Publications by authors named "Oraprapai Gajanandana"

The Strep Easy Kit, a bio-enrichment dual ICG-strip test, is a diagnostic tool designed for the detection of Streptococcus agalactiae, an important pathogenic bacterium in tilapia farming. The kit can simultaneously identify two different serotypes of S. agalactiae, serotype Ia and serotype III.

View Article and Find Full Text PDF

Equipment-free colorimetric-based lateral flow immunoassay (LFIA) is the most convenient and popular tool for various applications, including diagnostic tools requiring high sensitivity for the detection of pathogens. Thus, improvements and developments of LFIA are constantly being reported. Herein, we enriched the sensitivity of LFIA using the gold enhancement principle, emphasizing needlessly complicated apparatus, only one step for the strip test operation, and typical time incubation (15 min) process.

View Article and Find Full Text PDF

Background: Cassava mosaic disease (CMD) is one of the most devastating viral diseases for cassava production in Africa and Asia. Accurate yet affordable diagnostics are one of the fundamental tools supporting successful CMD management, especially in developing countries. This study aimed to develop an antibody-based immunoassay for the detection of Sri Lankan cassava mosaic virus (SLCMV), the only cassava mosaic begomovirus currently causing CMD outbreaks in Southeast Asia (SEA).

View Article and Find Full Text PDF

Acidovorax citrulli, a seedborne bacterium and quarantine pest, causes the devastating bacterial fruit blotch disease in cucurbit plants. Immunological assays such as ELISA are widely used in routine field inspections for this bacterium. However, to the best of our knowledge, none of the currently available monoclonal antibodies (MAbs) can detect all common A.

View Article and Find Full Text PDF

Recent developments in smartphone-based strip readers have further improved the performances of lateral flow test kits. Most smartphone cameras encode an unaltered and nonlinear power-law transfer function that maps the light intensity to a pixel value; this poses some limitations for camera-based strip readers. For faint-color test lines which are almost as white such as with nitrocellulose pads, the slope of the transfer function is low.

View Article and Find Full Text PDF

Background: Tomato yellow leaf curl Thailand virus, TYLCTHV, is a begomovirus that causes severe losses of tomato crops in Thailand as well as several countries in Southeast and East Asia. The development of monoclonal antibodies (MAbs) and serological methods for detecting TYLCTHV is essential for epidemiological studies and screening for virus-resistant cultivars.

Methods: The recombinant coat protein (CP) of TYLCTHV was expressed in Escherichia coli and used to generate MAbs against TYLCTHV through hybridoma technology.

View Article and Find Full Text PDF

To employ a microsphere immunoassay (MIA) to simultaneously detect multiple plant pathogens (potyviruses, Watermelon silver mottle virus, Melon yellow spot virus, and Acidovorax avenae subsp. citrulli) in actual plant samples, several factors need to be optimized and rigorously validated. Here, a simple extraction method using a single extraction buffer was successfully selected to detect the four pathogens in various cucurbit samples (cucumber, cantaloupe, melon, and watermelon).

View Article and Find Full Text PDF

A protocol for identifying tospovirus and thrips species in an individual thrips sample was successfully developed. First, an individual thrips was soaked in an RNA stabilization solution to preserve protein and nucleic acids and ground in a carbonate buffer containing 0.2% sodium diethyldithiocarbamate.

View Article and Find Full Text PDF

The global seed market is considered to be an important industry with a total value of $10,543 million US dollars in 2012. Because plant pathogens such as bacteria and viruses cause a significant economic loss to both producers and exporters, the seed export industry urgently requires rapid, sensitive, and inexpensive testing for the pathogens to prevent disease spreading worldwide. This study developed an antibody array in a multiwell plate format to simultaneously detect four crucial plant pathogens, namely, a bacterial fruit blotch bacterium Acidovorax avenae subsp.

View Article and Find Full Text PDF

In this study, a multiplex RT-PCR-ELISA was developed to detect and differentiate four tospovirus species found in Thailand, namely Capsicum chlorosis virus (CaCV), Melon yellow spot virus (MYSV), Tomato necrotic ringspot virus (TNRV), and Watermelon silver mottle virus (WSMoV). In this system, nucleocapsid (N) gene fragments of four tospoviruses were simultaneously amplified and labeled with digoxigenin (DIG) in a single RT-PCR reaction using a pair of degenerate primers binding to the same conserved regions in all four tospovirus N genes. The DIG-labeled amplicons were distinguished into species by four parallel hybridizations to species-specific biotinylated probes in streptavidin-coated microtiter wells followed by ELISA detection using a peroxidase-conjugated anti-DIG antibody.

View Article and Find Full Text PDF

Plant pathogens are a serious problem for seed export, plant disease control and plant quarantine. Rapid and accurate screening tests are urgently required to protect and prevent plant diseases spreading worldwide. A novel multiplex detection method was developed based on microsphere immunoassays to simultaneously detect four important plant pathogens: a fruit blotch bacterium Acidovorax avenae subsp.

View Article and Find Full Text PDF

Antibodies are very important materials for diagnostics. A rapid and simple hybridoma screening method will help in delivering specific monoclonal antibodies. In this study, we systematically developed the first antibody array to screen for bacteria-specific monoclonal antibodies using Listeria monocytogenes as a bacteria model.

View Article and Find Full Text PDF

A novel monoclonal antibody (MAb) specific to the seedborne bacterium Acidovorax citrulli was produced. MAb 11E5 reacted specifically with 19 strains of A. citrulli but not with three closely related bacteria in the family Comamonadaceae (i.

View Article and Find Full Text PDF

A new tospovirus isolated from naturally infected tomato plants grown in Nakhon Pathom province (Thailand) was characterized. Infected plants showed symptoms consisting of necrotic spots, necrotic ringspots and stem necrosis. This virus was detected using general antibodies that could recognize watermelon silver mottle virus (WSMoV), capsicum chlorosis virus (CaCV) and melon yellow spot virus (MYSV).

View Article and Find Full Text PDF

An immunosensor based on surface plasmon resonance imaging (SPR imaging) using a specific monoclonal antibody 11E5 (MAb 11E5) was developed for the detection of the seed-borne bacterium Acidovorax avenae subsp. citrulli (Aac), which causes fruit blotch in watermelons and cantaloupes, and compared to the conventional ELISA technique. The 1:40 mixed self-assembled monolayer (mixed SAM) surface was used for the immobilized MAb 11E5 on sensor surface for the detection of Aac.

View Article and Find Full Text PDF

Pathogenic bacterial contaminations present serious problems for food industry and public health. Rapid, accurate and affordable assays are needed. In this study, antibody arrays to simultaneously detect two foodborne pathogenic bacteria (Escherichia coli O157:H7 and Salmonella spp.

View Article and Find Full Text PDF

Twenty-eight isolates of tospoviruses associated with tomato, pepper, cucurbits, peanut, and Physalis plants collected from fields in different regions of Thailand were characterized. On the basis of N gene and protein sequence relationships, three tospoviruses were identified, namely Watermelon silver mottle virus (WSMoV), Capsicum chlorosis virus (CaCV), and Melon yellow spot virus (MYSV). CLUSTAL analysis of selected N protein sequences showed different isolates of CaCV in three distinct clades.

View Article and Find Full Text PDF