A species complex (= species group, species series) is an assemblage of species, which are related morphologically and phylogenetically. Recent research has revealed several arthropod vector species ...that were believed to be a single nominal species actually representing a group of closely related species, which are sometimes morphologically indistinguishable at one or more developmental stages. In some instances, differences in terms of vector competence, capacity, or both have been recorded. It highlights the importance of detecting and studying species complexes to improve our understanding of pathogen transmission patterns, which may be vectored more or less efficiently by different species within the complex. Considering more than 540 species, about one‐third of the phlebotomine sand flies in the New World present males and/or females morphologically indistinguishable to one or more species. Remarkably, several of these species may act in transmission of pathogenic agents. In this article, we review recent research on species complexes in phlebotomine sand flies from the Americas. Possible practical implications of recently acquired knowledge and future research needs are also discussed.
Species complex is a fairly common phenomenon in many groups of arthropod vectors, including mosquitoes, ticks and phlebotomine sand flies.
Cryptic species may have significant difference in behaviour, biology and ecology that may impact control measures.
Around one‐third of American phlebotomine sand fly species are indistinguishable morphologically, including important vectors of Leishmania spp.
Members of species complexes may play different roles in the transmission of pathogens to their hosts.
Blood-feeding behavior has independently evolved in arthropods multiple times. Unlike hard ticks, soft ticks employ a rapid-feeding strategy for hematophagy, and there are comparatively limited ...studies on the transcriptomes of these organisms. This study investigates the soft tick Ornithodoros hermsi, conducting histopathological examinations at bitten skin sites and tick whole-body transcriptomic analyses across various developmental and feeding stages, including larvae, 1st-nymphal, and 2nd-nymphal stages. The results revealed the ability of O. hermsi to induce skin hemorrhage at the bite sites. Transcriptomic analyses identified three consistent transcriptional profiles: unfed, early-fed (6 h, 12 h, 24 h), and late-fed (5 days). The unfed profile exhibited high transcriptional activity across most of the functional classes annotated. In contrast, early-fed stages exhibited decreased expression of most functional classes, except for the unknown, which is highly expressed. Finally, transcriptional expression of most functional classes increased in the late-fed groups, resembling the baseline expression observed in the unfed groups. These findings highlight intense pre-feeding transcriptional activity in O. hermsi ticks, aligning with their rapid-feeding strategy. Moreover, besides shedding light on the temporal dynamics of key pathways during blood meal processing and tick development, this study contributes significantly to the transcriptome repertoire of a medically relevant soft tick species with relatively limited prior knowledge.
The Zika virus (ZIKV) is a neurotropic arbovirus considered a global threat to public health. Although there have been several efforts in drug discovery projects for ZIKV in recent years, there are ...still no antiviral drugs approved to date. Here, we describe the results of a global collaborative crowdsourced open science project, the OpenZika project, from IBM’s World Community Grid (WCG), which integrates different computational and experimental strategies for advancing a drug candidate for ZIKV. Initially, molecular docking protocols were developed to identify potential inhibitors of ZIKV NS5 RNA-dependent RNA polymerase (NS5 RdRp), NS3 protease (NS2B-NS3pro), and NS3 helicase (NS3hel). Then, a machine learning (ML) model was built to distinguish active vs inactive compounds for the cytoprotective effect against ZIKV infection. We performed three independent target-based virtual screening campaigns (NS5 RdRp, NS2B-NS3pro, and NS3hel), followed by predictions by the ML model and other filters, and prioritized a total of 61 compounds for further testing in enzymatic and phenotypic assays. This yielded five non-nucleoside compounds which showed inhibitory activity against ZIKV NS5 RdRp in enzymatic assays (IC50 range from 0.61 to 17 μM). Two compounds thermally destabilized NS3hel and showed binding affinity in the micromolar range (K d range from 9 to 35 μM). Moreover, the compounds LabMol-301 inhibited both NS5 RdRp and NS2B-NS3pro (IC50 of 0.8 and 7.4 μM, respectively) and LabMol-212 thermally destabilized the ZIKV NS3hel (Kd of 35 μM). Both also protected cells from death induced by ZIKV infection in in vitro cell-based assays. However, while eight compounds (including LabMol-301 and LabMol-212) showed a cytoprotective effect and prevented ZIKV-induced cell death, agreeing with our ML model for prediction of this cytoprotective effect, no compound showed a direct antiviral effect against ZIKV. Thus, the new scaffolds discovered here are promising hits for future structural optimization and for advancing the discovery of further drug candidates for ZIKV. Furthermore, this work has demonstrated the importance of the integration of computational and experimental approaches, as well as the potential of large-scale collaborative networks to advance drug discovery projects for neglected diseases and emerging viruses, despite the lack of available direct antiviral activity and cytoprotective effect data, that reflects on the assertiveness of the computational predictions. The importance of these efforts rests with the need to be prepared for future viral epidemic and pandemic outbreaks.
This objective of this work was to assess the knowledge of students in public schools about rabies and leishmaniasis, through educational interventions. A total of 628 questionnaires were applied in ...public students from Apodi, Felipe Guerra and Severiano Melo. The questionnaires were administered before and after the educational interventions in the form of lectures. The data were discussed through a descriptive analysis. Before the presentation, 53.9% of students claimed to know the transmission mode of leishmaniasis and after, this percentage increased to 92.2%. However, before the lectures, only 6.0% of respondents associated the transmission to sandflies, and after, this percentage increased to 75.7%. For rabies, before the lectures, 63.7% of students reported knowing how rabies is transmitted and, after the lectures, 92.8% said how it was the transmission. Concerning the transmission, before the presentations, 68.3% reported that it was through bite or injury of animals and, after the lectures, the index increased to 80.4%. In conclusion, the student´s perception of public education on rabies and leishmaniasis was higher in all aspects addressed after educational intervention compared to the same questions about the knowledge of the disease before the intervention. It also concludes that the perception of students for rabies is greater than for leishmaniasis.
The use of casein, starch and bee pollen as biodegradable materials has been promise. The objective of this work was the development and characterization of films containing casein, pollen and ...starch. The films were obtained by casting process and the solvent evaporation was performed at 40 °C/24 h. The films characterization was carried out by microscopy, thermal analysis, opacity test, mechanical properties and barrier methods. The starch films presented heterogeneous on microscopy analysis. The thermal behaviors of pollen films were similar. The formulation containing only pollen 3% was unable to form film. The introduction of pollen in starch film formulation improved the mechanical characteristic and thermal stability of films.
Characterization of Ph
2Sn(Cl)(MBT) (
1) (HMBT=2-mercaptobenzothiazole) has been carried out by IR, Mössbauer,
1H,
13C and
119Sn spectroscopies and by X-ray crystallography for
1 together with that ...of Ph
2Sn(SCH
2CH
2S) (
2). Compound
1, unexpectedly obtained from the reaction between Ph
2SnCl
2 and KMBT in a 1:2 mole ratio, has a trigonal-bipyramidal geometry, due to intramolecular SnN interactions, both in the solid state and in solution; the axial sites are occupied by N and Cl, N(24)SnCl(4)=155.27(17)°, the chelate bite angle, N(24)SNS(15), is 64.65(17)°. Compound
2 is essentially monomeric in the solid state and has a distorted tetrahedral structure; the bond angles at tin vary from 92.50(16)° S(2)SnS(5) to 116.4(6)° C(6)SnC(12). The shortest intermolecular Sn⋯S contact in
2 is 3.885 Å, just within the sum of the van der Waals’ radii for Sn and S (4.0 Å). PM3 semi-empirical calculations for
2 indicated that the geometry at the tin center can be accounted for by a high degree of p-character in the tin bonding orbitals to sulfur; PM3 semi-empirical calculations on Ph
2Sn(SCH
2CH
2CH
2S) (
3) indicated the geometry at tin to be less distorted from tetrahedral, with a SSnS angle of 99°; the calculations further indicated that the only stable conformation of the six-membered ring in
3 is the chair form.
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