Usama M. Mahmoud

Effects of 4-nonylphenol on blood cells of the African catfish Clarias gariepinus (Burchell, 1822).

In the present work, the destructive effects of the 4-nonylphenol on one of the most economically important Nile fishes, namely African catfish (Clarias gariepinus) were studied. Apoptosis, erythrocytes alterations, micronucleus test and blood parameters count were used as biological indicators to detect those effects. After exposure to sublethal concentrations of 4-nonylphenol (0, 0.05, 0.08 and 0.1mg/l), apoptotic red blood cells with many malformations and micronucleated erythrocytes were recorded. Decrease in the blood parameters such as red blood cells (RBCs), hemoglobin (Hb), package cell volume (PCV), mean corpuscular hemoglobin concentration (MCHC), platelets, white blood cells (WBCs), lymphocytes, basophils, monocytes and increase in mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), neutrophils, eosinophils indicated the negative effects of 4-nonylphenol. It was concluded that, the 4-nonylphenol caused genotoxicity in erythrocytes with many malformations in shape and number indicated with other blood parameters.

Reproductive biomarkers to identify endocrine disruption in Clarias gariepinus exposed to 4-nonylphenol

The present study investigated the hormones concentrations and gonads alterations of Clarias gariepinus caused by sublethel concentrations of 4-nonylphenol (0, 0.05, 0.08 and 0.1 mg/l). The changes in the activities of the hormones after exposure to these sublethel doses of 4-nonylpenol referred to endocrine disruption in Clarias gariepinus in association with histopathological changes in reproductive tissues. The levels of thyroid stimulating hormone (TSH), triiodothyronine (T3), total thyroxine (T4), follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone concentrations significantly decreased (P<0.05) in the treated fish in comparison with control. 17-β-estradiol increased significantly (P<0.05) with 4-nonylphenol concentrations increase. Reduction in the gonadosomatic index was evident with increase of sublethal doses of 4-nonylphenol. The histopathological changes of NP-treated were recorded in gonads of Clarias gariepinus reflecting their sensitivity to NP-estrogenic like effects.

Ultraviolet radiation-A (366 nm) induced morphological and histological malformations during embryogenesis of Clarias gariepinus (Burchell, 1822)

Exposure to ultraviolet radiation has been associated with variety effects in many organisms ranging from molecular and tissue damage to population level effects. The exposure of embryos of the catfish, Clarias gariepinus (Burchell, 1822) to 366nm UVA at different doses 15, 30 and 60 min resulted in the hatching time delayed to 29 h-post-fertilization stage (29 h-PFS) in comparison with normal hatching time of 22h-PFS at 29 degrees C. In embryos exposed to 15 min/UVA, 30 min/UVA and 60 min/UVA the total percentage of hatched embryos/fertilized eggs were 90%, 89% and 85%, respectively, while in control was 95% at 29 h-PFS. The total percentage of mortality/ hatched embryos were (1-14)%, (2-22)%, (2-23)% and (3-40)% for control, 15 min, 30 min and 60 min groups, respectively, at 40 h-PFS. Also as a result some morphological malformations; (yolk sac oedema, body curvature, fin blistering, and dwarfism) were revealed. These destructive effects were also confirmed by histopathological changes in gills, eyes, intestinal tract, spinal cord, notochord, liver, skin and kidney. The results confirm that exposure to UVA caused an exposure time-dependent delay in hatching rate and reduced the percentage of the hatched embryos but the mortality rate increased with increase of the exposure time to UVA.

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.

Histopathological Alterations in some Body Organs of Adult Clarias gariepinus (Burchell, 1822) Exposed to 4-Nonylphenol

Endocrine-disrupting chemicals (EDCs) include synthetic and naturally occurring chemicals that affect the balance of normal functions in animals (Razia et al. 2006). It has been found that exposure to natural and synthetic estrogenic chemicals may adversely affect wildlife and human health (Colborn et al. 1993). In vitro exposures (Soto et al. 1992; Soto et al. 1994; Toomey et al. 1999) have confirmed the effects of EDCs on tissue structure and cellular processes. Nonylphenol ethoxylates (NPEs) are EDCs which are used globally in the production of plastics, pesticides, and cleaning products and are present in sewage effluents around the world (Talmage, 1994). It has been reported that NP is the most important degradation product of NPEs because of its enhanced resistance towards biodegradation, toxicity, ability to bioaccumulate in aquatic organisms, and estrogenicity (Ahel et al. 1994). NP is found in surface waters, aquatic sediments, and ground water (Bennie, 1999; Talmage, 1994) and it is estrogenic in various aquatic animals (Nimrod and Benson, 1996; Talmage, 1994; Servos, 1999).

Surface architecture of the oropharyngeal cavity and the digestive tract of Mulloidichthys flavolineatus from the red sea, Egypt: A scanning electron microscope study

Surface architecture of the buccal cavity and the surface organization of the luminal mucosa of the oesophagus, stomach, and intestine of the carnivorous fish M. flavolineatus from the Red Sea were studied by using SEM. The results revealed that M. flavolineatus has four kinds of teeth; curved-blunt, wedge-shaped, flattened crowns, molariform and papilliform. Three types of taste buds (type I, II and III) were recorded in the oropharyngeal cavity. It was observed that taste buds and teeth are co-located in the pharyngeal region. Characteristic patterns of microridges of the surface cells in the oral cavity and oesophagus were observed. Mucous cells are distributed in the lining of the mouth cavity, oesophagus, stomach, and intestine. Characteristic patterns of mucosal folds throughout the alimentary canal, concerning oesophagus, stomach, and intestine were revealed. Numerous gastric pits, which represents the emergence of the gastric glands, were recorded in the anterior and middle regions of the stomach. Complex patterns of the folds and mucous cells were recorded in the intestinal mucosa. These results were discussed with other teleost fishes.

Biochemical response of the African catfish, Clarias gariepinus (Burchell, 1822) to sublethal concentrations of mercury chloride with supplementation of selenium and vitamin E

The present investigation aimed to determine the toxicological effects of mercury chloride on biochemical parameters of the widely consumed African catfish, Clarias gariepinus. Adult specimens of Clarias gariepinus were exposed to sublethal concentrations (0.04 and 0.12 ppm) of mercury chloride for 7, 14, 21 and 28 days. Empirical data of results obtained were subjected to statistical analysis of variance (ANOVA) to test the effects of mercury, selenium, vitamin E and exposure periods. The mean values of Na+, Urea, Creatinine, AST, ALT and ALP were significantly increased from the control values, while mean values of K+, Glucose and Triglyceride were significantly decreased from the control values. Selenium and Vitamin E supplementation play appositive role in detoxification of mercury toxicity specially the low dose. The results suggest that mercury chloride can negatively affect the physiology of fish. It was observed that supplementation of selenium and vitamin E decreases the toxic effect of mercury.

SDS-PAGE technique as biomarker for fish toxicological studies

Graphical abstract

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.

Characterization of Blood cells and Hematological and Biochemical Parameters in Diplodus noct from the Red Sea, Egypt

The main aim of the present study was to obtain a basic knowledge of the hematology and biochemistry of the Red Sea seabream Diplodusnoct. The samples were collected from the Red sea at Hurghada, Egypt. Baseline values for hematological parameters including Red Blood Corpuscles (RBCs), Hematocrit (HCT), Hemoglobin (Hb), Mean cell hemoglobin concentration (MCHC), mean cell hemoglobin (MCH) and mean cell volume (MCV) and biochemical parameters including AST, ALT, glucose, total protein and urea were established. Erythrocytes, thrombocytes and three types of leucocytes, lymphocytes, neutrophils and eosinophils, were distinguished, characterized and measured. The morphological and cytochemical aspects of peripheral blood cells of Diplodusnoct were studied by light microscopy. This investigation may be helpful as a tool to monitor the health status of Diplodusnoct and will grant early detection of clinical pathology.