Artigos de revistas: "Protozoa, Pathogenic"

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Souza, Wanderley de. "Secretory organelles of pathogenic protozoa". Anais da Academia Brasileira de Ciências 78, n.º 2 (junho de 2006): 271–92. http://dx.doi.org/10.1590/s0001-37652006000200008.

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Secretory processes play an important role on the biology and life cycles of parasitic protozoa. This review focus on basic aspects, from a cell biology perspective, of the secretion of (a) micronemes, rhoptries and dense granules in members of the Apicomplexa group, where these organelles are involved in the process of protozoan penetration into the host cell, survival within the parasitophorous vacuole and subsequent egress from the host cell, (b) the Maurer's cleft in Plasmodium, a structure involved in the secretion of proteins synthesized by the intravacuolar parasite and transported through vesicles to the erythrocyte surface, (c) the secretion of macromolecules into the flagellar pocket of trypanosomatids, and (d) the secretion of proteins which make the cyst wall of Giardia and Entamoeba, with the formation of encystation vesicles.

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Clipsham, Robert. "Avian pathogenic flagellated enteric protozoa". Seminars in Avian and Exotic Pet Medicine 4, n.º 3 (julho de 1995): 112–25. http://dx.doi.org/10.1016/s1055-937x(05)80035-0.

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Ndiaye, Mouhamadou, Khadim Diongue, Mame Cheikh Seck, Mamadou Alpha Diallo, Ekoué Kouevidjin, Aida Sadikh Badiane e Daouda Ndiaye. "Retrospective Assessment of The Intestinal Protozoan Distribution in Patients Admitted to The Hospital Aristide Le Dantec in Dakar, Senegal, from 2011 to 2020". Parasitologia 3, n.º 1 (23 de dezembro de 2022): 1–12. http://dx.doi.org/10.3390/parasitologia3010001.

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Infectious parasites, especially the intestinal protozoan parasites, continue to be a major public health problem in Africa, where many of the same factors contribute to the transmission of these parasites. This study was conducted to investigate the parasites causing intestinal protozoal infections diagnosed in Aristide Le Dantec hospital (Senegal). Direct examination and the Ritchie technique were used. Among the 3407 stool samples studied, 645 demonstrated the presence of intestinal protozoa in single parasitism, biparasitism, or polyparasitism, representing a prevalence of 18.93%. Out of a total of 645 protozoa, 579 (16.99%) were identified in monoparasitism in the following order: Entamoeba coli (6.87%) and Blastocystis hominis (5.69%) for low pathogenic species, and Entamoeba histolytica/dispar (2.31%) and Giardia intestinalis (1.32%) for pathogenic species. The rates of biparasitism and polyparasitism were 1.88% and 0.06%, respectively. The highest rate of parasites was 24.83% between the ages of 0–15 years. A logistical regression model indicated that intestinal protozoan infections were not associated with age groups. There was an association between age groups and Giardia intestinalis and Blastocystis hominis (p < 0.05). These results demonstrated the frequency of intestinal protozoa in Senegal. There is a need to implement treatment, prevention, and control measures to limit the circulation of these protozoan infections.

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Huang, C. M., H. C. Chen e C. H. Zierdt. "Magainin analogs effective against pathogenic protozoa." Antimicrobial Agents and Chemotherapy 34, n.º 9 (1 de setembro de 1990): 1824–26. http://dx.doi.org/10.1128/aac.34.9.1824.

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de Souza, Wanderley. "Special organelles of some pathogenic protozoa". Parasitology Research 88, n.º 12 (1 de dezembro de 2002): 1013–25. http://dx.doi.org/10.1007/s00436-002-0696-2.

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Reyes-López, Magda, Gerardo Ramírez-Rico, Jesús Serrano-Luna e Mireya de la Garza. "Activity of Apo-Lactoferrin on Pathogenic Protozoa". Pharmaceutics 14, n.º 8 (15 de agosto de 2022): 1702. http://dx.doi.org/10.3390/pharmaceutics14081702.

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Parasites and other eventually pathogenic organisms require the ability to adapt to different environmental conditions inside the host to assure survival. Some host proteins have evolved as defense constituents, such as lactoferrin (Lf), which is part of the innate immune system. Lf in its iron-free form (apo-Lf) and its peptides obtained by cleavage with pepsin are microbicides. Parasites confront Lf in mucosae and blood. In this work, the activity of Lf against pathogenic and opportunistic parasites such as Cryptosporidium spp., Eimeria spp., Entamoeba histolytica, Giardia duodenalis, Leishmania spp., Trypanosoma spp., Plasmodium spp., Babesia spp., Toxoplasma gondii, Trichomonas spp., and the free-living but opportunistic pathogens Naegleria fowleri and Acanthamoeba castellani were reviewed. The major effects of Lf could be the inhibition produced by sequestering the iron needed for their survival and the production of oxygen-free radicals to more complicated mechanisms, such as the activation of macrophages to phagocytes with the posterior death of those parasites. Due to the great interest in Lf in the fight against pathogens, it is necessary to understand the exact mechanisms used by this protein to affect their virulence factors and to kill them.

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Hall, B. Fenton. "Introduction: Host cell interactions of pathogenic protozoa". Seminars in Cell Biology 4, n.º 5 (outubro de 1993): 295–96. http://dx.doi.org/10.1006/scel.1993.1035.

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Upcroft, Peter. "Multiple drug resistance in the pathogenic protozoa". Acta Tropica 56, n.º 2-3 (março de 1994): 195–212. http://dx.doi.org/10.1016/0001-706x(94)90063-9.

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Dudlová, Adriána, Pavol Jarčuška, Silvia Jurišová, Zuzana Vasilková, Vladimír Krčméry e Peter Juriš. "Prevalence of non-pathogenic types of gastrointestinal protozoa in population in Slovakia and their potential importance in the aspect of public health". Acta Parasitologica 63, n.º 4 (19 de dezembro de 2018): 819–25. http://dx.doi.org/10.1515/ap-2018-0100.

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Abstract The aim of the research was to determine the prevalence of non-pathogenic protozoa circulating in the human population of Slovakia. We particularly focused on the socially deprived areas with poor sanitation conditions, as they are one of the factors affecting the transmission of these infections. Within this study, 2760 people were coprologically screened for the presence of protozoan cysts. The analyzed group comprised 1173 men and 1587 women from different regions of Slovakia. The total prevalence (2.03%) of non-pathogenic protozoa species was determined. The prevalence of Entamoeba coli was 0.80%, the prevalence of Endolimax nana 0.58%, and the prevalence of Blastocystis hominis was 0.65%. The presence of non-pathogenic protozoa was more frequent in women than that in men, in all age groups. The highest incidence of Entamoeba coli was found in children aged one month – seven years (0.79%), the lowest in the age group of 19–88 years (0.66%). Endolimax nana was most frequent in 8–18 year-olds (0.95%), where the statistical significance was found (p<0.05). The prevalence of Blastocystis hominis by the age group ranged from 0.39 to 0.95%. We did not find any statistical significance (p>0.05) for Entamoeba coli, and similarly for Blastocystis hominis associated with the sex and age. Although the circulation of non-pathogenic protozoa in the human population is far from being limited to the developing countries, their occurrence is also frequent in the population of developed countries. Despite their controversial pathogenicity, they should not be neglected, particularly in the patients with gastrointestinal symptoms.

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Wiser, Mark F. "Unique Endomembrane Systems and Virulence in Pathogenic Protozoa". Life 11, n.º 8 (12 de agosto de 2021): 822. http://dx.doi.org/10.3390/life11080822.

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Virulence in pathogenic protozoa is often tied to secretory processes such as the expression of adhesins on parasite surfaces or the secretion of proteases to assisted in tissue invasion and other proteins to avoid the immune system. This review is a broad overview of the endomembrane systems of pathogenic protozoa with a focus on Giardia, Trichomonas, Entamoeba, kinetoplastids, and apicomplexans. The focus is on unique features of these protozoa and how these features relate to virulence. In general, the basic elements of the endocytic and exocytic pathways are present in all protozoa. Some of these elements, especially the endosomal compartments, have been repurposed by the various species and quite often the repurposing is associated with virulence. The Apicomplexa exhibit the most unique endomembrane systems. This includes unique secretory organelles that play a central role in interactions between parasite and host and are involved in the invasion of host cells. Furthermore, as intracellular parasites, the apicomplexans extensively modify their host cells through the secretion of proteins and other material into the host cell. This includes a unique targeting motif for proteins destined for the host cell. Most notable among the apicomplexans is the malaria parasite, which extensively modifies and exports numerous proteins into the host erythrocyte. These modifications of the host erythrocyte include the formation of unique membranes and structures in the host erythrocyte cytoplasm and on the erythrocyte membrane. The transport of parasite proteins to the host erythrocyte involves several unique mechanisms and components, as well as the generation of compartments within the erythrocyte that participate in extraparasite trafficking.

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Brown, M. "Unexplored reservoirs of pathogenic bacteria: protozoa and biofilms". Trends in Microbiology 7, n.º 1 (1 de janeiro de 1999): 46–50. http://dx.doi.org/10.1016/s0966-842x(98)01425-5.

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Crabb, Brendan S. "Recent insights into virulence determinants of pathogenic protozoa". Current Opinion in Microbiology 9, n.º 4 (agosto de 2006): 365–66. http://dx.doi.org/10.1016/j.mib.2006.06.020.

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BENCHIMOL, M., B. KACHAR e W. DESOUZA. "Quick-freeze, deep visualization of the pathogenic protozoa". Cell Biology International Reports 14 (setembro de 1990): 253. http://dx.doi.org/10.1016/0309-1651(90)91111-g.

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Laskowski-Arce, Michelle A., e Kim Orth. "Acanthamoeba castellanii Promotes the Survival of Vibrio parahaemolyticus". Applied and Environmental Microbiology 74, n.º 23 (10 de outubro de 2008): 7183–88. http://dx.doi.org/10.1128/aem.01332-08.

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ABSTRACT Vibrio parahaemolyticus is a food-borne pathogen that naturally inhabits both marine and estuarine environments. Free-living protozoa exist in similar aquatic environments and function to control bacterial numbers by grazing on free-living bacteria. Protozoa also play an important role in the survival and spread of some pathogenic species of bacteria. We investigated the interaction between the protozoan Acanthamoeba castellanii and the bacterium Vibrio parahaemolyticus. We found that Acanthamoeba castellanii does not prey on Vibrio parahaemolyticus but instead secretes a factor that promotes the survival of Vibrio parahaemolyticus in coculture. These studies suggest that protozoa may provide a survival advantage to an extracellular pathogen in the environment.

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Yang, Jin-Lei, Danyang Li e Xiao-Yong Zhan. "Concept about the Virulence Factor of Legionella". Microorganisms 11, n.º 1 (27 de dezembro de 2022): 74. http://dx.doi.org/10.3390/microorganisms11010074.

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Pathogenic species of Legionella can infect human alveolar macrophages through Legionella-containing aerosols to cause a disease called Legionellosis, which has two forms: a flu-like Pontiac fever and severe pneumonia named Legionnaires’ disease (LD). Legionella is an opportunistic pathogen that frequently presents in aquatic environments as a biofilm or protozoa parasite. Long-term interaction and extensive co-evolution with various genera of amoebae render Legionellae pathogenic to infect humans and also generate virulence differentiation and heterogeneity. Conventionally, the proteins involved in initiating replication processes and human macrophage infections have been regarded as virulence factors and linked to pathogenicity. However, because some of the virulence factors are associated with the infection of protozoa and macrophages, it would be more accurate to classify them as survival factors rather than virulence factors. Given that the molecular basis of virulence variations among non-pathogenic, pathogenic, and highly pathogenic Legionella has not yet been elaborated from the perspective of virulence factors, a comprehensive explanation of how Legionella infects its natural hosts, protozoans, and accidental hosts, humans is essential to show a novel concept regarding the virulence factor of Legionella. In this review, we overviewed the pathogenic development of Legionella from protozoa, the function of conventional virulence factors in the infections of protozoa and macrophages, the host’s innate immune system, and factors involved in regulating the host immune response, before discussing a probably new definition for the virulence factors of Legionella.

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Dumètre, Aurélien, Dominique Aubert, Pierre-Henri Puech, Jeanne Hohweyer, Nadine Azas e Isabelle Villena. "Interaction Forces Drive the Environmental Transmission of Pathogenic Protozoa". Applied and Environmental Microbiology 78, n.º 4 (9 de dezembro de 2011): 905–12. http://dx.doi.org/10.1128/aem.06488-11.

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ABSTRACTThe protozoan parasitesGiardia duodenalis,Cryptosporidiumspp., andToxoplasma gondiiare pathogens that are resistant to a number of environmental factors and pose significant risks to public health worldwide. Their environmental transmission is closely governed by the physicochemical properties of their cysts (Giardia) and oocysts (CryptosporidiumandToxoplasma), allowing their transport, retention, and survival for months in water, soil, vegetables, and mollusks, which are the main reservoirs for human infection. Importantly, the cyst/oocyst wall plays a key role in that regard by exhibiting a complex polymeric coverage that determines the charge and hydrophobic characteristics of parasites' surfaces. Interaction forces between parasites and other environmental particles may be, in a first approximation, evaluated following the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of colloidal stability. However, due to the molecular topography and nano- to microstructure of the cyst/oocyst surface, non-DVLO hydrophobic forces together with additional steric attractive and/or repulsive forces may play a pivotal role in controlling the parasite behavior when the organism is subjected to various external conditions. Here, we review several parameters that enhance or hinder the adhesion of parasites to other particles and surfaces and address the role of fast-emerging techniques for mapping the cyst/oocyst surface, e.g., by measuring its topology and the generated interaction forces at the nano- to microscale. We discuss why characterizing these interactions could be a crucial step for managing the environmental matrices at risk of microbial pollution.

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Prole, David L., e Neil V. Marrion. "Identification of Putative Potassium Channel Homologues in Pathogenic Protozoa". PLoS ONE 7, n.º 2 (21 de fevereiro de 2012): e32264. http://dx.doi.org/10.1371/journal.pone.0032264.

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SMITH, A. W. "Protozoa and pathogenic bacteria: lessons learned from Legionella pneumophila". Journal of Eukaryotic Microbiology 52, n.º 2 (março de 2005): 27S—28S. http://dx.doi.org/10.1111/j.1550-7408.2005.05202003_2_4.x.

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De Souza, Wanderley. "Structural organization of the cell surface of pathogenic protozoa". Micron 26, n.º 5 (janeiro de 1995): 405–30. http://dx.doi.org/10.1016/0968-4328(95)00010-0.

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Agbedanu, P., No author No author, M. Brewer, No author No author, T. Day, M. Kimber, K. Anderson, S. Rasmussen e M. Carlson. "Involvement of a putative intercellular signal-recognizing G protein-coupled receptor in the engulfment of Salmonella by the protozoan Tetrahymena". Open Veterinary Journal 5, n.º 2 (2013): 69. http://dx.doi.org/10.5455/ovj.2013.v3.i2.p69.

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In an effort to investigate the molecular basis of protozoa engulfment-mediated hypervirulence of Salmonella in cattle, we evaluated protozoan G protein-coupled receptors (GPCRs) as transducers of Salmonella engulfment by the model protozoan Tetrahymena. Our laboratory previously demonstrated that non-pathogenic protozoa (including Tetrahymena) engulf Salmonella and then exacerbate its virulence in cattle, but the mechanistic details of the phenomenon are not fully understood. GPCRs were investigated since these receptors facilitate phagocytosis of particulates by Tetrahymena, and a GPCR apparently modulates bacterial engulfment for the pathogenic protozoan Entamoeba histolytica. A database search identified three putative Tetrahymena GPCRs, based on sequence homologies and predicted transmembrane domains, that were the focus of this study. Salmonella engulfment by Tetrahymena was assessed in the presence of suramin, a non-specific GPCR inhibitor. Salmonella engulfment was also assessed in Tetrahymena in which expression of putative GPCRs was knocked-down using RNAi. A candidate GPCR was then expressed in a heterologous yeast expression system for further characterization. Our results revealed that Tetrahymena were less efficient at engulfing Salmonella in the presence of suramin. Engulfment was reduced concordantly with a reduction in the density of protozoa. RNAi-based studies revealed that knock-down of one the Tetrahymena GPCRs caused diminished engulfment of Salmonella. Tetrahymena lysates activated this receptor in the heterologous expression system. These data demonstrate that the Tetrahymena receptor is a putative GPCR that facilitates bacterial engulfment by Tetrahymena. Activation of the putative GPCR seemed to be related to protozoan cell density, suggesting that its cognate ligand is an intercellular signaling molecule.

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Shanan, Salah, Hadi Abd, Magdi Bayoumi, Amir Saeed e Gunnar Sandström. "Prevalence of Protozoa Species in Drinking and Environmental Water Sources in Sudan". BioMed Research International 2015 (2015): 1–5. http://dx.doi.org/10.1155/2015/345619.

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Protozoa are eukaryotic cells distributed worldwide in nature and are receiving increasing attention as reservoirs and potential vectors for the transmission of pathogenic bacteria. In the environment, on the other hand, many genera of the protozoa are human and animal pathogens. Only limited information is available on these organisms in developing countries and so far no information on their presence is available from Sudan. It is necessary to establish a molecular identification of species of the protozoa from drinking and environmental water. 600 water samples were collected from five states (Gadarif, Khartoum, Kordofan, Juba, and Wad Madani) in Sudan and analysed by polymerase chain reaction (PCR) and sequencing. 57 out of 600 water samples were PCR positive for protozoa. 38 out of the 57 positive samples were identified by sequencing to contain 66 protozoa species including 19 (28.8%) amoebae, 17 (25.7%) Apicomplexa, 25 (37.9%) ciliates, and 5 (7.6%) flagellates. This study utilized molecular methods identified species belonging to all phyla of protozoa and presented a fast and accurate molecular detection and identification of pathogenic as well as free-living protozoa in water uncovering hazards facing public health.

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Land, Kirkwood M., e Patricia J. Johnson. "Molecular basis of metronidazole resistance in pathogenic bacteria and protozoa". Drug Resistance Updates 2, n.º 5 (outubro de 1999): 289–94. http://dx.doi.org/10.1054/drup.1999.0104.

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Jackson, P., M. Pappas e B. Hansen. "Fluorogenic substrate detection of viable intracellular and extracellular pathogenic protozoa". Science 227, n.º 4685 (25 de janeiro de 1985): 435–38. http://dx.doi.org/10.1126/science.2578226.

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Dumetz, Franck, e Catherine Merrick. "Parasitic Protozoa: Unusual Roles for G-Quadruplexes in Early-Diverging Eukaryotes". Molecules 24, n.º 7 (5 de abril de 2019): 1339. http://dx.doi.org/10.3390/molecules24071339.

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Guanine-quadruplex (G4) motifs, at both the DNA and RNA levels, have assumed an important place in our understanding of the biology of eukaryotes, bacteria and viruses. However, it is generally little known that their very first description, as well as the foundational work on G4s, was performed on protozoans: unicellular life forms that are often parasitic. In this review, we provide a historical perspective on the discovery of G4s, intertwined with their biological significance across the protozoan kingdom. This is a history in three parts: first, a period of discovery including the first characterisation of a G4 motif at the DNA level in ciliates (environmental protozoa); second, a period less dense in publications concerning protozoa, during which DNA G4s were discovered in both humans and viruses; and third, a period of renewed interest in protozoa, including more mechanistic work in ciliates but also in pathogenic protozoa. This last period has opened an exciting prospect of finding new anti-parasitic drugs to interfere with parasite biology, thus adding new compounds to the therapeutic arsenal.

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GIBSON, C. J., C. N. HAAS e J. B. ROSE. "Risk assessment of waterborne protozoa: current status and future trends". Parasitology 117, n.º 7 (novembro de 1999): 205–12. http://dx.doi.org/10.1017/s0031182099004746.

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Throughout the past decade much research has been directed towards identifying the occurrence, epidemiology, and risks associated with waterborne protozoa. While outbreaks are continually documented, sporadic cases of disease associated with exposure to low levels of waterborne protozoa are of increasing concern. Current methodologies may not be sensitive enough to define these low levels of disease. However, risk assessment methods may be utilised to address these low level contamination events. The purpose of this article is to provide an introduction to microbial risk assessment for waterborne protozoa. Risk assessment is a useful tool for evaluating relative risks and can be used for development of policies to decrease risks. Numerous studies have been published on risk assessment methods for pathogenic protozoa including Cryptosporidium and Giardia. One common notion prevails: microbial risk assessment presents interesting complications to the traditional chemical risk assessment paradigm. Single microbial exposures (non-threshold) are capable of causing symptomatic illness unlike traditional chemical exposures, which require a threshold to be reached. Due to the lack of efficient recovery and detection methods for protozoa, we may be underestimating the occurrence, concentration and distribution of these pathogenic micro-organisms. To better utilize the tool of microbial risk assessment for risk management practices, future research should focus in the area of exposure assessment.

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METFIES, KATJA, MARCO BERZANO, CHRISTIAN MAYER, PAUL ROOSKEN, CLAUDIO GUALERZI, LINDA MEDLIN e GERARD MUYZER. "An optimized protocol for the identification of diatoms, flagellated algae and pathogenic protozoa with phylochips". Molecular Ecology Notes 7, n.º 6 (novembro de 2007): 925–36. http://dx.doi.org/10.1111/j.1471-8286.2007.01799.x.

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Cain, Cody C., Alexis T. Henry, Robert H. Waldo, Lester J. Casida e Joseph O. Falkinham. "Identification and Characteristics of a NovelBurkholderia Strain with Broad-Spectrum Antimicrobial Activity". Applied and Environmental Microbiology 66, n.º 9 (1 de setembro de 2000): 4139–41. http://dx.doi.org/10.1128/aem.66.9.4139-4141.2000.

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ABSTRACT A Burkholderia strain isolated from soil is capable of inhibiting the growth of bacteria, plant-pathogenic fungi, pathogenic yeasts, and protozoa. Inhibition does not involve cell contact or the presence of living cells, suggesting that at least a substantial portion of the antimicrobial activity is due to the excretion of extracellular compounds.

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Hiatt, Robert A., Edward K. Markell e Ernest Ng. "How Many Stool Examinations are Necessary to Detect Pathogenic Intestinal Protozoa?" American Journal of Tropical Medicine and Hygiene 53, n.º 1 (1 de julho de 1995): 36–39. http://dx.doi.org/10.4269/ajtmh.1995.53.36.

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Miranda, Kildare, Wendell Girard-Dias e Wanderley de Souza. "Application of Analytical Electron Tomography to the Study of Pathogenic Protozoa". Microscopy and Microanalysis 20, S3 (agosto de 2014): 1314–15. http://dx.doi.org/10.1017/s1431927614008307.

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Bray, Patrick G., Michael P. Barrett, Stephen A. Ward e Harry P. de Koning. "Pentamidine uptake and resistance in pathogenic protozoa: past, present and future". Trends in Parasitology 19, n.º 5 (maio de 2003): 232–39. http://dx.doi.org/10.1016/s1471-4922(03)00069-2.

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de Koning, Harry P., Daniel J. Bridges e Richard J. S. Burchmore. "Purine and pyrimidine transport in pathogenic protozoa: From biology to therapy". FEMS Microbiology Reviews 29, n.º 5 (novembro de 2005): 987–1020. http://dx.doi.org/10.1016/j.femsre.2005.03.004.

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Benchimol, Marlene, Juan C. Engel, Kevin S. W. Tan e Wanderley de Souza. "Cell Biology of Pathogenic Protozoa and Their Interaction with Host Cells". BioMed Research International 2014 (2014): 1–2. http://dx.doi.org/10.1155/2014/143418.

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Campagnaro, Gustavo D., e Harry P. Koning. "Purine and pyrimidine transporters of pathogenic protozoa – conduits for therapeutic agents". Medicinal Research Reviews 40, n.º 5 (7 de março de 2020): 1679–714. http://dx.doi.org/10.1002/med.21667.

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Stevens, Jamie R., e Wendy C. Gibson. "The evolution of pathogenic trypanosomes". Cadernos de Saúde Pública 15, n.º 4 (outubro de 1999): 673–84. http://dx.doi.org/10.1590/s0102-311x1999000400002.

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In the absence of a fossil record, the evolution of protozoa has until recently largely remained a matter for speculation. However, advances in molecular methods and phylogenetic analysis are now allowing interpretation of the "history written in the genes". This review focuses on recent progress in reconstruction of trypanosome phylogeny based on molecular data from ribosomal RNA, the miniexon and protein-coding genes. Sufficient data have now been gathered to demonstrate unequivocally that trypanosomes are monophyletic; the phylogenetic trees derived can serve as a framework to reinterpret the biology, taxonomy and present day distribution of trypanosome species, providing insights into the coevolution of trypanosomes with their vertebrate hosts and vectors. Different methods of dating the divergence of trypanosome lineages give rise to radically different evolutionary scenarios and these are reviewed. In particular, the use of one such biogeographically based approach provides new insights into the coevolution of the pathogens, Trypanosoma brucei and Trypanosoma cruzi, with their human hosts and the history of the diseases with which they are associated.

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Lambrecht, Ellen, Julie Baré, Natascha Chavatte, Wim Bert, Koen Sabbe e Kurt Houf. "Protozoan Cysts Act as a Survival Niche and Protective Shelter for Foodborne Pathogenic Bacteria". Applied and Environmental Microbiology 81, n.º 16 (12 de junho de 2015): 5604–12. http://dx.doi.org/10.1128/aem.01031-15.

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ABSTRACTThe production of cysts, an integral part of the life cycle of many free-living protozoa, allows these organisms to survive adverse environmental conditions. Given the prevalence of free-living protozoa in food-related environments, it is hypothesized that these organisms play an important yet currently underinvestigated role in the epidemiology of foodborne pathogenic bacteria. Intracystic bacterial survival is highly relevant, as this would allow bacteria to survive the stringent cleaning and disinfection measures applied in food-related environments. The present study shows that strains of widespread and important foodborne bacteria (Salmonella enterica,Escherichia coli,Yersinia enterocolitica, andListeria monocytogenes) survive inside cysts of the ubiquitous amoebaAcanthamoeba castellanii, even when exposed to either antibiotic treatment (100 μg/ml gentamicin) or highly acidic conditions (pH 0.2) and resume active growth in broth media following excystment. Strain- and species-specific differences in survival periods were observed, withSalmonella entericasurviving up to 3 weeks inside amoebal cysts. Up to 53% of the cysts were infected with pathogenic bacteria, which were located in the cyst cytosol. Our study suggests that the role of free-living protozoa and especially their cysts in the persistence and epidemiology of foodborne bacterial pathogens in food-related environments may be much more important than hitherto assumed.

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Shemetova, Svetlana Aleksandrovna, Tatyana Vasilievna Nikeshina, Nina Vitalievna Polyanskaya, Gennadiy Leonidovich Shendo, Rudolf Sergeevich Arakelyan, Valeriya Sergeevna Korolkova e Khedi Bekkhanovna Artsueva. "Sanitary and parasitological state of water bodies of the Astrakhan region for 2011–2020". Sanitarnyj vrač (Sanitary Doctor), n.º 5 (1 de maio de 2021): 14–24. http://dx.doi.org/10.33920/med-08-2105-02.

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The article presents the material on the sanitary-parasitological state of water bodies of the Astrakhan region for 2011–2020. In total, during the analyzed period, laboratory studies were conducted on 77,017 samples taken from environmental objects (soil, water, flushes from solid household surfaces). The share of water samples in the structure of general sanitary and parasitological studies of the environment was 7.6 % (5858 samples), including unsatisfactory samples was 3.0 % (175 samples). The structure of positive findings in water samples was represented by 6 nosological forms of helminthiasis — 88.0 % (154 samples) and 3 nosoforms of protozoa — 12.0 %. Water samples were taken from various sources in Astrakhan and the Astrakhan region and examined for the presence of eggs and larvae of helminths, cysts of pathogenic intestinal protozoa and oocysts of cryptosporidia: water from open reservoirs, centralized water supply, swimming pools, waste water, water from wells and bottled water. As a result of the conducted studies, the results were obtained, indicating that the parasitic contamination of water bodies of the Astrakhan region remains very intense, as evidenced by positive findings in the form of eggs and larvae of helminths and cysts of pathogenic intestinal protozoa; the presence in the studied water samples of eggs and larvae of helminths and pathogenic protozoa cysts, evidence of the contamination of these objects feces of infected people (eggs broad tapeworm, Ascaris, opisthorchis, pinworms, Giardia cysts, amoebas and blastocyst) and animals (egg opistorchis, Toxocara, larvae strongylid); the presence of positive findings in the sewage samples indicates poor disinfestation data objects; the presence of parasitic agents in water samples taken from open reservoirs indicates that they are contaminated with the feces of infected animals and people, or that the object is contaminated with sewage and / or sewage.

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Coppellotti, Olimpia, Clara Fabris, Marina Soncin, Giulio Jori e Laura Guidolin. "Photosensitized Inactivation of Protozoa Pathogenic Agents of Water- and Vector-Borne Diseases". Forum on Immunopathological Diseases and Therapeutics 2, n.º 3 (2011): 247–54. http://dx.doi.org/10.1615/forumimmundisther.2011004382.

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Cano, Pedro, Alejandro Islas-Jácome, Ángeles Rangel-Serrano, Fernando Anaya-Velázquez, Felipe Padilla-Vaca, Elías Trujillo-Esquivel, Patricia Ponce-Noyola, Antonio Martínez-Richa e Rocío Gámez-Montaño. "In Vitro Studies of Chromone-Tetrazoles against Pathogenic Protozoa, Bacteria, and Fungi". Molecules 20, n.º 7 (8 de julho de 2015): 12436–49. http://dx.doi.org/10.3390/molecules200712436.

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Santos, Dilvani O., e Mécia M. Oliveira. "Effect of cAMP on macromolecule synthesis in the pathogenic protozoa Trypanosoma cruzi". Memórias do Instituto Oswaldo Cruz 83, n.º 3 (setembro de 1988): 287–92. http://dx.doi.org/10.1590/s0074-02761988000300004.

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Macromolecule synthesis of Trypanosoma cruzi in culture was monitored using radioactive tracers. Cells of different days in culture displayed a preferential incorporation of precursors as follows: 1 day for (³H)-thymidine cells; 3 days for (³H)-uridine cells, and 4 days for (³H)-leucine cells. Autoradiographic studies showed that (³H)-thymidine was incorporated in the DNA of both kinetoplast and nucleus in this order. Shifts in the intracellular content of cAMP either by addition of dibutyryl-cAMP or by stimulation of the adenylcyclase by isoproterenol, caused an inhibition in the synthesis of DNA, RNA and proteins. Addition to the T. cruzi cultures of these agents which elevate the intracellular content ofcAMP provoked an interruption of cell proliferation as a result of the impairment of macromolecule synthesis. A discrimination was observed among the stereoisomers of isoproterenol, the L configuration showing to be most active.

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Bower, Susan M. "Artificial culture of Labyrinthuloides haliotidis (Protozoa: Labyrinthomorpha), a pathogenic parasite of abalone". Canadian Journal of Zoology 65, n.º 8 (1 de agosto de 1987): 2013–20. http://dx.doi.org/10.1139/z87-306.

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Labyrinthuloides haliotidis was isolated from infected abalone (Haliotis kamtschatkana) and successfully cultured in minimum essential medium with 10% fetal calf serum at 10 °C for at least 1 year. On transfer to sea water, some subcultures produced numerous motile biflagellate zoospores while zoospore production of other subcultures was poor. On return to minimum essential medium, zoospores transformed into rapidly dividing vegetative forms. Labyrinthuloides haliotidis was not fastidious in its nutrient requirements and vegetative forms grew well in several different liquid media, on agar containing 10% bovine serum, and on pine pollen (Pinus contorta) in sea water. The mean diameter of the round vegetative forms often varied significantly (Student's t-test, P < 0.05) but the overall range in diameter (3.1 to 16.2 μm) observed in the various media was similar. Best growth occurred at 10 °C and in media made up with 30‰ sea water. No growth occurred at 28 °C or above, or in thioglycollate culture medium at 10 °C. Although L. haliotidis grew on pine pollen in sea water, zoosporoblasts and zoospores were not produced. The disappearance of precipitated proteins in agar medium around colonies of L. haliotidis and the destruction of host tissue around the parasite in infected abalone suggest that extracellular digestion occurs with this organism.

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Birkholtz, Lyn-Marie, Marni Williams, Jandeli Niemand, Abraham I. Louw, Lo Persson e Olle Heby. "Polyamine homoeostasis as a drug target in pathogenic protozoa: peculiarities and possibilities". Biochemical Journal 438, n.º 2 (12 de agosto de 2011): 229–44. http://dx.doi.org/10.1042/bj20110362.

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New drugs are urgently needed for the treatment of tropical and subtropical parasitic diseases, such as African sleeping sickness, Chagas' disease, leishmaniasis and malaria. Enzymes in polyamine biosynthesis and thiol metabolism, as well as polyamine transporters, are potential drug targets within these organisms. In the present review, the current knowledge of unique properties of polyamine metabolism in these parasites is outlined. These properties include prozyme regulation of AdoMetDC (S-adenosylmethionine decarboxylase) activity in trypanosomatids, co-expression of ODC (ornithine decarboxylase) and AdoMetDC activities in a single protein in plasmodia, and formation of trypanothione, a unique compound linking polyamine and thiol metabolism in trypanosomatids. Particularly interesting features within polyamine metabolism in these parasites are highlighted for their potential in selective therapeutic strategies.

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de Souza, Wanderley, Celso Sant’Anna e Narcisa L. Cunha-e-Silva. "Electron microscopy and cytochemistry analysis of the endocytic pathway of pathogenic protozoa". Progress in Histochemistry and Cytochemistry 44, n.º 2 (junho de 2009): 67–124. http://dx.doi.org/10.1016/j.proghi.2009.01.001.

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Breitling, Reinhard, Susanne Klingner, Nico Callewaert, Regina Pietrucha, Anett Geyer, Gunter Ehrlich, Regina Hartung et al. "Non-pathogenic trypanosomatid protozoa as a platform for protein research and production". Protein Expression and Purification 25, n.º 2 (julho de 2002): 209–18. http://dx.doi.org/10.1016/s1046-5928(02)00001-3.

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Prole, David L., e Colin W. Taylor. "Identification and Analysis of Putative Homologues of Mechanosensitive Channels in Pathogenic Protozoa". PLoS ONE 8, n.º 6 (13 de junho de 2013): e66068. http://dx.doi.org/10.1371/journal.pone.0066068.

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Beitz, Eric. "Aquaporin Water and Solute Channels from Malaria Parasites and Other Pathogenic Protozoa". ChemMedChem 1, n.º 6 (12 de junho de 2006): 587–92. http://dx.doi.org/10.1002/cmdc.200500105.

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Nikeshina, Tatyana V., Rudolf S. Arakelyan, Gennadii L. Shendo, Anna V. Kovalenko, Alexandra A. Kiseleva e Olga A. Arakelyants. "Contamination of water bodies of Astrakhan region with helminth-protozoan infestations". Perm Medical Journal 39, n.º 1 (15 de janeiro de 2022): 94–103. http://dx.doi.org/10.17816/pmj39194-103.

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Objective. To study and carry out the retrospective analysis of water contamination with helminth-protozoan infestations in Astrakhan Region for 2010-2019. Materials and methods. During the analyzed period, 80962 samples taken from environmental objects were examined. Results. The percentage of samples that did not meet sanitary and parasitological indicators was 1.2 % (951 samples). The proportion of water samples collected and examined for parasitological parameters (eggs and larvae of helminths, cysts of pathogenic intestinal protozoa and oocysts of cryptosporidia) was 7.5 % (6033 samples). Water samples were taken from various water sources: water from centralized water supply, water from swimming pools, water from open reservoirs, waste water, water from wells, and bottled water. Conclusions. To conclude, the results were obtained indicating that the absence of positive findings in water samples from central water supply facilities indicates a high-quality filtration and prevention of these objects; the presence of cysts of dysentery amoeba and dead strongylid larvae in water samples, swimming pools, as well as the presence of eggs and larvae of helminths and cysts of pathogenic intestinal protozoa in open reservoirs, indicates fecal contamination of these objects; the presence of positive findings in samples of wastewater and water from wells shows that reliable deworming and disinfection of wastewater is not provided at these facilities.

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Zacharia, Abdallah, Wajihu Ahmada, Anne H. Outwater, Billy Ngasala e Rob Van Deun. "Evaluation of Occurrence, Concentration, and Removal of Pathogenic Parasites and Fecal Coliforms in Three Waste Stabilization Pond Systems in Tanzania". Scientific World Journal 2019 (23 de outubro de 2019): 1–12. http://dx.doi.org/10.1155/2019/3415617.

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In Tanzania, waste stabilization ponds (WSPs) are employed to treat wastewater, and effluents are used for urban agricultural activities. The use of untreated or partially treated wastewater poses risks of disease transmission, including parasitic and bacterial infections, to exposed communities. Little is known about the occurrence, concentration, and removal of parasites and fecal coliform (FC) bacteria in WSPs in Tanzania. This study evaluates the occurrence and concentration of parasites and FCs in wastewater, the efficiency of WSPs in removing parasites and FCs, and the validity of using FCs as an indicator of parasites. This was a cross-sectional study conducted between February and August 2018. Wastewater samples were collected from three WSPs located in the Morogoro, Mwanza, and Iringa regions. APHA methods were used to test physicochemical parameters. The modified Bailenger method and Ziehl–Neelsen stain were used to analyse parasites. Membrane filtration method was used to analyse FCs. Data were analysed using IBM SPSS version 20. Helminth egg removal ranged from 80.8% to 100%. Protozoan (oo)cyst removal ranged from 98.8% to 99.9%. The Mwanza WSP showed the highest FC reduction (3.8 log units (100 mL)−1). Both the parasites and FCs detected in the effluents of assessed WSPs were of higher concentrations than World Health Organization and Tanzania Bureau of Standards limits, except for helminths in the Morogoro WSP and FCs in the Mwanza WSP. FCs were significantly correlated with protozoa (p<0.01) and predicted protozoa occurrence well (p=0.011). There were correlations between physicochemical parameters, parasites, and FC bacteria in the WSP systems. Inadequate performance of these systems may be due to lack of regular maintenance and/or systems operating beyond their capacity. FC indicators were observed to be a good alternative for protozoa monitoring, but not for helminths. Therefore, during wastewater quality monitoring, helminths should be surveyed independently.

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Radwan, Eman H., Amel Abd El Rahman Hassan, Wael M. Lotfy, Ahmed Abd El-Mawgood e Hala M. Mashaal. "The Prevalence of Intestinal Parasite Infection in El Behara Schoolchildren." International Journal of Limnology 1, n.º 1 (15 de junho de 2019): 33–51. http://dx.doi.org/10.14302/issn.2691-3208.ijli-19-2853.

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This study was conducted to evaluate the prevalence of intestinal parasite in schoolchildren in Damanhur, Egypt and some of its villages. The pathogenic enteric protozoa have been progressively involved in bargaining the soundness of a great many individuals, for the most part in creating nations. Mediations are being set up to control the dreariness and mortality because of these protozoan contaminations. A portion of these mediations target school going kids with regards to class based wellbeing intercession. The present examination concentrated on exploring the commonness of intestinal protozoan contaminations among younger students chose networks comprising of urban, urban-poor and per urban settlements in the Damanhour and a few towns. In the present work Giardia lamblia was the second usually identified protozoan with a diseases rate 10.4% among the analyzed cases. In the present examination generally speaking level of parasitic contaminations among the kids was 57.3%. It's viewed as Enterobius vermicularis was the most usually identified protozoan as it spoke to 4.1% of the parasitic diseases in the considered cases pursued by Ascaris lumbricoides; 1.4% and Giardia lamblia contaminations as they spoke to 0.6%; separately. The protozoa like Giardia and Cryptosporidium are regularly present in surface waters and cause episodes in this manner legitimately affecting human wellbeing.

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Taylor, Louise H., Sophia M. Latham e Mark E. J. woolhouse. "Risk factors for human disease emergence". Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 356, n.º 1411 (29 de julho de 2001): 983–89. http://dx.doi.org/10.1098/rstb.2001.0888.

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A comprehensive literature review identifies 1415 species of infectious organism known to be pathogenic to humans, including 217 viruses and prions, 538 bacteria and rickettsia, 307 fungi, 66 protozoa and 287 helminths. Out of these, 868 (61%) are zoonotic, that is, they can be transmitted between humans and animals, and 175 pathogenic species are associated with diseases considered to be ‘emerging’. We test the hypothesis that zoonotic pathogens are more likely to be associated with emerging diseases than non–emerging ones. Out of the emerging pathogens, 132 (75%) are zoonotic, and overall, zoonotic pathogens are twice as likely to be associated with emerging diseases than non–zoonotic pathogens. However, the result varies among taxa, with protozoa and viruses particularly likely to emerge, and helminths particularly unlikely to do so, irrespective of their zoonotic status. No association between transmission route and emergence was found. This study represents the first quantitative analysis identifying risk factors for human disease emergence.

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Verlinde, Christophe, Erkang Fan, Sayaka Shibata, Zhongsheng Zhang, Zhihua Sun, Wei Deng, Jennifer Ross et al. "Fragment-Based Cocktail Crystallography by the Medical Structural Genomics of Pathogenic Protozoa Consortium". Current Topics in Medicinal Chemistry 9, n.º 18 (1 de dezembro de 2009): 1678–87. http://dx.doi.org/10.2174/156802609790102383.

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