340
finger toward the need for further exploration of such habitats. Mangroves also
produce a wide array of medicinally important natural products. These are mainly
active metabolites belonging to chemical classes such as alkaloids, phenol, steroids,
terpenoids, and tannins. Two compounds, innophyllums B and P, isolated from a
mangrove-associated plant species Calophyllum inophyllum could inhibit HIV
reverse transcriptase and were active against HIV-1 in cell culture (Patil et al. 1993).
Another least explored natural resource is the deep-sea sediments. Though the
deep-sea area is geographically vast, man has very little knowledge about the organisms found there. Recent studies show that microorganisms including new actinomycetes found in the deep-sea sediments would serve as sources of novel
antimicrobials (Das et al. 2006). Marinispora is one such actinomycete, which produces macrolides called marinomycins, which are active against drug- resistant bacteria (Kwon et al. 2008).
13.8 Symbiotic Associations
Among different types of symbiotic associations (the living together of unlike
organisms), mutualism is considered the “true symbiosis.” This is the faithful and
fruitful interaction between different biological species, where survival of one species requires involvement of another. Recent investigations suggest that the true
source of bioactive compounds isolated from marine algae and other eukaryotes
would be their symbionts (Bhatnagar and Kim 2010). Symbiotic microorganisms
including prokaryotic bacteria, archaea, blue green algae (cyanobacteria), and fungi
are found in association with most marine eukaryotes. Terrestrial and marine bacteria are similar in many aspects, but since the adaptation required by a marine species, due to unique chemical and physical environments, differs significantly, ability
to produce novel compounds is thought to aid their survival in marine environment.
Symbiont of marine sponge Xestospongia sp., Micrococcus luteus is found to have
antimicrobial activity (Bultel-Ponce et al. 1999). Other examples of antimicrobials
isolated from symbionts of marine species include quinolones and phosphatidyl
glyceride isolated from a Pseudomonas sp. which are associated with Homophymia
sp. (sponge) (Bultel-Ponce et al. 1999).
13.9 Novel Technologies in Antimicrobial Discovery
Advances in technology have positively contributed to identification of novel antimicrobials from a variety of sources. Understanding the chemical structure, mechanism of drug-host interactions, and the possibilities of intelligent modifications that
enhance efficacy are equally important as discovery of a novel compound. Thanks
to the branches of science such as metagenomics, nanotechnology, metabolomics,
synthetic biology, bioinformatics, and sociomicrobiology and relatively newer techniques such as next-generation DNA sequencing, novel microbial culture methods,
mass spectrometry, imaging mass spectrometry (IMS), NMR spectroscopy, and
Lini Nirmala and D.P. Zyju
finger toward the need for further exploration of such habitats. Mangroves also
produce a wide array of medicinally important natural products. These are mainly
active metabolites belonging to chemical classes such as alkaloids, phenol, steroids,
terpenoids, and tannins. Two compounds, innophyllums B and P, isolated from a
mangrove-associated plant species Calophyllum inophyllum could inhibit HIV
reverse transcriptase and were active against HIV-1 in cell culture (Patil et al. 1993).
Another least explored natural resource is the deep-sea sediments. Though the
deep-sea area is geographically vast, man has very little knowledge about the organisms found there. Recent studies show that microorganisms including new actinomycetes found in the deep-sea sediments would serve as sources of novel
antimicrobials (Das et al. 2006). Marinispora is one such actinomycete, which produces macrolides called marinomycins, which are active against drug- resistant bacteria (Kwon et al. 2008).
13.8 Symbiotic Associations
Among different types of symbiotic associations (the living together of unlike
organisms), mutualism is considered the “true symbiosis.” This is the faithful and
fruitful interaction between different biological species, where survival of one species requires involvement of another. Recent investigations suggest that the true
source of bioactive compounds isolated from marine algae and other eukaryotes
would be their symbionts (Bhatnagar and Kim 2010). Symbiotic microorganisms
including prokaryotic bacteria, archaea, blue green algae (cyanobacteria), and fungi
are found in association with most marine eukaryotes. Terrestrial and marine bacteria are similar in many aspects, but since the adaptation required by a marine species, due to unique chemical and physical environments, differs significantly, ability
to produce novel compounds is thought to aid their survival in marine environment.
Symbiont of marine sponge Xestospongia sp., Micrococcus luteus is found to have
antimicrobial activity (Bultel-Ponce et al. 1999). Other examples of antimicrobials
isolated from symbionts of marine species include quinolones and phosphatidyl
glyceride isolated from a Pseudomonas sp. which are associated with Homophymia
sp. (sponge) (Bultel-Ponce et al. 1999).
13.9 Novel Technologies in Antimicrobial Discovery
Advances in technology have positively contributed to identification of novel antimicrobials from a variety of sources. Understanding the chemical structure, mechanism of drug-host interactions, and the possibilities of intelligent modifications that
enhance efficacy are equally important as discovery of a novel compound. Thanks
to the branches of science such as metagenomics, nanotechnology, metabolomics,
synthetic biology, bioinformatics, and sociomicrobiology and relatively newer techniques such as next-generation DNA sequencing, novel microbial culture methods,
mass spectrometry, imaging mass spectrometry (IMS), NMR spectroscopy, and
Lini Nirmala and D.P. Zyju