Tag Archives: fungi

Infection Interruption: Identifying Compounds that Disrupt HIV

Know the enemy

Comparing microbial extracts with Dr. Sandra Loesgen.

The Human Immunodeficiency Virus, or HIV, is the virus that leads to Acquired Immunodeficiency Syndrome (AIDS). Most of our listeners have likely heard about HIV/AIDS because it has been reported in the news since the 1980s, but our listeners might not be familiar with the virus’s biology and treatments that target the virus.

  • HIV follows an infection cycle with these main stages:
    • Attachment – the virus binds to a host cell
    • Fusion – the viral wall fuses with the membrane of the host cell and genetic material from the virus enters the host cell
    • Reverse transcription – RNA from the virus is converted into DNA via viral enzymes
    • Integration – viral DNA joins the genome of the host cell
    • Reproduction – the viral DNA hijacks the host cell activity to produce more viruses and the cycle continues
  • Drug treatments target different stages in the HIV infection cycle to slow down infection
  • However, HIV has adapted to allow mistakes to occur during the reverse transcription stage such that spontaneous mutations change the virus within the host individual, and the virus becomes tolerant to drug treatments over time.

Faulty Machinery

Due to the highly mutable nature of HIV, a constant supply of new drug treatments are necessary to fend off resistance and treat infection. Our guest this week on Inspiration Dissemination, Ross Overacker a PhD candidate in Organic Chemistry, is screening a library of natural and synthetic compounds for their antiviral activity and effectiveness at disrupting HIV. Ross works in a Natural Products Lab under the direction of Dr. Sandra Loesgen. There, Ross and his lab mates (some of whom were on the show recently [1] [2]) test libraries of compounds they have extracted from fungi and bacteria for a range of therapeutic applications. Ross is currently completing his analysis of a synthetic compound that shows promise for interrupting the HIV infection cycle.

“Uncle Ross” giving a tour of the lab stopping to show off the liquid nitrogen.

Working in Lab with liquid nitrogen.

 

 

 

 

 

 

 

Havin’ a blast

Chemistry Club at Washington State University (WSU) initially turned Ross onto chemistry. The club participated in education outreach by presenting chemistry demonstrations at local high schools and club events. Ross and other students would demonstrate exciting chemistry demos such as filling hydrogen balloons with salt compounds resulting in colorful explosions piquing the interest of students and community members alike. Ross originally made a name in

Collecting Winter Chanterelles in the Pacific Northwest.

WSU’s chemistry club, eventually becoming the president, by showing off a “flaming snowball” and tossing it from hand to hand—don’t worry he will explain this on air. For Ross, chemistry is a complicated puzzle that once you work out, all of the pieces fall into place. After a few undergraduate research projects, Ross decided that he wanted to continue research by pursing a PhD in Organic Chemistry at Oregon State University.

 

 

Tune in this Sunday October 7th at 7 PM to hear from Ross about his research and path to graduate school. Not a local listener? Stream the show live or catch this episode on our podcast.

Unearthing the Unseen: Identifying drivers of fungal diversity in Panamanian rainforests

When our roommates or family members get sick, we try to keep our distance and avoid catching their illness. Plants get ‘sick’ too, and in the natural world, this may actually explain the coexistence and diversity of plant species that we see.

Coexistence

Species coexistence relies on competition between individuals of the same species being larger than competition between individuals of different species. Competition between individuals of the same species must be large enough to keep any species from taking over and outcompeting all other species in the community. However, more recent work has highlighted the role of natural pathogens. Stable coexistence of many species may be favored if individuals of one species cannot live in close proximity to each other due to disease.

Plant Pathogens and Biodiversity

View looking south from the canopy tower at the Gamboa Rainforest Resort over the confluence of the Panama Canal and the Chagres River near Gamboa, Panama.

For example, picture a crowded forest with many adult trees of the same species releasing wind-dispersed seeds (like the helicoptering seeds of a maple). Very few, if any, of the seeds that fall near to the adult trees will germinate and reach maturity. As you walk away from the clump of adult trees, you will begin to find more germinated seeds that reach maturity (Augspurger 1983). These seeds are farther from tough competitors of the same species (adult trees) and are away from the plant pathogens that may be living in the adult root system. In our hypothetical forest, the plant pathogens that feed on young maples are keeping maple from dominating the forest, allowing other species that aren’t affected by the pathogen to thrive; in this way, plant pathogens play a role in the maintenance of biodiversity.

Drivers of Biodiversity

Our guest this week, Tyler Schappe, studies interactions among plants and fungi in the Neotropical forests of Panama. Tyler is broadly interested in what drives the maintenance and diversity of fungal communities, and how this, in turn, can affect tree communities. Tyler spent the summer of 2015 collecting 75 soil cores from three forest plots in Panama. Using DNA sequencing with universal genetic markers, he was then able to identify the fungi within the soil cores to species and functional group (decomposers, pathogens, plant mutualists, etc.). So far, Tyler has found that tree communities and soil nutrients affect the composition and diversity of fungal guilds differently. As expected, guilds that form mutualistic relationships with trees are more strongly correlated with plant communities. Interestingly, soil properties influence the species composition of all fungal guilds, including plant pathogens, pointing to the mediating role of soils as an abiotic filter. Overall, Tyler’s results, along with other research, show that soil fungal communities are an integral component of the plant-soil relationship since they are driven by, and can affect, both. Together, plants, soil, and fungi form a tightly connected three-way relationship, and wanting to understand one of them means having to study all three together.

Tyler’s work with fungal communities in Panama sheds light on belowground interactions and their implications for plant ecology. His research is one piece of evidence that may help us to understand why there are so many plant species, how they coexist, and why some species are common and some are rare. Are plant pathogens significant contributors to species richness and biodiversity? If so, what modulates plant pathogens, and how can that indirectly affect tree communities? To find out more about Tyler’s work check out these two sources from the Journal of Ecology and Science.

Spend sugar to make sugar

Stand of bur oak trees in a remnant oak savanna at Pheasant Branch Conservancy near Middleton, WI in early winter.

At a young age, Tyler began to realize how connected the world was and how plants and animals function in an ecosystem. The functioning of organisms and of ecosystems came into focus for him while in college at University of Wisconsin-Madison. He took a course in plant ecology from Dr. Tom Givnish who described plants in terms of economic trade-offs. For example, energy invested by plants in vertical growth cannot be invested in defense or reproduction; different allocations of resources can be more or less advantageous in different environments. Tyler decided to pursue graduate school at Oregon State while completing a fellowship with the Smithsonian Tropical Research Institute in Panama, where he met his current advisor, Andy Jones.

Tyler is defending his Master’s thesis August, 29 2017!  We are glad he can make time to talk with us on Inspiration Dissemination this Sunday August, 13 at 7 pm. Not a local listener? Stream the show live!