Articles de revues : « Modulation of cell size »

1

Vanoni, M., R. L. Rossi, L. Querin, V. Zinzalla et L. Alberghina. « Glucose modulation of cell size in yeast ». Biochemical Society Transactions 33, n^o 1 (1 février 2005) : 294–96. http://dx.doi.org/10.1042/bst0330294.

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Saccharomyces cerevisiae cells grown in glucose have larger average size than cells grown in ethanol. Besides, yeast must reach a carbon source-modulated critical cell size in order to enter S phase at Start. This control is of outmost physiological relevance, since it allows us to coordinate cell growth with cell cycle progression and it is responsible for cell size homeostasis. The cell sizer mechanism requires the overcoming of two sequential thresholds, involving Cln3 and Far1, and Clb5,6 and Sic1, respectively. When both thresholds are non-functional, carbon source modulation of cell size at Start is completely abolished. Since inactivation of extracellular glucose sensing through deletion of either the GPR1 or the GPA2 gene causes a marked, but partial, reduction in the ability to modulate cell size and protein content at Start, it is proposed that both extracellular and intracellular glucose signalling is required for properly setting the cell sizer in glucose media.

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Duncombe, Todd A., Chi-Chih Kang, Santanu Maity, Toby M. Ward, Mark D. Pegram, Niren Murthy et Amy E. Herr. « Hydrogel Pore-Size Modulation for Enhanced Single-Cell Western Blotting ». Advanced Materials 28, n^o 2 (16 novembre 2015) : 327–34. http://dx.doi.org/10.1002/adma.201503939.

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Baroni, M. D., E. Martegani, P. Monti et L. Alberghina. « Cell size modulation by CDC25 and RAS2 genes in Saccharomyces cerevisiae ». Molecular and Cellular Biology 9, n^o 6 (juin 1989) : 2715–23. http://dx.doi.org/10.1128/mcb.9.6.2715-2723.1989.

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A detailed kinetic analysis of the cell cycle of cdc25-1, RAS2Val-19, or cdc25-1/RAS2Val-19 mutants during exponential growth is presented. At the permissive temperature (24 degrees C), cdc25-1 cells show a longer G1/unbudded phase of the cell cycle and have a smaller critical cell size required for budding without changing the growth rate in comparison to an isogenic wild type. The RAS2Val-19 mutation efficiently suppresses the ts growth defect of the cdc25-1 mutant at 36 degrees C and the increase of G1 phase at 24 degrees C. Moreover, it causes a marked increase of the critical cell mass required to enter into a new cell division cycle compared with that of the wild type. Since the critical cell mass is physiologically modulated by nutritional conditions, we have also studied the behavior of these mutants in different media. The increase in cell size caused by the RAS2Val-19 mutation is evident in all tested growth conditions, while the effect of cdc25-1 is apparently more pronounced in rich culture media. CDC25 and RAS2 gene products have been showed to control cell growth by regulating the cyclic AMP metabolic pathway. Experimental evidence reported herein suggests that the modulation of the critical cell size by CDC25 and RAS2 may involve adenylate cyclase.

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Baroni, M. D., E. Martegani, P. Monti et L. Alberghina. « Cell size modulation by CDC25 and RAS2 genes in Saccharomyces cerevisiae. » Molecular and Cellular Biology 9, n^o 6 (juin 1989) : 2715–23. http://dx.doi.org/10.1128/mcb.9.6.2715.

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A detailed kinetic analysis of the cell cycle of cdc25-1, RAS2Val-19, or cdc25-1/RAS2Val-19 mutants during exponential growth is presented. At the permissive temperature (24 degrees C), cdc25-1 cells show a longer G1/unbudded phase of the cell cycle and have a smaller critical cell size required for budding without changing the growth rate in comparison to an isogenic wild type. The RAS2Val-19 mutation efficiently suppresses the ts growth defect of the cdc25-1 mutant at 36 degrees C and the increase of G1 phase at 24 degrees C. Moreover, it causes a marked increase of the critical cell mass required to enter into a new cell division cycle compared with that of the wild type. Since the critical cell mass is physiologically modulated by nutritional conditions, we have also studied the behavior of these mutants in different media. The increase in cell size caused by the RAS2Val-19 mutation is evident in all tested growth conditions, while the effect of cdc25-1 is apparently more pronounced in rich culture media. CDC25 and RAS2 gene products have been showed to control cell growth by regulating the cyclic AMP metabolic pathway. Experimental evidence reported herein suggests that the modulation of the critical cell size by CDC25 and RAS2 may involve adenylate cyclase.

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Marais, A. David. « Therapeutic modulation of low-density lipoprotein size ». Current Opinion in Lipidology 11, n^o 6 (décembre 2000) : 597–602. http://dx.doi.org/10.1097/00041433-200012000-00005.

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Zhou, Shaoli, Tianquan Yang, Yawen Mao, Ye Liu, Shiqi Guo, Ruoruo Wang, Genwang Fangyue et al. « The F-box protein MIO1/SLB1 regulates organ size and leaf movement in Medicago truncatula ». Journal of Experimental Botany 72, n^o 8 (28 janvier 2021) : 2995–3011. http://dx.doi.org/10.1093/jxb/erab033.

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Abstract The size of leaf and seed organs, determined by the interplay of cell proliferation and expansion, is closely related to the final yield and quality of forage and crops. Yet the cellular and molecular mechanisms underlying organ size modulation remain poorly understood, especially in legumes. Here, MINI ORGAN1 (MIO1), which encodes an F-box protein SMALL LEAF AND BUSHY1 (SLB1) recently reported to control lateral branching in Medicago truncatula, was identified as a key regulator of organ size. We show that loss-of-function of MIO1/SLB1 severely reduced organ size. Conversely, plants overexpressing MIO1/SLB1 had enlarged organs. Cellular analysis revealed that MIO1/SLB1 controlled organ size mainly by modulating primary cell proliferation during the early stages of leaf development. Biochemical analysis revealed that MIO1/SLB1 could form part of SKP1/Cullin/F-box (SCF) E3 ubiquitin ligase complex, to target BIG SEEDS1 (BS1), a repressor of primary cell division, for degradation. Interestingly, we found that MIO1/SLB1 also played a key role in pulvinus development and leaf movement by modulating cell proliferation of the pulvinus as leaves developed. Our study not only demonstrates a conserved role of MIO1/SLB1 in the control of organ size in legumes, but also sheds light on the novel function of MIO1/SLB1 in leaf movement.

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Cipollina, Chiara, Lilia Alberghina, Danilo Porro et Marina Vai. « SFP1 is involved in cell size modulation in respiro-fermentative growth conditions ». Yeast 22, n^o 5 (2005) : 385–99. http://dx.doi.org/10.1002/yea.1218.

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Mumtaz, Muhammad Ali, Fangman Li, Xingyu Zhang, Jinbao Tao, Pingfei Ge, Ying Wang, Yaru Wang, Wenxian Gai, Haiqiang Dong et Yuyang Zhang. « Altered brassinolide sensitivity1 Regulates Fruit Size in Association with Phytohormones Modulation in Tomato ». Horticulturae 8, n^o 11 (31 octobre 2022) : 1008. http://dx.doi.org/10.3390/horticulturae8111008.

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BRs (Brassinosteroids) regulate many essential pathways related to growth, cell elongation, cell expansion, plant architecture, and fruit development. The potential exogenous application of BR-derivatives has been proven to stimulate plant growth and development, including quality attributes of fruits, whereas its biosynthesis inhibition has shown the opposite effect. In this study, BR-insensitive tomato mutants were used to reveal the potential function of BR signaling in the regulation of fruit development to elaborate the regulatory mechanism of BR signaling in tomato fruits. The BR-signaling mutant exhibited a typical dwarf phenotype and reduced vegetative growth, fruit size, and weight. Microscopic and transcriptional evaluation of the abs1 mutant fruits implies that reduced cell size and number are responsible for the phenotypic variations. Additionally, we also found that the altered content of phytohormones, such as auxin, gibberellin, cytokinin, and ethylene levels, contributed to altered fruit development. Moreover, fruit growth and cell development-specific gene expression levels were downregulated in BR-insensitive plants; culminating in reduced cell size, cell number, and cell layers. These findings provide insight into physio-chemical changes during fruit development in response to BR-insensitivity.

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Jang, Seonghoe, Jwa-Yeong Cho, Gyung-Ran Do, Yeeun Kang, Hsing-Yi Li, Jaeeun Song, Ho-Youn Kim, Beom-Gi Kim et Yue-Ie Hsing. « Modulation of Rice Leaf Angle and Grain Size by Expressing OsBCL1 and OsBCL2 under the Control of OsBUL1 Promoter ». International Journal of Molecular Sciences 22, n^o 15 (21 juillet 2021) : 7792. http://dx.doi.org/10.3390/ijms22157792.

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Leaf angle and grain size are important agronomic traits affecting rice productivity directly and/or indirectly through modulating crop architecture. OsBC1, as a typical bHLH transcription factor, is one of the components comprising a complex formed with LO9-177 and OsBUL1 contributing to modulation of rice leaf inclination and grain size. In the current study, two homologues of OsBC1, OsBCL1 and OsBCL2 were functionally characterized by expressing them under the control of OsBUL1 promoter, which is preferentially expressed in the lamina joint and the spikelet of rice. Increased leaf angle and grain length with elongated cells in the lamina joint and the grain hull were observed in transgenic rice containing much greater gibberellin A3 (GA3) levels than WT, demonstrating that both OsBCL1 and OsBCL2 are positive regulators of cell elongation at least partially through increased GA biosynthesis. Moreover, the cell elongation was likely due to cell expansion rather than cell division based on the related gene expression and, the cell elongation-promoting activities of OsBCL1 and OsBCL2 were functional in a dicot species, Arabidopsis.

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Mitra, Mautusi, Henning Kirst, David Dewez et Anastasios Melis. « Modulation of the light-harvesting chlorophyll antenna size in Chlamydomonas reinhardtii by TLA1 gene over-expression and RNA interference ». Philosophical Transactions of the Royal Society B : Biological Sciences 367, n^o 1608 (19 décembre 2012) : 3430–43. http://dx.doi.org/10.1098/rstb.2012.0229.

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Truncated light-harvesting antenna 1 ( TLA1 ) is a nuclear gene proposed to regulate the chlorophyll (Chl) antenna size in Chlamydomonas reinhardtii . The Chl antenna size of the photosystems and the chloroplast ultrastructure were manipulated upon TLA1 gene over-expression and RNAi downregulation. The TLA1 over-expressing lines possessed a larger chlorophyll antenna size for both photosystems and contained greater levels of Chl b per cell relative to the wild type. Conversely, TLA1 RNAi transformants had a smaller Chl antenna size for both photosystems and lower levels of Chl b per cell. Western blot analyses of the TLA1 over-expressing and RNAi transformants showed that modulation of TLA1 gene expression was paralleled by modulation in the expression of light-harvesting protein, reaction centre D1 and D2, and VIPP1 genes. Transmission electron microscopy showed that modulation of TLA1 gene expression impacts the organization of thylakoid membranes in the chloroplast. Over-expressing lines showed well-defined grana, whereas RNAi transformants possessed loosely held together and more stroma-exposed thylakoids. Cell fractionation suggested localization of the TLA1 protein in the inner chloroplast envelope and potentially in association with nascent thylakoid membranes, indicating a role in Chl antenna assembly and thylakoid membrane biogenesis. The results provide a mechanistic understanding of the Chl antenna size regulation by the TLA1 gene.

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Lambert, Ambroise, Aster Vanhecke, Anna Archetti, Seamus Holden, Felix Schaber, Zachary Pincus, Michael T. Laub, Erin Goley et Suliana Manley. « Constriction Rate Modulation Can Drive Cell Size Control and Homeostasis in C. crescentus ». iScience 4 (juin 2018) : 180–89. http://dx.doi.org/10.1016/j.isci.2018.05.020.

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Nicolas, Damien, Benjamin Zoller, David M. Suter et Felix Naef. « Modulation of transcriptional burst frequency by histone acetylation ». Proceedings of the National Academy of Sciences 115, n^o 27 (18 juin 2018) : 7153–58. http://dx.doi.org/10.1073/pnas.1722330115.

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Many mammalian genes are transcribed during short bursts of variable frequencies and sizes that substantially contribute to cell-to-cell variability. However, which molecular mechanisms determine bursting properties remains unclear. To probe putative mechanisms, we combined temporal analysis of transcription along the circadian cycle with multiple genomic reporter integrations, using both short-lived luciferase live microscopy and single-molecule RNA-FISH. Using the Bmal1 circadian promoter as our model, we observed that rhythmic transcription resulted predominantly from variations in burst frequency, while the genomic position changed the burst size. Thus, burst frequency and size independently modulated Bmal1 transcription. We then found that promoter histone-acetylation level covaried with burst frequency, being greatest at peak expression and lowest at trough expression, while remaining unaffected by the genomic location. In addition, specific deletions of ROR-responsive elements led to constitutively elevated histone acetylation and burst frequency. We then investigated the suggested link between histone acetylation and burst frequency by dCas9p300-targeted modulation of histone acetylation, revealing that acetylation levels influence burst frequency more than burst size. The correlation between acetylation levels at the promoter and burst frequency was also observed in endogenous circadian genes and in embryonic stem cell fate genes. Thus, our data suggest that histone acetylation-mediated control of transcription burst frequency is a common mechanism to control mammalian gene expression.

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Krylyshkina, Olga, Irina Kaverina, Wolfgang Kranewitter, Walter Steffen, Maria C. Alonso, Robert A. Cross et J. Victor Small. « Modulation of substrate adhesion dynamics via microtubule targeting requires kinesin-1 ». Journal of Cell Biology 156, n^o 2 (21 janvier 2002) : 349–60. http://dx.doi.org/10.1083/jcb.200105051.

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Recent studies have shown that the targeting of substrate adhesions by microtubules promotes adhesion site disassembly (Kaverina, I., O. Krylyshkina, and J.V. Small. 1999. J. Cell Biol. 146:1033–1043). It was accordingly suggested that microtubules serve to convey a signal to adhesion sites to modulate their turnover. Because microtubule motors would be the most likely candidates for effecting signal transmission, we have investigated the consequence of blocking microtubule motor activity on adhesion site dynamics. Using a function-blocking antibody as well as dynamitin overexpression, we found that a block in dynein–cargo interaction induced no change in adhesion site dynamics in Xenopus fibroblasts. In comparison, a block of kinesin-1 activity, either via microinjection of the SUK-4 antibody or of a kinesin-1 heavy chain construct mutated in the motor domain, induced a dramatic increase in the size and reduction in number of substrate adhesions, mimicking the effect observed after microtubule disruption by nocodazole. Blockage of kinesin activity had no influence on either the ability of microtubules to target substrate adhesions or on microtubule polymerisation dynamics. We conclude that conventional kinesin is not required for the guidance of microtubules into substrate adhesions, but is required for the focal delivery of a component(s) that retards their growth or promotes their disassembly.

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Berman, J. E., et S. Zolla-Pazner. « Control of B cell proliferation : arrest of B cells in late G1 underlies immunosuppression induced by plasma cell tumors. » Journal of Immunology 138, n^o 9 (1 mai 1987) : 2805–12. http://dx.doi.org/10.4049/jimmunol.138.9.2805.

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Abstract Immunosuppression in mice bearing plasma cell tumors (PC-mice) provides a model system for the study of negative B cell regulation. Our previous studies demonstrated that B cell proliferation is suppressed in these mice by a cascade of interactions involving macrophages and soluble factors. The present report pinpoints the G1 phase of the cell cycle as the stage of B cell proliferation inhibited in PC-mice. Modulation of surface immunoglobulin (sIg) with anti-mu, an early membrane activation event, occurred normally on B cells from the spleens of PC-mice. However, examination of the size profile and the expression of sIgD and sIgM on B cells from the spleens of PC-mice showed an accumulation of large-sized, low intensity sIgD+ cells, suggesting a block in B cell activation in the late G1 phase of the cell cycle. This was confirmed by experiments in vitro that demonstrated that although LPS-stimulated B cells from the spleens of PC-mice enlarged to a size characteristic of G1 phase, most did not additionally enlarge into S phase even after 3 days of culture, nor did they incorporate significant amounts of [3H]thymidine. Additional confirmation of a block in late G1 was obtained by using analysis of [3H]thymidine incorporation, cell size, and cell cycle after normal cells were cultured in supernatants from cloned PC lines containing the factor(s) that initiates the cascade of events leading to suppression of B cell proliferation. The relevance of these findings to PC-induced immunosuppression and to the regulation of normal B cell proliferation during the G1 phase of the cell cycle is discussed.

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Wang, Junjie, Meiyun Ma, Silviu Locovei, Robert W. Keane et Gerhard Dahl. « Modulation of membrane channel currents by gap junction protein mimetic peptides : size matters ». American Journal of Physiology-Cell Physiology 293, n^o 3 (septembre 2007) : C1112—C1119. http://dx.doi.org/10.1152/ajpcell.00097.2007.

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Connexin mimetic peptides are widely used to assess the contribution of nonjunctional connexin channels in several processes, including ATP release. These peptides are derived from various connexin sequences and have been shown to attenuate processes downstream of the putative channel activity. Yet so far, no documentation of effects of peptides on connexin channels has been presented. We tested several connexin and pannexin mimetic peptides and observed attenuation of channel currents that is not compatible with sequence specific actions of the peptides. Connexin mimetic peptides inhibited pannexin channel currents but not the currents of the channel formed by connexins from which the sequence was derived. Pannexin mimetic peptides did inhibit pannexin channel currents but also the channels formed by connexin 46. The same pattern of effects was observed for dye transfer, except that the inhibition levels were more pronounced than for the currents. The channel inhibition by peptides shares commonalities with channel effects of polyethylene glycol (PEG), suggesting a steric block as a mechanism. PEG accessibility is in the size range expected for the pore of innexin gap junction channels, consistent with a functional relatedness of innexin and pannexin channels.

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Beardsley, Robert M., Cintia S. De Paiva, David F. Power et Stephen C. Pflugfelder. « Desiccating Stress Decreases Apical Corneal Epithelial Cell Size-Modulation by the Metalloproteinase Inhibitor Doxycycline ». Cornea 27, n^o 8 (septembre 2008) : 935–40. http://dx.doi.org/10.1097/ico.0b013e3181757997.

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Reitsamer, Herbert A., Renate Pflug, Melchior Franz et Sonja Huber. « Dopaminergic modulation of horizontal-cell-axon-terminal receptive field size in the mammalian retina ». Vision Research 46, n^o 4 (février 2006) : 467–74. http://dx.doi.org/10.1016/j.visres.2005.05.010.

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Lixenberg, Adi, Merav Yarkoni, Yehudit Botschko et Mati Joshua. « Encoding of eye movements explains reward-related activity in cerebellar simple spikes ». Journal of Neurophysiology 123, n^o 2 (1 février 2020) : 786–99. http://dx.doi.org/10.1152/jn.00363.2019.

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The cerebellum exhibits both motor and reward-related signals. However, it remains unclear whether reward is processed independently from the motor command or might reflect the motor consequences of the reward drive. To test how reward-related signals interact with sensorimotor processing in the cerebellum, we recorded Purkinje cell simple spike activity in the cerebellar floccular complex while monkeys were engaged in smooth pursuit eye movement tasks. The color of the target signaled the size of the reward the monkeys would receive at the end of the target motion. When the tracking task presented a single target, both pursuit and neural activity were only slightly modulated by the reward size. The reward modulations in single cells were rarely large enough to be detected. These modulations were only significant in the population analysis when we averaged across many neurons. In two-target tasks where the monkey learned to select based on the size of the reward outcome, both behavior and neural activity adapted rapidly. In both the single- and two-target tasks, the size of the reward-related modulation matched the size of the effect of reward on behavior. Thus, unlike cortical activity in eye movement structures, the reward-related signals could not be dissociated from the motor command. These results suggest that reward information is integrated with the eye movement command upstream of the Purkinje cells in the floccular complex. Thus reward-related modulations of the simple spikes are akin to modulations found in motor behavior and not to the central processing of the reward value. NEW & NOTEWORTHY Disentangling sensorimotor and reward signals is only possible if these signals do not completely overlap. We recorded activity in the floccular complex of the cerebellum while monkeys performed tasks designed to separate representations of reward from those of movement. Activity modulation by reward could be accounted for by the coding of eye movement parameters, suggesting that reward information is already integrated into motor commands upstream of the floccular complex.

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Wen, Kunwen, Lifang Huang, Qi Wang et Jianshe Yu. « Modulation of first-passage time for gene expression via asymmetric cell division ». International Journal of Biomathematics 12, n^o 05 (juillet 2019) : 1950052. http://dx.doi.org/10.1142/s1793524519500529.

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How to balance the size of exponentially growing cells has always been a focus of biologists. Recent experiments have uncovered that the cell is divided into two daughter cells only when the level of time-keeper protein reaches a fixed threshold and cell division in prokaryote is not completely symmetric. The timing of cell division is essentially random because gene expression is stochastic, but cells seen to manage to have precise timing of cell division events. Although the inter-cellular variability of gene expression has attracted much attention, the randomness of event timing has been rarely studied. In our analysis, the timing of cell division is formulated as the first-passage time (denoted by FPT) for time-keeper protein’s level to cross a critical threshold firstly, we derive exact analytical formulae for the mean and noise of FPT based on stochastic gene expression model with asymmetric cell division. The results of numerical simulation show that the regulatory factors (division rate, newborn cell size, exponential growth rate and threshold) have significant influence on the mean and noise of FPT. We also show that both the increase of division rate and newborn cell size could reduce the mean of FPT and increase the noise of FPT, the larger the exponential growth rate is, the smaller the mean and noise of FPT will be; and the larger the threshold value is, the higher the mean of FPT is and the lower the noise is. In addition, compared with symmetric division, asymmetric division can reduce the mean of FPT and improve the noise of FPT. In summary, our results provide insight into the relationship between regulatory factors and FPT and reveal that asymmetric division is an effective mechanism to shorten the mean of FPT.

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Elding-Pontén, M., L. Stenberg, S. Lidin, G. Madariaga et J. M. Pérez-Mato. « Structure of Mn8Sn5 ». Acta Crystallographica Section B Structural Science 53, n^o 3 (1 juin 1997) : 364–72. http://dx.doi.org/10.1107/s0108768197000682.

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The title compound crystallizes as a slightly incommensurate modulation of the B8-type structure. In a basic NiAs structure, ∼60% of the trigonal pyramidal interstices are filled with Mn atoms in an ordered manner. The highest corresponding commensurate space group is Pbnm (Pnma, No. 62) with the cell parameters a = 21.9114 (4), b: 7.6003 (5), c = 5.5247 (5) Å. The four-dimensional superspace group of the incommensurate structure is Cmcm(α00)0s0 (No. 63.8), with the conventional setting Amam(00γ)0s0. The cell parameters for this incommensurate cell are a = 382 (1), b = 7.600 (2), c = 5.525 (2) Å, q = [0.616 (5), 0, 0]. The structural refinements were carried out on a multiply twinned specimen. The R-factors were 0.037 for the incommensurate refinement and 0.046 for one commensurate approximation. The refinements unambiguously show that the modulation is caused by the step-like modulation of one Mn site, which is accompanied by small displacive modulations of the basic lattice. The incommensurate nature of the modulation is manifested in a slight splitting of fifth-order satellites, visible in electron diffraction.

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Jin, Meiyan, et Daniel J. Klionsky. « Regulation of autophagy : Modulation of the size and number of autophagosomes ». FEBS Letters 588, n^o 15 (10 juin 2014) : 2457–63. http://dx.doi.org/10.1016/j.febslet.2014.06.015.

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Li, Haichun, Kai Jin, Man Luo, Xuejun Wang, Xiaowen Zhu, Xianping Liu, Ting Jiang, Qin Zhang, Sheng Wang et Zhiqing Pang. « Size Dependency of Circulation and Biodistribution of Biomimetic Nanoparticles : Red Blood Cell Membrane-Coated Nanoparticles ». Cells 8, n^o 8 (13 août 2019) : 881. http://dx.doi.org/10.3390/cells8080881.

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Recently, biomimetic nanoparticles, especially cell membrane-cloaked nanoparticles, have attracted increasing attention in biomedical applications, including antitumor therapy, detoxification, and immune modulation, by imitating the structure and the function of biological systems such as long circulation life in the blood. However, the circulation time of cell membrane-cloaked nanoparticles is far less than that of the original cells, greatly limiting their biomedical applications, while the underlying reasons are seldom demonstrated. In this study, the influence of particle size on the circulation and the biodistribution of red blood cell membrane-coated nanoparticles (RBC-NPs) as model biomimetic nanoparticles were investigated. Differently sized RBC-NPs (80, 120, 160, and 200 nm) were prepared by fusing RBC membranes on poly(lactic-co-glycolic acid) nanoparticles. It was shown that the particle size did not change the cellular uptake of these biomimetic nanoparticles by macrophage cells in vitro and their immunogenic responses in vivo. However, their circulation life in vivo decreased with the particle size, while their accumulation in the liver increased with the particle size, which might be related to their size-dependent filtration through hepatic sinusoids. These findings will provide experimental evidence for the design and the optimization of biomimetic nanoparticles.

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González-Mariscal, Lorenza, Helios Gallego-Gutiérrez, Laura González-González et Christian Hernández-Guzmán. « ZO-2 Is a Master Regulator of Gene Expression, Cell Proliferation, Cytoarchitecture, and Cell Size ». International Journal of Molecular Sciences 20, n^o 17 (24 août 2019) : 4128. http://dx.doi.org/10.3390/ijms20174128.

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ZO-2 is a cytoplasmic protein of tight junctions (TJs). Here, we describe ZO-2 involvement in the formation of the apical junctional complex during early development and in TJ biogenesis in epithelial cultured cells. ZO-2 acts as a scaffold for the polymerization of claudins at TJs and plays a unique role in the blood–testis barrier, as well as at TJs of the human liver and the inner ear. ZO-2 movement between the cytoplasm and nucleus is regulated by nuclear localization and exportation signals and post-translation modifications, while ZO-2 arrival at the cell border is triggered by activation of calcium sensing receptors and corresponding downstream signaling. Depending on its location, ZO-2 associates with junctional proteins and the actomyosin cytoskeleton or a variety of nuclear proteins, playing a role as a transcriptional repressor that leads to inhibition of cell proliferation and transformation. ZO-2 regulates cell architecture through modulation of Rho proteins and its absence induces hypertrophy due to inactivation of the Hippo pathway and activation of mTOR and S6K. The interaction of ZO-2 with viral oncoproteins and kinases and its silencing in diverse carcinomas reinforce the view of ZO-2 as a tumor regulator protein.

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Hayes, Polly, Vladimir Varga, Sofia Olego-Fernandez, Jack Sunter, Michael L. Ginger et Keith Gull. « Modulation of a cytoskeletal calpain-like protein induces major transitions in trypanosome morphology ». Journal of Cell Biology 206, n^o 3 (4 août 2014) : 377–84. http://dx.doi.org/10.1083/jcb.201312067.

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Individual eukaryotic microbes, such as the kinetoplastid parasite Trypanosoma brucei, have a defined size, shape, and form yet transition through life cycle stages, each having a distinct morphology. In questioning the structural processes involved in these transitions, we have identified a large calpain-like protein that contains numerous GM6 repeats (ClpGM6) involved in determining T. brucei cell shape, size, and form. ClpGM6 is a cytoskeletal protein located within the flagellum along the flagellar attachment zone (FAZ). Depletion of ClpGM6 in trypomastigote forms produces cells with long free flagella and a shorter FAZ, accompanied by repositioning of the basal body, the kinetoplast, Golgi, and flagellar pocket, reflecting an epimastigote-like morphology. Hence, major changes in microbial cell form can be achieved by simple modulation of one or a few proteins via coordinated association and positioning of membrane and cytoskeletal components.

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Zhen, Cheng, Xinguo Hua, Xue Jiang, Guimin Tong, Chunming Li, Chuanping Yang et Yuxiang Cheng. « Cas9/gRNA-Mediated Mutations in PtrFLA40 and PtrFLA45 Reveal Redundant Roles in Modulating Wood Cell Size and SCW Synthesis in Poplar ». International Journal of Molecular Sciences 24, n^o 1 (27 décembre 2022) : 427. http://dx.doi.org/10.3390/ijms24010427.

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Fasciclin-like arabinogalactan proteins (FLAs) play an important role in plant development and adaptation to the environment. However, the roles of FLAs in wood formation remain poorly understood. Here, we identified a total of 50 PtrFLA genes in poplar. They were classified into four groups: A to D, among which group A was the largest group with 28 members clustered into four branches. Most PtrFLAs of group A were dominantly expressed in developing xylem based on microarray and RT-qPCR data. The roles of PtrFLA40 and PtrFLA45 in group A were investigated via the Cas9/gRNA-induced mutation lines. Loss of PtrFLA40 and PtrFLA45 increased stem length and diameter in ptrfla40ptrfla45 double mutants, but not in ptrfla40 or ptrfla45 single mutants. Further, our findings indicated that the ptrfla40ptrfla45 mutants enlarged the cell size of xylem fibers and vessels, suggesting a negative modulation in stem xylem cell size. In addition, wood lignin content in the ptrfla40fla45 mutants was increased by nearly 9%, and the lignin biosynthesis-related genes were significantly up-regulated in the ptrfla40fla45 mutants, in agreement with the increase in wood lignin content. Overall, Cas9/gRNA-mediated mutations in PtrFLA40 and PtrFLA45 reveal redundant roles in modulating wood cell size and secondary cell wall (SCW) synthesis in poplar.

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Wagner, M. B., D. Golod, R. Wilders, E. E. Verheijck, R. W. Joyner, R. Kumar, H. J. Jongsma, A. C. Van Ginneken et W. N. Goolsby. « Modulation of propagation from an ectopic focus by electrical load and by extracellular potassium ». American Journal of Physiology-Heart and Circulatory Physiology 272, n^o 4 (1 avril 1997) : H1759—H1769. http://dx.doi.org/10.1152/ajpheart.1997.272.4.h1759.

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We previously developed a technique (R. Kumar, R. Wilders, R. W. Joyner, H. J. Jongsma, E. E. Verheijck, D. A. Golod, A. C. G. van Ginneken, and W. N. Goolsby. Circulation 94: 833-841, 1996) for study of a mathematical model cell with spontaneous activity, viz. a "real-time" simulation of a rabbit sinoatrial node cell (SAN model cell; R. Wilders, H. J. Jongsma, and A. C. van Ginneken. Biophys. J. 60: 1202-1216, 1991) simultaneously being electrically coupled via our "coupling clamp" [H. Sugiura and R. W. Joyner. Am. J. Physiol. 263 (Heart Circ. Physiol. 32): H1591-H1604, 1992] circuit to a real, isolated ventricular myocyte. We now apply this technique to investigate effects of coupling conductance (Gc), cell size, and the modulation of membrane potential by elevated extracellular potassium concentration on the ability of an ectopic focus, represented by the SAN model cell, to successfully drive a ventricular cell. Values of Gc and the relative sizes of the two cells define three possible outcomes: 1) spontaneous pacing of the SAN model cell but not driving of the ventricular cell, 2) cessation of spontaneous pacing, or 3) pacing of the SAN model cell and driving of the ventricular cell. Below a critical size of the SAN model cell only the first two of these outcomes is possible. Above this critical size there is a range of Gc that allows successful operation of the system as an ectopic focus. Elevation of extracellular potassium concentration from 4 to 8 mM increases both the lower bound and upper bound of Gc for this range. Elevation of extracellular potassium concentration, as commonly observed in myocardial ischemia, may have effects on either inhibiting or releasing from inhibition an ectopic focus.

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Fan, Xiujun, Shanmugam Muruganandan, Philemon D. Shallie, Sabita Dhal, Matthew Petitt et Nihar R. Nayak. « VEGF Maintains Maternal Vascular Space Homeostasis in the Mouse Placenta through Modulation of Trophoblast Giant Cell Functions ». Biomolecules 11, n^o 7 (20 juillet 2021) : 1062. http://dx.doi.org/10.3390/biom11071062.

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Vascular endothelial growth factor (VEGF) is an angiogenic growth factor that acts primarily on endothelial cells, but numerous studies suggest that VEGF also acts on non-endothelial cells, including trophoblast cells. Inhibition of VEGF signaling by excess production of the endogenous soluble VEGF receptor sFlt1 in trophoblast cells has been implicated in several pregnancy complications. Our previous studies and other reports have shown that VEGF directly regulates placental vascular development and functions and that excess VEGF production adversely affects placental vascular development. Trophoblast giant cells (TGCs) line the maternal side of the placental vasculature in mice and function like endothelial cells. In this study, we specifically examined the effect of excess VEGF signaling on TGC development associated with defective placental vascular development using two mouse models an endometrial VEGF overexpression model and a placenta-specific sFlt1 knockdown model. Placentas of endometrial VEGF-overexpressing dams at embryonic days (E) 11.5 and 14.5 showed dramatic enlargement of the venous maternal spaces in junctional zones. The size and number of the parietal TGCs that line these venous spaces in the placenta were also significantly increased. Although junctional zone venous blood spaces from control and VEGF-overexpressing dams were not markedly different in size at E17.5, the number and size of P-TGCs were both significantly increased in the placentas from VEGF-overexpressing dams. In sFlt1 knockdown placentas, however, there was a significant increase in the size of the sinusoidal TGC-lined, alkaline phosphatase-positive maternal blood spaces in the labyrinth. These results suggest that VEGF signaling plays an important role in maintaining the homeostasis of the maternal vascular space in the mouse placenta through modulation of TGC development and differentiation, similar to the effect of VEGF on endothelial cells in other vascular beds.

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Rizzi, Federica, Rachele Castaldo, Tiziana Latronico, Pierluigi Lasala, Gennaro Gentile, Marino Lavorgna, Marinella Striccoli et al. « High Surface Area Mesoporous Silica Nanoparticles with Tunable Size in the Sub-Micrometer Regime : Insights on the Size and Porosity Control Mechanisms ». Molecules 26, n^o 14 (13 juillet 2021) : 4247. http://dx.doi.org/10.3390/molecules26144247.

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Mesoporous silica nanostructures (MSNs) attract high interest due to their unique and tunable physical chemical features, including high specific surface area and large pore volume, that hold a great potential in a variety of fields, i.e., adsorption, catalysis, and biomedicine. An essential feature for biomedical application of MSNs is limiting MSN size in the sub-micrometer regime to control uptake and cell viability. However, careful size tuning in such a regime remains still challenging. We aim to tackling this issue by developing two synthetic procedures for MSN size modulation, performed in homogenous aqueous/ethanol solution or two-phase aqueous/ethyl acetate system. Both approaches make use of tetraethyl orthosilicate as precursor, in the presence of cetyltrimethylammonium bromide, as structure-directing agent, and NaOH, as base-catalyst. NaOH catalyzed syntheses usually require high temperature (>80 °C) and large reaction medium volume to trigger MSN formation and limit aggregation. Here, a successful modulation of MSNs size from 40 up to 150 nm is demonstrated to be achieved by purposely balancing synthesis conditions, being able, in addition, to keep reaction temperature not higher than 50 °C (30 °C and 50 °C, respectively) and reaction mixture volume low. Through a comprehensive and in-depth systematic morphological and structural investigation, the mechanism and kinetics that sustain the control of MSNs size in such low dimensional regime are defined, highlighting that modulation of size and pores of the structures are mainly mediated by base concentration, reaction time and temperature and ageing, for the homogenous phase approach, and by temperature for the two-phase synthesis. Finally, an in vitro study is performed on bEnd.3 cells to investigate on the cytotoxicity of the MNSs.

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Faivre-Fiorina, Béatrice, Alexis Caron, Céline Fassot, Isabelle Fries, Patrick Menu, Pierre Labrude et Claude Vigneron. « Presence of hemoglobin inside aortic endothelial cells after cell-free hemoglobin administration in guinea pigs ». American Journal of Physiology-Heart and Circulatory Physiology 276, n^o 2 (1 février 1999) : H766—H770. http://dx.doi.org/10.1152/ajpheart.1999.276.2.h766.

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The endothelium is the production site of several potent vasoactive factors that contribute to the modulation of the vascular tone. Because hemoglobin-based oxygen carriers (HBOC) have been demonstrated to cause vasoconstriction and thereby increase arterial pressure by interacting with endothelium-derived factors such as nitric oxide and endothelin-1, we hypothesized that hemoglobin could penetrate into the endothelial cells. Therefore, we investigated the presence of hemoglobin into guinea pig aortic endothelial cells by immunohistochemical staining after exchange transfusion with a hemoglobin-based oxygen carrier. Despite the large molecular size of HBOC due to chemical modifications designed to prevent hemoglobin subunit dissociation and extravascular leakage, hemoglobin was detectable by immunohistochemical staining into the endothelial cells. These findings suggest that the vascular endothelial cells could uptake hemoglobin by endocytosis mechanisms or could help hemoglobin to cross the endothelial barrier toward media by transcytosis mechanisms. These findings are very important to lead future investigations to the mechanisms by which HBOC cause vasoconstriction.

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Ziętara, Natalia, Marcin Łyszkiewicz, Andreas Krueger et Siegfried Weiss. « B-cell modulation of dendritic-cell function : Signals from the far side ». European Journal of Immunology 44, n^o 1 (janvier 2014) : 23–32. http://dx.doi.org/10.1002/eji.201344007.

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Mank, A. J. G., H. de Nijs, H. Lingeman, U. A. Th Brinkman, N. H. Velthorst et C. Gooijer. « Diode Laser-Based Absorption Detector for Conventional-Size Liquid Chromatography ». Applied Spectroscopy 50, n^o 1 (janvier 1996) : 28–34. http://dx.doi.org/10.1366/0003702963906681.

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A diode laser-based absorption detector is designed for conventional-size liquid chromatography (LC). To this end, various detection setups and individual components have been evaluated. A ratioing system using a 10-mW 670-nm diode laser allowed the detection of 6 × 10−10 M mitoxantrone [signal-to-noise (S/N) = 3; N = root-mean-square (rms) noise], an anti-tumor drug, in a biological matrix without any sample cleanup. Multipass detection and intensity modulation of the excitation light did not improve the detection limit. A fiber-optic detector cell, utilizing a gradient-index lens on the light-guiding fiber, was a good and robust alternative for the standard absorption detector cell. Detection limits with the use of the diode laser-based detector are 20-fold better than those obtained with a commercial absorption detector for LC.

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Gregory, T. Ryan, et Paul D. N. Hebert. « The Modulation of DNA Content : Proximate Causes and Ultimate Consequences ». Genome Research 9, n^o 4 (1 avril 1999) : 317–24. http://dx.doi.org/10.1101/gr.9.4.317.

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The forces responsible for modulating the large-scale features of the genome remain one of the most difficult issues confronting evolutionary biology. Although diversity in chromosomal architecture, nucleotide composition, and genome size has been well documented, there is little understanding of either the evolutionary origins or impact of much of this variation. The 80,000-fold divergence in genome sizes among eukaryotes represents perhaps the greatest challenge for genomic holists. Although some researchers continue to characterize much variation in genome size as a mere by-product of an intragenomic selfish DNA “free-for-all” there is increasing evidence for the primacy of selection in molding genome sizes via impacts on cell size and division rates. Moreover, processes inducing quantum or doubling series variation in gametic or somatic genome sizes are common. These abrupt shifts have broad effects on phenotypic attributes at both cellular and organismal levels and may play an important role in explaining episodes of rapid—or even saltational—character state evolution.

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Zhang, Jiqian, Chuansheng Shen et Zhifeng Cui. « Modulation on the collective response behavior by the system size in two-dimensional coupled cell systems ». Science in China Series G 49, n^o 3 (juin 2006) : 304–12. http://dx.doi.org/10.1007/s11433-006-0304-z.

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Linton, Paul. « Does Vergence Affect Perceived Size ? » Vision 5, n^o 3 (22 juin 2021) : 33. http://dx.doi.org/10.3390/vision5030033.

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Since Kepler (1604) and Descartes (1637), it has been suggested that ‘vergence’ (the angular rotation of the eyes) plays a key role in size constancy. However, this has never been tested divorced from confounding cues such as changes in the retinal image. In our experiment, participants viewed a target which grew or shrank in size over 5 s. At the same time, the fixation distance specified by vergence was reduced from 50 to 25 cm. The question was whether this change in vergence affected the participants’ judgements of whether the target grew or shrank in size? We found no evidence of any effect, and therefore no evidence that eye movements affect perceived size. If this is correct, then our finding has three implications. First, perceived size is much more reliant on cognitive influences than previously thought. This is consistent with the argument that visual scale is purely cognitive in nature (Linton, 2017; 2018). Second, it leads us to question whether the vergence modulation of V1 contributes to size constancy. Third, given the interaction between vergence, proprioception, and the retinal image in the Taylor illusion, it leads us to ask whether this cognitive approach could also be applied to multisensory integration.

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Felmy, Felix. « Modulation of Cargo Release from Dense Core Granules by Size and Actin Network ». Traffic 8, n^o 8 (16 mai 2007) : 983–97. http://dx.doi.org/10.1111/j.1600-0854.2007.00583.x.

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Ma, Ruiqi, Qian Li, Zhongfeng Wang, Yifei Yuan, Lu Gan et Jiang Qian. « Modulation of hyaluronan polymer size regulates proliferation of perimysial fibroblasts in thyroid eye disease ». Biochemical and Biophysical Research Communications 496, n^o 4 (février 2018) : 1376–81. http://dx.doi.org/10.1016/j.bbrc.2018.02.037.

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Zhang, Wei-Cai, Mei-Ling Zheng, Jie Liu, Feng Jin, Xian-Zi Dong, Min Guo et Teng Li. « Modulation of Cell Behavior by 3D Biocompatible Hydrogel Microscaffolds with Precise Configuration ». Nanomaterials 11, n^o 9 (7 septembre 2021) : 2325. http://dx.doi.org/10.3390/nano11092325.

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Three-dimensional (3D) micronano structures have attracted much attention in tissue engineering since they can better simulate the microenvironment in vivo. Two-photon polymerization (TPP) technique provides a powerful tool for printing arbitrary 3D structures with high precision. Here, the desired 3D biocompatible hydrogel microscaffolds (3D microscaffold) with structure design referring to fibroblasts L929 have been fabricated by TPP technology, particularly considering the relative size of cell seed (cell suspension), spread cell, strut and strut spacing of scaffold. Modulation of the cell behavior has been studied by adjusting the porosity from 69.7% to 89.3%. The cell culture experiment results reveal that the obvious modulation of F-actin can be achieved by using the 3D microscaffold. Moreover, cells on 3D microscaffolds exhibit more lamellipodia than those on 2D substrates, and thus resulting in a more complicated 3D shape of single cell and increased cell surface. 3D distribution can be also achieved by employing the designed 3D microscaffold, which would effectively improve the efficiency of information exchange and material transfer. The proposed protocol enables us to better understand the cell behavior in vivo, which would provide high prospects for the further application in tissue engineering.

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Turlej, Eliza, Tomasz Marek Goszczyński, Marek Drab, Beata Orzechowska, Magdalena Maciejewska, Joanna Banach et Joanna Wietrzyk. « The Impact of Exosomes/Microvesicles Derived from Myeloid Dendritic Cells Cultured in the Presence of Calcitriol and Tacalcitol on Acute B-Cell Precursor Cell Lines with MLL Fusion Gene ». Journal of Clinical Medicine 11, n^o 8 (15 avril 2022) : 2224. http://dx.doi.org/10.3390/jcm11082224.

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Vitamin D analogs (VDAs) may directly inhibit the growth of normal and malignant (derived from acute lymphoblastic leukemia (ALL)) B cells, as both types of cells express vitamin D receptor (VDR). We performed anti-proliferative, morphology tests and phenotyping to evaluate the sensitivity of monocytes and iDCs (immature myeloid-derived dendritic cells) on calcitriol and tacalcitol treatment, phenotyping, morphology, and size distribution measurement to determine the characteristics of microvesicles (MVs) and exosomes (EXs) derived from them and, finally, phenotyping and Elisa test to determine the effects of VDAs on modulation of the phenotype of B cells through extracellular vesicles (EVs) released by iDCs. Our results confirmed that both SC cells and iDCs were sensitive to the VDAs and showed altered surface expression of markers associated with monocyte differentiation, which was resulting in the phenotypic changes in EVs derived from them. We also showed that obtained EVs could change the morphology and phenotype of ALL-B-derived precursor cells in a different way, depending on their origin. The differential effect of VDAs on ALL-B cells, which was associated with increased or decreased expression of CD27, CD24, CD38, and CD23 expression, was observed. Hence, further studies to explain the modulation in the composition of EVs by VDAs are required.

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Aggarwal, Sudeepta, et Mark F. Pittenger. « Modulation of Immune Cell Responses by Human Mesenchymal Stem Cells. » Blood 104, n^o 11 (16 novembre 2004) : 1288. http://dx.doi.org/10.1182/blood.v104.11.1288.1288.

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Abstract Mesenchymal stem cells (hMSCs) are multipotent stem cells that have the capacity to differentiate into various lineages. These cells provide stromal support and can be utilized as a feeder layer for expansion of hematopoitic stem cells and embryonic stem cells. Furthermore, allo-transplanted MSCs are not rejected and have been shown to mediate immuno-modulatory functions in vitro. Also, MSCs have been found at the wound site at extended times. The mechanisms underlying MSC migration and immuno-modulation are still under investigation. Aim: To understand the factors involved in human MSC (hMSC) migration and their interaction with various immune cell types. Methods: Human MSCs were examined for the presence of cell surface receptors that may play a role in migration using quantitative RT-PCR. Next, hMSCs were co-cultured with purified immune cell types including dendritic cells (DCs), naïve T cells and NK cells. Following the co-culture, changes in the phenotype of the immune cells under activating conditions were analyzed using ELISA and functional assays. Results: Human MSCs express Toll receptors, especially TLR4, on their cell surface. The TLR4 on hMSCs is functional as seen by a several-fold increase in IL-6 and chemokine IL-8 upon incubation with TLR4 exogenous ligand lipopolysaccharide (LPS) and the endogenous ligand, soluble hyaluronic acid (sHA). When hMSCs were incubated with activated dendritic cells, there was a >50% decrease in TNF-α secretion and a >50% increase in IL-10 secretion. When hMSCs were incubated with naïve T cells, hMSCs decreased IFN-γ secretion and increased IL-4 secretion. Decreased IFN-γ was also seen when MSCs were incubated with NK cells. Conclusion: These results suggest that (i) hMSCs may respond to the signals generated by breakdown products of extracellular matrix (e.g. sHA) via TLR4 and assist in wound healing (ii) hMSCs immuno-modulatory effects are mediated by interacting with various immune cell types and altering their phenotypic response to a more tolerant and anti-inflammatory response.

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Di Marzo, Maurizio, Vívian Ebeling Viana, Camilla Banfi, Valeria Cassina, Roberta Corti, Humberto Herrera-Ubaldo, Nicola Babolin et al. « Cell wall modifications by α-XYLOSIDASE1 are required for control of seed and fruit size in Arabidopsis ». Journal of Experimental Botany 73, n^o 5 (25 novembre 2021) : 1499–515. http://dx.doi.org/10.1093/jxb/erab514.

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Abstract Cell wall modifications are of pivotal importance during plant development. Among cell wall components, xyloglucans are the major hemicellulose polysaccharide in primary cell walls of dicots and non-graminaceous monocots. They can connect the cellulose microfibril surface to affect cell wall mechanical properties. Changes in xyloglucan structure are known to play an important role in regulating cell growth. Therefore, the degradation of xyloglucan is an important modification that alters the cell wall. The α-XYLOSIDASE1 (XYL1) gene encodes the only α-xylosidase acting on xyloglucans in Arabidopsis thaliana. Here, we showed that mutation of XYL1 strongly influences seed size, seed germination, and fruit elongation. We found that the expression of XYL1 is directly regulated in developing seeds and fruit by the MADS-box transcription factor SEEDSTICK. We demonstrated that XYL1 complements the stk smaller seed phenotype. Finally, by atomic force microscopy, we investigated the role of XYL1 activity in maintaining cell stiffness and growth, confirming the importance of cell wall modulation in shaping organs.

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Bagri, Kayo, Luiz Fernando Oliveira, Miria Pereira, José Abreu et Claudia Mermelstein. « The Wnt/Beta-Catenin Pathway and Cytoskeletal Filaments Are Involved in the Positioning, Size, and Function of Lysosomes during Chick Myogenesis ». Cells 11, n^o 21 (27 octobre 2022) : 3402. http://dx.doi.org/10.3390/cells11213402.

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Lysosomes are highly dynamic organelles involved in the breakdown and recycling of macromolecules, cell cycle, cell differentiation, and cell death, among many other functions in eukaryotic cells. Recently, lysosomes have been identified as cellular hubs for the modulation of intracellular signaling pathways, such as the Wnt/beta-catenin pathway. Here we analyzed morphological and functional characteristics of lysosomes in muscle and non-muscle cells during chick myogenesis, as well as their modulation by the Wnt/beta-catenin pathway. Our results show that (i) muscle and non-muscle cells show differences in lysosomal size and its distribution, (ii) lysosomes are found in spherical structures in myoblasts and fibroblasts and tubular structures in myotubes, (iii) lysosomes are found close to the plasma membrane in fibroblasts and close to the nucleus in myoblasts and myotubes, (iv) lysosomal distribution and size are dependent on the integrity of microtubules and microfilaments in myogenic cells, (v) alterations in lysosomal function, in the expression of LAMP2, and in Wnt/beta-catenin pathway affect the distribution and size of lysosomes in myogenic cells, (vi) the effects of the knockdown of LAMP2 on myogenesis can be rescued by the activation of the Wnt/beta-catenin pathway, and (vii) the chloroquine Lys05 is a potent inhibitor of both the Wnt/beta-catenin pathway and lysosomal function. Our data highlight the involvement of the Wnt/beta-catenin pathway in the regulation of the positioning, size, and function of lysosomes during chick myogenesis.

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Alberghina, Lilia, Riccardo L. Rossi, Lorenzo Querin, Valeria Wanke et Marco Vanoni. « A cell sizer network involving Cln3 and Far1 controls entrance into S phase in the mitotic cycle of budding yeast ». Journal of Cell Biology 167, n^o 3 (1 novembre 2004) : 433–43. http://dx.doi.org/10.1083/jcb.200405102.

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Saccharomyces cerevisiae must reach a carbon source-modulated critical cell size, protein content per cell at the onset of DNA replication (Ps), in order to enter S phase. Cells grown in glucose are larger than cells grown in ethanol. Here, we show that an increased level of the cyclin-dependent inhibitor Far1 increases cell size, whereas far1Δ cells start bud emergence and DNA replication at a smaller size than wild type. Cln3Δ, far1Δ, and strains overexpressing Far1 do not delay budding during an ethanol glucose shift-up as wild type does. Together, these findings indicate that Cln3 has to overcome Far1 to trigger Cln–Cdc28 activation, which then turns on SBF- and MBF-dependent transcription. We show that a second threshold is required together with the Cln3/Far1 threshold for carbon source modulation of Ps. A new molecular network accounting for the setting of Ps is proposed.

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Scholl, Juliete Nathali, Amanda de Fraga Dias, Pauline Rafaela Pizzato, Daniela Vasconcelos Lopes, Cesar Eduardo Jacintho Moritz, Elisa Helena Farias Jandrey, Gabriele Dadalt Souto et al. « Characterization and antiproliferative activity of glioma-derived extracellular vesicles ». Nanomedicine 15, n^o 10 (avril 2020) : 1001–18. http://dx.doi.org/10.2217/nnm-2019-0431.

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Aim: To characterize a method to isolate glioma-derived extracellular vesicles (GEVs) and understand their role in immune system modulation and glioma progression. Materials & methods: GEVs were isolated by differential centrifugation from C6 cell supernatant and characterized by size and expression of CD9, HSP70, CD39 and CD73. The glioma model was performed by injecting C6 glioma cells into the right striatum of Wistar rats in the following groups: controls (C6 cells alone), coinjection (C6 cells + GEVs) and GEVs by intranasal administration followed by immune cells, tumor size and cells proliferation analyses. Results: GEVs presented uniform size (175 nm), expressed CD9, HSP70, CD39, CD73 and produced adenosine. In vivo, we observed a reduction in tumor size, in cell proliferation (Ki-67) and in a regulatory cell marker (FoxP3). Conclusion: GEVs, administered before or at tumor challenge, have antiproliferative properties and reduce regulatory cells in the glioma microenvironment.

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Arifin, Ibrahim, Farhana Farhana, Dwi Setyorini, Anis Fauzia et Dwi Nilawati. « The Effect of Grape Seed Extract and 5-Fluorouracil toward Apoptosis Induction and Cell Cycle Modulation ofWiDr Cells ». Journal of Chemical Process and Material Technology 1, n^o 2 (29 août 2022) : 18. http://dx.doi.org/10.36499/jcpmt.v1i2.7116.

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5-Fluorouracil is a commonly used chemotherapeutic agent in patients with colon cancer. The side effect using of 5-fluorouracil such as cardiotoxicity and immunosupressioncan lead to death. One of the approach to overcome overloaded use of 5-fluorouracil is the combination with a chemopreventive agent, including the grape seeds extract (Vitis vinifera L.). This research aims to reviewing the effect of grape seeds extract on the cytotoxic activity of 5-fluorouracil in modulating cell cycle and apoptosis induction of colon cancer cellsWiDr. Determination of the cytotoxic activity of grape seeds extract and 5-fluorouracil as well as a combination of both conducted by MTT assay. Modulation surveillance of cell cycle and apoptosis induction is done by using flowcytometry and analyzed by FACS Calibur program. Cytotoxicity assay single treatment of grape seeds extract (IC50) is 403,957μg/ml, whereas IC50 values 5-fluorouracil is 848 µM. Observations modulation of cell cycle and apoptosis induction combination of grape seeds extract and 5-fluorouracil at concentrations of 403,957μg/ml - 212 µM, showed that a combination of grape seeds extract and 5-fluorouracil to inhibit the proliferation of cells in S phase and able to induce apoptosis of colon cancer cells WiDr.Keywords: Grape seeds extract, 5-Fluorouracil, Cell cycle, Apoptosis, WiDr cells

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Candelas, Graciela C., Anselmo Ortiz et Nayda Ortiz. « Features of the cell-free translation of a spider fibroin mRNA ». Biochemistry and Cell Biology 67, n^o 2-3 (1 février 1989) : 173–76. http://dx.doi.org/10.1139/o89-026.

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The massive production of fibroin by the large ampullate glands of the spider, Nephila clavipes, serves as a model system in which to study the synthesis and control of a large secretory protein. Their tissue-specific product, fibroin, produced during the entire adult life of the female, is approximately 320 kilodaltons, and rich in glycine and alanine. Highly purified fibroin mRNA from the glands has been translated in a rabbit reticulocyte cell-free system with variable supplements. The translational products analyzed by SDS–PAGE display two features, tRNA modulation and discontinuous pauses during elongation. tRNA complements exert their effects both in the translational efficiency and in the size of the peptides generated. The pauses observed during translation generate subsets of smaller discrete peptides, visualized in the gels as ladders of variable relative intensities, appearing exclusively and concomitantly with the fibroin. Definitive linkage between the discrete peptides and fibroin synthesis process has been established by their selective labeling with specific radioactive amino acids.Key words: translation, tRNA modulation, fibroin, protein synthesis, cell-free synthesis.

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Rieck, Kristy, Kyle Bromma, Wonmo Sung, Aaron Bannister, Jan Schuemann et Devika Basnagge Chithrani. « Modulation of gold nanoparticle mediated radiation dose enhancement through synchronization of breast tumor cell population ». British Journal of Radiology 92, n^o 1100 (août 2019) : 20190283. http://dx.doi.org/10.1259/bjr.20190283.

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Objective: The incorporation of high atomic number materials such as gold nanoparticles (GNPs) into tumor cells is being tested to enhance the local radiotherapy (RT) dose. It is also known that the radiosensitivity of tumor cells depends on the phase of their cell cycle. Triple combination of GNPs, phase of tumor cell population, and RT for improved outcomes in cancer treatment. Methods: We used a double-thymidine block method for synchronization of the tumor cell population. GNPs of diameters 17 and 46 nm were used to capture the size dependent effects. A radiation dose of 2 Gy with 6 MV linear accelerator was used to assess the efficacy of this proposed combined treatment. A triple negative breast cancer cell line, MDA-MB-231 was chosen as the model cell line. Monte Carlo (MC) calculations were done to predict the GNP-mediated cell death using the experimental GNP uptake data. Results: There was a 1.5- and 2- fold increase in uptake of 17 and 46 nm GNPs in the synchronized cell population, respectively. A radiation dose of 2 Gy with clinically relevant 6 MV photons resulted in a 62 and 38 % enhancement in cell death in the synchronized cell population with the incorporation of 17 and 46 nm GNPs, respectively. MC data supported the experimental data, but to a lesser extent. Conclusion: A triple combination of GNPs, cell cycle synchronization, and RT could pave the way to enhance the local radiation dose while minimizing side effects to the surrounding healthy tissue. Advances in knowledge: This is the first study to show that the combined use of GNPs, phase of tumor cell population, and RT could enhance tumor cell death.

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BURKHARDT, DWIGHT A., PATRICK K. FAHEY et MICHAEL A. SIKORA. « Retinal bipolar cells : Contrast encoding for sinusoidal modulation and steps of luminance contrast ». Visual Neuroscience 21, n^o 6 (novembre 2004) : 883–93. http://dx.doi.org/10.1017/s095252380421608x.

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Contrast encoding for sinusoidal modulations of luminance contrast was investigated by intracellular recording in the intact salamander retina. In what appears to be the first study of this kind for vertebrate bipolar cells, responses of the central receptive-field mechanism of cone-driven cells to modulation of 3 Hz were analyzed quantitatively via both signal averaging and a Fast Fourier Transform (FFT) while the retina was light adapted to 20 cd/m2. Depolarizing and hyperpolarizing bipolar cells showed very similar encoding. Both responded with sinusoidal waveforms whose amplitude varied linearly with modulation depths ranging up to 7–8%. The slope of the modulation/response curve was very steep in this range. Thus, the contrast gain was high, reaching values of 6–7, and the half-maximal response was achieved at modulations of 9% or less. At modulations above ∼15%, the responses typically showed strong compressive nonlinearity and the waveform was increasingly distorted. At maximum modulation, the higher harmonics of the FFT constituted about 30% of the amplitude of the fundamental. Measurements were also made for cones and horizontal cells. Both cell types showed predominantly linear responses and low contrast gain, in marked contrast to bipolar cells. These results suggest that the high contrast gain and strong nonlinearity of bipolar cells largely arise postsynaptic to cone transmitter release. Further experiments were performed to compare responses to contrast steps versus those to sinusoidal modulation. In the linear range, we show that the contrast gains of cones and horizontal cells are low and virtually identical for both steps and sinusoidal modulations. In bipolar cells, on the other hand, the contrast gain is about two times greater for steps than that for the 3-Hz sine waves. These results suggest that mechanisms intrinsic to bipolar cells act like a high-pass filter with a short time constant to selectively emphasize contrast transients over slower changes in contrast.

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Iritani, B. M. « Modulation of T-lymphocyte development, growth and cell size by the Myc antagonist and transcriptional repressor Mad1 ». EMBO Journal 21, n^o 18 (16 septembre 2002) : 4820–30. http://dx.doi.org/10.1093/emboj/cdf492.

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Sordella, Raffaella, Marie Classon, Kang-Quan Hu, Stephen F. Matheson, Madeleine R. Brouns, Barry Fine, Le Zhang, Hiroya Takami, Yoshihiko Yamada et Jeffrey Settleman. « Modulation of CREB Activity by the Rho GTPase Regulates Cell and Organism Size during Mouse Embryonic Development ». Developmental Cell 2, n^o 5 (mai 2002) : 553–65. http://dx.doi.org/10.1016/s1534-5807(02)00162-4.

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Kmita, Hanna, Małgorzata Budzińska et Olgierd Stobienia. « Modulation of the voltage-dependent anion-selective channel by cytoplasmic proteins from wild type and the channel depleted cells of Saccharomyces cerevisiae. » Acta Biochimica Polonica 50, n^o 2 (30 juin 2003) : 415–24. http://dx.doi.org/10.18388/abp.2003_3695.

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It is well known that effective exchange of metabolites between mitochondria and the cytoplasm is essential for cell physiology. The key step of the exchange is transport across the mitochondrial outer membrane, which is supported by the voltage-dependent anion-selective channel (VDAC). Therefore, it is clear that the permeability of VDAC must be regulated to adjust its activity to the actual cell needs. VDAC-modulating activities, often referred to as the VDAC modulator, were identified in the intermembrane space of different organism mitochondria but the responsible protein(s) has not been identified as yet. Because the VDAC modulator was reported to act on VDAC of intact mitochondria when added to the cytoplasmic side it has been speculated that a similar modulating activity might be present in the cytoplasm. To check the speculation we used mitochondria of the yeast Saccharomyces cerevisiae as they constitute a perfect model to study VDAC modulation. The mitochondria contain only a single isoform of VDAC and it is possible to obtain viable mutants devoid of the channel (Deltapor1). Moreover, we have recently characterised a VDAC-modulating activity located in the intermembrane space of wild type and Deltapor1 S. cerevisiae mitochondria. Here, we report that the cytoplasm of wild type and Deltapor1 cells of S. cerevisiae contains a VDAC-modulating activity as measured in a reconstituted system and with intact mitochondria. Since quantitative differences were observed between the modulating fractions isolated from wild type and Deltapor1 cells when they were studied with intact wild type mitochondria as well as by protein electrophoresis it might be concluded that VDAC may influence the properties of the involved cytoplasmic proteins. Moreover, the VDAC-modulating activity in the cytoplasm differs distinctly from that reported for the mitochondrial intermembrane space. Nevertheless, both these activities may contribute efficiently to VDAC regulation. Thus, the identification of the proteins is very important.

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