Biodiversity surrogate groups and conservation priority areas: birds of the Brazilian Cerrado

The choice of surrogates of biodiversity is an important aspect in conservation biology. The quantification of the coincidence in the spatial patterns of species richness and rarity between different groups and the vulnerability of groups are different approaches frequently considered to accomplish this task. However, a more appropriate approach is to verify the efficiency of priority networks selected using information from one group of organisms to capture the biodiversity of other groups. Using a deconstructive approach, the main purposes of this study were to evaluate the performance of some orders and families of birds in the Cerrado biome (a savanna-like biome) as surrogates of other bird groups, in a pairwise analysis, and to investigate the characteristics of these groups that predict the efficiency in representation of other groups. We used biogeographical data on bird orders or families with more than 10 species that occur in the Brazilian Cerrado. The best surrogate group was the Thamnophilidae. Moreover, this group is not the most specious, favouring further survey efforts that are necessary to verify the conservation value of areas at suitable scales. The majority of the species from this family are dependent on forest habitats, one of the characteristics that most influenced representativeness level, probably due to the spatial distribution of these habitats throughout the Brazilian Cerrado. Beta diversity patterns of the different groups also affected representativeness, and our analyses showed that the networks selected by a surrogate group will be more effective in the representation of other groups of species if their patterns of beta diversity (not richness) are correlated.     

Daily variation of melatonin content in the optic lobes of the crab Neohelice granulata

Melatonin is a biogenic amine, known from almost all phyla of living organisms. In vertebrates melatonin is produced rhythmically in the pinealocytes of the pineal gland, relaying information of the environmental light/dark cycle to the organism. With regard to crustaceans only a handful of studies exist that has attempted to identify the presence and possible daily variation of this substance. We set out to investigate whether in the crab Neohelice granulata melatonin was produced in the optic lobes of these animals and underwent rhythmic fluctuations related to the daily light/dark cycle. Our experimental animals were divided into three groups exposed to different photoperiods: normal photoperiod (12L:12D), constant dark (DD), and constant light (LL). The optic lobes were collected every 4 hours over a 24-h period for melatonin quantification by radioimmunoassay (RIA). N. granulata kept under 12 L:12D and DD conditions, showed daily melatonin variations with two peaks of abundance (p<0.05), one during the day and another, more extensive one, at night. Under LL-conditions no significant daily variations were noticeable (p>0.05). These results demonstrate the presence of a daily biphasic fall and rise of melatonin in the eyestalk of N. granulata and suggest that continuous exposure to light inhibits the production of melatonin synthesis.     

Do consecutive flower visits within a crown diminish fruit set in mass‐flowering Hancornia speciosa (Apocynaceae)?

Hancornia speciosa is a self-incompatible, mass-flowering, sphingophilous fruit crop (mangaba) of northeast and central Brazil. The flowers have a precise pollination apparatus, which optimizes pollen transfer between flower and pollinator. While the pollination mechanism avoids self-pollination, mass-flowering promotes geitonogamy. During a flower visit, almost half of the exogenous pollen grains adhering to the proboscis are deposited on the stigma surface. A pollination experiment with a nylon thread simulating six consecutive flower visits within a crown revealed that only the first two flowers visited (positions 1 and 2) are highly likely to set fruit. Super-production of flowers, and consequently obligate low fruit set, seem to be part of the reproductive strategy of the obligate outcrossing plant, Hancornia speciosa.     

Antimicrobial activity of Brazilian copaiba oils obtained from different species of the Copaifera genus

The antimicrobial activity of copaiba oils was tested against Gram-positive and Gram-negative bacteria, yeast, and dermatophytes. Oils obtained from Copaifera martii, Copaifera officinalis, and Copaifera reticulata (collected in the state of Acre) were active against Gram-positive species (Staphylococcus aureus, methicillin-resistant S. aureus, Staphylococcus epidermidis, Bacillus subtilis, and Enterococcus faecalis) with minimum inhibitory concentrations ranging from 31.3-62.5 microg/ml. The oils showed bactericidal activity, decreasing the viability of these Gram-positive bacteria within 3 h. Moderate activity was observed against dermatophyte fungi (Trichophyton rubrum and Microsporum canis). The oils showed no activity against Gram-negative bacteria and yeast. Scannning electron microscopy of S. aureus treated with resin oil from C. martii revealed lysis of the bacteria, causing cellular agglomerates. Transmission electron microscopy revealed disruption and damage to the cell wall, resulting in the release of cytoplasmic compounds, alterations in morphology, and a decrease in cell volume, indicating that copaiba oil may affect the cell wall.     

Scale‐dependent responses to forest cover displayed by frugivore bats

Despite vast evidence of species turnover displayed by Neotropical bat communities in response to forest fragmentation, the exact shape of the relationship between fragment area and abundance for individual bat species is still unclear. Bats’ ample variation in diet, morphology, and movement behaviour can potentially influence species’ perception of the landscape. Thus, studies describing fragment area at a single spatial scale may fail to capture the amount of forest available from the perspective of individual bat species. In the present paper, we study the influence of forest cover on bats inhabiting a fragmented forest in Mexico, focusing on some of the most common frugivore species: Artibeus jamaicensis, Carollia spp. (C. brevicauda/C. perspicillata) and Sturnira spp. (S. lilium/S. ludovici). We quantified forest cover at scales ranging from 50 to 2000 m, and measured the influence of forest cover on bat capture success, a surrogate for abundance. The three species displayed positive and significant scale‐dependent associations with forest cover. Abundance of A. jamaicensis increased with forest cover measured at scales ranging between 500 and 2000 m, while Carollia spp. responded more strongly to variation in forest cover measured at scales 100–500 m. For Sturnira spp., abundance was a function of presence of creeks near mist‐netting sites, and amount of secondary forest present at a 200 m scale. The observed variation in responses to forest cover can be explained in light of interspecific differences in diet, home range, and body size. Our results illustrate a method for measuring the effect of forest fragmentation on mobile species and suggest that changes in abundance in fragmented landscapes emerge from the interaction between species’ traits and landscape structure.     

New insights into the mechanistic action of methyldehydrodieugenol B towards <Emphasis Type="Italic">Leishmania</Emphasis> (L.) <Emphasis Type="Italic">infantum</Emphasis> via a multiplatform based untargeted metabolomics approach

Introduction

Leishmaniasis is a parasitic neglected disease affecting millions of people worldwide. Clinical practice resorts to long and costly treatments with a therapeutic arsenal limited to highly toxic drugs, often associated to adverse side effects. Additionally, resistant strains are reported to be increasing.

Aim

In this work, the mechanistic action of a drug candidate (methydehydrodieugenol B), isolated from twigs of Nectandra leucantha, towards Leishmania infantum was studied by a global metabolomics approach using GC-MS and RPLC-MS platforms.

Method

L. infantum promastigotes were grown in culture medium for 72 h and treated with methydehydrodieugenol B at 58.18 μg.mL-1 concentration; after 48 h treatment, enzyme activity was quenched, cells washed and frozen until analysis. For GC-MS analysis (Fiehn’s method), 1:1 methanol:water extracts were prepared and derivatized with O-methoxyamine in pyridine at room temperature for 90 min, followed by silylation with BSTFA/1% TMCS at 40 °C for 30 min. Pure methanolic extracts were also prepared and analyzed directly by RPLC-MS with a acetonitrile/water mobile phase acidulated with formic acid and gradient elution.

Result

Several amino acids, fatty acids, carbohydrates, and glycerolipids were found as discriminant metabolites, mostly decreased in treated samples. Due to the complexity of the parasite metabolism and the great diversity of altered metabolites, a multi-target mechanism was assigned to the drug candidate, where changes in the cell energy sources and in the lipid composition of the parasite plasma membrane were prominent.

Conclusion

These results contributed to elucidate the broad action of methyldehydrodieugenol B against Leishmania, paving the way in the search of novel alternative therapies.

     

A methodology for elucidating regulatory mechanisms leading to changes in lipid profiles

Introduction

It is difficult to elucidate the metabolic and regulatory factors causing lipidome perturbations.

Objectives

This work simplifies this process.

Methods

A method has been developed to query an online holistic lipid metabolic network (of 7923 metabolites) to extract the pathways that connect the input list of lipids.

Results

The output enables pathway visualisation and the querying of other databases to identify potential regulators. When used to a study a plasma lipidome dataset of polycystic ovary syndrome, 14 enzymes were identified, of which 3 are linked to ELAVL1—an mRNA stabiliser.

Conclusion

This method provides a simplified approach to identifying potential regulators causing lipid-profile perturbations.

     

Synthesis and Biological Evaluation of New Natural Phenolic (2E,4E,6E)‐Octa‐2,4,6‐trienoic Esters

In the present study the esterification of the OH groups of resveratrol, caffeic acid, ferulic acid, and β‐sitosterol with an antioxidant polyconjugated fatty acid, (2E,4E,6E)‐octa‐2,4,6‐trienoic acid, was achieved. As the selective esterification of OH groups of natural compounds can affect their biological activity, a selective esterification of resveratrol and caffeic acid was performed by an enzymatic approach. The new resulting compounds were characterized spectroscopically (FT‐IR, NMR mono, and bidimensional techniques); when necessary the experimental data were integrated by quantum chemical calculations. The antioxidant, anti‐inflammatory and proliferative activity was evaluated. The good results encourage the use of these molecules as antioxidant and/or anti‐inflammatory agents in dermocosmetic application.