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1
Lim, Jeanette Li Li. "Kinematics and Hydrodynamics of Undulatory Locomotion in Hagfishes (Myxinidae) and Hagfish-like Robotic Models." Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:10883.
Full textAbstract:
Hagfishes have both intrigued and confused biologists since Linnaeus first mistakenly classified one as an "intestinal worm." Modern hagfishes (Myxinidae) are elongate, marine fishes often described by what they lack: jaws, scales, paired fins, or a vertebral column. Accompanying this reduced morphology was a long-held view that hagfish are lazy animals that mostly lay about on the ocean floor, but more recent research has revealed them to be active hunters and scavengers in the benthic community. Routine swimming is a requisite part of these activities, yet knowledge of how these exceptionally flexible fishes swim is limited. Here, I use an integrative experimental approach to provide a more comprehensive, quantitative understanding of locomotory mechanisms in hagfishes. In Chapters 1 and 2, I use high-speed videography to quantify whole-body kinematics of steady and unsteady swimming in Eptatretus stoutii and Myxine glutinosa, representing the two main lineages within Myxinidae. Both species generally swim with high amplitude head movements and use tail beat frequency to control swim speed, but inter- and intra-specific variation in other undulatory wave variables suggests multiple mechanisms to modulate speed. Changes in the shape of the body wave characterize the observed unsteady swimming behaviors. During positive linear accelerations, hagfish transiently adopt a larger, longer body wave. During lateral maneuvers, hagfish approximate “sidewinding” behavior as anterior body regions interact with the substrate while posterior body regions propagate waves of lateral bending toward the tail tip. Chapter 3 integrates kinematics with hydrodynamics, using particle image velocimetry to visualize the flow field around swimming E. stoutii. The steady swimming wake consists of caudolateral fluid jets, which turn caudally during linear accelerations. Wake jets orient asymmetrically during lateral swimming, contributing both forward and lateral thrust over a complete tail beat. The hydrodynamic patterns observed reinforce kinematics-based hypotheses on how hagfishes enact their various swimming behaviors. In Chapter 4, I use simple robotically-controlled physical models to examine functional relationships between body flexural stiffness, shape, kinematics, hydrodynamics, and swimming performance. I relate model swim performance to characteristics of hagfish swimming, and describe lessons that passively undulating models impart for understanding locomotion by live elongate undulatory swimmers.
2
Wilson, Christopher Mark. "Cardiac control in the Pacific hagfish (Eptatretus stoutii)." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/50915.
Full textAbstract:
The Pacific hagfish (Eptatretus stoutii), being an extant ancestral craniate, possesses the most ancestral craniate-type heart with valved chambers, a response to increased filling pressure with increased stroke volume (Frank-Starling mechanism), and myogenic contractions. Unlike all other known craniate hearts, this heart receives no direct neural stimulation. Despite this, heart rate can vary four-fold during a prolonged, 36-h anoxic challenge followed by a normoxic recovery period, with heart rate decreasing in anoxia, and increasing beyond routine rates during recovery, a remarkable feat for an aneural heart. This thesis is a study of how the hagfish can regulate heart rate without the assistance of neural stimulation.
A major role of hyperpolarization-activated cyclic nucleotide-activated (HCN) channels in heartbeat initiation was indicated by pharmacological application of zatebradine to spontaneously contracting, isolated hearts, which stopped atrial contraction and vastly reduced ventricular contraction. Tetrodotoxin inhibition of voltage-gated Na⁺ channels induced an atrioventricular block suggesting these channels play a role in cardiac conduction.
Partial cloning of HCN channel mRNA extracted from hagfish hearts revealed six HCN isoforms, two hagfish representatives of vertebrate HCN2 (HCN2a and HCN2b), three of HCN3 (HCN3a, HCN3b and HCN3c) and one HCN4. Two paralogs of HCN3b were discovered, however, HCN3a dominated the expression of HCN isoforms followed by HCN4. All HCN isoforms bar HCN3b were dominantly expressed in the atrium, likely to support greater atrial excitability ensuring synchronous contractions. Phylogenetic analysis suggested that HCN3 is the ancestral isoform supporting previous observations.
Studies with β-adrenoreceptor agonists and antagonists in isolated, spontaneously beating hearts showed that the routine normoxic heart rate may involve maximal catecholamine stimulation of heart rate through cAMP stimulation of HCN channels via transmembrane adenylyl cyclase (tmAC). Loss of this tonic β-adrenorecptor cardiac stimulation during anoxia reduces heart rate, but restoring β-adrenoreceptor stimulation during normoxic recovery does not produce the previously observed increase above routine heart rate in vivo. Instead, bicarbonate-stimulated, soluble adenylyl cyclase (sAC) mediated cAMP production was found to produce this tachycardia in addition to the reinstated tmAC produced cAMP. This is the first time sAC has been implicated in heart rate control.Science, Faculty of
Zoology, Department of
Graduate
3
Cox, Georgina Kimberly. "Anoxic survival and cardiovascular responses of the pacific hagfish, Eptatretus stoutii." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/22826.
Full textAbstract:
To determine if anoxic survival in the Pacific hagfish (Eptatretus stoutii L) is aided by the suppression of metabolic rate, excess post-anoxic oxygen consumption (EPAOC) and key metabolites in the glycolytic pathway were analyzed following anoxic exposures of different durations. As the cardiovascular system reflects the needs of the tissue and thus whole animal metabolic rate, cardiac performance during prolonged anoxia was also examined to gain insight into the anoxic cardiac ATP turnover rate.
Hagfish survived 36-h exposure of complete anoxia at 10°C but showed 50% mortality if exposed to anoxia for 48 h. In order to determine if there had been metabolic rate suppression, changes in tissue metabolites were measured during 36 h anoxia exposure and EPAOC was monitored using respirometry. Analysis of EPAOC measurements suggest that hagfish use metabolic rate suppression to enhance anoxia survival during bouts of anoxia greater than 24 h and that metabolic rate was halved during the final third of a 36-h anoxic period. However, analysis of tissue metabolites in the liver, heart, tongue and skeletal muscle showed that glycogen levels were rapidly depleted over the first 6 h, but then stabilized for the duration of the anoxic exposure. Taken together, the results of the respirometry study and metabolic analysis suggest that anoxia survival in E. stoutii is enhanced by metabolic suppression, but that this suppression may occur earlier in the anoxic period than revealed by EPAOC measurements alone.
To gain a better understanding of the use of metabolic rate suppression as a means for surviving anoxic exposures, cardiovascular function was examined during a 36-h anoxic exposure. Cardiac output and ventral aortic blood pressure were measured for 36 h of anoxia and through full recovery. Anoxic bradycardia that halved heart rate within 3 h, which then remained stable at 5 bpm for 33 h of anoxia. Cardiac output, however, was reduced by only ~33%, suggesting metabolite, hormone and waste transport remain important during anoxia. Furthermore, cardiac power output remained unchanged during anoxia. Thus, cardiac metabolic rate is not suppressed and its routine cardiac ATP demand is met through glycolysis and circulating blood glucose.
4
Anstiss, Julie. "Venous control in a primitive fish Eptatretus cirrhatus." Thesis, University of Canterbury. Biological Sciences, 2005. http://hdl.handle.net/10092/1752.
Full textAbstract:
Only a small amount of the available literature is concerned with venous control in lower vertebrates, such as fish. It has even been suggested that veins in fish are not important factors in active regulation of venous return. Preliminary work carried out for this thesis strongly refuted this assumption, highlighting gaps in the existing literature. As a result of the lack of information pertaining to the physiology of the central venous compartment of the circulation, my objective has been to investigate various aspects of this in the hagfish Eptatretus cirrhatus. Hagfishes, with the lowest arterial blood pressures and highest blood volumes amongst the chordates, are the earliest surviving group to separate off from the chordate lineage. They provide a unique opportunity to investigate likely physiological mechanisms in ancestral chordates. The data presented in this thesis suggest thtat 1) E. cirhatus exhibit some cardiovascular compensation during volume manipulation, however this only occurs with volume loading and not during volume depletion, 2) Veins from E. cirrhatus can respond vasoactively to adrenergic stimulation in vitro and 3) Plasma catecholamines in E. cirrhatus also respond to volume manipulation and provide a potential in vivo mechanism for the control of changes in cardiovascular parameters that were observed during volume loading.
5
Robson, Paul. "Biochemical and molecular studies of the cartilaginous endoskeleton of adult lampreys and hagfish." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0006/NQ41298.pdf.
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6
Depew, Thomas A. "Solid state NMR investigation of protein based biomaterials : Pacific hagfish slime thread and recombinant insect resilin." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/29645.
Full textAbstract:
Nuclear Magnetic Resonance (NMR) was employed to investigate the structure and mechanics
underlying the material properties of two remarkable biomaterials. Hydrated hagfish intermediate
filament (IF) proteins were identified as having a two component nature, consistent with current
structural models. One component is relatively rigid and immobile, the other rubbery, in which
the protein backbone reorients with correlation times on the order of 60 ns. In order to investigate
the role of calcium ions in the formation of hagfish slime, hagfish IFs were exposed to Ca²⁺ ions in
solution. Energy dispersive X-ray spectroscopy revealed that the filaments did bind Ca ions after
exposure. These results were variable and depended largely on the preparation technique.
Recombinant resilins from Drosophila melanogaster and Anopheles gambiae were shown to
have a highly elastic structure. Direct polarization spectra from each protein were analysed and
the majority of the ¹³C peaks assigned successfully. Relaxation measurements report backbone
correlation times on a scale of 2 to 8 ns, providing a molecular scale explanation the outstanding
macroscopic resilience. Tyrosine residues in the resilin protein exhibited longer correlation times
in the aromatic carbons, reflecting decreased mobility near dityrosine crosslinks.
7
Hastey, John Pinkerton. "Effects of acute salinity and temperature change on Pacific hagfish, Eptatretus stoutii; implications for bycatch post release survival." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/37607.
Full textAbstract:
Hagfish captured as bycatch in a commercial fishery may be exposed to a range of elevated temperatures and reduced salinities when brought to the surface but it is not known how this will affect post-release survival. In this study, hagfish were exposed to all combinations of four salinities (33, 28, 23, and 18 g/l) and three temperatures (7, 16 and 25˚C) and sampled following 1, 3 or 6 h exposure to investigate sub-lethal affects on plasma osmolality, [Na⁺], [Cl⁻], [Mg²⁺], and glucose, hematocrit, mean cell haemoglobin concentration , muscle water content, as well as behavioural responses and survival. An additional group of hagfish were sampled after 48 h of recovery (33 g/l at 7˚C) following 3 h exposure to all salinity/temperature combinations to investigate latent effects of exposures.
In general, during exposure to salinity and temperature combinations, plasma osmolality, [Na⁺] and [Cl⁻] decreased as: i) the salinity of exposure was reduced, ii) the duration of exposure was increased or iii) the temperature to which hagfish were exposed was increased. Plasma osmolality did not equilibrate with environmental osmolality within 6 h and appeared to approach an asymptote at 60% equilibration. Behavioural effects were observed during exposure to reduced salinity conditions at all temperatures and included full body contractions, reduced slime production, reduced swimming ability, extended body posture. During exposure to 25˚C, hagfish were often unresponsive to touch. Following 48 h of recovery from 3 h exposure to all salinity/temperature combinations most of the parameters measured were restored, with the exception of plasma glucose levels which remained elevated indicating latent stress. Following recovery from exposure to 23 and 18 g/l at 25˚C, morbidity levels of 14 and 100% were observed. Thus, hagfish captured and immediately brought to the surface and released, without exposure to extreme salinity or temperatures, may not physiologically be negatively affected by a catch and release fishery however, diminished survival should be expected if exposure salinity approaches 18 g/l or water temperature approaches 25˚C. Future research should address the implications of observed behaviours on release survival of hagfish in a natural setting.
8
Taylor, Josi R. "Intestinal HCO3- Secretion in Fish: A Widespread Mechanism with Newly Recognized Physiological Functions." Scholarly Repository, 2009. http://scholarlyrepository.miami.edu/oa_dissertations/263.
Full textAbstract:
Intestinal HCO3- secretion and the excretion of resultant CaCO3 precipitates have become a recognized characteristic of seawater osmoregulation in teleosts; however, this is the first report of this osmoregulatory strategy outside of teleosts and also includes evidence for its use in green turtles, Chelonia mydas. Furthermore, the effects of feeding on intestinal HCO3- secretion were newly investigated in teleosts. Intestinal base secretion via apical Cl-/HCO3- exchange was found to increase following feeding, at a magnitude sufficient to offset the "alkaline tide" commonly associated with digestion. Intestinal HCO3- secretion in marine teleosts draws HCO3- from both endogenous (via hydration of intracellular CO2) and serosal (blood) sources, of which serosal HCO3- was found to contribute a greater proportion to the elevated postprandial intestinal base secretion measured in gulf toadfish, Opsanus beta. The mechanism by which this serosal HCO3- crosses the basolateral membrane for subsequent secretion into the intestinal lumen was confirmed in toadfish to be a basolateral Na+/HCO3- co-transporter, tfNBCe1. Furthermore, the isolated intestinal tissue was found to have a high metabolic rate in both control and postprandial toadfish, with respect to that of the whole animal, and shows a considerable specific dynamic action (SDA) response to feeding. Overall, this dissertation provides evidence for the widespread use of intestinal HCO3- secretion as a strategy of marine osmoregulation across aquatic taxa, and also for its newly recognized involvement in postprandial acid-base balance.
9
Martin, Kyle J. "Genomic characterization of cyclostome Dlx gene family members: Insight into the evolution of the chordate genome and body plan from the organizational and transcriptional regulatory properties of Dlx genes in the petromyzontiformes (lamprey) and the hyperotreti (Hagfish)." Thesis, University of Ottawa (Canada), 2009. http://hdl.handle.net/10393/28234.
Full textAbstract:
Gnathostome novelties include jaws, paired appendages, and true teeth. Dlx genes encode transcription factors indispensable for embryonic development of these novelties. Gnathostomes possess at least 6 Dlx genes organized in 3 bi-gene clusters, a physical arrangement which is proposed to affect their expression though shared enhancer elements. I studied the Dlx genes of Cyclostomes, the evolutionary sister group of Gnathostomes. I identified 4 novel members of the Dlx gene family in hagfish (Eptatretus stoutii), and confirmed the presence of 6 Dlx genes in lamprey ( Petromyzon marinus). I found that Cyclostomes have only 1 gene cluster and several orphan genes. This lack of conserved arrangement is coincident with an absence of conserved Dlx enhancers. Irregardless, some regulatory conservation is still apparent as lamprey non-coding DNA is able to drive dlx specific expression patterns of reporter genes in zebrafish. Therefore Cyclostome and Gnathostome Dlx are both organized and regulated differently. The causes and consequences of these changes in Chordate evolution are discussed.
10
Braun, Christopher B. "The sensory biology of hagfishes (Craniata: Myxinoidea) /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1997. http://wwwlib.umi.com/cr/ucsd/fullcit?p9724888.
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11
Chiu, Kuo-hsun, and 邱國勛. "Proteometabolomics of Hagfish Cardiac and Skeletal Muscles." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/q9ux47.
Full textAbstract:
博士國立中山大學
海洋生物研究所
96
Hagfish are the plesiomorphic sister group of all vertebrates. They are scavengers and many live at depths reaching thousands of meters. In addition, hagfish show the lowest metabolic rate as well as cardiac performance in vertebrates. This dissertation evaluated the biochemical characterizations of hagfish skeletal muscles related to the feeding apparatus and hagfish cardiac muscle associated with cardiac performance and deep-sea effects at the proteomic and metabolomic levels. In Chapter one and two, I found creatine kinase over-expressed in hagfish somatic muscle and deep-sea hagfish cardiac muscle, I suppose that this enzyme was important for utilization of stored phosphocreatine in deep-sea animals’ somatic muscle and cardiac muscle. Over-expressed glycogen phosphorylase in hagfish dental and deep-sea hagfish cardiac muscle supposes these two types of muscles undergoing the anaerobic glycolysis. Compared to teleosts (cobia and tuna), TMAO and urea were higher in hagfish suggest their functions in hagfish cardiac muscle as osmolytes, however, higher TMAO but not urea in deep-sea hagfish, I suggest TMAO functions not only as an osmolyte but also physiological impacts in hagfish cardiac muscle for depth-related adaptations. I also found higher nebulin express in hagfish cardiac muscle and higher tropomyosin express in cobia and tuna cardiac muscles, thus their contractile differentiations were resulted from the protein-protein mechanism. This dissertation provides candidate proteins and metabolits involved in ecophysiological adaptation of hagfish skeletal and cardiac muscles.
12
Fleury, Aharon. "Reproductive biology and ecology of Pacific hagfish (Eptatretus stoutii) and Black hagfish (Eptatretus deani) off the coast of Vancouver Island, BC." Thesis, 2016. http://hdl.handle.net/1828/7529.
Full textAbstract:
Hagfish are one of the more lucrative commercial opportunities in the world with fisheries harvesting them specifically for food and for their skin for leather-based products. In 2013 a three year experimental fishery opened off the west coast of Vancouver Island, British Columbia in order to determine the sustainability of a Pacific hagfish (Eptatretus stoutii) and Black hagfish (Eptatretus deani) fishery. In this study, I examined the reproductive biology of both species including: length-weight relationships, sex ratios, fecundity, and size-at-gonadal development. This study corroborates previous suggestions that Pacific hagfish are juvenile protogynous hermaphrodites while black hagfish are likely to be dioecious with an unknown juvenile stage. Sexual dimorphism appears in both species of hagfish, which is likely the result of inter- and intraspecific morphological differences. For both species fecundity decreases throughout developmental stages, and the average fecundity is very low (27-32 eggs per female). Additionally, in both species females commence gonadal development prior to males. Furthermore, both species exhibited extreme female: male sex ratios across length-classes, however, in opposite directions. The reproductive biology of Pacific and Black hagfish models that of a k-selected species, which is a species that tends to live long and has a slow growth rate, low fecundity, and late maturity. As a result there are a variety of concerns that should be addressed when developing a sustainable hagfish fishery to prevent collapses observed in previous hagfisheries.Graduate
2017-08-23
13
Luo, Hao-Yuan, and 駱皓元. "Parasitism of Anisakid Nematodes and Chondracanthid Copepod in Hagfish." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/38809640177645779305.
Full textAbstract:
碩士國立臺灣大學
生命科學系
103
Hagfishes are the most primitive vertebrates known. They have a cartilaginous skull but no vertebral column. Hagfish is marine benthic scavenger which feed on dead organic matter, including teleosts, cetaceans, marine inverts, etc. Anisakis is transferred by host predation, and their paratenic hosts include crustaceans, cephalopods, and teleost fish. The aim of this study is to investigate the parasitical fauna of hagfish and confirm that hagfish can be infected by Anisakis via host scavenging. Hagfishes were caught from Daxi fishery harbor in northeastern Taiwanese waters from November 2013 to June 2014. A total of 265 samples were examined and four species of the genus Eptatretus, Eptatretus burgeri, E. yangi, E. sheni and E. taiwanae. These four species of hagfishes were infected by Anisakidae nematodes, which parasitized mainly in the gastrointestinal tract wall. Also, anisakid nematodes species were identified by PCR-RFLP. Seven species of nematodes were recorded: Anisakis pegreffii, A. simplex s.s., recombinant genotype of A. pegreffii and A. simplex s.s., A.typica, Anisakis sp., A. brevispiculata and Hysterothylacium amoyense. All Anisakid nematodes are new host records, and two of them (Anisakis sp. and H. amoyense) are new locality records. In addition, a new species of chondracanthid copepod, Acanthochondria eptatreti, was identified and isolated from the pharynx of hagfish, and has been published in 2014. The results proved that anisakid nematodes can transfer by hagfish scavenging and modified Anisakis life cycle. Statistical analysis showed that the prevalences of two kinds of parasites (nematode and copepod) are significant higher in E. burgeri. The intensity of nematodes positively correlated with host size of E. burgeri and E. sheni. The intensity of copepod only has positive correlation with E. burgeri. The accumulation of parasites in larger hosts can be observed in this study.
14
chua, wooi-min, and 蔡偉民. "On The Reproduction of Hagfish, Paramyxine cheni (Myxinidae) from Taiwan." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/08788699098239458198.
Full textAbstract:
碩士國立中山大學
海洋生物研究所
92
Abstract The Taiwanese hagfish Paramyxine cheni (Myxidae) is believed as a primitive species in the Eptatretinae and it distributes on the west south coast of Taiwan. Hagfishes are noteworthy to study from an evolutionary standpoint because they represent the oldest extant clade among the craniates. A better understanding of their reproductive states may thus reveal information for fisheries management. This research presents data on size, weight, GSI (Gonadosomatic Index), HSI ( Hepatosomatic index) and reproductive states for specimens collected at a study site (22°22’43”N, 120°14’92”E) near Tong-kung, Southern Taiwan. Specimens were collected once a months from December 2002 through November 2003 for body weight, body length, gonad weight, liver weight and liver lipid content. GSI, show that the P.cheni had a seasonal reproduction period in April and May. HSI data also show a positive correlation with GSI. The sex ratio among the female, male and sex undeterminated individuals was 0.51：0.20：0.29. The maximum body length was 55.9cm, and smallest body length was 9.5cm. I define the full maturity as appearance of the mushroom-like structure at the tips of the egg. P.cheni matured around 40cm. Gonad developed at 18.5cm body length, when minute eggs observable by naked eye are present. Lipids distribution in liver was significantly different in female before and after the reproduction period; lipid cells were more condense in the former period. Color of liver difference between the male and female P.cheni; male’s liver was more reddish. Therefore, before sex differentiation, I can identify the sex of an individual by the color of its liver.
15
Bernier, Nicholas J. "Adenosine receptor brockade and hypoxia tolerance in rainbow trout and Pacific hagfish." Thesis, 1994. http://hdl.handle.net/2429/5192.
Full textAbstract:
The physiological properties of adenosine may be essential in the control of energy
metabolism for the survival of animals exposed to oxygen shortages. Accordingly, in this
thesis the hypothesis that adenosine modulates the response of rainbow trout and Pacific
hagfish to acute hypoxic exposure was tested.
Three different experimental series were conducted to investigate the possible roles
of adenosine in hypoxia tolerance. Rainbow trout were exposed to either a Pw02 of 30 torr
for 6 h (SERIES I), or to 25 torr for 1 h (SERIES II). Pacific hagfish were exposed either
to a Pw0 of 10 or 30 torr for 1 h (SERIES III). In all three series, the role of adenosine
was assessed by comparing the response of animals treated with non-specific adenosine
receptor blockers to control shams under hypoxic and normoxic conditions. Three different
areas were investigated for adenosine's actions in these experiments: 1) the recruitment of
anaerobic metabolism; 2) the stress response; and 3) the role of erythrocytes for oxygen
capacitance.
Relative to hypoxic sham fish, increases in plasma [lactate] with hypoxic exposure
were greater in the animals injected with the adenosine receptor (AR) blocker theophylline
in all three series. This response to AR blockade was also associated with a more rapid
and pronounced metabolic acidosis in SERIES I & II. In hagfish, plasma [lactate]
increased following exposure to a Pw0 of 10 torr but not 30 torr, and plasma acidosis was
only observed in the animals exposed to a Pw0 of 10 torr and treated with theophylline.
In SERIES II, only the tissues from the hypoxic theophylline treated trout had significant
increases in tissue [lactate] when compared to the normoxic groups. Decreases in creatine
charge were observed in the heart and red muscle, but not white muscle, of theophylline treated fish. The glycogen content of the heart also decreased following theophylline
treatment. The tissue metabolites of hypoxic trout treated with enprofylline, an AR blocker
with very weak affinity, were similar to the hypoxia sham fish, and the increase in plasma
lactate was intermediate to the hypoxic theophylline and sham groups. Both AR blockers
had no measurable effects on normoxic controls. These findings indicate that AR blockade
results in a more rapid and pronounced recruitment of anaerobic metabolism following
acute hypoxic exposure in rainbow trout and Pacific hagfish.
In SERIES I, plasma [Cortisol] increased after 10 min of hypoxic exposure and
remained elevated in the theophylline group. An increase in plasma [Cortisol] was observed
after 30 min of hypoxia but was transient in the hypoxic sham trout. In SERIES II, after
10 min of hypoxic exposure, the plasma [adrenaline] in the theophylline and enprofylline
treatments were respectively 16 and 4 fold higher than in the hypoxic sham treatment. This
difference, although not as pronounced, was maintained after 60 min of acute hypoxia
between the theophylline treatment and the two other hypoxic groups. In hagfish, whereas
plasma [adrenaline] did not change following exposure to a Pw0 of 10 torr in the hypoxic
sham group, the [adrenaline] increased 3.8 fold within 10 min in the theophylline group and
returned to control levels by 60 min. AR blockade with methylxanthines had no effect on
the concentrations of plasma Cortisol and catecholamines in the normoxic animals. These
results indicate that adenosine receptor blockade modulates the primary stress response of
hypoxic rainbow trout and Pacific hagfish.
In rainbow trout, serial blood sampling in SERIES I resulted in a greater [Hb]
decrease in the hypoxic group treated with theophylline than in the hypoxic sham group. In SERIES II, an increased in [Hb] was observed in the hypoxic sham group but not in the
hypoxic groups treated with the AR blockers. In the hagfish experiment, AR blockade had
no effect on the relative decrease in [Hb] in all the treatments. These results indicate that
in hypoxic rainbow trout, AR blockade may prevent splenic release of rbc by abolishing the
stimulatory effects of catecholamines on this tissue. Unlike rainbow trout, Pacific hagfish
may not increase their [Hb] under acute hypoxic conditions.
Results from these experiments show marked differences between rainbow trout and
Pacific hagfish in their response to hypoxia, and in the strategy that each utilizes to resist
such conditions. However, results also indicate that adenosine has an important protective
role in both species, and that the actions of adenosine in fish, as in other vertebrates, may
have a common tendency to reduce energy expenditure, while improving oxygen delivery.
Specifically, adenosine may reduce the extent to which anaerobic metabolism is recruited
upon acute hypoxic exposure, modulate the circulating levels of the primary stress
hormones catecholamines and Cortisol, and play a role in maintaining the oxygen carrying
capacity of the trout by modulating the splenic contribution of rbc.
16
Fudge, Douglas Steven. "The biomechanics of intermediate filament-based materials : insights from hagfish slime threads." Thesis, 2002. http://hdl.handle.net/2429/18204.
Full textAbstract:
Intermediate filaments (IFs) provide mechanical integrity to a wide range of
biomaterials, from soft epithelia to hard keratins such as nail and horn. Although
much is known about the mechanical properties of IF-rich materials such as hair,
the mechanical properties of individual IFs are unknown. In this thesis, I
employed hagfish slime threads, which are composed almost exclusively of
highly aligned IFs, as a model for exploring the mechanics of IFs both in living
cells and keratinized tissues.
Experiments with hydrated slime threads suggest that IFs in cells are extremely
soft, extensible, strong, and tough when compared to actin filaments and
microtubules. These data support the view that the main role of IFs in cells is to
provide mechanical integrity and strength. The data also suggest that IFs are
likely to provide the primary passive mechanism by which cells recover from
large deformations. Structural data suggest that post-yield deformation of IFs
leads to an irreversible α→β transition, which may be used by cells as a
mechanosensory cue.
Tensile tests in air revealed that dehydrated IFs behave similarly to hard akeratins
in water, suggesting that one role of the hard α -keratin matrix is to
maintain IFs in a dehydrated state, even when immersed in water. Recovery tests
suggest that an additional role of the matrix is to permit full recovery from postyield
deformations by both inhibiting β-sheet formation and providing a
restoring force in parallel to the IFs. The dramatic difference in properties
between wet and dry slime threads suggests that hydrated IFs consist of soft and
rigid components arranged in series. These components correspond to the
terminal and coiled coil domains of the IF protein dimers, respectively. This
arrangement of components is the key to understanding the remarkable
mechanical versatility of IFs.
Experiments on hagfish slime revealed aspects of the slime's mechanical
properties, its mechanism of formation, and some behavioral aspects of its
release. Results from these experiments suggest that hagfish slime does not
behave as a fibre-reinforced composite, but as an extremely dilute assemblage of
protein threads and mucins that functions to protect hagfishes from gill-breathing
predators.Science, Faculty of
Zoology, Department of
Graduate
17
Leow, Wai Jia, and 廖譓嘉. "Studies on the characteristics of biochemical compositions and antioxidant activity of hagfish." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/43305168436834459241.
Full textAbstract:
碩士國立臺灣海洋大學
食品科學系
96
Hagfish represents the oldest extant craniates and plesiomorphic sister group for all vertebrates. However, little information has been reported on the biochemical characteristics of hagfish. Therefore, biochemical compositions of four species of hagfish including Eptatretus burgeri, Eptatretus okinoseanus, Paramyxine cheni and Paramyxine sheni were investigated. No significant difference in proximate composition of the muscle between the former three species. However, the lipid content of P. sheni was much higher than the others. The lipid content in liver was the highest, followed by skin, roe, muscle, mucus glands and dental muscle. The contents of protein were found higher in roe, skin and dental muscle. Uridylate (UMP), a nucleotide-related compound (NRC), was rich in the tissues of hagfish, of which the roe was the highest one. Inosinic acid (IMP) was the predominant NRC in the muscle, skin, liver and mucus glands, in which dental muscle had the highest content. The major free amino acids (FAA) of the muscle was proline, followed by valine and leucine. In addition, E. burgeri was also rich in methionine. The content of taurine in hagfish was much lower than those in other species of fish. Dipeptides, carnosine and anserine, were not detected. The total amount of FAA was found the highest in the muscle, and the lowest in the roe. The constituted amino acids (CAA) of peptides showed marked difference among different tissues. Skin had the highest amount of CAA, followed by roe. The contents of soluble protein and amino group were coresponding to the total amounts of CAA and FAA, respectively. Trimethylamine oxide (TMAO) was abundant in the dental muscle, muscle, mucus glands and liver, but not detected in skin and roe. The antioxidation activity of trichloroacetic acid (TCA) extract from mucus glands was stronger than other tissues of E. burgeri, particularly on the inhibition of linoleic acid peroxidation. The chelation of ferrous ion and reducing power of skin and roe were significantly higher than the others. There was no correlation between antioxidation activity and FAA, but the antioxidation activity of skin and roe were related to the content of CAA. The mucus glands TCA extract of E. burgeri was then separated by ultrafiltration, and the fraction with molecular weight of 1∼5 kDa was observed to have the highest antioxidation activity. The elution profile of TCA extract on Sephadex G-25 showed the peptide with molecular weight of approximately 1800 Da possessed the strongest antioxidant activity. Result revealed that small peptides might play an important role on antioxidant activity of mucus glands of hagfish.
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Chien-Hsien, Kuo. "Molecular phylogeny and evolution of hagfish based on mtDNA and lactate dehydrogenase genes." 2000. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0021-2603200719104655.
Full text
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Levy, Nimrod. "Hagfish slime : fine-tuning the mechanical properties of a new high performance fiber." Thesis, 2005. http://hdl.handle.net/2429/16616.
Full textAbstract:
The race to find new high performance materials is at an exciting stage. Science is
in the midst of attempting to investigate any and all materials that are present in
the world with the hope of finding superior, cheaper, environmentally friendly
materials. Nature, it seems has been unknowingly at the race for quite some time,
and is leading it in some areas.
Intermediate filament-based materials promise good mechanical characteristics
with the added benefit of self-assembly. Although much is known about the
mechanical properties of other intermediate filament-rich materials such as wool,
those materials are not purely composed of intermediate filaments and usually
have added complexities in terms of synthetic manufacturing. This thesis focuses
on manipulating and understanding the relationship between structure and
function of essentially pure intermediate filament-based hagfish slime fibers.
Previously described a-helix <-> P-sheet transition in the coiled-coil domains of
hagfish fibers' intermediate filaments subunits was quantified using a novel in
vitro light microscopy technique. This allowed for optimization of draw
processing techniques that lead to improved tensile mechanical properties.
Improvement was achieved via formation of a P-sheet crystal network in the draw
processed fibers.
Dimensional stability was achieved via physical and chemical processing and
resulted in a new candidate environmentally friendly, high-performance fiber.Science, Faculty of
Zoology, Department of
Graduate
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Kuo, Chien-Hsien, and 郭建賢. "Molecular phylogeny and evolution of hagfish based on mtDNA and lactate dehydrogenase genes." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/03269412909281228290.
Full textAbstract:
博士國立臺灣師範大學
生物研究所
89
Abstracts The study included molecular phylogeny of hagfish and evolution of lactate dehydrogenase. The mitochondrial DNA sequences from the large ribosomal RNA gene may be of great value for systematic and phylogenetic studies within families. Partial sequences of the 16S rRNA gene were obtained for comparisons among the following hagfish species, Paramyxine nelsoni, P. sheni, P. taiwanae, P. yangi, P. cheni, Eptatretus burgeri, E. stouii, E. cirrhatus, Myxine glutinosa, M. formosana, M. circifrons, M. sp1 and M. sp2. The boundary of first four Paramyxine species from 16S rRNA sequences is ambiguous; however, they are valid based on our further unpublished isozyme data as well as the gill aperture arrangement pattern. The present molecular data show that the genus Paramyxine is polyphyletic. Eptatretus and Paramyxine form a clade, but their included species can be grouped separately into two different subfamilies, the Myxininae and Eptatretinae. The phylogenetic pattern is not congruent with the number of branchial pouches or branchial apertures proposed by Nelson (1994) and Fernholm (1998), who addressed the evolutionary trend of hagfish as being from polybranchiates to monobranchiates and with all hagfish belonging to a monophyletic group. Furthermore, the larger genetic distance between P. cheni and the other Eptatretinae species suggest that P. cheni could be as a basal taxa in Eptatretinae. A new genus and species of Rubicundus oligoporos collected from the northeastern coast of Taiwan is described here. Rubicundus is distinguished by pink body coloration. Rubicundus oligoporos is a five-gilled species with a three-cusp multicusp on the anterior rows and a two-cusp one on the posterior rows. The putative taxonomic position of Rubicundus is discussed based on mitochondrial 16S rRNA gene fragment sequences. In order to understand the expression of the multiple LDH isozymes in aves, the brain, eye, heart, liver, muscle, and testis were analyzed. Horizontal starch gel electrophoresis was used to examine isozymes of L-lactate dehydrogenase in 4 families and 7 genera of lizards and 33 aves species assigned to 6 orders. Like all other vertebrates, bords possess 2 fundamental LDH loci (LDH-A and LDH-B). A LDH-C product of the third locus was detected in only 8 species of birds and 4 lizards and, for the first time, was reported from the Passeriformes and lizards. The results of this study and those of other previous research suggest that avian LDH-C, reptile LDH-C, and mammalian LDH-C may be orthologous, and may have been derived from ancestor amniote LDH-A. The present study has determined a cDNA sequence of LDH-A from the muscle of hagfish, it contains 1428 nucleotides including a protein-encoding sequences of 1026 nucleotides, the 5’(54 nucleotides) and 3’ (342 nucleotides) untranslated region. The hagfish LDH-A protein that we deduced from the nucleotide sequence is 341 amino acids long. Compared to the other vertebrate LDH, the sequence added 8 amino acids in the low hydrophobicity region at position 220-227. Hagfish LDH unique 9 positions exhibit alternative amino acid those conserved in all vertebrates. None of the alternative amino acids positions makes up the active center. Of the 10 positions that are diagnostic for LDH-A versus LDH-B in the gnathostome vertebrate examined, the hagfish LDH-A sequence resemble LDH-A at four, LDH-B at two, and neither at four. Hagfish LDH, like that of the all vertebrate LDH-As is also missing an amino acid at the penultimate position. The hagfish sequence, with its greater similarity to chordate LDH-A sequence in this region, provides additional evidence that the amino acid was added in the common ancestor of LDH-Bs. Our phylogenetic conclusions that LDH of hagfish muscle is a ancestral LDH-A and the lamprey single locus condition is due to gene loss. Both distance and maximum parsimony analysis strongly reject a relationship of hagfish LDH-A with lamprey LDH.
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曾思堯. "Extraction and biochemical properties of collagen from hagfish (Eptatretus burgeri and E. okinoseanus) skin." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/13778679677589233849.
Full textAbstract:
碩士國立臺灣海洋大學
食品科學系
98
Hagfish is the most primitive non-jaw vertebrate which in Taiwan, mainly in Ilan, Pingtung and Taitung areas for bottom trawl fisheries aquatic. The objectives of this study are to investigate the proximate composition, collagen type, characteristics, amino acid constituents and their antioxidant activities of enzymatic hydrolysates from hagfish (Eptatretus burgeri and E. okinoseanus) skin. The crude protein contents of E. burgeri and E. okinoseanus skin were 26 and 28%, crude fat contents were 8 and 5%, and very low ash contents respectively. The yield of acid soluble collagen (ASC) extracted from E. burgeri and E. okinoseanus skin were 39 and 37%. Two kinds of fish skin ASC were heterotrimers with α-chain, α 1 and α 2, indicating that these skin ASC were Type I collagen. It is no different in two kinds of hagfish. The profile of SDS-PAGE were also similar to that of calf skin collagen Type I. The main amino acids of collagen were Gly, Ala and Pro. Peptide mapping of two kinds of fish skin ASC hydrolysis by trypsin showed similar peptide patterms, Show its amino acid composition similar. The ultraviolet (UV) absorption spectrum of two kinds ASC showed that the distinct absorption was at 220-230 nm. A sharp decrease in solubility was observed in the presence of NaCl, above 3% and 2% (w/v), and denaturation temperatures were 21 and 15oC for E. burgeri and E. okinoseanus, respectively. Two kinds of fish skin collagen without enzyme treatment, their antioxidant activities such as the scavening effect of α,α-diphenyl-β-picrylhydrazyl (DPPH) radical, reducing power and scavenging effect on 2,2'-azinobis-3- ethylbenzothiazoline-6-sulfonic acid (ABTS+) have same capabilities, but the chelation of ferrous ion of ASC form E. burgeri skin was higher than E. okinoseanus. The amino group of ASC form E. burgeri and E. okinoseanus skin which hydrolysate with protamex and alcalase increased during hydrolysis, and ASC of E. okinoseanus skin which hydrolysate with alcalase had highest amino group. The soluble protein of all hydrolysate showed no significant change during hydrolysis. Antioxidant activities of ASC from E. okinoseanus skin with alcalase had better scavenging ability on DPPH radical.
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Wu, Hsiao-Chih, and 吳効直. "Fishing Efficiency in Different Lengths and Weights of Hagfish Pots, and Different Kinds of Baits." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/17274626981778670222.
Full textAbstract:
碩士國立臺灣海洋大學
環境生物與漁業科學學系
93
Abstract The history of hagfishery in the Tungkang area in Taiwan has been more than a decade, which marks a distinguishing local business. Research conducted on the hagfish has been done regarding the biological aspects, including reproduction and physiology etc., but not on the viewpoints of fishing tools and fishing methods. The hagfishery is being developed, in areas along the Pacific coast such as Japan, Korea, America, and Canada for more than forty years. Among all the countries above, Tsushima Island fishermen in Japan employ the longest hagfish pots among those of other countries; the kinds of bait used differ significantly as well. This study is for proper length and weight of hagfish pots, and compare the fishing efficiency with different kinds of baits, then expect to improve the fishing efficiency of hagfish pots. The research in the thesis has conducted a series of experiments in September, 2003 and October, 2004, outside of South China Sea and LiuChiu Yu. In the experiment of how hagfish pot length affects fishing efficiency, the results indicate that the optimum length of hagfish pots is 67cm used by Taiwanese fishermen, and the 80cm-pots used by Tsushima Island Japanese fishermen is valid for being second effective; and the pots over 80cm have been observed to drop apparently in fishing efficiency. As for the 67cm hagfish pots, if attaching lead onto the pots, better fishing results are found to be achieved; however the growth of fishing results only progresses in a limited way. If taking the lead of line hauler into account, the contribution of lead can be in achieved only when a larger line hauler is set up. Four baits were used in baits studies and the results show that Skipjack was the best bait compared with Mackerel,Ribbonfish and Tilapia.
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Fang, Ya-Hsuan, and 方雅玄. "Changes in chemical compositions of hagfish tissues during storage and their antioxidant activities of enzymatic hydrolysates." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/45833373669041206194.
Full textAbstract:
碩士國立臺灣海洋大學
食品科學系
97
Hagfish is the most primitive non-jaw vertebrate which was mainly distributed in Yilan, Pingtong and Taitung areas of Taiwan. The main purposes of this research are to investigate the changes in chemical compositions of hagfish tissues during storage and their antioxidant activities of enzymatic hydrolysates. The pH value of Eptatretus burgeri muscle increased gradually during storage at 25℃. When stored at 4℃, however, the pH value decreased and then increased. For mucus glands, no significant changes in pH value were found. The volatile basic nitrogen (VBN) in the initial stage of the muscle was 5 mg/100 g. After storage at 4℃ for 12 days, VBN exceeded the limited value of 25 mg/100 g, and the value reached 37.87 mg/100 g after storage at 25℃ for 24 hours. The increase of VBN in the muscle was more quickly than that of mucus gland. The dominant ATP-related compounds in the muscle and mucus gland were uridine monophosphate (UMP), inosine-5’-phosphate (IMP), inosine (HxR) and hypoxanthine (Hx). No significant change in the UMP was found during storage. But the decomposition of IMP and HxR resulted in the accumulation of Hx. K value increased during storage, and mucus glands showed more significant changes. The major free amino acid (FAA) of muscle and mucus glands was proline. The total FAA amount increased in the beginning and decreased in the later stage of storage at 4℃and 25℃. The scavenging effect of DPPH radical significantly increased after storage at 4℃ for 9 days and 12 days, but no significant change was found at 25℃. Reducing power showed no marked difference between tissues during storage. The chelation of ferrous ion of the muscle decreased gradually during storage. For mucus glands it increased in the beginning and decreased in the later stage of storage at 4℃, but increased at 25℃. The soluble protein of Eptatretus okinoseanus muscle and mucus glands hydeolysates with Alcalase and Protamex increased during hydrolysis, but fish skin hydrolysate decreased gradually. The amino group of three tissue hydrolysates increased gradually during hydrolysis, of which fish skin hydrolysate had the highest value. The predominant FAA in Eptatretus okinoseanus muscle, skin and mucus glands was proline, accounting for 15% to 19% of the total FAA. The FAA of Protamex skin hydrolysate decreased after 15 hour hydrolysis, but other tissue hydrolysates increased gradually during hydrolysis. The amino group of Protamex hydrolysate had a higher amount than Alcalase. The total constituted amino acid (CAA) in fish skin hydrolysate was higher than that of other hydrolysates. The production of peptides with Protamex hydrolysis on the muscle had the higher efficiency than Alcalase. The scavenging effect of DPPH radical of all hydrolysates increased significantly with the hydrolysis time, and the muscle hydrolysate had the highest ability. All tissue hydrolysates possessed the ability to inhibit linoleic acid autoxidation. The reducing power of all hydrolysates showed no significant change during hydrolysis. In addition, the ferrous ion chelation of the hydrolysates decreased with the increase of time.
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Stadler, Peter F., Claudia Fried, Sonja J. Prohaska, Wendy J. Bailey, Bernhard Y. Misof, Frank H. Ruddle, and Günter P. Wagner. "Evidence for independent Hox gene duplications in the hagfish lineage: a PCR-based gene inventory of Eptatretus stoutii." 2004. https://ul.qucosa.de/id/qucosa%3A31923.
Full textAbstract:
Hox genes code for transcription factors that play a major role in the development of all animal phyla. In invertebrates these genes usually occur as tightly linked cluster, with a few exceptions where the clusters have been dissolved. Only in vertebrates multiple clusters have been demonstrated which arose by duplication from a single ancestral cluster. This history of Hox cluster duplications, in particular during the early elaboration of the vertebrate body plan, is still poorly understood. In this paper we report the results of a PCR survey on genomic DNA of the pacific hagfish Eptatretus stoutii. Hagfishes are one of two clades of recent jawless fishes that are an offshoot of the early radiation of jawless vertebrates. Our data provide evidence for at least 33 distinct Hox genes in the hagfish genome, which is most compatible with the hypothesis of multiple Hox clusters. The largest number, seven, of distinct homeobox fragments could be assigned to paralog group 9, which could imply that the hagfish has more than four clusters. Quartet mapping reveals that within each paralog group the hagfish sequences are statistically more closely related to gnathostome Hox genes than with either amphioxus or lamprey genes. These results support two assumptions about the history of Hox genes: (1) The association of hagfish homeobox sequences with gnathostome sequences suggests that at least one Hox cluster duplication event happened in the stem of vertebrates, i.e., prior to the most recent common ancestor of jawed and jawless vertebrates. (2) The high number of paralog group 9 sequences in hagfish and the phylogenetic position of hagfish suggests that the hagfish lineage underwent additional independent Hox cluster/-gene duplication events.
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Lee, Yi-Hsin, and 李懿欣. "A histological study on the inner ear of the hagfish Paramyxine nelson with special reference to the statoconia morphology." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/58778716395303608702.
Full textAbstract:
碩士國立中山大學
海洋生物研究所
90
The agnathan hagfish is the plesiomorphic sister group of vertebrates. It is eel-liked, cartilaginous, and has only one semicircular canal. As hagfish have no hard structures that age determination remains unsuccessful. In the present work, we examined the statoconia in the inner ear of the hagfish Paramyxine nelsoni intense to explore it as a useful index in hagfish’s age determination. P. nelsoni is quite abundant at some localities in the southwestern coast of Taiwan. Due to its smaller size, P. nelsoni is not a commercial species in this area. Little information on its populations is available in the literature. Consequently P. nelsoni is a potential model species for fisheries study of hagfish. The statoconia of the P. nelsoni were deciphered from 49 specimens with body length ranging from 10.2cm to 29.5cm. The semicircular canals were examined using scanning electron microscope. Histological sections for the semicircular canals were also made for observation of cytological characters. The masses of statoconia were located on the surface of the macular epithelium. The epithelium of macula was psudostratified columnar type, which was composed of hair cells and supporting cells. Diameters of the statoconia were ranged from 1 µm to 26 µm (3.41± 0.29 µm). Most of them were distributed in a narrow range from 4 µm to 8 µm. Both small (<4μm) and large (>8μm) statoconia were observed in all size of Paramyxine nelsoni. The diameter of statoconia was not correlated with body length. Although the numbers of statoconia were increased with body length, it was not separate clearly between each body size. The shape index (short diameter/long diameter) was decreased when the long diameters of statoconia were larger than 6 µm. This result suggests that statoconia are produced to accumulate from round to ellipse throughout hagfish’s life span. In conclusion, both of the diameters and numbers of statoconia may not be appropriate index in age determination of hagfish.
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Herr, Julia Emily. "Mechanisms of Rupture of Mucin Vesicles from the Slime of Pacific Hagfish (Eptatretus stoutii): Roles of Inorganic Ions and Aquaporin Water Channels." Thesis, 2012. http://hdl.handle.net/10214/3687.
Full textAbstract:
Pacific hagfish (Eptatretus stoutii) slime mucin vesicles are released by holocrine secretion with membranes that remain intact until the vesicle contacts seawater and ruptures. This thesis is an investigation of the mechanisms that drive mucin vesicle rupture for mucin release. Using isolated mucin vesicles collected from the slime glands of the hagfish, I tested the effects of a variety of solutions and drugs on vesicle rupture. I found that there are two categories of mucin vesicle that differ in their sensitivity to calcium ions, and that calcium-dependent vesicle rupture was inhibited with anion channel inhibitors. I also found that vesicle swelling rate was reduced by the aquaporin inhibitor mercuric chloride. Together, these data suggest that mucin vesicle rupture is partially dependent on the movement of chloride ions from seawater through calcium-activated anion channels and the rapid influx of water through aquaporin-like proteins in the vesicle membrane.NSERC Discovery Grant, NSERC CGSM scholarship, Canada Foundation for Innovation, Ontario Ministry of Research and Innovation