Helga Kochanowski

EXPRESSION OF MELK, A NEW PROTEIN KINASE, DURING EARLY MOUSE DEVELOPMENT

A new gene named maternal embryonic leucine zipper kinase, Melk, has been recently identified (Heyer et al. [1997] Mol. Reprod. Dev. 47:148–156). As a basis for further study of the function of the gene, we have examined the expression of Melk across a wide range of embryonic stages, from the ovulated egg and 2‐cell embryo through the gastrulation and early organogenesis stages, by in situ hybridization and immunohistochemistry. Melk is expressed in a spatially and temporally specific pattern during mammalian embryogenesis. The strongest expression was detected during maturation of oocytes and preimplantation development. Given its expression pattern, Melk may play an important role during preimplantation embryonic development. Dev Dyn 1999;215:344–351.

The structure of the homopolymeric O-specific chain from the phenol soluble LPS of the Rhizobium loti type strain NZP2213

Abstract The O-specific polysaccharide of the phenol soluble lipopolysaccharide (LPS) (LPS-P) of the Rhizobium loti NZP2213 strain consists of a homopolymeric chain of α-1, 3-linked units of 2-O-acetyl-6-deoxy- l -talopyranose, very probably terminated by a single unit of 2-O-acetyl-6-deoxy- l -talopyranose. The hydrophobic character of the long O-chains explains the phenol solubility of LPS-P, in contrast to the water solubility of LPS-W, which is of R-character and accordingly lacks the O-acetyl-6d-talose units.

NMR investigation of the 6-deoxy-l-talose-containing O45, O45-related (O45rel), and O66 polysaccharides of Escherichia coli

The structures of the 6-deoxytalose-containing O-specific polysaccharides from the O45 antigen, an O45-related antigen (O45rel), and the O66 antigen (lipopolysaccharides, LPSs) of Escherichia coli were elucidated by chemical characterization and by one- and two-dimensional 1H and 13C NMR spectroscopy. The O45 and O45-related polysaccharides have the following general structure: [formula: see text] For the O45 antigen, X is alpha-D-FucpNAc and for the O45-related antigen, X is beta-D-GlcpNAc. The structure of the O66 polysaccharide is [formula: see text]

Structure of the O16 polysaccharide from Escherichia coli O16:K1: An NMR investigation

The polysaccharide moiety of the O16 antigen (lipopolysaccharide) consists of D-glucopyranose, D-galactofuranose, L-rhamnopyranose, and 2-acetamido-2-deoxy-D-glucopyranose in the molar ratios 1:1:1:1. It is O-acetylated with one acetyl group per repeating unit. One- and two-dimensional NMR spectroscopy of the polysaccharide before and after O-deacetylation showed that the O16 polysaccharide has the structure [formula: see text]

The structure of the O-specific polysaccharide from Thiobacillus sp. IFO 14570, with three different diaminopyranoses forming the repeating unit

The O-specific polysaccharide, liberated by mild acid hydrolysis of the lipopolysaccharide (LPS-P) from Thiobacillus sp. IFO14570 as isolated from the phenol phase after phenol-water extraction, is shown to have a linear trisaccharide repeating-unit containing three different diamino sugars, namely 2,4-diacetamido-2,4-dideoxyglucuronic acid, 2-acetamidino-4-acetamido-2,4,6-trideoxyglucopyranose, and 2,3-diacetamido-2,3-dideoxyglucuronic acid in the molar ratio of 1:1:1. On the basis of 1H and 13C spectroscopy, including 2D COSY and coherent transfer (RCT)COSY, 1D NOE in the difference mode, and 2D rotating frame NOE(ROESY) the sequence, the type of substitution, and the position of the acetamidino group could be determined. These experiments allowed formulation of the following structure for the O-specific polysaccharide, although the depicted D configuration of the three sugar residues is not yet proven: [structure: see text]

Structure of the O-specific side chain of the Escherichia coli O128 lipopolysaccharide

The O-specific polysaccharide isolated from Escherichia coli O128 lipopolysaccharide contains D-galactose, L-fucose, and 2-acetamido-2-deoxy-D-galactose in the molar ratios 2:1:2. The primary structure of the O-specific polysaccharide from E. coli was established by compositional analysis, methylation analysis, together with 1H and 13C NMR spectroscopy including two-dimensional shift-correlated and one-dimensional NOE spectroscopy. The polysaccharide moiety was found to consist of a tetrasaccharide backbone containing D-galactose and 2-acetamido-2-deoxy-D-galactose, with L-fucose as a side chain in a branched pentasaccharide repeating unit having the following structure: [formula: see text]

Structure of the O83-specific polysaccharide of Escherichia coli O83:K24:H31.

The polysaccharide moiety of the O83 antigen (lipopolysaccharide, LPS) consists of D-glucose, D-galactose, 2-acetamido-2-deoxy-D-glucose, and D-glucuronic acid in the molar ratios 1:2:1:1. Methylation analysis of the polysaccharide and derived oligosaccharides as well as one- and two-dimensional 1H and 13C NMR spectroscopy of the polysaccharide at pD 1 and 6 showed that the O83 polysaccharide has the primary structure-->6)-alpha-D-Glc p-(1-->4)-beta-D-Glc pA-(1-->6)-beta-D-Gal p-(1-->4)-beta-D- Gal p-(1-->4)-beta-D-Glc pNAc-(1-->.

Teichuronic acid of the cell wall of Actinoplanes brasiliensis

The cell wall of Actinoplanes brasiliensis INA 3802 contains a teichuronic acid of unusual structure, as determined in a nondestructive way by 1H- and 13C-NMR spectroscopy. The polysaccharide comprises six tetrasaccharide units of the following composition: -->6)-alpha-D-Glcp-(1-->4)-beta-D-2,3-diacetamido- 2,3-dideoxyGlcpA-(1-->4)-alpha-D-2,3-diacetamido-2,3-dide oxyGlcp-(1-->4)-beta- D-2,3-diacetamido-2,3-dideoxyManpA. A polymer of such structure has not heretofore been reported for procaryotic cell walls.

Structural comparison of the O4-specific polysaccharides from E. coli O4:K6 and E. coli O4:K52

Two distinct forms of the O4 antigen (LPS) from E. coli were analysed by 1H and 13C NMR spectroscopy. Both consisted of D-glucose, L-rhamnose, 2-acetamido-2,6-dideoxy-L-galactose (L-FucNAc), and 2-acetamido-2-deoxy-D-glucose. Their structures were found to be [formula: see text]. In the O4-specific polysaccharide from E. coli O4:K3, O4:K6, and O4:K12, X is alpha-D-Glcp. In the O4 specific polysaccharide from E. coli O4:K52, the rhamnose residue is not substituted (X = H).

Structure of the O-specific polysaccharide of the O23 antigen (LPS) from Escherichia coli O23:K?:H16

The polysaccharide moiety of the O22-antigen (lipopolysaccharide, LPS) consists of 2-acetamido-2-deoxy-D-galactose, D-glucuronic acid, D-glucose, and D-galactose in the molar ratios 2:1:1:1. Methylation analysis as well as 1D and 2D NMR spectroscopy showed that the O22 polysaccharide has the primary structure [formula: see text]