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Schmidt-Tanguy, Aline, Annette Romanski, Mathilde Hunault-Berger, and Oliver G. Ottmann. "Different Roles of Two Autotaxin Isoforms in Proliferation, Migration and Adhesion in the Non-Mutational Tyrosine Kinase Inhibitor Resistant Acute Lymphoblastic Leukemia Cell Line SupB15." Blood 112, no. 11 (November 16, 2008): 1915. http://dx.doi.org/10.1182/blood.v112.11.1915.1915.
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Abstract The Bcr-Abl oncogene is present in 30–40% of adult patients with acute lymphoblastic leukemia (ALL). The Abl kinase inhibitor imatinib-based therapy has become standard for this subset ALL. Acquired resistance to imatinib occurs frequently and is associated with mutations in the tyrosine kinase domain (TKD) approximately in about 80% of patients. In contrast, TKD mutations are uncommon in primary imatinib resistance which appears to be multifactorial, although the underlying mechanisms have been incompletely elucidated. We have established a Ph+ cell line for the analysis of non-mutational resistance mechanisms of imatinib resistance: SupB15RT, a Bcr-Abl expressing lymphoblastic cell line derived from SupB15WT cell line by gradually increasing the exposure to imatinib. SupB15RT shows cross-resistance to the second generation Abl kinase inhibitors Nilotinib and Dasatinib. We have shown that several commonly implicated mechanisms of imatinib resistance do not play a role in conferring the imatinib resistance in SupB15RT cells. By comparative gene expression analysis of SupB15WT vs. SupB15RT cells using Affymetrix- Microarrays, we identified 29 differentially regulated genes. Autotaxin (ATX) is one of the most highly up-regulated genes in imatinib resistant SupB15RT cells, and suggested a contribution to imatinib resistance. ATX is an exo-enzyme (pyrophosphophatase/phosphodiesterase). It plays a role in tumor progression and migration as a tumor cell autocrine motilty factor in various solid tumor cell types. ATX is involved in the synthesis of the signaling molecule, lysophosphatidic acid (LPA) which promotes survival and motility. It was the aim of this study to determine whereas ATX plays a functional role for imatinib resistance in Ph+ ALL. Using RT-PCR we demonstrated that 2 isoforms of ATX are expressed in SupB15RT cells: ATXshort and ATXlong. ATXlong (863 aa) contains highly basic insertion in the catalytic domain (52 residues). We retroviraly transfected BaF3 cells with p185 and/or ATXshort or ATXlong to analyze its influence on growth, adhesion and migration in mouse cell model. In comparison to wild type BaF3 cells the proliferation of BaF3 cells expressing ATXshort is enhanced (1,5-fold), whereas ATXlong expressing BaF3 cells showed no difference in proliferation in comparison to Mock infected cells. The proliferation of p185 expressing BaF3 cells co-expressing ATXshort or ATXlong is not inhibited by the treatment with 1μM imatinib after 3 days in contrast to p185 expressing BaF3 cells. In adhesion experiments, BaF3 cells expressing ATXshort showed a higher attachment independent of p185 expression. We also performed migration experiments using transwell assays. These assays showed more migration with cells co-expressing p185 and ATXlong compared to p185 alone. This is in agreement with our results for SupB15RT vs. SupB15WT with a 3-fold migration increase of SupB15RT. Application of 10% fetal calf serum (FCS) in migration experiments resulted in a 1,5-fold higher migration of the ATXlong expressing BaF3 cells compared to culture without FCS. One explanation for this finding may be that FCS contains lysophosphatidic choline (LPC) which is converted to LPA by ATX. Although expression of both 2 isoforms of ATX is important for the increased proliferation, it seems that the 2 isoforms have different cellular functions in Ph+ lymphoblastic cells. ATXshort seems to enhance adhesion whereas ATXlong plays an important role in motility. Taken together our results indicate a role for ATX in TK- inhibitor resistant SupB15RT cells through LPA signaling via LPA receptors. The ratio between ATXshort and ATXlong probably is important for the intracellular signaling and has to be explored.
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An, Xingyue, Gabrielle Romain, Melisa Martinez-Paniagua, Irfan N. Bandey, Jay R. T. Adolacion, Mohsen Fathi, Ivan Liadi, et al. "CAR+ T cell anti-tumor efficacy revealed by multi-dimensional single-cell profiling." Journal of Immunology 202, no. 1_Supplement (May 1, 2019): 134.2. http://dx.doi.org/10.4049/jimmunol.202.supp.134.2.
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Abstract T cells engineered to express chimeric antigen receptor (CAR) targeting CD19 have shown promising clinical responses in patients with certain hematologic malignancies, however, it is desirable to be able to enrich cells with enhanced anti-tumor efficacy prior to infusion. We utilized a suite of high-throughput technologies with single-cell resolution, including Timelapse Imaging Microscopy In Nanowell Grids (TIMING) that integrates cytokine profiling to reveal that persistent motility of CD19- specific CAR T cells is correlated to desirable polyfunctionality (elimination of tumor cells and cytokine secretion), contributing to anti-tumor effects. We implemented a marker-free Boyden chamber-based method to enrich CAR+ T cells with persistent motility (motile cell). Integration of transcriptomic profiling, immune phenotyping and metabolism demonstrated that motile cells are more naïve-like with higher oxidative metabolism and spare respiratory capacity. Our result also revealed that the master metabolic regulator AMP kinase (AMPK) is required for CAR+ T cells with high motility. We used a xenograft leukemia mouse model (CD19+ NALM-6) and validated that the motile cells have enhanced persistence and superior anti-cancer effect in vivo compared to the parental un-sorted population. Collectively, our multi-dimensional results demonstrated that persistent motility is a selectable biomarker of expanded CAR+ T cell bioactivity.
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Cramer, Louise P., Timothy J. Mitchison, and Julie A. Theriot. "Actin-dependent motile forces and cell motility." Current Opinion in Cell Biology 6, no. 1 (February 1994): 82–86. http://dx.doi.org/10.1016/0955-0674(94)90120-1.
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Murakami, Shinya, Yo Otsuka, Manabu Sugimoto, and Toshiyuki Mitsui. "3H1010 Controlled cell migration with ultrasound(Cell Biology III:Cytoskeleton & Motility,Oral Presentation)." Seibutsu Butsuri 52, supplement (2012): S70. http://dx.doi.org/10.2142/biophys.52.s70_4.
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Kolobov, A. V., A. A. Polezhaev, and G. I. Solyanik. "The Role of Cell Motility in Metastatic Cell Dominance Phenomenon: Analysis by a Mathematical Model." Journal of Theoretical Medicine 3, no. 1 (2000): 63–77. http://dx.doi.org/10.1080/10273660008833065.
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Metastasis is the outcome of several selective sequential steps where one of the first and necessary steps is the progressive overgrowth or dominance of a small number of metastatic cells in a tumour. In spite of numerous experimental investigations concerning the growth advantage of metastatic cells, the mechanisms resulting in their dominance are still unknown. Metastatic cell overgrowth occurs even if doubling time of the metastatic subpopulation is shorter than that of all others subpopulations in a heterogeneous tumour. In order to examine the hypothesis that under conditions of competition of cell subpopulations for common substrata cell motility of the slow-growing subpopulation can result in its dominance in a heterogeneous tumour, a mathematical model of heterogeneous tumour growth is suggested. The model describes two cell subpopulations which can grow with different rates and transform into the resting state depending on the concentration of the substrate consumed by both subpopulations. The slow-growing subpopulation is assumed to be motile. In numerical simulations it is shown that this subpopulation is able to overgrow the other one. The dominance phenomenon (resulting from random cell motion) depends on the motility coefficient in a threshold manner: in a heterogeneous tumour the slow-dividing motile subpopulation is able to overgrow its non-motile counterparts if its motility coefficient exceeds a certain threshold value. Computations demonstrate independence of the motile cells overgrowth from the initial tumour composition.
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Rezvan, Ali, Gabrielle Romain, Mohsen Fathi, Darren Heeke, Melisa Martinez-Paniagua, Xingyue An, Irfan N. Bandey, et al. "Multiomic dynamic single-cell profiling of CAR T cell populations associated with efficacy." Journal of Immunology 208, no. 1_Supplement (May 1, 2022): 54.18. http://dx.doi.org/10.4049/jimmunol.208.supp.54.18.
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Abstract T-cell therapy with specificity redirected through chimeric antigen receptors (CARs) has shown efficacy for the treatment of hematologic malignancies. Although treatment with CAR T cell can result in high response rates, the properties of the cells that comprise the cellular infusion product, associated with clinical benefit are incompletely understood. We utilized a suite of high-throughput single-cell assays including single-cell RNA-sequencing (scRNA-seq); confocal microscopy; and Timelapse Imaging Microscopy In Nanowell Grids (TIMING). TIMING profiling of a cohort of 16 patients showed that persistent motility of T cells in the presence of tumor cells was associated with both serial killing capacity and polyfunctionality. Confocal microscopy on these same T cells revealed that persistent motility is linearly correlated with both mitochondrial volume and lysosomal number. ScRNA-seq demonstrated that T cells from responders were enriched in pathways related to T-cell proliferative capacity; interferon responses; and a distinct cluster of pathways related to actin cytoskeleton and migration. We employed a marker-free sorting strategy for enriching T cells with persistent motility. RNA-seq on sorted motile T cells showed an enrichment of the core motility signature. These motile T cells also demonstrated superior in vivo anti-leukemia efficacy in comparison to unsorted T cells. Lastly, we also confirmed the association with increased persistent motility and killing of CAR T cells across diverse CARs. In aggregate, our data identified that independent of CAR design or biomanufacturing, persistent motility serves as a selectable cell-intrinsic biomarker, desired in the bioactivity of expanded CAR+ T cells.
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Marth, W., S. Praetorius, and A. Voigt. "A mechanism for cell motility by active polar gels." Journal of The Royal Society Interface 12, no. 107 (June 2015): 20150161. http://dx.doi.org/10.1098/rsif.2015.0161.
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We analyse a generic motility model, with the motility mechanism arising by contractile stress due to the interaction of myosin and actin. A hydrodynamic active polar gel theory is used to model the cytoplasm of a cell and is combined with a Helfrich-type model to account for membrane properties. The overall model allows consideration of the motility without the necessity for local adhesion. Besides a detailed numerical approach together with convergence studies for the highly nonlinear free boundary problem, we also compare the induced flow field of the motile cell with that of classical squirmer models and identify the motile cell as a puller or pusher, depending on the strength of the myosin–actin interactions.
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Breier, Rebekka E., Cristian C. Lalescu, Devin Waas, Michael Wilczek, and Marco G. Mazza. "Emergence of phytoplankton patchiness at small scales in mild turbulence." Proceedings of the National Academy of Sciences 115, no. 48 (November 8, 2018): 12112–17. http://dx.doi.org/10.1073/pnas.1808711115.
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Phytoplankton often encounter turbulence in their habitat. As most toxic phytoplankton species are motile, resolving the interplay of motility and turbulence has fundamental repercussions on our understanding of their own ecology and of the entire ecosystems they inhabit. The spatial distribution of motile phytoplankton cells exhibits patchiness at distances of decimeter to millimeter scales for numerous species with different motility strategies. The explanation of this general phenomenon remains challenging. Furthermore, hydrodynamic cell–cell interactions, which grow more relevant as the density in the patches increases, have been so far ignored. Here, we combine particle simulations and continuum theory to study the emergence of patchiness in motile microorganisms in three dimensions. By addressing the combined effects of motility, cell–cell interaction, and turbulent flow conditions, we uncover a general mechanism: The coupling of cell–cell interactions to the turbulent dynamics favors the formation of dense patches. Identification of the important length and time scales, independent from the motility mode, allows us to elucidate a general physical mechanism underpinning the emergence of patchiness. Our results shed light on the dynamical characteristics necessary for the formation of patchiness and complement current efforts to unravel planktonic ecological interactions.
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Alexandre, Gladys. "Chemotaxis Control of Transient Cell Aggregation." Journal of Bacteriology 197, no. 20 (July 27, 2015): 3230–37. http://dx.doi.org/10.1128/jb.00121-15.
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Chemotaxis affords motile cells the ability to rapidly respond to environmental challenges by navigating cells to niches favoring growth. Such a property results from the activities of dedicated signal transduction systems on the motility apparatus, such as flagella, type IV pili, and gliding machineries. Once cells have reached a niche with favorable conditions, they often stop moving and aggregate into complex communities termed biofilms. An intermediate and reversible stage that precedes commitment to permanent adhesion often includes transient cell-cell contacts between motile cells. Chemotaxis signaling has been implicated in modulating the transient aggregation of motile cells. Evidence further indicates that chemotaxis-dependent transient cell aggregation events are behavioral responses to changes in metabolic cues that temporarily prohibit permanent attachment by maintaining motility and chemotaxis. This minireview discusses a few examples illustrating the role of chemotaxis signaling in the initiation of cell-cell contacts in bacteria moving via flagella, pili, or gliding.
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Cozzolino, Mauro, Venturina Stagni, Laura Spinardi, Nadia Campioni, Carla Fiorentini, Erica Salvati, Stefano Alemà, and Anna Maria Salvatore. "p120 Catenin Is Required for Growth Factor–dependent Cell Motility and Scattering in Epithelial Cells." Molecular Biology of the Cell 14, no. 5 (May 2003): 1964–77. http://dx.doi.org/10.1091/mbc.e02-08-0469.
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Cadherin-mediated cell–cell adhesion is dynamically modulated during epithelial–mesenchymal transition triggered by activation of receptor tyrosine kinases (RTK) in epithelial cells. Several cadherin-binding proteins have been identified that control cell–cell adhesion. However, the mechanisms by which intercellular adhesion and cell motility are coregulated are still unknown. Here, we delineate a hitherto uncharted cooperation between RTKs, RhoA GTPase, and p120 catenin in instructing a motile behavior to epithelial cells. We found that expression of an N-terminus–deleted p120 catenin in a variety of epithelial cell types, including primary keratinocytes, effectively competes for endogenous p120 at cadherin binding sites and abrogates EGF-stimulated cell motility as well as HGF-induced cell scattering. The deleted mutant also inhibits the PI3K-dependent RhoA activation ensuing receptor activation. Conversely, we also show that the ectopic expression of full-length p120 in epithelial cells promotes cytoskeletal changes, stimulates cell motility, and activates RhoA. Both motogenic response to p120 and RhoA activation require coactivation of signaling downstream of RTKs as they are suppressed by ablation of the Ras/PI3K pathway. These studies demonstrate that p120 catenin is a necessary target of RTKs in regulating cell motility and help define a novel pathway leading to RhoA activation, which may contribute to the early steps of metastatic invasion.
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Gares, Sheryl L., and Linda M. Pilarski. "Balancing Thymocyte Adhesion and Motility: A Functional Linkage Between β1 Lntegrins and The Motility Receptor RHAMM." Developmental Immunology 7, no. 2-4 (2000): 209–25. http://dx.doi.org/10.1155/2000/94616.
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Thymocyte differentiation involves several processes that occur in different anatomic sites within the thymus. Therefore, thymocytes must have the ability to respond to signals received from stromal cells and adopt either adhesive or motile behavior. We will discuss our data indicating human thymocytes use α4β1 integrin, α5β1 integrin and RHAMM to mediate these activities. Immature multinegative (MN; CD3–4–8–19-) thymocytes use α4β1 and α5β1 integrins to mediate weak and strong adhesion. This subset also uses α4β1 integrin to mediate motility. As thymocytes differentiate, they begin to express and use RHAMM to mediate motility in conjunction with α4β1 and α5β1 integrins. Motile thymocytes use β1 integrins to maintain weakly adhesive contacts with substrate to provide traction for locomoting cells, thus weak adhesion is a requirement of motile behavior. Hyaluronan (HA) is also required by thymocytes to mediate motility. HA binding to cell surface RHAMM redistributes intracellular RHAMM to the cell surface where it functions to mediate motility. We propose that the decision to maintain adhesive or motile behavior is based on the balance between low and high avidity binding conformations of β1 integrins on thymocytes and that RHAMM:HA interactions decrease high avidity binding conformations of integrins pushing the balance toward motile behavior.
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Soll, David R., Deborah Wessels, Spencer Kuhl, and Daniel F. Lusche. "How a Cell Crawls and the Role of Cortical Myosin II." Eukaryotic Cell 8, no. 9 (July 24, 2009): 1381–96. http://dx.doi.org/10.1128/ec.00121-09.
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ABSTRACT The movements of Dictyostelium discoideum amoebae translocating on a glass surface in the absence of chemoattractant have been reconstructed at 5-second intervals and motion analyzed by employing 3D-DIAS software. A morphometric analysis of pseudopods, the main cell body, and the uropod provides a comprehensive description of the basic motile behavior of a cell in four dimensions (4D), resulting in a list of 18 characteristics. A similar analysis of the myosin II phosphorylation mutant 3XASP reveals a role for the cortical localization of myosin II in the suppression of lateral pseudopods, formation of the uropod, cytoplasmic distribution of cytoplasm in the main cell body, and efficient motility. The results of the morphometric analysis suggest that pseudopods, the main cell body, and the uropod represent three motility compartments that are coordinated for efficient translocation. It provides a contextual framework for interpreting the effects of mutations, inhibitors, and chemoattractants on the basic motile behavior of D. discoideum. The generality of the characteristics of the basic motile behavior of D. discoideum must now be tested by similar 4D analyses of the motility of amoeboid cells of higher eukaryotic cells, in particular human polymorphonuclear leukocytes.
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Othy, Shivashankar, Amit Jairaman, Joseph L. Dynes, Tobias X. Dong, Cornelia Tune, Andriy V. Yeromin, Angel Zavala, et al. "Regulatory T cells suppress Th17 cell Ca2+signaling in the spinal cord during murine autoimmune neuroinflammation." Proceedings of the National Academy of Sciences 117, no. 33 (July 30, 2020): 20088–99. http://dx.doi.org/10.1073/pnas.2006895117.
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T lymphocyte motility and interaction dynamics with other immune cells are vital determinants of immune responses. Regulatory T (Treg) cells prevent autoimmune disorders by suppressing excessive lymphocyte activity, but how interstitial motility patterns of Treg cells limit neuroinflammation is not well understood. We used two-photon microscopy to elucidate the spatial organization, motility characteristics, and interactions of endogenous Treg and Th17 cells together with antigen-presenting cells (APCs) within the spinal cord leptomeninges in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Th17 cells arrive before the onset of clinical symptoms, distribute uniformly during the peak, and decline in numbers during later stages of EAE. In contrast, Treg cells arrive after Th17 cells and persist during the chronic phase. Th17 cells meander widely, interact with APCs, and exhibit cytosolic Ca2+transients and elevated basal Ca2+levels before the arrival of Treg cells. In contrast, Treg cells adopt a confined, repetitive-scanning motility while contacting APCs. These locally confined but highly motile Treg cells limit Th17 cells from accessing APCs and suppress Th17 cell Ca2+signaling by a mechanism that is upstream of store-operated Ca2+entry. Finally, Treg cell depletion increases APC numbers in the spinal cord and exaggerates ongoing neuroinflammation. Our results point to fundamental differences in motility characteristics between Th17 and Treg cells in the inflamed spinal cord and reveal three potential cellular mechanisms by which Treg cells regulate Th17 cell effector functions: reduction of APC density, limiting access of Th17 cells to APCs, and suppression of Th17 Ca2+signaling.
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Ratner, S., R. K. Jasti, and G. H. Heppner. "Motility of murine lymphocytes during transit through cell cycle. Analysis by a new in vitro assay." Journal of Immunology 140, no. 2 (January 15, 1988): 583–88. http://dx.doi.org/10.4049/jimmunol.140.2.583.
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Abstract The relationship between the basal (spontaneous) motility of murine lymphocytes and their position in the cell cycle was examined in a new collagen gel motility assay system. Concanavalin A-stimulated or control lymphocytes were allowed to locomote into slabs of type I collagen gel. The assay configuration permitted extraction of both total populations and locomotory subpopulations as viable, single-cell suspensions suitable for phenotypic and cell analysis. Concanavalin A stimulation resulted in a significant increase in the mean distance traveled by the leading cell front in 4 hr, from 23 microns (controls) to 67 microns. The estimated percentage of motile cells increased from 0.9 to 2.8%. Similar increases were observed after 18 hr of locomotion. The SIg+, Thy-1+, L3T4+, and Ly-2+ subsets exhibited equivalent increases in motility. Total populations and locomotory subpopulations were allowed to incorporate 5-bromo-2'-deoxyuridine, and their cell cycle profiles were compared by dual parameter anti-5-bromo-2'-deoxyuridine, propidium iodide fluorescence analysis. Total population and locomotory subpopulations did not differ significantly with respect to the ratio G0/G1:S, indicating that lymphocytes in these two phases exhibited approximately equal motility. Cells in late S and G2 + M were significantly less motile; locomotory subpopulations contained 60 to 75% fewer G2 + M cells than the total populations from which they were derived. Taken together, the results indicate that the concanavalin A-induced increase in motility commences before S phase and that motility diminishes shortly before or during G2 + M.
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Strandkvist, Charlotte, Jeppe Juul, Buzz Baum, Alexandre J. Kabla, and Tom Duke. "A kinetic mechanism for cell sorting based on local variations in cell motility." Interface Focus 4, no. 6 (December 6, 2014): 20140013. http://dx.doi.org/10.1098/rsfs.2014.0013.
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Our current understanding of cell sorting relies on physical difference, either in the interfacial properties or motile force, between cell types. But is such asymmetry a prerequisite for cell sorting? We test this using a minimal model in which the two cell populations are identical with respect to their physical properties and differences in motility arise solely from how cells interact with their surroundings. The model resembles the Schelling model used in social sciences to study segregation phenomena at the scale of societies. Our results demonstrate that segregation can emerge solely from cell motility being a dynamic property that changes in response to the local environment of the cell, but that additional mechanisms are necessary to reproduce the envelopment behaviour observed in vitro . The time course of segregation follows a power law, in agreement with the scaling reported from experiment and in other models of motility-driven segregation.
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Soulavie, Fabien, David Piepenbrock, Joëlle Thomas, Jennifer Vieillard, Jean-Luc Duteyrat, Elisabeth Cortier, Anne Laurençon, Martin C. Göpfert, and Bénédicte Durand. "hemingway is required for sperm flagella assembly and ciliary motility in Drosophila." Molecular Biology of the Cell 25, no. 8 (April 15, 2014): 1276–86. http://dx.doi.org/10.1091/mbc.e13-10-0616.
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Cilia play major functions in physiology and development, and ciliary dysfunctions are responsible for several diseases in humans called ciliopathies. Cilia motility is required for cell and fluid propulsion in organisms. In humans, cilia motility deficiencies lead to primary ciliary dyskinesia, with upper-airways recurrent infections, left–right asymmetry perturbations, and fertility defects. In Drosophila, we identified hemingway (hmw) as a novel component required for motile cilia function. hmw encodes a 604–amino acid protein characterized by a highly conserved coiled-coil domain also found in the human orthologue, KIAA1430. We show that HMW is conserved in species with motile cilia and that, in Drosophila, hmw is expressed in ciliated sensory neurons and spermatozoa. We created hmw-knockout flies and found that they are hearing impaired and male sterile. hmw is implicated in the motility of ciliated auditory sensory neurons and, in the testis, is required for elongation and maintenance of sperm flagella. Because HMW is absent from mature flagella, we propose that HMW is not a structural component of the motile axoneme but is required for proper acquisition of motile properties. This identifies HMW as a novel, evolutionarily conserved component necessary for motile cilium function and flagella assembly.
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Schafer, Dorothy A., Matthew D. Welch, Laura M. Machesky, Paul C. Bridgman, Shelley M. Meyer, and John A. Cooper. "Visualization and Molecular Analysis of Actin Assembly in Living Cells." Journal of Cell Biology 143, no. 7 (December 28, 1998): 1919–30. http://dx.doi.org/10.1083/jcb.143.7.1919.
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Actin filament assembly is critical for eukaryotic cell motility. Arp2/3 complex and capping protein (CP) regulate actin assembly in vitro. To understand how these proteins regulate the dynamics of actin filament assembly in a motile cell, we visualized their distribution in living fibroblasts using green flourescent protein (GFP) tagging. Both proteins were concentrated in motile regions at the cell periphery and at dynamic spots within the lamella. Actin assembly was required for the motility and dynamics of spots and for motility at the cell periphery. In permeabilized cells, rhodamine-actin assembled at the cell periphery and at spots, indicating that actin filament barbed ends were present at these locations. Inhibition of the Rho family GTPase rac1, and to a lesser extent cdc42 and RhoA, blocked motility at the cell periphery and the formation of spots. Increased expression of phosphatidylinositol 5-kinase promoted the movement of spots. Increased expression of LIM–kinase-1, which likely inactivates cofilin, decreased the frequency of moving spots and led to the formation of aggregates of GFP–CP. We conclude that spots, which appear as small projections on the surface by whole mount electron microscopy, represent sites of actin assembly where local and transient changes in the cortical actin cytoskeleton take place.
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Steinberg, Nitai, Alona Keren-Paz, Qihui Hou, Shany Doron, Keren Yanuka-Golub, Tsviya Olender, Rotem Hadar, et al. "The extracellular matrix protein TasA is a developmental cue that maintains a motile subpopulation within Bacillus subtilis biofilms." Science Signaling 13, no. 632 (May 19, 2020): eaaw8905. http://dx.doi.org/10.1126/scisignal.aaw8905.
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In nature, bacteria form biofilms—differentiated multicellular communities attached to surfaces. Within these generally sessile biofilms, a subset of cells continues to express motility genes. We found that this subpopulation enabled Bacillus subtilis biofilms to expand on high-friction surfaces. The extracellular matrix (ECM) protein TasA was required for the expression of flagellar genes. In addition to its structural role as an adhesive fiber for cell attachment, TasA acted as a developmental signal stimulating a subset of biofilm cells to revert to a motile phenotype. Transcriptomic analysis revealed that TasA stimulated the expression of a specific subset of genes whose products promote motility and repress ECM production. Spontaneous suppressor mutations that restored motility in the absence of TasA revealed that activation of the biofilm-motility switch by the two-component system CssR/CssS antagonized the TasA-mediated reversion to motility in biofilm cells. Our results suggest that although mostly sessile, biofilms retain a degree of motility by actively maintaining a motile subpopulation.
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Schwarzer, Sabine, Marta Rodriguez-Franco, Hanna M. Oksanen, and Tessa E. F. Quax. "Growth Phase Dependent Cell Shape of Haloarcula." Microorganisms 9, no. 2 (January 22, 2021): 231. http://dx.doi.org/10.3390/microorganisms9020231.
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Several haloarchaea are reported to be pleomorphic, while others exhibit remarkable shapes, such as squares. Recently, Haloferax volcanii was found to alter its morphology during growth. Cells are motile rods in early exponential phase, and immotile plates in stationary phase. It is unknown if this growth phase dependent cell shape alteration is a specific feature of Hfx. volcanii, or conserved amongst haloarchaea. Here, we studied the cell shape and motility of two haloarchaea species Haloarcula hispanica and Haloarcula californiae. With a combination of light and electron microscopy, we observed that both strains undergo a growth phase dependent morphological development, albeit in a slightly different fashion as Hfx. volcanii. For both Haloarcula strains, the cell size is changing throughout growth. Cell shape seems to be related with motility, as highly motile cells on semi-solid agar plates are predominantly rod-shaped. We conclude that the growth phase dependent cell morphology alteration might be a common feature amongst haloarchaea, and that cell shape is generally linked with a motile life style. The conservation of this phenomenon underscores the importance of studies of the molecular mechanisms regulating cell shape in archaea.
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Liu, Runfeng, Xingchen Huang, Qinqiang Sun, Zhen Hou, Weihan Yang, Junjun Zhang, Pengfei Zhang, Liangfeng Huang, Yangqing Lu, and Qiang Fu. "Comparative Proteomic Analyses of Poorly Motile Swamp Buffalo Spermatozoa Reveal Low Energy Metabolism and Deficiencies in Motility-Related Proteins." Animals 12, no. 13 (July 1, 2022): 1706. http://dx.doi.org/10.3390/ani12131706.
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The acquisition of mammalian sperm motility is a main indicator of epididymal sperm maturation and helps ensure fertilization. Poor sperm motility will prevent sperm cells from reaching the fertilization site, resulting in fertilization failure. To investigate the proteomic profiling of normal and poorly motile buffalo spermatozoa, a strategy applying liquid chromatography tandem mass spectrometry combined with tandem mass targeting was used. As a result, 145 differentially expressed proteins (DEPs) were identified in poorly motile spermatozoa (fold change > 1.5), including 52 upregulated and 93 downregulated proteins. The upregulated DEPs were mainly involved in morphogenesis and regulation of cell differentiation. The downregulated DEPs were involved with transport, oxidation-reduction, sperm motility, regulation of cAMP metabolism and regulation of DNA methylation. The mRNA and protein levels of PRM1 and AKAP3 were lower in poorly motile spermatozoa, while the expressions of SDC2, TEKT3 and IDH1 were not correlated with motility, indicating that their protein changes were affected by transcription or translation. Such changes in the expression of these proteins suggest that the formation of poorly motile buffalo spermatozoa reflects a low efficiency of energy metabolism, decreases in sperm protamine proteins, deficiencies in motility-related proteins, and variations in tail structural proteins. Such proteins could be biomarkers of poorly motile spermatozoa. These results illustrate some of the molecular mechanisms associated with poorly motile spermatozoa and provide clues for finding molecular markers of these pathways.
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Herbert, Shane P., and Guilherme Costa. "Sending messages in moving cells: mRNA localization and the regulation of cell migration." Essays in Biochemistry 63, no. 5 (July 19, 2019): 595–606. http://dx.doi.org/10.1042/ebc20190009.
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Abstract Cell migration is a fundamental biological process involved in tissue formation and homeostasis. The correct polarization of motile cells is critical to ensure directed movement, and is orchestrated by many intrinsic and extrinsic factors. Of these, the subcellular distribution of mRNAs and the consequent spatial control of translation are key modulators of cell polarity. mRNA transport is dependent on cis-regulatory elements within transcripts, which are recognized by trans-acting proteins that ensure the efficient delivery of certain messages to the leading edge of migrating cells. At their destination, translation of localized mRNAs then participates in regional cellular responses underlying cell motility. In this review, we summarize the key findings that established mRNA targetting as a critical driver of cell migration and how the characterization of polarized mRNAs in motile cells has been expanded from just a few species to hundreds of transcripts. We also describe the molecular control of mRNA trafficking, subsequent mechanisms of local protein synthesis and how these ultimately regulate cell polarity during migration.
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Hauzenberger, D., J. Klominek, J. Holgersson, S. E. Bergström, and K. G. Sundqvist. "Triggering of motile behavior in T lymphocytes via cross-linking of alpha 4 beta 1 and alpha L beta 2." Journal of Immunology 158, no. 1 (January 1, 1997): 76–84. http://dx.doi.org/10.4049/jimmunol.158.1.76.
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Abstract The mechanisms by which T lymphocytes are transformed from passively transported cells during circulation in the vascular system to actively migrating cells during extravasation are unknown. Therefore, the possibility that lymphocyte receptors are capable of inducing motility was investigated using a modified Boyden chamber assay. Cross-linking of alphaL beta2 and alpha4 beta1 on human T lymphocytes (T cell line and peripheral blood T cells) with immobilized mAbs induced motile behavior on fibronectin, laminin, collagen type IV, and poly-L-lysine. This induction of T cell migration was very potent and in most cases more efficient than pretreatment of the cells with phorbol esters. In contrast, control Abs to several other integrin- and non-integrin molecules present on T lymphocytes did not induce T cell migration. Anti-CD3 Abs themselves did not trigger motile behavior. However, anti-CD3 promoted T cell migration in the Boyden chamber system if present simultaneously with 40-kDa alpha4 beta1 binding fibronectin fragments or alphaL beta2 binding intercellular adhesion molecule-1/hIgG1Fc fusion proteins on the upper side of the filter. Abs to other surface components on T cells did not trigger motility when presented together with the 40-kDa fibronectin fragments or the intercellular adhesion molecule-1/hIgG1Fc fusion proteins. The induction of motile behavior could be blocked if the T cells were pretreated with Genistein and Calphostin C, indicating the involvement of a protein tyrosine kinase and protein kinase C-dependent signaling pathway in triggering of T cell motility via integrins. These results indicate that alphaL beta2 and alpha4 beta1 on T lymphocytes can selectively trigger motile behavior when cross-linked by their endothelial or extracellular matrix ligands. Furthermore, these data indicate that cross-linking of CD3 facilitates ligand binding and subsequent triggering of a motile phenotype by alphaL beta2 and alpha4 beta1.
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Ormonde, Patricia, Per Hörstedt, Ronan O'Toole, and Debra L. Milton. "Role of Motility in Adherence to and Invasion of a Fish Cell Line by Vibrio anguillarum." Journal of Bacteriology 182, no. 8 (April 15, 2000): 2326–28. http://dx.doi.org/10.1128/jb.182.8.2326-2328.2000.
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ABSTRACT To understand further the role of the flagellum of Vibrio anguillarum in virulence, invasive and adhesive properties of isogenic motility mutants were analyzed by using a chinook salmon embryo cell line. Adhesion was unaffected but invasion of the cell line was significantly decreased in nonmotile or partially motile mutants, and the chemotactic mutant was hyperinvasive. These results suggest that active motility aids invasion by V. anguillarum, both in vivo and in vitro.
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Lee, Sieun, and Young-Ho Ahn. "Abstract 3861: Microscope-based sorting of highly motile cancer-associated fibroblasts using a photoconvertible fluorescent protein." Cancer Research 82, no. 12_Supplement (June 15, 2022): 3861. http://dx.doi.org/10.1158/1538-7445.am2022-3861.
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Abstract In the tumor microenvironment, cancer-associated fibroblasts (CAFs) are known to play key roles in promoting cancer cell invasion and cancer progression. CAFs are also highly invasive compared with normal fibroblasts in a 3-D co-culture system with lung cancer cells. Due to CAF heterogeneity, there are various differences in cell motility even within a CAF population. To classify CAFs according to their motility, we named less motile CAFs as “static CAFs” and more motile CAFs as “motile CAFs”. To separate and isolate these static CAFs and motile CAFs from a 3-D co-culture system, CAFs were transfected with a green-to-red photoconvertible fluorescent protein, Dendra2. Dendra2-transfected CAFs at specific areas (i.e., static or motile CAFs) were UV-irradiated using a confocal microscope. CAFs with red fluorescence were then isolated by flow cytometry and were subjected to RNA sequencing. In gene ontology and gene set enrichment analyses, two types of CAFs showed significant differences in global gene expression patterns. These data suggest that heterogeneous CAFs with different motility have distinct roles in the regulation of various signaling pathways in the tumor microenvironment. Citation Format: Sieun Lee, Young-Ho Ahn. Microscope-based sorting of highly motile cancer-associated fibroblasts using a photoconvertible fluorescent protein [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3861.
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Varnum, B., K. B. Edwards, and D. R. Soll. "Dictyostelium amebae alter motility differently in response to increasing versus decreasing temporal gradients of cAMP." Journal of Cell Biology 101, no. 1 (July 1, 1985): 1–5. http://dx.doi.org/10.1083/jcb.101.1.1.
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Using a perfusion chamber, we examined the behavior of individual amebae in increasing and decreasing temporal gradients of cAMP. We demonstrated that amebae respond to increasing temporal gradients of cAMP with stimulated motility and to corresponding decreasing temporal gradients with depressed motility. Depressed motility observed in decreasing temporal gradients corresponded to the inhibited levels observed when cAMP was applied at constant concentrations. These results were consistent with a simple model for the motile behavior of amebae in an early aggregation territory in which nondissipating waves of cAMP originate at the aggregation center and travel outward periodically. We conclude that chemotactically responsive amebae can assess whether a temporal gradient of chemoattractant is increasing or decreasing in the absence of a spatial gradient, and can adjust their motility accordingly.
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Madeja, Zbigniew, Iwona Szymkiewicz, Anna Żaczek, Jolanta Sroka, Katarzyna Miękus, and Włodzimierz Korohoda. "Contact-activated migration of melanoma B16 and sarcoma XC cells." Biochemistry and Cell Biology 79, no. 4 (August 1, 2001): 425–40. http://dx.doi.org/10.1139/o01-029.
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During migration, tumour cells interact with neighbouring neoplastic and normal host cells, and such interaction may influence their motile activity. We investigated the effect of homotypic collisions on the motile activity of two tumour cell lines, mouse melanoma B16 and rat sarcoma XC, and nontransformed human skin fibroblasts. It was found that the tumour cells show only limited motile activity when moving as single cells without contact with neighbours. At a higher density of the culture (and also at a greater number of cell to cell contacts) the activation of motility of investigated tumour cells was observed. On the other hand, the normal human skin fibroblasts showed a typical reaction of density-dependent inhibition of motility. The motile activity of tumour cells was not affected by conditioned media and was visibly dependent on a direct physical contact among colliding cells. The activation of cell movement was observed about 4050 min after the initial contact between tumour cells. Contact-activated migration of neoplastic cells was inhibited by 50 µM verapamil (a selective voltage-gated calcium channel inhibitor) and 10 µM gadolinium chloride (a nonspecific blocker of mechanosensitive ion channels) but not by pertussis toxin. The observation that homotypic collisions among tumour cells strongly increase their motile activity suggests that contact-activated migration may play a significant role in tumour invasion and metastasis.Key words: cell movement, metastases, contact activation of cell migration, contact inhibition.
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Prado, Mariana Brandão, Maria Isabel Melo Escobar, Rodrigo Nunes Alves, Bárbara Paranhos Coelho, Camila Felix de Lima Fernandes, Jacqueline Marcia Boccacino, Rebeca Piatniczka Iglesia, and Marilene Hohmuth Lopes. "Prion Protein at the Leading Edge: Its Role in Cell Motility." International Journal of Molecular Sciences 21, no. 18 (September 12, 2020): 6677. http://dx.doi.org/10.3390/ijms21186677.
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Cell motility is a central process involved in fundamental biological phenomena during embryonic development, wound healing, immune surveillance, and cancer spreading. Cell movement is complex and dynamic and requires the coordinated activity of cytoskeletal, membrane, adhesion and extracellular proteins. Cellular prion protein (PrPC) has been implicated in distinct aspects of cell motility, including axonal growth, transendothelial migration, epithelial–mesenchymal transition, formation of lamellipodia, and tumor migration and invasion. The preferential location of PrPC on cell membrane favors its function as a pivotal molecule in cell motile phenotype, being able to serve as a scaffold protein for extracellular matrix proteins, cell surface receptors, and cytoskeletal multiprotein complexes to modulate their activities in cellular movement. Evidence points to PrPC mediating interactions of multiple key elements of cell motility at the intra- and extracellular levels, such as integrins and matrix proteins, also regulating cell adhesion molecule stability and cell adhesion cytoskeleton dynamics. Understanding the molecular mechanisms that govern cell motility is critical for tissue homeostasis, since uncontrolled cell movement results in pathological conditions such as developmental diseases and tumor dissemination. In this review, we discuss the relevant contribution of PrPC in several aspects of cell motility, unveiling new insights into both PrPC function and mechanism in a multifaceted manner either in physiological or pathological contexts.
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Williams, Michelle, Michelle D. Hoffman, Jeremy J. Daniel, Seth M. Madren, Andi Dhroso, Dmitry Korkin, Scott A. Givan, Stephen C. Jacobson, and Pamela J. B. Brown. "Short-Stalked Prosthecomicrobium hirschii Cells Have a Caulobacter-Like Cell Cycle." Journal of Bacteriology 198, no. 7 (February 1, 2016): 1149–59. http://dx.doi.org/10.1128/jb.00896-15.
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ABSTRACTThe dimorphic alphaproteobacteriumProsthecomicrobium hirschiihas both short-stalked and long-stalked morphotypes. Notably, these morphologies do not arise from transitions in a cell cycle. Instead, the maternal cell morphology is typically reproduced in daughter cells, which results in microcolonies of a single cell type. In this work, we further characterized the short-stalked cells and found that these cells have aCaulobacter-like life cycle in which cell division leads to the generation of two morphologically distinct daughter cells. Using a microfluidic device and total internal reflection fluorescence (TIRF) microscopy, we observed that motile short-stalked cells attach to a surface by means of a polar adhesin. Cells attached at their poles elongate and ultimately release motile daughter cells. Robust biofilm growth occurs in the microfluidic device, enabling the collection of synchronous motile cells and downstream analysis of cell growth and attachment. Analysis of a draftP. hirschiigenome sequence indicates the presence of CtrA-dependent cell cycle regulation. This characterization ofP. hirschiiwill enable future studies on the mechanisms underlying complex morphologies and polymorphic cell cycles.IMPORTANCEBacterial cell shape plays a critical role in regulating important behaviors, such as attachment to surfaces, motility, predation, and cellular differentiation; however, most studies on these behaviors focus on bacteria with relatively simple morphologies, such as rods and spheres. Notably, complex morphologies abound throughout the bacteria, with striking examples, such asP. hirschii, found within the stalkedAlphaproteobacteria.P. hirschiiis an outstanding candidate for studies of complex morphology generation and polymorphic cell cycles. Here, the cell cycle and genome ofP. hirschiiare characterized. This work sets the stage for future studies of the impact of complex cell shapes on bacterial behaviors.
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Uatay, Aydar. "A Stochastic Modelling Framework for Single Cell Migration: Coupling Contractility and Focal Adhesions." Symmetry 12, no. 8 (August 12, 2020): 1348. http://dx.doi.org/10.3390/sym12081348.
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The interaction of the actin cytoskeleton with cell–substrate adhesions is necessary for cell migration. While the trajectories of motile cells have a stochastic character, investigations of cell motility mechanisms rarely elaborate on the origins of the observed randomness. Here, guided by a few fundamental attributes of cell motility, I construct a minimal stochastic cell migration model from ground-up. The resulting model couples a deterministic actomyosin contractility mechanism with stochastic cell–substrate adhesion kinetics, and yields a well-defined piecewise deterministic process. Numerical simulations reproduce several experimentally observed results, including anomalous diffusion, tactic migration and contact guidance. This work provides a basis for the development of cell–cell collision and population migration models.
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Melkonian, M. "Centrin-Mediated Motility: A Novel Cell Motility Mechanism in Eukaryotic Cells." Botanica Acta 102, no. 1 (February 1989): 3–4. http://dx.doi.org/10.1111/j.1438-8677.1989.tb00059.x.
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Fletcher, Sarah J., and Joshua Z. Rappoport. "The role of vesicle trafficking in epithelial cell motility." Biochemical Society Transactions 37, no. 5 (September 21, 2009): 1072–76. http://dx.doi.org/10.1042/bst0371072.
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Cell motility is important for many physiological and pathological processes including organ development, wound healing, cancer metastasis and correct immune responses. In particular, epithelial wound healing is both a medically relevant topic and a common experimental model. Mechanisms underlying generation of a polarized cell and maintenance of a motile phenotype during steady-state migration are not well understood. Polarized trafficking of bulk membrane and cell adhesion molecules has been implicated in regulation of cell motility. The present review focuses on the role of different trafficking pathways in epithelial cell migration, including clathrin-mediated endocytosis, caveolar endocytosis, exocytosis of biosynthetic cargo, ‘short-loop’ and ‘long-loop’ endosomal recycling.
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Döbereiner, Hans-Günther, Benjamin J. Dubin-Thaler, Gregory Giannone, and Michael P. Sheetz. "Force sensing and generation in cell phases: analyses of complex functions." Journal of Applied Physiology 98, no. 4 (April 2005): 1542–46. http://dx.doi.org/10.1152/japplphysiol.01181.2004.
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Cellular morphology is determined by motility, force sensing, and force generation that must be finely controlled in a dynamic fashion. Contractile and extensile functions are integrated with the overall cytoskeleton, including linkages from the cytoplasmic cytoskeleton to the extracellular matrix and other cells by force sensing. During development, as cells differentiate, variations in protein expression levels result in morphological changes. There are two major explanations for motile behavior: either cellular motility depends in a continuous fashion on cell composition or it exhibits phases wherein only a few protein modules are activated locally for a given time. Indeed, in support of the latter model, the quantification of cell spreading and other motile activities shows multiple distinct modes of behavior, which we term “phases” because there exist abrupt transitions between them. Cells in suspension have a basal level of motility that enables them to probe their immediate environment. After contacting a matrix-coated surface, they rapidly transition to an activated spreading phase. After the development of a significant contact area, the cells contract repeatedly to determine the rigidity of the substrate and then develop force on matrix contacts. When cells are fully spread, extension activity is significantly decreased and focal complexes start to assemble near the cell periphery. For each of these phases, there are significant differences in protein activities, which correspond to differences in function. Thus overall morphological change of a tissue is driven by chemical signals and force-dependent activation of one or more motile phases in limited cell regions for defined periods.
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Agustí, Gemma, Oihane Astola, Elisabeth Rodríguez-Güell, Esther Julián, and Marina Luquin. "Surface Spreading Motility Shown by a Group of Phylogenetically Related, Rapidly Growing Pigmented Mycobacteria Suggests that Motility Is a Common Property of Mycobacterial Species but Is Restricted to Smooth Colonies." Journal of Bacteriology 190, no. 20 (August 8, 2008): 6894–902. http://dx.doi.org/10.1128/jb.00572-08.
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ABSTRACT Motility in mycobacteria was described for the first time in 1999. It was reported that Mycobacterium smegmatis and Mycobacterium avium could spread on the surface of solid growth medium by a sliding mechanism and that the presence of cell wall glycopeptidolipids was essential for motility. We recently reported that Mycobacterium vaccae can also spread on growth medium surfaces; however, only smooth colonies presented this property. Smooth colonies of M. vaccae do not produce glycopeptidolipids but contain a saturated polyester that is absent in rough colonies. Here, we demonstrate that Mycobacterium chubuense, Mycobacterium gilvum, Mycobacterium obuense, and Mycobacterium parafortuitum, which are phylogenetically related to M. vaccae, are also motile. Such motility is restricted to smooth colonies, since natural rough mutants are nonmotile. Thin-layer chromatography analysis of the content of cell wall lipids confirmed the absence of glycopeptidolipids. However, compounds like the above-mentioned M. vaccae polyester were detected in all the strains but only in smooth colonies. Scanning electron microscopy showed great differences in the arrangement of the cells between smooth and rough colonies. The data obtained suggest that motility is a common property of environmental mycobacteria, and this capacity correlates with the smooth colonial morphotype. The species studied in this work do not contain glycopeptidolipids, so cell wall compounds or extracellular materials other than glycopeptidolipids are implicated in mycobacterial motility. Furthermore, both smooth motile and rough nonmotile variants formed biofilms on glass and polystyrene surfaces.
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O'Neil, Heather S., and Hélène Marquis. "Listeria monocytogenes Flagella Are Used for Motility, Not as Adhesins, To Increase Host Cell Invasion." Infection and Immunity 74, no. 12 (September 18, 2006): 6675–81. http://dx.doi.org/10.1128/iai.00886-06.
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ABSTRACT Flagellar structures contribute to the virulence of multiple gastrointestinal pathogens either as the effectors of motility, as adhesins, or as a secretion apparatus for virulence factors. Listeria monocytogenes is a food-borne, gram-positive pathogen that uses flagella to increase the efficiency of epithelial cell invasion (A. Bigot, H. Pagniez, E. Botton, C. Frehel, I. Dubail, C. Jacquet, A. Charbit, and C. Raynaud, Infect. Immun. 73:5530-5539, 2005; L. Dons, E. Eriksson, Y. Jin, M. E. Rottenberg, K. Kristensson, C. N. Larsen, J. Bresciani, and J. E. Olsen, Infect. Immun. 72:3237-3244, 2004). In this study, we aimed to elucidate the mechanism by which flagella contribute to L. monocytogenes invasion. To examine the role of flagella as adhesins, invasion and adhesion assays were performed with flagellated motile and nonmotile bacteria and nonflagellated bacteria. We observed that flagellated but nonmotile bacteria do not adhere to or invade human epithelial cells more efficiently than nonflagellated bacteria. These results indicated that flagella do not function as adhesins to enhance the adhesion of L. monocytogenes to targeted host cells. Instead, it appears that motility is important for tissue culture invasion. Furthermore, we tested whether motility contributes to early colonization of the gastrointestinal tract using a competitive index assay in which mice were infected orally with motile and nonmotile bacteria in a 1:1 ratio. Differential bacterial counts demonstrated that motile bacteria outcompete nonmotile bacteria in the colonization of the intestines at early time points postinfection. This difference is also reflected in invasion of the liver 12 h later, suggesting that flagellum-mediated motility enhances L. monocytogenes infectivity soon after bacterial ingestion in vivo.
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Takayama, Airi, Masayuki Sato, Thumkeo Dean, Toshio Yanagida, and Masahiro Ueda. "2P235 Roles of PI3 kinase in electrotacitc response of Dictyostelium cells(39. Cell motility,Poster Session,Abstract,Meeting Program of EABS & BSJ 2006)." Seibutsu Butsuri 46, supplement2 (2006): S354. http://dx.doi.org/10.2142/biophys.46.s354_3.
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Higashi, Dustin L., Shaun W. Lee, Aurelie Snyder, Nathan J. Weyand, Antony Bakke, and Magdalene So. "Dynamics of Neisseria gonorrhoeae Attachment: Microcolony Development, Cortical Plaque Formation, and Cytoprotection." Infection and Immunity 75, no. 10 (August 6, 2007): 4743–53. http://dx.doi.org/10.1128/iai.00687-07.
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ABSTRACT Neisseria gonorrhoeae is the bacterium that causes gonorrhea, a major sexually transmitted disease and a significant cofactor for human immunodeficiency virus transmission. The retactile N. gonorrhoeae type IV pilus (Tfp) mediates twitching motility and attachment. Using live-cell microscopy, we reveal for the first time the dynamics of twitching motility by N. gonorrhoeae in its natural environment, human epithelial cells. Bacteria aggregate into microcolonies on the cell surface and induce a massive remodeling of the microvillus architecture. Surprisingly, the microcolonies are motile, and they fuse to form progressively larger structures that undergo rapid reorganization, suggesting that bacteria communicate with each other during infection. As reported, actin plaques form beneath microcolonies. Here, we show that cortical plaques comigrate with motile microcolonies. These activities are dependent on pilT, the Tfp retraction locus. Cultures infected with a pilT mutant have significantly higher numbers of apoptotic cells than cultures infected with the wild-type strain. Inducing pilT expression with isopropyl-β-d-thiogalactopyranoside partially rescues cells from infection-induced apoptosis, demonstrating that Tfp retraction is intrinsically cytoprotective for the host. Tfp-mediated attachment is therefore a continuum of microcolony motility and force stimulation of host cell signaling, leading to a cytoprotective effect.
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Basson, Marc D., Matthew A. Sanders, Ruben Gomez, James Hatfield, Richard VanderHeide, Vijayalakshmi Thamilselvan, Jianhu Zhang, and Mary F. Walsh. "Focal adhesion kinase protein levels in gut epithelial motility." American Journal of Physiology-Gastrointestinal and Liver Physiology 291, no. 3 (September 2006): G491—G499. http://dx.doi.org/10.1152/ajpgi.00292.2005.
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Mucosal healing requires migration and proliferation. Most studies of focal adhesion kinase (FAK), a protein that regulates motility, proliferation, and apoptosis, have focused on rapid phosphorylation. We reported lower FAK protein levels in motile Caco-2 colon cancer cells and postulated that this reduction in FAK available for activation might impact cell migration and mucosal healing. Therefore, total and active FAK (FAK397) immunoreactivity was assessed at the migrating fronts of human Caco-2 and rat IEC-6 intestinal epithelial cells. Caco-2 and IEC-6 motility, quantitated as migration into linear or circular wounds, was examined following FAK protein inhibition by small interfering RNA (siRNA). FAK protein stability and mRNA expression were ascertained by cycloheximide decay, RT-PCR, and in situ hybridization in static and migrating Caco-2 cells. Cells at the migrating front of Caco-2 and IEC-6 monolayers exhibited lower immunostaining for both total and activated FAK than cells immediately behind the front. Western blot analysis also demonstrated diminished FAK protein levels in motile cells by ≥30% in both the differential density seeding and multiple scrape models. siRNA FAK protein inhibition enhanced motility in both the linear scrape (20% in Caco-2) and circular wound (16% in Caco-2 and 19% in IEC-6 cells) models. FAK protein degradation did not differ in motile and static Caco-2 cells and was unaffected by FAK397 phosphorylation, but FAK mRNA was lower in migrating Caco-2 cells. Thus FAK protein abundance appears regulated at the mRNA level during gut epithelial cell motility and may influence epithelial cell migration coordinately with signals that modify FAK phosphorylation.
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Barwe, Sonali P., Gopalakrishnapillai Anilkumar, Sun Y. Moon, Yi Zheng, Julian P. Whitelegge, Sigrid A. Rajasekaran, and Ayyappan K. Rajasekaran. "Novel Role for Na,K-ATPase in Phosphatidylinositol 3-Kinase Signaling and Suppression of Cell Motility." Molecular Biology of the Cell 16, no. 3 (March 2005): 1082–94. http://dx.doi.org/10.1091/mbc.e04-05-0427.
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The Na,K-ATPase, consisting of α- and β-subunits, regulates intracellular ion homeostasis. Recent studies have demonstrated that Na,K-ATPase also regulates epithelial cell tight junction structure and functions. Consistent with an important role in the regulation of epithelial cell structure, both Na,K-ATPase enzyme activity and subunit levels are altered in carcinoma. Previously, we have shown that repletion of Na,K-ATPase β1-subunit (Na,K-β) in highly motile Moloney sarcoma virus-transformed Madin-Darby canine kidney (MSV-MDCK) cells suppressed their motility. However, until now, the mechanism by which Na,K-β reduces cell motility remained elusive. Here, we demonstrate that Na,K-β localizes to lamellipodia and suppresses cell motility by a novel signaling mechanism involving a cross-talk between Na,K-ATPase α1-subunit (Na,K-α) and Na,K-β with proteins involved in phosphatidylinositol 3-kinase (PI3-kinase) signaling pathway. We show that Na,K-α associates with the regulatory subunit of PI3-kinase and Na,K-β binds to annexin II. These molecular interactions locally activate PI3-kinase at the lamellipodia and suppress cell motility in MSV-MDCK cells, independent of Na,K-ATPase ion transport activity. Thus, these results demonstrate a new role for Na,K-ATPase in regulating carcinoma cell motility.
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Pearson, Gray W., and Tony Hunter. "Real-time imaging reveals that noninvasive mammary epithelial acini can contain motile cells." Journal of Cell Biology 179, no. 7 (December 31, 2007): 1555–67. http://dx.doi.org/10.1083/jcb.200706099.
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To determine how extracellular signal–regulated kinases (ERK) 1/2 promote mammary tumorigenesis, we examined the real-time behavior of cells in an organotypic culture of the mammary glandular epithelium. Inducible activation of ERK1/2 in mature acini elicits cell motility and disrupts epithelial architecture in a manner that is reminiscent of ductal carcinoma in situ; however, motile cells do not invade through the basement membrane and branching morphogenesis does not take place. ERK1/2-induced motility causes cells to move both within the cell monolayer that contacts the basement membrane surrounding the acinus and through the luminal space of the acinus. E-cadherin expression is reduced after ERK1/2 activation, but motility does not involve an epithelial–mesenchymal transition. Cell motility and the disruption of epithelial architecture require a Rho kinase– and myosin light chain kinase–dependent increase in the phosphorylation of myosin light chain 2. Our results identify a new mechanism for the disruption of architecture in epithelial acini and suggest that ERK1/2 can promote noninvasive motility in preinvasive mammary tumors.
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Takai, H., and M. Morisawa. "Change in intracellular K+ concentration caused by external osmolality change regulates sperm motility of marine and freshwater teleosts." Journal of Cell Science 108, no. 3 (March 1, 1995): 1175–81. http://dx.doi.org/10.1242/jcs.108.3.1175.
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We previously demonstrated that osmolality isotonic to the seminal plasma suppresses sperm motility in marine and freshwater teleosts, and exposure of sperm to hypertonicity of sea water or hypotonicity of fresh water, respectively, induces the initiation of sperm motility at spawning. The motile sperm became immotile by return of osmolality to the isotonic osmolality both in a marine teleost, the puffer fish, and a freshwater teleost, the zebrafish. The initiation and termination of sperm motility could be repeated several times by changing surrounding osmolality in both species. In demembranated sperm, motility was suppressed by a K+ concentration equivalent to the seminal salt concentration in both puffer and zebrafish. Demembranated puffer sperm were reactivated when K+ concentration of the reactivating solution increased. Conversely, initiation of motility in the demembranated zebrafish sperm was induced by decreasing K+ concentration. The initiation and termination of the demembranated sperm were alternately repeated by changing K+ concentration of the reactivation solution in both species. Furthermore, intracellular K+ concentration rose when sperm motility of the puffer was initiated in hypertonic solutions. These results suggest that change in external osmolality is converted into change in intracellular K+ concentration, and that the change affects the flagellar axoneme as a signal to initiate or terminate sperm motility. The initiation and termination of motility in the demembranated puffer sperm were caused at a high pH and a low pH of the reactivating solution, respectively, suggesting the contribution of intracellular pH in the regulation of flagellar motility.
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Chen, Rui, Sarah B. Guttenplan, Kris M. Blair, and Daniel B. Kearns. "Role of the σD-Dependent Autolysins in Bacillus subtilis Population Heterogeneity." Journal of Bacteriology 191, no. 18 (June 19, 2008): 5775–84. http://dx.doi.org/10.1128/jb.00521-09.
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ABSTRACT Exponentially growing populations of Bacillus subtilis contain two morphologically and functionally distinct cell types: motile individuals and nonmotile multicellular chains. Motility differentiation arises because RNA polymerase and the alternative sigma factor σD activate expression of flagellin in a subpopulation of cells. Here we demonstrate that the peptidoglycan-remodeling autolysins under σD control, LytC, LytD, and LytF, are expressed in the same subpopulation of cells that complete flagellar synthesis. Morphological heterogeneity is explained by the expression of LytF that is necessary and sufficient for cell separation. Moreover, LytC is required for motility but not at the level of cell separation or flagellum biosynthesis. Rather, LytC appears to be important for flagellar function, and motility was restored to a LytC mutant by mutation of either lonA, encoding the LonA protease, or a gene encoding a previously unannotated swarming motility inhibitor, SmiA. We conclude that heterogeneous activation of σD-dependent gene expression is sufficient to explain both the morphological heterogeneity and functional heterogeneity present in vegetative B. subtilis populations.
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Kajiya, Hiroshi, Fujio Okamoto, Hidefumi Fukushima, Keisuke Takada, and Koji Okabe. "Mechanism and role of high-potassium-induced reduction of intracellular Ca2+ concentration in rat osteoclasts." American Journal of Physiology-Cell Physiology 285, no. 2 (August 2003): C457—C466. http://dx.doi.org/10.1152/ajpcell.00033.2003.
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Osteoclasts are multinucleated, bone-resorbing cells that show structural and functional differences between the resorbing and nonresorbing (motile) states during the bone resorption cycle. In the present study, we measured intracellular Ca2+ concentration ([Ca2+]i) in nonresorbing vs. resorbing rat osteoclasts. Basal [Ca2+]i in osteoclasts possessing pseudopodia (nonresorbing/motile state) was around 110 nM and significantly higher than that in actin ring-forming osteoclasts (resorbing state, around 50 nM). In nonresorbing/motile osteoclasts, exposure to high K+ reduced [Ca2+]i, whereas high K+ increased [Ca2+]i in resorbing state osteoclasts. In nonresorbing/motile cells, membrane depolarization and hyperpolarization applied by the patch-clamp technique decreased and increased [Ca2+]i, respectively. Removal of extracellular Ca2+ or application of 300 μM La3+ reduced [Ca2+]i to ∼50 nM in nonresorbing/motile osteoclasts, and high-K+-induced reduction of [Ca2+]i could not be observed under these conditions. Neither inhibition of intracellular Ca2+ stores or plasma membrane Ca2+ pumps nor blocking of L- and N-type Ca2+ channels significantly reduced [Ca2+]i. Exposure to high K+ inhibited the motility of nonresorbing osteoclasts and reduced the number of actin rings and pit formation in resorbing osteoclasts. These results indicate that in nonresorbing/motile osteoclasts, a La3+-sensitive Ca2+ entry pathway is continuously active under resting conditions, keeping [Ca2+]i high. Changes in membrane potential regulate osteoclastic motility by controlling the net amount of Ca2+ entry in a “reversed” voltage-dependent manner, i.e., depolarization decreases and hyperpolarization increases [Ca2+]i.
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TAYLOR, E. W. "Cell Motility." Journal of Cell Science 1986, Supplement 4 (January 1, 1986): 89–102. http://dx.doi.org/10.1242/jcs.1986.supplement_4.6.
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Gaskins, Elizabeth, Stacey Gilk, Nicolette DeVore, Tara Mann, Gary Ward, and Con Beckers. "Identification of the membrane receptor of a class XIV myosin in Toxoplasma gondii." Journal of Cell Biology 165, no. 3 (May 3, 2004): 383–93. http://dx.doi.org/10.1083/jcb.200311137.
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Apicomplexan parasites exhibit a unique form of substrate-dependent motility, gliding motility, which is essential during their invasion of host cells and during their spread between host cells. This process is dependent on actin filaments and myosin that are both located between the plasma membrane and two underlying membranes of the inner membrane complex. We have identified a protein complex in the apicomplexan parasite Toxoplasma gondii that contains the class XIV myosin required for gliding motility, TgMyoA, its associated light chain, TgMLC1, and two novel proteins, TgGAP45 and TgGAP50. We have localized this complex to the inner membrane complex of Toxoplasma, where it is anchored in the membrane by TgGAP50, an integral membrane glycoprotein. Assembly of the protein complex is spatially controlled and occurs in two stages. These results provide the first molecular description of an integral membrane protein as a specific receptor for a myosin motor, and further our understanding of the motile apparatus underlying gliding motility in apicomplexan parasites.
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Nguyen, HoangKim T., Jaspreet Sandhu, Gerasimos Langousis, and Kent L. Hill. "CMF22 Is a Broadly Conserved Axonemal Protein and Is Required for Propulsive Motility in Trypanosoma brucei." Eukaryotic Cell 12, no. 9 (July 12, 2013): 1202–13. http://dx.doi.org/10.1128/ec.00068-13.
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ABSTRACT The eukaryotic flagellum (or cilium) is a broadly conserved organelle that provides motility for many pathogenic protozoa and is critical for normal development and physiology in humans. Therefore, defining core components of motile axonemes enhances understanding of eukaryotic biology and provides insight into mechanisms of inherited and infectious diseases in humans. In this study, we show that component of motile flagella 22 (CMF22) is tightly associated with the flagellar axoneme and is likely to have been present in the last eukaryotic common ancestor. The CMF22 amino acid sequence contains predicted IQ and A TPase a ssociated with a variety of cellular a ctivities (AAA) motifs that are conserved among CMF22 orthologues in diverse organisms, hinting at the importance of these domains in CMF22 function. Knockdown by RNA interference (RNAi) and rescue with an RNAi-immune mRNA demonstrated that CMF22 is required for propulsive cell motility in Trypanosoma brucei . Loss of propulsive motility in CMF22-knockdown cells was due to altered flagellar beating patterns, rather than flagellar paralysis, indicating that CMF22 is essential for motility regulation and likely functions as a fundamental regulatory component of motile axonemes. CMF22 association with the axoneme is weakened in mutants that disrupt the nexin-dynein regulatory complex, suggesting potential interaction with this complex. Our results provide insight into the core machinery required for motility of eukaryotic flagella.
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Matz, Carsten, and Klaus Jürgens. "High Motility Reduces Grazing Mortality of Planktonic Bacteria." Applied and Environmental Microbiology 71, no. 2 (February 2005): 921–29. http://dx.doi.org/10.1128/aem.71.2.921-929.2005.
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ABSTRACT We tested the impact of bacterial swimming speed on the survival of planktonic bacteria in the presence of protozoan grazers. Grazing experiments with three common bacterivorous nanoflagellates revealed low clearance rates for highly motile bacteria. High-resolution video microscopy demonstrated that the number of predator-prey contacts increased with bacterial swimming speed, but ingestion rates dropped at speeds of >25 μm s−1 as a result of handling problems with highly motile cells. Comparative studies of a moderately motile strain (<25 μm s−1) and a highly motile strain (>45 μm s−1) further revealed changes in the bacterial swimming speed distribution due to speed-selective flagellate grazing. Better long-term survival of the highly motile strain was indicated by fourfold-higher bacterial numbers in the presence of grazing compared to the moderately motile strain. Putative constraints of maintaining high swimming speeds were tested at high growth rates and under starvation with the following results: (i) for two out of three strains increased growth rate resulted in larger and slower bacterial cells, and (ii) starved cells became smaller but maintained their swimming speeds. Combined data sets for bacterial swimming speed and cell size revealed highest grazing losses for moderately motile bacteria with a cell size between 0.2 and 0.4 μm3. Grazing mortality was lowest for cells of >0.5 μm3 and small, highly motile bacteria. Survival efficiencies of >95% for the ultramicrobacterial isolate CP-1 (≤0.1 μm3, >50 μm s−1) illustrated the combined protective action of small cell size and high motility. Our findings suggest that motility has an important adaptive function in the survival of planktonic bacteria during protozoan grazing.
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AL-Janabi, Mohammed Hashim, Hazim I. Al-Ahmed, and Zaid A. Thabit. "The effect of cell-free supernatant (CFS) of Escherichia coli on human sperm motility." Journal of Biotechnology Research Center 12, no. 2 (June 1, 2018): 32–35. http://dx.doi.org/10.24126/jobrc.2018.12.2.535.
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Escherichia coli were isolated from vaginal and cervical samples during vaginal examination. Fifteen semen samples have been gathered through masturbation after three days of sexual abstinence. The Cell-Free Supernatant (CFS) of Escherichia has been collected by removing the cells from overnight broth cultures and filtered. The effect of (CFS) of Escherichia coli on spermatozoa motility was determined by using Earl’s balanced solution to prepare1:2 to 1:16 dilutions of CSF. Results conducted there was a significant difference in the count number of motile spermatozoa in 15 seminal fluid samples after being treated with CSF at the dilutions1:2 (p≤0.05) ,1:4 (p≤0.05) and 1:8(p≤0.05). The experiment showed a successive significant increase in the count number of motile sperms compatible with the lowering concentration of CSF until the count number of motile sperms reached the highest in the fourth dilution 1:16 ( P≥0.05) . This demonstrates the real effect of CSF on the vitality and activity of sperm. On the other hand, the study showed that the Escherichia Coli, causing genital tract infection, could have a bad effect on the motility and transportation of men’s spermatozoa and might be responsible for infertility.
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BRENT HEATH, I. "Evidence Against a Direct Role for Cortical Actin Arrays in Saltatory Organelle Motility in Hyphae of the Fungus Saprolegnia Ferax." Journal of Cell Science 91, no. 1 (September 1, 1988): 41–47. http://dx.doi.org/10.1242/jcs.91.1.41.
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Actin stained by rhodamine-labelled phalloidin in growing hyphae of the oomycete fungus Saprolegnia ferax is restricted to an approximately 0.25 μm deep layer of the cell periphery where it forms an apical cap of fine filaments and a subapical array of coarser longitudinal fibrils interspersed with plaques. The functions of this actin are unknown, but because actin-rich fibrils in other cells are involved in organelle motility I have sought evidence for a similar role in these hyphae. The most prominent motile structures are a population of spherical, predominantly sub-micrometre diameter, refractile vesicles of unknown function, which show typical saltatory movements along the hyphae. The motility of these vesicles is statistically identical in both the central cytoplasm, remote from the actin fibrils, and the peripheral cytoplasm adjacent to the fibrils. Treatment of hyphae with specific concentrations and durations of the detergents Tween 20 and Brij 58 causes extensive reorganization of the actin arrays with no effect on vesicle motility, whereas Triton X-100 severely inhibits motility with little detectable effect on the actin filaments. These observations show that normal vesicle motility does not depend on the proximity of a normal population of actin filaments and, therefore, suggest that the latter have some function other than a direct role in saltatory organelle motility.
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Tozluoglu, Melda, Yanlan Mao, Paul A. Bates, and Erik Sahai. "Cost–benefit analysis of the mechanisms that enable migrating cells to sustain motility upon changes in matrix environments." Journal of The Royal Society Interface 12, no. 106 (May 2015): 20141355. http://dx.doi.org/10.1098/rsif.2014.1355.
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Cells can move through extracellular environments with varying geometries and adhesive properties. Adaptation to these differences is achieved by switching between different modes of motility, including lamellipod-driven and blebbing motility. Further, cells can modulate their level of adhesion to the extracellular matrix (ECM) depending on both the level of force applied to the adhesions and cell intrinsic biochemical properties. We have constructed a computational model of cell motility to investigate how motile cells transition between extracellular environments with varying surface continuity, confinement and adhesion. Changes in migration strategy are an emergent property of cells as the ECM geometry and adhesion changes. The transition into confined environments with discontinuous ECM fibres is sufficient to induce shifts from lamellipod-based to blebbing motility, while changes in confinement alone within a continuous geometry are not. The geometry of the ECM facilitates plasticity, by inducing shifts where the cell has high marginal gain from a mode change, and conserving persistency where the cell can continue movement regardless of the motility mode. This regulation of cell motility is independent of global changes in cytoskeletal properties, but requires locally higher linkage between the actin network and the plasma membrane at the cell rear, and changes in internal cell pressure. In addition to matrix geometry, we consider how cells might transition between ECM of different adhesiveness. We find that this requires positive feedback between the forces cells apply on the adhesion points, and the strength of the cell–ECM adhesions on those sites. This positive feedback leads to the emergence of a small number of highly adhesive cores, similar to focal adhesions. While the range of ECM adhesion levels the cell can invade is expanded with this feedback mechanism; the velocities are lowered for conditions where the positive feedback is not vital. Thus, plasticity of cell motility sacrifices the benefits of specialization, for robustness.
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Lux, Renate, James N. Miller, No-Hee Park, and Wenyuan Shi. "Motility and Chemotaxis in Tissue Penetration of Oral Epithelial Cell Layers by Treponema denticola." Infection and Immunity 69, no. 10 (October 1, 2001): 6276–83. http://dx.doi.org/10.1128/iai.69.10.6276-6283.2001.
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ABSTRACT The ability to penetrate tissue is an important virulence factor for pathogenic spirochetes. Previous studies have recognized the role of motility in allowing pathogenic spirochetes to invade tissues and migrate to sites favorable for bacterial proliferation. However, the nature of the movements, whether they are random or controlled by chemotaxis systems, has yet to be established. In this study, we addressed the role of motility and chemotaxis in tissue penetration by the periodontal disease-associated oral spirochete Treponema denticola using an oral epithelial cell line-based experimental approach. Wild-type T. denticola ATCC 35405 was found to penetrate the tissue layers effectively, whereas a nonmotile mutant was unable to overcome the tissue barrier. Interestingly, the chemotaxis mutants also showed impaired tissue penetration. AcheA mutant that is motile but lacks the central kinase of the chemotaxis pathway showed only about 2 to 3% of the wild-type penetration rate. The two known chemoreceptors of T. denticola, DmcA and DmcB, also appear to be involved in the invasion process. The dmc mutants were actively motile but exhibited reduced tissue penetration of about 30 and 10% of the wild-type behavior, respectively. These data suggest that not only motility but also chemotaxis is involved in the tissue penetration byT. denticola.