Association of the astrovirus structural protein VP90 with membranes plays a role in virus morphogenesis

VP90, the capsid polyprotein precursor of human astrovirus Yuc8, is assembled into viral particles, and its processing at the carboxy terminus by cellular caspases, to yield VP70, has been correlated with the cell release of the virus. Here, we characterized the effect of the VP90-VP70 processing on the properties of these proteins, as well as on their intracellular distribution. VP90 was found in membrane-enriched fractions (mVP90), as well as in fractions enriched in cytosolic proteins (cVP90), while VP70 was found exclusively in the latter fractions. Upon trypsin activation, infectivity was detected in all VP90-containing fractions, confirming that both mVP90 and cVP90 are able to assemble into particles; however, the two forms of VP90 showed differential sensitivities to trypsin, especially at their carboxy termini, which in the case of mVP90 was shown to remain membrane associated after protease digestion. Structural protein oligomers were detected in purified VP70-containing viruses, as well as in membrane-enriched fractions, but they were less evident in cytosolic fractions. Ultrastructural studies of infected cells revealed different types of viral particles, some of which appeared to be associated with membranes. By immunoelectron microscopy, structural proteins were shown to form virus particles in clusters and to associate with the edges of vesicles induced during infection, which also appear to contain subviral particles inside. Nonstructural proteins and viral RNA colocalized with mVP90, but not with cVP90, suggesting that mVP90 might represent the form of the protein that is initially assembled into particles, at the sites where the virus genome is being replicated.     

Absence of VanA- and VanB-Containing Enterococci in Poultry Raised on Nonintensive Production Farms in Brazil

We examined cloacal samples from poultry raised on nonintensive production farms in Brazil for the presence of vancomycin-resistant enterococci. No VanA- or VanB-containing enterococci were identified in a total of 200 cloacal swabs. The most prevalent species were Enterococcus gallinarum (vanC1; 13.0%) and E. casseliflavus (vanC2/3; 5.5%).     

The zebrafish mutant vps18 as a model for vesicle‐traffic related hypopigmentation diseases

Hypopigmentation is a characteristic of several diseases associated with vesicle traffic defects, like the Hermansky–Pudlak, Chediak–Higashi, and Griscelli syndromes. Hypopigmentation is also a characteristic of the zebrafish mutant vps18^hi2499A, which is affected in the gene vps18, a component of the homotypic fusion and protein sorting complex that is involved in tethering during vesicular traffic. Vps18, as part of this complex, participates in the formation of early endosomes, late endosomes, and lysosomes. Here, we show that Vps18 is also involved in the formation of melanosomes. In the zebrafish mutant vps18^hi2499A the retroviral insertion located at exon 4 of vps18, leads to the formation of two abnormal splicing variants lacking the coding sequence for the clathrin repeat and the RING finger conserved domains. A deficiency of Vps18 in zebrafish larvae results in hepatomegaly and skin hypopigmentation. We also observed a drastic reduction in the number of melanosomes in the eye's retinal pigmented epithelium along with the accumulation of immature melanosomes. A significant reduction in the vps18^hi2499A larvae visual system capacity was found using the optokinetic response assay. We propose that the insertional mutant vps18^hi2499A can be used as a model for studying hypopigmentation diseases in which vesicle traffic problems exist.     

Morphology of the fifth sternal glands of Neotropical social wasps (Hymenoptera,Vespidae, Polistinae)

Glands play a central role in the social behavior of insects, and comparative analysis of their structure may provide insights about their evolution and their role in insect social biology. Here, we describe the glands of the fifth metasomal sternite of ten polistine wasps with different social behaviors. The glands of foragers of these species were studied using semithin sections of Araldite‐embedded tissue, and scanning electron microscopy. The structure of the glands observed was mostly similar to what has previously been reported for independent‐founder and swarm‐founder species, respectively. Scale‐shaped modifications in the fifth sternite are reported for the first time for members of the genera Synoeca and Epipona. Two previously unreported glands in the fifth sternite are also described. A more restrictive definition of the name Richards' gland is proposed, applying to the class 3 cells associated with scale modifications of the fifth sternite, based on structural differences between the glands observed, homology requirements, and functional evidence. Previous phylogenetic reconstructions of this character suggest that it appeared early in the Vespidae and disappeared four times, with a single reappearance in the genus Vespula. The restricted definition of Richards' gland suggests that this structure is an exclusive trait of the Epiponini, with two reversals.     

Developmental trends of theta–beta interelectrode power correlation during resting state in normal children

The possibility that power-to-power (theta–beta) frequency coupling increases during development was analyzed. Three minutes of spontaneous EEG in an open eyes condition were recorded in a sample of 160 subjects ranging from 6 to 26 years old. Theta (4–7 Hz) and beta band (15–20 Hz) power was calculated in a trial-by-trial basis. Inter-electrode power correlations (IPC) were computed in each subject as the correlation between the power of two frequency bands recorded in two electrodes. An increase in theta–beta IPC with age was obtained. IPCs were higher when theta was seeded in posterior regions than in anterior or central regions. Moreover, the significant correlations between each individual IPC and age were calculated, making it possible to draw IPC versus age correlation maps in order to capture the IPC development topography. An increase was found in significant correlations in the left hemisphere compared to the right hemisphere. There were no differences in the inter-hemispheric versus intra-hemispheric IPC maturation spatial patterns. An increase in power-to-power–frequency coupling in theta–beta occurs during development, suggesting an increase in functional connectivity with age. Frequency coupling between theta and beta rhythms would be one of the mechanisms facilitating integration of long distance functional networks during development.     

Salt lakes of La Mancha (Central Spain): A hot spot for tiger beetle (Carabidae,Cicindelinae) species diversity

The tiger beetle assemblage of the wetlands of La Mancha (central Spain) comprises nine species: Calomera littoralis littoralis, Cephalota maura maura, Cephalota circumdata imperialis, Cephalota dulcinea, Cicindela campestris campestris, Cicindela maroccana, Cylindera paludosa, Lophyra flexuosa flexuosa, and Myriochila melancholica melancholica. This assemblage represents the largest concentration of tiger beetles in a single 1º latitude / longitude square in Europe. General patterns of spatial and temporal segregation among species are discussed based on observations of 1462 specimens registered during an observation period of one year, from April to August. The different species of Cicindelini appear to be distributed over space and time, with little overlapping among them. Three sets of species replace each other phenologically as the season goes on. Most of the species occupy drying or dried salt lakes and salt marshes, with sparse vegetation cover. Spatial segregation is marked in terms of substrate and vegetation use. Calomera littoralis and Myriochila melancholica have been observed mainly on wet soils; Cephalota circumdata on dry open saline flats; Cephalota dulcinea and Cylindera paludosa in granulated substrates with typical halophytic vegetation; Cephalota maura is often present in man-modified areas. Cephalota circumdata and Cephalota dulcinea are included as species of special interest in the list of protected species in Castilla–La Mancha. Conservation problems for the Cicindelini assemblage arise from agricultural activities and inadequate use of sport vehicles. Attempts at restoring the original habitat, supressing old semi-industrial structures, may affect the spatial heterogeneity of the lakes, and have an effect on Cicindelinae diversity.     

Is livestock grazing compatible with amphibian diversity in the High Mountains of Córdoba, Argentina?

The High Mountains of Córdoba, Argentina have a long evolutionary history of grazing by large herbivores. However, about 400?years ago, European livestock were introduced and gradually replaced native herbivores. Since the 1920s, domestic herbivores have been the only large herbivores present in the area, causing severe soil erosion and a threat to the system diversity. The endemic fauna of the region includes four amphibian species. We evaluated the effect of livestock rearing on amphibian diversity and water bodies in woodlands and grasslands of the High Mountains of Córdoba. The work was conducted on stream stretches and ponds in two contrasting grazing situations: an area with livestock presence and another area where livestock was excluded 14?years ago. The following variables were recorded at each sampling site: amphibian richness and abundance, percentage of emergent, submerged and peripheral vegetation in areas surrounding the water bodies, water pH, and water dissolved O₂. No significant differences were detected in amphibian diversity between streams of both grazing situations, whereas a greater diversity (p?<?0.01) was observed in ponds in grazed grasslands. Our results suggest that livestock rearing, qualitatively measured as grazing and 14?years of livestock exclusion, in the study area would not have negative effects on amphibian diversity. This finding might be due to the long evolutionary grazing history of the area, large-scale livestock exclusion exhibiting a novel scenario. The ongoing reintroduction of native grazers may provide the benefits of grazing without the consequent soil erosion and habitat degradation associated with domestic livestock.     

Classification of Dengue Fever Patients Based on Gene Expression Data Using Support Vector Machines

Background

Symptomatic infection by dengue virus (DENV) can range from dengue fever (DF) to dengue haemorrhagic fever (DHF), however, the determinants of DF or DHF progression are not completely understood. It is hypothesised that host innate immune response factors are involved in modulating the disease outcome and the expression levels of genes involved in this response could be used as early prognostic markers for disease severity.

Methodology/Principal Findings

mRNA expression levels of genes involved in DENV innate immune responses were measured using quantitative real time PCR (qPCR). Here, we present a novel application of the support vector machines (SVM) algorithm to analyze the expression pattern of 12 genes in peripheral blood mononuclear cells (PBMCs) of 28 dengue patients (13 DHF and 15 DF) during acute viral infection. The SVM model was trained using gene expression data of these genes and achieved the highest accuracy of ∼85% with leave-one-out cross-validation. Through selective removal of gene expression data from the SVM model, we have identified seven genes (MYD88, TLR7, TLR3, MDA5, IRF3, IFN-α and CLEC5A) that may be central in differentiating DF patients from DHF, with MYD88 and TLR7 observed to be the most important. Though the individual removal of expression data of five other genes had no impact on the overall accuracy, a significant combined role was observed when the SVM model of the two main genes (MYD88 and TLR7) was re-trained to include the five genes, increasing the overall accuracy to ∼96%.

Conclusions/Significance

Here, we present a novel use of the SVM algorithm to classify DF and DHF patients, as well as to elucidate the significance of the various genes involved. It was observed that seven genes are critical in classifying DF and DHF patients: TLR3, MDA5, IRF3, IFN-α, CLEC5A, and the two most important MYD88 and TLR7. While these preliminary results are promising, further experimental investigation is necessary to validate their specific roles in dengue disease.     

Expression of the selectable marker gene bsrm in BALB/MK cells induces apoptosis by overproduction of hydrogen peroxide.

Transduction of the retroviral vector LBmSN, which expresses the blasticidin S resistance gene bsrm in the murine keratinocyte cell line BALB/MK, induces death in these cells. Cell death is caused by a factor called DOKEB (death factor obtained from keratinocytes expressing bsrm), which is released before the cells' death. In this report we describe and discuss the purification and characterization of DOKEB. Our results were as follows. (i) The 5-day-old medium from the modified BALB/MK cells with LBmSN was used for purification and characterization by filtration and chromatography: DOKEB was a stable and highly hydrophilic compound, with a molecular mass less than that of 1 amino acid. (ii) The conditioned medium containing DOKEB was reactive against thiobarbituric acid and dichlorofluorescein diacetate. (iii) DOKEB activity was neutralized by the incubation of the conditioned medium with catalase. Therefore, our conclusion is that the BALB/MK cells expressing bsrm produce a large amount of hydrogen peroxide, which catalyzes the process of apoptosis of those cells.