Carminic acid and its metal derivatives have been used widely as pigments for fabrics and art, and more recently as a colorant for food. An undergraduate teaching laboratory is described in which students are instructed to design and execute experimental studies to obtain detailed information about the electronic structure, metal complex formation, redox properties, and photochemical stability of extracted carminic acid. The lab maintains room for student innovation and is wellsuited to upper-level undergraduates in an advanced spectroscopy lab. Students are invited to apply knowledge previously gained through highly directed experiments to the analysis of an unfamiliar, complex, and relevant problem. The laboratory lends itself to flexibility in implementation but is designed to deepen students' understanding of UV−vis spectroscopy, fluorescence spectroscopy, IR spectroscopy, electrochemistry, pH and metal spectrophotometric titrations, and experimental determination of the kinetic behavior of UV-induced decomposition.

T cells play critical roles in the recognition and elimination of foreign pathogens in the host immune system. The T cell receptor (TCR) is responsible for activating T cells and discriminating between foreign antigens and inappropriate expression of endogenous proteins. Control of T cell signaling occurs through both positive and negative regulation. Two members of the suppressor of TCR signaling (Sts) family of proteins, Sts‐1 and Sts‐2, have been shown to be functionally redundant negative regulator of signaling pathways downstream of the TCR. Sts‐ 1 contains a C‐terminal histidine phosphatase (HP) catalytic domain. This domain of mouse Sts‐ 1 has been shown to have an intrinsic phosphatase activity to dephosphorylate Zap‐70, which contributes to the negative regulation of signaling pathways downstream of the TCR. Moreover, Sts‐knockout mice displayed significantly enhanced survival after infection with the fungal pathogen C. Albicans. The goal of my research is to establish human Sts‐1 as a viable drug target, and identify novel small molecule inhibitors of Sts‐1 as lead compounds for future development into adjuvant therapeutics for systemic fungal infections. To better understand the molecular determinants of function and structure of Sts‐1 in humans, the structure and steady‐state kinetics of the histidine phosphatase domains of human Sts‐1 (Sts‐ 1HP) have been characterized. We determined the X‐ray crystal structures of Sts‐1HP, unliganded and in complex with sulfate to 2.5 Å and 1.9 Å, respectively. The steady‐state kinetic analysis revealed that human and mouse Sts‐1 have similar kinetic properties. In addition, comparison of phosphatase activity of the full‐length Sts‐1 protein to that of Sts‐1HP reveals that Sts‐1HP is a functional surrogate for the native protein. Additionally, we demonstrated that human Sts‐1HP has robust phosphatase activity against Zap‐70 in a cell‐based assay. To identify and validate novel small molecule inhibitors of Sts‐1, we tested a set of known phosphatase inhibitors and identified that the SHP‐1 inhibitor, PHPS1, is a potent inhibitor of Sts‐1. We then conducted a 20,580‐compound high throughput screening using an optimized 1536‐well format phosphatase assay with human Sts‐1HP. The screen yielded 51 active compounds (IC50 < 10 μM) that were inactive in an enzyme‐minus counter‐screen. There were two main groups of compounds with similar structural scaffolds among these 51 hits. Using kinetic assays, we determined that these two classes of compounds are competitive inhibitors of Sts‐1HP. Comparison of Ki values for Sts‐1HP to canonical protein tyrosine phosphatases, including PTP1B and SHP1, indicates that these two groups of compounds can inhibit Sts‐1HP selectively. In addition, several mutations at the active site were made to explore which active site features of the enzyme contribute to inhibitor binding. These mutations decrease the inhibitory activity by 3 to 18 fold while not dramatically altering the enzyme activity. Taken together, these data suggest that the human...

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Spatial variation in cellular phenotypes underlies heterogeneity in immune recognition and response to therapy in cancer and many other diseases. Spatial transcriptomics (ST) holds the potential to quantify such variation, but existing analysis methods address only a small part of the analysis challenge, such as spot deconvolution or spatial differential expression. We present BayesTME, an end-to-end Bayesian method for analyzing spatial transcriptomics data. BayesTME unifies several previously distinct analysis goals under a single, holistic generative model. This unified approach enables BayesTME to (i) be entirely reference-free without any need for paired scRNA-seq, (ii) outperform a large suite of methods in quantitative benchmarks, and (iii) uncover a new type of ST signal: spatial differential expression within individual cell types. To achieve the latter, BayesTME models each phenotype as spatially adaptive and discovers statistically significant spatial patterns amongst coordinated subsets of genes within phenotypes, which we term spatial transcriptional programs. On human and zebrafish melanoma tissues, BayesTME identifies spatial transcriptional programs that capture fundamental biological phenomena like bilateral symmetry, differential expression between interior and surface tumor cells, and tumor-associated fibroblast and macrophage reprogramming. Our results demonstrate BayesTME's power in unlocking a new level of insight from spatial transcriptomics data and fostering a deeper understanding of the spatial architecture of the tumor microenvironment. BayesTME is open source and publicly available (https://github.com/tansey-lab/bayestme).