【医】 拮抗性共生

Symbiosis \Sym`bi*o"sis\, n. [NL., fr. Gr. symbi`wsis a living
together, symbioy^n to live together; sy`n with + ? to live.]
(Biol.)
The living together in more or less imitative association or
even close union of two dissimilar organisms. In a broad
sense the term includes parasitism, or

{antagonistic symbiosis} or

{antipathetic symbiosis}, in which the association is
disadvantageous or destructive to one of the organisms,
but ordinarily it is used of cases where the association
is advantageous, or often necessary, to one or both, and
not harmful to either. When there is bodily union (in
extreme cases so close that the two form practically a
single body, as in the union of alg[ae] and fungi to form
lichens, and in the inclusion of alg[ae] in radiolarians)
it is called

{conjunctive symbiosis}; if there is no actual union of the
organisms (as in the association of ants with
myrmecophytes),

{disjunctive symbiosis}.
[Webster 1913 Suppl.]