Publications by authors named "Mohamed A Ramadan"

9 Publications

  • Page 1 of 1

Inhibition of acetic acid-induced colitis in rats by new Pediococcus acidilactici strains, vitamin producers recovered from human gut microbiota.

PLoS One 2021 26;16(7):e0255092. Epub 2021 Jul 26.

Microbiology and Immunology Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt.

Our aim was to isolate, identify and characterize probiotic bacteria as vitamin producers in particular B2 and B9. 150 human fecal samples were collected and used for isolation of vitamin producers-probiotics. 49 isolates were chosen for screening their genome by PCR for the presence of riboflavin and folic acid genes. As a result, three isolates were selected and their production of the B2 and B9 were confirmed by HPLC. The three isolates were identified on species level by sequencing their 16S rRNA gene which showed 100% identical to strains of Pediococcus acidilactici. Thus, they were named as P. acidilactici WNYM01, P. acidilactici WNYM02, P. acidilactici WNYM03 and submitted to the Genbank database with accession numbers. They met the probiotic criteria by expressing 90-95% survival rate at pH (2.0-9.0) and bile salt up to 2% for 3 h in addition to their antimicrobial activity against gram positive and negative microorganisms. They also showed no hemolytic activity and common pattern for antibiotic susceptibility. Our three strains were tested individually or in mixture in vivo on rat colitis model compared to ulcerative group. The strains were administrated orally to rats in daily dose containing CFU 109 for 14 days then followed by induction of colitis using acetic acid then the oral administration was continued for more four days. The histology results, the anti-inflammatory and anti-oxidative stress biomarkers showed the protective role of the strains compared to the ulcerative group. As a conclusion, we introduce novel three probiotic candidates for pharmaceutical preparations and health applications.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0255092PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8312973PMC
July 2021

Indole Derivatives Obtained from Egyptian sp. Soil Isolates Exhibit Antivirulence Activities against Uropathogenic .

Antibiotics (Basel) 2021 Mar 29;10(4). Epub 2021 Mar 29.

Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo 11562, Egypt.

is a frequent cause of catheter associated urinary tract infections (CAUTIs). Several virulence factors contribute to its pathogenesis, but swarming motility, biofilm formation, and urease activity are considered the hallmarks. The increased prevalence in antibiotic resistance among uropathogens is alarming and requires searching for new treatment alternatives. With this in mind, our study aims to investigate antivirulence activity of indole derivatives against multidrug resistant isolates. Ethyl acetate (EtOAc) extracts from sp. (rhizobacterium), isolated from Egyptian soil samples were tested for their ability to antagonize the virulence capacity and biofilm activity of uropathogens. Extracts of two sp. isolates (coded Zch127 and Cbg70) showed the highest antivirulence activities against . The two promising rhizobacteria Zch127 and Cbg70 were isolated from soil surrounding: (Zucchini) and (Cabbage), respectively. Sub-minimum inhibitory concentrations (Sub-MICs) of the two extracts showed potent antibiofilm activity with significant biofilm reduction of ten clinical isolates (-value < 0.05) in a dose-dependent manner. Interestingly, the Zch127 extract showed anti-urease, anti-swarming and anti-swimming activity against the tested strains. Indole derivatives identified represented key components of indole pyruvate, indole acetamide pathways; involved in the synthesis of indole acetic acid. Additional compounds for indole acetonitrile pathway were detected in the Zch127 extract which showed higher antivirulence activity. Accordingly, the findings of the current study model the feasibility of using these extracts as promising antivirulence agent against the uropathogens and as potential therapy for treatment of urinary tract infections (UTIs).
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http://dx.doi.org/10.3390/antibiotics10040363DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8065651PMC
March 2021

Alginate, gelatin, and carboxymethyl cellulose coated nonwoven fabrics containing antimicrobial AgNPs for skin wound healing in rats.

Int J Biol Macromol 2021 Mar 20;173:203-210. Epub 2021 Jan 20.

UNC Eshelman School of Pharmacy, Chapel Hill, NC 27599, USA. Electronic address:

Nonwoven fabrics containing silver nanoparticles (AgNPs) are widely utilized to assist management of infected wounds and those at risk of infection. However, such materials have varied responses due to their chemical nature. Herein we investigated the correlation between the concentration of AgNPs taken up by nonwoven viscose material and antibacterial activity in a simulated wound fluid model against two bacterial models (i.e., Escherichia coli and Staphylococcus aureus). Thereafter, the developed nonwoven viscose containing AgNPs were independently coated with two polyacid carbohydrate polymers (i.e., carboxymethyl chitosan (CMCs), alginate (ALG)), and gelatin (GEL) protein in order to study their influence on the physical and biological attributes in vitro and in vivo. Intensive characterizations were utilized to monitor the physicochemical features of the developed nonwoven viscose. The results demonstrated that higher concentrations of AgNPs were taken up by viscose fabric whilewhile increasing AgNPs in the colloidal solution during padding process. Overall, the treated nonwoven fabric with and without polymers' coatings showed remarkable antibacterial activity against two bacterial models in vitro. As well as they achieved high and speed wound recovery in rats which was almost similar to commercial dermazin treatment. Therefore, it validates excellent nonwoven dressing clinically relevant to the wound type and condition.
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http://dx.doi.org/10.1016/j.ijbiomac.2021.01.123DOI Listing
March 2021

The biosurfactants iturin, lichenysin and surfactin, from vaginally isolated lactobacilli, prevent biofilm formation by pathogenic Candida.

FEMS Microbiol Lett 2020 08;367(15)

Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt.

Lactic acid bacteria (LAB), particularly lactobacilli, are major components of the vaginal microbiota. Lactobacilli are facultative anaerobes forming a critical line of defense against pathogenic microorganisms, including those forming biofilms, such as Candida spp. This study aimed to investigate the anti-adhesion capabilities of vaginal Lactobacillus isolates against biofilms formed by pathogenic Candida species. When the extracellular biosurfactant activities of culture supernatants from 120 Lactobacillus isolates were evaluated by the oil-spreading method, clear spreading zones were recognized. Biofilm formation was quantified by the crystal violet plate assay, and different isolates exhibited anti-adhesion activity that ranged from 65.6to 74.4% inhibition against Candida spp. biofilms. Liquid chromatography high-resolution electrospray ionization mass spectrometry (LC-HRESIMS) identified biosurfactants, extracted from three representative Lactobacillus isolates, as surfactin, iturin and lichenysin. Finally, the distribution of representative genes from six different biosynthetic clusters, related to the production of different biosurfactants, was investigated by the polymerase chain reaction. In conclusion, surfactin, iturin and lichenysin were identified for the first time in vaginal Lactobacillus spp. These biosurfactants, which showed strong anti-adherence activity may be used as promising antibiofilm agents in equipment care to prevent vaginal infections by pathogenic Candida spp. with the prospect of reducing nosocomial infections.
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http://dx.doi.org/10.1093/femsle/fnaa126DOI Listing
August 2020

Error-prone PCR mutagenesis and reverse bacterial two-hybrid screening identify a mutation in asparagine 53 of the Staphylococcus aureus ESAT6-like component EsxB that perturbs interaction with EsxD.

Folia Microbiol (Praha) 2018 Jul 22;63(4):483-492. Epub 2018 Feb 22.

Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt.

The ESAT6-like Secretion System (ESS) of the human pathogen Staphylococcus aureus secretes heterodimeric virulence effectors such as EsxB and EsxD. To gain insights into the nature of EsxB-EsxD interaction, randomly mutated esxB generated by error-prone PCR was co-transformed together with esxD as adenylate cyclase fusion constructs into cyclase-deficient Escherichia coli, followed by reverse bacterial two-hybrid screening. Three color species were observed: dark blue, light blue, and white (no EsxB-EsxD interaction). The esxB from white colonies was subjected to standard PCR to check for gene signal, followed by SDS-PAGE for variant stability assessment. The gene coding for a stable EsxB variant that perturbed interaction with EsxD was further subjected to DNA sequencing. A single point mutation in esxB at position 157 was identified, leading to an amino acid change from asparagine to aspartic acid at position 53 in the resulting protein. Structural modeling of EsxB reveals that N53 is surface exposed. Whereas N53S substitution by site-directed mutagenesis retained heterodimerization with EsxD, N53A substitution abrogated such interaction. In addition, N53D change in EsxB did not alter interaction with EssG, another soluble component of the ESS pathway, suggesting minimal impact of the N53D substitution on EsxB stability and solubility. Taken together, these data provide new insights into the nature of EsxB-EsxD interaction and offer a systematic approach for in vivo analysis of protein-protein interactions of pathogenic bacteria in non-pathogenic hosts.
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http://dx.doi.org/10.1007/s12223-018-0591-6DOI Listing
July 2018

Androgen receptor antagonists and anti-prostate cancer activities of some newly synthesized substituted fused pyrazolo-, triazolo- and thiazolo-pyrimidine derivatives.

Int J Mol Sci 2014 Nov 24;15(11):21587-602. Epub 2014 Nov 24.

Pharmacology and Toxicology Department, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

A series of substituted pyrazole, triazole and thiazole derivatives (2-13) were synthesized from 1-(naphtho[1,2-d]thiazol-2-yl)hydrazine as starting material and evaluated as androgen receptor antagonists and anti-prostate cancer agents. The newly synthesized compounds showed potent androgen receptor antagonists and anti-prostate cancer activities with low toxicity (lethal dose 50 (LD50)) comparable to Bicalutamide as reference drug. The structures of newly synthesized compounds were confirmed by IR, 1H-NMR, 13C-NMR, and MS spectral data and elemental analysis. The detailed synthesis, spectroscopic data, LD50 values and pharmacological activities of the synthesized compounds are reported.
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http://dx.doi.org/10.3390/ijms151121587DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4264242PMC
November 2014

A Facile One-pot Synthesis and Antimicrobial Activity of Pyrido [2,3-d][1,2,4]triazolo[4,3-a]pyrimidin-5-ones.

Acta Chim Slov 2011 Mar;58(1):87-94

A series of pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidin-5-ones (8) has been synthesised via reaction of 5-substituted-2-thioxo-2,3-dihydro-1H-pyrido[2,3-d]pyrimidin-4-one (3) or its methylthio derivative 4 with hydrazonoyl chlorides 5. Alternative syntheses of products 8 were carried out either by reaction of enaminone 1 with 7-amino-1,3-disubstituted[1,2,4]triazolo[4,3-a]pyrimidin-5-one (10) or via the Japp-Klingemann reaction of compound 13. Both conventional thermal and microwave irradiation techniques were used for synthesis of the target products 8 and a comparative study of these techniques using triethylamine or chitosan, as basic catalysts, was carried out. The mechanisms of the reactions under investigation are discussed. In addition, the antimicrobial activity of the newly synthesized products was evaluated.
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March 2011

Pan-Arab consensus statement on the use of botulinum toxin type A in spasticity management.

Neurosciences (Riyadh) 2007 Oct;12(4):279-81

Department of Neurology, King Faisal Specialist Hospital and Research Center, Riyadh, Kingdom of Saudi Arabia. Tel. +966 (1) 464 7272. Ext. 32772. Fax. +966 (1) 442 4763. E-mail:

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October 2007

The three-dimensional structure of calcium-depleted human C-reactive protein from perfectly twinned crystals.

Acta Crystallogr D Biol Crystallogr 2002 Jun 29;58(Pt 6 Pt 2):992-1001. Epub 2002 May 29.

School of Life Sciences, Keele University, Staffordshire ST5 5BG, England.

C-reactive protein is a member of the pentraxin family of oligomeric serum proteins which has been conserved through evolution, homologues having been found in every species in which they have been sought. Human C-reactive protein (hCRP) is the classical acute-phase reactant produced in large amounts in response to tissue damage and inflammation and is used almost universally as a clinical indicator of infection and inflammation. The role of hCRP in host defence and the calcium-dependent ligand-binding specificity of hCRP for phosphocholine moieties have long been recognized. In order to clarify the structural rearrangements associated with calcium binding, the reported affinity of calcium-depleted hCRP for polycations and other ligands, and the role of calcium in protection against denaturation and proteolysis, the structure of calcium-depleted hCRP has been determined by X-ray crystallography. Crystals of calcium-depleted hCRP are invariably twinned and those suitable for analysis are merohedral type II twins of point group 4 single crystals. The structure has been solved by molecular replacement using the calcium-bound hCRP structure [Shrive et al. (1996), Nature Struct. Biol. 3, 346-354]. It reveals two independent pentamers which form a face-to-face decamer across a dyad near-parallel to the twinning twofold axis. Cycles of intensity deconvolution, density modification (tenfold NCS) and model building, eventually including refinement, give a final R factor of 0.19 (R(free) = 0.20). Despite poor definition in some areas arising from the limited resolution of the data and from the twinning and disorder, the structure reveals the probable mode of twinning and the conformational changes, localized in one of the calcium-binding loops, which accompany calcium binding.
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http://dx.doi.org/10.1107/s0907444902005693DOI Listing
June 2002
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