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The catalytic capacity of several excreted pectinolytic enzymes obtained from various yeast strains was examined using in vivo and biochemical techniques. Of the 33 yeast strains studied, 30 were isolated from champagne wine during alcoholic fermentation. Only one yeast strain was found to excrete pectinolytic enzymes and was identified as Saccharomyces cerevisiae and designated SCPP. Pulsed-field gel electrophoresis and the polymerase chain reaction technique were used to characterize further this specific strain. Three types of pectinolytic enzymes were found to be excreted by SCPP: polygalacturonase, pectin-lyase and pectin-esterase. These enzymes allow pectin hydrolysis during cell growth.

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Abstract. The amino acid sequences of 22 ␣-amylases from family 13 of glycosyl hydrolases were analyzed with the aim of revealing the evolutionary relationships between the archaeal ␣-amylases and their eubacterial and eukaryotic counterparts. Two evolutionary distance trees were constructed: (i) the first one based on the alignment of extracted best-conserved sequence regions (58 residues) comprising ␤2, ␤3, ␤4, ␤5, ␤7, and ␤8 strand segments of the catalytic (␣/␤) 8 -barrel and a short conserved stretch in domain B protruding out of the barrel in the ␤3 → ␣3 loop, and (ii) the second one based on the alignment of the substantial continuous part of the (␣/␤) 8 -barrel involving the entire domain B (consensus length: 386 residues). With regard to archaeal ␣-amylases, both trees compared brought, in fact, the same results; i.e., all family 13 ␣-amylases from domain Archaea were clustered with barley pI isozymes, which represent all plant ␣-amylases. The enzymes from Bacillus licheniformis and Escherichia coli, representing liquefying and cytoplasmic ␣-amylases, respectively, seem to be the further closest relatives to archaeal ␣-amylases. This evolutionary relatedness clearly reflects the discussed similarities in the amino acid sequences of these ␣-amylases, especially in the bestconserved sequence regions. Since the results for ␣-amylases belonging to all three domains (Eucarya, Eubacteria, Archaea) offered by both evolutionary trees are very similar, it is proposed that the investigated conserved sequence regions may indeed constitute the ''sequence fingerprints'' of a given ␣-amylase.

A new strain, exhibiting an intriguing pink-colored cell phenotype, was obtained after an encoding alpha-glucosidase gene from an archaebacteria Thermococcus hydrothermalis was cloned by functional complementation of a mal11 Saccharomyces cerevisiae mutant TCY70. The possible implications of the alpha-glucosidase on the cell wall were evaluated by infrared spectroscopy and data indicate a 30% decrease in mannoproteins and an increase in beta-glucans. The loss of mannoproteins was confirmed by experiments on cells deprived of peptidomannans. Modifications in the major components of the cell wall did not jeopardize cell viability. Such rapid optical spectroscopic method can be used to screen a wide range of yeast mutants.