The influence of microflora and diet on gastro-intestinal parameters.
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Animals↗
Biomedical subjects
H de Boer
Publications and source records attributed to H de Boer.
[Intestinal flora of mice (author's transl)].
The literature on the build-up of the intestinal flora of mice in the course of time is reviewed. The intestine of the germ-free animal is colonized by large numbers of bacteria as rapidly as within a few days after birth. The ingestion of solid food and weaning are found to be times at which new species appear and others diminish. In addition, the relationship between microflora and host is discussed. Three types of relationship are described. The morphological forms present at various sites in the intestine are illustrated on the basis of personal scanning electron-microscopy. Finally, the effects of the presence of the intestinal flora on the host are briefly discussed.
Animals↗
In vivo transcription of rRNA operons in Escherichia coli initiates with purine nucleoside triphosphates at the first promoter and with CTP at the second promoter.
32P-labeled RNA was isolated from growing Escherichia coli and the 5' end nucleoside triphosphates of rRNA were analyzed after hybridization to various DNA fragments derived from one of the rRNA operons, rrnE. The results show that there are two transcription start sites for each rRNA operon in vivo, one initiating with ATP (or GTP), and the second initiating with CTP. Transcription from the first site was observed to be stronger than that from the second site. These two sites correspond to the two promoters identified in the previous in vitro studies, indicating that the two promoters are used in vivo. These results also demonstrate previously unrecognized transcription initiation with CTP in growing E. coli cells.
Cytidine Triphosphate↗
Power spectrum analysis of spontaneous fluctuations in the photoplethysmographic signal.
Direct measurement of variability in the peripheral circulation was performed by means of photoplethysmography, which provides assessment of blood volume in tissue and systolic blood volume increase. Both parameters showed oscillations at a relatively low frequency, about 0.02 Hz, and a relatively high frequency, about 0.3 Hz, which is related to respiration. These frequencies are similar to those found in measurements of heart rate variability--which is also obtained by measuring the photoplethysmographic period variability--but the powers of the different frequencies are different. The low frequency oscillation, which is attributed to the activity of the sympathetic nervous system, is more pronounced in the measurements of tissue blood volume and of systolic blood volume increase than in the measurement of heart rate.
Adult↗