• Microbiology and Biotechnology Letters
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• v.45 no.2
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• pp.168-177
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• 2017

Strain A28-5, which can degrade xylan and agar in solid medium, was isolated from a coastal seawater sample collected from Jeju Island, South Korea. This strain was found to be a gram-negative, $Na^+$-requiring bacterial strain with a polar flagellum for motility. Additionally, the strain was tolerant to antibiotics such as ampicillin and thiostrepton. The G+C content of the genome was 43.96% and menaquinone-7 was found to be the predominant quinone. Major fatty acids constituting the cell wall of the strain were $C_{16:1}$ ${\omega}7c/iso-C_{15:0}$ 2-OH (23.32%), $C_{16:0}$ (21.83%), and $C_{18:1}$ ${\omega}7c$ (17.98%). The 16S rRNA gene sequence of the strain showed the highest similarity (98.94%) to that of Catenovulum agarivorans YM01, which was demonstrated by constructing a neighbor-joining phylogenetic tree. A28-5 was identified as a novel species of the genus Catenovulum via DNA-DNA hybridization with Catenovulum agarivorans YM01, and thus was named as Catenovulum jejuensis A28-5. The formation of tetramers and hexamers of xylooligosaccharides and (neo)agarooligosaccharides, respectively, were confirmed by thin-layer chromatography analysis using an enzyme reaction solution containing xylan or agarose with two crude enzymes prepared from the liquid culture of the strain.

• BMB Reports
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• v.50 no.5
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• pp.263-268
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• 2017

${\beta}$-Agarase cleaves the ${\beta}$-1,4 linkages of agar to produce neoagarooligosaccharides (NAO), which are associated with various physiological functions. However, the immunological functions of NAO are still unclear. In this study, we demonstrated that ${\beta}$-agarase DagA-produced neoagarohexaose (DP6), an NAO product, promoted the maturation of dendritic cells (DCs) by Toll-like receptor 4 (TLR4). DP6 directly and indirectly enhanced the activation of natural killer (NK) cells in a TLR4-dependent manner in vitro and in vivo. Finally, the antitumor activity of DP6 against B16F1 melanoma cells was inhibited in NK cell-depletion systems by using NK-cell depleting antibodies in vivo. Collectively, the results indicated that DP6 augments antitumor immunity against B16F1 melanoma cells via the activation of DC-mediated NK cells in a TLR4-dependent manner. Thus, DP6 is a potential candidate adjuvant that acts as an immune cell modulator for the treatment of melanoma.

• Korean Journal of Microbiology
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• v.54 no.4
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• pp.463-464
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• 2018

Tamlana sp. UJ94 isolated from seawater can degrade alginate. To identify the genomic basis of this activity, the genome was sequenced. The genome was composed of 4,116,543 bp, 3,609 coding sequences, and 35.2 mol% G + C content. A BLASTp search predicted the presence of 9 alginate lyases as well as 6 agarases, 5 amylases, 4 carrageenases, 1 cellulase, 4 pectate lyases, and 7 xylanases, indicating its ability to degrade diverse polysaccharides. The genome of strain UJ94 is a source of polysaccharide-degrading enzymes for bioconversion processes.

• The Korean Journal of Food And Nutrition
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• v.35 no.1
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• pp.43-50
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• 2022

Agar, a heterogeneous polymer of galactose, is the main component of the cell wall of marine red algae. It is well established as a safe, non-digestible carbohydrate in oriental countries. Neoagarooligosaccharides (NAOs) prepared by hydrolyzing agar by microbial β-agarase have been reported to show safety. However, their immunological effects have not been reported yet. Thus, the objective of this study was to investigate immune enhancing effects of neoagarooligosaccharides (NAOs) from marine red algae Gelidium elegans in mice by performing ex vivo experiments. Six-week-old mice were fed ad libitum. NAOs were orally administrated at three different concentrations (100, 500, and 2,500 mg/kg B.W./day) twice a week for four weeks. The group fed with NAOs at 2,500 mg/kg showed the highest proliferation of splenocytes and production levels of cytokines (IL-1β, IL-6, TNF-α) in the ex vivo experiment. In conclusion, NAOs can enhance immune function, increase proliferation of splenocytes, and increase cytokine production by activating macrophages in mice.

• KSBB Journal
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• v.16 no.4
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• pp.398-402
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• 2001

Enzymatic hydrolysis of agar was carried out continuously to produce agarooligosaccharides by immobilized agarase in Packed-Bed Reactor. The reactor was constructed using a acryl tube with an internal diameter of 10 mm and a useful height of 140 mm. The Packed-Bed Reactor was 11 mL reactor volume as its length : diameter ratio was 14 : 1. The operation condition of reaction was performed with an 1 g/L agar concentration at 40$^{\circ}C$, 10 mM MOPS buffer(pH 7.0) and with the flow rate 3 mL∼48 mL/h at a dilution rate of 1.09∼5.45 h$\^$-1/. The hydrolysis products was identified DP6, DP4 and DP2 by HPLC. The conversion rate of agar was about 80% and amount of total agarooligosaccharide was 0.88 mg/mL at Packed-Bed Reactor.

• Korean Journal of Microbiology
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• v.52 no.3
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• pp.344-351
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• 2016

A marine bacterium, designated as strain 50C-3, was isolated from a seawater sample collected from the East Sea of South Korea. The strain is a Gram-negative, aerobic, yellow colored polar-flagellated bacterium that grows at $20-50^{\circ}C$ and pH 5.5-8.5. Optimal growth occurred at $40-50^{\circ}C$, at pH 6.5-7.5, and in the presence of 2% (w/v) NaCl. Based on 16S rRNA gene sequence similarity, the isolate was considered to represent a member of the genus Ruegeria. The result of this analysis showed that strain 50C-3 shared 99.4% and 96.98% sequence similarity with Ruegeria intermedia CC-GIMAT-$2^T$ and Ruegeria lacuscaerulensis ITI-$1157^T$, respectively. Furthermore, strain 50C-3 showed clear differences from related strains in terms of several characteristics such as motility, carbon utilization, enzyme production, etc. The DNA G+C content was 66.7 mol%. Chemotaxonomic analysis indicated ubiquinone-10 (Q-10) as the predominant respiratory quinone. Based on phenotypic, chemotaxonomic, and phylogenetic characteristics, the isolate represents a novel variant of the Ruegeria intermedia CC-GIMAT-$2^T$, for which we named Ruegeria sp. 50C-3 (KCTC23890=DSM25519). Strain 50C-3 did not produce cellulase and agarase, but produced alkaline phosphatase, ${\alpha}$-galactosidase, and ${\beta}$-galactosidase. The three enzymes showed stable activities even at $50^{\circ}C$ and thus regarded as thermostable enzymes. Especially, the ${\beta}$-galactosidase activity enhanced by 1.9 times at $50^{\circ}C$ than that at $37^{\circ}C$, which may be very useful for industrial application.

• Journal of Life Science
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• v.22 no.2
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• pp.259-265
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• 2012

A bacterial strain, CK214, exhibiting high motility on an LB agar (1.5%, w/v) surface was isolated from the environment. The formation of unusual agar shrinking around colonies on agar plates was observed. The strain grew on minimal media containing pure agar as a sole carbon source. The cell-free culture supernatant of CK214 generated a reduced form of sugar in the in vitro reaction with the use of pure agar as a substrate, suggesting the secretion of an agar-degrading enzyme. The CK214 strain showed swarming motility on the solid media containing a wide range of concentrations of agar (0.5, 1.0, 1.5, 2.0% w/v). Various tests, including Gram staining, API analysis, and phylogenetic analysis based on 16S rDNA sequences identified that the CK214 strain was a G(+) rod-shaped bacterium grouped in genus Paenibacillus. Electron microscopic analysis demonstrated that the P. CK214 strain is peritrichously flagellated. Through transposon random mutagenesis, several agar-degrading activity defective mutants (ADMs) were generated. These mutants will be used in the future experimentation for the study of the correlation between agar-degrading activity and motility.

• Journal of Life Science
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• v.22 no.6
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• pp.751-759
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• 2012

Microbulbifer sp. was used to acquire the degrading products from Ecklonia cava (DPEC) and the products were investigated to determine the physiological activities. Firstly, 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity and superoxide dismutase (SOD) assay were about 84.1% and 89.6% at 2.5 mg/ml, respectively. In addition, nitrite scavenging ability was shown to be 56.3% at 0.5 mg/ml on pH 1.2. ${\alpha}$-Glucosidase inhibitory activity was increased in a dose-dependent manner and was about 58.7% at 2.5 mg/ml. To determine the influence of DPEC on alcohol metabolism, the generating activity of reduced-nicotinamide adenine dinucleotide (NADH) by alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) were measured. Facilitating rates of ADH and ALDH activities by DPEC were 123.3% and 215.2% at 2.5 mg/ml, respectively. For analyses of anti-wrinkling and whitening effects, its elastase and tyrosinase inhibitory activities were measured and were about 73.1% and 42.2% at 2.5 mg/ml, respectively. These results indicated that DPEC has valuable biological attributes owing to its antioxidant, nitrite scavenging, and alcohol metabolizing activities and ${\alpha}$-glucosidase, elastase, and tyrosinase inhibitory activities.

• Journal of Microbiology and Biotechnology
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• v.23 no.11
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• pp.1509-1518
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• 2013

An agar-degrading bacterium, designated as strain $G7^T$, was isolated from a coastal seawater sample from Gaya Island (Gayado in Korean), Republic of Korea. The isolated strain $G7^T$ is gram-negative, rod shaped, aerobic, non-motile, and non-pigmented. A similarity search based on its 16S rRNA gene sequence revealed that it shares 95.5%, 90.6%, and 90.0% similarity with the 16S rRNA gene sequences of Catenovulum agarivorans $YM01^T$, Algicola sagamiensis, and Bowmanella pacifica W3-$3A^T$, respectively. Phylogenetic analyses demonstrated that strain $G7^T$ formed a distinct monophyletic clade closely related to species of the family Alteromonadaceae in the Alteromonas-like Gammaproteobacteria. The G+C content of strain $G7^T$ was 41.12 mol%. The DNA-DNA hybridization value between strain $G7^T$ and the phylogenetically closest strain $YM01^T$ was 19.63%. The genomes of $G7^T$ and $YM01^T$ had an average ANIb value of 70.00%. The predominant isoprenoid quinone of this particular strain was ubiquinone-8, whereas that of C. agarivorans $YM01^T$ was menaquinone-7. The major fatty acids of strain $G7^T$ were Iso-$C_{15:0}$ (41.47%), Anteiso-$C_{15:0}$ (22.99%), and $C_{16:1}{\omega}7c/iso-C_{15:0}2-OH$ (8.85%), which were quite different from those of $YM01^T$. Comparison of the phenotypic characteristics related to carbon utilization, enzyme production, and susceptibility to antibiotics also demonstrated that strain $G7^T$ is distinct from C. agarivorans $YM01^T$. Based on its phenotypic, chemotaxonomic, and phylogenetic distinctiveness, strain $G7^T$ was considered a novel genus and species in the Gammaproteobacteria, for which the name Gayadomonas joobiniege gen. nov. sp. nov. (ATCC BAA-2321 = $DSM25250^T=KCTC23721^T$) is proposed.