Homologiekriterien oder Argumentationsverfahren?

In der herkömmlichen Formulierung der Homologiekriterien (vgl. Remane 1956: 58) wird das Wort “homolog” sowohl im Sinne von “gefügegleich” als auch “korrelierbar mit anderen Merkmalen” verwendet. Sie stellen Grundsätze auf und geben, ohne logische Unterscheidung, Wege an, diese Ziele zu erreichen. Als Ursache dieser Verwirrung wird die mangelhafte Unterscheidung der beiden Typuskonzepte nachgewiesen, welche in der Vergleichenden Morphologie einerseits und in der Taxonornie andererseits sowohl zur Musterfixierung als auch zur Mustererkennung Verwendung finden: Merkmalsleerer Gefügetypus und merkmalsgesättigter Korrelationstypus. Zu jedem der beiden Typuskonzepte gehört ein Verfahren, das angibt, wie mit den schwierigeren Fällen jeweils zu verfahren sei. Das Typologische Beweisverfahren wird näher dargestellt. Die in den Homologiekriterien niedergelegten Sätze können nach entsprechender Umformulierung in der aus Schema 10 ersichtlichen Weise auf die beiden Verfahren verteilt werden.     

PRODUCTION OF SECONDARY METABOLITES BY FILAMENTOUS TROPICAL MARINE CYANOBACTERIA: ECOLOGICAL FUNCTIONS OF THE COMPOUNDS

Cyanobacterial blooms are becoming more common in many reef habitats. The broadly acting feeding deterrent compound ypaoamide, produced by a mixed cyanobacterial assemblage, has been linked to bloom formation and mass fish die-offs ( Siganus argenteus and Siganus spinus ) in Guam. Specific metabolites produced by Lyngbya majuscula Gomont act as both feeding attractants to the specialist herbivore Stylocheilus longicauda , and as effective feeding deterrents to generalist fishes. Two-dimensional TLC (2D-TLC) analysis of cyanobacterial crude extracts was used to select chemically distinct populations (chemotypes) of bloom-forming filamentous cyanobacteria for chemical and ecological evaluation. Crude extracts produced by different species, chemotypes, and chemically distinct Micronesian marine cyanobacterial assemblages deter feeding activity of generalist reef herbivores. The ecological function of cyanobacterial secondary metabolites, especially as related to diversity of compound production and the relationship of metabolite production to bloom formation is discussed.     

Taxonomic position and nitrogen-containing secondary metabolites of the fungusPenicillium vitale pidoplichko et bilai apud bilai

The type strainPenicillium vitale Pidoplichko et Bilai apud Bilai 1961 VKM F-3624 was found to considerably differ from a sibling speciesP. janthinellium (syn.P. simplicissimum) in some physiological and morphological features (growth rates at different temperatures, the size of philiades, and the shape of conidia), as well as in the pattern of the nitrogen-containing secondary metabolites produced (roquefortine, 3,12-dihydroroquefortine, meleagrin, aurantioclavine, indole-3-acetic acid, andN-acetyltryptamine). The data obtained suggest thatP. vitale represents an independent species.     

Hypomiltin,a novel azaphilone from <Emphasis Type="Italic">Hypoxylon hypomiltum</Emphasis>, and chemotypes in <Emphasis Type="Italic">Hypoxylon</Emphasis> sect. <Emphasis Type="Italic">Hypoxylon</Emphasis> as inferred from analytical HPLC profiling

A novel azaphilone named hypomiltin was isolated by preparative reversed phase HPLC from the stromatal extract of the xylariaceous ascomycete Hypoxylon hypomiltum. Its chemical structure was determined by mass spectrometry and 2D nuclear magnetic resonance spectroscopy. Analytical HPLC profiling of stromatal crude extracts, using UV/visual (diode array) and mass spectrometric detection based on electrospray ionisation, revealed the presence of hypomiltin also in Hypoxylon intermedium, H. perforatum, H. trugodes, and Pulveria porrecta. In contrast, this compound was found neither in type material of H. hypomiltum var. lavandulocinereum nor in several further Hypoxylon species. Despite being chemically related to mitorubrin, hypomiltin never co-occurred with the latter compound and its derivatives. Characteristic secondary metabolite profiles of several further Hypoxylon species are correlated with the colours of their taxonomically significant KOH-extractable pigments. These species are divided into chemotypes, based on analytical HPLC data. The results point toward an extraordinary diversity of secondary metabolites in Hypoxylon. Dedicated to Timm Anke, Kaiserslautern, on the occasion of his 60th birthday     

红树林放线菌研究进展

红树林是生长在热带和亚热带海岸潮间带的一种独特植物群落,构成陆地与海洋间的过渡,具有水分高、盐分高、耐缺氧等特征的特殊生态系统及很高的生物多样性,是筛选和发现放线菌新物种和药用生物活性次级代谢产物的宝贵资源。在物种鉴定方面,放线菌分类学是目前红树林放线菌物种鉴定的重要手段。本文综述了红树林放线菌物种鉴定主要方法、红树林放线菌生态环境和物种分布特征、生物学活性及其次级代谢产物等,并展望了该领域研究与发展的重要问题与趋势。     

Mutagens manufactured in fungal culture may affect DNA/RNA of producing fungi

Self-produced mutagens in culture by fungi may affect DNA analysis of the same fungi. This has not been considered previously. Many fungi produce numerous mutagenic secondary metabolites (SM) in culture. There is a paradox of growing fungi in media to produce representative DNA which also support mutagenic SM. This is a crucial issue in developing diagnostic and phylogenetic methods, especially for closely-related fungi. For example, idh gene analysis of the patulin metabolic pathway in fungi can be interpreted as producing some false negative and positive results in terms of possession, or nonpossession, of the gene from mutated strains. The most obvious mycotoxins and fungi to consider in this regard are aflatoxins and Aspergillus , as aflatoxins are the most mutagenic natural compounds. Many other fungi and SM are relevant. Conditions to grow fungi have not been selected to inhibit SM production although relevant data exist. In fact, fungi repair damaged nucleic acid (NA) and are capable of removing toxins by employing transporter proteins. These and NA repair mechanisms could be inhibited by secondary metabolites. Mutagenic effects may involve inhibition of DNA stabilizing enzymes. There may be an equivalent situation for bacteria. Researchers need to devise methods to reduce SM for valid protocols. More work on how mutagens affect the NA of producing fungus in vitro is required. The current review assesses the potential seriousness of the situation with selected papers.     

An improved Greengenes taxonomy with explicit ranks for ecological and evolutionary analyses of bacteria and archaea

Reference phylogenies are crucial for providing a taxonomic framework for interpretation of marker gene and metagenomic surveys, which continue to reveal novel species at a remarkable rate. Greengenes is a dedicated full-length 16S rRNA gene database that provides users with a curated taxonomy based on de novo tree inference. We developed a ‘taxonomy to tree'' approach for transferring group names from an existing taxonomy to a tree topology, and used it to apply the Greengenes, National Center for Biotechnology Information (NCBI) and cyanoDB (Cyanobacteria only) taxonomies to a de novo tree comprising 408 315 sequences. We also incorporated explicit rank information provided by the NCBI taxonomy to group names (by prefixing rank designations) for better user orientation and classification consistency. The resulting merged taxonomy improved the classification of 75% of the sequences by one or more ranks relative to the original NCBI taxonomy with the most pronounced improvements occurring in under-classified environmental sequences. We also assessed candidate phyla (divisions) currently defined by NCBI and present recommendations for consolidation of 34 redundantly named groups. All intermediate results from the pipeline, which includes tree inference, jackknifing and transfer of a donor taxonomy to a recipient tree (tax2tree) are available for download. The improved Greengenes taxonomy should provide important infrastructure for a wide range of megasequencing projects studying ecosystems on scales ranging from our own bodies (the Human Microbiome Project) to the entire planet (the Earth Microbiome Project). The implementation of the software can be obtained from http://sourceforge.net/projects/tax2tree/.     

Introduction

The only concrete basis for the discontinuous and hierarchical organization of extant organisms lies in their genealogical (i. e. germ line) relationships. Individuals and populations of common descent are called sib or stirps. Ideally, systematic classification is based on the formulas: (1) sib + taxonomic category + name = taxon, and (2) divergent genealogy of sibs + hierarchy of taxonomic categories + names = taxonomic system (Fig. 1).Presented at the symposium Speciation and the Species Concept during the XIIth International Botanical Congress, Leningrad, July 8, 1975.     

毛茛科分子系统发育研究进展

毛茛科(Ranunculaceae)在被子植物的系统演化中占有十分重要的地位,其系统位置和科下演化关系一直备受争议。近20多年的分子系统学研究表明,以往基于形态学的分类系统与分子系统学研究结果存在巨大差异。通过形态学性状界定的绝大多数亚科都没有得到分子系统学支持。此外,通过形态学确定的一些属如升麻属(Cimicifuga)、黄三七属(Souliea)、獐耳细辛属(Hepatica)、白头翁属(Pulsatilla)和水毛茛属(Batrachium)等,根据分子系统学研究均应予以归并。而分子系统学研究也确立了一些类群的属级地位,如露蕊乌头属(Gymnaconitum)等。以中国分布的毛茛科植物为例,通过以往分子系统学研究,共有10个属被归并,2个属新被确立。然而,毛茛科分子系统学研究对于科下许多类群之间的关系目前仍然没有得到很好的解决,如毛茛亚科和翠雀族等类群的系统发育关系仍需要进行深入研究后方能确定。该文对近年来国内外有关毛茛科的分子系统学研究进展进行了综述,并对该科尚存的一些问题和未来的研究方向进行了讨论。