Related Experiment Video
Updated: Aug 12, 2026
06:37
Staphylococcus aureus Growth using Human Hemoglobin as an Iron Source
Published on: February 7, 2013
Heme compounds as iron sources for nonpathogenic Rhizobium bacteria
1Departamento de Bioquímica, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay.
Journal of Bacteriology
|May 1, 1997
Summary
Rhizobium meliloti 242 can utilize heme compounds like hemoglobin and leghemoglobin as iron sources, similar to animal-pathogenic bacteria. This indicates shared iron acquisition mechanisms between plant-symbiotic and pathogenic microbes.
Area of Science:
- Microbiology
- Bacterial Physiology
- Iron Metabolism
Background:
- Many bacteria, particularly animal pathogens, utilize heme compounds as essential iron sources.
- Rhizobium strains interact with host plants where heme compounds are present.
- Understanding iron acquisition in Rhizobium is crucial for plant-microbe symbiosis.
Purpose of the Study:
- To investigate if Rhizobium meliloti 242 can use hemoglobin as an iron source.
- To determine if heme, hemoglobin, and leghemoglobin serve as iron sources for R. meliloti 242 under iron limitation.
- To elucidate the relationship between different iron acquisition systems in R. meliloti 242.
Main Methods:
- Culturing Rhizobium meliloti 242 under iron-depleted conditions.
- Supplementing iron-depleted media with heme, hemoglobin, and leghemoglobin.
- Analyzing iron acquisition mutant strains of R. meliloti 242.
Main Results:
- Hemoglobin can be used as an iron source by R. meliloti 242, challenging the notion that this ability is restricted to animal pathogens.
- Heme, hemoglobin, and leghemoglobin effectively serve as iron sources for R. meliloti 242 when iron is scarce.
- Mutational analysis revealed shared components among siderophore-, heme-, hemoglobin-, and leghemoglobin-mediated iron transport systems.
Conclusions:
- Rhizobium meliloti 242 possesses versatile iron uptake mechanisms, including the utilization of host-derived heme compounds.
- The ability to use hemoglobin as an iron source is not exclusive to animal-pathogenic bacteria.
- Iron acquisition pathways for siderophores, heme, hemoglobin, and leghemoglobin in R. meliloti 242 are interconnected, likely sharing regulatory or transport components.
Related Concept Videos
02:11The Roles of Bacteria and Fungi in Plant Nutrition
Plants have the impressive ability to create their own food through photosynthesis. However, plants often require assistance from organisms in the soil to acquire the nutrients they need to function correctly. Both bacteria and fungi have evolved symbiotic relationships with plants that help the species to thrive in a wide variety of environments.
01:28Microbial Nutrition
Organisms exhibit remarkable metabolic diversity, categorized based on how they acquire energy and carbon. These strategies enable survival in various ecological niches and are essential for maintaining energy flow and nutrient cycling within ecosystems.Energy and Carbon SourcesOrganisms are classified as phototrophs or chemotrophs based on energy acquisition. Phototrophs use light as their energy source, while chemotrophs rely on oxidizing chemical compounds. Further differentiation arises...
01:22Inorganic Nitrogen Assimilation
Nitrogen is an essential element in biological systems, forming a crucial component of proteins, nucleic acids, and other cellular constituents. Many bacteria and archaea acquire nitrogen in the form of nitrate (NO₃⁻) or ammonia (NH₃), which are then assimilated into biomolecules through specific enzymatic pathways.Assimilatory Nitrate ReductionWhen nitrate enters the cell, it undergoes a two-step reduction process known as assimilatory nitrate reduction. Initially, the enzyme nitrate reductase...
01:26Microbial Interactions: Cooperation
Microbial cooperation involves beneficial interactions in which different species work together for individual or mutual advantage. These interactions can profoundly influence ecological dynamics and evolutionary processes, and they are essential to many pathogenic and symbiotic relationships.Nematode–Bacteria CooperationA striking example is the relationship between the Gram-negative bacterium Xenorhabdus nematophila and the parasitic nematode Steinernema carpocapsae. Juvenile nematodes...
01:09Microbe-Plant Interactions
Microbe-plant interactions represent a dynamic spectrum of associations shaped by intricate chemical signaling. These interactions can be neutral, beneficial, or detrimental, and profoundly influence plant physiology, growth, and ecosystem function. The plant microbiome, comprising bacteria, fungi, archaea, protists, and viruses, plays a pivotal role in mediating these effects through surface colonization, internal colonization, or systemic symbiosis.Mutualistic associations, particularly with...
01:24Microbes and Other Elemental Cycles
Microbial activity plays a pivotal role in the biogeochemical cycling of iron and manganese, especially at the redox gradients characteristic of stratified aquatic environments. These cycles are driven by microbial transformations between oxidized and reduced forms of the metals, allowing organisms to exploit them for metabolic energy and structural purposes.Iron Cycling Across Redox GradientsIn neutral, oxygen-rich surface waters, iron is predominantly found in its oxidized, insoluble ferric...