RESUMO

Dengue fever is a mosquito-borne illness that infects 390 million people annually. Dengue outbreaks in Guatemala have been occurring more often and at increased rates since the first dengue outbreak in Guatemala in the 1970s. This study will examine environmental and socioeconomic factors associated with dengue in Guatemala at the municipality (county) level. Socioeconomic factors included population density, Mayan population, economic activity, and attending school. Environmental factors included average minimum annual temperature and annual precipitation. The relationship between environmental and socioeconomic variables and dengue fever incidence was initially evaluated through univariate zero-inflated negative binomial models, and then again through three zero-inflated multivariate negative binomial regression models. For all three models, elevation was considered a predictor of zero-inflation. In the combined model, there was a positive relationship between minimum temperature, economic activity and dengue fever incidence, and a negative relationship between population density, Mayan population and dengue fever. Predicted rates of dengue fever incidence and adjusted confidence intervals were calculated after increasing minimum yearly temperature by 1°C and 2°C. The three municipalities with the highest minimum yearly temperature (El Estor, Iztapa, and Panzós) and the municipality of Guatemala, all had an increase in the magnitude of the risk of dengue fever incidence following 1°C and 2°C increase in temperature. This research suggests that these socioeconomic and environmental factors are associated with risk of dengue in Guatemala. The predicted rates of dengue fever also highlight the potential effect that climate change in the form of increasing temperature can have on dengue in Guatemala.

Assuntos

RESUMO

Chagas disease (CD) is a parasitic infection caused by the parasite Trypanosoma cruzi. Reports of CD cases associated with oral transmission have increased, particularly in Colombia, Brazil, and Venezuela. In this investigation, parasitological, serological, and molecular tests were conducted on samples obtained from humans, mammal reservoirs, and hosts involved in the assessment of a suspected oral transmission outbreak in Cubara, Boyaca, Colombia. Seropositivity was observed in 60% (3 of 5) of index patients and 6.4% (5 of 78) of close contacts. Trypanosoma cruzi DNA was detected by quantitative polymerase chain reaction in 100% of index cases, 6.4% (5 of 78) of close contacts, 60% (6 of 10) of canines, and 100% (5 of 5) of opossums. In all index cases, the TcI lineage was identified, along with two cases of mixed infection (TcI/TcII-TcVI). Hemoculture revealed a flagellate presence in 80% of opossums, whereas all triatomine bugs tested negative. Our findings suggest a potential oral transmission route through contamination with opossum secretions.

Assuntos

RESUMO

Introducción: Las complicaciones asociadas al procedimiento de colocación de un dispositivo de oclusión septal se presentan en menos del 10 por ciento de los casos. La embolización requiere de cirugía cardíaca, por lo que se incrementa el riesgo de la mortalidad. Objetivo: Presentar el caso en una paciente con comunicación interventricular e hipertensión pulmonar severa que se le retiró el dispositivo de oclusión septal transcateterismo. Presentación de caso: Se presentó una mujer de 24 años de edad con comunicación interventricular, insuficiencia cardíaca (New York Heart Association) clase IV e hipertensión pulmonar tipo 2, que se programó para la colocación de dispositivo de oclusión septal, sin embargo, presentó fallo en la colocación del dispositivo y defecto residual de 7 mm, por lo que se realizó el retiro de este 48 h después sin presentar complicaciones. Conclusiones: Aunque el cierre transcateterismo de la comunicación interventricular es una alternativa segura y efectiva a la cirugía, no está exento de complicaciones. En caso de translocación del dispositivo de oclusión septal este debe ser retirado durante el mismo procedimiento, ya que el riesgo de embolización es elevado y en caso de presentarse, el riesgo de muerte se incrementa(AU)

Introduction: Complications associated with the placement procedure of a septal occlusion device occur in less than 10percent of cases. Embolization requires cardiac surgery, which increases the risk of mortality. Objective: To report the case of a patient with ventricular septal defect and severe pulmonary hypertension who had the transcatheter septal occlusion device removed. Case report: We report the case report of a 24-year-old woman with ventricular septal defect, heart failure (New York Heart Association) class IV and type 2 pulmonary hypertension. She was scheduled for placement of a septal occlusion device, however, the placement of the device failed and had a residual defect of 7 mm, so the placement was removed 48 hours later without complications. Conclusions: Although transcatheter closure of the ventricular septal defect is a safe and effective alternative to surgery, it is not free of complications. In case of translocation of the septal occlusion device, it must be removed during the same procedure, since the risk of embolization is high and if it occurs, the risk of death increases(AU)

Assuntos

RESUMO

Background: Dyslipidemia is a risk factor for the development of atherosclerosis and ischemic heart disease. Statins are safe drugs that are part of the routine treatment in patients with Acute Myocardial Infarction (AMI), however, rhabdomyolysis associated with severe myonecrosis due to statins can occur and associated complications such as acute kidney injury increase mortality. The main objective of this article is to report the case of a critically ill patient with AMI who presented severe statin-associated rhabdomyolysis documented with muscle biopsy. Description of the case: A 54-year-old man who presented with AMI, cardiogenic shock, and cardiorespiratory arrest requiring cardiopulmonary resuscitation, fibrinolysis, and successful salvage coronary angiography. However, he presented severe rhabdomyolysis associated with atorvastatin that required suspension of the drug and multi-organ support in a Coronary Care Unit. Conclusions: The prevalence of statin-associated rhabdomyolysis is low, however, the late elevation of CPK above 10 times its upper normal value in those patients with successful percutaneous coronary angiography should promptly draw attention, generate a diagnostic approach towards non-traumatic acquired causes of rhabdomyolysis and assess the suspension of statins.

Introducción: la dislipidemia es un factor de riesgo para el desarrollo de ateroesclerosis y cardiopatía isquémica. Las estatinas son fármacos seguros que forman parte del tratamiento de rutina en el paciente con infarto agudo de miocardio (IAM). Sin embargo, la rabdomiólisis asociada a mionecrosis severa por estatinas puede presentarse y las complicaciones asociadas como la lesión renal aguda incrementan la mortalidad. El objetivo principal de este artículo es reportar el caso de un paciente críticamente enfermo con IAM que presentó rabdomiólisis severa asociada a estatinas documentada con biopsia muscular. Caso clínico: hombre de 54 años que presentó IAM, choque cardiogénico y paro cardiorrespiratorio, que ameritó reanimación cardiopulmonar, fibrinólisis y angiografía coronaria de rescate exitosa. Sin embargo, presentó rabdomiólisis severa asociada a atorvastatina que requirió de suspensión del fármaco y soporte multiorgánico en una unidad de cuidados coronarios. Conclusiones: la prevalencia de la rabdomiólisis asociada a estatinas es baja, sin embargo, la elevación tardía de la CPK por arriba de 10 veces su valor superior normal en aquellos pacientes con angiografía coronaria percutánea exitosa debe llamar la atención, generar un abordaje diagnóstico hacia causas adquiridas no traumáticas de rabdomiólisis y valorar la suspensión de estatinas.

Assuntos

RESUMO

PURPOSE: The present consensus statement was developed by the GINECOR working group on behalf of the Spanish Society of Radiation Oncology (SEOR). Given the lack of prospective data on the management of vulvar carcinoma, this document provides an up-to-date review of radiotherapy treatment in vulvar cancer and a series of consensus-based recommendations from a group of experts. METHODS: A two-round, online modified Delphi study was conducted to reach consensus treatment recommendations in three clinical settings: 1) adjuvant treatment, 2) locally-advanced vulvar cancer (LAVC), and 3) recurrent disease. After the first round, we comprehensively reviewed the available medical literature from peer-reviewed journals to assess and define the evidence-based treatment options. In the second round, participants were asked to indicate their level of agreement with the preliminary recommendations according to the GRADE (Grade of Recommendation, Assessment, Development, and Evaluation) criteria, as follows: strongly agree; agree; neither agree nor disagree; disagree; strongly disagree. RESULTS: The main recommendations were as follows: 1) following surgical resection, adjuvant radiotherapy is recommended with the presence of adverse risk factors (primarily positive margins and lymph node involvement); 2) radiotherapy (with or without chemotherapy) should be considered in LAVC; and 3) in recurrent disease, radiotherapy should be individualised on a case-by-case basis. A high level of agreement over 80% was reached. CONCLUSIONS: In the absence of robust clinical data, these final recommendations may help to select the optimal radiotherapy approach for this relatively rare cancer.

Assuntos

RESUMO

PURPOSE: The present consensus statement was developed by the GINECOR working group on behalf of the Spanish Society of Radiation Oncology (SEOR). This document provides an up-to-date review of the technical aspects in radiation treatment of vulvar cancer. METHODS: A two-round modified Delphi study was conducted to reach consensus on the appropriateness of technical aspects of external beam radiotherapy and brachytherapy. Three clinical scenarios were proposed: adjuvant treatment of vulvar cancer, radiation treatment of locally advanced vulvar carcinoma and locoregional recurrences. After the first round, an extensive analysis of current medical literature from peer-reviewed journal was performed to define evidence-based treatment options. In the second round, participants were asked to indicate their level of agreement with the preliminary recommendations according to the GRADE (Grade of Recommendation, Assessment, Development, and Evaluation) criteria, as follows: strongly agree; agree; neither agree nor disagree; disagree and strongly disagree. RESULTS: The main recommendations on external beam radiotherapy and brachytherapy, both in adjuvant setting and local advanced disease are summarized. Recommendations include treatment technique, treatment volume, and doses in target and organs at-risk. Taking into consideration the different clinical scenarios of recurrent disease, the radiation treatment should be individualized. CONCLUSIONS: In the absence of robust clinical data, these recommendations may help to select the optimal radiotherapy approach for this relatively rare cancer.

Assuntos

RESUMO

Spa tourism has undergone important changes in recent decades, actively embracing wellness and wellbeing. However, this transition is taking place in different ways in Europe, and this has led to varying perceptions of thermalism that have little to do with its original conception. The main aim of this study was to analyse current perceptions of spa tourism amongst university students, so as to identify profiles and compare the differences between two study cases: Granada (Spain) and Aachen (Germany). For this purpose, we applied a methodology that combines artificial intelligence techniques with questionnaires containing both quantitative and qualitative variables. This enabled us to identify and characterize a series of profiles, so as to acquire detailed knowledge of the perceptions of these students regarding spa tourism in Granada and Aachen. On the basis of the results, the interviewees were grouped together into seven profiles from which we deduced that young Germans from Aachen visit spas more frequently and have a more realistic perception of the thermal sector than young Spanish people from Granada. This situation could limit present and future demand for spas in southern Spain. With this in mind, in this paper we present an updated assessment of the demand for spas amongst university students, in order to design effective geomarketing strategies in two cities with long spa traditions.

Assuntos

RESUMO

The Peruvian sea is one of the most productive ecosystems in the world. Phytoplankton production provides food for fish, mammals, mollusks and birds. This trophic network is affected by the presence of toxic phytoplankton species. In July 2017, samples of phytoplankton were obtained from Paracas Bay, an important zone for scallop (Argopecten purpuratus) aquaculture in Peru. Morphological analysis revealed the presence of the genus Pseudo-nitzschia, which was isolated and cultivated in laboratory conditions. Subsequently, the monoclonal cultures were observed by scanning electron microscopy (SEM), and identified as P. multistriata, based on both the morphological characteristics, and internal transcribed spacers region (ITS2) sequence phylogenetic analysis. Toxin analysis using liquid chromatography (LC) with high-resolution mass spectrometry (HRMS) revealed the presence of domoic acid (DA) with an estimated amount of 0.004 to 0.010 pg cell-1. This is the first report of DA from the coastal waters of Peru and its detection in P. multistriata indicates that it is a potential risk. Based on our results, routine monitoring of this genus should be considered in order to ensure public health.

Assuntos

RESUMO

Dengue virus serotypes 1, 2, 3, and 4 are transmitted by Aedes aegypti and Aedes albopictus mosquitoes, which cause illness in an estimated 100 million annually. Although dengue viruses are endemic throughout El Salvador, very little is known about their ecology and epidemiology. The principal methods to prevent and reduce dengue cases are through vector control and by adoption of a vaccine. In addition, understanding the environmental and socioeconomic factors associated with dengue could contribute to case reduction by targeting prevention efforts in dengue hotspots. This study investigated environmental and socioeconomic factors associated with dengue cases in El Salvador. Dengue cases were obtained from 2011 to 2013 for 262 municipalities. The mean incidence was determined for each municipality for the 3 year period. Negative binomial regression models evaluated the relationship between dengue cases and the environmental factors elevation, forest coverage, mean annual temperature, and cumulative precipitation. Twelve socioeconomic and infrastructure variables and their relationship with dengue were also investigated by using negative binomial regression. A total of 29,764 confirmed dengue cases were reported. The mean dengue incidence for 2011-2013 was 135/100,000. The highest number of dengue cases occurred in San Salvador and surrounding municipalities, as well as in two additional cities, Santa Ana and San Miguel; the highest incidence of dengue cases (per 100,000) occurred in cities in the west and at the center of the country. Significant environmental variables associated with dengue included temperature, precipitation, and non-forested area. The socioeconomic variables poverty rate, illiteracy rate, and school attendance, and the infrastructure variables percent of homes with sanitary service, municipal trash service, electricity, and cement brick flooring, as well as population density, were also significant predictors of dengue. Understanding these environmental and socioeconomic factors and their relationship with dengue will help design and implement timely prevention strategies and vector control to reduce dengue in El Salvador.

Assuntos

RESUMO

Dinophysis acuta and D. acuminata are associated with lipophilic toxins in Southern Chile. Blooms of the two species coincided during summer 2019 in a highly stratified fjord system (Puyuhuapi, Chilean Patagonia). High vertical resolution measurements of physical parameters were carried out during 48 h sampling to i) explore physiological status (e.g., division rates, toxin content) and ii) illustrate the fine scale distribution of D. acuta and D. acuminata populations with a focus on water column structure and co-occurring plastid-bearing ciliates. The species-specific resources and regulators defining the realized niches (sensu Hutchinson) of the two species were identified. Differences in vertical distribution, daily vertical migration and in situ division rates (with record values, 0.76 d-1, in D. acuta), in response to the environmental conditions and potential prey availability, revealed their niche differences. The Outlying Mean Index (OMI) analysis showed that the realized niche of D. acuta (cell maximum 7 × 103 cells L-1 within the pycnocline) was characterized by sub-surface estuarine waters (salinity 23 - 25), lower values of turbulence and PAR, and a narrow niche breath. In contrast, the realized niche of D. acuminata (cell maximum 6.8 × 103 cells L-1 just above the pycnocline) was characterized by fresher (salinity 17 - 20) outflowing surface waters, with higher turbulence and light intensity and a wider niche breadth. Results from OMI and PERMANOVA analyses of co-occurring microplanktonic ciliates were compatible with the hypothesis of species such as those from genera Pseudotontonia and Strombidium constituting an alternative ciliate prey to Mesodinium. The D. acuta cell maximum was associated with DSP (OA and DTX-1) toxins and pectenotoxins; that of D. acuminata only with pectenotoxins. Results presented here contribute to a better understanding of the environmental drivers of species-specific blooms of Dinophysis and management of their distinct effects in Southern Chile.

Assuntos

RESUMO

The immune system plays a key role in the protective response against oral cancer; however, the tumor microenvironment (TME) impairs this anti-cancer response by modulating T helper (Th) responses and promoting an anti-inflammatory environment. Regulatory T cells (Tregs) and Th2 effector cells (Teff) are associated with poor prognosis in oral squamous cell carcinoma (OSCC). However, the main immunomodulatory mechanisms associated with the enrichment of these subsets in OSCC remain unknown. We characterized Th-like lineages in Tregs and Teff and evaluated immunomodulatory changes induced by the TME in OSCC. Our phenotypic data revealed a higher distribution of tumour-infiltrating CCR8+ and Th2-like Treg in OSCC compared with non-malignant samples, whereas the percentages of Th1 cells were reduced in cancer. We then analyzed the direct effect of the TME by exposing T cell subsets to cancer secretomes and observed the OSCC secretome induced CCR8 expression and reduced cytokine production from both subsets. Transcriptomic analysis showed that the co-culture with OSCC secretome induced several gene changes associated with the vitamin D (VitD) signaling pathway in T cells. In addition, proteomic analysis identified the presence of several proteins associated with prostaglandin E2 (PGE2) production by rapid membrane VitD signaling and a reduced presence of the VitD binding protein. Thus, we analyzed the effect of VitD and PGE2 and observed that VitD promotes a regulatory Th2-like response with CCR8 expression whilst PGE2 also modulated CCR8 but inhibited cytokine production in combination with VitD. Finally, we evaluated the presence of CCR8 ligand in OSCC and observed increased chemokine CCL18, which was also able to upregulate CCR8 in activated Th cells. Overall, our data showed the immunomodulatory changes induced by the TME involving CCR8 expression and regulatory Th2 phenotypes, which are associated with PGE2 mediated VitD signaling pathway and CCL18 expression in OSCC.

Assuntos

RESUMO

RESUMEN La neurocisticercosis es una infección del sistema nervioso central provocada por la ingestión accidental de huevos de Taenia Solium, constituyendo la parasitosis más frecuente del propio sistema. Es un problema común en muchos países latinoamericanos, asiáticos y africanos; en áreas endémicas, es considerada la principal etiología de las epilepsias de inicio tardío. Se presenta el caso de un paciente de 39 años de edad, de sexo masculino, con historia de alteraciones del comportamiento y varias crisis convulsivas desde hacía un año atrás. Por este motivo fue trasladado al Hospital Militar Principal de Luanda e ingresado en el Servicio de Psiquiatría con diagnóstico presuntivo de neurosis histérica. Al mes de su egreso fue remitido nuevamente esta vez en el Servicio de Neurología del propio hospital. Se le realizó examen físico, se le indicaron complementarios y se le realizó rayos X de tórax y tomografía que mostraron imágenes sugestivas de neurocisticercosis activa. Se le indicó tratamiento farmacológico y fisioterapia. Lugo de ochenta días el paciente fue egresado, consciente, orientado, asintomático. El objetivo de la presentación es llamar la atención a especialistas que cumplen colaboración en diferentes partes del mundo al ser una enfermedad extremadamente rara en Cuba y a la que se deben enfrentar con cierta frecuencia en otras latitudes.

ABSTRACT Neurocysticercosis is an infection of the central nervous system caused by the accidental ingestion of eggs of Taenia Solium, constituting the most frequent parasitosis of the system itself. It is a common problem in many Latin American, Asian and African countries; in endemic areas, it is considered the main etiology of late-onset epilepsies. The case of a 39-year-old male patient with a history of behavioral disorders and several seizures for a year is presented. For this reason he was transferred to the Main Military Hospital of Luanda and admitted to the Psychiatry Service with a presumptive diagnosis of hysterical neurosis. A month after his discharge, he was referred again this time to the Neurology Service of the hospital itself. A physical examination was performed, supplementary tests were indicated, and a chest X-ray and tomography were performed, which showed images suggestive of active neurocysticercosis. Pharmacological treatment and physiotherapy were indicated. After eighty days, the patient was discharged, conscious, oriented, and asymptomatic. The objective of the presentation is to draw the attention of specialists who collaborate in different parts of the world as it is an extremely rare disease in Cuba and which they must face with certain frequency in other latitudes.

RESUMO

Dinophysis acuta produces diarrhetic shellfish poisoning (DSP) toxins and pectenotoxins (PTX). It blooms in thermally-stratified shelf waters in late summer in temperate to cold temperate latitudes. Despite its major contribution to shellfish harvesting bans, little effort has been devoted to study its population dynamics in Chilean Patagonia. In 2017-2018, mesoscale distribution of harmful algal species (75 monitoring stations) revealed the initiation (late spring) and seasonal growth of a dense D. acuta population in the Aysén region, with maximal values at Puyuhuapi Fjord (PF). Vertical phytoplankton distribution and fine-resolution measurements of physical parameters along a 25-km transect in February 16th identified a 15-km (horizontal extension) subsurface thin layer of D. acuta from 4 to 8 m depth. This layer, disrupted at the confluence of PF with the Magdalena Sound, peaked at the top of the pycnocline (6 m, 15.9 °C, 23.4 psu) where static stability was maximal. By February 22nd, it deepened (8 m, 15.5 °C; 23.62 psu) following the excursions of the pycnocline and reached the highest density ever recorded (664 × 103 cells L-1) for this species. Dinophysis acuta was the dominant Dinophysis species in all microplankton net-tows/bottle samples; they all contained DSP toxins (OA, DTX-1) and PTX-2. Modeled flushing rates showed that Puyuhuapi, the only fjord in the area with 2 connections with the open sea, had the highest water residence time. Long term climate variability in the Southern hemisphere showed the effects of a Southern Annular Mode (SAM) in positive mode (+1.1 hPa) overwhelming a moderate La Niña. These effects included positive spring precipitation anomalies with enhanced salinity gradients and summer drought with positive anomalies in air (+1 °C) and sea surface (+2 °C) temperature. Locally, persistent thermal stratification in PF seemed to provide an optimal physical habitat for initiation and bloom development of D. acuta. Thus, in summer 2018, a favourable combination of meteorological and hydrographic processes of multiple scales created conditions that promoted the development of a widespread bloom of D. acuta with its epicentre at the head of Puyuhuapi fjord.

Assuntos

RESUMO

The removal of highly concentrated pollutants, presented in a wastewater mixture from industrial tannery effluents by electrocoagulation, was examined. All experiments were carried out in a rotating cylinder electrode reactor with six aluminum anodes and two sedimentation tanks. The influence of the applied current density and rotational speed on the removal efficiency of an electrocoagulation reactor was studied. Chemical oxygen demand was diminished at 70%, while total suspended solids, chromium (III) and turbidity were almost eliminated (>90%) with 6 mA cm-2 of the applied current density. Additionally, a homogeneous cathodic deposit was obtained at the end of each test. Those cathodic deposits and flocs were analyzed by SEM-EDS. Calculations of the cell energy consumption and the produced aluminum cost were estimated for 6 mA cm-2 and 100 rpm, obtaining 1.98 kWh m-3 and $0.7 USD m-3, respectively.

Assuntos

RESUMO

Domoic acid (DA), the main toxin responsible for Amnesic Shellfish Poisoning, frequently affects the marine resources of Chile and other countries across the South Pacific, thus becoming a risk for human health. One of the affected resources is the scallop Argopecten purpuratus. Even though this species has a high commercial importance in Northern Chile and Peru, the characteristics of its DA depuration are not known. In this work, the DA depuration was studied by means of two experiments: one in controlled (laboratory) and another in natural conditions. All organs of A. purpuratus depurated the toxin very quickly in both experiments. In some organs, an increase or a very small decrease of toxin was detected in the early depuration steps. Several models were used to describe this kinetics. The one that included toxin transfer between organs and independent depuration from each organ was the model that best fit the data. It seems, therefore, that the DA in this species is quickly transferred from the digestive gland to all other organs, which release it into the environment. Physiological differences in the two experiments have been shown to have some effect on the depuration from each organ but the actual reasons are still unknown.

Assuntos

RESUMO

Brucella abortus is a pathogen that survives in macrophages. Several virulence factors participate in this process, including the open reading frame (ORF) BAB1_0270 codifying for a zinc-dependent metalloproteinase (ZnMP). Here, its contribution in the intracellular adaptation of B. abortus was analyzed by infecting RAW264.7 macrophages with the mutant B. abortus Δ270 strain. Results showed that this ZnMP did not participated in either the adherence or the initial intracellular traffic of B. abortus in macrophages. Nevertheless, its deletion significantly increased the co-localization of B. abortus Δ270 with phagolysosomal cathepsin D and reduced its co-localization with calnexin present in endoplasmic reticulum (RE)-derived vesicles. Although B. abortus Δ270 showed an upregulated expression of genes involved in virulence (vjbR, hutC, bvrR, virB1), it was insufficient to reach a successful intracellular replication within macrophages. Furthermore, its attenuation favored in macrophages infected the production of high levels of cytokines (TNF-α and IL-6) and co-stimulatory proteins (CD80 and CD86), signals required in T cell activation. Finally, its deletion significantly reduced the ability of B. abortus Δ270 to adapt, grow and express several virulence factors under acidic conditions. Based on these results, and considering that this ZnMP has homology with ImmA/IrrE proteases, we discuss its role in the virulence of this pathogen, concluding that ZnMP is required in the intracellular adaptation of B. abortus 2308 during the infection of macrophages.

RESUMO

Brucella abortus is a facultative intracellular pathogen that causes a zoonosis called brucellosis. This disease leads to abortion and infertility in cattle, and diverse complications in humans. B. abortus is a successful intracellular bacterium that has developed the ability to evade the host's immune system and it replicates in professional and non-professional phagocytic cells, persisting in the different tissues, and organs of its hosts. It has been described that Brucella expresses a polar flagellum under certain conditions, but its function is still unknown. In this study we evaluated the role of the FlgJ, a protein, presumably a peptidoglycan hydrolase involved in flagellum formation and in the virulence of B. abortus strain 2308. B. abortus 2308 ΔflgJ mutant and complemented strains were constructed to study the function of the FlgJ protein in the context of the virulence of this pathogen in in vitro and in vivo assays. The results showed that the elimination of the flgJ gene delays the growth rate of B. abortus in culture, reduces its intracellular survival capacity in professional and non-professional phagocytic cells, rendering it unable to escape from the endocytic route and not reaching the endoplasmic reticulum. It also negatively affects their persistence in BALB/c mice. Functionally, the B. abortus 2308 flgJ gene restored motility to an E. coli flgJ mutant gene. Furthermore, it was discovered that the production of FlgJ protein is associated with the bacterial adherence by B. abortus. Therefore, although the specific function of the polar flagellum for Brucella is unknown, the data indicates that the flagellar flgJ gene and its product are required for full virulence of B. abortus 2308, since its deletion significantly reduces the fitness of this pathogen in vitro and in vivo.

Assuntos

RESUMO

Phalacroma rotundatum is a rare cosmopolitan heterotrophic dinoflagellate. This species, included in the IOC-UNESCO Taxonomic Reference List of Harmful Microalgae, may be a diarrhetic shellfish poisoning (DSP) toxin vector, but little is known about its ecophysiology and behavior. A vertical net haul collected during the austral summer of 2018 in Reloncaví Sound (Chilean Patagonia) revealed an unusually abundant population of P. rotundatum and prompted intensive 24 h sampling on 16-17 January to study the cell cycle and feeding behavior of this species. Hydrographic measurements from a buoy revealed the local characteristic estuarine circulation, with a brackish surface layer (salinity 26-28) separated from saltier, colder bottom waters by a pycnocline at a depth modulated by the tidal regime. A high proportion of P. rotundatum cells were packed with digestive vacuoles (peak of 70% at 14:00), and phased cell division (µ = 0.46 d-1) occurred 3 h after sunrise. The division time (TD) was 2 h. This is the first cell cycle study of P. rotundatum. The results here disagree with those of previous field studies that considered asynchronous division in some Dinophysis species to be related to heterotrophic feeding. They also question the very specific prey requirements, Tiarina fusus, reported for P. rotundatum in northern Europe.

RESUMO

In late February 2016, a harmful algal bloom (HAB) of Alexandrium catenella was detected in southern Chiloé, leading to the banning of shellfish harvesting in an extended geographical area (~500 km). On April 24, 2016, this bloom produced a massive beaching (an accumulation on the beach surface of dead or impaired organisms which were drifted ashore) of surf clams Mesodesma donacium in Cucao Bay, Chiloé. To determine the effect of paralytic shellfish poisoning (PSP) toxins in M. donacium, samples were taken from Cucao during the third massive beaching detected on May 3, 2016. Whole tissue toxicity evidence a high interindividual variability with values which ranged from 1008 to 8763 µg STX eq 100 g-1 and with a toxin profile dominated by GTX3, GTX1, GTX2, GTX4, and neoSTX. Individuals were dissected into digestive gland (DG), foot (FT), adductor muscle (MU), and other body fractions (OBF), and histopathological and toxin analyses were carried out on the obtained fractions. Some pathological conditions were observed in gill and digestive gland of 40⁻50% of the individuals that correspond to hemocyte aggregation and haemocytic infiltration, respectively. The most toxic tissue was DG (2221 µg STX eq 100 g-1), followed by OBF (710 µg STX eq 100 g-1), FT (297 µg STX eq 100 g-1), and MU (314 µg STX eq 100 g-1). The observed surf clam mortality seems to have been mainly due to the desiccation caused by the incapability of the clams to burrow. Considering the available information of the monitoring program and taking into account that this episode was the first detected along the open coast of the Pacific Ocean in southern Chiloé, it is very likely that the M. donacium population from Cucao Bay has not had a recurrent exposition to A. catenella and, consequently, that it has not been subjected to high selective pressure for PSP resistance. However, more research is needed to determine the effects of PSP toxins on behavioral and physiological responses, nerve sensitivity, and genetic/molecular basis for the resistance or sensitivity of M. donacium.

Assuntos