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Cellular Microbiology May 2019Intravital fluorescence microscopy (IVM) is a powerful technique for imaging multiple organs, including the brain of living mice and rats. It enables the direct... (Review)
Review
Intravital fluorescence microscopy (IVM) is a powerful technique for imaging multiple organs, including the brain of living mice and rats. It enables the direct visualisation of cells in situ providing a real-life view of biological processes that in vitro systems cannot. In addition, to the technological advances in microscopy over the last decade, there have been supporting innovations in data storage and analytical packages that enable the visualisation and analysis of large data sets. Here, we review the advantages and limitations of techniques predominantly used for brain IVM, including thinned skull windows, open skull cortical windows, and a miniaturised optical system based on microendoscopic probes that can be inserted into deep tissues. Further, we explore the relevance of these techniques for the field of parasitology. Several protozoan infections are associated with neurological symptoms including Plasmodium spp., Toxoplasma spp., and Trypanosoma spp. IVM has led to crucial findings on these parasite species, which are discussed in detail in this review.
Topics: Animals; Brain; Host-Parasite Interactions; Intravital Microscopy; Mice; Microscopy, Fluorescence; Plasmodium; Protozoan Infections; Rats; Toxoplasma; Trypanosoma
PubMed: 30830993
DOI: 10.1111/cmi.13024 -
Biotechnology Advances 2016Lectins are proteins/glycoproteins of non-immune origin that agglutinate red blood cells, lymphocytes, fibroblasts, etc., and bind reversibly to carbohydrates present on... (Review)
Review
Lectins are proteins/glycoproteins of non-immune origin that agglutinate red blood cells, lymphocytes, fibroblasts, etc., and bind reversibly to carbohydrates present on the apposing cells. They have at least two carbohydrate binding sites and their binding can be inhibited by one or more carbohydrates. Owing to carbohydrate binding specificity of lectins, they mediate cell-cell interactions and play role in protozoan adhesion and host cell cytotoxicity, thus are central to the pathogenic property of the parasite. Several parasitic protozoa possess lectins which mediate parasite adherence to host cells based on their carbohydrate specificities. These interactions could be exploited for development of novel therapeutics, targeting the adherence and thus helpful in eradicating wide spread of protozoan diseases. The current review highlights the present state knowledge with regard to protozoal lectins with an emphasis on their haemagglutination activity, carbohydrate specificity, characteristics and also their role in pathogenesis notably as adhesion molecules, thereby aiding the pathogen in disease establishment.
Topics: Animals; Carbohydrates; Hemagglutination; Host-Pathogen Interactions; Humans; Lectins; Mice; Protozoan Infections; Protozoan Proteins
PubMed: 27268207
DOI: 10.1016/j.biotechadv.2016.06.002 -
Molecular Immunology Sep 2015The lectin pathway of the complement system has a pivotal role in the defense against infectious organisms. After binding of mannan-binding lectin (MBL), ficolins or... (Review)
Review
The lectin pathway of the complement system has a pivotal role in the defense against infectious organisms. After binding of mannan-binding lectin (MBL), ficolins or collectin 11 to carbohydrates or acetylated residues on pathogen surfaces, dimers of MBL-associated serine proteases 1 and 2 (MASP-1 and MASP-2) activate a proteolytic cascade, which culminates in the formation of the membrane attack complex and pathogen lysis. Alternative splicing of the pre-mRNA encoding MASP-1 results in two other products, MASP-3 and MAp44, which regulate activation of the cascade. A similar mechanism allows the gene encoding MASP-2 to produce the truncated MAp19 protein. Polymorphisms in MASP1 and MASP2 genes are associated with protein serum levels and functional activity. Since the first report of a MASP deficiency in 2003, deficiencies in lectin pathway proteins have been associated with recurrent infections and several polymorphisms were associated with the susceptibility or protection to infectious diseases. In this review, we summarize the findings on the role of MASP polymorphisms and serum levels in bacterial, viral and protozoan infectious diseases.
Topics: Bacterial Infections; Complement Pathway, Mannose-Binding Lectin; Complement System Proteins; Gene Expression Regulation; Humans; Mannose-Binding Lectin; Mannose-Binding Protein-Associated Serine Proteases; Polymorphism, Genetic; Protozoan Infections; Signal Transduction; Virus Diseases
PubMed: 25862418
DOI: 10.1016/j.molimm.2015.03.245 -
Archives of Medical Research Nov 2017The human gut is a highly complex ecosystem with an extensive microbial community, and the influence of the intestinal microbiota reaches the entire host organism. For... (Review)
Review
The human gut is a highly complex ecosystem with an extensive microbial community, and the influence of the intestinal microbiota reaches the entire host organism. For example, the microbiome regulates fat storage, stimulates or renews epithelial cells, and influences the development and maturation of the brain and the immune system. Intestinal microbes can protect against infection by pathogenic bacteria, viruses, fungi and parasites. Hence, the maintenance of homeostasis between the gut microbiota and the rest of the body is crucial for health, with dysbiosis affecting disease. This review focuses on intestinal protozoa, especially those still representing a public health problem in Mexico, and their interactions with the microbiome and the host. The decrease in prevalence of intestinal helminthes in humans left a vacant ecological niche that was quickly occupied by protozoa. Although the mechanisms governing the interaction between intestinal microbiota and protozoa are poorly understood, it is known that the composition of the intestinal bacterial populations modulates the progression of protozoan infection and the outcome of parasitic disease. Most reports on the complex interactions between intestinal bacteria, protozoa and the immune system emphasize the protective role of the microbiota against protozoan infection. Insights into such protection may facilitate the manipulation of microbiota components to prevent and treat intestinal protozoan infections. Here we discuss recent findings about the immunoregulatory effect of intestinal microbiota with regards to intestinal colonization by protozoa, focusing on infections by Entamoeba histolytica, Blastocystis spp, Giardia duodenalis, Toxoplasma gondii and Cryptosporidium parvum. The possible consequences of the microbiota on parasitic, allergic and autoimmune disorders are also considered.
Topics: Animals; Dysbiosis; Gastrointestinal Microbiome; Homeostasis; Humans; Mexico; Parasites; Protozoan Infections
PubMed: 29290328
DOI: 10.1016/j.arcmed.2017.11.015 -
Trends in Parasitology Jun 2022γ-aminobutyric acid (GABA) is a nonstructural amino acid that serves diverse functions in unicellular and multicellular organisms. Besides its widely established role... (Review)
Review
γ-aminobutyric acid (GABA) is a nonstructural amino acid that serves diverse functions in unicellular and multicellular organisms. Besides its widely established role in mammals as an inhibitory neurotransmitter, the diverse biological roles and metabolism of GABA in protozoan parasites have begun to be unveiled. GABA acts as either the intracellular signal or cell-to-cell messenger to mediate a variety of cellular responses that protect the parasites from environmental and host-derived stress. Moreover, GABA metabolism was found to be tightly regulated, involving protein machinery confined to the protozoa lineage. Meanwhile, host-parasite GABAergic interaction plays a role in the pathogenesis and disease manifestation of protozoan infections. Therefore, the GABAergic system apparently is broadly involved in essential biological and pathophysiological processes and is well conserved in parasitic and free-living protozoa.
Topics: Animals; Host-Parasite Interactions; Mammals; Parasites; Protozoan Infections; gamma-Aminobutyric Acid
PubMed: 35264298
DOI: 10.1016/j.pt.2022.02.004 -
Molecular and Biochemical Parasitology Oct 2014The diplomonad genera are here represented by three highly diverse species, both free-living (Hexamita inflata), and parasitic (Spironucleus vortens and Giardia... (Review)
Review
The diplomonad genera are here represented by three highly diverse species, both free-living (Hexamita inflata), and parasitic (Spironucleus vortens and Giardia intestinalis). All three are moderately aerotolerant flagellates, inhabiting environments where O2 tensions are low and fluctuating. Many diplomonads are opportunistic pathogens of avian, terrestrial and aquatic animals. Hexamitids inhabit deep waters and sediments of lakes and marine basins, S. vortens commonly infects the intestinal tract of ornamental fish, particularly of cichlids and cyprinids, and G. intestinalis, the upper intestinal tracts of humans as well as domestic and farm animals. Despite these very different habitats, their known physiological and biochemical characteristics are similar, but they do differ in significant respects as their lifestyles and life cycles demand. They have efficient O2 scavenging systems, and are highly effective at countering rapid O2 fluctuations, or clustering away from its source (except for G. intestinalis when attached to the jejunal villi). Their core metabolic pathways (glycolysis using pyrophosphate), incomplete tricarboxylic acid cycle (lacking α-ketoglutarate dehydrogenase), and amino acid metabolism (with an alternative energy-generating arginine dihydrolase pathway as a possibility in some cases), largely conform to those of other protists inhabiting low-O2 environments. Mitochondrial evolutionary reduction to give hydrogenosomes as seen in Spironucleus spp. has proceeded further to its minimal state in the mitosomes of G. intestinalis. Understanding of essential redox reactions and the maintentence of redox state, especially in the infective encysted stage of G. intestinalis provide increasing possibilities for parasite control. To this aim a plethora of new synthetic chemicals and natural products (especially those from garlic, Allium sativum) show promise as replacements for the highly effective (but potentially toxic to higher organisms) 5-nitroimidazoles (e.g., metronidazole) in the treatment and/or prevention of dimplomonad infection in humans and animals.
Topics: Antiprotozoal Agents; Cytoplasmic Vesicles; Cytoskeleton; Diplomonadida; Genomics; Giardia; Life Cycle Stages; Organelles; Phylogeny; Protozoan Infections
PubMed: 25448769
DOI: 10.1016/j.molbiopara.2014.10.002 -
Revista Brasileira de Parasitologia... 2019Tritrichomonas foetus is a parasite that has been definitively identified as an agent of trichomonosis, a disease characterized by chronic diarrhea. T. foetus colonizes... (Review)
Review
Tritrichomonas foetus is a parasite that has been definitively identified as an agent of trichomonosis, a disease characterized by chronic diarrhea. T. foetus colonizes portions of the feline large intestine, and manifests as chronic and recurrent diarrhea with mucus and fresh blood, which is often unresponsive to common drugs. Diagnosis of a trichomonad infection is made by either the demonstration of the trophozoite on a direct fecal smear, fecal culture and subsequent microscopic examination of the parasite, or extraction of DNA in feces and amplification by the use of molecular tools. T. foetus is commonly misidentified as other flagellate protozoa such as Giardia duodenalis and Pentatrichomonas hominis. Without proper treatment, the diarrhea may resolve spontaneously in months to years, but cats can remain carriers of the parasite. This paper intends to serve as a source of information for investigators and veterinarians, reviewing the most important aspects of feline trichomonosis, such as trichomonad history, biology, clinical manifestations, pathogenesis, world distribution, risk factors, diagnosis, and treatment.
Topics: Animals; Cat Diseases; Cats; DNA, Protozoan; Diarrhea; Feces; Polymerase Chain Reaction; Protozoan Infections, Animal; Risk Factors; Tritrichomonas foetus
PubMed: 30892464
DOI: 10.1590/S1984-29612019005 -
International Journal of Molecular... Nov 2019Protozoan diseases continue to be a worldwide social and economic health problem. Increased drug resistance, emerging cross resistance, and lack of new drugs with novel... (Review)
Review
Protozoan diseases continue to be a worldwide social and economic health problem. Increased drug resistance, emerging cross resistance, and lack of new drugs with novel mechanisms of action significantly reduce the effectiveness of current antiprotozoal therapies. While drug resistance associated to anti-infective agents is a reality, society seems to remain unaware of its proportions and consequences. Parasites usually develops ingenious and innovative mechanisms to achieve drug resistance, which requires more research and investment to fight it. In this review, drug resistance developed by protozoan parasites , and will be discussed.
Topics: Animals; Antiprotozoal Agents; Humans; Leishmania; Malaria; Plasmodium; Protozoan Infections
PubMed: 31731801
DOI: 10.3390/ijms20225748 -
Frontiers in Immunology 2021Protozoan parasite infection causes severe diseases in humans and animals, leading to tremendous economic and medical pressure. Natural immunity is the first line of... (Review)
Review
Protozoan parasite infection causes severe diseases in humans and animals, leading to tremendous economic and medical pressure. Natural immunity is the first line of defence against parasitic infection. Currently, the role of natural host immunity in combatting parasitic infection is unclear, so further research on natural host immunity against parasites will provide a theoretical basis for the prevention and treatment of related parasitic diseases. Extracellular traps (ETs) are an important natural mechanism of immunity involving resistance to pathogens. When immune cells such as neutrophils and macrophages are stimulated by external pathogens, they release a fibrous network structure, consisting mainly of DNA and protein, that can capture and kill a variety of extracellular pathogenic microorganisms. In this review, we discuss the relevant recently reported data on ET formation induced by protozoan parasite infection, including the molecular mechanisms involved, and discuss the role of ETs in the occurrence and development of parasitic diseases.
Topics: Animals; Extracellular Traps; Host-Parasite Interactions; Humans; Immunity, Innate; Leishmania; Neutrophils; Plasmodium; Protozoan Infections; Protozoan Infections, Animal; Signal Transduction; Toxoplasma
PubMed: 34970259
DOI: 10.3389/fimmu.2021.770246 -
The Veterinary Clinics of North... Mar 2020Internal parasites are a major concern in livestock production because they can impact the health and well-being of animals clinically and subclinically, and ultimately... (Review)
Review
Internal parasites are a major concern in livestock production because they can impact the health and well-being of animals clinically and subclinically, and ultimately cause significant production loss. Among these internal parasites are nematodes, tapeworms, flukes, and coccidian protozoans. This review focuses on the diagnostic tests that are routinely performed by veterinarians and diagnostic laboratories, but also highlights recently developed tools that may improve diagnostic capabilities, including molecular and immunodiagnostic tests. Overall, diagnostic tests for parasites of livestock are an integral part of health management practices, and for assessing individual animal and herd health.
Topics: Animals; Diagnostic Techniques and Procedures; Feces; Livestock; Protozoan Infections, Animal
PubMed: 32029179
DOI: 10.1016/j.cvfa.2019.12.003