Antibacterial Activity of Pharmaceutical-Grade Rose Bengal: An Application of a Synthetic Dye in Antibacterial Therapies

Rose bengal has been used in the diagnosis of ophthalmic disorders and liver function, and has been studied for the treatment of solid tumor cancers. To date, the antibacterial activity of rose bengal has been sporadically reported; however, these data have been generated with a commercial grade of rose bengal, which contains major uncontrolled impurities generated by the manufacturing process (80–95% dye content). A high-purity form of rose bengal formulation (HP-RBf, >99.5% dye content) kills a battery of Gram-positive bacteria, including drug-resistant strains at low concentrations (0.01–3.13 μg/mL) under fluorescent, LED, and natural light in a few minutes. Significantly, HP-RBf effectively eradicates Gram-positive bacterial biofilms. The frequency that Gram-positive bacteria spontaneously developed resistance to HP-RB is extremely low (less than 1 × 10⁻¹³). Toxicity data obtained through our research programs indicate that HP-RB is feasible as an anti-infective drug for the treatment of skin and soft tissue infections (SSTIs) involving multidrug-resistant (MDR) microbial invasion of the skin, and for eradicating biofilms. This article summarizes the antibacterial activity of pharmaceutical-grade rose bengal, HP-RB, against Gram-positive bacteria, its cytotoxicity against skin cells under illumination conditions, and mechanistic insights into rose bengal’s bactericidal activity under dark conditions.     

A new concept for the preparation of beta-L- and beta-D-2',3'-dideoxynucleoside analogues

[reaction: see text] A new method for the synthesis of 2',3'-dideoxynucleoside analogues has been developed. An electrochemical activation of 2-substituted furans is followed by the coupling with a pyrimidine or purine base. This gives planar furyl nucleosides as key intermediates, which are hydrogenated cis-selectively to give the corresponding beta-2',3'-dideoxynucleosides as racemic mixtures. An enzymatic kinetic resolution gives rise to beta-D- and beta-L-configured derivatives in high optical purity. This is exemplified by the synthesis of beta-D- and beta-L-3'-deoxythymidine.     

Periodically poled lithium niobate monolithic nanosecond optical parametric oscillators and generators

We fabricated and characterized periodically poled lithium niobate monolithic optical parametric oscillators (OPO's) and generators. The compact monolithic devices were trivial to align and operate and provided widely tunable, nearly diffraction-limited, stable output pulses. Low thresholds and high conversion efficiencies were obtained when the devices were pumped with 3.5-ns 1.064-mum pulses. In addition, the monolithic OPO devices exhibited broad tuning by crystal rotation through noncollinear phase matching. The bandwidth-broadening effects exhibited in the noncollinear phase-matching geometry were measured and explained.     

A new class of indolosesquiterpene alkaloids from polyathia suaveolens

Three new alkaloids, polyavolensin, polyavolensinol and polyavolensinone, isolated from the stem of Polyathia suaveolens are shown to belong to a new class of indolosesquiterpenes with structures 4, 5, 6 respectively by PMR, CMR and mass spectrometry. They have also been interrelated by chemical reactions.     

Direct observation of azimuthal correlations between DNA in hydrated aggregates

This study revisits the classical x-ray diffraction patterns from hydrated, noncrystalline fibers originally used to establish the helical structure of DNA. We argue that changes in these diffraction patterns with DNA packing density reveal strong azimuthally dependent interactions between adjacent molecules up to approximately 40 A interaxial or approximately 20 A surface-to-surface separations. These interactions appear to force significant torsional "straightening" of DNA and strong azimuthal alignment of nearest neighbor molecules. The results are in good agreement with the predictions of recent theoretical models relating DNA-DNA interactions to the helical symmetry of their surface charge patterns.     

Special Lagrangian Submanifolds with Isolated Conical Singularities. II. Moduli spaces

This is the second in a series of five papers studying special Lagrangiansubmanifolds (SLV m-folds) X in (almost) Calabi–Yau m-folds M with singularities x ₁ , ..., x _n locally modelled on specialLagrangian cones C ₁, ..., C _n in ^m with isolated singularities at 0.Readers are advised to begin with Paper V.This paper studies the deformation theory of compact SL m-folds X in Mwith conical singularities. We define the moduli space _X of deformations of X in M, and construct a natural topology on it. Then we show that _X is locally homeomorphic to the zeroes of a smooth map : _{X X} between finite-dimensional vector spaces.Here the infinitesimal deformation space _X depends only on the topology of X, and the obstruction space _X only on the cones C ₁, ..., C _n at x ₁, ..., x _n . If the cones C _i are stable then _X is zero, and _X is a smooth manifold. We also extend our results to families of almost Calabi–Yau structures on M.