Ultrastructure of the mature spermatozoa of caecilians (Amphibia: Gymnophiona)

Scheltinga, D. M.; Wilkinson, Mark; Jamieson, B. G. M.; Oommen, Oommen V.

doi:10.1002/jmor.10139

Cited by 14 publications

(19 citation statements)

References 24 publications

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“…(E) Distribution of spermatids containing either a centriolar midpiece or an axonemal midpiece across animal phylogeny. Based on (Afzelius, 1955; Al-Dokhi et al, 2007; Dallai et al, 1995; Dallai et al, 2010; Hess et al, 1991; Iomini and Justine, 1997; Lipke et al, 2009; Mattei, 1988; Medina, 1994; Mita and Nakamura, 1992; Reger and Cooper, 1968; Reunov and Klepal, 2003; Sato et al, 1967; Scheltinga et al, 2003; Silveira and Porter, 1964; Smita et al, 2004; Vignoli et al, 2008)…”

Section: Figurementioning

confidence: 99%

Transition Zone Migration: A Mechanism for Cytoplasmic Ciliogenesis and Postaxonemal Centriole Elongation

Avidor‐Reiss

Basiri

2017

Cold Spring Harb Perspect Biol

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The cilium is an elongated and continuous structure that spans two major subcellular domains. The cytoplasmic domain contains a short centriole, which serves to nucleate the main projection of the cilium. This projection, known as the axoneme, remains separated from the cytoplasm by a specialized gatekeeping complex within a ciliary subdomain called the transition zone. In this way, the axoneme is compartmentalized. Intriguingly, however, this general principle of cilium biology is altered in the sperm cells of many animals, which instead contain a cytoplasmic axoneme domain. Here, we discuss the hypothesis that the formation of specialized sperm giant centrioles and cytoplasmic cilia is mediated by the migration of the transition zone from its typical location as part of a structure known as the annulus, and examine the intrinsic properties of the transition zone that may facilitate its migratory behavior.

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Section: Figurementioning

confidence: 99%

Transition Zone Migration: A Mechanism for Cytoplasmic Ciliogenesis and Postaxonemal Centriole Elongation

Avidor‐Reiss

Basiri

2017

Cold Spring Harb Perspect Biol

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“…The study of sperm structure and development is providing new data relevant for phylogenetic inference within higher categories (Dallai et al 2003a(Dallai et al , 2003bScheltinga et al 2003;Marotta & Ruhberb 2004;Meisner et al 2005). However, data on spider sperm ultrastructure and development continue to be fragmentary in most groups (Michalik & Huber 2006), and most of the morphological studies are focused on spermiogenetic events (Alberti & Coyle 1991;Klann et al 2005;Costa-Ayub & Faraco 2007).…”

Section: Introductionmentioning

confidence: 99%

Fine structural reconstruction on the testicular cyst of the furrow orb weaver,Larinioides cornutusby 3D volume rendering

Kim

Seo

Kim

et al. 2016

Animal Cells and Systems

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Morphological study on spermatids and spermatozoa have long been performed regarding various changes of cell organelles during spermiogenesis as a potential phylogenetic inference. Based on the fact that the number of germ cells per cyst increases according to a geometric series, knowing the exact number of germ cells in a certain stage may lead to the total number of sperms produced per cyst. In spiders, however, the entire process takes place in a cyst represented by a spermatogonium, producing sperms in spherical shape. It is very difficult to count the exact number of germ cells produced per cyst through a 2D image analysis. Therefore, we applied a 3D image of testicular cyst of an orb-weaving spider to visualize the exact number of germ cells produced from a cyst. In this study, 2D images obtained from serially sectioned micrographs were scanned precisely and reconstructed using a 3D-rendering technique. Finally, this research reveals that the exact number of spermatozoa produced each cyst in Larinioides cornutus appeared to be 128 (2 7 ), which indicates that a single spermatogonium undergoes five mitotic divisions and two maturing divisions (meiosis) to produce final spermatozoa. ARTICLE HISTORY

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“…The ultrastructural components of the amphibian sperm cell have been well described (see Swan et al 1980;Selmi et al 1997;Scheltinga et al 2003). The majority of studies have focused on spermiogenesis or cytological descriptions of spermatozoa but the predominant interest has been on the taxonomic classification of the extant amphibian orders; for example, recent studies (e.g.…”

Section: The Amphibian Sperm Cellmentioning

confidence: 99%

“…The nuclear fossa is surrounded peripherally by abundant mitochondria responsible for converting oxygen and nutrients into adenosine triphosphate (ATP) required for the metabolic processes of the spermatozoon, as well as providing energy for motility (Selmi et al 1997;Costa et al 2004). The mitochondria are characterised by concentric cristae that typically form a spiral aggregation or mitochondrial collar around the base of the axoneme that originates from the distal centriole (Seshachar 1943;Selmi et al 1997;Scheltinga et al 2003; see Figure 1.1).…”

Section: Nucleusmentioning

confidence: 99%

“…The axoneme is formed from the distal centriole during spermiogenesis and the two structures are continuous in the mature spermatozoa. The axoneme contains the microtubule arrangement typical of vertebrates with a central pair of microtubules surrounded by a circular array of nine outer pairs (Duellman and Trueb 1986;Scheltinga et al 2003;Costa et al 2004). Notable differences occur in the tail structure of anurans (see Figure 1.1).…”

Section: Sperm Tail and Undulating Membranementioning

confidence: 99%

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Amphibian sperm DNA fragmentation

Pollock¹

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There are extremely limited studies that have investigated DNA fragmentation in amphibians and even less information exists pertaining to DNA fragmentation in the spermatozoa.A DNA fragmentation assay applied and validated for amphibian spermatozoa would not only provide the first evidence of this phenomenon in a new major taxon, but also prove a valuable tool for developing improvements in ART used in the captive propagation of threatened and endangered species. Consequently, the fundamental aim of this project was the development and validation of the sperm chromatin dispersion (SCD) test for amphibian spermatozoa with the purpose of investigating the dynamic behaviour of amphibian sperm DNA in response to cryopreservation.The SCD test was first applied to African clawed frog (Xenopus laevis) as an amphibian sperm model using a species-specific modified lysing solution for protein depletion. Sperm DNA fragmentation (SDF) was assessed immediately following activation of sperm motility (T0) and again after one hour and 24 hours of incubation in order to produce a range of spermatozoa with differing levels of DNA damage. The SCD procedure resulted in the production of three nuclear morphotypes; amphibian sperm morphotype 1 (ASM-1) and ASM-2 showed no evidence of DNA damage, whereas ASM-3 spermatozoa were highly fragmented with large halos of dispersed DNA fragments and a reduced nuclear core. Levels of SDF revealed by the SCD test were highly correlated with results produced using in situ nick hybridisation with DNA-specific molecular probes (ISNT) and the double comet assay (r = 0.9613). The alkaline step of the double-comet assay revealed the extensive presence of structural single-stranded DNA breaks (SSB) and provided grounds for the suggestion that alkali labile sites (ALS) are a constitutive feature of African clawed frog sperm chromatin.SDF is a dynamic process and has been shown to increase with incubation at room temperature as well as following cryopreservation. However, the mechanisms of DNA cryoinjury and the resulting effect on the potential reproductive output of ART remain open to interpretation.Consequently, dynamic changes to the basal level of DNA fragmentation were examined in fresh African clawed frog spermatozoa in comparison with the post-thaw integrity of cryopreserved (-80 °C) and frozen (-20 °C) sperm DNA. SDF was examined initially at T0 and over incubation of up to 60 minutes. The difference in SDF was only marginal for fresh, frozen (-20 °C) and cryopreserved (-80 °C) spermatozoa examined at the onset of the experiment immediately upon thawing, however, a significant increase (p = 0.004) in SDF, albeit of a low magnitude, was observed in activated ii cryopreserved (-80 °C) spermatozoa following incubation. Although African clawed frog spermatozoa appeared to be highly resistant to cryopreservation-induced DNA damage, cryopreserved-thawed spermatozoa yielded a significantly lower (p = 0.0065) fertilisation rate than fresh spermatozoa.In order to provide further insight into cryo...

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Ultrastructure of the mature spermatozoa of caecilians (Amphibia: Gymnophiona)

Cited by 14 publications

References 24 publications

Transition Zone Migration: A Mechanism for Cytoplasmic Ciliogenesis and Postaxonemal Centriole Elongation

Transition Zone Migration: A Mechanism for Cytoplasmic Ciliogenesis and Postaxonemal Centriole Elongation

Fine structural reconstruction on the testicular cyst of the furrow orb weaver,Larinioides cornutusby 3D volume rendering

Amphibian sperm DNA fragmentation

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