Acinetobacter plantarum sp. nov. isolated from wheat seedlings plant.

Strain THG-SQM11(T), a Gram-negative, aerobic, non-motile, coccus-shaped bacterium, was isolated from wheat seedlings plant in P. R. China. Strain THG-SQM11(T) was closely related to members of the genus Acinetobacter and showed the highest 16S rRNA sequence similarities with Acinetobacter junii (97.9 %) and Acinetobacter kookii (96.1 %). DNA-DNA hybridization showed 41.3 ± 2.4 % DNA reassociation with A. junii KCTC 12416(T). Chemotaxonomic data revealed that strain THG-SQM11(T) possesses ubiquinone-9 as the predominant respiratory quinone, C18:1 ω9c, summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), and C16:0 as the major fatty acids. The major polar lipids were found to be diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidylcholine. The DNA G+C content was 41.7 mol %. These data, together with phenotypic characterization, suggest that the isolate represents a novel species, for which the name Acinetobacter plantarum sp. nov. is proposed, with THG-SQM11(T) as the type strain (=CCTCC AB 2015123(T) =KCTC 42611(T)).

Antitumoral Activity of (20R)- and (20S)-Ginsenoside Rh2 on Transplanted Hepatocellular Carcinoma in Mice.

Hepatocellular carcinoma is one of the leading causes of malignancy-related death in China. Its therapy in clinics is a big challenge. Ginsenoside Rh2 is one of the most notable cancer-preventing components from red ginseng and it has been reported that ginsenoside Rh2 exhibited potent cytotoxicity against human hepatoma cells. Rh2 exists as two different stereoisomeric forms, (20S)-ginsenoside Rh2 and (20R)-ginsenoside Rh2. Previous reports showed that the Rh2 epimers demonstrated different pharmacological activities and only (20S)-ginsenoside Rh2 showed potent proliferation inhibition on cancer cells in vitro. However, the in vivo anti-hepatoma activity of (20R)-ginsenoside Rh2 and (20S)-ginsenoside Rh2 has not been reported yet. This work assessed and compared the anti-hepatoma activities of (20S)-ginsenoside Rh2 and (20R)-ginsenoside Rh2 using H22 a hepatoma-bearing mouse model in vivo. In addition, hematoxylin and eosin staining, the deoxynucleotidyl transferase dUTP nick-end labeling assay, and the semiquantitative reverse transcriptase polymerase chain reaction method were used to further study the apoptosis of the tumors. The results showed that both (20S)-ginsenoside Rh2 and (20R)-ginsenoside Rh2 suppressed the growth of H22 transplanted tumors in vivo, and the highest inhibition rate could be up to 42.2 and 46.8 %, respectively (p < 0.05). Further, hematoxylin/eosin staining and the deoxynucleotidyl transferase dUTP nick-end labeling assay indicated that both (20R)-ginsenoside Rh2 and (20S)-ginsenoside Rh2 could induce H22 hepatoma tumor cell apoptosis, with apoptosis indexes of 3.87 %, and 3.80 %, respectively (p < 0.05). Moreover, this effect was accompanied by downregulating the level of Bcl-2 mRNA. In conclusion, both (20S)-ginsenoside Rh2 and (20R)-ginsenoside Rh2 can suppress the growth of H22 hepatomas without causing severe side effects, and this effect is associated with the induction of apoptosis.

Sphingomonas flavus sp. nov. isolated from road soil.

A yellow-colored, Gram-negative, strictly aerobic, non-motile, rod-shaped bacterium, designated THG-MM5(T), was isolated from road soil in Yongin-si, Gyeonggi-do, Republic of Korea. Based on 16S rRNA gene sequence, strain THG-MM5(T) was moderately related to Sphingomonas sediminicola KACC 15039(T) (96.1%), Sphingomonas ginsengisoli KACC 16858(T) (96.1%) and Sphingomonas jaspsi KACC 13230(T) (96.0%). Chemotaxonomic data revealed that strain THG-MM5(T) possesses ubiquinone-10 as the only respiratory quinone, sym-homospermidine as the major polyamine and summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), C18:1 ω7c and C16:0 as the major fatty acids. The polar lipid profile included sphingoglycolipid. The DNA G + C content was 60.7 mol%. These data, together with phenotypic characterization, corroborated the affiliation of strain THG-MM5(T) to the genus Sphingomonas. Thus, the isolate represents a novel species, for which the name Sphingomonas flavus sp. nov. is proposed, with THG-MM5(T) as the type strain (=KACC 18277(T) = CCTCC AB 2014320(T)).

Sphingobacterium mucilaginosum sp. nov., isolated from rhizosphere soil of a rose.

A Gram-stain-negative, strictly aerobic, motile, short-rod-shaped bacterium, designated strain THG-SQA8(T), was isolated from rhizosphere soil of rose in PR China. Strain THG-SQA8(T) was closely related to members of the genus Sphingobacterium, showed the highest sequence similarities with Sphingobacterium multivorum KACC 14105(T) (98.0%) and Sphingobacterium ginsenosidimutans KACC 14526(T) (97.4%). DNA-DNA hybridization showed values of 35.2 ± 0.9% and 8.8 ± 0.3% DNA reassociation with S. multivorum KACC 14105(T) and S. ginsenosidimutans KACC 14526(T), respectively. Chemotaxonomic data revealed that strain THG-SQA8(T) possesses menaquinone-7 as the only respiratory quinone, and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), iso-C1 : 0 and C16 : 0 as the major fatty acids. The major polar lipid was phosphatidylethanolamine. The DNA G+C content was 40.7 mol%. These data corroborated the affiliation of strain THG-SQA8(T) to the genus Sphingobacterium. Thus, the isolate represents a novel species, for which the name Sphingobacterium mucilaginosum sp. nov. is proposed, with THG-SQA8(T) as the type strain ( = CCTCC AB 2014317(T) = KCTC 42503(T)).

Chryseobacterium solani sp. nov., isolated from field-grown eggplant rhizosphere soil.

Strain THG-EP9T, a Gram-stain-negative, aerobic, motile, rod-shaped bacterium was isolated from field-grown eggplant (Solanum melongena) rhizosphere soil collected in Pyeongtaek, Gyeonggi-do, Republic of Korea. Based on 16S rRNA gene sequence comparisons, strain THG-EP9T had closest similarity with Chryseobacterium ginsenosidimutans THG 15T (97.3 % 16S rRNA gene sequence similarity), Chryseobacterium soldanellicola PSD1-4T (97.2%), Chryseobacterium zeae JM-1085T (97.2%) and Chryseobacterium indoltheticum LMG 4025T (96.8%). DNA-DNA hybridization showed 5.7% and 9.1% DNA reassociation with Chryseobacterium ginsenosidimutans KACC 14527T and Chryseobacterium soldanellicola KCTC 12382T, respectively. Chemotaxonomic data revealed that strain THG-EP9T possesses menaquinone-6 as the only respiratory quinone and iso-C15 : 0 (29.0%), C16 : 0 (12.5%) and iso-C17 : 0 3-OH (11.9 %) as the major fatty acids. The polar lipid profile consisted of phosphatidylethanolamine, an unidentified aminophospholipid, two unidentified glycolipids, six unidentified aminolipids and two unidentified polar lipids. The DNA G+C content was 35.3 mol%. These data corroborated the affiliation of strain THG-EP9T to the genus Chryseobacterium. Thus, the isolate represents a novel species of this genus, for which the name Chryseobacterium solani sp. nov. is proposed, with THG-EP9T ( = KACC 17652T = JCM 19456T) as the type strain.

Lysobacter terrae sp. nov. isolated from Aglaia odorata rhizosphere soil.

A Gram-stain negative, facultatively anaerobic, non-motile, rod-shaped bacterium, designated strain THG-A13(T), was isolated from Aglaia odorata rhizosphere soil in Gyeonggi-do, Republic of Korea. Based on 16S rRNA gene sequence comparisons, strain THG-A13(T) had close similarity with Lysobacter niabensis GH34-4(T) (98.5 %), Lysobacter oryzae YC6269(T) (97.9 %) and Lysobacter yangpyeongensis GH19-3(T) (97.3 %). Chemotaxonomic data revealed that strain THG-A13(T) possesses ubiquinone-8 (Q8) as the predominant isoprenoid quinone and iso-C15 : 0, iso-C16 : 0 and iso-C17 : 1ω9c as the major fatty acids. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol) and diphosphatidylglycerol. The G+C content was 66.3 mol%. The DNA-DNA relatedness values between strain THG-A13(T) and its closest phylogenetic neighbours were below 18.0 %. These data corroborated the affiliation of strain THG-A13(T) to the genus Lysobacter. These data suggest that the isolate represents a novel species for which the name Lysobacter terrae sp. nov. is proposed, with THG-A13(T) as the type strain ( = KACC 17646(T) = JCM 19613(T)).

Hydrogenophaga luteola sp. nov. isolated from reed pond water.

A yellowish colored, Gram-staining negative, strictly aerobic, motile, rod-shaped bacterium, designated THG-SQE7(T), was isolated from reed pond water in Shangqiu, PR China. Comparative 16S rRNA gene sequence analysis indicated that strain THG-SQE7(T) is most closely related to Hydrogenophaga pseudoflava ATCC 33668(T) (98.4 %), followed by Hydrogenophaga bisanensis K102(T) (97.6 %) and Hydrogenophaga flava CCUG 1658(T) (97.6 %). DNA-DNA hybridization showed 53.5, 36.0 and 22.5 % DNA re-association with H. pseudoflava KCTC 2348(T), H. bisanensis KCTC 12980(T) and H. flava KCTC 1648(T), respectively. Chemotaxonomic data revealed that strain THG-SQE7(T) possesses ubiquinone-8 as the only isoprenoid quinone, summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), C16:0 and C18:1 ω7c as the major fatty acids. The major polar lipids were found to be phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The DNA G+C content was determined to be 63.7 mol%. These data corroborated the affiliation of strain THG-SQE7(T) to the genus Hydrogenophaga. Thus, the isolate represents a novel species, for which the name Hydrogenophaga luteola sp. nov. is proposed, with THG-SQE7(T) as the type strain (=KCTC 42501(T) = CCTCC AB 2014314(T) = JCM 30433(T)).

Roseomonas sediminicola sp. nov., isolated from fresh water.

A Gram-stain negative, strictly aerobic, non-motile, non-spore-forming, and rod-shaped bacterial strain designated FW-3(T) was isolated from fresh water and its taxonomic position was investigated by using a polyphasic approach. Strain FW-3(T) was found to grow at 10-37 °C and at pH 7.0 in the absence of NaCl on nutrient agar. On the basis of 16S rRNA gene sequence similarity, strain FW-3(T) was shown to belong to the family Acetobacteraceae and to be related to Roseomonas lacus TH-G33(T) (97.2 % sequence similarity) and Roseomonas terrae DS-48(T) (96.4 %). The G+C content of the genomic DNA was determined to be 68.0 %. The major menaquinone was determined to be Q-10 and the major fatty acids were identified as summed feature 7 (comprising C18:1 ω9c/ω12t/ω7c as defined by the MIDI system; 55.4 %), and C18:1 2OH (29.8 %). DNA and chemotaxonomic data supported the affiliation of strain FW-3(T) to the genus Roseomonas. Strain FW-3(T) could be differentiated genotypically and phenotypically from the recognized species of the genus Roseomonas. The novel isolate therefore represents a novel species, for which the name Roseomonas sediminicola sp. nov. is proposed, with the type strain FW-3(T) (=KACC 16616(T) = JCM 18210(T)).

Sphingomonas ginsenosidivorax sp. nov., with the ability to transform ginsenosides.

A Gram-negative, strictly aerobic, non-motile, non-spore-forming and rod-shaped bacterial strain designated KHI67(T) was isolated from sediment of the Gapcheon River in South Korea and its taxonomic position was investigated by using a polyphasic approach. Strain KHI67(T) was observed to grow optimally at 25-30 °C and at pH 7.0 on nutrient and R2A agar. On the basis of 16S rRNA gene sequence similarity, strain KHI67(T) was shown to belong to the family Sphingomonadaceae and was related to Sphingomonas faeni MA-olki(T) (97.6 % sequence similarity), Sphingomonas aerolata NW12(T) (97.5 %) and Sphingomonas aurantiaca MA101b(T) (97.3 %). The G + C content of the genomic DNA was determined to be 65.6 %. The major ubiquinone was found to be Q-10, the major polyamine was identified as homospermidine and the major fatty acids identified were summed feature 8 (comprising C18:1 ω7c/ω6c; 37.0 %), C16:0 (13.0 %), summed feature 3 (comprising C16:1 ω7c/C16:1 ω6c; 12.8 %) and C14:0 2OH (9.3 %). DNA and chemotaxonomic data supported the affiliation of strain KHI67(T) to the genus Sphingomonas. The DNA-DNA relatedness values between strain KHI67(T) and its closest phylogenetic neighbours were below 15 %. Strain KHI67(T) could be differentiated genotypically and phenotypically from the recognised species of the genus Sphingomonas. The isolate therefore represents a novel species, for which the name Sphingomonas ginsenosidivorax sp. nov. is proposed, with the type strain KHI67(T) (=KACC 14951(T) = JCM 17076(T) = LMG 25801(T)).

Phycicoccus ginsenosidimutans sp. nov., isolated from soil of a ginseng field.

A Gram-positive, non-motile, non-spore-forming, aerobic, coccoid-shaped bacterium, designated BXN5-13(T), was isolated from the soil of a ginseng field from Baekdu Mountain in Jilin district, China. Strain BXN5-13(T) grew optimally at 30 °C and pH 6.5-7.5 with 0-2  % (w/v) NaCl. Strain BXN5-13(T) had ß-glucosidase activity that was connected with ginsenoside-converting ability, so that it was able to convert ginsenoside Rb(1) to ginsenoside F2. On the basis of 16S rRNA gene sequence analysis, the closest phylogenetic relatives of strain BXN5-13(T) were Phycicoccus aerophilus 5516T-20(T) (98.4  % 16S rRNA gene sequence similarity), P. bigeumensis MSL-03(T) (98.3  %), P. dokdonensis DS-8(T) (97.9  %) and P. jejuensis KSW2-15(T) (96.9  %). Lower sequence similarity (<97.0  %) was found with the type strains of other recognized species of the family Intrasporangiaceae. The predominant quinone was MK-8(H4). The major fatty acids (>10  %) were iso-C15:0, C17:0, anteiso-C15:0 and iso-C16:0. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and phosphatidylinositol. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The chemotaxonomic data and the high genomic DNA G+C content of strain BXN5-13(T) (70.8l %) supported its affiliation with the genus Phycicoccus. DNA-DNA relatedness between strain BXN5-13(T) and its closest phylogenetic neighbours was below 16  %. Strain BXN5-13(T) represents a novel species within the genus Phycicoccus, for which the name Phycicoccus ginsenosidimutans sp. nov. is proposed. The type strain is BXN5-13(T) (=KCTC 19419(T)=DSM 21006(T)=LMG 24462(T)).

Rhodanobacter panaciterrae sp. nov., a bacterium with ginsenoside-converting activity isolated from soil of a ginseng field.

A novel gammaproteobacterium, designated LnR5-47(T), was isolated from soil of a ginseng field in Liaoning province, China. The isolate was a Gram-negative, aerobic, non-motile, non-spore-forming rod. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain LnR5-47(T) belonged to the genus Rhodanobacter. The isolate was most closely related to Rhodanobacter ginsengisoli GR17-7(T), Rhodanobacter terrae GP18-1(T), Dyella ginsengisoli Gsoil 3046(T), Rhodanobacter soli DCY45(T), Dyella soli JS12-10(T) and Dyella japonica IAM 15069(T) (98.0, 97.9, 97.7, 97.3, 97.2 and 97.1% 16S rRNA gene sequence similarity, respectively). Chemotaxonomic data (Q-8 as the predominant ubiquinone, and iso-C(16:0), iso-C(17:1)ω9c and iso-C(15:0) as the major fatty acids) also supported the affiliation of strain LnR5-47(T) with the genus Rhodanobacter. However, DNA-DNA relatedness between strain LnR5-47(T) and its closest phylogenetic neighbours was <25.8%. Moreover, physiological and biochemical tests phenotypically differentiated the isolate from other members of the genus Rhodanobacter. Therefore, strain LnR5-47(T) represents a novel species, for which the name Rhodanobacter panaciterrae sp. nov. is proposed; the type strain is LnR5-47(T) (=KACC 12826(T)=KCTC 22232(T)=LMG 24460(T)).

Gram-Scale Production of Ginsenoside F1 Using a Recombinant Bacterial ß-Glucosidase.

Naturally occurring ginsenoside F1 (20-O-ß-D-glucopyranosyl-20(S)-protopanaxatriol) is rare. Here, we produced gram-scale quantities of ginsenoside F1 from a crude protopanaxatriol saponin mixture comprised mainly of Re and Rg1 through enzyme-mediated biotransformation using recombinant ß-glucosidase (BgpA) cloned from a soil bacterium, Terrabacter ginsenosidimutans Gsoil 3082T. In a systematic step-by-step process, the concentrations of substrate, enzyme, and NaCl were determined for maximal production of F1. At an optimized NaCl concentration of 200 mM, the protopanaxatriol saponin mixture (25 mg/ml) was incubated with recombinant BgpA (20 mg/ml) for 3 days in a 2.4 L reaction. Following octadecylsilyl silica gel column chromatography, 9.6 g of F1 was obtained from 60 g of substrate mixture at 95% purity, as assessed by chromatography. These results represent the first report of gramscale F1 production via recombinant enzyme-mediated biotransformation.

Preparation of minor ginsenosides C-Mc, C-Y, F2, and C-K from American ginseng PPD-ginsenoside using special ginsenosidase type-I from Aspergillus niger g.848.

BACKGROUND: Minor ginsenosides, those having low content in ginseng, have higher pharmacological activities. To obtain minor ginsenosides, the biotransformation of American ginseng protopanaxadiol (PPD)-ginsenoside was studied using special ginsenosidase type-I from Aspergillus niger g.848. METHODS: DEAE (diethylaminoethyl)-cellulose and polyacrylamide gel electrophoresis were used in enzyme purification, thin-layer chromatography and high performance liquid chromatography (HPLC) were used in enzyme hydrolysis and kinetics; crude enzyme was used in minor ginsenoside preparation from PPD-ginsenoside; the products were separated with silica-gel-column, and recognized by HPLC and NMR (Nuclear Magnetic Resonance). RESULTS: The enzyme molecular weight was 75 kDa; the enzyme firstly hydrolyzed the C-20 position 20-O-ß-D-Glc of ginsenoside Rb1, then the C-3 position 3-O-ß-D-Glc with the pathway Rb1→Rd→F2→C-K. However, the enzyme firstly hydrolyzed C-3 position 3-O-ß-D-Glc of ginsenoside Rb2 and Rc, finally hydrolyzed 20-O-L-Ara with the pathway Rb2→C-O→C-Y→C-K, and Rc→C-Mc1→C-Mc→C-K. According to enzyme kinetics, K m and V max of Michaelis-Menten equation, the enzyme reaction velocities on ginsenosides were Rb1 > Rb2 > Rc > Rd. However, the pure enzyme yield was only 3.1%, so crude enzyme was used for minor ginsenoside preparation. When the crude enzyme was reacted in 3% American ginseng PPD-ginsenoside (containing Rb1, Rb2, Rc, and Rd) at 45°C and pH 5.0 for 18 h, the main products were minor ginsenosides C-Mc, C-Y, F2, and C-K; average molar yields were 43.7% for C-Mc from Rc, 42.4% for C-Y from Rb2, and 69.5% for F2 and C-K from Rb1 and Rd. CONCLUSION: Four monomer minor ginsenosides were successfully produced (at low-cost) from the PPD-ginsenosides using crude enzyme.

Identification and characterization of a ginsenoside-transforming ß-glucosidase from Pseudonocardia sp. Gsoil 1536 and its application for enhanced production of minor ginsenoside Rg2(S).

The ginsenoside Rg2(S), which is one of the pharmaceutical components of ginseng, is known to have neuroprotective, anti-inflammation, and anti-diabetic effects. However, the usage of ginsenoside Rg2(S) is restricted owing to the small amounts found in white and red ginseng. To enhance the production of ginsenoside Rg2(S) as a 100 gram unit with high specificity, yield, and purity, an enzymatic bioconversion method was developed to adopt the recombinant glycoside hydrolase (BglPC28), which is a ginsenoside-transforming recombinant ß-glucosidase from Pseudonocardia sp. strain Gsoil 1536. The gene, termed bglPC28, encoding ß-glucosidase (BglPC28) belonging to the glycoside hydrolase family 3 was cloned. bglPC28 consists of 2,232 bp (743 amino acid residues) with a predicted molecular mass of 78,975 Da. This enzyme was overexpressed in Escherichia coli BL21(DE3) using a GST-fused pGEX 4T-1 vector system. The optimum conditions of the recombinant BglPC28 were pH 7.0 and 37 °C. BglPC28 can effectively transform the ginsenoside Re to Rg2(S); the Km values of PNPG and Re were 6.36 ± 1.10 and 1.42 ± 0.13 mM, respectively, and the Vmax values were 40.0 ± 2.55 and 5.62 ± 0.21 µmol min-1 mg-1 of protein, respectively. A scaled-up biotransformation reaction was performed in a 10 L jar fermenter at pH 7.0 and 30°C for 12 hours with a concentration of 20 mg/ml of ginsenoside Re from American ginseng roots. Finally, 113 g of Rg2(S) was produced from 150 g of Re with 84.0 ± 1.1% chromatographic purity. These results suggest that this enzymatic method could be usefully exploited in the preparation of ginsenoside Rg2(S) in the cosmetics, functional food, and pharmaceutical industries.

p53-dependent Fas expression is critical for Ginsenoside Rh2 triggered caspase-8 activation in HeLa cells.

We have recently reported that Ginsenoside Rh2 (G-Rh2) induces the activation of two initiator caspases, caspase-8 and caspase-9 in human cancer cells. However, the molecular mechanism of its death-inducing function remains unclear. Here we show that G-Rh2 stimulated the activation of both caspase-8 and caspase-9 simultaneously in HeLa cells. Under G-Rh2 treatment, membrane death receptors Fas and TNFR1 are remarkably upregulated. However, the induced expression of Fas but not TNFR1 was contributed to the apoptosis process. Moreover, significant increases in Fas expression and caspase-8 activity temporally coincided with an increase in p53 expression in p53-non-mutated HeLa and SK-HEP-1 cells upon G-Rh2 treatment. In contrast, Fas expression and caspase-8 activity remained constant with G-Rh2 treatment in p53-mutated SW480 and PC-3 cells. In addition, siRNA-mediated knockdown of p53 diminished G-Rh2-induced Fas expression and caspase-8 activation. These results indicated that G-Rh2-triggered extrinsic apoptosis relies on p53-mediated Fas over-expression. In the intrinsic apoptotic pathway, G-Rh2 induced strong and immediate translocation of cytosolic BAK and BAX to the mitochondria, mitochondrial cytochrome c release, and subsequent caspase-9 activation both in HeLa and in SW480 cells. p53-mediated Fas expression and subsequent downstream caspase-8 activation as well as p53-independent caspase-9 activation all contribute to the activation of the downstream effector caspase-3/-7, leading to tumor cell death. Taken together, we suggest that G-Rh2 induces cancer cell apoptosis in a multi-path manner and is therefore a promising candidate for anti-tumor drug development.

Enzymatic Biotransformation of Ginsenoside Rb1 and Gypenoside XVII into Ginsenosides Rd and F2 by Recombinant ß-glucosidase from Flavobacterium johnsoniae.

This study focused on the enzymatic biotransformation of the major ginsenoside Rb1 into Rd for the mass production of minor ginsenosides using a novel recombinant ß-glucosidase from Flavobacterium johnsoniae. The gene (bglF3) consisting of 2,235 bp (744 amino acid residues) was cloned and the recombinant enzyme overexpressed in Escherichia coli BL21(DE3) was characterized. This enzyme could transform ginsenoside Rb1 and gypenoside XVII to the ginsenosides Rd and F2, respectively. The glutathione S-transferase (GST) fused BglF3 was purified with GST-bind agarose resin and characterized. The kinetic parameters for ß-glucosidase had apparent Km values of 0.91±0.02 and 2.84±0.05 mM and Vmax values of 5.75±0.12 and 0.71±0.01 µmol·min(-1)·mg of protein(-1) against p-nitrophenyl-ß-D-glucopyranoside and Rb1, respectively. At optimal conditions of pH 6.0 and 37℃, BglF3 could only hydrolyze the outer glucose moiety of ginsenoside Rb1 and gypenoside XVII at the C-20 position of aglycon into ginsenosides Rd and F2, respectively. These results indicate that the recombinant BglF3 could be useful for the mass production of ginsenosides Rd and F2 in the pharmaceutical or cosmetic industry.

Ramlibacter ginsenosidimutans sp. nov., with ginsenoside-converting activity.

A novel beta-proteobacterium, designated BXN5-27(T), was isolated from soil of a ginseng field of Baekdu Mountain in China, and was characterized using a polyphasic approach. The strain was Gram-staining-negative, aerobic, motile, non-spore-forming, and rod shaped. Strain BXN5-27(T) exhibited beta-glucosidase activity that was responsible for its ability to transform ginsenoside Rb1 (one of the dominant active components of ginseng) to compound Rd. Phylogenetic analysis based on 16S rRNA gene sequences showed that this strain belonged to the family Comamonadaceae; it was most closely related to Ramlibacter henchirensis TMB834(T) and Ramlibacter tataouinensis TTB310(T) (96.4% and 96.3% similarity, respectively). The G+C content of the genomic DNA was 68.1%. The major menaquinone was Q-8. The major fatty acids were C16:0, summed feature 4 (comprising C16:1 omega7c and/or iso-C15:0 2OH), and C17:0 cyclo. Genomic and chemotaxonomic data supported the affiliation of strain BXN5-27(T) to the genus Ramlibacter. However, physiological and biochemical tests differentiated it phenotypically from the other established species of Ramlibacter. Therefore, the isolate represents a novel species, for which the name Ramlibacter ginsenosidimutans sp. nov. is proposed, with the type strain being BXN5-27(T) (= DSM 23480(T) = LMG 24525(T) = KCTC 22276(T)).

Kinetics of a cloned special ginsenosidase hydrolyzing 3-O-glucoside of multi-protopanaxadiol-type ginsenosides, named ginsenosidase type III.

In this paper, the kinetics of a cloned special glucosidase, named ginsenosidase type III hydrolyzing 3-O-glucoside of multi-protopanaxadiol (PPD)-type ginsenosides, were investigated. The gene (bgpA) encoding this enzyme was cloned from a Terrabacter ginsenosidimutans strain and then expressed in E. coli cells. Ginsenosidase type III was able to hydrolyze 3-O-glucoside of multi-PPD-type ginsenosides. For instance, it was able to hydrolyze the 3-O-ß-D-(1-->2)-glucopyranosyl of Rb1 to gypenoside XVII, and then to further hydrolyze the 3-O-ß-D-glucopyranosyl of gypenoside XVII to gypenoside LXXV. Similarly, the enzyme could hydrolyze the glucopyranosyls linked to the 3-O- position of Rb2, Rc, Rd, Rb3, and Rg3. With a larger enzyme reaction Km value, there was a slower enzyme reaction speed; and the larger the enzyme reaction Vmax value, the faster the enzyme reaction speed was. The Km values from small to large were 3.85 mM for Rc, 4.08 mM for Rb1, 8.85 mM for Rb3, 9.09 mM for Rb2, 9.70 mM for Rg3(S), 11.4 mM for Rd and 12.9 mM for F2; and Vmax value from large to small was 23.2 mM/h for Rc, 16.6 mM/h for Rb1, 14.6 mM/h for Rb3, 14.3 mM/h for Rb2, 1.81mM/h for Rg3(S), 1.40 mM/h for Rd, and 0.41 mM/h for F2. According to the Vmax and Km values of the ginsenosidase type III, the hydrolysis speed of these substrates by the enzyme was Rc>Rb1>Rb3>Rb2>Rg3(S)>Rd>F2 in order.

A novel ginsenosidase from an Aspergillus strain hydrolyzing 6-O-multi-glycosides of protopanaxatriol-type ginsenosides, named ginsenosidase type IV.

Herein, a novel ginsenosidase, named ginsenosidase type IV, hydrolyzing 6-O-multi-glycosides of protopanaxatrioltype ginsenosides (PPT), such as Re, R1, Rf, and Rg2, was isolated from the Aspergillus sp. 39g strain, purified, and characterized. Ginsenosidase type IV was able to hydrolyze the 6-O-alpha-L-(1-->2)-rhamnoside of Re and the 6-O-beta-D- (1-->2)-xyloside of R1 into ginsenoside Rg1. Subsequently, it could hydrolyze the 6-O-beta-D-glucoside of Rg1 into F1. Similarly, it was able to hydrolyze the 6-O-alpha-L-(1-->2)- rhamnoside of Rg2 and the 6-O-beta-D-(1-->2)-glucoside of Rf into Rh1, and then further hydrolyze Rh1 into its aglycone. However, ginsenosidase type IV could not hydrolyze the 3-O- or 20-O-glycosides of protopanaxadioltype ginsenosides (PPD), such as Rb1, Rb2, Rb3, Rc, and Rd. These exhibited properties are significantly different from those of glycosidases described in Enzyme Nomenclature by the NC-IUBMB. The optimal temperature and pH for ginsenosidase type IV were 40°C and 6.0, respectively. The activity of ginsenosidase type IV was slightly improved by the Mg(2+) ion, and inhibited by Cu(2+) and Fe(2+) ions. The molecular mass of the enzyme, based on SDS-PAGE, was noted as being approximately 56 kDa.

Hymenobacter daecheongensis sp. nov., isolated from stream sediment.

A Gram-negative, strictly aerobic, non-spore-forming, rod-shaped, red-pink bacterium, designated strain Dae14(T), was isolated from stream sediment collected near Daecheong Dam, South Korea, and its taxonomic position was investigated by using a polyphasic approach. Phylogenetic analysis of 16S rRNA gene sequences showed that strain Dae14(T) belonged to the genus Hymenobacter. Sequence similarities between strain Dae14(T) and the type strains of Hymenobacter species with validly published names ranged from 91.3 to 94.3 %. The predominant cellular fatty acids of strain Dae14(T) were iso-C(15 : 0), C(16 : 1)omega5c, summed feature 5 (iso-C(17 : 1) I and/or anteiso-C(17 : 1) B) and iso-C(16 : 0). The DNA G+C content was 62.2 mol%. Results of phylogenetic, chemotaxonomic and phenotypic characterization indicated that strain Dae14(T) can be distinguished from all known Hymenobacter species and represents a novel species, for which the name Hymenobacter daecheongensis sp. nov. is proposed, with Dae14(T) (=KCTC 22258(T)=LMG 24498(T)) as the type strain.