Youssri Ahmed

Prof. Youssri Ahmed


Research Focus & Metrics

Academic Career Length

29Years (1998-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 July 2016 in Food Hydrocolloids
Verified
Journal Article
Closed access
ZZZipei Zhang
Zipei Zhang
RZRuojie Zhang
Ruojie Zhang
LZLiqiang Zou
Liqiang Zou
LCLong Chen
Long Chen
YAYoussri Ahmed
Youssri Ahmed
David Julian McClementsDavid Julian McClements
David Julian McClements

12 January 2018 in Scientific Reports
Verified
Journal Article
Open access
PDF file
TKTariq Jamal Khan
Tariq Jamal Khan
YAYoussri Ahmed
Youssri Ahmed
MZMazin A. Zamzami
Mazin A. Zamzami
SMSaleh A. Mohamed
Saleh A. Mohamed
IKImran Khan
Imran Khan
MYMuhammad Yasir
Muhammad Yasir
The aim of the present study was to investigate alterations in gut microbiota associated with hypercholesterolemia and treatment with atorvastatin, a commonly prescribed cholesterol-lowering drug. In this study, seven experimental groups of rats were developed based on diets [high-fat diet (HFD) and normal chow diet (NCD)] and various doses of atorvastatin in HFD and NCD groups. 16S rRNA amplicon sequencing was used to analyze the gut microbiota. Atorvastatin significantly reduced the cholesterol level in treated rats. Bacterial diversity was decreased in the drug-treated NCD group compared to the NCD control, but atorvastatin-treated HFD groups showed a relative increase in biodiversity compared to HFD control group. Atorvastatin promoted the relative abundance of Proteobacteria and reduced the abundance of Firmicutes in drug-treated HFD groups. Among the dominant taxa in the drug-treated HFD groups, Oscillospira, Parabacteroides, Ruminococcus, unclassified CF231, YRC22 (Paraprevotellaceae), and SMB53 (Clostridiaceae) showed reversion in population distribution toward NCD group relative to HFD group. Drug-treated HFD and NCD groups both showed an increased relative abundance of Helicobacter. Overall, bacterial community composition was altered, and diversity of gut microbiota increased with atorvastatin treatment in HFD group. Reversion in relative abundance of specific dominant taxa was observed with drug treatment to HFD rats.

1 February 2018 in OMICS: A Journal of Integrative Biology
Verified
Journal Article
Closed access
TKTariq Jamal Khan
Tariq Jamal Khan
YAYoussri Ahmed
Youssri Ahmed
MZMazin A. Zamzami
Mazin A. Zamzami
ASAisha M. Siddiqui
Aisha M. Siddiqui
IKImran Khan
Imran Khan
MYMuhammad Yasir
Muhammad Yasir
Hypercholesterolemia is one of the most important risk factors for development of cardiovascular diseases. The composition of gut microbiota (total microbes residing in the gut) impacts on cholesterol and lipid metabolism. On the contrary, alterations in gut microbiota in response to hypercholesterolemia or drug treatment with atorvastatin (a cholesterol-lowering agent) are rarely investigated. We performed 16S rDNA amplicon sequencing to evaluate the gut bacterial community of 15 untreated hypercholesterolemic patients (HP) and 27 atorvastatin-treated hypercholesterolemic patients (At-HP) and compared with 19 healthy subjects (HS). In total, 18 different phyla were identified in the study groups. An increase in relative abundance of Proteobacteria was observed in the HP group compared with At-HP and HS groups. The atherosclerosis-associated genus Collinsella was found at relatively higher abundance in the HP group. The anti-inflammation-associated bacteria (Faecalibacterium prausnitzii, Akkermansia muciniphila, and genus Oscillospira) were found in greater abundance, and proinflammatory species Desulfovibrio sp. was observed at decreased abundance in the drug-treated HP group compared with the untreated HP group. Relative abundances of the Bilophila wadsworthia and Bifidobacterium bifidum (bile acid-associated species) were decreased in the At-HP group. The At-HP and HS clustered separately from HP in the principal coordinate analysis. Decreased bacterial diversity was observed in the atorvastatin-treated group. In conclusion, these data suggest that atorvastatin treatment of patients with hypercholesterolemia may selectively restore the relative abundance of several dominant and functionally important taxa that were disrupted in the HP. Further studies are required to investigate the putative modifying effects of hypocholesterolemic drugs on functionality of gut microbiota, and the potential downstream effects on human health.


16 March 2016 in Biotechnology & Biotechnological Equipment
Verified
Journal Article
Open access
Ryan A. SheikhRyan A. Sheikh
Ryan A. Sheikh
OAOmar A. Al-Bar
Omar A. Al-Bar
YAYoussri Ahmed
Youssri Ahmed
Saccharomyces cerevisiae is an interesting micro-organism with good prospects in the future of yeast bioethanol production. In this study, both commercial and genetically modified S. cerevisiae were obtained from the local shops in Jeddah – Saudi Arabia and the Microbial Biotechnology Department – National Research Center (Dokki – Egypt) respectively, and incubated at 25 °C before being acclimatized for the conditions of this research. In this work, the impact of two different biochemical conditions (fermentation periods and nitrogen source concentration) on the growth, carbohydrates yields, and mainly bioethanol productivity from potato peels wastes (PPW) were studied in both species. PPW were used as a solo carbon source in this study with HCl acidic pre-treatment method. When studying the impact of fermentation periods, the best fermentation periods were found to be between the third and the fourth day. Additionally, the optimal nitrogen source concentration added to the fermentation medium was 2 g/L. This study concludes with some suggestions for future work in an attempt to reach commercial production of bioethanol at the lowest possible costs.

20 July 2016 in BMC Genomics
Verified
Journal Article
Open access
JSJerry W. Shay
Jerry W. Shay
NHNoriko Homma
Noriko Homma
RZRuyun Zhou
Ruyun Zhou
MNMuhammad Imran Naseer
Muhammad Imran Naseer
ACAdeel Chaudhary
Adeel Chaudhary
SBSaleh Binsaleh
Saleh Binsaleh
O1 Regulation of genes by telomere length over long distances