Related Experiment Video
Updated: May 29, 2026
07:56
A Set of In Situ Informed Simulated Medium Formats for Culturing Environmentally Acquired Anaerobic Microorganisms
Published on: January 12, 2024
Insights into the pH up-shift responsive mechanism of Acidithiobacillus ferrooxidans by microarray transcriptome
Qian Li1, Youhua Ren, Guanzhou Qiu
1School of Minerals Processing and Bioengineering, Central South University, Changsha, China.
Folia Microbiologica
|September 10, 2011
Summary
Acidithiobacillus ferrooxidans exhibits significant gene expression changes during pH up-shift stress, indicating self-protection mechanisms. Key metabolic pathways like sulfur assimilation and CO2 fixation were induced, while nitrogen fixation was repressed.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Acidithiobacillus ferrooxidans is a crucial bacterium in bioleaching and environmental processes.
- Understanding its response to environmental stressors like pH changes is vital for optimizing industrial applications and ecological roles.
- Previous studies have not fully elucidated the molecular mechanisms governing A. ferrooxidans' adaptation to pH up-shift stress.
Purpose of the Study:
- To investigate the comprehensive molecular response of Acidithiobacillus ferrooxidans to a pH up-shift.
- To identify specific genes and metabolic pathways involved in the adaptation and self-regulation of A. ferrooxidans under stress conditions.
- To provide insights into the bacterium's survival strategies and homeostasis maintenance.
Main Methods:
- Whole-genome DNA microarrays were employed to analyze temporal gene expression profiles.
- A. ferrooxidans cultures were subjected to a controlled pH up-shift.
- Gene expression levels were monitored over a 160-minute period.
Main Results:
- Approximately 30% of genes were upregulated, and 14% were downregulated, revealing extensive transcriptional changes.
- Genes related to membrane components, phosphate metabolism, sulfur assimilation, and CO2 fixation were significantly induced.
- Hydrogen uptake genes were induced, while nitrogen fixation genes were repressed, suggesting roles in pH homeostasis.
Conclusions:
- A. ferrooxidans demonstrates robust self-protection and self-regulation capabilities in response to pH up-shift stress.
- The observed differential gene expression highlights the bacterium's adaptive strategies involving membrane regulation, nutrient metabolism, and energy conservation.
- Hydrogen uptake and repressed nitrogen fixation are likely key contributors to maintaining cytoplasmic pH homeostasis.
Related Concept Videos
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...
01:19Acid Mine Drainage
Mining activities that disturb sulfide-rich rocks, particularly those containing pyrite (FeS₂), initiate a cascade of geochemical and microbiological processes with serious environmental implications. When exposed to air and water, pyrite undergoes oxidation, releasing sulfate, ultimately forming sulfuric acid and mobilizing heavy metals into surrounding water systems. This phenomenon, known as acid mine drainage (AMD), results in low pH waters laden with toxic elements that threaten aquatic...
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...
01:27Microbial Leaching
Microbial leaching, also known as bioleaching, is an environmentally favorable method for extracting metals from low-grade ores using specific microorganisms. This biotechnological approach is particularly valuable for mining operations targeting copper, gold, and uranium, where traditional extraction methods may be economically or environmentally impractical.Copper Leaching and Microbial CatalysisIn copper bioleaching, crushed ore is arranged into heaps and irrigated with a dilute sulfuric...
01:15Metabolism of Chemolithotrophs
Chemolithotrophs are microorganisms that obtain energy by oxidizing inorganic molecules such as hydrogen gas (H₂), ammonia (NH₃), reduced sulfur compounds (H₂S, S²⁻), and ferrous iron (Fe²⁺). Unlike heterotrophic organisms that rely on organic carbon, chemolithotrophs transfer electrons from these inorganic donors to the electron transport chain (ETC), generating a proton motive force (PMF) that drives ATP synthesis through oxidative phosphorylation. However, because inorganic electron donors...
01:21Hyperthermophilic Bacteria
Domain Bacteria includes some unique hyperthermophilic species. They exhibit remarkable adaptations that enable survival in extreme environments.Thermotoga species are rod-shaped, gram-negative, non-sporulating hyperthermophiles that form a sheath-like envelope called a toga. They ferment sugars or starch, producing lactate, acetate, CO₂, and H₂, and can also grow via anaerobic respiration using H₂ and ferric iron. Found in hot springs and hydrothermal vents, over 20% of their genes show strong...