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Background: This study evaluated the effectiveness of Baby Friendly Spaces (BFS), a psychosocial support program for Rohingya refugee mothers of malnourished young children in Bangladesh. Because BFS was already being implemented, we examined the benefit of enhancing implementation supports. Methods: In matched pairs, 10 sites were randomized to provide BFS treatment as usual (BFS-TAU) or to receive enhanced implementation support (BFS-IE). 600 mothers were enrolled and reported on maternal distress, functional impairment, subjective well-being and coping at baseline and 8-week follow-up. Data were analyzed using multilevel linear regression models to account for clustering; sensitivity analyses adjusted for the small number of clusters. Results: Significant within-group improvements in BFSIE were observed for distres (-.48, p = .014), functional impairment (-.30, p = .002) and subjective well-being (.92, p = .011); improvements in BFS-TAU were smaller and not statistically significant. Between-group comparisons favored BFS-IE for distress (ß = -.30, p = .058) and well-being (ß = .58, p = .038). Sensitivity adjustments produced p-values above .05 for all between-group comparisons. Discussion: Feasible adjustments to implementation can improve program delivery to increase impact on maternal distress and well-being. Although results should be interpreted with caution, study design limitations are common in pragmatic, field-based research.
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Toxoplasma gondii is a foodborne pathogen that can cause severe and life-threatening infections in fetuses and immunocompromised patients. Felids are its only definitive hosts, and a wide range of animals, including humans, serve as intermediate hosts. When the transmissible bradyzoite stage is orally ingested by felids, they transform into merozoites that expand asexually, ultimately generating millions of gametes for the parasite sexual cycle. However, bradyzoites in intermediate hosts differentiate exclusively to disease-causing tachyzoites, which rapidly disseminate throughout the host. Though tachyzoites are well-studied, the molecular mechanisms governing transitioning between developmental stages are poorly understood. Each parasite stage can be distinguished by a characteristic transcriptional signature, with one signature being repressed during the other stages. Switching between stages require substantial changes in the proteome, which is achieved in part by ubiquitination. F-box proteins mediate protein poly-ubiquitination by recruiting substrates to SKP1, Cullin-1, F-Box protein E3 ubiquitin ligase (SCF-E3) complexes. We have identified an F-box protein named Toxoplasma gondii F-Box Protein L2 (TgFBXL2), which localizes to distinct perinucleolar sites. TgFBXL2 is stably engaged in an SCF-E3 complex that is surprisingly also associated with a COP9 signalosome complex that negatively regulates SCF-E3 function. At the cellular level, TgFBXL2-depleted parasites are severely defective in centrosome replication and daughter cell development. Most remarkable, RNAseq data show that TgFBXL2 conditional depletion induces the expression of stage-specific genes including a large cohort of genes necessary for sexual commitment. Together, these data suggest that TgFBXL2 is a latent guardian of stage specific gene expression in Toxoplasma and poised to remove conflicting proteins in response to an unknown trigger of development.
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Proteínas de Protozoários , Toxoplasma , Toxoplasma/genética , Toxoplasma/metabolismo , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/genética , Animais , Humanos , Proteínas F-Box/metabolismo , Proteínas F-Box/genética , Toxoplasmose/parasitologia , Toxoplasmose/metabolismo , Toxoplasmose/genética , Estágios do Ciclo de VidaRESUMO
Ribonucleoprotein complexes are composed of RNA, RNA-dependent proteins (RDPs) and RNA-binding proteins (RBPs), and play fundamental roles in RNA regulation. However, in the human malaria parasite, Plasmodium falciparum, identification and characterization of these proteins are particularly limited. In this study, we use an unbiased proteome-wide approach, called R-DeeP, a method based on sucrose density gradient ultracentrifugation, to identify RDPs. Quantitative analysis by mass spectrometry identifies 898 RDPs, including 545 proteins not yet associated with RNA. Results are further validated using a combination of computational and molecular approaches. Overall, this method provides the first snapshot of the Plasmodium protein-protein interaction network in the presence and absence of RNA. R-DeeP also helps to reconstruct Plasmodium multiprotein complexes based on co-segregation and deciphers their RNA-dependence. One RDP candidate, PF3D7_0823200, is functionally characterized and validated as a true RBP. Using enhanced crosslinking and immunoprecipitation followed by high-throughput sequencing (eCLIP-seq), we demonstrate that this protein interacts with various Plasmodium non-coding transcripts, including the var genes and ap2 transcription factors.
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Plasmodium , RNA , Humanos , RNA/metabolismo , Plasmodium falciparum/genética , Plasmodium falciparum/metabolismo , Proteoma/metabolismo , Proteínas de Ligação a RNA/metabolismo , Plasmodium/genéticaRESUMO
Over the last few decades, novel methods have been developed to study how chromosome positioning within the nucleus may play a role in gene regulation. Adaptation of these methods in the human malaria parasite, Plasmodium falciparum, has recently led to the discovery that the three-dimensional structure of chromatin within the nucleus may be critical in controlling expression of virulence genes (var genes). Recent work has implicated an unusual, highly conserved var gene called var2csa in contributing to coordinated transcriptional switching, however how this gene functions in this capacity is unknown. To further understand how var2csa influences var gene switching, targeted DNA double-strand breaks (DSBs) within the sub-telomeric region of chromosome 12 were used to delete the gene and the surrounding chromosomal region. To characterize the changes in chromatin architecture stemming from this deletion and how these changes could affect var gene expression, we used a combination of RNA-seq, Chip-seq and Hi-C to pinpoint epigenetic and chromatin structural modifications in regions of differential gene expression. We observed a net gain of interactions in sub-telomeric regions and internal var gene regions following var2csa knockout, indicating an increase of tightly controlled heterochromatin structures. Our results suggest that disruption of var2csa results not only in changes in var gene transcriptional regulation but also a significant tightening of heterochromatin clusters thereby disrupting coordinated activation of var genes throughout the genome. Altogether our result confirms a strong link between the var2csa locus, chromatin structure and var gene expression.
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Babesiosis, caused by protozoan parasites of the genus Babesia , is an emerging tick-borne disease of significance for both human and animal health. Babesia parasites infect erythrocytes of vertebrate hosts where they develop and multiply rapidly to cause the pathological symptoms associated with the disease. The identification of various Babesia species underscores the ongoing risk of new zoonotic pathogens capable of infecting humans, a concern amplified by anthropogenic activities and environmental shifts impacting the distribution and transmission dynamics of parasites, their vectors, and reservoir hosts. One such species, Babesia MO1, previously implicated in severe cases of human babesiosis in the midwestern United States, was initially considered closely related to B. divergens , the predominant agent of human babesiosis in Europe. Yet, uncertainties persist regarding whether these pathogens represent distinct variants of the same species or are entirely separate species. We show that although both B. MO1 and B. divergens share similar genome sizes, comprising three nuclear chromosomes, one linear mitochondrial chromosome, and one circular apicoplast chromosome, major differences exist in terms of genomic sequence divergence, gene functions, transcription profiles, replication rates and susceptibility to antiparasitic drugs. Furthermore, both pathogens have evolved distinct classes of multigene families, crucial for their pathogenicity and adaptation to specific mammalian hosts. Leveraging genomic information for B. MO1, B. divergens , and other members of the Babesiidae family within Apicomplexa provides valuable insights into the evolution, diversity, and virulence of these parasites. This knowledge serves as a critical tool in preemptively addressing the emergence and rapid transmission of more virulent strains.
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Humanitarian crises such as disease outbreaks, conflict and displacement and natural disasters affect millions of people primarily in low- and middle-income countries. Here, they often reside in areas with poor environmental health conditions leading to an increased burden of infectious diseases such as gastrointestinal and respiratory infections. Water, sanitation, and hygiene behaviours are critical to prevent such infections and deaths. A scoping review was conducted to map out what is known about the association between three mental health disorders and people's perceived and actual ability to practice hygiene-related behaviours, particularly handwashing, in humanitarian and pandemic crises. Published and grey literature was identified through database searches, humanitarian-relevant portals, and consultations with key stakeholders in the humanitarian sector. 25 publications were included, 21 were peer-reviewed published articles and four were grey literature publications. Most of the studies were conducted in mainland China (n = 12) and most were conducted in an outbreak setting (n = 20). Six studies found a positive correlation between handwashing and anxiety where participants with higher rates of anxiety were more likely to practice handwashing with soap. Four studies found an inverse relationship where those with higher rates of anxiety were less likely to wash their hands with soap. The review found mixed results for the association between handwashing and depression, with four of the seven studies reporting those with higher rates of depression were less likely to wash their hands, while the remaining studies found that higher depression scores resulted in more handwashing. Mixed results were also found between post-traumatic stress disorder (PTSD) and handwashing. Two studies found that lower scores of PTSD were associated with better hygiene practices, including handwashing with soap. The contradictory patterns suggest that researchers and practitioners need to explore this association further, in a wider range of crises, and need to standardize tools to do so.
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Saúde Mental , Sabões , Humanos , Pandemias/prevenção & controle , Higiene , Transtornos de Ansiedade , Saneamento , Desinfecção das MãosRESUMO
Malaria-associated pathogenesis such as parasite invasion, egress, host cell remodelling and antigenic variation requires concerted action by many proteins, but the molecular regulation is poorly understood. Here we have characterized an essential Plasmodium-specific Apicomplexan AP2 transcription factor in Plasmodium falciparum (PfAP2-P; pathogenesis) during the blood-stage development with two peaks of expression. An inducible knockout of gene function showed that PfAP2-P is essential for trophozoite development, and critical for var gene regulation, merozoite development and parasite egress. Chromatin immunoprecipitation sequencing data collected at timepoints matching the two peaks of pfap2-p expression demonstrate PfAP2-P binding to promoters of genes controlling trophozoite development, host cell remodelling, antigenic variation and pathogenicity. Single-cell RNA sequencing and fluorescence-activated cell sorting revealed de-repression of most var genes in Δpfap2-p parasites. Δpfap2-p parasites also overexpress early gametocyte marker genes, indicating a regulatory role in sexual stage conversion. We conclude that PfAP2-P is an essential upstream transcriptional regulator at two distinct stages of the intra-erythrocytic development cycle.
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Malária , Parasitos , Plasmodium , Animais , Malária/parasitologia , Regulação da Expressão Gênica , Plasmodium falciparum/genéticaRESUMO
IMPORTANCE: The classical depiction of the Toxoplasma lifecycle is bradyzoite excystation conversion to tachyzoites, cell lysis, and immune control, followed by the reestablishment of bradyzoites and cysts. In contrast, we show that tachyzoite growth slows independent of the host immune response at a predictable time point following excystation. Furthermore, we demonstrate a host cell-dependent pathway of continuous amplification of the cyst-forming bradyzoite population. The developmental plasticity of the excysted bradyzoites further underlines the critical role the cyst plays in the flexibility of the lifecycle of this ubiquitous parasite. This revised model of Toxoplasma recrudescence uncovers previously unknown complexity in the clinically important bradyzoite stage of the parasite, which opens the door to further study these novel developmental features of the Toxoplasma intermediate life cycle.
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Toxoplasma , Animais , Toxoplasma/metabolismo , Estágios do Ciclo de Vida , Proteínas de Protozoários/metabolismoRESUMO
The Aurora family of kinases orchestrates chromosome segregation and cytokinesis during cell division, with precise spatiotemporal regulation of its catalytic activities by distinct protein scaffolds. Plasmodium spp., the causative agents of malaria, are unicellular eukaryotes with three unique and highly divergent aurora-related kinases (ARK1-3) that are essential for asexual cellular proliferation but lack most canonical scaffolds/activators. Here we investigate the role of ARK2 during sexual proliferation of the rodent malaria Plasmodium berghei, using a combination of super-resolution microscopy, mass spectrometry, and live-cell fluorescence imaging. We find that ARK2 is primarily located at spindle microtubules in the vicinity of kinetochores during both mitosis and meiosis. Interactomic and co-localisation studies reveal several putative ARK2-associated interactors including the microtubule-interacting protein EB1, together with MISFIT and Myosin-K, but no conserved eukaryotic scaffold proteins. Gene function studies indicate that ARK2 and EB1 are complementary in driving endomitotic division and thereby parasite transmission through the mosquito. This discovery underlines the flexibility of molecular networks to rewire and drive unconventional mechanisms of chromosome segregation in the malaria parasite.
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Divisão do Núcleo Celular , Segregação de Cromossomos , Animais , Plasmodium berghei/genética , Proliferação de Células , Meiose , Aurora Quinases , EucariotosRESUMO
Genes and regulatory mechanisms governing malaria parasite transmission and development in mosquitoes are incompletely understood. Recently, Russell and colleagues identified genes required for parasite sexual development. In this issue of Cell Host & Microbe, Ukegbu and colleagues report a genetic approach to study genes enabling parasite survival in mosquito stages.
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Culicidae , Plasmodium , Animais , Culicidae/genética , Plasmodium/genéticaRESUMO
The complex life cycle of Plasmodium falciparum requires coordinated gene expression regulation to allow host cell invasion, transmission, and immune evasion. Increasing evidence now suggests a major role for epigenetic mechanisms in gene expression in the parasite. In eukaryotes, many lncRNAs have been identified to be pivotal regulators of genome structure and gene expression. To investigate the regulatory roles of lncRNAs in P. falciparum we explore the intergenic lncRNA distribution in nuclear and cytoplasmic subcellular locations. Using nascent RNA expression profiles, we identify a total of 1768 lncRNAs, of which 718 (~41%) are novels in P. falciparum. The subcellular localization and stage-specific expression of several putative lncRNAs are validated using RNA-FISH. Additionally, the genome-wide occupancy of several candidate nuclear lncRNAs is explored using ChIRP. The results reveal that lncRNA occupancy sites are focal and sequence-specific with a particular enrichment for several parasite-specific gene families, including those involved in pathogenesis and sexual differentiation. Genomic and phenotypic analysis of one specific lncRNA demonstrate its importance in sexual differentiation and reproduction. Our findings bring a new level of insight into the role of lncRNAs in pathogenicity, gene regulation and sexual differentiation, opening new avenues for targeted therapeutic strategies against the deadly malaria parasite.
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Malária Falciparum , Malária , Parasitos , RNA Longo não Codificante , Humanos , Animais , Plasmodium falciparum/genética , RNA Longo não Codificante/genética , Malária Falciparum/genéticaRESUMO
As a public health burden, severe acute malnutrition (SAM) among children has been increasingly studied to determine the optimal combination of treatment approaches. Among the new approaches is the addition of early childhood development sessions to standard nutrition-based treatment for SAM which can enhance both nutrition and development outcomes among young children. However, few studies demonstrate the relationship between the costs of such combined programs and the benefits accrued to the children and their caregivers. This article describes our experience of designing and conducting an economic evaluation alongside a cluster randomized controlled trial assessing a combined nutrition and psychosocial intervention for the treatment of SAM in children aged 6-24 months in Nepal. We present key lessons learned regarding methodological choices, the challenges of field data collection, as well as study adjustment when data analysis did not unfold as anticipated. With the view to transparency, this manuscript provides some clarifications on the evaluation processes for funders and policy makers on what economic evaluations entail and what information they convey for the purpose of supporting policy decision-making around limited resource allocation.
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Desnutrição Aguda Grave , Criança , Pré-Escolar , Humanos , Análise Custo-Benefício , Nepal , Avaliação de Programas e Projetos de Saúde , Desnutrição Aguda Grave/terapia , Pessoal AdministrativoRESUMO
Background: In response to the psychological distress experienced by people affected by the onset of the COVID-19 pandemic, Action Against Hunger (Action contre la Faim, ACF) developed and implemented the Emotional and Stress Management Intervention (ESMI) in Liberia, Sierra Leone, and Ivory Coast. ESMI is a person-to-person two-session, non-specialized, mental health and psychosocial support intervention for adults and adolescents in the general population based in problem solving therapy and principles of emotional regulation. Methods: Using de-identified programmatic data for each country, we conducted paired t-tests to assess whether adults and adolescents who received ESMI experienced changes in reported psychological distress and perceived social support following the intervention. We also performed pairwise correlations to test whether there were associations between changes in distress and social support over the course of participation in ESMI. Descriptive analyses were performed for presenting problems and coping strategies reported during the sessions. Results: Mean scores for psychological distress at baseline and follow-up were significantly different in all countries: Sierra Leone (mean (m) = -6.11; 95% confidence interval (CI) = -6.25 to -5.96); Ivory Coast (m = -3.21; 95% CI = -3.33 to -3.10); and Liberia (m = -2.86; 95% CI = -3.15 to -2.56). Changes in perceived social support were also statistically significant for Sierra Leone (m = 6.87; 95% CI = 6.72-7.02); Ivory Coast (m = 3.12; 95% CI = 2.97-3.27); and Liberia (m = 1.13; 95% CI = 1.00-1.27). Correlations (r) between changes in distress and changes in social support varied by country, and ranged from negative in Liberia, (r = -0.88, P = 0.001), to positive in Ivory Coast (r = 55, P = 0.001), and null in Sierra Leone (r = -0.07, P = 0.11). Conclusions: Our findings show changes in psychological distress and perceived social support for participants who completed two sessions of ESMI, suggesting a potential benefit of ESMI as a person-to-person mental health and psychosocial support for individuals in distress affected by a pandemic. A future randomized controlled trial with a focus on key implementation factors (i.e., pre-testing visual analogue scales, treatment fidelity, and comparison of in-person vs remote) is recommended as next steps in research.
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COVID-19 , Doença pelo Vírus Ebola , Adulto , Adolescente , Humanos , Serra Leoa/epidemiologia , Saúde Mental , Libéria/epidemiologia , Pandemias , Côte d'Ivoire/epidemiologia , COVID-19/terapia , COVID-19/epidemiologia , Sistemas de Apoio Psicossocial , Doença pelo Vírus Ebola/epidemiologiaRESUMO
Plasmodium falciparum, the human malaria parasite, infects two hosts and various cell types, inducing distinct morphological and physiological changes in the parasite in response to different environmental conditions. These variations required the parasite to adapt and develop elaborate molecular mechanisms to ensure its spread and transmission. Recent findings have significantly improved our understanding of the regulation of gene expression in P. falciparum. Here, we provide an up-to-date overview of technologies used to highlight the transcriptomic adjustments occurring in the parasite throughout its life cycle. We also emphasize the complementary and complex epigenetic mechanisms regulating gene expression in malaria parasites. This review concludes with an outlook on the chromatin architecture, the remodeling systems, and how this 3D genome organization is critical in various biological processes.
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Malária Falciparum , Parasitos , Humanos , Animais , Montagem e Desmontagem da Cromatina , Epigênese Genética , Cromatina/genéticaRESUMO
Mosquito-borne disease remains a significant burden on global health. In the United States, the major threat posed by mosquitoes is transmission of arboviruses, including West Nile virus by mosquitoes of the Culex genus. Virus metagenomic analysis of mosquito small RNA using deep sequencing and advanced bioinformatic tools enables the rapid detection of viruses and other infecting organisms, both pathogenic and non-pathogenic to humans, without any precedent knowledge. In this study, we sequenced small RNA samples from over 60 pools of Culex mosquitoes from two major areas of Southern California from 2017 to 2019 to elucidate the virome and immune responses of Culex. Our results demonstrated that small RNAs not only allowed the detection of viruses but also revealed distinct patterns of viral infection based on location, Culex species, and time. We also identified miRNAs that are most likely involved in Culex immune responses to viruses and Wolbachia bacteria, and show the utility of using small RNA to detect antiviral immune pathways including piRNAs against some pathogens. Collectively, these findings show that deep sequencing of small RNA can be used for virus discovery and surveillance. One could also conceive that such work could be accomplished in various locations across the world and over time to better understand patterns of mosquito infection and immune response to many vector-borne diseases in field samples.
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Culex , Culicidae , Viroses , Humanos , Animais , Mosquitos Vetores , AntiviraisRESUMO
Malaria pathogenicity results from the parasite's ability to invade, multiply within and then egress from the host red blood cell (RBC). Infected RBCs are remodeled, expressing antigenic variant proteins (such as PfEMP1, coded by the var gene family) for immune evasion and survival. These processes require the concerted actions of many proteins, but the molecular regulation is poorly understood. We have characterized an essential Plasmodium specific Apicomplexan AP2 (ApiAP2) transcription factor in Plasmodium falciparum (PfAP2-MRP; Master Regulator of Pathogenesis) during the intraerythrocytic developmental cycle (IDC). An inducible gene knockout approach showed that PfAP2-MRP is essential for development during the trophozoite stage, and critical for var gene regulation, merozoite development and parasite egress. ChIP-seq experiments performed at 16 hour post invasion (h.p.i.) and 40 h.p.i. matching the two peaks of PfAP2-MRP expression, demonstrate binding of PfAP2-MRP to the promoters of genes controlling trophozoite development and host cell remodeling at 16 h.p.i. and antigenic variation and pathogenicity at 40 h.p.i. Using single-cell RNA-seq and fluorescence-activated cell sorting, we show de-repression of most var genes in Δpfap2-mrp parasites that express multiple PfEMP1 proteins on the surface of infected RBCs. In addition, the Δpfap2-mrp parasites overexpress several early gametocyte marker genes at both 16 and 40 h.p.i., indicating a regulatory role in the sexual stage conversion. Using the Chromosomes Conformation Capture experiment (Hi-C), we demonstrate that deletion of PfAP2-MRP results in significant reduction of both intra-chromosomal and inter-chromosomal interactions in heterochromatin clusters. We conclude that PfAP2-MRP is a vital upstream transcriptional regulator controlling essential processes in two distinct developmental stages during the IDC that include parasite growth, chromatin structure and var gene expression.
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Pathogenic protists are a group of organisms responsible for causing a variety of human diseases including malaria, sleeping sickness, Chagas disease, leishmaniasis, and toxoplasmosis, among others. These diseases, which affect more than one billion people globally, mainly the poorest populations, are characterized by severe chronic stages and the lack of effective antiparasitic treatment. Parasitic protists display complex life-cycles and go through different cellular transformations in order to adapt to the different hosts they live in. Autophagy, a highly conserved cellular degradation process, has emerged as a key mechanism required for these differentiation processes, as well as other functions that are crucial to parasite fitness. In contrast to yeasts and mammals, protist autophagy is characterized by a modest number of conserved autophagy-related proteins (ATGs) that, even though, can drive the autophagosome formation and degradation. In addition, during their intracellular cycle, the interaction of these pathogens with the host autophagy system plays a crucial role resulting in a beneficial or harmful effect that is important for the outcome of the infection. In this review, we summarize the current state of knowledge on autophagy and other related mechanisms in pathogenic protists and their hosts. We sought to emphasize when, how, and why this process takes place, and the effects it may have on the parasitic cycle. A better understanding of the significance of autophagy for the protist life-cycle will potentially be helpful to design novel anti-parasitic strategies.
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The human malaria parasites, including Plasmodium falciparum, persist as a major cause of global morbidity and mortality. The recent stalling of progress toward malaria elimination substantiates a need for novel interventions. Controlled gene expression is central to the parasite's numerous life cycle transformations and adaptation. With few specific transcription factors (TFs) identified, crucial roles for chromatin states and epigenetics in parasite transcription have become evident. Although many chromatin-modifying enzymes are known, less is known about which factors mediate their impacts on transcriptional variation. Like those of higher eukaryotes, long noncoding RNAs (lncRNAs) have recently been shown to have integral roles in parasite gene regulation. This review aims to summarize recent developments and key findings on the role of lncRNAs in P. falciparum.
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Malária Falciparum , Malária , Parasitos , RNA Longo não Codificante , Animais , Humanos , Parasitos/genética , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Regulação da Expressão Gênica , Malária Falciparum/parasitologia , Cromatina/metabolismo , Plasmodium falciparum/genética , Plasmodium falciparum/metabolismo , Malária/parasitologiaRESUMO
Babesiosis is a malaria-like disease in humans and animals that is caused by Babesia species, which are tick-transmitted apicomplexan pathogens. Babesia duncani causes severe to lethal infection in humans, but despite the risk that this parasite poses as an emerging pathogen, little is known about its biology, metabolic requirements or pathogenesis. Unlike other apicomplexan parasites that infect red blood cells, B. duncani can be continuously cultured in vitro in human erythrocytes and can infect mice resulting in fulminant babesiosis and death. We report comprehensive, detailed molecular, genomic, transcriptomic and epigenetic analyses to gain insights into the biology of B. duncani. We completed the assembly, 3D structure and annotation of its nuclear genome, and analysed its transcriptomic and epigenetics profiles during its asexual life cycle stages in human erythrocytes. We used RNA-seq data to produce an atlas of parasite metabolism during its intraerythrocytic life cycle. Characterization of the B. duncani genome, epigenome and transcriptome identified classes of candidate virulence factors, antigens for diagnosis of active infection and several attractive drug targets. Furthermore, metabolic reconstitutions from genome annotation and in vitro efficacy studies identified antifolates, pyrimethamine and WR-99210 as potent inhibitors of B. duncani to establish a pipeline of small molecules that could be developed as effective therapies for the treatment of human babesiosis.
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Babesia , Babesiose , Carrapatos , Animais , Humanos , Camundongos , Babesia/genética , Babesiose/tratamento farmacológico , Multiômica , Eritrócitos/parasitologiaRESUMO
Mechanisms of cell division are remarkably diverse, suggesting the underlying molecular networks among eukaryotes differ extensively. The Aurora family of kinases orchestrates the process of chromosome segregation and cytokinesis during cell division through precise spatiotemporal regulation of their catalytic activities by distinct scaffolds. Plasmodium spp., the causative agents of malaria, are unicellular eukaryotes that have three divergent aurora-related kinases (ARKs) and lack most canonical scaffolds/activators. The parasite uses unconventional modes of chromosome segregation during endomitosis and meiosis in sexual transmission stages within mosquito host. This includes a rapid threefold genome replication from 1N to 8N with successive cycles of closed mitosis, spindle formation and chromosome segregation within eight minutes (termed male gametogony). Kinome studies had previously suggested likely essential functions for all three Plasmodium ARKs during asexual mitotic cycles; however, little is known about their location, function, or their scaffolding molecules during unconventional sexual proliferative stages. Using a combination of super-resolution microscopy, mass spectrometry, omics and live-cell fluorescence imaging, we set out to investigate the contribution of the atypical Aurora paralog ARK2 to proliferative sexual stages using rodent malaria model Plasmodium berghei. We find that ARK2 primarily localises to the spindle apparatus associated with kinetochores during both mitosis and meiosis. Interactomics and co-localisation studies reveal a unique ARK2 scaffold at the spindle including the microtubule plus end-binding protein EB1 and lacking some other conserved molecules. Gene function studies indicate complementary functions of ARK2 and EB1 in driving endomitotic divisions and thereby parasite transmission. Our discovery of a novel Aurora spindle scaffold underlines the emerging flexibility of molecular networks to rewire and drive unconventional mechanisms of chromosome segregation in the malaria parasite Plasmodium.