Abstract: The phenotypic plasticity of plants has been explored as a function of either ontogeny (apparent plasticity) or environment (adaptive plasticity), although few studies have analyzed these factors together. In the present study, we take advantage of the dispersal of Aechmea mertensii bromeliads by Camponotus femoratus or Pachycondyla goeldii ants in shaded and sunny environments, respectively, to quantify ontogenetic changes in morphological, foliar, and functional traits, and to analyze ontogenetic and ant species effects on 14 traits. Most of the morphological (plant height, number of leaves), foliar (leaf thickness, leaf mass area, total water content, trichome density), and functional (leaf δ13C) traits differed as a function of ontogeny. Conversely, only leaf δ15N showed an adaptive phenotypic plasticity. On the other hand, plant width, tank width, longest leaf length, stomatal density, and leaf C concentration showed an adaptation to local environment with ontogeny. The exception was leaf N concentration, which showed no trend at all. Aechmea mertensii did not show an abrupt morphological modification such as in heteroblastic bromeliads, although it was characterized by strong, size-related functional modifications for CO2 acquisition. The adaptive phenotypic variation found between the two ant species indicates the spatially conditioned plasticity of A. mertensii in the context of insect-assisted dispersal. However, ant-mediated effects on phenotypic plasticity in A. mertensii are not obvious because ant species and light environment are confounding variables. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 175, 299–312.

Abstract: Ethnopharmacological relevance:
Field investigations highlighted the use of Psidium acutangulum Mart. ex DC (syn. P. persoonii McVaugh), a small tree used by the Wayana Amerindians in Twenke–Taluhwen and Antecume–Pata, French Guiana, for the treatment of malaria, and administered either orally in the form of a decoction or applied externally over the whole body. This use appears limited to the Wayana cultural group in French Guiana and has never been reported anywhere else. Our goal was to evaluate the antimalarial and anti-inflammatory activities of a P. acutangulum decoction to explain the good reputation of this remedy.
Materials and methods:
Interviews with the Wayana inhabitants of Twenke–Taluhwen and Antecume–Pata were conducted within the TRAMAZ project according to the TRAMIL methodology, which is based on a quantitative and qualitative analysis of medicinal plant uses. A decoction of dried aerial parts of P. acutangulum was prepared in consistency with the Wayana recipe. In vitro antiplasmodial assays were performed on chloroquine-resistant FcB1 ([3H]-hypoxanthine bioassay) and 7G8 (pLDH bioassay) P. falciparum strains and on chloroquine sensitive NF54 ([3H]-hypoxanthine bioassay) P. falciparum strain. In vitro anti-inflammatory activity (IL-1β, IL-6, IL-8, TNFα) was evaluated on LPS-stimulated human PBMC and NO secretion inhibition was measured on LPS stimulated RAW murine macrophages. Cytotoxicity of the decoction was measured on L6 mammalian cells, PBMCs, and RAW cells. A preliminary evaluation of the in vivo antimalarial activity of the decoction, administered orally twice daily, was assessed by the classical four-day suppressive test against P. berghei NK65 in mice.
Results:
The decoction displayed a good antiplasmodial activity in vitro against the three tested strains, regardless to the bioassay used, with IC50 values of 3.3 µg/mL and 10.3 µg/mL against P. falciparum FcB1 and NF54, respectively and 19.0 µg/mL against P. falciparum 7G8. It also exhibited significant anti-inflammatory activity in vitro in a dose dependent manner. At a concentration of 50 µg/mL, the decoction inhibited the secretion of the following pro-inflammatory cytokines: TNFα (−18%), IL-1β (−58%), IL-6 (−32%), IL-8 (−21%). It also exhibited a mild NO secretion inhibition (−13%) at the same concentration. The decoction was non-cytotoxic against L6 cells (IC50>100 µg/mL), RAW cells and PBMC. In vivo, 150 µL of the decoction given orally twice a day (equivalent to 350 mg/kg/day of dried extract) inhibited 39.7% average parasite growth, with more than 50% of inhibition in three mice over five. The absence of response for the two remaining mice, however, induced a strong standard deviation.
Conclusions:
This study highlighted the in vitro antiplasmodial activity of the decoction of P. acutangulum aerial parts, used by Wayana Amerindians from the Upper-Maroni in French Guiana in case of malaria. Its antioxidant and anti-inflammatory potential, which may help to explain its use against this disease, was demonstrated using models of artificially stimulated cells.

Abstract: This study examined whether the antidermatophytic activity of essential oils (EOs) can be used as an indicator for the discovery of active natural products against Leishmania amazonensis. The aerial parts of seven plants were hydrodistilled. Using broth microdilution techniques, the obtained EOs were tested against three strains of dermatophytes (Trichophyton mentagrophytes, Microsporum gypseum and Microsporum canis). To compare the EOs antifungal and antiparasitic effects, the EOs activities against axenic amastigotes of L. amazonensis were concurrently evaluated. For the most promising EOs, their antileishmanial activities against parasites infecting peritoneal macrophages of BALB/c mice were measured. The most interesting antifungal candidates were the EOs from Cymbopogon citratus, Otacanthus azureus and Protium heptaphyllum, whereas O. azureus, Piper hispidum and P. heptaphyllum EOs exhibited the lowest 50% inhibitory concentration (IC50) values against axenic amastigotes, thus revealing a certain correspondence between both activities. The P. hispidum EO was identified as the most promising product in the results from the infected macrophages model (IC50: 4.7 μg/mL, safety index: 8). The most abundant compounds found in this EO were sesquiterpenes, notably curzerene and furanodiene. Eventually, the evaluation of the antidermatophytic activity of EOs appears to be an efficient method for identifying new potential drugs for the treatment of L. amazonensis.

Abstract: Quantifying the spatio-temporal distribution of arthropods in tropical rainforests represents a first step towards scrutinizing the global distribution of biodiversity on Earth. To date most studies have focused on narrow taxonomic groups or lack a design that allows partitioning of the components of diversity. Here, we consider an exceptionally large dataset (113,952 individuals representing 5,858 species), obtained from the San Lorenzo forest in Panama, where the phylogenetic breadth of arthropod taxa was surveyed using 14 protocols targeting the soil, litter, understory, lower and upper canopy habitats, replicated across seasons in 2003 and 2004. This dataset is used to explore the relative influence of horizontal, vertical and seasonal drivers of arthropod distribution in this forest. We considered arthropod abundance, observed and estimated species richness, additive decomposition of species richness, multiplicative partitioning of species diversity, variation in species composition, species turnover and guild structure as components of diversity. At the scale of our study (2km of distance, 40m in height and 400 days), the effects related to the vertical and seasonal dimensions were most important. Most adult arthropods were collected from the soil/litter or the upper canopy and species richness was highest in the canopy. We compared the distribution of arthropods and trees within our study system. Effects related to the seasonal dimension were stronger for arthropods than for trees. We conclude that: (1) models of beta diversity developed for tropical trees are unlikely to be applicable to tropical arthropods; (2) it is imperative that estimates of global biodiversity derived from mass collecting of arthropods in tropical rainforests embrace the strong vertical and seasonal partitioning observed here; and (3) given the high species turnover observed between seasons, global climate change may have severe consequences for rainforest arthropods.

Abstract: In members of the cricket subfamily Eneopterinae (Orthoptera, Grylloidea), songs with powerful high-frequency (HF) harmonics have evolved, which likely represents a distinctive acoustic adaptation. In this study, we analysed or reanalysed the songs of the three eneopterine genera present in the Neotropics to evaluate whether they also possess high-amplitude HF components. We present new data and combine several lines of evidence to interpret or reinterpret the calling signals of a representative species for each genus. We used new recordings in order to detect and analyse potential HF components of the songs. Stridulatory files were measured, and stridulation was studied using high-speed video recordings. The results suggest that all eneopterine genera from the Neotropics use HFs to communicate, based on the rich harmonic content of their songs. Strikingly, the Neotropical eneopterines possess high dominant frequencies, recalling the patterns observed in the tribe Lebinthini, the most speciose tribe of the subfamily distributed in the Western Pacific region and in Southeast Asia: Ligypterus and Ponca show dominant harmonic peaks, whereas Eneoptera possesses unique features. The three species under study, however, deal differently with HFs.