提高籼稻花药培养效率的研究

改变碳源可显著提高大麦花粉胚的频率,但碳源对水稻花培的作用则研究不多。本试验以150mM 蔗糖为对照,比较同样浓度的半乳糖、果糖、葡萄糖、麦芽糖、山梨糖、甘露糖、75mM 甘露醇 75mM 蔗糖,75mM 山梨醇 75mM 蔗糖以及25mg/L 马铃薯可溶性淀粉 75mM 蔗糖(均系 Sigma 公司产品)对3个籼稻品种花药愈伤组织诱导率的作用。结果表明     

水稻耐贮藏基因（lox-3）DH作图群体构建方法的比较研究

以与水稻耐贮藏材料（Daw Dam）有丰富分子标记多态性的常规材料2070、明恢63、Dulur/协青早B为亲本,分别与之杂交,采用改良一步成苗花药培养法对其F1代进行花药培养,以一步成苗法为对照,评价新方法在构建耐贮藏基因DH作图群体中的应用潜力。研究结果表明,改良一步成苗法显著地提高了愈伤组织分化率、植株再生率、绿苗率、绿苗素质,而且得到的加倍单倍体系田间表现良好,是构建耐贮藏基因DH作图群体的理想方法,但在不同基因型间表现有一定的差异性,其中Daw Dam/2070、Daw Dam/明恢63组合的培养效率有较大增幅。利用改良一步成苗法已获得一定数量的DH群体,为开展进一步研究奠定了基础。 Abstract:Crosses were produced by using a storable rice variety (Daw Dam) and 2070,Ming Hui 63,as well as Dulur/Xie Qing Zao B as parents,among these materials there are abundant polymorphisms of DNA molecular markers.Their F1's were applied to generate DH lines by an improved method of direct induction of pollen plant.The method of the direct induction of pollen plant was used as check treatment to evaluate the improved method.The results showed that the improved method increased the re-differentiation percentage of pollen callus,the percentage of regeneration plantlets,and the percentage of green regeneration plantlets and produced more vigorous seedlings.The improved method was a competent method of establishing DH population for mapping lox-3 gene.It was also showed that the efficiency of the new method was different among genotypes and out of three experimental crosses Daw Dam/2070 and Daw Dam/Minghui 63 showed more efficient.More than 60 DH lines have been obtained in this experiment.     

Vegetation and Climate Variations at Taibai, Qinling Mountains in Central China for the Last 3 500 cal BP

Pollen records of two swamp sections, located at Taibai Mountain, the highest peak in the Qinling Mountains of central China, show variations of vegetation and climate for the last 3 500 cal BP. The pollen assemblage at the Foyechi and Sanqingchi sections and the surface soil pollen allowed us to reconstruct a high-altitude vegetation history at Taibai Mountain for the first time. The data indicated that there was a cold-dry climate interval between 3 500 and 3 080 cal BP and a relatively warm and wet period compared with the present from 3 080 to 1 860 cal BP. The warmest period in the late Holocene on Taibai Mountain was from 1 430 to 730 cal BP, with an approximate 2℃ increase in mean annual temperature compared with today.There was a relatively cool-dry climate interval from 730 to 310 cal BP. After 310 cal BP, a mountain tundra vegetation developed again and the position of the modern tree line was established.     

极端干旱区沙土掩埋对凋落物分解速率及盐分含量动态的影响

极端干旱区由于降水稀少, 植被盖度低, 太阳辐射强烈, 以及土壤稳定性差, 导致其凋落物周转不同于非干旱区。为探究极端干旱区凋落物分解规律, 该研究利用凋落物分解袋法, 以塔克拉玛干沙漠南缘沙漠-绿洲过渡带优势物种花花柴(Karelinia caspia)、骆驼刺(Alhagi sparsifolia)和胡杨(Populus euphratica)凋落叶为研究对象, 设置不同的沙土掩埋处理: 地表、2 cm和15 cm埋深, 以模拟自然条件下凋落物分解环境, 测定分解过程中凋落物质量和水溶性盐的变化特征。结果表明: 极端干旱区凋落物分解速率与凋落物初始碳(C)含量、氮(N)含量、C:N和木质素含量的关系与非干旱区存在较大差异, 在地表处理下, 木质素含量越高, 质量损失越快。不同分解环境下凋落物质量和水溶性盐损失具有显著差异, 与15 cm埋深相比, 地表和2 cm埋深处理显著增加了凋落物的质量损失和水溶性盐总量损失。地表处理增加了凋落物分解前期的水溶性盐溶解量。该研究表明, 极端干旱区凋落物分解的驱动机制具有独特性, 由于降水稀少, 土壤微生物的活性较低, 掩埋深度不是驱动凋落物分解的主要因素, 极端干旱区凋落物的分解主要受其他非生物过程如太阳光辐射的影响。     

Bulk endocytosis at neuronal synapses

Neurotransmitter-containing synaptic vesicle(SV)fusion with the nerve terminal plasma membrane initiates neurotransmission in response to neuronal excitation.Under mild stimulation,the fused vesicular membrane is retrieved via kiss-and-run and/or clathrin-mediated endocytosis,which is sufficient to maintain recycling of SVs.When neurons are challenged with very high stimulation,the number of fused SVs can be extremely high,resulting in significant plasma membrane addition.Under such conditions,a higher capacity retrieval pathway,bulk endocytosis,is activated to redress this large membrane imbalance.Despite first being described more than 40 years ago,the molecular mechanisms underpinning this important process have yet to be clearly defined.In this review,we highlight the current evidence for bulk endocytosis and its prevalence in various neuronal models,as well as discuss the underlying molecular components.     

Crystal structure of a plant leucine rich repeat protein with two island domains

Leucine rich repeat(LRR)domain,characterized by a repetitive sequence pattern rich in leucine residues,is a universal protein-protein interaction motif present in all life forms.LRR repeats interrupted by sequences of 30 70 residues(termed island domain,ID)have been found in some plant LRR receptor-like kinases(RLKs)and animal Toll-like receptors(TLR7-9).Recent studies provide insight into how a single ID is structurally integrated into an LRR protein.However,structural information on an LRR protein with two IDs is lacking.The receptor-like protein kinase 2(RPK2)is an LRR-RLK and has important roles in controlling plant growth and development by perception and transduction of hormone signal.Here we present the crystal structure of the extracellular LRR domain of RPK2(RPK2-LRR)containing two IDs from Arabidopsis.The structure reveals that both of the IDs are helical and located at the central region of the single RPK2-LRR solenoid.One of them binds to the inner surface of the solenoid,whereas the other one mainly interacts with the lateral side.Unexpectedly,a long loop immediately following the N-terminal capping domain of RPK2-LRR is presented toward and sandwiched between the two IDs,further stabilizing their embedding to the LRR solenoid.A potential ligand binding site formed by the two IDs and the solenoid is located at the C-terminal side of RPK2-LRR.The structural information of RPK2-LRR broadens our understanding toward the large family of LRR proteins and provides insight into RPK2-mediated signaling.     

云南人群系统性红斑狼疮与TNF微卫星基因座关系的研究

位于MHC内的肿瘤坏死因子（tomornecrosisfactor,TNF）基因区域有5个微卫星基因座a、b、c、d和e,本研究调查了中国云南汉族系统性红斑狼疮（systemiclupuserythematosus,SLE）与这几个微卫星基因座多态性的关系。本文用荧光标记引物和半自动基因扫描方法对云南地区97例SLE患者及79例健康对照者的这5个微卫星基因座进行了基因分型,结果发现,SLE患者的TNFa1（P=0.0206）,c2(P=0.0000)等位基因频率较正常人显著增高,而TNFa2(P=0.0163),c3(P=0.0065),c4(P=0.0012),d6(P=0.0448)等位基因频率则是正常对照较SLE患者高。同时我们还发现在这5个微卫星基因座中,与白种人比较中国人出现了尚未发现的新等位基因。 Abstract：We have investigated TNF microsatellite polymorphism in SLE.A total of 97 Chinese Han SLE patients and 79 matched Chinese Han controls were studied in this study, TNF microsatellites a,b,c,d and e were typed using fluorescent labeled automated genescanning and genotyping.TNFa1（P=0.0206）,c2 (P=0.0000) allele frequencies were significantly increased in the SLE group comparing with controls,and TNF a2 (P=0.0163) c3(P=0.0065),c4(P=0.0012),d6(P=0.0448) allele frequencies were significantly increased in controls.Meanwhile,we found some new alleles in Chinese which are different form those in Caucasoids.     

Research of blastocyte-like structure in chicken

Embryonic stem (ES) cells known to be one of the most brilliant stars enlightening the biology science are a major tool to investigate embryonic development and differentiation, functional genomics and applied in medicine territory for cellular therapy. Even though some scientists have already established cultural sys-tems for selection and maintenance of putative avian ES cells, the study on them still drops behind the mammalian and proceeds slowly. The avian ES cells can be used to produce…     

Establishment of trophic continuum in the food web of the Yellow Sea and East China Sea ecosystem: Insight from carbon and nitrogen stable isotopes

The determination of trophic level for the biology in a marine ecosystem is very important as alteration of its structure and function may be reflected in the tro-phic level of component species. A change in trophic level indicates variation in an organism’s feeding bi-ology or in the pathway of energy flow from primary producers to the consumer. The gut content analysis is a traditional method for studying trophodynamics of food web in marine ecosystems. Species composition and amounts in al…     

Construction, detection and microarray analysis on theShigella flexneri 2asitC mutant

Bacteria of Shigella spp. are commonly called Ba-cillus dysenteriae. The bacillary dysentery caused byShigella is one of the most serious infectious diseasesthroughout the world, especially in the developing countries. The completion of whole genome sequenc-ing of Shigella flexneri 2a strain 301 (brieflySf301)[1] offered a large amount of information andinvaluable clues for its functional genomic research.Microbial functional genomic research aims at deeplyinterpreting the function of genes …