Long-Term Stability and Efficacy of NCT Solutions.

To realize the potential for the use of -chlorotaurine (NCT) in healthcare, a better understanding of the long-term stability of the compound in water is needed. An array of analytical procedures is required that can measure changes in NCT concentration over time and allow for the detection and identification of contaminants and likely degradation end products. We used UV-Vis and NMR spectroscopy, HPLC, and LCMS to establish the stability of NCT in solutions subjected to prolonged ambient and elevated temperatures.

Modification of Superabsorbent Polymer Granules and Fibers for Antimicrobial Efficacy and Malodor Control.

Superabsorbent polymer (SAP) granules, typically used in personal care devices such as diapers, incontinence devices, hygiene pads, and wound dressings, and granular particles of zeolite and bentonite were each subjected to modification by exposure to solutions of 1-chloro-2,2,5,5-tetramethyl-4-imidazolidinone (MC) in ethanol at room temperature. The air-dried granules showed newly acquired properties attributable to the presence of active chlorine (Cl). The treated particles effectively oxidized the malodorant 3-mercapto-3-methylbutanol (3M3MB).

A Synthetic Polymicrobial Community Biofilm Model Demonstrates Spatial Partitioning, Tolerance to Antimicrobial Treatment, Reduced Metabolism, and Small Colony Variants Typical of Chronic Wound Biofilms.

Understanding chronic wound infection is key for successful treatment and requires accurate laboratory models. We describe a modified biofilm flow device that effectively mimics the chronic wound environment, including simulated wound fluid, a collagen-based 3D biofilm matrix, and a five-species mixture of clinically relevant bacteria (, , , , and ). Mixed biofilms were cultured for between 3 and 14 days with consistent numbers of bacteria that exhibited reduced metabolic activity, which increased with a high dose of glucose.

Hypochlorous acid as a disinfectant for high-risk HPV: Insight into the mechanism of action.

Medical instruments that are not autoclavable but may become contaminated with high-risk human papillomaviruses (HPVs) during use must be thoroughly disinfected to avoid the possibility of iatrogenic transmission of infection. There is an expectation that prolonged soaking of instruments in the United States Food and Drug Administration-cleared chemical disinfectant solutions will result in high-level decontamination, but HPV16 and HPV18 are known to be resistant to commonly used formulations. However, they are susceptible to a variety of oxidative agents, including those based on chlorine.

Modifications of IL-6 by Hypochlorous Acids: Effects on Receptor Binding.

Interleukin-6 (IL-6) has been implicated in the pathogenesis of inflammatory events including those seen with COVID-19 patients. Positive clinical responses to monoclonal antibodies directed against IL-6 receptors (IL-6Rs) suggest that interference with IL-6-dependent activation of pro-inflammatory pathways offers a useful approach to therapy. We exposed IL-6 to hypochlorous acid (HOCl) at concentrations reported to develop .

Testing the efficacy of topical antimicrobial treatments using a two- and five-species chronic wound biofilm model.

Aims: The effectiveness of commercially available wound dressings and a HOCl gel formulation was tested against two- and five-species biofilms in a dynamic in vitro chronic wound infection model.

Method: Two-species biofilms (Pseudomonas aeruginosa and Staphylococcus aureus) were cultured using a biofilm flow device and treated with wound dressings containing silver, iodine, polyhexamethylene biguanide, crystal violet or HOCl gel at 5 h. Five-species biofilms (P.

Control of felinine-derived malodor in cat litter.

Objectives: Malodors stemming from soiled cat litter are a major frustration for cat owners, despite the widespread use of absorbent litters with claims of odor control. Technologies for effective litter odor control have not been rigorously evaluated. Here, we report on the effectiveness of a novel litter formulation of 1-monochlorodimethylhydantoin (MCDMH)-modified clinoptilolite zeolite (MCDMH-Z) to control the odors of 3-mercapto-3-methylbutanol (3M3MB) and ammonia, the principal products generated by the enzymatic breakdown of felinine and urea, respectively.

Modification of Major Contributors Responsible for Latrine Malodor on Exposure to Hypochlorous Acid: The Potential for Simultaneously Impacting Odor and Infection Hazards to Encourage Latrine Use.

Open defecation remains a common practice in developing countries and leads to high incidence and prevalence of acute gastroenteritis, which is most often caused by human noroviruses (human NoV). Encouraging the use of toilets and pit latrines is one method of improving sanitation; however, it is often hindered by not only cultural traditions but also from a reluctance to use latrines and toilets due to their odor and impression of uncleanliness. In an effort to establish new means to encourage toilet and latrine use, laboratory experiments tested the ability of hypochlorous acid (HOCl) to modify the malodorous compounds identified in the air in latrines in developing countries (indole, p-cresol, dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS), and butyric acid) and inactivate MS2 bacteriophage, a surrogate for human NoV.

Indirect DNA Sequence Recognition and Its Impact on Nuclease Cleavage Activity.

LAGLIDADG meganucleases are DNA cleaving enzymes used for genome engineering. While their cleavage specificity can be altered using several protein engineering and selection strategies, their overall targetability is limited by highly specific indirect recognition of the central four base pairs within their recognition sites. In order to examine the physical basis of indirect sequence recognition and to expand the number of such nucleases available for genome engineering, we have determined the target sites, DNA-bound structures, and central four cleavage fidelities of nine related enzymes.

An investigation into the butyrylcholinesterase-catalyzed hydrolysis of formylthiocholine using heavy atom kinetic isotope effects.

Heavy atom kinetic isotope effects (KIEs) were determined for the butyrylcholinesterase-catalyzed hydrolysis of formylthiocholine (FTC). The leaving-S, carbonyl-C, and carbonyl-O KIEs are (34)k=0.994±0.

A mechanistic study of thioester hydrolysis with heavy atom kinetic isotope effects.

The carbonyl-C, carbonyl-O, and leaving-S kinetic isotope effects (KIEs) were determined for the hydrolysis of formylthiocholine. Under acidic conditions, (13)k(obs) = 1.0312, (18)k(obs) = 0.

Mechanistic investigations of the hydrolysis of amides, oxoesters and thioesters via kinetic isotope effects and positional isotope exchange.

The hydrolysis of amides, oxoesters and thioesters is an important reaction in both organic chemistry and biochemistry. Kinetic isotope effects (KIEs) are one of the most important physical organic methods for determining the most likely transition state structure and rate-determining step of these reaction mechanisms. This method induces a very small change in reaction rates, which, in turn, results in a minimum disturbance of the natural mechanism.

A kinetic isotope effect and isotope exchange study of the nonenzymatic and the equine serum butyrylcholinesterase-catalyzed thioester hydrolysis.

Formylthiocholine (FTC) was synthesized and found to be a substrate for nonenzymatic and butyrylcholinesterase (BChE)-catalyzed hydrolysis. Solvent (D2O) and secondary formyl-H kinetic isotope effects (KIEs) were measured by an NMR spectroscopic method. The solvent (D2O) KIEs are (D2O)k = 0.

A kinetic and isotope effect investigation of the urease-catalyzed hydrolysis of hydroxyurea.

The urease-catalyzed hydrolysis of hydroxyurea is known to exhibit biphasic kinetics, showing a rapid burst phase followed by a slow plateau phase. Kinetic isotope effects for both phases of this reaction were measured at pH 6.0 and 25 °C.

3-(Arylthiomethyl)isoxazole-4,5-dicarboxamides: chemoselective nucleophilic chemistry and insecticidal activity.

A collection of 91 3-(arylthiomethyl)isoxazole-4,5-dicarboxamides was prepared starting from dimethyl 3-(chloromethyl)isoxazole-4,5-dicarboxylate. The thioether moieties in these compounds were subsequently oxidized to give the corresponding 3-(arylsulfonylmethyl)isoxazole-4,5-dicarboxamides. By carefully controlling stoichiometry and reaction conditions, the C4 and C5 carbomethoxy groups could be differentially derivatized to carboxamides.

Structural basis for the sugar nucleotide and acyl-chain selectivity of Leptospira interrogans LpxA.

The first step of lipid A biosynthesis is catalyzed by LpxA in Escherichia coli (EcLpxA), an acyltransferase selective for UDP-GlcNAc and R-3-hydroxymyristoyl-acyl carrier protein (ACP). Leptospira interrogans LpxA (LiLpxA) is extremely selective for R-3-hydroxylauroyl-ACP and an analogue of UDP-GlcNAc, designated UDP-GlcNAc3N, in which NH(2) replaces the GlcNAc 3-OH group. EcLpxA does not discriminate between UDP-GlcNAc and UDP-GlcNAc3N; however, E.

Uridine-based inhibitors as new leads for antibiotics targeting Escherichia coli LpxC.

The UDP-3-O-(R-3-hydroxyacyl)-N-acetylglucosamine deacetylase LpxC catalyzes the committed reaction of lipid A (endotoxin) biosynthesis in Gram-negative bacteria and is a validated antibiotic target. Although several previously described compounds bind to the unique acyl chain binding passage of LpxC with high affinity, strategies to target the enzyme's UDP-binding site have not been reported. Here the identification of a series of uridine-based LpxC inhibitors is presented.

4'-Methyl-4,5'-bithiazole-based correctors of defective delta F508-CFTR cellular processing.

The synthesis and Delta F508-CFTR corrector activity of a 148-member methylbithiazole-based library are reported. Synthetic routes were devised and optimized to generate methylbithiazole analogs in four steps. Corrector potency and efficacy were assayed using epithelial cells expressing human Delta F508-CFTR.

A facile synthesis of new 5H-indazolo[3,2-b]benzo[d]-1,3-oxazines via one-pot intramolecular Bis-heterocyclizations.

The parent 5H-indazolo[3,2-b]benzo[d]-1,3-oxazine heterocycle as well as a series of novel analogues have been synthesized utilizing two subsequent intramolecular heterocyclizations in one pot. A variety of diversity groups were added to explore the scope of this reaction and to provide a number of new compounds for biological screening.

1,3,5-triazine-based mass spectral tagging of one-bead one-compound libraries.

A triazine-based mass encoding strategy that accommodates cleavable linker, isotopic labeling, and diversity receptor moieties is reported. The resulting triazine-based tags, which are coupled to bifunctionalized TentaGel resin in a one-pot transformation, enable the construction of a 1-oxa-2,8-diazaspiro[4.5]dec-2-ene-7-carboxamide library and facilitate decoding by equalizing the ionization potential of the liberated tags in single bead MALDI-TOF experiments as well as balancing the reactivity of the starting tags in the resin coupling step.

Selective nucleophilic chemistry in the synthesis of 5-carbamoyl-3-sulfanylmethylisoxazole-4-carboxylic acids.

The solution-phase syntheses of 5-carbamoyl-3-sulfanylmethylisoxazole-4-carboxylic acids were accomplished from dimethyl 3-chloromethylisoxazole-4,5-dicarboxylate by selective nucleophilic chemistry. For example, treatment of this trifunctionalized core with 3-bromobenzylamine and subsequent X-ray analysis identified the sole product as methyl 5-(3-bromobenzylcarbamoyl)-3-chloromethylisoxazole-4-carboxylate. Subjecting this amide/ester to thiophenol in the presence of 1 N NaOH completed the two-step transformation of this versatile starting material to the targeted 5-carbamoyl-3-sulfanylmethylisoxazole-4-carboxylic acid.

On-bead combinatorial techniques for the identification of selective aldose reductase inhibitors.

Aldose reductase (AKR1B1; ALR2; E.C. 1.

Diazocinones: synthesis and conformational analysis.

1,2,4,5-Tetrazines (prepared from aryl nitriles) condense with isoxazolylcyclobutanones (prepared from 3-benzenesulfonyl-3-vinylcyclobutanol) in methanolic KOH to give conformationally restricted 6-isoxazol-5-yl-6,7-dihydro-5H-[1,2]diazocin-4-ones. The solution 1H NMR spectra of dihydrodiazocinone 1a with phenyl moieties at C3 and C8 reveal two conformations of the eight-membered heterocycle that are non-interconverting on the NMR time scale at ambient temperature. The kinetics of the conversion process, followed by 1H NMR between 21 and 70 degrees C in DMSO solution, yield an activation energy of approximately 21 kcal/mol relative to the kinetic conformer and show an equilibrated ratio of approximately 5:1 of the thermodynamic to the kinetic conformers.

Phenylglycine and sulfonamide correctors of defective delta F508 and G551D cystic fibrosis transmembrane conductance regulator chloride-channel gating.

Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel cause cystic fibrosis. The delta F508 mutation produces defects in channel gating and cellular processing, whereas the G551D mutation produces primarily a gating defect. To identify correctors of gating, 50,000 diverse small molecules were screened at 2.