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61.
Peter M. Eimon Avi Ashkenazi 《Apoptosis : an international journal on programmed cell death》2010,15(3):331-349
Apoptosis plays important roles in embryogenesis, tissue homeostasis, and immune system regulation. The zebrafish (Danio rerio) is a powerful vertebrate model organism that has been extensively used to study apoptotic cell death during normal development
and under conditions of cellular stress. In the past 5 years, a detailed picture has begun to emerge of the molecular underpinnings
of the cell-intrinsic and the cell-extrinsic apoptosis signaling pathways in zebrafish. We begin this review with an introduction
to the techniques and experimental approaches that are used to study apoptosis in zebrafish. We follow with a general overview
of developmental apoptosis during zebrafish embryogenesis. Finally, we present a comprehensive review of the intrinsic and
extrinsic apoptosis pathways in zebrafish, focusing on the high degree of conservation with humans and other mammals. Recent
publications that draw upon the unique advantages of the zebrafish system to study novel aspects of apoptosis regulation and
function are highlighted throughout. 相似文献
62.
Background
Systems biologists are faced with the difficultly of analyzing results from large-scale studies that profile the activity of many genes, RNAs and proteins, applied in different experiments, under different conditions, and reported in different publications. To address this challenge it is desirable to compare the results from different related studies such as mRNA expression microarrays, genome-wide ChIP-X, RNAi screens, proteomics and phosphoproteomics experiments in a coherent global framework. In addition, linking high-content multilayered experimental results with prior biological knowledge can be useful for identifying functional themes and form novel hypotheses. 相似文献63.
Using a surface force balance, we measured normal and shear interactions as a function of surface separation between layers of hydrogenated soy phosphatidylcholine (HSPC) small unilamellar vesicles (SUVs) adsorbed from dispersion at physiologically high salt concentrations (0.15 M NaNO3). Cryo-scanning electron microscopy shows that each surface is coated by a close-packed HSPC-SUV layer with an overlayer of liposomes on top. A clear attractive interaction between the liposome layers is seen upon approach and separation, followed by a steric repulsion upon further compression. The shear forces reveal low friction coefficients (μ = 0.008–0.0006) up to contact pressures of at least 6 MPa, comparable to those observed in the major joints. The spread in μ-values may be qualitatively accounted for by different local liposome structure at different contact points, suggesting that the intrinsic friction of the HSPC-SUV layers at this salt concentration is closer to the lower limit (μ = ∼0.0006). This low friction is attributed to the hydration lubrication mechanism arising from rubbing of the hydrated phosphocholine-headgroup layers exposed at the outer surface of each liposome, and provides support for the conjecture that phospholipids may play a significant role in biological lubrication. 相似文献
64.
Upon DNA damage, ataxia telangiectasia mutated (ATM) kinase triggers multiple events to promote cell survival and facilitate repair. If damage is excessive, ATM stimulates cytokine secretion to alert neighboring cells and apoptosis to eliminate the afflicted cell. ATM augments cell survival by activating nuclear factor (NF)-κB; however, how ATM induces cytokine production and apoptosis remains elusive. Here we uncover a p53-independent mechanism that transmits ATM-driven cytokine and caspase signals upon strong genotoxic damage. Extensive DNA lesions stimulated two sequential NF-κB activation phases, requiring ATM and NEMO/IKK-γ: The first phase induced TNF-α-TNFR1 feedforward signaling, promoting the second phase and driving RIP1 phosphorylation. In turn, RIP1 kinase triggered JNK3/MAPK10-dependent interleukin-8 secretion and FADD-mediated proapoptotic caspase-8 activation. Thus, in the context of excessive DNA damage, ATM employs NEMO and RIP1 kinase through autocrine TNF-α signaling to switch on cytokine production and caspase activation. These results shed light on cell-fate regulation by ATM. 相似文献
65.
Fernández S Eritja R Aviñó A Jaumot J Gargallo R 《International journal of biological macromolecules》2011,49(4):729-736
The influence of pH, temperature and the cationic porphyrin TMPyP4 on the conformational equilibria of the cytosine-rich strand of the human telomeric sequence 5′-(C3TA2)4-3′, as well as those of the sequence 5′-(C3TT2)4-3′, was studied. The presence of adenine bases at the loops causes the formation of two different intramolecular i-motif structures with a pH-transition midpoint around 4.6, which stability is lower than the i-motif formed by the sequence 5′-(C3TT2)4-3′. The stoichiometries of the complexes formed by these i-motif structures with TMPyP4 are also influenced by the presence of adenine at the loops. 相似文献
66.
67.
Miri Adler Avichai Tendler Jean Hausser Yael Korem Pablo Szekely Noa Bossel Yuval Hart Omer Karin Avi Mayo Uri Alon 《Molecular biology and evolution》2022,39(1)
Understanding the tradeoffs faced by organisms is a major goal of evolutionary biology. One of the main approaches for identifying these tradeoffs is Pareto task inference (ParTI). Two recent papers claim that results obtained in ParTI studies are spurious due to phylogenetic dependence (Mikami T, Iwasaki W. 2021. The flipping t-ratio test: phylogenetically informed assessment of the Pareto theory for phenotypic evolution. Methods Ecol Evol. 12(4):696–706) or hypothetical p-hacking and population-structure concerns (Sun M, Zhang J. 2021. Rampant false detection of adaptive phenotypic optimization by ParTI-based Pareto front inference. Mol Biol Evol. 38(4):1653–1664). Here, we show that these claims are baseless. We present a new method to control for phylogenetic dependence, called SibSwap, and show that published ParTI inference is robust to phylogenetic dependence. We show how researchers avoided p-hacking by testing for the robustness of preprocessing choices. We also provide new methods to control for population structure and detail the experimental tests of ParTI in systems ranging from ammonites to cancer gene expression. The methods presented here may help to improve future ParTI studies. 相似文献
68.
Polymorphism of Acetylcholinesterase in Discrete Regions of the Developing Human Fetal Brain 总被引:8,自引:3,他引:5
Haim Zakut Avi Matzkel Eduardo Schejter Adi Avni Hermona Soreq 《Journal of neurochemistry》1985,45(2):382-389
The molecular forms and membrane association of acetylcholinesterase (acetylcholine hydrolase, EC 3.1.1.7) and pseudocholinesterase (acylcholine acylhydrolase, EC 3.1.1.8) were determined in the presence of protease inhibitors in dissected regions of developing human fetal brain, as compared with parallel areas from mature brain. All areas contained substantial cholinesterase activities, of which acetylcholinesterase accounted for almost all the activity. Two major forms of acetylcholinesterase activity, sedimenting at 10-11S and 4-5S, respectively, were detected on sucrose gradients and possessed similar catalytic properties, as judged by their individual Km values toward [3H]acetylcholine (ca. 4 X 10(-4) M). The ratio between these forms varied by up to four- to fivefold, both between different areas and within particular areas at various developmental stages, but reached similar values (about 5:2) in all areas of mature brain. Acetylcholinesterase activity was ca. 35-50% low-salt-soluble and 45-65% detergent-soluble in various developmental stages and brain areas, with an increase during development of the detergent-soluble fraction of the light form. In contrast, pseudocholinesterase activity was mostly low-salt-soluble and sedimented as one component of 10-11S in all areas and developmental stages. Our findings suggest noncoordinate regulation of brain acetylcholinesterase and pseudocholinesterase, and indicate that the expression of acetylcholinesterase forms within embryonic brain areas depends both on cell type composition and on development. 相似文献
69.
Hila Shamoon Shlomo Cain Uri Shanas Avi Bar-Massada Yariv Malihi Idan Shapira 《European Journal of Wildlife Research》2018,64(3):35
Recreation activities in developed landscapes may add additional stressors that affect wildlife spatial and temporal activity patterns. We assessed medium to large mammal species response to a tourist scenic route in an agro-ecological mosaic landscape of the Shikma region, Israel. We placed 60 camera traps in an agro-ecological matrix and recorded mammals during three seasons between 2015 and 2017. We used N-mixture models to estimate mammal activity in relation with proximity to the scenic route and additional anthropogenic related factors such as traffic volume and land use. Anthropogenic development and activities had negative effects on large, endangered species, and none or positive on smaller, commensal species. Our results suggest an expansion of human recreation activity may have adverse outcomes on apex predators, which can cause a chain reaction and lead to meso-predator release, ultimately affecting prey species. The results emphasize the need for land managers to be extra cautious when attempting to add additional stressors (i.e., recreation activity) to developed landscapes such as the study area. Such landscapes can function as healthy ecosystems and provide suitable habitats for wildlife given that land managers are aware and account for wildlife-limiting factors in future development plans. 相似文献
70.