The ultrastructure of the mullet Mugil curema Valenciennes (Teleostei, Mugilidae) spermatozoa

Abstract

The structure of the spermatozoon of Mugil curema Valenciennes, 1836 was studied using scanning and transmission electron microscopy. The spermatic head is rounded and formed by the nucleus containing granular chromatin, firmly packed resulting in a mass extremely electron dense. The acrossome is absent. The midpiece is characterized by the presence of two centrioles, a plasmatic canal, very few vesicles, and several mitochondria (9-10) with aproximately 0.50µm in diameter. The head and the midpiece are aproximately 1.56µm in diameter. The flagellum conforms to the 9 + 0 flagellar pattern near the transition region in its midpiece and is 9 + 2 from there on up to the distal region of the axoneme. The electron density in the A tubules 1, 2, 5 and 6 shows the asymetry of this spermatozoa. Its spermatic cell differs ultrastructuraly from those of other Mugilidae species mainly because it has the highest number of mitochondria

Ultrastructure of grey mullet (Mugil cephalus, Linnaeus, 1758) spermatozoa as revealed from light, scanning and transmission electron microscopy

“…Chromatin granules of the nucleus form an electron‐dense homogeneous compact mass, probably attributed to the nuclear material that was not perfectly dehydrated during spermatogenesis (Guan et al., ). The kidney‐shaped nucleus in M. cephalus is similar to M. curema and other mugilidae (Eiras‐Stofella et al., ). The diameter of M. cephalus spermatozoa nucleus (1.67 ± 0.25 μ m) is close to that of L. aurata (1.5 μ m) and M. curema (1.0 μ m) (Eiras‐Stofella et al., ).…”

“…The diameter of M. cephalus spermatozoa nucleus (1.67 ± 0.25 μ m) is close to that of L. aurata (1.5 μ m) and M. curema (1.0 μ m) (Eiras‐Stofella et al., ). In M. cephalus, the proximal centriole is in an oblique position to the distal centriole, which is a common feature in the mugilidae family (Eiras‐Stofella et al., ).…”

“…The length and width of a M. cephalus spermatozoa head are 1.80 ± 0.35 and 0.91 ± 0.30 μ m, respectively, which are close to that of other mugilidae species viz. M. liza and M. planatus, measuring 1.50 μ m (Eiras‐Stofella and Gremski, ), but smaller than Liza dumerii , which has a spermatozoa head diameter of 2.4 μ m (Van der Horst and Cross, ). Chromatin granules of the nucleus form an electron‐dense homogeneous compact mass, probably attributed to the nuclear material that was not perfectly dehydrated during spermatogenesis (Guan et al., ).…”

Ultrastructure of Thunnus thynnus and Euthynnus allettevatus spermatozoa

“…The perciform-type spermatozoon was originally described as possessing intratubular differentiations (ITDs) in the A microtubules of doublets 1, 2, 5 and 6 (Mattei et al, 1979;Jamieson, 1991;Mattei, 1991). ITDs have been clearly identified in many teleostean species (Mattei et al, 1979;Afzelius, 1981;Mattei, 1991;Eiras-Stofella et al, 1993), but appear to be absent in perciform-type spermatozoa of other teleosts belonging to different families (Mattei, 1991;Gwo et al, 1994;Lahnsteiner et al, 1994), including T. thynnus, E. alletteratus (present study) and two other species of the family Scombridae, S. japonicus and S. australasicus (Hara & Okiyama, 1998). Therefore, the presence or absence of ITDs does not appear to be a key feature in the characterization of the perciform-type sperm, though it might well define evolutionary affinities within the Perciformes.…”

Surface ultrastructure of the gills of the mulletsMugil curema, M. liza andM. platanus (Mugilidae, Pisces)

“…Taxonomic status of various species of the genus Mugil is quite controversial (Schultz, 1949;Thomson, 1963;Braga, 1978;'83;Menezes and Figueiredo, 1985;Hochberg et al, 1987;Godinho et al, 1988;Eiras-Stofella and Gremski, 1991;Eiras-Stofella et al, 1993;Fonseca Neto, 1996). Based on our studies of gill morphology, it seems possible that M. liza and M. platanus are two different populations of the same species.…”