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Biomedical subjects

W Kraus

Publications and source records attributed to W Kraus.

At least 55 records · Page 3Linked to original sources
PubMed1990

Identification of an epitope of type 1 streptococcal M protein that is shared with a 43-kDa protein of human myocardium and renal glomeruli.

The localization of opsonic and tissue-cross-reactive epitopes within the amino terminus of type 1 streptococcal M protein was investigated by using murine mAb raised against synthetic peptides of type 1 M protein. Two mAb (IIIA2 and IIIB8) reacted with epitopes located within amino acid residues 1-12 of type 1 M protein. These antibodies opsonized type 1 streptococci and did not cross-react with human kidney and heart tissue. Another mAb (IC7) reacted with mesangial cells of renal glomeruli and human myocardium. The cross-reactive epitope of mAb IC7 was localized to position 13-19, indicating that it is not the same epitope as the previously described vimentin-cross-reactive epitope at position 23-26 of type 1 M protein. In Western blots of mesangial cell and myocardial proteins, mAb IC7 cross-reacted with a 43-kDa protein. Neither vimentin nor actin inhibited the binding of mAb IC7 to the cross-reactive protein, as determined by Western blot or immunofluorescence inhibition tests. These results provide evidence that type 1 M protein contains at least one autoimmune epitope shared with both human glomeruli and myocardium.

Amino Acid Sequence↗
PubMed1990

Triterpenoidal Constituents of Diploclisia glaucescens.

The pentacyclic triterpenoids serjanic acid and phytolaccagenic acid as well as a new glycoside, 3- O-beta- D-glucopyranosylphytolaccagenic acid have been isolated from the stem of DIPLOCLISIA GLAUCESCENS (Bl.) Diels (Menispermaceae). New spectroscopic data are furnished for serjanic acid and phytolaccagenic acid.

Journal Article↗
PubMed1989

Autoimmune sequence of streptococcal M protein shared with the intermediate filament protein, vimentin.

The crossreactivity of antibodies against a renal autoimmune epitope of Streptococcus pyogenes M protein with glomerular mesangial cells was investigated. The antibodies directed against the amino acid sequence Ile-Arg-Leu-Arg of the nephritogenic type 1 M protein reacted in a fibrillar pattern with mesangial cells cultured from isolated glomeruli. In Western blots of urea-extracted mesangial proteins, the antibodies reacted with a 56-kD protein. Monoclonal and polyclonal antibodies identified the 56-kD mesangial protein as vimentin. Two synthetic peptides of human vimentin containing the sequence Arg-Leu-Arg reacted with the autoimmune antibodies raised against a streptococcal M protein peptide. These results provide evidence that the intermediate filament protein vimentin shares autoimmune epitopes with streptococcal M protein.

Amino Acid Sequence↗
PubMed1989

Vimentin-cross-reactive epitope of type 12 streptococcal M protein.

The NH2-terminal amino acid sequence of type 12 M protein was determined by automated Edman degradation of a 38-kilodalton polypeptide fragment purified from a limited pepsin digest of intact type 12 streptococci. The sequence of the first 13 amino acid residues of the polypeptide confirmed that predicted by the nucleotide sequence of the mature type 12 M protein. A chemically synthesized peptide copying the NH2-terminal 25 residues, SM12(1-25)C, evoked opsonic antibodies against type 12 streptococci as well as renal glomerular cross-reactive antibodies. The serum from one of six rabbits reacted in immunofluorescence tests with human glomeruli in a mesangial staining pattern. The cross-reactive antibodies were completely inhibited by the immunizing peptide and absorption with type 12 streptococci. Subpeptides of the 25-residue synthetic peptide were without inhibitory effect, suggesting that the cross-reactive antibodies are directed against a conformational epitope of SM12(1-25)C. Anti-SM12(1-25)C antisera reacted specifically with the intermediate filament protein vimentin extracted from mesangial cells. None of the cross-reactions of anti-SM12(1-25)C were inhibited by a synthetic peptide SM1(1-26)C of type 1 M protein, which was previously shown to share a cross-reactive epitope with vimentin. These results indicate that type 12 M protein contains at least one vimentin cross-reactive epitope that is clearly distinct from the tetrapeptide epitope shared with vimentin by type 1 M protein.

Amino Acid Sequence↗
PubMed1988

Comparison of the leader sequences of four group A streptococcal M protein genes.

The 5' portions and flanking sequences of genes encoding types 1, 12, 24, and 6 M proteins were compared. Although the DNA sequences encoding the amino-termini of the mature M proteins had no obvious similarity, upstream sequences, and those encoding the signal peptides (leader sequences) of the four M protein genes had considerable similarity. In general, the 5' ends of all the leader sequences were more conserved than the 3' ends, although the M6 and M24 leader sequences had identical 3' ends. Sequence similarity among the deduced amino acid sequences of the four signal peptides was more extensive than the corresponding DNA sequences. We found that strict DNA similarity among all four sequences extended only to the ends of the hydrophilic amino-terminal regions of the signal peptides, but that amino acid sequence conservation continued to the ends of the respective hydrophobic cores. With the exception of the M6 and M24 sequences, the regions adjacent to the signal peptidase cleavage sites were highly variable.

Amino Acid Sequence↗
PubMed1988

Protective and autoimmune epitopes of streptococcal M proteins.

Several rheumatogenic serotypes of streptococcal M protein have been shown to contain both protective and cardiac tissue crossreactive epitopes. By synthesizing peptides copying different regions of M protein polypeptides, we were able to localize the protective and heart crossreactive epitopes. Some epitopes are only opsonic, some are only crossreactive, whereas others are both opsonic and tissue crossreactive. Multivalency of vaccines can be obtained by synthesizing protective peptides of one M serotype in tandem with protective peptides of other M serotypes. Such hybrid peptides evoke protective immune responses against the related streptococci without evoking tissue crossreactive immunity.

Animals↗
PubMed1988

Renal autoimmune epitope of group A streptococci specified by M protein tetrapeptide Ile-Arg-Leu-Arg.

The renal glomerular cross-reactivity of the amino-terminal region of type 1 streptococcal M protein was investigated. Antisera raised in rabbits against a synthetic peptide representing residues 1-26 and a peptide from which residues 20-22 had been omitted during synthesis were capable not only of opsonizing type 1 streptococci but also of reacting in immunofluorescence tests with human renal glomeruli. The cross-reactions were completely inhibited by the immunizing peptides. By using additional synthetic peptides in these inhibition studies, the glomerular cross-reactive epitope was localized to a tetrapeptide sequence Ile-Arg-Leu-Arg at positions 23-26. A number of synthetic M1 peptides containing the tetrapeptide sequence were inhibitory, whereas the M1 peptides lacking the sequence or unrelated tetrapeptides Arg-Gly-Asp-Ser or Arg-Gly-Phe-Ser were without effect. Furthermore, Ile-Arg-Leu-Arg affinity-purified antibodies reacted with renal glomeruli, and the reactivity was inhibited by the tetrapeptide as well as by type 1 M protein. These results indicate that a renal glomerular autoimmune epitope resides in a tetrapeptide Ile-Arg-Leu-Arg near the amino terminus of type 1 streptococcal M protein.

Amino Acid Sequence↗
PubMed1987

Sequence and type-specific immunogenicity of the amino-terminal region of type 1 streptococcal M protein.

The NH2-terminal sequence of type 1 M protein was determined by automated Edman degradation of purified polypeptide fragments extracted from whole streptococci by limited digestion with pepsin. Three polypeptide fragments were purified by slab gel electrophoresis on sodium dodecyl sulfate (SDS) polyacrylamide followed by electroelution. The purified fragments migrated as 28-, 25-, and 23.5-kDa fragments, respectively. Each of the fragments inhibited opsonization of a diluted antiserum prepared in rabbits by immunization with whole type 1 streptococci. The amino-terminal sequences of the peptide fragments were confirmed by comparison with the primary structure predicted from the nucleotide sequence of the type 1 M protein structural gene. The 28-kDa fragment contained the NH2-terminal asparagine residue of the processed type 1 M protein, whereas the NH2-terminal sequences of the 25- and 23.5-kDa peptides began at residues 27 and 36, respectively. A seven-residue periodicity with respect to polar and nonpolar residues was observed beginning at residue 22 and, therefore, the secondary structural potential of type 1 M protein is similar to that reported for other M proteins. In contrast to the other M proteins, however, identical repeats were rare, the longest sequence identity consisting of a three-amino acid acid sequence Lys-Asp-Leu at positions 30-32 repeated once at positions 65-67. A 23-residue synthetic peptide of the amino-terminus of the type 1 M protein evoked opsonic antibodies against type 1 streptococci. These results indicate that the NH2-terminal region of type 1 M protein retains the secondary structural characteristics of other M serotypes. Moreover, it contains epitopes that evoke protective immune responses. Our studies may have bearing in the development of safe and effective vaccines against group A streptococcal infections.

Amino Acid Sequence↗
PubMed1987

[Sonographic study of Béclard's nucleus as a method of determining the maturity of the newborn infant].

The size of the distal femoral epiphysis is an important criterion for determining the maturity of a neonate. The distal femoral epiphysis has been demonstrated and measured sonographically in two planes during the first month of life in 174 neonates. The sum of the epiphyseal diameters has been related to gestational age. The average sum of the sagittal and transverse diameter of both distal femoral epiphysis was 10.9 mm in the 35th week (standard deviation 7.6 mm) and increases to 38.4 mm at 43 weeks (standard deviation 6.3 mm). Linear regression of the mean values of the sum of the epiphyseal diameters y against gestational age x shows a correlation coefficient of 0.95 (regression gradient y = -117.7 + 3.7 x). Sonographic demonstration and measurements of the distal femoral epiphyses is a valid alternative to radiological examination.

Epiphyses↗
PubMed1987

Two distinct transpeptidation reactions during murein synthesis in Escherichia coli.

Murein synthesized in ether-permeabilized cells of Escherichia coli deficient in individual penicillin-binding proteins (PBPs) and in the presence of certain beta-lactam antibiotics was analyzed by high-pressure liquid chromatography separation of the muramidase split products. PBP 1b was found to to be the major murein synthesizing activity that was poorly compensated for by PBP 1a. A PBP 2 mutant as well as mecillinam-inhibited cells showed increased activity in the formation of oligomeric muropeptides as well as UDP-muramylpeptidyl-linked muropeptides, the reaction products of transpeptidation, bypassing the lipid intermediate. In contrast, penicillin G and furazlocillin severely inhibited these reactions but stimulated normal dimer production. It is concluded that two distinct transpeptidases exist in E. coli: one, highly sensitive to penicillin G and furazlocillin, catalyzes the formation of hyper-cross-linked muropeptides, and a second one, quite resistant to these antibiotics, synthesizes muropeptide dimers.

Amdinocillin↗