Screening and Characterization of the Antagonistic Properties of Microorganisms Isolated From Natural Sources

BACKGROUND: Human infectious diseases caused by antibiotic-resistant bacterial pathogens present a serious problem for clinical medicine. Causative agents of nosocomial infections, such as Escherichia coli, Klebsiella pneumoniae, Enterobacter spp., are the most common among them. An active search for antimicrobial agents that can effectively combat drugresistant pathogens is underway. Antimicrobial substances of bacterial origin are of particular interest. Promising sources of microorganisms with antibiotic properties are natural sources: Soil, water, plants, etc. AIM: The purpose of this work is to screen and characterize the antagonistic properties of microorganisms isolated from natural sources in connection with the creation of new pharmaceutical substances. METHODS: The material for the isolation of microorganisms was the soil, water bodies, and plant objects of various municipal districts of the Kemerovo Region. Identification of the isolated microorganisms was carried out using the methods proposed in the directory “Bergey’s Manual of Determinative Bacteriology” and in the monograph Nesterenko et al. The selection of strains from soil samples was carried out according to standard methods described in “Methods of soil microbiological control. Methodical recommendations,” cultural-morphological properties of isolates were studied using conventional microbiological methods. RESULTS: The following results are obtained: (1) Lactic acid bacteria and other microorganisms antagonists from natural sources were isolated: Soil, water bodies, and plant objects; 20 isolates were isolated, their cultural and morphological properties were studied; isolated microorganisms were found to belong presumably to the genera Bacillus, Leuconostoc, Pedio-coccus, Lactobacillus, and Bacteroides; (2) Antimicrobial properties of lactic acid bacteria and other antagonistic microorganisms isolated from natural sources on solid and liquid nutrient media were studied; (3) 12 strains of 20 isolates with maximum antimicrobial properties were selected for further studies. CONCLUSION: Further research on the biochemical properties of lactic acid bacteria and other antagonist microorganisms isolated from natural sources, the study of antibiotic resistance of lactic acid bacteria and other antagonist microorganisms isolated from natural sources, as well as other more detailed studies will be conducted with selected 12 strains with maximum antimicrobial properties

In situ measurements of atmospheric O2 and CO2 reveal an unexpected O2 signal over the tropical Atlantic Ocean

We present the first meridional transects of atmospheric O2 and CO2 over the Atlantic Ocean. We combine these measurements into the tracer atmospheric potential oxygen (APO), which is a measure of the oceanic contribution to atmospheric O2 variations. Our new in situ measurement system, deployed on board a commercial container ship during 2015, performs as well as or better than existing similar measurement systems. The data show small short-term variability (hours to days), a step-change corresponding to the position of the Intertropical Convergence Zone (ITCZ), and seasonal cycles that vary with latitude. In contrast to data from the Pacific Ocean and to previous modeling studies, our Atlantic Ocean APO data show no significant bulge in the tropics. This difference cannot be accounted for by interannual variability in the position of the ITCZ or the Atlantic Meridional Mode Index and appears to be a persistent feature of the Atlantic Ocean system. Modeled APO using the TM3 atmospheric transport model does exhibit a significant bulge over the Atlantic and overestimates the interhemispheric gradient in APO over the Atlantic Ocean. These results indicate that either there are inaccuracies in the oceanic flux data products in the equatorial Atlantic Ocean region, or that there are atmospheric transport inaccuracies in the model, or a combination of both. Our shipboard O2 and CO2 measurements are ongoing and will reveal the long-term nature of equatorial APO outgassing over the Atlantic as more data become available

3D Silicon Photonic Structures Based on Avalanche LED with Interconnections through Optical Interposer

Design and manufacturing technology of 3-D silicon photonic structures with optical interconnections through microchannel vias interposers were developed. Silicon chips placed over each other were separated by the silicon microchannel vias interposer served as a light waveguide. Light emitting diodes and photodiodes were formed at the inner surfaces of silicon chips from nanostructured silicon clusters embedded into alumina matrix. The developed structure is characterized by the current conversion efficiency of 0.1 % and can operate in the GHz frequency range

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Measurement of a subpicosecond coherence time in a quasi-steady-state XUV laser

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Spectral Properties of Collisional Xuv Lasers for the Amplification of Femtosecond Pulses

International audienceWe discuss the role of the spectral properties of XUV lasers in the amplification of femtosecond pulses in two different regimes. We present an overview of our recent spectral characterization of the four types of collisionally-pumped systems, also including other measurements from the literature. This is used to assess the potential of the different types of XUV lasers to amplify femtosecond pulses, either in the adiabatic or in the dynamic regime

Spectral and Coherence Properties of the Ne-like Zn X-Ray Laser at PALS

International audienceWe present a refined measurement of the temporal coherence of the zinc X-ray laser generated at PALS, using a wavefront-division interferometer. The corresponding bandwidth of the lasing line is shown (i) to be broader than those of other types of X-ray lasers, previously characterized with the same instrument, and (ii) is compatible with the amplification of subpicosecond pulses. Similar measurements were also performed for shorter amplification lengths and the small-signal gain was carefully characterized

Overview of Development of Laser Driven Secondary Sources at PALS and ELI

International audienceIn this paper we report on development of the secondary X-ray sources at the PALS Centre and discuss the plan for the ELI Beamlines project. The spatial and temporal coherence of the most energetic quasi-steady state Ne-like Zn X-ray laser, which is operated at PALS Centre as standard user beamline, was examined proving that amplification of coherent EUV pulses with duration below 1 ps will be possible. Meanwhile, the first transient lasing at PALS Center was achieved using 10 Hz Ti: Sapphire laser chain with peak power of 20 TW as a driver. Finally, we discuss the recent design of laser driven secondary sources generating short coherent or incoherent EUV/X-ray pulses within the ELI Beamlines project