What you will find here

I will generally write about anything that happens to be in my head at the moment, whether it’s random science or just my feelings and experiences because I think it can be useful to people dealing with similar issues.

However, there will be some topics I will leave alone.  I chose to write under my name rather than choosing to hide under a pseudonym because I am willing to stand behind whatever I have to say.  I will avoid criticizing anyone who works with me or writing about things that may be politically problematic; which is more than I can say for a lot of bloggers.  For example, how would you feel if you found out that your boss was using a public website to complain about your perceived weaknesses?  Comparing you to your lab mates and describing you as petulant and childish; an obnoxious, abominable, unprofessional and condescending way to do things.

Paul Knoepfler’s piece in Nature talks about how blogging is a much more accepted means of communication by scientists today, and also addresses how not to blog.  The truth be told what you write can jeopardize your credibility in your department, or even your degree.  Of course it depends on how much has been written and what was said, but there is certainly no ignoring it.  Using a pseudonym is a pretty thin veil when it comes to one’s identity and I choose NOT to be the man behind the curtain.

I hope to be a source of knowledge, advice, suggestions and reassurance in the blogosphere for grad students, recent graduates and undergrads.

My life as a mosquito magnet

My life as a mosquito magnet

How come some people attract swarms of mosquitos while others –often nearby- rarely get bitten?  How come you get singled out and not the guy or gal next to you at the backyard BBQ?

Mosquitos primary senses are sight and smell, says Jonathan Day, a professor of medical entomology at the University of Florida in Vero Beach. Lab studies suggest that 20 percent of people are high attractor types, he says.

Mosquito’s vision is highly acute, especially later in the afternoon, and their first mode of search for humans is through vision, explains Day. People dressed in dark colours — black, navy blue, red — stand out and movement is another cue.  While standing completely still may not always be possible, unless of your course you are a robot street performer, wearing light colours can make you less conspicuous.

Once the mosquito locates a promising visual target, she (and it’s always “she” — only the ladies bite) then picks up on smell. The main attractor is your rate of carbon dioxide production with every exhale you take.  Larger people and pregnant women have higher rates of carbon dioxide production.  Your rate of carbon dioxide production also increases during exercise.  While you may be able to outrun them in a golf cart, it’s a big red flag for mosquitoes that says “meal time”.   Although carbon dioxide is the primary attractant, other secondary smells coming from your skin or breath mark you as a good landing spot.

Lactic acid (given off while exercising), acetone (a chemical released in your breath), and estradiol (a breakdown product of estrogen) can all be released at varying concentrations and lure in mosquitoes, says Day. Your body temperature, or warmth, can also make a difference. Mosquitoes may also flock to pregnant women because of their extra body heat.

Researchers are still uncertain behind a mosquito’s preference for certain people, says Joseph Conlon, a medical entomologist and the technical advisor to the American Mosquito Control Association due to more than 350 compounds isolated from odors produced by human skin.   Human odor and genetics are not the only factors, studies of twins have revealed it’s more complicated than that, suggests Conlon.

Conlon said that recent thoughts are it may not be what mosquitoes find attractive but what is repellent.  It could be that individuals who get less bites produce chemicals on their skin that make them more repellant and cover up smells that mosquitoes find attractive.

Mosquitoes don’t feed off you, since they feed off plant nectar, Conlon explains. Females use your blood to obtain a necessary protein for egg development.  I will try and forget this next bit of advice: Mosquitoes are more attracted to people after they drink a 12-ounce beer.

Here are more fun facts about mosquitoes and bites provided by our experts:

  • Eating bananas will not attract mosquitoes and taking vitamin B-12 will not repel them; these are old wives’ tales.
  • Some mosquito species are leg and ankle biters; they cue into the stinky smell of bacteria on your feet.
  • Other species prefer the head, neck and arms perhaps because of the warmth, smells emitted by your skin, and closeness to carbon dioxide released by your mouth.
  • The size of a mosquito bite welt has nothing to do with the amount of blood taken and everything to do with how your immune system responds to the saliva introduced by the mosquito into your skin.
  • The more times you get bitten by a particular species of mosquito, the less most people react to that species over time. The bad news? There’s more than 3,000 species worldwide.

Rite of Passage: Montezuma’s revenge

On our day off we went to visit the Mayan city of Tulum.  Tulum, one of the last cities inhabited by the Mayans, is situated along the east coast of the Yucatan Peninsula in the state of Quintana Roo, Mexico.  It was one of the best fortified Mayan cities helping it survive approximately 70 years after the Spanish began occupying Mexico.  It had numerous watch towers and was is protected on the seaward side by steep cliffs averaging 12 meters and on the landward side by a wall that averaged about 3 to 5 meters.  Although its strong fortifications kept the city safe from attacks and hurricanes it could not protect against disease.  Tragically its inhabitants succumbed to Old World diseases brought by Spanish settlers.

Quite comically, I suffered Montezuma’s revenge a day later, the common colloquialism in Mexico for travelers’ diarrhea, a mild or explosive (no pun intended) illness.  The name refers to Moctezuma II (1466–1520), the Tlatoani (ruler) of the Aztec civilization who was defeated by Hernan Cortes, the Spanish conquistador.  The revenge element of the phrase alludes to the supposed hostile attitude of countries that were previously colonized by stronger countries, which are now, in this small but effective way, getting their own back.

It was comical not due to the illness itself but the fact that I had visited the Mayan ruins, not the Aztec’s.  Therefore why did Moctezuma feel the need for revenge?  Although both civilizations were conquered by the Spaniards there were some important differences between them and the reason for my shitty time (pun intended) was not the ill will of a malevolent spirit but science.

Firstly the Aztecs were huge believers of human sacrifice and were at it all the time. The Mayans on the other hand believed in offering blood instead, though they were not averse to sacrificing the captain of a leading football team! But I digress, what really set the Mayans apart was there very scientific temperament. They studied stars and in fact had come up with a very scientific calendar comparable to the modern one. They had an obsession with time and tried to measure it by studying astronomy and correlating it with their current events.  If the Mayans had possessed the technology here is how they would have described Montezuma’s revenge.

The primary source of infection is ingestion of fecally-contaminated food or water…yummm! These sources have no adverse effects on local residents, due to immunity that develops with constant, repeated exposure to pathogenic organisms. The most common isolated pathogen is the enterotoxigenic Escherichia coli.  While other times it results from introducing different flora into your guts.

The symptoms I developed were diarrhea, abdominal cramps, low fever, malaise and bloating, with a nonexistent appetite.  Apparently the average person experiences four to five watery bowel movements each day.  However, I lost count after 20 “es mi dia suerte” I guess.  I tried a bunch of over-the-counter anti-diarrhea products with minimal success and 3 days later I was symptom-free and ready to take on the world again.

The truth is that in many ways I kind of knew I would eventually get Montezuma’s revenge, even though I took preventative measures.  It has a way of getting to travelers; especially those spending as much time here as I am.  It’s not something you can avoid unless you want to live in a bubble the entire time.

For me, it was almost a rite of passage.  That being said, Montezuma’s revenge seemed to get the best of me.  And for now, it’s time to move on to greener, and hopefully healthier, pastures.

Merits of Volunteer/Internships

For those lacking the serendipity of finding work immediately after graduating volunteer positions or internships can provide valuable work experience to bolster your CV.  Although most of these positions do not provide remuneration they are well worth it if you can afford too.  Many employers are hesitant to hire someone that they don’t already know.  So, whether you lack experience, have a limited professional network, or have just moved, volunteering is a way to get your foot in the door and let them know how great you are.

After graduating from Dalhousie in 2011 with a BSc(Hons) majoring in Marine Biology I applied to nearly 400 jobs with very limited success (4 interviews).  When I followed up to find out the qualifications of the successful candidates I was surprised to find that those getting entry level positions held masters degrees.  After talking to graduate students (masters and Ph.D), post-docs, associate professors, PIs, as well as folks from industry I decided that a volunteer experience would be a good way to gain experience and expand my network.

I just started a 3 month position with the NGO Centro Ecologico Akumal (CEA) to gain some scientific diving experience.  I am working in the Marine ecosystems program which consists of 4 areas: reef monitoring and Research, Bay monitoring and Patrol, Management and maintenance, Diffusion and Environmental Education.

I offer my two cents’ on the matter of these sorts of opportunities.  An opportunity to travel, meet new people and learn a new language is a very valuable life experience in itself; volunteering while doing it is a big asset on your resume.  It shows employers that you have initiative, you’re self-sufficient, and they know if you’ve worked in that environment you’re probably more resourceful for having done it.  It’s a great talking point in an interview.

Make sure you have spent time researching the organization and talking to past volunteers.  It should be a legitimate program, not ecotourism.  There are many great well-respected research stations (Smithsonian tropical institute, Bamfield Marine Science Center, Oceans Research, etc.) and others that are not so great.  Many programs are aimed at ‘gap year’ students and not for someone with experience looking to break into a specific field.  Make sure the organization makes good use of its volunteers, not that they just want to get your money and put up with you for x months to get it otherwise you will be learning a lot of new card games. To put it bluntly sometimes this is just a cheap way for people with no funding to get slaves.

Know what your career goals are and what experience and skills the opportunity will provide.  The people you meet and their network of professional friends may be an introduction into an employment opportunity.  Be sure to consider all your options.  Would volunteering at a lab to get a publication, or writing a chapter for a textbook be a better opportunity?  I worked a menial job for a year to put food on the table while volunteering at a lab to publish a paper which considerably raises the chances of receiving graduate scholarships (NSERC in Canada) before volunteering with CEA.  Another good way to gain experience is to find a PhD student that needs an assistant, you might find the experience more scientifically rewarding (and cheaper).  Texas A&M job board often has some interesting opportunities.  Sign up to various list-serves to hear about similar opportunities.

If you can afford to do some philanthropic labor, then I would say by all means do it – if anything, you may make some contacts that can lead you to a job. Networking is everything in this field, and the farther you stretch your fingers, the better.

I will posting updates and musing on my experiences over the next 3 months, so stay tuned.

Humidity helps terrestrial hermit crabs smell better

Olfaction in land crabs is still in an early transitional stage between life in water and on land

Max Planck scientists have discovered that the olfactory system in hermit crabs is underdeveloped in comparison to that of vinegar flies. Vinegar flies have a very sensitive sense of smell and are able to identify various odor molecules in the air.  Flies olfactory sense is not influenced by the level of air moisture at all, while humidity significantly enhanced electrical signals induced in hermit crab antennal neurons as well as the corresponding behavioral responses to the odorants.  Furthermore crabs recognize only a few odors, such as the smell of organic acids, amines, aldehydes, or seawater.

Crabs and flies are arthropods. Like many other life forms, they made a transition from water to land life in ancient times. The ancestors of the family of terrestrial hermit crabs (Coenobitidae) probably took this step about 20 million years ago. Today, hermit crabs live their entire lives on land, except for the larval stage.  Exploring the molecular biology of olfaction in land crabs and flies thus allows insights into the evolution of the olfactory sense during the transition from life in water to life on land. (Proc. R. Soc. B, June 2012)

“The land hermit crab Coenobita clypeatus is an ideal study object to answer this question,” says Bill Hansson, director of the Department of Evolutionary Neuroethology at the Max Planck Institute for Chemical Ecology in Jena, Germany. The animals live in humid regions close to the sea and regularly visit water sources. Females release the larvae into the sea, where they grow into young crabs. These young crabs look for empty snail shells and live on land. They eat fruits and plants. This way of life suggests that the olfactory sense in crabs is still at an early stage of development.

In a series of experiments, Anna-Sara Krång, who worked on an EU-funded Marie Curie Project, tested 140 odor substances with different chemical properties, such as acids, aldehydes, amines, alcohols, esters, aromatic compounds, and ethers. She measured the excitation in the neurons of the crabs’ antennae in response to single substances. The results were so-called “electroantennograms” (EAGs) which measured tiny voltage changes across the cell membranes in the microvolt range.

The crabs’ behavioral responses to odorants were more obvious and much faster at a significantly increased humidity under the subsequently performed bioassays.  The EAG showed in fact a reaction at the neurons which was three to ten times stronger if active odors were applied at a higher humidity. In contrast, antennal neurons of vinegar flies did not show any differences and responded evenly and independently of the degree of humidity.

The analysis of the experiments revealed that hermit crabs responded primarily to water-soluble polar odorants, such as acids, aldehydes and amines, because their effect may be easily enhanced in humid air. These results suggest that crabs have so-called ionotropic receptors in their antennal neurons. Such receptors were found in other crustaceans, such as water fleas (Daphnia pulex) or lobsters (Homarus americanus). In the water flea genome, no genetic information was actually found for so-called olfactory receptors, which are responsible for the highly sensitive olfactory system in insects, such as vinegar flies. Although the receptor genes which are present in the hermit crab genome have not been elucidated yet, the scientists assume that olfaction in crabs is mediated by the original, evolutionarily older ionotropic receptors. It is generally believed that the ancestors of many insect species made the transition from the seas to the continents during much earlier geological eras and that insects have adapted their olfactory system to life on land very well. Terrestrial crustaceans, on the other hand, may be able to use their sense of smell on land thanks to basic molecular “equipment”, but their olfaction is still quite underdeveloped in comparison to insects. Therefore hermit crabs usually stay near the coast: not only because of the short way back to the sea where they reproduce, but also because of their limited sense of smell which does not allow them to orient themselves without any problems in the dry air of the heartlands.

Original article:

Anna-Sara Krång, Markus Knaden, Kathrin Steck, Bill S. Hansson: Transition from sea to land: olfactory function and constraints in the terrestrial hermit crab Coenobita clypeatus. Proceedings of the Royal Society B, June 6, 2012, online first. Doi: 10.1098/rspb.2012.0596.

Sizzling summer BBQ Safety

You’re sitting in your backyard, relaxing, as the smoky fragrance of burgers wafts over the fence you’re your neighbors.  Suddenly you get the idea to throw your own BBQ that will have your friends salivating for months to come.  After all summer is all about warm weather, fun times outdoors with friends and what better way to enjoy the short season by inviting your friends for a back yard cook out.  Before you grab your royal tongs and chef’s hat you go through your checklist: plates, cups, cutlery, salad bowls, ice bucket (and beer), napkins, meat, vegetables, and of course you’re Broil King.

Forgetting to buy burger buns or ruining a piece of meat isn’t the only thing you need to worry about.  Grilling can pose a real cancer risk at high temperatures; choosing what you grill and how you do it can keep you safe.  When you grill poultry, seafood or red meat the amino acids from the muscle proteins react with creatine under high heat forming heterocyclic amines (HCAs).  HCAs have been linked to cancers of the colon and stomach.   Furthermore the smoke that rises from burning coals and drips of fat that causes flare-ups deposit polycyclic aromatic hydrocarbons (PAHs) on the outside of the meat.  No fear, there is no need to give up on the barbecued foods this summer.  Here are some tips to keep you and your guest’s safe while still throwing an excellent BBQ.

  • Keep your grill clean to prevent grease fires and flare ups
  • Cook at lower temperatures

If you still want to grill turn the gas down or wait for the charcoal to become low-burning embers.  You can also raise the grilling surface from the heat source to reduce the amount of black char –another carcinogen- that can form on meat.  By flipping the meat every minute and marinating you can decrease HCA formation by up to 96% percent.

  • Don’t overcook your meat!

Of course you want to make sure your meat is thoroughly cooked, you don’t want any guests getting food poisoning.  However, cooking your meat past that point leads to higher levels of HCAs.  A high consumption of well-done meat is linked to two to five times more colon cancer and two to three times higher breast cancer risk.

  • Cook smaller pieces If you still want to eat red meat, make kabobs, they cook quicker and at lower temperatures.
  • Choose leaner meat: less fat should reduce flames and smoke
  • Marinate meat for a minimum of 10 minutes before grilling
  • Precook your meat in the microwave: For meats that require a longer cooking time you can precook for 2 minutes in microwave, drain the juices, and finish on the BBQ; this can decrease HCAs by as much as 90%.
  • Try fish, chicken or veggies

Another way to reduce your cancer risk is to change what you grill.  Fish and chicken both taste great and have lower levels of HCAs than red meat.  The American Institute for Cancer Research recommends limiting red meat to no more than 3Oz. a day.  By far the best choice for grilling is fruits and vegetables because they don’t form HCAs.  By making vegetables, fruits, whole grains and beans the centerpiece of the meal you will be consuming a healthy dose of phytochemicals which has been shown to stimulate enzymes that convert HCAs to inactive forms easily eliminated from the body.

  • Always keep your face away from the open grill and stand upwind if possible

You can lower the risk of exposure to PAHs by exhausted air by limiting your exposure to smoke.  Keep the lid down whenever possible and keep your face away from rising smoke.

Marine Protected Areas Not Effective Against Climate Change

While Marine Protected Areas (MPAs) are an important tool for conservation and protection of reefs they may not be enough to hedge against climate change according to research published in the journal Global Change Biology.

MPAs have been praised for their ability to mitigate stressors like nutrient enrichment, sedimentation, and overfishing.  MPAs offer zones of suppressed physiological stress protecting resilient key source populations and providing a healthy source of recruits to already degraded populations.  The success coral reef MPAs have had for restoring fisheries and trophic structures led to optimism that they would be useful tools for conservation in the face of climate change.

Warming global sea temperatures pose a serious risk to thermally sensitive ecosystems like coral reefs.  High temperatures have been correlated with slow coral growth, increased prevalence of diseases, and mortality from coral bleaching.  Reef-building corals already live near their upper thermal limits so if warming continues at a similar rate most coral taxa would be at risk of exceeding their upper limit in 100 years.

The authors tested whether or not MPAs mitigate temperature-associated coral loss and whether MPA design factors promoted resilience. They compared the effect of temperature on coral cover from 298 tropical MPAs (37 ͦN – 37 ͦS) to adjacent unprotected areas using a 21-year dataset.

The study found that MPAs fail to protect against thermal stress; despite the reduction of various physiological stressors resilience to thermal stress does not increase.  When water temperatures are optimal tropical MPAs lead to an average increase of coral cover of 1-2% per year.  Unfortunately, the benefits of MPAs are only realized after 4-14 years of protection.  This questions the efficacy of creating new MPAs in regions of medium to high susceptibility if warming continues at its current rate.

The authors offer two suggestions to MPA managers hoping to protect reefs against climate change.  First is to focus conservation efforts on protecting reefs with a history of moderate temperature variability because they are more resilient and acclimated to thermal stress.  Second, is to design MPAs on a larger scale.  Managers should design MPAs to be larger than an acceptable percentage of anomaly events so that it is guaranteed to contain unaffected populations within their boundaries.

When faced with the current climate changes crisis the local conservation measure of creating MPAs is not suitable to improve a reef’s resilience to globally increasing thermal levels.  The study suggests that effectively managing coral reef systems will require complementing local measures with global measures aimed at reducing anthropogenic activities responsible for climate change.