Mycosporins from Ascochyta pisi, Cladosporium herbarum and Septoria nodorum

The chemical structure of the mycosporin isolated from Ascochyta pisi, Cladosporium herbarum and Septoria nodorum was established as mycosporin-2 glucoside.     

Guaianolides from Centaurea canariensis

The aerial parts of Centaurea canariensis afforded four new guaianolides, all closely related to dehydrocostus lactone, and a derivative of costic acid. The structures were elucidated by spectroscopic methods.     

The tornabeatins, four tetrahydro-2-furanone derivatives from the lichenized ascomycete Tornabea scutellifera (With.) J.R. Laundon

Tornabeatins A, B, C and D, have been isolated as new natural products from the lichenized ascomycete Tornabea scutellifera, and their structures elucidated using UV, IR, MS, 1D and 2D NMR spectral data and chemical degradation.     

Alkaloids from stem barks of Oricia renieri and Oricia gabonensis

The stem barks of Oricia renieri and O. gabonensis have yielded nine alkaloids, including furoquinolines, acridones, 3,4-pyrano-2-quinolones and a 2-amino-benzophenone. One of the pyranoquinolones isolated from O. renieri, 7-methoxy-N-methylflindersine, is reported for the first time. All alkaloids were identified on the basis of spectral data. The chemotaxonomic significance of the alkaloids of these two species is discussed.     

A Stilbene derivative from Gnetum parvifolium

Gnetifolin F, a novel stilbene derivative, was isolated from the lianas of Gnetum parvifolium. The structure was deduced mainly by the use of ¹H-¹H COSY, ¹³C-¹H COSY, ¹³C-¹H COLOC and NOE difference spectrum, and verified with X-ray crystallographic analysis.     

Identification and characterization of GABA, proline and quaternary ammonium compound transporters from Arabidopsis thaliana

Arabidopsis thaliana grows efficiently on GABA as the sole nitrogen source, thereby providing evidence for the existence of GABA transporters in plants. Heterologous complementation of a GABA uptake-deficient yeast mutant identified two previously known plant amino acid transporters, AAP3 and ProT2, as GABA transporters with Michaelis constants of 12.9±1.7 and 1.7±0.3 mM at pH 4, respectively. The simultaneous transport of [1-¹⁴C]GABA and [2,3-³H]proline by ProT2 as a function of pH, provided evidence that the zwitterionic state of GABA is an important parameter in substrate recognition. ProT2-mediated [1-¹⁴C]GABA transport was inhibited by proline and quaternary ammonium compounds.     

Molecular characterization of strawberry pathogen Gnomonia fragariae and its genetic relatedness to other Gnomonia species and members of Diaporthales

Gnomonia fragariae is a poorly studied ascomycete belonging to Diaporthales. Originally G. fragariae was considered a saprophyte occurring on dead tissues of strawberry plants. Recently this fungus was found in Latvia and Sweden, and it was proven to be the cause of severe root rot and petiole blight of strawberry. Thirteen isolates of this pathogen and several other Gnomonia species occurring on rosaceous hosts were characterized by molecular analysis using nucleotide sequences of partial LSU rRNA gene and the total ITS region. The homologous regions from relevant diaporthalean taxa available in the GenBank were also included and compared with the taxa sequenced in this study. Phylogenetic analyses revealed that G. fragariae, G. rubi, and Gnomonia sp. (CBS 850.79) were genetically different from G. gnomon, the type species of the genus, and other members of Gnomoniaceae. The analyses showed that G. fragariae and Hapalocystis were genetically very closely related, forming a phylogenetic clade, which is possibly presenting a new family in the Diaporthales. Morphological comparisons of the Gnomonia species on the basis of commonly used criteria for the taxonomy of Diaporthales, so far did not reveal any evident features for the polyphyletic status of Gnomonia.     

油葵HaFAD2-2基因的克隆及表达分析

脂肪酸脱氢酶2(fatty acid desaturase,FAD2)催化油酸生成亚油酸,是植物体内生成多不饱和脂肪酸的关键酶。根据已报道的向日葵(Helianthus annuus L.)FAD2基因序列,设计引物进行RT-PCR,克隆得到油葵FAD2-2基因全长cDNA,命名为HaFAD2-2。该基因开放阅读框为1 152bp,编码383个氨基酸,相对分子质量43.96kD,等电点为8.56。对基因组进行内含子调查发现,该基因在编码区内没有内含子。多序列比对和系统进化分析发现,FAD2-2基因编码蛋白与金盏菊(Calendula officinalis)、斑鸠菊(Vernonia galamensis)等菊科植物具有较近的亲缘关系。qRT-PCR分析表明,HaFAD2-2基因在根、茎、叶、花、子叶和未成熟种子中均有表达,且以叶中的表达量最高,未成熟种子中的表达量最低;低温(5℃、15℃)胁迫处理能显著促进该基因在根中的表达,抑制其在叶中的表达;盐胁迫(300 mmol/L NaCl)处理对其表达也具有抑制作用。该研究结果可为进一步探讨HaFAD2-2基因的功能奠定基础。     

Synthesis of 2-deoxyglucitol from 2-deoxy-D-glucose by the fungus Puccinia graminis

After incubation of glucose-grown mycelium of Puccinia graminis with 2-deoxy-D-[U-¹⁴C]glucose, all cellular ¹⁴C was present in compounds soluble in 80% (v/v) ethanol. Metabolites identified included 2-deoxyglucitol, and free and phosphorylated forms of 2-deoxyglucose and 2-deoxygluconate. This is the first report of 2-deoxyglucitol as a metabolite of 2-deoxyglucose in any organism, and in P. graminis, this confirms previous proposals that the free D-glucose is directly reduced to D-glucitol in vivo.     

齿菌子实体的化学成分研究

利用硅胶柱层析和Sephadex LH-20凝胶柱层析分离手段,从高等真菌齿菌(Hydnellumsp.No.2)子实体的甲醇提取物中分离鉴定了7个化合物,经现代光谱学技术鉴定为麦角甾-7,22-二烯-3β-醇(1)、5α,8α-过氧麦角甾-6,22-二烯-3β-醇(2)、(22E,24R)-3β-羟基-24-甲基胆甾-5,22-二烯-7-酮(3)、对羟基苯甲酸甲酯(4)、(24R)-麦角甾-7,22-二烯-3β,5α,6β-三醇(5)、Tuberoside(6)和脑苷脂B(7)。化合物4、5、6、7为该属首次报道。     

A naphthalenoid pulvinic acid derivative from the fungus Pisolithus tinctorius

Fruitbodies of the ectomycorrhizal fungus Pisolithus tinctorius contain a high concentration of a naphthalenoid pulvinic acid derivative, which was identified by chemical and spectroscopic methods.     

中国水仙NtPI2基因的克隆及遗传转化

采用RT-PCR和RACE技术,从中国水仙‘金盏银台’中获得1个MADS-box基因NtPI2。NtPI2基因全长810bp,含有1个627bp开放阅读框,编码208个氨基酸。系统进化树显示,NtPI2属于B类MADS-box基因家族的PI/GLO类基因。荧光定量PCR分析表明,NtPI2基因在中国水仙‘金盏银台’各营养器官中都有表达;在单瓣和重瓣水仙花朵的各个部位均有表达,但表达模式存在差异。比较NtPI2在单瓣和重瓣中国水仙中的表达模式,发现重瓣水仙‘玉玲珑’的瓣化雄蕊和副冠的NtPI2基因表达量较单瓣水仙‘金盏银台’显著增高,推测NtPI2基因在瓣化雄蕊中表达量显著增高可能是重瓣中国水仙发生的直接原因。成功构建了NtPI2基因的pCAMBIA1302-NtPI2超表达载体,并通过农杆菌介导法进行烟草的遗传转化,分子鉴定结果表明共获得了8株转NtPI2基因植株。本研究为深入探索NtPI2基因的功能及其与中国水仙重瓣花形成的关系奠定了基础。     

Iridoids from Catalpa bignonioides

Five new iridoids and related glucosides have been isolated from the methanol extract of Catalpa bignonioides root, along with a new phenylethanoid diglycoside. In addition, known iridoid glucosides, catalposide, amphicoside, 6-O-veratryl catalposide and minecoside were identified.     

Inheritance of chromosomal length polymorphisms in the ascomycete Leptosphaeria maculans

Pulsed field gel electrophoresis experiments show that chromosomal length polymorphisms are produced during meiosis in the ascomycetous plant pathogen Leptosphaeria maculans. Homologues in tetrads of L. maculans were identified on the basis of their binding to chromosome-specific probes that included -tubulin, nitrate reductase, 18S ribosomal DNA and two Random Amplified Polymorphic DNA (RAPD) markers. Changes in size of homologues were followed during meiosis. Significant karyotype variation was evident due to the random assortment of parental homologues of different sizes. In most cases, the progeny had the same-sized homologues as the parents; however, in some instances novel-sized homologues were detected that varied in size from those of the parents by up to 50 kb. Our results are consistent with the hypothesis that these novel chromosomal length polymorphisms are produced by reciprocal recombination between parental homologous chromosomes of unequal sizes.     

Aromatic compounds from Delphinium venulosum

From the non-alkaloidal fractions of Delphinium venulosum, four known aromatic compounds cis and trans p-coumaric acids, p-hydroxybenzoic acid, protocatechuic acid methyl ester and a new aromatic compound 2,5,6-trihydroxypiperonylic acid methyl ester were isolated together with kaempferol, sitosterol and sitosteryl 3-glucoside. The structures of the compounds were established by spectral data.     

In organello replication and viral affinity of linear, extrachromosomal DNA of the ascomycete Ascobolus immersus

Summary Linear, extrachromosomal DNA's of the filamentous fungus Ascobolus immersus are localized within the mitochondria. These linear plasmids have no homology to the high molecular weight mtDNA (hmw mtDNA). For analysis of plasmid replication an in organello DNA synthesis system was developed, in which radionucleotides were incorporated into intact mitochondria. Plasmid DNA is labelled preferentially in this system. From replication analysis of a specific plasmid there is evidence of a virus-like protein-primed replication. Sequence analysis of this plasmid reveals that a viral DNA polymerase is encoded. Thus, these genetic elements presumably are viral remnants rather than true plasmids.     

Chemical variation within and between individuals of the lichenized ascomycete Tephromela atra

HPLC-analysis was used to determine the concentrations of the lichen compounds alectoronic acid (depsidon), -collatolic acid (depsidon) and atranorin (depsid) in the lichenized ascomycete Tephromela atra (syn. Lecanon atra) (Hudson) Hafeliner from limestone walls on the Baltic island of Öland, Sweden. In 24 individuals of T. atra sampled on a stone wall, the pre-reproductive and reproductive tissue did not differ in the concentrations of alectoronic acid, collatolic acid and atranorin. The concentrations of the three lichen compounds were inter-correlated in the reproductive tissue, but not in the pre-reproductive tissue. Single individuals of T. atra ranged in area covered from 10.1 to 147.4 cm² (mean: 38.5 cm²; N=24); 38.6% of this area was pre-reproductive tissue. However, the concentrations of the three lichen compounds were correlated neither with the total area covered by the lichen nor with the percentage of pre-reproductive tissue. This suggests that the concentrations of the lichen compounds do not change with increasing size (age) of the lichen. Analysis of specimens of T. atra from eight localities revealed a significant variation in lichen compounds (range between localities: alectoronic acid 0.60–3.26 μg/mg lichen dry weight (DW); collatolic acid 2.14–11.59 μg/mg lichen DW; atranorin 0.58–4.16 μg/mg lichen DW). The level of grazing observed in the lichens differed significantly among localities. However, no correlations between the concentrations of the three lichen compounds and the grazing damage to the lichens were found.     

Chemical constituents from the fungus Monascus purpureus and their antifungal activity

One new cyclohex-2-enone derivative, purpureusone (1), together with seven known compounds (2–8) were isolated from the n-BuOH-soluble fraction of the 95% EtOH extract of the red yeast rice fermented with the yellow mutant of the fungus Monascus purpureus BCRC 38038. Their structures were characterized by direct interpretation of their spectroscopic methods, including 1D NMR (¹H, ¹³C NMR, DEPT), 2D NMR (COSY, NOESY, HSQC and HMBC), and HRESIMS. Purpureusone (1) contains a cyclohex-2-enone skeleton connected with one γ-lactone ring, one octanoyl, and 2-oxopentyl side chains. Some isolates were evaluated for their antifungal effect against Candida albicans and Saccharomyces cerevisiae using a TLC bioautographic method. Compound 1 showed antifungal inhibitory activity in vitro.     

Characterization and cloning of plasmid like DNA of the ascomycete Podospora anserina

Summary The previously reported existence of plasmid-like (pl) DNA in senescent mycelia of Podospora anserina was confirmed using new methodology. Detailed analysis of bulk DNA has further shown a possible relationship between pl DNA and mt DNA.According to biophysical and electron microscopic experiments the pl DNA was found to consist of oligomeres having a basic unit with a contour length of 0.75 m corresponding to 2.4 kb. To overcome the handicap that pl DNA is only produced in rather small amounts in the aging mycelia, this DNA was cloned in E. coli after insertion into a bacterial plasmid vector, pBR 322. It was possible to isolate a stable hybrid plasmid consisting of the vector and only one integrated monomere of pl DNA. The composition of this hybrid plasmid was confirmed by restriction endonuclease analysis and heteroduplex formation. A restriction map of the pl DNA is presented and its insertion site onto pBR 322 indicated.     

Allantoin and allantoic acid titre in the faeces and tissues of the developing larva of the moth, Orthaga exvinacea Hampson

Allantoin and allantoic acid are investigated in the faeces and tissues of the developing sixth instar larva of the moth, Orthaga exvinacea. The nitrogen excreted as allantoin and allantoic acid is compared with nitrogen excreted as uric acid and ammonia. The larva excretes 2.35–5.14 μmol/g allantoin and 0.74–1.34 μmol/g allantoic acid which account for 0.83 to 2.39% and 0.23 to 0.53%, respectively, of the excreted total nitrogen. Allantoin and allantoic acid are found to be minor nitrogenous end-products of the larva. Allantoin and allantoic acid are also present in the haemolymph and fat body of the larva in varying concentrations. The level of allantoin in the haemolymph shows a negative correlation with the allantoin concentration of faeces and fat body. The allantoin is found to be stored in the fat body at a low level. The results of the present study also indicate the coexistence of uric acid storage and uricolysis.