division

Plants Do Division http://news.jic.ac.uk/

I thought that only humans can do arithmetic, but plants do division as well. I guess a brain with a neocortex is not required. New research shows that arabidopsis plants perform an arithmetic feat to know how to distribute stored energy during the night when there is no light, preventing starvation.

Plants get their energy from light through a process called photosynthesis. This involves breaking down carbon dioxide compounds into sugars. And we all know what awesome byproduct that gives us; oxygen! So during the day they store sugars, and during the night plants do division in order to distribute the sugars at a steady rate. This insight comes from new research done by the scientists at the John Innes Centre and found through the open access journal eLife.

It is vital that plants do division in order to be able to grow properly. Learning more about this process has some implications, such as possible plant hacking in order to achieve higher crop yields. This is already being done with GMOs.

Plants do division during night time. There are certain “mechanisms” in the leaves that measure how much of the starch is stored and how much time will pass until the sun rises. Plants also have a sort of an internal “biological clock” which allows them to guess when dawn will come. There are three clock genes that work together like a seesaw. When dawn comes, these genes instruct the plant to make two proteins, CCA1 and LHY. These proteins tell the plant that it is daytime. During the day these are destroyed, which allows for the third protein, TOC1, to be made. This tells the plant that it is night time. That last protein also tells the plant that it’s time to make the first two, so the whole process cycles again.

According to Professor Alison Smith,

the calculations are so precise so that plants prevent starvation but also make most efficient use of their food.

Using up the starch too fast will induce starvation, while using it up too slow will waste the unused starch. Scientists predict that there are two molecules that encode the information about how much starch is stored at a given time and time until dawn breaks. Let’s call these molecules S and T for the time being. The rate at which starch is consumed is set by the ratio of S molecules to T molecules. Because a ratio is actually a fancy way to say division, scientists are confident in the claim that plants are division experts.

Sources:

http://elife.elifesciences.org/content/2/e00669

http://news.jic.ac.uk/2013/06/plants-do-sums-to-get-through-the-night/

http://arabidopsis.info/InfoPages?template=arabidopsis;web_section=arabidopsis

http://www.plantsci.cam.ac.uk/research/webb/plantTime/clock.html

Aging Is Like Burning Disks
Source: http://www.clker.com/cliparts/3/f/a/c/11949944972104123906cdcopy.svg.hi.png

Why do we age? What is it that makes us age and grow saggy? How can we bring our youthful glow into adulthood and beyond? These are the questions that most women ask themselves. Joking, scientists and men alike ask the same questions. And you might find your answer in telomeres.

Brief Intro to Telomeres

Human cells divide at an average of 50-60 times in one lifespan. Every time they divide, the cell’s DNA has to be replicated. That way, a new chromosome can form and be used in the newly duplicated cell. However every time a cell duplicates, it comes at a cost. That is, the chromosomes get shorter and shorter. If they get short enough, the chromosomes can have their twining undone and our genetic data gets corrupted. Eventually, that cell dies.

Fortunately, chromosomes are like shoelaces with plastic caps. These plastic caps are what keep the shoelaces from getting undone. Chromosomes have their own plastic caps too. They are called telomeres. They are the extra DNA strands that a chromosome can afford to lose. They are what keep chromosomes from getting corrupt. So why are we not immortal? This is what an article from the University of Utah has to say about telomeres and division:

Yet, each time a cell divides, the telomeres get shorter. When they get too short, the cell no longer can divide and becomes inactive or “senescent” or dies. This process is associated with aging, cancer and a higher risk of death. So telomeres also have been compared with a bomb fuse.

They help to preserve genetic data when cells replicate in order to have fully functional healthy cells. RNA molecules are necessary in the process of copying DNA strands. Telomeres get shorter each time because these small RNA pieces need room on top of newly formed chromosomes.

Without telomeres, the ends of chromosomes would look like broken DNA, and the cell would try to fix something that wasn’t broken. That also would make them stop dividing and eventually die.

Telomerase, Cancer, and Aging

So is there something that keeps telomeres from disappearing? Actually there is an enzyme called telomerase. They fit on top of telomeres and are more prevalent in the younger years, however they also eventually disappear.

This is not the case for cancerous cells. Cancer cells activate the telomerase enzymes once the telomeres get dangerously short. This keeps the cancer cell’s DNA intact and allows them to multiply like mad dogs. In fact, measuring telomerase may be a new way to detect new cancer threats. If we learn how to stop telomerase from being activated, we may be able to make cancer cells experience aging just like healthy cells.

In one experiment, researchers blocked telomerase activity in human breast and prostate cancer cells growing in the laboratory, prompting the tumor cells to die. But there are risks.

Shorter telomeres are related to shorter lives. Unfortunately, there is no strong evidence yet that shows that telomerase can make cells immortal and prevent aging. There is also no strong evidence that raising telomerase levels would also trigger cancerous cells to form.

Laboratory tests have shown though that telomerase was able to keep human cells divide far beyond the average limit without becoming cancerous. If researched further, we can have a future where human cells can be mass produced for transplantation, especially in key roles such as cells that produce insulin for diabetes patients.

Sources:

Genetic Science Learning Center. “Are Telomeres the Key to Aging and Cancer?.” Learn.Genetics 12 March 2013 http://learn.genetics.utah.edu/content/begin/traits/telomeres/