Drafts

Vaccinations are an extrmely important part of our societies health as a whole. Vaccines do not only protect the recipient, they can provide protection for the immunocompromised in that community. Vaccinations work to prevent different diseases by training your immune system to fight them. Some diseases have been almost erradicatied in the United States because of vaccines. Certain groups are more vulnerable to diseases because they have a compromised immune system. These groups include the elderly, and people undergoing chemo therapy.  In areas where individuals choose not to vaccinate their children that endangers many more people than just their children. These rare diseases could easily come back as an epidemic if less people are vaccinated. Traveling from one country to another is so easy today, someone who is not vaccinated could come into contact with a disease that has been previously erraticated in the US. This could lead to an epidemic if the disease reaches a population of people who are not vaccinated. 

Chromatin Immunoprecipitation is an important molecular tool used to discover all parts of the genome that a transcription factor can bind to. Chromatin Immunoprecipitation, or CHip-Seq, involves the use of antibodies to bind to the transcription factor of choice in order to withdraw all the genetic material from the cells. The first step requires the crosslinking of proteins and DNA together. Once the Transcription factor has been attached to the DNA, the DNA is sheared into 300 base pair segments. Next beads with antibodies that recognize a specific transcription factor are added so that the DNA-transcription factor complex binds to it. The immunoprecipitation part of this experiment involves centrifuging the substance so that a pellet is formed containing only the beads that are attached to the DNA-transcription factor complex. The protein is then uncrosslinked from the DNA and the short strands now get sequenced. The sequenced DNA portions are then mapped on the genome to see where the transcription factors bind.

Skeletal muscles are a large grouping of cells with the intended purpose of contraction and relaxation. These two motions are what allows animals to move. Skeletal muscles are composed of myosin and actin filaments compacted into a small area known as a sarcomere. This sarcomere is the contractile unit of the cell. A strand of sarcomeres is known as a muscle fiber, a group of muscle fibers is called a fascicle, and fascicles make up a skeletal muscle. Skeletal muscles are actively controlled by the brain. When an organism wants to move their brain fires signals known as action potentials down a system of nerves to reach the muscle. The nerves connect to the muscle and when the action potential reaches this point the action potential is potentiated along the sarcolemma of the muscle. The sarcolemma is the muscle cells storage and transport system. Eventually while moving across the muscle, the action potentials travel down t-tubules, which activate voltage-gated ion channels. These channels open calcium stores to be released into the muscle.The calcium reaches the sarcomere and binds to troponin, a portion inhibiting myosin from binding to actin. Binding calcium to troponin causes a conformational change and exposes the active sites on actin. Myosin heads on the myosin are where contraction actually occurs. In there off state they are bound to an atp, which can be broken and release energy stored in the bonds activating the myosin head. In this state the myosin head can bind to the exposed sites on actin and pull/contract. At the same time the ADP and P molecules still attached release. Returning the myosin head to ‘rest’ requires an ATP to bind changing its conformation and decreasing its affinity for the binding pocket.

My dog is an 11 year old pure bred pomeranian, weighing 10lbs and his coat is white with brown spots. His face however is mostly brown, but half of his snout is white. As he has gotten older he has developed a few white spots on his nose and the color on his nose has changed from brown to pink. 

He is a little different than the usual dog and exhibits a few behaviors that are a little less common. For one, he has a small green bed he chews on, identical to babies with a pacifier, when he is excited and overwhelmed. He is very attached to this and knows when to look for it. Some events he will grab his bed for are phone calls, laughter, gatherings at the house, when people sit around the dinner table or play games, and when there are more than 5 people in the room engaged in a long conversation. 

He was never taught how to say “I love you,” yet when the phone rings, he will howl and the vocalization that comes from his mouth is very similar as if he were saying those words. 

He knows a lot of the human vocabulary. This includes all of my family member’s names and our close friends. He knows many tricks and also knows various places in our house by name (downstairs, living room, my room, parent’s room etc) and will travel there when asked, and he knows what his bed is, and will retrieve it when asked. 

One thing that surprised me was how he learned not to leave the front yard. When he was a puppy he would attempt to escape from the front door and has successfully done so twice, but as he got older I would bring him outside and he did not pass the grass and would never go onto the street. He’s become very attached to the house such that when he comes home from a walk and you release his leash down the street, he will spring home and wait at the front door barking (impatiently) for it to be opened.

If not all family member’s are in the same room, he will do routine checkups and find each of us before going back to where he originally was. For example, If he is with me in the living room but my parents were outside and my sister was in her room, he will leave the living room occasionally to check outside, then go to my sisters room, and will come back to the living room. 

There are many more behaviors I could go into, especially his personality, but that would take a whole dissertation to write. 

Moth and bat coevolution is a classic example of the intersection of behaviour and neurology. Bats locate their prey through echolocation, a process by which a bat emits ultrasonic waves and uses the reflection of the sound to locate itself in space and to find food. Bats have to eat at least once an hour to support their metabolism and so there is strong selection for bats that can echolocate efficiently. Similarly, moths are under heavy selection pressure to avoid becoming food. To sense the direction of their bat predators, noctuid moths possess two sensory nerves connected to their tympanum. The A1 nerve fires more frequently as ultrasonic sound gets louder and the A2 nerve only fires when ultrasonic sound is particularly intense. Each side of the moth thorax has a tympanum and its complementary pair of nerves. This allows the moth to determine the direction from which the bat is approaching. If the sound is louder on the right side than the left, then the moth knows the bat is coming from the right side. If the sound is louder when the moth has its wings up and softer when its wings are down, then the bat is coming from above. Within the three metre echolocating range of the little brown bat, its primary predator, the noctuid moth can sense the direction from which the bat is arriving and attempt to fly away from it. Should the bat get too close, the A2 nerves will fire causing the moth’s wings to beat out of sync and engaging the moth in a spiraling power dive. During this erratic movement, not even the moth knows where it will end up, though usually it will crash land in bushes that will mask its position. This evolutionary arms race is but one of many where there are heavy selection pressures on both predator and prey.

Bird banding is a process which birds are caught, processed, and recieve a band around their leg. The band has identification numbers on it which can be used to track the exact bird when it is recaptured or found dead. Birds are caught in a fine net called a mistnet, specifically designed for catching birds and bats. The bird flies into the net not seeing it's there, and tumbles down into a pouch like protrusion at the bottom of the net where they can be picked up out of easily. The bird is often evaluated and processed, taking measurements, checking for disease, or recording the number on the band if the bird already has one. Once these tasks are complete, the bird is released back into the same area it was caught in. This identification system is used across the world for a variety of reasons. Banding and tracking allows scientists to study not only the birds themselves, but their effect on the world around them. For example the spread of disease by birds can be tracked through the use of these bands. Dispersal of plants through seeds that the birds eat can be followed and mapped based on where they have been tagged. 

Before beginning a loss of function experiment, the exact location needs to be identified on the mouse brain atlas. Once this area is identified, the coordinates for this location will be calculated. The coordinates will be inputted into a sterotaxic device and a lesion will be made in the mouse. Once the lesion is made, the mouse will be observed for behavioral difference over a set period of time. At the end of the experiement, the mouses' brain will be collected and preserved with formadehyde. It with then be fixed, frozen and placed in a vibratome to be sliced into either a sagittal, coronal or horizontal samples. The sample will then be stained using IHC (immunohistochemistry). This will give scientists the ability to see exactly what happened in the brain during the experiment. 

A topic of life science I’d like to explore is homeopathy, an alternative take to medicine. Homeopathy is defined as a system of alternative medicine based on the doctrine “like cures like,” claiming that a substance that causes the symptoms of a disease in healthy people would cure similar symptoms in sick people. This is interesting because as a student who wants to practice medicine in the future, I do not understand how, for example, injecting a virus into a sick patient, would make them feel better. It is common knowledge that medication is used to cure a disease, which contradicts homeopathy. Another doctrine that homeopathy follows is “potentization.” The claim states that disease-causing ingredients in a substance would be more potent in a diluted setting, enhancing the effects. This does not make sense either because the more diluted a solution, the less concentrated/powerful it is. An external resource goes so far to say that if scientists want a single atom of the disease-causing substance (the most powerful way to enhance the effects) is to dissolve the single atom into 1*10^20 parts of water, making a pill that would be as long as the distance from the Earth to the Sun (150,000,000 km), “a pill so massive it would collapse into a black hole under its own mass.” The third doctrine that backs the second one up is that “miasms” exist in solution. Essentially, a “bad air” or “spirit-like essence” is left inside the solution after extreme dilution, making the solution useable. We now know today that these doctrines are not true, and we do scientific research and experiments to know what works and what doesn’t work.

Throughout history, there have been many different perspectives on brain function. The ancient Egyptians believed that the brain did not aid in any higher order function. During mummification, they would remove the brain as they thought it was an unecessary organ for the afterlife. They belived that conciousness, memory and soul was located in the heart and higher order functions travelled through the blood. This theory was adapted and altered by other scientific figures such as Andreas Vesalius, who  believed that brain fluid carried higher order functions throughout the body. Theories on brain function continued to arrise as neurobiology became a more popular area of study. Yet, it was not until the mid-1600s, when Thomas Willis officially coined the term neurobiology, that the study of the brain became a legitimized form of research. 

The idea of a gay gene has been long debated and sought after among geneticists. After years of persecution and discrimination, some members of the LGBT community support such a search, in the hopes of scrapping the argument that their way of life is unnatural. Others vehemently oppose it, however, since they claim that it will only open up a worse form of discrimination. Those who oppose same-sex relationships may be able to alter their children's genetic makeup if it is revealed they have a homosexual predisposition. In a recent international study, however, a single genetic marker for homosexuality now seems rather unlikely. What seems more likely, however, is partial polygenic predisposition in conjunction with environmental factors. As with most genetic conditions, a cut and clear SNP, indel, etc are usually not responsible for an entire phenotype, but rather a group of genes working together for that expression. While this polygenic expression of phenotype allows for more diversity, it of course results in a much more difficult time deciphering the genetic origins of human and animal behavior.