Cryptic Speciation in Brazilian Epiperipatus (Onychophora: Peripatidae) Reveals an Underestimated Diversity among the Peripatid Velvet Worms

Taxonomical studies of the neotropical Peripatidae (Onychophora, velvet worms) have proven difficult, due to intraspecific variation and uniformity of morphological characters across this onychophoran subgroup. We therefore used molecular approaches, in addition to morphological methods, to explore the diversity of Epiperipatus from the Minas Gerais State of Brazil.Our analyses revealed three new species. While Epiperipatus diadenoproctussp. nov. can be distinguished from E. adenocryptussp. nov. and E. paurognostussp. nov. based on morphology and specific nucleotide positions in the mitochondrial cytochrome c oxidase subunit I (COI) and small ribosomal subunit RNA gene sequences (12S rRNA), anatomical differences between the two latter species are not evident. However, our phylogenetic analyses of molecular data suggest that they are cryptic species, with high Bayesian posterior probabilities and bootstrap and Bremer support values for each species clade. The sister group relationship of E. adenocryptussp. nov. and E. paurognostussp. nov. in our analyses correlates with the remarkable morphological similarity of these two species. To assess the species status of the new species, we performed a statistical parsimony network analysis based on 582 base pairs of the COI gene in our specimens, with the connection probability set to 95%. Our findings revealed no connections between groups of haplotypes, which have been recognized as allopatric lineages in our phylogenetic analyses, thus supporting our suggestion that they are separate species.Our findings suggest high cryptic species diversity and endemism among the neotropical Peripatidae and demonstrate that the combination of morphological and molecular approaches is helpful for clarifying the taxonomy and species diversity of this apparently large and diverse onychophoran group

Diabetic retinopathy: current and future methods for early screening from a retinal hemodynamic and geometric approach

Diabetic retinopathy (DR) is a major disease and is the number one cause of blindness in the UK. In England alone, 4200 new cases appear every year and 1280 lead to blindness. DR is a result of diabetes mellitus, which affects the retina of the eye and specifically the vessel structure. Elevated levels of glucose cause a malfunction in the cell structure, which affects the vessel wall and, in severe conditions, leads to their breakage. Much research has been carried out on detecting the different stages of DR but not enough versatile research has been carried out on the detection of early DR before the appearance of any lesions. In this review, the authors approach the topic from the functional side of the human eye and how hemodynamic factors that are impaired by diabetes affect the vascular structur

Operons

Operons (clusters of co-regulated genes with related functions) are common features of bacterial genomes. More recently, functional gene clustering has been reported in eukaryotes, from yeasts to filamentous fungi, plants, and animals. Gene clusters can consist of paralogous genes that have most likely arisen by gene duplication. However, there are now many examples of eukaryotic gene clusters that contain functionally related but non-homologous genes and that represent functional gene organizations with operon-like features (physical clustering and co-regulation). These include gene clusters for use of different carbon and nitrogen sources in yeasts, for production of antibiotics, toxins, and virulence determinants in filamentous fungi, for production of defense compounds in plants, and for innate and adaptive immunity in animals (the major histocompatibility locus). The aim of this article is to review features of functional gene clusters in prokaryotes and eukaryotes and the significance of clustering for effective function

Explaining the host-finding behavior of blood-sucking insects: computerized simulation of the effects of habitat geometry on tsetse fly movement

BACKGROUND: Male and female tsetse flies feed exclusively on vertebrate blood. While doing so they can transmit the diseases of sleeping sickness in humans and nagana in domestic stock. Knowledge of the host-orientated behavior of tsetse is important in designing bait methods of sampling and controlling the flies, and in understanding the epidemiology of the diseases. For this we must explain several puzzling distinctions in the behavior of the different sexes and species of tsetse. For example, why is it that the species occupying savannahs, unlike those of riverine habitats, appear strongly responsive to odor, rely mainly on large hosts, are repelled by humans, and are often shy of alighting on baits? METHODOLOGY/PRINCIPLE FINDINGS: A deterministic model that simulated fly mobility and host-finding success suggested that the behavioral distinctions between riverine, savannah and forest tsetse are due largely to habitat size and shape, and the extent to which dense bushes limit occupiable space within the habitats. These factors seemed effective primarily because they affect the daily displacement of tsetse, reducing it by up to ,70%. Sex differences in behavior are explicable by females being larger and more mobile than males. CONCLUSION/SIGNIFICANCE: Habitat geometry and fly size provide a framework that can unify much of the behavior of all sexes and species of tsetse everywhere. The general expectation is that relatively immobile insects in restricted habitats tend to be less responsive to host odors and more catholic in their diet. This has profound implications for the optimization of bait technology for tsetse, mosquitoes, black flies and tabanids, and for the epidemiology of the diseases they transmit

Mobile Java Objects

In this paper we discuss the engineering requirements for adding object mobility to the Java programming language, and give an overview of the design and implementation of our mobile object system. We show that it is helpful to cluster objects for mobility, and that if these clusters represent untrusted pieces of code (for example Agents) then they must be encapsulated both to control their access and to control access to them. We show that managing large numbers of mobile objects in an open environment is a difficult problem, but has its roots in the management of large distributed name spaces. We propose an architecture for relocating moved objects that is both scaleable and tuneable. The mobile object system we describe has been implemented, and is currently in use as part of an ESPRIT agent project. We are currently evolving the design and implementation to provide additional security and distribution facilities

Body composition in children with type 1 diabetes in the first year after diagnosis: relationship to glycaemic control and cardiovascular risk

INTRODUCTION: Rapid weight gain is often observed following initiation of insulin therapy in children with type 1 diabetes mellitus (T1DM) and girls are particularly at risk of becoming overweight. The authors evaluated body composition changes in children during the first year after diagnosis and related this to markers of cardiovascular risk. METHODS: Body mass index (BMI) and body composition measured by whole body dual energy x-ray absorptiometry (DEXA) were assessed in 30 patients (18 boys) with T1DM 3-10 days after diagnosis, 6 weeks later and at 1 year, and on two occasions 1 year apart in 14 controls (8 boys). Cardiovascular risk markers were assessed in T1DM subjects at 1 year. RESULTS: T1DM subjects had lower BMI SD scores (SDS) at diagnosis than controls (mean (SD) BMI SDS -0.67 (1.34) vs 0.20 (1.14), p<0.05) and reduced percentage body fat (20.3% (4.6) vs 24.5% (7.7), p<0.05). T1DM subjects normalised their body composition at 6 weeks and this was maintained 1 year later. Girls with diabetes were thinner than boys at diagnosis (BMI SDS -1.64 (1.02) vs -0.02 (1.17), p<0.05) and at 1 year (BMI SDS -0.58(0.9) vs 0.65 (0.98), p<0.05). Girls had higher glycated haemoglobin (HbA1c) (8.8% (1.2) vs 7.8% (1.0), p<0.05), insulin dose (1.01 (0.30) vs 0.82 (0.18) U/kg/day, p=0.04), total cholesterol (4.30 (0.45) vs 3.79 (0.50) mmol/l, p<0.05) and high-density lipoprotein (2.62 (0.53) vs 2.02 (0.37) mmol/l). High sensitivity C reactive protein and fibrinogen were in the normal range and there were no differences between genders. DISCUSSION: Insulin deficiency at diagnosis of diabetes causes a catabolic state that is predominantly lipolytic. Body composition normalises within 6 weeks of treatment, though girls remain thinner than boys both at diagnosis and 1 year thereafter, in contrast to published findings. Despite girls being prescribed a larger insulin dose, their HbA1c and cholesterol levels are higher at 1 year suggesting increased insulin resistance and cardiovascular risk

Cell volume regulation: the role of taurine loss in maintaining membrane potential and cell pH

In response to a hyposmotic stress cells undergo a regulatory volume decrease (RVD) by losing osmotically active solutes and obliged water. During RVD, trout red cells lost taurine, K+ and Cl− but gained Na+ and Cl−. Over the full time course of RVD the chloride concentration in the cell water remained remarkably constant. Thus membrane potential and cell pH, which depends on the ratio of internal to external chloride concentration ([Cl−]i:[Cl−]o), remained fixed.When cell volume decreases it is only possible to keep the chloride concentration in the cell water constant if an equal percentage of the cell chloride pool and of the cell water pool are lost simultaneously. Quantitative analysis of our data showed that this requirement was fulfilled because, over the full time course of RVD, cells lost osmotically active solutes with a constant stoichiometry: 1 Cl−:1 positive charge:2.35 taurine. Any change in taurine permeability, by modifying the stoichiometric relationship, would affect the amount of water lost and consequently cell chloride concentration.Experiments carried out with different cations as substitutes for external Na+ suggest that the constancy of the chloride concentration is not finely tuned by some mechanism able to modulate the channel transport capacity, but results in part from the fact that the swelling-dependent channel constitutively possesses an adequately fixed relative permeability for cations and taurine. However, as a significant fraction of K+ and Cl− loss occurs via a KCl cotransporter, the contribution of the cotransport to the stochiometric relationship remains to be defined.The large amount of taurine released during RVD (50 % of all solutes) was shown to be transported as an electroneutral zwitterion and not as an anion. How the channel can accommodate the zwitterionic form of taurine, which possesses a high electrical dipole, is considered