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Introduction: Severe acute respiratory syndrome virus 2 (SARS-CoV-2) has caused over million deaths worldwide, with more than 61,000 deaths in Chile. The Chilean government has implemented a vaccination program against SARS-CoV-2, with over 17.7 million people receiving a complete vaccination scheme. The final target is 18 million individuals. The most common vaccines used in Chile are CoronaVac (Sinovac) and BNT162b2 (Pfizer-Biotech). Given the global need for vaccine boosters to combat the impact of emerging virus variants, studying the immune response to SARS-CoV-2 is crucial. In this study, we characterize the humoral immune response in inoculated volunteers from Chile who received vaccination schemes consisting of two doses of CoronaVac [CoronaVac (2x)], two doses of CoronaVac plus one dose of BNT162b2 [CoronaVac (2x) + BNT162b2 (1x)], and three doses of BNT162b2 [BNT162b2 (3x)]. Methods: We recruited 469 participants from Clínica Dávila in Santiago and the Health Center Víctor Manuel Fernández in the city of Concepción, Chile. Additionally, we included participants who had recovered from COVID-19 but were not vaccinated (RCN). We analyzed antibodies, including anti-N, anti-S1-RBD, and neutralizing antibodies against SARS-CoV-2. Results: We found that antibodies against the SARS-CoV-2 nucleoprotein were significantly higher in the CoronaVac (2x) and RCN groups compared to the CoronaVac (2x) + BNT162b2 (1x) or BNT162b2 (3x) groups. However, the CoronaVac (2x) + BNT162b2 (1x) and BNT162b2 (3x) groups exhibited a higher concentration of S1-RBD antibodies than the CoronaVac (2x) group and RCN group. There were no significant differences in S1-RBD antibody titers between the CoronaVac (2x) + BNT162b2 (1x) and BNT162b2 (3x) groups. Finally, the group immunized with BNT162b2 (3x) had higher levels of neutralizing antibodies compared to the RCN group, as well as the CoronaVac (2x) and CoronaVac (2x) + BNT162b2 (1x) groups. Discussion: These findings suggest that vaccination induces the secretion of antibodies against SARS-CoV-2, and a booster dose of BNT162b2 is necessary to generate a protective immune response. In the current state of the pandemic, these data support the Ministry of Health of the Government of Chile's decision to promote heterologous vaccination as they indicate that a significant portion of the Chilean population has neutralizing antibodies against SARS-CoV-2.
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COVID-19 , Vacinas , Humanos , Imunidade Humoral , SARS-CoV-2 , Vacina BNT162 , Chile , COVID-19/prevenção & controle , Vacinação , Anticorpos NeutralizantesRESUMO
A central problem in developmental and synthetic biology is understanding the mechanisms by which cells in a tissue or a Petri dish process external cues and transform such information into a coherent response, e.g., a terminal differentiation state. It was long believed that this type of positional information could be entirely attributed to a gradient of concentration of a specific signaling molecule (i.e., a morphogen). However, advances in experimental methodologies and computer modeling have demonstrated the crucial role of the dynamics of a cell's gene regulatory network (GRN) in decoding the information carried by the morphogen, which is eventually translated into a spatial pattern. This morphogen interpretation mechanism has gained much attention in systems biology as a tractable system to investigate the emergent properties of complex genotype-phenotype maps. In this study, we apply a Markov chain Monte Carlo (MCMC)-like algorithm to probe the design space of three-node GRNs with the ability to generate a band-like expression pattern (target phenotype) in the middle of an arrangement of 30 cells, which resemble a simple (1-D) morphogenetic field in a developing embryo. Unlike most modeling studies published so far, here we explore the space of GRN topologies with nodes having the potential to perceive the same input signal differently. This allows for a lot more flexibility during the search space process, and thus enables us to identify a larger set of potentially interesting and realizable morphogen interpretation mechanisms. Out of 2061 GRNs selected using the search space algorithm, we found 714 classes of network topologies that could correctly interpret the morphogen. Notably, the main network motif that generated the target phenotype in response to the input signal was the type 3 Incoherent Feed-Forward Loop (I3-FFL), which agrees with previous theoretical expectations and experimental observations. Particularly, compared to a previously reported pattern forming GRN topologies, we have uncovered a great variety of novel network designs, some of which might be worth inquiring through synthetic biology methodologies to test for the ability of network design with minimal regulatory complexity to interpret a developmental cue robustly.
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Redes Reguladoras de Genes , Biologia de Sistemas , Expressão Gênica , Redes Reguladoras de Genes/genética , Transdução de Sinais/genética , Biologia SintéticaRESUMO
ABSTRACT The understanding of the relationships between the planktonic communities in a reservoir allows us to infer possible changes in the redistribution of matter and energy flows in these systems. This work proposes a dynamic model for the trophic network of the Riogrande II tropical reservoir, which integrates the planktonic trophic chains of detritus and grazing, limiting the prey-predator interactions by introducing the prey meeting factor (pmf). We built a dynamic model of mass balance supported by an extensive bibliographic search. The limitations of consumers and resources were represented simultaneously by means of the pmf. The data used to validate the model were compiled from previous investigations carried out in this reservoir from 2010 to 2013. The values of pmf that we found in each simulation suggest that the top predator can access its main prey in certain concentrations of total phosphorus, with a probability of encounter ranging from 9.3 % to 17.7 %. Our simulations indicate that most of the primary production is poorly used by the primary consumers in the photic zone, however, it enters in the flows of the detrital chain and supports the production of zooplankton almost entirely. According to this finding, the biomass densities obtained in the previous studies can be better explained by the causal relationships assumed in this model.
RESUMEN Entender las relaciones entre las comunidades planctónicas en un embalse nos permite inferir posibles cambios en la redistribución de los flujos de materia y energía en este sistema. Este trabajo propone un modelo dinámico para representar la red trófica del embalse tropical Riogrande II, donde se integran las cadenas tróficas de pastoreo y detritus y se limitan las interacciones entre predadores, presas y recursos al introducir un factor limitante de encuentro con la presa (pmf). El modelo dinámico se enfoca en el balance de masas sustentado en una amplia búsqueda bibliográfica. Los datos usados para validar el modelo se colectaron de datos previamente reportados para el embalse durante los años 2010 y 2013. Los valores de pmf obtenidos en cada simulación, sugieren que el predador dominante puede acceder a su presa principal a ciertas concentraciones de fósforo total, con una probabilidad de encuentro que va desde 9,3 % hasta 17,7 %. Nuestros resultados indican que la mayor parte de la producción primaria es poco aprovechada por los consumidores en la zona fótica, sin embargo, ingresa en el flujo de la cadena detrítica de manera que soporta la producción de zooplancton casi por completo. Las relaciones causales asumidas en este modelo explican en gran medida las densidades de biomasa reportadas en estudios previos.
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Cryo-electron microscopy (cryo-EM) has revolutionized structural biology by providing 3D density maps of biomolecules at near-atomic resolution. However, map validation is still an open issue. Despite several efforts from the community, it is possible to overfit 3D maps to noisy data. Here, we develop a novel methodology that uses a small independent particle set (not used during the 3D refinement) to validate the maps. The main idea is to monitor how the map probability evolves over the control set during the 3D refinement. The method is complementary to the gold-standard procedure, which generates two reconstructions at each iteration. We low-pass filter the two reconstructions for different frequency cutoffs, and we calculate the probability of each filtered map given the control set. For high-quality maps, the probability should increase as a function of the frequency cutoff and the refinement iteration. We also compute the similarity between the densities of probability distributions of the two reconstructions. As higher frequencies are included, the distributions become more dissimilar. We optimized the BioEM package to perform these calculations, and tested it over systems ranging from quality data to pure noise. Our results show that with our methodology, it possible to discriminate datasets that are constructed from noise particles. We conclude that validation against a control particle set provides a powerful tool to assess the quality of cryo-EM maps.
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Recently, a salivary gland transcriptome study demonstrated that the transcripts of a putative cystatin gene (SeqID AAEL013287; Aacystatins) from Aedes aegypti were increased in DENV2-infected mosquitoes and that silencing of the Aacystatin gene resulted in an increase in DENV titres. In this work, Aacystatin was biochemically characterized; the purified recombinant inhibitor was able to inhibit typical cysteine proteases with a Ki in the nM range. Pulldown assays using Aag2 cell extracts identified a cathepsin L-like peptidase (AaCatL) as a possible target of Aacystatin. Purified recombinant AaCatL had an optimal pH of 5.0 and displayed a preference for Leu, Val and Phe residues at P2, which is common for other cathepsin L-like peptidases. Transcription analysis of Aacystatin and AaCatL in the salivary glands and midgut of DENV2-infected mosquitoes revealed a negative correlation between DENV2 titres and levels of the inhibitor and peptidase, suggesting their involvement in DENV2-mosquito interactions. Considering that apoptosis may play an important role during viral infections, the possible involvement of Aacystatin in staurosporine-induced apoptosis in Aag2 cells was investigated; the results showed higher expression of the inhibitor in treated cells; moreover, pre incubation with rAacystatin was able to increase Aag2 cell viability.
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Aedes , Catepsina L , Cistatinas , Vírus da Dengue/metabolismo , Proteínas de Insetos , Aedes/enzimologia , Aedes/genética , Aedes/virologia , Animais , Catepsina L/química , Catepsina L/genética , Catepsina L/metabolismo , Linhagem Celular , Cistatinas/química , Cistatinas/genética , Cistatinas/metabolismo , Proteínas de Insetos/química , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismoRESUMO
Introducción: la infección por Helicobacter pylori es la enfermedad bacteriana crónica más prevalente en el ser humano. Objetivo: determinar la prevalencia general de esta infección. Método: se realizó un estudio descriptivo, longitudinal y prospectivo en 138 pacientes dispépticos. Para la identificación de la bacteria se emplearon tres métodos diagnósticos: serológico, histológico y cultivo. Resultados: la prevalencia del Helicobacter pylori fue de un 83,3 por ciento. La serología tuvo sensibilidad de 98 por ciento y especificidad de 34 por ciento. La histología fue de 83 por ciento y 25 por ciento, respectivamente. La infección predominó en el sexo femenino (44,2 por ciento) y en el grupo de edad de 31-40 años (18,8 por ciento). La epigastralgia fue el síntoma más referido (81,2 por ciento), la gastritis eritematosa fue el diagnóstico endoscópico más frecuente (76,8 por ciento) y la gastritis crónica moderada fue el diagnóstico histológico que más prevaleció (39,9 por ciento). Conclusiones: el estudio mostró que la prevalencia de la infección fue elevada(AU)
Introduction: Helicobacter pylori infection is the chronic bacterial disease most prevalent in humans. Objective: To Search the overall prevalence of this infection. Methods: A descriptive, longitudinal and prospective study was made in 138 dyspeptic patients. The diagnosis was made by serological, histological and culture methods. Results: The prevalence of Helicobacter pylori was 83.3 percent. Serology had 98 percent sensitivity and 34 percent of specificity, while histology had 83 percent and 25 percent respectively. Predominated in females (44.2 percent) and in the 31-40 years of age (18.8 percent). Epigastralgia was the most frequent symptom (81.2 percent), erythematous gastritis was the most common endoscopic diagnosis (76.8 percent) and moderate chronic gastritis histological was the most prevalent diagnosis (39.9 percent). Conclusions: The prevalence of infection was showed to be high in this study(AU)
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Humanos , Feminino , Adulto , Helicobacter pylori/citologia , Infecções por Helicobacter/epidemiologia , Gastrite/diagnóstico por imagemRESUMO
Introduction: Helicobacter pylori strains expressing cytotoxic CagA protein are more commonly associated with peptic ulceration, atrophic gastritis and gastric adenocarcinoma than those lacking CagA. Determination of anti-CagA antibodies, therefore, acquires a relevant clinical significance in the serological detection of H. pylori infection and disease risk prediction. However, the CagA-serology has been questioned due to the differences found in their performance evaluations in different populations. Objective: To obtain a recombinant CagA fragment useful for serodiagnosis of H. pylori infection Methods: A fragment of the cagA gene was cloned into a prokaryotic T7 RNA polymerase expression vector. A recombinant C-terminal His 6 -tagged CagA was expressed, subsequently solubilized with urea and purified by immobilized metal affinity chromatography. The performance of the recombinant protein was evaluated using 180 human serum samples with an in-house Western blot assay compared to the Helicoblot 2.1 reference test. Results: The expressed His 6 -tagged CagA showed an immunoreactive 80kDa band as was revealed by SDS-PAGE and Western blot analysis using two different specific anti-CagA polyclonal antibodies. The recombinant protein was successfully purified obtaining a 93% of purity. The performance analysis of the purified recombinant antigen showed good immunoreactivity and exhibited values of sensitivity, specificity and accuracy of 88.1%, 100% and 92.7%, respectively. Conclusion: The CagA fragment of the study may constitute a useful tool for serological diagnosis of CagA-positive H. pylori infection.
Introducción. Las cepas de Helicobacter pylori que expresan la citotoxina CagA, se asocian más frecuentemente con úlcera péptica, gastritis atrófica y adenocarcinoma gástrico que las que carecen de esta citotoxina. Por lo anterior, el determinar la presencia de anticuerpos anti-CagA adquiere gran importancia clínica en la detección serológica de la infección por H. pylori y la predicción del riesgo de enfermedades. Sin embargo, los métodos serológicos que emplean CagA han sido cuestionados debido a las diferencias encontradas en las evaluaciones de su desempeño en diversas poblaciones. Objetivo. Obtener un fragmento recombinante de la proteína CagA para el serodiagnóstico de la infección por H. pylori . Materiales y métodos. Un fragmento del gen cagA fue clonado en un vector de expresión procariota que contenía el promotor de la T7 ARN polimerasa. El fragmento de la proteína CagA con seis histidinas en la región C-terminal, se expresó, se solubilizó con urea y se purificó por cromatografía de afinidad con iones metálicos inmovilizados. El desempeño de la proteína recombinante se evaluó empleando un método in house de Western Blot y 180 sueros humanos. Los resultados se compararon con la prueba de referencia Helicoblot 2.1. Resultados. La proteína CagA expresada mostró una banda inmunorreactiva de 80 kDa en el Western Blot al emplear dos anticuerpos policlonales anti-CagA específicos. La proteína recombinante fue purificada hasta un 93 % de pureza y el análisis de desempeño del antígeno recombinante purificado mostró buena inmunorreacción y exhibió valores de sensibilidad, especificidad y exactitud de 88,1 %, 100 % y 92,7 %, respectivamente. Conclusiones. El fragmento de la proteína CagA del estudio puede constituir una herramienta útil para el diagnóstico serológico de la infección por cepas de H. pylori positivas para CagA.
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Adolescente , Adulto , Humanos , Pessoa de Meia-Idade , Adulto Jovem , Antígenos de Bactérias/sangue , Proteínas de Bactérias/sangue , Infecções por Helicobacter/sangue , Infecções por Helicobacter/diagnóstico , Helicobacter pylori , Antígenos de Bactérias/biossíntese , Antígenos de Bactérias/genética , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/genética , Clonagem Molecular , Expressão Gênica , Helicobacter pylori/genética , Helicobacter pylori/metabolismo , Proteínas Recombinantes , Testes SorológicosRESUMO
INTRODUCTION: Helicobacter pylori strains expressing cytotoxic CagA protein are more commonly associated with peptic ulceration, atrophic gastritis and gastric adenocarcinoma than those lacking CagA. Determination of anti-CagA antibodies, therefore, acquires a relevant clinical significance in the serological detection of H. pylori infection and disease risk prediction. However, the CagA-serology has been questioned due to the differences found in their performance evaluations in different populations. OBJECTIVE: To obtain a recombinant CagA fragment useful for serodiagnosis of H. pylori infection METHODS: A fragment of the cagA gene was cloned into a prokaryotic T7 RNA polymerase expression vector. A recombinant C-terminal His 6 -tagged CagA was expressed, subsequently solubilized with urea and purified by immobilized metal affinity chromatography. The performance of the recombinant protein was evaluated using 180 human serum samples with an in-house Western blot assay compared to the Helicoblot 2.1 reference test. RESULTS: The expressed His 6 -tagged CagA showed an immunoreactive 80kDa band as was revealed by SDS-PAGE and Western blot analysis using two different specific anti-CagA polyclonal antibodies. The recombinant protein was successfully purified obtaining a 93% of purity. The performance analysis of the purified recombinant antigen showed good immunoreactivity and exhibited values of sensitivity, specificity and accuracy of 88.1%, 100% and 92.7%, respectively. CONCLUSION: The CagA fragment of the study may constitute a useful tool for serological diagnosis of CagA-positive H. pylori infection.
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Antígenos de Bactérias/sangue , Proteínas de Bactérias/sangue , Infecções por Helicobacter/sangue , Infecções por Helicobacter/diagnóstico , Helicobacter pylori , Adolescente , Adulto , Antígenos de Bactérias/biossíntese , Antígenos de Bactérias/genética , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/genética , Clonagem Molecular , Expressão Gênica , Helicobacter pylori/genética , Helicobacter pylori/metabolismo , Humanos , Pessoa de Meia-Idade , Proteínas Recombinantes , Testes Sorológicos , Adulto JovemRESUMO
Pattern-recognition receptors have been highly conserved in evolution. They recognize danger signals including both pathogen- and damage-associated molecular patterns, also known as alarmins. Several signaling pathways leading to an inflammatory reaction as part of an effective defensive response, are thus triggered. RAGE, a receptor initially considered for advanced glycation end-products, is also known to be activated by several danger signals, thus functioning as a pattern-recognition receptor. As a new member of this family, attempts to unraveling its functioning show that RAGE activation not only results in innate immune response but also contributes to promote and shape the acquired immune reaction. As reported for other members of the family, RAGE presents many polymorphic variants and additional studies are needed to elucidate its significance in immune response and disease susceptibility. Here we describe recent advances unraveling RAGE functions, as well as its significance and challenges in immunobiology.
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Doenças Cardiovasculares/imunologia , Nefropatias Diabéticas/imunologia , Produtos Finais de Glicação Avançada/metabolismo , Polimorfismo Genético , Receptores Imunológicos/genética , Imunidade Adaptativa , Doenças Cardiovasculares/genética , Doenças Cardiovasculares/patologia , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/patologia , Regulação da Expressão Gênica , Humanos , Imunidade Inata , Inflamação , Ligantes , Especificidade de Órgãos , Receptor para Produtos Finais de Glicação Avançada , Receptores Imunológicos/imunologia , Transdução de SinaisRESUMO
INTRODUCTION: It is known that polymorphisms in C-terminal region of CagA influence gastric disease development on Helicobacter pylori infection. Additionally, the geographic distribution of these polymorphisms has been associated with the appearance of more severe gastroduodenal pathologies. Objective. To determine the CagA phosphorylation motifs pattern (EPIYA pattern) in Cuban H. pylori isolates, and to study its association with patient´s pathologies. MATERIALS AND METHODS: DNAs from 95 H. pylori cagA-positive strains were used to amplify the 3´ variable region of cagA gene by PCR using two different strategies. Additionally, new primers were designed to identify either Western or Eastern CagAEPIYA motiftype by PCR. To confirm the PCR results, PCR products from 14 representative isolates were purified and sequenced. RESULTS: The distribution of the EPIYA motif found was: 2 AB (2.1 %), 1 AC (1.1 %), 1 BC (1.1 %), 70 ABC (73.6 %), 19 ABCC (20 %), and 2 ABCCC (2.1 %). Sequencing analysis confirmed the PCR classification in the 14 studied strains and showed three strains with unusual nucleotide sequences, not reported before. Distribution of the EPIYA-ABC pattern was equivalent in all pathologies (78.9 % in gastric ulcer, 72.5 % in duodenal ulcer and 72.2 % in non-ulcer dyspepsia). CONCLUSION: The PCR results using the new primers confirmed that all studied strains carried the Western CagA type. No specific EPIYA motif was associated with peptic ulcer. This is the first report that shows EPIYA motif distribution in H. pylori isolates from the Caribbean region.