Nucleotide probe

Molecular beacons are single-stranded hairpin-shaped nucleotide probes. In the presence of the target nucleotide sequence the molecular beacon unfolds, binds and fluoresces (Figure 6.13). 

There are only a few studies on the correlation between the expression of specific transcripts and freezing tolerance (see earlier), but nucleotide probes for these genes may contribute to selection schemes in breeding programmes. 

Figure 10 In situ identification of microbial aggregates consisting of Archea (red) in the center and SO -reducing bacteria (green) on the periphery. Microorganisms were labeled with rRNA-targeted oligio-nucleotide probes, (source Boetius et al., 2000b).

J. I. Morrell, Application of in situ Hybridization with Radioactive Nucleotide Probes to Detection of mRNA in the Central Nervous System, in Techniques in Immunocytochemistry, Vol. 4 (eds. G. R. Bullock and P. Petrusz), Academic Press, London, 1989, pp. 127-146. 

For example, they estimate that it would take about 10 minutes to reach complete hybridization of a 20-nucleotide probe. 

R. Higuchi, R. Watson, Kinetic PCR analysis using a CCD camera and without using oligo nucleotide probes. In PCR Applications (Eds. M.A. lnnis, D.H. Gelfand, J.J. Sninsky), Academic Press, San Diego, 1999, pp. 263-284. 

Microarrays are used for detection and quantification of the target gene using a DNA chip on which known DNA molecules are fixed. Complementary DNAs (cDNA) are reverse transcribed from RNAs isolated from culture samples, and the DNA extracted from environmental samples is hybridised to the nucleotide probes on the DNA chip. The signal intensities of these DNA-probe hybridised molecules are then detected using a fluorescence scanner. 

Very recently, polyacrylamide microlatexes prepared in the way described above have been used to microencapsulate certain types of rat cells [6.5]. These microcapsules are characterised by total absence of cell toxicity and the possibility of delaying antibody penetration in vitro. For these reasons, they may prove useful for encapsulating living cells. Also in the medical field of applications, water-in-oil microemulsion polymerisation has been used to synthesise functionalised nanoparticles with an enzyme immobilised inside them. These are used as a support in nucleotide probes [6.18]. 

DNA FISH (fluorescence in situ hybridization) Oligo nucleotide probe Targeted +... 

RNA In situ hybridization Ohgo nucleotide probe Targeted -1-... 

Fig. 6 In vitro transcription in a HeLa cell nuclear extract and SI nuclease mapping of RNA products. OVEC Spl template lane 1, control lane 2, with 50mM Zny-thionein lane 5, with 50mM thionein) SI probe, P-end-labeled 93 nucleotide probe extending between positions —18 and +75 of the noncoding strand of the J -globin gene. M/fapII-digested pBR 322 marker DNA. (Adapted from Fig. 2 of Zeng et al. 1991a)...

Quantitative PGR (Q-PGR or real-time PGR) detects specific DNA amplification products being formed by the polymerases. As with classic spectrophotometric methods, the signal arising from the bound fluorescently-labeled nucleotide probe increases in direct proportion to the amount of PGR product formed during reaction. Because the method is real-time, Q-PGR eliminates the need for post-PGR processing thus... 

FIGURE 20.4 (See color insert.) DNA Coating (1) interdigitated wires DNA strand. (2) Oligo-nucleotide probes primary ions applied. (3) Hybridized target secondary material developed on the primary. (Taken from Keren, K., Berman, R., Buchstab, E., Sivan, U., and Braun, E., 2003, Science, 302,1380-1382. With permission.)... 

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