This study has been performed to study the inhibitory effects of crude plant extracts of Bay (laurus nobilis) leaves against some bacterial isolates represented by Staphylococcus aureus, Staphylococcus epidermids, Proteus vulgaris, Bacillus subtilis, Escherichia coli, and Pseudomonas aeroginosa in vitro. The results showed that percentages of essential chemical of laurus nobilis leaves which represented by moisture, total oil, total ash, crude protein, crude fibers, carbohydrites and caloric values in dry weight are 5.96, 4.28, 14.2, 8.75, 24.8, 76.99%, and 284.92 kcal/100g respectively, the percentages of some major and minor mineral elements of laurus nobilis leaves powder which represented by Mg, Fe, Cu, Pb, Cd and As, are: 0.211, 0.165, 0.023, 0.011, 0.00, 0.0004 mg/g and 3.140 ppm, respectively, while Co did not appear in the laurus nobilis leaves. The aqueous extract of the plant was acidic its pH 5.79. The results of initial detection (precipitation) showed that ethyl acetate and aqueous extracts of laurus nobilis leaves contain all active compounds represented by tannins, saponins, flavonoides, glycosides, phenols, terpenoids, sterols and cumarin, while alcoholic and hexan extracts contain also the some compounds except saponins, hexane extracts no phenols. Through the study of the effect of laurus nobilis leaves extracts against growth of bacteria in vitro a significant differences at (p<0.05) was observed, It was found that the ethyl acetate and alcoholic extracts more were effective on the bacterial species than the other remaining extracts against the growth of bacteria, inhibitory activity was of all bacterial species at concentration of 3.125mg/ml and it was more effective on Staphyloccocus epidermids for ethyl acetate extract giving inhibitory zone estimated 15.5mm, while alchoholic extract was activity against bacteria E. coli at inhibition zone estimated 15mm, while hexan extracts has been showed inhibition activity of same concentration only on bacteria Staphyloccocus aureus with zone 10.5mm, as for it has been showed inhibitory activity of bacteria Proteus vulgaris at concentration 12.5mg/ml with zone 13mm, as for Staphyloccocus epidermids, Bacillus subtilis, E. coli and Pseudomonas aeroginosa were their inhibition activity at concentration 25mg/ml while Staphyloccocus aureus was highest inhibition at zone 16.5mm and 14mm of same concentration as for the hexan and aqueous extracts respectively, while the inhibition of bacteria Proteus vulgaris was zone 10mm of aqueous extract, inhibitory activity of bacteria Pseudomonas aeroginosa has been showed at concentration 50mg/ml of zone 16mm, as for the bacteria Staphyloccocus epidermids, Bacillus subtilis were the inhibitory zone at 12mm and E. coli at zone 18mm of concentration 100mg/ml. When measuring the minimum inhibitory concentration (MIC) for each bacterial species at a concentrations 6.25- 12.5mg/ml for ethyl acetate and alcoholic extracts have high inhibitory activity compared with the other concentrations, but the hexane and aqueous extracts have affected bacterial species at 12.5- 100 mg/ml, except for Staphyloccocus aureus and Bacillus subtilis, which was not affected by any of the concentrations of extracts.
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The study included the collection of samples of raw cow milk to isolate Leuconostoc bacteria, samples were sub cultured on De-Man Rogosa Sharpe-Vancomycin medium, the pure colonies were selected and subjected to the cultural and microscopically tests, according to that 25 cocci bacterial isolates were obtained, then isolates were subjected to biochemical tests. Result of tests showed that 12 isolates belong to the genus Leuconostoc out of 25 cocci bacterial isolates, Vitek2 system was used as a supplementary step. Results of final identification showed that 3 sub species were obtained included Leuconostoc mesenteroides ssp. cremoris 9 out of 12 isolates, while it was 2 isolates of Leuconostoc mesenteroides ssp. mesenteroides and one isol
... Show MoreIn this study, functional and numerical response tests, which are important components in the selection of biological control agent, were carried out. In functional response trials, the amount of food consumed, attack rate (a) and handling time (Th) were calculated for each developmental period, depending on the number of preys given after 24 hours. The obtained results were evaluated with the Holling. In numerical response experiments, the development of the predator insect was examined depending on the number of preys given in certain numbers (5, 10, 20, 40 and 80) and the data were recorded. This phase of the trials continued until the individuals died. At this stage of the trials, the reproductive response of the p
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Seeds of the two rice genotypes namely Amber 33 (A33) and Amber Baghdad (AB) were divided into two groups; the first was presoaked in different concentrations of ethyl methane sulphonate (EMS) as chemical mutagen for different duration times (3, 6 and 12) hrs, and the other was exposed to different exposure times of ultra violate (UV-B) radiation (280-320 nm) as physical mutagen for different times (20, 40 and 60) min at room temperature. Treated and non-treated seeds were transferred into the callus induction medium containing 2.5 mg/L 2,4- dichlorophenoxy acetic acid (2,4-D) and 0.5 mg/L benzyl adenine (BA) under aseptic conditions. Calli were divided into two groups the first was treated with several EMS concentrations (0.0, 0.50. 1.0, 1
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