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The Light Wavelength Affects the Ontogeny of Clock Gene Expression and Activity Rhythms in Zebrafish Larvae.

Di Rosa V, Frigato E, López-Olmeda JF, Sánchez-Vázquez FJ, Bertolucci C - PLoS ONE (2015)

Bottom Line: The aim of this research was to determine the effect of light of different wavelengths (white, blue and red) on the onset of locomotor activity and clock gene (per1b, per2, clock1, bmal1 and dbp) expression rhythms.Curiously, bmal1 showed consistent rhythmic expression from embryonic stage (0 dpf).Summarizing, the data revealed that daily rhythms appeared earlier in the larvae reared under LDB than in those reared under LDW and LDR.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Faculty of Biology, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, Murcia Spain.

ABSTRACT
Light plays a key role in synchronizing rhythms and setting the phase of early development. However, to date, little is known about the impact of light wavelengths during the ontogeny of the molecular clock and the behavioural rhythmicity. The aim of this research was to determine the effect of light of different wavelengths (white, blue and red) on the onset of locomotor activity and clock gene (per1b, per2, clock1, bmal1 and dbp) expression rhythms. For this purpose, 4 groups of zebrafish embryo/larvae were raised from 0 to 7 days post-fertilization (dpf) under the following lighting conditions: three groups maintained under light:dark (LD) cycles with white (full visible spectrum, LDW), blue (LDB), or red light (LDR), and one group raised under constant darkness (DD). The results showed that lighting conditions influenced activity rhythms. Larvae were arrhythmic under DD, while under LD cycles they developed wavelength-dependent daily activity rhythms which appeared earlier under LDB (4 dpf) than under LDW or LDR (5 dpf). The results also revealed that development and lighting conditions influenced clock gene expression. While clock1 rhythmic expression appeared in all lighting conditions at 7 dpf, per1b, per2 and dbp showed daily variations already at 3 dpf. Curiously, bmal1 showed consistent rhythmic expression from embryonic stage (0 dpf). Summarizing, the data revealed that daily rhythms appeared earlier in the larvae reared under LDB than in those reared under LDW and LDR. These results emphasize the importance of lighting conditions and wavelengths during early development for the ontogeny of daily rhythms of gene expression and how these rhythms are reflected on the behavioural rhythmicity of zebrafish larvae.

No MeSH data available.


Related in: MedlinePlus

Daily expression levels of clock1, bmal1, per1b, per2 and dbp at 0, 3, 7 dpf in zebrafish larvae.Larvae reared under different light conditions (LDW, LDB, LDR, DD) were sampled every 6 hours at 0 (A, D, G, L, O), 3 (B, E, H, M, P) and 7 (C, F, I, N, Q) dpf. Data are expressed in % (100% is the maximum level detected for each gene in all dpf) and each value represents mean ± SEM (n = 4). The bars above each group indicate the daily LD cycle. White bars represent the light phase and black bars represent phases of darkness. The DD group was kept under constant darkness. Asterisks indicate significant rhythms identified by Cosinor analysis (p<0.05).
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pone.0132235.g004: Daily expression levels of clock1, bmal1, per1b, per2 and dbp at 0, 3, 7 dpf in zebrafish larvae.Larvae reared under different light conditions (LDW, LDB, LDR, DD) were sampled every 6 hours at 0 (A, D, G, L, O), 3 (B, E, H, M, P) and 7 (C, F, I, N, Q) dpf. Data are expressed in % (100% is the maximum level detected for each gene in all dpf) and each value represents mean ± SEM (n = 4). The bars above each group indicate the daily LD cycle. White bars represent the light phase and black bars represent phases of darkness. The DD group was kept under constant darkness. Asterisks indicate significant rhythms identified by Cosinor analysis (p<0.05).

Mentions: Embryos during the first 24 hours of life (0 dpf) showed variation of expression levels in all genes investigated (one-way ANOVA, p<0.05; Fig 4A–4E) and these variations were not affected by lighting conditions (two-way ANOVA, p>0.3; Fig 4A–4E). For the positive loop of the molecular clock, Cosinor analysis showed a significant rhythmicity (p<0.05) for bmal1 under LDW, LDR and DD, whereas clock1 expression levels were in all lighting conditions arrhythmic (p >0.05, Fig 4A and 4B). For the negative elements, per1b and per2 rhythmicity appeared only in some lighting conditions (Cosinor, p<0.05; per1b: LDW and LDR; per2: LDB; Fig 4C and 4D). The clock-controlled gene dbp was rhythmic in LDB, but not under the other lighting conditions (Fig 4E). At 0 dpf all rhythmic genes displayed their acrophases during the light phase, with the exception of per1b under LDW (ZT 13:13 h) (Table 1).


The Light Wavelength Affects the Ontogeny of Clock Gene Expression and Activity Rhythms in Zebrafish Larvae.

Di Rosa V, Frigato E, López-Olmeda JF, Sánchez-Vázquez FJ, Bertolucci C - PLoS ONE (2015)

Daily expression levels of clock1, bmal1, per1b, per2 and dbp at 0, 3, 7 dpf in zebrafish larvae.Larvae reared under different light conditions (LDW, LDB, LDR, DD) were sampled every 6 hours at 0 (A, D, G, L, O), 3 (B, E, H, M, P) and 7 (C, F, I, N, Q) dpf. Data are expressed in % (100% is the maximum level detected for each gene in all dpf) and each value represents mean ± SEM (n = 4). The bars above each group indicate the daily LD cycle. White bars represent the light phase and black bars represent phases of darkness. The DD group was kept under constant darkness. Asterisks indicate significant rhythms identified by Cosinor analysis (p<0.05).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492954&req=5

pone.0132235.g004: Daily expression levels of clock1, bmal1, per1b, per2 and dbp at 0, 3, 7 dpf in zebrafish larvae.Larvae reared under different light conditions (LDW, LDB, LDR, DD) were sampled every 6 hours at 0 (A, D, G, L, O), 3 (B, E, H, M, P) and 7 (C, F, I, N, Q) dpf. Data are expressed in % (100% is the maximum level detected for each gene in all dpf) and each value represents mean ± SEM (n = 4). The bars above each group indicate the daily LD cycle. White bars represent the light phase and black bars represent phases of darkness. The DD group was kept under constant darkness. Asterisks indicate significant rhythms identified by Cosinor analysis (p<0.05).
Mentions: Embryos during the first 24 hours of life (0 dpf) showed variation of expression levels in all genes investigated (one-way ANOVA, p<0.05; Fig 4A–4E) and these variations were not affected by lighting conditions (two-way ANOVA, p>0.3; Fig 4A–4E). For the positive loop of the molecular clock, Cosinor analysis showed a significant rhythmicity (p<0.05) for bmal1 under LDW, LDR and DD, whereas clock1 expression levels were in all lighting conditions arrhythmic (p >0.05, Fig 4A and 4B). For the negative elements, per1b and per2 rhythmicity appeared only in some lighting conditions (Cosinor, p<0.05; per1b: LDW and LDR; per2: LDB; Fig 4C and 4D). The clock-controlled gene dbp was rhythmic in LDB, but not under the other lighting conditions (Fig 4E). At 0 dpf all rhythmic genes displayed their acrophases during the light phase, with the exception of per1b under LDW (ZT 13:13 h) (Table 1).

Bottom Line: The aim of this research was to determine the effect of light of different wavelengths (white, blue and red) on the onset of locomotor activity and clock gene (per1b, per2, clock1, bmal1 and dbp) expression rhythms.Curiously, bmal1 showed consistent rhythmic expression from embryonic stage (0 dpf).Summarizing, the data revealed that daily rhythms appeared earlier in the larvae reared under LDB than in those reared under LDW and LDR.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Faculty of Biology, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, Murcia Spain.

ABSTRACT
Light plays a key role in synchronizing rhythms and setting the phase of early development. However, to date, little is known about the impact of light wavelengths during the ontogeny of the molecular clock and the behavioural rhythmicity. The aim of this research was to determine the effect of light of different wavelengths (white, blue and red) on the onset of locomotor activity and clock gene (per1b, per2, clock1, bmal1 and dbp) expression rhythms. For this purpose, 4 groups of zebrafish embryo/larvae were raised from 0 to 7 days post-fertilization (dpf) under the following lighting conditions: three groups maintained under light:dark (LD) cycles with white (full visible spectrum, LDW), blue (LDB), or red light (LDR), and one group raised under constant darkness (DD). The results showed that lighting conditions influenced activity rhythms. Larvae were arrhythmic under DD, while under LD cycles they developed wavelength-dependent daily activity rhythms which appeared earlier under LDB (4 dpf) than under LDW or LDR (5 dpf). The results also revealed that development and lighting conditions influenced clock gene expression. While clock1 rhythmic expression appeared in all lighting conditions at 7 dpf, per1b, per2 and dbp showed daily variations already at 3 dpf. Curiously, bmal1 showed consistent rhythmic expression from embryonic stage (0 dpf). Summarizing, the data revealed that daily rhythms appeared earlier in the larvae reared under LDB than in those reared under LDW and LDR. These results emphasize the importance of lighting conditions and wavelengths during early development for the ontogeny of daily rhythms of gene expression and how these rhythms are reflected on the behavioural rhythmicity of zebrafish larvae.

No MeSH data available.


Related in: MedlinePlus