Purpurides B and C,Two New Sesquiterpene Esters from the Aciduric Fungus Penicillium purpurogenum JS03‐21

Purpurides B and C ( 1 and 2 , resp.), two new sesquiterpene alcohol esters generated from a drimane‐type sesquiterpenoid lactone and an amino acid, together with two known analogs, berkedrimane B ( 3 ) and purpuride ( 4 ), were isolated from the aciduric fungus Penicillium purpurogenum JS03‐21. Their structures were elucidated by spectroscopic analysis, X‐ray single‐crystal diffraction, and application of Marfey's method. Compounds 1 – 4 showed modest antifungal activities against Candida albicans with MIC values in the range of 1.2–3.3 μM . Compounds 1 and 2 showed moderate antimicrobial activities against Enterobacter aerogenes and Pseudomonas aeruginosa with MIC values in the range of 1.2–2.6 μM .     

Novel 3‐Oxo‐ and 3,24‐Dinor‐2,4‐secooleanane‐Type Triterpenes from Terminalia ivorensis A. Chev.

Two new oleanane‐type triterpenes named ivorengenin A (=3‐oxo‐2α,19α,24‐trihydroxyolean‐12‐en‐28‐oic acid; 1 ) and ivorengenin B (=4‐oxo‐19α‐hydroxy‐3,24‐dinor‐2,4‐secoolean‐12‐ene‐2,28‐dioic acid; 2 ), together with five known compounds, arjungenin, arjunic acid, betulinic acid, sericic acid, and oleanolic acid, were isolated from the barks of Terminalia ivorensis A. Chev . (Combretaceae). Their structures were established on the basis of 1D‐ and 2D‐NMR data, and mass spectrometry. A biogenetic pathway to the formation of these compounds from sericic acid, isolated as the major compound from this plant, was proposed. The antioxidant activities of different compounds were investigated by means of the 2,2‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) and 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) assays, and IC₅₀ values were calculated and compared with Trolox activity. Antiproliferative activities of the isolated compounds were also evaluated against MDA‐MB‐231, PC3, HCT116, and T98G human cancer cell lines, against which the compounds showed significant cytotoxic activities.     

Caulerprenylols A and B,two rare antifungal prenylated para-xylenes from the green alga Caulerpa racemosa

Two new prenylated para-xylenes, named caulerprenylols A (1) and B (2), were isolated from the green alga Caulerpa racemosa, collected from the Zhanjiang coastline, China. The structures of the two metabolites were elucidated on the basis of detailed spectroscopic analysis. This is the first report of prenylated para-xylenes from marine algae and from marine organisms as well. Moreover, caulerprenylol B (2) is also characterized by an uncommon indane ring system. In in vitro bioassays, the new compounds exhibited a broad spectrum of antifungal activity against Candida glabrata (537), Trichophyton rubrum (Cmccftla), and Cryptococcus neoformans (32609) with MIC₈₀ values between 4 and 64 μg/mL when compared to amphotericin B (MIC₈₀ values of 2.0, 1.0, and 4.0 μg/mL, respectively) as a positive control and showed no growth inhibition activity against the tumor cells HL60 and A549.     

Synthesis and Biological Evaluation of Novel Oxazolo[5,4‐d]pyrimidines as Potent VEGFR‐2 Inhibitors

Tumor angiogenesis is mediated by vascular endothelial growth factor receptor (VEGFR) and other protein kinases. Inhibition of these kinases presents an attractive approach for developing anticancer therapeutics. In this work, a series of 2,5,7‐trisubstituted oxazolo[5,4‐d]pyrimidines were synthesized, and their inhibitory activities were investigated against VEGFR‐2 and human umbilical vein endothelial cells (HUVEC) in vitro. Compound 9n exhibited the most potent inhibitory activity with IC₅₀ values of 0.33 and 0.29 μM for VEGFR‐2 kinase and HUVEC, respectively. A further kinase selectivity assay revealed that these compounds exhibit good VEGFR and moderate EGFR inhibitory activities. Docking analysis suggested a common mode of interaction at the ATP‐binding site of VEGFR‐2.     

Varicuothiols A and B,New Fungal Metabolites from Aspergillus versicolor with Anti‐Inflammatory Activities

Chemical examination of a coral‐associated fungus Aspergillus versicolor LZD‐44‐03 resulted in the isolation of two new compounds with the trivial names of varicuothiols A ( 1 ) and B ( 2 ) as a unique scaffold. Their structures were determined through extensive spectroscopic analyses in association with the modified Mosher's method and chemical conversion. Both 1 and 2 exhibited significant inhibition against LPS‐induced RAW24.7 cell proliferation, in association with the down regulation of nitrite production and cytokines (MCP‐1, IL‐6, and TNF‐α).     

Two new imidazolone-containing alkaloids and further metabolites from the ascomycete fungus Tricladium sp

Tricladins A and B (1 and 2, resp.), new imidazolone-containing alkaloids, together with five known metabolites, bacillamides A, B (3 and 4, resp.), 20-hydroxyaflavinine (5), N-(2-phenylethyl)acetamide (6), and N(b)-acetyltryptamine (7), have been isolated from the crude extract of the ascomycete fungus Tricladium sp. The structures of 1 and 2 were elucidated primarily by NMR and MS methods. Compound 2 showed marginal cytotoxicity against MDA-MB-231 human breast cancer cells, whereas the known metabolite 4 displayed an inhibitory effect on HIV-1 replication in C8166 cells.     

New Pyran‐2‐ones from Alkalophilic Actinomycete,Nocardiopsis alkaliphila sp. Nov. YIM‐80379

Two new pyran‐2‐ones, nocardiopyrones A and B ( 1 and 2 , resp.), along with four known compounds, pyridinols 3 – 5 , and 1‐acetyl‐β‐carboline ( 6 ) were isolated from the alkalophilic actinomycete Nocardiopsis alkaliphila sp. nov. YIM‐80379. Their structures were established on the basis of spectroscopic analysis, CD spectra, and the quantum‐chemical ECD calculation. Pyridinols 3 – 5 were isolated from a natural source for the first time. Compounds 1 and 2 showed weak antibacterial activities against Pseudomonas aeruginosa, Enterobacter aerogenes, and Escherichia coli with MIC values of 20–48 μM . Compound 2 showed weak antimicrobial activities against Candida albicans and Staphylococcus aureus with MIC values of 24 and 48 μM , respectively.     

Pyriculins A and B,two monosubstituted hex‐4‐ene‐2,3‐diols and other phytotoxic metabolites produced by Pyricularia grisea isolated from buffelgrass (Cenchrus ciliaris)

Pyricularia grisea has been identified as a foliar pathogen on buffelgrass (Cenchrus ciliaris ) in North America and was studied as a potential source of phytotoxins for buffelgrass control. Two monosubstituted hex‐4‐ene‐2,3‐diols, named pyriculins A and B, were isolated from its culture filtrate organic extract together with (10S ,11S )‐(−)‐epipyriculol, trans ‐3,4‐dihydro‐3,4,8‐trihydroxy‐1(2H )‐napthalenone, and (4S )‐(+)‐isosclerone. Pyriculins A and B were characterized by spectroscopic (essentially nuclear magnetic resonance [NMR], High‐resolution electrospray ionization mass spectrometry [HRESIMS]) and chemical methods such as (4E )‐1‐(4‐hydroxy‐1,3‐dihydroisobenzofuran‐1‐yl)hex‐4‐ene‐2,3‐diols. The relative and absolute configuration of these compounds was determined by a combination of spectroscopic (NMR, electronic circular dichroism [ECD]) and computational tools. When bioassayed in a buffelgrass coleoptile and radicle elongation test, (10S ,11S )‐(−)‐epipyriculol proved to be the most toxic compound. Seed germination was much reduced and slowed with respect to the control and radicles failed to elongate. All five compounds delayed germination, but only (10S ,11S )‐(−)‐epipyriculol was able to prevent radicle development of buffelgrass seedlings. It had no effect on coleoptile elongation, while the other four compounds caused significantly increased coleoptile development relative to the control.     

A High‐Performance D–A Copolymer Based on Dithieno[3,2‐b:2′,3′‐d]Pyridin‐5(4H)‐One Unit Compatible with Fullerene and Nonfullerene Acceptors in Solar Cells

Development of high‐performance donor–acceptor (D–A) copolymers is vital in the research of polymer solar cells (PSCs). In this work, a low‐bandgap D–A copolymer based on dithieno[3,2‐b:2′,3′‐d]pyridin‐5(4H)‐one unit (DTP), PDTP4TFBT, is developed and used as the donor material for PSCs with PC₇₁BM or ITIC as the acceptor. PDTP4TFBT:PC₇₁BM and PDTP4TFBT:ITIC solar cells give power conversion efficiencies (PCEs) up to 8.75% and 7.58%, respectively. 1,8‐Diiodooctane affects film morphology and device performance for fullerene and nonfullerene solar cells. It inhibits the active materials from forming large domains and improves PCE for PDTP4TFBT:PC₇₁BM cells, while it promotes the aggregation and deteriorates performance for PDTP4TFBT:ITIC cells. The ternary‐blend cells based on PDTP4TFBT:PC₇₁BM:ITIC (1:1.2:0.3) give a decent PCE of 9.20%.     

高受体结合和低免疫原性的［B1—Ala，B2—Ala］－胰岛素

通过化学半合成从天然猪胰岛素得到［Ｂ１－Ａｌａ,Ｂ２－Ａｌａ］胰岛素。这一胰岛素类似物经聚丙烯酰胺凝胶电泳和ＨＰＬＣ鉴定证明是均一的,氨基酸组成与理论值相符生物活性测定结果表明：［Ｂ１－Ａｌａ,Ｂ２－Ａｌａ］－胰岛素的体内活力与天然猪胰岛素相同,而与人胎盘细胞膜胰岛素受体的结合能力为天然猪胰岛素的１３２％。这一结果进一步说明胰岛素Ｂ链Ｎ端肽段参子与受体相互作用。此外,［Ｂ１－Ａｌａ,Ｂ２－Ａｌａ］－胰岛素的免疫活性很低,远小于天然猪胰岛素的４％。     

Separation of the pentacyclic triterpenes tylolupenols A and B from Tylophora kerrii

Tylolupenols A and B from Tylophora kerrii were separated and identified as D:C-friedolup-8(9)-en-3β-ol and D:C-friedolup-9(11)-en-3β-ol, respectively.     

Reassortant DS‐1‐like G1P[4] Rotavirus A strains generated from co‐circulating strains in Vietnam, 2012/2013

One major mechanism by which Rotavirus A (RVA) evolves is genetic reassortment between strains with different genotype constellations. However, the parental strains of the reassortants generated have seldom been identified. Here, the whole genome of two suspected reassortants, RVA/Human‐wt/VNM/SP127/2013/G1P[4] and RVA/Human‐wt/VNM/SP193/2013/G1P[4], with short RNA electropherotypes were examined by Illumina MiSeq sequencing and their ancestral phylogenies reconstructed. Their genotype constellation, G1‐P[4]‐I2‐R2‐C2‐M2‐A2‐N2‐T2‐E2‐H2, indicated that they were G1 VP7 mono‐reassortants possessing DS‐1‐like genetic backbones. The two strains were ≧99.7% identical across the genome. While their VP7 genes were ≧99.7 identical to that of a Wa‐like strain RVA/Human‐wt/VNM/SP110/2012/G1P[8] which co‐circulated during the 2012/2013 season, 10 genes were ≧99.8% identical to that of the DS‐1‐like strains RVA/Human‐wt/VNM/SP015/2012/G2P[4] (and SP108) that co‐circulated during the season. The identities were consistent with the phylogenetic relationships observed between the genes of the reassortants and those of the afore‐mentioned strains. Consequently, the G1P[4] strains appear to have been generated by genetic reassortment between SP110‐like and SP015‐like strains. In conclusion, this study provides robust molecular evidence for the first time that G1P[4] strains detected in Hanoi Vietnam were generated by inter‐genogroup reassortment between co‐circulating G1P[8] and G2P[4] strains within the same place and season.

     

Distribution and clustering of two highly repeated sequences in the A and B chromosomes of maize

Summary Clones from a family of highly repeated sequences present in a heterochromatin rich maize line have been characterized by sequencing and chromosome location. The repeats differ from each other in length and degree of sequence homology, and show areas rich in purine and pyrimidine. In situ hybridization experiments indicate that the repeats are mainly located in the knob heterochromatin of the A chromosomes and the centromeric heterochromatin of the B chromosome. However, in addition to previously published data, some copies are also distributed in euchromatic regions of the A chromosomes and in the distal heterochromatic block of the B chromosome. The results are discussed in relation to the centromeric activity of maize heterochromatin.Research work is sponsored by C.N.R. Italy, Special grant I.P.R.A., Subproject 1, Paper No. 300