خيارات البحث
النتائج 21 - 30 من 57
SCREENING OF ANTIMICROBIAL AND CYTOTOXIC ACTIVITIES OF SOME ACTINOMYCETES ISOLATED FROM CONSTRUCTED WETLAND SYSTEM
2006
A total of 174 actinomycete cultures were isolated from a constructed biological water treatment system (BIOWATSYST)established at Abu Attwa station in Ismailia city, Egypt and funded by the European Commission Grant No.IC18-CT97-0163. The isolates were identified to belong to eight genera; Nocardia, Streptomyces, Intrasporangium, Micromonospora, Nocardioides, Actinomadura, Nocardiopsis, and Thermomonospora. They were screened for their antibacterial, antifungal and cytotoxic activities against certain human and plant pathogens. Antimicrobial activities were determined by measuring bacterial and fungal growth inhibitions while cytotoxic activity was studied by using the Artemia salina bioassay. Thirty two percent of isolated cultures displayed antibacterial activity, 15% displayed antifungal activity and 9% displayed cytotoxic activity. Members of genus Streptomyces has recorded as the most frequent active isolates against tested bacteria (42%) and fungi (49%). However, the most cytotoxic activity was found with members of genus Nocardia (46%). Results evaluated the fact that actinomycetes isolated from such systems could be considered as promising source for antimicrobial and cytotoxic bioactive agents.
اظهر المزيد [+] اقل [-]PHYSICAL AND STRUCTURAL PROPERTIES OF THE PROMISING EGYPTIAN LONG STAPLE COTTON CROSS (GIZA 89 X GIZA 86)
2006
Nadia S. Abd El-Gawad
A promising cotton inbred line characterized by high yielding ability, earliness in maturity and better fiber quality was developed via pedigree selection from the subsequent segregating generations of a cross between the two long-staple cvs.; Giza 89 and Giza 86 by the Cotton Breeding Section of the Cotton Research Institute. The purpose of this investigation aimed at assessment of the superiority of the physical and fine structural properties of the promising line derived from the cross (Giza 89 x Giza 86) over its parents. The results indicated that: - The promising line surpassed its parents in upper half mean length, uniformity index, fiber strength, fiber elongation, micronaire value, maturity ratio, hair weight, dry fiber ribbon width, swollen fiber diameter, convolution number / cm., reversals number/ cm. and yarn strength. - There were highly significant positive correlations between upper half mean length, uniformity index, convolution number/cm., fiber bundle strength and yarn strength. - Highly significant negative correlations exhisted between dry fiber ribbon width, swollen fiber diameter, reversals number and bundle strength. The promising line is now under propagation for growing as a commercial cultivar and would replace both parents in their growing areas.
اظهر المزيد [+] اقل [-]NOSOCOMIAL INFECTION IN SURGICAL HOSPITAL IN ZAGAZIG UNIVERSITY
2006
E.Y Tohamy | A.A Shaheen | Samah F. El-Awadi
Surgical site infection (SSI) remains an important cause of morbidity and mortality among hospitalized patients. A total of 254 bacterial isolates were collected from 303 surgical specimens which were isolated from 92 males (53.2%) and 81 females (46.8%), their mean ages were 39.6±16.05 years (ranged from 1 month to 74 years). These isolates were identified as Staphylococcus aureus,Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris, Pseudomonasaeruginosa and commensal Gram+ve and Gram-ve bacteria. The most effective antibiotics were imipenem while ampicillin and penicillin G (First and second generation of b-Lactam) showed much lower activity against all types of bacterial strains. The minimum inhibitory concentrations (MIC) of imipenem determined by E-test were 0.047- 0.064 , 0.125, 0.19, 0.25 and 0.75mg/ml against Staphylococcus aureus, Escherichia coli, Proteus vulgaris, Klebsiellapneumoniae and Pseudomonas aeruginosa respectively.
اظهر المزيد [+] اقل [-]NUMERICAL STUDY ON SOME ACTINOMYCETES ISOLATED FROM BURULLOS LAKE IN EGYPT
2006
Twenty nine actinomycetes isolates were isolated from Burullos Lake and characterized taxonomically for 62 phenotypic traits including morphological; biochemical, nutritional, substrate utilization and anti-microbial activities. The results were analyzed by numerical techniques using the simple matching coefficient (SSM) and UPGMA clustering. At 54% similarity level, the majority of the isolates were grouped into six phena (A, B, C, D, E and F). Only two isolates were grouped separately and formed two single clusters at the same level of similarity. A representative isolate from each phenon was identified. The isolates were found to be Streptoverticillum morookaense, Nocardia brasiliensis, Streptomyces alanosinicus, Streptomyces globosus and Streptomyces gancidicus
اظهر المزيد [+] اقل [-]HEAVY METAL BIOSORPTION BY SOME BACTERIAL SPECIES ISOLATED FROM DRINKING WATER AT DIFFERENT SITES IN SHARQIA GOVERNORATE
2006
Eman Y. Tohamy | Azza A. Abou-Zeid | M.M . Hazaa | Reham A. Hassan
The nine most frequent bacterial strains out of 127 were isolated form ten drinking water samples collected from tap water and bottled water in sharqia governorate. The nine isolates were purified and examined for their resistance to increasing concentrations of two heavy metal ions, lead (Pb+2) and iron (Fe+3). Four stains out of the nine isolates encoded I, II, IV, and VIII showed the highest efficiency of both Pb+2 and Fe +3 uptake from nutrient broth media containing 100 ppm of the heavy metal ions. The four bacteria were preliminary identified and then confirmed by the Biolog examination as Corynebacterium jeikeium, Pseudomonas putida biotype A, Acinetobacter calcoaceticus and Acidovorax delafieldii. The increased concentrations of Pb+2 ions (from 100 to 500 ppm) in nutrient broth media had deleterious effect on the process of heavy metal uptake (biosorption) by all the four selected isolates. Whereas percentage of Pb+2 uptake decreased from 42.9 to 24%; from 72.6 to 42%, from 78.9 to 37% and from 68.8 to 45%, for the four selected isolates, respectively. Meanwhile there was slight decrease change in Fe+3 uptakes percentage accompanying the increase in heavy metal ion concentration. Optimization of the cultural conditions releaved maximum uptake op pb+2 and Fe+3 by the four tested strains in presence of 100 ppm heavy metal concentration when incubated at 25oC except for Acinetobacter calcoaceticus at 35oC in case of Pb+2 uptake, when pH, was adjusted at 5 under static conditions. Upon addition of 50 ppm Cu+2 ions to broth media supplemented with 100 ppm Pb+2 ions, the percentage of metal biosorption by the four tested isolated decreased between 41.11% and 48.45% according to type of strain. Similarly presence of Cu+2 ions caused decrease in Fe+2 uptake by the four isolates ranging between 29.14-45.1%. Percentage of Pb+2 ions uptake by the tested bacteria sharply decreased when a sterile tap water sample was used as natural medium for cell-metal contact. The percentage of uptake inhibition of Pb+2 ranged between 57-65.23% and between 75.1-84.27% for Fe+3 ions. Cell hydrolysate of three tested bacteria appeared to be free from plasmid DNA proving that the genetic character of heavy metal resistance is plasmidless and related to chromosmal DNA in case of Cory. jeikeium, P. putida and A. delafieldii. On the other hand, Acinet. Calcoaceticus contained plasmid of size 23.130 kb. Examining Acientobacter calcoaceticus using transmission electron microscope revealed the accumulation of Pb+2 ions on bacterial cell surface and the intracellular absorption of Fe+3 ions.
اظهر المزيد [+] اقل [-]PLANT GROWTH AND NUTRIENTS UPTAKE AS INFLU-ENCED BY APPLICATION OF FARMYARD MANURE AND SOME NATURAL MINERALS TO SANDY SOILS
2006
Wafaa M.T. El-Etr | Gehan H. Youssef | Laila K.M. Ali
A field experiment was carried out for two seasons 2001 and 2002 at Ismailia Agric. Res. Station to study the comparative effect of farmyard manure (FYM) application, individually or in combination with natural minerals, as sources of micronutrients. Such effect was studied during successive growth stages of wheat (vegetative stage, flowering stage and harvest stage), as well as after maize harvesting, on plant growth, nutrients uptake and wheat - maize productivity. The experiment was designed in a randomized complete block design with three replications. Two levels of FYM (2 % and 3 %) and three natural minerals, i.e., magnetite (iron oxide, Mag.), basic slag (Bas.) and manganese dust (Md.) at three rates 0.02 %, 0.05 % and 0.07%, respectively. Obtained results revealed that, at vegetative stage, mineral fertilizers (MF) treatment positively affected the dry matter of both shoots and roots of wheat plants along with contents of nitrogen and potassium in both shoots and roots as well as shoot/root ratios. At flowering stage, obtained data showed that applied farmyard manure at the rate of 3 % (F2) significantly affected the dry matter of both shoots and roots as well as their contents of N, P and K. A similar trend was obtained for micronutrients uptake at the two indicated growth stages of wheat, which recorded high values when FYM, at a rate of 3 % (F2), was applied. On the other hand, obtained results indicated that applied FYM at the rate of 2 % (F1) with high rate (0.07 %) of each of the used natural minerals and FYM at the rate of 3 % (F2) in combination with the moderate rate (0.05 %) of such minerals recorded high values of all tested parameters. In addition, Basic slag (Bas.), generally, gave the highest values, over control, of dry matter content and macronutrients uptake during the studied two growth stages of wheat, (vegetative and flowering stages). The agronomic yield components of wheat (straw, grains and weight of 1000 grains) were increased when MF was applied; such significant increases were obtained in maize yield (residual effect) as a result of applied FYM individually or combined with natural minerals.
اظهر المزيد [+] اقل [-]EFFECT OF SOME CHEMICAL MATERIAL AND GERMINATION MEDIA ON SEED GERMINATION AND GROWTH OF GRAFTED CASIMIROA TRANSPLANTS
2006
Sanna S. Ebeed | Kh.A El-Rouby | A.A Zarad
This investigation was carried out in the plastic house of Horticulture Research Institute, Agriculture Research Center, Giza during two consequent seasons (2002 – 2003) and (2003 – 2004). The study was aimed to enhance growth of Casimiroa rootstock seedlings to reach grafting size in a short time, beside defineding the suitable method of grafting. In this concern, results revealed that seed soaked in MgSO4 at 5 % for 15 min. and planted in media consists of peat and sand at 1 : 1, was increased seed germination percentage (92.1 and 94.8 %) and minimized the germination period (19.1 and 19.3 days), as compared with the other treatments. Thus it reached to the grafting size at a period of (179 and 180 days) in both seasons, respectively. However, Dormex (hydrogen cyanamide) treatment at 2% gave the highest root length (24.6 and 24.8 cm), and number of roots per plant (19.4 and 19.0). Results also showed that shield budding by using soft wood grafts, gave the highest percentage of success (69.2 and 72.4%), shortest period of bud / scion (23.0 and 24.0 days), highest values of scion length (26.5 and 25.7 cm) and highest leaf area (38.28 and 40.67 cm2). However, cleft grafting with softwood grafts increased average number of leaves per sprouted graft (6.0 and 6.6) and shoot scion diameter (0.6 and 0.5 cm). Generally, seeds treated with MgSO4 at 5% berfore sowing in media consists of peat and sand at 1 : 1 in volume, induced healthy and sizeable rootstocks in a short time. Moreover, grafting rootstocks by soft wood grafts was the best method.
اظهر المزيد [+] اقل [-]EFFECT OF PHOSPHATE ROCK AND TRIPLESUPERPHOS-PHATE ON GROWTH AND LEAF N, P AND K CONTENTS OF GROUNDNUT (ARACHIS HYPOGAEA L.) GROWN ON A CLAY SOIL
2006
Elsheikh M.A. | A.M.A. El-Tilib | E.A.E. Elsheikh | A.H. Awad Elkarim
A pot experiment was carried out to investigate the agricultural value of a local phosphate rock (PR) as a source of plant phosphorus compared with that of the cur-rently imported triplesuperphosphate (TSP) .The PR was applied at the rate of 0, 55, and 110 kg P2O5 /ha and the TSP was at the rate of 0 , 45 and 90 kg P2O5 /ha. The growth and leaf contents of N, P and K of groundnut (Arachis hypogaea L.) grown on a clay soil were measured. The experiment continued for two seasons. Phosphatic fertilizers are of low recovery; therefore, they can remain for the next crop. Thus, the pots of the first season were set to study the residual effect of phosphorus in the second season. The results indicated that PR and TSP significantly (P>0.05) in-creased dry weights of shoot and root, leaf contents of N , P and available soil phos-phorus. However, plant height was significantly increased by TSP only. The leaf content of K was neither affected by PR nor TSP application. The results showed a positive effect of the residual PR and TSP on the measured parameters. Moreover, the results revealed that the plant measurements obtained from PR treatments were comparable to those obtained from TSP treatments which indicate that PR can be used as a potential source of phosphorus fertilizer.
اظهر المزيد [+] اقل [-]NATURAL OCCURRENCE OF CITRININ AND BIOCONTROL OF ITS PRODUCING FUNGUS BY Trichoderma hamatum IN RICE GRAINS
2006
Ezzat S.M. | E.F. Abd-Allah
Paddy rice was sampled from El-Sharkia, El-Gharbia, El-Dakahlia and Kafr El-Sheikh governorates, Egypt. Of the 29 samples taken, ten were contaminated with the mycotoxin citrinin. An average of 6.79 x 104 fungal spores per gram rice was found. The isolated fungi represented 47 species belong to 28 genera. The predomi-nant genera were Aspergillus, Cladosporium and Penicillium. Aspergilli were represented by 22 species; Aspergillus niger and A. flavus had the highest occur-rence. Penicillium viridicatum produced the highest amount of citrinin on glucose ammonium nitrate salts broth and rice grains and hence, this isolate was selected as a good producer of citrinin in this study. The presence of Trichoderma hamatum re-duced the amount of citrinin produced by P. viridicatum compared with its respec-tive control. The excessive growth of T. hamatum on P. viridicatum was increased with time. Viability of P. viridicatum conidia decreased by T. hamatum with an in-crease in the incubation period. Chitinases and 1,3-B-glucanase enzyme activity of T. hamatum increased with extending the incubation period on P. viridicatum cell walls up to maximum values at 72 and 84 h, respectively. T. hamatum led to a de-crease in the production of citrinin by P. viridicatum on rice grains compared with the respective control values.
اظهر المزيد [+] اقل [-]IN VITRO PROPAGATION OF SOMATIC EMBRYOGENESIS-DERIVED PLANTLETS OF CITRUS
2006
El-Sawy, A. A. | A. Reda | A. Gomaa | Nansy Danial
Nodal stem segments of in vitro growing somatic embyogenesis and seedling-derived plantlets of sweet orange, C. sinensis (L.) of (Washington navel, shamouti and blood orange cvs.); grapefruit, C. paradisi (L.); Local mandarin, C. deliciosa (Tenor); lemon, C. limon; (L.); citron, C. medica (L.); lime, C. aurantifolia (Christm); rough lemon, C. jambhiri (Lush) and sour orange, C. aurantium (L.) were cultured on MS medium supplemented with different concentrations of BA (0.5,1.0 and 2.0 mg/L) alone or in combination with NAA (0.5 mg/L) for shoot multiplica-tion. The results indicated that somatic embryogenesis-derived plantlets can be suc-cessfully propagated in vitro with a good vigor compared with germinated seedlings. A large number of proliferated shoots were produced when these explants were cul-tured on MS medium containing 0.5mg/L of BA combined with 0.5mg/L of NAA. Most obtained shoots were rooted on half-strength MS medium containing 0.5 mg/L of NAA. These in vitro grown plantlets were then successfully transferred to green house through acclimatization process.
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