Land use practices and ectomycorrhizal fungal communities from oak woodlands dominated by Quercus suber L. considering drought scenarios

Oak woodlands in the Mediterranean basin have been traditionally converted into agro-silvo-pastoral systems and exemplified sustainable land use in Europe. In Portugal, in line with the trend of other European countries, profound changes in management options during the twentieth century have led to landscape simplification. Landscapes are dynamic and the knowledge of future management planning combining biological conservation and soil productivity is needed, especially under the actual scenarios of drought and increasing evidence of heavy oak mortality. We examined the ectomycorrhizal (ECM) fungal community associated with cork oak in managed oak woodlands (called montado) under different land use practices, during summer. ECM fungal richness and abundance were assessed in 15 stands established in nine montados located in the Alentejo region (southern Portugal), using morphotyping and ITS rDNA analysis. Parameters related to the montados landscape characteristics, land use history over the last 25 years, climatic and edaphic conditions were taken into account. Fifty-five ECM fungal taxa corresponding to the most abundant fungal symbionts were distinguished on cork oak roots. Cenococcum geophilum and the families Russulaceae and Thelephoraceae explained 56% of the whole ECM fungal community; other groups were represented among the community: Cortinariaceae, Boletaceae, Amanita, Genea, Pisolithus, Scleroderma, and Tuber. There were pronounced differences in ECM fungal community structure among the 15 montados stands: C. geophilum was the only species common to all stands, tomentelloid and russuloid species were detected in 87–93% of the stands, Cortinariaceae was detected in 60% of the stands, and the other groups were more unequally distributed. Ordination analysis revealed that ECM fungal richness was positively correlated with the silvo-pastoral exploitation regime and low mortality of cork oak, while ECM fungal abundance was positively correlated with extensive agro-silvo-pastoral exploitation under a traditional 9-year rotation cultivation system and recent soil tillage. The effects of land use on the ECM fungal community and its implications in different scenarios of landscape management options, oak mortality, and global warming are discussed.     

Redox-sensitive prosurvival and proapoptotic protein expression in the myocardial remodeling post-infarction in rats

In this study, we investigated the oxidative stress influence in some prosurvival and proapoptotic proteins after myocardial infarction (MI). Male Wistar rats were divided in two groups: Sham-operated (control) and MI. MI was induced by left coronary artery occlusion. 28-days after surgery, echocardiographic, morphometric, and hemodynamic parameters were evaluated. Redox status (reduced to oxidized glutathione ratio, GSH/GSSG) and hydrogen peroxide levels (H₂O₂) were measured in heart tissue. The p-ERK/ERK, p-Akt/Akt, p-mTOR/mTOR and p-GSK-3β/GSK-3β ratios, as well as apoptosis-inducing factor (AIF) myocardial protein expression were quantified by Western blot. MI group showed an increase in cardiac hypertrophy (23%) associated with a decrease in ejection fraction (38%) and increase in left ventricular end-diastolic pressure (82%) when compared to control, characterizing ventricular dysfunction. Redox status imbalance was seen in MI animals, as evidenced by the decrease in the GSH/GSSG ratio (30%) and increased levels of H₂O₂ (45%). This group also showed an increase in the ERK phosphorylation and a reduction of Akt and mTOR phosphorylation when compared to control. Moreover, we showed a reduction in the GSK-3β phosphorylation and an increase in AIF protein expression in MI group. Taken together, our results show increased H₂O₂ levels and cellular redox imbalance associated to a higher p-ERK and AIF immunocontent, which would contribute to a maladaptive hypertrophy phenotype.     

Synopsis of <Emphasis Type="Italic">Mickelia</Emphasis>, a newly recognized genus of bolbitidoid ferns (Dryopteridaceae)

Our recent molecular phylogenetic study revealed a previously unrecognized clade of six species that is sister to Elaphoglossum. Within this clade, four species are currently classified in Bolbitis, one in Lomagramma, and one in Acrostichum. For this clade, we propose the name Mickelia, with M. nicotianifolia as the type species. We also make new combinations for the species in our phylogenetic study shown to belong to Mickelia (M. bernoullii, M. guianensis, M. hemiotis, M. nicotianifolia, M. oligarchica, and M. scandens) and two other species believed to belong to the clade based on morphology (M. lindigii, M. pergamentacea). A new hybrid and two new species are also described (M. ×atrans, M. furcata, and M. pradoi). In total, Mickelia consists of ten species and one hybrid. It is entirely neotropical. We provide a key to the genera of bolbitidoid ferns and a synopsis of Mickelia that gives for each species a complete synonymy, geographical distribution, comparative discussion, and illustration.     

What makes a species central in a cleaning mutualism network?

Mutualisms often form networks of interacting species, characterized by the existence of a central core of species that potentially drive the ecology and the evolution of the whole community. Centrality measures allow quantification of how central or peripheral a species is within a network, thus informing about the role of each species in network organization, dynamics, and stability. In the present study we addressed the question whether the structural position of species in the network (i.e. their topological importance) relates to their ecological traits. We studied interactions between cleaner and client reef fishes to identify central and peripheral species within a mutualistic network, and investigated five ecological correlates. We used three measures to estimate the level of centrality of a species for distinct structural patterns, such as the number of interactions and the structural proximity to other species. Through the use of a principal component analysis (PCA) we observed that the centrality measures were highly correlated (92.5%) in the studied network, which indicates that the same species plays a similar role for the different structural patterns. Three cleaner and ten client species had positive values of centrality, which suggests that these species are modulating ecological and evolutionary dynamics within the network. Higher centralities were related to higher abundances and feeding habits for client fishes, but not for cleaners. The high correlation between centrality measures in the present study is likely related to the nested structure of the cleaning network. The cleaner species’ set, by having central species that are not necessarily the most abundant ones, bears potentially more vulnerable points for network cohesiveness. Additionally, the present study generalizes previous findings for plant–animal mutualisms, as it shows that the structure of marine mutualisms is also related to a complex interplay between abundance and niche‐related features.     

PYR/PYL/RCAR family members are major in‐vivo ABI1 protein phosphatase 2C‐interacting proteins in Arabidopsis

Abscisic acid (ABA) mediates resistance to abiotic stress and controls developmental processes in plants. The group‐A PP2Cs, of which ABI1 is the prototypical member, are protein phosphatases that play critical roles as negative regulators very early in ABA signal transduction. Because redundancy is thought to limit the genetic dissection of early ABA signalling, to identify redundant and early ABA signalling proteins, we pursued a proteomics approach. We generated YFP‐tagged ABI1 Arabidopsis expression lines and identified in vivo ABI1‐interacting proteins by mass‐spectrometric analyses of ABI1 complexes. Known ABA signalling components were isolated including SnRK2 protein kinases. We confirm previous studies in yeast and now show that ABI1 interacts with the ABA‐signalling kinases OST1, SnRK2.2 and SnRK2.3 in plants. Interestingly, the most robust in planta ABI1‐interacting proteins in all LC‐MS/MS experiments were nine of the 14 PYR/PYL/RCAR proteins, which were recently reported as ABA‐binding signal transduction proteins, providing evidence for in vivo PYR/PYL/RCAR interactions with ABI1 in Arabidopsis. ABI1–PYR1 interaction was stimulated within 5 min of ABA treatment in Arabidopsis. Interestingly, in contrast, PYR1 and SnRK2.3 co‐immunoprecipitated equally well in the presence and absence of ABA. To investigate the biological relevance of the PYR/PYLs, we analysed pyr1/pyl1/pyl2/pyl4 quadruple mutant plants and found strong insensitivities in ABA‐induced stomatal closure and ABA‐inhibition of stomatal opening. These findings demonstrate that ABI1 can interact with several PYR/PYL/RCAR family members in Arabidopsis, that PYR1–ABI1 interaction is rapidly stimulated by ABA in Arabidopsis and indicate new SnRK2 kinase‐PYR/PYL/RCAR interactions in an emerging model for PYR/PYL/RCAR‐mediated ABA signalling.     

Towards an assessment of multiple ecosystem processes and services via functional traits

Managing ecosystems to ensure the provision of multiple ecosystem services is a key challenge for applied ecology. Functional traits are receiving increasing attention as the main ecological attributes by which different organisms and biological communities influence ecosystem services through their effects on underlying ecosystem processes. Here we synthesize concepts and empirical evidence on linkages between functional traits and ecosystem services across different trophic levels. Most of the 247 studies reviewed considered plants and soil invertebrates, but quantitative trait–service associations have been documented for a range of organisms and ecosystems, illustrating the wide applicability of the trait approach. Within each trophic level, specific processes are affected by a combination of traits while particular key traits are simultaneously involved in the control of multiple processes. These multiple associations between traits and ecosystem processes can help to identify predictable trait–service clusters that depend on several trophic levels, such as clusters of traits of plants and soil organisms that underlie nutrient cycling, herbivory, and fodder and fibre production. We propose that the assessment of trait–service clusters will represent a crucial step in ecosystem service monitoring and in balancing the delivery of multiple, and sometimes conflicting, services in ecosystem management.     

Dimethylaminopyridine derivatives of lupane triterpenoids are potent disruptors of mitochondrial structure and function

Development of mitochondrially-targeted drugs is receiving increasing attention because of the central roles these organelles play in energy production, reactive oxygen generation, and regulation of cell death pathways. Previous studies have demonstrated that both natural and synthetic triterpenoids can disrupt mitochondrial structure and function. In this study, we tested the ability of a number of dimethylaminopyridine (DMAP) derivatives of lupane triterpenoids to target mitochochondria in two human melanoma cell lines and an untransformed normal fibroblast line. These compounds induced a striking fragmentation and depolarization of the mitochondrial network, along with an inhibition of cell proliferation. A range of potencies among these compounds was noted, which was correlated with the number, position, and orientation of the DMAP groups. Overall, the extent of proliferation inhibition mirrored the effectiveness of mitochondrial disruption. Thus, DMAP derivatives of lupane triterpenoids can be potent mitochondrial perturbants that appear to suppress cell growth primarily via their mitochondrial effects.     

Postural reactions following forward platform perturbation in young,middle-age,and old adults

The aim of the study was to examine how individuals of different ages react to forward balance perturbations. Thirty-six volunteers, divided into four groups [young (YA), middle-age (MA₄₀ and MA₅₀), and old (OA) adults], stood on a platform that was either kept stationary, moved backward, or moved forward. EMG onset, EMG time-to-peak, iEMG, and agonist–antagonist co-activation, as well as cumulative angular excursion, maximum center of mass (CM) backward displacement, and CM time-to-reversal were assessed after forward translations. Postural synergies were assessed using principal component analysis (PCA). The results showed that OA activated their muscles later than YA [TA = 25 ms, RF = 17 ms] and OA and MA₅₀ reached the peak of activation later than YA [MA₅₀:TA = 23 ms, RF = 32 ms, OA:TA = 28 ms, RF = 21 ms]. Moreover, OA kept a higher level of activation longer than all younger groups. No differences among groups were observed in co-activation, kinematic, and PCA variables. We conclude that changes in temporal EMG patterns can be seen in the fifth decade. However, such changes have no effect on the CM horizontal displacement and CM time-to-reversal after perturbation, which cannot be justified by the use of different postural synergies, suggesting that temporal aspects of muscle activation could play a minor role in controlling excessive CM displacements after perturbations.     

Live, attenuated strains of Listeria and Salmonella as vaccine vectors in cancer treatment

Live, attenuated strains of many bacteria that synthesize and secrete foreign antigens are being developed as vaccines for a number of infectious diseases and cancer. Bacterial-based vaccines provide a number of advantages over other antigen delivery strategies including low cost of production, the absence of animal products, genetic stability and safety. In addition, bacterial vaccines delivering a tumor-associated antigen (TAA) stimulate innate immunity and also activate both arms of the adaptive immune system by which they exert efficacious anti-tumor effects. Listeria monocytogenes and several strains of Salmonella have been most extensively studied for this purpose. A number of attenuated strains have been generated and used to deliver antigens associated with infectious diseases and cancer. Although both bacteria are intracellular, the immune responses invoked by Listeria and Salmonella are different due to their sub-cellular locations. Upon entering antigen-presenting cells by phagocytosis, Listeria is capable of escaping from the phagosomal compartment and thus has direct access to the cell cytosol. Proteins delivered by this vector behave as endogenous antigens, are presented on the cell surface in the context of MHC class I molecules, and generate strong cell-mediated immune responses. In contrast, proteins delivered by Salmonella, which lacks a phagosomal escape mechanism, are treated as exogenous antigens and presented by MHC class II molecules resulting predominantly in Th2 type immune responses. This fundamental disparity between the life cycles of the two vectors accounts for their differential application as antigen delivery vehicles. The present paper includes a review of the most recent advances in the development of these two bacterial vectors for treatment of cancer. Similarities and differences between the two vectors are discussed.