| 1. |
- Aqueveque, Pedro, et al.
(författare)
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Bioactive compounds isolated from submerged fermentations of the Chilean fungus Stereum rameale
- 2015
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Ingår i: Zeitschrift fuer Naturforschung. Section C: A Journal of Biosciences. - : Walter de Gruyter GmbH. - 0939-5075. ; 70:3-4, s. 97-102
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Tidskriftsartikel (refereegranskat)abstract
- Liquid fermentations of the fungus Stereum rameale (No 2511) yielded extracts with antibacterial -activity. The antibacterial activity reached its peak after 216 h of stirring. Bioassay-guided fractionation methods were employed for the isolation of the bioactive metabolites. Three known compounds were identified: MS-3 (1), vibralactone (2) and vibralactone B (3). The three compounds showed antibacterial activity as a function of their concentration. Minimal bactericidal concentrations (MBC) of compound 1 against Gram-positive bacteria were as follows: Bacillus cereus (50 mu g/mL), Bacillus subtilis (10 mu g/mL) and Staphylococcus aureus (100 mu g/mL). Compounds 2 and 3 were active only against Gram-negative bacteria. The MBC of compound 2 against Escherichia coli was 200 mu g/mL. Compound 3 inhibited significantly the growth of E. coli and Pseudomonas aeruginosa, with MBC values of 50 and 100 mu g/mL, respectively.
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| 2. |
- Farhat, Wissam, et al.
(författare)
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Biocatalysis for terpene-based polymers
- 2019
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Ingår i: Zeitschrift für Naturforschung C - A Journal of Biosciences. - : WALTER DE GRUYTER GMBH. - 0939-5075 .- 1865-7125. ; 74:3-4, s. 90-99
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Tidskriftsartikel (refereegranskat)abstract
- Accelerated generation of bio-based materials is vital to replace current synthetic polymers obtained from petroleum with more sustainable options. However, many building blocks available from renewable resources mainly contain unreactive carbon-carbon bonds, which obstructs their efficient polymerization. Herein, we highlight the potential of applying biocatalysis to afford tailored functionalization of the inert carbocyclic core of multicyclic terpenes toward advanced materials. As a showcase, we unlock the inherent monomer reactivity of norcamphor, a bicyclic ketone used as a monoterpene model system in this study, to afford polyesters with unprecedented backbones. The efficiencies of the chemical and enzymatic Baeyer-Villiger transformation in generating key lactone intermediates are compared. The concepts discussed herein are widely applicable for the valorization of terpenes and other cyclic building blocks using chemoenzymatic strategies.
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| 3. |
- Rahmani, Rizan, et al.
(författare)
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SPME collection and GC-MS analysis of volatiles emitted during the attack of male Polygraphus poligraphus (Coleoptera, Curcolionidae) on Norway spruce
- 2015
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Ingår i: Zeitschrift für Naturforschung C - A Journal of Biosciences. - : Walter de Gruyter GmbH. - 0939-5075 .- 1865-7125. ; 70:9-10, s. 265-273
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Tidskriftsartikel (refereegranskat)abstract
- Tree mortality caused by bark beetles has increased in recent decades in both Europe and North America. In a large recent outbreak in central Sweden the bark beetle Polygraphus poligraphus was often found together with the spruce bark beetle Ips typographus in killed trees. To increase the understanding of the aggregation behavior of P. poligraphus we used solid phase microextraction (SPME) to collect volatile organic compounds (VOCs) released from single P. poligraphus males, with and without added females, colonizing Norway spruce stem sections and analyzed the sampled compounds by combined gas chromatography and mass spectrometry (GC-MS). High amounts of terpinen-4-ol, a substance found in the hindguts of P. poligraphus males in earlier studies, were released by colonizing males. The emission of both enantiomers of terpinen-4-ol was monitored by GC-MS over time as the males aged in the absence and presence of females. Single males emitted (R)-(-)-terpinen-4-ol for up to 60 days in high enantiomeric purity but the enantiomeric excess (ee) varied between males, and also for the same individual, over time from 96.3% to 99.3% ee. In the presence of females, males also emitted terpinen-4-ol for up to 50 days but now in lower amounts and with lower enantiomeric purity varying from 67.7% ee to 99.3% ee. Small quantities of other volatile compounds were emitted from the colonizing beetles including cis-and trans-4-thujanol, both of which were previously shown to be present in the hindguts of males. In earlier studies frontalin was found to attract P. poligraphus, but in our study it was not identified among emitted compounds from colonizing beetles.
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| 4. |
- Zhao, Yadong, et al.
(författare)
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Ascidian bioresources : common and variant chemical compositions and exploitation strategy examples of Halocynthia roretzi, Styela plicata, Ascidia sp and Ciona intestinalis
- 2016
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Ingår i: Zeitschrift für Naturforschung C - A Journal of Biosciences. - : Walter de Gruyter GmbH. - 0939-5075 .- 1865-7125. ; 71:5-6, s. 165-180
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Tidskriftsartikel (refereegranskat)abstract
- To explore abundant marine ascidian bioresources, four species from two orders have been compared in their chemical compositions. After a universal separation of the animal body into two fractions, all tunics have been found rich in carbohydrate contents, while all inner body tissues are richer in proteins. Cellulose is present almost exclusively in the tunics and more in the order Stolidobranchia, while more sulfated polysaccharides are present in Phlebobranchia species. Almost all proteins are collagens with a high essential amino acid index and high delicious amino acid (DAA) content. All fractions also have high contents of good-quality fatty acids and trace minerals but low toxic element contents, with different sterols and glycosaminoglycans. There are species-specific characteristics observed for vanadium accumulation and sterol structures which are also meaningful for ascidian chemotaxonomy and resource exploitation. It is suggested that in addition to the present utilizations of tunics for cellulose production and of some species' inner body tissues as human food, one should explore all species' inner body tissues as human foods and all tunics as food or animal feed with the contained cellulose as dietary fiber. Collagens, sulfated polysaccharides, glycosaminoglycans, sterols and trace elements could be explored as byproducts for, e.g. pharmaceutical and chemical industries.
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