The Roots of Research with Dr. David Weindorf
Join Georgia Southern's Vice President for Research and Economic Development, Dr. David Weindorf, as he sits with faculty to discuss all things research. Each episode, you'll get to know a faculty member, their work, and the roots of their research!
The Roots of Research with Dr. David Weindorf
Episode 1 - Dr. Stephen Greiman
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In this premiere episode of Roots of Research, Dr. David Weindorf sits down with biologist Dr. Stephen Greiman to explore the fascinating world of parasites and the global adventures behind his research. From Mongolia to Vietnam, Greiman shares how studying bats, snails, and microscopic symbionts reveals vital clues about emerging diseases and ecosystem health.
Welcome to the Roots of Research, where we go behind the scenes of research publications and dig deeper with Georgia Southern faculty. I'm your host, David Weindorf, and today I have the pleasure of speaking with Dr. Stephen Griman. Now, Dr. Griman is an associate professor of biology and has served as a Propost Faculty Research Fellow at Georgia Southern University. He received his PhD in biology from the University of North Dakota, was an NSF postdoctoral research fellow with the Museum of Southwestern Biology at the University of New Mexico, and his research explores ecology, evolution, and diversity of parasites and their symbions. His field works expand Mongolia, Vietnam, Panama, and beyond. He's published extensively on parasite systematics, microbiomes, and host parasite networks, contributing over 60 scientific papers and book chapters. Dr. Griman has also been recognized with awards such as the American Society of Parasitologists New Investigator Award and is currently a Fulbright Scholar Finalist, going to work on bat parasites in Vietnam. Beyond his research, he's deeply committed to mentoring students and advancing natural history collections as vital tools for understanding biodiversity. Congratulations, Stephen, and welcome to the show.
SPEAKER_01Yeah, thank you. I'm excited to be the inaugural guest.
SPEAKER_00Absolutely. We're excited to have you. So I'm going to start with this question. All right, our listeners want to know this. Every scientist has an origin story. What was the moment that sparked your passion for biology?
SPEAKER_01Yeah, so it's actually pretty crazy. I started out as an aviation major in yeah, in college at the University of North Dakota. They have like the top aviation school in the nation. So I went summer after my high school and then jumped right into private pilot school, got my private pilot's license. But it just didn't hit me as a passionate kind of career choice. And so I decided to switch, but at that point I was stuck in North Dakota because the semester was starting. So I was like, all right, I've always liked biology. I've always wanted to be a veterinarian, so I decided to switch over to biology. And then my sophomore year, I took an animal biology class from a professor who I ended up doing my PhD with, and he asked if anybody wanted to do research. So I volunteered. And then I started doing research in parasitology from sophomore year on through senior year. Decided to skip applying to veterinary school because I got a passion all of a sudden for parasites, and I just dove right into parasitology. And the crazy thing is, before that, I had no idea parasites existed. So the first time I heard about parasites and the diversity of them was really in that animal biology class that I took.
SPEAKER_00That is so amazing. What a fantastic story. And it brings us to where we are today, which is another amazing story in and of itself. You are getting ready in about two weeks to go to Vietnam. What made you choose Vietnam for your Fulbright and how do you see this experience shaping your research?
SPEAKER_01Yeah, I've been fortunate as a grad student and as a faculty member and postdoc to travel all over the world. And as a PhD student, I ended up going to Vietnam two times to work on near a quetsial symbionts, these bacteria that are transmitted by parasites that cause diseases in horse and bats and other wildlife, but also in humans in Southeast Asia. So it was a connection where we were trying to find the parasite host of the bacteria that infects humans. And so I dove right in, went to Vietnam twice, collected bats and snails and parasites from all of these different animals. And that kind of stuck with me with collaborating with individuals in Vietnam. So I continued to collaborate through my postdoc and through, you know, here at Georgia Southern. I published almost yearly with my colleagues in Vietnam. So it was really a perfect choice in my mind for a Fulbright because I had the network of colleagues and other researchers that could help me plan the research trips and find schools for me to teach in. So that's why I picked Vietnam and now kind of diving into it, it's really gonna, I think, kick off more of a longer-term collaborative relationship. It's already been 12 years since I've collaborated with them. But now kicking off maybe more of collaborative funding opportunities and really building the stronger preliminary data to look at bats and their parasites. But the cool thing about bats is right, they're super long-lived, so they're also bioaccumulators, and they can have PFAs and other kinds of chemicals that can cause illnesses in humans and cancers. Uh, so we can screen those for that. There's hantaviruses and other viruses that are transmitted by bats that I have collaborators in Japan, and we just published on a new hantavirus from Panama that we found in bats. And so there's this kind of wider connection that should branch out to even more international collaborators.
SPEAKER_00So the moniker you're gonna go by is Batman. I'm just I'm gonna just We have the Batman in studio today. That is fantastic. Now, one of the things that we are hearing more and more about these days in the news is this sort of vector-borne disease jumping from animals over into humans. Talk about how your research touches on that.
SPEAKER_01Yeah, so zoonotic pathogens are probably the biggest threat to human health out of all the potential kind of pathogenic pathogens or you know, RES human bacterial viral pathogens are parasites are most likely to come from wildlife as humans encroach on habitats or make contact with these. Um so it is a major contributor to what we want to do. Kind of the first thing you need to do when looking at potential for neglected tropical diseases that are zoonotic is to do biodiversity discovery. It seems like such a broad thing to go out and just collect bats and see what parasites are there and see what bat species are there. But if we don't do that biodiversity discovery first, they can't then screen those for other potential pathogens or you know look at vectors from transmitting from parasitic worms that I study. Um, but also we collect the endoparasites, so all the tick slice fleas, these crazy bat flies that kind of look like weird spider, like animals that live on the bats. And we collect all of that and we put them in museums, and then that allows other researchers that study the viruses or the bacteria to be able to then utilize these collections to really expand their usefulness. And so that's kind of you know, even though I directly might not screen them for pathogens, they hopefully will be used by other researchers.
SPEAKER_00Absolutely. Wow, that is just incredible. Really incredible. You know, you're getting ready to go to Vietnam, but you've also conducted extensive research in Mongolia, spending some summers there in the field. Talk a little bit about those experiences and how that might be different from your Vietnam experience that you're getting ready to, the research you're getting ready to conduct.
SPEAKER_01Yeah, so Mongolia has been amazing. I started working there when I was a postdoc. So I went two times, once in 2015 and once in 2016 as a postdoc. And that also was kind of biodiversity discovery research. So there was an NSF grant at the University of New Mexico, um, as well as other colleagues at different institutions, that was really looking at mammals and their parasites across Beringia, which is the land bridge that connected North America to the old world. And a lot of animals came over and brought with them their parasites and went back, and then when ice ages you know melted or the ice caps melted, then that land bridge went away. So they were really trying to document what species are on either side and look at kind of the evolution of these organisms over time. Did they come from the old world into the new world or back and forth? And did they bring their parasites with them or you know, obtain those parasites when they colonize a new area? So I was lucky to go on those trips and we collected a lot of mammals and parasites, and really we collect, you know, over a thousand animals every time, and we're camping in new spots, and we travel and we camp at a site for three to five days and then drive to a new site. So just seeing the whole country of Mongolia. And that expanded into as a researcher here at Georgia Southern, where we obtained an NSF collaborative grant with the University of New Mexico, University of North Carolina, Greensboro, us here at Georgia Southern, myself, um, Northern Michigan University. And so that also was kind of a continuance of looking at mammals and their parasites, but then looking at how ecological change is contributing to changes in the populations of these parasites and mammals. As China's building what's called the Silk Road Initiative, where they're building kind of the second Silk Road, which is called the Belton Road Initiative. And so through that, we want to look at how that infrastructure change in Mongolia, which used to be pretty wide open and very nomadic, and now is lots of paved roads, where in 2015 and 16 there was like two paved roads in the whole country. When we started going back in 2022, they now have a huge network of these roads and railroads and their coal mining and gold mining. So we really want to look at the changes in the parasite and mammal community that's been contributed from that major land use change.
SPEAKER_00Well, and it's so fascinating for me to hear about you talk about the land bridge from the old world to the new world and you know how that has direct implications with parasitology. I hadn't even thought about that before. I mean, really, that's uh that's amazing to think about that stuff just migrating around the world.
SPEAKER_01So yeah, you had these major refugias where the ice wasn't present, and so a lot of mammals and other animals kind of congregated in that area, and you ended up having this rapid diversification of parasites as the ice sheets retracted. Uh, and so yeah, we're seeing huge differences in parasite communities and huge increases in diversity in the new world, as well as the old world still has a lot, but you don't see the same parasites that you see in the old world as the new world.
SPEAKER_00Wow, that is incredible. Incredible. All right, so you've had all these international experiences. You've been in Mongolia, you're getting ready to go to Vietnam, you've been in other places around the world. How have these experiences influenced how you mentor students right here at Georgia Southern? And also you mentioned a little bit about the collaboration that you bring back home. Talk about how that is also having an impact on your students here.
SPEAKER_01Yeah, so I've been fortunate on some of the trips to Mongolia. We always bring students with us. So I've had a master's student from Georgia Southern join on one of those trips. We have lots of Mongolian students that join along, both undergraduate and graduate. Uh, there's a few Mongolian students that have moved to some of the labs of my collaborators to do their master's degrees and their PhD degrees. And so not only just institutional but global, we try to increase the training involved in kind of biodiversity discovery, parasitology, mammalogy, virology, bacteriology, kind of combining all these different fields because we end up collecting holistically these animals. So when we get a small mammal, we collect it, the mammologists take tissues, we have liquid nitrogen tanks with us, so they're all frozen in liquid nitrogen. Uh, lung, liver, kidney, spleen measurements are taken. Animals are either museum skins made or placed into ethanol whole, or they're skinned, and then the skeleton is dried and given to domestic beetles where you get all the bones. So all that's maintained in the collection for you know other studies, and then we get all the ecto and endoparasites. So we try to train these students in this kind of holistic sampling so they understand the importance of maximizing these collection events because these trips are super expensive. One trip to Mongolia, you know, averages about $75,000 for that month and a half, and so we try to maximize what we get out of that and to give back to the scientific community. Um, but I've had lots of graduate students work on it. I have a PhD student working on a lot of the data sequencing genomes from a lot of these different parasites. Um, my colleagues kind of contribute a lot. So, this work in Vietnam as well, um, you know, hopefully will connect some of my students to the students there, although they won't travel directly. Um, I do have colleagues coming over to visit and help with some of the collecting, and they might bring some of their students with them from the University of New Mexico. The University of New Mexico, the Museum of Southwestern Biology, is actually contributing different batnets and vials and liquid nitrogen tanks and other things because a lot of those specimens can go back to that collection to be utilized. We'll send you know ticks to the National Tick Collection here. Right. We just got an NIH grant to look at hyaloma. There's some hyaloma in Vietnam that are important for our phylogeny, so we'll get those that will contribute. And all of this, you know, work gets done by graduate students and undergraduates when they come back to the lab. So hopefully this builds other students' careers in parasitology.
SPEAKER_00And I take it that for a lot of these students, this is probably their first published paper as well, right? Oh, yeah, yeah. Great great chance for them to make a move and get established as well. So that's fantastic. So, what aspects of your current research excite you the most, and what directions are you eager to explore next?
SPEAKER_01Yeah, I mean, I think one of my biggest passions is fieldwork. I do like to get out, so Vietnam's amazing. I'm gonna go there, I'll teach a class in medical parasitology that I'm actually teaching tonight online at 2.30 in the morning. Wow. Everybody set your clocks, okay? And to kind of have a nice connection so that I teach the whole class and students get to meet me instead of having somebody else teach those first two classes. I'll teach, you know, 1.30 p.m. in Vietnam time is you know 2.30 in the morning here. It's an 11-hour time difference. So I get to jump on. Hopefully, I'll have some sleep before then. Yeah. After this, but um, yeah, so just being able to do field work and do biodiversity discovery and identify new parasite species is probably one of my biggest passions when it comes to my research. But looking forward, there's so many new technologies now that come around and new things develop. And so we're also trying to push into the genomic era of parasitology as well. And by doing that, when we sequence whole genomes of the parasites, you can actually get their symbionts as well. So you get these kind of metagenomic samples from a single species, and you get to see all the other species that are associated with it. So let's say we have one tapeworm, it could have a lot of bacteria that are on its tegument or its skin, or within it that could also be transmitted to the host, or it could tell you something about the host's health as well. Uh, and so being able to do more genomic sequencing, I think, is kind of the direction that most research is going into.
SPEAKER_00So, just so our listeners have some some sense of how complicated that is, how long does it take to sequence a genome for a parasite like this?
SPEAKER_01Yeah, I mean the nice thing is technology's advanced so rapidly that things have gotten cheaper and cheaper and cheaper. You know, when I was a graduate student, you had to do shotgun sequencing and cloning and put everything to bacteria, and it could take years to get a genome. Now we extract DNA in the lab, we get a little tube with a little bit of liquid in it, ship it off to a company, NovaGene, or a bunch of others, uh, and then they'll sequence it on different machines. So they'll do the library prep where they add in kind of primers and barcodes so you know what samples what. And they can sequence it within a couple of weeks, send you, you know, terabytes of data back. So you get hundreds of millions of sequence reads that are short or long, depending on the sequencing platform you use. Uh, but then the kind of the harder work comes in. So the sequencing is pretty easy. The assembling, the annotating, identifying what genes are what, um, and uh putting the whole genome together from 150 base pair fragments is really tough and computationally intensive, and that can take you know months to years to really finalize and get a really strong product back.
SPEAKER_00This is where you're touching on high performance computing, sifting through that terabytes of data.
SPEAKER_01Yeah, you can't do it. AI is definitely making it much easier. You can ask it, oh, what's the best technique? But it requires the infrastructure to be able to do it, and that requires those supercomputers to actually run it because it requires lots and lots of processing power. Because you're a single sample, let's say one tapeworm, the genome's quite small. Um, but you get like, you know, probably on average per sample is about 300 gigabytes of data per sample. And so having that run through a machine and match up those base pairs ends up being really, really computationally high.
SPEAKER_00I'm gonna date myself here by simply saying that I can remember when I was in grad school, those floppy disks that we had, it was like one megabyte on each. That would be a lot of floppy disks to go through all that stuff.
SPEAKER_01I'm glad we have the grad student, I had to use zip drives. Yes, I remember a little bit better than floppy disks. Yeah, exactly. They broke all the time.
SPEAKER_00Yeah, that's right. That's right. Incredible. All right, well, listen, as we wrap up today, tell us one thing about you that someone would not know about you just by reading your research.
SPEAKER_01Yeah, that's a tough one. Uh I mean, personally, I have two kids. I don't think anybody would know that I have two children from reading my research. So, you know, they're really excited as well. They get to come to Vietnam as well as my wife. Um, and so hopefully the experience for them is as exciting as it will be for me. And they're really young, so they're only five. And well, she'll actually turn six in Vietnam next month, so that's exciting. Yeah, she's sad that she's gonna miss Halloween, but that's her favorite holiday. Uh but hopefully there'll be some Halloween-esque kind of thing happening in Vietnam. And then my son is only three, so we'll see if he remembers anything. But that's kind of a big area now, is once you have kids, they kind of take up a lot of time.
SPEAKER_00Absolutely. Absolutely. They always say that uh the days are long, but the years are fast. Oh, yeah, like crazy. Yeah, it really does. Well, Stephen, thank you so much for joining us on The Roots of Research, where Georgia Southern scholars soar beyond. Thank you all.