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In situ biomass burning enhanced the contribution of biogenic sources to sulfate aerosol in subtropical cities
No full textSulfurous gases released by biogenic sources play a key role in the global sulfur cycle. However, the contribution of biogenic sources to sulfate aerosol in the urban atmosphere has received little attention. Emission sources and formation process of sulfate in Guangzhou, a subtropical mega-city in China, were clarified using multiple methods, including isotope tracers and chemical markers. The delta 18O of sulfate suggested that secondary sulfate was the dominant component (84 %) of sulfate aerosol, which mainly formed by transition metal ion (TMI) catalyzed oxidation (31 %) and OH radical oxidation (30 %). The factors driving secondary sulfate formation were revealed using a tree boosting model, which suggested that NH3, temperature, and oxidants were the most important factors. The delta 34S of sulfate indicated that biogenic sources accounted for annual average of 26.0 % of the sulfate, which increased to 30.4 % in winter monsoon period. Rice straw burning enhanced sulfate formation by promoting the release of reduced sulfur from soil, which is rapidly converted into sulfate under a subtropical urban atmosphere with high concentration of NH3 and oxidants. This study revealed the important influence of rice straw burning on biogenic sulfur emission during the rice harvest, thereby providing insight into the sulfur cycle and regional air pollution
Sulfides in waters could be converted to pyrites through mineralization with Fe/MgO/Ni(II) promotion
No full textCurrent sulfide removal techniques are generally associated with secondary pollution. In this work, Fe/MgO/Ni (II) system was constructed to remove sulfide from waters thoroughly by transforming it into stable pyrite (FeS2). The transformation could be finished quickly through the promotion of Ni2+ at all pH conditions, and the optimal Ni/Fe molar ratio was 1.0. The FeS2 could be formed in 360 min and the reaction was finished at 600 min when the initial concentration of sulfide and Ni2+ was 181.95 mg/L and 164.52 mg/L, respectively. The highest content of SO42- was merely 2.06 %, while the content of S2O32- /SO32- increased with reaction (56.99 %-67.21 %) in the whole process. The content of sulfide and Ni2+ in the solution were not detected after reaction. The mineralization process was not affected by sodium salt addition, however, it was greatly affected by calcium salt, where the ascensional range of S2O32-/SO32- and SO42- was 50.03 %-70.06 % and 9.84 %-14.76 %, respectively, and the content of sulfide on Fe/MgO was only 14.66 %. Higher temperature would produce more SO42- and H+. The rapid formation mechanism of FeS2 was mainly through Ni2+ substituting Fe in FeS to form Ni-doped FeS precursors that reacted with polysulfide and then promoted the nucleation of FeS2, in the meantime, the reaction to form S2O32-/SO32-, SO42-, Ni(OH)2 and H+ also were generated in this process. This study provides a new insight for the efficient treatment of sulfide containing wastewater
Surface water-groundwater interactions drive the spatial variability of dissolved heavy metals and interfacial fluxes in mangrove intertidal zones
No full textThe intertidal aquifer is a crucial area that significantly influences the transport of heavy metals and the health of coastal environment. In this study, we used a 3-dimensional sampling method to analyze the spatial variability of heavy metals in the groundwater of the mangrove intertidal zone in China. The pollution level of heavy metals and their release processes into coastal waters through groundwater discharge were also explored. Our findings revealed high spatial heterogeneity of heavy metals occurred along the cross-shore, parallel-shore, and depth directions. Specifically, heavy metals exhibited inconsistent variation trends between the seawater infiltrated zone and groundwater discharge zone along the cross-shore direction. Fe, Cr, Cu, Zn, and Pb exhibited a similar variation trend along the cross-shore direction, but were opposite to that of Hg and As. In addition, most heavy metals showed higher concentrations in mangrove groundwater compared to inland pond water and coastal seawater, indicating that mangrove intertidal zone played a crucial role in sequestering heavy metals. The spatial variability of heavy metals can be attributed to different exchange types and magnitudes between the surface water and groundwater, as well as the complex biogeochemical reactions. Our study also identified a slight pollution level of Zn and Hg, and high groundwater discharge-derived fluxes of Hg and As compared with other study sites in the world. In addition, this study highlights the importance of considering different groundwater end-member, especially for redox sensitive heavy metals, when determining groundwater discharge-derived fluxes into the surface water in mangrove intertidal zone
SERS-based microdevices for use as <i>in vitro</i> diagnostic biosensors
No full textAdvances in surface-enhanced Raman scattering (SERS) detection have helped to overcome the limitations of traditional in vitro diagnostic methods, such as fluorescence and chemiluminescence, owing to its high sensitivity and multiplex detection capability. However, for the implementation of SERS detection technology in disease diagnosis, a SERS-based assay platform capable of analyzing clinical samples is essential. Moreover, infectious diseases like COVID-19 require the development of point-of-care (POC) diagnostic technologies that can rapidly and accurately determine infection status. As an effective assay platform, SERS-based bioassays utilize SERS nanotags labeled with protein or DNA receptors on Au or Ag nanoparticles, serving as highly sensitive optical probes. Additionally, a microdevice is necessary as an interface between the target biomolecules and SERS nanotags. This review aims to introduce various microdevices developed for SERS detection, available for POC diagnostics, including LFA strips, microfluidic chips, and microarray chips. Furthermore, the article presents research findings reported in the last 20 years for the SERS-based bioassay of various diseases, such as cancer, cardiovascular diseases, and infectious diseases. Finally, the prospects of SERS bioassays are discussed concerning the integration of SERS-based microdevices and portable Raman readers into POC systems, along with the utilization of artificial intelligence technology
Physiological and transcriptomic responses of Aurelia coerulea polyps to acidified seawater conditions
No full textScyphozoan jellyfish, known for their evolutionary position and ecological significance, are thought to exhibit relatively notable resilience to ocean acidification. However, knowledge regarding the molecular mechanisms underlying the scyphozoan jellyfish response to acidified seawater conditions is currently lacking. In this study, two independent experiments were conducted to determine the physiological and molecular responses of moon jellyfish (Aurelia coerulea) polyps to within- and trans-generational exposure to two reduced pH treatments (pH 7.8 and pH 7.6). The results revealed that the asexual reproduction of A. coerulea polyps significantly declined under acute exposure to pH 7.6 compared with that of polyps at ambient pH conditions. Transcriptomics revealed a notable upregulation of genes involved in immunity and cytoskeleton components. In contrast, genes associated with metabolism were downregulated in response to reduced pH treatments after 6 weeks of withingenerational acidified conditions. However, reduced pH treatments had no significant influence on the asexual reproduction of A. coerulea polyps after exposure to acidified conditions over a total of five generations, suggesting that A. coerulea polyps may acclimate to low pH levels. Transcriptomics revealed distinct gene expression profiles between within- and trans-generational exposure groups to two reduced pH treatments. The offspring polyps of A. coerulea subjected to trans-generational acidified conditions exhibited both upregulated and downregulated expression of genes associated with metabolism. These physiological and transcriptomic characteristics of A. coerulea polyps in response to elevated CO2 levels suggest that polyps produced asexually under acidified conditions may be resilient to such conditions in the future
IIS/FoxO通路在Argopecten属扇贝寿命决定中的作用机制
No full text抗衰老机制一直是生命科学前沿热点问题。在处于不同进化地位的陆生模式生物研究中发现遗传因素和环境因素是寿命的决定性因素。胰岛素/胰岛素样生长因子1信号（Insulin/IGF-1signaling pathway, IIS）通路是进化上最保守的衰老途径，该通路中核心成员基因功能的完全或部分丧失的突变会有效延长生物体寿命。然而，通过遗传突变或诱变等方式延长寿命的同时，通常会以损害机体其它健康性能为代价。因此，非常有必要研究由进化中的基因突变自然延长寿命且保持健康的调控机制，为探究动物寿命决定机制提供新途径。海湾扇贝和紫扇贝由共同祖先分化而来，二者在长期适应不同环境的进化过程中，各自基因组的遗传突变导致了二者不同的寿命周期，海湾扇贝寿命小于14个月，而紫扇贝寿命长达7-10年，因此两种扇贝是研究自然条件下寿命决定机制的理想模型。然而，目前鲜有关于海洋无脊椎动物寿命决定机制的研究报道。因此，本研究以海湾扇贝和紫扇贝为实验对象，对IIS/FoxO通路4个核心基因（IGF2、IGF1R、FoxO、PTEN）的结构、表达与蛋白活性进行系统研究，明确IIS/FoxO通路核心基因在营养感应、基因组稳定以及寿命决定中的作用机制。主要研究结果和结论如下：
一、系统表征了海湾扇贝和紫扇贝IIS/FoxO通路核心基因IGF2、IGF1R、PETN和FoxO的基因结构和时空组织表达模式，明确了核心基因在两种扇贝间存在较大的遗传变异。通过基因克隆发现，海湾扇贝和紫扇贝中IIS/FoxO通路核心基因均为单拷贝。序列同源比对发现，与紫扇贝ApIGF2相比，海湾扇贝AiIGF2中存在大量胞嘧啶（C）到胸腺嘧啶（T）的转换突变，这种突变会改变潜在密码子，增加其编码基础氨基酸的疏水性，造成功能改变的多肽累积，从而导致海湾扇贝为短寿命表型。AiIGF1R和ApIGF1R胞外配体结合域中存在21个SNPs和1个特异性糖基化位点。AiFoxO和ApFoxO蛋白在第21位Akt磷酸化位点附近存在的2个氨基酸变异，推测该变异可能会影响Akt对FoxO蛋白磷酸化的程度。其中，AiFoxO蛋白第76位Thr特异性磷酸化位点恰巧位于DNA结合结构域内，可能对FoxO转录活性产生影响。AiPTEN和ApPTEN蛋白在核心区域“HCxxGxxR”的邻近位点发生了氨基酸变异，这可能会导致PTEN磷酸酶活性的不同。此外，海湾扇贝和紫扇贝外套膜和性腺中的IGF2和IGF1R表达量随龄期增加呈现上升趋势，而FoxO和PTEN表达量随龄期增加而减少，暗示外套膜和性腺是扇贝衰老的代表性组织。
二、分析海湾扇贝和紫扇贝中IGF2、IGF1R、PETN和FoxO的不同遗传变异对蛋白活性的影响。伴随着机体生长发育，IGF1R与IGF2互作强度逐渐升高；短寿命海湾扇贝中IGF1R与配体IGF2的互作强度高于长寿命紫扇贝。海湾扇贝和紫扇贝中IGF1R激酶活性和磷酸化水平随龄期呈现先升高后下降的趋势，但衰老期的IGF1R激酶活性和和磷酸化程度仍高于稚贝期，表明IGF1R激酶积极响应扇贝发育与衰老过程中所产生的信号，以调控扇贝生长发育与存活。而紫扇贝中PTEN磷酸酶活性始终高于海湾扇贝，且衰老期扇贝中PTEN磷酸酶活性很低，表明PTEN的失活会介导细胞衰老。在海湾扇贝中，FoxO的Akt磷酸化水平随着龄期增加而升高，且与紫扇贝相比，其FoxO具有更高的磷酸化水平，表明扇贝需要低磷酸化水平的FoxO来激活下游长寿相关靶基因的表达，以延长机体寿命。
三、结合体内体外实验，明确了海湾扇贝和紫扇贝中IIS/FoxO通路参与营养感应和电离辐射下适应性调控的作用机制。饮食限制后，两种扇贝中IIS/FoxO通路核心基因表达量变化趋势一致，通路上游信号传感器IGF2与IGF1R表达水平显著下调，而通路下游效应器FoxO和PTEN表达水平显著上调，但海湾扇贝对营养限制的响应更快、幅度更大。饮食限制导致压力应答因子FoxO蛋白的磷酸化水平下降，核定位增加，其下游抗氧化应激和自噬相关靶基因ULK2、ATG8、SOD、CAT和GADD45均被激活，细胞老化指标β-Gal活性显著下降，暗示海湾扇贝和紫扇贝中IIS/FoxO通路参与饮食限制介导的长寿调控，其中FoxO蛋白活性是饮食限制介导寿命延长所必须的。急性电离辐射后，紫扇贝的存活率显著高于海湾扇贝，紫扇贝中DNA损伤修复相关基因ApFoxO、ApPTEN、ApGADD45和ApP53表达水平显著上调，而海湾扇贝中这些基因的表达水平下调，自噬相关基因AiULK2和AiATG8表达水平也呈现显著下调趋势，促凋亡基因AiBcl2表达量显著增加，表明在电离辐射过程中紫扇贝具有更强的抗损伤和修复能力，可能通过激活一定的DNA损伤修复机制维持基因组的完整性，以延缓机体衰老，而海湾扇贝可能由于自身损伤修复机制较弱而启动细胞程序性死亡。
四、利用RNAi技术沉默表达IIS/FoxO通路核心基因IGF1R、PTEN、FoxO的表达，验证这些基因的上下级联关系以及它们在扇贝寿命调控中的作用，并结合GST pull-down联合质谱技术和高通量组学全面分析IIS/FoxO通路在扇贝寿命决定中的调控网络。PTEN的沉默表达导致ApFoxO表达量显著降低，表明扇贝中PTEN正向调控FoxO。FoxO和PTEN沉默表达后，下游抗氧化靶基因SOD和CAT表达水平呈现显著下降趋势，压力抵抗相关基因GADD45和GST以及自噬相关基因ULK2和ATG8的表达水平也显著下调，衰老标志物β-Gal活性显著升高，表明扇贝中FoxO和PTEN协同作用调控机体氧化应激能力，从而正向调控寿命。在抑制IGF1R后，IIS/FoxO通路二级信使Akt和PI3K表达量显著下降，下游效应因子PTEN和FoxO的表达量显著增加，下游靶基因抗氧化酶SOD和CAT活力显著增加，衰老标志物β-Gal的活力显著降低，表明IGF1R与FoxO和PTEN呈上下级联关系，且沉默表达IGF1R可以缓解衰老扇贝体内氧化应激压力，延缓衰老相关参数的变化。下拉蛋白的质谱分析结果显示，凋亡抑制剂BIRC6蛋白、谷胱甘肽过氧化物酶（GSHPx）、DNA损伤修复Rad50蛋白和蛋白酶抑制因子SPINK1蛋白丰度较高。转录组学分析显示，参与扇贝烟酸和烟酰胺代谢中的Sirt、NADK2、NMNAT1和NAMPT，参与泛酸和乙酰CoA代谢中的PANK2以及参与溶酶体降解的LIPA表达量显著上调；同时，差异表达基因富集多条参与寿命调控的信号通路，包括AMPK信号通路、FoxO信号通路、PI3K/Akt信号通路、NF-κB信号通路、Sirt信号通路、DNA损伤响应、P53信号通路以及长寿调节信号通路，表明IIS/FoxO通路可通过与能量代谢相关的AMPK信号通路、表观遗传相关的Sirt信号通路以及营养感应相关的mTOR信号通路相互关联，调节机体氨基酸、cAMP和NAD+水平，以控制抗氧化应激、自噬、DNA修复、免疫、线粒体内稳态以及能量代谢等过程，联合调控扇贝衰老与长寿。
综上所述，本研究首次对IIS/FoxO通路在海湾扇贝和紫扇贝寿命调控中的作用机制进行了深入且详尽的分析，证实了IIS/FoxO通路参与调节扇贝抗氧化应激、DNA损伤修复、自噬与免疫等抗衰老过程。本工作的完成将推进海洋双壳贝类寿命决定分子机制的研究，为其它动物乃至人类寿命决定机制的研究提供新思路，提升对衰老和长寿机制理论的新认知；同时，本工作的完成将会加速扇贝遗传育种进程，为培育长寿命杂交一代扇贝、提高商品规格提供理论依据
中国海岸带海平面上升淹没风险评估及适应性对策研究
No full text在全球气候变化背景下，海平面高度持续上升已经成为普遍共识。海平面上升通过海岸洪水淹没、咸水入侵以及岸线侵蚀等方式对全球海岸带的基础设施维护、土地资源管理、人口安全与生计以及沿海生态系统稳定造成严重的负面影响。中国海岸带作为经济-社会-生态要素高度集聚的重点区域，未来海平面上升带来的淹没风险尤为突出。鉴于此背景，本研究以中国海岸带为研究对象，提出如下科学问题：气候变化背景下，未来时期中国海岸带将在何时何地面临何种程度的海平面上升淹没风险，预期造成何种程度的负面影响，考虑到经济社会发展和自然环境条件的差异，不同地区及行业应采取何种适当且有效的适应性策略？
为解决该问题，本文综合气候科学、地理信息科学、灾害学和区域规划学相关理论和方法开展研究。（1）基于海平面上升多情景模拟数据，构建水文连通性模型，详细分析RCP2.6/RCP4.5/RCP8.5情景下未来时期中国海岸带的海平面上升物理淹没特征，包括淹没范围、面积、水深和频次的时空变化。（2）基于危险性、暴露度&敏感度和适应能力三个维度，优选22个评估指标构建淹没风险评估框架，并应用主客观组合赋权法，分析RCP2.6-SSP1/RCP4.5-SSP2/RCP8.5-SSP5情景下2030、2050和2100年的中国海岸带海平面上升淹没风险及其变化特征。（3）量化分析未来时期不同情景下海平面上升淹没典型风险区对GDP、人口、土地利用/覆被和交通枢纽的预期影响，并以人口、GDP和建成区面积占比为核心指标，探讨未来时期不同情景下经济社会发展水平及其空间分布特征；进一步地，引入耦合协调度模型，分析海平面上升淹没风险与经济社会发展的同步性关系。（4）综合研究结果和国际经验，提出五项适应性对策，旨在为中国海岸带面临的海平面上升挑战提供科学依据和实用策略。研究取得的主要结论如下：
（1）未来时期不同情景下中国海岸带海平面上升淹没区域主要集中在环渤海地区、江苏至长江口沿海地区、珠江三角洲和台湾西部沿海地区，且各情景下淹没范围的空间重心均显示出从西南向东北转移的趋势；不同情景下，中国海岸带理论最大淹没面积呈现波动上升趋势，至2100年，RCP2.6/4.5/8.5情景下淹没面积分别可达4.89万km2、5.05万km2和5.35万km2；在高排放情景下，“深水”和“极深水”的面积和面积占比均显著增加；随着排放情景的上升，地势较高的区域也将面临更加频繁的淹没。
（2）中国海岸带海平面上升淹没“极高”风险区主要集中在辽宁海岸带南部、河北海岸带东部至山东海岸带西北部、胶州湾沿海地区、江苏海岸带北部至中部，以及长江三角洲和珠江三角洲地区，“极低”风险等级的区域则主要分布在海拔较高的内陆山地和丘陵地区；在RCP2.6-SSP1情景下，“极低”风险等级的面积显著增加，显示出随着时间的推移，部分地区的淹没风险将会有所缓解，相比之下，RCP8.5-SSP5情景下，“极高”风险等级的面积急剧增加，突显了中国海岸带在极端气候变化情景下面临着严峻挑战；江苏、上海、广东和天津海岸带“高”和“极高”风险等级的面积占比明显高于其他省份，而福建、浙江和海南海岸带“极低”风险等级的面积占比较高。
（3）在较低排放情景下（RCP2.6-SSP1）中国海岸带海平面上升典型风险区预期影响的GDP在2050年达到峰值，而在更高排放情景下（RCP4.5-SSP2和RCP8.5-SSP5）则在2100年达到峰值；在上述三种情景下，预期影响的人口数量均在2050年达到峰值；“高”淹没风险区预期损失的GDP和人口数量远高于“极高”风险区；不同情景下，广东、浙江、江苏海岸带预期受影响的GDP和人口数量最为显著；广东海岸带预期受影响最大的土地利用/覆被类型为建成区，其次是耕地和内陆水体，而江苏海岸带预期受影响最大的土地利用/覆被类型为耕地，其次是内陆水体和建成区；中国海岸带典型风险区预期影响的港口数量最多，其次是汽车站、火车站和机场，其中，“高”风险区预期影响的汽车站和火车站的数量高于“极高”等级风险区，而港口和机场数量低于“极高”等级风险区。
（4）中国海岸带经济社会发展水平为“高”和“极高”的区域主要集中辽宁海岸带中部、河北海岸带北部、天津海岸带中部、山东海岸带东部、上海海岸带、浙江海岸带东北部和广东海岸带东南部，且经济社会发展重心呈现由西南向东北方向转移趋势，反映了未来时期北方沿海地区经济社会加速发展；在不同情景下，沿海城市的经济社会发展水平呈现出相似的空间分布模式，珠三角地区的深圳和东莞等城市一直保持在“极高”发展水平，上海、嘉兴、汕头、厦门、广州、佛山等城市则保持在“高”发展水平；中国海岸带面临海平面上升淹没风险和经济社会发展水平同步性水平较高的区域主要分布在天津海岸带、江苏海岸带北部、上海海岸带、浙江海岸带北部、福建海岸带东部和南部、广东海岸带中部，特别是，连云港、上海、苏州、嘉兴、厦门、汕头、深圳、东莞、广州、佛山和中山，这些地区或沿海城市在未来时期经济社会发展与海平面上升淹没风险交织密切的问题尤为严重，需要特别关注。
（5）结合上述主要研究结论，从海岸带综合风险管理视角，提出5方面适应性措施，为政府、企业和社区降低海平面上升淹没风险的不利影响提供策略建议，包括：加强基础数据采集共享，提高灾害预警分析水平；分层分级分类应对风险，提升不同产业抵御能力；统筹工程和非工程措施，兼顾发达与欠发达城市；规划点线面体的防灾格局，完善多策略风险应对机制；发展可持续的海岸带经济，促进“双碳”战略目标实现
pH-responsive nanogels with enhanced antioxidant and antitumor activities on drug delivery and smart drug release
No full textpH-responsive nanogels have played an increasingly momentous role in tumor treatment. The focus of this study is to design and develop pH-responsive benzimidazole-chitosan quaternary ammonium salt (BIMIXHAC) nanogels for the controlled release of doxorubicin hydrochloride (DOX) while enhancing its hydrophilicity. BIMIXHAC is crosslinked with carboxymethyl chitosan (CMC), hyaluronic acid sodium salt (HA), and sodium alginates (SA) using an ion crosslinking method. The chemical structure of chitosan derivatives was verified by 1H NMR and FT-IR techniques. Compared to hydroxypropyl trimethyl ammonium chloride chitosan (HACC)-based nanogels, BIMIXHAC-based nanogels exhibit better drug encapsulation efficiency and loading capacity (BIMIXHAC-D-HA 91.76 %, and 32.23 %), with pH-responsive release profiles and accelerated release in vitro. The series of nanogels formed by crosslinking with three different polyanionic crosslinkers have different particle size potentials and antioxidant properties. BIMIXHAC-HA, BIMIXHAC-SA and BIMIXHAC-CMC demonstrate favorable antioxidant capability. In addition, cytotoxicity tests showed that BIMIXHAC-based nanogels have high biocompatibility. BIMIXHAC-based nanogels exhibit preferable anticancer effects on MCF-7 and A549 cells. Furthermore, the BIMIXHAC-D-HA nanogel was 2.62 times less toxic than DOX to L929 cells. These results suggest that BIMIXHAC-based nanogels can serve as pH-responsive nanoplatforms for the delivery of anticancer drugs
pH-responsive nanogels with enhanced antioxidant and antitumor activities on drug delivery and smart drug release
No full textpH-responsive nanogels have played an increasingly momentous role in tumor treatment. The focus of this study is to design and develop pH-responsive benzimidazole-chitosan quaternary ammonium salt (BIMIXHAC) nanogels for the controlled release of doxorubicin hydrochloride (DOX) while enhancing its hydrophilicity. BIMIXHAC is crosslinked with carboxymethyl chitosan (CMC), hyaluronic acid sodium salt (HA), and sodium alginates (SA) using an ion crosslinking method. The chemical structure of chitosan derivatives was verified by 1H NMR and FT-IR techniques. Compared to hydroxypropyl trimethyl ammonium chloride chitosan (HACC)-based nanogels, BIMIXHAC-based nanogels exhibit better drug encapsulation efficiency and loading capacity (BIMIXHAC-D-HA 91.76 %, and 32.23 %), with pH-responsive release profiles and accelerated release in vitro. The series of nanogels formed by crosslinking with three different polyanionic crosslinkers have different particle size potentials and antioxidant properties. BIMIXHAC-HA, BIMIXHAC-SA and BIMIXHAC-CMC demonstrate favorable antioxidant capability. In addition, cytotoxicity tests showed that BIMIXHAC-based nanogels have high biocompatibility. BIMIXHAC-based nanogels exhibit preferable anticancer effects on MCF-7 and A549 cells. Furthermore, the BIMIXHAC-D-HA nanogel was 2.62 times less toxic than DOX to L929 cells. These results suggest that BIMIXHAC-based nanogels can serve as pH-responsive nanoplatforms for the delivery of anticancer drugs