Showing 4 results for Mojazi Amiri
Volume 3, Issue 2 (6-2015)
Abstract
The pollution of aquatic ecosystems may affect natural reproduction of fish populations by decreasing the fertilization efficiency. Among the various sources of pollution, heavy metals are important group, being found in both freshwater and marine environment. The present study investigated changes of sperm characteristics of Caspimyzon wagneri when exposed to Manganese (Mn). Spermatozoids were exposed to 0 (control), 0.01, 0.1, 1, 10, 100 and 1000 mg l‑1 of Mn, duration of sperm motility and percent of motile sperms were measured using a light microscope and digital camera as a semi-quantitative method. Total duration of spermatozoids motility decreased with increase of Mn concentration in all treatments. This study indicated that Mn could seriously affect the reproductive success of the Caspian lamprey in a polluted environment through decreasing the duration of spermatozoid motility and possibly fertilization and hatching rates. Hence, contact to this metal could decrease the survival rate of this endangered species, especially during the reproduction.
Volume 3, Issue 3 (Number 3 - 2001)
Abstract
In order to determine the most effective hormones on the in vitro oocyte maturation
(germinal vesicle breakdown - GVBD) in a hybrid sturgeon bester, ovarian follicles were
incubated at the migratory nucleus stage in the presence of several steroids, gonadotropin
preparations and forskolin. Occurrence of GVBD and 17,20β-dihydroxy-4-pregnen-3 -one
(DHP) production were followed during an experimental period of one year of germinal
vesicle (GV) migration. From all the steroids tested, three progesterone derivatives-17α-
hydroxyprogesterone (17αOHP), 17, 20β, 21-trihydroxy-4-pregnen-3-one (17, 20 β, 21-
triol), and DHP-were the most potent steroid inducers of GVBD, followed closely by deoxycorticosterone
(DOC). No GVBD responses were found in ovarian follicles in July
when the GV was still central. The responsiveness increased gradually from then and
reached its peak in November when the GV had migrated fully towards the oocyte periphery.
Their potencys gradually declined later from December and the oocytes lost their
ability to mature the next July when degeneration set in. DHP production by ovarian follicle
during successive months of nucleus migration demonstrated a relatively similar pattern
of GVBD frequencies. These results indicated again a relevant role for DHP on oocyte
maturation in the bester and also suggested that GV localization along with in vitro
oocyte maturation assay can be used as practical tools for selecting the appropriate individuals
in exogenous induced spawning in bester.
Volume 6, Issue 3 (Summer 2018)
Abstract
Aims: The phytoestrogen, genistein and β-sitosterol, naturally occurring compounds found in soy products and pulp and paper mill effluent, respectively, could act as endocrine disrupting compounds (EDC) in the environment. The aim of this study was to evaluate the effects of β-sitosterol and genistein on the early life stages of Kutum (Rutilus kutum), specifically developing post-fertilized embryos.
Materials and Methods: In this experimental study, Kutum’s fertilized egg exposed to 3 different levels of genistein and β-sitosterol (10, 50, 500ng.l-1, respectively) up to 7 days post-fertilization (dpf). At the end of the research period, newly hatched larvae were sampled and testosterone (T), 17β-estradiol (E2), Aromatase and ethoxyresorufin-O-deethylase (EROD) were measured according to standard protocols. One-way analysis of variance (ANOVA), Duncan multiple range test and SPSS 17 software were used for data analyses.
Findings: A high level of genistein lead to increased 17β-estradiol, testosterone concentration and aromatase activity. Also, β-sitosterol treated embryos (500ng.l-1) showed a high level of testosterone and EROD as compared to the control group. While other treatment had no significant effect.
Conclusion: It seems that β-sitosterol and genistein could effect on the endocrine system of Kutum embryos by altering steroid biosynthesis and disturb enzyme activity. So it could lead to change the population structure and reduce reproduction performance of Kutum in the long period.
D. Mohammadrezaei, B. Mojazi Amiri, M.a. Neamat-Alahi,
Volume 7, Issue 3 (Summer 2018)
Abstract
Aims: A wide range of chemical endocrine disrupters modifies DNA methylation. Like a weak class of estrogens, phytoestrogens can affect aquatic animal reproduction and disturb the structure of endocrine systems.
Materials and Methods: In order to study the epigenetic effects of genistein and β-sitosterol, 49 female adults (for about 21 days) and fertilized eggs (until hatching time) of Kutum’s exposed to 3 different levels of genistein and β-sitosterol (10, 50, 500ng/l). At the end, the liver, the ovaries, and embryos were sampled and methylation-sensitive amplified polymorphism (MSAP) was used to evaluate the level of DNA methylation.
Findings: According to result the fish exposed to high level of β-sitosterol shown hypo DNA methylation in the liver. Compared with control, both of these compounds could effect on the ovary and embryos DNA methylation pattern. The result showed, whole genome methylation had a different pattern in the liver, ovary, and embryos, which treated by 500ng/l of β-sitosterol.
Conclusion: Methylation change pattern can be changed depends on the type of tissue and structure and level of the phytoestrogen compounds. According to this study, genistein and β-sitosterol could affect reproduction and embryo development by changing molecular indices. It seems that these compounds could affect the endocrine system of Kutum and reduce reproduction performance of Kutum in the long period.
