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Trends in Parasitology Feb 2024In malaria parasites, although post-translational modification of proteins with N-. O-, and C-glycosidic bond-linked glycans is limited, it is confined to relatively... (Review)
Review
In malaria parasites, although post-translational modification of proteins with N-. O-, and C-glycosidic bond-linked glycans is limited, it is confined to relatively fewer proteins in which the glycans are present at significant levels and may have important functions. Furthermore, several proteins are modified with glycosylphosphatidylinositols (GPIs) which represent the predominant glycan synthesized by parasites. Modification of proteins with GPIs is obligatory for parasite survival as GPI-anchored proteins (GPI-APs) play essential roles in all life cycle stages of the parasites, including development, egress, gametogenesis, motility, and host cell adhesion and invasion. Here, we discuss the current knowledge on the structures and potential functions of the glycan moieties of parasite proteins. The knowledge has important implications for the development of drugs and vaccines for malaria.
Topics: Animals; Glycosylation; Parasites; Plasmodium falciparum; Protein Processing, Post-Translational; Glycosylphosphatidylinositols; Polysaccharides; Protozoan Proteins
PubMed: 38262838
DOI: 10.1016/j.pt.2023.12.006 -
Environmental Microbiology Dec 2023Growing evidence suggests that microbiomes have been shaping the evolutionary pathways of macroorganisms for millennia and that these tiny symbionts can influence, and...
Growing evidence suggests that microbiomes have been shaping the evolutionary pathways of macroorganisms for millennia and that these tiny symbionts can influence, and possibly even control, species interactions like host-parasite relationships. Yet, while studies have investigated host-parasites and microbiomes separately, little has been done to understand all three groups synergistically. Here, we collected infected and uninfected Eurypanopeus depressus crab hosts from a coastal North Carolina oyster reef three times over 4 months. Infected crabs demonstrated an external stage of the rhizocephalan parasite, Loxothylacus panopaei. Community analyses revealed that microbial richness and diversity were significantly different among tissue types (uninfected crab, infected crab, parasite externae and parasite larvae) and over time (summer and fall). Specifically, the microbial communities from parasite externae and larvae had similar microbiomes that were consistent through time. Infected crabs demonstrated microbial communities spanning those of their host and parasite, while uninfected crabs showed more distinctive communities with greater variability over time. Microbial communities were also found to be indicators of early-stage infections. Resolving the microbial community composition of a host and its parasite is an important step in understanding the microbiome's role in the host-parasite relationship and determining how this tripartite relationship impacts coevolutionary processes.
Topics: Animals; Parasites; Host-Parasite Interactions; Brachyura; Parasitic Diseases; Microbiota
PubMed: 37918974
DOI: 10.1111/1462-2920.16533 -
Molecular Microbiology Mar 2024An essential step in the life cycle of malaria parasites is their egress from hepatocytes, which enables the transition from the asymptomatic liver stage to the... (Review)
Review
An essential step in the life cycle of malaria parasites is their egress from hepatocytes, which enables the transition from the asymptomatic liver stage to the pathogenic blood stage of infection. To exit the liver, Plasmodium parasites first disrupt the parasitophorous vacuole membrane that surrounds them during their intracellular replication. Subsequently, parasite-filled structures called merosomes emerge from the infected cell. Shrouded by host plasma membrane, like in a Trojan horse, parasites enter the vasculature undetected by the host immune system and travel to the lung where merosomes rupture, parasites are released, and the blood infection stage begins. This complex, multi-step process must be carefully orchestrated by the parasite and requires extensive manipulation of the infected host cell. This review aims to outline the known signaling pathways that trigger exit, highlight Plasmodium proteins that contribute to the release of liver-stage merozoites, and summarize the accompanying changes to the hepatic host cell.
Topics: Animals; Humans; Parasites; Liver; Hepatocytes; Plasmodium; Malaria; Erythrocytes; Protozoan Proteins
PubMed: 37602900
DOI: 10.1111/mmi.15141 -
Acta Parasitologica Mar 2024As a result of environmental imbalances of anthropogenic origin, the potential for transmission of parasites and viruses between different primates, including humans,... (Review)
Review
PURPOSE
As a result of environmental imbalances of anthropogenic origin, the potential for transmission of parasites and viruses between different primates, including humans, might increase. Thus, parasitic studies have great relevance to primatology, which motivated us to conduct a literature review to synthesize the information available in American primates of the Callithrix genus.
METHODS
We carried out the bibliographic search on the main groups of parasites (protozoa, helminths, arthropods, ectoparasites) and viruses found in Callithrix in Brazil in search platforms and consider all manuscript that appeared in search engines, published between the years 1910 and December 2022. In each selected article, the following information was recorded: the host species; parasite taxa; scientific classification of the parasite; host habitat (free-living, captive); diagnostic technique; state; and bibliographic reference. Data were tabulated and arranged in a parasite-host table.
RESULTS
Some endemic genera, such as Callithrix, are widely distributed geographically across Brazil and have characteristics of adaptation to different habitats due to their flexibility in diet and behavior. These factors can make them subject to a greater diversity of parasites and viruses in the country. Here, we identified 68 parasitic taxa, belonging to the clades protozoa (n = 22), helminths (n = 34), ectoparasites (n = 7), and viruses (n = 5). Out of this total, 19 have zoonotic potential. Of the six existing marmoset species, Callithrix jacchus was the most frequent in studies, and Callithrix flaviceps did not have reports. All regions of the country had occurrences, mainly the Southeast, where 54% of the cases were reported. In 46% of the reported parasites and viruses, it was not possible to identify the corresponding species.
CONCLUSION
We conclude that in part of the works the identification methods are not being specific, which makes it difficult to identify the species that affects Callithrix spp. Furthermore, the studies present geographic disparities, being concentrated in the southeast of the country, making it impossible to have a more uniform analysis of the findings. Thus, it is observed that information about parasites and viruses is incipient in the genus Callithrix in Brazil.
Topics: Animals; Brazil; Callithrix; Parasites; Monkey Diseases; Viruses; Virus Diseases; Parasitic Diseases, Animal
PubMed: 38184509
DOI: 10.1007/s11686-023-00766-y -
Trends in Parasitology Mar 2024Nematodes, a diverse group of roundworms, exhibit a wide range of dietary habits, including parasitism of animals and plants. These parasites cause substantial economic... (Review)
Review
Nematodes, a diverse group of roundworms, exhibit a wide range of dietary habits, including parasitism of animals and plants. These parasites cause substantial economic losses in agriculture and pose significant health challenges to humans and animals. This review explores the unique adaptations of parasitic nematodes, emphasizing their nutritional requirements and metabolic dependencies. Recent research has identified cross-kingdom compartmentalization of vitamin B5 biosynthesis in some parasitic nematodes, shedding light on coevolutionary dynamics and potential targets for control strategies. Several open questions remain regarding the complexity of nematode nutrition, host manipulation, evolutionary adaptations, and the influence of environmental factors on their metabolic processes. Understanding these aspects offers promising avenues for targeted interventions to manage and control these economically and medically important parasites.
Topics: Animals; Humans; Nematoda; Plants; Parasites; Agriculture; Feeding Behavior
PubMed: 38262837
DOI: 10.1016/j.pt.2023.12.013 -
Ecology Feb 2024Host heterogeneity can affect parasite transmission, but determining underlying traits and incorporating them into transmission models remains challenging. Body size is...
Host heterogeneity can affect parasite transmission, but determining underlying traits and incorporating them into transmission models remains challenging. Body size is easily measured and affects numerous ecological interactions, including transmission. In the snail-schistosome system, larger snails have a higher exposure to parasites but lower susceptibility to infection per parasite. We quantified the effect of size-based heterogeneity on population-level transmission by conducting transmission trials in differently size-structured snail populations and competing size-dependent transmission models. Populations with greater proportions of large snails had lower prevalence, and small snails were shielded from infection by co-occurring large conspecifics. Furthermore, a fully dependent transmission model that incorporated body size in both exposure and susceptibility outperformed other candidate models considered. Incorporating traits such as body size, which are affected by and directly affect host ecology, into transmission models could yield insights into natural dynamics and disease mitigation in many systems.
Topics: Animals; Parasites; Schistosoma; Snails; Host-Parasite Interactions
PubMed: 38032549
DOI: 10.1002/ecy.4221 -
The Kelch13 compartment contains highly divergent vesicle trafficking proteins in malaria parasites.PLoS Pathogens Dec 2023Single amino acid changes in the parasite protein Kelch13 (K13) result in reduced susceptibility of P. falciparum parasites to artemisinin and its derivatives (ART)....
Single amino acid changes in the parasite protein Kelch13 (K13) result in reduced susceptibility of P. falciparum parasites to artemisinin and its derivatives (ART). Recent work indicated that K13 and other proteins co-localising with K13 (K13 compartment proteins) are involved in the endocytic uptake of host cell cytosol (HCCU) and that a reduction in HCCU results in reduced susceptibility to ART. HCCU is critical for parasite survival but is poorly understood, with the K13 compartment proteins among the few proteins so far functionally linked to this process. Here we further defined the composition of the K13 compartment by analysing more hits from a previous BioID, showing that MyoF and MCA2 as well as Kelch13 interaction candidate (KIC) 11 and 12 are found at this site. Functional analyses, tests for ART susceptibility as well as comparisons of structural similarities using AlphaFold2 predictions of these and previously identified proteins showed that vesicle trafficking and endocytosis domains were frequent in proteins involved in resistance or endocytosis (or both), comprising one group of K13 compartment proteins. While this strengthened the link of the K13 compartment to endocytosis, many proteins of this group showed unusual domain combinations and large parasite-specific regions, indicating a high level of taxon-specific adaptation of this process. Another group of K13 compartment proteins did not influence endocytosis or ART susceptibility and lacked detectable vesicle trafficking domains. We here identified the first protein of this group that is important for asexual blood stage development and showed that it likely is involved in invasion. Overall, this work identified novel proteins functioning in endocytosis and at the K13 compartment. Together with comparisons of structural predictions it provides a repertoire of functional domains at the K13 compartment that indicate a high level of adaption of endocytosis in malaria parasites.
Topics: Animals; Antimalarials; Plasmodium falciparum; Parasites; Protozoan Proteins; Drug Resistance; Malaria, Falciparum; Mutation
PubMed: 38039338
DOI: 10.1371/journal.ppat.1011814 -
Cells Oct 2023Tuft cells have recently emerged as the focus of intense interest following the discovery of their chemosensory role in the intestinal tract, and their ability to... (Review)
Review
Tuft cells have recently emerged as the focus of intense interest following the discovery of their chemosensory role in the intestinal tract, and their ability to activate Type 2 immune responses to helminth parasites. Moreover, they populate a wide range of mucosal tissues and are intimately connected to immune and neuronal cells, either directly or through the release of pharmacologically active mediators. They are now recognised to fulfil both homeostatic roles, in metabolism and tissue integrity, as well as acting as the first sensors of parasite infection, immunity to which is lost in their absence. In this review we focus primarily on the importance of tuft cells in the intestinal niche, but also link to their more generalised physiological role and discuss their potential as targets for the treatment of gastrointestinal disorders.
Topics: Animals; Intestinal Mucosa; Helminths; Parasitic Diseases; Parasites; Immunity
PubMed: 37887321
DOI: 10.3390/cells12202477 -
Current Opinion in Microbiology Dec 2023Apicomplexan parasites are a large and diverse clade of protists responsible for significant diseases of humans and animals. Central to the ability of these parasites to... (Review)
Review
Apicomplexan parasites are a large and diverse clade of protists responsible for significant diseases of humans and animals. Central to the ability of these parasites to colonize their host and evade immune responses is an expanded repertoire of gene-expression programs that requires the coordinated action of complex transcriptional networks. DNA-binding proteins and chromatin regulators are essential orchestrators of apicomplexan gene expression that often act in concert. Although apicomplexan genomes encode various families of putative DNA-binding proteins, most remain functionally and mechanistically unexplored. This review highlights the versatile role of myeloblastosis (Myb) domain-containing proteins in apicomplexan parasites as transcription factors and chromatin regulators. We explore the diversity of Myb domain structure and use phylogenetic analysis to identify common features across the phylum. This provides a framework to discuss functional heterogeneity and regulation of Myb domain-containing proteins particularly emphasizing their role in parasite differentiation.
Topics: Animals; Humans; Parasites; Phylogeny; Transcription Factors; DNA-Binding Proteins; Chromatin
PubMed: 37866202
DOI: 10.1016/j.mib.2023.102395 -
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