自由基清除剂对延缓青花菜花蕾衰老的效应

青花菜采后花蕾迅速衰老，叶绿素和蛋白质含量明显下降，超氧物歧化酶（ＳＯＤ）和过氧化氢酶（ＣＡＴ）活性随衰老进程先升高而后下降，丙二醛（ＭＤＡ）持续增加，细胞膜透性迅速增大。２０ｍｇ／Ｌ６－苄基腺嘌呤（６－ＢＡ）处理明显延缓叶绿素和蛋白质的降解，提高ＳＯＤ活性，对ＣＡＴ激活尤为明显，抑制了Ｈａｂｅｒ－Ｗｅｉｓｓ反应，降低过氧化氢（Ｈ２Ｏ２）和羟基自由基（ＯＨ）含量，延缓膜脂过氧化作用，降低子ＭＤＡ含量，减小膜渗漏，延缓花蕾衰老。２０ｍｇ／Ｌ６－ＢＡ中加入０２％苯甲酸钠（ＳＢＮ），对６－ＢＡ产生的各种延衰效应均有增效作用，进一步推迟花蕾衰老。２００ｍｇ／Ｌ抗坏血酸（ＡｓＡ）促进叶绿素和蛋白质降解，在提高ＳＯＤ和ＣＡＴ活性的同时，ＭＤＡ反而明显增加，膜透性迅速增大，加速衰老。     

低温对苹果贮藏过程中H2O2水平的影响

在低温贮藏条件下，苹果虎皮病从１１－１２月间开始发生并迅速加重。在此之前，果皮中Ｈ２Ｏ２水平逐渐上升，１１－１２月达最大值。Ｈ２Ｏ２水平的变化与细胞中保护系统和木质素合成有关。与晚采果相比，早采果中ＳＯＤ和ＣＡＴ活性均高，低温下ＣＡＴ活性较ＳＯＤ下降为快，早采果尤为显著，因此果皮中Ｈ２Ｏ２水平也高。抗氧化剂二苯胺对ＳＯＤ和ＣＡＴ无影响，但显著抑制木质素合成，降低Ｈ２Ｏ２水平，减少发病率。     

自由基清除剂对几种蔬菜衰老种子活力的影响

用外源自由基清除剂ＳＢＮ（１、２ｍｍｏｌ／Ｌ）和ＧＳＨ（０．００１、０．００５ｋｇ／Ｌ）浸种西瓜、甜瓜和萝卜衰老种子能显著促进其萌发,而ＡｓＡ（５、１０、１５ｍｍｏｌ／Ｌ）浸种效果不明显,上述处理要不同程度地提高衰老种子中ＣＡＴ和ＳＯＤ活性,降低Ｏ２＾－产生速率,减轻膜脂过氧化作用。     

硒对棚室黄瓜生物抗氧化能力的影响

在节能温室栽培条件下,研究了硒对黄瓜叶片中谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）活性、膜脂过氧化产物丙二醛（ＭＤＡ）的积累及黄瓜产量的影响。结果表明,与对照相比,施用一定量的硒可使黄瓜叶片中ＧＳＨ－Ｐｓ活性提高３３．４１％－５８．５３％,Ｆ＝２１．６６＾＊＊;使ＭＤＡ含量降低１６．９３％－３１．８１％,Ｆ＝１０．９１＾＊;ＧＳＨ－Ｐｘ活性与ＭＤＡ含量间呈极显负相关,ｒ＝－０．８６５＾＊＊;产量提高１     

赤霉素对芹菜采后衰老的影响

芹菜在衰老过程中，叶绿素不断降解，过氧化物酶活性升高而ＳＯＤ活性逐渐降低，与此同时，膜脂质过氧化作用逐渐增强，表现为脂质过氧化产物──丙二醛不断积累，导致细胞膜透性逐渐增大。外源赤霉素（ＧＡ）处理可以明显抑制芹菜衰老过程中的脂质过氧化作用，延缓芹菜的衰老。，达极显著水平。图２各处理ＰＯ０、ＳＯＤ活性的变化（叶柄）在：ＳＯＤ活性是以初始值为１００的相对活性。２．４ＧＡ处理芹菜丙二醛（ＭＤＡ）含量的变化图３各处理叶柄ＭＤＡ含量的变化由图３可以看出，作为膜脂过氧化产物之一──丙二醛，在芹菜衰老过程中呈累积性上升，ＧＡ处理，可以极显著地（α＝０．０ｌ）抑制ＭＤＡ积累，２．５芹菜衰老过程中细胞膜透性的变化表２ＧＡ处理叶柄细胞膜透性的变化相对电导率％由表２的结果可以看出，随着实验期的延长，芹菜的细胞膜透性逐渐增大，ＧＡ处理，可显著地降低膜透性的变化，保护膜结构的完整性。３讨论与结论目前，关于植物衰老的研究表明，膜脂过氧化对植物的衰老具有促进与加强作用［４］。本试验的结果表明，芹菜衰老过程中，在叶绿素降解的同时，ＳＯＤ活性下降，脂质过氧化产物──ＭＤＡ积累，导致细胞内膜系统的连锁性破坏。并且越到后期这种破坏作用越为明显，     

温度预处理对柑橘果实活性氧代谢相关酶的影响

以尾张温州蜜柑（Ｃｉｔｒｕｓ　ｕｎｓｈｉｕ　Ｍａｒｃ．）和哈姆林甜橙（Ｃｉｔｒｕｓ　ｓｉｎｅｎｓｉｓ　Ｏｓｂｅｃｋ．）为试材，研究了不同温度预处理对果实呼吸速率、超氧化物歧化酶（ＳＯＤ）活性、过氧化氢酶（ＣＡＴ）活性、过氧化物酶（ＰＯＤ）活性、丙二醛（ＭＤＡ）含量、果皮相对电导率（ＲＥＣ）和木质素含量的影响。结果表明，２０℃预处理 ３ｄ的果实，在贮藏至 １００ ｄ时，呼吸速率、ＭＤＡ含量。果皮 ＲＥＣ均为最低。２０℃预处理果实在贮藏后期 ＳＯＤ与 ＣＡＴ能较好地协同作用清除 Ｏ２－·，果实受自由基伤害程度最小，果实衰老得以延缓。温度预处理引起的ＰＯＤ活性的上升可能与提高果皮木质素含量、加速受损伤油胞的迅速愈合有关，而贮藏后期 ＰＯＤ活性的上升可能与果实的衰老有关。     

水分胁迫条件下苹果幼苗叶绿体抗氧化代谢研究

以苹果属八棱海棠和平邑甜茶组培幼苗为试材，研究了不同浓度ＰＥＧ６０００溶液处理条件下幼苗叶绿Ｏ_２~－和Ｈ_２Ｏ_２代谢变化。结果表明，随着水分胁迫的加重，苹果属植物叶绿体光合放氧活性和ＰＳⅡ电子传递活性先上升而后下降；叶绿体Ｏ_２~－和Ｈ_２Ｏ_２产生速率持续上升；ＳＯＤ、ＣＡＴ、ＡｓＡ－ＰＯＤ、ＧＲ活性在轻度水分胁迫条件下显著上升，在重度水分胁迫条件下显著下降，脂质过氧化产物ＭＤＡ含量则呈相反的趋势；叶绿体ＡｓＡ和ＧＳＨ含量随水分胁迫而下降；叶绿体膜脂质组分随水分胁迫而出现饱和脂肪酸含量上升，不饱和脂肪酸含量下降，不饱和脂肪酸指数下降，类脂中饱和脂肪酸和不饱和脂肪酸的这种变化主要发生在ＭＧＤＧ、ＤＧＤＧ、ＳＬ和ＰＧ中。综合分析阐明了水分胁迫条件下苹果属植物叶绿体Ｏ_２~－和Ｈ_２Ｏ_２产生与清除的生理机理。种间各指标比较表明，水分胁迫条件下八棱海棠幼苗叶绿体比平邑甜茶具有较强的抗氧化能力。     

水分胁迫条件下苹果幼苗叶绿体抗氧化代谢研究

以苹果属八棱海棠和平邑甜茶组培幼苗继试材,研究了不同浓度ＰＥＧ６００溶液处理条件下幼苗叶绿体Ｏ２＾－和Ｈ２Ｏ２代谢变化。结果表明,随着水分胁迫的加重,苹果属植物叶绿体光合放氧活性和ＰＳⅡ电子传递活性先上升而后下降叶绍体Ｏ２＾－和Ｈ２Ｏ２产生速率特续上升;ＳＯＤ、ＣＡＴ、ＡｓＡＰＯＤ、ＧＲ活性在轻度水分胁迫条件下显著上升,在重庆水分胁迫条件下显著和,脂质过氧化产物ＭＤ芩是呈相反的趋势;叶绍体ＡｓＡ和     

芒果冷害对两种自由基清除剂的影响

紫花芒果在２℃中１５天完全冷害，冷害发生时，超氧物歧化酶（ＳＯＤ）活性略有上升后下降，过氧化氢酶（ＣＡＴ）活性持续下降，说明冷害可降低ＣＡＴ和ＳＯＤ活性，加强膜脂过氧化作用。非冷害情况下，紫花芒果在１０℃中贮藏２０天开始启动后熟；成熟过程中，ＳＯＤ和ＣＡＴ活性达高峰，说明果实启动成熟时生命活动大大加强。     

SO2对龙眼果实的氧化作用与衰老的影响

以‘石硖’龙眼（Ｄｉｍ ｏｃａｒｐｕｓｌｏｎｇａｎ Ｌｏｕｒ．ｃｖ．Ｓｈｉｘｉａ）为试材,研究了冷藏（４ ℃）条件下,适当的ＳＯ２ 熏蒸预处理对果实氧化作用与衰老的影响。结果表明：硫处理果实,呼吸速率比对照显著降低（Ｐ＜ ０．０１）,使果实受到不可逆抑制;果皮膜透性和丙二醛（ＭＤＡ）含量比对照明显增加（Ｐ＜ ０．０１）,超氧物歧化酶（ＳＯＤ）活性成倍提高,并出现新的ＳＯＤ同工酶带。贮藏效果表明：合理的ＳＯ２ 处理能够延缓果实的衰老进程,延长贮藏寿命     

Effects of radiation from 188Re on smooth muscle cell proliferation

AIM: Although endovascular radiotherapy inhibits neointimal hyperplasia, the exact alterations induced by β-particles irradiation remain to be elucidated. The objective of this study was to investigate the ability and the cellular mechanism of local β^-particles emission from ¹⁸⁸Re to inhibit vascular smooth muscle cells (SMCs). METHODS: The SMCs in vitro were irradiated by ¹⁸⁸Re with single doses of 2.6 Gy-25.8 Gy. The effects of β-particles on SMCs, such as effective irradiate doses, the period of inhibition for SMCs proliferation, the changes of cell proliferation rate and DNA synthesis rate, cell cycle progression and related gene expression, were investigated by cell count, [³H]-TdR incorporation, cell cycle progression analysis, cell viability and immunocytochemistry, respectivecy. RESULTS: β-particles irradiation with dose of 5.2 Gy could inhibit significantly SMCs proliferation. At dose of 20.6 Gy DNA synthesis inhibitory rate was 92%, SMCs proliferation rate was only 3%. Renoval of ¹⁸⁸Re did not abolish the inhibitory effects of β-particles on SMCs proliferation. The expression of P53 was up regulation and PCNA was down regulation after irradiation. CONCLUSION: β-particles from ¹⁸⁸ Re was significantly effective and permanent in inhibiting SMCs proliferation, and inhibitory effect was in dose-dependet manner ED50was 5 Gy, the best dose to inhibit SMCs proliferation was 20 Gy. β-particles irradiation induced SMCs to occur G₀/G₁ arrest, damaged the ability of SMCs reproliferation and led to cell clonogenic death. P53 and PCNA had regulatiory effects on SMCs proliferation after β-particles irradiation.     

Effect of L-Arg on plasma content of endothelin and expression of c-fos mRNA in the left ventricle of rats with renovascular hypertensive hypertrophy

AIM:To study the effect of L-Arg on plasma content of endothelin (ET) and the expression of proto-oncogene c-fos mRNA in the left ventricle of rats with renovascular hypertensive hypertrophy. METHODS: The level of c-fos mRNA were measured by in situ hybridization. The ET in plasma were measured by radioimmunoassay. RESULTS:After eight weeks of treatment with L-Arg, the expression of c-fos decreased markedly (P＜0.01). The ET content in plasma also decreased significantly by L-Arg(P＜0.01).CONCLUSION: Plasma ET content and the expression of c-fos in the left ventricle of rats with renovascular hypertensive hypertrophy could be decreased by L-Arg administration.     

多效唑对猕猴桃离体试管苗生长及内源激素的影响

多效唑（ＰＰ３３３）处理猕猴桃试管苗，降低了其生长强度；植株体内的ＧＡ３、ＩＡＡ和ＺＴ含量下降，ＡＢＡ的含量上升，乙烯释放率增加；并且能降低外源的ＧＡ３和ＩＡＡ促进生长的作用，而外源的ＧＡ３和ＩＡＡ又能不同程度地逆转多效唑的抑制作用，使植株恢复生长。     

Proteomic analysis between pathological scars and normal skin

AIM: To investigate and screen the sensitive proteins in the formation mechanism of pathological scars by comparing the results of differential proteomic analysis between pathological scars and normal skin.METHODS: Two-dimensional gel electrophoresis was used to detect the protein expression profiles in 8 keloid patients, 8 hypertrophic scar patients and 3 matched normal skin patients.The proteins that showed differential expression of over 4-fold change were cut and analyzed by MALDI-TOF/TOF mass spectrometry.RESULTS: A two-dimensional protein profiling comparison between pathological scars and normal skin was successfully established.On average, 2 978 spots in keloid, 2 975 spots in hypertrophic scar and 3 053 spots in normal skin were identified using gel analysis software.Compared with normal skin, there were totally 36 differentially-expressed proteins in keloid and hypertrophic scar identified from the spots of over 4-fold change, including 16 proteins in both keloid and hypertrophic scar (8 up-regulated and 8 down-regulated), 11 only in keloid (9 up-regulated and 2 down-regulated) and 9 only in hypertrophic scar (4 up-regulated and 5 down-regulated).CONCLUSION: Proteomic analysis can identify the proteins with variance of pathological scars versus normal skin, thus providing probable new clues to reveal the formation mechanism of pathological scars.     

Compositional and Functional Properties of Saskatoon Berry and Blueberry

Abstract

Saskatoon berry (Amelanchier alnifolia Nutt., Rosaceae) and blueberry (Vaccinium corymbosum L., Ericaceae) are substantially equivalent in all characteristics that are important to the consumer, including fruit color, shape, size, nutrition, texture, and uses. In addition, both fruits are native to North America and they have practically identical historical uses and known health benefits. Their composition, processing, nutritional value and metabolism, intended uses, and levels of undesirable substances are compared.     

Cryopreservation of shoot apices of hawthorn in vitro cultures originating from East Asia

The objective of this study was to establish a cryopreservation protocol for hawthorn shoot apices (Crataegus pinnatifida Bge.). Cryopreservation was carried out via encapsulation–dehydration, vitrification, and encapsulation–vitrification on shoot apices excised from in vitro cultures. We began by showing that cold-acclimation enhanced the regrowth of cryopreserved apices from 10.0 to 65.5% in encapsulation–dehydration. We then decided that the encapsulation–dehydration method was an optimal cryopreservation method for hawthorn shoot apices in terms of its high recovery after cryopreservation as well as its ease of use compared with vitrification and encapsulation–vitrification. In encapsulation–dehydration, the protocol leading to optimal regrowth was as follows: after cold-acclimation at 5 °C in the dark for 2 weeks, excised shoot tips were pretreated for 24 h at 25 °C on hormone-free Murashige and Skoog [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tobacco tissue culture. Physiol. Plant. 15, 473–497] (MS) basal medium with 0.4 mol/L sucrose, then encapsulated and precultured in liquid MS medium with 0.8 mol/L sucrose for 16 h at 25 °C. Precultured beads were dehydrated for 6 h at 25 °C in the dessicator containing 50 g silica gel to a moisture content of 15.3% (fresh-weight basis) before cryostorage for 1 h. In addition, we examined the effect of adding glycerol to both the alginate beads and loading solution to enhance regrowth after cryopreservation in encapsulation–dehydration. In the present study, it was shown that adding 0.5 mol/L glycerol resulted in high regrowth percentages (82.5–90.0%) in four Crataegus species.     

Coupling past management practice and historic landscape change on John F. Kennedy Space Center,Florida

Historic landcover dynamics in a scrubby flatwoods (Tel-4) and scrub landscape (Happy Creek) on John F. Kennedy Space Center were measured using aerial images from 1943, 1951, 1958, 1969, 1979, and 1989. Landcover categories were mapped, digitized, geometrically registered, and overlaid in ARC/INFO. Both study sites have been influenced by various land use histories, including periods of range management, fire suppression, and fire management. Several analyses were performed to help understand the effects of past land management on the amount and spatial distribution of landcover within the study sites. A chi-squared analysis showed a significant difference between the frequency of landcover occurrence and management period. Markov chain models were used to project observed changes over a 100-year period; these showed current management practices being effective at Tel-4 (restoring historic landscape structure) and much less effective at Happy Creek. Documenting impacts of past management regimes on landcover has provided important insight into current landscape composition and will provide the basis for improving land management on Kennedy Space Center and elsewhere.     

XBP-01 accelerated apoptosis induced by oxidized low density lipoprotein in vascular smooth muscle cells

AIM: Previous studies performed with XBP-01 in vitro indicated that XBP-01 could inhibit vascular smooth muscle cells from being transformed into foam cell and could eliminate the atherosclerotic plaque in C57BL/6J mouse. This experiment is to investigate its mechanism of eliminating plaques in vitro. METHODS: The cultured porcine artery smooth muscle cells incubated with XBP-01 of 0.1 mg/L for 24 h after preincubated with oxidized low density lipoprotein of 15 mg/L for 72 h in vitro. The samples were analyzed by fluorescence microscope, confocal microscope system and flow cytometry. RESULTS: Apoptosis was triggered by being incubated with oxidized low density lipoprotein and this process was accelerated additionally by being incubated with XBP-01. CONCLUSION: XBP-01 can be effective in eliminating atherosclerotic plaque by accelerating the process in which oxidized low density lipoprotein induced smooth muscle cell apoptosis.     

Metallothionein inhibits homocysteine-induced proliferation of rat vascular smooth muscle cells

AIM:To investigate the effect of metallothionein(MT) on proliferation of rat vascular smooth muscle cells (VSMCs) stimulated by homocysteine and its mechanism. METHODS:VSMCs proliferation was measured by [³-H]-TdR incorporation, mitogen-activated protein kinase(MAPK)activity were determined by immunoprecipitation method, the intracellular contents of MT and malondialdehyde (MDA)were assayed by -hemoglobin saturation method and TBA reaction, respectively, and lactate dehydrogenase (LDH) leakage was measured by NADH oxidation. RESULTS:Hcy(10^-6-10^-4 mmol/L) stimulated [³-H]-TdR incorporation by the VSMCs in a concentration-dependent manner. Compared with control, [³-H]-TdR incorporation in VSMCs treated with 0.1 mmol/L Hcy was increased by 4.2 fold (P＜0.01). Meanwhile, Hcy enhanced MAPK activity, MDA formation and LDH release (P＜0.01)in a concentration-dependent manner. Treatment of VSMCs with MT alone did not change above parameters, compared with control. However, MT (10^-6-10^-4 mol/L)attenuated significantly Hcy-stimulated proliferation of VSMCs (P＜0.01)in a concentration-dependent manner. And MT inhibited obviously Hcy-induced activation of MAPK activity, MDA formation and LDH release. Preincubation of VSMCs with 0.5 mmol/L ZnCl₂ for 6 h induced an increase cellular MT content by 5.7-fold (P＜0.01). The MT-overexpressed VSMCs resisted Hcy-stimulating action on MAPK activity, MDA formation and LDH leakage (P＜0.01). CONCLUSION:These results show that MT has an inhibitory effect on Hcy-induced VSMCs proliferation, and that MT could inhibit Hcy-stimulated MAPK activity and lipid peroxidation.     

The effect of exposure on landscape scale soil surface temperatures and species distribution models

Species distribution models (SDMs) often use elevation as a surrogate for temperature or utilise elevation sensitive interpolations from weather stations. These methods may be unsuitable at the landscape scale, especially where there are sparse weather stations, dramatic variations in exposure or low elevational ranges. The goal of this study was to determine whether radiation, moisture or a novel estimate of exposure could improve temperature estimates and SDMs for vegetation on the Illawarra Escarpment, near Sydney, Australia. Forty temperature sensors were placed on the soil surface of an approximately 12,000 ha study site between November 2004 and August 2006. Linear regression was used to determine the relationship with environmental factors. Elevation was correlated more with moderate temperatures (winter maximums, summer minimums, spring and autumn averages) than extreme temperatures (summer maximums, winter minimums). The correlation (r ²) between temperature and environmental factors was improved by up to 0.38 by incorporating exposure, moisture and radiation in the regressions. Summer maximums and winter minimums were predominately determined by exposure to the NW and coastal influences respectively, while exposure to the NE and SW was important during other seasons. These directions correspond with the winds that are most influential in the study area. The improved temperature estimates were used in Generalised Additive Models for 37 plant species. The deviance explained by most models was increased relative to elevation, especially for moist rainforest species. It was concluded that improving the accuracy of seasonal temperature estimates could improve our ability to explain the patchy distribution of many species. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.