A number of yeast species can transform ricinoleic acid into γ-decalactone, a high-value compound with fruity aroma, through β-oxidation. This study investigated the effect of l-carnitine on γ-decalactone production by Saccharomyces cerevisiae MF013 to increase the β-oxidation rate. Results showed that l-carnitine shortened the biotransformation period by approximately 10 h and increased γ-decalactone production by 19.5%. γ-Caprolactone, γ-octalactone, and γ-dodecalactone were separately added to the medium to prevent γ-decalactone degradation by yeast cells at the end of biotransformation. γ-Octalactone competitively inhibited γ-decalactone from binding to lactonase, resulting in an 11% increase in γ-decalactone production. This research proposed an effective approach to improve the γ-decalactone production rate, shorten the biotransformation period, and suppress the γ-decalactone degradation in S. cerevisiae.

Human norovirus (HuNoV) is a food-borne pathogen that causes acute gastroenteritis in people of all ages worldwide. However, no approved vaccines and antiviral drugs are available at present. Therefore, the development of accurate and rapid detection technologies is important in controlling the outbreak of HuNoVs. This paper reviewed the research progress on HuNoV detection, including immunological methods, molecular detection and biosensor technology. Immunological methods and molecular detection technologies are still widely used for HuNoV detection. Furthermore, biosensors will become an emerging developmental direction for the rapid detection of HuNoVs because of their high sensitivity, low cost, easy operation and suitability for onsite detection.

Human Noroviruses (HuNoVs) are the main cause of nonbacterial gastroenteritis. Contaminated produce is a main vehicle for dissemination of HuNoVs. In this study, we used an ice nucleation protein mediated surface display system to present the protruding domain of GII.4 HuNoV capsid protein on bacterial surface and used it as a new strategy to explore interaction between HuNoV protein and receptor candidates from romaine lettuce. The surface-displayed HuNoV proteins were confirmed on the surface of the transformed bacteria by an immunofluorescence assay. The distribution patterns of the surface-displayed HuNoV proteins in romaine lettuce were identified through a confocal immunofluorescence assay. The surface-displayed HuNoV proteins could be found in the stomata, and the surfaces of vein and leaf of romaine lettuce. The surface-displayed HuNoV proteins could be captured by an ELISA assay utilizing extract from leaf (LE) or vein (VE). The binding of the surface-displayed HuNoV proteins to LE or VE could be competitively blocked by histo-blood group antigens from human saliva. In addition, the binding of the surface-displayed HuNoV proteins to LE or VE could also be attenuated by heat denaturation of lettuce proteins, and abolished by oxidation of lettuce carbohydrates. The results indicated that histo-blood group antigen-like molecules in LE or VE were involved in the binding of the surface-displayed HuNoV proteins to romaine lettuce. All data demonstrated that the surface-displayed HuNoV proteins could be utilized in a new and simple system for investigation of the interaction between the HuNoVs and their candidate ligands.