Volvox wall art giveaway!

I had eight prints made (on canvas) of a micrograph I took in grad school of Volvox aureus. They turned out much better than I expected…it’s really hard to know how the color balance of something you’re looking at on a computer screen will look when it’s printed out. I’m going to give one away by random drawing. All you have to do to enter is leave a comment identifying your favorite species (of anything; rules below).

Volvox aureus

Volvox aureus by me

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Volvox email

I got an email from a science teacher in India. This is the internet being what we thought it would be in the 1990s. I did my best to answer, but feel free to weigh in in the comments.

Dear Matthew,

This is Subhashini, I am a science teacher and a content writer for higher secondary school in India. I have gone through your research papers about Volvox. I still have few questions about Volvox. As I do not want children to get confused need some clarification. I would appreciate if you can help me in answering few questions regarding the same.

Q.1 Is Volvox unicellular, multicellular or colonial organism? Why? (I understand the evolutionary process and the relation of the same but need the explanation about specific cellularity.)

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David Kirk obituary from WUStL

David Kirk

David Kirk. Image from schoolpartnership.wustl.edu.

Washington University in St. Louis’s The Source has published an obituary of Dr. David Kirk, who died November 1, by Myra Lopez:

Kirk, who was an active and passionate member of the university community for nearly 50 years, spent a lifetime teaching developmental biology and researching the evolutionary origins of multicellular organisms. He was internationally known for his research on the spherical green alga known as Volvox carteri.

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This awkward condition

I’ve written several times about the process of inversion that occurs during the development of algae in the family Volvocaceae. Today I was going through a paper I’d read (and even written about) before, and I came across a turn of phrase I appreciated regarding inversion:

The fully cleaved embryo contains all of the cells of both types that will be present in an adult but it is inside out with respect to the adult configuration. This awkward condition is quickly corrected by a gastrulation-like inversion process.

The quote is from Benjamin Klein, Daniel Wibberg, and Armin Hallmann’s 2017 paper, “Whole transcriptome RNA-Seq analysis reveals extensive cell type-specific compartmentalization in Volvox carteri.” Setting aside that animal gastrulation and Volvox inversion may not be as similar as they are often portrayed, I love the description of inside-out colonies as “awkward”. As if they just realized they left the house with their shirt half tucked in and inversion is their way of saying “Excuse me while I get myself sorted out here.”

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Waltzing Volvox

I can’t believe I haven’t already blogged about this, but if I have it isn’t turning up in my searches. Ravi Balasubramanian’s preprint about “flocking” behavior in Volvox barberi mentioned that

V[olvox] carteri is capable of using fluid forces created by flagellar beating to form waltzing pairs.

He’s referring to a 2009 paper by Knut Drescher and colleagues in Physical Review Letters. Drescher and colleagues analyzed the physics that cause Volvox colonies to enter a hydrodynamically bound state in which two or more spheroids orbit each other in close proximity:

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Alternative patterns of explanation for major transitions

The Major Transitions in Evolution Revisited

One reason to study green algae is because they can teach us something about the evolution of multicellularity. A number of related species in the Volvocalean family form a gradation of complexity between single-celled and simple multicellular organisms. The members of this family of algae differ in size, the number of cells they produce, and whether or not there is a split between germline and somatic cells. This split is thought to be central to understanding how a new level of individuality has evolved. — Calcott 2011, p. 39.

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Volvox on Micropia

Volvox (Micropia)

Image from www.micropia.nl/en/discover/microbiology/volvox/

Micropia, the museum of microbes in Amsterdam, has a page devoted to Volvox:

Ponds and ditches are not only home to unicellular green algae, but also to multicellular forms.

Some ‘colonies’ are nothing more than a mass of single cells all doing exactly the same thing, but with the spherical volvox it’s a slightly different story. Here different cells have specialised and work together. All the cells are located on the outside of the sphere. There are cells with flagella (whip-like hairs) to help the colony move around and cells which are responsible for reproduction.

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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:

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