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Egg production in Brugia pahangi(Nematoda: Filarioidea)

Published online by Cambridge University Press:  06 April 2009

C. J. Delves
Affiliation:
Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA
H. H. Rees
Affiliation:
Department of Biochemistry, University of Liverpool
R. E. Howells*
Affiliation:
Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA
*
Reprint requests to Professor R. E. Howells.

Summary

Oogenesis in Brugia pahangi has been studied by means of the aceto-orcein chromosomal squash technique and light-microscope autoradiography. The use of colchicine has demonstrated a 2–3 mm terminal germinative zone within the ovary, in which continuous and rapid mitotic division of germ cells occurs. In 80% of the gonads, oocytes within a 1–2 mm length of the ovary proximal to the germinative zone were at the prophase of meiosis I. Primary oocytes with markedly less condensed chromatin, apparently interphase cells, were observed in the corresponding region of the ovary in the remaining 20% of material examined. A cyclical or phased development of primary oocytes is suggested. Autoradiographic studies, concerned with the incorporation of [5-3H]uridine into germ cells of B. pahangi in vitro, further suggest that the onset of meiotic prophase is associated with the initiation of high RNA synthetic activity. Following meiotic prophase, oocytes complete meiosis I before entering a period of growth during which the chromatin material is decondensed. Recondensation of chromosomes prior to meiosis II is only observed after fertilization within the seminal receptacle. On completion of meiosis II, with the extrusion of a polar body, the haploid chromosome complement of the female unites with that of the male, re-establishing the diploid number of the zygote (2n = 10).

Type
Research Article
Copyright
Copyright © Cambridge University Press 1989

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