Resource utilization conditions as biochar of an invasive plant Spartina alterniflora in coastal wetlands of China

Converting feedstocks of invasive plants into biochar is a new and cost‐effective measure for their control, and benefits for the sustainable development of native ecosystems. Spartina alterniflora, an invasive plant widely distributed in coastal wetlands of China, was used to produce biochar. We aimed to analyze how S. alterniflora biochar properties changed with desalination of feedstocks, pyrolysis temperature, and residence time. Results showed that desalting feedstocks increased biochar pH, stability, porosity, and surface area, but diminished biochar yield and polarity. Pyrolysis temperature positively affected biochar pH, surface area, and pore volume, while it had negative effects on biochar yield, oxygen and hydrogen contents, hydrogen/carbon and oxygen/carbon ratios, pore size, and function groups. However, residence time of pyrolysis had slight effects on biochar properties. The results are valuable for optimizing pyrolysis temperature and pretreatment measure of feedstocks, to tune S. alterniflora biochar properties for specific environmental usage.     

Structure-activity relationships study of neolamellarin A and its analogues as hypoxia inducible factor-1 (HIF-1) inhibitors

The novel marine pyrrole alkaloid neolamellarin A derived from sponge has been shown to inhibit hypoxia-induced HIF-1 activity. In this work, we designed and synthesized neolamellarin A and its series of derivatives by a convergent synthetic strategy. The HIF-1 inhibitory activity and cytotoxicity of these compounds were evaluated in Hela cells by dual-luciferase reporter gene assay and MTT assay, respectively. The results showed that neolamellarin A 1 (IC₅₀ = 10.8 ± 1.0 μM) and derivative 2b (IC₅₀ = 11.9 ± 3.6 μM) had the best HIF-1 inhibitory activity and low cytotoxicity. Our SAR research focused on the effects of key regions aliphatic carbon chain length, aromatic ring substituents and C-7 substituent on biological activity, providing a basis for the subsequent research on the development of novel pyrrole alkaloids as HIF-1 inhibitors and design of small molecule probes for target protein identification.     

连翘提取物对嗜水气单胞菌群体感应系统的影响

【背景】传统抑菌剂的大量使用导致细菌产生多重耐药性与抗性,而基于细菌群体感应靶点调控的新型抑菌剂可缓解细菌耐药性与抗性,是未来抑菌剂的发展方向之一。【目的】研究连翘(Forsythiasuspensa)提取物对嗜水气单胞菌(Aeromonashydrophila)群体感应系统的影响及可能的作用机制,为新型抑菌剂的开发提供理论依据。【方法】以紫色杆菌(Chromobacterium violaceum)CV026为报告菌株,以嗜水气单胞菌为供试菌株,采用倍比稀释法测定连翘提取物对2种菌的最小抑菌浓度(minimal inhibitory concentration,MIC),通过微量法测定提取物对嗜水气单胞菌生长、群集运动及蛋白酶活性的影响,利用高效液相色谱串联质谱法分析提取物中的主要成分,采用分子对接模拟探究提取物对嗜水气单胞菌群体感应系统的作用机制。【结果】连翘提取物对紫色杆菌CV026和嗜水气单胞菌的MIC均为16.00mg/mL。在亚抑菌浓度下,连翘提取物处理显著抑制了CV026紫色菌素的产生,最大抑制率高达56.30%。经8.00mg/mL连翘提取物处理后,嗜水气单胞菌的群集运...     

耐高浓度氨氮的异养硝化好氧反硝化菌株U1的鉴定及其脱氮特性

【背景】城市垃圾渗滤液是一种成分复杂的有机废水,含氮量高,如果未经处理直接排放到环境中会造成严重的环境污染。【目的】筛选可以耐受垃圾渗滤液中高浓度氨氮并高效去除污水中氮素的异养硝化好氧反硝化菌株,为解决垃圾渗滤液的氮素污染提供功能菌株。【方法】从垃圾渗滤液中筛选分离能耐受高氨氮浓度的菌株,通过测定各菌株的脱氮能力,筛选到一株脱氮能力最强的菌株,命名为U1,通过测定16S rRNA基因序列和生理生化特性确定该菌株为铜绿假单胞菌。进一步研究了菌株U1在不同初始氨氮浓度、碳源、转速、初始pH、碳氮比等单因素变量下的脱氮能力,并结合L₉（3⁴）正交试验研究了菌株U1的最佳脱氮条件。【结果】分离出一株铜绿假单胞菌并命名为U1。该菌株的最优脱氮条件为:初始氨氮浓度为1 000 mg/L,红糖和柠檬酸三钠的混合碳源,pH 6.0,C/N为10,转速为130 r/min,菌株U1的最大总氮去除率为64.37%,最大氨氮去除率为76.73%。对于总氮和氨氮含量分别是2 345 mg/L和1 473.8 mg/L的垃圾渗滤液,菌株U1最大总氮去除率为27.86%...     

Metagenomic analysis for the microbial consortium of anaerobic CO oxidizers

Metagenomics analysis has been applied to identify the dominant anaerobic microbial consortium of the carbon monoxide (CO) oxidizers in anaerobic sludge. Reads from the hypervariable V6 region in the bacterial 16s rDNA were aligned and finally clustered into operational taxonomic units (OTUs). The OTUs from different stages in anaerobic CO condition were classified. Alphaproteobacteria, clostridia, betaproteobacteria and actinobacteria were the most abundant groups, while alphaproteobacteria, betaproteobacteria and actinobacteria were variable groups. CO consumption and production efficiency of the microbial consortium were studied. Semi-continuous trials showed that these anaerobic CO oxidizers formed a stable microbial community, and the CO conversion rate was at over 84%, with the highest CO consumption activity of 28.9 mmol CO/g VSS●day and methane production activity at 7.6 mmol CH₄/g VSS●day during six cycles.