Vol. 10, January, 2005

medicaments contenant du tadalafil 1/10 EFFECT OF ENVIRONMENTAL CONDITIONS AND cialis femme enceinte FUNGICIDE TREATMENT ON COTTON SEEDLING DISEASE COMPLEX

M.H.M. Abdel-Rahman, S.M. Moustafa-Mahmoud*, S.A. Al-Wakeel**

andN.M. Gomaa***

*Plant Pathology Institute, Agriculture Research Center, Giza, Egypt.

**Botany Department, Faculty of Science, Cairo University, Giza, Egypt.

***Botany Department, Faculty of Science, Cairo University, El Fayoum, Egypt.

The influence of soil environmental factors on the rate of colonization of cotton plants by several pathogens causing cotton seedling disease complex were studied under different planting dates to evaluate their role on the disease severity. The efficacy of fungicide treatments were also investigated to examine the possibility of their use to control cotton seedling disease complex in greenhouse and field conditions. Of the environmental factors studied, temperature represented by the day-degree was the most important factor affecting cotton stand. A negative correlation was found between day-degree and both fungicide (RTU Baytan-Thiram + Allegiance FL) treated and untreated stand. Disease severity also was influenced by the emergence day-degree, they were directly proportional. Of the pathogens components responsible for seedling disease, que es lerk jet sildenafil Rhizoctonia solani was proven to be the most important pathogen affecting the disease severity. cialis 10 mg comprimé pelliculé R. solani, Pythium spp., Fusarium spp. and generique viagra prix Trichoderma spp.were isolated from cotton plant 24 h after planting, whereas durée d'action viagra Thielaviopsis sildenafil 100mg apotheke basicola was isolated after 4 days of planting or more. Cold soil with high matric potential increased cotton root colonization by muse plus viagra T. basicola, whereas colder soil increased its colonization by commande de viagra en ligne R. solani and drier soil had lowered colonization by site pour commander cialis Pythium spp. R. solani colonization to cotton plants affected the amount of disease when the temperature was low, but at higher temperature there was no value of its isolation data for quantifying the disease. Treating cotton seeds with the fungicides RTU Baytan-Thiram and Allegiance FLincreased cotton stand in the planting seasons 2002 and 2003, but the fungicidal effect was more pronounced in colder season, 2002, than in the warmer season, 2003. Fungicide also reduced the isolation frequencies of different cotton seedling disease pathogens associated with the disease especially during the first 4 days after planting.

2/10 Biocontrol of cotton SEEDLING damping-off disease using binucleate Rhizoctonia

M.H.M. Abdel-Rahman, S.M. Moustafa-Mahmoud*, S.A. Al-Wakeel**

and N.M. Gomaa***

*Plant Pathology Institute, Agriculture Research Center, Giza, Egypt.

**Botany Department, Faculty of Science, Cairo University, Giza, Egypt.

***Botany Department, Faculty of Science, Cairo University, El Fayoum, Egypt.

The ability of three binucleate Rhizoctonia (BNR) isolated from cotton seedling rhizosphere to control cotton damping-off disease, caused by R. solani, was examined in comparison with that of Trichoderma virens isolates and of two fungicides to control the disease. Of the treatments evaluated, BNR, BNR-mixture of isolates and the fungicide (RTU Baytan-Thiram +Allegiance FL) treatments increased cotton stand significantly relative to the untreated control. The BNR treatments were as effective as the fungicide particularly in the greenhouse study. In the field studies, BNR treatments increased stand under heavy disease pressure in the artificially infested soil, but were not as effective as the fungicide treatment. In general, Trichoderma virens and the fungicide Actigard failed to increase stand relative to the control treatment in both greenhouse and the field. Treatments with Fungicides or BNR isolates decreased the colonization of cotton roots by R. solani.

 

3/10 INCIDENCE OF BACILLUS CEREUS IN EGYPTIAN COMMERCIAL RICE AND MILK PLATE AND ITS CONTROL BY NISIN

U. M. Abdul-Raouf, M.M. Afifi. and S.G. Ali.  

Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Assuit 71524, Egypt.

Bacillus cereus is an aerobic spore-former commonly found in raw and processed foods. This study was undertaken to determine the prevalence of Bacillus cereus in raw milk, uncooked rice and commercial rice and milk plate (the most famous desert meal in Egypt). Also determination the anti-microbial activity of different concentrations of commercially nisin toward, the food-borne pathogen, Bacillus cereus on rice and milk plate kept at 5oC for up to 7 days. The inoculated level of Bacillus cereus was 102 and/or 105 cfu/g. The used concentration of nisin were 800, 1600 and 2400 RU/g for this purpose. Bacillus cereus was isolated from 100% of raw rice, 20% of raw milk and from 60% of commercial., cooked rice and milk plate samples collected from different retail market and restaurant in Assuit Governorate, Egypt. pH of cooked rice and milk plate was not affected with inoculation level and/or nisin concentrations. The inhibitory effect of nisin depends on on its concentration and the initial of inoculum size. The addition of 1600 RU/g nisin to inhibit the growth of Bacillus cereus in cooked rice and milk plate at refrigerator temperature (5oC) was recommended.

 

4/10 SEROLOGICAL AND CYTOCHEMICAL STUDIES ON SUGARCANE MOSAIC POTYVIRUS

M.H. Abdel-Ghaffar and M.M. Hazaa*

Department of Agricultural Microbiology (Virology Lab.), Faculty of Agriculture,             Ain Shams University, P.O. Box 68 Hadayek Shubra 11241, Cairo, Egypt.

*Department of Botany, Faculty of Science, Zagazig University (Benha Branch), Benha, Egypt.

Sugarcane mosaic potyvirus (SCMV) is considered to be the most common virus infecting sugarcane in Egypt. In this study, strain E of SCMV (SCMV-E) was propagated on Sorghum bicolor cv. Rio plants, and purified by differential centrifugation followed by density gradient centrifugation. Ultraviolet absorption spectrum of the purified virus showed a typical curve of nucleoprotein with an A260/280 ratio ranged from 1.20 to 1.40. The average yield of the purified virus was estimated to be 1.3-1.5 mg /100 g of virus-infected sorghum leaf tissues. Electron microscopy revealed flexuous filamentous particles with the length of majority ranged between 700-750 nm. The polyclonal antibodies (PAbs) were successfully raised against the purified SCMV-E and its titer determined by R-ELISA. The SCMV-IgGs were separated from the whole antiserum using the caprylic acid procedure. The results of immunogold electron microscopy of virus particles confirmed the specificity of SCMV-IgGs obtained after single immunization and early bleeding of rabbits. Cells of healthy sorghum plants as well as those of SCMV-infected plants were examined by electron microscopy to determine the location of ATPase activity in both healthy and virus infected plants, ATPase activity was found in plasma membranes, chloroplast thylakoid membranes, nuclear membranes and in mitochondria. In virus-infected cells, ATPase activity was also observed in plasmodesmata and in cytoplasmic vesicles which were found in close proximity to the virus-specific cylindrical inclusion bodies of laminated aggregates and at the ends of arms of pinwheels. This confirmed that, the genome of SCMV-E contains conserved sequences characteristic of ATPase activity.

 
5/10 PLANKTONIC DIATOM FLORA OF CERTAIN WATER RESOURCES IN THE GREATER CAIRO.

A.A. El-Awamri, A.M. Shaaban and A.I. Saleh

Botany Dept., Faculty of Science, Ain Shams Univ., Cairo, Egypt

The present investigation concerned with the study of the planktonic diatom flora of certain water resources in The Greater Cairo. Seasonal variations of phytoplanktonic diatom flora as well as physico-chemical characters of River Nile (at Cairo), El-Sharkawia Canal (at El-Qaleobiyah), El-Moheet Drain and El-Ganabya El-Yomna El-Baharya Drain (at Giza)were studied. A total of 139 taxa related to 30 genera were recorded from these localities. Maximum number of individuals at these water resources was recorded in winter. Average concentrations of most cations and anions as well as electrical conductivity values recorded at drains were higher than those recorded at River Nile and El-Sharkawia Canal. A pronounced decrease in the number of individuals/L recorded at drains as compared with those recorded at River Nile and El-Sharkawia Canal was observed.Melosira granulata, M. granulata var. angustissima, Cyclotella ocellata, Synedra ulna var. danica and Stephanodiscus hantzschiiwere the most influential species in the productivity of these water resources. Through this study 8 diatom species were recorded for the first time in River Nile; these were Achnanthes brevipes var. intermedia, Caloneis clevei, Fragilaria construens var. subsalina, Gomphonema acuminatum var. coronatum, Neidium iridis, Nitzschia pellucida, Pinnularia braunii var. amphicephala and P. viridis var. intermedia.

 

6/10 QUINOLONES RESISTANCE IN STAPHYLOCOCCUS AUREUS MEDIATED BY Nor A EFFLUX PROTEIN

R.A.A. El-Domany, E.E. Habib and A.A. Abd Al-Aziz

Microbiology Departments, Faculty of Pharmacy, El-Minia, Egypt.

El-Mansura and Tanta Universities

Ten fluoroquinolones resistant and one sensitive Staphylococcus aureus clinical isolates were tested for their susceptibility to four fluoroquinolones and ethidium bromide to determine their MICs for these compounds. High level of resistance was observed for norfloxacin and ofloxacin as the MICs ranged from 128-256 µg/ml, while lower level of resistance to levofloxacin (MICs ranged from 32 to 64 µg/ml) was obtained. The MICs of ciprofloxacin ranged from 64-128 µg/ml. All the ten quinolones resistant S. aureus isolates were resistant to ethidium bromide (MICs ranged from 64-256 µg/ml). Ethidium bromide was used in this study as a diagnostic agent for the Nor A efflux protein since, active efflux represent the only known mechanism of resistance to this compound. Efflux of ethidium bromide was studied fluorimetrically and the results indicated that there is a marked decrease in the fluorescence of ethidium bromide due to its active extrusion from the cells. Addition of 20 µg/ml of the plant alkaloid reserpine not only resulted in inhibition of ethidium bromide efflux but also restore the bactericidal activity of quinolones against the resistant S. aureus isolates tested as indicated by the reduction in the MICs by 7-10 fold dilutions. Furthermore, reserpine suppress the emergence of ciprofloxacin resistant S. aureus upon in vitro selection with this drug. Moreover efflux of ethidium bromide was inhibited by addition of 100 µg/ml of the proton pump inhibitor omeprazole suggesting that Nor A efflux system is an energy dependant. In conclusion quinolones resistance in S. aureus were mediated by Nor A efflux protein. Therefore combination of Nor A inhibitor with quinolones could improve the efficacy of this class of antimicrobials.

 

7/10 THE RECOVERY OF HEAT, FREEZE AND ACID INJURED ESCHERICHIA COLI O157: H7 ON THE THIN AGAR LAYER (TAL) METHOD AND NEW DYE CONTAINING MEDIUM (SALAH-FUNG-E7-I)

S.G. Ali

Department of Botany and Microbiology, Faculty of Science, Al-Azhar University, Assuit Branch, Assuit, Egypt.

Aniline blue-Metanil yellow agar (ABMY-Salah -Fung-I agar) is a selective differential plating medium which can inhibit heat, freeze, or acid injured E. coli O157: H7 from growing, whereas Tryptic Soy agar (TSA), a nonselective medium, does not. SFE7-I medium was developed for differentiation between E. coli O157: H7 and other bacteria. Thin agar layer provides selectivity of isolation of E. coli O157: H7 from other bacteria in the sample by overlaying 14 ml of nonselective medium (TSA) onto prepoured and solidified SFE7-I medium in a 8.5 cm-diameter petri dish. During the first few hours of incubating the TAL plate, the injured E. coli O157: H7 repair and start to grow on the TSA. During the resuscitation E. coli O157: H7 start to produce a typical reaction (yellow color with yellow zone) and selective agent inhibits other microorganism. The recovery rate of heat and freeze injured E. coli O157: H7 inoculated in ground beef, milk and peptone water and the recovery rate of acid injured E. coli O157: H7 inoculated in ground beef and peptone water. on the TAL method was compared with TSA, and. SFE7-I. No significant difference occurred between TSA and TAL (P> 0.05) for enumeration of heat, and freeze injured E. coli O157: H7 from ground beef, peptone water, and milk, in the addition there is no significant difference occurred between TSA and TAL (P> 0.05) for enumeration of acid injured E. coli O157: H7 from ground beef and peptone water. However the recovery rate of the pathogen on TAL was significantly higher than that on SFE7-I agar (P < 0.05).

 

 

8/10 DETECTION OF FUMONISIN B1 PRODUCED BY F. MONILIFORME AND ITS CONTROL BY GAMMA RADIATION AND FOOD PRESERVATIVES

N.H. Aziz, Z.A. Mattar, A.A.M. Shahin.

Radiation Microbiology Department, National Center for Radiation Research and Technology, Nasr City, Cairo, Egypt.

The distribution of Fusarium species and the effect of gamma irradiation and food preservatives on fumonisin B1 production by F. moniliforme in poultry diet was investigated. Fusarium infection of the commerical whole feedstuff samples ranged from 20 to 90% and F.moniliforme was the predominant Fumonisin B1 producing species. Fusarium counts ranged from 2.2 x 10 to 8.2 x 104 CFU/g in feedstuff. Total viable population of F. moniliforme and fumonisin B1 decreased significantly by increasing gamma irradiation doses in poultry diet. No growth or fumonisin B1 production occurred at 6.0 kGy. Increasing the concentrations of NaCl, potassium sorbate and sodium benzoate reduced the growth of F.moniliforme as well as the accumulation of fumonisin B1. At 2.0 kGy a sharp drop in the detoxification rate (91 – 96%) in fumonisin B1 occurred in poultry diet supplemented by 3% NaCl and 300 ppm of sodium benzoate and potassium sorbate. The combined effect of gamma radiation (2.0 kGy), 1%, NaCl and 100 ppm of sodium benzoate and potassium sorbate detoxified the content of fumonisin B1 by 100% in poultry diet.

 

9/10 GAS CHROMATOGRAPHIC PURSUING OF SUEZ –GULF PETROLEUM CRUDE OIL BIOREMEDIATION.

1- EFFECT OF DIFFERENT TEMPERATURES.

BY

A.Y. El-Nagar, R.A. Bayoumi* and H.R. Madian**

FROM

Egyptian Petroleum Research Institute (EPRI), Scientific Research Ministry, El-Hay El-Tamin, Madenit Nasr, Cairo, Egypt.

*Botany&Microbiology Department, Faculty of Science (Boys), Al-Azhar University, Cairo, Egypt.

**Fermentation Biotechnology & Applied Microbiology (Ferm-Bam) Center, Al-Azhar University, Cairo, Egypt.

In the present investigation forty one crude oil utilizing microbial isolates (twenty one bacteria, fourteen filamentous fungi, four actinomycetes, and two yeasts) were isolated from crude oil polluted soil and water samples collected from nine different localities in addition to well identified Saccharomyces cerevisiae strain. All forty two crude oil utilizing microbial isolates exhibited a good growth on the mineral salts medium supplemented with Suez-Gulf petroleum crude oil as a sole source of carbon and energy. All forty two microbial isolates were surveyed by using qualitative and quantitative determination of crude oil biodegradation by capillary gas chromatography (CGC) technique. Two unidentified most potent crude oil utilizing microbial isolates were identified as Penicillium chrysogenum-RS-F7, and Streptomyces rimosus–EPRI-Y3.The three most potent microbial isolates viz. Penicillium chrysogenum-RS-F7; Streptomyces rimosus–EPRI-Y3, and Saccharomyces cerevisiae-Ferm-Bam-Y3 were tested for their biodegradation abilities on Suez Gulf petroleum crude oil at different incubation periods. Hydrocarbon concentrations were determined quantitatively by capillary gas chromatography (CGC) according to the internal standard method. The CGC analysis indicated that all studied isolates can degrade the crude oil at different incubation periods in different degrees, also, the time 15 days was found to be the prefer time for maximum degradation of the crude oil pollutants. Penicillium chrysogenum-RS- F7 was found to be the most efficient single isolate giving complete degradation of the crude oil. Combination between Penicillium chrysogenum-RS-F7, Saccharomyces cerevisiae-Ferm-Bam-Y3 and also combination between Penicillium chrysogenum-RS-F7 and Streptomyces rimosus-EPRI-A4 exhibited a pronounced effect on the complete degradation of the Suez Gulf petroleum crude oil contaminants. This study emphasized the ability to using microbial isolates in the bioremediation technology especially environmental pollution caused by crude oil spills contaminating various environments.

 

10/10 MORPHOLOGICAL, PHYSIOLOGICAL, CHEMICAL AND MOLECULARSTUDY ON GENUS SACCHAROMONOSPORA

N.A. Abd-Allah

Microbiology Department, Faculty of Science, Ain-ShamsUniversity, Cairo, Egypt.

The characters of three local isolates belonging to the genus Saccharomonospora (one from soil and two from compost) were compared with the characters of the type strain Saccharomonospora viridis NRRL-B3044. Comparison was carried out depending on differences in some morphological and physiological aspects, in addition to amplified polymorphic DNA analysis and chemical composition of the cell wall. Results revealed that morphological characters and chemical composition of the cell wall, especially with reference to diagnostic sugars in cell hydrolysate were valuable in the identification of an actinomycete to the genus level. On the other hand, the application of PCR-based analysis techniques provided a rapid, accurate and reliable way to identify members of Saccharomonospora to the species level. Data also revealed that the genus Saccharomonospora should be re-evaluated from the taxonomic point of view using more useful taxonomic markers

 

11/10 FACTORS REGULATING PRODUCTION OF NISIN BY LACTOCOCCUS LACTIS

H. Abdel Karem, H. Hussein, S. Badr*2 and D.El-Hadedy

FROM

National Center for Radiation Research and Technology, Nasr city, Cairo, Egypt.

*Department of Botany, Faculty of Science, Tanta University.

The effect of growth medium, pH, temperature, agitation, inoculum size, yeast extract, surfactants and gamma irradiation on the production of nisin by Lactococcus lactis Fc2 (local isolate) under shaking flasks conditions have been considered. Lactococcus lactis strain selection and optimization growth conditions to maximize nisin production were conducted. Whey was the suitable medium than MRS in nisin production. At pH 6 and 30οC nisin activity increased to 10000 Au/ml.. As to agitation at 120 rpm a slightly increased in nisin production whereas, 12% inoculum size gave the highest level of nisin. Using different concentrations of yeast extract increased the nisin activity till 0.6 % level of yeast and decreased thereafter. Addition of surfactants, Tween 80 and Triton X-100 increased nisin production, however Tween 20 had a negative effect. Triton X-100 gave the highest level of nisin activity and 0.02% was the optimum. An experiment was conducted to study the efficiency of gamma irradiation on Lactococcus lactis Fc2 for increasing the production of nisin. Irradiation dose level at 1.5 kGy secreted the highest amount of nisin (14000 Au/ml) comparing with 5000 Au/ml of control one (basal medium). Nisin yield was 0.72 g/l in whey by chloroform extraction.

12/10 RAPID DISCRIMINATION OF PROVIDENCIA SPECIES ANDSTRAINS BY ENTEROBACTERIAL REPETITIVE INTERGENIC CONSENSUS PCR ANALYSIS

M.S. Mansy

Microbiology Department, Faculty of Pharmacy, Al-Zaytoonah University,

Amman, Jordan.

Repetitive – element PCR (rep – PCR) with primers based on Enterobacterial repetitive intergenic consensus (ERIC) repeated DNA sequence was used for the type strains of the five different species of the genus Providencia. This technique was applied by using either extracted genomic DNA or preparation of whole bacterial cells directly. PCR fingerprints with primers based on the ERIC repeat (ERIC–PCR) revealed species-specific and strain – specific band patterns for the various Providencia   DNA fingerprints obtained from ERIC – PCR of extracted genomic DNA or from preparation of whole cells yielded comparable patterns. This approach was compared with the phenotypic and genotypic typing methods such as antimicrobial susceptibility pattern, biotyping, PCR– based RFLP profile, protein pattern and ribotyping. Distinct ERIC–PCR patterns were detected within Providencia species and strains. Twelve and eleven different fingerprint profiles were identified among 14 and 11 strains of Providencia rettgeri and Providencia stuartii respectively, while Providencia alcalifaciens, Providencia rustigianii and Providencia hemibachae yielded one profile for each. ERIC – PCR is a useful technique for identification and subtyping of Providencia organisms to the species and strains level and offers the advantage of ease of performance, with only small quantities of cells needed for the whole – cell procedure. Strains of Providencia species could be discriminated in about 6 h by this method, which is therefore a rapid and simple technique.

 

 

13/10 PRODUCTION AND PROPERTIES OF AN EXTRACELLULAR BIOPOLYMER FLOCCULANT PRODUCED BY THE NOVEL STRAIN BACILLUS ALVEI

SH.M. Abdel-Aziz

Microbial Chemistry Dept., National Research Centre, Dokki, Cairo, Egypt

Bacillus alvei, a novel local isolate, capable of producing an alkaline biopolymer flocculant by using shrimp shells and yeast extract. B. alvei produced the flocculant during the logarithmic phase of growth at 30°C for 72h, and wide pH range of 4.0-10.0. No significant differences were found in viscosity and activity of the flocculant using a rich medium containing L-glutamic acid (flocculating activity, 98%) instead of shrimp shells (flocculating activity, 96%) as a sole carbon source. The crude flocculant could be efficiently recovered from the supernatant of the culture broth by ethanol precipitation. It was found to be effective for flocculation of charcoal suspension, when added at a concentration of 50 ml/L, over a wide range of pH values (4-11) and temperatures (5-90°C). The flocculant need no cations (Ca2+, Mg2+, Fe2+, or Zn2+) to stimulate its activity. It could efficiently flocculate a variety of particles such as insoluble materials solids, fungal and bacterial cells, and other particles. The molecular weight of the flocculant was estimated to be about 270 kDa. The IR spectra of the flocculant, and loss of the flocculant activity by adding chitosanase, suggested the flocculant to be similar to chitosan.

14/10 SCREENING OF SOME ACTIVITIES OF INDOOR MOULD FUNGI

A.A. Karam El-Din, D.A. Mahmoud, N.M. Hassanein and Y.A. Youssef

Department of Microbiology, Faculty of Science, Ain-Shams University.

In this surveillance a total of 7641 cfu were collected, using the exposed plate method, from the indoor of four sites (home, hospital, school, and university) for a period of one year. Seasonal variation showed a pattern of double peaks in February and October. Home count was the highest among the other sites. Seventy six mould species belonging to 29 genera were recovered during this study. The genus Aspergillus recorded the highest count and A. flavus was the most dominant. Enzymatic activities fo the tested isolates revealed that 65.5% showed cellulolytic activity and 42.3% showed keratinolytic activity. Also 16.6% of the tested strains were able to grow at 37˚C and most of them showed lipolytic, proteolytic and haemolytic activity, which indicate their pathogenic potentiality as opportunistic pathogens

 

15/10 PRODUCTION AND SOME PROPERTIES OF AN INULINASE
PRODUCED BY BACILLUS ALVEI

SH.M. Abdel-Aziz and F.E. Moafi *

Microbial Chemistry Dept. and Microbial Biotechnology Dept.*,

National Research Centre, Dokki, Cairo, Egypt

Biosynthesis of extracellular inulinase by Bacillus alvei, Bacillus subtilis, and Bacillus megaterium bacteria was studied. The optimal parameters for the bacterial growth were pH 8.0, 32oC, and growth duration 72h. Presence of inorganic nitrogen source was necessary for the enzyme production. Maximum inulinase activity from B. subtilis was in presence of sucrose, while both B. alvei and B. megaterium had a high affinity for inulin. Maximum inulinase activity by B. alvei was obtained when 50 g/L of chicory juice was utilized as the substrate as well as pure inulin. The temperature and pH optimum for inulinase activity from B. alvei was pH 9.0 and 80oC, respectively. The enzyme possesses a broad range of specificity towards various substrates; inulinase produced by B. alvei is capable of hydrolyzing the β-1,4, linkage of chitinious polysaccharides. Experimental studies provided that B. alvei produced inulinase free of invertase [I/S ratio, 47.5]. B. alvei is a promising strain for production of inulinase which yields inulinooligosaccharides that have beneficial heath properties.

 

 

16/10 PREPARATION OF LOW MOLECULAR WEIGHT CHITOSAN BY EXTRACELLULAR ENZYMES PRODUCED
BY BACILLUS ALVEI

SH.M. Abdel-Aziz and F.E. Moafi*

Microbial Chemistry Dept. and Microbial Biotechnology Dept.,* National Research Centre, Dokki, Cairo, Egypt

Extracellular enzymes preparation (EEP) produced by Bacillus alvei, tentatively exhibited chitinase, chitosanase as well as cellulase and protease activities. Treatment of chitosan (30% acetylated) with these enzymes decreased their molecular weight from 88,000 to 5000 Da, after 2h. Reduction in viscosity approached zero after 2h of hydrolysis of chitosan by B. alvei enzymes. Enzymatic hydrolysis of chitosan by the EEP increased the solubility of chitosan hydrolyzate (89%). Optimum conditions for the enzymatic hydrolysis were pH 5.5 of chitosan solution (1%) incubated at 37oC for 2h. EEP produced by B. alvei possess the ability to hydrolyze chitin and a wide range of partially deacetylated chitosans. Low-molecular-weight chitosan obtained by the enzymatic hydrolysis of chitosan by EEP could be used in food industry, pharmaceutical and medical fields.

 

17/10 MOLECULAR CHARACTERIZATION FOR MALATHION BIODEGRADING ENZYMES EXTRACTED FROM EGYPTIAN BACTERIAL ISOLATES

Y.A. Mawgoud

Botany Department, Faculty of Science, Cairo University, Giza 12613, Egypt.

Three bacterial isolates were isolated from the screening of 60 soil samples collected from a cultivated area at Kaha, Egypt. The bacterial isolates were identified as Pseudomonas sp. K1, Pseudomonas sp. K2, and Erwinia sp. K. They were grown separately on malathion as a sole carbon and energy source and their filtrates were subjected to gas chromatographic analysis which revealed in the three filtrates a definite sharp peak for malaoxon with retention time 5.93 min-1 in addition to malathion peak (r. t. 4.56 min-1). When a mixture of the three bacterial species was grown on malathion as a sole carbon and energy source, its filtrate analysis revealed an unknown product peak (35%) with retention time 6.18 min-1 in addition to the peaks of malaoxon (42%) and malathion residue (20.4%). Expression of carboxyesterases was investigated in the protein extracts of the bacterial isolates using the polyacrylamide gel electrophoretic method (PAGE). Three isomers of carboxyesterase enzyme were detected in Pseudomonas sp. K2 with different molecular weight (46.2, 45.7, and 42.9 K Da).

18/10 SCREENING AND GROWTH CHARACTERIZATIONS OF THE GREEN LIFE STOCK OF DRILL WATER FROM JEDDAH, SAUDI ARABIA

III- ENHANCEMENT OF SECONDARY CAROTENOIDS BY OXIDATIVE STRESS IN RELATION TO MEDIUM COMPOSITION

A.B. El-Sayed and A.A. Abdel-Maguid

Fertilization Technology Department, National Research Centre

The objective of the present work was to select the most suitable medium engaged the accumulation of secondary carotenoids in the green alga Scenedesmussp. in presence of some oxidative stress. Induction conditions -based on salting out and nitrogen deficiency- were performed on four growth media of the isolated alga Scenedesmus sp. Re-composed-BG-II, Mg-residences enriched medium, Zarrouk medium and the formulated medium were used to achieve algal growth. Formulation of the latest medium was done based on chemical analysis of the natural water resource of the isolated alga from Saudi Arabia drill water. Growth was daily estimated as dry weight, total chlorophyll, and total carotenoids. The formulated medium exhibited more resistance against dry weight decline as compared with other media used. As for total chlorophyll, the formulated and re-composed BG-II growth media were found to be more sensitive against chlorophyll decomposition, while both of Zarrouk and Mg-residence media represented slight increase for chlorophyll content. An opposite manner of chlorophyll results was observed with carotenoids accumulation. Thus, carotenoids formation with such media could be ascribed to the differences on the chemical composition of growth medium used with the aid of Fe+2 as oxidative stress factor.

 

19/10 SOME PROPERTIES OF CYTIDINE DEAMINASE OF

ASPERGILLUS PHOENICIS

O.M. Abdel-Fatah

Department of Microbial Chemistry, National Research Centre, El-Tahrir Street, Dokki, Cairo, EGYPT

The cell-free extracts of 3-4 days old mats of Aspergillus phoenicis previously grown on nitrate as the sole source of nitrogen exhibited the capability to catalyze the hydrolytic deamination process of cytidine. The same extracts could not catalyze the deamination of cytosine. Uridine was identified chromatographically as a product of enzyme catalysis. Maximum enzyme activity observed in citrate-phosphate buffer at pH 6.0 and 45°C. Incubation the extracts at 45°C for 60 minutes in the absence of cytidine had no effect on deaminase activity, whileas exposing the extracts at 50°C, 55°C, 60°C and 70°C caused gradual decrease in enzyme activity throughout the time of exposure. Frequent freezing and thawing of the extracts for 72 hours (3 cycles) resulted about 80% loss of deaminase activity. Dialyzing the extracts and addition of ethylene diamine tetraacetate (EDTA) to the crude extract had no effect on enzyme activity, indicating the non-requirement of metal ion(s) for enzyme catalysis. None of the metal ions under study caused activation of enzyme activity, whileas each of CuSO4, HgCl2 and CoSO4 caused a complete inhibitory effect on the enzyme activity. The results obtained indicate that there is no evidence for the involvement of sulfhydryl group in enzyme catalysis.

 

 

20/10 DIRECT FERMENTATION OF SOME STARCHY GRAIN MILL WASTESTO L (+)-LACTIC ACID AND PROTEIN ENRICHED FERMENTED ANIMAL FEED BY Rhizopus oryzae NRRL 395

A.M.A. Dokhan; S.A. El-Sayed; G.A.E. Amin* and G.M.E. Khalaf-Allah*

Agric. Microbiol. Res. Dept., Soils, Water and Environ. Res. Inst., Agric. Res. Center, Giza, Egypt

* Agric. Microbiol. Dept., Fac. of Agric., Cairo University

L(+)- lactic acid, amylolytic enzymes and fungal protein production by Rhizopus oryzae NRRL 395 grown on some starchy grain mill wastes of sorghum, yellow corn and barley, were determined. The rates of carbohydrate consumption and production of both L(+)- lactic acid and fungal protein were found to be influenced by the type and concentration of substrate. L (+)- lactic acid and amylolytic enzymes either produced from yellow corn (353 g/kg and 12 u/mg protein, respectively) or sorghum (263 g/kg and 10.2 u/mg protein, respectively) were much higher than that produced from barley (210 g/kg and 9.2 u/mg protein, respectively). The optimal solid: liquid ratio for production of both L(+) – lactic acid and fungal protein were found to be 1.5:10. The fungus succeeded to degrade 54.8, 50.4 and 51.0% of starchy grain mill wastes of yellow corn, sorghum and barley, respectively, and upgraded the protein content of the residual fermented substrate due to the fungal protein produced. Amino acid profile of R. oryzae protein revealed presence of 17 amino acids, 8 of them were essential amino acids. It showed the existence of the same amino acids of egg albumin, with variable proportions. Although, R. oryzae protein has relatively deficient of sulphur amino acids (cystine and lysine) it has a relative advantage among other special references of microbial protein.

21/10 SOLUTION OF THE PROBLEMS OF MALCLARIFICATION, AND SEPARATION IN MANGO SYRUP BY FUNGAL PECTINASES

M.M. Afifi, S.G. Ali and E.M. Mabrouk

Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Assuit Branch, Assuit

The present investigation is concerned mainly on the treatment of separation, and malclarification problems occurring in mango syrup produced industrially for commercial use in the field of ready made foods for human consumption. Three pectinases were used: crude pectinase produced by Aspergillus niger, S-48 TAT, purified pectinase and pure pectinase {Koch-Light Laboratories (KLL) Ltd., Colnbrook-berks, England, obtained from Aspergillus usamii mutant shirosami}. The percentage (%) in reduction of viscosity (R.V.) of the fruit juice samples was the main evidence for solving the problem of turbidity and/or separation accompanied by clear cut clarification of treated juice sample. This study emphasized that the optimum enzyme concentrations (units/ml) were 8721.44, 4498.72 and 6748.08 for crude ST, purified ST and KLL-pectinases respectively. An optimum incubation period of 30,90 and 120 min. for crude, purified ST-and KLL-pectinases respectively. The best incubation temperatures were 20°C for crude ST-pactinase and 10°C for both purified ST-and KLL-pectinases. An optimum pH value (using citrate-buffer) was 3.2 (for all enzymes used). The optimum application conditions for the three enzymes used were detected after the shelf life of mango syrup samples (i.e. six months) at both optimum pH and optimum temperatures corresponding to final pH (2.97, 2.91 and 2.89) for purified crude ST-, purified ST- and KLL-pectinase respectively.                                                                                                                    

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