Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

Sorted by: relevance · author · university · dateNew search

You searched for subject:(Previtellogenic). Showing records 1 – 2 of 2 total matches.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters


University of Otago

1. Reid, Peter Mark. The effects of peptide hormones on GDF-9, BMP-15, StAR mRNA levels and steroid production in the previtellogenic ovary of the shortfinned eel .

Degree: 2011, University of Otago

It is unknown which factors are involved in regulation of early oocyte growth in oviparous vertebrates; in particular, the involvement of the oocyte-derived growth factors, growth differentiation factor-9 (GDF-9) and bone morphogenetic protein-15 (BMP-15) in teleost reproduction. The regulation of steroidogenic acute regulatory protein (StAR), the true rate- limiting step in steroidogenesis, has also been largely ignored in many fish species. The few studies on early oogenesis have pointed to roles for pituitary hormones, such as follicle stimulating hormone (FSH), luteinizing hormone (LH) and growth hormone (GH) as being possible regulators of GDF-9, BMP-15, StAR gene expression and steroid production. The main aims of this thesis were i) to examine BMP-15 and StAR mRNA levels throughout oogenesis in wild and artificially maturing New Zealand shortfinned eel, Anguilla australis, in vivo ii) to examine whether FSH, LH, GH or the metabolic hormone insulin-like growth factor-I (IGF-I) have any effect on GDF-9, BMP-15 or StAR mRNA levels in the previtellogenic (PV) ovary of A. australis, in vitro iii) to examine the effects of FSH on steroid production in the ovarian tissue of PV A. australis, in vitro. Both wild and artificially maturing eel cDNA was used to obtain BMP-15 and StAR mRNA levels at all stages of eel oogenesis. BMP-15 mRNA levels were found to significantly increase in wild females in early vitellogenesis (EV) compared with wild PV females (P < 0.01). No difference in BMP-15 mRNA levels was found in artificially maturing eels at different developmental stages. Levels of StAR mRNA throughout shortfinned eel oogenesis were found not to be significantly different in wild females in EV compared with wild PV females. A significant difference in StAR mRNA levels in artificially maturing eels at different developmental stages was found, with a peak at midvitellogenesis (MV) (P < 0.001). In vitro incubations of PV A. australis ovarian tissue with FSH, LH, GH or IGF-I were conducted and the mRNA levels of GDF-9, BMP-15 and StAR subsequently measured by quantitative real-time PCR (RT-PCR). No effect of FSH, LH or GH on either GDF-9 or BMP-15 mRNA levels was found during PV in A. australis. FSH was however, found to significantly increase StAR mRNA levels (P < 0.05) throughout PV. IGF-I had no effect on GDF-9, BMP-15 or StAR mRNA levels. To investigate the effect of FSH on steroidogenesis throughout PV, the levels of five steroid hormones; 11-ketotestosterone (11-KT), 11β-hydroxyandrostenedione (11-OHA), estradiol (E2), testosterone (T), 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) were measured in the ovary after 8 h incubation with FSH and tritium labelled pregnenolone (P5) in eel ringer. No change in steroid levels between controls and FSH treatments was found. High levels of 11-OHA and E2 were however, found to be produced in both control and FSH incubations. In conclusion, neither pituitary hormones nor IGF-I had any effect on GDF-9 or BMP-15 mRNA levels throughout PV in the shortfinned eel in vitro.… Advisors/Committee Members: Lokman, Mark (advisor).

Subjects/Keywords: Previtellogenic; Eel; Ovary

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Reid, P. M. (2011). The effects of peptide hormones on GDF-9, BMP-15, StAR mRNA levels and steroid production in the previtellogenic ovary of the shortfinned eel . (Masters Thesis). University of Otago. Retrieved from http://hdl.handle.net/10523/1686

Chicago Manual of Style (16th Edition):

Reid, Peter Mark. “The effects of peptide hormones on GDF-9, BMP-15, StAR mRNA levels and steroid production in the previtellogenic ovary of the shortfinned eel .” 2011. Masters Thesis, University of Otago. Accessed November 17, 2019. http://hdl.handle.net/10523/1686.

MLA Handbook (7th Edition):

Reid, Peter Mark. “The effects of peptide hormones on GDF-9, BMP-15, StAR mRNA levels and steroid production in the previtellogenic ovary of the shortfinned eel .” 2011. Web. 17 Nov 2019.

Vancouver:

Reid PM. The effects of peptide hormones on GDF-9, BMP-15, StAR mRNA levels and steroid production in the previtellogenic ovary of the shortfinned eel . [Internet] [Masters thesis]. University of Otago; 2011. [cited 2019 Nov 17]. Available from: http://hdl.handle.net/10523/1686.

Council of Science Editors:

Reid PM. The effects of peptide hormones on GDF-9, BMP-15, StAR mRNA levels and steroid production in the previtellogenic ovary of the shortfinned eel . [Masters Thesis]. University of Otago; 2011. Available from: http://hdl.handle.net/10523/1686


University of Otago

2. Wylie, Matthew John. Reproductive physiology of wreckfish (hāpuku) Polyprion oxygeneios in captivity .

Degree: University of Otago

Summary New Zealand’s flagship aquaculture species are currently the green-lipped mussel (Perna canaliculus), the Pacific oyster (Crassostrea gigas) and the chinook salmon (Oncorhynchus tshawytscha). However, important drivers to achieve growth of the aquaculture sector have been identified through the diversification of species being cultured and the development of innovative products. In response to this, the New Zealand National Institute of Water and Atmospheric Research (NIWA) has responded by conducting extensive research into the culture of the wreckfish species Polyprion oxygeneios – locally known as hāpuku or groper. Information is limited the reproductive biology, behaviour and life histories of both wild hāpuku and those maintained in captivity. In the wild, it is believed that breeding individuals migrate to deep and in many cases unfishable areas to spawn while wild-caught captivity-acclimated broodstock maintained under photo-thermal control communally spawn without hormonal intervention. However, despite the development of hatchery technologies to raise hāpuku larvae by NIWA, seed supply is still reliant on these wild-caught captivity-acclimated broodstock and significant issues bottlenecking production include variable egg quality and poor larval survival. It is now evident that the development of appropriate broodstock management strategies for an emerging aquaculture species like hāpuku requires the ability to identify, monitor and control ovarian growth, oocyte maturation and ovulation in stock. Research within this thesis makes a significant contribution to such requirements by studying first filial (F1) fish in captivity at various stages of the reproductive cycle. The first study has a basic focus examining ovarian development by RNA-seq on tissues at different stages oogenesis (see Chapter 2 for details). The aim of this study was provide a snapshot of the composite changes in gene expression associated with oocyte growth in hāpuku – particularly during the transition from previtellogenic to early vitellogenic stages of ovarian growth. Thirty-five differentially expressed genes were identified and upregulated between previtellogenic and early vitellogenic stages of development. Once these genes were grouped according to tentative functions, those associated with the respiratory electron transport chain, lipid metabolism, steroidogenesis and mineral/ solute transport were apparent. The second study centred around advancing puberty by examining the effects of several sex steroid and neuropeptide treatments on the pituitary-gonadal axis of pre-pubertal hāpuku in vivo (see Chapter 3 for details). While puberty could not be advanced, outcomes from this study included insights into the negative feedback effects of androgens on the pituitary-gonadal axis of pre-pubertal hāpuku and directions for future research towards the exploration of alternative treatments to advance puberty. In order to develop more appropriate broodstock management strategies, Chapter 4 aimed to describe ovarian… Advisors/Committee Members: Lokman, Pieter Mark (advisor).

Subjects/Keywords: BPG axis; wreckfish; groper; hapuku; hapuka; aquaculture; GnRHa; oocyte; Polyprion; vitellogenesis; kisspeptin; spawning; androgen; estrogen; oestrogen; 11KT; E2; oogenesis; F1; gonadotropin; Lh; Fsh; Transcriptome; RNA-seq; follicle-stimulating hormone; ovary; pituitary; kiss; luteinizing hormone; brain; gametogenesis; EVac; steroidogenesis; puberty; finfish; broodstock; temperature; photoperiod; plasma; RT-PCR; mRNA; cycle; reproductive; oxygeneios; NIWA; egg; egg quality; induction; gnrhr; lhr; fshr; aromatase; cyp19a; receptor; beta; glycoprotein; feedback; physiology; cativity; maturity; maturation; yolk; lipid; gamete; life-cycle closure; F2; HiSeq; previtellogenic; final oocyte maturation; fish; teleost; perciform; ovaries; ovulation; pre-pubertal; kiss2; dummy run; maiden; biopsy; cannulation; failure; seed; dysfunction

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Wylie, M. J. (n.d.). Reproductive physiology of wreckfish (hāpuku) Polyprion oxygeneios in captivity . (Doctoral Dissertation). University of Otago. Retrieved from http://hdl.handle.net/10523/7414

Note: this citation may be lacking information needed for this citation format:
No year of publication.

Chicago Manual of Style (16th Edition):

Wylie, Matthew John. “Reproductive physiology of wreckfish (hāpuku) Polyprion oxygeneios in captivity .” Doctoral Dissertation, University of Otago. Accessed November 17, 2019. http://hdl.handle.net/10523/7414.

Note: this citation may be lacking information needed for this citation format:
No year of publication.

MLA Handbook (7th Edition):

Wylie, Matthew John. “Reproductive physiology of wreckfish (hāpuku) Polyprion oxygeneios in captivity .” Web. 17 Nov 2019.

Note: this citation may be lacking information needed for this citation format:
No year of publication.

Vancouver:

Wylie MJ. Reproductive physiology of wreckfish (hāpuku) Polyprion oxygeneios in captivity . [Internet] [Doctoral dissertation]. University of Otago; [cited 2019 Nov 17]. Available from: http://hdl.handle.net/10523/7414.

Note: this citation may be lacking information needed for this citation format:
No year of publication.

Council of Science Editors:

Wylie MJ. Reproductive physiology of wreckfish (hāpuku) Polyprion oxygeneios in captivity . [Doctoral Dissertation]. University of Otago; Available from: http://hdl.handle.net/10523/7414

Note: this citation may be lacking information needed for this citation format:
No year of publication.

.