RESUMEN
Human papillomavirus type 16 (HPV16) is a major agent in cervical cancer etiology. Its early proteins are responsible for virus persistence, replication and initiation of neoplastic disease. In the present study we describe a use of baculovirus-insect cell expression system for production and study of HPV16 E2 and E4 proteins. The E2 protein binds specifically to viral DNA and E4 protein shows characteristic cytopathic effects on cells.
Asunto(s)
Baculoviridae/genética , Proteínas de Unión al ADN , Proteínas Oncogénicas Virales/biosíntesis , Papillomaviridae/metabolismo , Animales , Autorradiografía , Línea Celular , Núcleo Celular/genética , Electroforesis en Gel de Poliacrilamida , Humanos , Insectos , Proteínas Oncogénicas Virales/genética , Plásmidos/genéticaRESUMEN
The copper(II) complexing ability and the biological activity of beta-casomorphin-7 tetrazole analogues have been investigated. Potentiometric and spectroscopic (UV-Vis, CD and EPR) studies have been used to establish the thermodynamic stability, speciation and structure of Cu(II) complexes with YP-psi(CN4)-FPGPI-NH2 (1), YPF-psi(CN4)-AGPI-NH2 (2) and YPFP-psi(CN4)-GPI-NH2 (3). Comparison of the binding ability of the tetrazole analogues reveals that the most effective ligand for copper(II) is YPF-psi(CN4)-AGPI-NH2. The effectiveness of this ligand comes from its particular conformation suited for the Cu(II) 2N co-ordination mode in the physiological pH region. The ability of casomorphin tetrazole analogues to activate rat mast cells to histamine release in vitro in the presence of copper(II) has been studied.
Asunto(s)
Endorfinas/farmacología , Narcóticos/química , Oligopéptidos/síntesis química , Oligopéptidos/farmacología , Péptidos/metabolismo , Tetrazoles/química , Tetrazoles/síntesis química , Tetrazoles/farmacología , Animales , Dicroismo Circular , Cobre/metabolismo , Espectroscopía de Resonancia por Spin del Electrón , Endorfinas/química , Histamina/biosíntesis , Concentración de Iones de Hidrógeno , Ligandos , Mastocitos/efectos de los fármacos , Mastocitos/metabolismo , Modelos Químicos , Péptidos/química , Unión Proteica , Conformación Proteica , Estructura Secundaria de Proteína , Ratas , Espectrofotometría , Termodinámica , Rayos UltravioletaRESUMEN
It is well known that in some conditions bacteria of physiological flora of gastrointestinal tract may become pathogenic. Each complaint which causes injury of gastrointestinal wall integrity permits bacteria to penetrate the tissues and affect the tissue cells. Since mast cells represent one of very important and numerous cellular elements of the gastrointestinal tract walls, bacteria can exert the effects on them. Therefore, the aim of our study was to examine the influence of four strains of intestinal mucosa-associated bacteria--Bacteroides thetaiotaomicron, Bacteroides fragilis, Bifidobacterium adolescentis and Escherichia coli on the mast cell reactivity. Our experiments were performed in vitro on isolated rat peritoneal mast cells and the reactivity of these cells was estimated on the basis of histamine release. We used the suspensions of whole bacteria, killed by heating at 65 degrees C. We have noticed that the magnitude of bacteria-induced histamine release from mast cells was very low (up to 6.0%) when compared with histamine release induced with Con A, compound 48/80 and TNF-alpha. However, all studied bacteria changed the reactivity of mast cells in anaphylactic (with ConA) and anaphylactoid (with compound 48/80) reactions. After 40 min preincubation with B. thetaioataomicron, B. fragilis, B. adolescentis or E. coli ConA-induced histamine release was diminished up to 25%, 71%, 58% and and 68% of maximal histamine release, respectively. Preincubation of rat mast cells with B. thetaioataomicron, B. fragilis, B. adolescentis or E. coli also changed their reactivity in anaphylactoid reaction with compound 48/80 (histamine release was diminished up to 70%, 63%, 63% and 60%, respectively).
RESUMEN
Nowadays there is growing evidence that some cytokines regulate biological functions of the mature mast cells. Therefore, we have studied whether TNF-alpha, the cytokine of multifunctional activities, could directly stimulate rat peritoneal mast cells to histamine secretion and whether it could modulate rat mast cell reactivity in anaphylactic (with ConA) and anaphylactoid (with compound 48/80) reactions. We have established that rat recombinant TNF-alpha does not activate rat mast cells to histamine release. However, TNF-alpha-treatment causes the decrease of spontaneous histamine release up to 85% (TNF-alpha concentration: 2 x 10(-9) M). Pretreatment of mast cells with TNF-alpha inhibits ConA-stimulate release of histamine with the percent release decreasing up to 33.7% of the control value (TNF-alpha concentration: 5 x 10(-9) M) and this decrease is statistically significant. Pretreatment of mast cells with TNF-alpha reduces compound 48/80-dependent histamine release as well and the percent release of histamine fell to 64.7% of the control value. We have concluded that TNF-alpha may play a significant role in regulation of mast cell secretory activity.
Asunto(s)
Liberación de Histamina/efectos de los fármacos , Mastocitos/inmunología , Factor de Necrosis Tumoral alfa/farmacología , Anafilaxia/inducido químicamente , Anafilaxia/inmunología , Animales , Concanavalina A/farmacología , Femenino , Ratas , Ratas Wistar , Proteínas Recombinantes/farmacologíaRESUMEN
Recent studies have led to a rapid expansion of knowledge concerning the structure and biology of mast cells neutral proteinases. Therefore, in this paper tryptases, chymases, carboxypeptidases and cathepsin G have been described and their biological roles have been discussed.