Critical Role of Lipid Scramblase TMEM16F in Phosphatidylserine Exposure and Repair of Plasma Membrane after Pore Formation

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Plant action: Multiple levels of regulation

This lecture is devoted to the relative contribution of various levels of regulation of the actin cytoskeleton functioning in the cell. Regulation at the levels of gene expression, mRNA and protein synthesis and stability, processes of actin polymerization/depolymerization and actin structures reorganization is briefly considered. Novel information about the pathways of signal transduction to the actin cytoskeleton with the involvement of Arp2/3 complex and RIC proteins is highlighted.     

Nonthermal Plasma‐Induced Degradation of Morin and Enhancement of Biological Activities

In the present study, non‐thermal dielectric barrier discharge (DBD) plasma of induced structural changes of morin resulted in the isolation of one previously undescribed benzofuranone derivative, along with two known compounds. The chemical structures of these degradation products were elucidated by UV, NMR and FAB‐MS spectroscopic analyses. The isolated three compounds showed potent antioxidative activities in two different tests, with IC₅₀ values in the range of 12.9–41.8 μm in the 2,2′‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS⁺) radical scavenging activity, 19.0–71.9 μm for hydroxyl radical scavenging activity test. Furthermore, the new methoxylated benzofuranone exhibited enhancement of inhibitory effects against pancreatic lipase with an IC₅₀ value of 90.7±1.6 μm , when compared to the parent morin. These results suggested that the degradation products isolated from plasma exposed morin might be beneficial for prevention of obesity and related diseases.     

Fibrinogen and fibrin in strong magnetic fields. Complementary results and discussion

When fibrin polymerizes in a strong magnetic field, it can be highly oriented. The structural diffraction study of the oriented polymer becomes thus possible. The magnetic birefringence can also be used to study the development of the polymer Fibrinogen in solution is weakly oriented in high magnetic fields. In this work we present complementary results and discussion. The validity of the comparison of the orientation parameters of fibrinogen and fibrin with those of other orientable known biological structures is discussed. The orientation of fibrin formed from fibrin monomer solution is compared to that of fibrin formed by the action of thrombin on fibrinogen. The conditions to obtain highly oriented fibrin gels suitable for three dimensional structure studies are also briefly discussed.     

The effects of deuterium oxide (2H2O) on the polymerization of tubulin in vitro

The initial rate and final extent of polymerization of both bovine brain tubulin and sea urchin egg tubulin were enhanced in the presence of ²H₂O. The yields were increased in association with the elevation of the ²H₂O concentration. ²H₂O also reduced the critical concentration for polymerization of brain tubulin. Thermodynamic analysis was attempted using the temperature dependence of the critical concentration for polymerization in the presence of ²H₂O. We obtained linear van 't Hoff plots and calculated thermodynamic parameters which were positive and were increased with the elevation of the ²H₂O concentration. The enhancement of the polymerization of tubulin by ²H₂O could, therefore, be the result of the strenghening of intra-and/or inter-molecular hydrophobic interactions of the tubulin molecules. We believe that the increase in lenghth and number of microtubules of the mitotic spindles in the dividing cells of the eukaryotes with ²H₂O may be caused by the direct involvement of ²H₂O in the polymerization of tubulin.     

Impact of seminal and serum zinc on semen quality and hormonal status: A population-based cohort study of Russian young men

BackgroundTrace elements are important factors in human reproductive health. Among them, special attention is paid to zinc, which is an essential trace element and is necessary for the normal functioning of the male reproductive system and the process of spermatogenesis. The aim of the study was to investigate the association between seminal and serum zinc concentrations and semen quality and reproductive hormone levels in population of Russian young men.MethodsThe study population consisted of 626 young Russian men (median age 22.5 years), recruited from the general population, regardless of their fertility status. Each participant provided semen and blood sample, information about his lifestyle and ethnicity. Semen quality (sperm concentration, motility and morphology), reproductive hormone levels (testosterone, estradiol, LH, FSH and inhibin B), and serum and seminal zinc concentrations were evaluated. The semen samples were analyzed according to the WHO laboratory manual (WHO, 2010). Serum hormones were measured by enzyme immunoassay, zinc concentrations were determined using spectrophotometry and direct colorimetry without deproteinization.ResultsZinc was present in the seminal plasma in a significantly higher concentration than in the blood serum (median serum Zn concentration was 23.6 μmol/L vs seminal Zn concentration 1571.8 μmol/L). The seminal zinc concentration was positively related to the total sperm count, sperm concentration, progressive motility and normal morphology (Spearman’s test: 0.221; 0.286; 0.269; 0.183, respectively, p < 0.001), while the serum Zn concentration was negatively related to serum testosterone and estradiol levels (r = −0.249 and r = −0.096, respectively, p < 0.001−0.05). It was found that the seminal Zn content in men with normal semen quality was higher compared to men with lowered semen quality (means: 6.37 and 5.03 μmol/ejaculate, respectively, p < 0.001). Similarly, the semen volume, total sperm count, sperm concentration, progressive motility, normal morphology and the serum testosterone level in men with the seminal Zn deficiency were lower than in men with the normal seminal Zn content.ConclusionBased on the results of our population-based study, seminal Zn levels were closely associated with semen parameters in young men, so Zn deficiency may be an important risk factor for lowered semen quality. Seminal Zn determinations should be considered as a useful tool in addition to other parameters in assessing male fertility.     

Purification of four gelatin-binding proteins from bovine seminal plasma by affinity chromatography

Bovine seminal plasma contains three similar acidic proteins, which we have previously designated as BSP-A1, BSP-A2, and BSP-A3. These proteins contain two homologous domains that are similar to type II structures present in the gelatin-binding domain of fibronectin. The present data have revealed that these proteins, like fibronectin, also form complexes with gelatin, a denatured collagen. Based on this property, a single step affinity purification method has been developed. In addition to these three proteins BSP-A1, -A2 and -A3, another protein with an apparent molecular weight of 30,000 dalton (named BSP-30-kDa) also bound to the gelatin-agarose column. Elution of these proteins from affinity columns using a linear gradient of either urea or arginine gave essentially the same pattern with a high yield of 90–95%. The purified proteins were homogeneous by SDS-polyacrylamide gel electrophoresis, amino acid composition and HPLC. Chromatography of bull seminal vesicular fluid also exhibited an elution pattern similar to that obtained for bull seminal plasma. The availability of these purified proteins should aid in understanding the physiology of these gelatin-binding proteins.     

Ca2+/Calmodulin Distinguishes Between Guanyl-5''-yl-Imidodiphosphate-and Opiate-Mediated Inhibition of Rat Striatal Adenylate Cyclase

The inhibition of adenylate cyclase from rat striatal plasma membranes by guanyl-5'-yl-imidodiphosphate [Gpp(NH)p] and morphine was compared to determine whether Gpp(NH)p-mediated inhibition accurately reflected hormone-mediated inhibition in this system. Inhibition of adenylate cyclase activity by Gpp(NH)p and morphine was examined with respect to temperature, divalent cation concentration, and the presence of Ca2+/calmodulin (Ca2+/CaM). Gpp(NH)p-mediated inhibition was dependent on the presence of Ca2+/CaM at 24 degrees C; the inhibition was independent of Ca2+/CaM at 18 degrees C; and inhibition could not be detected in the presence, or absence, of Ca2+/CaM at 30 degrees C. In contrast, naloxone-reversible, morphine-induced inhibition of adenylate cyclase was independent of both temperature and the presence of Ca2+/CaM. Mg2+ dose-response curves also reinforced the differences in the Ca2+/CaM requirement for Gpp(NH)p- and morphine-induced inhibition. Because Gpp(NH)p-mediated inhibition was independent of Ca2+/CaM at low basal activities (i.e., 18 degrees C, or below 1 mM Mg2+) and dependent on the presence of Ca2+/CaM at higher basal activities (24 degrees C, or above 1 mM Mg2+), the inhibitory effects of Gpp(NH)p were examined at 1 mM Mg2+ in the presence of 100 nM forskolin. Under these conditions, both Gpp(NH)p- and morphine-induced inhibition of adenylate cyclase were independent of Ca2+/CaM. The results demonstrate that the requirement for Ca2+/CaM to observe Gpp(NH)p-mediated inhibition depends on the basal activity of adenylate cyclase, whereas hormone-mediated inhibition is Ca2+/CaM independent under all conditions.(ABSTRACT TRUNCATED AT 250 WORDS)