The exciting discovery of the semiconducting-like properties of deoxyribonucleic acid (DNA) and its potential applications in molecular genetics and diagnostics in recent times has resulted in a paradigm shift in biophysics research. Recent studies in our laboratory provide a platform towards detecting charge transfer mechanism and understanding the electronic properties of DNA based on the sequence-specific electronic response, which can be applied as an alternative to identify or detect DNA. In this study, we demonstrate a novel method for identification of DNA from different shrimp viruses and bacteria using electronic properties of DNA obtained from both negative and positive bias regions in current-voltage (I–V) profiles. Characteristic electronic properties were calculated and used for quantification and further understanding in the identification process. Aquaculture in shrimp industry is a fast-growing food sector throughout the world. However, shrimp culture in many Asian countries faced a huge economic loss due to disease outbreaks. Scientists have been using specific established methods for detecting shrimp infection, but those methods do have their significant drawbacks due to many inherent factors. As such, we believe that this simple, rapid, sensitive and cost-effective tool can be used for detection and identification of DNA from different shrimp viruses and bacteria.

Aims:The goal of the study is to isolate new bacteria species which are capable to utilizing 2,2-dichlropropionic acid (2-2-DCP) as a sole carbon source from the wastewater sample that was taken from Tioman Island off the coast of Malaysia. Methodology and results: Genomic DNA from unknown bacterial strain (MR1) was extracted and PCR amplification was carried out using universal primers, Fd1 (5'-AGA GTT TGA TCC TGGCTC AG-3') and rP1 (5'-ACG GTC ATA CCT TGT TAC GAC TT-3') prior to sequencing. The BLASTn and phylogenetic analysis of the 16S rRNA of the MR1 gene found it shares a 95% homology to an aerobic bacillus Raoutella ornithilolytica. The bacteria which is usually found in an aquatic and hospital environment was found to possess a distinctive feature of being able to utilize 2,2-DCP as sole carbon source. The bacteria has cell doubling time of 23.11 h and maximum release of chloride ion at 0.257 mmol/L in 20 mM 2,2-DCP. Based on morphological and partial biochemical characteristics, the strain was found to be non-motile, Gram negative bacteria with red colonies that gave a positive catalase reaction. Conclusion, significance and impact of study: A better understanding of newly isolated microorganisms from the environment which can potentially be used as bioremediation tools in environmental management. This is the first reported case of Raoutella sp. that has the unique ability to degrade halogenated compound. Hence, the dehalogenation properties and capabilities of the bacteria deserve to be assessed further.

Figure 5. (a) Photograph and (b) schematic diagram of the DNA-specific Schottky diode fabricated for the study while (c) represents the equivalent electrical circuit.