BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: experiments on mice

The Behavioral Causes of Obesity

Obesity is a big issue that is affecting the world today. Obesity is mostly caused by abnormal eating habits, which include overeating, but little is known about what causes overeating. To further understand the behaviors that lead to overeating and obesity, scientists from the Centre for Genomic Regulation and the Pompeu Fabra University in Barcelona, Spain conducted research on mice. There findings were published in Addiction Biology.

The scientists put the mice in an environment where they are only fed high calorie foods. Their diet consisted of chocolate bars and their normal food. As the mice started to gain more weight, they started to become addicted to chocolate and started binge-eating it. They would eat the chocolate over their normal food, even though they were more full from eating their own food. Their new binge eating habits also changed their eating schedule. They started eating during the day, rather than at night.

In conclusion, this research made scientists aware that some people can be trapped in a binge eating state which can lead to obesity. Obesity is not just a metabolic disease, but is caused by behavioral issues. This research is helpful because people can now take preventative measures and go to therapy to change these eating habits. This research is very interesting because it can help solve obesity issues. To learn more about obesity behaviors and treatment, click here and here. 

Striped Field Mouse

 

Bacteria Not So “Bad”, After All?

Photo Link: Wild Garden of Gut Bacteria, By: Nicola Fawcett

Most of us are used to the common notion that bacteria may not be the most beneficial factor in maintaining your health.  Thats why the results of a recent research study conducted by scientists at Babraham Institute in collaboration with colleagues in Brazil and Italy, yielding evidence that in fact good bacteria in the gut can control gene expression in our cells, is game-changing!

The research team, led by Patrick Varga-Weisz, made this discovery by studying the gut bacterias found within various mice. Their attention was quickly drawn to the mice that had lost most of their gut bacteria. It became apparent that in the mice with a very low amount of the bacteria within their gut, contained increased amounts of the “HDAC2 protein”.  When investigating deeper into HDAC2, it was found that increased amounts of this particular protein are associated with increased risk of colorectal cancer.

This new research also resulted in the finding that the amount of chemical markers on our genes, are increased by short fatty acids. These specific chemical gene markers, known as “crotonylations”, were only recently discovered and are newly classified as genome “epigenetic markers”. The researchers then found that by shutting down the HDAC2 protein, short chain fatty acids increase the number of crotonylations.

Ingestion of fruits and vegetables into ones healthy diet are vital – ultimately determining how chemicals produced by gut bacteria, affect genes in the cells of the gut lining. In other words, the short fatty acids, which come from those dietary elements, have the ability to move from bacteria into our own cells, and from there cause changes in gene activity and cell behavior.

In the end, the scientists were strongly convinced that the ability to turn off and on genes, is determined by changes in crotonylation. This inferred that the existence of crotonylation in the genome of cells is vital to protect the body from cancer. Therefore, the pretense of good bacteria is very important for the prevention of disease and illness in the body!

As someone with a strong passion for the science, and also very influenced and intrigued by medicine, I very much enjoyed this study. As the boundary to curing cancer is still a hurtle doctors and scientists try to transcend everyday, studies like these, are both hopeful and fascinating, to me. Also, as someone curious about how the human diet ultimately affects the functions and inner workings of the body, this research again was very engaging and interesting!

Primary Source Article: How good bacteria controls your genes

Secondary Source: Wikipedia – Gut Flora (Gut Bacterias)

 

Gut Microbes and Parkinson’s Disease: A Fascinating New Study

Parkinson’s, a disease of the central nervous system, affects approximately one million people in the United States. While the disease known for impairing motor skills, it can also have digestive symptoms such as constipation years before diagnosis. Because of this phenomenon, scientists have begun to investigate the role of gut microbiome composition in this awful disease. One such study conducted by a team at Caltech used transgenic mice to get to the answer. All of the mice overexpressed the protein human a-synuclein, which can form the insoluble fibrils that lead to Parkinson’s. However, the researchers raised some of the mice germ-free, or gave them antibiotics, so no intestinal microbes formed. In these mice, Parkinson’s-like symptoms and brain pathology decreased. In addition, the researchers found that the mice that did have gut microbiota had brain inflammation that the germ-free mice didn’t. Only when the researchers fed the germ-free mice short-chain fatty acids (to stimulate gut microbiota) did they show signs of inflammation and other Parkinson’s symptoms. This suggests that gut microbiota that produce short-chain fatty acids could be what triggers this disease.

The researchers then tried to investigate more about which gut bacteria could cause Parkinson’s. Since different communities of gut bacteria live in people with Parkinson’s disease than in healthy people, they wanted to find out if these different communities are merely a byproduct or a cause of the disease. To do so, they transplanted human gut-derived microbes from Parkinson’s patients into some mice, and microbes from healthy people into others. The transgenic mice with microbiota from the Parkinson’s patients ended up with typical Parkinson’s symptoms like motor dysfunction. However, wild-type mice (mice that didn’t overexpress human a-synuclein) weren’t affected. This finding shows that people who are genetically predisposed to Parkinson’s can be afflicted with symptoms if introduced to microbes that are associated with the disease.

This is such groundbreaking work because it establishes a causality between the gut microbiome and Parkinson’s. It also raises questions about the negative affects of short-chain fatty acids on the mice in this study, since they’ve been known to be beneficial in humans. The researchers wish to continue their work by investigating the types of microbes in people with Parkinson’s to get to the fundamental cause of the disease and possible cures.

Do you think that short-chain fatty acids are actually harming humans in unseen ways? Is investigating human gut microbiomes is the right path to find the cure to Parkinson’s? Let me know in the comments!

Three-dimensional Human Intestinal Cells

Human Intestinal Cells Cultured with Gut Bacteria

Credit: Scitechnol Publisher, URL: https://flic.kr/p/fzFoNE

 

Original Article: http://www.the-scientist.com/?articles.view/articleNo/47640/title/Gut-Microbes-Linked-to-Neurodegenerative-Disease/

Study Shows Link Between Enzyme and Spread of Breast Cancer

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 “40,000 women in America will die of breast cancer in 2014.” This is a truly terrifying projection. Breast Cancer is an extremely deadly, and extremely prevalent cancer that affects the lives of millions each year. In my personal experience, I have many friends and family members that have battled against this cancer. So many are affected, and there is still no concrete cure. There is no cure, however, researchers at the University of California, San Diego School of Medicine have identified an enzyme that is closely related to the metastasis of breast cancer cells. This is great news, for it suggests the possibility of further research using this finding to end breast cancer for good. Xuefeng Wu, a lead scientist involved with this research, has stated that the team has been able to “target breast cancer metastasis through a pathway regulated by an enzyme“. This enzyme is called UBC13 and it regulates the activity of a protein called p38.

This p38 protein, when not in use, prevents metastasis. By identifying the enzyme that prevents the use of p38, researchers have come one step closer to preventing the spread of breast cancer in the body, and therefore defeating it. With the use of a lentivirus injected into the mammary tissues of mice, the scientists were able to suppress the functions of both UBC13 and protein p38. The mice grew primary tumors, as was expected, however the primary tumors did not metastasize and spread breast cancer cells throughout the bodies, which means the cancer was stopped from spreading throughout the body. This prohibition of the cancer cells to spread is a major breakthrough in breast cancer research and will without a doubt contribute greatly to the ending of breast cancer.

A big hearted snake

Credit: Flickr User Squamata55

For years the scientific community has been fascinated by the phenomena of snakes, such as pythons, eating massive meals at one time and breaking them down slowly over time.  Now thanks to a study by Leslie Leinwand there is an answer to how pythons manage this feat.  After the python eats its organs swell up to two times their size to accommodate this massive amount of digestion.  But what could cause an organ to swell this much?  Leslie and her team have an answer to this as well, fatty acids.  When they drew the snake’s blood after it ate they report that the blood was so filled with fat that it was opaque and it “looked like milk”.  Leslie and her team have not stopped their research here, in fact they learned that when they take three of the fatty acids found in the blood of these pythons and inject them into a living mouse the mouse’s heart will grow just like the pythons did.

This finding lead to another mystery for Leinwand and her team because they are still yet to discover how having large amounts of fat in the blood is harmless to a python while in a human it is incredibly damaging.  In an attempt to get answers Leinwand and her team have injected mice with heart disease with the three fatty acids that lead to heart growth to see if those lipids can have any effects on the condition.  Stay tuned…

Aging, a side effect of preventing Cancer?

Nobody wants cancer and about 50 years ago scientists found the body’s natural defense against cancerous cells which was either to kill the cells or to turn them into senescent cells. But in a recent study by The Mayo Clinic researchers they found that if you destroy these senescent cells then the health of the mice improves as the mice get older such as longer lasting fat deposits which would cause wrinkles if they had gone and prolonged development of cataracts. The original mice they had tested had shorter life spans than normal mice so they have started to test normal life span mice to try and replicate the results. The only problem is that the method used to destroy the cells in the mice is not applicable to humans because it requires altering the cells so that any cell which turns into a senescent cell destroys itself. The scientists have gotten around this by saying that people could develop drugs to block anything produced from the senescent cells so that they won’t actually affect the rest of the body. The have already been approached by people who are interested in these results and who want to start development on these drugs. The scientists say this does not actually extend life but it does extend the healthy part of life.

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