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Alterations in nucleotide content of human lung fibroblasts infected with Mycoplasma pneumoniae
Abstract:
The nucleotide content of normal MRC-5 human lung fibroblasts and fibroblasts infected with Mycoplasma pneumoniae PI 1428 was determined. Nucleotides from control and infected fibroblasts were extracted with 5% trichloracetic acid. After neutralization of the extracts, the nucleotides in the extracts were separated by anion-exchange chromatography. Significant differences were found between the nucleotide content of the control and infected cells. Nucleotide triphosphate levels were twofold higher in the control fibroblasts than in the infected fibroblasts 4 h after the initiation of infection. At the same time, nucleotide diphosphate and monophosphate levels were higher in the infected fibroblasts than in the control fibroblasts. Determination of the energy charge ratio for each set of nucleotides (adenosine, guanosine, cytidine, and uridine) demonstrated a shift of nucleotide content in the infected fibroblasts. Immediately after infection, the energy charge for each set of nucleotides was higher for the control fibroblasts than it was for the infected fibroblasts. This pattern continued throughout the infection period with only minor exceptions. The work presented here indicates a loss of energy charge in fibroblasts infected with M. pneumoniae and may help to explain some of the metabolic changes and cell damage which accompany infection.
Insights
Mycoplasma pneumoniae infection alters nucleotide levels in human lung fibroblasts, leading to a significant loss of cellular energy charge. This finding helps explain metabolic changes and cell damage during infection.
Area of Science:
- Cell Biology
- Microbiology
- Biochemistry
Background:
- Mycoplasma pneumoniae is a pathogen that infects human respiratory tracts.
- Fibroblasts are crucial cells in lung tissue and play a role in host defense.
- Understanding host-pathogen interactions at the cellular level is vital for explaining disease pathogenesis.
Purpose of the Study:
- To investigate the impact of Mycoplasma pneumoniae infection on nucleotide content and energy charge in MRC-5 human lung fibroblasts.
- To determine how nucleotide profiles change during the course of M. pneumoniae infection.
- To correlate observed nucleotide changes with potential mechanisms of cell damage.
Main Methods:
- Extraction of nucleotides from control and M. pneumoniae-infected MRC-5 fibroblasts using trichloroacetic acid.
- Separation and quantification of nucleotides via anion-exchange chromatography.
- Calculation of the energy charge ratio for key nucleotide sets (adenosine, guanosine, cytidine, uridine).
Main Results:
- Infected fibroblasts showed significantly lower levels of nucleotide triphosphates compared to control cells at 4 hours post-infection.
- Conversely, nucleotide diphosphate and monophosphate levels were elevated in infected fibroblasts.
- A consistent decrease in the energy charge ratio was observed in infected fibroblasts throughout the infection period.
Conclusions:
- Mycoplasma pneumoniae infection induces a notable loss of cellular energy charge in human lung fibroblasts.
- The observed shifts in nucleotide metabolism likely contribute to the metabolic dysfunction and cellular damage associated with M. pneumoniae infections.
- This study provides insights into the biochemical mechanisms underlying M. pneumoniae pathogenesis.