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Mauel C, Leicht L, Broshko Y, Yaryhin O, Werneburg I. Chondrocranial anatomy of Testudo hermanni (Testudinidae, Testudines) with a comparison to other turtles. J Morphol 2024; 285:e21747. [PMID: 38956884 DOI: 10.1002/jmor.21747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 06/04/2024] [Accepted: 06/05/2024] [Indexed: 07/04/2024]
Abstract
Using histological cross-sections, the chondrocranium anatomy was reconstructed for two developmental stages of Hermann's tortoise (Testudo hermanni). The morphology differs from the chondrocrania of most other turtles by a process above the ectochoanal cartilage with Pelodiscus sinensis being the only other known species with such a structure. The anterior and posterior processes of the tectum synoticum are better developed than in most other turtles and an ascending process of the palatoquadrate is missing, which is otherwise only the case in pleurodiran turtles. The nasal region gets proportionally larger during development. We interpret the enlargement of the nasal capsules as an adaption to increase the surface area of the olfactory epithelium for better perception of volant odors. Elongation of the nasal capsules in trionychids, in contrast, is unlikely to be related to olfaction, while it is ambiguous in the case of Sternotherus odoratus. However, we have to conclude that research on chondrocranium anatomy is still at its beginning and more comprehensive detailed descriptions in relation to other parts of the anatomy are needed before providing broad-scale ecological and phylogenetic interpretations.
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Affiliation(s)
- Carola Mauel
- Fachbereich Biologie, Universität Tübingen, Tübingen, Germany
- Steinmann-Institut für Geologie, Mineralogie und Paläontologie, Universität Bonn, Bonn, Germany
| | - Luca Leicht
- Fachbereich Biologie, Universität Tübingen, Tübingen, Germany
- Senckenberg Center for Human Evolution and Palaeoenvironment (SHEP), Universität Tübingen, Tübingen, Germany
| | - Yevhenii Broshko
- Faculty of Natural Sciences, Faculty of Natural Sciences, Kryvyi Rih State Pedagogical University, Kryvyi Rih, Ukraine
| | - Oleksandr Yaryhin
- Schmalhausen Institute of Zoology NAS of Ukraine, Department of Evolutionary Morphology, Kyiv, Ukraine
| | - Ingmar Werneburg
- Senckenberg Center for Human Evolution and Palaeoenvironment (SHEP), Universität Tübingen, Tübingen, Germany
- Fachbereich Geowissenschaften, Universität Tübingen, Tübingen, Germany
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2
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Nakamuta S, Itoh M, Mori M, Kurita M, Zhang Z, Nikaido M, Miyazaki M, Yokoyama T, Yamamoto Y, Nakamuta N. In situ hybridization analysis of odorant receptor expression in the olfactory organ of the pig-nosed turtle Carettochelys insculpta. Tissue Cell 2023; 85:102255. [PMID: 37922676 DOI: 10.1016/j.tice.2023.102255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 10/19/2023] [Accepted: 10/20/2023] [Indexed: 11/07/2023]
Abstract
The turtle olfactory organ consists of upper (UCE) and lower (LCE) chamber epithelium, which send axons to the ventral and dorsal portions of the olfactory bulbs, respectively. Generally, the UCE is associated with glands and contains ciliated olfactory receptor neurons (ORNs), while the LCE is devoid of glands and contains microvillous ORNs. However, the olfactory organ of the pig-nosed turtle Carettochelys insculpta appears to be a single olfactory system morphologically: there are no associated glands; ciliated ORNs are distributed throughout the olfactory organ; and the olfactory bulb is not divided into ventral and dorsal portions. In this study, we analyzed the expression of odorant receptors (ORs), the major olfactory receptors in turtles, in the pig-nosed turtle olfactory organ, via in situ hybridization. Of 690 ORs, 375 were classified as class I and 315 as class II. Some class II ORs were expressed predominantly in the posterior dorsomedial walls of the nasal cavity, while other class II ORs and all class I ORs examined were expressed in the remaining region. These results suggest that the pig-nosed turtle olfactory organ can be divided into two regions according to the expression of ORs.
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Affiliation(s)
- Shoko Nakamuta
- Laboratory of Veterinary Anatomy, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan
| | - Miho Itoh
- Port of Nagoya Public Aquarium, 1-3 Minato-machi, Minato-ku, Nagoya, Aichi 455-0033, Japan
| | - Masanori Mori
- Port of Nagoya Public Aquarium, 1-3 Minato-machi, Minato-ku, Nagoya, Aichi 455-0033, Japan
| | - Masanori Kurita
- Port of Nagoya Public Aquarium, 1-3 Minato-machi, Minato-ku, Nagoya, Aichi 455-0033, Japan
| | - Zicong Zhang
- Institute for the Advanced Study of Human Biology, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Masato Nikaido
- School of Life Science and Technology, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Masao Miyazaki
- Department of Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan
| | - Takuya Yokoyama
- Laboratory of Veterinary Anatomy, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan
| | - Yoshio Yamamoto
- Laboratory of Veterinary Anatomy, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan
| | - Nobuaki Nakamuta
- Laboratory of Veterinary Anatomy, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan.
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3
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Nakamuta N, Nakamuta S, Yamamoto Y, Kato H. Morphological Analysis of the Olfactory System of the Pig-Nosed Turtle, Carettochelys insculpta. Zoolog Sci 2023; 40:463-467. [PMID: 38064373 DOI: 10.2108/zs220100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 03/07/2023] [Indexed: 12/18/2023]
Abstract
The turtle olfactory organ consists of the upper (UCE) and lower (LCE) chamber epithelium, projecting to the ventral and dorsal parts of the olfactory bulbs, respectively. The UCE is associated with glands, contains ciliated olfactory receptor neurons, and is assumed to detect odorants primarily in air, while the LCE is devoid of glands, contains microvillous olfactory receptor neurons, and is assumed to detect odorants primarily in water. Examining the olfactory system of the pig-nosed turtle, Carettochelys insculpta, this study found that both the upper and lower chambers of the nasal cavity were lined with sensory epithelium devoid of associated glands and contained ciliated olfactory receptor neurons. Moreover, the olfactory bulbs were not divided into dorsal and ventral parts. These results suggest that the olfactory system of the pig-nosed turtle is a single system specialized for detecting odorants in water.
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Affiliation(s)
- Nobuaki Nakamuta
- Laboratory of Veterinary Anatomy, Iwate University, Morioka, Iwate 020-8550, Japan,
| | - Shoko Nakamuta
- Laboratory of Veterinary Anatomy, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Yoshio Yamamoto
- Laboratory of Veterinary Anatomy, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Hideaki Kato
- Faculty of Education, Shizuoka University, Shizuoka 422-8529, Japan
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4
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Nakamuta S, Noda H, Kato H, Yokoyama T, Yamamoto Y, Nakamuta N. Expression patterns of the transcription factors Fezf1, Fezf2, and Bcl11b in the olfactory organs of turtle embryos. J Morphol 2023; 284:e21655. [PMID: 37856277 DOI: 10.1002/jmor.21655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 10/09/2023] [Indexed: 10/21/2023]
Abstract
Many tetrapod vertebrates have two distinct olfactory organs, the olfactory epithelium (OE) and vomeronasal organ (VNO). In turtles, the olfactory organ consists of two types of sensory epithelia, the upper chamber epithelium (UCE; corresponding to the OE) and the lower chamber epithelium (LCE; corresponding to the VNO). In many turtle species, the UCE contains ciliated olfactory receptor cells (ORCs) and the LCE contains microvillous ORCs. To date, several transcription factors involved in the development of the OE and VNO have been identified in mammals. Fez family zinc-finger protein 1 and 2 (Fezf1 and 2) are expressed in the OE and VNO, respectively, of mouse embryos, and are involved in the development and maintenance of ORCs. B-cell lymphoma/leukemia 11B (Bcl11b) is expressed in the mouse embryo OE except the dorsomedial parts of the nasal cavity, and regulates the expression of odorant receptors in the ORCs. In this study, we examined the expression of Fezf1, Fezf2, and Bcl11b in the olfactory organs of embryos in three turtle species, Pelodiscus sinensis, Trachemys scripta elegans, and Centrochelys sulcata, to evaluate their involvement in the development of reptile olfactory organs. In all three turtle species, Bcl11b was expressed in the UCE, Fezf2 in the LCE, and Fezf1 in both the UCE and LCE. These results imply that the roles of the transcription factors Fezf1, Fezf2, and Bcl11b in olfactory organ development are conserved among mammals and turtles.
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Affiliation(s)
- Shoko Nakamuta
- Laboratory of Veterinary Anatomy, Iwate University, Morioka, Japan
| | | | - Hideaki Kato
- Faculty of Education, Shizuoka University, Shizuoka, Japan
| | - Takuya Yokoyama
- Laboratory of Veterinary Anatomy, Iwate University, Morioka, Japan
| | - Yoshio Yamamoto
- Laboratory of Veterinary Anatomy, Iwate University, Morioka, Japan
| | - Nobuaki Nakamuta
- Laboratory of Veterinary Anatomy, Iwate University, Morioka, Japan
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5
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Kondoh D, Kaneoya Y, Tonomori W, Kitayama C. Histological features and Gα olf expression patterns in the nasal cavity of sea turtles. J Anat 2023; 243:486-503. [PMID: 37042468 PMCID: PMC10439381 DOI: 10.1111/joa.13873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 03/23/2023] [Accepted: 03/27/2023] [Indexed: 04/13/2023] Open
Abstract
Sea turtles use olfaction to detect volatile and water-soluble substances. The nasal cavity of green turtles (Chelonia mydas) comprises morphologically defined the anterodorsal, anteroventral, and posterodorsal diverticula, as well as a single posteroventral fossa. Here, we detailed the histological features of the nasal cavity of a mature female green turtle. The posterodorsal diverticulum contained spongy-like venous sinuses and a wave-shaped sensory epithelium that favored ventilation. Secretory structures that were significant in sensory and non-sensory epithelia were probably involved in protection against seawater. These findings suggested that green turtles efficiently intake airborne substances and dissolve water-soluble substances in mucous, while suppressing the effects of salts. In addition, positive staining of Gαs/olf that couples with olfactory, but not vomeronasal, receptors was predominant in all three types of sensory epithelium in the nasal cavity. Both of airborne and water-soluble odorants seemed to be detected in cells expressing Gαolf and olfactory receptors.
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Affiliation(s)
- Daisuke Kondoh
- Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Yuka Kaneoya
- Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Wataru Tonomori
- Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Chiyo Kitayama
- Everlasting Nature of Asia (ELNA), Yokohama, Kanagawa, Japan
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6
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Nakamuta S, Mori M, Ito M, Kurita M, Miyazaki M, Yamamoto Y, Nakamuta N. In situ hybridization analysis of olfactory receptor expression in the sea turtle olfactory organ. Cell Tissue Res 2023:10.1007/s00441-023-03782-6. [PMID: 37266727 DOI: 10.1007/s00441-023-03782-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 05/08/2023] [Indexed: 06/03/2023]
Abstract
The olfactory organ of turtles consists of an upper chamber epithelium (UCE) with associated glands, and a lower chamber epithelium (LCE) devoid of glands. The UCE and LCE are referred to as the air-nose and the water-nose, respectively, because the UCE is thought to detect airborne odorants, while the LCE detects waterborne odorants. However, it is not clear how the two are used in the olfactory organ. Odorant receptors (ORs) are the major olfactory receptors in turtles; they are classified as class I and II ORs, distinguished by their primary structure. Class I ORs are suggested to be receptive to water-soluble ligands and class II ORs to volatile ligands. This study analyzed the expression of class I and II ORs in hatchlings of the green sea turtle, Chelonia mydas, through in situ hybridization, to determine the localization of OR-expressing cells in the olfactory organ. Class I OR-expressing cells were distributed mainly in the LCE, implying that the LCE is receptive to waterborne odorants. Class II OR-expressing cells were distributed in both the UCE and LCE, implying that the entire olfactory organ is receptive to airborne odorants. The widespread expression of class II ORs may increase opportunities for sea turtles to sense airborne odorants.
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Affiliation(s)
- Shoko Nakamuta
- Laboratory of Veterinary Anatomy, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate, 020-8550, Japan
| | - Masanori Mori
- Port of Nagoya Public Aquarium, 1-3 Minato-machi, Minato-ku, Nagoya, Aichi, 455-0033, Japan
| | - Miho Ito
- Port of Nagoya Public Aquarium, 1-3 Minato-machi, Minato-ku, Nagoya, Aichi, 455-0033, Japan
| | - Masanori Kurita
- Port of Nagoya Public Aquarium, 1-3 Minato-machi, Minato-ku, Nagoya, Aichi, 455-0033, Japan
| | - Masao Miyazaki
- Department of Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate, 020-8550, Japan
| | - Yoshio Yamamoto
- Laboratory of Veterinary Anatomy, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate, 020-8550, Japan
| | - Nobuaki Nakamuta
- Laboratory of Veterinary Anatomy, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate, 020-8550, Japan.
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7
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Kondoh D, Kitayama C, Yamaguchi Y, Yanagawa M, Kawai YK, Suzuki C, Itakura R, Fujimoto A, Satow T, Kondo S, Sato T. Nasal Cavity of Green Sea Turtles Contains 3 Independent Sensory Epithelia. Chem Senses 2020; 44:427-434. [PMID: 31155674 DOI: 10.1093/chemse/bjz033] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The morphological and histological features of the nasal cavity are diverse among animal species, and the nasal cavities of terrestrial and semiaquatic turtles possess 2 regions lined with each different type of sensory epithelium. Sea turtles can inhale both of volatile and water-soluble odorants with high sensitivity, but details of the architectural features and the distribution of the sensory epithelia within the sea turtle nasal cavity remain uncertain. The present study analyzed the nasal cavity of green sea turtles using morphological, computed tomographic, and histological methods. We found that the middle region of the sea turtle nasal cavity is divided into anterodorsal, anteroventral, and posterodorsal diverticula and a posteroventral excavation by connective tissue containing cartilages. The posterodorsal diverticulum was lined with a thin sensory epithelium, and the anterodorsal and anteroventral diverticula were occupied by a single thick sensory epithelium. In addition, a relatively small area on the posteroventral excavation was covered by independent sensory epithelium that differed from other 2 types of epithelia, and a single thin bundle derived from the posteroventral excavation comprised the most medial nerve that joins the anterior end of the olfactory nerve tract. These findings suggested that the posteroventral excavation identified herein transfers stimuli through an independent circuit and plays different roles when odorants arise from other nasal regions.
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Affiliation(s)
- Daisuke Kondoh
- Laboratory of Veterinary Anatomy, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho Nishi, Obihiro, Hokkaido, Japan
| | - Chiyo Kitayama
- Everlasting Nature of Asia (ELNA), Ogasawara Marine Center, Chichi-Jima Byobudani, Ogasawara, Tokyo, Japan
| | - Yohei Yamaguchi
- Laboratory of Veterinary Anatomy, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho Nishi, Obihiro, Hokkaido, Japan
| | - Masashi Yanagawa
- Department of Applied Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho Nishi, Obihiro, Hokkaido, Japan
| | - Yusuke K Kawai
- Laboratory of Toxicology, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho Nishi, Obihiro, Hokkaido, Japan
| | - Chihiro Suzuki
- Laboratory of Veterinary Anatomy, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho Nishi, Obihiro, Hokkaido, Japan
| | - Raito Itakura
- Laboratory of Veterinary Anatomy, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho Nishi, Obihiro, Hokkaido, Japan
| | - Atsuru Fujimoto
- Division of Environmental and Agricultural Engineering, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho Nishi, Obihiro, Hokkaido, Japan
| | - Tadatoshi Satow
- Division of Environmental and Agricultural Engineering, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho Nishi, Obihiro, Hokkaido, Japan
| | - Satomi Kondo
- Everlasting Nature of Asia (ELNA), Ogasawara Marine Center, Chichi-Jima Byobudani, Ogasawara, Tokyo, Japan
| | - Takayuki Sato
- Everlasting Nature of Asia (ELNA), Ogasawara Marine Center, Chichi-Jima Byobudani, Ogasawara, Tokyo, Japan
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Abdali SS, Nakamuta S, Yamamoto Y, Nakamuta N. Distribution of cells expressing vomeronasal receptors in the olfactory organ of turtles. J Vet Med Sci 2020; 82:1068-1079. [PMID: 32727968 PMCID: PMC7468070 DOI: 10.1292/jvms.20-0207] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Generally, the olfactory organ of vertebrates consists of the olfactory epithelium (OE)
and the vomeronasal organ (VNO). The OE contains ciliated olfactory receptor neurons
(ORNs), while the VNO contains microvillous ORNs. The ORNs in the OE express odorant
receptors (ORs), while those in the VNO express type 1 and type 2
vomeronasal receptors (V1Rs and V2Rs). In turtles, the
olfactory organ consists of the upper (UCE) and lower chamber epithelia (LCE). The UCE
contains ciliated ORNs, while the LCE contains microvillous ORNs. Here we investigated the
distribution of cells expressing vomeronasal receptors in the olfactory organ of turtles.
The turtle vomeronasal receptors were encoded by two V1R genes and two
V2R genes. Among them, V2R1 and V2R26
were mainly expressed in the LCE, while V1R3 was expressed both in the
UCE and LCE. Notably, vomeronasal receptors were expressed by a limited number of ORNs,
which was confirmed by the expression of the gene encoding TRPC2, an ion channel involved
in the signal transduction of vomeronasal receptors. Furthermore, expression of
ORs by the majority of ORNs was suggested by the expression of the gene
encoding CNGA2, an ion channel involved in the signal transduction of ORs. Thus, olfaction
of turtle seems to be mediated mainly by the ORs rather than the vomeronasal receptors.
More importantly, the relationship between the fine structure of ORNs and the expression
of olfactory receptors are not conserved among turtles and other vertebrates.
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Affiliation(s)
- Sayed Sharif Abdali
- United Graduate School of Veterinary Sciences, Gifu University, Gifu 501-1193, Japan.,Laboratory of Veterinary Anatomy, Faculty of Agriculture, Iwate University, Morioka 020-8550, Japan
| | - Shoko Nakamuta
- Laboratory of Veterinary Anatomy, Faculty of Agriculture, Iwate University, Morioka 020-8550, Japan
| | - Yoshio Yamamoto
- United Graduate School of Veterinary Sciences, Gifu University, Gifu 501-1193, Japan.,Laboratory of Veterinary Anatomy, Faculty of Agriculture, Iwate University, Morioka 020-8550, Japan
| | - Nobuaki Nakamuta
- United Graduate School of Veterinary Sciences, Gifu University, Gifu 501-1193, Japan.,Laboratory of Veterinary Anatomy, Faculty of Agriculture, Iwate University, Morioka 020-8550, Japan
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9
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Yamaguchi Y, Kitayama C, Tanaka S, Kondo S, Miyazaki A, Okamoto K, Yanagawa M, Kondoh D. Computed tomographic analysis of internal structures within the nasal cavities of green, loggerhead and leatherback sea turtles. Anat Rec (Hoboken) 2020; 304:584-590. [PMID: 32478454 DOI: 10.1002/ar.24469] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 04/04/2020] [Accepted: 04/20/2020] [Indexed: 11/07/2022]
Abstract
The morphology of the tetrapod nasal cavity has adapted to the environment in terms of olfaction and respiration. Reports indicate that the internal structure of the nasal cavity of green sea turtles is more complex than that of turtles in general, but whether or not it is similar among sea turtle species remains unknown. The present study aimed to define the internal structures of the nasal cavity of green (Chelonian mydas), loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtles using computed tomography. The nasal cavity of green and loggerhead sea turtles contained anterodorsal, anteroventral, posterodorsal diverticula and a posteroventral excavation in the middle. In contrast, the nasal cavity of leatherback sea turtles had more complicated dorsal region comprising anterodorsal and posterodorsal diverticula, and two excavations between the nostril and anterodorsal diverticulum, but no distinct structures at the ventral region. The airway in the nasal cavity was shorter and thicker in the leatherback, than in the green and loggerhead turtles. These species differences might reflect ecological variety and different evolutionary strategies.
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Affiliation(s)
- Yohei Yamaguchi
- Laboratory of Veterinary Anatomy, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan
| | - Chiyo Kitayama
- Everlasting Nature of Asia (ELNA), Ogasawara Marine Center, Tokyo, Japan
| | | | - Satomi Kondo
- Everlasting Nature of Asia (ELNA), Ogasawara Marine Center, Tokyo, Japan
| | - Ayano Miyazaki
- Laboratory of Veterinary Anatomy, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan
| | - Kei Okamoto
- Tuna Fisheries Resources Group, National Research Institute of Far Seas Fisheries, Japan Fisheries Research and Education Agency, Shizuoka, Japan
| | - Masashi Yanagawa
- Department of Applied Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan
| | - Daisuke Kondoh
- Laboratory of Veterinary Anatomy, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan
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10
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Kondoh D, Kitayama C, Aiko Y, Yamaguchi Y. Main airway throughout the nasal cavity of green sea turtles is lined by keratinized stratified squamous epithelium. Tissue Cell 2020; 65:101370. [PMID: 32746990 DOI: 10.1016/j.tice.2020.101370] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/15/2020] [Accepted: 04/15/2020] [Indexed: 11/19/2022]
Abstract
Structural and histological features of the nasal cavity of sea turtles are largely different from those of other Testudines species. The sea turtle nasal cavity is a pair of tubular structures with three diverticula and an excavation in the center, and three types of sensory epithelium are present in these four significant structures. To more clarify the adaptation of the nasal cavity to marine life style in sea turtles, non-sensory epithelium in the nasal cavity of green sea turtles (Chelonia mydas) were histologically determined from nostril to choanae in this study. Unlike many other animals including terrestrial turtles, the vestibular area and nasopharyngeal duct were all lined by keratinized stratified squamous epithelium. In the main nasal cavity, the margins of each sensory epithelium turned into respiratory epithelium with goblet cells, followed by keratinized stratified squamous epithelium. Keratinized epithelium appears more appropriate in sea turtle upper airway to protect against osmotic pressure when they release seawater through the nostrils, and thus this histological feature of upper airway might reflect adaptation to marine life style.
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Affiliation(s)
- Daisuke Kondoh
- Laboratory of Veterinary Anatomy, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
| | - Chiyo Kitayama
- Everlasting Nature of Asia (ELNA), Ogasawara Marine Center, Ogasawara, Tokyo 100-2101, Japan
| | - Yuki Aiko
- Laboratory of Veterinary Anatomy, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan
| | - Yohei Yamaguchi
- Laboratory of Veterinary Anatomy, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan
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11
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Abdali SS, Kurasawa K, Nakamuta S, Yamamoto Y, Nakamuta N. Number of olfactory receptor neurons in the Chinese soft-shelled turtle. J Vet Med Sci 2017; 79:1569-1572. [PMID: 28781329 PMCID: PMC5627330 DOI: 10.1292/jvms.17-0326] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The olfactory organ of turtle consists of the upper chamber epithelium (UCE) and the lower chamber epithelium (LCE), detecting air-borne odorants and water-borne odorants, respectively. In this study, we investigated the number
of olfactory receptor neurons (ORNs) in the UCE and LCE of soft-shelled turtle in order to find their possible differences among terrestrial, semi-aquatic and highly-aquatic turtles. The number of ORNs in the soft-shelled turtle
was higher in the LCE than in the UCE, suggesting its close relationship to the environment the turtle lives. In addition, relative abundance of the ORNs in the LCE to the UCE varied in accordance with the size of individuals,
although its functional significance remains elusive.
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Affiliation(s)
- Sayed Sharif Abdali
- United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1193, Japan
| | - Kouki Kurasawa
- Laboratory of Veterinary Anatomy, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan
| | - Shoko Nakamuta
- Laboratory of Veterinary Anatomy, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan
| | - Yoshio Yamamoto
- United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1193, Japan.,Laboratory of Veterinary Anatomy, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan
| | - Nobuaki Nakamuta
- United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1193, Japan.,Laboratory of Veterinary Anatomy, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan
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