Synthesis and phosphodiesterase 5 inhibitory activity of new 5-phenyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one derivatives containing an N-acylamido group phenyl ring.

New sildenafil analogues with an N-acylamido group at the 5'-position of the phenyl ring, 6a--e, were prepared from the readily available starting compound 2 in four straightforward steps. Enzyme assays demonstrated that all the target compounds 6a-e showed higher PDE5 inhibitory activities than sildenafil. It was observed that the PDE5 inhibitory activity was enhanced as the chain length of R group increased, but introduction of the branched alkyl groups such as isopropyl (6d) and cyclohexyl (6e) resulted in the drop of potency compared with 6c. In particular the N-butyrylamido derivative 6c exhibited the highest PDE5 inhibitory activity, and was about 6-fold more potent than sildenafil. However, all the compounds exhibited somewhat weak selectivity (1--3-fold) over PDE6, indicating that the compounds 6a--e have intrinsically lower selectivity than sildenafil.     

Cell separation from high cell density broths of Alcaligenes eutrophus by using a coagulant

Summary Alcaligenes eutrophus was successfully recovered from high cell density broths by pre-treatment with polyaluminium hydroxide chloride silicate as a coagulant at 36–90 mg Al/l. The optimum pH range for cell coagulation was 10–12. Subsequent centrifugation (45×g) and filtration (pore size 0.5 mm) gave a cell recovery of higher than 90%. The energy demand for cell recovery with the coagulant was only 3–11% of that without it.     

Propagation of recombinant vaccinia virus in HeLa cells: adsorption kinetics and replication in batch cultures.

The influence of various culture parameters on infection and replication of recombinant vaccinia virus in HeLa cells was examined during various phases of viral replication. A modified form of the model of Valentine and Allison (Biochim. Biophys. Acta 1960, 40, 393-399) model was used to predict successfully the viral adsorption rates in cell suspensions. An experimentally determined aggregation factor, epsilon, was included in the model to account for deviations of the observed adsorption rates from those predicted by the earlier model. It was also shown that the ionic strength, ionic species, and serum proteins present in the medium significantly altered the adsorption kinetics of the virus. The lysosomotropic base chloroquine was found to enhance viral infection more than 2-fold during the penetration step of viral infection. It was also demonstrated that cells infected during the exponential growth phase gave higher viral yields than those infected during the lag or stationary growth phases and the initial viral MOI did not significantly alter viral yields. Finally, it was demonstrated that viral infection of HeLa cells grown in 4-L bioreactor batch cultures resulted in increased death and glucose uptake rates and significantly lower growth rates.     

Hypertension resulting from overexpression of translationally controlled tumor protein increases the severity of atherosclerosis in apolipoprotein E knock-out mice

Hypertension is a well-established etiological factor for atherogenesis. We previously showed that transgenic mice overexpressing translationally controlled tumor protein (TCTP) develop systemic arterial hypertension. In this study we explored the cardiovascular effects of TCTP overexpression and possibly of the resultant hypertension on the severity of atherosclerosis in apolipoprotein E-deficient mice. Through multiple mating of TCTP-overexpressing transgenic mice (TCTP-TG) with apolipoprotein E knock-out mice (ApoE KO), we generated non-transgenic (nTG), TCTP-TG, nTG/ApoE KO and TCTP-TG/ApoE KO mice with similar genetic background. Male mice, 7-week old, were fed a lipid-enriched Western diet for 16?weeks, and blood pressure and body weight change were monitored every 2?weeks. Plasma lipid profiles and atherosclerotic lesions in aorta were quantified at the end of study. We found that blood pressure levels of TCTP-TG and TCTP-TG/ApoE KO, were similarly elevated while nTG and nTG/ApoE KO mice were normotensive. TCTP overexpression in ApoE KO mice led to significant exacerbation of atherosclerotic lesions. Feeding Western diet resulted in increases in total cholesterol, triglyceride (TG) and low density lipoprotein, and decreased high density lipoprotein (HDL) in ApoE KO mice. No significant differences were found in plasma lipid profiles of nTG/ApoE KO and TCTP-TG/ApoE KO. This study suggests that overexpression of TCTP, which induces hypertension, also accelerates the development of atherosclerotic lesion caused by high-fat and high-cholesterol diet without significantly altering plasma lipid profiles. We conclude that TCTP-induced hypertension could increase the severity of atherosclerotic lesion and suggest that inhibition of TCTP or its signaling pathways may be a potential approach to the therapy of both diseases, hypertension and atherosclerosis.     

Synthesis and antifungal activity of 1H-indole-4,7-diones

1H-Indole-4,7-diones were synthesized and tested for in vitro antifungal activity against fungi. The synthesized 1H-indole-4,7-diones generally showed good antifungal activity against Candida krusei, Cryptococcus neoformans, and Aspergillus niger. The results suggest that 1H-indole-4,7-diones would be potent antifungal agents.     

Effects of daunorubicin on ganglioside expression and neuronal differentiation of mouse embryonic stem cells

Gangliosides are implicated in neuronal development processes. The regulation of ganglioside levels is closely related to the induction of neuronal cell differentiation. In this study, the relationship between ganglioside expression and neuronal cell development was investigated using an in vitro model of neural differentiation from mouse embryonic stem (mES) cells. Daunorubicin (DNR) was applied to induce the expression of gangliosides in embryoid body (EB) (4+). We observed an increase in expression of gangliosides in all stages of EBs by treatment of DNR (2microM). High-performance thin-layer chromatography (HPTLC) showed that gangliosides GD3, GD1a, GT1b, and GQ1b increased in DNR-treated 7-day-old EB (4+) [EB (4+):7]. DNR treatment significantly increased the expression of gangliosides, especially GT1b and GQ1b in comparison to control cells. Interestingly, GQ1b co-localized with microtubule-associated protein 2 (MAP-2) expressing cells in DNR-treated EB (4+):7. The co-localization of GQ1b and MAP-2 was found in neurite-bearing cells in DNR-treated 15-day-old EB (4+) [EB (4+):15], whereas no significant expression of GQ1b and less neurite formation were observed in untreated control. Also, the expression of synaptophysin and NF200, both neuronal markers associated with neruites, was increased by DNR treatment. These results demonstrate that DNR increases expression of gangliosides, especially GQ1b, in differentiating neuronal cells. Further, neurite-bearing neuronal cell differentiation can be facilitated by DNR, possibly through the induction of gangliosides. Thus, the present data suggest that DNR is beneficial for facilitating neuronal differentiation from ES cells and among the gangliosides analyzed in the present study, GQ1b is mainly involved in neurite formation.     

Biological and biochemical modulation of Trichomonas vaginalis KT9 isolate after shifting of culture medium from TPS-1 into TYM

To evaluate the biological and biochemical characteristics of Trichomonas vaginalis KT9 isolate, the growth and size of trichomonads, pathogenicity in mouse, protein profiles and proteinase activity were examined after shifting the medium from TPS-1 into TYM. Generation time of trichomonads in TYM medium was 4.5 hr in comparison to TPS-1 with 7.1 hr. Size of trichomonads cultured in TPS-1 medium (8.5 ± 0.9 × 6.0 ± 0.9 µm) was significantly smaller than those in TYM medium (10.9 ± 1.4 × 8.2 ± 0.9 µm). Trichomonads cultured in TYM medium produced subcutaneous abscess in 9 out of 10 mice, whereas those in TPS-1 medium produced abscesses in 2 out of 10 mice. In SDS-PAGE, trichomonad lysates from both media showed ten common bands. However, trichomonads in TYM medium showed additional bands of 136 kDa, 116 kDa and 40 kDa in comparison to those in TPS-1 with 100 kDa. By immunoblot with T. vaginalis-immunized rabbit sera, T. vaginalis cultivated in both TYM and TPS-1 media showed 5 common bands, and unique bands of 116 kDa, 105 kDa, and 86 kDa were observed in trichomonads in TYM while a 140 kDa band in those in TPS-1. In gelatin SDS-PAGE, trichomonads in TYM degraded gelatin stronger than those in TPS-1. Also protease activity of trichomonads in TYM was significantly higher than that of trichomonads in TPS-1 using Bz-Pro-Phe-Arg-Nan as a substrate. According to the results, it is assumed that the shift from TPS-1 into TYM medium for cultivation of T. vaginalis might modulate the biological and biochemical properties of T. vaginalis in vitro.     

How do organic solvents affect peroxidase structure and function?

The effect of organic solvents on horseradish peroxidase structure and function has been studied. Some, but not complete, enzyme denaturation occurs even in low volumes of water-miscible organic solvents (e.g., greater than 30% v/v dioxane, greater than 50% v/v methanol, and greater than 20% v/v acetonitrile) as determined by the decreased difference between the fluorescence of peroxidase's sole tryptophan residue and free L-tryptophan in solution. Absorbance and electron paramagnetic resonance spectroscopies indicate exposure of peroxidase's active site to the organic solvent. This reduces the local polarity in the enzyme's active site and results in stronger hydrogen bonding of phenolic substrates to the enzyme. In extreme cases (e.g., 95% v/v dioxane, 90% v/v acetonitrile, and ethyl and butyl acetate containing 2 and 1% v/v aqueous buffer, respectively), the transition state of the enzymic reaction is sufficiently perturbed so as to alter the magnitude of the Hammett rho value. This is most likely the result of the increased strength of hydrogen bonding between electron-donating alkoxyphenols (negative sigma values) and an electrophilic group in the enzyme's active site, thereby reducing catalytic efficiencies for such substrates relative to alkyl- and chlorophenols. Perhaps the most important effect of the organic solvent, however, is the significant ground-state stabilization of phenolic substrates in organic media as opposed to aqueous buffer. This stabilization can account for nearly 4 orders of magnitude in reduction of catalytic efficiency and is manifested in increased Km's. This study indicates that enzymes can maintain much of their native active-site structure in organic media and that the effect of solvent on substrate thermodynamics must be considered.     

Purification and characterization of a cytosolic, 42-kDa and Ca2+-dependent phospholipase A2 from bovine red blood cells: its involvement in Ca2+-dependent release of arachidonic acid from mammalian red blood cells

It has become evident that a Ca(2+)-dependent release of arachidonic acid (AA) and subsequent formation of bioactive lipid mediators such as prostaglandins and leukotrienes in red blood cells (RBCs) can modify physiological functions of neighboring RBCs and platelets. Here we identified a novel type of cytosolic PLA(2) in bovine and human RBCs and purified it to apparent homogeneity with a 14,000-fold purification. The purified enzyme, termed rPLA(2), has a molecular mass of 42 kDa and reveals biochemical properties similar to group IV cPLA(2), but shows different profiles from cPLA(2) in several column chromatographies. Moreover, rPLA(2) did not react with any of anti-cPLA(2) and anti-sPLA(2) antibodies and was identified as an unknown protein in matrix-assisted laser desorption/ionization time-of-flight mass spectrometric analysis. Divalent metal ions tested exhibited similar effects between rPLA(2) and cPLA(2), whereas mercurials inhibited cPLA(2) but had no effect on rPLA(2). Antibody against the 42-kDa protein not only precipitated the rPLA(2) activity, but also reacted with the 42-kDa protein from bovine and human RBCs in immunoblot analysis. The 42-kDa protein band was selectively detected in murine fetal liver cells known as a type of progenitor cells of RBCs. It was found that EA4, a derivative of quinone newly developed as an inhibitor for rPLA(2), inhibited a Ca(2+) ionophore-induced AA release from human and bovine RBCs, indicating that this enzyme is responsible for the Ca(2+)-dependent AA release from mammalian RBCs. Finally, erythroid progenitor cell assay utilizing diaminobenzidine staining of hemoglobinized fetal liver cells showed that rPLA(2) detectable in erythroid cells was down-regulated when differentiated to non-erythroid cells. Together, our results suggest that the 42-kDa rPLA(2) identified as a novel form of Ca(2+)-dependent PLA(2) may play an important role in hemostasis, thrombosis, and/or erythropoiesis through the Ca(2+)-dependent release of AA.