We have shown that electroporation of plasmid carrying extracellular and transmembrane domains (EC-TM plasmid) encoded by the rat neu oncogene triggers a protective immune response toward rat ...p185(neu)-positive tumors in both wild-type BALB/c mice and cancer-prone rat neu-transgenic BALB-neuT mice. To identify the critical fragments that confer this protective immunity, mice were electroporated with plasmids encoding the TM domain associated with decreasing fragments of the EC domain and the antitumor protection afforded, the titer of antibody, and cytotoxic T lymphocyte (CTL) activity elicited to Neu protein were evaluated. Plasmids encoding EC fragments shortened by 70 (EC1-TM plasmid), 150 (EC2-TM), 230 (EC3-TM), 310 (EC4-TM), and 390 (EC5-TM) NH(2)-terminal residues afforded effective protection. Plasmids encoding shorter truncated proteins were ineffective. When the immunogenic protein was retained in the cytoplasm (EC1-TM, EC2-TM, and EC5-TM), only a CTL response was elicited, whereas when it was also expressed on the membrane (EC4-TM) both CTLs and antibodies were induced. EC4-TM encoding a truncated protein with an EC portion of only 344 amino acids conferred protection on both BALB/c and BALB-neuT mice comparable to that of EC-TM.
Aflatoxins are highly hazardous contaminants of common food and feed. Aflatoxin B
1 in particular, the most predominant among aflatoxins, was thoroughly demonstrated to be highly toxic, mutagenic, ...teratogenic and carcinogenic in many animal species. Besides its established targets and effects, this work investigates on the possible direct interaction between aflatoxin B
1 and three major serine proteases, namely elastase, thrombin and trypsin.
These proteases belongs to a class of structurally and functionally related proteins pivotal in both direct and indirect regulation of a number of cellular events. Additionally, several pathological processes, including cancer, inflammatory processes and thrombosis, rely upon the subtle equilibrium between these enzymes and their potential modulators: in fact, their misregulation, caused by foreign molecules, could facilitate (or be the cause for) the occurrence of these pathologies.
Our results provide the evidence for a reversible binding between AFB
1 and these enzymes, likely to have profound implications in the manifestation of aflatoxicosis. Precisely, the toxin behaved as a moderate competitive inhibitor toward the enzymatic activity of the serine proteases in the low micromolar range.
The structure–function relationships occurring on the bovine thymus 20S proteasome, which exhibits the features of an immunoproteasome, have been studied. The investigation has been performed, ...essentially, using a fluorimetric approach, taking advantage either of the sensitivity of the complex to sodium dodecil sulfate and chaotropic agents (urea and guanidine hydrochloride) or of the presence, on the molecule, of a high number of tryptophan residues. The results obtained indicate that the perturbation or the oxidation of these residues affect the catalytic events taking place on the thymus proteasome and that the functional effects determined by SDS and chaotropic agents most likely occur through a series of progressive structural modifications leading to an inactive molecule. The presence of structural intermediates in the proteasome inactivation process suggests that thymus proteasome is a molecule characterized, at the same time, by structural flexibility (modulation of active sites) and structural stability (maintaining of the quaternary structure) in agreement with its crucial role in the cell life cycle.
Aflatoxins are highly hazardous contaminants of common food and feed. Aflatoxin B1 in particular, the most predominant among aflatoxins, was thoroughly demonstrated to be highly toxic, mutagenic, ...teratogenic and carcinogenic in many animal species. Besides its established targets and effects, this work investigates on the possible direct interaction between aflatoxin B1 and three major serine proteases, namely elastase, thrombin and trypsin. These proteases belongs to a class of structurally and functionally related proteins pivotal in both direct and indirect regulation of a number of cellular events. Additionally, several pathological processes, including cancer, inflammatory processes and thrombosis, rely upon the subtle equilibrium between these enzymes and their potential modulators: in fact, their misregulation, caused by foreign molecules, could facilitate (or be the cause for) the occurrence of these pathologies. Our results provide the evidence for a reversible binding between AFB1 and these enzymes, likely to have profound implications in the manifestation of aflatoxicosis. Precisely, the toxin behaved as a moderate competitive inhibitor toward the enzymatic activity of the serine proteases in the low micromolar range.
Summary Temporomandibular joint (TMJ) ankylosis is a pathological condition characterized by articular bony or fibrous tissue fusion. TMJ ankylosis developing during childhood can lead to growth ...complications because of the loss of mandibular function. Hard and soft autogenous tissue grafting has been used for TMJ reconstruction in the growing patient. However, in cases where autogenous tissue grafts fail either due to unpredictable growth or ankylosis, total alloplastic temporomandibular joint replacement (TMJ TJR) can provide a viable option. The case of a 7-year old female suffering from recurrent bilateral TMJ ankylosis resulting from birth trauma, and with concomitant obstructive sleep apnea syndrome (OSAS) is presented. Due to prior surgical and autogenous graft failures, the decision was made to complete her joint reconstructions utilizing patient-fitted TMJ prostheses. Questions have been raised about the longevity of TMJ TJR devices as well as their lack of growth potential, but children with TMJ ankylosis do not have condyle-related growth potential and that replacing failed autogenous tissue graft material with more autogenous tissue will result in the same adverse outcomes. Therefore, in growing patients with recurrent TMJ ankylosis and/or failed autogenous tissue grafts, there may be a role for TMJ TJR.
The thermodynamic parameters affecting protein-protein multimeric self-assembly equilibria of the histone-like protein H-NS were quantified by "large zone" gel-permeation chromatography. The ...abundance of the different association states (monomer, dimer, and tetramer) were found to be strictly dependent on the monomeric concentration and affected by physical (temperature) and chemical (cations) parameters. On the basis of the results obtained in this study and the available structural information concerning this protein, a mechanism is proposed to explain the association behavior also in relation to the functional properties of the protein.
The 20S proteasome is responsible for the degradation of protein substrates implicated in the onset and progression of neurodegenerative disorders, such as α-synuclein and tau protein. Here we show ...that the 20S proteasome isolated from bovine brain directly hydrolyzes, in vitro, the dihydrofolate reductase (DHFR), demonstrated to be involved in the pathogenesis of neurodegenerative diseases. Furthermore, the DHFR susceptibility to proteolysis is enhanced by oxidative conditions induced by peroxynitrite, mimicking the oxidative environment typical of these disorders. The results obtained suggest that the folate metabolism may be impaired by an increased degradation of DHFR, mediated by the 20S proteasome.
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