May
03
2024
If all goes well, Boeing’s Starliner capsule will launch on Monday May 6th with two crew members aboard, Butch Wilmore and Suni Williams, who will be spending a week aboard the ISS. This is the last (hopefully) test of the new capsule, and if successful it will become officially in service. This will give NASA two commercial capsules, including the SpaceX Dragon capsule, on which it can purchase seats for its astronauts.
If successful this will fulfill NASAs Commercial Crew Program (CCP) – it decided, rather than building its own next generation space capsule, it would contract with commercial companies. After an initial evaluation phase it chose two companies, Boeing and SpaceX, to get the contracts. Initially the two projects were neck and neck, but to its credit SpaceX was able to complete development first, with its Dragon 2 capsule going into service in 2020. Boeing now hopes to be the second commercial company to have a NASA approved crewed capsule.
There is obviously a lot riding on this final test flight on Monday, given the recent difficulties that Boeing has had. Its hard-earned reputation for aerospace excellence has been significantly tarnished by recent failures of its jetliners which seem to have been due to systemic problems with quality control within Boeing, and a corporate culture that no longer seems dedicated to quality and safety first. Let’s hope the space capsule division does not have the same issues.
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May
02
2024
Bacteriophages, viruses that infect bacteria, are the most abundant form of life on Earth. And yet we know comparatively little about them. But in recent years phage research has taken off with renewed interest. This is partly driven by the availability of CRISPR-based tools for studying genomes. Interestingly, CRISPR itself is a gene-editing tool that derives from bacteria and archaea, which evolved the system as a defense against viruses that infect them and alter their genome. Now we are using CRISPR to investigate those very viruses, and perhaps use that knowledge as a tool to fight bacterial infections. Bacteria may have handed us the tools to fight bacteria.
Most phage viruses are small, with genomes smaller than 200 kbp (kilo-base pairs). But a very few (93 so far) are larger than this, and known as jumbo phage viruses. The largest of these, Bacillus megaterium, is 497 kbp, which is only 87 kbp smaller than the smallest known bacterium, Mycoplasma genitalium. So essentially these are viruses that are almost as big as bacteria.
The jumbo phage viruses have been especially difficult to study for various technical reasons. For one, the filters that separate viruses from bacteria tend to trap the jumbo phages also. The genome has also been difficult to get access to. But CRISPR is changing that, giving us new tools to investigate these viruses. Researchers have recently published some interesting findings. When some jumbo viruses infect a bacterium they form a pseudonucleus that functions similar to the nucleus in eukaryotic cells, meaning that it is a walled-off section within the bacteria containing the viral genome. The purpose of forming this viral nucleus is to protect the genome from the bacterium, which will try to destroy or disable it before it can replicate.
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