大挖深菊芋收获机设计与试验

针对菊芋收获作业要求,研制了大挖深菊芋收获机。该机由外倾整体式条形挖掘铲、两级抖动链式输送分离器及机架、地轮构成,可一次性完成菊芋挖掘、芋土分离、输送、铺放。田间试验表明：该机能在250~500 mm挖掘深度,初霜冻、菊芋团块根系发达地块,克服冻土块、砾石卡塞导致的土壤拥堵,实现持续稳定作业; 对菊芋收获质量好,芋土分离效果良好,损失率、伤薯率、含杂率分别小于1.75%、4.8%、4.5%, 满足菊芋收获作业要求。     

Establishment and verification of insulin resistance model in mouse skeletal muscle cells

AIM:To establish a stable and repeatable insulin resistance model of skeletal muscle cells in vitro, so as to promote the exploration of the pathological mechanism of insulin resistance and the development and screening of related drugs. METHODS:C2C12 mouse myoblasts were used to induce differentiation in normal differentiation medium and differentiation medium containing glucose at 40 and 60 mmol/L, respectively. The effects of glucose at different concentrations on cell convergence, fusion and formation of multinucleated myotubes were observed under phase contrast microscope every day. After 1, 3, 5 and 7 d of differentiation, 2-NBDG assay was used to detect the effects of different interventions on C2C12 basal glucose uptake and insulin-stimulated glucose uptake. The effects of different interventions on the protein expression of glucose transporter 4 (GLUT4) after 5 d and 7 d of differentiation were determined by Western blot. The effects of different interventions on the distribution of GLUT4 protein after 5 d of differentiation were detected by immunofluorescence staining. RESULTS:After treated with glucose at 60 mmol/L, the morphological observation showed that high glucose treatment significantly inhibited the growth and differentiation of C2C12 cells after 3 d. High glucose treatment significantly inhibited basal glucose uptake and insulin-stimulated glucose uptake of the C2C12 cells after 5 d and 7 d (P<0.01). No difference between insulin-stimulated GLUT4 expression and basal GLUT4 expression after 5 d and 7 d of high glucose treatment was observed (P>0.05), but there was significant difference between control group and 60 mmol/L group (P<0.05) determined by Western blot. Immunofluorescence staining observation showed that the distribution of GLUT4 protein in the C2C12 cell membrane was significantly decreased after 5 d of high glucose treatment (P<0.01). Glucose treatment (40 mmol/L) also played a role to some extent, but the effect was not as obvious and stable as 60 mmol/L glucose. CONCLUSION:A stable insulin resistance model of mouse skeletal muscle cells in vitro was successfully established by high glucose stimulation. The treatment of glucose at 60 mmol/L for 5 d was the best. Morphological observation and detection of basic and insulin-stimulated glucose uptake and GLUT4 protein expression and distribution evaluates the insulin resistance level of skeletal muscle cells in vitro.     

基于SNP标记的糯玉米种质资源遗传多样性分析

为了提高糯玉米种质资源的利用效率,挖掘优异糯玉米种质资源、改良糯玉米品种,利用(Single nucleotide polymorphism,SNP)芯片技术对44份不同来源的糯玉米自交系和5份分别代表中国玉米5大类群的普通玉米自交系进行全基因组扫描。结果表明,34 257个SNP标记在49份玉米自交系中的多态性信息含量(polymorphism information content,PIC)为0.02～0.56,平均含量为0.32;最小等位基因频率(minor allele frequency,MAF)≥0.03。49份玉米自交系间的状态一致性(identity-by-state,IBS)变幅为0.59～0.99,平均为0.68。基于IBS利用Neighbor-joining(NJ)聚类分析方法,将49份自交系划分为5个类群,分别包含19份、9份、4份、9份和3份材料,其中系谱来源不清晰的糯玉米自交系被划分至不同类群,明确了它们的亲缘关系。     

桃乙烯应答因子PpERF1a的克隆与功能分析

以‘丰光’油桃嫩梢组织为试材,克隆了1个ERF家族基因并命名为PpERF1a（ppa018178m）。该基因全长为600 bp,编码199个氨基酸,含有1 个典型的AP2 结构域。亚细胞定位结果显示PpERF1a定位于细胞膜和细胞核。在拟南芥中超量表达PpERF1a,共获得15个阳性转基因株系。与对照相比,转基因植株出现发育不良的表型,其中6株持续长出莲座叶,但不抽薹;6株能够抽薹开花,但不结实且生长势明显弱于对照;3株能够开花结实,但种子产量极低。这些结果表明PpERF1a在转基因拟南芥中具有调控生长发育的功能,为后期在桃中开展PpERF1a的功能研究提供了有益的启示。     

A PCR diagnostic assay for rapid detection of plant pathogenic pseudomonads

Molecular detection of phytopathogens is increasingly being applied to identify regulated organisms at the border in many parts of the world. However, even with molecular tests, complete phenotyping and identification of a strain is often time consuming and sometimes inconclusive. In this study, a leaf-based pathogenicity test was used to separate pseudomonads into two groups, Group A containing pathogens, and Group B containing saprotrophs. Comparative genomics of 56 pseudomonad genomes from different plant hosts (including 29 strains from kiwifruit) agreed with kiwifruit pathogenicity test results, placing pathogens into Group A and saprotrophs into Group B. Sixteen loci were found unique to Group A. A PCR assay was developed for amplification of one of these loci, the trehalose phosphatase gene. The generation of this 655 bp amplicon was associated with production of water-soaked lesions on inoculated kiwifruit leaves by pseudomonads in Group A. This test was validated for further strains from all seven pathogenic Pseudomonas phylogroups, non-pathogenic pseudomonads, and other bacterial genera. The sensitivity of the PCR was comparable to the limit of recovery of pseudomonads by culturing. This simple PCR assay could be used as part of a testing pipeline at the border and for general surveillance for screening plants with and without symptoms, offering the potential to detect uncharacterized pseudomonads that may pose a biosecurity risk. The method was shown to be able to rapidly identify pathogens cultured from plant material with symptoms, or, more importantly, to detect pathogens directly from plant tissue.     

有色膜覆盖对春大白菜光合特性及产量的影响

以早春拱棚栽培‘菊锦’大白菜为试材,无色棚膜为对照,研究有色棚膜对春大白菜光合特性、生长量及产量的影响。结果表明,在相同光量子通量密度(PFD)下,紫膜和红膜处理的气温较高,空气湿度较低;蓝膜和绿膜的气温较低,而空气湿度略高。各处理大白菜叶片光合速率(P_n)日变化呈单峰曲线型,紫膜和红膜的P_n显著大于对照,而蓝膜和绿膜与对照差异不显著;早春棚栽大白菜的光饱和点(LSP)为1133.4~1217.5μmol·m~(-2)·s~(-1),紫膜和红膜的明显高于对照,蓝膜和绿膜与对照无显著差异。各处理大白菜的光补偿点(LCP)、表观量子效率(AQY)、CO_2补偿点和饱和点差异不大,但紫膜的羧化效率(CE)显著高于对照,绿膜的明显低于对照。晴天中午红膜和紫膜的光呼吸速率(P_r)低于对照,光能利用率(LUE)高于对照。核酮糖–1,5–二磷酸羧化酶(RuBPCase)、果糖–1,6–二磷酸酶(FBPase)、景天庚酮糖–1,7–二磷酸酶(SBPase)和转酮醇酶(TK)的活性多以紫膜和红膜较高,绿膜较低。与对照相比,紫膜和红膜的生长量较大,而绿膜的较小,蓝膜与对照差异不显著。紫膜和红膜的经济学产量分别比对照高15.1%和7.8%,而蓝膜和绿膜的比对照低6.4%和15.5%。可见,紫膜和红膜可提高大白菜叶片的光能利用效率,增强光合碳同化能力,从而促进植株生长,产量明显提高;绿膜处理的结果相反。     

华山松腐烂病及防治研究

在查清华山松腐烂的病原,首次找到其有性型,在初步掌握病害的侵染循环、危害情况和部分防治试验的基础上,提出了相应的防治措施。     

Sorghum Bran as a Potential Source of Kafirin

Sorghum bran, a coproduct of sorghum dry milling, could be a source of protein for industrial applications. Condensed tannin‐free red and white sorghum samples were decorticated by abrasion until ≈10 or 25% grain by weight was removed. Kafirin was then extracted from the milling fractions using an aqueous ethanol based solvent system. The brans were darker and considerably higher in protein and fat compared with the whole grain flours and decorticated grain flours, with the 25% bran having higher protein than the 10% bran. This is due to increased contamination of the bran with protein‐dense, corneous endosperm. The protein extracted from all the milling fractions, including the brans, was pure kafirin. However, the yield of kafirin from the brans (15.9–26.7% of total protein present) was somewhat lower than that from whole grain and decorticated grain flours (45.0–57.9% of total protein present), due to the fact that kafirin is located solely in the endosperm. Also, the kafirin from bran was more contaminated with fat, polyphenols, and other substances, and more highly colored, particularly the kafirin from red sorghum. Thus, sorghum bran could be used as a source of kafirin but further purification steps may be necessary.