98 research outputs found
Novel insights into telomere biology and virulence gene expression in plasmodium falciparum
No full textPlasmodium falciparum malaria is still one of the most preeminent and deadliest infectious diseases worldwide, imposing a tremendous health and economic burden on endemic countries. The high virulence of P. falciparum is mostly attributable to the expression of P. falciparum erythrocyte membrane protein 1 (PfEMP1) on the surface of infected red blood cells. PfEMP1 mediates intravascular parasite sequestration in vital organs, which contributes substantially to severe disease and death. Mutually exclusive transcription of the 60 var genes (encoding PfEMP1) and switching to formerly silenced variants results in antigenic variation and allows the parasite to efficiently evade host immune responses and to establish chronic infection.
Members of the var multigene family are predominantly positioned close to chromosome ends. Characteristically, these regions are transcriptionally inert and demarcated by the repressive histone mark H3K9me3 and the evolutionary conserved silencing factor P. falciparum heterochromatin protein 1 (PfHP1). It is believed that this specialised environment at chromosome ends generates a structural framework for the epigenetic control of var gene expression. Moreover, telomeres play a crucial role in preserving genome integrity by protecting chromosome ends from inappropriate fusion and recombination events, as well as in regulating telomere length.
However, we still lack a detailed functional understanding of the underlying molecular mechanisms that regulate Plasmodium chromosome end biology. During my PhD thesis, I tackled chromosome end biology from three different angles to improve our understanding of how virulence gene expression is regulated and how genome integrity is preserved.
In a first project I performed an in-depth functional analysis of the epigenetic silencing factor PfHP1 by generating an inducible loss-of-function mutant. We showed that upon PfHP1 depletion parasites display a complete breakdown of mutually exclusive var expression and antigenic variation. Intriguingly, we also found that over 50% of PfHP1-deprived parasites represented viable gametocytes that complete sexual development up to stage V maturity. This high conversion rate was linked to the targeted de-repression of the ap2-g locus that codes for the ApiAP2 transcription factor AP2-G, which is essential for gametocyte conversion. Thus, our data unveiled PfHP1 not only as a master regulator of variegated expression of exported virulence factors, but also as a crucial factor in the regulation of sexual cell differentiation.
In a second project I aimed at the functional characterisation of the chromosome-end associated protein PfSIP2, which was shown to specifically interact with SPE2 elements in subtelomeric regions. In-depth analysis of the expression profile of endogenous PfSIP2 revealed that this protein is only expressed during a very narrow time window of approximately 10hrs in late stage parasites, which coincides with intra-erythrocytic schizogony. Genome-wide ChIP-Seq experiments confirmed the exclusive binding of endogenous PfSIP2 to subtelomeric SPE2 landmarks in upsB var promoter regions and subtelomeric non-coding regions. Surprisingly, however, neither phenotypic changes nor differential gene expression were observed in a conditional PfSIP2-loss-of-function mutant and hence this approach didn’t uncover novel insights into the function of this ApiAP2 factor.
In a third project I aimed at the identification of the telomere repeat-binding factor (TRF) in P. falciparum. Although TRFs are highly conserved and play essential roles in preserving chromosome integrity and regulating chromosome length in model eukaryotes, so far no TRF homologue has been found in the malaria parasites. My work reports about the successful de novo identification of the P. falciparum telomere repeat-binding protein (PfTRF). Intriguingly, this protein appears to be evolutionary distinct from TRFs in other eukaryotes as it binds to telomere repeat DNA via a C-terminal C2H2-type zinc finger domain instead of a MYB domain. Genome-wide mapping by ChIP-Seq experiments not only confirmed that PfTRF indeed binds to all chromosome termini in vivo, but as well revealed an unexpected second binding hotspot at telomere repeat-like sequences found in subtelomeric var gene promoters. A comprehensive characterisation of PfTRF using a conditional loss-of-function mutant identified essential roles for this protein in mitotic cell cycle progression and telomere length regulation. Hence, our findings provide important new insight into mechanisms underlying genome maintenance and possibly virulence gene silencing in P. falciparum. They further suggest that malaria parasites employ an evolutionary divergent molecular complex to preserve telomere function.
In summary, my results provide important new and detailed understanding of the molecular processes involved in genome maintenance, virulence gene expression and sexual conversion in P. falciparum, processes that are highly relevant for malaria pathogenesis, parasite viability and malaria transmission. I am confident that these findings have important implications for the development of intervention strategies targeting parasite propagation and transmission
Investigating the link between nutrient sensing and gametocyte formation in the malaria parasite Plasmodium falciparum
No full textMalaria is an infectious disease and causes over 600’000 deaths annually. To ensure host-to-host transmission, malaria parasites rely on specialized stages, called gametocytes. The formation of these sexual precursor cells is initiated by commitment of asexual blood stage parasites to the sexual differentiation pathway. Plasmodium falciparum, the most virulent of six parasite species infecting humans, employs nutrient sensing to adapt the rate of sexual commitment. The parasite monitors the levels of the host-derived lipid lysophosphatidylcholine (lysoPC) to control the epigenetically regu-lated expression of the transcription factor AP2-G, the master regulator of sexual commitment. The molecular mechanisms linking lysoPC sensing to AP2-G expression, however, are poorly under-stood. In this PhD project, I aimed at identifying factors linking nutrient sensing and sexual commit-ment in P. falciparum. To this end, I investigated the effect of a set of chemical compounds and 12 selected genes on sexual commitment rates. In a first study, I assessed the effect of drug treatment on sexual commitment rates using a high content imaging-based assay to clarify the longstanding question of whether antimalarial drug treatment increases gametocyte formation. By screening a comprehensive set of pharmaceuticals using both drug sensitive and drug resistant parasite strains, we show that drug treatment indeed can increase sexual commitment rates, but only rarely results in a net increase in gametocyte production. Our results suggest that general stress, rather than drug-specific activities, promotes sexual commitment. This finding was crucial to interpret the results of a second study, in which we screened compounds of inhibitor libraries to identify molecules influenc-ing sexual commitment. We then employed mass spectrometry-based cellular thermal shift assays (MS-CETSA) to identify the cellular target of selected hit compounds. Thereby, we identified high-confidence candidate targets and assessed their role during sexual commitment using reverse genet-ics approaches. We found indication for an involvement of cyclic adenosine monophosphate (cAMP)-dependent signaling and protein kinase A (PKA) in regulating commitment to gametocyte formation. Based on reverse genetics experiments and chemical perturbation assays, we hypothesize that PKA acts as a repressor of AP2-G expression under lysoPC-free conditions and thus links nutri-ent sensing to the epigenetic regulation of AP2-G. However, more experiments are required to con-firm this hypothesis. In a third project, we assessed the function the FK506-binding protein 35 (FKBP35) – another putative target of a commitment-inducing compound – by combining reverse genetics with transcriptional and proteomic profiling. While we did not find evidence for a role in sexual commitment, we show that limiting FKBP35 levels are lethal to P. falciparum and result in a delayed death-like phenotype that is characterized by defective ribosome homeostasis and stalled protein synthesis. Our data furthermore suggest that the antiplasmodial activity of the well-characterized FKBP inhibitor FK506 is independent of FKBP35, which has implications for the de-velopment of FK506-derived molecules as antimicrobial drugs. In summary, this thesis offers a test-able model to further investigate the link between nutrient sensing and sexual commitment and pro-vides new insights into the function of FKBP35
Botulinum toxin (BoNT) in the correction of mimic wrinkles - the most common complications
No full textSzwed Monika, Szwed Jakub, Dzikowski Michał. Botulinum toxin (BoNT) in the correction of mimic wrinkles - the most common complications. Journal of Education, Health and Sport. 2022;12(8):714-721. eISSN 2391-8306. DOI http://dx.doi.org/10.12775/JEHS.2022.12.08.072
https://apcz.umk.pl/JEHS/article/view/JEHS.2022.12.08.072
https://zenodo.org/record/7015574
The journal has had 40 points in Ministry of Education and Science of Poland parametric evaluation. Annex to the announcement of the Minister of Education and Science of December 21, 2021. No. 32343.
Has a Journal's Unique Identifier: 201159. Scientific disciplines assigned: Physical Culture Sciences (Field of Medical sciences and health sciences); Health Sciences (Field of Medical Sciences and Health Sciences).
Punkty Ministerialne z 2019 - aktualny rok 40 punktów. Załącznik do komunikatu Ministra Edukacji i Nauki z dnia 21 grudnia 2021 r. Lp. 32343. Posiada Unikatowy Identyfikator Czasopisma: 201159.
Przypisane dyscypliny naukowe: Nauki o kulturze fizycznej (Dziedzina nauk medycznych i nauk o zdrowiu); Nauki o zdrowiu (Dziedzina nauk medycznych i nauk o zdrowiu).
© The Authors 2022;
This article is published with open access at Licensee Open Journal Systems of Nicolaus Copernicus University in Torun, Poland
Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author (s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non commercial license Share alike.
(http://creativecommons.org/licenses/by-nc-sa/4.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited.
The authors declare that there is no conflict of interests regarding the publication of this paper.
Received: 05.08.2022. Revised: 07.08.2022. Accepted: 22.08.2022.
Botulinum toxin (BoNT) in the correction of mimic wrinkles - the most common complications
Monika Szwed 1, Jakub Szwed 2, Michał Dzikowski 3
1. Provincial Specialist Hospital of the name Stefan Cardinal Wyszyński, Aleja Kraśnicka 100, 20-718 Lublin
2. Department of Urology, Independent Public Healthcare Center in Lubartów, Cicha 14, 21-100 Lubartów
3. 1st Department of Psychiatry, Psychotherapy and Early Intervention, Medical University of Lublin, 20-439 Lublin, Poland
Monika Szwed
https://orcid.org/0000-0002-5711-2172 [email protected]
Provincial Specialist Hospital of the name Stefan Cardinal Wyszyński, Aleja Kraśnicka 100, 20-718 Lublin
Jakub Szwed
https://orcid.org/0000-0003-4480-4265 [email protected]
Department of Urology, Independent Public Healthcare Center in Lubartów, Cicha 14, 21-100 Lubartów
Michał Dzikowski
https://orcid.org/0000-0002-4252-7308 [email protected]
1st Department of Psychiatry, Psychotherapy and Early Intervention, Medical University of Lublin, 20-439 Lublin, Poland
Abstract:
Introduction and purpose
Botulinum toxin (BoNT) products are commonly used to treat muscle spasms such as cervical dystonia as well as to treat expression lines. Serotype A of botulinum toxin is the strongest and is used in aesthetic medicine procedures. It provides predictable results while having few side effects. Nevertheless, complications may occur, such as: ptosis of the upper eyelid, drooping eyebrows, ectropia, double vision, xerophthalmia, falling corners of the mouth, dysphagia, hoarseness, local swelling, erythema, bruising, pain at the injection site, asymmetry.
The aim of the study is to discuss the most common complications after injection of the botulin toxin in the correction of mimic wrinkles.
Description of the state of knowledge
BoNT is a neurotoxin that acts on the neuromuscular junctions, inhibits the release of acetylcholine, consequently causing temporary chemical denervation. Muscle function begins to return approximately 3 months after injection and fully returns after 6 months. Comparison of clinical trials of botulinum toxin type A in aesthetic allowed for the quantification of the frequency of adverse effects: drooping eyelids (2.5%), drooping eyebrows (3.1%), disturbed eye sensation (3%) and lip asymmetry (6.9%). Complications after cosmetic botulinum toxin injections are rare, and those that do occur are usually mild and transient. These complications are technique dependent; the incidence decreases as the injection ability improves.
Summary
Side effects are rare, nevertheless, thorough knowledge of the patient's anatomy, medical history, possible complications related to the specific product and site of administration, and close monitoring are essential for safe, effective treatment and the achievement of satisfactory results.
Key-words: botulinum toxin, BoNT, wrinkles, aesthetic medicin
Variant Gene Expression and Antigenic Variation by Malaria Parasites
No full text Malaria is a significant threat throughout the developing world. Among the most fascinating aspects of the protozoan parasites responsible for this disease are the methods they employ to avoid the immune system and perpetuate chronic infections. Key among these is antigenic variation: By systematically altering antigens that are displayed to the host's immune system, the parasite renders the adaptive immune response ineffective. For Plasmodium falciparum, the species responsible for the most severe form of human malaria, this process involves a complicated molecular mechanism that results in continuously changing patterns of variant-antigen-encoding gene expression. Although many features of this process remain obscure, significant progress has been made in recent years to decipher various molecular aspects of the regulatory cascade that causes chronic infection. </jats:p
Mutually exclusive expression of virulence genes by malaria parasites is regulated independently of antigen production.
No full textThe primary virulence determinant of Plasmodium falciparum malaria parasite-infected cells is a family of heterogeneous surface receptors collectively referred to as PfEMP1. These proteins are encoded by a large, polymorphic gene family called var. The family contains approximately 60 individual genes, which are subject to strict, mutually exclusive expression, with the single expressed var gene determining the antigenic, cytoadherent, and virulence phenotype of the infected cell. The mutually exclusive expression pattern of var genes is imperative for the parasite's ability to evade the host's immune response and is similar to the process of "allelic exclusion" described for mammalian Ig and odorant receptor genes. In mammalian systems, mutually exclusive expression is ensured by negative feedback inhibition mediated by production of a functional protein. To investigate how expression of the var gene family is regulated, we have created transgenic lines of parasites in which expression of individual var loci can be manipulated. Here we show that no such negative feedback system exists in P. falciparum and that this process is dependent solely on the transcriptional regulatory elements immediately adjacent to each gene. Transgenic parasites that are selected to express a var gene in which the PfEMP1 coding region has been replaced by a drug-selectable marker silence all other var genes in the genome, thus effectively knocking out all PfEMP1 expression and indicating that the modified gene is still recognized as a member of the var gene family. Mutually exclusive expression in P. falciparum is therefore regulated exclusively at the level of transcription, and a functional PfEMP1 protein is not necessary for viability or for proper gene regulation in cultured parasites
In situ simulation training in First Aid. Pilot study. First aid in a dangerous workplace
No full textWitkowski Grzegorz, Padała Olga, Dzikowski Wojciech, Naylor Katarzyna, Domańska-Glonek Ewa, Torres Anna, Torres Kamil. In situ simulation training in First Aid. Pilot study. First aid in a dangerous workplace. Journal of Education, Health and Sport. 2017;7(4):435-446. eISSN 2391-8306. DOI http://dx.doi.org/10.5281/zenodo.495774
http://ojs.ukw.edu.pl/index.php/johs/article/view/4390
The journal has had 7 points in Ministry of Science and Higher Education parametric evaluation. Part B item 1223 (26.01.2017).
1223 Journal of Education, Health and Sport eISSN 2391-8306 7
© The Author (s) 2017;
This article is published with open access at Licensee Open Journal Systems of Kazimierz Wielki University in Bydgoszcz, Poland
Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium,
provided the original author(s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License
(http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited.
This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted, non commercial
use, distribution and reproduction in any medium, provided the work is properly cited.
The authors declare that there is no conflict of interests regarding the publication of this paper.
Received: 25.03.2017. Revised 27.03.2017. Accepted: 07.04.2017.
In situ simulation training in First Aid. Pilot study. First aid in a dangerous workplace
Grzegorz Witkowski
Department of Didactics and Medical Simulation, Chair of Human Anatomy, Medical University of Lublin, Poland
Olga Padała
Students' Scientific Association of Medical Simulation, Medical University of Lublin, Poland
Wojciech Dzikowski
Department of Didactics and Medical Simulation, Chair of Human Anatomy, Medical University of Lublin, Poland
Katarzyna Naylor
Department of Didactics and Medical Simulation, Chair of Human Anatomy, Medical University of Lublin, Poland
Ewa Domańska-Glonek
Department of Didactics and Medical Simulation, Chair of Human Anatomy, Medical University of Lublin, Poland
Anna Torres
Laboratory of Biostructure, Chair of Human Anatomy, Medical University of Lublin, Poland
Kamil Torres
Department of Didactics and Medical Simulation, Chair of Human Anatomy, Medical University of Lublin, Poland
Abstract
Purpose
The aim of the study was to evaluate the newly develop course prepared for the employees working in the forest and mountain environment
Methodology
31 people participated in the course. They were employees of Roztocze National Park and the Forestry Commission Lutowiska. A diagnostic survey was implemented in a form of a questionnaire. The respondents were provided with two original questionnaires and a telephone survey. Surveys were anonymous and voluntary.
Findings
The average assessment of First Aid knowledge before the workshop was 2.48 and majority of participants assesed First Aid as difficult. After the workshop, the respondents assessed the knowledge on average as 3.87 and as much as 58% declared that definitely would provide First Aid to a stranger; 81% to a close person. Over 80% of respondents noticed the need of regular training in First Aid.
Research implication
The analysis showed that regular improvement of First Aid skills is required by the participants. The training should be adjusted to the group’s needs in terms of the program, teaching techniques and the place of training. There is a need to implement such training on a wider scale among forestry and mountain workers.
Originality
Uncovering the gaps in First Aid training in mountain and forest workers in their professional training.
Key words: First Aid, foresters, battlefield medicine, occupational exposure, health and safety rule
Variable switching rates of malaria virulence genes are associated with chromosomal position
No full textAntigenic variation in Plasmodium falciparum malaria is mediated by transcriptional switches between different members of the multicopy var gene family. Each var gene encodes a member of a group of heterogeneous surface proteins collectively referred to as PfEMP1. Mutually exclusive expression ensures that an individual parasite only transcribes a single var gene at a time. In this work we studied var gene switching to determine if transcriptional switches favour expression of particular subgroups of var genes and if var gene activation within a clonal population of parasites follows a predetermined order. We show that in clonal parasite populations, expression of var genes located in the central regions of chromosomes is remarkably stable and that they rarely undergo transcriptional switches in the absence of selection. In contrast, parasites expressing subtelomerically located var genes readily switched to alternative var loci. We confirmed these observations by generating transgenic parasites carrying drug selectable markers in subtelomeric and central var loci and monitoring switching after release from selection. Our data show that different var genes have different intrinsic switching rates that correlate with chromosomal location, and that there is no predetermined order of expression.</p
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