A-to-I editing on tRNAs: Biochemical, biological and evolutionary implications

AbstractInosine on transfer RNAs (tRNAs) are post-transcriptionally formed by a deamination mechanism of adenosines at positions 34, 37 and 57 of certain tRNAs. Despite its ubiquitous nature, the biological role of inosine in tRNAs remains poorly understood. Recent developments in the study of nucleotide modifications are beginning to indicate that the dynamics of such modifications are used in the control of specific genetic programs. Likewise, the essentiality of inosine-modified tRNAs in genome evolution and animal biology is becoming apparent. Here we review our current understanding on the role of inosine in tRNAs, the enzymes that catalyze the modification and the evolutionary link between such enzymes and other deaminases

Intoxicação por amônia em bovinos que receberam uréia extrusada ou granulada: alterações em alguns componentes bioquímicos do sangue

Twelve yearling Girolando steers never fed urea before were assigned randomly in two groups of six animals each. In both groups were administered intraruminally a single dose (0.5 g/kg BW) of extruded or prilled urea in order to induce ammonia poisoning. Plasma or serum levels of ammonia, urea, creatinine, glucose, L-lactate were determined. Hematocrit values were also recorded. Blood samples were taken before the administration of urea, at the onset of muscle tremors, at the first convulsive episode, and 240 minutes after the beginning of the urea feeding. Hyperammonemia already occured at the time of the first muscle tremors. Glucose and L-lactate levels were higher at the peak of the intoxication (convulsive episode), which were higher compared to the beginning of the experiment. Endogenous production of urea increased during the experiment due to hyperammonemia (r = 0.57), reaching peak levels at the end of the trials. Higher ammonia values lead to increased concentrations of L-lactate, glucose, urea, creatinine and hematocrit values. These results showed that high levels of ammonia increased glyconeogenesis, anaerobic glycolysis, the endogenous synthesis of urea and the level of dehydration. L-lactate and glucose were the best variables to monitor biochemical changes in cases of ammonia poisoning.Doze garrotes Girolando nunca alimentados com uréia foram distribuídos em dois grupos de seis animais cada, e induzidos a desenvolver um quadro de intoxicação por amônia através da administração de uréia extrusada ou granulada em dose única (0,5 g/ kg PV). Foram determinados no plasma ou soro os teores de amônia, glicose, L-lactato, uréia e creatinina, além do volume globular em sangue total nos seguintes momentos: antes da administração de uréia, no surgimento dos tremores, após o primeiro episódio convulsivo, e após 240 minutos do início do experimento. A hiperamoniemia ocorreu a partir dos primeiro tremores. Maiores glicemia e lactemia-L foram constatadas no momento do ápice da intoxicação (episódio convulsivo), os quais foram superiores ao tempo basal. A produção endógena de uréia aumentou no decorrer do experimento devido à hiperamoniemia (r = 0,57), atingindo seus valores mais altos ao término do experimento. Quanto maior foi o teor de amônia, maiores foram as concentrações de lactato-L, glicose, uréia, creatinina e volume globular. Estes resultados permitem concluir que o grau de hiperamoniemia aumentou a gliconeogênese, a glicólise anaeróbica, a síntese de uréia endógena e o grau de desidratação. Entre as variáveis estudadas os teores de glicose e de lactato-L foram os melhores indicadores para monitorar alterações bioquímicas na intoxicação pela amônia

Analysis of the molecular basis of Xanthomonas axonopodis pv. citri pathogenesis in Citrus limon

Xanthomonas axonopodis pathovar citri (Xac) causes bacterial citrus canker, a serious disease of most citrus species. Xanthomonas campestris pv. campestris (Xcc) is the causal agent of black rot disease in cruciferous plants. In Xcc, cell-cell signaling is mediated by diffusible signal factor (DSF). Synthesis of DSF depends on RpfB and RpfF. DSF perception and signal transduction have been suggested to involve a two-component system comprising RpfC and RpfG. It has been proposed that these proteins participate in a signal transduction system linking changes in the environment to the synthesis of DSF and the expression of virulence genes. Although the cluster of the rpf genes in Xac has synteny with the corresponding cluster in Xcc, two genes (rpfH and rpfI) are absent in Xac. To investigate DSF-mediated regulation during Xac-Citrus limon interaction, we constructed two strains of Xac, one with a mutation in the rpfF gene, leading to an inability to produce DSF, and one with a mutation in the rpfC gene leading to an overproduction of DSF. These mutants also show decreased levels of extracellular cyclic \u3b2-(1,2)-glucans and decreased production of endoglucanase and protease extracellular enzymes. The Xac DSF-deficient rpfF and the DSF-hyper producing rpfC mutants are both severely compromised in their ability to cause canker symptoms in lemon leaves compared to the wild-type. Here we provide evidence that rpf genes in Xac are involved in controlling virulence factors mediated by DSF

Analysis of the molecular basis of Xanthomonas axonopodis pv. citri pathogenesis in Citrus limon

Xanthomonas axonopodis pathovar citri (Xac) causes bacterial citrus canker, a serious disease of most citrus species. Xanthomonas campestris pv. campestris (Xcc) is the causal agent of black rot disease in cruciferous plants. In Xcc, cell-cell signaling is mediated by diffusible signal factor (DSF). Synthesis of DSF depends on RpfB and RpfF. DSF perception and signal transduction have been suggested to involve a two-component system comprising RpfC and RpfG. It has been proposed that these proteins participate in a signal transduction system linking changes in the environment to the synthesis of DSF and the expression of virulence genes. Although the cluster of the rpf genes in Xac has synteny with the corresponding cluster in Xcc, two genes (rpfH and rpfI) are absent in Xac. To investigate DSF-mediated regulation during Xac-Citrus limon interaction, we constructed two strains of Xac, one with a mutation in the rpfF gene, leading to an inability to produce DSF, and one with a mutation in the rpfC gene leading to an overproduction of DSF. These mutants also show decreased levels of extracellular cyclic \u3b2-(1,2)-glucans and decreased production of endoglucanase and protease extracellular enzymes. The Xac DSF-deficient rpfF and the DSF-hyper producing rpfC mutants are both severely compromised in their ability to cause canker symptoms in lemon leaves compared to the wild-type. Here we provide evidence that rpf genes in Xac are involved in controlling virulence factors mediated by DSF

A genome-wide association study with tissue transcriptomics identifies genetic drivers for classic bladder exstrophy

Classic bladder exstrophy represents the most severe end of all human congenital anomalies of the kidney and urinary tract and is associated with bladder cancer susceptibility. Previous genetic studies identified one locus to be involved in classic bladder exstrophy, but were limited to a restrict number of cohort. Here we show the largest classic bladder exstrophy genome-wide association analysis to date where we identify eight genome-wide significant loci, seven of which are novel. In these regions reside ten coding and four non-coding genes. Among the coding genes is EFNA1, strongly expressed in mouse embryonic genital tubercle, urethra, and primitive bladder. Re-sequence of EFNA1 in the investigated classic bladder exstrophy cohort of our study displays an enrichment of rare protein altering variants. We show that all coding genes are expressed and/or significantly regulated in both mouse and human embryonic developmental bladder stages. Furthermore, nine of the coding genes residing in the regions of genome-wide significance are differentially expressed in bladder cancers. Our data suggest genetic drivers for classic bladder exstrophy, as well as a possible role for these drivers to relevant bladder cancer susceptibility

Covid-T: A functional platform to monitor SARS-CoV-2-specific T cell responses in vaccinated individuals and COVID-19 recovered patient

La rápida propagación del coronavirus SARS-CoV-2, agente causal de la enfermedad pandémicaemergente COVID-19 y sus nuevas variantes, requiere del compromiso de la comunidad inmunológicapara comprender la magnitud y naturaleza de la respuesta inmunológica adaptativa desarrollada por pacientesrecuperados de COVID-19 e individuos vacunados con diferentes estrategias y protocolos, a los fines de implementar nuevas políticas sanitarias. En la actualidad, la determinación de la inmunidad contra SARS-CoV-2 sebasa principalmente en la detección de anticuerpos específicos y la determinación de su actividad neutralizante.Sin embargo, a pesar de la alta sensibilidad de estos ensayos, un número considerable de pacientes e individuos vacunados carecen de respuesta humoral detectable, o evidencian una disminución rápida de la mismaen el tiempo. Con el objetivo de estudiar la respuesta inmune celular desencadenada frente a SARS-CoV-2,en nuestro laboratorio desarrollamos la ?Plataforma COVID-T? estrategia integral optimizada dirigida a caracterizar y monitorear la respuesta de linfocitos T específicos de SARS-CoV-2 a partir de muestras de sangre deindividuos vacunados y/o recuperados de COVID-19. Esta plataforma permite evaluar la naturaleza, magnitudy persistencia de la inmunidad celular T generada tanto por la infección con SARS-CoV-2, como por distintosesquemas y protocolos de vacunación en diferentes poblaciones de individuos. Asimismo, permite evaluar larespuesta inmunológica T generada frente a nuevas variantes del virus e identificar individuos sanos resistentesa SARS-CoV-2 con inmunidad pre-existente hacia coronavirus estacionales.The rapid spread of the SARS-CoV-2, the causative agent of the emergent pandemic disease COVID-19, requires the urgent commitment of the immunology community to understand the adaptive immune response developed by COVID-19 convalescent patients and individuals vaccinated with different strategies and schemes, with the ultimate goal of implementing and optimizing health care and prevention policies. Currently, assessment of SARS-CoV-2-specific immunity is mainly focused on the measurement of the antibody titers and analysis of their neutralizing capacity. However, a considerable proportion of individuals lack humoral responses or show a progressive decline of SARS-CoV-2-specific neutralizing antibodies. In order to study the cellular response of convalescent patients and vaccinated individuals, we have developed the ‘COVID-T Platform’, an optimized strategy to study SARS-CoV-2-specific T cell responses. This platform allows assessment of the nature, magnitude and persistence of antigen-specific T-cell immunity in COVID-19-convalescent patients and vaccinated individuals. Moreover, it gives the opportunity to study cellular responses against emerging coronavirus variants and to identify individuals with cross-reactive immunity against seasonal coronaviruses.Fil: Manselle Cocco, Montana Nicolle. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Veigas, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Bach, Camila Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Blidner, Ada Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Cagnoni, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: D'alotto Moreno, Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Hockl, Pablo Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Mahmoud, Yamil Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Scheidegger, Marco Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Sirino, Alicia B.. Gobierno de la Ciudad Autonoma de Buenos Aires. Hospital General de Agudos Doctor Ignacio Pirovano .; ArgentinaFil: Torres, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Wiersba, Valeria. Universidad Austral. Hospital Universitario Austral; ArgentinaFil: Rabinovich, Gabriel Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin

Covid-T: A functional platform to monitor SARS-CoV-2-specific T cell responses in vaccinated individuals and COVID-19 recovered patient

La rápida propagación del coronavirus SARS-CoV-2, agente causal de la enfermedad pandémicaemergente COVID-19 y sus nuevas variantes, requiere del compromiso de la comunidad inmunológicapara comprender la magnitud y naturaleza de la respuesta inmunológica adaptativa desarrollada por pacientesrecuperados de COVID-19 e individuos vacunados con diferentes estrategias y protocolos, a los fines de implementar nuevas políticas sanitarias. En la actualidad, la determinación de la inmunidad contra SARS-CoV-2 sebasa principalmente en la detección de anticuerpos específicos y la determinación de su actividad neutralizante.Sin embargo, a pesar de la alta sensibilidad de estos ensayos, un número considerable de pacientes e individuos vacunados carecen de respuesta humoral detectable, o evidencian una disminución rápida de la mismaen el tiempo. Con el objetivo de estudiar la respuesta inmune celular desencadenada frente a SARS-CoV-2,en nuestro laboratorio desarrollamos la ?Plataforma COVID-T? estrategia integral optimizada dirigida a caracterizar y monitorear la respuesta de linfocitos T específicos de SARS-CoV-2 a partir de muestras de sangre deindividuos vacunados y/o recuperados de COVID-19. Esta plataforma permite evaluar la naturaleza, magnitudy persistencia de la inmunidad celular T generada tanto por la infección con SARS-CoV-2, como por distintosesquemas y protocolos de vacunación en diferentes poblaciones de individuos. Asimismo, permite evaluar larespuesta inmunológica T generada frente a nuevas variantes del virus e identificar individuos sanos resistentesa SARS-CoV-2 con inmunidad pre-existente hacia coronavirus estacionales.The rapid spread of the SARS-CoV-2, the causative agent of the emergent pandemic disease COVID-19, requires the urgent commitment of the immunology community to understand the adaptive immune response developed by COVID-19 convalescent patients and individuals vaccinated with different strategies and schemes, with the ultimate goal of implementing and optimizing health care and prevention policies. Currently, assessment of SARS-CoV-2-specific immunity is mainly focused on the measurement of the antibody titers and analysis of their neutralizing capacity. However, a considerable proportion of individuals lack humoral responses or show a progressive decline of SARS-CoV-2-specific neutralizing antibodies. In order to study the cellular response of convalescent patients and vaccinated individuals, we have developed the ‘COVID-T Platform’, an optimized strategy to study SARS-CoV-2-specific T cell responses. This platform allows assessment of the nature, magnitude and persistence of antigen-specific T-cell immunity in COVID-19-convalescent patients and vaccinated individuals. Moreover, it gives the opportunity to study cellular responses against emerging coronavirus variants and to identify individuals with cross-reactive immunity against seasonal coronaviruses.Fil: Manselle Cocco, Montana Nicolle. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Veigas, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Bach, Camila Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Blidner, Ada Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Cagnoni, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: D'alotto Moreno, Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Hockl, Pablo Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Mahmoud, Yamil Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Scheidegger, Marco Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Sirino, Alicia B.. Gobierno de la Ciudad Autonoma de Buenos Aires. Hospital General de Agudos Doctor Ignacio Pirovano .; ArgentinaFil: Torres, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Wiersba, Valeria. Universidad Austral. Hospital Universitario Austral; ArgentinaFil: Rabinovich, Gabriel Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin