The nature and properties of surface-enhanced vibrational spectra of molecules adsorbed on surfaces that can enhance the absorption and the emission of electromagnetic radiation are discussed. Examples of surface-enhanced resonant Raman scattering, surface-enhanced Raman scattering in the near-infrared and surface-enhanced infrared are given. The rough surfaces used are metal island films coated with a nanometric organic film using the Langmuir-Blodgett technique or deposited by vacuum evaporation.

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Surface enhanced vibrational spectroscopy

This article provides an overview of the development and application of the surface-enhanced Raman scattering (SERS) techniques using metal-coated nanostructures on solid substrates An introduction to theoretical principles of the SERS effect and the different SERS-active media is presented The focus is on nanostructured solid substrates and their practical applications in chemical, environmental and biomedical areas Specific examples of analytical techniques, instruments and sensors developed in the author's laboratory will be discussed to illustrate the usefulness and potential of the SERS techniques

Surface-enhanced Raman spectroscopy using metallic nanostructures

Transfer RNA (tRNA) from all organisms on this planet contains modified nucleosides, which are derivatives of the four major nucleosides. tRNA from Escherichia coli/Salmonella enterica contains 31 different modified nucleosides, which are all, except for one (Queuosine[Q]), synthesized on an oligonucleotide precursor, which through specific enzymes later matures into tRNA. The corresponding structural genes for these enzymes are found in mono- and polycistronic operons, the latter of which have a complex transcription and translation pattern. The syntheses of some of them (e.g.,several methylated derivatives) are catalyzed by one enzyme, which is position and base specific, but synthesis of some have a very complex biosynthetic pathway involving several enzymes (e.g., 2-thiouridines, N6-threonyladenosine [t6A],and Q). Several of the modified nucleosides are essential for viability (e.g.,lysidin, t6A, 1-methylguanosine), whereas deficiency in others induces severe growth defects. However, some have no or only a small effect on growth at laboratory conditions. Modified nucleosides that are present in the anticodon loop or stem have a fundamental influence on the efficiency of charging the tRNA, reading cognate codons, and preventing missense and frameshift errors. Those, which are present in the body of the tRNA, have a primarily stabilizing effect on the tRNA. Thus, the ubiquitouspresence of these modified nucleosides plays a pivotal role in the function of the tRNA by their influence on the stability and activity of the tRNA.

Transfer RNA Modification

Studies on polynucleotides. X. Enzymic degradation. Some properties and mode of action of spleen phosphodiesterase.

Publisher Summary This chapter describes a general method, which has made possible the sequence analysis of tRNAs from mitochondria, chloroplasts, and a wide variety of prokaryotic and eukaryotic organisms using in some cases as little as 20μg of purified tRNA. The development of in vitro 32 P-labeling techniques has now permitted sequence analysis of nonradioactive tRNAs utilizing adaptations of methods developed by Sanger and co-workers for analysis of uniformly 32 P-labeled RNAs. oligonucleotides with a free 5'-hydroxyl end which are present in digests of nonradioactive nucleic acids can be labeled to high specific activity using T4 polynucleotide kinase and [γ- 32 P]ATP. This approach is used for labeling with 32 P the 5' ends of both mononucleotides present in complete tRNA hydrolysates and oligonucleotides present in T1 or pancreatic RNase digests of tRNA. Using oligonucleotides present in tRNAs of known sequence as standards, the mobility shifts of many commonly occurring modified nucleotides are characterized, which has proved useful in recognizing these modified nucleotides within unknown sequences. The basic steps in the sequence analysis of a nonradioactive tRNA are summarized in the chapter.

Use of in vitro 32P labeling in the sequence analysis of nonradioactive tRNAs.

Rapid ion-exchange chromatographic microanalysis of ultraviolet-absorbing materials and its application to nucleosides☆

Benzo[a]pyrene-7,8-diol-9,10 epoxide (BPDE)-DNA adducts have been analyzed by surface-enhanced Raman scattering (SERS) spectrometry. BPDE is the ultimate carcinogenic metabolite of benzo[a]pyrene. The SERS measurements were performed with the use of a silver-coated cellulose material as the SERS-active substrate. The acid hydrolyzed products of BPDE-DNA adducts, DNA, and the BP-tetrols were also analyzed by SERS. The results indicate that SERS has great promise as a tool for detecting BPDE-DNA adducts in biological samples.

Surface-Enhanced Raman Analysis of Benzo[A]Pyrene-DNA Adducts on Silver-Coated Cellulose Substrates:

Desalting of nucleotides by gel filtration.

Isolation and characterization of pyrimidine sulfenic acid via scission of the sulfur-sulfur bond in the methyl analog of bis(4-thiouridine) disulfide.

Mayo Uziel

Papers

Rapid ion-exchange chromatographic microanalysis of ultraviolet-absorbing materials and its application to nucleosides☆

Surface-Enhanced Raman Analysis of Benzo[A]Pyrene-DNA Adducts on Silver-Coated Cellulose Substrates:

Desalting of nucleotides by gel filtration.

Isolation and characterization of pyrimidine sulfenic acid via scission of the sulfur-sulfur bond in the methyl analog of bis(4-thiouridine) disulfide.

The use of the cetyltrimethylammonium cation in terminal sequence analyses of ribonucleic acids.