RESUMO
Mechanisms of transcriptional control in malaria parasites are still not fully understood. The positioning patterns of G-quadruplex (G4) DNA motifs in the parasite's AT-rich genome, especially within the var gene family which encodes virulence factors, and in the vicinity of recombination hotspots, points towards a possible regulatory role of G4 in gene expression and genome stability. Here, we carried out the most comprehensive genome-wide survey, to date, of G4s in the Plasmodium falciparum genome using G4Hunter, which identifies G4 forming sequences (G4FS) considering their G-richness and G-skewness. We show an enrichment of G4FS in nucleosome-depleted regions and in the first exon of var genes, a pattern that is conserved within the closely related Laverania Plasmodium parasites. Under G4-stabilizing conditions, i.e., following treatment with pyridostatin (a high affinity G4 ligand), we show that a bona fide G4 found in the non-coding strand of var promoters modulates reporter gene expression. Furthermore, transcriptional profiling of pyridostatin-treated parasites, shows large scale perturbations, with deregulation affecting for instance the ApiAP2 family of transcription factors and genes involved in ribosome biogenesis. Overall, our study highlights G4s as important DNA secondary structures with a role in Plasmodium gene expression regulation, sub-telomeric recombination and var gene biology.
Assuntos
Quadruplex G , Malária/genética , Motivos de Nucleotídeos/genética , Plasmodium falciparum/genética , Aminoquinolinas/farmacologia , Animais , Regulação da Expressão Gênica/efeitos dos fármacos , Genoma/efeitos dos fármacos , Humanos , Malária/tratamento farmacológico , Malária/parasitologia , Ácidos Picolínicos/farmacologia , Plasmodium falciparum/patogenicidade , Regiões Promotoras Genéticas/genética , Ribossomos/efeitos dos fármacos , Ribossomos/genéticaRESUMO
Guanine-quadruplexes (G4s) are non-canonical DNA structures that can regulate key biological processes such as transcription, replication and telomere maintenance in several organisms including eukaryotes, prokaryotes and viruses. Recent reports have identified the presence of G4s within the AT-rich genome of Plasmodium falciparum, the protozoan parasite causing malaria. In Plasmodium, potential G4-forming sequences (G4FS) are enriched in the telomeric and sub-telomeric regions of the genome where they are associated with telomere maintenance and recombination events within virulence genes. However, there is a little understanding about the biological role of G4s and G4-binding proteins. Here, we provide the first snapshot of G4-interactome in P. falciparum using DNA pull-down assay followed by LC-MS/MS. Interestingly, we identified ~24 potential G4-binding proteins (G4-BP) that bind to a stable G4FS (AP2_G4). Furthermore, we characterised the role of G-strand binding protein 2 (PfGBP2), a putative telomere-binding protein in P. falciparum. We validated the interaction of PfGBP2 with G4 in vitro as well as in vivo. PfGBP2 is expressed throughout the intra-erythrocytic developmental cycle and is essential for the parasites in the presence of G4-stabilising ligand, pyridostatin. Gene knockout studies showed the role of PfGBP2 in the expression of var genes. Taken together, this study suggests that PfGBP2 is a bona fide G4-binding protein, which is likely to be involved in the regulation of G4-related functions in these malarial parasites. In addition, this study sheds light on this understudied G4 biology in P. falciparum.
Assuntos
Quadruplex G , Proteínas de Ligação ao GTP/genética , Proteínas de Ligação ao GTP/metabolismo , Plasmodium falciparum/genética , Proteínas de Transporte , Cromatografia Líquida , Humanos , Plasmodium falciparum/metabolismo , Regiões Promotoras Genéticas , Ligação Proteica , Espectrometria de Massas em TandemRESUMO
BACKGROUND: Informed consent prior to nursing care procedures is an established principle which acknowledges the right of the patient to authorise what is done to him or her; consent prior to nursing care should not be assumed. Nursing care procedures have the potential to be unwanted by the patient and hence require an appropriate form of authorisation that takes into consideration the relationship between the nurse and patient and the ongoing nature of care delivery. RESEARCH QUESTION: How do nurses obtain consent from patients prior to nursing care?. DESIGN: Critical incident technique and the collection of critical happenings. PARTICIPANTS: 17 participants who were all qualified nurses took part in in-depth interviews. ETHICAL CONSIDERATIONS: Ethical approval was obtained from the university ethics committee. FINDINGS: Information giving is a key component prior to nursing care procedures. Nurses provide information to patients as a routine aspect of care delivery, and do so even when the patient is unable to communicate themselves. Whilst some participants described how information giving might be rushed or overlooked at times, it is clearly an established part of nursing care and is provided to ensure the patient knows what to expect when care is delivered. What is less clear is the extent to which information is given in order to seek the consent - rather than merely inform the patient - about nursing care. CONCLUSION: Implied consent is often an appropriate way in which consent is obtained prior to nursing care procedures. It takes into account the ongoing care provision and the relationship that exists between the nurse and patient. However implied consent should not be assumed. Nurses need to ensure that information is given not only to inform the patient about a procedure but to enable the patient to give his or her consent and to find an alternative way forward if the patient withholds their consent.
Assuntos
Enfermeiras e Enfermeiros , Cuidados de Enfermagem , Feminino , Humanos , Consentimento Livre e Esclarecido , Masculino , Princípios MoraisRESUMO
Antimicrobial peptides (AMPs) are known to have family-specific sequence composition, which can be mined for discovery and design of AMPs. Here, we present CAMPR3; an update to the existing CAMP database available online at www.camp3.bicnirrh.res.in. It is a database of sequences, structures and family-specific signatures of prokaryotic and eukaryotic AMPs. Family-specific sequence signatures comprising of patterns and Hidden Markov Models were generated for 45 AMP families by analysing 1386 experimentally studied AMPs. These were further used to retrieve AMPs from online sequence databases. More than 4000 AMPs could be identified using these signatures. AMP family signatures provided in CAMPR3 can thus be used to accelerate and expand the discovery of AMPs. CAMPR3 presently holds 10247 sequences, 757 structures and 114 family-specific signatures of AMPs. Users can avail the sequence optimization algorithm for rational design of AMPs. The database integrated with tools for AMP sequence and structure analysis will be a valuable resource for family-based studies on AMPs.
Assuntos
Anti-Infecciosos/química , Bases de Dados de Produtos Farmacêuticos , Peptídeos/química , Peptídeos/farmacologia , Sequência de Aminoácidos , Anti-Infecciosos/farmacologia , Descoberta de DrogasRESUMO
A new mono-hydroxy acetylated sterol derivative: 12ß-hydroxy-3ß, 15α, 16ß-triacetoxy-cholest-5-en-7-one (halymeniaol) (1), and cholesterol (2) were isolated from the marine red alga Halymenia floresii. The structure of the compound 1 (halymeniaol) was established from its spectral data, derived from HRMS/MS and 2D NMR. Compound 1 exhibited growth inhibitory activity against chloroquine-resistant Plasmodium falciparum 3D7 strain with an IC50 of 3.0 µM.
Assuntos
Antimaláricos/isolamento & purificação , Antimaláricos/farmacologia , Rodófitas/química , Esteróis/isolamento & purificação , Esteróis/farmacologia , Antimaláricos/química , Colesterol/análogos & derivados , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Plasmodium falciparum/efeitos dos fármacos , Esteróis/químicaRESUMO
Condensin I is a pentameric complex that regulates the mitotic chromosome assembly in eukaryotes. The kleisin subunit CAP-H of the condensin I complex acts as a linchpin to maintain the structural integrity and loading of this complex on mitotic chromosomes. This complex is present in all eukaryotes and has recently been identified in Plasmodium spp. However, how this complex is assembled and whether the kleisin subunit is critical for this complex in these parasites is yet to be explored. To examine the role of PfCAP-H during cell division within erythrocytes, we generated an inducible PfCAP-H knockout parasite. We find that PfCAP-H is dynamically expressed during mitosis with the peak expression at the metaphase plate. PfCAP-H interacts with PfCAP-G and is a non-SMC member of the condensin I complex. Notably, the absence of PfCAP-H does not alter the expression of PfCAP-G but affects its localization at the mitotic chromosomes. While mitotic spindle assembly is intact in PfCAP-H deficient parasites, duplicated centrosomes remain clustered over the mass of unsegmented nuclei with failed karyokinesis. This failure leads to the formation of an abnormal nuclear mass, while cytokinesis occurs normally. Altogether, our data suggest that PfCAP-H plays a crucial role in maintaining the structural integrity of the condensin I complex on the mitotic chromosomes and is essential for the asexual development of malarial parasites.
RESUMO
Condensin I is a pentameric complex that regulates the mitotic chromosome assembly in eukaryotes. The kleisin subunit CAP-H of the condensin I complex acts as a linchpin to maintain the structural integrity and loading of this complex on mitotic chromosomes. This complex is present in all eukaryotes and has recently been identified in Plasmodium spp. However, how this complex is assembled and whether the kleisin subunit is critical for this complex in these parasites are yet to be explored. To examine the role of PfCAP-H during cell division within erythrocytes, we generated an inducible PfCAP-H knockout parasite. We find that PfCAP-H is dynamically expressed during mitosis with the peak expression at the metaphase plate. PfCAP-H interacts with PfCAP-G and is a non-SMC member of the condensin I complex. Notably, the absence of PfCAP-H does not alter the expression of PfCAP-G but affects its localization at the mitotic chromosomes. While mitotic spindle assembly is intact in PfCAP-H-deficient parasites, duplicated centrosomes remain clustered over the mass of unsegmented nuclei with failed karyokinesis. This failure leads to the formation of an abnormal nuclear mass, while cytokinesis occurs normally. Altogether, our data suggest that PfCAP-H plays a crucial role in maintaining the structural integrity of the condensin I complex on the mitotic chromosomes and is essential for the asexual development of malarial parasites. IMPORTANCE: Mitosis is a fundamental process for Plasmodium parasites, which plays a vital role in their survival within two distinct hosts-human and Anopheles mosquitoes. Despite its great significance, our comprehension of mitosis and its regulation remains limited. In eukaryotes, mitosis is regulated by one of the pivotal complexes known as condensin complexes. The condensin complexes are responsible for chromosome condensation, ensuring the faithful distribution of genetic material to daughter cells. While condensin complexes have recently been identified in Plasmodium spp., our understanding of how this complex is assembled and its precise functions during the blood stage development of Plasmodium falciparum remains largely unexplored. In this study, we investigate the role of a central protein, PfCAP-H, during the blood stage development of P. falciparum. Our findings reveal that PfCAP-H is essential and plays a pivotal role in upholding the structure of condensin I and facilitating karyokinesis.
Assuntos
Adenosina Trifosfatases , Divisão do Núcleo Celular , Proteínas de Ligação a DNA , Mitose , Plasmodium falciparum , Humanos , Adenosina Trifosfatases/metabolismo , Adenosina Trifosfatases/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/genética , Eritrócitos/parasitologia , Técnicas de Inativação de Genes , Complexos Multiproteicos/metabolismo , Complexos Multiproteicos/genética , Plasmodium falciparum/genética , Plasmodium falciparum/metabolismo , Plasmodium falciparum/fisiologia , Plasmodium falciparum/crescimento & desenvolvimento , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/genética , Divisão do Núcleo Celular/genéticaRESUMO
Globally, more than 1 billion people with disabilities are disproportionately and differentially at risk from the climate crisis. Yet there is a notable absence of climate policy, programming, and research at the intersection of disability and climate change. Advancing climate justice urgently requires accelerated disability-inclusive climate action. We present pivotal research recommendations and guidance to advance disability-inclusive climate research and responses identified by a global interdisciplinary group of experts in disability, climate change, sustainable development, public health, environmental justice, humanitarianism, gender, Indigeneity, mental health, law, and planetary health. Climate-resilient development is a framework for enabling universal sustainable development. Advancing inclusive climate-resilient development requires a disability human rights approach that deepens understanding of how societal choices and actions-characterised by meaningful participation, inclusion, knowledge diversity in decision making, and co-design by and with people with disabilities and their representative organisations-build collective climate resilience benefiting disability communities and society at large while advancing planetary health.
Assuntos
Pessoas com Deficiência , Resiliência Psicológica , Humanos , Direitos Humanos , Saúde Mental , Mudança ClimáticaRESUMO
Microscopic examination of blood smears remains the gold standard for laboratory inspection and diagnosis of malaria. Smear inspection is, however, time-consuming and dependent on trained microscopists with results varying in accuracy. We sought to develop an automated image analysis method to improve accuracy and standardization of smear inspection that retains capacity for expert confirmation and image archiving. Here, we present a machine learning method that achieves red blood cell (RBC) detection, differentiation between infected/uninfected cells, and parasite life stage categorization from unprocessed, heterogeneous smear images. Based on a pretrained Faster Region-Based Convolutional Neural Networks (R-CNN) model for RBC detection, our model performs accurately, with an average precision of 0.99 at an intersection-over-union threshold of 0.5. Application of a residual neural network-50 model to infected cells also performs accurately, with an area under the receiver operating characteristic curve of 0.98. Finally, combining our method with a regression model successfully recapitulates intraerythrocytic developmental cycle with accurate lifecycle stage categorization. Combined with a mobile-friendly web-based interface, called PlasmoCount, our method permits rapid navigation through and review of results for quality assurance. By standardizing assessment of Giemsa smears, our method markedly improves inspection reproducibility and presents a realistic route to both routine lab and future field-based automated malaria diagnosis.
RESUMO
Malaria parasites can readily sense and adapt to environmental changes, thus making the control and eradication of this disease difficult. Molecular studies have unraveled a very tightly coordinated transcriptional machinery governed by complex regulatory mechanisms including chromatin modification and spatiotemporal compartmentalization. Histone modifying enzymes play key roles in the regulation of chromatin modification and gene expression, which are associated with cell cycle progression, antigenic variation and immune evasion. Here, we present a comprehensive review of the key regulators of the Plasmodium falciparum histone acetylome; histone acetyltransferases (HATs); and histone deacetylases (HDACs). We describe the genome-wide occurrence of HATs and HDACs in the P. falciparum genome and identify novel, as well as previously unclassified HATs. We re-confirm the presence of five known HDACs and identify, a novel putative HDAC. Interestingly, we identify several HATs and HDACs with unique and noncanonical domain combinations indicating their involvement in other associated functions. Moreover, the phylogenetic analyses of HATs and HDACs suggest that many of them are close to the prokaryotic systems and thus potential candidates for drug development. Our review deciphers the phylogeny of HATs and HDACs of the malaria parasite, investigates their role in drug-resistance generation, and highlights their potential as therapeutic targets.