RNA interference (RNAi) pathways are widespread in metaozoans but the genes required show variable occurrence or activity eukaryotic microbes, including many pathogens. While some Leishmania lack RNAi and Argonaute Dicer genes, we that braziliensis other species within subgenus Viannia elaborate active machinery. Strong attenuation of expression from a variety reporter endogenous was seen. As expected, knockdowns sole gene implicated this protein RNAi. The potential for functional genetics...

Invertebrate stages of Leishmania are capable genetic exchange during their extracellular growth and development in the sand fly vector. Here we explore two variables: ability diverse L. major strains from across its natural range to undergo mating pairwise tests; timing appearance hybrids developmental stage associations within both (Phlebotomus duboscqi) unnatural (Lutzomyia longipalpis) vectors. Following co-infection flies with parental lines bearing independent drug markers, doubly-drug...

Hybrid genotypes have been repeatedly described among natural isolates of Leishmania, and the recovery experimental hybrids from sand flies co-infected with different strains or species Leishmania has formally demonstrated that members genus possess machinery for genetic exchange. As neither gamete stages nor cell fusion events directly observed during parasite development in vector, we relied on a classical analysis to determine if true sexual cycle. Here, used whole genome sequencing...

The viral kinetics of documented SARS-CoV-2 infections exhibit a high degree inter-individual variability. We identified six distinct shedding patterns, which differed according to peak load, duration, expansion rate and clearance rate, by clustering data from 768 in the National Basketball Association cohort. Omicron variant previously vaccinated individuals generally led lower cumulative levels than other scenarios. then developed mechanistic mathematical model that recapitulated 1510...

Abstract In a pivotal trial (EPIC-HR), 5-day course of oral ritonavir-boosted nirmatrelvir, given early during symptomatic SARS-CoV-2 infection (within three days symptoms onset), decreased hospitalization and death by 89.1% nasal viral load 0.87 log relative to placebo in high-risk individuals. Yet, nirmatrelvir/ritonavir failed as post-exposure prophylaxis trial, frequent rebound has been observed subsequent cohorts. We develop mathematical model capturing viral-immune dynamics...

ABSTRACT Galactofuranose (Gal f ) is a novel sugar absent in mammals but present variety of pathogenic microbes, often within glycoconjugates that play critical roles cell surface formation and the infectious cycle. In prokaryotes, Gal synthesized as nucleotide UDP-Gal by UDP-galactopyranose mutase (UGM) (gene GLF ). Here we used combinatorial bioinformatics screen to identify family candidate eukaryotic s had previously escaped detection. from three pathogens, two protozoa ( Leishmania...

Surface glycoconjugates play important roles in the infectious cycle of Leishmania major , including abundant lipophosphoglycan (LPG) implicated parasite survival sand fly vector and initial stages establishment mammalian host macrophage. We describe a system for inducible expression LPG, applying novel protein-based that allows controlled degradation key LPG biosynthetic enzyme, UDP-galactopyranose mutase (UGM). This methodology relies on mutated FK506-binding protein (FKBP) destabilizing...

Three phenylpropanoid dimers (1–3) including two new metabolites were isolated from the extract of twigs Nectandra leucantha using antileishmanial bioassay-guided fractionation. The in vitro antiparasitic activity compounds against Leishmania donovani parasites and mammalian cytotoxicity immunomodulatory effects evaluated. Compounds 1–3 effective intracellular amastigotes within macrophages, with IC50 values 26.7, 17.8, 101.9 μM, respectively. cytotoxicity, given by 50% cytotoxic...

Significance Leishmania parasites can be infected with Leishmaniavirus (LRV1), a double-stranded RNA virus whose presence in guyanensis exacerbates disease severity both mouse models and humans. Studies of the role on parasite biology virulence are hampered by dearth isogenic lines bearing lacking LRV, particularly clinically important species braziliensis . Here, we describe method to systematically generate LRV1-free using interference (RNAi) pathway. The ability transgene-driven RNAi...

The oxidative burst generated by the host immune system can restrict intracellular parasite entry and growth. While this leads to induction of antioxidative enzymes, molecular mechanisms consequences counter-response on life human parasites are largely unknown. transcription factor NF-E2-related (NRF2) could be a key mediator antioxidant signaling during infection due parasites. Here, we showed that NRF2 was strongly upregulated in with Leishmania protozoan parasites, its activation...

Here we studied ability of two naphthoquinones to inhibit Leishmania growth (2,3-dichloro-5,8-dihydroxy-1,4-naphthoquinone (TR 001) and 2,3-dibromo-1,4-naphthoquinone 002). TR 001 was more efficient than 002 in inducing killing promastigotes intracellular amastigotes. These values compare well those obtained with the standard first-line antileishmanial agent sodium stibogluconate (SSG). also induced significantly nitric oxide (NO) production or SSG. Taken together, these data show that could...

Summary Among trypanosomatid protozoa the mechanism of RNA interference ( RNAi ) has been investigated in T rypanosoma brucei and to a lesser extent L eishmania braziliensis . Although these two parasitic organisms belong same family, they are evolutionarily distantly related raising questions about conservation pathway. Here we carried out an in‐depth analysis small interfering RNAs siRNAs associated with Argonaute1 br AGO 1). In contrast , sensitive 3′ end oxidation, indicating absence...

Protozoan parasites contain negatively charged polymers of a few up to several hundreds phosphate residues. In other organisms, these poly-phosphate (polyP) chains serve as an energy source and reservoir, have been implicated in adaptation stress virulence pathogenic organisms. this study, we confirmed first that the polyP polymerase vacuolar transporter chaperone 4 (VTC4) is responsible for synthesis Leishmania parasites. During Leishmaniain vitro culture, accumulated logarithmic growth...

The lymphatic system plays a crucial role in mounting immune response against intracellular pathogens, and recent studies have documented its facilitating tumor dissemination linked largely with cancer cells. However, mucocutaneous leishmaniasis (MCL) caused by Leishmania Viannia subgenus showing infectious metastasis resulting severe distant secondary lesions, the route of escape these parasites to sites has not yet been investigated detail. Our results demonstrated that when infection was...

Abstract In a pivotal trial (EPIC-HR), 5-day course of oral ritonavir-boosted nirmatrelvir, given early during symptomatic SARS-CoV-2 infection (within three days symptoms onset), decreased hospitalization and death by 89.1% nasal viral load 0.87 log relative to placebo in high-risk individuals. Yet, nirmatrelvir/ritonavir failed as post-exposure prophylaxis trial, frequent rebound has been observed subsequent cohorts. We developed mathematical model capturing viral-immune dynamics...

RNA interference (RNAi) is a powerful tool whose efficacy against broad range of targets enables functional genetic tests individually or systematically. However, the RNAi pathway has been lost in evolution by variety eukaryotes including most Leishmania sp. was retained species subgenus Viannia, and here we describe development, optimization, application tools to study L. (Viannia) braziliensis (Lbr). We developed vectors facilitating generation long-hairpin "stem-loop" (StL) knockdown...

Abstract The viral kinetics of documented SARS-CoV-2 infections exhibit a high degree inter-individual variability. We identified six distinct shedding patterns, which differed according to peak load, duration, expansion rate and clearance rate, by clustering data from 768 in the National Basketball Association cohort. Omicron variant previously vaccinated individuals generally led lower cumulative levels than other scenarios. then developed mechanistic mathematical model that recapitulated...

Reduced activity of the enzymes encoded by PHGDH, PSAT1, and PSPH causes a set ultrarare, autosomal recessive diseases known as serine biosynthesis defects. These present in broad phenotypic spectrum: at severe end is Neu-Laxova syndrome, intermediate range are infantile defects with neurological manifestations growth deficiency, mild childhood disease intellectual disability. However, L-serine supplementation, especially if started early, can ameliorate some cases even prevent symptoms....

ABSTRACT RNA interference (RNAi) is a powerful tool whose efficacy against broad range of targets enables functional genetic tests individually or systematically. However, the RNAi pathway has been lost in evolution by variety eukaryotes including most Leishmania sp. was retained species subgenus Viannia , and here we describe development, optimization, application tools to study L. (Viannia) braziliensis . We developed vectors facilitating generation long-hairpin “stem-loop” (StL) knockdown...

Abstract The success of chimeric antigen receptor (CAR) T-cell therapy in treating hematologic malignancies has generated widespread interest translating this technology to solid cancers. However, issues like tumor infiltration, the immunosuppressive microenvironment, and heterogeneity limit its efficacy setting. Recent experimental clinical studies propose local administration directly into or at site increase CAR infiltration improve treatment outcomes. Characteristics types tumors that...

Molnupiravir is an antiviral medicine that induces lethal copying errors during SARS-CoV-2 RNA replication. reduced hospitalization in one pivotal trial by 50% and had variable effects on reducing viral levels three separate trials. We used mathematical models to simulate these trials closely recapitulated their virologic outcomes. Model simulations suggest lower potency against pre-omicron variants than omicron. estimate vitro assays underestimate vivo 7-8 fold omicron variants. Our model...

Pathogenic variants in PHGDH, PSAT1 , and PSPH cause a set of rare, autosomal recessive diseases known as serine biosynthesis defects. Serine defects present broad phenotypic spectrum that includes, at the severe end, Neu-Laxova syndrome, lethal multiple congenital anomaly disease, intermediately form infantile with neurological manifestations growth deficiency, mild childhood disease intellectual disability. However, because L-serine supplementation, especially if started early, can...

We leverage data-driven model discovery methods to determine governing equations for the emergent behavior of heterogeneous networked dynamical systems. Specifically, we consider networks coupled nonlinear oscillators whose collective approaches a limit cycle. Stable cycles are interest in many biological applications, as they self-sustained oscillations (e.g. heartbeats, chemical oscillations, neurons firing, circadian rhythm). For systems that display relaxation our method automatically...

RNA interference (RNAi) is a powerful tool for genetic analysis. While many Leishmania species lost the RNAi pathway deep in evolution, within subgenus Viannia retain genes. Correspondingly, introduction of constructs expressing dsRNA L. (V.) braziliensis resulted substantial down regulation all target mRNAs tested. We are optimizing and developing protocols that will facilitate use applied them to study flagellum. developed vectors allowing rapid generation stem‐loop (StL) using Gateway...

Leishmaniasis is a spectral disease caused by the Trypanosomatid protozoan parasite Leishmania . One manifestation disfiguring mucocutaneous form (MCL) involving dissemination to nasopharyngeal areas and tissue destruction, species from South American subgenus Viannia We reported previously that metastatic L. guyanensis bear high levels of novel dsRNA totivirus (LRV1), while non‐metastatic lines have low or lack LRV1. LRV1‐infected were associated with hyper‐inflammatory response dependent...