Two alkaliphiles, Nocardiopsis dassonvillei WA52 from Wadi Araba, Egypt
[118] and alkaliphilic Streptomyces werraensis isolated from Rajkot, India [119]
were found to be new producers of the macrolide antibiotic, erythromycin. A new
pyranonaphthoquinone antibiotic, griseusin D was isolated from the cultural fluid of
the alkaliphilic Nocardiopsis sp. It displayed strong cytotoxicity against human
leukemia cells (HL60) and modest cytotoxicity against human lung adenocarcinoma
cell lines (AGZY) and exhibited weak antifungal activity against Alternaria
alternata [120]. Two other griseusins, F and G, were obtained from an alkalophilic
Nocardiopsis sp. (YIM DT266) isolated from tin mine tailings [121]. Both these
griseusins displayed antibacterial activity toward Micrococcus luteus, S. aureus
ATCC 29213, and B. subtilis. Naphthospironone A, a novel polycyclic metabolite
with an unprecedented spiro[bicyclo[3.2.1]octene-pyran]dione ring system, was
isolated from alkalophilic Nocardiopsis sp. YIM DT266. Its complete structure
with the absolute stereochemistry was elucidated with spectroscopy, X-ray crystallography, and optical rotation data. Naphthospironone A exhibited antibiotic bioactivities with moderate cytotoxicity [122]. A broad-spectrum antifungal compound
was produced by salt-tolerant alkaliphilic Streptomyces violascens IN2–10. It was
partially characterized, and the results indicate that it belongs to the heptaene group
of polyene class antibiotics [123]. Two new pyrones named Nocardiopyrones A and
B along with other identified compounds, (three known pyridinols and
1-acetyl-β-carboline) were obtained from Nocardiopsis alkaliphila YIM-80379
that was isolated from a desert soil sample [124]. Nocardiopyrone A was active
against Pseudomonas aeruginosa, Enterobacter aerogenes, and Escherichia coli.
Nocardiopyrone B was active against P. aeruginosa, E. aerogenes, E. coli, Staphylococcus aureus, and Candida albicans.
A novel angucycline-type antibiotic, warkmycin, was isolated from the culture
filtrate of alkaliphilic Streptomyces strain Acta 2930. Its chemical structure was
elucidated by HR-MS and one-dimensional and two-dimensional NMR. The
compound inhibits the growth of Gram-positive bacteria and shows a strong
antiproliferative activity against mouse fibroblast cell line NIH-3T3 and human
cancer cell lines HepG2 and HT29 [125]. Secondary metabolites isolated from
haloalkaliphilic Streptomyces castaneoglobisporus AJ9 were structurally characterized by GC-MS analysis and confirmed as the benzoic acid derivatives of 2-hydroxy4-methoxy-6-methyl-, methyl ester. The metabolites significantly suppressed
bacterial, fungal, and viral pathogens in vitro and were able to kill the L 929 cancer
cells with an efficiency of 76% [126]. There exists a considerable interest for using
bacteriophages as antibacterial agents in medicine and agriculture. Bacteriophages
are abundant and extremely diversified and are surviving well under unfavorable
conditions including alkaline pH. However, phages do not seem to be stable for
extended period in pH values of above 9 [127]. Phages that exist in alkaline
environments should have a means to survive in the high pH habitat for long time.
However, these phages are not yet well studied, and exceptions may be found which
can be potentially used to control certain microbes. Because the structures of phages
contain a minimum of components (DNA or RNA and capsid), they can be used to
Metabolites Produced by Alkaliphiles with Potential Biotechnological. . .
183
[118] and alkaliphilic Streptomyces werraensis isolated from Rajkot, India [119]
were found to be new producers of the macrolide antibiotic, erythromycin. A new
pyranonaphthoquinone antibiotic, griseusin D was isolated from the cultural fluid of
the alkaliphilic Nocardiopsis sp. It displayed strong cytotoxicity against human
leukemia cells (HL60) and modest cytotoxicity against human lung adenocarcinoma
cell lines (AGZY) and exhibited weak antifungal activity against Alternaria
alternata [120]. Two other griseusins, F and G, were obtained from an alkalophilic
Nocardiopsis sp. (YIM DT266) isolated from tin mine tailings [121]. Both these
griseusins displayed antibacterial activity toward Micrococcus luteus, S. aureus
ATCC 29213, and B. subtilis. Naphthospironone A, a novel polycyclic metabolite
with an unprecedented spiro[bicyclo[3.2.1]octene-pyran]dione ring system, was
isolated from alkalophilic Nocardiopsis sp. YIM DT266. Its complete structure
with the absolute stereochemistry was elucidated with spectroscopy, X-ray crystallography, and optical rotation data. Naphthospironone A exhibited antibiotic bioactivities with moderate cytotoxicity [122]. A broad-spectrum antifungal compound
was produced by salt-tolerant alkaliphilic Streptomyces violascens IN2–10. It was
partially characterized, and the results indicate that it belongs to the heptaene group
of polyene class antibiotics [123]. Two new pyrones named Nocardiopyrones A and
B along with other identified compounds, (three known pyridinols and
1-acetyl-β-carboline) were obtained from Nocardiopsis alkaliphila YIM-80379
that was isolated from a desert soil sample [124]. Nocardiopyrone A was active
against Pseudomonas aeruginosa, Enterobacter aerogenes, and Escherichia coli.
Nocardiopyrone B was active against P. aeruginosa, E. aerogenes, E. coli, Staphylococcus aureus, and Candida albicans.
A novel angucycline-type antibiotic, warkmycin, was isolated from the culture
filtrate of alkaliphilic Streptomyces strain Acta 2930. Its chemical structure was
elucidated by HR-MS and one-dimensional and two-dimensional NMR. The
compound inhibits the growth of Gram-positive bacteria and shows a strong
antiproliferative activity against mouse fibroblast cell line NIH-3T3 and human
cancer cell lines HepG2 and HT29 [125]. Secondary metabolites isolated from
haloalkaliphilic Streptomyces castaneoglobisporus AJ9 were structurally characterized by GC-MS analysis and confirmed as the benzoic acid derivatives of 2-hydroxy4-methoxy-6-methyl-, methyl ester. The metabolites significantly suppressed
bacterial, fungal, and viral pathogens in vitro and were able to kill the L 929 cancer
cells with an efficiency of 76% [126]. There exists a considerable interest for using
bacteriophages as antibacterial agents in medicine and agriculture. Bacteriophages
are abundant and extremely diversified and are surviving well under unfavorable
conditions including alkaline pH. However, phages do not seem to be stable for
extended period in pH values of above 9 [127]. Phages that exist in alkaline
environments should have a means to survive in the high pH habitat for long time.
However, these phages are not yet well studied, and exceptions may be found which
can be potentially used to control certain microbes. Because the structures of phages
contain a minimum of components (DNA or RNA and capsid), they can be used to
Metabolites Produced by Alkaliphiles with Potential Biotechnological. . .
183