Hybridization. Hybridization techniques can be used in bacterial identification either alone or combined with a preceding PCR step. In hybridization, a labeled probe anneals to a denatured target DNA / RNA with sequence homology (Southern 1975, Xxxxxx et al. 1977). Target DNA / RNA can be directly blotted onto a membrane, or if size information of the hybridization target is war- ranted, the target DNA / RNA is first run through an agarose gel with DNA markers of a spe- cific size and then transferred to a membrane. Detection of hybrids is based on radioactive signal, fluorescence, or color reaction, depending on the type of label. By determining the intensity of the hybridization signal, the number of target organisms can be estimated (Xxxxx et al. 1988). However, it should be noted that the relative amount of an rRNA sequence does not reflect the true abundance of the microbe, since the amount of rRNA per cell varies ac- cording to the species and the metabolic activity of the bacterial cell (Xxxxxxxxxxx et al. 2000). Nevertheless, the relative quantity of rRNA provides a reasonable measure of the relative physiological activity of a specific population (Xxxxxxx et al. 2000). Microarrays, which are miniaturized and automated forms of a dot-blot hybridization, facilitate the study of large numbers of genes simultaneously by hybridization of DNA or mRNA to a high-density array of immobilized probes (Xxxxx et al. 1993, Xxxxxx et al. 1995, Xxxxxxxx et al. 1996). There are two major types of DNA microarrays; an oligonucleotide-based array and a PCR product-based array. The detection of whole bacterial cells via labeling of specific nucleic acids with fluorescently labeled oligonucleotide probes is called fluorescent in situ hybridization (FISH). FISH requires no cultivation and cells can be fixed before analysis, thus enabling the storage of samples prior to analysis (XxXxxx et al. 1989, Xxxxx et al. 1990). The whole-cell or in situ hybridization technique has become a much used molecular tool in microbial ecology, since organisms or groups of organisms can be identified with minimal disturbance of their environment and spatial distribution.
Hybridization. The complete process of hybridization involved the combining of the prepared library with the hybridization and blocking agents and the SureSelect capture library as demonstrated below (Figure 8).
Hybridization. 1. ISU shall provide HHS with documentation designating it a hybrid entity and identifying all of its components that have been designated covered health care components within 30 days of the Effective Date.
