75%, obviously higher than that in pure CO2.Nisin is commonly used as a biopreservative in foods. For industrial production, nisin-producing Lactococcus lactis strains are usually grown to high cell densities to achieve the highest possible nisin titer. However, accumulation of lactic acid eventually halts production, even in pH-controlled fermentations. Here, we describe a nisin-producing L. lactis strain Ge001, which was obtained after transferring the nisin gene cluster from L. lactis ATCC 11454, by conjugation, into the natural mutant L. https://www.selleckchem.com/GSK-3.html lactis RD1M5, with low lactate dehydrogenase activity. The ability of Ge001 to produce nisin was tested using dairy waste as the fermentation substrate. To accommodate redox cofactor regeneration, respiration conditions were used, and to alleviate oxidative stress and to reduce adsorption of nisin onto the producing cells, we found it to be beneficial to add 1 mM Mn2+ and 100 mM Ca2+, respectively. A high titer of 12 084 IU/mL nisin could be reached, which is comparable to the highest titers reported using expensive, rich media. Summing up, we here present a 100% natural, robust, and sustainable approach for producing food-grade nisin and acetoin from readily available dairy waste.Although substituted benzimidazoles are common substructures in bioactive small molecules, synthetic methods for their derivatization are still limited. Previously, several enantioselective allylation reactions of benzimidazoles were reported that functionalize the nucleophilic nitrogen atom. Herein we describe a reversal of this inherent selectivity toward N-allylation by using electrophilic N-OPiv benzimidazoles with readily available 1,3-dienes as nucleophile precursors. This CuH-catalyzed approach utilizes mild reaction conditions, exhibits broad functional-group compatibility, and exclusively forms the C2-allylated product with excellent stereoselectivity.Small amyloid-β (Aβ) oligomers are believed to be key pathogenic species in Alzheimer's disease (AD). One suggested toxicity mechanism is the detergent model where oligomers remove lipid molecules from the bilayer. Senile plaques of AD patients also accumulate a 11 ratio of cholesterol/Aβ. What are the dominant structures of small Aβ42 oligomers with cholesterol molecules in aqueous solution? Here, we answer this question by performing atomistic replica exchange molecular dynamics simulations of Aβ42 dimers and trimers. Our simulations demonstrate that the interactions with cholesterol molecules change completely the energy landscape of small Aβ42 oligomers. This result shows that simulations in the bulk solution cannot recapitulate aggregation in the brain extracellular space.In coordination-based supramolecular materials such as metallogels, simultaneous temporal and spatial control of their assembly remains challenging. Here, we demonstrate that the combination of light with acids as stimuli allows for the spatiotemporal control over the architectures, mechanical properties, and shape of porous soft materials based on metal-organic polyhedra (MOPs). First, we show that the formation of a colloidal gel network from a preformed kinetically trapped MOP solution can be triggered upon addition of trifluoroacetic acid (TFA) and that acid concentration determines the reaction kinetics. As determined by time-resolved dynamic light scattering, UV-vis absorption, and 1H NMR spectroscopies and rheology measurements, the consequences of the increase in acid concentration are (i) an increase in the cross-linking between MOPs; (ii) a growth in the size of the colloidal particles forming the gel network; (iii) an increase in the density of the colloidal network; and (iv) a decrease in the ductility and stiffness of the resulting gel. We then demonstrate that irradiation of a dispersed photoacid generator, pyranine, allows the spatiotemporal control of the gel formation by locally triggering the self-assembly process. Using this methodology, we show that the gel can be patterned into a desired shape. Such precise positioning of the assembled structures, combined with the stable and permanent porosity of MOPs, could allow their integration into devices for applications such as sensing, separation, catalysis, or drug release.An antifungal metabolite, designated amphiol (1), was isolated from the culture broth of the fungus Pseudogymnoascus sp. PF1464. It exists as a mixture of inseparable tautomers, an acetal form and a keto form. The chemical structure was determined by spectroscopic analyses and chemical derivatization. Amphiol (1) showed antifungal but not antibacterial activities, while yeast mutant cells lacking ergosterol biosynthetic genes were less sensitive, implying a fungal specific, membrane-related mechanism of action.The coiled-coil domains of the putative yeast cargo receptors Emp46p and Emp47p (Emp46pcc and Emp47pcc) assemble into heterocomplexes at neutral pH. Upon lowering the pH, the complex dissociates and reassembles into homo-oligomers. A glutamate residue (E303) located on the hydrophobic surface of Emp46pcc serves as the pH-sensing switch for assembly and segregation, and we have suggested that its side chains are protonated in the heterocomplex, even at neutral pH. To examine this hypothesis, we constructed two structural models in which the side chains of E303 were negatively charged or protonated and analyzed the effects of these charged states on the structure of the heterocomplex using molecular dynamics (MD) simulations. The calculated structures suggested the side chains of E303 to be protonated in the heterocomplex, even at neutral pH. Based on these computational results, the pH dependence of Emp47pcc homo-oligomer assembly was experimentally modified by a glutamate mutation on its hydrophobic surface. The Q306E mutant of Emp47pcc underwent a structural transition at physiological pH. Our results suggest a method for modifying pH-dependent protein-protein interactions.Enantioselective bond formation between sterically hindered fragments to furnish acyclic products with vicinal quaternary centers is a formidable challenge. We report a solution that involves cocatalysis between a chiral Ir-(phosphoramidite,olefin) complex and La(OTf)3. This robust catalytic system effects highly enantioconvergent and regioselective alkylation of racemic tertiary α-allenyl alcohols with tetrasubstituted silyl ketene acetals. The transformation displays broad functional group tolerance for both reaction components and allows efficient generation of β-allenyl ester products in good yield and with excellent enantioselectivity. Furthermore, both the allene and ester functionalities were leveraged to upgrade the structural complexity of the products via a series of stereoselective metal-catalyzed functionalization reactions.