Richard A. Kjonaas

Conjugate addition to α,β-unsaturated ketones with mixed lithium triorganozincates

Abstract Lithium Triorganozincates of the type RR′ 2 ZnLi, where R′ = Me and R = n -Bu or sec-Bu, efficiently transfer the R group in a 1,4 fashion to α,β-unsaturated ketones.

Phytol-based novel adjuvants in vaccine formulation: 1. assessment of safety and efficacy during stimulation of humoral and cell-mediated immune responses

This is a correction article.

Phytol-based novel adjuvants in vaccine formulation: 2. assessment of efficacy in the induction of protective immune responses to lethal bacterial infections in mice

BackgroundAdjuvants are known to significantly enhance vaccine efficacy. However, commercial adjuvants often have limited use because of toxicity in humans. The objective of this study was to determine the comparative effectiveness of a diterpene alcohol, phytol and its hydrogenated derivative PHIS-01, relative to incomplete Freunds adjuvant (IFA), a commonly used adjuvant in augmenting protective immunity in mice against E. coli and S. aureus, and in terms of inflammatory cytokines.MethodsVaccines, consisting of heat-attenuated E. coli or S. aureus and either of the two phytol-based adjuvants or IFA, were tested in female BALB/c mice. The vaccines were administered intraperitoneally at 10-day intervals. The efficacy of the phytol and PHIS-01, as compared to IFA, was assessed by ELISA in terms of anti-bacterial antibody and inflammatory cytokines. We also examined the ability of the vaccines to induce specific protective immunity by challenging mice with different doses of live bacteria.Results and discussionIFA, phytol, and PHIS-01 were equally efficient in evoking anti-E. coli antibody response and in providing protective immunity against live E. coli challenges. In contrast, the antibody response to S. aureus was significant when PHIS-01 was used as the adjuvant. However, in terms of the ability to induce protective immunity, phytol was most effective against S. aureus. Moreover, during challenges with live E. coli and S. aureus immune mice produced much less IL-6, the mediators of fatal septic shock syndromes.ConclusionOur results show that vaccine formulations containing phytol and PHIS-01 as adjuvants confer a robust and protective immunity against both Gram-negative and Gram-positive bacteria without inducing adverse inflammatory cytokine due to IL-6.

Does N-hydroxyglycine inhibit plant and fungal laccases?

Abstract The effect of N -hydroxyglycine on the oxidation of substrates, syringaldazine, tolidine, 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) and 2,6-dimethoxyphenol, by fungal and plant laccases was examined. At μM concentrations, N -hydroxyglycine decolorized solutions of substrates oxidized enzymatically by laccase or chemically by sodium periodate. This discoloration, or bleaching, could be mistaken for inhibition of laccase activity if N-hydroxyglycine was added to assays for laccase that monitored colored products. N -hydroxyglycine also affected oxygen consumption assays when some of these substrates were oxidized enzymatically or chemically. Spectral scans of the products formed during enzymatic or chemical oxidation of the substrates indicated that addition of N -hydroxyglycine caused a general decrease in absorption. Except for 2,6-dimethoxyphenol, no formation of new absorption peaks was noted. These results suggest that N -hydroxyglycine may not be a “classical” enzyme inhibitor of laccase, but that this compound interferes with both spectrophotometric and oxygen uptake enzyme assays for laccase.

Dilithio acetoacetate as an acetone enolate equivalent

Abstract Dilithio acetoacetate, which can be generated from acetoacetic acid and n-butyllithium, undergoes alkylation followed by facile decar☐ylation to give methyl ketones.

A source of isomer-drawing assignments

A comprehensive source from which instructors can choose a wide variety of good isomer drawing examples to use as homework assignments and exam questions.