Metagenomics reveals N-induced changes in carbon-degrading genes and microbial communities of tea (Camellia sinensis L.) plantation soil under long-term fertilization.

Soil organic carbon (SOC) is an important C pool of the global ecosystem and is affected by various agricultural practices including fertilization. Excessive nitrogen (N) application is an important field management measure in tea plantation systems. However, the mechanism underlying the impact of N fertilization on SOC, especially the microscopic mechanism remain unclear. The present study explored the effects of N fertilization on C-cycling genes, SOC-degrading enzymes and microbes expressing these enzymes by using a metagenomic approach in a tea plantation under long-term fertilization with different N rates. Results showed that N application significantly changed the abundance of C-cycling genes, SOC-degrading enzymes, especially those associated with labile and recalcitrant C degradation. In addition, the beta-glucosidase and chitinase-expressing microbial communities showed a significant difference under different N rates. At the phylum level, microbial taxa involved in C degradation were highly similar and abundant, while at the genus level, only specific taxa performed labile and recalcitrant C degradation; these SOC-degrading microbes were significantly enriched under N application. Redundancy analysis (RDA) revealed that the soil and pruned litter properties greatly influenced the SOC-degrading communities; pH and DOC of the soil and biomass and total polyphenol (TP) of the pruned litter exerted significant effects. Additionally, the random forest (RF) algorithm revealed that soil pH and dominant taxa efficiently predicted the beta-glucosidase abundance, while soil pH and DOC, pruned litter TP, and the highly abundant microbial taxa efficiently predicted chitinase abundance. Our study indicated that long-term N fertilization exerted a significant positive effect on SOC-degrading enzymes and microbes expressing these enzymes, resulting in potential impact on soil C storage in a perennial tea plantation ecosystem.

Long-term nitrogen addition increases denitrification potential and functional gene abundance and changes denitrifying communities in acidic tea plantation soil.

The response of soil denitrification to nitrogen (N) addition in the acidic and perennial agriculture systems and its underlying mechanisms remain poorly understood. Therefore, a long-term (12 years) field trial was conducted to explore the effects of different N application rates on the soil denitrification potential (DP), functional genes, and denitrifying microbial communities of a tea plantation. The study found that N application to the soil significantly increased the DP and the absolute abundance of denitrifying genes, such as narG, nirK, norB, and nosZ. The diversity of denitrifying communities (genus level) significantly decreased with increasing N rates. Moreover, the denitrifying communities composition significantly differed among the soils with different rates of N fertilization. Further variance partitioning analysis (VPA) revealed that the soil (39.04%) and pruned litter (32.53%) properties largely contributed to the variation in the denitrifying communities. Dissolved organic carbon (DOC) and soil pH, pruned litter's total crude fiber (TCF) content and total polyphenols to total N ratio (TP/TN), and narG and nirK abundance significantly (VIP >1.0) influenced the DP. Finally, partial least squares path modeling (PLS-PM) revealed that N addition indirectly affected the DP by changing specific soil and pruned litter properties and functional gene abundance. Thus, the findings suggest that tea plantation is a major source of N2O emissions that significantly enhance under N application and provide theoretical support for N fertilizer management in an acidic tea plantation system.

Effects of ammonium-based nitrogen addition on soil nitrification and nitrogen gas emissions depend on fertilizer-induced changes in pH in a tea plantation soil.

Tea (Camellia sinensis L.) plants have an optimal pH range of 4.5-6.0, and prefer ammonium (NH4+) over nitrate (NO3-); strong soil acidification and nitrification are thus detrimental to their growth. Application of NH4+-based fertilizers can enhance nitrification and produce H+ that can inhibit nitrification. However, how soil acidification and nitrification are interactively affected by different NH4+-based fertilizers in tea plantations remains unclear. The objective of this research was to evaluate the effect of the application of different forms and rates of NH4+-based fertilizers on pH, net nitrification rates, and N2O and NO emissions in an acidic tea plantation soil. We conducted a 35-day aerobic incubation experiment using ammonium sulphate, urea and ammonium bicarbonate applied at 0, 100 or 200 mg N kg-1 soil. Urea and ammonium bicarbonate significantly increased both soil pH and net nitrification rates, while ammonium sulphate did not affect soil pH but reduced net nitrification rates mainly due to the acidic nature of the fertilizer. We found that the effect of different NH4+-based nitrogen on soil nitrification depended on the impact of the fertilizers on soil pH, and nitrification played an important role in NO emissions, but not in N2O emissions. Overall, urea and ammonium bicarbonate application decoupled crop N preference and the form of N available in spite of increasing soil pH. We thus recommend the co-application of urease and nitrification inhibitors when urea is used as a fertilizer and nitrification inhibitors when ammonium bicarbonate is used as a fertilizer in tea plantations.

Biased Lewis Pairs: A General Catalytic Approach to Ether-Ester Block Copolymers with Unlimited Ordering of Sequences.

Polymerizing epoxides after cyclic esters remains a major challenge, though their block copolymers have been extensively studied and used for decades. Reported here is a simple catalytic approach based on a metal-free Lewis pair that addresses the challenge. When the Lewis acid is used in excess of a base, selective (transesterification-free) polymerization of epoxides occurs in the presence of esters, while selectivity toward cyclic esters is achieved by an oppositely biased catalyst. Hence, one-pot block copolymerization can be performed in both ester-first and ether-first orders with selectivity being switchable at any stage, yielding ether-ester-type block copolymers with unlimited ordering of sequences as well as widely variable compositions and architectures. The selectivity can also be switched back and forth several times to generate a multiblock copolymer. Experimental and calculational results indicate that the selectivity originates mainly from the state of catalyst-activated hydroxy species.

Evaluation of PTEN and CD4+FOXP3+ T cell expressions as diagnostic and predictive factors in endometrial cancer: A case control study.

To evaluate the potential role of Pten and CD4FOXP3 T cells in prognosis from endometrial cancer.Tissue samples and clinical data were collected from 200 patients with endometrial cancer and 100 control patients with benign uterine diseases. The expressions of Pten and CD4FOXP3 T cells were quantified by immunohistochemistry and immunofluorescence. After surgery, all patients were followed up for an average of 56.3 months. Surgical effects were evaluated based on the patients' symptoms and signs. A two-sided P value < .05 was considered significant.Pten diminished and CD4FOXP3 T cells significantly accumulated with the progression of endometial cancer, in comparison to the controls. Moreover, Pten expression was negatively correlated with the count of CD4FOXP3 T cells. Pten and CD4FOXP3 T cells were correlated with clinical characteristics, including tumor stage, differentiation and associated with patients' disease-free survival.Limited data were available between the expressions of Pten and CD4FOXP3 T cells in patients with endometrial cancer. Our study findings suggested that the expressions of Pten and CD4FOXP3 T cells might become possible biomarkers for the diagnosis and prediction in endometrial cancer.

Characterization of three different classes of non-fermented teas using untargeted metabolomics.

Non-fermented teas, which are widely consumed in China, Japan, Korea, and elsewhere, have refreshing flavors and valuable health benefits. Various types of non-fermented teas look and taste similar and have no obvious differences in appearance, making their classification challenging. To date, there are very few reports about characterization and discrimination of different types of non-fermented teas. To characterize non-fermented teas and build a standard model for their classification based on their chemical composition, we employed multi-platform-based metabolomics to analyze primary and secondary metabolites in three main categories of non-fermented teas (green, yellow, and white), using 96 samples collected from China. Five hundred and ninety unique tea metabolites were identified and quantified in these three types of teas. Moreover, a partial least squares discriminant analysis (PLS-DA) model was established based on metabolomics data, in order to classify non-fermented teas into these three classes. Furthermore, our results speculate that the health benefits (e.g., antioxidant content) of these three types of non-fermented tea differ primarily because of variation in their metabolic components (e.g., ascorbate, vitexin).

[Clinical effect of minimally invasive technique on the treatment of osteoporotic humeral shaft fractures in elderly patients with locking plates].

OBJECTIVE: To explore the clinical effect of minimally invasive technique combined with locking plates for the treatment of osteoporotic humeral shaft fractures in elderly patients. METHODS: From July 2012 to December 2016, 26 patients were treated by minimally invasive technique combined with the locking plate for osteoporotic humeral shaft fractures, including 10 males and 16 females, ranging in age from 61 to 81 years old, with an average of 70.3 years old. The T-score of mean bone density was -2.74. All 26 patients had closed fractures, including 6 cases of type A, 7 cases of type B and 13 cases of type C. All patients were followed up for 12 months after surgery, and the Constant shoulder joint score and Mayo elbow score were calculated before surgery and 12 months after surgery. RESULTS: All 26 patients were followed up, and the duration ranged from 12 to 16 months, with an average of 13.2 months. All fractures healed within 16 weeks, with an average healing time of 14.3 weeks. The average Constant shoulder joint score before surgery and 12 months after surgery was 54.61±2.09, 88.50±2.47. The average score of Mayo elbow joint before surgery and 12 months after surgery was 58.19±2.74, 90.30±2.16. CONCLUSIONS: The shoulder and elbow joint function of elderly patients with osteoporotic humeral fractrues treated with minimally invasive technology combined with locking plate recovered well postoperatively. It is an effective method for the treatment of osteoporotic humeral shaft fractures in elderly patients.

Early channel transurethral resection of the prostate for patients with urinary retention after brachytherapy.

OBJECTIVE: It is recommended that transurethral resection of the prostate (TURP) after brachytherapy should not be performed at an early stage after implantation. Herein we report our experiences and the results of channel TURP (cTURP) within six months post-implant for patients with refractory urinary retention. METHODS: One hundred and ninety patients with localized prostate cancer of clinical stages T1c to T2c were treated by brachytherapy as monotherapy at our institution from February 2009 to July 2013. Nine patients who developed refractory urinary retention and underwent cTURP within six months after brachytherapy were retrospectively reviewed and analyzed. RESULTS: The median interval between prostate brachytherapy and cTURP was three months (range 1.5 to 5.0 months). There were no intraoperative or postoperative complications and no incontinence resulting from the surgery. All urinary retention was relieved per the American Brachytherapy Society urinary symptom score. With a mean follow-up time of 16 months (range 6 to 26 months) after cTURP, no patient experienced biochemical recurrence. The mean serum prostate-specific antigen (PSA) of the patients who underwent cTURP was 0.42 ng/ml (range 0.08 to 0.83 ng/ml) at the end of their follow-up. CONCLUSIONS: Early cTURP was found to be safe and effective in relieving urinary retention after brachytherapy and could be performed without compromising its therapeutic efficacy.