d-Galacturonic Acid as a Highly Reactive Compound in Nonenzymatic Browning. 1. Formation of Browning Active Degradation Products

Reduction of uronic acid residues in permethylated polysaccharides from Sterculiaurens and S. caudata gums, followed by transformation of the resulting hexose into 6-deoxy-6-iodohexose residues, affords modified polysaccharides that undergo depolymerization on treatment with zinc dust. The main products after reduction with sodium borohydride are hexenitolterminated oligosaccharides. Their structures have been assigned as members of a series of O-[α-L-rhamnopyranosyl]-(1 → 3)-1,2-dideoxyhex-1-enitol derivatives, with and without attendant β-D-galactopyranosyl substituents, on the basis of nuclear magnetic resonance and mass spectral data and compositional analysis of trideuteriomethylated derivatives. The structures of the polysaccharides have been reassessed in the light of these and other experiments, and may now be formulated as containing a backbone of alternating 4-linked α-D-galacturonic acid and 2-linked α-L-rhamnopyranose residues bearing a minimum of three types of side chains attached at specific sites. Characterization of some of the degradation products provides evidence that limited degradation had occurred during methylation of the glycuronans.

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Characterization of a Ralstonia solanacearum Operon Required for Polygalacturonate Degradation and Uptake of Galacturonic Acid

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2003.16.6.536 ◽

2003 ◽

Vol 16 (6) ◽

pp. 536-544 ◽

Cited By ~ 53

Author(s):

Enid T. González ◽

Caitilyn Allen

Keyword(s):

Ralstonia Solanacearum ◽

Cell Walls ◽

Galacturonic Acid ◽

Degradation Products ◽

Plant Cell Walls ◽

Reaction Products ◽

Wild Type ◽

Pathogen Virulence ◽

Wild Type Parent

The bacterial wilt pathogen Ralstonia solanacearum produces three extracellular polygalacturonases (PGs): PehA, PehB, and PehC. All three PGs hydrolyze pectin's polygalacturonic acid backbone, but each releases different reaction products. PehA and PehB contribute significantly to pathogen virulence, probably by facilitating root invasion and colonization. To determine the collective contribution of PGs to virulence and saprophytic survival, we cloned, characterized, and mutated the R. solanacearum pehC gene, which encodes a distinctive monogalacturonate-releasing exo-PG. The virulence of a pehC mutant on tomato was indistinguishable from that of its wild-type parent; thus, this exo-PG alone does not contribute significantly to wilt pathogenesis. Unexpectedly, a completely PG-deficient triple pehA/B/C mutant was slightly more virulent than a pehA/B mutant. PehC may degrade galacturonide elicitors of host defense, thereby protecting the pathogen from plant antimicrobial responses. A galacturonate transporter gene, exuT, is immediately downstream of pehC and the two genes are co-transcribed. It has been hypothesized that galacturonic acid released by PGs from plant cell walls nourishes bacteria during pathogenesis. To separate the pectolytic and nutrient-generating roles of the PGs, we made an exuT mutant, which still produces all three isozymes of PG but cannot uptake PG degradation products. This exuT mutant had wild-type virulence on tomato, demonstrating that metabolism of galacturonic acid does not contribute significantly to bacterial success inside the plant.

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Collagen degradation products modulate matrix metalloproteinase expression in cultured articular chondrocytes

Journal of Orthopaedic Research® ◽

10.1002/jor.20001 ◽

2005 ◽

Vol 24 (1) ◽

pp. 63-70 ◽

Cited By ~ 54

Author(s):

M. Fichter ◽

U. Körner ◽

J. Schömburg ◽

L. Jennings ◽

A. A. Cole ◽

...

Keyword(s):

Matrix Metalloproteinase ◽

Articular Chondrocytes ◽

Degradation Products ◽

Collagen Degradation ◽

Collagen Degradation Products

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Structural Studies of Fibrinolysis by Electron and Light Microscopy

Thrombosis and Haemostasis ◽

10.1055/s-0037-1615843 ◽

1999 ◽

Vol 82 (08) ◽

pp. 277-282 ◽

Cited By ~ 37

Author(s):

Yuri Veklich ◽

Jean-Philippe Collet ◽

Charles Francis ◽

John W. Weisel

Keyword(s):

Electron Microscopy ◽

Light Microscopy ◽

Plasminogen Activator ◽

Structural Changes ◽

Molecular Mechanisms ◽

Degradation Products ◽

Molecular Model ◽

Three Dimensional ◽

Tissue Type ◽

Type Plasminogen Activator

IntroductionMuch is known about the fibrinolytic system that converts fibrin-bound plasminogen to the active protease, plasmin, using plasminogen activators, such as tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen activator. Plasmin then cleaves fibrin at specific sites and generates soluble fragments, many of which have been characterized, providing the basis for a molecular model of the polypeptide chain degradation.1-3 Soluble degradation products of fibrin have also been characterized by transmission electron microscopy, yielding a model for their structure.4 Moreover, high resolution, three-dimensional structures of certain fibrinogen fragments has provided a wealth of information that may be useful in understanding how various proteins bind to fibrin and the overall process of fibrinolysis (Doolittle, this volume).5,6 Both the rate of fibrinolysis and the structures of soluble derivatives are determined in part by the fibrin network structure itself. Furthermore, the activation of plasminogen by t-PA is accelerated by the conversion of fibrinogen to fibrin, and this reaction is also affected by the structure of the fibrin. For example, clots made of thin fibers have a decreased rate of conversion of plasminogen to plasmin by t-PA, and they generally are lysed more slowly than clots composed of thick fibers.7-9 Under other conditions, however, clots made of thin fibers may be lysed more rapidly.10 In addition, fibrin clots composed of abnormally thin fibers formed from certain dysfibrinogens display decreased plasminogen binding and a lower rate of fibrinolysis.11-13 Therefore, our increasing knowledge of various dysfibrinogenemias will aid our understanding of mechanisms of fibrinolysis (Matsuda, this volume).14,15 To account for these diverse observations and more fully understand the molecular basis of fibrinolysis, more knowledge of the physical changes in the fibrin matrix that precede solubilization is required. In this report, we summarize recent experiments utilizing transmission and scanning electron microscopy and confocal light microscopy to provide information about the structural changes occurring in polymerized fibrin during fibrinolysis. Many of the results of these experiments were unexpected and suggest some aspects of potential molecular mechanisms of fibrinolysis, which will also be described here.

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Fibrinogen Bastia (γ 318 Asp → Tyr) a Novel Abnormal Fibrinogen Characterized by Defective Fibrin Polymerization

Thrombosis and Haemostasis ◽

10.1055/s-0037-1614892 ◽

1999 ◽

Vol 82 (12) ◽

pp. 1639-1643 ◽

Cited By ~ 9

Author(s):

Karim Chabane Lounes ◽

Claudine Soria ◽

Antoine Valognes ◽

Marie France Turchini ◽

Jaap Koopman ◽

...

Keyword(s):

Calcium Ions ◽

Clinical Symptoms ◽

Degradation Products ◽

Base Substitution ◽

Chain Gene ◽

Fibrinogen Concentration ◽

Clotting Time ◽

Terminal Part ◽

Fibrin Polymerization ◽

Chain Sequence

SummaryA new congenital dysfibrinogen, Fibrinogen Bastia, was discovered in a 20-year-old woman with no clinical symptoms. The plasma thrombin-clotting time was severely prolonged. The functional plasma fibrinogen concentration was low (0.2 mg/ml), whereas the immunological concentration was normal (2.9 mg/ml). Purified fibrinogen Bastia displayed a markedly prolonged thrombin-clotting time related to a delayed thrombin-induced fibrin polymerization. Both the thrombin-clotting time and the fibrin polymerization were partially corrected by the addition of calcium ions. The anomaly of fibrinogen Bastia was found to be located in the γ-chain since by SDS-PAGE performed according to the method of Laemmli two γ-chains were detected, one normal and one with an apparently lower molecular weight. Furthermore, analysis of plasmin degradation products demonstrated that calcium ions only partially protect fibrinogen Bastia γ-chain against plasmin digestion, suggesting that the anomaly is located in the C-terminal part of the γ-chain. Sequence analysis of PCR-amplified genomic DNA fragments of the propositus demonstrated a single base substitution (G → T) in the exon VIII of the γ chain gene, resulting in the amino acid substitution 318 Asp (GAC) → Tyr (TAC). The PCR clones were recloned and 50% of them contained the mutation, indicating that the patient was heterozygous. These data indicate that residue Asp 318 is important for normal fibrin polymerization and the protective effect of calcium ions against plasmin degradation of the C-terminal part of the γ-chain.

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A Monoclonal Antibody-Based Enzyme Immunoassay for Fibrin Degradation Products in Plasma

Thrombosis and Haemostasis ◽

10.1055/s-0038-1642777 ◽

1988 ◽

Vol 59 (02) ◽

pp. 310-315 ◽

Cited By ~ 64

Author(s):

P W Koppert ◽

E Hoegee-de Nobel ◽

W Nieuwenhuizen

Keyword(s):

Enzyme Immunoassay ◽

Degradation Products ◽

Blood Clot ◽

Tissue Type ◽

Fibrin Degradation Products ◽

Type Plasminogen Activator ◽

Strong Positive Reaction ◽

Sandwich Type ◽

Capture Antibody

SummaryWe have developed a sandwich-type enzyme immunoassay (EIA) for the quantitation of fibrin degradation products (FbDP) in plasma with a time-to-result of only 45 minutes.* The assay is based on the combination of the specificities of two monoclonal antibodies (FDP-14 and DD-13), developed in our institute. FDP-14, the capture antibody, binds both fibrinogen degradation products (FbgDP) and FbDP, but does not react with the parent fibrin(ogen) molecules. It has its epitope in the E-domain of the fibrinogen molecule on the Bβ-chain between amino acids 54-118. Antibody DD-13 was raised using D-dimer as antigen and is used as a tagging antibody, conjugated with horse-radish peroxidase. A strong positive reaction is obtained with a whole blood clot lysate (lysis induced by tissue-type plasminogen activator) which is used as a standard. The EIA does virtually not detect FbgDP i. e. purified fragments X, Y, or FbgDP generated in vitro in plasma by streptokinase treatment. This indicates that the assay is specific for fibrin degradation products.We have successfully applied this assay to the plasma of patients with a variety of diseased states. In combination with the assay previously developed by us for FbgDP and for the total amount of FbgDP + FbDP (TDP) in plasma, we are now able to study the composition of TDP in patients plasma in terms of FbgDP and FbDP.

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