Variations on a theme: diversification of cuticular hydrocarbons in a clade of cactophilic Drosophila

<p>Abstract</p> <p>Background</p> <p>We characterized variation and chemical composition of epicuticular hydrocarbons (CHCs) in the seven species of the <it>Drosophila buzzatii </it>cluster with gas chromatography/mass spectrometry. Despite the critical role of CHCs in providing resistance to desiccation and involvement in communication, such as courtship behavior, mating, and aggregation, few studies have investigated how CHC profiles evolve within and between species in a phylogenetic context. We analyzed quantitative differences in CHC profiles in populations of the <it>D. buzzatii </it>species cluster in order to assess the concordance of CHC differentiation with species divergence.</p> <p>Results</p> <p>Thirty-six CHC components were scored in single fly extracts with carbon chain lengths ranging from C₂₉to C₃₉, including methyl-branched alkanes, <it>n</it>-alkenes, and alkadienes. Multivariate analysis of variance revealed that CHC amounts were significantly different among all species and canonical discriminant function (CDF) analysis resolved all species into distinct, non-overlapping groups. Significant intraspecific variation was found in different populations of <it>D. serido </it>suggesting that this taxon is comprised of at least two species. We summarized CHC variation using CDF analysis and mapped the first five CHC canonical variates (CVs) onto an independently derived <it>period </it>(<it>per</it>) gene + chromosome inversion + mtDNA COI gene for each sex. We found that the COI sequences were not phylogenetically informative due to introgression between some species, so only <it>per </it>+ inversion data were used. Positive phylogenetic signal was observed mainly for CV1 when parsimony methods and the test for serial independence (TFSI) were used. These results changed when no outgroup species were included in the analysis and phylogenetic signal was then observed for female CV3 and/or CV4 and male CV4 and CV5. Finally, removal of divergent populations of <it>D. serido </it>significantly increased the amount of phylogenetic signal as up to four out of five CVs then displayed positive phylogenetic signal.</p> <p>Conclusions</p> <p>CHCs were conserved among species while quantitative differences in CHC profiles between populations and species were statistically significant. Most CHCs were species-, population-, and sex-specific. Mapping CHCs onto an independently derived phylogeny revealed that a significant portion of CHC variation was explained by species' systematic affinities indicating phylogenetic conservatism in the evolution of these hydrocarbon arrays, presumptive waterproofing compounds and courtship signals as in many other drosophilid species.</p

Decontamination of water by excimer UV radiation

Water is one of the most important substances on which life depends. However, water may also serve as a medium by which disease is spread to humans, animals, and plants. Therefore, the biological decontamination of this vital substance is of paramount importance. Several methods have been used to decontaminate water and assure its clean supply. Unfortunately, most of these methods use potentially hazardous chemicals, which require proper storage and transport and are not environmentally friendly. Here we present a decontamination method based on the use of UV radiation emitted by the decay of excimers generated by a nonequilibrium discharge operating in the high-pressure regime. We found that at an appropriate wavelength, this type of UV radiation has a devastating effect on micro-organisms

Influence of Fcγ RIIA and MBL polymorphisms on severe acute respiratory syndrome

Polymorphisms of human Fc γ-receptor IIA (FcγRIIA) and mannose-binding lectin (MBL) genes have been associated with susceptibility to or severity of some infectious diseases. In order to investigate whether these genetic factors might influence susceptibility to infection with the severe acute respiratory syndrome-associated coronavirus (SARS-Cov) as well as the course and severity of the infection, we evaluated polymorphisms of FcγRIIA and MBL genes in DNA samples from a group of approximately 180 people from Hong Kong who were infected with SARS-Cov. These included 132 patients who had moderate course of SARS infection (home subgroup), 26 patients with a severe course requiring treatment in an intensive care ward (ICU subgroup) and a subgroup of 22 patients who died from SARS (deceased subgroup). A total of 200 normal blood donors from the same region were used as controls. A significant association was found between the FcγRIIA-R/R131 genotype and a severe course of SARS, with higher frequency of homozygosity for FcγRIIA-R/R131 in the ICU subgroup of SARS patients when compared with controls (P = 0.03; odds ratio: 3.2; 95% confidence interval: 1.1-9.1). In comparison with controls, a significant difference in linear trend distribution of FcγRIIA genotypes was seen among the severe SARS patients (ICU and deceased subgroups) without co-morbidity, and the incidence of FcγRIIA-H/H131 was lower in these patients as well. There were no significant differences in MBL genotypes and allele frequencies among SARS patients and controls. The study reveals that in addition to age and co-morbidity, FcγRIIA polymorphism of individuals may also influence outcome after infection with the SARS-Cov. © 2005 Blackwell Publishing Ltd.link_to_subscribed_fulltex

Avaliação do risco de quedas em idosos atendidos em Unidade Básica de Saúde

A população mundial vem envelhecendo de forma abrupta, o que representa um grande desafio para os órgãos competentes que, por sua vez, necessitam de novas políticas públicas de saúde, inclusive na prevenção de quedas. Este estudo objetivou avaliar o risco de quedas em idosos. Trata-se de um estudo epidemiológico de corte transversal com abordagem quantitativa, realizado em uma unidade de saúde da família. A amostra foi composta por 150 idosos avaliados de janeiro a abril de 2009. Para a coleta de dados, utilizou-se o Fall Risk Score, que foi analisado através do SPSS 17.0. Dos idosos avaliados 58,8% não sofreram quedas, sendo que, dos idosos que caíram (63 idosos), 71,4% sofreram de 1 a 2 quedas, citando como principal causa intrínseca a tontura/vertigem, enquanto que a extrínseca foi pisos escorregadios ou molhados. Conclui-se, portanto, que é de grande relevância avaliar o risco de quedas em idosos, para que se medidas preventivas sejam tomadas, com o objetivo de maximizar a qualidade de vida