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Michelle K Biederman, Megan M Nelson, Kathryn C Asalone, Alyssa L Pedersen, Colin J Saldanha, John R Bracht
Developmentally programmed genome rearrangements are rare in vertebrates, but have been reported in scattered lineages including the bandicoot, hagfish, lamprey, and zebra finch (Taeniopygia guttata) [1]. In the finch, a well-studied animal model for neuroendocrinology and vocal learning [2], one such programmed genome rearrangement involves a germline-restricted chromosome, or GRC, which is found in germlines of both sexes but eliminated from mature sperm [3, 4]. Transmitted only through the oocyte, it displays uniparental female-driven inheritance, and early in embryonic development is apparently eliminated from all somatic tissue in both sexes [3, 4]...
April 28, 2018: Current Biology: CB
John B Hume, Michael Wagner
Alarm signals released after predator attack function as reliable public information revealing areas of high risk. The utility of this information can extend beyond species boundaries, benefiting heterospecifics capable of recognizing and responding appropriately to the signal. Nonmutually exclusive hypotheses explaining the acquisition of heterospecific reactivity to cues suggest it could be conserved phylogenetically following its evolution in a common ancestor (a species-level effect) and/or learned during periods of shared risk (a population-level effect; e...
April 2018: Ecology and Evolution
Jung Seok Lee, Jaesung Kim, Se Pyeong Im, Si Won Kim, Jassy Mary S Lazarte, Jae Wook Jung, Tae Won Gong, Young Rim Kim, Jeong Ho Lee, Hyoung Jun Kim, Tae Sung Jung
Variable lymphocyte receptors B (VLRBs) are non-immunoglobulin components of the humoral immune system in jawless vertebrates including hagfish (Eptatretus burgeri) and lamprey (Petromyzon marinus). Hagfish VLRBs consist of leucine rich repeat (LRR) modules with a superhydrophobic C-terminal tail, the latter of which leads to extremely low expression levels in recombinant protein technology. Here, we present an artificially oligomerized VLRB (arVLRB) that conjugates via the C4bp oligomerization domain derived from human C4b-binding protein (hC4bp) rather than the superhydrophobic tail...
April 18, 2018: Molecular Immunology
Manuel A Pombal, Manuel Megías
Lampreys, together with hagfishes, are the only extant representatives of the oldest branch of vertebrates, the agnathans, which are the sister group of gnathostomes; therefore, studies on these animals are of great evolutionary significance. Lampreys exhibit a particular life cycle with remarkable changes in their behavior, concomitant, in part, with important modifications in the head and its musculature, which might influence the development of the cranial nerves. In this context, some cranial nerves such as the optic nerve and the ocular motor nerves, which develop slowly during an extremely long larval period lasting more than five years, have been more thoroughly investigated; however, much less experimental information is available about others, such as the facial or the hypoglossal nerves...
April 16, 2018: Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology
Juan Pascual-Anaya, Iori Sato, Fumiaki Sugahara, Shinnosuke Higuchi, Jordi Paps, Yandong Ren, Wataru Takagi, Adrián Ruiz-Villalba, Kinya G Ota, Wen Wang, Shigeru Kuratani
Hox genes exert fundamental roles for proper regional specification along the main rostro-caudal axis of animal embryos. They are generally expressed in restricted spatial domains according to their position in the cluster (spatial colinearity)-a feature that is conserved across bilaterians. In jawed vertebrates (gnathostomes), the position in the cluster also determines the onset of expression of Hox genes (a feature known as whole-cluster temporal colinearity (WTC)), while in invertebrates this phenomenon is displayed as a subcluster-level temporal colinearity...
April 2, 2018: Nature Ecology & Evolution
Robin J Gunn, Brantley R Herrin, Sharmistha Acharya, Max D Cooper, Ian A Wilson
Variable lymphocyte receptors (VLRs) are unconventional adaptive immune receptors relatively recently discovered in the phylogenetically ancient jawless vertebrates, lamprey and hagfish. VLRs bind antigens using a leucine-rich repeat (LRR) fold and are the only known adaptive immune receptors that do not utilize an immunoglobulin (Ig) fold for antigen recognition. While Ig-antibodies have been studied extensively, there are comparatively few studies on antigen recognition by VLRs, particularly for protein antigens...
March 26, 2018: Journal of Molecular Biology
Koh Onimaru, Shigehiro Kuraku
Inferring the phenotype of the last common ancestor of living vertebrates is a challenging problem because of several unresolvable factors. They include the lack of reliable out-groups of living vertebrates, poor information about less fossilizable organs and specialized traits of phylogenetically important species, such as lampreys and hagfishes (e.g. secondary loss of vertebrae in adult hagfishes). These factors undermine the reliability of ancestral reconstruction by traditional character mapping approaches based on maximum parsimony...
March 16, 2018: Briefings in Functional Genomics
Sarah Schorno, Todd E Gillis, Douglas S Fudge
Hagfishes are known for their unique defensive slime, which they use to ward off gill-breathing predators. Although much is known about the slime cells (gland thread cells and gland mucous cells), little is known about how long slime gland refilling takes, or how slime composition changes with refilling or repeated stimulation of the same gland. Slime glands can be individually electrostimulated to release slime, and this technique was used to measure slime gland refilling times for Atlantic and Pacific hagfish...
April 6, 2018: Journal of Experimental Biology
Noritaka Adachi, Juan Pascual-Anaya, Tamami Hirai, Shinnosuke Higuchi, Shigeru Kuratani
Background: The extant vertebrates include cyclostomes (lamprey and hagfish) and crown gnathostomes (jawed vertebrates), but there are various anatomical disparities between these two groups. Conspicuous in the gnathostomes is the neck, which occupies the interfacial domain between the head and trunk, including the occipital part of the cranium, the shoulder girdle, and the cucullaris and hypobranchial muscles (HBMs). Of these, HBMs originate from occipital somites to form the ventral pharyngeal and neck musculature in gnathostomes...
2018: Zoological Letters
Alan M Friedlander, Enric Ballesteros, Tom W Bell, Jonatha Giddens, Brad Henning, Mathias Hüne, Alex Muñoz, Pelayo Salinas-de-León, Enric Sala
The vast and complex coast of the Magellan Region of extreme southern Chile possesses a diversity of habitats including fjords, deep channels, and extensive kelp forests, with a unique mix of temperate and sub-Antarctic species. The Cape Horn and Diego Ramírez archipelagos are the most southerly locations in the Americas, with the southernmost kelp forests, and some of the least explored places on earth. The giant kelp Macrocystis pyrifera plays a key role in structuring the ecological communities of the entire region, with the large brown seaweed Lessonia spp...
2018: PloS One
Alexander M Clifford, Alyssa M Weinrauch, Greg G Goss
Hagfish are capable of tolerating extreme hypercapnia (> 30 Torr) by mounting substantial plasma [HCO3 - ] (hypercarbia) to compensate for CO2 -mediated acidosis. The goal of this study was to characterize the mechanistic hypercarbia-recovery strategies in the highly CO2 tolerant hagfish. We exposed hagfish to hypercapnia (30 Torr) for 48 h and allowed a 24 h recovery period in normocapnic seawater. Within 8 h of the recovery period, the compensatory plasma [HCO3 - ] load (~ 70 mmol L-1 ) was rapidly offloaded...
December 30, 2017: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
Sarah Boggett, Jean-Luc Stiles, Adam P Summers, Douglas S Fudge
Hagfishes defend themselves from fish predators by releasing large volumes of gill-clogging slime when they are attacked. Slime release is not anticipatory, but is only released after an attack has been initiated, raising the question of how hagfishes survive the initial attack, especially from biting predators such as sharks. We tested two hypotheses that could explain how hagfishes avoid damage from shark bites: puncture-resistant skin, and a loose and flaccid body design that makes it difficult for teeth to penetrate body musculature and viscera...
December 2017: Journal of the Royal Society, Interface
Alyssa M Weinrauch, Alexander M Clifford, Greg G Goss
This study examined the mechanisms of glucose acquisition in the hindgut of Pacific hagfish (Eptatretus stoutii) using in vitro gut sac techniques. The intestine was determined to have the capacity to digest maltose into glucose along the entirety of the tract, including the foregut. Glucose uptake was biphasic and consisted of a high-affinity, low-capacity concentration-dependent component conforming to Michaelis-Menten kinetics (Km 0.37mM, Jmax 8.48nmol/cm2 /h) as well as a diffusive component. There was no observed difference in glucose flux rate along the length of the intestine, similar to other nutrients investigated in the hagfish intestine...
February 2018: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
Stacia A Sower
The hypothalamic-pituitary (HP) system, which is specific to vertebrates, is considered to be an evolutionary innovation that emerged prior to or during the differentiation of the ancestral jawless vertebrates (agnathans) leading to the neuroendocrine control of many complex functions. Along with hagfish, lampreys represent the oldest lineage of vertebrates, agnathans (jawless fish). This review will highlight our discoveries of the major components of the lamprey HP axis. Generally, gnathostomes (jawed vertebrates) have one or two hypothalamic gonadotropin-releasing hormones (GnRH) while lampreys have three hypothalamic GnRHs...
October 27, 2017: General and Comparative Endocrinology
Marianne A Grant, David L Beeler, Katherine C Spokes, Junmei Chen, Harita Dharaneeswaran, Tracey E Sciuto, Ann M Dvorak, Gianluca Interlandi, José A Lopez, William C Aird
Hemostasis in vertebrates involves both a cellular and a protein component. Previous studies in jawless vertebrates (cyclostomes) suggest that the protein response, which involves thrombin-catalyzed conversion of a soluble plasma protein, fibrinogen, into a polymeric fibrin clot, is conserved in all vertebrates. However, similar data are lacking for the cellular response, which in gnathostomes is regulated by von Willebrand factor (VWF), a glycoprotein that mediates the adhesion of platelets to the subendothelial matrix of injured blood vessels...
December 7, 2017: Blood
Jing Fu, Paul A Guerette, Andrea Pavesi, Nils Horbelt, Chwee Teck Lim, Matthew J Harrington, Ali Miserez
Stiff fibers are used as reinforcing phases in a wide range of high-performance composite materials. Silk is one of the most widely studied bio-fibers, but alternative materials with specific advantages are also being explored. Among these, native hagfish (Eptatretus stoutii) slime thread is an attractive protein-based polymer. These threads consist of coiled-coil intermediate filaments (IFs) as nano-scale building blocks, which can be transformed into extended β-sheet-containing chains upon draw-processing, resulting in fibers with impressive mechanical performance...
September 14, 2017: Nanoscale
Zerina Johanson, Moya Smith, Sophie Sanchez, Tim Senden, Kate Trinajstic, Cathrin Pfaff
Palaeospondylus gunni Traquair, 1890 is an enigmatic Devonian vertebrate whose taxonomic affinities have been debated since it was first described. Most recently, Palaeospondylus has been identified as a stem-group hagfish (Myxinoidea). However, one character questioning this assignment is the presence of three semicircular canals in the otic region of the cartilaginous skull, a feature of jawed vertebrates. Additionally, new tomographic data reveal that the following characters of crown-group gnathostomes (chondrichthyans + osteichthyans) are present in Palaeospondylus: a longer telencephalic region of the braincase, separation of otic and occipital regions by the otico-occipital fissure, and vertebral centra...
July 2017: Royal Society Open Science
Michio Hori, Mifuyu Nakajima, Hiroki Hata, Masaki Yasugi, Satoshi Takahashi, Masanori Nakae, Kosaku Yamaoka, Masanori Kohda, Jyun-Ichi Kitamura, Masayoshi Maehata, Hirokazu Tanaka, Norihiro Okada, Yuichi Takeuchi
Laterality has been studied in several vertebrates, mainly in terms of brain lateralization and behavioral laterality, but morphological asymmetry has not been extensively investigated. Asymmetry in fishes was first described in scale-eating cichlids from Lake Tanganyika, in the form of bilateral dimorphism in which some individuals, when opening their mouths, twist them to the right and others to the left. This asymmetry has a genetic basis, and is correlated with lateralized attack behaviors. This has subsequently been found in fishes from numerous taxa with various feeding habits...
August 2017: Zoological Science
Alyssa M Weinrauch, Alexander M Clifford, Greg G Goss
Hagfishes are unique to the vertebrate lineage in that they acquire dissolved nutrients across multiple epithelia including the intestine, gill, and skin. This feat has been attributed to their immersive feeding behavior that likely simultaneously provides benefits (nutrient rich) and potentially adverse (hypercapnia, hypoxia, high environmental ammonia) physiological effects. Examinations have been conducted of the ex vivo transport capabilities of specific nutrients as well as in vivo effects of the hypothesized feeding environments, yet the physiological effects of feeding itself have never been elucidated...
January 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
Mikihiro Kase, Takayuki Shimizu, Keita Kamino, Kazuo Umetsu, Hideki Sugiyama, Takashi Kitano
The brown hagfish (Eptatretus atami) is one of several known hagfish species occurring in Japanese coastal waters. To date, there has been no research studying genetic polymorphisms in the species. In the present study, we analyzed differences in nucleotide sequences between two populations: one from Suruga Bay on the Pacific coast of Honshu, Japan, and the other from the Sea of Japan, off Akita on the northwest coast of Honshu. We sequenced part of the cytochrome oxidase subunit 1 gene (COX1) from the mitochondrial genome, and three G protein-coupled receptor genes from the nuclear genome...
February 10, 2018: Genes & Genetic Systems
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