Unique pathogen peptidomes facilitate pathogen-specific selection and specialization of MHC alleles

A key component of pathogen-specific adaptive immunity in vertebrates is the presentation of pathogen-derived antigenic peptides by major histocompatibility complex (MHC) molecules. The excessive polymorphism observed at MHC genes is widely presumed to result from the need to recognize diverse pathogens, a process called pathogen-driven balancing selection. This process assumes that pathogens differ in their peptidomes—the pool of short peptides derived from the pathogen’s proteome—so that different pathogens select for different MHC variants with distinct peptide-binding properties. Here, we tested this assumption in a comprehensive data set of 51.9 Mio peptides, derived from the peptidomes of 36 representative human pathogens. Strikingly, we found that 39.7\% of the 630 pairwise comparisons among pathogens yielded not a single shared peptide and only 1.8\% of pathogen pairs shared more than 1\% of their peptides. Indeed, 98.8\% of all peptides were unique to a single pathogen species. Using computational binding prediction to characterize the binding specificities of 321 common human MHC class-I variants, we investigated quantitative differences among MHC variants with regard to binding peptides from distinct pathogens. Our analysis showed signatures of specialization toward specific pathogens especially by MHC variants with narrow peptide-binding repertoires. This supports the hypothesis that such fastidious MHC variants might be maintained in the population because they provide an advantage against particular pathogens. Overall, our results establish a key selection factor for the excessive allelic diversity at MHC genes observed in natural populations and illuminate the evolution of variable peptide-binding repertoires among MHC variants

A coincidence point theorem for multi-valued contractions

A coincidence point theorem for two pairs of mappings is proved

Systematic Search of Exactly Solvable Non-Central Potentials

Recently developed supersymmetric perturbation theory has been successfully employed to make a complete mathematical analysis the reason behind exact solvability of some non-central potentials. This investigation clarifies once more the effectiveness of the present formalism.Comment: 7 pages, no figure

Impact of global climate change on agricultural production: Balkan countries in 2050

The occurrence of extreme weather events due to today’s climate change is having a significant impact on agriculture. The purpose of this study is to estimate the possible effects of global climate change on agriculture at a regional level. To this end, the Global trade analyses project (GTAP) model has been used to examine the possible effects of climate change on agricultural production in Turkey, Romania, Bulgaria, Greece, and other Balkan countries for 2050. GTAP analysis data is compiled from the GTAP database, which includes 6 regions and 33 sectors. It has been calculated that climate change will have negative effects on the gross domestic product (GDP) of Balkan countries. The negative impact of global climate change on crop yields is predicted to reduce the competitiveness of Balkan countries in the foreign trade of agricultural products. © 2020, Scibulcom Ltd.. All rights reserved

Supersymmetric approach to exactly solvable systems with position-dependent effective masses

We discuss the relationship between exact solvability of the Schr\"{o}dinger equation with a position-dependent mass and the ordering ambiguity in the Hamiltonian operator within the frame of supersymmetric quantum mechanics. The one-dimensional Schr\"{o}dinger equation, derived from the general form of the effective mass Hamiltonian, is solved exactly for a system with exponentially changing mass in the presence of a potential with similar behaviour, and the corresponding supersymmetric partner Hamiltonians are related to the effective-mass Hamiltonians proposed in the literature.Comment: 12 pages article in LaTEX (uses standard article.sty). Please check http://www1.gantep.edu.tr/~ozer for other studies of Nuclear Physics Group at University of Gaziantep. [arXiv admin note: excessive overlap with quant-ph/0306065 and "Supersymmetric approach to quantum systems with position-dependent effective mass" by A. R. Plastino, A. Rigo, M. Casas, F. Garcias, and A. Plastino - Phys. Rev. A 60, 4318 - 4325 (1999)

An Upper Bound on the Higgs Boson Mass from a Positivity Condition on the Mass Matrix

We impose the condition that the eigenvalues of the mass matrix in the shifted Lagrangian density be positive at \phi=\phi_{0}, the vacuum expectation value of the scalar field. Using the one-loop effective potential of the standard model, this condition leads to an upper bound on the Higgs boson mass m_{H}: m_{H}<230GeV, for a top quark mass of 175GeV.Comment: LaTex, 5 page

European Society for Sexual Medicine position statement 'Assessment and hormonal management in adolescent and adult trans people, with attention for sexual function and satisfaction'

Background: There is a general lack of recommendations for and basic information tailored at sexologists and other health-care professionals for when they encounter trans people in their practice. Aim: We present to clinicians an up-to-date overview of clinical consensus statements on trans health care with attention for sexual function and satisfaction. Methods: The task force consisted of 7 clinicians experienced in trans health care, selected among European Society for Sexual Medicine (ESSM) scientific committee. The consensus was guided by clinical experience and a review of the available literature and by interactive discussions on trans health, with attention for sexual function and satisfaction where available. Outcomes: The foci of the study are assessment and hormonal aspects of trans health care. Results: As the available literature for direct recommendations was limited, most of the literature was used as background or indirect evidence. Clinical consensus statements were developed based on clinical experiences and the available literature. With the multiple barriers to care that many trans people experience, basic care principles still need to be stressed. We recommend that health-care professionals (HCPs) working with trans people recognize the diversity of genders, including male, female, and nonbinary individuals. In addition, HCPs assessing gender diverse children and adolescents should take a developmental approach that acknowledges the difference between prepubescent gender diverse children and pubescent gender diverse adolescents and trans adults. Furthermore, trans people seeking gender-affirming medical interventions should be assessed by HCPs with expertise in trans health care and gender-affirming psychological practice. If masculinization is desired, testosterone therapy with monitoring of serum sex steroid levels and signs of virilization is recommended. Similarly, if feminization is desired, we recommend estrogens and/or antiandrogen therapy with monitoring of serum sex steroid levels and signs of feminization. HCPs should be aware of the influence of hormonal therapy on sexual functioning and satisfaction. We recommend HCPs be aware of potential sexual problems during all surgical phases of treatment. Clinical Implications: This is an up-to-date ESSM position statement. Strengths & Limitations: These statements are based on the data that are currently available; however, it is vital to recognize that this is a rapidly changing field and that the literature, particularly in the field of sexual functioning and satisfaction, is limited. Conclusion: This ESSM position statement provides relevant information and references to existing clinical guidelines with the aim of informing relevant HCPs on best practices when working with transgender people

Targeted analysis of polymorphic loci from low-coverage shotgun sequence data allows accurate genotyping of HLA genes in historical human populations

The highly polymorphic human leukocyte antigen (HLA) plays a crucial role in adaptive immunity and is associated with various complex diseases. Accurate analysis of HLA genes using ancient DNA (aDNA) data is crucial for understanding their role in human adaptation to pathogens. Here, we describe the TARGT pipeline for targeted analysis of polymorphic loci from low-coverage shotgun sequence data. The pipeline was successfully applied to medieval aDNA samples and validated using both simulated aDNA and modern empirical sequence data from the 1000 Genomes Project. Thus the TARGT pipeline enables accurate analysis of HLA polymorphisms in historical (and modern) human populations