G Bomhoff | PubMed Health

PubMed1984

Bicycle ergometry and speed skating performance.

A comparison between maximal power output during cycling and skating was made, and correlates of skating performance with bicycle performance and skating technique were investigated. Twenty-five well-trained speed skaters performed two bicycle tests and a 500-m and 1500-m ice skating race. The power (P) during skating is calculated from ice and air friction losses: at 500 m P500 = 344 +/- 60 W and at 1500 m P1500 = 283 +/- 65 W. Stroke frequency and pre-extension knee angle as principle determining factors of P were determined. The two bicycle tests (of 30" and 2'30" duration, maximal performance) yield P30C = 875 +/- 86 W and P2.30C = 420 +/- 52 W with VO2max = 4.76 +/- 0.45 l/min. The highest correlate of P500 as well as of P1500 appeared to be P30C, respectively, r = 0.78 and r = 0.85. Correlation coefficients between the power during skating and P2.30C or VO2max have a value of about 0.6. If the stroke frequency and P30C are correlated with the power during skating, then high multiple correlation coefficients are obtained: at 500 m R = 0.85 and at 1500 m R = 0.90. The correlation of P30C suggests that the interindividual differences of skating performance at 500-m and 1500-m distances can be attributed substantially to differences in anaerobic power. Yet, the predictive value of the bicycle test for speed skating performance is low. The difference observed between maximal power output during cycling and skating is discussed.

Adipose Tissue↗

PubMed1976

Octopine and nopaline synthesis and breakdown genetically controlled by a plasmid of Agrobacterium tumefaciens.

Several nopaline degrading strains and one octopine degrading strain are shown to loose oncogenicity as well as the ability to utilize these guanidine compounds when they are cured of their TI plasmid. To investigate whether the specific genes involved in the utilization of one or the other compound are located on the plasmid, plasmid-transfer experiments have been performed. The plasmid from a nopaline degrading strain has been transferred to a naturally non oncogenic Agrobacterium namely A. radiobacter. Furthermore, the plasmid from an octopine degrading strain has been transferred to a plasmid-cured strain which originally had the capacity to utilize nopaline. Both kinds of experiments prove that the TI plasmid determines the strain specificity with regard to the utilization of either octopine or nopaline. They also demonstrate that the synthesis of either octopine or nopaline in crown gall cells is also determined by genes located on the TI plasmid harboured by the transforming A. tumefaciens strains.

Extrachromosomal Inheritance↗