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ABSTRACT: The rheological properties of an exopolysaccharide, EPS-R, produced by the marine bacteriumHahella chejuensis strain 96CJ10356 were investigated. The E24 of 0.5% EPS-R was 89.2%, which was higher than that observed in commercial polysaccharides such as xanthan gum (67.8%), gellan
gum (2.01%) or sodium alginate (1.02%). Glucose and galactose are the main sugars in EPS-R, with a molar ratio of ∼1∶6.8,
xylose and ribose are minor sugar components. The average molecular mass, as determined by gel filtration chromatography,
was 2.2×103 KDa. The intrinsic viscosities of EPS-R were calculated to be 16.5 and 15.9 dL/g using the Huggins and Kraemer equations,
respectively, with a 2.3 dL/g overlap. In terms of rigidity, the conformation of EPS-R was similar to that of caboxymethyl
cellulose (5.0×10−2). The rheological behavior of EPS-R dispersion indicated that the formation of a structure intermediate between that of a
random-coil polysaccharide and a weak gel. The aqueous dispersion of EPS-R at concentrations ranging from 0.25 to 1.0% (w/w)
showed a marked shear-thinning property in accordance with Power-law behavior. In aqueous dispersions of 1.0% EPS-R, the consistency
index (K) and flow behavior index (n) were 1,410 and 0.73, respectively. EPS-R was stable to pH and salts.
Biotechnology and Bioprocess Engineering 04/2012; 9(5):405-413. · 1.28 Impact Factor
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ABSTRACT: Ten strains of marine bacteria (SCH0401–SCH0410) were isolated from Ayajin, the east coast of South Korea. In spectrophotometer
based chemotaxis assay the ethyl acetate extract (300μg) of SCH0402 decreased the optical density (OD) of the motile target
strains SCH0401, SCH0402, SCH0407 and SCH0408 by two to six times when compared to control. Tributyltin oxide (TBTO) decreased
the OD of all target strains by only two times. The most active strain SCH0402 was identified as Shewanella oneidensis by using 16S rDNA gene sequence analysis. Similarly, the target motile strains SCH0401, SCH0402, SCH0407 and SCH0408 were
identified as Alteromonas marina, Shewanella oneidensis, Roseobacter gallaeciensis and Bacillus atrophaeus, respectively. The growth inhibition zone produced by the test bacterial extracts against the target strains were three to
eight times smaller when compared to that of TBTO. Even though, SCH0402 showed six times weaker antibacterial activity, the
repellent activity was three times stronger than TBTO. Therefore, the higher negative chemotactic activity would be better
to select eco-friendly antifouling compounds than the other antibacterial activities.
Hydrobiologia 04/2012; 568(1):417-423. · 1.78 Impact Factor
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ABSTRACT: Unique physiological and metabolic properties of Arctic mosses are responsible for their acclimation to the inclement polar
environment. To perform transcriptome analysis of an Arctic moss species adapted to polar conditions, we constructed a complementary
DNA (cDNA) library using total high-quality RNA extracted from the moss species Aulacomnium turgidum. The library consisted of 1.81×106 of independent clones with 97.41% of recombinants. A total of 509 cDNA clones were sequenced. After eliminating poor quality
sequences, vector trimming and clustering, 360 unigenes consisting of 33 contigs and 327 singletons were identified. Basic
Local Alignment Search Tool X searches generated 245 significant hits (E value <10−5). For further Gene Ontology analysis, 158 unigenes were annotated and classified with terms for molecular function, biological
process and cellular component. Among the expressed sequence tags, seven genes were selected based on their putative roles
in stress response, and they showed enhanced transcripts level under various abiotic stresses such as low temperature, heat
and high-salinity. Also, two rare-cold-inducible genes showed different expression patterns under low temperature and UV-B
treatment, indicating their distinct roles in adaptation to Arctic environment. Although experiments have been conducted on
a limited scale, this study provides useful information for better understanding the mechanism of stress acclimation of polar
mosses and material basis for potential genomic modification for higher plants to increase stress tolerance.
KeywordsArctic moss-
Aulacomnium turgidum
-Expressed sequence tags (ESTs)-Gene Ontology (GO)
Polar Biology 04/2012; 33(5):617-626. · 1.66 Impact Factor
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ABSTRACT: The expression of cell adhesion molecules on vascular smooth muscle cells is central to leukocyte recruitment and progression of atherosclerotic disease. Ohioensin F, a chemical compound of the Antarctic moss Polyerichastrum alpinum, exhibited inhibitory activity against protein tyrosine phosphatase 1B and antioxidant activity. However, published scientific information regarding other biological activities and pharmacological function of ohioensin F is scarce. In the present study, we aimed to examine the in vitro effects of ohioensin F on the ability to suppress TNF-α-induced adhesion molecule expression in vascular smooth muscle cells (VSMCs).
The inhibitory effect of ohioensin F on TNF-α-induced upregulation in expression of adhesion molecules was investigated by enzyme-linked immunosorbent assay, cell adhesion assay, RT-PCR, western blot analysis, immunofluorescence, and transfection and reporter assay, respectively.
Pretreatment of VSMCs with ohioensin F at nontoxic concentrations of 0.1-10 μg/ml dose-dependently inhibited TNF-α-induced expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1). In addition, ohioensin F suppressed adhesion of THP-1 monocytes to TNF-α-stimulated VSMCs. Ohioensin F reduced TNF-α-induced production of intracellular reactive oxygen species (ROS) and phosphorylation of p38, ERK, JNK and Akt. Finally, ohioensin F inhibited TNF-α-induced CAM mRNA expression and NK-κB translocation.
These results suggest a new mechanism of ohioensin F's anti-inflammatory action, owing to the negative regulation of TNF-α-induced adhesion molecule expression, monocyte adhesion and ROS production in vascular smooth muscle cells. Our finding also supports ohioensin F as a potential pharmacological, anti-inflammatory molecule that has a protective effect on the atherosclerotic lesion.
Life sciences 03/2012; 90(11-12):396-406. · 2.56 Impact Factor
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ABSTRACT: Up-regulation of cell adhesion molecules on vascular smooth muscle cells (VSMCs) and leukocyte recruitment to the vascular wall contribute to vascular inflammation and atherosclerosis. Stereocalpin A, a chemical compound of the Antarctic lichen Ramalina terebarata, displays tumoricidal activity against several different tumor cell types. However, other biological activities of stereocalpin A and its molecular mechanisms remain unknown. In this study, our work is directed toward studying the in vitro effects of stereocalpin A on the ability to suppress the expression of adhesion molecules induced by TNF-α in vascular smooth muscle cells. Pretreatment of VSMCs for 2h with stereocalpin A at nontoxic concentrations of 0.1-10 μg/ml inhibited TNF-α-induced adhesion of THP-1 monocytic cells and expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1). Stereocalpin A reduced TNF-α-induced production of intracellular reactive oxygen species (ROS) and phosphorylation of p38, ERK, JNK and Akt. Stereocalpin A also inhibited NK-κB activation induced by TNF-α. Moreover, stereocalpin A inhibited TNF-α-induced ΙκΒ kinase activation, subsequent degradation of ΙκΒα, and nuclear translocation of NF-κB. Hence, we describe a new anti-inflammatory activity and mechanism of stereocalpin A, owing to the negative regulation of TNF-α-induced adhesion molecule and MCP-1 expression, monocyte adhesion and ROS production in vascular smooth muscle cells. These results suggest that stereocalpin A has the potential to exert a protective effect by modulating inflammation within the atherosclerotic lesion.
International immunopharmacology 12/2011; 12(2):315-25. · 2.21 Impact Factor
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ABSTRACT: Ramalin (γ-glutamyl-N'-(2-hydroxyphenyl)hydrazide), a novel compound, was isolated from the methanol-water extract of the Antarctic lichen Ramalina terebrata by several chromatographic methods. The molecular structure of ramalin was determined by spectroscopic analysis. The experimental data showed that ramalin was five times more potent than commercial butylated hydroxyanisole (BHA) in scavenging 1-diphenyl-2-picryl-hydazil (DPPH) free radicals, 27 times more potent in scavenging 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid free radicals (ABTS(+)) than the vitamin E analogue, trolox, and 2.5 times more potent than BHT in reducing Fe(3+) to Fe(2+) ions. Similarly, ramalin was 1.2 times more potent than ascorbic acid in scavenging superoxide radicals and 1.25 times more potent than commercial kojic acid in inhibiting tyrosinase enzyme activity, which ultimately leads to whitening of skin cells. Ramalin showed no or very little cytotoxicity in human keratinocyte and fibroblast cells at its antioxidant concentration. Furthermore, ramalin was assessed to determine its antioxidant activity in vivo. One microgram per milliliter ramalin significantly reduced the released nitric oxide (NO) and 0.125 μg/ml ramalin reduced the produced hydrogen peroxide (H(2)O(2)) in LPS (lipopolysaccharide)-stimulated murine macrophage Raw264.7 cells. Considering all the data together, ramalin can be a strong therapeutic candidate for controlling oxidative stress in cells.
Phytomedicine: international journal of phytotherapy and phytopharmacology 07/2011; 18(14):1285-90. · 2.17 Impact Factor
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ABSTRACT: A Gram-negative, non-motile, catalase- and oxidase- positive, strictly aerobic, and short rod-shaped bacterium that was designated strain KOPRI 25157(T) was isolated from coastal seawater sample in Antarctica. The temperature and pH ranges for growth on R2A agar were 10-20°C, and 5.0-10.0, respectively. Phylogenetic analyses of the 16S rRNA gene sequence of strain KOPRI 25157(T) showed it to belong to the family Oxalobacteraceae of the class Betaproteobacteria, and it formed a distinct clade from other recognized members of the family. DNA G + C content was 65.9 mol%. Major ubiquinone was Q-8. Predominant cellular fatty acids were C(16:1) ω7c/15 iso 2OH (56.4%) and C(16:1) (30.5%). Major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, and unknown lipid. On the basis of these data, it is proposed that strain KOPRI 25157(T) is the representative of a novel genus, for which the name Actimicrobium gen. nov. is proposed in the family Oxalobacteraceae. The type strain for Actimicrobium antarcticum sp. nov. is KOPRI 25157(T) (=JCM 16673(T)=KCTC 23040(T)).
Current Microbiology 06/2011; 63(2):213-7. · 1.82 Impact Factor
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ABSTRACT: The anthropogenic effect on the microbial communities in alpine glacier cryoconites was investigated by cultivation and physiological characterization of bacteria from six cryoconite samples taken at sites with different amounts of human impact. Two hundred and forty seven bacterial isolates were included in Actinobacteria (9%, particularly Arthrobacter), Bacteroidetes (14%, particularly Olleya), Firmicutes (0.8%), Alphaproteobacteria (2%), Betaproteobacteria (16%, particularly Janthinobacterium), and Gammaproteobacteria (59%, particularly Pseudomonas). Among them, isolates of Arthrobacter were detected only in samples from sites with no human impact, while isolates affiliated with Enterobacteriaceae were detected only in samples from sites with strong human impact. Bacterial isolates included in Actinobacteria and Bacteroidetes were frequently isolated from pristine sites and showed low maximum growth temperature and enzyme secretion. Bacterial isolates included in Gammaproteobacteria were more frequently isolated from sites with stronger human impact and showed high maximum growth temperature and enzyme secretion. Ecotypic differences were not evident among isolates of Janthinobacterium lividum, Pseudomonas fluorescens, and Pseudomonas veronii, which were frequently isolated from sites with different degrees of anthropogenic effect.
The Journal of Microbiology 06/2011; 49(3):355-62. · 1.10 Impact Factor
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ABSTRACT: Protein tyrosine phosphatase 1B (PTP1B) is an attractive therapeutic target for diabetes, playing a major role in negative regulation of the insulin signaling pathway. Bioassay-guided investigations of an MeOH extract of the Antarctic lichen, Lecidella carpathica, afforded three PTP1B inhibitory metabolites: hopane-6α,22-diol (1), brialmontin 1 (2), and atraric acid (3), along with two aromatic metabolites (4 and 5) previously isolated from a different Antarctic lichen species. Their structures were determined by analysis of NMR and MS data. Compounds 1–3 inhibited PTP1B activity in a dose-dependent manner with IC50 values of 3.7, 14.0 and 51.5 μM, respectively, and kinetic analyses of PTP1B inhibition by compounds 1 and 2 suggested that these compounds inhibit PTP1B activity in a competitive manner. In addition, 6,22-hopanediol (1) displayed some selectivity toward PTP1B over other protein tyrosine phosphatases, such as TCPTP (IC50 = 8.4 μM), SHP-2 (IC50 > 68 μM), LAR (IC50 > 68 μM), and CD45 (IC50 > 68 μM).
Mycology. 03/2011; 2(1):18-23.
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ABSTRACT: Exposure to low temperatures induces the biosynthesis of specific sets of proteins, including cold shock proteins (Csps). Since many of the specific functions of pychrophilic Csps are unknown, the roles of Csps from an Arctic bacterium, Polaribacter irgensii KOPRI 22228, were examined. The genes encoding CspA and CspC of P. irgensii were cloned in this study. Sequence analysis showed that these proteins have cold shock domains containing two RNA-binding motifs, RNP1 and RNP2. Both proteins bound oligo(dT)-cellulose resins, suggesting single-stranded nucleic acid-binding activity. When the P. irgensii Csps were overexpressed in Escherichia coli, the cold-resistance of the host was increased by more than five-fold. The P. irgensii Csps also rescued a cold-sensitive E. coli csp-quadruple deletion strain, BX04, at low temperatures. These results suggest that Csps from P. irgensii play a role in survival in polar environments.
The Journal of Microbiology 12/2010; 48(6):798-802. · 1.10 Impact Factor
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ABSTRACT: In the present study, cultivation conditions and medium components were optimized using statistical design and analysis to enhance the production of Chi21702, a cold-active extracellular chitinase from the Antarctic bacterium Sanguibacter antarcticus KOPRI 21702. Identification of significant carbon sources and other key elements was performed using a statistical design technique. Chitin and glycerol were selected as main carbon sources, and the ratio of complex nitrogen sources to carbon sources was determined to be 0.5. Among 15 mineral components included in basal medium, NaCl, Fe(C₆H₅O₇), and MgCl₂ were found to have the most influence on Chi21702 production. The optimal parameters of temperature, initial pH, and dissolved oxygen level were found to be 25°C, 6.5, and above 30% of air saturation, respectively. The maximum Chi21702 activity obtained under the optimized conditions was 90 U/L. Through statistical optimization methods, a 7.5-fold increase in Chi21702 production was achieved over unoptimized conditions. Chi21702 showed relatively high activity, even at low temperatures close to 0°C. The information obtained in the present study could be applied to the production of cold-active endochitinase on a large scale, suitable for a process at low temperature in industry.
Applied Microbiology and Biotechnology 10/2010; 89(3):613-21. · 3.42 Impact Factor
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ABSTRACT: Quantitative real time PCR is the most sensitive and widely used method for the analysis of gene expression. The choice of one or several reference genes is very important for a normalization process, which should not fluctuate under stress conditions, to reduce error rate and bias during experimental procedure. In the present study, the expression stability of nine reference genes (two actins, two tubulins, two elongation factor 1α, two ubiquitins, and cyclophilin) during abiotic stresses such as cold, salt, and PEG treatments, was evaluated on Deschampsia antarctica plants using geNorm software. Results from various experimental conditions indicated that cyclophilin and elongation factor 1α were the most stable genes in the leaf and the root, respectively. The expression of the other reference genes varied under stress. The relative quantification of the TACR7 gene varied according to the kind and the number of reference genes used, suggesting the importance of considering the implications of a combination of reference genes under different stress conditions and in different tissues.
Antarctic Science 09/2010; 22(05):477 - 484. · 1.56 Impact Factor
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ABSTRACT: A new approach for enrichment culture was applied to obtain cold-active protease-producing bacteria for marine and terrestrial samples from Svalbard, Norway. The method was developed for the enrichment of bacteria by long-term incubation at low temperatures in semi-solid agar medium containing meat pieces as the main source of carbon and energy. ZoBell and 0.1x nutrient broth were added for marine and terrestrial microorganisms, respectively, to supply basal elements for growth. One to three types of colonies were observed from each enrichment culture, indicating that specific bacterial species were enriched during the experimental conditions. Among 89 bacterial isolates, protease activity was observed from 48 isolates in the screening media containing skim milk. Good growth was observed at 4 degrees C and 10 degrees C while none of the isolates could grow at 37 degrees C. At low temperatures, enzyme activity was equal to or higher than activity at higher temperatures. Bacterial isolates were included in the genera Pseudoalteromonas (33 isolates), Arthrobacter (24 isolates), Pseudomonas (16 isolates), Psychrobacter (6 isolates), Sphingobacterium (6 isolates), Flavobacterium (2 isolates), Sporosarcina (1 isolate), and Stenotrophomonas (1 isolate). Protease activity was observed from Pseudoalteromonas (33 isolates), Pseudomonas (10 isolates), Arthrobacter (4 isolates), and Flavobacterium (1 isolate).
The Journal of Microbiology 08/2010; 48(4):426-32. · 1.10 Impact Factor
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ABSTRACT: An endochitinase was previously purified and the gene was cloned from the psychrophilic Antarctic bacterium, Sanguibacter antarcticus (KCTC 13143). In the present study, recombinant endochitinase, rChi21702, was expressed using a yeast expression system (Pichia pastoris) and codon optimization. The expressed rChi21702 was purified by Phenyl-Sepharose column chromatography. Optimal expression yielded 1-mg purified enzyme from 1-L bioreactor culture. When p-NP-(GlcNAc)(2) was used as a substrate, the specific activity of the enzyme was determined to be 20U/mg. In vitro assays and thin-layer chromatography demonstrated that the recombinant enzyme has endochitinase activity that produces diacetyl-chitobiose as a dominant end product when chitooligomers, colloidal chitin, and the chromogenic p-NP-(GlcNAc)(2) are used as substrates. Optimal activity for rChi21702 was observed at 37 degrees C and a pH of 7.6. Interestingly, rChi21702 exhibited 63% of optimal activity at 10 degrees C and 44% activity at 0 degrees C. Taken together, the results indicate that rChi21702 has psychrotolerant endochitinase activity even after recombinant expression in yeast cells.
Protein Expression and Purification 05/2010; 71(1):108-14. · 1.59 Impact Factor
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ABSTRACT: Type I collagen is the major structural protein in dermis and its presence is used to monitor skin cell proliferation and aging. Recently, novel usimine compounds have been found in the Antarctic lichen Ramalina terebrata. In the present study, usimine-C induced cell proliferation of human dermal fibroblast, CCD-986SK, up to 1.6-fold after treating with 90 microg/ml for 48 h. Type I procollagen synthesis was significantly increased 1.3-fold, 3-fold, and 5-fold after treating with 0.14, 0.72, and 3.6 microg usimine-C/ml for 24 h, respectively, whereas no significant increase in type I procollagen was observed after treating with usimine-A or -B. Usimines are usnic acid derivatives. Considering that the difference among the derivatives is a side chain, the proliferation activity may be related to this side chain, triggering an internal signal for type I procollagen expression. Further studies still remain to clarify the signaling pathways for the type I procollagen induction, which is activated by usimine-C.
Biotechnology Letters 04/2010; 32(4):471-5. · 1.68 Impact Factor
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ABSTRACT: A polar bacterium was isolated from Arctic sea sediments and identified as Psychromonas artica, based on 16S rDNA sequence. Psychromonas artica KOPRI 22215 has an optimal growth temperature of 10 degrees C and a maximum growth temperature of 25 degrees C, suggesting this bacterium is a psychrophile. Cold shock proteins (Csps) are induced upon temperature downshift by more than 10 degrees C. Functional studies have researched mostly Csps of a mesophilic bacterium Escherichia coli, but not on those of psychrophilic bacteria. In an effort to understand the molecular mechanisms of psychrophilic bacteria that allow it withstand freezing environments, we cloned a gene encoding a cold shock protein from P. artica KOPRI 22215 (CspA(Pa)) using the conserved sequences in csp genes. The 204 bp-long ORF encoded a protein of 68 amino acids, sharing 56% homology to previously reported E. coli CspA protein. When CspA(Pa) was overexpressed in E. coli, it caused cell growth-retardation and morphological elongation. Interestingly, overexpression of CspA(Pa) drastically increased the host's cold-resistance by more than ten times, suggesting the protein aids survival in polar environments.
The Protein Journal 02/2010; 29(2):136-42. · 1.04 Impact Factor
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ABSTRACT: The selective inhibition of PTP1B has been widely recognized as a potential drug target for the treatment of type 2 diabetes and obesity. In the course of screening for PTP1B inhibitory natural products, the MeOH extract of the dried sample of the Antarctic lichen Umbilicaria antarctica was found to exhibit significant inhibitory effect, and the bioassay-guided fractionation and purification afforded three related lichen metabolites 1-3. Compounds 1-3 were identified as gyrophoric acid (1), lecanoric acid (2), and methyl orsellinate (3) mainly by analysis of NMR and MS data. These compounds inhibited PTP1B activity with 50% inhibitory concentration values of 3.6 +/- 0.04 microM, 31 +/- 2.7 microM, and 277 +/- 8.6 microM, respectively. Furthermore, the kinetic analysis of PTP1B inhibition by compound 1 suggested that the compound inhibited PTP1B activity in a non-competitive manner.
Journal of Enzyme Inhibition and Medicinal Chemistry 08/2009; 24(5):1133-7. · 1.62 Impact Factor
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ABSTRACT: Seven phenolic lichen metabolites (1-7) have been isolated from a methanol extract of the Antarctic lichen Stereocaulon alpinum by various chromatographic methods. The structures of these compounds were determined mainly by analysis of NMR spectroscopic data. A depsidone-type compound, lobaric acid (1) and two pseudodepsidone-type compounds, 2 and 3, exhibited potent inhibitory activity against protein tyrosine phosphatase 1B (PTP1B) with IC(50) values of 0.87microM, 6.86microM, and 2.48microM, respectively. Kinetic analyses of PTP1B inhibition by compounds 1 and 2 suggested that these compounds inhibited PTP1B activity in a non-competitive manner.
Bioorganic & medicinal chemistry letters 04/2009; 19(10):2801-3. · 2.65 Impact Factor
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ABSTRACT: Prodigiosin is a natural red pigment with algicidal activity against Cochlodinium polykrikoides, a major harmful redtide microalga. To increase the yield of prodigiosin production by Hahella chejuensis KCTC 2396, significant medium components were determined using a two-level Plackett- Burman statistical design technique. Among 12 components included in basal medium, NaHCO3, Na2SiO3, NH4NO3, Na2SO4, and CaCl2 were determined to be important for prodigiosin production. The medium formulation was finally optimized using a Box-Behnken design as follows: 1% sucrose; 0.4% peptone; 0.1% yeast extract; and (g/l): NaCl, 20.0; Na2SO4, 9.0; CaCl2, 1.71; KCl, 0.4; and (mg/l): H3BO3, 10.0; KBr, 50.0; NaF, 2.0; NaHCO3, 45.0; Na2SiO3, 4.5; NH4NO3, 4.5. The predicted maximum yield of prodigiosin in the optimized medium was 1.198 g/l by the Box-Behnken design, whereas the practical production was 1.495 g/l, which was three times higher than the basal medium (0.492 g/l).
Journal of Microbiology and Biotechnology 01/2009; 18(12):1903-7. · 1.38 Impact Factor
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ABSTRACT: Harmful algal blooms (HABs), commonly called red tides, are caused by some toxic phytoplanktons, and have made massive economic losses as well as marine environmental disturbances. As an effective and environment-friendly strategy to control HAB outbreaks, biological methods using marine bacteria capable of killing the harmful algae or algicidal extracellular compounds from them have been given attention. A new member of the gamma-Proteobacteria, Hahella chejuensis KCTC 2396, was originally isolated from the Korean seashore for its ability to secrete industrially useful polysaccharides, and was characterized to produce a red pigment. This pigment later was identified as an alkaloid compound, prodigiosin. During the past several decades, prodigiosin has been extensively studied for its medical potential as immunosuppressants and antitumor agents, owing to its antibiotic and cytotoxic activities. The lytic activity of this marvelous molecule against Cochlodinium polykrikoides cells at very low concentrations (1 ppb) was serendipitously detected, making H. chejuensis a strong candidate among the biological agents for HAB control. This review provides a brief overview of algicidal marine bacteria and their products, and describes in detail the algicidal characteristics, biosynthetic process, and genetic regulation of prodigiosin as a model among the compounds active against red-tide organisms from the biochemical and genetic viewpoints.
Journal of Microbiology and Biotechnology 11/2008; 18(10):1621-9. · 1.38 Impact Factor
