Characteristics of enhanced biological phosphorus removal (EBPR) process under the combined actions of intracellular and extracellular polyphosphate.

The characteristics of enhanced biological phosphorus removal (EBPR) process under the combined actions of intracellular and extracellular polyphosphate (polyP) were investigated with the 31P Nuclear Magnetic Resonance (NMR) and the fractionation extracting the loosely-bound and tightly-bound extracellular polymer substances (i.e., LB-EPS and TB-EPS) and bacterial cells in EBPR sludge. The hydrolysis/synthesis of extracellular and intracellular polyP was a key step of the phosphate migration and transformation in EBPR sludge. The orthophosphate (orthoP) produced from the intracellular and extracellular polyP anaerobic-hydrolysis was partially accumulated in the bacterial cells and TB-EPS, and then the accumulated orthoP was main composition for these polyP aerobic-synthesis. Importantly, the anaerobic-hydrolysis enhancement of intracellular and extracellular ployP could promote EBPR sludge to absorb volatile fatty acids (VFAs) followed by being transformed into intracellular poly-hydroxy-alkanoates (PHAs). The mechanism for VFAs passing through the LB-EPS and TB-EPS should be an anion-exchange action between orthoP and VFAs. The orthoP accumulation in the TB-EPS kept an orthoP concentration gradient among the TB-EPS, LB-EPS and bulk solution, driving orthoP and VFAs migrations. The orthoP accumulation in the bacterial cells could keep an orthoP concentration difference between the cell-membrane two sides of phosphorus accumulating organisms (PAOs) to promote VFAs passing through the cell membrane considered as an anion exchange membrane. The intracellular PHAs continuously hydrolyzed accompanied with the average chain-length increases of the extracellular and intracellular polyP during the whole aerobic stage. Additionally, the energy of the extracellular polyP synthesized in situ should came from the intracellular PHAs hydrolysis.

A Flavonoid Compound Promotes Neuronal Differentiation of Embryonic Stem Cells via PPAR-ß Modulating Mitochondrial Energy Metabolism.

Relatively little is known regarding mitochondrial metabolism in neuronal differentiation of embryonic stem (ES) cells. By using a small molecule, present research has investigated the pattern of cellular energy metabolism in neural progenitor cells derived from mouse ES cells. Flavonoid compound 4a faithfully facilitated ES cells to differentiate into neurons morphologically and functionally. The expression and localization of peroxisome proliferator-activated receptors (PPARs) were examined in neural progenitor cells. PPAR-ß expression showed robust upregulation compared to solvent control. Treatment with PPAR-ß agonist L165041 alone or together with compound 4a significantly promoted neuronal differentiation, while antagonist GSK0660 blocked the neurogenesis-promoting effect of compound 4a. Consistently, knockdown of PPAR-ß in ES cells abolished compound 4a-induced neuronal differentiation. Interestingly, we found that mitochondrial fusion protein Mfn2 was also abolished by sh-PPAR-ß, resulting in abnormal mitochondrial Ca2+ ([Ca2+]M) transients as well as impaired mitochondrial bioenergetics. In conclusion, we demonstrated that by modulating mitochondrial energy metabolism through Mfn2 and mitochondrial Ca2+, PPAR-ß took an important role in neuronal differentiation induced by flavonoid compound 4a.

[Establishment of optimized neuronal differentiation-promoting model derived from P19 embryonic carcinoma cells].

OBJECTIVE: To establish an optimized primary drug screen model of neuronal differentiation using P19 embryonal carcinoma cells. METHODS: The final concentration of retinoid acid (RA), days of suspension culture, manner of adherent culture, suitable cell density and adherent culture medium were tested, respectively. Two stages of neuronal differentiation were examined based on morphological changes and immunocytochemistry analysis of neuronal specific protein ß-tubulin III. RESULTS: On d 8 of differentiation culture, neuron-like cells were observed with final concentration of 1 µmol/L RA. Neuron-like network was formed on d 16 of neuronal differentiation. ß-tubulin III was positively stained on both stages, indicating P19 cells were differentiated into neurons. CONCLUSION: The model using RA to induce P19 embryonic carcinoma cells to differentiate into neuron-like cells has been successfully established, which may provide a rapid, phenotypic cell-based platform for primary screening of neurogenesis-promoting drugs.

2,3,4,6-Tetra-O-acetyl-ß-d-galacto-pyrano-syl butyrate.

The title compound, C(18)H(26)O(11), was synthesized by a condensation reaction of 2,3,4,6-tetra-O-acetyl-α-d-galactopyranosyl bromide and butyric acid. The acet-oxy-methyl and butyrate groups are located on the same side of the pyran ring, showing the ß configuration for the d-glycosyl ester; the butyl group adopts an extend conformation, the C-C-C-C torsion angle being 179.1 (7)°. In the crystal, the mol-ecules are linked by weak C-H⋯O hydrogen bonds.

Promoting effects of isobavachin on neurogenesis of mouse embryonic stem cells were associated with protein prenylation.

AIM: Some small molecules can induce mouse embryonic stem (ES) cells to differentiate into neuronal cells. Here, we explored the effect of isobavachin (IBA), a compound with a prenyl group at position 8 of ring A, on promoting neuronal differentiation and the potential role of its protein prenylation. METHODS: The hanging drop method was employed for embryonic body (EB) formation to mimic embryo development in vivo. The EBs were treated with IBA at a final concentration of 10(-7) mol/L from EB stage (d 4) to d 8+10. Geranylgeranyltransferase I inhibitor GGTI-298 was subsequently used to disrupt protein prenylation. Neuronal subtypes, including neurons and astrocytes, were observed by fluorescence microscopy. Gene and protein expression levels were detected using RT-PCR and Western blot analysis, respectively. RESULTS: With IBA treatment, nestin was highly expressed in the neural progenitors generated from EBs (d 4, d 8+0). EBs then further differentiated into neurons (marked by ß-tubulin III) and astrocytes (marked by GFAP), which were both up-regulated in a time-dependent manner on d 8+5 and d 8+10. Co-treatment with GGTI-298 selectively abolished the IBA-induced neuronal differentiation. Moreover, in the MAPK pathway, p38 and JNK phosphorylation were down-regulated, while ERK phosphorylation was up-regulated after IBA treatment at different neuronal differentiation passages. CONCLUSION: IBA can facilitate mouse ES cells differentiating into neuronal cells. The mechanism involved protein prenylation and, subsequently, phos-ERK activation and the phos-p38 off pathway.

Synthesis and structure-activity relationship studies of cytotoxic cinnamic alcohol derivatives.

Three series of di- and trisubstituted derivatives of cinnamic alcohol and its conjugated dienol analogues were designed and synthesised. The derivatives were screened for cytotoxicity against nine tumour cell lines: KB, A549, Hela, CNE, PC-3, BEL-7404, HL-60, BGC823 and P388D1. Most of the cinnamic alcohol derivatives showed cytotoxic activity. The compound 7-(4',5'-dichlorobenzyloxy)-6,8-dihydroxycinnamic alcohol (55) exhibited significant cytotoxicity to seven human tumour cell lines on a micromolar range, especially with regard to the KB and P388D1 cell lines, showing IC(50) values of 0.4 and 0.5 µM, respectively. The structure-activity relationships of the derivatives are discussed.

A facile chemoenzymatic approach: one-step syntheses of monoterpenoid indole alkaloids.

Facile chemoenzymatic syntheses of cytotoxic monoterpenoid indole alkaloids with novel skeletons and multiple chiral centers are described. Synthesis of these alkaloids was achieved by a simple one-step reaction using strictosidine and 12-aza-strictosidine as the key intermediates. Strictosidines were prepared by coupling of secologanin with tryptamine and 7-aza-tryptamine, respectively, using the immobilized recombinant Rauvolfia strictosidine synthase. A detailed stereochemical analysis is presented herein. The results provide an opportunity for a chemoenzymatic approach that leads to an increased diversification of complex alkaloids with improved structures and activities.

[4, 8-disubstituted-8, 9-dihydro-pyrazine[2,3-g]quinazoline-7(6H)-ketones: a novel class of antitumor agents].

OBJECTIVE: To evaluate the antitumor activity of a novel class of 4, 8-Disubstituted-8, 9-dihydropyrazine[2, 3-g]quinazoline-7(6H)-ketones in vitro, and to screen potential anticancer compounds for further study. METHODS: Seventeen compounds of 4, 8-Disubstituted-8, 9-dihydropyrazine[2, 3-g]quinazoline-7(6H)-ketones were synthesized with solid-phase method for biological evaluation of EGFR tyrosine kinase. MTT method was used to evaluate the cytotoxic activity in vitro against three human cancer cell lines (human lung carcinoma cell line A549, human leukemia cell lines K562 and human gastric carcinoma cell line SGC7901). RESULTS: Compound 7-13 and 7-14 showed potent antitumor activities against A549 cells, with IC(50) values of 8.10 and 8.12 mol/L, respectively. Eight compounds showed proliferative inhibition effect on K562 cells, especially 7-2, 7-13 and 7-17, with IC(50) values of 2.22,0.57 and 7.20 mol/L,respectively.And compound 7-13 and 7-3 showed potent antitumor activity against SGC7901 cells, with IC(50) values of 4.20 and 9.71 mol/L, respectively. CONCLUSION: The synthesized compounds 4, 8-Disubstituted-8, 9-dihydropyrazine[2, 3-g] quinazoline-7(6H)-ketones show inhibition effects on human cancer cell lines in vitro. Compound 7-13 has anticancer activity in all three cancer cell lines, which might be used as a potential antitumor drug for further study.

[Transcription of cytoskeleton protein genes in differentiation of neurons from mouse embryonic stem cells induced by small molecules].

OBJECTIVE: To investigate the transcription of cytoskeleton protein genes in differentiation of neurons from mouse embryonic stem (ES) cells induced by all-trans retinoic acid (RA), and to explore the possibility of setting up a method to screen small molecules with promoting or inhibiting effect. METHODS: The hanging drop method was employed for embryonic body formation to mimic embryo development in vivo. Reverse transcriptase PCR (RT-PCR) was performed to investigate mRNA expression of the neuron-specific cytoskeleton proteins including Mtap2, Nefm and beta-tubulin III which were regarded as the inducing effect indexes of RA. Morphological evaluation and immunocytochemistry staining were conducted to identify the neural derivatives. Moreover, the inducing effects of six synthetic molecules were further evaluated. RESULT: RA up-regulated the mRNA expression of Mtap2 and Nefm, especially Mtap2 increased by 1.27 times, which was consistent with the morphological alteration. However, there was no significant changes of beta-tubulin III expression. With addition of the six synthetic molecules, the transcription of Mtap2 was inhibited, while the Nefm mRNA expression was up-regulated in some degree, especially for molecule 1 and 3 that was increased by 1.4 and 1.2 times, which, however, was not parallel to the morphological changes. CONCLUSION: The transcriptional levels of Mtap2 and Nefm are both up-regulated in the RA-induced differentiation of ES cells towards neurons. The up-regulation of Mtap2 is consistent with the morphological alteration, which might be the key landmark in the RA-induced differentiation of ES cells into neurons.

MAPEG expression in mouse embryonic stem cell-derived hepatic tissue system.

The expressions of membrane-associated proteins in eicosanoid and glutathione metabolism (MAPEG), a superfamily involved in both inflammation and cell protection, were investigated in an in vitro system of mouse embryonic stem (ES) cell-derived hepatic tissue. Gene expressions of all MAPEG members were demonstrated in a developmental-dependent manner in the derived hepatic tissue. The protein expression of microsomal glutathione S-transferase 1 (MGST1) was not detected until differentiating day 14. It gradually increased by maturation of hepatic tissue. The microsomes of ES cell-derived hepatic tissue possessed the MGST1-like catalytic activity. However, MGST1 from the microsome preparation could not form dimers as usual when exposed to reactive nitrogen species ONOO. Among the other members in MAPEG, weak expressions of leukotriene C(4) synthase (LTC(4)S) and microsomal prostaglandin E synthase 1 (mPGES-1) were observed. A stable expression of 5-Lipoxygenase activating protein (FLAP) appeared during the entire course of differentiation. MGST2 and MGST3 failed to express in the derived hepatic tissue, although mRNA of them do existed. In conclusion, ES cell-derived hepatic tissue possess MAPEG gene expression features, but not all protein expression could be detected, which helps to understand not only the nature of the tissue derived, but also the fate of bioartificial liver system, and may as well provide a valuable in vitro model for research in both inflammation process and toxic events in hepatological fields.

A novel reduction of diketones with i-RMgBr catalyzed by Cp2TiCl2 and deoxygenation of sulfoxides by Cp2TiCl2/Al system.

Alpha-diketones and beta-diketones react with Grignard reagents in the presence of a catalytic amount of Cp2TiCl2 to yield alpha-ketols and corresponding ketones respectively. Sulfoxides can be deoxygenated by Cp2TiCl2/Al system. The possible mechanisms are also discussed.