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Irene Salinas - One of the best experts on this subject based on the ideXlab platform.
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effects of experimental terrestrialization on the skin mucus proteome of african Lungfish protopterus dolloi
Frontiers in Immunology, 2018Co-Authors: Ryan D Heimroth, Elisa Casadei, Irene SalinasAbstract:Animal mucosal barriers constantly interact with the external environment and this interaction is markedly different in aquatic and terrestrial environments. Transitioning from water to land was a critical step in vertebrate evolution but the immune adaptations that mucosal barriers such as the skin underwent during that process are essentially unknown. Vertebrate animals such as the African Lungfish have a bimodal life, switching from freshwater to terrestrial habitats when environmental conditions are not favorable. African Lungfish skin mucus secretions contribute to the terrestrialization process by forming a cocoon that surrounds and protect the Lungfish body. The goal of this study is to characterize the skin mucus immunoproteome of African Lungfish, Protopterus dolloi, before and during the induction phase of terrestrialization as well as the immunoproteome of the gill mucus during the terrestrialization induction phase. Using LC-MS/MS, we identified a total of 974 proteins using a Lungfish Illumina RNA-seq database, 1256 proteins from previously published Lungfish Sequence Read Archive (SRA) and 880 proteins using a Lungfish 454 RNA-seq database for annotation in the three samples analyzed (free-swimming skin mucus, terrestrialized skin mucus and terrestrialized gill mucus). The terrestrialized skin mucus proteome was enriched in proteins with known antimicrobial functions such as histones and S100 proteins compared to free-swimming skin mucus. In support, gene ontology analyses showed that the terrestrialized skin mucus proteome has predicted functions in processes such as viral process, defense response to Gram negative bacterium and tumor necrosis factor mediated signaling. Importantly, we observed a switch in immunoglobulin heavy chain secretion upon terrestrialization, with IgW1L and IgM1 present in free-swimming skin mucus and IgW1L, IgM1 and IgM2 in terrestrialized skin mucus. Combined, these results indicate an increase investment in the production of unique immune molecules in P. dolloi skin mucus in response to terrestrialization that likely better protect Lungfish against external aggressors found in land.
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Table_5_Effects of Experimental Terrestrialization on the Skin Mucus Proteome of African Lungfish (Protopterus dolloi).XLSX
2018Co-Authors: Ryan D Heimroth, Elisa Casadei, Irene SalinasAbstract:Animal mucosal barriers constantly interact with the external environment, and this interaction is markedly different in aquatic and terrestrial environments. Transitioning from water to land was a critical step in vertebrate evolution, but the immune adaptations that mucosal barriers such as the skin underwent during that process are essentially unknown. Vertebrate animals such as the African Lungfish have a bimodal life, switching from freshwater to terrestrial habitats when environmental conditions are not favorable. African Lungfish skin mucus secretions contribute to the terrestrialization process by forming a cocoon that surrounds and protects the Lungfish body. The goal of this study was to characterize the skin mucus immunoproteome of African Lungfish, Protopterus dolloi, before and during the induction phase of terrestrialization as well as the immunoproteome of the gill mucus during the terrestrialization induction phase. Using LC-MS/MS, we identified a total of 974 proteins using a Lungfish Illumina RNA-seq database, 1,256 proteins from previously published Lungfish sequence read archive and 880 proteins using a Lungfish 454 RNA-seq database for annotation in the three samples analyzed (free-swimming skin mucus, terrestrialized skin mucus, and terrestrialized gill mucus). The terrestrialized skin mucus proteome was enriched in proteins with known antimicrobial functions such as histones and S100 proteins compared to free-swimming skin mucus. In support, gene ontology analyses showed that the terrestrialized skin mucus proteome has predicted functions in processes such as viral process, defense response to Gram-negative bacterium, and tumor necrosis factor-mediated signaling. Importantly, we observed a switch in immunoglobulin heavy chain secretion upon terrestrialization, with IgW1 long form (IgW1L) and IgM1 present in free-swimming skin mucus and IgW1L, IgM1, and IgM2 in terrestrialized skin mucus. Combined, these results indicate an increase in investment in the production of unique immune molecules in P. dolloi skin mucus in response to terrestrialization that likely better protects Lungfish against external aggressors found in land.
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Data_Sheet_4_Effects of Experimental Terrestrialization on the Skin Mucus Proteome of African Lungfish (Protopterus dolloi).XLSX
2018Co-Authors: Ryan D Heimroth, Elisa Casadei, Irene SalinasAbstract:Animal mucosal barriers constantly interact with the external environment, and this interaction is markedly different in aquatic and terrestrial environments. Transitioning from water to land was a critical step in vertebrate evolution, but the immune adaptations that mucosal barriers such as the skin underwent during that process are essentially unknown. Vertebrate animals such as the African Lungfish have a bimodal life, switching from freshwater to terrestrial habitats when environmental conditions are not favorable. African Lungfish skin mucus secretions contribute to the terrestrialization process by forming a cocoon that surrounds and protects the Lungfish body. The goal of this study was to characterize the skin mucus immunoproteome of African Lungfish, Protopterus dolloi, before and during the induction phase of terrestrialization as well as the immunoproteome of the gill mucus during the terrestrialization induction phase. Using LC-MS/MS, we identified a total of 974 proteins using a Lungfish Illumina RNA-seq database, 1,256 proteins from previously published Lungfish sequence read archive and 880 proteins using a Lungfish 454 RNA-seq database for annotation in the three samples analyzed (free-swimming skin mucus, terrestrialized skin mucus, and terrestrialized gill mucus). The terrestrialized skin mucus proteome was enriched in proteins with known antimicrobial functions such as histones and S100 proteins compared to free-swimming skin mucus. In support, gene ontology analyses showed that the terrestrialized skin mucus proteome has predicted functions in processes such as viral process, defense response to Gram-negative bacterium, and tumor necrosis factor-mediated signaling. Importantly, we observed a switch in immunoglobulin heavy chain secretion upon terrestrialization, with IgW1 long form (IgW1L) and IgM1 present in free-swimming skin mucus and IgW1L, IgM1, and IgM2 in terrestrialized skin mucus. Combined, these results indicate an increase in investment in the production of unique immune molecules in P. dolloi skin mucus in response to terrestrialization that likely better protects Lungfish against external aggressors found in land.
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Image_1_Effects of Experimental Terrestrialization on the Skin Mucus Proteome of African Lungfish (Protopterus dolloi).TIFF
2018Co-Authors: Ryan D Heimroth, Elisa Casadei, Irene SalinasAbstract:Animal mucosal barriers constantly interact with the external environment, and this interaction is markedly different in aquatic and terrestrial environments. Transitioning from water to land was a critical step in vertebrate evolution, but the immune adaptations that mucosal barriers such as the skin underwent during that process are essentially unknown. Vertebrate animals such as the African Lungfish have a bimodal life, switching from freshwater to terrestrial habitats when environmental conditions are not favorable. African Lungfish skin mucus secretions contribute to the terrestrialization process by forming a cocoon that surrounds and protects the Lungfish body. The goal of this study was to characterize the skin mucus immunoproteome of African Lungfish, Protopterus dolloi, before and during the induction phase of terrestrialization as well as the immunoproteome of the gill mucus during the terrestrialization induction phase. Using LC-MS/MS, we identified a total of 974 proteins using a Lungfish Illumina RNA-seq database, 1,256 proteins from previously published Lungfish sequence read archive and 880 proteins using a Lungfish 454 RNA-seq database for annotation in the three samples analyzed (free-swimming skin mucus, terrestrialized skin mucus, and terrestrialized gill mucus). The terrestrialized skin mucus proteome was enriched in proteins with known antimicrobial functions such as histones and S100 proteins compared to free-swimming skin mucus. In support, gene ontology analyses showed that the terrestrialized skin mucus proteome has predicted functions in processes such as viral process, defense response to Gram-negative bacterium, and tumor necrosis factor-mediated signaling. Importantly, we observed a switch in immunoglobulin heavy chain secretion upon terrestrialization, with IgW1 long form (IgW1L) and IgM1 present in free-swimming skin mucus and IgW1L, IgM1, and IgM2 in terrestrialized skin mucus. Combined, these results indicate an increase in investment in the production of unique immune molecules in P. dolloi skin mucus in response to terrestrialization that likely better protects Lungfish against external aggressors found in land.
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characterization of t cell receptors in african Lungfish protopterus dolloi and their role in mucosal immunity
Fish & Shellfish Immunology, 2016Co-Authors: Susana Magadan, Luca Tacchi, R Heimroth, Irene SalinasAbstract:Lungfish (Dipnoi) are the closest relatives to all living tetrapods. The immune system of this group of species is particularly interesting since it may provide insights about the changes in the immune system associated with the water-to-land transition of vertebrates. We recently reported all the immunoglobulin molecules expressed by two different African Lungfish species, Protopterus dolloi and P. annectens. However, to date, no studies on T cell receptor (TCR) molecules have been conducted in Lungfish. Using deep sequencing databases as well as a RACE approach, we have identified TCR, TCR, TCR and TCR sequences in P. dolloi. Amino acid sequence analysis and phylogenetic trees were performed and results support that Dipnoi are more closely related to tetrapods. V segment usage by each TCR gene in P. dolloi systemic versus mucosa-associated lymphoid tissue is presented. Constitutive expression studies in control Lungfish indicate a low expression of TCR in all tissues tested. In response to nasal infection with Edwardsiella ictaluri, increased expression of TCR, TCR and TCR but not TCR was detected in the pre-pyloric spleen and gut of P. dolloi. On the other hand, significant decreased expression in the same three genes was observed in the lung and post-pyloric spleen. Future studies will complete our current understanding of TCR evolution in vertebrates and may shed light to the unique features of the tetrapod T cell system.
Minoru Uchiyama - One of the best experts on this subject based on the ideXlab platform.
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cloning and expression of the epithelial sodium channel and its role in osmoregulation of aquatic and estivating african Lungfish protopterus annectens
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2015Co-Authors: Minoru Uchiyama, Sachika Shibuya, Norifumi Konno, Satoshi NogamiAbstract:The epithelial sodium channel (ENaC) is a sodium (Na + )-selective aldosterone-stimulated ion channel involved in Na + transport homeostasis of tetrapods. We examined full-length cDNA sequences and tissue distributions of ENaCα, ENaCβ, and ENaCγ subunits in the African Lungfish Protopterus annectens . Protopterus ENaC ( p ENaC) comprises 3 subunits: p ENaCα, p ENaCβ, and p ENaCγ. p ENaCα, p ENaCβ, and p ENaCγ subunits are closely related to α, β, and γ subunits of the Australian Lungfish Neoceratodus forsteri ENaC ( n ENaC), respectively. Three ENaC subunit mRNAs were highly expressed in the gills and moderately expressed in the kidney and rectum of P. annectens . During estivation for 2–4 weeks and 2–3 months, plasma Na + concentration was relatively stable, but plasma urea concentration significantly increased in comparison with the control fish kept in a freshwater environment. Plasma aldosterone concentration and mRNA expression of the ENaCα subunit gradually and significantly decreased in the gills and kidney after 2 months of estivation. Thus, aldosterone-dependent Na + absorption via ENaC probably exists in the epithelial cells of osmoregulatory organs of Lungfish kept in fresh water, whereas plasma Na + concentration may be maintained by a mechanism independent of aldosterone-ENaC axis during estivation in Lungfish.
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vasotocin v2 type receptor aquaporin axis exists in african Lungfish kidney but is functional only in terrestrial condition
Endocrinology, 2010Co-Authors: Norifumi Konno, Susumu Hyodo, Yoko Yamaguchi, Kouhei Matsuda, Minoru UchiyamaAbstract:The vasopressin/vasotocin (VT)-V2-type receptor (V2R)-aquaporin (AQP)-2 axis plays a pivotal role in renal water reabsorption in tetrapods. It is widely thought that this axis evolved with the emergence of the tetrapods, reflecting a requirement of water retention in terrestrial environment. Here we report that Lungfish, the closest living relatives of tetrapods, already possess a system similar to the VT-V2R-AQP2 axis in the kidney, but the system is functional only in the terrestrial estivating condition. We cloned a novel AQP paralogous to AQP0. The water permeability of Xenopus oocytes was increased by injection with the AQP cRNA and was further facilitated by preincubation with cAMP. In the kidney of estivating Lungfish, the AQP protein was localized on the apical plasma membrane of the late distal tubule and was colocalized with basolateral V2R. By contrast, we found only little expression of the AQP mRNA and protein in the kidney of Lungfish in aquatic condition. The expression levels of mRNA and protein were dramatically increased during estivation and decreased again by reacclimation of estivating Lungfish to water. The AQP mRNA levels positively correlated with the VT mRNA levels in the hypothalamus, suggesting that the AQP exerts tubular antidiuretic action under control of VT. Because the tetrapod AQP2/AQP5 lineage is considered to be evolved from duplication of an AQP0 gene, the paralogous AQP0 in the Lungfish probably represents ancestral molecule for tetrapod AQP2.
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african Lungfish protopterus annectens possess an arginine vasotocin receptor homologous to the tetrapod v2 type receptor
The Journal of Experimental Biology, 2009Co-Authors: Norifumi Konno, Susumu Hyodo, Yoko Yamaguchi, Hiroyuki Kaiya, Mikiya Miyazato, Kouhei Matsuda, Minoru UchiyamaAbstract:SUMMARY In tetrapods, arginine vasopressin and its counterpart, arginine vasotocin (AVT), are involved in renal water conservation through vascular V1a-type and tubular V2-type receptors, and only the former has thus far been cloned in fish. We successfully cloned the V1a-type and V2-type AVT receptor from the kidney of the African Lungfish, Protopterus annectens , and the deduced amino acid sequences exhibited high homology with amphibian V1a- and V2-type receptors, respectively. Functional analysis showed that AVT addition to CHO cells transfected with Lungfish V1a-type receptor increased [Ca 2+ ] i in a concentration-dependent manner, whereas CHO cells transfected with Lungfish V2-type receptor responded with cAMP accumulation after AVT stimulation. Lungfish V2-type receptor mRNA was strongly expressed in the heart and kidney, while V1a-type receptor mRNA was ubiquitously expressed in all the tissues examined. In the kidney, immunohistochemistry using a specific antibody to Lungfish V2-type receptor showed localization in the basolateral area of the cells in the late part of the distal tubules. Artificial estivation (EST) for 90 days significantly increased plasma osmolality and sodium and urea concentrations. There was no significant difference in the V2-type receptor mRNA and protein expression levels in the kidney between the freshwater and EST Lungfish, while the AVT precursor mRNA level in the hypothalamus was remarkably higher in the EST Lungfish. Our results indicate that African Lungfish possess a functional V2-type receptor similar to that in tetrapods, suggesting that elevated plasma AVT during estivation exerts a renal tubular antidiuretic effect through the V2-type receptor expressed in the distal segments of Lungfish kidney.
Jean M.p. Joss - One of the best experts on this subject based on the ideXlab platform.
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evolution of the australian Lungfish neoceratodus forsteri genome a major role for cr1 and l2 line elements
Molecular Biology and Evolution, 2012Co-Authors: Cushla J Metcalfe, Jean M.p. Joss, Jonathan Filee, Isabelle Germon, Didier CasaneAbstract:Haploid genomes greater than 25,000 Mb are rare, within the animals only the Lungfish and some of the salamanders and crustaceans are known to have genomes this large. There is very little data on the structure of genomes this size. It is known, however, that for animal genomes up to 3,000 Mb, there is in general a good correlation between genome size and the percent of the genome composed of repetitive sequence and that this repetitive component is highly dynamic. In this study, we sampled the Australian Lungfish genome using three mini-genomic libraries and found that with very little sequence, the results converged on an estimate of 40% of the genome being composed of recognizable transposable elements (TEs), chiefly from the CR1 and L2 long interspersed nuclear element clades. We further characterized the CR1 and L2 elements in the Lungfish genome and show that although most CR1 elements probably represent recent amplifications, the L2 elements are more diverse and are more likely the result of a series of amplifications. We suggest that our sampling method has probably underestimated the recognizable TE content. However, on the basis of the most likely sources of error, we suggest that this very large genome is not largely composed of recently amplified, undetected TEs but may instead include a large component of older degenerate TEs. Based on these estimates, and on Thomson's (Thomson K. 1972. An attempt to reconstruct evolutionary changes in the cellular DNA content of Lungfish. J Exp Zool. 180:363-372) inference that in the lineage leading to the extant Australian Lungfish, there was massive increase in genome size between 350 and 200 mya, after which the size of the genome changed little, we speculate that the very large Australian Lungfish genome may be the result of a massive amplification of TEs followed by a long period with a very low rate of sequence removal and some ongoing TE activity.
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Is Palaeospondylus gunni a fossil larval Lungfish? Insights from Neoceratodus forsteri development.
Journal of experimental zoology. Part B Molecular and developmental evolution, 2007Co-Authors: Jean M.p. Joss, Zerina JohansonAbstract:The enigmatic Devonian fossil Palaeospondylus gunni was identified as a larval form, metamorphosing into the Lungfish Dipterus valenciennesi. Morphological features used to identify P. gunni as a larval Lungfish include enlarged cranial ribs, rudimentary limb girdles, and absence of teeth. However, this combination of features does not characterize the extant Lungfish Neoceratodus forsteri, even at very young stages, nor early stages of Devonian and younger fossil Lungfish. Absence of teeth is problematic because early ontogenetic stages of fossil and living Lungfish possess full dentitions including marginal teeth. Also problematic are cranial ribs as a defining character of Lungfish, as these also occur in certain actinopterygians. It is argued that Neoceratodus is an obligate neotene (reproductively mature larva), with the implication that metamorphosis was a feature of the ontogeny of early Lungfish. Pedomorphic characters have been recognized in Neoceratodus and other post-Devonian Lungfish, including large cells and correspondingly large genome size; these latter characters correlate with neoteny in salamanders. Small cells preserved in fossil bone suggest that Devonian Lungfish had a smaller genome than post-Devonian Lungfish, implying that they were not neotenic. As fossil Lungfish cell sizes (and genomes) increased in the late Paleozoic, the diversity of Lungfish morphologies decreased, so that taxa like Sagenodus and Conchopoma show morphological similarity to Neoceratodus, marking a point in phylogeny at which metamorphosis was potentially lost. Since ancestral larval characters are retained in neotenic adults, we predict that Devonian larvae should resemble these post-Devonian taxa, a prediction which Palaeospondylus does not fulfill.
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Lungfish evolution and development.
General and comparative endocrinology, 2005Co-Authors: Jean M.p. JossAbstract:The first vertebrates recognizable as tetrapods appeared in the mid-Devonian. It is generally agreed that their ancestors were lobe-finned fish. What is not agreed is how close either of the extant groups of lobe-finned fish, Lungfish or coelacanths, is to the actual ancestor of the tetrapods. The soft anatomy of living Lungfish shares many similarities with that of living amphibians. Many of these similarities are not present in either coelacanths or any members of the other extant bony fish group, the ray-finned fishes. Many very well preserved Lungfish from the Devonian possess specialized features that would appear to exclude them from being ancestral to tetrapods. I am hypothesizing that Lungfish in the Devonian may have included metamorphosis in their life cycle and that neoteny in some species may have been an early corollary. These reproductively mature neotenous Lungfish would not have had the specialised features of metamorphosed adults. Fossils of these neotenous forms may have more closely resembled the tetrapod ancestral lobe-finned fish, currently believed to be a panderichthiad fish. Living Lungfish have a number of larval features, which suggest paedomorphosis. Also of significance is the very large genome of living Lungfish, which, in urodele amphibians, is a feature correlated with neoteny. Our current knowledge of the thyroid axis in the Lungfish, Neoceratodus forsteri, is consistent with neoteny in amphibians, but the only Devonian fossil considered to be a larval Lungfish bears no resemblance to living Lungfish or to panderichthiads. The enigmatic phylogenetic relationship of Lungfish with the first tetrapods remains, but the hunt for other forms of larval Devonian Lungfish is on!
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Deiodinase type III in the Australian Lungfish, Neoceratodus forsteri.
General and comparative endocrinology, 2004Co-Authors: Margareta Sutija, Terrence J. Longhurst, Jean M.p. JossAbstract:Abstract This work presents characterisation of deiodinase type III (D3) mRNA as cDNA and the tissue distribution of D3 mRNA in the Australian Lungfish, Neoceratodus forsteri . We have identified the full length of a ∼1.4 kb D3 mRNA in the liver, which has a single in-frame UGA codon and a selenocysteine insertion sequence (SECIS) form 2 in the 3 ′ -UTR. Lungfish D3 mRNA was expressed in all tested tissues (liver, lung, kidney, brain, heart, and gills) as demonstrated by Northern blot analyses. PCR conducted on genomic DNA indicated that the Lungfish D3 is a single exon gene. Also, we present enzymatic characteristics of this exclusively IRD enzyme, have determined its substrate preference, DTT cofactor requirements, PTU inhibition, and kinetic properties. These results indicate that Lungfish D3 has the typical enzymatic characteristics of vertebrate D3 enzymes.
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Cranial neural crest cell migration in the Australian Lungfish, Neoceratodus forsteri
Evolution & development, 2000Co-Authors: Pierre Falck, Jean M.p. Joss, Lennart OlssonAbstract:SUMMARY A crucial role for the cranial neural crest in head development has been established for both actinopterygian fishes and tetrapods. It has been claimed, however, that the neural crest is unimportant for head development in the Australian Lungfish (Neoceratodus forsteri ), a member of the group (Dipnoi) which is commonly considered to be the living sister group of the tetrapods. In the present study, we used scanning electron microscopy to study cranial neural crest development in the Australian Lungfish. Our results, contrary to those of Kemp, show that cranial neural crest cells do emerge and migrate in the Australian Lungfish in the same way as in other vertebrates, forming mandibular, hyoid, and branchial streams. The major difference is in the timing of the onset of cranial neural crest migration. It is delayed in the Australian Lungfish in comparison with their living sister group the Lissamphibia. Furthermore, the delay in timing between the emergence of the hyoid and branchial crest streams is very long, indicating a steeper anterior-posterior gradient than in amphibians. We are now extending our work on Lungfish head development to include experimental studies (ablation of selected streams of neural crest cells) and fate mapping (using fluoresent tracer dyes such as DiI) to document the normal fate as well as the role in head patterning of the cranial neural crest in the Australian Lungfish.
Norifumi Konno - One of the best experts on this subject based on the ideXlab platform.
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cloning and expression of the epithelial sodium channel and its role in osmoregulation of aquatic and estivating african Lungfish protopterus annectens
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2015Co-Authors: Minoru Uchiyama, Sachika Shibuya, Norifumi Konno, Satoshi NogamiAbstract:The epithelial sodium channel (ENaC) is a sodium (Na + )-selective aldosterone-stimulated ion channel involved in Na + transport homeostasis of tetrapods. We examined full-length cDNA sequences and tissue distributions of ENaCα, ENaCβ, and ENaCγ subunits in the African Lungfish Protopterus annectens . Protopterus ENaC ( p ENaC) comprises 3 subunits: p ENaCα, p ENaCβ, and p ENaCγ. p ENaCα, p ENaCβ, and p ENaCγ subunits are closely related to α, β, and γ subunits of the Australian Lungfish Neoceratodus forsteri ENaC ( n ENaC), respectively. Three ENaC subunit mRNAs were highly expressed in the gills and moderately expressed in the kidney and rectum of P. annectens . During estivation for 2–4 weeks and 2–3 months, plasma Na + concentration was relatively stable, but plasma urea concentration significantly increased in comparison with the control fish kept in a freshwater environment. Plasma aldosterone concentration and mRNA expression of the ENaCα subunit gradually and significantly decreased in the gills and kidney after 2 months of estivation. Thus, aldosterone-dependent Na + absorption via ENaC probably exists in the epithelial cells of osmoregulatory organs of Lungfish kept in fresh water, whereas plasma Na + concentration may be maintained by a mechanism independent of aldosterone-ENaC axis during estivation in Lungfish.
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vasotocin v2 type receptor aquaporin axis exists in african Lungfish kidney but is functional only in terrestrial condition
Endocrinology, 2010Co-Authors: Norifumi Konno, Susumu Hyodo, Yoko Yamaguchi, Kouhei Matsuda, Minoru UchiyamaAbstract:The vasopressin/vasotocin (VT)-V2-type receptor (V2R)-aquaporin (AQP)-2 axis plays a pivotal role in renal water reabsorption in tetrapods. It is widely thought that this axis evolved with the emergence of the tetrapods, reflecting a requirement of water retention in terrestrial environment. Here we report that Lungfish, the closest living relatives of tetrapods, already possess a system similar to the VT-V2R-AQP2 axis in the kidney, but the system is functional only in the terrestrial estivating condition. We cloned a novel AQP paralogous to AQP0. The water permeability of Xenopus oocytes was increased by injection with the AQP cRNA and was further facilitated by preincubation with cAMP. In the kidney of estivating Lungfish, the AQP protein was localized on the apical plasma membrane of the late distal tubule and was colocalized with basolateral V2R. By contrast, we found only little expression of the AQP mRNA and protein in the kidney of Lungfish in aquatic condition. The expression levels of mRNA and protein were dramatically increased during estivation and decreased again by reacclimation of estivating Lungfish to water. The AQP mRNA levels positively correlated with the VT mRNA levels in the hypothalamus, suggesting that the AQP exerts tubular antidiuretic action under control of VT. Because the tetrapod AQP2/AQP5 lineage is considered to be evolved from duplication of an AQP0 gene, the paralogous AQP0 in the Lungfish probably represents ancestral molecule for tetrapod AQP2.
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african Lungfish protopterus annectens possess an arginine vasotocin receptor homologous to the tetrapod v2 type receptor
The Journal of Experimental Biology, 2009Co-Authors: Norifumi Konno, Susumu Hyodo, Yoko Yamaguchi, Hiroyuki Kaiya, Mikiya Miyazato, Kouhei Matsuda, Minoru UchiyamaAbstract:SUMMARY In tetrapods, arginine vasopressin and its counterpart, arginine vasotocin (AVT), are involved in renal water conservation through vascular V1a-type and tubular V2-type receptors, and only the former has thus far been cloned in fish. We successfully cloned the V1a-type and V2-type AVT receptor from the kidney of the African Lungfish, Protopterus annectens , and the deduced amino acid sequences exhibited high homology with amphibian V1a- and V2-type receptors, respectively. Functional analysis showed that AVT addition to CHO cells transfected with Lungfish V1a-type receptor increased [Ca 2+ ] i in a concentration-dependent manner, whereas CHO cells transfected with Lungfish V2-type receptor responded with cAMP accumulation after AVT stimulation. Lungfish V2-type receptor mRNA was strongly expressed in the heart and kidney, while V1a-type receptor mRNA was ubiquitously expressed in all the tissues examined. In the kidney, immunohistochemistry using a specific antibody to Lungfish V2-type receptor showed localization in the basolateral area of the cells in the late part of the distal tubules. Artificial estivation (EST) for 90 days significantly increased plasma osmolality and sodium and urea concentrations. There was no significant difference in the V2-type receptor mRNA and protein expression levels in the kidney between the freshwater and EST Lungfish, while the AVT precursor mRNA level in the hypothalamus was remarkably higher in the EST Lungfish. Our results indicate that African Lungfish possess a functional V2-type receptor similar to that in tetrapods, suggesting that elevated plasma AVT during estivation exerts a renal tubular antidiuretic effect through the V2-type receptor expressed in the distal segments of Lungfish kidney.
Axel Meyer - One of the best experts on this subject based on the ideXlab platform.
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Complete Mitochondrial Genome Sequences of the South American and the Australian Lungfish: Testing of the Phylogenetic Performance of Mitochondrial Data Sets for Phylogenetic Problems in Tetrapod Relationships
Journal of Molecular Evolution, 2004Co-Authors: Henner Brinkmann, Angelika Denk, Jürgen Zitzler, Jean J. Joss, Axel MeyerAbstract:We determined the complete nucleotide sequences (16403 and 16572 base pairs, respectively) of the mitochondrial genomes of the South American Lungfish, Lepidosiren paradoxa , and the Australian Lungfish, Neoceratodus forsteri (Sarcopterygii, Dipnoi). The mitochondrial DNA sequences were established in an effort to resolve the debated evolutionary positions of the Lungfish and the coelacanth relative to land vertebrates. Previous molecular phylogenetic studies based on complete mtDNA sequences, including only the African Lungfish, Protopterus dolloi , sequence were able to strongly reject the traditional textbook hypothesis that coelacanths are the closest relatives of land vertebrates. However, these studies were unable to statistically significantly distinguish between the two remaining scenarios: Lungfish as the closest relatives to land vertebrates and Lungfish and coelacanths jointly as their sister group ( Cao et al. 1998 ; Zardoya et al. 1998 ; Zardoya and Meyer 1997a ). Lungfish, coelacanths, and the fish ancestors of the tetrapod lineage all originated within a short time window of about 20 million years, back in the early Devonian (about 380 to 400 million years ago). This short divergence time makes the determination of the phylogenetic relationships among these three lineages difficult. In this study, we attempted to break the long evolutionary branch of Lungfish, in an effort to better resolve the phylogenetic relationships among the three extant sarcopterygian lineages. The gene order of the mitochondrial genomes of the South American and Australian Lungfish conforms to the consensus gene order among gnathostome vertebrates. The phylogenetic analyses of the complete set of mitochondrial proteins (without ND6) suggest that the Lungfish are the closest relatives of the tetrapods, although the support in favor of this scenario is not statistically significant. The two other smaller data sets (tRNA and rRNA genes) give inconsistent results depending on the different reconstruction methods applied and cannot significantly rule out any of the three alternative hypotheses. Nuclear protein-coding genes, which might be better phylogenetic markers for this question, support the Lungfish–tetrapod sister-group relationship ( Brinkmann et al. 2004 ).
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nuclear protein coding genes support Lungfish and not the coelacanth as the closest living relatives of land vertebrates
Proceedings of the National Academy of Sciences of the United States of America, 2004Co-Authors: Henner Brinkmann, Byrappa Venkatesh, Sydney Brenner, Axel MeyerAbstract:The colonization of land by tetrapod ancestors is one of the major questions in the evolution of vertebrates. Despite intense molecular phylogenetic research on this problem during the last 15 years, there is, until now, no statistically supported answer to the question of whether coelacanths or Lungfish are the closest living relatives of tetrapods. We determined DNA sequences of the nuclear-encoded recombination activating genes (Rag1 and Rag2) from all three major Lungfish groups, the Australian Neoceratodis forsteri, the South American Lepidosiren paradoxa and the African Lungfish Protopterus dolloi, and the Indonesian coelacanth Latimeria menadoensis. Phylogenetic analyses of both the single gene and the concatenated data sets of RAG1 and RAG2 found that the Lungfishes are the closest living relatives of the land vertebrates. These results are supported by high bootstrap values, Bayesian posterior probabilities, and likelihood ratio tests.
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the complete nucleotide sequence of the mitochondrial genome of the Lungfish protopterus dolloi supports its phylogenetic position as a close relative of land vertebrates
Genetics, 1996Co-Authors: Rafael Zardoya, Axel MeyerAbstract:The complete DNA sequence (16,646 bp) of the mitochondrial genome of the African Lungfish, Protopterus dolloi, was determined. The evolutionary position of Lungfish as possibly the closest living relative among fish of land vertebrates made its mitochondrial DNA sequence particularly interesting. Its mitochondrial gene order conforms to the consensus vertebrate gene order. Several sequence motifs and secondary structures likely involved in the regulation of the initiation of replication and transcription of the mitochondrial genome are conserved in the Lungfish and are more similar to those of land vertebrates than those of ray-finned fish. A novel feature discovered is that the putative origin of L-strand replication partially overlaps the adjacent tRNA(Cys). The phylogenetic analyses of genes coding for tRNAs and proteins confirm the intermediate phylogenetic position of Lungfish between ray-finned fishes and tetrapods. The complete nucleotide sequence of the African Lungfish mitochondrial genome was used to estimate which mitochondrial genes are most appropriate to elucidate deep branch phylogenies. Only a combined set of either protein or tRNA mitochondrial genes (but not each gene alone) is able to confidently recover the expected phylogeny among vertebrates that have diverged up to but not over ~400 mya.
