Academic Appointments

  • Basic Life Research Scientist, Bioengineering

All Publications

  • Previously uncharacterized rectangular bacterial structures in the dolphin mouth. Nature communications Dudek, N. K., Galaz-Montoya, J. G., Shi, H., Mayer, M., Danita, C., Celis, A. I., Viehboeck, T., Wu, G., Behr, B., Bulgheresi, S., Huang, K. C., Chiu, W., Relman, D. A. 2023; 14 (1): 2098


    Much remains to be explored regarding the diversity of uncultured, host-associated microbes. Here, we describe rectangular bacterial structures (RBSs) in the mouths of bottlenose dolphins. DNA staining revealed multiple paired bands within RBSs, suggesting the presence of cells dividing along the longitudinal axis. Cryogenic transmission electron microscopy and tomography showed parallel membrane-bound segments that are likely cells, encapsulated by an S-layer-like periodic surface covering. RBSs displayed unusual pilus-like appendages with bundles of threads splayed at the tips. We present multiple lines of evidence, including genomic DNA sequencing of micromanipulated RBSs, 16S rRNA gene sequencing, and fluorescence in situ hybridization, suggesting that RBSs are bacterial and distinct from the genera Simonsiella and Conchiformibius (family Neisseriaceae), with which they share similar morphology and division patterning. Our findings highlight the diversity of novel microbial forms and lifestyles that await characterization using tools complementary to genomics such as microscopy.

    View details for DOI 10.1038/s41467-023-37638-y

    View details for PubMedID 37055390

  • CryoET reveals organelle phenotypes in huntington disease patient iPSC-derived and mouse primary neurons. Nature communications Wu, G. H., Smith-Geater, C., Galaz-Montoya, J. G., Gu, Y., Gupte, S. R., Aviner, R., Mitchell, P. G., Hsu, J., Miramontes, R., Wang, K. Q., Geller, N. R., Hou, C., Danita, C., Joubert, L. M., Schmid, M. F., Yeung, S., Frydman, J., Mobley, W., Wu, C., Thompson, L. M., Chiu, W. 2023; 14 (1): 692


    Huntington's disease (HD) is caused by an expanded CAG repeat in the huntingtin gene, yielding a Huntingtin protein with an expanded polyglutamine tract. While experiments with patient-derived induced pluripotent stem cells (iPSCs) can help understand disease, defining pathological biomarkers remains challenging. Here, we used cryogenic electron tomography to visualize neurites in HD patient iPSC-derived neurons with varying CAG repeats, and primary cortical neurons from BACHD, deltaN17-BACHD, and wild-type mice. In HD models, we discovered sheet aggregates in double membrane-bound organelles, and mitochondria with distorted cristae and enlarged granules, likely mitochondrial RNA granules. We used artificial intelligence to quantify mitochondrial granules, and proteomics experiments reveal differential protein content in isolated HD mitochondria. Knockdown of Protein Inhibitor of Activated STAT1 ameliorated aberrant phenotypes in iPSC- and BACHD neurons. We show that integrated ultrastructural and proteomic approaches may uncover early HD phenotypes to accelerate diagnostics and the development of targeted therapeutics for HD.

    View details for DOI 10.1038/s41467-023-36096-w

    View details for PubMedID 36754966

  • Multi-scale 3D Cryo-Correlative Microscopy for Vitrified Cells. Structure (London, England : 1993) Wu, G. H., Mitchell, P. G., Galaz-Montoya, J. G., Hecksel, C. W., Sontag, E. M., Gangadharan, V. n., Marshman, J. n., Mankus, D. n., Bisher, M. E., Lytton-Jean, A. K., Frydman, J. n., Czymmek, K. n., Chiu, W. n. 2020


    Three-dimensional (3D) visualization of vitrified cells can uncover structures of subcellular complexes without chemical fixation or staining. Here, we present a pipeline integrating three imaging modalities to visualize the same specimen at cryogenic temperature at different scales: cryo-fluorescence confocal microscopy, volume cryo-focused ion beam scanning electron microscopy, and transmission cryo-electron tomography. Our proof-of-concept benchmark revealed the 3D distribution of organelles and subcellular structures in whole heat-shocked yeast cells, including the ultrastructure of protein inclusions that recruit fluorescently-labeled chaperone Hsp104. Since our workflow efficiently integrates imaging at three different scales and can be applied to other types of cells, it could be used for large-scale phenotypic studies of frozen-hydrated specimens in a variety of healthy and diseased conditions with and without treatments.

    View details for DOI 10.1016/j.str.2020.07.017

    View details for PubMedID 32814034

  • Unravelling Degradation Mechanisms and Atomic Structure of Organic-Inorganic Halide Perovskites by Cryo-EM JOULE Li, Y., Zhou, W., Li, Y., Huang, W., Zhang, Z., Chen, G., Wang, H., Wu, G., Rolston, N., Vila, R., Chiu, W., Cui, Y. 2019; 3 (11): 2854–66
  • Cryo-EM Structures of Atomic Surfaces and Host-Guest Chemistry in Metal-Organic Frameworks MATTER Li, Y., Wang, K., Zhou, W., Li, Y., Vila, R., Huang, W., Wang, H., Chen, G., Wu, G., Tsao, Y., Wang, H., Sinclair, R., Chiu, W., Cui, Y. 2019; 1 (2): 428–38
  • Cryo-EM structures of atomic surfaces and host-guest chemistry in metal-organic frameworks. Matter Li, Y., Wang, K., Zhou, W., Li, Y., Vila, R., Huang, W., Wang, H., Chen, G., Wu, G. H., Tsao, Y., Wang, H., Sinclair, R., Chiu, W., Cui, Y. 2019; 1 (2): 428-438


    Host-guest interactions govern the chemistry of a broad range of functional materials, but direct imaging using conventional transmission electron microscopy (TEM) has not been possible. This problem is exacerbated in metal-organic framework (MOF) materials, which are easily damaged by the electron beam. Here, we use cryogenic-electron microscopy (cryo-EM) to stabilize the host-guest structure and resolve the atomic surface of zeolitic imidazolate framework (ZIF-8) and its interaction with guest CO2 molecules. We image step-edge sites on the ZIF-8 surface that provides insight to its growth behavior. Furthermore, we observe two distinct binding sites for CO2 within the ZIF-8 pore, which are predicted by density functional theory (DFT) to be energetically favorable. This CO2 insertion induces an apparent ~3% lattice expansion along the <002> and <011> directions of the ZIF-8 unit cell. The ability to stabilize and preserve host-guest chemistry opens a rich materials space for scientific exploration and discovery using cryo-EM.

    View details for DOI 10.1016/j.matt.2019.06.001

    View details for PubMedID 34104881

    View details for PubMedCentralID PMC8184120