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Shanli Mou Xiaowen Zhang Naihao Ye Jinlai Miao Shaona Cao Dong Xu Xiao Fan Meiling An 《Extremophiles : life under extreme conditions》2013,17(3):477-484
Non-photochemical fluorescence quenching (NPQ) is mainly associated with the transthylakoid proton gradient (ΔpH) and xanthophyll cycle. However, the exact mechanism of NPQ is different in different oxygenic photosynthetic organisms. In this study, several inhibitors were used to study NPQ kinetics in the sea ice alga Chlamydomonas sp. ICE-L and to determine the functions of ΔpH and the xanthophyll cycle in the NPQ process. NH4Cl and nigericin, uncouplers of ΔpH, inhibited NPQ completely and zeaxanthin (Z) was not detected in 1 mM NH4Cl-treated samples. Moreover, Z and NPQ were increased in the samples containing N,N’-dicyclohexyl-carbodiimide (DCCD) under low light conditions. We conclude that ΔpH plays a major role in NPQ, and activation of the xanthophyll cycle is related to ΔpH. In dithiothreitol (DTT)-treated samples, no Z was observed and NPQ decreased. NPQ was completely inhibited when NH4Cl was added suggesting that part of the NPQ process is related to the xanthophyll cycle and the remainder depends on ΔpH. Moreover, lutein and β-carotene were also essential for NPQ. These results indicate that NPQ in the sea ice alga Chlamydomonas sp. ICE-L is mainly dependent on ΔpH which affects the protonation of PSII proteins and de-epoxidation of the xanthophyll cycle, and the transthylakoid proton gradient alone can induce NPQ. 相似文献
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生物类专业基础课“生物化学”课程思政教育探索与创新 总被引:1,自引:0,他引:1
专业课教学中渗透思政教育是实现高校全过程、全方位、全员育人的重要途径,而且以专业知识为载体的思政教育比纯粹的思政课更有说服力和感染力。生物化学作为生物类专业的基础必修课,蕴含着丰富多样的思政资源。近年来,我们教学团队结合“生物化学”课程自身特征,开展了颇有成效的课程思政教学探索与实践,明确了课程育人目标,丰富了课程教学资源,创新了课程教学模式,构建了思政融合策略。思政资源的深度挖掘和巧妙应用收获了“润物细无声”的效果,实现了“生物化学”课程教学价值塑造、知识传授与能力培养的三者有机结合。 相似文献
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Xiaowen Liu Yakov Sirotkin Yufeng Shen Gordon Anderson Yihsuan S. Tsai Ying S. Ting David R. Goodlett Richard D. Smith Vineet Bafna Pavel A. Pevzner 《Molecular & cellular proteomics : MCP》2012,11(6)
In the last two years, because of advances in protein separation and mass spectrometry, top-down mass spectrometry moved from analyzing single proteins to analyzing complex samples and identifying hundreds and even thousands of proteins. However, computational tools for database search of top-down spectra against protein databases are still in their infancy. We describe MS-Align+, a fast algorithm for top-down protein identification based on spectral alignment that enables searches for unexpected post-translational modifications. We also propose a method for evaluating statistical significance of top-down protein identifications and further benchmark various software tools on two top-down data sets from Saccharomyces cerevisiae and Salmonella typhimurium. We demonstrate that MS-Align+ significantly increases the number of identified spectra as compared with MASCOT and OMSSA on both data sets. Although MS-Align+ and ProSightPC have similar performance on the Salmonella typhimurium data set, MS-Align+ outperforms ProSightPC on the (more complex) Saccharomyces cerevisiae data set.In the past two decades, proteomics was dominated by bottom-up mass spectrometry that analyzes digested peptides rather than intact proteins. Bottom-up approaches, although powerful, do have limitations in analyzing protein species, e.g. various proteolytic forms of the same protein or various protein isoforms resulting from alternative splicing. Top-down mass spectrometry focuses on analyzing intact proteins and large peptides (1–10) and has advantages in localizing multiple post-translational modifications (PTMs)1 in a coordinated fashion (e.g. combinatorial PTM code) and identifying multiple protein species (e.g. proteolytically processed protein species) (11). Until recently, most top-down studies were limited to single purified proteins (12–15). Top-down studies of protein mixtures were restricted by difficulties in separating and fragmenting intact proteins and a shortage of robust computational tools.In the last two years, because of advances in protein separation and top-down instrumentation, top-down mass spectrometry moved from analyzing single proteins to analyzing complex samples containing hundreds and even thousands of proteins (16–21). Because algorithms for interpreting top-down spectra are still in their infancy, many recent developments include computational innovations in protein identification.Because top-down spectra are complex, the first step in top-down spectral interpretation is usually spectral deconvolution, which converts a complex top-down spectrum to a list of monoisotopic masses (a deconvolved spectrum). Every protein (possibly with modifications) can be scored against a top-down deconvoluted spectrum, resulting in a Protein-Spectrum-Match (PrSM). The top-down protein identification problem is finding a protein in a database with the highest scoring PrSM for a top-down spectrum and further output the PrSM if it is statistically significant. There are several software tools for top-down protein identification (Software Identification of unexpected modifications Proteogenomics search against 6-frame translation Speed Estimation of statistical significance ProSightPC +/−a + Fast/Slowb + PIITA +/− − Fast − UStag + + Fast − MS-TopDown + − Slow − MS-Align+ + + Fast +