Sewage sludge processing determines its impact on soil microbial community structure and function

Composting and thermal drying are amongst the most commonly used post-digestion processes for allowing sanitation and biological stabilization of sewage sludge from municipal treatment plants, and making it suitable as soil conditioner for use in agriculture. To assess the impact of sludge-derived materials on soil microbial properties, fresh (LAF), composted (LAC) and thermally dried (LAT) sludge fractions, each resulting from a different post-treatment process of a same aerobically digested sewage sludge, were added at 1% (w/w) application rate on two contrasting (a loam and a loamy sand) soils and incubated under laboratory conditions for 28 days. Soil respiration, microbial ATP content, hydrolytic activities and arginine ammonification rate were monitored throughout the incubation period. Results showed that soil biochemical variables, including the metabolic quotient (qCO₂), were markedly stimulated after sludge application, and the magnitude of this stimulatory effect was dependent on sludge type (precisely LAT > LAF > LAC), but not on soil type. This effect was related to the content of stable organic matter, which was lower in LAT. Genetic fingerprinting by PCR–DGGE revealed that compositional shifts of soil bacterial and, at greater extent, actinobacterial communities were responsive to the amendment with a differing sludge fraction. The observed time-dependent changes in the DGGE profiles of amended soils reflected the microbial turnover dependent on the sludge nutrient input, whereas no indications of adverse effects of sludge-borne contaminants were noted. Our findings indicate that composting rather thermal drying can represent a more appropriate post-digestion process to make sewage sludge suitable for use as soil conditioner in agriculture.     

氮添加对天山高寒草原土壤酶活性和酶化学计量特征的影响

为探究氮添加对高寒草原生态系统土壤酶活性的影响,于2018年在中国科学院巴音布鲁克草原生态系统研究站,选择4个氮添加水平(对照,N0,0 kg·hm^-2·a^-1;低氮,N1,10 kg·hm^-2·a^-1;中氮,N3,30 kg·hm^-2·a^-1;高氮,N9,90 kg·hm^-2·a^-1),开展土壤酶活性对氮添加响应的研究,分析土壤酶活性对氮添加的响应特点,土壤酶化学计量比以及土壤酶活性与土壤环境因子的关系。结果表明:与对照相比,氮添加在N3水平显著增加β-1,4葡萄糖苷酶(βG)、β-D-纤维二糖水解酶(CBH)和β-1,4木糖苷酶(βX)酶活性(P<0.05),N1和N3水平显著增加碱性磷酸酶(AKP)活性(P<0.05),N3水平显著降低多酚氧化酶(PPO)活性(P<0.05),氮添加对亮氨酸氨基肽酶(LAP)活性影响不显著,N3水平下显著增加N-乙酰-β-D氨基葡萄糖苷酶(NAG)活性(P<0.05)。相关分析表明,8种土壤酶活性均与土壤有机碳(SOC、NAG除外)和总磷(TP)显著相关,与土壤总氮(TN)不相关。研究区土壤酶活性C∶N∶P化学计量比为1∶1∶1.2,与全球生态系统的土壤酶活性C∶N∶P的比值1∶1∶1相偏离,表明该研究区土壤微生物生长受磷素限制。冗余分析(RDA)进一步揭示出土壤有机碳和土壤全磷含量是影响土壤酶活性的主要因子。     

论孔子的休闲活动及休闲理念

孔子不仅是我国的思想家和教育家，而且还是一位善于休闲的大家。孔子一生有着丰富的休闲活动，且其休闲活动蕴含着颇有价值的休闲理念。孔子认同并践行休闲活动，并在休闲实践中用礼制教化和休闲淡然的方式规范休闲，提倡人与自然和谐的休闲理念，继而在休闲中发展了休闲的美学、哲学意境。孔子的休闲活动及休闲理念对于我们今天的休闲有着启示和借鉴的作用。     

煮熟和干燥处理对黄藤笋抗氧化活性的影响

通过测定黄藤熟笋、生笋(鲜切笋)、熟笋干和生笋干的水和4种不同浓度乙醇提取物中的自由基清除能力、总还原能力、总多酚含量和总黄酮含量,研究了煮熟、干燥加工方法对黄藤笋提取物抗氧化活性的影响。结果表明,煮熟处理能保持或提高提取物的抗氧化活性,干燥处理则相反。乙醇提取物比水提取物具有更高的抗氧化活性,以50%~75%的乙醇提取溶剂效果最好。熟笋在所有溶剂中的自由基清除能力、总还原能力、总多酚含量和总黄酮含量均表现出最高水平,表明煮熟是黄藤笋适宜的加工利用方式。     

危害沙棘的围连环夜蛾生物学特性及防治

围连环夜蛾在我国多有分布，但看见其幼虫的还是很少，因资料中寄主不祥，笔者经室内外观察。发现其危害多种植物的叶片，更喜欢危害沙棘树的叶片，笔者经2a的室内外观察得知。其生物学特性在辽宁西部每年1代，以蛹越夏及冬。对沙棘树危害较重，对栽植的大果沙棘危害尤为严重，在5a生的沙棘树上有100多头幼虫危害，成虫善飞翔。     

长蒴黄麻总黄酮的提取及其抗氧化性

为长蒴黄麻的开发利用提供参考依据,对超声波协同乙醇提取长蒴黄麻黄酮的效果进行了研究,并进行了长蒴黄麻黄酮的抗氧化性试验.结果表明,最优提取条件为温度42℃、料液比1∶35、乙醇浓度80％、提取时间25min,在此条件下长蒴黄麻总黄酮的提取率为2.577％.长蒴黄麻黄酮提取物对羟基自由基和超氧阴离子自由基具有一定的清除作...     

Comparison of phenolic profiles and antioxidant activities in skins and pulps of eleven grape cultivars(Vitis vinifera L.)

Eleven grape cultivars were analysed to explore the variety differences of fresh grape phenolic profiles. The results showed that free phenolics were predominant in grape skins and pulps, and showed the higher antioxidant activities than bound. In 11 cultivars, Muscat Kyoho extracts had the highest total phenolic content in skins(10.525 mg GAE g~(–1) FW) and pulps(1.134 mg GAE g~(–1) FW), and exhibited the highest DPPH radical scavening capacity(EC_(50)=11.7 μg mL~(–1)) and oxygen radical absorbance capacity(ORAC) value(190.57 μmol TE g~(–1) FW) of free phenolic in skin. In addition, the most abundant phenolics in grape skins were found to be flavonoids such as kaempferol in Kyoho skin(541.2 μg g~(–1) FW), rutin, catechin and epicatechin in Muscat Kyoho skin(262.3, 86.3 and 70.0 μg g~(–1) FW, respectively). Furthermore, the principal component analysis showed a strong difference of phenolic profiles with the cultivars, existing forms and distributions. Pearson correlation coefficient analysis showed a significant linear correlation between total phenolic content and antioxidant activity(P0.05). Therefore, both skins and pulps were rich sources of bioactive phenolic compounds, and Muscat Kyoho was the ideal source among all samples.     

柱层析法对菌株snef8有效成分的初步分离

采用硅胶柱层析的方法,对snef8菌株中的杀线虫活性物质进行了初步的分离,生物法测定各组份的杀线虫活性,减压浓缩有活性的组份制备粗提液.结果表明:菌液中的杀线虫活性物质主要集中于第8～第12号管中,其杀线虫活性接近于100%.此法不但可以除去部分杂质,提高粗提液的纯度,还可以应用制备型硅胶柱,大量制备富集粗提液,将其作...     

核桃枝枯病病原菌鉴定及其生物学特性

In May 2018,a new shoot dieback disease was found in several walnut orchards in Rizhao,Shandong Province.The fungal pathogen was obtained on PDA plate from diseased walnut shoots using a tissue isolation method.The purified fungal isolates formed white to grey colonies on PDA plate and three single spore isolates SDWa1-SDWa3 were obtained.Based on morphological characteristics and analysis of rDNA internal transcribed spacer (ITS),calmodulin (CAL),translation elongation factor 1-α (TEF1) and β-tubulin (TUB) sequences,the fungal isolates were identified as Diaporthe nobilis,a new pathogen on walnut.The test of Koch's rule confirmed that D.nobilis was the pathogen of walnut shoot dieback.To determine optimal growing conditions for the pathogen,its biological characteristics test was conducted.The results showed that the optimal growth temperature and pH value were at 25℃ and pH 5-9,respectively.The optimum carbon source was glucose,and favourable nitrogen source was peptone.     

黑蜣(Bess beetle)纤维素酶的组分及其特性分析

以30日龄的黑蜣幼虫为材料,对其整体匀浆后组织液中的纤维素酶组成及活性进行了分析。结果表明:黑蜣体内存在内切β-1,4-葡聚糖酶(Cx酶)、β-葡萄糖苷酶;β-葡萄糖苷酶和Cx酶的最适宜温度为分别为40℃和50℃;Cx酶和β-葡萄糖苷酶分别在pH值为6.4和5.2时具有最大的活力;β-葡萄糖苷酶和Cx酶的最适宜反应时间为80 min。Cx酶具有比β-葡萄糖苷酶更强的温度适应性,在30～50℃温度范围内可维持最大酶活力的66.20%。