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Scadeng M, McKenzie C, He W, Bartsch H, Dubowitz DJ, Stec D, St. Leger J. Morphology of the Amazonian Teleost Genus Arapaima Using Advanced 3D Imaging. Front Physiol 2020; 11:260. [PMID: 32395105 PMCID: PMC7197331 DOI: 10.3389/fphys.2020.00260] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 03/06/2020] [Indexed: 11/13/2022] Open
Abstract
The arapaima is the largest of the extant air-breathing freshwater fishes. Their respiratory gas bladder is arguably the most striking of all the adaptations to living in the hypoxic waters of the Amazon basin, in which dissolved oxygen can reach 0 ppm (0 mg/l) at night. As obligatory air-breathers, arapaima have undergone extensive anatomical and physiological adaptations in almost every organ system. These changes were evaluated using magnetic resonance and computed tomography imaging, gross necropsy, and histology to create a comprehensive morphological assessment of this unique fish. Segmentation of advanced imaging data allowed for creation of anatomically accurate and quantitative 3D models of organs and their spatial relationships. The deflated gas bladder [1.96% body volume (BV)] runs the length of the coelomic cavity, and encompasses the kidneys (0.35% BV). It is compartmentalized by a highly vascularized webbing comprising of ediculae and inter-edicular septa lined with epithelium acting as a gas exchange surface analogous to a lung. Gills have reduced surface area, with severe blunting and broadening of the lamellae. The kidneys are not divided into separate regions, and have hematopoietic and excretory tissue interspersed throughout. The heart (0.21% BV) is encased in a thick layer of lipid rich tissue. Arapaima have an unusually large telencephalon (28.3% brain volume) for teleosts. The characteristics that allow arapaima to perfectly exploit their native environment also make them easy targets for overfishing. In addition, their habitat is at high risk from climate change and anthropogenic activities which are likely to result is fewer specimens living in the wild, or achieving their growth potential of up to 4.5 m in length.
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Affiliation(s)
- Miriam Scadeng
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
- Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | | | - Weston He
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
- NOVA Southeastern University, Fort Lauderdale, FL, United States
| | - Hauke Bartsch
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
- Mohn Medical Imaging and Visualization Centre, Haukeland University Hospital, Bergen, Norway
| | - David J. Dubowitz
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
- Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Dominik Stec
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
| | - Judy St. Leger
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
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Arunima, Mistri A, Kumari U, Mittal S, Mittal AK. Modifications in the gills of hill stream Moth catfish, Hara hara (Erethistidae, Siluriformes): A light and scanning electron microscope investigation. Tissue Cell 2019; 62:101317. [PMID: 32433019 DOI: 10.1016/j.tice.2019.101317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 10/04/2019] [Accepted: 11/12/2019] [Indexed: 11/26/2022]
Abstract
Present study reports significant modifications in surface ultrastructure, histological organization, and histochemical localization of glycoproteins (GPs) in the gills of a hill stream catfish, Hara hara. Punctate microridges on free surface of epithelial cells covering gill arches, gill rakers, gill filaments and secondary lamellae are considered to provide adaptive plasticity to gills in relation to the environment inhabited by fish. Short and stout gill rakers are considered to prevent food particles to pass in opercular chamber along with respiratory current that could damage delicate gill filaments. Mucous goblet cells show presence of different classes of glycoproteins. GPs with oxidizable vicinal diols are considered to control acidity of acidic GPs. GPs with carboxyl groups have been implicated with defensive mechanism against microorganisms. GPs with O-sulphate esters are associated to trap and to lubricate food particles for easy swallowing. Taste buds on gill arches and gill rakers function to select palatable food particles. Occurrence of taste buds on the gill filaments is regarded significant adaptation to analyse the chemical nature of water. This study could play a significant role to understand adjustment of gills in the hill stream fish.
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Affiliation(s)
- Arunima
- Skin Physiology Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221 005, India; Zoology Section, Mahila Mahavidyalaya, Banaras Hindu University, Varanasi, 221 005, India
| | - Arup Mistri
- Skin Physiology Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221 005, India
| | - Usha Kumari
- Skin Physiology Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221 005, India; Zoology Section, Mahila Mahavidyalaya, Banaras Hindu University, Varanasi, 221 005, India.
| | - Swati Mittal
- Skin Physiology Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221 005, India.
| | - Ajay Kumar Mittal
- Skin Physiology Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221 005, India.
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