草甘膦对旋链角毛藻和盐生杜氏藻的毒性兴奋效应(Stimulation Effect of Glyphosate on Chaetoceros curvisetus and Dunallelia salina)

为研究农药对海洋微藻的毒性兴奋效应(低剂量刺激生长效应),实验测定了不同时间点、不同剂量草甘膦(Glyphosate)对旋链角毛藻(Chaetoceros curvisetus)和盐生杜氏藻(Dunallelia salina)生长的影响,并使用Log-Logistic修正模型和三维模型对实验结果进行拟合.结果表明,草甘膦对两种海洋微藻均存在不同程度的刺激生长效应,修正的Log-Logistic生长模型和三维模型拟合结果不存在显著性差异,但由于不需编程且能得到更多参数,因此使用Log-Logistic修正模型能够更好地描述草甘膦对藻类的剂量-反应结果.     

The impact of different voltage application modes on biodegradation of chloramphenicol and shift of microbial community structure

● Presented coupled system enhanced biodegradation of antibiotic chloramphenicol. ● HRT and electrical stimulation modes were key influencing factors. ● Electrical stimulation had little effect on the chloramphenicol metabolic pathway. ● Microbial community structure varied with the voltage application mode. Exoelectrogenic biofilms have received considerable attention for their ability to enhance electron transfer between contaminants and electrodes in bioelectrochemical systems. In this study, we constructed anaerobic-aerobic-coupled upflow bioelectrochemical reactors (AO-UBERs) with different voltage application modes, voltages and hydraulic retention times (HRTs). In addition, we evaluated their capacity to remove chloramphenicol (CAP). AO-UBER can effectively mineralize CAP and its metabolites through electrical stimulation when an appropriate voltage is applied. The CAP removal efficiencies were ~81.1%±6.1% (intermittent voltage application mode) and 75.2%±4.6% (continuous voltage application mode) under 0.5 V supply voltage, which were ~21.5% and 15.6% greater than those in the control system without voltage applied, respectively. The removal efficiency is mainly attributed to the anaerobic chamber. High-throughput sequencing combined with catabolic pathway analysis indicated that electrical stimulation selectively enriched Megasphaera, Janthinobacterium, Pseudomonas, Emticicia, Zoogloea, Cloacibacterium and Cetobacterium, which are capable of denitrification, dechlorination and benzene ring cleavage, respectively. This study shows that under the intermittent voltage application mode, AO-UBERs are highly promising for treating antibiotic-contaminated wastewater.     

不同强度的声波对猕猴桃试管苗根系发育的影响

通过用不同强度的声波刺激中华猕猴桃(Actinidia chinensis)的组培试管苗，研究模拟声场的力学刺激对木本植物根系发育的生物学效应．结果表明：适度强度的声波刺激(100dB左右)可促进猕猴桃试管苗根系的生长发育，而根系质膜的通透性也相应降低以阻挡外界有害物质的侵入，使根系活力以及与之相关的根系总长、分根数等指标明显增强；但当声波强度超过一定范围后，对根系发育的促进效应就受到明显的抑制，当110dB时甚至开始抑制试管苗的根系发育．从细胞和分子生物学水平对环境应力影响根系发育的可能机理进行了讨论．图2表1参13     

电刺激条件下初始pH值对剩余污泥厌氧消化效果的影响

在厌氧消化反应器中施加0.6V电压刺激,考察初始pH值(3,5,7,9,11)对剩余污泥厌氧消化效果的影响.结果表明,当初始pH值为9、厌氧消化至32d时,污泥挥发性固体有机物去除率为38.1%,甲烷产率为224mLCH₄/g VS;同样的消化时间内,初始pH值为7的对照组,其挥发性固体有机物去除率为32.2%,甲烷产率仅为162mLCH₄/g VS.调节初始pH值可加速污泥水解酸化过程,其中pH值为11时,水解酸化效果最好,比其他pH值条件下产生更多的挥发性脂肪酸(VFAs).在产酸高峰期,初始pH值为3、11时,乙酸和丁酸是主要产物;初始pH值为5、7、9时,主要产物是乙酸和丙酸.调节初始pH值能加速氨氮的释放,且pH值为酸性(3,5)时的氨氮浓度高于碱性条件下(9,11)的浓度.     

金属离子对好氧活性污泥活性的影响

通过小试装置研究Mg2 、Mn2 、Ni2 、Zn2 、Co2 和Mo6 单独存在时对活性污泥活性的影响.结果发现,Co2 浓度在2 mg/L以下时,对活性污泥活性稍有抑制,其他离子则均有促进作用.Mn2 、Mo6 、Zn2 、Mg2 和Ni2 的促进浓度范围分别是:0.5～3 mg/L,0.5～5 mg/L,0.5～1 mg/L,5～20 mg/L,0.25～1 mg/L.在各自最佳浓度条件下对活性污泥活性促进的主次顺序为:Mg2 ＞Mn2 ＞Zn2 ＞Ni2 ＞Mo6 .     

应急场景下矿工脑电成分特征的实验研究

为探究矿工在应急场景下的脑电成分变化规律,研究通过脑电实验的方法对矿工在观看应急与正常作业场景下文字与图片素材的脑电数据进行分析.结果表明:矿工在实验素材的靶刺激下,ERP成分明显,且图片刺激效果强于文字,在200～400 ms时,P200,P300成分峰值最大;矿工大脑α节律不断下降,β节律不断上升,且β节律波幅面积...     

化感物质对土壤脲酶活性的影响

研究不同的化感物质ＦＡ,４－ｔ－ＢＡ,ＢＨ的不同浓度及其混合物对土壤脲酶活性的影响。研究结果表明,３种化感物质对土壤脲酶活性均有一定的刺激作用,其中４－ｔ－ＢＡ刺激作用最强,但持续时间短;ＢＨ的刺激作用弱,但持续时间长,不同化感物质对脲酶活性的最大刺激点随时间的不同而不同,其中４－－ＢＡ的５００ｍｇ．ｋｇ＾－１和ＢＨ的２００ｍｇ．ｋｇ＾－１均在第７ｄ,而ＦＡ的５００ｍｇ．ｋｇ＾－１在第display stru     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

Establish the Long-effective Mechanism of Food Security in China

In despite of fluctuation in recent years, the grain yield in China has been increasing, which relieves the conflict between supply and demand and turns the situation of food security good. However, because of the rapid increase in food consumption, the conflicts of food quality and structure in the supply and demand equilibrium has become more and more obvious and the long-effective mechanism of food security has not been established yet. It is found that the factors affecting food security in China include the scarcity and dissipation of resources, farmers＇ low enthusiasm in planting grain crops and the inappropriateness of the emphasis and measures of macro-economic regulation and control. Therefore, the authors advance to optimize resources allocation, strengthen macro-economic regulation and control and policy stimulation and establish the mechanism of allocating grain production cost, to set up the long-effective mechanism of China food security and keep it stable in the long term.     

Establish the Long-effective Mechanism of Food Security in China

Abstract

In despite of fluctuation in recent years, the grain yield in China has been increasing, which relieves the conflict between supply and demand and turns the situation of food security good. However, because of the rapid increase in food consumption, the conflicts of food quality and structure in the supply and demand equilibrium has become more and more obvious and the long-effective mechanism of food security has not been established yet. It is found that the factors affecting food security in China include the scarcity and dissipation of resources, farmers’ low enthusiasm in planting grain crops and the inappropriateness of the emphasis and measures of macro-economic regulation and control. Therefore, the authors advance to optimize resources allocation, strengthen macro-economic regulation and control and policy stimulation and establish the mechanism of allocating grain production cost, to set up the long-effective mechanism of China food security and keep it stable in the long term.