Astghik Zaven Pepoyan

Prof. Astghik Zaven Pepoyan

Armenian National Agrarian University, Yerevan, Armenia
+1
orcid

Research Focus & Metrics

Academic Career Length

29Years (1998-Present)

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

Representative Publications

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27 February 2023 in Microorganisms
Verified
Journal Article
Open access
PDF file
SMSusanna Mirzabekyan
Susanna Mirzabekyan
NHNatalya Aram Harutyunyan
Natalya Aram Harutyunyan
AMAnahit Manvelyan
Anahit Manvelyan
LMLilit Malkhasyan
Lilit Malkhasyan
MBMarine Balayan
Marine Balayan
APAstghik Zaven Pepoyan
Astghik Zaven Pepoyan
The properties of intestinal bacteria/probiotics, such as cell surface hydrophobicity (CSH), auto-aggregation, and biofilm formation ability, play an important role in shaping the relationship between the bacteria and the host. The current study aimed to investigate the cell surface properties of fish intestinal bacteria and probiotics. Microbial adhesion to hydrocarbons was tested according to Kos and coauthors. The aggregation abilities of the investigated strains were studied as described by Collado and coauthors. The ability of bacterial isolates to form a biofilm was determined by performing a qualitative analysis using crystal violet staining based on the attachment of bacteria to polystyrene. These studies prove that bacterial cell surface hydrophobicity (CSH) is associated with the growth medium, and the effect of the growth medium on CSH is species-specific and likely also strain-specific. Isolates of intestinal lactobacilli from fish (Salmo ischchan) differed from isolates of non-fish/shrimp origin in the relationship between auto-aggregation and biofilm formation. Average CSH levels for fish lactobacilli and E. coli might were lower compared to those of non-fish origin, which may affect the efficiency of non-fish probiotics use in fisheries due to the peculiarities of the hosts’ aquatic lifestyles.

26 September 2022 in Cells
Verified
Journal Article
Open access
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VTVardan Viktor Tsaturyan
Vardan Viktor Tsaturyan
APArmen Poghosyan
Armen Poghosyan
MTMichał Toczyłowski
Michał Toczyłowski
APAstghik Zaven Pepoyan
Astghik Zaven Pepoyan
Either extracts, cell-free suspensions or bacterial suspensions are used to study bacterial lipid peroxidation processes. Along with gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry, and several other strategies, the thiobarbituric acid test is used for the determination of malondialdehyde (MDA) as the basis for the commercial test kits and the colorimetric detection of lipid peroxidation. The aim of the current study was to evaluate lipid peroxidation processes levels in the suspensions, extracts and culture supernatants of Escherichia coli and Salmonella Derby strains. The dependence of the formation of thiobarbituric acid-reactive substances levels in the cell extracts, the suspensions and cell-free supernatants on bacterial species, and their concentration and growth phase were revealed. The effect of bacterial concentrations on MDA formation was also found to be more pronounced in bacterial suspensions than in extracts, probably due to the dynamics of MDA release into the intercellular space. This study highlights the possible importance of MDA determination in both cell-free suspensions and extracts, as well as in bacterial suspensions to elucidate the role of lipid peroxidation processes in bacterial physiology, bacteria–host interactions, as well as in host physiology.

18 May 2022 in Plants
Verified
Journal Article
Open access
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NHNatalya Aram Harutyunyan
Natalya Aram Harutyunyan
AKAlmagul Kushugulova
Almagul Kushugulova
NHNarine Hovhannisyan
Narine Hovhannisyan
APAstghik Zaven Pepoyan
Astghik Zaven Pepoyan
Tomato (Lycopersicon esculentum) is one of the most popular and valuable vegetables in the world. The most common products of its industrial processing in the food industry are juice, tomato paste, various sauces, canned or sun-dried fruits and powdered products. Tomato fruits are susceptible to bacterial diseases, and bacterial contamination can be a risk factor for the safety of processed tomato products. Developments in bioinformatics allow researchers to discuss target probiotic strains from an existing large number of probiotic strains for any link in the soil–plant–animal-human chain. Based on the literature and knowledge on the “One Health” concept, this study relates to the suggestion of a new term for probiotics: “One Health probiotics”, beneficial for the unity of people, animals, and the environment. Strains of Lactiplantibacillus plantarum, having an ability to ferment a broad spectrum of plant carbohydrates, probiotic effects in human, and animal health, as well as being found in dairy products, vegetables, sauerkraut, pickles, some cheeses, fermented sausages, fish products, and rhizospheric soil, might be suggested as one of the probable candidates for “One Health” probiotics (also, for “One Health—tomato” probiotics) for the utilization in agriculture, food processing, and healthcare.

26 June 2018 in Frontiers in Immunology
Verified
Journal Article
Open access
APAstghik Zaven Pepoyan
Astghik Zaven Pepoyan
MBMarine Balayan
Marine Balayan
AMAnahit Manvelyan
Anahit Manvelyan
LGLilit Galstyan
Lilit Galstyan
SPSofi Pepoyan
Sofi Pepoyan
MCMichael Chikindas
Michael Chikindas
Intestinal microorganisms play a crucial role in health and disease. The disruption of host –microbiota homeostasis has been reported to occur not only during disease development, but also as a result of medication. Familial Mediterranean fever (FMF) is an inflammatory genetic disease characterized by elevated systemic reactivity against the commensal gut microbiota and high levels of Candida albicans in the gut. This study’s major objective was to investigate the effects of commercial probiotic Narine on the relative abundance of gut bacteria (specifically, enterobacteria, lactobacilli, Staphylococcus aureus, and enterococci) of Candida albicans carrier and non-carrier FMF patients in remission. Our main finding indicates that the probiotic reduces numbers of C. albicans and abundance of enterobacteria in male and female patients of C. albicans carriers and non-carriers. It has pivotal effect on Enterococcus faecalis: increase in male non-carriers and decrease in female ones regardless of C. albicans status. No effect was seen for Lactobacillus and S. aureus. Our data suggest that M694V/V726A pyrin inflammasome mutations leading to FMF disease may contribute to gender specific differences in microbial community structure in FMF patients. The study’s secondary objective was to elucidate the gender-specific differences in the gut’s microbial community of FMF patients. The tendency was detected for higher counts of enterobacteria in female FMF subjects. However, the small number of patients of these groups preclude from conclusive statements, pointing at the need for additional investigations with appropriate for statistical analysis groups of subjects involved in the study.

2 February 2017 in Scientific Reports
Verified
Journal Article
Open access
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ZLZachery T Lewis
Zachery T Lewis
KSKetevan Sidamonidze
Ketevan Sidamonidze
VTVardan Viktor Tsaturyan
Vardan Viktor Tsaturyan
DTDavid Tsereteli
David Tsereteli
NKNika Khachidze
Nika Khachidze
DMDavid A Mills
David A Mills
Multiple factors help shape the infant intestinal microbiota early in life. Environmental conditions such as the presence of bioactive molecules from breast milk dictate gut microbial growth and survival. Infants also receive distinct, personalized, bacterial exposures leading to differential colonization. Microbial exposures and gut environmental conditions differ between infants in different locations, as does the typical microbial community structure in an infant’s gut. Here we evaluate potential influences on the infant gut microbiota through a longitudinal study on cohorts of breast-fed infants from the neighboring countries of Armenia and Georgia, an area of the world for which the infant microbiome has not been previously investigated. Marker gene sequencing of 16S ribosomal genes revealed that the gut microbial communities of infants from these countries were dominated by bifidobacteria, were different from each other, and were marginally influenced by their mother’s secretor status. Species-level differences in the bifidobacterial communities of each country and birth method were also observed. These community differences suggest that environmental variation between individuals in different locations may influence the gut microbiota of infants.

27 May 2020 in Probiotics and Antimicrobial Proteins
Verified
Journal Article
Closed access
PDF file
APAstghik Zaven Pepoyan
Astghik Zaven Pepoyan
AMAnahit M. Manvelyan
Anahit M. Manvelyan
MBMarine H. Balayan
Marine H. Balayan
GMGavin McCabe
Gavin McCabe
VTVardan Viktor Tsaturyan
Vardan Viktor Tsaturyan
Andrey V. KarlyshevAndrey V. Karlyshev
Andrey V. Karlyshev