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Okayama-shi, Japan

Takahashi N.,Ehime University | Okamura K.-I.,NISSHOKU Group Inc. | Matsuda Y.,NISSHOKU Group Inc. | Igari K.,NISSHOKU Group Inc. | And 8 more authors.
Environmental Control in Biology | Year: 2012

The transgenic lettuce expressing double repeated Stx2eB (2 × Stx2eB) is considered to be an edible vaccine candidate against swine edema disease. For the efficient vaccine protein production in transgenic lettuce grown in a plant factory, the effects of air flow on vaccine protein production in transgenic lettuce were investigated. Plants were grown hydroponically in a closed-type plant factory for 21 days with four airflow patterns: 1) air flow from the side to leaves at 2.0 m s -1; 2) air flow from the top to the inner developing leaves with flexible transparent tubing at 1.0 m s -1; 3) air flow from the bottom to leaves with transparent tubing at 1.0 m s -1; and 4) no air flow. Our results showed that the total leaf number in air flow from the top and the bottom to leaves was significantly increased compared with that in no air flow. While lettuce growth with inner air flow and bottom air flow was enhanced, tipburn at the developing leaves were eliminated by air flow. 2 × Stx2eB per plant in bottom air flow to leaves was the highest of the four air flow patterns. These results suggest that bottom air flow to the leaves can enhance vaccine protein productivity in transgenic lettuce. Source


Okamura K.-I.,NISSHOKU Group Inc. | Okamura K.-I.,Osaka Prefecture University | Matsuda Y.,NISSHOKU Group Inc. | Igari K.,NISSHOKU Group Inc. | And 7 more authors.
Environmental Control in Biology | Year: 2013

Production technologies using closed-type plant production systems have been studied to assess their suitability for stable and uniform expression of biopharmaceutical materials in transgenic plants. We have developed a production system for a veterinary vaccine candidate against swine edema disease, using transgenic plants. In this paper, we report the combined effects of plant cultivation density and light intensity on the production levels of a vaccine candidate, the double repeated B subunit of Shiga toxin 2e (2-Stx2eB), in transgenic lettuce cultivated in a closed-type plant factory. Leaf drymatter yield and total soluble protein (TSP) yield increased at higher plant cultivation densities, but in contrast, the 2- Stx2eB concentration in the plants tended to decrease with an increase in plant cultivation density, so that the 2-Stx2eB yield per unit area at lower plant cultivation density (44.4 plants m-2) was similar to or even higher than that obtained at the highest plant density (222.2 plants m-2). In addition, at the cultivation density (44.4 plants m-2), a photosynthesis photon flux density (PPFD) 200 (200-50 -mol m-2 s-1) was optimal in terms of maximizing the 2-Stx2eB yield and minimizing the electrical consumption of lighting. These results show that an optimal combination of plant cultivation density and light intensity is important in improving the productivity of recombinant protein expression systems in transgenic lettuce leaves when grown in a plant factory. Source


Okamura K.-I.,NISSHOKU Group Inc. | Matsuda Y.,NISSHOKU Group Inc. | Igari K.,NISSHOKU Group Inc. | Fukuda H.,Osaka Prefecture University | Murase H.,Osaka Prefecture University
Environmental Control in Biology | Year: 2014

The amount of growth and the vaccine productivity of vaccine-producing lettuce with different cultivation periods were examined in order to determine the optimal harvesting time of transgenic lettuce cultivated in a closed plant factory. Lettuce was planted in a hydroponic system and harvested at 20, 30, 40, and 50 d, and the concentrations of the total soluble protein (TSP) and the double repeated B subunit of Shiga toxin 2e (2×Stx2eB) were measured. The dry-matter weight of leaves per plant increased in a linear fashion until 50 d. Although the TSP concentration decreased continually from day 20 to 50 and 2×Stx2eB concentration decreased from day 40 to 50, the yield per plant of both TSP and 2×Stx2eB increased exponentially until day 50. According to the calculation based on these results, the optimal harvesting time to maximize the annual production of 2×Stx2eB was revealed to be 30 d. Since the optimal 30-d harvesting time is the same to the general harvesting time for commercial lettuce production in a closed plant factory, the capability to utilize the existing closed plant factory lettuce production system could be a big advantage for vaccine-producing lettuce in terms of the cost performance. Source

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