12 results on '"Neveen M. Khalil"'
Search Results
2. Extremozymes from extremophilic microorganisms as sources of bioremediation
- Author
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Tarek A. A. Moussa and Neveen M. Khalil
- Subjects
Cadmium ,Bioremediation ,chemistry ,Thermophile ,Environmental chemistry ,Microorganism ,chemistry.chemical_element ,Extremophile ,Psychrophile ,Halophile ,Arsenic - Abstract
Extremophiles are a group of organisms growing in a wide range of extreme environmental conditions. The extremophilic microorganisms are diverse and are classified into psychrophiles (− 2°C to 20°C), thermophiles (55–121°C), piezophiles (> 500 atm), halophiles (2–5 M NaCl or KCl), metallophiles (high concentrations of metals, e.g., copper, zinc, lead, cadmium, and arsenic), alkaliphiles (pH > 8), and acidophiles (pH
- Published
- 2022
3. Biochemical Activity of Propolis Alcoholic Extracts against Fusarium oxysporum hm89
- Author
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Neveen M. Khalil, Hala M. Ali, and Ahmed E. Ibrahim
- Subjects
integumentary system ,Ecology ,biology ,food and beverages ,Cell Biology ,Plant Science ,Quinic acid ,Cellulase ,Erythritol ,Propolis ,Antimicrobial ,biology.organism_classification ,Enzyme assay ,chemistry.chemical_compound ,chemistry ,Fusarium oxysporum ,Genetics ,biology.protein ,Food science ,Pectinase ,Ecology, Evolution, Behavior and Systematics ,Biotechnology - Abstract
Propolis was responsible for in vitro growth suppression of some tested phytopathogenic fungi. Four tested species were partially inhibited by using propanolic or ethanolic extract associated with promising growth reduction of Fusarium oxysporum in a per cent of growth recorded 38.2% or 58.9% during propanolic or ethanolic application, respectively, while Helminthosporium sp. and Cladosporium sp. showed unexpected activation of growth during propanolic or ethanolic extract applications. The antimicrobial products identified during GC-MS analysis of the propolis propanolic extract were Pyrazole, Quinic acid, D-lactic acid, Pentanoic acid, Erythritol and sulfonamide derivatives. The SDS gel electrophoresis of soluble proteins of Fusarium oxysporum treated with propanolic or ethanolic propolis extracts showed a specific protein band at 26.002 kDa with the untreated pathogen, and several characterized bands at 21.160, 26.012, 28.666, 38.44, 102 kDa related to propolis propanolic extract (2) and finally a two markedly visible bands at 18.871, 33.083 kDa with propolis ethanolic extract (3). The decrease in enzyme activity of cellulase and pectinase of Fusarium oxysporum was recorded under treatment with either propanolic or ethanolic extracts. There was suppression in the degree of infectivity such as the number of rotted seeds, wilting, brown discoloration of Phaseolus seedlings presoaked in either of the two propolis extracts compared to infected plants with more reduction individually in case of propanolic extract over that of ethanolic one.
- Published
- 2021
4. Efficacy of Alternaria alternate NMK1 Secondary Metabolites against some Seed-borne Fungi
- Author
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R. S. Yousef and Neveen M. Khalil
- Subjects
Penicillium griseofulvum ,Ecology ,biology ,Aspergillus niger ,food and beverages ,Aspergillus flavus ,Cell Biology ,Plant Science ,biology.organism_classification ,Antimicrobial ,Alternaria alternata ,Comet assay ,Acetic acid ,chemistry.chemical_compound ,chemistry ,Genetics ,Gas chromatography ,Food science ,Ecology, Evolution, Behavior and Systematics ,Biotechnology - Abstract
AN AGRICULTURAL soil was used to isolate Alternaria alternata. It was molecularly identified and was given an accession number MN645469 at the National Center for Biotechnology Information (NCBI) and a strain identifier to be Alternaria alternata strain NMK1. Four fractions were collected from the acetic acid extract of its filtrate. Fraction no. 2 showed highest antioxidant activity (71 and 64%, at 200 and 150μg/mL) followed by the crude extract (60 % at 200μg/mL). Safety of using the extracted fractions was tested against the normal human amnion (WISH) cell line. Lowest cytotoxicity values were recorded for fraction no. 2 (19%) followed by the crude extract (28%) at 50μg/mL. Aspergillus flavus, Aspergillus niger and Penicillium griseofulvum exhibited highest relative density percentages (28.4, 30.8 and 24.3%) on their respective isolation seeds; wheat, broad bean and kidney bean. Interestingly, fraction no. 2 caused 100% inhibition of these isolated fungal species at 100μg/mL. The minimum fungicidal concentration (MFC) was estimated to be 50μg/mL against A. flavus and 40μg/mL for A. niger and P. griseofulvum. Generally, subjecting each of the tested isolates to fraction no. 2 led to damage in their DNA as shown by the comet assay. Gas chromatography- mass spectroscopy (GC-MS) profiling of fraction no. 2 showed 12 major compounds with diverse possible biological activities being antiinflammatory, insecticide, anticancer, antineoplastic antifungal, and antimicrobial.
- Published
- 2020
5. Biological Activities of the Alkaloid Quinazoline Extracted from Aspergillus nomius
- Author
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Mohamed Sayed, Neveen M. Khalil, Mohamed R. Ali, and Ahmed AbdElfattah
- Subjects
Aspergillus ,Alcaligenes faecalis ,Gram-negative bacteria ,Ecology ,biology ,Chemistry ,Gram-positive bacteria ,Cell Biology ,Plant Science ,biology.organism_classification ,medicine.disease_cause ,Antimicrobial ,Biochemistry ,Staphylococcus aureus ,Genetics ,medicine ,Candida albicans ,Escherichia coli ,Ecology, Evolution, Behavior and Systematics ,Biotechnology - Abstract
TWENTY FIVE Aspergillus isolates were screened from Giza Governorate and Saint Catherine Protectorate soils in Egypt. The antimicrobial activity of the crude extracts was tested against two Gram positive bacteria (Bacillus subtilis NRRL-B-4219, Staphylococcus aureus ATCC29213), four Gram negative bacteria (Alcaligenes faecalis B-170, Escherichia coli ATCC25922, Klebsiella pneumoniae ATCC10131, Pseudomonas aeruginosa ATCC27953), and one yeast (Candida albicans ATCC10231). The antioxidant activity using free radical scavenging model was assayed for the crude extracts. The antitumor activity for all of crude extracts was determined against HCT116 (Colon carcinoma cell line), HEPG2 (Liver carcinoma cell line), and MCF-7 (Breast carcinoma cell line). Aspergillus nomius was the most potent fungal species accordingly, it was chosen for bioactivity assay. Identification of this species was further confirmed at the molecular level based on nuclear ribosomal DNA 18s identities. An accession number, LC199488, was given at the DDBJ GenBank. The column chromatography of its crude extract yielded five distinguished fractions. The biological (antimicrobial, antioxidant and antitumor) activities of these fractions were assayed. Fraction B proved to be of most potential. HPLC analysis of this fraction showed that there was a sharp and clear peak at about 18.1 min. This denoted the presence of an active compound. The compound at this peak was purified and its structure was elucidated via 1HNMR and 13CNMR spectroscopy. It was concluded that it would be 1,2,3,9 tetrahydropyrrolo [2,1-b] quinazolin-3-ol.
- Published
- 2017
6. Mutagenic Effect of Gamma Irradiation on Phenotype and Enzyme Activities in Aspergillus niger
- Author
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Neveen M. Khalil, G. Abd El-Hamid, Esmat E. Aly, Heba S. Mostafa, and Abo-El-Soued
- Subjects
chemistry.chemical_classification ,Protease ,Ecology ,biology ,Chemistry ,medicine.medical_treatment ,Aspergillus niger ,Mutant ,Cell Biology ,Plant Science ,Cellulase ,biology.organism_classification ,Microbiology ,Enzyme ,Biochemistry ,Genetics ,biology.protein ,medicine ,Amylase ,Lipase ,Pectinase ,Ecology, Evolution, Behavior and Systematics ,Biotechnology - Abstract
THIS STUDY aimed at investigating the effect of gamma irradiation…… on the phenotypic characters of Aspergillus niger and its impacton the activities of some enzymes such as lipase, protease, cellulase,pectinase and amylase. Two phenotypically different mutants wereobtained after gamma irradiation at doses of 1 and 3 kGy. SEMmicroscopy showed clear morphological changes in conidiophores,conidial heads and spores among all strains. The activities of lipase,protease and cellulase in both mutants become less than that of theparent strain, while, pectinase showed no significant difference amongthe tested strains. Amylase activity was enhanced by gammairradiationin the mutants. The obtained mutants were molecularlycharacterized using RAPD-PCR. The results demonstrated theoccurrence of polymorphic pattern between parent and mutant strainsdue to change in the genetic makeup.
- Published
- 2017
7. Antifungal and anti-mycotoxin efficacy of biogenic silver nanoparticles produced by Fusarium chlamydosporum and Penicillium chrysogenum at non-cytotoxic doses
- Author
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Neveen M. Khalil, Mohamed N. Abd El-Ghany, and Susana Rodriguez-Couto
- Subjects
Ochratoxin A ,Aflatoxin ,Environmental Engineering ,Antifungal Agents ,Silver ,Health, Toxicology and Mutagenesis ,0208 environmental biotechnology ,Metal Nanoparticles ,Aspergillus flavus ,02 engineering and technology ,Microbial Sensitivity Tests ,010501 environmental sciences ,Penicillium chrysogenum ,01 natural sciences ,Silver nanoparticle ,chemistry.chemical_compound ,Minimum inhibitory concentration ,Aflatoxins ,Fusarium ,Microscopy, Electron, Transmission ,Spectroscopy, Fourier Transform Infrared ,Toxicity Tests ,Environmental Chemistry ,Humans ,Mycotoxin ,0105 earth and related environmental sciences ,Aspergillus ochraceus ,biology ,Cell-Free System ,Public Health, Environmental and Occupational Health ,General Medicine ,General Chemistry ,biology.organism_classification ,Pollution ,Ochratoxins ,Dynamic Light Scattering ,020801 environmental engineering ,chemistry ,Melanocytes ,Nuclear chemistry - Abstract
The cell-free culture filtrate (CFF) of the fungi Fusarium chlamydosporum NG30 and Penicillium chrysogenum NG85 was tested to synthesize silver nanoparticles (AgNPs). The synthesized AgNPs were further characterized by means of transmission electron microscopy (TEM), dynamic light scattering (DLS) and Fourier transform infra-red (FTIR) spectroscopy. TEM revealed their spherical shape, homogeneity and a size range between 6 and 26 nm for F. chlamydosporum AgNPs (FAgNPs) and from 9 to 17.5 nm for P. chrysogenum AgNPs (PAgNPs). DLS showed that the diameter of FAgNPs was narrower than that of PAgNPs. FTIR spectroscopy indicated that the functional groups present in the CFF might be responsible for the reduction of silver ions to form stabilized protein-capped AgNPs. In addition, the AgNPs showed notable antifungal activity and potency in thwarting mycotoxin production. Thus, using Aspergillus flavus as a test microorganism the minimum inhibitory concentration (MIC) was 48, 45 and 50 μg/mL for FAgNPs, PAgNPs and the antifungal compound itraconazole, respectively. Also, when testing Aspergillus ochraceus FAgNPs, PAgNPs and itraconazole led to MIC values of 51, 47 and 49 μg/mL, respectively. The statistical MIC values to inhibit completely the total aflatoxin production by A. flavus were 5.9 and 5.6 μg/mL for FAgNPs and PAgNPs, respectively, and to inhibit the ochratoxin A production by A. ochraceus 6.3 and 6.1 μg/mL for FAgNPs and PAgNPs, respectively. The cytotoxicity assay of the AgNPs on human normal melanocytes (HFB 4) revealed a cell survival of 80% and 75% at a concentration of 6 μg/mL for FAgNPs and PAgNPs, respectively.
- Published
- 2018
8. Biological activities of secondary metabolites from Emericella nidulans EGCU 312
- Author
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Emad A. Shalaby, Neveen M. Khalil, Dalia M. I. A. Ali, Ahmed M. Aboul-Enein, and Enas M. Ali
- Subjects
Chromatography ,biology ,Ethyl acetate ,Plant Science ,biology.organism_classification ,medicine.disease_cause ,Antimicrobial ,Microbiology ,Aspergillus fumigatus ,chemistry.chemical_compound ,Minimum inhibitory concentration ,Infectious Diseases ,Emericella ,chemistry ,Staphylococcus aureus ,Lactate dehydrogenase ,medicine ,Escherichia coli - Abstract
The fungus, Emericella nidulans was isolated from soil. The ITS region of 5.8S rRNA of the isolated fungus was amplified and sequenced. E. nidulans EGCU312 was given an accession number: KC511056 in the NCBI GenBank. Twenty one (21) fractions were obtained from the ethyl acetate extract of fungal filtrate. Fraction no. 12 showed the highest antioxidant activity with 81.54% at 200 µg/ml. High anticancer activities (against EACC cell line) ranging between 64.3 and 87.7% at 200 µg/ml, were exhibited by fractions no. 1, 2, 4, 9, 12 and 20. The mode of action of anticancer activity was studied by measuring activities of lactate dehydrogenase (LDH) and caspase-3. Fraction no. 12 gave the highest effect (2249.2 U/l) in LDH released as compared to control cells (1127.7 U/l) and caused a 1.56-fold increase in caspase-3 activity. Interestingly, fraction no. 12 caused 100% inhibition of Staphylococcus aureus and Escherichia coli at 50 µg/ml, and Aspergillus fumigatus at 100 µg/ml. The minimum bactericidal concentrations (MBC) of this fraction were 4 and 10 µg/ml for S. aureus and E. coli, respectively, while the minimum inhibitory concentration (MIC) was 45 µg/ml against A. fumigatus. GC-MS profile of fraction no. 12 showed 21 compounds, six of which, that is, 2-methylbenzylamine, N-heptyl-N-octyl; naphthalene, 2,3,6-trimethyl-; octadecanoic acid, ethyl ester; 1,2-benzenedicarboxylic acid, butyl octyl ester; tributylacetylcitrate; 1,2- and benzenedicarboxylic acid, diisooctyl ester, were of known biological activities. Key words: Emericella nidulans EGCU 312, antioxidant, anticancer, antimicrobial.
- Published
- 2014
9. Biogenic silver nanoparticles by Aspergillus terreus as a powerful nanoweapon against Aspergillus fumigatus
- Author
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Neveen M. Khalil
- Subjects
Fungal protein ,biology ,Chemistry ,Nanoparticle ,Plant Science ,biology.organism_classification ,Microbiology ,Silver nanoparticle ,Aspergillus fumigatus ,Comet assay ,Cell wall ,Infectious Diseases ,Aspergillus terreus ,Fourier transform infrared spectroscopy ,Nuclear chemistry - Abstract
In the past few decades, nanoparticles have emerged as a field in biomedical research. Four isolated Aspergillus species were tested for extracellular synthesis of silver nanoparticles using their cell free filtrate (CFF). Silver nanoparticles of the most potent producer, Aspergillus terreus, were further characterized. Transmission electron microscope (TEM) and atomic force microscope (AFM) revealed their spherical shape, homog eneity and size range between 20 and 140 nm. X-ray diffraction (XRD) showed the crystalline nature of the biogenic silver nanoparticles. Fourier transform infra-red (FTIR) spectroscopic analysis indicated that the coordination behaviors between amino groups of the secreted fungal proteins and other functional groups present in the CFF may be liable for the reduction of silver ions to form stabilized protein-capped silver nanoparticles. They were stable in aqueous solution for four months of storage at room temperature under dark conditions. The biogenic silver nanoparticles showed remarkable antifungal activity against the human pathogenic fungus A. fumigatus. The spore cell wall, plasma membrane and the inner constituents were damaged as shown by TEM. Furthermore, comet assay proved high breakage of DNA. Key words: Silver nanoparticles, biosynthesis, fungi, antifungal, comet assay.
- Published
- 2013
10. Keratinolytic activity of purified alkaline keratinase produced by Scopulariopsis brevicaulis (Sacc.) and its amino acids profile
- Author
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Eman Fathi Sharaf and Neveen M. Khalil
- Subjects
Gel electrophoresis ,Alanine ,chemistry.chemical_classification ,biology ,Keratinase ,Agricultural and Biological Sciences(all) ,Fungi ,Keratinolytic activity ,Amino acid ,chemistry ,Biochemistry ,Valine ,SDS–PAGE ,Glycine ,biology.protein ,Keratinaceous materials ,Amino acids ,Original Article ,Leucine ,General Agricultural and Biological Sciences ,Polyacrylamide gel electrophoresis ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) ,ComputingMilieux_MISCELLANEOUS - Abstract
Sodium dodecyl sulfate–polyacrlyamide gel electrophoresis (SDS–PAGE) was used to assess the purity and molecular weight of the previously purified alkaline keratinase enzyme of Scopulariopsis brevicaulis. The enzyme was homogenous, as seen by a single band of protein, and had an apparent molecular weight of 28.5kDa. Amino acid profile of the purified keratinase revealed that it was composed of 14 different amino acids with high proportions of glutamic acid (20.86%), alanine (14.52%), glycine (14.21%), leucine (8.59%) and serine (7.81%). The enzyme contained moderate amounts of valine (6.01%), threonine (5.58%) and phenyl alanine (5.22%). The purified enzyme of S. brevicaulis exerted a potent keratinolytic activity and was capable to hydrolyze different keratinaceous materials with highest activity on chicken feathers followed by human nails and human hair.
- Published
- 2011
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11. Synthesis, characterization and antimicrobial activity of poly (N-vinyl imidazole) grafted carboxymethyl chitosan
- Author
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Magdy W. Sabaa, Neveen M. Khalil, Soliman M. Abd El Latif, Nadia A. Mohamed, and Riham R. Mohamed
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Aqueous solution ,Polymers and Plastics ,Organic Chemistry ,technology, industry, and agriculture ,macromolecular substances ,Grafting ,carbohydrates (lipids) ,chemistry.chemical_compound ,Monomer ,chemistry ,Yield (chemistry) ,Polymer chemistry ,Materials Chemistry ,Imidazole ,Solubility ,Antibacterial activity ,Antibacterial agent - Abstract
Poly ( N -vinyl imidazole) (PNVI) has been grafted onto carboxymethyl chitosan in aqueous solution using potassium persulphate (KPS) as initiator. The effect of the monomer and initiator concentration, the reaction temperature and time on the grafting yield have been investigated. The maximum grafting yield was achieved at [KPS] = 8 × 10 −2 mol/L, [M] = 1 mol/L at reaction temperature = 60 °C within reaction time = 2.5 h. The grafted products were characterized by FTIR, elemental analysis, SEM photographs, solubility tests, thermal analysis and antibacterial activity. Grafted products have improved the antimicrobial activity of carboxymethyl chitosan.
- Published
- 2010
12. Biodegradation of some polycyclic aromatic hydrocarbons by Aspergillus terreus
- Author
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Mohamed I. Ali, Neveen M. Khalil, and Mohamed N. Abd El-Ghany
- Subjects
Laccase ,Anthracene ,biology ,Plant Science ,Lignin peroxidase ,Biodegradation ,biology.organism_classification ,Microbiology ,chemistry.chemical_compound ,Infectious Diseases ,chemistry ,Manganese peroxidase ,Environmental chemistry ,Soil water ,Aspergillus terreus ,Naphthalene - Abstract
In our search for new fungal isolates capable of degrading polycyclic aromatic hydrocarbons (PAHs) in soil, twenty one fungal isolates were recovered from Orman Garden, Wadi Degla Protectorate and benzene station soils. All tested fungi exhibited lignin peroxidase and manganese peroxidase activities in solid as well as in liquid cultures. However, laccase was detected in low amounts by some of the tested fungal isolates. Accordingly, laccase was eliminated from further work. Aspergillus terreus was superior in ligninolytic enzyme production. Hence, it was chosen for the following studies. The statistical optimum temperatures for lignin peroxidase and manganese peroxidase production by A. terreus were 33.6 and 33.1°C, respectively. Meanwhile lignin peroxidase and manganese peroxidase yields were maximal at pH 4.1 and 5.8, respectively. Highest ligninolytic enzyme secretions were established on D-glucose and sodium nitrate. An experiment to study biodegradation of PAHs in soil was conducted. A. terreus was able to degrade 98.5% of naphthalene and 91% of anthracene in soil models. Key words: Biodegradation, fungi, polycyclic aromatic hydrocarbons (PAHs) Ligninolytic enzymes, soil model
- Published
- 2012
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