黄土高原根瘤菌数值分类及DNA-DNA杂交

黄土高原位于我国内陆,气候比较干旱,生长的植被较少,水土流失严重,而有些豆科植物如锦鸡儿(Caragana sinica)、苦豆子(Sophora alopecuroides)、甘草(Glycyrrhiza uralensis)、苦马豆(Swainsoniasalsula)、洋槐(Robinia pseudoacacia)等却能很好生长.这些豆科植物的生长,在防风固沙、保持水土、绿化环境、作为饲用牧草等方面起着很重要的作用.但人们对于黄土高原野生豆科植物根瘤菌的研究尚很少.为此,作者在地处黄土高原的陕西、宁夏及甘肃的部分地区进行了广泛的根瘤菌资源调查.在此基础上,对分离的部分菌株进行了数值分类和DNA同源性分析.     

New Species of Meconopsis(Papaveraceae) from Laojun Shan and Yao Shan,Northern Yunnan,China

Two new species,Meconopsis muscicola and M.yaoshanensis(Papaveraceae),are described and characterized.Differences separating them from similar species are discussed and photos showing their diagnostic features are provided.     

厄贝沙坦对人脐静脉内皮细胞株EA.hy926增殖、凋亡、VEGF mRNA表达的影响

目的:应用不同浓度厄贝沙坦对人脐静脉内皮细胞株EA.hy 926的增殖、凋亡生物学效应及血管发生主要基因VEGFmRNA的表达进行体外研究,探讨厄贝沙坦对内皮细胞的血管生成效应。方法:各种浓度厄贝沙坦对人脐静脉内皮细胞株EA.hy926共同孵育24 h。细胞增殖采用CCK8法分析,Annexin V/PI双染法检测细胞凋亡。RT-PCR验证VEGFmRNA的表达。结果:厄贝沙坦各浓度干预组细胞形态无明显变化,CCK8结果提示厄贝沙坦各干预组相比对照组细胞增殖活力增高(P<0.05),呈浓度非依赖性。流式细胞仪分析厄贝沙坦各浓度干预组细胞无明显凋亡。RT-PCR发现厄贝沙坦1×10-4,1×10-5,1×10-6mol/L浓度组VEGFmRNA表达增高(P<0.05)。结论:厄贝沙坦促进EA.hy926细胞株细胞增殖,上调VEGFmRNA的表达。这提示除了降压效应,血管紧张素受体拮抗剂在缺血性心脏病如慢性心力衰竭治疗中具有一定作用。     

Phenotyping for Abiotic Stress Tolerance in Maize

The ability to quickly develop germplasm having tolerance to several complex polygenic inherited abiotic and biotic stresses combined is critical to the resilience of cropping systems in the face of climate change.Molecular breeding offers the tools to accelerate cereal breeding;however,suitable phenotyping proto-cols are essential to ensure that the much-anticipated benefits of molecular breeding can be realized.To facilitate the full potential of molecular tools,greater emphasis needs to be given to reducing the within-experimental site variability,application of stress and characterization of the environment and appropriate phenotyping tools.Yield is a function of many processes throughout the plantcycle,and thus integrative traits that encompass crop performance over time or organization level(i.e.canopy level) will provide a better alternative to instantaneous measurements which provide only a snapshot of a given plant process.Many new phenotyping tools based on remote sensing are now available including non-destructive measurements of growth-related parameters based on spectral reflectance and infrared thermometry to estimate plant water status.Here we describe key field phenotyping protocols for maize with emphasis on tolerance to drought and low nitrogen.     

Soybean ferritin: isolation, characterization, and free radical generation

The main aim of this work was to assess the multi-task role of ferritin(Ft)in the oxidative metabolism of soybean(Glycine max).Soybean seeds incubated for 24 h yielded 41 ± 5 μg Ft/g fresh weight.The rate of in vitro incorporation of iron(Fe)into Ft was tested by supplementing the reaction medium with physiological Fe chelators.The control rate,observed in the presence of 100 μM Fe,was not significantly different from the values observed in the presence of 100 μM Fe-his.However,it was significantly higher in the presence of 100 μM Fe-citrate(approximately 4.5-fold)or of 100 μM Fe-ATP(approximately 14-fold).Moreover,a substantial decrease in the Trp-dependent fluorescence of the Ft protein was determined during Fe uptake from Fe-citrate,as compared with the control.On the other hand,Ft addition to homogenates from soybean embryonic axes reduced endogenously generated ascorbyl radical,according to its capacity for Fe uptake.The data presented here suggest that Ft could be involved in the generation of free radicals,such as hydroxyl radical,by Fe-catalyzed reactions.Moreover,the scavenging of these radicals by Ft itself could then lead to protein damage.However,Ft could also prevent cellular damage by the uptake of catalytically active Fe.     

The Basal Level Ethylene Response is Important to the Wall and Endomembrane Structure in the Hypocotyl Cells of Etiolated Arabidopsis Seedlings

The sub-cellular events that occur during the ethylene-modulated cell elongation were characterized by examining the ultra-structure of etiolated Arabidopsis seedling hypocotyl cells. Preventing the basal level ethylene response facilitated cell elongation, and the cells exhibited wall loosening and separation phenotype. Nearby the wall separation sites were frequently associated with an increase in the cortical rough endoplasmic reticulum (rER) membranes, the presence of paramural bodies, and the circular Golgi formation. The cortical rER proliferation and circular Golgi phenotype were reverted by the protein biosynthesis inhibitor cycloheximide. The cortical rER membranes were longer when the ethylene response was prevented and shortened with elevated ethylene responses. Proteomic changes between wild type and the ethylene-insensitive mutant ethylene insensitive2 (ein2) seedling hypocotyls indicated that distinct subsets of proteins involving endomembrane trafficking, remodeling, and wall modifications were differentially expressed. FM4-64 staining supported the proteomic changes, which indicated reduced endocytosis activity with alleviation of the ethylene response. The basal level ethylene response has an important role in endomembrane trafficking, biological materials transport and maintenance of the endomembrane organization. It is possible that endomembrane alterations may partly associate with the wall modifications, though the biological significance of the alterations should be addressed in future studies.     

Synthesis and degradation of the major allergens in developing and germinating soybean seed

Gly m Bd 28K,Gly m Bd 30K and Gly m Bd 60K are the major soybean(Glycine max(L.)Merr.)allergens limiting the consumption of a good protein source for sensitive individuals.However,little is known about their temporal-spatial expression during seed development and upon germination.The present data shows that soy allergens accumulated in both the embryonic axes and cotyledon,but expression patterns differed depending on the specific allergen.Allergens accumulated sooner and to a greater level in cotyledons than in embryonic axes.Gly m Bd 28 began at 14 d after flowering,7 to 14 d earlier than Gly m Bd 30K and Gly m Bd 60K.Comparatively,their degradation was faster and more profound in embryonic axes than in cotyledons.Gly m Bd 60K began to decline at 36 h after imbibition and remained detectable up to 108 h in cotyledons.In contrast,the Glym Bd 60K protein was reduced at 24 h,and eventually disappeared at 96 h.In cotyledons Gly m Bd 28K first declined at 24 h,then increased from 36 h to 48 h,followed by its large reduction at 72 h after seed germination.These findings provide useful information on soy allergen biosynthesis and will help move forward towards developing a hypoallergenic soybean for safer food.     

Interactions Between Temperature and Sugars in the Regulation of Leaf Senescence in the Perennial Herb Arabis alpina L.

Annual plants usually flower and set seed once before senescence results in the death of the whole plant (monocarpic senescence). Leaf senescence also occurs in polycarpic perennials; even in "evergreen" species individual leaves senesce. In the annual model Arabidopsis thaliana sugars accumulate in the senescent leaves and senescence is accelerated by high sugar availability. Similar to A. thaliana, sugar contents increased with leaf age in the perennial Arabis alpina grown under warm conditions (22 C day/18 night). At 5 C, sugar contents in non-senescent leaves were higher than at a warm temperature, but dependent on the accession, either sugars did not accumulate or their contents decreased in old leaves. In A. alpina plants grown in their natural habitat in the Alps, sugar contents declined with leaf age. Growth at a cold temperature slightly delayed senescence in A. alpina. In both warm and cold conditions, an external glucose supply accelerated senescence, but natural variation was found in this response. In conclusion, sugar accumulation under warm conditions could accelerate leaf senescence in A. alpina plants, but genotype-specific responses and interactions with growth temperature are likely to influence senescence under natural conditions.