Mohsen A. Moustafa

The effect of melatonin on eye lens of rats exposed to ultraviolet radiation.

We investigated the influence of exogenously administered melatonin on adult rats eye lenses exposed to ultraviolet radiation (UV) A and B ranging from 356-254 nm irradiation at 8 microW/cm(2). Rats exposed to this range of UV for 15 min for one week showed a significant (P<0.05) reduction in antioxidant enzymes activities; superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and elevated (P<0.001) lipid peroxidation served as an index of cellular damage by free radicals. UV-radiation significantly (P<0.001) elevated calcium ions (Ca(2+)) and lactate dehydrogenase (LDH) activity in lenses. Depleting animals of their stores of important intracellular antioxidant and elevating lenticular Ca(2+) by UV irradiation, may be the main cause of lens opacification. Melatonin injection with radiation significantly reduced (P<0.05) lipid peroxidation, Ca(2+) and (P<0.001) for LDH. When melatonin was injected after radiation, SOD and GSH-Px enzyme activities increased significantly (P<0.01), and lipid peroxidation, Ca(2+) levels and LDH activities were reduced significantly. Melatonin injection after UV radiation was as effective as melatonin treatment concurrent with UV irradiation. We conclude that melatonin may protect the eye lens from the damaging effects of UV exposure, and its actions protect lens from oxidative stress, elevating Ca(2+) levels, which are considered as an important causes of cataractogenesis.

In situ evaluation of the genotoxic potential of the river Nile: I. Micronucleus and nuclear lesion tests of erythrocytes of Oreochromis niloticus niloticus (Linnaeus, 1758) and Clarias gariepinus (Burchell, 1822)

This study aimed to investigate the genotoxic potential of chemicals present along the course of the river Nile using frequencies of micronuclei (MN) and nuclear lesions (NL) in erythrocytes of Nile tilapia Oreochromis niloticus niloticus and African catfish Clarias gariepinus, as biomarkers. Results showed that most of the physicochemical parameters detected and heavy metal concentrations were significantly higher in the water collected from the estuaries of the river Nile compared to other sites of the upper Nile. The frequencies of MN and NL in peripheral blood erythrocytes of Nile tilapia and African catfish were significantly higher in estuary sites in Damietta and Rosetta compared to upper sites. The lowest level of genotoxicity was observed at two sites (Aswan and Kena), considered to be less contaminated. Our results suggested that higher frequencies of MN and NL determined at Damietta and Rosetta sites may be indicative of damage produced by pollutants in these areas. The most remarkable result was that MN and NL frequencies appear to be strongly related to water quality at different sites examined, indicating that MN frequencies may serve as a reliable biomarker for testing genotoxicity in situ. The positive correlation between MN and NL induction suggested that NL may be a useful complementary assay for genotoxicity analyses when fish are used as experimental animals. It was also found that seasonal variations in MN and NL frequencies might contribute to a better understanding of genotoxic responses in the field. The use of fish as indicator organisms for monitoring the presence of genotoxic-inducing contaminants in the environment seemed justified because the effects of exposure to a “complex mixture” such as river water were obtained. Nile tilapia appears to be a more suitable bioindicator species than African catfish in studying genotoxic chemical pollution in the river Nile attributed to a higher sensitivity.

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

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.

Localization of connective tissue growth factor (CTGF) and transforming growth factor beta-2 (TGF-β2) during eye development of four species of birds

ABSTRACT Connective tissue growth factor (CTGF) and transforming growth factor (TGF-β2) have essential roles for structure, function, growth, and production of extracellular matrix during eye development. The current study aim was to examine the localization of CTGF and TGF-β2 by immunohistochemical labeling during eye development in four different habitat species of Egyptian birds i.e. chicken (Gallus gallus domesticus), duck(Cairina moschata), quail (Coturnix coturnix), and egret (Bubulcus ibis). Fertilized eggs were obtained to access pre-and post-hatching stages of developing eye. CTGF and TGF-β2 were detected in the inner non-pigmented epithelium layer of ciliary body during eye development of studied birds. Moreover, CTGF was well expressed in the developing sclera, but not expressed in the developing retina. On the contrary, expression of TGF-β2 was detected in the developing retina but was not detected in the developing sclera. The pattern of expression and distribution of CTGF and TGF-β2 in ciliary body, retina and sclera concluded the important cellular function of these growth factors during eye development of studied birds.

Blood Biomarkers in Nile tilapia Oreochromis niloticus niloticus and African Catfish Clarias gariepinus to Evaluate Water Quality of the River Nile

In this work, we explore new sights of biomarker research and establish the use of blood parameters and erythron profile in wild fish. Water quality assessment along the Nile course concluded higher mean values of the detected physicochemical parameters in water collected from downstream sites. The mean values of nearly all the detected haematological parameters were significantly lower in the blood of Nile tilapia and African catfish collected from downstream (contaminated) compared to upstream sites. Lower cellular and nuclear areas and cellular and nuclear shape factor were recorded in the erythrocytes of fish collected from downstream compared to those caught from upstream sites. This was confirmed by higher immature ratios of red cells in the blood of fish sampled from downstream sites. Karyorrhectic and enucleated erythrocytes were recorded to be higher in the blood of fish collected from downstream sites. The levels of all the selected biochemical variables in the blood of both fish species were recorded to be significantly higher in downstream sites. The detected blood variables and erythrocyte malformations were proven to be suitable for bio-monitoring of aquatic pollution. The results revealed speciesspecific differences in sensitivities, suggesting that Nile tilapia may serve as a more sensitive test species compared to African catfish.

Ultrastructure of the mouthparts and food habits of the Grapsid crab, Metopograpsus messor (Forskal, 1775) from different habitats of the Egyptian Red Sea Coasts.

Like all other decapods, the grapsid crab, Metopograpsus messor has mouth parts composed of six pairs of modified appendages. The present study revealed the structural significance of this complexity and the feeding habits of this species. Scanning electron microscope was used for examination of the mouth parts of the specimens collected from two different habitats. No differences were found neither in the structure of mouth parts nor in food analyses. The feeding habits showed that M. messor is opportunistic omnivore feeding on a wide variety of benthic organisms including algae, epifaunal animals as well as dead fish and other decayed animals in addition to higher plants particularly decomposed sea grass leaves and mangrove.