Antitumor activity of polygalactosamine isolated from Paecilomyces sp. I-1 strain

Design of Lysosomotropic Macromolecular Prodrug of Doxorubicin Using N-Acetyl-α-1,4-Polygalactosamine as a Targeting Carrier to Hepatoma Tissue

α-1,4-Polygalactosamine (PGA) and N-acetylated α-1,4-polygalactosamine (NAPGA) are chitosan- and chitin-like biodegradable α-1,4-linked polysaccharides, respectively. Radioactivity of 14C-50% N-acetylated PGA injected into hepatomized mice, was found to accumulate more in the liver, kidney, ileum and hepatoma tumor tissues, compared with other organs. To provide a lysosomotropic macromolecular prodrug of doxorubicin (DXR) targeted to hepatoma tumor tissue, DXR was immobilized on water-soluble 6-O-carboxymethyl(CM)-NAPGA by Gly-Phe-Leu-Gly spacer groups (CM-NAPGA/Gly-Phe-Leu-Gly/DXR conjugate). The conjugate showed cathepsin B susceptible DXR release behavior and exhibited remarkable survival effects in mice bearing MH134Y hepatoma implanted by subcutaneous (s.c.) implantation/intravenous (i.v.) injection, compared with free DXR and CM-NAPGA-immobilized DXRs with pentamethylene spacer groups (CM-NAPGA/C5/DXR conjugate).

Structure of the polysaccharide isolated from the sheath of Sphaerotilus natans

A polysaccharide was isolated from the sheath of a sheathed bacterium, Sphaerotilus natans. The sheath polysaccharide (SPS) was composed of D-glucose and D-(N-acetyl)galactosamine in molar ratios of 1:4. Methylation linkage analysis revealed the presence of the residues of 4-linked glucose, 4-linked (N-acetyl)galactosamine, and 3-linked (N-acetyl)galactosamine in molar ratios of 1:3:1. The oligomer of SPS was prepared with an SPS-specific degrading enzyme from a sheath-degrading bacterium, Paenibacillus koleovorans. The oligomer was derivatized and subjected to fast atom bombardment-mass spectrometry to investigate the monosaccharide sequence of SPS. The structure of SPS was confirmed by nuclear magnetic resonance. The resulting data showed that SPS is a straight-chained basic polysaccharide constructed of a pentasaccharide repeating unit.

Brefeldin A, a cytotoxin produced by Paecilomyces sp. and Aspergillus clavatus isolated from Taxus mairei and Torreya grandis

Paecilomyces sp. and Aspergillus clavatus, which were isolated from Taxus mairei and Torreya grandis from southeast China, produced toxic metabolites when grown in liquid culture. Nuclear magnetic resonance techniques, infrared spectrometry, electrospray ionization mass spectroscopy and X-ray analysis identified brefeldin A, a bioactive metabolite produced by a number of fungal species belonging to the genera Alternaria, Ascochyta, Penicillium, Curvularia, Cercospora and Phyllosticta. This is the first report of the isolation of the cytotoxin from Paecilomyces sp. and A. clavatus. The relevance of brefeldin A to the association between these fungi and their host plants is discussed.