华西雨屏区香樟人工林土壤表层细根生物量和碳储量

2010年11月-2011年12月, 研究了华西雨屏区31年生香樟人工林土壤表层(0～30 cm)细根生物量及碳储量.结果表明: 香樟人工林土壤0～30 cm层细根总生物量(活根+死根)和碳储量的平均值分别为1592.29 kg·hm^-2和660.68 kg C·hm^-2,其中活细根贡献率分别为91.1%和91.8%.随着土壤深度的增加,香樟1～5级活细根和死细根的生物量及碳储量均显著减少;随着根序等级的升高,香樟活细根生物量及碳储量显著增加.香樟细根总生物量及碳储量均在秋季最高、冬季最低,死细根生物量及碳储量为冬季最高、夏季最低;1级根和2级根生物量及碳储量均在夏季最高、冬季最低,而3~5级根则为秋季最高、冬季最低.土壤养分和水分的空间异质性是导致细根生物量和碳储量变化的主要原因.     

金荞麦果实中有效成分的分析

采用HPLC法对金荞麦果实中的有效成分进行了分析,结果表明:金荞麦果实中含有芦丁、槲皮素和表儿茶素等有效成分,其中主要以芦丁为主,槲皮素、表儿茶素等含量甚微.金荞麦果实中的有效成分主要集中在种子部分,果皮中则不合或含量甚微.     

野生和人工养殖鲤鱼口咽腔腭部结构与功能的初步研究

采用SONY DSC-F717数码相机记录了野生和人工养殖鲤鱼口咽腔腭部的形态学差异以及外源刺激对人工养殖鲤鱼口咽腔腭部的变化,并用KYKY-1000B扫描电镜和OLYMPUS DP70生物显微镜观察了鲤鱼口咽腔腭部的结构。结果表明:野生鲤鱼口咽腔的腭部密布栉状突起,而人工养殖鲤鱼口咽腔的腭部光滑平坦,机械刺激下口咽腔腭部的肌肉能强烈收缩,形成与野生鲤鱼栉状构造类似的圆锥状突起。与野生鲤鱼相比,人工养殖鲤鱼口咽腔腭部的味蕾和粘液细胞密度减小。这些变化可能与野生鲤鱼杂食性而人工养殖鲤鱼几乎完全吞食颗粒状配合饲料有关。     

Phenotyping of isogenic chlorophyll-less bread and durum wheat mutant lines in relation to photoprotection and photosynthetic capacity

Photosynthesis Research - In our experiments, we examined high light responses and photosynthetic capacity of chlorophyll-less isogenic mutant lines of hexaploid bread wheat (Triticum aestivum L.)...     

Comparison of RNA Editing Activity of APOBEC1-A1CF and APOBEC1-RBM47 Complexes Reconstituted in HEK293T Cells

RNA editing is an important form of regulating gene expression and activity. APOBEC1 cytosine deaminase was initially characterized as pairing with a cofactor, A1CF, to form an active RNA editing complex that specifically targets APOB RNA in regulating lipid metabolism. Recent studies revealed that APOBEC1 may be involved in editing other potential RNA targets in a tissue-specific manner, and another protein, RBM47, appears to instead be the main cofactor of APOBEC1 for editing APOB RNA. In this report, by expressing APOBEC1 with either A1CF or RBM47 from human or mouse in an HEK293T cell line with no intrinsic APOBEC1/A1CF/RBM47 expression, we have compared direct RNA editing activity on several known cellular target RNAs. By using a sensitive cell-based fluorescence assay that enables comparative quantification of RNA editing through subcellular localization changes of eGFP, the two APOBEC1 cofactors, A1CF and RBM47, showed clear differences for editing activity on APOB and several other tested RNAs, and clear differences were observed when mouse versus human genes were tested. In addition, we have determined the minimal domain requirement of RBM47 needed for activity. These results provide useful functional characterization of RBM47 and direct biochemical evidence for the differential editing selectivity on a number of RNA targets.     

Construction of a Microsatellite Linkage Map with Two Sequenced Rice Varieties

Based on the successful development of new microsatellite markers from the data of two whole-sequenced rice varieties, japonica variety Nipponbare and indica variety 9311, an F₂ population of 90 lines, which was derived from a single cross between Nipponbare and 9311, was applied to construct a genetic linkage framework map. The map covered 2 455.7 cM of total genomic length, and consisted of 152 simple sequence repeats (SSRs) loci including 46 pairs of new SSR primers developed by our research institute. The average genetic distance between two markers was 16.16 cM. In addition, markers RM345 and RM494, which have not been mapped on the Temnykh's map et al. (2001) were anchored on the sixth chromosome of this map. We compared this research with maps of Temnykh et al.(2001) and LAN et al. (2003) regarding the aspects of type and size of population, type and quantity of markers, and the marker arrangement order on chromosome, etc. Results indicated that the similarity of marker linear alignment was 93.81% between this map and T-map, Finally, the important significance of using sequenced rice varieties to construct linkage map was also discussed.     

Genetic Analysis and Molecular Tagging on a Novel Excessive Tillering Mutant in Rice

A rice (Oryza sativa L.) mutant with an excessive tiller number, designated ext-M1B, was found in the F₂ progenies generated from the cross between M1B and GMS-1 (a genetic male sterile), whose number of tillers was 121. The excessive tillering mutant also resulted in significant changes in plant height, flag leaf, stem, filled grains per panicle, and productive panicles per plant. The inbreeding progenies of ext-M1B exhibited the same mutant phenotype. The crosses from ext-M1B/M1B, M1B/ext-M1B, 2480B/ext-M1B, D62B/ext-M1B, G46B/ext-M1B, and G683B/ext-M1B expressed normal tillering in F₁, and segregated into two different phenotypes of normal tillering type and excessive tillering type in a ratio of 3:1 in F₂. Inheritance analysis indicated that the excessive tillering character was controlled by a single recessive nucleic gene. By BSA (bulked segregants analysis) and microsatellite makers with the F₂ population of 2480B/ext-M1B as the mapping population, RM197, RM584, and RM225, all of which were located on the short arm of rice chromosome 6, were identified to be linked with the excessive tillering gene with genetic distance of 3.8 cM, 5.1 cM, and 5.2 cM, respectively. This gene is probably a new excessive tillering gene in rice and is designated tentatively ext-M1B (t).     

Genetic Diversity Analysis of Tibetan Wild Barley Using SSR Markers

One hundred and six accessions of wild barley collected from Tibet, China, including 50 entries of the two-rowed wild barley Hordeum vulgare ssp. spontaneum (HS), 29 entries of the six-rowed wild barley Hordeum vulgare ssp. agriocrithon (HA), and 27 entries of the six-rowed wild barley Hordeum vulgare ssp. agriocrithon var. lagunculiforme (HL), were analyzed using 30 SSR markers selected from the seven barley linkage groups for studying genetic diversity and evolutionary relationship of the three subspecies of Tibetan wild barley to cultivated barley in China. Over the 30 genetic loci that were studied, 229 alleles were identified among the 106 accessions, of which 70 were common alleles. H. vulgare ssp. spontaneum possesses about thrice more private alleles (2.83 alleles/locus) than HS (0.93 alleles/locus), whereas almost no private alleles were detected in HL. The genetic diversity among-subspecies is much higher than that within-subspecies. Generally, the genetic diversity among the three subspecies is of the order HS > HL > HA. Phylogenetic analysis of the 106 accessions showed that all the accessions of HS and HA was clustered in their own groups, whereas the 27 accessions of HL were separated into two groups (14 entries with group HS and the rest with group HA). This indicated that HL was an intermediate form between HS and HA. Based on this study and previous works, we suggested that Chinese cultivated barley might evolve from HS via HL to HA.     

脊椎动物FoxO基因亚族的进化

本研究以脊椎动物FoxO作为研究对象,选取NCBI上公布的多个FoxO基因编码蛋白的核苷酸序列,重点分析Fox O蛋白质结构和功能的相似性与差异性,重建FoxO基因的系统发育树并进行选择压力分析,对FoxO基因亚族的起源和进化进行研究分析。结果显示:脊椎动物FoxO蛋白间Forhead结构域十分保守但核定位信号区结构差异较明显,尤其是FoxO6蛋白,并且多个磷酸化位点在哺乳动物FoxO6中缺失,削弱核输出信号,但在斑马鱼和原鸡的FoxO6中未缺失这些位点,推测其胞质定位调控作用仍十分重要。FoxO3中多个磷酸化位点可能与寿命延长作用相关。系统发育树表明FoxO1是FoxO基因的祖先基因,不同FoxO基因进化速率不同。选择压力分析结果显示FoxO基因过程每个位点经历不同的选择压,并且获得25个正选择位点,这些正选择位点可能对FoxO不同基因的形成和新功能的产生中具有十分重要的作用。