• Journal of Microbiology and Biotechnology
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• v.16 no.12
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• pp.1912-1918
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• 2006

Marine bacterium Hahella chejuensis KCTC 2396 simultaneously produced red antibiotic prodigiosin and undecylprodiginine. A complete set of the prodigiosin biosynthetic gene cluster has been cloned, sequenced, and successfully expressed in a heterologous host. Sequence analysis of the gene cluster revealed 14 ORFs showing high similarity to pig and red genes from Serratia spp. and Streptomyces coelicolor A3(2), respectively, and the gene organization was almost: similar to that of pig genes. These genes were named hap for Hahella prodigiosin, and determined to be transcribed as a single operon, by RT-PCR experiment. Based on the hap gene mutagenesis experiments and comparative analysis with pig and red genes, we propose a prodigiosin-biosynthetic pathway in KCTC 2396.

• Journal of Microbiology and Biotechnology
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• v.17 no.6
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• pp.979-984
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• 2007

The physicochemical properties of the exopolysaccharide (EPS) produced by marine bacterium Zoogloea sp. KCCM10036 were investigated. Two types of isolated EPSs were shown to have average relative molecular masses $(M_r)\;of\;4.07{\times}10^6$ of CBP (cell-bound polysaccharide) and $3.43{\times}10^6$ of WSP (water-soluble polysaccharide), respectively. When the CBP was utilized as an emulsifier, it stabilized the emulsifier, for up to 148 h. Compared with other commercially available hydrocolloids such as xanthan gum, the Tween series, and Triton, the CBP showed much better emulsifying capability on a water-in-oil system. Phase separation occurred in the Tween series after 24 h, whereas the emulsion was better stabilized by the CBP. The CBP thus has potential as an emulsifying agent in commercial emulsions. The flocculating activity was also greatest at 0.01% (w/v) and decreased at higher concentrations than the optimized concentration of the WSP and CBP. The results also showed that both types of expolysaccharides from Zoogloea sp. had excellent flocculating activity.

• Journal of Microbiology and Biotechnology
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• v.8 no.3
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• pp.245-250
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• 1998

A gene encoding an extracellular collagenase from the marine bacterium Vibrio vulnificus CYK279H was cloned into E. coli JM83 using the multicopy plasmid vector pUC19. The cloned strain of recombinant E. coli showing collagenase activity had an insert fragment of 3.5 kb and was named E. coli JM83/pKCL 279H. The cloned strain produced two different collagenase during cultivation. These enzymes, named collagenase-I and -II, were purified from the culture supernatant. SDS-PAGE indicated that collagenase-I had a molecular weight of 41 kDa and collagenase-II had a weight of 37 kDa. The N-terminal amino acid sequence of collagenase-I from the cloned strain, E. coli JM83/pKCL279H was determined and was not found to be similar to any other known collagenases. The optimum pH and temperature of the purified collagenase-I were 7.8 and $37^{\circ}C$, respectively.

• The Plant Pathology Journal
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• v.39 no.6
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• pp.584-591
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• 2023

Active plant immune response involving programmed cell death called the hypersensitive response (HR) is elicited by microbial effectors delivered through the type III secretion system (T3SS). The marine bacterium Hahella chejuensis contains two T3SSs that are similar to those of animal pathogens, but it was able to elicit HR-like cell death in the land plant Nicotiana benthamiana. The cell death was comparable with the transcriptional patterns of H. chejuensis T3SS-1 genes, was mediated by SGT1, a general regulator of plant resistance, and was suppressed by AvrPto1, a type III-secreted effector of a plant pathogen that inhibits HR. Thus, type III-secreted effectors of a marine bacterium are capable of inducing the nonhost HR in a land plant it has never encountered before. This suggests that plants may have evolved to cope with a potential threat posed by alien pathogen effectors. Our work documents an exceptional case of nonhost HR and provides an expanded perspective for studying plant nonhost resistance.

• Journal of fish pathology
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• v.6 no.2
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• pp.197-204
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• 1993

Flounder culture has been developed mainly in the western parts of japan, and, to date, following six bacterial diseases have been reported. Bacterial white enteritis occurs in 16 to 30-day-old flounder larvae and often causes mass mortality in seed production. Bacterium named Vibrio sp. INFL invades and multiplies in the mucosae of posterier part of intestine, and causes desquamative enteritis. Gliding bacterial disease occurs mostly in juvenile stage and in spring to summer. Diseased signs are partial discoloration and erosion of skin and fins. Histologically, epidermis are removed, and the causative bacterium, Flexibacter maritimus, multiplies on the surface of demis and invades into the muscular tissue. Vibriosis caused by Vibrio anguillarum and related organisum is one of the well-known diseases among marine fish. Outbreaks of the disease in flounder culture are relatively few, but mass mortalities in fingerlings due to the disease were reported. An outbreak of nocardiosis in the autumn of 1984 has been reported, but since then the disease scarcely occurred. The disease is characterized by formation of abscesses under the skin and white nodes in the gill, heart, spleen and kidney. Streptococcicosis occurs frequently in recent years. Beta-hemolytic streptococcus is the causative bacterium, which possesses the same biochemical and serological characteristics as $\beta$-streptococci isolated from some marine and freshwater fish, and is seemed to related to Streptococcus iniae. Edwardsiellosis is the disease that causes most damage in flounder culture in Japan. Characteristic symptoms are swelling of abdomen and intestinal protrusion from the anus due to accumulation of ascites. Edwardsiella tarda, a well-known pathogen of freshwater fish, is the causative bacterium of the disease.

• Fisheries and Aquatic Sciences
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• v.11 no.2
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• pp.76-81
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• 2008

We isolated 1,916 strains of bacteria from gut and feces of abalone. The most active agarolytic bacterium, DAG-130, was identified from the gut of the abalone Haliotis gigantea. Of the bacteria harbored by both H. discus hannai and H. gigantea, 59% were agarolytic. There was no significant difference in the number of agarolytic bacteria isolated from abalone fed on the seaweeds Gelidium amansii, Laminaria japonica, or Undaria pinnatifida. Of the agarolytic bacteria, 72% were isolated from the guts of all sources tested while 43% came from the feces. The strain DAG-130 showed 100% identity with the bacterium Vibrio cyclotrophicus based on phylogenetic analysis of l6S rDNA. The bacterium produced monomers and oligomers from the agar substrate.

• Journal of Life Science
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• v.26 no.2
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• pp.198-203
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• 2016

This study aimed to isolate a novel agarase-producing marine bacterium and characterize its agarase, as agarases are known to produce biofunctional agarooligosaccharides or neo-agarooligosaccharides. A novel agar-degrading bacterium, SH-2, was isolated from the seawater of Namhae in Gyeongnam Province, Korea, and cultured in Marine agar 2216 medium. The 16S rRNA gene sequence represented 99% identity with that of the members of the Marinomonas genus; hence, the isolated bacterium was named Marinomonas sp. SH-2. The crude agarase was prepared from a culture medium of Marinomonas. sp SH-2, and exhibited maximum agarase activity at 170.2 units/l. The optimum conditions were pH 6.0 and 30℃ in 20 mM Tris-HCl buffer. The agarase activity of the bacterium was highly elevated from 20℃(42% relative activity) to 30℃(100%), and 82% activity was shown at 40℃. Its relative activities were less than 40% at over 40℃ after a 0.5 hr exposure. Relative activity was 100% at pH 6.0, while it was 72% and 48% at pH 5.0 and pH 7.0, respectively. The enzyme from Marinomonas sp. SH-2 degraded agarose to neoagarohexaose and neoagarotetraose, indicating that the enzyme is β-agarase. Thus, Marinomonas sp. SH-2 and its enzyme could be practical for applications in food, cosmetic, and medical research.

• Korean Journal of Microbiology
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• v.41 no.2
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• pp.112-116
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• 2005

Moderately halophilic bacterium, Kordia algicida gen. nov., sp. novo was isolated from seawater of Masan Bay, Korea, during algal blooming caused by Skeletonema costatum. This bacterium was grown on the ZoBell 2216e medium supplied aged seawater, but not grown the medium supplied $3\%$ NaCl. This bacterium showed absolute requirements for mono and divalent cations such as $Na^+,\;Mg^{2+}\;and\;Ca^{2+}$, since no growth was observed in the medium, which is not supplemented with one of $Na^+,\;Mg^{2+}\;and\;Ca^{2+}$ ions. In kinetic studies for three kinds of cation, Km values of $Na^+,\;Ca^{2+}\;and\;Mg^{2+}$ were determined to 0.202 M, 0.089 mM, and 0.189 mM, respectively. Also, $V_{max}({\mu}max)$ was 0.442 h, 0.411 hand 0.316 h. The bacterial cells were quickly lysed in the condition limited by the cations. This result should be suggested that Kordia algicida originated from marine.

• Microbiology and Biotechnology Letters
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• v.44 no.2
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• pp.156-162
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• 2016

In this study, we isolated a new agar-degrading marine bacterium and characterized its agarase. An agardegrading marine bacterium SH-1 was isolated from seawater, collected from the seashore of Namhae in Gyeongnam province, Korea, and cultured in marine agar 2216 media. It was identified as Maribacter. sp. SH-1 by phylogenetic analyses, based on 16S rRNA gene sequence. The extracellular agarase was extracted from culture media of Maribacter sp. SH-1 and characterized. Its relative activities were 56, 62, 94, 100, and 8% at 20, 30, 40, 50, and 60℃, respectively, whereas 15, 100, 60, and 21% relative activities were observed at pH 5, 6, 7, and 8, respectively. Its extracellular agarase exhibited maximum activity (231 units/l) at pH 6.0 and 50℃, in 20 mM Tris-HCl buffer. Therefore, this agarase would be applicable as it showed the maximum activity at the temperature at which the agar is in a sol state. Furthermore, the agarase activities remained over 90% at 20, 30, and 40℃ after 0.5 h exposure at these temperatures. Thin layer chromatography analysis suggested that Maribacter sp. SH-1 produces extracellular β-agarase, as it hydrolyzes agarose to produce neoagarooligosaccharides, such as neoagarohexaose (34.8%), neoagarotetraose (52.2%), and neoagarobiose (13.0%). Maribacter sp. SH-1 and its β-agarase would be useful for the production of neoagarooligosaccharides, which shows functional properties, like skin moisturizing, skin whitening, inhibition of bacterial growth, and delay in starch degradation.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.343-346
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• 2005

The isolated strain, SC2-1 was Gram-positive, catalase positive, facultatively anaerobic, oxidase negative, motile and small rods. The strain utilized sucrose, dextrose, fructose, mannitol and maltose as a sole carbon and energy source and sodium chloride required for the bacteria growth. The radical scavenging activity of the culture supernatants was determined by DPPH (1,1-diphenyl-2-picrylhydrazyl) method. This bacterium was identified based on cellular fatty acids analysis and 16S rDNA sequencing then named Exiguobacterium sp. SC2-1. The optimum culture conditions for production of antioxidant were $25^{\circ}C,$ pH 7.8 and NaCl concentration were 4%. The modified optimal medium compositions were maltose 2.5% (w/v), yeast extract 1.5% (w/v) and $KH_2PO_4$ 0.05% (w/v). Free radical scavenging activity of under optimal culture conditions were 93%.