Project description:Plethodontid salamanders are the largest family of salamanders and are classic models for studying the effect of rapidly evolving courtship pheromones on mating behavior and reproductive success. Despite interests in plethodontid reproduction, very little is known about the molecular composition of salamander gametes, as the extraordinary sizes of their genomes have impaired the development of various omic-scale resources. To identify what proteins may be expressed in salamander sperm, we performed DIA-MS on sperm samples from two plethodontid species, Plethodon shermani and Desmognathus ocoee. As the first detailed study of salamander sperm, this study partially fills in a critical taxonomic gap in the study of fertilization proteins in vertebrates.
Project description:Tissue regeneration is widely distributed across the tree of life. Among vertebrates, salamanders possess an exceptional ability to regenerate amputated limbs and other complex structures. Thus far, molecular insights about limb regeneration have come from a relatively limited number of species from two closely related salamander families. To gain broader perspective on the molecular basis of limb regeneration and enhance the molecular toolkit of an emerging plethodontid salamander (Bolitoglossa ramosi), we used RNA-seq to generate transcript sequence data and identify 602 genes that are differentially expressed during limb regeneration. This list was further processed to identify a core set of genes that exhibit conserved expression changes between B. ramosi and the Mexican axolotl (Ambystoma mexicanum), and presumably their common ancestor approximately 180 million years ago. Our study highlights the importance of developing comparative gene expression data for studies of limb regeneration among salamanders. All animals used in this work were collected under the Contract on Genetic Access for scientific research for non commercial profit (Contrato de acceso a recursos genéticos para la investigación científica sin interés commercial) to Resources number 118–2015.
2018-09-26 | GSE105232 | GEO
Project description:Fine-scale ecological segregation between plethodontid salamanders in replicated contact zones
| PRJNA630450 | ENA
Project description:Effects of host species and environment on the skin microbiome of Plethodontid salamanders
| PRJNA387190 | ENA
Project description:Duplication and DNA loss in mitochondrial genome evolution of salamanders
Project description:Interventions: Group 1:Total fluid input = physiological requirement + preoperative cumulative loss + continuing loss + third space loss + compensatory volume expansion;Group 2:Goal-directed fluid therapy based on stroke volume variation;Group 3:Goal-directed fluid therapy based on stroke volume variation and plasma colloid osmotic pressure
Primary outcome(s): Indicators of changes in lung function;Postoperative pulmonary complications occurring within 7 days after surgery;Lung injury score
Study Design: Parallel
Project description:Tissue-specific differentiation programs become dysregulated during cancer evolution. The transcription factor Nkx2-1 is a master regulator of pulmonary differentiation that is downregulated in poorly differentiated lung adenocarcinoma. Here we use conditional murine genetics to study the fate of lung epithelial cells upon loss of their master cell fate regulator. Nkx2-1 deletion in normal and neoplastic lung causes not only loss of pulmonary identity but also gastric transdifferentiation. Nkx2-1 maintains pulmonary identity by sequestering the Foxa1 transcription factor at lung-specific loci and by inhibiting Foxa1 binding to gastrointestinal targets. Murine Nkx2-1-negative lung tumors mimic the mucinous subtype of human lung adenocarcinoma, which also exhibits gastric transdifferentiation. Nkx2-1-negative lung adenocarcinomas are dependent on the gastrointestinal gene Hnf4a for efficient initiation. Thus, loss of Nkx2-1 causes transdifferentiation rather than stable dedifferentiation in vivo, suggesting that inactivation of both active and latent differentiation programs are required for tumors to reach a primitive, dedifferentiated state. ChIP-seq data from murine lung adenocarcinomas on (i) transcription factors Nkx2-1 and Foxa in Nkx2-1-deleted tumors and Nkx2-1-positive control tumors, and (ii) four histone marks in Nkx2-1-deleted tumors and Nkx2-1-positive control tumors. (All samples in duplicate and with input controls, i.e. (2 x [(3+3) + (2+8)]) - 1 = 31 samples total - 1 input control used for transcription factor and histone mark, GSM1059357)
Project description:Study abstract: Axolotl salamanders (Ambystoma mexicanum) remain aquatic in their natural state, during which biomechanical forces on their diarthrodial limb joints are likely reduced relative to salamanders living on land. However, even as sexually mature adults, these amphibians can be induced to metamorphose into a weight-bearing terrestrial stage by environmental stress or the exogenous administration of thyroxine hormone. In some respects, this aquatic to terrestrial transition of axolotl salamanders through metamorphosis may model developmental and changing biomechanical skeletal forces in mammals during the prenatal to postnatal transition at birth and in the early postnatal period. To assess differences in the appendicular skeleton as a function of metamorphosis, anatomical and gene expression parameters were compared in skeletal tissues between aquatic and terrestrial axolotls that were the same age and genetically full siblings. The length of long bones and area of cuboidal bones in the appendicular skeleton, as well as the cellularity of cartilaginous and interzone tissues of femorotibial joints were generally higher in aquatic axolotls compared to their metamorphosed terrestrial siblings. A comparison of steady state mRNA transcripts encoding aggrecan core protein (ACAN), type II collagen (COL2A1), and growth and differentiation factor 5 (GDF5) in femorotibial cartilaginous and interzone tissues did not reveal any significant differences between aquatic and terrestrial axolotls. RNAseq samples: Total RNA was isolated from whole body tissue samples of Mexican axolotl salamanders (Ambystoma mexicanum) at the following developmental stages: Embryo at the tail bud stage, newly hatched larva, larva at the limb bud stage, juvenile at 8.5 centimeters, and adult using variations of guanidinium-based protocols. RNA quantity, purity, and integrity of both the individual samples and the resulting pool were determined with an Agilent 2100 Bioanalyzer using the Eukaryotic Total RNA nano series II analysis kit. The pooled RNA sample was poly-A selected and used for Illumina random priming directional library prep. Four lanes were sequenced only on one end providing single end reads and 4 lanes were sequenced at both ends giving paired-end reads. The library was sequenced on an Illumina HiSeq 2000 for 75bp reads producing 147,248,512 single end reads and 2 x 153,254,667 paired-end reads.