Publications by authors named "Mohamed I Abou-Dobara"

8 Publications

  • Page 1 of 1

The nucleolar-related protein Dyskerin pseudouridine synthase 1 (DKC1) predicts poor prognosis in breast cancer.

Br J Cancer 2020 11 1;123(10):1543-1552. Epub 2020 Sep 1.

Nottingham Breast Cancer Research Centre, Division of Cancer and Stem Cells, School of Medicine, University of Nottingham Biodiscovery Institute, University Park, Nottingham, UK.

Background: Hypertrophy of the nucleolus is a distinctive cytological feature of malignant cells and corresponds to aggressive behaviour. This study aimed to identify the key gene associated with nucleolar prominence (NP) in breast cancer (BC) and determine its prognostic significance.

Methods: From The Cancer Genome Atlas (TCGA) cohort, digital whole slide images identified cancers having NP served as label and an information theory algorithm was applied to find which mRNA gene best explained NP. Dyskerin Pseudouridine Synthase 1 (DKC1) was identified. DKC1 expression was assessed using mRNA data of Molecular Taxonomy of Breast Cancer International Consortium (METABRIC, n = 1980) and TCGA (n = 855). DKC1 protein expression was assessed using immunohistochemistry in Nottingham BC cohort (n = 943).

Results: Nuclear and nucleolar expressions of DKC1 protein were significantly associated with higher tumour grade (p < 0.0001), high nucleolar score (p < 0.001) and poor Nottingham Prognostic Index (p < 0.0001). High DKC1 expression was associated with shorter BC-specific survival (BCSS). In multivariate analysis, DKC1 mRNA and protein expressions were independent risk factors for BCSS (p < 0.01).

Conclusion: DKC1 expression is strongly correlated with NP and its overexpression in BC is associated with unfavourable clinicopathological characteristics and poor outcome. This has been a detailed example in the correlation of phenotype with genotype.
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http://dx.doi.org/10.1038/s41416-020-01045-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7653035PMC
November 2020

Identification and Functional Analysis of Temperate Siphoviridae Bacteriophages of .

Viruses 2020 05 31;12(6). Epub 2020 May 31.

Department of Bacteriology and Immunology, Medicum, Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland.

is an opportunistic pathogen that presents a serious clinical challenge due to its increasing resistance to all available antibiotics. Phage therapy has been introduced recently to treat antibiotic-incurable infections. In search for new specific bacteriophages, 20 clinical strains were used in two pools in an attempt to enrich phages from sewage. The enrichment resulted in induction of resident prophage(s) and three temperate bacteriophages, named vB_AbaS_fEg-Aba01, vB_AbaS_fLi-Aba02 and vB_AbaS_fLi-Aba03, all able to infect only one strain (#6597) of the 20 clinical strains, were isolated. Morphological characteristics obtained by transmission electron microscopy together with the genomic information revealed that the phages belong to the family . The ca. 35 kb genomic sequences of the phages were >99% identical to each other. The linear ds DNA genomes of the phages contained 10 nt cohesive end termini, 52-54 predicted genes, an site and one tRNA gene each. A database search revealed an >99% identical prophage in the genome of strain AbPK1 (acc. no. CP024576.1). Over 99% identical prophages were also identified from two of the original 20 clinical strains (#5707 and #5920) and both were shown to be spontaneously inducible, thus very likely being the origins of the isolated phages. The phage vB_AbaS_fEg-Aba01 was also able to lysogenize the susceptible strain #6597 demonstrating that it was fully functional. The phages showed a very narrow host range infecting only two strains. In conclusion, we have isolated and characterized three novel temperate phages that infect .
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http://dx.doi.org/10.3390/v12060604DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7354433PMC
May 2020

Heterologous expression, purification, immobilization and characterization of recombinant α-amylase AmyLa from Laceyella sp. DS3.

Int J Biol Macromol 2019 Jul 3;132:1274-1281. Epub 2019 Apr 3.

Botany and Microbiology Department, Faculty of Science, Damietta University, Egypt. Electronic address:

AmyLa α-amylase gene from Laceyella sp. DS3 was heterologously expressed in E. coli BL21. E. coli BL21 maximally expressed AmyLa after 4 h of adding 0.02 mM IPTG at 37 °C. The recombinant AmyLa α-amylase was purified 2.19-fold through gel filtration and ion exchange chromatography. We immobilized the purified recombinant AmyLa α-amylase on four carriers; chitosan had the best efficiency. The recombinant free and the immobilized AmyLa α-amylase showed optimum activity in the pH ranges of 6.0-7.0 and 4.0-7.0, respectively and possessed an optimum temperature of 55 °C. The free enzyme had activation energy, Km, and Vmax of 291.5 kJ, 1.5 mg/ml, and 6.06 mg/min, respectively. The immobilized enzyme had activation energy, Km, and Vmax of 309.74 kJ, 6.67 mg/ml, and 50 mg/min, respectively. The immobilized enzyme was calcium-independent and insensitive (relative to the free enzyme) to metals. It could also be reused for seven cycles.
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http://dx.doi.org/10.1016/j.ijbiomac.2019.04.010DOI Listing
July 2019

Allyl rhodanine azo dye derivatives: Potential antimicrobials target d-alanyl carrier protein ligase and nucleoside diphosphate kinase.

J Cell Biochem 2018 Sep 6. Epub 2018 Sep 6.

Chemistry Department, Faculty of Science, Damietta University, Damietta, Egypt.

3-Allyl-5-(4-arylazo)-2-thioxothiazolidine-4-one (HL ) ligands (where n = 1 to 3) were hypothesized to have antimicrobial activities mediated through inhibition of new antimicrobial targets. The ligands (HL ) were synthesized and characterized by infrared (IR) and H nuclear magnetic resonance ( H NMR) spectra. The ligands (HL ) were in silico screened to their potential inhibition to models of d-alanyl carrier protein ligase (DltA) (from Bacillus cereus, PDB code 3FCE) and nucleoside diphosphate kinase (NDK) (from Staphylococcus aureus; PDB code 3Q8U). HL ligand has the best energy and mode of binding to both NDK and DltA, even though its binding to DltA was stronger than that to NDK. In antimicrobial activity of HL ligand, morphological and cytological changes in HL -treated bacteria agreed with the in silico results. The HL ligand showed significant antimicrobial activity against B. cereus, S. aureus, and Fusarium oxysporium. The HL -treated bacterial cells appeared malformed and incompletely separated. Its cell walls appeared electron-lucent and ruptured. They contained more mesosomes than normal cells. It was found that the HL ligand represented as a bactericide against B. cereus and S. aureusby blocking target DltA, and may target NDK.
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http://dx.doi.org/10.1002/jcb.27473DOI Listing
September 2018

Occurrence of cyanobacteria and microcystin toxins in raw and treated waters of the Nile River, Egypt: implication for water treatment and human health.

Environ Sci Pollut Res Int 2015 Aug 10;22(15):11716-27. Epub 2015 Apr 10.

Botany Department, Faculty of Science, Sohag University, Sohag, 82524, Egypt,

Monitoring of cyanobacteria and their associated toxins has intensified in raw water sources of drinking water treatment plants (WTPs) in most countries of the world. However, it is not explored yet for Egyptian WTPs. Therefore, this study was undertaken to investigate the occurrence of cyanobacteria and their microcystin (MC) toxins in the Nile River source water of Damietta WTP during warm months (April-September 2013) and to evaluate the removal efficiency of both cyanobacterial cells and MCs by conventional methods used in this plant as a representative of Egyptian drinking WTPs. The results showed that the source water at the intake of Damietta WTP contained dense cyanobacterial population (1.1-6.6 × 107 cells L(-1)) dominated by Microcystis aeruginosa. This bloom was found to produce MC-RR and MC-LR. Both cyanobacterial cell density and intracellular MCs in the intake source water increased with the increase in temperature and nutrients during the study period, with maximum values obtained in August. During treatment processes, cyanobacterial cells were incompletely removed by coagulation/flocculation/sedimentation (C/F/S; 91-96.8%) or sand filtration (93.3-98.9%). Coagulation/flocculation induced the release of MCs into the ambient water, and the toxins were not completely removed or degraded during further treatment stages (filtration and chlorination). MCs in outflow tank water were detected in high concentrations (1.1-3.6 μg L - 1), exceeding WHO provisional guideline value of 1 μg L - 1 for MC-LR in drinking water. Based on this study, regular monitoring of cyanobacteria and their cyanotoxins in the intake source water and at different stages at all WTPs is necessary to provide safe drinking water to consumers or to prevent exposure of consumers to hazardous cyanobacterial metabolites.
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http://dx.doi.org/10.1007/s11356-015-4420-zDOI Listing
August 2015

Purification, sequencing, and biochemical characterization of a novel calcium-independent α-amylase AmyTVE from Thermoactinomyces vulgaris.

Appl Biochem Biotechnol 2013 Jun 4;170(3):483-97. Epub 2013 Apr 4.

Botany Department, Faculty of Science, Damietta University, P.O. Box 34517, New Damietta, Egypt.

α-Amylase from Thermoactinomyces vulgaris was highly purified 48.9-fold by ammonium sulfate precipitation, gel filtration on Sephadex G-50 column, and ion exchange chromatography column of DEAE-cellulose. The molecular weight of the enzyme was estimated to be 135 and 145 kDa by SDS-PAGE. Its high molecular weight is due to high glycosylation. The purified amylase exhibited maximal activity at pH 6.0 to 7.0 and was stable in the range of pH 4.0 to 9.0. The optimum temperature for its activity was 50 °C. The enzyme half-life time was 120 min at 50 °C, suggesting intermediate temperature stable α-amylase. The enzyme was sensitive to different metal ions, including NaCl, CoCl(2), and CaCl(2), and to different concentrations of EDTA. The enzyme activity was inhibited in the presence of 1 mM CaCl(2), suggesting that it is a calcium-independent α-amylase. The TLC showed that the amylase hydrolyzed starch to produce large maltooligosaccharides as the main products. A 1.1-kb DNA fragment of the putative α-amylase gene (amy TVE) from T. vulgaris was amplified by using two specific newly designed primers. Sequencing analysis showed 56.2 % similarity to other Thermoactinomyces α-amylases with two conserved active sites confirming its function.
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http://dx.doi.org/10.1007/s12010-013-0201-7DOI Listing
June 2013

Immunochemical identification and partial characterization of a native hepatitis C viral non-structural 4 antigen in sera of HCV infected patients.

Clin Chim Acta 2008 Feb 26;388(1-2):115-22. Epub 2007 Oct 26.

Research & Development Department, Biotechnology Research Center, New Damietta, Egypt.

Background: The identification of native HCV antigens may prove very useful in the diagnosis and early treatment of HCV infection. Here, we aimed to identify and partially characterize a native HCV-NS4 antigen.

Methods: The western blot, ELISA and immunohistochemical staining were used to identify the native antigen in sera and liver biopsies of HCV serotype 4 infected patients.

Results: The native NS4 antigen was identified in serum at 27-kDa molecular weight, in addition to a lower approximately 21-kDa antigen. The purified HCV antigen showed a polypeptide band at 27-kDa when analyzed by silver stained SDS-PAGE and a single peak at 7.6 min by capillary zone electrophoresis. The immunostaining pattern of hepatocytes was cytoplasmic with mainly coarse granular and diffuse pattern based on specific rabbit antisera to the native HCV antigen. A highly significant correlation (r=0.797, p<0.0001) was shown between serum concentrations of the HCV-NS4 antigen and HCV-RNA. Also, antigen detection rates were increased (p<0.05) with the progression of liver disease.

Conclusion: A native HCV-NS4 antigen was identified and partially characterized as 27-kDa protein and the NS4 antigenemia based ELISA test can serve as a useful addition to HCV diagnostic methods, especially under field condition.
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http://dx.doi.org/10.1016/j.cca.2007.10.019DOI Listing
February 2008

Production and immobilization of alpha-amylase from Bacillus subtilis.

Pak J Biol Sci 2007 Jun;10(12):2039-47

Department of Microbiology, Faculty of Pharmacy, Tanta University, Egypt.

Alpha-amylase production by Bacillus subtilis was studied under different cultivation conditions. The maximum alpha-amylase production occurred after an incubation period of 48 h, temperature 40 degrees C and pH 7.5. Among the defined carbohydrates, starch (1%) was the best carbon source. The organism grew better and produced high levels of alpha-amylase using peptone as nitrogen source. The produced alpha-amylase was immobilized on various carriers by different methods and the properties of the enzyme were compared before and after immobilization. The optimum pH of the immobilized enzyme was changed to acidic range. The optimum reaction temperature of immobilized enzyme was shifted slightly to 70-80 degrees C. Both of Km values and Vmax and thermal stability of immobilized enzyme were found to be higher than that of free one. Among the tested metals CaCl2 exerted a stimulating effect on the activity of alpha-amylase.
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http://dx.doi.org/10.3923/pjbs.2007.2039.2047DOI Listing
June 2007
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