No description available.

No description available.

No description available.

No description available.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 54-58). Also available via the Internet.

No description available.

This research was undertaken in order to design techniques and processes that enable the manufacture of effective antivenoms. To prepare a broad specificity anti venom for European vipers from chicken yolk it was first necessary to develop a simple effective method to extract avian immunoglobulin (lgY). A specific fluoroimmunoassay was developed to monitor IgY recovery and serum IgY levels in immunised hens. The most promising extraction methods from the literature were compared using a triglyceride kit to monitor lipoprotein removed and SDS-PAGE and ELISA to monitor purity and activity respectively. Caprylic acid followed by ammonium sulphate proved the best method. Unfortunately only low levels of specific IgY were achieved and it was necessary to include an affinity purification step to demonstrate their effectiveness in an EDso test. Pepsin, papain and trypsin all produced Fab' fragments from IgY but only pepsin digested the resultant Fc fragments. Pepsin could also digest other proteins in egg yolk, thereby avoiding the need to salt fractionate IgY prior to its digestion with a consequent improvement in the recovery of Fab'. A small scale affinity purification (SSAP) assay was developed, characterised and used to determine specific antibody levels in ovine antisera. Small doses (l5IAg) of venom produced significant specific levels but larger doses produced a better response and were used to produce anti venom. Binding studies with SSAP demonstrated a high concentration of specific antibodies in V.latastei antisera that bind to components in the venoms of other European vipers. A specific ovine F(ab')2-based V.latastei antivenom approximately twice as potent as the anti venom used currently in Spain was prepared from the ovine antisera. Evidence is presented that SSAP should supersede manual ELISA for assessing specific antibody levels in antisera. No major gain in recovery and purity resulted from processing whole blood rather than serum for preparing antivenom.

Bacterial transformation is defined as a mechanism of genetic exchange whereby a population of bacteria can obtain genetic informa-tion as a result of cellular uptake and integration of extracellular deoxyribonucleic acid released from other bacteria by natural or in-duced lysis. In order for a transformable strain of bacteria to take up DNA and to undergo transformation, the cells must be in a physiolog-ical state called competence. A cell is referred to as competent if it has the ability to bind extracellular DNA irreversibly and subsequently to integrate and express the DNA.

Os envenenamentos por aranhas das espécies L. laeta, L. intermedia e L. gaucho, podem causar dermonecrose e efeitos sistêmicos. O principal componente tóxico do veneno destas apresenta atividade de esfingomielinase D (SMase D). O objetivo do presente estudo foi comparar o potencial neutralizante do novo soro anti-SMases D recombinantes e do soro anti-Aracnídico contra os efeitos tóxicos dos três venenos. A análise por \"Western blot\" revelou que o anti-Aracnídico reconheceu a maioria dos componentes presentes nos três venenos, enquanto o anti-SMases D reconheceu apenas os componentes de 30-35 kDa, correspondente às isoformas nativas de SMases D. Por ELISA, verificou-se que o soro anti-SMases D contém títulos superiores de IgGT, IgGa, b e c e. Nos testes de soroneutralização, o soro anti-SMases D tem melhor atividade inibitória sobre as atividades dermonecrótica, hemolítica e esfingomielinásica dos venenos de L. intermedia e L. laeta. Para o veneno de L. gaucho, o soro anti-Aracnídico teve resultados similares ou melhores. Embora o soro anti-SMases D apresente um significante potencial neutralizante é necessária a inclusão da SMase D do veneno de L. gaucho para a obtenção de um anti-soro eficaz contra estes venenos. / Envenomation by spiders of species L. laeta, L. intermedia and L. gaucho causes local dermonecrosis and systemic effects. The main toxic component is endowed with sphingomyelinase D (SMase D) activity. The aim of this study was to compare the neutralization potentials of the anti-SMases D and the anti-arachnidic sera, against the toxic effects of venoms of these three species. The analysis by western blot has revealed that the anti-arachnidic serum was able to recognize the majority of the components present on the venoms of the three species, but anti-SMases D has recognized only components of 30-35 kDa, which corresponds to natives SMases D. By ELISA, it has been determined that the anti-SMases D serum contains higher titres of IgGT, IgGa, b and c than the anti-arachnidic serum. Serum neutralization tests have showed that the anti-SMases D serum has better inhibitory shingomyelinasic, dermonecrotic and haemolytic activities of the venoms from L. intermedia and L. laeta. For L. gaucho venom, the results have been similar or better than the anti-arachnidic serum. Although the anti-SMases D serum shows a significant neutralization potential, it is necessary the inclusion of a SMase D from L. gaucho venom, to obtain a efficient antiserum against this venom.

Os envenenamentos por aranhas das espécies L. laeta, L. intermedia e L. gaucho, podem causar dermonecrose e efeitos sistêmicos. O principal componente tóxico do veneno destas apresenta atividade de esfingomielinase D (SMase D). O objetivo do presente estudo foi comparar o potencial neutralizante do novo soro anti-SMases D recombinantes e do soro anti-Aracnídico contra os efeitos tóxicos dos três venenos. A análise por \"Western blot\" revelou que o anti-Aracnídico reconheceu a maioria dos componentes presentes nos três venenos, enquanto o anti-SMases D reconheceu apenas os componentes de 30-35 kDa, correspondente às isoformas nativas de SMases D. Por ELISA, verificou-se que o soro anti-SMases D contém títulos superiores de IgGT, IgGa, b e c e. Nos testes de soroneutralização, o soro anti-SMases D tem melhor atividade inibitória sobre as atividades dermonecrótica, hemolítica e esfingomielinásica dos venenos de L. intermedia e L. laeta. Para o veneno de L. gaucho, o soro anti-Aracnídico teve resultados similares ou melhores. Embora o soro anti-SMases D apresente um significante potencial neutralizante é necessária a inclusão da SMase D do veneno de L. gaucho para a obtenção de um anti-soro eficaz contra estes venenos. / Envenomation by spiders of species L. laeta, L. intermedia and L. gaucho causes local dermonecrosis and systemic effects. The main toxic component is endowed with sphingomyelinase D (SMase D) activity. The aim of this study was to compare the neutralization potentials of the anti-SMases D and the anti-arachnidic sera, against the toxic effects of venoms of these three species. The analysis by western blot has revealed that the anti-arachnidic serum was able to recognize the majority of the components present on the venoms of the three species, but anti-SMases D has recognized only components of 30-35 kDa, which corresponds to natives SMases D. By ELISA, it has been determined that the anti-SMases D serum contains higher titres of IgGT, IgGa, b and c than the anti-arachnidic serum. Serum neutralization tests have showed that the anti-SMases D serum has better inhibitory shingomyelinasic, dermonecrotic and haemolytic activities of the venoms from L. intermedia and L. laeta. For L. gaucho venom, the results have been similar or better than the anti-arachnidic serum. Although the anti-SMases D serum shows a significant neutralization potential, it is necessary the inclusion of a SMase D from L. gaucho venom, to obtain a efficient antiserum against this venom.