Part E | 27.1
664 Part E Marine Microbiology and Biotechnology
The journey to establish that marine actinomycetes
are unique and a source of diverse secondary metabolites has been long but it serves to illustrate that unique
environments in particular the marine ones produce
unique species and confirms that such natural product sources of new biologically active compounds will
continue to be productive [27.1, 3, 8, 9]. Unique biosynthetic enzymes discovered from marine-derived bacteria also emerge as powerful biocatalysts in medicinal
chemistry and total synthesis. The increasingly interdisciplinary field of marine natural product chemistry
provides impetus for future developments in medicine,
chemistry, and biology [27.10].
Pioneering work dates back to 1970s when Okami
and co-workers at the Institute of Microbial Chemistry in Tokyo detected bioactive actinomycetes from
shallow- and deep-water sediments from the coasts of
Japan [27.11]. One of these bioactive actinomycetes
was Chainia purpurogena SS-228, isolated from mud
samples obtained from Sagami Bay, producer of a benzanthraquinone antibiotic [27.8, 12]. The search for
marine bioactive actinomycetes continued and from
the mid-1980s in Fenical’s laboratory resulted in the
isolation of the first true marine obligate bacteria in
1991 [27.8, 13]. A new marine actinomycete cluster
was reported by Mincer et al. [27.14] and the genus
Salinispora was established as seawater obligate marine
actinomycete in 2005 [27.15]. In subsequent studies
over 1000 Salinispora strains have been isolated from
sediments collected from subtropical Atlantic, the Red
Sea and the Sea of Cortez all requiring seawater and
sodium for growth. In a study of a collection of 288
samples from around the island of Guam, actinomycete
growth was obtained with 223 (77%) of samples. The
most abundant actinomycetes recovered belonged to the
genus Salinispora with 58% of the 984 strains obtained
in pure culture assigned to this genus [27.16].
The species of Salinispora have been shown to be
producers of potent compounds [27.17–21] and the
genus has been the forerunner of the identification of
other unique marine genera. These efforts resulted in
the development of new approaches to sample the deep
oceans. An autonomous bounce corer was developed
that allowed replicate sampling from sediment cores
from surface vessels [27.20].
The genus Salinispora has become a model concept to address species and species-specific metabolite
production [27.21–23]. Salinispora tropica and Salinispora arenicola have been described as new species and
the description of another new species Salinispora pacifica is underway [27.23, 24]. The close phylogenetic
relationships among the three species is shown by the
genus as a whole having 99% 16S rRNA (ribosomal
ribonucleic acid) sequence identity and the pair-wise
comparison differ by as few as five nucleotides [27.23].
The three currently known species of Salinispora cooccur at six widely separated and distinct locations and
the strains produce different compounds [27.25].
Bioactive compounds reported from this genus
include: arenimycin, an antibiotic effective against
rifampin- and methicillin-resistant Staphylococcus aureus from S. arenicola [27.26] as well as cyanosporasides A and B, chloro- and cyano-cyclopenta[˛]indene
glycosides from S. pacifica [27.27].
Besides Salinispora there are other new bioactive
marine genera described to date, examples include
Salinibacterium [27.28], Sciscionella [27.29], Serinicoccus [27.30], and Demequina [27.31].
Marine-sourced actinomycetes have been shown to
be a remarkable resource for the discovery of natural
products showing potent biological activities. New antibiotics have been reported from marine actinomycetes
such as the streptogramin antibiotic etamycin derived
from a marine coastal-line-associated actinomycete
from Fiji produced activity against methicillin resistant
S. aureus [27.32]. Caboxamycin, a new antibiotic of the
benzoxazole family has been isolated from the deepsea Streptomyces species [27.33]. Indole alkaloid marine natural products have also been shown to contain
anticancer activity [27.34] and three new chlorinated
dihydroquinones were reported from a marine-derived
streptomycete species by Soria-Mercado et al. [27.35].
Other examples include: thiocoraline, a new anticancer drug produced by a marine Micromonospora
strain [27.4, 36], which is under preclinical assessment and the antiviral drug cyclomarin A produced
by a marine Streptomyces strain [27.4, 37]. Chandrananimycins A, B, and C with anticancer activity
were isolated from a marine-derived Actinomadura
species [27.38]. Abyssomicin A–C polycyclic antibiotics from a marine Verrucosispora strain inhibit paminobenzoic acid/tetrahydrofolate biosynthesis pathway by blocking the p-aminobenzoate formation in
the bacterial folate biosynthetic pathway [27.39]. The
antimalarial potential of marine actinomycete-derived
compounds has also recently been reported [27.40].
27.1.2 Novel Chemistry
from Marine Actinomycetes
Marine-derived actinomycetes have been a prolific
source of natural products containing diverse chemi-
664 Part E Marine Microbiology and Biotechnology
The journey to establish that marine actinomycetes
are unique and a source of diverse secondary metabolites has been long but it serves to illustrate that unique
environments in particular the marine ones produce
unique species and confirms that such natural product sources of new biologically active compounds will
continue to be productive [27.1, 3, 8, 9]. Unique biosynthetic enzymes discovered from marine-derived bacteria also emerge as powerful biocatalysts in medicinal
chemistry and total synthesis. The increasingly interdisciplinary field of marine natural product chemistry
provides impetus for future developments in medicine,
chemistry, and biology [27.10].
Pioneering work dates back to 1970s when Okami
and co-workers at the Institute of Microbial Chemistry in Tokyo detected bioactive actinomycetes from
shallow- and deep-water sediments from the coasts of
Japan [27.11]. One of these bioactive actinomycetes
was Chainia purpurogena SS-228, isolated from mud
samples obtained from Sagami Bay, producer of a benzanthraquinone antibiotic [27.8, 12]. The search for
marine bioactive actinomycetes continued and from
the mid-1980s in Fenical’s laboratory resulted in the
isolation of the first true marine obligate bacteria in
1991 [27.8, 13]. A new marine actinomycete cluster
was reported by Mincer et al. [27.14] and the genus
Salinispora was established as seawater obligate marine
actinomycete in 2005 [27.15]. In subsequent studies
over 1000 Salinispora strains have been isolated from
sediments collected from subtropical Atlantic, the Red
Sea and the Sea of Cortez all requiring seawater and
sodium for growth. In a study of a collection of 288
samples from around the island of Guam, actinomycete
growth was obtained with 223 (77%) of samples. The
most abundant actinomycetes recovered belonged to the
genus Salinispora with 58% of the 984 strains obtained
in pure culture assigned to this genus [27.16].
The species of Salinispora have been shown to be
producers of potent compounds [27.17–21] and the
genus has been the forerunner of the identification of
other unique marine genera. These efforts resulted in
the development of new approaches to sample the deep
oceans. An autonomous bounce corer was developed
that allowed replicate sampling from sediment cores
from surface vessels [27.20].
The genus Salinispora has become a model concept to address species and species-specific metabolite
production [27.21–23]. Salinispora tropica and Salinispora arenicola have been described as new species and
the description of another new species Salinispora pacifica is underway [27.23, 24]. The close phylogenetic
relationships among the three species is shown by the
genus as a whole having 99% 16S rRNA (ribosomal
ribonucleic acid) sequence identity and the pair-wise
comparison differ by as few as five nucleotides [27.23].
The three currently known species of Salinispora cooccur at six widely separated and distinct locations and
the strains produce different compounds [27.25].
Bioactive compounds reported from this genus
include: arenimycin, an antibiotic effective against
rifampin- and methicillin-resistant Staphylococcus aureus from S. arenicola [27.26] as well as cyanosporasides A and B, chloro- and cyano-cyclopenta[˛]indene
glycosides from S. pacifica [27.27].
Besides Salinispora there are other new bioactive
marine genera described to date, examples include
Salinibacterium [27.28], Sciscionella [27.29], Serinicoccus [27.30], and Demequina [27.31].
Marine-sourced actinomycetes have been shown to
be a remarkable resource for the discovery of natural
products showing potent biological activities. New antibiotics have been reported from marine actinomycetes
such as the streptogramin antibiotic etamycin derived
from a marine coastal-line-associated actinomycete
from Fiji produced activity against methicillin resistant
S. aureus [27.32]. Caboxamycin, a new antibiotic of the
benzoxazole family has been isolated from the deepsea Streptomyces species [27.33]. Indole alkaloid marine natural products have also been shown to contain
anticancer activity [27.34] and three new chlorinated
dihydroquinones were reported from a marine-derived
streptomycete species by Soria-Mercado et al. [27.35].
Other examples include: thiocoraline, a new anticancer drug produced by a marine Micromonospora
strain [27.4, 36], which is under preclinical assessment and the antiviral drug cyclomarin A produced
by a marine Streptomyces strain [27.4, 37]. Chandrananimycins A, B, and C with anticancer activity
were isolated from a marine-derived Actinomadura
species [27.38]. Abyssomicin A–C polycyclic antibiotics from a marine Verrucosispora strain inhibit paminobenzoic acid/tetrahydrofolate biosynthesis pathway by blocking the p-aminobenzoate formation in
the bacterial folate biosynthetic pathway [27.39]. The
antimalarial potential of marine actinomycete-derived
compounds has also recently been reported [27.40].
27.1.2 Novel Chemistry
from Marine Actinomycetes
Marine-derived actinomycetes have been a prolific
source of natural products containing diverse chemi-