A Library within Bacteria: Its Genome

A bacterium carries its own library of instructions called a genome. This tiny blueprint tells it how to live, grow, and adapt, and it also gives scientists valuable clues for health and technology.

What is a genome?

Inside every living organism is a library of genetic information called a genome. Like letters forming words in a book, tiny genetic letters known as nucleotides join to create genes, which act as instructions that
shape traits from eye color to flagella length. Each organism carries its own unique set of these instructions, making life wonderfully diverse.

How does a bacterial genome look like?

• Bacteria usually have their DNA in the form of a single circular chromosome, packed tightly in a part of the cell called the nucleoid.
• Unlike humans, whose DNA is arranged in straight (linear) chromosomes, bacteria’s DNA is looped into a circle.
• The image above shows John Cairns’ famous discovery, where he first captured the circular DNA of E. coli using a special method called autoradiography, which made the DNA visible on film.

Unraveling the bacterial genome

• Although scientists had visualized the bacterial genome earlier, its full function remained unknown until 1995.
• That year, Robert Fleischmann and his team became the first to completely sequence a bacterial genome, Haemophilus influenzae.
• This landmark achievement laid the foundation for genomic sequencing, the study of genes and their functions.
• It also revealed that bacteria can evolve by sharing genes through a process called horizontal gene transfer (HGT).

Horizontal gene transfer

HGT helps bacteria evolve and can affect our health. Normally, antibiotics kill bacteria, but some can share resistance genes and survive.

When bacteria share resistance genes through HGT, the trait can spread quickly, making antibiotic resistance a community-wide problem. Although this is a natural process for bacteria, its impact on humans is serious: infections once easily treated are becoming harder to cure.

Why genome matters?

Our understanding of HGT came from studying bacterial genomes, which uncovered critical challenges in modern medicine. These discoveries, made possible through genome research, showed how bacteria share resistance to antibiotics. HGT and antibiotic resistance are only two examples of the many insights gained by unraveling bacterial genomes.

Looking ahead

Biorism is committed to addressing the global challenge of antibiotic resistance. By exploring bacterial genomes as powerful tools, we aim to uncover new insights and approaches that can lead to innovative solutions for managing and overcoming this pressing threat to human health.

References:

• Cairns, John. “The Chromosome of Escherichia coli.” Cold Spring Harbor Symposia on Quantitative Biology, vol. 28, 1963, pp. 43–46. https://doi.org/10.1101/SQB.1963.028.01.011
• Fleischmann, Robert D., et al. “Whole-Genome Random Sequencing and Assembly of Haemophilus influenzae Rd.” Science, vol. 269, no. 5223, 1995, pp. 496–512. https://doi.org/10.1126/science.7542800
• Anjari, Haifa. (2016). DELIVERY OF MICROENCAPSULATED VITAMIN D BY USING COSMETIC TEXTILES. مجلة .2016.139399.mbse/بحوث التربية النوعية. .2016 .630-617 10.21608

The article is prepared by Biorism Scientist, Ms Linah, (MSc, Medical Science).