Intercellular and supracellular communications through plasmodesmata are involved in vital processes for plant development and physiological responses. Micro- and macromolecules, including hormones, RNA, and proteins,...Intercellular and supracellular communications through plasmodesmata are involved in vital processes for plant development and physiological responses. Micro- and macromolecules, including hormones, RNA, and proteins, serve as biological information vectors that traffic through the plasmodesmata between cells. Previous studies demonstrated that the plasmodesmata are elaborately regulated, whereby a long queue of multiple signaling molecules forms. However, the mechanism by which these signals are coupled or coor- dinated in terms of simultaneous transport in a single channel remains a puzzle. In the last few years, several phytohormones that could function as both non-cell-autonomous signals and plasmodesmal regulators have been disclosed. Plasmodesmal regulators such as auxin, salicylic acid, reactive oxygen species, gibberellic acids, chitin, and jasmonic acid could regulate intercellular trafficking by adjusting plasmodesmal permeability. Here, callose, along with β-glucan synthase and β-glucanase, plays a critical role in regulating plasmodesmal permeability. Interestingly, most of the previously identified regulators are capable of diffusing through the plasmodesmata. Given the small sizes of these molecules, the plasmo- desmata are prominent intercellular channels that allow diffusion-based movement of those signaling molecules. Obviously, intercellular communication is under the control of a major mechanism, named a feedback loop, at the plasmodesmata, which mediates complicated biological behaviors. Prospective research on the mechanism of coupling micromolecules at the plasmodesmata for developmental signaling and nutrient provision will help us to understand how plants coordinate their development and photosynthetic assimilation, which is important for agriculture.展开更多
OBJECTIVE: To verify whether the extracellular domain of kinase domain region (KDR) has anti-angiogenesis activity in vivo. METHODS: cDNA was cloned into adeno-associated virus (AAV) vector pSNAV and transfected to ba...OBJECTIVE: To verify whether the extracellular domain of kinase domain region (KDR) has anti-angiogenesis activity in vivo. METHODS: cDNA was cloned into adeno-associated virus (AAV) vector pSNAV and transfected to baby hamster kidney (BHK) cells. Recombinant AAV was obtained from the cell culture supernatant after adding helper virus. Recombinant AAV-infected human bladder cancer EJ cell line (EJ cells) were injected subcutaneously into Balb-c nude mice. Tumor specimens were removed from the mice, paraffin-embedded and sliced, then stained by immunohistochemistry. Microvessel density (MVD) was determined under a microscope. RESULTS: The tumor volume developed by EJ cells transfected with the extracellular domain of KDR was significantly smaller (1.70 +/- 0.18 cm(3)) compared with that in the control (5.62 +/- 0.67 cm(3)) (P展开更多
RNA viruses cause a multitude of human diseases,including several pandemic events in the past century.Upon viral invasion,the innate immune system responds rapidly and plays a key role in activating the adaptive immun...RNA viruses cause a multitude of human diseases,including several pandemic events in the past century.Upon viral invasion,the innate immune system responds rapidly and plays a key role in activating the adaptive immune system.In the innate immune system,the interactions between pathogen-associated molecular patterns and host pattern recognition receptors activate multiple signaling pathways in immune cells and induce the production of pro-inflammatory cytokines and interferons to elicit antiviral responses.Macrophages,dendritic cells,and natural killer cells are the principal innate immune components that exert antiviral activities.In this review,the current understanding of innate immunity contributing to the restriction of RNA viral infections was briefly summarized.Besides the main role of immune cells in combating viral infection,the intercellular transfer of pathogen and host-derived materials and their epigenetic and metabolic interactions associated with innate immunity was discussed.This knowledge provides an enhanced understanding of the innate immune response to RNA viral infections in general and aids in the preparation for the existing and next emerging viral infections.展开更多
The development of a plant leaf is a meticulously orchestrated sequence of events producing a complex organ comprising diverse cell types. The reticulate class of leaf variegation mutants displays contrasting pigmenta...The development of a plant leaf is a meticulously orchestrated sequence of events producing a complex organ comprising diverse cell types. The reticulate class of leaf variegation mutants displays contrasting pigmentation between veins and interveinal regions due to specific aberrations in the development of mesophyll cells. Thus, the reticulate mutants offer a potent tool to investigate cell-type-specific developmental processes. The discovery that most mutants are affected in plastid-localized, metabolic pathways that are strongly expressed in vasculature-associated tis- sues implicates a crucial role for the bundle sheath and their chloroplasts in proper development of the mesophyll cells. Here, we review the reticulate mutants and their phenotypic characteristics, with a focus on those in Arabidopsis thali- ana. Two alternative models have been put forward to explain the relationship between plastid metabolism and meso- phyll cell development, which we call here the supply and the signaling hypotheses. We critically assess these proposed models and discuss their implications for leaf development and bundle sheath function in C3 species. The characteriza- tion of the reticulate mutants supports the significance of plastid retrograde signaling in cell development and highlights the significance of the bundle sheath in C3 photosynthesis.展开更多
文摘Intercellular and supracellular communications through plasmodesmata are involved in vital processes for plant development and physiological responses. Micro- and macromolecules, including hormones, RNA, and proteins, serve as biological information vectors that traffic through the plasmodesmata between cells. Previous studies demonstrated that the plasmodesmata are elaborately regulated, whereby a long queue of multiple signaling molecules forms. However, the mechanism by which these signals are coupled or coor- dinated in terms of simultaneous transport in a single channel remains a puzzle. In the last few years, several phytohormones that could function as both non-cell-autonomous signals and plasmodesmal regulators have been disclosed. Plasmodesmal regulators such as auxin, salicylic acid, reactive oxygen species, gibberellic acids, chitin, and jasmonic acid could regulate intercellular trafficking by adjusting plasmodesmal permeability. Here, callose, along with β-glucan synthase and β-glucanase, plays a critical role in regulating plasmodesmal permeability. Interestingly, most of the previously identified regulators are capable of diffusing through the plasmodesmata. Given the small sizes of these molecules, the plasmo- desmata are prominent intercellular channels that allow diffusion-based movement of those signaling molecules. Obviously, intercellular communication is under the control of a major mechanism, named a feedback loop, at the plasmodesmata, which mediates complicated biological behaviors. Prospective research on the mechanism of coupling micromolecules at the plasmodesmata for developmental signaling and nutrient provision will help us to understand how plants coordinate their development and photosynthetic assimilation, which is important for agriculture.
文摘OBJECTIVE: To verify whether the extracellular domain of kinase domain region (KDR) has anti-angiogenesis activity in vivo. METHODS: cDNA was cloned into adeno-associated virus (AAV) vector pSNAV and transfected to baby hamster kidney (BHK) cells. Recombinant AAV was obtained from the cell culture supernatant after adding helper virus. Recombinant AAV-infected human bladder cancer EJ cell line (EJ cells) were injected subcutaneously into Balb-c nude mice. Tumor specimens were removed from the mice, paraffin-embedded and sliced, then stained by immunohistochemistry. Microvessel density (MVD) was determined under a microscope. RESULTS: The tumor volume developed by EJ cells transfected with the extracellular domain of KDR was significantly smaller (1.70 +/- 0.18 cm(3)) compared with that in the control (5.62 +/- 0.67 cm(3)) (P
文摘RNA viruses cause a multitude of human diseases,including several pandemic events in the past century.Upon viral invasion,the innate immune system responds rapidly and plays a key role in activating the adaptive immune system.In the innate immune system,the interactions between pathogen-associated molecular patterns and host pattern recognition receptors activate multiple signaling pathways in immune cells and induce the production of pro-inflammatory cytokines and interferons to elicit antiviral responses.Macrophages,dendritic cells,and natural killer cells are the principal innate immune components that exert antiviral activities.In this review,the current understanding of innate immunity contributing to the restriction of RNA viral infections was briefly summarized.Besides the main role of immune cells in combating viral infection,the intercellular transfer of pathogen and host-derived materials and their epigenetic and metabolic interactions associated with innate immunity was discussed.This knowledge provides an enhanced understanding of the innate immune response to RNA viral infections in general and aids in the preparation for the existing and next emerging viral infections.
文摘The development of a plant leaf is a meticulously orchestrated sequence of events producing a complex organ comprising diverse cell types. The reticulate class of leaf variegation mutants displays contrasting pigmentation between veins and interveinal regions due to specific aberrations in the development of mesophyll cells. Thus, the reticulate mutants offer a potent tool to investigate cell-type-specific developmental processes. The discovery that most mutants are affected in plastid-localized, metabolic pathways that are strongly expressed in vasculature-associated tis- sues implicates a crucial role for the bundle sheath and their chloroplasts in proper development of the mesophyll cells. Here, we review the reticulate mutants and their phenotypic characteristics, with a focus on those in Arabidopsis thali- ana. Two alternative models have been put forward to explain the relationship between plastid metabolism and meso- phyll cell development, which we call here the supply and the signaling hypotheses. We critically assess these proposed models and discuss their implications for leaf development and bundle sheath function in C3 species. The characteriza- tion of the reticulate mutants supports the significance of plastid retrograde signaling in cell development and highlights the significance of the bundle sheath in C3 photosynthesis.
