Plants can get rusty. No joke! There is a fungal pathogen called rust which can cover the leaves of plants. This is problematic given that leaves are the site where photosynthesis occurs, the process whereby plants use sunlight to synthesize foods from carbon dioxide and water in order to grow. While a plant may still be able to photosynthesize if the leaves contain just a little bit of rust, the more and more rust spreads across the leaves, the less and less surface area there is for photosynthesis to occur. When you get rust on a metallic item, there are several home remedies you can try to remove the rust, such as baking soda or a vinegar bath. But do plants have rust-removal options too? Possibly…and it’s what our guest this week, PhD student Maria-Jose Romero-Jimenez (or Majo), is trying to figure out.
Rusty leavesRusty leaves
Majo, who is in her second year of graduate school in the Department of Botany and Plant Pathology here at OSU, is using black cottonwood as her plant study species. Black cottonwood is a Pacific Northwest native which has many uses, including the paper industry in Oregon. Recently, the Department of Energy has also listed the black cottonwood as a plant of interest for its potential use as a biofuel. As you can imagine, with this much large-scale interest in black cottonwood, there is also huge interest in understanding how it is affected by disease and pathogens, and what can potentially be done to prevent pathogens, such as rust, from spreading.
Yeast diversity panel
Fortunately, it seems like black cottonwood has a natural ally that helps it fend off rust – yeast! Majo’s main research goal is to figure out what yeast colonies are able to prevent rust infestation of black cottonwood plants. While this task may sound relatively straightforward, it sure isn’t. Majo’s work involves both field and lab work and is started in the fall of 2020 when Majo had to isolate yeast colonies from a bunch of leaves that were collected in the PNW (primarily Washington and Oregon). This work resulted in isolating almost 400 yeast colonies, from which Majo had to select a subset to grow in the lab. Meanwhile, baby black cottonwood plants needed to be propagated, potted, and cared for to ensure that Majo would have enough grown plants for her first round of greenhouse experiments. These experiments involved a series of treatments with different combinations of yeast colonies that were applied to the black cottonwood plants before being sprayed with rust to see how plants in different yeast treatments would do.
Curious to know what the results of Majo’s first round of experiments was and what the next steps are? You can download the episode anywhere you get your podcasts! Also, check out Majo’s Instagram (@fungibrush) for some educational videos on how she conducts her research (as well as a lesson in Spanish!).
It might sound like science fiction, but you’ve probably heard the phrase ‘gut-brain axis’ used in recent years to describe this phenomenon. What we call the “gut” actually refers to the small and large intestines, where a collection of microorganisms known as the gut microbiome reside. In addition to the microbes that inhabit it, your gut contains around 500 million neurons, which connect to your brain through bidirectional nerves – the biggest of which is the vagus nerve. Bacteria might be able to interact with specialized sensory cells within the gut lining and trigger neuronal firing from the gut to the brain.
Our guest this week is Caroline Hernández, a PhD student in the Maude David Lab in the Department of Microbiology, and she is studying exactly this phenomenon. While the idea that the gut and the brain are connected is not exactly new (ever heard the phrase “a gut feeling” or felt “butterflies” in your gut when you’re nervous?), there still isn’t much known about how exactly this works on a molecular level. This is what Caroline’s work aims to untangle, using an in vitro(which means outside of a living organism – in this case, cells in a petri dish) approach: if you could grow both the sensory gut cells and neurons in the same petri dish, and then expose them to gut bacteria, what could you observe about their interactions?
Caroline Hernández in her lab at Oregon State, using a stereo microscope to identify anatomical structures in a mouse before dissecting out a nerve bundle
The answer to this question could tell us a lot about how the gut-brain axis works on a molecular level, and could help researchers understand the mechanisms by which the gut microbiome can possibly modulate behavior, mood, learning, and cognition. This could have important implications down the line for how we conceptualize and potentially treat mood and behavioral disorders. Some mouse studies have already shown that mice treated with the probiotic Lactobacillus rhamnosus display reduced anxiety-like and depressive behaviors, for example – but exactly how this works isn’t really clear.
The challenges of in vitro research
Before these mechanisms can really be untangled, there are several challenges that Caroline is working on solving. The biggest one is just getting the cells to grow at all: Caroline and her team must first carefully extract specific gut sensory tissue and a specific ganglion (which is a blob of neurons) from mice, a delicate process that requires the use of specialized tools and equipment. Once they’ve verified that they have the correct anatomy, the tissues are moved into media, a liquid that contains specialized nutrients to help provide the cells with the growth factors they need to stay alive. Because this is very cutting-edge research, Caroline’s team is among the first in the world to attempt this technique – meaning there is a lot of trial and error and not a great amount of resources out there to help. There have been a number of hurdles along the way, but Caroline is no stranger to meeting challenges head-on and overcoming them with incredible resilience.
From art interactions to microbial interactions
Her journey into science started in a somewhat unexpected way: Caroline began her undergraduate career as a studio art major in community college. Her art was focused on interactivity and she was especially interested in how the person perceiving the art could interact with and explore it. Eventually she decided that while she was quite skilled at it, art was not the career path she wanted to pursue, so she switched into science, where she began her Bachelors of Science in molecular and cellular biology at the University of Illinois in Urbana Champaign.
During her undergraduate degree, a mental health crisis prompted Caroline to file for a medical withdrawal from her program. The break was much needed and allowed her to focus on taking care of herself and her health before returning to the rigorous and intense program three years later. Caroline is now a strong supporter of mental health resource awareness – in this episode of Inspiration Dissemination she will describe some of the challenges and barriers she faced when returning to finish her degree, and some of the pushback she faced when deciding to pursue a PhD.
“Not everyone was supportive,” she says. “I didn’t receive great encouragement from some of my advisors.”
Where she did find support and community was in her undergraduate research lab. Her work in this lab on the effects of diet and the microbiome on human health gave her the confidence to pursue graduate school, demonstrating that she was more than capable of engaging in independent research. In particular Caroline recalls her mentor Leila Shinn, a PhD student at the time in that lab, who had a profound impact on her decision to apply to graduate programs.
Tune in on Feb 27th to hear the rest of Caroline’s story and what brought her to Oregon State in particular. You can listen live at 7 PM PST on 88.7 FM Corvallis, online at https://kbvrfm.orangemedianetwork.com, or you can catch the episode after the show airs wherever you get your podcasts.
If you are an undergraduate student or graduate student at Oregon State University and are experiencing mental health struggles, you’re not alone and there are resources to help. CAPS offers crisis counseling services as well as individual therapy and support and skill-building groups.
At OSU there is a building called Milam Hall. It sits across the quad from the Memorial Union and houses many departments, including the School of History, Philosophy, and Religion, where our guest this week, History and Philosophy of Science M.A. student Kathleen McHugh is housed. The building is certainly showing its age, with a perpetually leaky roof and well worn stairwells. But despite this, embedded in some of its classrooms, are hints of its former glory. It was once the location of the School of Home Economics, and was posthumously named after its longstanding dean, Ava B. Milam. While no books have been written about Milam, aside from her own autobiography, her story is one worth telling, and McHugh is doing just that with her M.A. thesis where she explores Milam’s deliberate actions to make home economics a legitimate scientific field.
Home Economics students cooking. Courtesy of Industrial-Arts Magazine.
During Milam’s tenure, home economics was a place where women could get an education and, most importantly, where they would not interfere with men’s scientific pursuits. It necessarily othered women and excluded them from science. But McHugh argues that Milam actively tried to shape home economics so that it was perceived as a legitimate science rather than a field of educational placation. And, as McHugh demonstrates through her research, in part due to Milam’s work, women are able to study science today without prejudice (well, for the most part. Obviously there is still a long way to go before there is full equality).
But exactly how Milam legitimized a field that–let’s be honest, probably immediately gives readers flashbacks of baking a cake in middle school or learning how to darn a sock –is exactly what McHugh explores in her thesis. Through meticulous archival research, and despite COVID hurdles, McHugh has created a compelling and persuasive narrative of Milam’s efforts to transform home economics into a science.
Guests waiting outside a tearoom at the 1919 San Francisco World’s Fair run by Home Economics students. Courtesy of Industrial-Arts Magazine.
Listen this week and learn how a cafe at the 1915 San Francisco World’s Fair and a house near campus that ran a nearly 50 year adoption service relate to Milam and her pioneering work. If you missed the live show, listen to this episode wherever you get your podcasts.
This week we have a PhD candidate from the materials science program, Jaskaran Saini, joining us to discuss his work on the development of novel metallic glasses. But first, what exactly is a metallic glass, you may ask? Metallic glasses are metals or alloys with an amorphous structure. They lack crystal lattices and crystal defects commonly found in standard crystalline metals. To form a metallic glass requires extremely high cooling rates. Well, how high? – a thousand to a million Kelvin per second! That high.
The idea here is that the speed of cooling impacts the atomic structure – and this idea is not new or limited to just metals! For example, the rocks granite, basalt, pumice, and obsidian all have a similar composition, but different cooling times. This even gives Obsidian an amorphous structure, which means we could probably just start referring to it as rocky glass. But the uses of metallic glass extend far beyond those of rocks.
(Left) Melting the raw materials inside the arc-melter to make the alloy. The bright light visible in the image is the plasma arc that goes up to 3500C. The ring that the arc is focusing on is the molten alloy. (Right) Metallic glass sample as it comes out of the arc-melter; the arc melter can be seen in the background.
Close-ups of metallic glass buttons.
Why should we care about metallic glass?
Metallic glasses are fundamentally cool, but in case that isn’t enough to peak your attention, they also have super powers that’d make Magneto drool. They have 2-3x the strength of steel, are incredibly elastic, have very high corrosion and wear resistance and have a mirror-like surface finish. So how can we apply these super metals to science? Well, NASA is already on it and is beginning to use metallic glasses as gear material for motors. While the Curiosity rover expends 30% of its energy and 3 hours heating and lubricating its steel gears to operate, Curiosity Jr. won’t have to worry about that with metallic glass gears. NASA isn’t the only one hopping onto the metallic glass train. Apple is trying to use these scratch proof materials in iPhones, the US Army is using high density hafnium-based metallic glasses for armor penetrating military applications, and some professional tennis and golf players have even used these materials in their rackets and golf clubs. But it took a long time to get these metallic glasses to the point where they’re now being used in rovers and tennis rackets.
Metallic glass: a history
Metallic glasses first appeared in the 1960’s when Jaskaran’s academic great grandfather (that is, his advisor’s advisor’s advisor), Pol Duwez, made them at Caltech. In order to achieve this special amorphous structure, a droplet of a gold-silicon alloy was cooled at a rate of over a million Kelvin per second with the end result being an approximately quarter sized foil of metallic glass, thinner than the thickness of a strand of hair. Fast forward to the ‘80’s, and researchers began producing larger metallic glasses. By the late ‘90’s and early 2000’s, the thickness of the biggest metallic glass produced had already exceeded 1000x the original foil thickness. However, with great size comes greater difficulty! If the metallic glass is too thick, it can’t cool fast enough to achieve an amorphous structure! Creating larger pieces of metallic glass has proven itself to be extremely challenging – and therefore is a great goal to pursue for graduate students and PI’s interested in taking on this challenge.
Currently, the largest pieces of metallic glasses are around 80 mm thick, however, they use and are based on precious metals such as palladium, silver, gold, platinum and beryllium. This makes them not very practical for multiple reasons. First, is the more obvious cost standpoint. Second, given the detrimental impact of mining rare-earth metals, efforts to minimize dependence on rare-earth metals can have a great positive impact on the environment.
World records you probably didn’t know existed until now
As part of Prof. Donghua Xu’s lab, Jaskaran is working on developing large-sized metallic glasses from cheaper metals, such as copper, nickel, aluminum, zirconium and hafnium. It’s worth noting that although Jaskaran’s metallic glasses typically consist of at least three metal elements, his research is mainly focused on producing metallic glasses that are based on copper and hafnium (these two metals are in majority). Not only has Jaskaran been wildly successful in creating glassy alloys from these elements, but he has also set TWO WORLD RECORDS. The previous world record for a copper-based metallic glass was 25 mm, which he usurped with the creation of a 28.5 mm metallic glass. As for hafnium, the previous world record was 10 mm which Jaskaran almost doubled with a casting diameter of 18 mm. And mind you, these alloys do not contain any rare-earth or precious metals so they are cost-effective, have incredible properties and are completely benign to the environment!
The biggest copper-based metallic glass ever produced (world record sample).
Excited for more metallic glass content? Us too. Be sure to listen live on Sunday February 6th at 7PM on 88.7FM, or download the podcast if you missed it. Want to stay up to date with the world of metallic glass? Follow Jaskaran on Twitter, Instagram or Google Scholar. We also learned that he produces his own music, and listened to Sephora. You can find him on SoundCloud under his artist name, JSKRN.
Jaskaran Saini: PhD candidate from the materials science program at Oregon State University.
This post was written by Bryan Lynn and edited by Adrian Gallo and Jaskaran Saini.
