Journal of Microbiology

Research Support, Non-U.S. Gov't

Transcriptional Regulation of fksA, a β-1,3-Glucan Synthase Gene, by the APSES Protein StuA during Aspergillus nidulans Development: Bum-Chan Park , Yun-Hee Park , Soohyun Yi , Yu Kyung Choi , Eun-Hye Kang , Hee-Moon Park; J. Microbiol. 2014;52(11):940-947. Published online October 31, 2014; DOI: https://doi.org/10.1007/s12275-014-4517-y

Abstract: The temporal and spatial regulation of β-1,3-glucan synthesis plays an important role in morphogenesis during fungal growth and development. Northern blot analysis showed that the transcription of fksA, the gene encoding β-1,3-glucan synthase in Aspergillus nidulans, was cell-cycle-dependent and increased steadily over the duration of the vegetative period, but its overall expression during the asexual and sexual stages was fairly constant up until the time of transcription cessation. In an A. nidulans strain mutated in the eukaryotic bHLH-like APSES transcription factor stuA1, the transcriptional level of fksA, and consequently the content of alkali-insoluble cell wall β-glucan, significantly increased at the conidial chain formation and maturation stage. Electrophoretic mobility shift assays revealed that StuA was bound to StREs (StuA Response Elements) on the fksA promoter region. Promoter analysis with sGFP-fusion constructs also indicated the negative regulation of fksA expression by StuA, especially during asexual development. Taken together, these data suggest that StuA plays an important role in cell wall biogenesis during the development of A. nidulans, by controlling the transcription level of fksA.

Antifungal activities of peptides with the sequence 10-17 of magainin 2 at the N-termini against aspergillus fumigatus: Lee, Myung Kyu , Lee, Dong Gun , Shin, Song Yub , Lee, Sung Gu , Kang, Joo Hyun , Hahm, Kyung Soo; J. Microbiol. 1996;34(3):274-278.

Abstract: Two peptides, MA-inv AND MA-ME, with the sequence 10-17 of maganin 2 at their-N-termini were designed and synthesized. The peptides had higher antifungal activities against Aspergilus fumigatus without hemolytic activities. The minimal inhibition concentratory (MIC) values of both peptides against A. fumigatus were 5 ㎍/ml, whereas those of the native peptides, magainin 2 and melittin, were 10㎍/ml. At 3 ㎍/ml, MA-inv and MA-ME inhibited the mycelium growth of A. fumigatus by 94.6% and 97.3% respectively, whereas magainin 2 and melittin inhibited by 62.2% and 32.4, respectively. MA-inv showed up to 80% inhibition of (1, 3)-β-D-glucan synthase activity of A. fumigatus. The peptides also showed up to 80% inhibition of (1, 3)-β-D glucan synthase activity of A. fumigatus. The peptides also showed antifungal activities for other fungi of Aspergillus sp. However, the antibiotic activities of MA-ME against Escherichia coli, Bacillus subtilis and Fusarium oxysporum were more effective than those of MA-inv, suggesting that the C-terminal sequences of MA-inv and MA-ME may also influence their antibiotic activities. These results suggest that the N-terminal sequence of the designed peptides, KKFGKAFV, is important for their antifungal activities against A. fumigatus and their C- terminal sequences are related to the organism selectivity.

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