Characterization of Fusarium species section Liseola by restriction analysis of the IGS region.

Fusarium species section Liseola namely F. fujikuroi, F. proliferatum, F. andiyazi, F. verticillioides, and F. sacchari are well-known plant pathogens on rice, sugarcane and maize. In the present study, restriction analysis of the intergenic spacer regions (IGS) was used to characterize the five Fusarium species isolated from rice, sugarcane and maize collected from various locations in Peninsular Malaysia. From the analysis, and based on restriction patterns generated by the six restriction enzymes, Bsu151, BsuRI, EcoRI, Hin6I, HinfI, and MspI, 53 haplotypes were recorded among 74 isolates. HinfI showed the most variable restriction patterns (with 11 patterns), while EcoRI showed only three patterns. Although a high level of variation was observed, it was possible to characterize closely related species and isolates from different species. UPGMA cluster analysis showed that the isolates of Fusarium from the same species were grouped together regardless of the hosts. We conclude that restriction analysis of the IGS regions can be used to characterize Fusarium species section Liseola and to discriminate closely related species as well as to clarify their taxonomic position.

Ion exchange immobilization of changed beta-galactosidase fusions for lactose hydrolysis.

The use of charged peptides fused to enzymes for immobilization onto ion-exchange membranes was explored for the enzyme x-galactosidase. The additional charged peptides, containing 1, 5, 11, and 16 aspartates, fused to x-galactosidase, for the most part did not interfere with the kinetic behavior for lactose hydrolysis. There was a 2-fold decline in V(m) for the 16-aspartate fusion, but the others were quite similar to the wild type enzyme (BGWT). BGWT and the fusions all retained approximately 50% of their activities when adsorbed onto ion-exchange membranes. In contrast to BGWT, the enhanced binding strength of the 11 aspartate fusion provided the ability to hydrolyze whey permeate at 0.3 M ionic strength without enzyme leakage, and to immobilize the enzyme directly from diluted cell extract with 83% purity.

Charged fusions for selective recovery of beta-galactosidase from cell extract using hollow fiber ion-exchange membrane adsorption.

We explored the use of charged fusions for selective recovery of beta-galactosidase from cell extract using a low-cost, easily scaled, fast, charge-based separation technique-ion exchange on hollow fiber ion-exchange membranes (HFIEMs). The additional charges carried by a series of anionic fusion tails allowed selective binding and release of beta-galactosidase from Escherichia coli cell extract using the HFIEM cartridge. The purification factors increased with fusion length. The beta-galactosidase was recovered in active form. For the longest fusion studied, more than sixfold enrichment in specific activity was attained. The specific activity of the recovered fraction is comparable with that of commercial wild-type beta-galactosidase and affinity-purified fusion protein.