Structural characteristics of the epidermis in marine and freshwater finless porpoises adapted to distinct osmotic environments Open Access.

Saved in:
Bibliographic Details
Title: Structural characteristics of the epidermis in marine and freshwater finless porpoises adapted to distinct osmotic environments Open Access.
Authors: Zhou, Haojie1,2 (AUTHOR), Zhang, Changqun3 (AUTHOR), Tang, Bin1,4 (AUTHOR), Zhang, Haobo1,2 (AUTHOR), Zheng, Jinsong1,4 (AUTHOR), Wang, Kexiong1,4 (AUTHOR), He, Dekui1 (AUTHOR), Hao, Yujiang1,4 (AUTHOR)
Source: Current Zoology. Jun2025, Vol. 71 Issue 3, p304-319. 16p.
Document Type: Article
Subjects: Epidermis, Freshwater ecology, Anatomical variation, Marine ecology, Dehydration, Cetacea, Osmoregulation, Cell morphology
Geographic Terms: Yangtze River (China)
Author-Supplied Keywords: epidermis
finless porpoise
histology
osmotic adaptation
stratum basale cells
TEWL
Abstract: The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis , Pilleri & Gihr, 1972; YFP) is an exclusively freshwater cetacean species inhabiting the Yangtze River and its connecting large lakes. As the primary line of defense in maintaining physiological equilibrium, the epidermis of the porpoise is expected to have undergone structural adaptations due to the shift from the marine to the freshwater environment. This study compared the microstructural and ultrastructural features of the epidermis of YFP and its marine counterpart, the East Asian finless porpoise (Neophocaena asiaeorientalis sunameri , Pilleri & Gihr, 1975; EAFP). Microscopic structural observations and statistical analyses of the epidermal thickness demonstrated no significant differences in the cell structure or distribution between the two porpoise species. However, the epidermis of the YFP contained more abundant stratum basale cells. The outermost lipid stratum corneum exhibited a thinner cell layer with wider neutral lipid droplets to resist the passive entry of water molecules in the hypotonic environment. In contrast, for the EAFP, a more uniformly arranged stratum basale in the epidermis led to denser keratin fibers and robust desmosomes within each epidermal layer at the ultrastructural level. This tight arrangement of cells can reduce transepidermal water loss (TEWL) in an environment with higher osmotic pressure. In conclusion, the 2 finless porpoise species appear to employ different epidermal mechanisms to adapt to their distinct osmotic environments. The YFP appears to possess a "lipid waterproofing" epidermal structure, while the EAFP possesses a "thick and compact water-retaining" epidermal structure to cope with potential water loss. [ABSTRACT FROM AUTHOR]
Copyright of Current Zoology is the property of Oxford University Press / USA and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Author Affiliations: 1Institute of Hydrobiology, Chinese Academy of Sciences, No. 7 South Donghu Road, Wuchang District, Wuhan 430072, China
2College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, No.1 Yanqihu East Rd, Huairou District, Beijing 101408, China
3Department of Marine Biology, Texas A&M University at Galveston, 200 Seawolf Pkwy, Galveston, TX 77554, USA
4National Aquatic Biological Resource Center, NABRC, No. 7 South Donghu Road, Wuchang District, Wuhan 430072, China
Full Text Word Count: 10536
ISSN: 1674-5507
DOI: 10.1093/cz/zoae049
Accession Number: 187147858
Database: Veterinary Source
Full text is not displayed to guests.
Description
Abstract:The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis , Pilleri & Gihr, 1972; YFP) is an exclusively freshwater cetacean species inhabiting the Yangtze River and its connecting large lakes. As the primary line of defense in maintaining physiological equilibrium, the epidermis of the porpoise is expected to have undergone structural adaptations due to the shift from the marine to the freshwater environment. This study compared the microstructural and ultrastructural features of the epidermis of YFP and its marine counterpart, the East Asian finless porpoise (Neophocaena asiaeorientalis sunameri , Pilleri & Gihr, 1975; EAFP). Microscopic structural observations and statistical analyses of the epidermal thickness demonstrated no significant differences in the cell structure or distribution between the two porpoise species. However, the epidermis of the YFP contained more abundant stratum basale cells. The outermost lipid stratum corneum exhibited a thinner cell layer with wider neutral lipid droplets to resist the passive entry of water molecules in the hypotonic environment. In contrast, for the EAFP, a more uniformly arranged stratum basale in the epidermis led to denser keratin fibers and robust desmosomes within each epidermal layer at the ultrastructural level. This tight arrangement of cells can reduce transepidermal water loss (TEWL) in an environment with higher osmotic pressure. In conclusion, the 2 finless porpoise species appear to employ different epidermal mechanisms to adapt to their distinct osmotic environments. The YFP appears to possess a "lipid waterproofing" epidermal structure, while the EAFP possesses a "thick and compact water-retaining" epidermal structure to cope with potential water loss. [ABSTRACT FROM AUTHOR]
ISSN:16745507
DOI:10.1093/cz/zoae049