HMG-CoA reductase is regulated by environmental salinity and its activity is essential for halotolerance in halophilic fungi

The activity and level of HMG-CoA reductase (HMGR) were addressed in halophilic fungi isolated from solar saltpans. Representative fungi belonging to the orders Dothideales, Eurotiales and Wallemiales have a specific pattern of HMGR regulation, which differs from salt-sensitive and moderately salt-tolerant yeasts. In all of the halophilic fungi studied, HMGR amounts and activities were the lowest at optimal growth salinity and increased under hyposaline and hypersaline conditions. This profile paralleled isoprenylation of cellular proteins in H. werneckii. Inhibition of HMGR in vivo by lovastatin impaired the halotolerant character. HMGR may thus serve as an important molecular marker of halotolerance

Expression of fatty-acid-modifying enzymes in the halotolerant black yeast Aureobasidium pullulans (de Bary) G. Arnaud under salt stress

AbstractMultiple tolerance to stressful environmental conditions of the black, yeast-like fungus Aureobasidium pullulans is achieved through different adaptations, among which there is the restructuring of the lipid composition of their membranes. Here, we describe three novel genes encoding fatty-acid-modifying enzymes in A. pullulans, along with the levels of their mRNAs under different salinity conditions. High levels of Δ 9−desaturase and Δ12−desaturase mRNAs were seen at high salinities, which were consistent with an increased desaturation of the fatty acids in the cell membranes. Elevated levels of elongase mRNA were also detected. Surprisingly, increases in the levels of these mRNAs were also seen following hypo-osmotic shock, while hyperosmotic shock had exactly the opposite effect, demonstrating that data that are obtained from up-shift and down-shift salinity studies should be interpreted with caution

Critical behavior of the optical birefringence at the nematic to twist bend nematic phase transition

This research was supported by the National Science Centre (Poland) under the grant no. 2016/22/A/ST5/00319. NV acknowledges the support of the Slovenian Research Agency (ARRS), through the research programme P1-0055.Peer reviewedPublisher PD

Multi-level chirality in liquid crystals formed by achiral molecules

M.S., D.P., and N.V. acknowledge the support of the National Science Centre (Poland) under the grant no. 2016/22/A/ST5/00319. E.G. acknowledges the funding from the Foundation for Polish Science through the Sabbatical Fellowships Program. N.V. acknowledges the support of the Slovenian Research Agency (ARRS), through the research core funding no. P1-0055. R.W. gratefully acknowledges the Carnegie Trust for the Universities of Scotland for funding the award of a PhD scholarship. The beamline 11.0.1.2 at the Advanced Light Source at the Lawrence Berkeley National Laboratory is supported by the director of the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.Peer reviewedPublisher PD

Adaptation of extremely halotolerant black yeast Hortaea werneckii to increased osmolarity: a molecular perspective at a glance

Halophilic adaptations have been studied almost exclusively on prokaryotic microorganisms. Discovery of the black yeast Hortaea werneckii as the dominant fungal species in hypersaline waters enabled the introduction of a new model organism to study the mechanisms of salt tolerance in eukaryotes. Its strategies of cellular osmotic adaptations on the physiological and molecular level revealed novel, intricate mechanisms to combat fluctuating salinity. H. werneckii is an extremely halotolerant eukaryotic microorganism and thus a promising source of transgenes for osmotolerance improvement of industrially important yeasts, as well as in crops

Diurnal variations of radon and thoron activity concentrations and effective doses in dwellings in Niska Banja, Serbia

In NiUka Banja, a spa town in a radon-prone area in southern Serbia, radon (Rn-222) and thoron (Rn-220) activity concentrations were measured continuously for one day in indoor air of 10 dwellings with a SARAD RTM 2010-2 Radon/Thoron Monitor, and equilibrium factor between radon and its decay products and the fraction of unattached radon decay products with a SARAD EQF 3020-2 Equilibrium Factor Monitor. Radon concentration in winter time ranged from 26 to 73 100 Bq m(3) and that of thoron, from 10 to 8650 Bq m(3). In the same period, equilibrium factor and the unattached fraction varied in the range of 0.08 to 0.90 and 0.01 to 0.27, respectively. One-day effective doses were calculated and were in winter conditions from 4 to 2599 Sv d(1) for radon and from 0.2 to 73 Sv d(1) for thoron

Concentrations of Rn-222 and Rn-220 in indoor air

Radon (Rn-222) and thoron (Rn-220) were surveyed in indoor air of 15 public buildings and 10 homes in Slovenia in November 2004 by exposing Rn-Tn discriminative etched track detectors. The following ranges of the activity concentration were obtained for public buildings: 98-2680 Bq m(-3) for C-Rn, 19-1330 Bq m(-3) for C-Tn and 0.11-0.72 for the C-Tn/C-Rn ratio. In homes, the C-Rn range was 12-374 Bq m(-3) and all C-Tn values, except one of 29 Bq m(-3), were below the detection limit of 10 Bq m-3. Monthly effective doses in public buildings due to Rn (E-Rn) and Tn (E-Tn) were in the ranges 0.05-1.45 mSv and 0.01-0.47 mSv, respectively, and in homes, 0.018-0.548 and 0.009-0.095 mSv, respectively. The E-Tn/E-Rn ratio in public buildings was in the range 0.07-0.47