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Major stumbling blocks in the production of fully synthetic materials designed to feature virus recognition properties are that the target is large and its self-assembled architecture is fragile. Here we describe a synthetic strategy to produce organic/inorganic nanoparticulate hybrids that recognize non-enveloped icosahedral viruses in water at concentrations down to the picomolar range. We demonstrate that these systems bind a virus that, in turn, acts as a template during the nanomaterial synthesis. These virus imprinted particles then display remarkable selectivity and affinity. The reported method, which is based on surface imprinting using silica nanoparticles that act as a carrier material and organosilanes serving as biomimetic building blocks, goes beyond simple shape imprinting. We demonstrate the formation of a chemical imprint, comparable to the formation of biosilica, due to the template effect of the virion surface on the synthesis of the recognition material.

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f Sulfonamide antibiotics have a wide application range in human and veterinary medicine. Because they tend to persist in the environment, they pose potential problems with regard to the propagation of antibiotic resistance. Here, we identified metabolites formed during the degradation of sulfamethoxazole and other sulfonamides in Microbacterium sp. strain BR1. Our experiments showed that the degradation proceeded along an unusual pathway initiated by ipso-hydroxylation with subsequent fragmentation of the parent compound. The NADH-dependent hydroxylation of the carbon atom attached to the sulfonyl group resulted in the release of sulfite, 3-amino-5-methylisoxazole, and benzoquinone-imine. The latter was concomitantly transformed to 4-aminophenol. Sulfadiazine, sulfamethizole, sulfamethazine, sulfadimethoxine, 4-amino-N-phenylbenzenesulfonamide, and N-(4-aminophenyl)sulfonylcarbamic acid methyl ester (asulam) were transformed accordingly. Therefore, ipso-hydroxylation with subsequent fragmentation must be considered the underlying mechanism; this could also occur in the same or in a similar way in other studies, where biotransformation of sulfonamides bearing an amino group in the para-position to the sulfonyl substituent was observed to yield products corresponding to the stable metabolites observed by us. Sulfonamides are widely used as antibiotics, antidiabetics, diuretics, antivirals, and anticancer agents (1-4), and thus, large amounts of these compounds enter the environment every year (5, 6). Contamination with sulfonamides poses environmental concern due to the potential development and dissemination of antibiotic resistances (7). Despite their ubiquity, their microbial metabolism and ultimate fate in the environment thereof are poorly understood.Several studies showed that sulfamethoxazole (SMX) (Fig. 1a), an important representative of sulfonamide compounds, undergoes partial degradation in wastewater treatment plants under aerobic and anaerobic conditions (8-11). We recently demonstrated that Microbacterium sp. strain BR1, a Gram-positive bacterium isolated from a membrane bioreactor treating effluent contaminated by several pharmaceuticals, was capable of mineralizing the 14 C-labeled aniline moiety of SMX when the latter was supplied as the sole carbon source (12). This was the first unambiguous indication that sulfonamides are subject to growth-linked metabolism in microorganisms.To our knowledge, Hartig (13) was the first to identify the aminated heteroaromatic side moieties of the sulfonamides SMX and sulfadimethoxine as stable metabolites after biodegradation with activated sludge. This result was recently confirmed by two groups that were able to isolate Microbacterium strains with the ability to degrade the sulfonamides sulfamethazine (SMZ) (14) and sulfadiazine (SDZ) (15). Additionally, both groups identified the aminated heteroaromatic side moieties of the sulfonamide as a stable metabolite after the degradation of the parent compound. Although these stable metabolites were identified, the i...

Abstract:In view of the chiral nature of many bio-molecules (and all bio-macromolecules), most of therapeutically active compounds which target these molecules need to be chiral and "good handed" to be effective. In addition to asymmetric synthetic and separation methodologies, enantioselective chemical sensors, able to distinguish between two enantiomers of the same molecule, are of relevance. In order to design these sensing tools, two major classes of enantioselective layers have been developed. The first is based on molecularly imprinted polymers which are produced (polymerized) in the presence of their target, thus the polymeric material keep in "memory" the size and the shape of this molecule and the system could be used for sensing (not reviewed here). The second approach makes use of sensitive layers containing chiral macrocyclic receptors able of stereoselective molecular recognition; these receptors are mainly based on cyclodextrins. In this contribution, are reviewed achievements in the use of native or chemically modified cyclodextrins for chiral sensing purposes (at interfaces). Potentialities of other chiral macrocycles based on calixarenes, calix-resorcinarenes or crown-ethers as supramolecular receptors for enantioselective sensing are discussed.

The calixarenes and resorcinarenes are macrocyclic phenolic molecules that can be modified ''a`fac ¸on'' and a wide range of chemical modification strategies have been published over the last 30 years. Because of their remarkable structural properties and their relative ease of chemical modification, they represent excellent and highly versatile bases to design complex building blocks capable of self-assembly and molecular recognition. They have been widely studied for their ability to form supramolecular structures targeting a wide range of applications. The possibility to regio(rim)-selectively modify these macrocycles with different polar and apolar moieties provides synthetic chemists with an unlimited range of possibilities for the design of complex amphiphiles with a high control over the position of the grafted moieties in the three dimensions. These amphiphiles have been shown to possess outstanding self-assembling and/or molecular recognition properties. This short review describes the developments of the chemistry of amphiphilic calixarenes and resorcinarenes with a clear focus on the synthetic paths used for their production and their self-assembly properties in water.

A trifunctional, partially fluorinated anthracene-substituted triptycene monomer was spread at an air/water interface into a monolayer, which was transformed into a long-range-ordered 2D polymer by irradiation with a standard UV lamp. The polymer was analyzed by Brewster angle microscopy, scanning tunneling microscopy measurements, and non-contact atomic force microscopy, which confirmed the generation of a network structure with lattice parameters that are virtually identical to a structural model network based on X-ray diffractometry of a closely related 2D polymer. The nc-AFM images highlight the long-range order over areas of at least 300×300 nm . As required for a 2D polymer, the pore sizes are monodisperse, except for the regions where the network is somewhat stretched because it spans over protrusions. Together with a previous report on the nature of the cross-links in this network, the structural information provided herein leaves no doubt that a 2D polymer has been synthesized under ambient conditions at an air/water interface.

We report a cluster of genes encoding two monooxygenases (SadA and SadB) and one FMN reductase (SadC) that enable Microbacterium sp. strain BR1 and other Actinomycetes to inactivate sulfonamide antibiotics. Our results show that SadA and SadC are responsible for the initial attack of sulfonamide molecules resulting in the release of 4-aminophenol. The latter is further transformed into 1,2,4-trihydroxybenzene by SadB and SadC prior to mineralization and concomitant production of biomass. As the degradation products lack antibiotic activity, the presence of SadA will result in an alleviated bacteriostatic effect of sulfonamides. In addition to the relief from antibiotic stress this bacterium gains access to an additional carbon source when this gene cluster is expressed. As degradation of sulfonamides was also observed when Microbacterium sp. strain BR1 was grown on artificial urine medium, colonization with such strains may impede common sulfonamide treatment during co-infections with pathogens of the urinary tract. This case of biodegradation exemplifies the evolving catabolic capacity of bacteria, given that sulfonamide bacteriostatic are purely of synthetic origin. The wide distribution of this cluster in Actinomycetes and the presence of traA encoding a relaxase in its vicinity suggest that this cluster is mobile and that is rather alarming.