•Mass spectrometry metabolic fingerprinting has been successfully applied to cheese.•A model cheese was inoculated with a strain of Lactococcus lactis.•Fingerprints significantly changed over time.•A ...large diversity of cheese metabolites was identified from MS fingerprints.•MS metabolic fingerprinting appears as a comprehensive and sensitive approach.
Metabolic fingerprinting is an untargeted approach which has not yet been undertaken to investigate cheese. This study is a proof of concept, concerning the ability of mass spectrometry (MS) metabolic fingerprinting to investigate modifications induced by bacterial metabolism in cheese over time. An ultrafiltrated milk concentrate was used to manufacture model cheeses inoculated with Lactococcus lactis LD61. Metabolic fingerprints were acquired after 0, 8 and 48h from two different fractions of the metabolome: the water-soluble fraction using liquid chromatography–high resolution-MS and a volatile fraction using gas chromatography–MS. Metabolic fingerprints differed significantly over time. Forty-five metabolites were identified, including well-known cheese metabolites, such as 12 amino acids and 25 volatile metabolites, and less studied ones, such as four vitamins, uric acid, creatine and l-carnitine. These results showed the relevance of cheese MS fingerprinting to generate new findings and to detect even slight differences between two conditions.
Current wastewater treatment processes are insufficient at removing many pharmaceutical and personal care products (PPCPs) from wastewater and it is necessary to identify the chemical characteristics ...that determine their fate. Models that predict the fate of various chemicals lack verification using in situ data, particularly for PPCPs. BIOWIN4 is a quantitative structure–activity relationship (QSAR) model that has been proposed to estimate the removal of PPCPs from wastewater, but data verifying the accuracy of its predictions is limited. In this study, the in situ soluble and suspended solid concentrations were assessed from raw influent, primary effluent, secondary effluent, and final effluent for 54 PPCPs and hormones over six dates. When assessing the removal efficiency across the different stages of the WWTP, the majority of the removal occurred across the secondary treatment process for the majority of the compounds. The primary treatment and disinfection process had limited impacts on the removal of most PPCPs. Sorption to solids was found to influence the removal for compounds with a log octanol–water partitioning coefficient greater than 4.5 across the secondary treatment process. For other compounds, the removal of PPCPs across the secondary treatment process was significantly correlated with the biodegradation predicted by BIOWIN4. Removal efficiencies across the aerobic secondary treatment process were predicted by integrating BIOWIN4 into pseudo-first order kinetics of PPCPs and these predicted values were compared to the in situ data. This study determines that under a certain set of operating conditions, two chemical characteristics — the expected hydrophobic interaction and the modeled biological degradation from BIOWIN4 — were found to predict the removal of highly degradable and recalcitrant PPCPs from a wastewater secondary treatment process.
► Fifty-six PPCPs were assessed across the stages of a wastewater treatment plant. ► The majority of the removal was across the secondary treatment for the majority of the PPCPs. ► BIOWIN4 and Kow values were predictive of the removal of PPCPs across a secondary treatment process. ► Predicted results using BIOWIN4 were found to correlate significantly with in situ results.
The long-term carbon cycle depends on many feedbacks. Silicate weathering consumes atmospheric CO2, but is also enhanced by the increased temperatures brought about by this important greenhouse gas. ...The long-term sensitivity ... of climate to CO...-doubling modulates the strength of this negative feedback. We update the model-experiment of Royer and others (2007) by estimating an empirical probability-density function (PDF) of ... for the Phanerozoic by using an improved GEOCARBSULF carbon-cycle model to predict a larger, recalibrated set of proxy-CO2 measurements from the present-day to 420 Ma. The new GEOCARBSULF parameterizes the rapid weathering of volcanic rocks, relative to plutonic rocks. Updates to the carbon-cycle model and the proxy-CO... data set induce opposing model responses. As a result, our experiment maintains an agreement with ... estimates based on numerical climate models and late Cenozoic paleoclimate. For a climate sensitivity ... that is uniform throughout the Phanerozoic, the most probable value is 3... to 4 ...C. GEOCARBSULF fits the proxy-CO2 data equally well, and with far more parameter choices, if ... is amplified by at least a factor of two during the glacial intervals of the Paleozoic (260-340 Ma) and Cenozoic (0-40 Ma), relative to non-glacial intervals of Earth history. For glacial amplification of two, the empirical PDFs for glacial climate sensitivity predict ... with ~99 percent probability, ... with ~95 percent probability, and ... with ~90 percent probability. The most probable values are ... to 8 ...C. This result supports the notion that the response of Earth's present-day surface temperature will be amplified by the millennial and longer-term waxing and waning of ice sheets. (ProQuest: ... denotes formulae/symbols omitted.)
The Chicxulub bolide impact caused the end-Cretaceous mass extinction of plants, but the associated selectivity and ecological effects are poorly known. Using a unique set of North Dakota leaf fossil ...assemblages spanning 2.2 Myr across the event, we show among angiosperms a reduction of ecological strategies and selection for fast-growth strategies consistent with a hypothesized recovery from an impact winter. Leaf mass per area (carbon investment) decreased in both mean and variance, while vein density (carbon assimilation rate) increased in mean, consistent with a shift towards "fast" growth strategies. Plant extinction from the bolide impact resulted in a shift in functional trait space that likely had broad consequences for ecosystem functioning.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A firm understanding of the relationship between atmospheric carbon dioxide concentration and temperature is critical for interpreting past climate change and for predicting future climate change. A ...recent synthesis suggests that the increase in global-mean surface temperature in response to a doubling of the atmospheric carbon dioxide concentration, termed 'climate sensitivity', is between 1.5 and 6.2 degrees C (5-95 per cent likelihood range), but some evidence is inconsistent with this range. Moreover, most estimates of climate sensitivity are based on records of climate change over the past few decades to thousands of years, when carbon dioxide concentrations and global temperatures were similar to or lower than today, so such calculations tend to underestimate the magnitude of large climate-change events and may not be applicable to climate change under warmer conditions in the future. Here we estimate long-term equilibrium climate sensitivity by modelling carbon dioxide concentrations over the past 420 million years and comparing our calculations with a proxy record. Our estimates are broadly consistent with estimates based on short-term climate records, and indicate that a weak radiative forcing by carbon dioxide is highly unlikely on multi-million-year timescales. We conclude that a climate sensitivity greater than 1.5 degrees C has probably been a robust feature of the Earth's climate system over the past 420 million years, regardless of temporal scaling.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The degree of leaf dissection and the presence of leaf teeth, along with tooth size and abundance, inversely correlate with mean annual temperature (MAT) across many plant communities. These ...relationships form the core of several methods for reconstructing MAT from fossils, yet the direct selection of temperature on tooth morphology has not been demonstrated experimentally. It is also not known if atmospheric CO(2) concentration affects leaf shape, limiting confidence in ancient climate reconstructions because CO(2) has varied widely on geologic timescales. Here I report the results of growing Acer rubrum (red maple) in growth cabinets at contrasting temperature and CO(2) conditions. The CO(2) treatment imparted no significant differences in leaf size and shape, while plants grown at cooler temperatures tended to have more teeth and more highly dissected leaves. These results provide direct evidence for the selection of temperature on leaf shape in one species, and support a key link in many leaf-climate methods. More broadly, these results increase confidence for using leaf shape in fossils to reconstruct paleoclimate.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The Paleocene-Eocene Thermal Maximum (PETM, 55.8 Ma), an abrupt global warming event linked to a transient increase in pCO₂, was comparable in rate and magnitude to modern anthropogenic climate ...change. Here we use plant fossils from the Bighorn Basin of Wyoming to document the combined effects of temperature and pCO₂ on insect herbivory. We examined 5,062 fossil leaves from five sites positioned before, during, and after the PETM (59-55.2 Ma). The amount and diversity of insect damage on angiosperm leaves, as well as the relative abundance of specialized damage, correlate with rising and falling temperature. All reach distinct maxima during the PETM, and every PETM plant species is extensively damaged and colonized by specialized herbivores. Our study suggests that increased insect herbivory is likely to be a net long-term effect of anthropogenic pCO₂ increase and warming temperatures.
Computerized tomography (CT) algorithms have been used mainly in the medical field but their powerful capabilities are being exploited more and more in industrial applications. This paper ...demonstrates that the technology is capable of detecting material loss on real aircraft components using embedded piezoelectric sensors on hidden surfaces. The work is novel in more than one respect. Firstly, it demonstrates that Lamb wave ultrasonic tomography can be used to accurately map material loss on an exposed aircraft surface with sensors embedded on the structure's hidden surface. Hidden, in this case, refers to the surface that is not exposed to the atmosphere-the underneath of an aircraft wing, for example. Secondly, it compares tomographic images generated by fan-beam back projection and the signal difference coefficient methods, showing clearly that the latter are more sensitive to material loss.
Leaf teeth are conspicuous and often diagnostic features of many plant species. In mesic environments with sufficient nutrient resources, the percentage of toothed species in extant floras generally ...correlates negatively with temperature; consequently, fossil leaf teeth are widely used to estimate continental paleotemperatures. However, the function of leaf teeth with respect to climate is poorly understood. Here, we test the hypothesis that teeth enhance rates of carbon uptake at the beginning of the growing season when temperatures are limiting. We measure the seasonal patterns of leaf‐margin photosynthesis and transpiration for 60 woody species from two temperate regions with differing climates (Pennsylvania and North Carolina). Three significant results are, first, physiological activity at leaf margins is greatest early in the growing season (first 30 d); second, toothed margins are more active with respect to photosynthesis and transpiration than untoothed margins; finally, leaf margins are more active in species native to colder Pennsylvania. The toothed species increase transpiration and photosynthate production early in the growing season relative to untoothed species and do so more in the Pennsylvania sample, maximizing carbon gain when temperature is limiting but moisture and nutrient availability are not. This mechanism may provide a proportionally increasing selective advantage to toothed species with decreasing temperature that is reflected in empirical correlations used for paleotemperature estimation.
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