| 1. |
- An, Junghwa, et al.
(author)
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Permanent Genetic Resources added to Molecular Ecology Resources Database 1 October 2009-30 November 2009
- 2010
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In: Molecular Ecology Resources. - : Wiley. - 1755-098X .- 1755-0998. ; 10:2, s. 404-408
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Journal article (peer-reviewed)abstract
- This article documents the addition of 411 microsatellite marker loci and 15 pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Acanthopagrus schlegeli, Anopheles lesteri, Aspergillus clavatus, Aspergillus flavus, Aspergillus fumigatus, Aspergillus oryzae, Aspergillus terreus, Branchiostoma japonicum, Branchiostoma belcheri, Colias behrii, Coryphopterus personatus, Cynogolssus semilaevis, Cynoglossus semilaevis, Dendrobium officinale, Dendrobium officinale, Dysoxylum malabaricum, Metrioptera roeselii, Myrmeciza exsul, Ochotona thibetana, Neosartorya fischeri, Nothofagus pumilio, Onychodactylus fischeri, Phoenicopterus roseus, Salvia officinalis L., Scylla paramamosain, Silene latifo, Sula sula, and Vulpes vulpes. These loci were cross-tested on the following species: Aspergillus giganteus, Colias pelidne, Colias interior, Colias meadii, Colias eurytheme, Coryphopterus lipernes, Coryphopterus glaucofrenum, Coryphopterus eidolon, Gnatholepis thompsoni, Elacatinus evelynae, Dendrobium loddigesii Dendrobium devonianum, Dysoxylum binectariferum, Nothofagus antarctica, Nothofagus dombeyii, Nothofagus nervosa, Nothofagus obliqua, Sula nebouxii, and Sula variegata. This article also documents the addition of 39 sequencing primer pairs and 15 allele specific primers or probes for Paralithodes camtschaticus.
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| 2. |
- Andersson, David, et al.
(author)
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Ursolic acid inhibits the formation of aberrant crypt foci and affects colonic sphingomyelin hydrolyzing enzymes in azoxymethane-treated rats
- 2008
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In: Journal of Cancer Research and Clinical Oncology. - : Springer Science and Business Media LLC. - 1432-1335 .- 0171-5216. ; 134:1, s. 101-107
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Journal article (peer-reviewed)abstract
- Ursolic acid (UA) is a pentacyclic triterpenoid, with anti-cancer and anti-inflammatory properties. Sphingomyelin (SM) hydrolysis generates lipid messengers regulating cell survival. Earlier studies showed that UA has anti-proliferative and apoptotic effects on HT29 cells, accompanied by a rapid increase in alkaline sphingomyelinase (Alk-SMase) activity. This study examines the effect of orally administered UA on the formation of aberrant crypt foci (ACF) and intestinal SMase activity in azoxymethane (AOM)-treated rats. Sprague-Dawley rats were divided into eight groups, receiving AOM or vehicle, and fed normal diet or pellets containing 0.11% UA in the initiation or promotion/progression phase. The formation of ACF in the colon and the activities of three types of mucosal SMase were examined. UA significantly reduced the incidence of ACF containing three or more crypts in the initiation group, but had no significant effect in the promotion/progression group. AOM reduced mucosal Alk-SMase activity, and the inhibitory effects could not be prevented by UA. However, in both AOM-treated and normal rats, UA increased the activity of colonic neutral SMase markedly and that of acid SMase activity mildly. These results indicate that UA has chemopreventive effects in the initiation phase of colon cancer associated with changes in SM metabolism.
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| 3. |
- Cheng, Yajun, et al.
(author)
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Curcumin decreases acid sphingomyelinase activity in colon cancer caco-2 cells
- 2007
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In: Planta Medica. - : Georg Thieme Verlag KG. - 0032-0943 .- 1439-0221. ; 73:8, s. 725-730
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Journal article (peer-reviewed)abstract
- Curcumin has been shown to inhibit cell growth and induce apoptosis in colon cancer cells. The metabolism of sphingomyelin has implications in the development of colon cancer. We examined whether curcumin affects the enzymes that hydrolyse sphingomyelin in Caco-2 cells. The cells were cultured in both monolayer and polarized conditions and stimulated with curcumin. The activities of sphingomyelinases were determined. Sphingomyelin and its hydrolytic products were analysed by thin layer chromatography. The changes of acid sphingomyelinase protein were examined by Western blotting. We found that curcumin reduced the hydrolytic capacity of the cells against choline-labelled sphingomyelin, associated with a mild increase of cellular sphingomyelin in the cells. Analysis of the hydrolytic products revealed that the activity was derived from acid sphingomyelinase not from phospholipase D. The curcumin-induced reduction of acid SMase required more than 8 h stimulation. Western blotting showed reduced acid sphingomyelinase protein after curcumin stimulation. The inhibitory effect was more potent in monolayer cells than in polarised cells. No changes of other sphingomyelinases were identified. In the concentrations inhibiting acid sphingomyelinase, curcumin inhibited DNA synthesis and induced cell death. In conclusion, curcumin inhibits acid sphingomyelinase and the effect might be involved in its anti proliferative property against colon cancer cells.
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| 4. |
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| 5. |
- Cheng, Yajun, et al.
(author)
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Ezetimibe Inhibits Expression of Acid Sphingomyelinase in Liver and Intestine.
- 2009
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In: Lipids. - : Wiley. - 0024-4201 .- 1558-9307. ; 44:10, s. 897-906
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Journal article (peer-reviewed)abstract
- Ezetimibe inhibits cholesterol absorption in the intestine. Sphingomyelin has strong interactions with cholesterol. We investigated the effects of ezetimibe on Sphingomyelinase (SMase) expression in intestine and liver. After feeding rats with ezetimibe (5 mg/kg per day) for 14 days, acid SMase activities in the liver and in the proximal part of small intestine were reduced by 34 and 25%, respectively. Alkaline SMase (alk-SMase) was increased in the proximal part of the small intestine. Administration of lower doses of ezetimibe reduced acid SMase only in the liver by 14% (P < 0.05). In cell culture studies, ezetimibe decreased acid SMase activity in Hep G2 and Caco-2 cells dose-dependently. The reductions were more rapid for Hep G2 cells than for Caco-2 cells. Western blot showed that acid SMase protein was decreased in both Hep G2 and Caco-2 cells by 100 muM ezetimibe. The SM content was increased in Hep G2 cells but not Caco-2 cells, and total cholesterol content was increased in both cell lines 24 h after stimulation with 100 muM ezetimibe. Mevastatin, the inhibitor of cholesterol synthesis, induced a mild increase in acid SMase activity in Hep G2 cells but not Caco-2 cells. Following the reduction of acid SMase, ezetimibe at high dose slightly increased alk-SMase activity. In conclusion, the study demonstrates an inhibitory effect of ezetimibe on acid SMase activity and expression in both liver and intestine.
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| 6. |
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| 7. |
- Cheng, Yajun, et al.
(author)
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Psyllium and fat in diets differentially affect the activities and expressions of colonic sphingomyelinases and caspase in mice.
- 2004
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In: British Journal of Nutrition. - 1475-2662. ; 91:5, s. 715-723
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Journal article (peer-reviewed)abstract
- Dietary fibre and fat affect colonic tumourigenesis and inflammation. Sphingomyelin metabolism may have implications for the pathogenesis of colonic tumours and ulcerative colitis. The present study examined the effects of psyllium and fat on the enzymes responsible for sphingomyelin metabolism and apoptosis in the colon. Mice were fed control, psyllium-containing (100 g/kg), high-fat (313 g/kg, 53 % energy as fat) or high-fat plus psyllium diets for 4 weeks. The activities of acid, neutral and alkaline sphingomyelinase (SMase), neutral ceramidase, and caspase 3, 8 and 9 in colonic mucosa were determined. The expressions of alkaline SMase and caspase 3 were examined. The psyllium-containing diet was found to increase significantly the activities of alkaline SMase and caspase 3 and decreased those of acid SMase and neutral ceramidase. The high-fat diet had opposite effects on these enzymes and attenuated the effects of psyllium. Western blotting showed that psyllium increased and high-fat decreased the levels of alkaline SMase and caspase 3 in colonic mucosa. The change in caspase 3 activity was positively correlated with that of alkaline SMase and negatively with acid SMase. No similar changes of acid and alkaline phosphatase activities in the colon or acid and neutral SMase activity in the liver were identified. In conclusion, colonic sphingomyelin metabolism and apoptosis were affected by psyllium and fat in an opposite manner. The results may have implications for colorectal tumourigenesis and inflammation.
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| 8. |
- Cheng, Yajun, et al.
(author)
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Purification, characterization, and expression of rat intestinal alkaline sphingomyelinase.
- 2002
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In: Journal of Lipid Research. - 1539-7262. ; 43:2, s. 316-324
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Journal article (peer-reviewed)abstract
- Intestinal alkaline sphingomyelinase (SMase) has physiological roles in the digestion of sphingomyelin (SM) and clinical implications in colonic carcinogenesis. In the present work, the enzyme from rat has been purified 1,589-fold with 11% recovery by elution of the intestine with bile salt, precipitation of the proteins by acetone, and several types of chromatographies. Its molecular mass was 58 kDa and optimal pH was 9 to 9.5. Under the optimal conditions, the V(max) was 930 micromol/h/mg and K(m) was about 1.25 mM. The enzyme could hydrolyze phosphatidylcholine at pH 7.4 in the presence of Ca2+; the rate was about 8% of that for SM. The activity against SM was dependent on bile salt. Taurine conjugated bile salts were much more effective than glycine conjugated ones, and the most effective bile salts were taurocholate and taurochenodeoxycholate. 3-[(3-Cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS) and Triton X100 (TX100) had no stimulatory effects. Unlike neutral SMase, intestinal alkaline SMase was not Mg2+ dependent, not inhibited by EDTA, and not inhibited by glutathione. The enzyme was stable during incubation with temperatures up to 50 degree C and in pHs from 7 to 10. Trypsin and chymotrypsin had no effects on its activity, and 10 mM dithiothreitol reduced its activity by 25%. A specific antibody against the enzyme was developed, and Western blot showed that the enzyme was expressed in the intestine but not in other organs. In conclusion, we purified a potentially important SMase in the intestine with several properties different from neutral SMase.
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| 9. |
- Duan, Jianxin, et al.
(author)
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Understanding the Molecular Activity of Alkaline Sphingomyelinase (NPP7) by Computer Modeling
- 2010
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In: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 49:42, s. 9096-9105
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Journal article (peer-reviewed)abstract
- The enzymes in the nucleotide pyrophosphatase/phosphodiesterase (NPP) family have various substrates such as nucleotides, phospholipids, and sphingolipids. The substrate specificity in relation to their structures is largely unknown because no mammalian NPP complex has been crystallized. NPP7, also called alkaline sphingomyelinase (alk-SMase), is a NPP family member that may have important implications in carcinogenesis and cholesterol absorption. The sequence of NPP7 is 36% similar to that of the closest NPP member, but NPP7 has no activity against nucleotides. In this work, we predict the three-dimensional structure of NPP7 by homology modeling using a recently crystallized NPP from bacteria. Using the model, we studied the substrate specificity of the enzyme by docking. The model generated explains the functional changes in previous mutagenesis studies and rationalizes the structural basis for the lack of activity toward nucleotides. An effort to shift the substrate specificity from sphingomyelin (SM) to nucleotide was not successful but revealed a site-directed mutation that increased activity toward SM. In conclusion, this is the first study to predict the structure of a mammalian NPP and its substrate specificity by molecular modeling. The information may be helpful in understanding the functional differences of NPP members.
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| 10. |
- Duan, Rui-Dong, et al.
(author)
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Changes of activity and isoforms of alkaline sphingomyelinase (nucleotide pyrophosphatase phosphodiesterase 7) in bile from patients undergoing endoscopic retrograde cholangiopancreatography.
- 2014
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In: BMC Gastroenterology. - 1471-230X. ; 14:1
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Journal article (peer-reviewed)abstract
- Alkaline sphingomyelinase (NPP7) is an ecto-enzyme expressed in intestinal mucosa, which hydrolyses sphingomyelin (SM) to ceramide and inactivates platelet activating factor. It is also expressed in human liver and released in the bile. The enzyme may have anti-tumour and anti-inflammatory effects in colon and its levels are decreased in patients with colon cancer and ulcerative colitis. Active NPP7 is translated from a transcript of 1.4 kb, whereas an inactive form from a 1.2 kb mRNA was found in colon and liver cancer cell lines. While the roles of NPP7 in colon cancer have been intensively studied, less is known about the function and implications of NPP7 in the bile. The present study examines the changes of NPP7 in bile of patients with various hepatobiliary diseases.
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