Publications by authors named "Salman Alamery"

34 Publications

Potency of plant extracts against Penicillium species isolated from different seeds and fruits in Saudi Arabia.

Saudi J Biol Sci 2021 Jun 4;28(6):3294-3302. Epub 2021 Mar 4.

Department of Biochemistry, College of Science, King Saud University, PO Box 22452, Riyadh 11451, Saudi Arabia.

Antifungal activity of extracts of cinnamon (Cinnamomum zeylanicum), Cloves (Syzygium aromaticum), ginger (Zingiber officinale) and turmeric (Curcuma longa) were evaluated against 17 . Seed disease and rotten fruit caused by these species cause considerable loss of quality for different agricultural products. Isolates of spp. were screened for production of patulin an important serious mycotoxin. About 70.59% of spp. produced this toxin in concentrations ranging from 4 to 31 ppb. The response of spp. to plant extracts differed according to the plant extract and concentration. Cinnamon extract showed the greatest effect on , and cloves extract produced the greatest effect on . Turmeric extract had less effect on . Cloves extract was the most effective in reducing the growth of . On the other hand, ginger extract with all concentrations used had less effect against most spp in the laboratory. Plant extracts are promising as natural sources of environmentally friendly compounds in laboratory studies.
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http://dx.doi.org/10.1016/j.sjbs.2021.02.074DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8176084PMC
June 2021

Molecular mechanisms underlying antitumor activity of camel whey protein against multiple myeloma cells.

Saudi J Biol Sci 2021 Apr 28;28(4):2374-2380. Epub 2021 Jan 28.

Department of Biochemistry, College of Science, King Saud University, PO Box 22452, Riyadh 11451, Saudi Arabia.

Treating drug-resistant cancer cells is a clinical challenge and it is also vital to screen for new cancer drugs. Multiple myeloma (MM) is a plasma cell clonal cancer that, despite many experimental therapeutics, remains incurable. In this study, two MM cell line lines U266 and RPMI 8226 were used to determine the impact of camel whey protein (CWP). The CWP IC was calculated by MTT examination, while the flow cytometry analysis was used to investigate the chemotaxis responses of MM cells in relation to CXCL12 and the pro-apoptotic effect of CHP. MM cells were treated with CWP and Western blot analysis was used to determine the underlying molecular mechanisms. Dose and time based on the impact of CWP on the cell viability of MM cells with IC of 50 μg/ml, without affecting the viability of normal healthy PBMCs. CWP reduced chemotaxis of MM cells significantly from the CXC chemokine ligand 12 (CXCL12). Using Western blot analysis, we found that CWP decreased the activation of AKT, mTOR, PLCβ3, NFαB and ERK, which was mechanistically mediated by CXCL12/CXCR4. In both U266 and RPMI 8226, CWP induced apoptosis by upregulating cytochrome expression. In addition, CWP mediated the growth arrest of MM cells by robustly decreasing the expression of the anti-apoptotic Bcl-2 family members Bcl-2, Bcl-XL and Mcl-1. Conversely, the expression of pro-apoptotic Bcl-2 family members Bak, Bax and Bim was increased after treatment with CWP. Our data indicates CWP's therapeutic potential for MM cells.
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http://dx.doi.org/10.1016/j.sjbs.2021.01.034DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8071924PMC
April 2021

Corrigendum to "Structural and functional characterization of Tomato gene" [Saudi J. Biol. Sci. 27(1) (2020) 352-357].

Saudi J Biol Sci 2021 Feb 5;28(2):1502. Epub 2021 Feb 5.

Plant Production Department, Food Science and Agricultural College, King Saud University, PO Box 2455-11451, Riyadh, Saudi Arabia.

[This corrects the article DOI: 10.1016/j.sjbs.2019.10.004.].
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http://dx.doi.org/10.1016/j.sjbs.2021.01.055DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7878701PMC
February 2021

Induction of liver fibrosis by CCl4 mediates pathological alterations in the spleen and lymph nodes: The potential therapeutic role of propolis.

Saudi J Biol Sci 2021 Feb 26;28(2):1272-1282. Epub 2020 Nov 26.

Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia.

In an animal models, carbon tetrachloride (CCl) is a carcinogenic agent that causes liver fibrosis. The current study aims to investigate whether induction in liver-fibrosis by CCl in the mouse model could promote the initiation of fibrosis in lymph node and spleen due to sustained increase of inflammatory signals and also aimed to clarify the protective therapeutic effects of propolis. The male mice (BALB/c) were categorized into three experimental sets and each group involved 15 mice. Control group falls into first group; group-II and group-III were injected with CCl to induce liver-fibrosis and oral supplementation with propolis was provided in group-III for 4-weeks. A major improvement with hepatic collagen and α-smooth muscle actin (α-SMA) production was aligned with the activation of liver fibrosis from CCl. Mice treated with CCl exhibited collagen deposition towards liver sections, pathological alterations in spleen and lymph node architectures, and a significantly increase the circulation of both T&B cells in secondary lymphoid organs. Mechanically, the secondary lymphoid organs treated with CCl in mice exposed a positive growth in α-SMA and collagen expression, increased in proinflammatory cytokine levels and a significant increase in TGF-β, NO and ROS levels. A manifest intensification in the expression of Nrf2, COX-2, and eNOS and upregulation of ASK1 and P38 phosphorylation. Interestingly, addition of propolis-treated CCl mice, substantially suppressed deposition of liver collagen, repealed inflammatory signals and resorted CCl-mediated alterations in signaling cascades, thereby repairing the architectures of the secondary lymphoid organs. Our findings revealed benefits of propolis against fibrotic complications and enhancing secondary lymphoid organ architecture.
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http://dx.doi.org/10.1016/j.sjbs.2020.11.068DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7878719PMC
February 2021

Morphology, Structural, Thermal, and Tensile Properties of Bamboo Microcrystalline Cellulose/Poly(Lactic Acid)/Poly(Butylene Succinate) Composites.

Polymers (Basel) 2021 Feb 1;13(3). Epub 2021 Feb 1.

Department of Biochemistry, College of Science, King Saud University, P.O. Box 22452, Riyadh 11451, Saudi Arabia.

The present study aims to develop a biodegradable polymer blend that is environmentally friendly and has comparable tensile and thermal properties with synthetic plastics. In this work, microcrystalline cellulose (MCC) extracted from bamboo-chips-reinforced poly (lactic acid) (PLA) and poly (butylene succinate) (PBS) blend composites were fabricated by melt-mixing at 180 °C and then hot pressing at 180 °C. PBS and MCC (0.5, 1, 1.5 wt%) were added to improve the brittle nature of PLA. Field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscope (FTIR), thermogravimetric analysis (TGA), differential thermogravimetry (DTG), differential scanning calorimetry (DSC)), and universal testing machine were used to analyze morphology, crystallinity, physiochemical, thermal, and tensile properties, respectively. The thermal stability of the PLA-PBS blends enhanced on addition of MCC up to 1wt % due to their uniform dispersion in the polymer matrix. Tensile properties declined on addition of PBS and increased with MCC above (0.5 wt%) however except elongation at break increased on addition of PBS then decreased insignificantly on addition of MCC. Thus, PBS and MCC addition in PLA matrix decreases the brittleness, making it a potential contender that could be considered to replace plastics that are used for food packaging.
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http://dx.doi.org/10.3390/polym13030465DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7867041PMC
February 2021

Morphological, Structural, Thermal, Permeability, and Antimicrobial Activity of PBS and PBS/TPS Films Incorporated with Biomaster-Silver for Food Packaging Application.

Polymers (Basel) 2021 Jan 27;13(3). Epub 2021 Jan 27.

Department of Biochemistry, College of Science, King Saud University, PO Box 22452, Riyadh 11451, Saudi Arabia.

The development of antimicrobial film for food packaging application had become the focus for researchers and scientists. This research aims to study the characteristics and antimicrobial activity of novel biofilms made of poly (butylene succinate) (PBS) and tapioca starch (TPS) added with 1.5% or 3% of Biomaster-silver (BM) particle. In morphological examination, the incorporation of 3% BM particle was considerably good in forming well-structured PBS film. Meanwhile, the functional groups analysis revealed the 3% BM particle was effectively interacted with PBS molecular chains. The flame retard behavior of BM metal particle also helped in enhancing the thermal stability for pure PBS and PBS/TPS films. The nucleating effect of BM particles had improved the films crystallinity. Small pore size features with high barrier property for gas permeability was obtained for BM filled PBS/TPS films. From antimicrobial analysis, the BM particles possessed antimicrobial activity against three bacteria , , and in which PBS/TPS 3% BM film exhibited strong antimicrobial activity against all tested bacteria, however, PBS/TPS 1.5% BM film exhibited strong antimicrobial activity against only. Hence, the incorporation of BM into PBS/TPS film could be a sustainable way for developing packaging films to preserve food products.
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http://dx.doi.org/10.3390/polym13030391DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7869014PMC
January 2021

Fabrication and Characterization of Novel Poly(D-lactic acid) Nanocomposite Membrane for Water Filtration Purpose.

Nanomaterials (Basel) 2021 Jan 20;11(2). Epub 2021 Jan 20.

Office of Applied Research, International Clean Water Institute, Manassas, VA 20112, USA.

The development of membrane technology from biopolymer for water filtration has received a great deal of attention from researchers and scientists, owing to the growing awareness of environmental protection. The present investigation is aimed at producing poly(D-lactic acid) (PDLA) membranes, incorporated with nanocrystalline cellulose (NCC) and cellulose nanowhisker (CNW) at different loadings of 1 wt.% (PDNC-I, PDNW-I) and 2 wt.% (PDNC-II PDNW-II). From morphological characterization, it was evident that the nanocellulose particles induced pore formation within structure of the membrane. Furthermore, the greater surface reactivity of CNW particles facilitates in enhancing the surface wettability of membranes due to increased hydrophilicity. In addition, both thermal and mechanical properties for all nanocellulose filled membranes under investigation demonstrated significant improvement, particularly for PDNW-I-based membranes, which showed improvement in both aspects. The membrane of PDNW-I presented water permeability of 41.92 L/mh, when applied under a pressure range of 0.1-0.5 MPa. The investigation clearly demonstrates that CNWs-filled PDLA membranes fabricated for this investigation have a very high potential to be utilized for water filtration purpose in the future.
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http://dx.doi.org/10.3390/nano11020255DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7908979PMC
January 2021

Structural modeling and phylogenetic analysis for infectious disease transmission pattern based on maximum likelihood tree approach.

J Ambient Intell Humaniz Comput 2021 Jan 2:1-14. Epub 2021 Jan 2.

Biomedical Engineering Department, Faculty of Engineering, Helwan University, Cairo, Egypt.

The contagious disease transmission pattern outbreak caused a massive human casualty and became a pandemic, as confirmed by the World Health Organization (WHO). The present research aims to understand the infectious disease transmission pattern outbreak due to molecular epidemiology. Hence, infected patients over time can spread infectious disease. The virus may develop further mutations, and that there might be a more toxic virulent strain, which leads to several environmental risk factors. Therefore, it is essential to monitor and characterize patient profiles, variants, symptoms, geographic locations, and treatment responses to analyze and evaluate infectious disease patterns among humans. This research proposes the Evolutionary tree analysis (ETA) for the molecular evolutionary genetic analysis to reduce medical risk factors. Furthermore, The Maximum likelihood tree method (MLTM) has been used to analyze the selective pressure, which is examined to identify a mutation that may influence the infectious disease transmission pattern's clinical progress. This study also utilizes ETA with Markov Chain Bayesian Statistics (MCBS) approach to reconstruct transmission trees with sequence information. The experimental shows that the proposed ETA-MCBS method achieves a 97.55% accuracy, prediction of 99.56%, and 98.55% performance compared to other existing methods.
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http://dx.doi.org/10.1007/s12652-020-02702-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7778505PMC
January 2021

Comparative Chemical Profiles of the Essential Oils from Different Varieties of L.

Molecules 2020 Dec 29;26(1). Epub 2020 Dec 29.

Medicinal and Aromatic Plants Research Department, National Research Centre, 33 El Bohouth St., Dokki, Giza 12622, Egypt.

Guava () leaves are commonly used in the treatment of diseases. They are considered a waste product resulting from guava cultivation. The leaves are very rich in essential oils (EOs) and volatiles. This work represents the detailed comparative chemical profiles of EOs derived from the leaves of six guava varieties cultivated in Egypt, including Red Malaysian (RM), El-Qanater (EQ), White Indian (WI), Early (E), El-Sabahya El-Gedida (ESEG), and Red Indian (RI), cultivated on the same farm in Egypt. The EOs from the leaves of guava varieties were extracted by hydro-distillation and analyzed with GC-MS. The EOs were categorized in a holistic manner using chemometric tools. The hydro-distillation of the samples yielded 0.11-0.48% of the EO (). The GC-MS analysis of the extracted EOs showed the presence of 38 identified compounds from the six varieties. The sesquiterpene compounds were recorded as main compounds of E, EQ, ESEG, RI, and WI varieties, while the RM variety attained the highest content of monoterpenes (56.87%). The sesquiterpenes, -caryophyllene (11.21-43.20%), and globulol (76.17-26.42%) were detected as the major compounds of all studied guava varieties, while -nerolidol (0.53-10.14) was reported as a plentiful compound in all of the varieties except for the RM variety. A high concentration of D-limonene was detected in the EOs of the RM (33.96%), WI (27.04%), and ESEG (9.10%) varieties. These major compounds were consistent with those reported for other genotypes from different countries. Overall, the EOs' composition and the chemometric analysis revealed substantial variations among the studied varieties that might be ascribed to genetic variability, considering the stability of the cultivation and climate conditions. Therefore, this chemical polymorphism of the studied varieties supports that these varieties could be considered as genotypes of . It is worth mentioning here that the EOs, derived from leaves considered to be agricultural waste, of the studied varieties showed that they are rich in biologically active compounds, particularly -caryophyllene, -nerolidol, globulol, and D-limonene. These could be considered as added value for pharmacological and industrial applications. Further study is recommended to confirm the chemical variations of the studied varieties at a molecular level, as well as their possible medicinal and industrial uses.
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http://dx.doi.org/10.3390/molecules26010119DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7795193PMC
December 2020

Protection of ζ-crystallin by α-crystallin under thermal stress.

Int J Biol Macromol 2021 Jan 2;167:289-298. Epub 2020 Dec 2.

Department of Pharmacognosy, College of Pharmacy, King Saud University, Saudi Arabia.

Cataract is one of the major causes of blindness worldwide. Several factors including post-translational modification, thermal and solar radiations promote cataractogenesis. The camel lens proteins survive very harsh desert conditions and resist cataractogenesis. The folding and aggregation mechanism of camel lens proteins are poorly characterized. The camel lens contains three ubiquitous crystallins (α-, β-, and γ-crystallin) and a novel protein (ζ-crystallin) in large amounts. In this study, a sequence similarity search of camel α-crystallin with that of other organisms showed that the camel αB-crystallin consists of an extended N-terminal domain. Our results indicate that camel α-crystallin efficiently prevented aggregation of ζ-crystallin, with or without an obligate cofactor up to 89 °C. It performed a quick and efficient holdase function irrespective of the unfolding stage or aggregation. Camel α-crystallin exhibits approximately 20% chaperone activity between 30 and 40 °C and is completely activated above 40 °C. Camel α-crystallin underwent a single reversible thermal transition without loss of β-sheet secondary structure. Intrinsic tryptophan fluorescence and ANS binding experiments revealed two transitions which corresponded to activation of its chaperone function. In contrast to earlier studies, camel α-crystallin completely protected lens proteins during thermal stress.
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http://dx.doi.org/10.1016/j.ijbiomac.2020.11.183DOI Listing
January 2021

Effects of Accelerated Weathering on Degradation Behavior of Basalt Fiber Reinforced Polymer Nanocomposites.

Polymers (Basel) 2020 Nov 6;12(11). Epub 2020 Nov 6.

Department of Biochemistry, College of Science, King Saud University, P.O. Box 22452, Riyadh 11451, Saudi Arabia.

This work aims to give insight on the effect of accelerated weathering, i.e., the combination of ultraviolet (UV) exposure and water spraying, on the visual and mechanical properties of basalt fiber reinforced polymer (BFRP) composites. The solvent exchange method, sonication and high shear milling technique were used to prepare the nanocomposite laminates. Three types of laminates were fabricated, i.e., unmodified BFRP, nanosilica modified BFRP and graphene nanoplatelet (GNP) modified BFRP composites with the total fiber loading of 45 wt.%. Glass fiber reinforced polymer (GFRP) laminate was also prepared for performance comparison purposes between the natural and synthetic fibers. The laminates were exposed to UV with a total weathering condition of 504 h using a Quantum-UV accelerated weathering tester. The weathering condition cycle was set at 8 h 60 °C UV exposure and 4 h 50 °C condensation. The discoloration visual inspection on the tested specimen was observed under the optical microscope. The obtained results showed that the UV exposure and water absorption caused severe discoloration of the laminates due to photo-oxidation reaction. The effect of weathering conditions on tensile and flexural properties of unmodified BFRP composites indicated that the UV exposure and water absorption caused reduction by 12% in tensile strength and by 7% in flexural strength. It is also found that the reduction in tensile and flexural properties of nanomodified BFRP composites was smaller than the unmodified system. It concluded from this work, that the mineral based composites (i.e., BFRP) has high potential for structural applications owing to its better properties than synthetic based composites (i.e., GFRP).
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http://dx.doi.org/10.3390/polym12112621DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7694794PMC
November 2020

Circulation of dengue virus serotypes in hyperendemic region of New Delhi, India during 2011-2017.

J Infect Public Health 2020 Dec 2;13(12):1912-1919. Epub 2020 Nov 2.

Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India. Electronic address:

Background: Dengue fever has become a hampering menace in New Delhi India, since the disease has become hyperendemic, due to circulation of multiple serotypes of dengue virus (DENV). This hyperendemicity poses a greater risk of secondary infections in human health system. This is a major issue which leads to apprehension amongst the researchers and health organizations and thus requires regular epidemiological surveillance.

Methods: We analyzed the prevalence and serotypic distribution of dengue fever cases reported from the Southern part of New Delhi during continued surveillance from 2011 to 2017. The blood samples for the investigation were obtained from the patients suspected with dengue fever attending the OPD at a local Health Centre. The data for 2011-2016 was already published from our laboratory. The samples collected during 2017 were serotyped and characterized in the present study.

Results: A total of 565 samples (59%) were positive for DENV of 958 samples tested by RT-PCR during 7 years (2011-2017). Our study has shown that most infections were caused by DENV-2 during 2011-2015. The data has shown occurrence of all four serotypes of DENV during 2015 and predominance of DENV-3 in 2016 and 2017. Further, predominant combination of DENV-1 and DENV-2 was found in most of the co-infections. To the best of our knowledge this is the first study showing the epidemiological trend of dengue fever in reference to the circulating DENV serotypes and co-infections from a hyperendemic region of New Delhi during 2011-2017.

Conclusions: This hyperendemic pattern of DENV and instantaneous shift in circulation of its serotypes is likely pose a greater risk of secondary infections. Inclusion of comprehensive community and hospital surveillance of dengue fever will assist in formulation and implementation of effective control measures.
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http://dx.doi.org/10.1016/j.jiph.2020.10.009DOI Listing
December 2020

Effect of Antioxidants on Heavy Metals Induced Conformational Alteration of Cytochrome C and Myoglobin.

Protein Pept Lett 2021 ;28(1):31-42

Department of Biotechnology, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi-110062, India.

Background: The exposure to heavy metals due to unrestrained industrialization, pollution and non-degradability imposes a significant risk to human health. Proteins are prime targets of heavy metal stress, however, the underlying mechanisms and its impact on heme proteins is still not entirely clear.

Objective: To analyze the deleterious effect of heavy metals such as cadmium, chromium and mercury on conformation of two proteins namely, cytochrome c and myoglobin. The protective effect of glycine and ascorbic acid (animal origin), gallic acid and sesamol (plant origin) on heavy metal exposure was studied.

Methods: Far- and near-UV Circular Dichroism (CD) measurements monitored the changes in secondary and tertiary structure. Absorption Soret spectroscopy study revealed changes in heme-protein interaction. Peroxidase activity has been assayed to measure the absorption of tetraguaiacol. The interaction of heme proteins with different heavy metals was done using docking study.

Results: Far- and near-UV CD measurements reveal that heavy metals disrupt the secondary and tertiary structure of heme proteins. Antioxidants counteract the deleterious effect of heavy metals. Absorption spectroscopy revealed changes in the Soret region of these heme proteins. Changes in peroxidase activity was observed on addition of heavy metals and antioxidants. Molecular docking validated interaction of the heavy metals with proteins with a significant binding affinity (-2.3 kcal/- mol).

Conclusion: Heavy metals interfered and disrupted both the heme proteins and mercury showed the maximum deleterious effect, further, chromium showed detrimental effect at very small concentration. The antioxidants from animal origin exhibited better protective response than those from plant source.
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http://dx.doi.org/10.2174/0929866527666200610134442DOI Listing
April 2021

Structural stability and solubility of glycated camel lens ζ-crystallin.

Int J Biol Macromol 2020 May 4;158:384-393. Epub 2020 May 4.

Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia. Electronic address:

The camel has several biochemical, physiological, and anatomical features to withstand the harsh desert climate. Camel eye lens contains a novel protein (ζ-crystallin) in bulk quantity. Previous reports suggest that non-enzymatic glycation of eye lens proteins plays an important role in the etiology of cataract. In this study, we have characterized the role of glucose, fructose, and methylglyoxal (MGO) in the glycation of camel lens ζ-crystallin. From the results obtained, it was found that MGO reacted rapidly, fructose reacted moderately, and glucose was the least reactive even after prolonged incubation (>100 days). Glycation with MGO and fructose led to changes in the structure of ζ-crystallin, while glucose had no remarkable effect. The surface hydrophobicity did not change and no aggregates or amyloid fibrils were observed in the glycated ζ-crystallin. Moreover, the secondary structure of glycated ζ-crystallin remained similar after glycation. Our results suggested that due to natural adaptation, the camel lens protein ζ-crystallin retained its structure and solubility even after glycation to perform the single known function of the lens proteins: to focus unscattered light on the retina.
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http://dx.doi.org/10.1016/j.ijbiomac.2020.04.091DOI Listing
May 2020

Poziotinib and bovine serum albumin binding characterization and influence of quercetin, rutin, naringenin and sinapic acid on their binding interaction.

Spectrochim Acta A Mol Biomol Spectrosc 2020 Jul 1;235:118335. Epub 2020 Apr 1.

Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia. Electronic address:

Serum albumin is the major transporter protein present in systemic circulation and the ability to transport ligands can be influenced in presence of other ligands. This interaction can influence the pharmacodynamic and pharmacokinetic property of certain ligands. Spectroscopic and molecular docking studies were conducted to understand the poziotinib binding interaction to bovine serum albumin (BSA). Further, influence of different flavonoids (quercetin, rutin, naringenin and sinapic acid) on displacing poziotinib from BSA binding sites was also studied. The BSA and poziotinib followed a static quenching mechanism as the Stern-Volmer constant showed decrease (7.6 × 10-6.0 × 10) when the temperature increased from 298 K to 310 K. The BSA and poziotinib interaction was spontaneous and enthalpy driven. Involvement of Van der Waals forces and hydrogen bonding in the binding interaction was suggested on the basis of thermodynamic study results. Conformational changes were suggested in the BSA on its interaction with poziotinib based on fluorescence experimental data. The binding constant for BSA-poziotinib showed a maximum decrease in presence of quercetin followed by naringenin, rutin and sinapic acid respectively. Site displacement studies suggested binding of poziotinib site I of BSA.
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http://dx.doi.org/10.1016/j.saa.2020.118335DOI Listing
July 2020

Immunohistochemistry of IL-1β, IL-6 and TNF-α in spleens of mice treated with gold nanoparticles.

Saudi J Biol Sci 2020 Apr 30;27(4):1163-1168. Epub 2020 Jan 30.

Rohilkhand Medical College and Hospital, Bareilly 243006, India.

Gold nanoparticles (AuNPs) possess considerable biocompatibility and therefore gaining more attention for their biomedical applications. Previous studies have shown the transient increase in pro-inflammatory cytokines expression in different organs of rats and mice exposed to AuNPs. Structural changes in the spleen of mice treated with AuNPs have also been reported. This investigation was aimed to study the immunostaining of IL-1β, IL-6 and TNF-α in mice treated with different sizes of AuNPs. The animals were divided into 7 groups of 4 animals in each group. One group received saline and served as control. Two sets of three groups were treated with 5 nm, 20 nm and 50 nm diameter AuNPs. One set was sacrificed on day 1 and the other on day 7 following the AuNPs injections. Spleens were dissected out and promptly fixed in formalin for 3 days and then processed for IL-1β, IL-6 and TNF-α immunostaining using target-specific antibodies. The immunoreactivities of IL-1β and IL-6 were increased with the increase of AuNP size. The immunostaining of IL-1β in spleen of 20 nm AuNP treated mice was subsequently decreased on day 7 whereas it persisted in 50 nm AuNP group. The increase in the immunoreactivity of IL-6 on day 1 was decreased on day 7 in the spleens of mice treated with 20 nm or 50 nm AuNPs. The immunostaining of TNF-α was found to be negative in all the treatment groups. In conclusion, the size of AuNPs plays an important role in the expression of proinflammatory cytokines in mouse spleen; small size (5 nm) AuNPs caused minimal effect, whereas larger (50 nm) AuNPs produced intense immunostaining.
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http://dx.doi.org/10.1016/j.sjbs.2020.01.025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7105655PMC
April 2020

Structural and functional characterization of Tomato gene.

Saudi J Biol Sci 2020 Jan 14;27(1):352-357. Epub 2019 Oct 14.

Plant Production Department, Food Science and Agricultural College, King Saud University, POX 2455-11451, Riyadh, Saudi Arabia.

Small ubiquitin-related modifier () genes regulate various functions of target proteins through post-translational modification. The SUMO proteins have a similar 3-dimensional structure as that of ubiquitin proteins and occur through a cascade of enzymatic reactions. In the present study we have cloned a new SUMO gene from Tomato ( L.), cv Saudi-1, named gene by PCR using specific primers. This gene has SUMO member's features such as C-terminal diglycine (GG) motif as processing site by ULP (ubiquitin-like SUMO protease) and has SUMO consensus ΨKXE/D sequence. Phylogenetic analysis showed that gene is highly conserved and homologous to Potatoes and genes based on sequence similarity. Expression protein of gene found to be localized in the nucleus, cytoplasm, and nuclear envelop or nuclear pore complex. SUMO conjugating enzyme SCE1a with SlS-SUMO1 protein co-expressed and co-localized in nucleus and formed nuclear subdomains. This study reported that the gene is a member of SUMO family and its SUMO protein processing using GG motif and activate and transport to nucleus through Sumoylation system in the plant cell.
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http://dx.doi.org/10.1016/j.sjbs.2019.10.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6933199PMC
January 2020

Evolutionary analysis of the ON1 genotype of subtype a respiratory syncytial virus in Riyadh during 2008-16.

Infect Genet Evol 2020 04 24;79:104153. Epub 2019 Dec 24.

Protein Research Chair, Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia; Centre of Excellence in Biotechnology Research, Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia. Electronic address:

Respiratory syncytial virus is a leading cause of acute respiratory tract infection (ARI) in children worldwide. Limited information is available on molecular epidemiology of respiratory syncytial virus (RSV) from Saudi Arabia. An attempt was made to identify and characterize RSV strains in nasopharyngeal aspirates collected from hospitalized symptomatic ARI pediatric patients with <5 years of age from Riyadh, Saudi Arabia during 2016. All the samples (n = 100) were tested for RSV by real time PCR. The RSV strains were characterized by sequencing of the second hypervariable region of G protein gene. The study sequences along with the previously reported strains from Saudi Arabia were assessed for mutational, glycosylation, phylogenetic, selection pressure and entropy analyses. Fifty percent of the nasopharyngeal aspirates were positive for RSV. The RSVA (72%) predominated as compared to RSVB (24%) during the study. The study RSVA strains (n = 29) clustered into NA1 and ON1 genotypes whereas all the RSVB sequences (n = 5) were in BA genotype by phylogenetic analysis. Interestingly, 97% of RSVA sequences (n =28) clustered into ON1 genotype with 72 bp duplication in the G protein gene. Numerous mutations, variable N-/O-glycosylation sites and purifying selections were observed in the ON1 genotype. Positive selection with high entropy value was observed for three codons in ON1 (247, 262 and 274 amino acids) indicating higher probability of variations at these positions. Our study shows the progressive emergence and predominance of the ON1 genotype in Riyadh, Saudi Arabia during 2008-16. ON1 genotype almost replaced the previously circulating RSVA strains in this region during this period. Contribution of host genetic and immune factors towards disease severity of the ON1 genotype needs to be investigated in future studies. RSV surveillance in future elaborate investigations are needed in this region to understand its disease burden, evolutionary trajectory and circulation dynamics warranting steps towards vaccine development.
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http://dx.doi.org/10.1016/j.meegid.2019.104153DOI Listing
April 2020

Association of vitamin D receptor TaqI and ApaI genetic polymorphisms with nephrolithiasis and end stage renal disease: a meta-analysis.

BMC Med Genet 2019 12 10;20(1):193. Epub 2019 Dec 10.

Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia.

Background: The deficiency of vitamin D receptor (VDR) or its ligand, vitamin D3, is linked to the development of renal diseases. The TaqI (rs731236) and ApaI (rs7975232) polymorphisms of VDR gene are widely studied for their association with renal disease risk. However, studies have largely been ambiguous.

Methods: Meta-analysis was carried out to clarify the association of TaqI (2777 cases and 3522 controls) and ApaI (2440 cases and 3279 controls) polymorphisms with nephrolithiasis (NL), diabetic nephropathy (DN) and end stage renal disease (ESRD).

Results: The VDR TaqI C-allele under allele contrast was significantly associated with ESRD in both fixed effect and random effect models, and ApaI C-allele with ESRD only under fixed effect model. Cochrane Q-test showed no evidence of heterogeneity for TaqI polymorphism and a significant heterogeneity for Apa I polymorphism. No publication bias was observed for both the polymorphisms.

Conclusions: The present meta-analysis identifies TaqI and ApaI polymorphisms of VDR gene as risk factors for renal diseases.
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http://dx.doi.org/10.1186/s12881-019-0932-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6902508PMC
December 2019

Seroprevalence and molecular characterization of Brucella species in naturally infected cattle and sheep.

Prev Vet Med 2019 Nov 27;171:104756. Epub 2019 Aug 27.

Center of Excellence in Biotechnology Research, King Saud University, POX 2455-11451, Riyadh, Saudi Arabia; Biochemistry Department, Science College, King Saud University, POX 2455-11451, Riyadh, Saudi Arabia.

Brucellosis is one of the most economically significant infectious diseases in Egypt. The study aimed to assess the seroprevalence by indirect ELISA by examining serum samples from 720 cattle and 320 sheep and detection and characterization of Brucella spp. from 24 clinical samples (placenta) by bacterial culture (BC) and PCR targeting bcsp31 gene. The seroprevalence was 16.7% and 16.25% in cattle and sheep, respectively. There was a significant association (P < 0.05) between the seroprevalence of brucellosis and sex at the level of cattle and age at the sheep level, where seroprevalence was 18.7% in female cattle and 22% in sheep > 2 years. Likewise, seroprevalence was significantly (P < 0.05) different among locations for cattle. Of the 24 clinical samples tested by BC, B. abortus was isolated and identified in 100% of clinical samples. Using PCR, all Brucella strains were positive (100%) regarding bcsp31gene. Nucleotide analyses of seven bcsp31 sequences of the identified strains revealed 99.3-100% identity, with one nucleotide divergence. These results provide an insight into the brucellosis, particularly with the detection of B. abortus from sheep, therefore, further wide epidemiological studies are needed to develop appropriate prevention and control strategies.
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http://dx.doi.org/10.1016/j.prevetmed.2019.104756DOI Listing
November 2019

An efficient methodology for the purification of date palm peroxidase: Stability comparison with horseradish peroxidase (HRP).

Saudi J Biol Sci 2019 Feb 12;26(2):301-307. Epub 2018 Apr 12.

Center of Excellence in Biotechnology Research, Dept. Of Biochemistry, College of Science, King Saud University, Saudi Arabia.

In the present study, Peroxidase from date palm () leaves was purified to homogeneity by three-step procedure including aqueous two-phase system, hydrophobic and Ion-exchange chromatography. The enzyme migrated as single band on SDS-PAGE giving molecular weight of 68 ± 3 kDa. The purification factor for purified date palm peroxidase was 68 with high 41% yield. Enzymatic assays together with far-UV circular dichroism (CD), intrinsic and extrinsic fluorescence studies were carried out to monitor the structural stability of date palm and horseradish peroxidase (HRP) against various pH and temperatures. Activity measurements illustrated different pH stability for date palm and HRP. Both peroxidases are more susceptible to extreme acidic conditions as suggested by 4 & 15 nm red shift in date palm and HRP, respectively. Secondary structure analysis using far UV-CD exhibited predominance of α-helical (43.8%) structure. Also, pH induces loss in the secondary structure of date palm peroxidase. Thermal stability analysis revealed date palm peroxidase is more stable in comparison to HRP. In summary, date palm peroxidases could be promising enzymes for various applications where extreme pH and temperature is required.
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http://dx.doi.org/10.1016/j.sjbs.2018.04.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6717102PMC
February 2019

The plant flavonoid, fisetin alleviates cigarette smoke-induced oxidative stress, and inflammation in Wistar rat lungs.

J Food Biochem 2019 08 28;43(8):e12962. Epub 2019 Jun 28.

Research Chair for Biomedical Applications of Nanomaterials, Biochemistry Department, College of Science, King Saud University, Riyadh, Saudi Arabia.

In the present study, we tested the antioxidant and anti-inflammatory potential of the plant flavonoid, fisetin against cigarette smoke-induced oxidative stress, and inflammation in rat lungs. Male Wistar rats were chronically exposed to cigarette smoke (CS) with or without administration of fisetin. Fisetin administration to CS-exposed rats resulted in a significant reduction in neutrophils and macrophages in bronchoalveolar lavage fluid as well as malondialdehyde, 3-nitrotyrosine, 8-isoprostane, tumor necrosis factor-alpha, interleukin-1beta, granulocyte macrophage-colony stimulating factor, interleukin-4, and interleukin-10 levels in lung tissues compared to those in CS-exposed rats not treated with fisetin. Fisetin also significantly augmented lung hemoxinase-1, glutathione peroxidase-2, reduced glutathione, superoxide dismutase, nitric oxide, and nuclear factor erythroid 2-related factor (Nrf2) levels in CS-exposed rats. In addition, a marked reversal in CS-induced histopathological changes was noted in fisetin-treated rats. Collectively, these data demonstrate the potential of fisetin to blunt CS-induced oxidative stress and inflammation in the lung and to prevent tissue damage via the Nrf2-mediated upregulation of antioxidant gene expression. PRACTICAL APPLICATIONS: In the present study, we found that the plant flavonoid, fisetin significantly abrogated the oxidative stress, inflammation, and tissue damage induced by cigarette smoke, a powerful pro-oxidant in rat lungs. Additionally, fisetin markedly reversed cigarette smoke-induced increases in neutrophil and macrophage cell populations in bronchoalveolar lavage fluid. These findings are particularly significant considering the association of cigarette smoking with increased oxidative stress and inflammation, which are central to the pathologies of a wide variety of chronic diseases including chronic obstructive pulmonary disease, cancer, and cardiovascular diseases. Therefore, the present work underscores the beneficial effects of the regular consumption of plant-based foods with medicinal properties for the effective prevention of these chronic diseases.
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http://dx.doi.org/10.1111/jfbc.12962DOI Listing
August 2019

Effect of cetyltrimethylammonium bromide (CTAB) on the conformation of a hen egg white lysozyme: A spectroscopic and molecular docking study.

Spectrochim Acta A Mol Biomol Spectrosc 2019 Aug 24;219:313-318. Epub 2019 Apr 24.

King Saud University, Protein Research Chair, Department of Biochemistry, College of Science, Riyadh 11451, Saudi Arabia.

The interactions between cetyltrimethylammonium bromide (CTAB) and hen egg white lysozymes (HEWL) was carried out to investigate protein-surfactant interaction mechanisms while both exist in the overall same charged state. The interactions between CTAB and the HEWL were examined with circular dichroism (CD), dynamic light scattering (DLS), fluorescence spectroscopy, and computational docking at a pH9.0 at room temperature. The far-UV CD and fluorescence results revealed that CTAB at concentrations from 0.15 to 10.0mM influenced the secondary as well as the tertiary structure of HEWL. The secondary structure of the HEWL was retained, while the tertiary structure of the HEWL was disrupted in the CTAB-treated samples at pH9.0. The hydrodynamic radii of the HEWL were also expanded in the presence of CTAB. Molecular docking studies showed that CTAB formed one electrostatic and four hydrophobic interactions, as well as one carbon hydrogen bond with HEWL. The data obtained from spectroscopic and computational studies demonstrated that the positively charged head and 18‑carbon alkyl chain of the CTAB interacted through weak electrostatic and strong hydrophobic interactions.
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http://dx.doi.org/10.1016/j.saa.2019.04.062DOI Listing
August 2019

Increased CD5+ B-cells are associated with autoimmune phenomena in lepromatous leprosy patients.

J Infect Public Health 2019 Sep - Oct;12(5):656-659. Epub 2019 Mar 20.

Center of Excellence in Biotechnology Research, Biochemistry Department, KSU, P.O. Box 2455, 11451, Saudi Arabia.

Background And Objective: Leprosy is a chronic slowly progressive infection caused by Mycobacterium leprae that primarily affects the skin and peripheral nerves. Lepromatous leprosy is characterized by absence of T-cell responses to M. leprae and advanced clinical disease. It is frequently associated with the presence of autoantibodies, which might be related to CD19CD5 and CD19CD5 B lymphocyte percentages. Therefore, the aim of this study was to evaluate the percentages of CD19CD5 and CD19CD5 B cell subsets as well as the total B cells in lepromatous leprosy patients.

Materials And Methods: Twenty lepromatous leprosy patients and ten healthy subjects served as control were included in this study. Venous blood samples were analyzed by flow cytometry to determine the B cell subsets and total B cell percentages.

Results: Compared to healthy controls, the percentages of CD19CD5 B cell subset and total B cells were found to be significantly higher in the patient group. While, the percentage of CD19CD5 B cell subset was found to be higher in the patient group than the control without any significantly difference. Regarding the eye affection, the percentage of total B cells was observed to be significantly higher in affected patients compared to the non-affected group.

Conclusion: The observed significant increases in CD19CD5 and total B cell percentages in patients with lepromatous leprosy suggests a possible role of these cells in the disorganized protective immune response as well as the development of eye complications in these patients.
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http://dx.doi.org/10.1016/j.jiph.2019.03.001DOI Listing
January 2020

Size and time-dependent induction of proinflammatory cytokines expression in brains of mice treated with gold nanoparticles.

Saudi J Biol Sci 2019 Mar 29;26(3):625-631. Epub 2018 Sep 29.

Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia.

Gold nanoparticles (GNPs) are among the ideal nano-sized materials for medical applications such as imaging and drug delivery. Considering the significance of recent reports on acute phase induction of inflammatory mediators by GNPs, we studied the effect of GNPs on proinflammatory cytokines gene expression in mouse brain. Group 1 served as control whereas groups 2-4 were given only one intraperitoneal dose of 5, 20 and 50 nm GNPs, respectively and sacrificed after 24 h. The animals in groups 5-7 also received the same treatment but sacrificed after 7 days. Groups 8-10 received two injections of GNPs (5, 20 and 50 nm, respectively), first at the beginning of study and second on day 6, and sacrificed on day 7. Total RNA was extracted from the cerebral tissue and analyzed for the gene expressions of IL-1β, IL-6 and TNF-α. A single injection of 5 nm diameter GNPs significantly increased the mRNA expression of IL-1β and IL-6 in mouse brain on day 7, which was not augmented by the second dose of the same GNPs. Larger size GNPs (20 nm and 50 nm) did not cause any significant change in the expression of proinflammatory cytokines in mouse brain. In conclusion, systemic administration of small sized GNPs (5 nm) induced a proinflammatory cascade in mouse brain indicating a crucial role of GNPs size on immune response. It is important to use the right sized GNPs in order to avoid an acute phase inflammatory response that could be cytotoxic or interfere with the bioavailability of nanomaterials.
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http://dx.doi.org/10.1016/j.sjbs.2018.09.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6408702PMC
March 2019

Food additive dye (quinoline yellow) promotes unfolding and aggregation of myoglobin: A spectroscopic and molecular docking analysis.

Spectrochim Acta A Mol Biomol Spectrosc 2019 May 13;214:216-226. Epub 2019 Feb 13.

Department of Chemistry, Collage of Science Princess Noura Bint Abdul Rahman University, Riyadh, Saudi Arabia. Electronic address:

Protein aggregation leads to vast conformational changes and plays a key role in the pathogenesis of various neurodegenerative diseases including Alzheimer's and Parkinson's. In the current piece of work, we have explored the interaction of quinoline yellow (QY) with myoglobin (Mb) at two different pH (3.5 and 7.4). Various spectroscopic techniques such as turbidity, Rayleigh light scattering (RLS), UV-Vis absorbance, fluorescence resonance energy transfer (FRET), far UV-CD along with transmission electron microscopy (TEM) and molecular docking have been utilized to characterize dye-induced aggregation in Mb. Binding results showed that interaction between QY and myoglobin is spontaneous and static in nature with high K value of 2.14 × 10 M. On the other hand, thermodynamics studies (∆H & ∆S) revealed that complex formation was driven by hydrogen and Van der Walls forces. Molecular docking analysis showed strong binding affinity (K = 4.95 × 10 M) between QY and Mb at Pro100, Ile101, Lys102, Glu105, Glu136, Arg139, Lys140, and Ala143 residues. The intrinsic fluorescence and circular dichroism studies indicated that QY induced conformational changes in Mb at pH 3.5. Turbidity and RLS studies showed aggregation of Mb in the presence of QY (0.2-5 mM). Moreover, kinetics data revealed nucleation independent aggregation of myoglobin in the presence of QY. TEM analysis further established amorphous nature of Mb aggregate induced by QY. At pH (7.4), QY was unable to induce aggregation in myoglobin; it might be due to repulsive nature of negatively charged dye and myoglobin or partially altered states of protein could be pre-requisite for binding and aggregation.
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http://dx.doi.org/10.1016/j.saa.2019.01.090DOI Listing
May 2019

Different conformational states of hen egg white lysozyme formed by exposure to the surfactant of sodium dodecyl benzenesulfonate.

Int J Biol Macromol 2019 May 22;128:54-60. Epub 2019 Jan 22.

Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.

The aim of this study was to investigate the effects of sodium dodecyl benzenesulfonate (SDBS) on hen egg white lysozyme (HEWL) fibrillogenesis at pH 7.4. HEWL fibrillogenesis in the presence of SDBS was characterized using several spectroscopic techniques (turbidity, light scattering, intrinsic fluorescence, ThT binding assay, ThT kinetics, far-UV CD, and transmission electron mmicroscopy). The turbidity and light scattering data revealed that SDBS induces aggregation in HEWL in dose-dependent manner. HEWL aggregation was seen at low SDBS concentrations (0.03 to 0.5 mM) but it was not observed at concentrations of SDBS at >0.6 mM. The ThT and TEM data clearly showed that the aggregates formed in the presence of SDBS had an amyloid-like morphology. From the CD analysis it was clear that low SDBS concentrations decreases the α-helical content while the β-sheet content increased. As the SDBS concentration further increased, the α-helical content increased again. The ThT kinetics analysis revealed that the HEWL monomer directly converted into the amyloid fibril without lag phase. All the spectroscopic and microscopic results support the finding that low concentrations of SDBS stimulate fibrillogenesis in HEWL, and that no fibrillogenesis occurs at higher SDBS concentrations.
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http://dx.doi.org/10.1016/j.ijbiomac.2019.01.097DOI Listing
May 2019

Allura red rapidly induces amyloid-like fibril formation in hen egg white lysozyme at physiological pH.

Int J Biol Macromol 2019 Apr 14;127:297-305. Epub 2019 Jan 14.

Department of Food Science and Nutrition, Faculty of Food and Agricultural Sciences, King Saud University, Riyadh, Saudi Arabia.

Allura red (AR) is an artificial azo dye mostly used in food industries and has potential health risks. We examined the role of AR in amyloidogenesis using hen egg white lysozyme (HEWL) at pH 7.0. The amyloidogenic induction properties of AR in HEWL were identified by circular dichroism (CD), turbidity, intrinsic fluorescence, light scattering, transmission electron microscopy (TEM), and molecular dynamic simulation studies. Turbidity and light scattering measurements showed that HEWL becomes aggregated in the presence of 0.03-15.0 mM of AR at pH 7.0 but not at very low AR concentrations (0.01-0.28 mM). However, AR-induced aggregation is a kinetically rapid process, with no observable lag phase and saturation within 6 s. The kinetics results suggested that the HEWL aggregation induced by AR is very rapid. The CD results demonstrated that the total β-sheet content of HEWL was increased in the AR treated samples. The TEM results are established that AR-induced aggregates had amyloid-like structures. Molecular dynamics simulations analysis showed that the bound AR-HEWL structures were highly favored compared to unbound structures. The mechanism of AR-induced amyloid fibril formation may involve electrostatic, hydrogen bonding, and hydrophobic interactions.
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http://dx.doi.org/10.1016/j.ijbiomac.2019.01.049DOI Listing
April 2019

Incense smoke exposure augments systemic oxidative stress, inflammation and endothelial dysfunction in male albino rats.

Toxicol Mech Methods 2019 Mar 16;29(3):211-218. Epub 2019 Jan 16.

b Biochemistry Department, College of Science , King Saud University , Riyadh , Saudi Arabia.

Incense smoke is reported to increase cardiovascular disease (CVD) risk in exposed individuals. However, the mechanism underlying the toxic effect of incense smoke on cardiovascular system is unclear. To test this, we chronically exposed male albino rats to two different types of Arabian incense smoke and studied their effects on oxidative stress, inflammation, and endothelial function. Rats exposed to either of incense smoke showed a significant increase in malondialdehyde (MDA) and a significant decline in superoxide dismutase (SOD) and reduced glutathione (GSH). Endothelial functional marker, nitric oxide (NO) was significantly decreased while endothelin-1 was significantly increased in rats exposed to both the incense types. Incense smoke exposure also led to a significant increase in chemokines and inflammatory mediators including monocyte chemoattractant protein-1 (MCP-1), granulocyte-macrophage-colony stimulating factor (GM-CSF), regulated on activation normal T cell expressed and secreted (RANTES), interleukin-4 (IL-4), C-reactive protein (CRP), and tumor necrosis factor-alpha (TNF-α). Besides, incense smoke-exposed rats demonstrated a significant increase in the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecules-1 (VCAM-1), and E-selectin. Importantly, cessation of incense smoke exposure for 30 days led to a significant reversal in the levels of all the studied markers. Collectively, this study describes oxidative stress, endothelial dysfunction, and inflammation as possible underlying mechanisms in the toxic effects of incense smoke on increased CVD risk in exposed individuals. Findings also underscore that avoiding incense smoke exposure may have beneficial health effects.
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http://dx.doi.org/10.1080/15376516.2018.1544681DOI Listing
March 2019

Monomeric Camelus dromedarius GSTM1 at low pH is structurally more thermostable than its native dimeric form.

PLoS One 2018 10;13(10):e0205274. Epub 2018 Oct 10.

Department of Biochemistry, Protein Research Chair, College of Science, King Saud University, Riyadh, Saudi Arabia.

Glutathione S‒transferases (GSTs) are multifunctional enzymes that play an important role in detoxification, cellular signalling, and the stress response. Camelus dromedarius is well-adapted to survive in extreme desert climate and it has GSTs, for which limited information is available. This study investigated the structure-function and thermodynamic properties of a mu-class camel GST (CdGSTM1) at different pH. Recombinant CdGSTM1 (25.7 kDa) was expressed in E. coli and purified to homogeneity. Dimeric CdGSTM1 dissociated into stable but inactive monomeric subunits at low pH. Conformational and thermodynamic changes during the thermal unfolding pathway of dimeric and monomeric CdGSTM1 were characterised via a thermal shift assay and dynamic multimode spectroscopy (DMS). The thermal shift assay based on intrinsic tryptophan fluorescence revealed that CdGSTM1 underwent a two-state unfolding pathway at pH 1.0-10.0. Its Tm value varied with varying pH. Another orthogonal technique based on far-UV CD also exhibited two-state unfolding in the dimeric and monomeric states. Generally, proteins tend to lose structural integrity and stability at low pH; however, monomeric CdGSTM1 at pH 2.0 was thermally more stable and unfolded with lower van't Hoff enthalpy. The present findings provide essential information regarding the structural, functional, and thermodynamic properties of CdGSTM1 at pH 1.0-10.0.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0205274PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6179282PMC
April 2019