The effect of xylene inhalation on the rat liver

In this study, 11,284 mg/m3 (2600 ppm) of xylene was administered for 8 hours a day to pregnant rats by means of inhalation, starting from the sixth day of their pregnancies. Furthermore, while a group of non-pregnant rats inhaled the same amount of xylene during the same period, the control group inhaled clean air. Consequently, in addition to the embryotoxic effects of xylene, the effects on the various tissues of the mothers and their litters were observed light and electron microscopes. No external anomalies were observed in any of the rats born at the end of the 21st day, and there were no macroscopic defects in their organs either. While following xylene inhalation no structural defects in the kidney and pancreas was found, expansions in the smooth endoplasmic reticulum of the liver tissues, increases in the lysosomes, and defective mitochondrion structures were found in the pregnant and non-pregnant rats. It was noticed that xylene in particular caused structural defects in the liver of the fetus. Compared to the control groups, increases were observed in the activities of the AST, ALT, ALP, and Arginase enzymes in the liver.     

Differences in response to activation of adenylyl cyclase by various stimulants in human myocardium

The response of adenylyl cyclase complex in human atrial tissue removed at corrective surgery of normoxemic and hypoxemic congenital heart defects in children to various stimulants was evaluated and related to the oxygenation state of the myocardium. When comparing response to stimulation in normoxemic and hypoxemic atria a higherbasal as well as stimulated adenylyl cyclase activity was found in hypoxemic atria; an insignificant stimulatory effect of isoprenaline in normoxemic hearts became significant in the atria of hypoxemic patients. Hypoxemic samples also showed two times higher activity when the total catalytic activity was evaluated by the stimulation with forskolin. Higher stimulatory effect of Gpp/NH/p was also observed in hypoxemic than in normoxemic state. Increased adenylyl cyclase activity might represent one of adaptive mechanisms to hypoxemia in patients with congenital heart defects.     

Stability of a recombinant plasmid carrying a-amylase gene in Bacillus subtilis

Plasmid pSB6 is a streptococcal recombinant plasmid carrying the a-amylase gene of Bacillus amyloliquefaciens and the chloramphenicol resistance gene. The segregational and structural instabilities of this plasmid were examined under non-selective conditions in Bacillus subtilis. These instabilities were modelled according to a kinetic expression derived from the difference in the growth between plasmid-bearing and plasmid-free cells. This plasmid showed slight segregational instability and much higher levels of structural instability under the conditions examined.     

The phosphatase activity of the isolated H4-H5 loop of Na+/K+ ATPase resides outside its ATP binding site.

The structural stability of the large cytoplasmic domain (H(4)-H(5) loop) of mouse alpha(1) subunit of Na(+)/K(+) ATPase (L354-I777), the number and the location of its binding sites for 2'-3'-O-(trinitrophenyl) adenosine 5'-triphosphate (TNP-ATP) and p-nitrophenylphosphate (pNPP) were investigated. C- and N-terminal shortening revealed that neither part of the phosphorylation (P)-domain are necessary for TNP-ATP binding. There is no indication of a second ATP site on the P-domain of the isolated loop, even though others reported previously of its existence by TNP-N(3)ADP affinity labeling of the full enzyme. Fluorescein isothiocyanate (FITC)-anisotropy measurements reveal a considerable stability of the nucleotide (N)-domain suggesting that it may not undergo a substantial conformational change upon ATP binding. The FITC modified loop showed only slightly diminished phosphatase activity, most likely due to a pNPP site on the N-domain around N398 whose mutation to D reduced the phosphatase activity by 50%. The amino acids forming this pNPP site (M384, L414, W411, S400, S408) are conserved in the alpha(1-4) isoforms of Na(+)/K(+) ATPase, whereas N398 is only conserved in the vertebrates' alpha(1) subunit. The phosphatase activity of the isolated H(4)-H(5) loop was neither inhibited by ATP, nor affected by mutation of D369, which is phosphorylated in native Na(+)/K(+) ATPase.     

Function changing mutations in glucocorticoid receptor evolution correlate with their relevance to mode coupling

Nonlinear effects in protein dynamics are expected to play role in function, particularly of allosteric nature, by facilitating energy transfer between vibrational modes. A recently proposed method focusing on the non‐Gaussian shape of the configurational population near equilibrium projects this information onto real space in order to identify the aminoacids relevant to function. We here apply this method to three ancestral proteins in glucocorticoid receptor (GR) family and show that the mutations that restrict functional activity during GR evolution correlate significantly with locations that are highlighted by the nonlinear contribution to the near‐native configurational distribution. Our findings demonstrate that the analysis of nonlinear effects in protein dynamics can be harnessed into a predictive tool for functional site determination. Proteins 2016; 84:655–665. © 2016 Wiley Periodicals, Inc.     

Cytotoxic and apoptotic effects of boron compounds on leukemia cell line

In this study we investigated the effects of boric acid and sodium tetraborate on an acute leukemia cell line and healthy human lymphocytes. We evaluated the effects of boric acid and sodium tetraborate on the HL-60 cell line and healthy human lymphocytes by using the methods of MTT, Neutral Red, AO (flow cytometry) and transmission electron microscope. We found that there were dead cells at a concentration of 500 µM boric acid and sodium tetraborate (50 % and 40 %, respectively). An apoptotic effect was found at a concentration of 1,000 µM concentration in normal lymphocytes and HL-60 (acute leukemia cells) cells (2.5 % and 8.8 % respectively). We observed that boric acid at a concentration of 500 µM caused double nucleus and micronucleus formation in both HL-60 cells and lymphocytes. An expansion in mitochondrial dimension and deformation in cristas also appeared. Our findings suggest that boric acid is more effective than sodium tetraborate on the HL-60, and boric acid in particular showed a cytotoxic effect on HL-60 in comparison to healthy lymphocytes and it also affected the mitochondrial pathway.