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Frontiers in Immunology 2022The physical barrier of the intestine and associated mucosal immunity maintains a delicate homeostatic balance between the host and the external environment by... (Review)
Review
The physical barrier of the intestine and associated mucosal immunity maintains a delicate homeostatic balance between the host and the external environment by regulating immune responses to commensals, as well as functioning as the first line of defense against pathogenic microorganisms. Understanding the orchestration and characteristics of the intestinal mucosal immune response during commensal or pathological conditions may provide novel insights into the mechanisms underlying microbe-induced immunological tolerance, protection, and/or pathogenesis. Over the last decade, our knowledge about the interface between the host intestinal mucosa and the gut microbiome has been dominated by studies focused on bacterial communities, helminth parasites, and intestinal viruses. In contrast, specifically how commensal and pathogenic protozoa regulate intestinal immunity is less well studied. In this review, we provide an overview of mucosal immune responses induced by intestinal protozoa, with a major focus on the role of different cell types and immune mediators triggered by commensal ( spp. and spp.) and pathogenic (, , ) protozoa. We will discuss how these various protozoa modulate innate and adaptive immune responses induced in experimental models of infection that benefit or harm the host.
Topics: Cryptosporidiosis; Cryptosporidium; Humans; Immunity, Mucosal; Intestinal Mucosa; Intestines
PubMed: 36211380
DOI: 10.3389/fimmu.2022.963723 -
Parasites & Vectors Jan 2021Toxoplasma gondii is a protozoan parasite with a complex life cycle and a cosmopolitan host range. The asexual part of its life cycle can be perpetually sustained in a... (Review)
Review
Toxoplasma gondii is a protozoan parasite with a complex life cycle and a cosmopolitan host range. The asexual part of its life cycle can be perpetually sustained in a variety of intermediate hosts through a combination of carnivory and vertical transmission. However, T. gondii produces gametes only in felids after the predation of infected intermediate hosts. The parasite changes the behavior of its intermediate hosts by reducing their innate fear to cat odors and thereby plausibly increasing the probability that the definitive host will devour the infected host. Here, we provide a short description of such parasitic behavioral manipulation in laboratory rodents infected with T. gondii, along with a bird's eye view of underpinning biological changes in the host. We also summarize critical gaps and opportunities for future research in this exciting research area with broad implications in the transdisciplinary study of host-parasite relationships.
Topics: Animals; Behavior, Animal; Cats; Fear; Host-Parasite Interactions; Humans; Life Cycle Stages; Odorants; Rodentia; Toxoplasma; Toxoplasmosis, Animal
PubMed: 33494777
DOI: 10.1186/s13071-020-04528-x -
Clinical Microbiology and Infection :... Dec 2019Parasitic infections are responsible for a significant burden of disease worldwide as a result of international travel and immigration. More accurate diagnostic tools... (Review)
Review
BACKGROUND
Parasitic infections are responsible for a significant burden of disease worldwide as a result of international travel and immigration. More accurate diagnostic tools are necessary in support to parasite control and elimination programmes in endemic regions as well as for rapid case detection in non-endemic areas. Digital PCR (dPCR) is a powerful technology with recent applications in parasitology.
AIMS
This review provides for the first time an overview of dPCR as a novel technology applied to detection of parasitic infections, and highlights the most relevant potential benefits of this assay.
SOURCES
Peer-reviewed literature pertinent to this review based on PubMed, Cochrane and Embase databases as well as laboratory experience of authors.
CONTENT
Among the 86 studies retrieved, 17 used the dPCR applied to parasites belonging to protozoa (8), helminths (8) and arthropods (1) of clinical human interest. dPCR was adopted in four studies, respectively, for Plasmodium and Schistosoma japonicum. dPCR led to clear advantages over quantitative real-time PCR in P. falciparum and spp., and in S. japonicum showing higher sensitivity; and in Cryptosporidium with higher stability to inhibitors from stool. For all parasites, dPCR allows absolute quantitation without the need of a standard curve. Various dPCR platforms were used. A few critical factors need consideration: DNA load, choice of platform and reaction optimization.
IMPLICATIONS
Owing to its sensitivity and quantitative characteristics, dPCR is a potential candidate to become an appealing new method among the molecular technologies for parasite detection and quantitative analysis in the future. In general, it has more applications than genomic DNA detection only, such as quantitation in mixed infections, gene expression and mutation analysis. dPCR should be considered in malaria screening and diagnosis as a complement to routine assays and in schistosomiasis elimination programmes. Standardized strategies and further studies are needed for the integration of dPCR in routine clinical laboratory.
Topics: Animals; Diagnostic Tests, Routine; Humans; Mass Screening; Microfluidic Analytical Techniques; Molecular Diagnostic Techniques; Parasites; Parasitic Diseases; Parasitology; Polymerase Chain Reaction
PubMed: 31226445
DOI: 10.1016/j.cmi.2019.06.009 -
Journal of Clinical Medicine Feb 2021Nowadays, there is a considerable interest to study the biological and microbiological changes that accompany orthodontic treatment. Growing knowledge on oral microbiota... (Review)
Review
Nowadays, there is a considerable interest to study the biological and microbiological changes that accompany orthodontic treatment. Growing knowledge on oral microbiota allows, day after day, to identify and characterize the microbial arrangements specifically associated with oral and extra-oral conditions. The aim of the present work is to highlight any further correlations between orthodontic appliances and the qualitative and quantitative modifications of the oral microbiota, such as predisposing factors for the onset of caries, periodontal diseases, and other infections, which can impact the oral and systemic health of the orthodontic patients. When compared with subjects without orthodontic appliances, orthodontic patients reported significant qualitative and quantitative differences in supra- and subgingival plaque during the entire treatment period. Certain components of fixed appliances (mainly bonded molar brackets, ceramic brackets, and elastomeric ligatures) showed high risks of periodontal disease and tooth decay for patients. An unclear prevalence of spp. and the paucity of studies on viruses and protozoas in the oral microbiota of orthodontic patients need to be further investigated. The evidence emerging from this study could guide clinicians in modulating the timing of controls and enhance patient motivation to prevent the formation of mature plaque, thus reducing the risks of oral-plaque-related diseases.
PubMed: 33669186
DOI: 10.3390/jcm10040780 -
Parasitology Apr 2022Arginine methylation is a post-translational modification involved in gene transcription, signalling pathways, DNA repair, RNA metabolism and splicing, among others,... (Review)
Review
Arginine methylation is a post-translational modification involved in gene transcription, signalling pathways, DNA repair, RNA metabolism and splicing, among others, mechanisms that in protozoa parasites may be involved in pathogenicity-related events. This modification is performed by protein arginine methyltransferases (PRMTs), which according to their products are divided into three main types: type I yields monomethylarginine (MMA) and asymmetric dimethylarginine; type II produces MMA and symmetric dimethylarginine; whereas type III catalyses MMA only. Nine PRMTs (PRMT1 to PRMT9) have been characterized in humans, whereas in protozoa parasites, except for Giardia intestinalis, three to eight PRMTs have been identified, where in each group there are at least two enzymes belonging to type I, the majority with higher similarity to human PRMT1, and one of type II, related to human PRMT5. However, the information on the role of most of these enzymes in the parasites biology is limited so far. Here, current knowledge of PRMTs in protozoan parasites is reviewed; these enzymes participate in the cell growth, stress response, stage transitions and virulence of these microorganisms. Thus, PRMTs are attractive targets for developing new therapeutic strategies against these pathogens.
Topics: Animals; Humans; Methylation; Parasites; Protein Processing, Post-Translational; Protein-Arginine N-Methyltransferases; Repressor Proteins
PubMed: 35331350
DOI: 10.1017/S0031182021002043 -
Paediatric Respiratory Reviews Sep 2022
Topics: Animals; Humans; Zoonoses; Lung
PubMed: 36075818
DOI: 10.1016/j.prrv.2022.07.002 -
Therapeutic Advances in Gastroenterology 2022The human gut microbiome (GM) is a complex ecosystem that includes numerous prokaryotic and eukaryotic inhabitants. The composition of GM can influence an array of host... (Review)
Review
The human gut microbiome (GM) is a complex ecosystem that includes numerous prokaryotic and eukaryotic inhabitants. The composition of GM can influence an array of host physiological functions including immune development. Accumulating evidence suggest that several members of non-bacterial microbiota, including protozoa and helminths, that were earlier considered as pathogens, could have a commensal or beneficial relationship with the host. Here we examine the most recent data from omics studies on prokaryota-meiofauna-host interaction as well as the impact of gut parasitome on gut bacterial ecology and its role as 'immunological driver' in health and disease to glimpse new therapeutic perspectives.
PubMed: 35509426
DOI: 10.1177/17562848221091524 -
Current Opinion in Microbiology Dec 2019Many microbial eukaryotes exhibit cell-cell communication to co-ordinate group behaviours as a strategy to exploit a changed environment, adapt to adverse conditions or... (Review)
Review
Many microbial eukaryotes exhibit cell-cell communication to co-ordinate group behaviours as a strategy to exploit a changed environment, adapt to adverse conditions or regulate developmental responses. Although best characterised in bacteria, eukaryotic microbes have also been revealed to cooperate to optimise their survival or dissemination. An excellent model for these processes are African trypanosomes, protozoa responsible for important human and animal disease in sub Saharan Africa. These unicellular parasites use density sensing in their mammalian host to prepare for transmission. Recently, the signal and signal transduction pathway underlying this activity have been elucidated, revealing that the parasite exploits oligopeptide signals generated by released peptidases to monitor cell density and so generate transmission stages. Here we review the evidence for this elegant quorum sensing mechanism and its parallels with similar mechanisms in other microbial systems. We also discuss its implications for disease spread in the context of coinfections involving different trypanosome species.
Topics: Africa South of the Sahara; Animals; Coinfection; Humans; Quorum Sensing; Signal Transduction; Trypanosoma brucei brucei; Trypanosomiasis, African
PubMed: 31442903
DOI: 10.1016/j.mib.2019.07.001 -
Frontiers in Molecular Biosciences 2024
PubMed: 38800093
DOI: 10.3389/fmolb.2024.1422955 -
Trends in Parasitology Dec 2020Parasitic protozoa of the phylum Apicomplexa cause a range of human and animal diseases. Their complex life cycles - often heteroxenous with sexual and asexual phases in... (Review)
Review
Parasitic protozoa of the phylum Apicomplexa cause a range of human and animal diseases. Their complex life cycles - often heteroxenous with sexual and asexual phases in different hosts - rely on elaborate cytoskeletal structures to enable morphogenesis and motility, organize cell division, and withstand diverse environmental forces. This review primarily focuses on studies using Toxoplasma gondii and Plasmodium spp. as the best studied apicomplexans; however, many cytoskeletal adaptations are broadly conserved and predate the emergence of the parasitic phylum. After decades cataloguing the constituents of such structures, a dynamic picture is emerging of the assembly and maintenance of apicomplexan cytoskeletons, illuminating how they template and orient critical processes during infection. These observations impact our view of eukaryotic diversity and offer future challenges for cell biology.
Topics: Adaptation, Physiological; Animals; Apicomplexa; Cytoskeleton; Humans; Life Cycle Stages; Plasmodium; Toxoplasma
PubMed: 33011071
DOI: 10.1016/j.pt.2020.09.001