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H Kobayashi - One of the best experts on this subject based on the ideXlab platform.
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The relationship between the length of the cupulae of free Neuromasts and feeding ability in larvae of the willow shiner Gnathopogon elongatus caerulescens (Teleostei, Cyprinidae
The Journal of experimental biology, 1994Co-Authors: Yukinori Mukai, Hiromasa Yoshikawa, H KobayashiAbstract:Free mechanosensory Neuromasts of larval fishes have been described as playing a complementary role to vision in feeding behaviour (Disler, 1971; Iwai, 1972a,b). In certain species or under limited conditions, free Neuromasts play a major role in detecting prey. The larvae of mottled sculpin Cottus bairdi can feed on Artemia in the dark by using free Neuromasts (Jones and Janssen, 1992). Artificially blinded surface-feeding Aplocheilus lineatus can detect insects on the water surface by means of free Neuromasts (Muller and Schwarts, 1982; Tittel et al. 1984; Bleckmann, 1988; Bleckmann et al. 1989). Furthermore, vibrations produced by swimming crustaceans are known to be a potent natural stimulus for the lateral line system in the Antarctic fish Pagothenia borchgrevinki (Montgomery and Macdonald, 1987; Montgomery, 1989). We found that larvae of a plankton feeder, the willow shiner Gnathopogon elongatus caerulescens (Sauvage) (Cypriniformes, Cyprinidae), fed on nauplii of Artemia in complete darkness. Ototoxic compounds, such as streptomycin, have been shown to disturb the function of the lateral line organ or free Neuromasts (Kaus, 1987; Blaxter and Fuiman, 1989; Janssen, 1990; Jones and Janssen, 1992). Willow shiner larvae treated with streptomycin sulphate no longer feed on Artemia in the dark (Y. Mukai, in preparation). The willow shiner inhabits calm lakes and feeds on zooplanktonic prey (Nakamura, 1949). The larvae show a high sensitivity to minute water displacements. From these observations and from our findings, it appears that larval willow shiner must feed on zooplankton by using free Neuromasts in the dark. In larval willow shiner, the vane-like cupulae of the free Neuromasts protrude from the body surface and the long cupulae are 100-250 microm in length (Mukai and Kobayashi, 1991). The prey is detected by the free Neuromasts as a result of a slight bending of the cupula in response to local water movements. The shape of the cupula, especially its length, must therefore be related to the sensitivity of the free neuromast, as inferred from the results of Coombs and Janssen (1989) and van Netten and Kroese (1989).
Yukinori Mukai - One of the best experts on this subject based on the ideXlab platform.
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Role of free Neuromasts in larval feeding of willow shiner Gnathopogon elongatus caerulescens Teleostei, Cyprinidae
Fisheries Science, 2006Co-Authors: Yukinori MukaiAbstract:It has been reported that the larvae of willow shiner Gnathopogon elongatus caerulescens have many free Neuromasts on their body surface. This study examined the ability of the willow shiner larvae to feed on zooplankton by mechanoreception by the free Neuromasts. Feeding experiments using untreated larvae and larvae treated with streptomycin, which impairs free neuromast function, were conducted under light and completely dark conditions. The larvae were put into Petri dishes, then nauplii of Artemia salina were introduced. The average number of Artemia eaten by the larvae was expressed as the average ingestion rate of Artemia /10 min. The ingestion rate of Artemia for untreated larvae was 12.3 under light conditions and 10.6 Artemia /10 min. even in complete darkness. The ingestion rate in the larvae treated with streptomycin was 11 under light conditions and only 0.8 Artemia /10 min under dark conditions. The low rate in the treated larvae under dark conditions must be due to impairment by the streptomycin. Therefore, the high ingestion rate for the untreated larvae under dark conditions would be surely dependent on mechanoreception. The results indicate that larval willow shiner is able to feed on zooplankton under limited light conditions.
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Development of free Neuromasts in larvae of mouse grouper, Cromileptes altivelis
2006Co-Authors: Audrey Daning Tuzan, Yukinori Mukai, Shigeharu SenooAbstract:This study was conducted to clarify the development of free Neuromasts in larvae of mouse grouper Cromileptes altivelis. A pair of free Neuromasts was observed behind the eyes in newly hatched larvae. The number of free Neuromasts increased with larval growth. Three-day-old larvae started ingesting rotifers and had 6 pairs of free Neuromasts on the head and 4 free Neuromasts on the unilateral side of the trunk. Free Neuromasts were distributed around the eyes on the head, and on the middle of the trunk. The apical surface of the free Neuromasts changed in outline from a circular shape to a lozenge shape, suggesting that the shape of the cupula changes from a stick-like shape to a vane-like shape. The number of sensory cells of the free Neuromasts increased with larval growth. The orientation of physiological maximum sensitivity of free Neuromasts, decided from the polarity of the sensory cells, coincided with the minor axis of the lozenge-shaped outline of the apical surface. The polarity of the trunk Neuromasts was usually oriented along the antero-posterior axis of the fish body, but a few had dorso-ventral orientation. On the head, the free Neuromasts were oriented on lines tangential to concentric circles around the eye, hence the free Neuromasts on the head could detect stimuli from various angles. It was considered that free Neuromasts of mouse grouper play an important role in avoiding predators, especially until the eyes begin to function.
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The relationship between the length of the cupulae of free Neuromasts and feeding ability in larvae of the willow shiner Gnathopogon elongatus caerulescens (Teleostei, Cyprinidae
The Journal of experimental biology, 1994Co-Authors: Yukinori Mukai, Hiromasa Yoshikawa, H KobayashiAbstract:Free mechanosensory Neuromasts of larval fishes have been described as playing a complementary role to vision in feeding behaviour (Disler, 1971; Iwai, 1972a,b). In certain species or under limited conditions, free Neuromasts play a major role in detecting prey. The larvae of mottled sculpin Cottus bairdi can feed on Artemia in the dark by using free Neuromasts (Jones and Janssen, 1992). Artificially blinded surface-feeding Aplocheilus lineatus can detect insects on the water surface by means of free Neuromasts (Muller and Schwarts, 1982; Tittel et al. 1984; Bleckmann, 1988; Bleckmann et al. 1989). Furthermore, vibrations produced by swimming crustaceans are known to be a potent natural stimulus for the lateral line system in the Antarctic fish Pagothenia borchgrevinki (Montgomery and Macdonald, 1987; Montgomery, 1989). We found that larvae of a plankton feeder, the willow shiner Gnathopogon elongatus caerulescens (Sauvage) (Cypriniformes, Cyprinidae), fed on nauplii of Artemia in complete darkness. Ototoxic compounds, such as streptomycin, have been shown to disturb the function of the lateral line organ or free Neuromasts (Kaus, 1987; Blaxter and Fuiman, 1989; Janssen, 1990; Jones and Janssen, 1992). Willow shiner larvae treated with streptomycin sulphate no longer feed on Artemia in the dark (Y. Mukai, in preparation). The willow shiner inhabits calm lakes and feeds on zooplanktonic prey (Nakamura, 1949). The larvae show a high sensitivity to minute water displacements. From these observations and from our findings, it appears that larval willow shiner must feed on zooplankton by using free Neuromasts in the dark. In larval willow shiner, the vane-like cupulae of the free Neuromasts protrude from the body surface and the long cupulae are 100-250 microm in length (Mukai and Kobayashi, 1991). The prey is detected by the free Neuromasts as a result of a slight bending of the cupula in response to local water movements. The shape of the cupula, especially its length, must therefore be related to the sensitivity of the free neuromast, as inferred from the results of Coombs and Janssen (1989) and van Netten and Kroese (1989).
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Development of free and canal Neuromasts and their directions of maximum sensitivity in the larvae of ayu,Plecoglossus altivelis
Japanese Journal of Ichthyology, 1992Co-Authors: Yukinori Mukai, Hiroshi Kobayashi, Hiromasa YoshikawaAbstract:Morphological changes in free Neuromasts are reported from larvae of the Ayu, Plecoglossus ahivelis. In newly-hatched larvae, free Neuromasts were already recognizable in both the head and trunk. During larval growth, the number of free Neuromasts increased, and the number of its sensory cells 2 days after hatching was constant. In the trunk, two types of free Neuromasts, one with maximum sensitivity in the antero-posterior direction and the other with maximum sensitivity in the dorso-ventral direction, were observed. The former type predominated. In the head, free Neuromasts were located around the eye and nose, their directions of maximum sensitivity forming lines tangential to concentric circles about the eye and nose. Distinct changes in free Neuromasts occurred during the formation of the canal organ. The canal organ was first observed in the head region 64 days after hatching and in the trunk region 100 days after hatching. Concomitant with the formation of the canal organ, the profile of the cupulae of the free Neuromasts changed from a flat bar to semispherical. Sensory cells in the canal Neuromasts did not differ morphologically from those in the free Neuromasts. It is considered that there is a close relationship between the sensitivity of the neuromast and the shape of the cupula, i.e., that the free Neuromasts are adapted to slow water flow, as in lakes and the sea, while the Neuromasts in the canal organ are adapted to rapid water flow.
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Morphological studies on the cupulae of free Neuromasts along with the growth of larvae in cyprinid fish
NIPPON SUISAN GAKKAISHI, 1991Co-Authors: Yukinori Mukai, Hiroshi KobayashiAbstract:The free Neuromasts were morphologically investigated in the larvae of two cyprinid fish, Zacco platypus and Gnathopogon elongatus caerulescens. In Z. platypus that mainly inhabits rivers, cupulae increased in length and became flat in shape (the so-called nail type) along with growth in the larval stage. Afterwards, the cupulae became shorter during the juvenile stage. The short and nail type cupulae of Z. platypus seem to be adaptive to rheotactic swimming. On the other hand, in G. elongatus caerulescens that lives in lakes, the cupulae were long and did not change in length until the 72nd day after hatching in the juvenile stage, but it changed in shape from a stick to a flat type like marine algae (laminaria). The surface area of these cupulae is larger than that of Z. platypus, and therefore the cupulae of G. elongatus caerulescens will be more receptive to mechanical stimulus by water flow. The photographs (SEM) of neuromast showed that the direction of the best physiological sensitivity of sensory hair cells coincided with the minor axis of the outline of the neuromast area, namely the bending direction of cupulae. From these results, it was considered that the neuro-masts of G. elongates caerulescens have a high sensitivity not only regarding their swimming behavior but also for perceiving weak water movements caused by prey and predators.
Karine Faucher - One of the best experts on this subject based on the ideXlab platform.
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impact of acute cadmium exposure on the trunk lateral line Neuromasts and consequences on the c start response behaviour of the sea bass dicentrarchus labrax l teleostei moronidae
Aquatic Toxicology, 2006Co-Authors: Karine Faucher, Denis Fichet, Pierre Miramand, Jean Paul LagardereAbstract:Abstract Behavioural responses of sea bass Dicentrarchus labrax were investigated after exposure to cadmium ions in laboratory-controlled conditions. The aim of this study was to discover whether environmental exposure to cadmium ions inactivates fish lateral line system Neuromasts, and to determine the behavioural consequences of such a sensory blockage. For this, fish escape behaviour in response to an artificial water jet was recorded using a 25-frames s −1 analog video camera before and after cadmium exposure. Experimental set up was tested with fish whose lateral line system was artificially inactivated by antibiotics (gentamicin and streptomycin). Histological analyses with scanning electron microscopy showed antibiotic treatment destroyed lateral line system Neuromasts. In addition, these fish did not respond to stimulations provoked by the water jet after antibiotic treatment. Fish escape behaviour was then recorded before and after cadmium exposure at two different concentrations. When fish were exposed to the first concentration of cadmium tested (0.5 μg l −1 , which represents the maximal cadmium concentration encountered in contaminated estuaries), no alteration in neuromast tissue was observed. In addition, before cadmium exposure, fish responded positively in 98.41 ± 4.95% of lateral line system stimulations (escape behaviour in response to the water jet). After cadmium exposure, no behavioural modification could be detected: the fish responded positively in 95.16 ± 9.79% of stimulations ( χ 2 = 2.464, p = 0.116). In contrast, the high cadmium concentration used (5 μg l −1 , which represents 10 times the concentration occurring in highly polluted estuarine areas) involved severe neuromast tissue damage. Just after such cadmium exposure, fish showed only 41.67 ± 35.36% of positive responses to their lateral line system stimulations, while they responded positively in 95.93 ± 9.10% of stimulations under control conditions ( χ 2 = 24.562, p χ 2 = 2.876, p = 0.090). This study shows that although 5 μg l −1 cadmium is able to damage lateral line system Neuromasts and causes fish behavioural alterations, fish exposed to 0.5 μg l −1 cadmium displayed neither tissue neuromast nor behavioural modification.
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quantitative aspects of the spatial distribution and morphological characteristics of the sea bass dicentrarchus labrax l teleostei serranidae trunk lateral line Neuromasts
Brain Behavior and Evolution, 2005Co-Authors: Karine Faucher, Jean Paul Lagardere, Anne AubertAbstract:The results presented herein report quantitative data relative to the distribution and morphological characteristics of both types of Neuromasts encountered on the trunk lateral line of the sea bass (Dicentrarchus labrax, L.). These data were obtained from scanning electron micrographs. They indicate that, as expected, each modified scale of the sea bass possessed a single canal neuromast with long axis oriented parallel to the fish's long axis. In contrast to several fish species, two thirds of superficial Neuromasts observed herein were oriented perpendicular to the fish's long axis. However, whatever the main orientation of superficial Neuromasts, two thirds of their hair bundles were oriented parallel to the long axis of the animal with approximately half of them in the direction of the head. Similar ratios were observed for canal Neuromasts whatever the area of the maculae: central or peripheral. For both types of Neuromasts it was not possible to clearly distinguish a paired organization of hair bundles with opposing polarities. Superficial Neuromasts on each trunk canal scale were located on either the dorsal or ventral side of the canal and appeared to be distributed along the trunk lateral line with a higher probability to be encountered closer to the operculum. The frequency of presence and the average number of superficial Neuromasts per scale increased with fish size. We observed a size gradient for canal Neuromasts between the operculum and caudal peduncle. This gradation was correlated with a reduction of the width of the central area of the canal segment. Canal Neuromasts were always localized in the larger portions of the canal segments. Taken together, these results point out some specific features associated with the sea bass trunk lateral line. With the previous report, they establish the first full description of the trunk lateral line of sea bass and will be useful for upcoming experiments regarding the function of the two types of Neuromasts.
Matthew J Mchenry - One of the best experts on this subject based on the ideXlab platform.
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gentamicin is ototoxic to all hair cells in the fish lateral line system
Hearing Research, 2010Co-Authors: William J Van Trump, Sheryl Coombs, Kyle Duncan, Matthew J MchenryAbstract:Hair cells of the lateral line system in fish may differ in their susceptibility to damage by aminoglycoside antibiotics. Gentamicin has been reported to damage hair cells within canal Neuromasts, but not those within superficial Neuromasts. This finding, based on SEM imaging, indicates a distinction in the physiology of hair cells between the two classes of neuromast. Studies concerned with the individual roles of canal and superficial Neuromasts in behavior have taken advantage of this effect in an attempt to selectively disable canal Neuromasts without affecting superficial neuromast function. Here we present an experimental test of the hypothesis that canal Neuromasts are more vulnerable to gentamicin than superficial Neuromasts. We measured the effect of gentamicin exposure on hair cells using vital stains (DASPEI and FM1-43) in the Neuromasts of Mexican blind cave fish (Astyanaxfasciatus) and zebrafish (Daniorerio). Contrary to the findings of prior studies that used SEM, gentamicin significantly reduced dye uptake by hair cells of both canal and superficial Neuromasts in both species. Therefore, lateral line hair cells of both neuromast types are vulnerable to gentamicin ototoxicity. These findings argue for a re-evaluation of the results of studies that have used gentamicin to differentiate the roles of the two classes of neuromast in fish behavior.
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The flexural stiffness of superficial Neuromasts in the zebrafish (Danio rerio) lateral line.
Journal of Experimental Biology, 2007Co-Authors: Matthew J Mchenry, Sietse M. Van NettenAbstract:SUMMARY Superficial Neuromasts are structures that detect water flow on the surface of the body of fish and amphibians. As a component of the lateral line system, these receptors are distributed along the body, where they sense flow patterns that mediate a wide variety of behaviors. Their ability to detect flow is governed by their structural properties, yet the micromechanics of superficial Neuromasts are not well understood. The aim of this study was to examine these mechanics in zebrafish ( Danio rerio ) larvae by measuring the flexural stiffness of individual Neuromasts. Each neuromast possesses a gelatinous cupula that is anchored to hair cells by kinocilia. Using quasi-static bending tests of the proximal region of the cupula, we found that flexural stiffness is proportional to the number of hair cells, and consequently the number of kinocilia, within a neuromast. From this relationship, the flexural stiffness of an individual kinocilium was found to be 2.4×10 –20 N m 2 . Using this value, we estimate that the 11 kinocilia in an average cupula generate more than four-fifths of the total flexural stiffness in the proximal region. The relatively minor contribution of the cupular matrix may be attributed to its highly compliant material composition (Young9s modulus of ∼21 Pa). The distal tip of the cupula is entirely composed of this material and is consequently predicted to be at least an order of magnitude more flexible than the proximal region. These findings suggest that the transduction of flow by a superficial neuromast depends on structural dynamics that are dominated by the number and height of kinocilia.
Jean Paul Lagardere - One of the best experts on this subject based on the ideXlab platform.
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impact of acute cadmium exposure on the trunk lateral line Neuromasts and consequences on the c start response behaviour of the sea bass dicentrarchus labrax l teleostei moronidae
Aquatic Toxicology, 2006Co-Authors: Karine Faucher, Denis Fichet, Pierre Miramand, Jean Paul LagardereAbstract:Abstract Behavioural responses of sea bass Dicentrarchus labrax were investigated after exposure to cadmium ions in laboratory-controlled conditions. The aim of this study was to discover whether environmental exposure to cadmium ions inactivates fish lateral line system Neuromasts, and to determine the behavioural consequences of such a sensory blockage. For this, fish escape behaviour in response to an artificial water jet was recorded using a 25-frames s −1 analog video camera before and after cadmium exposure. Experimental set up was tested with fish whose lateral line system was artificially inactivated by antibiotics (gentamicin and streptomycin). Histological analyses with scanning electron microscopy showed antibiotic treatment destroyed lateral line system Neuromasts. In addition, these fish did not respond to stimulations provoked by the water jet after antibiotic treatment. Fish escape behaviour was then recorded before and after cadmium exposure at two different concentrations. When fish were exposed to the first concentration of cadmium tested (0.5 μg l −1 , which represents the maximal cadmium concentration encountered in contaminated estuaries), no alteration in neuromast tissue was observed. In addition, before cadmium exposure, fish responded positively in 98.41 ± 4.95% of lateral line system stimulations (escape behaviour in response to the water jet). After cadmium exposure, no behavioural modification could be detected: the fish responded positively in 95.16 ± 9.79% of stimulations ( χ 2 = 2.464, p = 0.116). In contrast, the high cadmium concentration used (5 μg l −1 , which represents 10 times the concentration occurring in highly polluted estuarine areas) involved severe neuromast tissue damage. Just after such cadmium exposure, fish showed only 41.67 ± 35.36% of positive responses to their lateral line system stimulations, while they responded positively in 95.93 ± 9.10% of stimulations under control conditions ( χ 2 = 24.562, p χ 2 = 2.876, p = 0.090). This study shows that although 5 μg l −1 cadmium is able to damage lateral line system Neuromasts and causes fish behavioural alterations, fish exposed to 0.5 μg l −1 cadmium displayed neither tissue neuromast nor behavioural modification.
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quantitative aspects of the spatial distribution and morphological characteristics of the sea bass dicentrarchus labrax l teleostei serranidae trunk lateral line Neuromasts
Brain Behavior and Evolution, 2005Co-Authors: Karine Faucher, Jean Paul Lagardere, Anne AubertAbstract:The results presented herein report quantitative data relative to the distribution and morphological characteristics of both types of Neuromasts encountered on the trunk lateral line of the sea bass (Dicentrarchus labrax, L.). These data were obtained from scanning electron micrographs. They indicate that, as expected, each modified scale of the sea bass possessed a single canal neuromast with long axis oriented parallel to the fish's long axis. In contrast to several fish species, two thirds of superficial Neuromasts observed herein were oriented perpendicular to the fish's long axis. However, whatever the main orientation of superficial Neuromasts, two thirds of their hair bundles were oriented parallel to the long axis of the animal with approximately half of them in the direction of the head. Similar ratios were observed for canal Neuromasts whatever the area of the maculae: central or peripheral. For both types of Neuromasts it was not possible to clearly distinguish a paired organization of hair bundles with opposing polarities. Superficial Neuromasts on each trunk canal scale were located on either the dorsal or ventral side of the canal and appeared to be distributed along the trunk lateral line with a higher probability to be encountered closer to the operculum. The frequency of presence and the average number of superficial Neuromasts per scale increased with fish size. We observed a size gradient for canal Neuromasts between the operculum and caudal peduncle. This gradation was correlated with a reduction of the width of the central area of the canal segment. Canal Neuromasts were always localized in the larger portions of the canal segments. Taken together, these results point out some specific features associated with the sea bass trunk lateral line. With the previous report, they establish the first full description of the trunk lateral line of sea bass and will be useful for upcoming experiments regarding the function of the two types of Neuromasts.
