A melissopalynological study of artisanal honey produced in Catamarca (Argentina)

Spores belonging to 43 taxa of pteridophytes were observed from the ambient air of 11 localities in India. It is suggested that pteridophyte spores could be listed among viable particulate air pollutants, especially in the light of the earlier reports regarding their allergenicity.     

Botanical affinity of pollen harvested by Apis mellifera L. in a semi-arid area from Bahia,Brazil

We analysed the botanical composition of pollen harvested by Apis mellifera L. in the Canudos Biological Station, Bahia, Brazil, and the influence of climatic factors on pollen sample composition was assessed. Forty-six pollen types were identified belonging to species occurring in the study area. The family Leguminosae was of significant importance amongst the samples, represented by ten pollen types. Diodia radula, Rhaphiodon echinus, and Mimosa misera pollen types occurred most constantly among the samples. We observed that isolated pollen class characterises samples analysed. It was also observed that pollen type richness is directly linked to rainfall, reflecting the strong influence of this climatic parameter on flowering intensity, and thus on the ability of the bees to obtain food resources.     

Late‐moulting Black‐necked Grebes Podiceps nigricollis show greater body mass in the face of failing food supply

From August to December, thousands of Black‐necked Grebes Podiceps nigricollis concentrate during the flightless moult period in salt ponds in the Odiel Marshes, southern Spain, where they feed on the brine shrimp Artemia parthenogenetica. We predicted that because Black‐necked Grebes moulted in a food‐rich, predator‐free environment, there would be no net loss of body mass caused by the use of fat stored to meet energy needs during remigial feather replacement (as is the case for some other diving waterbirds). However, because the food resource disappears in winter, we predicted that grebes moulting later in the season would put on more body mass prior to moult because of the increasing risk of an Artemia population crash before the moult period is completed. Body mass determinations of thousands of birds captured during 2000–2010 showed that grebes in active wing‐moult showed greater mass with date of capture. Early‐moulting grebes were significantly lighter at all stages than late‐moulting birds. Grebes captured with new feathers post‐moult were significantly lighter than those in moult. This is the first study to support the hypothesis that individual waterbirds adopt different strategies in body mass accumulation according to timing of moult: early‐season grebes were able to acquire an excess of energy over expenditure and accumulate fat stores while moulting. Delayed moulters acquired greater fat stores in advance of moult to contribute to energy expenditure for feather replacement and retained extra stores later, most likely as a bet hedge against the increasing probability of failing food supply and higher thermoregulatory demands late in the season. An alternative hypothesis, that mass change is affected by a trophically transmitted cestode using brine shrimps as an intermediate host and Black‐necked Grebes as final host, was not supported by the data.     

Progress towards eliminating canine rabies: policies and perspectives from Latin America and the Caribbean

Human rabies transmitted by dogs is considered a neglected disease that can be eliminated in Latin America and the Caribbean (LAC) by 2015. The aim of this paper is to discuss canine rabies policies and projections for LAC regarding current strategies for achieving this target and to critically review the political, economic and geographical factors related to the successful elimination of this deadly disease in the context of the difficulties and challenges of the region. The strong political and technical commitment to control rabies in LAC in the 1980s, started with the regional programme coordinated by the Pan American Health Organization. National and subnational programmes involve a range of strategies including mass canine vaccination with more than 51 million doses of canine vaccine produced annually, pre- and post-exposure prophylaxis, improvements in disease diagnosis and intensive surveillance. Rabies incidence in LAC has dramatically declined over the last few decades, with laboratory confirmed dog rabies cases decreasing from approximately 25 000 in 1980 to less than 300 in 2010. Dog-transmitted human rabies cases also decreased from 350 to less than 10 during the same period. Several countries have been declared free of human cases of dog-transmitted rabies, and from the 35 countries in the Americas, there is now only notification of human rabies transmitted by dogs in seven countries (Bolivia, Peru, Honduras, Haiti, Dominican Republic, Guatemala and some states in north and northeast Brazil). Here, we emphasize the importance of the political commitment in the final progression towards disease elimination. The availability of strategies for rabies control, the experience of most countries in the region and the historical ties of solidarity between countries with the support of the scientific community are evidence to affirm that the elimination of dog-transmitted rabies can be achieved in the short term. The final efforts to confront the remaining obstacles, like achieving and sustaining high vaccination coverage in communities that are most impoverished or in remote locations, are faced by countries that struggle to allocate sufficient financial and human resources for rabies control. Continent-wide cooperation is therefore required in the final efforts to secure the free status of remaining countries in the Americas, which is key to the regional elimination of human rabies transmitted by dogs.     

Midgut aminopeptidase N isoforms from Ostrinia nubilalis: Activity characterization and differential binding to Cry1Ab and Cry1Fa proteins from Bacillus thuringiensis

Aminopeptidase N (APN) isoforms from Lepidoptera are known for their involvement in the mode of action of insecticidal Cry proteins from Bacillus thuringiensis. These enzymes belong to a protein family with at least eight different members that are expressed simultaneously in the midgut of lepidopteran larvae. Here, we focus on the characterization of the APNs from Ostrinia nubilalis (OnAPNs) to identify potential Cry receptors. We expressed OnAPNs in insect cells using a baculovirus system and analyzed their enzymatic activity by probing substrate specificity and inhibitor susceptibility. The interaction with Cry1Ab and Cry1Fa proteins (both found in transgenic insect-resistant maize) was evaluated by ligand blot assays and immunocytochemistry. Ligand blots of brush border membrane proteins showed that both Cry proteins bound mainly to a 150 kDa-band, in which OnAPNs were greatly represented. Binding analysis of Cry proteins to the cell-expressed OnAPNs showed that OnAPN1 interacted with both Cry1Ab and Cry1Fa, whereas OnAPN3a and OnAPN8 only bound to Cry1Fa. Two isoforms, OnAPN2 and OnAPN3b, did not interact with any of these two proteins. This work provides the first evidence of a differential role of OnAPN isoforms in the mode of action of Cry proteins in O. nubilalis.     

Voltage-dependent anion channel (VDAC) participates in amyloid beta-induced toxicity and interacts with plasma membrane estrogen receptor α in septal and hippocampal neurons

Voltage-dependent anion channel (VDAC) is a porin known by its role in metabolite transport across mitochondria and participation in apoptotic processes. Although traditionally accepted to be located within mitochondrial outer membrane, some data has also reported its presence at the plasma membrane level where it seems to participate in regulation of normal redox homeostasis and apoptosis. Here, exposure of septal SN56 and hippocampal HT22 cells to specific anti-VDAC antibodies prior to amyloid beta (Aβ) peptide was observed to prevent neurotoxicity. In these cell lines, we identified a VDAC form associated with the plasma membrane that seems to be particularly abundant in caveolae. The two membrane-related isoforms of estrogen receptor α (mERα) (80 and 67 kDa), known in SN56 cells to participate in estrogen-induced neuroprotection against Aβ injury, were also observed to be present in caveolae. Interestingly, we demonstrated for the first time that both VDAC and mERα interact at the plasma membrane of these neurons as well as in microsomal fractions of the corresponding murine septal and hippocampal tissues. These proteins were also shown to associate with caveolin-1, thereby corroborating their presence in caveolar microdomains. Taken together, these results suggest that VDAC-mERα association at the plasma membrane level may participate in the modulation of Aβ-induced cell death.     

New structure–activity relationship studies in a series of N,N-bis(cyclohexanol)amine aryl esters as potent reversers of P-glycoprotein-mediated multidrug resistance (MDR)

As a continuation of previous research on a new series of potent and efficacious P-gp-dependent multidrug resistant (MDR) reversers with a N,N-bis(cyclohexanol)amine scaffold, we have designed and synthesized several analogs by modulation of the two aromatic moieties linked through ester functions to the N,N-bis(cyclohexanol)amine, aiming to optimize activity and to extend structure–activity relationships (SAR) within the series. This scaffold, when esterified with two different aromatic carboxylic acids, gives origin to four geometric isomers (cis/trans, trans/trans, cis/cis and trans/cis).The new compounds were tested on doxorubicin-resistant erythroleukemia K562 cells (K562/DOX) in the pirarubicin uptake assay. Most of them resulted in being potent modulators of the extrusion pump P-gp, showing potency values ([I]_0.5) in the submicromolar and nanomolar range. Of these, compounds 2b, 2c, 3d, 5a–d and 6d, showed excellent efficacy with a α_max close to 1. Selected compounds (2d, 3a, 3b, 5a–d) were further studied to evaluate their doxorubicin cytotoxicity potentiation (RF) on doxorubicin-resistant erythroleukemia K562 cells and were found able to enhance significantly doxorubicin cytotoxicity on K562/DOX cells.The results of both pirarubicin uptake and the cytotoxicity assay, indicate that the new compounds of the series are potent P-gp-mediated MDR reversers. They present a structure with a mix of flexible and rigid moieties, a property that seems critical to allow the molecules to choose the most productive of the several binding modes possible in the transporter recognition site.In particular, compounds 5c and 5d, similar to the already reported analogous isomers 1c and 1d,²⁹ are potent and efficacious modulators of P-gp-dependent MDR and may be promising leads for the development of MDR-reversal drugs.     

Caffeine-containing energy drink improves sprint performance during an international rugby sevens competition

The aim of this study was to determine the effects of a caffeine-containing energy drink on physical performance during a rugby sevens competition. A second purpose was to investigate the post-competition urinary caffeine concentration derived from the energy drink intake. On two non-consecutive days of a friendly tournament, 16 women from the Spanish National rugby sevens Team (mean age and body mass = 23 ± 2 years and 66 ± 7 kg) ingested 3 mg of caffeine per kg of body mass in the form of an energy drink (Fure^®, ProEnergetics) or the same drink without caffeine (placebo). After 60 min for caffeine absorption, participants performed a 15-s maximal jump test, a 6 × 30 m sprint test, and then played three rugby sevens games against another national team. Individual running pace and instantaneous speed during the games were assessed using global positioning satellite (GPS) devices. Urine samples were obtained pre and post-competition. In comparison to the placebo, the ingestion of the energy drink increased muscle power output during the jump series (23.5 ± 10.1 vs. 25.6 ± 11.8 kW, P = 0.05), running pace during the games (87.5 ± 8.3 vs. 95.4 ± 12.7 m/min, P < 0.05), and pace at sprint velocity (4.6 ± 3.3 vs. 6.1 ± 3.4 m/min, P < 0.05). However, the energy drink did not affect maximal running speed during the repeated sprint test (25.0 ± 1.5 vs. 25.0 ± 1.7 km/h). The ingestion of the energy drink resulted in a higher post-competition urine caffeine concentration than the placebo (3.3 ± 0.7 vs. 0.2 ± 0.1 μg/mL; P < 0.05). In summary, 3 mg/kg of caffeine in the form of a commercially available energy drink considerably enhanced physical performance during a women’s rugby sevens competition.     

Acute creatine administration improves mitochondrial membrane potential and protects against pentylenetetrazol-induced seizures

A growing body of evidence indicates that creatine (Cr) exerts beneficial effects on a variety of pathologies where energy metabolism and oxidative stress play an etiological role. However, the benefits of Cr treatment for epileptics are still shrouded in controversy. In the present study, we found that acute Cr treatment (300 mg/kg, p.o.) prevented the increase in electroencephalographic wave amplitude typically elicited by PTZ (30, 45 or 60 mg/kg, i.p.). Cr treatment also increased the latency periods of first myoclonic jerks, lengthened the latency periods of the generalized tonic–clonic seizures and reduced the time spent in the generalized tonic–clonic seizures induced by PTZ (60 mg/kg). Administration of PTZ (all doses) decreased Na⁺, K⁺-ATPase activity as well as adenosine triphosphate (ATP) and adenosine diphosphate levels in the cerebral cortex, but Cr treatment prevented these effects. Cr administration also prevented increases in xanthine oxidase activity, adenosine monophosphate levels, adenosine levels, inosine levels and uric acid levels that normally occur after PTZ treatment (60 mg/kg, i.p.). We also showed that Cr treatment increased the total Cr (Cr + PCr) content, creatine kinase activity and the mitochondrial membrane potential (ΔΨ) in the cerebral cortex. In addition, Cr prevented PTZ-induced mitochondrial dysfunction characterized by decreasing ΔΨ, increasing thiobarbituric acid-reactive substance levels and increasing protein carbonylation. These experimental findings reinforce the idea that mitochondrial dysfunction plays a critical role in models of epileptic seizures and suggest that buffering brain energy levels through Cr treatment may be a promising therapeutic approach for the treatment of this neurological disease.