Integrons are genetic elements known for their role in the acquisition and expression of genes conferring antibiotic resistance. Such acquisition is mediated by an integron-encoded integrase, which captures genes that are part of gene cassettes. To test whether integrons occur in environments with no known history of antibiotic exposure, PCR primers were designed to conserved regions of the integrase gene and the gene cassette recombination site. Amplicons generated from four environmental DNA samples contained features typical of the integrons found in antibiotic-resistant and pathogenic bacteria. The sequence diversity of the integrase genes in these clones was sufficient to classify them within three new classes of integron. Since they are derived from environments not associated with antibiotic use, integrons appear to be more prevalent in bacteria than previously observed.

A total of 220 cell envelope-associated proteins were successfully extracted and separated from Trichoderma reesei mycelia actively synthesizing and secreting proteins and from mycelia in which the secretion of proteins are low. Altogether 56 spots were examined by nanoelectrospray tandem mass spectrometry and amino acid sequence was obtained for 32 spots. From these, 20 spots were identified by Advanced BLAST searches against all databases available to BLAST. The most abundant protein in both types of mycelia was HEX1, the major protein in Woronin body, a structure unique to filamentous fungi. Other proteins identified were vacuolar protease A, enolase, glyceraldehyde-3-phosphate dehydrogenase, transaldolase, protein disulfide isomerase, mitochondrial outer membrane porin, diphosphate kinase and translation elongation factor beta. Partial short amino acid sequence obtained from some proteins did not allow them to be assigned to a specific protein in the database by BLAST search. In some cases, the tandem mass spectrometry spectra were too complicated to be able to assign an amino acid sequence with certainty. The number of spots (12) giving a clear signal but finding no match in the databases suggests that a majority of proteins associated with a filamentous fungal cell wall, are novel. Some technical problems related to protein isolation are also discussed.

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Culture filtrates and mycelial extracts of two mycoparasitic Trichoderma species were tested for the presence of lectins, by haemagglutination with human and marsupial erythrocytes. In Trichoderma viride, haemagglutinating activity was present in both mycelial extracts and culture filtrate. While secreted lectins were only detected after 6 days of growth, the presence of mycelium-associated lectins was first noted in 3-day-old cultures. Agglutinating activity was also demonstrated in the mycelium of 6-, 9- and 13-day-old cultures of Trichoderma harzianum. In this species, however, lectins were not secreted. In all instances, haemagglutination was inhibited by N-acetylgalactosamine and related sugars. This is the first report on the occurrence of lectins in Trichoderma spp.

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