Zombie Volvox on PhysOrg

Ueki & Wakabayashi Fig. 4A-C

Figure 4A-C from Ueki and Wakabayashi 2018. Ca2+-dependent changes in the direction of axonemal beating. (A) Experimental setups for observation of live or demembranated spheroids in a chamber. (B) Frames from high-speed recordings of regions near the anterior (Top) and posterior (Bottom) poles of a live spheroid. The observation using setup A was under stationary conditions in continuous light (Left) and after photostimulation (Right). (Scale bar: 100 μm.) (C) Typical sequential flagellar waveforms in a single beating cycle under each condition. Waveforms recorded as in B were traced (time interval of 1/500 s). (Scale bar: 10 μm.).

Last month, I reported on mad scientists Noriko Ueki and Ken-ichi Wakabayashi’s reanimation of dead (demembranated) Volvox rousseletii spheroids. PhysOrg is also carrying the zombie Volvox story:

[Read more…]

Volvox 2019 dates and location

The Fifth International Volvox Conference will be held at the University of Tokyo July 26-29, 2019, hosted by Professor Hisayoshi Nozaki. The tentative schedule is as follows:

Friday 26 July 2019
Registration and welcoming reception and poster set up.

Saturday 27 July 2019
Oral session and Poster session
Mixer

Sunday 28 July 2019
Oral session
Dinner party

Monday 29 July 2019
One day and/or half day trips to Volvox-field collection/algal culture collection at NIES etc. (not determined).

[Read more…]

Flagellar synchronization in Chlamydomonas

The physics is way beyond me, but a new paper by Gary Klindt and colleagues in New Journal of Physics uses Chlamydomonas as a model for flagellar synchronization:

We present a theory of flagellar synchronization in the green alga Chlamydomonas, using full treatment of flagellar hydrodynamics and measured beat patterns. We find that two recently proposed synchronization mechanisms, flagellar waveform compliance and basal coupling, stabilize anti-phase synchronization if operative in isolation. Their nonlinear superposition, however, can stabilize in-phase synchronization for suitable parameter choices, matching experimental observations.

Klindt et al. Fig. 1

Figure 1 from Klindt et al. 2017. In-phase and anti-phase synchronization. (a) In-phase synchronization at high synchronization strength, corresponding to “breast-stroke swimming” Chlamydomonas. (b) For low synchronization strength, anti-phase synchronization is stable, corresponding to a “free-style” gait.

[Read more…]

If you really want me to not trust you (a rant)

Tell me you want to discuss something contentious on the phone, then go dark when I tell you I’d rather communicate by email. This has happened to me twice lately, once with a business I’ve criticized here on the blog, and once with a member of the staff here at Georgia Tech. What is it that’s so important that you want to schedule a phone call across five time zones, but suddenly a lot less important when I ask you to put it in writing?

[Read more…]

FBI dismisses sonic weapons in Cuba “attacks”

Cuban embassy

Image credit: Getty.

That’s right, I’m using scare quotes. That’s because there is not and has never been any evidence, at least any that the public is privy to, that U.S. embassy personnel were attacked in Cuba.

It’s a near certainty that whatever happened in Cuba, it wasn’t a sonic attack, as I’ve been saying since September. After a months-long investigation, the FBI has concluded the same thing. According to the Associated Press,

Following months of investigation and four FBI trips to Havana, an interim report from the bureau’s Operational Technology Division says the probe has uncovered no evidence that sound waves could have damaged the Americans’ health, the AP has learned.

In a beautiful example of motivated reasoning, the Trump administration has shifted to an even goofier theory.

[Read more…]

More coverage of the Tetrabaena genome

Tetrabaena socialis

Tetrabaena socialis. Image by Hisayoshi Nozaki and Yoko Arakaki.

I reported last week on the publication of the Tetrabaena socialis nuclear genome by Jonathan Featherston and colleagues. Several other sources have reported on their work as well. The press release from University of Witwatersrand was reprinted by Eurekalert, Brinkwire, Archaeology News Network, and others. Shorter versions are at Worldwide News, The Everyday News, and Times Higher Education. The story has also been reported in Spanish, Russian, Czech, Vietnamese, and, of course, Afrikaans.

[Read more…]

Consumer Reports on naturopathy

Consumer Reports logo

I was pleasantly surprised to see that a new article on naturopathy in Consumer Reports largely resists the temptation to engage in false balance. While it doesn’t come right out and say you shouldn’t waste your money, the article, by Consumer Reports’ Lead Investigative Health Reporter Jeneen Interlandi, is pretty damning.

[Read more…]

Clues to the evolution of multicellularity from Tetrabaena

One development I’m excited to see among the Volvox community is an increased focus on Tetrabaena, one of the smallest and simplest of the colonial volvocine algae. The one species in this genus, Tetrabaena socialis, was classified as Gonium until 1994, when Hisayoshi Nozaki and Motomi Itoh revised it not only to a new genus but a new family, the Tetrabaenaceae.

Nozaki & Itoh 1994 Fig. 10

Figure 10 from Nozaki & Itoh 1994. Summary of the phylogenetic relationships within the colonial Volvocales inferred from cladistic analysis based on morphological data.

Their classification was based on morphological characters, but the backbone relationships, Tetrabaenaceae sister to Goniaceae + Volvocaceae, have subsequently been supported in several independent analyses using genetic data.

In 2013, very much to my surprise, Yoko Arakaki and colleagues showed that the (typically) four cells of Tetrabaena are connected by cytoplasmic bridges (this means that some of the ancestral character state reconstructions I did in grad school need to be revised). Their detailed analyses of Tetrabaena morphology and development are a valuable resource for comparative studies.

Now, in addition to the morphological data, we also have complete sequences for both organelle genomes (mitochondria and chloroplast) and for the nuclear genome. Jonathan Featherston and colleagues published the organelle genomes in 2016, and their new paper in Molecular Biology and Evolution describes the nuclear genome.

[Read more…]