Relating changes of organic matter composition of two German peats to climatic conditions during peat formation

Congreso celebrado del 2-7 mayo 2010, en Viena, Austria.Peatlands have been recognized as an important factor within the global C-cycle, since they store about one-third of the global terrestrial C-pool. Furthermore, peat deposits have the potential to record detailed paleoclimatic and – vegetational changes. They are formed in peculiar paleoecosystems where the slow biodegradation of plant residues depends on a series of pedo-climatic and hydromorphic factors leading to a progressive accumulation of organic matter stabilized in different evolutionary stages. Thus, its chemical composition should be applicable as a fingerprint of former prevailing environmental conditions and vegetation configurations. The aim of the present work was to identify this fingerprint in the cores of two German fens, one derived from the Havelland close to Berlin (Großer Bolchow) and the other derived from the alpine region of Bavaria (Kendlmühlfilzen) by investigating the organic matter transformation as a function of peat depths.Peer reviewe

IMMUNE RESPONSE TO SARS-COV-2 IN PATIENTS WITH CHRONIC HIV INFECTION

Introduction. Data for the long-term effects of SARS-CoV-2/HIV co-infection on immune restoration, as well as the level of post-exposure and post-vaccination immunity at the current stage of SARS-CoV-2 pandemic in HIV+ individuals is still scarce. We assessed SARS-CoV-2-specific immune responses, and the effects of SARS-CoV-2 infection on the immune recovery in HIV+cART+ patients with different exposure history.  Materials and methods. HIV+cART+ patients 9 (2-18) months after mild/moderate COVID-19 and completed immunization with anti-SARS-CoV-2 vaccine (n=13, group A), convalescent, not immunized (n=11, group B), or with no history of exposure to SARS-CoV-2 (n=11, group C) were included in the study. CD4AC and CD4/CD8 ratio were determined before and after the documented/probable contact with SARS-CoV-2 by 4-color flow cytometry (TRUCount, MultiTest, FACSCanto II). Virus-specific immunity was characterized by the SARS-CoV-2 specific IFNγ production (SARS-CoV-2 IGRA, Euroimmun) and the levels of RBD-IgG ((Euroimmun ELISA).  Results. SARS-CoV-2 specific T-cell and IgG responses were highly correlated and present, respectively, in 92% and 100%; 64% and 54%, 36% and 50% from group A, B and C patients. SARS-CoV-2 specific IFNy+T cells and RDB-IgG were significantly higher in the group with hybrid exposure (A) as compared to convalescent (B) and asymptomatic (C) patients. No significant difference existed between background and actual CD4AC (mean 836 vs 799 cells/µl, p>0.05, Mann-Whitney), and the CD4/CD8 ratio significantly increased in the group with hybrid exposure (0.92 vs 1.07, p<0.01, paired T-test).  Conclusion. Over 80% of tested HIV+ individuals have mounted a SARS-CoV-2 specific immune response. Immunization and hybrid exposure provide a durable and significantly stronger SARS-CoV-2-specific immune response as compared to mild/ asymptomatic infection, without affecting the long-term immune recovery

FERROPTOSIS IN CD4+ AND CD8+ T-CELLS IN THE SETTINGS OF HIV INFECTION

Introduction: Elevation of intracellular iron concentration triggers ferroptosis. Understanding the regulation and pathophysiological mechanisms of this process in HIV infection may contribute to antiretroviral therapy (cART) monitoring. Aim: To perform a correlation analysis of the intracellular labile-bound iron pool (LIP) in CD4+ and CD8+ T cells in association with CD4+, CD8+ T cells absolute count (AC) and CD4/CD8 index in HIV+ individuals on continuous cART with sustained viral suppression. Material and methods: Peripheral blood samples (Li heparin, n=34) were collected in the course of the routine immune monitoring of HIV+ individuals at four time points during 24 months. Plasma HIV viral load (VL) was determined with the Abbott Real-Time HIV-1 test (sensitivity 40 copies/ml). AC and percentage of CD4+ and CD8+ T cells were determined by direct flow cytometry (Multitest, BD Trucount, FACS Canto II). The intracellular content of LIP in CD4 and CD8 T cells (LIP CD4, LIP CD8) was measured at the beginning of the study, using acetoxymethyl ester and subsequent incubation with a chelator (Deferiprone). LIP was quantified according to the mean fluorescence intensity (MFI) (FACSCanto II, Diva 6.1.2). Results: In the settings of a higher LIP CD4 , high LIP CD8 correlated with increased CD8AC (Rho=0.70, p<0.05) up to 11 (min. 6, max. 15) months after LIP measurement., and decreased CD4/CD8 ratio correlated inversely with LIP CD8 in all consecutive measurements (Rho= -0.71, p<0.01 for all), Importantly, high LIP CD8 correlated with a lower CD4AC (Rho=-0.65, p<0.05) up to five (min.1, max.8) months after LIP measurement. Conclusion: The increased concentration of intracellular LIP in CD8 cells in HIV+cART individuals could indicate viral activity in the settings of undetectable HIV VL, directly associated with ongoing cell ferroptosis

Essais en Théorie des Organisations : Incitations et Structure des Organisations

This thesis treats three subjects of theory of organizations. At first, we study the impact of changes in the institutional environment and characteristics of the labor market on the structure of organizations, and how these evolutions in turn allocate the employment and the salaries. This is made within the framework of a model of balance on the labor market, where the structure of organizations is endogenous and the production is organized in hierarchies based on knowledge. Then, we study the shape of the optimal incentive contract when the employees are heterogeneous and their performance is not verifiable. We show that the employer can motivate the agents by using simultaneously a fixed salary with the threat of redundancy in case of failure and a bonus based on the performance. The relative part of each of these two tools in the optimal contract depends on the heterogeneousness of the employees, on their hoped productivity, but also on the rate of belchCette thèse traite trois sujets de théorie des organisations. D'abord, nous étudions l'impact de changements dans l'environnement institutionnel et des caractéristiques du marché du travail sur la structure des organisations, et comment ces évolutions à leur tour affectent l'emploi et les salaires. Ceci est effectué dans le cadre d'un modèle d'équilibre sur le marché du travail, où la structure des organisations est endogène et la production est organisée dans des hiérarchies basées sur les connaissance. Ensuite, nous étudions la forme du contrat incitatif optimal lorsque les employés sont hétérogènes et leur performance n'est pas vérifiable. Nous montrons que l'employeur peut motiver les agents en utilisant simultanément un salaire fixe avec la menace de licenciement en cas d'échec et un bonus basé sur la performance. La part relative de chacun de ces deux outils dans le contrat optimal dépend de l'hétérogénéité des employés, de leur productivité espérée, mais également du taux de rotation exogène et du taux de chômage. Enfin, nous examinons l'impact de la possibilité pour les employés de se superviser mutuellement sur le contrat optimal proposé par l'employeur. Nous montrons que lorsque les employés sont suffisamment bien informés et peu protégés par la responsabilité limitée, cette possibilité de supervision mutuelle permet de réduire le coût des incitations, encouru par l'employeu

Mutual Monitoring versus Incentive Pay in Teams

In a principal - multi-agent relationship, we derive the optimal mutualmonitoring - incentive pay mix. When the agents are better informed about theireffort choices than the principal, and when their information is sufficiently"good" there is a substituability between those two modes of providingincentives. However we show that the optimal mix depends on agents' liabilitylimit. When it is sufficiently slack the principal uses stronger incentive pay andless mutual monitoring. We also derive the conditions for adoption of costlymutual monitoring technology.

Alteration of quality and stability of organic matter in grassland soils of Southern Brazil highlands after ceasing biannual burning

The impact of ceasing biannual burning on quality and quantity of soil organic matter (SOM) in grassland soils from Southern Brazil was studied by means of solid-state 13C and 15N NMR spectroscopy using soil duplicates of fields without 1, 2, 5 and 22 years of burning. The examination of the duplicates demonstrated good reproducibility. Demineralization of the soil with hydrofluoric acid (HF) indicated that the fire frequency had no impact on the amount of HF-extractable SOM. Exclusion of fire resulted in a considerable decrease of the organic C-stocks, whereas N and S stocks were only slightly affected. Determination of the content of pyrogenic organic C (PyOC) via combination of the methods of chemical oxidation with acid dichromate and solid-state 13C NMR spectroscopy of the oxidation resistant fraction revealed that this decline was caused by the reduced input of decaying plant roots remaining in the soil after combustion of the aboveground vegetation during a fire. In spite of frequent burning for centuries, the PyOC concentrations were unexpectedly low in the top 5 cm of the studied soils but increased clearly with soil depth, which indicated that some charcoal constituents can be translocated with the soil solution. With respect to the stability of charcoal in the grassland soils, our study revealed that comparable to SOM, PyOM is composed of fractions with different stability against microbial degradation. Whereas the labile PyOM fraction showed C-losses similar to that of O-alkyl C, the more stable PyOM fraction was selectively preserved together with an alkyl fraction. Based on the results of the present study, one can conclude that frequent burning of grassland can lead to an increased C-sequestration potential of a soil. Because the input of the additional C is mainly caused by a higher biomass production after the fire, the additional SOM contributes to the labile pool with short turn-over times rather than to the recalcitrant carbon fraction. After ceasing burning, the reduced litter input cannot compensate the fast consumption of this pool and a quick decrease of the C stocks is expected.Peer Reviewe

Expression of membrane-bound β-Klotho on peripheral blood CD4+ and CD8+ T lymphocytes of healthy subjects

AbstractImmunosenescence is driven by repeated and continuous immune activation. Sensitive markers are warranted to detect and monitor the process of premature immune ageing. We analysed the β-Klotho expression on T-cell subsets from healthy donors: young adults, n = 12 (20–30 y); middle-aged, n = 62 (30–50 y) and elderly, n = 18 (>70 y). The absolute counts (AC) and percentages of total, CD4+, CD8+ and CD8 + CD27-CD57+ T-cells, CD4/CD8 ratio, and the share of β-Klotho + T-cell subsets were analysed by multicolour flow cytometry. AC of T-cell subsets showed non-significant differences among the groups. The percentages of β-Klotho(+) total, CD4+ and CD8+ T-cells in young adults exceeded significantly the expression in the elderly and middle-aged subjects: (mean) 2.13 vs. 0.48; 3.23 vs. 0.48; 6.87 vs. 2.28, and 0.75 vs. 2.21; 0.93 vs. 3.32; 6.62 vs. 6.62, respectively (p < 0.05 all). The β-Klotho expression on total, CD4+ and CD8+ T-cells among middle-aged participants was heterogeneous and significantly higher from the elderly only in CD8 + T-cells (mean): 0.75 vs. 0.47 (p = 0.1); 0.93 vs. 0.72 (p = 1.0) and 3.62 vs 1.75 (p = 0.01), respectively. The proportion of β-Klotho(+) CD8+ cells did not correlate with age, but correlated inversely and significantly with the share of CD27-CD57 + CD8+ T-cells in middle-aged subjects (R = −0.4, p < 0.01). We hypothesise that CD8 + T-cells showed higher sensitivity to the effects of immune-senescence, at least in part, due to the higher expression and dependence on the effects of KLOTHO gene products. We propose that a reduced share of β-Klotho + CD8+ T-cells indicates exhaustion due to immune activation, and may serve as an early marker of premature immunosenescence

Eicosanoid and cytokine levels differentiate between stages of MTB infection

Abstract Introduction: The need for biomarkers predicting the course of MTB infection and the necessity of specific therapy are well recognized. Recent data point to the role of cytokines and lipid mediators in protective immunity against tuberculosis. Aim: We evaluated the balance between cytokines, and eikosanoids as a possible prognostic indicator in MTB infection. Material and methods: The induced expression of effector and regulatory cytokines IFN-γ, TNF-α, IL-2, IL-17, IL-6, and IL-10 was measured in relation to the lipid mediators PGE2 and LXA4 in active TB infection (ATB, n=15) before and after therapy (ATB-T, n=6), established latent infection (LTBI, n=22), recent contacts of ATB (RC, n=12), and healthy controls (n=11) A flow cytometry microarray (CBA, BD Biosciences) and quantitative ELISA (SunRed Tech) were employed. Results: The regulatory cytokines (RC) were characterized by a high potential for IL-17 and Th1 cytokine secretion, combined with low IL-6 expression, while ATB donors had a partially preserved TNF-α potential, and higher IL-6 expression. The PGE2-to-LXA4 ratio discriminated between situations with high bacterial load (ATB), and contained infection (LTBI, ATB-T), and defined clearly cut subgroups among RC and ATB donors. Conclusions: Our results suggest that increased PGE2/LXA4 ratio coupled with high induced IL-10 level indicates infection after a recent contact. In the settings of ATB, increased ratio and low TNF-α level point to inefficient granuloma formation in the settings of ATB

Screening of pharmacogenetic variants associated with drug sensitivity in patients with papillary thyroid carcinoma using next generation sequencing

Thyroid cancer is the most common malignant tumour of the endocrine system. One of the most frequent types of thyroid malignancy is papillary carcinoma. In our study, we performed next generation sequencing (NGS) using a cancer panel (Illumina; Illumina, San Diego, USA) to screen for pharmacogenetic susceptibility variants in blood samples of 10 patients with papillary thyroid cancer (PTC). We report variants rs1042522 (TP53), rs2228001 (XPC), rs2227983 (EGFR), rs13181 (ERCC2), rs17655 (ERCC5) and rs1799939 (RET), which were detected in the analyzed patients either in homozygous and/or heterozygous state previously known to be connected with pharmacogenetic sensitivity to certain drugs in oncology. The results showed the TruSight Cancer Panel to be a useful clinical tool for determination of oncotherapy-associated pharmacogenetic variants in the blood of patients