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61.
Wei-Ting Liu Yu-Liang Yang Yuquan Xu Anne Lamsa Nina M. Haste Jane Y. Yang Julio Ng David Gonzalez Craig D. Ellermeier Paul D. Straight Pavel A. Pevzner Joe Pogliano Victor Nizet Kit Pogliano Pieter C. Dorrestein 《Proceedings of the National Academy of Sciences of the United States of America》2010,107(37):16286-16290
During bacterial cannibalism, a differentiated subpopulation harvests nutrients from their genetically identical siblings to allow continued growth in nutrient-limited conditions. Hypothesis-driven imaging mass spectrometry (IMS) was used to identify metabolites active in a Bacillus subtilis cannibalism system in which sporulating cells lyse nonsporulating siblings. Two candidate molecules with sequences matching the products of skfA and sdpC, genes for the proposed cannibalistic factors sporulation killing factor (SKF) and sporulation delaying protein (SDP), respectively, were identified and the structures of the final products elucidated. SKF is a cyclic 26-amino acid (aa) peptide that is posttranslationally modified with one disulfide and one cysteine thioether bridged to the α-position of a methionine, a posttranslational modification not previously described in biology. SDP is a 42-residue peptide with one disulfide bridge. In spot test assays on solid medium, overproduced SKF and SDP enact a cannibalistic killing effect with SDP having higher potency. However, only purified SDP affected B. subtilis cells in liquid media in fluorescence microscopy and growth assays. Specifically, SDP treatment delayed growth in a concentration-dependent manner, caused increases in cell permeability, and ultimately caused cell lysis accompanied by the production of membrane tubules and spheres. Similarly, SDP but not SKF was able to inhibit the growth of the pathogens Staphylococcus aureus and Staphylococcus epidermidis with comparable IC50 to vancomycin. This investigation, with the identification of SKF and SDP structures, highlights the strength of IMS in investigations of metabolic exchange of microbial colonies and also demonstrates IMS as a promising approach to discover novel biologically active molecules. 相似文献
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In fMRI, subject motion can severely affect data quality. This is a particular problem when movement is correlated with the experimental paradigm as this potentially causes artefactual activation. A method is presented that uses linear regression, to utilise the time course of an image acquired at very short echo time (TE) as a voxel‐wise regressor for a second image in the same echo train, that is acquired with high BOLD sensitivity. The value of this approach is demonstrated using task‐locked motion combined with visual stimulation. Results obtained at both 1.5 and 3 T show improvements in functional activation maps for individual subjects. The method is straightforward to implement, does not require extra scan time and can easily be embedded in a multi‐echo acquisition framework. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
64.
Resistance of rat hepatocytes against bile acid-induced apoptosis in cholestatic liver injury is due to nuclear factor-kappa B activation 总被引:3,自引:0,他引:3
65.
David Mutimer Nicolai Naoumov Pieter Honkoop George Marinos Monz Ahmed Robert de Man Penny McPhillips Mark Johnson Roger Williams Elwyn Elias Solko Schalm 《Journal of hepatology》1998,28(6):923-929
Background/Aims: Alpha-interferon achieves seroconversion in about one third of naive patients. Attempts to achieve seroconversion in patients who have previously failed alpha-interferon have proved disappointing. Combination chemotherapy (alpha-interferon with a nucleoside analogue) might provide a treatment alternative for these patients. We have undertaken a phase 2 study in 20 patients who had previously failed at least one course of alpha-interferon. The study was designed to assess the safety, tolerability and efficacy of the combination.Methods: All patients were treated for 16 weeks with alpha-interferon in combination with 12 or 16 weeks of Lamivudine (3′TC). Patients were followed for 16 weeks post-treatment. Pharmacokinetic studies were performed to identify/exclude significant pharmacokinetic drug interaction.Results: The combination was well tolerated, and side-effects of the combination were indistinguishable from the recognised side-effects of alpha-interferon. Pharmacokinetic studies performed on days 1 and 29 did not show any significant interaction. All patients achieved HBV DNA clearance during treatment, but 19 relapsed at the end of treatment. HBeAg/anti-HBe seroconversion was observed for four patients, but was sustained for a single patient (who also had sustained DNA clearance).Conclusions: Combination therapy with alpha-interferon and lamivudine given for 16 weeks appears safe and is well tolerated. However, for this group of patients who had previously failed interferon monotheraphy appears disappointing, and other treatment strategies should be investigated. 相似文献
66.
Benoit D Decruyenaere J Depuydt P Colpaert K 《Lancet》2004,363(9403):170; author reply 170-170; author reply 171
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68.
Background
Although bacterial cholangitis is frequently mentioned as a cause of secondary sclerosing cholangitis, it appears to be extremely rare, with only one documented case ever reported. 相似文献69.
Esther M. Wesselink MD Masieh Abawi MD PhD Nynke H. M. Kooistra MD PhD Teus H. Kappen MD PhD Pierfrancesco Agostoni MD PhD Marielle Emmelot-Vonk MD PhD Wietze Pasma PhD Wilton A. van Klei MD PhD Romy C. van Jaarsveld MSc Charlotte S. van Dongen MSc Pieter A. F. M. Doevendans MD PhD Arjen J. C. Slooter MD PhD Pieter R. Stella MD PhD 《Journal of the American Geriatrics Society》2021,69(11):3177-3185
70.
Neurocognitive predictors of substance use disorders and nicotine dependence in ADHD probands,their unaffected siblings,and controls: a 4‐year prospective follow‐up 下载免费PDF全文