Metals in Biological Systems A Survey

Metals in biological systems function in a number of different ways. Group 1 and 2 metals operate as structural elements or in the maintenance of charge and osmotic balance (Table 1.2). Transition metal ions that exist in single oxidation states, such as zinc(II), function as structural elements in superoxide dismutase and zinc fingers, or, as an example from main group +2 ions, as triggers for protein activity—that is, calcium ions in calmodulin or troponin C 

TABLE 1.2 Metals in Biological Systems Charge Carriers 

Metal Number, Geometry Preferred Ligands Functions and Examples 

Sodium, Na 6, octahedral O-Ether, hydroxyl. Charge carrier, osmotic 

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METALS IN BIOLOGICAL SYSTEMS A SURVEY TABLE 1.4 Metals in Biological Systems Electron Transfer... 

Because of the use of various electrolyte systems, pH gradients, and not least an electric field, some complexes would not survive the separation. It is therefore necessary that the species to be separated are both thermodynamically and kineti-cally stable. Recently, Bocek and Foret have reviewed the application of isotachophoresis to the separation of inorganic species. This technique appears to be well-suited for the study of the distribution of metabolites of metal-containing drugs in body fluids. A survey of the application of electrophoretic techniques to biological materials can be found in the book edited by Deyl... 

In the first chapter, Uosaki and Kita review various theoretical models that have been presented to describe the phenomena that occur at an electrolyte/semiconductor interface under illumination. In the second chapter, Orazem and Newman discuss the same phenomena from a different point of view. In Chapter 3, Boguslavsky presents state-of-the-art considerations of transmembrane potentials and other aspects of active transport in biological systems. Next, Burke and Lyons present a survey of both the theoretical and the experimental work that has been done on hydrous oxide films on several metals. 

In fact, of all the methods surveyed, NMR is the most versatile and powerful (although not the most sensitive). If future developments bring about major improvements in its sensitivity, NMR microscopy, in which NMR spectra of different compartments in a biological specimen can be recorded in vivo, could provide a new oudook on the determination of metal speciation in natural systems. 

Pyridines and their benzo-derivatives have played an important role in the synthesis of biologically active synthetic and natural substances. As a result, the construction of this molecular architecture has attracted the attention of a diverse array of synthetic methodologies. Notably, transition metal catalysis, radical reactions and cycloaddition chemistry-based methods have been developed for the construction of this important ring system. Detailed herein is a summary of the methods developed for the synthesis of pyridines, quinolines, isoquinolines and piperidines that were disclosed in the literature in 2002. Rather than survey all existing methods for the construction of these compound classes, this review will serve as a supplement and update to the review published last year in this series. 

Unlike the Pfeiffer-induced systems discussed in Section 3.4.1, this section details some of the successful recent examples demonstrating the design principles for targeting anions and/or proteins that are of biological relevance [direct coordination to the metal centre of the chiral Ln(III)-based probes], followed by a survey of similar studies for analyte sensing (i.e. cations and/or proteins) in which the coordination occurs between the analytes and some of the antenna/receptor groups of the chiral Ln(III)-based probes. 

The use of filtration to polish biological treatment system effluent has become more popular in recent years because of more stringent discharge requirements. The 1977 EPA survey of petroleum refineries indicated that 27 of 259 plants used filtration as part of the existing treatment scheme and 16 others planned to install filtration systems in the near future [5]. Filtration can improve effluent quality by removing oil, suspended solids, and associated BOD and COD, and carryover metals that have already been precipitated and flocculated. Improved effluent filtration in one recent instance helped a Colorado refinery to meet the newly adopted discharge toxicity requirements [49]. 

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