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Игнатов, О. В.; Gribanova, Yu. S.; Shchegolev, S. Yu.; Bunin, Victor D.; Игнатов, В. В.

doi:10.1023/a:1015854611552

Cited by 14 publications

(15 citation statements)

References 9 publications

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“…Others have shown a relationship between intracellular Na ϩ -to-K ϩ cationic ratios (69) and pH of the medium, age of the culture, and cell metabolism (70,71). Since the Na ϩ -to-K ϩ ratios affect the cellular proton motive force (PMF), we investigated how the membrane potential varied under stressful growth conditions (e.g., low pH and osmotic stress).…”

Section: Discussionmentioning

confidence: 99%

Trk2 Potassium Transport System in Streptococcus mutans and Its Role in Potassium Homeostasis, Biofilm Formation, and Stress Tolerance

et al. 2016

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Potassium (K؉ ) is the most abundant cation in the fluids of dental biofilm. The biochemical and biophysical functions of K ؉ and a variety of K ؉ transport systems have been studied for most pathogenic bacteria but not for oral pathogens. In this study, we establish the modes of K ؉ acquisition in Streptococcus mutans and the importance of K ؉ homeostasis for its virulence attributes. The S. mutans genome harbors four putative K ؉ transport systems that included two Trk-like transporters (designated Trk1 and Trk2), one glutamate/K ؉ cotransporter (GlnQHMP), and a channel-like K ؉ transport system (Kch). Mutants lacking Trk2 had significantly impaired growth, acidogenicity, aciduricity, and biofilm formation. [K ؉ ] less than 5 mM eliminated biofilm formation in S. mutans. The functionality of the Trk2 system was confirmed by complementing an Escherichia coli TK2420 mutant strain, which resulted in significant K ؉ accumulation, improved growth, and survival under stress. Taken together, these results suggest that Trk2 is the main facet of the K ؉ -dependent cellular response of S. mutans to environment stresses. IMPORTANCEBiofilm formation and stress tolerance are important virulence properties of caries-causing Streptococcus mutans. To limit these properties of this bacterium, it is imperative to understand its survival mechanisms. Potassium is the most abundant cation in dental plaque, the natural environment of S. mutans. K ؉ is known to function in stress tolerance, and bacteria have specialized mechanisms for its uptake. However, there are no reports to identify or characterize specific K ؉ transporters in S. mutans. We identified the most important system for K ؉ homeostasis and its role in the biofilm formation, stress tolerance, and growth. We also show the requirement of environmental K ؉ for the activity of biofilm-forming enzymes, which explains why such high levels of K ؉ would favor biofilm formation. Bacteria utilize specialized endogenous mechanisms to survive and proliferate in transient environments. A common bacterial response to environmental perturbations, such as acid stress, osmotic tension, and nutrient deprivation, is to accumulate certain solutes, such as potassium (K ϩ ). K ϩ , a naturally abundant cation, is present in all types of cells and is essential for both cell survival and physiology. K ϩ accumulation under stress conditions enables organisms to contend with dehydration, membrane damage, regulation of the Na ϩ /H ϩ -dependent cell energetics, and pH homeostasis while simultaneously minimizing interference with the structures and functions of intracellular proteins (1-3).In prokaryotes, four main K ϩ transport systems have been identified, which include the proteins Trk (or Ktr), Kdp, Kup, and channel-like Kch (4), all of which have different K ϩ affinities. Their variety and independent functioning have likely evolved as a cell survival strategy to ensure that adequate levels of K ϩ are present at all times to contend with environmental changes (5). These systems are r...

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Section: Discussionmentioning

confidence: 99%

Trk2 Potassium Transport System in Streptococcus mutans and Its Role in Potassium Homeostasis, Biofilm Formation, and Stress Tolerance

et al. 2016

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“…This is of potential interest for emitters and detectors of high-frequency ͑GHz-THz͒ radiation. 17,18 Our study is also of general interest as it concerns the electron dynamics in an unusual material system, which could find interesting applications in other high-field devices such as quantum cascade lasers. 19 …”

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confidence: 99%

Hot-electrons and negative differential conductance inGaAs1−xNx

et al. 2005

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We show that the manipulation of the band structure of GaAs by the incorporation of a small amount of N provides a powerful means of tailoring the dynamics of conduction electrons. We observe and model theoretically a strong negative differential velocity ͑NDV͒ effect that occurs when electrons are accelerated by an electric field in the highly nonparabolic conduction band of Ga͑AsN͒. The NDV effect is fundamentally different from that occurring in superlattice Bloch oscillators and transferred electron devices, and is of potential interest for emitters and detectors of high-frequency radiation.

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“…10 3 Hz is created by electrochemical processes in the organism and is modulated by the rhythm of internal organs [19]. The spatial distribution of the electric field around the body reflects the teamwork of the different organs and systems in the organism.…”

Section: Electric Fieldsmentioning

confidence: 99%

“…The most interesting biological phenomenon is the ability of some microorganisms to grow on D2O media in which all hydrogen atoms are replaced with deuterium [1,2]. The average ratio of H/D in nature makes up approximately 1:5700 [3].…”

Section: Introductionmentioning

confidence: 99%

Methods For Registering Non-Ionizing Radiation Emitted From The Human Body

Ignatov¹,

Mosin²,

Niggli³

et al. 2015

European Reviews of Chemical Research

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This paper presents the results of evaluation of possible biophysical methods and approaches for registering of various non-ionizing radiation (NIR) wave types of the human body in the optic and electromagnetic range. Various types of NIR (electromagnetic waves, infrared radiation, thermo radiation, bioluminiscence) emitted from the human body were reviewed. In particular the results on of spontaneous biophoton emission and delayed luminescence from the human body are submitted along with infrared thermography (IRT) results. It was shown that 1 cm 2 of skin generally emits 85 photons for 1 s. The intensity of biophoton emission ranges from 10 −19 to 10 −16 W/cm 2 (approx. 1-1000 photons . cm -2. s -1 ). The specific photon emission from part of the human thumb was detected as a spectrum of various colours with the method of Colour coronal spectral analysis on a device with an electrode made of polyethylene terephthalate (PET hostaphan) with applied electric voltage 15 kV, electric impulse duration 10 s, and electric current frequency 15 kHz. It was established that photons corresponding to a red color emission of visible electromagnetic spectrum have energy at 1,82 еV. The orange color of visible electromagnetic spectrum has energy at 2,05 eV, yellow -2,14 eV, blue-green (cyan) -2,43 eV, blue -2,64 eV, and European Reviews of Chemical Research, 2015, Vol.(3), Is. 1 5 violet -3,03 eV. The reliable result measurement norm was at E ≥ 2,53 eV, while the spectral range of the emission was within  = 380-495±5 nm and  = 570-750±5 nm. Also were estimated some important physical characteristics (energy of hydrogen bonds, wetting angle, surface tension) of water by the methods of non-equilibrium energy (NES) and differential non-equilibrium energy (DNES) spectrum of water, that helps understand in general how electromagnetic radiation interacts with water and establish the structural characteristics of water.

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Cited by 14 publications

References 9 publications

Trk2 Potassium Transport System in Streptococcus mutans and Its Role in Potassium Homeostasis, Biofilm Formation, and Stress Tolerance

Trk2 Potassium Transport System in Streptococcus mutans and Its Role in Potassium Homeostasis, Biofilm Formation, and Stress Tolerance

Hot-electrons and negative differential conductance inGaAs1−xNx

Methods For Registering Non-Ionizing Radiation Emitted From The Human Body

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