Life science International Postgraduate Educational Center

Yerevan, Armenia

Life science International Postgraduate Educational Center

Yerevan, Armenia

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Martirosyan V.,Bar - Ilan University | Martirosyan V.,Life science International Postgraduate Educational Center | Unc A.,Memorial University of Newfoundland | Miller G.,Bar - Ilan University | And 3 more authors.
Microbial Ecology | Year: 2016

Microbial function, composition, and distribution play a fundamental role in ecosystem ecology. The interaction between desert plants and their associated microbes is expected to greatly affect their response to changes in this harsh environment. Using comparative analyses, we studied the impact of three desert shrubs, Atriplex halimus (A), Artemisia herba-alba (AHA), and Hammada scoparia (HS), on soil- and leaf-associated microbial communities. DNA extracted from the leaf surface and soil samples collected beneath the shrubs were used to study associated microbial diversity using a sequencing survey of variable regions of bacterial 16S rRNA and fungal ribosomal internal transcribed spacer (ITS1). We found that the composition of bacterial and fungal orders is plant-type-specific, indicating that each plant type provides a suitable and unique microenvironment. The different adaptive ecophysiological properties of the three plant species and the differential effect on their associated microbial composition point to the role of adaptation in the shaping of microbial diversity. Overall, our findings suggest a link between plant ecophysiological adaptation as a “temporary host” and the biotic-community parameters in extreme xeric environments. © 2016 Springer Science+Business Media New York


Martirosyan V.,Bar - Ilan University | Martirosyan V.,Life science International Postgraduate Educational Center | Steinberger Y.,Bar - Ilan University
Journal of Arid Environments | Year: 2014

Our aim was to determine the effect of plant ecophysiological adaptations on below-canopy (laimosphere or soil) and above-canopy (phyllosphere or leaf surface) microbial functional diversity and investigate potential correlations between biotic and abiotic factors in laimospheres and phyllospheres of three different desert halophyte shrubs with different ecophysiological adaptations: Atriplex halimus, Artemisa herba-alba, and Hammada scoparia. Soil and leaf samples were collected at two habitats from each shrub at the end of the dry season, while an interplant open area was used as control. Soil and leaf biotic and abiotic analyses were performed. The results demonstrated the importance of plant ecophysiological adaptations, which play an important role as abiotic environmental mediators and microbial-community 'temporary hosts', determining microbial biomass, CO2 evolution, functional diversity, and population size. Although the shrubs were observed as having a major effect on microbial functional diversity, more detailed study is needed that will use modern molecular-biology tools to investigate potential correlations between biotic and abiotic factors in order to evaluate their impact on microbial-species composition on a temporal/spatial basis. This will contribute to better understanding of the link between plant ecophysiological adaptation as a 'temporary host' and the biotic-community parameters in extreme xeric environments. © 2014 Elsevier Ltd.


Martirosyan V.,Life science International Postgraduate Educational Center
Journal of Low Frequency Noise Vibration and Active Control | Year: 2012

In the present work there have been studied the frequency-dependent effects of mechanical vibration (MV) and extremely low frequency electromagnetic field (ELF EMF) on bacterial cell proliferation. It was suggested that the aqua medium can serve as a target through which the biological effect of MV and ELF EMF on microbes could be realized. To check this hypothesis the frequency-dependent effect (2, 4, 6, 8, 10 Hz) of both MV (8 mm displacement) and EMF (0.4 mT intensity) on the bacterial cell proliferation were studied in both cases where the microbes were in the culture media during the exposure and when culture media was preliminarily exposed to the ELF EMF and MV prior to the addition of bacteria. For investigating the cell proliferation a tritiated thymidine ([3H]dT) assay was used. This study demonstrated that 4 and 8 Hz EMF and MV have different biological effects on bacterial cell proliferation.


Ayrapetyan S.,Life science International Postgraduate Educational Center
Electromagnetic Biology and Medicine | Year: 2015

The weak knowledge on the nature of cellular and molecular mechanisms of biological effects of NIR such as static magnetic field, infrasound frequency of mechanical vibration, extremely low frequency of electromagnetic fields and microwave serves as a main barrier for adequate dosimetry from the point of Public Health. The difficulty lies in the fact that the biological effects of NIR depend not only on their thermodynamic characteristics but also on their frequency and intensity "windows", chemical and physical composition of the surrounding medium, as well as on the initial metabolic state of the organism. Therefore, only biomarker can be used for adequate estimation of biological effect of NIR on organisms. Because of the absence of such biomarker(s), organizations having the mission to monitor hazardous effects of NIR traditionally base their instruction on thermodynamic characteristics of NIR. Based on the high sensitivity to NIR of both aqua medium structure and cell hydration, it is suggested that cell bathing medium is one of the primary targets and cell hydration is a biomarker for NIR effects on cells and organisms. The purpose of this article is to present a short review of literature and our own experimental data on the effects of NIR on plants seeds germination, microbe growth and development, snail neurons and heart muscle, rats brain and heart tissues. © 2015 Taylor & Francis.


Martirosyan V.,Life science International Postgraduate Educational Center | Ayrapetyan S.,Life science International Postgraduate Educational Center
Electromagnetic Biology and Medicine | Year: 2015

The aim of the present work is to study the time-dependent effects of mechanical vibration (MV) at infrasound (IS) frequency at 4 and 8 Hz on E. Coli K-12 growth by investigating the cell proliferation, using radioactive [3H]-thymidine assay. In our previous work it was suggested that the aqua medium can serve as a target through which the biological effect of MV on microbes could be realized. At the same time it was shown that microbes have mechanosensors on the surface of the cells and can sense small changes of the external environment. The obtained results were shown that the time-dependent effects of MV at 4 and 8 Hz frequency could either stimulate or inhibit the growth of microbes depending from exposure time. It more particularly, the invention relates to a method for controlling biological functions through the application of mechanical vibration, thus making it possible to artificially control the functions of bacterial cells, which will allow us to develop method that can be used in agriculture, industry, medicine, biotechnology to control microbial growth. © 2014 © 2014 Taylor & Francis.


Baghdasaryan N.,Life science International Postgraduate Educational Center | Mikayelyan Y.,Life science International Postgraduate Educational Center | Barseghyan S.,Life science International Postgraduate Educational Center | Dadasyan E.,Life science International Postgraduate Educational Center | Ayrapetyan S.,Life science International Postgraduate Educational Center
Electromagnetic Biology and Medicine | Year: 2012

The effects of dark -(Ev = 0 lux) and low-background radiation (BGR), where R < 1μRongen/h, on physicochemical properties (specific electrical conductivity, heat fusion, hydrogen peroxide (H 2O 2), and oxygen contents) of distilled water (DW) and physiological solution (PS) at 4°C and 18°C were studied. The incubation of DW and PS samples in dark and in low BGR (under dark) medium at 4°C and 18°C brings to changes of their physicochemical properties compared with DW and PS samples incubated in light and normal BGR condition (Ev = 500-550 lux and R = 17 μRoentgen/h). The observed changes of DW and PS properties depended on their initial temperature, density and ionic composition. It is suggested that water molecules dissociation and ions hydration are sensitive to illumination and BGR. Therefore, the cell-bathing medium can be considered as a messenger through which direct and non direct (by modulating of others factors-induced effects) influences of illumination and BGR on cell metabolism are realized. © Informa Healthcare USA, Inc.


Martirosyan V.,Life science International Postgraduate Educational Center | Baghdasaryan N.,Life science International Postgraduate Educational Center | Ayrapetyan S.,Life science International Postgraduate Educational Center
Electromagnetic Biology and Medicine | Year: 2013

The aim of the present work was to investigate the frequency-dependent effects of mechanical vibration at infrasound frequency (MV at IS frequency or MV) on E. coli K-12 growth by investigating the cell proliferation, using radioactive [3H]-thymidine assay. The frequency-dependent effects of MV were shown that it could either stimulate or inhibit the growth of microbes. However, the mechanism through which the MV effects affect the bacterial cells is not clear yet. It was suggested that the aqua medium can serve as a target through which the biological effect of MV on microbes could be realized. To check this hypothesis the frequency-dependent effect (2, 4, 6, 8, 10 Hz) of MV on the bacterial growth in cases of exposure the preliminary treated microbes-free medium and microbes containing medium were studied. It has been shown that MV at 4, 8, and 10 Hz frequency has inhibition effects, while at 2 and 6 Hz has stimulation effects on cell proliferation. © Informa Healthcare USA, Inc.


Naira B.,Life Science International Postgraduate Educational Center | Yerazik M.,Life Science International Postgraduate Educational Center | Anna N.,Life Science International Postgraduate Educational Center | Sinerik A.,Life Science International Postgraduate Educational Center
Electromagnetic Biology and Medicine | Year: 2013

The effects of extremely low frequency electromagnetic field (ELF EMF) on physicochemical properties of physiological solution at different environmental media were studied. The existence of frequency "windows" at 4 and 8 Hz frequencies of ELF EMF having effects on heat fusion period, hydrogen peroxide (H2O2) formation and oxygen (O2) content of water solution and different dependency on temperature, background radiation and illumination was shown. Obtained data allow us to suggest that EMF-induced effect on water physicochemical properties depends on abovementioned environmental factors. As cell bathing medium is a target for biological effects of ELF EMF, the variability of experimental data on biological effects of EMF, obtained in different laboratories, can be explained by different environmental conditions of experiments, which very often are not considered adequately. © Informa UK Ltd.


Martirosyan V.,Life science International Postgraduate Educational Center | Baghdasaryan N.,Life science International Postgraduate Educational Center | Ayrapetyan S.,Life science International Postgraduate Educational Center
Electromagnetic Biology and Medicine | Year: 2013

In the present work, the frequency-dependent effects of extremely low-frequency electromagnetic field (ELF EMF) on Escherichia coli K-12 growth have been studied. The frequency-dependent effects of ELF EMF have shown that it can either stimulate or inhibit the growth of microbes. However, the mechanism by which the ELF EMF affects the bacterial cells is not clear yet. It was suggested that the aqua medium can serve as a target through which the biological effect of ELF EMF on microbes may be realized. To check this hypothesis, the frequency-dependent effects (2, 4, 6, 8, 10 Hz, B = 0.4 mT, 30 min) of ELF EMF on the bacterial growth were studied in both cases where the microbes were in the culture media during the exposure and where culture media was preliminarily exposed to the ELF EMF before the addition of bacteria. For investigating the cell proliferation, the radioactive [3H]-thymidine assay was carried out. It has been shown that EMF at 4 Hz exposure has pronounced stimulation while at 8 Hz it has inhibited cell proliferation. © Informa UK Ltd.


PubMed | Life science International Postgraduate Educational Center
Type: Journal Article | Journal: Electromagnetic biology and medicine | Year: 2013

In the present work, the frequency-dependent effects of extremely low-frequency electromagnetic field (ELF EMF) on Escherichia coli K-12 growth have been studied. The frequency-dependent effects of ELF EMF have shown that it can either stimulate or inhibit the growth of microbes. However, the mechanism by which the ELF EMF affects the bacterial cells is not clear yet. It was suggested that the aqua medium can serve as a target through which the biological effect of ELF EMF on microbes may be realized. To check this hypothesis, the frequency-dependent effects (2, 4, 6, 8, 10Hz, B=0.4mT, 30min) of ELF EMF on the bacterial growth were studied in both cases where the microbes were in the culture media during the exposure and where culture media was preliminarily exposed to the ELF EMF before the addition of bacteria. For investigating the cell proliferation, the radioactive [(3)H]-thymidine assay was carried out. It has been shown that EMF at 4Hz exposure has pronounced stimulation while at 8Hz it has inhibited cell proliferation.

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