title: Cell wall α-1,3-glucan prevents α-amylase adsorption onto fungal cell in submerged culture of Aspergillus oryzae.
abstract: We have previously reported that α-amylase (Taka-amylase A, TAA) activity disappears in the later stage of submerged Aspergillus oryzae culture as a result of TAA adsorption onto the cell wall. Chitin, one of the major components of the cell wall, was identified as a potential factor that facilitates TAA adsorption. However, TAA adsorption only occurred in the later stage of cultivation, although chitin was assumed to be sufficiently abundant in the cell wall regardless of the submerged culture period. This suggested the presence a factor that inhibits TAA adsorption to the cell wall in the early stage of cultivation. In the current study, we identified α-1,3-glucan as a potential inhibiting factor for TAA adsorption. We constructed single, double, and triple disruption mutants of three α-1,3-glucan synthase genes (agsA, agsB, and agsC) in A. oryzae. Growth characteristics and cell wall component analysis of these disruption strains showed that AgsB plays a major role in α-1,3-glucan synthesis. In the ΔagsB mutant, TAA was adsorbed onto the mycelium in all stages of cultivation (early and later), and the ΔagsB mutant cell walls had a significantly high capacity for TAA adsorption. Moreover, the α-1,3-glucan content of the cell wall prepared from the wild-type strain in the later stage of cultivation was markedly reduced compared with that in the early stage. These results suggest that α-1,3-glucan is a potential inhibiting factor for TAA adsorption onto the cell wall component, chitin, in the early stage of submerged culture in A. oryzae.
authors.affiliation: Laboratory of Bioindustrial Genomics, Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Aoba-ku, Sendai 980-0845, Japan.
authors.forename: Silai
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Laboratory of Bioindustrial Genomics, Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Aoba-ku, Sendai 980-0845, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Sato
authors.affiliation: Laboratory of Bioindustrial Genomics, Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Aoba-ku, Sendai 980-0845, Japan.
authors.forename: Sakurako
authors.initials: S
authors.lastname: Ichinose
authors.affiliation: Laboratory of Bioindustrial Genomics, Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Aoba-ku, Sendai 980-0845, Japan.
authors.forename: Mizuki
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: Laboratory of Applied Microbiology, Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Aoba-ku, Sendai 980-0845, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Miyazawa
authors.affiliation: New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Yoshimi
authors.affiliation: Laboratory of Applied Microbiology, Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Aoba-ku, Sendai 980-0845, Japan; New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan.
authors.forename: Keietsu
authors.initials: K
authors.lastname: Abe
authors.affiliation: Laboratory of Bioindustrial Genomics, Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Aoba-ku, Sendai 980-0845, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Shintani
authors.affiliation: Laboratory of Bioindustrial Genomics, Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Aoba-ku, Sendai 980-0845, Japan. Electronic address: katsuya.gomi.a6@tohoku.ac.jp.
authors.forename: Katsuya
authors.initials: K
authors.lastname: Gomi
mesh_terms: D000327:Adsorption; D001236:Aspergillus oryzae / Q000166:cytology* / Q000201:enzymology / Q000235:genetics; D018929:Cell Culture Techniques; D002473:Cell Wall / Q000378:metabolism*; D005936:Glucans / Q000737:chemistry*; D005964:Glucosyltransferases / Q000235:genetics; D007101:Immersion; D009154:Mutation; D000516:alpha-Amylases / Q000737:chemistry* / Q000378:metabolism
chemical_list: D005936:Glucans; C045788:alpha-1,3-glucan; D005964:Glucosyltransferases; C020570:1,3-beta-glucan synthase; D000516:alpha-Amylases
keywords: Aspergillus oryzae; Cell wall; Submerged culture; α-1,3-Glucan; α-Amylase adsorption