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1.
Microb Ecol ; 76(4): 911-924, 2018 Nov.
Article in English | MEDLINE | ID: mdl-29663040

ABSTRACT

The role of fungi in metal cycling in acidic environments has been little explored to date. In this study, two acid-tolerant and metal-resistant Penicillium isolates, strains ShG4B and ShG4C, were isolated from a mine site in the Transbaikal area of Siberia (Russia). Waters at the mine site were characterized by extremely high metal concentrations: up to 18 g l-1 Fe and > 2 g l-1 each of Cu, Zn, Al, and As. Both isolates were identified as Penicillium spp. by phylogenetic analyses and they grew well in Czapek medium acidified to pH 2.5. Resistance to Cu, Cd, Ni, Co, and arsenate was in the range of 1-10 g l-1. Further experiments with Penicillium strain ShG4C demonstrated that growth in Cu-containing media was accompanied by the precipitation of Cu-oxalate (moolooite) and the formation of extracellular vesicles enriched in Cu on the mycelia. Vesicles were greatly reduced in size in Cd-containing media and were not formed in the presence of Ni or Co. Cd-oxalate was detected as a crystalline solid phase in Cd-exposed mycelia. Hydrated Ni-sulfate (retgersite) and Co-sulfate (bieberite) were detected in mycelia grown in the presence of Ni and Co, respectively. The results demonstrated that acid-tolerant and metal-resistant Penicillium constitute a component in extremophilic microbiomes, contributing to organic matter breakdown and formation of secondary solid phases at pH ranges found in acid rock drainage.


Subject(s)
Arsenic/metabolism , Metals, Heavy/metabolism , Penicillium/metabolism , Water Pollutants, Chemical/metabolism , Fungal Proteins/analysis , Penicillium/classification , Penicillium/genetics , Phylogeny , Siberia
2.
Antonie Van Leeuwenhoek ; 110(12): 1669-1679, 2017 Dec.
Article in English | MEDLINE | ID: mdl-28748290

ABSTRACT

Almost all the known isolates of acidophilic or acid-tolerant sulphate-reducing bacteria (SRB) belong to the spore-forming genus Desulfosporosinus in the Firmicutes. The objective of this study was to isolate acidophilic/acid-tolerant members of the genus Desulfovibrio belonging to deltaproteobacterial SRB. The sample material originated from microbial mat biomass submerged in mine water and was enriched for sulphate reducers by cultivation in anaerobic medium with lactate as an electron donor. A stirred tank bioreactor with the same medium composition was inoculated with the sulphidogenic enrichment. The bioreactor was operated with a temporal pH gradient, changing daily, from an initial pH of 7.3 to a final pH of 3.7. Among the bacteria in the bioreactor culture, Desulfovibrio was the only SRB group retrieved from the bioreactor consortium as observed by 16S rRNA-targeted denaturing gradient gel electrophoresis. Moderately acidophilic/acid-tolerant isolates belonged to Desulfovibrio aerotolerans-Desulfovibrio carbinophilus-Desulfovibrio magneticus and Desulfovibrio idahonensis-Desulfovibrio mexicanus clades within the genus Desulfovibrio. A moderately acidophilic strain, Desulfovibrio sp. VK (pH optimum 5.7) and acid-tolerant Desulfovibrio sp. ED (pH optimum 6.6) dominated in the bioreactor consortium at different time points and were isolated in pure culture.


Subject(s)
Adaptation, Biological , Bioreactors , Desulfovibrio/isolation & purification , Desulfovibrio/metabolism , Environmental Microbiology , Hydrogen-Ion Concentration , RNA, Ribosomal, 16S/genetics , Desulfovibrio/classification , Desulfovibrio/genetics , Mining , Phylogeny , Sequence Analysis, DNA , Water Microbiology
3.
Cochrane Database Syst Rev ; 1: CD009704, 2016 01 28.
Article in English | MEDLINE | ID: mdl-26816385

ABSTRACT

BACKGROUND: People with a serious mental illness are more likely to smoke more and to be more dependent smokers than the general population. This may be due to a wide range of factors that could include a common aetiology to both smoking and the illness, self medication, smoking to alleviate adverse effects of medications, boredom in the existing environment, or a combination of these factors. It is important to undertake this review to facilitate improvements in both the health and safety of people with serious mental illness who smoke, and to reduce the overall burden of costs (both financial and health) to the smoker and, eventually, to the taxpayer. OBJECTIVES: To review the effects of smoking cessation advice for people with serious mental illness. SEARCH METHODS: We searched the Cochrane Schizophrenia Group Specialized Trials Register up to 2 April 2015, which is based on regular searches of CENTRAL, BIOSIS, PubMed, MEDLINE, EMBASE, CINAHL, PsycINFO, and trial registries. We also undertook unsystematic searches of a sample of the component databases (BNI, CINHAL, EMBASE, MEDLINE, and PsycINFO), up to 2 April 2015, and searched references of all identified studies SELECTION CRITERIA: We planned to include all randomised controlled trials (RCTs) that focussed on smoking cessation advice versus standard care or comparing smoking cessation advice with other more focussed methods of delivering care or information. DATA COLLECTION AND ANALYSIS: The review authors (PK, AC, and DB) independently screened search results but did not identify any trials that fulfilled the inclusion criteria of this review. MAIN RESULTS: We did not identify any RCTs that evaluated advice regarding smoking cessation for people with serious mental illness. The excluded studies illustrate that randomisation of packages of care relevant to smokers with serious mental illness is possible. AUTHORS' CONCLUSIONS: People with serious mental illness are more likely to smoke than the general population. Yet we could not find any high quality evidence to guide the smoking cessation advice healthcare professionals pass onto service users. This is an area where trials are possible and needed.


Subject(s)
Counseling , Mental Disorders , Smoking Cessation , Humans
4.
Risk Anal ; 36(4): 742-55, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26133501

ABSTRACT

Adversarial risk analysis has been introduced as a framework to deal with risks derived from intentional actions of adversaries. The analysis supports one of the decisionmakers, who must forecast the actions of the other agents. Typically, this forecast must take account of random consequences resulting from the set of selected actions. The solution requires one to model the behavior of the opponents, which entails strategic thinking. The supported agent may face different kinds of opponents, who may use different rationality paradigms, for example, the opponent may behave randomly, or seek a Nash equilibrium, or perform level-k thinking, or use mirroring, or employ prospect theory, among many other possibilities. We describe the appropriate analysis for these situations, and also show how to model the uncertainty about the rationality paradigm used by the opponent through a Bayesian model averaging approach, enabling a fully decision-theoretic solution. We also show how as we observe an opponent's decision behavior, this approach allows learning about the validity of each of the rationality models used to predict his decision by computing the models' (posterior) probabilities, which can be understood as a measure of their validity. We focus on simultaneous decision making by two agents.

5.
Phys Chem Chem Phys ; 17(44): 29566-73, 2015 Nov 28.
Article in English | MEDLINE | ID: mdl-26457656

ABSTRACT

In order to enhance the electrical energy storage capabilities of nanostructured carbon materials, inter-particle spacer strategies are needed to maintain ion-accessible surface area between the nanoparticles. This paper presents a comparison between different classes of divalent, dinuclear coordination complexes which both show strong adsorption to SWCNTs and have molecular spacer properties that maintain electrochemical activity. We find that a novel, dinuclear zinc hydrazone complex binds as an ion-pair at very high loading while not inducing significant aggregation as compared to our previously studies of dinuclear ruthenium complexes. These conclusions are supported by conductivity and dispersion stability data. Moreover, since zinc is an earth abundant metal, these complexes can be used as components in sustainable energy storage materials. Binding kinetics and binding equilibrium data are presented. Modeling of the adsorption isotherm is best fit with the BET model. Kinetics data support an independent binding model. Preliminary capacitance and membrane resistance data are consistent with the complexes acting as molecular spacers between the SWCNTs in a condensed thin film.

6.
Virol J ; 11: 180, 2014 Oct 08.
Article in English | MEDLINE | ID: mdl-25297984

ABSTRACT

BACKGROUND: Retroviruses encode a very limited number of proteins and therefore must exploit a wide variety of host proteins for completion of their lifecycle. METHODS: We performed an insertional mutagenesis screen to identify novel cellular regulators of retroviral replication. RESULTS: This approach identified the ATP-dependent chromatin remodeler, chromodomain helicase DNA-binding protein 2 (CHD2), as well as the highly related CHD1 protein, as positive regulators of both MLV and HIV-1 replication in rodent and human cells. RNAi knockdown of either CHD2 or the related CHD1 protein, in human cells resulted in a block to infection by HIV-1, specifically at the level of transcription. CONCLUSIONS: These results demonstrate that CHD1 and CHD2 can act as positive regulators of HIV-1 gene expression.


Subject(s)
DNA Helicases/metabolism , DNA-Binding Proteins/metabolism , Gene Expression Regulation, Viral , HIV Infections/enzymology , HIV-1/genetics , DNA Helicases/genetics , DNA-Binding Proteins/genetics , HIV Infections/genetics , HIV Infections/virology , HIV-1/metabolism , Humans , Viral Proteins/genetics , Viral Proteins/metabolism
8.
Endocrinology ; 165(8)2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38984714

ABSTRACT

The blood-brain barrier (BBB) is an extensive capillary network that protects the brain from environmental and metabolic toxins while limiting drug delivery to the central nervous system (CNS). The ATP-binding cassette transporter breast cancer resistance protein (Bcrp) reduces drug delivery across the BBB by actively transporting its clinical substrates back into peripheral circulation before their entry into the CNS compartment. 17ß-Estradiol (E2)-elicited changes in Bcrp transport activity and expression have been documented previously. We report a novel signaling mechanism by which E2 decreases Bcrp transport activity in mouse brain capillaries via rapid nongenomic signaling through estrogen receptor α. We extended this finding to investigate the effects of different endocrine-disrupting compounds (EDCs) and selective estrogen receptor modulators (SERMs) on Bcrp transport function. We also demonstrate sex-dependent expression of Bcrp and E2-sensitive Bcrp transport activity at the BBB ex vivo. This work establishes an explanted tissue-based model by which to interrogate EDCs and SERMs as modulators of nongenomic estrogenic signaling with implications for sex and hormonal regulation of therapeutic delivery into the CNS.


Subject(s)
ATP Binding Cassette Transporter, Subfamily G, Member 2 , Blood-Brain Barrier , Estradiol , Estrogen Receptor alpha , Signal Transduction , Animals , Blood-Brain Barrier/metabolism , Blood-Brain Barrier/drug effects , ATP Binding Cassette Transporter, Subfamily G, Member 2/metabolism , Estrogen Receptor alpha/metabolism , Mice , Female , Signal Transduction/drug effects , Estradiol/pharmacology , Male , Biological Transport/drug effects , Mice, Inbred C57BL
9.
Teach Learn Med ; 25(3): 249-57, 2013.
Article in English | MEDLINE | ID: mdl-23848333

ABSTRACT

BACKGROUND: No standardized educational curriculum exists for pediatric sedation practitioners. We sought to describe the curriculum and implementation of a pediatric sedation provider course and assess learner satisfaction with the course curriculum. DESCRIPTION: The course content was determined by formulating a needs assessment using published sedation guidelines, reports of sedation related adverse events, and a survey of sedation practitioners. Students provided feedback regarding satisfaction with the course immediately following the course and 6 months later. EVALUATION: The course consisted of 5 didactic lectures, 1 small-group session, 6 simulation scenarios, a course syllabus, and a written examination. The course was conducted over 1 day at 3 different locations. Sixty-nine students completed the course and were uniformly satisfied with the course curriculum. CONCLUSIONS: A standardized pediatric sedation provider course was developed for sedation practitioners and consisted of a series of lectures and simulation scenarios. Overall satisfaction with the course was positive.


Subject(s)
Clinical Competence , Conscious Sedation/standards , Education, Medical, Continuing/organization & administration , Pediatrics/education , Curriculum , Educational Measurement , Feedback , Female , Humans , Male , Program Development , Program Evaluation
10.
Science ; 382(6672): 771, 2023 Nov 17.
Article in English | MEDLINE | ID: mdl-37972187

ABSTRACT

Pioneering statistician and father of information geometry.

11.
Psychoradiology ; 3: kkad003, 2023.
Article in English | MEDLINE | ID: mdl-38666119

ABSTRACT

Background: It has been postulated that musicianship can lead to enhanced brain and cognitive reserve, but the neural mechanisms of this effect have been poorly understood. Lifelong professional musicianship in conjunction with novel brain imaging techniques offers a unique opportunity to examine brain network differences between musicians and matched controls. Objective: In this study we aim to investigate how resting-state functional networks (FNs) manifest in lifelong active musicians. We will evaluate the FNs of lifelong musicians and matched healthy controls using resting-state functional magnetic resonance imaging. Methods: We derive FNs using the data-driven independent component analysis approach and analyze the functional network connectivity (FNC) between the default mode (DMN), sensory-motor (SMN), visual (VSN), and auditory (AUN) networks. We examine whether the linear regressions between FNC and age are different between the musicians and the control group. Results: The age trajectory of average FNC across all six pairs of FNs shows significant differences between musicians and controls. Musicians show an increase in average FNC with age while controls show a decrease (P = 0.013). When we evaluated each pair of FN, we note that in musicians FNC values increased with age in DMN-AUN, DMN-VSN, and SMN-VSN and in controls FNC values decreased with age in DMN-AUN, DMN-SMN, AUN-SMN, and SMN-VSN. Conclusion: This result provides early evidence that lifelong musicianship may contribute to enhanced brain and cognitive reserve. Results of this study are preliminary and need to be replicated with a larger number of participants.

12.
Endocrinology ; 164(4)2023 02 11.
Article in English | MEDLINE | ID: mdl-36718579

ABSTRACT

Several mouse models have been developed to study polycystic ovarian syndrome (PCOS), a leading cause of infertility in women. Treatment of mice with DHT for 90 days causes ovarian and metabolic phenotypes similar to women with PCOS. We used this 90-day DHT treatment paradigm to investigate the variable incidence and heterogeneity in 2 inbred mouse strains, NOD/ShiLtJ and 129S1/SvlmJ. NOD mice naturally develop type 1 diabetes, and recent meta-analysis found increased androgen excess and PCOS in women with type 1 diabetes. The 129S1 mice are commonly used in genetic manipulations. Both NOD and 129S1 DHT-treated mice had early vaginal opening, increased anogenital distance, and altered estrus cycles compared with control animals. Additionally, both NOD and 129S1 mice had reduced numbers of corpora lutea after DHT exposure, whereas NOD mice had decreased numbers of preantral follicles and 129S1 mice had reduced numbers of small antral follicles. NOD mice had increased body weight, decreased white adipocyte size, and improved glucose sensitivity in response to DHT, whereas 129S1 mice had increased body weight and white adipocyte size. NOD mice had increased expression of Adiponectin, Cidea, Srebp1a, and Srebp1b and 129S1 mice had decreased Pparg in the white adipose tissues, whereas both NOD and 129S1 mice had increased expression of Glut4 and Prdm16, suggesting DHT may differentially affect glucose transport, thermogenesis, and lipid storage in white adipose tissue. DHT causes different ovarian and metabolic responses in NOD and 129S1 mice, suggesting that strain differences may allow further elucidation of genetic contributions to PCOS.


Subject(s)
Diabetes Mellitus, Type 1 , Polycystic Ovary Syndrome , Humans , Female , Mice , Animals , Polycystic Ovary Syndrome/metabolism , Diabetes Mellitus, Type 1/complications , Mice, Inbred NOD , Disease Models, Animal , Body Weight/physiology , Dihydrotestosterone
13.
Stat Med ; 31(19): 2123-36, 2012 Aug 30.
Article in English | MEDLINE | ID: mdl-22388709

ABSTRACT

Reliable surveillance models are an important tool in public health because they aid in mitigating disease outbreaks, identify where and when disease outbreaks occur, and predict future occurrences. Although many statistical models have been devised for surveillance purposes, none are able to simultaneously achieve the important practical goals of good sensitivity and specificity, proper use of covariate information, inclusion of spatio-temporal dynamics, and transparent support to decision-makers. In an effort to achieve these goals, this paper proposes a spatio-temporal conditional autoregressive hidden Markov model with an absorbing state. The model performs well in both a large simulation study and in an application to influenza/pneumonia fatality data.


Subject(s)
Disease Outbreaks/statistics & numerical data , Influenza, Human/epidemiology , Population Surveillance/methods , Space-Time Clustering , Bayes Theorem , Computer Simulation , Humans , Markov Chains , Poisson Distribution , Syndrome , United States/epidemiology
14.
Article in English | MEDLINE | ID: mdl-35162667

ABSTRACT

A conceptual model is presented of two MW-scale low enthalpy mine water geothermal heat pump schemes that are being developed in Tyneside, UK. The Abbotsford Road scheme (54.955° N 1.556° W) is operating (as of May 2021) at 20-30 L/s, abstracting groundwater (and heat) from an unmined Coal Measures Upper Aquifer System (UAS) and reinjecting to the deeper High Main Aquifer System (HMAS), associated with the High Main (E) coal workings and the overlying High Main Post sandstone. A similar scheme, 700 m away at Nest Road (54.959° N 1.564° W), abstracts at 40 L/s from the HMAS, recovers heat from the mine water and reinjects the thermally spent water to deeper workings associated with the Hutton (L), Harvey-Beaumont (N) (and possibly other) coal seams, termed the Deep Mined Aquifer System (DMAS). The three aquifer systems are vertically discontinuous and possess different hydraulic (storage, transmissivity and continuity) properties that would have been near-impossible to predict in advance of drilling. At the sites, 10 boreholes were drilled to obtain five usable production/reinjection boreholes. Development of mine water geothermal energy schemes thus carries a significant project risk, and also a potential ongoing maintenance burden related to iron hydroxide scaling. These do not preclude mine water geothermal as a useful low carbon heating and cooling technology, but the involvement of skilled hydrogeologists, hydrochemists, mining and groundwater engineers is a pre-requisite.


Subject(s)
Geothermal Energy , Groundwater , Mining , United Kingdom , Water
15.
Ophthalmol Sci ; 2(2)2022 Jun.
Article in English | MEDLINE | ID: mdl-35662803

ABSTRACT

Objective: To describe optical coherence tomography (SD-OCT) features, age, gender, and systemic variables that may be used in machine/deep learning studies to identify high-risk patient subpopulations with high risk of progression to geographic atrophy (GA) and visual acuity (VA) loss in the short term. Design: prospective, longitudinal study. Subjects: We analyzed imaging data from patients with iAMD (N= 316) enrolled in Age-Related Eye Disease Study 2 (AREDS2) Ancillary SD-OCT with adequate SD-OCT imaging for repeated measures. Methods: Qualitative and quantitative multimodal variables from the database were derived at each yearly visit over 5 years. Based on statistical analyses developed in the field of cardiology, an algorithm was developed and used to select person-years without GA on colour fundus photography or SD-OCT at baseline. The analysis employed machine learning approaches to generate classification trees. Eyes were stratified as low, average, above average and high risk in 1 or 2 years, based on OCT and demographic features by the risk of GA development or decreased VA by 5+ and 10+ letters. Main outcome measures: new onset of SD-OCT-determined GA and VA loss. Results: We identified multiple retinal and subretinal SD-OCT and demographic features from the baseline visit, each of which independently conveyed low to high risk of new-onset GA or VA loss on each of the follow-up visits at 1 or 2 years. Conclusion: We propose a risk-stratified classification of iAMD based on the combination of OCT-derived retinal features, age, gender and systemic variables for progression to OCT-determined GA and/or VA loss. After external validation, the composite early endpoints may be used as exclusion or inclusion criteria for future clinical studies of iAMD focused on prevention of GA progression or VA loss.

16.
Brain Sci ; 11(1)2021 Jan 06.
Article in English | MEDLINE | ID: mdl-33419228

ABSTRACT

There is a significant body of research that has identified specific, high-end cognitive demand activities and lifestyles that may play a role in building cognitive brain reserve, including volume changes in gray matter and white matter, increased structural connectivity, and enhanced categorical perception. While normal aging produces trends of decreasing white matter (WM) integrity, research on cognitive brain reserve suggests that complex sensory-motor activities across the life span may slow down or reverse these trends. Previous research has focused on structural and functional changes to the human brain caused by training and experience in both linguistic (especially bilingualism) and musical domains. The current research uses diffusion tensor imaging to examine the integrity of subcortical white matter fiber tracts in lifelong musicians. Our analysis, using Tortoise and ICBM-81, reveals higher fractional anisotropy, an indicator of greater WM integrity, in aging musicians in bilateral superior longitudinal fasciculi and bilateral uncinate fasciculi. Statistical methods used include Fisher's method and linear regression analysis. Another unique aspect of this study is the accompanying behavioral performance data for each participant. This is one of the first studies to look specifically at musicianship across the life span and its impact on bilateral WM integrity in aging.

17.
Cell Death Dis ; 12(11): 1005, 2021 10 27.
Article in English | MEDLINE | ID: mdl-34707089

ABSTRACT

BH3 mimetics are increasingly used as anti-cancer therapeutics either alone or in conjunction with other chemotherapies. However, mounting evidence has also demonstrated that BH3 mimetics modulate varied amounts of apoptotic signaling in healthy immune populations. In order to maximize their clinical potential, it will be essential to understand how BH3 mimetics affect discrete immune populations and to determine how BH3 mimetic pressure causes immune system adaptation. Here we focus on the BCL-2 specific inhibitor venetoclax (ABT-199) and its effects following short-term and long-term BCL-2 blockade on T cell subsets. Seven day "short-term" ex vivo and in vivo BCL-2 inhibition led to divergent cell death sensitivity patterns in CD8+ T cells, CD4+ T cells, and Tregs resulting in shifting of global T cell populations towards a more memory T cell state with increased expression of BCL-2, BCL-XL, and MCL-1. However, twenty-eight day "long-term" BCL-2 blockade following T cell-depleted bone marrow transplantation did not lead to changes in the global T cell landscape. Despite the lack of changes in T cell proportions, animals treated with venetoclax developed CD8+ and CD4+ T cells with high levels of BCL-2 and were more resistant to apoptotic stimuli following expansion post-transplant. Further, we demonstrate through RNA profiling that T cells adapt while under BCL-2 blockade post-transplant and develop a more activated genotype. Taken together, these data emphasize the importance of evaluating how BH3 mimetics affect the immune system in different treatment modalities and disease contexts and suggest that venetoclax should be further explored as an immunomodulatory compound.


Subject(s)
Antineoplastic Agents/therapeutic use , Bridged Bicyclo Compounds, Heterocyclic/therapeutic use , Cell Death/drug effects , Memory T Cells/drug effects , Sulfonamides/therapeutic use , Animals , Antineoplastic Agents/pharmacology , Apoptosis , Bridged Bicyclo Compounds, Heterocyclic/pharmacology , Cell Line, Tumor , Humans , Mice , Sulfonamides/pharmacology
18.
Appl Opt ; 48(11): 2058-66, 2009 Apr 10.
Article in English | MEDLINE | ID: mdl-19363543

ABSTRACT

The effects of the formation of an optical standing wave during femtosecond laser-induced forward transfer of transparent films is analyzed using a numerical interference model. The dependence of the intensity distribution on a number of easily controllable experimental parameters is investigated. Results of the model are compared to experimental studies of the transfer of gadolinium gallium oxide (GdGaO) with a polymer sacrificial layer. The model allows us to explain the observed variation in deposit morphology with the size of the air gap, and why forward transfer of the GdGaO was possible below the ablation thresholds of polymer and oxide.

19.
IEEE Trans Vis Comput Graph ; 15(6): 1595-602, 2009.
Article in English | MEDLINE | ID: mdl-19834238

ABSTRACT

One way to provide global illumination for the scientist who performs an interactive sweep through a 3D scalar dataset is to pre-compute global illumination, resample the radiance onto a 3D grid, then use it as a 3D texture. The basic approach of repeatedly extracting isosurfaces, illuminating them, and then building a 3D illumination grid suffers from the non-uniform sampling that arises from coupling the sampling of radiance with the sampling of isosurfaces. We demonstrate how the illumination step can be decoupled from the isosurface extraction step by illuminating the entire 3D scalar function as a 3-manifold in 4-dimensional space. By reformulating light transport in a higher dimension, one can sample a 3D volume without requiring the radiance samples to aggregate along individual isosurfaces in the pre-computed illumination grid.


Subject(s)
Computer Graphics , Image Processing, Computer-Assisted/methods , Lighting/methods , Brain/anatomy & histology , Humans
20.
Microbes Infect ; 10(6): 613-9, 2008 May.
Article in English | MEDLINE | ID: mdl-18467145

ABSTRACT

The role of macrophages in the pathogenesis of anthrax is unresolved. Macrophages are believed to support the initiation of infection by Bacillus anthracis spores, yet are also sporicidal. Furthermore, it is believed that the anthrax toxins suppress normal macrophage function. However, the significance of toxin effects on macrophages has not been addressed in an in vivo infection model. We used mutant derivatives of murine macrophage RAW264.7 cells that are toxin receptor-negative (R3D) to test the role of toxin-targeting of macrophages during a challenge with spores of the Ames strain of B. anthracis in both in vivo and in vitro models. We found that the R3D cells were able to control challenge with Ames when mice were inoculated with the cells prior to spore challenge. These findings were confirmed in vitro by high dose spore infection of macrophages. Interestingly, whereas the R3D cells provided a significantly greater survival advantage against spores than did the wild type RAW264.7 cells or R3D-complemented cells, the protection afforded the mutant and wild type cells was equivalent against a bacillus challenge. The findings appear to be the first specific test of the role of toxin targeting of macrophages during infection with B. anthracis spores.


Subject(s)
Anthrax/pathology , Antigens, Bacterial/toxicity , Bacillus anthracis/pathogenicity , Bacterial Toxins/toxicity , Macrophages/drug effects , Macrophages/microbiology , Receptors, Peptide/metabolism , Spores, Bacterial/drug effects , Animals , Anthrax/immunology , Anthrax/mortality , Antigens, Bacterial/immunology , Bacillus anthracis/physiology , Bacterial Toxins/immunology , Host-Parasite Interactions , Macrophages/physiology , Mice , Mice, Inbred BALB C , Receptors, Cell Surface/genetics , Receptors, Cell Surface/metabolism
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