Faecal shedding detected earlier than immune responses in goats naturally infected with Mycobacterium avium subsp. paratuberculosis

Paratuberculosis was diagnosed in a goat herd that participated in a sanitation program against Mycobacterium avium subsp. paratuberculosis. The aim of this study was to characterise the development of gamma interferon (IFN-γ) and antibody responses as well as the occurrence of faecal shedding. Faecal culture appeared surprisingly sensitive as about 18% and 40% of the goats were positive at 9 and 15-17 months of age, respectively, and shedding was often seen prior to peripheral immune responses. Peripheral IFN-γ responses were not related to protection as clinical and high shedding goats often had high responses. An IFN-γ response usually preceded a humoral response. However, positive antibody titers could sometimes be seen simultaneously with, and even prior to, IFN-γ responses. In conclusion, faecal culture appeared as sensitive as IFN-γ testing. Furthermore, the antibody ELISA and the IFN-γ assay may perform equally well in an infected herd if surveillance is conducted annually.     

稻渔综合种养的科学范式

探讨不同养殖模式下金背鲤 (Cyprinus carpio var. Jinbei) 肠道菌群和鱼肉风味品质差异,对金背鲤的繁殖优化具有重要意义。采用高通量测序技术对稻田放养和池塘养殖模式下金背鲤的肠道微生物进行测序,利用液相色谱和顶空固相微萃取-气相色谱-离子迁移谱联用 (HS-SPME-GC-IMS) 技术测定其滋味物质、挥发性风味化合物,结合感觉阈值计算滋味活性值和相对气味活度值。结果显示：两种养殖模式的金背鲤肠道细菌群落结构差异显著,稻田放养 (FGF) 组以弧菌 (Vibrio)、拟杆菌 (Bacteroides)、交替单胞菌 (Alteromonadales)、希瓦氏菌 (Shewanella)、嗜冷假单胞菌 (Pseudomonas psychrophile) 和Brevinema属为主,池塘养殖 (FGP) 组以莫拉克斯氏菌 (Moraxella) 和克雷伯菌属 (Klebsiella) 为主;FGF组中鲜味肌苷酸含量及其滋味活性值 (1.676 g·kg⁻¹, 6.705) 远高于FGP组 (0.246 g·kg⁻¹, 0.985),FGF组鲜味氨基酸和甜味氨基酸含量 (0.143和2.052 g·kg⁻¹) 高于FGP组 (0.109和2.001 g·kg⁻¹),而其苦味氨基酸 (3.193 g·kg⁻¹) 却低于FGP组 (3.836 g·kg⁻¹);金背鲤的挥发性化合物组分复杂,其关键气味化合物 (ROAV≥1) 和对整体风味有修饰作用的化合物 (0.1≤ROAV<1) 的种类存在差异。菌属与风味物质的相关性分析显示弧菌属、拟杆菌属、克雷伯菌属和摩根菌属 (Morganella) 与风味物质呈显著相关 (0.01≤P<0.05 & 0.001≤P<0.01 & P<0.001)。研究表明,养殖模式影响了金背鲤的肠道微生物,并间接影响了其风味品质。     

茉莉酸甲酯对葡萄植株不定根发育的影响

利用不同浓度的茉莉酸甲酯（MeJA）对葡萄组培植株进行处理,进而分析其生理及基因表达变化,结果表明MeJA能抑制植株不定根的分化和伸长,诱导根、茎、叶组织中的脱落酸（ABA）含量升高,但降低赤霉素（GA）、生长素（IAA）和细胞分裂素（ZR）的含量,且影响叶片中叶绿素代谢导致褪绿黄化。MeJA能诱导植物体内茉莉酸合成代谢基因表达进而提高内源茉莉酸的含量,诱导ABA合成代谢和信号路径中的基因表达,但是会抑制生长素、赤霉素、细胞分裂素、油菜素内酯合成代谢基因的表达,抑制了与根发育和延伸相关基因VvXET、VvEXPB2、VvEXPA7和VvWUS的表达,进而抑制不定根的发生,导致植物发育缓慢。因此,MeJA通过影响其他激素的合成代谢来调控它们在植物中的含量,导致内源激素不平衡影响植株发育,并调控植株根的发育状态,在不定根发育方面起负向调控作用。     

道路景观设计方法探讨

提出对道路景观的规划、调查、定位等系统分析,从而在道路的形态、周边环境的借景及路域生态系统的景观绿化等方面,探讨了道路景观设计的方法。     

瓜类蔬菜组织培养与遗传转化研究进展

概述了瓜类蔬菜组织培养过程中的主要影响因素—基因型、外植体类型,部位与生理状态、培养基、生长调节物质、碳源及其他添加物质对植株再生的影响,以及根癌农杆菌介导的瓜类蔬菜遗传转化的影响因素与研究进展。     

Somaclonal variation and improvement in chilling tolerance in rice: changes in chilling-induced electrolyte leakage

Excised leaves of four rice varieties, ‘Facagro 57’, ‘Facagro 76’, ‘Kirundo 3’, ‘Kirundo 9’, were chilled for six days at 10/5°C day/night, along with 11 somaclonal families arising from three of these varieties, which had been selected over four generations for improved chilling tolerance. At the end of the chilling treatment, electrolyte leakage from leaf pieces was followed for 12 h and compared with an unchilled control. With unchilled leaves, no varietal differences nor a rise in leakage over time were observed. Chilling induced higher leakages in all varieties, except in ‘Kirundo 3’ at the time of first measurement, and a continuous rise over time was found in all varieties. Varietal differences were detected, ‘Kirundo 3’ being the least affected, followed by ‘Kirundo 9’ and ‘Facagro 76’, and finally ‘Facagro 57’, which coincides with their ranking for chilling tolerance established through chilling survival tests. The leakages were generally lower in the somaclonal families than in the variety they originated from in ‘Kirundo 9’ and ‘Facagro 76’, while the opposite was observed in ‘Kirundo 3’. The significance and usefulness of electrolyte leakage measurement for chilling tolerance screening, and the potentials of somaclonal variation for chilling tolerance improvement are discussed.     

瞿麦组织培养和快速繁殖

以瞿麦种子获得的无菌苗和无菌苗的茎段作为外植体,以MS为基本培养基,添加不同浓度的激素,研究瞿麦组织培养的最佳条件.结果表明:最适宜无菌苗丛生芽诱导的培养基为MS+6-BA 1.0mg/L+NAA 0.4 mg/L;无菌苗茎段丛生芽诱导中,在MS+6-BA 0.2 mg/L+KT0.4 mg/L+NAA 0.1 mg/L有利于瞿麦的快速繁殖;最适宜的生根培养基为1/2MS+NAA0.1 mg/L.为提高试管苗增殖率及避免玻璃化现象的发生,最佳继代周期28 d,最适宜光照3 000 lx.     

小菜蛾高致病力绿僵菌的筛选、鉴定及培养特性研究

为开发蔬菜害虫小菜蛾Plutella xylostella的高致病力真菌生物农药,以3龄小菜蛾幼虫为供试虫源,测定了25株虫生真菌菌株对小菜蛾的致病力,从中筛选出1株对小菜蛾幼虫有较高致病力的菌株CQM125。生测结果显示,在20℃、1.0×108孢子mL 1菌株CQM125菌液处理小菜蛾幼虫的LT50为3.97 d;25℃、5.0×107孢子mL 1菌液的LT50为2.44 d;在25℃下,第7 d的LC50为2.31×104孢子mL 1;接种处理后,20℃、8 d的小菜蛾死亡率为84.22%,对小菜蛾表现出良好的控制效果。依据菌株的形态特征、培养性状和rDNA ITS序列分析将菌株CQM125鉴定为金龟子绿僵菌Metarhizium anisopliae。对该菌株的培养基和培养条件进行了优化,优化后的产孢培养基为PPDA,其中葡萄糖2%,蛋白胨0.5%;最适产孢温度30℃,最适产孢pH值为6.0;最适光照条件为前6 d黑暗,后8 d光照。     

木立芦荟的组织培养及快速繁殖

以木立芦荟的叶片、叶鞘和带腋芽的茎段为外植体进行试管培养,结果表明,叶鞘和茎段可诱导形成愈伤组织,腋芽直接萌生。经试验筛选出各培养阶段最适宜的培养基为：（1）愈伤组织诱导,MS＋6－BA2。5mg/L NAA0.15mg/L;（2）腋芽萌生,MS＋6－BA2.0mg/L NAA0.15mg/L;（3）丛生芽分化及继代,MS＋6-BA2.0mg/L NAA0.10mg/L;(4)生根,MS 6-BA0.3-0.5mg/L IBA0.2mg/L＋活性羰0.5%。     

蒙古栎秋播种育苗技术的研究

自１９９３年起对本局大趟子苗圃进行了蒙古栎秋播育苗试验,并对蒙古栎从采种、种子调制、田间管理及起苗、留床、造林等环节上形成了一套完整的科学育苗方法,避免了春播育苗种子储藏和鼠害等一系列不利问题,研究探索了最佳播种量和最佳经营密度。