Biological Sciences

Ronan Fast, ronan_fast1@baylor.edu
Baylor University, with Dr. James Fulton

Pigment-Related Cryptobiosis in Temperate Lichens and their Applications to Exobiology
Lichens are optimized for survival. Despite a deceptively simple appearance, lichens are succession pioneers that develop from a complex mutualism between fungi and phototrophic microbes. Lichens produce secondary metabolites that respond to a myriad of stressors. These products include numerous pigment compounds, which are considered potential biosignatures due to their ubiquity in the biosphere and their functionals roles in light exposure. In this study, we analyze and compare pigments that are produced in lichen cortices, namely the anthraquinone parietin, the depsidone atranorin, and scytonemin - each of which exhibit UV-screening behavior. We hypothesize that exposure to long wavelength UVA "black light" stress stimulates production of these photoprotective UV-screening pigments. These pigments also have antioxidant properties, and we hypothesize exposure to salt stress also stimulates production. Our lichen samples include foliose grey-blue species of the genus Physcia and orange Xanthoria, which often cohabitate in temperate conditions alongside dark patches, of non-lichenized cyanobacteria. We aim to induce pigment production by incubating samples of lichenized bark under black light and increased salinity, with the goal of evaluating the importance of these protective compounds in lichen environmental resistance. The pigments are extracted thrice over a one month period via acetone wash, then characterized through HPLC/LC-MS with comparison to chemical standards. Our checkpoints for extraction include TO, our control, T2, the midpoint, and TF, the concluding extraction. We will contrast pigment levels in each of four experimental conditions to determine lichen response to-altered stress environments, with potential application to detection by remote sensing.
 

Noah Mejia, neatterrorbusiness@gmail.com
Azusa Pacific University, with Dr. Sandor Volkan-Kacso

The Modeling of Fl-ATP Synthase With the Langevin Equation and its Applications 
Adenosine Triphosphate (ATP) is the source of all energy for cellular functions and is primarily produced inside of the mitochondria with the aid of Fl-ATP synthase. Fl-ATP Synthase itself is a complex nanoscopic motor which utilizes proton translocation to power its rotary motion so that ATP may be synthesized. As such, it is difficult to understand this system or computationally represent it in a meaningful manner.

When observed via a bead-probe attached to the gamma shaft of Fl-ATP synthase, it can be found that the turbine has periods of long catalytic dwells with brief transitionary jumps to new angular positions dependent upon the previous angle. In this, there is a long period of fluctuating parabolic potential centered around a specific dwell angle, and then a sudden jump to a new dwell angle.

In this presentation the Langevin equation and its application to the F1-ATP Synthase system will be explored and its effectiveness demonstrated as a model for computationally comprehending the Fl-ATP synthase system. Moreover, applications to machine learning via Langevin-generated trajectories will be discussed in tandem with how it may be utilized to couple with previously published models. Alongside this, it will be discussed as to whether there is a kinetic intermediate in the motion of the turbine based upon simulated data, and potentially demonstrate the previously published notion that ATP release is faster when ADP binds to a different site in the Fl domain.

Jenna Schroeder, jns5327@mavs.uta.edu
The University of Texas at Arlington, with Dr. Joseph Buonomo

Glycomic Labeling of Pathogenic Bacteria Using Fluorescent Probes
No staining method exists to enable simultaneous, high-resolution labeling of the gram-negative and gram-positive cell envelope. This project proposes the development of a cellular staining protocol, intended to visualize a "Tricolor" model in pathogenic bacterial species, selected for their relevance in infection and laboratory utility. The "Tricolor" concept has not been realized in gram-negative bacteria and few examples have been engineered in gram-positive models. The development of a comprehensive staining protocol will prove beneficial to cell biology research, offering precision labeling and visualization. A novel benzoboroxole-based dye, OM-488, was engineered for high-affinity complexation with carbohydrate-rich components of the outer membrane and cell wall. OM-488 was applied as a staining reagent to non-capsular species: E. coli, P aeruginosa, Methicillin-resistant S. aureus (MRSA), and Methicillin-susceptible S. aureus (MSSA). Parameters of the staining protocol were refined. Serial dilution and colony counting were used to investigate OM-488 toxicity. Samples were imaged with fluorescent microscopy. Results between control and variable plates in serial dilutions revealed no significant differences in cell viability when treated with OM-488, indicating non-toxicity.

Fluorescent probes exhibited optimal glycan targeting when prepared under neutral (7.4 pH) conditions and exact treatment durations. Subsequent imaging depicted precise selection and labeling of the outer membrane and cell wall. Future steps will incorporate HADA, a fluorescent D-amino acid, for peptidoglycan staining in addition to OM-488 to produce a dual color model. Continued trials will aim to prove the selective binding to cellular targets and eliminate spectra overlap and bleed-through (crosstalk) between tluorophores of HADA and OM-488.