Profiles for plasma gonadotropin, estradiol, and vitellogenin were obtained in female brown trout during the seasonal reproductive cycle. The accumulation of yolk lipophosphoprotein (phosvitin) in the gonad was also followed. Plasma estradiol and vitellogenin concentrations rose progressively and parallel increases in ovary yolk phosvitin were observed. Gonad development continued while plasma ...

Alternative reproductive tactics are characterized by the occurrence of discrete alternative morphs that differ in behavioural, morphological and physiological traits within the same sex. Although much effort has been made to describe the behaviour, morphology and physiology of such alternative morphs, less effort has been invested investigating how much overlap there is in the characteristics ...

Proses induk lele (Clarias gariepinus Burchell) betina menjadi matang gonad secara alami memakan waktu hingga 2-3 bulan, dengan tingginya permintaan benih diperlukan percepatan proses pematangan agar dapat terpenuhi, salah satunya melalui pemberian hormon ethinylestradiol. Kandungan optimum ethinylestradiol pada tubuh akan mempercepat vitellogenesis sehingga memacu pertumbuhan oosit dan kematan...

In the present study, Xenopus laevis tadpoles were chronically exposed to four concentrations of the synthetic gestagen Levonorgestrel (LNG; 10(-11), 10(-10), 10(-9), and 10(-8)M) starting at Nieuwkoop and Faber (NF) stage 48 until completion of metamorphosis. At NF 58 and 66, brain-pituitary and gonad samples were taken for gene expression analyses of gonadotropins and gonadal steroidogenic en...

Incursion of the urchin Centrostephanus rodgersii into Tasmania, Australia, and its establishment at high densities raises questions about its potential interactions with another large herbivore on subtidal rocky reefs, the commercially fished abalone Haliotis rubra. Surveys on the southeast coast of Australia show a negative relationship between densities of C. rodgersii and H. rubra at severa...

Gonad characteristics and reproductive cycle in the acmaeid Collisella subrugosa from Northeastern Brazil were investigated. The individuals were collected monthly from February 1993 to April 1994 at Farol do Mucuripe Beach, Fortaleza, Ceará, Brazil. There is no external characteristic on the shell and the soft body structures except the gonad that allows sex differentiation. The gonad of limpe...

The functional, nutritional, and antioxidative properties of hydrolyzed herring and herring byproducts (head and gonad) were evaluated. All freeze-dried herring fish protein hydrolysate (FPH) powders were light yellow and contained 77% to 87% protein. The degree of hydrolysis was 18.3%, 13%, 13%, and 10.1%, respectively, for head, whole fish, body, and gonad after 75 min digestion. All FPH powd...

The creation of sexual dimorphism in the gonads is essential for producing the male and female gametes required for sexual reproduction. Sexual development of the gonads involves both somatic cells and germ cells, which often undergo sex determination by different mechanisms. While many sex-specific characteristics evolve rapidly and are very different between animal species, gonad function and...

This study investigated the effect of different photoperiods (14L: 10D, 12L:12D and 10L:14D) on the gonadal development and GtH mRNA expression in the pituitary of damselfish. The results showed that gonadosomatic index (GSI) was significantly lower in shot photoperiod (10L:14D), in comparison with other photoperiodic group during the spawning season. After 60 days treatment, histological analy...

The gonad in Caenorhabditis elegans is an important model system for understanding complex morphogenetic processes including cellular movement, cell fusion, cell invasion and cell polarity during development. One class of signaling proteins known to be critical for the cellular events underlying morphogenesis is the Rho family GTPases, particularly RhoA, Rac and Cdc42. In C. elegans orthologues...