摘要:

Silyn‐Roberts (1988) reported that synchronization ofThalassomyxa australisby light‐dark‐cycles (LD) occurred whenDunaliellawas used as a food organism, whereas the use ofAmphiproraas a food organism lead to freerunning rhythmic changes between active and resting phases in this marine rhizopod.

ISSN:0022-1945    

DOI:10.1080/09291019109360104

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291019109360105

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The concentrations of non chloroplastic NAD+, NADP+, NADH and NADPH were followed during the development of the unicellular green alga Acetabularia. When Acetabularia enters the rapid growth phase, a slight increase in NAD+level is observed, and a slight decrease in both NADH and NADPH levels. In contrast, a huge decrease in both NAD+and NADP+concentrations take place at the time caps are initiated and develop, together with a slight increase in both reduced pyridine nucleotides concentrations. This increase has been confirmed and extended from the primordium stage to the cysts bearing caps: NADH and NADPH steadily increase in concentration.

ISSN:0022-1945    

DOI:10.1080/09291019109360106

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The purpose of this study was to examine whether the previously identified biweekly patterns of change in the growth rate of rainbow trout,Oncorhynchus mykiss,are associated with similar patterns of change in aspects of thyroid hormone and growth hormone physiology, and to continue to test the hypothesis that the lunar cycle may be serving as aZeitgeberfor the synchronization of this phenomenon.

ISSN:0022-1945    

DOI:10.1080/09291019109360107

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A group of hormones with potent diuretic/natriuretic activity, vasorelaxing properties and aldosterone secretion inhibiting action, are synthesized within the myocytes of cardiac atria and secreted by the stimulation of atrial stretch receptor. They are frequently elevated in hypertensives and may show a circadian rhythmicity in normal subjects. In the present study, to investigate the circadian pattern of ANF, we measured its plasma concentrations in a group of 12 healthy subjects and in a group of 10 patients with mild essential hypertension. None of the 10 hypertensives and of the 12 normotensives showed a significant circadian rhythm of ANF plasma concentrations. Also, we did not demonstrate a significant group rhythm for the two populations studied. Furthermore, no difference was seen in ANF plasma levels between mild hypertensives and healthy control subjects.

ISSN:0022-1945    

DOI:10.1080/09291019109360108

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The effect of DL‐p‐chlorophenylalanine (PCPA) and 5‐hydroxy‐L‐tryptophan (5‐HTP), which influence serotonin levels, were studied with respect to locomotion rates in earthworms,Lumbricus terrestris.The drugs were dissolved in .65% saline and injected into the coelom, and then the rate of locomotion was determined 6 hours later. PCPA, which inhibits serotonin synthesis, increased the rate of locomotion across a distance of 10 cm (19.07 ± 1.07 seconds) as compared to the rate of saline‐injected controls (28.56 ± .96 seconds). In general, saline‐injected earthworms crawled faster than 5‐HTP‐injected earthworms (Student'sttest P value less than .0005). Earthworms injected with saline at one of four times of the day crawled fastest at 2400 following injections at 1800 and the responses showed a circadian rhythm (ANOVA P value less than .005 and Cosinor P value less than .001). Earthworms injected 6 hours previously with 5‐HTP crawled slowest at 2400 as compared to the 2400 controls. Among the four times of day, 0600,1200,1800 or 2400 when the locomotion rate was determined, the responses to 5‐HTP showed a circadian rhythm (ANOVA P value less than .025 and Cosinor P value less than .017). These results should be taken into consideration when designing or interpreting experiments on neurotransmitters in earthworms and other annelids.

ISSN:0022-1945    

DOI:10.1080/09291019109360109

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Seasonal changes on intestinal ATPases activities of domesticated rainbow trout(Salmo gairdneri),reared under natural conditions, were studied during 1988.

ISSN:0022-1945    

DOI:10.1080/09291019109360110

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The D/L ratio, which expresses amount of activity during the dark part of the cycle over amount cf activity during the light part of this cycle can serve as a mesure of rhythm contrast: it indicates whether there is a sharp dichotomy between the activity phase and the resting phase. The drawback to this parameter is that it is highly responsive to phase. The solution is to define the active and resting phases in terms of a synchronizer type function which maximizes its intercorrelation with the target rhythm. This function can then be used to define the Active and Resting phases to compute a new, phase‐independant A/R index. Furtermore, the intercorrelation function value is also a measure the best fit of the rhythm to its synchronizer. An example of application of these methods is presented for inbred strains of mice C57BL/6 and BALB/c and their reciprocal Fls. Obtained heterosis effects indicate that the Fl rhythm fits the synchronizer better than the rhythm of the parental strains.

ISSN:0022-1945    

DOI:10.1080/09291019109360111

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Our major aims in this study were to determine the possible existence of ultradian rhythms related to migrating motor complex (MMC), as well as to characterize the existence of circadian rhythms in gallbladder bile concentration in fasting and feeding dogs. Conscious dogs with chronic indwelling gallbladder catheter to allow the periodic collection of bile by means of an automatized device, were used to determine if the composition of gallbladder bile shows rhythmic changes. During feeding, gallbladder bile concentration shows circadian rhythms peaking immediately before meal time in all biliary compounds. On the other hand, during interdigestive state an ultradian rhythm of periodic dilution (90 min period) of gallbladder bile during the bile concentrating process is observed.

ISSN:0022-1945    

DOI:10.1080/09291019109360112

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291019109360103

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor