Horizontal and vertical gene transfer drive sediment antibiotic resistome in an urban lagoon system

Rapid urbanization has resulted in pervasive occurrence of antibiotic resistance genes (ARGs) in urban aquatic ecosystems. However, limited information is available concerning the ARG profiles and the forces responsible for their assembly in urban landscape lagoon systems. Here, we employed high-throughput quantitative PCR (HT-qPCR) to characterize the spatial variations of ARGs in surface and core sediments of Yundang Lagoon, China. The results indicated that the average richness and absolute abundance of ARGs were 11 and 53 times higher in the lagoon sediments as compared to pristine reference Tibetan lake sediments, highlighting the role of anthropogenic activities in ARG pollution. Co-occurrence network analysis indicated that various anaerobic prokaryotic genera belonging to Alpha-, Deltaproteobacteria, Bacteroidetes, Euryarchaeota, Firmicutes and Synergistetes were the potential hosts of ARGs. The partial least squares-path modeling (PLS-PM) analysis revealed positive and negative indirect effects of physicochemical factors and heavy metals on the lagoon ARG profiles, via biotic factors, respectively. The horizontal (mediated by mobile genetic elements) and vertical (mediated by prokaryotic communities) gene transfer may directly contribute the most to drive the abundance and composition of ARGs, respectively. Furthermore, the neutral community model demonstrated that the assembly of sediment ARG communities was jointly governed by deterministic and stochastic processes. Overall, this study provides novel insights into the diversity and distribution of ARGs in the benthic habitat of urban lagoon systems and underlying mechanisms for the spread and proliferation of ARGs.     

Protonated acetone ion chemical ionization time-of-flight mass spectrometry for real-time measurement of atmospheric ammonia

Ammonia (NH₃) is ubiquitous in the atmosphere, it can affect the formation of secondary aerosols and particulate matter, and cause soil eutrophication through sedimentation. Currently, the use of radioactive primary reagent ion source and the humidity interference on the sensitivity and stability are the two major issues faced by chemical ionization mass spectrometer (CIMS) in the analysis of atmospheric ammonia. In this work, a vacuum ultraviolet (VUV) Kr lamp was used to replace the radioactive source, and acetone was ionized under atmospheric pressure to obtain protonated acetone reagent ions to ionize ammonia. The ionization source is designed as a separated three-zone structure, and even 90 vol.% high-humidity samples can still be directly analyzed with a sensitivity of sub-ppbv. A signal normalization processing method was designed, and with this new method, the quantitative relative standard deviation (RSD) of the instrument was decreased from 17.5% to 9.1%, and the coefficient of determination was increased from 0.8340 to 0.9856. The humidity correction parameters of the instrument were calculated from different humidity, and the ammonia concentrations obtained under different humidity were converted to its concentration under zero humidity condition with these correction parameters. The analytical time for a single sample is only 60 sec, and the limit of detection (LOD) was 8.59 pptv (signal-to-noise ratio S/N = 3). The ambient measurement made in Qingdao, China, in January 2021 with this newly designed CIMS, showed that the concentration of ammonia ranged from 1 to 130 ppbv.     

混凝-接触氧化处理印染废水的试验研究

对混凝-生物接触氧化法处理印染废水进行研究。混凝部分试验研究了聚合氯化铝(PAC)、聚合硫酸铁(PFS)、氯化铁(FC)3种混凝剂对印染废水的处理效果。结果表明:PAC的处理效果最好,并确定了混凝的最佳pH值和投加量。在生物接触氧化试验部分,主要考察了水力停留时间和曝气量对COD去除率的影响,确定了最佳工艺参数。经试验,脱色率和COD去除率分别达95.68%和95.23%。     

湿法脱硫入口SO_2浓度对脱硫效率影响的非线性回归分析

通过对太原二电厂11号FGD现场168运行数据采用一元非线性回归分析和基于距离判别法的多元非线性回归分析两种不同的分析方法,利用最小二乘曲线拟合法建立了不同出口SO2浓度范围内的入口SO2浓度与脱硫效率的非线性回归方程,为实际运行过程中脱硫效率的预测和分析提供理论依据。此外,分析了入口SO2浓度对脱硫效率的影响,为运行人员在实际运行过程中提高脱硫效率而提供控制思路。     

Cleaning symbiosis in an obligate goby–shrimp association

Shrimps from the genus Alpheidae had never been considered as a cleaner organism. In the present study, we demonstrate for the first time, Alpheus rapax engaging in cleaning symbiosis with its gobiid fish associate Myersina macrostoma. Within 450 min of observation time, 9 instances totalling 546 s of cleaning behaviour were recorded. Cleaning behaviour was always preceded by physical contact between the shrimps and their goby associates. The shrimps initiated all cleaning incidents, but these were always terminated by the gobies. Cleaning sessions were observed to occur mostly in the tail region (60.8 %) and followed by the head region (26.2 %). In one instance, a shrimp was observed to clean the gills of its goby associate. The gobies appear to exert some control as to where they were being cleaned by repositioning themselves during a cleaning session.     

A study on vertical greening practice emphasizing ecological benefits in Xiamen City of China

Through the practice of vertical greening, which is an important method for modern city greening, a city’s natural geographic conditions and rich plant resources can be efficiently utilized. Using vertical greening to shape the characteristics of a city is a promising method for sustainable development. Integration of vertical greening with urban characteristics offers huge ecological and cultural benefits. Vertical greening was adopted in China much later than other developed cities in the world and is still in the exploratory stage in most of the cities. As one of the pioneer cities to carry out vertical greening in China, Xiamen has managed to project it as one of the city highlights. In this study, we analyzed the problems that Xiamen City faced during its development and the important role vertical greening has played in the urban landscape. In addition, humanistic and ecological benefits of vertical greening are illustrated through an experimental study.     

环境激素的内分泌干扰机制及其对人体的影响

环境激素问题的调查研究标志着地球环境时代的到来。重点讨论了环境激素的分类、特征及其内分泌干扰机制,并涉及了环境激素对人体的影响,以期引起人们的关注和重视,加强这方面的调查研究。     

Turbulence suppression by suspended sediment within a geophysical flow

Experiments are performed in a mixing box to evaluate the effect of suspended sediment on turbulence generated by an oscillating grid. Quartz-density sand of varying sizes and concentrations is used, and particle image velocimetry is employed to quantify only the fluid phase. Results show that (1) while a relatively large secondary flow field is present in the box, turbulence is a maximum near the grid and it decreases systematically toward the water surface; (2) relatively high concentrations of fine sediment can markedly alter this secondary flow field and significantly decrease both the time-mean and turbulent kinetic energy within the flow, yet these same sediment concentrations have little effect on the integral time and length scales derived for each velocity component; and (3) the overall turbulence suppression observed can be related to the transfer of energy from the fluid to the sediment and the maintenance of a suspended sediment load rather than commonly employed turbulence modulation criteria. These experimental data demonstrate unequivocally that the presence of a suspended sediment load can significantly reduce overall turbulent kinetic energy, and these results should be applicable to a range of sediment-laden geophysical flows.     

Partitioning of \alpha and \beta diversity using hierarchical Bayesian modeling of species distribution and abundance

Diversity partitioning is becoming widely used to decompose the total number of species recorded in an area or region \((\gamma )\) into the average number of species within samples \((\alpha )\) and the average difference in species composition \((\beta )\) among samples. Single-value metrics of \(\alpha \) and \(\beta \) diversity are popular because they may be applied at multiple scales and because of their ease in computation and interpretation. Studies thus far, however, have emphasized observed diversity components or comparisons to randomized, null distributions. In addition, prediction of \(\alpha \) and \(\beta \) components using environmental or spatial variables has been limited to more extensive data sets because multiple samples are required to estimate single \(\alpha \) and \(\beta \) components. Lastly, observed diversity components do not incorporate variation in detection probabilities among species or samples. In this study, we used hierarchical Bayesian models of species abundances to provide predictions of \(\alpha \) and \(\beta \) components in species richness and composition using environmental and spatial variables. We illustrate our approach using butterfly data collected from 26 grassland remnants to predict spatially nested patterns of \(\alpha \) and \(\beta \) based on the predicted counts of butterflies. Diversity partitioning using a Bayesian hierarchical model incorporated variation in detection probabilities by butterfly species and habitat patches, and provided prediction intervals for \(\alpha \) and \(\beta \) components using environmental and spatial variables.     

大气细颗粒物暴露后小鼠肺组织microRNA差异表达谱芯片分析

microRNAs作为临床疾病早期诊断的新型生物标记物越来越受到重视,为了进一步探究其在大气污染暴露后引起疾病的分子染毒机制。本研究通过建立大气污染小鼠染毒模型,利用Agilent芯片筛查小鼠肺组织中microRNAs差异表达谱,并通过实时荧光定量PCR方法验证芯片结果,使用Target Scan,PITA,microRNAorg数据对差异mi RNA进行靶基因预测,进行靶基因富集的基因功能(GO)和信号通路(KEGG)分析。结果显示,大气细颗粒物暴露2周后小鼠肺组织microRNAs有显著差异表达谱,高剂量暴露组与对照组比较有4个mi RNAs上调,低剂量暴露组与对照组比较有2个mi RNAs上调,高剂量组与低剂量组比较,有4个mi RNAs上调(标准为fold change值=2.0且P值=0.05),挑选差异明显的mi RNAs进行q RT-PCR验证,mi R-139-5p、mi R-691及mi R-340-3p变化趋势与芯片一致,生物信息学结果显示,差异表达的mi RNAs所调控的靶基因明显富集于34个GO通路(包括RNA转录酶II启动子的转录,RNA拼接,DNA模板,蛋白质结合和核酸结合)和32个KEGG通路(主要集中轴突导向通路和癌症通路)。综上所述,大气细颗粒物暴露染毒可诱导小鼠肺组织中mi R-139-5p、mi R-691及mi R-340-3p明显上调,且生物信息学分析提示中枢神经系统发育及癌症通路可能作为PM2.5暴露相关差异表达mi RNAs调控靶基因介导的主要致病通路。