The vocabulary of the blob (Physarum polycephalum) borrows from cell biology, historical mycology, and ethology. Here are the essential terms—listed alphabetically.
A
Agar
A polysaccharide extracted from red algae, used as a culture medium. ⚠️ It does not feed the blob: it is a gel where it moves and remains moist. Its food is rolled oats. It is dosed at 1.5 g per 100 mL of water (1.5%). Our 10 g refill, a laboratory-quality (bacteriological) agar, therefore allows for the preparation of about 660 mL of agar gel, poured to a thickness of 4 mm—which is about 25 90 mm dishes.
Amoeba
A eukaryotic cell without a rigid wall, which moves using pseudopods. The blob is a giant amoeba.
Amoebozoa
The large group of eukaryotes to which the blob belongs. It is not a "kingdom": it is a supergroup, at an evolutionary distance from animals and fungi comparable to each other. Molecular clocks date this lineage back to more than a billion years ago. Caution: saying "Amoebozoa are never pathogenic" is false (see Entamoeba histolytica)—it is Physarum polycephalum in particular that is not.
ATP
Adenosine triphosphate, a universal energy molecule. The blob synthesizes it through oxidative phosphorylation.
B
Biofilm
A microbial community on a surface. The bacteria that compose it are part of the blob's menu.
Blob
The French vernacular name for Physarum polycephalum. Popularized in 2019 during the exhibition at the Parc Zoologique de Paris.
C
Chitin
A polysaccharide constituting the wall of fungi. The blob does not have any.
Cytoplasm
Intracellular content. In the blob, it flows in both directions within the venous network (back-and-forth cyclosis), reversing its direction every 1 to 2 minutes.
Life cycle
Sclerotium → plasmodium → sporulation → spores → amoebae → gamete fusion → new plasmodium. Detailed article.
D
De Bary, Anton
German botanist (1831–1888) who, in 1859, separated myxomycetes from fungi by relating them to animal-like organisms (his "Mycetozoa"). The revised monograph was published in 1864.
Diploid
A cellular state with two sets of chromosomes. The plasmodium is diploid.
Dormancy
A state of slowed life. The sclerotium is the dormant form.
E
Élève ton blob ("Raise your blob")
A pedagogical project by CNES + CNRS launched in 2021 during Thomas Pesquet's Alpha mission. About 4,500 candidate institutions, with ~2,000 selected. It was not a scientific experiment: 4 samples in orbit, no replication, no peer-reviewed publication—the goal was to have students manipulate them, and that is perfectly fine.
F
Fusion
Two compatible plasmodia can fuse into a single individual. ⚠️ This is not reproduction: sexual reproduction occurs at the stage where haploid amoebae fuse into a zygote.
G
Chemical gradient
A gradual variation in a chemical concentration. The blob detects its food through chemotaxis.
H
Haploid
A cellular state with a single set of chromosomes. Amoebae are haploid.
Heterotroph
An organism that consumes the organic matter of other living beings. The blob is heterotrophic.
L
Maze
The benchmark experiment by Nakagaki (2000, Nature). The apparatus is included in the Kit Blob Lab.
M
Major Tom
Our heroic strain: Physarum polycephalum LU352, the exact strain sent to the ISS by CNES in 2021 (confirmed by CNES).
External memory
The blob's ability to navigate using the mucus trails it leaves behind, which it subsequently avoids (Smith-Ferguson et al., 2017). The "memory" is therefore in the environment, not in the cell.
Microgravity
A state of near-zero gravity (ISS). Blobs were observed there in 2021 as part of "Élève ton blob."
Mycelium
A network of fungal filaments. The blob does not have a mycelium (cf. Blob vs fungus).
Myxogastria
The accepted name today for the blob's group. "Myxomycetes" is the traditional synonym. Full classification chain: Eukaryota › Amoebozoa › Evosea › Eumycetozoa › Myxogastria › Physarales › Physaraceae › Physarum polycephalum.
Myxomycete
Historical name of the group, from the Greek myxa (mucus) + mykês (fungus)—a misleading etymology, since it is not a fungus. Today we prefer the term Myxogastria.
N
Nakagaki, Toshiyuki
Japanese biologist (Hokkaido). Author of the maze experiments (2000) and the Tokyo network (2010).
Nucleus
Organelle containing DNA. The plasmodium contains millions of nuclei within a single cell.
O
Network optimization
The blob's ability to connect food sources through a network that offers a good compromise between total length and robustness (Tero et al., 2010, Science).
P
Pesquet, Thomas
French astronaut. ⚠️ He did not bring the blobs: he took off on April 23, 2021, without them. The 4 sclerotia arrived on board via the Cygnus cargo ship on August 12, 2021, and he woke them up on September 2, 2021. Full article.
Petri (dish)
A sterile container for culturing the blob. Our kits use three formats depending on the use: 60 mm (revival and subculturing), 90 mm (growth and routine experiments, including the maze), 120 mm square (the Tokyo network, which requires a square support).
Phagocytosis
The blob's mode of nutrition: it physically engulfs its food.
Physarum polycephalum
The scientific name of the blob. From the Greek: physarum (vesicle) + polycephalum (many heads). Described by Schweinitz in 1822.
Plasmodium
The active form of the blob: a bright yellow, mobile, giant cell.
R
Ranks (classification)
Classic Linnaean ranks (kingdom, phylum, class...) no longer truly apply to eukaryotes: the reference classification (Adl et al., 2019) has abandoned them in favor of a hierarchy of nested groups. That is why we do not speak of "kingdom Amoebozoa," but of a supergroup.
Reid, Chris
Australian biologist, specialist in Physarum behavior. Co-author of Smith-Ferguson et al. (2017), the reference study on externalized spatial memory: the blob navigates using the mucus trails it leaves behind, which it subsequently avoids.
S
Saprophyte
A mode of nutrition in fungi, via absorption. The blob is NOT a saprophyte: it uses phagocytosis.
Sclerotium
The dormant form of the blob: a dry, yellow crust. Kept dry and away from light, it remains viable for at least a year, often much longer. This is what you receive in your BlobFarm kit.
Sclerotization
The process of transitioning from an active plasmodium to the dormant form.
Slime mold
An English term for myxomycete. Literally "viscous mold." Inappropriate: it is not a mold.
Spore
A reproductive cell produced during sporulation.
Sporulation
Formation of sporocysts and production of spores (via meiosis), which will release haploid amoebae.
Stentor
A genus of unicellular ciliated protozoa. Often compared to the blob in cellular ethology.
T
Tokyo Subway
The reference experiment by Tero, Nakagaki et al. (2010, Science). The apparatus is included in the Kit Blob Lab.
Mating type
A category of reproductive compatibility. In Physarum polycephalum, compatibility relies on three loci: matA (16 alleles) × matB (15) × matC (3) = 720 possible combinations (Kawano, Kuroiwa & Anderson, 1987, Journal of General Microbiology, 133(9), 2539-2546). ⚠️ This is not a record for living organisms: the fungus Schizophyllum commune is said to have more than 23,000.
U
Unicellular
Consisting of a single cell. The blob remains unicellular even though it can cover, in culture, a surface visible to the naked eye much larger than a Petri dish.
V
Plasmodial vein
A cytoplasmic channel of the plasmodium. The venous network is the most photogenic aspect of the blob.
Growth speed
The front of the blob advances at a few millimeters to a few centimeters per hour, the faster the hungrier it is. It depends on the temperature, the strain, and the state of the substrate—be wary of single numbers quoted everywhere.
Z
Zygote
A diploid cell resulting from the fusion of two haploid gametes. The starting point for a new plasmodium.
Glossary written by the BlobFarm team. See also our complete scientific sources.
