Class 1 integron in staphylococci

As a major concern in public health, methicillin-resistant staphylococci (MRS) still remains one of the most prevalent pathogens that cause nosocomial infections throughout the world and has been recently labeled as a “super bug” in antibiotic resistance. Thus, surveillance and investigation on antibiotic resistance mechanisms involved in clinical MRS strains may raise urgent necessity and utmost significance. As a novel antibiotic resistance mechanism, class 1 integron has been identified as a primary source of antimicrobial resistance genes in Gram-negative organisms. However, most available studies on integrons had been limited within Gram-negative microbes, little is known for clinical Gram-positive bacteria. Based on series studies of systematic integrons investigation in hundreds of staphylococci strains during 2001–2006, this review concentrated on the latest development of class 1 integron in MRS isolates, including summary of prevalence and occurrence of class 1 integron, analysis of correlation between integron and antibiotic resistance, further demonstration of the role integrons play as antibiotic determinants, as well as origin and evolution of integron-associated gene cassettes during this study period.     

山东近海鱼类群落分类多样性

根据相关文献整理了山东近海鱼类名录,并根据1998—2009年山东近海鱼类调查名录,应用平均分类差异指数(Δ+)和分类差异变异指数(Λ+)研究了鱼类分类学多样性特征。结果表明,山东近海鱼类名录包括2纲28目91科169属225种,1998年调查仅2纲11目41科58属62种,2006年调查为1纲13目41科71属78种,2009年调查为1纲9目32科55属62种。1998年—2009年调查鱼类种类远远低于鱼类名录记录的种数,分类阶元包含指数较低,平均每属包含1.1种。根据山东近海鱼类名录计算鱼类平均分类差异指数为66.1,分类差异变异指数为141.7;1998—2009年历次调查鱼类平均分类差异指数在60.9—62.7之间,分类差异变异指数在65.4—92.3之间。将1998—2009年历次调查鱼类群落分类多样性指数计算值叠加到山东近海鱼类总名录的95%置信漏斗曲线图,结果表明大部分调查值在置信漏斗曲线之外,目前山东近海鱼类分类多样性已大幅下降。     

京津冀特大城市群生态安全格局时空演变特征及其影响因素

京津冀特大城市群的快速发展显著提升了地区生活水平,但也对生态环境造成了负面影响。以2000—2015年京津冀城市群面板数据为研究样本,建立"压力-状态-响应(PSR)"城市群生态安全协同会诊指标体系,采用TOPSIS和灰色关联组合方法计量其生态安全综合指数(Comprehensive Index of Ecological Security,CIES),运用因子分析法提取关键因素,并通过多元线性回归方法计算上述因素对生态安全的影响程度。结果表明:(1)京津冀城市群生态安全指数已经达到了预警状态,呈现"北高南低,西高东低"的空间格局,亟需建立三地协同联防联控的生态安全防治机制;(2)2000—2015年京津冀城市群的生态安全指数呈小幅波动状态,规划与政策对城市群生态安全指数具有显著影响效应;(3)13地市生态安全指数的演变趋势存在显著的差异,承德、廊坊仍呈下降趋势;(4)城镇化、社会发展以及技术进步对京津冀城市群生态安全具有显著的正相关性,开发水平、经济发展以及生态病理度则呈负相关性。由此,需要划定并严守城市群生态保护红线,控制空间开发强度与速度,以遏制生态恶化;完善并落实京津冀城市群协同发展的规划体系与相应的配套政策支撑体系,以保障城市群生态安全稳定提升;控制经济发展速度,提升社会发展水平,构建城市群一体化社会服务保障体系;提升生态技术研发水平,加大生态空间保护与修复,以降低生态安全风险,保障城市群生态安全格局。     

不同适应条件对细鳞鲑幼鱼游泳能力的影响

为了研究适应条件对鲑科鱼类幼鱼续航游泳能力的影响,在(16.0±0.2)℃和8 mg/L溶解氧条件下,以续航时间作为评定游泳能力的关键指标,通过适应时间、适应流速、加速时间以及测试流速对细鳞鲑幼鱼的续航游泳时间的影响进行了研究,试验采用4因素8水平的均匀设计方案。结果表明,最大适应流速应控制在1—1.5 BL/s为宜,相应的最佳适应时间应为1 h,在合理条件下适应流速和适应时间对续航游泳能力的影响可忽略不计;加速时间只在大流速条件下(0.5 m/s)对续航时间有极显著影响,其他情况的影响可以忽略不计;尽管长时间适应环境更有利于鱼类身体机能的充分调整,但适应时间仍建议控制在1—2 h以内,且受试鱼类要经过试验前的适应能力筛选;测试流速建议控制在3—4 BL/s以内,以避免超过鱼类的最大游泳耐受范围。测试流速对细鳞鲑幼鱼的续航时间有极为显著的影响,其续航时间随测试流速的增加呈幂函数规律衰减。     

Design,synthesis, biological evaluation,and molecular docking of chalcone derivatives as anti-inflammatory agents

In this study, two series of 35 new chalcone derivatives containing aryl-piperazine or aryl-sulfonyl-piperazine fragment were synthesized and their structures were characterized by ¹H, ¹³C and ESI-MS. The in vivo and in vitro anti-inflammatory activities of target compounds were evaluated by using classical para-xylene-induced mice ear-swelling model and ELISA assays. Furthermore, docking studies were performed in COX-2 (4PH9). The in vivo anti-inflammatory assays indicated that most of the target compounds showed significant anti-inflammatory activities. Docking results revealed that the anti-inflammatory activities of compounds correlated with their docking results. Especially, compound 6o exhibited the most potent anti-inflammatory activity in vivo with the lowest docking score of ?17.4 kcal/mol and could significantly inhibit the release of LPS-induced IL-6 and TNF-α in a dose-dependent manner in vitro.     

Cytosolic thioredoxin reductase 1 is required for correct disulfide formation in the ER

Folding of proteins entering the secretory pathway in mammalian cells frequently requires the insertion of disulfide bonds. Disulfide insertion can result in covalent linkages found in the native structure as well as those that are not, so‐called non‐native disulfides. The pathways for disulfide formation are well characterized, but our understanding of how non‐native disulfides are reduced so that the correct or native disulfides can form is poor. Here, we use a novel assay to demonstrate that the reduction in non‐native disulfides requires NADPH as the ultimate electron donor, and a robust cytosolic thioredoxin system, driven by thioredoxin reductase 1 (TrxR1 or TXNRD1). Inhibition of this reductive pathway prevents the correct folding and secretion of proteins that are known to form non‐native disulfides during their folding. Hence, we have shown for the first time that mammalian cells have a pathway for transferring reducing equivalents from the cytosol to the ER, which is required to ensure correct disulfide formation in proteins entering the secretory pathway.     

环京津山水林田湖草多目标跨区联动保护修复模式

河北环京津山水林田湖草生态保护修复试点是国家第一批山水林田湖草生态保护修复试点之一。环京津试点区域位居京畿要地,是京津冀城市群的生态安全屏障。该区域生态系统服务退化,山水林田湖草要素资源约束趋紧,生态修复难度大任务重,联防联控与协同共建机制有待健全。为此,试点实施方案明确了“自然分区-突出问题-绿色奥运”三维导向的修复思路,制定了“指标引导-空间定位-任务聚焦-工程落地”四步推进的实施路径。试点实施2年多来,河北省协同京津全面开展山水林田湖草生态系统保护修复工作,区域生态环境协同治理取得了阶段性成果,形成了以本底层、管理层、政策层、目标层为基本构架,以多要素综合、多部门协作、多渠道保障、多目标优化为核心内容的山水林田湖草“多目标跨区联动”保护修复模式。     

Development and application of a loop-mediated isothermal amplification method on rapid detection of Pseudomonas aeruginosa strains

We developed and evaluated the specificity and sensitivity of a simple loop-mediated isothermal amplification (LAMP) method for rapid detection of P. aeruginosa strains. The optimal reaction condition was found to be 65°C for 45 min, with the detection limit as 100 fg DNA/tube and 10 CFU/reaction. Application of LAMP assays were performed 426 clinical samples (including 252 P. aeruginosa and 174 non- P. aeruginosa isolates) using a rapid procedure and easy result confirmation. Sensitivity of LAMP and PCR assays was found to be 97.6% (246/252) and 90.5% (228/252), respectively; with a 100% specificity for both assays.     

Validation of Respiratory Inductance Plethysmography for Measuring Tidal Volume in Swine

Measuring tidal volume (V_T) in nonintubated swine or swine with leaking breathing circuits is challenging. The aim of this study was to validate respiratory inductance plethysmography (RIP) for measuring V_T in swine that are comparable in size to adult humans. To determine calibration curves, V_T and RIP readings were obtained from anesthetized swine (n = 8; weight, 46–50 kg) during positive-pressure (mechanical) ventilation and spontaneous breathing. For positive-pressure ventilation, 6 pigs were mechanically ventilated by using the pressure-control mode. The 2 pigs in the spontaneously breathing cohort each received a single intravenous bolus dose of propofol to abolish spontaneous breathing; V_T was measured during gradual return of their respiratory drive. A flow–volume sensor was placed between the proximal end of the endotracheal tube and breathing circuit for the recording of inspiratory and expiratory V_T. RIP readings were recorded by using 2 bands, which simultaneously measured ribcage and abdominal excursions. The data revealed that V_T was linearly correlated with the movements of both ribcage and abdomen as measured by using plethysmography over a large range of tidal volume (44 to 1065 mL). In addition, the intercept of the linear equation was small or even negative during spontaneous breathing but increased significantly (maximum, 145 mL, 59.2 ± 35.1 mL) during positive pressure ventilation. Our results indicate that V_T in swine can be calculated by using a simple univariate linear regression equation with RIP readings obtained during either mechanical ventilation or spontaneous breathing.Abbreviations: RIP, respiratory inductance plethysmography; V_T, tidal volumeIn animal care and research, the respiratory function of swine is widely assessed by measuring tidal volume (V_T).⁶ Although V_T is easy to measure in intubated pigs, it is difficult to measure in swine that are either nonintubated or have significant breathing circuit leakage^16,24. Using facemasks attached to minimally restrained swine is currently the method of choice for measuring V_T. This methodology has multiple limitations, including incomplete sealing between the pig''s face and the mask, which is difficult to adapt to these animals. A reliable, minimally invasive method for determining V_T in this species is needed.Respiratory inductance plethysmography (RIP)^11,15 is a viable alternative to measuring V_T. Using RIP, both ribcage and abdominal movements can be recorded. The amplitude changes of the ribcage and abdomen are linearly correlated to the size of the corresponding V_T in humans. This method has been validated in humans^1,13 and is widely used clinically in adults,^14,18 newborns and infants.^5,8 RIP has also been used on animals including sheep⁴ and dogs.¹⁷However, RIP has not yet been validated for use in swine that are comparable in size to adult humans. Considering the profound physiologic and anatomic differences in the respiratory system between swine and humans,^12,20 the validation of plethysmography for use in humans might not extrapolate readily to swine, which are one of the most commonly used animal models in biomedical research. Here we sought to validate the RIP method for calculating V_T in swine during both positive-pressure ventilation and spontaneous breathing.