Leptospira species colonize a significant proportion of rodent populations worldwide and produce life-threatening infections in accidental hosts, including humans. Complete genome sequencing of Leptospira interrogans serovar Copenhageni and comparative analysis with the available Leptospira interrogans serovar Lai genome reveal that despite overall genetic similarity there are significant structural differences, including a large chromosomal inversion and extensive variation in the number and distribution of insertion sequence elements. Genome sequence analysis elucidates many of the novel aspects of leptospiral physiology relating to energy metabolism, oxygen tolerance, two-component signal transduction systems, and mechanisms of pathogenesis. A broad array of transcriptional regulation proteins and two new families of afimbrial adhesins which contribute to host tissue colonization in the early steps of infection were identified. Differences in genes involved in the biosynthesis of lipopolysaccharide O side chains between the Copenhageni and Lai serovars were identified, offering an important starting point for the elucidation of the organism's complex polysaccharide surface antigens. Differences in adhesins and in lipopolysaccharide might be associated with the adaptation of serovars Copenhageni and Lai to different animal hosts. Hundreds of genes encoding surface-exposed lipoproteins and transmembrane outer membrane proteins were identified as candidates for development of vaccines for the prevention of leptospirosis.

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The new benzoxazole derivative nataxazole was isolated from Streptomyces sp. (strain Tü 6176). Nataxazole is related in structure to the potent antitumor compounds UK-1 and AJI9561 and showed similar strong growth inhibitory activity against various human tumor cell lines.Keywords benzoxazole derivative, HPLC-diode array screening, antitumor activity, structure elucidation, Streptomyces Freshly isolated actinomycetes from soils collected in the environment of Natal, Rio Grande do Norte, Brasil, were grown in submerged culture in different media, and extracts prepared from mycelia and culture filtrates at various fermentation times were screened by HPLC-diode array analysis in combination with an in-house developed HPLC-UV-Vis database [2] to detect novel secondary metabolites. Strain Tü 6176 was found to be of special interest as it gave a mycelium extract that contained a dominant peak in the HPLC profile with a retention time of 14.8 minutes in standard reversed-phase gradient elution [2]. Its characteristic UV-visible spectrum (Fig. 1) differed from that of 867 reference compounds stored in the HPLC-UVVis database. Due to the collection site and its chemical structure (Fig. 2), the compound was named nataxazole (1).Strain Tü 6176 (RN-13.5) was isolated from a soil sample collected at Mata da Estrela, RN, Brazil. It was examined for a number of key properties known to be of value in streptomycete systematics. The presence of LLdiaminopimelic acid in the peptidoglycan [3] together with

The winged helix transcription factors HNF-3/FKH (forkhead homologs) activate endodermal-derived and acute-phase gene expression and control gut development in Drosophila. Trefoil factor family (TFFs) peptides are vertebrate products secreted by mucin-producing epithelial cells of the gastrointestinal tract involved in restitution and repair of the mucosa. They are positively regulated in ulcerative and neoplastic conditions. We describe a consensus sequence in human and rodent TFF promoters close to the TATAA box showing striking similarity to the binding site of the HNF-3/FKH family. In gel retardation assays, HNF-3 alpha and beta bound predominantly to the site in TFF1 (formerly pS2) and, to a lesser extent, to the sites in TFF2 or TFF3. Mutations generated in this motif severely impaired transcription of TFF1 reporter genes. Cotransfection with expression vectors of HNF-3alpha and beta, but not the related HFH 11A and B, specifically activated the wild-type TFF1 reporter genes. Activation of endogenous expression of TFF1 by HNF-3 alpha and beta gene products was more than 1000 fold in the pancreatic cell line Capan-2 and fivefold in the gastric cell line MKN-45, whereas the intestinal cell lines HUTU 80 and HT-29 displayed no effect. Thus, HNF-3/FKH factors contribute causally to cell-specific regulation of TFF genes and may explain the acute-phase response of TFF peptides.

Streptomyces cinnamomeus Tü89 secretes a 30-kDa esterase and a 50-kDa lipase. The lipase-encoding gene, lipA, was cloned from genomic DNA into Streptomyces lividans TK23 with plasmid vector pIJ702. Two lipasepositive clones were identified; each recombinant plasmid had a 5.2-kb MboI insert that contained the complete lipA gene. The two plasmids differed in the orientation of the insert and the degree of lipolytic activity produced. The lipA gene was sequenced; lipA encodes a proprotein of 275 amino acids (29,213 Da) with a pI of 5.35. The LipA signal peptide is 30 amino acids long, and the mature lipase sequence is 245 amino acids long (26.2 kDa) and contains six cysteine residues. The conserved catalytic serine residue of LipA is in position 125. Sequence similarity of the mature lipases (29% identity, 60% similarity) was observed mainly in the N-terminal 104 amino acids with the group II Pseudomonas lipases; no similarity to the two Streptomyces lipase sequences was found. lipA was also expressed in Escherichia coli under the control of lacZ promoter. In the presence of the inducer isopropyl-␤-D-thiogalactopyranoside (IPTG), growth of the E. coli clone was severely affected, and the cells lysed in liquid medium. Lipase activity in the E. coli clone was found mainly in the pellet fraction. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, three additional protein bands of 50, 29, and 27 kDa were visible. The 27-kDa protein showed lipolytic activity and represents the mature lipase; the 29and 50-kDa forms showed no activity and very probably represent the unprocessed form and a dimeric misfolded form, respectively. For higher expression of lipA in S. lividans, the gene was cloned next to the strong aphII promoter. In contrast to the lipA-expressing E. coli clone, S. cinnamomeus and the corresponding S. lividans clone secreted only an active protein of 50 kDa. The lipase showed highest activity with C 6 and C 18 triglycerides; no activity was observed with phospholipids, Tween 20, or p-nitrophenylesters. Upstream of lipA and in the same orientation, an open reading frame, orfA, is found whose deduced protein sequence (519 amino acids) shows similarity to various membrane-localized transporters. Downstream of lipA and in the opposite orientation, the open reading frame orfB (encoding a 199-amino-acid protein) is found, which shows no conspicuous sequence similarity to known proteins, other than an NAD and flavin adenine dinucleotide bindingsite sequence.