Duplex system in the simple retina of a gastropod mollusc,Limax flavus L.

Suzuki, Hitoshi; Watanabe, Makoto; Tsukahara, Yasuo; Tasaki, Kyoji

doi:10.1007/bf00657527

Cited by 24 publications

(16 citation statements)

References 18 publications

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“…However, a larger percentage of animals was expected to avoid short-wavelength light if monochromatic light with an equivalent photon flux density was used instead. 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: 55%

“…2A), but they escaped only from short wavelength light if the irradiance was low (10 μW cm −2 ; Fig. 2B), consistent with the higher sensitivity of the slugs' eyes to short-wavelength light (Suzuki et al, 1979;Matsuo et al, 2017Matsuo et al, , 2019. We judged the avoidance behaviour based on whether more than half of the slug's body was within the dark compartment (criterion number 1).…”

Section: Wavelength Dependency Of Avoidance Behavioursupporting

confidence: 55%

“…The terrestrial gastropod slug Limax valentianus is nocturnal, and avoids light places in order not to lose water from its body. To do this, the slugs have a well-developed lens eye on the tip of their superior tentacles (STs), which can detect light with high sensitivity (Kataoka, 1975;Suzuki et al, 1979;Zieger et al, 2009;Land and Nilsson, 2012;Matsuo et al, 2017). Therefore, the slugs exhibit negative phototaxis behaviour, which is driven by comparing the intensities of incident light coming into the bilateral eyes (Crozier and Cole, 1929;Matsuo et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

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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: 55%

Section: Wavelength Dependency Of Avoidance Behavioursupporting

confidence: 55%

Section: Introductionmentioning

confidence: 99%

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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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“…corneus (490 nm and 495-500 nm, respectively: Zhukov & Gribakin 1990), the land snails Otalu lactea (490 nm: Gillary & Wolbarsht 1967), Helix lucorum (496 nm: Chernorizov et al 1994), and Limax sp. (480 nm: Suzuki et al 1979), according to D = 2.44p(A/A) and Mutthiessen's ratio was determined as fLIr, where f L is the focal length of the spherical lens and r is the radius of the lens.…”

Section: -D Reconstructionmentioning

confidence: 99%

Fixed focal‐length optics in pulmonate snails (Mollusca, Gastropoda): squaring phylogenetic background and ecophysiological needs (II)

Gál

Bobkova

Zhukov

et al. 2004

Invertebrate Biology

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Abstract. Our results suggest that freshwater pulmonates like Lymnaea stagnalis, Radix peregra, Physa fontinalis, and Planorbarius corneus have inherited from their terrestrial ancestors eyes with a spherical, immobile lens with fixed focal‐length optics. Unable to change the dioptric apparatus to form an image under water, modifications to the retina had to occur if sharp vision was required. Computer‐assisted calculations and 3‐D eye reconstructions demonstrate that the photoreceptors in the deeper, ventral pit are in a position to perceive focused images under water. Vision in air, however, would favour photoreceptive cells located in the shallower, dorsal pit. On the basis of histological, ethological, and optical comparisons, we conclude that the eyes in L. stagnalis and R. peregra, species that are known to escape and seek temporary refuge above the water surface, are well adapted to function in water as well as air, but that the eyes in P. fontinalis and Pl. corneus are less modified from those of their terrestrial ancestors. We also conclude that good resolving power may be of greater importance in the aquatic pulmonates than the terrestrial species, since the former have to locate thin, vertical stems of reeds and sedges to ascend in order to reach the surface to breathe.

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“…The functional difference between the rod-and cone systems has been most conveniently demonstrated by constructing a dark adaptation curve (Suzuki et al 1979). The increase of the human retinal sensitivity during dark adaptation process has been expressed by a two-limbed curve with a noticeable break, the Kohlrausch kink, occurring after about 7 min in the dark (see, for example, Cornsweet 1970; Grusser and Grusser-Cornehls 1978).…”

mentioning

confidence: 99%

Human rods are acting in the light and cones are inhibited in the dark.

Sugita

Suzuki

Tasaki

1989

Tohoku J. Exp. Med.

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Rods are Acting in the Light and Cones are Inhibited in the Dark. Tohoku J. Exp. Med., 1989, 157 (4), [365][366][367][368][369][370][371][372] The light-and color detection thresholds were measured at three different states of retinal adaptation, i.e., light-and dark adapted states and the intermediate state which was obtained just before the Kohlrausch kink in the course of dark adaptation. At 20° from fixation in the nasal visual field, the wavelength function was examined. The color threshold was higher in the dark adapted state than in the state just before the kink, and the amount of increase was more prominent when the wavelength of the stimulus light was closer to the peak wavelength of rod sensitivity. It was concluded that the rod activation interferes with the cone sensitivity, and that the interference effect becomes stronger as a function of the responsiveness of rods. On the other hand, the spectral sensitivity curve determined in the light adapted state could be divided into two parts. The curve for shorter wavelength than 500 nm was well fitted by the scotopic luminosity curve, suggesting that the light threshold for shorter wavelength is determined by the rod system even in the light adapted state.rods ; cones ; adaptation ; spectral sensitivity ; color vision Two different systems are in the human retina : the rod system is very sensitive in the dark and the cone system, spatial and temporal resolutions of which are much higher than those of the rod system, works in the light. The functional difference between the rod-and cone systems has been most conveniently demonstrated by constructing a dark adaptation curve (Suzuki et al. 1979). The increase of the human retinal sensitivity during dark adaptation process has been expressed by a two-limbed curve with a noticeable break, the Kohlrausch kink, occurring after about 7 min in the dark (see, for example, Cornsweet 1970;Grusser and Grusser-Cornehls 1978). The first part of the curve has been assumed to be due to a rapid increase of the cone system while the second part to the increasing sensitivity of the rod system. Accordingly, the kink has been postulated to be caused by the crossover of the dark adaptation curves of rods and cones,

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Duplex system in the simple retina of a gastropod mollusc,Limax flavus L.

Cited by 24 publications

References 18 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

Fixed focal‐length optics in pulmonate snails (Mollusca, Gastropoda): squaring phylogenetic background and ecophysiological needs (II)

Human rods are acting in the light and cones are inhibited in the dark.

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