Topoisomerase II is the target for several highly active anticancer drugs that induce cell death by enhancing enzyme-mediated DNA scission. Although these agents dramatically increase levels of nucleic acid cleavage in a site-specific fashion, little understood regarding mechanism which they alter site selectivity topoisomerase II. Therefore, series kinetic and binding experiments were carried out to determine mechanistic basis drug, etoposide, enhances complex formation at 22 specific...

Although a number of drugs currently in use for the treatment human cancers act by stimulating topoisomerase II-mediated DNA breakage, little is known regarding interactions between these agents and enzyme. To further define mechanism drug action, ellipticine (an intercalative with clinical relevance) yeast II were characterized. By utilizing genetic system, was identified as primary cellular target drug. Furthermore, did not inhibit enzyme-mediated religation, suggesting that it stimulates...

Abstract Hydrogels with four different plant‐based microcrystalline cellulose concentrations were prepared using the self‐assembly technique. The interaction parameter between and water was determined by classical Flory‐Huggins theory, found to be around 0.44 weak concentration dependence. crosslinking density in these hydrogels measured both Mooney‐Rivlin equation Flory‐Rehner theory. Reasonable consistency two methods albeit results from theory slightly higher due contribution physical...

Microencapsulation technology has been increasingly applied toward the development of self-healing paints. Added to paint as a dry powder prior spraying, microcapsules store liquid that can repair protective barrier layer if released into scratch. However, will not occur unless withstand spray-painting, aggressive solvents in paint, and long-term exposure elements. We have therefore developed one-pot synthesis for production Pickering with outstanding strength, solvent resistance,...

Given the avid and selective metal binding properties of naturally-occurring metalloproteins, it is possible to exploit these systems in development novel sensors, i.e., "biosensors", for detection trace quantities ions. Here, we high affinity human carbonic anhydrase II (CAII) zinc nanomolar concentrations this ion by fluorescence anisotropy using a fluorescein-derivatized arylsulfonamide probe, 4-aminosulfonyl[1-(4-N-(5-fluoresceinylthioureido)butyl)]benzamide (3). This probe was designed...

A moisture-sensitive diisocyanate liquid is microencapsulated within a metal shell measuring less than 2 μm thick and 50 in diameter. This mild synthesis takes place through series aqueous processing steps that occur at or near room temperature. Through combination of emulsification, interfacial polymerization, electroless plating, one can microencapsulate moisture- air-sensitive chemicals seal. The liquid-filled microcapsules promise number advantages compared to conventional polymeric...

Microtubules formed from diacetylenic phosphatidyl-cholines can be made rugged and solvent resistant through electroless deposition of metals (Rudolph et al. 1990). Once dried tubules capture a range materials by capillary action when added to hydrating medium, thus retaining controlling the release rates these materials. We report encapsulation in mixture tetracycline, epoxy monomers polymers their vitro kinetics both dynamic static environments.

Microencapsulation of natural antifouling compounds and their subsequent inclusion in polymeric coatings is a viable alternative to self‐polishing paint or rosin‐based ablative coatings. However, as naturally occurring compounds, the crude extracts Octocorals (Renilla reniformis) Pukalides, while found be effective agents, are subject both photolysis chemical degradation marine environment. For these provide persistent metallic toxicants such organotins, they must stabilized coating released...

Prompt emergency treatment for ocular injury, particularly in a battlefield setting, is essential to preserve vision, reduce pain, and prevent secondary infection. A bandage contact lens that could be applied the field, at time of would protect injured surface until hospital available. Cellulose, natural polymer, widely used biomedical applications including materials. Hydrogels synthesized from different cellulose sources, such as plants, cotton, bacteria, can have optical transparency...

Rapidly curing underwater adhesives were tested on untreated substrates and demonstrated high ultimate shear strength. An isocyanate resin was combined with microcapsules containing both a polyol crosslinker tertiary amine catalyst. The polyurea synthesized large scale via an inverse Pickering emulsion utilizing inexpensive reagents. stable to ambient conditions gentle mixing but released their contents when appropriate shearing forces applied. final polyurethane adhesive achieved bonding...

ABSTRACT Cellulose‐based hydrogels show great potential for a wide range of applications. However, the structure these hydrated gels is not fully understood. The impact moisture on and stability cellulose based reported in this article. Analytical data GPC, NMR, rheology are discussed. It was found that moisture‐induced gelation greatly reduces crystallinity hydrogels, release water from leads to permanent structural changes network due reformation hydrogen bonding. © 2015 Wiley Periodicals,...

Painting is a cost-effective technique to delay the onset of corrosion in metals. However, protection only temporary, as begins once coating becomes scratched. Thus, an increasingly common practice add microencapsulated chemical agents paint order confer self-healing capabilities. The additive's ability protect exposed surface from depends upon (i) how long agent takes spread across metal; (ii) form effective barrier layer; and (iii) what happens metal before first two steps are complete. To...

We have recently described a biosensor for zinc and other metals which is based upon fluorescence energy transfer from site or sites on the enzyme carbonic anhydrase to an inhibitor whose binding active largely metal-dependent. The concentration of metal ion analyte simple function occupancy by colored inhibitor, transduced as change in intensity lifetime fluorescent donor. others demonstrated assays several analytes with moderate success. In this work we demonstrate simulation experiment...

Altered sensitivity of topoisomerase II to anticancer drugs profoundly affects the response eukaryotic cells these agents. Therefore, several approaches were employed elucidate mechanism drug hypersensitivity mutant yeast type topoisomerase, top2H1012Y. This mutant, which is ~5-fold hypersensitive ellipticine, formed DNA cleavage complexes more rapidly than wild-type enzyme in presence drug. Conversely, no change rate religation was observed. There was, however, a correlation between...

Many natural products that exhibit biocidal activity have poor solubility in water. In order to explore the prolonged delivery of these compounds from microtubules we utilized 2-methoxynaphthalene as a model elucidate release characteristics hydrophobic entrapped by spectrophotometric absorbance at 255 nm. Entrapment this compound microcylinders was accomplished addition watersoluble epoxy, or entrapment neat compound. Variation rate is possible for based on mode and variations methods used...

Recently, we have developed a biosensor for zinc based on the very tight binding of this metal by enzyme carbonic anhydrase, which requires Zn(II) catalysis. We were able to transduce as change in fluorescence intensity or lifetime use colored inhibitor whose metal-dependent permits resonance energy transfer (Forster transfer) occur. extended concept include other metals and analytes may be bound native (or mutant) active site with concomitant color change; is transduced efficiency. also...

Recently, we have demonstrated a fluorescence-based fiber optic biosensor for zinc in aqueous solutions. Binding of to the active site human apocarbonic anhydrase II is transduced by subsequent binding fluorescent inhibitor, dansylamide, situ, resulting large changes wavelength, quantum yield and lifetime danslamide emission. These fluorescence can be readily measured through optical fiber, subnanometer detection limits 50 dB dynamic range with excellent selectivity. However, dansylamide...