Development and evaluation of enzyme-linked immunosorbent assay based on recombinant inorganic pyrophosphatase gene antigen for the detection of Mycoplasma suis antibodies

The recombinant ppa protein of Mycoplasma suis migrated to 21 kDa. Using this antigen, an ELISA system to detect the antibody against M. suis infection in swine was established. The rELISA demonstrated 98.5% specificities among negative samples and 96.9% sensitivity among positive samples with M. suis infection. A comparison of this ELISA system with an indirect hemagglutination assay (IHA) test using 132 swine samples revealed that the positive rate was 34.0% in ELISA and 28.0% in IHA. Compared with IHA, the present rELISA system using recombinant ppa antigen significantly improves the specificity, sensitivity, and stability for serodiagnosis of M. suis infection in swine.     

慈溪杨梅硒含量检测结果

检测了慈溪杨梅126批次,平均含硒量0.018mg/kg,其它县市杨梅159批,平均含硒量0.018mg/kg。慈溪杨梅中,硒含量≥0.01mg/kg有118批,占93.7%,其它县市杨梅中只占44.0%;硒含量≥0.015mg/kg的样品占66.6%,而其它县市只占16.4%。结果表明,慈溪杨梅硒含量显著高于其它县市杨梅硒含量,达到富硒食品标准,有利于进行富硒杨梅产业化开发。     

以超滤技术浓缩猪细小病毒含毒细胞液的试验

在研制猪细小病毒灭活疫苗时,应用了超滤浓缩技术,提高了合毒细胞培养液中的抗原含量。为了保证浓缩的流量,减少对滤膜的污染,对含毒细胞培养液作了预处理一离心及微滤,以便除去细胞培养液中的细胞碎片、蛋白质等大分子物质及固形微粒。超滤时选用50000Da滤膜,在20psig压力下,经过5倍浓缩的PPV细胞培养液,血凝滴度提高2个滴度以上。病毒含量测定表明,TCID50／0．2mL由107左右升至109以上,以其配制疫苗,能显著地提高疫苗的免疫原性。超滤技术具有易于操作、高效、分离精度高、没有二次污染等优点,可以根据需要选择不同的浓缩浓度,对保证疫苗的质量具有重要作用。     

利用脉搏波参数间接测定大鼠动脉血压的一种方法

通过提取动脉脉搏波特征参数,建立了间接测定大鼠动脉血压的多元回归方程。结果表明:脉搏波周期、K值、脉搏波波图面积等参数与动脉收缩压有较好的相关性,与颈动脉有创血压测定法数值比较,有较小差异(P>0. 05),表明所筛选的脉搏波特征参数能准确地反映动脉的每搏收缩压值,但与舒张压相关性较差。该方法简便、准确、稳定性好,便于长期动态观察。     

CIMMYT 145份小麦种质资源的鉴定及杂交利用

为了拓宽和丰富小麦种质资源遗传多样性,提高小麦产量和品质,在大田对国外引进的145份小麦种质资源进行了农艺性状和品质性状的鉴定和评价。结果表明,这些材料基本属弱春性类型。在山西南部麦区,可推迟播期于10月下旬种植,作为育种材料利用。主要农艺性状的单株穗数、穗粒数、千粒重和产量变异系数分别为15.7%、16.03%、12.23%和23.96%,多数材料籽粒综合品质较好,尤其面筋品质好,筋力强。这些材料的农艺性状和品质性状具有丰富的遗传多样性。株高和千粒重与产量的相关系数最大,分别为0.5032和0.4178,达极显著水平,是提高产量的关键因素。综合3年试验结果,筛选出产量超过3750 kg/hm2有32份,鉴选出8个组合的相应强筋力品系和35个综合性状表现较优异品系,其突出优异性状表现植株穗大,小穗结实好,穗粒多,可作为小麦育种的重点种质材料利用。通过播期调节花期,利用CIMMYT材料合理杂交配组,已选育至F3代、BC2F1代和BC1F1代,有望育成优质大穗丰产抗旱创新材料及新品系。     

慈溪市乡土树种资源调查研究(Ⅱ)——蓝果和黑果类绿化观赏树种资源与开发利用

对浙江省慈溪市乡土树种进行了调查整理,得到65种(含变种)蓝果和黑果类绿化观赏树种名录,隶属25科39属,其中慈溪新记录16种,隶属9科13属。分析了树种的地理分布、果实颜色、果熟期和果实观赏性等,并以园林观赏、生态防护、滨海盐土造林、断面边坡覆绿、水湿地绿化和其它用途的分类方式,对各树种的用途进行归类研究。最后列举了4种树种的性状和利用价值。     

Under drought conditions NaCl improves the nutritional status of the xerophyte Zygophyllum xanthoxylum but not of the glycophyte Arabidopsis thaliana

Zygophyllum xanthoxylum is a salt‐accumulating xerophytic species with excellent adaptability to adverse environments. Previous studies demonstrated that Z. xanthoxylum absorbs a great quantity of Na⁺ as an osmoregulatory substance under arid conditions. To investigate the nutritional status of Z. xanthoxylum in comparison with a typical glycophyte, Arabidopsis thaliana, seedlings were exposed to NaCl (50 mM for Z. xanthoxylum and 5 mM for A. thaliana), osmotic stress (–0.5 MPa), and osmotic stress combined with the NaCl treatment. Compared to the control, NaCl treatment or osmotic stress significantly increased Na⁺ concentration in leaves and roots of Z. xanthoxylum, but not of A. thaliana. Under osmotic stress, the addition of NaCl significantly increased Na⁺ concentration in leaves and roots of Z. xanthoxylum, resulting in improved biomass and tissue water content. However, such changes were not observed in A. thaliana. Compared to the control, K⁺ concentrations in leaves and roots remained unchanged in Z. xanthoxylum when exposed to osmotic stress, with or without additional 50 mM NaCl. In contrast, significant reductions in shoot K⁺ concentrations of A. thaliana were observed under osmotic stress alone or when combined with 5 mM NaCl. Moreover, NaCl alone or when combined with osmotic stress enhanced the accumulation of N, P, Fe, Si, Ca²⁺, and Mg²⁺ in Z. xanthoxylum, but did not cause such nutritional changes in A. thaliana. Compared to the glycophyte A. thaliana, Z. xanthoxylum could accumulate Na⁺ and maintain the stability of nutritional status at a relatively constant level to cope with drought stress.     

Chemical response of hardwood oligosaccharides as a statistical function of isolation protocol

Hardwoods contain a substantial amount of hemicellulose-type oligosaccharides, the chemical structures of which are typically categorized in the xylan saccharide class. The efficient and selective isolation of these hemicelluloses is regarded as one of the most critical obstacles to overcome for their eventual biomaterial and bioenergy utilization. Therefore, the objective of the current work was to perform a fundamental exploration of the function of extraction pH, temperature, and time on the final chemical properties of the extracted hemicelluloses. The extraction chemistries employed varied pH and showed that acidic conditions provided a higher extractive yield versus alkaline conditions. An alkaline environment gave higher yields than an acidic environment and also resulted in much higher lignin removal from wood, especially at high temperature. In general, control of the pH chemistry leads to a change in the carboxylic acid groups present in the extracts. When the extraction pH changed from acidic to alkaline, the total carboxylic acid group content in the hemicelluloses removed significantly increased due to more acetic acid group hydrolysis and increased lignin degradation.     

近自然经营对马尾松林不同发展阶段竞争关系的影响

以实施近自然经营措施8a后的幼龄林、中龄林、近熟林3个不同发展阶段的马尾松(Pinus massoni-ana Lamb.)林为研究对象,根据Hegyi竞争指数,探讨近自然经营对马尾松林竞争关系的影响.结果表明:调查林分中马尾松是数量最多的树种且占据绝对优势地位;实施近自然经营措施的林分中马尾松的优势度较对应的对照林分明显降低,主要伴生树种杉木(Cunninghamia lanceolata(Lamb.)Hook)、枫香(Liquidambar formosana Hance)、白栎(Quercus fabri Hance)、麻栎(Quercus acutissima Carruth)等优势度明显提升.随着径级的增大,马尾松林分整体竞争强度逐渐减小,经营林分更为明显.林木的竞争强度与胸径均符合幂函数关系,竞争强度随着个体的增大而减小;经营林分的趋势线比相应对照林分更平缓,更易达到稳定状态.不同发展阶段各树种的竞争强度均表现为经营林分马尾松的竞争强度与相应对照林分相比明显降低;伴生树种的竞争强度明显提升.综上,近自然经营能够有效改善马尾松林竞争关系,加速林分达到稳定状态.