Isoelectrofocusing of non-carboxymethylated fraction I protein from green callus

Regeneration of intergeneric somatic hybrid plants between Lycopersicon esculentum and Solanum muricatum

Mesophyll protoplasts of tomato (Lycopersicon esculentum) and pepino (Solanum muricatum) were fused by using an electrofusion method and cultured in modified MS medium supplemented with naphthaleneacetic acid and kinetin, in which only pepino and somatic hybrid protoplasts could divide. Somatic hybrid plants showing intermediate characteristics in morphology were regenerated from the calli exhibiting vigorous growth in contrast with those of pepino. The hybrid nature of these plants was confirmed by cytological observation and biochemical analyses of phosphoglucomutase isozymes and the fraction-1-protein. The regenerated somatic hybrids grew to flowering stage and set fruits.

Genetic analyses of Oryza species by molecular markers for chloroplast genomes

Relationships in a wide range of Oryza species (13 species) were analyzed using the large subunits (LS) of Fraction I protein (Rubisco) and the Bam HI restriction patterns of chloroplast DNA (ctDNA) as molecular markers. Four types of LS were detected by isoelectrofocusing with and without S-carboxymethylation. The close relation between AA and CCDD genome species was suggested by analyses of LS and ctDNA. Intraspecific variation in O. latifolia was detected at the levels of both LS and ctDNA. The LS of the BB, BBCC, and CC genomes and FF (O. brachyantha) were not distinguishable, although the native Rubisco of the latter was slightly different from those of the first three. It was also shown that O. australiensis, the only EE genome species, might have evolved differently than the other Oryza species.

Increasing the variability of Lycopersicon peruvianum Mill. by protoplast fusion with Petunia hybrida L

Somatic hybridization of Lycopersicon peruvianum and Petunia hybrida was carried out to transfer cytoplasmic male sterility from Petunia to Lycopersicon. Cytological, morphological and biochemical analyses were performed to characterize the regenerated plants. Two regenerated plants, R3 and R6, were male sterile. R3 possessed chromosomes morphologically similar to those of both parental types. Leaf morphologies of these two plants and a third plant, R7, were intermediate between the two parents. The stability of RUBPCase was verified during parental plant development and after in vitro culture. Plant R7 presented a new form of the large subunit of RUBPCase.

Analysis of catalytic subunit microheterogeneity in ribulosebisphosphate carboxylase/oxygenase from Nicotiana tabacum

Urea isoelectric focusing of dissociated, carboxymethylated Nicotiana tabacum ribulose-1,5-bisphosphate carboxylase/oxygenase reveals catalytic subunit microheterogeneity. Aggregated or nonaggregated sucrose gradient-purified preparations and the crystalline protein displayed essentially identical large subunit multiple polypeptide patterns. Various pretreatments which fully dissociate the holoenzyme did not alter catalytic subunit microheterogeneity. Direct comparison of the carboxymethylated and noncarboxymethylated crystalline and sucrose gradient-purified proteins demonstrated that the large subunit multiple polypeptide pattern was not an artifact of carboxymethylation. The inclusion of the seryl protease inhibitor phenylmethylsulfonyl fluoride during purification of the holoenzyme did not affect the large subunit multiplicity. However, the addition of leupeptin, a potent thiol proteinase inhibitor, to all solutions during purification of the native protein markedly reduced large subunit polypeptide L3 and increased the staining of polypeptide L2, suggesting that L3 is a leupeptin-sensitive proteinase degradation product of L2. Polypeptide L1 also appeared to be a purification-related artifact, but derived from a modification of L2 other than that which yielded L3. We conclude that polypeptide L2 is the single, native isoelectric form of the catalytic subunit of tobacco ribulosebisphosphate carboxylase/oxygenase.