Ultrastructural studies of the morphological variations of the egg surface and envelopes of the African catfish &lt;em&gt;Clarias gariepinus&lt;/em&gt; (Burchell, 1822) before and after fertilisation with a discussion of fertilisation mechanism

Mekkawy, Imam A.; Osman, Alaa G. M.

doi:10.3989/scimar.2006.70s223

Cited by 16 publications

(13 citation statements)

References 46 publications

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“…Ripe oocyte membrane of E. teres had four distinct layers: an outer follicular epithelial layer, a median zona radiata (outer zona radiata + inner zona radiata) and inner cortical alveoli. Mekkawy and Osman [40] who reported that oocyte membrane of C. gariepinus had four distinct layers: an outmost follicular epithelial layer (outer theca + inner granulose), a median zona radiate, and inner cortical alveoli. According to Riehl and Greven [41] many oviparous teleosts exhibited a division of the zona radiata into two or more layers.…”

Section: Discussionmentioning

confidence: 99%

Reproductive Biology of Round HerringEtrumeus teres(Dekay,1842) from the Egyptian Mediterranean Water at Alexandria

et al. 2011

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Maturity stages of round herring Etrumeus teres were divided anatomically into six stages. Monthly distribution of such maturity stages showed that E. teres had prolonged spawning season extended from December to May for females and to July for males. The observed sex ratio was 1 : 2 (male: female). Gonadosomatic index (GSI) values were high during breeding season for both sexes. Hepatosomatic index (HIS) values for females increased from December to April and from December to July for males. Both sexes of E. teres showed the same correlation between GSI and HSI during their breeding season. The absolute and relative fecundity increased with increasing of length and weight. Histologically, the ovarian cycle of E. teres was classified into six stages and the testicular cycle into five stages. Female of E. teres was a multiple spawner and had prolonged spawning season with a group-synchronous ovarian which contained oocytes at all stages of development. Also, different sizes of spermatocytes at different developmental stages of maturation were observed during the same season. This may reflect the suitability of the specific reproductive behavior of male and its adaptation to the prolonged spawning season with females.

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Section: Discussionmentioning

confidence: 99%

Reproductive Biology of Round HerringEtrumeus teres(Dekay,1842) from the Egyptian Mediterranean Water at Alexandria

et al. 2011

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“…Congruently, Osman et al (unpublished data) recorded that lead has a negligible effect on the degree of DNA damage in the prehatching stage (30 h-PFS) in comparison with the post-hatching stages (48 h-PFS-168 h-PFS), due to the presence of the chorion, which protects the embryos. Mekkawy and Osman (2006) postulated earlier that the chorion of C. gariepinus started its hardening process 3 h after fertilisation, providing protection from lead 6 h after fertilisation. This hypothesis was first suggested by Nguyen et al (1999) with regard to heavy metal accumulation but is now further supported by the findings on reduced genotoxicity in pre-hatching stages.…”

Section: The Normal Ontogenetic Variations In Enzyme Activitiesmentioning

confidence: 99%

Effects of lead nitrate on the activity of metabolic enzymes during early developmental stages of the African catfish, Clarias gariepinus (Burchell, 1822)

Osman

Mekkawy

Verreth

et al. 2006

Fish Physiol Biochem

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“…Commonly used terms for this outer covering include chorion, zona pellucide, radiate membrane, egg membrane, vitelline membrane, vitellin envelope, egg shell (Yamagami et al, 1992;Wekkawy and Osman, 2006).…”

Section: Terminology Of Zona Radiatementioning

confidence: 99%

“…A key feature of teleost evolutionary success is their reproductive system, which must be functional in all aquatic environmental conditions. Much of the existing knowledge of the mechanisms involved in teleost fertilization is based on a few small model species such as zebrafish, medaka and bitterling, which have no real commercial value (Coward et al, 2002;Wekkawy and Osman, 2006). The Zona radiata in fish oocyte has three different sequential layers, including the oocyte plasma membrane or oolemma in the inner side, the Zona radiata in the middle and the follicle epithelium in the outer side.…”

Section: Introductionmentioning

confidence: 99%

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A study on ultrastructure of zona radiata during oocyte development of zebrafish (Danio rerio)

Koç¹

2010

J FisheriesSciences.com

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Fine structures of the zona radiata in zebrafish, Danio rerio, is examined and compared. The zona radiata (called as zona pellucid in mammals), is a porous structure located between oolemma and follicle cell epithelium in fish, has various functions. The zona radiata is an inner connection surface that regulates essential transition from follicle cells to oocytes and from oocytes to follicular layer. In this study, it is aimed to examine changeable and distinct structure of the zona radiata during oocyte development in zebrafish, which is a member of teleosts fish family. The structure of zona radiata were examined using light and transmission microscopy. The structure of zona radiata showed a morphological difference among the different species. The zona radiata structure could not be seen under light microscope in the pre-vitellogenic phase, but it was seen as a thin line form at the edge side in the early vitellogenic phase. In the following phases, the tendency to become thicker zona radiata was observed. The existence of microvillus structures, which lie from the zona radiata to follicle cell layer and from this layer to the zona radiata, was observed by means of electron microscope. It was assumed that the oocyte ensures communication between two sides through microvillus structures. Özet:Zebra balığında zona radiatanın ince yapısı incelendi ve karşılaştırıldı. Balıklarda oolemma ile folikül hücre epiteli arasında bulunan gözenekli bir yapı olan zona radiata (memelilerde zona pellusida), pek çok görevi yerine getirir. Zona radiata, granulosa hücrelerinden oositlere, oositlerden foliküler tabakaya gerekli hareketi düzenleyen bir iç alış-veriş yüzeyi gibi düşünülmektedir. Bu çalışmada amacımız, kemikli balık türü olan Zebra balığı (Danio rerio)'nda oosit gelişimi esnasında Zona radiatanın değişken, özgün yapısını incelemektir. Zona radiatanın yapısı ışık ve elektron mikroskobu kullanılarak incelendi. Farklı türler arasında zona radiata yapısı morfolojik farklılıklar gösterdi. Previtellojenik evrede zona radiata yapısı ışık mikroskobunda görülmedi, ancak erken vitellojenik evrede kenar bölgede ince çizgi halinde seçildi. İlerleyen evrelerde zona radiatanın kalınlığında artma gözlenmedi. Zona radiatadan folikül hücre tabakasına doğru uzanan, folikül hücre tabakasından da zona radiataya uzanan mikrovillus yapılarının varlığı elektron mikroskobu ile izlendi. Bu mikrovillus yapılarının aracılığı ile oositin iki yönde iletişimi sağladığı gösterildi.

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Ultrastructural studies of the morphological variations of the egg surface and envelopes of the African catfish <em>Clarias gariepinus</em> (Burchell, 1822) before and after fertilisation with a discussion of fertilisation mechanism

Cited by 16 publications

References 46 publications

Reproductive Biology of Round HerringEtrumeus teres(Dekay,1842) from the Egyptian Mediterranean Water at Alexandria

Reproductive Biology of Round HerringEtrumeus teres(Dekay,1842) from the Egyptian Mediterranean Water at Alexandria

Effects of lead nitrate on the activity of metabolic enzymes during early developmental stages of the African catfish, Clarias gariepinus (Burchell, 1822)

A study on ultrastructure of zona radiata during oocyte development of zebrafish (Danio rerio)

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