Diversity and structure of microcrustacean assemblages (Cladocera and Copepoda) and limnological variability in perennial and intermittent pools in a semi-arid region, Bahia, Brazil

Temporary wetlands undergo recurrent drought due to the scarcity of water, which disrupts the hydrological connectivity with adjacent aquatic systems. However, some environments retain water for longer periods, allowing greater persistence of the community. The current study evaluated differences in the microcrustacean assemblages and limnological variability between perennial and intermittent pools in a semi-arid region of Brazil. The abiotic features (water temperature, pH, total alkalinity, electrical conductivity and depth) of intermittent pools were affected more than perennial pools due to loss of water volume. This may have contributed to a higher average richness and diversity index in some intermittent pools and differences in the structure of the assemblages. The lowest species richness and diversity were recorded where physical factors, such as a large quantity of suspended solids and variability in the electrical conductivity of the water and pH, make the environment unsuitable for these organisms. These results suggest that community development in intermittent pools is interrupted by the dry season; when the water returns, due to rainfall or rising groundwater, each pond undergoes a different process of colonization. In these circumstances, the biological importance of temporary aquatic environments is clear, since such pools provide shelters and have an important role in the maintenance of the regional diversity of aquatic environments.

Structure-based drug design studies of the interactions ofent-kaurane diterpenes derived from Wedelia paludosa with the Plasmodium falciparumsarco/endoplasmic reticulum Ca2+-ATPase PfATP6

Malaria is responsible for more deaths around the world than any other parasitic disease. Due to the emergence of strains that are resistant to the current chemotherapeutic antimalarial arsenal, the search for new antimalarial drugs remains urgent though hampered by a lack of knowledge regarding the molecular mechanisms of artemisinin resistance. Semisynthetic compounds derived from diterpenes from the medicinal plant Wedelia paludosawere tested in silico against the Plasmodium falciparumCa2+-ATPase, PfATP6. This protein was constructed by comparative modelling using the three-dimensional structure of a homologous protein, 1IWO, as a scaffold. Compound 21 showed the best docking scores, indicating a better interaction with PfATP6 than that of thapsigargin, the natural inhibitor. Inhibition of PfATP6 by diterpene compounds could promote a change in calcium homeostasis, leading to parasite death. These data suggest PfATP6 as a potential target for the antimalarial ent-kaurane diterpenes.

Local distribution of blackfly (Diptera, Simuliidae) larvae in two adjacent streams: the role of water current velocity in the diversity of blackfly larvae

This study aimed to evaluate the influence of water velocity speed on the local distribution and taxocenosis structure of blackfly larvae. The larvae were collected from two adjacent streams located in the municipality of Angra dos Reis (RJ): Caputera River and one of its tributaries. Riffle litter patches were sampled randomly using a 30 x 30 cm quadrat. Four blackfly species were found: Simulium incrustatum s. l. Lutz, 1910; Simulium (Inaequalium) sp. ; Simulium pertinax s. l. Kollar, 1832 and Simulium subpallidum s. l. Lutz, 1909. Among these species, Simulium pertinax s. l. was clearly associated with higher water current speeds, while Simulium subpallidum s. l. showed association with lower water velocities, and Simulium (Inaequalium) sp. had a relatively constant distribution along the water current gradient.

Land-use systems affect Archaeal community structure and functional diversity in western Amazon soils

The study of the ecology of soil microbial communities at relevant spatial scales is primordial in the wide Amazon region due to the current land use changes. In this study, the diversity of the Archaea domain (community structure) and ammonia-oxidizing Archaea (richness and community composition) were investigated using molecular biology-based techniques in different land-use systems in western Amazonia, Brazil. Soil samples were collected in two periods with high precipitation (March 2008 and January 2009) from Inceptisols under primary tropical rainforest, secondary forest (5-20 year old), agricultural systems of indigenous people and cattle pasture. Denaturing gradient gel electrophoresis of polymerase chain reaction-amplified DNA (PCR-DGGE) using the 16S rRNA gene as a biomarker showed that archaeal community structures in crops and pasture soils are different from those in primary forest soil, which is more similar to the community structure in secondary forest soil. Sequence analysis of excised DGGE bands indicated the presence of crenarchaeal and euryarchaeal organisms. Based on clone library analysis of the gene coding the subunit of the enzyme ammonia monooxygenase (amoA) of Archaea (306 sequences), the Shannon-Wiener function and Simpson's index showed a greater ammonia-oxidizing archaeal diversity in primary forest soils (H' = 2.1486; D = 0.1366), followed by a lower diversity in soils under pasture (H' = 1.9629; D = 0.1715), crops (H' = 1.4613; D = 0.3309) and secondary forest (H' = 0.8633; D = 0.5405). All cloned inserts were similar to the Crenarchaeota amoA gene clones (identity > 95 %) previously found in soils and sediments and distributed primarily in three major phylogenetic clusters. The findings indicate that agricultural systems of indigenous people and cattle pasture affect the archaeal community structure and diversity of ammonia-oxidizing Archaea in western Amazon soils.

Community structure of vascular plants in treefall gaps and fire-disturbed habitats in the Atlantic rainforest, southern Bahia, Brazil

The effects of disturbances on plant community structure in tropical forests have been widely investigated. However, a majority of these studies examined only woody species, principally trees, whereas the effects of disturbances on the whole assemblage of vascular plants remain largely unexplored. At the present study, all vascular plants < 5m tall were surveyed in four habitats: natural treefall gaps, burned forest, and their adjacent understorey. The burned area differed from the other habitats in terms of species composition. However, species richness and plant density did not differ between burned area and the adjacent understorey, which is in accordance to the succession model that predict a rapid recovery of species richness, but with a different species composition in areas under moderate disturbance. The treefall gaps and the two areas of understorey did not differ among themselves in terms of the number of individuals, number of species, nor in species composition. The absence of differences between the vegetation in treefall gaps and in understorey areas seems to be in agreement with the current idea that the species present in treefall gaps are directly related to the vegetation composition before gap formation. Only minimal differences were observed between the analyses that considered only tree species and those that considered all growth habits. This suggests that the same processes acting on tree species (the best studied group of plants in tropical forests) are also acting on the whole assemblage of vascular plants in these communities.

Structure and function of the selectin ligand PSGL-1

P-selectin glycoprotein ligand-1 (PSGL-1) is a dimeric mucin-like 120-kDa glycoprotein on leukocyte surfaces that binds to P- and L-selectin and promotes cell adhesion in the inflammatory response. The extreme amino terminal extracellular domain of PSGL-1 is critical for these interactions, based on site-directed mutagenesis, blocking monoclonal antibodies, and biochemical analyses. The current hypothesis is that for high affinity interactions with P-selectin, PSGL-1 must contain O-glycans with a core-2 branched motif containing the sialyl Lewis x antigen (NeuAca2®3Galß1®4[Fuca1®3]GlcNAcß1®R). In addition, high affinity interactions require the co-expression of tyrosine sulfate on tyrosine residues near the critical O-glycan structure. This review addresses the biochemical evidence for this hypothesis and the evidence that PSGL-1 is an important in vivo ligand for cell adhesion.

Current trends in the global tourism industry: evidence from the United States

Tourism is one of the largest U.S. industries, serving millions of international and domestic tourists yearly. Tourists visit the U.S. to see natural wonders, cities, historic landmarks, and entertainment venues. Americans seek similar attractions as well as recreation and vacation areas. Tourism competes in the global market, so it is important to understand current trends in the U.S. travel industry. Therefore, this article offers insight into important trends and suggests strategies for policy makers involved in the travel and tourism industry.

The institutional configuration of sport policy in Brazil: organization, evolution and dilemmas

Brazil has become the center of the spotlight of the whole world recently, amongst many other reasons, one of them was because it was chosen to host a series of mega sporting events - Pan American Games in 2007, Confederations Football Cup in 2013, Fifa Football World Cup 2014 Games and 2016 Olympic and Paralympic Games in 2016. However, little is known about the country's administrative governmental structure focused on sport policy. The available studies focus their analysis on the sport policies content, but not on the arrangement of its structural decision-making. The main aim of this article is indeed to describe, based on official documentation, the evolution and the current arrangements of the government responsible for the administrative structure for the planning and implementation of sports policies in Brazil. Thus, we tried to list the main problems arising from the organization of the Brazilian sports' management. These problems are: (1) inappropriate institutional structure in terms of human resources and obstacles to participation by other social actors beyond the officials (parliament and members of the Ministry of Sports) in the sports policy; (2) disarticulation between public institutions generating redundancies and conflicts of jurisdiction due to the poor division of labor between bureaucracy agencies; and (3) inadequate planning proved by the lack of organization of some institutions, and by the lack of assessment and continuity of public policies over time. Therefore, we must emphasize those problems from above, and due to these administrative arrangements, Brazilian sports' policy has big challenges in the sport development in this country, which includes the creation of a national "system" for sports and a priority investment in sport education.

Genetic structure of Neisseria meningitidis serogroup C epidemic strains in South Brazil

In the present study we report the results of an analysis, based on serotyping, multilocus enzyme electrophoresis (MEE), and ribotyping of N. meningitidis serogroup C strains isolated from patients with meningococcal disease (MD) in Rio Grande do Sul (RS) and Santa Catarina (SC) States, Brazil, as the Center of Epidemiology Control of Ministry of Health detected an increasing of MD cases due to this serogroup in the last two years (1992-1993). We have demonstrated that the MD due to N.meningitidis serogroup C strains in RS and SC States occurring in the last 4 years were caused mainly by one clone of strains (ET 40), with isolates indistinguishable by serogroup, serotype, subtype and even by ribotyping. One small number of cases that were not due to an ET 40 strains, represent closely related clones that probably are new lineages generated from the ET 40 clone referred as ET 11A complex. We have also analyzed N.meningitidis serogroup C strains isolated in the greater São Paulo in 1976 as representative of the first post epidemic year in that region. The ribotyping method, as well as MEE, could provide useful information about the clonal characteristics of those isolates and also of strains isolated in south Brazil. The strains from 1976 have more similarity with the actual endemic than epidemic strains, by the ribotyping, sulfonamide sensitivity, and MEE results. In conclusion, serotyping with monoclonal antibodies (C:2b:P1.3), MEE (ET 11 and ET 11A complex), and ribotyping by using ClaI restriction enzyme (Rb2), were useful to characterize these epidemic strains of N.meningitidis related to the increased incidence of MD in different States of south Brazil. It is mostly probable that these N.meningitidis serogroup C strains have poor or no genetic corelation with 1971-1975 epidemic serogroup C strains. The genetic similarity of members of the ET 11 and ET 11A complex were confirmed by the ribotyping method by using three restriction endonucleases.