Biology subjects

Ahmad, R.

Publications and source records attributed to Ahmad, R..

43 records · Page 3Linked to original sources

bioRxiv2020

Crocus Sativus and Its Active Compound, Crocin Inhibits the Endothelial Activation and Monocyte-Endothelial Cells Interaction in Stimulated Human Coronary Artery Endothelial Cells

Crocus sativus L. or saffron has been shown to have anti-atherogenic effects. However, its effects on key events in atherogenesis such as endothelial activation and monocyte-endothelial cell binding in lipolysaccharides (LPS)-stimulated in vitro model have not been extensively studied. ObjectivesTo investigate the effects of saffron and its bioactive derivative crocin on the gene and protein expressions of biomarkers of endothelial activation in LPS stimulated human coronary artery endothelial cells (HCAECs). MethodologyHCAECs were incubated with different concentrations of aqueous ethanolic extracts of saffron and crocin together with LPS. Protein and gene expressions of endothelial activation biomarkers were measured using ELISA and qRT-PCR, respectively. Adhesion of monocytes to HCAECs was detected by Rose Bengal staining. Methyl-thiazol-tetrazolium assay was carried out to assess cytotoxicity effects of saffron and crocin. ResultsSaffron and crocin up to 25.0 and 1.6 g/ml respectively exhibited >85% cell viability. Saffron treatment reduced sICAM-1, sVCAM-1 and E-selectin proteins (concentrations: 3.13, 6.25, 12.5 and 25.0 g/ml; 3.13, 12.5 and 25.0 g/ml; 12.5 and 25.0, respectively) and gene expressions (concentration: 12.5 and 25.0g/ml; 3.13, 6.25 and 25.0 g/ml; 6.25, 12.5 25.0; respectively). Similarly, treatment with crocin reduced protein expressions of sICAM-1, sVCAM-1 and E-selectin (concentration: 0.2, 0.4, 0.8 and 1.6 g/ml; 0.4, 0.8 and 1.6 g/ml; 0.8 and 1.6 g/ml; respectively] and gene expression (concentration: 0.8 and 1.6 g/ml; 0.4, 0.8 and 1.6 g/ml; and 1.6 g/ml, respectively). Monocyte-endothelial cell interactions were reduced following saffron treatment at concentrations 6.3, 12.5 and 25.00 g/ml. Similarly, crocin also suppressed cellular interactions at concentrations 0.04, 0.08, 1.60 g/ml. ConclusionSaffron and crocin exhibits potent inhibitory action for endothelial activation and monocyte-endothelial cells interaction suggesting its potential anti-atherogenic properties.

pathology↗

bioRxiv2019

The association of self-reported sleep quality and obesity in Kuwait using the Pittsburgh Sleep Quality Index (PSQI)

Obesity is an epidemic problem facing Kuwait and other neighboring countries within the region. Lifestyle and social structure in this region differ in comparison to the western world. The hot chalinging climate favor night time activities while working hours still force a stringent early attendence. This study is specifically conducted for Kuwaits population to investigate the link between Sleep Quality (SQ) and obesity. A cross-sectional study was conducted for a sample of 1002 participants. Structured questionnaires were used in the study as a tool of research. The participants were asked about their sleep habits, sleep problems, medications, job nature and demographics. All participants consented prior to conducting the survey. In order to measure sleep quality (SQ), the Pittsburgh Sleep Quality Index (PQSI) was used. Statistical analysis was conducted between variables and the data were compared using either two-tailed t-test or one-way ANOVA followed by Tukeys multiple comparison test. Pearsons correlation coefficient r was used to assess linear dependence. 59.4% of Kuwait population reported a PSQI score higher than 5, with 57.3% of the participants reporting less than 6 hours of sleep per day. The presented data shows that both sleep quality and sleep duration are considered inadequate in comparison to international sleep quality standards. None the less, we also found strong a significant association between sleep quality and its component and obesity, while other factors such as age and gender were found insignificant. These finding suggest that sleep deprivation and disturbance could be an indirect inducing factor of obesity in Kuwait. The researchers are of the view that there is a need for more study in the area of obesity and SQ in order to handle the obesity epidemic in the country.

evolutionary biology↗

bioRxiv2019

Bioactivity-guided isolation of rosmarinic acid as a principle bioactive compound from the butanol extract of Isodon rugosus against pea aphid, Acyrthosiphon pisum

Aphids are agricultural pest insects that transmit viruses and cause feeding damage on a global scale. Current pest control involving the excessive use of synthetic insecticides over decades has led to multiple forms of aphid resistance to most classes of insecticides. In nature, plants produce secondary metabolites during their interaction with insects and these metabolites can act as toxicants, antifeedants, anti-oviposition agents and deterrents towards the insects. In a previous study, we demonstrated that the butanol fraction from a crude methanolic extract of an important plant species, Isodon rugosus showed strong insecticidal activity against the pea aphid, Acyrthosiphon pisum. It was however not known as which compound was responsible for such activity. To further explore this finding, current study aimed to exploit a bioactivity-guided strategy to isolate and identify the active compound in the butanol fraction of I. rugosus. As such, reversed-phase flash chromatography, acidic extraction and different spectroscopic techniques were used to isolate and identify the new compound, rosmarinic acid as the bioactive compound in I. rugosus. Insecticidal activity of rosmarinic acid was carried out using standard protocols on A. pisum. The data was analyzed using qualitative and quantitative statistical approaches. Considering that a very low concentration of this compound (LC90 = 5.4 ppm) causes significant mortality in A. pisum within 24 h, rosmarinic acid could be exploited as a potent insecticide against this important pest insect. Furthermore, I. rugosus is already used for medicinal purposes and rosmarinic acid is known to reduce genotoxic effects induced by chemicals, hence it is expected to be safer compared to the current conventional pesticides. While this study highlights the potential of I. rugosus as a possible biopesticide source against A. pisum, it also provides the basis for further exploration and development of formulations for effective field application.

plant biology↗

bioRxiv2018

A schizophrenia risk gene, NRGN, bidirectionally modulates synaptic plasticity via regulating the neuronal phosphoproteome

NRGN is a schizophrenia risk gene identified in recent genetic studies, encoding a small neuronal protein, neurogranin (Ng). Individuals carrying a risk variant of NRGN showed decreased hippocampal activation during contextual fear conditioning. Furthermore, the expression of Ng was reduced in the post-mortem brains of schizophrenic patients. Using the mouse model, we found that the translation of Ng in hippocampus is rapidly increased in response to novel context exposure, and this up-regulation is required for encoding contextual memory. The extent and degree of the effect that altered Ng expression has on neuronal cellular functions are largely unknown. Here, we found that Ng bidirectionally regulates synaptic plasticity in the hippocampus. Elevated Ng levels facilitated long-term potentiation (LTP), whereas decreased Ng levels impaired LTP. Quantitative phosphoproteomic analysis revealed that decreasing Ng caused a significant shift in the phosphorylation status of postsynaptic density proteins, highlighting clusters of schizophrenia- and autism-related genes. In particular, decreasing Ng led to the hypo-phosphorylation of NMDAR subunit Grin2A at newly identified sites, resulting in accelerated decay of NMDAR-mediated channel currents. blocking protein phosphatase PP2B activity rescued the accelerated synaptic NMDAR current decay and the impairment of LTP caused by decreased Ng levels, suggesting that enhanced synaptic PP2B activity led to the deficits. Taken together, our work suggests that altered Ng levels under pathological conditions affect the phosphorylation status of neuronal proteins by tuning PP2B activity and thus the induction of synaptic plasticity, revealing a novel mechanistic link of a schizophrenia risk gene to cognitive deficits.

neuroscience↗

bioRxiv2018

Nanopore-based DNA sequencing in clinical microbiology: preliminary assessment of basic requirements

AimIdentify basic requirements for a metagenomic nanopore sequencing protocol permitting frequent application in a clinical microbiology daily routine diagnostic setting.\n\nBackgroundNanopore sequencing with the Oxford Nanopore Technologies MinION device has a potential to markedly improve clinical diagnosis of infections. Reports have emerged recently that it may provide direct-from-clinical-sample information; for example, with urine samples, bronchial tuberculosis samples and orthopedic prostheses. However, the ideal protocol for clinical use remains to be determined, especially relating to detection of relevant pathogen quantities and to finding a reasonable level of economic costs.\n\nResultsMinION can provide qualitatively and quantitatively correct identification of multiple species in metagenomics samples. For detection of clinically relevant quantities of bacteria (on a nanogram DNA level) there is a need for carrier DNA. Importantly, high-purity DNA and a naive MinION flow cell seem to be critical parameters.\n\nConclusionsOur results suggest that high-purity clinical sample DNA, addition of carrier DNA and a naive flow cell are critical factors for clinical use of MinION. A relatively high error rate may limit detection of antimicrobial resistance genes, and a realistic level of costs will require availability of a price-reduced and single-use flowcell.

microbiology↗

bioRxiv2018

Synthesis, Biological Activity and Molecular Docking of New Tricyclic Series as α-glucosidase Inhibitors

Diabetes is an emerging metabolic disorder. -Glucosidase inhibitors, such as acarbose, delay the hydrolysis of carbohydrates by interfering with the digestive enzymes. This action decreases the glucose absorption and the postprandial glucose level. We have synthesized 25 tricyclic 2-phenoxypyrido[3,2-e][1,2,4]triazolo[1,5-a]pyrimidin-5(4H)-ones hybrids and evaluated their -glucosidase inhibitory activity. Compounds 6h and 6d have shown stronger activity than that of acarbose. Compound 6h exhibited the highest inhibition with an IC50 of 104.07 mM. Molecular modelling studies revealed that compound 6h inhibits -glucosidase due to the formation of a stable ligand--glucosidase complex and extra hydrogen bond interactions, and directed in the binding site by Trp329.

biochemistry↗

bioRxiv2018

Brain-Specific Deletion of GIT1 Impairs Cognition and Alters Phosphorylation of Synaptic Protein Networks Implicated in Schizophrenia Susceptibility

Despite tremendous effort, the molecular and cellular basis of cognitive deficits in schizophrenia remain poorly understood. Recent progress in elucidating the genetic architecture of schizophrenia has highlighted the association of multiple loci and rare variants that may impact susceptibility. One key example, given their potential etiopathogenic and therapeutic relevance, is a set of genes that encode proteins that regulate excitatory glutamatergic synapses in brain. A critical next step is to delineate specifically how such genetic variation impacts synaptic plasticity and to determine if and how the encoded proteins interact biochemically with one another to control cognitive function in a convergent manner. Towards this goal, here we study the roles of GPCR-kinase interacting protein 1 (GIT1), a synaptic scaffolding and signaling protein with damaging coding variants found in schizophrenia patients, as well as copy number variants found in patients with neurodevelopmental disorders. We generated conditional neural-selective GIT1 knockout mice and find that these mice have deficits in fear conditioning learning and spatial memory. Using global quantitative phospho-proteomics, we revealed that GIT1 deletion in brain perturbs specific networks of GIT1-interacting synaptic proteins. Importantly, several schizophrenia and neurodevelopmental disorder risk genes are present within these networks. We propose that GIT1 regulates the phosphorylation of a network of synaptic proteins and other critical regulators of neuroplasticity, and that perturbation of these networks may contribute to cognitive deficits observed in schizophrenia and neurodevelopmental disorders.

neuroscience↗