Mohamed, M. S. M., A. A. Asair, N. A. H. Fetyan, and S. M. Elnagdy, "Complete Biodegradation of Diclofenac by New Bacterial Strains: Postulated Pathways and Degrading Enzymes", Microorganisms, vol. 11, no. 6, 2023. AbstractWebsite

The accumulation of xenobiotic compounds in different environments interrupts the natural ecosystem and induces high toxicity in non-target organisms. Diclofenac is one of the commonly used pharmaceutical drugs that persist in the environment due to its low natural degradation rate and high toxicity. Therefore, this study aimed to isolate potential diclofenac-degrading bacteria, detect the intermediate metabolites formed, and determine the enzyme involved in the degradation process. Four bacterial isolates were selected based on their ability to utilize a high concentration of diclofenac (40 mg/L) as the sole carbon source. The growth conditions for diclofenac degradation were optimized, and bacteria were identified as Pseudomonas aeruginosa (S1), Alcaligenes aquatilis (S2), Achromobacter spanius (S11), and Achromobacter piechaudii (S18). The highest percentage of degradation was recorded (97.79 ± 0.84) after six days of incubation for A. spanius S11, as analyzed by HPLC. To detect and identify biodegradation metabolites, the GC-MS technique was conducted for the most efficient bacterial strains. In all tested isolates, the initial hydroxylation of diclofenac was detected. The cleavage step of the NH bridge between the aromatic rings and the subsequent cleavage of the ring adjacent to or in between the two hydroxyl groups of polyhydroxylated derivatives might be a key step that enables the complete biodegradation of diclofenac by A. piechaudii S18, as well as P. aeruginosa S1. Additionally, the laccase, peroxidase, and dioxygenase enzyme activities of the two Achromobacter strains, as well as P. aeruginosa S1, were tested in the presence and absence of diclofenac. The obtained results from this work are expected to be a useful reference for the development of effective detoxification bioprocesses utilizing bacterial cells as biocatalysts. The complete removal of pharmaceuticals from polluted water will stimulate water reuse, meeting the growing worldwide demand for clean and safe freshwater.

Elshaghabee, F. M. F., A. El-Hussein, and M. S. M. Mohamed, "Enhancement of Labneh Quality by Laser-Induced Modulation of Lactocaseibacillus casei NRRL B-1922", Fermentation, vol. 8, no. 3, 2022. AbstractWebsite

Labneh is positioned in the top ranking of the bestselling dairy products all over the world due to its health benefits and delicious taste. Labneh production depends mainly on probiotic bacteria in the fermentation of milk. Probiotic bacteria have many health benefits, which are driven by their selective bioactive metabolites that quantitively affect the fermentation products. The current investigation aimed to study the implementation of photobiomodulation through the irradiation of Lacticaseibacillus casei NRRL-B-1922 by a He–Ne laser (630 nm) with different laser doses (3, 6 & 12 J/cm2) prior to milk fermentation. This procedure sought to improve the probiotic bacteria’s activities while enhancing the labneh’s characteristics and consequently produce a more favorable labneh product with better marketing qualities. The photobiostimulated bacterial starter was found to induce increased titratable acidity with the moisture reduction of the labneh product under cold storage conditions for 20 days. The effect was most prominent when using a 12 J/cm2 laser dose. The flavor-aiding components, mainly diacetyl and acetaldehyde compounds, and sensory scores were increased in the labneh produced by irradiated L. casei when compared to the non-radiated probiotic culture after storing the products under cold conditions for 20 consecutive days. Moreover, the antioxidant and proteolytic activities of labneh produced by treated L. casei (12 J/cm2 laser dose) after cold storage were significantly elevated by 41 and 14%, respectively. In conclusion, we can report significantly improved selected characteristics in the final products after the employment of photobiomodulation process, the potential application of this concept on the industrial scale, and its implications on lengthening the product shelf life with improved qualities.

Almuhayawi, M. S., M. S. M. Mohamed, M. Abdel-Mawgoud, S. Selim, S. K. Al Jaouni, and H. Abdelgawad, "Bioactive potential of several actinobacteria isolated from microbiologically barely explored desert habitat, Saudi Arabia", Biology, vol. 10, no. 3, 2021. AbstractWebsite

Biomolecules from natural sources, including microbes, have been the basis of treatment of human diseases since the ancient times. Therefore, this study aimed to investigate the potential bioactivity of several actinobacteria isolates form Al-Jouf Desert, Saudi Arabia. Twenty-one actinobac-terial isolates were tested for their antioxidant (flavonoids, phenolics, tocopherols and carotenoids) content, and biological activities, namely FRAP, DPPH, ABTS, SOS and XO inhibition, anti-hemolytic and anti-lipid peroxidation as well as their antibacterial and antiprotozoal activities. Accordingly, five isolates (i.e., Act 2, 12, 15, 19 and 21) were selected and their 90% ethanolic extracts were used. The phylogenetic analysis of the 16S rRNA sequences indicated that the most active isolates be-long to genus Streptomyces. The genus Streptomyces has been documented as a prolific producer of biologically active secondary metabolites against different cancer types. Thus, the anti-blood cancer activity and the possible molecular mechanisms by which several Streptomyces species extracts inhibited the growth of different leukemia cells, i.e., HL-60, K562 and THP-1, were investigated. In general, the five active isolates showed cytotoxic activity against the tested cell lines in a dose dependent manner. Among the potent isolates, isolate Act 12 significantly decreased the cell viability and showed maximum cytotoxic activities against both HL-60 and K562 cells, while isolate Act 15 exhibited maximum cytotoxic activity against THP-1 cells. Moreover, Act 2 and Act 12 reduced cyclooxygenase (COX-2) and lipoxygenase (LOX) activity, which is involved in the proliferation and differentiation of cancer cells and may represent a possible molecular mechanism underlying leukemia growth inhibition. The bioactive antioxidant extracts of the selected Streptomyces species inhibited leukemia cell growth by reducing the COX-2 and LOX activity. Overall, our study not only. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Moustafa, E., E. Abdelsalam, Y. A. Attia, M. S. M. Mohamed, M. Salah, M. A. Moselhy, A. S. Ali, and M. Samer, "Enhancing the performance of microbial fuel cells by installing an air pump to the cathode chamber", Egyptian Journal of Chemistry, vol. 64, no. 10, pp. 5471-5476, 2021. AbstractWebsite

The microbial fuel cells (MFCs) are biochemical devices in which bacteria create electrical power by oxidizing simple compounds such as glucose as well as complex organic matter in wastewater. In this study, pumping air into the cathode chamber and its effect on microbial fuel cell performance was investigated. The metabolism of bacteria existed in wastewater was responsible for the generation of bioelectricity. The developed MFC system was designed by utilizing phosphate buffer to operate the system at controlled pH equal 7 and at a stable temperature of 30°C. It was found that increasing oxygen supply to the cathode chamber has a positive effect on the cell performance by increasing the voltage value. Generally, the efficiency of microbial fuel cell was enhanced in the case of cathodic chamber aeration in comparison to the case of no aeration was applied. It was found that the voltage increased in the case of oxygen supply to reach 0.45 mv with a stability over the 138 h of the experiment compared to the case of no aeration was applied where the voltage reached only 0.2 mV with stability in one case and 0.4 mV after 78 h of operation with instability in the second case. Therefore, the performance of the microbial fuel cell improved. It can be concluded that oxygen concentration affects both reaction kinetics and final power efficiency. © 2021 National Information and Documentation Center (NIDOC).

Elshaghabee, F. M. F., A. A. A. El-Maksoud, S. A. Alharbi, S. Alfarraj, and M. S. M. Mohamed, "Fortification of acidophilus-bifidus-thermophilus (Abt) fermented milk with heat-treated industrial yeast enhances its selected properties", Molecules, vol. 26, no. 13, 2021. AbstractWebsite

The improvement of milk dairy products’ quality and nutritional value during shelf-life storage is the ultimate goal of many studies worldwide. Therefore, in the present study, prospective beneficial effects of adding two different industrial yeasts, Kluyveromyces lactis and Saccharomyces cerevisiae pretreated by heating at 85◦C for 10 min to be inactivated, before fermentation on some properties of ABT fermented milk were evaluated. The results of this study showed that the addition of 3% and 5% (w/v) heat-treated yeasts to the milk enhanced the growth of starter culture, Lactobacillus acidophilus, Bifidobacteria, and Streptococcus thermophilus, during the fermentation period as well as its viability after 20 days of cold storage at 5 ± 1◦C. Furthermore, levels of lactic and acetic acids were significantly increased from 120.45 ± 0.65 and 457.80 ± 0.70 µg/mL in the control without heat-treated yeast to 145.67 ± 0.77 and 488.32 ± 0.33 µg/mL with 5% supplementation of Sacch. cerevisiae respectively. Moreover, the addition of heat-treated yeasts to ABT fermented milk enhanced the antioxidant capacity by increasing the efficiency of free radical scavenging as well as the proteolytic activity. Taken together, these results suggest promising application of non-viable industrial yeasts as nutrients in the fermentation process of ABT milk to enhance the growth and viability of ABT starter cultures before and after a 20-day cold storage period by improving the fermented milk level of organic acids, antioxidant capacity, and proteolytic activities. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Mohamed SH, Elshahed MMS, Saied YM, Mohamed MSM, and O. GH., "Detection of Heavy Metal Tolerance among different MLSB Resistance Phenotypes of Methicillin-Resistant S. aureus (MRSA).", J Pure Appl Microbiol., vol. 14, issue (3), pp. 1905-1916, 2020. jpam_vol_14_issue3_p_1905-1916.pdf
Al Kashgry, N. A. T., H. H. Abulreesh, I. A. El-Sheikh, Y. A. Almaroai, R. Salem, I. Mohamed, F. R. Waly, G. Osman, and M. S. M. Mohamed, Utilization of a recombinant defensin from Maize (Zea mays L.) as a potential antimicrobial peptide, , vol. 10, issue 1, pp. 208, 2020. AbstractWebsite

The search for effective and bioactive antimicrobial molecules to  encounter the medical need for new antibiotics is an encouraging area of research. Plant defensins are small cationic, cysteine-rich peptides with a stabilized tertiary structure by disulfide-bridges and characterized by a wide range of biological functions. The heterologous expression of Egyptian maize defensin (MzDef) in Escherichia coli and subsequent purification by glutathione affinity chromatography yielded 2 mg/L of recombinant defensin peptide. The glutathione-S-transferase (GST)-tagged MzDef of approximately 30 kDa in size (26 KDa GST +  ~ 4 KDa MzDef peptide) was immunodetected with anti-GST antibodies. The GST-tag was successfully cleaved from the MzDef peptide by thrombin, and the removal was validated by the Tris-Tricine gel electrophoresis. The MzDef induced strong growth inhibition of Rhizoctonia solani, Fusarium verticillioides, and Aspergillus niger by 94.23%, 93.34%, and 86.25%, respectively, whereas relatively weak growth inhibitory activity of 35.42% against Fusarium solani was recorded. Moreover, strong antibacterial activities were demonstrated against E. coli and Bacillus cereus and the moderate activities against Salmonella enterica and Staphylococcus aureus at all tested concentrations (0.1, 0.2, 0.4, 0.8, 1.6, and 3.2 µM). Furthermore, the in vitro MTT assay exhibited promising anticancer activity against all tested cell lines (hepatocellular carcinoma, mammary gland breast cancer, and colorectal carcinoma colon cancer) with IC50 values ranging from 14.85 to 29.85 µg/mL. These results suggest that the recombinant peptide MzDef may serve as a potential alternative antimicrobial and anticancer agent to be used in medicinal application.

Yehia, R. S., G. H. Osman, H. Assaggaf, R. Salem, and M. S. M. Mohamed, "Isolation of potential antimicrobial metabolites from endophytic fungus Cladosporium cladosporioides from endemic plant Zygophyllum mandavillei", South African Journal of Botany, 2020. AbstractWebsite

This study aimed to test and evaluate antibacterial and antifungal activities of secondary metabolites obtained from endophytic fungi isolated from the leaves of endemic plant Zygophyllum mandavillei. The fungus Cladosporium cladosporioides was the predominant isolated fungus with colonization and dominance frequencies percentage of 12.50 and 39.32 respectively. C. cladosporioides extract was found to have the best antimicrobial activity causing a zone of inhibition ranging from 20.7 to 25.7 mm against all tested bacterial and fungal phytopathogens. Gas Chromatography/Mass Spectrometry (GC/MS) analysis of the extract successfully identified six major compounds: Cladosporin, Isocladosporin, 5′- hydroxyasperentin, Di (2-ethylhexyl) phthalate, 1-acetyl-17-methoxyaspidospermidin-20-ol, and 3-phenylpropionic acid. Enhanced antimicrobial activity was recorded for 3-phenylpropionic acid with MIC value ranging from 3.90 to 15.62 μg/ml followed by 5′- hydroxyasperentin with MIC ranging from 7.81 to 62.5 μg/ml. The most effective compound, 3-phenylpropionic acid, was further characterized by Fourier transform infrared spectroscopy (FT-IR) in addition to nuclear magnetic resonance (NMR) and mass spectroscopy to elucidate the chemical structure. The cytotoxicity of 3-phenylpropionic acid revealed a lower level of cytotoxicity at the concentration range 0.01–10 µg/ml as indicated by the cell viability percentage which is ranging from 75.47–94.14%. These results suggested that 3-phenylpropionic acid may serve as a potential alternative approach for the management of plant phytopathogens.

Abdelmohsen, G., G. T. M. Dawoud, and M. S. M. Mohamed, "Investigation of the biochemical and ultrastructural mechanisms underlying the antimicrobial activity of Mimusops spp. extracts", Baghdad Science Journal, vol. 17, no. 2, pp. 452-462, 2020. AbstractWebsite