1
|
Reinhard S, Kupfer A. Maternal investment in the viviparous caecilian amphibian Typhlonectes natans (Gymnophiona: Typhlonectidae). ZOOL ANZ 2022. [DOI: 10.1016/j.jcz.2021.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
2
|
Zandonà E, Kajin M, Buckup PA, Amaral JR, Souto-Santos ICA, Reznick DN. Mode of maternal provisioning in the fish genus Phalloceros: a variation on the theme of matrotrophy. Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
The placenta is a complex organ that shows high morphological diversity. Among fish, the first vertebrates that have evolved a placenta, the family Poeciliidae exhibits very diverse modes of maternal provisioning even among congeneric species. Here, we investigated the embryonic growth curve across seven recently-described species of the highly diverse genus Phalloceros (Eigenmann, 1907). We also investigated possible intraspecific differences and whether other female characteristics affected embryo mass. We found that embryo mass decreased until around stage 20 and then increased, resulting in a 1.5 to 3-fold mass gain from fertilization to birth. Embryo mass changed non-linearly with stage of development and was affected by species identity (or locality) and female somatic dry mass. This initial loss then gain of embryonic mass during development is unique among other Poeciliidae species and was conserved across populations and species, even though size at birth can vary. Other species instead either lose mass if they lack placentas or gain mass exponentially if they have placentas. The Phalloceros mode of maternal provisioning could thus represent a different form from that seen in other species of Poeciliidae.
Collapse
Affiliation(s)
- Eugenia Zandonà
- Programa de Pós-graduação em Ecologia e Evolução, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ 20550-013, Brazil
| | - Maja Kajin
- Programa de Pós-graduação em Ecologia e Evolução, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ 20550-013, Brazil
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Paulo A Buckup
- Museu Nacional, Universidade Federal do Rio de Janeiro, 20940-040 Rio de Janeiro, RJ, Brazil
| | - Jeferson Ribeiro Amaral
- Programa de Pós-graduação em Ecologia e Evolução, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ 20550-013, Brazil
| | - Igor C A Souto-Santos
- Museu Nacional, Universidade Federal do Rio de Janeiro, 20940-040 Rio de Janeiro, RJ, Brazil
| | - David N Reznick
- Department of Biology, University of California Riverside, Riverside, CA 92521, USA
| |
Collapse
|
3
|
Blackburn DG. The oviparous olm: Analysis & refutation of claims for viviparity in the cave salamander Proteus anguinus (Amphibia: Proteidae). ZOOL ANZ 2019. [DOI: 10.1016/j.jcz.2019.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
4
|
Reinhardt T, Baldauf L, Ilić M, Fink P. Cast away: drift as the main determinant for larval survival in western fire salamanders (Salamandra salamandra) in headwater streams. J Zool (1987) 2018. [DOI: 10.1111/jzo.12581] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- T. Reinhardt
- Institute for Cell Biology and Zoology; Heinrich-Heine-University Düsseldorf; Düsseldorf Germany
| | - L. Baldauf
- Institute of Zoology; University of Cologne; Cologne Germany
| | - M. Ilić
- Institute of Zoology; University of Cologne; Cologne Germany
| | - P. Fink
- Institute for Cell Biology and Zoology; Heinrich-Heine-University Düsseldorf; Düsseldorf Germany
- Institute of Zoology; University of Cologne; Cologne Germany
| |
Collapse
|
5
|
Yokoe M, Takayama-Watanabe E, Saito Y, Kutsuzawa M, Fujita K, Ochi H, Nakauchi Y, Watanabe A. A Novel Cysteine Knot Protein for Enhancing Sperm Motility That Might Facilitate the Evolution of Internal Fertilization in Amphibians. PLoS One 2016; 11:e0160445. [PMID: 27579691 PMCID: PMC5007030 DOI: 10.1371/journal.pone.0160445] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 07/19/2016] [Indexed: 11/26/2022] Open
Abstract
Internal fertilization ensures successful reproduction of tetrapod vertebrates on land, although how this mode of reproduction evolved is unknown. Here, we identified a novel gene encoding sperm motility-initiating substance (SMIS), a key protein for the internal fertilization of the urodele Cynops pyrrhogaster by Edman degradation of an isolated protein and subsequent reverse transcription polymerase chain reaction. The SMIS gene encoded a 150 amino-acid sequence including the cysteine knot (CK) motif. No gene with substantial similarity to the SMIS was in the data bank of any model organisms. An active site of the SMIS was in the C-terminal region of the 2nd loop of CK motif. A synthetic peptide including the active site sequence bound to the midpiece and initiated/enhanced the circular motion of C. pyrrhogaster sperm, which allows penetration of the egg jelly specialized for the internal fertilization of this species. The synthetic peptide bound to whole sperm of Rhacophorus arboreus and enhanced the rotary motion, which is adapted to propel the sperm through egg coat matrix specialized for arboreal reproduction, while it bound to the tip of head and tail of Bufo japonicus sperm, and enhanced the vibratory motion, which is suited to sperm penetration through the egg jelly specialized for the reproduction of that species in freshwater. The polyclonal antibody against the active site of the SMIS specifically bound to egg coat matrix of R. arboreus. These findings suggest that diversification of amphibian reproductive modes accompanies the specialization of egg coat and the adaptation of sperm motility to penetrate the specialized egg coat, and SMIS acts as the sperm motility enhancer of anurans and urodeles that might facilitate to adaptively optimize sperm motility for allowing the establishment of internal fertilization.
Collapse
Affiliation(s)
- Misato Yokoe
- Department of Biology, Faculty of Science, Yamagata University, Kojirakawa, Yamagata, Japan
| | | | - Yoko Saito
- Department of Biology, Faculty of Science, Yamagata University, Kojirakawa, Yamagata, Japan
| | - Megumi Kutsuzawa
- Department of Biology, Faculty of Science, Yamagata University, Kojirakawa, Yamagata, Japan
| | - Kosuke Fujita
- Department of Biology, Faculty of Science, Yamagata University, Kojirakawa, Yamagata, Japan
| | - Haruki Ochi
- School of Medicine, Yamagata University, Iida-Nishi, Yamagata, Japan
| | - Yuni Nakauchi
- Department of Biology, Faculty of Science, Yamagata University, Kojirakawa, Yamagata, Japan
| | - Akihiko Watanabe
- Department of Biology, Faculty of Science, Yamagata University, Kojirakawa, Yamagata, Japan
| |
Collapse
|
6
|
Ostrovsky AN, Lidgard S, Gordon DP, Schwaha T, Genikhovich G, Ereskovsky AV. Matrotrophy and placentation in invertebrates: a new paradigm. Biol Rev Camb Philos Soc 2016; 91:673-711. [PMID: 25925633 PMCID: PMC5098176 DOI: 10.1111/brv.12189] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 03/18/2015] [Accepted: 03/24/2015] [Indexed: 12/29/2022]
Abstract
Matrotrophy, the continuous extra-vitelline supply of nutrients from the parent to the progeny during gestation, is one of the masterpieces of nature, contributing to offspring fitness and often correlated with evolutionary diversification. The most elaborate form of matrotrophy-placentotrophy-is well known for its broad occurrence among vertebrates, but the comparative distribution and structural diversity of matrotrophic expression among invertebrates is wanting. In the first comprehensive analysis of matrotrophy across the animal kingdom, we report that regardless of the degree of expression, it is established or inferred in at least 21 of 34 animal phyla, significantly exceeding previous accounts and changing the old paradigm that these phenomena are infrequent among invertebrates. In 10 phyla, matrotrophy is represented by only one or a few species, whereas in 11 it is either not uncommon or widespread and even pervasive. Among invertebrate phyla, Platyhelminthes, Arthropoda and Bryozoa dominate, with 162, 83 and 53 partly or wholly matrotrophic families, respectively. In comparison, Chordata has more than 220 families that include or consist entirely of matrotrophic species. We analysed the distribution of reproductive patterns among and within invertebrate phyla using recently published molecular phylogenies: matrotrophy has seemingly evolved at least 140 times in all major superclades: Parazoa and Eumetazoa, Radiata and Bilateria, Protostomia and Deuterostomia, Lophotrochozoa and Ecdysozoa. In Cycliophora and some Digenea, it may have evolved twice in the same life cycle. The provisioning of developing young is associated with almost all known types of incubation chambers, with matrotrophic viviparity more widespread (20 phyla) than brooding (10 phyla). In nine phyla, both matrotrophic incubation types are present. Matrotrophy is expressed in five nutritive modes, of which histotrophy and placentotrophy are most prevalent. Oophagy, embryophagy and histophagy are rarer, plausibly evolving through heterochronous development of the embryonic mouthparts and digestive system. During gestation, matrotrophic modes can shift, intergrade, and be performed simultaneously. Invertebrate matrotrophic adaptations are less complex structurally than in chordates, but they are more diverse, being formed either by a parent, embryo, or both. In a broad and still preliminary sense, there are indications of trends or grades of evolutionarily increasing complexity of nutritive structures: formation of (i) local zones of enhanced nutritional transport (placental analogues), including specialized parent-offspring cell complexes and various appendages increasing the entire secreting and absorbing surfaces as well as the contact surface between embryo and parent, (ii) compartmentalization of the common incubatory space into more compact and 'isolated' chambers with presumably more effective nutritional relationships, and (iii) internal secretory ('milk') glands. Some placental analogues in onychophorans and arthropods mimic the simplest placental variants in vertebrates, comprising striking examples of convergent evolution acting at all levels-positional, structural and physiological.
Collapse
Affiliation(s)
- Andrew N Ostrovsky
- Department of Invertebrate Zoology, Faculty of Biology, Saint Petersburg State University, Universitetskaja nab. 7/9, 199034, Saint Petersburg, Russia
- Department of Palaeontology, Faculty of Earth Sciences, Geography and Astronomy, Geozentrum, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria
| | - Scott Lidgard
- Integrative Research Center, Field Museum of Natural History, 1400 S. Lake Shore Dr., Chicago, IL, 60605, U.S.A
| | - Dennis P Gordon
- National Institute of Water and Atmospheric Research, Private Bag 14901, Kilbirnie, Wellington, New Zealand
| | - Thomas Schwaha
- Department of Integrative Zoology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria
| | - Grigory Genikhovich
- Department for Molecular Evolution and Development, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria
| | - Alexander V Ereskovsky
- Department of Embryology, Faculty of Biology, Saint Petersburg State University, Universitetskaja nab. 7/9, 199034, Saint Petersburg, Russia
- Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale, Aix Marseille Université, CNRS, IRD, Avignon Université, Station marine d'Endoume, Chemin de la Batterie des Lions, 13007, Marseille, France
| |
Collapse
|
7
|
Kupfer A, Maxwell E, Reinhard S, Kuehnel S. The evolution of parental investment in caecilian amphibians: a comparative approach. Biol J Linn Soc Lond 2016. [DOI: 10.1111/bij.12805] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alexander Kupfer
- Staatliches Museum für Naturkunde Stuttgart; Rosenstein 1 Stuttgart 70191 Germany
- Institut für Biochemie und Biologie; Allgemeine Zoologie und Evolutionsgenomik; Universität Potsdam; Karl-Liebknecht-Strasse 24-25 Haus 26 Potsdam 14476 Germany
- Institut für Spezielle Zoologie und Evolutionsbiologie mit Phyletischem Museum; Friedrich Schiller-Universität Jena; Erbertstrasse 1 Jena 07743 Germany
| | - Erin Maxwell
- Staatliches Museum für Naturkunde Stuttgart; Rosenstein 1 Stuttgart 70191 Germany
| | - Sandy Reinhard
- Institut für Spezielle Zoologie und Evolutionsbiologie mit Phyletischem Museum; Friedrich Schiller-Universität Jena; Erbertstrasse 1 Jena 07743 Germany
- Naturhistorisches Museum; Thüringer Landesmuseum Heidecksburg; Schlossbezirk 1 Rudolstadt 07407 Germany
| | - Susanne Kuehnel
- Institut für Spezielle Zoologie und Evolutionsbiologie mit Phyletischem Museum; Friedrich Schiller-Universität Jena; Erbertstrasse 1 Jena 07743 Germany
| |
Collapse
|
8
|
Krause E, Caspers B. Long-term consequences of early nutritional conditions on the behaviour and growth of fire salamanders. AMPHIBIA-REPTILIA 2016. [DOI: 10.1163/15685381-0003033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Early developmental conditions can have a strong influence on the life history. Fire salamanders represent an interesting system due to their biphasic life cycle consisting of an aquatic larval stage and a subsequent terrestrial stage. The environment experienced as larvae affects growth, age at metamorphosis and behaviour. In particular, diet restrictions can cause developmental stress. However, the impact of such developmental stress on the growth and behaviour in a long-lived amphibian are not yet well studied. We manipulated the early diet of sibling pairs of fire salamander larvae. One sibling was raised under food-restriction and the other was raised under conditions of abundant food. We report long-term effects on growth and exploratory behaviour; exploratory behaviour was tested in two sessions, first as young juveniles and later as sub-adults. We found that food-restricted conditions during early development affected exploratory behaviour. Early deficits in body mass and body size were compensated later in life, by approximately 18 months of age. When morphological differences were compensated, the initial differences in exploratory behaviour also disappeared. Thus, compensation not only led to an alignment of body parameters but was also accompanied by an adjustment in exploratory behaviour. No cost of compensation was detected, but future research will need to verify whether the potential costs of compensation are negligible in slow-growing salamanders or whether they are shifted to later life stages. Our study provides novel insights into the life history of fire salamanders and reveals that early larval conditions have effects on individuals long after metamorphosis.
Collapse
Affiliation(s)
- E. Tobias Krause
- Friedrich-Loeffler-Institut, Institute of Animal Welfare and Husbandry, Doernbergstr. 25-27, 29223 Celle, Germany
- Department of Animal Behaviour, Bielefeld University, Morgenbreede 45, 33615 Bielefeld, Germany
| | - Barbara A. Caspers
- Department of Animal Behaviour, Bielefeld University, Morgenbreede 45, 33615 Bielefeld, Germany
| |
Collapse
|
9
|
Velo-Antón G, Santos X, Sanmartín-Villar I, Cordero-Rivera A, Buckley D. Intraspecific variation in clutch size and maternal investment in pueriparous and larviparous Salamandra salamandra females. Evol Ecol 2014. [DOI: 10.1007/s10682-014-9720-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
10
|
Wake MH. Fetal adaptations for viviparity in amphibians. J Morphol 2014; 276:941-60. [DOI: 10.1002/jmor.20271] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 02/03/2014] [Accepted: 02/09/2014] [Indexed: 11/12/2022]
Affiliation(s)
- Marvalee H. Wake
- Department of Integrative Biology and Museum of Vertebrate Zoology; University of California; Berkeley California 94720-3140
| |
Collapse
|
11
|
Bassar RD, Auer SK, Reznick DN. Why do placentas evolve? A test of the life-history facilitation hypothesis in two clades in the genusPoeciliopsisrepresenting two independent origins of placentas. Funct Ecol 2014. [DOI: 10.1111/1365-2435.12233] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ronald D. Bassar
- Department of Biology; University of California; Riverside California 92521 USA
| | - Sonya K. Auer
- Department of Biology; University of California; Riverside California 92521 USA
| | - David N. Reznick
- Department of Biology; University of California; Riverside California 92521 USA
| |
Collapse
|
12
|
Contribution of different Ca2+ channels to the acrosome reaction-mediated initiation of sperm motility in the newt Cynops pyrrhogaster. ZYGOTE 2013; 23:342-51. [DOI: 10.1017/s0967199413000609] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SummaryInitiation of sperm motility in urodeles, which is induced by a sperm motility-initiating substance (SMIS) in the sequestered granules on the surface of egg jelly, is mediated by the acrosome reaction (AR), which is triggered by an AR-inducing substance (ARIS) on a sheet-like structure. Details of the unique process of the interaction between egg jelly and sperm in these species is still unclear. The current study showed the fine structure of egg jelly in the newt Cynops pyrrhogaster, a urodele species, revealing that its outer surface was covered by a sheet-like structure of approximately 0.29 μm in thickness. Granules of approximately 2 μm in diameter with small particles of approximately 54 nm were attached to its surface and distributed inhomogeneously just beneath the sheet-like structure. Emission spectrometry revealed that the Ca2+ concentration was maintained at a high level compared with that of the blood plasma and the vas deferens fluid, suggesting that egg jelly is a reliable source of Ca2+ for the sperm–egg interaction. Blockers of the T-type voltage-dependent Ca2+ channel (VDCC), but not the L-type VDCC, inhibited both AR and initiation of sperm motility. Conversely, Ni+, which affects the α1 H subunit of T-type VDCC, only inhibited the initiation of sperm motility. These data suggest that, in response to ARIS and SMIS, sequential gating of distinct Ca2+ channels occurs in the AR, followed by the initiation of sperm motility on the surface of the egg jelly in C. pyrrhogaster at fertilization.
Collapse
|
13
|
Caspers BA, Krause ET, Hendrix R, Kopp M, Rupp O, Rosentreter K, Steinfartz S. The more the better - polyandry and genetic similarity are positively linked to reproductive success in a natural population of terrestrial salamanders (Salamandra salamandra). Mol Ecol 2013; 23:239-50. [PMID: 24168518 DOI: 10.1111/mec.12577] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 09/09/2013] [Accepted: 10/13/2013] [Indexed: 11/30/2022]
Abstract
Although classically thought to be rare, female polyandry is widespread and may entail significant fitness benefits. If females store sperm over extended periods of time, the consequences of polyandry will depend on the pattern of sperm storage, and some of the potential benefits of polyandry can only be realized if sperm from different males is mixed. Our study aimed to determine patterns and consequences of polyandry in an amphibian species, the fire salamander, under fully natural conditions. Fire salamanders are ideal study objects, because mating, fertilization and larval deposition are temporally decoupled, females store sperm for several months, and larvae are deposited in the order of fertilization. Based on 18 microsatellite loci, we conducted paternity analysis of 24 female-offspring arrays with, in total, over 600 larvae fertilized under complete natural conditions. More than one-third of females were polyandrous and up to four males were found as sires. Our data clearly show that sperm from multiple males is mixed in the female's spermatheca. Nevertheless, paternity is biased, and the most successful male sires on average 70% of the larvae, suggesting a 'topping off' mechanism with first-male precedence. Female reproductive success increased with the number of sires, most probably because multiple mating ensured high fertilization success. In contrast, offspring number was unaffected by female condition and genetic characteristics, but surprisingly, it increased with the degree of genetic relatedness between females and their sires. Sires of polyandrous females tended to be genetically similar to each other, indicating a role for active female choice.
Collapse
Affiliation(s)
- Barbara A Caspers
- Department of Animal Behaviour, Bielefeld University, Morgenbreede 45, 33615, Bielefeld, Germany
| | | | | | | | | | | | | |
Collapse
|
14
|
Reinhardt T, Steinfartz S, Paetzold A, Weitere M. Linking the evolution of habitat choice to ecosystem functioning: direct and indirect effects of pond-reproducing fire salamanders on aquatic-terrestrial subsidies. Oecologia 2013; 173:281-91. [PMID: 23358795 DOI: 10.1007/s00442-013-2592-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Accepted: 01/07/2013] [Indexed: 11/28/2022]
Abstract
Shifts in life history traits and in the behaviour of species can potentially alter ecosystem functioning. The reproduction of the central European fire salamander (Salamandra salamandra), which usually deposits its larvae in first-order streams, in small pool and pond-like habitats, is an example of a recent local adaptation in this species. Here we aimed to quantify the direct and indirect effects of the predatory larvae on the aquatic food webs in the ponds and on the flux of matter between the ponds and adjacent terrestrial habitats. Our estimates are based on biomass data of the present pond fauna as well as on the analysis of stomach content data, growth rates and population dynamics of the salamander larvae in pond habitats. By their deposition of larvae in early spring, female fire salamanders import between 0.07 and 2.86 g dry mass m(-2) larval biomass into the ponds. Due to high mortality rates in the larval phase and the relatively small size at metamorphosis of the pond-adapted salamanders compared to stream-adapted ones, the biomass export of the metamorphosed salamanders clearly falls below the initial biomass import. Catastrophic events such as high water temperatures and low oxygen levels may even occasionally result in mass mortalities of salamander larvae and thus in a net 100 % import of the salamander biomass into the pond food webs. Indirect effects further accelerate this net import of matter into the aquatic habitat, e.g. the feeding of salamanders on aquatic insect larvae with the emergence of terrestrial adults-thus preventing export-and on terrestrial organisms that fall on the water surface (supporting import). This study demonstrates that the adaptation of salamanders to pond reproduction can alter food web linkages across ecosystem boundaries by enhancing the flux of materials and energy from terrestrial (i.e. forest) to the aquatic (i.e. pond) habitat.
Collapse
Affiliation(s)
- Timm Reinhardt
- Department of River Ecology, Helmholz-Center for Environmental Research-UFZ, Magdeburg, Germany
| | | | | | | |
Collapse
|
15
|
Sperm motility initiation by egg jelly of the anuran, Discoglossus pictus may be mediated by sperm motility-initiating substance of the internally-fertilizing newt, Cynops pyrrhogaster. ZYGOTE 2012; 20:417-22. [DOI: 10.1017/s0967199412000226] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SummaryThe egg jelly of Discoglossus pictus contains sperm motility-activating activity, the molecular basis of which has not been studied. Discoglossus pictus sperm initiated motility immediately after immersion in egg-jelly extract, as well as after immersion in hyposmotic solution, which initiates sperm motility in the external fertilization of anuran amphibians. Sequential treatment of the D. pictus sperm with these two solutions revealed the predominant effect of hyposmolality in initiation of motility. The motility initiation induced by jelly extract was suppressed by a monoclonal antibody (mAb) that is specific for the 34 kDa sperm motility-initiating substance (SMIS) in the egg jelly of the newt, Cynops pyrrhogaster. Immunoblotting using the anti-SMIS mAb revealed several antigenic proteins that included major ones with sizes of 18- and 34-kDa in D. pictus jelly extract. Scanning electron microscopic observation revealed that granules of jelly matrix, in which SMIS localizes and which have a critical role in the internal fertilization of C. pyrrhogaster, were not observed near the surface of the D. pictus egg jelly. These results suggest that sperm motility-activating activity in egg jelly of D. pictus may be mediated by SMIS homologous proteins that act through a mechanism that is partially different from that of C. pyrrhogaster.
Collapse
|
16
|
Velo-Antón G, Zamudio KR, Cordero-Rivera A. Genetic drift and rapid evolution of viviparity in insular fire salamanders (Salamandra salamandra). Heredity (Edinb) 2012; 108:410-8. [PMID: 22086081 PMCID: PMC3313053 DOI: 10.1038/hdy.2011.91] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 09/02/2011] [Accepted: 09/08/2011] [Indexed: 11/09/2022] Open
Abstract
Continental islands offer an excellent opportunity to investigate adaptive processes and to time microevolutionary changes that precede macroevolutionary events. We performed a population genetic study of the fire salamander (Salamandra salamandra), a species that displays unique intraspecific diversity of reproductive strategies, to address the microevolutionary processes leading to phenotypic and genetic differentiation of island, coastal and interior populations. We used eight microsatellite markers to estimate genetic diversity, population structure and demographic parameters in viviparous insular populations and ovoviviparous coastal and interior populations. Our results show considerable genetic differentiation (F(ST) range: 0.06-0.27), and no clear signs of gene flow among populations, except between the large and admixed interior populations. We find no support for island colonization by rafting or intentional/accidental anthropogenic introductions, indicating that rising sea levels were responsible for isolation of the island populations approximately 9000 years ago. Our study provides evidence of rapid genetic differentiation between island and coastal populations, and rapid evolution of viviparity driven by climatic selective pressures on island populations, geographic isolation with genetic drift, or a combination of these factors. Studies of these viviparous island populations in early stages of divergence help us better understand the microevolutionary processes involved in rapid phenotypic shifts.
Collapse
Affiliation(s)
- G Velo-Antón
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
- Grupo de Ecoloxía Evolutiva e da Conservación, Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, EUET Forestal, Pontevedra, Spain
| | - K R Zamudio
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
| | - A Cordero-Rivera
- Grupo de Ecoloxía Evolutiva e da Conservación, Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, EUET Forestal, Pontevedra, Spain
| |
Collapse
|
17
|
Krause ET, Steinfartz S, Caspers BA. Poor Nutritional Conditions During the Early Larval Stage Reduce Risk-Taking Activities of Fire Salamander Larvae (Salamandra salamandra). Ethology 2011. [DOI: 10.1111/j.1439-0310.2011.01886.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
18
|
González-León E, Ramírez-Pinilla MP. Cloacal morphology in Bolitoglossa nicefori (Caudata: Plethodontidae): Variation during the reproductive cycle. Anat Rec (Hoboken) 2011; 294:349-62. [PMID: 21235010 DOI: 10.1002/ar.21306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 09/07/2010] [Indexed: 11/10/2022]
Abstract
Male and female plethodontid salamanders have specialized cloacal glands associated with the reproductive activity. The reproductive cycle in Bolitoglossa nicefori is characterized by males that are potentially reproductive throughout the year, and females that are reproductive only for a few months. To determine whether morphological and histochemical variation occur in cloacal structures related to reproductive activity, the cloacal region of male and female specimens of B. nicefori was studied in different stages of their annual reproductive cycle using light microscopy and compared with features reported in other plethodontid salamanders. The main anatomy and histology of the male and female cloacal regions of B. nicefori are similar to those of other salamanders; however, in comparison to other Bolitoglossa previously studied, B. nicefori has a relatively larger cloacal tube and a tubular rather than acinar spermatheca. As a common trait, the spermatheca has a common tube that diverges into two tubules, before branching into spermathecal tubules, horizontally arranged on frontal planes. The secretions of the spermathecal glands differed between reproductive and nonreproductive adult females. This secretory product consists of prevailing neutral carbohydrates that were related to the increase in ovarian follicular size during the breeding season. Sperm was found only in the spermatheca of reproductive periovulatory females, suggesting that the reproductive cycle involves a no long-term storage of sperm. Although males can produce sperm throughout the year, spermatophores, namely specialized structures involved in sperm transport, were found in their cloaca only during the breeding season. In these males, some of the cloaca-associated glands were seen to undergo change their secretory activity and their secretory products were related to spermatophore formation.
Collapse
Affiliation(s)
- Ezequiel González-León
- Laboratorio de Biología Reproductiva de Vertebrados, Escuela de Biología, Universidad Industrial de Santander, Bucaramanga, Colombia
| | | |
Collapse
|
19
|
Ohta M, Kubo H, Nakauchi Y, Watanabe A. Sperm Motility-Initiating Activity in the Egg Jelly of the Externally-Fertilizing Urodele Amphibian,Hynobius lichenatus. Zoolog Sci 2010; 27:875-9. [DOI: 10.2108/zsj.27.875] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
20
|
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
| |
Collapse
|
21
|
Menkhorst E, Selwood L. Vertebrate Extracellular Preovulatory and Postovulatory Egg Coats. Biol Reprod 2008; 79:790-7. [DOI: 10.1095/biolreprod.108.068551] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
|
22
|
Steinfartz S, Weitere M, Tautz D. Tracing the first step to speciation: ecological and genetic differentiation of a salamander population in a small forest. Mol Ecol 2007; 16:4550-61. [PMID: 17877714 DOI: 10.1111/j.1365-294x.2007.03490.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mechanisms and processes of ecologically driven adaptive speciation are best studied in natural situations where the splitting process is still occurring, i.e. before complete reproductive isolation is achieved. Here, we present a case of an early stage of adaptive differentiation under sympatric conditions in the fire salamander, Salamandra salamandra, that allows inferring the underlying processes for the split. Larvae of S. salamandra normally mature in small streams until metamorphosis, but in an old, continuous forest area near Bonn (the Kottenforst), we found salamander larvae not only in small streams but also in shallow ponds, which are ecologically very different from small streams. Common-environment experiments with larvae from both habitat types reveal specific adaptations to these different ecological conditions. Mitochondrial and microsatellite analyses show that the two ecologically differentiated groups also show signs of genetic differentiation. A parallel analysis of animals from a neighbouring much larger forest area (the Eifel), in which larvae mature only in streams, shows no signs of genetic differentiation, indicating that gene flow between ecologically similar types can occur over large distances. Hence, geographical factors cannot explain the differential larval habitat adaptations in the Kottenforst, in particular since adult life and mating of S. salamandra is strictly terrestrial and not associated with larval habitats. We propose therefore that the evolution of these adaptations was coupled with the evolution of cues for assortative mating which would be in line with models of sympatric speciation that suggest a co-evolution of habitat adaptations and associated mating signals.
Collapse
Affiliation(s)
- Sebastian Steinfartz
- University of Cologne, Institute of Genetics, Zülpicherstrasse 47, D-50674 Cologne, Germany.
| | | | | |
Collapse
|
23
|
Jantra S, Bigliardi E, Brizzi R, Ietta F, Bechi N, Paulesu L. Interleukin 1 in Oviductal Tissues of Viviparous, Oviparous, and Ovuliparous Species of Amphibians1. Biol Reprod 2007; 76:1009-15. [PMID: 17314310 DOI: 10.1095/biolreprod.107.060095] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
In previous reports, we have shown that interleukin 1 (IL1), a cytokine associated with implantation in mice, is also expressed in reproductive tissues of viviparous squamate reptiles and cartilaginous fishes. In the present study, we investigated the expression of IL1B and its functional membrane receptor type I (IL1R1) in amphibians, a class of vertebrates that is characterized by different reproductive modes, including internal and external fertilization. In particular, we investigated the oviductal tissues of the aplacental viviparous Salamandra lanzai, the oviparous Triturus carnifex, and the ovuliparous Bufo bufo. In immunohistochemistry with anti-human IL1B and IL1R1 polyclonal antibodies we found that in S. lanzai, most cells in the uterine mucosa were immunoreactive for IL1B and IL1R1. In T. carnifex, IL1B and IL1R1 were present in ciliated luminal cells, and there was evidence of IL1B in glandular cells. In B. bufo, the expression of IL1B and IL1R1 was limited to the apical cytoplasm of the ciliated oviductal cells. Western blot analysis showed that a putative mature form of IL1B, similar to that seen in mammals, was present in the oviductal tissues of S. lanzai, whereas different forms, which probably correspond to an inactive pro-IL1B protein, were found in T. carnifex and B. bufo. A band that corresponded to the predicted 80-kDa human IL1R1 was found in S. lanzai and T. carnifex. Although the present study shows that IL1B and IL1R1 expression occurs in all reproductive modes, the differential expression patterns noted between ovuliparity and oviparity and viviparity may reflect the different roles of IL1 in the various reproductive modes.
Collapse
Affiliation(s)
- Silke Jantra
- Department of Physiology, Division of Immunoendocrinology and Reproductive Physiology and Department of Evolutionary Biology, University of Siena, Via Aldo Moro, 53100 Siena, Italy
| | | | | | | | | | | |
Collapse
|
24
|
Buckley D, Alcobendas M, García-París M, Wake MH. Heterochrony, cannibalism, and the evolution of viviparity in Salamandra salamandra. Evol Dev 2007; 9:105-15. [PMID: 17227370 DOI: 10.1111/j.1525-142x.2006.00141.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The way in which novelties that lead to macroevolutionary events originate is a major question in evolutionary biology, and one that can be addressed using the fire salamander (Salamandra salamandra) as a model system. It is exceptional among amphibians in displaying intraspecific diversity of reproductive strategies. In S. salamandra, two distinct modes of reproduction co-occur: the common mode, ovoviviparity (females giving birth to many small larvae), and a phylogenetically derived reproductive strategy, viviparity (females producing only a few large, fully metamorphosed juveniles, which are nourished maternally). We examine the relationship between heterochronic modifications of the ontogeny and the evolution of the new reproductive mode in the fire salamander. The in vitro development of embryos of ovoviviparous and viviparous salamanders from fertilization to metamorphosis is compared, highlighting the key events that distinguish the two modes of reproduction. We identify the heterochronic events that, together with the intrauterine cannibalistic behavior, characterize the derived viviparous reproductive strategy. The ways in which evolutionary novelties can arise by modification of developmental programs can be studied in S. salamandra. Moreover, the variation in reproductive modes and the associated variation of sequences of development occur in neighboring, conspecific populations. Thus, S. salamandra is a unique biological system in which evolutionary developmental research questions can be addressed at the level of populations.
Collapse
Affiliation(s)
- David Buckley
- Museo Nacional de Ciencias Naturales, José Gutiérrez Abascal 2, 28006 Madrid, Spain.
| | | | | | | |
Collapse
|
25
|
Takahashi S, Nakazawa H, Watanabe A, Onitake K. The outermost layer of egg-jelly is crucial to successful fertilization in the newt,Cynops pyrrhogaster. ACTA ACUST UNITED AC 2006; 305:1010-7. [PMID: 17068800 DOI: 10.1002/jez.a.295] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The significance of egg-jelly layers in internal fertilization was evaluated in the newt, Cynops pyrrhogaster. In this species, six egg-jelly layers, J1, J2, J3, J4, J5 and the outermost J6 layers, are accumulated on the surface of the fertilizable eggs in pars convoluta of the oviduct. When a large number of sperm (about 6 x 10(5)) were placed on eggs having different numbers of jelly layers, all the eggs were fully fertilized, although many of the eggs developed abnormally. Upon insemination using about 600 sperm, only eggs with the full set of jelly layers were fertilized at a high rate with normal development. Since around 300 (the range of 48-1,192) sperm were observed on and in the egg-jelly in naturally spawned eggs, we conclude that the J6 layer must be present on the outermost surface of the egg-jelly for successful internal fertilization of the newt. Previous studies have suggested that the J6 layer is a prerequisite for the initiation of sperm motility and the acrosome reaction. In the present study, the fertilization rate decreased in eggs with a full set of jelly layers when inseminated using acrosome-reacted and motile sperm. However, the fertilization rate was high when motile sperm with intact acrosome was used. These results suggest that induction of the sperm acrosome reaction in the J6 layer is an important step in the internal fertilization of the newt.
Collapse
Affiliation(s)
- Shigekazu Takahashi
- Department of Biology, Faculty of Science, Yamagata University, Yamagata 990-8560, Japan
| | | | | | | |
Collapse
|
26
|
Steinfartz S, Stemshorn K, Kuesters D, Tautz D. Patterns of multiple paternity within and between annual reproduction cycles of the fire salamander (Salamandra salamandra) under natural conditions. J Zool (1987) 2005. [DOI: 10.1111/j.1469-7998.2005.00001.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
27
|
Ehmcke J, Clemen G, Greven H. Complex secretory products in the oviduct of the plethodontid salamander Bolitoglossa dofleini (Amphibia, Urodela). Tissue Cell 2005; 37:203-11. [PMID: 15936357 DOI: 10.1016/j.tice.2005.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2004] [Revised: 01/06/2005] [Accepted: 01/12/2005] [Indexed: 11/23/2022]
Abstract
The ultrastructure of the secretory granules in the cells of the subdivisions of the oviduct in the neotropical plethodontid salamander Bolitoglossa dofleini was studied by transmission electron microscopy. In addition, we applied the cationic dye Cuprolinic Blue (CB) at different electrolyte concentrations to demonstrate proteoglycans, and the pyrogallol red-copper (PR-C) method to stain proteins at the ultrastructural level. The entire oviduct is lined by a simple epithelium that contains ciliated and microvillous cells in the first subdivision, the aglandular pars recta; microvillous cells show a moderate secretory activity. The following pars convoluta is differentiated into five glandular subdivisions and the aglandular "uterine portion". Especially in the glandular parts, the epithelium is arranged in longitudinal folds. At their crests ciliated and microvillous cells similar to those in the pars recta occur. Gland cells are crowded with secretory granules that differ in their structural complexity (with and without electron-dense spheres or masses; elaborated, homogeneous or granular matrix; spherical; distorted) along the various subdivisions. Further, as suggested by the CB-technique, the cranial subdivisions contain large amounts of sulphated proteoglycans that decrease in the caudal direction. Carboxylated proteglycans appear to be present in all subdivisions examined. Electron-dense spheres of secretory granules are largely free of CB-precipitates, but stain more or less intensely with PR-C. The ultrastructure of the pars recta, and especially the "uterine portion" indicates transporting capability. The epithelial cells of the "uterus" have coated pits and a considerable amount of lysosome-like bodies.
Collapse
Affiliation(s)
- J Ehmcke
- Institut für Spezielle Zoologie und Entwicklungsbiologie der Universität Münster, Hüfferstr. 1, D-48149 Münster, Germany
| | | | | |
Collapse
|
28
|
Allen ME, Ullrey DE. Relationships among nutrition and reproduction and relevance for wild animals. Zoo Biol 2004. [DOI: 10.1002/zoo.20029] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
29
|
Watanabe T, Itoh T, Watanabe A, Onitake K. Characteristics of sperm motility induced on the egg-jelly in the internal fertilization of the newt, Cynops pyrrhogaster. Zoolog Sci 2003; 20:345-52. [PMID: 12692394 DOI: 10.2108/zsj.20.345] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Most urodeles undergo internal fertilization and sperm are directly inseminated onto the surface of egg-jelly. Feature of sperm motility induced on the egg-jelly was examined in the newt, Cynops pyrrhogaster. When sperm were directly inseminated onto an egg-jelly, sperm motility was immediately induced on its surface. The egg-jelly of C. pyrrhogaster was composed of six sublayers that were added by turns in oviduct. When the eggs with various sets of the sublayers were obtained and sperm were inseminated onto the egg-jelly, the immediate activity for the initiation of sperm motility was observed only on the outermost sublayer. Similarly, the immediate initiation of sperm motility was induced in the sperm suspended in the extract of the egg-jelly (JE). The initiation of sperm motility was affected by the external pH, and the motility was activated in the moving sperm. A K(+)-channel antagonist, charybdotoxin (CTX), or a Ca(2+)-channel antagonist, gallopamil inhibited the initiation of sperm motility in a dose dependent manner. These results demonstrated the feature of the mechanism regulating sperm motility under stable surroundings in the internal fertilization of amphibians.
Collapse
Affiliation(s)
- Toshihiko Watanabe
- Department of Biology, Faculty of Science, Yamagata University, Yamagata 990-8560, Japan
| | | | | | | |
Collapse
|
30
|
Watanabe A, Onitake K. The urodele egg-coat as the apparatus adapted for the internal fertilization. Zoolog Sci 2002; 19:1341-7. [PMID: 12520093 DOI: 10.2108/zsj.19.1341] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Fertilization is a significant event for reproducing offspring. It is achieved under a species-specific environment, which influences the conditions to assure the successful fertilization in some cases. Several studies about the basic mechanism of fertilization suggest that the fertilization mechanism is modified among species to be suited for the fertilization environment. In amphibians, many anurans undergo external fertilization while most urodeles do internal fertilization. An amphibian egg is surrounded by egg-coats, which are composed of vitelline envelope and layered egg-jelly. They are significant as fields for the sperm-egg interaction at fertilization. The fertilization processes that take place in the egg-coats are supposed to be easily influenced by the fertilization environment, because they, especially egg-jelly, are exposed to the surroundings at fertilization. In the present article, we describe the fertilization system equipped in newt egg-coats. Newt sperm are stored in spermatheca that exists in cloaca of a female and directly inseminated on the surface of egg-jelly. Sperm motility and acrosome reaction are induced in the outermost portion of the egg-jelly. Motion of the moving sperm becomes vigorous in the egg-jelly and sperm are guided to vitelline envelope by the aid of egg-jelly structure. Most of the sperm passing through the egg-jelly, as the result, has been induced acrosome reaction and those sperm can bind to the vitelline envelope to contribute to the successful fertilization. This fertilization system has a distinct feature from the known system in species undergoing external fertilization. The feature of the system in the newt egg-jelly is discussed with the view to achieving the successful fertilization in the internal environment.
Collapse
Affiliation(s)
- Akihiko Watanabe
- Department of Biology, Faculty of Science, Yamagata University, Japan
| | | |
Collapse
|
31
|
Itoh T, Kamimura S, Watanabe A, Onitake K. Egg-jelly structure promotes efficiency of internal fertilization in the newt, Cynops pyrrhogaster. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 2002; 292:314-22. [PMID: 11857465 DOI: 10.1002/jez.10019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Egg-jelly is composed of a network of fibrous components and contains substances regulating the sperm-egg interaction. Many studies on the latter have been conducted, whereas the role of the egg-jelly structure in fertilization has not yet been fully assessed. In this study, we examined the fertilization efficiency in the presence and absence of the structure around the egg of the newt, Cynops pyrrhogaster, using a gelatin gel system. Although de-jellied eggs of C. pyrrhogaster can be fertilized with an adequate number of sperm, the fertilization rate was dramatically increased through the use of the gelatin gel. Sperm showed forward motility with straight morphology in the gel, whereas they swam in circles in solution. This result indicates that the gel structure is significant for sperm guidance to the egg surface, and its presence raises the fertilization efficiency in C. pyrrhogaster. When sperm were entangled in the gel structure, they were immediately folded and never showed any forward motility. Sperm with zigzag morphology were observed in the gelatin gel as well as in the egg-jelly, indicating the elimination of sperm by the gel structure. The effect of sperm elimination on successful fertilization was estimated using gelatin gels of different thickness. Though the variation did not affect the fertilization rate, the rate of normal development gradually increased in the thicker gels. This result indicates that sperm elimination in egg-jelly can function in the fertilization system. The roles of sperm guidance and sperm elimination under the physiological condition of internal fertilization of the newt are discussed.
Collapse
Affiliation(s)
- Tokuko Itoh
- Department of Biology, Faculty of Science, Yamagata University, Yamagata, 990-8560 Japan
| | | | | | | |
Collapse
|
32
|
Deban SM, O'Reilly JC, Nishikawa KC. The Evolution of the Motor Control of Feeding in Amphibians. ACTA ACUST UNITED AC 2001. [DOI: 10.1093/icb/41.6.1280] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
33
|
|
34
|
Okimura M, Watanabe A, Onitake K. Organization of Carbohydrate Components in the Egg-Jelly Layers of the Newt, Cynops pyrrhogaster. Zoolog Sci 2001. [DOI: 10.2108/zsj.18.909] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|