洋葱大葱种间杂种鉴定方法建立与应用

以洋葱、大葱及其杂种F1为材料,利用PCR-RFLP技术对其核糖体DNA内部转录间隔区（ITS）和细胞质线粒体DNA的srRNA基因V7进行分析,试图建立洋葱大葱种间杂种的鉴定方法。结果显示：大葱ITS序列没有DdeⅠ酶切位点;而洋葱被DdeⅠ酶切成两个大小不同的片段;F1杂种具有两亲本的ITS序列酶切模式。细胞质线粒体srRNA基因的V7区域的扩增表明F1杂种和亲本有大小一致的单一片段,经RsaI酶切后,大葱有约0.3 kb条带,比洋葱的稍小,两亲本都含有另外一条小条带（约0.1 kb）。对25份杂种材料进行鉴定,22份的母本为大葱,3份为假杂种。本研究在分子水平上建立了洋葱大葱种间杂种的鉴定方法,快速、准确的辨别杂种一代的真假性。     

植物角质层蜡质基因的研究进展

角质层是覆盖在植物地上部分最表层的保护层,具有降低植物表面的水分散失、防止紫外线辐射伤害和抵抗病虫害侵入等环境胁迫等功能,在植物适应外界环境作用方面起重要作用.作对近年来角质层蜡质基因的研究进展进行综述,同时也对蜡质基因的研究前景提出一些看法.     

Molecular Evolution of Drosophila Cuticular Protein Genes

Several multigene families have been described that together encode scores of structural cuticular proteins in Drosophila, although the functional significance of this diversity remains to be explored. Here I investigate the evolutionary histories of several multigene families (CPR, Tweedle, CPLCG, and CPF/CPFL) that vary in age, size, and sequence complexity, using sequenced Drosophila genomes and mosquito outgroups. My objective is to describe the rates and mechanisms of ‘cuticle-ome’ divergence, in order to identify conserved and rapidly evolving elements. I also investigate potential examples of interlocus gene conversion and concerted evolution within these families during Drosophila evolution. The absolute rate of change in gene number (per million years) is an order of magnitude lower for cuticular protein families within Drosophila than it is among Drosophila and the two mosquito taxa, implying that major transitions in the cuticle proteome have occurred at higher taxonomic levels. Several hotspots of intergenic conversion and/or gene turnover were identified, e.g. some gene pairs have independently undergone intergenic conversion within different lineages. Some gene conversion hotspots were characterized by conversion tracts initiating near nucleotide repeats within coding regions, and similar repeats were found within concertedly evolving cuticular protein genes in Anopheles gambiae. Rates of amino-acid substitution were generally severalfold higher along the branch connecting the Sophophora and Drosophila species groups, and 13 genes have Ka/Ks significantly greater than one along this branch, indicating adaptive divergence. Insect cuticular proteins appear to be a source of adaptive evolution within genera and, at higher taxonomic levels, subject to periods of gene-family expansion and contraction followed by quiescence. However, this relative stasis is belied by hotspots of molecular evolution, particularly concerted evolution, during the diversification of Drosophila. The prominent association between interlocus gene conversion and repeats within the coding sequence of interacting genes suggests that the latter promote strand exchange.     

The Prevalence of Pores and Canals in Leaf Cuticular Membranes

Ubiquitous, visibly discrete, natural cuticular pores and transcuticularcanals were found in the dewaxed leaf (and one herbaceous stem)cuticular membranes of 27 out of 32 taxa among 14 families.Clear evidence for their existence is provided by light photomicrographs.Both adaxial and abaxial leaf surfaces were investigated usingthin transections and chemically isolated cuticular membranes,in conjunction with ordinary staining techniques and light microscopymethods. No correlations were found between cuticle thicknessesand either the frequency of pore or the pore and canal diameters. Leaf cuticles, cuticle morphology, cuticular pores, transcuticular canals, cuticular flanges     

RNA-Seq Analysis Reveals MAPKKK Family Members Related to Drought Tolerance in Maize

The mitogen-activated protein kinase (MAPK) cascade is an evolutionarily conserved signal transduction pathway that is involved in plant development and stress responses. As the first component of this phosphorelay cascade, mitogen-activated protein kinase kinase kinases (MAPKKKs) act as adaptors linking upstream signaling steps to the core MAPK cascade to promote the appropriate cellular responses; however, the functions of MAPKKKs in maize are unclear. Here, we identified 71 MAPKKK genes, of which 14 were novel, based on a computational analysis of the maize (Zea mays L.) genome. Using an RNA-seq analysis in the leaf, stem and root of maize under well-watered and drought-stress conditions, we identified 5,866 differentially expressed genes (DEGs), including 8 MAPKKK genes responsive to drought stress. Many of the DEGs were enriched in processes such as drought stress, abiotic stimulus, oxidation-reduction, and metabolic processes. The other way round, DEGs involved in processes such as oxidation, photosynthesis, and starch, proline, ethylene, and salicylic acid metabolism were clearly co-expressed with the MAPKKK genes. Furthermore, a quantitative real-time PCR (qRT-PCR) analysis was performed to assess the relative expression levels of MAPKKKs. Correlation analysis revealed that there was a significant correlation between expression levels of two MAPKKKs and relative biomass responsive to drought in 8 inbred lines. Our results indicate that MAPKKKs may have important regulatory functions in drought tolerance in maize.     

快速提取大葱细胞DNA的方法

经匀浆－差速离心－裂解－纯化等骤,可获得纯度较高的胸质DNA,DNA产率1－2ug/g^-1(FW).此法比传统的方法用材少,对仪器的要求不高,成本低,提取时间短,每人每天提取24个样品,适合大量样品分析。     

Single-Cell RNA-Seq Reveals AML Hierarchies Relevant to Disease Progression and Immunity

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RNA-Seq of the Nucleolus Reveals Abundant SNORD44-Derived Small RNAs

Small non-coding RNAs represent RNA species that are not translated to proteins, but which have diverse and broad functional activities in physiological and pathophysiological states. The knowledge of these small RNAs is rapidly expanding in part through the use of massive parallel (deep) sequencing efforts. We present here the first deep sequencing of small RNomes in subcellular compartments with particular emphasis on small RNAs (sRNA) associated with the nucleolus. The vast majority of the cellular, cytoplasmic and nuclear sRNAs were identified as miRNAs. In contrast, the nucleolar sRNAs had a unique size distribution consisting of 19–20 and 25 nt RNAs, which were predominantly composed of small snoRNA-derived box C/D RNAs (termed as sdRNA). Sequences from 47 sdRNAs were identified, which mapped to both 5′ and 3′ ends of the snoRNAs, and retained conserved box C or D motifs. SdRNA reads mapping to SNORD44 comprised 74% of all nucleolar sdRNAs, and were confirmed by Northern blotting as comprising both 20 and 25 nt RNAs. A novel 120 nt SNORD44 form was also identified. The expression of the SNORD44 sdRNA and 120 nt form was independent of Dicer/Drosha–mediated processing pathways but was dependent on the box C/D snoRNP proteins/sno-ribonucleoproteins fibrillarin and NOP58. The 120 nt SNORD44-derived RNA bound to fibrillarin suggesting that C/D sno-ribonucleoproteins are involved in regulating the stability or processing of SNORD44. This study reveals sRNA cell-compartment specific expression and the distinctive unique composition of the nucleolar sRNAs.     

Environmental Pollution: Leaf Cuticular Patterns in Trifolium pratense L.

Red clover populations collected from the polluted environmentsof Memphis, Nashville, and Knoxville (Tennessee) showed decreasedfloral production, low stomatal frequency, high trichome density,and longer trichomes. The results for plant population collectedfrom a less polluted, rural Reelfoot Lake area were quite theopposite. Subsidiary cell complex remained the same in all thepopulations, while stomatal size range showed little variation.     

Compositae Plants Differed in Leaf Cuticular Waxes between High and Low Altitudes

We sampled eight Compositae species at high altitude (3482 m) and seven species at low altitude (220 m), analyzed the chemical compositions and contents of leaf cuticular wax, and calculated the values of average chain length (ACL), carbon preference index (CPI), dispersion (d), dispersion/weighted mean chain length (d/N), and C₃₁/(C₃₁ + C₂₉) (Norm31). The amounts of total wax and compositions were significantly higher at high altitude than at low altitude, except for primary alcohol, secondary alcohol, and ketone. The main n‐alkanes in most samples were C₃₁, C₂₉, and C₃₃. Low altitude had more C₃₁ and C₃₃, whereas more C₂₉ occurred at high altitude. The ACL, CPI, d, d/N, and Norma 31 were higher at low altitude than at high altitude. The fatty acid and primary alcohol at low altitude contained more C₂₆ homologous than at high altitude. More short‐chain primary alcohols were observed at high altitude. At low altitude, the primary alcohol gave on average the largest amount, while it was n‐alkane at high altitude. These results indicated that the variations of leaf cuticular waxes benefited Compositae plants to adapt to various environmental stresses and enlarge their distribution.     

Changes in Microtubules in Onion Leaf Sheath Cells during Bulb Development

Cortical microtubules are oriented transversely to the cellaxis in leaf sheath cells of onion plants (Allium cepa L. cv.Osaka-Okute) that have not started bulb formation. As the bulbdevelops and the leaf sheath cells swell, the microtubules becomedisoriented and scattered and finally disappear. The microtubuleinhibitors colchicine and cremart [O-ethyl O-(3-methyl-6-nitrophenyl)N-sec-butylphosphorothioamidate]cause swelling of leaf sheath cells and make the basal partof the plant bulbous. The cortical microtubules may have animportant role in regulating bulb development in onion plants. (Received August 21, 1982; Accepted December 6, 1982)