The Effects of Low Doses of Gamma-Radiation on Growth and Membrane Activity of Pseudomonas aeruginosa GRP3 and Escherichia coli M17

Microorganisms are part of the natural environments and reflect the effects of different physical factors of surrounding environment, such as gamma (γ) radiation. This work was devoted to the study of the influence of low doses of γ radiation with the intensity of 2.56 μW (m² s)^-1 (absorbed doses were 3.8 mGy for the radiation of 15 min and 7.2 mGy-for 30 min) on Escherichia coli M-17 and Pseudomonas aeruginosa GRP3 wild type cells. The changes of bacterial, growth, survival, morphology, and membrane activity had been studied after γ irradiation. Verified microbiological (specific growth rate, lag phase duration, colony-forming units (CFU) number, and light microscopy digital image analysis), biochemical (ATPase activity of bacterial membrane vesicles), and biophysical (H⁺ fluxes throughout cytoplasmic membrane of bacteria) methods were used for assessment of radiation implications on bacteria. It was shown that growth specific rate, lag phase duration and CFU number of these bacteria were lowered after irradiation, and average cell surface area was decreased too. Moreover ion fluxes of bacteria were changed: for P. aeruginosa they were decreased and for E. coli-increased. The N,N'-dicyclohexylcarbodiimide (DCCD) sensitive fluxes were also changed which were indicative for the membrane-associated F₀F₁-ATPase enzyme. ATPase activity of irradiated membrane vesicles was decreased for P. aeruginosa and stimulated for E. coli. Furthermore, DCCD sensitive ATPase activity was also changed. The results obtained suggest that these bacteria especially, P. aeruginosa are sensitive to γ radiation and might be used for developing new monitoring methods for estimating environmental changes after γ irradiation.

Assessment of patrilineal gene pool of the Iranian Azeris

The Iranian Azeris are the largest ethno-linguistic minority in Iran who live mainly in the north-west part of the country. Located in the crossroad of ancient human migrations the Iranian Azeris bear the complicated historical influence of the region in their gene pool. Despite the importance of Iranian Azeris in reconstructing the historical event of the Middle-East, their (genetic) origin still remains heavily disputed. In this study we tried to evaluate the rates of genetic contribution of possible source populations (namely, indigenous Iranian, Caucasian, and Central Asian) in the gene pool of modern Iranian Azeris through paternally inherited Y-chromosomal 6 STR markers. The assessment of genetic distances reveals that the Iranian Azeris are mixed population with substantial North Caucasian genetic contribution being genetically much closer to their immediate neighboring ethnic groups. Based on the results of admixture analysis we can conclude that there are significant Caucasian and no visible Central Asian contribution to the gene pool of modern Iranian Azeris.

Observation of the (Λ)(7)He hypernucleus by the (e, e'K+) reaction

An experiment with a newly developed high-resolution kaon spectrometer and a scattered electron spectrometer with a novel configuration was performed in Hall C at Jefferson Lab. The ground state of a neutron-rich hypernucleus, (Λ)(7)He, was observed for the first time with the (e, e'K+) reaction with an energy resolution of ~0.6 MeV. This resolution is the best reported to date for hypernuclear reaction spectroscopy. The (Λ)(7)He binding energy supplies the last missing information of the A = 7, T = 1 hypernuclear isotriplet, providing a new input for the charge symmetry breaking effect of the ΛN potential.

Iranian Azeri's Y-Chromosomal Diversity in the Context of Turkish-Speaking Populations of the Middle East

BACKGROUND

The main goal of this study was to conduct a comparative population genetic study of Turkish speaking Iranian Azeries as being the biggest ethno-linguistic community, based on the polymorph markers on Y chromosome.

METHODS

One hundred Turkish-speaking Azeri males from north-west Iran (Tabriz, 2008-2009) were selected based on living 3 generations paternally in the same region and not having any relationship with each other. Samples were collected by mouth swabs, DNA extracted and multiplex PCR done, then 12 Single Nucleotide Polymorphisms (SNPs) and 6 Microsatellites (MS) were sequenced. Obtained data were statistically analyzed by Arlequin software.

RESULTS

SNPs and Microsatellites typing were compared with neighboring Turkish-speaking populations (from Turkey and Azerbaijan) and Turkmens representing a possible source group who imposed the Turkish language during 11-15(th) centuries AD. Azeris demonstrated high level of gene diversity compatible with patterns registered in the neighboring Turkish-speaking populations, whereas the Turkmens displayed significantly lower level of genetic variation. This rate of genetic affiliation depends primarily on the geographic proximity.

CONCLUSION

The imposition of Turkish language to this region was realized predominantly by the process of elite dominance, i.e. by the limited number of invaders who left only weak patrilineal genetic trace in modern populations of the region.

High resolution spectroscopy of the 12Lambda B hypernucleus produced by the (e,e'K+) reaction

High-energy, cw electron beams at new accelerator facilities allow electromagnetic production and precision study of hypernuclear structure, and we report here on the first experiment demonstrating the potential of the (e,e'K+) reaction for hypernuclear spectroscopy. This experiment is also the first to take advantage of the enhanced virtual photon flux available when electrons are scattered at approximately zero degrees. The observed energy resolution was found to be approximately 900 keV for the (12)(Lambda)B spectrum, and is substantially better than any previous hypernuclear experiment using magnetic spectrometers. The positions of the major excitations are found to be in agreement with a theoretical prediction and with a previous binding energy measurement, but additional structure is also observed in the core excited region, underlining the future promise of this technique.

Cohort studies of chloroprene-exposed workers in Russia

Two retrospective cohort studies were conducted to assess the risk of cancer among workers exposed to chloroprene (2-chloro-1,3-butadiene) (CP). One is a study of incidence and mortality among 2314 production workers employed in the CP production plant in Yerevan, Armenia, between 1940 and 1988. The cohort was followed up for cancer incidence for the years 1979-1990 and for cancer mortality for 1979-1988. The second study is a mortality study among 5185 shoe manufacturing workers in Moscow who used polychloroprene latex and glue. Shoe workers were employed between 1940 and 1976, and followed from 1979 through 1993. The standardized incidence ratios (SIR) and standardized mortality ratios (SMR) were calculated using the Armenian and Moscow population as reference. An internal comparison analysis based on Poisson regression modeling was conducted. In the Yerenan cohort, incidence and mortality from all cancers were below expectation, but increased incidence (SIR, 3.27; 95% confidence interval (CI), 1.47-7.27), and mortality (SMR, 3.39; CI, 1.09-10.5) from liver cancer were noted. A dose-response relationship was suggested between the risk of liver cancer and indices of CP exposure. For the entire Moscow cohort, all-cause mortality was close to expectation and all-cancer mortality was increased. There was an increase in the mortality from liver cancer (SMR, 2.4; CI, 1.1-4.3), kidney cancer (SMR, 1.8; CI, 0.9-3.4), and leukemia (SMR, 1.9; CI, 1.0-3.3). Mortality from liver cancer and leukemia was associated with various indicators of CP exposure. A similar, although less consistent, pattern was found for kidney cancer. The association between CP exposure and risk of leukemia may be due to concomitant exposure to benzene. The results for liver cancer point towards a carcinogenic effect of CP.