Nucleic acid-based technologies

Nucleic acid-based technologies Nucleic acid probe Polymerase chain reaction, DNA amplication 16S rRNA sequencing techniques automated riboprinting... 

For convenience, the technologies are divided into growth-based technologies, viability-based technologies, cellular component or artifact-based technologies, and nucleic acid-based technologies as shown in Table 3. 

Nucleic acid-based technologies—DNA probe, ribotyping/molecular typing, and polymerase chain reaction... 

Even if It could be shown that RNA preceded both DNA and proteins in the march toward living things that doesn t automatically make RNA the first self replicating molecule Another possibility is that a self replicating polynucleotide based on some carbo hydrate other than o ribose was a precursor to RNA Over many generations natural selection could have led to the replacement of the other carbohydrate by D ribose giving RNA Recent research on unnatural polynucleotides by Professor Albert Eschenmoser of the Swiss Federal Institute of Technology (Zurich) has shown for example that nucleic acids based on L threose possess many of the properties of RNA and DNA... 

An additional example includes the intracellular transcription and translation of virally encoded genes during intracellular viral replication. In all such instances, the medical consequences of such inappropriate gene (over)expression could be ameliorated/prevented if this expression could be down-regulated. A nucleic-acid-based approach to achieve just this is termed antisense technology . 

RNAi technology has obvious therapeutic potential as an antisense agent, and initial therapeutic targets of RNAi include viral infection, neurological diseases and cancer therapy. The synthesis of dsRNA displaying the desired nucleotide sequence is straightforward. However, as in the case of additional nucleic-acid-based therapeutic approaches, major technical hurdles remain to be overcome before RNAi becomes a therapeutic reality. Naked unmodified siRNAs for example display a serum half-life of less than 1 min, due to serum nuclease degradation. Approaches to improve the RNAi pharmacokinetic profile include chemical modification of the nucleotide backbone, to render it nuclease resistant, and the use of viral or non-viral vectors, to achieve safe product delivery to cells. As such, the jury remains out in terms of the development and approval of RNAi-based medicines, in the short to medium term at least. 

Base pairing interaction between the nucleic acid strands forms the rationale for nucleic acid-based diagnostic and therapeutic technologies described in the subsequent chapters. 

Microarray is a rapidly developing field, with the capacity to revolutionize many fields of biomolecular research. This technology promises to deliver an explosion of information on the genetic basis of normal physiological processes and disease states by providing the opportunity to simultaneously compare the relative amounts of thousands of individual sequences from complex mixtures of nucleic acids. Based on traditional nucleic acid hybridization chemistry, it offers flexibility in choice of target/probe combinations and provides quantifiable data on relative expression levels. 

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