Acids hybridization and

Two principal types of nucleic acid-based methods, nucleic acid hybridization and polymerase chain reaction (PCR), are commonly used for the rapid identification of bacteria. A few other nucleic acid-based methods will also be mentioned. 

Diamandis, E.P. (1993) Time-resolved fluorometry in nucleic acid hybridization and Western blotting techniques (Review). Electrophoresis 14, 866-875. 

Monath TP, Ballinger ME, Miller BR, et al. Detection of yellow fever viral RNA by nucleic acid hybridization and viral antigen by immunohistochemistry in fixed human liver. Am J Trap Med Hyg. 1989 40 663-668. 

Similar techniques are used for the demonstration of other cytochemical affinity reactions, such as in nucleic acid hybridization and in the binding of lectins, hormones and other substances. I refer to these techniques as indirect fluorochromy, since the fluorochrome is bound indirectly (through at least one intermediate molecule) to the substrate (the substance intended to be stained). Immunofluorescence, nucleic acid hybridization and similar affinity reactions have made an enormous contribution to cell biology. 

Antony, T. Subramaniam, V. Molecular beacons nucleic acid hybridization and emerging applications. J. Biomol. Struct. Dyn. 2001, 19, 497-504. 

Fig. 1. Southern blot analysis of DNA showing (a) step 1, an agarose gel containing separated restriction fragments of DNA, denoted by (—), which is immersed in NaOH to denature the double-stranded stmcture of DNA, and then transferred by capillary flow to a nitrocellulose filter. In step 2, the bound DNA is allowed to hybridize to a labeled nucleic acid probe, and the unbound probe is washed off In step 3, the filter is placed into contact with x-ray film resulting in (b) bands of exposure on the film which are detected after development and correspond to regions where the restriction fragment is...

Carboxylic acids are similar in some respects to both ketones and alcohols. Like ketones, the carboxyl carbon is sp2-hybridized, and carboxylic acid groups are therefore planar with C-C=0 and 0=C-0 bond angles of approximately 120° (Table 20.2). 

The a carbon of mandelic acid is sp hybridized. The corresponding carbons of both a-phenylglycidic acid, 49, and the carbanion intermediate 48 are neither sp hybridized nor sp hybridized, but presumably between these two extremes. It is therefore possible that the a-phenylglycidic acid is restricted to a conformation which resembles a transition state in the racemization process, a transition state which would have much of the character of the intermediate 48, and for which the enzyme would presumably have a high affinity (1). 

O. G. PNA-related oligonucleotide mimics and their evaluation for nucleic acid hybridization studies and analysis. Nucleosides, Nucleotides Nucleic Acids 2001 20 419-428. 

All of the hybridization procedures discussed in this section depend on the specific base-pairing properties of complementary nucleic acid strands described above. Perfect matches hybridize readily and withstand high temperatures in the hybridization and washing reac-... 

One of the most interesting recent developments has been the advent of the resin glass polyalkenoate cements (Antonucci, McKinney Stansbury, 1988 Mitra, 1989 Wilson, 1989, 1990 Mathis Ferracane, 1989 Minnesota Mining Manufacturing Company, 1989 Albers, 1990). They are dual-cure hybrids that set by a combination of acid-base and polymerization reactions, and there are several types. Polymerization is effected by either chemical or light initiation. 

The difficulty with protein arrays is that proteins do not behave as uniformly as nucleic acid. Protein function is dependent on a precise, and fragile, three-dimensional structure that may be difficult to maintain in an array format. In addition, the strength and stability of interactions between proteins are not nearly as standardized as nucleic acid hybridization. Each protein-protein interaction is unique and could assume a wide range of affinities. Currently, protein expression mapping is performed almost exclusively by two-dimensional electrophoresis and mass spectrometry. The development of protein arrays, however, could provide another powerful... 

Fig. 4 Flavin amino acids FI and F2 used for the preparation of DNA PNA hybrid duplexes. These duplexes possess the flavin in the PNA strand and the backbone opened dimer in the DNA strand. a Indicates unstructured melting. M.p.= melting points of the constructs...

Nucleic acid hybridization methods use oligonucleotide DNA probes with sequences complementary to a portion of the nucleic acid of the target bacterium38,60 and designed to hybridize with immobilized DNA or RNA on a membrane. After any unbound probe has been washed off, the hybridized probe can be detected.64 66... 

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