Pisatin metabolism in pea ( Pisum sativum L.) cell suspension cultures

ABSTRACT: Cell suspension cultures were established from germinating pea (Pisum sativum L.) seeds. This cell culture, which accumulated pisatin, consisted mostly of single cells containing a few cell aggregates. The cells responded to treatment with a yeast glucan preparation with transient accumulation of pisatin in both cells and culture media. Addition of pisatin to cell cultures resulted in increased synthesis of pisatin. Phenylalanine ammonia-lyase, chalcone synthase and isoflavone reductase activities were present in untreated cells. Upon treatment with an elicitor preparation the activities of the first two enzymes showed a rapid, transient increase up to 20 hours after treatment. Isoflavone reductase showed a major and minor peak at 16 and 36 h, respectively, after elicitor treatment. The time course of the enzyme activity and pisatin accumulation is consistent with an elicitor-mediated respons

Development of a competitive liposome-based lateral flow assay for the rapid detection of the allergenic peanut protein Ara h1

A competitive lateral flow assay for detecting the major peanut allergen, Ara h1, has been developed. The detector reagents are Ara h1-tagged liposomes, and the capture reagents are anti-Ara h1 polyclonal antibodies. Two types of rabbit polyclonal antibodies were raised either against the entire Ara h1 molecules (anti-Ara h1 Ab) or against an immunodominant epitope on Ara h1 (anti-peptide Ab). All of them reacted specifically with Ara h1 in Western Blot against crude peanut proteins. Moreover, the anti-Ara h1 Ab was chosen for this assay development because of its highest immunoactivity to Ara h1-tagged liposomes in the lateral flow assay. The calculated limit of detection (LOD) of this assay is 0.45μgmL−1 of Ara h1 with a dynamic range between 0.1 and 10μgmL−1 of Ara h1 in buffer. Additionally, the visually determined detection range is from 1 to 10μgmL−1 of Ara h1 in buffer. Results using this assay can be obtained within 30min without the need of sophisticated equipment or techniques; therefore, this lateral flow assay has the potential to be a cost-effective, fast, simple, and sensitive method for on-site screening of peanut allergen

A novel extraction method for peanut allergenic proteins in chocolate and their detection by a liposome-based lateral flow assay

In this study, conditions for extracting the major peanut allergen (Ara h1) from chocolate were optimized, and the extracted samples were analyzed by a lateral flow assay (LFA) using liposomal nanovesicles. The optimal conditions using peanut-spiked chocolate were found to be extraction with a mixture of phosphate buffered saline and hexane for 30min at 35°C. After centrifugation, the buffer portion was treated with insoluble poly(vinylpolypyrrolidone) to remove phenolic compounds, and then analyzed by the LFA. The entire analysis, including sample preparation and LFA, could be easily completed within 2h, and the detection limit was 158μg of peanuts/g of chocolat

Sensory and Physicochemical Quality, Residual Fungicide Levels and Microbial Load in ‘Florida Radiance’ Strawberries from Different Disease Control Treatments Exposed to Simulated Supply Chain Conditions

Strawberries are greatly appreciated for their flavor and health-promoting properties. However, current agricultural and postharvest handling practices may result in decreased fruit quality. The objective of this work was to determine the effect of conventional or reduced fungicide applications on the quality of ‘Florida Radiance’ strawberries exposed to supply chain conditions. Strawberries held under steady temperature had better sensory and physicochemical quality than fruit exposed to supply chain conditions, regardless of the disease control treatment. Strawberries from the reduced fungicide treatment were firmer, lost less moisture, had higher sugar and higher or similar bioactive contents than fruit from the conventional treatment. Sensory scores were better for reduced fungicide fruit held under steady temperature conditions than other treatments at the consumer level. Microbial load increased during the supply chain but results strongly suggest that washing the fruit significantly reduces the microbial load and residual fungicide levels (fludioxonil, cyprodinil, pyraclostrobin, and captan) on the fruit. Overall, the use of reduced fungicide applications to control strawberry disease constitutes a promising alternative to conventional practices. It will help reduce costs by reducing labor and the amount of fungicides used while maintaining overall strawberry quality. Moreover, avoiding abusive and fluctuating temperature conditions during the supply chain will extend shelf-life and reduce strawberry waste