This week will feature both an undergraduate presentation and one by a soon-to-be graduated M.S. student. The first, Victoria Silvis, will discuss her honors thesis research in Dr. Cooper's lab. The second student, Sarah Marshall, will present the results of her thesis work under Dr. Butcher's mentorship.
Bring your lunch to share! See you Friday!
For this week's seminar we were delighted by two presentations presented by two enthusiastic and phenomenal women I have the pleasure to call friends: Victoria Silvis and Sarah Marshall.
ReplyDeleteVictoria led first in her honors research on proteins putatively secreted by the yeast phase of T. marneffei. As a refresher, T. marneffei is a dimorphic opportunistic fungus causing the disease talaromycosis in immunosuppressed individuals. The yeast phase is infamous for its ability to live inside host macrophages and it may secrete proteinacious factors to aid its survival inside of the macrophages. Victoria's research involved designing primers with FunSecKB then using the DNA sequences acquired to run a BLAST search. The primers (3700 and 3601) were used in RTPCR at 25C and 37C and measured after multiple timepoints. Interestingly the 96 hr 37C (when the fungi had fully developed into yeast cells) resulted in bright banding and was used to run qRTPCR which found extremely high levels of 3700 (multi-copper oxidase) and 3601 (catalase). Both of these function as virulence factors in other pathogenic fungi which suggests T. marneffei uses these as virulence factors as well, being only expressed in the yeast phase. Question: What would be the next steps now that this possible virulence factor has been found?
Sarah took the plate next in her bubbly talk about the fascinating group of animals known as Xenarthra, which include sloths, anteaters, and armadillos. Her research involved taking hindlimb bone measurements of these varying species since most research focuses on forelimb morphology. She wanted to see whether the morphology in hindlimbs can also predict the distinct lifestyles of these animals. To do so she took length, width, and depth measurements of multiple hindlimb bones and used them to calculate 27 functional indices. And this is where I get a little lost in the complex statistical analyses so please correct me if I get anything wrong Sarah. She used two different analyses: PCA and DFA and here are the major discoveries. Armadillos exhibited bone robustness with larger condyles and protuberances which provide more joint stability and mechanical advantage in order to scratch dig. Anteaters had intermediate features indicative of their mixed arborial and terrestrial habits. Sloths exhibited bone gracility with smaller condyles and protuberances which provide more joint rotations and limb mobility in order to climb and hang. Question: How does having such a low metabolism benefit the Xenarthrans when they have very distinct lifestyles from one another? In other words, why has the low metabolism been selected for in their distinct environments?
Excellent summary, Kayla! The presentations this week were fantastic! Victoria and Sarah both did an awesome job explaining their research to us.
ReplyDeleteTo answer the question about Victoria’s research, I think now that the virulence factors have been found it would be interested to try and knock out the genes and see how that alters growth. I’m not quite sure how that would work since the gene is more strongly expressed in different stages of growth, but I think it might be an avenue worth exploring.
As for Sarah’s presentation, Xenarthrans are, again, not my strong point, but I’ll give Kayla’s question a shot. With sloths it’s a little easier to understand why having a low metabolism is ideal for them. Since they are slow moving and receive little nutrition from their food source (I’m assuming) it makes sense that they would have a lower metabolic rate to conserve energy. Armadillos and anteaters on the other hand don’t share the same lifestyles as sloths. Their muscle use and structure probably lend itself to metabolic rates. I was also reading an article (can’t seem to find it again) that was discussing their low metabolism to be for various reasons such as low predation and competition, specifically in the armadillo since it is considered an armored animal. I’m interested to see what Kyle and Marissa add to this discussion as I’m sure they’re much more knowledgeable on the topic.
I feel like I start my seminar posts the same way each week by saying that the presenters did an excellent job, but this was again the case this past week which underscores the quality of research, students, and faculty that we have in our department at YSU. Regarding Kayla’s question on Victoria’s talk, I agree with Jamielynn that it would be interesting to see how a knock-out strain would affect the growth of this organism. Furthermore, it was brought up in questioning why there was a higher peak in the qRT-PCR data at a shorter time then there was in the time of growth before and after. Although I can’t recall the times of growth when the analyses were conducted, Dr. Cooper suggested that a morphological change may have been occurring that caused the heightened expression level, so it would be interesting to specify exactly what was causing that spike. As far as the question regarding Sarah’s work, I think that maybe a low metabolism was evolutionarily selected for possibly because of the efficiency of the organisms. I know very little about Xenarthrans other than what I have heard from Dr. Butcher’s students this term, so the only assumption that I would make is that the less they need to acquire, the more beneficial regarding behavior and environment, thus the evolutionary selection.
ReplyDeleteYet again another set of great presentations. Way to go! Commenting on Jamielynn's suggestion of a more in depth look at knocking out the gene, what would this tell us about the growth? If the gene is expressed in different stages of growth, would this tell us about growth patterns if it was altered? I agree everything I know about Xenarthrans has come from this semester listening to Dr. Butcher's students. It seems a low metabolism has given them the benefits of living a certain lifestyle. Little energy in, little energy out. Really enjoyed these two presentations!
ReplyDeleteI apologize to Victoria and Sarah for missing seminar last week. I was out of town for a conference. However, I have no doubt that these two gave awesome presentations!
ReplyDeleteFor the question regarding Victoria’s work, I am in no way specialized in this area of biology. I agree with Jamielynn and John though, that the next steps would be to see how a knock-out strain would influence the growth of the organism.
In terms of the question on Sarah’s work, I can’t speak too much about armadillos and anteaters, I just know the basics about them since my work is specifically focused on sloths. The three different animals have low metabolisms though because they have very low nutritional diets, especially the sloths. The warm climates that they live in are also advantageous for their low metabolisms. For example, three-toed sloths will undergo behavioral thermoregulation by climbing to the top of the canopies and warming themselves in the sun then they recess into the shades of the canopies when the sun becomes too warm. Further, armadillos will burrow for shelter and warmth. So, although they have low metabolisms, they are found only in warm climates to counterbalance their low body temperatures that are a result of their low metabolisms. It’s all about saving energy. Remember sloths aren’t lazy, they’re just in energy-savings mode!
You could have fooled me by saying that Victoria is graduate student. She did a fine job presenting, and congratulations on her acceptance to Penn State (if I remember correctly). I think that the T. marneffei project requires a little more fundamental research before handing it over to applied scientist. It seems the general consensus on the blog board is that the next logical step is to knockout the putative genes that ensure survival of T. marneffei while engulfed in alveolar macrophages. If gene knockout successfully reduces the risk of infection, then the next step would be to figure out the best way administer gene vectors to the fungi. Dr. Jake Socha of Virginia Tech is trying to understand how mosquitos pump blood. Once the mechanism is better understood it could be applied to directly targeting certain regions and administer drugs or vectors to specific sites. In the case of T. marneffei the targeted site would be deep lung regions of infected people. Maybe this is the future of medicine!
ReplyDeleteWith respect to metabolism, low and slow is the way to go. Xenarthrans are ancient and in many ways share characteristics of proto-mammals. I doubt that low metabolic rate is a derived feature and likely arose in the common ancestor. So why retain this feature? Because the slower the metabolism, the better the energy economy. Xenarthrans may not have had to evolve higher metabolic rates because selection pressures did not demand it. I wonder if this is because sloths, anteaters, and armadillos solved the evolutionary arms race in other ways. Armadillos have armor, and sloths ascended to the tree canopy and move slowly to avoid detection. Some anteaters ascended to the canopy, and they move slowly albeit not as slow as sloths. Perhaps this is why low metabolism is retained in the basal mammalian clade. I feel like I’m going out on a limb here (pun fully intended), but that’s my two cents. Cheers!
Both presenters did awesome job. To respond to Kayla’s question on Victoria’s project, I would absolutely implement Jamielynn’s idea of knocking out one or both genes to alter the dimorphic nature which may probably lower the virulence in T. Marneffei. Regarding Low metabolism on Xenathrans, I am not much familiar with this family, but I know habitation and adaptation play key role in ecosystem. I think, since the food intake capacity is low of which they struggle to get, the body mechanism is evolutionary adapted to conserve and reduce the energy lost by lowering the metabolic rate.
ReplyDeleteBoth presenters did awesome job. To respond to Kayla’s question on Victoria’s project, I would absolutely implement Jamielynn’s idea of knocking out one or both genes to alter the dimorphic nature which may probably lower the virulence in T. Marneffei. Regarding Low metabolism on Xenathrans, I am not much familiar with this family, but I know habitation and adaptation play key role in ecosystem. I think, since the food intake capacity is low of which they struggle to get, the body mechanism is evolutionary adapted to conserve and reduce the energy lost by lowering the metabolic rate.
ReplyDeleteKnocking out the gene was the first thing that came to mind for me, but everyone already mentioned that. Would it be possible to isolate the proteins, pan them against a phage library, produce produce the expressed phage peptide, and basically drown the culture in it such that it inhibited protein function? Clearly that introduces a lot of unknown factors and obstacles but at least it would be fun! I am guessing that Xenarthrans evolutionarily developed as in a niche environment in which their food source, lifestyle, and predators made it easy to have a low basal metabolic rate, then these three organisms diverged but continued to reap the benefits of a low BMR. I'm not sure. Good job to both Victoria and Sarah, it was fun to listen to you both!
ReplyDeleteVictoria and Sarah’s talks were delightful! I would agree that knocking out the genes might the shortest path to an application for these findings, but I would prefer to look down the road at the possibly more efficient target: identifying the proteins responsible for regulating these genes. It’s possibly that some transcription factor could be activating groups of these genes that only get expressed in the yeast form. It might be possibly to knock out a gene that activates all of the virulence factors of T. marneffei! Again, this is the long term possibility, because much more primary research would be required to elucidate these regulatory proteins and pathways.
ReplyDeleteAs for the Xenarthrans, I do believe that they represent some of the basal clade of mammals, and advanced thermoregulation had not yet been required as a trait when these guys had their time. I would say the greatest benefit of a higher BMR would be highly energetic motions, such as those required to chase prey or escape predators. In the absence of such pressures, the Xenarthrans likely had no need for these higher metabolic rates, and were quite content. I believe that they all share this low BMR despite their different lifestyles and environments simply because they all inherited this trait from a common ancestor, and like this ancestor, never needed more energetic movements in order to survive and reproduce.
Sarah and Victoria both did an excellent job. To answer Kayla's question posed for Victoria's research, I found other organisms like candida albicans and S.cerevisiae also express a form of copper metalloxide, it is possible to see what factors inhibit CMO in these organisms, those same factors can also inhibit CMO in T.marfaneii.
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