scholarly journals Generation of Transmission-Competent Human Malaria Parasites with Chromosomally-Integrated Fluorescent Reporters

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Kyle Jarrod McLean ◽  
Judith Straimer ◽  
Christine S. Hopp ◽  
Joel Vega-Rodriguez ◽  
Jennifer L. Small-Saunders ◽  
...  
Keyword(s):  
Life Cycle ◽  
Integration Site ◽  
Complex Life Cycle ◽  
Phenotypic Characterization ◽  
Malaria Parasites ◽  
Fluorescent Reporters ◽  
Genome Expression ◽  
Chemical Inhibitors ◽  
High Infection

Abstract Malaria parasites have a complex life cycle that includes specialized stages for transmission between their mosquito and human hosts. These stages are an understudied part of the lifecycle yet targeting them is an essential component of the effort to shrink the malaria map. The human parasite Plasmodium falciparum is responsible for the majority of deaths due to malaria. Our goal was to generate transgenic P. falciparum lines that could complete the lifecycle and produce fluorescent transmission stages for more in-depth and high-throughput studies. Using zinc-finger nuclease technology to engineer an integration site, we generated three transgenic P. falciparum lines in which tdtomato or gfp were stably integrated into the genome. Expression was driven by either stage-specific peg4 and csp promoters or the constitutive ef1a promoter. Phenotypic characterization of these lines demonstrates that they complete the life cycle with high infection rates and give rise to fluorescent mosquito stages. The transmission stages are sufficiently bright for intra-vital imaging, flow cytometry and scalable screening of chemical inhibitors and inhibitory antibodies.

scholarly journals Generation of Transgenic Human Malaria Parasites With Strong Fluorescence in the Transmission Stages

2018 ◽  
Author(s):  
Kyle J McLean ◽  
Judith Straimer ◽  
Christine S Hopp ◽  
Joel Vega-Rodriguez ◽  
Abhai Tripathi ◽  
...  
Keyword(s):  
Life Cycle ◽  
Integration Site ◽  
Complex Life Cycle ◽  
Phenotypic Characterization ◽  
Malaria Parasites ◽  
Genome Expression ◽  
High Infection ◽  
Parasite Plasmodium ◽  
Parasite Plasmodium Falciparum ◽  
Marker Free

Malaria parasites have a complex life cycle that includes specialized stages for transmission between their mosquito and human hosts. These stages are an understudied part of the lifecycle yet targeting them is an essential component of the effort to shrink the malaria map. The human parasite Plasmodium falciparum is responsible for the majority of deaths due to malaria. Our goal was to generate transgenic P. falciparum lines that could complete the lifecycle and produce fluorescent transmission stages for more in-depth and high-throughput studies. Using zinc-finger nuclease technology to engineer a marker-free integration site, we generated three transgenic P. falciparum lines in which tdtomato or gfp were stably integrated into the genome. Expression was driven by either stage-specific peg4 and csp promoters or the constitutive ef1a promoter. Phenotypic characterization of these lines demonstrates that they complete the life cycle with high infection rates and give rise to fluorescent mosquito stages. The transmission stages are sufficiently bright for intra-vital imaging, flow cytometry and scalable screening of chemical inhibitors and potentially inhibitory antibodies.

scholarly journals What functional genomics has taught us about transcriptional regulation in malaria parasites

2019 ◽  
Vol 18 (5) ◽  
pp. 290-301 ◽  
Author(s):  
Christa G Toenhake ◽  
Richárd Bártfai
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Life Cycle ◽  
Functional Genomics ◽  
Expression Patterns ◽  
Regulatory Elements ◽  
Complex Life Cycle ◽  
Malaria Parasites ◽  
Gene Regulatory

Abstract Malaria parasites are characterized by a complex life cycle that is accompanied by dynamic gene expression patterns. The factors and mechanisms that regulate gene expression in these parasites have been searched for even before the advent of next generation sequencing technologies. Functional genomics approaches have substantially boosted this area of research and have yielded significant insights into the interplay between epigenetic, transcriptional and post-transcriptional mechanisms. Recently, considerable progress has been made in identifying sequence-specific transcription factors and DNA-encoded regulatory elements. Here, we review the insights obtained from these efforts including the characterization of core promoters, the involvement of sequence-specific transcription factors in life cycle progression and the mapping of gene regulatory elements. Furthermore, we discuss recent developments in the field of functional genomics and how they might contribute to further characterization of this complex gene regulatory network.

scholarly journals Beyond triglyceride synthesis: the dynamic functional roles of MGAT and DGAT enzymes in energy metabolism

2009 ◽  
Vol 297 (1) ◽  
pp. E10-E18 ◽  
Author(s):  
Yuguang Shi ◽  
Dong Cheng
Keyword(s):  
Energy Homeostasis ◽  
Selective Inhibition ◽  
Phenotypic Characterization ◽  
Metabolic Complications ◽  
Physiological Functions ◽  
Functional Roles ◽  
Chemical Inhibitors ◽  
Intestinal Fat Absorption ◽  
Lipoprotein Assembly

Monoacyglycerol acyltransferases (MGATs) and diacylglycerol acyltransferases (DGATs) catalyze two consecutive steps of enzyme reactions in the synthesis of triacylglycerols (TAGs). The metabolic complexity of TAG synthesis is reflected by the presence of multiple isoforms of MGAT and DGAT enzymes that differ in catalytic properties, subcellular localization, tissue distribution, and physiological functions. MGAT and DGAT enzymes play fundamental roles in the metabolism of monoacylglycerol (MAG), diacylglycerol (DAG), and triacylglycerol (TAG) that are involved in many aspects of physiological functions, such as intestinal fat absorption, lipoprotein assembly, adipose tissue formation, signal transduction, satiety, and lactation. The recent progress in the phenotypic characterization of mice deficient in MGAT and DGAT enzymes and the development of chemical inhibitors have revealed important roles of these enzymes in the regulation of energy homeostasis and insulin sensitivity. Consequently, selective inhibition of MGAT or DGAT enzymes by synthetic compounds may provide novel treatment for obesity and its related metabolic complications.

scholarly journals Parasites are Particularly Problematic

2018 ◽  
Vol 2 ◽  
pp. e25604
Author(s):  
Susan Perkins
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Information Content ◽  
Definitive Host ◽  
Complex Life Cycle ◽  
Phylogenetic Study ◽  
Biodiversity Informatics ◽  
Malaria Parasites ◽  
Parasitic Organism

Although they are hyperdiverse and intensively studied, parasites present major challenges when it comes to phylogenetics, taxonomy, and biodiversity informatics. The collection of any parasitic organism entails the linking of at least two specimens - the parasite and the host. If the parasite has a complex life cycle, then this becomes further complicated by requiring the linking of three or more hosts, such as the parasite, its intermediate host (vector) and its definitive host(s). Parasites are sometimes collected as byproduct of another collection event and are not studied immediately - which has the potential to disconnect them further in terms of information content and continuity- and the converse if also common - parasites can be collected by parasitologists, who do not necessarily take host vouchers or incorporate host taxonomy, let alone other metadata for these events. Using the specific example of the malaria parasites (Order Haemosporida) I will present examples of the specific challenges that have accompanied the study of these parasites including issues of delimiting species, phylogenetic study, including genetic oddities that are unique to these organisms, and taxonomic quandries that we now find ourselves in, along with other problems with maintaining continuity of information in a group that is both diverse biologically and important medically.

scholarly journals Design and Synthesis of Novel Hybrid Molecules against Malaria

2015 ◽  
Vol 2015 ◽  
pp. 1-23 ◽  
Author(s):  
Melanie Lödige ◽  
Luisa Hiersch
Keyword(s):  
Life Cycle ◽  
Effective Treatment ◽  
Clinical Symptoms ◽  
Complex Life Cycle ◽  
Synthetic Approach ◽  
Transmission Cycle ◽  
Design And Synthesis ◽  
Hybrid Molecules ◽  
Multiple Stages

The effective treatment of malaria can be very complex: Plasmodium parasites develop in multiple stages within a complex life cycle between mosquitoes as vectors and vertebrates as hosts. For the full and effective elimination of parasites, an effective drug should be active against the earliest stages of the Plasmodium infection: liver stages (reduce the progress of the infection), blood stages (cure the clinical symptoms), and gametocytes (inhibit the transmission cycle). Towards this goal, here we report the design, the synthetic methodology, and the characterization of novel hybrid agents with combined activity against Plasmodium liver stages and blood stages and gametocytes. The divergent synthetic approach allows the access to differently linked primaquine-chloroquine hybrid templates in up to eight steps.

scholarly journals The ApiAP2 factor PfAP2-HC is an integral component of heterochromatin in the malaria parasite Plasmodium falciparum

2020 ◽  
Author(s):  
Eilidh Carrington ◽  
Roel H. M. Cooijmans ◽  
Dominique Keller ◽  
Christa G. Toenhake ◽  
Richárd Bártfai ◽  
...  
Keyword(s):  
Gene Expression ◽  
Plasmodium Falciparum ◽  
Life Cycle ◽  
Dna Binding ◽  
Regulation Of Gene Expression ◽  
Complex Life Cycle ◽  
Parasite Development ◽  
Specific Gene ◽  
Mosquito Vector ◽  
Malaria Parasites

AbstractMalaria parasites undergo a highly complex life cycle in the human host and the mosquito vector. The ApiAP2 family of sequence-specific DNA-binding proteins plays a dominant role in parasite development and life cycle progression. Of the ApiAP2 factors studied to date, most act as transcription factors regulating stage-specific gene expression. Here, we characterised a new ApiAP2 factor in Plasmodium falciparum (PF3D7_1456000) that we termed PfAP2-HC. Via detailed investigation of several single or double genetically engineered parasite lines, we demonstrate that PfAP2-HC specifically binds to heterochromatin throughout the genome. Intriguingly, PfAP2-HC does not bind DNA in vivo and recruitment of PfAP2-HC to heterochromatin is independent of its DNA-binding domain but strictly dependent on heterochromatin protein 1. Furthermore, our results suggest that PfAP2-HC functions neither in the regulation of gene expression nor in heterochromatin formation or maintenance. In summary, our findings reveal that PfAP2-HC constitutes a core component of heterochromatin in malaria parasites. They furthermore identify unexpected properties of ApiAP2 factors and suggest substantial functional divergence among the members of this important family of regulatory proteins.

scholarly journals Targeting SUMOylation in Plasmodium as a Potential Target for Malaria Therapy

2021 ◽  
Vol 11 ◽  
Author(s):  
Daffiny Sumam de Oliveira ◽  
Thales Kronenberger ◽  
Giuseppe Palmisano ◽  
Carsten Wrenger ◽  
Edmarcia Elisa de Souza
Keyword(s):  
Life Cycle ◽  
Molecular Mechanisms ◽  
Gene Expression Regulation ◽  
Public Health Problem ◽  
Complex Life Cycle ◽  
Cellular Functions ◽  
Cellular Mechanisms ◽  
Malaria Parasites ◽  
Malaria Therapy ◽  
Lysine Residues

Malaria is a parasitic disease that represents a public health problem worldwide. Protozoans of the Plasmodium genus are responsible for causing malaria in humans. Plasmodium species have a complex life cycle that requires post-translational modifications (PTMs) to control cellular activities temporally and spatially and regulate the levels of critical proteins and cellular mechanisms for maintaining an efficient infection and immune evasion. SUMOylation is a PTM formed by the covalent linkage of a small ubiquitin-like modifier protein to the lysine residues on the protein substrate. This PTM is reversible and is triggered by the sequential action of three enzymes: E1-activating, E2-conjugating, and E3 ligase. On the other end, ubiquitin-like-protein-specific proteases in yeast and sentrin-specific proteases in mammals are responsible for processing SUMO peptides and for deconjugating SUMOylated moieties. Further studies are necessary to comprehend the molecular mechanisms and cellular functions of SUMO in Plasmodium. The emergence of drug-resistant malaria parasites prompts the discovery of new targets and antimalarial drugs with novel mechanisms of action. In this scenario, the conserved biological processes regulated by SUMOylation in the malaria parasites such as gene expression regulation, oxidative stress response, ubiquitylation, and proteasome pathways, suggest PfSUMO as a new potential drug target. This mini-review focuses on the current understanding of the mechanism of action of the PfSUMO during the coordinated multi-step life cycle of Plasmodium and discusses them as attractive new target proteins for the development of parasite-specific inhibitors and therapeutic intervention toward malaria disease.

scholarly journals A DnaK Homolog in Myxococcus xanthus Is Involved in Social Motility and Fruiting Body Formation

1998 ◽  
Vol 180 (2) ◽  
pp. 218-224 ◽  
Author(s):  
Zhaomin Yang ◽  
Yongzhi Geng ◽  
Wenyuan Shi
Keyword(s):  
Life Cycle ◽  
Myxococcus Xanthus ◽  
Complex Life Cycle ◽  
Phenotypic Characterization ◽  
Fruiting Body Formation ◽  
Gram Negative ◽  
Body Formation ◽  
The Social ◽  
Cellular Aggregation ◽  
Social Motility

ABSTRACT Myxococcus xanthus is a gram-negative soil bacterium which exhibits a complex life cycle and social behavior. In this study, two developmental mutants of M. xanthus were isolated through Tn5 transposon mutagenesis. The mutants were found to be defective in cellular aggregation as well as in sporulation. Further phenotypic characterization indicated that the mutants were defective in social motility but normal in directed cell movements. Both mutations were cloned by a transposon-tagging method. Sequence analysis indicated that both insertions occurred in the same gene, which encodes a homolog of DnaK. Unlike the dnaK genes in other bacteria, this M. xanthus homolog appears not to be regulated by temperature or heat shock and is constitutively expressed during vegetative growth and under starvation. The defects of the mutants indicate that this DnaK homolog is important for the social motility and development of M. xanthus.

scholarly journals Heme A synthesis and CcO activity are essential for Trypanosoma cruzi infectivity and replication

2017 ◽  
Vol 474 (14) ◽  
pp. 2315-2332 ◽  
Author(s):  
Marcelo L. Merli ◽  
Brenda A. Cirulli ◽  
Simón M. Menéndez-Bravo ◽  
Julia A. Cricco
Keyword(s):  
Life Cycle ◽  
Trypanosoma Cruzi ◽  
Respiratory Chain ◽  
Complex Life Cycle ◽  
Enzymatic Reactions ◽  
Terminal Oxidase ◽  
Branched Respiratory Chain ◽  
Nutrients Availability ◽  
Respiratory Chain Activity

Trypanosoma cruzi, the causative agent of Chagas disease, presents a complex life cycle and adapts its metabolism to nutrients’ availability. Although T. cruzi is an aerobic organism, it does not produce heme. This cofactor is acquired from the host and is distributed and inserted into different heme-proteins such as respiratory complexes in the parasite's mitochondrion. It has been proposed that T. cruzi's energy metabolism relies on a branched respiratory chain with a cytochrome c oxidase-type aa3 (CcO) as the main terminal oxidase. Heme A, the cofactor for all eukaryotic CcO, is synthesized via two sequential enzymatic reactions catalyzed by heme O synthase (HOS) and heme A synthase (HAS). Previously, TcCox10 and TcCox15 (Trypanosoma cruzi Cox10 and Cox15 proteins) were identified in T. cruzi. They presented HOS and HAS activity, respectively, when they were expressed in yeast. Here, we present the first characterization of TcCox15 in T. cruzi, confirming its role as HAS. It was differentially detected in the different T. cruzi stages, being more abundant in the replicative forms. This regulation could reflect the necessity of more heme A synthesis, and therefore more CcO activity at the replicative stages. Overexpression of a non-functional mutant caused a reduction in heme A content. Moreover, our results clearly showed that this hindrance in the heme A synthesis provoked a reduction on CcO activity and, in consequence, an impairment on T. cruzi survival, proliferation and infectivity. This evidence supports that T. cruzi depends on the respiratory chain activity along its life cycle, being CcO an essential terminal oxidase.

Sign in / Sign up

Export Citation Format

Share Document