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Cellular theory

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https://www.readbyqxmd.com/read/28088300/cytoplasmic-rna-protein-particles-exhibit-non-gaussian-subdiffusive-behavior
#1
Thomas J Lampo, Stella Stylianidou, Mikael P Backlund, Paul A Wiggins, Andrew J Spakowitz
The cellular cytoplasm is a complex, heterogeneous environment (both spatially and temporally) that exhibits viscoelastic behavior. To further develop our quantitative insight into cellular transport, we analyze data sets of mRNA molecules fluorescently labeled with MS2-GFP tracked in real time in live Escherichia coli and Saccharomyces cerevisiae cells. As shown previously, these RNA-protein particles exhibit subdiffusive behavior that is viscoelastic in its origin. Examining the ensemble of particle displacements reveals a Laplace distribution at all observed timescales rather than the Gaussian distribution predicted by the central limit theorem...
January 11, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28087483/cell-number-per-spheroid-and-electrical-conductivity-of-nanowires-influence-the-function-of-silicon-nanowired-human-cardiac-spheroids
#2
Yu Tan, Dylan Richards, Robert C Coyle, Jenny Yao, Ruoyu Xu, Wenyu Gou, Hongjun Wang, Donald R Menick, Bozhi Tian, Ying Mei
: Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) provide an unlimited cell source to treat cardiovascular diseases, the leading cause of death worldwide. However, current hiPSC-CMs retain an immature phenotype that leads to difficulties for integration with adult myocardium after transplantation. To address this, we recently utilized electrically conductive silicon nanowires (e-SiNWs) to facilitate self-assembly of hiPSC-CMs to form nanowired hiPSC cardiac spheroids...
January 10, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28087421/physiology-anaerobes-and-the-origin-of-mitosing-cells-50-years-on
#3
William F Martin
Endosymbiotic theory posits that some organelles or structures of eukaryotic cells stem from free-living prokaryotes that became endosymbionts within a host cell. Endosymbiosis has a long and turbulent history of controversy and debate going back over 100 years. The 1967 paper by Lynn Sagan (later Lynn Margulis) forced a reluctant field to take endosymbiotic theory seriously and to incorporate it into the fabric of evolutionary thinking. Margulis envisaged three cellular partners associating in series at eukaryotic origin: the host (an engulfing bacterium), the mitochondrion (a respiring bacterium), and the flagellum (a spirochaete), with lineages descended from that flagellated eukaryote subsequently acquiring plastids from cyanobacteria, but on multiple different occasions in her 1967 account...
January 10, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28079576/mixed-gangliocytoma-pituitary-adenoma-insights-on-the-pathogenesis-of-a-rare-sellar-tumor
#4
M Beatriz S Lopes, Emily Sloan, Julie Polder
Gangliocytomas originating in the sellar region are rare; most are tumors composed of gangliocytic and pituitary adenomatous elements, forming the so-called mixed gangliocytoma-pituitary adenoma. The majority of mixed gangliocytoma adenomas are associated with endocrinopathies, mainly acromegaly and less often Cushing disease and hyperprolactinemia. In the present study, 10 cases of mixed gangliocytoma and somatotroph adenomas were evaluated for patterns of cellular differentiation and expression of lineage-specific transcription factors...
January 10, 2017: American Journal of Surgical Pathology
https://www.readbyqxmd.com/read/28077663/temporally-precise-control-of-single-neuron-spiking-by-juxtacellular-nanostimulation
#5
Maik Christopher Stüttgen, Lourens Jp Nonkes, Hans-Rüdiger Ap Geis, Paul H Tiesinga, Arthur R Houweling
Temporal patterns of action potentials influence a variety of activity-dependent intra- and inter-cellular processes and play an important role in theories of neural coding. Elucidating the mechanisms underlying these phenomena requires imposing spike trains with precisely defined patterns, but this has been challenging due to the limitations of existing stimulation techniques. Here we present a new nanostimulation method providing control over the action potential output of individual cortical neurons. Spikes are elicited through the juxtacellular application of short-duration fluctuating currents ('kurzpulses'), allowing for the sub-millisecond precise and reproducible induction of arbitrary patterns of action potentials at all physiologically relevant firing frequencies (<120 Hz), including minute-long spike trains recorded in freely moving animals...
January 11, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28072544/why-can-unnatural-electron-acceptors-protect-photosynthesizing-organisms-but-kill-the-others
#6
Stanislav Anatolievich Pshenichnyuk, Alexei S Komolov
The polychlorinated compounds captafol (CPL) and 2,6-dichloroisonicotinic acid (INI) are able to protect plants acting as a fungicide or an inductor of plant resistance, respectively. At the same time, CPL and INI are dangerous for the respiratory organisms, i.e. mammalians, bacteria and fungi. The high electron-withdrawing ability of these compounds enables them to serve as unnatural electron acceptors in the cellular ambient near to electron transport pathways located in the thylakoid membrane of chloroplasts or in the mitochondrial respiratory chain...
January 10, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28043053/the-decay-of-redox-stress-response-capacity-is-a-substantive-characteristic-of-aging-revising-the-redox-theory-of-aging
#7
Jiao Meng, Zhenyu Lv, Xinhua Qiao, Xiaopeng Li, Yazi Li, Yuying Zhang, Chang Chen
Aging is tightly associated with redox events. The free radical theory of aging indicates that redox imbalance may be an important factor in the aging process. Most studies about redox and aging focused on the static status of oxidative stress levels, there has been little research investigating differential responses to redox challenge during aging. In this study, we used Caenorhabditis elegans and human fibroblasts as models to compare differential responses to oxidative stress challenge in young and old individuals...
December 28, 2016: Redox Biology
https://www.readbyqxmd.com/read/28039592/loss-or-mislocalization-of-aquaporin-4-affects-diffusion-properties-and-intermediary-metabolism-in-gray-matter-of-mice
#8
T Pavlin, E A Nagelhus, C Brekken, E M Eyjolfsson, A Thoren, O Haraldseth, U Sonnewald, O P Ottersen, A K Håberg
The first aim of this study was to determine how complete or perivascular loss of aquaporin-4 (AQP4) water channels affects membrane permeability for water in the mouse brain grey matter in the steady state. Time-dependent diffusion magnetic resonance imaging was performed on global Aqp4 knock out (KO) and α-syntrophin (α-syn) KO mice, in the latter perivascular AQP4 are mislocalized, but still functioning. Control animals were corresponding wild type (WT) mice. By combining in vivo diffusion measurements with the effective medium theory and previously measured extra-cellular volume fractions, the effects of membrane permeability and extracellular volume fraction were uncoupled for Aqp4 and α-syn KO...
December 30, 2016: Neurochemical Research
https://www.readbyqxmd.com/read/28036211/load-response-of-the-flagellar-beat
#9
Gary S Klindt, Christian Ruloff, Christian Wagner, Benjamin M Friedrich
Cilia and flagella exhibit regular bending waves that perform mechanical work on the surrounding fluid, to propel cellular swimmers and pump fluids inside organisms. Here, we quantify a force-velocity relationship of the beating flagellum, by exposing flagellated Chlamydomonas cells to controlled microfluidic flows. A simple theory of flagellar limit-cycle oscillations, calibrated by measurements in the absence of flow, reproduces this relationship quantitatively. We derive a link between the energy efficiency of the flagellar beat and its ability to synchronize to oscillatory flows...
December 16, 2016: Physical Review Letters
https://www.readbyqxmd.com/read/28027311/somatic-mutation-patterns-in-hemizygous-genomic-regions-unveil-purifying-selection-during-tumor-evolution
#10
Jimmy Van den Eynden, Swaraj Basu, Erik Larsson
Identification of cancer driver genes using somatic mutation patterns indicative of positive selection has become a major goal in cancer genomics. However, cancer cells additionally depend on a large number of genes involved in basic cellular processes. While such genes should in theory be subject to strong purifying (negative) selection against damaging somatic mutations, these patterns have been elusive and purifying selection remains inadequately explored in cancer. Here, we hypothesized that purifying selection should be evident in hemizygous genomic regions, where damaging mutations cannot be compensated for by healthy alleles...
December 2016: PLoS Genetics
https://www.readbyqxmd.com/read/28018487/inherent-variability-of-cancer-specific-aneuploidy%C3%A2-generates-metastases
#11
Mathew Bloomfield, Peter Duesberg
BACKGROUND: The genetic basis of metastasis is still unclear because metastases carry individual karyotypes and phenotypes, rather than consistent mutations, and are rare compared to conventional mutation. There is however correlative evidence that metastasis depends on cancer-specific aneuploidy, and that metastases are karyotypically related to parental cancers. Accordingly we propose that metastasis is a speciation event. This theory holds that cancer-specific aneuploidy varies the clonal karyotypes of cancers automatically by unbalancing thousands of genes, and that rare variants form new autonomous subspecies with metastatic or other non-parental phenotypes like drug-resistance - similar to conventional subspeciation...
2016: Molecular Cytogenetics
https://www.readbyqxmd.com/read/28010898/the-etiopathogenesis-of-diffuse-low-grade-gliomas
#12
REVIEW
Amélie Darlix, Catherine Gozé, Valérie Rigau, Luc Bauchet, Luc Taillandier, Hugues Duffau
The origins of diffuse low-grade gliomas (DLGG) are unknown. Beyond some limited data on their temporal and cellular origins, the mechanisms and risk factors involved are poorly known. First, based on strong relationships between DLGG development and the eloquence of brain regions frequently invaded by these tumors, we propose a "functional theory" to explain the origin of DLGG. Second, the biological pathways involved in DLGG genesis may differ according to tumor location (anatomo-molecular correlations). The cellular and molecular mechanisms of such "molecular theory" will be reviewed...
January 2017: Critical Reviews in Oncology/hematology
https://www.readbyqxmd.com/read/28007654/archaeal-phospholipids-structural-properties-and-biosynthesis
#13
REVIEW
Antonella Caforio, Arnold J M Driessen
Phospholipids are major components of the cellular membranes present in all living organisms. They typically form a lipid bilayer that embroiders the cell or cellular organelles, constitute a barrier for ions and small solutes and form a matrix that supports the function of membrane proteins. The chemical composition of the membrane phospholipids present in the two prokaryotic domains Archaea and Bacteria are vastly different. Archaeal lipids are composed of highly-methylated isoprenoid chains that are ether-linked to a glycerol-1-phosphate backbone while bacterial phospholipids consist of straight fatty acids bound by ester bonds to the enantiomeric glycerol-3-phosphate backbone...
December 20, 2016: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28006935/multiple-roles-of-mitochondria-in-aging-processes
#14
M Cedikova, P Pitule, M Kripnerova, M Markova, J Kuncova
Aging is a multifactorial process influenced by genetic factors, nutrition, and lifestyle. According to mitochondrial theory of aging, mitochondrial dysfunction is widely considered a major contributor to age-related processes. Mitochondria are both the main source and targets of detrimental reactions initiated in association with age-dependent deterioration of the cellular functions. Reactions leading to increased reactive oxygen species generation, mtDNA mutations, and oxidation of mitochondrial proteins result in subsequent induction of apoptotic events, impaired oxidative phosphorylation capacity, mitochondrial dynamics, biogenesis and autophagy...
December 22, 2016: Physiological Research
https://www.readbyqxmd.com/read/28006727/the-relationship-between-mri-quantitative-parameters-and-the-expression-of-hypoxia-inducible-factor-1-alpha-in-cerebral-astrocytoma
#15
Chang Shu, Jinhuan Wang
OBJECTIVE: Astrocytoma is the common type of glioma. But the MRI scanning for astrocytoma preoperation pathological diagnosis is not exact. The purpose of this study was to use the MRI multi quantitative parameters to improve the diagnosis of astrocytoma and exploit their molecular mechanism related to the expression of HIF-1α. METHODS: Superconducting MR scanner and its work station were used to calculate the MRI multi quantitative parameters of the selected patients in this experiment...
November 23, 2016: Clinical Neurology and Neurosurgery
https://www.readbyqxmd.com/read/28006034/peripheral-organs-of-dengue-fatal-cases-present-strong-pro-inflammatory-response-with-participation-of-ifn-gamma-tnf-alpha-and-rantes-producing-cells
#16
Tiago F Póvoa, Edson R A Oliveira, Carlos A Basílio-de-Oliveira, Gerard J Nuovo, Vera L A Chagas, Natália G Salomão, Ester M Mota, Marciano V Paes
Dengue disease is an acute viral illness caused by dengue virus (DENV) that can progress to hemorrhagic stages leading to about 20000 deaths every year worldwide. Despite many clinical investigations regarding dengue, the immunopathogenic process by which infected patients evolve to the severe forms is not fully understood. Apart from differences in virulence and the antibody cross reactivity that can potentially augment virus replication, imbalanced cellular immunity is also seen as a major concern in the establishment of severe dengue...
2016: PloS One
https://www.readbyqxmd.com/read/27998090/monitoring-chemical-and-biological-electron-transfer-reactions-with-a-fluorogenic-vitamin-k-analogue-probe
#17
Mei-Ni Belzile, Robert Godin, Andrés M Durantini, Gonzalo Cosa
We report herein the design, synthesis, and characterization of a two-segment fluorogenic analogue of vitamin K, B-VKQ, prepared by coupling vitamin K3, also known as menadione (a quinone redox center), to a boron-dipyrromethene (BODIPY) fluorophore (a lipophilic reporter segment). Oxidation-reduction reactions, spectroelectrochemical studies, and enzymatic assays conducted in the presence of DT-diaphorase illustrate that the new probe shows reversible redox behavior on par with that of vitamin K, provides a high-sensitivity fluorescence signal, and is compatible with biological conditions, opening the door to monitor remotely (i...
December 21, 2016: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/27991663/is-the-ice-bath-finally-melting-cwi-is-no-greater-than-active-recovery-upon-local-and-systemic-inflammatory-cellular-stress-in-humans
#18
R Allan, Mawhinney Cr
Over the past decade, significant research has focussed on optimising the recovery of elite athletes. The premise behind such a theory is that sub-optimal recovery often leads to fatigue, reducing the quality of subsequent training sessions and/or competitive performances, whilst potentially hindering adaptive processes. There is now a plethora of research focussing on the impact of one such recovery strategy, cold-water immersion (CWI), and the benefits it may provide post-exercise. This article is protected by copyright...
December 19, 2016: Journal of Physiology
https://www.readbyqxmd.com/read/27989191/determinants-of-fe-2-over-m-2-m-mg-mn-zn-selectivity-in-non-heme-iron-proteins
#19
Todor Dudev, Valia Nikolova
Iron cations are indispensable players in a number of vital biological processes such as respiration, cell division, nitrogen fixation, oxygen transport, nucleotide synthesis, oxidant protection, O2 activation in the metabolism of various organic substrates, gene regulation, and protein structure stabilization. The basic mechanisms and factors governing the competition between Fe(2+) and other metal species from the cellular fluids such as Mg(2+), Mn(2+), and Zn(2+) are, however, not well understood, and several outstanding questions remain...
December 19, 2016: Inorganic Chemistry
https://www.readbyqxmd.com/read/27981350/the-role-of-bone-resorption-in-the-etiopathogenesis-of-acquired-middle-ear-cholesteatoma
#20
REVIEW
Shumin Xie, Xiaoli Wang, Jihao Ren, Wei Liu
Cholesteatoma is a destructive squamous epithelial lesion of the temporal bone which gradually expands and leads to serious complications by destruction of nearby bony structures. Erosion caused by bone resorption of the ossicular chain and bony labyrinth may result in hearing loss, vestibular dysfunction, facial paralysis, labyrinthine fistulae and intracranial complications. The exact underlying cellular and molecular mechanism of bone resorption in acquired cholesteatoma still remains unexplained. Pubmed database and China National Knowledge Infrastructure were screened for articles focusing on bone resorption in acquired cholesteatoma...
December 16, 2016: European Archives of Oto-rhino-laryngology
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