The Sprout

GibberelHc acid is also used successfliUy in rice culture to promote seed germination and the growth of semidwarf varieties. The treated seed can be planted deeper than normal. In addition, the sprouting seedlings are much taller than the untreated ones they compete weU against weeds. The material is sold under the trade name Release. 

Radioisotopes have important commercial applications. For example, americium-241 is used in smoke detectors. Its role is to ionize any smoke particles, which then allow a current to flow and set off the alarm. Exposure to radiation is also used to sterilize food and inhibit the sprouting of potatoes. Radioisotopes that give off a lot of energy as heat are also used to provide power in remote locations, where refueling of generators is not possible. Unmanned spacecraft, such as Voyager 2, are powered by radiation from plutonium. 

The amino acid composition of storage proteins differs from that of the complete sprout [12, 13]. At least in the case of oilseed rape, alfalfa (Medicago sativa L.) and Camelina sativa, amino acids in the sprout are used mainly, either directly or indirectly, for the synthesis of the Rubisco proteins. Computer analysis shows that the amino acid composition of cruciferin and napin is completely different to the amino acid composition of Rubisco. This indicates that amino acids released from the seed storage proteins must be converted into other amino acids prior to Rubisco synthesis. 

Chloroplast protein synthesis is controlled largely at the post-transcriptional level [20,21] and can be repressed by the inclusion of antibiotics such as streptomycin in the sprouting medium. Streptomycin binds to the 16S rRNA and causes the ribosome to misread the mRNA sequence, producing incorrect and non-functional proteins [22]. 

Fig. 3.4 A. Laboratory scale 10-L sprouting equipment. The apparatus is made from glass. Oilseed rape sprouts have been grown for three days under continuous aeration. The sprouting medium is tap water. B. A schematic drawing of the major parts of the apparatus.

Other systems, in which the sprouts are grown in a tank and submerged in water at intervals of several hours, are used often for commercial production of sprouts for food. Light and aeration conditions are not fully uniform in such systems, because inside the sprout mass less light is available. The use of light-inducible promoters clearly demands another kind of sprouting system. 

In our case, sprouting in an effectively aerated water medium was selected as the sprouting method of choice. In our system the sprouts are moving and circulating vigorously with the water flow. Effective aeration is necessary seeds submerged in water without aeration do not sprout and eventually die. Normal tap water or reverse osmosis purified water (RO-water) can be used. 

Microbial contamination, especially by salmonellas, is a risk when sprouts are produced commercially for human consumption. For recombinant protein production, seeds can be washed with water and surface-sterilized using hypochlorite solution. Sprouts can also be surface-sterilized during sprouting, by the addition of mild hypochlorite solution directly into the growth medium. Eventually, the hypochlorite is diluted out with pure water or growth medium. In our experiment on plate count agar [28], the sprouts showed no bacterial growth after sterilization with 1% sodium hypochlorite. 

Fig. 3.6 Human serum albumin (HSA) was produced during the sprouting of transgenic rape-seeds. A light-inducible Rubisco promoter was used to control transgene expression. The highest yield was obtained with light induction after three days of continuous darkness. Sprouting was carried out in an airlift fermentor at room temperature. The sprouting medium was water.

B.) The yield of recombinant HSA, as determined using an enzyme-linked immunosorbent assay (ELISA). The sprouts were germinated in an airlift bioreactor tank for 175 hours in the presence or absence of 20 mM KN03. Recombinant HSA was expressed under the control of the Rbc56 promoter isolated in our laboratory. 

According to FAO statistics, the average field harvest of oilseed rape in Europe is 2500 kg ha-1 [8] and based on our own experiments, 3000 kg ha-1 yields can be obtained in the greenhouse. This translates into an annual harvest potential of 9000 kg ha-1, based on the fact that three harvests each of 3000 kg ha 1can be obtained in a year. The desired protein is produced predominantly in the sprout. The developing seeds do not accumulate recombinant protein. 

Currently, we can produce 1.5 g of GUS protein and 0.5 g of HSA per kg of seeds. These levels correspond to 13.5kg and 4.5 kg production yields per year, respectively. Expression levels are indicated as a weight per weight of starting material (dry seeds) because the sprout fresh weight and total soluble protein content varies depending on cultivation time and conditions. 

Red Phosphorus smoke mix production. Evaluation of the Sprout Waldron 35 cubic foot Jet Airmix unit for production of Red Phosphorus (RP) M8E1 Smoke Mixtures was conducted (12). Results indicated the mix was stabile and not easily initiated by heat, but sensitive to friction and snark stimuli. The burning time was slow with dense smoke emission. 

Seed potatoes usually appear in nurseries, or are shipped by mailorder suppliers, in late winter to early spring, in order that they may be "chitted" for a few weeks before planting out. Lay out the tubers in shallow trays—egg cartons near right) are ideal. Place the end with the most "eyes" (dormant buds) uppermost. Put them in a light, warm place until they sprout. Once frost has become rare and the soil has warmed up, plant them out far right) with the sprouted end uppermost. 

Kramer, M. E., and Lim, D. V. (2004). A rapid and automated fiber optic-based biosensor assay for the detection of Salmonella in spent irrigation water used in the sprouting of sprout seeds. /. Food Prot. 67,46-52. 

An important factor determining the efficacy of radiation treatment of tubers and bulbs is the time delay between harvest and irradiation. The sprout inhibition is most pronounced if the irradiation of tubers and bulbs is applied shortly after harvest, when they are still in their dormancy stage. However, the dormancy period may vary among cultivars and cropping season, and is also dependent on the postharvest storage temperature. 

The sprout inhibition was reversible, thus it can be used for seed tuber storage (Vokou et al., 1993). 

Burton, W. G. (1958). The effect of the eoneentrations of carbon dioxide and oxygen in the storage atmosphere upon the sprouting of potatoes at 10°C. European Potato Journal, 1(2), 41-51. 

Gubb, L, Moorby, J. (1995). The effects of controlled atmosphere storage on the sprouting of potato tubers. 

---