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Protein Reaction (protein + reaction)
Selected AbstractsUltrastructural and histochemical study on gills and skin of the Senegal sole, Solea senegalensisJOURNAL OF APPLIED ICHTHYOLOGY, Issue 6 2004J. M. Arellano Summary This study was undertaken to identify the normal ultrastructural features of gills and skin of the Senegal sole, Solea senegalensis, for a comparative measure to morphological alterations caused by environmental stressors such as reduced water quality and diseases. In the Senegal sole skin, four morphologically distinct layers were identified: cuticle, epidermis, dermis and hypodermis. The epidermis was composed of stratified epithelium containing three cellular layers: the outermost or mucosa layer, the middle or fusiform layer and the stratum germinativum or the basal layer. In the mucosa, two mucous cell types were differentiated: type A cells containing several round vesicles of different electron density and type B cells containing mucosomes of uniform electron density. Senegal sole have five pairs of gill arches, each containing two rows of well-developed and compactly organized primary filaments and secondary lamellae. Fingerprint-like microridges were observed on the surface of epithelial cells. The branchial lamellae epithelium consisted of different cell types: pavement, mucous and chloride. Between the chloride cells and the larger pavement cells, accessory cells were observed. Complexes of tight junctions and desmosomes were frequently observed between adjacent chloride and epithelial cells. Neutral mucosubstances and/or glycoconjugates were observed in the epidermis, dermis and hypodermis of S. senegalensis skin. Proteins rich in different amino acids, such as arginine and cysteine, reacted negatively or weakly positive in the epidermis, dermis and hypodermis. In gills, some mucous cells responded weakly positive to periodic acid-Schiff (PAS) reaction but were strongly stained with Alcian Blue at pH 0.5, 1 and 2.5. When Alcian Blue pH 2.5,PAS reaction was performed, most mucous cells were stained blue (carboxylated mucins) and some mucocytes stained purple, indicating a combination of neutral and acid mucins. Proteins rich in cysteine-bound sulphydryl (-SH-) and cystine disulphide (-S-S-) groups were strongly detected in branchial and epidermal mucous cells, whereas lysine, tyrosine and arginine containing proteins showed very weak staining in both epidermal and branchial mucous cells. Protein reactions were strongly positive in the pillar cells, except for those rich in tryptophan, whereas the branchial cartilaginous tissue did not show an important reaction. The performed lipid reactions were negative in goblet and chloride cells. It is concluded from this study that ultrastructural and cytohistochemical features of the Senegal sole skin and gills may serve as control structures in both natural and aquaculture systems to monitor or detect environmental stress responses at the histological level. [source] Protein thermal stability and phospholipid,protein interaction investigated by capillary isoelectric focusing with whole column imaging detectionJOURNAL OF SEPARATION SCIENCE, JSS, Issue 7 2006Tao Bo Abstract CIEF with whole column imaging detection (WCID) is an attractive technique for studying protein reaction and protein,ligand interaction due to its fast separation, simple operation, and high efficiency. In this study, two interesting applications by the CIEF-WCID were developed, involving the study of protein thermal stability and phospholipid,protein interaction. Four proteins (,-lactoglobulin B, trypsin inhibitor, phosphorylase b, and trypsinogen) with different pI, and two types of phospholipids, including phosphatidylcholine (PC) and phosphatidylserine (PS), were used for this purpose. First, the altered CIEF profiles of four proteins were exhibited due to conformational changes resulting from protein denaturation induced by a high incubation temperature at 60°C. It was demonstrated that the addition of a zwitterionic phospholipid (PC) played a crucial role in the thermal stability of targeted proteins, especially for trypsin inhibitor whose thermal stability was promoted with the addition of the PC vesicles at 60°C. Second, the zwitterionic (PC) and acidic (PS) phospholipids displayed completely different interactions with the proteins. The addition of PS vesicles modified the zwitterionic phospholipids to carry negative charges, which correspondingly changed the interaction between the phospholipid and the protein. Our study demonstrates that the CIEF-WCID is a powerful approach to study protein reaction and protein,ligand interaction with high efficiency, high selectivity, and fast separation. [source] Astroblastoma with unusual signet-ring-like cell components: A case report and literature reviewNEUROPATHOLOGY, Issue 3 2002Yasuo Sugita We report a case of astroblastoma with unusual signet-ring-like cell components. A 33-year-old-woman presented with occasional partial seizures of the face. Radiological studies revealed an enhanced frontal mass lesion. At surgery, a gray, soft, well-circumscribed mass was seen and shelled out. Histologically, the tumor showed a perivascular arrangement and papillary-like patterns with compact cellularity. The tumor cells radiating from the hyalinized vessels showed broader, shorter, less tapered processes. A part of each tumor cell displayed prominent islands of signet-ring-like cells. Glial fibrillary acidic protein reaction revealed strongly positive staining of tumor cells and signet-ring-like cells. Eight years after the operation the patient remains well with no tumor recurrence. It remains to be determined whether, in this astroblastoma, the unusual signet-ring-like cell components were related to benign biological characteristics or to the tumor's low-grade form with incidental signet-ring-like cell appearance. [source] Binding interactions between peptides and proteins of the class II Major Histocompatibility ComplexMEDICINAL RESEARCH REVIEWS, Issue 2 2002Benjamin J. McFarland Abstract The activation of helper T cells by peptides bound to proteins of the class II Major Histocompatibility Complex (MHC II) is pivotal to the initiation of an immune response. The primary functional requirement imposed on MHC II proteins is the ability to efficiently bind thousands of different peptides. Structurally, this is reflected in a unique architecture of binding interactions. The peptide is bound in an extended conformation within a groove on the membrane distal surface of the protein that is lined with several pockets that can accommodate peptide side-chains. Conserved MHC II protein residues also form hydrogen bonds along the length of the peptide main-chain. Here we review recent advances in the study of peptide-MHC II protein reactions that have led to an enhanced understanding of binding energetics. These results demonstrate that peptide-MHC II protein complexes achieve high affinity binding from the array of hydrogen bonds that are energetically segregated from the pocket interactions, which can then add to an intrinsic hydrogen bond-mediated affinity. Thus, MHC II proteins are unlike antibodies, which utilize cooperativity among binding interactions to achieve high affinity and specificity. The significance of these observations is discussed within the context of possible mechanisms for the HLA-DM protein that regulates peptide presentation in vivo and the design of non-peptide molecules that can bind MHC II proteins and act as vaccines or immune modulators. © 2002 John Wiley & Sons, Inc. Med Res Rev, 22, No. 2, 168,203, 2002; DOI 10.1002/med.10006 [source] Time-resolved structural studies of protein reaction dynamics: a smorgasbord of X-ray approachesACTA CRYSTALLOGRAPHICA SECTION A, Issue 2 2010Sebastian Westenhoff Proteins undergo conformational changes during their biological function. As such, a high-resolution structure of a protein's resting conformation provides a starting point for elucidating its reaction mechanism, but provides no direct information concerning the protein's conformational dynamics. Several X-ray methods have been developed to elucidate those conformational changes that occur during a protein's reaction, including time-resolved Laue diffraction and intermediate trapping studies on three-dimensional protein crystals, and time-resolved wide-angle X-ray scattering and X-ray absorption studies on proteins in the solution phase. This review emphasizes the scope and limitations of these complementary experimental approaches when seeking to understand protein conformational dynamics. These methods are illustrated using a limited set of examples including myoglobin and haemoglobin in complex with carbon monoxide, the simple light-driven proton pump bacteriorhodopsin, and the superoxide scavenger superoxide reductase. In conclusion, likely future developments of these methods at synchrotron X-ray sources and the potential impact of emerging X-ray free-electron laser facilities are speculated upon. [source] | ||||||||||