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71.
Gunilla Frykholm Bengt Glimelius Sven Richter Jörgen Carlsson 《In vitro cellular & developmental biology. Animal》1991,27(12):900-906
Summary A panel of human colon carcinoma cell lines were characterized regarding both antigenic heterogeneity and variations in radiosensitivity.
Monoclonal antibodies were used to study the expression of carcinoembryonic antigen (CEA), gastrointestinal cancer antigen
(GICA or CA 19-9) and carcinoma-associated antigen (CA-50). Radiosensitivity was studied with the clonogenic survival technique.
Three cell lines, LS 174T, HCTC, and SW 1116 stained positive for all three antigens. HT-29 was positive for CA 19-9 and CA-50
whereas Caco-2 was positive for CEA and CA 19-9. The cell lines SW 620 and LIM 1215 only stained positive for one of the antigens,
CA-50 and CEA, respectively. In nearly all positive cases the stainings were very heterogeneous with mixtures of positive
and negative cells. One exception was the HCTC cells which stained homogeneously for the CA 19-9 and CA-50 antigens. The neuroendocrinelike
COLO 320 cells were negative in all cases. The radiosensitivity varied strongly between the cell lines with Dq-values between 0.8 and 1.9, extrapolation numbers between 2.0 and 4.7, Do-values between 1.1 and 2.8. The surviving fraction at 2 Gy varied between 0.3 and 0.7 with HCTC as the most radiosensitive
and HT-29 as the most radioresistant cell line. Thus, there were differences in antigenic expression and intrinsic radiosensitivity
between the cell-lines and antigenic heterogeneities within each cell line. The analyzed panel of cell lines will be valuable
in studies of dose-effect relations for monoclonal antibodies labeled with toxic radionuclides simulating both antigenic heterogeneity
and variations in radiosensitivity. 相似文献
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73.
Toni Meier Karolin Senftleben Peter Deumelandt Olaf Christen Katja Riedel Martin Langer 《PloS one》2015,10(9)
Non-communicable diseases (NCDs) represent not only the major driver for quality-restricted and lost life years; NCDs and their related medical treatment costs also pose a substantial economic burden on healthcare and intra-generational tax distribution systems. The main objective of this study was therefore to quantify the economic burden of unbalanced nutrition in Germany—in particular the effects of an excessive consumption of fat, salt and sugar—and to examine different reduction scenarios on this basis. In this study, the avoidable direct cost savings in the German healthcare system attributable to an adequate intake of saturated fatty acids (SFA), salt and sugar (mono- & disaccharides, MDS) were calculated. To this end, disease-specific healthcare cost data from the official Federal Health Monitoring for the years 2002–2008 and disease-related risk factors, obtained by thoroughly searching the literature, were used. A total of 22 clinical endpoints with 48 risk-outcome pairs were considered. Direct healthcare costs attributable to an unbalanced intake of fat, salt and sugar are calculated to be 16.8 billion EUR (CI95%: 6.3–24.1 billion EUR) in the year 2008, which represents 7% (CI95% 2%-10%) of the total treatment costs in Germany (254 billion EUR). This is equal to 205 EUR per person annually. The excessive consumption of sugar poses the highest burden, at 8.6 billion EUR (CI95%: 3.0–12.1); salt ranks 2nd at 5.3 billion EUR (CI95%: 3.2–7.3) and saturated fat ranks 3rd at 2.9 billion EUR (CI95%: 32 million—4.7 billion). Predicted direct healthcare cost savings by means of a balanced intake of sugars, salt and saturated fat are substantial. However, as this study solely considered direct medical treatment costs regarding an adequate consumption of fat, salt and sugars, the actual societal and economic gains, resulting both from direct and indirect cost savings, may easily exceed 16.8 billion EUR. 相似文献
74.
Production of a recombinant polyester-cleaving hydrolase from Thermobifida fusca in Escherichia coli 总被引:1,自引:0,他引:1
Dresler K van den Heuvel J Müller RJ Deckwer WD 《Bioprocess and biosystems engineering》2006,29(3):169-183
The hydrolase (Thermobifida fusca hydrolase; TfH) from T. fusca was produced in Escherichia coli as fusion protein using the OmpA leader sequence and a His6 tag. Productivity could be raised more than 100-fold. Both batch and fed-batch cultivations yield comparable cell specific productivities whereas volumetric productivities differ largely. In the fed-batch cultivations final rTfH concentrations of 0.5 g L−1 could be achieved. In batch cultivations the generated rTfH is translocated to the periplasm wherefrom it is completely released into the extracellular medium. In fed-batch runs most of the produced rTfH remains as soluble protein in the cytoplasm and only a fraction of about 35% is translocated to the periplasm. Migration of periplasmic proteins in the medium is obviously coupled with growth rate and this final transport step possibly plays an important role in product localization and efficacy of the Sec translocation process. 相似文献
75.
Nucleosomes are highly dynamic macromolecular complexes that are assembled and disassembled in a modular fashion. One important way in which this dynamic process can be modulated is by the replacement of major histones with their variants, thereby affecting nucleosome structure and function. Here we use fluorescence resonance energy transfer between fluorophores attached to various defined locations within the nucleosome to dissect and compare the structural transitions of a H2A.Z containing and a canonical nucleosome in response to increasing ionic strength. We show that the peripheral regions of the DNA dissociate from the surface of the histone octamer at relatively low ionic strength, under conditions where the dimer-tetramer interaction remains unaffected. At around 550 mm NaCl, the (H2A-H2B) dimer dissociates from the (H3-H4)(2) tetramer-DNA complex. Significantly, this latter transition is stabilized in nucleosomes that have been reconstituted with the essential histone variant H2A.Z. Our studies firmly establish fluorescence resonance energy transfer as a valid method to study nucleosome stability, and shed new light on the biological function of H2A.Z. 相似文献
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78.
Chin-Chi Chen Mekonnen Lemma Dechassa Emily Bettini Mary B. Ledoux Christian Belisario Patrick Heun Karolin Luger Barbara G. Mellone 《The Journal of cell biology》2014,204(3):313-329
Centromeres are specified epigenetically by the incorporation of the histone H3 variant CENP-A. In humans, amphibians, and fungi, CENP-A is deposited at centromeres by the HJURP/Scm3 family of assembly factors, but homologues of these chaperones are absent from a number of major eukaryotic lineages such as insects, fish, nematodes, and plants. In Drosophila, centromeric deposition of CENP-A requires the fly-specific protein CAL1. Here, we show that targeting CAL1 to noncentromeric DNA in Drosophila cells is sufficient to heritably recruit CENP-A, kinetochore proteins, and microtubule attachments. CAL1 selectively interacts with CENP-A and is sufficient to assemble CENP-A nucleosomes that display properties consistent with left-handed octamers. The CENP-A assembly activity of CAL1 resides within an N-terminal domain, whereas the C terminus mediates centromere recognition through an interaction with CENP-C. Collectively, this work identifies the “missing” CENP-A chaperone in flies, revealing fundamental conservation between insect and vertebrate centromere-specification mechanisms. 相似文献
79.
Karolin Wellner Heike Betat Mario Mörl 《Biochimica et Biophysica Acta (BBA) - Gene Regulatory Mechanisms》2018,1861(4):433-441
tRNAs are key players in translation and are additionally involved in a wide range of distinct cellular processes. The vital importance of tRNAs becomes evident in numerous diseases that are linked to defective tRNA molecules. It is therefore not surprising that the structural intactness of tRNAs is continuously scrutinized and defective tRNAs are eliminated. In this process, erroneous tRNAs are tagged with single-stranded RNA sequences that are recognized by degrading exonucleases. Recent discoveries have revealed that the CCA-adding enzyme – actually responsible for the de novo synthesis of the 3′-CCA end – plays an indispensable role in tRNA quality control by incorporating a second CCA triplet that is recognized as a degradation tag. In this review, we give an update on the latest findings regarding tRNA quality control that turns out to represent an interplay of the CCA-adding enzyme and RNases involved in tRNA degradation and maturation. In particular, the RNase-induced turnover of the CCA end is now recognized as a trigger for the CCA-adding enzyme to repeatedly scrutinize the structural intactness of a tRNA. This article is part of a Special Issue entitled: SI: Regulation of tRNA synthesis and modification in physiological conditions and disease edited by Dr. Boguta Magdalena. 相似文献
80.
Karolin Klement Martijn S. Luijsterburg Jordan B. Pinder Chad S. Cena Victor Del Nero Christopher M. Wintersinger Graham Dellaire Haico van Attikum Aaron A. Goodarzi 《The Journal of cell biology》2014,207(6):717-733
Heterochromatin is a barrier to DNA repair that correlates strongly with elevated somatic mutation in cancer. CHD class II nucleosome remodeling activity (specifically CHD3.1) retained by KAP-1 increases heterochromatin compaction and impedes DNA double-strand break (DSB) repair requiring Artemis. This obstruction is alleviated by chromatin relaxation via ATM-dependent KAP-1S824 phosphorylation (pKAP-1) and CHD3.1 dispersal from heterochromatic DSBs; however, how heterochromatin compaction is actually adjusted after CHD3.1 dispersal is unknown. In this paper, we demonstrate that Artemis-dependent DSB repair in heterochromatin requires ISWI (imitation switch)-class ACF1–SNF2H nucleosome remodeling. Compacted chromatin generated by CHD3.1 after DNA replication necessitates ACF1–SNF2H–mediated relaxation for DSB repair. ACF1–SNF2H requires RNF20 to bind heterochromatic DSBs, underlies RNF20-mediated chromatin relaxation, and functions downstream of pKAP-1–mediated CHD3.1 dispersal to enable DSB repair. CHD3.1 and ACF1–SNF2H display counteractive activities but similar histone affinities (via the plant homeodomains of CHD3.1 and ACF1), which we suggest necessitates a two-step dispersal and recruitment system regulating these opposing chromatin remodeling activities during DSB repair. 相似文献