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531.
532.
Ib Christian Klausen Lars Ulrik Gerdes Erik Berg Schmidt Jørn Dyerberg Ole Faergeman 《Human genetics》1992,89(4):384-388
Summary Previous studies in Greenland suggest that death rates from ischemic heart disease [IHD] are lower in Eskimos than in Danes and other Caucasian populations. This has been explained by a high intake of n-3 polyunsaturated fatty acids with beneficial effects on blood lipids and hemostasis. In other populations, lipoprotein(a) [Lp(a)] is associated with IHD, plasma concentrations of Lp(a) being genetically determined to a major extent. We have compared Lp(a) concentrations and apo(a) phenotypes in 120 Greenlandic Eskimos with those in 466 Danish men. The median Lp(a) concentration in Eskimos (8.7mg/dl;[95% CI 6.5–10.7]) was not significantly different from that in Danes (6.3mg/dl; [95% CI 5.2–7.0]), whereas the 90th percentile was significantly higher among Danes: 46.36mg/dl; [95% Cl 43.0–54.3] vs. 27.6mg/dl [95% CI 20.7–36.9]. In 20% of the Danes, but in only 8% of the Eskimos (P = 0.009), the concentration of Lp(a) exceeded 30mg/dl. The difference is probably explained by a low frequency of the low molecular weight apo(a) phenotypes among Eskimos, since the apo(a) isoforms F and B were absent, and the S1 and S2 types were present in only 3.3% of Eskimos. In contrast, these apo(a) isoforms were present in 26.6% of the Danes in either single-band or double-band phenotypes. The pattern of apo(a) polymorphism found in this study could provide part of a genetic explanation for the putative low rates of IHD in Eskimo populations. 相似文献
533.
534.
Marcia González-Teuber Alejandro Urzúa rea Morales Cristian Ibá?ez Luisa Bascu?án-Godoy 《Journal of Plant Ecology》2019,12(2):264
Aims
Desertification is a major concern in arid and semi-arid regions globally. Understanding interactions between vulnerable plant species and associated microbial symbionts may have important applications for conservation and restoration strategies in affected areas. 相似文献
535.
Mats Holmquist Ib Groth Clausen Shamkant Patkar Allan Svendsen Karl Hult 《Journal of Protein Chemistry》1995,14(4):217-224
To reveal the functional role of Glu87 and Trp89 in the lid ofHumicola lanuginosa lipase, site-directed mutagenesis at Glu87 and Trp89 was carried out. The catalytic performance of wild-type and mutated lipases was studied in transesterification reactions in cyclohexane at a controlled water activity. Two different acyl donors were used in the investigation: tributyrin, a natural substrate for a lipase, and vinyl butyrate, an activated ester suitable for fast and efficient lipase-catalyzed transformations in preparative organic synthesis. As acyl acceptor 1-heptanol was used. The Glu87Ala mutation decreased theV
max,app value with tributyrin and vinyl butyrate by a factor of 1.5 and 2, respectively. TheK
m,app for tributyrin was not affected by the Glu87Ala mutation, but theK
m,app for vinyl butyrate increased twofold compared to the wild-type lipase. Changing Trp89 into a Phe residue afforded an enzyme with a 2.7- and 2-fold decreasedV
max,app with the substrates tributyrin and vinyl butyrate, respectively, compared to the wild-type lipase. No significant effects on theK
m,app values for tributyrin or vinyl butyrate were seen as a result of the Trp89Phe mutation. However, the introduction of a Glu residue at position 89 in the lid increased theK
m,app for tributyrin and vinyl butyrate by a factor of >5 and 2, respectively. The Trp89Glu mutated lipase could not be saturated with tributyrin within the experimental conditions (0–680 mM) studied here. With vinyl butyrate as a substrate theV
max,app was only 6% of that obtained with wild-type enzyme. 相似文献