RESUMO
Despite the importance of fat body in metabolism of arthropods, studies in ticks are scarce. This study evaluated the lipid composition and activation of extracellular signal-regulated protein kinase (ERK) and AMP-activated protein kinase (AMPK) enzymes in Rhipicephalus microplus fat body after infection with different isolates of the fungus Metarhizium anisopliae sensu lato (Metschnikoff, 1879) Sorokin, 1883. The isolates CG 32, GC 112, GC 148, GC 347, and GC 629 were inoculated as viable or non-viable conidia in the ticks. The engorged females were dissected, and their fat bodies were collected 24 and 48 h after infection. The lipid composition was assessed by thin layer chromatography, and enzyme activation was detected by Western blotting with antibodies against p-AMPK and p-ERK. The study showed increased levels of triacylglycerol 24 and 48 h and fatty acid after 48 h after inoculation with different isolates of viable fungi in the tick's hemocoel. Detection of the active form of ERK was demonstrated only after inoculation with non-viable conidia of all isolates tested. The active form of AMPK, only isolate CG 112 was able to activate with viable or non-viable conidia, whereas isolates CG 32 and CG 629 were able to activate with non-viable conidia. This study provides the first report about changes in important metabolic pathways in ticks infected with entomopathogenic fungi and suggests that the lipid content is modulated by non-usual pathways. However, further studies may be necessary for a better elucidation of this interaction.
Assuntos
Metabolismo dos Lipídeos , Sistema de Sinalização das MAP Quinases , Metarhizium/fisiologia , Rhipicephalus/microbiologia , Animais , Cromatografia em Camada Fina , Corpo Adiposo/metabolismo , Feminino , Rhipicephalus/metabolismo , Esporos FúngicosRESUMO
The effect of Beauveria bassiana, Metarhizium anisopliae, Penicillium corylophilum or Fusarium oxysporum on the dynamic of hemocytes presented in the haemolymph of engorged females of Boophilus microplus was studied. The inoculation was carried out with conidia suspension of different fungi in the concentration of 10(8) conidia/ml. A negative control group was inoculated with 0.1% Tween 80 water solution and a testimony group was comprised of non inoculated ticks. The haemolymph samples were collected in 24, 48 and 72 hours post-challenge. In all the studied periods, prohemocytes, plasmatocytes, granulocytes, spherulocytes and oenocytoids were observed in the specimens inoculated with fungus and also in the controls groups (negative and testimony). Prohemocytes, plasmatocytes and spherulocytes were the most cells in the haemolymph. The absence of hemocytes 72h post-challenging was observed prior to the death of the specimens inoculated with B. bassiana suggesting a failure in the cellular response. Hyphae and conidia growth was observed in the samples treated with entomopathogenic fungi (B. bassiana or M. anisopliae). The groups treated with non entomopathogenic fungi (P. corylophilum or F. oxysporum) did not shown significant differences in relation to the negative control and testimony groups.
Assuntos
Beauveria , Fusarium , Hemócitos/imunologia , Metarhizium , Penicillium , Carrapatos/citologia , Carrapatos/microbiologia , Animais , FemininoRESUMO
The cattle tick Boophilus microplus is a serious concern to the Brazilian cattle industry. It causes decreased meat and milk production, low alimentary conversion, damage to leather and transmission of pathogens. The use of entomopathogenic fungi as biological control agents for ticks has shown promising results. This study tests the in vitro effects of two Metarhizium anisopliae isolates (E9 and 319) towards three stages of B. microplus: eggs, larvae and engorged females. The bioassays were composed of five treatment groups (concentrations: 10(5), 10(6), 10(7), 10(8) conidia/ml and the control) each one with ten repetitions. The stages were treated by immersion for three minutes. After the treatments, the females, eggs and larvae were incubated at 27 degrees C +/- 1 and RH >or= 80%. The main studied parameters were: percentage of larvae eclosion, percentage of larvae mortality and the indexes of nutritional and reproductive efficiency. In vitro tests of the fungal isolates showed effective control of the three stages of B. microplus, suggesting high potential for their use as a microbial control agent of the B. microplus tick.
Assuntos
Metarhizium/patogenicidade , Carrapatos/microbiologia , Animais , FemininoRESUMO
The present study was aimed at the evaluation of two isolates of Aspergillus flavus and two isolates of Penicilium corylophilum on third stage larvae of Musca domestica. The samples tested were isolated directly from M. domestica specimens. Third stage larvae were obtained from pupas of a laboratory colony. Four batches with 20 larvae were used for each of conidia dilution tested (105 to 108 conidia/ml). Larvae were dipped for one minute into conidia dilution, being then moved to dishes and kept under controlled environmental conditions. Two control groups were used: one received a treatment with spreading adhesive and the other one with no treatment at all. Larval surviving rates were: 57.50 percent and 86.25 percent for groups treated with 108 conidia/ml of A. flavus; and 63.75 percent and 72.50 percent for those who had received the same concentration of P. corylophilum conidia. Larval mortality rates were greater for groups that received higher conidia concentrations, and also increased directly proportional to exposition time. Adult hatching rates on treated groups, were affected by fungi treatment. It was concluded that A. flavus and P. corylophilum presented detrimental effects for third stage larvae of M. domestica
