Propeptide-Mediated Allosteric Regulation of Xylanase Xyl-1: An Integrated Experimental and Computational Analysis.

Most GH11 family endo-ß-1,4-xylanases contain a propeptide region linked to the N-terminal region. The mechanistic basis of this region harboring key regulation information for enzyme function, however, remains poorly understood. We reported an investigation on the allosteric regulation mechanism of the propeptide based on biochemical characterization, molecular dynamics simulations, and evolutionary analysis. We discovered that the mutant of truncated propeptide shows a remarkably increased thermal stability (melting temperature increased by 11.5 °C) and catalytic efficiency (1.7-fold kcat/Km value of wild type). Molecular dynamics simulations reveal that long-range fluctuations in the propeptide lead to a conformational perturbation in the catalytic pocket and the thumb region. The probability of sampling the active conformation during the glycosylation step is reduced (i.e., catalytic efficiency). In-depth sequence analysis indicates that the propeptide has a strong plasticity and degeneration trend, and propeptide truncation experiments of the homologous enzyme XynB validated the feasibility of the truncation strategy. This work reveals the role of GH11 family propeptides in functional regulation and provides a straightforward and practical method to increase the robustness of GH11 family xylanases.

Expression of PD-1 on CD4+ Tumor-Infiltrating Lymphocytes in Tumor Microenvironment Associated with Pathological Characteristics of Breast Cancer.

OBJECTIVE: This study aimed to investigate the correlation of CD4+/PD-1+ or CD4+/PD-1- tumor-infiltrating lymphocytes with pathological characteristics in breast cancer patients. METHODS: A cross-sectional study consecutively recruited 133 patients with invasive ductal breast cancer. The expression of CD4, programmed cell death protein 1 (PD-1), CK7, CK20, E-cadherin, or Ki-67 was detected by immunohistochemistry. The associations between CD4+/PD-1+ or CD4+/PD-1- tumor-infiltrating lymphocytes and pathological characteristics were evaluated. RESULTS: Elderly patients intended to have a lower level of CD4+/PD-1- tumor-infiltrating lymphocytes (p < 0.05). Patients with positive E-cadherin expression had higher median cell counts of CD4+/PD-1- tumor-infiltrating lymphocytes than patients with negative E-cadherin expression (30/HPF versus 10/HPF, p < 0.05). Counts of CD4+/PD-1+ tumor-infiltrating lymphocytes had a significant correlation with Ki-67 index that the correlation coefficient was 0.29 (p = 0.001). Positive CK20 expression was related to a higher level of CD4+/PD-1- tumor-infiltrating lymphocytes than negative CK20 expression (73/HPF versus 30/HPF, p < 0.05). CONCLUSION: CD4+/PD-1+ or CD4+/PD-1- tumor-infiltrating lymphocytes showed diverse association with pathological features of breast cancer. CD4+/PD-1+ tumor-infiltrating lymphocytes had a significant relationship with Ki-67 expression whereas CD4+/PD-1- tumor-infiltrating lymphocytes had a significant relationship with E-cadherin expression. Further studies are warranted to explore the immunomodulatory effects of phenotypes of CD4+ T cell subsets in breast cancer.

The identification of miR-375 as a potential biomarker in distal gastric adenocarcinoma.

MicroRNAs (miRNAs) are endogenous small noncoding RNAs that negatively regulate gene expression at the posttranscriptional level and play an important role in carcinogenesis. Herein, we characterized the global expression of miRNA in distal gastric adenocarcinomas and determined if circulating miRNAs could be used as biomarkers for distal gastric adenocarcinoma. We used a microarray screening system to detect dysregulated miRNAs in distal gastric adenocarcinoma tissues. The expression of a subset of five aberrantly expressed miRNAs (miR-375, -196b, -204, -18b, and -93) were further quantified in an independent set of clinical samples of distal gastric adenocarcinoma by real-time quantitative RT-PCR (rt-qRT-PCR). We also used rt-qRT-PCR to investigate the expression levels of putative miRNA biomarkers in serum and tumor cell lines. In our study, the expression of a subset of microRNAs was altered in distal gastric adenocarcinoma compared to normal tissue, miR-375 was significantly downregulated in distal gastric adenocarcinoma tissues, to a level that was significantly lower than cardia adenocarcinoma (p < 0.05). The circulating serum levels of miR-375 in patients who had distal gastric adenocarcinoma were also much lower than normal controls (p < 0.001). As a biomarker, miR-375 yielded a receiver operating characteristic area under the curve of 0.835. The specificity and sensitivity was 80% and 85%, respectively, in the discrimination of distal gastric adenocarcinoma from control, at a normalized cutoff of 0.218. The expression of miR-375 was downregulated both in distal gastric adenocarcinoma tissues and serum of patients with distal gastric adenocarcinoma. These data suggest miR-375 is a potential biomarker for distal gastric adenocarcinoma.

A simple and efficient protocol for large-scale preparation of three flavonoids from the flower of Daphne genkwa by combination of macroporous resin and counter-current chromatography.

In this paper, macroporous resin column chromatography and counter-current chromatography (CCC) were applied for large-scale preparative separation of three flavonoids from the flower of Daphne genkwa, a famous Chinese medicinal herb. Nine kinds of resins were investigated by adsorption and desorption tests and D101 macroporous resin was selected for the first cleaning-up, in which 40% aqueous ethanol was used to remove the undesired constituents and 90% aqueous ethanol was used to elute the targets. The crude extract after the first step was directly subjected to the preparative CCC purification using the solvent system composed of n-hexane-ethyl acetate-methanol-water (4:5:4:5, v/v). The compounds apigemin (823 mg), 3-hydroxyl-genkwanin (842 mg) and genkwanin (998 mg) with the purities of 98.79, 97.71 and 93.53%, respectively, determined by HPLC were produced from 3-g crude extract only in one CCC run. Their chemical structures were identified by MS, UV and the standards.

[Ecological mechanisms of the effects of vegetation restoration on the controls of non-point source pollution on barren tableland in Dianchi Watershed of China].

Surface runoff, soil erosion and the leaching of the different forms of nitrogen and phosphorus were observed and the hygroscopic volume of branch and leaves of all plant species and soil penetration were determined to understand the ecological mechanisms of the effects of vegetation restoration on the controls of non-point source pollution on barren tableland in Dianchi Watershed of China. Results indicated that there were significantly relationships between surface runoff volume and the output of non-point pollution matters. The different manmade vegetation systems, consisted respectively of A. nepalensis, A. mearnsii, R. pseudoacacia and V. zizanioides clump, had shown the different potentials to control the leaching of TN, TP, soluble TP, soluble TN. Strong hygroscopic functions of leaves and branch was able to promote the interception of rainfalls and give rise to the less of surface runoff. The leaves, that were small, with low water content, no leathery and have rough face and epidermal wools, were able to got the highly ratio of the hygroscopic volume to above ground fresh standing crops and strengthened the interception of forest canopy. Preparing soil, growth of root system of plant and the natural recovery of vegetation at the gap of trees enhanced surface runoff penetration, as lightened the surface runoff leaching the different forms of nitrogen, phosphorus of soil on the stands. The leaching of different forms of nitrogen and phosphorus went down with the controls of surface runoff in different stands as well.

[Treatment of proliferative lupus nephritis with leflunomide and steroid: a prospective multi-center controlled clinical trial].

OBJECTIVE: Leflunomide (LEF) is a selective inhibitor of de novo pyrimidine synthesis, currently used in the treatment of rheumatoid arthritis. To evaluate the efficacy and safety of LEF in the treatment of proliferative lupus nephritis, a prospective multi-center controlled clinical trial was conducted. METHODS: Patients with biopsy-confirmed proliferative lupus nephritis were recruited. Patients of recent onset who had not used any immunosuppressive drug were given either oral LEF (group A) or IV cyclophosphamide (group B); relapsed patients who had received immunosuppressive therapy 3 months before were given LEF (group C). Efficacy and safety were evaluated at 6 months after treatment. RESULTS: Total 51 patients were enrolled, 4 patients withdrew due to adverse events. For those initial treated patients, total response rate were 80% in group A and 75% in group B, complete remission rate were 40% and 25% respectively, not statistically different. Renal parameters (proteinuria, serum albumin and serum creatinine) and systemic lupus erythematosus disease activity index (SLEDAI) improved similarly in both groups. For 14 relapsed patients, total response rate was 60% and complete remission rate was 6.7%. Major adverse events reported in LEF treated patients were infection and alopecia. Herpes zoster was the most often type among infectious events, and one case of severe lung infection was reported. CONCLUSION: LEF combined with steroid was effective in the induction therapy of proliferative lupus nephritis. LEF was generally well-tolerated, its efficacy in maintenance therapy and long-term safety remains to be clarified.

[Study on abnormality and regulation of T-lymphocyte subsets in peripheral blood of rheumatoid arthritis patients].

OBJECTIVE: To investigate the change of T-lymphocyte subsets in peripheral blood of rheumatoid arthritis (RA) patients and analyze the effects of Fuzheng Qubi Decoction (FZQBD) on T-cell subsets. METHODS: Thirty RA patients were randomly divided into two groups, and treated with FZQBD or western medicine combination therapy respectively for one month, the percentage of peripheral CD3+, CD4+, CD8+ as well as the serum IgG and IgA levels were determined. RESULTS: The percentage of peripheral CD4+, CD4+/CD8+ ratio, IgG and IgA levels increased significantly (P < 0.001) in RA patients before treatment. After 1 month of FZQBD treatment, the CD4+/CD8+ ratio decreased obviously (P < 0.05). CONCLUSION: Abnormal cellular immunity exists in RA patients, FZQBD could adjust the abnormal T-lymphocyte subsets to normalize it.