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Characterization of Pisum (pea) seed trypsin inhibitors (TI) and their corresponding cDNAs indicates that the pea TI gene family contains two genes. The existence of multiple TI isoforms can be attributed to post-translational modifications of primary gene products. Post-translational processing at the C-terminus during the desiccation stage of seed development results in the appearance of TI isoforms with increased affinity for the target enzyme, trypsin.

Only some strains of Rhizobium leguminosarum biovar viciae can efficiently nodulate varieties of peas such as cv. Afghanistan, which carry a recessive allele that blocks efficient nodulation by most western isolates of R.I. viciae. One strain (TOM) which can nodulate cv. Afghanistan peas has a gene (nodX) that is required to overcome the nodulation resistance. Strain TOM makes significantly lower amounts of lipo-oligosaccharide nodulation factors than other strains of R.I. viciae and this effect appears to be due to lower levels of nod gene induction. These nodulation factors are similar to those from other R.I. viciae strains in that they consist of an oligomer of four or five beta 1-4-linked N-acetylglucosamine residues in which the terminal non-reducing glucosamine carries an O-acetyl group and a C18:4 or C18:1 N-acyl group. However, one of the nodulation factors made by strain TOM differs from the factors made by other strains of R.I. viciae in that it carries an O-acetyl group on the C-6 of the reducing N-acetylglucosamine residue. This acetylation is NodX-dependent and the pentameric nodulation factor is acetylated on the reducing N-acetylglucosamine residue whereas the tetrameric nodulation factor is not. Although the nodL gene product is also an O-acetyl transferase (it O-acetylates the C-6 of the terminal non-reducing glucosamine), there is very little similarity between the amino acid sequences of these two acetyl transferases.

Antibodies raised against two pea (Pisum sativum L. cv. Birte) seed lipoxygenases have been used to analyze lipoxygenase heterogeneity in seeds and in other organs. At least seven different polypeptides were identified in vivo; five of these were identified as precursors synthesized in vitro. The developmental appearance of the seed polypeptides has been analyzed and 'early' and 'late' forms were identified. Limited N-terminal sequence data indicated further heterogeneity when compared with sequences predicted from cDNAs.

Streptomyces lividans DNA contains a modification which makes it susceptible to double-strand cleavage during electrophoresis in buffers contaminated with ferrous iron (which may be present in some batches of EDTA). The cleavage of the DNA is site-specific and the average fragment size resulting from limit digestion of total S. lividans DNA is about 6kb. DNA from Streptomyces coelicolor A3(2) and several other Streptomyces strains, and from E. coli, is not cleaved under the same conditions. A S. lividans mutant has been isolated which lacks the DNA modification. We suspect that many reports of "poor" preparations of S. lividans plasmids may be due to the above effect.