| 1. |
- Löfmark, Sonja, et al.
(författare)
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Clindamycin-induced enrichment and long-term persistence of resistant Bacteroides spp. and resistance genes
- 2006
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Ingår i: Journal of Antimicrobial Chemotherapy. - : Oxford University Press (OUP). - 0305-7453 .- 1460-2091. ; 58:6, s. 1160-1167
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The aim was to study the long-term consequences of 1 week clindamycin administration regarding selection and persistence of resistance, resistance determinants and diversity of the Bacteroides spp. in the intestinal microflora. Methods: A total of 1306 Bacteroides isolates were collected from constitutively cultured faecal samples during a 2 year period from eight healthy volunteers. The strains were identified by biochemical and genotyping methods. MIC values were determined by the agar dilution method and presence of resistance genes was screened by real-time PCR. Results: Ecological changes in the intestinal microflora persisting up to 24 months were recorded after a 7 day clindamycin administration to four healthy volunteers. Compared to a control group, not exposed to clindamycin, an enrichment and stabilization of resistant Bacteroides strains and resistance determinants were discovered up to 2 years after clindamycin exposure. Conclusions: The results indicate that even a short-term antibiotic administration can cause long-term alterations in the commensal microbiota of individual subjects, detectable 2 years after dosing. The recorded selection and persistence of resistant strains and resistance genes, illustrates the importance of increasing our knowledge of the role of the abundant intestinal microbial community as a reservoir for spread of resistance.
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| 2. |
- Arup, Ulf, et al.
(författare)
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Professor Ingvar Kärnfelt - a birthday tribute
- 2009
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Ingår i: The Lichenologist. - Cambridge : Cambridge University Press. - 0024-2829 .- 1096-1135. ; 41:5, s. 453-456
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- On 19 July 2009 Ingvar Kärnefelt celebrated his 65th birthday. This could have meant that we, his former students, would be celebrating him in his retirement from his position as head of the Biological Museums at Lund University. We are grateful that this is not the case, as Ingvar will carry on, probably for at least one or two more years. Instead, we celebrate Ingvar because he is the main reason for all of us having studied lichenology in Lund. This special issue of The Lichenologist is dedicated to him as a birthday tribute in honour of his long and fruitful lichenological career. The main authors of all the papers in this issue are former students of Ingvar. For several of us he has not only acted as supervisor but later also as the director of the Botanical Museum where we meet him in our daily work.
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| 3. |
- Sjögren, M., et al.
(författare)
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Antifouling activity of brominated cyclopeptides from the marine sponge Geodia barretti
- 2004
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Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 67:3, s. 368-372
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we show the potent antifouling effects of two compounds, barettin (cyclo[(6-bromo-8-entryptophan)arginine]) (1), isolated as a Z/E mixture (87/13), and 8,9-dihydrobarettin (cyclo[(6-bromotryptophan)arginine]) (2), isolated from the marine sponge Geodia barretti. The compounds were isolated guided by their ability to inhibit the settlement of cyprid larvae of the barnacle Balanus improvisus, and their structures were determined by means of mass spectrometry, NMR, and quantitative amino acid analysis. The activities of these brominated diketopiperazine-like cyclic dipeptides are in the range of antifouling agents in use today, as shown by their EC50 values of 0.9 and 7.9 muM, respectively. However, contrary to today's antifouling agents, the effects of barettin and 8,9-dihydrobarettin are nontoxic and reversible. A small set of synthetic analogues, including L-arginine, L-tryptophan, 5-bromo-D,L-tryptophan, 6-bromo-D,L-tryptophan, and 6-fluoro-D,L-tryptophan, were tested for possible structure-activity relationships. None of these compounds showed any effect at a concentration of 10 muM. We hypothesize that the isolated compounds are part of the sponge's chemical defense to deter fouling organisms. This theory is supported by the fact that barettin is found in water exposed to living specimens of G. barretti in concentrations that completely inhibit barnacles from settling.
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| 4. |
- Johnson, Ann-Louise, et al.
(författare)
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Synthesis of barettin
- 2004
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Ingår i: Tetrahedron. - : Elsevier BV. - 0040-4020 .- 1464-5416. ; 60:4, s. 961-965
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Tidskriftsartikel (refereegranskat)abstract
- The indole alkaloid barettin (with bromine in 6-position), isolated from the marine sponge Geodia Barretti, has been synthesised via a Horner-Wadsworth-Emmons type reaction from 6-bromoindole-3-carboxaldehyde to introduce the dehydro-functionality. Subsequent deprotection and cyclisation afforded the natural product in Z-conformation.
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