Radiometric X-Calibration Analysis from OCO-3 and OCO-2 Simultaneous Nadir Overpasses
No abstract provided
Yu, Shanshan↗
Engineering topics
Yu, Shanshan
Publications and source records attributed to Yu, Shanshan.
miR-23b Ameliorates nonalcoholic steatohepatitis by targeting Acyl-CoA thioesterases 4
Non-alcoholic fatty liver disease (NAFLD) and its more advanced stages, Non-alcoholic steatohepatitis and Cirrhosis, are the most common liver diseases in the worldwide, especially in developing countries. NAFLD is distinguished by the accumulation of triglycerides within hepatocytes. An increasing body of evidence suggests that hepatic MicroRNAs play an important role in NAFLD by controlling lipid metabolism, inflammation, and fibrosis. However, the precise causative functions of miRNA in NAFLD remain unknown. Here, we discovered that mice lacking MicroRNA-23b developed NAFLD-like phenotypes such as increased serum triglyceride and lipid droplet accumulation. In db/db mice fed a high fat diet, MicroRNA-23b overexpression reduced liver weight and alleviated liver inflammation, apoptosis, and fibrosis. MicroRNA-23b regulates the acyl-CoA metabolic process via Acyl-CoA thioesterase 4 (Acot4), which interacts with Acetyl CoA Carboxylase (ACC), according to the RNA-seq analysis.
60 APPLIED LIFE SCIENCES↗
Radiometric Calibration Analysis from OCO-3 and OCO-2 Simultaneous Nadir Overpasses
No abstract provided
Crisp, David↗
Static and Dynamic Inputs to OCO-2/3 Calibration: Preflight & Inflight Combined, Coefficients Updated Weekly
No abstract provided
Maxwell, Stephen↗
Oco-2 Calibration Refinement Across Versions And Plans For Oco-3
The third major reprocessing campaign for the Orbiting Carbon Observatory 2 mission is underway. With each release, several aspects of instrument calibration were improved. An onboard lamp tracks relative gain degradation, but ages too quickly to track absolute scaling. The most significant changes between builds were evolving assumptions about the stability of the solar calibrator. For the newest build, the trend in lunar measurements over a 4.5-year time series was applied. Another significant change was to expand a list of detector outliers via review of dark, lamp, and science measurements. More subtle adjustments to stray light and spectral dispersion were also performed. The techniques developed for OCO-2 are being applied to the Orbiting Carbon Observatory 3, which completed in-orbit checkout in August 2019. OCO-3 does not have a solar calibrator, and will need to constrain lamp aging via secondary lamps and comparison to other satellites.
Rosenberg, Rob↗
Direct retrieval of isoprene from satellite-based infrared measurements
Isoprene is the atmosphere’s most important non-methane organic compound, with key impacts on atmospheric oxidation, ozone, and organic aerosols. In-situ isoprene measurements are sparse, and satellite-based constraints have employed an indirect approach using its oxidation product formaldehyde, which is affected by non-isoprene sources plus uncertainty and spatial smearing in the isoprene-formaldehyde relationship. Direct global isoprene measurements are therefore needed to better understand its sources, sinks, and atmospheric impacts. Here we show that the isoprene spectral signatures are detectable from space using the satellite-borne Cross-track Infrared Sounder (CrIS), develop a full-physics retrieval methodology for quantifying isoprene abundances from these spectral features, and apply the algorithm to CrIS measurements over Amazonia. The results are consistent with model output and in-situ data, and establish the feasibility of direct global space-based isoprene measurements. Finally, we demonstrate the potential for combining space-based measurements of isoprene and formaldehyde to constrain atmospheric oxidation over isoprene source regions.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Protein engineering of a ubiquitin-variant inhibitor of APC/C identifies a cryptic K48 ubiquitin chain binding site
Ubiquitin (Ub)-mediated proteolysis is a fundamental mechanism used by eukaryotic cells to maintain homeostasis and protein quality, and to control timing in biological processes. Two essential aspects of Ub regulation are conjugation through E1-E2-E3 enzymatic cascades and recognition by Ub-binding domains. An emerging theme in the Ub field is that these 2 properties are often amalgamated in conjugation enzymes. In addition to covalent thioester linkage to Ub’s C terminus for Ub transfer reactions, conjugation enzymes often bind noncovalently and weakly to Ub at “exosites.” However, identification of such sites is typically empirical and particularly challenging in large molecular machines. In this work, studying the 1.2-MDa E3 ligase anaphase-promoting complex/cyclosome (APC/C), which controls cell division and many aspects of neurobiology, we discover a method for identifying unexpected Ub-binding sites. Using a panel of Ub variants (UbVs), we identify a protein-based inhibitor that blocks Ub ligation to APC/C substrates in vitro and ex vivo. Biochemistry, NMR, and cryo-electron microscopy (cryo-EM) structurally define the UbV interaction, explain its inhibitory activity through binding the surface on the APC2 subunit that recruits the E2 enzyme UBE2C, and ultimately reveal that this APC2 surface is also a Ub-binding exosite with preference for K48-linked chains. The results provide a tool for probing APC/C activity, have implications for the coordination of K48-linked Ub chain binding by APC/C with the multistep process of substrate polyubiquitylation, and demonstrate the power of UbV technology for identifying cryptic Ub-binding sites within large multiprotein complexes.
59 BASIC BIOLOGICAL SCIENCES↗
Selenoprotein S protects against adipocyte death through mediation of the IRE1α-sXBP1 pathway
As the most conserved branch of the unfolded protein response (UPR), the inositol-requiring enzyme 1a (IRE1a)/X-box binding protein 1 (XBP1) pathway plays crucial roles in cell survival and cell death by upregulating UPR-associated genes involved in protein entry into the endoplasmic reticulum (ER) and ER-associated degradation (ERAD). Selenoprotein S (SelS) is localized to the ER membrane and involved in ERAD. Although SelS plays an important role in restoring ER stress, the SelS-dependent protective mechanisms against cell death remain unclear. Here, using an inducible SelS knockdown (KD) 3T3-L1 cell model, we showed that SelS KD resulted adipocyte death, which was associated with imbalance of the Bcl-2 family members. Furthermore, SelS KD decreased spliced XBP1 (sXBP1), increased IRE1α and p-JNK, suggesting a role of SelS in the modulation of the IRE1α-sXBP1 pathway. Moreover, adipocyte death induced by SelS suppression can be inhibited by overexpression of sXBP1. Thus, it is proposed that SelS promotes cell survival through the IRE1α-XBP1 signaling pathway.
60 APPLIED LIFE SCIENCES↗