排序方式: 共有110条查询结果,搜索用时 15 毫秒
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Rutanen J Pihlajamäki J Vänttinen M Salmenniemi U Ruotsalainen E Kuulasmaa T Kainulainen S Kuusisto J Laakso M 《Obesity (Silver Spring, Md.)》2007,15(12):2902-2907
Melanin concentrating hormone receptor-1 (MCHR1) is a centrally and peripherally expressed receptor that regulates energy expenditure and appetite. Single nucleotide polymorphisms (SNPs) of the MCHR1 gene have been previously associated with obesity, but the results are inconsistent among different populations. This study was performed to determine whether SNPs of MCHR1 affect glucose and energy metabolism. We screened six SNPs of MCHR1 in a cross-sectional study of 217 middle-age, non-diabetic Finnish subjects who were offspring of type 2 diabetic patients. Insulin secretion was evaluated by an intravenous glucose tolerance test and insulin sensitivity and energy metabolism by the hyperinsulinemic euglycemic clamp and indirect calorimetry. SNPs of MCHR1 were not associated with BMI, waist circumference, subcutaneous or intra-abdominal fat area, glucose tolerance, first-phase insulin release, insulin sensitivity, or energy metabolism. One SNP, which was in >0.50 linkage disequilibrium with the other five SNPs, was also screened in 1455 unrelated Finnish middle-age subjects in a population-based study. No differences in BMI, waist circumference, or glucose or insulin levels in an oral glucose tolerance test among the genotypes were found. In conclusion, SNPs of MCHR1 did not have effects on metabolic variables in humans. 相似文献
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Increased Production of Xylanase by Expression of a Truncated Version of the xyn11A Gene from Nonomuraea flexuosa in Trichoderma reesei
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Marja Paloheimo Arja Mntyl Jarno Kallio Terhi Puranen Pirkko Suominen 《Applied microbiology》2007,73(10):3215-3224
We have previously shown that the Nonomuraea flexuosa Xyn11A polypeptides devoid of the carbohydrate binding module (CBM) have better thermostability than the full-length xylanase and are effective in bleaching of pulp. To produce an enzyme preparation useful for industrial applications requiring high temperature, the region encoding the CBM was deleted from the N. flexuosa xyn11A gene and the truncated gene was expressed in Trichoderma reesei. The xylanase sequence was fused to the T. reesei mannanase I (Man5A) signal sequence or 3′ to a T. reesei carrier polypeptide, either the Man5A core/hinge or the cellulose binding domain (CBD) of cellobiohydrolase II (Cel6A, CBHII). The gene and fusion genes were expressed using the cellobiohydrolase 1 (cel7A, cbh1) promoter. Single-copy isogenic transformants in which the expression cassette replaced the cel7A gene were cultivated and analyzed. The transformants expressing the truncated N. flexuosa xyn11A produced clearly increased amounts of both the xylanase/fusion mRNA and xylanase activity compared to the corresponding strains expressing the full-length N. flexuosa xyn11A. The transformant expressing the cel6A CBD-truncated N. flexuosa xyn11A produced about 1.9 g liter−1 of the xylanase in laboratory-scale fermentations. The xylanase constituted about 25% of the secreted proteins. The production of the truncated xylanase did not induce the unfolded protein response (UPR) pathway. However, the UPR was induced when the full-length N. flexuosa xyn11A with an exact fusion to the cel7A terminator was expressed. We suggest that the T. reesei folding/secretion machinery is not able to cope properly with the bacterial CBM when the mRNA of the full-length N. flexuosa xyn11A is efficiently translated. 相似文献
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Purification and characterization of leucine aminopeptidase from kidney bean cotyledons 总被引:1,自引:0,他引:1
Anita Mikkonen 《Physiologia plantarum》1992,84(3):393-398
A leucine aminopeptidase (EC 3,4,11.1) was purified from cotyledons of resting kidney beans ( Phaseolus vulgaris L. cv. Processor) by acidic extraction, ammonium sulfate fractionation and chromatography on DEAE-Sephacel, Sephacryl S-300, Mono Q HPLC and Superose HPLC columns. The yield of the 317-fold purified enzyme was 9%. On gel filtrations on Sephacryl S-300 and Superose HPLC the elution volumes of the enzyme corresponded to an M, of 360 000. The enzyme gave one band on native gel electrophoresis and an electrophoretic titration in an immobilized pH gradient gave a single curve with a pI of 4.8. Two bands were observed in an SDS-gel electrophoresis with Mr values of 58 000 and 60 000 both with and without reduction by 2-mercaptoethanol, indicating that subunits of the enzyme are not linked by disulphide bridges. The purified enzyme most rapidly liberated Leu and Ala of the N-termini of di-and oligopeptides, optimally at pH 9.0 ± 0.5. The enzyme was stable in the presence of glycerol, dithiothreitol and Mg2+ , while the latter also had an activating effect. Bestatin inhibited the enzyme competitively with Leu-Gly-Gly with a Ki -value of 1.5 nM . These observations indicate that the purified aminopeptidase from the cotyledons of resting kidney beans corresponds to the cytosolic leucine aminopeptidase of mammalian tissues (EC 3.4, 11.1). The high enzyme activity observed suggests that this aminopeptidase has an important role in the production of free amino acids during germination. 相似文献
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Salla Marttila Ilkka Porali T.-H. David Ho Anita Mikkonen 《Cell biology international》1993,17(2):205-212
The expression of a 30 kD cysteine endoprotease (EP-B) was studied by in situ hybridization and immunomicroscopy to clarify its role in germinating barley grains. At the beginning of germination, EP-B mRNA was expressed in the scutellar epithelium and aleurone cells next to the embryo. Later, mRNA levels were highest in the aleurone layer proceeding to the distal end of the grain. During the first day of germination, EP-B protein was strongly localized to the germ aleurone and scutellar epithelium from where the secretion into the starchy endosperm began. Secretion was also observed to proceed along the aleurone layer to the distal end. These results show that EP-B is differentially localized during germination, and both scutellum and aleurone layer are able to synthesize and secrete EP-B protein. 相似文献
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Jarno Rutanen Jussi Pihlajamki Pauli Karhap Ilkka Vauhkonen Johanna Kuusisto Leena Moilanen Mykknen Markku Laakso 《Obesity (Silver Spring, Md.)》2004,12(7):1060-1066
Objective: The melanocortin‐4 receptor (MC4R) regulates energy intake. On the basis of animal studies, it may also regulate energy expenditure. Research Methods and Procedures: The effect of the Val103Ile polymorphism of the MC4R gene on energy metabolism was studied in 229 middle‐aged nondiabetic subjects (Group 1, age 51.2 ± 9.8 years, BMI 26.8 ± 4.5 kg/m2) and on weight gain in 1013 elderly subjects (Group 2, age 69.9 ± 2.9 years, BMI 27.4 ± 4.1 kg/m2) during a 3.5‐year follow‐up study. In Group 1, insulin sensitivity, energy expenditure, and substrate oxidation were measured with the hyperinsulinemic euglycemic clamp combined with indirect calorimetry. Results: In Group 1, the Val103Ile genotype was associated with high rates of energy expenditure (63.42 ± 13.40 in eight subjects with the Val103Ile genotype vs. 59.86 ± 7.33 J/kg per minute in 221 subjects with the Val103Val genotype, p = 0.007), high rates of glucose oxidation (8.90 ± 6.15 vs. 6.07 ± 4.38 μmol/kg per minute, p = 0.020), and low levels of free fatty acids (0.45 ± 0.18 vs. 0.56 ± 0.23 mM, p = 0.029) in the fasting state, and with high rates of glucose oxidation during the clamp (18.88 ± 4.63 vs. 17.60 ± 3.24 μmol/kg per minute, p = 0.031). In Group 2, the 103Ile allele was associated with an increase in weight gain during the follow‐up (0.78 ± 3.98 vs. ?0.82 ± 3.98 kg, p = 0.038). Discussion: The Val103Ile polymorphism of the MC4R gene is associated with energy expenditure in humans. Furthermore, it may associate with glucose oxidation, free fatty acid levels, and weight gain. 相似文献
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Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) differ in their suitability as hosts for the endangered freshwater pearl mussel (Margaritifera margaritifera) in northern Fennoscandian rivers
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Jouni K. Salonen Pirkko‐Liisa Luhta Eero Moilanen Panu Oulasvirta Jarno Turunen Jouni Taskinen 《Freshwater Biology》2017,62(8):1346-1358
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Littoral species diversity and biomass: concordance among organismal groups
and the effects of environmental variables 总被引:1,自引:0,他引:1
Kimmo T.?TolonenEmail author Ismo J.?Holopainen Heikki?H?m?l?inen Minna?Rahkola-Sorsa Pasi?Yl?stalo Krista?Mikkonen Juha?Karjalainen 《Biodiversity and Conservation》2005,14(4):961-980
Biomass and species diversity (richness and evenness) of littoral organisms were explored in 27 sites in three basins of the large Lake Saimaa system in eastern Finland. The basins differed in degree of nutrient loading and trophic status. Six organismal groups, i.e., phytoplankton, periphyton, macrophytes, crustacean zooplankton, benthic macroinvertebrates and fish were studied. Factors affecting the biomass and diversity of these groups were explored by multiple stepwise regression analysis. The biomass of different groups was explained by the same variables, mainly nutrients, while diversity was associated with different environmental factors among the studied groups. The biomass of periphyton, phytoplankton, zooplankton, and fish correlated significantly with each other. There was also an apparent association between the biomass of macrophytes and that of benthic invertebrates. However, no significant correlations were found among the diversity of the studied groups. In accordance with previous studies, our results did not support the existence of species-rich hotspots or the possibility of using any surrogate taxon to reveal overall biodiversity. Thus, for conservation planning, biological surveys should include extensive collection of taxonomic groups and organisms at all trophic levels. 相似文献
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