Climatic adaptation and ecological divergence between two closely related pine species in Southeast China

Climate is one of the most important drivers for adaptive evolution in forest trees. Climatic selection contributes greatly to local adaptation and intraspecific differentiation, but this kind of selection could also have promoted interspecific divergence through ecological speciation. To test this hypothesis, we examined intra‐ and interspecific genetic variation at 25 climate‐related candidate genes and 12 reference loci in two closely related pine species, Pinus massoniana Lamb. and Pinus hwangshanensis Hisa, using population genetic and landscape genetic approaches. These two species occur in Southeast China but have contrasting ecological preferences in terms of several environmental variables, notably altitude, although hybrids form where their distributions overlap. One or more robust tests detected signals of recent and/or ancient selection at two‐thirds (17) of the 25 candidate genes, at varying evolutionary timescales, but only three of the 12 reference loci. The signals of recent selection were species specific, but signals of ancient selection were mostly shared by the two species likely because of the shared evolutionary history. F_ST outlier analysis identified six SNPs in five climate‐related candidate genes under divergent selection between the two species. In addition, a total of 24 candidate SNPs representing nine candidate genes showed significant correlation with altitudinal divergence in the two species based on the covariance matrix of population history derived from reference SNPs. Genetic differentiation between these two species was higher at the candidate genes than at the reference loci. Moreover, analysis using the isolation‐with‐migration model indicated that gene flow between the species has been more restricted for climate‐related candidate genes than the reference loci, in both directions. Taken together, our results suggest that species‐specific and divergent climatic selection at the candidate genes might have counteracted interspecific gene flow and played a key role in the ecological divergence of these two closely related pine species.     

Fibrillar β‐amyloid 1‐42 alters cytokine secretion,cholinergic signalling and neuronal differentiation

Adult neurogenesis is impaired by inflammatory processes, which are linked to altered cholinergic signalling and cognitive decline in Alzheimer's disease. In this study, we investigated how amyloid beta (Aβ)‐evoked inflammatory responses affect the generation of new neurons from human embryonic stem (hES) cells and the role of cholinergic signalling in regulating this process. The hES were cultured as neurospheres and exposed to fibrillar and oligomeric Aβ_1‐42 (Aβf, AβO) or to conditioned medium from human primary microglia activated with either Aβ_1‐42 or lipopolysaccharide. The neurospheres were differentiated for 29 days in vitro and the resulting neuronal or glial phenotypes were thereafter assessed. Secretion of cytokines and the enzymes acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) and choline acetyltransferase (ChAT) involved in cholinergic signalling was measured in medium throughout the differentiation. We report that differentiating neurospheres released various cytokines, and exposure to Aβf, but not AβO, increased the secretion of IL‐6, IL‐1β and IL‐2. Aβf also influenced the levels of AChE, BuChE and ChAT in favour of a low level of acetylcholine. These changes were linked to an altered secretion pattern of cytokines. A different pattern was observed in microglia activated by Aβf, demonstrating decreased secretion of TNF‐α, IL‐1β and IL‐2 relative to untreated cells. Subsequent exposure of differentiating neurospheres to Aβf or to microglia‐conditioned medium decreased neuronal differentiation and increased glial differentiation. We suggest that a basal physiological secretion of cytokines is involved in shaping the differentiation of neurospheres and that Aβf decreases neurogenesis by promoting a microenvironment favouring hypo‐cholinergic signalling and gliogenesis.     

Bone Health and Risk Factors of Cardiovascular Disease - A Cross-Sectional Study in Healthy Young Adults

Objective

Both osteoporosis and cardiovascular disease (CVD) are diseases that comprise a growing medical and economic burden in ageing populations. They share many risk factors, including ageing, low phy-sical activity, and possibly overweight. We aimed to study associations between individual risk factors for CVD and bone mineral density (BMD) and turnover markers (BTMs) in apparently healthy cohort.

Design

A cross-sectional assessment of 155 healthy 32-year-old adults (74 males) was performed for skeletal status, CVD risk factors and lifestyle factors.

Methods

We analysed serum osteocalcin, procollagen I aminoterminal propeptide (P1NP), collagen I carboxy-terminal telopeptide (ICTP) and urine collagen I aminoterminal telopeptide (U-NTX), as well as serum insulin, plasma glucose, triglyceride and HDL-cholesterol levels. BMD, fat and lean mass were asses-sed using DXA scanning. Associations were tested with partial correlations in crude and adjusted mo-dels. Bone status was compared between men with or without metabolic syndrome (defined according to the NCEP-ATPIII criteria) with multivariate analysis.

Results

Osteocalcin and P1NP correlated inversely with insulin (R = −0.243, P = 0.003 and R = −0.187, P = 0.021) and glucose (R = −0.213, P = 0.009 and R = −0.190, P = 0.019), but after controlling for fat mass and lifestyle factors, the associations attenuated with insulin (R = −0.162, P = 0.053 and R = −0.093, P = 0.266) and with glucose (R = −0.099, P = 0.240 and R = −0.133, P = 0.110), respectively. Whole body BMD associated in-versely only with triglycerides in fully adjusted model. In men with metabolic syndrome, whole body BMD, osteocalcin and P1NP were lower compared to healthy men, but these findings disappeared in fully adjusted model.

Conclusions

In young adults, inverse associations between BTM/BMD and risk factors of CVD appeared in crude models, but after adjusting for fat mass, no association continued to be present. In addition to fat mass, lifestyle factors, especially physical activity, modified the associations between CVD and bone charac-teristics. Prospective studies are needed to specify the role of mediators and lifestyle factors in the prevention of CVD and osteoporosis.     

Antigenic Differences between AS03 Adjuvanted Influenza A (H1N1) Pandemic Vaccines: Implications for Pandemrix-Associated Narcolepsy Risk

Background

Narcolepsy results from immune-mediated destruction of hypocretin secreting neurons in hypothalamus, however the triggers and disease mechanisms are poorly understood. Vaccine-attributable risk of narcolepsy reported so far with the AS03 adjuvanted H1N1 vaccination Pandemrix has been manifold compared to the AS03 adjuvanted Arepanrix, which contained differently produced H1N1 viral antigen preparation. Hence, antigenic differences and antibody response to these vaccines were investigated.

Methods and Findings

Increased circulating IgG-antibody levels to Pandemrix H1N1 antigen were found in 47 children with Pandemrix-associated narcolepsy when compared to 57 healthy children vaccinated with Pandemrix. H1N1 antigen of Arepanrix inhibited poorly these antibodies indicating antigenic difference between Arepanrix and Pandemrix. High-resolution gel electrophoresis quantitation and mass spectrometry identification analyses revealed higher amounts of structurally altered viral nucleoprotein (NP) in Pandemrix. Increased antibody levels to hemagglutinin (HA) and NP, particularly to detergent treated NP, was seen in narcolepsy. Higher levels of antibodies to NP were found in children with DQB1*06∶02 risk allele and in DQB1*06∶02 transgenic mice immunized with Pandemrix when compared to controls.

Conclusions

This work identified 1) higher amounts of structurally altered viral NP in Pandemrix than in Arepanrix, 2) detergent-induced antigenic changes of viral NP, that are recognized by antibodies from children with narcolepsy, and 3) increased antibody response to NP in association of DQB1*06∶02 risk allele of narcolepsy. These findings provide a link between Pandemrix and narcolepsy. Although detailed mechanisms of Pandemrix in narcolepsy remain elusive, our results move the focus from adjuvant(s) onto the H1N1 viral proteins.     

Bacterial populations on brewery filling hall surfaces as revealed by next-generation sequencing

Due to the presence of moisture and nutrients, brewery filling line surfaces are susceptible to unwanted microbial attachment. Knowledge of the attaching microbes will aid in designing hygienic control of the process. In this study the bacterial diversity present on brewery filling line surfaces was revealed by next generation sequencing. The two filling lines studied maintained their characteristic bacterial community throughout three sampling times (13–163 days). On the glass bottle line, γ-proteobacteria dominated (35–82% of all OTUs), whereas on the canning line α-, β- and γ-proteobacteria and actinobacteria were most common. The most frequently detected genera were Acinetobacter, Propinobacterium and Pseudomonas. The halophilic genus Halomonas was commonly detected, which might be due to its tolerance to alkaline foam cleaners. This study has revealed a detailed overall picture of the bacterial groups present on filling line surfaces. Further effort should be given to determine the efficacy of washing procedures on different bacterial groups.     

Genetic comparison between Pinus sylvestris and P. mugo using isozymes and chloroplast DNA

Pinus sylvestris and P. mugo populations from Poland and Czechoslovakia were compared using genetic variability at isozyme markers, chloroplast DNA variation, and mating system measurements. Two isozyme loci were found to differ between the species. P. mugo was as variable at isozyme loci as P. sylvestris. Diagnostic cpDNA fragments were found using the restriction enzyme Bcl-I. Populations that were morphologically classified as hybrids were found to be pure species, based both on isozyme and cpDNA results.     

A modeling and simulation perspective on the mechanism and function of respiratory complex I

Respiratory complex I is a giant redox-driven proton pump, and central to energy production in mitochondria and bacteria. It catalyses the reduction of quinone to quinol, and converts the free energy released into the endergonic proton translocation across the membrane. The proton pumping sets up the proton electrochemical gradient, which propels the synthesis of ATP. Despite the availability of extensive biochemical, biophysical and structural data on complex I, the mechanism of coupling between the electron and proton transfer reactions remain uncertain. In this work, we discuss current state-of-the-art in the field with particular emphasis on the molecular mechanism of respiratory complex I, as deduced from computational modeling and simulation approaches, but in strong alliance with the experimental data. This leads to novel synthesis of mechanistic ideas on a highly complex enzyme of the electron transport chain that has been associated with a number of mitochondrial and neurodegenerative disorders.     

Nitrogen transformations in limed and nitrogen fertilized soil in Norway spruce stands

Nitrogen transformations in the soil, and the resulting changes in carbon and nitrogen compounds in soil percolate water, were studied in two stands of Norway spruce (Picea abies L.). Over the last 30 years the stands were repeatedly limed (total 6000 kg ha^–1), fertilized with nitrogen (total about 900 kg ha^–1), or both treatments together. Both aerobic incubations of soil samples in the laboratory, and intact soil core incubations in the field showed that in control plots ammonification widely predominated over nitrification. In both experiments nitrogen addition increased the formation of mineral-N. In one experiment separate lime and nitrogen treatments increased nitrification, in the other, only lime and nitrogen addition together had this effect. In one experiment immobilization of nitrogen to soil microbial biomass was lower in soil only treated with nitrogen. Soil percolate water was collected by means of lysimeters placed under the humus layer and 10 cm below in the mineral soil. Total N, NH₄-N and NO₃-N were measured, and dissolved organic nitrogen was fractioned according to molecular weight. NO₃-N concentrations in percolate water, collected under the humus layer, were higher in plots treated with N-fertilizer, especially when lime was also added. The treatments had no effect on the N concentrations in mineral soil. A considerable proportion of nitrogen was leached in organic form.     

Transgene inactivation inPetunia hybrida is influenced by the properties of the foreign gene

Petunia mutant RL01 was transformed with maizeA1 and gerberagdfr cDNAs, which both encode dihydroflavonol-4-reductase (DFR) activity. The sameAgrobacterium vector and the same version of the CaMV 35S promoter were used in both experiments. Transformation with the cDNAs resulted in production of pelargonidin pigments in the transformants. However, theA1 andgdfr transformants showed clearly different phenotypes. The flowers of the primaryA1 transformants were pale and showed variability in pigmentation during their growth, while the flowers of thegdfr transformants showed intense and highly stable coloration. The color difference in the primary transformants was reflected in the expression levels of the transgenes as well as in the levels of anthocyanin pigment. As previously reported by others, the instability in pigmentation in theA1 transformants was more often detected in clones with multiple copies of the transgene and was associated with methylation of the 35S promoter and of the transgene cDNA itself. In thegdfr transformants, the most intense pigmentation was observed in plants with multiple transgenes in their genome. Only rarely was partial methylation of the 35S promoter detected, while thegdfr cDNA always remained in an unmethylated state. We conclude that the properties of the transgene itself strongly influence the inactivation process. The dicotyledonousgdfr cDNA with a lower GC content and fewer possible methylation sites is more compatible the genomic organization of petunia and this prevents it being recognized as a foreign gene and hence silenced by methylation.     

Multiple defaults: feminine -<Emphasis Type="Italic">et</Emphasis> and -<Emphasis Type="Italic">a</Emphasis> in Hebrew present tense

In this paper, we study the distribution of the feminine singular suffixes -et and -a in the present tense of Hebrew verb paradigms. The question we ask is which of these two suffixes is the default allomorph. The answer is not trivial. In terms of distribution, -a appears with limited environments and -et is clearly the elsewhere case, and thus the default. In terms of order, however, -et is the feminine singular suffix associated with the present tense, while -a emerges only when -et is blocked. We thus argue for multiple defaults, distinguishing between local and global default; -et is the local default, uniquely associated with feminine singular verbs in the present tense, while -a is the global default, associated with feminine singular but not specified for the present tense. We provide a formal analysis for the distribution of these suffixes within the framework of Optimality Theory, which allows the interaction of phonological constraints with constraints on morpho-syntactic feature mapping. We further study the partially unpredictable distribution of -et and -a in vowel final verbs, and present the results of an experiment where speakers employed unique strategies in order to assign the local default -et.