Abstract: The present report continues to focus on the broadening application of plant extracts for metallic corrosion control and reports on the inhibiting effect of the Aniba rosaeodora alkaloidic extract on the corrosion of C38 steel in 1 M hydrochloric acid. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were applied to study the metal corrosion behavior in the absence and presence of inhibitor. Studies on the phytochemical constituents were established to determine the active(s) molecule(s). XPS was also carried out to establish the mechanism of corrosion inhibition of the active molecule of C38 steel in acid solution. The inhibitor extract acted as an efficient corrosion inhibitor in 1 M HCl. The experimental data obtained from EIS method show a frequency distribution and therefore a modelling element with frequency dispersion behaviour, a constant phase element (CPEα, Q) has been used. Graphical methods are illustrated by synthetic data to determine the parameter of CPE (α, Q). Polarization studies showed that the Aniba rosaeodora alkaloidic extract was a mixed-type inhibitor and its inhibition efficiency increased with the inhibitor concentration. Studies on the phytochemical constituents of the total alkaloids extract shows that it contains the anibine as the major alkaloid. The results obtained from the electrochemical study have clearly showed that the inhibition efficiency of the total extract was due to the presence of anibine. The XPS studies showed the formation of inhibitor layer containing the Aniba rosaeodora alkaloidic extract and the anibine molecules. © 2014 Elsevier Ltd. All rights reserved.

Abstract: The study of decay resistance in wood is of interest for wood end-users but also for the global carbon balance since wood biodegradation is a key driver of forest ecosystem functioning through its impacts on carbon and nutrient cycling. We studied the density and wood extractive contents in order to understand decay resistance against soil microflora after 90 days exposure of sapwood and heartwood from three Neotropical wood species known for their decay resistance: Bocoa prouacensis, Vouacapoua americana, Inga alba. Decay resistance was correlated with density more than wood extractive content. The results highlighted different decay resistance strategies. In B. prouacensis, both sapwood and heartwood were highly resistant due to the high density and high content of antifungal wood extractives. In V. americana heartwood, decay resistance was due to the high synergistic-acting wood extractive content. Conversely, with the least dense wood species I. alba, we found that decay resistance was due to the antifungal wood extractives synthesized early in the sapwood. In conclusion, we showed that the three wood species with the same level of heartwood decay resistance performance had different decay resistance strategies according to the anatomic and defensive wood traits.

Abstract: Analyses of tree diversity and community composition in tropical rain forests are usually based either on general herbarium data or on a restricted number of botanical plots. Despite their high taxonomic accuracy, both types of data are difficult to extrapolate to landscape scales. Meanwhile, forestry surveys provide quantitative occurrence data on large areas, and are thus increasingly used for landscape-scale analyses of tree diversity. However, the reliability of these approaches has been challenged because of the ambiguity of the common (vernacular) names used by foresters and the complexity of tree taxonomy in those hyper-diverse communities.We developed and tested a novel approach to evaluate taxonomic reliability of forestry surveys and to propagate the resulting uncertainty in the estimates of several diversity indicators (alpha and beta entropy, Fisher-alpha and Sørensen similarity). Our approach is based on Monte-Carlo processes that simulate communities by taking into account the expected accuracy and reliability of common names. We tested this method in French Guiana, on 9 one-hectare plots (4279 trees – DBH. ≥. 10. cm) for which both common names and standardized taxonomic determinations were available. We then applied our method of community simulation on large forestry inventories (560. ha) at the landscape scale and compared the diversity indices obtained for 10 sites with those computed from precise botanical determination situated at the same localities.We found that taxonomic reliability of forestry inventories varied from 22% (species level) to 83% (family level) in this Amazonian region. Indices computed directly with raw forestry data resulted in incorrect values, except for Gini-Simpson beta-diversity. On the contrary, our correction method provides more accurate diversity estimates, highly correlated with botanical measurements, for almost all diversity indices at both regional and local scales. We obtained a robust ranking of sites consistent with those shown by botanical inventories.These results show that (i) forestry inventories represent a significant part of taxonomic information, (ii) the relative diversity of regional sites can be successfully ranked using forestry inventory data using our method and (iii) forestry inventories can valuably contribute to the detection of large-scale diversity patterns when biases are well-controlled and corrected.The tools we developed as R-functions are available in supplementary material and can be adapted with local parameters to be used for forest management and conservation issues in other regional contexts. © 2014 Elsevier B.V.

Abstract: The rise of integrative taxonomy, a multi-criteria approach used in characterizing species, fosters the development of new tools facilitating species delimitation. Mass spectrometric (MS) analysis of venom peptides from venomous animals has previously been demonstrated to be a valid method for identifying species. Here we aimed to develop a rapid chemotaxonomic tool for identifying ants based on venom peptide mass fingerprinting. The study focused on the biodiversity of ponerine ants (Hymenoptera: Formicidae: Ponerinae) in French Guiana. Initial experiments optimized the use of automated matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to determine variations in the mass profiles of ant venoms using several MALDI matrices and additives. Data were then analyzed via a hierarchical cluster analysis to classify the venoms of 17 ant species. In addition, phylogenetic relationships were assessed and were highly correlated with methods using DNA sequencing of the mitochondrial gene cytochrome c oxidase subunit 1. By combining a molecular genetics approach with this chemotaxonomic approach, we were able to improve the accuracy of the taxonomic findings to reveal cryptic ant species within species complexes. This chemotaxonomic tool can therefore contribute to more rapid species identification and more accurate taxonomies. Biological significance: This is the first extensive study concerning the peptide analysis of the venom of both Pachycondyla and Odontomachus ants. We studied the venoms of 17 ant species from French Guiana that permitted us to fine-tune the venom analysis of ponerine ants via MALDI-TOF mass spectrometry. We explored the peptidomes of crude ant venom and demonstrated that venom peptides can be used in the identification of ant species. In addition, the application of this novel chemotaxonomic method combined with a parallel genetic approach using COI sequencing permitted us to reveal the presence of cryptic ants within both the Pachycondyla apicalis and Pachycondyla stigma species complexes. This adds a new dimension to the search for means of exploiting the enormous biodiversity of venomous ants as a source for novel therapeutic drugs or biopesticides. This article is part of a Special Issue entitled: Proteomics of non-model organisms. © 2014 Elsevier B.V.

Abstract: Ants (Hymenoptera: Formicidae) represent a taxonomically diverse group of arthropods comprising nearly 13,000 extant species. Sixteen ant subfamilies have individuals that possess a stinger and use their venom for purposes such as a defence against predators, competitors and microbial pathogens, for predation, as well as for social communication. They exhibit a range of activities including antimicrobial, haemolytic, cytolytic, paralytic, insecticidal and pain-producing pharmacologies. While ant venoms are known to be rich in alkaloids and hydrocarbons, ant venoms rich in peptides are becoming more common, yet remain understudied. Recent advances in mass spectrometry techniques have begun to reveal the true complexity of ant venom peptide composition. In the few venoms explored thus far, most peptide toxins appear to occur as small polycationic linear toxins, with antibacterial properties and insecticidal activity. Unlike other venomous animals, a number of ant venoms also contain a range of homodimeric and heterodimeric peptides with one or two interchain disulfide bonds possessing pore-forming, allergenic and paralytic actions. However, ant venoms seem to have only a small number of monomeric disulfide-linked peptides. The present review details the structure and pharmacology of known ant venom peptide toxins and their potential as a source of novel bioinsecticides and therapeutic agents.