Related Experiment Video
Updated: Jun 19, 2026
Following in Real Time the Impact of Pneumococcal Virulence Factors in an Acute Mouse Pneumonia Model Using Bioluminescent Bacteria
Published on: February 23, 2014
THE CORRELATION OF CERTAIN PHENOMENA OCCURRING DURING THE GROWTH OF PNEUMOCOCCUS
1Hospital of The Rockefeller Institute for Medical Research.
Abstract:
The growth of a culture of pneumococcus was followed together with the time relations of some of the phenomena incident thereto. There were, roughly speaking, three periods of growth: first, the period of maximum rate, or logarithmic period; second, a brief stationary period; and third, the period of decline, during which actual death of individual organisms in the culture occurred. It has been pointed out that the usual preliminary latent period was avoided by the use of relatively large inoculum, obtained from a culture which was itself in the logarithmic period of growth. During the height of growth activity of the culture certain changes in the substrate became demonstrable. Between the 7th and 10th hours the reaction of the medium was changed by the production of acid and the soluble specific substance was detected. At a somewhat later time in the logarithmic period of the culture peroxide was demonstrable and, simultaneously with the appearance of this substance, the substrate acquired the ability to change catalase-free crystalline hemoglobin to methemoglobin. Moreover, changes then occurred in the cultural fluid, such that, after the removal of the parent organisms by filtration, it no longer supported growth when seeded with either the pneumococcus or staphylococcus. These changes occurred early in the logarithmic period of growth of the culture.
Insights
This study details pneumococcus (Streptococcus pneumoniae) growth phases and associated biochemical changes. Key findings include acid and peroxide production, hemoglobin modification, and growth inhibition by the culture medium during the logarithmic growth phase.
Area of Science:
- Microbiology
- Bacteriology
- Biochemistry
Background:
- Understanding bacterial growth dynamics is crucial for microbiology.
- Pneumococcus (Streptococcus pneumoniae) is a significant human pathogen.
- Characterizing growth-phase-dependent phenomena aids in developing targeted interventions.
Purpose of the Study:
- To investigate the temporal relationship between pneumococcus growth phases and associated biochemical alterations.
- To identify key metabolic byproducts and their effects during active bacterial proliferation.
- To understand how the culture medium changes during pneumococcus growth.
Main Methods:
- Culturing pneumococcus with a large inoculum to bypass the lag phase.
- Monitoring bacterial growth and identifying distinct growth periods (logarithmic, stationary, decline).
- Analyzing culture supernatant for acid production, soluble specific substance, peroxide, and methemoglobin formation.
Main Results:
- Pneumococcus growth exhibited three phases: logarithmic, stationary, and decline.
- Acid production and soluble specific substance were detected between 7-10 hours.
- Peroxide appeared later in the logarithmic phase, leading to hemoglobin modification and inhibiting subsequent bacterial growth.
Conclusions:
- Bacterial growth phases correlate with specific metabolic activities and substrate changes.
- Early logarithmic phase alterations in the culture medium can inhibit further growth.
- These findings provide insights into pneumococcus physiology and its interaction with the environment.
More Related Videos
12:21A Mouse Model for the Transition of Streptococcus pneumoniae from Colonizer to Pathogen upon Viral Co-Infection Recapitulates Age-Exacerbated Illness
Published on: September 28, 2022
09:20Investigating the Effects of Probiotics on Pneumococcal Colonization Using an In Vitro Adherence Assay
Published on: April 28, 2014
Related Concept Videos
01:29Pneumonia II: Pathophysiology
01:14Atypical Pneumonia
01:30Pneumonia I: Introduction
Risk Factors
Various factors influence the likelihood of developing pneumonia. Age plays a crucial role, with infants, children under two, and individuals over 65 at increased risk due to their...
01:29Pneumonia I: Introduction
01:30Pneumonia III: Complications and Assessment
01:26Bacterial Meningitis II: Pathophysiology