soil that contained surface-sterilized Vicia seeds. The bacterial culture medium
which they used was soil extract agar, which is prepared by adding agar and maltose
to an aqueous extract of soil.
14.16 “Tier und Pflanze in Intrazellularer Symbiose” by
Paul Buchner, 1921
Paul Ernst Christof Buchner published in 1921 the first edition of his masterful
reference book on intracellular symbioses in animals. Buchner presented an understanding that on both sides of the partnership, the symbiont and its host, there must
have been acquisition of properties without which the symbiotic relationship cannot
occur.
Buchner includes a history of the discovery and understanding that many animals
which curiously seemed to produce chlorophyll did instead contain photosynthetic
microbial symbionts. Specifically, Buchner mentions photosynthetic endosymbioses
of protozoa, Anthozoa, Cnidaria, Porifera and Turbellaria, with zoochlorella (Chlorella) and zooxanthellae (dinoflagellates).
Buchner mentioned an interesting endosymbiosis by the gastropod group
opistobranchia, which is the acquisition of chloroplasts from zoochlorella by the
sea slug Elysia chlorotica. We now understand that to be an occurrence by which
chloroplasts from ingested algae Vaucheria litorea are incorporated into the host
cells through phagocytosis, after which the chloroplasts become a part of the animals
own cellular content. It would seem that the endosymbionts can be maintained if the
slug possesses appropriate nuclear DNA sequences that possibly have been acquired
by horizontal gene transfer, but otherwise continual feeding on algae is necessary for
sustaining presence of the chloroplasts. This method of acquiring chloroplasts is
termed kleptoplasy, which derives from ancient Greek and means the chloroplasts
have been stolen.
Buchner did mention an occurrence of endosymbiotic zooxanthellae in echinoderms, but I could not find subsequent information about that occurrence. Buchner
additionally mentions that unfavorable situations can result in the loss of photosynthetic symbionts, with the symbionts either being attacked and degraded or ejected
from the host. That ejection most notably causes the process which we term to be
coral bleaching.
Buchner was very much a philosophical luminary, including understand that the
bioluminescence of ctenophores was an intrinsic characteristic which occurred
within photocytes. The luminescence produced within photocytes is a reaction of
luciferin and luciferase. Photocytes are specialized cells found in a range of
multicellular animals including annelids, arthropods including insects, ctenophora,
cnidaria, and fish. Although some fungi are bioluminescent, producing the effect
called foxfire, those fungi do not have specialized luminescent cells. A contemporaneous summary of knowledge regarding bioluminescence, and the fact of their
14 Discovering the Symbiotic Nature of Microbial Life: Summarizing Milestone. . .
233
which they used was soil extract agar, which is prepared by adding agar and maltose
to an aqueous extract of soil.
14.16 “Tier und Pflanze in Intrazellularer Symbiose” by
Paul Buchner, 1921
Paul Ernst Christof Buchner published in 1921 the first edition of his masterful
reference book on intracellular symbioses in animals. Buchner presented an understanding that on both sides of the partnership, the symbiont and its host, there must
have been acquisition of properties without which the symbiotic relationship cannot
occur.
Buchner includes a history of the discovery and understanding that many animals
which curiously seemed to produce chlorophyll did instead contain photosynthetic
microbial symbionts. Specifically, Buchner mentions photosynthetic endosymbioses
of protozoa, Anthozoa, Cnidaria, Porifera and Turbellaria, with zoochlorella (Chlorella) and zooxanthellae (dinoflagellates).
Buchner mentioned an interesting endosymbiosis by the gastropod group
opistobranchia, which is the acquisition of chloroplasts from zoochlorella by the
sea slug Elysia chlorotica. We now understand that to be an occurrence by which
chloroplasts from ingested algae Vaucheria litorea are incorporated into the host
cells through phagocytosis, after which the chloroplasts become a part of the animals
own cellular content. It would seem that the endosymbionts can be maintained if the
slug possesses appropriate nuclear DNA sequences that possibly have been acquired
by horizontal gene transfer, but otherwise continual feeding on algae is necessary for
sustaining presence of the chloroplasts. This method of acquiring chloroplasts is
termed kleptoplasy, which derives from ancient Greek and means the chloroplasts
have been stolen.
Buchner did mention an occurrence of endosymbiotic zooxanthellae in echinoderms, but I could not find subsequent information about that occurrence. Buchner
additionally mentions that unfavorable situations can result in the loss of photosynthetic symbionts, with the symbionts either being attacked and degraded or ejected
from the host. That ejection most notably causes the process which we term to be
coral bleaching.
Buchner was very much a philosophical luminary, including understand that the
bioluminescence of ctenophores was an intrinsic characteristic which occurred
within photocytes. The luminescence produced within photocytes is a reaction of
luciferin and luciferase. Photocytes are specialized cells found in a range of
multicellular animals including annelids, arthropods including insects, ctenophora,
cnidaria, and fish. Although some fungi are bioluminescent, producing the effect
called foxfire, those fungi do not have specialized luminescent cells. A contemporaneous summary of knowledge regarding bioluminescence, and the fact of their
14 Discovering the Symbiotic Nature of Microbial Life: Summarizing Milestone. . .
233