Ashraf Essa | Fayoum University (original) (raw)

Papers by Ashraf Essa

Cyanobacteria are a diverse group of prokaryotes that are spread worldwide. They improve the grow... more Cyanobacteria are a diverse group of prokaryotes that are spread worldwide. They improve the growth and development of the plants they share their vicinity via releasing various biologically active substances. The effect of the exudates of the cyanobacterial strains; Anabaena oryzae, Nostoc ellipsosporum and Synechococcus sp. on the percent of seed germination and the seedling growth criteria of Sorghum durra and Helianthus annuus was investigated in this study. A marked promotion in the seed germination of Sorghum durra was recorded with Anabaena oryzae and Synechococcus sp. while the three culture filtrates demonstrated a negative consequence with Helianthus annuus. At the same time, the seedling growth criteria of the treated plants were highly significantly enhanced especially with Anabaena oryzae. Also, A clear augmentation in the activity of the antioxidant enzymes; catalase, peroxidase and polyphenol oxidase was recorded in the treated plants. Analysis of Anabaena oryzae exud...

Biocontrol Science and Technology, 2017

The antifungal potentialities of three endophytic bacterial strains, Stenotrophomonas maltophila ... more The antifungal potentialities of three endophytic bacterial strains, Stenotrophomonas maltophila H8 (Xanthomonadales: Xanthomonadaceae), Pseudomonas aeruginosa H40 (Pseudomonadales: Pseudomonadaceae), and Bacillus subtilis H18 (Bacillales: Bacillaceae) were evaluated against the phytopathogenic fungus Rhizoctonia solani in cotton seedlings under greenhouse conditions. The bacterial strains were applied as a soil drench or talc-based bioformulation in R. solani infested soil and non-infested soil. Results indicated that the soil drench treatment was more efficient than talc-based bioformulation. A significant increase of seed emergence and seedling survival with a clear reduction of disease severity was achieved with the endophytic bacterial treatments. At the same time, the fresh weight, dry weight, shoot length and root length of the treated plants were markedly enhanced. Moreover, there was an apparent induction of the antioxidant enzymes (peroxidase, polyphenol oxidase, and catalase) of the treated seedlings. Gas chromatography-mass spectrometry revealed the presence of various bioactive compounds in the bacterial supernatant. The antagonistic activity of the bacterial strains against R. solani was attributed to their capability to produce a broad spectrum 3 of antifungal compounds in addition to bioactive molecules that can trigger the systemic resistance in the infected seedlings.

THE EGYPTIAN JOURNAL OF EXPERIMENTAL BIOLOGY (Botany), 2021

Egyptian Journal of Botany, Sep 30, 2016

N ACCOUNT of incessant human activities, copper is ……...accumulated in the environment at elevate... more N ACCOUNT of incessant human activities, copper is ……...accumulated in the environment at elevated concentrations that induce harmful influences on all kinds of living organisms. An oxic bioreactor was employed to transform copper ions into copper particles using volatile metabolites of Escherichia coli culture. SEM and EDX analysis of the transformed copper showed the formation of elongated particles with 1-5 µm in length comprising of copper, sulfur, carbon, oxygen and nitrogen elements. Mung bean seeds and barley grains exposed to ionic copper demonstrated low germination and apparent decline of seedlings growth parameters while higher germination and growth rates were recorded with those treated with copper particles. At the same time, an enhanced POD activity was noticed with all Cu treatments, CAT activity seemed to be induced in response to ionic Cu only meanwhile APX activity was markedly affected with both types of Cu. Furthermore, seedlings subjected to Cu particles showed higher protein contents. Toxicity reduction of copper treated with E. coli volatiles was ascribed to the decrease of the mobile copper concentration as a result of interaction with vaporized chelators that reduce bioavailability of copper.

Polish Journal of Environmental Studies, 2019

Excessive exposure to heavy metals is known to induce deleterious effects on health. The monitori... more Excessive exposure to heavy metals is known to induce deleterious effects on health. The monitoring of heavy metals in sewage is important for examining environmental pollution induced by treated sewage effluent (TSE). In the current investigation, heavy metals concentrations of TSE of two sewage treatment plants in the Jazan region of KSA were monitored using a Perkin Elmer Optima 7000 DV inductively coupled plasma optical emission spectrometer (ICP-OES). The heavy metals concentrations were below the permissible limit, according to the Ministry of Water and Electricity (MWE) standards of Saudi authorities, except for magnesium and mercury. TSE from the treatment plants was subjected to additional treatment using the volatile organic compounds (VOCs) of the bacterial strain Citrobacter freundii. A marked reduction of the heavy metals concentrations of the bacterial-treated TSE was recorded. The impact of the bacterial-treated TSE on germination indices of Vigna radiata and Hordeum vulgare was investigated. The seedlings irrigated with the bacterial-treated TSE recorded a clear enhancement of growth parameters. Moreover, the level of accumulated heavy metals in seedlings irrigated with bacterial-treated TSE was reduced compared with those irrigated with untreated TSE. The current study clarified that the level of heavy metals in TSE could be markedly reduced via the application of bacterial VOCs and hence it can be used as a water resource for agricultural purposes.

THE EGYPTIAN JOURNAL OF EXPERIMENTAL BIOLOGY (Botany), 2018

Domestic wastewater is considered a favorable environment for the survival of broad arrays of mic... more Domestic wastewater is considered a favorable environment for the survival of broad arrays of microorganisms. The current study aimed to characterize the bacteria isolated from two domestic wastewater treatment plants in Jazan, KSA. Morphological and biochemical tests were used to identify the bacterial isolates. Moreover, the antibiotic susceptibility pattern of the bacteria isolates was studied using disc diffusion method. The enteric Gram-negative Enterobacteriaceae were identified as Citrobacter freundii, Pantoea sp., Serratia liquefaciens, Serratia odorifera, Proteus vulgaris, Rahnella aquatilis, Enterobacter sp., Escherichia coli, and Enterobacter cloacae. Simultaneously, non-enteric Gram-negative bacilli were identified as Sphingomonas paucimobilis, Pseudomonas putida, Pseudomonas aeruginosa, Aeromonas sobria, Chryseomonas luteola, and Pasteurella aerogenes. Also, the Gram-positive isolates were identified as Staphylococcus xylosus, Kocuria kristinae and Staphylococcus epidermidis. At the same time, a high level of resistance against Ampicillin/Sulbactam (94.5%) was observed while the recorded percentage of resistance against trimethoprime/sulphamethoxoazole, ticarcillin, imipenen, piperacillin, colistin, cefoxitin and cefepime were 67%, 62%, 22.2%, 33.3%, 22.2%, 83.3% and 38.9% respectively. This study highlighted the existence of multiple antibiotic resistant strains in the tested sewage wastewater that could be attributed to the disproportionate use of antibiotics for human and animal diseases.

Journal of basic microbiology, 2018

Microorganisms can modify the chemical and physical characters of metals leading to an alteration... more Microorganisms can modify the chemical and physical characters of metals leading to an alteration in their speciation, mobility, and toxicity. Aqueous heavy metals solutions (Hg, Cd, Pb, Ag, Cu, and Zn) were treated with the volatile metabolic products (VMPs) of Escherichia coli Z3 for 24 h using aerobic bioreactor. The effect of the metals treated with VMPs in comparison to the untreated metals on the growth of E. coli S1 and Staphylococcus aureus S2 (local isolates) was examined. Moreover, the toxic properties of the treated and untreated metals were monitored using minimum inhibitory concentration assay. A marked reduction of the treated metals toxicity was recorded in comparison to the untreated metals. Scanning electron microscopy and energy dispersive X-ray analysis revealed the formation of metal particles in the treated metal solutions. In addition to heavy metals at variable ratios, these particles consisted of carbon, oxygen, sulfur, nitrogen elements. The inhibition of me...

Journal of Pure and Applied Microbiology, 2017

The capability of thermophilic microorganisms to flourish at high temperatures makes their enzyme... more The capability of thermophilic microorganisms to flourish at high temperatures makes their enzyme systems ideal for various biotechnological applications. Based on the proteolytic and amylolytic activities, two thermophilic bacteria were isolated from hot springs in Jazan, Saudi Arabia. The antibiotic and heavy metals susceptibility patterns of the bacterial isolates were performed. According to the metabolic fingerprint, the bacterial isolates were identified as Brevibacterium linens and Bacillus subtilis. Moreover, the impact of temperature, substrate concentration, and some metal ions on the production of proteases and amylases from the bacterial strains was investigated. The maximum protease production was achieved at 50°C while the greatest amylase production was recorded at 30°C for both strains at a constant pH of 7.5. The highest enzyme production was recorded at 5% skimmed milk for protease of B. linens and 10% for B. subtilis while 0.6% starch was the optimum substrate concentration of amylase production of the two strains. Furthermore, Ca 2+ showed a simulative influence on protease production from the two strains whereas Mg 2+ and Mn 2+ demonstrated minor effect. On the other hand, Ca 2+ , Mg 2+ and Mn 2+ demonstrated a positive effect on the amylase production from both strains.

BMC Microbiology, 2016

Background: Biodeterioration of historic monuments and stone works by microorganisms takes place ... more Background: Biodeterioration of historic monuments and stone works by microorganisms takes place as a result of biofilm production and secretion of organic compounds that negatively affect on the stone matrix. Methods: Copper nanoparticles (CuNPs) were prepared biologically using the headspace gases generated by the bacterial culture Escherichia coli Z1. The antimicrobial activity of CuNPs was evaluated against the bacterial strains Bacillus subtilis, Micrococcus luteus, Streptomyces parvulus, Escherichia coli, Pseudomonas aeruginosa as well as some fungal strains Aspergillus niger, Aspergillus flavus, Penicillium chrysogenum, Fusarium solani and Alternaria solani. Results: Biological CuNPs demonstrated antibacterial and antifungal activities higher than those of the untreated copper sulfate. At the same time, limestone and sandstone blocks treated with consolidation polymers functionalized with CuNPs recorded apparent antimicrobial activity against E. coli, S. parvulus and B. subtilis in addition to an improvement in the physical and mechanical characters of the treated stones. Furthermore, the elemental composition of CuNPs was elucidated using electron dispersive x-ray system connected with the scanning electron microscope. Conclusion: Consolidation polymers impregnated with CuNPs could be used to restrain microbial deterioration in addition to the refinement of physico-mechanical behavior of the historic stones.

Soil salinity has a great impact on decreasing yield potentials of the cultivated crops. The effe... more Soil salinity has a great impact on decreasing yield potentials of the cultivated crops. The effect of presoaking Zea mays grains in the crude extract of the halotolerant alga Dunaliella bardawil on growth and some metabolic activities of salinized plants was investigated in this study. The Pre-soaking treatment demonstrated a highly significant enhancement in the percentage of seed germination. Moreover, the growth parameters of the pretreated plants were improved at hyposalinity stress conditions comparing with untreated ones. A huge augmentation in the soluble carbohydrates, polyols, free amino acids and proline contents was recorded with the pretreated plants at hypersaline stress conditions. GC-MS analysis identified some bioactive molecules in the algal extract such as nicotinamide, xanthine, dihydroxyphenylglycol and linalool that could potentially participate in the alleviation of the salinity stress. Abstract Asian Journal of Biological and Life Sciences Original Research

Asian Pacific Journal of Tropical Biomedicine, 2015

To investigate the effect of intra-peritoneal injection of purified exudates of axenic Spirulina ... more To investigate the effect of intra-peritoneal injection of purified exudates of axenic Spirulina platensis on the mammalian endocrine and nervous systems. Methods: The intra-peritoneal injection of the cyanobacterial exudates in mice was applied. Sex hormonal levels of testosterone and progesterone were measured using radioimmunoassay while the follicular stimulating hormone and luteinizing hormone were evaluated by direct chemiluminescence. In addition, superoxide dismutase, catalase and glutathione peroxidase were monitored in the hippocampus region using spectrophotometric method. The levels of the hippocampal monoamines, dopamine, noradrenaline and serotonin were analyzed by high performance liquid chromatography while the acetyl choline neurotransmitter was measured by colorimetric method using choline/ acetylcholine assay kit. Results: A sharp disruption in the sex hormones levels of testosterone, progesterone, follicular stimulating hormone and luteinizing hormone was demonstrated in the serum of the treated mice. At the same time, a significant reduction in the endogenous antioxidant defense enzymes, superoxide dismutase, catalase and glutathione peroxidase was observed in the hippocampus region of the injected mice. Moreover, levels of dopamine, noradrenaline, serotonin and acetyl choline neurotransmitter in the same region were significantly affected as a result of the treatment with Spirulina filtrate. The gas chromatography-mass spectrometer and liquid chromatography mass spectrometry/mass spectrometry analysis showed the presence of some sterol-like compounds in the cyanobacterial filtrate. Conclusions: This study demonstrated the capability of Spirulina to release detrimental bioactive metabolites into their surrounding that can disrupt the mammalian endocrine and nervous systems.

International Biodeterioration & Biodegradation, 2014

ABSTRACT Abstract The inhabitation of microorganisms and their subsequent interaction with minera... more ABSTRACT Abstract The inhabitation of microorganisms and their subsequent interaction with mineral matrix of the stone substrate under varied environmental conditions encourages deterioration of stones leading to the loss of strength, durability and aesthetic. This study highlighted the synthesis of nanosilver particles (AgNPs) using the biogenic volatiles of the bacterial strain Nesterenkonia halobia. The antimicrobial activities of AgNPs were evaluated against the gram positive bacterial strain Streptomyces parvullus and fungal strain Apergillus niger. Furthermore, the silver particles were mixed with two types of consolidation polymers and were used to coat the external surfaces of sandstone and limestone blocks. The stones treated with silicon polymer loaded with AgNPs showed an elevated antimicrobial potentiality against A. niger and S. parvullus. Scan electron microscope (SEM) and electron dispersive X-ray spectroscopy (EDX) analysis of treated stones demonstrated the existence of nano-composite structures containing the elemental silver. Polymers functionalized with AgNPs can be used not only as potent biocides but also for the consolidation of the historic monuments and artifacts. Keywords Biogenic volatiles; Nanosilver; Antibacterial; Antifungal; Polymers

Journal of Applied Microbiology, 2013

This study investigated the effect of some cyanobacterial exudates on the level of sex hormones i... more This study investigated the effect of some cyanobacterial exudates on the level of sex hormones in a mammalian model and to identify the molecules that could act as endocrine disruptor. In this study, the cytotoxicity of purified exudates of some axenic cyanobacterial cultures (Nostoc ellipsosporum, Nostoc muscorum, Anabaena oryzae & Anabaena. sp.) was evaluated against normal melanocyte cell line (HFB4). The intraperitoneal injection of the cyanobacterial exudates demonstrated a marked disturbance in the serum level of testosterone, progesterone, follicular stimulating hormone (FSH) and luteinizing hormone (LH) of male mice. GC-MS and LC-MS/MS analysis showed the presence of some sterol-like compounds in the cyanobacterial filtrates. This work demonstrated that the nontoxic cyanobacterial species have the ability to produce some bioactive compounds into their surroundings that can disrupt the mammalian reproductive hormones. The cyanobacterial extracellular bioactive molecules can affect on the production of the sex hormones via positive and negative feedback and may be a risk to human beings.

European Food Research and Technology, 2006

The present study was conducted to evaluate the antioxidant and antimicrobial properties of metha... more The present study was conducted to evaluate the antioxidant and antimicrobial properties of methanol (100 and 80% aqueous) extracts of pummelo fruits albedo (Citrus grandis Osbeck). The antioxidant and antibacterial activity for crude extracts and isolated compounds were evaluated using free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) and Paper disc diffusion method. A 100% Methanol (MeOH) extract was steeped in water at different pH levels and partitioned with ethyl acetate (EtOAc) to give basic, acidic, neutral, and phenolic fractions. The neutral extract was found to possess maximum antioxidant and antibacterial activity. Thereafter, neutral extract was carried out on a silica gel column and eluted with hexane:EtOAc:acetone and preparative TLC (PTLC) to give oil buntan compound, linoleic acid methyl ester, β-sitosterol, sigmasterol, limonin, nomilin and meranzin hydrate were isolated. While, 80% MeOH extract was fractionated also using a silica gel column and PTLC to give isomeranzin hydrate, p-coumaric acid and caffeic acid compound. The extract concentration providing 50% inhibition (IC 50) was as follows; oil buntan compound 95 µg/mL, caffeic acid 45 µg/mL, p-coumaric acid 105 µg/mL, limonin + nomilin (mixture) 135 µg/mL was lower than that of synthetic antioxidant butylated hydroxyanisole (BHA) 40 µg/mL. The inhibitory zone (mm) of bacteria tested was 2.9-4.1 mm caffeic acid and 11.6-15.1 mm p-coumaric acid.

Environmental Technology, 2002

Resistance to Cr(VI) is usually associated with its cellular exclusion, precluding enrichment tec... more Resistance to Cr(VI) is usually associated with its cellular exclusion, precluding enrichment techniques for the isolation of organisms accumulating Cr(VI) via bioreduction to insoluble Cr(III). A technique was developed to screen for potential Cr(VI) reduction in approx. 2000 isolates from a coastal environment, based on the non-specific reduction of selenite and tellurite to Se0 and Te0, and reduction of tetrazolium blue to insoluble blue formazan. The most promising strains were further screened in liquid culture, giving three, which were identified by 16S rRNA sequence analysis as Bacillus pumilus, Exiguobacterium aurantiacum and Pseudomonas synxantha, all of which reduced 100 microM Cr(VI) anaerobically, without growth. The respective removal of Cr(VI) was 90% and 80% by B. pumilus and E. aurantiacum after 48 h and 80% and by P. synxantha after 192 h. With the gram positive strains Cr(VI) promoted loss of flagella and, in the case of B. pumilus, lysis of some cells, but Cr was deposited as an exocellular precipitate which was identified as containing Cr and P using energy dispersive X-ray microanalysis (EDAX). This prompted the testing of Citrobacter sp. N14 (subsequently re-assigned by 16S rRNA sequence analysis and biochemical studies as a strain of Serratia) which bioprecipitates metal cation phosphates via enzymatically-liberated phosphate. This strain reduced Cr(VI) at a rate comparable to that of P. synxantha but Cr(III) was not bioprecipitated where La(III) was removed as LaPO4, even though a similar amount of phosphate was produced in the presence of Cr(III). Since B. pumilus removed most of the Cr(VI), with the formation of cell-bound CrPO4 implicated, this suggests that this strain could have future bioprocess potential.

Biochemical Society Transactions, 2002

Mercury is one of the most toxic heavy metals, and has significant industrial and agricultural us... more Mercury is one of the most toxic heavy metals, and has significant industrial and agricultural uses. These uses have led to severe localized mercury pollution. Mercury volatilization after its reduction to the metallic form by mercury-resistant bacteria has been reported as a mechanism for mercury bioremediation [Brunke, Deckwer, Frischmuth, Horn, Lunsdorf, Rhode, Rohricht, Timmis and Weppen (1993) FEMS Microbiol. Rev. 11, 145–152; von Canstein, Timmis, Deckwer and Wagner-Dobler (1999) Appl. Environ. Microbiol. 65, 5279–5284]. The reduction/volatilization system requires to be studied further, in order to eliminate the escape of the metallic mercury into the environment. Recently we have demonstrated three different mechanisms for mercury detoxification in one organism, Klebsiella pneumoniae M426, which may increase the capture efficiency of mercury.

African Journal of Microbiology Research, 2012

Active resistance to the mercuric ion is widely distributed in environmental microbes and results... more Active resistance to the mercuric ion is widely distributed in environmental microbes and results from the action of mercuric reductase. Five mercury resistant bacteria: Escherichia coli Z1, Escherichia coli Z3, Pseudomonas putida Z2, Serratia marcescens Z4 and Xanthomonas sp. Z5 were isolated and identified from sludge sample. The presence of mercury resistance determinants was screened by PCR using merA-specific primers. Based on the analysis of merA amplicons, high similarity was recorded between the merA region of the strains P. putida Z2 and Xanthomonas sp. Z5 with those of Tn5053; while the merA of E. coli Z1 was analogous to those of Tn21. In case of the bacterial strains E. coli Z3 and S. marcescens Z4 a great matching was obtained between their merA and those of Tn5036. The effect of mercury stress upon the structure of mercury reducing biofilm at the species level and the type of mercury resistance determinants was studied in a continuous bioreactor. Community analysis suggested that the bacterial strain E. coli Z3 containing Tn5036-like determinant is the well adapted strain that tolerated elevated levels of mercury whereas the other strains showed a less fitness under these extreme conditions.

AFRICAN JOURNAL OF BIOTECHNOLOGY, 2012

Heavy metals pollution is nowadays one of the most important environmental concerns. This paper i... more Heavy metals pollution is nowadays one of the most important environmental concerns. This paper illustrates the employment of the biogenic volatile compounds generated during the aerobic growth of activated sludge on raw domestic wastewater for heavy metals removal. Most of the tested metals even as individual or mixed metal species (Co, Cu, Cd, Fe, Hg, Ni, Mn, Pb and Zn) were potentially transformed into insoluble precipitates and then separated out of their solutions. The Fourier-transform infrared (FTIR) analysis has identified some organosulfur groups (thiol, disulfide and thiocarbonyl), in addition to amine group in the metal precipitates. This study highlighted the application of the microbial volatile metabolites for heavy metals bioremediation in a powerful, cost effective and eco-friendly bioprocess.

Chemosphere, 2009

Although cadusafos, an aliphatic organophosphorus (OP) insecticide, is not approved by the Europe... more Although cadusafos, an aliphatic organophosphorus (OP) insecticide, is not approved by the European commission, it is used in several countries and sometimes detected as a residue in soils and agricultural products. In this study, two cadusafos-degrading Sphingobium sp. strains, K22212 and Cam5-1, were isolated and characterized for use as detoxifying agents of the insecticide. Both strains degraded 100 mg L −1 of cadusafos in mineral medium within 12 h through a common metabolite, which was supposed to be dimerized thiophosphates based on its molecular weight. Degradation of cadusafos increased cell growth for Cam5-1 but not for K22212. K2212 and Cam5-1 degraded cadusafos in soil (15 mg kg −1 dry soil) within 5 and 2 days, respectively. Both strains also degraded ethoprophos, phenthoate and phorate but not chlorpyrifos and diazinon, indicating that they are specialized for degradation of OP insecticides with at least one single bond connecting phosphorus and sulfur atoms (PeS bond). For both strains, the degradation rate was the largest for ethoprophos, followed by cadusafos, phenthoate, and phorate. Our results indicate that these bacterial strains are effective degraders of OP insecticides with PeS bonds, and in particular, Cam5-1 is more promising for removal of the OP insecticides in soils.