Bruno Granetti

Morphological characterization of molecular-typed Tuber magnatum ectomycorrhizae

Abstract. Recent reports of discrepancies between the morphological and molecular-based characterization of Tuber magnatum ectomycorrhizae suggest misleading morphological typing of these structures. This study reports a new morphological and anatomical description of T. magnatum ectomycorrhizae at different development stages using nursery-inoculated host plants. Both ascocarps, used as spore donors in the inoculation process, and the resulting ectomycorrhizae were first checked by single-step PCR analysis using a T. magnatum species-specific ITS primer pair. Direct sequence analysis of the entire ITS1–5.8S-ITS2 fragment of DNA from mycorrhizal pools demonstrated the purity of the samples processed. Thus, the validity of the criteria reported here for the morphological identification of T. magnatum symbiotic structures is supported by molecular analysis. When diagnostic morphological traits appear only occasionally, as a result of ageing or of particular edaphic conditions, only molecular markers such as the species-specific ITS primers designed here ensure reliable typing of T. magnatum mycorrhizae for the purpose of controlling and/or certifying mycorrhizal plants present on the market.

Identification and characterisation of human pathogenic filamentous fungi and susceptibility to Thymus schimperi essential oil

Twenty‐eight clinical fungal isolates were characterised by morphological (macro‐ and micro‐features and growth response at 25, 30 and 37 °C) and molecular (nuclear rDNA‐internal transcriber spacer, calmodulin, cytochrome c oxidase 1 and the largest subunit of RNA polymerase II) analyses. The clinical fungal isolates were ascribed to the following taxa: Penicillium chrysogenum, Verticillium sp., Aspergillus tubingensis, Aspergillus minutus, Beauveria bassiana and Microsporum gypseum. In addition, in vitro susceptibility testing of the isolates to conventional antifungal agents and to two chemically well‐defined chemotypes of Thymus schimperi essential oil was performed. Most of the isolates were resistant to amphotericin B (except A. minutus), and itraconazole, while terbinafine was quite active on these fungi. T. schimperi essential oil showed antifungal activity against all of the tested fungal isolates with minimal inhibitory concentration values similar or lower than those of terbinafine. Transmission electron microscopy analyses revealed that fungal growth inhibition by essential oil was accompanied by marked morphological and cytological changes.

The Polymorphism of the rDNA Region in Typing Ascocarps and Ectomycorrhizae of Truffle Species

Methods were developed to type some of the most economically important Tuber spp. (Tuber aestivum f. uncinatum, Tuber albidum, Tuber magnatum, Tuber brumale, Tuber melanosporum) and some of their mycorrhizae by the use of molecular markers. The polymorphism of the rDNA region was investigated by polymerase chain reaction (PCR) and Southern experiments on DNA isolated from ascocarps, uninoculated host roots and mycorrhizae. Using specific primer pairs, PCR amplification of the internal transcribed spacers (ITS) and intergenic spacer (IGS) of DNA isolated from fruitbodies allowed fungus discrimination only by the length or the number of the ITS and IGS amplified fragments. These results were confirmed by Southern analysis carried out on fungus DNA restricted with EcoRI and probed with the ITS fragment of T. brumale: a specific banding pattern for each species tested was evident. The same analyses were then performed on mycorrhizal root tips and inoculated host plant roots. Each fungus-host plant interaction showed a specific pattern due to the combination of traits of the two partners. It is concluded that rDNA region is a suitable molecular marker to characterize both ascocarps and mycorrhizae of truffle species by PCR and/or Southern analysis.

Studio Comparativo della Struttura e del Ciclo Biologico di Due Diatomee di Acqua Dolce: Navicula Minima Grun. E Navicula Seminulum Grun: II. Struttura e Ciclo Biologico: di Navicula Seminulum Grun. Coltivata In Vitro

Abstract Comparative study of the structure and of the biological cycle of two fresh water diatoms: « Navicula minima » Grun. and « Navicula seminulum » Grun. I. Structure and biological cycle of « Navicula minima » Grun. cultivated « in vitro ». — The Navicula minima Grun. was isolated in a clonal culture using cultural soil agarized by Tanada. To accomplish the biometrical and structural study of the frustules, the cleaning was performed with concentrated sulphuric acid and sodium nitrate. The observations of the chromatophores, the nucleus, and the ribosomes were executed with a fluorescent microscope using Acridine orange. Before to expose the experimental part some descriptions made by various researchers were reported, emphasizing the existence of considerable differences among those in the same species. The structure of the frustule is that which is typical of all the Naviculae in the species under examination a narrow axial area is present and a central area rather enlarged transversally. The wall...

Struttura di alcune valve teratologiche di Navicula gallica (W. smith) Van Heurck

Abstract Structure of some teratologic valves of Navicula gallica (W. Smith) Van Heurck.—The more frequent alterations of some structural elements of N. gallica valves cultivated in vitro for a few years are described: the valvar contour, the axial area, the raphe, the shape and size of the central nodule, the pores and spinulae. It is pointed out that the centre-axial pores are orientated towards the axial area regardless of their shape and position on the valve plane and independently of the presence or absence of the raphe. Aside from a few alterations tied strictly to the structure of the species in question, one may observe that some characters undergo deformations according to models already found for other species of the same genus and even of different genera.

Comportamento Di Un Carattere Teratologico Comparso in Navicula Minima Grun

Abstract Behaviour of a teratological character present in «Navicula minima» Grun. — A teratological form with curved cells like the kidneys has been isolated from a culture of Navicula minima Grun, to follow the behaviour during the biological cycle. Alternately varied cells in the morphology of the frustules appeared in the descendants, deriving from a modification more or less evident in the initial teratological character. The main cause of this phenomenon can be found in the normalization process of the frustules that has been put in relation to a probable plasticity of the cellular Silicon walls. The cells, even though more or less deformed, have given origin to auxozygotes which, having terminated their growth, have formed perfectly normal frustules.

Alcune Forme Teratologiche Comparse in Colture di Navicula Minima Grun. e Navicula Seminulum Grun

Abstract Some teratological forms present in cultures of «Navicula minima» Grun. and «Navicula seminulum» Grun. — The teratological frustules of the Navicula minima and of the Navicula seminulum which appeared in the old cultures on the agarized soil have examined at the electron microscope. The alterations are particularly concerned with the contour of the valve, the position, the size and the number of the central and polar nodules, the axial area often fragmented like the raphe and the striae are oriented variously on the plane of the valve. The causes of such alterations can be found in the nutritional conditions and the unfavorable environments. The examined teratological forms, however bizzar and numerous have in common the characteristic of presenting their structure in relation to the distribution of the 2ones of major thickness of the walls; which are the first to appear in the initial formation of the new thecae; for this reason it is in this moment that the definitive, normal or teratological s...

La micorrizazione di alcuni cloni micropropagati di Populus alba L. con Tuber magnatum Pico

Abstract Mycorrhization of some micropropagated clones of Populus alba L. with Tuber magnatum Pico. - Plants micropropagated from clones of white poplar (Populus alba L.) were mycorrhized with Tuber magnatum Pico using three inoculation techniques: the sporal suspension method, the method of putting mycorrhized root framgments in contact with roots of plants to be mycorrhized and the method of root transmission using mother plants. The mycorrhization methods were then compared. The last two methods gave the best results. An analytical description is reported of the morphological, anatomical and biometrical structures of the mycorrhizae. Some of the clones showed a great capacity to be mycorrhized with the prized white truffle.

Revisione Critica di Navicula Nigrii, Navicula Casertana, Pinnularia Passerinii, Stauroneis Verbania e Synedra Juliana de Notaris

Abstract Critical revision of «Navicula nigrii», «Navicula casertana», «Pinnularia passerinii», «Stauroneis verbania» and «Synedra juliana» De Notaris. — Certain species of diatoms set up by DE NOTARIS in the last Century have been re-examined, using the same studying material as the author. Such revisions were found necessary in that the original descriptions were not equipped with any drawing for which the most recent authors (MILLS 1932 and HUSTEDT 1962) expressed their doubts as to the real identity of such diatoms. Once individualized the species to he studied, a new description was brought to effect on the basis of biometric characters and observed morphologics with the optical microscope and in some cases with the electronical one. In this way it has been possible to identify the Navicula nigrii De Notaris with the Navicula minima Grun.; the Navicula casertana De Notaris with the Cymbella microcephala Grun.; the Pinnularia passerinii De Notaris with the Navicula cincta (Ehr.) KUtz.; the Stauroneis ...

Studio Comparativo della Struttura e del Ciclo Biologico di Due Diatomee di Acqua Dolce: Navicula Minima Grun. E Navicula Seminulum Grun.: III. Esame Dei Caratteri di Navicula Minima Grun. E di Navicula Seminulum Grun

Abstract Comparative study of the structure and of the biological cycle of two fresh water diatoms: « Navicula minima » Grun. and « Navicula seminulum » Grun. III. Examination of the characteristics of « N. minima » Grun. and « N. seminulum » Grun. — After studing separately the Navicula minima Grun. and the Navicula seminulum Grun. the various characteristics of the two have been compared and contrasted for purpose of classification. The form and dimentions of the frustules, the density and the structure of the streaks, the structure of the walls, the life circle, aspects of their growths, and some anomalies, most especially, as regards the streaks were examined. It was found the among such numerous characteristics, only one, that is, the presence of the streaks formed by double rows of pores in N. seminulum rather than of a simple file as in N. minima makes one thinks that, in spite of strong similarities existing between these two Naviculae, they are to be regarded as belonging to e different systemati...