Comprehensive analysis of metal(loid)s and associated metal(loid) resistance genes in atmospheric particulate matter.

Despite global concerns about metal(loid)s in atmospheric particulate matter (PM), the presence of metal(loid) resistance genes (MRGs) in PM remains unknown. Therefore, we conducted a comprehensive investigation of the metal(loid)s and associated MRGs in PMs in two seasons (summer and winter) in Xiamen, China. According to the geoaccumulation index (Igeo), most metal(loid)s, except for V and Mn, exhibited enrichment in PM, suggesting potential anthropogenic sources. By employing Positive Matrix Factorization (PMF) model, utilizing a dataset encompassing both total and bioaccessible metal(loid)s, along with backward trajectory simulations, traffic emissions were determined to be the primary potential contributor of metal(loid)s in summer, whereas coal combustion was observed to have a dominant contribution in winter. The major contributor to the carcinogenic risk of metal(loid)s in both summer and winter was predominantly attributed to coal combustion, which serves as the main source of bioaccessible Cr. Bacterial communities within PMs showed lower diversity and network complexity in summer than in winter, with Pseudomonadales being the dominant order. Abundant MRGs, including the As(III) S-adenosylmethionine methyltransferase gene (arsM), Cu(I)-translocating P-type ATPase gene (copA), Zn(II)/Cd(II)/Pb(II)-translocating P-type ATPase gene (zntA), and Zn(II)-translocating P-type ATPase gene (ziaA), were detected within the PMs. Seasonal variations were observed for the metal(loid) concentration, bacterial community structure, and MRG abundance. The bacterial community composition and MRG abundance within PMs were primarily influenced by temperature, rather than metal(loid)s. This research offers novel perspectives on the occurrence of metal(loid)s and MRGs in PMs, thereby contributing to the control of air pollution.

Effect of potassium-channel openers on the release of endothelium-derived hyperpolarizing factor in porcine coronary arteries stored in cold hyperkalemic solution.

Hyperkalemic solution is widely used to protect the myocardium during open-heart surgery or to preserve donor hearts during heart or heart/lung transplants. The inhibitory effects of hvperkalemic solution on the release of endothelium-derived hyperpolarizing factor (EDHF) of coronary arteries following deep hypothermic storage (4 degrees C) has been well studied. However, it has not been established whether potassium channel openers have protective effects on the coronary endothelial function after cold storage. This study was designed to examine this. Porcine coronary artery rings were studied in organ baths. Relaxation in response to the EDHF stimulus A23187 (nonreceptor-mediated stimulus calcium ionophore) in thromboxane A2 mimetic U46619 (30 nmol/L)-induced precontraction after incubation with hyperkalemic solution (20 mmol/L) with nicorandil (10 micromol/L) (either at 37 degrees C in the oxygenated organ chamber or at 4 degrees C in a refrigerator for 6 h) was compared with the control. There was significant difference between hyperkalemia group and hyperkalemia with nicorandil group under normothermia (p = .04). The difference was significant in the same solution between normothermia and hypothermia. After incubation in hyperkalemic solution without or with nicorandil, the A23187-induced relaxation was 32.8% +/- 9.1% and 72.6% +/- 16.9%, respectively (N = 8, p < .01). Potassium channel opener can attenuate the inhibitory effect of hyperkalemic solution on the release of EDHF after cold storage.