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Pietan LL, Spradling TA, Demastes JW. The Mitochondrial Cytochrome Oxidase Subunit I Gene Occurs on a Minichromosome with Extensive Heteroplasmy in Two Species of Chewing Lice, Geomydoecus aurei and Thomomydoecus minor. PLoS One 2016; 11:e0162248. [PMID: 27589589 PMCID: PMC5010254 DOI: 10.1371/journal.pone.0162248] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Accepted: 08/21/2016] [Indexed: 12/02/2022] Open
Abstract
In animals, mitochondrial DNA (mtDNA) typically occurs as a single circular chromosome with 13 protein-coding genes and 22 tRNA genes. The various species of lice examined previously, however, have shown mitochondrial genome rearrangements with a range of chromosome sizes and numbers. Our research demonstrates that the mitochondrial genomes of two species of chewing lice found on pocket gophers, Geomydoecus aurei and Thomomydoecus minor, are fragmented with the 1,536 base-pair (bp) cytochrome-oxidase subunit I (cox1) gene occurring as the only protein-coding gene on a 1,916-1,964 bp minicircular chromosome in the two species, respectively. The cox1 gene of T. minor begins with an atypical start codon, while that of G. aurei does not. Components of the non-protein coding sequence of G. aurei and T. minor include a tRNA (isoleucine) gene, inverted repeat sequences consistent with origins of replication, and an additional non-coding region that is smaller than the non-coding sequence of other lice with such fragmented mitochondrial genomes. Sequences of cox1 minichromosome clones for each species reveal extensive length and sequence heteroplasmy in both coding and noncoding regions. The highly variable non-gene regions of G. aurei and T. minor have little sequence similarity with one another except for a 19-bp region of phylogenetically conserved sequence with unknown function.
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Affiliation(s)
- Lucas L. Pietan
- Department of Biology, University of Northern Iowa, Cedar Falls, Iowa, United States of America
| | - Theresa A. Spradling
- Department of Biology, University of Northern Iowa, Cedar Falls, Iowa, United States of America
| | - James W. Demastes
- Department of Biology, University of Northern Iowa, Cedar Falls, Iowa, United States of America
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Toullec JY, Corre E, Bernay B, Thorne MAS, Cascella K, Ollivaux C, Henry J, Clark MS. Transcriptome and peptidome characterisation of the main neuropeptides and peptidic hormones of a euphausiid: the Ice Krill, Euphausia crystallorophias. PLoS One 2013; 8:e71609. [PMID: 23990964 PMCID: PMC3749230 DOI: 10.1371/journal.pone.0071609] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 07/01/2013] [Indexed: 11/19/2022] Open
Abstract
Background The Ice krill, Euphausia crystallorophias is one of the species at the base of the Southern Ocean food chain. Given their significant contribution to the biomass of the Southern Ocean, it is vitally important to gain a better understanding of their physiology and, in particular, anticipate their responses to climate change effects in the warming seas around Antarctica. Methodology/Principal Findings Illumina sequencing was used to produce a transcriptome of the ice krill. Analysis of the assembled contigs via two different methods, produced 36 new pre-pro-peptides, coding for 61 neuropeptides or peptide hormones belonging to the following families: Allatostatins (A, B et C), Bursicon (α and β), Crustacean Hyperglycemic Hormones (CHH and MIH/VIHs), Crustacean Cardioactive Peptide (CCAP), Corazonin, Diuretic Hormones (DH), the Eclosion Hormone (EH), Neuroparsin, Neuropeptide F (NPF), small Neuropeptide F (sNPF), Pigment Dispersing Hormone (PDH), Red Pigment Concentrating Hormone (RPCH) and finally Tachykinin. LC/MS/MS proteomics was also carried out on eyestalk extracts, which are the major site of neuropeptide synthesis in decapod crustaceans. Results confirmed the presence of six neuropeptides and six precursor-related peptides previously identified in the transcriptome analyses. Conclusions This study represents the first comprehensive analysis of neuropeptide hormones in a Eucarida non-decapod Malacostraca, several of which are described for the first time in a non-decapod crustacean. Additionally, there is a potential expansion of PDH and Neuropeptide F family members, which may reflect certain life history traits such as circadian rhythms associated with diurnal migrations and also the confirmation via mass spectrometry of several novel pre-pro-peptides, of unknown function. Knowledge of these essential hormones provides a vital framework for understanding the physiological response of this key Southern Ocean species to climate change and provides a valuable resource for studies into the molecular phylogeny of these organisms and the evolution of neuropeptide hormones.
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Affiliation(s)
- Jean-Yves Toullec
- UPMC University of Paris 06, UMR 7144 CNRS, Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Roscoff, France
- Centre National de la Recherche Scientifique, UMR 7144, Station Biologique de Roscoff, Roscoff, France
- * E-mail:
| | - Erwan Corre
- UPMC University of Paris 06, FR 2424 CNRS, ABiMS, Analysis and Bioinformatics for Marine Science, Station Biologique de Roscoff, Roscoff, France
| | - Benoît Bernay
- University of Caen Basse Normandie, FRE 3484 CNRS, Biologie des Mollusques Marins et des Ecosystèmes Associés, Caen, France
- University of Caen Basse Normandie, Plateforme PROTEOGEN, Caen, France, SF ICORE 4206
| | - Michael A. S. Thorne
- British Antarctic Survey, Natural Environment Research Council, High Cross, Cambridge, United Kingdom
| | - Kévin Cascella
- UPMC University of Paris 06, UMR 7144 CNRS, Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Roscoff, France
- Centre National de la Recherche Scientifique, UMR 7144, Station Biologique de Roscoff, Roscoff, France
| | - Céline Ollivaux
- UPMC University of Paris 06, UMR 7150 CNRS, Mer et Santé, Station Biologique de Roscoff, Roscoff, France
- Centre National de la Recherche Scientifique, UMR 7150, Station Biologique de Roscoff, Roscoff, France
- Université Européenne de Bretagne, UEB, France
| | - Joël Henry
- University of Caen Basse Normandie, FRE 3484 CNRS, Biologie des Mollusques Marins et des Ecosystèmes Associés, Caen, France
- University of Caen Basse Normandie, Plateforme PROTEOGEN, Caen, France, SF ICORE 4206
| | - Melody S. Clark
- British Antarctic Survey, Natural Environment Research Council, High Cross, Cambridge, United Kingdom
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