Platelets provide robustness of spatial blood coagulation to the variation of initial conditions.

Activated platelets provide phospholipid surface and secrete coagulation factors, enhancing blood clotting. We investigated the role of platelets in the regulation of blood coagulation spatial dynamics. We activated blood clotting with tissue factor-bearing (TF) surface in platelet-rich plasma (PRP) or platelet-free plasma (PFP).

Hysteresis-like binding of coagulation factors X/Xa to procoagulant activated platelets and phospholipids results from multistep association and membrane-dependent multimerization.

Binding of coagulation factors X (fX) and Xa (fXa) to activated platelets is required for the formation of membrane-dependent enzymatic complexes of intrinsic tenase and prothrombinase. We carried out an in-depth characterization of fX/fXa binding to phospholipids and gel-filtered, thrombin-activated platelets. Flow cytometry, surface plasmon resonance, and computational modeling were used to investigate interactions of fX/fXa with the membranes.

Platelet surface-associated activation and secretion-mediated inhibition of coagulation factor XII.

Coagulation factor XII (fXII) is important for arterial thrombosis, but its physiological activation mechanisms are unclear. In this study, we elucidated the role of platelets and platelet-derived material in fXII activation. FXII activation was only observed upon potent platelet stimulation (with thrombin, collagen-related peptide, or calcium ionophore, but not ADP) accompanied by phosphatidylserine exposure and was localised to the platelet surface.

A nascent proteome study combining click chemistry with 2DE.

To investigate the dynamic cellular response to a condition change, selective labeling of the nascent proteome is necessary. Here, we report a method combining click chemistry protein labeling with 2D DIGE. To test the relevance of the method, we compared nascent proteomes of actively growing bacterial cells with that of cells exposed to protein synthesis inhibitor, erythromycin.

Non-stressful death of 23S rRNA mutant G2061C defective in puromycin reaction.

Catalysis of peptide bond formation in the peptidyl transferase center is a major enzymatic activity of the ribosome. Mutations limiting peptidyl transferase activity are mostly lethal. However, cellular processes triggered by peptidyl transferase deficiency in the bacterial cell are largely unknown.

Core proteome of the minimal cell: comparative proteomics of three mollicute species.

Mollicutes (mycoplasmas) have been recognized as highly evolved prokaryotes with an extremely small genome size and very limited coding capacity. Thus, they may serve as a model of a 'minimal cell': a cell with the lowest possible number of genes yet capable of autonomous self-replication. We present the results of a comparative analysis of proteomes of three mycoplasma species: A.

The acylation state of surface lipoproteins of mollicute Acholeplasma laidlawii.

Acylation of the N-terminal Cys residue is an essential, ubiquitous, and uniquely bacterial posttranslational modification that allows anchoring of proteins to the lipid membrane. In gram-negative bacteria, acylation proceeds through three sequential steps requiring lipoprotein diacylglyceryltransferase, lipoprotein signal peptidase, and finally lipoprotein N-acyltransferase. The apparent lack of genes coding for recognizable homologs of lipoprotein N-acyltransferase in gram-positive bacteria and Mollicutes suggests that the final step of the protein acylation process may be absent in these organisms.

The role of intracellular glutathione in the progression of Chlamydia trachomatis infection.

The productive internalization in the host cell of Chlamydia trachomatis elementary bodies and their infectivity depends on the degree of reduction of disulfide bonds in the outer envelope of the elementary body. We have hypothesized that the reducing agent may be intracellular glutathione (GSH). Three approaches were used to modulate the intracellular GSH concentration: (1) treatment of cells with buthionine sulfoximine, which causes irreversible inhibition of GSH biosynthesis; (2) hydrogen peroxide-induced oxidation of GSH by intracellular glutathione peroxidases; and (3) treatment of cells with N-acetyl-l-cysteine (NAC), a precursor of glutathione.

Functional divergence of Helicobacter pylori related to early gastric cancer.

Helicobacter pylori is an extra macro- and microdiverse bacterial species, but where and when diversity arises is not well-understood. To test whether a new environment accelerates H. pylori genetic changes for quick adaptation, we have examined the genetic and phenotypic changes in H.

Importance of Protocol Immunization in Epitope Selectivity of Monoclonal Antibodies Interacting with Binding Subunit of Viscumin.

The application of two immunization protocols and two screening systems has allowed to produce five hybridomas mlb5, mlb6, mlb7, mlb9 and Mbch1, secreting mAbs against different sites of viscumin B-subunit. On the base of mlb9 and Mbch1 hybridomas, the test-system has been developed, able to detect up to 5 ng/ml of viscumin and up to 1 ng/ml of its B-chain. Produced hybridomas and monoclonal antibodies will be used for the studies of intracellular transport of plant toxins.