Transgenerational inheritance of acquired epigenetic signatures at CpG islands in mice.

Transgenerational epigenetic inheritance in mammals remains a debated subject. Here, we demonstrate that DNA methylation of promoter-associated CpG islands (CGIs) can be transmitted from parents to their offspring in mice. We generated DNA methylation-edited mouse embryonic stem cells (ESCs), in which CGIs of two metabolism-related genes, the Ankyrin repeat domain 26 and the low-density lipoprotein receptor, were specifically methylated and silenced. DNA methylation-edited mice generated by microinjection of the methylated ESCs exhibited abnormal metabolic phenotypes. Acquired methylation of the targeted CGI and the phenotypic traits were maintained and transmitted across multiple generations. The heritable CGI methylation was subjected to reprogramming in parental PGCs and subsequently reestablished in the next generation at post-implantation stages. These observations provide a concrete step toward demonstrating transgenerational epigenetic inheritance in mammals, which may have implications in our understanding of evolutionary biology as well as the etiology, diagnosis, and prevention of non-genetically inherited human diseases.

Examining the factors that affect structural repetition in question answering.

We present two experiments that examine structural priming in the single-trial phone-call paradigm introduced by Levelt and Kelter (Cognitive psychology, 14 (1), 78-106, 1982). Experimenters called businesses and asked either What time do you close? or At what time do you close? Participants were more likely to produce a prepositional response (At 7 o'clock vs. 7 o'clock) following a prepositional question than following a non-prepositional question. Experiments 1 and 2 attempted to strengthen the priming effect by having the experimenters engage in a brief interaction with the participant before asking the What time…? question. The interactions did not reliably affect the observed priming effect. An analysis across experiments demonstrated that the priming effect found in this paradigm is generally smaller than the average structural priming effect (as reported in Mahowald, James, Futrell, & Gibson, Journal of Memory and Language, 91, 5-27, 2016), but within the range of the effects that are observed in different structural priming paradigms.

Social-ecological memory and responses to biodiversity change in a Bribri Community of Costa Rica.

Social-ecological memory (SEM) is an analytical construct used to consider the ways by which people can draw upon biological materials and social memory to reorganize following a disturbance. Since its introduction into the literature, there have been few cases that have considered its use. We use ethnographic methods to study Bribri people's commercial crops that have been invaded by different fungal pathogens and have undergone several disturbance recovery cycles. We show how the Bribri have used social memory and ecological memory together, dynamic interactions of legacies and reservoirs, and the role of mobile links for reorganization following the impact of fungal diseases. Insights from the Bribri indicate that protection of biodiversity, management practices, and adoption of new species and varieties are all crucial. The SEM concept extends the understanding of Indigenous knowledge, to include linkages to other peoples' memory and to landscapes as reservoirs of SEM. An understanding of how people use SEM to respond to disturbances is necessary as biodiversity changes are expected to become more pronounced in the future.

Interspecies Chimerism with Mammalian Pluripotent Stem Cells.

Interspecies blastocyst complementation enables organ-specific enrichment of xenogenic pluripotent stem cell (PSC) derivatives. Here, we establish a versatile blastocyst complementation platform based on CRISPR-Cas9-mediated zygote genome editing and show enrichment of rat PSC-derivatives in several tissues of gene-edited organogenesis-disabled mice. Besides gaining insights into species evolution, embryogenesis, and human disease, interspecies blastocyst complementation might allow human organ generation in animals whose organ size, anatomy, and physiology are closer to humans. To date, however, whether human PSCs (hPSCs) can contribute to chimera formation in non-rodent species remains unknown. We systematically evaluate the chimeric competency of several types of hPSCs using a more diversified clade of mammals, the ungulates. We find that naïve hPSCs robustly engraft in both pig and cattle pre-implantation blastocysts but show limited contribution to post-implantation pig embryos. Instead, an intermediate hPSC type exhibits higher degree of chimerism and is able to generate differentiated progenies in post-implantation pig embryos.

Evaluación del método químico-enzimático de descelularización para la obtención de matrices extracelulares de tráquea en el modelo porcino / Avaliação do método químico-enzimático de descelularização para a obtenção de matrizes extracelulares de traqueia no modelo suíno / Evaluation of the chemical-enzymatic decellularization method for obtaining extracellular trachea matrixes in a porcine model

Diferentes enfermedades afectan la tráquea y deterioran la calidad de vida. La ingeniería tisular es una alternativa terapéutica para los pacientes con esas enfermedades: matrices de tráquea descelularizadas y sembradas con células del receptor no generan respuesta inmune y pueden prevenir incluso el rechazo de zootrasplantes. Objetivo: evaluar un método de descelularización para obtener matrices extracelulares de tráquea en el modelo porcino. Materiales y métodos: a partir de 5 tráqueas porcinas se formaron dos grupos de estudio, controles y tratados con un método químico-enzimático. Se hizo análisis histológico con hematoxilina-eosina, coloración tricrómica de Masson y safranina O. Se evaluaron las propiedades biomecánicas de ambos grupos, mediante la determinación del módulo de Young, la fuerza máxima y el porcentaje de deformación. Resultados: en las muestras tratadas se observó una disminución del 66 % del contenido celular en comparación con los controles. Se preservó el colágeno y se detectó reducción de los glucosaminoglucanos. Las pruebas biomecánicas revelaron una diferencia estadísticamente significativa del porcentaje de deformación, sin alteración de los demás parámetros. Conclusiones: el método evaluado demostró ser eficiente para descelularizar tráqueas de cerdo, con una disminución importante en el costo y el tiempo de tratamiento, por lo que podría ser una buena opción en las condiciones socioeconómicas de Colombia...

Different diseases may affect the trachea and, therefore, the quality of life. Tissue engineering may be a therapeutic alternative for patientswith such diseases, using decellularized trachea matrixes seeded with cells from the recipient, which do not generate immune response and may even prevent rejection of zoo-transplants. Objective: To evaluate a decellularization method to obtain tracheal extracellular matrixes in the porcine model. Materials and methods: Two study groups, treated and control, were obtained from 5 porcine tracheas.A chemical-enzymatic method for decellularization was used. Histological analyses were performed with hematoxylin-eosin, Masson’s trichromic stain and safranin O. Biomechanical properties of both groups were evaluated by determining the Young modulus, maximum strength and deformation rate. Results: Compared to the controls, there was a 66 % decrease in the cell content in the treated specimens. Collagen was preserved and a reduction of glycosaminoglycans was detected. Biomechanical tests revealed a significant difference in the percentage of deformation, with no alteration of the remaining parameters. Conclusions: The evaluated decellularization method proved to be efficient to reduce the cellular content of porcine tracheas, with a considerable decrease in cost and production time. These advantages could make it a good option for the socio-economic Colombian conditions...

Diferentes doenças afetam a traqueia e deterioram a qualidade de vida. A engenheira tisular é uma alternativa terapêutica para os pacientes com essas doenças: matrizes de traqueia descelularizadas e semeadas com células do receptor não geram resposta imune e podem prevenir incluso a rejeição de zoo-transplantes. Objetivo: avaliar um método de descelularização para obter matrizes extracelulares de traqueia no modelo suíno. Materiais e métodos: a partir de 5 traqueias suínas se formaram dois grupos de estudo, controles e tratados com um método químico-enzimático. Se fez análise histológico com hematoxilina-eosina, corante tricrómica de Masson e safranina O. Se avaliaram as propriedades biomecânicas de ambos grupos, mediante a determinação do módulo de Young, a força máxima e a porcentagem de deformação. Resultados: Nas amostras tratadas se observou uma diminuição de 66 % do conteúdo celular em comparação com os controles. Se preservou o colágenoe se detectou redução dos glucosaminoglucanos. As provas biomecânicas revelaram uma diferença estatisticamente significativa da porcentagem de deformação, sem alteração dos demais parâmetros. Conclusões: O método avaliado demostrou ser eficiente para descelularizar traqueias de porco, com uma diminuição importante no custo e o tempo de tratamento, pelo que poderia ser uma boa opção nas condições socioeconómicas da Colômbia...

Shape and surface chemistry effects on the cytotoxicity and cellular uptake of metallic nanorods and nanospheres.

Metallic nanoparticles (such as gold and silver) have been intensely studied for wound healing applications due to their ability to be easily functionalized, possess antibacterial properties, and their strong potential for targeted drug release. In this study, rod-shaped silver nanorods (AgNRs) and gold nanorods (AuNRs) were fabricated by electron beam physical vapor deposition (EBPVD), and their cytotoxicity toward human skin fibroblasts were assessed and compared to sphere-shaped silver nanospheres (AgNSs) and gold nanospheres (AuNSs). Results showed that the 39.94 nm AgNSs showed the greatest toxicity with fibroblast cells followed by the 61.06 nm AuNSs, ∼556 nm × 47 nm (11.8:1 aspect ratio) AgNRs, and the ∼534 nm × 65 nm (8.2:1 aspect ratio) AuNRs demonstrated the least amount of toxicity. The calculated IC50 (50% inhibitory concentration) value for the AgNRs exposed to fibroblasts was greater after 4 days of exposure (387.3 µg mL(-1)) compared to the AgNSs and AuNSs (4.3 and 23.4 µg mL(-1), respectively), indicating that these spherical metallic nanoparticles displayed a greater toxicity to fibroblast cells. The IC50 value could not be measured for the AuNRs due to an incomplete dose response curve. The reduced cell toxicity with the presently developed rod-shaped nanoparticles suggests that they may be promising materials for use in numerous biomedical applications.

Variedad de la presentación citogenética en el síndrome de turner, prenatal y postnatal / Cytogenetics variety of presentation turner syndrome, prenatal and postnatal

Antecedentes: El síndrome de Turner (ST) es causado por la ausencia total o parcial del cromosoma X y posee una gran variedad en su presentación citogenética. Objetivos: Determinar la variedad de presentación citogenética y la existencia de diferencias entre los casos diagnosticados in útero y los de diagnóstico postnatal, en pacientes con ST en dos laboratorios de referencia de Cali, Colombia. Métodos: Se realizó un estudio observacional descriptivo de corte transversal, se incluyeron pacientes con diagnóstico de ST, cuyo cariotipo se realizó entre los años 2000 y 2012, en los laboratorios de citogenética de la Universidad del Valle y un instituto de genética de Cali, Colombia. Se recolectó información del reporte del cariotipo, tipo de muestra y tiempo de realización del diagnóstico y se determinó frecuencias y asociaciones estadísticas entre las variables a estudiar. Resultados: Se incluyeron 181 pacientes con fórmula cromosómica compatible con ST; 69 fueron diagnosticados in útero, los demás, en recién nacidos vivos, infantes o adultos. La fórmula cromosómica 45 X0 se encontró en el 95,6 por ciento de los casos de diagnóstico prenatal y 58 por ciento de los de diagnóstico postnatal. Se aplicó la prueba del test exacto de Fisher, comparando los múltiples subgrupos de la variedad de presentación citogenética de diagnóstico prenatal y postnatal, encontrándose diferencias estadísticamente significativas en la distribución de las dos poblaciones evaluadas (p<0,001). Conclusiones: Existen diferencias significativas en los cariotipos de los pacientes con ST diagnosticados in útero, respecto a los diagnosticados en vida extrauterina. Se postula que esa diferencia tendría una explicación biológica sobre la posibilidad de muerte in útero por la ausencia total del cromosoma X.

Background: Turner syndrome is caused by the complete or partial absence of chromosome X and has a great variety in their cytogenetic presentation. Objectives: To determine the variety of cytogenetic presentation and the presence of differences between cases diagnosed in uterus and postnatally, in patients with Turner syndrome at two reference laboratories of Cali, Colombia. Methods: A descriptive cross-sectional study was performed. We included patients with cytogenetic diagnosis of Turner syndrome performed between 2000 and 2012 at cytogenetic laboratories of Universidad del Valle and a genetic institute in Cali, Colombia. The information of karyotype result, type of sample and the diagnosis moment was collected, determining frequencies and statistical associations. Results: 181 patients with Turner's chromosomic presentation; 69 were diagnosed in uterus, the other as live newborns, infants or adults. Chromosomal formula 45X0 was found in 95.6 percent of cases with prenatal diagnosis and 58 percent of postnatal diagnosis. Fisher's test was applied, comparing the cytogenetic presentations of prenatal and postnatal diagnosis, statistically significant difference in the distribution of the two populations evaluated was found (p<0.001). Conclusions: There are significant differences in the karyotypes of patients with ST diagnosed in utero, compared to those diagnosed in postnatal life. We hypothesize that this difference would have a biological explanation due to a higher probability of death in utero by the complete absence of chromosome X.

Negative plant-soil feedback predicts tree-species relative abundance in a tropical forest.

The accumulation of species-specific enemies around adults is hypothesized to maintain plant diversity by limiting the recruitment of conspecific seedlings relative to heterospecific seedlings. Although previous studies in forested ecosystems have documented patterns consistent with the process of negative feedback, these studies are unable to address which classes of enemies (for example, pathogens, invertebrates, mammals) exhibit species-specific effects strong enough to generate negative feedback, and whether negative feedback at the level of the individual tree is sufficient to influence community-wide forest composition. Here we use fully reciprocal shade-house and field experiments to test whether the performance of conspecific tree seedlings (relative to heterospecific seedlings) is reduced when grown in the presence of enemies associated with adult trees. Both experiments provide strong evidence for negative plant-soil feedback mediated by soil biota. In contrast, above-ground enemies (mammals, foliar herbivores and foliar pathogens) contributed little to negative feedback observed in the field. In both experiments, we found that tree species that showed stronger negative feedback were less common as adults in the forest community, indicating that susceptibility to soil biota may determine species relative abundance in these tropical forests. Finally, our simulation models confirm that the strength of local negative feedback that we measured is sufficient to produce the observed community-wide patterns in tree-species relative abundance. Our findings indicate that plant-soil feedback is an important mechanism that can maintain species diversity and explain patterns of tree-species relative abundance in tropical forests.

Two fungal symbioses collide: endophytic fungi are not welcome in leaf-cutting ant gardens.

Interactions among the component members of different symbioses are not well studied. For example, leaf-cutting ants maintain an obligate symbiosis with their fungal garden, while the leaf material they provide to their garden is usually filled with endophytic fungi. The ants and their cultivar may interact with hundreds of endophytic fungal species, yet little is known about these interactions. Experimental manipulations showed that (i) ants spend more time cutting leaves from a tropical vine, Merremia umbellata, with high versus low endophyte densities, (ii) ants reduce the amount of endophytic fungi in leaves before planting them in their gardens, (iii) the ants' fungal cultivar inhibits the growth of most endophytes tested. Moreover, the inhibition by the ants' cultivar was relatively greater for more rapidly growing endophyte strains that could potentially out-compete or overtake the garden. Our results suggest that endophytes are not welcome in the garden, and that the ants and their cultivar combine ant hygiene behaviour with fungal inhibition to reduce endophyte activity in the nest.

Síndrome de la Silla Turca Vacía con Panhipopituitarismo y diabetes insípida / Syndrome chear empty with panhypopituatarism and insipidus diabetes

Presentamos el caso de una niña de 1 año y 6 meses con baja talla, obesidad, panhipopituitarismo, diabetes insípida y trastornos visuales que en el examen postmortem mostró atrofia cerebral secundaria a una encefalopatía difusa, frecuentes neuronas calcificadas en corteza cerebral, núcleos de la base y, particularmente, en el hipotálamo, nervios ópticos con moderada atrofia, tallo hipofisario filiforme y silla turca vacía con hipófisis en el dorso de la concavidad. Se discute la probable patogenia de los hallazgos anatomopatológicos en el contexto de la literatura pertinente

Síndrome de la Silla Turca Vacía con Panhipopituitarismo y diabetes insípida / Syndrome chear empty with panhypopituatarism and insipidus diabetes

Presentamos el caso de una niña de 1 año y 6 meses con baja talla, obesidad, panhipopituitarismo, diabetes insípida y trastornos visuales que en el examen postmortem mostró atrofia cerebral secundaria a una encefalopatía difusa, frecuentes neuronas calcificadas en corteza cerebral, núcleos de la base y, particularmente, en el hipotálamo, nervios ópticos con moderada atrofia, tallo hipofisario filiforme y silla turca vacía con hipófisis en el dorso de la concavidad. Se discute la probable patogenia de los hallazgos anatomopatológicos en el contexto de la literatura pertinente