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Title: ULTRASTRUCTURE OF THE MALE GONAD AND SPERMATOGENESIS IN THE LESION NEMATODEPRATYLENCHUS PENETRANS (NEMATA: PRATYLENCHIDAE)

Author
item ENDO, BURTON - RETIRED, USDA, ARS
item ZUNKE, ULRICH - UNIVERSITY OF HAMBURG
item WERGIN, WILLIAM

Submitted to: Journal of Helminthological Society of Washington
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: A microscopic worm, known as the lesion nematode, is one of the most economically destructive parasites of plants. This nematode has world-wide distribution and consistently causes extensive damage to crop plants in the United States. Its economic impact is directly related to decreased yields and destruction of plants, as well as indirectly related to exposing plants to many other soil borne microorganisms that cause damage to a wide range of annual and perennial crops. To develop alternatives to chemical nematicides that may contaminate groundwater, a study was undertaken to increase our understanding about the reproductive anatomy of this nematode. This study used an extremely powerful instrument, known as a transmission electron microscope, to provide new information on the structure of the reproductive system of this nematode. This information will help scientists identify weak links in the reproductive process that can be manipulated and used to develop alternatives to chemical nematicides.

Technical Abstract: Transmission electron microscopy is used to elucidate the structure of the male reproductive system of P. penetrans. The male gonad has an elongated telogonic testis with a single row of spermatogonia in the germinal zone. In the growth zone, these cells increase in size and form spermatocytes that undergo meiosis and divide into spermatids. Synaptonemal complexes in the spermatocytes signify the pachytene stage of the first meiotic division. Spermatids are characterized by fibrous bodies surrounding prominent spheroid nuclei. Spermatids in the seminal vesicle differentiate into spermatozoa that accumulate in the posterior region of the vesicle. During this process, filopodia decrease in number, residual bodies are lost, and sperm nuclei become irregularly shaped. The electron transparent region of the sperm extends into a pseudopod that controls the crawling form of motility that is typical of many nematode species. Seminal fluid produced by cells of the vas deferens accumulates and appears to cause aggregation of sperm within the seminal vesicle. Sperm morphology in the spermatheca of female specimens is similar to that in the male vas deferens.