**Author details**

Madan L. Nagpal University of South Carolina, Columbia, SC, USA

\*Address all correspondence to: madannag123@yahoo.com

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Synthetic Biology - New Interdisciplinary Science*

evolution and diversification of life.

fluorescent signaling as the amplification occurs [17].

protein expression was determined by fluorescence-activated cell sorting (FACS). The expression of CXCL10 was markedly enhanced in the transfected cells at mRNA and protein levels in the cells. Overexpression of CXCL10 inhibited cell proliferation of the transfected cells by 30–40% in serum-limited medium (1% FCS in RPMI1640 medium) and decreased PSA production. CXCR3 expression was significantly

induced by the overexpression of CXCL10 as determined by RT-PCR and FACS. These results indicated that CXCL10 inhibited LNCaP cell proliferation and decreased PSA production by upregulation of CXCR3 receptor. In conclusion, overexpression of CXCL10 may be potentially useful in the gene therapy of prostate cancer [14]. The identification of unknown organisms is carried out on genetic bases, whereas the molecular and chemical characteristics provide the complementary information. The DNA barcoding is one of the technologies for species classification and identification of unknown organisms. DNA barcoding involves tissue sample collection, DNA isolation, amplification of the isolated DNA, sequencing, and analyses of the results in order to identify the organism. The goal of DNA barcoding is to identify biological specimens using a short specific region of DNA. For example, a short fragment (658 bp) of mitochondrial gene cytochrome c oxidase I (COI) DNA from a single individual when amplified by polymerase chain reaction (PCR) was 100% successful in correctly identifying 200 closely allied species of Lepidoptera specimens [15]. Stoeckle and Thaler [16] pointed out that DNA barcode differences within animal species are usually much less than the differences among species, making it generally straightforward to match unknowns to a reference library. The barcodes could provide new insights and innovations into the

PCR is a technology to amplify a specific piece of DNA or gene and is used for analyses of genetic diseases, genetic fingerprinting, monitoring microbiological quality of food, detection and diagnosis of infectious diseases, and for many other uses. PCR is used to create copies of DNA for introduction into host organisms such as *Escherichia coli* in genetic engineering and to amplify stretches of genetic material for Sanger sequencing. PCR is used in archaeology, to identify human or animal remains, including insects trapped in amber, and to track human migration patterns; degraded DNA samples may be able to be reconstructed during the early cycles of PCR. PCR can be used to differentiate between similar organisms or work out relationships between different species (https://www.xxpresspcr.com). PCR technique was developed by Kary Mullis and his group in the 1980s, and in 1993, Kary Mullis and Michael Smith were awarded Nobel Prize in Chemistry for their work. The PCR technique involves the synthesis of a new strand of DNA complementary to the template strand using DNA polymerase and a set of primers. Since then a lot of progress has been made in this technique. Real-time PCR has been developed that monitors the progression of the amplification in real time by using

Using PCR technology, ribosomal RNA (rRNA) 16S–23S interspace region sequence variability in bacterial species was studied [18]. Two distinct genetic clusters within the species *Bacillus subtilis* and *Bacillus atrophaeus* were selected, and it was concluded that *B. atrophaeus* is distinct genetically from *B. subtilis* subgroups represented by W23 and 168, respectively. This was the first study to make sequence comparisons at the genome, strain, and species level for rRNA interspace region. Considerations of this issue will be important in using ribosomal space region (RSR) methodology to differentiate other closely related bacterial species.

Fox et al. [19] identified *Brucella* spp. by RSR PCR molecular technology and chemical characteristics as complementary information in the differentiation of closely related organisms. PCR products were unique to brucellae, allowing them to be readily distinguished from other gram-negative bacteria (including *Bartonella*

**6**
