Genetic code

• It was recently confirmed that a polar bear from northern Alaska has died from the disease.
• So, why are there such differences between species, and what are the implications of this polar bear’s death for the wider polar bear population, as well as other large mammals and humans?
• But if genetic testing reveals that the polar bear’s H5N1 remains poorly adapted to mammalian hosts, we might expect few other cases in polar bears.
• The consequences of failure to respond appropriately to a mammal-adapted H5N1 could be severe for polar bears – and for us.

• Backed by leading biotech investors Andreessen Horowitz, ARCH, GV, Longwood, Polaris and others
  WATERTOWN, Mass., Dec. 12, 2023 (GLOBE NEWSWIRE) -- Tome Biosciences , Inc., the programmable genomic integration company, has launched to usher in a new era of genomic medicines based on programmable genomic integration (PGI).
• “PGI represents the maturation of editing technologies, breaking current barriers in genomic medicines discovery,” said Rahul Kakkar, MD, President and Chief Executive Officer.
• “PGI is revolutionary in that we can finally reprogram the human genome with an elegance and efficiency previously unimaginable.
• Tome has an exclusive license to the core PASTE technology, which includes granted US patent numbers 11,572,556, 11,827,881 and 11,834,658.

• It is widely acknowledged that cultivated soybean emerged through the domestication of its annual ancestor in the Yellow River basin.
• To date, however, soybean genome analyses are incomplete and contain many gaps, which have so far limited in-depth investigations into its properties.
• "We've delivered the first complete Chinese soybean cultivar T2T genome," said Dr. Bo Liu, the other co-corresponding author.
• Title of original paper: A telomere-to-telomere genome assembly of Zhonghuang 13, a widely-grown soybean variety from the original center of Glycine max

• “What doesn’t kill me makes me stronger”, originally coined by Friedrich Nietzsche in 1888, is a perfect description of how bacteria develop antibiotic resistance.
• Contrary to a common belief, antibiotic resistance is not about your body becoming resistant to antibiotics.

How bacteria adapt

• The ability for bacteria to adapt lies in part with their astonishing rate of reproduction.
• While most changes are bad, sometimes they can help the bacteria grow in the presence of an antibiotic.
• This evolution of resistance can be seen by growing bacteria on a large agar plate (a nutrient support that bacteria like to grow on) with zones of increasing antibiotic levels.

They also exchange genetic material

• The other key mechanism enabling bacterial resistance is the exchange of genetic information between bacteria.
• In addition to the main chunk of DNA that encodes the bacterial genome, bacteria can host circular DNA snippets called plasmids.
• Plasmid exchange usually occurs by direct physical contact between bacteria.

4 ways bacteria resist

• Gram-positive bacteria like Staphylococcus aureus have a thick cell wall enclosing a lipid membrane.
• Antibiotics can hijack these entry routes, but bacteria can modify the cell wall, cell membrane and entry proteins to block antibiotic penetration.
• For example, bacteria increase the thickness of the cell wall to resist antibiotics like vancomycin.

• Bacteria have machinery known as efflux pumps, which regurgitate unwanted molecules from within the bacteria.
• Bacteria can alter the pump so it is more effective at removing the antibiotic, or they can simply make more pumps.
• Antibiotics, like most other drugs, generally work by blocking the function of important enzymes within the bacteria.
• If bacteria alter the target shape by changing the DNA/protein sequence, the antibiotic (key) can no longer bind to its target (lock).

Bacteria vs antibiotics

• While bacteria have developed mechanisms to resist antibiotics, these adaptations can come at a “fitness” cost.
• Bacteria may grow more slowly, or can be killed more easily by another antibiotic.
• This has led to the concept of “collateral sensitivity” to prevent or overcome resistance when treating patients, by using pairs of antibiotics.

Mark Blaskovich receives funding from a range of government, not-for-profit and commercial organisations for research into antibiotic discovery and development. He is affiliated with AAMRNet (Australian Antimicrobial Resistance Network), an organisation promoting improved care and development of antibiotics and antibiotic alternatives.