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Non-growing season CO₂ emissions from Arctic tundra remain a major uncertainty in forecasting climate change consequences of permafrost thaw. We present the first time series of soil and microbial CO₂ emissions from a graminoid tundra based on year-round in situ measurements of the radiocarbon content of soil CO₂ (Δ¹⁴CO₂) and of bulk soil C (Δ¹⁴C), microbial activity, and temperature. Combining these data with land-atmosphere CO₂ exchange allows estimates of the proportion and mean age of microbial CO₂ emissions year-round. We observe a seasonal shift in emission sources from fresh carbon during the growing season (August Δ¹⁴CO₂ = 74 ± 4.7‰, 37% ± 3.4% microbial, mean ± se) to increasingly older soil carbon in fall and winter (March Δ¹⁴CO₂ = 22 ± 1.3‰, 47% ± 8% microbial). Thus, rising soil temperatures and emissions during fall and winter are depleting aged soil carbon pools in the active layer and thawing permafrost and further accelerating climate change.

Educational inequalities in mortality have been observed for decades, however the underlying biological mechanisms are not well known. We assessed the mediating role of altered aging of immune cells functioning captured by DNA methylation changes in blood (known as epigenetic clocks) in educational associated all-cause mortality. Data were from eight prospective population-based cohort studies, representing 13,021 participants. We found educational inequalities in mortality were larger for men than for women, estimated by hazard differences and ratios. Epigenetic clocks explained approximately 50% of educational inequalities in mortality for men, while the proportion was small for women. Most of this mediation was explained by differential effects of unhealthy lifestyles and morbidities of the WHO risk factors for premature mortality. These results support DNA methylation-based epigenetic aging as a signature of educational inequalities in life expectancy emphasizing the need for policies to address the unequal social distribution of these WHO risk factors.

We developed a passive sampler for time-integrated collection and radiocarbon (¹⁴C) analysis of soil respiration, a major flux in the global C cycle. It consists of a permanent access well that controls the CO₂ uptake rate and an exchangeable molecular sieve CO₂ trap. We tested how access well dimensions and environmental conditions affect collected CO₂, and optimized cleaning procedures to minimize ¹⁴CO₂ memory. We also deployed two generations of the sampler in Arctic tundra for up to two years, collecting CO₂ over periods of 3 days–2 months, while monitoring soil temperature, volumetric water content, and CO₂ concentration. The sampler collects CO₂ at a rate proportional to the length of a silicone tubing inlet (7–26 µg CO₂-C day⁻¹·m Si⁻¹). With constant sampler dimensions in the field, CO₂ recovery is best explained by soil temperature. We retrieved 0.1–5.3 mg C from the 1st and 0.6–13 mg C from the 2nd generation samplers, equivalent to uptake rates of 2–215 (n=17) and 10–247 µg CO₂-C day⁻¹ (n=20), respectively. The method blank is 8 ± 6 µg C (mean ± sd, n=8), with a radiocarbon content (fraction modern) ranging from 0.5875–0.6013 (n=2). The sampler enables more continuous investigations of soil C emission sources and is suitable for Arctic environments.

Background: Chronic diseases like diabetes mellitus or hypertension are a major public health challenge. Irregular physical activity (PA) is one of the most important modifiable risk factors for chronic conditions and their complications. However, engaging in regular PA is a challenge for many individuals. The literature suggests that a diagnosis of a disease might serve as a promising point in time to change health behavior. This study investigates whether a diagnosis of diabetes or hypertension is associated with changes in PA. Methods: Analyses are based on 4261 participants of the population-based KORA S4 study (1999&ndash, 2001) and its subsequent 7-and 14-year follow-ups. Information on PA and incident diagnoses of diabetes or hypertension was assessed via standardized interviews. Change in PA was regressed upon diagnosis with diabetes or hypertension, using logistic regression models. Models were stratified into active and inactive individuals at baseline to avoid ceiling and floor effects or regression to the mean. Results: Active participants at baseline showed higher odds (OR = 2.16 [1.20, 3.89]) for becoming inactive after a diabetes diagnosis than those without a diabetes diagnosis. No other significant association was observed. Discussion: As PA is important for the management of diabetes or hypertension, ways to increase or maintain PA levels in newly-diagnosed patients are important. Communication strategies might be crucial, and practitioners and health insurance companies could play a key role in raising awareness.

Monosomy of chromosome 17 may affect the assessment of HER2 amplification. Notably, the prevalence ranges from 1% up to 49% due to lack of consensus in recognition. We sought to investigate the impact of monosomy of chromosome 17 to interpretation of HER2 gene status. 201 breast carcinoma were reviewed for HER2 gene amplification and chromosome 17 status. FISH analysis was performed by using double probes (LSI/CEP). Absolute gene copy number was also scored per each probe. HER2 FISH test was repeated on serial tissue sections, ranging in thickness from 3 to 20 µm. Ratio was scored and subsequently corrected by monosomy after gold control test using the aCGH method to overcome false interpretation due to artefactual nuclear truncation. HER2 immunotests was performed on all cases. 26/201 cases were amplified (13%). Single signals per CEP17 were revealed in 7/201 (3.5%) cases. Five out of 7 cases appeared monosomic with aCGH (overall, 5/201, 2.5%) and evidenced single signals in >60% of nuclei after second-look on FISH when matching both techniques. Among 5, one case showed amplification with a pattern 7/1 (HER2/CEP17>2) of copies (3+ at immunotest); three cases revealed single signals per both probes (LSI/CEP=1) and one case revealed a 3:1 ratio; all last 4 cases showed 0/1+ immunoscore. We concluded that: 1) monosomy of chromosome 17 may be observed in 2.5% of breast carcinoma; 2) monosomy of chromosome 17 due to biological reasons rather than nuclear truncation was observed when using the cut-off of 60% of nuclei harboring single signals; 3) the skewing of the ratio due to single centromeric 17 probe may lead to false positive evaluation; 4) breast carcinomas showing a 3:1 ratio (HER2/CEP17) usually show negative 0/1+ immunoscore and

Since target therapy with mTOR inhibitors plays an important role in the current management of clear cell renal cell carcinoma (RCC), there is an increasing demand for predictive biomarkers, which may help to select patients that are most likely to benefit from personalized treatment. When dealing with formalin-fixed paraffin-embedded (FFPE) cancer tissue specimens, several techniques may be used to identify potential molecular markers, yielding different outcome in terms of accuracy. We sought to investigate and compare the capability of three main techniques to detect molecules performing an active function in mTOR pathway in RCC. Immunohistochemistry (IHC), Western blot (WB) and immunofluorescence (IF) analyses were performed on FFPE RCC tissue specimens from 16 patients by using the following mTOR pathway-related: mTOR (Ser235/236), phospho-mTOR (p-mTOR/Ser2448), phospho-p70S6k (p-p70S6k/Thr389), both monoclonal and polyclonal, phospho-S6Rb (p-S6Rb) and phospho-4EBP1 (p-4EBP1/Thr37/46). No single molecule was simultaneously revealed by all three techniques. Only p-p70S6k was detected by two methods (IHC and IF) using a monoclonal antibody. The other molecules were detected exclusively by one technique, as follows: p-mTOR and polyclonal p-p70S6K by IHC, p70S6K, p-S6Rb and p-4EBP1 by WB, and, finally, mTOR by IF. We found significant differences in detecting mTOR pathway-related active biomarkers by using three common techniques such as IHC, WB and IF on RCC samples. Such results have important implications in terms of predictive biomarker testing, and need to be related to clinical end-points such as responsiveness to targeted drugs by prospective studies.

p63, a member of the p53 family, is involved in the survival and differentiation of reserve/stem cells in different epithelia. To unveil the possible role of p63 in thymic physiology and pathology, we investigated the expression of p63 isoforms in normal thymus, thymomas and other mediastinal tumours. All samples were analysed using immunohistochemistry with three different antibodies: 4A4 antibody recognising all p63 isoforms, p40 antibody reacting only with truncated dominant-negative isoforms (DeltaN-p63) and H-129 antibody recognising all alpha-isoforms. Reverse-transcription polymerase chain reaction (RT-PCR), and real-time PCR analyses were performed on RNA extracted from frozen samples of four thymomas and two primary-mediastinal large-B-cell lymphoma (PMLBCL). In normal thymus, DeltaN-p63alpha was expressed in all cortical and medullary epithelial cells, with decreasing intensity in Hassall's corpuscles. This phenotype was conserved in neoplastic transformation since all 54 investigated thymomas (World Health Organization types A, AB, B1, B2, B3, C) expressed DeltaN-p63alpha (virtually 100% cells). The predominance of DeltaN-p63alpha isoform mRNA was confirmed by real-time PCR. Among other mediastinal tumours, DeltaN-p63alpha was only expressed in those displaying either a stratified epithelial component (teratomas) or epidermoid differentiation (lung carcinoma). Among lymphomas, T-cell-precursor lymphomas did not express p63, whereas most PMLBCL expressed TA-p63alpha (7/8). OI Scarpa, Aldo/0000-0003-1678-739X ZR 0 ZS 0 ZB 23 Z8 3

International audience

International audience; Test of different hypothesis on size structure predictors on a dataset including 726 European lakes. Size structure of fish assemblages in European lowland lakes are relatively robust against environmental modifications. Fish assemblages in high-altitude coldwater lakes may suffer dramatic consequences from global warming because species shifts may be accompanied by substantial shifts in size structure.

Les systèmes d'évaluation des masses d'eau doivent être intercalibrés afin de s'assurer de leur harmonisation entre pays partageant les mêmes types de milieux. La France est impliquée dans 3 groupes régionaux d'inter-étalonnage (GIG Alpin, Méditerranéen et Central Baltique) et coordonne le groupe transversal travaillant sur l'ichtyofaune.

Hypersensitivity Pneumonitis (HP) is an interstitial lung disease that occurs upon exposure to a variety of inhaled organic antigens. The presence of small non-caseating granulomas and isolated giant cells is not specific, but is considered a relevant histological feature for HP. The detection of granulomas is widely considered as easy on standard histological stains, but microgranuloma detection can be difficult and/or time consuming, especially in chronic HP cases. Cathepsin K (Cath-K) is a potent cysteine protease expressed at high levels in activated macrophages (osteoclasts, and epithelioid cells in granulomas), but is not expressed in resident macrophages thus representing a promising marker to rapidly detect and quantitatively evaluate microgranulomas in interstitial lung diseases. We analyzed the expression of Cath-K by immunohistochemistry in 22 subacute and chronic HP cases, using semi-quantitative scores. Control samples included normal lung tissue, and a variety of interstitial lung diseases: 3 Wegener's granulomatosis, 3 sarcoidosis, 3 tuberculosis, 1 berylliosis, 20 idiopathic pulmonary fibrosis (IPF), 2 Langerhans' cell histiocytosis, 5 nonspecific-interstitial pneumonia (NSIP), 5 cryptogenic organising-pneumonia (COP), 2 Airway-Centered Interstitial Fibrosis (ACIF), 5 desquamative interstitial pneumonia (DIP), 3 respiratory bronchiolitis interstitial lung disease (RB-ILD). Intense expression of Cath-K was demonstrated in epithelioid and giant cells in all cases containing granulomas (HP, sarcoidosis, Wegener's granulomatosis, berylliosis, tuberculosis). Among HP cases 19/22 (86.3%) contained granulomas that could be semiquantitatively evaluated. In all HP and control cases alveolar macrophages did not express Cath-K, including cases characterised by large collections of alveolar macrophages such as DIP and RB-ILD.Cath-K represents a sensitive and specific marker to detect and quantitate granulomatous reactions in interstitial lung diseases, and is particularly useful in chronic HP cases.

Les systèmes d'évaluation des masses d'eau doivent être intercalibrés afin de s'assurer de leur harmonisation entre pays partageant les mêmes types de milieux. La France est impliquée dans 3 groupes régionaux d'inter-étalonnage (GIG Alpin, Méditerranéen et Central Baltique) et coordonne le groupe transversal travaillant sur l'ichtyofaune.

Le Cemagref accompagne le MEEDDAT et l'Onema dans la réalisation de l'intercalibration pour l'ensemble des éléments de qualité biologique pertinents (EQB) pour évaluer l'état des plans d'eau. Nous présentons ici les opérations menées en 2008 au sein des trois groupes régionaux d'inter-étalonnage (central-Baltique, alpin et méditerranéen) et dans les groupes transversaux travaillant sur le phytoplancton, les invertébrés et l'ichtyofaune. L'état d'avancement des travaux, les réflexions en cours et les perspectives 2009 sont présentés pour chacun des groupes et des EQB. » Les réalisations effectuées au sein du groupe transversal « ichtyofaune » dont nous avons la coordination sont plus particulièrement détaillées.

The glycosphingolipid patterns were analyzed on two clones derived from a human melanoma cell line and selected for their respectively high and low metastatic ability in immunosuppressed newborn rats. Conversely to the weakly metastatic cells which exhibited a pattern similar to that of the parental cell line, highly metastatic human melanoma cells appeared to be deficient in ganglioside biosynthesis. An accumulation of lactosylceramide was found in the latter cells, with low amounts of GM3 as the only ganglioside detected and a fourfold decreased activity of GM3 synthase (EC 2.4.99.9). After subcutaneous injection of metastatic cells in newborn rats, the cells proliferating in the tumor induced at the injection site re-expressed the four common gangliosides of melanoma: GM3, GM2, GD3 and GD2, whereas the cells growing in the lungs as metastatic nodules were deficient in ganglioside synthesis and showed an accumulation of lactosylceramide. Taken together, our results suggest that the human melanoma cells which are able to escape from the primary tumor and invade the lungs have an impaired ganglioside biosynthesis with a deficient GM3 synthase.