Buckleyhildebrandt9141

Antitubercular agent levesquamide is a new polyketide-nonribosomal peptide (PK-NRP) hybrid marine natural product isolated from Streptomyces sp. RKND-216. The structure contains a rare isothiazolinone moiety which has only been reported in collismycin SN. Structure elucidation by NMR spectroscopy was a significant challenge due to a deficiency of protons in this aromatic moiety. Therefore, the genome of Streptomyces sp. RKND-216 was sequenced to identify the levesquamide biosynthetic gene cluster (BGC). Analysis of the BGC provided structural insights and guided stable-isotope labeling experiments, which led to the assignment of the fused pyridine-isothiazolinone moiety. The BGC and the labeling experiments provide further insights into the biosynthetic origin of isothiazolinones. Levesquamide exhibited antimicrobial activity in the microplate alamarBlue assay (MABA) and low oxygen recovery assay (LORA) against Mycobacterium tuberculosis H37Rv with minimum inhibitory concentration (MIC) values of 9.65 and 22.28 μM, respectively. Similar activity was exhibited against rifampicin- and isoniazid-resistant M. tuberculosis strains with MIC values of 9.46 and 9.90 μM, respectively. This result suggests levesquamide has a different mode of action against M. tuberculosis compared to the two first-line antitubercular drugs rifampicin and isoniazid. Furthermore, levesquamide shows no cytotoxicity against the Vero cell line, suggesting it may have a useful therapeutic window.Lactococcus lactis subsp. lactis biovar diacetylactis is widely used in dairy fermentations as it can form the butter aroma compounds acetoin and diacetyl from citrate in milk. Here, we explore the possibility of producing acetoin from the more abundant lactose. Starting from a dairy isolate of L. lactis biovar diacetylactis, we obtained a series of mutants with low lactate dehydrogenase (ldh) activity. One isolate, RD1M5, only had a single insertion mutation in the ldh gene compared to its parental strain as revealed by whole genome resequencing. We tested the ability of RD1M5 to produce acetoin in milk. With aeration, all the lactose could be consumed, and the only product was acetoin. In a simulated cheese fermentation, a 50% increase in acetoin concentration could be achieved. RD1M5 turned out to be an excellent cell factory for acetoin and was able to convert lactose in dairy waste into acetoin with high titer (41 g/L) and high yield (above 90% of the theoretical yield). OPB-171775 molecular weight Summing up, RD1M5 was found to be highly robust and to grow excellently in milk or dairy waste. Being natural in origin opens up for applications within dairies as well as for safe production of food-grade acetoin from low-cost substrates.The physicochemical properties of ionic liquids can be readily controlled. Currently, it is necessary to investigate the properties of different surfactants to elucidate the mixtures used in quaternary-ammonium-salt-type ionic liquids. Herein, the surface adsorption and bulk properties of homogeneous polyoxyethylene (EO)-type nonionic surfactant, quaternary-ammonium-salt-type cationic surfactant, and sulfobetaine-type zwitterionic surfactant are elucidated in quaternary-ammonium-salt-type amphiphilic monomeric ionic liquids and gemini ionic liquids with bis(fluorosulfonyl)imide or bis(trifluoromethanesulfonyl)imide as counterions. The monomeric amphiphilic ionic liquids that adsorbed at the interface were replaced with CxEOy (where x and y represent alkyl and EO chain lengths, respectively) as the concentration of CxEOy increased. On the other hand, in the gemini amphiphilic ionic liquids, the surface tensions of CxEOy were lower than those of the monomeric ionic liquids. Consequently, both gemini amphiphilic ionic liquids and CxEOy adsorbed efficiently at the interface and oriented themselves because of a synergistic effect. Furthermore, for ionic liquids with short alkyl chains, an orderly bulk nanostructure was not observed at low concentrations in CxEOy, while a layer structure formed at higher concentrations; in contrast, ionic liquids with long alkyl chains formed a layer structure. The alkyl chains, which were interlocked in the bilayer structure, resulted in a densely packed layer structure.An efficient and practical one-pot strategy to produce highly substituted 1-naphthylamines via sequential palladium-catalyzed decarboxylative amination/intramolecular 6-endo-dig benzannulation reactions has been described. In this reaction, a broad range of electron-rich, electron-neutral, and electron-deficient o-alkynylarylketones react well with N-hydroxyl aryl/alkylamides to give a diversity of 1-naphthylamines in good to excellent yields under mild reaction conditions. The gram-scale synthesis, with benefits such as undiminished product yield and easy transformation, illustrated the practicality of this method.Sea-buckthorn flavonoids (SFs) have been used as functional food components for their bioactive potential in preventing metabolic complications caused by diet, such as obesity and inflammation. However, the protective effect of SFs on cognitive functions is not fully clear. In this study, a high-fat and high-fructose diet (HFFD)-induced obese mice model was treated with SFs for 14 weeks. It was found that the oral SF administration (0.06% and 0.31% w/w, mixed in diet) significantly reduced bodyweight gain and insulin resistance in the HFFD-fed mice. SFs significantly prevented HFFD-induced neuronal loss and memory impairment in behavioral tests. Additionally, SFs also suppressed the HFFD-induced synaptic dysfunction and neuronal damages by increasing the protein expressions of PSD-95. Furthermore, SF treatment activated the ERK/CREB/BDNF and IRS-1/AKT pathways and inactivated the NF-κB signaling and its downstream inflammatory mediator expressions. In conclusion, SFs are a potential nutraceutical to prevent high-energy density diet-induced cognitive impairments, which could be possibly explained by their mediating effects on insulin signaling and inflammatory responses in the brain.Variations in volatile organic compound (VOC) type and content can result in noticeable differences in fruit aroma. The genus Vaccinium encompasses over 500 distinct species of berry-producing plants, several of which are important to commercial horticulture. Understanding which VOCs are produced by different members of this genus could greatly aid efforts to improve the aroma of multiple Vaccinium crops by breeding for desirable fruit volatiles. This review summarizes the published research available on this topic, examining prior work done to characterize the volatile profiles of blueberries, cranberries, bilberries, lingonberries, whortleberries, and other Vaccinium berries. In addition, analytical methodologies used to obtain Vaccinium berry volatile profiles are discussed. Possible future directions for Vaccinium berry volatile research are also examined.