Tag Archives: biology

Bill Nye the Science Guy meets Vin Can the Science Man

OK, so I need to work on my stage name.

Back in May 2017, I tweeted at Bill Nye:

And it turns out that Bill, and the great writers and producers and everyone else behind Bill Nye Saves the World, were paying attention. Shortly after the tweet I was contacted by a producer of the show and asked if I would like to come on and give a demonstration about the evolution of “super-bugs”, i.e. antibiotic-resistant bacteria.

An opportunity for science outreach involving Bill Nye? Yes, please.

In this post, I first want to talk about the science in my 5 minutes (at the end of Season 2 Episode 3 of Bill Nye Saves the World). Then, I’ll touch on the experience of being on the show.

The Science

I wanted to convey three things in my demo:

  1. Antibiotics work really well!
  2. So does natural selection. In the presence of an antibiotic, bacteria resistant to that antibiotic survive and proliferate more than non-resistant bacteria, leading to the spread of the information conferring that resistance (i.e. the evolution of “super-bugs”).
  3. And that’s why it is important to be judicious about antibiotic use.

all while conveying how scientists can use models of reality to study biology.

So, for my demo I created a model of the evolutionary dynamics of bacterial strains within a person. In this model, bacteria either replicate or die—similar to a common mathematical model used to study evolutionary dynamics called a “birth-death process”. If there is more birth than death, the bacteria grow too big and overflow from the host—the infection spreads to other hosts. If there is more death than birth (as in a typical situation where the immune system does a good job), the bacteria die off —the infection is cleared.

What makes this a model of evolution is that we can introduce two different bacterial strains into the model and observe how the relative abundance of these two strains change within the total bacterial population over time. Let’s say one strain has a mutation in their genome that makes them resistant to antibiotics, and the other strain is still susceptible to antibiotics.

Let’s also assume that the host’s immune system is compromised, all strains are growing more than they are dying. The person goes to their physician, and gets some antibiotics that decrease the birth rate of only the susceptible strain. Growth of the susceptible strain is stopped, but the resistant strain grows and grows, and when the model “overflows” it is the resistant strain that spreads to other hosts.

By continually providing selective pressures favoring resistance, we drive susceptible strains to extinction. As the model suggests, we would expect the spread of antibiotic resistant bacteria to be especially prevalent in areas that have a high concentration of individuals with compromised immune systems that take antibiotics, such as hospitals and nursing homes.

But, there is hope! Many of the mechanisms of resistance are actually costly to bacteria when antibiotics are not present. It may be possible to reverse many of the mechanisms of resistance (select for non-resistant strains) by being extremely judicious about when to apply antibiotics. The original focus of the demo was on how to reverse resistance through exploiting this cost of resistance, however due to time constraints I refocused on the emergence of resistance.

My Experience

Everything was awesome. I had no idea just how much went on behind the scenes to get a show produced. From the props people helping with my demo, to the writers and producers working around the clock anticipating every little thing that will happen. Everyone really cared about being true to the science and explaining the information in an accessible and exciting way. Especially Bill Nye, who was extremely genuine and kind throughout the whole experience. I’m very grateful for the opportunity to help #savetheworld!




For those who arrived at my blog curious about my current research: I use mathematical models and simulations to investigate how tumors evolve from our tissues, how evolution has structured our tissues to minimize the risk of cancer, the effects of mutations in growing tumors, and how cancers evolve resistance to chemotherapy. Relating to pathogen evolution, during graduate school, I was part of a team that used mathematical models to study the evolutionary dynamics of pathogens and their hosts.


How much energy is in a thought?

Sometime during the last months of grad school I was in the office late, polishing off one too many coffees, and dipping into my emergency ramen noodle stores. I was searching for that elusive (and perhaps illusory) moment of clarity that, one hopes, arrives to propel a manuscript forward. But, the long hours and coffee caused my mind to wander into distant realms of science. I had just finished teaching about neurons and action potentials and brain activity in my physiology class (100 billion neurons, forming 100 trillion neural connections—more connections than stars in our galaxy—sparking up right now allowing you to think this!) and I had a cool thought:

I am converting these cheap noodles directly into science and new insight. I am a biochemical machine that converts packs of 10 cent fake noodles into knowledge.

And then, the natural follow-up: at what rate? What is the cost of a thought? How many noodles does my brain burn to construct a statement? A paper? A dissertation?

Now that I do not have a dissertation submission deadline looming, I have some time to explore these thoughts—thankfully while burning some higher-grade fuel than emergency ramen! Warning: the calculations that follow are extremely ‘back of the envelope,’ and should be taken with a heaping helping of salt and skepticism. This is just a fun exploration.

How much energy is burned in a thought?

First, let’s gather some parameters. How much energy does the brain use? The short answer is: an incredible amount. Despite only accounting for 2% of the body’s weight, the brain uses 20% of the body’s energy (that figure is for an adult, in newborns it is 44%!!) The brain uses 2–3 times the amount of energy that the heart uses.

[Aside: the brain is extremely efficient at what it does—processing information using orders of magnitude less energy than the best supercomputers.]

So, let’s say that the brain uses 20% of the body’s basal metabolic rate, and the basal metabolic rate is 1500 kcal/day. That means the brain uses about 300 kcal/day, or 0.0035 kcal/second.

The next question is: what is a thought? How much time does one take, and what proportion of the brain’s energy is devoted to “thinking”? I don’t know! But, does anyone know? I don’t know that either. Since it is my blog, I am at liberty to define a thought. Let’s say, for the sake of argument (and feel free to argue in the comments) 100% of the brain’s energy is required for “a thought,” and all thoughts are created equal. And let’s also say that a thought is a statement, and that it takes as much time as one would take to think or read a sentence. For instance, here is a thought:

“Wow, I am thinking this thought about thinking; this is one of the things that hydrogen atoms do given 13.82 billion years of cosmic evolution, and it’s super cool.”

How long did it take to think that specific (extended) thought?  More than a couple of seconds, less than 10? Let’s say a substantial thought takes 5 seconds. At 0.0035 kcal/second, that’s about 0.02 kcal/thought!

So, how many ramen noodles are burned for a thought? At 400 kcal per block, and 150 noodles per block, we have 2.67 kcal per noodle. Assuming the average noodle is 33 cm long, we find that there are 0.08 kcal/cm of noodle—and every thought burns about 0.25 cm of ramen noodle! Your brain is incredibly efficient—no wonder that future AI are always super jealous and vindictive in sci-fi movies.

Now we can readily convert thinking-time into calories, and content creators can register their influence in energy. For instance, if 100 people read this blog post, consuming 5 minutes of calories thinking through the content, then about 100 calories would be burned on my words. 400 people and an entire block of ramen has been consumed by my words.

I wonder how much ramen has been burned by Shakespeare?

My spot, your spot.

I grew up on an island with seven million other people. Let’s just say it was difficult to find a spot to call your own. One day, as a youngin’ exploring the world on my bike, I broke off a path that ran along Sunrise highway and continued on down a hiking trail that snaked along a waterway in the local state park. I eventually came to a small clearing, sat down, and heard the weirdest thing. Nobody. No cars, no lawnmowers, no people. Just the birds and the chipmunks and the occasional splash of a fish.


I felt as if I had stumbled on secret treasure. I spent a lot of time at this spot over my formative years, reading and thinking and being alone with my little patch of Long Island wilderness.

Before I left town for college I carved a “V” into the tree next to the water and said goodbye. While at college, I decided to major in biology, a decision shaped by my time out in the woods watching nature. I even wrote an essay about this spot for my freshmen writing class.

That biology major took on a life of its own, turning into an adventure through states, labs, and disciplines, and eventually resulting in a PhD from a zoology department and a dissertation on cancer and aging.
Last weekend Begum and I were visiting my parents and we decided to go for a quick hike before the ferry back to CT. A rush of memories came back, and I ran along this trail explaining my spot to her. She eventually found the V for me.


Both of these images are from June 2017

It was the first time in over a decade that I set foot in this clearing. Needless to say, it was a powerful experience, and it sparked a bout of retrospection that, thankfully, I have been happy to ride.
I said a thank you, and another goodbye, and we ran to catch our ferry.

This summer, I hope you go out and explore, and find your own spot.

Dragonflies are awesome.

Alright, so my wife and I both think dragonflies are really cool. We never really thought about exactly why we think this, it’s just this inherent neatness about them. Maybe it’s how they hover like brightly colored silent helicopters and then quickly dart about like… I don’t know, some sort of alien spacecraft. And, unlike some of our other backyard insect friends (I’m talking about mosquitoes and red imported fire ants, both of which seem to have an affinity for my skin in particular), dragonflies don’t bother us.

This last weekend I was fortunate enough to have a dragonfly interaction that got me falling down the wikipedia rabbit hole learning about our flying friends, so I figured I’d share some of what I found here. First, for the fateful interaction:

I was grilling up a batch of beer in preparation for the summer…

You read that right. Cannataro’s Brewery Summer Saison will go on tap June 2015.

… and I was joined by a male blue dasher!


He hung out for a while, flew to different perches, and even let me get a few close-ups.


Smiling for the camera. Which, by the way, was just my cell phone (galaxy s4).

Eventually my wort was ready to start cooling and he was done patrolling the garden so we exchanged our goodbyes and went our separate ways.  Little did I know the carnage that was awaiting me the next morning. Warning, dear reader, the next image is graphic.


My dragonfly friend had been decapitated! By one of his own! Well, kind of. That new, green, living dragonfly is (I believe) a female eastern pondhawk. After I took that picture she flew off, taking the body with her, leaving just his head as evidence. Woah. Talk about cool backyard biology! Down the wikipedia rabbit hole I went. Time for some rapid fire fun dragonfly facts.

Dragonflies have been on Earth in pretty much their present form for over 300 million years. In fact, the largest insect to ever exist was an ancient dragonfly (with an estimated wingspan of 28 inches!). They can spend years in their underwater nymph form, which has extending and retractile lower jaws (remind you of any alien characters?) and can feed on vertebrates (small fish, tadpoles) and mosquito larvae (thank you).

The adults enjoy mosquitoes as well (told you they were awesome).

The nymph crawls out of the water and transforms directly into the adult in a process called ecdysis. They have a unique mating system where the male grabs the female behind her head with the claspers at the end of his abdomen and they form a heart-shaped mating pair. Their wings are self-cleaning and water repellant due to the lotus effect. I can go on and on, but if you want to learn more you should check out this video:

So next time you look at a dragonfly think about how you’re looking at the 300 million year old body plan of a ruthless killing machine with a 95% hunting success rate. Dragonflies are awesome!


January 2015 fun facts

Woah, I’m way backlogged on blog posts! Don’t worry, I have some cool stuff in the works and I’ll share soon. In the meantime check out some of the science I’ve been starting my classes off with this month.

Aging research: blood to blood – scientists can splice animals together by creating a wound in each animal and sewing them together- their natural wound healing mechanisms join their bodies and their blood (it’s called parabiosis)! If you splice an old animal to a young one the tissue in the old animal gets “rejuvenated” by the young animal’s blood.  Sounds like the premise for a horror movie.

Scientists have discovered a new antibiotic that kills pathogens without detectable resistance.

Scientists have discovered that tumor cells can actually acquire previously lost DNA (in this case mitochondrial) from “normal” cells, and that the newly acquired DNA restores missing function. Think about that. Somatic cells (or cells that were once deemed somatic but now have become tumor cells) can horizontally transfer DNA. Biology textbooks get rewritten every day.

And, of course, I can’t introduce metabolic scaling and not discuss the invariance of heartbeats.


Mind controlling parasites- how sci-fi are zombies anyway?


Halloween weekend is drawing to a close, and as I type this (looking out a coffee shop window) I can still see the zombie makeup on the faces of those passing by. It’s understandable why the whole zombie thing can be pretty terrifying. In the movies the protagonist usually watches their once fully autonomous friends and loved ones fall prey to some microscopic parasite and become a mindless vessel, obeying the will of their neural captors, tasked with ensuring the survival of the parasite and oblivious to their own health. Good thing it’s science fiction! Right? Well, anyone studying parasitology can tell you that in some cases it’s less fiction and more science.

Whenever I teach the lab on species interaction I always spend a good bit of time on mind controlling parasites. First off- they’re just cool. Plus, there’s a lot of captivating videos out there! One of my favorite being:

(p.s. larva emerging from a caterpillar body below, viewer discretion advised!)

Great music and sound effects aside, it’s always interesting and sort of mind-blowing to see the caterpillar actively defend the larva that just busted through its skin. It really gives you a sense of just how possessed an organism can become at the whim of a parasite. Another zombie-state-inducing parasite infects snails:

And another favorite, the inspiration for the zombie-survival game The Last of Us, infects and alters the behavior of entire forests full of insects:


Ok, so mind controlling parasites might actually be all around us, but at least they only infect invertebrates. Right?! Well, no.

Rats have a natural (and understandable) aversion to cats. When they smell cat urine they feel fear and head in the other direction. However, rats infected with the protozoan Toxoplasma gondii, which only reproduces in the cat intestine, are actually drawn to cat urine. The parasite hijacks the sexual arousal pathway in the rat brain, and instead of feeling fear the rat feels sexual attraction to the cat odor. So, just like the snails in the video above, the rats search out their natural predators for the benefit of their parasite.


Ok, so mind controlling parasites can infect and manipulate the behavior of mammals as well. But, certainly humans, with their giant and complex brains, don’t have to worry about being influenced and controlled by the whims of a tiny microscopic organism. Right?! Well…

I have a habit of bringing up the universe that exists within multicellular organisms. It’s easy to think of this as a one way interaction- a large organism goes about their business and the little organisms tag along for the ride. But the survival and wellbeing of the microbiome is extremely important- so important that hosts even synthesize food for their microbiome during periods of illness to ensure that their microbial friends stay happy.

Is it possible that some of our microbial friends could be manipulating our behavior for their benefit? Some scientists have recently suggested that might be the case- we might be at the whims of a microbial puppet master. More research is needed to test these hypotheses, but I look forward to the day where taking a microbe-filled pill can change my appetite for the better and bolster my microbiome.

Outside of our bacterial microbiome, we also house a vast virome. Research published in PNAS this week has shown that humans can be infected with an algal virus, and this virus was associated with a 10% decrease in performance on visual processing exams. Additionally, mice infected with the virus took about 10% longer to navigate a maze and explored 20% less.

So, maybe we’re not so autonomous after all. Spooky! Happy Halloween!

Will the real Banana Spider please stand up?

I’ve encountered two different species of giant (subjective classification based on my previous New-York-State-only spider exposure) orb weaver spiders while living in Gainesville (and one non-orb weaver!). Both of which have been referred to as a ‘banana spider’. So, who are these spiders anyway, and which one is really the true banana spider?


Exhibit A- picture taken at the La Chua trail.


Exhibit B- picture taken in my front yard. (notice the flash reflection in the front eyes!)

It turns out that there are a few spiders referred to as a banana spider. However, only one of those spiders is pictured above, and it’s Exhibit B- the Golden Orb-Weaver (Nephila clavipes). Exhibit A, with its characteristic zigzag web, is commonly referred to as the Yellow Garden Spider (Argiope aurantia).

Apparently the Golden Orb-Weaver was recently moved out of the Orb-Weaver family and placed in the Nephilidae family because their webs weren’t sophisticated enough. Bummer!

Regardless of species name and web sophistication, if there’s one thing I’ve learned while living in Florida, it’s watch where you walk…


Banana spider waiting to catch a low flying plane