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 wall art

I posted earlier this week about some Chlamydomonas art, just in time for the holidays. Also still available, though, are prints on canvas of Volvox aureus, in the most niche Etsy store ever:

Volvox aureus

Volvox aureus by me

These look great if I do say, and they are ready to hang. 12″ x 12″, $40 on Etsy…would make a great gift for microbe enthusiasts. I still have four of the original eight.

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/.

Volvox rousseletii in Japan

A few years back, I invited Dr. Hisayoshi Nozaki to visit the University of Montana, and to my surprise, he came. In fact, five Japanese researchers came to Missoula for the better part of a week: Dr. Nozaki, Dr. Noriko Ueki, Dr. Osami Misumi, and two undergraduate researchers. We found a speciesVolvox capensis, which had previously only ever been found in South Africa, in Ninepipe Reservoir (about an hour north of Missoula).

Now Ryosuke Kimbara and colleagues have reported another apparent long-distance traveller. In a new paper in PLoS One, they report finding Volvox rousseletii, previously reported only in Africa, in Lake Sagami in Japan. Volvox rousseletii is a member of the group of species known as Volvox section Volvox (also sometimes referred to as Euvolvox), which includes the largest species (in terms of cell number) and evolved independently of the other species in the genus Volvox.

Kimbara Fig. 1

Figure 1 from Kimbara et al. 2019. Light microscopic features of asexual spheroids in culture of Volvox rousseletii strain v-sgm-17 from Lake Sagami, Japan. (A) Mature spheroid showing daughter spheroids (d). (B-D) Part of spheroids. (B) Top view of individual sheaths (asterisks) of somatic cells stained with methylene blue. (C) Top view of somatic cells with thick cytoplasmic bridges (b). (D) Side view of elongate-ellipsoidal, anterior somatic cell with stigma (s) and pyrenoid (p) in the chloroplast. (E) Developing embryo just after inversion, showing gonidia (g) of the next generation.

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Why carteri?

It’s embarrassing, really. I’ve been studying Volvox and its relatives for 15 years now, and until today I couldn’t have told you who the most famous member of the group, Volvox carteri, was named for. Sure, I know Colemanosphaera is named for Annette Coleman, Volvox ferrisii for Patrick Ferris, and Volvox kirkiorum (“of the Kirks”) for David and Marilyn Kirk, but that’s because they were all named after I started studying Volvox.

But do you recall…the most famous algae of all?

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