Escherichia coli, or E. coli, is an intriguing bacteria with broad scientific and practical significance. Numerous E. coli strains are essential to many different ecological niches, including the human gut, even though some of them can be harmful. Its structure and function provide insight into its flexibility, versatility, and effects on the environment and human health.
Structure
Comparing Escherichia coli (E. coli) to eukaryotic cells, the structure of bacteria is generally simpler. To fulfil all of its duties, the organisation is very effective and precise.
1. Cell Envelope
1.1 Cell Membrane
The phospholipid bilayer that envelops and isolates the cytoplasm from the outside world is called the cell membrane, often called the plasma membrane. It controls how chemicals enter and exit cells, preserving cellular homeostasis.
1.2 Cell Wall
A tough cell wall made mostly of peptidoglycan encircles the cell membrane. Shape, structural support, and defence against variations in osmotic pressure are all provided by this framework. Lipopolysaccharides (LPS) are present in the outer membrane of E. Coli‘s cell wall and might be crucial for pathogenic strain pathogenicity and immune detection.
2. Cytoplasm
2.1 Nucleoid
There is no genuine nucleus in E. Coli. Rather, its genetic material is made up of a single circular chromosome that is found in the cytoplasmic nucleoid area. The bacterial chromosome and other proteins and RNA molecules involved in transcription, packaging, and DNA replication are found within the nucleoid.
2.2 Ribosomes
Many ribosomes are scattered throughout the cytoplasm of E. coli. Messenger RNA (mRNA) is translated into functional proteins by these ribosomes, which are in charge of protein synthesis.
3. Appendages
3.1 Flagella
The lengthy, whip-like flagella that certain E. coli strains have are employed for movement. E. Coli can travel away from hazardous settings and towards favourable ones thanks to the rotation of its flagella.
3.2 Pili
Pili are shorter, hair-like projections that protrude from the surface of E. coli cells. Pili are engaged in several processes, including conjugation the exchange of genetic material between bacterial cellsand adhesion to surfaces.
4. Plasmids
Excess chromosomal DNA molecules known as plasmids are transportable by E. Coli. Small, circular DNA molecules known as plasmids reproduce apart from the bacterial chromosome. They frequently possess genes that provide benefits like virulence factors, antibiotic resistance, or metabolic capacities.
5. Periplasmic Space
The periplasmic space, which is rich in proteins and enzymes, is located between the cell wall and the membrane. Numerous biological functions, such as protein folding, cell wall formation, and food absorption, are related to this area.
The function of E. coli
1. Gut Microbiota
1.1 Commensalism
Many strains of E. coli are commensal organisms residing harmlessly in the human gut. They contribute to digestion, produce essential vitamins like vitamin K, and compete with pathogenic bacteria for resources, thereby preventing infections.
1.2 Mutualism
Some E. Coli strains create favourable connections with their hosts that support the development of the immune system and the absorption of nutrients.
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2. Pathogenesis
Although the majority of E. Coli strains are not harmful, some can result in illnesses that range from minor gastrointestinal distress to serious infections. Toxins like Shiga toxin, which are produced by pathogenic strains, can cause disorders including diarrhoea, UTIs, and even potentially fatal syndromes like hemolytic uremic syndrome (HUS).
3. Biotechnology
3.1 Research Tool
Because of its well-studied genetics and quick development, E. coli is a useful model organism for researching basic biological processes.
3.2 Bioproduction
In biotechnology, engineered strains of Escherichia coli are utilised to produce a range of chemicals, such as insulin, antibiotics, and biofuels.
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Graduated from the University of Kerala with B.Sc. Botany and Biotechnology. M.Sc. Biotechnology from the University of Kerala. Attended certificate course in Artificial Intelligence for Everyone from Deeplearning.AI, Influenza Prevention and Control from World Health Organization. Attended workshops related to Bioinformatics at the University of Kerala. 3 years of experience in website management. Experience in WordPress, Blogger, Google Analytics, and Google Search Console.
