Trichomonas vaginalis adherence phenotypes and extracellular vesicles impact parasite survival in a novel in vivo model of pathogenesis.

Trichomonas vaginalis is a human infective parasite responsible for trichomoniasis-the most common, non-viral, sexually transmitted infection worldwide. T. vaginalis resides exclusively in the urogenital tract of both men and women. In women, T. vaginalis has been found colonizing the cervix and vaginal tract while in men it has been identified in the upper and lower urogenital tract and in secreted fluids such as semen, urethral discharge, urine, and prostatic fluid. Despite the over 270 million cases of trichomoniasis annually worldwide, T. vaginalis continues to be a highly neglected organism and thus poorly studied. Here we have developed a male mouse model for studying T. vaginalis pathogenesis in vivo by delivering parasites into the murine urogenital tract (MUT) via transurethral catheterization. Parasite burden was assessed ex-vivo using a nanoluciferase-based gene expression assay which allowed quantification of parasites pre- and post-inoculation. Using this model and read-out approach, we show that T. vaginalis can be found within MUT tissue up to 72 hrs post-inoculation. Furthermore, we also demonstrate that parasites that exhibit increased parasite adherence in vitro also have higher parasite burden in mice in vivo. These data provide evidence that parasite adherence to host cells aids in parasite persistence in vivo and molecular determinants found to correlate with host cell adherence in vitro are applicable to infection in vivo. Finally, we show that co-inoculation of T. vaginalis extracellular vesicles (TvEVs) and parasites results in higher parasite burden in vivo. These findings confirm our previous in vitro-based predictions that TvEVs assist the parasite in colonizing the host. The establishment of this pathogenesis model for T. vaginalis sets the stage for identifying and examining parasite factors that contribute to and influence infection outcomes.

Effect of BaltPLA2, a phospholipase A2 from Bothrops alternatus snake venom, on the viability of cells infected with dengue virus.

Dengue fever is considered a major public health problem in tropical and subtropical regions. Our study analyzed the effect of BaltPLA2, a phospholipase A2 from Bothrops alternatus snake venom, on the viability of cells infected with Dengue virus. In presence of BaltPLA2, the viability of infected cells increased significantly in virucidal, post-treatment, and adsorption assays. Although preliminary these results reveal the need for further studies to investigated whether BaltPLA2 has antiviral activity against Dengue virus.

Role of TLR2/MyD88 in the production of specific IgM and IgG antibodies during the immunization of mice against Neospora caninum.

Neospora caninum is a parasite relevant to the veterinary field. Innate and adaptive responses against N. caninum induce effector mechanisms that limit parasite replication, but little is known about their role in humoral response. Our work aimed to verify whether key molecules in the TLR2/MyD88-mediated response would impact the production of specific IgM and IgG antibodies in mice during immunization with soluble antigens of N. caninum. We observed that lack of IFN-gamma did not negatively affect the production of specific antibodies. However, mice genetically deficient in Toll-like receptor 2, Myeloid differentiation factor 88, Interleukin 12 and inducible nitric oxide synthase presented significant decrease in antibody levels against N. caninum antigens, which also reflected in the diversity of the antigen recognized by their serum. In that sense, we show here that molecules within this innate recognition pathway may present a direct impact in the induction of an antibody response against N. caninum.

Enzyme engineering and its industrial applications.

Recently, there has been an increase in the demand for enzymes with modified activity, specificity, and stability. Enzyme engineering is an important tool to meet the demand for enzymes adjusted to different industrial processes. Knowledge of the structure and function of enzymes guides the choice of the best strategy for engineering enzymes. Each enzyme engineering strategy, such as rational design, directed evolution, and semi-rational design, has specific applications, as well as limitations, which must be considered when choosing a suitable strategy. Engineered enzymes can be optimized for different industrial applications by choosing the appropriate strategy. This review features engineered enzymes that have been applied in food, animal feed, pharmaceuticals, medical applications, bioremediation, biofuels, and detergents.

COVID-19 in oncology palliative care: psychological stress from the perspective of psychodynamics at work.

BACKGROUND: Identify the main stressors of the nursing team in assisting patients in oncology palliative care with suspicions and confirmed for COVID-19. METHODS: Qualitative, descriptive and exploratory study with theoretical framework in the psychodynamics of work, carried out in the emergency and hospitalization sector of a national reference center for cancer treatment in Rio de Janeiro/Brazil. The semi-structured interview was used to collect the data, from April to May 2020. The data were organized and analyzed using the Collective Subject Discourse (CSD) method with the aid of the Qualiquantisoft® software. RESULTS: Twenty members of the nursing team participated (10 nurses and 10 nursing technicians). After the analysis, three CSDs with their respective central ideas (CI) emerged. The CSD software, Qualiquantisoft®, also provided a quantitative analysis of the responses, in which 12 (60%) of the respondents believe that the main stressors are associated with work organization, 6 (30%) of the respondents believe that the main stressors are associated to work relationships and 2 (10%) of respondents believe that the main stressors are associated with working conditions. CONCLUSIONS: The adaptations that took place in the management of care and in the organization of work, to better serve patients in oncology palliative care with suspicions and confirmed for COVID-19, brought greater impact and psychological stress on the nursing team. Considering all the difficulties and influences that the nursing team members are facing in this pandemic moment by COVID-19 associated with palliative oncology care, it is believed that identifying the source of the psychological stress presented by them may contribute to them have a more effective, humanized and holistic care, in addition to spreading knowledge to nursing and other segments of the health area and bringing subsidies to other scientific productions, as well as highlighting the importance of early detection of psychological stress as a way of preventing impacts physical and psychosocial problems caused by work.

TNF-TNFR1 Signaling Enhances the Protection Against Neospora caninum Infection.

Neospora caninum is a protozoan associated with abortions in ruminants and neuromuscular disease in dogs. Classically, the immune response against apicomplexan parasites is characterized by the production of proinflammatory cytokines, such as IL-12, IFN-γ and TNF. TNF is mainly produced during the acute phases of the infections and binds to TNF receptor 1 (CD120a, p55, TNFR1) activating a variety of cells, hence playing an important role in the induction of the inflammatory process against diverse pathogens. Thus, in this study, we aimed to evaluate the role of TNF in cellular and humoral immune responses during N. caninum infection. For this purpose, we used a mouse model of infection based on wildtype (WT) and genetically deficient C57BL/6 mice in TNFR1 (Tnfr1-/-). We observed that Tnfr1-/- mice presented higher mortality associated with inflammatory lesions and increased parasite burden in the brain after the infection with N. caninum tachyzoites. Moreover, Tnfr1-/- mice showed a reduction in nitric oxide (NO) levels in vivo. We also observed that Tnfr1-/- mice showed enhanced serum concentration of antigen-specific IgG2 subclass, while IgG1 production was significantly reduced compared to WT mice, suggesting that TNFR1 is required for regular IgG subclass production and antigen recognition. Based on our results, we conclude that the TNF-TNFR1 complex is crucial for mediating host resistance during the infection by N. caninum.

Estresse da equipe de enfermagem em cuidados paliativos no enfrentamento da COVID-19 / Estrés del equipo de enfermería de cuidados paliativos en el enfrentamiento a la COVID-19 / Stress in palliative care nursing staff while coping with COVID-19

Resumo Objetivo Identificar a prevalência do estresse ocupacional dos profissionais de enfermagem que atuam em cuidados paliativos, durante a pandemia pelo SARS-CoV-2 e fatores sociodemográficos e ocupacionais associados. Métodos Trata-se de um estudo transversal, de abordagem quantitativa, realizado em uma unidade de atendimento a pacientes em cuidados paliativos oncológicos exclusivos, de um hospital oncológico público de referência nacional. A coleta de dados foi realizada entre os meses de abril e maio de 2020, utilizando dois instrumentos. Na análise dos dados foi utilizado o modelo de regressão de Poisson, com variância robusta. Resultados A amostra foi composta por 71 profissionais, que atuaram no atendimento à pacientes suspeitos ou com diagnóstico confirmado de COVID-19. O desfecho médio/alto nível de estresse foi prevalente em 42,2% dos profissionais, com maior predominância entre enfermeiros (65,0%), que exercem suas atividades no período diarista/diurno (55,2%) e que atuam há mais de oito anos em cuidados paliativos (45,1%). Apenas as variáveis "cargo" e "morar sozinho" apresentaram associação significativa ao estresse médio/alto. Conclusão Diante dos resultados é importante que as instituições busquem medidas por meio de intervenções psicológicas e ocupacionais que possam reduzir os impactos mentais gerados pela atuação durante a COVID-19. Sugere-se maior estresse entre os enfermeiros, pois se envolvem em questões assistenciais e burocráticas, o que aumenta sua responsabilidade perante a equipe, e aos profissionais que residem sozinhos devido aos impactos gerados pelo isolamento e falta de apoio familiar próximo.

Resumen Objetivo Identificar la prevalencia del estrés laboral de los profesionales de enfermería que actúan en cuidados paliativos, durante la pandemia del SARS-CoV-2 y factores sociodemográficos y laborales asociados. Métodos Se trata de un estudio transversal, de enfoque cuantitativo, realizado en una unidad de atención a pacientes en cuidados paliativos oncológicos exclusivos, de un hospital oncológico público de referencia nacional. La recopilación de datos fue realizada entre los meses de abril y mayo de 2020, mediante la utilización de dos instrumentos. En el análisis de los datos se utilizó el modelo de regresión de Poisson, con varianza robusta. Resultados La muestra estuvo compuesta por 71 profesionales que actuaban en la atención a pacientes con sospecha o diagnóstico confirmado de COVID-19. El resultado de nivel de estrés medio/alto fue prevalente en el 42,2 % de los profesionales, con una mayor predominancia entre enfermeros (65,0 %), que ejercen sus actividades en el período diurno (55,2 %) y que actúan hace más de ocho años en cuidados paliativos (45,1 %). Solamente las variables "cargo" y "vivir solo" presentaron una asociación significativa con el estrés medio/alto. Conclusión Ante los resultados obtenidos, es importante que las instituciones busquen medidas a través de intervenciones psicológicas y laborales para reducir los impactos mentales generados por el trabajo durante la COVID-19. Se sugiere que existe mayor estrés entre los enfermeros, ya que están involucrados en cuestiones asistenciales y burocráticas, lo que aumenta su responsabilidad ante el equipo, y los profesionales que viven solos debido a los impactos generados por el aislamiento y la falta de apoyo familiar cercano.

Abstract Objective To identify the prevalence of occupational stress among nursing professionals working in palliative care during the SARS-CoV-2 pandemic, and associated sociodemographic and occupational factors. Methods This was a cross-sectional study with a quantitative approach, conducted in an exclusive oncologic palliative care unit of a public oncology hospital of national reference. Data collection was performed between April and May of 2020, using two instruments. The Poisson regression model with robust variance was used for data analysis. Results The sample was composed of 71 professionals, working with patients suspected of or with a confirmed diagnosis of COVID-19. The medium/high level of stress outcome was prevalent in 42.2% of professionals, with higher prevalence among nurses (65.0%), who worked during the day shift (55.2%) and who had worked for more than eight years in palliative care (45.1%). Only the variables "position" and "living alone" showed a significant association with medium/high stress. Conclusion According the results, institutions must develop psychological and occupational interventions that can reduce the mental impact generated by nursing work during COVID-19. Increased stress was found among nurses, as they are involved in care and bureaucratic issues, which adds to their responsibility to the team, and among professionals who lived alone, due to impact generated by isolation and lack of close family support.

Covid-19 e suas influências psíquicas na percepção da equipe de enfermagem da atenção paliativa oncológica / Covid-19 y sus influencias psíquicas en la percepción del equipo de enfermería de la atención paliativa oncológica / Covid-19 and its psychical influences on the perception of the nursing staff of oncological palliative care

RESUMO Objetivo: identificar as principais influências psíquicas na percepção da equipe de Enfermagem na atenção paliativa oncológica durante a pandemia da COVID-19. Método: estudo interpretativo de abordagem qualitativa com referencial teórico na psicodinâmica do trabalho de Christophe Dejours. Compuseram a amostra 20 membros da equipe de Enfermagem que atuam na assistência de pacientes em cuidados paliativos oncológicos suspeitos e confirmados para COVID-19. Desenvolvido em uma unidade hospitalar especializada em cuidados paliativos oncológicos na cidade do Rio de Janeiro/Brasil. Foram realizadas entrevistas semiestruturadas e analisadas com base no referencial metodológico do discurso do sujeito coletivo (DSC). Resultados: emergiram dois discursos do DSC com suas ideias centrais: DSC1 - "influências psíquicas negativas da assistência paliativa oncológica durante a pandemia pela COVID-19 na percepção da equipe de Enfermagem"; e DSC2 - "influências psíquicas positivas da assistência paliativa oncológica durante a pandemia pela COVID-19 na percepção da equipe de Enfermagem". Conclusão: pôde-se perceber que a carga emocional demandada por esses profissionais,bem como tudo que está envolvido no processo do enfrentamento dessa pandemia, apresenta importante relação com o aparecimento dos sintomas que podem desencadear a síndrome de burnout. Por outro lado, foi possível identificar fatores positivos relacionados ao bem-estar profissional nesse momento de pandemia e fatores protetivos à saúde do trabalhador, tal como se manter na mesma equipe de trabalho visando ao apoio mútuo.

RESUMEN Objetivo: identificar las principales influencias psíquicas en la percepción del equipo de Enfermería en la atención paliativa oncológica durante la pandemia de la COVID-19. Método: estudio interpretativo con enfoque cualitativo con referencia teórica en la psicodinámica del trabajo de Christophe Dejours. Compusieron la muestra 20 miembros del equipo de Enfermería que actúan en la asistencia de pacientes en cuidados paliativos oncológicos sospechosos y confirmados para COVID-19. Desarrollado en una unidad hospitalaria especializada en cuidados oncológicos paliativos, en la ciudad de Rio de Janeiro/Brasil. Se realizaron entrevistas semiestructuradas y analizadas en base al referencial metodológico del Discurso del Sujeto Colectivo. Resultados: surgieron dos discursos del sujeto colectivo (DSC) con sus ideas centrales: DSC1 - "Influencias psíquicas negativas de la asistencia paliativa oncológica durante la pandemia por COVID-19 en la percepción del equipo de Enfermería" y DSC2 - "Influencias psíquicas positivas de la asistencia paliativa oncológica durante la pandemia por COVID-19 en la percepción del equipo de Enfermería". Conclusión: se pudo percibir que la carga emocional demandada por estos profesionales, así como todo que está involucrado en el proceso de afrontamiento de esta pandemia, presentan importante relación con la aparición de los síntomas que pueden desencadenar el síndrome de Burnout. Por otro lado, fue posible identificar factores positivos relacionados con el bienestar profesional en este momento de pandemia y factores protectores a la salud del trabajador, como permanecer en el mismo equipo de trabajo buscando el apoyo mutuo.

ABSTRACT Objective: to identify the main psychological influences on the perception of the Nursing staff in oncological palliative care during the COVID-19 pandemic. Method: interpretative study with a qualitative approach with theoretical framework in the psychodynamics of Christophe Dejours' work. The sample comprised 20 members of the Nursing staff who work to assist patients in oncological palliative care suspected and confirmed for COVID-19. Developed in a hospital unit specialized in oncological palliative care in the city of Rio de Janeiro/Brazil. Semi-structured interviews were conducted and analyzed based on the methodological framework of the discourse of the collective subject (CSD). Results: two CSD speeches emerged with their central ideas: CSD1 - "negative psychological influences of oncological palliative care during the pandemic by COVID-19 in the perception of the Nursing staff"; and CSD2 - "Positive psychological influences of oncological palliative care during the pandemic by COVID-19 in the perception of the Nursing staff". Conclusion: it was possible to notice that the emotional load demanded by these professionals, as well as everything involved in the process of coping with this pandemic, has an important relationship with the appearance of symptoms that can trigger the burnout syndrome. On the other hand, it was possible to identify positive factors related to professional well-being during the pandemic and protective factors to the workers' health, such as staying in the same work team aiming at mutual support.

Interplay Between Reactive Oxygen Species and the Inflammasome Are Crucial for Restriction of Neospora caninum Replication.

Neospora caninum poses as a considerable threat to animal health and generates significant economic impact in livestock production worldwide. Here, we have investigated the mechanism that underlies the participation of the inflammasome complex and Reactive Oxygen Species (ROS) in the regulation of immune responses during N. caninum infection. For that purpose, we used in vitro (bone marrow derived macrophages) and in vivo mouse models of infection. Our results show that NLRP3 and NLRC4 receptors, alongside with ASC and Caspase-1, are required for proper activation of the inflammasome during N. caninum infection. As expected, the engagement of these pathways is crucial for IL-1α, IL-1ß, and IL-18 production, as well as the induction of pyroptosis. Our results also show that N. caninum induces ROS production dependent of the inflammasome assembly, which in its turn also depends on MyD88/NF-κB-induced ROS to maintain its activation and, ultimately, lead to restriction of parasite replication.

Serological evidence of Toxoplasma gondii infection in Melanosuchus niger (Spix, 1825) and Caimam crocodilus (Linnaeus, 1758).

Toxoplasma gondii is a protozoan with worldwide prevalence, known to affect a large variety of warm-blooded hosts. However, its ability to induce long-lasting infections in cold-blooded animals remains unclear. The most likely source of infection is through consumption of meat containing tissue cysts or by ingestion of food or water contaminated with oocysts. The current global climate change trend and the progressive degradation of natural habitats are prone to alter the distribution of ectotherm populations over a short period of time, which may favor contact between these animals and the protozoan. In association, alligator meat is considered a delicacy in many regions and its consumption has been previously related to a diversity of foodborne diseases. In that sense, we proposed in this study to search for specific antibodies against T. gondii in serum samples of two common species of alligators from the Brazilian fauna (Melanosuchus niger and Caimam crocodilus). We obtained the serum samples from 84 alligators from the Araguaia region, which were tested by agglutination assays that do not require species-specific secondary antibodies (Modified Agglutination Test - MAT; Indirect Hemagglutination Assay - IHA). From the 84 samples tested, eight (9.5%) were positive by MAT. From those, seven (87.5% of MAT+, 8.3% of the total) were also positive by IHA, reassuring a probable exposure of these animals to the parasite. Direct parasite detection in muscle fragments of one serologically reactive alligator did not yield positive results. Our results provide serological evidence that Brazilian alligators may be exposed to T. gondii and further studies should be performed to elucidate whether alligators are natural hosts of this ubiquitous protozoan parasite.

Primeiro caso de COVID-19 em uma unidade de Cuidados Paliativos oncológicos: relato de experiência / First case of covid-19 in an oncological palliative care unit: experience report

Objetivo: Relatar a experiência da assistência de Enfermagem à primeira paciente em Cuidados Paliativos oncológicos com COVID-19, no Rio de Janeiro. Método: Trata-se de estudo descritivo do tipo relato de experiência acerca da assistência de Enfermagem à paciente com COVID-19 em instituição de referência. Resultados: Durante o levantamento de dados, constatou-se que a assistência de Enfermagem é fragmentada e sem sistematização em registros e prontuário, consistindo em: vigilância do estado geral da paciente, assistência ventilatória e risco de queda. Incluíram-se medidas para aliviar o medo frente aos sintomas físicos mais expressivos. O uso da tecnologia por videochamada foi o recurso utilizado para amenizar a ansiedade. Conclusão: A abordagem da equipe de enfermagem à paciente com doença avançada e com COVID-19 se torna peculiar pela rápida evolução desta doença, tornando a assistência de enfermagem múltipla, complexa, com cuidados biopsicossocioculturais. O rápido agravamento da doença, isolamento, ausência de cuidador/familiar e risco de contaminação da equipe frente à adequação do serviço de internação hospitalar no contexto da pandemia fizeram com que a assistência de enfermagem fosse mais específica e cuidadosa. Em meio ao caos, à mistura de sentimentos e ao medo, vivenciou-se a verdadeira essência do Cuidado Paliativo. (AU)

Objective: To report the experience of nursing care to the first patient in palliative care oncology with COVID-19, in Rio de Janeiro. Method: This is a descriptive study of an experience report about nursing care for patients with COVID-19 in a reference institution. Results: During data collection, it was found that nursing care is fragmented and without systematization in records and medical records, consisting of: surveillance of the general condition of the patient, ventilatory assistance and risk of falling. Measures to alleviate fear in the face of the most expressive physical symptoms were included. The use of technology by video call was the resource used to alleviate anxiety. Conclusion: The nursing team's approach to patients with advanced disease and with COVID-19 becomes peculiar due to the rapid evolution of this disease, making nursing care multiple, complex, with biopsychosociocultural care. The rapid worsening of the disease, isolation, absence of caregiver / family and risk of contamination of the team in view of the adequacy of the hospitalization service in the context of the pandemic made nursing care more specific and careful. In the midst of chaos, mixed feelings and fear, the true essence of Palliative Care was experienced. (AU)

Objetivo: informar la experiencia de la atención de enfermería al primer paciente en oncología de cuidados paliativos con COVID-19, en Río de Janeiro. Método: Este es un estudio descriptivo de un informe de experiencia sobre cuidados de enfermería para pacientes con COVID-19 en una institución de referencia. Resultados: Durante la recolección de datos, se encontró que la atención de enfermería está fragmentada y sin sistematización en los registros y registros médicos, que consiste en: vigilancia del estado general del paciente, asistencia respiratoria y riesgo de caídas. Se incluyeron medidas para aliviar el miedo frente a los síntomas físicos más expresivos. El uso de la tecnología por videollamada fue el recurso utilizado para aliviar la ansiedad. Conclusión: El enfoque del equipo de enfermería para pacientes con enfermedad avanzada y con COVID-19 se vuelve peculiar debido a la rápida evolución de esta enfermedad, lo que hace que la atención de enfermería sea múltiple, compleja y con atención biopsicosociocultural. El rápido empeoramiento de la enfermedad, el aislamiento, la ausencia del cuidador / familia y el riesgo de contaminación del equipo en vista de la idoneidad del servicio de hospitalización en el contexto de la pandemia hicieron que la atención de enfermería fuera más específica y cuidadosa. En medio del caos, sentimientos encontrados y miedo, se experimentó la verdadera esencia de los cuidados paliativos. (AU)

Corrigendum: Neospora Caninum Activates p38 MAPK as an Evasion Mechanism against Innate Immunity.

[This corrects the article DOI: 10.3389/fmicb.2016.01456.].

Randomized Controlled Trial of Oropharyngeal Colostrum Administration in Very-low-birth-weight Preterm Infants.

OBJECTIVE: The purpose of this study was to evaluate the effects of oropharyngeal colostrum administration in the incidence of late-onset clinical and proven sepsis and in concentrations of immunoglobulin A (IgA) in very-low-birth-weight (VLBW) infants. METHODS: We conducted a double-blinded, randomized, placebo-controlled trial and assigned 113 VLBW infants to receive 0.2 mL of maternal colostrum or sterile water (placebo) via oropharyngeal route every 2 hours for 48 hours, beginning in the first 48 to 72 hours of life. Neonates of both groups were fed breast milk from the first 3 days of life until a volume of at least 100 mL ·â€Škg ·â€Šday. IgA was measured in serum and urine before and after treatment. Clinical data during hospitalization were collected. RESULTS: We found no statistically significant differences between colostrum and placebo groups in the incidence of late-onset clinical sepsis (odds ratio 0.7602; CI 95% 0.3-1.6) and proven sepsis (odds ratio 0.7028; CI 95% 0.3-1.6). The measurement of IgA was similar in serum before (P value 0.87) and after treatment (P value 0.26 day 4 and 0.77 day 18). No differences were also observed in IgA in urine before (P value 0.8) and after treatment (P value 0.73 day 4 and 0.52). CONCLUSIONS: This study could not confirm the hypothesis that oropharyngeal administration of maternal colostrum to VLBW could reduce the incidence of late-onset sepsis and increase the levels of IgA. We believe that this finding can be justified by the practice of feeding VLBW infants exclusively with breast milk in the first days of life and reinforces the prior knowledge of the importance of early nutrition, especially, with human milk. It also suggests that oropharyngeal administration of colostrum should be reserved for neonates who cannot be fed in first few days of life.

Acetonic Fraction of Bidens pilosa Enriched for Maturase K Is Able to Control Cerebral Parasite Burden in Mice Experimentally Infected With Toxoplasma gondii.

Toxoplasma gondii infection can cause abortions or congenital infection for a vast number of domestic animals and humans, leading to economic loss in veterinary sciences, as well as severe consequences for immunocompromised patients. Bidens pilosa Linné has been used in ethnopharmacology for treatment of diseases, as malaria, diabetes and hepatitis, in addition to its use as antioxidant, antiallergic, anti-inflammatory, and antiviral. The components of this plant have never been studied before for treatment of toxoplasmosis, and the conventional drugs currently used to treat this disease have high degree of toxicity. Thus, the aim of this study was to evaluate the effect of B. pilosa against T. gondii, by analyzing a total extract of this plant in parallel with a fraction obtained by precipitation in acetone. Also, it was assessed if the acetonic fraction could present lectinic activity, followed by its identification by mass spectrometry. It was observed with the experimental models designed that both total extract and acetonic fraction of B. pilosa were able to control T. gondii infection by in vitro and in vivo experiments, in addition to their low toxicity to host cells. Both total extract and acetonic fraction of this plant display capacity to impair replication of T. gondii tachyzoites. Interesting, the B. pilosa acetonic fraction treatment for 10 days after infection decreases significantly the number of T. gondii brain cyst in comparison with controls. The protein isolated from B. pilosa acetonic fraction was characterized as a novel lectin identified as maturase K. Taken together, these findings open new perspectives to treat patients infected by T. gondii. Future studies will be necessary to investigate the precise mechanism underlying the control of T. gondii infection to impair the replication of this parasite in the host cells after treatment with B. pilosa maturase K.

Toll-Like Receptor 3-TRIF Pathway Activation by Neospora caninum RNA Enhances Infection Control in Mice.

Neospora caninum is a protozoan parasite closely related to Toxoplasma gondii and has been studied for causing neuromuscular disease in dogs and abortions in cattle. It is recognized as one of the main transmissible causes of reproductive failure in cattle and consequent economic losses to the sector. In that sense, this study aimed to evaluate the role of Toll-like receptor 3 (TLR3)-TRIF-dependent resistance against N. caninum infection in mice. We observed that TLR3-/- and TRIF-/- mice presented higher parasite burdens, increased inflammatory lesions, and reduced production of interleukin 12p40 (IL-12p40), tumor necrosis factor (TNF), gamma interferon (IFN-γ), and nitric oxide (NO). Unlike those of T. gondii, N. caninum tachyzoites and RNA recruited TLR3 to the parasitophorous vacuole (PV) and translocated interferon response factor 3 (IRF3) to the nucleus. We also observed that N. caninum upregulated the expression of TRIF in murine macrophages, which in turn upregulated IFN-α and IFN-ß in the presence of the parasite. Furthermore, TRIF-/- infected macrophages produced lower levels of IL-12p40, while exogenous IFN-α replacement was able to completely restore the production of this key cytokine. Our results show that the TLR3-TRIF signaling pathway enhances resistance against N. caninum infection in mice, since it improves Th1 immune responses that result in controlled parasitism and reduced tissue inflammation, which are hallmarks of the disease.

In vitro tracking of phospholipase A2 from snake venom conjugated with magic-sized quantum dots.

Phospholipases A2 represent a family of enzymes with important application in medicine. However, direct tracking is difficult due to the absence of a stable, effective and specific marker for these enzymes. Magic-sized quantum dots (MSQDs) are inorganic semiconducting nanocrystals with unique physical properties. They have the ability to conjugate to proteins, making them excellent markers for biological systems. In this work, we labelled phospholipase A2 from Bothrops alternatus snake venom with Cadmium selenide (CdSe)/cadmium sulphate (CdS) MSQDs-a biocompatible and luminescent probe-. Bioconjugation was confirmed using infrared spectra and fluorescence microscopy, which demonstrated that the CdSe/CdS MSQDs interact with phospholipase A2 without interfering with its activity. This probe may be an important tool for the elucidation of many biological mechanisms, because it allows the pathway of phospholipase A2 to be tracked from its entry through the plasma membrane until its incorporation into the nucleus of myoblasts.

BaltPLA2: A New Phospholipase A2 from Bothrops Alternatus Snake Venom with Antiplatelet Aggregation Activity.

BACKGROUND: In last decades, snake venoms have aroused great interest of the medicine due to the pathophysiological effects caused by their toxins. These include the phospholipases A2, low molecular weight proteins capable of causing haemorrhagic, myotoxic, inflammatory and neurotoxic effects after an ophidian accident. The present work describes the isolation and biochemical characterization of a new PLA2 isolated from the B. alternatus snake venom, which was named BaltPLA2. METHOD: The rapid and efficient purification of this toxin was performed using only two chromatography steps (anion exchange and hydrophobic chromatography). RESULTS: BaltPLA2 is an acidic protein (pI 4.4) with an apparent molecular mass of 17000 (SDSPAGE) and 14074.74 Da (MALDI TOF/TOF). Analysis of fragments ion by MS / MS showed the following internal amino acid sequence SGVIICGEGTPCEK, which did not exhibit homology with other PLA2 from the same venom. BaltPLA2 is a catalytically active, which displayed an anticoagulant action, inhibition of platelet aggregation induced by epinephrine (~ 80%) and ADP (24%). BaltPLA2 also was able to induce myonecrosis and the release of cytokines (IL-10, IL-12 and TNF- α) in macrophages culture. CONCLUSION: The results presented in this work greatly contribute to a better understanding of the mechanism of enzymatic and pharmacological actions of PLA2s from snake venoms and they may contribute to its application in medical research.

Antiparasitic effects induced by polyclonal IgY antibodies anti-phospholipase A2 from Bothrops pauloensis venom.

Activities of phospholipases (PLAs) have been linked to pathogenesis in various microorganisms, and implicated in cell invasion and so the interest in these enzymes as potential targets that could contribute to the control of parasite survival and proliferation. Chicken eggs immunized with BnSP-7, a Lys49 phospholipase A2 (PLA2) homologue from Bothrops pauloensis snake venom, represent an excellent source of polyclonal antibodies with potential inhibitory activity on parasite PLAs. Herein, we report the production, characterization and anti-parasitic effect of IgY antibodies from egg yolks of hens immunized with BnSP-7. Produced antibodies presented increasing avidity and affinity for antigenic toxin epitopes throughout immunization, attaining a plateau after 4weeks. Pooled egg yolks-purified anti-BnSP-7 IgY antibodies were able to specifically recognize different PLA2s from Bothrops pauloensis and Bothrops jararacussu venom. Antibodies also neutralized BnSP-7 cytotoxic activity in C2C12 cells. Also, the antibodies recognized targets in Leishmania (Leishmania) amazonensis and Toxoplasma gondii extracts by ELISA and immunofluorescence assays. Anti-BnSP-7 IgY antibodies were cytotoxic to T. gondii tachyzoite and L. (L.) amazonensis promastigotes, and were able to decrease proliferation of both parasites treated before infection. These data suggest that the anti-BnSP-7 IgY is an important tool for discovering new parasite targets and blocking parasitic effects.

Eutirucallin: A Lectin with Antitumor and Antimicrobial Properties.

Eutirucallin is a lectin isolated from the latex of Euphorbia tirucalli, a plant known for its medical properties. The present study explores various characteristics of Eutirucallin including stability, cytotoxicity against tumor cells, antimicrobial and antiparasitic activities. Eutirucallin was stable from 2 to 40 days at 4°C, maintained hemagglutinating activity within a restricted range, and showed optimal activity at pH 7.0-8.0. Eutirucallin presented antiproliferative activity for HeLa, PC3, MDA-MB-231, and MCF-7 tumor cells but was not cytotoxic for non-tumorigenic cells such as macrophages and fibroblasts. Eutirucallin inhibited the Ehrlich ascites carcinoma in vivo and it was also observed that Eutirucallin inhibited 62.5% of Escherichia coli growth. Also, Eutirucallin showed to be effective when tested directly against Toxoplasma gondii infection in vitro. Therefore, this study sheds perspectives for pharmacological applications of Eutirucallin.

Dectin-1 Compromises Innate Responses and Host Resistance against Neospora caninum Infection.

Neospora caninum is an intracellular protozoan parasite that has drawn increasing interest due to its association with worldwide repetitive bovine abortions, which cause billionaire losses to the meat and dairy industries annually. Innate immunity plays an important role in infection control, and N. caninum activates the production of inflammatory mediators through toll-like receptors, NOD-like receptors, and mitogen-activated protein kinase signaling pathways. Advances in the knowledge of initial host-parasite interactions are desirable for the design of control measures against the infection, obliterating its pathogenesis. In that sense, we here aimed to describe the role of the innate C-type lectin receptor Dectin-1 during the infection by N. caninum. With that intent, we observed that the absence of Dectin-1, observed in genetically depleted (Dectin-1-/-) mice or competitively inhibited by an inert agonist [laminarin (LAM)], rescued 50% of the mice infected with lethal doses of N. caninum. Dectin-1-/- and LAM-treated mice also presented a reduction in the parasite load during acute and chronic phases, associated with decreased inflammatory scores in the central nervous system. Among all the cell phenotypes that migrated to the initial site of infection, dendritic cells and macrophages gained subpopulations with high Dectin-1 surface expression. The impairment of the receptor in these cells led to a decreased parasite burden, as well as augmented production of IL-12p40. We also found that Dectin-1+ cells produced less reactive oxygen species (ROS) at the initial site of the infection, while mice deficient in NADPH oxidase isoform 2 (NOX2-/-) were not able to control parasite replication and produce IL-12p40, even upon LAM treatment. Interestingly, the absence of functional Dectin-1 did not alter the susceptibility of mice against closely related Toxoplasma gondii. In conclusion, the gathered data suggest that Dectin-1 is involved in the parasite-induced downmodulation of ROS, and other key molecules triggered for the control of N. caninum infection and are a promising target for future development of protocols intended for intervention against neosporosis.