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Published on: February 27, 2011
[Metabolism of C(14)-glucose by Ascaridia galli]
Han Jong Rim1, Kwang Soo Kim, Soo Hyun Seong
1Department of Parasitology and Institute of Endemic Diseasess, Korea.
Abstract:
The fowl nematode Ascaridia galli employed in this experiment was obtained from the intestine of domestic fowls at the local market. The worms selected and washed several times in normal sterilized saline solution. Each about thirty of intact worms were incubated in 50 cc volume of special incubation flasks with incubation mixture consisting of 10 cc of Krebs-Ringer phosphate buffer (pH 7.4) to which were added universally labeled C14-glucose and non-radioactive carrier glucose so as to contain concentration of 200 mg per cent. The worms were allowed to incubation for 3 hours in Dubnoff metabolic shaking incubator at 38 degrees C. After incubation period, respiratory CO2 samples from central well of incubation flask were analysed for total CO2 production rate and their specific activity of respiratory CO2. Glycogen samples isolated from worms were analysed for uptake rate was determined by analyzing the difference of the glucose concentration in a medium before and after incubation period. Radioactivities of these series of experiments were counted by an endwindow Geiger-Muller counter as an infinitely thin samples. The quantitative analysis of C(14)-glucose utilized by Ascaridia galli was summarized as the following. 1. The glucose uptake rate by A. galli was a mean value of 1.73 +/- 0.32 micro M/hr/g of wet wt. and total CO2 production rate by the worms averaged 8.44 +/- 1.11 micro M/hr/g of wet wt. The relative specific activity of respiratory CO2 (R.S.A CO2) averaged 2.68 +/- 0.38 per cent. Thus, a man of 2.68 per cent of total CO2 production rate was originated from the glucose in the medium, therefore the rate of CO2 production derived from medium glucose was a mean of 0.23 +/- 0.03 micro M/hr/g of wet wt. Thus, the average value of 2.58 +/- 0.55 percent (R.G.D CO2)of glucose utilized by the worms from the medium glucose was oxidized to respiratory CO2. 2. The tissue concentration of glycogen in A. galli was a mean of 22.59 +/- 1.18 mg per gram of wet wt or 2.26 +/- 0.123 percent per gram, and the turnover rate of glycogen pool yielded with a mean of 0.17 +/- 0.04 percent per hour or 0.037 +/- 0.006 miligram per hour per gram of wet wt. Therefore, a mean value of 16.37 +/- 4.04 per cent (R.G.D gly) of glucose was incorporated to the glycogen. 3. These data account for that at least 18.95 per cent of the utilized glucose by the worms participated in furnishing the oxidation into respiratory CO2 and the synthetic process into glycogen. According to the above data of the experiment, it is suggested in the metabolic process of glucose by Ascaridia galli that the synthetic process into the glycogen is more active than the oxidative process into the respiratory CO2.
Insights
This study reveals that the fowl nematode Ascaridia galli prioritizes glycogen synthesis over CO2 production when metabolizing glucose. This finding offers insights into parasitic worm glucose utilization and metabolism.
Area of Science:
- Parasitology
- Biochemistry
- Molecular Metabolism
Background:
- Ascaridia galli is a common fowl nematode impacting poultry health.
- Understanding parasitic worm metabolism is crucial for developing targeted interventions.
- Glucose metabolism pathways in A. galli have not been fully elucidated.
Purpose of the Study:
- To quantitatively analyze glucose utilization by Ascaridia galli.
- To determine the metabolic fate of glucose, specifically oxidation to CO2 and incorporation into glycogen.
- To compare the rates of glucose oxidation versus glycogen synthesis in A. galli.
Main Methods:
- Intact Ascaridia galli worms were incubated with C14-labeled glucose in Krebs-Ringer phosphate buffer.
- Respiratory CO2 production and its specific activity were measured using a Geiger-Muller counter.
- Glycogen concentration and turnover rates were determined in worm tissue samples.
Main Results:
- A. galli exhibited a glucose uptake rate of 1.73 ± 0.32 μM/hr/g wet wt.
- Total CO2 production averaged 8.44 ± 1.11 μM/hr/g wet wt., with 2.68 ± 0.38% originating from glucose.
- Approximately 16.37 ± 4.04% of utilized glucose was incorporated into glycogen.
Conclusions:
- At least 18.95% of utilized glucose contributes to either CO2 production or glycogen synthesis.
- The synthetic process of incorporating glucose into glycogen is more active than its oxidative process into respiratory CO2 in A. galli.
- Findings suggest a metabolic preference for glycogen storage over immediate energy production via oxidation in this nematode.
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