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A C Beynen

Publications and source records attributed to A C Beynen.

4 recordsLinked to original sources
PubMed1992

Influence of a natural-ingredient diet containing Phaseolus vulgaris on the colonization by segmented, filamentous bacteria of the small bowel of mice.

The appearance of segmented, filamentous bacteria (SFBs) in the small bowel of mice is influenced by the composition of the diet, but the dietary components responsible are not known. The addition of ground, whole Phaseolus vulgaris to a natural-ingredient diet at the expense of part of the skim milk powder, ground barley and wheat middlings components, caused an increase of the colonization of the mouse small bowel by SFBs. This effect was not seen when whole Phaseolus was added to a purified diet at the expense of part of the casein, corn oil, coconut fat, corn starch, dextrose and cellulose components. In an attempt to identify the fraction of Phaseolus that might contain SFB-inducing substances, the skin and kernel fraction of the bean were added to the natural-ingredient diet. The skin and kernel fraction were found to be as effective in inducing SFB appearance as was whole Phaseolus.

Animal Feed↗
PubMed1992

Different degree of ileal colonization by segmented, filamentous bacteria in two strains of mice.

Segmented, filamentous bacteria (SFBs) are autochthonous, apathogenic inhabitants of the ileum of various animal species. Outbred Swiss (Cpb:SE) mice have significantly higher degrees of SFB colonization than do inbred BALB/c mice. The present studies were carried out to identify determinants of this strain difference. In a cross-fostering experiment it was shown that SFB colonization of the pups is determined by the strain of the pups themselves rather than by the strain of the nursing dam. Thus, maternal effects may not be involved in SFB colonization. In a cross-infecting experiment using germ-free and SFB-positive animals of the two mouse strains, it was found that ileal SFB colonization is determined by host characteristics rather than by origin of the SFBs. Thus, SFBs that are specific for a given mouse strain may not exist in the two strains of mice. It is concluded that the mouse strain difference in SFB colonization is determined by host characteristics, which probably have a genetic basis.

Animals↗
PubMed1979

Opposite effects of insulin and glucagon in acute hormonal control of hepatic lipogenesis.

Conditions for the isolation of rat hepatocytes that are responsive to insulin with regard to fatty acid synthesis were explored. Cells prepared according to the procedure of Ingebretsen and Wagle require the presence of fetal calf serum for insulin expression. Cells isolated by the Seglen method are the preparation of choice, since they respond to insulin in a simple, well-defined medium and, moreover, show much higher basal rates of fatty acid synthesis. In the latter cells isolated from fed male rats, the rate of fatty acid synthesis, as determined by tritium incorporation from [3H]H2O at 37 degrees C, is enhanced within 30 min after addition of insulin to the incubation medium; with glucagon, it is depressed. In the presence of insulin, the cellular content of malonyl coenzyme A is noticeably increased, whereas the concentrations of pyruvate, lactate, and citrate are not markedly affected. Glucagon, on the other hand, decreases the concentrations of all four intermediates. The activity of acetyl-CoA carboxylase is stimulated and depressed after addition of insulin and glucagon, respectively. In all conditions tested, the activity of acetyl-CoA carboxylase correlates with the rate of fatty acid synthesis, which in turn correlates with the cellular level of malonyl-CoA.

Animals↗