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排序方式: 共有190条查询结果,搜索用时 250 毫秒
1.
慈姑导管仅在根中出现。根的后生木质部中央导管由顶端平截、单穿孔的网纹导管分子连接组成;周围较小的导管分子和管胞有从梯纹管胞向导管分子演化的各种过渡类型;有一至多个梯形穿孔或单穿孔发生在导管分子的端壁或侧壁,并有分枝型导管分子存在,特别在根与主茎连接处尤为明显。管胞亦有分枝与不分枝的类型。 相似文献
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玉吊钟气生不定根根尖区域的部分表皮细胞经分裂可形成多细胞根毛。根毛长0.03mm左右,具单列细胞、双列细胞和叉状分枝类型,由基细胞和毛体细胞二部分组成。电镜显示,基细胞内部结构与表皮细胞相似。组成毛体的细胞都有分泌功能。在分泌活动期,细胞内形成大量内质网,并膨大成囊泡状或溢出囊泡,分泌停止,内质网即消失;其细胞结构的变化及主要由内质网参与分泌活动与蜜腺细胞在分泌活动中的结构变化类似。故推测多细胞根 相似文献
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目的探究抗生素雾化暴露引起的呼吸道菌群缺失对小鼠呼吸道合胞病毒(RSV)感染的影响,为临床合理使用抗生素提供指导意见。方法32只BALB/c小鼠分为2组:雾化ddH2O对照组和雾化ABX组合抗生素组,处理6 d后,进行细菌16S rRNA基因PCR检测,构建呼吸道菌群缺失小鼠模型。上述2组组内再随机分为2小组,即PBS对照组(ddH2O+PBS,ABX+PBS)和RSV感染组(ddH2O+RSV,ABX+RSV),饲养至第14天。检测和分析各组小鼠支气管肺泡灌洗液(BALF)中的炎症细胞和相关细胞因子(TNF-α、IL-8、IL-10及MCP-1)的数量和水平,观察肺组织病理学状况及检测病毒载量。结果BALF中细菌DNA提取和16S rRNA基因PCR检测显示,雾化ABX组合抗生素处理能够有效地剔除呼吸道菌群。BALF中炎症细胞和相关细胞因子检测显示,ABX+RSV组炎症细胞总数明显增多(P<0.05),分类以巨噬细胞和淋巴细胞为主;且细胞因子TNF-α、IL-8、MCP-1及IL-10水平显著升高(均P<0.05)。肺部HE染色显示,感染RSV后ddH2O+RSV组和ABX+RSV组小鼠肺部损伤明显加重(均P≤0.01),与ddH2O+RSV组相比较,ABX+RSV组的病毒载量明显升高(t=2.7160,P=0.0217)。结论雾化ABX组合抗生素不仅能够有效地剔除呼吸道菌群,而且明显增加了小鼠感染RSV的风险,导致呼吸道炎症加重,以及病毒载量升高。 相似文献
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Zhenghua Gong Jiayu Lin Jie Zheng Liya Wei Li Liu Yanzhong Peng Weicheng Liang Guoxin Hu 《Journal of cellular biochemistry》2020,121(2):1431-1440
It is well characterized that activated hepatic stellate cells (HSCs) exert critical functions in accelerating the progression of liver fibrosis. Previous studies have indicated that Dahuang Zhechong pill (DHZCP), a traditional Chinese herbal medicine, is capable of inactivating HSCs and thus attenuate the formation of liver fibrosis in rats. However, pharmacological mechanisms of DHZCP in alleviating liver fibrosis remain unclear. This study aims to investigate the antifibrotic role of DHZCP through inhibiting the phosphatidylinositol 3-kinase (PI3K)-protein kinase B (Akt) pathway. DHZCP was found to significantly suppresses extracellular matrix formation and immune cell infiltration, thus alleviating liver fibrosis symptoms in the in vivo model. Moreover, DHZCP reduced serum levels of transforming growth factor β1 and tumor necrosis factor-α in rats with liver fibrosis. DHZCP treatment remarkably downregulated protein levels of PI3K and phosphorylated Akt, as well as fibrosis markers. In vitro experiments further demonstrated that DHZCP markedly suppressed HSCs proliferation by downregulating PI3K/Akt, which exerted a synergistic effect with the PI3K inhibitor LY294002. To sum up, our results confirmed that DHZCP exerted an antifibrotic effect in the animal model through inactivating the PI3K/Akt pathway, thus protecting rats from liver injury. 相似文献
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Hua Qin Qiang Gu Sundaram Kuppu Li Sun Xunlu Zhu Neelam Mishra Rongbin Hu Guoxin Shen Junling Zhang Yizheng Zhang Longfu Zhu Xianlong Zhang Mark Burow Paxton Payton Hong Zhang 《Plant biotechnology reports》2013,7(3):345-355
The Arabidopsis gene AVP1 encodes an H+-pyrophosphatase that functions as a proton pump at the vacuolar membranes, generating a proton gradient across vacuolar membranes, which serves as the driving force for many secondary transporters on vacuolar membranes such as Na+/H+-antiporters. Overexpression of AVP1 could improve drought tolerance and salt tolerance in transgenic plants, suggesting a possible way in improving drought and salt tolerance in crops. The AVP1 was therefore introduced into peanut by Agrobacterium-mediated transformation. Analysis of AVP1-expressing peanut indicated that AVP1-overexpression in peanut could improve both drought and salt tolerance in greenhouse and growth chamber conditions, as AVP1-overexpressing peanuts produced more biomass and maintained higher photosynthetic rates under both drought and salt conditions. In the field, AVP1-overexpressing peanuts also outperformed wild-type plants by having higher photosynthetic rates and producing higher yields under low irrigation conditions. 相似文献
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Guoxin Zhang Hongli Li Ruimei Sun Peirui Li Zhiyi Yang Yuanyuan Liu Zhaoyan Wang Yuling Yang Chonggao Yin 《Journal of cellular and molecular medicine》2019,23(5):3271-3279
The triple‐negative breast cancer is the most malignant type of breast cancer. Its pathogenesis and prognosis remain poor despite the significant advances in breast cancer diagnosis and therapy. Meanwhile, long noncoding RNAs (LncRNAs) play a pivotal role in the progression of malignant tumors. In this study, we found that LncRNA‐ZEB2‐AS1 was dramatically up‐regulated in our breast cancer specimens and cells (MDA231), especially in metastatic tumor specimens and highly invasive cells, and high lncRNA‐ZEB2‐AS1 expression is associated with clinicopathologic features and short survival of breast cancer patients. LncRNA‐ZEB2‐AS1 promotes the proliferation and metastasis of MDA231 cells in SCID mice. Thus, it is regarded as an oncogene in triple‐negative breast cancer. It is mainly endo‐nuclear and situated near ZEB2, positively regulating ZEB2 expression and activating the epithelial mesenchymal transition via the PI3K/Akt/GSK3β/Zeb2 signaling pathway. Meanwhile, EGF‐induced F‐actin polymerization in MDA231 cells can be suppressed by reducing lncRNA‐ZEB2‐AS1 expression. The migration and invasion of triple‐negative breast cancer can be altered through cytoskeleton rearrangement. In summary, we demonstrated that lncRNA‐ZEB2‐AS1 is an important factor affecting the development of triple‐negative breast cancer and thus a potential oncogene target. 相似文献
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Zhiwu Dan Yunping Chen Yanghong Xu Junran Huang Jishuai Huang Jun Hu Guoxin Yao Yingguo Zhu Wenchao Huang 《Plant biotechnology journal》2019,17(5):906-913
Marker‐based prediction holds great promise for improving current plant and animal breeding efficiencies. However, the predictabilities of complex traits are always severely affected by negative factors, including distant relatedness, environmental discrepancies, unknown population structures, and indeterminate numbers of predictive variables. In this study, we utilised two independent F1 hybrid populations in the years 2012 and 2015 to predict rice thousand grain weight (TGW) using parental untargeted metabolite profiles with a partial least squares regression method. A stable predictive model for TGW was built based on hybrids from the population in 2012 (r = 0.75) but failed to properly predict TGW for hybrids from the population in 2015 (r = 0.27). After integrating hybrids from both populations into the training set, the TGW of hybrids could be predicted but was largely dependent on population structures. Then, core hybrids from each population were determined by principal component analysis and the TGW of hybrids in both environments were successfully predicted (r > 0.60). Moreover, adjusting the population structures and numbers of predictive analytes increased TGW predictability for hybrids in 2015 (r = 0.72). Our study demonstrates that the TGW of F1 hybrids across environments can be accurately predicted based on parental untargeted metabolite profiles with a core hybridisation strategy in rice. Metabolic biomarkers identified from early developmental stage tissues, which are grown under experimental conditions, may represent a workable approach towards the robust prediction of major agronomic traits for climate‐adaptive varieties. 相似文献