Selection of microcarrier diameter for the cultivation of mammalian cells on microcarriers

1987 ◽  
Vol 30 (4) ◽  
pp. 548-557 ◽  
Author(s):  
W.-S. Hu ◽  
D. I. C. Wang
Keyword(s):  
Mammalian Cells ◽  
Selection Of

A single-round selection of selective DNA aptamers for mammalian cells by polymer-enhanced capillary transient isotachophoresis

The Analyst ◽  
2017 ◽  
Vol 142 (21) ◽  
pp. 4030-4038 ◽  
Author(s):  
Kazuki Hirose ◽  
Maho Tsuchida ◽  
Hinako Asakura ◽  
Koji Wakui ◽  
Keitaro Yoshimoto ◽  
...  
Keyword(s):  
Capillary Electrophoresis ◽  
Mammalian Cells ◽  
Dna Aptamer ◽  
Dna Aptamers ◽  
Aptamer Selection ◽  
Selection For ◽  
First Time ◽  
Selection Of

A single-round DNA aptamer selection for mammalian cells was successfully achieved for the first time using a capillary electrophoresis (CE)-based methodology.

scholarly journals Selection of Transfected Mammalian Cells

2003 ◽  
Vol 62 (1) ◽  
Author(s):  
Richard Mortensen ◽  
Jonathan D. Chesnut ◽  
James P. Hoeffler ◽  
Robert E. Kingston
Keyword(s):  
Mammalian Cells ◽  
Selection Of

scholarly journals Selection of Retroviral Reverse Transcription Primer Is Coordinated with tRNA Biogenesis

2003 ◽  
Vol 77 (16) ◽  
pp. 8695-8701 ◽  
Author(s):  
Nathan J. Kelly ◽  
Matthew T. Palmer ◽  
Casey D. Morrow
Keyword(s):  
Reverse Transcription ◽  
Nuclear Export ◽  
Mammalian Cells ◽  
Leukemia Virus ◽  
Wild Type ◽  
Primer Selection ◽  
Yeast Trna ◽  
Trna Primer ◽  
Hiv 1 ◽  
Selection Of

ABSTRACT Initiation of retrovirus reverse transcription requires the selection of a tRNA primer from the intracellular milieu. To investigate the features of primer selection, a human immunodeficiency virus type 1 (HIV-1) and a murine leukemia virus (MuLV) were created that require yeast tRNAPhe to be supplied in trans for infectivity. Wild-type yeast tRNAPhe expressed in mammalian cells was transported to the cytoplasm and aminoacylated. In contrast, tRNAPhe without the D loop (tRNAPheD−) was retained within the nucleus and did not complement infectivity of either HIV-1 or MuLV; however, infectivity was restored when tRNAPheD− was directly transfected into the cytoplasm of cells. A tRNAPhe mutant (tRNAPheUUA) that did not have the capacity to be aminoacylated was transported to the cytoplasm and did complement infectivity of both HIV-1 and MuLV, albeit at a level less than that with wild-type tRNAPhe. Collectively, our results demonstrate that the tRNA primer captured by HIV-1 and MuLV occurs after nuclear export of tRNA and supports a model in which primer selection for retroviruses is coordinated with tRNA biogenesis at the intracellular site of protein synthesis.

Novel Method for Selection of tRNA-Driven Ribozymes with Enhanced Stability in Mammalian Cells

2002 ◽  
Vol 12 (5) ◽  
pp. 341-352 ◽  
Author(s):  
Masayuki Sano ◽  
Tomoko Kuwabara ◽  
Masaki Warashina ◽  
Akiyoshi Fukamizu ◽  
Kazunari Taira
Keyword(s):  
Mammalian Cells ◽  
Novel Method ◽  
Enhanced Stability ◽  
Selection Of

scholarly journals First person – Dipayan De

2021 ◽  
Vol 134 (11) ◽  
Keyword(s):  
Mammalian Cells ◽  
Chemical Biology ◽  
Amyloid Β ◽  
Indian Institute ◽  
Early Career ◽  
First Person ◽  
Early Career Researchers ◽  
Lysosomal Targeting ◽  
Selection Of ◽  
Cellular Organelles

ABSTRACT First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Dipayan De is first author on ‘ Amyloid-β oligomers block lysosomal targeting of miRNPs to prevent miRNP recycling and target repression in glial cells’, published in JCS. Dipayan is a PhD student in the lab of Dr Suvendra N. Bhattacharyya at the CSIR Indian Institute of Chemical Biology, Kolkata, India, investigating how cellular organelles regulate microRNA activity in mammalian cells.

scholarly journals Fusion and Hybridization of Marsupial and Eutherian Cells V. Development of Selective Systems

1978 ◽  
Vol 31 (3) ◽  
pp. 293 ◽  
Author(s):  
Rory M Hope ◽  
Jennifer A MarshalI Graves
Keyword(s):  
Mammalian Cells ◽  
Selective Medium ◽  
Drug Resistant ◽  
Purine Analogues ◽  
Inhibition Of Growth ◽  
Isolation And Characterization ◽  
Growth Properties ◽  
Cell Strains ◽  
Stable Characteristic ◽  
Selection Of

The availability of systems which permit the selective elimination of marsupial cells from fused cultures is an essential requirement for the production of marsupial x eutherian somatic cell hybrids. Such hybrids have particular advantages for genetic studies of mammalian cells. We describe the isolation and characterization of several drug-resistant marsupial cell strains. We have selected strains resistant to concentrations of 10 p,g/ml of the purine analogues 8-azaguanine and 6-thioguanine. Several of these strains were found to be deficient in the enzyme hypoxanthine phosphoribosyltransferase and consequently sensitive to hypoxanthine--aminopterin-thymidine (HAT) selective medium. We have also isolated marsupial cell strains resistant to concentrations of 22p,g/ml of the thymidine analogue 5-bromodeoxyuridine. These strains were thymidine kinase deficient and HAT sensitive. Drug resistance was a stable characteristic maintained for many generations in the absence of the drug. However, inhibition of growth of these drug-resistant strains was strongly density dependent, a factor that caused difficulties in the selection of hybrids. We have also developed selective systems which exploit differences between marsupial and eutherian cells in sensitivity to growth in ouabain, and in adhesiveness and other growth properties. Marsupial cells were found to be naturally much more sensitive to ouabain than rodent cells, a phenomenon that should be useful in the selection of marsupial x rodent cellular hybrids. We discuss a number of difficulties associated with the derivation and use of variant marsupial cell strains.

scholarly journals Directed Evolution of an Enhanced POU Reprogramming Factor for Cell Fate Engineering

2021 ◽  
Author(s):  
Daisylyn Senna Tan ◽  
Yanpu Chen ◽  
Ya Gao ◽  
Anastasia Bednarz ◽  
Yuanjie Wei ◽  
...  
Keyword(s):  
Directed Evolution ◽  
Cell Fate ◽  
Mammalian Cells ◽  
Phenotypic Selection ◽  
Biochemical Assays ◽  
Genome Wide ◽  
Dna Elements ◽  
Pioneer Factor ◽  
Selection Of

Abstract Transcription factor-driven cell fate engineering in pluripotency induction, transdifferentiation, and forward reprogramming requires efficiency, speed, and maturity for widespread adoption and clinical translation. Here, we used Oct4, Sox2, Klf4, and c-Myc driven pluripotency reprogramming to evaluate methods for enhancing and tailoring cell fate transitions, through directed evolution with iterative screening of pooled mutant libraries and phenotypic selection. We identified an artificially evolved and enhanced POU factor (ePOU) that substantially outperforms wild-type Oct4 in terms of reprogramming speed and efficiency. In contrast to Oct4, not only can ePOU induce pluripotency with Sox2 alone, but it can also do so in the absence of Sox2 in a three-factor ePOU/Klf4/c-Myc cocktail. Biochemical assays combined with genome-wide analyses showed that ePOU possesses a new preference to dimerize on palindromic DNA elements. Yet, the moderate capacity of Oct4 to function as a pioneer factor, its preference to bind octamer DNA and its capability to dimerize with Sox2 and Sox17 proteins remain unchanged in ePOU. Compared with Oct4, ePOU is thermodynamically stabilized and persists longer in reprogramming cells. In consequence, ePOU: 1) differentially activates several genes hitherto not implicated in reprogramming, 2) reveals an unappreciated role of thyrotropin-releasing hormone signaling, and 3) binds a distinct class of retrotransposons. Collectively, these features enable ePOU to accelerate the establishment of the pluripotency network. This demonstrates that the phenotypic selection of novel factor variants from mammalian cells with desired properties is key to advancing cell fate conversions with artificially evolved biomolecules.

Formation of heteroduplex DNA during mammalian intrachromosomal gene conversion

1992 ◽  
Vol 12 (4) ◽  
pp. 1546-1552
Author(s):  
R J Bollag ◽  
D R Elwood ◽  
E D Tobin ◽  
A R Godwin ◽  
R M Liskay
Keyword(s):  
Gene Conversion ◽  
Mammalian Cells ◽  
Restriction Site ◽  
Genetic Evidence ◽  
Heteroduplex Dna ◽  
Daughter Cells ◽  
Single Colony ◽  
Selection For ◽  
Restriction Site Polymorphisms ◽  
Selection Of

We have studied intrachromosomal gene conversion in mouse Ltk- cells with a substrate designed to provide genetic evidence for heteroduplex DNA. Our recombination substrate consists of two defective chicken thymidine kinase genes arranged so as to favor the selection of gene conversion products. The gene intended to serve as the recipient in gene conversion differs from the donor sequence by virtue of a palindromic insertion that creates silent restriction site polymorphisms between the two genes. While selection for gene conversion at a XhoI linker insertion within the recipient gene results in coconversion of the nearby palindromic site in more than half of the convertants, 4% of convertant colonies show both parental and nonparental genotypes at the polymorphic site. We consider these mixed colonies to be the result of genotypic sectoring and interpret this sectoring to be a consequence of unrepaired heteroduplex DNA at the polymorphic palindromic site. DNA replication through the heteroduplex recombination intermediate generates genetically distinct daughter cells that comprise a single colony. We believe that the data provide the first compelling genetic evidence for the presence of heteroduplex DNA during chromosomal gene conversion in mammalian cells.

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