ABSTRACT
BACKGROUND: Exposure to microbes and their components may affect the maturation of the immune system. We examined the association of house dust microbial content with cytokine-producing capacity at birth and at the age of 1 year. METHODS: Production of TNF-α, IFN-γ, IL-5, IL-8 and IL-10 at birth (n = 228) and at the age of 1 year (n = 200) following 24- and 48-hour whole-blood stimulation with staphylococcal enterotoxin B (SEB), lipopolysaccharide and the combination of phorbol ester and ionomycin was measured. Concentrations of ergosterol (marker for fungal biomass), muramic acid (marker for Gram-positive bacteria) and 3-hydroxy fatty acids with a carbon chain length from 10 to 14 (marker for Gram-negative bacteria) in living room floor dust were analyzed using gas chromatography-tandem mass spectrometry. Five single microbial species or groups were determined using a quantitative polymerase chain reaction method. RESULTS: A high total level of the studied Gram-positive bacteria in general or Mycobacterium spp. in house dust was associated with decreased SEB-stimulated IFN-γ production, especially at the age of 1 year. The total level of indoor fungi analyzed (Penicillium spp., Aspergillus spp. and Paecilomyces variotii group, Trichoderma viride/atroviride/koningii,Wallemia sebi) was also inversely associated with IFN-γ production at the age of 1 year, but this association did not remain significant after adjustment for potential confounders. A few associations were found between microbial exposures and other measured cytokines. CONCLUSIONS: High indoor microbial exposures may affect immune development in early life by reducing T helper type 1 cytokine secretion capacity. The observed hyporesponsiveness may reflect the adaptation of the immune system to environmental antigens. In future, more attention should be paid especially to the immunomodulatory role of exposures to Gram-positive bacteria.
Subject(s)
Air Microbiology , Cytokines/biosynthesis , Th1 Cells/immunology , Adaptation, Physiological , Bacterial Load , Cohort Studies , Colony Count, Microbial , Dust/immunology , Environmental Exposure , Female , Finland , Fungi/immunology , Fungi/isolation & purification , Gram-Positive Bacteria/immunology , Gram-Positive Bacteria/isolation & purification , Humans , Immune System/growth & development , Infant , Infant, Newborn , Male , Pregnancy , Prospective StudiesABSTRACT
An enzymatic transglycosylation of purine heterocyclic bases employing readily available natural nucleosides or sugar-modified nucleosides as donors of the pentofuranose fragment and recombinant nucleoside phosphorylases as biocatalysts has been investigated. An efficient enzymatic method is suggested for the synthesis of purine nucleosides containing diverse substituents at the C6 and C2 carbon atoms. The glycosylation of N(6)-benzoyladenine and N(2)-acetylguanine and its O(6)-derivatives is not accompanied by deacylation of bases.
Subject(s)
Purine-Nucleoside Phosphorylase/metabolism , Purines/chemistry , Purines/metabolism , Glycosylation , Molecular Structure , Purine Nucleosides/biosynthesis , Purine Nucleosides/chemistry , Recombinant Proteins/metabolism , ThermodynamicsABSTRACT
The crystal structures of the title compounds 1 and 2 have been determined. Relation between the stereochemistry of both nucleosides in the crystal state and the (1)H NMR data in solution as well as the ab initio calculations is discussed.
Subject(s)
Thymidine/analogs & derivatives , Circular Dichroism , Crystallography, X-Ray , Magnetic Resonance Spectroscopy , Models, Molecular , Molecular Conformation , Solutions , Thymidine/chemical synthesis , Thymidine/chemistryABSTRACT
A new method to produce a set of 20 high quality trinucleotide phosphoramidites on a 5-10 g scale each was developed. The procedure starts with condensation reactions of P-components with N-acyl nucleosides, bearing the 3 '-hydroxyl function protected with 2-azidomethylbenzoyl, to give fully protected dinucleoside phosphates 13. Upon cleavage of dimethoxytrityl group from 13, dinucleoside phosphates 16 are initially transformed into trinucleoside diphosphates 19 and then the 2-azidomethylbenzoyl is selectively removed under neutral conditions to generate trinucleoside diphosphates 5 in excellent yield. Subsequent 3 '-phosphitylation affords target trinucleotide phosphoramidites 7. When mutagenic oligonucleotides are synthesized employing mixtures of building blocks 7 as well as following the new synthetic protocol, representative oligonucleotide libraries are generated in good yields.
Subject(s)
Oligonucleotides/chemistry , Organophosphorus Compounds/chemical synthesis , Chromatography, High Pressure Liquid , Models, Chemical , Molecular Structure , Organophosphorus Compounds/chemistry , Spectrometry, Mass, Electrospray Ionization , Thionucleotides/chemistryABSTRACT
In the structure of the title compound, C11H13N5O4, the glycosidic torsion angle, chi, is -107.1 (2) degrees [nucleic acid nomenclature used throughout the manuscript; IUPAC-IUB Joint Commision on Biochemical Nomenclature (1983). Eur. J. Biochem. 131, 9-15], indicating the anti conformation. The furanosyl ring adopts an N-type sugar pucker with the following pseudorotational parameters: PN = 50.5 (2) degrees and nu max = 34.9 (1) degrees. The conformation around the C5'-C6' bond is ap (gauche,trans; gt; -g), with a torsion angle gamma of 176.28 (19) degrees. The 1',2'-oxetane ring is not planar but folded along C3'...C1', with an angle of 9.6 (1) degrees.
