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Potential changes in the distributions of Near Eastern fire salamander (Salamandra infraimmaculata) in response to historical, recent and future climate change in the Near and Middle East: Implication for conservation and management. Glob Ecol Conserv 2021. [DOI: 10.1016/j.gecco.2021.e01730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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Cayuela H, Olgun K, Angelini C, Üzüm N, Peyronel O, Miaud C, Avcı A, Lemaitre JF, Schmidt BR. Slow life-history strategies are associated with negligible actuarial senescence in western Palaearctic salamanders. Proc Biol Sci 2019; 286:20191498. [PMID: 31455192 DOI: 10.1098/rspb.2019.1498] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Actuarial senescence has been viewed for a long time as an inevitable and uniform process. However, the work on senescence has mainly focused on endotherms with deterministic growth and low regeneration capacity during the adult stage, leading to a strong taxonomic bias in the study of ageing. Recent studies have highlighted that senescence could indeed display highly variable trajectories that correlate with species life-history traits. Slow life histories and indeterminate growth seem to be associated with weak and late senescence. Furthermore, high regenerative abilities could lead to negligible senescence in ectotherms. However, demographic data for species that would allow testing of these hypotheses are scarce. Here, we investigated senescence patterns in 'true salamanders' from the western Palaearctic. Our results showed that salamanders have slow life histories and that they experience negligible senescence. This pattern was consistent at both intra- and interspecific levels, suggesting that the absence of senescence may be a phylogenetically conserved trait. The regenerative capacities of salamanders, in combination with other physiological and developmental features such as an indeterminate growth and a low metabolic rate, probably explain why these small ectotherms have lifespans similar to that of large endotherms and, in contrast with most amniotes, undergo negligible senescence. Our study seriously challenges the idea that senescence is a ubiquitous phenomenon in the tree of life.
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Affiliation(s)
- Hugo Cayuela
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Quebec, Canada G1V 0A6
| | - Kurtuluş Olgun
- Department of Biology, Faculty of Arts and Sciences, Adnan Menderes University, Aydin, Turkey
| | - Claudio Angelini
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Quebec, Canada G1V 0A6
| | - Nazan Üzüm
- Department of Biology, Faculty of Arts and Sciences, Adnan Menderes University, Aydin, Turkey
| | - Olivier Peyronel
- Syndicat de gestion des gorges de l'Ardèche, 07700 Saint-Remèze, France
| | - Claude Miaud
- PSL Research University, CEFE UMR 5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, EPHE, Biogéographie et Ecologie des vertébrés, Montpellier, France
| | - Aziz Avcı
- Department of Biology, Faculty of Arts and Sciences, Adnan Menderes University, Aydin, Turkey
| | - Jean-François Lemaitre
- CNRS, Laboratoire de Biométrie et Biologie Évolutive UMR 5558, Université Lyon 1, 69622 Villeurbanne, France
| | - Benedikt R Schmidt
- Institut für Evolutionsbiologie und Umweltwissenschaften, Universität Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.,Info fauna karch, UniMail, Bâtiment G, Bellevaux 51, 2000 Neuchâtel, Switzerland
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Erler P, Sweeney A, Monaghan JR. Regulation of Injury-Induced Ovarian Regeneration by Activation of Oogonial Stem Cells. Stem Cells 2016; 35:236-247. [PMID: 28028909 DOI: 10.1002/stem.2504] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 08/25/2016] [Accepted: 09/06/2016] [Indexed: 01/14/2023]
Abstract
Some animals have the ability to generate large numbers of oocytes throughout life. This raises the question whether persistent adult germline stem cell populations drive continuous oogenesis and whether they are capable of mounting a regenerative response after injury. Here we demonstrate the presence of adult oogonial stem cells (OSCs) in the adult axolotl salamander ovary and show that ovarian injury induces OSC activation and functional regeneration of the ovaries to reproductive capability. Cells that have morphological similarities to germ cells were identified in the developing and adult ovaries via histological analysis. Genes involved in germ cell maintenance including Vasa, Oct4, Sox2, Nanog, Bmp15, Piwil1, Piwil2, Dazl, and Lhx8 were expressed in the presumptive OSCs. Colocalization of Vasa protein with H3 mitotic marker showed that both oogonial and spermatogonial adult stem cells were mitotically active. Providing evidence of stemness and viability of adult OSCs, enhanced green fluorescent protein (EGFP) adult OSCs grafted into white juvenile host gonads gave rise to EGFP OSCs, and oocytes. Last, the axolotl ovaries completely regenerated after partial ovariectomy injury. During regeneration, OSC activation resulted in rapid differentiation into new oocytes, which was demonstrated by Vasa+ /BrdU+ coexpression. Furthermore, follicle cell proliferation promoted follicle maturation during ovarian regeneration. Overall, these results show that adult oogenesis occurs via proliferation of endogenous OSCs in a tetrapod and mediates ovarian regeneration. This study lays the foundations to elucidate mechanisms of ovarian regeneration that will assist regenerative medicine in treating premature ovarian failure and reduced fertility. Stem Cells 2017;35:236-247.
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Affiliation(s)
- Piril Erler
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Alexandra Sweeney
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - James R Monaghan
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
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Pewhom A, Chumnanpuen P, Muikham I, Chatchavalvanich K, Srakaew N. Microscopic structures of the ovary and female genital ducts of Supachai's caecilian,Ichthyophis supachaiiTaylor, 1960 (Amphibia: Gymnophiona). ACTA ZOOL-STOCKHOLM 2015. [DOI: 10.1111/azo.12139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Akkanee Pewhom
- Department of Zoology; Faculty of Science; Kasetsart University; Bangkok 10900 Thailand
| | - Pramote Chumnanpuen
- Department of Zoology; Faculty of Science; Kasetsart University; Bangkok 10900 Thailand
| | - Itsares Muikham
- Department of Zoology; Faculty of Science; Kasetsart University; Bangkok 10900 Thailand
| | | | - Nopparat Srakaew
- Department of Zoology; Faculty of Science; Kasetsart University; Bangkok 10900 Thailand
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Vasserman G, Schneidman E, Segev R. Adaptive colour contrast coding in the salamander retina efficiently matches natural scene statistics. PLoS One 2013; 8:e79163. [PMID: 24205373 PMCID: PMC3813611 DOI: 10.1371/journal.pone.0079163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 09/19/2013] [Indexed: 11/19/2022] Open
Abstract
The visual system continually adjusts its sensitivity to the statistical properties of the environment through an adaptation process that starts in the retina. Colour perception and processing is commonly thought to occur mainly in high visual areas, and indeed most evidence for chromatic colour contrast adaptation comes from cortical studies. We show that colour contrast adaptation starts in the retina where ganglion cells adjust their responses to the spectral properties of the environment. We demonstrate that the ganglion cells match their responses to red-blue stimulus combinations according to the relative contrast of each of the input channels by rotating their functional response properties in colour space. Using measurements of the chromatic statistics of natural environments, we show that the retina balances inputs from the two (red and blue) stimulated colour channels, as would be expected from theoretical optimal behaviour. Our results suggest that colour is encoded in the retina based on the efficient processing of spectral information that matches spectral combinations in natural scenes on the colour processing level.
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Affiliation(s)
- Genadiy Vasserman
- Department of Life Sciences and the Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Elad Schneidman
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel
| | - Ronen Segev
- Department of Life Sciences and the Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Mali LB, Bulog B. Ultrastructure of previtellogene oocytes in the neotenic cave salamander Proteus anguinus anguinus (Amphibia, Urodela, Proteidae). PROTOPLASMA 2010; 246:33-39. [PMID: 20177720 DOI: 10.1007/s00709-010-0117-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Accepted: 01/20/2010] [Indexed: 05/28/2023]
Abstract
Oogenesis in the neotenic, cave dwelling salamander Proteus anguinus anguinus has not been studied yet, and this study provides a detailed description of the early growth of the oocytes. Early previtellogene oocytes ranging from 100 to 600 µm in diameter were examined by light and transmission electron microscopy. The oocytes were divided into two stages based on size, color, and histology. Stage I oocytes can be identified by their transparent cytoplasm and a homogenous juxtanuclear mass, composed of numerous lipid droplets and mitochondria. Stage II oocytes are no longer transparent and have increased in diameter to 300- 600 µm, and many cortical alveoli differing in size have appeared. The common and most predominant ultrastructural characteristics of both stages of previtellogene oocytes are extensive quantities of smooth membrane, numerous mitochondria, and lipid droplets, as well as abundant free ribosomes. Myeline-like structures and remarkable annulate lamellae of closely packed membrane stacks are also frequently observed. Previtellogenic oocytes are the most predominant oocytes in the ovaries of Proteus, and while they possess certain structural characteristics typical for other amphibians, some features are unique and could result from adaptation to the subterranean environment.
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Affiliation(s)
- Lilijana Bizjak Mali
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111, 1000, Ljubljana, Slovenia.
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Warburg MR. Studies on 74 half‐sib larval cohorts born to individually identifiable
Salamandra infraimmaculata
females belonging to a single population, a long‐term study. J Zool (1987) 2010. [DOI: 10.1111/j.1469-7998.2009.00666.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M. R. Warburg
- Department of Biology, Technion‐Israel Institute of Technology, Haifa, Israel
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Beyo RS, Sreejith P, Divya L, Oommen OV, Akbarsha MA. Assembly of ovarian follicles in the caecilians Ichthyophis tricolor and Gegeneophis ramaswamii: light and transmission electron microscopic study. ZYGOTE 2007; 15:199-213. [PMID: 17637101 DOI: 10.1017/s0967199407004327] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Though much is known about various aspects of reproductive biology of amphibia, there is little information on the cellular and mechanistic basis of assembly of ovarian follicles in this group. This is especially true of the caecilians. Therefore, taking advantage of the abundant distribution of caecilians in the Western Ghats of India, two species of caecilians, Ichthyophis tricolor and Gegeneophis ramaswamii, were subjected to light and transmission electron microscopic analysis to trace the sequential changes during the assembly of ovarian follicles. The paired ovaries of these caecilians are elongated sac-like structures each including numerous vitellogenic follicles. The follicles are connected by a connective tissue stroma. This stroma contains nests of oogonia, primary oocytes and pregranulosa cells as spatially separated nests. During assembly of follicles the oocytes increase in size and enter the meiotic prophase when the number of nucleoli in the nucleus increases. The mitochondrial cloud or Balbiani vitelline body, initially localized at one pole of the nucleus, disperses through out the cytoplasm subsequently. Synaptonemal complexes are prominent in the pachytene stage oocytes. The pregranulosa cells migrate through the connective tissue fibrils of the stroma and arrive at the vicinity of the meiotic prophase oocytes. On contacting the oocyte, the pregranulosa cells become cuboidal in shape, wrap the diplotene stage oocyte as a discontinuous layer and increase the content of cytoplasmic organelles and inclusions. The oocytes increase in size and are arrested in diplotene when the granulosa cells become flat and form a continuous layer. Soon a perivitelline space appears between the oolemma and granulosa cells, completing the process of assembly of follicles. Thus, the events in the establishment of follicles in the caecilian ovary are described.
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Affiliation(s)
- R S Beyo
- Department of Zoology, University of Kerala, Kariavattom 695 581, Thiruvananthapuram, India
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