Reconstructing the lionfish invasion: insights into Greater Caribbean biogeography

Aim Lionfish (Pterois volitans and P. miles) are popular ornamental fishes native to the Indo‐Pacific that were introduced into Florida waters and are rapidly spreading and establishing throughout the Western Atlantic (WA). Although unfortunate, this invasion provides an excellent system in which to test hypotheses on conservation biology and marine biogeography. The goals of this study are: (1) to document the geographical extent of P. volitans and P. miles; (2) to determine whether the progression of the lionfish invasion is the result of expansion following the initial introduction event or the consequence of multiple introductions at various WA locations; and (3) to analyse the chronology of the invasion in conjunction with the genetic data in order to provide real‐time assessments of hypotheses of marine biogeography. Location The Greater Caribbean, including the US east coast, Bermuda, the Bahamas and the Caribbean Sea. Methods Mitochondrial control region sequences were obtained from lionfish individuals collected from Bermuda and three Caribbean locations and analysed in conjunction with previously published data from five native and two non‐native locations (US east coast and the Bahamas; a total of six WA locations). Genetic variation within and among groups was quantified, and population structure inferred via spatial analyses of molecular variance, pairwise Φ_ST, exact tests, Mantel tests and haplotype networks. Results Mitochondrial DNA screening of WA lionfish shows that while P. miles is restricted to the northernmost locations (Bermuda and the US east coast), P. volitans is ubiquitous and much more abundant. Invasive populations of P. miles and P. volitans have significantly lower levels of genetic diversity relative to their native counterparts, confirming that their introduction resulted in a strong founder effect. Despite the relative genetic homogeneity across the six WA locations, population structure analyses of P. volitans indicate significant differentiation between the northern (US east coast, the Bahamas and Bermuda) and the Caribbean populations. Main conclusions Our findings suggest that the ubiquity of WA lionfish is the result of dispersal from a single source of introduction in Florida and not of multiple independent introductions across the range. In addition, the progression of the lionfish invasion (as documented from sightings), integrated with the genetic evidence, provides support for five of six major scenarios of connectivity and phylogeographical breaks previously inferred for Caribbean organisms.     

Photosynthetic light and carbon dioxide response of the invasive tree, Vochysia divergens Pohl, to experimental flooding and shading

Vochysia divergens Pohl is considered to be a flood-adapted, light-demanding pioneer species that has been invading grasslands of the Brazilian Pantanal. In these areas, a successful invasion requires an ability to tolerate physiologically wide fluctuations in surface hydrology and shading induced by a dense cover of grasses and other vegetation. We evaluated how flooding and shading affected the photosynthetic performance of V. divergens saplings by measuring light-saturated gas exchange (net photosynthetic rate, P _N; stomatal conductance, g _s), and intercellular CO₂ (P _N/C _i) and photosynthetic photon flux density (P _N/PPFD) response curves over a 61-d field experiment. Shading and flooding reduced significantly light-saturated P _N and g _s and affected multiple aspects of the leaf gas exchange response of V. divergens to variations in PPFD and CO₂. Flooding influenced the physiology of this species more than shading. Given the success of V. divergens at invading and expanding in seasonally flooded areas of the Pantanal, the results were surprising and highlighted the physiological ability of this species to tolerate suboptimal conditions. However, the consistently higher light-saturated P _N and g _s under nonflooded conditions suggested that the invasive success of V. divergens might not be related to its physiological potential during flooding, but to situations, when flooding recedes during the dry season and soil water availability is adequate.     

Photosynthetic terpene hydrocarbon production for fuels and chemicals

Photosynthetic hydrocarbon production bypasses the traditional biomass hydrolysis process and represents the most direct conversion of sunlight energy into the next‐generation biofuels. As a major class of biologically derived hydrocarbons with diverse structures, terpenes are also valuable in producing a variety of fungible bioproducts in addition to the advanced ‘drop‐in’ biofuels. However, it is highly challenging to achieve the efficient redirection of photosynthetic carbon and reductant into terpene biosynthesis. In this review, we discuss four major scientific and technical barriers for photosynthetic terpene production and recent advances to address these constraints. Collectively, photosynthetic terpene production needs to be optimized in a systematic fashion, in which the photosynthesis improvement, the optimization of terpene biosynthesis pathway, the improvement of key enzymes and the enhancement of sink effect through terpene storage or secretion are all important. New advances in synthetic biology also offer a suite of potential tools to design and engineer photosynthetic terpene platforms. The systemic integration of these solutions may lead to ‘disruptive’ technologies to enable biofuels and bioproducts with high efficiency, yield and infrastructure compatibility.     

The MAES process in Italy: Contribution of vegetation science to implementation of European Biodiversity Strategy to 2020

Abstract

Target 2 of the European Biodiversity Strategy to 2020, whose aim was to maintain and restore ecosystems and their services, deals in practical terms with the mapping and assessment of ecosystems and their services, with the development of green infrastructure and with halting the loss of biodiversity at the EU, national, and subnational levels. The aim of this short communication was to show the activities currently being carried out in Italy that are related to this target, focusing on the contribution of vegetation science skills to the national implementation process. In particular, we outline noteworthy inputs in ecosystem mapping, in the assessment of ecosystem conservation status, in the individuation of priorities for the restoration of ecosystems, and in the settingup of an ecological framework to promote green infrastructure. An overview of the process outcomes and their relevance within the national and international contexts is also provided.     

Hit identification of novel heparanase inhibitors by structure- and ligand-based approaches

Heparanase is a key enzyme involved in the dissemination of metastatic cancer cells. In this study a combination of in silico techniques and experimental methods was used to identify new potential inhibitors against this target. A 3D model of heparanase was built from sequence homology and applied to the virtual screening of a library composed of 27 known heparanase inhibitors and a commercial collection of drugs and drug-like compounds. The docking results from this campaign were combined with those obtained from a pharmacophore model recently published based in the same set of chemicals. Compounds were then ranked according to their theoretical binding affinity, and the top-rated commercial drugs were selected for further experimental evaluation.Biophysical methods (NMR and SPR) were applied to assess experimentally the interaction of the selected compounds with heparanase. The binding site was evaluated via competition experiments, using a known inhibitor of heparanase. Three of the selected drugs were found to bind to the active site of the protein and their K_D values were determined. Among them, the antimalarial drug amodiaquine presented affinity towards the protein in the low-micromolar range, and was singled out for a SAR study based on its chemical scaffold. A subset of fourteen 4-arylaminoquinolines from a global set of 249 analogues of amodiaquine was selected based on the application of in silico models, a QSAR solubility prediction model and a chemical diversity analysis. Some of these compounds displayed binding affinities in the micromolar range.     

Arabidopsis plants expressing only the redox‐regulated Rca‐α isoform have constrained photosynthesis and plant growth

Rubisco activase (Rca) facilitates the release of sugar‐phosphate inhibitors from the active sites of Rubisco and thereby plays a central role in initiating and sustaining Rubisco activation. In Arabidopsis, alternative splicing of a single Rca gene results in two Rca isoforms, Rca‐α and Rca‐β. Redox modulation of Rca‐α regulates the function of Rca‐α and Rca‐β acting together to control Rubisco activation. Although Arabidopsis Rca‐α alone less effectively activates Rubisco in vitro, it is not known how CO₂ assimilation and plant growth are impacted. Here, we show that two independent transgenic Arabidopsis lines expressing Rca‐α in the absence of Rca‐β (‘Rca‐α only’ lines) grew more slowly in various light conditions, especially under low light or fluctuating light intensity, and in a short day photoperiod compared to wildtype. Photosynthetic induction was slower in the Rca‐α only lines, and they maintained a lower rate of CO₂ assimilation during both photoperiod types. Our findings suggest Rca oligomers composed of Rca‐α only are less effective in initiating and sustaining the activation of Rubisco than when Rca‐β is also present. Currently there are no examples of any plant species that naturally express Rca‐α only but numerous examples of species expressing Rca‐β only. That Rca‐α exists in most plant species, including many C3 and C4 food and bioenergy crops, implies its presence is adaptive under some circumstances.     

Isolation and characterization of eight polymorphic microsatellite markers for the migratory characiform fish, Salminus brasiliensis

Eight polymorphic microsatellite loci were isolated and characterized for the migratory freshwater fish Salminus brasiliensis (Characiformes) and tested on 67 individuals from nine geographically distant locations along the Paraná Basin. The number of alleles per locus ranged from four to 14, with observed heterozygosity estimates ranging from 0·15 to 0·79.     

Lysine acetylation is a widespread protein modification for diverse proteins in Arabidopsis

Lysine acetylation (LysAc), a form of reversible protein posttranslational modification previously known only for histone regulation in plants, is shown to be widespread in Arabidopsis (Arabidopsis thaliana). Sixty-four Lys modification sites were identified on 57 proteins, which operate in a wide variety of pathways/processes and are located in various cellular compartments. A number of photosynthesis-related proteins are among this group of LysAc proteins, including photosystem II (PSII) subunits, light-harvesting chlorophyll a/b-binding proteins (LHCb), Rubisco large and small subunits, and chloroplastic ATP synthase (β-subunit). Using two-dimensional native green/sodium dodecyl sulfate gels, the loosely PSII-bound LHCb was separated from the LHCb that is tightly bound to PSII and shown to have substantially higher level of LysAc, implying that LysAc may play a role in distributing the LHCb complexes. Several potential LysAc sites were identified on eukaryotic elongation factor-1A (eEF-1A) by liquid chromatography/mass spectrometry and using sequence- and modification-specific antibodies the acetylation of Lys-227 and Lys-306 was established. Lys-306 is contained within a predicted calmodulin-binding sequence and acetylation of Lys-306 strongly inhibited the interactions of eEF-1A synthetic peptides with calmodulin recombinant proteins in vitro. These results suggest that LysAc of eEF-1A may directly affect regulatory properties and localization of the protein within the cell. Overall, these findings reveal the possibility that reversible LysAc may be an important and previously unknown regulatory mechanism of a large number of nonhistone proteins affecting a wide range of pathways and processes in Arabidopsis and likely in all plants.