Synthesis and Assay of Vibrio Quorum Sensing Inhibitors.

Bacteria detect local population numbers using quorum sensing, a method of cell-cell communication broadly utilized to control bacterial behaviors. In Vibrio species, the master quorum sensing regulators LuxR/HapR control hundreds of quorum sensing genes, many of which influence virulence, metabolism, motility, and more. Thiophenesulfonamides are potent inhibitors of LuxR/HapR that bind the ligand pocket in these transcription factors and block downstream quorum sensing gene expression. This class of compounds served as the basis for the development of a set of simple, robust, and educational procedures for college students to assimilate their chemistry and biology skills using a CURE model: course-based undergraduate research experience. Optimized protocols are described that comprise three learning stages in an iterative and multi-disciplinary platform to engage students in a year-long CURE: (1) design and synthesize new small molecule inhibitors based on the thiophenesulfonamide core, (2) use structural modeling to predict binding affinity to the target, and (3) assay the compounds for efficacy in microbiological assays against specific Vibrio LuxR/HapR proteins. The described reporter assay performed in E. coli successfully predicts the efficacy of the compounds against target proteins in the native Vibrio species.

Comparing reactivation and retreatment for three doses of bevacizumab in type 1 retinopathy of prematurity.

PURPOSE: To determine timing and rates of reactivation and retreatment of type 1 retinopathy of prematurity (ROP) after treatment with either 0.125 mg, 0.250 mg, or 0.500 mg of intravitreal bevacizumab (IVB). METHODS: Retrospective data, including demographic information, past medical history, and ROP characteristics were analyzed for babies with type 1 ROP treated with IVB at Riley Hospital for Children for the perioed 2014-2021. RESULTS: A total of 84 patients met inclusion criteria: 29 patients received 0.125 mg of IVB; 39, 0.250 mg; and 16, 0.500 mg. Of the 84, 67 (80%) had additional laser treatment because of late reactivation (n = 52) or persistent avascular retina (PAR) (n = 15). Subsequent laser treatment was more common with lower doses: 0.125 mg (n = 27 [93%]); 0.250 mg (n = 31 [80%]); 0.500 mg (n = 9 [57%]) (P = 0.012). There was no difference between groups with regard to reason for subsequent laser treatment (reactivation vs PAR). The 0.125 mg group required retreatment because of reactivation 3.8 weeks sooner than the other dosing groups (P = 0.047). CONCLUSIONS: The outcomes comparing three doses of IVB for severe ROP showed a difference in the timing of secondary treatment, with the lower dosing group requiring laser for reactivation earlier.

Amino acid divergence in the ligand-binding pocket of Vibrio LuxR/HapR proteins determines the efficacy of thiophenesulfonamide inhibitors.

The quorum-sensing signaling systems in Vibrio bacteria converge to control levels of the master transcription factors LuxR/HapR, a family of highly conserved proteins that regulate gene expression for bacterial behaviors. A compound library screen identified 2-thiophenesulfonamide compounds that specifically inhibit Vibrio campbellii LuxR but do not affect cell growth. We synthesized a panel of 50 thiophenesulfonamide compounds to examine the structure-activity relationship effects on Vibrio quorum sensing. The most potent molecule identified, PTSP (3-phenyl-1-(thiophen-2-ylsulfonyl)-1H-pyrazole), inhibits quorum sensing in multiple strains of V. vulnificus, V. parahaemolyticus, and V. campbellii at nanomolar concentrations. However, thiophenesulfonamide inhibition efficacy varies significantly among Vibrio species: PTSP is most inhibitory against V. vulnificus SmcR, but V. cholerae HapR is completely resistant to all thiophenesulfonamides tested. Reverse genetics experiments show that PTSP efficacy is dictated by amino acid sequence in the putative ligand-binding pocket: F75Y and C170F SmcR substitutions are each sufficient to eliminate PTSP inhibition. Further, in silico modeling distinguished the most potent thiophenesulfonamides from less-effective derivatives. Our results revealed the previously unknown differences in LuxR/HapR proteins that control quorum sensing in Vibrio species and underscore the potential for developing thiophenesulfonamides as specific quorum sensing-directed treatments for Vibrio infections.

Advent of Big Data technology in environment and water management sector.

Big Data is on the verge of explosion in terms of popularity in recent decades, and such a trend is not going to stop anytime soon as it has a lot of room to grow. The increased integration of IoT devices, faster access to the Internet, and advances in the computational power of mainstream devices have drastically increased the feasibility for the same while making it more practical to implement gradually. The reach and applicability of Big Data are diversified, yet widespread, and one of its key implementations falls under the environment arena. In an attempt to provide novel Big Data allied solutions in one or more aspects of water management sector, a substantial amount of research work has been carried out in recent years. This paper discusses how Big Data influences the abovementioned arenas and the extent of importance that it has. Several aspects of this field are uprooted, are discussed, and have seen real-world applicability. Various presently deployed applications, in the sub-fields of environment and water management are studied, and given an inclusive review. Finally, the current challenges and limitations pertaining to Big Data are discussed and proper (in theory) solutions are proposed which seem to have promising results. The future scope of Big Data is also considered with its viability taken into consideration. Several assessments and opinions are then cited.

Addition-substitution reactions of 2-thio-3-chloroacrylamides with carbon, nitrogen, oxygen, sulfur and selenium nucleophiles.

Synthetically versatile conjugate addition of a range of carbon, nitrogen, oxygen, sulfur and selenium nucleophiles to the highly functionalised 2-thio-3-chloroacrylamides is described. The stereochemical and synthetic features of this transformation are discussed in detail. In most instances, the nucleophile replaces the chloro substituent with retention of stereochemistry. With the oxygen nucleophiles, a second addition can occur leading to acetals, while with the nitrogen nucleophiles, E-Z isomerism occurs in the resulting enamine derivatives. The ratio of the E/Z isomers can be rationalised on the basis of the substituent and the level of oxidation.

The influence of reaction conditions on the Diels-Alder cycloadditions of 2-thio-3-chloroacrylamides; investigation of thermal, catalytic and microwave conditions.

The Diels-Alder cycloadditions of cyclopentadiene and 2,3-dimethyl-1,3-butadiene to a range of 2-thio-3-chloroacrylamides under thermal, catalytic and microwave conditions is described. The influence of reaction conditions on the outcome of the cycloadditions, in particular the stereoselectivity and reaction efficiency, is discussed. While the cycloadditions have been attempted at the sulfide, sulfoxide and sulfone levels of oxidation, use of the sulfoxide derivatives is clearly beneficial for stereoselective construction of Diels-Alder cycloadducts.

Investigation of the synthetic and mechanistic aspects of the highly stereoselective transformation of alpha-thioamides to alpha-thio-beta-chloroacrylamides.

Treatment of a series of alpha-thioamides with N-chlorosuccinimide results in efficient transformation to the analogous alpha-thio-beta-chloroacrylamides. The mechanistic pathway has been established through isolation and characterisation of intermediate compounds. The scope of the transformation has been explored-aryl and alkylthio substituents, primary, secondary and tertiary amides can be employed. In most instances, the chloroacrylamides are formed exclusively as the Z-stereoisomer; however, with tertiary propanamides or with amides derived from butanoic or pentanoic acid a mixture of E- and Z-stereoisomers is formed.

Synthesis, isolation and characterisation of beta-sitosterol and beta-sitosterol oxide derivatives.

Beta-sitosterol is the most prevalent plant cholesterol derivative (phytosterol) and can undergo similar oxidation to cholesterol, leading to beta-sitosterol oxides. The biological impact of phytosterol oxides has only been evaluated in a phytosterol blend (usually of beta-sitosterol, campesterol, stigmasterol and dihydrobrassicasterol). The lack of pure phytosterols, including beta-sitosterol, hinders the collection of significant toxicity data on the individual beta-sitosterol oxides. An efficient synthetic route to multi-gram quantities of pure beta-sitosterol is described here, together with the first syntheses and characterisation of pure beta-sitosterol oxides.

Qualitative and quantitative comparison of the cytotoxic and apoptotic potential of phytosterol oxidation products with their corresponding cholesterol oxidation products.

Phytosterols contain an unsaturated ring structure and therefore are susceptible to oxidation under certain conditions. Whilst the cytotoxicity of the analogous cholesterol oxidation products (COP) has been well documented, the biological effects of phytosterol oxidation products (POP) have not yet been fully ascertained. The objective of the present study was to examine the cytotoxicity of beta-sitosterol oxides and their corresponding COP in a human monocytic cell line (U937), a colonic adenocarcinoma cell line (CaCo-2) and a hepatoma liver cell line (HepG2). 7beta-Hydroxysitosterol, 7-ketositosterol, sitosterol-3beta,5alpha,6beta-triol and a sitosterol-5alpha,6alpha-epoxide-sitosterol-5beta,6beta-epoxide (6:1) mixture were found to be cytotoxic to all three cell lines employed; the mode of cell death was by apoptosis in the U937 cell line and necrosis in the CaCo-2 and HepG2 cells. 7beta-Hydroxysitosterol was the only beta-sitosterol oxide to cause depletion in glutathione, indicating that POP-induced apoptosis may not be dependent on the generation of an oxidative stress. A further objective of this study was to assess the ability of the antioxidants alpha-tocopherol, gamma-tocopherol and beta-carotene to modulate POP-induced cytotoxicity in U937 cells. Whilst alpha/gamma-tocopherol protected against 7beta-hydroxycholesterol-induced apoptosis, they did not confer protection against 7beta-hydroxysitosterol- or 7-ketositosterol-induced toxicity, indicating that perhaps COP provoke different apoptotic pathways than POP. beta-Carotene did not protect against COP- or POP-induced toxicity. In general, results indicate that POP have qualitatively similar toxic effects to COP. However, higher concentrations of POP are required to elicit comparable levels of toxicity.