Transcription factor roles in the local adaptation to temperature in the Andean Spiny Toad Rhinella spinulosa.

Environmental temperature strongly influences the adaptation dynamics of amphibians, whose limited regulation capabilities render them susceptible to thermal oscillations. A central element of the adaptive strategies is the transcription factors (TFs), which act as master regulators that orchestrate stress responses, enabling species to navigate the fluctuations of their environment skillfully. Our study delves into the intricate relationship between TF expression and thermal adaptation mechanisms in the Rhinella spinulosa populations. We sought to elucidate the dynamic modulations of TF expression in prometamorphic and metamorphic tadpoles that inhabit two thermally contrasting environments (Catarpe and El Tatio Geyser, Chile) and which were exposed to two thermal treatments (25 °C vs. 20 °C). Our findings unravel an intriguing dichotomy in response strategies between these populations. First, results evidence the expression of 1374 transcription factors. Regarding the temperature shift, the Catarpe tadpoles show a multifaceted approach by up-regulating crucial TFs, including fosB, atf7, and the androgen receptor. These dynamic regulatory responses likely underpin the population's ability to navigate thermal fluctuations effectively. In stark contrast, the El Tatio tadpoles exhibit a more targeted response, primarily up-regulating foxc1. This differential expression suggests a distinct focus on specific TFs to mitigate the effects of temperature variations. Our study contributes to understanding the molecular mechanisms governing thermal adaptation responses and highlights the resilience and adaptability of amphibians in the face of ever-changing environmental conditions.

Northern and central Chile still free of emerging flaviviruses in mosquitoes (Diptera: Culicidae).

Geographic isolation and strict control limits in border areas have kept Chile free from various pathogens, including Flavivirus. However, the scenario is changing mainly due to climate change, the reintroduction of more aggressive mosquitoes, and the great wave of migration of people from endemic countries in recent years. Hence, it is necessary to surveillance mosquitoes to anticipate a possible outbreak in the population and take action to control it. This study aimed to investigate the presence of Flavivirus RNA by molecular tools with consensus primers in mosquitoes collected in the extreme north and central Chile. From 2019 to 2021, a prospective study was carried out in localities of Northern and part of Central Chile. Larvae, pupae, and adults of mosquitoes were collected in rural and urban sites in each locality. The collected samples were pooled by species and geographical location and tested using RT-PCR and RT-qPCR to determine presence of Flavivirus. 3085 specimens were collected, the most abundant specie Culex quinquefasciatus in the North and Aedes (Ochlerotatus) albifasciatus in the Center of Chile. Both genera are associated with Flavivirus transmission. However, PCR and RT-PCR did not detect Flavivirus RNA in the mosquitoes studied. These negative results indicate we are still a free Flavivirus country, which is reaffirmed by the non-existence of endemic human cases. Despite this, routine surveillance of mosquitoes and the pathogens they carry is highly recommended to evaluate each area-specific risk of vector-borne transmission.

Análisis de modelos tipo SEIR utilizados en los inicios de la pandemia COVID-19 reportados en revistas de alto impacto / Analysis of SEIR-type models used at the beginning of COVID-19 pandemic reported in high-impact journals

Introducción El modelo matemático-epidemiológico Susceptible-Expuesto-Infectado-Recuperado (SEIR) ha sido empleado exhaustivamente en el contexto actual de la pandemia COVID-19. En sus inicios de una manera prevalente, donde se buscaba predecir la carga hospitalaria y evaluar las medidas sanitarias para contener su propagación. En este sentido, se han evidenciado fallas en las predicciones de los primeros modelos publicados. Se considera necesario evaluar las diferencias en el planteamiento y verificación de los modelos. Objetivos Categorizar las publicaciones científicas de revistas de alto impacto que propusieron modelos tipo SEIR para modelar la pandemia COVID-19 en sus inicios. Métodos Realizamos una revisión sistemática de los artículos publicados en revistas indexadas en , de primer cuartil y con factor de impacto mayor que dos, que cumplían con los criterios de selección e inclusión siguiendo los estándares PRISMA-ScR. Incluimos un total de 32 artículos que fueron evaluados según características demográficas como el mes de recepción y publicación, el país de origen de la información, la materia temática de la revista, y las características del modelamiento como la presencia de compartimentos adicionales, análisis gráfico, planteamiento de modelo conceptual, interpretación del número reproductivo básico y estimación de los parámetros empleados. Resultados Los artículos publicados en revistas del área médica y salud fueron predominantes en los meses de febrero a julio de 2020. Estos artículos emplearon con mayor frecuencia datos procedentes de China y se centraron mayoritariamente en modelos SEIR o con compartimento de cuarentena completa. Los artículos publicados en revistas del área matemática fueron predominantes en el período de agosto a diciembre de 2020, y emplearon datos procedentes de diversas regiones del mundo, considerando mayor diversidad de compartimentos como pacientes asintomáticos o en cuarentena parcial o completa. Conclusiones Los artículos analizados en su mayoría emplean modelos tipo SEIR ampliados con compartimentos adicionales. Existen discrepancias en la amplitud y calidad metodológica de los artículos publicados, según la materia temática de la revista. Se recomienda la unificación de criterios de calidad para la descripción de los modelos en cualquier revista.

Introduction The Susceptible-Exposed-Infected-Recovered (SEIR) mathematical-epidemiological model has been exhaustively used since de beggining of the COVID-19 pandemic. These models intended to predict hospital burden and evaluate health measures to contain its spread. In this sense, flaws have been evidenced in the predictions of the first published models. It is considered necessary to evaluate the differences in the approach and verification of the models. Objectives We carried out a systematic review of the articles published in journals indexed in the Web of Science, of the first quartile and with an impact factor greater than two, that met the selection and inclusion criteria following the PRISMA-ScR standards. We included a total of 32 articles, which were evaluated according to demographic characteristics such as the month of receipt and publication, the country of origin of the information, the subject matter of the journal, and the characteristics of the modeling such as the presence of additional compartments, graphical analysis, conceptual model approach, interpretation of the basic reproductive number, and estimation of parameters. Methods Articles published in medical and health journals were predominant from February to July 2020. These articles most frequently used data from China and mostly focused on SEIR or full quarantine compartment models. The articles published in journals in mathematics were predominant from August to December 2020. Models used data from different world regions, considering a greater diversity of compartments such as asymptomatic patients or partial or complete quarantine. Results The articles analyzed mostly use SEIR-type models expanded with additional compartments. There are discrepancies in the breadth and methodological quality of the articles published according to the journal's subject matter. The unification of quality criteria for describing the models in any journal is recommended. Conclusions The articles analyzed mostly use SEIR-type models expanded with additional compartments. There are discrepancies in the breadth and methodological quality of the articles published according to the journal's subject matter. The unification of quality criteria for describing the models in any journal is recommended.

Simulation Model for Hashimoto Autoimmune Thyroiditis Disease.

Hashimoto thyroiditis (HT) is a pathology that often causes a gradual thyroid insufficiency in affected patients due to the autoimmune destruction of this gland. The cellular immune response mediated by T helper lymphocytes TH1 and TH17 can induce the HT disease. In this pathologic condition, there is an imbalance between the TH17 and Treg lymphocytes as well as a gut microbiota dysfunction. The objective of this work was to describe the interactions of the cell subpopulations that participate in HT. To achieve this goal, we generated a mathematical model that allowed the simulation of different scenarios for the dynamic interaction between thyroid cells, the immune system, and the gut microbiota. We used a hypothetical-deductive design of mathematical modeling based on a system of ordinary differential equations, where the state variables are the TH1, TH17, and Treg lymphocytes, the thyrocytes, and the bacteria from gut microbiota. This work generated a compartmental model of the cellular immune response occurring in the thyroid gland. It was observed that TH1 and TH17 lymphocytes could increase the immune cells' activity, as well as activate effector cells directly and trigger the apoptosis and inflammation processes of healthy thyrocytes indirectly. Likewise, the model showed that a reduction in Treg lymphocytes could increase the activity of TH17 lymphocytes when an imbalance of the gut microbiota composition occurred. The numerical results highlight the TH1, TH17, and bacterial balance of the gut microbiota activities as important factors for the development of HT disease.

Morphological and molecular analysis of cryptic native and invasive freshwater snails in Chile.

Species delimitation in minute freshwater snails is often difficult to perform using solely shell morphology. The problem intensifies when invasive species spread within the distribution range of morphologically similar native species. In Chile, the Truncatelloidean snails are represented by the native genera Heleobia and Potamolithus plus the invasive mudsnail Potamopyrgus antipodarum, which can easily be confused. Using an integrative approach, we performed molecular phylogenetic analysis and studied reproductive and morphological features to identify superficially similar forms inhabiting the central area of the country. Truncatelloidean snails were identified in 40 of 51 localities sampled, 10 containing Potamopyrgus antipodarum, 23 Heleobia and 7 Potamolithus. Based on these results and previously published data, the known distribution of the mudsnail in Chile encompasses 6 hydrological basins, including 18 freshwater ecosystems. The finding of the mudsnails in several type localities of native species/subspecies of "Heleobia" that were not find in situ suggests species replacement or significant extinction of native fauna, a hypothesis supported by the restudy of type material that shows that endemic forms belong to the genus Potamolithus. This study shows the usefulness of integrative taxonomy not only resolving complex taxa with cryptic morphology but also measuring the extent of an ongoing invasion.

Global gene expression analysis provides insight into local adaptation to geothermal streams in tadpoles of the Andean toad Rhinella spinulosa.

The anuran Rhinella spinulosa is distributed along the Andes Range at altitudes that undergo wide daily and seasonal variation in temperature. One of the populations inhabits geothermal streams, a stable environment that influences life history traits such as the timing of metamorphosis. To investigate whether this population has undergone local adaptation to this unique habitat, we carried out transcriptome analyses in animals from two localities in two developmental stages (prometamorphic and metamorphic) and exposed them to two temperatures (20 and 25 °C). RNA-Seq, de novo assembly and annotation defined a transcriptome revealing 194,469 high quality SNPs, with 1,507 genes under positive selection. Comparisons among the experimental conditions yielded 1,593 differentially expressed genes. A bioinformatics search for candidates revealed a total of 70 genes that are highly likely to be implicated in the adaptive response of the population living in a stable environment, compared to those living in an environment with variable temperatures. Most importantly, the population inhabiting the geothermal environment showed decreased transcriptional plasticity and reduced genetic variation compared to its counterpart from the non-stable environment. This analysis will help to advance the understanding of the molecular mechanisms that account for the local adaptation to geothermal streams in anurans.

The complete mitochondrial genome of the Chilean endemic frog Telmatobius chusmisensis Formas, Cuevas & Nuñez, 2006 (Anura, Telmatobiidae).

Telmatobius chusmisensis is an endemic frog of northern Chile that is only known at its type locality, Chusmisa. In this study, the complete mitochondrial genome of Telmatobius chusmisensis was assembled using high-throughput sequencing data, yielding a circular genome of 19 312 bp with a nucleotide composition of A = 30.8%, C = 24.4%, G = 13.6% and T = 31.2%. Its gene composition and structure were similar to other anuran genomes available: 13 protein-coding genes, two rRNA genes, 22 tRNA genes and the D-loop region. Phylogenetic analysis using Bayesian inference (BI) and maximum likelihood (ML) showed that Telmatobius chusmisensis, T. bolivianus and T. vellardi are a highly supported monophyletic group. This genome information will allow us to gain a better understanding into phylogenetic and phylogeographic relationships in the genus Telmatobius.

Genes encoding novel secreted and transmembrane proteins are temporally and spatially regulated during Drosophila melanogaster embryogenesis.

BACKGROUND: Morphogenetic events that shape the Drosophila melanogaster embryo are tightly controlled by a genetic program in which specific sets of genes are up-regulated. We used a suppressive subtractive hybridization procedure to identify a group of developmentally regulated genes during early stages of D. melanogaster embryogenesis. We studied the spatiotemporal activity of these genes in five different intervals covering 12 stages of embryogenesis. RESULTS: Microarrays were constructed to confirm induction of expression and to determine the temporal profile of isolated subtracted cDNAs during embryo development. We identified a set of 118 genes whose expression levels increased significantly in at least one developmental interval compared with a reference interval. Of these genes, 53% had a phenotype and/or molecular function reported in the literature, whereas 47% were essentially uncharacterized. Clustering analysis revealed demarcated transcript groups with maximum gene activity at distinct developmental intervals. In situ hybridization assays were carried out on 23 uncharacterized genes, 15 of which proved to have spatiotemporally restricted expression patterns. Among these 15 uncharacterized genes, 13 were found to encode putative secreted and transmembrane proteins. For three of them we validated our protein sequence predictions by expressing their cDNAs in Drosophila S2R+ cells and analyzed the subcellular distribution of recombinant proteins. We then focused on the functional characterization of the gene CG6234. Inhibition of CG6234 by RNA interference resulted in morphological defects in embryos, suggesting the involvement of this gene in germ band retraction. CONCLUSION: Our data have yielded a list of developmentally regulated D. melanogaster genes and their expression profiles during embryogenesis and provide new information on the spatiotemporal expression patterns of several uncharacterized genes. In particular, we recovered a substantial number of unknown genes encoding putative secreted and transmembrane proteins, suggesting new components of signaling pathways that might be incorporated within the existing regulatory networks controlling D. melanogaster embryogenesis. These genes are also good candidates for additional targeted functional analyses similar to those we conducted for CG6234.See related minireview by Vichas and Zallen: http://www.jbiol.com/content/8/8/76.

Molecular characterization of a novel patched-related protein in Apis mellifera and Drosophila melanogaster.

The molecular identification and characterization of the patched-related (ptr) gene and protein in Apis mellifera and Drosophila melanogaster are reported. Ptr proteins are closely related in predicted topology and domain organization to the protein encoded by the Drosophila segment polarity gene patched. Ptrs have 12 potential transmembrane domains arranged in two sets of 1+5 membrane-spanning segments containing a conserved sterol-sensing domain (SSD) and functional GxxxD and PPXY motifs. Phylogenetic analysis showed that Ptrs belong to a previously uncharacterized class of insect proteins that share a high level of sequence identity. Analysis using quantitative real-time polymerase chain reaction (qPCR) indicates that ptr gene is preferentially expressed during embryo stages of A. mellifera development; interestingly, this pattern of temporal expression was also observed for the D. melanogaster homologue, suggesting that these proteins might be involved in embryo morphogenesis. To understand Ptr function at the molecular level, we investigated the subcellular distribution of DmPtr. We have shown by biochemical analysis that DmPtr protein is tightly associated with membranes. Consistently, Ptr immunoreactivity appears to be localized at the sites of membrane furrow formation during cellularization of D. melanogaster embryos. These studies indicated that Ptrs belong to a previously uncharacterized class of insect transmembrane proteins that share a high level of sequence identity. Our analysis of ptr gene expression and protein localization suggest that Ptr might fulfil a developmental role by participating in processes that require growth and stabilization of plasma membrane.

Increased adipogenesis of osteoporotic human-mesenchymal stem cells (MSCs) characterizes by impaired leptin action.

The bone marrow contains mesenchymal stem cells (MSCs) that differentiate to the osteogenic and adipogenic lineages. The fact that the decrease in bone volume of age-related osteoporosis is accompanied by an increase in marrow adipose tissue implies the importance that the adipogenic process may have in bone loss. We previously observed that MSCs from control and osteoporotic women showed differences in their capacity to differentiate into the osteogenic and adipogenic pathways. In vitro studies indicate that bone marrow stromal cells are responsive to leptin, which increases their proliferation, differentiation to osteoblasts, and the number of mineralized nodules, but inhibits their differentiation to adipocytes. The aim of the present report was to study the direct effect of leptin on control and osteoporotic MSCs analyzing whether the protective effect of leptin against osteoporosis could be expressed by inhibition of adipocyte differentiation. MSCs from control, and osteoporotic donors were subjected to adipogenic conditions, in the absence or in the presence of 62.5 nM leptin. The number of adipocytes, the content of PPARgamma protein, and mRNA, and leptin mRNA were measured by flow cytometry, Western blot, and RT-PCR, respectively. Results indicate that control and osteoporotic MSCs differ in their adipogenic potential as shown by expression of active PPARgamma protein. Leptin exerted an antiadipogenic effect only on control MSCs increasing the proportion of inactive phosphorylated PPARgamma protein. Finally, results obtained during adipogenesis of osteoporotic cells suggest that this process is abnormal not only because of increased adipocyte number, but because of impaired leptin cells response.