Acute schistosomiasis: a risk underestimated by travelers and a diagnosis frequently missed by general practitioners-a cluster analysis of 42 travelers.

BACKGROUND: In 2011, a patient was admitted to our hospital with acute schistosomiasis after having returned from Madagascar and having bathed at the Lily waterfalls. On the basis of this patient's indication, infection was suspected in 41 other subjects. This study investigated (1) the knowledge of the travelers about the risks of schistosomiasis and their related behavior to evaluate the appropriateness of prevention messages and (2) the diagnostic workup of symptomatic travelers by general practitioners to evaluate medical care of travelers with a history of freshwater exposure in tropical areas. METHODS: A questionnaire was sent to the 42 travelers with potential exposure to schistosomiasis. It focused on pre-travel knowledge of the disease, bathing conditions, clinical presentation, first suspected diagnosis, and treatment. RESULTS: Of the 42 questionnaires, 40 (95%) were returned, among which 37 travelers (92%) reported an exposure to freshwater, and 18 (45%) were aware of the risk of schistosomiasis. Among these latter subjects, 16 (89%) still reported an exposure to freshwater. Serology was positive in 28 (78%) of 36 exposed subjects at least 3 months after exposure. Of the 28 infected travelers, 23 (82%) exhibited symptoms and 16 (70%) consulted their general practitioner before the information about the outbreak had spread, but none of these patients had a serology for schistosomiasis done during the first consultation. CONCLUSIONS: The usual prevention message of avoiding freshwater contact when traveling in tropical regions had no impact on the behavior of these travelers, who still went swimming at the Lily waterfalls. This prevention message should, therefore, be either modified or abandoned. The clinical presentation of acute schistosomiasis is often misleading. General practitioners should at least request an eosinophil count, when confronted with a returning traveler with fever. If eosinophilia is detected, it should prompt the search for a parasitic disease.

Design and implementation of FPGA-based LQ control of active magnetic bearings

The need for high performance, high precision, and energy saving in rotating machinery demands an alternative solution to traditional bearings. Because of the contactless operation principle, the rotating machines employing active magnetic bearings (AMBs) provide many advantages over the traditional ones. The advantages such as contamination-free operation, low maintenance costs, high rotational speeds, low parasitic losses, programmable stiffness and damping, and vibration insulation come at expense of high cost, and complex technical solution. All these properties make the use of AMBs appropriate primarily for specific and highly demanding applications. High performance and high precision control requires model-based control methods and accurate models of the flexible rotor. In turn, complex models lead to high-order controllers and feature considerable computational burden. Fortunately, in the last few years the advancements in signal processing devices provide new perspective on the real-time control of AMBs. The design and the real-time digital implementation of the high-order LQ controllers, which focus on fast execution times, are the subjects of this work. In particular, the control design and implementation in the field programmable gate array (FPGA) circuits are investigated. The optimal design is guided by the physical constraints of the system for selecting the optimal weighting matrices. The plant model is complemented by augmenting appropriate disturbance models. The compensation of the force-field nonlinearities is proposed for decreasing the uncertainty of the actuator. A disturbance-observer-based unbalance compensation for canceling the magnetic force vibrations or vibrations in the measured positions is presented. The theoretical studies are verified by the practical experiments utilizing a custom-built laboratory test rig. The test rig uses a prototyping control platform developed in the scope of this work. To sum up, the work makes a step in the direction of an embedded single-chip FPGA-based controller of AMBs.

Investigation of defect formation and electronic transport in microcrystalline silicon deposited by hot-wire CVD

We have investigated doped and undoped layers of microcrystalline silicon prepared by hot-wire chemical vapour deposition optically, electrically and by means of transmission electron microscopy. Besides needle-like crystals grown perpendicular to the substrate's surface, all of the layers contained a noncrystalline phase with a volume fraction between 4% and 25%. A high oxygen content of several per cent in the porous phase was detected by electron energy loss spectrometry. Deep-level transient spectroscopy of the crystals suggests that the concentration of electrically active defects is less than 1% of the undoped background concentration of typically 10^17 cm -3. Frequency-dependent measurements of the conductance and capacitance perpendicular to the substrate surface showed that a hopping process takes place within the noncrystalline phase parallel to the conduction in the crystals. The parasitic contribution to the electrical circuit arising from the porous phase is believed to be an important loss mechanism in the output of a pin-structured photovoltaic solar cell deposited by hot-wire CVD.

Distribution and risk factors for Plasmodium and helminth co-infections: a cross-sectional survey among children in Bagamoyo district, coastal region of Tanzania.

BACKGROUND: Plasmodium and soil transmitted helminth infections (STH) are a major public health problem, particularly among children. There are conflicting findings on potential association between these two parasites. This study investigated the Plasmodium and helminth co-infections among children aged 2 months to 9 years living in Bagamoyo district, coastal region of Tanzania. METHODS: A community-based cross-sectional survey was conducted among 1033 children. Stool, urine and blood samples were examined using a broad set of quality controlled diagnostic methods for common STH (Ascaris lumbricoides, hookworm, Strongyloides stercoralis, Enterobius vermicularis, Trichuris trichura), schistosoma species and Wuchereria bancrofti. Blood slides and malaria rapid diagnostic tests (mRDTs) were utilized for Plasmodium diagnosis. RESULTS: Out of 992 children analyzed, the prevalence of Plasmodium infection was 13% (130/992), helminth 28.5% (283/992); 5% (50/992) had co-infection with Plasmodium and helminth. The prevalence rate of Plasmodium, specific STH and co-infections increased significantly with age (p < 0.001), with older children mostly affected except for S. stercoralis monoinfection and co-infections. Spatial variations of co-infection prevalence were observed between and within villages. There was a trend for STH infections to be associated with Plasmodium infection [OR adjusted for age group 1.4, 95% CI (1.0-2.1)], which was more marked for S. stercoralis (OR = 2.2, 95% CI (1.1-4.3). Age and not schooling were risk factors for Plasmodium and STH co-infection. CONCLUSION: The findings suggest that STH and Plasmodium infections tend to occur in the same children, with increasing prevalence of co-infection with age. This calls for an integrated approach such as using mass chemotherapy with dual effect (e.g., ivermectin) coupled with improved housing, sanitation and hygiene for the control of both parasitic infections.

Learning-induced gene expression in the heads of two Nasonia species that differ in long-term memory formation.

BACKGROUND: Cellular processes underlying memory formation are evolutionary conserved, but natural variation in memory dynamics between animal species or populations is common. The genetic basis of this fascinating phenomenon is poorly understood. Closely related species of Nasonia parasitic wasps differ in long-term memory (LTM) formation: N. vitripennis will form transcription-dependent LTM after a single conditioning trial, whereas the closely-related species N. giraulti will not. Genes that were differentially expressed (DE) after conditioning in N. vitripennis, but not in N. giraulti, were identified as candidate genes that may regulate LTM formation. RESULTS: RNA was collected from heads of both species before and immediately, 4 or 24 hours after conditioning, with 3 replicates per time point. It was sequenced strand-specifically, which allows distinguishing sense from antisense transcripts and improves the quality of expression analyses. We determined conditioning-induced DE compared to naïve controls for both species. These expression patterns were then analysed with GO enrichment analyses for each species and time point, which demonstrated an enrichment of signalling-related genes immediately after conditioning in N. vitripennis only. Analyses of known LTM genes and genes with an opposing expression pattern between the two species revealed additional candidate genes for the difference in LTM formation. These include genes from various signalling cascades, including several members of the Ras and PI3 kinase signalling pathways, and glutamate receptors. Interestingly, several other known LTM genes were exclusively differentially expressed in N. giraulti, which may indicate an LTM-inhibitory mechanism. Among the DE transcripts were also antisense transcripts. Furthermore, antisense transcripts aligning to a number of known memory genes were detected, which may have a role in regulating these genes. CONCLUSION: This study is the first to describe and compare expression patterns of both protein-coding and antisense transcripts, at different time points after conditioning, of two closely related animal species that differ in LTM formation. Several candidate genes that may regulate differences in LTM have been identified. This transcriptome analysis is a valuable resource for future in-depth studies to elucidate the role of candidate genes and antisense transcription in natural variation in LTM formation.

Three-step pathway engineering results in more incidence rate and higher emission of nerolidol and improved attraction of Diadegma semiclausum

The concentration and ratio of terpenoids in the headspace volatile blend of plants have a fundamental role in the communication of plants and insects. The sesquiterpene (E)-nerolidol is one of the important volatiles with effect on beneficial carnivores for biologic pest management in the field. To optimize de novo biosynthesis and reliable and uniform emission of (E)-nerolidol, we engineered different steps of the (E)-nerolidol biosynthesis pathway in Arabidopsis thaliana. Introduction of a mitochondrial nerolidol synthase gene mediates de novo emission of (E)-nerolidol and linalool. Co-expression of the mitochondrial FPS1 and cytosolic HMGR1 increased the number of emitting transgenic plants (incidence rate) and the emission rate of both volatiles. No association between the emission rate of transgenic volatiles and their growth inhibitory effect could be established. (E)-Nerolidol was to a large extent metabolized to non-volatile conjugates.

The Intestinal Microbiota Contributes to the Ability of Helminths to Modulate Allergic Inflammation.

Intestinal helminths are potent regulators of their host's immune system and can ameliorate inflammatory diseases such as allergic asthma. In the present study we have assessed whether this anti-inflammatory activity was purely intrinsic to helminths, or whether it also involved crosstalk with the local microbiota. We report that chronic infection with the murine helminth Heligmosomoides polygyrus bakeri (Hpb) altered the intestinal habitat, allowing increased short chain fatty acid (SCFA) production. Transfer of the Hpb-modified microbiota alone was sufficient to mediate protection against allergic asthma. The helminth-induced anti-inflammatory cytokine secretion and regulatory T cell suppressor activity that mediated the protection required the G protein-coupled receptor (GPR)-41. A similar alteration in the metabolic potential of intestinal bacterial communities was observed with diverse parasitic and host species, suggesting that this represents an evolutionary conserved mechanism of host-microbe-helminth interactions.

Genomic insights into the Ixodes scapularis tick vector of Lyme disease.

Ticks transmit more pathogens to humans and animals than any other arthropod. We describe the 2.1 Gbp nuclear genome of the tick, Ixodes scapularis (Say), which vectors pathogens that cause Lyme disease, human granulocytic anaplasmosis, babesiosis and other diseases. The large genome reflects accumulation of repetitive DNA, new lineages of retro-transposons, and gene architecture patterns resembling ancient metazoans rather than pancrustaceans. Annotation of scaffolds representing ∼57% of the genome, reveals 20,486 protein-coding genes and expansions of gene families associated with tick-host interactions. We report insights from genome analyses into parasitic processes unique to ticks, including host 'questing', prolonged feeding, cuticle synthesis, blood meal concentration, novel methods of haemoglobin digestion, haem detoxification, vitellogenesis and prolonged off-host survival. We identify proteins associated with the agent of human granulocytic anaplasmosis, an emerging disease, and the encephalitis-causing Langat virus, and a population structure correlated to life-history traits and transmission of the Lyme disease agent.

Phenotipic comparison of clinical and plant beneficial strains of Pantoea agglomerans

Certain strains of Pantoea are used as biocontrol agents for the suppression of plant diseases. However, their commercial registration is hampered in some countries because of biosafety concerns. This study compares clinical and plant-beneficial strains of P. agglomerans and related species using a phenotypic analysis approach in which plant-beneficial effects, adverse effects in nematode models, and toxicity were evaluated. Plant-beneficial effects were determined as the inhibition of apple fruit infection by Penicillium expansum and apple flower infection by Erwinia amylovora. Clinical strains had no general inhibitory activity against infection by the fungal or bacterial plant pathogens, as only one clinical strain inhibited P. expansum and three inhibited E. amylovora. By contrast, all biocontrol strains showed activity against at least one of the phytopathogens, and three strains were active against both. The adverse effects in animals were evaluated in the plant-parasitic nematode Meloidogyne javanica and the bacterial-feeding nematode Caenorhabditis elegans. Both models indicated adverse effects of the two clinical strains but not of any of the plant-beneficial strains. Toxicity was evaluated by means of hemolytic activity in blood, and genotoxicity with the Ames test. None of the strains, whether clinical or plant-beneficial, showed any evidence of toxicity

Enzymes of yeast polyphosphate metabolism: structure, enzymology and biological roles.

Inorganic polyphosphate (polyP) is found in all living organisms. The known polyP functions in eukaryotes range from osmoregulation and virulence in parasitic protozoa to modulating blood coagulation, inflammation, bone mineralization and cellular signalling in mammals. However mechanisms of regulation and even the identity of involved proteins in many cases remain obscure. Most of the insights obtained so far stem from studies in the yeast Saccharomyces cerevisiae. Here, we provide a short overview of the properties and functions of known yeast polyP metabolism enzymes and discuss future directions for polyP research.

Quimioterapia da doença de Chagas: estado da arte e perspectivas no desenvolvimento de novos fármacos

Neglected diseases are a major global cause of illness, long-term disability and death. Chagas' disease is a parasitic infection widely distributed throughout Latin America, with devastating consequences in terms of human morbidity and mortality. The existing drug therapy suffers from a combination of drawbacks including poor efficacy, resistance and serious side effects. In 2009, we celebrate the 100th anniversary of the discovery of Chagas' disease, facing the challenges of developing new, safe and effective drugs for the treatment of this disease. This brief review attempts to highlight the state of the art, limitations and perspectives of Chagas' disease drug development.

In vitro trypanocidal evaluation of pinane derivatives from essential oils of ripe fruits from Schinus terebinthifolius Raddi (Anacardiaceae)

Essential oils of ripe fruits from Schinus terebinthifolius (Anacardiaceae), obtained using a pilot extractor and a Clevenger apparatus were chemically characterized. Due the high amount of (-)- α-pinene in both oils, this monoterpene was tested against the protozoan parasite Trypanosoma cruzi, showing a moderate potential (IC50 63.56 µg/mL) when compared to benznidazole (IC50 43.14 µg/mL). Otherwise, (-)- α-pinene oxide did not showed anti-trypanosomal activity (IC50 > 400 µg/mL) while (-)-pinane showed an IC50 of 56.50 µg/mL. The obtained results indicated that the epoxydation of α-pinene results to the loss of the anti-parasitic activity while its hydrogenation product, contributed slightly to the increased activity.

Anti-trypanosomal activity of 1,2,3,4,6-penta-O-galloyl-β -D-glucose isolated from Plectranthus barbatus Andrews (Lamiaceae)

MeOH extract from the leaves of Plectranthus barbatus Andrews (Lamiaceae), showed in vitro anti-trypanosomal activity. The bioassay-guided fractionation resulted in the isolation of a gallic acid derivative, identified as 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG), after thorough NMR and MS spectral analysis. Finally, this compound was tested against trypomastigote forms of T. cruzi and displayed an EC50 value of 67 µM, at least 6.6-fold more effective than the standard drug benznidazole. This is the first occurrence of PGG in the Plectranthus genus and the first anti-parasitic activity described for PGG in the literature.

ESTIRIL-LACTONAS DE Cryptocarya aschersoniana Mez. (Lauraceae Juss.) COM ATIVIDADE CONTRA Meloidogyne spp. E INTERAÇÃO IN SILICO COM PROVÁVEL FUMARASE DEMeloidogyne hapla

In a previous study, substances with nematicidal properties were detected in the bark of Cryptocarya aschersoniana. Continuing such study, the methanol extract from this plant underwent fractionation guided by in vitro assays with the plant-parasitic nematode Meloidogyne exigua. Two active compounds were isolated and identified by spectroscopic methods as (E)-6-styrylpyran-2-one and (R)-goniothalamin. The latter compound was also active againstMeloidogyne incognita. In silico studies carried out with (R)-goniothalamin and the enzyme fumarate hydratase, which was extracted from the genome of Meloidogyne hapla and modeled using computational methods, suggested that this substance acts against nematodes by binding to a cavity close to the active site of the enzyme.

Differential responses of nematode communities to soybean genotypes resistant and susceptible to Heterodera glycines race 3

Heterodera glycines and Helicotylenchus dihystera were the two most abundant plant-parasitic nematodes found in two H. glycines race 3-infested fields, Chapadão do Céu, MS and Campo Alegre, MG. These fields had been planted with resistant (R) and susceptible (S) plants to cyst nematodes. In the first field, soybean (Glycine max) FT-Cristalina (S) was susceptible to H. glycines but resistant to H. dihystera, while GOBR93 122243 (R) was just the opposite. In the second field, M-Soy 8400 (R) was more resistant to the spiral nematode than M-Soy8411 (S), but the resistance to the cyst nematode was not different between the two genotypes. The total abundance of nematodes was not different between the susceptible and resistant plants in the two fields, suggesting that H. dihystera and/or bacterial feeders and other trophic groups replaced the reduced abundance of the cyst nematodes in resistant plants. Bacterial feeders acted as a compensatory factor to plant-parasitic nematodes in ecological function. The populations of fungal feeders were higher in GOBR93 122243 (R) than in susceptible FT-Cristalina (S) in Chapadão do Céu, but lower in M-Soy 8400 (R) than in M-Soy 8411 (S) in Campo Alegre. This is being attributed to the different periods of soil samplings that were made at the florescent period in the first field, and at the final growing cycle in the second field. Only four nematodes, H. glycines, H. dihystera, Acrobeles sp. and Panagrolaimus sp. dominated the nematode resistant community GOBR93 122243 (R) in Chapadão do Céu, but dominance was shared by ten genera in Campo Alegre, which explains why the five diversity indexes (S, d, Ds, H' and T) were higher in resistant plants than in susceptible plants in field two.