Terminology and nomenclature of protist cell surface structures

Summary The use of a precise terminology is important to the unambiguous exchange of information in the multidisciplinary area of protistology. In this paper we attempt to establish clear definitions, give illustrations, and comment on the different terms used for cell surface structures of protists and related organisms.     

Fungi allergic pathologies: correlation between allergological tests and presence of fungi in the upper respiratory tract

In order to clarify the aetiological role of fungi in determining allergic diseases, we evaluated the correlation between the positive skin test response to fungal allergens and the presence of the same species in the upper respiratory tract in 193 patients with suspected allergic disease to fungi. The results of our study have shown that the isolation and identification of the fungal flora from the patient’s respiratory tract, in addition to the medical history, the symptomatology, and the diagnostic in vivo and in vitro, can be helpful to identify the species responsible for provoking the allergic manifestations, and can be recommended either as a supplement to the diagnosis or as a guidance in elimination treatment.     

Depsipeptides from Metarhizium anisopliae

From the culture medium of a strain of Metarhizium anisopliae, 14 depsipeptides have been isolated. Five of them were identified as known destruxins A, B, C, D and desmethyldestruxin B. The structures of the new compounds, named destruxins E, A₁, A₂, B₁, B₂, C₂, D₁, D₂ and E₁,were established mainly from the mass spectral analysis of their corresponding open-chain derivatives.     

Sterols synthesized by cultured trichomycetes

Desmosterol was synthesized by all but 2 of 14 isolates of the fungal genus Smittium (Harpellales) obtained from the hindguts of various Diptera larvae and grown axenically on a sterol-free medium. Also detected in some isolates of Smittium were cholesterol and ergosterol, and another, unidentified sterol with an apparent molecular ion of 470. Sterol content based on dry weight of fungal tissue was as high as 0.34%, but it was shown in one isolate that sterols vary both quantitatively and qualitatively during growth of the fungus. Two axenic cultures of the trichomycete Amoebidium parasiticum (Amoebidiales) isolated from the exoskeleton of a Cladocera contained cholesterol and ergosterol, but no desmosterol. Two soil fungi with possible phylogenetic affinities to Smittium, Linderina pennispora and Dipsacomyces acuminosporus (Kickxellales), produced cholesterol alone. The possible influence of the gut fungi on arthropod growth and development is discussed.Abbreviations TMS trimethylsilyl Based upon a Master of Arts thesis submitted by the senior author to the Department of Botany, University of Kansas. This research was partially supported by NSF grants BMS 72-02380-AO and DEB 77-16161 to R.W.L.     

Trophic interactions in changing landscapes: responses of soil food webs

Soil communities in landscapes that are rapidly changing due to a range of anthropogenic processes can be regarded as highly transient systems where interactions between competing species or trophic levels may be seriously disrupted. In disturbed communities dispersal in space and time has a role in ensuring continuity of community function. Stable communities, in undisturbed systems, are more dependent on competition and other biotic interactions between species. We predicted how food web components would respond to disturbance, based on their dispersal and colonizing abilities. During decomposition, flows of energy and nutrients generally follow either a bacterial-based path, with bacteria as the primary decomposer and bacterial-feeding fauna and their predators forming the associated food web, or a fungal-based channel. Trophic links that were generally resistant to change were the organisms of the bacterial pathway that have high abilities to disperse in time and passively disperse in space. Organisms in the fungal pathway were less resistant to disturbance. Resource inputs to the soil system are derived from plants, either through root exudation and root turnover during active growth or from dead plant material following senescence or agricultural tillage. Disturbances to the soil system can arise as a direct action on the soil, or indirectly from effects on the above-ground plant community. Disturbance-induced changes in plant community composition will change the soil food web composition. Organisms involved in direct interactions with plants (e.g. AM-mycorrhizal fungi) were also predicted to be vulnerable to disturbance.

Zusammenfassung

Bodengemeinschaften in Landschaften, die sich aufgrund einer Reihe von anthropogenen Prozessen schnellstens verändern, können als sehr kurzlebige Systeme angesehen werden, in denen Interaktionen zwischen konkurrierenden Arten oder trophischen Leveln nachhaltig unterbrochen sind. In gestörten Gemeinschaften hat die Ausbreitung in Raum und Zeit eine Rolle bei der Wahrung der Kontinuität von Gemeinschaftsfunktionen. Stabile Gemeinschaften, in ungestörten Systemen, sind stärker von Konkurrenz und anderen biotischen Interaktionen zwischen den Arten abhängig. Wir sagten voraus, wie Nahrungsnetzkomponenten auf Störung antworten würden, basierend auf ihrer Ausbreitungs- und Kolonisationsfähigkeit. Während der Zersetzung folgen die Flüsse von Energie und Nährstoffen im Allgemeinen entweder einem Weg, der auf Bakterien basiert, mit Bakterien als den primären Zersetzern und bacterienfressender Fauna und ihre Predatoren, die das assoziierte Nahrungsnetz bilden, oder sie folgen einem Kanal, der auf Pilzen basiert. Trophische Verknüpfungen, die im Allgemeinen resistent gegen Veränderungen waren, waren die Organismen des bakteriellen Weges, die große Möglichkeiten haben sich in Zeit und passiv im Raum auszubreiten. Organismen des pilzbasierten Weges waren weniger widerstandsfähig gegenüber Störungen. Die Ressourcenzufuhr in das Bodensystem stammte von Pflanzen, entweder über Wurzelausscheidungen und/oder Wurzelturnover während des aktiven Wachstums oder von totem Pflanzenmaterial aufgrund von Seneszenz oder landwirtschatlicher Bodenbearbeitung. Störungen des Bodensystems können durch direkte Einwirkungen auf den Boden oder indirekt durch Effekte der oberirdischen Pflanzemeinschaft entstehen. Störungsinduzierte Veränderungen in der Zusammensetzung der Pflanzengemeinschaft werden die Zusammensetzung des Bodennahrungsnetzes verändern. Für Organismen, die an direkten Interaktionen mit Pflanzen beteiligt sind (beispielsweise AM-Mykorrhizapilze), wurde ebenfalls vorhergesagt, dass sie anfällig für Störungen sind.     

DNA metabarcoding reveals compositional and functional differences in fungal communities among Amazonian canga formations

Fungi execute many ecosystem functions and are thus expected to contribute substantially to ecosystem stability along environmental gradients. Here, we aimed to describe the fungal communities along a vegetation gradient found in Amazonian cangas using ITS2 metabarcoding. Rupestrian canga vegetation covers ironstone outcrops from the Carajás National Forest and the Campos Ferruginosos National Park of the Eastern Amazon. We detected 3574 operational taxonomic unit sequences dominated by the phyla Ascomycota, Basidiomycota, and Glomeromycota. The taxonomic and functional groups differed among periodically inundated grasslands (GR), typical scrublands (SB), Vellozia scrublands (VL), and woodlands (WD). Saprotrophic fungi were the most abundant, occurring primarily in WD, while stress-tolerant lineages and functional groups were dominant in environments with less soil. Our results provide new insights into the fungal ecology on ironstone outcrops and shed light on the importance of these organisms in enabling growth of vegetation cover, promoting species coexistence and increasing degrees of plant diversity in these harsh environments.     

医院获得性真菌尿路感染的临床特点

目的 :了解我院真菌尿路感染现状 ,探讨防治对策。方法 :回顾分析 1998～ 2 0 0 0年我院医院感染调查中 73例真菌尿路感染的临床特点。结果 :平均年龄 5 4 4 9岁 ,≥ 6 0岁占 4 2 4 7% ,平均住院日5 4 76d ;见于多种基础疾病 ,与恶性肿瘤、长期卧床、危重疾病有关 ;发生真菌感染前抗生素使用率 10 0 % ,78 0 8%联用两种以上抗生素 ,平均使用抗生素时间为 (35± 14 )d ;感染前应用激素者 2 7,4 0 % ,化疗16 4 4 % ,导尿等泌尿操作 4 7 95 % ;临床表现不典型 ,抗真菌治疗效果欠佳 ,病死率 2 4 6 6 %。结论 :年龄大、住院时长、长期卧床及需长期应用抗生素者 ,无论是否导尿 ,均易发生真菌尿路感染 ,应随时监测 ,以便及时采取综合治疗措施 ,降低病死率。     

Differentiation ofFusarium sambucinum Fuckel sensu lato and related species by RAPD PCR

DNA polymorphisms generated by the random amplified polymorphic DNA polymerase chain reaction (RAPD PCR) were used to analyse 41 isolates investigated in the EuropeanFusarium sambucinum Project (EFSP). Employing ten arbitrary (10-mer) oligonucleotides and simple repeat sequences (M13, (GACA)₄) as single primers, informative banding patterns typical for identifying European populations ofFusarium sambucinum Fuckel s. str.,F. torulosum (Berk. & Curt.) Nirenberg andF. venenatum Nirenberg were obtained.     

Fungal ferritins: The ferritin from mycelia of Absidia spinosa is a bacterioferritin

Two distinct ferritin like iron containing proteins have been identified and isolated from the fungus Absidia spinosa; one from the spores and another from the mycelia. The mycelial protein has been purified and consists of two subunits of approx. 20 kDa. The N-terminal sequences of both subunits have been determined. The holoprotein as isolated contains approx. 750 iron atoms/molecule and exhibits a heme-like UV-Vis spectrum. Based on the heme spectrum and the high degree of sequence homology found, it has been established that the mycelial protein is a bacterioferritin. This is the first example demonstrating the presence of a bacterioferritin in a eukaryotic organism.