Egyptian Toad Research Articles

The Egyptian Toad (Bufo regularis Reuss) as bioindicator to environmental deterioration with heavy metal in El-Behera governorate

The Egyptian Toad (Bufo regularis Reuss) as bioindicator to environmental deterioration with heavy metal in El-Behera governorate

Impact of atrazine and nitrate on liver and kidney of egyptian toad Sclerophrys regularis: bioindicator alarming on ecosystem

Atrazine and nitrate have been shown to act as potent oxidative stressors in amphibians either alone or in combination under stable laboratory conditions, causing histopathological alternations in liver and kidney structures at the sub-lethal concentrations. A control group and three treatments groups were tested; atrazine, nitrate, atrazine-nitrate treatments with doses of 300 μg L-1, 200 mg L-1 and their combination respectively. Sever distortion in liver and kidney tissues were shown related to the different treatments. The most hepatic lesions were observed depletion in glycogen content, degeneration of hepatocytes, hemorrhage, necrosis, vasodilatation, congestion in blood vessels, cloudy swelling in the hepatocytes and aggregation of melanomacrophage cells in between the hepatocytes that increased in combination treatment group. In kidney, the most lesions were represented in degeneration of renal tubules, fibrosis, hemorrhage, leucocytes infiltration, thickness in the wall of the renal capsule, atrophy of glomerulus, deformation of Bowman’s epithelium. These negative impacts may be a bioindicator alarming the ecosystem disrupting caused by the uncontrolled apply of these chemicals in agriculture.

Biochemical and genotoxic effects of some pesticides on the Egyptian Toads, Sclerophrys regularis (Reuss, 1833)

The effect of the 1/10 the application rates of either copper sulfate, temephos, glyphosate, or bifenthrin on some biochemical and genotoxic markers of the Egyptian toads, Sclerophrys regularis, exposed for 96 hours under conditions similar to the real situation was investigated. The results illustrated that , brain acetylcholinesterase (AChE) was significantly inhibited following temephos treatment, while the enzyme activities markedly increased following either glyphosate or bifenthrin exposure. Liver glutathione-S-transferase (GST) activity was inhibited following either copper sulfate or bifenthrin, while the activity increased following glyphosate treatment. Also, the data illustrated that, The level of glutathione reduced (GSH) in liver and the activities of lactic dehydrogenase (LDH), transaminasaes (AST and ALT), and phosphatases (ACP and ALP) in liver and serum showed significant increases following all the treatments and bifenthrin was the potent one. Regarding the genotoxicity of the tested pesticides, the number of structural aberrations induced by the different treatments was enumerated in the present study. It was found that all the tested pesticides significantly increased either the frequency of abnormalities or the number of polychromatic erythrocytes (PCE) per 1000 cells (the frequency of micronucleus, MN) compared to the negative control, where bifenthrin and temephos were found to be more potent than cyclophosphamide (positive control) to induce these structural aberrations. According to the present results, the tested concentrations of the tested pesticides could lead to a collapse of cellular homeostasis and changes in the biochemical and genetic parameters in the Egyptian toads which can be considered as indicators of environmental pollution by pesticides.

Effect of induced sublethal intoxication with neonicotinoid insecticides on Egyptian toads (Sclerophrys regularis).

The toxicity role of insecticides affecting nontarget vertebrate of wildlife population has become essential subject to focus on. In this vein, the current study aimed to illustrate some biochemical and histopathological alterations induced by two neonicotinoids in Egyptian toads. Forty-five toads were collected and divided equally into three groups (15 toads/group): control group, thiamethoxam group, and acetamiprid group. Both treatment groups received thiamethoxam and acetamiprid (30 and 40 mg/L, respectively) four times within 12 days for induction of sublethal toxicity. Blood and liver tissue samples were collected. Both insecticides cause the same changes, but acetamiprid group exhibited a pronounced significant (P ≥ 0.001) effect than thiamethoxam group on increasing serum lipid profile, ALT, and AST. Moreover, acetamiprid showed a significant (P ≥ 0.001) decrease in hepatic total protein, GSH, and SOD and increase in MDA levels in comparison with thiamethoxam and control groups, respectively. The histopathological hepatic examination showed markable alterations in hepatic architecture in treatment groups that was distinct in acetamiprid group. Finally, our findings illustrate the indirect effect of neonicotinoids on toads and may realize their life-threatening factors. Graphical Abstract.

Genotoxicity and limbs asymmetry in the Egyptian toad (Sclerophrys regularis) as biomarkers for heavy metals toxicity

Genotoxicity and limbs asymmetry in the Egyptian toad (Sclerophrys regularis) as biomarkers for heavy metals toxicity

The Efficiency of Sclerophrys regularis as a Bioindicator

Many populations of amphibians are facing remarkable decline throughout the world. The reason for the decline is a direct response to habitat destruction and pollution including heavy metals. The blood of the toad is vascular and very plastic tissue. In fact, a variation of several hematological parameters in response to natural changes in the environment has been widely described previously. Since hematological parameters are influenced by a variety of environmental stressors, they have the potential to be used as biomarkers of aquatic pollution. Heavy metals are difficult to remove from the environment and cannot be degraded biologically. The current study assessed the impact of some heavy metals on hematological and serological parameters in the Egyptian toad (Sclerophrys regularis) from two different localities (North Giza and El Wahat regions). The current results have revealed a reduction in the means of RBCs, hemoglobin, and hematocrit values in addition to a remarkable increase in WBCs. In addition, the major serological parameters including protein, albumin, AST, and ALT were also altered in parallel with the deterioration that occurred between the two investigated regions. The present findings have revealed and confirmed that the Abu Rawash area is more impacted compared to El Bawiti.

The biodistribution of melanomacrophages and reactivity of PEG or amine-functionalized iron oxide nanoclusters in the liver and spleen of Egyptian toad after intraperitoneal or oral injections: Histochemical study

Recently, toad flesh is the main source of protein for many peoples. Of note, disease treatment of amphibian animals is a big challenge facing toad farms development. Iron oxide nanoclusters (IONCs) are approved by the Food and Drug Administration (FDA) as new materials for drug delivery systems development. The biodistribution and fate of IONCs in the lower vertebrate tissues such as toads is novel and should be studied in details. In this study, the biodistribution and toxicities of polyethylene glycol-functionalized IONCs (PEG-IONCs) and amine-functionalized IONCs (NH2-IONCs) in the liver and spleen of Egyptian toad were studied after intraperitoneal or oral injections. The localization and levels of IONCs in liver and spleen depends on the root of injection and the surface functionalization. The presence of IONCs in the liver and spleen produced sever to mild histological and histochemical abnormalities, but in a different ratio. The change of melanomacrophages (MMs) numbers depends on the root of injection or the function group on the surface of IONCs and this explains the abnormalities of MMs produced by IONCs treatment. Further, the function group on the surface may control the biodistribution of MMs and abnormalities produced by IONCs in the liver and spleen. Understanding the biodistribution and histological abnormalities of IONCs in the lower vertebrate tissues (amphibians in this study) might introduce important information to develop new drugs which can be used for amphibian diseases treatment or diagnosis. Further, the histopathological and MMs abnormalities produced by IONCs may consider as biomarkers for amphibians diseases diagnosis.

First light microscopy and ultrastructural description of Mesocoelium sociale (Luhe, 1901) Odhner, 1910 (Trematoda: Mesocoeliidae) in Bufo regularis from Egypt

BackgroundMesocoeliidae is a common parasite of the small intestine of amphibians and reptiles. From Egypt, only Mesocoelium monas (Rudolphi C., Berolini 811 (1819)) (Freitas JF, Revista Brasiliera de Biologia 18:171-174, (1958)) was reported and described by (Saad AI et. al., J Egypt Ger Soc Zool 33: 219-234, (2000)) from the small intestine of the Egyptian toads Bufo regularis from Aswan Governorate, Upper Egypt, and the molecular characterization of the same parasite was reported by (Mansour MFA et. al., Egypt. J. Biol. (Zool.),10:(1)1-8, (2014)) without any morphological description from the same final host. The present study aimed to detect the prevalence and the characteristic morphological features of mesocoeliid parasites of the Egyptian toads Bufo regularis.MethodsToads were collected from Assiut and Giza Governorates during the autumn of 2018. They were dissected and examined by a dissecting microscope for intestinal parasites. The collected trematodes were fixed, stained, dehydrated, cleared, and mounted. Photomicrographs were taken and parasite measurements were determined. Some of the identified worms were prepared for scanning electron microscope for studying their ultrastructure.ResultsMesocoelium sociale was detected from the small intestine of 14 out of 51 toads Bufo regularis (27.5%) with worm burden (10–30 worms per host). Detailed morphometric characteristic features of the parasite were described by a light microscope. Scanning electron microscopy showed many fine ultrastructure details in the present study and confirmed the light microscopic description.ConclusionMesocoelium sociale (Luhe M, Centralblatt für Bakteriologie Parasitenkunde und Infektionsk-rankheiten, 30, 166-177, (1901)) (Odhner T., Res. Swedish Zool Exped Egypt iv, (23a), 1–166, (1910)) is recorded for the first time from Egypt as a trematode parasite of the Egyptian toads’ Bufo regularis and described by a light microscope. In addition, it is described for the first time worldwide by scanning electron microscopy.

The Egyptian Toad, Sclerophrys regularis (Reuss, 1833) at Sharm El-Sheikh, with Comments on Amphibians of the Sinai Peninsula

The Egyptian toad, Sclerophrys regularis (Reuss, 1833) was observed in the palm grove in «Old town» of Sharm el-Sheikh, the southern tip of the Sinai Peninsula, in September 2014. Local population consisted of numerous animals of different ages (with body sizes ranged from 2 – 3 to 6 – 7 cm). This is a new case of the introduction of amphibians to Sinai. All previously published Sinaitic records of five amphibian species are discussed in terms of taxonomy, distribution and zoogeographic affinity. Two sources of invasions, from the east (Gaza Strip and Israel) and from the west (Nile Valley), are considered.

Retina damage after exposure to UVA radiation on the early developmental stages of the Egyptian toad Bufo regularis Reuss

The present study was carried out to investigate the histological and histochemical changes in the retina on different developmental stages of Egyptian toad Bufo regularis. Our experiment started when tadpoles begin to feed. The adapted embryos are divided into 3 large tanks of 200 embryos each, collections of samples started from feeding age every three days. Both histological and histochemical results showed that the general architecture of the retina organ is correlated with the state of development. Therefore, it displayed different characteristic features depending on the investigated developmental stage starting from the larval stage (feeding began, stage 44) and ending with the post-metamorphic stage 66. Also, the present work aimed to study the chronic effects of UVA on the retina structure of B. regularis during development and metamorphosis for the first time.

Hepatic Alteration of the Egyptian Toad Amietophrynus Regularis, as Biomarker to Environmental Deterioration

Based on available toxicological studies dealt with aquatic fauna in Egypt, none of these studies considered terrestrial stage of amphibian exposure and uptake of metal from surroundings habitat. Little is known about how contaminants affect amphibians at the population level. Three sites were selected scarily in order to comprise different types and sources of pollutants from one hand, and to prove the potential of selected animals to accumulate pollutants. The common Egyptian toad Amietophrynus Regularis was collected from different localities along the river Nile. The aim of our study was to evaluate the biochemical and histopathological biomarkers in this specie to a pollution gradient caused by domestic discharges and heavy metals and to verify the adequacy of the studied animals as appropriate bioindicator in their habitat. The results of this study revealed that deterioration of natural habitat of the selected amphibian produced manifested biochemical and histopathological changes in the liver.

Hematotoxic and biochemical effects of UVA on the Egyptian toad (Bufo regularis)

Purpose: To study the adverse impacts of ultraviolet radiation-A (UVA 320–400 nm) on some hematological and biochemical parameters of Bufo regularis was considered.Materials and methods: Samples were classified into four groups: (i) Control; (ii) ultraviolet radiation (UVR)-treated group (for 3 days/for 15 min/day); (iii) UVR-treated group (for 3 days/for 30 min/day); and (iv) (for 3 days/for 60 min/day). The destructive effects of UVA radiation was evaluated by red blood cells (RBC) count, hemoglobin content (Hb), hematocrite (Ht), erythrocytic indices, white blood cells (WBC) count, total protein, glucose, aspartic amino transferase (AST), alanine amino transferase (ALT), alkaline phosphatase (ALP), lactate dehyderogenase (LDH), glucose-6-phosphate dehyderogenase (G6PDH) and total bilribuin.Results: No mortality was observed. However, some physiological effects after the exposure to UVA were reported. The UVA-induced malformations recorded in the red blood cells included crenated cells (Cr), Acanthocytes (Ac), tear drop-like cells (Tr) and sickle cells (Sk).Conclusion: The present study revealed the exposure to UVA from 15–60 min/day for three days could promote several biochemical and physiological disturbances as well as some changes in RBC.

Histological and Histochemical Studies on the Early Developmental Stages of the Egyptian Toad <i>Bufo regularis</i> Reuss

The present study was carried out to investigate the histological and histochemical changes in the liver and skin on different developmental stages of Egyptian toad Bufo regularis to be used as a histological key for such species. Our experiment started when tadpoles began to feed. The adapted embryos are divided into 3 large tanks of 200 embryos each, collections of samples started from feeding age every three days. Both histological and histochemical results showed that the general architecture of the different organs was correlated with the state of development, i.e. larval, met-amorphic and post-metamorphic. They, therefore, displayed different characteristic features de-pending on the investigated developmental stage starting from the larval stage (stage 44) and ending with the post-metamorphic stage 66.

Molecular Characterization on the Early Developmental Stages of the Egyptian Toad <i>Bufo regularis</i> Reuss

The present study aimed to investigate changes in the protein contents using SDS-PAGE, also using the random amplified polymorphic DNA (RAPD-PCR) assay to identify changes in DNA concentration in the embryos of Egyptian toad Bufo regularis. Our experiment started when tadpoles began to feed. The adapted embryos were divided into 3 large tanks of 200 embryos each, collections of samples started from feeding age every three days. Cluster method was used to indicate the distinct distance between the band patterns of different stages. An increase occurred in the concentration of protein fractions in these tadpoles upon metamorphosis and that when metamorphosis was completed. DNA concentration exhibited an evident low values at the premetamorphic stage 44 (105.85 ± 0.519 ng/μl) compared with the other more advanced developmental stages 55 and 56 (204.056 ± 0.651 ng/μl and 234.55 ± 2.325 ng/μl respectively). In conclusion, acquire information about the changes in the molecular content of Bufo regularis during metamorphosis has been estimated.

Effect of gibberellin-A3 on metamorphosis in the Egyptian toad Bufo regularis

The present study was carried out to study the effect of gibberellin-A3 on the metamorphosis of the Egyptian toad Bufo regularis. Samples of B. regularis were collected from Shebin El-Kom, Menoufia Governorate during the breeding season and kept in aquaria with little water till spawning, fertilized eggs are divided into 2 groups of 200 eggs each. The 1st group was treated with 5ppm of gibberellin-A3 (Berelex) 3days/week for the period of metamorphosis. The second group was left untreated under the same environmental conditions and considered as a control. Hatchability of the eggs in each group was recorded. External lengths of the total body, hind limbs and the tail were measured. As a measure of apoptotic DNA fragmentation, the presence of DNA ladder was determined. The results showed that out of 200 eggs 47.5% were hatched in the control group and 76.5% were hatched in gibberellin-A3 treated group. The average duration of metamorphosis was 60days and 52days in the control and treated groups, respectively. There was an increase in the total length of the hind limbs of the treated tadpole as compared with the control throughout the experimental periods. DNA isolated from control and tadpoles treated with gibberellin-A3 showed degradation into oligonucleotide fragments forming a clear laddering pattern of apoptosis, but the treated tadpoles showed an increase of DNA fragmentation.

Application of premetamorphic oral cavity electron micrographs for Egyptian toads’ taxonomy

In the present study, the microanatomy of both the oral disc and buccal cavity of the tadpole of Bufo regularis was described. Tadpoles of 32, 38 and 40 stages were dissected and analyzed using scanning electron microscope. In all the stages, the mouth was ventral and the oral disk width was large, that is, equal to about 44% of the greatest width of the body. The disk was provided with a broad gap on the lower lip; the rest of the mouth was bordered by a large number of papillae. The papillae were arranged in a single row on the dorsolateral part of the mouth; the ventrolateral and ventral lip was surrounded by a double row of papillae. The number of papillae increased with larvae growth, from zero in stage 32 to about 150 in stage 40. The tooth row formula is 2(1)/3(2). The upper and lower beaks were pigmented and serrated. While the upper beak was broadly arched and formed a smooth arc, the lower beak had V-shape. Premetamorphic papillae were observed during the early metamorphic stages, and these degenerated rapidly at about late metamorphic stage. Metamorphic atrophy of the oral structures occurred roughly in the reverse order of development, although the procedure was rapid and more haphazard than the development. We suggested that the oral flaps and the roof papillae play a significant role in the capture of food particles by establishing the inflow of alimentary water, and aggregating food particles and mucus inside the buccopharyngeal cavity, which may reflect ecological and functional constraints that are relative to the morphology of other suspension feeding anuran larvae. Herein, we described the oral features of the tadpoles of B. regularis. Key words: Anuran tadpoles, scanning electron microscope, oral disc, oral papillae, jaws, gap.

Chloromyxum aegypticus n. sp. (Myxozoa: Chloromyxidae) infecting the testicular tissue of the Egyptian toad, Bufo regularis (Amphibia: Bufonidae), and its pathogenicity

A new myxosporean, Chloromyxum aegypticus n. sp., is described from the testes of the Egyptian toad Bufo regularis, captured from El Mansoura locality. C. aegypticus is identified on the basis of cytology, electron microscopy and histopathology. It is distinguished from all previously reported Chloromyxum spp. by its shape, dimensions of the mature spore (9.1 ± 0.1 (9.0-9.2) μm in length × 7.9 ± 0.1 (7.8-8.0) μm in width), polar capsules, external ridge, sporoplasm nuclei, undulating suture, locality and host. Accumulation of several hundreds of plasmodia (0.8 ± 0.3 (0.5-1.1) mm in length × 0.5 ± 0.3 (0.2-0.7) mm in width) in the testes causes their enlargement. Parasites cause destruction of the seminiferous tubule cells and complete loss of spermatozoa. Since spermatogenesis stops, this seems to be a form of "parasitic castration". This is the first known record of the genus Chloromyxum in amphibian testes.

Comparative changes in absorption, distribution and toxicity of copper and cadmium chloride in toads during the hibernation and the role of vitamin C against their toxicity

The aim of this study was to determine the bioavailability and adverse effects of cadmium (Cd) and copper (Cu) on hibernating Egyptian toads and whether ascorbic acid (vitamin C) blocked Cd- and Cu-induced effects during hibernation. The oxidative status of liver, kidney, and intestine of Bufo regularis to Cd, Cu, and/or a combination of both metals administered orally for 2 weeks was determined. In the protection studies, vitamin C was given for 1 h prior to administration of Cu, Cd, and/or metal combination for 2 weeks. Treatment with Cu, Cd, and a combination of both metals produced a reduction in red blood count cells and hemoglobin content, while white blood count cells showed an increase in numbers during these treatments. After 2 weeks exposure, Cd and Cu increased significantly in all the tissues studied. Cu storage presented the following sequence: liver > intestine > kidney. Cd storage presented the following sequence: intestine > kidney > liver. When exposed to both metals, Cu and Cd storage presented the following sequence: liver > intestine > kidney. Histopathological examination of the liver revealed marked alterations including loss of hepatic cell architecture, and some cells exhibited distinct cytoplasmic vacuoles. The majority of blood vessels exhibited a marked dilatation and congestion with infiltration of blood cells, prominent hyperemia of hepatic veins, and significant proliferation of bile ductules. Histopathological changes in the kidney showed destruction and degeneration of both renal tubule cells and glomerular with infiltration of leukocytes and inflammatory cells. Histopathological alterations in the intestine were restricted to the innermost mucosal epithelium with marked degeneration of the villi and submucosa and an extensive fragmentation of mucosal epithelium as well as atrophy of goblet cells. The administration of vitamin C 1 h prior to administration of Cd, Cu, and metal combination did not protect against hepatic, renal, and intestinal damage. However, parental vitamin C given alone increased tissue toxicity.

Induction of leukaemia in chloramphenicol-treated toads

Chloramphenicol has been associated with the development of aplastic anaemia. As it is still widely used in Egypt, we studied its effect on 100 Egyptian toads (Bufo regularis) given a dose of chloramphenicol of 5 mg/40 g body weight for 12 weeks. We found it induced numerous, severe ultrastructural changes in almost all types of leukocytes. These changes were similar to those induced by the chemical carcinogen 7,12-dimethylbenz(a)anthracene in 100 toads used as the carcinogen control group, and similar to those in leukocytes reported in humans with leukaemia. We recommend regulations be applied on the use of this antibiotic in countries where it is still widely used.

Effect of Acute Zinc Administration on Essential Metal Levels in Liver, Kidney, Lung and Heart of the Male Egyptian Toad Bufo Regularis

Effect of Acute Zinc Administration on Essential Metal Levels in Liver, Kidney, Lung and Heart of the Male Egyptian Toad Bufo Regularis