The lab is currently busy with a variety of field and lab-based projects. In April/May, Cam, David, Tom, and I were in Alabama collecting lizards. Here’s a glimpse of what the long trip to the South, and our work there, looks like! Check back later in the summer for more on the continuation of this project.
Hello again everyone!
While most of my work has been on measuring hormones and metabolites from blood, or recording behaviors, I decided to try my hand at something new. I wanted to see if I could measure the contents of a lizard egg!
As eggs can vary widely in the volume of water they contain, the first thing I had to do was dry the egg. Because I wanted to measure proteins and lipids, I wasn’t able to heat the egg up though, so instead I used a freeze-dryer. Once dried, I carefully removed the shell (because shells are reaaaaally hard to grind) and then homogenized the yolk sample.
Once the yolk was ground up, I needed a way to extract the proteins and lipids from the yolk. To do so, I weighed out a specific amount of the egg, added some dangerous chemicals, and then filtered that solution through an incredibly tiny filter. The size of the holes in a coffee filter are 20 microns, while the size of a bacteria is 0.6 microns. This filter had holes that were 0.2 microns!
After filtering the solution, I could then try to measure the amount of proteins and lipids. To do so, I added a tiny drop of the solution to a piece of quick dry paper.
Once the paper completely dried, I was able to shine a light through it and get an absorbance value.
Stay tuned for the results of what I found!
Hello, my name is Heather Engler. I have been working as a research assistant in the Langkilde lab since May 2016. And yet my background is not in biology. Instead, I have a B.S. degree in Accounting from Murray State University. So how did I wind up going from business to biology?
I began dating Dustin Owen, my boyfriend, while he was at Austin Peay State University. I was fascinated with his reptile research because I have always enjoyed learning about animals. So I naturally took an interest in his new eastern fence lizard research here at Penn State. I was really lucky that Tracy Langkilde didn’t mind me spending time with Dustin in her lab. I got to learn about all sorts of things from various lab members.
Last summer, Dustin and some of his new lab mates caught lots of eastern fence lizards to be used in their research projects. They were busy with their research, so they needed someone else to take care of the lizards on a daily basis. Since I had not landed an accounting job, Dustin put in a good word for me with Tracy. Luckily, she was willing to give me a chance.
I absolutely loved taking care of those lizards last summer! Some of the females became gravid, and I got to help collect the eggs after they finished laying them. After all of the females had laid their eggs, it was time to incubate them in the lab. One random day in July, I was checking on the eggs and noticed some tiny bodies. The first of the eggs had hatched! It was so cool because the hatchlings were so little compared to the adults. Since we were short staffed at the time, I got to help record the morphology data on the hatchlings. I even learned how to toe clip them. I had never done this kind of work before, so it was a fun learning experience.
Since I had done such a good job with the adults, Tracy let me also take care of the hatchlings. And it has been a blast watching over those lizards. It won’t be too much longer until they’re fully matured adults. I’m even getting to help on a side project concerning them. Braulio Assis, one of the current grad students in the lab, has been taking photos of the juvenile lizards at 9 week intervals. One of the things he wants to know is if testosterone levels are related to the size of male cloaca scales. I’m helping to answer this question by measuring the area of the male cloaca scales in the photographs of the male juveniles. I get to use this really cool software, called ImageJ, to trace around the scales in order to get the measurements.
If you had told me 5 years ago that I would go from working in the accounting department of an engineering firm to working in the lab of a world famous biologist, I wouldn’t have believed you. But here I am. I have moved from business to biology, and I couldn’t be happier.
[posted on behalf of Heather Engler]
The first year of my MSc will be coming to a close in May! After a semester of my first graduate school classes and my first experiences as a teaching assistant I was just starting to get the hang of it and the semester ended. This semester has been filled with research planning and manuscript writing. Just coming from my undergraduate degree, the thought of not taking any classes for an entire semester sounded insane, but so far, I have been very productive. I have one field season down, one coming up this spring, and one manuscript started.
Writing my first manuscript has been interesting to say the least. I have learned so much about statistical analysis of data, and the dreaded R. I am having a difficult time with the introduction section but the results and methods were a breeze. I look forward to getting back out into the field, that is why I got into this field after all.
My upcoming field season will begin sometime in March as the vernal pools begin to thaw and the wood frogs return to them to lay their eggs. I will be doing a transplant study that will follow up on research that I did in the lab for the first chapter of my thesis. I used a 3×3 full factorial design to look at how pH and UV-B affected developmental rates, mass, body condition, survival, and baseline and stressed CORT levels in wood frog tadpoles. The second chapter will take place within local vernal pools. Stay tuned for the results from the upcoming season!
A lot of my work in the lab involves assessing the health and well-being of our fence lizards under different conditions, including their parasite burdens. Parasite infestation can vary with immune status, stress, or external factors such as predation (for example, lizards in fire ant invaded areas have fewer ectoparasites). Ectoparasite (ticks, mites, etc.) load is easy to assess, as we count them on each lizard shortly after capture. Internal parasites are a bit trickier, but one method commonly used in veterinary medicine is to collect their feces, and check it for intestinal parasites and eggs.
The Langkilde lab has recently returned from its annual pilgrimage to the SICB (Society for Integrative and Comparative Biology) meeting, which this year was held in beautiful New Orleans! All our lab members presented talks, and had a great time networking, catching up on top research, and telling people about our own.
Below are some of our thoughts on the meeting, summaries of what we presented – and some tips for conference-goers from all fields!
“I talked about a paper I’ve been working on from our field season in Alabama last summer. Animals encounter environmental stressors daily; how does frequent, low-level stress influence survival and reproductive success? We show that, in Eastern fence lizards, a daily dose of low-concentration stress hormone led to increased adult mortality, and decreased hatching success of her eggs. This was the first conference I’ve been to where animal behaviour hasn’t been the primary focus – this reflects my broadening interests – I’m really excited by integrative research, so this meeting was a great way to see what other people are doing in more mechanistic fields (physiology, genetics, etc). It gave me lots of ideas for taking my own work forward!
My top conference tips are to contact people in advance that you want to talk to – that way you’ll be less likely to chicken out of approaching them! And – make use of Twitter before, during, and after the conference. It’s a great, informal networking tool. I met up with loads of top researchers that I’d first contacted on Twitter, and made lots of new friends!”
“I presented on the impact of a stress treatment on maternal behavior and offspring physiology and morphology. The thing I enjoyed the most was getting to meet not only senior researchers but also new researchers and hearing both of their perspectives.
My tip is to go to the socials and groups at night. They are fantastic places to talk with and meet people.”
“We already know fire ants are an invasive predator to many organisms, including fence lizards. What I want to focus on is the interaction of Fence Lizards and Fire ants, but as a prey source. This is the first step in my research, by using this study system, to understand how native species adapt to invasive species. The academic side of me really enjoyed meeting other scientist and just chitchatting in informal ways. The 24 year old side of me loved the location of SICB, considering it was in New Orleans!
Tips for conferences: Well this was my very first conference and I was worried about how to interact with so many bright and accomplished minds. The best and most cliché bit of advice I have, is simply be you. There is no point in putting on a different face, if you’re not even comfortable in it.”
“The water chemistry of vernal pools are often impacted by the environment. Changes in the pH and UVB impact the larval amphibians that live there. But how? Stay tuned for an upcoming publication! I LOVED meeting new people. I especially enjoyed meeting people who are working outside of my field of study. Their perspectives on my work are often very different than those within my field and I learn a lot from them.
My advice: TALK TO EVERYONE! You never know who you will meet. If you see a poster you don’t usually have an interest in, just stop and ask a question. If nothing else you may make a friend!”
“Going to SICB for the first time was fantastic, and New Orleans is a peculiar, very musical city, which I appreciated a lot. Being exposed to research from large variety of fields in biology certainly allowed me to appreciate other research areas better, so I definitely recommend attending talks that are out of your comfort zone. You never know what new ideas you might come up with!
Another valuable tip I have is, to never underestimate the power of a 25-minute nap during lunch break. The amount of information you receive over multiple days in a conference can be a bit overwhelming, so it’s important to rest whenever possible. It also helps you enjoy the nightlife better!”
Many of you would have played with Mexican Jumping Beans as a child. Ever wondered why it is that they jump? I presented some undergraduate-led research revealing what motivates this fascinating behavior.
Now that our field seasons are (mostly) over, the members of the Langkilde lab have been busy processing the blood samples we collected over the summer.
As I wrote last time, most of us are looking in some way at the impacts of environmental stressors on an animal’s behaviour, and the characteristics of the offspring they produce. In order to test these questions, we need to be able to quantifiably measure the stress levels of the animals we study.
To do this, we took blood samples from our study species in the field to measure levels of “stress hormones” (glucocorticoids, factors produced by the adrenal glands in response to stress). These hormones circulate in the blood, and correlate with the baseline stress levels of an individual – the more glucocorticoids we find in the blood, the more stressed an animal is. We determine the concentration of glucocorticoids in our blood samples by first centrifuging the sample to separate red blood cells from the plasma (the clear fluid in the eppendorf tube below), and then running the sample through an enzyme immunoassay.
Enzyme immunoassays work by using antibodies that bind to the factor of interest in a sample – in our case, the steroid hormone corticosterone. We add a known amount of plasma to each well of the plate (above right), and in each well, the corticosterone in the sample binds to the antibodies. The antibodies that aren’t bound by corticosterone are bound by a conjugate tracer, which gives off a colour. So, in the plate above, the more “yellow” the well appears, the less hormone it contains (meaning that more free antibody sites have been left to bind with the yellow tracer-bearing conjugate). We can compare the “yellowness” of each well with wells containing a known amount of hormone, and this allows us to calculate the concentration of hormone in each sample:
I’ve had a lot of fun learning these techniques this Fall, processing my lizard samples, and helping Chris process some of his rattlesnake samples! I’m looking forward to reporting back on the exciting results these data contribute to over the next few months.