In silico design of a <Emphasis Type="Italic">Zika virus</Emphasis> non-structural protein 5 aiming vaccine protection against zika and dengue in different human populations

Background

The arboviruses Zika virus (ZIKV) and Dengue virus (DENV) have important epidemiological impact in Brazil and other tropical regions of the world. Recently, it was shown that previous humoral immunity to DENV enhances ZIKV replication in vitro, which may lead to more severe forms of the disease. Thus, traditional approaches of vaccine development aiming to control viral infection through neutralizing antibodies may induce cross-reactive enhancing antibodies. In contrast, cellular immune response was shown to be capable of controlling DENV infection independently of antibodies. The aim of the present study was to design a flavivirus NS5 protein capable of inducing a cellular immune response against DENV and ZIKV.

Methods

A consensus sequence of ZIKV NS5 protein was designed among isolates from various continents. Epitopes were predicted for the most prevalent alleles of class I and II HLA in the Brazilian population. Then, this epitopes were analyzed with regard to their conservation, population coverage and distribution along the whole antigen.

Results

Nineteen epitopes predicted to be more reactive (percentile rank <1) and 100% conserved among ZIKV and DENV serotypes were selected. The distribution of such epitopes along the protein was shown on a three-dimensional model and population coverage was calculated for different regions of the world. The designed protein was predicted to be stable and the distribution of selected epitopes was shown to be homogeneous along domains. The population coverage of selected epitopes was higher than 50% for most of tropical areas of the world.

Conclusion

Such results indicate that the proposed antigen has the potential to induce protective cellular immune response to ZIKV and DENV in different human populations of the world.

     

Expression of fibroblast growth factor 10 and cognate receptors in the developing bovine ovary

In the mammalian ovary, FGF10 is expressed in oocytes and theca cells and is a candidate for paracrine signaling to the developing granulosa cells. To gain insight into the participation of FGF10 in the regulation of fetal folliculogenesis, we assessed mRNA expression patterns of FGF10 and its receptors, FGFR1B and FGFR2B, in relation to fetal follicle dynamics and localized FGF10 protein in bovine fetal ovaries at different ages. Primordial, primary, secondary, and antral follicles were first observed on Days 75, 90, 150, and 210 of gestation, respectively. The levels of GDF9 and BMP15 mRNA, markers for primordial and primary follicles, respectively, increased during fetal ovary development in a consistent manner with fetal follicle dynamics. CYP17A1 mRNA abundance increased from Day 60 to Day 75 and then from Day 120 to Day 150, coinciding with the appearance of secondary follicles. FGF10 mRNA abundance increased from Day 90, and this increase was temporally associated with increases in FGFR1B mRNA abundance and in the population of primary follicles. In contrast, FGFR2B mRNA expression was highest on Day 60 and decreased thereafter. FGF10 protein was localized to oogonia and oocytes and surrounding granulosa cells at all fetal ages. The present data suggest a role for FGF10 in the control of fetal folliculogenesis in cattle.     

Two new species of <Emphasis Type="Italic">Bertolonia</Emphasis> (Melastomataceae) from the Brazilian Atlantic Forest

Bertolonia alternifolia and B. bullata, two new endemic species of Melastomataceae from the Atlantic Forest biome of the southern region of Bahia state, Brazil, are described and illustrated based on recent botanical explorations and literature records. The main diagnostic characteristics that distinguish B. alternifolia are alternate leaves with cordate bases, and anthers with terminal-dorsal pores and unappendaged connectives. B. bullata can be identified by having leaves bullate on the adaxial surface, foveolate on the abaxial surface and bases cordate to cordate-lobate, calyx lobes with entire to slightly undulate margins, and stamens dorsally appendaged. Both species are classified as Critically Endangered (CR) and Endangered (EN) respectively.     

Auditory saccular sensitivity of the vocal Lusitanian toadfish: low frequency tuning allows acoustic communication throughout the year

A novel form of auditory plasticity for enhanced detection of social signals was described in a teleost fish, Porichthys notatus (Batrachoididae, Porichthyinae). The seasonal onset of male calling coincides with inshore migration from deep waters by both sexes and increased female sensitivity to dominant frequencies of male calls. The closely related Lusitanian toadfish, Halobatrachus didactylus, (Batrachoididae, Halophryninae) also breeds seasonally and relies on acoustic communication to find mates but, instead, both sexes stay in estuaries and show vocal activity throughout the year. We investigated whether the sensitivity of the inner ear saccule of H. didactylus is seasonally plastic and sexually dimorphic. We recorded evoked potentials from populations of saccular hair cells from non-reproductive and reproductive males and females in response to 15–945 Hz tones. Saccular hair cells were most sensitive at 15–205 Hz (thresholds between 111 and 118 dB re. 1 μPa). Both sexes showed identical hearing sensitivity and no differences were found across seasons. The saccule was well suited to detect conspecific vocalizations and low frequencies that overlapped with lateral line sensitivity. We showed that the saccule in H. didactylus has major importance in acoustic communication throughout the year and that significant sensory differences may exist between the two batrachoidid subfamilies.     

A semiparametric estimator of the bivariate distribution function for censored gap times

Let (T(1), T(2)) be gap times corresponding to two consecutive events, which are observed subject to random right-censoring. In this paper, a semiparametric estimator of the bivariate distribution function of (T(1), T(2)) and, more generally, of a functional E [φ(T(1),T(2))] is proposed. We assume that the probability of censoring for T(2) given the (possibly censored) gap times belongs to a parametric family of binary regression curves. We investigate the conditions under which the introduced estimator is consistent. We explore the finite sample behavior of the estimator and of its bootstrap standard error through simulations. The main conclusion of this paper is that the semiparametric estimator may be much more efficient than purely nonparametric methods. Real data illustration is included.     

Immunization with P10 Peptide Increases Specific Immunity and Protects Immunosuppressed BALB/c Mice Infected with Virulent Yeasts of Paracoccidioides brasiliensis

Paracoccidioidomycosis is a systemic granulomatous disease caused by Paracoccidioides spp. A peptide from the major diagnostic antigen gp43, named P10, induces a T-CD4⁺ helper-1 immune response in mice and protects against intratracheal challenge with virulent P. brasiliensis. Previously, we evaluated the efficacy of the P10 peptide alone or combined with antifungal drugs in mice immunosuppressed and infected with virulent isolate of P. brasiliensis. In the present work, our data suggest that P10 immunization leads to an effective cellular immune response associated with an enhanced T cell proliferative response. P10-stimulated splenocytes increased nitric oxide (NO) production and induced high levels of IFN-γ, IL-1β and IL-12. Furthermore, significantly increased concentrations of pro-inflammatory cytokines were also observed in lung homogenates of immunized mice. P10 immunization was followed by minimal fibrosis in response to infection. Combined with antifungal drugs, P10 immunization most significantly improved survival of anergic infected mice. Administration of either itraconazole or sulfamethoxazole/trimethoprim together with P10 immunization resulted in 100 % survival up to 200 days post-infection, whereas untreated mice died within 80 days. Hence, our data show that P10 immunization promotes a strong specific immune response even in immunocompromised hosts and thus P10 treatment represents a powerful adjuvant therapy to chemotherapy.     

Interaction of a Partially Disordered Antisigma Factor with Its Partner,the Signaling Domain of the TonB-Dependent Transporter HasR

Bacteria use diverse signaling pathways to control gene expression in response to external stimuli. In Gram-negative bacteria, the binding of a nutrient is sensed by an outer membrane transporter. This signal is then transmitted to an antisigma factor and subsequently to the cytoplasm where an ECF sigma factor induces expression of genes related to the acquisition of this nutrient. The molecular interactions involved in this transmembrane signaling are poorly understood and structural data on this family of antisigma factor are rare. Here, we present the first structural study of the periplasmic domain of an antisigma factor and its interaction with the transporter. The study concerns the signaling in the heme acquisition system (Has) of Serratia marcescens. Our data support unprecedented partially disordered periplasmic domain of an anti-sigma factor HasS in contact with a membrane-mimicking environment. We solved the 3D structure of the signaling domain of HasR transporter and identified the residues at the HasS−HasR interface. Their conservation in several bacteria suggests wider significance of the proposed model for the understanding of bacterial transmembrane signaling.