Metalloproteomics Approach to Analyze Mercury in Breast Milk and Hair Samples of Lactating Women in Communities of the Amazon Basin,Brazil

Mercury is a potentially toxic element that is present in the environment of the Brazilian Amazon and is responsible for adverse health effects in humans. This study sought to assess possible protein biomarkers of mercury exposure in breast milk samples from lactating women in the Madeira and Negro Rivers in the Brazilian Amazon. The mercury content of hair samples of lactating women was determined, and the proteome of breast milk samples was obtained using two-dimensional electrophoresis after protein precipitation with acetone. Mercury measurements of protein spots obtained via protein fractionation were performed by graphite furnace atomic absorption spectrometry (GFAAS), and it was observed that mercury is linked to proteins with molecular masses in the range of 14–26 kDa. The total mercury concentration was also determined by GFAAS in unprocessed milk, lyophilized milk, and protein pellets, with the purpose of determining the mercury mass balance in relation to the concentration of this element in milk and pellets. Approximately 85 to 97% of mercury present in the lyophilized milk from samples of lactating women of the Madeira River is bound in the protein fraction. From lactating women of the Negro River, approximately 49% of the total mercury is bound in the protein fraction, and a difference of 51% is bound in the lipid fraction.     

Structural basis of phospholipase A2-like myotoxin inhibition by chicoric acid,a novel potent inhibitor of ophidian toxins

Background

Specific compounds found in vegetal species have been demonstrated to be efficient inhibitors of snake toxins, such as phospholipase A₂-like (PLA₂-like) proteins. These particular proteins, present in several species of vipers (Viperidae), induce a severe local myotoxic effect in prey and human victims, and this effect is often not efficiently neutralized by the regular serum therapy. PLA₂-like proteins have been functionally and structurally studied since the early 1990s; however, a comprehensive molecular mechanism was proposed only recently.

Vascularized outer-table calvarial bone flaps

Based on an anatomic study of the vascularization of the calvarium in cadavers, a technique for the transfer of vascularized outer-table calvarial bone has been developed. The outer table of the calvarium receives numerous small perforators from its overlying periosteum. The periosteum is continuous with a distinct fascial layer overlying the temporal aponeurosis which we have termed the innominate fascia. Because of a network of anastomosing vessels from proximal branches of the superficial temporal artery and perforating branches of the deep temporal artery, the outer table of the calvarium can be carried on a pedicle which contains the temporal aponeurosis, innominate fascia, and periosteum. Thirty-seven vascularized outer-table calvarial bone flaps have been performed for a variety of craniofacial reconstructive deformities. Remarkable stability and lack of resorption have led the authors to favor this method of reconstruction particularly in poorly vascularized or previously infected recipient beds.     

New pterocarpanquinones: Synthesis,antineoplasic activity on cultured human malignant cell lines and TNF-α modulation in human PBMC cells

A new pterocarpanquinone (5a) was synthesized through a palladium catalyzed oxyarylation reaction and was transformed, through electrophilic substitution reaction, into derivatives 5b–d. These compounds showed to be active against human leukemic cell lines and human lung cancer cell lines. Even multidrug resistant cells were sensitive to 5a, which presented low toxicity toward peripheral blood mononuclear cells (PBMC) cells and decreased the production of TNF-α by these cells. In the laboratory these pterocarpanquinones were reduced by sodium dithionite in the presence of thiophenol at physiological pH, as NAD(P)H quinone oxidoredutase-1 (NQO1) catalyzed two-electron reduction, and the resulting hydroquinone undergo structural rearrangements, leading to the formation of Michael acceptors, which were intercepted as adducts of thiophenol. These results suggest that these compounds could be activated by bioreduction.     

Phylogeny of Neotropical Seirinae (Collembola,Entomobryidae) based on mitochondrial genomes

Seirinae is one of the most diverse subfamilies of Collembola. To date no detailed phylogeny of Seirinae has been proposed, which leads to difficulties in the understanding of evolutionary patterns regarding this taxon. The main aim of this study is to clarify the phylogenetic relationships within the Neotropical Seirinae, by generating and analysing the mitochondrial genomes of 26 terminal taxa of Entomobryidae, and one species of Paronellidae. Specifically, we first generated Illumina HiSeq 2000 shotgun sequence data from each species, then reconstructed the mitochondrial genome of each species using two methods: MitoZ and MIRA/MITOBim. Using these data, we were able to generate a well-supported phylogeny that combined all the above species as well as three publicly available mitogenomes from other species. Bayesian and maximum likelihood methods were applied using all 13 protein coding genes. In this way, monophyly for the internal groups of Seirinae was obtained based on molecular evidence for the first time, as was the potential validity of three main internal taxa of the subfamily. We furthermore validated that Tyrannoseira is a distinct lineage and propose the elevation of Lepidocyrtinus to genus. Lastly, we anticipate that these newly available mitogenomes will serve as a useful dataset for future studies on the evolution of the Collembola and Hexapoda.     

Effects of collagenase and elastase on the mechanical properties of lung tissue strips

The dynamic stiffness (H), dampingcoefficient (G), and harmonic distortion (k_d)characterizing tissue nonlinearity of lung parenchymal strips fromguinea pigs were assessed before and after treatment with elastase orcollagenase between 0.1 and 3.74 Hz. After digestion, data wereobtained both at the same mean length and at the same mean force of thestrip as before digestion. At the same mean length, G and H decreasedby ~33% after elastase and by ~47% after collagenase treatment.At the same mean force, G and H increased by ~7% after elastase andby ~25% after collagenase treatment. The k_dincreased more after collagenase (40%) than after elastase (20%)treatment. These findings suggest that, after digestion, the fractionof intact fibers decreases, which, at the same mean length, leads to adecrease in moduli. At the same mean force, collagen fibers operate ata higher portion of their stress-strain curve, which results in anincrease in moduli. Also, G and H were coupled so that hysteresivity(G/H) did not change after treatments. However,k_d was decoupled from elasticity and wassensitive to stretching of collagen, which may be of value in detectingstructural alterations in the connective tissue of the lung.

     

Different Effects of Transgenic Maize and Nontransgenic Maize on Nitrogen-Transforming Archaea and Bacteria in Tropical Soils

The composition of the rhizosphere microbiome is a result of interactions between plant roots, soil, and environmental conditions. The impact of genetic variation in plant species on the composition of the root-associated microbiota remains poorly understood. This study assessed the abundances and structures of nitrogen-transforming (ammonia-oxidizing) archaea and bacteria as well as nitrogen-fixing bacteria driven by genetic modification of their maize host plants. The data show that significant changes in the abundances (revealed by quantitative PCR) of ammonia-oxidizing bacterial and archaeal communities occurred as a result of the maize host being genetically modified. In contrast, the structures of the total communities (determined by PCR-denaturing gradient gel electrophoresis) were mainly driven by factors such as soil type and season and not by plant genotype. Thus, the abundances of ammonia-oxidizing bacterial and archaeal communities but not structures of those communities were revealed to be responsive to changes in maize genotype, allowing the suggestion that community abundances should be explored as candidate bioindicators for monitoring the possible impacts of cultivation of genetically modified plants.     

Impact of Replacing Smear Microscopy with Xpert MTB/RIF for Diagnosing Tuberculosis in Brazil: A Stepped-Wedge Cluster-Randomized Trial

BackgroundAbundant evidence on Xpert MTB/RIF accuracy for diagnosing tuberculosis (TB) and rifampicin resistance has been produced, yet there are few data on the population benefit of its programmatic use. We assessed whether the implementation of Xpert MTB/RIF in routine conditions would (1) increase the notification rate of laboratory-confirmed pulmonary TB to the national notification system and (2) reduce the time to TB treatment initiation (primary endpoints).ConclusionsReplacing smear microscopy with Xpert MTB/RIF in Brazil increased confirmation of pulmonary TB. An additional benefit was the accurate detection of rifampicin resistance. However, no increase on overall notification rates was observed, possibly because of high rates of empirical TB treatment.

Trial registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01363765","term_id":"NCT01363765"}}NCT01363765Please see later in the article for the Editors'' Summary     

In silico single strand melting curve: a new approach to identify nucleic acid polymorphisms in Totiviridae

Background

The PCR technique and its variations have been increasingly used in the clinical laboratory and recent advances in this field generated new higher resolution techniques based on nucleic acid denaturation dynamics. The principle of these new molecular tools is based on the comparison of melting profiles, after denaturation of a DNA double strand. Until now, the secondary structure of single-stranded nucleic acids has not been exploited to develop identification systems based on PCR. To test the potential of single-strand RNA denaturation as a new alternative to detect specific nucleic acid variations, sequences from viruses of the Totiviridae family were compared using a new in silico melting curve approach. This family comprises double-stranded RNA virus, with a genome constituted by two ORFs, ORF1 and ORF2, which encodes the capsid/RNA binding proteins and an RNA-dependent RNA polymerase (RdRp), respectively.

Results

A phylogenetic tree based on RdRp amino acid sequences was constructed, and eight monophyletic groups were defined. Alignments of RdRp RNA sequences from each group were screened to identify RNA regions with conserved secondary structure. One region in the second half of ORF2 was identified and individually modeled using the RNAfold tool. Afterwards, each DNA or RNA sequence was denatured in silico using the softwares MELTSIM and RNAheat that generate melting curves considering the denaturation of a double stranded DNA and single stranded RNA, respectively. The same groups identified in the RdRp phylogenetic tree were retrieved by a clustering analysis of the melting curves data obtained from RNAheat. Moreover, the same approach was used to successfully discriminate different variants of Trichomonas vaginalis virus, which was not possible by the visual comparison of the double stranded melting curves generated by MELTSIM.

Conclusion

In silico analysis indicate that ssRNA melting curves are more informative than dsDNA melting curves. Furthermore, conserved RNA structures may be determined from analysis of individuals that are phylogenetically related, and these regions may be used to support the reconstitution of their phylogenetic groups. These findings are a robust basis for the development of in vitro systems to ssRNA melting curves detection.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2105-15-243) contains supplementary material, which is available to authorized users.