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151.
152.
Temmink Ralph J. M. Dorenbosch Martijn Lamers Leon P. M. Smolders Alfons J. P. Rip Winnie Lengkeek Wouter Didderen Karin Fivash Gregory S. Bouma Tjeerd J. van der Heide Tjisse 《Hydrobiologia》2021,848(17):3987-3999
Hydrobiologia - Aquatic ecosystems provide vital services, and macrophytes play a critical role in their functioning. Conceptual models indicate that in shallow lakes, plants with different growth... 相似文献
153.
Pratiti Bhadra Lalitha Yadhanapudi Karin Rmisch Volkhard Helms 《PLoS computational biology》2021,17(3)
The Sec complex catalyzes the translocation of proteins of the secretory pathway into the endoplasmic reticulum and the integration of membrane proteins into the endoplasmic reticulum membrane. Some substrate peptides require the presence and involvement of accessory proteins such as Sec63. Recently, a structure of the Sec complex from Saccharomyces cerevisiae, consisting of the Sec61 channel and the Sec62, Sec63, Sec71 and Sec72 proteins was determined by cryo-electron microscopy (cryo-EM). Here, we show by co-precipitation that the Sec61 channel subunit Sbh1 is not required for formation of stable Sec63-Sec61 contacts. Molecular dynamics simulations started from the cryo-EM conformation of Sec61 bound to Sec63 and of unbound Sec61 revealed how Sec63 affects the conformation of Sec61 lateral gate, plug, pore region and pore ring diameter via three intermolecular contact regions. Molecular docking of SRP-dependent vs. SRP-independent signal peptide chains into the Sec61 channel showed that the pore regions affected by presence/absence of Sec63 play a crucial role in positioning the signal anchors of SRP-dependent substrates nearby the lateral gate. 相似文献
154.
β-Glucan process-related impurities can be introduced into biopharmaceutical products via upstream or downstream processing or via excipients. This study obtained a comprehensive process-mapping dataset for five monoclonal antibodies to assess β-glucan introduction and clearance during development and production runs at various scales. Overall, 198 data points were available for analysis. The greatest β-glucan concentrations were found in the depth-filtration filtrate (37–2,745 pg/ml). Load volume correlated with β-glucan concentration in the filtrate, whereas flush volume was of secondary importance. Cation-exchange chromatography significantly cleared β-glucans. Furthermore, β-glucan leaching from the Planova 20N virus removal filter was reduced by increasing the flush volume (1 vs. 10 L/m2). β-glucan concentrations after filter flush with 10 L/m2 were consistently <10 pg/ml. No or only limited β-glucan clearance was attained via ultrafiltration/diafiltration (UF/DF). However, during the first run with monoclonal antibody (mAb) 4, β-glucan concentration in the UF/DF retentate was 10.8 pg/mg, potentially due to β-glucan leaching from the first run with a regenerated cellulose membrane. Overall, β-glucan levels in the final mAb drug substance were 1–12 pg/mg. Assuming high doses of 1,000–5,000 mg, a β-glucan contamination at 20 pg/mg would translate to 20–100 ng/dose, which is below the previously suggested threshold for product safety (≤500 ng/dose). 相似文献
155.
Karin Müller Keri L.H. Carpenter Iain R. Challis Jeremy N. Skepper Mark J. Arends 《Free radical research》2013,47(7):791-802
Epidemiologically, a high-carotenoid intake via a fruit- and vegetable-rich diet is associated with a decreased risk of various forms of cancer. The mechanisms by which carotenoids exert this protective effect are controversial. In this study, we examined the potency of a range of carotenoids commonly found in human plasma to induce apoptosis in Jurkat E6.1 malignant T-lymphoblast cells. At a concentration of 20 w M, the order of potency to induce apoptosis after 24 h was: g -carotene > lycopene > lutein> g -cryptoxanthin=zeaxanthin. Canthaxanthin failed to induce apoptosis under these conditions. g -Carotene induced apoptosis in a time- and concentration-dependent manner with a lowest effective concentration of about 3 w M. Pre-conditioning of g -carotene for 72 h destroyed its pro-apoptotic activity almost completely, whereas degradation for 6 h or less did not, indicating that either g -carotene itself and/or an early degradation product of g -carotene are the death-inducing compounds. Apoptosis induced by g -carotene was characterized by chromatin condensation and nuclear fragmentation, DNA degradation, PARP cleavage and caspase-3 activation. The antioxidant BO-653 inhibited the degradation of g -carotene in vitro and significantly increased its cytotoxicity, indicating that a pro-oxidant effect of g -carotene is unlikely to cause its pro-apoptotic activity. The induction of apoptosis in transformed cells by carotenoids may explain their protective effect against cancer formation in humans. Possible pathways for induction of apoptosis by carotenoids are discussed. 相似文献
156.
Induction of vitellogenin (Vtg) in oviparous vertebrates has been used as a biomarker of response for environmental oestrogens. This study reports the cellular localization of oestrogen- and xenoestrogen-induced Vtg synthesis in the liver of juvenile Atlantic salmon (Salmo salar). Paraffin-embedded liver sections were incubated with homologous monoclonal antibody against Atlantic salmon Vtg. Following intraperitoneal (ip) exposure of fish to estradiol-17beta E2; 5 mg kg-1 or 4-nonylphenol NP; 125 mg kg-1, Vtg induction was primarily demonstrated immunohistochemically in the cytoplasm of hepatocytes, endothelial cells and within hepatic sinusoids. Vtg staining of hepatocytes was not evenly distributed, as there was a high degree of polarization toward the sinusoid. The intensity of positive Vtg staining was stronger in the liver sections of E2-treated fish, compared with NP-treated fish. Hepatocytes of E2-, NP- and vehicle (control)-treated fish showed normal cellular structures, thus showing no evidence of histopathological changes. In parallel, indirect enzyme-linked immunosorbent assay (ELISA) and immunoblot analysis of plasma Vtg levels show significant induction of Vtg in E2- and NP-treated fish, as compared with untreated (control) fish. The present study demonstrates the applicability of immunohistochemistry in studies of cellular structures, processes and responses of fish exposure to oestrogen and oestrogen-mimicking compounds. 相似文献
157.
Joseph A. Webb Christopher P. Jones Leslie J. Parent Ioulia Rouzina Karin Musier-Forsyth 《RNA (New York, N.Y.)》2013,19(8):1078-1088
Despite the vast excess of cellular RNAs, precisely two copies of viral genomic RNA (gRNA) are selectively packaged into new human immunodeficiency type 1 (HIV-1) particles via specific interactions between the HIV-1 Gag and the gRNA psi (ψ) packaging signal. Gag consists of the matrix (MA), capsid, nucleocapsid (NC), and p6 domains. Binding of the Gag NC domain to ψ is necessary for gRNA packaging, but the mechanism by which Gag selectively interacts with ψ is unclear. Here, we investigate the binding of NC and Gag variants to an RNA derived from ψ (Psi RNA), as well as to a non-ψ region (TARPolyA). Binding was measured as a function of salt to obtain the effective charge (Zeff) and nonelectrostatic (i.e., specific) component of binding, Kd(1M). Gag binds to Psi RNA with a dramatically reduced Kd(1M) and lower Zeff relative to TARPolyA. NC, GagΔMA, and a dimerization mutant of Gag bind TARPolyA with reduced Zeff relative to WT Gag. Mutations involving the NC zinc finger motifs of Gag or changes to the G-rich NC-binding regions of Psi RNA significantly reduce the nonelectrostatic component of binding, leading to an increase in Zeff. These results show that Gag interacts with gRNA using different binding modes; both the NC and MA domains are bound to RNA in the case of TARPolyA, whereas binding to Psi RNA involves only the NC domain. Taken together, these results suggest a novel mechanism for selective gRNA encapsidation. 相似文献
158.
Thomas Schmiedinger Georg F. Vogel Oliver Eiter Kristian Pfaller Walter A. Kaufmann Angelika Flörl Karin Gutleben Sabine Schönherr Barbara Witting Thomas W. Lechleitner Hannes‐L. Ebner Thomas Seppi Michael W. Hess 《Traffic (Copenhagen, Denmark)》2013,14(8):886-894
Electrospun nanofibres are an excellent cell culture substrate, enabling the fast and non‐disruptive harvest and transfer of adherent cells for microscopical and biochemical analyses. Metabolic activity and cellular structures are maintained during the only half a minute‐long harvest and transfer process. We show here that such samples can be optimally processed by means of cryofixation combined either with freeze‐substitution, sample rehydration and cryosection‐immunolabelling or with freeze‐fracture replica‐immunolabelling. Moreover, electrospun fibre substrates are equally suitable for complementary approaches, such as biochemistry, fluorescence microscopy and cytochemistry. 相似文献
159.
Mahban Irandoust Julian Alvarez Zarate Isabelle Hubeek Ellen M. van Beek Karin Schornagel Aart J. F. Broekhuizen Mercan Akyuz Arjan A. van de Loosdrecht Ruud Delwel Peter J. Valk Edwin Sonneveld Pamela Kearns Ursula Creutzig Dirk Reinhardt Eveline S. J. M. de Bont Eva A. Coenen Marry M. van den Heuvel-Eibrink C. Michel Zwaan Gertjan J. L. Kaspers Jacqueline Cloos Timo K. van den Berg 《PloS one》2013,8(1)
Background
Recent studies show the importance of interactions between CD47 expressed on acute myeloid leukemia (AML) cells and the inhibitory immunoreceptor, signal regulatory protein-alpha (SIRPα) on macrophages. Although AML cells express SIRPα, its function has not been investigated in these cells. In this study we aimed to determine the role of the SIRPα in acute myeloid leukemia.Design and Methods
We analyzed the expression of SIRPα, both on mRNA and protein level in AML patients and we further investigated whether the expression of SIRPα on two low SIRPα expressing AML cell lines could be upregulated upon differentiation of the cells. We determined the effect of chimeric SIRPα expression on tumor cell growth and programmed cell death by its triggering with an agonistic antibody in these cells. Moreover, we examined the efficacy of agonistic antibody in combination with established antileukemic drugs.Results
By microarray analysis of an extensive cohort of primary AML samples, we demonstrated that SIRPα is differentially expressed in AML subgroups and its expression level is dependent on differentiation stage, with high levels in FAB M4/M5 AML and low levels in FAB M0–M3. Interestingly, AML patients with high SIRPα expression had a poor prognosis. Our results also showed that SIRPα is upregulated upon differentiation of NB4 and Kasumi cells. In addition, triggering of SIRPα with an agonistic antibody in the cells stably expressing chimeric SIRPα, led to inhibition of growth and induction of programmed cell death. Finally, the SIRPα-derived signaling synergized with the activity of established antileukemic drugs.Conclusions
Our data indicate that triggering of SIRPα has antileukemic effect and may function as a potential therapeutic target in AML. 相似文献160.