Diversity surveys of soil bacterial community by cultivation--based methods and molecular fingerprinting techniques

By combining the cultivation methods with molecular fingerprinting techniques, the diversity surveys of soil bacterial community in 13 areas of China were carded out. The cultivable heterotrophic diversity was investigated by colony morphology on solid LB medium. Genetic diversity was measured as bands on denaturing gradient gel electrophoresis(DGGE) by the extraction and purification of the total soil DNA, and amplification of bacterial 16S rDNA fragments by polymerase chain reaction(PCR). The Shannon-Wiener indices of diversity(H), richness(S) and evenness(EH) were employed to estimate the diversity of soil bacterial community. The results showed that there was an obvious diversification existed in soil from the different areas. However, the genetic diverslty estimated by PCR-DGGE can provide more comprehensive information on bacterial community than the cultivation-based methods. Therefore, it is suggested to combine the traditional methods with genetic fingerprinting techniques to survey and estimate soil bacterial diversity.     

Long-term exposure to air pollution and cerebrovascular disease: findings from Beijing Health Management Cohort study

● This study explored the long-term association by double robust additive models. ● Individual exposure concentrations were assessed by integrating GAM, LUR and BPNN. ● PM_2.5, SO₂ and NO₂ are positively associated with cerebrovascular disease. ● CO could reduce the risk of cerebrovascular disease with the highest robustness. ● The elderly, women and people with normal BMI are at higher risk for air pollution. The relationship between air pollution and cerebrovascular disease has become a popular topic, yet research findings are highly heterogeneous. This study aims to investigate this association based on detailed individual health data and a precise evaluation of their exposure levels. The integrated models of generalized additive model, land use regression model and back propagation neural network were used to evaluate the exposure concentrations. And doubly robust additive model was conducted to explore the association between cerebrovascular disease and air pollution after adjusted for demographic characteristics, physical examination, disease information, geographic and socioeconomic status. A total of 25097 subjects were included in the Beijing Health Management Cohort from 2013 to 2018. With a 1 μg/m³ increase in the concentrations of PM_2.5, SO₂ and NO₂, the incidence risk of cerebrovascular disease increased by 1.02 (95% CI: 1.008–1.034), 1.06 (95% CI: 1.034–1.095) and 1.02 (95% CI: 1.010–1.029) respectively. Whereas CO exposure could decrease the risk, with an odds ratio of 0.38 (95% CI: 0.212–0.626). In the subgroup analysis, individuals under the age of 50 with normal BMI were at higher risk caused by PM_2.5, and SO₂ was considered more hazardous to women. Meanwhile, the protective effect of CO on women and those with normal BMI was stronger. Successful reduction of long-term exposure to PM_2.5, SO₂ and NO₂ would lead to substantial benefits for decrease the risk of cerebrovascular disease especially for the health of the susceptible individuals.     

生物水解（酸化）法处理高浓度洁霉素废水的降解机理研究

在应用生物水解（酸化）法处理高浓度洁霉素生产废水中试试验中,着重研究水解（酸化）反应中起主要作用的微生物菌群及其降解效率。同时采用GPC（凝胶渗透色谱）、GC/MS（色谱一质谱）等分析手段对水解（酸化）反应过程中有机物形态变化进行研究。结果表明,在水解（酸化）反应中起主要作用的有埃希氏菌属、发酵单胞菌属、气单胞菌属、变形杆菌属、柠檬酸杆菌属等。同时,水解（酸化）反应具有将洁霉素废水中的大分子有机物降解为小分子有机物的作用,可提高废水的可生化性。     

Energy and Economic flow in homegardens in Subtropical Yunnan,SW China: A case study on Sanjia village

We studied the energy and economic flow of six types of homegardens in Sanjia village, SW China. Our study showed that the energy input of six types of homegardens averaged 99.11-175.65 x 10¹⁰J/ha, the energy output was 102.30-159.83 x 10¹⁰J/ha and the ratio of input/output ranged between 1:0.880-1:1.416. The ratios of input to output of home-gardens that prioritized cultivation of crops were higher than for homegardens that prioritized animal husbandry or other economic activities. The economic ratio of input/ output of six types of homegardens varied between 1:0.997-1:1.376 and the economic output ranged between 2480.0-10131.5 RMB/yr. We concluded that the homegarden systems of Sanjia village are high in the input and output of energy and cash flow, and can provide a basis for designing models of farm economy in rural subtropical areas.     

pH、温度及初始铊浓度对硫酸盐还原菌脱铊的影响

环境因素对硫酸盐还原菌除铊效果具有较大的影响。在对上流式厌氧污泥床污泥中分离纯化得到的硫酸盐还原菌进行初步鉴定的基础上,探讨pH、温度以及初始铊浓度对硫酸盐还原菌除铊效果的影响。实验结果表明,3株耐铊硫酸盐还原菌生长的反应适宜pH为6.0,该pH环境下3个菌株的铊去除率分别为96.71%、97%和96.23%;最适温度在28~32℃范围内,此条件下3株菌株对铊的去除率分别高达93.11%、91.84%和92.83%;初始低浓度铊对菌株除铊效果影响较小,3株菌株除铊率均达到99.4%以上。对反应过程中的pH、温度以及初始铊浓度进行调节,对于改善硫酸盐还原菌去除铊污染效果具有重要意义。     

Modelling tritrophic interactions mediated by induced defence volatiles

Many plant species defend themselves against herbivorous insects indirectly by producing and releasing induced volatiles to attract natural enemies of the herbivores. In this paper, we consider the recruitment of natural enemies attracted by plant-induced volatiles and introduce the An–Liu–Johnson–Lovett model into the Lotka–Volterra model in an attempt to add this missing vital link in tritrophic interaction. Increase in attraction strength of plant-induced volatiles to the natural enemy leads to high fluctuation amplitude of plant biomass and herbivore population. When the attack strength of natural enemies reaches a certain level, fluctuation amplitude of plant biomass and herbivore population will decrease and plant biomass will approach to its environmental carrying capacity. The simulation demonstrates that plant volatile compounds induced by insects have led to the introduction of a third tritrophic level, e.g., natural enemies, into the plant–herbivore system, resulting in the coexistence of plants, insects, and natural enemies during the evolution process.     

鱼类加工废水絮凝床─SBR处理技术的应用

在鱼类加工废水蛋白质资源回收利用基础上,应用絮凝床预处理技术（ＣＦＢ） Ｅ以简单的ＳＢＲ生化法成功地处理了该类废水,实验表明,以ＣＦＢ技术为主线开发的鱼类加工废水处理工艺,具有技术先进、处理效果好、运行稳定可靠、管理简便、经济实用等特点,在实际应用中有广阔的前景。     

土壤-植物系统中氮锌交互作用研究进展

对几十年来有关土壤-植物系统氮锌交互作用研究现状及未来趋势进行了综述。论述了氮锌交互作用与植物生长、氮锌及其它元素的吸收、转运、积累的相互关系,以及对微生物生长及豆科作物固氮的影响;讨论了氮锌交互作用的生理生化基础及细胞亚细胞学机理;指出了氮锌交互作用的若干薄弱环节;展望了氮锌交互作用未来的研究方向。     

高锰酸钾预氧化后地表水中三氯甲烷生成量的预测模型研究

在饮用水处理中,适当地采用高锰钾预氧化可以降低水中的三氯甲烷生成量。本文研究了影响三氯甲烷生成量的因素,如反应时间,反应温度等,并以这些影响因素为参数通过一元线性回归等数学方法,建立了各影响因素下三氯甲烷生成量折了模型和综合预测模型。     

南亚热带丘陵土壤水分循环及其有效性的研究──Ⅲ.降雨入渗与地表径流

南亚热带高温多雨,年降雨量大而分布不均,台风雨季节降雨强度大,全年降雨多集中在4～9月,占全年的80％以上,因而大大地增加了降雨所引起的地表径流,径流也主要集中在多雨季节,特别是在5～8月,占全年降雨径流量的90％左右,形成了南亚热带坡地独特的地表径流特征．南亚热带的降雨入渗对表土层的影响较大,在暴雨过程中,0～30cm土层水分易产生饱和,因而易产生地表径流,从而减少水分入渗．这对作物生长产生不利的影响．