Regulating Quality for Export: Evidence from an Agricultural Export Promotion Program in Chin

Attention toward quality has been exacerbated by the recent significant increase in the demand for high quality products. Among firms trading internationally, quality shocks about one firm’s products may damage the group’s reputation. The ongoing debate on how government interventions in food safety capacity can address these issues. This study examines the effectiveness of China’s Export Quality and Safety Demonstration (EQSD) program, a policy initiative designed to improve products’ quality in the agricultural sector by imposing strict regulations during domestic agri-food value chain. Utilizing firm-product-destination level data from 2009 to 2015, we employ a difference-in-differences approach to evaluate the program’s impact on exports. Our findings reveal that EQSD significantly enhances export performance, with heterogeneous effects across different ownership types, various products and counties. Furthermore, the program’s effectiveness is more pronounced in countries with better economic development, stricter regulations, or more homogeneity. We identify three key mechanisms driving these effects: cost reduction, quality improvement and trade facilitation. Surprisingly, we found that this export promotion policy also benefits industrial upgrading. This research contributes to the literature on export promotion, NTMs and industrial upgrading, offering valuable insights for policymakers in designing targeted interventions to boost agricultural exports amid complex global trade barriers

Assay Development and Validation for Innovative Antiviral Development Targeting the N-Terminal Autoprocessing of SARS-CoV-2 Main Protease Precursors

The SARS-CoV-2 main protease (Mpro) is initially synthesized as part of polyprotein precursors that undergo autoproteolysis to release the free mature Mpro. To investigate the autoprocessing mechanism in transfected mammalian cells, we examined several fusion precursors, with the mature SARS-CoV-2 Mpro along with the flanking amino acids (to keep the native substrate sequences) sandwiched between different tags. Our analyses revealed differential proteolysis kinetics at the N- and C-terminal cleavage sites. Particularly, N-terminal processing is differentially influenced by various upstream fusion tags (GST, sGST, CD63, and Nsp4) and amino acid variations at the N-terminal P1 position, suggesting that precursor catalysis is flexible and subject to complex regulation. Mutating Q to E at the N-terminal P1 position altered both precursor catalysis and the properties of the released Mpro. Interestingly, the wild-type precursors exhibited different enzymatic activities compared to those of the released Mpro, displaying much lower susceptibility to known inhibitors targeting the mature form. These findings suggest the precursors as alternative targets for antiviral development. Accordingly, we developed and validated a high-throughput screening (HTS)-compatible platform for functional screening of compounds targeting either the N-terminal processing of the SARS-CoV-2 Mpro precursor autoprocessing or the released mature Mpro through different mechanisms of action

Agricultural exports and retaliatory trade actions: An empirical assessment of the 2018/2019 trade conflict

We estimate the ex-post agricultural trade impacts of retaliatory measures imposed by foreign countries in response to United States' Section 232 and 301 tariffs using a theoretically consistent, monthly, product line gravity equation. Retaliation led to significant US agricultural export losses of $13.5 to$18.7 billion on an annualized basis. Considerable heterogeneity exists in the average treatment effect of retaliation. First, retaliatory trade actions presented a strong within-year seasonal impact. Nearly 70% of aggregate trade losses occurred during the US's peak export marketing season. Second, U.S. trade losses were particularly pronounced on homogeneous bulk commodities, whereas product differentiation dampened the impact of retaliation. Third, with few exceptions, the counterfactually estimated direct trade losses line up well with the U.S. Department of Agriculture's (USDA) trade damage estimates for trade aid programs distributed to farmers impacted by the trade dispute. Finally, we find little evidence that U.S. exports were able to be reoriented to alternative, nonretaliating markets-an indication of high bilateral trade frictions and the destructive consequences of retaliatory trade actions.Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD); National Science Foundation of ChinaNational Natural Science Foundation of China (NSFC) [71934005, 71903090]; Office of the Chief Economist [58-0111-19-013]Published versionPriority Academic Program Development of Jiangsu Higher Education Institutions (PAPD); National Science Foundation of China, Grant/Award Numbers: 71934005, 71903090; Office of the Chief Economist, Grant/Award Number: 58-0111-19-013Public domain – authored by a U.S. government employe

High-throughput screening and characterization of novel inhibitors targeting HIV-1 protease precursor autoprocessing

Abstract HIV-1 protease (PR) is initially synthesized as part of the Gag-Pol polyprotein precursor, which undergoes temporospatially regulated autoprocessing to liberate mature PR. The free mature enzyme is the target of currently available protease inhibitors (PIs). To explore alternative therapeutic strategies, we developed a cell-based high-throughput screening (HTS) platform targeting precursor autoprocessing, screened approximately 320,000 small molecules, and identified 27 compounds that partially suppress precursor autoprocessing. A highly sensitive infectivity assay confirmed that several compounds inhibited viral infectivity in a dose-dependent manner, with EC50 values in the low micromolar range. Notably, hit compound C7 exhibited comparable potency against both wild-type and drug-resistant HIV strains, suggesting a novel mechanism of action. An initial structure–activity relationship (SAR) analysis via analog-by-catalog suggested that antiviral activity is influenced by specific chemical groups. This study provides proof of concept for an innovative drug discovery approach targeting HIV-1 PR autoprocessing as a potential strategy to combat drug resistance