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Methanol Skin Mucus Extract of Mrigal (Cirrhinus mrigala) Fish Peptide Targeting Viral Particles of Infectious Pancreatic Necrosis Virus (IPNV) and Infectious Salmon Anemia Virus (ISAV): an in silico Approach. Int J Pept Res Ther 2021. [DOI: 10.1007/s10989-021-10179-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Jain G, Starksen M, Singh K, Hoang C, Yancey P, McCord C, Fudge DS. High concentrations of trimethylamines in slime glands inhibit skein unraveling in Pacific hagfish. ACTA ACUST UNITED AC 2019; 222:jeb.213793. [PMID: 31672730 DOI: 10.1242/jeb.213793] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 10/28/2019] [Indexed: 11/20/2022]
Abstract
Hagfish defend themselves from fish predators by producing large volumes of gill-clogging slime when they are attacked. The slime consists of seawater and two major components that are ejected from the slime glands: mucus and threads. The threads are produced within specialized cells and packaged into intricately coiled bundles called skeins. Skeins are kept from unraveling via a protein adhesive that dissolves when the skeins are ejected from the slime glands. Previous work revealed that hagfish slime glands have high concentrations of methylamines including trimethylamine N-oxide (TMAO), trimethylglycine (betaine) and dimethylglycine (DMG); however, the function of these compounds in the slime glands is unknown. We hypothesized that methylamines have stabilizing effects on the skeins that prevent premature unraveling in the gland. To test this hypothesis, we quantified the effect of methylamines on skein unraveling in Pacific hagfish and found that TMAO and betaine have inhibitory effects on skein unraveling in vitro Furthermore, we found that TMAO is a more effective inhibitor of unraveling than betaine, but the presence of TMAO synergistically boosts the inhibitory action of betaine. Glycine and DMG were far less effective inhibitors of unraveling at natural concentrations. Our results support the hypothesis that high levels of trimethylamines in the slime glands may act to hold the coiled thread skeins together within gland thread cells, and they may do so by stabilizing adhesive proteins. These results advance our knowledge of skein stabilization and deployment and provide yet another example of trimethylamines functioning to stabilize proteins in a marine organism.
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Affiliation(s)
- Gaurav Jain
- Schmid College of Science and Technology, Chapman University, 1 University Dr., Orange, CA 92866, USA
| | - Marie Starksen
- Schmid College of Science and Technology, Chapman University, 1 University Dr., Orange, CA 92866, USA
| | - Kashika Singh
- Schmid College of Science and Technology, Chapman University, 1 University Dr., Orange, CA 92866, USA
| | - Christopher Hoang
- Schmid College of Science and Technology, Chapman University, 1 University Dr., Orange, CA 92866, USA
| | - Paul Yancey
- Biology Department, Whitman College, 345 Boyer Ave, Walla Walla, WA 99362, USA
| | - Charlene McCord
- Schmid College of Science and Technology, Chapman University, 1 University Dr., Orange, CA 92866, USA.,Department of Biology, California State University, Dominguez Hills, 1000 E. Victoria Street, Carson, CA 90747, USA
| | - Douglas S Fudge
- Schmid College of Science and Technology, Chapman University, 1 University Dr., Orange, CA 92866, USA
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Glover CN, Weinrauch AM. The good, the bad and the slimy: experimental studies of hagfish digestive and nutritional physiology. ACTA ACUST UNITED AC 2019; 222:222/14/jeb190470. [PMID: 31308056 DOI: 10.1242/jeb.190470] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The hagfishes provide valuable insight into the physiology of feeding, digestion and nutrient absorption by virtue of unusual and unique features of their biology. For example, members of this group undergo long periods of fasting, and are the only vertebrates known to absorb organic nutrients across their epidermal surface. Such properties engender significant attention from researchers interested in feeding and feeding-related processes; however, the practical realities of employing the hagfish as an experimental organism can be challenging. Many of the key tools of the experimental biologist are compromised by a species that does not readily feed in captivity, is difficult to instrument and which produces copious quantities of slime. This Commentary provides critical insight into the key aspects of hagfish feeding and digestive processes, and highlights the pitfalls of this group as experimental organisms. We also suggest key research gaps that, if filled, will lead to better understanding of hagfishes, and we consider how this group may advance our knowledge of feeding, digestion and nutrient absorption processes.
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Affiliation(s)
- Chris N Glover
- Athabasca River Basin Research Institute and Faculty of Science and Technology, Athabasca University, Athabasca, AB T9S 3A3, Canada .,Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Alyssa M Weinrauch
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
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Schorno S, Gillis TE, Fudge DS. Cellular mechanisms of slime gland refilling in Pacific hagfish (Eptatretus stoutii). J Exp Biol 2018; 221:jeb.183806. [DOI: 10.1242/jeb.183806] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 06/17/2018] [Indexed: 01/16/2023]
Abstract
Hagfishes use their defensive slime to ward off gill-breathing predators. Slime gland refilling is a surprisingly slow process, and previous research has shown that the composition of the slime exudate changes significantly during refilling, which likely has consequences for the functionality of the slime. This study set out to expand our understanding of slime gland refilling by examining the cellular processes involved in refilling of the glands, as well as determining where in the gland the main slime cells, the gland thread cells and gland mucous cells, arise. Slime glands were electro-stimulated to exhaust their slime stores, left to refill for set periods of time, and harvested for histological and immunohistochemical examination. Whole slime glands, gland thread cell morphometrics and slime cell proportions were examined over the refilling cycle. Slime glands decreased significantly in size after exhaustion, but steadily increased in size over refilling. Gland thread cells were the limiting factor in slime gland refilling, taking longer to replenish and mature than gland mucous cells. Newly produced gland thread cells underwent most of their growth near the edge of the gland, and larger cells were found farthest from the edge of the gland. Immunohistochemical analysis also revealed proliferating cells only within the epithelial lining of the slime gland, suggesting that new slime cells originate from undifferentiated cells lining the gland. Our results provide an in-depth look at the cellular dynamics of slime gland refilling in Pacific hagfish, and provide a model for how slime glands refill at the cellular level.
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Affiliation(s)
- Sarah Schorno
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Todd E. Gillis
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Douglas S. Fudge
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
- Schmid College of Science and Technology, Chapman University, Orange CA 92866, USA
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