Browsing by Author "Jin, Jing"

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    Characterization of Oxidosqualene Cyclases in Brassicaceae: the ABCs (Arabidopsis, Brassica and Capsella)
    (2019-10-23) Jin, Jing; Matsuda, Seiichi P. T.
    One major class of plant secondary metabolites is the triterpenes, whose biosynthesis from oxidosqualene is catalyzed by oxidosqualene cyclases (OSCs). This thesis describes the characterization of OSCs from plants within the Brassicaceae family, which include the model species Arabidopsis thaliana and Capsella rubella as well as the crop species Brassica rapa and Brassica oleracea. Detailed product profiles of those cyclases are combined with phylogenetic analysis, synteny analysis, active-site prediction, plant tissue extraction and transcriptome analysis to explore enzyme mechanisms and evolutionary relationships within the OSC family. First, detailed product profiles are constructed for four Arabidopsis thaliana OSCs. Those cyclases exemplify the range of product specificity among OSCs, ranging from the 94% specific At PEN4 to the multi-functional cyclase At LUP5 which makes two major products at similar levels. Despite their varying product specificity, all those OSCs form many minor products. Next, the characterization of three OSCs from Brassica species is detailed. Bra032185 was determined to be an astertarone A synthase, which is the first reported OSC with 6/6/6/5 20R stereospecificity. Bra039929 is the first reported euphol synthase and is another 6/6/6/5 20R specific cyclase. In addition, Bol021540 was amplified from broccoli seedling RNAs and it was determined to be a mixed-amyrin synthase. Those results were combined with Brassica plant extraction results to explore the triterpene biosynthesis in this species. Lastly, the complete characterization of all Capsella rubella OSCs is described. The triterpene biosynthetic capability of this plant includes one cycloartenol synthase, five functional OSCs in the secondary metabolism and one pseudogene. The only secondary metabolic OSC conserved between A. thaliana and C. rubella is camelliol C synthase (LUP3). In addition, three C. rubella cyclases show similarity to their A. thaliana counterparts but different products are made. Overall, the comparison of OSCs across species illustrates the fast divergence of plant secondary metabolism and explores OSC evolution among the Brassicaceae family. The OSC family showcases rapid enzyme functional evolution as evident by neofunctionalization and convergent evolution, and thus it can be a valuable model for enzyme evolution studies.
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    Three Essays on CEO's Impression Management
    (2016-04-22) Jin, Jing; Hoskisson, Robert E; Li, Haiyang
    Impression management has been used by organizations, especially their top executives, in various situations so that they could influence the image of the organizations or top executives in the eyes of external audiences. An impression management process involves two parties, actors, who initiate impression management tactics, and targets, who give feedback to actors suggesting whether impression management is successful or not. My three essays intend to address different questions involved in this process. In particular, essay one addresses the question: how CEOs do impression management during mergers and acquisitions announcements? Given that acquirer firms tend to receive negative stock market reactions, I argue that CEOs have two different approaches to do impression management in this situation using strategic noise. More specifically, CEOs could either release positive strategic noise to offset potential negative effect, or release negative strategic noise to obscure the causal link between the acquisition announcements and negative stock market reactions. I find empirical support for my hypotheses based on zero-inflated negative binomial models. Essay two addresses the question: how impression management works when there are multiple target audiences? Does one target’s reaction influence another? To address these questions, I examine whether CEOs could adopt impression management tactics to influence analysts’ and investors’ reactions, and whether their reactions could ultimately affect boards’ decisions on CEO dismissal in the context of financial restatements. I find that CEOs tend to release more news after financial restatements that could improve investors’ and analysts’ reactions. Improved analysts’ reactions could reduce CEO dismissal likelihood after financial restatements. Essay three focuses on a different question: whether comparable firms’ situations affect the effectiveness of focal firm’s impression management? This question is especially critical when firms desire to engage in impression management in anticipation of negative news. I developed a theoretical model to address this question. In particular, I categorize all possible situations into four different scenarios based on the dimensions of consistency information and consensus information. I further discuss and compare different causal attribution strategies in each scenario. To achieve successful impression management, I suggest that firms provide explanations that are consistent with external audiences’ perceptions. In addition, beyond this objective information, external audiences’ reactions are also affected by their emotional and biased beliefs.
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    Who do you take to tango? Examining pairing mechanisms between underwriters and initial public offering firms in a nascent stock market
    (Wiley, 2022) Zhang, Yan Anthea; Chen, Jin; Li, Haiyang; Jin, Jing
    Previous studies on initial public offerings (IPOs) in mature stock markets have documented that high-reputation underwriters primarily work with high-quality firms and vice versa—that is, they are paired through a quality-matching mechanism. We propose that in a nascent stock market, a pricing mechanism may also play a role, through which pricing (the underwriting fee) sets the pairing. We examine these two mechanisms in the context of China's ChiNext stock exchange, which was launched in 2009 and experienced dramatic regulatory improvements in 2012–2013. With data on IPOs in 2009–2017, we find evidence to support the pricing mechanism's effect before the regulatory improvements and the quality-matching mechanism's effect after the improvements. We contribute to the literature by developing an evolutionary view on the pairing mechanisms between important capital market participants. Managerial Summary In a mature stock market, underwriter reputation signals the underlying quality of initial public offering (IPO) firms to external investors because high-reputation underwriters primarily work with high-quality IPO firms and vice versa. We find that in a nascent stock market before the market experiences regulatory improvements, underwriters and IPO firms are paired through a pricing mechanism. That is, underwriters with higher reputation charge higher underwriting fees, and IPO firms with lower quality pay higher fees. Since the pricing mechanism rather than the quality-matching mechanism sets the pairing, underwriter reputation does not have a signaling effect. Instead, we find that higher underwriting fees signal lower quality of IPO firms. Our findings shed important insights on how market participants are paired in other nascent markets, nascent technology fields and industries.