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Abigail Elizur - One of the best experts on this subject based on the ideXlab platform.
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Primordial germ cell migration in the yellowtail kingfish (Seriola lalandi) and identification of stromal cell-derived factor 1
General and comparative endocrinology, 2015Co-Authors: J.a. Fernández, Erin J. Bubner, Yutaka Takeuchi, Goro Yoshizaki, Tianfang Wang, Scott F. Cummins, Abigail ElizurAbstract:Primordial germ cells (PGCs) are progenitors of the germ cell lineage, giving rise to either spermatogonia or oogonia after the completion of gonadal differentiation. Currently, there is little information on the mechanism of PGCs migration leading to the formation of the primordial gonad in Perciform fish. Yellowtail kingfish (Seriola lalandi) (YTK) (order Perciforms) inhabit tropical and temperate waters in the southern hemisphere. Fundamental details into the molecular basis of larval development in this species can be easily studied in Australia, as they are commercially cultured and readily available. In this study, histological analysis of YTK larvae revealed critical time points for the migration of PGCs to the genital ridge, resulting in the subsequent development of the primordial gonad. In YTK larvae at 3, 5, 7 and 10 days post hatch (DPH), PGCs were not yet enclosed by somatic cells, indicating the primordial gonad had not yet started to form. While at 15, 18 and 20 DPH PGCs had already settled at the genital ridge and started to become enclosed by somatic cells indicating the primordial gonad had started to develop. A higher number of PGCs were observed in the larvae at 15 and 18 DPH indicating PGCs proliferation, which corresponds with them becoming enclosed by the somatic cells. Directional migration of PGCs toward the genital ridge is a critical event in the subsequent development of a gonad. In zebrafish, mouse and chicken, stromal-cell derived factor (SDF1) signalling is one of the key molecules for PGC migration. We subsequently isolated from YTK the SDF1 (Slal-SDF1) gene, which encodes for a 98-residue precursor protein with a signal peptide at the N-terminus. There is spatial conservation between fish species of four cysteine residues at positions C9, C11, C34 and C49, expected to form disulphide bonds and stabilize the SDF structure. In YTK, Slal-SDF1 gene expression analyses shows that this gene is expressed in larvae from 1 to 22 DPH and demonstrates distinct spatial localisation in the larvae at 7 DPH. These results provide a platform for further studies into the molecular machinery of PGC migration in yellowtail kingfish, as well as other Perciform fish species.
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the kiss2 receptor kiss2r gene in southern bluefin tuna thunnus maccoyii and in yellowtail kingfish seriola lalandi functional analysis and isolation of transcript variants
Molecular and Cellular Endocrinology, 2012Co-Authors: Josephine Nocillado, Jakob Biran, Y Y Lee, Berta Levavisivan, Alejandro S Mechaly, Yonathan Zohar, Abigail ElizurAbstract:The kisspeptin system plays an essential role in reproductive function in vertebrates, particularly in the onset of puberty. We investigated the kisspeptin system in two Perciform teleosts, the Southern Bluefin Tuna (SBT; Thunnus maccoyii), and the Yellowtail Kingfish (YTK; Seriola lalandi), by characterising their kisspeptin 2 receptor (Kiss2r) genes. In addition to the full length Kiss2r cDNA sequences, we have isolated from SBT and YTK a transcript variant that retained an intron. We have further obtained three ytkKiss2r transcript variants that contained deletions. In vitro functional analysis of the full length SBT and YTK Kiss2r showed higher response to Kiss2-10 than to Kiss1-10, with stronger transduction via PKC than PKA. The full length ytkKiss2r and two deletion variants were differentially expressed in the brain of male, but not in female, juvenile YTK treated with increasing doses of Kiss2-10 peptide. In the gonads, the expression level of the ytkKiss2r transcripts did not vary significantly either in the male or female fish. This is the first time that transcript variants of the Kiss2r gene that contain deletions and show responsiveness to treatments with kisspeptin have been reported in any teleost.
Roi Holzman - One of the best experts on this subject based on the ideXlab platform.
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Co-evolution of the premaxilla and jaw protrusion in cichlid fishes (Heroine
2016Co-Authors: Darrin C. Hulsey, Phillip R. Hollingsworth, Roi HolzmanAbstract:The ability of Perciform fishes to protrude their jaw has likely been critical to the trophic diversification of this group, which includes approximately 20 % of all vertebrates. The length of the ascending process of the premaxilla is thought to influence the maximum extent that cichlids and other Perciforms protrude their oral jaw. Using a combination of morphometrics, kinematics, and new phylogenetic hypotheses for 20 Heroine cichlid species, we tested the evolutionary relationship between the length of the premaxillary ascending process and maximum jaw protrusion. In this clade, the length of the ascending process of the premaxilla ranged from 11.6–32.7 % with respect to standard length whereas maximum jaw protrusion ranged from 3.5–23.4 % with respect to standard length. The evolutionary relationships among the Heroine cichlids obtained from the genetic partitions cytochrome b, S7, and RAG1 showed limited concordance. However, correlations between the length of the ascending process and maximum jaw protrusion were highly significant when examined as independent contrasts using all three topologies. Evolutionary change in the length of the ascending process of the premaxilla is likely critical for determining the amount of jaw protrusion in Perciform groups such as cichlid fishes. © 2010 The Linnean Societ
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Co-evolution of the premaxilla and jaw protrusion in cichlid fishes (Heroine: Cichlidae)
Biological Journal of the Linnean Society, 2010Co-Authors: C. Darrin Hulsey, Phillip R. Hollingsworth, Roi HolzmanAbstract:The ability of Perciform fishes to protrude their jaw has likely been critical to the trophic diversification of this group, which includes approximately 20% of all vertebrates. The length of the ascending process of the premaxilla is thought to influence the maximum extent that cichlids and other Perciforms protrude their oral jaw. Using a combination of morphometrics, kinematics, and new phylogenetic hypotheses for 20 Heroine cichlid species, we tested the evolutionary relationship between the length of the premaxillary ascending process and maximum jaw protrusion. In this clade, the length of the ascending process of the premaxilla ranged from 11.6–32.7% with respect to standard length whereas maximum jaw protrusion ranged from 3.5–23.4% with respect to standard length. The evolutionary relationships among the Heroine cichlids obtained from the genetic partitions cytochrome b, S7, and RAG1 showed limited concordance. However, correlations between the length of the ascending process and maximum jaw protrusion were highly significant when examined as independent contrasts using all three topologies. Evolutionary change in the length of the ascending process of the premaxilla is likely critical for determining the amount of jaw protrusion in Perciform groups such as cichlid fishes. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 619–629.
Phillip R. Hollingsworth - One of the best experts on this subject based on the ideXlab platform.
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DOI:10.1093/sysbio/syr052 Advance Access publication on July 20, 2011 Phylogeny and Temporal Diversification of Darters (Percidae: Etheostomatinae)
2016Co-Authors: Thomas J Near, Phillip R. Hollingsworth, Christen M. Bossu, Gideon S. Bradburd, Rose L. Carlson, Richard C. Harrington, Benjamin P. Keck, A. EtnierAbstract:Abstract.—Discussions aimed at resolution of the Tree of Life are most often focused on the interrelationships of major organismal lineages. In this study, we focus on the resolution of some of the most apical branches in the Tree of Life through exploration of the phylogenetic relationships of darters, a species-rich clade of North American freshwater fishes. With a near-complete taxon sampling of close to 250 species, we aim to investigate strategies for efficient multilocus data sampling and the estimation of divergence times using relaxed-clock methods when a clade lacks a fossil record. Our phylogenetic data set comprises a single mitochondrial DNA (mtDNA) gene and two nuclear genes sampled from 245 of the 248 darter species. This dense sampling allows us to determine if a modest amount of nuclear DNA sequence data can resolve rela-tionships among closely related animal species. Darters lack a fossil record to provide age calibration priors in relaxed-clock analyses. Therefore, we use a near-complete species–sampled phylogeny of the Perciform clade Centrarchidae, which ha
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DOI:10.1093/sysbio/syr052 Phylogeny and Temporal Diversification of Darters (Percidae: Etheostomatinae)
2016Co-Authors: Thomas J Near, Phillip R. Hollingsworth, Christen M. Bossu, Gideon S. Bradburd, Rose L. Carlson, Richard C. Harrington, Benjamin P. Keck, A. EtnierAbstract:Abstract.—Discussions aimed at resolution of the Tree of Life are most often focused on the interrelationships of major organismal lineages. In this study, we focus on the resolution of some of the most apical branches in the Tree of Life through exploration of the phylogenetic relationships of darters, a species-rich clade of North American freshwater fishes. With a near-complete taxon sampling of close to 250 species, we aim to investigate strategies for efficient multilocus data sampling and the estimation of divergence times using relaxed-clock methods when a clade lacks a fossil record. Our phylogenetic data set comprises a single mitochondrial DNA (mtDNA) gene and two nuclear genes sampled from 245 of the 248 darter species. This dense sampling allows us to determine if a modest amount of nuclear DNA sequence data can resolve rela-tionships among closely related animal species. Darters lack a fossil record to provide age calibration priors in relaxed-clock analyses. Therefore, we use a near-complete species–sampled phylogeny of the Perciform clade Centrarchidae, which has a rich fossil record, to assess two distinct strategies of external calibration in relaxed-clock divergence time estimates o
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Co-evolution of the premaxilla and jaw protrusion in cichlid fishes (Heroine
2016Co-Authors: Darrin C. Hulsey, Phillip R. Hollingsworth, Roi HolzmanAbstract:The ability of Perciform fishes to protrude their jaw has likely been critical to the trophic diversification of this group, which includes approximately 20 % of all vertebrates. The length of the ascending process of the premaxilla is thought to influence the maximum extent that cichlids and other Perciforms protrude their oral jaw. Using a combination of morphometrics, kinematics, and new phylogenetic hypotheses for 20 Heroine cichlid species, we tested the evolutionary relationship between the length of the premaxillary ascending process and maximum jaw protrusion. In this clade, the length of the ascending process of the premaxilla ranged from 11.6–32.7 % with respect to standard length whereas maximum jaw protrusion ranged from 3.5–23.4 % with respect to standard length. The evolutionary relationships among the Heroine cichlids obtained from the genetic partitions cytochrome b, S7, and RAG1 showed limited concordance. However, correlations between the length of the ascending process and maximum jaw protrusion were highly significant when examined as independent contrasts using all three topologies. Evolutionary change in the length of the ascending process of the premaxilla is likely critical for determining the amount of jaw protrusion in Perciform groups such as cichlid fishes. © 2010 The Linnean Societ
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Co-evolution of the premaxilla and jaw protrusion in cichlid fishes (Heroine: Cichlidae)
Biological Journal of the Linnean Society, 2010Co-Authors: C. Darrin Hulsey, Phillip R. Hollingsworth, Roi HolzmanAbstract:The ability of Perciform fishes to protrude their jaw has likely been critical to the trophic diversification of this group, which includes approximately 20% of all vertebrates. The length of the ascending process of the premaxilla is thought to influence the maximum extent that cichlids and other Perciforms protrude their oral jaw. Using a combination of morphometrics, kinematics, and new phylogenetic hypotheses for 20 Heroine cichlid species, we tested the evolutionary relationship between the length of the premaxillary ascending process and maximum jaw protrusion. In this clade, the length of the ascending process of the premaxilla ranged from 11.6–32.7% with respect to standard length whereas maximum jaw protrusion ranged from 3.5–23.4% with respect to standard length. The evolutionary relationships among the Heroine cichlids obtained from the genetic partitions cytochrome b, S7, and RAG1 showed limited concordance. However, correlations between the length of the ascending process and maximum jaw protrusion were highly significant when examined as independent contrasts using all three topologies. Evolutionary change in the length of the ascending process of the premaxilla is likely critical for determining the amount of jaw protrusion in Perciform groups such as cichlid fishes. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 619–629.
Christopher J. Secombes - One of the best experts on this subject based on the ideXlab platform.
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The discovery and comparative expression analysis of three distinct type I interferons in the Perciform fish, meagre (Argyrosomus regius).
Developmental and comparative immunology, 2018Co-Authors: Douglas J. Milne, Cindy Campoverde, Karl B. Andree, Xinhua Chen, J. Zou, Christopher J. SecombesAbstract:Type I interferons (IFN) play an important role in anti-viral responses. In teleost fish multiple genes exist, that are classified by group/subgroup. That multiple subgroups are present in Acanthopterygian fish has only become apparent recently, and 3 subgroups are now known to be expressed, including a new subgroup termed IFNh. However, the potential to express multiple IFN subgroups and their interplay is not well defined. Hence this study aims to clarify the situation and undertook the first in-depth analysis into the nature and expression of IFNc, IFNd and IFNh in the Perciform fish, meagre. Constitutive expression was analysed initially during larval development and in adult tissues (gills, mid-gut, head kidney, spleen). During early ontogeny IFNc was the highest expressed IFN, and this was also the case in adult tissues with the exception of gills where IFNd was highest. However, comparison between tissues for individual isoforms showed that spleen had high transcript levels of all three IFNs, IFNd/IFNh were also highly expressed in gills. The expression of each sub-group was increased significantly in the four tissues following injection of poly I:C, however, this increase was only seen in the mid-gut for IFNh. Following in vitro stimulation with poly I:C again all three isoforms were upregulated, although with differences in kinetics and the cell source used. For example, early induction was seen for IFNc/IFNh in gill cells, IFNd/IFNh in splenocytes and all three isoforms in head kidney cells. Induction was sustained in splenocytes and head kidney cells, but in gut cells only a late induction was seen. These results demonstrate a complex pattern of regulation between the different IFN isoforms present in meagre and highlights potential sub-functionalisation of these IFN subgroups during Perciform anti-viral responses.
Potts - One of the best experts on this subject based on the ideXlab platform.
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Implantation, orientation and validation of a commercially produced heart-rate logger for use in a Perciform teleost fish
Conservation physiology, 2020Co-Authors: Cuen Muller, Amber-robyn Childs, Murray I. Duncan, Michael R. Skeeles, Nicola C. James, Kerry-ann Van Der Walt, Ac Winkler, PottsAbstract:Quantifying how the heart rate of ectothermic organisms responds to environmental conditions (e.g. water temperature) is important information to quantify their sensitivity to environmental change. Heart rate studies have typically been conducted in lab environments where fish are confined. However, commercially available implantable heart rate biologgers provide the opportunity to study free-swimming fish. Our study aimed to determine the applicability of an implantable device, typically used on fusiform-shaped fish (e.g. salmonids), for a Perciform fish where morphology and anatomy prevent ventral incisions normally used on fusiform-shaped fish. We found that ventrolateral incisions allowed placement near the heart, but efficacy of the loggers was sensitive to their orientation and the positioning of the electrodes. Electrocardiogram detection, signal strength and subsequent heart rate readings were strongly influenced by logger orientation with a significant effect on the quality and quantity of heart rate recordings. We provide details on the surgical procedures and orientation to guide future heart rate biologger studies on Perciform-shaped fish.