A mutant ß-glucosidase increases the rate of the cellulose enzymatic hydrolysis.

The enzymatic hydrolysis of cellulose and lignocellulosic materials is marked by a rate decrease along the reaction time. Cellobiohydrolase slow dissociation from the substrate and its inhibition by the cellobiose produced are relevant factors associated to the rate decrease. In that sense, addition of ß-glucosidases to the enzyme cocktails employed in cellulose enzymatic hydrolysis not only produces glucose as final product but also reduces the cellobiohydrolase inhibition by cellobiose. The digestive ß-glucosidase GH1 from the fall armyworm Spodoptera frugiperda, hereafter called Sfßgly, containing the mutation L428V showed an increased kcat for cellobiose hydrolysis. In comparison to assays conducted with the wild-type Sfßgly and cellobiohydrolase TrCel7A, the presence of the mutant L428V increased in 5 fold the initial rate of crystalline cellulose hydrolysis and reduced to one quarter the time needed to TrCel7A produce the maximum glucose yield. As our results show that mutant L428V complement the action of TrCel7A, the introduction of the equivalent replacement in ß-glucosidases is a promising strategy to reduce costs in the enzymatic hydrolysis of lignocellulosic materials.

Association between Parkinson's disease and glucocerebrosidase mutations in Brazil.

OBJECTIVE: To evaluate the association between parkinsonism and mutations in the glucocerebrosidase gene (GBA) in Brazilian patients. METHODS: We searched for three GBA common mutations (N370S, L444P and G377S) in 65 Brazilian patients affected by PD with disease onset before the age of 55 and compared the results to 267 age- and sex-matched controls. RESULTS: GBA mutations were detected at a significantly higher frequency among Parkinson's disease patients (2/65=3%), when compared to the control group (0/267): P=0.0379. CONCLUSION: These results provide further evidence for GBA mutations being a possible hereditary risk factor for PD.

The frequency of Tay-Sachs disease causing mutations in the Brazilian Jewish population justifies a carrier screening program

CONTEXT: Tay-Sachs disease is an autosomal recessive disease characterized by progressive neurologic degeneration, fatal in early childhood. In the Ashkenazi Jewish population the disease incidence is about 1 in every 3,500 newborns and the carrier frequency is 1 in every 29 individuals. Carrier screening programs for Tay-Sachs disease have reduced disease incidence by 90 percent in high-risk populations in several countries. The Brazilian Jewish population is estimated at 90,000 individuals. Currently, there is no screening program for Tay-Sachs disease in this population. OBJECTIVE: To evaluate the importance of a Tay-Sachs disease carrier screening program in the Brazilian Jewish population by determining the frequency of heterozygotes and the acceptance of the program by the community. SETTING: Laboratory of Molecular Genetics - Institute of Biosciences - Universidade de Säo Paulo. PARTICIPANTS: 581 senior students from selected Jewish high schools. PROCEDURE: Molecular analysis of Tay-Sachs disease causing mutations by PCR amplification of genomic DNA, followed by restriction enzyme digestion. RESULTS: Among 581 students that attended educational classes, 404 (70 percent) elected to be tested for Tay-Sachs disease mutations. Of these, approximately 65 percent were of Ashkenazi Jewish origin. Eight carriers were detected corresponding to a carrier frequency of 1 in every 33 individuals in the Ashkenazi Jewish fraction of the sample. CONCLUSION: The frequency of Tay-Sachs disease carriers among the Ashkenazi Jewish population of Brazil is similar to that of other countries where carrier screening programs have led to a significant decrease in disease incidence. Therefore, it is justifiable to implement a Tay-Sachs disease carrier screening program for the Brazilian Jewish population