Evaluation of a Loop-Mediated Isothermal Amplification Technique for the Rapid Visual Detection of Hepatozoon canis Infection

Colorimetric strategies applicable for loop-mediated isothermal amplification

In recent years, loop-mediated isothermal amplification (LAMP) has gained popularity for detecting various pathogen-specific genes due to its superior sensitivity and specificity compared to conventional polymerase chain reaction (PCR). The simplicity and flexibility of naked-eye detection of the amplicon make LAMP an ideal rapid and straightforward diagnostic tool, especially in resource-limited laboratories. Colorimetric detection is one of the simplest and most straightforward among all detection methods. This review will explore various colorimetric dyes used in LAMP techniques, examining their reaction mechanisms, advantages, limitations and latest applications.

Distinction of Male and Female Trees of Ginkgo biloba Using LAMP

Ginkgo biloba is utilized as food, medicine, wood, and street trees among other things. The objective of this study was to develop a loop-mediated isothermal amplification (LAMP) assay for gender distinction of G. biloba. Male-specific SCAR gene can be utilized to identify G. biloba gender using LAMP. The optimized LAMP conditions, temperature 60 °C, 2-mM MgSO4, and [F3/B3]:[FIP/BIP] primer ratio of 1:4 were selected as final conditions. The G. biloba SCAR LAMP displayed a sensitivity of 10 ng when amplified by concentration under the optimum conditions. Additionally, it demonstrated a particular response in male with SYBR Green I in LAMP analysis that can be a more powerful tool for field and scale-up applications. Our work represents a first attempt to identify G. biloba gender using LAMP and offers an efficient and reliable tool for roadside landscaping.

Development of a loop-mediated isothermal amplification assay based on RoTat1.2 gene for detection of Trypanosoma evansi in domesticated animals

The early containment of trypanosomosis depends on early, sensitive, and accurate diagnosis in endemic areas with low-intensity infections. The study was planned to develop a simple read out loop-mediated isothermal amplification (LAMP) assay targeting a partial RoTat1.2 VSG gene of Trypanosoma evansi with naked eye visualization of LAMP products by adding SYBR® Green I dye. The visual results were further confirmed with those of agarose gel electrophoresis, restriction enzyme digestion of LAMP products with AluI, and sequencing of the PCR products using LAMP outer primers. The LAMP primers did not show cross reactivity and non-specific reactions with regional common hemoparasitic DNA revealing high specificity of the assay. The threshold sensitivity level of the LAMP assay was determined to be 0.003 fg compared to 0.03 fg RoTat1.2 amplified DNA fragments of T. evansi by PCR assay. Moreover, assessment of 500 blood samples collected from unhealthy domestic animals in field suspected for various hemoparasitic infections was carried out for the presence of T. evansi by microscopy, RoTat1.2 VSG PCR, and LAMP assay. LAMP could detect T. evansi in 36 samples, while PCR and microscopy could detect 33 and 12 samples, respectively. All the samples positive by microscopy and PCR were also confirmed positive by the LAMP assay. The current LAMP assay has appealing point of care characteristics to visually monitor the results, lessen the need of post DNA amplification procedure, and enable this method to be applied as a rapid and sensitive molecular diagnostic tool in under resourced laboratories and field setup.