The Experts below are selected from a list of 3537 Experts worldwide ranked by ideXlab platform
Atsuo Kawahara - One of the best experts on this subject based on the ideXlab platform.
-
Characterization of biklf/klf17-deficient zebrafish in posterior lateral line Neuromast and hatching gland development
Scientific Reports, 2019Co-Authors: Hiroaki Suzuki, Tomoe Ishizaka, Kanoko Yanagi, Ryota Sone, Yuto Sunaga, Rie Ohga, Atsuo KawaharaAbstract:Krupple-like factors (Klfs) are highly conserved zinc-finger transcription factors that regulate various developmental processes, such as haematopoiesis and cardiovascular development. In zebrafish, transient knockdown analysis of biklf/klf17 using antisense morpholino suggests the involvement of biklf/klf17 in primitive erythropoiesis and hatching gland development; however, the continuous physiological importance of klf17 remains uncharacterized under the genetic ablation of the klf17 gene among vertebrates. We established the klf17-disrupted zebrafish lines using the CRISPR/Cas9 technology and performed phenotypic analysis throughout early embryogenesis. We found that the klf17-deficient embryos exhibited abnormal lateral line Neuromast deposition, whereas the production of primitive erythrocytes and haemoglobin production were observed in the klf17-deficient embryos. The expression of lateral line Neuromast genes, klf17 and s100t, in the klf17-deficient embryos was detected in posterior lateral line Neuromasts abnormally positioned at short intervals. Furthermore, the klf17-deficient embryos failed to hatch and died without hatching around 15 days post-fertilization (dpf), whereas the dechorionated klf17-deficient embryos and wild-type embryos were alive at 15 dpf. The klf17-deficient embryos abolished hatching gland cells and Ctsl1b protein expression, and eliminated the expression of polster and hatching gland marker genes, he1.1, ctsl1b and cd63. Thus, the klf17 gene plays important roles in posterior lateral line Neuromast and hatching gland development.
-
characterization of biklf klf17 deficient zebrafish in posterior lateral line Neuromast and hatching gland development
Scientific Reports, 2019Co-Authors: Hiroaki Suzuki, Tomoe Ishizaka, Kanoko Yanagi, Ryota Sone, Yuto Sunaga, Rie Ohga, Atsuo KawaharaAbstract:Krupple-like factors (Klfs) are highly conserved zinc-finger transcription factors that regulate various developmental processes, such as haematopoiesis and cardiovascular development. In zebrafish, transient knockdown analysis of biklf/klf17 using antisense morpholino suggests the involvement of biklf/klf17 in primitive erythropoiesis and hatching gland development; however, the continuous physiological importance of klf17 remains uncharacterized under the genetic ablation of the klf17 gene among vertebrates. We established the klf17-disrupted zebrafish lines using the CRISPR/Cas9 technology and performed phenotypic analysis throughout early embryogenesis. We found that the klf17-deficient embryos exhibited abnormal lateral line Neuromast deposition, whereas the production of primitive erythrocytes and haemoglobin production were observed in the klf17-deficient embryos. The expression of lateral line Neuromast genes, klf17 and s100t, in the klf17-deficient embryos was detected in posterior lateral line Neuromasts abnormally positioned at short intervals. Furthermore, the klf17-deficient embryos failed to hatch and died without hatching around 15 days post-fertilization (dpf), whereas the dechorionated klf17-deficient embryos and wild-type embryos were alive at 15 dpf. The klf17-deficient embryos abolished hatching gland cells and Ctsl1b protein expression, and eliminated the expression of polster and hatching gland marker genes, he1.1, ctsl1b and cd63. Thus, the klf17 gene plays important roles in posterior lateral line Neuromast and hatching gland development.
Matthew J. Mchenry - One of the best experts on this subject based on the ideXlab platform.
-
the sensitivity of lateral line receptors and their role in the behavior of mexican blind cavefish astyanax mexicanus
The Journal of Experimental Biology, 2014Co-Authors: Masato Yoshizawa, William R Jeffery, Sietse M Van Netten, Matthew J. MchenryAbstract:The characid fish species Astyanax mexicanus offers a classic comparative model for the evolution of sensory systems. Populations of this species evolved in caves and became blind while others remained in streams (i.e. surface fish) and retained a functional visual system. The flow-sensitive lateral line receptors, called superficial Neuromasts, are more numerous in cavefish than in surface fish, but it is unclear whether individual Neuromasts differ in sensitivity between these populations. The aims of this study were to determine whether the Neuromasts in cavefish impart enhanced sensitivity relative to surface fish and to test whether this aids their ability to sense flow in the absence of visual input. Sensitivity was assessed by modeling the mechanics and hydrodynamics of a flow stimulus. This model required that we measure the dimensions of the transparent cupula of a Neuromast, which was visualized with fluorescent microspheres. We found that Neuromasts within the eye orbit and in the suborbital region were larger and consequently about twice as sensitive in small adult cavefish as in surface fish. Behavioral experiments found that these cavefish, but not surface fish, were attracted to a 35 Hz flow stimulus. These results support the hypothesis that the large superficial Neuromasts of small cavefish aid in flow sensing. We conclude that the morphology of the lateral line could have evolved in cavefish to permit foraging in a cave environment.
-
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.
-
The flexural stiffness of superficial Neuromasts in the zebrafish (Danio rerio) lateral line.
The Journal of experimental biology, 2007Co-Authors: Matthew J. Mchenry, Sietse M. Van NettenAbstract: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 x 10(-20) N m2. 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 (Young's modulus of approximately 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.
Alain Ghysen - One of the best experts on this subject based on the ideXlab platform.
-
Evolution of posterior lateral line development in fish and amphibians.
Evolution & Development, 2004Co-Authors: Fabien Pichon, Alain GhysenAbstract:The lateral line is a sensory system present in fish and amphibians. It is composed of discrete sense organs, the Neuromasts, arranged on the head and body in species-specific patterns. The Neuromasts are deposited by migrating primordia that originate from pre- and postotic placodes and follow defined pathways on the head and body. Here we examine the formation of the posterior lateral line (PLL), which extends rostrocaudally on the trunk and tail. In amphibians, the PLL Neuromasts are deposited as a single wave from the head to the tip of the tail. In the zebrafish, however, the first wave of Neuromast deposition forms but a rudimentary PLL, and several additional waves are needed to form the adult pattern. We show that the amphibian mode is also present in the sturgeon and therefore probably represents the primitive mode, whereas the zebrafish mode is highly conserved in several teleost species. A third mode is found in a subgroup of teleosts, the protacanthopterygians, and may represent a synapomorphy of this group. Altogether, the mode of formation of the embryonic PLL appears to have undergone remarkably few changes during the long history of anamniote evolution, even though large differences can be observed in the lateral line morphology of adult fishes.
-
Cell migration in the postembryonic development of the fish lateral line.
Development (Cambridge England), 2002Co-Authors: Dora Sapède, Nicolas Gompel, Christine Dambly-chaudière, Alain GhysenAbstract:We examine at the cellular level the postembryonic development of the posterior lateral line in the zebrafish. We show that the first wave of secondary Neuromasts is laid down by a migrating primordium, primII. This primordium originates from a cephalic region much like the primordium that formed the primary line during embryogenesis. PrimII contributes to both the lateral and the dorsal branches of the posterior lateral line. Once they are deposited by the primordium, the differentiating Neuromasts induce the specialisation of overlying epidermal cells into a pore-forming annulus, and the entire structure begins to migrate ventrally across the epithelium. Thus the final two-dimensional pattern depends on the combination of two orthogonal processes: anteroposterior waves of Neuromast formation and dorsoventral migration of individual Neuromasts. Finally, we examine how general these migratory processes can be by describing two fish species with very different adult patterns, Astyanax fasciatus (Mexican blind cavefish) and Oryzias latipes (medaka). We show that their primary patterns are nearly identical to that observed in zebrafish embryos, and that their postembryonic growth relies on the same combination of migratory processes that we documented in the case of the zebrafish.
Yukinori Mukai - One of the best experts on this subject based on the ideXlab platform.
-
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.
-
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).
-
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.
-
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.
Hiroaki Suzuki - One of the best experts on this subject based on the ideXlab platform.
-
Characterization of biklf/klf17-deficient zebrafish in posterior lateral line Neuromast and hatching gland development
Scientific Reports, 2019Co-Authors: Hiroaki Suzuki, Tomoe Ishizaka, Kanoko Yanagi, Ryota Sone, Yuto Sunaga, Rie Ohga, Atsuo KawaharaAbstract:Krupple-like factors (Klfs) are highly conserved zinc-finger transcription factors that regulate various developmental processes, such as haematopoiesis and cardiovascular development. In zebrafish, transient knockdown analysis of biklf/klf17 using antisense morpholino suggests the involvement of biklf/klf17 in primitive erythropoiesis and hatching gland development; however, the continuous physiological importance of klf17 remains uncharacterized under the genetic ablation of the klf17 gene among vertebrates. We established the klf17-disrupted zebrafish lines using the CRISPR/Cas9 technology and performed phenotypic analysis throughout early embryogenesis. We found that the klf17-deficient embryos exhibited abnormal lateral line Neuromast deposition, whereas the production of primitive erythrocytes and haemoglobin production were observed in the klf17-deficient embryos. The expression of lateral line Neuromast genes, klf17 and s100t, in the klf17-deficient embryos was detected in posterior lateral line Neuromasts abnormally positioned at short intervals. Furthermore, the klf17-deficient embryos failed to hatch and died without hatching around 15 days post-fertilization (dpf), whereas the dechorionated klf17-deficient embryos and wild-type embryos were alive at 15 dpf. The klf17-deficient embryos abolished hatching gland cells and Ctsl1b protein expression, and eliminated the expression of polster and hatching gland marker genes, he1.1, ctsl1b and cd63. Thus, the klf17 gene plays important roles in posterior lateral line Neuromast and hatching gland development.
-
characterization of biklf klf17 deficient zebrafish in posterior lateral line Neuromast and hatching gland development
Scientific Reports, 2019Co-Authors: Hiroaki Suzuki, Tomoe Ishizaka, Kanoko Yanagi, Ryota Sone, Yuto Sunaga, Rie Ohga, Atsuo KawaharaAbstract:Krupple-like factors (Klfs) are highly conserved zinc-finger transcription factors that regulate various developmental processes, such as haematopoiesis and cardiovascular development. In zebrafish, transient knockdown analysis of biklf/klf17 using antisense morpholino suggests the involvement of biklf/klf17 in primitive erythropoiesis and hatching gland development; however, the continuous physiological importance of klf17 remains uncharacterized under the genetic ablation of the klf17 gene among vertebrates. We established the klf17-disrupted zebrafish lines using the CRISPR/Cas9 technology and performed phenotypic analysis throughout early embryogenesis. We found that the klf17-deficient embryos exhibited abnormal lateral line Neuromast deposition, whereas the production of primitive erythrocytes and haemoglobin production were observed in the klf17-deficient embryos. The expression of lateral line Neuromast genes, klf17 and s100t, in the klf17-deficient embryos was detected in posterior lateral line Neuromasts abnormally positioned at short intervals. Furthermore, the klf17-deficient embryos failed to hatch and died without hatching around 15 days post-fertilization (dpf), whereas the dechorionated klf17-deficient embryos and wild-type embryos were alive at 15 dpf. The klf17-deficient embryos abolished hatching gland cells and Ctsl1b protein expression, and eliminated the expression of polster and hatching gland marker genes, he1.1, ctsl1b and cd63. Thus, the klf17 gene plays important roles in posterior lateral line Neuromast and hatching gland development.