An experimental study of charcoal degradation in a boreal forest

Degradation rates of pyrogenic carbon (PyC) under natural environmental conditions are largely unknown. Here we present results from a field experiment monitoring the change in mass, C- and N concentrations of a variety of charcoal types in a Norwegian boreal forest over a period of 20 months. The charcoal types represent different feedstock tree species, production temperature regimes, and placements in the forest, i.e. above ground, in the humus layer or in contact with the mineral subsoil. The types of charcoal had different initial C concentrations mainly depending on their production temperature. Nevertheless, all types of charcoal at all placements in the forest showed an initial drop in their C concentrations, which subsequently rose back to reach near initial values in part of the charcoal types. In part of the charcoal types, N concentrations decreased throughout the experiment, exhibiting considerable variation among feedstock species, production temperature regime, and placements in the forest. C/N ratios rose especially in charcoal made from wood of Scots pine (Pinus sylvestris L.), and charcoal that had been stored in contact with the mineral subsoil showed the most rapid mass gain. Our results confirm the important influence of production temperature and feedstock type on the degradation of charcoal, but they also show that microbial activity and environmental conditions play significant roles in charcoal degradation and thus for the fate of pyrogenic carbon under natural conditions.     

猪急性腹泻综合征冠状病毒SYBR Green荧光定量PCR检测方法的建立及应用

为建立快速、灵敏且特异的检测猪急性腹泻综合征冠状病毒（swine acute diarrhea syndrome coronavirus,SADS-CoV）检测方法,本试验扩增SADS-CoV N基因保守区域将其克隆至pMD18-T载体。所构建的重组质粒pMD18-T-SADS-qN作为阳性质粒标准品,以其为模板建立一种SYBR Green荧光定量PCR检测方法。结果显示,所建立方法在3.31×10¹~3.31×10⁷拷贝·μL^-1模板量时,呈良好的线性关系,相关系数（R²）为0.997,斜率为-3.318。该方法特异性检测SADS-CoV;而猪流行性腹泻病毒（PEDV）、猪传染性胃肠炎病毒（TGEV）、猪德尔塔冠状病毒（PDCoV）和猪繁殖与呼吸综合征病毒（PRRSV）检测结果均为阴性。所构建的标准品检测灵敏度下限可以达到3.31×10¹拷贝·μL^-1,组内和组间变异系数均小于1%,表明其具有良好的灵敏性和重复性。用该方法检测SADS-CoV感染IPI-2I和IPEC-J2细胞后不同时间点和不同接毒剂量的复制情况,结果显示,SADS-CoV感染细胞后2 h病毒含量较低,在12~36 h病毒含量迅速增长,36 h后增长速度减缓且病毒含量维持在较高水平。分别用0、0.1、1 MOI SADS-CoV感染细胞结果显示病毒的mRAN转录水平呈现剂量依赖性增加,当MOI为1时,IPI-2I和IPEC-J2细胞病毒含量分别为10^6.7、10^5.3拷贝·mL^-1。进一步利用所建立的方法对经口服攻毒SADS-CoV仔猪的临床样本进行检测,结果发现病毒在空肠回肠含量较高,表明病毒主要定殖于空肠和回肠。综上表明,本研究建立SYBR Green荧光定量PCR检测方法能灵敏特异地检测SADS-CoV,为SADS-CoV的诊断和病毒相关基础研究提供可靠的检测手段。     

Cloning and Sequence Analysis of HA and NA Genes of One Strain of H6N6 Subtype Avian Influenza Virus Isolated from Guizhou Province

To investigate the epidemic situation of H6N6 subtype avian influenza virus (AIV) in Guizhou province,A/duck/Guizhou/013/2014 was isolated from Sansui duck in live poultry market of Guizhou in 2014,the hemagglutinin (HA) and neuraminidase (NA) genes of DK/GZ/14 were subjected to clone and sequence analysis.The results showed that HA gene had the highest nucleotide homologies (97.5%) with the duck-origin H6N6 subtype AIV isolated from Eastern China in 2009,and the strains of HA gene proteolytic cleavage sites was P-Q-I-E-T-R-G,which accordeol with the molecular characteristic of low pathogenic AIV (LPAIV).However,NA gene of A/duck/Guizhou/013/2014 had the highest nucleotide homologies (98.2%) with the duck-origin H6N6 subtype AIV isolated from Fujian in 2007.The phylogenetic tree showed that A/duck/Guizhou/013/2014 and Hunan strains located in the same branch,while three duck-origin H6N6 subtype AIV isolated from Guizhou in 2007 and A/duck/Guizhou/013/2014 located in the different branch for HA and NA genes in genetic evolution,which suggested that A/duck/Guizhou/013/2014 was far with the local H6N6 subtype.The results also clearly indicated that duck-origin H6N6 subtype AIV had genetic diversity in duck population in Guizhou.     

猪繁殖与呼吸综合征病毒分离株E11105 N基因的序列分析与原核表达

为研究PRRSV N蛋白的结构、功能以及N蛋白在病毒致病中的作用,以临床分离PRRSV毒株E11105为研究对象,采用Primer Premier 5.0设计一对特异性引物,经RT-PCR扩增出N基因片段,利用相关分子生物学软件对N基因序列进行分析;将N基因克隆连接到pColdⅠ原核表达载体上,经PCR、双酶切鉴定及序列测定后,得到重组质粒pColdⅠ-N,将pColdⅠ-N转入大肠埃希菌BL21(DE3)感受态细胞中,IPTG诱导表达后用SDS-PAGE蛋白电泳及Western blot验证分析。结果显示,分离株E11105N基因与北美洲型代表株VR-2332、欧洲型代表株Lelystad virus(LV)、中国2006年暴发的高致病性PRRSV代表株JXA1、中国代表株CH-1a的核苷酸序列同源性分别为93.3%、34.7%、99.2%、95.4%,氨基酸序列同源性分别为94.4%、15.3%、94.4%、99.2%;系统进化树显示,E11105株N基因与美洲型代表株VR-2332、中国高致病性JXA1毒株的亲缘关系较近;分离株E11105N基因所编码蛋白不存在跨膜区;二级结构主要以α-螺旋和无规则卷曲为主,分别占20.33%和63.41%;预测该蛋白可能存在5个较为明显的B细胞优势抗原表位。SDS-PAGE蛋白电泳结果表明,重组N蛋白主要存在于菌体沉淀中,分子质量约为16.7ku;Western blot结果显示,带His标签的重组表达蛋白能被His单克隆抗体识别,显色后条带约为16.7ku,与SDS-PAGE蛋白电泳的条带大小一致。     

丹参药渣栽培糙皮侧耳和毛头鬼伞

采用不同比例丹参(Salviae miltiorrhiza)药渣替代玉米芯对糙皮侧耳(Pleurotus ostreatus)、毛头鬼伞(Coprinus comatus)供试菌株进行栽培实验.经栽培收获两茬子实体,分别对不同配方两个菌种的菌丝长速、单位料重产量、生物学效率等指标进行统计分析.结果表明:在单位料重产量及生物学效率表现上,随培养料中所含丹参药渣比例增加而增加;在菌丝长速表现上则相反.经丹参药渣、玉米芯的碳氮比分析(28.5∶1;88.1∶1)得知,栽培料中随药渣含量的增加氮素含量相应提高(碳氮比55.27∶1～27.44∶1,氮含量为0.76％～2.43％),成为两个菌种产量增加的主要原因.     

氮肥配施生物炭和脲酶抑制剂对夏玉米-冬小麦产量及氮素利用的影响

于2019—2021年采用再裂区设计,设置氮肥、生物炭和脲酶抑制剂3个因素,主处理设5个氮水平：0、75、150、225 kg·hm^-2和300 kg·hm^-2,副处理设2个生物炭水平：0 t·hm^-2和7.5 t·hm^-2,副副处理设2个脲酶抑制剂水平：0%和2%,共20个处理,研究氮肥配施生物炭和脲酶抑制剂对夏玉米-冬小麦轮作体系作物产量和氮肥吸收利用的影响。结果表明,施用生物炭显著提高夏玉米和冬小麦产量、植株氮素吸收量、氮肥表观利用率、氮素收获指数以及夏玉米地上部生物量,较不施生物炭处理分别增加4.4%和2.9%、2.3%和3.0%、25.8%和13.5%、4.9%和6.1%、4.5%;氮肥单独配施生物炭可显著提高夏玉米和冬小麦产量、植株氮素吸收量和氮肥表观利用率,且氮肥和生物炭具有显著的交互效应。施用脲酶抑制剂显著增加夏玉米植株氮素吸收量和氮肥表观利用率,较不施脲酶抑制剂处理分别提高1.5%和3.0%;氮肥单独配施脲酶抑制剂可提高夏玉米植株氮素吸收量和氮肥表观利用率,但氮肥与脲酶抑制剂无显著...     

青海东部农区引进燕麦品种各器官C、N、P生态化学计量学特征变化研究

以4个引种燕麦(Avena sativa)为典型代表,对其不同生育时期根、茎、叶中的C、N、P含量及其化学计量学特征进行测定,探讨不同生育时期燕麦C、N、P元素含量及其化学计量比的变化规律,为燕麦饲草的科学收获提供理论依据。结果表明：燕麦全株C、N、P含量分别为322.30～333.97、17.42～75.62、2.74～5.42 mg·g^-1,燕麦根C、N、P含量分别为298.42～317.92、11.47～73.71、2.82～3.42 mg·g^-1,燕麦茎C、N、P含量分别为311.25～338.86、10.15～75.16、2.44～5.06 mg·g^-1,燕麦叶C、N、P含量分别为330.80～372.47、30.64～113.80、2.59～8.65 mg·g^-1;各器官间C、N、P含量表现为叶>茎>根。此外,燕麦各器官C、N、P含量的积累过程具有一定季节特征,C含量积累过程受生育时期影响较小,表现出较强的稳定性;而N和P含量的积累过程受生育时期影响较大,其在拔节期～抽穗期均...     

Detection of Ecballium elaterium in hedgerow olive orchards using a low-cost uncrewed aerial vehicle and open-source algorithms

BACKGROUND

Ecballium elaterium (common name: squirting cucumber) is an emerging weed problem in hedgerow or superintensive olive groves under no tillage. It colonizes the inter-row area infesting the natural or sown cover crops, and is considered a hard-to-control weed. Research in other woody crops has shown E. elaterium has a patchy distribution, which makes this weed susceptible to design a site-specific control strategy only addressed to E. elaterium patches. Therefore, the aim of this work was to develop a methodology based on the analysis of imagery acquired with an uncrewed aerial vehicle (UAV) to detect and map E. elaterium infestations in hedgerow olive orchards.

RESULTS

The study was conducted in two superintensive olive orchards, and the images were taken using a UAV equipped with an RGB sensor. Flights were conducted on two dates: in May, when there were various weeds infesting the orchard, and in September, when E. elaterium was the only infesting weed. UAV-orthomosaics in the first scenario were classified using random forest models, and the orthomosaics from September with E. elaterium as the only weed, were analyzed using an unsupervised algorithm. In both cases, the overall accuracies were over 0.85, and the producer's accuracies for E. elaterium ranged between 0.74 and 1.00.

CONCLUSION

These results allow the design of a site-specific and efficient herbicide control protocol which would represent a step forward in sustainable weed management. The development of these algorithms in free and open-source software fosters their application in small and medium farms. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

PA-X基因的长度变化对H3N2犬流感病毒复制能力和致病性的影响

H3N2犬流感病毒(canine influenza virus, CIV)已在中国多地的犬群中流行,是禽流感跨宿主感染并形成新分支的近期案例。研究表明,PA-X基因与甲型流感病毒适应新宿主的能力相关,且其长度能够影响甲型流感病毒的复制及致病能力。为了解PA-X基因的长度变化对H3N2 CIV复制能力及致病力的影响,本研究利用H3N2 CIV的8质粒操作系统,拯救了三株重组H3N2 CIV毒株：PA-X基因表达大小为232个氨基酸多肽的亲本病毒CIV＿PA-X＿232;对PA编码区第191、192位氨基酸的密码子进行改造,PA-X基因不表达蛋白的重组病毒CIV＿PA-X＿Knock;对PA+1编码区第232位氨基酸进行突变,PA-X基因表达大小为252个氨基酸多肽的重组病毒CIV＿PA-X＿252。通过比较3株重组病毒的聚合酶活性,在MDCK细胞中的复制效率及对小鼠致病性的差异,来评价表达不同长度的PA-X基因对H3N2 CIV的影响。结果显示,CIV＿PA-X＿252和CIV＿PA-X＿Knock的聚合酶活性显著(P<0.05)高于CIV＿PA-X＿232,且CIV＿PA-X＿...