This research was conducted to measure the safety of heat stable enterotoxin a (STa) produced by enterotoxigenic Escherichia coli, through studying its toxic effect on mice since it showed a promising effect in reducing the proliferation of colorectal cancer cells. The cytogenetic effect was determined after giving five different doses (100, 200, 400, 800 and 1600)μg/Kg in comparison with negative (phosphate buffer saline / PBS) and positive (mitomycin C/ MMC, at doses of 2 and 5μg/Kg) controls on mouse bone marrow cells by employing the following parameters: mitotic index, chromosomal aberrations and micronucleus, also, the serum level of liver functional enzymes (GOT, GPT, ALP) was recorded. In addition, lethal dose 50 (LD 50) with certain clinicopathological changes in five organs (colon, kidney, liver, stomach and lung) was also determined after oral administration of STa for ten successive days and at two doses (500 and 1000) μg/Kg. Results showed that, none of the five different doses of STa caused any significant changes in the three examined cytogenetic parameters in the mouse bone marrow cells; precisely, neither the low dose nor the high one of STa caused reduction or induction in these parameters. In fact, clear effect in decreasing mitotic activity and increasing spontaneous frequencies of both chromosomal aberrations and micronucleus was revealed after MMC treatment. Furthermore, significant differences in mouse serum level of the three enzymes were not seen at any doses of STa, while significant reduction in the levels of these enzymes was noticed after treatment with the two doses of MMC. In this study the LD 50 test was used to investigate the lethal effect of the partially purified STa, and it was shown to be not lethal to mice at both doses of (500 and 1000) μg/Kg, since death was not recorded, moreover, no clinicopathological effects were indicated in the all examined mouse tissues, however the only noticed clinical sign was diarrhea with all doses, which was observed after three days of STa treatment.
A total of (25) stool samples were collected from children and adults (2- 4) years old suffering from diarrhea to isolate E. coli strains that produce heat-stable enterotoxin a (STa), and after performing microscopic examination, cultural characterization and biochemical identification only (11) isolates showed positive E. coli. STa activity was estimated by using suckling mouse assay (SMA) and from these (11) isolates only (5) showed STa activity and the one with the highest STa activity was selected for large scale production of STa, which was followed by partial purification using ion-exchange chromatography (normal phase) using DEAE sephadex A-50 column. After purification and determination of protein concentration by using the standard
... Show MoreThis research was conducted to measure the safety of heat stable enterotoxin a (STa) produced by enterotoxigenic Escherichia coli, through studying its toxic effect on human blood lymphocyte, since it showed a promising effect in reducing the proliferation of colorectal cancer cells. the cytogenetic effects of (STa) by using five different concentrations (100, 200, 400, 800 and 1600μg/ml) in comparison with negative (PBS, Phosphate buffer saline) and positive (MMC, Mitomycin C) at concentration of 5μg/ml, controls on human blood lymphocytes obtained from both (10) normal healthy persons and (20) colorectal cancer patients was measured by employing the following parameters: mitotic index, blast index, chromosomal aberrations and micronucle
... Show MoreThis study was conducted for evaluating the cytotoxic effect of heat stable enterotoxin a (STa) produced by enterotoxigenic Escherichia coli on the proliferation of primary cancer cell cultures, obtained from tumor samples that were collected from (13) cancer patients and as follows: (five colon cancer patients, two bladder cancer patients, two breast cancer patients, two stomach cancer patients and two lung cancer patients), and on normal cell line (rat embryonic fibroblast / REF) (in vitro) with the use of different concentrations starting from (1) mg/ml and ending with (0.0002) mg/ml by making two fold serial dilutions by using the 96- well microtiter plate, and in comparison with negative (PBS) and positive (MMC, at concentration
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Twelve albino mice was divided randomly into four groups comprising A through D injected with ceftazidime at sub MIC, Escherichia.. coli 11, Escherichia.. coli 11 with ceftazidime solution, and standard strain, respectively. Histopathological sections did not show any changes in respect to group A. however, group C suffered signs of infection less than those appeared in group B sections. Simultaneously, group D suffered intense histpathological changes more than other groups infected with resistant isolate.
The present research was carried out to assess the toxic effect of oral administration of the aqueous extract of Nerium oleander leaves and flowers daily at doses of (25) mg/kg body weight for four weeks in mice. The toxicity of this plant parts was determined after two and four weeks by measuring the parameters of cytogenetic (mitotic index, micronucleus %), and serum levels of the hematological (RBC, Hb, WBC) and biochemical (GOT, GPT, ALT, AST) indexes in comparison with that of the control (normal saline), also clinical signs were determined. The results showed a significant decrease in mitotic index while an obvious raise was seen in micronucleus percentage in comparison with that of the control after the two periods of admini
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Some Factors determining the virulence of Escherichia coli ( E. coli ) isolates were studied ,of 25 isolates , 17(group A) uropathogenic E. coli ,6 (group B) infected gastrointestinal tract , 2 (group C) infected wound , beside these group we use the standard strain E. coli HB101 as control group. The twenty five isolates were tested for adherence capability to human buccal cavity epithelial cells by in vitro experiment . The results showed that all isolates have different adhesion capability with mean ranging from (14.35±11.39) to (33.80 ± 22.68) bacteria / epithelial cell It was noticed that isolates EU9, ES6, EW17 displayed high adhesive capability with mean value (33.80 ± 22.68), (32.60 ± 21.19), (29.90±22.50) bacteria /epithelial
... Show MoreAcute toxicity is a step to evaluate the toxicity of a substance. Rutin is one of the flavonoid compounds with a variety of pharmacological effects. The aim of the study is to calculate the lethal dose that affect fifty percent of the mice used in the experiment (LD50). Thirty Swiss albino male and 30 non-pregnant female mice have been divided equally and randomly into 5 treated groups and one control group (n=5) Rutin has been administered with concentrations 5, 2.5.1.25,0.625 and 0.312 g/kg administered as a single dose intraperitoneally (IP) while the control group received 1% DMSO (IP). Animals were observed for any morbidity and mortality for 14 days. After 14 days the animal blood collected for biochemical and hem
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Proteases have various applications in the food, pharmaceutical, medicine, pathogenicity of some pathogenic bacteria, and detergent sectors as well as meeting the needs of approximately 60% of the global enzyme industry, whereas they catalyze the breakdown of protein molecules into peptides and amino acids. Production and purification of protease enzyme by the isolate Escherichia coli AJ55 was scrutinized in the present study. Cultivation optimum conditions, were various complex medium, carbon source, nitrogen source, temperature, pH of the medium, and time of incubation were optimized to enhance the total protease production in shake flask culture of E.coli AJ55. The nutrient broth supplemented with 2% gluco
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