Imam Mekkawy

Imam Mekkawy
Taif University · Department of Biology

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42
Publications
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1,096
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Publications

Publications (42)
Article
In the present study, the neutral comet assay was applied for determination DNA double strand breakage in the African catfish Clarias gariepinus exposed variable concentrations and size of silver nanoparticles and ions. The parameters, tail % DNA; tail length, tail area; tail intensity; tail moment, olive tail moment, head mean intensity exhibited...
Article
Full-text available
Although, the 4-NP effects on fish’s reproductive hormones was assessed in several studies using adults’ models; however, the effect of this endocrine disruptor on immature fish’s reproductive hormones was not addressed commonly. This study aimed to study the reproductive toxicity and recovery associated with 4-nonylphenol exposure in juvenile Afri...
Article
Objective Although few studies have been done to evaluate the neurotoxic effect of 4-nonylphenol on the aquatic fauna, there is a shortage in knowledge about the effect of the dose-dependent damage of 4-NP in juvenile of C. gariepinus. So, the present study aims to investigate the neurotoxic effects of 4-NP in juvenile of Clarias garepinus through...
Article
Full-text available
The role of the liver is the major site of detoxification and metabolism, so it was considered as a target organ in toxicological studies. The present study investigates the potential protective effects of Amphora coffeaeformis extract against hepatotoxic effects in African catfish, Clarias gariepinus induced by arsenic. The fish Clarias gariepinus...
Article
Full-text available
The heavy metals have different adverse impacts on different life stages of fish species with attempts to use natural antioxidants to counteract their effects. So, the present study investigated the potential protective effects of Amphora coffeaeformis extract against arsenic-induced hemato-biochemical alterations in African catfish, Clarias gariep...
Article
Full-text available
The current study investigates the hepatotoxic effects of two acute doses of silver nanoparticles (AgNPs) and silver nitrate (AgNO3) on African catfish (Clarias garepinus) using biochemical, histopathological, and histochemical changes and the determination of silver in liver tissue as biomarkers. AgNPs-induced impacts were recorded in some of thes...
Article
Full-text available
The present study investigates the nephrotoxic effects of two acute doses of silver nanoparticles (AgNPs) and silver nitrate (AgNO3) on the African catfish, Clarias garepinus using biochemical, histochemical and histopathological changes as biomarkers. AgNPs-induced impacts were recorded in some of these characteristics on the bases of their size (...
Article
Full-text available
This study investigates the effects of silver nanoparticles (AgNPs) and silver nitrate (AgNO3) on gills and muscles in African catfish (Clarias garepinus). Changes in bioaccumulation, histopathological, and histochemical were used as biomarkers. The effects of AgNPs were recorded in some of these properties based on their size (20 and 40 nm) and th...
Article
The present study investigates the hemotoxic and cytotoxic impacts of two acute doses of silver nanoparticles (AgNPs) on the African catfish, Clarias garepinus in comparison to the impact of AgNO ⁠ 3 and the control fish. Ag-NPs-induced impacts were recorded on some biological and hematological indices of that species on the bases of their size (20...
Article
The present study aims to investigate the effects of methyltestosterone on monosex farmed tilapia, Oreochromis niloticus by detection of apoptosis, micronucleus and alterations of erythrocytes. Fishes were obtained from four localities (Assiut as a control and Beheira, Alexandria and Kafr EL-Sheikh; three farms from each governorate as farmed monos...
Book
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the parasites infecting the internal organs of Oreochromis niloticus and Tilapia zillii. It also deals with the impact of these parasites either on the infected tissues or on the whole biology of the fishes under study. The specimens were collected from three different water bodies; the River Nile, El-Foadia stream and El-Mora canal in Sohag. Were...
Article
The present work aimed to screening and documenting the diversity of scale characteristics of two species belonging to two different genera of the family Sparidae: Acanthopagrus bifasciatus and Rhabdosargus sarba from the Red Sea. The valid useful scale characters for systematic purposes were determined in the term of morphometry and Scanning Elect...
Article
The present study investigated effects of environmental relevant concentrations of 4-nonylphenol (0.05 to 0.08 to 0.1 mg/l) on the reproduction and embryonic developmental stages of catfish (Clarias gariepinus). To determine the effect of 4-nonylphenol on reproduction; catfish were exposed to three concentrations of 4-nonylphenol in a flow-through-...
Article
Scale characteristics and its detailed structure from different body regions were studied in three Plectorhynchus species in terms of morphometry and Scanning Electron Microscopic techniques. The present work has been suggested to the rarity of taxonomic and biological information about the three Plectorhynchus species, P. gaterinus, P. pictus and...
Article
In the present study the protective role of quince leaf extract against the adverse impacts of ultraviolet radiation-A (UVA) on some tissues of Clarias gariepinus (Burchell, 1822) was considered. Fishes were classified into four groups: control, UVR-treated group (for 3days/for 3h/day), UVR-treated group (for 3days/for 3h/day) with adding 10ml of q...
Article
The presence of the genetic toxic chemicals in the aquatic environment increased. This study aimed using the random amplified polymorphic DNA (RAPD-PCR) assay to investigate the genotoxic effects of 4-nonylphenol in adults and embryos of African catfish Clarias gariepinus. After exposure of adults and embryos to sublethel concentrations of 4-nonylp...
Article
Full-text available
The present investigation aimed to determine the tox-icological effects of mercury chloride on biochemical parameters of the widely consumed African catfish, Clarias gariepinus. Adult specimens of Clarias garie-pinus 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...
Article
Global decline in frog populations is thought to indicate environmental damage caused by human activity. Pollution especially chemicals are found to contaminate aquatic ecosystems and their animals including fish and amphibians during their adult life and sensitive stages of development. Nonylphenol ethoxylate (NPE) is one of the most dangerous che...
Article
The adverse impacts of heavy metals on fish liver were evident with great variability among organs and species. The present study deals with the histological changes of the hepatocytes of the Nile tilapia, Oreochromis niloticus, following exposure to 2.5, 5, 10 ppm of lead nitrate for 1, 2, 3, 4 weeks. The present results revealed that lead nitrate...
Conference Paper
Full-text available
The aim of the present investigation is to determine the toxicological effects of mercury chloride on haematological parameters of the widely consumed African catfish, Clarias gariepinus. Adult specimens of Clarias gariepinus were exposed to a sublethal concentrations (0.04 and 0.12 ppm) of mercury chloride for 7, 14, 21 and 28 days. Blood samples...
Article
The present study was carried out to investigate the potential protective effects of tomato paste (9 mg lycopene kg-1 b.wt.) in comparison with vitamin E (50 mg kg-1 b.wt.) against the impacts of cadmium (Cd) toxicity (4.64 mg L-1, 1/4 of 96 h- LC50) Oreochromis niloticus exposed for 15 and 30 days. Cd impacts were evaluated in terms of histopathol...
Article
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 asso...
Article
Alticus kirkii is an air-breathing fish inhabiting the intertidal zone of the Red Sea. The study aimed to determine the role of the skin of this species in air-breathing in terms of histological characteristics of the Epidermis and its Thickness (EPT), blood Capillary Number (CN), Mucous Cell density (MC) and the Diffusion Distances (DD) along ten...
Article
In present work, some biochemical characteristics of the catfish, Clarias gariepinus were studied under the effect of different sublethal doses of 4-nonylphenol (0, 0.05, 0.08 and 0.1 mgl -1). Liver enzymes ALT and AST increased insignificantly at P<0.05 whereas the ALP decreased insignificantly. The activities of G6PDH showed significant increase...
Article
In the present study, the scale characteristics of the three Lutjanus species: L. monostigma, L. ehrenbergi and L. bohar from the Red Sea at Hurghada, Egypt were revealed and taxonomically evaluated in the terms of their morphometry and microstructures using light microscopy and Scanning Electron Microscopy. A wide spectrum of size-free inter-speci...
Article
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 c...
Article
The present study investigates the potential protective effects of tomato paste (9 mg/kg-lycopene) in comparison with vitamin E (50 mg/kg) against the impacts of cadmium (Cd) toxicity (4.64 mg/l: ¼ of 96 h LC50) on fishes Cd exposed for 15 and 30 days. Cd impacts were evaluated in terms of biological, haematological and biochemical characteristics....
Article
In the present work we have described the genotoxic potential of two pathogenic strains of zoosporic fungi (Achlya klebsiana and Aphanomyces laevis) on erythrocytes of Nile tilapia Oreochromis niloticus niloticus for the first time by three complementary tests: micronucleus test (MN), nuclear lesions (NL) and comet assay (CA). The groups exposed to...
Article
Full-text available
Many ultraviolet-A (UVA)-induced biochemical and physiological changes are valid as biomarkers using aquatic species for detection of the degree of stress. Changes in the concentration and activities of enzymes, such as glucose-6-phosphate dehyderogenase (G6PDH), lactate dehyderogenase (LDH), DNA damage and lipid peroxidation (LPO), can be used as...
Article
Increasing lead contamination in Egyptian ecosystems and high lead concentrations in food items have raised concern for human health and stimulated studies on monitoring ecotoxicological impact of lead-caused genotoxicity. In this work, the alkaline comet assay was modified for monitoring DNA strand breakage in sensitive early life stages of the Af...
Article
Embryonic development of Clarias gariepinus was studied from oocyte activation to the end of endogenous feeding (164 h post-fertilization, 164 h-PF). The ontogeny of the eyes, the ear, the heart, the digestive tract and the notochord were described histologically: (i) eyes were not pigmented at hatching (40 h-PF) and the anlage of the retina was ob...
Article
Full-text available
In the present work, heavy metal distribution and the corresponding damage in some organs of Bagrus bajad collected from Assiut, Egypt were studied. The residues of Copper, Zinc, Cadmium, Manganese, Iron and Lead were determined. Variability in such residues among different localities and organs was analyzed reflecting different patterns of distrib...
Article
Full-text available
In the present study heavy metal distribution and the corresponding tissue damage in some organs of Oreochromis niloticus collected from Assiut, Egypt were investigated. The residues of Copper, Zinc, Cadmium, Manganese, Iron and Lead were estimated. Variability in such residues among different localities, sediments and organs was analyzed reflectin...
Article
In the present work, the destructive effects of Ultraviolet-A radiation on the African Catfish, Clarias gariepinus was revealed in terms of total protein, cholesterol, glucose, hemoglobin and erythrocytic indices, differential blood cell counting, heamatocrite, creatinine level, Aspartic Amino Transferase, Alanine Amino Transferase and Alkaline Pho...
Article
The effect of lead exposure (100, 300, and 500 microg/L lead nitrate) on embryos of the African catfish Clarias gariepinus were examined by gross morphology and histopathology. Exposition to lead nitrate caused a progressively longer delay in hatching and also reduced the percentage of embryos, which successfully completely hatch from 75% in the co...
Article
Glucose-6-phosphate dehydrogenase (G6PDH), lactate dehydrogenase (LDH) and pyruvate kinase (PK) are key metabolic enzymes. G6PDH has been used as a biomarker of pollution-induced carcinogenesis in fish. LDH has been used as marker of lesions in toxicology and clinical chemistry, and PK catalyses the conversion of phosphoenol pyruvate to pyruvate, w...
Article
Full-text available
Much of the existing knowledge of the mechanisms involved in teleost fertilisation is based on a few small model species that have no commercial value. Research is therefore urgently required to address mechanisms involved in fertilisation in species of great commercial value. In this study, the ultrastructural morphological variations in the surfa...

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