Comprehensive prenatal diagnostics: Exome versus genome sequencing

Objective

This study aimed to assess the diagnostic yield of prenatal genetic testing using trio whole exome sequencing (WES) and trio whole genome sequencing (WGS) in pregnancies with fetal anomalies by comparing the results with conventional chromosomal microarray (CMA) analysis.

Methods

A total of 40 pregnancies with fetal anomalies or increased nuchal translucency (NT ≥ 5 mm) were included between the 12th and 21st week of gestation. Trio WES/WGS and CMA were performed in all cases.

Results

The trio WES/WGS analysis increased the diagnostic yield by 25% in cases with negative CMA results. Furthermore, all six chromosomal aberrations identified by CMA were independently detected by WES/WGS analysis. In total, 16 out of 40 cases obtained a genetic sequence variant, copy number variant, or aneuploidy explaining the phenotype, resulting in an overall WES/WGS diagnostic yield of 40%. WES analysis provided a more reliable identification of mosaic sequence variants than WGS because of its higher sequencing depth.

Conclusions

Prenatal WES/WGS proved to be powerful diagnostic tools for fetal anomalies, surpassing the diagnostic yield of CMA. They have the potential to serve as standalone methods for prenatal diagnosis. The study highlighted the limitations of WGS in accurately detecting mosaic variants, which is particularly relevant when analyzing chorionic villus samples.     

高钙废水颗粒污泥中古菌菌群结构变化的分析

为了解高浓度Ca~(2+)与颗粒污泥中古菌菌群结构的关系,利用高通量测序分析IC(Internal Circulation)反应器(以废纸造纸废水为处理对象)内不同高度处颗粒污泥中古菌菌群组成,并利用SEM(Scanning Electron Microscope)和EDS(Energy Dispersive X-ray Spectroscopy)分析颗粒污泥的形态结构和元素组成,同时借助红外光谱和XRD(X-ray diffraction)分析不同高度处颗粒污泥化学结构中各官能团的分布情况和无机成分.结果表明,随着反应器高度的增加,颗粒污泥中的无机成分CaCO_3也随着增加,而种泥中钙含量只有1.81%.种泥和ICR反应器内的颗粒污泥中古菌在门分类水平上主要包括Euryarchaeota和Bathyarchaeota,两者之和占90%以上.在属分类水平上,主要包括Methanosaeta、Methanoregula、Methanobacterium、Methanosarcina、Methanolinea、Methanospirillum等.种泥中古菌的物种多样性要明显高于IC反应器中,在IC反应器中不同高度处古菌生物多样性由高到低的顺序是5 m2 m7 m,5 m处的古菌物种更加丰富.随着反应器高度的增加,乙酸营养型甲烷菌的相对丰度呈现递增趋势,氢营养型甲烷菌则呈现递减趋势,而种泥中氢营养型甲烷菌相对丰度较大.这表明颗粒污泥在高钙废水的长期作用下,氢营养型甲烷菌的相对丰度减少,乙酸营养型甲烷菌的相对丰度增多,系统中古菌物种的相对丰度和多样性有所下降.CaCO_3沉淀使颗粒污泥的产甲烷活性降低,主要表现为其对氢营养型甲烷菌具有较大的抑制作用.     

BiVO4表面氧缺陷调控及其光催化氧化三价砷

以乙二醇为溶剂,采用溶剂热-煅烧法制备缺陷型BiVO₄光催化剂,通过控制溶剂热反应时间调控BiVO₄表面氧缺陷以增强对As （III）的光催化氧化性能.同时,借助各种表征手段如XRD、SEM和XPS等分析样品的晶型结构、形貌特征及化学组成等性质,考察其在可见光下对As（III）的光催化氧化性能,并研究其氧化机理.结果表明,溶剂热反应时间对BiVO₄的晶粒尺寸和光吸收性能没有影响,但能通过影响比表面积调控BiVO₄的表面氧缺陷浓度.经优化得到,反应时间为14 h时制备的BiVO₄光催化剂（BiVO-14）对As（III）（6 mg·L^-1）的氧化效率高达95.7%,并具有良好的光催化稳定性.BiVO₄氧化As （III）的主要途径是光生空穴（h⁺）的直接氧化作用.表面氧缺陷能增强导电性能,促进电荷分离和迁移,强化h⁺的氧化作用,从而提高BiVO₄的光催化氧化性能.BiVO-14能有效促使As（III）转化为低毒的As（V）,在饮用水源As污染去除方面具有广阔应用前景.     

浙江省气溶胶垂直分布及区域传输分析

利用6个激光雷达站点数据从年际和季节变化尺度对浙江省2017~2018年气溶胶垂直分布特征进行研究,并结合污染物浓度数据分析了浙江省主要颗粒物类型的季节差异.结果表明,大部分站点2018年气溶胶消光系数整体小于2017年;边界层内消光系数空间上呈中部高东西低的分布形态;消光系数季节变化表现为冬季最高,秋季其次,而春夏较低;气溶胶在春、夏季集中在地面上方1~2km以内,冬季主要分布在1km以下,秋季受高空气溶胶影响,6个站点呈现出不同的垂直分布模式.进一步,选取发生在2018年4月和7月两次气溶胶跨区域传输过程,综合CALIPSO和MODIS卫星数据、以及后向轨迹、PSCF与CWT模式对污染物来源与传输机制进行探索,发现来自AOD高值区的气团显著加重本地污染.     

Source apportionment of VOCs in a typical medium-sized city in North China Plain and implications on control policy

Characteristics of atmospheric VOCs (volatile organic compounds) have been extensively studied in megacities in China, however, they are scarcely investigated in medium/small-sized cities in North China Plain (NCP). A comprehensive research on possible sources of VOCs was conducted in a medium-sized city of NCP, from May to September 2019. A total of 143 canister samples of 8 sites in Xuchang city were collected, and 57 VOC species were detected. The average VOC concentrations were 42.6 ± 31.6 μg/m³, with 53.7 ± 31.0 μg/m³ and 32.1 ± 27. 8 μg/m³, in the morning and afternoon, respectively. Alkenes and aromatics contributed 80% of the total ozone formation potential (OFP). Aromatics accounted for more than 95% of secondary organic aerosol potential (SOAP). VOCs were dominated by the local emission with significant transport from the southeast direction. PMF analysis extracted 6 sources, which were combustion (33.1%), LPG usage (19.3%), vehicular exhaust & fuel evaporation (15.8%), solvent usage (15.2%), industrial (9.11%) and biogenic (7.51%), respectively and they contributed 33.4%, 17.6%, 12.9%, 18.6%, 9.28% and 8.22% to the OFP, respectively. Combustion and LPG usage were the dominant VOC sources; and combustion, solvent usage and LPG usage were the main sources of OFP in Xuchang city, which were different to megacities in China with a high contribution from vehicular exhaust, solvent usage and industry, suggesting specific control strategies on VOCs need to be implemented in medium-sized city such as Xuchang city.     

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.     

淮南煤田石炭-二叠系煤中有害元素分布与富集赋存特征

为调查分析淮南煤田石炭—二叠系有害元素的分布与富集赋存特征,采用ICP-MS对张集矿、潘三矿和顾桥矿共159件样品的煤中微量元素含量进行了测试分析,分析了11种有害元素的含量分布特征、富集特征,利用聚类图谱探讨了有害元素的富集赋存特征。研究结果表明:除As外,绝大多数元素的平均含量均低于地壳丰度,除Ba和As外,绝大多数元素的平均含量均高于中国煤、美国煤和世界;采用地壳丰度作为对比值所得到的富集系数严重偏离了煤中有害元素的分布特征,与中国煤、美国煤和世界煤相对比较,Cd高度富集,Cr、Cu、Ni、Pb、Sn、Ti为轻度富集至富集;不同煤层有害元素的富集程度存在较大的差异,Cd、Cr、Pb、Ni、Sn易出现富集,Cd为典型富集的有害元素,在8煤、7煤、6煤、5煤和4中出现高度富集;不同矿井主采煤层中有害元素富集程度存在差异,明显高度富集的有害元素为Cd、Ti;原煤灰分中的酸性组分超过灰成分的80%,灰成分指数平均碱酸比为9. 64%,煤中有害元素主要为陆源碎屑来源,部分存在自生矿物; As、Ni赋存富集于黄铁矿中,Ba、Mn可能赋存富集于碳酸盐矿物中,Cr可能吸附富集于粘土矿物中、Pb、Sn、Ti可能与硫酸盐矿物有关,Zn、Cu可能赋存在闪锌矿中,Cd可能赋存富集于黄铁矿和吸附富集于粘土矿物中,其富集程度与沉积环境和煤层稳定程度有关。     

CANON工艺短程硝化恢复调控及微生物种群结构变化

以短程硝化恶化的全程自养脱氮工艺（CANON）污泥为研究对象,在间歇曝气序批式反应器（SBR）中开展自养脱氮运行效果的恢复调控研究,并基于微生物群落结构变化探究微生物调控机理.结果表明,高氨氮（NH₄⁺-N ≥300mg/L）和调节曝停比至1：3,可有效抑制亚硝酸盐氧化菌（NOB）.稳定后期,亚硝酸盐氧化率（NOR）逐渐降至2.30g N/（m³·h）,ΔNO₃^--N/ΔNH₄⁺-N逐渐降至0.13,总氮去除率（TNRR）提高到0.35kg N/（m³·d）,后延长厌氧段时间至90min,可使NOR进一步下降接近0.16S rDNA高通量测序结果表明,从恢复阶段初到稳定阶段,检测到NOB主要菌属为Nitrospira,其相对丰度从3.96%降至0.64%,Candidatus_Jettenia菌属（属于厌氧氨氧化菌（AnAOB））相对丰度从46.68%上升至49.98%.可见,通过短期提高进水氨氮浓度可使NOB得到有效抑制,并逐渐被淘汰,使AnAOB得到富集,AOB相对丰度稳态,CANON系统得到恢复.     

华北南部冬季大气亚微米颗粒物数浓度变化

2018年1月华北平原经历了一段持续时间久、影响范围广和颗粒物浓度高的重污染时期.本研究通过SMPS+E扫描电迁移率粒径谱仪,选取华北平原南部某郊区点位,对此次重污染期间颗粒物数浓度粒径分布演化进行连续观测研究.结果表明,观测期间环境空气质量尤其是PM_2.5平均浓度为141.32 μg/m³.大气亚微米颗粒物数浓度主要集中在核模态和爱根核模态的超细粒径段（78.9%）,呈递减型单峰分布,颗粒物平均数浓度为83174cm^-3.重污染天时,核模态颗粒物数浓度明显增高,对应低风速（1.5±0.4）m/s、高相对湿度（90.8±4.5）%和低O₃浓度（15.8±8.3）μg/m³.48h后向轨迹显示,观测点位气溶胶主要受湖北省、陕西省和山西省临近省份的传输影响.潜在源贡献因子法和浓度权重轨迹表明,气溶胶潜在源区主要为本地源和观测点位以北的区域.     

北京城区不同组分PM2.5散射特性及来源分析

近年来北京城区PM_2.5浓度下降伴随其中二次离子占比升高,为探索不同组分PM_2.5散射特性及其来源,于2020年12月至2021年11月开展了小时分辨率的PM_2.5及其组分浓度和散射系数的连续在线监测,分析了PM_2.5组分及散射的特征和来源.结果表明,研究期间北京城区PM_2.5最主要组分为NO^-₃,PM_2.5中ω(NO^-₃)和ω(SNA)分别为24%和46%.根据浓度和组分占比将PM_2.5划分为6种类型：优型出现频率最高,为56%,四季分布均匀,PM_2.5中ω(SNA)、ω(OM)和ω(FS)相当,分别为32%、 32%和28%;沙尘(D)型和OM(O)型全年出现频率较低,分别以FS和OM为主要组分,PM_2.5中ω(FS)和ω(OM)分别为66%和46%,主要分布于春季和夏季;OM+SO₄