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Resultados 1101-1110 de 1,442
OPTIMIZATION OF A CULTURE MEDIUM FOR BIOMASS AND δ-ENDOTOXIN PRODUCTION BY A RECOMBINANT ESCHERICHIA COLI STRAIN
2008
Rawia F. Gamal | Al-Fateh R. | Abeer Mohammed | M. El-Sawy
A recombinant strain of Escherichia coli harboring a plasmid containing the Bacillus thuringiensis δ-endotoxin synthesis gene, was tested for its efficacy to synthesize δ-endotoxin, in a complex medium containing sucrose and yeast extract. Also, the recombinant E. coli strain was tested for its efficacy against the 2nd instars of Spodoptera littoralis. The recombinant strain of E. coli showed a good activity against the 2nd instars of S. littoralis, the mortality was 70 % after 7 days at room temperature. A high cell biomass (8.8gL-1) and δ-endotoxin concentration (6.8 mg L-1), were obtained by the shake flask culture (100 ml medium/250 ml flask, at 200 rpm), of the recombinant E. coli in modified MR medium containing sucrose (20g/L), as carbon source and yeast extract as nitrogen source, in the presence of CaCO3, K2HPO4, MgSO4, FeSO4 and ZnSO4 as mineral salts. The best pH values for cell biomass production and endotoxin production were 7.0 and 7.5, respectively. The corresponding figures for the best temperature were 37oC and 30oC, respectively. The use of some byproducts such as black-strap molasses, corn-steep liquor and cheese whey, as an alternative for carbon and nitrogen sources of medium, were found to enhance the cell growth but showed no effect on endotoxin production.
Mostrar más [+] Menos [-]PRELIMINARY STUDIES ON THE EFFECT OF FOLIAR APPLICATION OF METHANOL AND PINK PIGMENTED FACULTATIVE METHELOTROPHIC BACTERIA ON COTTON PLANT
2008
A pot experiment was carried out in summer season of 2006 to evaluate the different concentrations effect of foliar application of methanol and pink pigmented facultative methelotrophic bacteria (PPFM) on some growth parameters and yield of cotton plant. Data showed that, the highest growth rate value was obtained with PPFM isolates from wheat with 1% methanol. The growth rate of PPFM isolates decreased with increasing the methanol concentration. Foliar applications with 20% methanol with PPFM 3 or 4 spraying times gave the significantly highest values of cotton growth and yield parameters. Such two potent treatments increased leaf area index (LAI) by 51.4 and 55.8 %; number of fruiting branches / plant by 53.1 and 58.0 %; number of total bolls / plant by 38.1 and 43.0 %; seed cotton weight / boll by 37.1 and 48.2 % and seed cotton yield / plant by 46.1 and 50.8, respectively than the control.
Mostrar más [+] Menos [-]INDUCTION OF RESIISTANCE IN TOMATO PLANTS AGAINST ROOT-KNOT NEMATODE BY SOME CHEMICAL AND PLANTS EXTRACTS(a)
2007
Mostafa M | E Gado | M Youssef
Different agents were tested as inducing re-sistance factors in tomato plants against root-knot nematode Meloidogyne incognita. These agents include ethyl salicylic acid, (0.125 ml/l) jassmonic acid (0.125 ml/L) sincocin solution, (0.1%) agrispon solution (0.1%) water extract of mango malformed inflorescence (7.5%), coconut milk solution (2%) as root dipping during transplanting and spraying after one month from transplanting. Data obtained clearly indicated that sincocin solu-tion, extract of mango malformed inflorescence, agrispon solution and jassmonic acid led to a great reduction in disease severity, number of galls/ root, number of females/ root and number of egg masses/ root, followed by ethyl salicylic acid and coconut milk descending order. All tested agents did not affect juvenile's viability except mango malformed inflorescence extract and coco-nut milk solution which led to slight effect on juvenile viability. All tested agents increased plant growth in the presence of nematode inocula in comparison to untreated plants. In this respect coconut milk solution had the superior effect. Data indicated that the tested agents induced resistance in treated plant and the mechanisms of their mode of action needs further studies.
Mostrar más [+] Menos [-]UTILIZATION OF ROSEMARY AND SAGE ESSENTIAL OILS IN THE IMPROVEMENT OF THE QUALITY OF CAKE AS ANTIMICROBIAL DURING HANDLING AND STORAGE
2007
S El-Gohery | Hanan Ahmed | Hala Sayed | Iman Ismail
In this study, the essential oils of rosemary and sage were used to improve cake by two methods either addition or spraying at different concentra-tion on cup cake after 30 min. from baking. The components of essential oils were identified using Gas Chromatography (GC). These oils were eval-uated for inhibitory effect against some pathogenic bacteria especially that may contaminate cake dur-ing handling and storage periods. The effect of these oils at different levels and methods on the sensory characteristics of the produced cake was studied. The results showed that the addition of essential oil of rosemary or sage to cake formula at 1% level increased the acceptability of cakes. While when the rosemary or sage oil sprayed on the cup cake crust after 30 min. of baking at 0.06% or 0.18% level, resulted in a higher over all acceptability scores compared with the other lev-els and cake control. During the storage periods of cakes, using 1.5 % level of rosemary or 0.5% of sage oil added to the formula level resulted in a good acceptability after four and two weeks re-spectively, of storage periods. By using 0.06% concentrations of sage oil sprayed on cup cake crust after 30 min. of baking, the cake had accept-ed during the four weeks of storage periods. Mold growth appeared after 19 and 28 days due to addi-tion of 1% either rosemary or sage oils to the cake formula Meanwhile, the essential oils sprayed at level of 0.12 % of both, the mold appeared after 29 and 33 days for rosemary and sage respective-ly. Also by using the essential oils of rosemary or sage as spray on cake layers, most of bacterial strains and mold-yeast were not detected during the storage periods of cake at room temperature (25 – 30oC). The inhibition of growth of Salmonel-la and E-Coli was noted at 30 μl /disk of rosemary oil and 40 μl /disk for inhibition growth of Bacil-lus Cereus. While the inhibition growth of Salmo-nella, Staph aureus and E-Coli were observed at 40μl /disk of sage oil and at 50 μl/ disk for inhibi-tion growth of Bacillus Cereus.
Mostrar más [+] Menos [-]RAPID ESTIMATIONS OF BIOLOGICAL FINENESS OF COTTON FIBERS USING MICROMAT DATA
2007
A Mohamed | M Sief | S El-Hariry
Rapid estimations of diameter minus lumen(D-L), and outer perimeter of cotton fibers (P) inmicrons, as a biological fineness of Egyptian cottoncould be calculated with satisfactory levels ofaccuracy from hair weight (H.W) in m/tex andmaturity ratio )MR) obtained from Micromat data(new F/MT instrument), using the following equations:2Circularity x 3.14 x 1.52Hs (Standard finenessDiameter (microns) or Final format (D) (microns) = 1.205 HsorCircularit y × 1.524 x 3.14 x HsPerimeter (microns) or Final format (P) (microns) = 3.7853 HsResults of the current study suggested thatmore attention should be focused on meaning andmeasurements of the three values of biologicalfineness (i.e.) diameter (D), perimeter (P) (microns)and standard fineness (Hs) m/tex. whichcan be derived from the data obtained from Micromatinstrument.
Mostrar más [+] Menos [-]EFFECT OF NITROGEN FERTIGATION LEVELS AND CHELATED CAL-CIUM FOLIAR APPLICATION ON THE PRODUCTIVITY OF SWEET CORN
2007
A Abou El-Yazied | M Ragab | Rawia Ibrahim | S Abou El-Wafa
This study was conducted in a sandy soil at Ali Mubarak Village Research Farm, South Tahrir Horticulture Research Station, Behaira Gover-norate, during the two successive seasons of 2002/2003 and 2003/2004 on sweet corn Jubilee hybrid. The study aimed to determine the best treatments of nitrogen fertigation level and chelat-ed calcium foliar application on the productivity and quality of sweet corn. The obtained results indicated that increasing nitrogen fertigation level (100, 120, 140 to 160) kg N/fed. and (or) chelated calcium (12% Ca++) concentration (500 and 1000 ppm Ca EDTA) led to increasing the vegetative growth (leaf area, plant height, fresh and dry weight), chemical composition (total chlorophyll, nitrogen, phosphorus, potassium and calcium in leaves) and yield characters (ear length, ear diame-ter, weight of 1000 seed, unhusked ear, husked ear and total yield) The promising treatment was 160 kg N/Fed. combined with 1000 ppm Ca EDTA under similar prevailing conditions of the present studying in a sandy soil
Mostrar más [+] Menos [-]IMPROVING KEEPING QUALITY OF BUTTER BY UTILIZING MAILLARD REACTION PRODUCTS FROM HEATED WHEY
2007
Mona Abd El-Gawad
The antioxidaitve activity of Maillard reaction products MRPs) from heated whey added to butter was investigated. The antioxidant efficiency changed with different concentrations of MRPs used during storage period at 45ºC. Peroxide val-ue, thiobarbituric acid, acid value, carbonyl com-pounds and free fatty acids of butter were in-creased with storage. Their rate of increase de-creased with increasing the added amount of MRPs to butter.
Mostrar más [+] Menos [-]RESPONSE OF RUTA GRAVEOLENS L. TO ROCK PHOSPHATE AND /OR FELDSPAR UNDER BIOLOGICAL FERTILIZERS
2007
Khalid Khalid | Soheir EL-Sherbeny | A Shafei
Two experiments were consummated at the Experimental Farm, National Research Center (NRC), Dokki, Cairo, Egypt during two succes-sive seasons of 2004/2005 and 2005/2006 to eval-uate the effect of natural products as a source of some important elements such as rock phosphate as a source of phosphorous and feldspar mica as a source of potassium with biological potassium phosphorous fertilizer or biological potassium fertilizer (Silicate bacterium) at different levels (0.0, 25, 50 and 100 g/L) on Ruta graveolens L. plant instead of the chemical fertilizes. Adding biological fertilizer with feldspar or rock phos-phate improved vegetative growth characters such as plant height (cm), branches number/ plant, fresh and dry weights of different plant parts i.e. leaves, stems and roots (g/plant), in addition to some chemical constituents as essential oil, total flavo-noides, P, K, Fe, Zn and Cu content. On the other hand, the main constituents of essential oil and N content were decreased compared with adding recommended chemical fertilizers.
Mostrar más [+] Menos [-]DEVELOPMENT AND REPRODUCTION OF THE TWO PREDATORY MITES EUSEIUS scutalis AND TYPHLODOROMIPS swirskii (ACARI: PHYTOSEIIDAE) AS AFFECTED BY LEAF TEXTURE OF STRAWBERRY PLANTS
2007
Sawsan Elsawi | Mahmoud Alazzazy
The predatory phytoseiid mites Euseius scutal-is (El-Badry) and Typhlodrompis swirskii (Athias–Henriot) successfully developed and reproduced on strawberry leaves, infested with mymphs of the two-spotted spider mite Tetramychus urticae kock as prey, of both Yaeel (smooth slight hairy) and Vantana (rough dense hairy) cultivars indicating a different effect of leaf surface on their behaviour at 27o C and 70% RH.Yaeel leaf was the most appropriate surface and Vantana ones was the least. Longevity was the greatest on Yaeel (31.92 and 28.48 days) and the shortest on Vantana (19.40 and 15.50 days) for each predator, respec-tively. The total number of eggs/ female was 39.00 and 41.34 on Yaeel and 21.02 and 19.68 on Vantana, respectively. Population of the two pred-ators multiply 29.21 and 27.41 in a generation time of 15.78 and 13.93 days on Yaeel, whilst they were (Ro= 14.77 and 14.79) and (T= 14.26 and 12.55 days)on Vantana, respectively. Life table parameters also indicated that the smooth Yaeel leaves are better host-plants for predators in terms rm and erm. Trichomes characteristics on midrib and blade of Yaeel and Vantana strawberry leaves were determined
Mostrar más [+] Menos [-]MANAGEMENT OF BROWN ROT DISEASE OF POTATO
2007
S Mahmoud
Different applications [various potato cultivars, chemical fertilizers, bioagents and chemical in-ducers] were used for controlling brown rot dis-ease of potato. Potato cultivars namely Diamant, Desiree, Herms, Lady Joy, Lady Rossetta, Nicola, Spunta and Valor were variably susceptible to Ralstonia solanacearum, the causal pathogen of brown rot disease. Herms cultivar was the least susceptible. Application of ammonium sulfate, potassium sulfate, Urea, and calcium superphos-phate to infested soil as a single amendment re-duced disease incidence. Application of calcium superphosphate was the most effective treatment. The bioagents Pseudomonas fluorescens, Pseu-domonas putida and Bacillus subtilis were effec-tive in controlling disease when were used sepa-rately and Pseudomonas putida was the most effi-cient. Foliar spraying with different inducers sin-gly [salicylic acid, di-potassium hydrogen phos-phate and tri-potassium phosphate] reduced the disease incidence. Tri-potassium phosphate was the most effective against the disease. Therefore, a management programme was suggested including cultivar Herms, calcium superphosphate, Pseudo-monas putida and tri-potassium phosphate, as in-tegrated treatment. Rotation of these agents showed high effectiveness to disease control as well on the yield increase.
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