Search

Hypercohin K (1), the first polycyclic polyprenylated acylphloroglucinol possessing a unique spiro-fused cyclopropane ring, together with hyphenrone L (2) representing the most complex congeners featured with a hexacyclic core, was isolated from Hypericum cohaerens. The structure of 1 was elucidated by extensive MS and NMR spectroscopic data. The absolute configuration was defined by comparison of the experimental and calculated ECD. Compound 1 was evaluated for the inhibitory activities against acetylcholinesterase and four human tumor cell lines. (C) 2015 Elsevier Ltd. All rights reserved.

Candida albicans is an opportunistic human fungal pathogen. The ability to switch among multiple cellular forms is key to its pathogenesis. The Dbf4-dependent protein kinase gene CDC7 is conserved due to its role in initiating DNA replication. Because a C. albicans Cdc7 (Cacdc7) homozygous null was not viable, we generated a C. albicans strain with a deleted C. albicans CDC7 (CaCDC7) allele and an expression-repressible allele. Surprisingly, cells of the strain grew as hyphae under the repressed conditions. The in vitro kinase assays confirmed that CaCdc7 (K232) and CaCdc7 (T437) are critical for catalytic and phosphoacceptor of activation activity, respectively. C. albicans cells formed hyphae when expressing either the catalytically inactive CaCdc7 (K232R) or the phosphoacceptor-deficient CaCdc7 (T437A). While CaCdc7 interacted with CaDbf4, cells of the strain in which CaCDC7 was repressed were not rescued by constitutively expressing C. albicans DBF4 or vice versa. We conclude that CaDBF4-dependent CaCDC7 is an essential gene suppressing the hyphal development.

Hypercohin K (1), the first polycyclic polyprenylated acylphloroglucinol possessing a unique spiro-fused cyclopropane ring, together with hyphenrone L (2) representing the most complex congeners featured with a hexacyclic core, was isolated from Hypericum cohaerens. The structure of 1 was elucidated by extensive MS and NMR spectroscopic data. The absolute configuration was defined by comparison of the experimental and calculated ECD. Compound 1 was evaluated for the inhibitory activities against acetylcholinesterase and four human tumor cell lines. (C) 2015 Elsevier Ltd. All rights reserved.