14 research outputs found

    Characterization of three Colletotrichum acutatum isolates from Capsicum spp.

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    Colletotrichum acutatum causes anthracnose on peppers (Capsicum spp.), resulting in severe yield losses in Taiwan. Fungal isolates Coll-153, Coll- 365 and Coll-524 collected from diseased peppers were found to differ in pathogenicity. Pathogenicity assays on various index plants revealed that Coll-524 was highly virulent and Coll-153 was moderately virulent to three commercially available pepper cultivars. Both isolates induced anthracnose lesions and produced abundant conidia. Coll-365 was only weakly virulent on pepper fruit, where it caused small lesions and hardly produced conidia on pepper fruit. However, Coll-365 was highly pathogenic to tomato fruit and mango leaves, where it caused anthracnose lesions and formed acervuli and conidia. All three isolates showed similar abilities in the attachment and germination of conidia, formation of highly branched hyphae and appressoria, penetration of cuticles, and infection of epidermal cells on chili peppers. Coll-365 accumulated less turgor pressure in appressoria but produced higher levels of cutinase and protease activity than Coll-153 and Coll-524 did. All three isolates invaded the neighbouring cells through plasmodesmata in chili peppers and showed similar pectinase or cellulase activities in culture. However, the most virulent strain Coll-524 expressed stronger laccase activity and was more resistant to capsaicin compared to Coll-153 and Coll-365. The three isolates are different in numbers and sizes of double-stranded RNAs. Depending on the cultivar genotypes, cellular resistance of chili pepper to C. acutatum might rely on the ability to restrict penetration, colonization, or conidiation of the pathogen. We conclude that the differences in pathogenicity among the three C. acutatum isolates of pepper are attributed to their ability to colonize the host plant

    A microvalve cell printing technique using riboflavin photosensitizer for selective cell patterning onto a retinal chip

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    Delivery of cells onto subretinal chips for stimulation possess a significant technical challenge. Often, such capabilities are confined by sophisticated laboratory-based commercial instrumentation, which are inherently expensive and equipped with a limited capacity. As a result, exploring new delivery techniques requires an ad hoc approach to suit the requirements of the target deposition method, material(s) and cells under investigation. For the first time, a customised 3D printer, equipped with a microvalve, developed at a low cost, and capable of high resolution placement on a retinal chip is proposed. This allowed the investigation of a pneumatically-driven and microvalve printing technique to deliver cells on a subretinal chip, thus suiting the required resolution and localization of cells. The bioink is coupled with a light-induced collagen photo-crosslinking mechanism. The collagen, mixed with the riboflavin, can be crosslinked after exposure to blue light. The cells printed on the chip remained in the collagen patterns and demonstrated good viability and growth. This technique provided a useful means of delivering cells where high precision, throughput and accuracy is required, such as onto sub-retinal chips

    Information and Control ICIC International c ⃝2012 ISSN

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    Abstract. Diabetes, which ranks 4th among the top ten causes of death in Taiwa
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