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911.
Joanna M. Tucker Lima Nicholas M. Caruso James Clugston Karen A. Kainer 《Plant Ecology》2018,219(10):1225-1245
As deforestation and land-use/land-cover change advance in tropical forest regions, an understanding of how plants adjust phenology and reproductive dynamics to altered landscapes can provide insights into plasticity, productivity, and population persistence. We compared the reproductive phenology, sex expression, and flower and fruit production of two monoecious Amazonian palms, Attalea phalerata and Attalea speciosa, in old-growth forest and as remnant trees growing in actively grazed pastures. Using 2 years of phenology data collected from natural populations near Vila Extrema, Rondônia, and eastern Acre, Brazil, we compared flowering and fruiting in the two habitats and tested for effects of palm height, crown size, and light availability on inflorescence and sex expression. Forest conversion to pasture stimulated greater overall flowering and fruiting in individual Attalea palms. As a population, remnant pasture palms continuously bore flowers and fruits year-round, while forest palms flowered seasonally in isolated peaks with consecutive months of inactivity. Crown size and greater light exposure affected flowering and fruiting dynamics in A. phalerata and A. speciosa, respectively, and increased light availability shifted A. speciosa sex expression towards greater female investment, primarily through regulation of sex determination and bud abortion. Removal of tropical forest does not always lead to the downfall of remnant tree populations, and under favorable conditions, such as abandonment of cropland and pasture, higher levels of reproduction can facilitate recovery of future generations. Tree species with flexible sex expression may be particularly resilient in the face of land-use and land-cover change. 相似文献
912.
Inhibition of yes‐associated protein suppresses brain metastasis of human lung adenocarcinoma in a murine model
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Ping‐Chih Hsu Jinbai Miao Zhen Huang Yi‐Lin Yang Zhidong Xu Joanna You Yuyuan Dai Che‐Chung Yeh Geraldine Chan Shu Liu Anatoly Urisman Cheng‐Ta Yang David M. Jablons Liang You 《Journal of cellular and molecular medicine》2018,22(6):3073-3085
Yes‐associated protein (YAP) is a main mediator of the Hippo pathway and promotes cancer development and progression in human lung cancer. We sought to determine whether inhibition of YAP suppresses metastasis of human lung adenocarcinoma in a murine model. We found that metastatic NSCLC cell lines H2030‐BrM3(K‐rasG12C mutation) and PC9‐BrM3 (EGFRΔexon19 mutation) had a significantly decreased p‐YAP(S127)/YAP ratio compared to parental H2030 (K‐rasG12C mutation) and PC9 (EGFRΔexon19 mutation) cells (P < .05). H2030‐BrM3 cells had significantly increased YAP mRNA and expression of Hippo downstream genes CTGF and CYR61 compared to parental H2030 cells (P < .05). Inhibition of YAP by short hairpin RNA (shRNA) and small interfering RNA (siRNA) significantly decreased mRNA expression in downstream genes CTGF and CYR61 in H2030‐BrM3 cells (P < .05). In addition, inhibiting YAP by YAP shRNA significantly decreased migration and invasion abilities of H2030‐BrM3 cells (P < .05). We are first to show that mice inoculated with YAP shRNA‐transfected H2030‐BrM3 cells had significantly decreased metastatic tumour burden and survived longer than control mice (P < .05). Collectively, our results suggest that YAP plays an important role in promoting lung adenocarcinoma brain metastasis and that direct inhibition of YAP by shRNA suppresses H2030‐BrM3 cell brain metastasis in a murine model. 相似文献
913.
Impact of neonatal hypoxia‐ischaemia on oligodendrocyte survival,maturation and myelinating potential
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Malgorzata Ziemka‐Nalecz Justyna Janowska Lukasz Strojek Joanna Jaworska Teresa Zalewska Malgorzata Frontczak‐Baniewicz Joanna Sypecka 《Journal of cellular and molecular medicine》2018,22(1):207-222
Hypoxic‐ischaemic episodes experienced at the perinatal period commonly lead to a development of neurological disabilities and cognitive impairments in neonates or later in childhood. Clinical symptoms often are associated with the observed alterations in white matter in the brains of diseased children, suggesting contribution of triggered oligodendrocyte/myelin pathology to the resulting disorders. To date, the processes initiated by perinatal asphyxia remain unclear, hampering the ability to develop preventions. To address the issue, the effects of temporal hypoxia‐ischaemia on survival, proliferation and the myelinating potential of oligodendrocytes were evaluated ex vivo using cultures of hippocampal organotypic slices and in vivo in rat model of perinatal asphyxia. The potential engagement of gelatinases in oligodendrocyte maturation was assessed as well. The results pointed to a significant decrease in the number of oligodendrocyte progenitor cells (OPCs), which is compensated for to a certain extent by the increased rate of OPC proliferation. Oligodendrocyte maturation seemed however to be significantly altered. An ultrastructural examination of selected brain regions performed several weeks after the insult showed however that the process of developing central nervous system myelination proceeds efficiently resulting in enwrapping the majority of axons in compact myelin. The increased angiogenesis in response to neonatal hypoxic‐ischaemic insult was also noticed. In conclusion, the study shows that hypoxic‐ischaemic episodes experienced during the most active period of nervous system development might be efficiently compensated for by the oligodendroglial cell response triggered by the insult. The main obstacle seems to be the inflammatory process modulating the local microenvironment. 相似文献
914.
Wenjie Wang Youhong Fan Xiangli Niu Min Miao Joanna Kud Bangjun Zhou Lirong Zeng Yongsheng Liu Fangming Xiao 《Plant, cell & environment》2018,41(3):689-703
Seven in absentia (SINA) protein is one subgroup of ubiquitin ligases possessing an N‐terminal cysteine‐rich really interesting new gene (RING) domain, two zinc‐finger motifs, and a C‐terminal domain responsible for substrate‐binding and dimerization. In tomato (Solanum lycopersicum), the SINA gene family has six members, and we characterize in this study all tomato SINA (SlSINA) genes and the gene products. Our results show that SlSINA genes are differentially regulated in leaf, bud, stem, flower, and root. All SlSINA proteins possess RING‐dependent E3 ubiquitin ligase activity, exhibiting similar specificity towards the E2 ubiquitin‐conjugating enzyme. SlSINA1/3/4/5/6 are localized in both cytoplasm and nucleus, whereas SlSINA2 is exclusively localized in the nucleus. Moreover, all SlSINAs can interact with each other for homo‐ or hetero‐dimerization. The functionality of SlSINA proteins has been investigated. SlSINA4 plays a positive role in defense signalling, as manifested by elicitation of E3‐dependent hypersensitive response‐like cell death; the other SlSINAs are negative regulator and capable to suppress hypersensitive response cell death. Transgenic tomato plants overexpressing SlSINA2 exhibit pale‐green leaf phenotype, suggesting SlSINA2 regulates chlorophyll level in plant cells, whereas transgenic tomato plants overexpressing SlSINA5 have altered floral structure with exserted stigma, implicating SlSINA5 plays a role in flower development. 相似文献
915.
Readily available chiral trianglimine and their (poly)oxygenated congeners represent a unique class of macrocyclic rigid compounds optimal for testing electronic and vibrational circular dichroism exciton chirality methods. Electronic and vibrational circular dichroism spectra of such trianglimines are strongly affected by polar substituents in macrocycle skeletons. Double substitution by OH groups in each aromatic fragment of the macrocycle causes sign reversal of the exciton couplet in the region of the strongest UV absorption. On the other hand, electronic circular dichroism spectrum of the macrocycle having 2 methoxy groups shows 2 exciton couplets—the long‐wavelength positive and the second of the negative sign, observed at the shorter wavelengths. VCD spectra of macrocyclic imines show vibrational exciton couplets in the region of strong C=N stretches. The signs of these couplets are positive and the opposite of the diamine chirality. For trianglimine macrocycles the interpretation of VCD spectra in terms of excitons is much more convincing than for electronic circular dichroism spectra. By contrast, trans‐1,2‐diaminocyclohexane–based vicinal diimines, being a one‐third of the respective macrocycle, do not exhibit any vibrational exciton effect. Experimental data were confronted with DFT calculations. We observed good‐to‐excellent agreement between experimental and computed data. 相似文献
916.
Chemical quenching of singlet oxygen by plastoquinols and their oxidation products in Arabidopsis
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Ursula Ferretti Joanna Ciura Brigitte Ksas Marek Rác Michaela Sedlářová Jerzy Kruk Michel Havaux Pavel Pospíšil 《The Plant journal : for cell and molecular biology》2018,95(5):848-861
Prenylquinols (tocochromanols and plastoquinols) serve as efficient physical and chemical quenchers of singlet oxygen (1O2) formed during high light stress in higher plants. Although quenching of 1O2 by prenylquinols has been previously studied, direct evidence for chemical quenching of 1O2 by plastoquinols and their oxidation products is limited in vivo. In the present study, the role of plastoquinol‐9 (PQH2‐9) in chemical quenching of 1O2 was studied in Arabidopsis thaliana lines overexpressing the SOLANESYL DIPHOSPHATE SYNTHASE 1 gene (SPS1oex) involved in PQH2‐9 and plastochromanol‐8 biosynthesis. In this work, direct evidence for chemical quenching of 1O2 by plastoquinols and their oxidation products is presented, which is obtained by microscopic techniques in vivo. Chemical quenching of 1O2 was associated with consumption of PQH2‐9 and formation of its various oxidized forms. Oxidation of PQH2‐9 by 1O2 leads to plastoquinone‐9 (PQ‐9), which is subsequently oxidized to hydroxyplastoquinone‐9 [PQ(OH)‐9]. We provide here evidence that oxidation of PQ(OH)‐9 by 1O2 results in the formation of trihydroxyplastoquinone‐9 [PQ(OH)3‐9]. It is concluded here that PQH2‐9 serves as an efficient 1O2 chemical quencher in Arabidopsis, and PQ(OH)3‐9 can be considered as a natural product of 1O2 reaction with PQ(OH)‐9. The understanding of the mechanisms underlying 1O2 chemical quenching provides information on the role of plastoquinols and their oxidation products in the response of plants to photooxidative stress. 相似文献
917.
918.
919.
Ewa Skała Tomasz Kowalczyk Monika Toma Janusz Szemraj Maciej Radek Dariusz Pytel Joanna Wieczfinska Halina Wysokińska Tomasz Śliwiński Przemysław Sitarek 《Molecular and cellular biochemistry》2018,440(1-2):89-104
The placenta plays a major role in embryo-fetal defects and intrauterine growth retardation after maternal alcohol consumption. Our aims were to determine the oxidative status and cellular and molecular oxidative stress effects on uterine myometrium and trophoblast-decidual tissue following perigestational alcohol intake at early organogenesis. CF-1 female mice were administered with 10% alcohol in drinking water for 17 days prior to and up to day 10 of gestation. Control females received ethanol-free water. Treated mice had smaller implantation sites compared to controls (p < 0.05), diminished maternal vascular lumen, and irregular/discontinuous endothelium of decidual vessels. The trophoblast giant cell layer was disorganized and presented increased abnormal nuclear frequency. The myometrium of treated females had reduced nitrite content, increased superoxide dismutase activity, and reduced glutathione (GSH) content (p < 0.05). However, the trophoblast-decidual tissue of treated females had increased nitrite content (p < 0.05), increased GSH level (p < 0.001), increased thiobarbituric acid-reactive substance concentration (p < 0.001), higher 3-nitrotyrosine immunoreaction, and increased apoptotic index (p < 0.05) compared to controls. In summary, perigestational alcohol ingestion at organogenesis induced oxidative stress in the myometrium and trophoblast-decidual tissue, mainly affecting cells and macromolecules of trophoblast and decidual tissues around early organogenesis, in CF-1 mouse, and suggests that oxidative-induced abnormal early placental formation probably leads to risk of prematurity and fetal growth impairment at term. 相似文献
920.