Effect of thyroid hormone concentration on the transcriptional response underlying induced metamorphosis in the Mexican axolotl (Ambystoma)

<p>Abstract</p> <p>Background</p> <p>Thyroid hormones (TH) induce gene expression programs that orchestrate amphibian metamorphosis. In contrast to anurans, many salamanders do not undergo metamorphosis in nature. However, they can be induced to undergo metamorphosis via exposure to thyroxine (T₄). We induced metamorphosis in juvenile Mexican axolotls (<it>Ambystoma mexicanum</it>) using 5 and 50 nM T₄, collected epidermal tissue from the head at four time points (Days 0, 2, 12, 28), and used microarray analysis to quantify mRNA abundances.</p> <p>Results</p> <p>Individuals reared in the higher T₄concentration initiated morphological and transcriptional changes earlier and completed metamorphosis by Day 28. In contrast, initiation of metamorphosis was delayed in the lower T₄concentration and none of the individuals completed metamorphosis by Day 28. We identified 402 genes that were statistically differentially expressed by ≥ two-fold between T₄treatments at one or more non-Day 0 sampling times. To complement this analysis, we used linear and quadratic regression to identify 542 and 709 genes that were differentially expressed by ≥ two-fold in the 5 and 50 nM T₄treatments, respectively.</p> <p>Conclusion</p> <p>We found that T₄concentration affected the timing of gene expression and the shape of temporal gene expression profiles. However, essentially all of the identified genes were similarly affected by 5 and 50 nM T₄. We discuss genes and biological processes that appear to be common to salamander and anuran metamorphosis, and also highlight clear transcriptional differences. Our results show that gene expression in axolotls is diverse and precise, and that axolotls provide new insights about amphibian metamorphosis.</p

Evaluation of different custom angulated elastic glass fibre post on fracture resistance of maxillary central incisor: an in vitro study.

Background: Restoring Endodontically treated teeth (ETT) can be challenging for most dentists, particularly when a significant tooth structure is lost. Depending on the coronal tooth structure remaining and the technique used (direct or indirect), endodontic anchorage can involve either a cast post and core or a prefabricated post. Aim: This study aimed to investigate the effect of different custom angulated, i.e.,0°,5°,10°,15° elastic glass fibre post (Everstick post) on fracture resistance of maxillary central incisors. Materials and methods:  A total of forty-eight single-rooted maxillary central incisors were selected. All the samples were decoronated 2mm above the CEJ and endodontically treated. Post-space preparation was done for all the samples using peesoreamers ranging in size from 1-3.  The samples were then randomly divided into four groups (n=12) based on the different angulations, i.e., the angle between the core and the long axis of the root, with 0°, 5°, 10°, and 15° angulations, respectively. The fit of each post in the root canal was verified. Before cementation, the coronal part of each post was bent according to their respective groups. Dual-cure resin cement was used for luting the posts and cured subsequently. The fracture resistance of all the samples was evaluated using the universal testing machine after they were mounted in self-cure acrylic resin blocks. The data were analysed using One- way ANOVA and Tukey’s post-hoc test. Results: Group I exhibited the highest mean fracture resistance compared to other groups. However, One-way ANOVA showed no significant differences (p=0.161) between the four groups. Conclusion: Everstick fibre posts are a preferable alternative for maxillary central incisors with core angulations up to 15° between coronal and radicular segments as they provide better fracture resistance with a more favourable stress distribution

Effect of thyroid hormone concentration on the transcriptional response underlying induced metamorphosis in the Mexican axolotl (\u3ci\u3eAmbystoma\u3c/i\u3e)

Background Thyroid hormones (TH) induce gene expression programs that orchestrate amphibian metamorphosis. In contrast to anurans, many salamanders do not undergo metamorphosis in nature. However, they can be induced to undergo metamorphosis via exposure to thyroxine (T4). We induced metamorphosis in juvenile Mexican axolotls (Ambystoma mexicanum) using 5 and 50 nM T4, collected epidermal tissue from the head at four time points (Days 0, 2, 12, 28), and used microarray analysis to quantify mRNA abundances. Results Individuals reared in the higher T4 concentration initiated morphological and transcriptional changes earlier and completed metamorphosis by Day 28. In contrast, initiation of metamorphosis was delayed in the lower T4 concentration and none of the individuals completed metamorphosis by Day 28. We identified 402 genes that were statistically differentially expressed by ≥ two-fold between T4 treatments at one or more non-Day 0 sampling times. To complement this analysis, we used linear and quadratic regression to identify 542 and 709 genes that were differentially expressed by ≥ two-fold in the 5 and 50 nM T4 treatments, respectively. Conclusion We found that T4 concentration affected the timing of gene expression and the shape of temporal gene expression profiles. However, essentially all of the identified genes were similarly affected by 5 and 50 nM T4. We discuss genes and biological processes that appear to be common to salamander and anuran metamorphosis, and also highlight clear transcriptional differences. Our results show that gene expression in axolotls is diverse and precise, and that axolotls provide new insights about amphibian metamorphosis

Iterative Multi-granular Image Editing using Diffusion Models

Recent advances in text-guided image synthesis has dramatically changed how creative professionals generate artistic and aesthetically pleasing visual assets. To fully support such creative endeavors, the process should possess the ability to: 1) iteratively edit the generations and 2) control the spatial reach of desired changes (global, local or anything in between). We formalize this pragmatic problem setting as Iterative Multi-granular Editing. While there has been substantial progress with diffusion-based models for image synthesis and editing, they are all one shot (i.e., no iterative editing capabilities) and do not naturally yield multi-granular control (i.e., covering the full spectrum of local-to-global edits). To overcome these drawbacks, we propose EMILIE: Iterative Multi-granular Image Editor. EMILIE introduces a novel latent iteration strategy, which re-purposes a pre-trained diffusion model to facilitate iterative editing. This is complemented by a gradient control operation for multi-granular control. We introduce a new benchmark dataset to evaluate our newly proposed setting. We conduct exhaustive quantitatively and qualitatively evaluation against recent state-of-the-art approaches adapted to our task, to being out the mettle of EMILIE. We hope our work would attract attention to this newly identified, pragmatic problem setting.Comment: Pre-prin

2,4,6,8-Tetra­kis(4-ethyl­phen­yl)-3,7-diaza­bicyclo­[3.3.1]nonan-9-one

The bicyclo­[3.3.1]nonane ring in the title compound, C39H44N2O, adopts a chair–boat conformation with the four benzene rings being directed away from the carbonyl group. The presence of C—H⋯O contacts leads to helical supra­molecular chains along the b axis

Sal-Site: Integrating new and existing ambystomatid salamander research and informational resources

Salamanders of the genus Ambystoma are a unique model organism system because they enable natural history and biomedical research in the laboratory or field. We developed Sal-Site to integrate new and existing ambystomatid salamander research resources in support of this model system. Sal-Site hosts six important resources: 1) Salamander Genome Project: an information-based web-site describing progress in genome resource development, 2) Ambystoma EST Database: a database of manually edited and analyzed contigs assembled from ESTs that were collected from A. tigrinum tigrinum and A. mexicanum, 3) Ambystoma Gene Collection: a database containing full-length protein-coding sequences, 4) Ambystoma Map and Marker Collection: an image and database resource that shows the location of mapped markers on linkage groups, provides information about markers, and provides integrating links to Ambystoma EST Database and Ambystoma Gene Collection databases, 5) Ambystoma Genetic Stock Center: a website and collection of databases that describe an NSF funded salamander rearing facility that generates and distributes biological materials to researchers and educators throughout the world, and 6) Ambystoma Research Coordination Network: a web-site detailing current research projects and activities involving an international group of researchers. Sal-Site is accessible at

Feasible pathways for the multi-dimensional synthesis of carboxylic acid from benzo-pyrone methyl ketone

3-Acetyl coumarin derivatives are the key synthons to the numerous numbers of heterocyclic compound syntheses. Due to the wide spectrum applications of benzopyran derivatives in pharma, research, food technology and material science there is a multitude number of methodologies feasible to synthesize benzo pyrone heterocyclic derivatives. This article articulates the synthesis and molecular structure confirmation of oxidative product starting from methyl ketone compound by haloform reaction. Design of benign path ways for instance room temperature, reflux conditions and water bath mediated synthesis of desired compounds in expected yields is the foremost intent of the article. Solvent and catalyst optimization studies were carried to elevate the product yield and to precede the reaction in sustainable way. Furthermore compounds are confirmed by spectroscopic analytical methods such as 1HNMR, 13CNMR, IR and HRMS spectroscopy. This article paves the way to researchers to explore these analogues to explore disparate medicinal applications

From Biomedicine to Natural History Research: EST Resources for Ambystomatid Aalamanders

BACKGROUND: Establishing genomic resources for closely related species will provide comparative insights that are crucial for understanding diversity and variability at multiple levels of biological organization. We developed ESTs for Mexican axolotl (Ambystoma mexicanum) and Eastern tiger salamander (A. tigrinum tigrinum), species with deep and diverse research histories. RESULTS: Approximately 40,000 quality cDNA sequences were isolated for these species from various tissues, including regenerating limb and tail. These sequences and an existing set of 16,030 cDNA sequences for A. mexicanum were processed to yield 35,413 and 20,599 high quality ESTs for A. mexicanum and A. t. tigrinum, respectively. Because the A. t. tigrinum ESTs were obtained primarily from a normalized library, an approximately equal number of contigs were obtained for each species, with 21,091 unique contigs identified overall. The 10,592 contigs that showed significant similarity to sequences from the human RefSeq database reflected a diverse array of molecular functions and biological processes, with many corresponding to genes expressed during spinal cord injury in rat and fin regeneration in zebrafish. To demonstrate the utility of these EST resources, we searched databases to identify probes for regeneration research, characterized intra- and interspecific nucleotide polymorphism, saturated a human - Ambystoma synteny group with marker loci, and extended PCR primer sets designed for A. mexicanum / A. t. tigrinum orthologues to a related tiger salamander species. CONCLUSIONS: Our study highlights the value of developing resources in traditional model systems where the likelihood of information transfer to multiple, closely related taxa is high, thus simultaneously enabling both laboratory and natural history research