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目的:利用体外培养的乳鼠心肌细胞,观测高浓度胰岛素和高浓度葡萄糖作用下对去甲肾上腺素诱导的心肌细胞肥大的影响,并探讨其可能作用机制.方法:以培养的乳鼠心肌细胞为模型分组给药后,用显微镜目镜计数心肌细胞搏动的频率;用Lowrys法测心肌细胞的蛋白质含量;用消化分离法,利用计算机图象分析系统测心肌细胞的体积;用[3H]leucine标记法测定心肌细胞蛋白的合成.结果:与对照组相比,去甲肾上腺素(NE)组、高糖组、高胰岛素组心肌细胞蛋白含量、体积、蛋白合成均有明显增加,而与高糖加NE组和高糖高胰岛素组相比较,高糖高胰岛素加NE组心肌细胞蛋白含量、体积、蛋白合成增加则更为显著.结论:单纯高浓度胰岛素培养可促进心肌细胞肥大,同时用高糖高胰岛素联合培养,可使去甲肾上腺素诱导的心肌细胞肥大作用进一步增强.  相似文献   

3.
In the present study we investigated a potential mechanism by which high sugar (HS) and high fat (HF) diets could affect acetylcholinesterase (AChE) activity. The treatment with HS and HF diet was done for six months on male and female rats. The results showed decreased hippocampal AChE activity in male and females receiving HS and HF diets (HS 24% and 36%; HF 38% and 32%, males and females, respectively; P < 0.05). The activity in the cerebral cortex was reduced in males (49 and 40%) and females (19 and 17%) (P < 0.05) on HS and HF diets, respectively. In the hypothalamus AChE activity was decreased on HS diet in males (46%) and female (25%) (P < 0.05) and also on HF diet in males (34%) and females (21%) (P < 0.05). However, in the cerebellum no changes in AChE activity were observed. These results indicate that HS and HF diets produced mainly inhibition in acetylcholine degradation. It probably indicates a chronic alteration induced by these diets on the cholinergic system.  相似文献   

4.
C3 photosynthesis is often limited by CO2 diffusivity or stomatal (gs) and mesophyll (gm) conductances. To characterize effects of stomatal closure induced by either high CO2 or abscisic acid (ABA) application on gm, we examined gs and gm in the wild type (Col‐0) and ost1 and slac1‐2 mutants of Arabidopsis thaliana grown at 390 or 780 μmol mol?1 CO2. Stomata of these mutants were reported to be insensitive to both high CO2 and ABA. When the ambient CO2 increased instantaneously, gm decreased in all these plants, whereas gs in ost1 and slac1‐2 was unchanged. Therefore, the decrease in gm in response to high CO2 occurred irrespective of the responses of gs. gm was mainly determined by the instantaneous CO2 concentration during the measurement and not markedly by the CO2 concentration during the growth. Exogenous application of ABA to Col‐0 caused the decrease in the intercellular CO2 concentration (Ci). With the decrease in Ci, gm did not increase but decreased, indicating that the response of gm to CO2 and that to ABA are differently regulated and that ABA content in the leaves plays an important role in the regulation of gm.  相似文献   

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Human plasma HDLs are classified on the basis of apolipoprotein composition into those that contain apolipoprotein A-I (apoA-I) without apoA-II [(A-I)HDL] and those containing apoA-I and apoA-II [(A-I/A-II)HDL]. ApoA-I enters the plasma as a component of discoidal particles, which are remodeled into spherical (A-I)HDL by LCAT. ApoA-II is secreted into the plasma either in the lipid-free form or as a component of discoidal high density lipoproteins containing apoA-II without apoA-I [(A-II)HDL]. As discoidal (A-II)HDL are poor substrates for LCAT, they are not converted into spherical (A-II)HDL. This study investigates the fate of apoA-II when it enters the plasma. Lipid-free apoA-II and apoA-II-containing discoidal reconstituted HDL [(A-II)rHDL] were injected intravenously into New Zealand White rabbits, a species that is deficient in apoA-II. In both cases, the apoA-II was rapidly and quantitatively incorporated into spherical (A-I)HDL to form spherical (A-I/A-II)HDL. These particles were comparable in size and composition to the (A-I/A-II)HDL in human plasma. Injection of lipid-free apoA-II and discoidal (A-II)rHDL was also accompanied by triglyceride enrichment of the endogenous (A-I)HDL and VLDL as well as the newly formed (A-I/A-II)HDL. We conclude that, irrespective of the form in which apoA-II enters the plasma, it is rapidly incorporated into spherical HDLs that also contain apoA-I to form (A-I/A-II)HDL.  相似文献   

6.
银耳子实体多糖高温高压提取工艺研究   总被引:3,自引:0,他引:3  
通过对银耳子实体多糖高温高压提取工艺中,提取温度、料液比、提取时间,提取次数等影响因素的实验分析,确定银耳子实体多糖高温高压提取的最佳条件为:提取温度110℃(对应压力0.04 MPa);料液比为1∶70;提取时间为2 h;提取次数为2次,在此条件下,银耳子实体多糖提取率可达36.5%。  相似文献   

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康脂口服液药效学研究   总被引:1,自引:0,他引:1  
通过体内外血栓形成实验证明康脂口服液可明显延长大鼠血栓形成时间,减少血栓长度和重量.对高血脂大、小鼠血总脂、总胆固醇、甘油三酯均有不同程度降低作用,对高血脂大鼠低密度脂蛋白增高有明显抑制作用.此外可增加麻醉犬脑血流量,降低脑血管阻力,减轻脑缺血后脑水肿,降低血粘度,改善微循环,降低血小板聚集率.  相似文献   

8.
Apolipoprotein M (apoM) is a novel apolipoprotein that is reportedly necessary for preβ HDL formation; however, its detailed function remains unknown. We investigated the biogenesis and properties of apoM and its effects on the initial steps of nascent preβ HDL assembly by ABCA1 in HEK293 cells. Transiently transfected apoM was localized primarily in the endomembrane compartment. Pulse-chase analyses demonstrated that apoM is inefficiently secreted, relative to human serum albumin, and that ∼50% remains membrane-associated after extraction with sodium carbonate, pH 11.5. To investigate the role of apoM in nascent preβ HDL formation, ABCA1-expressing or control cells, transfected with empty vector, apoM, or C-terminal epitope-tagged apoM (apoM-C-FLAG), were incubated with 125I-apoA-I for 24 h. Conditioned media were harvested and fractionated by fast-protein liquid chromatography (FPLC) to monitor HDL particle size. Preβ HDL particles were formed effectively in the absence of apoM expression; however, increased apoM expression stimulated the formation of larger-sized nascent preβ HDLs. Immunoprecipitation with anti-apoA-I antibody followed by apoM Western blot analysis revealed that little secreted apoM was physically associated with preβ HDL. Our results suggest that apoM is an atypical secretory protein that is not necessary for ABCA1-dependent preβ HDL formation but does stimulate the formation of larger-sized preβ HDL. We propose that apoM may function catalytically at an intracellular site to transfer lipid onto preβ HDL during or after their formation by ABCA1.  相似文献   

9.
Small single‐celled Chaetoceros sp. are often widely distributed, but frequently overlooked. An estuarine diatom with an extremely high growth potential under optimal conditions was isolated from the Shinkawa‐Kasugagawa estuary in the eastern part of the Seto Inland Sea, western Japan. It was identified as Chaetoceros salsugineum based on morphological observations. This strain had a specific growth rate of 0.54 h?1 at 30°C under 700 μmol · m?2 · s?1 (about 30% of natural maximal summer light) with a 14:10 L:D cycle; there was little growth in the dark. However, under continuous light it grew at only 0.35 h?1 or a daily specific growth rate of 8.4 d?1. In addition, cell density, chlorophyll a, and particulate organic carbon concentrations increased by about 1000 times in 24 h at 30°C under 700 μmol · m?2 · s?1 with a 14:10 L:D cycle, showing a growth rate of close to 7 d?1. This very rapid growth rate may be the result of adaptation to this estuarine environment with high light and temperature. Thus, C. salsugineum can be an important primary producer in this estuary in summer and also an important organism for further physiological and genetic research.  相似文献   

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高温高湿胁迫及恢复对番茄快速荧光诱导动力学的影响   总被引:1,自引:0,他引:1  
为了研究高温高湿复合胁迫对番茄的影响,以番茄品种“金冠五号”(Jinguan 5)为试材,于2018年6-9月在南京信息工程大学农业气象试验室进行温度、相对湿度与处理天数三因素正交试验,温度设置4个水平(昼温/夜温),即32℃/22 ℃、35℃/25℃、38℃/28 ℃、41℃/31℃,空气相对湿度设置3个水平为50%±5%、70%±5%、90%±5%,4个持续时间(3、6、9、12 d),以28℃/18℃、50%~55%环境下处理的番茄幼苗为对照(CK),测定不同处理下番茄叶片光合参数和快速荧光诱导动力学参数.结果表明:在日最高32~41℃范围内,随着温度升高,番茄光饱和点(LSP)、表观量子效率(AQE)、最大净光合速率(Pmax)、最大光化学效率(Fv/Fm)、光合性能指数(PIabs)、综合性能指数(PItotal)、用于电子传递的量子产额(φEo)、用于还原PSI受体侧末端电子受体的量子产额(φRo)、用于电子传递的光能(ET0/CSm)和有活性的反应中心数量(RC/CSm)均有所降低,快速叶绿素荧光诱导曲线发生变化,J、I、P相降低,且AK小于0.在高温环境下,70%湿度处理的LSP、AQE、Pmax、Fv/Fm、PIabs PItotal、φEo、φRo、ETo/CSm、RC/CSm等指标显著高于50%和90%湿度处理.不同天数处理和恢复期间各指标无显著性差异.研究表明:高温胁迫破坏了番茄幼苗光系统的结构和功能,在超过日最高35℃的环境中,适当增加空气相对湿度至70%,可稳定光合反应中心,缓解高温胁迫对植物光合系统的伤害.  相似文献   

11.
王浩  王明  梁婷  姚玉新  杜远鹏  高振 《植物学报》2022,57(2):209-216
为探究气温和根区温度对葡萄(Vitis vinifera)叶片光合荧光特性的影响,以一年生巨峰葡萄为试材,设置对照、高气温、高根区温度和两者交叉作用共4组处理。结果表明,相较于对照和高气温,高根区温度以及交叉处理叶片最大光化学效率(Fv/Fm)降低更明显;与对照相比,高根区温度以及高气温与高根区温度交叉处理下光系统II (PSII)实际光化学效率Y(II)显著降低,非调节能量耗散的量子产量Y(NPQ)及QA氧化还原状态(1–qP)值显著上升。同时,高根区温度以及高气温与高根区温度交叉处理显著增加了J点的可变荧光(Vj),而用于电子传递的量子产额(φEo)及性能指数(PIABS)显著降低。此外,高根区温度以及高气温与高根区温度交叉处理下单位面积有活性的反应中心数目(RC/CSm)也显著下降,K点相对可变荧光(Wk)明显上升。综上所述,高根区温度是高气温与根区高温交叉胁迫的主导因子, PSII受体侧是主要的伤害位点,高气温加剧了高根区温度对PSII造成的伤害。  相似文献   

12.
Herein, a new P2‐type layered oxide is proposed as an outstanding intercalation cathode material for high energy density sodium‐ion batteries (SIBs). On the basis of the stoichiometry of sodium and transition metals, the P2‐type Na0.55[Ni0.1Fe0.1Mn0.8]O2 cathode is synthesized without impurities phase by partially substituting Ni and Fe into the Mn sites. The partial substitution results in a smoothing of the electrochemical charge/discharge profiles and thus greatly improves the battery performance. The P2‐type Na0.55[Ni0.1Fe0.1Mn0.8]O2 cathode delivers an extremely high discharge capacity of 221.5 mAh g?1 with a high average potential of ≈2.9 V (vs Na/Na+) for SIBs. In addition, the fast Na‐ion transport in the P2‐type Na0.55[Ni0.1Fe0.1Mn0.8]O2 cathode structure enables good power capability with an extremely high current density of 2400 mA g?1 (full charge/discharge in 12 min) and long‐term cycling stability with ≈80% capacity retention after 500 cycles at 600 mA g?1. A combination of electrochemical profiles, in operando synchrotron X‐ray diffraction analysis, and first‐principles calculations are used to understand the overall Na storage mechanism of P2‐type Na0.55[Ni0.1Fe0.1Mn0.8]O2.  相似文献   

13.
Achieving high areal capacity is a challenge for current lithium‐ion batteries (LIBs). To address this issue, nickel foam (NF), as a free‐standing skeleton suffers from long‐term poor anchor ability for active materials, resulting in detachment from conductive substrates. In addition, the weighty NF damages the overall energy density of the electrode. Herein, an in situ fabrication of interlayer strategy is proposed to effectively address these issues through constructing layer‐by‐layer a 3D structure composed of an inner conductive framework, medial NiO layer, and outer few‐layer NiO nanoflowers in turn (NiO@NiO/NF). The interlayer derived from partial oxidation of NF not only reinforces the attachment of the active layer on NF but also contributes capacity to the whole electrode, leading to excellent stability and areal capacity. When used as the anode of LIBs, ultrahigh reversible capacity of 1.98 mAh cm?2 is delivered at 1.20 mA cm?2. The electrode still maintains good integrity and flexibility after 1000 cycles, showing good structure stability. Compared with previous reports, NiO@NiO/NF is one of the most outstanding NiO‐based electrodes. This work proposes a feasible strategy to enhance the capacity and stability of self‐supporting electrodes, and opens a new avenue for high‐areal‐capacity anode of LIBs.  相似文献   

14.
Lithium–sulfur (Li–S) batteries, due to the high theoretical energy density, are regarded as one of the most promising candidates for breaking the limitations of energy‐storage system based on Li‐ion batteries. Tremendous efforts have been made to meet the challenge of high‐performance Li–S batteries, in which a sulfur loading of above 5 mg cm?2 delivers an areal capacity higher than 5 mAh cm?2 without compromising specific capacity and cycling stability for practical applications. However, serious problems have been exposed during the scaling up of the sulfur loading. In this review, based on mechanistic insights into structural configuration, catalytic conversion, and interfacial engineering, the problems and corresponding strategies in the development of high‐loading Li–S batteries are highlighted and discussed, aiming at bridging the gap between fundamental research and practical cell‐level designs. Stemming from the current achievements, future directions targeting the high‐energy‐density Li–S batteries for commercialization are proposed.  相似文献   

15.
Sodium ion batteries have attracted much attention in recent years, due to the higher abundance and lower cost of sodium, as an alternative to lithium ion batteries. However, a major challenge is their lower energy density. In this work, we report a novel multi‐electron cathode material, KVOPO4, for sodium ion batteries. Due to the unique polyhedral framework, the V3+ ? V4+ ? V5+ redox couple was for the first time fully activated by sodium ions in a vanadyl phosphate phase. The KVOPO4 based cathode delivered reversible multiple sodium (i.e. maximum 1.66 Na+ per formula unit) storage capability, which leads to a high specific capacity of 235 Ah kg?1. Combining an average voltage of 2.56 V vs. Na/Na+, a high practical energy density of over 600 Wh kg?1 was achieved, the highest yet reported for any sodium cathode material. The cathode exhibits a very small volume change upon cycling (1.4% for 0.64 sodium and 8.0% for 1.66 sodium ions). Density functional theory (DFT) calculations indicate that the KVOPO4 framework is a 3D ionic conductor with a reasonably, low Na+ migration energy barrier of ≈450 meV, in line with the good rate capability obtained.  相似文献   

16.
目的:观察高糖高脂膳食对大鼠肝组织碳水化合物反应元件结合蛋白(ChREBP)表达的影响。方法:16只雄性SD大鼠随机分为2组,对照组给予普通饲料,高糖高脂组给予高糖高脂饲料。6周后,检测血脂和肝组织中ChREBP表达水平。结果:高糖高脂膳食组ChREBPmRNA表达水平、血总甘油三酯、总胆固醇和高密度脂蛋白浓度均显著高于对照组(P〈0.05);血低密度脂蛋白明显低于对照组(P〈0.05)。结论:高搪高脂膳食能引起肝脏组织中碳水化合物反应元件结合蛋白表达增加。  相似文献   

17.
人类基因组全序列的精细图已完成,当前生命科学面临的重要任务就是如何将基因组序列信息转化为基因的功能信息,了解生命活动的分子机理,改善人类健康,为生物技术发展提供动力 . 在一系列功能基因组研究新技术中,高通量 (high-throughput) 和高内涵 (high-content) 的细胞筛选技术平台已经显示出巨大潜力,发挥着越来越重要的作用 . 通过在体外培养的哺乳动物细胞中基因过表达或抑制基因表达,分析所产生信号传导通路和 / 或细胞表型改变,可以直接发现基因功能 . 近年来一些技术上的进展,使细胞筛选平台具有微量、自动、高效、高通量,以及可以系统研究的特点,已经成为功能基因组研究的核心方法之一 . 近 2~3 年来已经出现一批成功应用细胞筛选平台进行大规模功能基因组研究的报道 . 我国在这一领域的研究也开始起步,将对我国生物技术的源头创新研究产生深远的影响 .  相似文献   

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啤酒酵母对高浓麦汁的响应   总被引:2,自引:0,他引:2  
综述了啤科高浓酿造中酵母对麦汁浓度、糖的种类、金属离子、应力、氧等因素的响应。  相似文献   

20.
Strains of Zymomonas mobilis grown in media containing either glucose or sucrose were assessed for the production of hydrogen sulphide (H2S). In a liquid medium with low glucose concentration (20 g l?1) only a proportion of the strains tested formed H2S, but in medium containing a higher glucose concentration (100 g l?1) all the strains tested produced H2S. Four Z. mobilis strains were assayed quantitatively for H2S production and strain ZM4 was found to produce the most H2S in glucose medium. The amount of yeast extract and glucose, and the type of sugar used in the medium affected the amount of H2S formed by strain ZM4. A mutant, designated ZM4701, of strain ZM4 was isolated which did not produce any detectable H2S in liquid medium containing yeast extract plus either glucose or sucrose. The nutritional requirements of ZM4701 were investigated.  相似文献   

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