Changes in the metabolism of intact animals caused by reduction or exclusion of carbohydrates from the diet have been the subject of active research (l-3). Changes occurring in the utilization of sugars by isolated tissues of animals fed with different amounts of carbohydrates have also been studied (3-6). The problem of interpreting these facts at the molecular level emerges as an important ch...

The severely diabetic subject has an excessive protein metabolism which returns to normal when sufficient carbohydrate utilization is reestablished. The current hypothesis to explain this is that restoration of the ability to oxidize carbohydrate spares protein, and the metabolism returns to normal. An alternative hypothesis, namely that insulin has a direct specific effect on protein metabolis...

TonB-dependent receptors (TBDRs) are outer membrane proteins mainly known for the active transport of iron siderophore complexes in Gram-negative bacteria. Analysis of the genome of the phytopathogenic bacterium Xanthomonas campestris pv. campestris (Xcc), predicts 72 TBDRs. Such an overrepresentation is common in Xanthomonas species but is limited to only a small number of bacteria. Here, we s...

• Early studies of the effects of epinephrine on the isolated and metabolically supported canine heart demonstrated increases in heart rate, contractile force, and myocardial oxygen consumption. The increases in myocardial oxygen consumption following epinephrine administration were roughly proportional to the increase in heart rate. In heart-lung preparations epinephrine administration resulte...

This study examined the ability of well-trained eumenorrheic women to increase muscle glycogen content and endurance performance in response to a high-carbohydrate diet (HCD; approximately 78% carbohydrate) compared with a moderate-carbohydrate diet (MD; approximately 48% carbohydrate) when tested during the luteal phase of the menstrual cycle. Six women cycled to exhaustion at approximately 80...

It is generally recognized that the pathways of fatty acid breakdown and of glucose catabolism (Embden-Meyerhof scheme) are confluent at the level of the 2-carbon fragment (acetyl-S-CoA). Nevertheless, several observations suggest an interplay between the metabolism of carbohydrate and that of fatty acids at a higher level: (a) Rats forcibly fed carbohydrate, as opposed to those fasted, exhibit...

ENDURANCE ATHLETES have a high capacity for the oxidation of fat during exercise as a legacy of their training. Therefore, it is intriguing that this capacity can be easily upregulated by the chronic consumption of a low-carbohydrate ( 2.5 g kg 1 day ), high-fat ( 65–70% of energy) diet. For example, 2–4 wk of exposure to such a diet in trained individuals has been shown to markedly increase fa...

Background Acetylated 4-O-(methyl)glucuronoxylan (GX) is the main hemicellulose in deciduous hardwood, and comprises a β-(1→4)-linked xylopyranosyl (Xylp) backbone substituted by both acetyl groups and α-(1→2)-linked 4-O-methylglucopyranosyluronic acid (MeGlcpA). Whereas enzymes that target singly acetylated Xylp or doubly 2,3-O-acetyl-Xylp have been well characterized, those targeting (2-O-MeG...

Ingestion of carbohydrate during exercise may blunt the stimulation of fat oxidative pathways by raising plasma insulin and glucose concentrations and lowering plasma free fatty acid (FFA) levels, thereby causing a marked shift in substrate oxidation. We investigated the effects of a single 2-h bout of moderate-intensity exercise on the expression of key genes involved in fat and carbohydrate m...