Electrophoretic analysis of peroxidase isoenzymes and other proteins present in the culture medium of potato (Solanum tuberosum L. cv. Bintje) cells in suspension culture was carried out by isoelectric focusing and starch gel electrophoresis. The results showed that during the exponential growth phase, the number of peroxidase isoenzymes as well as their activities increased. In addition, several other proteins have increased in the culture medium.The high specific activity of medium peroxidase as compared to that of cellular peroxidase and differences in the release of various peroxidase isoenzymes suggest that the peroxidase was released by specific secretion.

No abstract

No abstract

The genetic variability of eight carrot populations representing commercially important morphological types was analyzed for seed protein polymorphism by one- and two-dimensional electrophoresis using immobilized pH gradients (IPG) in order to assess the potential of both techniques in carrot hybrid breeding as well as genetic quality testing of carrot trade seeds. The digitized silver-stained one- and two-dimensional gels of the urea/detergent-soluble seed proteins were subjected to computer analysis to estimate both the inter- and intrapopulation genetic variability. The results indicated that isoelectric focusing (IEF-IPG) of seed proteins is a powerful tool for quick screening of the genetic variability present between and within carrot populations, while two-dimensional polyacrylamide gel electrophoresis (IPG-DALT) can be employed to establish detailed genetic relationships of carrot populations selected by initial IEF-IPG screening in order to use genetic distant and homogeneous populations for successful carrot hybrid breeding. However, the applicability of IEF-IPG in genetic quality testing of carrot seeds seems to be restricted to hybrid purity testing. IPG-DALT is a far more powerful tool to profile unambiguously all carrot varieties commercially used in order to test the genetic quality of trade seeds, because this technique exhibits protein spots or spot combinations exclusively found in each of the eight varieties investigated.

Peroxidase activity and isoenzyme composition of cells and culture medium were analysed in a cell suspension culture of Haplopappus gracilis. The results revealed marked changes in the activity and isoenzyme patterns of peroxidase during the culture cycle. During the exponential growth phase the peroxidase activity of the cells increased and a considerable amount of peroxidase was released into the culture medium. Several peroxidase isoenzymes in the medium increased in activity continuously throughout the whole exponential growth phase while others decreased during the second half of this phase. The decrease of the latter was caused by diffusion of the isoenzymes back into the cell walls as well as by inhibitors. During the stationary phase of the cell cycle only small changes occurred in the peroxidase activity and isoenzyme patterns.