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- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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- Davis, Nichola J., et al.
(författare)
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Predictors of Sustained Reduction in Energy and Fat Intake in the Diabetes Prevention Program Outcomes Study Intensive Lifestyle Intervention
- 2013
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Ingår i: Journal of the American Dietetic Association. - : Elsevier BV. - 0002-8223. ; 113:11, s. 1455-1464
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Tidskriftsartikel (refereegranskat)abstract
- Background Few lifestyle intervention studies examine long-term sustainability of dietary changes. Objective To describe sustainability of dietary changes over 9 years in the Diabetes Prevention Program and its outcomes study, the Diabetes Prevention Program Outcomes Study, among participants receiving the intensive lifestyle intervention. Design One thousand seventy-nine participants were enrolled in the intensive lifeStyle intervention arm of the Diabetes Prevention Program; 910 continued participation in the Diabetes Prevention Program Outcomes Study. Fat and energy intake derived from food frequency questionnaires at baseline and post-randomization Years 1 and 9 were examined. Parsimonious models determined whether baseline characteristics and intensive lifestyle intervention session participation predicted sustainability. Results Self-reported energy intake was reduced from a median of 1,876 kcal/day (interquartile range [IQR]=1,452 to 2,549 kcal/day) at baseline to 1,520 kcal/day (IQR=1,192 to 1,986 kcal/day) at Year 1, and 1,560 kcal/day (IQR=1,223 to 2,026 kcal/ day) at Year 9. Dietary fat was reduced from a median of 70.4 g (IQR=49.3 to 102.5 g) to 45 g (IQR=32.2 to 63.8 g) at Year 1 and increased to 61.0 g (IQR=44.6 to 82.7 g) at Year 9. Percent energy from fat was reduced from a median of 34.4% (IQR=29.6% to 38.5%) to 27.1% (IQR=23.1% to 31.5%) at Year 1 but increased to 35.3% (IQR=29.7% to 40.2%) at Year 9. Lower baseline energy intake and Year 1 dietary reduction predicted lower energy and fat gram intake at Year 9. Higher leisure physical activity predicted lower fat gram intake but not energy intake. Conclusions Intensive lifestyle intervention can result in reductions in total energy intake for up to 9 years. Initial success in achieving reductions in fat and energy intake and success in attaining activity goals appear to predict long-term success at maintaining changes.
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- Billings, Liana K., et al.
(författare)
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The Influence of Rare Genetic Variation in SLC30A8 on Diabetes Incidence and beta-Cell Function
- 2014
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 99:5, s. 926-930
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Tidskriftsartikel (refereegranskat)abstract
- Context/Objective: The variant rs13266634 in SLC30A8, encoding a beta-cell-specific zinc transporter, is associated with type 2 diabetes. We aimed to identify other variants in SLC30A8 that increase diabetes risk and impair beta-cell function, and test whether zinc intake modifies this risk. Design/Outcome: We sequenced exons in SLC30A8 in 380 Diabetes Prevention Program (DPP) participants and identified 44 novel variants, which were genotyped in 3445 DPP participants and tested for association with diabetes incidence and measures of insulin secretion and processing. We examined individual common variants and used gene burden tests to test 39 rare variants in aggregate. Results: We detected a near-nominal association between a rare-variant genotype risk score and diabetes risk. Five common variants were associated with the oral disposition index. Various methods aggregating rare variants demonstrated associations with changes in oral disposition index and insulinogenic index during year 1 of follow-up. We did not find a clear interaction of zinc intake with genotype on diabetes incidence. Conclusions: Individual common and an aggregate of rare genetic variation in SLC30A8 are associated with measures of beta-cell function in the DPP. Exploring rare variation may complement ongoing efforts to uncover the genetic influences that underlie complex diseases.
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