Two New 4-Hydroxy-2-pyridone Alkaloids with Antimicrobial and Cytotoxic Activities from Arthrinium sp. GZWMJZ-606 Endophytic with Houttuynia cordata Thunb.

Two new 4-hydroxy-2-pyridone alkaloids furanpydone A and B (1 and 2), along with two known compounds N-hydroxyapiosporamide (3) and apiosporamide (4) were isolated from the endophytic fungus Arthrinium sp. GZWMJZ-606 in Houttuynia cordata Thunb. Furanpydone A and B had unusual 5-(7-oxabicyclo[2.2.1]heptane)-4-hydroxy-2-pyridone skeleton. Their structures including absolute configurations were determined on the basis of spectroscopic analysis, as well as the X-ray diffraction experiment. Compound 1 showed inhibitory activity against ten cancer cell lines (MKN-45, HCT116, K562, A549, DU145, SF126, A-375, 786O, 5637, and PATU8988T) with IC50 values from 4.35 to 9.72 µM. Compounds 1, 3 and 4 showed moderate inhibitory effects against four Gram-positive strains (Staphylococcus aureus, methicillin-resistant S. aureus, Bacillus Subtilis, Clostridium perfringens) and one Gram-negative strain (Ralstonia solanacarum) with MIC values from 1.56 to 25 µM. However, compounds 1-4 showed no obvious inhibitory activity against two Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and two pathogenic fungi (Candida albicans and Candida glabrata) at 50 µM. These results show that compounds 1-4 are expected to be developed as lead compounds for antibacterial or anti-tumor drugs.

Indole Diterpene Derivatives from the Aspergillus flavus GZWMJZ-288, an Endophytic Fungus from Garcinia multiflora.

A new indole diterpene, 26-dihydroxyaflavininyl acetate (1), along with five known analogs (2-6) were isolated from the liquid fermentation of Aspergillus flavus GZWMJZ-288, an endophyte from Garcinia multiflora. The structures of these compounds were identified through NMR, MS, chemical reaction, and X-ray diffraction experiments. Enzyme inhibition activity screening found that compounds 1, 4, and 6 have a good binding affinity with NPC1L1, among which compound 6 exhibited a stronger binding ability than ezetimibe at a concentration of 10 µM. Moreover, compound 5 showed inhibitory activity against α-glucosidase with an IC50 value of 29.22 ± 0.83 µM, which is 13 times stronger than that of acarbose. The results suggest that these aflavinine analogs may serve as lead compounds for the development of drugs targeting NPC1L1 and α-glucosidase. The binding modes of the bioactive compounds with NPC1L1 and α-glucosidase were also performed through in silico docking studies.

The role of hexose transporter-like sensor hxs1 and transcription activator involved in carbohydrate sensing azf1 in xylose and glucose fermentation in the thermotolerant yeast Ogataea polymorpha.

BACKGROUND: Fuel ethanol from lignocellulose could be important source of renewable energy. However, to make the process feasible, more efficient microbial fermentation of pentose sugars, mainly xylose, should be achieved. The native xylose-fermenting thermotolerant yeast Ogataea polymorpha is a promising organism for further development. Efficacy of xylose alcoholic fermentation by O. polymorpha was significantly improved by metabolic engineering. Still, genes involved in regulation of xylose fermentation are insufficiently studied. RESULTS: We isolated an insertional mutant of O. polymorpha with impaired ethanol production from xylose. The insertion occurred in the gene HXS1 that encodes hexose transporter-like sensor, a close homolog of Saccharomyces cerevisiae sensors Snf3 and Rgt2. The role of this gene in xylose utilization and fermentation was not previously elucidated. We additionally analyzed O. polymorpha strains with the deletion and overexpression of the corresponding gene. Strains with deletion of the HXS1 gene had slower rate of glucose and xylose consumption and produced 4 times less ethanol than the wild-type strain, whereas overexpression of HXS1 led to 10% increase of ethanol production from glucose and more than 2 times increase of ethanol production from xylose. We also constructed strains of O. polymorpha with overexpression of the gene AZF1 homologous to S. cerevisiae AZF1 gene which encodes transcription activator involved in carbohydrate sensing. Such transformants produced 10% more ethanol in glucose medium and 2.4 times more ethanol in xylose medium. Besides, we deleted the AZF1 gene in O. polymorpha. Ethanol accumulation in xylose and glucose media in such deletion strains dropped 1.5 and 1.8 times respectively. Overexpression of the HXS1 and AZF1 genes was also obtained in the advanced ethanol producer from xylose. The corresponding strains were characterized by 20-40% elevated ethanol accumulation in xylose medium. To understand underlying mechanisms of the observed phenotypes, specific enzymatic activities were evaluated in the isolated recombinant strains. CONCLUSIONS: This paper shows the important role of hexose sensor Hxs1 and transcription factor Azf1 in xylose and glucose alcoholic fermentation in the native xylose-fermenting yeast O. polymorpha and suggests potential importance of the corresponding genes for construction of the advanced ethanol producers from the major sugars of lignocellulose.

Sulfur-Containing Phenolic Compounds from the Cave Soil-Derived Aspergillus fumigatus GZWMJZ-152.

Six new sulfur-containing phenolic compounds (1-6) and their putative metabolic precursors (7-9) were isolated from the cave soil-derived fungus Aspergillus fumigatus GZWMJZ-152. Compound 1 represents an unusual benzophenone-diketopiperazine hybrid via a thioether linker, while compound 2 contains a naturally rare sulfoxide group. Both compounds 2 and 3 were initially isolated as racemic mixtures and then purified as the enantiomerically pure (+)-2, (-)-2, (+)-3, and (-)-3, respectively. Their structures, including absolute configurations, were elucidated by spectroscopic analysis, X-ray diffraction, and the calculations of electronic circular dichroism. The antioxidant activity of compounds 1-9 was evaluated based on oxygen radical absorbance capacity, 2,2-diphenyl-1-picrylhydrazyl radical scavenging, and the protective effect on the PC12 cell line against H2O2-induced damage. Compounds 5-7 and 9 showed radical-scavenging activity against 2,2-diphenyl-1-picrylhydrazyl free radicals with the IC50 values of 3.45 ± 0.02, 23.73 ± 0.08, 18.90 ± 0.16, and 17.27 ± 0.15 µM, respectively. Compounds (±)-2, 4, 7, and 8 exhibited potent antioxidant capacity with oxygen radical absorbance capacity values of 1.73 ± 0.13, 1.65 ± 0.03, 6.14 ± 0.35, and 1.55 ± 0.04 µmol TE/µmol, respectively. Compounds (±)-2 and (±)-3 also exhibited protective effects on oxidative injury of PC12 cells induced by H2O2.

Development of new dominant selectable markers for the nonconventional yeasts Ogataea polymorpha and Candida famata.

Nonconventional yeast Candida famata and Ogataea polymorpha are interesting organisms for basic and applied studies. O. polymorpha is methylotrophic thermotolerant yeast capable of xylose alcoholic fermentation whereas C. famata is capable of riboflavin overproduction. Still, the new tools for molecular research of these species are needed. The aim of this study was to develop the new dominant selective markers for C. famata and O. polymorpha usable in metabolic engineering experiments. In this work, the BSD gene from Aspergillus terreus coding for blasticidin S deaminase, O. polymorpha AUR1 gene required for sphingolipid synthesis and IMH3 gene, which encodes IMP dehydrogenase, were tested as the new dominant selective marker genes. Our results showed that AUR1 and IMH3 genes could be used as dominant selective markers for O. polymorpha with frequencies of transformation of 40 and 20 transformants per microgram of DNA, respectively. The IMH3 gene was successfully used as the marker for construction of O. polymorpha strains with increased ethanol production from xylose due to overexpression of TAL1, TKL1 and AOX1 genes. The BSD gene from A. terreus, conferring resistance to blasticidin, was found to be efficient for selection of C. famata transformants.

Semisynthetic Derivatives of Fradcarbazole A and Their Cytotoxicity against Acute Myeloid Leukemia Cell Lines.

Fourteen derivatives of the marine-derived fradcarbazole A were synthesized from staurosporine. Their structures were identified by NMR and high-resolution electrospray ionization mass spectrometry (HRESIMS). The derivatives were screened in vitro for antiproliferative activity against three human leukemic cell lines (MV4-11, HL-60, K562). All of the derivatives displayed cytotoxicity against the human FLT-3 internal tandem duplication (ITD) mutant acute myeloid leukemia (AML) cell line MV4-11 with IC50 values of 0.32-0.96 µM. The mechanism of action studies indicated that the most effective 3-chloro-5‴-fluorofradcarbazole A (6) induced apoptosis of the MV4-11 cells and arrested the cell cycle at the G0/G1 phase. Furthermore, compound 6 can reduce the expression of FLT-3, CDK2, and c-kit. The results suggest that 3-chloro-5‴-fluorofradcarbazole A (6) is a potential candidate for developing novel anti-AML agents in the future.

Proteomic analysis of the influence of Cu(2+) on the crystal protein production of Bacillus thuringiensis X022.

BACKGROUND: Bacillus thuringiensis X022, a novel strain isolated from soil in China, produces diamond-shaped parasporal crystals. Specific mineral nutrients, such as Mg, Cu, and Mn, influence insecticidal crystal proteins (ICP) expression and the effects of these elements vary significantly. However, the molecular mechanisms of the effects caused by mineral elements have yet to be reported. RESULTS: The ICP are mainly composed of Cry1Ca, Cry1Ac, and Cry1Da, which have molecular weights of about 130 kDa. ICP production was most efficient when Cu(2+) was added at concentrations ranging from 10(-6) to 10(-4) mol/L at an initial pH of 8.0. Addition of Cu(2+) also evidently increased the toxicity of fermentation broth to Spodoptera exigua and Helicoverpa armigera. After analyzing changes in proteome and fermentation parameters caused by Cu(2+) addition, we propose that Cu(2+) increases PhaR expression and consequently changes the carbon flow. More carbon sources was used to produce intracellular poly-ß-hydroxybutyrate (PHB). Increases in PHB as a storage material bring about increases of ICP production. CONCLUSIONS: Bacillus thuringiensis X022 mainly expresses Cry1Ca, Cry1Ac, and Cry1Da. Cu(2+) increases the expression of Cry1Da, Cry1Ca, and also enhances the toxicity of fermentation broth to S. exigua and H. armigera.

Detection of toxin proteins from Bacillus thuringiensis strain 4.0718 by strategy of 2D-LC-MS/MS.

Bacillus thuringiensis is a kind of insecticidal microorganism which can produce a variety of toxin proteins, it is particularly important to find an effective strategy to identify novel toxin proteins rapidly and comprehensively with the discovery of the wild-type strains. Multi-dimensional high-performance liquid chromatography combined with mass spectrometry has become one of the main methods to detect and identify toxin proteins and proteome of B. thuringiensis. In this study, protein samples from B. thuringiensis strain 4.0718 were analyzed on the basis of two-dimensional liquid chromatography-tandem mass spectrometry (2D-LC-MS/MS), and tryptic peptides of whole cell from the late sporulation phase were eluted at different concentration gradients of ammonium chloride and followed by secondary mass spectrum identification. 831 and 894 proteins were identified from two biological replicates, respectively, while 1,770 and 1,859 peptides were detected correspondingly. Among the identified proteins and peptides, 606 proteins and 1,259 peptides were detected in both replicates, which mean that 1,119 proteins and 2,370 peptides were unique to the proteome of this strain. A total of 15 toxins have been identified successfully, and seven of them were firstly discovered in B. thuringiensis strain 4.0718 that were Crystal protein (A1E259), pesticidal protein (U5KS09), Cry2Af1 (A4GVF0), Cry2Ad (Q9RM89), Cry1 (K4HMB5), Cry1Bc (Q45774), and Cry1Ga (Q45746). The proteomic strategy employed in the present study has provided quick and exhaustive identification of toxins produced by B. thuringiensis.

[Screening and antibacterial function of Bacillus amyloliquefaciens X030].

OBJECTIVE: We isolated 339 bacillus strains from 72 soil samples all over the country, then purified their antimicrobial compounds and studied the antibacterial activity, to enrich bacillus resources and explore their second metabolites. METHODS: A bacillus strain with strong antibacterial activity was selected by dilution plate and water bath heating from a soil sample from a peanut plantation in Henan Province; this strain was identified according to morphological observation, physiological and biochemical characteristics, and consequences of 16S rRNA homologous analysis. Antibacterial compound from the identified strain, Bacillus amyloliquefaciens X030, was separated and purified by acetone precipitation, Sephadex chromatography, C18 reverse phase column chromatography. Its molecular weight was analyzed by LC-MS/MS. The antibacterial activity was characterized by disc diffusion and plate two-way cultivation. RESULTS: Bacillus amyloliquefaciens was isolated that not only has antibacterial activity against Staphylococcus aureus, Candida albican and Saccharomycetes; but also against Pyriculariaoryzae, Chili pointed cell anthrax, Gloeosporium eriobotryae speg and Phytophthora parasitica. The compound was confirmed as polypeptide. CONCLUSION: Bacillus amyloliquefaciens X030 can produce a polypeptide that inhibits pathogenic bacteria and plant pathogenic fungi.

Five previously undescribed citrinin derivatives from the endophytic fungus Penicillium citrinum GZWMJZ-836.

Penicillium citrinum GZWMJZ-836 is an endophytic fungus from Drynaria roosii Nakaike. Five previously undescribed citrinin derivatives (1-5) and six intermediates related to their biosynthesis (6-11) were obtained from the extract of this strain's solid fermentation using multiple column chromatography separations, including high-performance liquid chromatography. The structures of these compounds were determined through comprehensive spectroscopic analyses, primarily using NMR and HRESIMS data. The stereochemistry was mainly confirmed by ECD calculations, and the configurations of C-7' in compounds 4 and 5 were determined using 13C NMR calculations. Compounds 4-5 and 8 showed antibacterial activity against five strains, with minimum inhibitory concentration values ranging from 7.8 to 125 µM. Compounds 4 and 7 exhibited inhibitions against three plant pathogenic fungi, with IC50 values ranging from 66.6 to 152.1 µM. Additionally, a putative biosynthetic pathway for compounds 1-5 derived from citrinin was proposed.

MAP65-1a positively regulates H2O2 amplification and enhances brassinosteroid-induced antioxidant defence in maize.

Brassinosteroid (BR)-induced antioxidant defence has been shown to enhance stress tolerance. In this study, the role of the maize 65 kDa microtubule-associated protein (MAP65), ZmMAP65-1a, in BR-induced antioxidant defence was investigated. Treatment with BR increased the expression of ZmMAP65-1a in maize (Zea mays) leaves and mesophyll protoplasts. Transient expression and RNA interference silencing of ZmMAP65-1a in mesophyll protoplasts further revealed that ZmMAP65-1a is required for the BR-induced increase in expression and activity of superoxide dismutase (SOD) and ascorbate peroxidase (APX). Both exogenous and BR-induced endogenous H2O2 increased the expression of ZmMAP65-1a. Conversely, transient expression of ZmMAP65-1a in maize mesophyll protoplasts enhanced BR-induced H2O2 accumulation, while transient silencing of ZmMAP65-1a blocked the BR-induced expression of NADPH oxidase genes and inhibited BR-induced H2O2 accumulation. Inhibiting the activity and gene expression of ZmMPK5 significantly prevented the BR-induced expression of ZmMAP65-1a. Likewise, transient expression of ZmMPK5 enhanced BR-induced activities of the antioxidant defence enzymes SOD and APX in a ZmMAP65- 1a-dependent manner. ZmMPK5 directly interacted with ZmMAP65-1a in vivo and phosphorylated ZmMAP65-1a in vitro. These results suggest that BR-induced antioxidant defence in maize operates through the interaction of ZmMPK5 with ZmMAP65-1a. Furthermore, ZmMAP65-1a functions in H2O2 self-propagation via regulation of the expression of NADPH oxidase genes in BR signalling.

Cytotoxic Indolyl Diketopiperazines from the Aspergillus sp. GZWMJZ-258, Endophytic with the Medicinal and Edible Plant Garcinia multiflora.

Two new indolyl diketopiperazines, gartryprostatins A and B (1 and 2), with an unusual 2,3-furan-fused pyrano[2,3-g]pyrrolo[1″,2″:4',5']pyrazino[1',2':1,5]pyrrolo[2,3-b]indole nucleus, along with a new naturally occurring compound (gartryprostatin C, 3) were isolated from the solid culture of Aspergillus sp. GZWMJZ-258, an endophyte from Garcinia multiflora (Guttiferae). The structures of compounds 1-3 were determined by nuclear magnetic resonance, mass spectrometry, Marfey's analysis of amino acids, and chemical calculation. Compounds 1-3 displayed selective inhibition on human FLT3-ITD mutant AML cell line, MV4-11, with IC50 values of 7.2, 10.0, and 0.22 µM, respectively.

Cytotoxic phenolic constituents from Hypericum japonicum.

Nine undescribed compounds, including five xanthone derivatives, two flavonoids, one 2-pyrone derivative, and one undescribed naturally occurring compound, along with 30 known phenolic compounds, were isolated from Hypericum japonicum. In addition, hyperjaponols A and B were identified as racemates. The structures and absolute configurations of the undescribed compounds were determined by comprehensive MS, NMR spectroscopy, and electronic circular dichroism (ECD) calculations. The cytotoxic effects of the isolated compounds on two human tumour cell lines (HEL and MDA-MB-231) were evaluated by the MTT assay. Eighteen compounds showed good inhibitory activities against the HEL cell line, with IC50 values of 3.53-18.7 µM, while nine compounds exhibited moderate cytotoxicity against the MDA-MB-231 cancer cell line, with IC50 values ranging from 4.92 to 10.75 µM. Their preliminary structure-activity relationship of the isolated compounds was also discussed.

Anticancer Activity of Saponins from Allium chinense against the B16 Melanoma and 4T1 Breast Carcinoma Cell.

The cytotoxic substance of A. chinense saponins (ACSs) was isolated using ethanol extraction and purified with the D101 macroporous adsorption resin approach. We investigated the anticancer activity of ACSs in the B16 melanoma and 4T1 breast carcinoma cell lines. Methylthioninium chloride and hematoxylin-eosin staining with Giemsa dyestuff were used when the cells were treated with ACSs. The results showed that the cells morphologies changed significantly; ACSs induced cell death in B16 and 4T1 cells based on acridine orange/ethidium bromide double fluorescence staining, with the number and degree of apoptotic tumor cells increasing as ACS concentration increased. ACSs inhibited the proliferation of B16 and 4T1 cells in a dose-dependent manner. They also inhibited cell migration and colony formation and exhibited a concentration-dependent effect. In addition, ACSs apparently inhibited the growth of melanoma in vivo. The preliminary antitumor in vivo assay revealed that early medication positively affected tumor inhibition action and effectively protected the liver and spleen of C57 BL/6 mice from injury. This study provides evidence for the cytotoxicity of ACSs and a strong foundation for further research to establish the theoretical basis for cell death and help in the design and development of new anticancer drugs.

Comparative analysis of genomics and proteomics in Bacillus thuringiensis 4.0718.

Bacillus thuringiensis is a widely used biopesticide that produced various insecticidal active substances during its life cycle. Separation and purification of numerous insecticide active substances have been difficult because of the relatively short half-life of such substances. On the other hand, substances can be synthetized at different times during development, so samples at different stages have to be studied, further complicating the analysis. A dual genomic and proteomic approach would enhance our ability to identify such substances, and particularily using mass spectrometry-based proteomic methods. The comparative analysis for genomic and proteomic data have showed that not all of the products deduced from the annotated genome could be identified among the proteomic data. For instance, genome annotation results showed that 39 coding sequences in the whole genome were related to insect pathogenicity, including five cry genes. However, Cry2Ab, Cry1Ia, Cytotoxin K, Bacteriocin, Exoenzyme C3 and Alveolysin could not be detected in the proteomic data obtained. The sporulation-related proteins were also compared analysis, results showed that the great majority sporulation-related proteins can be detected by mass spectrometry. This analysis revealed Spo0A~P, SigF, SigE(+), SigK(+) and SigG(+), all known to play an important role in the process of spore formation regulatory network, also were displayed in the proteomic data. Through the comparison of the two data sets, it was possible to infer that some genes were silenced or were expressed at very low levels. For instance, found that cry2Ab seems to lack a functional promoter while cry1Ia may not be expressed due to the presence of transposons. With this comparative study a relatively complete database can be constructed and used to transform hereditary material, thereby prompting the high expression of toxic proteins. A theoretical basis is provided for constructing highly virulent engineered bacteria and for promoting the application of proteogenomics in the life sciences.

Purification and cloning of lectin that induce cell apoptosis from Allium chinense.

A 8.7 kDa lectin with high agglutin activity was isolated by affinity chromatography and cloned from Allium chinense in this study. For the MTT assay, approximately 60 µg/ml A. chinense lectin (ACL) inhibited 50% of the human hepatoma Hep-3B cells grown after 48 h. In addition, no antiproliferative effect was observed on normal human umbilical vein endothelial cells (HUVEC) even at 100 µg/ml concentration. After treatments with ACL on Hep-3B cells, morphologic changes in the nucleus and cytoskeleton were observed under laser scanning confocal microscopy with 4',6-diamidino-2-phenylindole and tubulin Alexa Fluor 488 staining; whereas, the mitochondrial membrane potential was observed through Mito Tracker Red CMXRos staining. The results showed that ACL led to cell morphology and structure change (e.g., round cell shrinkage). Moreover, ACL resulted in significant change in the shape of the nucleus, damaged the cytoskeleton when tubulin was degraded, and reduced the mitochondrial transmembrane potential. By contrast, no changes were observed on HUVEC cells under the same treatment conditions. DNA fragmentation analysis was used to detect DNA damage. Western blot showed that ACL upregulated caspase-3 and Bax expression during apoptosis and cloned the structural gene of ACL with an open reading frame of 456 bp encoding 151 amino acid residues. The results showed that ACL is a potential anticancer drug.