Structure of a peptidoglycan-related polysaccharide from <Emphasis Type="Italic">Providencia alcalifaciens</Emphasis> O45

A polysaccharide was isolated from the opportunistic human pathogen Providencia alcalifaciens O45:H26 by extraction with aqueous phenol and studied by sugar and methylation analyses along with ¹H and ¹³C NMR spectroscopy, including two-dimensional ROESY and H-detected ¹H,¹³C HSQC experiments. The polysaccharide contains N-acetylglu-cosamine and N-acetylmuramic acid (D-GlcpNAc3Rlac) amidated with L-alanine and has the following structure:

$\to 4) - \beta - D - GlcpNAc - (1 \to 4) - \beta - D - GlcpNAc3(Rlac - L - Ala) - (1 \to .$

The polysaccharide possesses a remarkable structural similarity to the bacterial cell wall peptidoglycan. It is not unique to the strain studied but is common to strains of at least four P. alcalifaciens O-serogroups (O3, O24, O38, and O45). No evidence was obtained that the polysaccharide is associated with the LPS, and hence it might represent a bacterial capsule component.

     

Reinvestigation of the O-antigens of Yersinia pseudotuberculosis: revision of the O2c and confirmation of the O3 antigen structures

Structures of the O-antigens of Yersinia pseudotuberculosis O2c and O3 were reinvestigated by NMR spectroscopy, including 2D (1)H,(1)H COSY, TOCSY, ROESY, (1)H,(13)C HSQC, and HMBC experiments. The following revised structure of the O2c tetrasaccharide repeating unit was established, which differs from the structure proposed earlier in the glycosylation pattern of the mannose residue at the branching point: where Abe stands for 3,6-dideoxy-d-xylo-hexose. The structure of the Y. pseudotuberculosis O3 antigen reported earlier was confirmed.     

Structure of the O-specific polysaccharide of the lipopolysaccharide of Rahnella aquatilis 95 U003

The O-polysaccharide of Rahnella aquatilis 95 U003 was obtained by mild acid degradation of the lipopolysaccharide and studied by sugar and methylation analyses, Smith degradation and (1)H and (13)C NMR spectroscopy, including 2D (1)H,(1)H COSY, TOCSY, ROESY, H-detected (1)H,(13)C HSQC and HMQC-TOCSY experiments. The O-polysaccharide was found to have a branched hexasaccharide repeating unit of the following structure:     

Structure of the glycerol phosphate-containing O-specific polysaccharide and serological studies on the lipopolysaccharides of Citrobacter werkmanii PCM 1548 and PCM 1549 (serogroup O14)

The O-specific polysaccharide was obtained by mild acid hydrolysis of the lipopolysaccharide of Citrobacter werkmanii PCM 1548 and PCM 1549 (serogroup O14) and found to contain D-glucose, D-glucosamine and glycerol-1-phosphate in molar ratios 2 : 2 : 1. Based on methylation analysis and 1H and 13C nuclear magnetic resonance spectroscopy data, it was established that the O-specific polysaccharides from both strains have the identical branched tetrasaccharide repeating unit with 3,6-disubstituted GlcNAc, followed by 2,4-disubstituted Glc residues carrying at the branching points lateral residues of Glc and GlcNAc at positions 6 and 2, respectively. Glycerol-1-phosphate is linked to position 6 of the chain Glc. All sugars have a beta configuration, except for the side-chain Glc, which is alpha. Serological studies revealed a close relatedness of the lipopolysaccharides of C. werkmanii PCM 1548 and PCM 1549, both belonging to serogroup O14. In immunoblotting, anti-C. werkmanii PCM 1548 serum showed no cross-reactivity with the O-polysaccharide bands of the lipopolysaccharides of Citrobacter youngae PCM 1550 (serogroup O16) and Hafnia alvei PCM 1207, also containing a lateral glycerol phosphate residue.     

Structural diversity and endotoxic activity of the lipopolysaccharide of Yersinia pestis

The endotoxic activity of the lipopolysaccharides (LPS) with defined chemical structure from Yersinia pestis strains of various subspecies differing in their epidemic potential was studied. The LPS of two strains of Y. pestis ssp. caucasica and ssp. altaica, whose structures have not been studied earlier, were analyzed by high-resolution mass spectrometry. In addition to reported structural changes, an increase in the degree of LPS phosphorylation was observed when strain I-2377 (ssp. altaica) was cultivated at an elevated temperature. A high tumor necrosis factor alpha(TNF-alpha)-inducing activity observed for LPS samples from Y. pestis cultures grown at 25 degrees C correlated with an increased degree of lipid A acylation, particularly, with the presence of the hexaacyl form of lipid A, which was absent from the LPS when bacteria were cultivated at 37 degrees C. No correlation was found between the lethal toxicity of the LPS in vivo and its ability to induce TNF-alpha production in vitro.     

High IFN－α expression is associated with the induction of experimental autoimmune uveitis （EAU） in Fischer 344 rat

INTRODUCTIONThe CD4 T cells can be subdivided intoTh1 and Th2 subsets based on their secreted cy-tokine profile. Th1 cells characteristical1y secreteInterferonry (IFN--ry), whereas Th2 cells maiuly pro--duce IL--4[1]. IL-12 po1arizes the differentiation ofnaitre, CD4 T cells towards Th1 pathWay, in con-trast IL--4 directs T cell differentiation towards Th2pathWay The broken balance between Th1 and Th2immune responses and predominant Th1 responseare crucial factors in initiation…     

Structure of the O-polysaccharide and classification of Proteus mirabilis strain G1 in Proteus serogroup O3.

The O-chain polysaccharide of the lipopolysaccharide (LPS) of a previously nonclassified strain of Proteus mirabilis termed G1 was studied by sugar analysis and 1H and 13C NMR spectroscopy, including 2D COSY, TOCSY, rotating-frame NOE (ROESY), H-detected 1H,13C HMQC, and heteronuclear multiple-bond correlation (HMBC) experiments. The following structure of the polysaccharide was established: [carbohydrate structure: see text] where D-GalA6(L-Lys) stands for N(alpha)-(D-galacturonoyl)-L-lysine. The structure of the O-polysaccharide of P. mirabilis G1 is similar, but not identical, to that of P. mirabilis S1959 and OXK belonging to serogroup O3. Immunochemical studies with P. mirabilis G1 and S1959 anti-(O-polysaccharide) sera revealed close LPS-based serological relatedness of P. mirabilis G1 and S1959, and therefore it was suggested to classify P. mirabilis G1 in serogroup O3 as a subgroup. P. mirabilis G1 and S1959 anti-(O-polysaccharide) sera also cross-reacted with LPS of P. mirabilis strains from two other serogroups containing D-GalA6(L-Lys) in the O-polysaccharide or in the core region.     

Identification and expression of epidermal growth factor gene in mouse testis

INTRODUCTIONEpidermalgrowthfactor(EGF)wasinitiallyisolatedandpurifiedfromthesubmaxillarygland(SMG)ofmalemouse[1].Itisapolypeptidecomposedof53aminoacidresidues[2].Itinfluencescellproliferationanddifferentiationandmodulatesthegrowthanddevelopmentofmammalianorgans[3--7].AnoteworthyfindingisthatextirpationofmouseSMGresultsinamarkedreductionofserumEGFconcentrationassociatedwithanimpairedspermatogenesis[3].ThisfindingsuggeststhatEGFmayregulatespermproductionanddifferentiation.Inhumantest…