Say hello to Volvox zeikusii!

Volvox zeikusii

Figures 13-20 from Nozaki et al. 2019*. Light microscopy of female strain of Volvox zeikusii Nozaki. Abbreviations: c, cytoplasmic bridges; d, daughter spheroid or developing embryo; e, egg; i, individual sheath; p, pyrenoid; s, stigma.
Figs 13–19. Asexual spheroids. Fig. 13. Optical section of spheroid. Scale bar = 50 μm. Fig. 14. Optical section of spheroid stained with methylene blue. Scale bar = 50 μm. Fig. 15. Front view of somatic cells showing cytoplasmic bridges. Scale bar = 20 μm. Fig. 16. Front view of somatic cells showing individual sheaths of the gelatinous matrix stained with methylene blue. Scale bar = 20 μm. Fig. 17. Lateral optical section of somatic cells positioned in anterior region of spheroid. Scale bar = 20 μm. Fig. 18. Surface view of somatic cells positioned in anterior region of spheroid. Scale bar = 20 μm. Fig. 19. Surface view of newly formed daughter spheroid. Scale bar = 50 μm. Fig. 20. Sexual female spheroid. Scale bar = 200 μm.

Hisayoshi Nozaki and colleagues have discovered a new species of VolvoxVolvox zeikusii. Or more accurately, they have discovered new strains of an old species and decided that some of the old strains with that name are something else.

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“It was I who destroyed Ehrenberg’s theory”

Volvox globator

Volvox globator Ehrenberg (frontispiece of Julian Huxley’s The Individual in the Animal Kingdom, after A. Lang).

“The Diamond Lens” is a short story published by the Irish writer Fitz-James O’Brien in 1858. It describes the quest of an obsessed amateur microscopist for ever greater degrees of magnification, a goal for which he is willing to go to exceptional lengths. O’Brien was apparently known for mixing scientific themes with mysticism, and “The Diamond Lens” certainly fits this description. I won’t spoil it any further; interested readers can download the story for free (in several formats) from The Gutenberg Project.

As the narrator and protagonist becomes a proficient microscopist, he encounters Volvox:

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Convergence part 7: convergence in Volvox

Last year I wrote a series of posts on convergent evolution and misrepresentations of the history of the concept by proponents of intelligent design including Günter Bechly, Lee M. Spetner, Granville Sewell, and others. I didn’t intend for there to be a two-month gap before the final installment (nor am I sure this is the final installment), but here we are.

To quickly recap, I showed in the first three installments that

The Discovery Institute is producing a revisionist history. To hear them tell it, convergence is something that evolutionary biologists have either barely heard of or that they “invented” or “made up” to hide problems with the tree of life. Convergence “destroys the tree of life,” it “contradict[s] the [modern synthesis],” and it is “quite unexpected” to evolutionary biologists. All of that is a big, stinking pile of wrong. In reality, biologists since Darwin, and including Darwin, have always appreciated the importance of convergence, have written thousands of papers about it, and have included it in every evolutionary biology textbook I’m aware of.

I explained why the argument that convergence is evidence against common descent is daft, and I gave a spectacular example of convergent (or parallel) recruitment of life cycle genes in plants and brown algae. I also promised that I would write about convergent evolution in Volvox, which I have so far failed to do.

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Sola cube Micro Volvox

A soon to be former postdoc gave me one of these as a gift. It is gorgeous; the two-dimensional pictures really don’t do it justice.

Volvox carteri

Sola Cube Micro Volvox

The many strange yet intriguing forms of the microorganism, which we could not see through our daily lives, can now be put in front of our eyes with Sola cube Micro. Sola cube Micro, is a three-dimensional portrait of the microorganism, laser crystal engraved into a high transparency optical glass cube. We have worked with graphic designer to create the three-dimensional models of the portraits, by using accurate microscope photos. The two dimensional view through the microscope can now appear in three-dimensional form in front of your eyes. Enjoy the moment of gazing upon the mysterious beauty giving by the wonder of nature, with Sola cube Micro.

The spinning algae
Volvox carteri

A type of freshwater colonial green algae. The root of the name “Volvox” comes from the word volvo, meaning, “to roll” in Latin, as it spins around while it swims through the habitant. Photosynthesis can occur through the chloroplasts. The spheroid body contains two thousand somatic cells on the surface, and each cell is attached with two flagella, which pushes the body onward. Sixteen parts of gonidia grows within the main body as “the daughter Volvox” and break through the maternal colonial to form new lives. It is suggested that the unicellular organism that was relative to Chlamydomonas evolved into multicellular organism, that is, Volvox since about fifty million years ago.

Material
High transparency optical glass

Size and weight
2.0” D × 2.0” W × 2.0” H / 300g

The Sola Cube Micro collection is an eclectic set, including a radiolarian, a heliozoan, a tardigrade egg, and a phage, but as yet no Chlamydomonas.

Updates to the Volvox carteri Wikipedia page

The last time I looked at the Volvox carteri page on Wikipedia, it was pretty sad:

V carteri

Volvox carteri Wikipedia page as of December 12, 2018.

That was it; just a short intro and a section on sexual reproduction. I also had an undergraduate researcher, Sophia Sukkestad, who needed an end of semester project. I thought that if she worked on the V. carteri page, she’d learn a bit about Volvox, gain some familiarity with the relevant literature, and improve this resource for everyone.

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Volvox: a colony of cells

In 1950, a young assistant professor at Princeton University published an essay about Volvox in Scientific American, “Volvox: a colony of cells.” The essay touches on several themes that will be familiar to regular readers of Fierce Roller, including cellular differentiation, inversion, and what it means to be an individual.

The author was John Tyler Bonner, whose (much) more recent work I’ve written about previously (“Chance favors the minute animalcule: John Tyler Bonner on randomness“).

John Tyler Bonner

John Tyler Bonner, ca. 1957. Image from the Guggenheim Foundation.

Among many other contributions, Bonner was a pioneer in the development of the social amoeba (or cellular slime mold) Dictyostelium discoideum as a model system for multicellular development and cell-cell signaling. A member of the National Academy of Sciences and a fellow of the American Association for the Advancement of Science, he has published over twenty books and mountains of peer-reviewed papers.

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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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