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Studies on some aspects of the development of Trichinella spiralis in mice
Başlık:
Studies on some aspects of the development of Trichinella spiralis in mice
Yazar:
Fatunmbi, Olabantale Olubunmi, author.
ISBN:
9780438059047
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (163 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 76-08C.
Advisors: R. G. Bruce.
Özet:
This dissertation describes light and electron microscope studies of the growth of pre-adult and adult Trichinella spiralis, the development of the reproductive organs, oogenesis and embryonation in the female worm in both primary and challenge infections in the NIH strain of mouse. It is shown that in a primary infection in this strain of mouse, growth of pre-adult and adult worms is completed by the fifth day post-infection, and subsequently that an immunologically-mediated expulsive response does not cause decrease in size of the adult worms before they are expelled from the host on or about the eleventh day post-infection. In challenge infections, growth of the pre-adult and adult worms was severely retarded and they were expelled on or about the fifth day post-infection. Ultrastructural studies confirmed that the germinal region of the reproductive tract is hologonic and that maturation of spermatozoa and oocytes occurs as early as the second twenty-four hours post-infection in both primary and challenge infections. The process of embryonation within the uterus of the female worm is described and confirms that gastrulation is of the embolic apolytic type. Cellular differentiation is not evident until the embryo has elongated and adopted a U-shape where upon differentiation commences in the anterior and posterior regions of the embryo while cellularisation is continuing in the central part of the body. The cells of the hypodermis, i.e. the outermost layer of cells which give rise to the lateral hypodermal cords, the nerve cords and secrete the cuticle, are the first cells to differentiate and are closely followed by the cells forming the body wall muscle. The oesophagus is the first part of the alimentary tract to be distinguished. Embryonic development is rapid and may be completed within 3½ to 4 days from the time that oocytes are liberated from the ovary and fertilized in the proximal region of the uterus. This time scale of development operates until the 8th or 9th day post-infection but is, there-after, retarded slightly. In a challenge infection, in utero embryonation may be completed in 3½days but as in the later phase of a primary infection, there appears to be a slight retardation of the rate of embryonic development. This slight reduction in the rate of embryonation explains a small part of the known reduction in fecundity of adult T. spiralis in the terminal phase of an intestinal infection. However, the most significant finding in this regard is that in a primary infection, the immunologically mediated host responses which lead to explusion of the adult worms have a profound effect on oogenesis as early as the 6th day post-infection. This is manifest as a very significant reduction in the number of oocytes produced by and released from the ovary and results in many fewer juvenile worms being liberated from the adult female 3½ to 4 days later. This very significant effect on oogenesis is confirmed in T. spiralis recovered from a challenge infection in such worms, oogenesis ceases by the third day post-infection. Thus it is clear that the immunologically-mediated host responses have a hitherto unknown remarkably early effect on the fecundity of Trichinella spiralis by affectingoogensis. The functional component of the host response is probably antibody but the effector mechanisms are unknown.
Notlar:
School code: 0547
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(684681.1) | 684681-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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