Activity of Debaryomyces hansenii UFV-1 α-galactosidases against α-d-galactopyranoside derivatives

Novel Galactopyranoside Esters: Synthesis, Mechanism, In Vitro Antimicrobial Evaluation and Molecular Docking Studies

One-step direct unimolar valeroylation of methyl α-D-galactopyranoside (MDG) mainly furnished the corresponding 6-O-valeroate. However, DMAP catalyzed a similar reaction that produced 2,6-di-O-valeroate and 6-O-valeroate, with the reactivity sequence as 6-OH > 2-OH > 3-OH,4-OH. To obtain novel antimicrobial agents, 6-O- and 2,6-di-O-valeroate were converted into several 2,3,4-tri-O- and 3,4-di-O-acyl esters, respectively, with other acylating agents in good yields. The PASS activity spectra along with in vitro antimicrobial evaluation clearly indicated that these MDG esters had better antifungal activities than antibacterial agents. To rationalize higher antifungal potentiality, molecular docking was conducted with sterol 14α-demethylase (PDB ID: 4UYL, Aspergillus fumigatus), which clearly supported the in vitro antifungal results. In particular, MDG ester 7−12 showed higher binding energy than the antifungal drug, fluconazole. Additionally, these compounds were found to have more promising binding energy with the SARS-CoV-2 main protease (6LU7) than tetracycline, fluconazole, and native inhibitor N3. Detailed investigation of Ki values, absorption, distribution, metabolism, excretion, and toxicity (ADMET), and the drug-likeness profile indicated that most of these compounds satisfy the drug-likeness evaluation, bioavailability, and safety tests, and hence, these synthetic novel MDG esters could be new antifungal and antiviral drugs.

Probiotic and nutritional effects of Debaryomyces hansenii on animals

Debaryomyces hansenii comes of age as a new potential probiotic for terrestrial and aquatic animals. Probiotic properties, including inmunostimulatory effects, gut microbiota modulation, enhanced cell proliferation and differentiation, and digestive function improvements have been related to the oral delivery of D. hansenii. Its functional compounds, such as cell wall components and polyamines, have been identified and implicated in its immunomodulatory activity. In addition, in vitro studies using immune cells have shown standpoints on the possible recognition, regulation, and effector immune mechanisms stimulated by this yeast. This review describes historic, cutting-edge research findings, implications, and perspectives on the use of D. hansenii as a promising probiotic for animals. KEY POINTS: • Debaryomyces hansenii has probiotic effects in terrestrial and aquatic animals. • Nutritional effects could be associated to probiotic D. hansenii strains. • β-D-Glucan and polyamines from D. hansenii are associated to probiotic properties. • Adoption by the industry is expected in the next years.

Microbial modulation of host body composition and plasma metabolic profile

The gut microbiota is a critical mediator of nutrition and disease risk. Like most complex traits, the microbiome is under genetic regulation and differs between inbred strains of mice. We tested the effect of fecal microbiota transplantation (FMT) on obesity, and plasma glucose. For this study, we collected microbiota from 2 inbred strains of mice which differ in adiposity and glucose tolerance, C57BL/6J and WSB/EiJ. C57BL/6J female mice (n = 18) were first treated with antibiotics for 4 weeks to ablate the microbiota. Following ablation, the mice were transplanted with microbiota from a C57BL/6J or a WSB/EiJ mouse and clinical traits and plasma metabolomic profiles were interrogated at 2- and 4-weeks post-transplantation. Unexpectedly, the mice receiving WSB/EiJ microbiota increased adiposity but decreased plasma glucose. Metabolomic and 16S microbiota profiling indicated broad metabolic changes occurred during and after FMT. Detailed analysis of these interactions demonstrated specific microbiota-host metabolite interactions which may alter disease susceptibility.

Crystal structure of 4-nitro-phenyl 6-O-ethyl-β-d-galacto-pyran-oside monohydrate

The synthesis and crystal structure of the title compound, C14H19NO8·H2O, prepared in three steps from 6-O-ethyl-1,2;3,4-di-O-iso-propyl-idene-α-d-galacto-pyran-ose using protecting-group strategies employed in carbohydrate chemistry, is reported. The asymmetric unit consists of a single galactoside mol-ecule, in which the pyran-oid ring has a 4C1 conformation and the 4-nitro-phenyl moiety is essentially planar. In the crystal, each carbohydrate is surrounded by other d-galactose residues and water mol-ecules, linked by O-H⋯O hydrogen bonds involving all hy-droxy groups, giving a two-dimensional substructure lying parallel to (100) and extended into three dimensions by C-H⋯O inter-actions.

Solution and Solid-Phase Stereocontrolled Synthesis of 1,2-cis-Glycopyranosides with Minimally Protected Glycopyranosyl Donors Catalyzed by BF3-N,N-Dimethylformamide Complex

Methods are described for the stereoselective synthesis of 1,2-cis glycopyranosides in the d-galacto, d-gluco, and 2-azido-2-deoxy-d-glucopyranoside series utilizing minimally protected (3-bromo-2-pyridyloxy) β-d-glycopyranosyl donors in the presence of BF3-N,N-dimethylformamide (DMF) as a catalyst and a variety of alcohol acceptors relying on the "remote activation concept". Precursors to antifreeze glycopeptide components are synthesized in excellent yields and high α/β ratios. The method is adaptable to one-pot sequential glycosidation as well as to solid-supported synthesis giving access to diverse sets of minimally protected α-d-glycopyranosides as major products.