The location of nitrite reductase and other enzymes related to amino acid biosynthesis in the plastids of root and leaves

RESP-708

Plant biotechnology: aspects of its application in industry

Plant biotechnology can serve industrial concerns in two ways; it can lead to new products and to new ways of producing an existing product (i.e. ‘processes'). The technology can be used in any business involved in using or selling plant products. In the agricultural input business molecular genetics is having most effect on the introduction of new variation into crop plants. The first products are likely to involve the introduction of insect and disease resistance and herbicide tolerance; some genes transferred will change product quality. Future applications will involve the control of more complex traits. Biotechnology will also enhance plant breeding via improved technologies (e.g. RFLPs and tissue culture); also the production of hybrids is likely to be enhanced and extended. Early products will also include the production of rDNA microbial products for control of pests and diseases. Of considerable concern to businesses is whether or not they can make sufficient financial return on plant biotechnology. The reasons behind this concern are the time it takes to introduce a product to the market; the expenditure on meeting regulatory requirements; the overall level of public acceptance of the products and the level of return from the farmer. To ensure a fair return on investment there also needs to be a secure structure of intellectual property protection (patents, plant breeders rights, etc.). Continued success in the application of plant science to agricultural improvement depends on a proper economic environment as well as the advancement of the scienc

Evaluation of techniques for extraction of hordein and glutelin from barley seed and a comparison of protein composition of Bomi and RisØ 1508

Whole seed of barley (cv. Julia) was ground, and the meal extracted to remove lipids, non-protein nitrogen compounds, albumins, and globulins. Four procedures for extracting hordein and glutelin from this meal were then compared. The composition of the isolated fractions was monitored by amino acid analysis and SDS polyacrylamide gel electrophoresis. More hordein was extracted by 55% (v/v) propan-2-ol containing 2% (v/v) 2-mercaptoethanol at 60 °C than at 20 °C or by sequential extraction with 55% propan-2-ol alone followed by 55% propan-2-ol plus 0.6% 2-mercaptoethanol. After hordein extraction glutelins were successfully extracted from the residual meal by reduction and alkylation in buffer containing 8 M urea, and were precipitated by dialysis against water. Small amounts of hordein were recovered from the alkylated glutelin by washing with hot 70% (v/v) ethanol plus 0.7% (v/v) acetic acid. The acid alcohol-insoluble glutelin was free from hordein polypeptides. Glutelins were also extracted sequentially using borate buffer at pH 10 with 0.6% mercaptoethanol followed by the same buffer with 1% SDS. Two procedures were used to compare the hordein and glutelin composition of endosperms of high lysine (RisØ 1508) and normal (Bomi, Julia) barley varieties. The hordein extracted at 60°C by 55% propan-2-ol plus 2% 2-mercaptoethanol represented almost 50% of the total N of the endosperm of Bomi and Julia, and 16% of RisØ 1508. The high lysine mutant (RisØ 1508) had more glutelin and salt-soluble nitrogen than Bomi. Electrophoretic analysis of the component polypeptides of the hordein of Bomi and RisØ 1508 showed several differences in the bands present, and in their relative proportions. In contrast the hordein-free glutelins of all three varieties appeared to have similar polypeptide compositions. Investigation of the salt-soluble fraction confirmed that the high lysine gene in RisØ 1508 results in increases in both protein and non-protein nitrogen components. The results obtained on the distribution of nitrogen between the various fractions in the seeds of Bomi and RisØ 1508 and on the amino acid analysis and polypeptide composition differ considerably from those published by other workers, in which a classical Osborne type extraction was used, and we conclude that such methods should not be used for barley

In vivo and in vitro synthesis of CM-proteins (A-hordeins) from barley (Hordeum vulgare L.)

CM-proteins from barley endosperm (CMa, CMb, CMc, CMd), which are the main components of the A-hordein fraction, are synthesized most actively 10 to 30 d after anthesis (maximum at 15–20 d). They are synthesized by membranebound polysomes as precursors of higher apparent molecular weight (13,000–21,000) than the mature proteins (12,000–16,000). The largest in vitro product (21,000) is the putative precursor of protein CMd (16,000), as it is selected with anti-CMd monospecific IgG's, and is coded by an mRNA of greater sedimentation coefficient (9 S) than those encoding the other three proteins (7.5 S). CM-proteins always appear in the soluble fraction, following different homogenization and subcellular fractionation procedures, indicating that these proteins are transferred to the soluble fraction after processing