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21.
电压激活的钾通道阻断剂抑制山莨菪碱松弛去甲肾上腺素预收缩的兔主动脉平滑肌 总被引:11,自引:1,他引:11
研究显示,山莨菪碱预处理不改变高钾引起的兔主动脉环收缩,但可明显减弱去甲肾上腺素(noradrenaline,NA)、组织胺或5-羟色胺引起的收缩,且其减弱作用不受去除血管内皮影响。本实验观察了几种钾通道阻断剂对山良菪碱松弛:NA预收缩的兔主动脉环的影响。结果表明,1、3、10μmol/L山莨菪碱作用8min,可使0.01μmol/L NA预收缩的兔主动脉环松弛(P<O.01)。10mmol/L,CsCl、1mmol/L 4-氨基吡啶、10μmol/L BaCl2、10μmol/L格列本脲、3μmol/L charybdotoxin和3μmol/L蜂毒明从分别与0.0lμmol/L NA同时加入,可增强后者收缩兔主动脉环的作用(P<0.01)。10、30mmol/L CsCl或10、30mmol/L 4-氨基吡啶存在时,10μmol/L山茛菪碱对NA预收缩的兔主动脉环的松弛作用减弱,松弛率与对照组比较分别有极显著差异(P<0.01);10、30μmol/L BaCl2,10、30μmol/L格列本脲,3μmol/L charybdotoxin或3μmol/L蜂毒明肽存在时,山莨菪碱对NA预收缩的兔主动脉环的松弛作用不受影响(P>O.05)。本研究表明,电压激活的钾通道阻断剂抑制山莨菪碱松弛NA预收缩的兔主动脉平滑肌,初步提示血管平滑肌细胞膜上电压激活的钾通道参与山莨菪碱扩血管作用。 相似文献
22.
Petia Simeonova Nikolova Christian Zang Hans Pretzsch 《Trees - Structure and Function》2011,25(5):859-872
We show the potential of a new method combining tree-ring analyses on stems and on coarse roots of individual trees in order
to advance the understanding of growth dynamics in forest trees. To this end, we studied the root–shoot allometry of trees
and its dependence on site conditions. Along a gradient in water supply in Southern Germany from dry to moist sites we selected
43 Norway spruce trees (Picea abies [L.] H. Karst.) aged 65–100 years. Increment cores were taken from stem and main roots revealing aboveground and belowground
growth course over the last 34 years. Annual growth rates in roots and stems and their allometric relationships were applied
as surrogate variables for tree resource allocation to aboveground and belowground organs. The mean sensitivities of both
stem and root chronologies were found to be site-specific, and increased from the moist through the dry sites. No temporal
offset between aboveground and belowground growth reactions to climate conditions was found in Norway spruce at any of the
sites. These results suggest that the root–shoot allometry depends on the specific site conditions only at the driest site,
following the optimal biomass partitioning theory (the more restricted the water supply, the more organic matter allocation
into the belowground organs). 相似文献
23.
Manjeshwar S Lerner MR Zang XP Branam DE Pento JT Lane MM Lightfoot SA Brackett DJ Jupe ER 《Journal of molecular histology》2004,35(6):639-646
The prohibitin 3 untranslated region (3UTR) belongs to a novel class of non-coding regulatory RNAs. It arrests cell cycle progression by blocking G1-S transition in breast and other cancers. Our previous studies comparing MCF7 derived clones constitutively expressing a common allelic form of prohibitin RNA (UTR/C) to various controls demonstrated that it functions as a tumor suppressor. Here, we further characterized the morphology and motility of these transgenic breast cancer cells when grown in cell culture and on nude mice. In contrast to empty vector (EV) cells, UTR/C cells were observed to grow in an organized manner with more cell-cell contact and differentiate into structures with a duct-like appearance. Computer assisted cytometry to evaluate differences in nuclear morphology was performed on UTR/C and EV tissues from nude mice. Receiver operator curve areas generated using a logistic regression model were 0.8, indicating the ability to quantitatively distinguish UTR/C from EV tissues. Keratinocyte growth factor-induced motility experiments showed that migration of UTR/C cells was significantly reduced (80–90%) compared to EV cells. Together, these data indicate that this novel 3UTR influences not only the tumorigenic phenotype but also may play a role in differentiation and migration of breast cancer cells. 相似文献
24.
In this paper, a kind of Typhaceae plant species, Typha angustifolia L, with a high tolerance to Cr is described. Experiments were carried out to examine its ability to tolerant Cr and its physiological response. The results showed that there was no difference in growth, plant height, and biomass response to external Cr (VI) between the plants exposed to 100 microM Cr (VI) and control (0 microM), while increasing Cr levels to 200-800 microM induced a significant decrease in plant height and biomass, but no significant injury was detected, even for the plants exposed to 800 microM Cr. Chromium induced significant increases in superoxide dismutase (SOD) and peroxidase (POD) activities. Meanwhile, a significantly positive correlation was found between Cr and Mn or Cu in leaves and roots, respectively. The Cr tolerance of the plant appeared to be associated with the enhancement of SOD and POD activities and the improvement in uptake and translocation of the essential microelements. 相似文献
25.
Jun-Jie Zhang Bing-Zhong Ren Xiao-Hua Yuan Lian-Sheng Zang Chang-Chun Ruan Guang-Zhi Sun Xi-Wen Shao 《BioControl》2014,59(2):159-166
The striped stem borer, Chilo suppressalis (Walker), is one of the most economically important rice pests worldwide. However, biological control of this pest using natural-enemy insects has been rarely documented to date. With the objective of screening suitable candidate species for controlling the striped stem borer, we investigated the effect of the age of host eggs on the host selection and suitability by four indigenous Trichogramma species on their native host, C. suppressalis. The results indicated that the differently aged eggs of C. suppressalis were all accepted by T. japonicum, T. dendrolimi and T. chilonis, and there was a clear tendency to parasitize older eggs less under no-choice and choice conditions. The number of parasitized host eggs by T. ostriniae also decreased with the increasing host age in the no-choice test, but more 2-day-old host eggs were parasitized in the choice test. When 0-, 2-day-old eggs were offered, T. dendrolimi, T. japonicum and T. chilonis exhibited similar parasitism ability, whereas T. ostriniae appeared to have a stronger ability to attack the older host eggs (4-day-old). Trichogramma japonicum developed and emerged on parasitized C. suppressalis eggs of all ages tested, while showing a better adaptation to younger host eggs with significantly faster developmental time, higher survival and more female progeny on 0-day-old eggs. No adults for each of the other three Trichogramma species emerged from parasitized 4-day-old host eggs, and they had similar developmental time, survival and female progeny on parasitized 0-, 2-day-old host eggs with an exception of female progeny for T. chilonis. On 0-day-old host eggs, T. japonicum developed faster and T. ostriniae had lower progeny survival than the other three Trichogramma species evaluated, respectively. The current study provides useful information to select suitable Trichogramma species for controlling the striped stem borer, C. suppressalis. 相似文献
26.
为了了解我国两栖动物受威胁现状和致危因素, 进而制定相关的保护措施和开展国际合作, 本文依据中国两栖动物野生种群与生境现状, 利用《IUCN物种红色名录濒危等级和标准》(3.1版)和《IUCN物种红色名录标准在国家或地区的应用指南》(4.0版), 对中国已知的408种两栖动物的濒危状况进行了评估, 并编制了《中国两栖动物红色名录》。评估结果表明: 中国两栖动物有1种灭绝, 1种区域灭绝, 受威胁的两栖动物共计176种, 占评估物种总数的43.1%, 明显高于《IUCN濒危物种红色名录》(2015)的物种受威胁率(30.8%)。中国两栖动物特有种272种, 其中48.9%属于受威胁物种。中国两栖动物受威胁比例最高的目是有尾目(63.4%), 明显高于无尾目(39.0%); 受威胁比例最高的科是隐鳃鲵科(Cryptobranchidae) (仅有1种, 100%受威胁), 小鲵科(Hynobiidae) (86.7%)和叉舌蛙科(Dicroglossidae) (78.1%)。有11个省区的受威胁物种数占本省区两栖动物物种总数的30%及以上, 前3位分别是四川(40.8%)、广西(39.2%)和云南(37%)。中国大多数两栖动物物种分布在西南山地和华南地区, 以海拔2,000 m以下区域为主。栖息地退化或丧失、捕捉、环境污染列受威胁两栖动物致危因子的前3位。鉴于中国两栖动物区系的复杂性和独特性, 进一步加强两栖动物资源调查、种群和生境监测及相关科学研究, 仍是今后一段时期开展两栖动物多样性保护和濒危物种拯救行动的关键性基础工作。 相似文献
27.
Weiguo Wang Zhengguang Wang Shijie Chen Xiaofang Zang Jinglei Miao 《Journal of cellular biochemistry》2019,120(2):1763-1772
So far, microRNA has attracted plenty of interest due to its role in tumorigenesis. Reportedly, miR-181b may be involved in the tumorigenesis of osteosarcoma (OS). In the current study, we attempted to investigate the detailed function and mechanism of miR-181b in OS carcinogenesis. Herein, miR-181a, miR-181b, miR-181c, and miR-181d expressions in OS tissues were higher than that in nontumor tissue samples as examined real-time polymerase chain reaction. Via direct targeting, miR-181b negatively regulated the expression of phosphatase and tensin homolog (PTEN), a well-known tumor suppressor. Furthermore, a small interfering RNA strategy was used to find that interleukin (IL)-1B and nuclear factor-κB (NF-κB) regulate miR-181b and PTEN expression. Consequently, the repression of PTEN by miR-181b promotes OS cell proliferation. In summary, our data support a critical role for NF-κB-dependent upregulation of miR-181b, which further inhibited PTEN expression and promoted the cell proliferation of OS cell lines. The above findings represent a new pathway for the repression of PTEN and the promotion of cell proliferation upon IL-1β induction. 相似文献
28.
Si Zhang Zhongnan Yin Fei-Fei Dai Hao Wang Meng-Jiao Zhou Ming-Hui Yang Shu-Feng Zhang Zhi-Feng Fu Ying-Wu Mei Ming-Xi Zang Lixiang Xue 《Journal of cellular physiology》2019,234(8):13252-13262
Although cardiac hypertrophy is widely recognized as a risk factor that leads to cardiac dysfunction and, ultimately, heart failure, the complex mechanisms underlying cardiac hypertrophy remain incompletely characterized. The nuclear receptor peroxisome proliferator-activated receptor δ (PPARδ) is involved in the regulation of cardiac lipid metabolism. Here, we describe a novel PPARδ-dependent molecular cascade involving microRNA-29a (miR-29a) and atrial natriuretic factor (ANF), which is reactivated in cardiac hypertrophy. In addition, we identify a novel role of miR-29a, in which it has a cardioprotective function in isoproterenol hydrochloride-induced cardiac hypertrophy by targeting PPARδ and downregulating ANF. Finally, we provide evidence that miR-29a reduces the isoproterenol hydrochloride-induced cardiac hypertrophy response, thereby underlining the potential clinical relevance of miR-29a in which it may serve as a potent therapeutic target for heart hypertrophy treatment. 相似文献
29.
30.
Xiaoru Long Simin Li Jun Xie Wei Li Na Zang Luo Ren Yu Deng Xiaohong Xie Lijia Wang Zhou Fu Enmei Liu 《Respiratory research》2015,16(1)