Lactic Acid

In this week I will write about an acid that is released when our muscles are without the presence of oxygen. This acid is called Lactic acid, is an organic compound with the formula CH3CH(OH)CO2H. It is a white, water-soluble solid or clear liquid that is produced broth naturally and synthetically. With a hydroxyl group, lactic acid is classified as an alpha hydroxy acid (AHA). In the form of its conjugate base called lactate, it plays a role in several biochemical processes. The lactid acid system is able of releasing energy to resynthesize ATP without the involvement of oxygen and is called anaerobic glycolysis. 

Glycolysis (breakdown of carbohydrates) produces the formation of pyruvic acid and hydrogen ions. The pyruvic acid molecules undergo oxidation in the mitochondrion and the Krebs cycle begins. A build up of H+ will make the muscle cells acidic and interfere with their operation so carrier molecules, called nicotinamide adenine dinucleotide (NAD+), remove the H+. The NAD+ is reduced to NADH that deposit the H+ at the electron transport gate (ETC) in the mitochondria to be combined with oxygen to form water. Furthermore, if there is insufficient oxygen then NADH cannot release the H+ and they build up in the cell.

To avoid the rise in acidity pyruvic acid accepts H+ to produces lactic acid that then is dissociates into lactate and H+. Some of the lactate is diffuses in the blood stream and takes some hydrogen ions with it as a way of reducing the H+ concentration in the muscle cell. Our muscle cells normally have a  pH of  7.1 but if the build up of H+ continues and pH is reduced to around 6.5 then muscle contraction may be impaired and the low pH will pain (the burn). This point is often measured as the lactic threshold or anaerobic threshold (AT) or onset of blood lactate accumalation (OBLA). 

How the lactic acid works in our body: https://www.youtube.com/watch?v=ZaRsOjfEHyM

1. http://www.scientificamerican.com/article/why-does-lactic-acid-buil/
2. http://www.brianmac.co.uk/lactic.htm

Immune System

Multicellular animals have cells or tissues only they are facing the threat of infections. Some of these responses are immediate, so that an infectious agent can be contained quickly; others are slower, but also more specific for the infectious agent. Collectively, this protection is known as immune system. The human immune system is essential to our survival in a world full of potentially dangerous microbes, and a serious deterioration, can even a branch of this system, making us susceptible to serious infections that endanger life. Something that helps us to create resistance to pathogens in our system is immunity, this is the active ability to resist disease. The inmunity has two ways of working in our body, innate immunity and adaptive immunity.

Innate immunity, the body's built-in ability to recognize and destroy pathogens or their products, is lagerly a function of phagocytes, cells that can ingest, kill and digest most microbial pathogens. Innate immune responses develop within hour after contact and infections with a pathogen. Structural features such a the cell wall constituents shared by many pathogens interact with universal receptors on the phagocytes. The interactive phagocytes then active genes that lead to pathogen destruction.

Some pathogens are, however, so virulent that innate responeses are not completely effective. When this happens, the innate response phagocytes activate adaptive immunity to deal with these infections. Adaptive immunity is the acquired ability to recognize and destroy a specific pathogen or its products. Adaptive responses are directed at unique pathogen molecules called antigens. Phagocytes present antigen molecules to lymphoctes, key cells in the adaptive response. The antigens bind specific receptors on the lymphocyte, triggering genes that promote lymphocyte multiplication and production of pathogen-specific proteins that interact with the pathogen, marking it for destruction. A protective adaptive response usually takes several days tos develop; the strength of the adaptive response increases as the numbers of antigen-reactive lymphocytes increase.

So comparing the innate immune response between adaptive immune response, is that the recognition mechanism of innate immunity is that has rapid response (hours), is invariant, limited number of specificities and constant during response. However, the recognition mechanism of adaptive immunity is that has slow response (days to weeks), is variable, numerous highly selective specificities, improve during response, and is able to recognize old pathogens because the cells of this system have memory to destroy the old pathogens. Both immune systems have a common effector mechanism for destruction of pathogens. This video explain to you how our immune system works in presence of a pathogenic bacteria https://www.youtube.com/watch?v=zQGOcOUBi6s

This information will be found in the textbook,  Brock Biology of Microorganisms, 14th Edition- Madigan 

Skin

Today I will write about an organ that is very important to the human body, the skin. Without this organ the human body will have an ugly appearance. Really if we do not have skin what we would see would be our muscles. The skin is the largest organ of the body, made with several components, including protein, lipids, water and different minerals and chemicals. The skin protects us from microbes and the elements, helps regulate body temperature, and permits the sensations of touch, heat, cold and it is made to be tough and stretchy. Skin has three layers: the epidermis, the dermis, and deeper subcutaneous tissue (hypodermis).

The skin color is created by cells called melanocytes, which produce the pigment melanin. Melanocytes are located in the epidermis. The first layer is the epidermis, the outermost or top layer of skin, the part of the skin we can see, provides a waterproof barrier and creates our skin tone. It is too super thin on some parts of our body (eyelids) and thicker on others parts (the bottoms of our feet). Is the layer in charge of making new skin cells. This happens at the bottom of the epidermis and the cells travel up to the top layer and flake off, about a month after they form. In addition, giving skin its color, the epidermis makes melanin, which is whats gives our skin its color. Furthermore, protecting our body, the epidermis has special cells that are part of our immune system and help our stay healthy.

The second layer is the dermis,beneath the epidermis, it is much thicker and does a lot for our body, contains tough connective tissue, hair follicles, and sweat glands. This layer is in charge of making sweat, there are little pockets called sweat glands. They work making sweat, which goes through a small tubes and comes out of pores (sweating keeps us cool and helps us get rid of bad stuff our body does not need). Too, is in charge of helping our feel things, nerve endings in this layer help us feel things. The nerve send signals to our brain, making us know how somethings feels if it hurts, is itchy or feels nice when us touch it. The dermis is where we will find the roof of each tiny hair on our skin. Each root attaches to a tiny muscle that tightens and gives us goose bumps when we are cold or scared. This layer too make oil, and the oil keeps our skin soft, smooth and waterproof. Sometimes the glands make too much oil and give us pimples. By last, blood feeds our skin and takes away bad stuff through little tubes called blood vessels.

The last layer is the deeper subcutaneous tissue (hypodermis) or subcutaneous fat that is made of fat and connective tissue. The layer that have an important role in the body, has a special connecting tissue that attaches the dermis to our muscles and bones, and the blood vessels and nerve cells that start in the dermis get bigger and go to the rest of our body from here. Is the layer that helps keep our body from getting too warm or too cold. The fat pads our muscles and bones and protects them from bumps and falls.

This information can be found on this web page https://www.aad.org/public/kids/skin/the-layers-of-your-skin

Cloning

This week I'll write about a topic that is very important for science and that overdosed boom in recent years. The process of producing similar populations of genetically identical individuals that occurs in nature when organisms such as bacteria, insect or plants reproduce asexually, is called cloning. There are different types of cloning: molecular, cellular, organismal naturally, artificial, reproductive, therapeutic, replacement generation and extinct species. Today I will focus on the molecular, cellular, organismal naturally and reproductive cloning. Now I will explain each of these types of cloning.

Molecular cloning is the process of making multiple molecules, commonly is used to amplify DNA fragments containing whole genes and also can be used to amplify any DNA sequence such as non-coding sequences, promoters and randomly fragmented DNA. Cellular cloning is when is derived a population of cells from a single cell. Then in nature some plants and single-celled organisms, such as bacteria, produce genetically identical offspring through a process called asexual repoduction. Furthermore, natural clones occur in humans and other mammals. The identical twins are produced when a fertilized eggs splits, creating two or more embryos that carry almost identical DNA. 

Finally, reproductive cloning is also known as somatic cell nuclear transfer. It is a technology used to generate an organism that has the same nuclear DNA as another organism. The genetic material of the core is transferred from a differentiated and donor adult cell to an egg or enucleated egg. When electroporation (electric shock) or chemical treatment (ionomycin) is used, the pores open and the DNA enters to enucleated egg.Too, the cell is stimulated to divide. Once the appropiate time acquires embryo is transferred into the uterus of a female until birth. 

An example of this type of cloning is Dolly the sheep. This sheep was the first mammal cloned in this way. Dolly was cloned on February 27, 1997 by Ian Wilmut. She died on February 14, 2003 because developed lung cancer, arthritis and weak inmune system. In the case of Dolly the genetic marker was the color of th head of sheep that donated the egg. In addition, other cloned animals like Dolly were goats, cows, mice, cats, rabbits and gaur. In 2001 the first animal cloned endangered (gaur). This animal died forty-eight hours after infection. And in Italy was cloned a type of wild sheep (mouflon) who still lives.

Most of this information was obtained from https://en.wikipedia.org/wiki/Cloning and https://www.genome.gov/25020028
The example of Dolly and the information below of the example was obtained from my genetic class that I took on spring semester of 2015 (January-May).

Antibiotics

Antibiotics are powerful medicines that fight bacterial infections. Correct use can save lives. Antibiotics kill bacteria or prevent them from reproducing. After taking antibiotics, the body's natural defenses are sufficient. It is importante to know that antibiotics do not fight infections caused by viruses such as cold, flu, most coughs and bronchitis, and sore throats, unless caused by strep. 

When you use antibiotics unnecessarily would only increase the risk of antibiotic resistance, so they are not routinely use. Antibiotics can be provided in several ways. Oral antibiotics, topical antibiotics and injections of antibiotics. The oral antibiotics are tablets, pills and capsules or a liquid, they can be used to treat most types of mild to moderate infections in the body. Topical antibiotics are creams, lotions, sprays or drops, they are often used to treat skin infections. By last, injections of antibiotics, they can be given as an injection or infusion directly into the blood or muscle, and are usually reserved for more serious infections. Furthemore, the mechanism of action of antibiotics are hat affectinhibiting the synthesis of the cell wall, inhibiting protein synthesis, DNA gyrase synthesis, among other effects. All this depends on the type of bacteria that the antibiotic is  affecting.

This video show to you how the antibiotics work in our body: https://www.youtube.com/watch?v=IVBCrzjOl40

Most of this information is from: https://www.nlm.nih.gov/medlineplus/antibiotics.html and http://www.nhs.uk/Conditions/Antibiotics-penicillins/Pages/Introduction.aspx