Aptameric Fluorescent Biosensors for Liver Cancer Diagnosis.

Liver cancer is a prevalent global health concern with a poor 5-year survival rate upon diagnosis. Current diagnostic techniques using the combination of ultrasound, CT scans, MRI, and biopsy have the limitation of detecting detectable liver cancer when the tumor has already progressed to a certain size, often leading to late-stage diagnoses and grim clinical treatment outcomes. To this end, there has been tremendous interest in developing highly sensitive and selective biosensors to analyze related cancer biomarkers in the early stage diagnosis and prescribe appropriate treatment options. Among the various approaches, aptamers are an ideal recognition element as they can specifically bind to target molecules with high affinity. Furthermore, using aptamers, in conjunction with fluorescent moieties, enables the development of highly sensitive biosensors by taking full advantage of structural and functional flexibility. This review will provide a summary and detailed discussion on recent aptamer-based fluorescence biosensors for liver cancer diagnosis. Specifically, the review focuses on two promising detection strategies: (i) Förster resonance energy transfer (FRET) and (ii) metal-enhanced fluorescence for detecting and characterizing protein and miRNA cancer biomarkers.

Identification of target genes for RNAi-mediated control of the Twospotted Spider Mite.

RNA interference (RNAi) is being developed for the management of pests that destroy crops. The twospotted Spider Mite (TSSM), Tetranychus urticae is a worldwide pest due to its unique physiological and behavioral characteristics including extraordinary ability to detoxify a wide range of pesticides and feed on many host plants. In this study, we conducted experiments to identify target genes that could be used for the development of RNAi-based methods to control TSSM. Leaf disc feeding assays revealed that knockdown in the expression genes coding for proteins involved in the biosynthesis and action of juvenile hormone (JH) and action of ecdysteroids [Methoprene-tolerant (Met), retinoid X receptor ß, farnesoic acid O-methyltransferase, and CREB-binding protein] caused 35-56% mortality. Transgenic tobacco plants expressing hairpin dsRNA targeting Met gene were generated and tested. About 48% mortality was observed in TSSM raised on transgenic tobacco plants expressing dsMet. These studies not only broaden our knowledge on understanding hormone action in TSSM but also identified target genes that could be used in RNAi-mediated control of TSSM.

Toxicity and synergic repellency of plant essential oil mixtures with vanillin against Aedes aegypti (Diptera: Culicidae).

In all triplicate tests of six plant essential oils and of vanillin mixtures, we corroborated strong insecticidal and repellent activities against adult Aedes aegypti (L.). Essential oils with potent toxic fumigant activities also exhibited repellency. Compared with N, N-diethyl-3-methylbenzamide, 5% of the essential oil concentrations of cassia, lemongrass, lemon eucalyptus, and xanthoxylum oils did not show repellent effects. However, a composition oflemongrass oil, xanthoxylum oil, and vanillin (1:3:1, vol:vol:wt) provided 270 min of complete protection time (CPT) compared with 247.5 min CPT with 15% N, N-diethyl-3-methylbenzamide. The CPT depended on concentration, presence ofvanillin, or on both factors. When we applied a mixture of lemongrass oil: xanthoxylum oil: vanillin (1:1:1, vol:vol:wt) to the Viscopearl formulation, or porous cellulose beads, it provided gradual release of volatile compounds, thus showing >90% of repellency for 2 h. The behavioral and electrophysiological approaches we drew upon in our current study demonstrated that plant essential oil mixtures combined with vanillin showed strong and durable repellency to the mosquito. We claim that such combinations of plant essential oils and vanillin found in current study propose a viable commercial product suitable for future application in protecting a person from mosquito bites.