Biologists would like to understand how a bear, who eats continuously throughout the summer to lay down fat reserves for the winter, can have cholesterol levels that would be high for a human, but not suffer the hardening of arteries that one might expect. And what about the bone loss one would expect from months of inactivity?  Humans on bed rest can lose 3-4% of their hip bone minerals from lack of weight bearing exercise.  Bears show no signs of bone loss or osteoporosis as a result of their long rests.  It is likely that the genes involved exist in our cells too, but they just aren’t being used in the same way.

We clearly have a lot to learn from our hibernating friends. Teams of researchers in Sweden have actually been studying Brown bears to learn about these interesting phenomena.  How do you study wild Brown bears you ask?  You tranquilize them while they are hibernating, collect as many samples as you can, and get out before they wake up!  For the full story on hibernation, go to: http://www.sciencenews.org/view/feature/id/338318/title/Lessons_from_the_Torpid.

C. elegans Roundworm

The aging process is, and always will be fascinating to us.  It’s role in an organism’s ability to reproduce is currently being studied in worms at Princeton University. The microscopic roundworm C. elegans lives for about 21 days.  For the first nine of these days, hundreds of eggs are fertilized producing an abundance of offspring!  After day nine, the many remaining eggs won’t be used, as their quality is poor and they cannot produce viable embryos.  A process similar to this takes place in humans.  Women experience a sharp decline in fertility in their late 30’s. In worms and in humans this is an early sign of aging.

Interestingly enough, there are genes that play a vital role in protecting cells from the aging process!  In somatic (or non-reproductive) cells, these “stress management” genes protect proteins and affect the metabolism of the aging cell.  Scientists at Princeton have discovered that although oocytes (egg cells) also age with time, the activated genes are different than those used by somatic cells.   Reproductive cells use genes that protect from DNA damage, repair DNA damage and make proteins that help eggs split up their chromosomes correctly. Another finding is that the genes associated with longevity (how long a worm lives) are completely independent of the genes that extend fertility.

It makes sense that the cells responsible for carrying genetic information forward to the next generation devote a number of resources to preserve themselves.  Surprisingly, this had never been shown before.  This new understanding of the genetics of fertility, will most likely affect how doctors approach the question of infertility and develop methods to curtail the inevitable aging of our eggs!

For most of the year, deciduous trees are green because of chlorophyll in the chloroplasts.  This pigment helps harness energy from the sun to fuel photosynthesis, or food production.  In the fall, days become shorter and sunlight more sparse, so plants begin to prepare for the winter – a period during which they rely on stored nutrients.   Nutrients are stored and superfluous leaves are shed , but before that, the chlorophyll begins to disappear, revealing other pigments such as yellow and orange that weren’t visible before.  Sometimes during this process, new pigments (such as reds) are produced as well.

This is controlled by up to 35 genes that can turn on and off in response to the reduction of sunlight hours.  It is a great example of the interaction between an organism’s DNA and its environment, a phenomenon many people are unaware of.  The traits and characteristics of all living things are the result of a combination of its genetic makeup and its physical and chemical surroundings.  To learn more about this type of interaction, go to chapter 35, “DNA responds to signals from outside the cell.”

I happen to work at an institution where evolution is revered as the underlying theme that explains life and all of its processes.  For a biology teacher it’s a comfortable place to be.  I suppose I am spoiled. When I travel to schools, I am on occasion told by teachers how happy they are that I am presenting evolution for them.  It is a required part of the New York State science curriculum, but some of the teachers who are supposed to teach it, don’t want to.   It makes me wonder.  Are they uncomfortable with the science?  Are they afraid of parents or students lashing out at them?  Does the scientific theory of evolution somehow conflict with their religious beliefs?   I don’t know the answer.  I’m sure it’s a combination of several factors. 

My gut feeling is that most teacher reticence is due to lack of understanding.   I would feel very uncomfortable if asked to teach a topic I didn’t fully understand, and unfortunately this is what’s happening.   I think we need better teacher training, especially for elementary teachers who receive very little training in science.  Everyone who receives a degree in general education or in science education should have to complete a course in basic genetics and/or evolution.   This would significantly reduce the negativity associated with teaching evolution, and could help produce much happier teachers!

Interestingly enough, inhalable toxins can be detected in airways, just like they would be on the tongue. The airway response to detection is what’s most interesting.  One school of thought is that logically, when bitter toxins are detected in the lungs, the airways will close.  This prevents the toxin from entering the lungs, makes breathing difficult, and inevitably forces the individual to leave an unhealthy environment.

What has been observed though, is quite the opposite.  In mice, inhaled quinine (a bitter compound) caused the airways to relax, instead of constrict! In fact, quinine worked better than albuterol (a drug commonly used to treat asthma) at relaxing airways. There must be a benefit to having such a reaction.  It has been proposed that opening airways may reduce the risk of infection or aid in clearing infection when toxins are inhaled, but it is still unclear.  What is clear, is there will likely be new asthma medications developed in response to this interesting genetic trait!

We are in the midst of a media explosion surrounding the possibility of a vaccine for HIV. For years this has seemed a hopeless situation, so a great deal of effort and money has been spent on the campaign to educate people about transmission and prevent infection. Unfortunately, according to recent reports (http://www.mg.co.za/article/2010-07-12-hiv-vaccine-the-only-real-answer), the number of new infections is still an alarming 7400 per day!  In addition, less than half of the 9.5 million people in low-middle income households infected with HIV have access to anti viral treatments.

These staggering statistics demonstrate very clearly that efforts to help infected individuals are available and do reach millions, but they just aren’t enough.  Development of a vaccine, probably the best method of prevention, has been an extremely slow process. Students ask about this all the time. If scientists can eradicate small pox, if they can make a new flu-shot every year, then why can’t they make a vaccine for HIV? The virus mutates so quickly that once infected, the host harbors any number of viral variants, all unique!

Interestingly enough, one in four patients infected with HIV carry two very strong anti-HIV antibodies that seem to neutralize 91% of HIV strains (http://www.webmd.com/hiv-aids/news/20100709/antibodies-discovery-may-pave-way-to-aids-vaccine ). Why don’t they work? They usually aren’t produced until the infection is rampant, and by the time they are produced, the virus has begun to mutate!  So, the thought process is this: if individuals were given a vaccine that elicited the production of these antibodies before exposure to the virus, they would likely prevent infection upon exposure. The key now is development of the vaccine, and then dissemination to regions in need.

The identification and isolation of these antibodies have shed some light on what seemed to be an almost hopeless situation. I look forward to the next five years of research in this field and believe that there will be a vaccine in the next 10.

One of the cooking tips that I have picked up from all of the foodie shows I watch is to use fresh herbs, whenever possible.  Believe it or not, that green spring of parsley on my plate at restaurants that used to repulse me, has actually become a part of my regular cooking repertoire.  Turkey meatloaf just wouldn’t be the same without it!  My homemade pizza now seems bland without fresh basil.

The one herb that I just can’t get cozy with is Cilantro.   It turns out that I’m not the only one.  There are lots of people who also dislike the flavor of these green leaves, as well as their seeds (aka. Coriander).  The plant produces molecules called aldehydes, that determine its scent and taste.  It turns out that aldehydes are also found in soaps and lotions, hence the soapy taste that some report.

It is known that genes play an important role in taste, but there isn’t sufficient data in this field to pinpoint specific genes or gene variants to explain the Cilantro phenomenon.  It is also known, that the evolution of taste and smell has played an important role in our survival.  It’s possible that the cilantrophobe’s distaste is a result of the choice some of our European ancestors made when they turned their noses up at the herb, hundreds of years ago.

In the article, “Cilantro Haters, It’s Not Your Fault” by Harold McGee of the New York Times (http://www.nytimes.com/2010/04/14/dining/14curious.html?partner=rss&emc=rss?)  cilantrophobia can be overcome, through association of the flavor with positive experiences.  Makes sense, but I’m not sure I’m even willing to try!

This unique, and very desirable trait in my opinion, is most likely due to a genetic variation in my father’s immune system. Interestingly enough, it is believed that viruses have played an important role in the evolution of an estimated 139 genes that control susceptibility to viral infections. These genes have been influenced over thousands of years by exposure to different viruses, in different geographic locations.  The selective pressure created through exposure has led to the accumulation of many genes that give their hosts “protection” from certain viruses.

Understanding how these genes and their protein products function is useful!  Is it possible that they might play an important role in the development of better treatments for specific viral infections, some kind of gene therapy to prevent viral infections like a “gene vaccine”, or maybe even cures! Although I always admired his ability to resist the stomach flu, I now see him in a new light.  He’s living proof that these genes exist, and that variety really is the spice of life!

To read more about viruses and human evolution go to:

http://www.sciencedaily.com/releases/2010/02/100218203053.htm

For example, when someone has hemophilia (a blood clotting disorder), there is a mutation in a gene that normally tells our cells how to make proteins called clotting factors. The mutation prevents a specific clotting factor from being produced, and as a result, the individual carrying the mutation has the disease and the blood doesn’t clot as it should after an injury. It’s a gene we all have, but if someone has hemophilia, the gene just isn’t working properly.

Another common misunderstanding is that if a disease is genetic, it is always inherited. It is true that many disease-causing mutations are inherited. Sometimes though, the mutations that cause genetic diseases develop over time, after we are born. Many of the mutations associated with the development of cancer, accumulate in our cells as we age, and aren’t inherited. These diseases are genetic, because they are caused by mutations in genes, but they aren’t passed from parent to offspring. Less than 10% of all cancers are inherited!

It’s no wonder that not only children, but adults too, are misinformed. These types of incorrect phrases and misinterpretations are printed all the time in magazine and newspapers. So where do you go for correct information? To learn more about the genetics of cancer, go to: www.insidecancer.org. To learn more about basic laws of inheritance, use DNA From the Beginning (www.dnaftb.org). To learn more about the inheritance of mutations that cause disease, go to: http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gnd, the Online Mendelian Inheritance in Men (OMIM) database.

A sea slug species, Elysia chlorotica, found in the marshes of New England and Canada has a unique trait. It produces chlorophyll and can use photosynthesis to make it’s own food – just like a plant! There are other organisms, not classified as plants, that have this trait as well such as the Euglena, a single-celled protist. This sea slug happens to be the first multicellular animal with such a trait. Scientists believe that they steal genes for this trait from the algae that they eat. They also steal chloroplasts, the organelle where photosynthesis takes place.

The stolen genes can be passed from one generation to the next, so that next generation sea slugs can also produce their own chlorophyll. Interestingly enough, the babies still need to eat lots of algae to get the chloroplasts they need to carry out photosynthesis. So maybe there is hope for green people after all?