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The Arctic is warming faster than any other region on Earth. Putting this rapid warming into perspective is challenging because instrumental records are often short or incomplete in polar regions and precisely-dated temperature proxies with high temporal resolution are largely lacking. Here, we provide this long-term perspective by reconstructing past summer temperature variability at Yamal Peninsula - a hotspot of recent warming - over the past 7638 years using annually resolved tree-ring records. We demonstrate that the recent anthropogenic warming interrupted a multi-millennial cooling trend. We find the industrial-era warming to be unprecedented in rate and to have elevated the summer temperature to levels above those reconstructed for the past seven millennia (in both 30-year mean and the frequency of extreme summers). This is undoubtedly of concern for the natural and human systems that are being impacted by climatic changes that lie outside the envelope of natural climatic variations for this region., (© 2022. The Author(s).)

Essentials Cysteine oxidation to sulfenic acid plays a key role in redox regulation and signal transduction. Platelet sulfenylome was studied by quantitative proteomics in pathogen inactivated platelets. One hundred and seventy-four sulfenylated proteins were identified in resting platelets. Pathogen inactivation oxidized integrin βIII, which could activate the mitogen-activated protein kinases pathway. ABSTRACT: Background Cysteine-containing protein modifications are involved in numerous biological processes such redox regulation or signal transduction. During the preparation and storage of platelet concentrates, cell functions and protein regulations are impacted. In spite of several proteomic investigations, the platelet sulfenylome, ie, the proteins containing cysteine residues (R-SH) oxidized to sulfenic acid (R-SOH), has not been characterized. Methods A dimedone-based sulfenic acid tagging and enrichment coupled to a mass spectrometry identification workflow was developed to identify and quantify the sulfenic acid-containing proteins in platelet concentrates treated or not with an amotosalen/ultraviolet A (UVA) pathogen inactivation technique. Results One hundred and seventy-four sulfenylated proteins were identified belonging mainly to the integrin signal pathway and cytoskeletal regulation by Rho GTPase. The impact on pathogen inactivated platelet concentrates was weak compared to untreated ones where three sulfenylated proteins (myosin heavy chain 9, integrin βIII, and transgelin 2) were significantly affected by amotosalen/UVA treatment. Of particular interest, the reported oxidation of cysteine residues in integrin βIII is known to activate the receptor αIIbβIII. Following the pathogen inactivation, it might trigger the phosphorylation of p38MAPK and explain the lesions reported in the literature. Moreover, procaspase activating compound-1 (PAC-1) binding assays on platelet activation showed an increased response to adenosine diphosphate exacerbated by the tagging of proteins with dimedone. This result corroborates the hypothesis of an oxidation-triggered activation of αIIbβIII by the pathogen inactivation treatment. Conclusions The present work completes missing information on the platelet proteome and provides new insights on the effect of pathogen inactivation linked to integrin signaling and cytoskeleton regulation., (© 2020 International Society on Thrombosis and Haemostasis.)

The emergence of antibiotic resistance represents a major threat to human health. In this work we investigated the elimination of antibiotic resistant bacteria (ARB) by solar light and solar photo-Fenton processes. As such, we have designed an experimental plan in which several bacterial strains (Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae) possessing different drug-susceptible and -resistant patterns and structures (Gram-positive and Gram-negative) were subjected to solar light and the photo-Fenton oxidative treatment in water. We showed that both solar light and solar photo-Fenton processes were effective in the elimination of ARB in water and that the time necessary for solar light disinfection and solar photo-Fenton disinfection were similar for antibiotic-susceptible and antibiotic-resistant strains (mostly 180-240 and 90-120 min, respectively). Moreover, the bacterial structure did not significantly affect the effectiveness of the treatment. Similar regrowth pattern was observed (compared to the susceptible strain) and no development of bacteria with higher drug-resistance values was found in waters after any treatment. Finally, both processes were effective to reduce AR genes (ARGs), although solar photo-Fenton was more rapid than solar light. In conclusion, the solar photo-Fenton process ensured effective disinfection of ARB and elimination of ARGs in water (or wastewater) and is a potential mean to ensure limitation of ARB and ARG spread in nature., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Climate model projections suggest widespread drying in the Mediterranean Basin and wetting in Fennoscandia in the coming decades largely as a consequence of greenhouse gas forcing of climate. To place these and other "Old World" climate projections into historical perspective based on more complete estimates of natural hydroclimatic variability, we have developed the "Old World Drought Atlas" (OWDA), a set of year-to-year maps of tree-ring reconstructed summer wetness and dryness over Europe and the Mediterranean Basin during the Common Era. The OWDA matches historical accounts of severe drought and wetness with a spatial completeness not previously available. In addition, megadroughts reconstructed over north-central Europe in the 11th and mid-15th centuries reinforce other evidence from North America and Asia that droughts were more severe, extensive, and prolonged over Northern Hemisphere land areas before the 20th century, with an inadequate understanding of their causes. The OWDA provides new data to determine the causes of Old World drought and wetness and attribute past climate variability to forced and/or internal variability.

This paper presents a multi-century, maximum latewood density (MXD) chronology developed from living and sub-fossil spruce trees from the Eastern Alps. The chronology is continuous from 88AD to 2008AD. This time series has been analysed with respect to its possible use for climate reconstruction. Correlations with climatic data showed strong dependence between MXD of growth rings and temperature of April, May, June, July, August and September and a weaker, negative dependence with precipitation of May and September. For solar radiation a positive relationship was noted for April, July, August and September. Light rings were frequently observed within the analysed samples and the climate of years with light rings was examined. Mean monthly temperatures in January, June, August, September and October, averaged during light ring years, were cooler than during years without light rings. Precipitation was also significantly reduced in March during light ring years. In turn, solar radiation during light ring years has significantly lowered values in February and August. The occurrence of light rings was often positively related to strong volcanic events.

An annually resolved and absolutely dated ring-width chronology spanning 4,500 y has been constructed using subfossil, archaeological, and living-tree juniper samples from the northeastern Tibetan Plateau. The chronology represents changing mean annual precipitation and is most reliable after 1500 B.C. Reconstructed precipitation for this period displays a trend toward more moist conditions: the last 10-, 25-, and 50-y periods all appear to be the wettest in at least three and a half millennia. Notable historical dry periods occurred in the 4th century BCE and in the second half of the 15th century CE. The driest individual year reconstructed (since 1500 B.C.) is 1048 B.C., whereas the wettest is 2010. Precipitation variability in this region appears not to be associated with inferred changes in Asian monsoon intensity during recent millennia. The chronology displays a statistical association with the multidecadal and longer-term variability of reconstructed mean Northern Hemisphere temperatures over the last two millennia. This suggests that any further large-scale warming might be associated with even greater moisture supply in this region.

There is controversy regarding the limiting climatic factor for tree radial growth at the alpine treeline on the northeastern Tibetan Plateau. In this study, we collected 594 increment cores from 331 trees, grouped within four altitude belts spanning the range 3550 to 4020 m.a.s.l. on a single hillside. We have developed four equivalent ring-width chronologies and shown that there are no significant differences in their growth-climate responses during 1956 to 2011 or in their longer-term growth patterns during the period AD 1110-2011. The main climate influence on radial growth is shown to be precipitation variability. Missing ring analysis shows that tree radial growth at the uppermost treeline location is more sensitive to climate variation than that at other elevations, and poor tree radial growth is particularly linked to the occurrence of serious drought events. Hence water limitation, rather than temperature stress, plays the pivotal role in controlling the radial growth of Sabina przewalskii Kom. at the treeline in this region. This finding contradicts any generalisation that tree-ring chronologies from high-elevation treeline environments are mostly indicators of temperature changes.

We combine satellite and ground observations during 1950-2011 to study the long-term links between multiple climate (air temperature and cryospheric dynamics) and vegetation (greenness and atmospheric CO(2) concentrations) indicators of the growing season of northern ecosystems (>45°N) and their connection with the carbon cycle. During the last three decades, the thermal potential growing season has lengthened by about 10.5 days (P < 0.01, 1982-2011), which is unprecedented in the context of the past 60 years. The overall lengthening has been stronger and more significant in Eurasia (12.6 days, P < 0.01) than North America (6.2 days, P > 0.05). The photosynthetic growing season has closely tracked the pace of warming and extension of the potential growing season in spring, but not in autumn when factors such as light and moisture limitation may constrain photosynthesis. The autumnal extension of the photosynthetic growing season since 1982 appears to be about half that of the thermal potential growing season, yielding a smaller lengthening of the photosynthetic growing season (6.7 days at the circumpolar scale, P < 0.01). Nevertheless, when integrated over the growing season, photosynthetic activity has closely followed the interannual variations and warming trend in cumulative growing season temperatures. This lengthening and intensification of the photosynthetic growing season, manifested principally over Eurasia rather than North America, is associated with a long-term increase (22.2% since 1972, P < 0.01) in the amplitude of the CO(2) annual cycle at northern latitudes. The springtime extension of the photosynthetic and potential growing seasons has apparently stimulated earlier and stronger net CO(2) uptake by northern ecosystems, while the autumnal extension is associated with an earlier net release of CO(2) to the atmosphere. These contrasting responses may be critical in determining the impact of continued warming on northern terrestrial ecosystems and the carbon cycle., (© 2013 John Wiley & Sons Ltd.)

It is generally hypothesized that tree growth at the upper treeline is normally controlled by temperature while that at the lower treeline is precipitation limited. However, uniform patterns of inter-annual ring-width variations along altitudinal gradients are also observed in some situations. How changing elevation influences tree growth in the cold and arid Qilian Mountains, on the northeastern Tibetan Plateau, is of considerable interest because of the sensitivity of the region's local climate to different atmospheric circulation patterns. Here, a network of four Qilian juniper (Sabina przewalskii Kom.) ring-width chronologies was developed from trees distributed on a typical mountain slope at elevations ranging from 3000 to 3520 m above sea level (a.s.l.). The statistical characteristics of the four tree-ring chronologies show no significant correlation with increasing elevation. All the sampled tree growth was controlled by a common climatic signal (local precipitation) across the investigated altitudinal gradient (520 m). During the common reliable period, covering the past 450 years, the four chronologies have exhibited coherent growth patterns in both the high- and low-frequency domains. These results contradict the notion of contrasting climate growth controls at higher and lower elevations, and specifically the assumption that inter-annual tree-growth variability is controlled by temperature at the upper treeline. It should be stressed that these results relate to the relatively arid conditions at the sampling sites in the Qilian Mountains.

This paper describes variability in trends of annual tree growth at several locations in the high latitudes of Eurasia, providing a wide regional comparison over a 2000-year period. The study focuses on the nature of local and widespread tree-growth responses to recent warming seen in instrumental observations, available in northern regions for periods ranging from decades to a century. Instrumental temperature data demonstrate differences in seasonal scale of Eurasian warming and the complexity and spatial diversity of tree-growing-season trends in recent decades. A set of long tree-ring chronologies provides empirical evidence of association between inter-annual tree growth and local, primarily summer, temperature variability at each location. These data show no evidence of a recent breakdown in this association as has been found at other high-latitude Northern Hemisphere locations. Using Kendall's concordance, we quantify the time-dependent relationship between growth trends of the long chronologies as a group. This provides strong evidence that the extent of recent widespread warming across northwest Eurasia, with respect to 100- to 200-year trends, is unprecedented in the last 2000 years. An equivalent analysis of simulated temperatures using the HadCM3 model fails to show a similar increase in concordance expected as a consequence of anthropogenic forcing.