74 research outputs found

    Clusters versus Affinity-Based Approaches in F. tularensis Whole Genome Search of CTL Epitopes

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    Deciphering the cellular immunome of a bacterial pathogen is challenging due to the enormous number of putative peptidic determinants. State-of-the-art prediction methods developed in recent years enable to significantly reduce the number of peptides to be screened, yet the number of remaining candidates for experimental evaluation is still in the range of ten-thousands, even for a limited coverage of MHC alleles. We have recently established a resource-efficient approach for down selection of candidates and enrichment of true positives, based on selection of predicted MHC binders located in high density “hotspots" of putative epitopes. This cluster-based approach was applied to an unbiased, whole genome search of Francisella tularensis CTL epitopes and was shown to yield a 17–25 fold higher level of responders as compared to randomly selected predicted epitopes tested in Kb/Db C57BL/6 mice. In the present study, we further evaluate the cluster-based approach (down to a lower density range) and compare this approach to the classical affinity-based approach by testing putative CTL epitopes with predicted IC50 values of <10 nM. We demonstrate that while the percent of responders achieved by both approaches is similar, the profile of responders is different, and the predicted binding affinity of most responders in the cluster-based approach is relatively low (geometric mean of 170 nM), rendering the two approaches complimentary. The cluster-based approach is further validated in BALB/c F. tularensis immunized mice belonging to another allelic restriction (Kd/Dd) group. To date, the cluster-based approach yielded over 200 novel F. tularensis peptides eliciting a cellular response, all were verified as MHC class I binders, thereby substantially increasing the F. tularensis dataset of known CTL epitopes. The generality and power of the high density cluster-based approach suggest that it can be a valuable tool for identification of novel CTLs in proteomes of other bacterial pathogens

    Self Assessment in Insects: Honeybee Queens Know Their Own Strength

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    Contests mediate access to reproductive opportunities in almost all species of animals. An important aspect of the evolution of contests is the reduction of the costs incurred during intra-specific encounters to a minimum. However, escalated fights are commonly lethal in some species like the honeybee, Apis mellifera. By experimentally reducing honeybee queens' fighting abilities, we demonstrate that they refrain from engaging in lethal contests that typically characterize their reproductive dominance behavior and coexist peacefully within a colony. This suggests that weak queens exploit an alternative reproductive strategy and provides an explanation for rare occurrences of queen cohabitation in nature. Our results further indicate that self-assessment, but not mutual assessment of fighting ability occurs prior to and during the agonistic encounters

    First Neutrino Observations from the Sudbury Neutrino Observatory

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    The first neutrino observations from the Sudbury Neutrino Observatory are presented from preliminary analyses. Based on energy, direction and location, the data in the region of interest appear to be dominated by 8B solar neutrinos, detected by the charged current reaction on deuterium and elastic scattering from electrons, with very little background. Measurements of radioactive backgrounds indicate that the measurement of all active neutrino types via the neutral current reaction on deuterium will be possible with small systematic uncertainties. Quantitative results for the fluxes observed with these reactions will be provided when further calibrations have been completed.Comment: Latex, 7 pages, 10 figures, Invited paper at Neutrino 2000 Conference, Sudbury, Canada, June 16-21, 2000 to be published in the Proceeding

    Classical and revisionary theism on the divine as personal: a rapprochement?

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    To claim that the divine is a person or personal is, according to Richard Swinburne, ‘the most elementary claim of theism’ (1993, 101). I argue that, whether the classical theist’s concept of the divine as a person or personal is construed as an analogy or a metaphor, or a combination of the two, analysis necessitates qualification of that concept such that any differences between the classical theist’s concept of the divine as a person or personal and revisionary interpretations of that concept are merely superficial. Thus, either the classical theist has more in common with revisionary theism than he/she might care to admit, or classical theism is a multi-faceted position which encompasses interpretations which some might regard as revisionist. This article also explores and employs the use of a gender-neutral pronoun in talk about God

    Whole-Genome Immunoinformatic Analysis of F. tularensis: Predicted CTL Epitopes Clustered in Hotspots Are Prone to Elicit a T-Cell Response

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    The cellular arm of the immune response plays a central role in the defense against intracellular pathogens, such as F. tularensis. To date, whole genome immunoinformatic analyses were limited either to relatively small genomes (e.g. viral) or to preselected subsets of proteins in complex pathogens. Here we present, for the first time, an unbiased bacterial global immunoinformatic screen of the 1740 proteins of F. tularensis subs. holarctica (LVS), aiming at identification of immunogenic peptides eliciting a CTL response. The very large number of predicted MHC class I binders (about 100,000, IC50 of 1000 nM or less) required the design of a strategy for further down selection of CTL candidates. The approach developed focused on mapping clusters rich in overlapping predicted epitopes, and ranking these “hotspot” regions according to the density of putative binding epitopes. Limited by the experimental load, we selected to screen a library of 1240 putative MHC binders derived from 104 top-ranking highly dense clusters. Peptides were tested for their ability to stimulate IFNγ secretion from splenocytes isolated from LVS vaccinated C57BL/6 mice. The majority of the clusters contained one or more CTL responder peptides and altogether 127 novel epitopes were identified, of which 82 are non-redundant. Accordingly, the level of success in identification of positive CTL responders was 17–25 fold higher than that found for a randomly selected library of 500 predicted MHC binders (IC50 of 500 nM or less). Most proteins (ca. 2/3) harboring the highly dense hotspots are membrane-associated. The approach for enrichment of true positive CTL epitopes described in this study, which allowed for over 50% increase in the dataset of known T-cell epitopes of F. tularensis, could be applied in immunoinformatic analyses of many other complex pathogen genomes

    Reduced Diversity and High Sponge Abundance on a Sedimented Indo-Pacific Reef System: Implications for Future Changes in Environmental Quality

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    Although coral reef health across the globe is declining as a result of anthropogenic impacts, relatively little is known of how environmental variability influences reef organisms other than corals and fish. Sponges are an important component of coral reef fauna that perform many important functional roles and changes in their abundance and diversity as a result of environmental change has the potential to affect overall reef ecosystem functioning. In this study, we examined patterns of sponge biodiversity and abundance across a range of environments to assess the potential key drivers of differences in benthic community structure. We found that sponge assemblages were significantly different across the study sites, but were dominated by one species Lamellodysidea herbacea (42% of all sponges patches recorded) and that the differential rate of sediment deposition was the most important variable driving differences in abundance patterns. Lamellodysidea herbacea abundance was positively associated with sedimentation rates, while total sponge abundance excluding Lamellodysidea herbacea was negatively associated with rates of sedimentation. Overall variation in sponge assemblage composition was correlated with a number of variables although each variable explained only a small amount of the overall variation. Although sponge abundance remained similar across environments, diversity was negatively affected by sedimentation, with the most sedimented sites being dominated by a single sponge species. Our study shows how some sponge species are able to tolerate high levels of sediment and that any transition of coral reefs to more sedimented states may result in a shift to a low diversity sponge dominated system, which is likely to have subsequent effects on ecosystem functioning. © 2014 Powell et al

    Vilnius Residents Lifestyle Features and Values

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    Nuolat vykstantis visuomeninių pokyčių procesas sukelia vertybių kaitą, atsisakoma tradicinių vertybių ir atrandamos naujos, keičiasi suvokimas ir poreikiai, todėl siekiant išsiaiškinti žmonių požiūrį į gyvenimo vertybes privaloma nuolat atlikti vertybių tyrimus. Tyrimo tikslas. Ištirti jaunų žmonių gyvenseną ir vertybes. Tyrime dalyvavo Vilniaus miesto 25–35 metų gyventojai, sutikę jame dalyvauti. Iš viso buvo apklausta 310 respondentų. Statistinė duomenų analizė atlikta naudojant SPSS 19.0 ir Microsoft Excel 2003 kompiuterines programas. Tik apie 30% tyrime dalyvavusių jaunų žmonių mano, kad vertybės yra svarbios šiuolaikinėje visuomenėje. Jauni žmonės svarbiausiomis gyvenimo vertybėmis laiko meilę, šeimą, sveikatą. Mažiausią svarbą užima tokios vertybės kaip kultūra ir tautiškumas. Nustatytas statistiškai reikšmingas skirtumas tarp vyrų ir moterų. Moterys yra labiau tikinčios, labiau vertina sveikatą, meilę, viltį, kultūrą ir tautiškumą. Tuo tarpu vyrams svarbesnės yra materialinės vertybės. Taip pat tyrimo metu buvo nustatytos vertybių sąsajos su sveikata. Tyrimas parodė, kad visuomenėje vyksta tam tikrų vertybių devalvacija. Labiausiai jaunų žmonių vertybes ir jų formavimąsi veikia draugai, šeima, mylimi žmonės. Žmonių požiūris į gyvenimo vertybes skiriasi priklausomai nuo lyties, išsilavinimo, šeimyninės padėties.Nowadays people needs and perception are changing very often. An ongoing process of life cause change of values, people refuse traditional values and discover the new values. To find out people’s views on life values it is recommended to carry out regular surveys. The aim of paper is to investigate and survey young people’s values. It was attended by 25-35 years old residents of the city of Vilnius. The questionnaire survey was carried out after have received the permission from the managers of companies. Were interviewed 310 respondents. Statistical analysis was performed using SPSS 19.0 and Microsoft Excel 2003 software programs. Only about 30% of young people surveyed believe that values are important in today’s society. The most important values by respondents is love, family and health. The least important values are culture and nationality. There is a statistically significant difference between men and women. Friends, family and close people mostly affect young people values and their creation. People’s attitudes to life values vary depending on gender, education, marital status
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