Effects of Exogenous Application of GA4+7 and NAA on Sugar Accumulation and Related Gene Expression in Peach Fruits During Developing and Ripening Stages

Sweetness is one of the key factors determining peach fruit quality. To better understand the molecular basis of gibberellic acid (GA) and 1-naphthaleneacetic acid (NAA) interference with sugar biosynthesis, a middle-late maturing commercial cultivar, ‘Jinxiu’ yellow peach fruit, was treated with three different concentrations of GA₄₊₇ and four of NAA. Fruit weight, firmness, total soluble solids, different sugar contents and the expression level of sugar-related genes were evaluated. The results showed that maximum increase in cv. ‘Jinxiu’ peach fruit size and sucrose content was with 1.25 mM GA₄₊₇, compared to control fruits and the other treatments during the ripening stages. The sucrose-phosphate synthase gene (PpSPS₂) which had a high level of expression and positive correlation with sucrose content was significantly regulated by 1.25 mM GA₄₊₇ in the final ripening stages. 0.5 mM NAA treatments significantly reduced the sucrose content and fruit size. Ninety percent of the fruits were deformed or dropped from the trees with treatments of 1 mM NAA and 2 mM NAA in the early development period. The crosstalk of different phytohormones and the related genes will be further investigated to get an insight into the inherent association between hormone control and sugar accumulation.

     

OsSHOC1 and OsPTD1 are essential for crossover formation during rice meiosis

Meiosis is essential for eukaryotic sexual reproduction and plant fertility, and crossovers (COs) are essential for meiosis and the formation of new allelic combinations in gametes. In this study, we report the isolation of a meiotic gene, OsSHOC1, and the identification of its partner, OsPTD1. Osshoc1 was sterile both in male and female gametophytes, and it showed a striking reduction in the number of meiotic COs, indicating that OsSHOC1 was required for normal CO formation. Further investigations showed that OsSHOC1 physically interacted with OsPTD1 and that the latter was also required for normal CO formation and plant fertility. Additionally, the expression profiles of both genes were consistent with their functions. Our results suggest that OsSHOC1 and OsPTD1 are essential for rice fertility and CO formation, possibly by stabilizing the recombinant intermediates during meiosis.     

Establishment and characterization of three immortal bovine muscular epithelial cell lines

We have established three immortal bovine muscular epithelial (BME) cell lines, one spontaneously immortalized (BMES), the second SV40LT-mediated (BMEV) and the third hTERT-mediated (BMET). The morphology of the three immortal cell lines was similar to that of early passage primary BME cells. Each of the immortal cell lines made cytokeratin, a typical epithelial marker. BMET grew faster than the other immortal lines and the BME cells, in 10% FBS-DMEM medium, whereas neither the primary cells nor the three immortal cell lines grew in 0.5% FBS-DMEM. The primary BME cells and the immortal cell lines, with the exception of BMES, made increasing amounts of p53 protein when treated with doxorubicin, a DNA damaging agent. On the other hand, almost half of the cells in populations of the three immortal cell lines may lack p16(INK4a) regulatory function, compared to primary BME cells that were growth arrested by enforced expression of p16(INK4a). In soft-agar assays, the primary cells and immortal cell lines proved to be less transformed in phenotype than HeLa cells. The three immortal epithelial-type cell lines reported here are the first cell lines established from muscle tissue of bovine or other species.     

In vitro selection of glyphosate-tolerant variants from long-term callus cultures of Zoysia matrella [L.] Merr

A complete protocol of in vitro selection and greenhouse screening for glyphosate-tolerant variants in manilagrass (Zoysia matrella [L.] Merr) was established in this study. Newly subcultured calli of more than 5?years?? old were transferred to selection medium containing 2?mM glyphosate. After two rounds of selection, 220 calli survived out of 840 and were transferred to regeneration medium without glyphosate. Regenerated plantlets were then transferred to regeneration medium containing 0.5?mM glyphosate to select tolerant plantlets. After 1-month growth, there were plantlets remained green and new shoots formed beside or on discolored explants. These surviving organisms were then transferred to fresh regeneration medium for further growth. Fully developed plantlets were transferred to a green house and then subjected to greenhouse screening by foliar spraying with 0.05?% glyphosate solution. Six glyphosate-tolerant plantlets, TP1-TP6, were obtained and proliferated for determination of sod-tolerance using morphological and physiological measurements. Fourteen days after foliar application with 0.1?% glyphosate, only TP5 showed enhanced sod-tolerance. The dark green color index value of TP5 was significantly higher than CK2, demonstrating that TP5 suffered less injury from glyphosate than CK2. Different physiological characters were also observed in CK1, CK2 and TP5. Significantly higher chlorophyll a content and catalase activity were observed in TP5 than in CK1. Fourteen days after treatment (DAT), the ion leakage, proline content and ascorbate peroxidase activity of CK2 and TP5 increased significantly, but the ion leakage of TP5 was significantly lower than that of CK2. The guaiacol peroxidase activity of TP5 increased significantly 14 DAT, and was significantly higher than that of CK1 and CK2. No change in shikimate content was observed in CK2 or TP5 14 DAT.     

Comparative study on spatial patterns of the Artemisia ordosica population in the Mu Us sandy land

Artemisia ordosica is an under-shrub species, which dominates the vegetation of the Mu Us sandy land in North China. The spatial patterns of the A. ordosica population in different sandy lands were compared with the methods of Spatial Auto-correlation Analysis, Semi-variance Analysis and Nine-Term Local Quadrat Variance (9TLQV). The results show that, by contrast with the A. ordosica population in fixed sandy land, the population in semi-fixed sandy land is of stronger auto-correlation and greater spatial heterogeneity, and meanwhile it presents more intense differentiation between patches and gaps. The spatial patterns of the A. ordosica population in semi-fixed sandy land are probably governed by drifting sand caused by strong winds. Drifting sand can easily put A. ordosica shrubs to death unless they live together in form of A. ordosica patches, where the distances between shrubs are short. In semi-fixed sandy land, patches are not only the form of the A. ordosica population to survive drifting sand, but also the foundation of the A. ordosica population to develop and broaden the area. The A. ordosica population is supposed to broaden the area through edge extending out from the patches scattering in semi-fixed sandy land. The spatial patterns of the A. ordosica population in fixed sandy land are possibly affected by intra-specific competition related to high plant coverage. This study is ecologically useful to improve the practice of vegetation restoration in sandy land. When transplanting A. ordosica shrubs to bare sandy land, one had better arrange them in form of patches separated by gaps, which can promote the survival of transplanted shrubs, and also help to take advantage of A. ordosica patches to revegetate bare gaps.     

SRIF及CSH对斜带石斑鱼脑垂体生长激素合成和分泌的调控

斜带石斑鱼 (Epinepheluscoioides)属于雌性先成熟、具有性转变的雌雄同体鱼类。生长激素释放抑制因子 (SRIF)是鱼类生长激素 (GH)分泌的主要抑制性调节剂 ,半胱胺 (CSH)可抑制SRIF的作用。本文采用静态孵育系统 ,应用RPA及RIA研究SRIF及CSH对斜带石斑鱼GHmRNA表达及GH分泌的调节。结果显示 ,SRIF能以剂量依存方式抑制斜带石斑鱼脑垂体释放GH ,时间越长作用越强。但SRIF作用 2 4h对GHmR NA水平的影响不显著 ,表明SRIF是斜带石斑鱼GH释放的抑制性调节剂 ,对GHmRNA的表达没有明显影响。较低剂量的CSH (10 -4- 10 -2 mol/L)使斜带石斑鱼的GH释放量增加 ,较高剂量 (10 -1mol/L)的CSH引起的GH增加趋势减缓 ,这种现象可能与较高剂量的CSH不仅抑制下丘脑SRIF的释放 ,同时影响GHRH的释放 ,使得GH的分泌量增幅下降有关 ;无论是较高剂量还是较低剂量的CSH都不能使GHmRNA的水平增加 ,表明CSH只能引起GH的释放量增加 ,不影响GH的合成。GnRH与CSH共同作用引起的GH释放量明显高于CSH单独作用的效应 ,其主要原因是由于GnRH促进GHmRNA的表达所致     

外源性磷酸肌酸临床效果观察

研究磷酸肌酸对缺血／再灌注损伤心肌的保护作用。方法对２０例进行双瓣膜替换术的患者,随机分成两组：实验组和对照组;分别于主动脉阻断前,开放后２、２４、４８小时抽血测定ＡＳＴ,ＬＤＨ,ＣＫ－ＭＢ,ＣＫ－ＭＭ和ｃＴｎｔ。结果主动脉开放后２小时实验组各指标均明显低于对照组;２４时达峰值。