Autosomal and mtDNA Markers Affirm the Distinctiveness of Lions in West and Central Africa

The evolutionary history of a species is key for understanding the taxonomy and for the design of effective management strategies for species conservation. The knowledge about the phylogenetic position of the lion (Panthera leo) in West/Central Africa is largely based on mitochondrial markers. Previous studies using mtDNA only have shown this region to hold a distinct evolutionary lineage. In addition, anthropogenic factors have led to a strong decline in West/Central African lion numbers, thus, the conservation value of these populations is particularly high. Here, we investigate whether autosomal markers are concordant with previously described phylogeographic patterns, and confirm the unique position of the West/Central African lion. Analysis of 20 microsatellites and 1,454 bp of the mitochondrial DNA in 16 lion populations representing the entire geographic range of the species found congruence in both types of markers, identifying four clusters: 1) West/Central Africa, 2) East Africa, 3) Southern Africa and 4) India. This is not in line with the current taxonomy, as defined by the IUCN, which only recognizes an African and an Asiatic subspecies. There are no indications that genetic diversity in West/Central Africa lions is lower than in either East or Southern Africa, however, given this genetic distinction and the recent declines of lion numbers in this region, we strongly recommend prioritization of conservation projects in West/Central Africa. As the current taxonomic nomenclature does not reflect the evolutionary history of the lion, we suggest that a taxonomic revision of the lion is warranted.     

Genomic Characterization of Novel Circular ssDNA Viruses from Insectivorous Bats in Southern Brazil

Circoviruses are highly prevalent porcine and avian pathogens. In recent years, novel circular ssDNA genomes have recently been detected in a variety of fecal and environmental samples using deep sequencing approaches. In this study the identification of genomes of novel circoviruses and cycloviruses in feces of insectivorous bats is reported. Pan-reactive primers were used targeting the conserved rep region of circoviruses and cycloviruses to screen DNA bat fecal samples. Using this approach, partial rep sequences were detected which formed five phylogenetic groups distributed among the Circovirus and the recently proposed Cyclovirus genera of the Circoviridae. Further analysis using inverse PCR and Sanger sequencing led to the characterization of four new putative members of the family Circoviridae with genome size ranging from 1,608 to 1,790 nt, two inversely arranged ORFs, and canonical nonamer sequences atop a stem loop.     

Provisioning of Game Meat to Rural Communities as a Benefit of Sport Hunting in Zambia

Sport hunting has reportedly multiple benefits to economies and local communities; however, few of these benefits have been quantified. As part of their lease agreements with the Zambia Wildlife Authority, sport hunting operators in Zambia are required to provide annually to local communities free of charge i.e., provision a percentage of the meat obtained through sport hunting. We characterized provisioning of game meat to rural communities by the sport hunting industry in Zambia for three game management areas (GMAs) during 2004–2011. Rural communities located within GMAs where sport hunting occurred received on average > 6,000 kgs per GMA of fresh game meat annually from hunting operators. To assess hunting industry compliance, we also compared the amount of meat expected as per the lease agreements versus observed amounts of meat provisioned from three GMAs during 2007–2009. In seven of eight annual comparisons of these GMAs, provisioning of meat exceeded what was required in the lease agreements. Provisioning occurred throughout the hunting season and peaked during the end of the dry season (September–October) coincident with when rural Zambians are most likely to encounter food shortages. We extrapolated our results across all GMAs and estimated 129,771 kgs of fresh game meat provisioned annually by the sport hunting industry to rural communities in Zambia at an approximate value for the meat alone of >US$600,000 exclusive of distribution costs. During the hunting moratorium (2013–2014), this supply of meat has halted, likely adversely affecting rural communities previously reliant on this food source. Proposed alternatives to sport hunting should consider protein provisioning in addition to other benefits (e.g., employment, community pledges, anti-poaching funds) that rural Zambian communities receive from the sport hunting industry.     

Assessment of Wall Elasticity Variations on Intraluminal Haemodynamics in Descending Aortic Dissections Using a Lumped-Parameter Model

Descending aortic dissection (DAD) is associated with high morbidity and mortality rates. Aortic wall stiffness is a variable often altered in DAD patients and potentially involved in long-term outcome. However, its relevance is still mostly unknown. To gain more detailed knowledge of how wall elasticity (compliance) might influence intraluminal haemodynamics in DAD, a lumped-parameter model was developed based on experimental data from a pulsatile hydraulic circuit and validated for 8 clinical scenarios. Next, the variations of intraluminal pressures and flows were assessed as a function of wall elasticity. In comparison with the most rigid-wall case, an increase in elasticity to physiological values was associated with a decrease in systolic and increase in diastolic pressures of up to 33% and 63% respectively, with a subsequent decrease in the pressure wave amplitude of up to 86%. Moreover, it was related to an increase in multidirectional intraluminal flows and transition of behaviour as 2 parallel vessels towards a vessel with a side-chamber. The model supports the extremely important role of wall elasticity as determinant of intraluminal pressures and flow patterns for DAD, and thus, the relevance of considering it during clinical assessment and computational modelling of the disease.     

Focus on Metabolism: Changes in Whole-Plant Metabolism during the Grain-Filling Stage in Sorghum Grown under Elevated CO2 and Drought

Projections indicate an elevation of the atmospheric CO₂ concentration ([CO₂]) concomitant with an intensification of drought for this century, increasing the challenges to food security. On the one hand, drought is a main environmental factor responsible for decreasing crop productivity and grain quality, especially when occurring during the grain-filling stage. On the other hand, elevated [CO₂] is predicted to mitigate some of the negative effects of drought. Sorghum (Sorghum bicolor) is a C₄ grass that has important economical and nutritional values in many parts of the world. Although the impact of elevated [CO₂] and drought in photosynthesis and growth has been well documented for sorghum, the effects of the combination of these two environmental factors on plant metabolism have yet to be determined. To address this question, sorghum plants (cv BRS 330) were grown and monitored at ambient (400 µmol mol⁻¹) or elevated (800 µmol mol⁻¹) [CO₂] for 120 d and subjected to drought during the grain-filling stage. Leaf photosynthesis, respiration, and stomatal conductance were measured at 90 and 120 d after planting, and plant organs (leaves, culm, roots, prop roots, and grains) were harvested. Finally, biochemical composition and intracellular metabolites were assessed for each organ. As expected, elevated [CO₂] reduced the stomatal conductance, which preserved soil moisture and plant fitness under drought. Interestingly, the whole-plant metabolism was adjusted and protein content in grains was improved by 60% in sorghum grown under elevated [CO₂].Global food demand is projected to increase up to 110% by the middle of this century (Tilman et al., 2011; Alexandratos and Bruinsma, 2012), particularly due to a rise in world population that is likely to plateau at about 9 billion people (Godfray et al., 2010). Additionally, the average concentration of atmospheric CO₂ ([CO₂]) has increased 1.75 µmol mol⁻¹ per year between 1975 and today, reaching 400 µmol mol⁻¹ in April 2015 (NOAA, 2015). According to the A2 emission scenario from the U.S. Environmental Protection Agency, in the absence of explicit climate change policy, atmospheric CO₂ concentrations will reach 800 µmol mol⁻¹ by the end of this century. The increasing atmospheric [CO₂] is resulting in global climate changes, such as reduction in water availability and elevation in temperature. These factors are expected to heavily influence food production in the next years (Godfray and Garnett, 2014; Magrin et al., 2014).Sorghum (Sorghum bicolor) is a C₄ grass, considered a staple food grain for millions of the poorest and most food-insecure people in the semiarid tropics of Africa, Asia, and Central America, serving as an important source of energy, proteins, vitamins, and minerals (Taylor et al., 2006). Moreover, this crop is used for animal feed and as industrial raw material in developed countries such as the United States, which is the main world producer (FAO, 2015). With a fully sequenced genome (Paterson et al., 2009) and over 45,000 accessions representing a large geographic and genetic diversity, sorghum is a good model system in which to study the impact of global climate changes in C₄ grasses.The increase in [CO₂] in the atmosphere, which is the main driver of global climate changes (Meehl et al., 2007), is predicted to boost photosynthesis rates and productivity in a series of C₃ legumes and cereals, mainly due to a decrease in the photorespiration process (Grashoff et al., 1995; Long et al., 2006). On the contrary, due to their capacity to concentrate CO₂ in bundle sheath cells and reduce photorespiration to virtually zero, C₄ plants are unlikely to respond to the elevation of atmospheric [CO₂] (Leakey, 2009). However, even for C₄ plants, elevated [CO₂] can ameliorate the effects caused by drought, maintaining higher photosynthetic rates. This is due to an improvement in the efficiency of water use that is achieved by the reduction in stomatal conductance (Leakey et al., 2004; Markelz et al., 2011).The rate of photosynthesis as well as the redistribution of photoassimilates accumulated in different plant tissues during the day and/or during vegetative growth are crucial to grain development, and later, to its filling (Schnyder, 1993). Due to this relationship, any environmental stress such as drought occurring during the reproductive phase has the potential to result in poor grain filling and losses in yield (Blum et al., 1997). For instance, postanthesis drought can cause up to 30% decrease in yield (Borrell et al., 2000). It is also known that elevated [CO₂], drought, high temperature, and any combinations of these stresses can lead to significant changes in grain composition (Taub et al., 2008; Da Matta et al., 2010; Uprety et al., 2010; Madan et al., 2012), suggesting diverse metabolic alterations and/or adaptations that occur in the plant when it is cultivated in such conditions.Although the impacts of elevated [CO₂] and drought on photosynthesis and the growth of sorghum have been well documented (Conley et al., 2001; Ottman et al., 2001; Wall et al., 2001), no attention has been given to the impact of the combination of these two environmental changes on plant metabolism and composition. Regarding physiology, studies on the growth of sorghum under elevated [CO₂] and drought showed an increase of the net assimilation rate of 23% due to a decrease of 32% in stomatal conductance (Wall et al., 2001). This resulted in sorghum’s ability to use water 17% more efficiently (Conley et al., 2001). An improvement in the final overall biomass under elevated [CO₂] and drought has also been described (Ottman et al., 2001), but without a significant effect in grain yield (Wall et al., 2001).Few studies have been monitoring metabolic pathways in plants under elevated [CO₂] (Li et al., 2008; Aranjuelo et al., 2013) and drought (Silvente et al., 2012; Nam et al., 2015; Wenzel et al., 2015). Furthermore, to our knowledge, there are only two reports in which metabolite profiles or metabolic pathways were investigated under the combination of these two environmental conditions (Sicher and Barnaby, 2012; Zinta et al., 2014). Although it is widely accepted that whole-plant metabolism and composition can impact grain filling and yield, metabolic studies conducted so far have focused on a specific plant organ. For instance, Sicher and Barnaby (2012) analyzed the metabolite profile of leaves from maize (Zea mays) plants that were grown under elevated [CO₂] and drought, but they did not show how those environmental changes could have affected the metabolism of other tissues (e.g. culm and roots) or how they might have influenced the biomass or grain composition.In order to address how the combination of elevated [CO₂] and drought can modify whole-plant metabolism as well as biomass composition in sorghum, this study aimed to (1) evaluate photosynthesis, growth, and yield; (2) underline the differences in biomass composition and primary metabolite profiles among leaves, culm, roots, prop roots, and grains; and (3) determine the effect of elevated [CO₂] and drought on the primary metabolism of each organ.     

Extracellular lipid droplets promote hemozoin crystallization in the gut of the blood fluke Schistosoma mansoni

Hemozoin (Hz) is a heme crystal produced upon hemoglobin digestion as the main mechanism of heme disposal in several hematophagous organisms. Here, we show that, in the helminth Schistosoma mansoni, Hz formation occurs in extracellular lipid droplets (LDs). Transmission electron microscopy of adult worms revealed the presence of numerous electron-lucent round structures similar to LDs in gut lumen, where multicrystalline Hz assemblies were found associated to their surfaces. Female regurgitates promoted Hz formation in vitro in reactions partially inhibited by boiling. Fractionation of regurgitates showed that Hz crystallization activity was essentially concentrated on lower density fractions, which have small amounts of pre-formed Hz crystals, suggesting that hydrophilic-hydrophobic interfaces, and not Hz itself, play a key catalytic role in Hz formation in S. mansoni. Thus, these data demonstrate that LDs present in the gut lumen of S. mansoni support Hz formation possibly by allowing association of heme to the lipid-water interface of these structures.     

Trypanosoma cruzi (Kinetoplastida Trypanosomatidae): ecology of the transmission cycle in the wild environment of the Andean valley of Cochabamba, Bolivia

An active Trypanosoma cruzi transmission cycle maintained by wild rodents in the Andean valleys of Cochabamba Bolivia is described. Wild and domestic Triatoma infestans with 60% infection with T. cruzi were found and was evidenced in 47.5% (rodents) and 26.7% (marsupial) by parasitological and/or serologycal methods. Phyllotis ocilae and the marsupial species Thylamys elegans, are the most important reservoirs followed by Bolomys lactens and Akodon boliviensis. In spite of both genotypes (TCI and TCII) being prevalent in Bolivia, in our study area only T. cruzi I is being transmitted. Our data suggest that wild T. infestans and wild small mammals play an important role in the maintenance of the transmission cycle of T. cruzi. Furthermore, the finding of high prevalence of T. cruzi infection in wild T. infestans point to the risk of the dispersion of Chagas' disease.     

Murine p53 inhibits the function but not the formation of SV40 T antigen hexamers and stimulates T antigen RNA helicase activity

We have characterized the effects of p53 on several biochemical activities of simian virus 40 (SV40) large tumor (T) antigen. While p53 induced a strong inhibition of the T antigen DNA helicase activity, surprisingly, its RNA helicase activity was stimulated. This supports the liklihood that the DNA and RNA helicase activities of T antigen reflect discrete functions. p53 did not significantly affect the ATP-dependent conversion of T antigen monomers to hexamers. However, the ability of these hexamers to assemble on a DNA fragment containing the viral origin was impaired by p53. Thus, these results suggest that p53 inhibits the function but not the formation of T antigen multimers. This conclusion was further supported by the observation that the addition of a purified p53:T antigen complex was as inhihitory as free p53 to the DNA helicase activity of free T antigen. Thus our data indicates that the targets of p53 inhibition are the functional units of T antigen, namely the hexamers.     

Cryptic diversity in the lizard genus Plica (Squamata): phylogenetic diversity and Amazonian biogeography

Intra‐ and interspecific genetic diversity of the lizard species Plica plica (9 localities) and Plica umbra (19 localities) from the Brazilian Amazon was analysed using two mitochondrial (16S rDNA and CO1) and one nuclear (prolactin receptor – PRLR) genes. We generated a maximum‐likelihood and Bayesian hypotheses of phylogenetic relationships, and using the bPTP and ABGD lineage delimiting methods inferred the most likely number of lineages within each species. Both methods delimited five distinct lineages in Plica plica and six lineages within Plica umbra. The nominal subspecies of Plica umbra was comprised of one lineage, while Plica umbra ochrocollaris was comprised of five lineages. In majority of the cases, lineages were restricted to the interfluves of major Amazonian rivers, and different lineages occupied distinct areas of endemism. Phylogenetic relationships of the lineages are largely concordant with the hypothesized formation of the areas of endemism. The geographic structuring of the clades and the delimitation of these clades as distinct lineages suggest the possibility that these lineages represent species. If the observed diversity of lineages within the genus Plica is characteristic of squamate reptiles of the Amazon region, the diversity of squamates is grossly underestimated.