Trees tolerate an extreme heatwave via sustained transpirational cooling and increased leaf thermal tolerance

Heatwaves are likely to increase in frequency and intensity with climate change, which may impair tree function and forest C uptake. However, we have little information regarding the impact of extreme heatwaves on the physiological performance of large trees in the field. Here, we grew Eucalyptus parramattensis trees for 1 year with experimental warming (+3°C) in a field setting, until they were greater than 6 m tall. We withheld irrigation for 1 month to dry the surface soils and then implemented an extreme heatwave treatment of 4 consecutive days with air temperatures exceeding 43°C, while monitoring whole‐canopy exchange of CO₂ and H₂O, leaf temperatures, leaf thermal tolerance, and leaf and branch hydraulic status. The heatwave reduced midday canopy photosynthesis to near zero but transpiration persisted, maintaining canopy cooling. A standard photosynthetic model was unable to capture the observed decoupling between photosynthesis and transpiration at high temperatures, suggesting that climate models may underestimate a moderating feedback of vegetation on heatwave intensity. The heatwave also triggered a rapid increase in leaf thermal tolerance, such that leaf temperatures observed during the heatwave were maintained within the thermal limits of leaf function. All responses were equivalent for trees with a prior history of ambient and warmed (+3°C) temperatures, indicating that climate warming conferred no added tolerance of heatwaves expected in the future. This coordinated physiological response utilizing latent cooling and adjustment of thermal thresholds has implications for tree tolerance of future climate extremes as well as model predictions of future heatwave intensity at landscape and global scales.     

Characterization of Lipids and Proteins Associated to the Cell Wall of the Acapsular Mutant Cryptococcus neoformans Cap 67

Cryptococcus neoformans is an opportunistic human pathogen that causes life‐threatening meningitis. In this fungus, the cell wall is exceptionally not the outermost structure due to the presence of a surrounding polysaccharide capsule, which has been highly studied. Considering that there is little information about C. neoformans cell wall composition, we aimed at describing proteins and lipids extractable from this organelle, using as model the acapsular mutant C. neoformans cap 67. Purified cell wall preparations were extracted with either chloroform/methanol or hot sodium dodecyl sulfate. Total lipids fractionated in silica gel 60 were analyzed by electrospray ionization tandem mass spectrometry (ESI‐MS/MS), while trypsin digested proteins were analyzed by liquid chromatography coupled to tandem mass spectrometry (LC‐MS/MS). We detected 25 phospholipid species among phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, and phosphatidic acid. Two glycolipid species were identified as monohexosyl ceramides. We identified 192 noncovalently linked proteins belonging to different metabolic processes. Most proteins were classified as secretory, mainly via nonclassical mechanisms, suggesting a role for extracellular vesicles (EV) in transwall transportation. In concert with that, orthologs from 86% of these proteins have previously been reported both in fungal cell wall and/or in EV. The possible role of the presently described structures in fungal–host relationship is discussed.     

Development of microsatellite markers for the neotropical tree species Dipteryx alata (Fabaceae)

? Premise of the study: Microsatellite markers were developed for the population genetic analyses of the neotropical tree Dipteryx alata (Fabaceae). ? Methods and Results: Microsatellites were developed from a genomic shotgun library. Polymorphism at each microsatellite loci was analyzed based on 94 individuals from three populations. Eight loci amplified successfully and presented one to 10 alleles, and expected heterozygosities ranged from 0.097 to 0.862. Four loci also amplified in Pterodon emarginatus and presented similar polymorphism. ? Conclusion: The eight microsatellite primer pairs are potentially suitable for population genetic studies and successfully amplified in another Fabaceae species.     

Biomarker of food intake for assessing the consumption of dairy and egg products

Dairy and egg products constitute an important part of Western diets as they represent an excellent source of high-quality proteins, vitamins, minerals and fats. Dairy and egg products are highly diverse and their associations with a range of nutritional and health outcomes are therefore heterogeneous. Such associations are also often weak or debated due to the difficulty in establishing correct assessments of dietary intake. Therefore, in order to better characterize associations between the consumption of these foods and health outcomes, it is important to identify reliable biomarkers of their intake. Biomarkers of food intake (BFIs) provide an accurate measure of intake, which is independent of the memory and sincerity of the subjects as well as of their knowledge about the consumed foods. We have, therefore, conducted a systematic search of the scientific literature to evaluate the current status of potential BFIs for dairy products and BFIs for egg products commonly consumed in Europe. Strikingly, only a limited number of compounds have been reported as markers for the intake of these products and none of them have been sufficiently validated. A series of challenges hinders the identification and validation of BFI for dairy and egg products, in particular, the heterogeneous composition of these foods and the lack of specificity of the markers identified so far. Further studies are, therefore, necessary to validate these compounds and to discover new candidate BFIs. Untargeted metabolomic strategies may allow the identification of novel biomarkers, which, when taken separately or in combination, could be used to assess the intake of dairy and egg products.     

A case report on human type B botulism

A case of type B human botulism was found in Tochigi Prefecture in November, 1984. Botulinum type B toxin was detected in the serum and feces of the patient. The serum toxin was activated by trypsinization. Type B toxin was demonstrated in cooked meat medium cultures of the fecal specimens. The patient recovered after administration of type A, B, E and F quadrivalent antitoxin.     

Testing the short-term effects of a fish invader on the trophic ecology of a closely related species

The effects of invaders on native species are usually tested using species mean trait values over long time scales. However, considering individual variation over short timescales can help us better understand the interaction between invaders and native species. We compared trophic traits of the non-native guppy (Poecilia reticulata) and the native Brazilian poeciliid Phalloceros harpagos using experiments simulating the early stages of an invasive process. We used short-term mesocosms to simulate an early invasion scenario, where the two species were placed together, and a pre-invasion scenario, where species were kept separated, and analyzed interspecific and intraspecific trophic variability. We also compared the foraging efficiency of species in laboratory experiments. We found no differences on the mean diet of both species between pre and early invasion treatments. At the individual level, in the early invasion scenario, individuals of both species reduced their trophic niche as a probable effect of the presence of the heterospecific. Phalloceros harpagos had higher consumption rates than guppies indicating greater efficiency in feeding on invertebrates. Our results suggest that non-native species were not intrinsically better consumers of high-quality resources. Instead, intraspecific variation might be playing an overlooked role in shaping interactions between species during the early stages of invasion.

     

Potent Anti-Candida Fraction Isolated from Capsicum chinense Fruits Contains an Antimicrobial Peptide That is Similar to Plant Defensin and is Able to Inhibit the Activity of Different α-Amylase Enzymes

Antimicrobial peptides (AMPs) are molecules present in several life forms, possess broad-spectrum of inhibitory activity against pathogenic microorganisms, and are a promising alternative to combat the multidrug resistant pathogens. The aim of this work was to identify and characterize AMPs from Capsicum chinense fruits and to evaluate their inhibitory activities against yeasts of the genus Candida and α-amylases. Initially, after protein extraction from fruits, the extract was submitted to anion exchange chromatography resulting two fractions. Fraction D1 was further fractionated by molecular exclusion chromatography, and three fractions were obtained. These fractions showed low molecular mass peptides, and in fraction F3, only two protein bands of approximately 6.5 kDa were observed. Through mass spectrometry, we identified that the lowest molecular mass protein band of fraction F3 showed similarity with AMPs from plant defensin family. We named this peptide CcDef3 (Capsicum chinense defensin 3). The antifungal activity of these fractions was analyzed against yeasts of the genus Candida. At 200 μg/mL, fraction F1 inhibited the growth of C. tropicalis by 26%, fraction F2 inhibited 35% of the growth of C. buinensis, and fraction F3 inhibited all tested yeasts, exhibiting greater inhibition activity on the growth of the yeast C. albicans (86%) followed by C. buinensis (69%) and C. tropicalis (21%). Fractions F1 and F2 promoted membrane permeabilization of all tested yeasts and increased the endogenous induction of reactive oxygen species (ROS) in C. buinensis and C. tropicalis, respectively. We also observed that fraction F3 at a concentration of 50 µg/mL inhibited the α-amylase activities of Tenebrio molitor larvae by 96% and human salivary by 100%. Thus, our results show that fraction F3, which contains CcDef3, is a very promising protein fraction because it has antifungal potential and is able to inhibit the activity of different α-amylase enzymes.

     

The Global Epidemiology and Contribution of Cannabis Use and Dependence to the Global Burden of Disease: Results from the GBD 2010 Study

AimsEstimate the prevalence of cannabis dependence and its contribution to the global burden of disease.MethodsSystematic reviews of epidemiological data on cannabis dependence (1990-2008) were conducted in line with PRISMA and meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines. Culling and data extraction followed protocols, with cross-checking and consistency checks. DisMod-MR, the latest version of generic disease modelling system, redesigned as a Bayesian meta-regression tool, imputed prevalence by age, year and sex for 187 countries and 21 regions. The disability weight associated with cannabis dependence was estimated through population surveys and multiplied by prevalence data to calculate the years of life lived with disability (YLDs) and disability-adjusted life years (DALYs). YLDs and DALYs attributed to regular cannabis use as a risk factor for schizophrenia were also estimated.ResultsThere were an estimated 13.1 million cannabis dependent people globally in 2010 (point prevalence0.19% (95% uncertainty: 0.17-0.21%)). Prevalence peaked between 20-24 yrs, was higher in males (0.23% (0.2-0.27%)) than females (0.14% (0.12-0.16%)) and in high income regions. Cannabis dependence accounted for 2 million DALYs globally (0.08%; 0.05-0.12%) in 2010; a 22% increase in crude DALYs since 1990 largely due to population growth. Countries with statistically higher age-standardised DALY rates included the United States, Canada, Australia, New Zealand and Western European countries such as the United Kingdom; those with lower DALY rates were from Sub-Saharan Africa-West and Latin America. Regular cannabis use as a risk factor for schizophrenia accounted for an estimated 7,000 DALYs globally.ConclusionCannabis dependence is a disorder primarily experienced by young adults, especially in higher income countries. It has not been shown to increase mortality as opioid and other forms of illicit drug dependence do. Our estimates suggest that cannabis use as a risk factor for schizophrenia is not a major contributor to population-level disease burden.     

Prey Patch Patterns Predict Habitat Use by Top Marine Predators with Diverse Foraging Strategies

Spatial coherence between predators and prey has rarely been observed in pelagic marine ecosystems. We used measures of the environment, prey abundance, prey quality, and prey distribution to explain the observed distributions of three co-occurring predator species breeding on islands in the southeastern Bering Sea: black-legged kittiwakes (Rissa tridactyla), thick-billed murres (Uria lomvia), and northern fur seals (Callorhinus ursinus). Predictions of statistical models were tested using movement patterns obtained from satellite-tracked individual animals. With the most commonly used measures to quantify prey distributions - areal biomass, density, and numerical abundance - we were unable to find a spatial relationship between predators and their prey. We instead found that habitat use by all three predators was predicted most strongly by prey patch characteristics such as depth and local density within spatial aggregations. Additional prey patch characteristics and physical habitat also contributed significantly to characterizing predator patterns. Our results indicate that the small-scale prey patch characteristics are critical to how predators perceive the quality of their food supply and the mechanisms they use to exploit it, regardless of time of day, sampling year, or source colony. The three focal predator species had different constraints and employed different foraging strategies – a shallow diver that makes trips of moderate distance (kittiwakes), a deep diver that makes trip of short distances (murres), and a deep diver that makes extensive trips (fur seals). However, all three were similarly linked by patchiness of prey rather than by the distribution of overall biomass. This supports the hypothesis that patchiness may be critical for understanding predator-prey relationships in pelagic marine systems more generally.