Chitobiose utilization in Borrelia burgdorferi is dually regulated by RpoD and RpoS

<p>Abstract</p> <p>Background</p> <p><it>Borrelia burgdorferi </it>has limited biosynthetic capabilities and must scavenge N-acetylglucosamine (GlcNAc), an essential component of the microbial cell wall, from the surrounding environment. Spirochetes cultured in the absence of free GlcNAc exhibit biphasic growth; however, addition of chitobiose (a dimer of GlcNAc) substitutes for free GlcNAc resulting in a single exponential phase. We evaluated the effect of RpoS and RpoN, the only alternative sigma factors in <it>B. burgdorferi</it>, on biphasic growth and chitobiose utilization in the absence of free GlcNAc. In addition, we investigated the source of GlcNAc in the second exponential phase.</p> <p>Results</p> <p>By comparing the growth of wild-type cells to insertional mutants for <it>rpoS </it>and <it>rpoN </it>we determined that RpoS, but not RpoN, partially regulates both biphasic growth and chitobiose utilization. The <it>rpoS </it>mutant, cultured in the absence of free GlcNAc, exhibited a significant delay in the ability to initiate a second exponential phase compared to the wild type and <it>rpoS </it>complemented mutant. Expression analysis of <it>chbC</it>, which encodes the membrane-spanning protein of the chitobiose phosphotransferase system, suggests the delay is due to the inability of the <it>rpoS </it>mutant to up regulate <it>chbC</it>. Furthermore, supplementing GlcNAc starved cultures with high concentrations (75 or 150 μM) of chitobiose resulted in biphasic growth of the <it>rpoS </it>mutant compared to a single exponential phase for the wild type and <it>rpoS </it>complemented mutant. In contrast, growth of the <it>rpoN </it>mutant under all conditions was similar to the wild type. 5' Rapid amplification of cDNA ends (5' RACE) revealed the transcriptional start site for <it>chbC </it>to be 42 bp upstream of the translational start site. Analysis of the <it>chbC </it>promoter region revealed homology to previously described RpoD and RpoS <it>B. burgdorferi </it>promoters. We also determined that yeastolate, a component of the growth medium (BSK-II), is not essential for second exponential phase growth.</p> <p>Conclusion</p> <p>Together these results suggest that RpoD and RpoS, but not RpoN, regulate biphasic growth and chitobiose utilization in <it>B. burgdorferi </it>by regulating the expression of the chitobiose transporter (<it>chbC</it>). The data also demonstrate that the second exponential phase observed in wild-type cells in the absence of free GlcNAc is not due to free chitobiose or GlcNAc oligomers present in the medium.</p

Insights into the Acadian orogeny, New England Appalachians: a provenance study of the Carrabassett and Kittery formations, Maine

The Central Maine Basin and Merrimack Trough are Silurian basins that formed adjacent to or were accreted to the Laurentian margin during the Acadian orogeny. The Early Devonian Carrabassett Formation of the Central Maine Basin and the Kittery Formation of the Merrimack Trough have major and trace element compositions indicative of a passive continental margin provenance, not unlike the older formations of the Central Maine Basin that are thought to have been derived from Laurentian sources. However, both the Carrabassett and Kittery formations have paleocurrent indicators of outboard sources. The Carrabassett Formation is one of the youngest formations of the Central Maine Basin and was deposited just prior to the Acadian orogeny. The Carrabassett and Kittery formations have major and trace element concentrations suggestive of passive margin turbidites derived from intermediate to felsic sources, inconsistent with a juvenile Avalonian provenance. The Carrabassett Formation contains detrital zircon grains that match the ages of peri-Gondwanan Ganderia. Unlike the dominance of positive bulk-rock εNd values that are characteristic of Avalonia, Ganderia has negative εNd values that are a better match for the negative εNd values of the Carrabassett and Kittery formations. However, Ganderia accreted to Laurentia during the Salinic orogeny, prior to the deposition of the Carrabassett Formation, and was basement to the sediments of the Central Maine Basin upon which the Carrabassett and other formations were deposited. Wedging of Ganderia by Avalonia during the initial stages of the Acadian orogeny may have uplifted Ganderia, forming highlands outboard of the Central Maine Basin that served as the source of the Carrabassett Formation sediments. RÉSUMÉ Le bassin central du Maine et la cuvette de Merrimack constituent des bassins siluriens s’étant formés le long de la marge laurentienne ou s’y étant accrétés au cours de l’orogenèse acadienne. La Formation du Dévonien précoce de Carrabassett, dans le bassin central du Maine, et la Formation de Kittery, de la cuvette de Merrimack, présentent des compositions en éléments majeurs et traces signalant une provenance d’une marge continentale passive, à l’instar des formations plus âgées du bassin central du Maine qu’on pense originaires de sources laurentiennes. Les formations de Carrabassett et de Kittery comportent toutefois des indicateurs de paléocourants de sources extérieures. La Formation de Carrabassett constitue l’une des formations les plus récentes du bassin central du Maine; elle s’est mise en place juste avant l’orogenèse acadienne. Les caractéristiques géochimiques et géochronologique des formations de Carrabassett et de Kittery pourraient par conséquent permettre l’identification du terrane de collision. Les formations de Carrabassett et de Kittery possèdent des concentrations d’éléments majeurs et traces évoquant les turbidites de marge passive en provenance de sources intermédiaires à felsiques, ce qui est contradictoire avec une origine avalonienne juvénile. La Formation de Carrabassett comporte des grains détritiques de zircon correspondant aux âges du Ganderia périgondwanien. Contrairement à la prédominance de concentrations εNd positives de roche en vrac caractéristiques d’Avalonia, Ganderia présentent des concentrations εNd négatives qui cadrent mieux avec les concentrations εNd négatives des formations de Carrabassett et de Kittery. Ganderia s’est toutefois accrété à Laurentia au cours de l’orogenèse salinique, avant le dépôt de la Formation de Carrabassett, et il a constitué le socle des sédiments du bassin central du Maine sur lesquels Carrabassett et d’autres formations se sont déposées. L’enfoncement d’Avalonia sous Ganderia au cours des stades initiaux de l’orogenèse acadienne pourrait avoir soulevé Ganderia, formant un massif à l’extérieur du bassin central du Maine qui a servi de source aux sédiments de la Formation de Carrabassett. [Traduit par la redaction

Subduction Initiation Recorded in the Dadeville Complex of Alabama and Georgia, Southeastern United States

The Dadeville Complex of Alabama and Georgia (southeastern United States) represents the largest suite of exposed mafic-ultramafic rocks in the southern Appalachians. Due to poor preservation, chemical alteration, and tectonic reworking, a specific tectonic origin for the Dadeville Complex has been difficult to deduce. We obtained new whole-rock and mineral geochemistry coupled with zircon U-Pb geochronology to investigate the magmatic and metamorphic processes recorded by the Dadeville Complex, as well as the timing of these processes. Our data reveal an up-stratigraphic evolution in the geochemistry of the volcanic rocks, from forearc basalts to boninites. Our new U-Pb zircon crystallization data—obtained from three amphibolite samples—place the timing of forearc/protoarc volcanism no later than ca. 467 Ma. New thermobarometry suggests that the Dadeville Complex rocks subsequently experienced deep, high-grade metamorphism, at pressure-temperature conditions of \u3e7 kbar and \u3e760 °C. The data presented here support a model for formation of the Dadeville Complex in the forearc region of a subduction zone during subduction initiation and protoarc development, followed by deep burial/underthrusting of the complex during orogenesis

Cortical Gyrification in Velo-Cardio-Facial (22q11.2 Deletion) Syndrome: A Longitudinal Study

Introduction: Velo-cardio-facial syndrome (VCFS) has been identified as an important risk factor for psychoses, with up to 32% of individuals with VCFS developing a psychotic illness. Individuals with VCFS thus form a unique group to identify and explore early symptoms and biological correlates of psychosis. In this study, we examined if cortical gyrification pattern, i.e. gyrification index (GI) can be a potential neurobiological marker for psychosis. Method: GIs of 91 individuals with VCFS were compared with 29 siblings and 54 controls. Further, 58 participants with VCFS, 21 siblings and 18 normal controls were followed up after 3 years and longitudinal changes in GI were compared. Additionally, we also correlated longitudinal changes in GI in individuals with VCFS with prodromal symptoms of psychosis on the Scale of Prodromal Symptoms (SOPS). Result: Individuals with VCFS had significantly lower GIs as compared to their siblings and normal controls. Longitudinal examination of GI did not reveal any significant group–time interactions between the three groups. Further, longitudinal change in GI scores in the VCFS group was negatively correlated with positive prodromal symptoms, with the left occipital region reaching statistical significance. Conclusion: The study confirms previous reports that individuals with VCFS have reduced cortical folding as compared to normal controls. However over a period of three years, there is no difference in the rate of change of GI among both individuals with VCFS and normal controls. Finally, our results suggest that neuroanatomical alterations in areas underlying visual processing may be an early marker for psychosis

Severity of parkinsonism associated with environmental manganese exposure

BACKGROUND: Exposure to occupational manganese (Mn) is associated with neurotoxic brain injury, manifesting primarily as parkinsonism. The association between environmental Mn exposure and parkinsonism is unclear. To characterize the association between environmental Mn exposure and parkinsonism, we performed population-based sampling of residents older than 40 in Meyerton, South Africa (N = 621) in residential settlements adjacent to a large Mn smelter and in a comparable non-exposed settlement in Ethembalethu, South Africa (N = 95) in 2016-2020. METHODS: A movement disorders specialist examined all participants using the Unified Parkinson Disease Rating Scale motor subsection part 3 (UPDRS3). Participants also completed an accelerometry-based kinematic test and a grooved pegboard test. We compared performance on the UPDRS3, grooved pegboard, and the accelerometry-based kinematic test between the settlements using linear regression, adjusting for covariates. We also measured airborne PM RESULTS: Mean PM CONCLUSIONS: Environmental airborne Mn exposures at levels substantially lower than current occupational exposure thresholds in the United States may be associated with clinical parkinsonism

Estrogen Receptor-α Mediates Diethylstilbestrol-Induced Feminization of the Seminal Vesicle in Male Mice

Background: Studies have shown that perinatal exposure to the synthetic estrogen diethylstilbestrol (DES) leads to feminization of the seminal vesicle (SV) in male mice, as illustrated by tissue hyperplasia, ectopic expression of the major estrogen-inducible uterine secretory protein lactoferrin (LF), and reduced expression of SV secretory protein IV (SVS IV)

Heart Development, Coronary Vascularization and Ventricular Maturation in a Giant Danio (Devario malabaricus)

Giant danios (genus Devario), like zebrafish, are teleosts belonging to the danioninae subfamily of cyprinids. Adult giant danios are used in a variety of investigations aimed at understanding cellular and physiological processes, including heart regeneration. Despite their importance, little is known about development and growth in giant danios, or their cardiac and coronary vessels development. To address this scarcity of knowledge, we performed a systematic study of a giant danio (Devario malabaricus), focusing on its cardiac development, from the segmentation period to ten months post-fertilization. Using light and scanning electron microscopy, we documented that its cardiovascular development and maturation proceed along well defined dynamic and conserved morphogenic patterns. The overall size and cardiovascular expansion of this species was significantly impacted by environmental parameters such as rearing densities. The coronary vasculature began to emerge in the late larval stage. More importantly, we documented two possible loci of initiation of the coronary vasculature in this species, and compared the emergence of the coronaries to that of zebrafish and gourami. This is the first comprehensive study of the cardiac growth in a Devario species, and our findings serve as an important reference for further investigations of cardiac biology using this species

Constraining the Composition of the Subcontinental Lithospheric Mantle Beneath the East African Rift: FTIR Analysis of Water in Spinel Peridotite Mantle Xenoliths

The East African Rift System was initiated by the impingement of the Afar mantle plume on the base of the non-cratonic continental lithosphere (assembled during the Pan-African Orogeny), producing over 300,000 kmof continental flood basalts approx.30 Ma ago. The contribution of the subcontinental lithospheric mantle (SCLM) to this voluminous period of volcanism is implied based on basaltic geochemical and isotopic data. However, the role of percolating melts on the SCLM composition is less clear. Metasomatism is capable of hybridizing or overprinting the geochemical signature of the SCLM. In addition, models suggest that adding fluids to lithospheric mantle affects its stability. We investigated the nature of the SCLM using Fourier transform infrared spectrometry (FTIR) to measure water content in mantle xenoliths entrained in young (1 Ma) basaltic lavas from the Ethiopian volcanic province. The mantle xenoliths consist dominantly of spinel lherzolites and are composed of nominally anhydrous minerals, which can contain trace water as H in mineral defects. Eleven mantle xenoliths come from the Injibara-Gojam region and two from the Mega-Sidamo region. Water abundances of olivines in six samples are 1-5ppm H2O while the rest are below the limit of detection (<0.5 ppm H2O); orthopyroxene and clinopyroxene contain 80-238 and 111-340 ppm wt H2O, respectively. Two xenoliths have higher water contents - a websterite (470 ppm) and dunite (229 ppm), consistent with involvement of ascending melts. The low water content of the upper SCLM beneath Ethiopia is as dry as the oceanic mantle except for small domains represented by percolating melts. Consequently, rifting of the East African lithosphere may not have been facilitated by a hydrated upper mantle

Consensus guidelines for improving quality of assessment and training for neuromuscular diseases

Critical components of successful evaluation of clinical outcome assessments (COAs) in multisite clinical trials and clinical practice are standardized training, administration, and documented reliability of scoring. Experiences of evaluators, alongside patient differences from regional standards of care, may contribute to heterogeneity in clinical center\u27s expertise. Achieving low variability and high reliability of COA is fundamental to clinical research and to give confidence in our ability to draw rational, interpretable conclusions from the data collected. The objective of this manuscript is to provide a framework to guide the learning process for COAs for use in clinics and clinical trials to maximize reliability and validity of COAs in neuromuscular disease (NMD). This is a consensus-based guideline with contributions from fourteen leading experts in clinical outcomes and the field of clinical outcome training in NMD. This framework should guide reliable and valid assessments in NMD specialty clinics and clinical trials. This consensus aims to expedite study start up with a progressive training pathway ranging from research naïve to highly experienced clinical evaluators. This document includes recommendations for education guidelines and roles and responsibilities of key stakeholders in COA assessment and implementation to ensure quality and consistency of outcome administration across different settings