493 research outputs found
Phototriggered release of tetrapeptide AAPV from coumarinyl and pyrenyl cages
Ala-Ala-Pro-Val (AAPV) is a bioactive tetrapeptide that inhibits human neutrophil elastase (HNE), an enzyme involved in skin chronic inflammatory diseases like psoriasis. Caged derivatives of this peptide were prepared by proper N- and C-terminal derivatisation through a carbamate or ester linkage, respectively, with two photoactive moieties, namely 7-methoxycoumarin-2-ylmethyl and pyren-2-ylmethyl groups. These groups were chosen to assess the influence of the photosensitive group and the type of linkage in the controlled photorelease of the active molecule. The caged peptides were irradiated at selected wavelengths of irradiation (254, 300, and 350 nm), and the photolytic process was monitored by HPLC-UV. The results established the applicability of the tested photoactive groups for the release of AAPV, especially for the derivative bearing the carbamate-linked pyrenylmethyl group, which displayed the shortest irradiation times for the release at the various wavelengths of irradiation (ca. 4 min at 254 nm, 8 min at 300 nm and 46 min at 350 nm).Thanks are due to the Fundação para a Ciência e Tecnologia (FCT, Portugal) for
financial support to the portuguese NMR network (PTNMR, Bruker Avance III 400-
Univ. Minho), FCT and FEDER (European Fund for Regional Development)-
COMPETE-QREN-EU for financial support through the Chemistry Research Centre of
the University of Minho (Ref. UID/QUI/00686/2013 and UID/QUI/0686/2016). A PhD
grant to A.M.S. (SFRH/BD/80813/2011) is also acknowledged.info:eu-repo/semantics/publishedVersio
Effect of high energy X-ray irradiation on the nano-mechanical properties of human enamel and dentine
Correlation between nucleotide composition and folding energy of coding sequences with special attention to wobble bases
Background: The secondary structure and complexity of mRNA influences its
accessibility to regulatory molecules (proteins, micro-RNAs), its stability and
its level of expression. The mobile elements of the RNA sequence, the wobble
bases, are expected to regulate the formation of structures encompassing coding
sequences.
Results: The sequence/folding energy (FE) relationship was studied by
statistical, bioinformatic methods in 90 CDS containing 26,370 codons. I found
that the FE (dG) associated with coding sequences is significant and negative
(407 kcal/1000 bases, mean +/- S.E.M.) indicating that these sequences are able
to form structures. However, the FE has only a small free component, less than
10% of the total. The contribution of the 1st and 3rd codon bases to the FE is
larger than the contribution of the 2nd (central) bases. It is possible to
achieve a ~ 4-fold change in FE by altering the wobble bases in synonymous
codons. The sequence/FE relationship can be described with a simple algorithm,
and the total FE can be predicted solely from the sequence composition of the
nucleic acid. The contributions of different synonymous codons to the FE are
additive and one codon cannot replace another. The accumulated contributions of
synonymous codons of an amino acid to the total folding energy of an mRNA is
strongly correlated to the relative amount of that amino acid in the translated
protein.
Conclusion: Synonymous codons are not interchangable with regard to their
role in determining the mRNA FE and the relative amounts of amino acids in the
translated protein, even if they are indistinguishable in respect of amino acid
coding.Comment: 14 pages including 6 figures and 1 tabl
Transferrin uptake may occur through detergent-resistant membrane domains at the cytopharynx of Trypanosoma cruzi epimastigote forms
Проблемы увеличения продуктивности АПК в Украине и пути повышения его потенциала
Целью статьи является изучение причин снижения показателей продуктивности в агропромышленном комплексе и путей повышения продуктивности сельскохозяйственных культур
Detection of diploid males in a natural colony of the cleptobiotic bee Lestrimelitta sp (Hymenoptera, Apidae)
When working at quantifying the genome size of stingless bees, it was observed that males of Lestrimelitta sp possessed the same amount of nuclear DNA as the females. Thus, we used flow cytometry (FCM) and cytogenetic analysis to confirm the ploidy of these individuals. The males analyzed proved to be diploid, since, through cytometric analysis, it was demonstrated that the mean genome size of both males and females was the same (C = 0.463 pg), and, furthermore, cytogenetic analysis demonstrated that both had 2n = 28 chromosomes
Asteroseismology and Interferometry
Asteroseismology provides us with a unique opportunity to improve our
understanding of stellar structure and evolution. Recent developments,
including the first systematic studies of solar-like pulsators, have boosted
the impact of this field of research within Astrophysics and have led to a
significant increase in the size of the research community. In the present
paper we start by reviewing the basic observational and theoretical properties
of classical and solar-like pulsators and present results from some of the most
recent and outstanding studies of these stars. We centre our review on those
classes of pulsators for which interferometric studies are expected to provide
a significant input. We discuss current limitations to asteroseismic studies,
including difficulties in mode identification and in the accurate determination
of global parameters of pulsating stars, and, after a brief review of those
aspects of interferometry that are most relevant in this context, anticipate
how interferometric observations may contribute to overcome these limitations.
Moreover, we present results of recent pilot studies of pulsating stars
involving both asteroseismic and interferometric constraints and look into the
future, summarizing ongoing efforts concerning the development of future
instruments and satellite missions which are expected to have an impact in this
field of research.Comment: Version as published in The Astronomy and Astrophysics Review, Volume
14, Issue 3-4, pp. 217-36
Identification of Candidate Susceptibility and Resistance Genes of Mice Infected with Streptococcus suis Type 2
Streptococcus suis type 2 (SS2) is an important swine pathogen and zoonosis agent. A/J mice are significantly more susceptible than C57BL/6 (B6) mice to SS2 infection, but the genetic basis is largely unknown. Here, alterations in gene expression in SS2 (strain HA9801)-infected mice were identified using Illumina mouse BeadChips. Microarray analysis revealed 3,692 genes differentially expressed in peritoneal macrophages between A/J and B6 mice due to SS2 infection. Between SS2-infected A/J and control A/J mice, 2646 genes were differentially expressed (1469 upregulated; 1177 downregulated). Between SS2-infected B6 and control B6 mice, 1449 genes were differentially expressed (778 upregulated; 671 downregulated). These genes were analyzed for significant Gene Ontology (GO) categories and signaling pathways using the Kyoto Encylopedia of Genes and Genomes (KEGG) database to generate a signaling network. Upregulated genes in A/J and B6 mice were related to response to bacteria, immune response, positive regulation of B cell receptor signaling pathway, type I interferon biosynthesis, defense and inflammatory responses. Additionally, upregulated genes in SS2-infected B6 mice were involved in antigen processing and presentation of exogenous peptides, peptide antigen stabilization, lymphocyte differentiation regulation, positive regulation of monocyte differentiation, antigen receptor-mediated signaling pathway and positive regulation of phagocytosis. Downregulated genes in SS2-infected B6 mice played roles in glycolysis, carbohydrate metabolic process, amino acid metabolism, behavior and muscle regulation. Microarray results were verified by quantitative real-time PCR (qRT-PCR) of 14 representative deregulated genes. Four genes differentially expressed between SS2-infected A/J and B6 mice, toll-like receptor 2 (Tlr2), tumor necrosis factor (Tnf), matrix metalloproteinase 9 (Mmp9) and pentraxin 3 (Ptx3), were previously implicated in the response to S. suis infection. This study identified candidate genes that may influence susceptibility or resistance to SS2 infection in A/J and B6 mice, providing further validation of these models and contributing to understanding of S. suis pathogenic mechanisms
Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV
The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration
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