Most commonly used bacterium for genetic engineering is?

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2016

Applied Microbiology & Infection control

Easy

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2016

Explanation

Escherichia coli (E. coli) is the most common prokaryotic model organism used in genetic engineering.
Its genetics and metabolic pathways are thoroughly studied and well-understood, making it easy to manipulate.
E. coli has a rapid growth rate, doubling its population approximately every 20 minutes under ideal conditions, which allows for quick production of desired products.
It readily accepts foreign DNA through a process called transformation and possesses numerous plasmids (small, circular DNA molecules) that are used as vectors to carry genes of interest.
Laboratory strains of E. coli are specifically engineered to be non-pathogenic and safe for handling.

Option B: Klebsiella species are often pathogenic, causing infections like pneumonia and urinary tract infections (UTIs). Their pathogenic nature and the formation of a thick capsule make them unsuitable for routine genetic engineering work.
Option C: Proteus is known for its characteristic 'swarming motility' on agar plates. This behavior causes the bacteria to spread rapidly across the surface, making it extremely difficult to isolate the single, pure colonies required for cloning and other genetic engineering techniques.
Option D: Serratia marcescens is an opportunistic pathogen, frequently implicated in hospital-acquired (nosocomial) infections. The risk of infection makes it an unsafe and impractical choice for a standard laboratory host.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Bacterial hosts in genetic engineering as background academic context rather than a clinical decision trigger.
Genetic engineering using E. coli has revolutionized medicine by enabling the mass production of therapeutic proteins. Human insulin for diabetics was one of the first and most significant products.
Other critical medical products made in E. coli include human growth hormone, interferons (for treating viral infections and some cancers), and various vaccines (e.g., Hepatitis B vaccine).
What if? - If a pathogenic strain of E. coli (like O157:H7) were used instead of a safe lab strain, it would pose a severe biohazard risk to laboratory personnel and the public, potentially causing severe gastrointestinal illness and kidney failure.

How to Approach the Question

This is a factual recall question that tests your knowledge of a fundamental concept in molecular biology and biotechnology.
First, identify the core concept: the 'workhorse' or model organism for genetic engineering.
Evaluate each option based on its known characteristics. Think about what makes a bacterium suitable for this purpose: safety (non-pathogenic), ease of growth, and how well it is understood by scientists.
Recall that E. coli is the most extensively studied prokaryote. Its name is almost synonymous with basic genetic research.
Consider the other options. Klebsiella, Proteus, and Serratia are primarily known in a clinical context as pathogens. This pathogenic nature makes them unsuitable for routine lab work.
Conclude that E. coli is the only logical answer due to its safety, rapid growth, and the vast array of genetic tools developed for it.

Concept Tested & Keywords

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