RESUMO
Multiple rounds of DNA replication take place in various stages of the life cycle in the human malaria parasite Plasmodium falciparum. Previous bioinformatics analysis has shown the presence of putative Autonomously Replicating Sequence (ARS) like sequences in the Plasmodium genome. However, the actual sites and frequency of replication origins in the P. falciparum genome based on experimental data still remain elusive. Minichromosome maintenance (MCM) proteins are recruited by the Origin recognition complex (ORC) to the origins of replication in eukaryotes including P. falciparum. We used PfMCM6 for chromatin immunoprecipitation followed by sequencing (ChIP-seq) in the quest for identification of putative replication origins in the parasite. PfMCM6 DNA binding sites annotation revealed high enrichment at exon regions. This is contrary to higher eukaryotes that show an inclination of origin sites towards transcriptional start sites. ChIP-seq results were further validated by ChIP-qPCR results as well as nascent strand abundance assay at the selected PfMCM6 enriched sites that also showed preferential binding of PfORC1 suggesting potential of these sites as origin sites. Further, PfMCM6 ChIP-seq data showed a positive correlation with previously published histone H4K8Ac genome-wide binding sites but not with H3K9Ac sites suggesting epigenetic control of replication initiation sites in the parasites. Overall, our data show the genome-wide distribution of PfMCM6 binding sites with their potential as replication origins in this deadly human pathogen that not only broadens our knowledge of parasite DNA replication and its unique biology, it may help to find new avenues for intervention processes.
Assuntos
Malária Falciparum , Parasitos , Animais , Humanos , Plasmodium falciparum/genética , Parasitos/genética , Parasitos/metabolismo , Replicação do DNA/genética , Sítios de Ligação , Malária Falciparum/genética , Cromossomos/metabolismo , Componente 6 do Complexo de Manutenção de Minicromossomo/genética , Componente 6 do Complexo de Manutenção de Minicromossomo/metabolismoRESUMO
Over the last decades, novel methods have been developed to study the role of chromosome positioning within the nucleus may play in gene regulation. Established proximity ligation-based chromosome conformation capture (3C) techniques such as Hi-C have revealed the existence of chromosome territories, functional nuclear landmarks, and topologically associating domains (TAPs) in most eukaryotic organisms. Adaptation of these methods in apicomplexan parasites has recently uncovered new aspects of 3D genome biology in virulence factors. Here, we describe the Hi-C protocol in the human malaria parasite, Plasmodium falciparum. This method can determine the genome organization in malaria parasites and its role in gene regulation and virulence.
Assuntos
Plasmodium falciparum , Cromossomos/genética , Genoma de Protozoário , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Malária , Plasmodium falciparum/genéticaRESUMO
Nail lichen planus is an inflammatory disorder of the nails with potential for significant cosmetic disfigurement and functional impairment. Nail manifestations may be isolated or appear concurrently with other forms of lichen planus. Longitudinal ridging is the most common clinical finding, but progressive disease may result in irreversible scarring (dorsal pterygium) or permanent nail loss (anonychia). Data on treatment are limited to retrospective studies and case reports. The mainstays of treatment are intralesional and intramuscular corticosteroid injections and oral retinoids. There is a need for randomized controlled trials on nail lichen planus to more rigorously assess efficacy and outcomes.
Assuntos
Líquen Plano , Doenças da Unha , Unhas Malformadas , Humanos , Líquen Plano/diagnóstico , Líquen Plano/tratamento farmacológico , Líquen Plano/epidemiologia , Doenças da Unha/diagnóstico , Doenças da Unha/tratamento farmacológico , Doenças da Unha/epidemiologia , Unhas , Estudos RetrospectivosRESUMO
Optic neuritis (ON) refers to conditions that involve inflammation of the optic nerve. Various autoantibodies have been found, which are associated with central nervous system inflammatory disorders and have provided much information about the immune targets and mechanisms that impact the prognosis, treatment, and recurrence of atypical ON. Therefore, neurologists and ophthalmologists together should work to find out clinical, laboratory, and imaging findings that may provide important clues to the etiology of atypical ON and its management. Various biomarkers have been identified to confirm and distinguish atypical optic neuritis from others. The purpose of this review is to present the current scenario of atypical ON and its clinical management.
Assuntos
Neurite Óptica , Autoanticorpos , Humanos , Glicoproteína Mielina-Oligodendrócito , Nervo Óptico , Neurite Óptica/diagnóstico , Neurite Óptica/etiologia , Neurite Óptica/terapia , PrognósticoRESUMO
Physicians and the general public may be underusing alcohol-based hand sanitizers based on the false perception that they are damaging to the skin. We describe the use of a screw-top toothpaste cap to approximate the necessary volume of alcohol-based sanitizer for adequate hand disinfection.
Assuntos
Etanol , Desinfecção das Mãos , Higienizadores de Mão , Humanos , Cremes DentaisAssuntos
Betacoronavirus , Dermatite de Contato , Etanol/farmacologia , Desinfecção das Mãos/métodos , Higienizadores de Mão/farmacologia , Sabões/farmacologia , Anti-Infecciosos Locais/farmacologia , Betacoronavirus/efeitos dos fármacos , Betacoronavirus/fisiologia , COVID-19 , Infecções por Coronavirus/prevenção & controle , Infecções por Coronavirus/virologia , Dermatite de Contato/etiologia , Dermatite de Contato/prevenção & controle , Transmissão de Doença Infecciosa/prevenção & controle , Emolientes/uso terapêutico , Higiene das Mãos/métodos , Humanos , Higroscópicos/uso terapêutico , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Pneumonia Viral/virologia , SARS-CoV-2RESUMO
Nucleosome assembly in P. falciparum could be the key process in maintaining its genomic integrity as DNA replicates more than once per cell cycle during several stages of its life cycle. Here, we report the functional characterization of P. falciparum chromatin assembly factor 1 (CAF1), which interacts with several proteins namely PfCAF2, Histones, PfHP1 and others. Consistent with the above findings, we demonstrate the presence of PfCAF1 at the telomeric repeat regions, central and subtelomeric var genes of multiple var gene family along with PfHP1. Further, we report the upregulation of PfCAF1 after treatment with genotoxic agents like MMS and HU. Together, these findings establish role of PfCAF1 in heterochromatin maintenance and as histone chaperone in nucleosome assembly and DNA damage repair.
Assuntos
Fator 1 de Modelagem da Cromatina/genética , Reparo do DNA/genética , Replicação do DNA/genética , DNA de Protozoário/genética , Nucleossomos/genética , Plasmodium falciparum/genéticaRESUMO
Malaria continues to be a major health problem globally. There is an urgent need to find new antimalarials. Acriflavine (ACF) is known as an antibacterial agent and more recently as an anticancer agent. Here, we report that ACF inhibits the growth of asexual stages of both chloroquine (CQ) sensitive and resistant strains of human malarial parasite, Plasmodium falciparum in vitro at nanomolar concentration. ACF clears the malaria infection in vivo from the bloodstreams of mice infected with Plasmodium berghei. Interestingly, ACF is accumulated only in the parasitized red blood cells (RBCs) and parasite specific transporters may have role in this specific drug accumulation. We further show that ACF impairs DNA replication foci formation in the parasites and affects the enzymatic activities of apicoplast specific Gyrase protein. We thus establish ACF as a potential antimalarial amidst the widespread incidences of drug resistant Plasmodium strains.
