produce a wide variety of organic compounds. Besides ethyl alcohol and lactic acid, bacterial fermentation can produce acetic acid, acetone, butyl alcohol, glycol, butyric acid, propionic acid, and methane, the main component of natural gas. Most bacteria are heterotrophic bacteria are either saprophytes or parasites. Saprophytes feed on the remains of dead plants and animals, and ordinarily do not cause disease. They release digestive enzymes onto the organic matter. The enzymes breakdown the large food molecules into smaller molecules, which are absorbed by the bacterial cells. Parasites live on or in living organisms, and may cause disease. A few types of bacteria are Autotrophic, they can synthesize the organic nutrients they require from inorganic substances. Autotrophic bacteria are either photosynthetic or Chemosynthetic. The photosynthetic bacteria contain chlorophyll that are different from the plant chlorophyll. In bacterial photosynthesis, hydrogen is obtained by the splitting of compounds other than water.
Oxygen (O) is one of the most important ions present in the body, making up 61% of the body’s mass. It aids in the destruction of harmful bacteria, while preserving the bacteria that is beneficial for the body. Oxygen takes on its role, and transfers the bacteria absorbed into the lungs, to the cells, allowing for cell respiration. Oxygen allows for the replacement of old cells, protection of the new ones, production of energy from the food, and decomposition of other foods (“Oxygen and Human Body,” n.d.). Oxygen is also vital to produce an activity known as metabolism, which is ‘the sum of the physical and chemical processes in an organism by which its material substance is ...