KAv-1 is Better Suited to Chick Fibroblast Culture than DMEM or 199 Media

Cultured cells are a useful resource for poultry scientists, since these cells allow scientists to evaluate biological responses to conditions such as infectious diseases in vitro while mimicking the whole-body response in birds. However avian cell culture requires an optimized basal medium, and there are currently relatively few options for this basal medium (medium 199 and KAv-1). This means that there is still room for the development of an optimal basal medium for avian cell culture. Here we compare KAv-1 medium, Dulbecco''s modified Eagle medium (DMEM) and medium 199 during the culture of chick fibroblasts and determine that KAv-1 remains the optimal medium for these assays. Our results show that DNA damage is reduced in fibroblasts cultured in the KAv-1 medium, when compared to both DMEM and Medium 199 and that these cells also display improved growth dynamics in KAv-1 medium when compared to both DMEM and medium 199. To the best of our knowledge, this is the first study to describe a comparative analysis of culture media for avian cells, which would provide useful information for poultry scientists.     

保鲜剂对唐菖蒲切花延衰的生理作用

用保鲜剂对唐菖蒲品种“金色原野”切花进行处理,测定切花的抗氧化酶活性和膜脂过氧化水平。结果表明：保鲜剂均可提高切花的含水量,使细胞相对膜透性减小,可溶性蛋白降解减缓,保护酶活性增强,丙二醛积累量减少,活性氧生成减缓,从而延长切花瓶插寿命,提高切花的观赏品质。     

Bioregulatory Effects of the Fungicidal Strobilurin Kresoxim-methyl in Wheat (Triticum aestivum)

Apart from its fungicidal effect, the strobilurin kresoxim-methyl (BAS 490 F) was found to induce physiological and developmental alterations in wheat (Triticum aestivum L.) which are seen in connection with improved yield. In a series of biotests including heterotrophic maize and photoautotrophic algal cell suspensions, duckweed, isolated mustard shoots and germinating cress seeds, kresoxim-methyl showed a similar response pattern to standard auxins (e.g. indol-3-ylacetic acid, IAA; 2-(1-naphthyl)acetic acid, α-NAA). Auxin-like activity of kresoxim-methyl was also found when stem explants of tobacco were cultured on a hormone-free medium. Kresoxim-methyl stimulated shoot formation, particularly at 10^-7 M . The same effect was induced by 10^-8 M IAA. The determination of phytohormone-like substances in shoots of wheat plants foliar-treated with 7×10^-4 M kresoxim-methyl revealed only slightly changed levels of endogenous IAA, gibberellins and abscisic acid. In contrast, the contents of dihydrozeatin riboside-type cytokinins increased to 160% of the control, while trans-zeatin riboside- and isopentenyladenosine-type cytokinins remained nearly unchanged. The most remarkable alterations were the reductions in 1-aminocyclopropane-1-carboxylic acid (ACC) levels and ethylene formation which were demonstrated in intact plants, leaf discs and the shoots of wheat subjected to drought stress. Kresoxim-methyl affected the induction of ACC synthase activity which converts S-adenosyl-methionine to ACC in ethylene biosynthesis. In shoots from foliar-treated wheat plants, 10^-4 M kresoxim-methyl inhibited stress-induced increases in endogenous ACC synthase activity, ACC levels and ethylene formation by approximately 50%. Reductions in ACC synthase activity and ACC levels of 30% were also obtained at low concentrations of α-NAA (10^-6 M ). In contrast, ACC synthase activity in vitro was not influenced by adding the compounds. In wheat leaf discs, the inhibiting effect of kresoxim-methyl, α-NAA and IAA on ethylene formation was accompanied by delayed leaf senescence, characterized by reduced chlorophyll loss. However, in contrast to kresoxim-methyl which showed only inhibitory activity on ethylene synthesis over a wide range of concentrations applied, the auxins stimulated ethylene production at high concentrations of about 10^-4 M . The inhibition of ethylene biosynthesis by kresoxim-methyl, together with an increase in endogenous cytokinins could explain the retardation of senescence and the intensified green leaf pigmentation in wheat exposed to this strobilurin. © 1997 SCI.     

miR-17 regulates senescence of rat vascular smooth muscle cells

AIM: To investigate the effect of microRNA-17 (miR-17) on the senescence of vascular smooth muscle cells (VSMCs) and the underlying mechanism.METHODS: The medial layer of the thoracic aorta was collected from the SD rats and isolated for primary culture. VSMCs were identified by immunofluorescence staining. The VSMCs were collected at the 4th~6th generations, and then the miR-17 mimics and miR-17 inhibitor were transfected into the VSMCs by liposome method. After 24 h, the cell senescence was induced by D-galactose. The VSMCs were divided into the following 6 groups:aging induction+miR-17 mimics (A-miR-17) group, aging induction+miR-17 inhibitor (A-anti-miR-17) group, A-control group, normal (N)+miR-17-mimics (N-miR-17) group, N-anti-miR-17 group, and N-control group. On day 3 after the addition of D-galactose, the senescence of VSMCs was observed with β-galactosidase staining. The expression of miR-17, p16 and p21 was detected by RT-qPCR and immunohistochemistry. RESULTS: miR-17 expression in the VSMCs was significantly lower in A-control group than that in N-control group (P<0.01). Compared with A-control group, the expression of miR-17 in the VSMCs was significantly increased in A-miR-17 group (P<0.01), while that was significantly decreased in A-anti-miR-17 group (P<0.01). The number of β-galactosidase positive staining cells in A-anti-miR-17 group was significantly higher than that in A-miR-17 group (P<0.01). The expression of p21 at mRNA and protein levels in the VSMCs was significantly lower in A-miR-17 group than that in A-control group (P<0.01), and the expressions of p21 at mRNA and protein levels was significantly higher in A-anti-miR-17 group than that in A-miR-17 group (P<0.01). CONCLUSION: miR-17 inhibits rat VSMCs senescence induced by D-galactose, the underlying mechanism is associated with the inhibition of p21 expression.     

氯化钙处理对滑子菇采后贮藏品质的影响

文章研究了氯化钙处理对滑子菇保鲜效果的影响。结果表明,氯化钙处理不仅降低了滑子菇的失重率、开伞率、褐变度和褐变的速率,而且还降低了膜的过氧化,延缓了滑子菇衰老,增强了滑子菇的抗氧化能力,有效保持滑子菇品质,减少了营养流失。贮藏期间,滑子菇氯化钙处理组抗坏血酸含量始终高于对照组,有效保持滑子菇清除自由基能力。     

水稻类病斑早衰突变体lmps1的表型鉴定与基因定位

经甲基磺酸乙酯(EMS)诱变优良籼型水稻恢复系缙恢10号,获得一个稳定遗传的水稻类病斑早衰突变体lmps1(lesion mimic and premature senescence 1)。该突变体苗期表型正常,分蘖早期出现褐色类病斑,且斑点数目随植株生长而增多,孕穗期叶片开始萎黄衰老。与野生型相比,突变体lmps1的每穗总粒数下降8%(P0.05),株高、穗长、有效穗数、每穗实粒数、结实率以及千粒重分别下降14.3%、24.3%、27.2%、50%、45.7%与14.5%,差异均达极显著水平(P0.01)。遮光处理表明,突变体lmps1的类病斑性状受光照诱导。孕穗期叶片光合色素含量下降且光合效率降低, H2O2含量增加,抗氧化酶SOD和CAT的活性显著降低。透射电镜观察结果显示,突变体lmps1叶肉细胞中叶绿体数目减少,叶绿体的类囊体片层结构损伤降解。qRT-PCR结果显示,突变体lmps1中防卫反应相关基因除POX22.3表达量降低外,POC1、PAL、PBZ1、PR1、NPR1、PR5表达量均极显著高于野生型。遗传分析表明突变体lmps1的类病斑早衰性状受1对隐性核基因控制,利用西农1A与突变体lmps1杂交所得F2群体中的突变株,将目标基因定位于第7染色体长臂端粒附近约167.3 kb的物理区段内。     

田间密植诱导抽穗期玉米叶片衰老时的光合作用机制

为理解田间密植是否诱导抽穗期玉米叶片衰老以及衰老叶片的光合作用规律和机制,本研究以玉米"先玉335"为材料研究了抽穗期栽培密度对穗位叶和穗下第4叶的光环境、比叶重、氮素含量、叶绿素含量、气体交换以及叶绿素荧光诱导动力学的影响。结果表明,随着密度的增加玉米冠层内的光强大幅降低,尤其穗下第4叶;穗位叶和穗下第4叶的比叶重降低。同时,穗位叶和穗下第4叶的氮素含量和叶绿素含量均随栽培密度增加而下降。不同栽培密度下穗位叶荧光诱导动力学曲线(OJIP)未发生明显改变,而高密度下穗下第4叶OJIP的J和I相的相对荧光产量较低密度有提高趋势。高密度下,穗位叶和穗下第4叶叶片的光合速率、气孔导度和蒸腾速率均降低;不过,穗位叶胞间CO2浓度降低,穗下第4叶胞间CO2浓度增加。我们认为,田间密植条件下异质性光环境可以迅速诱导抽穗期玉米冠层下部叶片(如穗下第4叶)衰老;该过程中,光合作用的限制因素不是光能吸收和电子传递,而可能是碳同化。     

Rb1 protects human umbilical vein endothelial cells from hydrogen peroxide-induced senescence:involvement of caveolin-1

AIM: Endothelial cell senescence has been proposed to be involved in endothelial dysfunction and atherogenesis. This study aims to investigate the effects of ginsenoside Rb1, a major constituent of ginseng, on hydrogen peroxide (H₂O₂)-induced endothelial cell senescence, and to explore the expression and production of caveolin-1 in H₂O₂-induced premature senescence.METHODS: The senescence of primary human umbilical vein endothelial cells (HUVECs) was induced by H₂O₂ as judged by morphology inspection, senescence-associated β-galactosidase (SA-β-Gal) staining and cell cycle detection. The protein expression of caveolin-1 was determined by Western blot and confocal laser-scanning microscopy.RESULTS: Treatment of the HUVECs with H₂O₂ at 60 μmol/L induced premature senescence, as judged by enlarged, flattened cell morphology, increased SA-β-Gal activity and sustained growth arrest. H₂O₂ effectively increased caveolin-1 level. Pretreatment of the HUVECs with Rb1 was found to reverse endothelial cell senescence, as witnessed by a significant decrease in senescent cell numbers and a decreased percentage of G₀/G₁ phase cells. Furthermore, Rb1 administration reversed the H₂O₂-increased protein level of caveolin-1.CONCLUSION: Ginsenoside Rb1 antagonizes H₂O₂-induced endothelial cell senescence through caveolin-1 modulation.     

甘蔗叶片衰老与内源多胺和抗氧化代谢的关系研究

通过典范相关和主因子分析对甘蔗叶片衰老与内源多胺和抗氧化代谢的关系进行研究表明,在甘蔗叶片衰老过程中,游离多胺含量急剧下降,其速降期早于蛋白质的降解期,且与活性氧的产生和清除有密切关系。供试甘蔗品种＋４叶ＳＯＤ、ＣＡＴ活性、ＧＳＨ含量下降,活性氧清除能力降低,Ｏ２＾－产生增加,导致ＭＤＡ含量急剧上升,其中Ｇ、Ｔ、１１变化更大,更易早衰,可见内源多胺和抗氧化代谢变化是引起甘蔗叶片衰老的重要原因。     

小麦叶片衰老的超微立体学研究及6-苄氨基嘌呤的作用

用电子显微镜和立体学方法考察了自然条件下小麦叶片衰老过程中超微结构的立体学参数变化及６－苄氨基嘌呤的调节作用,结果表明：在叶片衰老过程中叶绿体的体积膨胀且由椭球形变为球形,其体密度,面密度和数密度均下降,基粒变小且失去严整性,类囊体膨胀,但每叶绿体中基粒的数目在衰老早期是增加的;ＢＡ能够维持叶绿体和基粒结构,形态的稳定,对各立体学参数均有一定影响。