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Inflammasomes are cytosolic complexes that assemble in response to cellular stress or upon sensing microbial molecules, culminating in cytokine processing and an inflammatory form of cell death called pyroptosis. Inflammasomes are usually composed of a sensor molecule, an adaptor protein, and an inflammatory caspase, such as Caspase-1, which cleaves and activates multiple substrates, including Gasdermin-D, pro-IL-1ß, and pro-IL-18. Ultimately, inflammasome activation promotes inflammation and restriction of the microbial infection. In recent years, many studies have addressed the role of inflammasomes during fungal, bacterial, viral, and parasitic diseases, revealing sophisticated aspects of the host-pathogen interaction. In this review, we summarize recent advances on inflammasome activation in response to intracellular parasites, including Leishmania spp., Plasmodium spp., Trypanosoma cruzi, and Toxoplasma gondii.

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CRISPR/Cas evolved as an adaptive immune system in bacteria and archaea to inactivate foreign viral and plasmid DNA. However, the capacities of various CRISPR/Cas systems for precise genome editing based on sequence homology also allow their use as tools for genomic and epigenomic modification in eukaryotes. Indeed, these genetic characteristics have proven useful for disease modeling and testing the specific functions of target genes under pathological conditions. Moreover, recent studies provide compelling evidence that CRISPR/Cas systems could be useful therapeutic tools against human diseases, including cancer, monogenic disorders, and autoimmune disorders.HighlightsCRISPR/Cas evolved as an adaptive immune system in bacteria and archaea.CRISPR/Cas systems are nowadays used as tools for genomic modification.CRISPR/Cas systems could be useful therapeutic tools against human disease, including autoimmune conditions.

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Genome editing by CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 (CRISPR-associated gene 9) system has been transformative in biology. Originally discovered as an adaptive prokaryotic immune system, CRISPR/Cas9 has been repurposed for genome editing in a broad range of model organisms, from yeast to mammalian cells. Protist parasites are unicellular organisms producing important human diseases that affect millions of people around the world. For many of these diseases, such as malaria, Chagas disease, leishmaniasis and cryptosporidiosis, there are no effective treatments or vaccines available. The recent adaptation of the CRISPR/Cas9 technology to several protist models will be playing a key role in the functional study of their proteins, in the characterization of their metabolic pathways, and in the understanding of their biology, and will facilitate the search for new chemotherapeutic targets. In this work we review recent studies where the CRISPR/Cas9 system was adapted to protist parasites, particularly to Apicomplexans and trypanosomatids, emphasizing the different molecular strategies used for genome editing of each organism, as well as their advantages. We also discuss the potential usefulness of this technology in the green alga Chlamydomonas reinhardtii.

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Entre las enfermedades relacionadas con el agua según su uso se encuentran las causadas por sustancias químicas y por agentes biológicos. Dentro de estas últimas, las ocasionadas por bacterias y protozoarios patógenos incrementan cada día la lista de enfermedades emergentes y reemergentes. Los métodos de ensayo para la determinación de microorganismos patógenos en el agua no han variado mucho en los últimos años, principalmente para los indicadores bacterianos de contaminación fecal, y por lo general se realizan por métodos convencionales. Sin embargo, existen situaciones, sobre todo en la aparición de brotes de enfermedades, en las que se hace necesario detectar el microorganismo patógeno en agua como posible agente causal, por lo que se ha recomendado el uso de métodos rápidos y confiables. Dentro de estos se encuentran los inmunoensayos, de los cuales los métodos por precipitación y aglutinación, los enzimoinmunoensayos, las técnicas de inmunofluorescencia directa e indirecta y la citometría de flujo son muy útiles en la detección de microorganismos en agua. Mención aparte merece la separación inmunomagnética o inmunocaptura como paso previo a otras técnicas avanzadas. Nos proponemos con este trabajo exponer las ventajas y desventajas de estos métodos, los principios en los cuales se basan y ejemplificar algunos de los más utilizados en microbiología de aguas, así como recalcar su importancia(AU)

Diseases related to the use of water may be caused by chemical substances or biological agents. Among the latter, a prominent role is played by pathogenic bacteria and protozoa, which constantly add to the list of emerging and re-emerging diseases. Assay methods to identify pathogenic microorganisms in water have not changed much in recent years, particularly with respect to bacterial indicators of fecal contamination, and tests are usually conducted by conventional methods. However, in certain situations, especially when a disease outbreak occurs, it is necessary to determine what pathogenic microorganism is the possible causal agent, and quick, reliable methods have been recommended to achieve this aim. These include immunoassays, among which precipitation and agglutination methods, enzyme immunoassays, direct and indirect immunofluorescence techniques and flow cytometry have proven very useful to detect microorganisms in water. Special mention should be made of immunomagnetic separation or immunocapture as a step preceding other advanced techniques. The present paper is aimed at presenting the advantages and disadvantages of these methods, as well as the principles on which they are based. Examples are provided of the methods most commonly used in water microbiology, highlighting their importance(AU)

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Entre las enfermedades relacionadas con el agua según su uso se encuentran las causadas por sustancias químicas y por agentes biológicos. Dentro de estas últimas, las ocasionadas por bacterias y protozoarios patógenos incrementan cada día la lista de enfermedades emergentes y reemergentes. Los métodos de ensayo para la determinación de microorganismos patógenos en el agua no han variado mucho en los últimos años, principalmente para los indicadores bacterianos de contaminación fecal, y por lo general se realizan por métodos convencionales. Sin embargo, existen situaciones, sobre todo en la aparición de brotes de enfermedades, en las que se hace necesario detectar el microorganismo patógeno en agua como posible agente causal, por lo que se ha recomendado el uso de métodos rápidos y confiables. Dentro de estos se encuentran los inmunoensayos, de los cuales los métodos por precipitación y aglutinación, los enzimoinmunoensayos, las técnicas de inmunofluorescencia directa e indirecta y la citometría de flujo son muy útiles en la detección de microorganismos en agua. Mención aparte merece la separación inmunomagnética o inmunocaptura como paso previo a otras técnicas avanzadas. Nos proponemos con este trabajo exponer las ventajas y desventajas de estos métodos, los principios en los cuales se basan y ejemplificar algunos de los más utilizados en microbiología de aguas, así como recalcar su importancia

Diseases related to the use of water may be caused by chemical substances or biological agents. Among the latter, a prominent role is played by pathogenic bacteria and protozoa, which constantly add to the list of emerging and re-emerging diseases. Assay methods to identify pathogenic microorganisms in water have not changed much in recent years, particularly with respect to bacterial indicators of fecal contamination, and tests are usually conducted by conventional methods. However, in certain situations, especially when a disease outbreak occurs, it is necessary to determine what pathogenic microorganism is the possible causal agent, and quick, reliable methods have been recommended to achieve this aim. These include immunoassays, among which precipitation and agglutination methods, enzyme immunoassays, direct and indirect immunofluorescence techniques and flow cytometry have proven very useful to detect microorganisms in water. Special mention should be made of immunomagnetic separation or immunocapture as a step preceding other advanced techniques. The present paper is aimed at presenting the advantages and disadvantages of these methods, as well as the principles on which they are based. Examples are provided of the methods most commonly used in water microbiology, highlighting their importance

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Cells release extracellular vesicles in response to external factors or in a physiological way. Microvesicles and exosomes originate in cells in different ways and, depending on their contents, may have multiple biological effects on other cells and the environment. The host cell-parasite relationship could be changed dramatically by the plasticity of a new type of communication through extracellular vesicles. In the present paper, we discuss how protozoans use this new resource to evade the immune system and establish infection.

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O trabalho objetivou estimar a frequência de rebanhos caprinos soropositivos ao Toxoplasma gondii no município de São Luís, Maranhão, Brasil, através do método ELISA indireto (Enzime Linked Immunosorbent Assay). Utilizaram-se o programa Epi Info 3.5.1 e os Testes Qui-quadrado e Exato de Fisher, para análise dos dados. Verificou-se que, dos 92 soros analisados, 34 (36,95%) eram soropositivos e 58 (63,05%) soronegativos. Em relação às propriedades de rebanhos caprinos pesquisadas, verificou-se soropositividade em oito (80%) das dez utilizadas no estudo. Das propriedades com condições de estocagem de alimento, 24 propriedades foram consideradas ruins e quatorze (15,3%) foram soropositivas para T. gondii, verificando-se associação significativa (p < 0,05). A exploração leiteira apresentou associação significativa (p = 0,0478). A de corte mostrou percentual significativo: do total de dezenove animais, onze (57,89%) foram soropositivos. Em relação ao tipo de alimento, verificou-se (14) 58,33% de soropositividade para os animais submetidos à alimentação com forragem (p < 0,05), considerando que o fornecimento apenas de forragem como fonte de alimentação oferece risco, por ser uma fonte de infecção por T. gondii. No que se refere ao destino do material abortado, que é fator relevante, constatou-se que nenhum dos produtores realiza o destino adequado para esse material, o que muitas vezes não elimina a presença do fator de risco, verificando-se soropositividade e associação significativa (p < 0,05). Não se verificaram neste estudo diferenças significativas na frequência do T. gondii, com relação ao sexo e faixa etária dos caprinos.

The objective of this work was to assess the frequency of Toxoplasma gondii seropotive goat herds in the municipality of São Luís, Maranhão, Brazil. The detection of anti-T.gondii was performed by the serological indirect ELISA method (Enzyme Linked Immunosorbent Assay). The data were analyzed using Epi Info 3.5.1 and subjected to chi-square and Fisher’s exact test. From 92 sera tested, 34 (36.95%) were seropositive and 58 (63.05%) seronegative. From 10 properties of goat herds surveyed in the municipality of São Luís, MA, seropositivity was found in eight (80%) of them. Regarding the conditions of storage of food, from 24 properties considered poor, 14 (15.3%) were seropositive for T. gondii, with a significant association (p <0.05). Milk production also had significant association (p = 0.0478), and beef production presented significant percentage: from 19 animals, 11 (57.89) were seropositive. As regards the type of food, (14) 58.33% of seropositivity was verified within the animals fed forage (p <0.05). The aborted material is also a relevant factor found in this study, considering none of the producers gave the appropriate destination for this material. This behavior does not often eliminate the presence of the risk factor, then seropositivity and association (p <0.05) can be verified. No significant differences were observed in the frequency of T. gondii, related to gender and age of goats.

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O trabalho objetivou estimar a frequência de rebanhos caprinos soropositivos ao Toxoplasma gondii no município de São Luís, Maranhão, Brasil, através do método ELISA indireto (Enzime Linked Immunosorbent Assay). Utilizaram-se o programa Epi Info 3.5.1 e os Testes Qui-quadrado e Exato de Fisher, para análise dos dados. Verificou-se que, dos 92 soros analisados, 34 (36,95%) eram soropositivos e 58 (63,05%) soronegativos. Em relação às propriedades de rebanhos caprinos pesquisadas, verificou-se soropositividade em oito (80%) das dez utilizadas no estudo. Das propriedades com condições de estocagem de alimento, 24 propriedades foram consideradas ruins e quatorze (15,3%) foram soropositivas para T. gondii, verificando-se associação significativa (p < 0,05). A exploração leiteira apresentou associação significativa (p = 0,0478). A de corte mostrou percentual significativo: do total de dezenove animais, onze (57,89%) foram soropositivos. Em relação ao tipo de alimento, verificou-se (14) 58,33% de soropositividade para os animais submetidos à alimentação com forragem (p < 0,05), considerando que o fornecimento apenas de forragem como fonte de alimentação oferece risco, por ser uma fonte de infecção por T. gondii. No que se refere ao destino do material abortado, que é fator relevante, constatou-se que nenhum dos produtores realiza o destino adequado para esse material, o que muitas vezes não elimina a presença do fator de risco, verificando-se soropositividade e associação significativa (p < 0,05). Não se verificaram neste estudo diferenças significativas na frequência do T. gondii, com relação ao sexo e faixa etária dos caprinos.(AU)

The objective of this work was to assess the frequency of Toxoplasma gondii seropotive goat herds in the municipality of São Luís, Maranhão, Brazil. The detection of anti-T.gondii was performed by the serological indirect ELISA method (Enzyme Linked Immunosorbent Assay). The data were analyzed using Epi Info 3.5.1 and subjected to chi-square and Fishers exact test. From 92 sera tested, 34 (36.95%) were seropositive and 58 (63.05%) seronegative. From 10 properties of goat herds surveyed in the municipality of São Luís, MA, seropositivity was found in eight (80%) of them. Regarding the conditions of storage of food, from 24 properties considered poor, 14 (15.3%) were seropositive for T. gondii, with a significant association (p <0.05). Milk production also had significant association (p = 0.0478), and beef production presented significant percentage: from 19 animals, 11 (57.89) were seropositive. As regards the type of food, (14) 58.33% of seropositivity was verified within the animals fed forage (p <0.05). The aborted material is also a relevant factor found in this study, considering none of the producers gave the appropriate destination for this material. This behavior does not often eliminate the presence of the risk factor, then seropositivity and association (p <0.05) can be verified. No significant differences were observed in the frequency of T. gondii, related to gender and age of goats.(AU)

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Toll-like receptors (TLRs) have emerged as a major receptor family involved in non-self recognition. They have a vital role in triggering innate immunity and orchestrate the acquired immune response during bacterial and viral infection. However, the role of TLRs during infection with protozoan pathogens is less clear. Nevertheless, our understanding of how these parasitic microorganisms engage the host TLR signalling system has now entered a phase of rapid expansion. This Review describes recent insights into how parasitic protozoans are sensed by TLR molecules, and how the TLR system itself can be targeted by these microbial pathogens for their own survival.

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In complex organisms, apoptosis is a constitutive cell death process that is involved in physiological regulation of cell numbers and that can also be induced in the course of inflammatory and immune responses. Neutrophils are among the first cells recruited during inflammation. Neutrophils constitutively die by apoptosis at inflamed sites, and are ingested by macrophages. Recent studies investigated how phagocytic clearance of senescent neutrophils influences the survival of intracellular protozoan parasites that have been phagocytosed by, or have invaded phagocytes. The results indicate that neutrophil clearance plays an unexpected role in regulation of intramacrophagic protozoan parasite infection.

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Major advances have recently been achieved in the area of microbial recognition by the innate immune system. In this Forum, we discuss important issues related to innate recognition of bacteria and protozoan parasites. In particular, we highlight the structural characterization of pathogen-associated molecular patterns (PAMPs); the definition of the receptors required for recognition of PAMPs, especially the Toll-like receptors (TLRs); the signaling pathways triggered by PAMPs/PAMPs receptor interaction; and the functional consequences of these interactions for pathogenesis during microbial infection.

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Being an intracellular pathogen demands being able to invade a host cell, to circumvent the host immune response and to survive in the intracellular environment. Pore-forming proteins are among the innumerable tools used by intracellular microorganisms to achieve these goals. Remarkably, this seems to be a multipurpose group of proteins that can act in several ways. Making channels may signify entering into host cells, inhibiting phagocytosis, escaping phagosomes or promoting pathogen dissemination. In certain cases, pore-forming proteins are double-edged tools and may benefit the host by eliminating infected cells and/or inducing inflammation.

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Apoptosis, a form of programmed cell death (PCD), plays a central role in normal tissue development as well as in the pathogenesis of different diseases. PCD is responsible for the non-inflammatory physiological elimination of potentially harmful or unnecessary cells during embryogenesis, and for the proper functioning of continuous cell renewal systems in adult organisms. Maturation of the immune system and the specific immune response are examples of situations where PCD plays important roles. This review discusses the importance of apoptosis in two fundamental elements of a host-parasite interaction: the parasite (Section 1), and the host's immune response (Section 2). Section 1 discusses questions raised by the description of apoptosis in unicellular eukaryotes, such as the evolutionary origin of the molecular components of PCD, its role in the emergence and maintenance of parasitism, and the constraints of a multicellular organization for the proper operation of a cell death programme. The proposal is that PCD can occur in any situation where living cells display features of an organized network which operates through interactions within themselves and/or with elements of their environment. The possibility is also discussed that evolutionary relics of a complete cell death system may operate in unicellular parasites with functions other than inducing cell death. Section 2 reviews data on the mechanisms of host-cell PCD and the consequences of this phenomenon in host defence and pathogenesis. Infectious agents, from viruses to parasites, can either delay or induce apoptosis of different types of host cells. Apoptosis following lymphocyte polyclonal activation and stimulation of peripheral T lymphocytes, as a result of the engagement of specific counter-receptor systems, is of special interest for defining host immunocompetence and mechanisms of immunopathology.

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Glycosylphosphatidylinositol (GPI) anchor and glycoinositolphospholipid (GIPL) are abundant molecules present in the membrane of parasitic protozoa that are common etiologic agents of medical and veterinary diseases. Recent studies have documented the immunostimulatory/regulatory activity of protozoan-derived GPI-anchors and related structures. Among the bioactivity displayed by the protozoan-derived GPI-anchor is the ability to elicit the synthesis of pro-inflammatory cytokines as well as nitric oxide by host macrophages. In contrast, at high concentrations GIPL and lipophosphoglycan (LPG) derived from protozoan parasites suppress several functions of the host immune system. Additionally, the protozoan-derived GPI-anchor and GIPL have been shown to serve as targets for both specific B and NK-T lymphocyte responses. This information extends our knowledge about parasite molecules that stimulate/regulate the host immune system during protozoan infection. The identification of receptor(s) and signaling pathways triggered by these GPI-related glycolipids may provide new insights for the development of therapies that inhibit detrimental immune responses or potentiate beneficial immune responses observed during infection with protozoan parasites.

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The discovery of the superantigens (SAgs) offered new insights on the interaction between microorganisms and the host immune system. Associated to Major Histocompatibility Complex (MHC) class II molecules, SAgs bind to the variable domain of the beta chain (V beta) of the TCR alpha beta engaged in the family specificity of lymphocytes. Therefore, these molecules are able to activate a high number of T lymphocytes as well as surface MHC class II bearing cells, leading to an overriding release of cytokines and inflammatory mediators, which have been related to their toxic effects. Endogenous SAgs are encoded by murine tumor proviruses (Mtv) which are integrated in the genome of mice. Bacteria and viruses produce exogenous SAgs and those related to food poisoning have been widely studied. The presence of parasite SAgs is still unclear and further studies are required to establish their existence and effects on the corresponding infections.

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El descubrimiento de los superatígenos (SAgs) aportó nuevos conceptos en el estudio de las interacciones entre los microorganismos y el sistema inmune. Se trata de moléculas que, asociadas a las de Clase II del Complejo Mayor de Histocompatibilidad (CMH), se unen al dominio variable de la cadena Beta Vbeta) del receptor de antígenos Ags) de los linfocitos T alphaBeta (TCRalphaBeta) que les confiere la especialidad de familia. Así, los SAgs son capaces de activar a un alto número de linfocitos T y de células portadoras de las moléculas de Classe II del CMH, generando una masiva liberación de linfoquinas y mediadores inflamatorios que ha sido relaciona con sus efectos tóxicos. Los SAgs endógenos están codificados por los provirus de tumores murinos (Mtv) que se hallan integrados al genoma de los ratones. Los exógenos son producidos por bacterias y virus, siendo los mejor caracterizados los relacionados con las intoxicaciones alimentarias. Aun no se han hallado datos concluyentes en cuanto a la existencia de SAgs de parásitos y se requieren estudos más detallados para establecer su presencia y posible efecto en las infecciones parasitarias. (AU)

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El descubrimiento de los superatígenos (SAgs) aportó nuevos conceptos en el estudio de las interacciones entre los microorganismos y el sistema inmune. Se trata de moléculas que, asociadas a las de Clase II del Complejo Mayor de Histocompatibilidad (CMH), se unen al dominio variable de la cadena Beta Vbeta) del receptor de antígenos Ags) de los linfocitos T alphaBeta (TCRalphaBeta) que les confiere la especialidad de familia. Así, los SAgs son capaces de activar a un alto número de linfocitos T y de células portadoras de las moléculas de Classe II del CMH, generando una masiva liberación de linfoquinas y mediadores inflamatorios que ha sido relaciona con sus efectos tóxicos. Los SAgs endógenos están codificados por los provirus de tumores murinos (Mtv) que se hallan integrados al genoma de los ratones. Los exógenos son producidos por bacterias y virus, siendo los mejor caracterizados los relacionados con las intoxicaciones alimentarias. Aun no se han hallado datos concluyentes en cuanto a la existencia de SAgs de parásitos y se requieren estudos más detallados para establecer su presencia y posible efecto en las infecciones parasitarias.

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