Identification of Key Residues Required for RNA Silencing Suppressor Activity of p23 Protein from a Mild Strain of Citrus Tristeza Virus.

The severe strain of citrus tristeza virus (CTV) causes quick decline of citrus trees. However, the CTV mild strain causes no symptoms and commonly presents in citrus trees. Viral suppressor of RNA silencing (VSR) plays an important role in the successful invasion of viruses into plants. For CTV, VSR has mostly been studied in severe strains. In this study, the N4 mild strain in China was sequenced and found to have high sequence identity with the T30 strain. Furthermore, we verified the functions of three VSRs in the N4 strain, and p23 was found to be the most effective in terms of local silencing suppressor activity among the three CTV VSRs and localized to both nucleus and plasmodesmata, which is similar to CTV T36 strain. Several conserved amino acids were identified in p23. Mutation of E95A/V96A and M99A/L100AA impaired p23 protein stability. Consequently, these two mutants lost most of its suppressor activity and their protein levels could not be rescued by co-expressing p19. Q93A and R143A/E144A abolished p23 suppressor activity only and their protein levels increased to wild type level when co-expressed with p19. This work may facilitate a better understanding of the pathogenic mechanism of CTV mild strains.

Reliability, validity and responsiveness of the Mandarin (Simplified) Chinese version of the EORTC QLQ-OH45 among cancer patients.

PURPOSE: The goal of our study was to evaluate the reliability, validity, responsiveness and acceptability of the Mandarin (simplified) Chinese version of the EORTC QLQ-OH45. METHODS: From October 2017 to February 2018, 393 cancer patients were enrolled from three different hospitals in China. A forward and backward translation was made to develop the Mandarin (simplified) Chinese version of EORTC QLQ-OH15. The QLQ-C30 and QLQ-OH15 questionnaires (which we have assembled and named QLQ-OH45 in this paper) were self-administered. Results were statistically analysed using SPSS 21.0. The reliability and validity tests of the questionnaires were assessed by Cronbach's α coefficient, Pearson correlation test and Mann-Whitney U tests. Responsiveness to change was measured in an independent sample of patients with head and neck cancer undergoing surgery or radiotherapy or chemotherapy. RESULTS: An acceptable internal consistency reliability for most multiple-item scales was demonstrated, as Cronbach's α coefficients were greater than 0.7 for most multiple-item scales, excepting for cognitive functioning (0.36) and oral health-related QoL functioning (0.55). All domain's test-retest reliability coefficients (r) was higher than 0.8. Multi-trait scaling analysis showed good convergent and discriminant validity. A difference in the quality of life (QoL) between older (≥65 years) and younger (<65 years) groups of patients was showed by the known-group comparisons. Low correlations were found between the scales of the QLQ-OH15 and QLQ-C30 in all areas. CONCLUSION: The Mandarin (simplified) Chinese version of QLQ-OH45 demonstrates satisfactory psychometric properties and can be used to measure the oral health-related QoL (OHRQoL) for Chinese cancer patients.