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Cyanines are indispensable fluorophores that form the chemical basis of many fluorescence-based applications. A feature that distinguishes cyanines from other common fluorophores is an exposed polyene linker that is both crucial to absorption and emission and subject to covalent reactions that dramatically alter these optical properties. Over the past decade, reactions involving the cyanine polyene have been used as foundational elements for a range of biomedical techniques. These include the optical sensing of biological analytes, super-resolution imaging, and near-IR light-initiated uncaging. This review surveys the chemical reactivity of the cyanine polyene and the biomedical methods enabled by these reactions. The overarching goal is to highlight the multifaceted nature of cyanine chemistry and biology, as well as to point out the key role of reactivity-based insights in this promising area.

Novel molecular platforms for epithelial sodium channel (ENaC) modulators are claimed in the following six patents: WO2012035158(A1); WO2009074575(A2); WO2011028740(A1); WO2009150137(A2); WO2011079087(A1); WO2008135557(A1). These ENaC inhibitors may be used in blocking transepithelial sodium and consequently water absorption across airway epithelia. This may result in airway rehydration and enhanced mucociliary clearance in patients with cystic fibrosis (CF) lung disease. All inhibitors resemble the classical ENaC blocker amiloride but follow different strategies to increase structural diversity in a sterically tolerant region. These substitutions can be modified to i) enhance potency of ENaC inhibition; ii) reduce epithelial permeability; and iii) broaden applicability in order to be used as potential drugs for CF therapy. Most of the claims and patent data are supported by the currently available literature. The patents deliver a solid chemical basis for a variety of chemical modifications of the ENaC i...

A survey is presented of the different modes of action of metal catalyst promotors. Broadly two main categories can be distinguished: structural and bifunctional promotors. In structural promotion the promoting atoms do not participate themselves in the elementary steps of a catalytic reaction. Bifunctional promotors participate themselves chemically in the catalytic reaction. Five different kinds of structural promotion can be recognized: ensemble-size regulating; valence-state promotion; polarizing-structural promotion; surface-phase and cluster complex promotion; particle size stabilizing. Each subcategory is discussed shortly and when relevant illustrated with a practical example. Three different kinds of bifunctional promotors can be distinguished: Polarizing-bifunctional promotion; direct-bifunctional promotion; chemical-bifunctional promotion. Whereas conceptually different, subcategories are not always easily experimentally distinguishable. Of most of the different kinds of promotion theoretical treatments exists. Quantum-chemical studies are referred to in the text.

Two new compounds, 5,6-dehydroaglajne-3 ( 9 ) and isopulo'upone ( 10 ), have been isolated and characterized, along with the already known niuhinone-B ( 7 ), from Navanax inermis and its prey Bulla gouldiana , firmly establishing on a chemical basis the predator - prey relationship between this pair of cephalaspidean opisthobranchs. The peculiarity of the metabolites and their structural analogy with other compounds isolated from other cephalaspidean molluscs assign a taxonomic relevance for them.

Prion-related diseases include scrapie in sheep, bovine spongiform encephalopathy in cattle and Creutzfeldt-Jakob disease in humans. The infectious agent for these diseases surprisingly contains no nucleic acid, but is a protein(PrP) which exists in two conformations, PrPC and PrPSc. The infectious PrPSc form has a higher β-sheet and lower α-helix content than PrPC. The structures of PrP and models for how PrPSc is able to replicate by converting PrPC to PrPSc are discussed.

Iron complexes with dithiocarbamates, Fe(DTC), and their nitrosyl complexes had been studied extensively until the 1970s because of their unique magnetic and electronic properties. In the 1990s, however, Fe(DTC) are commanding attention from a different point of view. In virtue of their high reactivity toward nitric oxide (NO) and the high stability of the resultant nitrosyl complexes which exhibit a characteristic electron paramagnetic resonance signal, Fe(DTC) have been used for the detection and analysis of biological NO produced endogenously from NO synthases. We have studied the chemical basis of this detection method and its application. In spite of the method’s widespread use, the chemical basis seems to be very poor. We, therefore, review the fundamental data on Fe(DTC) species and their reaction with NO, including the novel reductive nitrosylation mechanism realized in this system.

This review describes work on the conformational stability of the collagen triple helix. In 1994, the structure of collagen was determined at high resolution. Since then, much work has been done on synthetic mimics of collagen that contain host-guest peptides, tethers, peptoid residues, or analogs of the prevalent 4(R)-hydroxy-L-proline residues. This work has revealed much about the chemical basis for collagen stability, and could spawn useful new biomaterials. The literature from 1994 to mid 2001 is reviewed, and 116 references are cited.

The development of a reaction for the detection of the presence/absence of one methyl group in a very long DNA strand is a chemically and biologically challenging research subject. Several newly designed chemical assays for the typing of DNA methylation are reported and discussed in this paper. A new concept of sequence-specific short-term methylation analysis, supported by a chemical basis, is the starting point for a novel methylation-typing assay, which will supersede conventional methods.

The isolation of morphine (‘principium somniferum’) by Friedrich Wilhelm Serturner about 200 years ago is generally accepted as the beginning of scientific phytochemistry (plant secondary products research). For about 150 years this research addressed almost exclusively the isolation and structure elucidation of new plant products. It had great impact on the development of modern organic chemistry and pharmaceutical industry and provided the chemical basis for biological research on plant secondary metabolism, which began about 50 years ago. The historical development of this field to its present state of knowledge will be considered in this review from three angles of vision: mechanistic, functional and evolutionary perspectives. Mechanistic research started on the metabolite level and was initiated by the availability of radioactive nuclides in the early 1950s. By means of sophisticated tracer techniques, the biosynthetic routs of most secondary pathways were outlined and provided the basis for the enzymatic characterization of biosynthetic pathways in the 1970s and 1980s, followed by the identification of the corresponding genes beginning in the late 1980s. During this 50-year period of intensive research a change of paradigm occurred addressing the question: why do plants synthesize this immense rich diversity of secondary metabolites comprising more than 200,000 structures? For a long time regarded as waste products or assigned with various other attributes their indispensable role as components of the survival strategy of plants in a mostly hostile environment appears now generally accepted. Along with the great progress in the field of chemical ecology, the emerging field of molecular evolution provided crucial evidence that during evolution of secondary metabolism genes encoding enzymes of plant’s primary metabolism were duplicated, recruited and diversified for new functions under the everlasting and continuously changing selection pressure of the environment.