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Previous issue date: 2006-02-24 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Biological control of the tick Boophilus microplus with Metarhizium anisopliae and
Beauveria bassiana has been evaluated by several researchers. The selection of
specimens resistant to chemical products is a mechanism used by arthropods for
survival and maintenance in the environment. It is already known how fungi penetrate
the host and their pathogenic potential at different phases of their biological cycle,
however, ticks immune response against these agents need more detailed studies. The
present work had as objectives: to identify and quantify the cellular types involved in
the cellular response of B. microplus inoculated with entomopathogenic (M. anisopliae
and B. bassiana) and non-entomopathogenic fungi (Penicillium corylophilum and
Fusarium oxysporum). In this study 60 engorged females of B. microplus were used,
representing six treatment groups with 10 specimens each. Ticks were inoculated with
aqueous suspension of conidia. There were two control groups: in the first one ticks
were inoculated with Tween 80 0,1% aqueous solution (negative control), in the second
one ticks were not inoculated (testimony group). Fungi suspension or Tween 80 solution
were applied in the back part of the idiosoma of the tick. The hemolinfa samples were
collected during the whole period of life of the specimens, beginning 24 hours after
inoculation. The haemolymph samples were fixed in methanol and stained with Giemsa.
In all studied periods, cells like pro-hemocytes, plasmatocytes, granulocytes,
spherulocytes and oenocytoids were observed in the specimens of all groups. Prohemocytes,
plasmatocytes and spherulocytes were the most numerous cells observed in
the hemolinfa. Hemocytes were absent in the group inoculated with B. bassiana 72
hours after inoculation. After this period, specimens inoculated with entomopathogenic
fungi were dead. The absence of cells suggests the immune-suppressor effect of the
fungi on this tick species. It was not observed when ticks were treated with M.
anisopliae due to accentuated mortality caused by this fungus species. The nonentomopathogenic
fungi did not affect the life cycle of this tick, being quickly
eliminated of the organism. It was suggested based on the absence of conidia during
sampling. / O controle biol?gico do carrapato Boophilus microplus com a utiliza??o de Metarhizium
anisopliae e Beauveria bassiana tem sido avaliado por diversos pesquisadores. A
sele??o de cepas resistentes ? um mecanismo adotado pelos artr?podes para
sobreviv?ncia da esp?cie e sua manuten??o no ambiente. Apesar de estar esclarecida a
forma como o fungo penetra no hospedeiro e comprovada sua patogenicidade sobre
diferentes fases de seu ciclo biol?gico, a sua resposta imune frente a estes agentes
agressores necessita de maiores estudos. O presente trabalho teve como objetivo:
identificar e quantificar os tipos celulares envolvidos na resposta imune celular de B.
microplus inoculados com fungos entomopatog?nicos n?o entomopatog?nicos. Na
experimenta??o foram utilizados 60 f?meas ingurgitadas de Boophilus microplus,
representando seis tratamentos cada um contendo 10 esp?cimes. Para os grupos
inoculados com fungos entomopatog?nicos foi utilizada a suspens?o aquosa dos fungos
Metarhizium anisopliae (isolado Ma 959) e Beauveria bassiana (isolado Bb 986). Nos
tratamentos com fungos n?o entomopatog?nicos, Penicillium corylophilum e Fusarium
oxysporum, foram formados ainda um grupo testemunha (n?o recebeu inocula??o) e um
grupo inoculado com solu??o de tween 80 a 0,1% em ?gua destilada est?ril, considerado
controle negativo. Nos grupos dos tratamentos com suspens?o f?ngica ou solu??o a
inocula??o foi feita na regi?o posterior do idiossoma do carrapato. As coletas de
hemolinfa foram realizadas durante todo o per?odo de vida dos esp?cimes, tendo inicio
24 horas ap?s inocula??o. As amostras de hemolinfa foram fixadas com metanol e
coradas com Giemsa. Em todos os per?odos estudados, tanto nos esp?cimes inoculados
com fungos como nos controles, foram observados pr?-hem?citos, plasmat?citos,
granul?citos, esferul?citos e oenocit?ides. Pr?-hem?citos, plasmat?citos e esferul?citos
foram ?s c?lulas mais numerosas na hemolinfa. Foi observada a aus?ncia de hem?citos
no grupo inoculado com B. bassiana 72 horas ap?s a inocula??o, como tamb?m a morte
dos esp?cimes inoculados com fungos entomopatog?nicos a partir deste per?odo. A
aus?ncia de c?lulas evid?ncia o efeito imunossupressor do fungo sobre os carrapatos
estudados. Caracter?stica n?o observada para Metarhizium anisopliae, mesmo tendo
provocado acentuada mortalidade dos carrapatos. Os fungos n?o entomopatog?nicos
n?o afetaram de forma significativa o ciclo de vida destes carrapatos, sendo rapidamente
eliminados do organismo.
| Identifer | oai:union.ndltd.org:IBICT/oai:localhost:tede/832 |
| Date | 24 February 2006 |
| Creators | Silva, Sandra Borges da |
| Contributors | Bittencourt, V?nia Rita Elias Pinheiro, Carneiro, Maria Elisa, Faccini, Jo?o Luiz Horacio |
| Publisher | Universidade Federal Rural do Rio de Janeiro, Curso de P?s-Gradua??o em Ci?ncias Veterin?rias, UFRRJ, Brasil, Parasitologia Veterin?ria |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da UFRRJ, instname:Universidade Federal Rural do Rio de Janeiro, instacron:UFRRJ |
| Rights | info:eu-repo/semantics/openAccess |
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