Echinomycin, a member of the quinoxaline family of antibiotics, is known to be a small-molecule inhibitor of hypoxia inducible factor-1 (HIF-1) DNA binding activity. Recently, it has been shown to suppress mammalian target of rapamycin (mTOR) signaling and growth in leukemia cell lines. In this study, we investigated whether echinomycin interacts with the FKBP12 protein. Molecular docking was used, and the predicted binding energy was -10.61 kcal/mol. Moreover, surface plasmon resonance imaging and fluorescence quenching techniques were used to validate this interaction. Echinomycin binds to FKBP12 with a strong binding affinity comparable with rapamycin. Furthermore, the echinomycin-FKBP12 complex has been shown to affect calcineurin activity when tested in a calcineurin phosphatase inhibition assay. All of these studies have shown that echinomycin may have a double impact on HIF signaling by direct inhibition and through mTOR.
A CFD scheme was presented for modeling municipal solid waste (MSW) combustion in a moving-grate incinerator, including the in-bed burning of solid wastes, the out-of-bed burnout of gaseous volatiles, and the selective non-catalytic reduction (SNCR) process between urea (CO(NH2)2) and NOx. The in-bed calculations provided 2-D profiles of the gas-solid temperatures and the gas species concentrations along the bed length, which were then used as inlet conditions for the out-of-bed computations. The over-bed simulations provided the profiles of incident radiation heat flux on the top of bed. A 3-dimensional benchmark simulation was conducted with a 750 t/day commercial incinerator using the present coupling scheme incorporating with a reduced SNCR reduction mechanism. Numerical tests were performed to investigate the effects of operating parameters such as injection position, injection speed and the normalized stoichiometric ratio (NSR) on the SNCR performance. The simulation results showed that the distributions of gas velocity, temperature and NOx concentration were highly non-uniform, which made the injection position one of the most sensitive operating parameters influencing the SNCR performance of moving grate incinerators. The simulation results also showed that multi-layer injections were needed to meet the EU2000 standard, and a NSR 1.5 was suggested as a compromise of a satisfactory NOx reduction and reasonable NH3 slip rates. This work provided useful guides to the design and operation of SNCR process in moving-grate incinerators.
The high mutation rate of RNA viruses has resulted in limitation of vaccine effectiveness and increased emergence of drug-resistant viruses. New effective antivirals are therefore needed to control of the highly mutative RNA viruses. The n-butanol fraction of the stem bark of Mangifera indica exhibited inhibitory activity against influenza neuraminidase (NA) and coxsackie virus 3C protease. Bioassay guided phytochemical study of M. indica stem bark afforded two new compounds including one benzophenone C-glycoside (4) and one xanthone dimer (7), together with eleven known compounds. The structures of these isolated compounds were elucidated on the basis of spectroscopic evidences and correlated with known compounds. Anti-influenza and anti-coxsackie virus activities were evaluated by determining the inhibition of anti-influenza neuraminidase (NA) from pandemic A/RI/5+/1957 H2N2 influenza A virus and inhibition of coxsackie B3 virus 3C protease, respectively. The highest anti-influenza activity was observed for compounds 8 and 9 with IC50 values of 11.9 and 9.2?M, respectively. Compounds 8 and 9 were even more potent against coxsackie B3 virus 3C protease, with IC50 values of 1.1 and 2.0?M, respectively. Compounds 8 and 9 showed weak cytotoxic effect against human hepatocellular carcinoma and human epithelial carcinoma cell lines through MTT assay.
During the systematic screening of active compounds from marine-derived fungi, the extract of a strain of Aspergillus versicolor MF359 isolated from a marine sponge of Hymeniacidon perleve was identified for detailed chemical investigation. Three new secondary metabolites, named hemiacetal sterigmatocystin (1), acyl-hemiacetal sterigmatocystin (2), and 5-methoxydihydrosterigmatocystin (3), together with a known compound, aversin (4), were characterized. 1 represents a first structure of sterigmatocystin hemiacetal from nature. The antibacterial activities of these identified compounds were evaluated against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa. Compound 3 showed activity against S. aureus and B. subtilis with MIC values of 12.5 and 3.125 ?g/mL, respectively.
Although the pathogenetic mechanisms driving Alzheimer's disease (AD) are unclear, genetic variations may play an important role. Previous studies have identified that single nucleotide polymorphisms (SNPs) in the sortilin-related receptor, L (DLR class) A repeats containing (SORL1) gene are associated with AD or amnestic mild cognitive impairment (aMCI) patients. However, the association of SORL1 variants with AD or aMCI susceptibility in the Han Chinese population has not been adequately reported. Thus, we conducted a case-control study in 106 sporadic AD patients, 67 aMCI patients, and 179 healthy control Han Chinese subjects to determine whether SORL1 genetic variations alter the risk for AD or aMCI. Using the LDR-PCR method to genotype five polymorphisms in SORL1, we found significant associations (for AD: OR=1.968, 95% CI=1.273-3.042; for aMCI: OR=2.210, 95% CI=1.353-3.610) between the 'A' allele of the SORL1 SNP rs985421 and AD and aMCI, which may represent an ApoE ?4-independent risk factor for SAD. These findings suggest that the SORL1 SNP rs985421 may alter the risk for sporadic AD and aMCI in the Han Chinese population.
A high-throughput screening of a microbial natural product library led to the discovery of two novel compounds named nivetetracyclates A and B (1 and 2), which were produced by Streptomyces niveus designated as LS2151. The backbone of the compounds contains a hydrotetracyclate not previously reported from a natural source. The structures of the compounds were elucidated by spectroscopic methods. The nivetetracyclates exhibited activity against human HeLa cells.
As part of a search for antitubercular substances from natural sources, we screened a library of endophytic microbes (50 strains and 300 crude extracts in total) isolated from traditional Chinese medicines (TCMs) for growth inhibitory activity against Bacillus Calmette-Guérin (BCG). The crude extract of Streptomyces sp. strain Y3111, which was associated with the stems of Heracleum souliei, showed good anti-BCG activity with an MIC value of 12.5 ?g/mL. Bioassay-guided isolation led to four new pluramycin-type compounds, heraclemycins A-D (1-4). Their structures were determined by different spectroscopic techniques including HRMSESI, 1D NMR, and 2D NMR. This is the first report of pluramycin analogues produced by TCM endophytic microbes as well as the first example of BCG-selective pluramycins. Heraclemycin C (3) showed selective antitubercular activity against BCG with a MIC value of 6.25 ?g/mL and a potential new mode of action.
In the course of a screening program for bioactive compounds from a marine natural product library, a newly isolated Actinomycetes strain, designated as MS100061, exhibited strong anti-Mycobacterium bovis Bacillus Calmette-Guérin (BCG) activity. The strain belongs to the genus Streptomyces according to its morphological and 16S rDNA phylogenetic analysis. Bioassay-guided isolation resulted in a new spirotetronate, lobophorin G (1), together with two known compounds, lobophorins A (2) and B (3). The structures were elucidated by extensive spectroscopic methods and comparison with literatures. Compounds 1-3 were subjected to anti-BCG, antituberculosis, and antibacterial screening and exhibited potent anti-BCG activity with minimum inhibitory concentration (MIC) values of 1.56, 1.56, and 0.78 ?g/ml, respectively, and moderate anti-Mycobacterium tuberculosis H37Rv activity with MIC values of 32, 32, and 16 ?g/ml, respectively. The MIC values of compounds 1-3 against Bacillus subtilis were 3.125, 12.5, and 1.56 ?g/ml, respectively, indicating great potential for antibacterial drugs. In addition, this is the first report of the anti-BCG and antituberculosis activities of lobophorins.
Inflammation is a primary event in atherogenesis. Oleoylethanolamide (OEA), a naturally occurring fatty-acid ethanolamide, lowers lipid levels in liver and blood through activation of the nuclear receptor, peroxisome proliferator-activated receptor-alpha (PPAR?). We designed and synthesized (Z)-(S)-9-octadecenamide, N-(2-hydroxyethyl, 1-methyl) (OPA), an OEA analog. The present study investigated the effect of OPA on the expression of adhesion molecules in human umbilical vein endothelial cells (HUVEC). OPA inhibited expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) stimulated by Tumor Necrosis Factor-? (TNF-?) via activation of PPAR?. This inhibition of VCAM-1 and ICAM-1 expression decreased adhesion of monocyte-like cells to stimulated endothelial cells. These results demonstrate that OPA may have anti-inflammatory properties. Our results thus provide new insights into possible future therapeutic approaches to the treatment of atherosclerosis.
The new secondary metabolites verrucosidinol (1) and its derivative verrucosidinol acetate (2), together with a potent neurotoxin verrucosidin (3), a congener norverrucosidin (4) and a mixture of two known phytotoxic metabolites terrestric acids (5 and 6), were isolated from the marine derived fungus Penicillium aurantiogriseum. Verrucosidinol has a ring-opened ethylene oxide moiety in the polyene ?-pyrone skeleton, and verrucosidinol acetate is its acetate derivative. The chemical structures were determined by comparing with literature data and a combination of spectroscopic techniques, including high resolution mass spectrum and two-dimentional nuclear magnetic resonance spectroscopic analysis.
NC0604, the new antibiotic of the bleomycin family, was isolated from the fermentation broth of Streptomyces verticillus var. pingyangensis n.sp. In this study, we investigated its mechanisms of antitumor action in vitro and in vivo. The results showed that the colony formation inhibition of NC0604 was 2-10 times higher than that of bleomycin to several tumor cell types. In comparison to bleomycin, a better antitumor efficacy of NC0604 was observed in the BALB/c mice loading mouse hepatoma H22 tumors. Flow cytometry assay detected an increase of intracellular reactive oxygen species and arrest at G2/M phase in human hepatoma HepG2 cells after exposure to NC0604. The comet of DNA damage was also observed in the NC0604-treated cells using single cell gel electrophoresis assay. The chromatin condensation appeared in the NC0604-induced apoptotic cells. The activation of apoptotic caspase pathway and increase of apoptosis-modulated protein expression, such as p53, Bax, were also detected by Western blot analysis. Taken together, the anti-tumor actions of NC0604 involve activation of the apoptotic pathway and it is valuable for further drug development.
Five new polyketide derivatives, 7-O-methylkoninginin D (1) and trichodermaketones A-D (2-5), together with four known compounds, koninginins A, D, E, and F, were isolated from the marine-derived fungus Trichoderma koningii. Trichodermaketones A (2) and B (3) are unprecedented polyketides with a bistetrafuran-containing tricyclic skeleton. The chemical structures and absolute configurations of compounds 1-5 were elucidated by comparing with literature data and extensive spectroscopic methods, including 2D NMR and CD spectroscopic analysis. Compounds 1-5 were evaluated for action against bacteria and fungi and for synergistic antifungal activity. Compound 2 showed synergistic antifungal activity against Candida albicans with 0.05 microg/mL ketoconazole.
Despite impressive results obtained in animal models, the clinical use of Fas ligand (FasL) as an anticancer drug is limited by severe toxicity. Systemic toxicity of death ligands may be prevented by using genes encoding membrane-bound death ligands and by targeted transgene expression through either targeted transduction or targeted transcription. Selective induction of tumor cell death is a promising anticancer strategy. A fusion protein is created by fusing the extracellular domain of Fas ligand (FasL) to the peptide arginine-glycine-aspartic acid (RGD) that selectively targets avbeta3-integrins on tumor endothelial cells. The purpose of this study is to evaluate the effects of RGD-FasL on tumor growth and survival in a murine hepatocellular carcinoma (HCC) tumor model. Treatment with RGD-FasL displaying an obvious suppressive effect on the HCC tumor model as compared to that with FasL (p < 0.05) and resulted in a more additive effect on tumor growth delay in this model. RGD-FasL treatment significantly enhanced mouse survival and caused no toxic effect, such as weight loss, organ failure, or other treatment-related toxicities. Apoptosis was detected by flow cytometric analysis and TUNEL assays; those results also showed that RGD-FasL is a more potent inducer of cell apoptosis for H22 and H9101 cell lines than FasL (p <0.05). In conclusion, RGD-FasL appears to be a low-toxicity selective inducer of tumor cell death, which merits further investigation in preclinical and clinical studies. Furthermore, this approach offers a versatile technology for complexing target ligands with therapeutic recombinant proteins. To distinguish the anti-tumor effects of FasL in vivo, tumor and liver tissues were harvested to examine for evidence of necrotic cells, tumor cells, or apoptotic cells by Hematoxylin and eosin (HE) staining.
The prognosis of hepatocellular carcinoma (HCC) is poor, even with the combined treatment of curative resection and adjuvant chemoradiotherapy. To solve this problem, many biologic therapies have been investigated. Fas ligand (FasL, CD95L) is mainly expressed in activated T lymphocytes and natural killer (NK) cells, and plays a central role in both cell-mediated immunity and immune downregulation. Several studies have shown that FasL is expressed in HCC. In the present report, we prepared recombinant human pET-22b(+)/FasL protein and investigated the effect of FasL on HCC cells in vitro and on tumor growth in a murine HCC tumor model. The well-known cytotoxic chemotherapeutic reagent adriamycin (ADM) served as a control. We found that FasL effectively suppressed the viability of H22 tumor cells and significantly induced the apoptosis of H22 cells. The apoptotic levels of cells treated with FasL-ADM were significantly higher than those treated with FasL or ADM alone, and the FasL-ADM combination resulted in a more than additive effect on tumor growth delay in this model. The results suggested that combined treatment of FasL and other chemotherapeutic agents may be a new approach to improve the efficacy of chemotherapy for HCC.
An Aspergillus versicolor isolated from sediment collected from the Bohai Sea, China, yielded the new dimeric diketopiperazine brevianamide S (1), together with three new monomeric cometabolites, brevianamides T (2), U (3), and V (4). Structures were determined by detailed spectroscopic analysis. Brevianamide S exhibited selective antibacterial activity against Bacille Calmette-Guérin (BCG), suggestive of a new mechanism of action that could inform the development of next-generation antitubercular drugs.
Three new alkaloids, including auranomides A and B (1 and 2), a new scaffold containing quinazolin-4-one substituted with a pyrrolidin-2-iminium moiety, and auranomide C (3), as well as two known metabolites auranthine (4) and aurantiomides C (5) were isolated from the marine-derived fungus Penicillium aurantiogriseum. The chemical structures of compounds 1-3 were elucidated by extensive spectroscopic methods, including IR, HRESIMS and 2D NMR spectroscopic analysis. The absolute configurations of compounds 1-3 were suggested from the perspective of a plausible biosynthesis pathway. Compounds 1-3 were subjected to antitumor and antimicrobial screening models. Auranomides A-C exhibited moderate cytotoxic activity against human tumor cells. Auranomides B was the most potent among them with an IC(50) value of 0.097 ?mol/mL against HEPG2 cells.
Multidrug-resistant tuberculosis (MDR-TB) and TB-HIV co-infection have become a great threat to global health. However, the last truly novel drug that was approved for the treatment of TB was discovered 40 years ago. The search for new effective drugs against TB has never been more intensive. Natural products derived from microbes and medicinal plants have been an important source of TB therapeutics. Recent advances have been made to accelerate the discovery rate of novel TB drugs including diversifying strategies for environmental strains, high-throughput screening (HTS) assays, and chemical diversity. This review will discuss the challenges of finding novel natural products with anti-TB activity from marine microbes and plant medicines, including biodiversity- and taxonomy-guided microbial natural products library construction, target- and cell-based HTS, and bioassay-directed isolation of anti-TB substances from traditional medicines.
In Pseudomonas aeruginosa, the quorum-sensing (QS) system is closely related to biofilm formation. We previously demonstrated that 14-alpha-lipoyl andrographolide (AL-1) has synergistic effects on antibiofilm and antivirulence factors (pyocyanin and exopolysaccharide) of P. aeruginosa when combined with conventional antibiotics, while it has little inhibitory effect on its growth. However, its molecular mechanism remains elusive. Here we investigated the effect of AL-1 on QS systems, especially the Las and Rhl systems. This investigation showed that AL-1 can inhibit LasR-3-oxo-C(12)-homoserine lactone (HSL) interactions and repress the transcriptional level of QS-regulated genes. Reverse transcription (RT)-PCR data showed that AL-1 significantly reduced the expression levels of lasR, lasI, rhlR, and rhlI in a dose-dependent manner. AL-1 not only decreased the expression level of Psl, which is positively regulated by the Las system, but also increased the level of secretion of ExoS, which is negatively regulated by the Rhl system, indicating that AL-1 has multiple effects on both the Las and Rhl systems. It is no wonder that AL-1 showed synergistic effects with other antimicrobial agents in the treatment of P. aeruginosa infections.
We report the isolation of Pi1, a gene conferring broad-spectrum resistance to rice blast (Magnaporthe oryzae). Using loss- and gain-of-function approaches, we demonstrate that Pi1 is an allele at the Pik locus. Like other alleles at this locus, Pi1 consists of two genes. A functional nucleotide polymorphism (FNP) was identified that allows differentiation of Pi1 from other Pik alleles and other non-Pik genes. A extensive germplasm survey using this FNP reveals that Pi1 is a rare allele in germplasm collections and one that has conferred durable resistance to a broad spectrum of pathogen isolates.
In the course of our screening program for anti-Mycobacterium bovis bacillus Calmette-Guérin (BCG) and anti-Mycobacterium tuberculosis H37Rv (MTB H37Rv) agents from our marine natural product library, a newly isolated actinomycete strain, designated as MS449, was picked out for further investigation. The strain MS449, isolated from a sediment sample collected from South China Sea, produced actinomycin X(2) and actinomycin D in substantial quantities, which showed strong inhibition of BCG and MTB H37Rv. The structures of actinomycins were elucidated by nuclear magnetic resonance and mass spectrometric analysis. The strain MS449 was taxonomically characterized on the basis of morphological and phenotypic characteristics, genotypic data, and phylogenetic analysis. The 16S rRNA gene sequence of the strain was determined and a database search indicated that the strain was closely associated with the type strain of Streptomyces avermitilis (99.7 % 16S rRNA gene similarity). S. avermitilis has not been previously reported to produce actinomycins. The marine-derived strain of Streptomyces sp. MS449 produced notably higher quantities of actinomycin X(2) (1.92 mg/ml) and actinomycin D (1.77 mg/ml) than previously reported actinomycins producing strains. Thus, MS449 was considered of great potential as a new industrial producing strain of actinomycin X(2) and actinomycin D.
Oleoylethanolamide (OEA) is a high-affinity agonist of peroxisome proliferator-activated receptor ? (PPAR?) which may act as an endogenous neuroprotective factor. However, it is not clear whether orally administered OEA is effective against ischemic brain injury. In our study, transient focal cerebral ischemia was induced by middle cerebral artery occlusion for 90 min followed by reperfusion. To evaluate its preventive effects, OEA (10, 20 or 40 mg/kg, ig) was administered for 3 days before ischemia. To evaluate its therapeutic effects, OEA (40 mg/kg, ig) was administered at 0.5 or 1h before reperfusion or at 0 or 1h after reperfusion. In some experiments, the PPAR? antagonist MK886 (10mg/kg, ig) was administered 0.5h before OEA. Neurological deficit score, infarct volume and brain edema degree were determined at 24h after reperfusion. Blood-brain barrier (BBB) disruption was evaluated by Evans blue (EB) leakage at 6h after reperfusion. Real-time RT-PCR and western blot were performed to detect PPAR? mRNA and protein expression. Oral OEA pretreatment improved neurological dysfunction reduced infarct volume and alleviated brain edema in a dose-dependent manner; the most effective dose was 40 mg/kg. The therapeutic time is within 1h after reperfusion. OEA also increased PPAR? mRNA and protein expression in the ischemic brain. The PPAR? antagonist MK886 abolished the protective effects of OEA. In conclusion, our results indicate that orally administered OEA protects against acute cerebral ischemic injury in mice, at least in part by activating PPAR?.
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