The role of family and environment in determining the skin bacterial communities of captive aquatic frogs, Xenopus laevis.

Skin microbes play an important role in amphibian tissue regeneration. Xenopus spp. (African clawed frogs) are well-established model organisms, and standard husbandry protocols, including use of antibiotics, may affect experimental outcomes by altering bacterial assemblages.

Knockdown of NeuroD2 leads to seizure-like behavior, brain neuronal hyperactivity and a leaky blood-brain barrier in a Xenopus laevis tadpole model of DEE75.

Developmental and Epileptic Encephalopathies (DEE) are a genetically diverse group of severe, early onset seizure disorders. DEE are normally identified clinically in the first six months of life by the presence of frequent, difficult to control seizures and accompanying stalling or regression of development. DEE75 results from de novo mutations of the NEUROD2 gene that result in loss of activity of the encoded transcription factor, and the seizure phenotype was shown to be recapitulated in Xenopus tropicalis tadpoles.

Characterisation and automated quantification of induced seizure-related behaviours in Xenopus laevis tadpoles.

Epilepsy, a clinical diagnosis characterised by paroxysmal episodes known as seizures, affects 1% of people worldwide. Safe and patient-specific treatment is vital and can be achieved by the development of rapid pre-clinical models of for identified epilepsy genes. Epilepsy can result from either brain injury or gene mutations, and can also be induced chemically.

Gene expression analysis of the Xenopus laevis early limb bud proximodistal axis.

Background: Limb buds develop as bilateral outgrowths of the lateral plate mesoderm and are patterned along three axes. Current models of proximal to distal patterning of early amniote limb buds suggest that two signals, a distal organizing signal from the apical epithelial ridge (AER, Fgfs) and an opposing proximal (retinoic acid [RA]) act early on pattern this axis.

Results: Transcriptional analysis of stage 51 Xenopus laevis hindlimb buds sectioned along the proximal-distal axis showed that the distal region is distinct from the rest of the limb.

Noggin proteins are multifunctional extracellular regulators of cell signaling.

Noggin is an extracellular cysteine knot protein that plays a crucial role in vertebrate dorsoventral patterning. Noggin binds and inhibits the activity of bone morphogenetic proteins via a conserved N-terminal clip domain. Noncanonical orthologs of Noggin that lack a clip domain ("Noggin-like" proteins) are encoded in many arthropod genomes and are thought to have evolved into receptor tyrosine kinase ligands that promote Torso/receptor tyrosine kinase signaling rather than inhibiting bone morphogenic protein signaling.

Manipulating the microbiome alters regenerative outcomes in Xenopus laevis tadpoles via lipopolysaccharide signalling.

Xenopus laevis tadpoles can regenerate functional tails, containing the spinal cord, notochord, muscle, fin, blood vessels and nerves, except for a brief refractory period at around 1 week of age. At this stage, amputation of the tadpole's tail may either result in scarless wound healing or the activation of a regeneration programme, which replaces the lost tissues. We recently demonstrated a link between bacterial lipopolysaccharides and successful tail regeneration in refractory stage tadpoles and proposed that this could result from lipopolysaccharides binding to Toll-like receptor 4 (TLR4).

Bacterial lipopolysaccharides can initiate regeneration of the tadpole tail.

Tadpoles of the frog can regenerate tails except for a short "refractory" period in which they heal rather than regenerate. Rapid and sustained production of ROS by NADPH oxidase (Nox) is critical for regeneration. Here, we show that tail amputation results in rapid, transient activation of the ROS-activated transcription factor NF-κB and expression of its direct target in the wound epithelium.

Characterization of deaths and therapeutic itineraries investigated by the Porto Alegre AIDS Mortality Committee, Brazil, in 2015.

Objective: to characterize AIDS deaths eligible for Porto Alegre AIDS Mortality Committee (AIDSMC) investigation, Brazil, in 2015, and their therapeutic itineraries.

Methods: this was a descriptive study using secondary data from surveillance information systems and AIDSMC investigation forms.

Results: out of 336 deaths from AIDS-related causes, 113 (33.

Bifurcation of Health Policy Regimes: A Study of Sleep Apnea Care and Benefits Coverage in Saskatchewan.

Background: A complex, poorly understood bifurcated health policy regime exists for Canada's First Nations people for extended health benefits coverage. This research adds to a small body of literature on the regime's impact on access and quality of care and its role in perpetuating health inequities in First Nations populations.

Methods: Using a case study of sleep apnea care in Saskatchewan, we identified issues of health service access and coverage through a literature review of extended benefits programs, legislation and policies and through 10 key informant interviews with federal and provincial extended benefit program administrators and sleep medicine physicians.

Exploring policy driven systemic inequities leading to differential access to care among Indigenous populations with obstructive sleep apnea in Canada.

Background: In settler societies such as Australia, Canada, New Zealand and the United States, health inequities drive lower health status and poorer health outcomes in Indigenous populations. This research unravels the dense complexity of how historical policy decisions in Canada can influence inequities in health care access in the 21(st) century through a case study on the diagnosis and treatment of obstructive sleep apnea (OSA). In Canada, historically rooted policy regimes determine current discrepancies in health care policy, and in turn, shape current health insurance coverage and physician decisions in terms of diagnosis and treatment of OSA, a clinical condition that is associated with considerable morbidity in Canada.

Gremlin1 induces anterior-posterior limb bifurcations in developing Xenopus limbs but does not enhance limb regeneration.

Gremlin1 (grem1) has been previously identified as being significantly up-regulated during regeneration of Xenopus laevis limbs. Grem1 is an antagonist of bone morphogenetic proteins (BMPs) with a known role in limb development in amniotes. It forms part of a self-regulating feedback loop linking epithelial (FGF) and mesenchymal (shh) signalling centres, thereby controlling outgrowth, anterior posterior and proximal distal patterning.

Xenopus Limb bud morphogenesis.

Xenopus laevis, the South African clawed frog, is a well-established model organism for the study of developmental biology and regeneration due to its many advantages for both classical and molecular studies of patterning and morphogenesis. While contemporary studies of limb development tend to focus on models developed from the study of chicken and mouse embryos, there are also many classical studies of limb development in frogs. These include both fate and specification maps, that, due to their age, are perhaps not as widely known or cited as they should be.

Distinct patterns of endosulfatase gene expression during Xenopus laevis limb development and regeneration.

The heparan sulfate 6-O-endosulfatases sulf1 and sulf2 regulate multiple cellular processes and organ development. Sulfs modulate a range of heparan-sulfate-dependent extracellular pathways, including the fibroblast growth factor, bone morphogenetic protein, and wingless/wnt signaling pathways. Known patterns of sulf transcript expression together with functional experiments have implicated the sulfs in chondrogenesis and muscle regeneration in mammals.

Development of the vertebrate tailbud.

The anatomical tailbud is a defining feature of all embryonic chordates, including vertebrates that do not end up with a morphological tail. Due to its seamless continuity with trunk tissues, the tailbud is often overlooked as a mere extension of the body axis; however, the formation of the tail from the tailbud undoubtedly involves unique and distinct mechanisms for forming axial tissues, such as the secondary neurulation process that generates the tailbud-derived spinal cord. Tailbud formation in the frog Xenopus laevis has been demonstrated to involve interaction of three posterior regions of the embryo that first come into alignment at the end of gastrulation, and molecular models for tailbud outgrowth and patterning have been proposed.

Viral epidemiology of respiratory infections among children at a tertiary hospital in Southern Brazil.

Introduction: This study reports the pediatric epidemiology of respiratory syncytial virus (RSV), influenza (IF), parainfluenza (PIV), and adenovirus (ADV) at Hospital de Clínicas de Porto Alegre.

Methods: Cases of infection, hospitalizations in intensive care units (ICUs), nosocomial infections, and lethality rates were collected from 2007 to 2010.

Results: RSV accounted for most nosocomial infections.

Distal expression of sprouty (spry) genes during Xenopus laevis limb development and regeneration.

The eukaryotic Sprouty (Spry) proteins are negative regulators of receptor tyrosine kinase signaling pathways, which in turn provide readout for morphogens such as fibroblast growth factors (Fgfs) that are essential for many developmental processes, including limb development. In a transcriptome analysis of early proximo-distal patterning of the Xenopus laevis limb bud, spry1a, 2 and 4 were predicted to be expressed predominantly in the distal third. Expression of all three in the distal limb initially corresponded to the progress zone mesenchyme, adjacent to the fgf8b-positive cryptic apical ectodermal ridge (AER).

Evaluation of respiratory syncytial virus group A and B genotypes among nosocomial and community-acquired pediatric infections in Southern Brazil.

Background: Respiratory syncytial virus (RSV) is the main cause of lower respiratory tract illness in children worldwide. Molecular analyses show two distinct RSV groups (A and B) that comprise different genotypes. This variability contributes to the capacity of RSV to cause yearly outbreaks.

Attenuation of bone morphogenetic protein signaling during amphibian limb development results in the generation of stage-specific defects.

The vertebrate limb is one of the most intensively studied organs in the field of developmental biology. Limb development in tetrapod vertebrates is highly conserved and dependent on the interaction of several important molecular pathways. The bone morphogenetic protein (BMP) signaling cascade is one of these pathways and has been shown to be crucial for several aspects of limb development.

Fundamental ratios and logarithmic periodicity in human limb bones.

Fundamental mathematical relationships are widespread in biology yet there is little information on this topic with regard to human limb bone lengths and none related to human limb bone volumes. Forty-six sets of ipsilateral upper and lower limb long bones and third digit short bones were imaged by computed tomography. Maximum bone lengths were measured manually and individual bone volumes calculated from computed tomography images using a stereologic method.

Studying regeneration in Xenopus.

For most Xenopus embryos, life is very short. The majority of research labs working with this model organism study the processes of early vertebrate patterning and morphogenesis. And quite rightly too, since over the last two decades labs across the world have provided the fate maps, animal cap assays, expression patterns, and functional screens that put Xenopus firmly on the map as a developmental model organism.

Histone deacetylases are required for amphibian tail and limb regeneration but not development.

Amphibians such as Xenopus laevis and Ambystoma mexicanum are capable of whole structure regeneration. However, transcriptional control over these events is not well understood. Here, we investigate the role of histone deacetylase (HDAC) enzymes in regeneration using HDAC inhibitors.

Optimization of one-step duplex real-time RT-PCR for detection of influenza and respiratory syncytial virus in nasopharyngeal aspirates.

Viruses are major contributors to acute respiratory infection-related morbidity and mortality worldwide. The influenza (IF) viruses and human respiratory syncytial virus (RSV) play a particularly important role in the etiology of acute respiratory infections. This study sought to standardize a one-step duplex real-time RT-PCR technique to optimize diagnosis of IFA/IFB and RSVA/RSVB infection.

Quantification of cell volume changes upon hyperosmotic stress in Saccharomyces cerevisiae.

Cell volume is a biophysical property, which is of great importance for quantitative characterisations of biological processes, such as osmotic adaptation. It also is a crucial parameter in the most common type of mathematical description of cellular behaviour-ordinary differential equation (ODE) models, e.g.