Host evolution shapes gut microbiome composition in .

The ecological and genetic changes that underlie the evolution of host-microbe interactions remain elusive, primarily due to challenges in disentangling the variables that alter microbiome composition. To understand the impact of host habitat, host genetics, and evolutionary history on microbial community structure, we examined gut microbiomes of river- and three cave-adapted morphotypes of the Mexican tetra, , in their natural environments and under controlled laboratory conditions. Field-collected samples were dominated by very few taxa and showed considerable interindividual variation.

Metabolic reprogramming underlies cavefish muscular endurance despite loss of muscle mass and contractility.

Physical inactivity is a scourge to human health, promoting metabolic disease and muscle wasting. Interestingly, multiple ecological niches have relaxed investment into physical activity, providing an evolutionary perspective into the effect of adaptive physical inactivity on tissue homeostasis. One such example, the Mexican cavefish has lost moderate-to-vigorous activity following cave colonization, reaching basal swim speeds ~3.

Discovery and characterization of H1-type proton channels in reef-building corals.

Voltage-dependent proton-permeable channels are membrane proteins mediating a number of important physiological functions. Here we report the presence of a gene encoding H1 voltage-dependent, proton-permeable channels in two species of reef-building corals. We performed a characterization of their biophysical properties and found that these channels are fast-activating and modulated by the pH gradient in a distinct manner.

The dynamics of epidermal stratification during post-larval development in zebrafish.

Background: The epidermis, as a defensive barrier, is a consistent trait throughout animal evolution. During post-larval development, the zebrafish epidermis thickens by stratification or addition of new cell layers. Epidermal basal stem cells, expressing the transcription factor p63, are known to be involved in this process.

Adaptation to low parasite abundance affects immune investment and immunopathological responses of cavefish.

Reduced parasitic infection rates in the developed world are suspected to underlie the rising prevalence of autoimmune disorders. However, the long-term evolutionary consequences of decreased parasite exposure on an immune system are not well understood. We used the Mexican tetra Astyanax mexicanus to understand how loss of parasite diversity influences the evolutionary trajectory of the vertebrate immune system, by comparing river with cave morphotypes.

Subterranean life: Behavior, metabolic, and some other adaptations of Astyanax cavefish.

The ability of fishes to adapt to any aquatic environment seems limitless. It is enthralling how new species keep appearing at the deep sea or in subterranean environments. There are close to 230 known species of cavefishes, still today the best-known cavefish is Astyanax mexicanus, a Characid that has become a model organism, and has been studied and scrutinized since 1936.

Comparative transcriptome analysis of wild and lab populations of Astyanax mexicanus uncovers differential effects of environment and morphotype on gene expression.

Studying how different genotypes respond to environmental variation is essential to understand the genetic basis of adaptation. The Mexican tetra, Astyanax mexicanus, has cave and surface-dwelling morphotypes that have adapted to entirely different environments in the wild, and are now successfully maintained in lab conditions. While this has enabled the identification of genetic adaptations underlying a variety of physiological processes, few studies have directly compared morphotypes between lab-reared and natural populations.

as a new marine model for evolutionary developmental biology.

Octopuses are intriguing organisms that, together with squids and cuttlefishes, form the extant coleoid cephalopods. This group includes many species that can potentially be used as models in the fields of biomedicine, developmental biology, evolution, neuroscience and even for robotics research. The purpose of this work is to first present a simple method for maintaining embryos under a laboratory setup.

The role of gene flow in rapid and repeated evolution of cave-related traits in Mexican tetra, Astyanax mexicanus.

Understanding the molecular basis of repeatedly evolved phenotypes can yield key insights into the evolutionary process. Quantifying gene flow between populations is especially important in interpreting mechanisms of repeated phenotypic evolution, and genomic analyses have revealed that admixture occurs more frequently between diverging lineages than previously thought. In this study, we resequenced 47 whole genomes of the Mexican tetra from three cave populations, two surface populations and outgroup samples.

Linking host morphology and symbiont performance in octocorals.

Octocorals represent an important group in reef communities throughout the tropical seas and, like scleractinian corals, they can be found in symbiosis with the dinoflagellate Symbiodinium. However, while there is extensive research on this symbiosis and its benefits in scleractinians, research on octocorals has focused so far mainly on the host without addressing their symbiosis. Here, we characterized and compared the photophysiological features of nine Caribbean octocoral species with different colony morphologies (sea fan, plumes, whips and rods) and related key morphological features with their respective symbiont photobiology.

CTCF knockout reveals an essential role for this protein during the zebrafish development.

Chromatin regulation and organization are essential processes that regulate gene activity. The CCCTC-binding factor (CTCF) is a protein with different and important molecular functions related with chromatin dynamics. It is conserved since invertebrates to vertebrates, posing it as a factor with an important role in the physiology.

Transit-Amplifying Cells in the Fast Lane from Stem Cells towards Differentiation.

Stem cells have a high potential to impact regenerative medicine. However, stem cells in adult tissues often proliferate at very slow rates. During development, stem cells may change first to a pluripotent and highly proliferative state, known as transit-amplifying cells.

DNA Damage Assessment in Zebrafish Embryos Exposed to Monceren(®) 250 SC Fungicide Using the Alkaline Comet Assay.

Monceren 250 SC is a commercial fungicide with the active ingredient 1-(4-chlorobenzyl)-1-(cyclopentyl)-3-phenylurea, also known as pencycuron. This compound inhibits the growth of fungi as Rhizoctonia solani that invades potato, rice, and cotton or as Pellicularia spp, which contaminates lettuce and tomato crops. In this study, we assessed genotoxicity or DNA damage by the alkaline comet assay in zebrafish blastula-stage embryos exposed to 250 to 1250 μg/mL of the Monceren fungicide or to Bleomycin (0.

Evolutionary Developmental Biology (Evo-Devo) Research in Latin America.

Famous for its blind cavefish and Darwin's finches, Latin America is home to some of the richest biodiversity hotspots of our planet. The Latin American fauna and flora inspired and captivated naturalists from the nineteenth and twentieth centuries, including such notable pioneers such as Fritz Müller, Florentino Ameghino, and Léon Croizat who made a significant contribution to the study of embryology and evolutionary thinking. But, what are the historical and present contributions of the Latin American scientific community to Evo-Devo? Here, we provide the first comprehensive overview of the Evo-Devo laboratories based in Latin America and describe current lines of research based on endemic species, focusing on body plans and patterning, systematics, physiology, computational modeling approaches, ecology, and domestication.

Zebrafish P54 RNA helicases are cytoplasmic granule residents that are required for development and stress resilience.

Stress granules are cytoplasmic foci that directly respond to the protein synthesis status of the cell. Various environmental insults, such as oxidative stress or extreme heat, block protein synthesis; consequently, mRNA will stall in translation, and stress granules will immediately form and become enriched with mRNAs. P54 DEAD box RNA helicases are components of RNA granules such as P-bodies and stress granules.

Zebrafish scarb2a insertional mutant reveals a novel function for the Scarb2/Limp2 receptor in notochord development.

Background: Scarb2 or Limp2 belong to a subfamily of Scavenger receptors described as lysosomal transmembrane glycosylated receptors, that are mutated in the human syndrome AMRF (action myoclonus-renal failure). The zebrafish insertional mutant scarb2a(hi1463Tg) has notochord defects, the notochord is a defining feature of chordates running along the center of the longitudinal axis and it is essential for forming the spinal column in all vertebrates.

Results: There are three paralogous scarb2 genes in zebrafish; scarb2a, scarb2b, and scarb2c.

A stem cell proliferation burst forms new layers of P63 expressing suprabasal cells during zebrafish postembryonic epidermal development.

Organ growth during development is a highly regulated process with both temporal and spatial constraints. Epidermal stratification is essential for skin growth and development. Although the zebrafish has been well studied, it is not known when and how epidermal stratification occurs.

The zebrafish mutants for the V-ATPase subunits d, ac45, E, H and c and their variable pigment dilution phenotype.

Background: The V-ATPase is a proton pump that creates an acidic medium, necessary for lysosome function and vesicular traffic. It is also essential for several developmental processes. Many enzymes, like the V-ATPase, are assemblies of multiple subunits, in which each one performs a specific function required to achieve full activity.

Germ cell survival in C. elegans and C. remanei is affected when the DEAD box RNA helicases VBH-1 or Cre-VBH-1 are silenced.

The Vasa family of proteins comprises several conserved DEAD box RNA helicases important for mRNA regulation whose exact function in the germline is still unknown. In Caenorhabditis elegans, there are six known members of the Vasa family, and all of them are associated with P granules. One of these proteins, VBH-1, is important for oogenesis, spermatogenesis, embryo development, and the oocyte/sperm switch in this nematode.

Bioinformatic analysis of P granule-related proteins: insights into germ granule evolution in nematodes.

Germ cells in many animals possess a specialized cytoplasm in the form of granules that contain RNA and protein complexes essential for the function and preservation of the germline. The mechanism for the formation of these granules is still poorly understood; however, the lack of conservation in their components across different species suggests evolutionary convergence in the assembly process. Germ granules are assumed to be present in all nematodes with a preformed germline.

Pigment dilution mutants from fish models with connection to lysosome-related organelles and vesicular traffic genes.

An interesting question in developmental biology is why mutations in genes with functions essential for the majority of cells produce diseases affecting only specific tissues. For example, pigment dilution disorders are often the consequence of mutations in conserved vesicular traffic genes. In Hermansky-Pudlak, Griscelli, and Chediak-Higashi pigment dilution syndromes, vesicular traffic mutations affect several organs with one characteristic in common: to carry out their functions they depend to a great extent on lysosome-related organelles (LROs), such as the melanosomes in melanocytes.

Freeze-crack technique to study epidermal development in zebrafish using differential interference contrast microscopy and fluorescent markers.

The zebrafish is a model organism used to study organogenesis during vertebrate development; however epidermis development has been the focus of only a few studies. Thus, new methodologies to highlight and study epidermal cells could be valuable to deepen our understanding of skin development. Large-scale mutagenic screenings have already identified many zebrafish mutants, which are models for human developmental diseases, however only four epidermis mutants have been isolated.

The DEAD box RNA helicase VBH-1 is required for germ cell function in C. elegans.

Vasa and Belle are conserved DEAD box RNA helicases required for germ cell function. Homologs of this group of proteins in several species, including mammals, are able to complement a mutation in yeast (DED1) suggesting that their function is highly conserved. It has been proposed that these proteins are required for mRNA translation regulation, but their specific mechanism of action is still unknown.