The Germ Guy: Confessions of a Mercurial Microbiologist



Ivanka Trump And A Different MAGA (Mosquitoes Ain’t Gonna Attack)

I don’t know anyone who actually enjoys getting bit by a mosquito. The only exception might be…

(Mosquito Researchers…)

The bites themselves are bad enough with the welts and incessant itching. But when you take into account the potential for disease transmission, a mosquito meal may present more than a mere annoyance. The list of potential infections is getting longer and the impact of these agents on human health is well…


There’s one sure way to avoid an infection…don’t get bit. That’s why media stories on mosquitoes and health usually include advice such as wearing long clothing, avoiding prime mosquito meal times, and of course, using a repellent, such as N,N-Diethyl-m-toluamide, which is better known as…


How DEET works is pretty fascinating. It’s a chemical that gives off a particular odour that repels mosquitoes. The mechanism behind this action took quite some time to figure out but as always, scientists were on the case and eventually figured it out.

Much like humans have the olfactory system, which allows us to detect smells and determine whether we like them or not, mosquitoes have a similar mechanism to recognize molecules in the air. It looks something like this…

(Feel itchy yet?)

That ORN is known as an olfactory receptor neuron and it possesses a number of different proteins capable of recognizing various molecules in the air called odorant receptors. Somewhere within those neurons is a receptor that tells the mosquito to veer away when DEET is around.

Unfortunately, no one knew which one receptor was responsible. This made attempts to study this process any further difficult at best. Then in 2014, a team of researchers examined those odorant receptors and figured out which one detected DEET.  They published the finding in the paper, “Mosquito odorant receptor for DEET and methyl jasmonate,” which you can click on to read.

The receptor is called CquiOR136, which stands for Culex quinquefasciatus Odorant Receptor 136. It’s not a fancy name but the team makes up for this apparent lack of creativity with a cool sense of…


The data reveals CquiOR136, upon sensing DEET, or another molecule known as methyl jasmonate, sends a message to the mosquito’s brain that the environment is threatening and that it’s best to move on to other places. If that area happens to be your skin, you are saved from a bite.

This discovery allowed us to develop a new definition for the now common acronym, MAGA. Instead of Make America Great Again, however, these researchers have found the trick to ensure…

(“Mosquitoes Ain’t Gonna Attack.”)

After the discovery of CquiOR136, researchers tried to find other products capable of triggering that molecule and keeping mosquitoes away. Over the coming year, certain soaps and perfumes were found to repel mosquitoes. Some were even as good as DEET.

With this in mind, a team of Californian and Brazilian researchers decided it was worth looking at a specific perfume to see whether the product also could keep mosquitoes away.

The fragrance they settled on happened to be…

(You could say they were allured…)

Actually, we don’t know the answer as it was never mentioned in the paper. You can check for yourself by reading it here: Ingredients in Victoria’s Secret Bombshell and Ivanka Trump eaux de parfums that repel mosquitoes.

One could surmise, however, the choice was due to presence of an ingredient in the perfume. If you look at the title of the paper from the DEET researchers above, you’ll find a specific name, methyl jasmonate. As you might expect, it’s a molecule found in the jasmine plant, which is included in Ivanka’s fragrance description.

The team went searching to find something that looked like methyl jasmonate and they indeed found it. It was a little different in name – methyl dihydrojasmonate – but the group figured it may have the same effect on mosquitoes.

They performed the tests using another product already shown to repel the insects – Victoria Secret’s Bombshell – and observed whether the mosquitoes found the fragrance alluring or repulsive.

I’ll let the data speak for itself with this graph comparing DEET, Bombshell, and Ivanka’s perfume on how well skin was protected against bites…

(Pretty impressive…)

With this in mind, you might think about making the switch from DEET to Ivanka’s pink potion. But there is a slight issue one should consider. To get an equal level of protection as DEET, the same amount of perfume would have to be used as one would use with a repellent. This would probably mean changing the bottle top from the gentle, mist-forming, atomizer to well, this…

 (You get the point…)

In light of all the concerns we have these days with sensitivities to fragrances, it may not be all that great of an idea.  Not to mention, the cost of Ivanka’s fragrance is about US$30 a bottle. In comparison, that good old fashioned DEET spray will set you back less than $10.

While this study is obviously as much fun as it is science, there is a serious message. In light of the troubles mosquitoes can cause, you can never go wrong with keeping a good repellent around. It’s all about keeping true to MAGA – Mosquitoes Ain’t Gonna Attack.

Whether you go with the usual brands or take a chance on Trump, just be sure to have something to keep those mosquitoes away. Because unlike the other Trump MAGA, this one deals not with society, but your own health. In light of the risks associated with mosquitoes these days, you can never be too safe.


The Secret Behind Stress Eating And Obesity…

Mysteries are a staple in the entertainment business. Something nefarious has happened and it’s up to the hero to go through the clues and find the responsible suspect. Usually, when the answer is discovered, all the pieces are put together and eventually, the revelation is made…

(Usually with an all-knowing smirk…)

Mysteries are also a major part of scientific research. Large, scoping questions are asked and over years, clues are revealed through the tireless work of labs all over the world. It may take decades but eventually, the answer is found and the results are shared with the world.

Of course, there are times when the answer seems to be impossible to find. Researchers are left scouring through the data in the hopes of finding something that may open up a path to discovery. But more times than not, the results offer little direction allowing hope to be replaced with…


I’ve been there numerous times and one of the things I find is that when I get stressed, I tend to get hungry. Making the situation worse is that the pangs are not satiated by eating healthy food. I want something bad, fatty and sugary. It could be fish and chips, a fatty burger, or…

(A tart…)

This phenomenon, known as stress-eating, is quite common although how it happens has been, in itself, a mystery. For decades, researchers have been working with people and animal models in the hopes of finding the one mechanism – or if they are lucky the one cell type – responsible for this rather poor health choice.

Now, we may finally have an…

(Aha! moment…)

It comes in the form of a paper entitled, Microglial Inflammatory Signaling Orchestrates the Hypothalamic Immune Response to Dietary Excess and Mediates Obesity Susceptibility. You can click on the title to read the paper.

The researchers used mice to explore what happens inside the brain during what is known as diet-induced obesity. It is a well-known condition caused by a very familiar villain of health. I’m sure you’ll know it as soon as its name is revealed…

(Sorry, Moriarty…)

It’s inflammation.

When the body suffers from this ailment, immune cells drive other bodily systems to alter their function. This happens in the gut, in the blood, and yes, even in the brain. In the latter, the immune cells involved are known as…


They are the soldiers responsible for ensuring the brain is protected from infections, injury, and other invasions. These cells had been shown to be involved in increasing one’s appetite for unhealthy foods particularly when the body experiences stress.

But no one could quite figure out how or why…

The team focused on the area of the brain known to be responsible for the need to eat. It’s officially called the mediobasal hypothalamus, but is more commonly referred to as the MBH. To give you an idea of the size of this region…

(Here’s the hypothalamus…)


(And here is the MBH…)

The first experiments examined the concept of a loss of function. In other words, they reduced the cell’s population from this area and also prevented these cells from doing their jobs properly. As expected, both helped to reduce the urge to eat in the animals.

The next stage of the process required them to do the opposite and amp up the effects of the microglia. To do this, they created a hyper-inflammatory environment. When they did this, the mice had severe hunger issues.

These experiments were run of the mill neuroscience and little can be concluded from this information. But before you start wondering…

(When will he get to the good stuff?)

Let me tell you that we’re close to that Aha! moment.

When the microglia were hyperstimulated, something else happened. The mice became resistant to a particular chemical known to be involved in obesity and other weight-related issues. It’s called…


I know it doesn’t look like much but this little protein has a huge impact on our ability to control our weight. It helps to control how happy we are with the nutrients inside us.

But if we lose out on the ability to respond to leptin, a condition called resistance, a rather vicious cycle occurs. We tend to eat more sugary and fatty foods in order to feel full. But since we can’t sense that fullness, we continue to eat. Put it this way…

(Leptin resistance is bad…)

In this experiment, the researchers had caused leptin resistance by making the microglia hyperactive. In turn, this led to the initiation of the cycle, and the mice became obese.

Now you can say Aha! or perhaps even…


So, to recap:

  1. Stress changes the way microglia function in the brain including the MBH;
  2. They can get overexcited and become resistant to leptin;
  3. Leptin resistance can lead to changes in energy balance & reduce the sense of fullness;
  4. This leads to an urge to eat sugary foods;
  5. This in turn eventually can lead to weight gain.

The overall results of this study do help us to solve the mystery of stress-eating (at least in mice). But the information also introduces another more intriguing question…

(Can we prevent obesity?)

Although we won’t know this for quite some time, the clock may already be ticking in this direction. When the researchers took out the microglia, they used a drug called PLX5622. It’s being tested in clinical trials to manage arthritis. With these results in hand, the drug may be given further examination to see whether it may be able to help calm down the microglia and possibly control stress eating.

But that is for the future. In the meantime, when we feel stressed and find ourselves stricken with the munchies, just realize we may not to blame. Based on this study, it may be just our microglia forcing us to think and act this way. With more research, we may be able one day to find ways to reduce the stress we feel and reduce the chances for obesity.

In the meantime, if you want to avoid stress eating, the best way to achieve this may be to find at least a few moments during the day when you can exist is the state known to reduce the hunger…


The Unexpected Taste Of Pure, Pure Water…

In order to survive, almost all life forms require water to live. There are some exceptions, like bacterial spores, some worms, and the most fascinating creature of all…

(The Tardigrade!)

For humans, drinking water may seem to be a rather inert process. We drink, we become hydrated, and we’re good to go. But have you ever taken the time to notice the taste of water?

It may seem odd at first but when you think about it, every water source has a different effect on our tongues. In some circles, the taste of water can determine its quality. There are even, believe it or not…

(Water Sommeliers…)

The key to a good water lies in the content within. Salts, minerals, and other components all add to the flavour of that clear solution. Depending on the concentrations, your tongue will be greeted with a different sensation, which provides your brain with either pleasure or unhappiness.

But what about pure water? Would you think it has a taste?

I’ve tried it myself and I have to admit, I was shocked when I noticed my tongue reacting to the liquid combination of hydrogen and oxygen. Back then, I had no idea what was happening. But now it seems the mechanism behind that taste has been identified.

The answer comes to us in the form of an article entitled, The cellular mechanism for water detection in the mammalian taste system. If you click on the title, you should be directed to a free PDF. If not, I apologize.

The researchers set out to figure out how our tongues perceive the taste of water. As you might expect, they believed the answer lied in the taste buds. If you’ve never seen one at the molecular level, here’s what it looks like…

(Pretty, don’t you think?)

The key to taste is found on the surface of those cells wrapped up in the ball. They are called taste receptor cells, or TRCs. They can sense all five tastes – sweet, salty, sour, bitter, and umami – and relay that information to the brain.

The team decided to take a look at these cells and the molecules that determine the various tastes, aptly called taste receptors, in the hopes of finding any that would react to pure water. Eventually, they did. The TRCs responded the same way we respond to…


You’re probably wondering how something that is completely pure and devoid of any acids – or bases for that matter – might trigger an acid response. The researchers did too. The answer came in the form of another normal process we all perform but think very little about…


When we breathe out, we are sending out carbon dioxide into the air. But not all of it goes into the atmosphere. Some of the TRCs will actually grab on to the molecule and mix it with the water in our mouths. The end result is another product we all know quite well but don’t consider to be part of our bodies…


This natural base keeps the TRCs prepped for anything acidic that might be considered toxic or noxious. Many possible substances apply in this case although one I had hoped would fit into this category does not…

(But I digress…)

When pure water enters the taste bud area, a dilution effect occurs. The bicarbonate is removed from the area and the TRCs recognize this as the arrival of an acid.

Here’s where it gets interesting…

When the TRCs are triggered, we tend to want to drink more. It’s as if our brains want us to continue the dilution process. That makes sense as water does offer the chance to clear out mouths and reset the balance.

But this has no effect on our sensation of dehydration or the feeling of being full due to water. This is controlled by another system in the body related to stress. In other words, while these TRCs may help us drink a little more, they are not responsible for…

(You get the idea…)

With this in hand, here’s a little experiment for you to try.

When you next decide to take a sip of water, take a moment to decide if first you can taste it. Do you have a slightly acidic feeling on your tongue? If so, what does it bring to your mind?

Next, see if you can just have just that one sip alone. Do you need more right after? You may find yourself having to go back to the glass or bottle for some more dilution to feel happy.

Finally, when you are finished drinking the total volume, try to discern a taste. Is it different from when you took your first sip? Can you sense the dilution effect?

If you decide to perform the experiment, let me know and share the results in the comments.

Is Social Media Making You Depressed?

Based on all the hype over social media, most people may think logging on is the equivalent of saying…

(A world of opportunities…)

But last month, a study came out that suggests hopping on to the information highway may have a very different result. Instead of finding joy, the researchers suggest we may be making ourselves…

(You get the emoticon idea…)

The paper is entitled, The happiness paradox: your friends are happier than you and it appears in the journal, European Physical Journal Data Science. While the article is a great read, the overall outcome of this report reveals social media – or at least Twitter – is not a reflection of a democratic society. Rather, it is more like another environment all of us have encountered at one time or another…

(High School…)

Anyone who has walked these halls knows amid the goals of education, life learning, and of course, doing well on exams, there is another mission for many a student. We can call it striving interpersonal relationship success, seeking widespread esteem, or developing a cult of personality. But most people tend to call it…

(A Popularity Contest…)

Much like high school, if you are not popular on social media, then you may be ‘missing out’ on the events and activities others may be experiencing. You may also find a lack of interaction leads to a reduction in self-esteem and self-worth. If things get really bad, you may sink into a quasi-depressive state.

But this isn’t the worst of the situation. In high school, the interaction within the population lasts only about six hours a day and is interrupted by classes. On social media, this effect can be continuous. By seeing the experiences of other individuals and comparing them to yours, you may be amplifying the effect and worsening the potential for…

(Mental Health Concerns…)

From a social perspective, this paper probably makes quite a bit of sense. But mechanistically speaking, there is little information to help us understand why this effect happens.

Thankfully, the answer was found some seven years ago in a paper entitled, A Wandering Mind Is an Unhappy Mind, which was published in the journal, Science.

The study was simple in that the researchers contacted 2250 adults at random times and asked them a series of questions beginning with their state of happiness. With that in place, they asked about what the individual was doing at that moment, whether the mind was wandering, and if so, on what imagery.

When the results came back, the team discovered a wandering mind was in a way similar to what is commonly associated with idle hands…

 (They do the devil’s work…)

Almost half the people contacted were suffering from a wandering mind. When they were asked about the nature of the wandering, most were thinking of pleasant topics while only about a quarter were thinking of unpleasant situations. As one might expect, the latter group were not feeling altogether happy. But even those who were thinking of pleasing situations were also not any happier.

I admit, after I read this, I was probably thinking the same thing as you…

(It makes no sense…)

But when you think about it, those who were wandering to pleasant thoughts were trying to get away from an unpleasant reality. They were not happy to begin with and no amount of daydreaming would help.

As for those thinking unpleasant thoughts, it seemed to be a consequence of a lack of focused action. They were either bored or doing something that required little focus, such as watching television, doing errands, commuting, or trying to keep themselves busy by…

(I’m sure you guessed this already…)

This develops a vicious cycle in which a combination of a lack of focus and low popularity on social media lead a person down a rather unfortunate path of even more unpleasant thoughts.

The best way to avoid all this trouble is to give yourself the opportunity to get away from the contests and the lack of focus. This could come in the form of a good book, a compelling movie or television series, a hobby, skill, or exercise.

There’s also one other activity some may considering. It was found by the researchers in the second study to cause the least amount of mind wandering…

 (If you don’t get this, Google, “The Newlywed Game”)



Create a free website or blog at

Up ↑

%d bloggers like this: