De novo genome assemblies of two cryptodiran turtles with ZZ/ZW and XX/XY sex chromosomes provide insights into patterns of genome reshuffling and uncover novel 3D genome folding in amniotes.

Understanding the evolution of chromatin conformation among species is fundamental to elucidate the architecture and plasticity of genomes. Nonrandom interactions of linearly distant loci regulate gene function in species-specific patterns, affecting genome function, evolution, and, ultimately, speciation. Yet, data from nonmodel organisms are scarce.

Evolution and dosage compensation of nucleolar organizing regions (NORs) mediated by mobile elements in turtles with female (ZZ/ZW) but not with male (XX/XY) heterogamety.

Understanding the evolution and regulation of nucleolar organizing regions (NORs) is important to elucidate genome structure and function. This is because ribosomal gene (rDNA) copy number and activity mediate protein biosynthesis, stress response, ageing, disease, dosage compensation and genome stability. Here, we found contrasting dosage compensation of sex-linked NORs in turtles with male and female heterogamety.

Karyotypic Evolution of Sauropsid Vertebrates Illuminated by Optical and Physical Mapping of the Painted Turtle and Slider Turtle Genomes.

Recent sequencing and software enhancements have advanced our understanding of the evolution of genomic structure and function, especially addressing novel evolutionary biology questions. Yet fragmentary turtle genome assemblies remain a challenge to fully decipher the genetic architecture of adaptive evolution. Here, we use optical mapping to improve the contiguity of the painted turtle () genome assembly and use fluorescent in situ hybridization (FISH) of bacterial artificial chromosome (BAC) clones, BAC-FISH, to physically map the genomes of the painted and slider turtles ().

Intramedullary fixation versus anatomically contoured plating of unstable ankle fractures: a randomized control trial.

Aim: This study compared functional outcomes between anatomical shaped fibular plates and intramedullary nail fixation of adult patients who sustained unstable ankle fractures.

Methods: A prospective randomized control trial was conducted between November 2013 and December 2016 on patients that presented with an unstable ankle fractures. They were randomized into a plate-and-screw group and a fibula nail group.

Lost to follow-up: Challenges to conducting orthopaedic research in South Africa.

Loss to follow-up poses a major problem for clinicians and researchers, and several factors that may increase its risk have been postulated. The objective of this study was to describe potential factors that contribute to loss to follow-up as seen in orthopaedic patients participating in a research study and attending the sole public orthopaedic service provider in the Northern Cape Province of South Africa (SA). All patients who underwent ankle fracture surgery at Kimberley Provincial Hospital between January 2012 and July 2013 were included, and the number of follow-up visits attended by each participant was recorded prospectively.

Cytogenetic Insights into the Evolution of Chromosomes and Sex Determination Reveal Striking Homology of Turtle Sex Chromosomes to Amphibian Autosomes.

Turtle karyotypes are highly conserved compared to other vertebrates; yet, variation in diploid number (2n = 26-68) reflects profound genomic reorganization, which correlates with evolutionary turnovers in sex determination. We evaluate the published literature and newly collected comparative cytogenetic data (G- and C-banding, 18S-NOR, and telomere-FISH mapping) from 13 species spanning 2n = 28-68 to revisit turtle genome evolution and sex determination. Interstitial telomeric sites were detected in multiple lineages that underwent diploid number and sex determination turnovers, suggesting chromosomal rearrangements.

Discovery of the youngest sex chromosomes reveals first case of convergent co-option of ancestral autosomes in turtles.

Most turtle species possess temperature-dependent sex determination (TSD), but genotypic sex determination (GSD) has evolved multiple times independently from the TSD ancestral condition. GSD in animals typically involves sex chromosomes, yet the sex chromosome system of only 9 out of 18 known GSD turtles has been characterized. Here, we combine comparative genome hybridization (CGH) and BAC clone fluorescent in situ hybridization (BAC FISH) to identify a macro-chromosome XX/XY system in the GSD wood turtle Glyptemys insculpta (GIN), the youngest known sex chromosomes in chelonians (8-20 My old).

Physical Mapping and Refinement of the Painted Turtle Genome (Chrysemys picta) Inform Amniote Genome Evolution and Challenge Turtle-Bird Chromosomal Conservation.

Comparative genomics continues illuminating amniote genome evolution, but for many lineages our understanding remains incomplete. Here, we refine the assembly (CPI 3.0.

Molecular cytogenetic search for cryptic sex chromosomes in painted turtles Chrysemys picta.

Sex determination is triggered by factors ranging from genotypic (GSD) to environmental (ESD), or both GSD + EE (GSD susceptible to environmental effects), and its evolution remains enigmatic. The presence/absence of sex chromosomes purportedly separates species at the ESD end of the continuum from the rest (GSD and GSD + EE) because the evolutionary dynamics of sex chromosomes and autosomes differ. However, studies suggest that turtles with temperature-dependent sex determination (TSD) are cryptically GSD and possess sex chromosomes.

The western painted turtle genome, a model for the evolution of extreme physiological adaptations in a slowly evolving lineage.

Background: We describe the genome of the western painted turtle, Chrysemys picta bellii, one of the most widespread, abundant, and well-studied turtles. We place the genome into a comparative evolutionary context, and focus on genomic features associated with tooth loss, immune function, longevity, sex differentiation and determination, and the species' physiological capacities to withstand extreme anoxia and tissue freezing.

Results: Our phylogenetic analyses confirm that turtles are the sister group to living archosaurs, and demonstrate an extraordinarily slow rate of sequence evolution in the painted turtle.

A ZZ/ZW microchromosome system in the spiny softshell turtle, Apalone spinifera, reveals an intriguing sex chromosome conservation in Trionychidae.

Reptiles display a wide diversity of sex-determining mechanisms ranging from temperature-dependent sex determination (TSD) to genotypic sex determination (GSD) with either male (XY) or female (ZW) heterogamety. Despite this astounding variability, the origin, structure, and evolution of sex chromosomes remain poorly understood. In turtles, TSD is purportedly ancestral while GSD arose multiple times independently.

Host cell/Orientia tsutsugamushi interactions: evolution and expression of syndecan-4 in Asian rodents (Rodentia, Muridae).

Scrub typhus is an acute febrile zoonotic disease and worldwide more than a billion people may be at risk for infection. Orientia tsutsugamushi, the causative agent of scrub typhus, is an obligate intracellular bacterium. Rodents are reported to be the primary reservoir hosts of the disease and according to the most recent surveys, all species within the Rattus sensu lato complex of the tribe Rattini are carriers of scrub typhus.

Karyotypic evolution of hapalomys inferred from chromosome painting: a detailed characterization contributing new insights into the ancestral murinae karyotype.

We report on the construction of a comparative chromosome map between the emblematic laboratory rat, Rattus norvegicus (RNO), and Delacour's Marmoset rat, Hapalomys delacouri (HDE), based on cross-species fluorescence in situ hybridization with R. norvegicus painting probes. Sixteen R.

Chromosomal evolution in Rattini (Muridae, Rodentia).

The Rattini (Muridae, Murinae) includes the biologically important model species Rattus norvegicus (RNO) and represents a group of rodents that are of clinical, agricultural and epidemiological importance. We present a comparative molecular cytogenetic investigation of ten Rattini species representative of the genera Maxomys, Leopoldamys, Niviventer, Berylmys, Bandicota and Rattus using chromosome banding, cross-species painting (Zoo-fluorescent in situ hybridization or FISH) and BAC-FISH mapping. Our results show that these taxa are characterised by slow to moderate rates of chromosome evolution that contrasts with the extensive chromosome restructuring identified in most other murid rodents, particularly the mouse lineage.

Impact of aldosterone receptor blockade on the deleterious cardiac effects of adrenergic activation in hypertensive rats.

Although in hypertension beta-adrenoreceptor activation promotes the transition from cardiac hypertrophy to pump dysfunction, the use of beta-blockers is controversial. As adrenergic activation may mediate adverse effects on the heart through the renin-angiotensin-aldosterone system, we evaluated the effects of the aldosterone receptor blocker, spironolactone (SPIRO), on isoproterenol (ISO)-induced changes in left ventricular cavity size and pump function and the determinants thereof in spontaneously hypertensive rats (SHR). ISO administered for 4.

The G-308A polymorphism of the TNF-alpha gene does not predict changes in cardiac function in response to medical therapy for idiopathic dilated cardiomyopathy.

The G-308A polymorphism of the tumour necrosis factor-alpha (TNF-alpha) gene, a variant that influences TNF-alpha transcription, may contribute to non-ischaemic dilated cardiomyopathy. To evaluate whether TNF-alpha genotyping may assist in identifying a subset of patients who could potentially benefit from immunomodulatory therapy, we assessed the relationship between the G-308A polymorphism of the TNF-alpha gene and changes in left ventricular (LV ) chamber dimensions and systolic function in patients with idiopathic dilated cardiomyopathy (IDC) before and six months after diuretic, digoxin and angiotensin-converting enzyme inhibitor (ACEI) therapy. In 331 patients with IDC and 349 controls, the TNF-2 (A) allele (odds ratio = 1.

Beta1- and alpha2c-adrenoreceptor variants as predictors of clinical aspects of dilated cardiomyopathy in people of African ancestry.

Background: Although the beta1-adrenoreceptor (AR) Gly389Arg and alpha2c-AR Del322-325 gene variants are associated with the response to beta-AR-blocker therapy, whether this effect is associated with the risk for heart failure, or the severity or progression of heart failure is uncertain.

Aims: To assess the relationship between Gly389Arg and Del322-325 variants and the presence, severity and progression of idiopathic dilated cardiomyopathy (IDC) in 403 black South African patients.

Methods: Genotypes were identified using a restriction fragment length polymorphism-based technique and automated sequencing.

Impact of beta2-adrenoreceptor gene variants on cardiac cavity size and systolic function in idiopathic dilated cardiomyopathy.

In heart failure, the Arg16Gly and Gln27Glu polymorphisms of the beta2-adrenoreceptor (beta2-AR) gene are associated with exercise-capacity, clinical outcomes and response to beta-AR blocker therapy. Whether beta2-AR gene variants mediate these effects in-part through an impact on cardiac structural remodeling and pump function independent of the effects of beta-blockers is uncertain. We evaluated whether the Arg16Gly and Gln27Glu variants of the beta2-AR gene predict left ventricular ejection fraction (LVEF) and LV end diastolic diameter (LVEDD) in patients with idiopathic dilated cardiomyopathy (IDC) before and 6 months after receiving standard medical therapy other than beta-AR blockers.

Functional variants of the angiotensinogen gene determine antihypertensive responses to angiotensin-converting enzyme inhibitors in subjects of African origin.

Objective: To determine whether the response to angiotensin-converting enzyme inhibitor (ACEI) monotherapy in subjects of African origin is determined by genetic variants within the angiotensinogen (AGT) gene.

Methods: A total of 194 hypertensive patients of African ancestry were recruited from district clinics in Johannesburg, South Africa. Eighty patients received open-label ACEI (enalapril or lisinopril) monotherapy, and 114 open-label calcium antagonist (nifedipine) as a drug class comparator.

Endotoxin-independent white cell cytokine production in haemodynamically stable patients with idiopathic dilated cardiomyopathy.

Introduction: In heart failure, increased circulating white cell tumour necrosis factor-alpha production could be attributed to elevated plasma endotoxin concentrations or an increase in white cell sensitivity to endotoxin.

Aims: To ascertain whether, in patients with IDC, circulating white cell TNF-alpha production is also mediated through endotoxin-independent mechanisms.

Methods: Whole blood production of TNF-alpha, both with and without the presence of an endotoxin stimulus, was evaluated in 89 controls and in 60 patients with IDC in New York Heart Association functional class I, II or III heart failure and without evidence of oedema, reduced peripheral perfusion or elevated plasma endotoxin concentrations.

Phosphodiesterase inhibition promotes the transition from compensated hypertrophy to cardiac dilatation in rats.

The cellular signaling pathways responsible for the transition from compensated left ventricular hypertrophy (LVH) to LV dilatation (remodeling) and heart failure are unclear. As chronic administration of a beta-adrenoreceptor (beta-AR) agonist mediates the premature onset of cardiac remodeling without myocyte necrosis or myocardial dysfunction in LVH, we suggest that beta-AR activation is critical in promoting the transition from compensated LVH to cardiac dilatation. However, beta-AR mediated effects in the heart can occur via either the cyclic adenosine monophosphate (cAMP) system or via cAMP independent signaling pathways.

Impact and mechanisms of action of neurotensin on cardiac contractility in the rat left ventricle.

Using immunoassay measurements, neurotensin was identified in rat ventricular tissue and in coronary effluent samples. Exogenous neurotensin evoked contractile responses in isolated ventricular preparations, which were equivalent in magnitude to those of norepinephrine and histamine, but greater than those for serotonin and angiotensin II. EC(50) values revealed neurotensin to be as potent as serotonin, but more potent than norepinephrine, histamine and angiotensin II.

Chronic beta-adrenoreceptor activation increases cardiac cavity size through chamber remodeling and not via modifications in myocardial material properties.

Chronic beta-adrenoreceptor (beta-AR) activation increases left ventricular (LV) cavity size by promoting a rightward shift in LV diastolic pressure-volume (P-V) relations in association with increases in low-tensile strength myocardial (non-cross-linked) collagen concentrations. Because diastolic P-V relations are determined by chamber remodeling as well as by myocardial material properties (indexed by myocardial stiffness), both of which are associated with modifications in myocardial collagen cross-linking, we evaluated whether chamber remodeling or alterations in myocardial material properties govern beta-AR-mediated modifications in diastolic P-V relations. The effects of chronic administration of isoproterenol (Iso; 0.

Therapy of ischemic cardiomyopathy with the immunomodulating agent pentoxifylline: results of a randomized study.

Background: Inflammatory immune activation commonly occurs in heart failure and may perpetuate this syndrome. We sought to determine whether the immunomodulating agent pentoxifylline enhances left ventricular function in patients with ischemic cardiomyopathy. We also investigated the effect of therapy on levels of brain natriuretic peptide (NT-pro BNP), C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-alpha), and the marker of apoptosis, Fas/Apo-1.