The oil palm, an economically important tree, has been one of the world’s major sources of edible oil and a significant precursor of biodiesel fuel. Unfortunately, it now faces the threat of a devastating disease. Many researchers have identifiedGanoderma boninenseas the major pathogen that affects the oil palm tree and eventually kills it. But identification of the pathogen is just the first step. No single method has yet been able to halt the continuing spread of the disease. This paper discusses the modes of infection and transmission ofGanoderma boninenseand suggests techniques for its early detection. Additionally, the paper proposes some possible ways of controlling the disease. Such measures, if implemented, could contribute significantly to the sustainability of the palm oil industry in South East Asia.

An earlier electrochemical mechanism of DNA detection was adapted and specified for the detection of Vibrio parahaemolyticus in real samples. The reader, based on a screen printed carbon electrode, was modified with polylactide-stabilized gold nanoparticles and methylene blue was employed as the redox indicator. Detection was assessed using a microprocessor to measure current response under controlled potential. The fabricated sensor was able to specifically distinguish complementary, non-complementary and mismatched oligonucleotides. DNA was measured in the range of 2.0 × 10−8–2.0 × 10−13 M with a detection limit of 2.16 pM. The relative standard deviation for 6 replications of differential pulse voltammetry (DPV) measurement of 0.2 µM complementary DNA was 4.33%. Additionally, cross-reactivity studies against various other food-borne pathogens showed a reliably sensitive detection of the target pathogen. Successful identification of Vibrio parahaemolyticus (spiked and unspiked) in fresh cockles, combined with its simplicity and portability demonstrate the potential of the device as a practical screening tool.

A common problem in applying biosensors for the detection of genomic DNA is detecting short sequences in large amounts of long double stranded DNA. A gold electrode modified with a conductive nanocomposite, poly(3,4-ethylene-dioxythiophene), and gold nanoparticles was functionalized with 2,6-Pyridinedicarboxylic acid. Immobilization of a 20-mer DNA probe as the bioreceptor was successfully carried out via a peptide bond on the surface of the modified electrode. Two segments of 15 and 20 base probes were designed and named as Capture and Reporter probes respectively. The 20-mer Reporter probe was complementary to the bioreceptor and the 15-mer Capture probe was designed to bind on to the surface of the iron oxide magnetic nanoparticles. A 35-base Target DNA complementary to the Capture and the Reporter probes was used as Template in the ligation process, with the ligation between the Reporter and Capture probes mediated by T4 ligase. Iron oxide magnetic nanoparticles functionalized with carboxylic groups on their surface synthesized in a new method were attached to the 15-mer Capture probe. After the denaturation of the final ligation product, the separation of the attached probes was carried out using 5 G permanent magnets in a three step washing procedure in TE buffer. The hybridization of the DNA bioreceptor and the Reporter probe attached to the Capture probe-Fe3O4 was monitored via oxidation and reduction of the new redox marker (ruthenium complex) intercalated into the double helix.This technique was found to be reliably repeatable. The indirect detection of genomic DNA using this method is significantly improved and showed high efficiency in small amounts of samples with the detection limit of 5.37 × 10−14 M

Differentiating between live and dead cells is a critical step for biological researchers, clinical doctors and pharmaceutical engineers when evaluating cell viability, for determining compound cytotoxicity and in the development of effective treatments for many diseases. Usually, careful selection and combination of two different dyes are required to differentiate and image both live and dead cells. In this work, we present a new method that can differentiate, quantify and image both live and dead cells concurrently through the use of a single, cell-permeable, biochromic fluorescent dye. Two silole-based hemicyanine dyes, Silo-Cy and Silo-2Cy are designed and synthesized. These dyes exhibit green fluorescence in both live and dead cells but much stronger green and red fluorescence only from dead cells. By collecting signals from the two distinct channels, we are able to image and discriminate between live and dead cells through fluorescence microscopy and quantify the cell viability via flow cytometry.