Diabetes: Feedback Mechanisms and Symptoms

In class recently, we learned about diabetes, specifically what is it, how it occurs, and why it occurs. We discovered that in diabetes, hormones do not properly regulate the glucose concentration in one’s blood stream. I’ve always know that diabetes had to do with an imbalance of sugars, but I never knew how it worked in a more in depth manner. I found it intriguing how there is a feedback mechanism for the distribution of glucose, something so small yet so important to the functioning of one’s body!

This process challenges me to think about how organisms have evolved over time to not just fit the niche of their environment, but to also internally maintain homeostasis. They have evolved to regulate the distribution of small molecules in the blood, making me think further about how simple the first organism must have been to not only survive but maintain homeostasis of all of the molecules present inside of it.

In the negative feedback control of blood glucose, there are two options that may occur. When the blood glucose level is too high, the pancreas releases insulin, which either stores glucose in the liver as glycogen or distributes the glucose in other cells. Therefore, the blood glucose level drops. When the blood glucose level is too low, the pancreas releases glucagon to trigger the release of glycogen from the liver to break down into glucose, causing the blood glucose level to rise. In a diabetic person’s body, the pancreas has trouble producing either insulin or glucagon to regulate the blood level of glucose.

I decided to research diabetes further to see how the regulation of blood glucose may affect the rest of the body. First I discovered that diabetes may cause increased thirst, increased urination, increased hunger, extreme fatigue, blurry vision, bruises slow to heal, and increased weight loss (Diabetes Symptoms 2014). In type 1 diabetes, it is common to loss weight while in type 2 diabetes it is common to feel tingling, pain, or numbness in the hands or feet (Diabetes Symptoms 2014).

           

Beyond these common symptoms, I found that the University of Leicester conducted a study “establishing a link between hypoglycaemia and increased risk of cardiovascular events and mortality in patients with diabetes” (University of Leicester 2014). Professors Kamlesh Khunti and Melanie Davies found this correlation with patients being treated with insulin, suggesting that patient’s treatments may change in the future (University of Leicester 2014). Specifically, they found that patients with diabetes have a 60% higher chance of cardiovascular problems due to atherosclerotic plaques in blood vessels (University of Leicester 2014).

While these findings increased my awareness of the seriousness of diabetes and taught me about its symptoms, I wonder how doctors will go about reforming the treatment to decrease the risk of cardiovascular problems.  Melanie Davies, a professor of Diabetes Medicine at the University of Leicester and Honorary Consultant at Leicester's Hospitals, agrees with this principle, suggesting that "going forward we need to focus on management strategies that help patients minimise their risk of having hypoglycaemic events" (University of Leicester 2014).

Work Cited:

University of Leicester. (2014, December 12). Link between low blood

glucose, cardiovascular events revealed. ScienceDaily. Retrieved

December18,2014fromwww.sciencedaily.com/releases/2014/12/141212085045.htm

Diabetes Symptoms. (2014, September 12). Retrieved December 16, 2014, from

http://www.diabetes.org/diabetes-basics/symptoms/

Did Life on Earth Originate from Outer Space?

A couple of weeks ago, we learned about the origin of life on earth both through watching an educannon video and a video in class. We learned that the earth was formed 4.5 billion years ago and that the origin of life could be traced through molecular evidence, geological evidence, and chemistry evidence.

According geological evidence, life most likely began 3.5 - 3.8 billion years, traceable through absolute and relative dating. Chemically, Miller and Urey performed an experiment to simulate the conditions of early earth, adding early atmospheric gases and an electrical charge equivalent to lightning, forming amino acids. Molecular evidence shows that the tree of life branched from a universal common ancestor that most likely had DNA, RNA intermediates, proteins, ATP, a lipid membrane, and cell division since every other form of life uses these today.

The most currently accepted idea is that life came from non-life or chemistry in shallow pools of water with the elements H, O, C, and N. However, the earth melting repeatedly due to collisions with meteorites would have wiped out any form of life developing immediately. Therefore, some scientists are suggesting that some chunks of earth flew into space after collision, containing the newly formed primitive chemistry, which could have survived the trip into space and back home through the same meteorite landing back on earth.

This idea of life coming from earth into space, surviving in space, and coming back to earth in meteorites blew me away. I was dumb struck to think that life could survive in space. This lead me to think that if life could survive in space, could life on earth have originated in space entirely and come to earth only by chance that a meteorite with life land on earth?

I researched this topic further and found that scientists from Cornell University have found that some amino acids and sugars exist inside of meteorites using the Alma Observatory in Chile (O’Callaghan 2014). Not only that, but they also discovered the presence of carbon 27,000 light years away, suggesting the possibility that life came from outer space (O’Callaghan 2014). In addition, they found hints of the molecule isopropyl cyanide (a complex molecule common in life-essential molecules) in the form of emitted radio waves from a giant gas cloud near the center of the Milky Way (O’Callaghan 2014). This means that the building blocks of life may have originated somewhere else in space and could have been brought to earth via meteorites. Their research has me questioning that if life did originate from space (I’m not solidifying that this is how life rose about on earth) and come to earth in meteorites, what is to say that these meteorites did not carry life to other planets as well? Could the same basic organic chemistry that evolved into life as we know it today be present on other planets?

Work Cited:

O'Callaghan, J. (2014, September 29). Did life on Earth come from outer space?

Discovery of carbon 27,000 light-years away suggests building blocks came from

elsewhere in the Milky Way. Retrieved October 29, 2014.

Coevolution: Planalto Hermit Humming Bird and Ornithophilous flower

Throughout the continuous evolution of new species over time, coevolution has been a mechanism for multiple species to selectively put pressure on each other, thereby affecting each other’s evolution. It has influenced the evolution of host species to stay resistant to parasites by reproducing sexually, which allows a higher chance of immunity. The parasite is pressured to evolve in response to have a better chance at infecting the host. This cycle continues as demonstrated in the Red Queen’s hypothesis (Cronk & Ojeda 2008).

Additionally, the Planalto hermit humming bird (Phaethornis pretrei) has coevolved a mutually beneficial relationship with the ornithophilous flower (Beloperone californica) (Faria & Araujo, 2008). The flowers itself are “characterized by having brightly colored (e.g. red or yellow) odorless flowers, tubular and evenly curved corollas, diurnal anthesis and sucrose-rich nectar” (Faria & Araujo, 2008). The plants have morphologically co-adapted these traits overtime with the hummingbird. Specifically, the flowers’ long and tubular shape appeals to hummingbirds because the bird’s bills are oriented similarly, allowing them to easily probe these flowers as opposed to other flowers (Cronk & Ojeda 2008). Over time, the plant species are selectively pressured to evolve flowers that are more tubular in shape, so that the hummingbirds will prefer to pollinate their flowers instead of other plants. In turn, the hummingbird species morphologically co-adapt a more similar shaped beak to fit smoothly into the flowers in order to get nectar. The plants have also evolved to produce a higher volume of nectar with a higher sugar production than other plants that are pollinated by insects to meet the birds’ energy requirements (Cronk & Ojeda 2008). The co-evolution patterns go as far as the plants’ flowers’ colors evolving to suit the humming bird specie’s vision. Birds prefer red pigmentation in flowers because they have a good sense of color discrimination and spectral sensitivity at the red end of the visual spectrum (Faria & Araujo, 2008). Therefore, the hummingbird has selectively pressured the plant species to evolve more red-toned flowers over the course of many generations., which encourages the hummingbird to take pollen from their flowers to reproduce instead of other plants. The convolutions have gone as far as the blooming times of the flower to coincide with hummingbird breeding seasons (Faria & Araujo, 2008).

Work Cited:

Cronk, Q., & Ojeda, I. (2008, March 7). Bird-pollinated flowers in an evolutionary and

molecular context. Retrieved October 19, 2014.

Faria, R., & Araujo, A. (2009, August 31). Flowering phenology and pollination of

ornithophilous species in two habitats of Serra da Bodoquena, Mato Grosso do
Sul, Brazil. Retrieved October 19, 2014.

Molecular Mechanisms of the Maternal Age Effect and how it can cause Down Syndrome

Before reading this article, I had a fair background on biogenetics from taking Honors Biology in ninth grade. More specifically, I understood the process meiosis, which is a specialized cell division resulting in sex cells (sperm and eggs). Errors made during meiosis may result in sex cells with the incorrect number of chromosomes. When conception occurs and a fetus begins to form, the original sex cell with an incorrect number of chromosomes will impact the fetus to have some sort of disorder. Individuals with down syndrome are products of this mistake in meiosis because their chromosome 21 has 3 replications instead of 2. I was also aware that as women age, the risk of their child having complications such as down syndrome increases dramatically.

However I didn’t know that this phenomenon is referred to as the maternal age effect and results in an increased risk of women having a fetus with an incorrect number of chromosomes by 30% (“Down Syndrome,” 2014). Dartmouth University continued to research this phenomenon in fruit flies and discovered that new protein linkages come about in immature egg cells post DNA replication and that these protein linkages are necessary for the cells’ sister chromatids to hold together (“Down Syndrome,” 2014). In their research, they reduced the amount of cohesion proteins after meiosis, which resulted in a loss of unity and chromosomes becoming unnaturally unorganized during meiosis (“Down Syndrome,” 2014). This shows that the cohesion linkage proteins are necessary for the cell’s proper division. In their continued research, they also discovered that once they exposed the cells to aging, cohesion was lost and a rejuvenation process in the fruit flies was unable to sustain it (“Down Syndrome,” 2014). Their results raised the question that if human meiosis and linkage proteins function the same way as fruit flies, does aging reduce the effectiveness of the rejuvenation process as well because it simply can’t supply the linkage proteins at the same rate as they are lost.  

After reading this article, I hope to learn more about meiosis and if there is a way to engineer replicates of the cohesion linkage proteins to make up for the rejuvenation process’s inability to sustain the proper amount to avoid errors in meiosis resulting in disorders such as down syndrome.

Dartmouth College. (2014, September 11). Molecular mechanisms of birth defects among older women: Why older women can have babies with Down Syndrome. ScienceDaily. Retrieved September 16, 2014 from www.sciencedaily.com/releases/2014/09/140911135440.htm