Abstract: The living cell is an intricate and synchronized organization with compartmentalization across diverse length scales. While intracellular compartments such as the lysosome and mitochondria are bound by membranes, cells also contain organelles, not confined by membranes, known as “biomolecular condensates”. Recent studies showed that many biomolecular condensates are viscoelastic materials formed from the phase separation of proteins and nucleic acids. The abrupt changes in composition and material properties of these condensates impair their biological function and are often associated with cancer, ribosomopathies, and aging disorders. Therefore, synthetic systems are required to create model biomolecular condensates in living systems. These systems aim to elucidate the biophysical principles of intracellular organization and diseases. In the first part of my talk, I will discuss our work on using protein oligomerization and sequence interactions in vivo to create multiphasic biomolecular condensates that mimic native condensate assemblies. We show that specific molecular and nanoscopic design principles can be exploited to design optogenetic fusion proteins that exhibit targeted condensation with high spatiotemporal resolution. Later in this talk, I will describe our work on synthetic polymers to form condensates that mimic the function of underwater adhesive proteins secreted by marine organisms such as mussels and sandcastle worms. In summary, the bioinspired design of macromolecules that form model biomolecular condensates represents new frontiers to ask fundamental questions on the behavior of mesoscopic biological assemblies in living cells and to inspire the design of novel functional materials.

Event Info: We will discuss what our program structure, what we do, and how the state program compliments and supports federal CERCLA mandates. We intend on highlighting examples of current site-work and how chemistry is integral to the field of environmental protection, as well as playing a part in protective and sustainable community redevelopment.

Bio: Sheri is a Registered Professional Geologist with over 24 years of experience in the environmental field, specifically in contaminated site characterization & remediation, regulation development, and beneficial reuse. After a brief stint performing geotechnical work in private consulting Sheri started with KDEP in 2000 as a Geologist with the tanks program, becoming a supervisor in the Superfund Branch in 2007.  Between 2007 and 2012, Sheri supervised the State Superfund Section, then the Federal Superfund Section before accepting the branch Environmental Scientist Consultant position.  As an E.S. Consultant, she focuses on scientific research, and regulation & policy development for Kentucky’s Superfund, Brownfields, and other programs.  In addition, Sheri serves as the technical lead for Kentucky's high priority clean-up sites. Outside of her career with the commonwealth of Kentucky, Sheri is on the Board of Advisors to the Kentucky Geological Survey and a long-time active member of the Association of State and Territorial Solid Waste Management Officials. In her free time, she enjoys traveling, hiking, cycling, reading, fiber arts, and creating stained glass. 

ABSTRACT

Ambient ionization mass spectrometry (AIMS) is an evolving soft ionization technique that directly snapshots biomolecular profiles, spatial distributions, and chemical changes from biological tissue or fluids with minimal pretreatment. I will first introduce the methodology development of two representative AIMS techniques, namely air-flow-assisted desorption electrospray ionization mass spectrometry imaging (AFADESI-MSI) and conductive polymer spray ionization (CPSI), along with their applications in preclinical anti-tumor drug research and clinical cancer diagnosis. The topic will be then shifted to using AIMS to create water microdroplets, which exhibit ultrafast kinetic and favorable thermodynamic microenvironment differing from equal volume of bulk solution phase. I will introduce my research on AIMS-based microdroplet chemistry for both bioanalysis and synthesis of basic building blocks of life materials.

Adoption of the correct three dimensional structures by biomolecular complexes in solution is essential for their performance in cells, and the formation of individual non-covalent interactions can be critical to their stability and functions. There is thus much interest in developing solution-state methods of detection to determine the arrangement of atoms at particular locations in these complexes, and that are sensitive to the stabilities of the local structural motifs they form. The Stelling group develops the vibrational states of nucleic acids and an essential substrate for a broad range of enzymatic reactions, s-adenosyl-l-methionine (AdoMet), as solution state sensors of local structure and energetics when they are contained within the large number of complexes that bind them in cells. Over the short term, the dimensions of specific vibrational states of the nucleic acids and AdoMet will be determined via rigorous isotope labeling and computational studies. Over the long term, these submolecular-scale sensors will be deployed to examine local structure and dynamics in the active sites of the vast number of enzymes that use AdoMet as a substrate, and to probe nucelobase structure and stability in DNA and RNA containing nuceloprotein complexes.

Abstract: The vast majority of chemistry and biology occurs in solution, and new label-free analytical techniques that can help resolve solution-phase complexity at the single-molecule level can provide new microscopic perspectives of unprecedented detail. Here, we use the increased light-molecule interactions in high-finesse fiber Fabry-Pérot microcavities to detect individual biomolecules as small as 1.2 kDa (10 amino acids) with signal-to-noise ratios >100, even as the molecules are freely diffusing in solution.  Our method delivers 2D intensity and temporal profiles, enabling the distinction of sub-populations in mixed samples. Strikingly, we observe a linear relationship between passage time and molecular radius, unlocking the potential to gather crucial information about diffusion and solution-phase conformation. Furthermore, mixtures of biomolecule isomers of the same molecular weight can also be resolved. Detection is based on a novel molecular velocity filtering and dynamic thermal priming mechanism leveraging both photo-thermal bistability and Pound-Drever-Hall cavity locking. This technology holds broad potential for applications in life and chemical sciences and represents a major advancement in label-free in vitro single-molecule techniques.

Methanogens are a diverse group of archaea with ancient evolutionary origins. They are found in a wide range of anoxic environments where they carry out a form of anaerobic respiration known as methanogenesis. This process reduces simple oxidized carbon compounds to generate methane as an end product. Another group of archaea related to methanogens carry out the anaerobic oxidation of methane (AOM) and are known as anaerobic methanotrophs (ANME).  Methanogens and ANME are both key components in the global carbon cycle and play a central role in controlling atmospheric methane concentrations. Consistent with their anaerobic lifestyles and ancient evolutionary origins, methanogens and ANME contain an abundance of Fe-S cluster proteins. Radical S-adenosylmethionine (SAM) enzymes are [4Fe-4S]-cluster containing enzymes that catalyze a wide variety of difficult biochemical reactions through the generation of a highly reactive 5’-deoxyadenosyl radical. Here, we discuss our recent progress towards uncovering the functions of novel radical SAM enzymes in methanogens and ANME. We identified the missing glutamate 2,3-aminomutase important for salt tolerance in marine organisms as well as characterized the first archaeal methylthiotransferase involved in tRNA modification. 

The structure of plant cell wall carbohydrates creates the strength and flexibility of the plant cell wall, which shapes plants’ overall agronomic fitness in the field. Differences in cell wall carbohydrates and associated compounds are also influential post-harvest, since carbohydrate structural characteristics can influence a material’s food processing characteristics, feed value for livestock, and biofuel production potential.

The core areas of Dr. Schendel’s research program at the University of Kentucky are plant cell wall characterization (especially detailed structural analysis of cell wall carbohydrates) and analysis and application of phenolics and other secondary plant metabolites. Strategic collaborations have allowed us to explore applied questions such as ruminant microbe fermentation of cell wall carbohydrates. This seminar will share results from several projects, including our in-depth characterizations of the cell walls of cool-season forages and hempseeds and exploration of their seasonal and species/cultivar variation.