RESUMEN
Plants mainly depend on both cell-surface and intracellular receptors to defend against various pathogens. The nucleotide-binding leucine-rich repeat (NLR) proteins are intracellular receptors that recognize pathogen effectors. The first NLR was cloned thirty years ago. Genomic sequencing and biotechnologies accelerated NLR gene isolation. NLR genes have been proven useful in breeding disease resistant crops. Here, we summarized the current knowledge of strategies for NLR gene isolation and provided a list of NLRs cloned in vegetables. We also discussed the mechanisms underlying NLR gene function, the challenges of NLRs in vegetable breeding and directions for future studies in vegetables.
RESUMEN
BACKGROUND AND AIMS: Recent evidences reveal that epithelial to mesenchymal transition (EMT) exacerbates the process of intestinal fibrosis. Tumor necrosis factor-like ligand 1A (TL1A) is a member of the tumor necrosis family (TNF), which can take part in the development of colonic inflammation and fibrosis by regulating immune response or inflammatory factors. The purpose of this study was to elucidate the possible contribution of TL1A in onset and progression of intestinal inflammation and fibrosis through EMT. METHODS: Colonic specimens were obtained from patients with inflammatory bowel disease (IBD) and control individuals. The expression levels of TL1A and EMT-related markers in intestinal tissues were evaluated. Furthermore, the human colorectal adenocarcinoma cell line, HT-29, was stimulated with TL1A, anti-TL1A antibody, or BMP-7 to assess EMT process. In addition, transgenic mice expressing high levels of TL1A in lymphoid cells were used to further investigate the mechanism of TL1A in intestinal fibrosis. RESULTS: High levels of TL1A expression were detected in the intestinal specimens of patients with ulcerative colitis and Crohn's disease and were negatively associated with the expression of an epithelial marker (E-cadherin), while it was positively associated with the expression of interstitial markers (FSP1 and α-SMA). Transgenic mice with high expression of TL1A were more sensitive to dextran sodium sulfate and exhibited severe intestinal inflammation and fibrosis. Additionally, the TGF-ß1/Smad3 pathway may be involved in TL1A-induced EMT, and the expression of IL-13 and EMT-related transcriptional molecules (e.g., ZEB1 and Snail1) was increased in the intestinal specimens of the transgenic mice. Furthermore, TL1A-induced EMT can be influenced by anti-TL1A antibody or BMP-7 in vitro. CONCLUSIONS: TL1A participates in the formation and process of EMT in intestinal fibrosis. This new knowledge enables us to better understand the pathogenesis of intestinal fibrosis and identify new therapeutic targets for its treatment.
Asunto(s)
Colitis/metabolismo , Transición Epitelial-Mesenquimal , Fibrosis/metabolismo , Intestinos/metabolismo , Miembro 15 de la Superfamilia de Ligandos de Factores de Necrosis Tumoral/metabolismo , Adulto , Animales , Proteína Morfogenética Ósea 7/metabolismo , Cadherinas/metabolismo , Enfermedad Crónica , Femenino , Células HT29 , Humanos , Sistema Inmunológico , Inflamación , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Persona de Mediana Edad , Reproducibilidad de los ResultadosRESUMEN
Estimates of non-point source (NPS) contribution to total water pollution in China range up to 81% for nitrogen and to 93% for phosphorus. We believe these values are too high, reflecting (a) misuse of estimation techniques that were developed in America under very different conditions and (b) lack of specificity on what is included as NPS. We compare primary methods used for NPS estimation in China with their use in America. Two observations are especially notable: empirical research is limited and does not provide an adequate basis for calibrating models nor for deriving export coefficients; the Chinese agricultural situation is so different than that of the United States that empirical data produced in America, as a basis for applying estimation techniques to rural NPS in China, often do not apply. We propose a set of national research and policy initiatives for future NPS research in China.