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An Aspergillus oryzae RIB40 (NBRC100959) α-glucosidase (designed as AgdB)gene (agdB) was expressed at high levels in an A. oryzae host by self-cloning. The obtained transformant (MIBA1002) produced intracellular and extracellular α-glucosidase at levels 3-and 10-fold higher, respectively, than the parent host strain. The base sequence of agdB consisted of a 3036-kb structural gene containing three introns and encoding 963 amino acids, and the linear sequence thus obtained from these amino acids was identical to A. oryzae RIB40 unknown protein BAE64257.1. The amino acid sequence had 72% and 51% homology to α-glucosidase B from Aspernillus nidulans and Acremonium implicatum, respectively, which exhibit transglycosylation activity. The sequence has conserved residues specific to glucosyl hydrase family 31 (GH31) α-glucosidases. Tyr296 present in the β→α Loop1 in GH31 is important for transglycosylation. The enzyme produced 2.2% isomaltose, 0.4% maltotriose, and 0.3% kojibiose from 20% maltose substrate. This is the first report of the transglycosylation activity of α-glucosidase B cloned in A. oryzae (unknown protein BAE64257.1).

Summary Forty-four female students with a tendency for constipation (mean age, 20.263.3 y) were asked to consume 30 g test pickles daily for 2 wk and were divided into 3 groups: viable-cell intake subjects (n514, 3.0310 5 colony-forming units of viable LAB (lactic acid bacteria) cells per sample), dead-cells intake subjects (n515, viable cells were heat sterilized), and placebo-intake subjects (n515, LAB removed from the pickles). g-Aminobutyric acid content of 75.163.2 mg per sample was noted, with no marked difference between samples containing viable and dead cells. Natural killer (NK)-cell activity (% specific lysis) in serum from dead-cell intake subjects was 37.5617.0% before the start of the test-food intake and 47.7620.1% after intake, indicating statistically significant effects (p,0.01). However, viable-cell intake and placebo intake subjects showed no statistically significant difference. The number of days with bowel movements significantly increased from 3.861.5 to 4.961.8 d in the dead-cell intake group, whereas a slight change from 4.661.5 to 5.161.7 d was observed in the viable-cell intake group. Additionally, the feeling of incomplete evacuation fell and a refreshed feeling increased among the subjects with constipation. Thus, marked enhancement of NK-cell activity and improved bowel symptoms were observed in subjects consuming pickles containing dead LAB cells.

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