Optimization of antimalarial,and anticancer activities of (E)-methyl 2-(7-chloroquinolin-4-ylthio)-3-(4-hydroxyphenyl) acrylate

Chemically modified versions of bioactive substances, are particularly useful in overcoming barriers associated with drug formulation, drug delivery and poor pharmacokinetic properties. In this study, a series of fourteen (E)-methyl 2-(7-chloroquinolin-4-ylthio)-3-(4-hydroxyphenyl) acrylate (2–15) were prepared by using a one step synthesis from 1 previously described by us as potential antimalarial and antitumor agent. Molecules were evaluated as inhibitors of β-hematin formation, where most of them showed a significant inhibition value (%?>?70). The best inhibitors were tested in vivo as potential antimalarials in mice infected with P. berghei ANKA, chloroquine susceptible strain. Three of them (5, 6, and 15) displayed antimalarial activity comparable to that of chloroquine. Also, molecules were evaluated for their cytotoxic activity against two human cancer cell lines (Jurkat E6.1 and HL60) and primary culture of human lymphocytes. Most of the synthesized compounds, except for analogs 2–6, 8, and 10–12, displayed cytotoxicity against cancer cell lines without affecting normal cells. The potency of the compounds was 15???1, and 14?>?7, 9, and 13. Flow cytometry analysis demonstrated an increase in apoptotic cell death after 24?h. The compounds may affect tumor cell autophagy and consequently increase cell apoptosis.     

Differential role of programmed death-ligand 1 [corrected] and programmed death-ligand 2 [corrected] in regulating the susceptibility and chronic progression of experimental autoimmune encephalomyelitis

Programmed death-1 (PD-1) is a negative costimulatory molecule, and blocking the interaction of PD-1 with its ligands, PD-L1 (B7-H1) and PD-L2 (B7-DC), enhances autoimmune disease in several animal models. We have studied the role of PD-1 ligands in disease susceptibility and chronic progression in experimental autoimmune encephalomyelitis (EAE). In BALB/c mice immunized with myelin oligodendrocyte glycoprotein (MOG) peptide 35-55, PD-L1 but not PD-L2 blockade significantly increased EAE incidence. In B10.S mice immunized with myelin proteolipid protein (PLP) peptide 139-151, both PD-L1 and PD-L2 blockade markedly enhanced EAE severity. In prediabetic NOD mice immunized with PLP48-70, PD-L2 blockade worsened EAE but did not induce diabetes, whereas PD-L1 blockade precipitated diabetes but did not worsen EAE, suggesting different regulatory roles of these two ligands in EAE and diabetes. B6 mice immunized with MOG35-55 developed chronic persistent EAE, and PD-L2 blockade in the chronic phase exacerbated EAE, whereas PD-L1 blockade did not. In contrast, SJL/J mice immunized with PLP139-151 developed chronic relapsing-remitting EAE, and only PD-L1 blockade during remission precipitated EAE relapse. The strain-specific effects of PD-1 ligand blockade did not correlate with the expression of PD-L1 and PD-L2 on dendritic cells and macrophages in lymphoid tissue, or on inflammatory cells in the CNS. However, EAE enhancement is correlated with less prominent Th2 cytokine induction after specific PD-1 ligand blockade. In conclusion, PD-L1 and PD-L2 differentially regulate the susceptibility and chronic progression of EAE in a strain-specific manner.     

Disorders of the Menstrual Cycle in Elite Female Ice Hockey Players and Figure Skaters

The purpose of this study was to assess and compare the incidence of delayed menarche and menstrual dysfunction among elite ice hockey players and figure skaters. Forty-three ice hockey players (23.5 ± 4.8 years, 68.2 ± 1.2 kg, 1.68 ± 0.01 m) and 39 figure skaters (17.5 ± 3.4 years, 53.7 ± 5.8 kg, 1.64 ± 0.05 m) completed a self-administered questionnaire on their menstrual status and history, training regimens and lifestyle. Age at menarche did not differ significantly between ice hockey players (13.3 ± 1.3 years) and figure skaters (13.7 ± 1.4 years). Menarche was unrelated to nationality, vigorous training premenarche or age at which the athlete began her sport, but was correlated with the age at menarche of the athletes’ mothers (r = 0.39, p < 0.05). Hormonal contraceptives were used by 35% of ice hockey players and 15% of the figure skaters. Amenorrhea and oligomenorrhea were experienced by 7.1% and 38.7% of postmenarcheal, ice hockey players and figure skaters respectively not using hormonal contraceptives. Menstrual dysfunction was associated with both age and age at menarche in the ice hockey players only. Training factors, and psychological pressure were perceived by the athletes to contribute to menstrual dysfunction. A greater training volume, younger age at commencing sport, lower body mass, greater subjective body image pressure and younger biological and gynaecological age were reported among the figure skaters, and were proposed to explain the higher incidence of menstrual dysfunction among the figure skaters compared with the ice hockey players. Figure skaters appear at increased risk of amenorrhea and oligomenorrhea compared with ice hockey players, which may be linked to training and physical characteristics of the sports.     

Characterization of Salmonella enterica Serovar Typhimurium from Marine Environments in Coastal Waters of Galicia (Spain)

Twenty-three Salmonella enterica serovar Typhimurium isolates from marine environments were characterized by phage typing, pulsed-field gel electrophoresis (PFGE) analysis, plasmid analysis, and antibiotic resistance, and the distribution of the different types in the coastal waters were subsequently analyzed. Five phage types were identified among the isolates (PT41, PT135, PT99, DT104, and DT193). PT135 isolates were exclusively detected during the winter months from 1998 to 2000, whereas DT104 and PT41 isolates were detected exclusively in the summer months from 2000 to 2002. XbaI PFGE analysis revealed 9 PFGE types, and plasmid profiling identified 8 plasmid types (with 1 to 6 plasmids) among the isolates. Only three isolates presented multidrug resistance to antibiotics. Two DT104 isolates were resistant to 8 and 7 antibiotics (profiles ACCeFNaSSuT and ACeFNeSSuT), whereas a PT193 isolate presented resistance to 6 antibiotics (profile ACFSSu). In addition, four PT41 isolates were resistant to a single antibiotic. The detection of multidrug-resistant phage types DT104 and DT193 in shellfish emphasizes the importance of monitoring the presence of Salmonella in routine surveillance of live bivalve molluscs.     

Effect of Mg, Si, and Sr on growth and antioxidant activity of the marine microalga Tetraselmis suecica

Efforts to increase the productivity of microalgal cultures have been focused on the improvement of photobioreactors, but little attention has been paid to the nutritional requirements of microalgae in order to improve culture media formulation. In this study, the main goal was obtaining a high productivity for Tetraselmis suecica (Chlorophyta) in semicontinuous culture by adding magnesium (Mg), silicon (Si), and strontium (Sr) at concentrations from 0.01 to 10 mM; at the time, the effect on steady-state cell density, biochemical composition, and antioxidant activity of T. suecica was evaluated. Because productivity is higher in high-density cultures, the work was focused many times to cell density. Mg (3 mM) and Sr (0.1 mM) added separately reached the highest steady-state cell density (7.0?×?10⁶?±?0.4 cells mL^?1) in comparison to control (4.2?±?0.1 cells mL^?1), but simultaneous addition had a synergic effect, achieving 8.7?×?10⁶?±?0.6 cells mL^?1. Silicon (3 mM) significantly affected the steady-state cell density, reaching 6.0?±?0.3 cells mL^?1 and increased the cell ash-free dry weight, reaching 127?±?7.9 pg cell^?1 in comparison to control (102.7?±?5.0 pg cell^?1), resulting in an ash-free dry weight productivity of 0.75?±?0.07 g?L^?1 day^?1. The highest fatty acids content and antioxidant activity, measured by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) method were obtained with Sr 10 mM. Sr treatments showed a high correlation (R ²?=?0.98) between DPPH inhibition and polyphenolic content, explaining its high antioxidant activity. Therefore, the addition of Mg, Si, and Sr to culture medium of T. suecica is recommended to achieve high steady-state cell density in semicontinuous cultures.     

Site-directed mutagenesis study of the microenvironment characteristics of Lys213 of Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase

Saccharomyces cerevisiae phosphoenolpyruvate (PEP) carboxykinase catalyzes the reversible formation of oxaloacetate and adenosine triphosphate from PEP, adenosine diphosphate and carbon dioxide, and uses Mn(2+) as the activating metal ion. Comparison with the crystalline structure of homologous Escherichia coli PEP carboxykinase [Tari et al. Nature Struct. Biol. 4 (1997) 990-994] shows that Lys(213) is one of the ligands to Mn(2+) at the enzyme active site. Coordination of Mn(2+) to a lysyl residue is infrequent and suggests a low pK(a) value for the epsilon-NH(2) group of Lys(213). In this work, we evaluate the role of neighboring Phe(416) in contributing to provide a low polarity microenvironment suitable to keep the epsilon-NH(2) of Lys(213) in the unprotonated form. Mutation Phe416Tyr shows that the introduction of a hydroxyl group in the lateral chain of the residue produces a substantial loss in the enzyme affinity for Mn(2+), suggesting an increase of the pK(a) of Lys(213). A study of the effect of pH on K(m) for Mn(2+) indicate that the affinity of recombinant wild type enzyme for the metal ion is dependent on deprotonation of a group with pK(a) of 7.1+/-0.2, compatible with the low pK(a) expected for Lys(213). This pK(a) value increases at least 1.5 pH units upon Phe416Tyr mutation, in agreement with the expected effect of an increase in the polarity of Lys(213) microenvironment. Theoretical calculations of the pK(a) of Lys(213) indicate a value of 6.5+/-0.9, and it increases to 8.2+/-1.6 upon Phe416Tyr mutation. Additionally, mutation Phe416Tyr causes a loss of 1.3 kcal mol(-1) in the affinity of the enzyme for PEP, an effect perhaps related to the close proximity of Phe(416) to Arg(70), a residue previously shown to be important for PEP binding.     

Formation of domoic acid and fatty acids inPseudonitzschia pungens f.multiseries with scale of culture

Pseudonitzschia pungens f.multiseries was cultured in 20-L polycarbonate carboys, 350-L fibreglass columns and 500-L plastic bags to determine the effects of medium enrichment and scale of culture on cell yield, production of cellular domoic acid and formation of fatty acids, particularly the potential tracer acid 16:4n-1. Cell concentrations were highest in seawater enriched with stock levels of nitrate and phosphate, but with double the stock level of silicate, at all scales of culture. Cellular toxin in 20, 350 and 500-L cultures averaged 0.32, 0.04 and 2.56 pg cell^-1 and was independent of medium used. The order of magnitude difference in levels of cellular toxin was considered to reflect the varying levels of irradiance within the culture vessels. Support was given to this by the significant difference in content of total cellular fatty acids, due principally to the algal storage acid 16: 1n-7, which is known to be influenced by irradiance. Levels of cellular domoic acid correlated significantly with total fatty acids in 350 and 500-L cultures. Bag cultures producing significantly higher levels of cellular domoic acid provided lower relative proportions of 16:4n-1, which limited its use as a tracer for food-web studies.