Home » Biology (Page 16)
Category Archives: Biology
A Breakthrough in Breast Cancer Treatment
Exciting, new gene therapy treatments for breast cancer are on the verge of making a breakthrough. With proper funding, these procedures could reduce the need for the surgical removal of organs.
By Rayan Kaakati, Neurobiology, Physiology, and Behavior
Being born female automatically enters one in a game of Russian roulette: About 1 in 8 women will develop invasive breast cancer over the course of their lifetime; for American women, breast cancer is the second leading cause of death (U.S. Breast Cancer Statistics).
Breast cancer is a disease that starts in the tissues of the breast and is statistically fatal for one in thirty-two women (Breast Cancer Facts). Many women, throughout recorded history, have succumbed to this malignant disease. Rapid advancements in research have been very promising for cancer cell-targeting medications and for gene modification techniques.
Medicine in the twenty-first century is still resorting to what the ancient Chinese and Arab doctors used to practice: “If cancerous, cut it out if possible,” or in current-day terms, order a “lumpectomy” or a “mastectomy” (if the entire breast is to be removed). In recent years, a toxic chemo “smoothie” and an intensive radiation regimen have been added, coupled with hormone therapy. While these medical procedures are credited with saving thousands of lives, they are still primitive compared to current, promising research works.
Learning from Drought in California: Past and Present
By Marisa Sanchez, Molecular and Cellular Biology, ’15
The most current drought in California is considered to be one of the worst droughts in the past century, and many wonder if this severity is due to climate change. However, California has had a long history of unpredictable weather fluctuations, and is familiar with severe droughts. Many droughts can have devastating effects, particularly in the agricultural industry and the hydropower industry. Most Californians have also experienced the effects of a drought first-hand, such as having enforced water rationing. Even though, California’s history has shown that most droughts have devastating effects, droughts can also great learning experiences.
Viruses and the Global Metabolic Pathway
By Oyang Teng, Biological Sciences ’14
Microbes are the planetary engineers of the biogeochemical cycles that sustain all life on earth. At the molecular scale, the biological turnover of such key elements as hydrogen, carbon, oxygen, nitrogen, iron and sulfur depends on the enzymatic transfer of electrons from reduced (electron-donating) to oxidized (electron-accepting) forms of these elements. On the global scale and over geological time, reduced substrates and oxidized products map to a vast, often circuitous flux between the interior depths of the mantle and the oceans, land, and atmosphere.
Arabidopsis – Model Organism
By John Tran, Biochemistry & Molecular Biology ’14
Have you ever wanted to learn more about the plant model organism?
Plants have many unique properties that make them especially important to all aspects of life. They provide oxygen, food, and energy, so you could imagine that there are many cellular and molecular processes that are involved in plants. For these reasons, we want to better understand plants using a model organism called Arabidopsis. Here, we talk about the properties of Arabidopsis and present an example of a genetic experiment, which could be used to improve the quality of apple trees.
Photo credit: “Arabidopsis thaliana – Acker-Schmalwand” by Nuuuuuuuuuuul is licensed by CC BY 2.0
When the Last Frog Croaks
By Renata Vidovic, Evolution and Ecology ’15
To some, the phrase climate change evokes images of dry lakes, melting icebergs, and rising oceans. However, the effects of global warming are not simply cataclysmic geological changes. There are links between all biotic and abiotic features of an ecosystem. Unsurprisingly, climate change has an immense impact on frog populations around the world. Home range, abundance, breeding cycles, pathogen epidemics, and physical degradation in frogs are all affected by the changing climate.
Is your spit making you fat?
One of the central pursuits of modern human genetics is to move beyond genomic correlation. That is, to demonstrate experimentally why a specific genetic variant may be associated with a disease. New work in Nature Genetics from an international team lead by Philippe Froguel at Imperial College in London does just this – demonstrating an interesting link between saliva and obesity. Basically, all humans express amylase, a salivary enzyme that breaks down complex carbohydrates into absorbable sugars. The researchers found that people with more copies of the gene had a significantly decreased risk of developing obesity. People with fewer copies expressed less amylase, and it was hypothesized that this alteration in gastrointestinal carbohydrate metabolism affected insulin signaling, blood sugar levels, as well as the microbial community in the gut. This finding has implications for the rational design of digestive enzyme-based therapies for obesity and other metabolic disorders.
Froguel, Philippe, et al. “Low copy number of the salivary amylase gene predisposes to obesity.” Nature Genetics vol. 46, p. 492-497 (2014).
Viral Evolution
By Mubasher Ahmed, Genetics ‘15
Viral evolution is an emerging field in biology that has great implications for human health. T7 is a phage virus, meaning it infects bacteria, and is a powerful model system in evolutionary virology. In a recent experiment, a team of biologists sought to understand the degree to which genetic elements engineered into the T7 phage genome affected the phage’s rate of propagation. In this context, the genetic elements are sequences of DNA that are inserted between genes that allow for researchers to manipulate gene regulatory networks. This allows biologists to probe how phenotypes change when gene-gene interactions are perturbed. Previous studies had shown that such genomic elements led to decreased fitness for the virus, but these investigators hoped to better understand how exactly such a system would evolve in laboratory conditions.
To address their questions, the scientists grew both T7 viruses with and without design elements in each of two conditions. One condition was in a nutritious broth that used one intestinal bacterium as a host, and the other in a glucose sugar medium that had a different host bacterium. Both T7 strains were allowed to grow for 700-1000 generations in the glucose media and 100 generations in the broth media. Limitless bacteria were provided for the phages in order to encourage growth, and the researchers hypothesized that their experiment would allow enough time for the maladapted viruses to slough off deleterious design elements through evolutionary adaptation. (more…)
Origin of the Y Chromosome
By Marisa Sanchez, Molecular and Cellular Biology ‘15
The genomes of male and female mammals differ by one chromosome. The Y chromosome is only present in males, and is responsible for initiating the physiological and morphological differences between the sexes. This has not always been the case though; at one point, the X and Y were identical, and over time the Y chromosome began to differentiate from the X chromosome and shrink in size. The Y chromosome today only has 20 genes, whereas the X chromosome has over 1,000 genes. (more…)
“No Ecosystem is an Island”
By Daniel Friedman, Genetics ’14
For years, ecologists have modeled the biodiversity of natural forests as if they were oceanic islands, adrift in an unlivable sea of humanity. However, research published in April in Nature by C. Mendenhall et al. suggest that this is not the most accurate or predictive way to think about these pockets of nature. By comparing bat diversity on countrysides and oceanic islands, they find that fragmented land ecosystems behave markedly different than their oceanic counterparts. They find that forest “islands” maintain species at higher overall levels of biodiversity than ocean islands, and also gain/lose species in unique patterns. This has relevance to humanity’s actions to support biodiversity on land, and suggests the need for new models, metrics, and strategies of conservation.
Mendenhall, C., Karp, D., Meyer, C., Hadly, E., Daily, G., “Predicting biodiversity change and averting collapse in agricultural landscapes”, Nature, 2014.
Image from Abu Shawka, 2009. Creative Commons.
Grass-fed or grain-fed?
By Jenny Cade, Biochemistry & Molecular Biology ’15
Eating grass-fed beef and pasture-raised chicken is the eco-friendly thing to do–right? Maybe not, according to a recent paper published in the Proceedings in the National Academy of Science. The study proposes that intensifying livestock production by transitioning from pure grazing to mixed systems–where animals are fed high-energy food like grains–could reduce livestock greenhouse gas emissions by 23% by 2030. Currently, livestock account for 14.5% of all anthropogenic greenhouse gas emissions, so such a reduction would be significant.
In contrast, a comment piece that appeared in Nature last month calls for increasing grazing to make livestock systems more sustainable. Of eight strategies that the authors outline to reduce the environmental and economic costs of raising livestock, “Feed animals less human food” is number one.