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| 2. |
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| 3. |
- Sandborgh-Englund, G, et al.
(författare)
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Pharmacokinetics of Triclosan in man.
- 2002
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Ingår i: JOURNAL OF DENTAL RESEARCH. - 0022-0345. ; 81, s. A137-A137
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Apoga, D, et al.
(författare)
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Relationship between production of the phytotoxin prehelminthosporol and virulence in isolates of the plant pathogenic fungus Bipolaris sorokiniana
- 2002
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Ingår i: European Journal of Plant Pathology. - 0929-1873. ; 108:6, s. 519-526
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Tidskriftsartikel (refereegranskat)abstract
- A gas chromatographic method was developed to quantify the phytotoxin prehelminthosporol, which is a sesquiterpene metabolite of the plant pathogen Bipolaris sorokiniana. The toxin was extracted from mycelium or culture filtrates, pre-cleaned using solid phase extraction, and analyzed by gas chromatography as a trimethylsilyl-derivative. The detection limit of the method was 5 ng mul(-)1 (signal to noise ratio 4 : 1) which corresponds to ca. 15 ng prehelminthosporol per mg dry weight of mycelium or 15 ng prehelminthosporol per ml culture filtrate. The total amount of prehelminthosporol (mycelium plus culture filtrate) increased with cultivation time when examined in six isolates of B. sorokiniana after 6, 9, 12 and 15 days of incubation. The screening experiment of 17 isolates for prehelminthosporol production after 8 days of incubation revealed significant differences in the toxin production between the isolates. The isolates with low toxin production had lower virulence towards barley roots compared to those with higher production of the toxin. However, the virulence did not increase with prehelminthosporol level among the high producing isolates. Prehelminthosporol was also analyzed in a number of related Bipolaris and Drechslera species. In addition to B. sorokiniana, three out of six Bipolaris species (B. setariae, B. zeicola, B. victoriae) produced prehelminthosporol, which indicates that ability to produce prehelminthosporol is conserved among closely-related Bipolaris species.
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| 5. |
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| 6. |
- Ek, H., et al.
(författare)
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Determination of N-15-labeled ammonium and total nitrogen in plant and fungal systems using mass-spectrometry
- 1990
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Ingår i: Journal of Microbiological Methods. - 1872-8359. ; 11:3-4, s. 169-176
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Tidskriftsartikel (refereegranskat)abstract
- A selected ion-monitoring method to measure 15N-labelled ammonia in biological samples was improved to simplify sample handling, to obviate interference from ammonia due to the decomposition of glutamine and to allow the determination of total N. Ammonia is derivatized with pentafluorobenzoylchloride to yield pentafluorobenzamide which is analysed by gas chromatography/mass spectrometry after clean-up using disposable silicic acid columns. The sensitivity achieved when operating in the negative ion-chemical ionization mode was somewhat higher than when using electron-impact ionization. Use of methyl amine as an internal standard improved the accuracy and precision of the measurements. The method was applied to samples taken from an intact ectomycorrhizal system fed with ISN-labelled ammonium and used to determine patterns of N assimilation into ammonium, free amino acids and macromolecular compounds.
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| 7. |
- Finlay, R.D., et al.
(författare)
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Mycelial uptake, translocation and assimilation of N-15-labeled nitrogen by ectomycorrhizal Pinus sylvestris plants
- 1990
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Ingår i: Agriculture, Ecosystems & Environment. - 1873-2305. ; 28:1-4, s. 133-137
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Tidskriftsartikel (refereegranskat)abstract
- Mycolial uptake, translocation and assimilation of 15N-labelled ammonium was followed in Pinus sylvestris plants infected with the ectomycorrhizal fungus. Paxillus involutus. The distribution of labelled compounds within the systems was examined using gas chromatography / mass spectrometry. Labelled nitrogen was incorporated into a range of free amino acids in the fungal mycelium, the principal sinks being alanine and glutamatelglutamine. Levels of 15 N enrichment declined throughout the transport pathway from 30-45% in the mycelium a~d mycorrhlzal root lips to 3-11% in the plant shoots. A significant proportion of the total assimilated nitrogen (27%) was incorporated into proteinaceous material and the proportion of label present in this fraction increased from 27% in the mycelium to 32% and 58% in the plant roots and needles respectively. The protein-incorporated amino acids showed a wider spectrum of labelling with significant amounts of 15N incorporated into valine, isoleucine, phenylalanine and lysine.
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| 8. |
- Finlay, R.D., et al.
(författare)
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Mycelial uptake, translocation and assimilation of nitrogen from N-15-labelled ammonium by Pinus sylvestris plants infected with 4 different ectomycorrhizal fungi
- 1988
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Ingår i: New Phytologist. - 1469-8137. ; 110:1, s. 59-66
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Tidskriftsartikel (refereegranskat)abstract
- The uptake and assimilation of 15N-labelled ammonium was followed in Pinus sylvestris L. plants infected with four different ectomycorrhizal fungi, Rhizopogon roseolus Fr. Suillus bovinus (Fr.) O. Kuntze, Pisolithus tinctorius (Fr.) Fr. and Paxillus involutus (Mich. ex Pers.) Cohen & Couch. Plants were grown in flat perspex observation chambers or in Petri dishes containing non-sterile peat; in each case the fungal mycelium growing from a host plant was allowed to cross a barrier and to colonize an area of peat from which roots had been excluded. Labelled ammonium was fed to the mycelium, and the shoot, root and mycelial tissues analysed for total and 15N-labelled free amino acid contents after a feeding period of 72 h. High proportions of 15N-labelled glutamate/glutamine, aspartate/asparagine, and alanine were found in the fungal mycelia of all species except Pax. involutus where labelled aspartate/asparagine was not found. Lower proportions of labelled serine, threonine, tyrosine, lysine, ornithine and arginine were also found in the mycelium. The degree of 15N enrichment declined throughout the transport pathway but between 5 and 50% of the amino acids were 15N-labelled in the plant shoots. In total, at least 2-3% of the nitrogen supplied was assimilated as labelled amino acid during the 3 day feeding period, the largest amounts of labelling occurred in glutamic acid/glutamine and aspartic acid/asparagine.
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| 9. |
- Finlay, R.D., et al.
(författare)
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Uptake, translocation and assimilation of nitrogen from 15N-labeled ammonium and nitrate sources by intact ectomycorrhizal systems of Fagus sylvatica infected with Paxillus involutus
- 1989
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Ingår i: New Phytologist. - 1469-8137. ; 113:1, s. 47-55
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Tidskriftsartikel (refereegranskat)abstract
- The uptake and assimilation of nitrogen from 15N-labelled ammonium and nitrate sources was followed in intact ectomycorrhizal systems containing Fagus sylvatica L. plants infected with the fungus Paxillus involutus (Mich. ex Pers.) Cohen & Couch. Plants were grown in flat perspex observation chambers containing non-sterile peat; the fungal mycelium growing from a host plant was allowed to cross a barrier and to colonize an area of peat from which roots had been excluded. Labelled ammonium chloride or sodium nitrate was fed to the mycelium, and the shoot, root and mycelial tissues analysed for total and 15N-labelled amino acid contents after a feeding period of 72 h. Both free and protein-incorporated amino acids were analysed. Labelled nitrogen was incorporated into a range of free amino acids, the principal sinks for assimilation being alanine, aspartate/asparagine and glutamate/glutamine. The spectrum of labelling in protein-incorporated amino acids was wider with significant incorporation into the above compounds but additional assimilation of nitrogen as glycine, valine, serine, leucine, isoleucine and arginine. In total 78% of the nitrogen assimilated was incorporated into proteinaceous material. Label was incorporated from both nitrogen sources but the levels of enrichment in most free and protein-bound amino acids were usually higher in systems supplied with ammonium than in those supplied with nitrate. The mean amount of nitrogen assimilated from nitrate was only 62% of that assimilated from ammonium.
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| 10. |
- Malmsten, M, et al.
(författare)
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Sphingomyelin from milk – characterization of liquid crystalline, liposome and emulsion properties
- 1994
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Ingår i: Journal of the American Oil Chemists Society. - 0003-021X .- 1558-9331. ; 71, s. 1021-1026
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Tidskriftsartikel (refereegranskat)abstract
- The properties of sphingomyelin obtained from bovine milk were investigated. In particular, the properties of liposomes and emulsions prepared from the sphingomyelin, as well as the liquid crystalline behaviour, were investigated and compared to those of related phosphatidylcholine systems. Like sphingomyelins from other sources, sphingomyelin from milk contains a large fraction of long and saturated acyl groups, which results in a high (35-82°C, depending on the lipid concentration) gel-to-liquid crystal transition temperature (Tc). At high sphingomyelin concentrations, a lamellar phase forms above Tc, while below Tc, a swelling gel phase is obtained. The gel phase swells to about 20 wt% water, whereas above Tc, the swelling continues to about 40 wt% water. The limiting areas per molecule are 51 and 68 Å2 below and above Tc, respectively. Sphingomyelin from milk forms liposomes readily in the presence of cholesterol. The liposomes formed have a diameter of about 100 nm, and are stable even at 0.1 M NaCl or HCl. Materials entrapped in the liposomes are released rather slowly (typically 40 % over 5 h). A comparison shows that the sphingomyelin liposomes behave similarly to those formed by phosphatidylcholine systems. Furthermore, sphingomyelin from milk forms stable o/w emulsions with soy bean oil. The size of the emulsion droplets obtained was about 200 nm. Both the size of the emulsion droplets and its dependence on electrolyte addition correlate closely with those of emulsions formed by the corresponding phosphatidylcholine system. Therefore, it is possible to use sphingomyelin as an alternative for saturated phosphatidylcholines, which may be advantageous for oral and dermal pharmaceutical applications, as well as in cosmetics.
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