Clockwork blue: on the evolution of non-image-forming retinal photoreceptors in marine and terrestrial vertebrates

Erren, Thomas C.; Erren, Michael; Lerchl, Alexander; Meyer-Rochow, Victor Benno

doi:10.1007/s00114-007-0315-2

Cited by 11 publications

(9 citation statements)

References 57 publications

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“…We and other groups also demonstrated that the eye of Limax is more responsive to short-wavelength blue light, especially when the eye is light adapted (Suzuki et al, 1979;Matsuo et al, 2017Matsuo et al, , 2019. The preferential use of short-wavelength light is thought to be a widely conserved phenomenon in the animal kingdom (Gehring and Rosbash, 2003;Erren et al, 2008), and the slugs also appear to have inherited this trait.…”

Section: ) Andsupporting

confidence: 54%

Light avoidance by non-ocular photosensing system in the terrestrial slugLimax valentianus

Nishiyama

Nagata

Matsuo

et al. 2019

Journal of Experimental Biology

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Although the eye is the best-studied photoreceptive organ in animals, the presence of non-ocular photosensing systems has been reported in numerous animal species. However, most of the roles that nonocular photosensory systems play remain elusive. We found that the terrestrial slug Limax valentianus avoids light and escapes into dark areas even if it is blinded by the removal of the bilateral superior tentacle. The escape behaviour was more evident for short-wavelength light. Illumination to the head with blue but not red light elicited avoidance behaviour in the blinded slugs. Illumination to the tail was ineffective. The light-avoidance behaviour of the blinded slugs was not affected by the removal of the penis, which lies on the brain in the head, suggesting that the penis is dispensable for sensing light in the blinded slug. mRNA of Opn5A, xenopsin, retinochrome and, to a lesser extent, rhodopsin was expressed in the brain according to RT-PCR. Lightevoked neural responses were recorded from the left cerebro-pleural connective of the isolated suboesophageal ganglia of the brain, revealing that the brain is sensitive to short wavelengths of light (400-480 nm). This result is largely consistent with the wavelength dependency of the light-avoidance behaviour of the blinded slugs that we observed in the present study. Our results strongly support that the terrestrial slug L. valentianus detects and avoids light by using its brain as a light-sensing organ in the absence of eyes.

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Section: ) Andsupporting

confidence: 54%

Light avoidance by non-ocular photosensing system in the terrestrial slugLimax valentianus

Nishiyama

Nagata

Matsuo

et al. 2019

Journal of Experimental Biology

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“…Many photoreceptors involved in non-image-forming tasks appear to peak close to 480 nm, with a spread ranging from 460 to 530 nm. Melanopsin seems to be a common feature of all vertebrates (Table 1) that mediates non-visual retinal photoreception, which is dominated by blue light both in aquatic and terrestrial vertebrates [51]. Photoreceptive pigments generally evolved to mediate specific photoreceptive tasks in different photic environments [26].…”

Section: Evolutionary Aspects Of Diverse Photoreceptive Organsmentioning

confidence: 99%

Light Pollution, Circadian Photoreception, and Melatonin in Vertebrates

et al. 2019

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Artificial light at night (ALAN) is increasing exponentially worldwide, accelerated by the transition to new efficient lighting technologies. However, ALAN and resulting light pollution can cause unintended physiological consequences. In vertebrates, production of melatonin—the “hormone of darkness” and a key player in circadian regulation—can be suppressed by ALAN. In this paper, we provide an overview of research on melatonin and ALAN in vertebrates. We discuss how ALAN disrupts natural photic environments, its effect on melatonin and circadian rhythms, and different photoreceptor systems across vertebrate taxa. We then present the results of a systematic review in which we identified studies on melatonin under typical light-polluted conditions in fishes, amphibians, reptiles, birds, and mammals, including humans. Melatonin is suppressed by extremely low light intensities in many vertebrates, ranging from 0.01–0.03 lx for fishes and rodents to 6 lx for sensitive humans. Even lower, wavelength-dependent intensities are implied by some studies and require rigorous testing in ecological contexts. In many studies, melatonin suppression occurs at the minimum light levels tested, and, in better-studied groups, melatonin suppression is reported to occur at lower light levels. We identify major research gaps and conclude that, for most groups, crucial information is lacking. No studies were identified for amphibians and reptiles and long-term impacts of low-level ALAN exposure are unknown. Given the high sensitivity of vertebrate melatonin production to ALAN and the paucity of available information, it is crucial to research impacts of ALAN further in order to inform effective mitigation strategies for human health and the wellbeing and fitness of vertebrates in natural ecosystems.

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“…More recently, nocturnal production levels of melatonin have been shown to be inversely correlated with irradiances of narrowband blue LED light (peak l ¼ 469 nm; half peak bandwidth ¼ 26 nm) and the suppression impact of this narrow spectrum was more severe than that of 4000k white florescent light at twice the energy of the former [56,61]. Interestingly, blue-shifted photosensitivity of the retinal non-visual photoreceptors is postulated to be a conserved adapted feature of all vertebrates, which initially was adapted to the local blue-rich spectral composition of oceanic environments and selected later to be a unique ocular feature of all terrestrial vertebrates [62]. ALAN pollution has become a major problem for both environment stability and human health.…”

Section: Melatonin Suppressionmentioning

confidence: 99%

Artificial light at night: melatonin as a mediator between the environment and epigenome

Haim

Zubidat

2015

Phil. Trans. R. Soc. B

107

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The adverse effects of excessive use of artificial light at night (ALAN) are becoming increasingly evident and associated with several health problems including cancer. Results of epidemiological studies revealed that the increase in breast cancer incidents co-distribute with ALAN worldwide. There is compiling evidence that suggests that melatonin suppression is linked to ALAN-induced cancer risks, but the specific genetic mechanism linking environmental exposure and the development of disease is not well known. Here we propose a possible genetic link between environmental exposure and tumorigenesis processes. We discuss evidence related to the relationship between epigenetic remodelling and oncogene expression. In breast cancer, enhanced global hypomethylation is expected in oncogenes, whereas in tumour suppressor genes local hypermethylation is recognized in the promoter CpG chains. A putative mechanism of action involving epigenetic modifications mediated by pineal melatonin is discussed in relation to cancer prevalence. Taking into account that ALAN-induced epigenetic modifications are reversible, early detection of cancer development is of great significance in the treatment of the disease. Therefore, new biomarkers for circadian disruption need to be developed to prevent ALAN damage.

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Clockwork blue: on the evolution of non-image-forming retinal photoreceptors in marine and terrestrial vertebrates

Cited by 11 publications

References 57 publications

Light avoidance by non-ocular photosensing system in the terrestrial slugLimax valentianus

Light avoidance by non-ocular photosensing system in the terrestrial slugLimax valentianus

Light Pollution, Circadian Photoreception, and Melatonin in Vertebrates

Artificial light at night: melatonin as a mediator between the environment and epigenome

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