The engines fired and Apollo 8 slid silently behind the Moon. The men heard a crackle in their headsets as the radio signal to Mission Control faltered and then failed.
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2Japan halted exports to other countries for fear that agar supported their development of biowarfare weapons. A few years before, Nazi Germany allegedly tested the efficacy of biowarfare attacks with another curious microbe, Serratia marcescens, dubbed “the miracle bacterium.” According to a much-talked about report by investigative journalist Henry Wickham Steed titled “Aerial Warfare: Secret German Plans” members of a secret Luft-Gas-Angriff (Air Gas Attack) Department spread the S. marcescens in the subterranean train networks of Paris and London and measured its reach armed with Petri dishes and agar plates.
The Trent Windsurfing Club near Nottingham, England, which communicates with members using both WhatsApp and email, spells out other considerations in a 15-point list on its website.
By WWII, scientists had already begun looking at alternative gelling substances for routine use in bacteriology, but concluded that agar was still better as it is both firmer and easier to handle. Today, some specialized microbiology applications use the colloid carrageenan (extracted from red seaweed Chondrus crispus, or “Irish Moss”), a more transparent and less auto-fluorescent alternative to agar (agar emits its own background fluorescence when excited by light). However, for routine bacteriological use, carrageenan is more difficult to dissolve, requires higher concentrations, can degrade at high temperatures, and forms weaker gels, which may result in puncturing its surface during the plating of cells.