A little-known approach to toxicity testing--based on negative phototaxis of larval <u>Aedes aegypti</u>--was investigated as a contribution to the search for rapid methods applicable to the field of water pollution control. Zinc and copper were the toxicants tested. All tests were conducted with a standard "synthetic" dilution water. A mosquito colony was established to provide a uniform supply of test larvae. Preliminary tests were performed on the acute toxicity of zinc and copper against <u>A. aegypti</u> larvae, as well as tests on larval growth and development at various concentrations of the metals. For the photomigration toxicity tests, two juxtaposed troughs were used, one containing the test solution, the other a control. Third instar larvae migrated away from a six-watt fluorescent light for two minutes per run. This was repeated at intervals until 50% were unable to migrate 50 cm in 120 sec. Photographs were taken of the larval migrations. From the pictures an empirical criterion was derived (the 40-cm, 60-sec ET₅₀) through a series of graphical interpolations. All inactivation analyses were based on this criterion. From time-inactivation regression lines, exponential toxicity curves were obtained by interpolation. The curves were of an unusual shape, depicting the characteristic nature of the dosage-response. The sensitivity of the inactivation technique was comparable to that of the acute toxicity tests. However, inactivation was far quicker; depending on concentration, it occurred within one to five hours. By all methods used in this study, zinc and copper were judged to be slow-acting and of low overall toxicity. Copper was, however, consistently more toxic than zinc by at least one order of magnitude. The ET₅₀ in 10 ppm Cu⁺⁺ was 147 min.; in 10 ppm Zn⁺⁺, it was 209 min. Some possible improvements in technique were discussed. It was suggested that the photornigration approach to toxicity testing can be of definite practical use to biologists in water pollution control. / Master of Science

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2014-11-07T11:40:53Z No. of bitstreams: 2 Dissertação - Laurindo Camilo de Castro Júnior - 2008.pdf: 744212 bytes, checksum: 54bc98384ca53eb5c272a0d02e1d0e7f (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2014-11-07T12:13:47Z (GMT) No. of bitstreams: 2 Dissertação - Laurindo Camilo de Castro Júnior - 2008.pdf: 744212 bytes, checksum: 54bc98384ca53eb5c272a0d02e1d0e7f (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-11-07T12:13:47Z (GMT). No. of bitstreams: 2 Dissertação - Laurindo Camilo de Castro Júnior - 2008.pdf: 744212 bytes, checksum: 54bc98384ca53eb5c272a0d02e1d0e7f (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2008-09-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The control and combat culicines have presented difficuties related to the emergence of resistant mosquito populations, ostensibly occasioned by the use of current synthetic insecticides. This reality creates the necessity of looking for new substances insecticide and constant development of new formulations. Face to this situation, phytochemical studies have demonstrated that plants are an abundant source of new active principles. In this work, a quantitative and qualitative review was carried out, between the period of 1970 and 2010, looking for plants that had presented insecticidal effect on culicines, with importance to public health. There were found 174 botanical species, distributed in 56 families, with bigger concentration of species in the Lamiaceae (15 species), Fabaceae (12 species), Asteraceae (12 species), Cucurbitaceae (9 species) and Myrtaceae (9 species) families. The main insecticidal effects founded in the related articles were: larvicidal action, mosquitocidal action, growth inhibition and repellency effect. About the insecticide activity, the Copaifera reticulata and Piper nigrum were the plants that presented the larger potentials for Culicinae. The diterpenoide, acid 3-ß-acetoxylabdan-8(17)-13-dien-15-oico, isolated of C. reticulata, it was more active substance against Aedes aegypti and Culex quinquefasciatus, following by the substances isolated of P. nigrum: piperina, pellitorine, piperecida, guineensina and retrofractamida that active against Ae. aegypti, Ae. togoi, Cx. quinquefasciatus and Cx. pipiens pallens. / O controle e o combate de culicíneos têm apresentado dificuldades relacionadas ao surgimento de populações de mosquitos resistentes, ocasionadas pelo emprego ostensivo dos atuais inseticidas sintéticos. Na busca de alternativas de baixa toxicidade e menor impacto ambiental, vários investigadores têm estudado os produtos de origem botânica na procura de novas substâncias inseticidas. Frente a esta situação, estudos fitoquímicos têm demonstrado que as plantas são fontes abundantes de novos princípios ativos. Neste contexto, uma revisão da literatura pertinente a esse assunto foi realizada entre os períodos de 1970 a 2010, sobre plantas que apresentaram efeito toxicológico sobre culicíneos de importância para a saúde pública. Foram encontradas 174 espécies de plantas, distribuídas em 56 famílias, com maior concentração de espécies nas famílias Lamiaceae (15 espécies), Fabaceae (12 espécies), Asteraceae (12 espécies), Cucurbitaceae (9 espécies) e Myrtaceae (9 espécies). Os principais efeitos verificados foram ações larvicida, adulticida, efeito inibidor do crescimento e repelência. Com relação à atividade inseticida, a Copaifera reticulata e Piper nigrum, foram as plantas que apresentaram potenciais maiores para culicíneos. O diterpenoide, ácido 3- - acetoxylabdan-8(17)-13-dien-15-óico, isolado de C. reticulata, foi a substância mais ativa contra Aedes aegypti e Culex quinquefasciatus, seguidas das substâncias isoladas do óleo de P. nigrum: piperina, pellitorine, pipericida, guineensina e retrofractamida que se mostraram ativas para Aedes aegypti, Ae. togoi, Cx. quinquefasciatus e Cx. pipiens pallens.