Colonization of intravenous catheters by coagulase-negative staphylococci was followed by scanning electron microscopy. Regular sampling of specimens demonstrated adhesion of the staphylococci to the catheter surface followed by cell proliferation, possible breakdown of catheter components, and production of a slimy material covering the bacterial colonies. The implications of these findings with reference to nosocomial infections of prosthetic devices are discussed.

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A group of 25 strains of Aspergillus spp., most of them known for producing aflatoxins or other mycotoxins, was cultivated on Aspergillus differential medium, containing ferric ions. Two red pigments produced by the test-sensitive strains have been isolated and identified as ferriaspergillin (1) and ferrineoaspergillin (2). The formation of the yellow pigmentation on ADM is related to the production of aspergillic acid (3) or neoaspergillic acid (4).

Biology, taxonomy, pathogenicity and control of plant disease inducing actinomycetes are reviewed. Recent progress in the study of potato, sweet potato, blueberry and fruit and forest tree diseases is illustrated. The role in potato scab pathogenesis of the newly discovered phytotoxins, thaxtomins, is discussed.Abbreviations: ATCC = American Type Culture Collection, Rockville, Md, USA; IMRU = Institute of Microbiology, Rutgers University, NJ, USA; ISP = International Streptomyces Project; PCNB = pentachloronitrobenzene; 3,5-D = 3,5-dichlorofenoxyacetic acid.

This is the first time that an artificial neural network has been used to predict fumonisin accumulation in maize: the prediction has been shown to have the potential for the development of a new approach for the rapid cataloging of grain lots.

A mixed microbial culture degrading fumonisin B l was obtained from soil samples using an enrichment culture procedure. A bacterial isolate from the enrichment culture (strain NCB 1492) degraded fumonisin B1 after incubation for 3 h, as indicated by TLC and HPLC analysis. On the basis of the sequence analysis of 16S rDNA, strain NCB 1492 was related to the Delftia/Comamonas group. Thin-layer chromatographic analysis indicated the presence of metabolites in the NCB 1492 culture filtrates after degradation of fumonisin B1 supplied as sole carbon and nitrogen source in phosphate buffer. Four metabolites were identified by mass spectrometry analysis.

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Red clover (Trifolium pratense) and Ladino clover (Trifolium repens) plants showing phytoplasma-associated symptoms (yellowing/reddening, virescence and phyllody) have been recovered in Friuli-Venezia Giulia, Italy. Using AluI RFLP analysis of PCR amplified 16S rDNA we showed that the disease can be caused independently by two phylogenetically distinct phytoplasmas. One of them showed the very typical 16S rDNA RFLP pattern of the agent of Clover Phyllody in Canada (CCPh). The 16S rDNA of the other phytoplasma (Italian Clover Phyllody phytoplasma, ICPhp) has been PCR amplified, cloned and sequenced. The sequence revealed high similarity (>98%) with phytoplasmas belonging to the X disease cluster, which includes organisms not reported to cause phyllody on their hosts. The analysis by AluI RFLP of the PCR amplified pathogen 16S rDNA from other herbaceous plants (Crepis biennis, Taraxacum officinale, Leucanthemum vulgare) collected nearby with phytoplasma-associated symptoms showed similar patterns. Southem blot hybridization of their EcoRI digested total DNA revealed identical RFLP patterns, suggesting that the causative agent may be the same organism.