RESUMEN
UDP glucosyltransferase (UDPGT) catalyzes the synthesis of secondary metabolites and plant hormones to regulate plant growth and development, pathogen defense and environmental adaptability. In this study 18 members of the RcUDPGT gene family were cloned from Tibetan Rhodiola crenulata and analyzed using bioinformatics. The tissue-specific expression, abiotic stresses and plant hormones (abscisic acid, auxin, methyl jasmonate) induced expression patterns were identified by real-time quantitative PCR. The bait vector of RcUDPGT (JX228125.1) was constructed to select interacting proteins from an Arabidopsis yeast library. The results of the bioinformatics analysis revealed that RcUDPGT nucleotide sequences were about 1 400 bp and encoded 452-498 amino acids. In the primary protein sequences, C-terminal sequences were more conserved compared with N-terminal regions, which held a PSPG (plant secondary product glycosyltransferase) domain. In the tertiary structures, RcUDPGTs contained a UDP sugar donor recognition binding site. In addition, all genes had multiple phosphorylation sites. The results of qRT-PCR showed that RcUDPGTs genes were expressed in root, stem and leaf. The expression levels were regulated by low temperature/ultraviolet light and various plant hormones (ABA, IAA, MeJA), but the expression patterns were quite different among them. For example, RcUDPGT6, RcUDPGT11, and RcUDPGT17 had the highest expression in leaves and were induced by all three hormones, suggesting that the functions of these genes might be to respond to environmental changes. RcUDPGT9, RcUDPGT10, RcUDPGT14 were most abundantly expressed in roots and were significantly induced by ABA and MeJA hormones, indicating that these genes may be involved in the synthesis and accumulation of salidroside. Yeast two-hybrid results showed that RcUDPGT did not exhibit autoactivation and cell toxicity, and two significant interactional genes were identified, AtKCR1 (AT1G67730.1) and AtSNL4 (AT1G70060). The AtKCR1 gene encodes a β-ketoacyl reductase (KCR) involved in synthesis of very long chain fatty acids. The AtSNL4 gene encodes a homolog of the transcriptional repressor SIN3, which could participate in the ABA hormone signaling pathway and enhance the transcriptional repression of AP2/EREBP class factors in Arabidopsis. These results suggest that the accumulation of the secondary metabolite salidroside in Rhodiola crenulata might be affected by several regulatory mechanisms. The above results may lay the foundation for understanding the adaptive mechanism of Rhodiola crenulata in a high altitude environment and stimulate an in-depth study of the synthesis and accumulation of secondary metabolites in this species.
RESUMEN
<p><b>OBJECTIVE</b>To evaluate the initial clinical characteristics, the response to treatment, and the outcome in adult patients with Evans syndrome.</p><p><b>METHODS</b>The clinical data of 84 adult patients (20 males, 64 females) with Evans syndrome diagnosed at our center between 1984 and 2007 were retrospectively analyzed.</p><p><b>RESULTS</b>The patients were followed up for a median duration of 17.5 (0.03 - 140) months. All the patients initially received intravenous steroids with or without intravenous immunoglobulin (IVIG). Forty-seven patients were treated with corticosteroids alone initially. Complete remission (CR) and partial remission (PR) were achieved in 38 of the patients, but 92.1% of them relapsed during a median follow-up of 12 months. Twenty-eight patients who were resistant to corticosteroids therapy or with severe bleeding were subsequently administered immunosupressive agents. CR and PR were obtained in 89.3% of them. Within a median follow-up of 8 months, 84% of these patients relapsed.</p><p><b>CONCLUSIONS</b>Evans syndrome is a chronic and easy to recurrent disease, which is often refractory to conventional therapy. Treatment with combination agents might be a useful therapeutic approach to the patients.</p>