白麹菌Aspergillus luchuensis mut. kawachiiのク エン酸輸送体に関する研究
2
0
0
全文
(2) （学位第３号様式）. 学 氏. 名. 題. 目. 位. 論. 文. 要. 旨. Chihiro Kadooka. Studies on citrate transporters in the white koji fungus, Aspergillus luchuensis mut. kawachii. A white koji fungus, Aspergillus luchuensis mut kawachii (A. kawachii) is used for production of shochu, a Japanese traditional distilled spirit. A. kawachii was isolated as an albino mutant from the black koji fungus, Aspergillus luchuensis, and they produce a large amout of citric acid. This feature is important because shochu is mainly produced in relatively warm areas of Japan, such as Kyushu. In this study, firstly, we found that A. kawachii produces black colored conidia by complementation of the wild type pksP gene, which encodes a polyketide synthase involved in the melanin. biosynthesis. The pksP complementation did not affect the. colony size or conidial surface structure in A. kawachii, but did caused an increase in the number of conidia per colony area. Moreover, the conidia of pksP complementation and overexpression strains showed higher resistance against ultraviolet light, hydrogen peroxide, and ion beams than that of the control strain. Next, we characterized citrate transporters CtpA and YhmA in A. kawachii. In biochemical analysis using purified CtpA and YhmA, we identified their citrate transport activity. Disruption of ctpA and yhmA caused deficient hyphal growth and conidium formation with reduced mycelial weight-normalized citrate production. Because we could not obtain double knockout strain, we constructed conditional double knockout strain using the Tet-On promoter system. Knockdown of ctpA and yhmA resulted in a severe growth defect on minimal medium with significantly reduced acetyl-CoA levels; however, we subsequently found that the severe growth defect was relieved by addition of acetate or lysine, which could remedy the acetyl-CoA level. These results indicate that CtpA and YhmA are mitochondrial citrate transporters involved in citric acid production and that transport of citrate from mitochondria to the cytosol plays an important role in acetyl-CoA biogenesis in A. kawachii. Finally, we characterized the role of putative methyltransferase LaeA for citric acid. hyperproduction in A. kawachii. The ΔlaeA strain exhibited a significant reduction in citric acid productivity. Cap-analysis gene expression (CAGE) revealed that laeA is required for the gene expression of a putative citrate exporter encoding cexA. The deficit in the productivity of citric acid by the ΔlaeA strain was rescued by the overexpression of cexA. In addition, ChIP-qPCR analysis indicated that LaeA regulates the expression of cexA via controls the euchromatin/heterochiromatin ratio. These results indicate that LaeA is involved in citric acid production through epigenetic regulation of cexA in A. kawachii..
(3)
関連したドキュメント
The measurement studies reported in this thesis employed Confirmatory Factor Analysis (CFA) to investigate the psychometric properties of the following instruments: 1) the
We have analyzed the national wide estimated incidence of T1D by using data from the government-subsidized Specified Pediatric Chronic
Taken together, these results indicate that FeMATE1 is involved in the Al-activated citrate secretion in the roots for external Al detoxification, while FeMATE2 is
These results indicate that yukimuro storage is effective to keep the quality and flavor of buckwheat grain, and that results from the conditions of both cold and high humidity in
12】a(oun,Richlcr&V趣nAndel,ノ
These$ results$ indicate$ that$ NKX233$ plays$ roles$ during$ the$ tooth$ cusp$ formation$ via$ Eda$
Students' menus were of four different styles; Japanese food which was westernized and fatty at present; convenience store food which was composed of daily box lunches,
In their study, the L2 Motivational Self System explained learners’ English proficiency more than SRL skills; learners’ Ideal L2 self (the intent to succeed in language
