Heavy nitrogen in the Yamato-74191 and the heterogeneity of the primitive solar nebula

A systematic search for presolar grains in ordinary chondrites was made by measuring isotopes of nitrogen. Only one chondrite (Yamato-74191) out of 20 ordinary chondrites showed the presence of very heavy nitrogen of probably presolar origin. The heavy nitrogen is not particularly concentrated in either magnetic nor non-magnetic fractions. The HF/HCl residue is enriched in nitrogen but the heavy nitrogen seems to have been lost by acid treatments. The carrier of the heavy nitrogen has not been identified. The release patterns of excess ^N are similar to those of primordial Ar. Chondrites more primitive than the Y-74191 do not contain the heavy nitrogen, suggesting heterogeneous distribution of the carrier of the heavy nitrogen. Together with evidence for the heterogeneous distribution of presolar SiC in meteorites, it is concluded that exotic materials were not well mixed in the primitive solar nebula

Airborne Bacterial Communities in Three East Asian Cities of China, South Korea, and Japan

The global diversity of airborne bacteria has not yet been studied, despite its importance in human health and climate change. Here, we focused on the diversity of airborne bacteria and their correlations with meteorological/environmental conditions in China, South Korea, and Japan. Beijing (China) had more diverse airborne bacteria, followed by Seoul (South Korea) and Nagasaki (Japan), and seasonal variations were observed. Beijing and Seoul had more diverse airborne bacteria during the winter, whereas Nagasaki showed greater diversity during the summer. According to principal component analysis and Bray-Curtis similarity, higher similarity was observed between Beijing and Seoul than between Seoul and Nagasaki during all seasons except summer. Among meteorological/environmental variables, temperature and humidity were highly correlated with the diversity of airborne bacteria on the measurement day, whereas wind speeds and the frequency of northwest winds were highly correlated for 2–3-day moving averages. Thus, proximity and resuspension could enhance bacterial diversity in East Asian cities

Airborne Bacterial Communities in Three East Asian Cities of China, South Korea, and Japan

The global diversity of airborne bacteria has not yet been studied, despite its importance in human health and climate change. Here, we focused on the diversity of airborne bacteria and their correlations with meteorological/environmental conditions in China, South Korea, and Japan. Beijing (China) had more diverse airborne bacteria, followed by Seoul (South Korea) and Nagasaki (Japan), and seasonal variations were observed. Beijing and Seoul had more diverse airborne bacteria during the winter, whereas Nagasaki showed greater diversity during the summer. According to principal component analysis and Bray-Curtis similarity, higher similarity was observed between Beijing and Seoul than between Seoul and Nagasaki during all seasons except summer. Among meteorological/environmental variables, temperature and humidity were highly correlated with the diversity of airborne bacteria on the measurement day, whereas wind speeds and the frequency of northwest winds were highly correlated for 2–3-day moving averages. Thus, proximity and resuspension could enhance bacterial diversity in East Asian cities

General palaeontology (Palaeobiochemistry) Biological activity and the Earth's surface evolution: Insights from carbon, sulfur, nitrogen and iron stable isotopes in the rock record

Abstract The search for early Earth biological activity is hindered by the scarcity of the rock record. The very few exposed sedimentary rocks have all been affected by secondary processes such as metamorphism and weathering, which might have distorted morphological microfossils and biogenic minerals beyond recognition and have altered organic matter to kerogen. The search for biological activity in such rocks therefore relies entirely on chemical, molecular or isotopic indicators. A powerful tool used for this purpose is the stable isotope signature of elements related to life (C, N, S, Fe). It provides key informations not only on the metabolic pathways operating at the time of the sediment deposition, but more globally on the biogeochemical cycling of these elements and thus on the Earth's surface evolution. Here, we review the basis of stable isotope biogeochemistry for these isotopic systems. Rather than an exhaustive approach, we address some examples to illustrate how they can be used as biosignatures of early life and as proxies for its environment, while keeping in mind what their limitations are. We then focus on the covariations among these isotopic systems during the Archean time period to show that they convey important information both on the evolution of the redox state of the terrestrial surface reservoirs and on co-occurring ecosystems in the Archean. Résumé Apport des isotopes stables (C, N, S, Fe) à l'étude des interrelations entre activités biologiques et conditions physicochimiques de surface de la terre primitive. La recherche et la caractérisation des écosystèmes à la surface de la Terre primitive sont un défi, étant donné le faible degré de préservation des roches archéennes. Les quelques formations sédimentaires disponibles ont, en effet, été modifiées par de nombreux processus secondaires (métamorphisme, altération) qui excluent toute diagnose morphologique robuste des microfossiles et des minéraux associés. La recherche de traces de vie fossile et la caractérisation des environnements contemporains du dépôt reposent ainsi sur des indices chimiques dont les plus robustes sont les isotopes stables. Dans ce manuscrit, nous tenterons de résumer les bases de la biogéochimie des isotopes stables et nous illustrerons comment cette discipline peut permettre d'apporter des contraintes sur la vie primitive et son environnement. Quelques exemples choisis dans différents systèmes isotopiques pertinents pour l'étude de la vie (C, N, S, Fe) et pour l'étude des conditions d'oxydation de surface de la Terre primitiv

General palaeontology (Palaeobiochemistry) Biological activity and the Earth's surface evolution: Insights from carbon, sulfur, nitrogen and iron stable isotopes in the rock record

Abstract The search for early Earth biological activity is hindered by the scarcity of the rock record. The very few exposed sedimentary rocks have all been affected by secondary processes such as metamorphism and weathering, which might have distorted morphological microfossils and biogenic minerals beyond recognition and have altered organic matter to kerogen. The search for biological activity in such rocks therefore relies entirely on chemical, molecular or isotopic indicators. A powerful tool used for this purpose is the stable isotope signature of elements related to life (C, N, S, Fe). It provides key informations not only on the metabolic pathways operating at the time of the sediment deposition, but more globally on the biogeochemical cycling of these elements and thus on the Earth's surface evolution. Here, we review the basis of stable isotope biogeochemistry for these isotopic systems. Rather than an exhaustive approach, we address some examples to illustrate how they can be used as biosignatures of early life and as proxies for its environment, while keeping in mind what their limitations are. We then focus on the covariations among these isotopic systems during the Archean time period to show that they convey important information both on the evolution of the redox state of the terrestrial surface reservoirs and on co-occurring ecosystems in the Archean. Résumé Apport des isotopes stables (C, N, S, Fe) à l'étude des interrelations entre activités biologiques et conditions physicochimiques de surface de la terre primitive. La recherche et la caractérisation des écosystèmes à la surface de la Terre primitive sont un défi, étant donné le faible degré de préservation des roches archéennes. Les quelques formations sédimentaires disponibles ont, en effet, été modifiées par de nombreux processus secondaires (métamorphisme, altération) qui excluent toute diagnose morphologique robuste des microfossiles et des minéraux associés. La recherche de traces de vie fossile et la caractérisation des environnements contemporains du dépôt reposent ainsi sur des indices chimiques dont les plus robustes sont les isotopes stables. Dans ce manuscrit, nous tenterons de résumer les bases de la biogéochimie des isotopes stables et nous illustrerons comment cette discipline peut permettre d'apporter des contraintes sur la vie primitive et son environnement. Quelques exemples choisis dans différents systèmes isotopiques pertinents pour l'étude de la vie (C, N, S, Fe) et pour l'étude des conditions d'oxydation de surface de la Terre primitiv

IL-6 secretion in osteoarthritis patients is mediated by chondrocyte-synovial fibroblast cross-talk and is enhanced by obesity

Increasing evidence suggests that inflammation plays a central role in driving joint pathology in certain patients with osteoarthritis (OA). Since many patients with OA are obese and increased adiposity is associated with chronic inflammation, we investigated whether obese patients with hip OA exhibited differential pro-inflammatory cytokine signalling and peripheral and local lymphocyte populations, compared to normal weight hip OA patients. No differences in either peripheral blood or local lymphocyte populations were found between obese and normal-weight hip OA patients. However, synovial fibroblasts from obese OA patients were found to secrete greater amounts of the pro-inflammatory cytokine IL-6, compared to those from normal-weight patients (p < 0.05), which reflected the greater levels of IL-6 detected in the synovial fluid of the obese OA patients. Investigation into the inflammatory mechanism demonstrated that IL-6 secretion from synovial fibroblasts was induced by chondrocyte-derived IL-6. Furthermore, this IL-6 inflammatory response, mediated by chondrocyte-synovial fibroblast cross-talk, was enhanced by the obesity-related adipokine leptin. This study suggests that obesity enhances the cross-talk between chondrocytes and synovial fibroblasts via raised levels of the pro-inflammatory adipokine leptin, leading to greater production of IL-6 in OA patients

7th Drug hypersensitivity meeting: part two

No abstract availabl