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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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: locomotor activity/rest behaviour of two groups of Ae.aegypti female after the injection of double-stranded RNA (dsRNA)for two days in light-dark cycles (LD) followed by five days in constantdarkness (DD). A: double-plotted actograms of representative mosquitoesinjected with dsLacZ and dstim . The data wassmoothed (Gaussian smoothing) using ActogramJ to reduce the noise and improvethe visualisation of actograms. The shaded dark grey areas indicate dark phaseand light grey areas indicate the subjective days in DD. The arrow shows areduction of activity in dstim mosquitoes on the fourth dayafter the injection; B: mean ± standard error of the means (lines) andindividual mosquito ( dslacZ , circles; dstim, squares) free running period length (hours). Statistical analysis byt test show a difference between dslacZand dstim (t = 2.158; p < 0.05). A dotted horizontal linemarks the 24 h value of y axis. CT: circadian time; ZT: Zeitgeber-time.
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f04: : locomotor activity/rest behaviour of two groups of Ae.aegypti female after the injection of double-stranded RNA (dsRNA)for two days in light-dark cycles (LD) followed by five days in constantdarkness (DD). A: double-plotted actograms of representative mosquitoesinjected with dsLacZ and dstim . The data wassmoothed (Gaussian smoothing) using ActogramJ to reduce the noise and improvethe visualisation of actograms. The shaded dark grey areas indicate dark phaseand light grey areas indicate the subjective days in DD. The arrow shows areduction of activity in dstim mosquitoes on the fourth dayafter the injection; B: mean ± standard error of the means (lines) andindividual mosquito ( dslacZ , circles; dstim, squares) free running period length (hours). Statistical analysis byt test show a difference between dslacZand dstim (t = 2.158; p < 0.05). A dotted horizontal linemarks the 24 h value of y axis. CT: circadian time; ZT: Zeitgeber-time.

Mentions: In another experiment, after two days in LD the mosquitoes were submitted to five daysin DD ( Fig. 4A ). In DD, the number of rhythmicindividuals diminishes equally between the two groups ( Table II ). Nevertheless, we observed a dramatic decrease in the activitylevels in the dstim group in the second DD day, which corresponds tothe fourth day after injection. After that, there is a gradual increase in the activitylevels, but with a delayed phase shift as compared to the dsLacZ group.Also, there is a significant difference in the free running period between the groups (Table II ), probably as a result of a greatvariety between individuals from the dstim group, which is not observedin the dsLacZ mosquitoes ( Fig.4B ).


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)

: locomotor activity/rest behaviour of two groups of Ae.aegypti female after the injection of double-stranded RNA (dsRNA)for two days in light-dark cycles (LD) followed by five days in constantdarkness (DD). A: double-plotted actograms of representative mosquitoesinjected with dsLacZ and dstim . The data wassmoothed (Gaussian smoothing) using ActogramJ to reduce the noise and improvethe visualisation of actograms. The shaded dark grey areas indicate dark phaseand light grey areas indicate the subjective days in DD. The arrow shows areduction of activity in dstim mosquitoes on the fourth dayafter the injection; B: mean ± standard error of the means (lines) andindividual mosquito ( dslacZ , circles; dstim, squares) free running period length (hours). Statistical analysis byt test show a difference between dslacZand dstim (t = 2.158; p < 0.05). A dotted horizontal linemarks the 24 h value of y axis. CT: circadian time; ZT: Zeitgeber-time.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f04: : locomotor activity/rest behaviour of two groups of Ae.aegypti female after the injection of double-stranded RNA (dsRNA)for two days in light-dark cycles (LD) followed by five days in constantdarkness (DD). A: double-plotted actograms of representative mosquitoesinjected with dsLacZ and dstim . The data wassmoothed (Gaussian smoothing) using ActogramJ to reduce the noise and improvethe visualisation of actograms. The shaded dark grey areas indicate dark phaseand light grey areas indicate the subjective days in DD. The arrow shows areduction of activity in dstim mosquitoes on the fourth dayafter the injection; B: mean ± standard error of the means (lines) andindividual mosquito ( dslacZ , circles; dstim, squares) free running period length (hours). Statistical analysis byt test show a difference between dslacZand dstim (t = 2.158; p < 0.05). A dotted horizontal linemarks the 24 h value of y axis. CT: circadian time; ZT: Zeitgeber-time.
Mentions: In another experiment, after two days in LD the mosquitoes were submitted to five daysin DD ( Fig. 4A ). In DD, the number of rhythmicindividuals diminishes equally between the two groups ( Table II ). Nevertheless, we observed a dramatic decrease in the activitylevels in the dstim group in the second DD day, which corresponds tothe fourth day after injection. After that, there is a gradual increase in the activitylevels, but with a delayed phase shift as compared to the dsLacZ group.Also, there is a significant difference in the free running period between the groups (Table II ), probably as a result of a greatvariety between individuals from the dstim group, which is not observedin the dsLacZ mosquitoes ( Fig.4B ).

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