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PubMed2004

The influence of the region between residues 220 and 344 and beyond in Phrixotrix railroad worm luciferases green and red bioluminescence.

To find the regions having a major influence on the bioluminescence spectra of railroad worm luciferases, we constructed new chimeric luciferases switching the fragments from residues 1-219 and from 220-545 between Phrixotrix viviani (PxvGR; lambda(max) = 548 nm) green light-emitting luciferase and Phrixothrix hirtus (PxhRE; lambda(max) = 623 nm) red light-emitting luciferases. The emission spectrum (lambda(max) = 571 nm) and K(M) for luciferin in the chimera PxRE220GR (1-219, PxhRE; 220-545, PxvGR) suggested that the region above residue 220 of PxvGR had a major effect on the active site. However, switching the sequence between the residues 220-344 from PxvGR luciferase into PxhRE (PxREGRRE) luciferase resulted in red light emission (lambda(max) = 603 nm), indicating that the region 220-344 by itself does not determine the emission spectrum. Furthermore, the sequence before residue 220 of the green-emitting luciferase is incompatible for light emission with the sequence above residue 220 of PxhRE. These results suggest that the fragments before and after residue 220, which correspond to distinct subdomains, may fold differently in the green- and red-emitting luciferases, affecting the active site conformation.

Animals↗
PubMed2004

Early and late coronary deaths in the US Railroad study predicted by major coronary risk factors.

BACKGROUND: The purpose of this study was to explore the duration of the association of major coronary risk factors measured on a single occasion with coronary heart disease (CHD) deaths during 40 years in a population sample of middle-aged men. DESIGN: Measurement of age, systolic blood pressure, serum total cholesterol, and cigarette smoking was made on a single occasion in 2376 cardiovascular disease free men, aged 40-59, belonging to the US Railroad cohort of the Seven Countries Study enrolled in the late 1950s. During 40 years of follow up 627 men died from typical CHD (sudden death coronary death or definite myocardial infarction). METHODS: Eight partitioned proportional hazards models were solved, one for each independent 5-year block of follow up, to predict the risk of CHD death. Eight 5-year partitioned hazard scores, derived from the coefficients, were cumulated for each risk factor. RESULTS: The resulting curves showed a regularly increasing time trend in risk for coronary deaths as a function of serum cholesterol, systolic blood pressure and cigarette smoking, for the first 30-35 years of follow up followed by a loss of predictive power thereafter. The curves fit straight lines, with large squared correlation coefficients ranging from 0.96 to 0.99. There was a relatively constant strength in the association of risk factors levels with events, which are predicted irrespective of the distance from risk factor measurements. CONCLUSIONS: Measurement of major coronary risk factors taken on a single occasion in middle-aged men maintained a regular and almost monotonic relationship with the subsequent occurrence of CHD deaths for at least 30-35 years of follow up.

Age Factors↗
PubMed2006

AMP-activated protein kinase--the fat controller of the energy railroad.

AMP-activated protein kinase plays an important role in the regulation of lipid metabolism in response to metabolic stress and energy demand. It is also under endocrine control. AMPK acts at multiple steps and has a central role controlling fatty acid, triglyceride, and cholesterol synthesis, as well as the oxidation of fatty acids through direct phosphorylation effects and the control of gene transcription. As such, it can be considered to be the fat controller of the energy railroad. It is thought that AMPK may be a major mediator of the health benefits of exercise in mitigating the development of obesity and age-onset diseases.

AMP-Activated Protein Kinases↗
PubMed1989

Leisure time physical activity and coronary heart disease death. The US Railroad Study.

Seventeen to 20 years of mortality follow-up were used to study the relation of leisure time physical activity (LTPA) to coronary heart disease mortality and to all-cause mortality in white male US railroad workers (n = 3,043). This cohort was initially examined from 1957 to 1960, reexamined from 1962 to 1964, and followed until 1977 or death. LTPA was ascertained by a precursor of the Minnesota Leisure Time Physical Activity Questionnaire. The risk estimate for coronary heart disease death, after adjusting for age, was 1.39 for sedentary men who expended 40 kcal/wk in LTPA compared with very active men who expended 3,632 kcal/wk. This relation was attenuated by adjusting for other coronary heart disease risk factors, but it remained independent and significant. Caloric expenditure in light and moderate activity, as well as that performed in any intense activity, showed independent relations to cardiovascular death and all-cause mortality. Associations were slightly stronger in occupationally sedentary men. These results support the hypothesis that physical activity protects against death from coronary heart disease and all-cause mortality.

Coronary Disease↗
PubMed2004

Improved expression of novel red- and green-emitting luciferases of Phrixothrix railroad worms in mammalian cells.

Luciferases are widely used for the quantitative monitoring of gene expression in a variety of organisms. We successfully expressed novel red- and green-emitting luciferases of Phrixothrix railroad worms in mammalian cells in combination with the Kozak sequence and the CAG promoter. The characteristic properties of these luciferases indicate that they are appropriate reporter genes for the simultaneous monitoring of two gene expressions.

Animals↗
PubMed2000

Bioluminescence color determinants of Phrixothrix railroad-worm luciferases: chimeric luciferases, site-directed mutagenesis of Arg 215 and guanidine effect.

Chimeric proteins were produced using the green light-emitting luciferase of Phrixothrix vivianii (PxGr: lambda max = 548 nm) and the red light-emitting luciferase of Phrixothrix hirtus (PxRe: lambda max = 623 nm). Constructs containing residues 1-344 of the red light-emitting luciferase with residues 345-545 of the green light emitting one emitted red light (PxReGr; lambda max = 613 nm), while the reverse emitted green light (PxGrRe; lambda max = 552 nm). From these results we conclude that the region 1-344 determines the color of bioluminescence (BL) in railroad-worm luciferases, and that residues above 344 are not involved. The substitution R215S in the green light-emitting luciferase (PxGr) resulted in a approximately 40 nm redshift on the BL spectrum (lambda max = 585 nm) and an associated decrease of activity, whereas the same mutation in PxRe luciferase had little effect. Guanidine was shown to cause blueshifts in the BL spectra and stimulate the activity of the red-emitting luciferases (from lambda max = 623 to lambda max = 600 nm) and in PxGr R215S (from lambda max = 585 to lambda max = 560 nm) mutant luciferase, but not in the green-emitting luciferases, suggesting that guanidine can simulate positively charged residues involved in BL color determination.

Animals↗
PubMed1997

[Mental health and automation: remarks on a case study in the railroad industry]

This article focuses on some relations between mental health and current technical, organganizaizational, and contextual changes in work. The paper presents some features of a case study, examining the impacts of the work situation in a railroad company on traffic controllers and conductors of a computorized, automatedded system. The article also discusses the implications for the safety of the system as a whole, including passengers.

Journal Article↗