TWiV 833: Grand theft kinesin

November 25, 2021

TWiV reviews Michael Worobey’s dissection of the early COVID-19 cases in Wuhan, and the discovery that herpesviruses assimilate cellular kinesin to produce motorized virus particles.

Hosts: Vincent Racaniello, Alan Dove, and Kathy Spindler

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Weekly Picks 1:21:41

KathyPower of poop
AlanUnder the Sky We Make, by Kimberly Nicholas
VincentEnzymatic amplification of beta-globing sequences

Listener Picks

PaulaReasons to be Cheerful and The Night Witches by Bruce Myles
GrantGeorge Carlin – Germs, Immune System

Intro music is by Ronald Jenkees

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9 comments on “TWiV 833: Grand theft kinesin

  1. Jeffery Biss Nov 26, 2021

    Humans do not need meat to sustain life or health and so we should end all animal based meat activities for the benefit of the victims, the nonhuman animal, and to prevent these close encounters. Of course the problem of human overpopulation should be addressed, by developing policies to get people to have no kids so that we drive the human population to well below 2 billion ASAP. The indication that our population is far too great is seen in our biomass that is 0.06 GtC whereas that of all wild mammals is 0.007 GtC. We’re almost 10X their mass! This will lead to ecosystem collapse if we don’t correct this.

  2. Phillip SanMiguel Nov 27, 2021

    About the “Herpesviruses assimilate kinesin to produce motorized viral particles” manuscript: yes, they really do use beta-lactamase as a part of their reporter system. But Vincent and Alan’s reminiscences almost certainly are of a completely different reporter, beta-galactosidase.

    Right?

    Beta-lactamase famously confers resistance to beta-lactam ring containing antibiotics such as ampicillin. Whereas beta-gal, also famously, “catalyzes the hydrolysis of beta-galactosides into monosaccharides” (wikipedia). The “Blue Colony” phenomenon derives from what happens to the substance “X-gal” when cleaved by beta-gal.

    They sound similar, “beta-lactamase” and “beta-galactosidase”. Both play critical roles in the function of many blue-white cloning vectors, such as pUC-19, pBluescript and pGem. The beta-lactamase providing the widely used amp-resistant phenotype to bacteria carrying one of these vectors, whereas beta-galactosidase activity is leveraged (although generally not fully encoded on the cloning vector itself) to give you white colonies if you have successfully inserted a vector into the polylinker area of your plasmid, or blue colonies if you have not.

    I don’t know that these methods are currently still in use, though. I was happy to abandon blue-white selection for positive-selection methods. Blue-white was always error-prone with false positives and negative possible. And Amp always seemed like the most failure-prone of antibiotics. Especially when used with super high copy vectors (like those mentioned above) you were almost guaranteed to see “satellite” colonies that were not really Amp resistant but could grow in a halo around a true Amp resistant colony that was pumping out beta-lactamase into the media surrounding it.

    Although there was a trick I picked up from a methods “Newsgroup” that involved adding some methicillin to your amp plates, which the author of that Newsgroup post insisted resulted in “no satellites, ever.” I was shocked to find out this was correct and used this methodology to great effect for several years. At some point Sigma stopped selling methicillin. Possibly trying to stem the rise of methicillin-resistant Staphlococus aureus. But by that time I no longer really needed to do the sort of work that benefited from adding methicillin to media.

  3. Steve Blake Nov 29, 2021

    A racoon dog is at least a canine – Family: canidae
    of course a different genus: Nystereutes
    species: procyoneutes