Features of medullary thymic epithelium implicate postnatal development in maintaining epithelial heterogeneity and tissue-restricted antigen expression.
Authors:Gillard GO, Farr AG
Journal:J Immunol
PubMed ID:16670287
'Although putative thymic epithelial progenitor cells have been identified, the developmental potential of these cells, the extent of medullary thymic epithelium (mTEC) heterogeneity, and the mechanisms that mediate the expression of a wide range of peripheral tissue-restricted Ags (TRAs) by mTECs remain poorly defined. Here we have defined several basic ... More
Biotinylated photocleavable polyethylenimine: capture and triggered release of nucleic acids from solid supports.
Authors:Handwerger RG, Diamond SL
Journal:Bioconjug Chem
PubMed ID:17432825
'A biotinylated photocleavable polyethylenimine (B-PC-PEI) was designed and synthesized for the capture and controlled release of nucleic acids from solid supports. B-PC-PEI was synthesized via a three-step reaction process and verified by 1H NMR and mass spectrometry. In aqueous solution, the o-nitrobenzyl group within B-PC-PEI was efficiently cleaved by 5 ... More
Development of a SYBR safe technique for the sensitive detection of DNA in cesium chloride density gradients for stable isotope probing assays.
Authors:Martineau C, Whyte LG, Greer CW,
Journal:J Microbiol Methods
PubMed ID:18329741
SYBR safe, a fluorescent nucleic acid stain, was evaluated as a replacement for ethidium bromide (EtBr) in cesium chloride (CsCl) density gradients for DNA stable isotope probing (DNA-SIP) assays. The separation of 12C- and 13C-labelled DNA using SYBR safe gave similar results to those obtained using EtBr with pure cultures ... More
Single step protocol to purify recombinant proteins with low endotoxin contents.
Authors:Reichelt P, Schwarz C, Donzeau M
Journal:Protein Expr Purif
PubMed ID:16290005
Endotoxin is an unwanted by product of recombinant proteins purified from Escherichia coli. The inherent toxicity of endotoxins makes their removal an important step for the proteins' application in several biological assays and for safe parenteral administration. The method described in this paper is a one-step protocol which is effective ... More
5-Methyltetrahydrofolate inhibits photosensitization reactions and strand breaks in DNA.
Authors:Offer T, Ames BN, Bailey SW, Sabens EA, Nozawa M, Ayling JE
Journal:FASEB J
PubMed ID:17341682
The known functions of folate are to support one-carbon metabolism and to serve as photoreceptors for cryptochromes and photolyases. We demonstrate that 5-methyltetrahydrofolate (5-MTHF, the predominant folate in plasma) is also a potent, near diffusion limited, scavenger of singlet oxygen and quencher of excited photosensitizers. Both pathways result in decomposition ... More