A Student-Centered, Entrepreneurship Development (ASCEND) Undergraduate Summer Research Program: Foundational Training for Health Research.

Increasing the participation of students of African descent and other minoritized populations in the scientific workforce is imperative in generating a more equitable biomedical research infrastructure and increasing national research creativity and productivity. Undergraduate research training programs have shown to be essential tools in retaining underrepresented minority (URM) students in the sciences and attracting them into STEM and biomedical careers. This paper describes an innovative approach to harness students' entrepreneurial desire for autonomy and creativity in a Summer Research Institute (SRI) that has served as an entry point into a multiyear, National Institutes of Health Building Infrastructure Leading to Diversity (NIH BUILD)-funded research training program.

Trapping of a cross-link formed by a major purine adduct of a metabolite of the carcinogen N-nitrosomorpholine by inorganic and biological reductants.

3-Hydroperoxy-N-nitrosomorpholine in buffered aqueous media in the presence of calf thymus DNA was treated with a phosphine reductant to generate the transient α-hydroxynitrosamine and subsequent diazonium ion that alkylated the DNA, as previously reported. Subsequent addition of hydride donors, for 30 min, followed by acid hydrolysis of the mixture allowed detection and quantification of 6-(2-{2-[(9H-purin-6-yl)amino]ethoxy}ethoxy)-9H-purin-2-amine, the reduced cross-link formed from deposition, via the diazonium ion, of a 3-oxapentanal fragment on O(6)-Gua, and condensation with N(6)-Ade, presumably in the vicinity. Decreasing the temperature of the reaction mixtures and decreasing the pH modestly increased the yields of the trapped cross-link.

Lactone metabolite common to the carcinogens dioxane, diethylene glycol, and N-nitrosomorpholine: aqueous chemistry and failure to mediate liver carcinogenesis in the F344 rat.

1,4-Dioxan-2-one, 1, was synthesized, and the equilibrium constant between it and the hydrolysis product 2-(2-hydroxyethoxy) acetic acid, 2, was determined as K(O) = 70 ± 4 in acidic aqueous media, 25 °C, ionic strength 1 M (KCl), and 5% by volume acetonitrile. The carboxylic acid dissociation constant of 2 was determined under the same conditions to be pK(a) = 3.31 ± 0.

Synthesis of modified nucleosides for incorporation of formyletheno and carboxyetheno adducts of adenine nucleosides into oligonucleotides.

Three protected derivatives of 1,N(6)-ethenoadenine nucleosides, viz. 3-[5-O-(4,4'-dimethoxytrityl) of 7-formyl-(1) and 7-(1,2-diacetyloxypropyl)-2'-deoxyadenosine (2), and 3-[5-O-(4,4'-dimethoxytrityl)-2-O-(tert-butyldimethylsilyl)-7-(ethoxycarbonyl)adenosine (3), expected to allow introduction of formyletheno and carboxyethenoadenine adducts into oligonucleotides by the conventional phosphoramidite chemistry, have been synthesized.

Reactions of 9-substituted guanines with bromomalondialdehyde in aqueous solution predominantly yield glyoxal-derived adducts.

Reactions of 9-ethylguanine, 2'-deoxyguanosine and guanosine with bromomalondialdehyde in aqueous buffers over a wide pH-range were studied. The main products were isolated and characterized by (1)H and (13)C NMR and mass spectroscopy. The final products formed under acidic and basic conditions were different, but they shared the common feature of being derived from glyoxal.

Synthesis of an oligonucleotide analogue of ethenoadenosine.

A phosphoramidite building block derived from 11-carboxy-1,N6-ethenoadenosine has been prepared to be used in a solid supported oligonucleotide synthesis.