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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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: activity/rest behaviour of two groups of Aedes aegyptifemale after the injection of double-stranded RNA (dsRNA) for seven days inlight-dark cycles (LD). One group was injected with timelessdsRNA (black line) and the other with lacZ dsRNA (grey area),used as control. White horizontal bars indicate lights-on and black horizontalbars indicate light-off. Graphics depict average activity according toWilliam’s mean (Haddow 1960). Readings on the 30 min after the transitions LDand dark-light were interpolated to smooth startle responses.
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f03: : activity/rest behaviour of two groups of Aedes aegyptifemale after the injection of double-stranded RNA (dsRNA) for seven days inlight-dark cycles (LD). One group was injected with timelessdsRNA (black line) and the other with lacZ dsRNA (grey area),used as control. White horizontal bars indicate lights-on and black horizontalbars indicate light-off. Graphics depict average activity according toWilliam’s mean (Haddow 1960). Readings on the 30 min after the transitions LDand dark-light were interpolated to smooth startle responses.

Mentions: The graph of locomotor activity depicted in Fig. 3shows similar patterns between dstim and dsLacZ , butwith different levels of activity during seven days in LD. Under LD cycles, we expect anactivity pattern with 24 h, which represents a proper entrainment of mosquitoes to theLD regime. However, we were unable to observe any significant differences in theproportion of rhythmic individuals between dsLacZ anddstim groups. Though, tim reduction decreases powerlevels ( Table II ). The power of the rhythm isusually defined as the amplitude from the top of the peak to the confidence level in theχ2 periodogram ( Liu et al. 1991 ) and it is usedas a parameter to measure the strength of the rhythm in a given environmental cycle.Thus we can assume that the power reduction in dstim mosquitoes is aconsequence of a deficient light entrainment in this group.


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)

: activity/rest behaviour of two groups of Aedes aegyptifemale after the injection of double-stranded RNA (dsRNA) for seven days inlight-dark cycles (LD). One group was injected with timelessdsRNA (black line) and the other with lacZ dsRNA (grey area),used as control. White horizontal bars indicate lights-on and black horizontalbars indicate light-off. Graphics depict average activity according toWilliam’s mean (Haddow 1960). Readings on the 30 min after the transitions LDand dark-light were interpolated to smooth startle responses.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f03: : activity/rest behaviour of two groups of Aedes aegyptifemale after the injection of double-stranded RNA (dsRNA) for seven days inlight-dark cycles (LD). One group was injected with timelessdsRNA (black line) and the other with lacZ dsRNA (grey area),used as control. White horizontal bars indicate lights-on and black horizontalbars indicate light-off. Graphics depict average activity according toWilliam’s mean (Haddow 1960). Readings on the 30 min after the transitions LDand dark-light were interpolated to smooth startle responses.
Mentions: The graph of locomotor activity depicted in Fig. 3shows similar patterns between dstim and dsLacZ , butwith different levels of activity during seven days in LD. Under LD cycles, we expect anactivity pattern with 24 h, which represents a proper entrainment of mosquitoes to theLD regime. However, we were unable to observe any significant differences in theproportion of rhythmic individuals between dsLacZ anddstim groups. Though, tim reduction decreases powerlevels ( Table II ). The power of the rhythm isusually defined as the amplitude from the top of the peak to the confidence level in theχ2 periodogram ( Liu et al. 1991 ) and it is usedas a parameter to measure the strength of the rhythm in a given environmental cycle.Thus we can assume that the power reduction in dstim mosquitoes is aconsequence of a deficient light entrainment in this group.

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