bluuebunny/crossref_metadata_2025 huggingface dataset:
Sistema de previsão de ocorrência de requeima em clones de batata suscetíveis e resistentes
Authors: Bosco Leosane Cristina , Heldwein Arno Bernardo , Lucas Dionéia Daiane Pitol , Trentin Gustavo , Grimm Edenir , Loose Luis Henrique
Published: April 2009

Sistemas de previsão e cultivares resistentes à requeima são importantes ferramentas para reduzir a quantidade de fungicidas utilizados e os custos de produção da batata. O objetivo deste trabalho foi avaliar a utilização do sistema de previsão Blitecast e de clones suscetíveis e resistentes no manejo da requeima da cultura da batata na região produtora de Santa Maria, Rio Grande do Sul (RS). Os experimentos foram conduzidos na Universidade Federal de Santa Maria, na primavera de 2006 e no outono de 2007, sendo os dados meteorológicos medidos continuamente acima do dossel das plantas. Foram utilizados 10 tratamentos arranjados no delineamento inteiramente casualizado, com quatro repetições. Os tratamentos foram diferenciados pelos valores de severidade acumulados, calculados pelo sistema Blitecast, e pelos clones SMIJ461-1 e SMINIA793101-3, caracterizados como resistentes à requeima, e Macaca (suscetível). Verificou-se que o sistema Blitecast não foi eficiente para prever o momento de aplicação de fungicida no controle da requeima. Portanto, este deve sofrer ajustes para ser utilizado em clones suscetíveis. Nos clones considerados resistentes, a aplicação de fungicidas com base na utilização do sistema Blitecast não tem efeito sobre a severidade da requeima e a produtividade da cultura da batata.
Pesquisa de interferon gama em tecido periodontal de ratos submetidos à movimentação dentária induzida
Authors: Silveira Daniel Mascarenhas da , Franco Fernanda Catharino Menezes , Nascimento Ivana Lúcia de Oliveira , Salomão Milene de Freitas Lima , Araujo Telma Martins de
Published: April 2009

INTRODUÇÃO: durante o tratamento ortodôntico, um processo inflamatório é induzido, desencadeando uma série de eventos bioquímicos que resultam na movimentação dentária. Estímulos como a hipóxia e a deformação mecânica são os principais fatores responsáveis pela quebra da homeostasia celular, resultando em estresse e liberação de diversos mediadores importantes para o movimento do dente. Para que a remodelação óssea ocorra durante o tratamento ortodôntico, fatores reguladores,como subprodutos do ácido araquidônico e citocinas,são liberados.Ao interferon gama (INF-γ , uma citocina principal liberada após a indução da resposta imune adaptativa, é atribuída a função de atrair os macrófagos, que auxiliam na remoção de restos celulares e promovem a cicatrização e reorganização das áreas com inflamação. OBJETIVO: visto que alguns aspectos biológicos que permeiam a movimentação dentária ainda não estão totalmente esclarecidos, procurou-se, neste trabalho, verificar a expressão do INF-γ por células do periodonto de ratos submetidos à movimentação ortodôntica. MÉTODOS: a amostra foi constituída por nove ratos, cujos primeiros molares superiores direitos foram movimentados com uma força de 0,5N, por 3, 7 e 14 dias. Os molares esquerdos desempenharam o papel de grupo controle. RESULTADOS: através da imunohistoquímica, foi verificada a ausência de expressão de INF-γ na quase totalidade dos tecidos estudados,tanto no lado de pressão quanto no lado de tração.
Estudo in vitro da degradação da força de elásticos ortodônticos de látex sob condições dinâmicas
Authors: Moris Alexandre , Sato Kikuo , Facholli Adriano Francisco de Lucca , Nascimento José Euclides , Sato Fábio Ricardo Loureiro
Published: April 2009

OBJETIVO: analisar 3 tamanhos de elásticos ortodônticos de látex (1/8", 3/16" e 5/16"), todos classificados como de força pesada pelos seus fabricantes (Dental Morelli, 3M Unitek Corporation e American Orthodontics). MÉTODOS: através de um dispositivo desenvolvido, os elásticos foram distendidos a 26mm (simulação da posição de repouso da mandíbula) e imersos em saliva artificial a uma temperatura de 37ºC. A cada minuto foram alongados a 44mm (simulação de movimentos mandibulares) e após 1 segundo voltavam a 26mm. Foram realizadas leituras em intervalos de tempos variados. Nos períodos considerados como horários das refeições (3 vezes ao dia), os elásticos eram retirados do dispositivo e guardados em uma caixa acrílica; e, no período considerado noturno, o dispositivo pneumático era desligado e os elásticos ficavam estirados em 26mm. RESULTADOS: a degradação maior da força ocorreu nas primeiras 2 horas para toda a amostra. CONCLUSÕES: concluiu-se que os elásticos apresentaram diferenças estatisticamente significativas em relação à espessura e à largura; e que os elásticos 1/8" devem ser trocados, pelo menos, a cada 24 horas e os elásticos 3/16" e 5/16" podem ser trocados a cada 72 horas, caso se deseje níveis de força próximos aos iniciais.
O modelo e-Score de previsão de falências para empresas de internet
Authors: Pereira Orlando Mansur , Ness Jr Walter Lee
Published: April 2009

Este estudo propõe um modelo de regressão logística que estime a probabilidade do evento de falência em empresas de Internet, isto é, as que sejam dependentes do e-business. Foram selecionadas 61 empresas norte-americanas e divididas em duas amostras: 25 empresas falidas, entre 1999 e 2001, e 36 não-falidas, no mesmo período. Uma amostra de treinamento foi aleatoriamente selecionada para a determinação das variáveis e dos parâmetros do modelo. A amostra de teste confirmou a alta acurácia do modelo, classificando corretamente 95,1% da amostra de 61 empresas, utilizando as demonstrações financeiras anuais do ano anterior à falência; e 88,1%, para demonstrações de 2 anos antes do mesmo evento. Portanto, o Modelo e-Score demonstra ser bastante significante utilizando apenas três variáveis, de 63 analisadas: (i) INT/TL: Interest Expense (Income) / Total Liabilities; (ii) R&D/EMP: Research & Development Expenses / Nº de Empregados; e (iii) OCF/CL: Operating Cash Flow / Current Liabilities. As variáveis (i) e (iii) são obtidas nas demonstrações convencionais, enquanto (ii) é inovadora, indicando que uma empresa de Internet que investe em R&D por empregado possui maiores chances de sobreviver. Já as que possuem Resultados Financeiros negativos altos e Fluxos de Caixa Operacionais baixos possuem menos chances de sobrevivência.
Diversity and seasonality of fruit flies (Diptera: Tephritidae and Lonchaeidae) and their parasitoids (Hymenoptera: Braconidae and Figitidae) in orchards of guava, loquat and peach
Authors: Souza-Filho MF. , Raga A. , Azevedo-Filho JA. , Strikis PC. , Guimarães JA. , Zucchi RA.
Published: April 2009

This work was carried out in orchards of guava progenies, and loquat and peach cultivars, in Monte Alegre do Sul, SP, Brazil, in 2002 and 2003. Guavas and loquats were bagged and unbagged bi-weekly and weekly, respectively, for assessment of the infestation period. Peach was only bagged weekly. The assays started when the fruits were at the beginning of development, but still green. Ripe fruits were taken to the laboratory and placed individually into plastic cups. McPhail plastic traps containing torula yeast were hung from January 2002 to January 2004 to assess the fruit fly population in each orchard, but only the Ceratitis capitata population is here discussed. Five tephritid species were reared from the fruits: Anastrepha bistrigata Bezzi, A. fraterculus (Wiedemann), A. obliqua (Macquart), A. sororcula Zucchi, and C. capitata, in addition to six lonchaeid species: Neosilba certa (Walker), N. glaberrima (Wiedemann), N. pendula (Bezzi), N. zadolicha McAlpine and Steyskal, Neosilba sp. 4, and Neosilba sp. 10 (both species are in the process of being described by P. C. Strikis), as well as some unidentified Neosilba species. Ten parasitoid species were obtained from fruit fly puparia, of which five were braconids: Asobara anastrephae (Muesebeck), Doryctobracon areolatus (Szépligeti), D. brasiliensis (Szépligeti), Opius bellus Gahan, and Utetes anastrephae (Viereck), and five figitids: Aganaspis pelleranoi (Brèthes), Dicerataspis grenadensis Ashmead, Lopheucoila anastrephae (Rhower), Leptopilina boulardi (Barbotin, Carlton and Kelner-Pillaut), and Trybliographa infuscata Diaz, Gallardo and Uchôa. Ceratitis capitata showed a seasonal behavior with population density peaking at the second semester of each year. Anastrepha and Neosilba species remained in the orchards throughout both years.
Application of Actinobacterial and Fungal Morphology on the Design of
Operating Strategies in Bioprocess Development
Authors: Panda T. , Rameshaiah G.N.
Published: April 2009

Various options in biotechnology have been exercised to produce industrially important metabolites from filamentous
organisms. To select a suitable production strategy, the direct and indirect roles of morphological parameters in
controlling bioprocess variables are observed. Some progress has been made in quantitation of morphology.Useful correlations
have been reported in the literature in this avenue. Of course, some of the models, with proper modification, can be
used to explain the morphological phenomena. This review is concerned with the application of morphological variables
to correlate with bioprocess parameters for explaining optimal production strategy.
Similarity Hypotheses for the Atmospheric Surface Layer Expressed by Non-Dimensional Characteristic Invariants – A Review
Authors: Kramm Gerhard , Herbert Fritz
Published: April 2009

In this paper, similarity hypotheses for the atmospheric surface layer (ASL) are reviewed using nondimensional characteristic invariants, referred to as π-numbers. The basic idea of this dimensional π-invariants analysis (sometimes also called Buckingham’s π-theorem) is described in a mathematically generalized formalism. To illustrate the task of this powerful method and how it can be applied to deduce a variety of reasonable solutions by the formalized procedure of non-dimensionalization, various instances are represented that are relevant to the turbulence transfer across the ASL and prevailing structure of ASL turbulence. Within the framework of our review we consider both (a) Monin- Obukhov scaling for forced-convective conditions, and (b) Prandtl-Obukhov-Priestley scaling for free-convective conditions. It is shown that in the various instances of Monin-Obukhov scaling generally two π-numbers occur that result in corresponding similarity functions. In contrast to that, Prandtl-Obukhov-Priestley scaling will lead to only one π number
in each case usually considered as a non-dimensional universal constant.

Since an explicit mathematical relationship for the similarity functions cannot be obtained from a dimensional π- invariants analysis, elementary laws of π-invariants have to be pointed out using empirical or/and theoretical findings. To evaluate empirical similarity functions usually considered within the framework flux-profile relationships, so-called integral similarity functions for momentum and sensible heat are presented and assessed on the basis of the friction velocity and the vertical component of the eddy flux densities of sensible and latent heat directly measured during the GREIV I 1974 field campaign.
THINKING ABOUT THE FUTURE: A PSYCHOLOGICAL ANALYSIS
Authors: Tonn Bruce E. , Conrad Fred
Published: April 2009

In this paper, the relationships between three endogenous variables – thinking about, worrying about, and imagining the future – and the relationships between these variables and a rich set of exogenous variables were explored. Data were collected via a web-based survey
using a sample of convenience; 572 individuals from 24 different countries completed the survey. The results suggest that respondents think about the near-term future frequently and about the long-term future not at all frequently. Additionally, individuals who are better able to imagine the
future think about the future more than those who cannot imagine the future well. Those who worry more about the future tend to think more about the future than those who do not. Older individuals think about the future less than younger individuals even though age is not correlated with worrying
about or imagining the future. Christians think more about the future than others although they also tend to worry less about the future. Secularists are less able to imagine the future. Individuals who are worried about major issues like global warming tend to think more about the future.
The results suggest that training individuals to better imagine potential futures could give them more confidence to think more and worry less about their futures.
Prevalence of Hip Symptoms and Radiographic and Symptomatic Hip Osteoarthritis in African Americans and Caucasians: The Johnston County Osteoarthritis Project
Authors: JORDAN JOANNE M. , HELMICK CHARLES G. , RENNER JORDAN B. , LUTA GHEORGHE , DRAGOMIR ANCA D. , WOODARD JANICE , FANG FANG , SCHWARTZ TODD A. , NELSON AMANDA E. , ABBATE LAUREN M. , CALLAHAN LEIGH F. , KALSBEEK WILLIAM D. , HOCHBERG MARC C.
Published: April 2009

Objective.

To report contemporary estimates of the prevalence of hip-related osteoarthritis (OA) outcomes in African Americans and Caucasians aged ≥ 45 years.

Methods.

Weighted prevalence estimates and their corresponding 95% confidence intervals for hip symptoms, radiographic hip OA, symptomatic hip OA, and severe radiographic hip OA were calculated using SUDAAN® for age, race, and sex subgroups among 3068 participants (33% African Americans, 38% men) in the baseline examination (1991–97) of The Johnston County Osteoarthritis Project, a population-based study of OA in North Carolina. Radiographic hip OA was defined as Kellgren-Lawrence radiographic grade ≥ 2, moderate/severe radiographic hip OA as grades 3 and 4, and symptomatic hip OA as hip symptoms in a hip with radiographic OA.

Results.

Hip symptoms were present in 36%; 28% had radiographic hip OA; nearly 10% had symptomatic hip OA; and 2.5% had moderate/severe radiographic hip OA. Prevalence of all 4 outcomes was higher in older individuals; most outcomes were higher for women and African Americans.

Conclusion.

African Americans in this population do not have a lower prevalence of hip-related OA outcomes as previous studies suggested. Increasing public and health system awareness of the relatively high prevalence of these outcomes, which can be disabling, may help to decrease their effects and ultimately prevent them.
Pervasive Learning System Based on a Scenario Model Integrating Web Service Retrieval and Orchestration
Authors: Pham Cuong Ngyuen , Garlatti Serge , Lau Simon , Barbry Benjamin , Vantroys Thomas
Published: April 2009

We are interested in learning and working scenarios integrating web service retrieval and orchestration in pervasive TEL systems in a learning situation at workplace. This paper proposes a context-aware model of corporate learning and working scenarios in e-retail environment such as shops and hypermarkets. This scenario model enables us to select how to achieve activities according to the current situation. We outline the semantic description of web services to enable the selection, composition and execution of web services to achieve objectives specified by learning and working activities. We propose a context-aware and adaptive model for pervasive learning systems. This model enables the selection of the relevant methods or services to realize activities according to the current situation. Moreover, we also build and develop an Intelligent Selling Space (ISS) architecture that serves as an infrastructure for service management and execution in e-retail environment.
Rabbit Polyclonal Mouse Antithymocyte Globulin Administration Alters Dendritic Cell Profile and Function in NOD Mice to Suppress Diabetogenic Responses
Authors: Huang Yanfei , Parker Matthew , Xia Changqing , Peng Ruihua , Wasserfall Clive , Clarke Tracy , Wu Lizhen , Chowdhry Tayseer , Campbell-Thompson Martha , Williams John , Clare-Salzler Michael , Atkinson Mark A. , Womer Karl L.
Published: April 2009

Mouse antithymocyte globulin (mATG) prevents, as well as reverses, type 1 diabetes in NOD mice, through mechanisms involving modulation of the immunoregulatory activities of T lymphocytes. Dendritic cells (DC) play a pivotal role in the generation of T cell responses, including those relevant to the autoreactive T cells enabling type 1 diabetes. As Abs against DC are likely generated during production of mATG, we examined the impact of this preparation on the phenotype and function of DC to elucidate novel mechanisms underlying its beneficial activities. In vivo, mATG treatment transiently induced the trafficking of mature CD8− predominant DC into the pancreatic lymph node of NOD mice. Splenic DC from mATG-treated mice also exhibited a more mature phenotype characterized by reduced CD8 expression and increased IL-10 production. The resultant DC possessed a potent capacity to induce Th2 responses when cultured ex vivo with diabetogenic CD4+ T cells obtained from BDC2.5 TCR transgenic mice. Cotransfer of these Th2-deviated CD4+ T cells with splenic cells from newly diabetic NOD mice into NOD.RAG−/− mice significantly delayed the onset of diabetes. These studies suggest the alteration of DC profile and function by mATG may skew the Th1/Th2 balance in vivo and through such actions, represent an additional novel mechanism by which this agent provides its beneficial activities.
Brief Residence at the Plasma Membrane of the MHC Class I-Related Chain B Is Due to Clathrin-Mediated Cholesterol-Dependent Endocytosis and Shedding
Authors: Agüera-González Sonia , Boutet Philippe , Reyburn Hugh T. , Valés-Gómez Mar
Published: April 2009

Recognition of MHC class I-related chain (MIC) molecules on the surface of target cells by the activating receptor NKG2D leads to their lysis by immune effector cells. Up-regulation of NKG2D ligands is broadly related to stress, although the detailed molecular mechanisms that control the presence of these molecules at the plasma membrane are unclear. To investigate the posttranslational mechanisms that control surface expression of the human NKG2D ligand MICB, we studied the subcellular localization and trafficking of this molecule. We found that in several cellular systems, the expression of MICB molecules on the cell surface is accompanied by an intracellular accumulation of the molecule in the trans-Golgi network and late endosome-related compartments. Surprisingly, MICB has a much shorter half-life at the plasma membrane than MHC molecules and this depends on both recycling to internal compartments and shedding to the extracellular medium. Internalization of MICB depends partially on clathrin, but importantly, the lipid environment of the membrane also plays a crucial role in this process. We suggest that the brief residence of MICB at the plasma membrane modulates, at least in part, the function of this molecule in the immune system.
Drak2 Is Upstream of p70S6 Kinase: Its Implication in Cytokine-Induced Islet Apoptosis, Diabetes, and Islet Transplantation
Authors: Mao Jianning , Luo Hongyu , Han Bing , Bertrand Richard , Wu Jiangping
Published: April 2009

Drak2 is a member of the death-associated protein family and a serine threonine kinase. In this study, we investigated its role in β cell survival and diabetes. Drak2 mRNA and protein were rapidly induced in islet β cells after stimulation by inflammatory lymphokines known to be present in type 1 diabetes. Drak2 up-regulation was accompanied by increased β cell apoptosis. β cell apoptosis caused by the said stimuli was inhibited by Drak2 knockdown using small interfering RNA. Conversely, transgenic Drak2 overexpression led to aggravated β cell apoptosis triggered by the stimuli. Further in vivo experiments demonstrated that Drak2 transgenic islets were more vulnerable to streptozocin insult. We established that inducible NO synthase was upstream and caspase-9 was downstream of Drak2 in its signaling pathway. Purified Drak2 could phosphorylate ribosomal protein S6 (p70S6) kinase in an in vitro kinase assay. Drak2 overexpression in NIT-1 cells led to enhanced p70S6 kinase phosphorylation, whereas Drak2 knockdown in these cells reduced it. These mechanistic studies proved that p70S6 kinase was a bona fide Drak2 substrate.
N-Glycosylation Enhances Presentation of a MHC Class I-Restricted Epitope from Tyrosinase
Authors: Ostankovitch Marina , Altrich-VanLith Michelle , Robila Valentina , Engelhard Victor H.
Published: April 2009

We recently demonstrated that the mechanism of processing of an HLA-A*0201-restricted peptide epitope, Tyr369(D), derived from the membrane protein tyrosinase, involves retrotranslocation of glycosylated molecules from the endoplasmic reticulum to the cytosol, removal of an N-linked carbohydrate from Asn371 by peptide N-glycanase, proteolysis by the proteasome and other proteases, and retransport of the resulting peptides into the endoplasmic reticulum for association with HLA-A*0201. Carbohydrate removal results in deamidation of Asn371 to aspartic acid. The asparagine-containing homolog of this peptide, Tyr369(N), is not presented by tyrosinase-expressing cells, and this has been presumed to be due to quantitative glycosylation of Asn371. Although examining cytosolic intermediates that accumulated in human melanoma cells treated with proteasome inhibitors, we were surprised to find both molecules that had been deglycosylated by peptide N-glycanase and a large number of molecules that had not been previously glycosylated. The failure of Tyr369(N) to be processed and presented from these latter molecules may be partially due to a process of deamidation independent of glycosylation. However, we also established that proteasomes degrade tyrosinase molecules that are still glycosylated, giving rise to a set of discrete intermediates that are not observed when unglycosylated molecules are degraded. We propose that Tyr369(N) fails to be presented because unglycosylated tyrosinase is degraded rapidly and relatively nonselectively. In contrast, glycosylation alters the selectivity of tyrosinase processing by the proteasome, enhancing the production or survival of Tyr369(D).
A Novel Hybrid Yeast-Human Network Analysis Reveals an Essential Role for FNBP1L in Antibacterial Autophagy
Authors: Huett Alan , Ng Aylwin , Cao Zhifang , Kuballa Petric , Komatsu Masaaki , Daly Mark J. , Podolsky Daniel K. , Xavier Ramnik J.
Published: April 2009

Autophagy is a conserved cellular process required for the removal of defective organelles, protein aggregates, and intracellular pathogens. We used a network analysis strategy to identify novel human autophagy components based upon the yeast interactome centered on the core yeast autophagy proteins. This revealed the potential involvement of 14 novel mammalian genes in autophagy, several of which have known or predicted roles in membrane organization or dynamics. We selected one of these membrane interactors, FNBP1L (formin binding protein 1-like), an F-BAR-containing protein (also termed Toca-1), for further study based upon a predicted interaction with ATG3. We confirmed the FNBP1L/ATG3 interaction biochemically and mapped the FNBP1L domains responsible. Using a functional RNA interference approach, we determined that FNBP1L is essential for autophagy of the intracellular pathogen Salmonella enterica serovar Typhimurium and show that the autophagy process serves to restrict the growth of intracellular bacteria. However, FNBP1L appears dispensable for other forms of autophagy induced by serum starvation or rapamycin. We present a model where FNBP1L is essential for autophagy of intracellular pathogens and identify FNBP1L as a differentially used molecule in specific autophagic contexts. By using network biology to derive functional biological information, we demonstrate the utility of integrated genomics to novel molecule discovery in autophagy.
Activin A Promotes the TGF-β-Induced Conversion of CD4+CD25− T Cells into Foxp3+ Induced Regulatory T Cells
Authors: Huber Samuel , Stahl Felix R. , Schrader Jörg , Lüth Stefan , Presser Katrin , Carambia Antonella , Flavell Richard A. , Werner Sabine , Blessing Manfred , Herkel Johannes , Schramm Christoph
Published: April 2009

TGF-β induces the conversion of CD4+CD25− T cells into CD4+CD25+Foxp3+ regulatory T cells (Treg). Activin A is a pleiotropic TGF-β family member and is expressed in response to inflammatory signals. In this study, we report on the effects of activin A on the conversion of CD4+CD25− T cells into Foxp3-expressing induced Treg (iTreg). Activin A was able to promote the conversion of CD4+CD25− T cells into iTreg in a dose-dependent manner in vitro. Activin A together with TGF-β1 had synergistic effects on the rate of iTreg conversion in vitro. Intact TGF-β1 signaling seemed to be essential for the effects of activin A on iTreg generation because cells overexpressing a dominant negative TGF-β type II receptor could not be converted by activin A in vitro. In vivo, the frequency of peripheral, but not central, Treg was increased in transgenic mice with elevated activin A serum levels and the in vivo conversion rate of CD4+CD25− T cells into Foxp3-expressing iTreg was increased as compared with wild type mice. These data suggest a role for activin A as a promoter of the TGF-β dependent conversion of CD4+CD25− T cells into iTreg in vitro and in vivo. Therefore, besides promoting inflammation, activin A may contribute to the regulation of inflammation via the expansion of peripheral Treg.
Cutting Edge: A Critical Role of B and T Lymphocyte Attenuator in Peripheral T Cell Tolerance Induction
Authors: Liu Xikui , Alexiou Maria , Martin-Orozco Natalia , Chung Yeonseok , Nurieva Roza I. , Ma Li , Tian Qiang , Kollias George , Lu Sijie , Graf Daniel , Dong Chen
Published: April 2009

T cell activation and tolerance are delicately regulated by costimulatory molecules. Although B and T lymphocyte attenuator (BTLA) has been shown as a negative regulator for T cell activation, its role in peripheral T cell tolerance induction in vivo has not been addressed. In this study, we generated a novel strain of BTLA-deficient mice and used three different models to characterize the function of BTLA in controlling T cell tolerance. In an oral tolerance model, BTLA-deficient mice were found resistant to the induction of T cell tolerance to an oral Ag. Moreover, compared with wild-type OT-II cells, BTLA−/− OT-II cells were less susceptible to tolerance induction by a high-dose OVA peptide administered i.v. Finally, BTLA−/− OT-I cells caused autoimmune diabetes in RIP-mOVA recipient mice. Our results thus demonstrate an important role for BTLA in the induction of peripheral tolerance of both CD4+ and CD8+ T cells in vivo.
Differential Requirements for Protection against Mucosal Challenge withFrancisella tularensisin the Presence versus Absence of Cholera Toxin B and InactivatedF. tularensis
Authors: Bitsaktsis Constantine , Rawool Deepak B. , Li Ying , Kurkure Nitin V. , Iglesias Bibiana , Gosselin Edmund J.
Published: April 2009

Francisella tularensis is a category A biothreat agent for which there is no approved vaccine and the correlates of protection are not well understood. In particular, the relationship between the humoral and cellular immune response to F. tularensis and the relative importance of each in protection is controversial. Yet, understanding this relationship will be crucial to the development of an effective vaccine against this organism. We demonstrate, for the first time, a differential requirement for humoral vs cellular immunity in vaccine-induced protection against F. tularensis infection, and that the requirement for Ab observed in some protection studies, may be overcome through the induction of enhanced cellular immunity. Specifically, following intranasal/mucosal immunization of mice with inactivated F. tularensis organisms plus the cholera toxin B subunit, we observe increased production of IgG2a/2c vs IgG1 Ab, as well as IFN-γ, indicating induction of a Th1 response. In addition, the requirement for F. tularensis-specific IgA Ab production, observed in studies following immunization with inactivated F. tularensis alone, is eliminated. Thus, these data indicate that enhanced Th1 responses can supersede the requirement for anti-F. tularensis-specific IgA. This observation also has important ramifications for vaccine development against this organism.
Acidic Mammalian Chitinase Regulates Epithelial Cell Apoptosis via a Chitinolytic-Independent Mechanism
Authors: Hartl Dominik , He Chuan Hua , Koller Babara , Da Silva Carla A. , Kobayashi Yasushi , Lee Chun Geun , Flavell Richard A. , Elias Jack A.
Published: April 2009

Acidic mammalian chitinase (AMCase) is produced during and plays an important role in the pathogenesis of Th2-mediated diseases and antiparasite responses. However, the effector responses of AMCase in these settings have not been adequately defined and the relationship(s) between its chitinolytic and other biologic properties have not been investigated. In these studies, we demonstrate that AMCase protects airway epithelial cells from Fas ligand- and growth factor withdrawal-induced apoptosis. This cytoprotection was associated with Akt phosphorylation and abrogated when the PI3K/Akt pathway was inhibited. Comparable cytoprotection was also seen in experiments comparing wild-type AMCase and mutant AMCase that lacked chitinolytic activity. Importantly, the apoptosis-inhibiting effect of enzymatically active and inactive AMCase was abrogated by treatment with allosamidin. These studies demonstrate that secreted AMCase feeds back in an autocrine and/or paracrine manner to protect pulmonary epithelial cells from growth factor withdrawal- and Fas ligand-induced apoptosis. They also demonstrate that the cytoprotection is mediated via a PI3K/Akt-dependent and allosamidin-sensitive pathway that is independent of the chitinolytic activity of this chitinase.
CD30 Is Required for CCL21 Expression and CD4 T Cell Recruitment in the Absence of Lymphotoxin Signals
Authors: Bekiaris Vasileios , Gaspal Fabrina , Kim Mi-Yeon , Withers David R. , McConnell Fiona M. , Anderson Graham , Lane Peter J. L.
Published: April 2009

Lymphoid tissue inducer cells express a diverse array of tumor necrosis family ligands, including those that bind CD30 and the lymphotoxin β receptor. Both of these signaling pathways have been linked with B/T segregation in the spleen. In this study, we have dissected a lymphotoxin-independent CD30-dependent signal for the induction of expression of the T zone chemokine, CCL21. Reduced expression of CCL21 due to CD30 deficiency was functionally significant: mice deficient in both lymphotoxin and CD30 (dKO) signals had significantly smaller accumulations of lymphocytes in their splenic white pulp areas, with no evidence of focal aggregation of T cells. Furthermore, recruitment of wild-type CD4 T cells was poor in dKO mice compared with both wild-type or lymphotoxin-deficient mice. Phylogeny suggests that CD30 signals predated those through the lymphotoxin β receptor. We suggest that CD30 signals from lymphoid tissue inducer cells were a primitive mechanism to recruit and prime CD4 T cells. This would have been a stepping stone in the evolution of the highly organized lymphotoxin dependent B and T white pulp areas within which CD4-dependent memory Ab responses now develop.
NK Cell Responsiveness Is Tuned Commensurate with the Number of Inhibitory Receptors for Self-MHC Class I: The Rheostat Model
Authors: Joncker Nathalie T. , Fernandez Nadine C. , Treiner Emmanuel , Vivier Eric , Raulet David H.
Published: April 2009

Inhibitory receptors that engage self-MHC class I molecules enable NK cells to detect disease-associated loss of MHC class I on surrounding cells. Previous studies showed that some NK cells lack all receptors for self-MHC class I, yet fail to exhibit autoimmunity because they are generally hyporesponsive to stimulation. We asked whether NK cells exist in only two states, responsive and hyporesponsive, corresponding to cells that express or fail to express inhibitory receptors for self-MHC class I. The alternative model is that NK cells vary continuously in their responsiveness, based on variations in the number of different inhibitory and stimulatory receptors they express, which is known to vary. In this study, we show in the murine system that NK cell responsiveness increases quantitatively with each added self-MHC-specific inhibitory receptor. Genetic analysis demonstrated that interactions of each of the receptors with self-MHC class I were necessary to observe augmented responsiveness. These findings suggest that NK cell responsiveness is comparable to a rheostat: it is tuned to an optimal set point depending on the inhibitory and stimulatory interactions encountered in the normal environment, so as to ensure self-tolerance and yet optimize sensitivity to changes in normal cells.
Host-Derived Interleukin-1α Is Important in Determining the Immunogenicity of 3-Methylcholantrene Tumor Cells
Authors: Elkabets Moshe , Krelin Yakov , Dotan Shahar , Cerwenka Adelheid , Porgador Angel , Lichtenstein Rachel G. , White Malka R. , Zoller Margot , Iwakura Yoichizo , Dinarello Charles A. , Voronov Elena , Apte Ron N.
Published: April 2009

Using IL-1/IL-1Ra knockout BALB/c mice, we showed that 3-methylcholatrene (3-MCA)-induced carcinogenesis is dependent on IL-1β-induced inflammatory responses. Patterns of local inflammation and tumorigenicity were similar in wild-type (WT) and IL-1α−/− mice, while in IL-1β−/− mice, tumorigenicity was attenuated and in IL-1Ra−/− mice accentuated. 3-MCA-induced fibrosarcoma cell lines from WT mice developed into progressive tumors in WT mice, while surprisingly, lines from IL-1α−/− mice formed tumors only in immunocompromized mice. 3-MCA-induced fibrosarcoma cell lines from IL-1α−/− mice, compared with lines from WT mice, manifested higher expression levels of “global” surface molecules related to Ag presentation and interactions with immune surveillance cells (MHC class I, B7.1, B7.2, L-selectin, and NKG2D ligands) and were eradicated mainly by CD4+- and CD8+-dependent T cell responses. Concomitantly, at the injection site of 3-MCA-induced fibrosarcoma cells derived from IL-1α−/− mice, a leukocyte infiltrate, subsequently replaced by a scar-like tissue, was observed. Immune aberrations in NK cell maturation, antitumor specific immunity and killing capacity of effector cells were observed in IL-1α−/− mice, in contrast to WT mice. Thus, we demonstrate in this study the significance of host-derived IL-1α in cancer immunoediting, by affecting innate and specific immunosurveillance mechanisms. Overall, the results presented in this study, together with our previous studies, attest to differential involvement of IL-1α and IL-1β in tumorigenesis; host-derived IL-1β mainly controls inflammation, while concomitantly, IL-1α controls immunosurveillance of the arising malignant cells. Elucidation of the involvement of the IL-1 molecules in the malignant process will hopefully lead to the development of novel approaches for chemoprevention and immunotherapy.
Protective Response to Leishmania major in BALB/c Mice Requires Antigen Processing in the Absence of DM
Authors: Kamala Tirumalai , Nanda Navreet K.
Published: April 2009

Protection from the parasite Leishmania major is mediated by CD4 T cells. BALB/c mice are susceptible to L. major and show a nonprotective immunodominant CD4 T cell response to Leishmania homolog of activated receptor for c-kinase (LACK) 158–173. Host genes that underlie BALB/c susceptibility to L. major infections are poorly defined. DM, a nonclassical MHC class II molecule, due to its peptide editing properties has been shown to 1) edit the repertoire of peptides displayed by APC, and 2) focus the display of epitopes by APC to the immunodominant ones. We tested the hypothesis that deficiency of DM, by causing presentation of a different array of epitopes by infected APC than that presented by DM-sufficient APC, may change the course of L. major infection in the susceptible BALB/c mice. We show herein that unlike their susceptible wild-type counterparts, BALB/c mice deficient in DM are protected from infections with L. major. Furthermore, DM-deficient mice fail to display the immunodominant LACK 158–173 on infected APC. In its place, infected DM−/− hosts show elicitation of CD4 T cells specific for newer epitopes not presented by wild-type L. major-infected APC. Protection of BALB/c DM−/− mice is dependent on IFN-γ. DM is thus a host susceptibility gene in BALB/c mice, and Ag processing in the absence of DM results in elicitation of a protective T cell response against L. major infections. This report suggests a novel mechanism to trigger host resistance against pathogens.
Natural Lipid Ligands Associated with Human CD1d Targeted to Different Subcellular Compartments
Authors: Yuan Weiming , Kang Suk-Jo , Evans James E. , Cresswell Peter
Published: April 2009

CD1d is an MHC class I-like membrane glycoprotein that presents lipid Ags to NKT cells. Despite intensive biochemical, genetic, and structural studies, the endogenous lipids associated with CD1d remain poorly defined because of the biochemical challenges posed by their hydrophobic nature. In this study, we report the generation of a protease-cleavable CD1d variant with a similar trafficking pattern to wild-type CD1d that can be purified in the absence of detergent and allows the characterization of the naturally associated lipids. In addition, we used soluble variants of CD1d that are secreted or retained in the endoplasmic reticulum (ER) to survey their acquired lipids. By using multiple mass spectrometry methods, we found that CD1d retained in the ER is predominantly loaded with the most abundant phospholipid in the cell, phosphatidyl choline, while the protease cleavable version of CD1d contains bound sphingomyelin and lysophospholipids in addition to phosphatidyl choline. The secreted soluble version of CD1d, in contrast, lacks detectable phosphatidyl choline and the only detectable associated lipid is sphingomyelin. The data suggest that, in the absence of infection or stress, CD1d molecules survey the ER, the secretory pathway, and the endocytic pathway, and accumulate the most abundantly available lipids present in these compartments.
Statins Impair CD1d-Mediated Antigen Presentation through the Inhibition of Prenylation
Authors: Khan Masood A. , Gallo Richard M. , Renukaradhya Gourapura J. , Du Wenjun , Gervay-Hague Jacquelyn , Brutkiewicz Randy R.
Published: April 2009

Statins are widely used as cholesterol-lowering agents that also decrease inflammation and target enzymes essential for prenylation, an important process in the activation and intracellular transport of proteins vital for a wide variety of cellular functions. Here, we report that statins impair a critical component of the innate immune response, CD1d-mediated Ag presentation. The addition of specific intermediates in the isoprenylation pathway reversed this effect, whereas specific targeting of enzymes responsible for prenylation mimicked the inhibitory effects of statins on Ag presentation by CD1d as well as MHC class II molecules. This study demonstrates the importance of isoprenylation in the regulation of Ag presentation and suggests a mechanism by which statins reduce inflammatory responses.
Thymic OX40 Expression Discriminates Cells Undergoing Strong Responses to Selection Ligands
Authors: Klinger Mark , Kim Joong Kyu , Chmura Stephen A. , Barczak Andrea , Erle David J. , Killeen Nigel
Published: April 2009

OX40 is a member of the TNF receptor family expressed on activated and regulatory T (Treg) cells. Using an Ox40-cre allele for lineage marking, we found that a subpopulation of naive T cells had also previously expressed OX40 in the thymus. Ox40-cre was induced in a small fraction of thymocytes that were OX40+, some of which were CD25high Treg cell precursors. Thymic OX40 expression distinguished cells experiencing a strong signaling response to positive selection. Naive T cells that had previously expressed OX40 demonstrated a partially activated phenotype that was distinct from that of most naive T cells. The results are consistent with the selection of Treg cells and a minor subpopulation of naive T cells being dependent on strong signaling responses to thymic self ligands.
Cutting Edge: Lung Mucosal Th17-Mediated Responses Induce Polymeric Ig Receptor Expression by the Airway Epithelium and Elevate Secretory IgA Levels
Authors: Jaffar Zeina , Ferrini Maria E. , Herritt Lou A. , Roberts Kevan
Published: April 2009

Polymeric Ig receptor (pIgR) is a central player in mucosal immunity that mediates the delivery of polymeric IgA and IgM to the apical surface of epithelial cells via transcytosis. Emerging evidence suggests that Th17 cells not only mediate autoimmunity but also play key roles in mucosal host defense against pathogens. We demonstrate that OVA-specific CD4+ Th17 cells, in addition to causing neutrophilic inflammation in mice, mediated a pronounced influx of CD19+ B cells into the lungs following Ag inhalation. Coincident with this recruitment was a striking induction in pIgR expression by the bronchial epithelium and a subsequent increase in airway IgM and secretory IgA levels. Intranasal administration of IL-17 revealed a crucial role for this cytokine in inducing pIgR expression by the epithelium. These findings support a key role for Th17 cells in pulmonary immune defense against respiratory pathogens by promoting pIgR-mediated transport of secretory IgA and IgM into the airway.
Catégoriser à 13 et 16 mois : comparaison de deux méthodes
Authors: Bourdais Cécile , Pêcheux Marie-Germaine
Published: April 2009

Résumé On compare ici deux tâches, l’exploration multimodale et le toucher séquentiel, communément utilisées pour étudier la catégorisation chez des enfants préverbaux (13 et 16 mois). Divers types de catégorisation ont été suggérés aux enfants en présentant des reproductions en plastique d’animaux et de voitures : des catégories taxonomiques (Rosch, Mervis, Gray, Johnson et Boyes-Braem., 1976) du niveau de base, surordonnées et subordonnées, et des catégories contextuelles (Mandler & Bauer, 1988). Pour l’exploration multimodale on a repris la méthodologie de Oakes, Plumert, Lansink et Merryman (1996), i.e. une familiarisation à 4 items avec 12 essais, suivie de tests de réaction à la nouveauté pour un nouvel exemplaire de la catégorie, et deux nouveaux items hors catégorie. Les mêmes items ont été présentés dans la tâche de toucher séquentiel, chaque plateau incluant 4 items de 2 catégories contrastées. Les résultats confirment que la catégorisation apparaît plus précocement au travers de l’exploration multimodale, pour tous les types de catégories. L’ordre de difficulté des catégories est le même pour les deux tâches et les deux âges : surordonnées d’abord, puis subordonnées, puis du niveau de base puis contextuelles. Enfin aucun effet de l’âge n’est observé. Dans la discussion on s’interroge sur l’effet des savoirs préalables dans l’une et l’autre tâche. Par ailleurs, dans la mesure où les deux tâches utilisent l’attention comme indice de l’activité cognitive, on suggère que les caractéristiques de l’attention au début de la seconde année doivent être prises en compte pour expliquer les performances.
Bending of the Flexible Spacer Chain of Gemini Surfactant Induced by Hydrophobic Interaction
Authors: YOU Yi , JIANG Rong , LING Tingting , ZHAO Jianxi
Published: April 2009

In order to understand the special role of the flexible alkylene spacer of gemini surfactant in the self‐assembly, three gemini surfactants, alkylene‐α,ω‐bis(didodecylmethylammonium bromide) that is designated as 2C12‐s‐2C12· 2Br (s=3, 6, 8), were synthesized. When the spread films of 2C12‐s‐2C12·2Br on the surface of water were constructed, they form the dense layer of the alkyl tails owing to four dodecyl chains per molecule. This induced the bending of the spacer chain toward the air‐side at the s smaller than that of C12‐s‐C12·2Br adsorbed on the air/water interface owing to the enhanced hydrophobic interaction between the alkyl tails and the spacer chain, where C12‐s‐C12·2Br has only two alkyl tails per molecule. Conclusively, the enhanced hydrophobic interaction between the alkyl tails and the spacer chain can effectively induce the bending of the latter toward the air‐side.
Synthesis of covalently linked porphyrin dimers and trimers
Authors: Anton John A. , Kwong Josephine , Loach Paul A.
Published: April 2009

The synthesis of covalently linked porphyrin dimers and trimers is described. Mono‐ and dihydroxyporphyrins were synthesized by transeslerifying 5,10,15,20‐tetra(4‐carbomethoxy‐phenyl)porphyrin with ethylene glycol. The mixture of transesterified porphyrins were separated by preparative thin layer chromatography. Metal derivatives were made of the mono‐ and dihydroxyporphyrins and these were reacted with the acid chloride of a monocarboxyporphyrin to yield hybrid dimers and trimers containing one melalloporphyrin and either one or two free base porphyrins. The structures and purity of the dimers and trimers were established by measuring the absorbance spectra, nmr spectra, and molecular weight by gel permeation chromatography.
Trapping of thiaziridinimines with thiocarbonyl compounds
Authors: L'Abbé Gerrit , Yu Chih‐Chou
Published: April 2009

Thermolysis of 4‐benzyl‐5‐tosylimino‐1,2,3,4‐thiatriazoline at 60–70° in the presence of representative C = S unsaturated compounds furnished 1,2,4‐dithiazolidin‐5‐imines in moderate yields. The reaction is assumed to proceed via the inlermediacy of an unstable thiaziridinimine which is trapped by the C=S compound in a regiospecific manner. Among the thiocarbonyl compounds used are p,p′‐dimethoxythiobenzophenone, xanthates and 3‐benzylrhodanine, the latter giving rise to a spiro adduct.
Dem Kohlenstoff im Meer auf der Spur
Authors: Dittmar Thorsten
Published: April 2009

Etwa 60 Petamol Kohlenstoff sind in den Ozeanen als gelöstes organisches Material gespeichert. Mit hochauflösender Massenspektrometrie lässt sich seine Zusammensetzung analysieren. Dies hilft, den globalen Kohlenstoffkreislauf besser zu verstehen.
Mechanische Eigenschaften mit Obertonanalyse: FT‐Rheologie
Authors: Wilhelm Manfred
Published: April 2009

Die Fourier‐Transform‐Rheologie erweitert die oszillierende Rheologie in den nichtlinearen Bereich. Das ist der Bereich, in dem Viskosität und Elastizität eine Funktion der Anregung werden, die Messung also das Material verändert. Somit liefert die Methode Informationen zum mechanischen Verhalten, die praxisrelevante Eigenschaften oft besser widerspiegeln als lineare Daten.
Organisch‐chemische Rückstandsanalyse in der Arktis
Authors: Kallenborn Roland , Trümper Monika
Published: April 2009

Schadstoffkonzentrationen in arktischen Proben sind in der Regel sehr gering. Die niedrigen Konzentrationen in Kombination mit dem großen Kontaminationspotenzial während Probennahme und Lagerung konfrontieren den Umweltforscher mit besonderen methodischen Schwierigkeiten. Fachfremde Wissenschaftler müssen daher alle Messresultate kritisch hinterfragen, bevor sie diese interpretieren. Die Analysenmethoden sind nach den Kriterien der Qualitätssicherung zu validieren.
Onlineanalytik verbessert Prozessführung
Authors: Krämer Stefan , Wegner Horst
Published: April 2009

Konventionelle Regelung arbeitet mit Messungen von Durchfluss, Druck und Temperatur. Messdaten aus Onlineanalytik liefern stoffspezifische Informationen wie Konzentrationen und entstammen einer komplexeren Messtechnik.
Und sie bewegen sich doch
Authors: Fischer Lars
Published: April 2009

Wie effektiv töten Softdrinks Spermien? Untersuchung eines ungewöhnlichen Verhütungsmittels.
Preparation of HMX by Perfluorooctanesulfonic Acid Catalyzed Nitrolysis of Hexamethylenetetramine in Fluorous Media
Authors: Yi Wen‐Bin , Cai Chun
Published: April 2009

Perfluorooctanesulfonic acid (CF3(CF2)7SO3H, PFOS) efficiently catalyzes the nitrolysis of hexamethylenetetramine in fluorous media, affording a good yield of the explosive HMX. The reaction can be carried out without acetic anhydride or acetic acid. The fluorous phase containing the catalyst could be easily separated and can be reused several times without significant loss of catalytic activity.