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Contribución de los autores:Luis Enrique Paternina: diseño del estudio, recolección de muestras y desarrollo de los análisis genéticos Daniel Verbel-Vergara: recolección de muestras y ensayos moleculares Eduar Elías Bejarano: diseño del estudio, coordinación del trabajo de laboratorio y análisis genéticos Todos los autores participaron en la redacción del manuscrito. Introducción. En las últimas décadas, el análisis de los genes mitocondriales se ha utilizado en los estudios poblacionales y filogenéticos de garrapatas, lo cual ha permitido numerosos avances en la sistemática de estos ácaros. El gen mitocondrial de la subunidad 16S del ARN ribosómico (16S) es uno de los más usados, mientras que el gen mitocondrial de la citocromo oxidasa 1 (COX1) se ha empleado recientemente y se propone como un marcador genético alternativo frente al 16S. Objetivo. Evaluar la utilidad de los genes 16S y COX1 en los estudios genéticos de las garrapatas mediante el análisis de secuencias en tres especies de la región Caribe de Colombia.Resultados. El análisis de secuencias mostró que los dos genes permitieron identificar las tres especies con mucha confiabilidad y con niveles de divergencia genética interespecífica relativamente similares (19 a 22 %), aunque solo el gen COX1 permitió detectar la variabilidad genética intraespecífica (hasta de ~0,8 %). El análisis de saturación de sustituciones indicó que el gen 16S no se saturó con transiciones, mientras que el COX1 mostró saturación a partir de distancias de ~17 %. Conclusión. Los resultados indicaron que el gen 16S parece tener mejores características para los análisis filogenéticos interespecíficos dada su alta divergencia genética y baja saturación de transiciones, mientras que el gen COX1 parece ser más útil para estudios de variabilidad genética intraespecífica. Sin embargo, dado que el estudio se hizo a escala local, se requieren más investigaciones en diferentes escalas biogeográficas para establecer su utilidad en circunstancias más amplias y complejas. Introduction: In recent decades the analysis of mitochondrial genes has been used for population and phylogenetic studies of ticks allowing many advances in their systematics. Mitochondrial ribosomal 16S (16S) subunit is one of the most frequently used among those genes available for tick analysis, whereas cytochrome oxidase gene 1 (COX1) has recently been used and proposed as an alternative to the traditional 16S gene marker. Objective: To evaluate the usefulness of 16S and COX1 in genetic studies of ticks by analyzing sequences of three species commonly found in the Caribbean region of Colombia. Results: The analysis of both genes sequences allowed us to identify the three species with high levels of confidence and interspecific genetic divergence (19-22%), although only COX1 allowed us to detect intraspecific genetic variability (up to ~0.8%). A substitution saturation analysis indicated that the 16S gene was not saturated with transitions while the COX1 gene showed saturation distances starting at ~17%. Conclusion: Our...

Background Nuclear processes such as transcription and RNA maturation can be impacted by subnuclear compartmentalization in condensates and nuclear bodies. Here, we characterize the nature of nuclear granules formed by REST corepressor 2 (RCOR2), a nuclear protein essential for pluripotency maintenance and central nervous system development. Results Using biochemical approaches and high-resolution microscopy, we reveal that RCOR2 is localized in nuclear speckles across multiple cell types, including neurons in the brain. RCOR2 forms complexes with nuclear speckle components such as SON, SRSF7, and SRRM2. When cells are exposed to chemical stress, RCOR2 behaves as a core component of the nuclear speckle and is stabilized by RNA. In turn, nuclear speckle morphology appears to depend on RCOR2. Specifically, RCOR2 knockdown results larger nuclear speckles, whereas overexpressing RCOR2 leads to smaller and rounder nuclear speckles. Conclusion Our study suggests that RCOR2 is a regulatory component of the nuclear speckle bodies, setting this co-repressor protein as a factor that controls nuclear speckles behavior.

One manner in which G protein-coupled receptors potentiate, increase, and change their functionality is through the formation of heteromers in a specific cellular context. Previously, we have shown that dopamine D1 receptor (D1R) and the corticotropin releasing factor receptor type-2α (CRF2α) heteromerize in HEK293T cells, enabling D1R to mobilize intracellular calcium in response to D1R agonists. In this study, we further investigated the pharmacological properties of the CRF2α-D1R heteromer and the consequences of the heteromerization in their signaling and subcellular localization when both receptors are co-expressed in HEK293T cells. Using immunoprecipitation assays, we observed that the addition of 10 μM dopamine in the incubation medium significantly decreased the amount of CRF2α on the cell surface of cells expressing both receptors. The presence of agonists of both receptors increased the interaction between CRF2α and D1R as assessed by co-immunoprecipitation. However, the presence of agonists of both receptors resulted in a lesser efficient activation of the mitogen-activated protein kinase/extracellular signal-regulated kinase. Using a synaptosomal preparation of rat prefrontal cortex devoid of post-synaptic elements, we found that CRF2α and D1R co-localize in synaptic terminals of the rat medial prefrontal cortex and that the simultaneous activation of both receptors also occluded phosphorylation of extracellular signal-regulated kinase. These results strengthen the idea that the heteromer CRF2a-D1R is an entity functionally different from each receptor that composes it and suggests that its formation is enhanced by CRF and dopamine co-transmission, as occurs in stress and addiction.

Introducción. Las técnicas de biología molecular han permitido ampliar el conocimiento sobre las fuentes de ingestión de sangre de los insectos vectores. Sin embargo, la utilidad de estas técnicas depende de la cantidad de sangre ingerida y del proceso de digestión en el insecto.Objetivo. Determinar el tiempo límite de detección del gen citocromo b (Cyt b) de humanos en hembras de Lutzomyia evansi alimentadas experimentalmente.Materiales y métodos. Se evaluaron ocho grupos de hembras de L. evansi alimentadas con sangre humana, las cuales fueron sacrificadas en intervalos de 24 horas desde el momento de la ingestión sanguínea. Se extrajo el ADN total de cada hembra y se amplificó un segmento de 358 pb del gen Cyt b. Los productos amplificados fueron sometidos a un análisis de polimorfismos en la longitud de los fragmentos de restricción (Restriction Fragment Length Polymorphism, RFLP), con el fin de descartar falsos positivos.Resultados. El segmento del gen Cyt b de humanos fue detectado en 86 % (49/57) de las hembras de L. evansi a partir de las 0 horas y hasta 168 horas después de la ingestión de sangre. En 7 % (4/57) de los individuos se amplificó el ADN del insecto y en el 7 % restante no se amplificó la banda de interés. No se encontraron diferencias estadísticas en cuanto a la amplificación del segmento del gen Cyt b de humanos ni al número de muestras amplificadas entre los grupos de hembras sacrificadas a distintas horas después de la ingestión.Conclusión. El segmento del gen Cyt b de humanos fue detectable en hembras de L. evansi hasta 168 horas después de la ingestión de sangre.

Adversity is particularly pernicious in early life, increasing the likelihood of developing psychiatric disorders in adulthood. Juvenile and adult rats exposed to social isolation show differences in anxiety-like behaviors and significant changes in dopamine (DA) neurotransmission in the nucleus accumbens (NAc). Brain response to stress is partly mediated by the corticotropin-releasing factor (CRF) system, composed of CRF and its two main receptors, CRF-R1 and CRF-R2. In the NAc shell of adult rats, CRF induces anxiety-like behavior and changes local DA balance. However, the role of CRF receptors in the control of neurotransmission in the NAc is not fully understood, nor is it known whether there are differences between life stages. Our previous data showed that infusion of a CRF-R1 antagonist into the NAc of juvenile rats increased DA levels in response to a depolarizing stimulus and decreased basal glutamate levels. To extend this analysis, we now evaluated the effect of a CRF-R1 antagonist infusion in the NAc of adult rats. Here, we describe that the opposite occurred in the NAc of adult compared to juvenile rats. Infusion of a CRF-R1 antagonist decreased DA and increased glutamate levels in response to a depolarizing stimulus. Furthermore, basal levels of DA, glutamate, and γ-Aminobutyric acid (GABA) were similar in juvenile animals compared to adults. CRF-R1 protein levels and localization were not different in juvenile compared to adult rats. Interestingly, we observed differences in the signaling pathways of CRF-R1 in the NAc of juveniles compared to adult rats. We propose that the function of CRF-R1 receptors is differentially modulated in the NAc according to life stage.