Molecular Characterization of Spirometra decipiens Complex (Eucestoda: Diphyllobothriidea) from Uruguay

This study used a partial sequence of the mitochondrial cox1 gene for the reconstruction of the interrelationship of the adult and larval stages of Spirometra obtained from Cerdocyon thous, Leopardus munoai, Canis familiaris, Didelphis albiventris and Philodryas patagoniensis in Uruguay. The phylogenetic analysis showed that they were grouped with Spirometra decipiens from the Americas with a high bootstrap support. According to recent studies, American Spirometra species split into two S. decipiens complexes. Our findings strongly suggest that S. decipiens complex 1 is widely distributed in South America, and that wild and domestic canids are definitive hosts. Most of the samples (n = 10) grouped adults and plerocercoids that were retrieved from mammals and reptiles and seem to be the same taxon found in a Lycalopex gymnocercus from Argentina. A second clade was formed with Spirometra sp. found in a L. munoai as well as other wild felids such as a Puma concolor and a Leopardus pardalis (both from Argentina). On the other hand, S. decipiens complex 2 is present in South America and North America. South American clade parasitizes wild (and possibly domestic) felids and reptiles as definitive and intermediate hosts, respectively, whereas the North American clade found in snakes and captive meerkats (acting either as second intermediate or paratenic hosts) has unconfirmed definitive hosts.

Phylogenetics of the genus Sechium P. Brown: A review

The Sechium P. Br. genus composed of 11 species, which originated from the mountainous regions of Mesoamerica, have been domesticated and diversified. These species are clustered in two large groups: the Mexican clade and the Central American clade. Morphological and molecular studies have shown that species of the Mexican clade are formed through interspecific hybridizations and genetic flow, with the exception of S. mexicanum, which is strongly linked to the genus Sicyos. The objective of this review was to analyze the phylogenetics of Sechium based on morphological and molecular studies, which contributed to taxonomic knowledge and utilization, thereby favoring its conservation and improvement. The Central American clade is well supported with molecular data, but not so with morphological data. The species in this clade were geographically isolated and endemic. S. edule and S. tacaco are exploited species in the agricultural and industrial sectors, and both have an extensive genetic and phenotypic diversity that has allowed them to diversify and expand into different ecological niches. Finally, the Central American species of Sechium thrive in adverse environments of temperatures of mesophyll forest and high relative humidity, with characteristics that can give resistance to frosts and phytopathogenic agents, as well as cultivated species of this genus.

New Insights on the Zika Virus Arrival in the Americas and Spatiotemporal Reconstruction of the Epidemic Dynamics in Brazil

Zika virus (ZIKV) became a worldwide public health emergency after its introduction in the Americas. Brazil was implicated as central in the ZIKV dispersion, however, a better understanding of the pathways the virus took to arrive in Brazil and the dispersion within the country is needed. An updated genome dataset was assembled with publicly available data. Bayesian phylogeography methods were applied to reconstruct the spatiotemporal history of ZIKV in the Americas and with more detail inside Brazil. Our analyses reconstructed the Brazilian state of Pernambuco as the likely point of introduction of ZIKV in Brazil, possibly during the 2013 Confederations Cup. Pernambuco played an important role in spreading the virus to other Brazilian states. Our results also underscore the long cryptic circulation of ZIKV in all analyzed locations in Brazil. Conclusions: This study brings new insights about the early moments of ZIKV in the Americas, especially regarding the Brazil-Haiti cluster at the base of the American clade and describing for the first time migration patterns within Brazil.

Whole-Genome Sequencing Reveals a Novel Subclade of Pansusceptible Candida auris in Ontario, Canada

Background:Candida auris is an emerging pathogen that has recently disseminated globally and caused challenging outbreaks in healthcare facilities (HCFs), in part because it is commonly multidrug-resistant. Candida auris remains rare in Canada, with ~20 known cases to date. We describe the emergence of a novel subclade of C. auris in Ontario, Canada, using whole-genome sequencing (WGS). Methods: In Ontario, many HCFs submit yeast isolates from sterile sites requiring species-level characterization and antifungal susceptibility testing (AFST) to the provincial reference laboratory. Yeasts were identified using a combination of standard methods (morphology, API 20C, MALDI-ToF MS) including ITS2 sequencing. Sensititre YO9 panels were used for AFST. Genomic analysis of C. auris was performed using an Illumina HiSeq platform with at least 50× coverage; variants were called against the reference genome by using the previously published North Arizona SNP pipeline (NASP). Phylogenetic trees were produced by maximum parsimony method (MEGA7.0). Results: Between 2014 and 2018, yeast isolates from 5 different patients from 4 HCFs in the same region of Ontario were confirmed to be C. auris by ITS2 PCR and sequence analysis (Table 1). Based on interim CDC criteria for antifungal drug break points, all isolates were pansusceptible to common antifungals. WGS analysis demonstrated that the C. auris isolates were part of the South American clade (IV) and formed an isolated subclade that is well supported by bootstrap analysis, indicating clonal relationships among these isolates (Fig. 1). Conclusions: Although C. auris isolates are usually drug resistant, all 5 initial Ontario isolates were pansusceptible. WGS determined that these isolates clustered within clade IV and were clonal. This cluster of C. auris appears to represent a new subclade of the South American clade that has been transmitted among patients within a region of Ontario. C. auris may have been present in Ontario for some time, escaping earlier detection due to lack of screening programs in HCFs, historical challenges with microbiologic detection of C. auris, and the antifungal susceptibility of the circulating isolates. Investigations are underway to determine clinical features and epidemiologic relatedness among patients in this cluster.Funding: NoneDisclosures: Susy Hota, Contracted Research - Finch Therapeutics

Global assessment of genetic paradigms of Pvmdr1 mutations in chloroquine-resistant Plasmodium vivax isolates

Background Chloroquine (CQ) is generally prescribed as the front-line antimalarial drug of choice to treat Plasmodium vivax infections; however, some clinical CQ-resistant P. vivax isolates have been indigenously reported around the world during the last decade. Methods In this study, P. vivax isolates (n=52) were obtained from autochthonous samples in southeast Iran during 2015–2017. The genomic DNA of samples was extracted, amplified (nested PCR) and sequenced by targeting the multidrug-resistance 1 gene. To verify the global genetic diversity of CQ-resistant P. vivax strains, the sequences of Pvmdr1 originating from Asia and the Americas were retrieved. Results A total of 46 haplotypes were grouped into three distinct geographical haplogroups. The haplotype diversity and occurrence rates of Pvmdr1 976F/1076L mutations indicate that the efficacy of CQ is being compromised in Mexico, China, Nicaragua, Thailand, Brazil (2016), Ethiopia, Mauritania (2012) and southwest India in the near future. The cladistic phylogenetic tree showed that Pvmdr1 sequences isolated from the southeast Asian clade has a partial sister relationship with the American clade. Conclusions The current findings will serve as a basis to develop appropriate malaria control strategies and public health policies in symptomatic imported malaria cases or plausible CQ-resistant P. vivax strains.

What does mitogenomics tell us about the evolutionary history of the Drosophila buzzatii cluster (repleta group)

The Drosophila repleta group is an array of more than 100 cactophilic species endemic to the “New World”. The acquisition of the ability to utilize decaying cactus tissues as breeding and feeding sites is a key aspect that allowed the successful diversification of the repleta group in the American deserts. Within this group, the Drosophila buzzatii cluster is a South American clade of seven cactophilic closely related species in different stages of divergence, a feature that makes it a valuable model system for evolutionary research. However, even though substantial effort has been devoted to elucidating the phylogenetic relationships among members of the D. buzzatii cluster, the issue is still controversial. In effect, molecular phylogenetic studies performed to date generated ambiguous results since tree topologies depend on the kind of molecular marker employed. Curiously, even though mitochondrial DNA has become a popular marker in evolutionary biology and population genetics, none of the more than twenty Drosophila mitogenomes assembled so far belongs to this cluster. In this work we report the assembly of six complete mitogenomes of five species: D. antonietae, D. borborema, D. buzzatii, D. seriema and two strains of D. koepferae, with the aim to revisit the phylogenetic relationships and divergence times by means of a mitogenomic approach. The recovered topology using complete mitogenomes gives support to the hypothesis of the monophyly of that the D. buzzatii cluster and shows two main clades, one including D. buzzatii and D. koepferae (both strains) and the other the remaining species. These results are in agreement with previous reports based on a few mitochondrial and/or nuclear genes but in conflict with the results of a recent large-scale nuclear phylogeny, suggesting that nuclear and mitochondrial genomes depict different evolutionary histories.

Genetic Bases Of Aposematic Traits: Insights from the Skin Transcriptional Profiles of Oophaga Poison Frogs

Aposematic organisms advertise their defensive toxins to predators using a variety of warning signals, including bright coloration. While most Neotropical poison frogs (Dendrobatidae) rely on crypsis to avoid predators, Oophaga poison frogs from South America advertise their chemical defenses, a complex mix of diet-derived alkaloids, by using conspicuous hues. The present study aimed to characterize the skin transcriptomic profiles of the South American clade of Oophaga poison frogs (O. anchicayensis, O. solanensis, O. lehmanni and O. sylvatica). Our analyses showed very similar transcriptomic profiles for these closely related species in terms of functional annotation and relative abundance of gene ontology terms expressed. Analyses of expression profiles of Oophaga and available skin transcriptomes of cryptic anurans allowed us to propose possible mechanisms for the active sequestration of alkaloid-based chemical defenses and to highlight some genes that may be potentially involved in resistance mechanisms to avoid self-intoxication and skin coloration. In doing so, we provide an important molecular resource for the study of warning signals that will facilitate the assembly and annotation of future poison frog genomes.