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991.
992.
Dianbo Qu Ali Hage Katie Don-Carolis En Huang Alvin Joselin Farzaneh Safarpour Paul C. Marcogliese Maxime W. C. Rousseaux Sarah J. Hewitt Tianwen Huang Doo-Soon Im Steve Callaghan Danielle Dewar-Darch Daniel Figeys Ruth S. Slack David S. Park 《The Journal of biological chemistry》2015,290(51):30441-30452
Emerging evidence has demonstrated a growing genetic component in Parkinson disease (PD). For instance, loss-of-function mutations in PINK1 or PARKIN can cause autosomal recessive PD. Recently, PINK1 and PARKIN have been implicated in the same signaling pathway to regulate mitochondrial clearance through recruitment of PARKIN by stabilization of PINK1 on the outer membrane of depolarized mitochondria. The precise mechanisms that govern this process remain enigmatic. In this study, we identify Bcl2-associated athanogene 2 (BAG2) as a factor that promotes mitophagy. BAG2 inhibits PINK1 degradation by blocking the ubiquitination pathway. Stabilization of PINK1 by BAG2 triggers PARKIN-mediated mitophagy and protects neurons against 1-methyl-4-phenylpyridinium-induced oxidative stress in an in vitro cell model of PD. Collectively, our findings support the notion that BAG2 is an upstream regulator of the PINK1/PARKIN signaling pathway. 相似文献
993.
Young Im Choi Eun Woon Noh Hyo Shin Lee Mu Seok Han Jae Soon Lee Kwan Sam Choi 《Journal of Plant Biology》2007,50(6):658-662
Mercury is one of the most toxic metals to various organisms, including humans. Genes involved in mercury metabolism have been cloned fromStaphylococcus aureus, and were modified here to be expressed in plants. Transgenic poplars containing both chimeric genes (p35S-merA andp35S-merB) were developed via two rounds of transformation usingnos-nptll andnos-hpt genes as selectable markers. Although expression levels varied among transgenic lines, tolerance to either ionic mercury or organic mercury matched well with the degree of expression revealed by northern hybridization. In culture, these trees were tolerant to 50 μM HgCl2 and 2 μM CH3HgCI. Variations in mercury tolerance among the transgenic lines indicates that vigorous selection is required to select the best clones for use in phytoremediation. 相似文献
994.
In this study, the effects of phosphate concentration and carbon source on the patterns of alkaline phosphatase (APase) and phospholipase (PLase) expression in Vibrio vulnificus ATCC 29307 were assessed under various conditions. The activities of these enzymes were repressed by excess phosphate (4 mM) in the culture medium, but this repression was reversed upon the onset of phosphate starvation in low phosphate defined medium (LPDM) containing 0.2 mM of phosphate at approximately the end of the exponential growth phase. The expressions of the two enzymes were also influenced by different carbon sources, including glucose, fructose, maltose, glycerol, and sodium acetate at different levels. The APase activity was derepressed most profoundly in LPDM containing fructose as a sole carbon source. However, the repression/derepression of the enzyme by phosphate was not observed in media containing glycerol or sodium acetate. In LPDM-glycerol or sodium acetate, the growth rate was quite low. The highest levels of PLase activity were detected in LPDMsodium acetate, followed by LPDM-fructose. PLase was not fully repressed by high phosphate concentrations when sodium acetate was utilized as the sole carbon source. These results showed that multiple regulatory systems, including the phosphate regulon, may perform a function in the expression of both or either APase and PLC, in the broader context of the survival of V. vulnificus. 相似文献
995.
Specific interactions of serpins in their native forms attenuate their conformational transitions
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Plasminogen activator inhibitor-1 (PAI-1) belongs to the serine protease inhibitor (serpin) protein superfamily. Serpins are unique in that their native forms are not the most thermodynamically stable conformation; instead, a more stable, latent conformation exists. During the transition to the latent form, the first strand of beta-sheet C (s1C) in the serpin is peeled away from the beta-sheet, and the reactive center loop (RCL) is inserted into beta-sheet A, rendering the serpin inactive. To elucidate the contribution of specific interactions in the metastable native form to the latency transition, we examined the effect of mutations at the s1C of PAI-1, specifically in positions P4' through P10'. Several mutations strengthened the interactions between these residues and the core protein, and slowed the transition of the protein from the metastable native form to the latent form. In particular, anchoring of the strand to the protein's hydrophobic core at the beginning (P4' site) and center of the strand (P8' site) greatly retarded the latency transition. Mutations that weakened the interactions at the s1C region facilitated the conformational conversion of the protein to the latent form. PAI-1's overall structural stability was largely unchanged by the mutations, as evaluated by urea-induced equilibrium unfolding monitored via fluorescence emission. Therefore, the mutations likely exerted their effects by modulating the height of the energy barrier from the native to the latent form. Our results show that interactions found only in the metastable native form of serpins are important structural features that attenuate folding of the proteins into their latent forms. 相似文献
996.
Hoffman JR Im J Kang J Maresh CM Kraemer WJ French D Nioka S Kime R Rundell KW Ratamess NA Faigenbaum AD Chance B 《Journal of strength and conditioning research / National Strength & Conditioning Association》2007,21(1):118-122
The purpose of this study was to examine the effect of low- vs. high-intensity resistance exercise on lipid peroxidation. In addition, the role of muscle oxygenation on plasma malondialdehyde (MDA) concentrations was explored. Eleven experienced resistance trained male athletes (age: 20.8 +/- 1.3 years; weight: 96.2 +/- 14.4 kg; height: 182.4 +/- 7.3 cm) performed 4 sets of the squat exercise using either a low-intensity, high-volume (LI; 15 repetitions at 60% 1 repetition maximum [1RM]) or high-intensity, low-volume (HI; 4 repetitions at 90% 1RM load). Venous blood samples were obtained before the exercise (PRE), immediately following the exercise (IP), and 20 (20P) and 40 minutes (40P) postexercise. Continuous wave near-infrared spectroscopy was used to measure muscle deoxygenation in the vastus lateralis during exercise. Deoxygenated Hb/Mb change was used to determine reoxygenation rate during recovery. No difference in MDA concentrations was seen between LI and HI at any time. Significant correlations were observed between plasma MDA concentrations at IP and the half-time recovery (T1/2 recovery) of muscle reoxygenation (r = 0.45) and between T1/2 recovery and the area under the curve for MDA concentrations (r = 0.44). Results suggest that increases in MDA occur independently of exercise intensity, but tissue acidosis may have a larger influence on MDA formation. 相似文献
997.
Imène Ben Thabet Hamadi Attia Souhail Besbes Claude Deroanne Frédéric Francis Nour-Eddine Drira Christophe Blecker 《Food biophysics》2007,2(2-3):76-82
The present work aimed to study the physicochemical characteristics and the functional properties of the male date palm sap
(Phoenix dactylifera L.). The surface properties at the air–water interface were studied on the basis of the drop volume method. Foaming properties
(foam capacity and stability) were evaluated using bubbling method by optical and conductimetric measurements (foamscan).
Composition analysis revealed a high sugar content (92.29% w/w dry matter basis) with dominance of sucrose. Sap contains also 5.14% w/w of proteins and 2.57% w/w of ash. Proteins are probably the source of the surface activity and the observed foam power. At higher contents of dry matter,
lyophilized sap solutions showed Newtonian comportment and improved surface activity and foam properties. Results present
some interesting functional properties that suggest to deepen research particularly in sap proteins. 相似文献
998.
Kim SS Im HT Kang IM Lee HS Lee HW Cho SH Kim JB Lee KT 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2007,852(1-2):174-179
A sensitive and accurate HPLC-UV method for the quantification of fluconazole (FLA) level in human plasma has been developed. The sample was prepared by one-step liquid-liquid extraction (LLE) of FLA from plasma using dichloromethane. Phenacetin was used as the internal standard. The chromatographic retention times of FLA and phenacetin were 4.6 and 8.3 min, respectively. The lower limit of quantitation (LLOQ) was 0.05 microg/mL, and no interferences were detected in the chromatograms. The devised HPLC-UV method was validated by evaluating its intra- and inter-day precisions and accuracies in a linear concentration range between 0.05 and 10.00 microg/mL. The devised method was successfully applied to a bioequivalence studies involving the oral administration of a single 150 mg FLA tablet and 3 x 50 mg FLA capsules in healthy Korean male volunteers. 相似文献
999.
Pavel kaloud Magda kaloudov Pavla Dosko
ilov Jong Im Kim Woonghi Shin Petr Dvok 《Molecular ecology》2019,28(5):1084-1095
Although eukaryotic microorganisms are extremely numerous, diverse and essential to global ecosystem functioning, they are largely understudied by evolutionary biologists compared to multicellular macroscopic organisms. In particular, very little is known about the speciation mechanisms which may give rise to the diversity of microscopic eukaryotes. It was postulated that the enormous population sizes and ubiquitous distribution of these organisms could lead to a lack of population differentiation and therefore very low speciation rates. However, such assumptions have traditionally been based on morphospecies, which may not accurately reflect the true diversity, missing cryptic taxa. In this study, we aim to articulate the major diversification mechanisms leading to the contemporary molecular diversity by using a colonial freshwater flagellate, Synura sphagnicola, as an example. Phylogenetic analysis of five sequenced loci showed that S. sphagnicola differentiated into two morphologically distinct lineages approximately 15.4 million years ago, which further diverged into several evolutionarily recent haplotypes during the late Pleistocene. The most recent haplotypes are ecologically and biogeographically much more differentiated than the old lineages, presumably because of their persistent differentiation after the allopatric speciation events. Our study shows that in microbial eukaryotes, species diversification via the colonization of new geographical regions or ecological resources occurs much more readily than was previously thought. Consequently, divergence times of microorganisms in some lineages may be equivalent to the estimated times of speciation in plants and animals. 相似文献
1000.