红肉蜜柚 PDR 型转运蛋白基因的发掘及 CmPDR11-2 表达与耐草甘膦初步分析

基于红肉蜜柚 RNA-seq 数据库,筛选出 50 个 ABC 转运蛋白家族基因,其中包含 11 条 PDR 型基因。对11 条柚 PDR 基因进行命名和生物信息学分析。同源性分析结果表明：CmPDR11-2 编码的氨基酸序列与拟南芥中转运百草枯除草剂的 AtPDR11 基因同源性最高,达 69.25%,利用 RT-PCR 技术克隆得到 CmPDR11-2 的 ORF 序列。该序列长度为 4 371 bp,编码一个含有 1 456 个氨基酸的蛋白质,分子量 165.138 03 ku,该蛋白属于稳定的亲水性蛋白,无信号肽,具有 12 个跨膜结构,定位于细胞膜。实时荧光定量 PCR 结果表明,草甘膦除草剂胁迫处理条件下,1~15 d 处理组柚叶的 CmPDR11-2 基因相对表达量呈整体上升趋势,且均高于对照组,反应迅速且持久,这表明 CmPDR11-2 基因表达与红肉蜜柚耐草甘膦有关。     

Sole ulcers in Finnish dairy cattle

The Finnish Healthy Hooves project was set up to determine the frequency of, and risk factors for various hoof lesions in Finnish dairy herds. Data were collected in the years 2003 and 2004. A large dataset of over 74,000 cow-level observations recorded by hoof trimmers was merged with production data from the Finnish Agricultural Data Processing Centre Ltd. Ultimately, data from a single lactation from each of 16,792 cows in 703 herds were used for the analyses in this paper. Three-level hierarchical logistic models with hoof trimmer and farms (within hoof trimmer) as random effects were fit to data sets of tie stall (TS) and loose housing (LH) herds separately. The outcome of interest was the presence or absence of a sole ulcer in one or more legs of a cow during the lactation of interest.Cows examined once had a risk of sole ulcer 5.23% in tie stall herds and 7.58% in LH herds. As the number of examinations increased the odds of a diagnosis of sole ulcer increased substantially (2 and 3+ examinations had odds ratios (ORs) of 1.42 and 3.42 in TS herds and 2.77 and 6.89 in LH herds). Breed had a large effect on the risk of sole ulcer with Holsteins 2.89 times more likely to be affected than Ayrshires in TS herds and 2.94 times in LH herds. In TS herds, the presence of other hoof lesions such as haemorrhages (OR = 2.97), heel-horn erosions (OR = 2.10) and corkscrew claw (OR = 2.83) increased the risk of a sole ulcer developing. In LH herds, only haemorrhages (OR = 1.80) were a significant risk factor when parity was ≥2. In TS herds, use of mats (compared to hard flooring) significantly reduced the risk of sole ulcers (OR = 0.49). The effect of parity on the risk of sole ulcer was greatest when parity ≥4 but this effect was only significant in tie stalls (OR = 1.86).When analyses were restricted to cows with parity ≥2, similar results were obtained for the risk factors identified above. In addition, parity became highly significant in TS and LH (OR 2.31 and 2.23, respectively when parity was 4+). In TS herds, herd average milk production was significantly associated with a decrease risk of sole ulcer (OR = 1.28 per 1000 kg decrease) but there was no effect of production at the cow level (measured as deviation from the herd mean). No significant effects of production were observed in LH herds.     

Positional distribution of conjugated linoleic acid in triacylglycerol of Saccharomyces cerevisiae

Saccharomyces cerevisiae was cultivated in the presence of cis-9,trans-11 or trans-10,cis-12 isomers of free conjugated linoleic acid (CLA), and the effects of the isomers on the regioisomerisms of triacylglycerol (TAG) of the yeast were elucidated. Both isomers constituted about 34% of all fatty acids and increased drastically the number of different TAG species. Nearly all of the species contained CLA in at least one sn-position. In the most abundant species analyzed (20% of total species), the cis-9,trans-11 isomer appeared in combination with monounsaturated fatty acids (C16:1, C:18:1) whereas trans-10,cis-12 isomer was most frequently present with a medium chain fatty acid (C10:0 or C12:0) in the sn-2 position and C16:0 in one of the end positions (14% of total species). With either isomer, the amount of TAG species in which CLA encompassed all sn-positions was ca. 4%. Thus, S. cerevisiae can be used to produce edible single cell oil characterized by very heterogeneous distribution of CLA among the different TAG species.     

Microbially safe utilization of non-inactivated oats (Avena sativa L.) for production of conjugated linoleic acid

A microbially safe process for the enrichment of conjugated linoleic acid (CLA) in oats was developed. The process consists of hydrolysis of oat lipids by non-inactivated oat flour, followed by propionibacterium-catalyzed isomerization of the resulting free linoleic acid to CLA. The first stage was performed at water activity (a(w)) 0.7, where hydrolysis of triacylglycerols progressed efficiently without growth of the indigenous microflora of flour. Thereafter, the flour was incubated as a 5% (w/v) aqueous, sterilized slurry with Propionibacterium freudenreichii ssp. shermanii. The amount of CLA produced in 20 h was 11.5 mg/g dry matter corresponding to 116 mg/g lipids or 0.57 mg/mL slurry. The oat flour had also the capability to hydrolyze exogenous oils at a(w) 0.7. Sunflower oil, added to increase linoleic acid content in triacylglycerols 2.7-fold, was hydrolyzed rapidly. Isomerization of this oil-supplemented flour as a 5% slurry gave final CLA content of 22.3 mg/g dry matter after 50 h of fermentation, corresponding to 118 mg/g lipids or 1.14 mg/mL slurry. Storage stability of CLA in fermented oat slurries at 4 degrees C was good.     

不同生态条件下玉米单倍体自然加倍率及除草剂加倍效果

单倍体加倍率低成为玉米单倍体育种的限制性因素。为了提高玉米单倍体的加倍率,研究两种生态条件下单倍体的自然加倍率,比较甲基胺草磷(APM)和氟乐灵两种除草剂在不同浓度和处理方法下玉米单倍体的加倍效率。结果表明,海南试验点的单倍体自然加倍率要高于贵州贵阳试点。应用除草剂可以明显提高雅玉889和京糯208单倍体的加倍率,基础材料基因型对自然加倍率和除草剂加倍率都具有显著影响。APM和氟乐灵均是在浓度为80μmol·L~(-1)处理单倍体加倍率最高,APM处理的单倍体加倍率要高于氟乐灵,采用滴心法和浸种法处理的单倍体加倍率无明显差异。综上,如采用自然加倍,应在海南试验点种植单倍体;如采用除草剂加倍,应使用浓度为80μmol·L~(-1)的APM,采用滴心法或浸种法对雅玉889和京糯208单倍体加倍。     

Symptoms and yield reduction caused by Dickeya spp. strains isolated from potato and river water in Finland

Biochemical characterisation of Dickeya strains isolated from potato plants and river water samples in Finland showed that the majority of the strains were biovar 3. They thus resembled the strains recently isolated from potato in the Netherlands, Poland and Israel and form a new clade within the Dickeya genus. About half of the Finnish isolates resembling strains within this new clade were virulent and caused wilting, necrotic lesions and rotting of leaves and stems. Similar symptoms were caused by D. dianthicola strains isolated from one potato sample and from several river water samples. Frequently, the rotting caused by the Dickeya strains was visible in the upper parts of the stem, while the stem base was necrotic from the pith but hard and green on the outside, resulting in symptoms quite different from the blackleg caused by Pectobacterium atrosepticum. The presence of Dickeya in the symptomatic plants in the field assay was verified with a conventional PCR and with a real-time PCR test developed for the purpose. The virulent Dickeya strains reduced the yield of individual plants by up to 50% and caused rotting of the daughter tubers in the field and in storage. Management of Dickeya spp. in the potato production chain requires awareness of the symptoms and extensive knowledge about the epidemiology of the disease.     

自噬通路及其在顶复门原虫入侵发育中的作用

自噬(autophagy)是细胞通过降解自身大分子物质或破损细胞器等来维持胞内稳态的一种平衡机制.近年来在顶复门原虫与宿主细胞相互作用研究中发现,顶复门原虫不但可诱导宿主细胞产生自噬并启动天然免疫途径清除寄生虫,亦可进化出独特的机制来抵抗宿主细胞自噬甚至利用其为自身生长提供条件.不同种类顶复门原虫与宿主细胞互作方式不同...