A concise synthesis of (-)-steviamine is reported along with the synthesis of its analogues 10-nor-steviamine, 10-nor-ent-steviamine and 5-epi-ent-steviamine. These compounds were tested against twelve glycosidases (at 143 μg mL(-1) concentrations) and were found to have in general poor inhibitory activity against most enzymes. The 10-nor analogues however, showed 50-54% inhibition of α-L-rhamn...

THF-gramicidin hybrids 2-4 with the L-THF amino acid 1 in positions 11 and 12 and compounds 5-8 with the D-THF amino acid ent-1 in positions 10 and 11 were synthesized and their ion channel properties were studied by single-channel-current analysis. The replacement of positions 11 and 12 by the L-THF amino acid 1 gave a strongly reduced channel performance. In contrast, replacement of positions...

Natural products isolation studies were performed on Dodonaea viscosa plant individuals sampled across seven different populations, which revealed considerable intraspecific variation in the terpene profiles D. viscosa. In total, 14 ent-labdane diterpenoids (seven of are previously unreported), four ent-kauranes (one is one rare norhopene, and two unreported monoterpenoid wax esters isolated. E...

Role of the tectorial membrane revealed by otoacoustic emissions recorded from wild-type and transgenic Tecta ENT/ENT mice ABSTRACT Distortion product otoacoustic emissions (DPOAE) were recorded from wild-type mice and mutant Tecta ENT/ENT mice with detached tectorial membranes (TM), under combined ketamine/xylaxine anaesthesia. In Tecta ENT/ENT mice DPOAEs could be detected above the noise flo...

W. S. H am am a Chemistry D epartm ent, Faculty of Science, M ansoura University, M ansoura, Egypt R eprint requests to Dr. W. S. H am am a. E-mail: Sinfac@ mum.mans.eun.eg Z. Naturforsch. 55b, 443-447 (2000); received January 25, 2000 6-Am inouracil, M annich Reaction, Pyrimido[4,5-d]pyrim idine The reaction of 6-am inouracil 1 with form aldehyde and secondary amines in ethanol at room tem per...

Ioana Duţan1,3 and Peter L. Biermann2,3 1University of Bucharest, Faculty of Physics Str. Atomiştilor, 405, RO-76900, Bucureşti-Mǎgurele, România 2University of Bonn Regina-Pacis-Weg, 3, D-53113, Bonn, Germany 3Max-Planck-Institute for Radioastronomy Auf dem Hűgel, 69, D-53121, Bonn, Germany [email protected]; [email protected] Abstra t The e ien y of a rapidly spinning Kerr b...

A human papillomavirus (HPV) infection is globally one of the most common causes sexually transmitted infections mucous membranes (genital, anal and oral). Over last decade, an increasing number young patients have been infected due to changes in sexual habits general population. The majority lesions are benign; however, substantial scientific evidence has suggested a role for HPV family carcin...

Mutants of Arabidopsis thaliana deficient in gibberellin synthesis (ga1-3 and ga1-6), and a gibberellin-insensitive mutant (gai) were compared to the wild-type (WT) Landsberg erecta line for flowering time and leaf number when grown in either short days (SD) or continuous light (CL). The ga1-3 mutant, which is severely defective in ent-kaurene synthesis because it lacks most of the GA1 gene, ne...