One-step colorimetric isothermal detection of COVID-19 with AI-assisted automated result analysis: A platform model for future emerging point-of-care RNA/DNA disease diagnosis.

Colorimetric loop-mediated DNA isothermal amplification-based assays have gained momentum in the diagnosis of COVID-19 owing to their unmatched feasibility in low-resource settings. However, the vast majority of them are restricted to proprietary pH-sensitive dyes that limit downstream assay optimization or hinder efficient result interpretation. To address this problem, we developed a novel dual colorimetric RT-LAMP assay using in-house pH-dependent indicators to maximize the visual detection and assay simplicity, and further integrated it with the artificial intelligence (AI) operated tool (RT-LAMP-DETR) to enable a more precise and rapid result analysis in large scale testing. The dual assay leverages xylenol orange (XO) and a newly formulated lavender green (LG) dye for distinctive colorimetric readouts, which enhance the test accuracy when performed and analyzed simultaneously. Our RT-LAMP assay has a detection limit of 50 viral copies/reaction with the cycle threshold (Ct) value ≤ 39.7 ± 0.4 determined by the WHO-approved RT-qPCR assay. RT-LAMP-DETR exhibited a complete concordance with the results from naked-eye observation and RT-qPCR, achieving 100% sensitivity, specificity, and accuracy that altogether render it suitable for ultrasensitive point-of-care COVID-19 screening efforts. From the perspective of pandemic preparedness, our method offers a simpler, faster, and cheaper (∼$8/test) approach for COVID-19 testing and other emerging pathogens with respect to RT-qPCR.

Reverse transcription loop-mediated isothermal amplification (RT-LAMP) combined with colorimetric gold nanoparticle (AuNP) probe assay for visual detection of tilapia lake virus (TiLV) in Nile and red hybrid tilapia.

Tilapia is one of the major aquaculture species with a global economic significance. Despite a high scale of production worldwide, mortality in many tilapia cultures has recently become a problem concerned with not only intensive farming but also the prevalence of infectious pathogens. Tilapia lake virus (TiLV) has emerged as a serious single-stranded RNA disease agent that thus far has continued to cause a number of incidences across the continents. Conventional PCR-based molecular detection techniques, despite having high sensitivity for TiLV, are not best suited for the onsite identification of infected fish mainly due to their requirement of laboratory resources and extended assay turnaround time. To address this practical limitation, we have developed a novel colorimetric assay based on reverse transcription-loop-mediated isothermal amplification (RT-LAMP) and gold nanoparticle (AuNP)-labelled oligonucleotide reporter probe targeting the viral genomic segment 9 that enables the assay to be completed within an hour. This technique has been shown to be compatible with a rapid nucleic extraction method that does not demand centrifugation steps or any benchtop laboratory equipment. When validated with field-acquired tilapia samples, our RT-LAMP-AuNP assay exhibited a near-perfect agreement with the semi-nested RT-PCR assay recommended by OIE with Cohen's κ coefficient of .869, yet requiring significantly less time to perform.

An antimycobacterial cyclodepsipeptide from the entomopathogenic fungus Ophiocordyceps communis BCC 16475.

A novel cyclodepsipeptide, cordycommunin (1), and two dihydroisocoumarins (2 and 3) were isolated from the insect pathogenic fungus Ophiocordyceps communis BCC 16475. The absolute configurations of the amino acid residues of 1 were addressed by application of Marfey's method. Cordycommunin (1) showed growth inhibition of Mycobacterium tuberculosis H37Ra with an MIC value of 15 microM. This compound also exhibited weak cytotoxicity to KB cells with an IC50 of 45 microM, while it was inactive against BC, NCI-H187, and Vero cell lines at a concentration of 88 microM (50 microg/mL).

Antimycobacterial substances from Phaeosphaeria sp BCC8292.

Eleven substances including naphthalenones, naphthoquinones, unsymmetrical naphthoquinone dimers and a chlorinated diphenyl ether, three of which are new, have been isolated from the fungus Phaeosphaeria sp. The absolute stereochemistry of naphthalenones has been determined by the Mosher and exciton chirality methods. The biological activity of these compounds against Mycobacterium tuberculosis and cytotoxicity against KB, BCA, NCI-H 187 and Vero cell lines were evaluated.

Hirsutane sesquiterpenes from the fungus Lentinus connatus BCC 8996.

Two new hirsutane sesquiterpenes, connatusins A (1) and B (2), were isolated from the fungus Lentinus connatus BCC 8996. The structures, closely related to hypnophilin, were elucidated on the basis of the spectroscopic data. An X-ray analysis was performed to confirm the structure of 1. Six known compounds were also obtained. Panepoxydone (5), panepoxydione (6), and dihydrohypnophilin (8) exhibited significant antimalarial and cytotoxic activities.

Bioactive deoxypreussomerins and dimeric naphthoquinones from Diospyros ehretioides fruits: deoxypreussomerins may not be plant metabolites but may be from fungal epiphytes or endophytes.

Deoxypreussomerin derivatives, palmarumycins JC1 (1) and JC2 (2), and two dimeric naphthoquinones, isodiospyrin (3) and its new derivative isodiospyrol A (4), were isolated from dried fruits of Diospyros ehretioides. Structures of the isolated compounds were elucidated by spectroscopic analyses. Palmarumycins were not found in the extract of freshly collected fruits; however, they were present in dried fruit extract. The absence of palmarumycins in fresh fruits of D. ehretioides, together with the chemotaxonomic point of view, we proposed that palmarumycins JC1 (1) and JC2 (2) are more likely to be fungal metabolites, i.e., endophytes or epiphytes. The isolation of palmarumycins 1 and 2 from dried D. ehretioides fruits could be reproducible; both plant samples collected in the years 2002 and 2004 provided the same result, and, therefore, symbiont fungal strains should be specific to the plant host, D. ehretioides, and they can grow on the fruits during drying the sample. Palmarumycin JC1 (1) did not exhibit antimalarial, antifungal, antimycobacterial, and cytotoxic activities. Palmarumycin JC2 (2) exhibited antimalarial (IC50 4.5 microg/ml), antifungal (IC50 12.5 microg/ml), antimycobacterial (MIC 6.25 microg/ml), and cytotoxic (IC50 11.0 microg/ml for NCI-H187 cell line) activities. In our bioassay systems, isodiospyrin (3) did not exhibit antimycobacterial, antifungal, antimalarial, and cytotoxic activities. Isodiospyrol A (4) exhibited antimalarial (IC50 2.7 microg/ml) and antimycobacterial (MIC 50 microg/ml) activities, but was inactive towards Candida albicans. Compound 4 also exhibited cytotoxicity against BC cells (IC50 12.3 microg/ml), but not towards KB and Vero cell lines.