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Circadian clock of Aedes aegypti: effects of blood-feeding, insemination and RNA interference.

Gentile C, Rivas GB, Lima JB, Bruno RV, Peixoto AA - Mem. Inst. Oswaldo Cruz (2013)

Bottom Line: We show that blood intake, but not insemination, is responsible for the down-regulation of clock genes.Using RNA interference, we observe a slight reduction in the evening activity peak in the fourth day after dstim injection.These data suggest that, as in Drosophila, clock gene expression, circadian behaviour and environmental light regimens are interconnected in Ae. aegypti.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Biologia Molecular, Laboratório de Biologia Molecular.

ABSTRACT
Mosquitoes are the culprits of some of the most important vector borne diseases. A species' potential as a vector is directly dependent on their pattern of behaviour, which is known to change according to the female's physiological status such as whether the female is virgin/mated and unfed/blood-fed. However, the molecular mechanism triggered by and/or responsible for such modulations in behaviour is poorly understood. Clock genes are known to be responsible for the control of circadian behaviour in several species. Here we investigate the impact mating and blood-feeding have upon the expression of these genes in the mosquito Aedes aegypti. We show that blood intake, but not insemination, is responsible for the down-regulation of clock genes. Using RNA interference, we observe a slight reduction in the evening activity peak in the fourth day after dstim injection. These data suggest that, as in Drosophila, clock gene expression, circadian behaviour and environmental light regimens are interconnected in Ae. aegypti.

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: expression of timeless relative to the constitutive generp49 in the head and body of Aedes aegypti females injected with either timeless (tim ) or lac Z double-stranded RNA(dsRNA). The highest value between these two is used as reference. A t test was used to compare dstim and dsLacZ in each condition and all presented significant differences (p < 0.05), marked by asterisks. Statistics indicates thatconcerning gene expression results, there are no differences between the twoindependent experiments (DD: constant darkness; LD: light/dark cycles). It alsoindicates only the fourth day after the injection with the dsRNA hassignificant change in gene expression on the group injected withdstim relative to the control group injected with dsRNAlacZ (ANOVA, F1.58 = 9.708; p < 0.003). Therefore, this figure depicts only thestatistically significant result of the fourth day after injections of bothexperiments. The greater reduction in tim expression observedin the head relative to the body specifically on the fourth day after injectionhad also been proven significant (ANOVA, F1.58 = 8.226; p < 0.006). Error bars show standard error.
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f02: : expression of timeless relative to the constitutive generp49 in the head and body of Aedes aegypti females injected with either timeless (tim ) or lac Z double-stranded RNA(dsRNA). The highest value between these two is used as reference. A t test was used to compare dstim and dsLacZ in each condition and all presented significant differences (p < 0.05), marked by asterisks. Statistics indicates thatconcerning gene expression results, there are no differences between the twoindependent experiments (DD: constant darkness; LD: light/dark cycles). It alsoindicates only the fourth day after the injection with the dsRNA hassignificant change in gene expression on the group injected withdstim relative to the control group injected with dsRNAlacZ (ANOVA, F1.58 = 9.708; p < 0.003). Therefore, this figure depicts only thestatistically significant result of the fourth day after injections of bothexperiments. The greater reduction in tim expression observedin the head relative to the body specifically on the fourth day after injectionhad also been proven significant (ANOVA, F1.58 = 8.226; p < 0.006). Error bars show standard error.

Mentions: RNAi knockdown of tim expression and its effects on activity behaviour- We conducted injections of in vitro synthesised tim dsRNA in adultAe. aegypti females and monitored the effect of this interventionon the pattern of the mosquitoes activity/rest behaviour under two different conditions,LD and DD. The efficacy of the RNAi in reducing tim expression wasevaluated in head and body of mosquitoes collected on the fourth day after the dsRNAinjection using qRT-PCR. A significant reduction in tim expression wasdetected in both heads and bodies in the two experiments ( Fig. 2 ).


Circadian clock of Aedes aegypti: effects of blood-feeding, insemination and RNA interference.

Gentile C, Rivas GB, Lima JB, Bruno RV, Peixoto AA - Mem. Inst. Oswaldo Cruz (2013)

: expression of timeless relative to the constitutive generp49 in the head and body of Aedes aegypti females injected with either timeless (tim ) or lac Z double-stranded RNA(dsRNA). The highest value between these two is used as reference. A t test was used to compare dstim and dsLacZ in each condition and all presented significant differences (p < 0.05), marked by asterisks. Statistics indicates thatconcerning gene expression results, there are no differences between the twoindependent experiments (DD: constant darkness; LD: light/dark cycles). It alsoindicates only the fourth day after the injection with the dsRNA hassignificant change in gene expression on the group injected withdstim relative to the control group injected with dsRNAlacZ (ANOVA, F1.58 = 9.708; p < 0.003). Therefore, this figure depicts only thestatistically significant result of the fourth day after injections of bothexperiments. The greater reduction in tim expression observedin the head relative to the body specifically on the fourth day after injectionhad also been proven significant (ANOVA, F1.58 = 8.226; p < 0.006). Error bars show standard error.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4109183&req=5

f02: : expression of timeless relative to the constitutive generp49 in the head and body of Aedes aegypti females injected with either timeless (tim ) or lac Z double-stranded RNA(dsRNA). The highest value between these two is used as reference. A t test was used to compare dstim and dsLacZ in each condition and all presented significant differences (p < 0.05), marked by asterisks. Statistics indicates thatconcerning gene expression results, there are no differences between the twoindependent experiments (DD: constant darkness; LD: light/dark cycles). It alsoindicates only the fourth day after the injection with the dsRNA hassignificant change in gene expression on the group injected withdstim relative to the control group injected with dsRNAlacZ (ANOVA, F1.58 = 9.708; p < 0.003). Therefore, this figure depicts only thestatistically significant result of the fourth day after injections of bothexperiments. The greater reduction in tim expression observedin the head relative to the body specifically on the fourth day after injectionhad also been proven significant (ANOVA, F1.58 = 8.226; p < 0.006). Error bars show standard error.
Mentions: RNAi knockdown of tim expression and its effects on activity behaviour- We conducted injections of in vitro synthesised tim dsRNA in adultAe. aegypti females and monitored the effect of this interventionon the pattern of the mosquitoes activity/rest behaviour under two different conditions,LD and DD. The efficacy of the RNAi in reducing tim expression wasevaluated in head and body of mosquitoes collected on the fourth day after the dsRNAinjection using qRT-PCR. A significant reduction in tim expression wasdetected in both heads and bodies in the two experiments ( Fig. 2 ).

Bottom Line: We show that blood intake, but not insemination, is responsible for the down-regulation of clock genes.Using RNA interference, we observe a slight reduction in the evening activity peak in the fourth day after dstim injection.These data suggest that, as in Drosophila, clock gene expression, circadian behaviour and environmental light regimens are interconnected in Ae. aegypti.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Biologia Molecular, Laboratório de Biologia Molecular.

ABSTRACT
Mosquitoes are the culprits of some of the most important vector borne diseases. A species' potential as a vector is directly dependent on their pattern of behaviour, which is known to change according to the female's physiological status such as whether the female is virgin/mated and unfed/blood-fed. However, the molecular mechanism triggered by and/or responsible for such modulations in behaviour is poorly understood. Clock genes are known to be responsible for the control of circadian behaviour in several species. Here we investigate the impact mating and blood-feeding have upon the expression of these genes in the mosquito Aedes aegypti. We show that blood intake, but not insemination, is responsible for the down-regulation of clock genes. Using RNA interference, we observe a slight reduction in the evening activity peak in the fourth day after dstim injection. These data suggest that, as in Drosophila, clock gene expression, circadian behaviour and environmental light regimens are interconnected in Ae. aegypti.

Show MeSH
Related in: MedlinePlus