Aspergillus niger has been grown in glucose- and maltose-limited recycling cultures to determine the maximum growth yield, the maximum product yield for glucoamylase production, and the maintenance requirements at very slow specific growth rates. Using the linear equation for substrate utilization, and using the experimental data from both recycling experiments, both the maximum growth yield, Yxsm, and the maximum product yield, Ypsm, could be determined. The values estimated were 157 g biomass per mol maltose for Yxsm and 100 g protein per mol maltose for Ypsm. Expressed on a C1-basis these values are 0.52 and 0.36 C-mole per C-mol for respectively Yxsm and Ypsm. The found value for Ypsm is half the value found for alkaline serine protease production in Bacillus licheniformis, and it can be concluded that formation of extracellular protein is more energy consuming in filamentous fungi than in prokaryotic organisms. Maintenance requirements are no significant factor during growth of Aspergillus niger, and reported maintenance requirements are most probably due to differentiation.

Aspergillus niger↗

PubMedDate not supplied

Effect of acute zinc deficiency on insulin receptor binding in rat adipocytes.

Considerable data have been reported on the relationship between insulin resistance and zinc deficiency. In this study, insulin receptor binding was measured in isolated rat adipocytes. Two assays were carried out at 37 degrees C (binding and internalization) and 16 degrees C (binding) using 125I insulin 0.05-20 nM. A decreased insulin receptor binding was observed in zinc-deficient rat adipocytes, but we could not make any distinction between the specific zinc depletion effects and the effects of the caloric restriction induced by zinc deficiency.

Adipose Tissue↗

PubMedDate not supplied

Testing the cost-effectiveness of three alternative teams in implementing the Regional Center for Training (RCT) follow-up system in satellite centers.

Explore the source record for details and available documents.

Africa↗

PubMedDate not supplied

Hepatic fibrosis due to fascioliasis and/or schistosomiasis in Abis 1 village, Egypt.

An epidemiological study of fascioliasis and/or schistosomiasis was conducted in Abis 1 village. Stool specimens were collected from 2492 individuals and examined. Fascioliasis, alone or combined with schistosomiasis, was more prevalent among children aged between 5 years and 15 years than in adults. Serum procollagen III peptide (PIIIP) levels were determined as an indicator of active fibrosis, and liver histopathology and ultrasonography used as indicators of established fibrosis. PIIIP levels were significantly higher in children than in adults, and in mixed infections than in fascioliasis alone. In adults, fibrosis around granulomata detected by histopathology and grade 3 periportal fibrosis detected by sonography were encountered more frequently in dual than in single infections.

Adolescent↗

PubMedDate not supplied

Insulin sensitivity in zinc-depleted rats: assessment with the euglycaemic hyperinsulinic clamp technique.

The present knowledge about zinc deficiency and insulin-sensitivity is not yet established. Using three groups of rats fed zinc-depleted diet (ZD) zinc adequate diets, either Pair Fed or ad libitum for a six weeks period, we measured the glucose turn over by the euglycaemic hyperinsulinaemic clamp technique coupled with tritiated glucose as tracer. The basal hepatic glucose production (HGP) and insulinaemia were lower in zinc-depleted rats. At a low rate of insulin infusion (0.6 mU/min/rat) the zinc-depleted rats did not show any difference in hepatic insulin sensitivity compared with the pair-fed animals. At high level of insulin rate (3 mU/min/rat; 9 mU/min/rat), the zinc-depleted rats exhibited a lower glucose uptake compared to the two control groups (Pair-fed and Ad libitum animals). This peripheral insulin resistance is therefore related to a modification of insulin receptors, or post receptors events in zinc deficiency.

Animals↗

PubMedDate not supplied

Collagenase: an experimental study of intervertebral disc dissolution.

This study reports the use of a purified form of the enzyme collagenase (Nucleolysin) to effect dissolution of the normal nucleus pulposus in a series of dogs and monkeys. A consistent dissolution effect has been observed. The toxicity of the enzyme to surrounding local tissues has been studied in the same species with an indication of safety in all areas other than intrathecal administration. A margin of safety in intrathecal administration between the effective dose and toxic dose has been suggested in the monkey. Mice LD50 studies and systemic toxicity studies in dogs show a satisfactory margin of safety for this enzyme. Guinea pig studies show no significant antigenicity.

Adult↗