Susanna Tiratsuyan - Academia.edu (original) (raw)

Papers by Susanna Tiratsuyan

Nanomedicine, Feb 13, 2024

IFMBE proceedings, Sep 13, 2023

Cell Biochemistry and Biophysics

Физиология растений, 2016

A series of pyridazine derivatives was synthesized and some of them showed a growth stimulatory a... more A series of pyridazine derivatives was synthesized and some of them showed a growth stimulatory activity during preliminary screening. Their effects on germination, morphogenesis, peroxidase activity and lignan content were tested on common bean (Phaseolus vulgaris L.) plants. 2-[4-(6-ethoxy-pyridazin-3-ylsulfanyl)-6-ethylamino-[1,3,5]triazin-2-ylsulfanyl]-acetamide (C8) accelerated flowering and fruit production. In these plants, total lignan amount in the leaves correlated with the corresponding peroxidase activities. This compound can be recommended against the lodging of crops. Like IAA, 2-(6-ethoxy-pyridazin-3-yl)-isothiourea hydrochloride (C3) stimulated adventitious root growth with necrotic transformation of the bottom stem node. It promoted growth of leaves, the early reproductive development and pod formation. Preparations C3 and C8 can be recommended for the shortening of the juvenile time. In plants treated with each of these compounds, the highest content of lignans was recorded possibly relating to type I "non-host"-like plants resistance. 2-(6chloro-pyridazin-3-yl)-isothiourea hydrochloride (C2) exerted a stimulatory effect on the growth of vegetative organs.

The antioxidative potentials of extracts of Hypericum perforatum from Tavush region of Armenia we... more The antioxidative potentials of extracts of Hypericum perforatum from Tavush region of Armenia were evaluated by DPPH assay with simultaneous monitoring of the total flavonoids content. Ուսումնասիրվել է ՀՀ Տավուշի մարզում աճող Hypericum perforatum-ի էքստրակտների հակաօքսիդիչ ակտիվությունը (DPPH) և ֆլավոնոիդների ընդհանուր պարունակության մոնիտորինգը: Исследован антиоксидантный потенциал экстрактов зверобоя продырявленного (Hypericum perforatum) из Тавушского марза Армении анализом антирадикальной (DPPH) активности с одновременным мониторингом общего содержания флавоноидов

Medical news of the North Caucasus

Prevention of dislocation of the hip in children with cerebral palsy: 20-year results of a popula... more Prevention of dislocation of the hip in children with cerebral palsy: 20-year results of a population-based prevention programme.

IFMBE Proceedings, 2019

The antibiotic resistance crisis is one of the most pressing public health issues worldwide. Nano... more The antibiotic resistance crisis is one of the most pressing public health issues worldwide. Nanoparticles (NPs) can offer a promising solution, since they have antibacterial properties, and can act as carriers for antibiotics and natural antimicrobial compounds. The purpose of this work was to study the antibacterial activity of silver nanoparticles, which are obtained by “green synthesis” from Ocimum araratum extract, against Staphylococcus aureus bacteria, as well as to study their combined action with antibiotic benzylpenicillin. The results show that the antibacterial effect of silver nanoparticles is higher than that of nanoparticles stabilized by the extract on the growth of S. aureus. It has been shown that benzylpenicillin can interact with the allosteric site of penicillin-binding protein 2a. It has also been shown that “green” AgNPs, which include phytocompounds of the extract of O. araratum can enhance the antibacterial effect of benzylpenicillin synergistically.

IFMBE Proceedings, 2019

The present study was conducted to evaluate the effect of artemisinins’ on the level of lipid per... more The present study was conducted to evaluate the effect of artemisinins’ on the level of lipid peroxidation (LPO), spontaneous chemiluminescence of the S-180 sarcoma homogenate and to study the nature of the interaction with canonical and non-canonical forms of DNA. Artemisinins are secondary metabolites of the medicinal plant Artemisia annua have anti-inflammatory, anticarcinogenic, immunomodulatory, antimicrobial, antihelminthic, antiviral, antioxidant and other properties. Our preliminary reverse virtual screening demonstrated that the ligand-binding domain of the human glucocorticoid receptor is the optimal target for artemisinin as well as for dexamethasone. However, the exact molecular targets and mechanisms of action of artemisinins are not well known. We have shown that the introduction of artemisinin leads to increase in LPO and chemiluminescence, which then causes apoptotic cell death in different ways without direct interaction with genomic DNA. We have also shown that art...

Biophotonics: Photonic Solutions for Better Health Care II, 2010

Biosensors are finding numerous applications in clinical diagnosis, drug discovery, biotechnology... more Biosensors are finding numerous applications in clinical diagnosis, drug discovery, biotechnology, environmental monitoring and etc. Hemoglobin (Hb), a natural heme containing protein, exhibits enzymatic activity towards hydrogen peroxide, which is possible to improve by altering the heme orientation and/or changing the microenvironment in the vicinity of the heme sites. It was shown that hypericin (HY), a naphthodianthrone from Hipericum perforatum

Enteropathogenic Escherichia coli remains one of the most important pathogens infecting children ... more Enteropathogenic Escherichia coli remains one of the most important pathogens infecting children as well as it causes persistent diarrhea worldwide. Bacteria communicate with each other through the quorum sensing system with the ability to respond to chemical molecules known as autoinducers. Quorum sensing in E. coli regulates the expression of virulence factors and biofilm formation. Suppressor of division inhibitor (SdiA) is a quorum sensing receptor present in \textit{E. coli}. Sdia is regulated by 1-octanoyl-rac-glycerol, which serves as an energy source, signaling molecule, and substrate for membrane biogenesis. Sdia can also detect acyl-homoserine lactone type autoinducers produced by other bacterial species. SdiA can be a potential target, but current crystallographic structures for virtual screening may not be sufficient for molecular docking, because the structures are in the active form. It has been shown that SdiA protein is not activated without a ligand, which binds to ...

Alzheimer’s disease is characterized by the formation of plaques in the brain, which are commonly... more Alzheimer’s disease is characterized by the formation of plaques in the brain, which are commonly composed of amyloid peptides as a result of aspartyl protease β-secretase expression. This work is dedicated to in silico studies of the interaction of artemisinin, dihydroartemisinin, dihydroartemisinin dimer with amyloid 12Aβ9–40 peptide and β-secretase. The comparison was made with curcumin, which is in phase II of clinical trials. It has been shown that all ligands, similarly to curcumin, bind to the specific amino acids of the peptide that are responsible for the formation and the growth of the fibril with high affinity. Moreover, dihydroartemisinin and dihydroartemisinin dimer bind to amino acids that are responsible for the stabilization of formed fibril. All studied ligands interact with the critical amino acids of the catalytic center of β- secretase, while dihydroartemisinin dimer can also bind to Arg235, which is characteristic of peptide inhibitors of β-secretase. Dihydroart...

In this work in silico study of the interaction of artemisinin with ligand bind domain of glucoco... more In this work in silico study of the interaction of artemisinin with ligand bind domain of glucocorticoid receptor by molecular modeling methods. Artemisinins belong to the family of sesquiterpene lactones, secondary metabolites of medicinal plant Artemisia annua, which has been traditionally used in Chinese medicine. Artemisinins exhibit antioxidant, anti-inflammatory, anticarcinogenic and other activities. Molecular docking, principal component analysis, cluster analysis have revealed three binding sites of artemisinin with ligand bind domain of glucocorticoid receptor which are very important regions. Comparative analysis was performed with dexamethasone, which is a corticosteroid medication. Thus, we have shown for the first time that artemisinin affects extremely important sites of ligand bind domain of glucocorticoid receptor, it should be noted that the first binding site of artemisinin corresponds to the interaction site of dexamethasone. This may represent a molecular basis ...

F1000Research

Background: In 2017, the World Health Organization announced a list of the most dangerous superbu... more Background: In 2017, the World Health Organization announced a list of the most dangerous superbugs. Among them is Pseudomonas aeruginosa, an opportunistic human pathogen with high levels of resistance to antibiotics that is listed as one of the ‘ESKAPE’ pathogens, which are the leading cause of nosocomial infections. A major issue is that it mostly affects vulnerable patients such as those suffering from AIDS, cystic fibrosis, cancer and severe burns. P. aeruginosa creates and inhabits surface-associated biofilms which increase resistance to antibiotics and host immune responses and contribute to the ineffectiveness of current antibacterial treatments. It is therefore imperative to find new antibacterial treatment strategies against P. aeruginosa. The LasR protein is a major transcriptional activator of P. aeruginosa and plays a pivotal role in biofilm formation and the activation of many virulence genes, although detailed characteristics of the LasR protein are not currently known...

Artemisinins are secondary metabolites of the medicinal plant Artemisia annua, which has been tra... more Artemisinins are secondary metabolites of the medicinal plant Artemisia annua, which has been traditionally used in Chinese medicine. Artemisinins have anti-inflammatory, anticarcinogenic, immunomodulatory, antimicrobial, anthelmintic, antiviral, antioxidant, and other properties. Our preliminary reverse virtual screening demonstrated that the ligand-binding domain of the human glucocorticoid receptor (LBD of hGR) is the optimal target for artemisinin. At the same time, the binding sites for artemisinin with the ligand-binding domain of the human glucocorticoid receptor coincide with those of dexamethasone. However, the pharmacokinetics, pharmacodynamics, and exact molecular targets and mechanisms of action of artemisinin are not well known. In this work, the interaction of artemisinin with human serum albumin (HSA) was studied both in vitro and in silico. The results indicate that artemisinin leads to a decrease in optical absorption and quenching of fluorescence by a static mechan...

Antibiotic resistance is a global problem nowadays and in 2017 the World Health Organization publ... more Antibiotic resistance is a global problem nowadays and in 2017 the World Health Organization published the list of bacteria for which treatment are urgently needed, where Pseudomonas aeruginosa is of critical priority. Current therapies lack efficacy because this organism creates biofilms conferring increased resistance to antibiotics and host immune responses. The strategy is to "not kill, but disarm" the pathogen and resistance will be developed slowly. It has been shown that LasI/LasR system is the main component of the quorum sensing system in P. aeruginosa. LasR is activated by the interaction with its native autoinducer. A lot flavones and their derivatives are used as antibacterial drug compounds. The purpose is to search compounds that will inhibit LasR. This leads to the inhibition of the synthesis of virulence factors thus the bacteria will be vulnerable and not virulent. We performed virtual screening using multiple docking programs for obtaining consensus predictions. The results of virtual screening suggest benzamides which are synthetical derivatives of flavones as potential inhibitors of transcriptional regulator LasR. These are consistent with recently published experimental data, which demonstrate the high antibacterial activity of benzamides. The compounds interact with the ligand binding domain of LasR with higher binding affinity than with DNA binding domain. Among the selected compounds, by conformational analysis, it was found that there are compounds that bind to the same amino acids of ligand binding domain as the native autoinducer. This could indicate the possibility of competitive interaction of these compounds. A number of compounds that bind to other conservative amino acids ligand binding domain have also been discovered, which will be of interest for further study. Selected compounds meet the criteria necessary for their consideration as drugs and can serve as a basis for conducting further in vitro / in vivo experiments. It could be used for the development of modern anti-infective therapy based on the quorum sensing system of P. aeruginosa.

ABSTRACTBackgroundPseudomonas aeruginosa is one of the most dangerous superbugs in the list of ba... more ABSTRACTBackgroundPseudomonas aeruginosa is one of the most dangerous superbugs in the list of bacteria for which new antibiotics are urgently needed, which was published by World Health Organization. P. aeruginosa is an antibiotic-resistant opportunistic human pathogen. It affects patients with AIDS, cystic fibrosis, cancer, burn victims and people with prosthetics and implants. P. aeruginosa also forms biofilms. Biofilms increase resistance to antibiotics and host immune responses. Because of biofilms, current therapies are not effective. It is important to find new antibacterial treatment strategies against P. aeruginosa. Biofilm formation is regulated through a system called quorum sensing. Thus disrupting this system is considered a promising strategy to combat bacterial pathogenicity. It is known that quercetin inhibits Pseudomonas aeruginosa biofilm formation, but the mechanism of action is unknown. In the present study, we tried to analyse the mode of interactions of LasR wi...

Nanomedicine, Feb 13, 2024

IFMBE proceedings, Sep 13, 2023

Cell Biochemistry and Biophysics

Физиология растений, 2016

Medical news of the North Caucasus

IFMBE Proceedings, 2019

Biophotonics: Photonic Solutions for Better Health Care II, 2010

F1000Research