| 1. |
- Nordberg Karlsson, Eva, et al.
(författare)
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Differences and similarities in enzymes from the neopullulanase subfamily isolated from thermophilic species
- 2008
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Ingår i: Biologia. - : Springer Science and Business Media LLC. - 0006-3088 .- 1336-9563. ; 63:6, s. 1006-1014
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Konferensbidrag (refereegranskat)abstract
- Six glycoside hydrolase (GH) family 13 members, classified under the polyspecific neopullulanase subfamily GH13_20 (also termed cyclomaltodextrinase) were analysed. They originate from thermophilic bacterial strains (Anoxybacillus flavithermus, Laceyella sacchari, and Geobacillus thermoleovorans) or from environmental DNA, collected after in situ enrichments in Icelandic hot springs. The genes were isolated following the CODEHOP consensus primer strategy, utilizing the first two of the four conserved sequence regions in GH13. The typical domain structure of GH13 20, including an N-terminal domain (classified as CBM34), the catalytic module composed of the A- and B- domains, and a C- terminal domain, was found in five of the encoded enzymes (abbreviated Amy1, 89, 92, 98 and 132). These five enzymes degraded cyclomaltodextrins (CDs) and starch, while only three, Amy92 (L. sacchari), Amy98 (A. flavithermus) and Amy132 (environmental DNA), also harboured neopullulanase activity. The L. sacchari enzyme was monomeric, but with CD as the preferred substrate, which is an unusual combination. The sixth enzyme (Amy29 from environmental DNA), was composed of the ABC-domains only. Preferred substrate for Amy29 was pullulan, which was degraded to panose, and the enzyme had no detectable activity on CDs. In addition to its different activity pro. le and domain composition, Amy29 also displayed a different conservation (LPKF) in the fifth conserved region (MPKL) proposed to identify the subfamily. All enzymes had apparent temperature optima in the range 50-65 degrees C, while thermostability varied, and was highest for Amy29 with a half-life of 480 min at 80 degrees C. Calcium dependent activity or stability was monitored in four enzymes, but could not be detected for Amy29 or 98. Tightly bound calcium can, however, not be ruled out, and putative calcium ligands were conserved in Amy98.
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| 2. |
- Pettersson, Jenny, et al.
(författare)
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NMR metabolomic analysis of fecal water from subjects on a vegetarian diet
- 2008
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Ingår i: Biological and Pharmaceutical Bulletin. - : Pharmaceutical Society of Japan. - 0918-6158 .- 1347-5215. ; 31:6, s. 1192-1198
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Tidskriftsartikel (refereegranskat)abstract
- A vegetarian diet rich in phytochemicals may prevent colon carcinogenesis by affecting biochemical processes in the colonic mucosa. Compounds passing the digestive system reaching the colon could potentially be detected in fecal water. We previously reported that intact fecal water samples from human volunteers significantly decreased prostaglandin production and COX-2 protein expression in colonic cells. The aim with the present study was to further study the composition of the fecal waters, using NMR spectroscopy and multivariate data analysis, and to trace the COX-2 inhibiting activity. Intact fecal water samples and fractions thereof were analyzed for their ability to inhibit prostaglandin E2 production in the human colon cell line HT-29. The majority of the tested aqueous phases derived from intact fecal water showed ability to inhibit prostaglandin production in cells (13.8+/-1.34% inhibition, p=0.01). NMR analysis indicated the presence of significant quantities of amino acids and fatty acids. Major metabolites included; acetic acid, butanoic acid, propanoic acid, glutamic acid and alanine. Smaller amounts of glycine and fumaric acid, which are known to have anti-inflammatory and anti-tumorigenic properties, were also detected. This study describes for the first time NMR metabolomic analysis of fecal water from subjects on a vegetarian diet.
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| 3. |
- Pettersson, Jenny, et al.
(författare)
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The flavouring phytochemical 2-pentanone reduces prostaglandin production and COX-2 expression in colon cancer cells
- 2008
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Ingår i: Biological and Pharmaceutical Bulletin. - : Pharmaceutical Society of Japan. - 0918-6158 .- 1347-5215. ; 31:3, s. 534-537
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Tidskriftsartikel (refereegranskat)abstract
- Many phytochemicals found in the diet may prevent colon carcinogenesis by affecting biochemical processes in the colonic mucosa. Inflammation and subsequent elevation of the enzyme cyclooxygenase-2 (COX-2) are two such factors involved in the development of colon cancer, and inhibition of these processes could be important targets for chemoprevention. We have previously shown COX-2 inhibitory activity locally in the colon; e.g. in human fecal water from a group of vegetarians. In this study we focus on 2-pentanone, a frequently occurring compound in common foods such as banana and carrot. The aim was to study the inhibitory effects on prostaglandin production and COX-2 protein expression in tumour necrosis factor-alpha stimulated colon cancer cells (HT29) by radioimmunoassay and Western blotting. 2-Pentanone inhibited both prostaglandin production and COX-2 protein expression in human colon cancer cells. A concentration of 400 mumol/l 2-pentanone inhibited the prostaglandin production by 56.9+/-12.9% which is in the same range as the reference compound NS398 (59.8+/-7.6%). The two highest concentrations of 2-pentanone were further analyzed by Western blot, and 400 micromol/l and 200 micromol/l 2-pentanone resulted in a 53.3+/-9.6% and +/-27.1% reduction of the COX-2 protein levels respectively. Further studies on flavouring compounds, for example 2-pentanone, as colon cancer chemopreventives would be very valuable, and such results may contribute to future dietary recommendations.
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| 4. |
- Ruhaak, Lucia Renee, et al.
(författare)
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Evaluation of the Cyclooxygenase Inhibiting Effects of Six Major Cannabinoids Isolated from Cannabis sativa
- 2011
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Ingår i: Biological and Pharmaceutical Bulletin. - : Pharmaceutical Society of Japan. - 0918-6158 .- 1347-5215. ; 34:5, s. 774-778
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Tidskriftsartikel (refereegranskat)abstract
- Cyclooxygenase enzymes (COX-1 and COX-2) catalyse the production of prostaglandins from arachidonic acid. Prostaglandins are important mediators in the inflammatory process and their production can be reduced by COX-inhibitors. Endocannabinoids, endogenous analogues of the plant derived cannabinoids, occur normally in the human body. The Endocannabinoids are structurally similar to arachidonic acid and have been suggested to interfere with the inflammatory process. They have also been shown to inhibit cancer cell proliferation. Anti-inflammatory effects of cannabinoids and endocannabinoids have been observed, however the mode of action is not yet clarified. Anti-inflammatory activity (i.e., inhibition of COX-2) is proposed to play an important role in the development of colon cancer, which makes this subject interesting to study further. In the present work, the six cannabinoids tetrahydrocannabinol (Delta(9)-THC), tetrahydrocannabinolic acid (Delta(9)-THC-A), cannabidiol (CBD), cannabidiolic acid (CBDA), cannabigerol (CBG) and cannabigerolic acid (CBGA), isolated from Cannabis sativa, were evaluated for their effects on prostaglandin production. For this purpose an in vitro enzyme based COX-1/COX-2 inhibition assay and a cell based prostaglandin production radioimmunoassay were used. Cannabinoids inhibited cyclooxygenase enzyme activity with IC50 values ranging from 1.7.10(-3) to 2.0.10(-4) M.
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