99 research outputs found
Fresh-blood-free diet for rearing malaria mosquito vectors
Mosquito breeding depends on the supply of fresh vertebrate blood, a major bottleneck for large-scale production of Anopheles spp. Feeding alternatives to fresh blood are thus a priority for research, outdoor large-cage trials and control interventions. Several artificial meal compositions were tested and Anopheles oogenesis, egg laying and development into the next generation of adult mosquitoes were followed. We identified blood-substitute-diets that supported ovarian development, egg maturation and fertility as well as, low progeny larval mortality, and normal development of offspring into adult mosquitoes. The formulated diet is an effective artificial meal, free of fresh blood that mimics a vertebrate blood meal and represents an important advance for the sustainability of Anopheles mosquito rearing in captivity.Agência financiadora / Número do subsídio
Bill and Melinda Gates Foundation
OPP1138841
Fundacao para a Ciencia e Tecnologia
GHTM - UID/Multi/04413/201
CCMAR - UID/Multi/04326/2013
UID/Multi/04326/2013
RF SFRH/BPD/89811/2012
FAPEAM, Brazil
19716.UNI472.2459.20022014info:eu-repo/semantics/publishedVersio
Bias and Evolution of the Mutationally Accessible Phenotypic Space in a Developmental System
Genetic and developmental architecture may bias the mutationally available phenotypic spectrum. Although such asymmetries in the introduction of variation may influence possible evolutionary trajectories, we lack quantitative characterization of biases in mutationally inducible phenotypic variation, their genotype-dependence, and their underlying molecular and developmental causes. Here we quantify the mutationally accessible phenotypic spectrum of the vulval developmental system using mutation accumulation (MA) lines derived from four wild isolates of the nematodes Caenorhabditis elegans and C. briggsae. The results confirm that on average, spontaneous mutations degrade developmental precision, with MA lines showing a low, yet consistently increased, proportion of developmental defects and variants. This result indicates strong purifying selection acting to maintain an invariant vulval phenotype. Both developmental system and genotype significantly bias the spectrum of mutationally inducible phenotypic variants. First, irrespective of genotype, there is a developmental bias, such that certain phenotypic variants are commonly induced by MA, while others are very rarely or never induced. Second, we found that both the degree and spectrum of mutationally accessible phenotypic variation are genotype-dependent. Overall, C. briggsae MA lines exhibited a two-fold higher decline in precision than the C. elegans MA lines. Moreover, the propensity to generate specific developmental variants depended on the genetic background. We show that such genotype-specific developmental biases are likely due to cryptic quantitative variation in activities of underlying molecular cascades. This analysis allowed us to identify the mutationally most sensitive elements of the vulval developmental system, which may indicate axes of potential evolutionary variation. Consistent with this scenario, we found that evolutionary trends in the vulval system concern the phenotypic characters that are most easily affected by mutation. This study provides an empirical assessment of developmental bias and the evolution of mutationally accessible phenotypes and supports the notion that such bias may influence the directions of evolutionary change
The genetic basis of DOORS syndrome: an exome-sequencing study.
Deafness, onychodystrophy, osteodystrophy, mental retardation, and seizures (DOORS) syndrome is a rare autosomal recessive disorder of unknown cause. We aimed to identify the genetic basis of this syndrome by sequencing most coding exons in affected individuals
Notes on factorization algebras, factorization homology and applications
These notes are an expanded version of two series of lectures given at the
winter school in mathematical physics at les Houches and at the Vietnamese
Institute for Mathematical Sciences. They are an introduction to factorization
algebras, factorization homology and some of their applications, notably for
studying -algebras. We give an account of homology theory for manifolds
(and spaces), which give invariant of manifolds but also invariant of
-algebras. We particularly emphasize the point of view of factorization
algebras (a structure originating from quantum field theory) which plays, with
respect to homology theory for manifolds, the role of sheaves with respect to
singular cohomology. We mention some applications to the study of mapping
spaces and study several examples, including some over stratified spaces.Comment: 122 pages. A few examples adde
Evaluation of the effects of erythritol on gene expression in Brucella abortus
Bacteria of the genus Brucella have the unusual capability to catabolize erythritol and this property has been associated with their virulence mainly because of the presence of erythritol in bovine foetal tissues and because the attenuated S19 vaccine strain is the only Brucella strain unable to oxydize erythritol. In this work we have analyzed the transcriptional changes produced in Brucella by erythritol by means of two high throughput approaches: RNA hybridization against a microarray containing most of Brucella ORF's constructed from the Brucella ORFeome and next generation sequencing of Brucella mRNA in an Illumina GAIIx platform. The results obtained showed the overexpression of a group of genes, many of them in a single cluster around the ery operon, able to co-ordinately mediate the transport and degradation of erythritol into three carbon atoms intermediates that will be then converted into fructose-6P (F6P) by gluconeogenesis. Other induced genes participating in the nonoxidative branch of the pentose phosphate shunt and the TCA may collaborate with the ery genes to conform an efficient degradation of sugars by this route. On the other hand, several routes of amino acid and nucleotide biosynthesis are up-regulated whilst amino acid transport and catabolism genes are down-regulated. These results corroborate previous descriptions indicating that in the presence of erythritol, this sugar was used preferentially over other compounds and provides a neat explanation of the the reported stimulation of growth induced by erythritol
The Hexamer Structure of the Rift Valley Fever Virus Nucleoprotein Suggests a Mechanism for its Assembly into Ribonucleoprotein Complexes
Rift Valley fever virus (RVFV), a Phlebovirus with a genome consisting of three single-stranded RNA segments, is spread by infected mosquitoes and causes large viral outbreaks in Africa. RVFV encodes a nucleoprotein (N) that encapsidates the viral RNA. The N protein is the major component of the ribonucleoprotein complex and is also required for genomic RNA replication and transcription by the viral polymerase. Here we present the 1.6 Å crystal structure of the RVFV N protein in hexameric form. The ring-shaped hexamers form a functional RNA binding site, as assessed by mutagenesis experiments. Electron microscopy (EM) demonstrates that N in complex with RNA also forms rings in solution, and a single-particle EM reconstruction of a hexameric N-RNA complex is consistent with the crystallographic N hexamers. The ring-like organization of the hexamers in the crystal is stabilized by circular interactions of the N terminus of RVFV N, which forms an extended arm that binds to a hydrophobic pocket in the core domain of an adjacent subunit. The conformation of the N-terminal arm differs from that seen in a previous crystal structure of RVFV, in which it was bound to the hydrophobic pocket in its own core domain. The switch from an intra- to an inter-molecular interaction mode of the N-terminal arm may be a general principle that underlies multimerization and RNA encapsidation by N proteins from Bunyaviridae. Furthermore, slight structural adjustments of the N-terminal arm would allow RVFV N to form smaller or larger ring-shaped oligomers and potentially even a multimer with a super-helical subunit arrangement. Thus, the interaction mode between subunits seen in the crystal structure would allow the formation of filamentous ribonucleocapsids in vivo. Both the RNA binding cleft and the multimerization site of the N protein are promising targets for the development of antiviral drugs
Effects of fishery protection on biometry and genetic structure of two target sea cucumber species from the Mediterranean Sea
Sea cucumber fisheries are now occurring
in most of the tropical areas of the world, having
expanded from its origin in the central Indo-Pacific.
Due to the overexploitation of these resources and the
increasing demand from Asian countries, new target
species from Mediterranean Sea and northeastern
Atlantic Ocean are being caught. The fishery effects
on biometry and genetic structure of two target species
(Holothuria polii and H. tubulosa) from Turkey, were
assessed. The heaviest and largest individuals of H.
polii were found into the non-fishery area of Kusadasi,
also showing the highest genetic diversity. Similar
pattern was detected in H. tubulosa, but only the
weight was significantly higher in the protected area.
However, the observed differences on the fishery
effects between species, could be explained considering
the different percentage of catches (80% for H.
polii and 20% for H. tubulosa)
Rickettsia parkeri: a Rickettsial pathogen transmitted by ticks in endemic areas for spotted fever rickettsiosis in southern Uruguay
Postmortem Analyses Unveil the Poor Efficacy of Decontamination, Anti-Inflammatory and Immunosuppressive Therapies in Paraquat Human Intoxications
studies resulting from human PQ poisonings have assessed the relationship of these therapeutic measures with PQ toxicokinetics and related histopathological lesions, these being the aims of the present study.For that purpose, during 2008, we collected human fluids and tissues from five forensic autopsies following fatal PQ poisonings. PQ levels were measured by gas chromatography-ion trap mass spectrometry. Structural inflammatory lesions were evaluated by histological and immunohistochemistry analysis. The samples of cardiac blood, urine, gastric and duodenal wall, liver, lung, kidney, heart and diaphragm, showed quantifiable levels of PQ even at 6 days post-intoxication. Structural analysis showed diffused necrotic areas, intense macrophage activation and leukocyte infiltration in all analyzed tissues. By immunohistochemistry it was possible to observe a strong nuclear factor kappa-B (NF-κB) activation and excessive collagen deposition.Considering the observed PQ levels in all analyzed tissues and the expressive inflammatory reaction that ultimately leads to fibrosis, we conclude that the therapeutic protocol usually performed needs to be reviewed, in order to increase the efficacy of PQ elimination from the body as well as to diminish the inflammatory process
Nematode and Arthropod Genomes Provide New Insights into the Evolution of Class 2 B1 GPCRs
Nematodes and arthropods are the most speciose animal groups and possess Class 2 B1 G-protein coupled receptors
(GPCRs). Existing models of invertebrate Class 2 B1 GPCR evolution are mainly centered on Caenorhabditis elegans and
Drosophila melanogaster and a few other nematode and arthropod representatives. The present study reevaluates the
evolution of metazoan Class 2 B1 GPCRs and orthologues by exploring the receptors in several nematode and arthropod
genomes and comparing them to the human receptors. Three novel receptor phylogenetic clusters were identified and
designated cluster A, cluster B and PDF-R-related cluster. Clusters A and B were identified in several nematode and
arthropod genomes but were absent from D. melanogaster and Culicidae genomes, whereas the majority of the members of
the PDF-R-related cluster were from nematodes. Cluster A receptors were nematode and arthropod-specific but shared a
conserved gene environment with human receptor loci. Cluster B members were orthologous to human GCGR, PTHR and
Secretin members with which they probably shared a common origin. PDF-R and PDF-R related clusters were present in
representatives of both nematodes and arthropods. The results of comparative analysis of GPCR evolution and diversity in
protostomes confirm previous notions that C. elegans and D. melanogaster genomes are not good representatives of
nematode and arthropod phyla. We hypothesize that at least four ancestral Class 2 B1 genes emerged early in the metazoan
radiation, which after the protostome-deuterostome split underwent distinct selective pressures that resulted in duplication
and deletion events that originated the current Class 2 B1 GPCRs in nematode and arthropod genomes.This work was supported by the Portuguese Foundation for Science and Technology (FCT) project PTDC/BIA-BCM/114395/2009, by the European
Regional Development Fund through COMPETE and FCT under the project ‘‘PEst-C/MAR/LA0015/2011.’’ RCF is in receipt of an FCT grant (SFRH/BPD/89811/2012)
and JCRC is supported by auxiliary research contract FCT Pluriannual funds attributed to CCMAR. The funders had no role in study design, data collection and
analysis, decision to publish, or preparation of the manuscript
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