“syn” meaning “together,” and “bios” meaning “life.” Often though the word
symbiosis is understood as a mutually beneficial relationship for two organisms. In
the more general sense, it means any relationship between organisms irregardless of
whether positive or negative. The interrelationships may be any of various different
characteristics and oftentimes it is difficult to exactly differentiate between the
various types of relationship categories. Quite often these relationships between
microorganisms are more complicated than those in the animal world or even in
human society. In the following text, we will deal with some important relation
types, especially with synergism, commensalism, antibiosis, amensalism, competition, parasitism, and predation. These can exist in various combinations. It should be
stressed that there are even more sorts of mutual relationships.
15.1.1 Synergism and Syntrophy
The term synergism is derived from the Greek word “syn,” meaning “together,” and
“ergon” meaning “work,” literally “co-operation.” It denotes a situation where
certain strains of microorganisms grow better together than on their own. Synergism
and mutualism are similar in that both populations derive advantage from their
mutual, localized relationship. However, unlike mutualism, synergism represents
an association in which each of the two participants is capable of living independently of the other in their natural habitat. Therefore, the synergic relationship is
open and in that sense, one of the involved populations can be relatively easily
replaced by another one. In some situations, however, it is hard to determine if the
relationship is rather of an essential nature and therefore could be considered as
mutualism. Slater (1978) presented a synergic degradation of cyclohexane (which is
one of the most stable of cycloalkanes) by organisms of the genera Nocardia and
Pseudomonas. In that pairing, Nocardia supplies Pseudomonas with the degradation
products of cyclohexane, while Pseudomonas provides Nocardia with biotin.
Syntrophism (syntrophy), from Greek “syn” ¼ together and “trofe” ¼ nutrition, is
one of the forms of synergism and sometimes also called “cross feeding.” It is a
special form or case of symbiotic cooperation between two metabolically different
kinds of bacteria, which are mutually dependent on each other with their common
aim being to degrade a certain substrate. An example would be when one of two
kinds of bacteria makes a certain vitamin, amino acid, or a nutritional factor, which is
essential or beneficial for the life and multiplication of the other microorganisms and
vice versa. Thus, two kinds of microorganisms help each other by the synthesis of
essential growth factors. A classical case of syntrophism was described in 1940 by
Ernest Frederick Gale (1940). It is a relationship between Enterococcus faecalis and
Escherichia coli. Neither of the microbes is able to transfer the amino acid arginine
into the biogenic amin putrescine. Enterococcus faecalis can transform arginine into
the amino acid ornithine, which can then be used by E. coli to form putrescine.
Although E. coli alone is able to utilize arginine and to make agmatine by its
244
V. Klaban
symbiosis is understood as a mutually beneficial relationship for two organisms. In
the more general sense, it means any relationship between organisms irregardless of
whether positive or negative. The interrelationships may be any of various different
characteristics and oftentimes it is difficult to exactly differentiate between the
various types of relationship categories. Quite often these relationships between
microorganisms are more complicated than those in the animal world or even in
human society. In the following text, we will deal with some important relation
types, especially with synergism, commensalism, antibiosis, amensalism, competition, parasitism, and predation. These can exist in various combinations. It should be
stressed that there are even more sorts of mutual relationships.
15.1.1 Synergism and Syntrophy
The term synergism is derived from the Greek word “syn,” meaning “together,” and
“ergon” meaning “work,” literally “co-operation.” It denotes a situation where
certain strains of microorganisms grow better together than on their own. Synergism
and mutualism are similar in that both populations derive advantage from their
mutual, localized relationship. However, unlike mutualism, synergism represents
an association in which each of the two participants is capable of living independently of the other in their natural habitat. Therefore, the synergic relationship is
open and in that sense, one of the involved populations can be relatively easily
replaced by another one. In some situations, however, it is hard to determine if the
relationship is rather of an essential nature and therefore could be considered as
mutualism. Slater (1978) presented a synergic degradation of cyclohexane (which is
one of the most stable of cycloalkanes) by organisms of the genera Nocardia and
Pseudomonas. In that pairing, Nocardia supplies Pseudomonas with the degradation
products of cyclohexane, while Pseudomonas provides Nocardia with biotin.
Syntrophism (syntrophy), from Greek “syn” ¼ together and “trofe” ¼ nutrition, is
one of the forms of synergism and sometimes also called “cross feeding.” It is a
special form or case of symbiotic cooperation between two metabolically different
kinds of bacteria, which are mutually dependent on each other with their common
aim being to degrade a certain substrate. An example would be when one of two
kinds of bacteria makes a certain vitamin, amino acid, or a nutritional factor, which is
essential or beneficial for the life and multiplication of the other microorganisms and
vice versa. Thus, two kinds of microorganisms help each other by the synthesis of
essential growth factors. A classical case of syntrophism was described in 1940 by
Ernest Frederick Gale (1940). It is a relationship between Enterococcus faecalis and
Escherichia coli. Neither of the microbes is able to transfer the amino acid arginine
into the biogenic amin putrescine. Enterococcus faecalis can transform arginine into
the amino acid ornithine, which can then be used by E. coli to form putrescine.
Although E. coli alone is able to utilize arginine and to make agmatine by its
244
V. Klaban