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21.
Johanna Marin‐Carbonne Vincent Busigny Jennyfer Miot Claire Rollion‐Bard Elodie Muller Nadja Drabon Damien Jacob Sylvain Pont Martin Robyr Tomaso R. R. Bontognali Camille Franois Stephanie Reynaud Mark Van Zuilen Pascal Philippot 《Geobiology》2020,18(3):306-325
On the basis of phylogenetic studies and laboratory cultures, it has been proposed that the ability of microbes to metabolize iron has emerged prior to the Archaea/Bacteria split. However, no unambiguous geochemical data supporting this claim have been put forward in rocks older than 2.7–2.5 giga years (Gyr). In the present work, we report in situ Fe and S isotope composition of pyrite from 3.28‐ to 3.26‐Gyr‐old cherts from the upper Mendon Formation, South Africa. We identified three populations of microscopic pyrites showing a wide range of Fe isotope compositions, which cluster around two δ56Fe values of ?1.8‰ and +1‰. These three pyrite groups can also be distinguished based on the pyrite crystallinity and the S isotope mass‐independent signatures. One pyrite group displays poorly crystallized pyrite minerals with positive Δ33S values > +3‰, while the other groups display more variable and closer to 0‰ Δ33S values with recrystallized pyrite rims. It is worth to note that all the pyrite groups display positive Δ33S values in the pyrite core and similar trace element compositions. We therefore suggest that two of the pyrite groups have experienced late fluid circulations that have led to partial recrystallization and dilution of S isotope mass‐independent signature but not modification of the Fe isotope record. Considering the mineralogy and geochemistry of the pyrites and associated organic material, we conclude that this iron isotope systematic derives from microbial respiration of iron oxides during early diagenesis. Our data extend the geological record of dissimilatory iron reduction (DIR) back more than 560 million years (Myr) and confirm that micro‐organisms closely related to the last common ancestor had the ability to reduce Fe(III). 相似文献
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Carrière Audrey Lagarde Damien Jeanson Yannick Portais Jean-Charles Galinier Anne Ader Isabelle Casteilla Louis 《Journal of physiology and biochemistry》2020,76(2):241-250
Journal of Physiology and Biochemistry - Thermogenic (brown and beige) adipose tissues improve glucose and lipid homeostasis and therefore represent putative targets to cure obesity and related... 相似文献
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Monica L. Bond Barbara König Arpat Ozgul Damien R. Farine Derek E. Lee 《The Journal of wildlife management》2021,85(5):920-931
Populations are typically defined as spatially contiguous sets of individuals, but large populations of social species can be composed of discrete social communities that often overlap in space. Masai giraffes (Giraffa camelopardalis tippelskirchi) of Tanzania live in distinct social subpopulations that overlap spatially, enabling us to simultaneously explore environmental and social factors correlated with demographic variation in a metapopulation of >1,400 adult females and calves. We considered statistically distinct communities in the social network as subpopulations and tested for variation among the 10 subpopulations in adult female survival, calf survival, and reproductive rate (calf-to-adult female ratio). We then related variation in demographic rates among subpopulations to differences in vegetation, soil type, proximity to 2 types of human settlements, local giraffe population density, and social metrics of relationship strength and exclusivity among adult females. We did not find any among-subpopulation effects on adult female survival, suggesting adult female survival is buffered against environmental heterogeneity among subpopulations. Variation in calf demographic rates among subpopulations were correlated with vegetation, soils, anthropogenic factors, and giraffe population density but not with adult female relationship metrics, despite substantial spatial overlap. Subpopulations with more dense bushlands in their ranges had lower calf survival probabilities, and those closer to human settlements had higher reproductive rates, possibly because of spatial gradients in natural predation. Reproductive rates were higher in subpopulations with more volcanic soils, and calf survival probabilities were greater in subpopulations with higher local adult female densities, possibly related to higher-quality habitat associated with fertile soils or lower predation risk, or to greater competitive ability. The variation in fitness among subpopulations suggests that giraffes do not move unhindered among resource patches to equalize reproductive success, as expected according to an ideal free distribution. The differences in calf survival and reproductive rates could rather indicate intercommunity differences in competitive ability, perception, learning, or experience. Our approach of comparing demography among spatially overlapping yet distinct socially defined subpopulations provides a biologically meaningful way to quantify environmental and social factors influencing fine-scale demographic variation for social species. © 2021 The Wildlife Society. 相似文献
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Damien Garbett Cécile Sauvanet Raghuvir Viswanatha Anthony Bretscher 《Molecular biology of the cell》2013,24(21):3381-3392
The closely related apical scaffolding proteins ERM-binding phosphoprotein of 50 kDa (EBP50) and NHE3 kinase A regulatory protein (E3KARP) both consist of two postsynaptic density 95/disks large/zona occludens-1 (PDZ) domains and a tail ending in an ezrin-binding domain. Scaffolding proteins are thought to provide stable linkages between components of multiprotein complexes, yet in several types of epithelial cells, EBP50, but not E3KARP, shows rapid exchange from microvilli compared with its binding partners. The difference in dynamics is determined by the proteins’ tail regions. Exchange rates of EBP50 and E3KARP correlated strongly with their abilities to precipitate ezrin in vivo. The EBP50 tail alone is highly dynamic, but in the context of the full-length protein, the dynamics is lost when the PDZ domains are unable to bind ligand. Proteomic analysis of the effects of EBP50 dynamics on binding-partner preferences identified a novel PDZ1 binding partner, the I-BAR protein insulin receptor substrate p53 (IRSp53). Additionally, the tails promote different microvillar localizations for EBP50 and E3KARP, which localized along the full length and to the base of microvilli, respectively. Thus the tails define the localization and dynamics of these scaffolding proteins, and the high dynamics of EBP50 is regulated by the occupancy of its PDZ domains. 相似文献
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Marie-Annette Carbonneau Emeline Cartron Claude-Louis Leger Christiane Senglat Bernard Descomps 《Free radical research》2013,47(2):127-142
Oxidized low density lipoprotein (LDL) plays an important role in atherogenesis. It is generally thought that LDL is mainly oxidized in the intima of vessel walls, surrounded by hydrophilic antioxidants and proteins such as albumin. The aim of this study was to investigate the possible interrelationships between oxidation resistance of LDL and its protein and lipid moieties. Proteins and to a lesser extent lipids, appeared to be the major determinants in the LDL Cu 2+ -oxidation resistance, which in turn depend on the ultracentrifugation (UC) procedure used. Comparing high speed/short time (HS/ST, 4 u h), high speed/long time (HS/LT, 6-16 u h) and low speed/long time (LS/LT, 24 u h) conditions of UC, HS with the shortest time (4 u h) led to prepare LDL (named LDL·HS-4 u h) with higher total protein and triglyceride contents, unchanged total cholesterol, phospholipids and Vitamin E, and higher Cu 2+ -oxidation resistance. Among proteins, only albumin allows to explain changes. PAF acetyl hydrolase appeared to be unaffected, whereas its pro-oxidant role was established and found only in the absence of albumin. In contrast the pro-oxidant role of caeruloplasmin took place regardless of the albumin content of LDL. The antioxidant effect of albumin (the oxidation lag time was doubled for 20 u mol/mol albumin per LDL) is assumed to be due to its capacity at decreasing LDL affinity for Cu 2+ . Interestingly, the LDL·HS-4 u h albumin content mirrored the intrinsic characteristics of LDL in the plasma and was not affected by added free albumin. Moreover, it has been verified that in 121 healthy subjects albumin was the best resistance predictor of the Cu 2+ -oxidation of LDL·HS-4 u h, with a multiple regression equation: lag time (min)=62.1+0.67(HSA/apoB)+0.02 (TG/apoB) m 0.01(TC/apoB); r =0.54, P <0.0001. Accounted for by lag time, the oxidation resistance did not correlate with f -tocopherol and ubiquinol contents of LDL. The mean albumin content was about 10 u mol/mol, and highly variable (0-58 u mol/mol) with subjects. The LDL·HS-4 u h may account for the status of LDL in its natural environment more adequately than LDL resulting from other conditions of UC. 相似文献
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The current study investigated the accident rates across morning, late, and night shifts in rotating shift-workers employed in two different shift rotations at the same steel work factory. A retrospective analysis has been performed of accident data (N = 578) over a 5-year period (2003 through 2007) of 730 male shift-workers employed in either a clockwise (mean age of the workers 38.1 ± SD 9.8 years) or counterclockwise rotation (mean age 38.0 ± SD 10.1 years) with comparable work conditions. The overall accident rate across the 24-h day was not significantly different between clockwise and counterclockwise shift rotation. In both shift-work rotations, morning shifts as opposed to night shifts exhibited a significantly higher accident rate. There was no significant difference between late shifts and morning or night shifts in either shift rotation. The increased accident rate in the morning shift at this steel factory could be related to the early starting time of the shift and to this shift being more labor intensive in both shift rotations. These findings suggest that work-related factors must be considered in addition to shift-work schedules when investigating accident rates in rotating shift-workers. 相似文献
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Jean Guillon Maria Mamani-Matsuda Stephane Massip Jean-Michel Leger Denis Thiolat Djavad Mossalayi 《Journal of enzyme inhibition and medicinal chemistry》2013,28(6):391-396
The synthesis of new 7-hydroxy-2-substituted-methyl-5 H -oxazolo[3,2- a] pyrimidin-5-ones derivatives, designed as structural bicyclic analogues of the iron chelator deferiprone, is described. They were tested for their ability to inhibit proliferation in human Bcr-Abl + leukemia cells. 相似文献