Investors’ Risk Preference Characteristics Based on Different Reference Point

Taking the stock market as a whole object, we assume that prior losses and gains are two different factors that can influence risk preference separately. The two factors are introduced as separate explanatory variables into the time-varying GARCH-M (TVRA-GARCH-M) model. Then, we redefine prior losses and gains by selecting different reference point to study investors’ time-varying risk preference. The empirical evidence shows that investors’ risk preference is time varying and is influenced by previous outcomes; the stock market as a whole exhibits house money effect; that is, prior gains can decrease investors’ risk aversion while prior losses increase their risk aversion. Besides, different reference points selected by investors will cause different valuation of prior losses and gains, thus affecting investors’ risk preference

Synergistic repression of the embryonic programme by SET DOMAIN GROUP 8 and EMBRYONIC FLOWER 2 in Arabidopsis seedlings

The seed maturation programme occurs only during the late phase of embryo development, and repression of the maturation genes is pivotal for seedling development. However, mechanisms that repress the expression of this programme in vegetative tissues are not well understood. A genetic screen was performed for mutants that express maturation genes in leaves. Here, it is shown that mutations affecting SDG8 (SET DOMAIN GROUP 8), a putative histone methyltransferase, cause ectopic expression of a subset of maturation genes in leaves. Further, to investigate the relationship between SDG8 and the Polycomb Group (PcG) proteins, which are known to repress many developmentally important genes including seed maturation genes, double mutants were made and formation of somatic embryos was observed on mutant seedlings with mutations in both SDG8 and EMF2 (EMBRYONIC FLOWER 2). Analysis of histone methylation status at the chromatin sites of a number of maturation loci revealed a synergistic effect of emf2 and sdg8 on the deposition of the active histone mark which is the trimethylation of Lys4 on histone 3 (H3K4me3). This is consistent with high expression of these genes and formation of somatic embryos in the emf2 sdg8 double mutants. Interestingly, a double mutant of sdg8 and vrn2 (vernalization2), a paralogue of EMF2, grew and developed normally to maturity. These observations demonstrate a functional cooperative interplay between SDG8 and an EMF2-containing PcG complex in maintaining vegetative cell identity by repressing seed genes to promote seedling development. The work also indicates the functional specificities of PcG complexes in Arabidopsis

The ER-membrane transport system is critical for intercellular trafficking of the NSm movement protein and Tomato Spotted Wilt Tospovirus

Plant viruses move through plasmodesmata to infect new cells. The plant endoplasmic reticulum (ER) is interconnected among cells via the ER desmotubule in the plasmodesma across the cell wall, forming a continuous ER network throughout the entire plant. This ER continuity is unique to plants and has been postulated to serve as a platform for the intercellular trafficking of macromolecules. In the present study, the contribution of the plant ER membrane transport system to the intercellular trafficking of the NSm movement protein and Tomato spotted wilt tospovirus (TSWV) is investigated. We showed that TSWV NSm is physically associated with the ER membrane in Nicotiana benthamiana plants. An NSm-GFP fusion protein transiently expressed in single leaf cells was trafficked into neighboring cells. Mutations in NSm that impaired its association with the ER or caused its mis-localization to other subcellular sites inhibited cell-to-cell trafficking. Pharmacological disruption of the ER network severely inhibited NSm-GFP trafficking but not GFP diffusion. In the Arabidopsis thaliana mutant rhd3 with an impaired ER network, NSm-GFP trafficking was significantly reduced, whereas GFP diffusion was not affected. We also showed that the ER-to-Golgi secretion pathway and the cytoskeleton transport systems were not involved in the intercellular trafficking of TSWV NSm. Importantly, TSWV cell-to-cell spread was delayed in the ER-defective rhd3 mutant, and this reduced viral infection was not due to reduced replication. On the basis of robust biochemical, cellular and genetic analysis, we established that the ER membrane transport system serves as an important direct route for intercellular trafficking of NSm and TSWV

Symbiotic Bacteria Regulating Insect–Insect/Fungus/Virus Mutualism

Bacteria associated with insects potentially provide many beneficial services and have been well documented. Mutualism that relates to insects is widespread in ecosystems. However, the interrelation between “symbiotic bacteria” and “mutualism” has rarely been studied. We introduce three systems of mutualism that relate to insects (ants and honeydew-producing Hemiptera, fungus-growing insects and fungi, and plant persistent viruses and vector insects) and review the species of symbiotic bacteria in host insects, as well as their functions in host insects and the mechanisms underlying mutualism regulation. A deeper understanding of the molecular mechanisms and role of symbiotic bacteria, based on metagenomics, transcriptomics, proteomics, metabolomics, and microbiology, will be required for describing the entire interaction network

Investors' Risk Preference Characteristics Based on Different Reference Point

Taking the stock market as a whole object, we assume that prior losses and gains are two different factors that can influence risk preference separately. The two factors are introduced as separate explanatory variables into the time-varying GARCH-M (TVRA-GARCH-M) model. Then, we redefine prior losses and gains by selecting different reference point to study investors' time-varying risk preference. The empirical evidence shows that investors' risk preference is time varying and is influenced by previous outcomes; the stock market as a whole exhibits house money effect; that is, prior gains can decrease investors' risk aversion while prior losses increase their risk aversion. Besides, different reference points selected by investors will cause different valuation of prior losses and gains, thus affecting investors' risk preference