SOME OBSERVATIONS ON SPERM DIMORPHISM

1929 ◽  
Vol 57 (5) ◽  
pp. 267-271 ◽  
Author(s):  
GERARD L. MOENCH ◽  
HELEN HOLT
Keyword(s):  
Sperm Dimorphism

Ultrastructural evidence of sperm dimorphism in Deladenus sp. (Tylenchomorpha: Sphaerularioidea: Allantonematidae)

Nematology ◽  
2007 ◽  
Vol 9 (3) ◽  
pp. 397-404 ◽  
Author(s):  
Hajime Kosaka ◽  
Manabu Kusunoki ◽  
Vladimir Yushin
Keyword(s):  
Electron Microscope ◽  
Parasitic Nematode ◽  
Spermatogenic Cells ◽  
Ultrastructural Evidence ◽  
Transmission Electron ◽  
Parallel Fibres ◽  
Sperm Dimorphism ◽  
Whole Life Cycle ◽  
First Time ◽  
Spherical Vesicles

AbstractThe dimorphic spermatozoa of the insect-parasitic nematode Deladenus sp. (Tylenchomorpha: Sphaerularioidea: Allantonematidae) were studied for the first time with a transmission electron microscope (TEM). The immature spermatozoa from the testis of mycetophagous males are 10-12 μm diam. and 4-5 μm long unpolarised cells with a centrally located nucleus without a nuclear envelope. The cytoplasm contains mitochondria and specific components, membranous organelles (MO) and fibrous bodies (FB). The MO are spherical vesicles with an internal system of finger-like invaginations of the membrane; the spindle-shaped FB consist of tightly packed parallel fibres. Spermatozoa from the uteri of infective females of Deladenus sp. are vastly different in size being tiny cells ca 2 μm diam. with a spherical or oval nucleus. Each cell contains several mitochondria and MO. Although each individual of Deladenus sp. contains only monomorphic spermatozoa, sperm dimorphism was revealed after analysis of the whole life cycle. Despite a difference in size the cytological characters of both types of spermatozoa conform to the typical rhabditid pattern. The presence of both MO and FB in sphaerularioidid spermatozoa differentiates the superfamily Sphaerularioidea from Tylenchoidea whose representatives lack MO in the spermatogenic cells.

Sperm dimorphism in Chilopoda: comparison of Scolopendromorpha and Geophilomorpha

1999 ◽  
Vol 35 (1) ◽  
pp. 45-53 ◽  
Author(s):  
MARCELLA CARCUPINO ◽  
ANNALISA BALDACCI ◽  
ANNA MARIA FAUSTO ◽  
GIUSEPPE SCAPIGLIATI ◽  
MASSIMO MAZZINI
Keyword(s):  
Sperm Dimorphism

Sperm dimorphism and spermatozeugmata in the commensal bivalve Pseudopythina macrophthalmensis (Galeommatoidea, Kelliidae)

Zoomorphology ◽  
2001 ◽  
Vol 120 (3) ◽  
pp. 177-189 ◽  
Author(s):  
Å. Jespersen ◽  
Takeharu Kosuge ◽  
Jørgen Lützen
Keyword(s):  
Sperm Dimorphism

Sperm dimorphism in Nicotiana tabacum L.

2001 ◽  
Vol 14 (1-2) ◽  
pp. 123-125 ◽  
Author(s):  
Hui Qiao Tian ◽  
Zhaojie Zhang ◽  
S. D. Russell
Keyword(s):  
Nicotiana Tabacum ◽  
Nicotiana Tabacum L ◽  
Sperm Dimorphism

Riders on the sperm: sperm dimorphism and spermatozeugmata in nematodes from the genus Steinernema (Rhabditida: Steinernematidae)

Nematology ◽  
2007 ◽  
Vol 9 (1) ◽  
pp. 61-75 ◽  
Author(s):  
Sergei Spiridonov ◽  
Mutsuhiro Yoshida ◽  
Vladimir Yushin
Keyword(s):  
Gap Junctions ◽  
Nuclear Envelope ◽  
Ultrastructural Study ◽  
Entomopathogenic Nematodes ◽  
Size Difference ◽  
Male Gametes ◽  
Motile Cells ◽  
Basic Set ◽  
Sperm Dimorphism ◽  
Mature Spermatozoa

AbstractA comparative ultrastructural study of the male gametes in entomopathogenic nematodes of the genus Steinernema (Rhabditida: Steinernematidae) is based on two species producing monomorphic (S. feltiae) and dimorphic (S. tami) spermatozoa. The spermatozoa of both species are basically the same as in many other Rhabditida. Immature spermatozoa from the testis are unpolarised cells containing a nucleus without a nuclear envelope, mitochondria and membranous organelles (MO), a unique component of the nematode spermatozoa. Mature spermatozoa have a nucleus, mitochondria and emptied MO, each attached to a sperm plasmalemma and opening to the exterior via a pore. Monomorphic mature spermatozoa of S. feltiae are 5 μm in diam., bear pseudopods, and form chains of several cells joined by gap junctions. The dimorphic immature spermatozoa of S. tami form spermatozeugmata where the single giant megaspermatozoon (30-35 μm diam.) bears numerous tiny, 3 μm microspermatozoa, intimately attached to the megaspermatozoon surface by gap junctions. Mature megaspermatozoa from the uterus are motile cells 35-50 μm diam.; they have prominent pseudopods and convey immotile, 2 μm microspermatozoa towards the oviduct. Unlike many other invertebrates, sperm dimorphism in S. tami does not change the basic set and structure of organelles, only their number. The genus Steinernema has two strategies for sperm agglomeration: i) chains of monomorphic spermatozoa of normal size, as in S. feltiae; and ii) spermatozeugmata based on a dramatic size difference between spermatozoa formed in the testis, as exemplified by S. tami. According to the types of sperm agglomeration, the genus Steinernema is divided into two main clades.

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