Degradation products of polycondensed aromatic moieties (black carbon or pyrogenic carbon) in soil: Methodological improvements and comparison to contemporary black carbon concentrations

It was found that benzenepolycarboxylic acids (BPCA) do naturally occur in soils. They can be assumed as black carbon degradation products. We propose an improved method to analyse black carbon degradation products in soil. Method optimization comprised extraction duration, sample clean‐up, and chromatographic separation conditions. The method is also suitable for subsequent isotope ratio mass spectrometry of individual BPCA. Accuracy was checked with quartz sand and soil samples spiked with known amounts of BPCA. In soil samples with varying properties we compared contents of black carbon and black carbon degradation products, i.e., total and free BPCA contents, respectively. Results show that our proposed method can extract black carbon degradation products from soil after 48 h of extraction with 500 mM NaOH compared to 72 h of the original method. Polyvalent cations should be removed by Dowex 50 W X 8, 200–400 mesh, while original cation removal with Merck cation exchange resin was not successful. Free BPCA can be separated and quantified directly by ion exchange chromatography followed by ultraviolet spectroscopy or isotope ratio mass spectrometry, while the original method involved another two days for derivatization and isolation of derivatized BPCA. Recovery of spiked BPCA to a range of different soil samples was 81 ± 19%. Free BPCA concentrations of a Cambisol, Chernozem, Ferralsol, and Anthrosol varied between 0 and 0.24 g kg^?1 contributing 0–38% of total black carbon concentration. Free BPCA correlated with total black carbon, total organic carbon, and negatively with pH. However, further studies with a larger set of samples are necessary to systematically investigate conditions for black carbon degradation and, thus free BPCA formation in soils.     

小鼠骨髓源CD103+DC分离培养及LPS对其形态与功能特征的影响

旨在建立C57BL/6小鼠骨髓源CD103⁺树突状细胞(CD103⁺ dendritic cell,CD103⁺DC)分离培养方法,阐述LPS对其形态与功能特征的影响。在无菌条件下分离C57BL/6小鼠骨髓细胞,并用重组GM-CSF和FLT3L对其进行体外联合诱导培养;利用光镜、扫描电镜、荧光显微镜和流式细胞术,分别对LPS作用前后细胞形态、表型及功能进行了分析。结果表明,细胞培养至第3天有零星集落出现,第13天后集落开始分散,可见典型的树突状突起,第15天后可得到大量的CD103⁺DC,加LPS刺激培养24 h后细胞表面树突样结构更加明显;分离培养的骨髓细胞能够表达表面分子CD103,其表达率达90%以上。RPMI-1640组(LPS未刺激组)可吞噬VOA的CD103⁺DC比例为25.70%,能够表达MHC-Ⅱ和CD83阳性细胞分别为41.31%和13.79%;LPS刺激组可吞噬VOA的CD103⁺DC比例为10.33%,能够表达MHC-Ⅱ和CD83的阳性细胞分别为68.10%和24.71%。MTT法检测结果显示,经LPS处理的CD103⁺DC刺激T细胞增殖的能力明显增强。综上所述,分离于C57BL/6小鼠的骨髓细胞,可在体外经FLT3L和GM-CSF共同诱导培养出CD103⁺DC,LPS可促进CD103⁺DC的成熟。     

尿素和生物质炭对茶园土壤pH值及CO2和CH4排放的影响

为明确生物质炭对酸化茶园土壤改良及温室气体排放的影响,利用室内培养试验,研究了在施氮(N1)和不施氮(N0)条件下,不同小麦秸秆生物质炭添加量(B1,10 g·kg~(-1);B2,30 g·kg~(-1);B3,50 g·kg~(-1))对茶园土壤pH值、CO_2和CH_4排放的影响。结果表明,添加生物质炭显著提高了茶园土壤pH值(P0.05),生物质炭施加比例越高,土壤pH值提高幅度越大,处理组N0B1、N0B2和N0B3土壤平均pH较对照组CK(氮和生物质炭都不施)分别提高了0.18、0.53、1.06个单位,生物质炭添加量为3%(B2)时,短期内可达到提高土壤pH值、改良酸化土壤的效果;CO_2和CH_4的累积排放量随着生物质炭添加比例的升高而增大,且显著高于对照组CK(P0.05)。施加尿素短期内显著提高了土壤pH值(P0.05),并促进了CO_2的排放,但对CH_4的排放无显著影响。与单施生物质炭相比,生物质炭与尿素共施时土壤pH提高幅度更大,CO_2累积排放量提高程度也更为显著,而CH_4的排放得到抑制,但仍显著高于对照组CK(P0.05)。生物质炭的添加在提高土壤pH值的同时也会增加CO_2和CH_4的排放量,增大环境风险,但当土壤酸化程度较轻时,可适当施加低量生物质炭,在缓解土壤酸化状况的同时尽可能地减少温室气体的排放量。     

颗粒密度对垃圾衍生燃料燃烧特性的影响

垃圾衍生燃料(RDF,refuse derived fuel)是垃圾焚烧发电的原料,该文研究RDF预加工的形态对其燃烧释放能量过程的影响。将RDF制备成不同密度等级的成型颗粒,通过热重、热值、灰分分析,同时参比与非成型的RDF和生物质秸秆燃料,观察RDF成型颗粒燃烧特性。研究结果表明,该组非成型RDF的着火点为234.0℃,3个最大失质量速率分别为6.30,2.21,0.53%min;高密度RDF的着火点为238.2℃,3个最大失质量速率分别为5.70,3.11,0.61%/min,表明较高密度RDF颗粒在燃烧过程中,着火点较高,燃烧速率较为均衡。该组高密度RDF比非成型RDF燃烧后的灰渣少6.7%,表明高密度RDF燃烧较为充分。在热值方面,方差显著性分析表明,RDF颗粒密度值对其燃烧产生的热值无明显影响。     

Paddy management on different soil types does not promote lignin accumulation

Paddy soil management is generally thought to promote the accumulation of soil organic matter (SOM) and specifically lignin. Lignin is considered particularly susceptible to accumulation under these circumstances because of the recalcitrance of its aromatic structure to biodegradation under anaerobic conditions (i.e ., during inundation of paddy fields). The present study investigates the effect of paddy soil management on SOM composition in comparison to nearby agricultural soils that are not used for rice production (non‐paddy soils). Soil types typically used for rice cultivation were selected, including Alisol, Andosol and Vertisol sites in Indonesia (humid tropical climate of Java) and an Alisol site in China (humid subtropical climate, Jiangxi province). These soil types represent a range of soil properties to be expected in Asian paddy fields. All upper‐most A horizons were analysed for their SOM composition by solid‐state ¹³C nuclear magnetic resonance (NMR) spectroscopy and for lignin‐derived phenols by the CuO oxidation method. The SOM composition was similar for all of the above named parent soil types (non‐paddy soils) and was also not affected by paddy soil management. A substantial proportion (up to 23%) of the total aryl‐carbon in some paddy and non‐paddy soils was found to originate from condensed aromatic‐carbon (e.g ., charcoal). This may be attributed to the burning of crop residues. On average, the proportion of lignin was low and made up 20% of the total SOM, and showed no differences between straw, particulate organic matter (POM), and the bulk soil material. The results from CuO oxidation are consistent with the data obtained from solid‐state ¹³C NMR spectroscopy. The extraction of lignin‐derived phenols revealed low VSC (vanillyl, syringyl, cinnamyl) values for all investigated soils in a range (4 to 12 g kg⁻¹ OC) that was typical for agricultural soils. In comparison to adjacent non‐paddy soils, the data do not provide evidence for a substantial accumulation of phenolic lignin‐derived structures in the paddy soils, even for those characterized by higher organic carbon (OC) contents (e.g ., Andosol‐ and Alisol (China)‐derived paddy soils). We conclude that the properties of the parent soil types are more important for the lignin content of the soils than the effect of paddy management itself.     

分子标记在动物源性商品材质鉴定中的应用

动物源性商品的材质鉴定,是识别商品掺杂掺假,防止疯牛病传播,保护野生动物的有效途径。笔者综述了目前通过分子标记手段检测动物源性成分的常用方法,对用RFLP、RAPD、AFLP和PCR鉴定技术及近些年兴起的基因条码等几种主要方法进行了评述和比较,并对分子标记在动物源性商品材质鉴定中应用前景进行了展望。     

Functional Marker Development and Effect Analysis of Grain Size Gene GW2 in Extreme Grain Size Germplasm in Rice

GW2 is an important gene that regulates grain width and weight. We used c DNA clone to obtain the sequences of GW2 from large- and small-grained rice varieties,TD70 and Kasalath,respectively. Then,we developed a d CAPS(derived cleaved amplified polymorphic sequence) marker on the basis of the sequence difference between functional and nonfunctional GW2 genes to analyze the genotypes and phenotypes of recombinant inbred lines. Results showed that the sequence of GW2TD70 had a single nucleotide deletion at site 316 that generates a termination codon. This codon terminated the GW2 protein in advance. By contrast,the sequence of GW2 Kasalath encoded an intact protein. A novel d CAPS marker was designed in accordance with a base A deletion at site 316 of the sequence. After the PCR product was digested by Apo I,TD70 showed 21 and 30 bp fragments,and Kasalath showed a 51 bp fragment. Up to 82 lines contained GW2TD70,and 158 lines contained GW2 Kasalath. The lines that contained TD70 alleles displayed substantial increases in width and 1000-grain weight. This result suggested that GW2 played a critical role in rice breeding.     

动物源性食品中猪源性成分检测

为探讨猪源性成分检测可行的方法,利用SYBR Green I Real time PCR对动物源性食品中猪源性成分进行测定。根据猪mtDNA保守序列设计特异性引物,对牛、羊、猪的动物源性食品进行扩增;克隆目的基因片段,并以此为标准品,优化反应条件和反应体系,提高灵敏度;反复检测不同样品,测试稳定性。结果表明SYBR Green I Real time PCR技术能够特异性的检测到动物源性食品中猪源性成分,引物特异性强、稳定性可靠,灵敏度达到1×10^-6 ng/μL,建立了动物源性食品中猪源性成分的快速、精准、经济、便捷的检测方法。     

Evaluation of semiochemical toxicity to houseflies and stable flies (Diptera: Muscidae)

BACKGROUND: The housefly, Musca domestica L., and stable fly, Stomoxys calcitrans (L.) are cosmopolitan pests of both farm and home environments. Houseflies have been shown to be resistant to a variety of insecticides, and new chemistries are slow to emerge on the market. Toxicities of selected semiochemicals with molecular structures indicative of insecticidal activity were determined against adults from an insecticide‐susceptible laboratory strain of houseflies. The three most active semiochemicals were also evaluated against recently colonized housefly and stable fly strains. RESULTS: Nineteen semiochemicals classified as aliphatic alcohols, terpenoids, ketones and carboxylic esters showed toxicity to houseflies and stable flies. Rosalva (LC₅₀ = 25.98 µg cm^?2) followed by geranyl acetone and citronellol (LC₅₀ = 49.97 and 50.02 µg cm^?2) were identified as the most toxic compounds to houseflies. Permethrin was up to 144‐fold more toxic than rosalva on the susceptible strain. However, it was only 35‐fold more toxic to the insecticide‐tolerant field strain. The compounds generated high toxicity to stable flies, with LC₅₀ values ranging from 16.30 to 40.41 µg cm^?2. CONCLUSION: Quantification of LC₅₀ values of rosalva, citronellol and geranyl acetone against susceptible housefly and field‐collected housefly and stable fly strains showed that semiochemicals could serve as potent insecticides for fly control programs. Copyright © 2010 Society of Chemical Industry