Are tropical fungal endophytes hyperdiverse?

Fungal endophytes are ubiquitous fungi that inhabit healthy plant tissues without causing disease. Endophytes have been found in every plant species examined to date and may be important, but often overlooked, components of fungal biodiversity. In two sites in a lowland, moist tropical forest of central Panama, we quantified endophyte colonization patterns, richness, host preference, and spatial variation in healthy leaves of two co-occurring, understory tree species [ Heisteria concinna (Olacaceae) and Ouratea lucens (Ochnaceae)]. From 83 leaves, all of which were colonized by endophytes, we isolated 418 endophyte morphospecies (estimated 347 genetically distinct taxa), most of which were represented by only a single isolate (59%). Among morphospecies encountered in more than one leaf (nonsingletons), we found evidence of host preference and spatial heterogeneity using both morphospecies frequencies and presence/absence records. Based on these data, we postulate that tropical endophytes themselves may be hyperdiverse and suggest that extrapolative estimates that exclude them will markedly underestimate fungal species diversity.     

基于叶绿体DNA trnL内含子序列数据的檀香目科间系统发育关系的研究

应用叶绿体DNAtrnL内含子序列分析檀香目科间的系统发育关系。取样研究的檀香目个体的trnL内含子序列长度在科间呈现较大差异(从291bp到587bp)。最大简约性分析产生的严格一致树与以前已发表的基于其它基因的檀香目的分子系统学研究结果大体一致。香芙木属(铁青树科)是最早分支出的类群：桑寄生科、槲寄生科分别表现为单系类群,檀香科为并系;桑寄生科和槲寄生科并不具密切亲缘关系,槲寄生科从檀香科内衍生出来。本研究表明,具相对高的核苷酸替换率的叶绿体DNAtrnL内含子序列可为高等级类群系统发育关系的研究提供更多的信息位点。     

Cyclohexanoid protoflavanones from the stem-bark and roots of Ongokea gore

Phytochemical investigation of root and stem-bark of the West African medicinal plant Ongokea gore resulted in the isolation of four novel flavonoids with an unusual cyclohexyl substituent instead of the common aromatic ring B. The structures of the isolated compounds were elucidated by spectroscopic methods, mainly 1D and 2D NMR, and subsequently, the structures were corroborated by chemical conversion to (-)-(S)-sakuranetin. The absolute configurations, and preferred conformations were determined by NOE experiments and CD measurements.     

Three new D:A Friedo-oleanane triterpenes from the stem bark of Anacolosa poilanei and their cytotoxic activities

Three new D:A friedo-oleanane triterpenes, 3α-p-coumaroyl-D:A-friedo-oleanan-27-oic acid (1), 3α-(3,4-dihydroxycinnamoyl)-D:A-friedo-oleanan-27-oic acid (2), and 3α-(3,4-dihydroxycinnamoyl)-D:A-friedo-oleanan-27,15α-lactone (3) along with three known compounds, trichadenic acid A (4), trichadonic acid (5), and amentoflavone (6), were isolated from the stem barks of Anacolosa poilanei Gagnep. Their structures were established by spectral analysis, such as mass spectrometry, 1D-NMR, and 2D-NMR. Compound 1 exhibited cytotoxicity against LU-1, HepG2, MCF7, and KB cell lines. Compounds 2 and 3 were more active against KB and HepG2 compared to the LU-1 and MCF7 cells.     

Olaxoside,a saponin from Olax andronensis, Olax glabriflora and Olax psittacorum

A new saponin, olaxoside, has been isolated from the methanol extract of the leaves, roots and barks of Olax andronensis, O. glabriflora and O. psittacorum. Structure determination was performed by spectroscopic and chemical methods. The anti-inflammatory and laxative activities are discussed briefly.