Arsenic Reduces Methane Emissions from Paddy Soils: Insights from Continental Investigation and Laboratory Incubations.

Arsenic (As) contamination and methane (CH4) emissions co-occur in rice paddies. However, how As impacts CH4 production, oxidation, and emission dynamics is unknown. Here, we investigated the abundances and activities of CH4-cycling microbes from 132 paddy soils with different As concentrations across continental China using metagenomics and the reverse transcription polymerase chain reaction. Our results revealed that As was a crucial factor affecting the abundance and distribution patterns of the mcrA gene, which is responsible for CH4 production and anaerobic CH4 oxidation. Laboratory incubation experiments showed that adding 30 mg kg-1 arsenate increased 13CO2 production by 10-fold, ultimately decreasing CH4 emissions by 68.5%. The inhibition of CH4 emissions by As was induced through three aspects: (1) the toxicity of As decreased the abundance and activity of the methanogens; (2) the adaptability and response of methanotrophs to As is beneficial for CH4 oxidation under As stress; and (3) the more robust arsenate reduction would anaerobically consume more CH4 in paddies. Additionally, significant positive correlations were observed between arsC and pmoA gene abundance in both the observational study and incubation experiment. These findings enhance our understanding of the mechanisms underlying the interactions between As and CH4 cycling in soils.

Correlation between red blood cell distribution width and cardiovascular events in the patients receiving peritoneal dialysis: A Strobe-compliant article.

There are few studies on the correlation between red blood cell distribution width (RDW) and cardiovascular events in the patients receiving peritoneal dialysis (PD). We explored the correlation between RDW and cardiovascular events in PD patients and possible mechanism.A total of 138 PD patients were divided into RDW < 15% group (n = 104) and RDW ≥ 15% group (n = 34).The levels of serum C-reactive protein (CRP) [3.05 (0.79, 15.30) mg/L vs 2.15 (1.00, 6.50) mg/L] and parathyroid hormone (PTH) [260.0 (192.7, 352.6) ng/L vs 200.7 (118.0, 319.7) ng/L] were significantly higher, but the levels of serum albumin [30.65 (27.4,32.8) g/L vs 32.3 (29.25,34.95) g/L], prealbumin [(299 ±â€Š96) g/L vs (346 ±â€Š86) g/L], triglyceride [1.24 (0.72, 1.50) mmol/L vs 1.42 (1.12,1.84) mmol/L], and transferrin saturation [27.9 (16.4, 43.6)% vs 37.8 (23.3, 57.2)%] were significantly lower in the RDW ≥ 15% group than in the RDW < 15% group (all P < 0.05). The RDW was negatively correlated with albumin (r = - 0.258, P = 0.002), prealbumin (r = -0.236, P = 0.005), and triglyceride (r = -0.194, P = 0.023), but was positively correlated with CRP level (r = 0.174, P = 0.041). The incidence of cardiovascular events was significantly higher in the RDW ≥ 15% group (6 patients, 17.6%) than in the RDW < 15% group (6.7%) (7 patients, P < 0.01). Cox proportional hazard model showed that elevated RDW level was an independent risk factor for cardiovascular events in PD patients (HR = 1.622, 95% CI: 1.063-2.475, P = 0.025).The elevated RDW may be served as a risk factor to predict the cardiovascular events in PD patients.