1. Organocatalytic asymmetric synthesis of β(3)-amino acid derivatives
Sun Min Kim, Jung Woon Yang Org Biomol Chem. 2013 Aug 7;11(29):4737-49. doi: 10.1039/c3ob40917a. Epub 2013 Jun 7.
β(3)-Amino acid derivatives are an essential resource for pharmaceutical production, medicinal chemistry, and biochemistry. In this article, recent developments in versatile organocatalysis, i.e., Brønsted acid catalysis, Brønsted base catalysis, Lewis acid catalysis, Lewis base catalysis, and phase-transfer catalysis, for the asymmetric synthesis of β(3)-amino acid derivatives will be presented.
2. Physiological Genomics of the Highly Weak-Acid-Tolerant Food Spoilage Yeasts of Zygosaccharomyces bailii sensu lato
Margarida Palma, Isabel Sá-Correia Prog Mol Subcell Biol. 2019;58:85-109. doi: 10.1007/978-3-030-13035-0_4.
Zygosaccharomyces bailii and two closely related species, Z. parabailii and Z. pseudobailii ("Z. bailii species complex", "Z. bailii sensu lato" or simply "Z. bailii (s.l.)"), are frequently implicated in the spoilage of acidified preserved foods and beverages due to their tolerance to very high concentrations of weak acids used as food preservatives. The recent sequencing and annotation of these species' genomes have clarified their genomic organization and phylogenetic relationship, which includes events of interspecies hybridization. Mechanistic insights into their adaptation and tolerance to weak acids (e.g., acetic and lactic acids) are also being revealed. Moreover, the potential of Z. bailii (s.l.) to be used in industrial biotechnological processes as interesting cell factories for the production of organic acids, reduction of the ethanol content, increase of alcoholic beverages aroma complexity, as well as of genetic source for increasing weak acid resistance in yeast, is currently being considered. This chapter includes taxonomical, ecological, physiological, and biochemical aspects of Z. bailii (s.l.). The focus is on the exploitation of physiological genomics approaches that are providing the indispensable holistic knowledge to guide the effective design of strategies to overcome food spoilage or the rational exploitation of these yeasts as promising cell factories.
3. The Stephan Curve revisited
William H Bowen Odontology. 2013 Jan;101(1):2-8. doi: 10.1007/s10266-012-0092-z. Epub 2012 Dec 6.
The Stephan Curve has played a dominant role in caries research over the past several decades. What is so remarkable about the Stephan Curve is the plethora of interactions it illustrates and yet acid production remains the dominant focus. Using sophisticated technology, it is possible to measure pH changes in plaque; however, these observations may carry a false sense of accuracy. Recent observations have shown that there may be multiple pH values within the plaque matrix, thus emphasizing the importance of the milieu within which acid is formed. Although acid production is indeed the immediate proximate cause of tooth dissolution, the influence of alkali production within plaque has received relative scant attention. Excessive reliance on Stephan Curve leads to describing foods as "safe" if they do not lower the pH below the so-called "critical pH" at which point it is postulated enamel dissolves. Acid production is just one of many biological processes that occur within plaque when exposed to sugar. Exploration of methods to enhance alkali production could produce rich research dividends.
