Search Results (6)

Background/Objectives: Cholesterol is an essential lipid required for membrane structure and normal physiological functions. However, dysregulation of cholesterol homeostasis, manifesting as hypercholesterolemia, can precipitate a range of metabolic and cardiovascular diseases. Blautia species are important gut commensals, but their role in cholesterol metabolism remains poorly defined. Methods: A total of 63 Blautia strains isolated from human fecal samples were screened for cholesterol conversion using the o-phthalaldehyde colorimetric assay in cholesterol-containing media with or without oxgall. Cholesterol removal by live and heat-inactivated cells was compared. Metabolomic, transcriptomic, and proteomic analyses were employed to investigate molecular mechanisms and involved genes. Results: Nine strains significantly lowered cholesterol levels (live cells: 31–78%; heat-inactivated cells: 8–64%), with the B. hominis strain HA2291, the Blautia sp. strain HA3515, and the B. coccoides strain HA4419 showing the strongest activity. Oxgall increased cholesterol removal by live cells to 74–83%, indicating bile-tolerant metabolism activity. Metabolomic profiling revealed that B. hominis HA2291 transformed cholesterol into cholest-4-en-3-one and epicholestanol. An SCP2-like protein, RS03310, was identified as a candidate cholesterol-interacting factor; its recombinant form catalyzed measurable NAD⁺-dependent cholesterol oxidation in vitro. Conclusions: Blautia hominis HA2291 may employ multiple in vitro strategies for cholesterol-lowering, including cell-surface adsorption (heat-inactivated cells), bile-enhanced removal (oxgall effect), and enzymatic transformation, with the gene RS03310 implicated as the main contributor. These findings provide in vitro mechanistic insights into Blautia-mediated cholesterol metabolism, highlight RS03310 as a candidate gene associated with cholesterol biotransformation, and advance our understanding of the potential role of Blautia in host cholesterol homeostasis. Full article

The sustainable treatment of uranium-containing wastewater is of significant importance for environmental protection. This study reports a novel Polyethyleneimine-4-cyanobenzaldehyde/p-Phthalaldehyde-Amidoxime (PEI-PAC-AO) adsorbent for the effective extraction of uranium from aqueous solutions. The structural and performance characteristics of the adsorbents were analyzed through FT-IR, TGA, SEM, CA, and ICP-MS. Adsorption mechanisms were investigated using X-ray photoelectron spectroscopy (XPS), revealing that uranium adsorption is due to coordination with N and O atoms in the amidoxime groups. Batch adsorption experiments showed that PEI-PAC-AO exhibited excellent removal efficiency at pH 6. The static adsorption performance better fits the Langmuir model and pseudo-second-order kinetics. Adsorption results indicated that the removal extent of uranium ions remained at 80% after nine consecutive adsorption cycles using 0.5 M nitric acid as the eluent. These findings suggest that PEI-PAC-AO is a sustainable and promising material for the efficient removal of uranium from wastewater, offering a sustainable and environmentally friendly approach that contributes to environmentally responsible wastewater treatment strategies. Full article

A facile and sensible spectrofluorimetric approach for the measurement of two antipsychotic medications, aripiperazole (ARP) and clozapine (CLZ), was devised and validated. The approach involves reacting the examined medicines with o-phthalaldehyde in the presence of β-mercaptoethanol in a borate buffer of pH 9.0 and pH 10 for ARP and CLZ, respectively, to produce a robustly fluorescent compound that is detected at 450 nm following excitation at 340 nm. The experimental variables influencing the performance and product stability were thoroughly investigated and optimized. Under optimal conditions, the intensity of the fluorescence was linear during a concentration range of 0.1–0.5 μg/mL, with a limit of detection (0.0391 and 0.0400 μg/mL) and limit of quantitation (0.1035 and 0.1332 μg/mL), respectively, for ARP and CLZ. The suggested approach was successful in analyzing commercialized tablets. A statistical investigation of the results produced by the suggested and standard methods showed no remarkable variation in the precision and accuracy of the two approaches. A chemical mechanism using o-phthalaldehyde was proposed. Full article

SMTP (the name SMTP is derived from Stachybotrys microspora triprenyl phenol) is a family of triprenyl phenol secondary metabolites from a black mold, Stachybotrys microspora. Some SMTP congeners exhibit anti-inflammatory and profibrinolytic activities that, in combination, contribute to the treatment of ischemic stroke. The final step in the SMTP biosynthesis is a non-enzymatic amine conjugation with an o-phthalaldehyde moiety of the precursor pre-SMTP, which can form adducts with proteins and nucleic acids. Thus, pre-SMTP formation should be a precisely regulated, rate-limiting step in the SMTP biosynthesis. To address the mechanism backing this regulation, we purified a metabolite that rapidly disappeared following amine feeding, identifying a novel compound, pri-SMTP. Furthermore, an enzyme, designated as pri-SMTP oxidase, responsible for pri-SMTP conversion to pre-SMTP, was purified. The formation of pri-SMTP, which is regulated by nitrogen and carbon nutrients, occurred in particular septate mycelia. Although pri-SMTP oxidase was expressed constitutively, the consumption of pri-SMTP was accelerated only when a primary amine was fed. Thus, SMTP biosynthesis is regulated by at least three mechanisms: (i) pri-SMTP formation affected by nutrients, (ii) the compartmentalization of pri-SMTP formation/storage, and (iii) amine-regulated pri-SMTP oxidation. Amine-regulated SMTP formation (i.e., amine-capturing with pre-SMTP) may play a role in the nitrogen acquisition/assimilation strategy in S. microspora, since pri-SMTP synthesis occurs on non-preferred nitrogen. Full article

Herein, we report a new automated flow method based on zone fluidics for the simultaneous determination of homocysteine and homocysteine thiolactone using fluorimetric detection (λ_ext = 370 nm/λ_em = 480 nm). Homocysteine thiolactone is hydrolyzed on-line in alkaline medium (1 mol L⁻¹ NaOH) to yield homocysteine, followed by reaction with o-phthalaldehyde in a single step. Derivatization is rapid without the need of elevated temperatures and stopped-flow steps, while specificity is achieved through a unique reaction mechanism in the absence of nucleophilic compounds. Mixtures of the analytes can be analyzed quantitatively after specific separation with fluorosurfactant-capped gold nanoparticles that are selectively aggregated by homocysteine, leaving the thiolactone analogue in solution. As low as 100 nmol L⁻¹ of the analyte(s) can be quantified in aqueous solutions, while concentrations > 2 μmol L⁻¹ can be analyzed in artificial and real urine matrix following 20-fold dilution. The percent recoveries ranged between 87 and 119%. Full article

In the present study, we report the results of our investigation of the oxidative forced degradation of glutathione in its nutraceutical formulations by two validated analytical methods. The first is based on the reaction of glutathione with o-phthalaldehyde through an automated zone fluidics flow platform and fluorimetric detection (λ_ex/λ_em = 340/425 nm). The second is based on the separation of glutathione and its oxidation product by a green reversed-phase HPLC method coupled to direct UV detection, at 210 nm. A solution of 3% w/v H₂O₂ provided fast oxidation of more than 95% of glutathione to yield oxidized glutathione in a time period of 180 min. The mechanism of the oxidation was proved to follow pseudo-first order kinetics. The k, t₉₀ and t_1/2 values were calculated. Full article