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Search Results: 1 - 10 of 221532 matches for " Andrea L Radtke "
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TBK1 Protects Vacuolar Integrity during Intracellular Bacterial Infection
Andrea L Radtke,Laura M Delbridge,Siddharth Balachandran,Glen N Barber,Mary X. D O'Riordan
PLOS Pathogens , 2007, DOI: 10.1371/journal.ppat.0030029
Abstract: TANK-binding kinase-1 (TBK1) is an integral component of Type I interferon induction by microbial infection. The importance of TBK1 and Type I interferon in antiviral immunity is well established, but the function of TBK1 in bacterial infection is unclear. Upon infection of murine embryonic fibroblasts with Salmonella enterica serovar Typhimurium (Salmonella), more extensive bacterial proliferation was observed in tbk1?/? than tbk1+/+ cells. TBK1 kinase activity was required for restriction of bacterial infection, but interferon regulatory factor-3 or Type I interferon did not contribute to this TBK1-dependent function. In tbk1?/?cells, Salmonella, enteropathogenic Escherichia coli, and Streptococcus pyogenes escaped from vacuoles into the cytosol where increased replication occurred, which suggests that TBK1 regulates the integrity of pathogen-containing vacuoles. Knockdown of tbk1 in macrophages and epithelial cells also resulted in increased bacterial localization in the cytosol, indicating that the role of TBK1 in maintaining vacuolar integrity is relevant in different cell types. Taken together, these data demonstrate a requirement for TBK1 in control of bacterial infection distinct from its established role in antiviral immunity.
Analysis of Interactions of Salmonella Type Three Secretion Mutants with 3-D Intestinal Epithelial Cells
Andrea L. Radtke,James W. Wilson,Shameema Sarker,Cheryl A. Nickerson
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0015750
Abstract: The prevailing paradigm of Salmonella enteropathogenesis based on monolayers asserts that Salmonella pathogenicity island-1 Type Three Secretion System (SPI-1 T3SS) is required for bacterial invasion into intestinal epithelium. However, little is known about the role of SPI-1 in mediating gastrointestinal disease in humans. Recently, SPI-1 deficient nontyphoidal Salmonella strains were isolated from infected humans and animals, indicating that SPI-1 is not required to cause enteropathogenesis and demonstrating the need for more in vivo-like models. Here, we utilized a previously characterized 3-D organotypic model of human intestinal epithelium to elucidate the role of all characterized Salmonella enterica T3SSs. Similar to in vivo reports, the Salmonella SPI-1 T3SS was not required to invade 3-D intestinal cells. Additionally, Salmonella strains carrying single (SPI-1 or SPI-2), double (SPI-1/2) and complete T3SS knockout (SPI-1/SPI-2: flhDC) also invaded 3-D intestinal cells to wildtype levels. Invasion of wildtype and TTSS mutants was a Salmonella active process, whereas non-invasive bacterial strains, bacterial size beads, and heat-killed Salmonella did not invade 3-D cells. Wildtype and T3SS mutants did not preferentially target different cell types identified within the 3-D intestinal aggregates, including M-cells/M-like cells, enterocytes, or Paneth cells. Moreover, each T3SS was necessary for substantial intracellular bacterial replication within 3-D cells. Collectively, these results indicate that T3SSs are dispensable for Salmonella invasion into highly differentiated 3-D models of human intestinal epithelial cells, but are required for intracellular bacterial growth, paralleling in vivo infection observations and demonstrating the utility of these models in predicting in vivo-like pathogenic mechanisms.
The Energetic Performance of Vehicles
J.L. Radtke
The Open Fuels & Energy Science Journal , 2008, DOI: 10.2174/1876973X00801010011]
Abstract: Various methods of determining the energetic performance of vehicles were described and compared. Earlier work emphasized maximum vehicle power and theoretical performance limits, and characterized the vehicle or payload in terms of weight. Energetic efficiency was calculated here as the payload mass times distance moved divided by thermal energy used. This efficiency was multiplied by average speed to yield an energetic performance parameter that was expressed in seconds, using SI units. The differential form of this parameter was twice the useful payload kinetic energy divided by thermal power expenditure. A transportation matrix was developed, describing how vehicles are most commonly used in terms of speed, efficiency, GHG emissions, payload mass and energetic performance. Vehicles with the highest level of energetic performance have efficient powerplants, high payload to gross mass ratios, or reduced friction with the surrounding environment.
Induction and maintenance of protective CD8+ T cells against malaria liver stages: implications for vaccine development
Tse, Sze-Wah;Radtke, Andrea J;Zavala, Fidel;
Memórias do Instituto Oswaldo Cruz , 2011, DOI: 10.1590/S0074-02762011000900022
Abstract: cd8+ t cells against malaria liver stages represent a major protective immune mechanism against infection. following induction in the peripheral lymph nodes by dendritic cells (dcs), these cd8+ t cells migrate to the liver and eliminate parasite infected hepatocytes. the processing and presentation of sporozoite antigen requires tap mediated transport of major histocompatibility complex class i epitopes to the endoplasmic reticulum. importantly, in dcs this process is also dependent on endosome-mediated cross presentation while this mechanism is not required for epitope presentation on hepatocytes. protective cd8+ t cell responses are strongly dependent on the presence of cd4+ t cells and the capacity of sporozoite antigen to persist for a prolonged period of time. while human trials with subunit vaccines capable of inducing antibodies and cd4+ t cell responses have yielded encouraging results, an effective anti-malaria vaccine will likely require vaccine constructs designed to induce protective cd8+ t cells against malaria liver stages.
Low-variance Monte Carlo Solutions of the Boltzmann Transport Equation
Nicolas G. Hadjiconstantinou,Gregg A. Radtke,Lowell L. Baker
Physics , 2009,
Abstract: We present and discuss a variance-reduced stochastic particle method for simulating the relaxation-time model of the Boltzmann transport equation. The present paper focuses on the dilute gas case, although the method is expected to directly extend to all fields (carriers) for which the relaxation-time approximation is reasonable. The variance reduction, achieved by simulating only the deviation from equilibrium, results in a significant computational efficiency advantage compared to traditional stochastic particle methods in the limit of small deviation from equilibrium. More specifically, the proposed method can efficiently simulate arbitrarily small deviations from equilibrium at a computational cost that is independent of the deviation from equilibrium, which is in sharp contrast to traditional particle methods.
Regulation of Anti-Plasmodium Immunity by a LITAF-like Transcription Factor in the Malaria Vector Anopheles gambiae
Ryan C. Smith,Abraham G. Eappen,Andrea J. Radtke,Marcelo Jacobs-Lorena
PLOS Pathogens , 2012, DOI: 10.1371/journal.ppat.1002965
Abstract: The mosquito is the obligate vector for malaria transmission. To complete its development within the mosquito, the malaria parasite Plasmodium must overcome the protective action of the mosquito innate immune system. Here we report on the involvement of the Anopheles gambiae orthologue of a conserved component of the vertebrate immune system, LPS-induced TNFα transcription factor (LITAF), and its role in mosquito anti-Plasmodium immunity. An. gambiae LITAF-like 3 (LL3) expression is up-regulated in response to midgut invasion by both rodent and human malaria parasites. Silencing of LL3 expression greatly increases parasite survival, indicating that LL3 is part of an anti-Plasmodium defense mechanism. Electrophoretic mobility shift assays identified specific LL3 DNA-binding motifs within the promoter of SRPN6, a gene that also mediates mosquito defense against Plasmodium. Further experiments indicated that these motifs play a direct role in LL3 regulation of SRPN6 expression. We conclude that LL3 is a transcription factor capable of modulating SRPN6 expression as part of the mosquito anti-Plasmodium immune response.
Transcriptomic and functional analysis of the Anopheles gambiae salivary gland in relation to blood feeding
Suchismita Das, Andrea Radtke, Young-Jun Choi, Antonio M Mendes, Jesus G Valenzuela, George Dimopoulos
BMC Genomics , 2010, DOI: 10.1186/1471-2164-11-566
Abstract: We have performed a global transcriptome analysis of the A. gambiae salivary gland response to blood-feeding, to identify candidate genes that are involved in hematophagy. A total of 4,978 genes were found to be transcribed in this tissue. A comparison of salivary gland transcriptomes prior to and after blood-feeding identified 52 and 41 transcripts that were significantly up-regulated and down-regulated, respectively. Ten genes were further selected to assess their role in the blood-feeding process using RNAi-mediated gene silencing methodology. Depletion of the salivary gland genes encoding D7L2, anophelin, peroxidase, the SG2 precursor, and a 5'nucleotidase gene significantly increased probing time of A. gambiae mosquitoes and thereby their capacity to blood-feed.The salivary gland transcriptome comprises approximately 38% of the total mosquito transcriptome and a small proportion of it is dynamically changing already at two hours in response to blood feeding. A better understanding of the salivary gland transcriptome and its function can contribute to the development of pathogen transmission control strategies and the identification of medically relevant bioactive compounds.Adult mosquitoes feed on sugar to obtain energy for flight and other activities, while anautogenous females need a blood meal to develop eggs. Salivary glands and the saliva of insect disease vectors have attracted considerable attention because of their role in pathogen transmission and their production of pharmacologically active factors [1-4].It is during the blood-feeding process that the Plasmodium parasite is taken up from an infected A. gambiae host. Once inside the mosquito, Plasmodium undergoes several developmental transitions and eventually becomes a sporozoite, which invades the salivary glands. This invasion represents a critical step in the transmission of the parasite to the vertebrate host. Completion of the infection depends on the injection of sporozoites, through the saliva
A Simple Trap for the Capture New-Emergent Salmonid Fry in Streams
Grzegorz Radtke
Archives of Polish Fisheries , 2008, DOI: 10.2478/s10086-008-0007-3
Abstract: A simple trap was built for capturing salmonid fry emerging from natural spawning redds in streams. The trap is shaped like a cap with a vertical PVC tube. Since the trap is not attached permanently to the substrate, settled debris can be cleaned out regularly, and the trap can be deployed in streams with large amounts of drifting organic material. Its simple construction means that it is easy to use. Based on the comparison of the effectiveness of two types of traps on artificial redds, the catch efficiency of the newly constructed trap was determined to be 37%.
Ulrike Kl ppel: XX0XY ungel st. Hermaphroditismus, Sex und Gender in der deutschen Medizin. Eine historische Studie zur Intersexualit t. Bielefeld: transcript Verlag 2010.
Sarah Radtke
querelles-net , 2010,
Abstract: Ulrike Kl ppel führt in ihrer materialreichen Studie vor, dass Hermaphroditismus für die Medizin immer wieder Anlass war, sich mit der Vielfalt der das Geschlecht bestimmenden Faktoren – Gestalt und Form der Genitalien, Chromosomengeschlecht, Keimdrüsengeschlecht (Hoden vs. Eierst cke), Hormonhaushalt, Geschlechtsrolle und Geschlechtsidentit t – zu befassen und zu versuchen, Geschlechtszugeh rigkeiten verbindlich festzulegen. Neben einem historischen Teil, der vor allem die Medizingeschichte der Frühen Neuzeit, der Aufkl rungszeit und des 19. Jahrhunderts in den Blick nimmt, wird im zweiten Teil der Arbeit der Zusammenhang zwischen der Formierung des gender-Konzepts und dem damit verbundenen Paradigmenwechsel in der Behandlung von Intersexualit t dargestellt. Ulrike Kl ppel’s extensive study shows that hermaphroditism has, over and over again, caused medical science to study the variety of factors that set the gender – shape and form of the genitals, gender according to chromosomes, gender according to gonads (testicles vs. ovaries), hormonal balance, gender role and gender identity – and to try to determine a mandatory affiliation with a certain gender. In addition to a historical part which mainly sheds light on the medical history of the Early Modern Age, the Age of Enlightenment, and the 19th century, the second part of the study illustrates the correlation between the forming of the gender concept and the related paradigm change in the treatment of intersexuality.
CNPase Expression in Olfactory Ensheathing Cells
Christine Radtke,Masanori Sasaki,Karen L. Lankford,Vittorio Gallo,Jeffery D. Kocsis
Journal of Biomedicine and Biotechnology , 2011, DOI: 10.1155/2011/608496
Abstract: A large body of work supports the proposal that transplantation of olfactory ensheathing cells (OECs) into nerve or spinal cord injuries can promote axonal regeneration and remyelination. Yet, some investigators have questioned whether the transplanted OECs associate with axons and form peripheral myelin, or if they recruit endogenous Schwann cells that form myelin. Olfactory bulbs from transgenic mice expressing the enhanced green fluorescent protein (eGFP) under the control of the 2-3-cyclic nucleotide 3-phosphodiesterase (CNPase) promoter were studied. CNPase is expressed in myelin-forming cells throughout their lineage. We examined CNPase expression in both in situ in the olfactory bulb and in vitro to determine if OECs express CNPase commensurate with their myelination potential. eGFP was observed in the outer nerve layer of the olfactory bulb. Dissociated OECs maintained in culture had both intense eGFP expression and CNPase immunostaining. Transplantation of OECs into transected peripheral nerve longitudinally associated with the regenerated axons. These data indicate that OECs in the outer nerve layer of the olfactory bulb of CNPase transgenic mice express CNPase. Thus, while OECs do not normally form myelin on olfactory nerve axons, their expression of CNPase is commensurate with their potential to form myelin when transplanted into injured peripheral nerve.
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