Chlorine disinfection to drinking water plays an important role in preventing and controlling waterborne disease outbreaks globally. Nevertheless, little is known about why it enriches the antibiotic resistance genes (ARGs) in bacteria after chlorination. Here, ARGs released from killed antibiotic-resistant bacteria (ARB), and culturable chlorine-injured bacteria produced in the chlorination process as the recipient, were investigated to determine their contribution to the horizontal transfer of ARGs during disinfection treatment. We discovered Escherichia coli, Salmonella aberdeen, Pseudomonas aeruginosa and Enterococcus faecalis showed diverse resistance to sodium hypochlorite, and transferable RP4 could be released from killed sensitive donor consistently. Meanwhile, the survival of chlorine-tolerant injured bacteria with enhanced cell membrane permeabilisation and a strong oxidative stress-response demonstrated that a physiologically competent cell could be transferred by RP4 with an improved transformation frequency of up to 550 times compared with the corresponding untreated bacteria. Furthermore, the water quality factors involving chemical oxygen demand (COD Mn), ammonium nitrogen and metal ions (Ca 2+ and K +) could significantly promote above transformation frequency of released RP4 into injured E. faecalis. Our findings demonstrated that the chlorination process promoted the horizontal transfer of plasmids by natural transformation, which resulted in the exchange of ARGs across bacterial genera and the emergence of new ARB, as well as the transfer of chlorine-injured opportunistic pathogen from non-ARB to ARB. Considering that the transfer elements were quite resistant to degradation through disinfection, this situation poses a potential risk to public health.
Abstract-Inflammatory responses are associated with the genesis and progression of end-organ damage (EOD) in hypertension. A role for the ␣7 nicotinic acetylcholine receptor (␣7nAChR) in inflammation has recently been identified. We tested the hypothesis that ␣7nAChR dysfunction contributes to hypertensive EOD. In both spontaneously hypertensive rats (SHRs) and rats with abdominal aorta coarctation-induced hypertension, atropine-induced tachycardia was blunted compared with normotensive controls. Both models of hypertension were associated with deficits in expression of the vesicular acetylcholine transporter and the ␣7nAChR in cardiovascular tissues. In hypertension induced by abdominal aorta coarctation, deficits in aortic vesicular acetylcholine transporter and ␣7nAChR were present both above and below the coarctation site, indicating that they were independent of the level of arterial pressure itself. Hypertension in 40-week-old SHRs was associated with cardiac and aortic hypertrophy. Morphological abnormalities consistent with EOD, along with elevated tissue levels of proinflammatory cytokines (tumor necrosis factor-␣, interleukin-1, and interleukin-6) were observed in the heart, kidney, and aorta. Chronic treatment of SHRs with the ␣7nAChR agonist PNU-282987 relieved EOD and inhibited tissue levels of proinflammatory cytokines and activation of nuclear factor B. Greater serum levels of proinflammatory cytokines and more severe damage in the heart, aorta, and kidney were seen in ␣7nAChR Ϫ/Ϫ mice subjected to 2-kidney-1-clip surgery than in wild-type mice. A deficit in the cholinergic anti-inflammatory pathway appears to contribute to the pathogenesis of EOD in models of hypertension of varying etiology. This pathway may provide a new target for preventing cardiovascular disease resulting from hypertension. (Hypertension. 2011;57:298-307.) • Online Data Supplement Key Words: acetylcholine Ⅲ ␣7 nicotinic acetylcholine receptor Ⅲ inflammation Ⅲ hypertension Ⅲ end-organ damage H ypertension is a major risk factor for myocardial infarction, heart failure, stroke, and kidney dysfunction. Endorgan damage (EOD), including cardiac hypertrophy and myocyte dysfunction, vascular remodeling, and renal lesions, is a crucial mediatory link between hypertension and the development of these cardiovascular events. 1 Therefore, a better understanding of the mechanisms leading to hypertensive EOD could provide new avenues for prevention of cardiovascular events. Inflammation is very important in the genesis and development of EOD. 2,3 Furthermore, the reninangiotensin system can contribute to EOD, at least partly by promoting inflammation. 4 -7 However, cardiovascular inflammation and EOD can also occur without renin-angiotensin system activation, 8 so other mechanisms must also operate.Recent evidence indicates that neuronal 9 -11 cholinergic systems influence inflammatory responses by controlling the release of tumor necrosis factor (TNF)-␣, interleukin-(⌱L)-1, and IL-6 and that nonneuronal acetylcholine synthesis and rele...
Our previous study showed that high levels of HMGB1 existed in rats following cardiopulmonary bypass (CPB)-induced acute lung injury (ALI) and neutralization of high-mobility group box 1(HMGB1) reduced CPB-induced ALI. However, the mechanism by which CPB increases HMGB1 secretion is unclear. Recent studies have shown that inflammasome-mediated cell pyroptosis promotes HMGB1 secretion. This study aimed to investigate the relationship between inflammasome-mediated pyroptosis and HMGB1 in CPB-related ALI. We employed oxygen-glucose deprivation (OGD)-induced alveolar macrophage (AM) NR8383 pyroptosis to measure HMGB1 secretion. We found that OGD significantly increased the levels of caspase-1 cleaved p10, IL-1β and ASC expression, caspase-1 activity and the frequency of pyroptotic AM, and promoted the cytoplasm transportation and secretion of HMGB1, which were significantly mitigated by ASC silencing or pre-treatment with glyburide (a Nlrp3 inhibitor) in AM. CPB also increased the expression levels of Nlrp3, ASC, caspase-1 P10, and IL-1β, and the percentages of AM pyroptosis in the lungs of experimental rats accompanied by increased levels of serum and bronchoalveolar lavage fluid (BALF) HMGB1. Treatment with glyburide significantly mitigated the CPB-increased ASC, caspase-1 p10 and IL-1β expression, and the percentages of AM pyroptosis in the lungs, as well as the levels of HMGB1 in serum and BALF in rats. Therefore, our data indicated that the Nlrp3/ASC-mediated AM pyroptosis increased HMGB1 secretion in ALI induced by CPB. These findings may provide a therapeutic strategy to reduce lung injury and inflammatory responses during CPB.
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