Optical Aptasensors and the Challenge of Food Contamination With Lead

Contamination of heavy metals in food, especially drinking water and groundwater, has become a serious problem for human health. These metals are mainly the constituent elements of nature widely distributed in the earth's crust, but significant amounts of them are also found in everyday goods. These elements are usually found in combinations with oxygen, chlorine, sulfur, and other anions that generally contain inorganic and organic compounds. Lead is one of the heavy metals with high toxicity that poses serious risks to the environment and humans. Recent advances in nucleic acid research have led to the identification of oligonucleotide sequences that bind with high affinity specifically to target molecules, including proteins. Such single-stranded sequences are called "aptamer" nucleic acids. Aptamers are synthetic single-stranded DNA or RNA sequences of 30 to 100 nucleotides, and their secondary and tertiary structures are folded to make them highly specific for binding to targets. The binding of aptamers to different targets, from a single cell to large chemical and biological molecules, is done with high affinity. This aptamer feature is used to detect lead. In this review article, the designed optical aptasensors for the detection of lead will be reviewed.

Role of RNA Oxidation in Neurodegenerative Diseases

In the history of nucleic acid research, DNA has always been the main research focus. After the sketch of the human genome was completed in 2000, RNA has been started to gain more attention due to its abundancies in the cell and its essential role in cellular physiology and pathologies. Recent studies have shown that RNAs are susceptible to oxidative damage and oxidized RNA is able to break the RNA strand, and affect the protein synthesis, which can lead to cell degradation and cell death. Studies have shown that RNA oxidation is one of the early events in the formation and development of neurodegenerative disorders, including Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis. However, its molecular mechanism, as well as its impact on these diseases, are still unclear. In this article, we review the different types of RNA oxidative damage and the neurodegenerative diseases that are reported to be associated with RNA oxidative damage. In addition, we discuss recent findings on the association between RNA oxidative damage and the development of neurodegenerative diseases, which will have great significance for the development of novel strategies for the prevention and treatment of these diseases.

Molecular beacons: a new approach for semiautomated mutation analysis

Molecular beacons are oligonucleotide probes that become fluorescent upon hybridization. We designed molecular beacons to detect a point mutation in the methylenetetrahydrofolate reductase (MTHFR) gene, a mutation that has been related to an increased risk for cardiovascular disease and neural tube defects. The application of molecular beacons enables fast, semi- automated, accurate mutation detection. Moreover, the procedure is performed in a closed tube system, thereby avoiding carryover contamination. We believe these probes will find their way into nucleic acid research and diagnostics.