Facile Synthesis and Cytotoxicity of Phenazine-Chromene Hybrid Molecules Derived from Phenazine Natural Product.

AIM AND OBJECTIVE: Small molecule targeted drugs can effectively reduce the toxicity and side effects of drugs, and improve the efficacy of drugs by their specific antitumor activity. Hence, the development of small molecular targeted drugs for cancer has important significance. This study was undertaken to design and synthesize novel phenazine-chromene hybrid molecules in order to optimize the structure and improve the efficacy of this kind of hybrids. MATERIALS AND METHODS: O-diaminobenzene was used as starting material to synthesize twentyfour heterocyclic compounds designed as hybrid molecules of phenazine and 4H-chromene pharmacophores by facile methods. The structures of the compound were confirmed by 1H NMR, 13C NMR and HRMS. Furthermore, the synthesized compounds were evaluated for in vitro activity against four human cancer cell lines and two non-cancer cell lines by MTT test. RESULTS: Some compounds showed strong cytotoxic activities against HepG2 and A549 cancer lines (IC50 = 5-10 µM). Comparing 2i with 2l, the introduction of hydrophilic groups on the phenazine core could not improve the antiproliferative activity significantly. Except 2d and 3c, compounds owning chlorine substituent on the 4H-chromene pharmacophore seemingly contribute to enhance the compounds' antiproliferative activity. Specially, compound 3c showed highest cytotoxicity against A549 cells with IC50 values of 3.3±0.4 µM. Furthermore, all compounds showed low or no cytotoxicity against HUVEC and L02 non-cancer cells in vitro. CONCLUSION: Compound 3c may be used as potential lead molecule against A549 cancer cells.

Antibacterial sorbicillin and diketopiperazines from the endogenous fungus Penicillium sp. GD6 associated Chinese mangrove Bruguiera gymnorrhiza.

One new sorbicillin derivative, 2-deoxy-sohirnone C (1), one new diketopiperazine alkaloid, 5S-hydroxynorvaline-S-Ile (2), and two naturally occurring diketopiperazines, 3S-hydroxylcyclo(S-Pro-S-Phe) (3) and cyclo(S-Phe-S-Gln) (4), together with three known compounds were isolated from the Chinese mangrove endophytic fungus Penicillium sp. GD6. Their structures were determined on the basis of extensive spectroscopic analyses and by comparison with literature data. The absolute configuration of 3-hydroxyl moiety in 3 was determined by Mosher's method, while the absolute stereochemistry of 2 and 4 was established by comparison with the CD spectra of natural and synthesized diketopiperazines. Compound 1 showed moderate antibacterial activity against Methicillin-resistant Staphylococcus aureus with a MIC value of 80 µg·mL-1.

Cranberry extract supplementation exerts preventive effects through alleviating Aß toxicity in Caenorhabditis elegans model of Alzheimer's disease.

Cranberry extract (CBE) rich in polyphenols are potent to delay paralysis induced by alleviating ß-amyloid (Aß) toxicity in C. elegans model of Alzheimer's disease (AD). In order to better apply CBE as an anti-AD agent efficiently, we sought to deterrmine whether preventive or therapeutic effect contributes more prominently toward CBE's anti-AD activity. As the level of Aß toxicity and memory health are two major pathological parameters in AD, in the present study, we compared the effects of CBE on Aß toxicity and memory health in the C. elegans AD model treated with preventive and therapeutic protocols. Our results revealed that CBE prominently showed the preventive efficacy, providing a basis for further investigation of these effects in mammals.

Penibruguieramine A, a novel pyrrolizidine alkaloid from the endophytic fungus Penicillium sp. GD6 associated with Chinese mangrove Bruguiera gymnorrhiza.

A novel pyrrolizidine alkaloid, penibruguieramine A (1), characterized by an unprecedented 1-alkenyl-2-methyl-8-hydroxymethylpyrrolizidin-3-one skeleton, was isolated from the endophytic fungus Penicillium sp. GD6, associated with the Chinese mangrove Bruguiera gymnorrhiza. The absolute configuration of penibruguieramine A (1) was established by TDDFT ECD calculations of the vacuum and solution conformers, exploiting the transitions of the lactam chromophore. A plausible pathway for its biosynthesis has been proposed.

[Effect of environmental factors on the formation of several typical tetracycline resistance genes in soil].

The extensive use of veterinary tetracycline in the stock husbandry has led to the increasingly serious environmental pollution, the tetracycline resistance genes induced by which could bring more hazardous environmental risk than veterinary tetracycline. This study investigated the effects of environmental factors on the formation of several typical tetracycline resistance genes (tetA, tetC). The results showed that temperature, light and pH could have impacts on the formation of tetracycline resistance genes in soil, the amounts of the tetracycline resistance bacteria and resistance genes induced in different treatments all reached the maximum in the proper environmental condition (25 degrees C, 500 lx, pH7.5), which were all significantly higher than those in other environmental conditions (P < 0.05). In contrast, the adverse condition such as high temperature, strong light and high pH could effectively inhibit the formation of tetracycline resistance genes, probably due to the reduction of tetracycline residues or the direct influence on the formation of tetracycline resistance genes. And the results also showed that environmental factors could affect the growth of tetracycline resistance bacteria. Further analysis proved that the content of tetracycline resistance gene in soil had a positive correlation with the number of tetracycline resistance bacteria in the studied samples, therefore an inferred result was concluded that the growth of tetracycline resistance bacteria played a key role in the formation of the tetracycline resistance genes.

[Chemical constituents in the leave of Rhizophora stylosa L and their biological activities].

Ten compounds were isolated from the leaves of Rhizophora stylosa, one kind of mangrove plants distributed in the tropical and subtropical areas of the world. Their structures were identified as taraxerone (1), taraxerol (2), beta-sitosterol (3), careaborin (4), cis-careaborin (5), beta-daucosterol (6), isovanillic acid (7), protocatechuic acid (8), astilbin (9) and rutin (10), among which compound 9 and 10 were reported in this plant for the first time. Of these compounds, Compound 2 has been confirmed to have the abilities to inhibit the growth of Hela and BGC-823 with IC50 of 73.4 micromol x L(-1) and 73.3 micromol x L(-1), respectively. Compound 5 could inhibit the growth of BGC-823 and MCF-7 with IC50 of 45.9 micromol x L(-1) and 116.0 micromol x L(-1), respectively. Compound 9 and 10 were firstly reported to stimulate the proliferation of mice splenic lymphocytes markedly in a dose-dependent manner.

Molecular actions guiding neural regeneration in planarian.

Planarian is among the simplest animals that possess a centralized nervous system (CNS), and its neural regeneration involves the replacement of cells lost to normal 'wear and tear' (cell turnover), and/or injury. In this review, we state and discuss the recent studies on molecular control of neural regeneration in planarians. The spatial and temporal expression patterns of genes in intact and regenerating planarian CNS have already been described relatively clearly. The bone morphogenetic protein (BMP) and Wnt signaling pathways are identified to regulate neural regeneration. During neural regeneration, conserved axon guidance mechanisms are necessary for proper wiring of the nervous system. In addition, apoptosis may play an important role in controlling cell numbers, eliminating unnecessary tissues or cells and remodeling the old tissues for regenerating CNS. The bilateral symmetry is established by determination of anterior-posterior (A-P) and dorsal-ventral (D-V) patterns. Moreover, neurons positive to dopamine, serotonin (5-HT), and gamma-aminobutyric acid (GABA) have been detected in planarians. Therefore, planarians present us with new, experimentally accessible contexts to study the molecular actions guiding neural regeneration.

Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of hypothetical protein SCO4226 from Streptomyces coelicolor A3(2).

A non-Pfam hypothetical protein SCO4226 of molecular weight 9 kDa from Streptomyces coelicolor A3(2) was overexpressed in Escherichia coli and the purified recombinant protein was crystallized using the sitting-drop vapour-diffusion method. An X-ray diffraction data set was collected to 2.0 A resolution. The crystal belonged to space group P2(1), with unit-cell parameters a = 29.67, b = 67.00, c = 34.43 A, alpha = gamma = 90.00, beta = 94.26 degrees .

Evaluation of the long-term memory for thermosensation regulated by neuronal calcium sensor-1 in Caenorhabditis elegans.

OBJECTIVE: To evaluate whether the thermotaxis tracking model is suitable for assessing long-term memory (LTM) in the nematode Caenorhabditis elegans. METHODS: Animals were trained at 20 degrees C overnight in presence of food. The percentage of animals performing isothermal tracking (IT) behavior was measured at different time intervals after the training. RESULTS: The percentage of animals performing IT behavior, the numbers of body bends inside and outside the training temperature, and the expression patterns of AFD and AIY neurons were similar to those in control animals at 36 and 48 h after training; whereas when extending to 60, 72, and 84 h, locomotory behavior defects were observed in the assayed animals, suggesting that this thermal tracking model is feasible for analyzing LTM at 36 and 48 h after training. Moreover, the percentage of animals performing IT behavior was reduced at 18, 36, and 48 h after training in neuronal calcium sensor-1 gene (nsc-1) mutant animals compared with that in wild-type N2 animals. In addition, exposure to plumbum (Pb) significantly repressed the LTM at 18, 36, and 48 h after training in both wild-type N2 and ncs-1 mutant animals. CONCLUSION: The thermotaxis tracking model is suitable for evaluating the LTM regulated by NCS-1, and can be employed for elucidating regulatory functions of specific genes or effects of stimuli on memory in C. elegans.

Molecular control of memory in nematode Caenorhabditis elegans.

Model invertebrate organism Caenorhabditis elegans has become an ideal model to unravel the complex processes of memory. C. elegans has three simple forms of memory: memory for thermosensation, memory for chemosensation, and memory for mechanosensation. In the form of memory for mechanosensation, short-term memory, intermediate-term memory, and long-term memory have been extensively studied. The short-term memory and intermediate-term memory may occur in the presynaptic sensory neurons, whereas the long-term memory may occur in the postsynaptic interneurons. This review will discuss the recent progress on genetic and molecular regulation of memory in C. elegans.

Phenotypic and behavioral defects induced by iron exposure can be transferred to progeny in Caenorhabditis elegans.

OBJECTIVE: Previous work has showed that excess iron accumulation is harmful to reproduction and even promotes death; however, whether the multiple biological toxicity of iron (Fe) exposure could be transferred to progeny remains unknown. The present study used Caenorhabditis elegans to analyze the multiple toxicities of iron exposure and their possible transferable properties. METHODS: Three concentrations of iron sulfate solution (2.5 micromol/L, 75 micromol/L, and 200 micromol/L) were used. The endpoints of lifespan, body size, generation time, brood size, head thrash and body bend frequencies, and chemotaxis plasticity were selected to investigate Fe toxicity and its effect on progeny in Caenorhabditis elegans. RESULTS: The Fe toxicity could cause multiple biological defects in a dose-dependent manner by affecting different endpoints in nematodes. Most of the multiple biological defects and behavior toxicities could be transferred from Fe-exposed Caenorhabditis elegans to their progeny. Compared to the parents, no recovery phenotypes were observed for some of the defects in the progeny, such as body bend frequency and life span. We further summarized the defects caused by Fe exposure into 2 groups according to their transferable properties. CONCLUSION: Our results suggest that Fe exposure could cause multiple biological defects, and most of these severe defects could be transferred from Fe exposed nematodes to their progeny.

Computational analysis of genetic loci required for amphid structure and functions and their possibly corresponding microRNAs in C. elegans.

OBJECTIVE: To examine the important roles of microRNAs (miRNAs) in regulating amphid structure and function, we performed a computational analysis for the genetic loci required for the sensory perception and their possibly corresponding miRNAs in C. elegans. METHODS: Total 55 genetic loci required for the amphid structure and function were selected. Sequence alignment was combined with E value evaluation to investigate and identify the possible corresponding miRNAs. RESULTS: Total 30 genes among the 55 genetic loci selected have their possible corresponding regulatory miRNA (s), and identified genes participate in the regulation of almost all aspects of amphid structure and function. In addition, our data suggest that both the amphid structure and the amphid functions might be regulated by a series of network signaling pathways. Moreover, the distribution of miRNAs along the 3' untranslated region (UTR) of these 30 genes exhibits different patterns. CONCLUSION: We present the possible miRNA-mediated signaling pathways involved in the regulation of chemosensation and thermosensation by controlling the corresponding sensory neuron and interneuron functions. Our work will be useful for better understanding of the miRNA-mediated control of the chemotaxis and thermotaxis in C. elegans.

Learning and learning choice in the nematode Caenorhabditis elegans.

The nematode Caenorhabditis elegans is an attractive model organism to study the behavioral plasticity for its simple system and ability to respond to diverse environmental stimuli, such as touch, smell, taste and temperature. Learning in C. elegans encompasses both non-associative learning and associative learning. Till now, themotaxis and chemotaxis are two major paradigms for associative learning and there are at least 6 forms of chemotaxis-mediated associative learning. Three research systems have also been explored to study the mechanism of learning choice in worms. This review will discuss the forms, research models, genetic and molecular regulation of learning and learning choice in C. elegans.

[Protective effects of shark hepatic stimulator substance against acute hepatic injury induced by acetaminophen in mice].

AIM: To investigate the protective effects of shark hepatic stimulator substance (sHSS) against acute hepatic injury induced by acetaminophen (AAP) in mice. METHODS: Acute hepatic injury model of Balb/c mice was induced by a single intraperitoneal injection of AAP (200 mg.kg-1, i.p.). Serum ALT and AST activities were analyzed. The changes of microstructure and ultrastructure of hepatocyte were observed under optical and electronic microscope. The hepatocyte apoptosis was analyzed by flow cytometer and the expression level of Fas mRNA was determined by RT-PCR. RESULTS: The activities of serum ALT and AST were significantly decreased and both necrosis and inflammatory infiltration were improved in the mice treated with sHSS 3.0 and 1.5 mg.kg-1. sHSS (3.0 mg.kg-1) prevented the ultrastructural changes of hepatocytes caused by AAP, decreased the percentage of apoptotic cells, and downregulated the expression level of Fas mRNA. CONCLUSION: sHSS protected hepatocytes from AAP-induced injury, which might be associated with its protection of the mitochondria and inhibition of apoptosis and expression of Fas mRNA in hepatocytes.