Lucia Dumitru

Halophilic archaea isolated from man-made young (200 years) salt lakes in Slănic, Prahova, Romania

We isolated a number of extremely halophilic archaea from four salt lakes (Red Bath, Green Bath, Shepherd Bath and Bride Cave) located in Slanic Prahova, Romania. The characterization of 12 representative isolates by polyphasic approach revealed that 11 strains were members of the genus Haloferax and only one was a member of the genus Haloarcula. The 11 Haloferax isolates possessed sulfated diglycosylarchaeol-1 as the major membrane glycolipid, and G+C contents of total DNA were 63.4–65.8 mol%. The predominant isolation of Haloferax species from the lakes may suggest that the underground salt deposit possesses Haloferax species as the major biota of ancient origin. To the best of the authors’ knowledge, this is the first paper on the survey of halophilic archaea of man-made young salt lakes.

Halophilic bacteria are able to decontaminate dichlorvos, a pesticide, from saline environments

Dichlorvos (DDVP) is an organophosphorous pesticide with a high degree of dangerous effect towards the environment. We have investigated the growth and susceptibility to DDVP of halophilic bacteria isolated from Romanian salt lakes. The growth of four strains was affected by DDVP, which may be correlated with the rate constant values of DDVP disappearance from the saline solutions. This is due not to a chemical degradation in solution but to the diffusion process and namely DDVP penetration into the cell cytoplasm by an “organic-osmolyte” mechanism. The permeability coefficient P was calculated.

Silver/Porous Silicon (PS) Nanocomposite Layers for Biomedical Applications

The as-deposited and thermal treated Ag nanoparticles/silicon nanocomposite layers were investigated by optical microscopy, X-ray diffraction, and were tested from biological point of view. Ag nanoparticles on nanocrystalline Si are important for their anti-microbial properties. In very low concentrations, Ag is highly toxic to germs while relatively non-toxic to human cells. Microbes are unlikely to develop a resistance against silver, as they do against conventional and highly targeted antibiotics. The experimental results sustain the Ag/Si nanocomposite structures as anti-microbial matrix

Increased Respiratory Activity in Light in Salt Stressed Synechocystis PCC 6803

In SynechocystisPCC 6803 the energetic changes associated with salt adaptation (0.5 M NaCl) include an increase in the respiratory activity (RA) both in dark (1-16) and in light (3) and an increased energy storage at the level of Photosystem I (PSI) (6,8, 17-19). Inspite of the development of our knowledge concerning the role of RA during salt adaptation both in vivo(1-16, 20-22) and in vitro(8—14,22) few major questions still remain, one of them being the occurrence and significance of RA in light (RAL), as originally put forward by Peschek’s group (9). The aim of this paper is to develop a new method to check respiratory electron transport in dark and in light in whole cells of SynechocystisPCC 6803, by potentiometric monitoring of the oxidation of artificial (2,6 dichlorophenolindophenol DCPIPred) and physiological (cyt. cred) electron donors, based on the usefulness of electrochemical method (mediated amperometry) to monitor in intact cyanobacteria RA in dark (1,20,23-25) and photosynthesis (23-25).