bluuebunny/crossref_metadata_2025 huggingface dataset:
In Vitro Studies of the Activity of Dithiocarbamate Organoruthenium Complexes against Clinically Relevant Fungal Pathogens
Authors: Donnici Claudio , Nogueira Luciano , Araujo Maria , Oliveira Sheila , Magalhães Thais , Lopes Miriam , Silva Ana , Ferreira Ana , Martins Cleide , De Resende Stoianoff Maria
Published: April 2014

The in vitro antifungal activity of nine dirutheniumpentadithiocarbamate complexes C1–C9 was investigated and assessed for its activity against four different fungal species with clinical interest and related to invasive fungal infections (IFIs), such as Candida spp. [C. albicans (two clinical isolates), C. glabrata, C. krusei, C. parapsolisis, C. tropicalis, C.dubliniensis (six clinical isolates)], Paracoccidioides brasiliensis (seven clinical isolates), Cryptococcus neoformans and Sporothrix schenckii. All synthesized complexes C1–C9 and also the free ligands L1–L9 were submitted to in vitro tests against those fungi and the results are very promising, since some of the obtained MIC (minimal inhibitory concentration) values were very low (from 10−6 mol mL−1 to 10−8 mol mL−1) against all investigated clinically relevant fungal pathogens, except for C. glabrata, that the MIC values are close to the ones obtained for fluconazole, the standard antifungal agent tested. Preliminary structure-activity relations (SAR) might be suggested and a strong influence from steric and lipophilic parameters in the antifungal activity can be noticed. Cytotoxicity assays (IC50) showed that the complexes are not as toxic (IC50 values are much higher—30 to 200 fold—than MIC values). These ruthenium complexes are very promising lead compounds for novel antifungal drug development, especially in IFIs, one of most harmful emerging infection diseases (EIDs).
Epigenetic Effects of Human Breast Milk
Authors: Verduci Elvira , Banderali Giuseppe , Barberi Salvatore , Radaelli Giovanni , Lops Alessandra , Betti Federica , Riva Enrica , Giovannini Marcello
Published: April 2014

A current aim of nutrigenetics is to personalize nutritional practices according to genetic variations that influence the way of digestion and metabolism of nutrients introduced with the diet. Nutritional epigenetics concerns knowledge about the effects of nutrients on gene expression. Nutrition in early life or in critical periods of development, may have a role in modulating gene expression, and, therefore, have later effects on health. Human breast milk is well-known for its ability in preventing several acute and chronic diseases. Indeed, breastfed children may have lower risk of neonatal necrotizing enterocolitis, infectious diseases, and also of non-communicable diseases, such as obesity and related-disorders. Beneficial effects of human breast milk on health may be associated in part with its peculiar components, possible also via epigenetic processes. This paper discusses about presumed epigenetic effects of human breast milk and components. While evidence suggests that a direct relationship may exist of some components of human breast milk with epigenetic changes, the mechanisms involved are still unclear. Studies have to be conducted to clarify the actual role of human breast milk on genetic expression, in particular when linked to the risk of non-communicable diseases, to potentially benefit the infant’s health and his later life.
The Proteome of the Murine Presynaptic Active Zone
Authors: Laßek Melanie , Weingarten Jens , Volknandt Walter
Published: April 2014

The proteome of the presynaptic active zone controls neurotransmitter release and the short- and long-term structural and functional dynamics of the nerve terminal. The proteinaceous inventory of the presynaptic active zone has recently been reported. This review will evaluate the subcellular fractionation protocols and the proteomic approaches employed. A breakthrough for the identification of the proteome of the presynaptic active zone was the successful employment of antibodies directed against a cytosolic epitope of membrane integral synaptic vesicle proteins for the immunopurification of synaptic vesicles docked to the presynaptic plasma membrane. Combining immunopurification and subsequent analytical mass spectrometry, hundreds of proteins, including synaptic vesicle proteins, components of the presynaptic fusion and retrieval machinery, proteins involved in intracellular and extracellular signaling and a large variety of adhesion molecules, were identified. Numerous proteins regulating the rearrangement of the cytoskeleton are indicative of the functional and structural dynamics of the presynapse. This review will critically discuss both the experimental approaches and prominent protein candidates identified. Many proteins have not previously been assigned to the presynaptic release sites and may be directly involved in the short- and long-term structural modulation of the presynaptic compartment. The identification of proteinaceous constituents of the presynaptic active zone provides the basis for further analyzing the interaction of presynaptic proteins with their targets and opens novel insights into the functional role of these proteins in neuronal communication.
Chronology of Fabry-Perot Interferometer Fiber-Optic Sensors and Their Applications: A Review
Authors: Islam Md. , Ali Muhammad , Lai Man-Hong , Lim Kok-Sing , Ahmad Harith
Published: April 2014

Optical fibers have been involved in the area of sensing applications for more than four decades. Moreover, interferometric optical fiber sensors have attracted broad interest for their prospective applications in sensing temperature, refractive index, strain measurement, pressure, acoustic wave, vibration, magnetic field, and voltage. During this time, numerous types of interferometers have been developed such as Fabry-Perot, Michelson, Mach-Zehnder, Sagnac Fiber, and Common-path interferometers. Fabry-Perot interferometer (FPI) fiber-optic sensors have been extensively investigated for their exceedingly effective, simple fabrication as well as low cost aspects. In this study, a wide variety of FPI sensors are reviewed in terms of fabrication methods, principle of operation and their sensing applications. The chronology of the development of FPI sensors and their implementation in various applications are discussed.
Model Parameter Adaption-Based Multi-Model Algorithm for Extended Object Tracking Using a Random Matrix
Authors: Li Borui , Mu Chundi , Han Shuli , Bai Tianming
Published: April 2014

Traditional object tracking technology usually regards the target as a point source object. However, this approximation is no longer appropriate for tracking extended objects such as large targets and closely spaced group objects. Bayesian extended object tracking (EOT) using a random symmetrical positive definite (SPD) matrix is a very effective method to jointly estimate the kinematic state and physical extension of the target. The key issue in the application of this random matrix-based EOT approach is to model the physical extension and measurement noise accurately. Model parameter adaptive approaches for both extension dynamic and measurement noise are proposed in this study based on the properties of the SPD matrix to improve the performance of extension estimation. An interacting multi-model algorithm based on model parameter adaptive filter using random matrix is also presented. Simulation results demonstrate the effectiveness of the proposed adaptive approaches and multi-model algorithm. The estimation performance of physical extension is better than the other algorithms, especially when the target maneuvers. The kinematic state estimation error is lower than the others as well.
A Multi-Resolution Approach for an Automated Fusion of Different Low-Cost 3D Sensors
Authors: Dupuis Jan , Paulus Stefan , Behmann Jan , Plümer Lutz , Kuhlmann Heiner
Published: April 2014

The 3D acquisition of object structures has become a common technique in many fields of work, e.g., industrial quality management, cultural heritage or crime scene documentation. The requirements on the measuring devices are versatile, because spacious scenes have to be imaged with a high level of detail for selected objects. Thus, the used measuring systems are expensive and require an experienced operator. With the rise of low-cost 3D imaging systems, their integration into the digital documentation process is possible. However, common low-cost sensors have the limitation of a trade-off between range and accuracy, providing either a low resolution of single objects or a limited imaging field. Therefore, the use of multiple sensors is desirable. We show the combined use of two low-cost sensors, the Microsoft Kinect and the David laserscanning system, to achieve low-resolved scans of the whole scene and a high level of detail for selected objects, respectively. Afterwards, the high-resolved David objects are automatically assigned to their corresponding Kinect object by the use of surface feature histograms and SVM-classification. The corresponding objects are fitted using an ICP-implementation to produce a multi-resolution map. The applicability is shown for a fictional crime scene and the reconstruction of a ballistic trajectory.
Sorption of Emerging Organic Wastewater Contaminants to Four Soils
Authors: Roberts Sarah , Higgins Christopher , McCray John
Published: April 2014

Conventional onsite wastewater treatment system design relies on a septic tank and soil treatment unit (STU) for treatment of wastewater and integration of the final effluent into the environment. Organic water contaminants (OWCs), chemicals found in pharmaceutical drugs, detergents, surfactants, and other personal care and cleaning products, have been observed in septic tank effluent and the environment. Sorption of OWC mass to soil is a key mechanism in the removal and retardation of many of these chemicals in effluent as it travels through an STU. The primary purpose of this study was to investigate the relationship between the fraction of organic carbon of soil and the equilibrium sorption partitioning coefficient of a selected group of relevant and diverse OWCs. A secondary goal is to evaluate current methods of modeling the sorption of selected OWCs in soil. Five point Freundlich isotherms were constructed from equilibrium sorption batch tests for target OWCs with four different soils. For soils with organic carbon fraction between 0.021 and 0.054, Kd values were calculated between 60 and 185 for 4-nonylphenol, 75 to 260 for triclosan, 115 to 270 for bisphenol-A, 3 to 255 for 17β-estradiol, 40 to 55 for 17α-ethynylestradiol, and 28 to 70 for estrone. An empirically derived, direct relationship between foc and Kd may be a useful approach to estimating sorption for a soil based on organic carbon content.
Biométrie et types de ramification chez quelques graminées tropicales. Applications à la définition des formes biologiques (XVIe note sur les Graminées d'Afrique Tropicale)
Authors: Jacques-Félix H.
Published: April 2014

La biométrie culmaire, appliquée à quatre espèces de graminées tropicales, nous a permis de reconnaître quatre types morphologiques basés sur la position de la ramification :

1°) ramification tallée, chez l'Eleusine tristachya ;

2°) ramification étagée, chez le Pennisetum glaucum ;

3°) ramification paniculée chez le Schizachyrium plaly phyllum ;

4°) ramification fasciculée chez l'Eleusine indica.

Ces modes de ramification et les propres données de la biométrie culmaires, joints à quelques autres caractères écologiques et morphologiques, devraient permettre de définir quelques types biologiques fondamentaux.

Une nouvelle hypothèse est également émise pour expliquer la croissance intermittente de l'Eleusine indica.
In Situ Recruitment of Human Bone Marrow-Derived Mesenchymal Stem Cells Using Chemokines for Articular Cartilage Regeneration
Authors: Park Min Sung , Kim Yun Hee , Jung Youngmee , Kim Soo Hyun , Park Jong Chul , Yoon Dong Suk , Kim Sung-Hwan , Lee Jin Woo
Published: April 2014

Bone marrow-derived mesenchymal stem cells (BMSCs) are a good cell source for regeneration of cartilage as they can migrate directly to the site of cartilage injury and differentiate into articular chondrocytes. Articular cartilage defects do not heal completely due to the lack of chondrocytes or BMSCs at the site of injury. In this study, the chemotaxis of BMSCs toward chemokines, which may give rise to a complete regeneration of the articular cartilage, was investigated. CCR2, CCR4, CCR6, CXCR1, and CXCR2 were expressed in normal BMSCs and were increased significantly upon treatment with proinflammatory cytokines. BMSC migration was increased by MIP-3α and IL-8 more than by MCP-1 or SDF-1α. IL-8 and MIP-3α significantly enhanced the chemotaxis of BMSCs compared with MCP-1, SDF-1α, or PBS. Human BMSC recruitment to transplanted scaffolds containing either IL-8 or MIP-3α significantly increased in vivo compared to scaffolds containing PBS. Furthermore, IL-8- and MIP-3α-containing scaffolds enhanced tissue regeneration of an osteochondral defect site in beagle knee articular cartilage. Therefore, this study suggests that IL-8 and MIP-3α are the candidates that induce the regeneration of damaged articular cartilage.
Modulation of Alloimmune Responses by Interleukin-10 Prevents Rejection of Implanted Allogeneic Smooth Muscle Cells and Restores Postinfarction Ventricular Function
Authors: Dhingra Sanjiv , Wu Jun , Li Shu-Hong , Guo Jian , Huang Xi-Ping , Mihic Anton , Hu Jim , Weisel Richard D. , Li Ren-Ke
Published: April 2014

Interleukin-10 (IL-10) gene transduction into allogeneic smooth muscle cells (SMCs) was evaluated to improve the long-term benefits of allogeneic cell transplantation into infarcted myocardium. Allogeneic cells, including SMCs, have been demonstrated to restore cardiac function and repair the infarcted myocardium, but late rejection of the transplanted cells by the host immune system may reverse the benefits of cell therapy. In a rat myocardial infarction model, three groups of rats were injected with either unmodified autologous, unmodified allogeneic, or allogeneic + IL-10 SMCs into the infarct region. Three weeks later, most of the allogeneic cells were rejected, whereas autologous cells were engrafted in the myocardium. IL-10 gene transduction of the allogeneic SMCs significantly improved the cell survival. To understand the mechanism of this improved survival, we evaluated the host immune responses against the SMCs. Allogeneic SMCs expressing IL-10 decreased leukocyte-mediated cytotoxicity in coculture, decreased the number of cytotoxic CD8+T-cells, and increased the number of CD4+CD25+regulatory T-cells in vitro and in vivo. Furthermore, IL-10 prevented the production of antidonor antibodies by the recipients against the allogeneic SMCs. Transplantation of unmodified autologous SMCs, but not unmodified allogeneic SMCs, significantly improved fractional shortening and left ventricular dimensions compared to the media-injected control group. However, IL-10 gene-enhanced allogeneic SMCs improved ventricular function, increased wall thickness, and decreased scar length in association with their enhanced survival. We conclude that IL-10 gene-enhanced cell therapy with allogeneic SMCs prevents detrimental alloimmune responses in the recipient, thereby increasing the survival of transplanted allogeneic SMCs and more effectively restoring cardiac function.
Mesoporous cerium oxide nanospheres for the visible-light driven photocatalytic degradation of dyes
Authors: Muduli Subas K , Wang Songling , Chen Shi , Ng Chin Fan , Huan Cheng Hon Alfred , Sum Tze Chien , Soo Han Sen
Published: April 2014

A facile, solvothermal synthesis of mesoporous cerium oxide nanospheres is reported for the purpose of the photocatalytic degradation of organic dyes and future applications in sustainable energy research. The earth-abundant, relatively affordable, mixed valence cerium oxide sample, which consists of predominantly Ce7O12, has been characterized by powder X-ray diffraction, X-ray photoelectron and UV–vis spectroscopy, and transmission electron microscopy. Together with N2 sorption experiments, the data confirms that the new cerium oxide material is mesoporous and absorbs visible light. The photocatalytic degradation of rhodamin B is investigated with a series of radical scavengers, suggesting that the mechanism of photocatalytic activity under visible-light irradiation involves predominantly hydroxyl radicals as the active species.
Primary-tertiary diamine-catalyzed Michael addition of ketones to isatylidenemalononitrile derivatives
Authors: Kumar Akshay , Chimni Swapandeep Singh
Published: April 2014

Simple primary-tertiary diamines easily derived from natural primary amino acids were used to catalyze the Michael addition of ketones with isatylidenemalononitrile derivatives. Diamine 1a in combination with D-CSA as an additive provided Michael adducts in high yield (up to 94%) and excellent enantioselectivity (up to 99%). The catalyst 1a was successfully used to catalyze the three-component version of the reaction by a domino Knoevenagel–Michael sequence. The Michael adduct 4a was transformed into spirooxindole 6 by a reduction with sodium borohydride in a highly enantioselective manner.
COMPLEX ASSESSMENT MODEL FOR ADVANCED TECHNOLOGY DEPLOYMENT
Authors: Kildienė Simona , Zavadskas Edmundas Kazimieras , Tamošaitienė Jolanta
Published: April 2014

The construction sector constantly offers new products, more effective technologies and novel solutions aimed at improvement of the quality of human habitats and wider distribution of technologies. Currently, effective technologies that require less time and costs for production, installation and use are gaining greater significance. Among them are construction materials and technologies with increasingly popular sustainability features. Considering the above, the article offers a complex algorithm for assessing the deployment and distribution potential of a new technology/product. For this purpose, a multi-stage model of alternatives and criteria was suggested and an analytical multi-stage evaluation model has been designed. The practical example illustrates the assessment of micro environment using a combination of AHP (Analytic Hierarchy Process) and Permutation methods. The designed multi-criteria assessment model promotes accessibility of users to a technology, new product, a part of the product and a technological process.
Why is the lawn buzzing?
Authors: Jones Timothy
Published: April 2014

Graminoids, including grasses, are frequently described in the botanical literature as being wind-pollinated. This paper offers visual evidence for insect pollination of a grass. Three of the bees involved were found to have 100% grass pollen in their pollen sacs. In reviewing the literature for this paper, it was evident that those working with bees are well aware that these insects often pollinate graminoids. It is not clear why this information has not been incorporated into the botanical literature.
Cambios en las estructuras de los hogares Rurales. Formas de adaptación y resiliencia
Authors: Camarero Rioja Luis , Del Pino Artacho Julio A.
Published: April 2014

Este artículo trata sobre la capacidad de las estructuras de hogar para responder a las condiciones ambientales. En primer lugar, se expone la relación entre sostenibilidad demográfica y resiliencia de los hogares en las áreas rurales. A continuación, se presentan los mecanismos básicos de la adaptación entre las estructuras de hogar y entorno socioeconómico a través de las teorías de Chayánov y Le Play. Se analiza empíricamente la España rural, donde se constata una etapa de modernización de las estructuras de hogar, seguida más recientemente de cierta diversificación. Dentro de este proceso, destaca el número de hijos que alargan el periodo de convivencia con sus padres, constituyendo estrategias similares a las tradicionalmente empleadas por las familias troncales. En el actual contexto de las áreas rurales, las estructuras de hogar muestran su condición resiliente ante los cambios socioeconómicos.
Integrating Offshore Wind Power and Multiple Oil and Gas Platforms to the Onshore Power Grid Using VSC-HVDC Technology
Authors: Kolstad Magne Lorentzen , Årdal Atle Rygg , Sharifabadi Kamran , Undeland Tore Marvin
Published: April 2014

AbstractThis paper investigates the possibilities of integrating oil and gas platforms and offshore wind power to the onshore power grid. The main motivation for this proposal is to reduce the large greenhouse gas emissions associated with onsite power generation on traditional
oil and gas platforms and to improve the economy of offshore wind projects. The feasibility of a hypothetical power system in the North Sea consisting of five oil and gas platforms and one offshore wind power plant with a common connection to the onshore power grid is studied. This combined
grid integration concept has not been given much attention in similar previous publications. The connection to the onshore grid is realized through a high-voltage direct current transmission system based on voltage source converter technology. A dynamic simulation model of the system and a
control system are presented, and simulations are performed, using SimPowerSystems in MATLAB/Simulink, on system disturbances that are thought to be critical for the operation of the system. The simulation cases represent large disturbances that the system should be designed to withstand.
It was concluded that the system handles variations in the load very well and that the system configuration studied in this paper is regarded as a feasible way of integrating oil and gas platforms and offshore wind power to the onshore grid.
Modeling Low-Frequency Anthropogenic Noise in the Oceans: A Comparison of Propagation Models
Authors: Hovem Jens M. , Korakas Alexios
Published: April 2014

AbstractIncreased human activities in the marine environment in recent years have caused a significant general increase in ocean noise level, raising concerns over its impact on marine life. Anthropogenic noise in the oceans covers a wide range of frequencies down to 10 Hz
and can propagate over distances up to several tens of kilometers. Many environmental factors affect the propagation conditions and make it impossible to express the propagation with a simple equation. Mathematical/numerical modeling is required to predict and evaluate the impact of man-made
noise on marine life. The study compares transmission loss versus range calculated by a wavenumber integration model, a model based on the parabolic equation (PE), and a ray-tracing model. The models are tested and compared for a number of different scenarios with fluid and elastic bottom
layers in range-dependent environments. Each case is analyzed and interpreted at several frequencies from 15 to 250 Hz. The simulation results showed excellent agreement between the PE and the ray result for the transmission loss over a range of 10 km in a relative steep upslope elastic bottom
environment and for frequencies down to about 25 Hz. In another test, comparisons over a 50-km upslope continental shelf scenario resulted in good agreement for the fluid bottom for frequencies above 100 Hz and poorer for 50 Hz. Over the elastic high loss boom, the two results showed the same
general trend but with differences in details. Overall, the ray-tracing model appears to be an acceptable and efficient choice providing reliable predictions, even at low frequencies, in shallow water.
A new name for the western spruce budworm (Lepidoptera: Tortricidae)?
Authors: Gilligan Todd M. , Brown John W.
Published: April 2014

There currently is considerable confusion regarding the correct application of the nameChoristoneura occidentalisFreeman (Lepidoptera: Tortricidae). This name has historically been applied to the western spruce budworm, a serious forest pest in western North America. However, in 2008 Razowski transferred the African speciesArchips occidentalis(Walsingham) toChoristoneuraLederer and proposedC. freemaniRazowski as a replacement name for the western spruce budworm. The validity of these nomenclatural changes and alternative solutions to resolve the confusion they have caused are discussed. Illustrations of wing patterns and genitalia for the two species are provided.
MIF Promotes B Cell Chemotaxis through the Receptors CXCR4 and CD74 and ZAP-70 Signaling
Authors: Klasen Christina , Ohl Kim , Sternkopf Marieke , Shachar Idit , Schmitz Corinna , Heussen Nicole , Hobeika Elias , Levit-Zerdoun Ella , Tenbrock Klaus , Reth Michael , Bernhagen Jürgen , El Bounkari Omar
Published: April 2014

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine with chemokine-like functions that plays a pivotal role in the pathogenesis of inflammatory diseases by promoting leukocyte recruitment. We showed that MIF promotes the atherogenic recruitment of monocytes and T cells through its receptors CXCR2 and CXCR4. Effects of MIF on B cell recruitment have not been addressed. In this study, we tested the involvement of MIF in B cell chemotaxis and studied the underlying mechanism. We show that MIF promotes primary murine B cell chemotaxis in a dose-dependent manner, comparable to the B cell chemokines CXCL13 and CXCL12. Splenic B cells express CXCR4 and the receptor CD74 but not CXCR2. Inhibition of CXCR4 or CD74 or a genetic deficiency of Cd74 in primary B cells fully abrogated MIF-mediated B cell migration, implying cooperative involvement of both receptors. MIF stimulation of B cells resulted in a rapid increase in intracellular Ca2+ mobilization and F-actin polymerization. Intriguingly, the tyrosine kinase ZAP-70 was activated upon MIF and CXCL12 treatment in a CXCR4- and CD74-dependent manner. Pharmacological inhibition of ZAP-70 resulted in abrogation of primary B cell migration. Functional involvement of ZAP-70 was confirmed by small interfering RNA–mediated knockdown in Ramos B cell migration. Finally, primary B cells from ZAP-70 gene–deficient mice exhibited ablated transmigration in response to MIF or CXCL12. We conclude that MIF promotes the migration of B cells through a ZAP-70–dependent pathway mediated by cooperative engagement of CXCR4 and CD74. The data also suggest that MIF may contribute to B cell recruitment in vivo (e.g., in B cell–related immune disorders).
Mainstream Cigarette Smoke Exposure Attenuates Airway Immune Inflammatory Responses to Surrogate and Common Environmental Allergens in Mice, Despite Evidence of Increased Systemic Sensitization
Authors: Robbins Clinton S. , Pouladi Mahmoud A. , Fattouh Ramzi , Dawe David E. , Vujicic Neda , Richards Carl D. , Jordana Manel , Inman Mark D. , Stampfli Martin R.
Published: April 2014

The purpose of this study was to investigate the impact of mainstream cigarette smoke exposure (MTS) on allergic sensitization and the development of allergic inflammatory processes. Using two different experimental murine models of allergic airways inflammation, we present evidence that MTS increased cytokine production by splenocytes in response to OVA and ragweed challenge. Paradoxically, MTS exposure resulted in an overall attenuation of the immune inflammatory response, including a dramatic reduction in the number of eosinophils and activated (CD69+) and Th2-associated (T1ST2+) CD4 T lymphocytes in the lung. Although MTS did not impact circulating levels of OVA-specific IgE and IgG1, we observed a striking reduction in OVA-specific IgG2a production and significantly diminished airway hyperresponsiveness. MTS, therefore, plays a disparate role in the development of allergic responses, inducing a heightened state of allergen-specific sensitization, but dampening local immune inflammatory processes in the lung.
Shared and Unique Functions of the DExD/H-Box Helicases RIG-I, MDA5, and LGP2 in Antiviral Innate Immunity
Authors: Yoneyama Mitsutoshi , Kikuchi Mika , Matsumoto Kanae , Imaizumi Tadaatsu , Miyagishi Makoto , Taira Kazunari , Foy Eileen , Loo Yueh-Ming , Gale Michael , Akira Shizuo , Yonehara Shin , Kato Atsushi , Fujita Takashi
Published: April 2014

The cellular protein retinoic acid-inducible gene I (RIG-I) senses intracellular viral infection and triggers a signal for innate antiviral responses including the production of type I IFN. RIG-I contains a domain that belongs to a DExD/H-box helicase family and exhibits an N-terminal caspase recruitment domain (CARD) homology. There are three genes encoding RIG-I-related proteins in human and mouse genomes. Melanoma differentiation associated gene 5 (MDA5), which consists of CARD and a helicase domain, functions as a positive regulator, similarly to RIG-I. Both proteins sense viral RNA with a helicase domain and transmit a signal downstream by CARD; thus, these proteins share overlapping functions. Another protein, LGP2, lacks the CARD homology and functions as a negative regulator by interfering with the recognition of viral RNA by RIG-I and MDA5. The nonstructural protein 3/4A protein of hepatitis C virus blocks the signaling by RIG-I and MDA5; however, the V protein of the Sendai virus selectively abrogates the MDA5 function. These results highlight ingenious mechanisms for initiating antiviral innate immune responses and the action of virus-encoded inhibitors.
CD21/CD19 Coreceptor Signaling Promotes B Cell Survival during Primary Immune Responses
Authors: Barrington Robert A. , Zhang Ming , Zhong Xuemei , Jonsson Helena , Holodick Nichol , Cherukuri Anu , Pierce Susan K. , Rothstein Thomas L. , Carroll Michael C.
Published: April 2014

The adaptive immune response is tightly regulated to limit responding cells in an Ag-specific manner. On B cells, coreceptors CD21/CD19 modulate the strength of BCR signals, potentially influencing cell fate. The importance of the CD95 pathway was examined in response of B cells to moderate affinity Ag using an adoptive transfer model of lysozyme-specific Ig transgenic (HEL immunoglobulin transgene (MD4) strain) B cells. Although adoptively transferred Cr2+/+ MD4 B cells are activated and persist within splenic follicles of duck egg lysozyme-immunized mice, Cr2−/− MD4 B cells do not. In contrast, Cr2−/− MD4 lpr B cells persist after transfer, suggesting that lack of CD21/CD35 signaling results in CD95-mediated elimination. Cr2 deficiency did not affect CD95 levels, but cellular FLIP (c-FLIP) protein and mRNA levels were reduced 2-fold compared with levels in Cr2+/+ MD4 B cells. In vitro culture with Cr2+/+ MD4 B cells demonstrated that equimolar amounts of rHEL-C3d3 were more effective than hen egg lysozyme alone in up-regulating c-FLIP levels and for protection against CD95-mediated apoptosis. Collectively, this study implies a mechanism for regulating B cell survival in vivo whereby the strength of BCR signaling (including coreceptor) determines c-FLIP levels and protection from CD95-induced death.
The Role of Phase II Antioxidant Enzymes in Protecting Memory T Cells from Spontaneous Apoptosis in Young and Old Mice
Authors: Kim Hyon-Jeen , Nel Andre E.
Published: April 2014

Aging is associated with a functional decline and change in the phenotypic distribution of T cell subsets. The free radical theory of aging is widely promoted as the mechanistic basis for cellular senescence, including the immune system. Although the exact molecular explanation for the role of oxidative stress in cellular senescence is unclear, there is a connection to altered mitochondrial function, both as a contributor and as a target of oxidative stress. In this study we demonstrate that splenic T lymphocytes from old C57BL/6 mice exhibit a significant decline in mitochondrial membrane potential (Δψm). However, despite this change, there is a lower rate of withdrawal apoptosis in the memory CD4+ and CD8+ T cells. To explain the survival of these long-lived cells against a background of increased oxidative stress, we demonstrate increased glutathione production and phase II enzyme expression, which combine to protect memory T cells against oxidative stress, mitochondrial dysfunction, and cell death. The accumulation of memory T cells with aging explains higher phase II enzyme expression in CD4+ and CD8+ T cells from old mice. Compared with wild-type mice, mice lacking the expression of NF-E2-related factor-2, the transcription factor that regulates phase II enzyme expression, had a significantly enhanced rate of apoptosis in the presence of an oxidative stress stimulus. NF-E2-related factor-2-deficient T cells exhibit a bigger decline in Δψm and increased reactive oxygen species production than cells from wild-type animals. Taken together, we suggest that phase II enzyme expression and the accompanying increase in intracellular thiol levels protect memory T cells from mitochondrial dysfunction and spontaneous apoptosis.
EBV Infection of Human B Lymphocytes Leads to Down-Regulation of Bim Expression: Relationship to Resistance to Apoptosis
Authors: Clybouw Cyril , Mchichi Bouchra , Mouhamad Shahul , Auffredou Marie Thérèse , Bourgeade Marie Françoise , Sharma Surendra , Leca Gerald , Vazquez Aimé
Published: April 2014

EBV infects a large proportion of the human population worldwide and is one of the major viruses with human B lymphocyte tropism. It can immortalize human B lymphocytes and controls their resistance to apoptosis. EBV infection is associated with several lymphomas, including Burkitt’s lymphoma. In this report we show that EBV infection leads to the post-transcriptional down-regulation of expression of the proapoptotic protein Bim. This process involves the phosphorylation of BimEL by the constitutive EBV-activated kinase ERK1/2, followed by its degradation through the proteasome pathway. We also show that ectopic expression of BimEL in EBV-positive Burkitt’s lymphoma cells can enhance the sensitivity of these cells to serum deprivation-dependent apoptosis. Thus, EBV-mediated resistance to growth factor deprivation in human B lymphocytes is dependent on BimEL expression. Our data suggest that this regulatory pathway is an important contributor to the oncogenic potential of EBV.
Effects of Castration on Thymocyte Development in Two Different Models of Thymic Involution
Authors: Heng Tracy S. P. , Goldberg Gabrielle L. , Gray Daniel H. D. , Sutherland Jayne S. , Chidgey Ann P. , Boyd Richard L.
Published: April 2014

Age-associated thymic involution is accompanied by decreased thymic output. This adversely affects general immune competence and T cell recovery following cytoreductive treatments such as chemotherapy. A causal link between increasing sex steroids and age-related thymic atrophy is well established. Although castration has been demonstrated to regenerate the atrophied thymus, little is known about how this is initiated or the kinetics of thymocyte regeneration. The present study shows that although castration impacts globally across thymocyte development in middle-aged mice, the regenerative effects are initiated in the immature triple-negative compartment and early T lineage progenitors (ETP). Specifically, there was a reduction in number of ETP with age, which was restored following castration. There was, however, no change in ETP reconstitution potential in ETP at this age or following castration. Furthermore, in a chemotherapy-induced model of thymic involution, we demonstrate castration enhances intrathymic proliferation and promotes differentiation through the triple-negative program. Clinically, reversible sex steroid ablation is achieved hormonally, and thus presents a means of ameliorating immune inadequacies, for example, following chemotherapy for bone marrow transplantation. By improving our understanding of the kinetics of thymic recovery, this study will allow more appropriate timing of therapy to achieve maximal reconstitution, especially in the elderly.
IFN-γ Induces Apoptosis in Developing Mast Cells
Authors: Mann-Chandler Meredith N. , Kashyap Mohit , Wright Harry V. , Norozian Farnaz , Barnstein Brian O. , Gingras Sébastien , Parganas Evan , Ryan John J.
Published: April 2014

Mast cells are critical effectors of allergic disease, and are now implicated in immune responses observed in arthritis, multiple sclerosis, and heart disease. Because of their role in inflammation, understanding how mast cells develop is of clinical importance. In this study we determined the effects of IFN-γ on mast cell survival. Using in vitro culture of bone marrow cells in IL-3 plus stem cell factor, we found that the addition of IFN-γ induced apoptosis, as exhibited by the presence of subdiploid DNA and caspase activation. IFN-γ-mediated apoptosis was Stat1-dependent, and was accompanied by loss of mitochondrial membrane potential. Apoptosis was reduced in cultures of bone marrow cells derived from p53- or Bax-deficient mice, as well as H2K-Bcl-2 transgenic mice. IFN-γ hyperresponsiveness has been shown to result in inflammatory disease and death in mice lacking the regulatory protein suppressor of cytokine signaling (SOCS)-1. Bone marrow cells from SOCS-1 knockout (KO) mice failed to give rise to viable mast cells after culture in IL-3 plus stem cell factor, with profound apoptosis occurring as the cultures matured. However, bone marrow cells lacking both SOCS-1 and IFN-γ survived normally. This in vitro defect in mast cell development was recapitulated in vivo. SOCS-1 KO mice demonstrated a 67% decrease in peritoneal mast cell numbers relative to wild-type mice, a deficiency that was reversed in SOCS-1/IFN-γ KO mice. These data demonstrate the potent regulatory effects of IFN-γ on mast cell survival and show that this cytokine can elicit mast cell death in vitro and in vivo.
Acute IL-3 Priming Up-Regulates the Stimulus-Induced Raf-1-Mek-Erk Cascade Independently of IL-3-Induced Activation of Erk
Authors: Vilariño Natalia , Miura Katsushi , MacGlashan Donald W.
Published: April 2014

IL-3 is a potent priming cytokine for human basophils, inducing an increase of mediator release after stimulation. The mechanism of IL-3 priming of the basophil response to FcεRI aggregating stimuli remains unknown. We explored the regulation of several elements of IgE-mediated signaling by a short priming with IL-3. Early signaling events such as phosphorylation of Syk, Shc, linker for activation of T cells, and the calcium signal were not statistically affected by acute IL-3 priming. Downstream in the signaling cascade, a point of up-regulation was found at the level of Raf-1-Mek-Erk. Although the phosphorylation of Raf-1 was not changed by IL-3 priming, IL-3-primed anti-IgE-stimulated basophils showed a strong synergism for Mek and Erk phosphorylation when compared with either IL-3 or anti-IgE alone; pre-exposure to IL-3 induced a final 13-fold average increase over anti-IgE-induced Erk phosphorylation (6-fold above the sum of anti-IgE and IL-3 alone). The kinetics, dose response, and pharmacologic characteristics of the IL-3 priming of stimulus-induced Erk phosphorylation support the involvement of a yet unknown mechanism that is independent of IL-3-induced Erk and PI3K activation. This type of preactivation can be mimicked by incubation with the Ser-Thr kinase inhibitors, Ro-81–3220, or bisindoylmaleimide II.
Expansion of Functional Endogenous Antigen-Specific CD4+CD25+ Regulatory T Cells from Nonobese Diabetic Mice
Authors: Masteller Emma L. , Warner Matthew R. , Tang Qizhi , Tarbell Kristin V. , McDevitt Hugh , Bluestone Jeffrey A.
Published: April 2014

CD4+CD25+Foxp3+ regulatory T cells (Treg) are critical for controlling autoimmunity. Evidence suggests that Treg development, peripheral maintenance, and suppressive function are dependent on Ag specificity. However, there is little direct evidence that the Treg responsible for controlling autoimmunity in NOD mice or other natural settings are Ag specific. In fact, some investigators have argued that polyclonal Ag-nonspecific Treg are efficient regulators of immunity. Thus, the goal of this study was to identify, expand, and characterize islet Ag-specific Treg in NOD mice. Ag-specific Treg from NOD mice were efficiently expanded in vitro using IL-2 and beads coated with recombinant islet peptide mimic-MHC class II and anti-CD28 mAb. The expanded Ag-specific Treg expressed prototypic surface markers and cytokines. Although activated in an Ag-specific fashion, the expanded Treg were capable of bystander suppression both in vitro and in vivo. Importantly, the islet peptide mimic-specific Treg were more efficient than polyclonal Treg in suppressing autoimmune diabetes. These results provide a direct demonstration of the presence of autoantigen-specific Treg in the natural setting that can be applied as therapeutics for organ-specific autoimmunity.
The TCRβ Enhancer Is Dispensable for the Expression of Rearranged TCRβ Genes in Thymic DN2/DN3 Populations but Not at Later Stages
Authors: Busse Christian E. , Krotkova Anna , Eichmann Klaus
Published: April 2014

The Eβ enhancer has been shown to be dispensable for germline transcription of nonrearranged TCRβ segments but appears to be required for TCRβ V to DJ rearrangement. Eβ dependency of the subsequent expression of VDJ-rearranged TCRβ genes in thymic subpopulations has so far not been analyzed. We generated transgenic mice, using a Vβ8.2Dβ1Jβ1.3-rearranged TCRβ bacterial artificial chromosome, which lacked Eβ, and monitored transgene expression by flow cytometry using Vβ-specific mAbs and an IRES-eGFP reporter. Transgene expression was found in double negative (DN)2 and DN3 but not at later stages of thymopoesis. There was no toxicity associated with the transgene given that apoptosis in DN3, DN4 was not increased, and the number of DN4 cells generated from DN3 cells in reaggregate thymic organ cultures was not diminished. The transgenic TCRβ gave rise to a pre-TCR, as suggested by its ability to suppress endogenous TCRβ rearrangement, to facilitate β-selection on a TCRβ-deficient background and to inhibit γδ T cell lineage development. The results suggest that the Vβ8.2 promoter is sufficient to drive expression of rearranged TCRβ VDJ genes Eβ independently in DN2/DN3 but not at later stages.
In Vivo Humoral Immune Responses to Isolated Pneumococcal Polysaccharides Are Dependent on the Presence of Associated TLR Ligands
Authors: Sen Goutam , Khan Abdul Q. , Chen Quanyi , Snapper Clifford M.
Published: April 2014

We determined whether T cell-independent Ig isotype responses to isolated pneumococcal polysaccharides (PPS) required TLR signaling in vivo. IgG anti-PPS responses to PPS3, PPS14, and C-polysaccharide (C-PS) were virtually undetectable in TLR2−/− mice, whereas specific IgM induction was variably reduced compared with wild-type mice. All PPS-containing preparations induced IL-6 and TNF-α from wild-type, but not TLR2−/−, macrophages. TLR2 activity was distinct from that of PPS, in that it was phenol extractable. Immunization of wild-type mice with phenol-extracted PPS14 also resulted in a marked reduction in the IgG, although not the IgM-anti-PPS14, response compared with untreated PPS14. The commercial 23-valent PPS vaccine, Pneumovax-23 also contained TLR ligands (TLR2 and TLR4), which were absolutely critical for the IgG-inducing activity of the vaccine in mice. Finally, the commercial pneumococcal conjugate vaccine, Prevnar, contained a TLR2 ligand(s) that substantially enhanced both the primary and secondary anti-PPS responses in mice, especially the type 1 IgG isotypes. These data strongly suggest the absolute need for a distinct, TLR-dependent second signal for inducing in vivo IgG T cell-independent humoral immune responses to isolated pneumococcal polysaccharide Ags and highlight the potential importance of previously unappreciated copurified and/or contaminating TLR ligands in PPS vaccine preparations.
NKT Cell Stimulation with Glycolipid Antigen In Vivo: Costimulation-Dependent Expansion, Bim-Dependent Contraction, and Hyporesponsiveness to Further Antigenic Challenge
Authors: Uldrich Adam P. , Crowe Nadine Y. , Kyparissoudis Konstantinos , Pellicci Daniel G. , Zhan Yifan , Lew Andrew M. , Bouillet Philippe , Strasser Andreas , Smyth Mark J. , Godfrey Dale I.
Published: April 2014

Activation of NKT cells using the glycolipid α-galactosylceramide (α-GalCer) has availed many investigations into their immunoregulatory and therapeutic potential. However, it remains unclear how they respond to stimulation in vivo, which costimulatory pathways are important, and what factors (e.g., Ag availability and activation-induced cell death) limit their response. We have explored these questions in the context of an in vivo model of NKT cell dynamics spanning activation, population expansion, and subsequent contraction. Neither the B7/CD28 nor the CD40/CD40L costimulatory pathway was necessary for cytokine production by activated NKT cells, either early (2 h) or late (3 days) after initial stimulation, but both pathways were necessary for normal proliferative expansion of NKT cells in vivo. The proapoptotic Bcl-2 family member Bim was necessary for normal contraction of the NKT cell population between days 3–9 after stimulation, suggesting that the pool size is regulated by apoptotic death, similar to that of conventional T cells. Ag availability was not the limiting factor for NKT cell expansion in vivo, and a second α-GalCer injection induced a very blunted response, whereby cytokine production was reduced and further expansion did not occur. This appeared to be a form of anergy that was intrinsic to NKT cells and was not associated with inhibitory NK receptor signaling. Furthermore, NKT cells from mice prechallenged with α-GalCer in vivo showed little cytokine production and reduced proliferation in vitro. In summary, this study significantly enhances our understanding of how NKT cells respond to primary and secondary antigenic challenge in vivo.
Characterization of the Murine C3a Receptor Enhancer-Promoter: Expression Control by an Activator Protein 1 Sequence and an Ets-Like Site
Authors: Martin Carol B. , Martin Brian K.
Published: April 2014

The complement anaphylatoxins, C3a and C5a, exert their effects by binding to their respective receptors. A number of studies have implicated these proteins in human disease, yet little is known about anaphylatoxin receptor gene regulation. In this report, we demonstrate that most of the regulatory functions in the murine C3aR gene lie within 50 bp of the transcription start site. This region is critical for macrophage expression but does not have activity in a nonexpressing melanoma cell line. Within this small region are putative consensus binding sites for AP-1, NF-κB, Ets, and GATA transcription factors. Lack of a corresponding NF-κB site in the human sequence and lack of DNA binding activity in macrophage nuclear extracts suggests that the NF-κB site is nonfunctional. Luciferase data demonstrate that the GATA site functions as a negative regulatory element in RAW 264.7 macrophages. The AP-1 and Ets sites are critical for C3aR reporter gene expression, such that when each is mutated, a significant loss of activity is observed. Furthermore, we demonstrate that these sequences cooperate to mediate both basal and LPS-induced expression of C3aR. Interestingly, EMSA analyses demonstrate that the AP-1 site binds to c-Jun, and in vivo footprinting shows a typical footprint in this site, but the Ets site does not have a “typical” Ets footprint and does not bind to Ets-1/2 proteins in RAW 264.7 extracts. These data suggest that, although the control region for C3aR is small, interaction of several transcription factors can lead to complex patterns of gene regulation.