+ Site Statistics
References:
54,258,434
Abstracts:
29,560,870
PMIDs:
28,072,757
+ Search Articles
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ PDF Full Text
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Translate
+ Recently Requested

Reproduction and sexual development in a fresh water gastrotrich 1. oogenesis of parthenogenic eggs gastrotricha



Reproduction and sexual development in a fresh water gastrotrich 1. oogenesis of parthenogenic eggs gastrotricha



Zoomorphology (Berlin) 104(1): 33-41



Post-embryonic development of parthenogenic eggs of Lepidodermella squammata was studied by light microscopy and EM in animals of known age and reproductive history. Each bilateral gonad initially contains 8 cells. No mitotic proliferation occurs during parthenogenic egg development. Germ cells are tightly clustered, have smooth plasma membranes with no interconnections and are uninucleate. There is no surrounding ovary or oviduct. At hatching, 2 cells in each gonad are identifiable as parthenogenic eggs. The enlarged nucleolus of the most mature egg has already attained the morphology that persists throughout vitellogenesis, with intertwined granular and fibrillar threads. Less mature eggs have earlier stages of nucleolar development and lack indications of meiotic events. Parthenogenic eggs enter vitellogenesis singly, with formation of rough endoplasmic reticulum and active Golgi complexes, and the accumulation of lipid, yolk and various granules. The shell is formed in situ; the spines elongate after egg deposition. Most animals produce 4 parthenogenic eggs, which undergo immediate development (tachyblastic eggs). Resting (opsiblastic) eggs are rare in isolation culture. Both types of eggs are produced only prior to the formation of sperm and primary oocytes. The absence of synaptonemal complexes, which would indicate synapsis of homologous chromosomes in prophase of meiosis I, implies that parthenogenesis is by apomixis in L. squammata.

(PDF emailed within 1 workday: $29.90)

Accession: 006315515

Download citation: RISBibTeXText


Related references

Reproduction and sexual development in a fresh-water gastrotrich. Life history traits and the possibility of sexual reproduction. Transactions of the American Microscopical Society 105: 109, 1986

Developmental change in oocytes following parthenogenic reproduction in the fresh water gastrotrich lepidodermella squammata. American Zoologist 21(4): 988, 1981

Reproduction and sexual development in a freshwater gastrotrich. 3. Postparthenogenetic development of primary oocytes and the X-body. Cell and Tissue Research, 2363: 629-636, 1984

Reproduction and sexual development in a freshwater gastrotrich. 2. Kinetics and fine structure of postparthenogenic sperm formation. Cell and Tissue Research 236(3): 619-628, 1984

Species composition and dominance structure of Gastrotrich (Gastrotricha) assemblages in water bodies of different trophic status. Hydrobiologia 339(1-3): 141-148, 1996

Species composition and dominance structure of Gastrotrich Gastroiricha Gastrotricha assemblages in water bodies of different trophic status. Hydrobiologia 339.1-3 (november 15): 141-148, 1996

Partial trophic analysis of a fresh water gastrotrich. ASB Bulletin 22(2): 41-42, 1975

Phylogeny of Gastrotricha: a morphology-based framework of gastrotrich relationships. The Biological Bulletin 2): 9-305, 2000

Spectral sensitivity in a fresh water gastrotrich lepidodermella squamatum. Experientia (Basel) 36(7): 830-831, 1980

Existence of sperm in a fresh water gastrotrich lepidodermella squammata. American Zoologist 18(3): 631, 1978

Tetranchyroderma bronchostylus sp nov, the first known gastrotrich Gastrotricha with a sclerotic canal in the caudal organ. Marine Biology Research 8(9): 885-892, 2012

First finding of a microsporidian parasite in the gastrotrich, Turbanella lutheri (Gastrotricha: Macrodasyida). Protistology, 11: 17-19, 1999