Papers by Othman ALGHAMDI
The Annals of the University Dunarea de Jos of Galati. Fascicle VI - Food Technology
The chemical composition and functional properties of olive (Olea europaea L.) leaf powder (OL) a... more The chemical composition and functional properties of olive (Olea europaea L.) leaf powder (OL) as an ingredient to be used in green and sustainable food processing were determined. OL contained low moisture (8% of dry weight) and fat (1.6%), moderate rates of proteins (10.8%) and high amounts of carbohydrates (70.8 %) composed mainly of insoluble fibers (57.9%). Due to its high content in insoluble fibers, OL displayed high fat absorption power and moderate water solubility index and holding capacity. Therefore, OL can be an appropriate ingredient to stabilize lipid rich food formulations. OL was incorporated at an industrial scale in a pistachio paste based confectionery product. This addition enabled to protect the oil from oxidation during cooking, drying and storage of the pistachio paste mixture. Moreover, the microbiological quality, textural properties, sensory attributes, and overall acceptance of the product were improved. This work promotes the use of OL as a health promo...
Amino Acids
Hypertension is a major risk factor for kidney and cardiovascular disease. The treatment of hyper... more Hypertension is a major risk factor for kidney and cardiovascular disease. The treatment of hypertensive individuals by selected ACE inhibitors and certain di-and tripeptides halts the progression of renal deterioration and extends life-span. Renal reabsorption of these low molecular weight substrates are mediated by the PEPT1 and PEPT2 cotransporters. This study aims to investigate whether hypertension and ageing affects renal PEPT cotransporters at gene, protein expression and distribution as well as function in the superficial cortex and the outer medulla of the kidney. Membrane vesicles from the brush border (BBMV) and outer medulla (OMMV) were isolated from the kidneys of young Wistar Kyoto (Y-WKY), young spontaneously hypertensive (Y-SHR), and middle aged SHR (M-SHR) rats. Transport activity was measured using the substrate, β-Ala-Lys (AMCA). Gene expression levels of PEPT genes were assessed with qRT-PCR while renal localisation of PEPT cotransporters was examined by immunohistochemistry with Western Blot validation. The Km and Vmax of renal PEPT1 were decreased significantly in SHR compared to WKY BBMV, whilst the Vmax of PEPT2 showed differences between SHR and WKY. By contrast to the reported cortical distribution of PEPT1, PEPT1-staining was detected in the outer medulla, whilst PEPT2 was expressed primarily in the cortex of all SHR; PEPT1 was significantly upregulated in the cortex of Y-SHR. These outcomes are indicative of a redistribution of PEPT1 and PEPT2 in the kidney proximal tubule under hypertensive conditions that has potential repercussions for nutrient handling and the therapeutic use of ACE inhibitors in hypertensive individuals.
Probiotics and Antimicrobial Proteins, 2022
Antibiotic growth promoters have been utilized for long time at subtherapeutic levels as feed sup... more Antibiotic growth promoters have been utilized for long time at subtherapeutic levels as feed supplements in monogastric animal rations. Because of their side-effects such as antibiotic resistance, reduction of beneficial bacteria in the gut, and dysbiosis, it is necessary to look for non-therapeutic alternatives. Probiotics play an important role as the key substitutes to antibacterial agents due to their many beneficial effects on the monogastric animal host. For instance, enhancement of the gut microbiota balance can contribute to improvement of feed utilization efficiency, nutrients absorption, growth rate, and economic profitability of livestock. Probiotics are defined as "live microorganisms that, when administered in adequate amounts, confer a health benefit on the host." They are available in diverse forms for use as feed supplements. Their utilization as feed additives assists in good digestion of feed ingredients and hence, making the nutrients available for promoting growth. Immunity can also be enhanced by supplementing probiotics to monogastrics diets. Moreover, probiotics can help in improving major meat quality traits and countering a variety of monogastric animals infectious diseases. A proper selection of the probiotic strains is required in order to confer optimal beneficial effects. The present review focuses on the general functional, safety, and technological screening criteria for selection of ideal Bacillus probiotics as feed supplements as well as their mechanism of action and beneficial effects on monogastric animals for improving production performance and health status.
International Journal of Peptide Research and Therapeutics, 2021
The present study investigates the nephroprotective and the molecular mechanisms effects of Liza ... more The present study investigates the nephroprotective and the molecular mechanisms effects of Liza aurata protein hydrolysates (LAPHs) against paracetamol induced nephrotoxicity and oxidative stress in rats. Oxidative stress as evident by increased malondialdehyde, hydrogen peroxide, advanced oxidation protein product, protein carbonyl, with significant decrease in non protein thiol and glutathione contents, as well as catalase, superoxide dismutase, and glutathione reductase activities. Paracetamol triggered inflammatory response by inducing tumor necrosis factor-α (TNF-α), with the increased expression of cyclooxygenase-2 (Cox-2). Paracetamol also increased alkaline phosphatase (ALP) and lactate deshydrogenase (LDH) activities, along with an increase in blood urea nitrogen, creatinine, low density lipoprotein cholesterol, and total bilirubin levels. LAPHs were found to decrease leakage of LDH and ALP activity and attenuate the increase in biochemical parameters resulted in a subsequ...
Essentials of Bioinformatics, Volume II, 2019
Regulation of gene expression is a complex process which require several players working together... more Regulation of gene expression is a complex process which require several players working together in different time and space in a cell or tissue level. In eukaryotes, gene expression regulation is maintained by a complicated dynamic interplay between proximal promoters and distal regulatory elements (REs) such as repressors and enhancers and transcription factors (TFs). TFs are an important regulator of various life processes and diseases. Ample evidence now suggests that the regulatory networks and the interactions between target binding sites and various TFs play pivotal role in several diseases including cancers. TFs also play a key role in differential gene expression which has proven important in understanding the biological differences between healthy and diseased states. In this book chapter, we discuss about a genomic tool named DiRE which can predict distant REs based on transcription factor binding sites (TFBSs). It possesses a unique capacity to detect REs beyond regions of proximal promoter. DiRE can predict common REs in the coregulated genes. Here we describe step by step method to use this tool. At last, we also discuss the advantages and possible limitation of this tool use for genomic applications.
Journal of Molecular Structure, 2021
Abstract The present study describes the synthesis and biological investigation of novel ethyl 4,... more Abstract The present study describes the synthesis and biological investigation of novel ethyl 4,4,4-trifluoro-3-hydrazonobutanoate derivatives, which were synthesized by condensation of commercially available hydrazines and ethyl 4,4,4-trifluorobut-2-ynoate. We explored the chemical space of these new fluorinated compounds to determine their antioxidant and antibacterial activities and their angiotensin I-converting enzyme (ACE) inhibition ability. The results indicated that the seven compounds synthesized revealed excellent antioxidant activity with inhibition values in the range of 67.83 ± 0.001-95.77 ± 0.05% at 2 µM. The compound 3g displayed the highest ACE inhibitory activity with an IC50 of 2.42 µM. The results revealed also that compound 3e was highly active against S. typhi, L. monocytogenes and K. pneumoniae. The docking of chemical compounds in the ACE active site showed possible inhibitory effect of all compounds on the catalytic activity of the enzyme, which would satisfactorily explain the anti-hypertensive effect of these compounds.
Biotechnology Progress, 2020
The Bacillus subtilis US191 strain producing highly thermostable β-mannanase was previously selec... more The Bacillus subtilis US191 strain producing highly thermostable β-mannanase was previously selected as potential probiotic candidate for application as feed supplement in poultry industry. Initially, the level of extracellular β-mannanase production by this strain was 1.48 U mL-1 . To improve this enzyme titer, the present study was undertaken to optimize the fermentation conditions through experimental designs and valorization of agro-industrial byproducts. Using the Plackett-Burman design, in submerged fermentation, a set of 14 culture variables was evaluated in terms of their effects on β-mannanase production. Locust bean gum "LBG", soymeal, temperature and inoculum size were subsequently optimized by response surface methodology using Box-Behnken design. Under optimized conditions (1g L-1 LBG, 8 g L-1 soymeal, temperature of 30 °C and inoculum size of 1010 CFU mL-1 ), a 2.59-fold enhancement in β-mannanase titer was achieved. Next, to decrease the enzyme production cost, the effect of partial substitution of LBG (1 g L-1 ) by agro-industrial byproducts was investigated, and a Taguchi design was applied. This allowed the attaining of a β-mannanase production level of 8.75 U mL-1 in presence of 0.25 g L-1 LBG, 5 g L-1 of coffee residue powder, 5 g L-1 of date seeds powder and 5 g L-1 of prickly pear seeds powder as mannans sources. Overall, a 5.91-fold improvement in β-mannanase production by B. subtilis US191 was achieved. This article is protected by copyright. All rights reserved.
Molecular and cellular biochemistry, Jan 17, 2018
Renal PEPT1 and PEPT2 cotransporters play an important role in the balance of circulating body ol... more Renal PEPT1 and PEPT2 cotransporters play an important role in the balance of circulating body oligopeptides and selected peptidomimetic drugs. We aim to comprehensively characterise age-related changes of the renal PEPT cotransporters at the gene, protein, and functional level. Brush border membrane vesicles (BBMV) and outer medulla membrane vesicles (OMMV) were isolated from the kidneys of young, middle-aged and old rats. The protein expression of PEPT1 was not only increased in BBMV from old rats, but PEPT1 also appeared in OMMV from middle-aged and old rats. SLC15A1 gene expression in the renal cortex increased in middle-aged group. PEPT2 protein expression was not only increased with ageing, but PEPT2 also was found in BBMV from middle-aged and old groups. SLC15A2 gene expression in the renal outer medulla increased in the old group. These changes in the expressions and localisations of PEPT1 and PEPT2 could explain the changes to transport activity in BBMV and OMMV. These find...
Biochimica et biophysica acta, Jan 29, 2017
Integral membrane proteins PEPT1 and PEPT2 are essential for reabsorbing almost all hydrolysed or... more Integral membrane proteins PEPT1 and PEPT2 are essential for reabsorbing almost all hydrolysed or filtered di- and tripeptides alongside a wide range of peptidomimetic drugs in the kidney. The aim of this study was to investigate the potential use of the fluorophore-conjugated dipeptide β-Ala-Lys (AMCA) as a biosensor for measuring peptide transport activity in brush border membrane vesicles isolated from the outer cortex (BBMV-OC) and outer medulla (BBMV-OM) (representing PEPT1 and PEPT2 respectively). The vesicles were isolated using a dual magnesium precipitation and centrifugation technique. Intravesicular fluorescence accumulation was measured after incubating extra-vesicular media at pH6.6 and different concentrations of β-Ala-Lys (AMCA) with vesicles pre-equilibrated at pH7.4. Both BBMV-OC and BMMV-OM showed accumulation of an intravesicular fluorescence signal after 20min incubation. Changing the extra-vesicular pH to 7.4 caused a significant reduction in the β-Ala-Lys (AMCA...
International Journal of Bioscience, Biochemistry and Bioinformatics, 2012
The generation and maintenance of the membrane potential difference is of fundamental importance ... more The generation and maintenance of the membrane potential difference is of fundamental importance to the livelihood of every cell. The aim of this study was to show for the first time that the fluorescent indicator, 3'3-dipropylthiacarbocyanine iodide (DiS-C 3-(3)) could be used as a reporter of the membrane potential difference in various membrane vesicle populations isolated from the rat kidney. When thesemembrane vesicles were added to a solution that imposed different transmembrane potassium gradients the measured change in fluorescence (F) was dependent upon the predicted membrane potential difference. The more positive the membrane potential difference, the smaller the F measured. To illustrate the potential applicability of this dye for measuring membrane transport phenomena it was shown that DiSC 3-(3)fluorescence was sensitive to the more subtle changes in membrane potential evoked by the electrogenic transport activities associated with the H +-coupled uptake of L-glycyl-L-glutamine into brush border membrane vesicles isolated from the rat kidney. These findings demonstrate the suitability of DiSC 3-(3) as a biosensor of the membrane potential difference with scope for a broad range of applications.
Amino Acids, 2021
Some dipeptides have been implicated in myocardial protection, but little is known about their me... more Some dipeptides have been implicated in myocardial protection, but little is known about their membrane transporter PEPT2. The aim of this study was to determine whether the expression and activity of the cardiac-type PEPT2 cotransporter could be affected by ageing and/or hypertension. Sarcolemmal vesicles (SV) were isolated from the hearts of all rat groups using a standard procedure to investigate the transport activity and protein abundance by fluorescence spectroscopy and Western blot, respectively. SLC15A2 “PEPT2” gene expression was relatively quantified by RT-qPCR. In the Wistar rat groups, the protein and gene expression of PEPT2 were upregulated with ageing. These changes were accompanied by corresponding increases in the competitive inhibition and the transport rate ( V max ) of β-Ala-Lys (AMCA) into SV isolated from middle-aged hearts. Although, the transport rate of β-Ala-Lys (AMCA) into SV isolated from old hearts was significantly the lowest compared to middle-aged and young adult hearts, the inhibition percentage of β-Ala-Lys (AMCA) transport by Gly-Gln was the highest. In the WKY and SHR rat groups, Y-SHR hypertrophied hearts showed an increase in PEPT2 gene expression accompanied by a significant decrease in protein expression and activity. With advanced age, however, M-SHR hypertrophied hearts revealed significantly lower gene expression, but higher protein expression and activity than Y-SHR hearts. These findings suggest that increased expression of PEPT2 cotransporter in all types of middle-aged hearts could be exploited to facilitate di-and tripeptide transport by PEPT2 in these hearts, which subsequently could result in improved myocardial protection in these populations.
Amino acids, Jan 7, 2015
The amino acids glycine and glutamine have been implicated in myocardial protection of the much s... more The amino acids glycine and glutamine have been implicated in myocardial protection of the much studied young adult heart. This study aimed to determine whether such protection could be enhanced using the dipeptide, L-glycyl-L-glutamine (gly-gln) in both young hearts and in middle-aged hearts representative of a more clinically relevant age group. Hearts from 8-week-old and 36-week-old rats were perfused in the Langendorff mode for 20 min, before 40 min global normothermic ischaemia and 30 min reperfusion. Where present, 0.5, 2, or 5 mM gly-gln was added 10 min into baseline perfusion, was present throughout ischaemia and was washed out after 10 min reperfusion. Reperfusion damage was assessed from the release of lactate dehydrogenase. Metabolic fitness was assessed from the time to ischaemic contracture and the accumulation of lactate and thiobarbituric acid reactive substances during ischaemia. The presence of 5 mM gly-gln significantly improved the post-ischaemic rate pressure pr...
ABSTRACT PEPT1 and PEPT2 are H+-dependent cotransporters found in the kidney. They are important ... more ABSTRACT PEPT1 and PEPT2 are H+-dependent cotransporters found in the kidney. They are important for the reabsorption of small peptides and are also capable of transporting a broad range of peptidomimetic drugs. Due to the electrogenic nature of these carriers, transport of individual substrates should be accompanied by a positive change in the membrane potential difference (pd). The aim of this study was to investigate a novel use for the potential sensitive fluorescent dye 3,30-dipropylthiacarbocyanine iodide [DiS-C₃-(3)] as a biosensor for dipeptide transport across the renal proximal tubule apical membrane. Brush border (BBMV) and outer medulla (OMMV) membrane vesicles were isolated from male Wistar rats using standard techniques. Fluorescence changes were measured when extracellular media at pH 6.6 containing 0-3 mM L-glycyl-L-glutamine (gly-gln) was added to a cuvette containing vesicles pre-equilibrated at pH 7.4 and 7.5 μM DiS-C₃-(3). Data presented are means ± SE of n = 6. A positive change in fluorescence occurred upon gly-gln addition reflecting the expected positive change in membrane pd.
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Papers by Othman ALGHAMDI