Presence Of MK-7 Research Articles

Pedobacter daechungensis sp. nov., from freshwater lake sediment in South Korea

A novel bacterial strain, designated Dae 13T, was isolated from sediment from a freshwater lake in Daejeon, South Korea, and was characterized taxonomically by using a polyphasic approach. The isolate was Gram-negative, aerobic, non-motile, non-spore-forming and rod-shaped. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate belonged to the genus Pedobacter in the family Sphingobacteriaceae but was clearly separate from established species of this genus. The 16S rRNA gene sequence similarities between strain Dae 13(T) and type strains of Pedobacter species with validly published names ranged from 91.6 to 97.5 %. The G+C content of the genomic DNA was 33.8 mol%. Chemotaxonomic data, i.e. the presence of MK-7 as the major menaquinone and iso-C(15 : 0), C(16 : 0) and summed feature 3 (iso-C(15 : 0) 2-OH and/or C(16 : 1)omega7c) as the major fatty acids, supported the affiliation of strain Dae 13T to the genus Pedobacter. However, the results of physiological and biochemical tests allowed phenotypic differentiation of the isolate with respect to Pedobacter species with validly published names. Therefore, strain Dae 13T represents a novel species within the genus Pedobacter, for which the name Pedobacter daechungensis sp. nov. is proposed. The type strain is Dae 13T (=KCTC 12637T=LMG 23489T).

Paenibacillus ginsengarvi sp. nov., isolated from soil from ginseng cultivation

A Gram-positive, aerobic, non-motile, rod-shaped, spore-forming bacterium, designated Gsoil 139(T), was isolated from soil from a ginseng field in Pocheon Province, South Korea, and was characterized using a polyphasic approach. Comparative analysis of 16S rRNA gene sequences revealed that strain Gsoil 139(T) belongs to the family Paenibacillaceae. The greatest sequence similarity was found with respect to the type strains of Paenibacillus hodogayensis (95.6 %) and Paenibacillus koleovorans (93.8 %). The strain showed less than 93.8 % sequence similarity with respect to other species of the genus Paenibacillus. The G+C content of the genomic DNA was 48.1 mol%. In addition, the presence of MK-7 as the major menaquinone and C(15 : 0) anteiso as a major fatty acid (27.9 %) justifies its affiliation to the genus Paenibacillus. On the basis of its phenotypic characteristics and phylogenetic distinctiveness, strain Gsoil 139(T) represents a novel species within the genus Paenibacillus, for which the name Paenibacillus ginsengarvi sp. nov. is proposed. The type strain is Gsoil 139(T) (=KCTC 13059(T) =DSM 18677(T)).

Paenibacillus panacisoli sp. nov., a xylanolytic bacterium isolated from soil in a ginseng field in South Korea

A Gram-positive, facultatively anaerobic, motile, spore-forming bacterium, designated Gsoil 1411T, was isolated from soil of a ginseng field in Pocheon Province (South Korea) and was characterized using a polyphasic approach. Comparative analysis of 16S rRNA gene sequences revealed that strain Gsoil 1411T belongs to the family Paenibacillaceae, with closest sequence similarity to the type strains of Paenibacillus xylanilyticus (95.7%), Paenibacillus illinoisensis (95.2%) and Paenibacillus pabuli (94.8%). Strain Gsoil 1411T showed less than 94% sequence similarity to the type strains of other recognized members of the genus Paenibacillus. In addition, the presence of MK-7 as the major menaquinone, anteiso-C15:0 as a major fatty acid (44.8%) and the presence of PAEN513F and PAEN862F signature sequences suggest that it is affiliated to the genus Paenibacillus. The G+C content of the genomic DNA was 53.9 mol%. On the basis of its phenotypic characteristics and phylogenetic distinctiveness, strain Gsoil 1411T is suggested to represent a novel species within the genus Paenibacillus, for which the name Paenibacillus panacisoli sp. nov. is proposed. The type strain is Gsoil 1411T (=KCTC 13020T=LMG 23405T).

Studies on action of menaquinone‐7 in regulation of bone metabolism and its preventive role of osteoporosis

The effect of menaquinone-7 (MK-7) on bone components and bone resorbing factors induced-bone resorption using the femoral-diaphyseal and - metaphyseal tissues obtained from elderly female rats in vitro were examined. Calcium content, alkaline phosphatase activity and deoxyribonucleic acid (DNA) in the diaphyseal and metaphyseal tissues in elderly females rats were significantly decreased as compared with that of young rats, indicating that aging causes a deterioration of bone formation. The presence of MK-7 (10(-6)-10(-5) M) caused a significant prevention of reduction of biochemical components. On the other hand, the bone-resorbing factor, parathyroid hormone (1-34) (PTH; 10(-7) M) and prostaglandin E(2) (PGE(2); 10(-5) M) caused a significant decrease in calcium content in the diaphyseal and metaphyseal tissues. This decreases was completely inhibited in the presence of MK-7 (10(-7)-10(-5) M). In addition, MK-7 (10(-7)-10(-5) M) completely prevented the PTH (10(-7) M) or PGE(2) (10(-5) M) induced increases in medium glucose consumption and lactic acid production by bone tissues, Furthermore, the effect of the prolonged intake of dietary MK-7 on bone loss in ovariectomized rats was investigated. As a result, it was found that the intake of experimental diets containing the fermented soybean (natto) with supplemental MK-7 caused significant elevations of MK-7 and gamma-carboxylated osteocalcin concentration, a bio marker of bone formation, in the serum of both ovariectomized rats and normal subjects, suggesting that MK-7 may play an important role in the prevention of age-related bone loss.

Stimulatory effect of menaquinone-7 on bone formation in elderly female rat femoral tissues in vitro: Prevention of bone deterioration with aging

Menaquinone-7 (MK-7) is vitamin K2 which is a series of vitamins with multiisoprene units at the 3-position of the naphthoquinone. MK-7 has been shown to prevent bone loss in ovariectomized rats, an animal model for osteoporosis. This study was undertaken to determine whether MK-7 has a stimulatory effect on bone components of elderly female rats in vitro. The femoral-diaphyseal and -metaphyseal tissues obtained from young (4 weeks old) or elderly (50 weeks old) female rats were cultured for 48 h in a Dullbecco's modified Eagle's medium (high glucose, 4.5%) supplemented with antibiotics and bovine serum albumin. Calcium content, alkaline phosphatase activity and deoxyribonucleic acid (DNA) in the diaphyseal and metaphyseal tissues obtained from elderly rats were significantly decreased as compared with those of young rats, indicating that aging causes a deterioration of bone formation. The presence of MK-7 (10(-6) or 10(-5) M) caused a significant increase in biochemical components in the femoral-diaphyseal and -metaphyseal tissues obtained from elderly rat in vitro. The anabolic effect of MK-7 (10(-6) or 10(-5) M) on the femoral calcium content was significantly enhanced in the presence of phytoestrogen genistein (10(-6) or 10(-5) M), suggesting that the mode of action of MK-7 differ from that of genistein. The effect of MK-7 (10(-5) M) in increasing calcium content, alkaline phosphatase activity and DNA content in the diaphyseal and metaphyseal tissues was completely abolished in the presence of cycloheximide (10(-6) M), an inhibitor of protein synthesis in vitro. These findings demonstrate that MK-7 has a stimulatory effect on bone formation in the femoral tissues of elderly female rats in vitro. MK-7 may have a preventive role for bone deterioration with aging.

Stimulatory effect of menaquinone-7 (vitamin K2) on osteoblastic bone formation in vitro.

Menaquinone-7, which is vitamin K2 (menatetrenone) with seven isoprene units, is highly contained in the fermented soybean. The effect of menaquinone-7 (MK-7) on osteoblastic bone formation was investigated. Femoral-diaphyseal and metaphyseal tissues of young male rats (4 weeks old) were cultured for 48 h in a medium containing either vehicle or MK-7 (10(-7)-10(-5) M). Calcium content, alkaline phosphatase activity, and deoxyribonuclic acid (DNA) content in the diaphyseal and metaphyseal tissues was significantly increased in the presence of MK-7 (10(-6) and 10(-5) M). The effect of MK-7 in increasing the diaphyseal and metaphyseal calcium content and alkaline phosphatase activity was completely prevented in the presence of cycloheximide (10(-6) M), an inhibitor of protein synthesis. Moreover, osteoblastic MC3T3-E1 cells after subculture were cultured for 24 h in a serum-free medium containing MK-7 (10(-7)-10(-5) M). Protein content, alkaline phophatase activity, osteocalcin and DNA content in the cells was significantly increased in the presence of MK-7 (10(-6) and 10(-5) M). The effect of MK-7 in increasing protein content, alkaline phosphatase activity, and osteocalcin production in the cells was completely blocked by cycloheximide. This study demonstrates that MK-7 has an anabolic effect on bone tissue and osteoblastic MC3T3-E1 cells in vitro, suggesting that the compound can stimulate osteoblastic bone formation.

Inhibitory effect of menaquinone-7 (vitamin K2) on osteoclast-like cell formation and osteoclastic bone resorption in rat bone tissues in vitro.

The effect of menaquinone-7 (MK-7; vitamin K2) on osteoclast-like cell formation and osteoclastic bone resorption in rat femoral tissues in vitro was investigated. The bone marrow cells were cultured for 7 days in a a-minimal essential medium (alpha-MEM) containing a well-known bone resorbing agent [parathyroid hormone (1-34) (PTH) or prostaglandin E2 (PGE2)] with an effective concentration. Osteoclast-like cells were estimated by staining for tartrate-resistant acid phosphatase (TRACP), a marker enzyme of osteoclasts. The presence of PTH (10(-8) M) or PGE2 (10(-6) M) induced a remarkable increase in osteoclast-like multinucleated cells. These increases were significantly inhibited by MK-7 (10(-8) - 10(-5) M). MK-7 (10(-7) and 10(-6) M) significantly inhibited phorbol 12-myristate 13-acetate-induced osteoclast-like cell formation, whereas MK-7 did not inhibit dibutyryl cyclic adenosine monophosphate (DcAMP) (10(-5) M)-induced osteoclast-like cell formation. These results suggest that the inhibitory action of MK-7 is partly involved in protein kinase C signaling. The bone cells isolated from rat femoral tissues were cultured for 48 h in an alpha-MEM containing either vehicle or MK-7 (10(-8) - 10(-5) M). The presence of MK-7 (10(-6) and 10(-5) M) caused a significant decrease in the number of mature osteoclasts. Such a decrease was also seen in the presence of calcitonin (10(-10) - 10(-8) M), DcAMP (10(-6) and 10(-5) M), or calcium chloride (10(-4) and 10(-3) M). The effect of MK-7 (10(-6) M) in decreasing the number of osteoclasts was not further enhanced in the presence of calcitonin (10(-8) M), DcAMP (10(-5) M), or calcium chloride (10(-3) M), and was completely abolished by the presence of dibucaine (10(-6) M) or staurosporine (10(-7) M), which are inhibitors of Ca2+-dependent protein kinases. These results suggested that MK-7 has a suppressive effect on osteoclasts. Moreover, the femoral-metaphyseal tissues obtained from rats were cultured for 48 h in Dulbecco's modified Eagle's medium containing either vehicle, PTH (10(-7) M), orPGE2 (10(-5) M) in the absence or presence of MK-7 (10(-7) - 10(-5) M). The presence of PTH or PGE2 induced a significant decrease in bone calcium content. These decreases were significantly blocked by MK-7 (10(-7) - 10(-5) M). This study demonstrates that MK-7 has an inhibitory effect on osteoclastic bone resorption in vitro.