摘要:

A comparative analysis is presented which validates the practice of measuring free‐running period (r) of circadian locomotor activity by means of the slope of a line eye‐fitted to daily onset of activity. The slope of a linear regression calculated through daily onset of activity gives virtually the same ras the slope of the eye‐fitted line. The center‐of‐gravity (COG) of locomotor activity (defined as the mean daily clock time of all recorded activity impulses) is uniquely defined and free of subjective evaluation. COG is shown to be a meaningful representation of the central tendency of circadian activity; calculation of a regression through daily COG of activity also provides an accurate measurement of #GT.

ISSN:0022-1945    

DOI:10.1080/09291018009359682

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

3H‐leucine incorporation was measured in a cell‐free system from rat liver. Even under conditions of constant amino acid concentrations and energy supply, we observed a diurnal rhythmicity when analysing tissue samples from serially sacrificied animals. Maximum incorporation rates were found during dark‐time, whereas a characteristic minimum occurred in the second half of light‐time. Injections of glucagon 20 min prior to killing significantly increased the incorporation rates. The degree of stimulation depended on the phase of the diurnal cycle; the periodicity of stimulation by glucagon approximately paralleled the rhythm of unstimulated incorporation. Despite of the stimulatory effect of glucagon administrationinvivo,addition of cAMP (and also cGMP) to thein vitrosystem resulted in an inhibition, which represents, however, a well‐known unphysiologic phenomenon. Nevertheless, the extent of inhibition also varied within the diurnal cycle; these changes were due to differing temporal inhibition kinetics.

ISSN:0022-1945    

DOI:10.1080/09291018009359683

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

5‐Aminolevulinate synthetase activity was measured in livers of adult male rats by means of an improved assay. The enzyme exhibited a diurnal rhythm with a maximum during dark‐time. Inductions by allylisopropylacetamide during diurnal increase and decrease of enzyme activity resulted in the same amount of additionally formed enzyme.

ISSN:0022-1945    

DOI:10.1080/09291018009359684

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

In rat prostate, the activity of tyrosine aminotransferase showed a diurnal rhythm with a maximum during dark‐time. No clear‐cut rhythmicity was observed, however, in acid phosphatase activity of this organ.

ISSN:0022-1945    

DOI:10.1080/09291018009359685

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

In 372 full grown non‐gravid female guinea pigs, the average number of Kurloff cells in blood was 402/mm3, s.d.: 366.5. The distribution was positively skewed. This distribution is subject to seasonal variations since the figures are significantly higher from the beginning of May to the end of October than from the beginning of November to the end of April.

ISSN:0022-1945    

DOI:10.1080/09291018009359686

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The circadian caecotrophy rhythm of the rabbit was monitored in LD 12:12 and continuous light of two different intensities.1.The length of the free‐running rhythm and the phaseangleof theen trained rhythm were found to be influenced by after‐effects for a considerable time span of up to 75 days.2.The free running period in LL of 1200lux was significantly longer (24.94 ± 0.71(SD)h) than in 10 lux (24.23 ± 0.39 (SD) h).3.In 10 lux the caecotrophy rhythm ran free monophasically, even in those rabbits practising caecotrophy twice in LD 12:12. This confirms initial observations made in 300 lux. In LL of 12001ux, “splitting"ocurredin 4 out of 8 animals.4.The entrainment following re‐insertion of the LD 12:12 after LL depended on the strength of the Zeitgeber and the phase of the rhythm at the end of LL.5.A correlation existed between the phase angle difference and the length of the spontaneous period: the shorter the spontaneous period, the less negative was the p.a.d.6.The results suggest that the caecotrophy rhythm of the rabbit accords in several chronobiological characteristics to the activity rhythm of nocturnal rodents.

ISSN:0022-1945    

DOI:10.1080/09291018009359687

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Human erythrocytes were isolated and incubated in various media at constant and light‐dark‐conditions. Within these suspension cultures the activities of the tightly membrane‐bound enzyme acetylcholinesterase and of the partly bound enzyme pyruvate kinase, were measured during 24 hours. Membrane dynamic structure was investigated during the same time interval by means of the valinomycin‐facilitated potassium transport, whereas membrane fluidity was determined using the fluorescence depolarization method. In all cases considerable changes during the incubation time were registered, some of which showed a 9 h‐, 12 h‐, or 24 h‐periodicity. However, it was not possible to arrive at statistically significant periodicities after averaging the individual experiments, except that in some single experiments the acetylcholinesterase activity seemed to be rhythmic. This result may be due in part to the different phasing of individual red blood cell suspensions.

ISSN:0022-1945    

DOI:10.1080/09291018009359688

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

A statistical method or analysing the rhythmicity of several short, non‐synchronous time series in biological systems is discussed. As a first step the single series are analysed by techniques based on linear regression and variance methods. As a second step, some test statistics are proposed for combining the results of the single curves. The statistical procedure is demonstrated by two examples: fluorescence intensity of dye‐labelledDrosophilasalivary gland cells in vitro and acetylcholinesterase activity in human erythrocyte suspensions.

ISSN:0022-1945    

DOI:10.1080/09291018009359689

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291018009359681

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor