Volvox videos by Shigeru Gougi

Shigeru Gougi (@sgougi on Twitter) has a YouTube channel of video microscopy, including several videos of Volvox:

There’s a good mix of developmental stages here: juveniles (smaller spheroids with nothing visible inside), reproductive age asexual colonies (larger spheroids with small green dots, which are asexual reproductive cells called gonidia), mature asexual colonies (with small spheroids inside that will eventually “hatch” out to become juveniles), and pregnant females (containing yellowish zygotes that will mature into desiccation-resistant spores). I’m not sure about the species ID, but with such a large number of cells, they’re probably in the section Volvox (sometimes known as Euvolvox): [Read more…]

“Flocking” Volvox in the Regeneron Science Talent Search

Balasubramanian Fig 3 A&B

Figure 3 A&B from Balasubramanian 2018. (a) V. barberi flock where 56 colonies gathered over several minutes and rotated coherently and rapidly in the culture well. (b) Schematic of flock in panel a.

In 2017, Ravi Balasubramanian, a student from Harriton High School in Rosemont, Pennsylvania, presented a talk and a poster on “flocking” behavior in Volvox barberi at the Fourth International Volvox Meeting in St. Louis. In 2018, Balasubramanian posted a preprint of his work to bioRxiv. Now his work has earned him a place among the top 300 scholars in the Regeneron Science Talent Search 2020, “the nation’s oldest and most prestigious science and math competition for high school seniors.”

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Volvox in Brooklyn

Atlas Obscura has a new article by Sabrina Imbler, “Checking in on the Algae of a Brooklyn Reservoir with a Microbiologist“:

ON A FALL DAY, SALLY Warring had come to one of New York’s grandest stagnant pools of water to find an old friend. She is at Ridgewood Reservoir, a 50-acre wetland somewhere on the border of Brooklyn and Queens, looking for a colony of cells named Volvox.

Spoiler alert:

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Pierre Haas on Volvox inversion

Average shapes of Volvox inversion

Figure 4 from Haas et al. 2018. Average shapes of Volvox globator embryos for 10 stages of inversion (red lines), obtained from N = 22 overlaid and scaled embryo halves (lines in shades of blue on the left) and corresponding standard deviation shapes (shaded areas on the right).

One of my search alerts turned up a blog post about Volvox inversion, “Upside Down and Inside Out: Inversion in Volvox.” The author wasn’t identified at the top, but by the third paragraph it was clear that the post was written by someone with a deep familiarity with the subject:

In order to be able to swim, the colony must therefore turn itself inside out through a hole at the top of the cell sheet. This process is called inversion, and proceeds in different ways (type-A and type-B inversion) in different species. (It is not clear why Volvox evolved to have its flagella on the inside after cell division: the closely related alga Astrephomene divides into spherical colonies without the need for inversion.

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Volvox at microscopesandmonsters

Check out Martyn Kelly’s blog post about Volvox from a pond in England:

The annual Algal Training Course in Durham always has a field trip out to Cassop Pond, a small pond at the foot of the Permian Limestone escarpment in County Durham that has featured in a few of my posts over the years (see “A return to Cassop”).  This year, the group came back with some samples from the pond’s margins bearing a suspension of green dots just visible to the naked eye which, when examined under the microscope, turned out to be the colonial green alga Volvox aureus.

There’s more, including some lovely micrographs, at https://microscopesandmonsters.wordpress.com/2019/07/17/the-intricate-life-of-a-colonial-alga/.

David Kirk obituary

David Kirk

Dr. Kirk delivering the final talk at the 2007 Volvox Symposium at Washington University, an event that celebrated his retirement and his many contributions to the study of Volvox. The symposium was attended by representatives from every active Volvox lab at the time. During the symposium, Dr. Hisayoshi Nozaki announced the discovery of a new species of Volvox, Volvox kirkiorum, that he named in honor of the Kirks.

Rüdiger Schmitt and Stephen Miller have published an ‘in memoriam’ on David Kirk in the latest Phycological Society of America newsletter.

[Read more…]

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 Volvox, Volvox 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.

[Read more…]

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.