41,040 research outputs found
CHO microRNA engineering is growing up : recent successes and future challenges
No full textmicroRNAs with their ability to regulate complex pathways that control cellular behavior and phenotype have been proposed as potential targets for cell engineering in the context of optimization of biopharmaceutical production cell lines, specifically of Chinese Hamster Ovary cells. However, until recently, research was limited by a lack of genomic sequence information on this industrially important cell line. With the publication of the genomic sequence and other relevant data sets for CHO cells since 2011, the doors have been opened for an improved understanding of CHO cell physiology and for the development of the necessary tools for novel engineering strategies. In the present review we discuss both knowledge on the regulatory mechanisms of microRNAs obtained from other biological models and proof of concepts already performed on CHO cells, thus providing an outlook of potential applications of microRNA engineering in production cell lines
The polarized expression of Na+,K+-ATPase in epithelia depends on the association between beta-subunits located in neighboring cells
No full textThe polarized distribution of Na+,K+-ATPase plays a paramount physiological role, because either directly or through coupling with co- and countertransporters, it is responsible for the net movement of, for example, glucose, amino acids, Ca2+, K+, Cl-, and CO3H- across the whole epithelium. We report here that the beta-subunit is a key factor in the polarized distribution of this enzyme. 1) Madin-Darby canine kidney (MDCK) cells (epithelial from dog kidney) express the Na+,K+-ATPase over the lateral side, but not on the basal and apical domains, as if the contact with a neighboring cell were crucial for the specific membrane location of this enzyme. 2) MDCK cells cocultured with other epithelial types (derived from human, cat, dog, pig, monkey, rabbit, mouse, hamster, and rat) express the enzyme in all (100%) homotypic MDCK/MDCK borders but rarely in heterotypic ones. 3) Although MDCK cells never express Na+,K+-ATPase at contacts with Chinese hamster ovary (CHO) cells, they do when CHO cells are transfected with beta(1)-subunit from the dog kidney (CHO-beta). 4) This may be attributed to the adhesive property of the beta(1)-subunit, because an aggregation assay using CHO (mock-transfected) and CHO-beta cells shows that the expression of dog beta(1)-subunit in the plasma membrane does increase adhesiveness. 5) This adhesiveness does not involve adherens or tight junctions. 6) Transfection of beta(1)-subunit forces CHO-beta cells to coexpress endogenous a-subunit. Together, our results indicate that MDCK cells express Na+,K+-ATPase at a given border provided the contacting cell expresses the dog P,-subunit. The cell-cell interaction thus established would suffice to account for the polarized expression and positioning of Na+,K+-ATPase in epithelial cells
MULTIPOINT K-SPACE POINT MAPPING (KPM) TECHNIQUE FOR NMR MICROSCOPY
No full textAn extended version of point mapping in k-space for microscopic imaging applications is analyzed and described. Because the method can offer a number of advantages over the other conventional techniques due to the short echo time (TE), the technique is ideally suited for microscopic imaging where field inhomogeneity dependent signal degradation is one of the main causes of image resolution degradation (1-3). Another application area is the case of imaging in a highly inhomogeneous situation such as the fringe field imaging (Z.H. Cho, E. Wong, U.S. Patent #5023554 (1990). The first original point mapping technique described by Nauert at al. (1) and Emid and Creyghton (2) is analyzed as a k-space point mapping technique, and the original technique is extended to a multipoint k-space point mapping (MKPM) technique. With the extended MKPM technique, much faster microscopic imaging that is free of susceptibility and diffusion effects can be performed (4-6). To examine this idea, computer simulations are performed and their results are given
Erratum: 3D bioprinted in vitro secondary hyperoxaluria model by mimicking intestinal-oxalatemalabsorption-related kidney stone disease (Applied Physics Reviews (2022) 9 (041408) DOI: 10.1063/5.0087345)
No full text© 2023 Author(s).This article was originally published online on 21 November 2022 with an incorrect affiliation identifier for author Dong-Woo Cho. It is correct as it appears above. All online versions of this article were corrected on 23 November 2022. AIP Publishing apologizes for this error.11Nsciescopu
Structural and functional definition of the specificity of a novel caspase-3 inhibitor, Ac-DNLD-CHO-4
No full text<p><b>Copyright information:</b></p><p>Taken from "Structural and functional definition of the specificity of a novel caspase-3 inhibitor, Ac-DNLD-CHO"</p><p>http://www.biomedcentral.com/1471-2210/7/8</p><p>BMC Pharmacology 2007;7():8-8.</p><p>Published online 27 Jun 2007</p><p>PMCID:PMC1931592.</p><p></p>uation, log K= +0.56ΔG- 1.43
Unimodality of Betti numbers for Hamiltonian circle actions with index-increasing moment Maps
No full textThe unimodality conjecture posed by Tolman in [L. Jeffrey, T. Holm, Y. Karshon, E. Lerman and E. Meinrenken, Moment maps in various geometries, http://www.birs.ca/workshops/2005/05w5072/report05w5072.pdf] states that if (M,ω) is a 2n-dimensional smooth compact symplectic manifold equipped with a Hamiltonian circle action with only isolated fixed points, then the sequence of Betti numbers {b0(M),b2(M),...,b2n(M)} is unimodal, i.e. bi(M) ≤ bi+2(M) for every i < n. Recently, the author and Kim [Y. Cho and M. Kim, Unimodality of the Betti numbers for Hamiltonian circle action with isolated fixed points, Math. Res. Lett. 21(4) (2014) 691-696] proved that the unimodality holds in eight-dimensional case by using equivariant cohomology theory. In this paper, we generalize the idea in [Y. Cho and M. Kim, Unimodality of the Betti numbers for Hamiltonian circle action with isolated fixed points, Math. Res. Lett. 21(4) (2014) 691-696] to an arbitrary dimensional case. We prove the conjecture in arbitrary dimension under the assumption that the moment map H : M → R is index-increasing, which means that ind(p) < ind(q) implies H(p) < H(q) for every pair of critical points p and q of H, where ind(p) is the Morse index of p with respect to H. © World Scientific Publishing Company1111sciescopu
sj-docx-1-cho-10.1177_18632521221080477 – Supplemental material for Morscher’s femoral neck lengthening osteotomy through surgical hip dislocation approach for preservation of Perthes and Perthes-like deformities
No full textSupplemental material, sj-docx-1-cho-10.1177_18632521221080477 for Morscher’s femoral neck lengthening osteotomy through surgical hip dislocation approach for preservation of Perthes and Perthes-like deformities by Mostafa M Baraka, Hany M Hefny, Mootaz F Thakeb, Mahmoud A Mahran, Ahmed K El Ghazawy and Tamer A Fayyad in Journal of Children’s Orthopaedics</p
Onset of reversal and chaos thermally driven cavity flow
No full textWe investigate the onset of chaotic reversals of thermal convection cell in a two–dimensional square cavity using direct numerical simulation. To our knowledge, the chaotic reversal motion at the lowest Rayleigh number is related to the unicellular motion in this system. As Rayleigh number increases, the two antisymmetric attractors, which arise from the supercritical Hopf bifurcation, approach each other. However, because the basin boundaries of these attractors have multiple unstable directions, the behavior of the global changes seems to be complex for the small range of Rayleigh number around the onset of the chaotic reversal. On the other hand, period–doubling cascade from periodic reversal solutions leads to chaotic reversal as Rayleigh number decreases. At the conference we will report observation about the beginning of reversal and the quantities of the chaotic attractor
Intracellular trehalose via transporter TRET1 as a method to cryoprotect CHO-K1 cells
No full textTrehalose is a promising natural cryoprotectant, but its cryoprotective effect is limited due to difficulties in transmembrane transport. Thus, expressing the trehalose transporter TRET1 on various mammalian cells may yield more trehalose applications. In this study, we ran comparative cryopreservation experiments between the TRET1-expressing CHO-K1 cells (CHO-TRET1) and the CHO-K1 cells transfected with an empty vector (CHO-vector). The experiments involve freezing under various trehalose concentrations in an extracellular medium. The freeze-thawing viabilities of CHO-TRET1 cells are higher than those of CHO-vector cells for most freezing conditions. This result differs from control experiments with a transmembrane type cryoprotectant, dimethyl sulfoxide (Me2SO), which had similar viabilities in each condition for both cell types. We conclude that the trehalose loaded into the cells with TRET1 significantly improves the cryoprotective effect. The higher viabilities occurred when the extracellular trehalose concentration exceeded 200 mM, with 250-500 mM being optimal, and a cooling rate below 30 K/min, with 5-20 K/min being optimal
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