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Journal of Reproductive Immunology Aug 2023Molecular communication between a pathogen and its host is crucial for a successful interplay. Extracellular vesicles (EVs) act as mediators for the delivery of... (Review)
Review
Molecular communication between a pathogen and its host is crucial for a successful interplay. Extracellular vesicles (EVs) act as mediators for the delivery of molecular signals among pathogens or between pathogens and the host. Toxoplasma gondii (T. gondii), an intracellular parasite with a worldwide presence, produces EVs itself, or induces the secretion of EVs from infected host cells potentially having capacities to modulate the host immune response. T. gondii infection is particularly important during pregnancy. Depending on the gestational age at the time of infection, the parasite can be transmitted through the placenta to the fetus, causing clinical complications such as jaundice, hepatosplenomegaly, chorioretinitis, cranioencephalic abnormalities, or even death. T. gondii infection is related to a pro-inflammatory immune response in both mother and fetus, which may enhance parasite transmission, but the implication of EV signaling in this process remains unclear. In this review, we summarize the current knowledge on EV release from T. gondii and its human host cells in regard to the immunological consequences and the passage through the placenta.
Topics: Pregnancy; Female; Humans; Toxoplasmosis; Toxoplasma; Host-Pathogen Interactions; Extracellular Vesicles; Placenta
PubMed: 37253287
DOI: 10.1016/j.jri.2023.103957 -
Journal of Microbiological Methods Jul 2024As data accumulate in GenBank, the difficulties of delineating species of Cryptosporidium based on nuclear small subunit ribosomal RNA (ssu rRNA) gene information alone... (Review)
Review
As data accumulate in GenBank, the difficulties of delineating species of Cryptosporidium based on nuclear small subunit ribosomal RNA (ssu rRNA) gene information alone becomes increasingly evident. Here, we summarize currently available evidence suggesting that several ssu rDNA sequences primarily referred to as Cryptosporidium suis (some of them from non-suid hosts) should be considered Cryptosporidium occultus.
Topics: Cryptosporidium; Cryptosporidiosis; Animals; DNA, Ribosomal; DNA, Protozoan; Humans; Phylogeny; Sequence Analysis, DNA
PubMed: 38777182
DOI: 10.1016/j.mimet.2024.106957 -
Biochemical Society Transactions Apr 2024Malaria, a vector borne disease, is a major global health and socioeconomic problem caused by the apicomplexan protozoan parasite Plasmodium. The parasite alternates... (Review)
Review
Malaria, a vector borne disease, is a major global health and socioeconomic problem caused by the apicomplexan protozoan parasite Plasmodium. The parasite alternates between mosquito vector and vertebrate host, with meiosis in the mosquito and proliferative mitotic cell division in both hosts. In the canonical eukaryotic model, cell division is either by open or closed mitosis and karyokinesis is followed by cytokinesis; whereas in Plasmodium closed mitosis is not directly accompanied by concomitant cell division. Key molecular players and regulatory mechanisms of this process have been identified, but the pivotal role of certain protein complexes and the post-translational modifications that modulate their actions are still to be deciphered. Here, we discuss recent evidence for the function of known proteins in Plasmodium cell division and processes that are potential novel targets for therapeutic intervention. We also identify key questions to open new and exciting research to understand divergent Plasmodium cell division.
Topics: Plasmodium; Cell Division; Animals; Humans; Malaria; Protozoan Proteins; Mitosis; Cytokinesis; Meiosis; Protein Processing, Post-Translational; Host-Parasite Interactions
PubMed: 38563493
DOI: 10.1042/BST20230403 -
Scientific Reports Sep 2023The phylum Apicomplexa comprises a large group of intracellular protozoan parasites. These microorganisms are known to infect a variety of vertebrate and invertebrate...
The phylum Apicomplexa comprises a large group of intracellular protozoan parasites. These microorganisms are known to infect a variety of vertebrate and invertebrate hosts, leading to significant medical and veterinary conditions such as toxoplasmosis, cryptosporidiosis, theileriosis, and eimeriosis. Despite their importance, comprehensive data on their diversity and distribution, especially in riverine environments, remain scant. To bridge this knowledge gap, we utilized next-generation high-throughput 18S rRNA amplicon sequencing powered by PacBio technology to explore the diversity and composition of the Apicomplexa taxa. Principal component analysis (PCA) and principal coordinate analysis (PCoA) indicated the habitat heterogeneity for the physicochemical parameters and the Apicomplexa community. These results were supported by PERMANOVA (P < 0.001), ANOSIM (P < 0.001), Cluster analysis, and Venn diagram. Dominant genera of Apicomplexa in inlet samples included Gregarina (38.54%), Cryptosporidium (32.29%), and Leidyana (11.90%). In contrast, outlet samples were dominated by Babesia, Cryptosporidium, and Theileria. While surface water samples revealed 16% and 8.33% relative abundance of Toxoplasma and Cryptosporidium, respectively. To our knowledge, the next-generation high throughput sequencing covered a wide range of parasites in Egypt for the first time, which could be useful for legislation of the standards for drinking water and wastewater reuse.
Topics: Humans; Cryptosporidium; Cryptosporidiosis; Babesia; High-Throughput Nucleotide Sequencing; Toxoplasma
PubMed: 37699953
DOI: 10.1038/s41598-023-40895-y -
Molecular Microbiology Apr 2024Apicomplexan parasites are aetiological agents of numerous diseases in humans and livestock. Functional genomics studies in these parasites enable the identification of... (Review)
Review
Apicomplexan parasites are aetiological agents of numerous diseases in humans and livestock. Functional genomics studies in these parasites enable the identification of biological mechanisms and protein functions that can be targeted for therapeutic intervention. Recent improvements in forward genetics and whole-genome screens utilising CRISPR/Cas technology have revolutionised the functional analysis of genes during Apicomplexan infection of host cells. Here, we highlight key discoveries from CRISPR/Cas9 screens in Apicomplexa or their infected host cells and discuss remaining challenges to maximise this technology that may help answer fundamental questions about parasite-host interactions.
Topics: Humans; Animals; CRISPR-Cas Systems; Genome; Apicomplexa; Parasites; Host-Parasite Interactions
PubMed: 38225194
DOI: 10.1111/mmi.15221 -
Transfusion-transmitted spp.: a changing landscape of epidemiology, regulation, and risk mitigation.Journal of Clinical Microbiology Oct 2023spp. are tick-borne parasites with a global distribution and diversity of vertebrate hosts. Over the next several decades, climate change is expected to impact humans,... (Review)
Review
spp. are tick-borne parasites with a global distribution and diversity of vertebrate hosts. Over the next several decades, climate change is expected to impact humans, vectors, and vertebrate hosts and change the epidemiology of . Although humans are dead-end hosts for tick-transmitted , human-to-human transmission of spp. from transfusion of red blood cells and whole blood-derived platelet concentrates has been reported. In most patients, transfusion-transmitted (TTB) results in a moderate-to-severe illness. Currently, in North America, most cases of TTB have been described in the United States. TTB cases outside North America are rare, but case numbers may change over time with increased recognition of babesiosis and as the epidemiology of is impacted by climate change. Therefore, TTB is a concern of microbiologists working in blood operator settings, as well as in clinical settings where transfusion occurs. Microbiologists play an important role in deploying blood donor screening assays in endemic regions, identifying changing risks for in non-endemic areas, investigating recipients of blood products for TTB, and drafting TTB policies and guidelines. In this review, we provide an overview of the clinical presentation and epidemiology of TTB. We identify approaches and technologies to reduce the risk of collecting blood products from -infected donors and describe how investigations of TTB are undertaken. We also describe how microbiologists in non-endemic regions can assess for changing risks of TTB and decide when to focus on laboratory-test-based approaches or pathogen reduction to reduce TTB risk.
Topics: Humans; United States; Babesia; Babesia microti; Blood Transfusion; Babesiosis; Blood Donors
PubMed: 37750699
DOI: 10.1128/jcm.01268-22 -
Frontiers in Immunology 2024Interferons (IFNs) are a family of cytokines with diverse functions in host resistance to pathogens and in immune regulation. Type II IFN, i.e. IFN-γ, is widely... (Review)
Review
Interferons (IFNs) are a family of cytokines with diverse functions in host resistance to pathogens and in immune regulation. Type II IFN, i.e. IFN-γ, is widely recognized as a major mediator of resistance to intracellular pathogens, including the protozoan . More recently, IFN-α/β, i.e. type I IFNs, and IFN-λ (type III IFN) have been identified to also play important roles during infections. This parasite is a widespread pathogen of humans and animals, and it is a model organism to study cell-mediated immune responses to intracellular infection. Its success depends, among other factors, on the ability to counteract the IFN system, both at the level of IFN-mediated gene expression and at the level of IFN-regulated effector molecules. Here, I review recent advances in our understanding of the molecular mechanisms underlying IFN-mediated host resistance and immune regulation during infections. I also discuss those mechanisms that has evolved to efficiently evade IFN-mediated immunity. Knowledge of these fascinating host-parasite interactions and their underlying signalling machineries is crucial for a deeper understanding of the pathogenesis of toxoplasmosis, and it might also identify potential targets of parasite-directed or host-directed supportive therapies to combat the parasite more effectively.
Topics: Humans; Animals; Toxoplasma; Interferons; Parasites; Immune Evasion; Interferon-gamma; Toxoplasmosis
PubMed: 38384452
DOI: 10.3389/fimmu.2024.1356216 -
How colonization bottlenecks, tissue niches, and transmission strategies shape protozoan infections.Trends in Parasitology Dec 2023Protozoan pathogens such as Plasmodium spp., Leishmania spp., Toxoplasma gondii, and Trypanosoma spp. are often associated with high-mortality, acute and chronic... (Review)
Review
Protozoan pathogens such as Plasmodium spp., Leishmania spp., Toxoplasma gondii, and Trypanosoma spp. are often associated with high-mortality, acute and chronic diseases of global health concern. For transmission and immune evasion, protozoans have evolved diverse strategies to interact with a range of host tissue environments. These interactions are linked to disease pathology, yet our understanding of the association between parasite colonization and host homeostatic disruption is limited. Recently developed techniques for cellular barcoding have the potential to uncover the biology regulating parasite transmission, dissemination, and the stability of infection. Understanding bottlenecks to infection and the in vivo tissue niches that facilitate chronic infection and spread has the potential to reveal new aspects of parasite biology.
Topics: Animals; Humans; Host-Parasite Interactions; Protozoan Infections; Parasites; Toxoplasma; Plasmodium
PubMed: 37839913
DOI: 10.1016/j.pt.2023.09.017 -
Proceedings of the National Academy of... Jan 2024Parasites and their hosts are engaged in reciprocal coevolution that balances competing mechanisms of virulence, resistance, and evasion. This often leads to host...
Parasites and their hosts are engaged in reciprocal coevolution that balances competing mechanisms of virulence, resistance, and evasion. This often leads to host specificity, but genomic reassortment between different strains can enable parasites to jump host barriers and conquer new niches. In the apicomplexan parasite , genetic exchange has been hypothesized to play a prominent role in adaptation to humans. The sexual lifecycle of the parasite provides a potential mechanism for such exchange; however, the boundaries of sex are currently undefined. To explore this experimentally, we established a model for genetic crosses. Drug resistance was engineered using a mutated phenylalanyl tRNA synthetase gene and marking strains with this and the previously used Neo transgene enabled selection of recombinant progeny. This is highly efficient, and genomic recombination is evident and can be continuously monitored in real time by drug resistance, flow cytometry, and PCR mapping. Using this approach, multiple loci can now be modified with ease. We demonstrate that essential genes can be ablated by crossing a Cre recombinase driver strain with floxed strains. We further find that genetic crosses are also feasible between species. Crossing a parasite of cattle and humans, and a mouse parasite resulted in progeny with a recombinant genome derived from both species that continues to vigorously replicate sexually. These experiments have important fundamental and translational implications for the evolution of and open the door to reverse- and forward-genetic analysis of parasite biology and host specificity.
Topics: Crosses, Genetic; Cryptosporidiosis; Cryptosporidium; Cryptosporidium parvum; Life Cycle Stages
PubMed: 38147547
DOI: 10.1073/pnas.2313210120 -
Current Opinion in Microbiology Jun 2024Apicomplexan and trypanosomatid parasites have evolved a wide range of post-transcriptional processes that allow them to replicate, differentiate, and transmit within... (Review)
Review
Apicomplexan and trypanosomatid parasites have evolved a wide range of post-transcriptional processes that allow them to replicate, differentiate, and transmit within and among multiple different tissue, host, and vector environments. In this review, we highlight the recent advances that point toward the regulatory potential of RNA modifications in mediating these processes on the coding and noncoding transcriptome throughout the life cycle of protozoan parasites. We discuss the recent technical advancements enabling the study of the 'epitranscriptome' and how parasites evolved RNA modification-mediated mechanisms adapted to their unique lifestyles.
Topics: RNA Processing, Post-Transcriptional; RNA, Protozoan; Animals; Apicomplexa; Transcriptome; Life Cycle Stages
PubMed: 38663181
DOI: 10.1016/j.mib.2024.102477