Application of the filter plate microbial trap (FPMT), for cultivating thermophilic bacteria from thermal springs in Barguzin area, eastern Baikal, Russia.

Hot springs are regarded as treasury of valuable thermophiles. Like other bacteria, thermophiles are not easily cultivated using conventional culture methods. We used an advanced cultivation method, the filter plate microbial trap (FPMT), to isolate bacteria from thermal springs. In total, 184 isolates were obtained from five thermal springs using the FPMT and standard agar plate method, and their 16S rRNA gene sequences were analyzed. FPMT allowed us to obtain a culture collection that was larger, richer, and more novel than that obtained by standard cultivation. Seven novel species were obtained using the FPMT technique, whereas only one was isolated using a standard cultivation. We also found clear differences in the patterns of phylogenetic diversity and physiological properties between isolates from two cultivation methods. The results have encouraged us to apply the FPMT method in other extreme environments and offer further support for fostering the development of new cultivation methods.

Flavobacterium paronense sp. nov., isolated from freshwater of an artificial vegetated island.

A Gram-stain-negative, motile by gliding, yellow-pigmented bacterial strain, designated KNUS1T, was isolated from Lake Paro in Korea. The phylogenetic tree based on 16S rRNA gene sequences showed that strain KNUS1T formed a distinct lineage within the genus Flavobacterium. Strain KNUS1T was closely related to Flavobacterium cheonhonense ARSA-15T (96.8 %16S rRNA gene sequence similarity), Flavobacterium pectinovorum DSM 6368T (96.3 %) and Flavobacterium dankookense ARSA-19T (96.1 %). The major fatty acids of strain KNUS1T were iso-C15 : 0 and iso-C15 : 1 G. The major polyamine was sym-homospermidine. The major polar lipids of strain KNUS1T were phosphatidylethanolamine, five unidentified aminolipids and three unidentified polar lipids. The major respiratory'quinone was menaquinone 6 (MK-6). The DNA G+C content of strain KNUS1T was 34.2 mol%. On the basis of the evidence presented in this study, strain KNUS1T represents a novel species of the genus Flavobacterium, for which the name Flavobacterium paronense sp. nov. is proposed. The type strain is KNUS1T ( = KACC 17692T = CECT 8460T).

Emticicia aquatica sp. nov., a species of the family Cytophagaceae isolated from fresh water.

A Gram-staining-negative, non-gliding, orange-pigmented bacterial strain, designated HMF2925T, was isolated from fresh water in Korea. The phylogenetic tree based on 16S rRNA gene sequences showed that strain HMF2925T formed a distinct lineage within the genus Emticicia. Strain HMF2925T was closely related to Emticicia oligotrophica DSM 17448T (95.5 %) and Emticicia ginsengisoli Gsoil 085T (94.1 %). The major fatty acids of strain HMF2925T were summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), iso-C15 : 0, C16 : 1ω5c and C16 : 0.The major polar lipids of strain HMF2925T were phosphatidylethanolamine, phosphatidylinositol, diphosphatidylglycerol, phosphatidylglycerol, an unidentified glycolipid, two unidentified amino lipids and three unidentified polar lipids. The DNA G+C content of strain HMF2925T was 36.5 mol%. On the basis of the evidence presented in this study, strain HMF2925T represents a novel species of the genus Emticicia, for which the name Emticicia aquatica sp. nov. is proposed. The type strain is HMF2925T ( = KCTC 42574T = CECT 8858T).

Mucilaginibacter soyangensis sp. nov., isolated from a lake.

A non-motile, yellow-orange-pigmented bacterial strain, designated HME6664(T), was isolated from Lake Soyang, Republic of Korea. The major fatty acids of strain HME6664(T) were summed feature 3 (comprising C16 : 1ω6c and/or C(16 : 1)ω7c; 44.7%) and iso-C15 : 0 (20.2%). The DNA G+C content was 40.8 mol%. A phylogenetic tree based on 16S rRNA gene sequences showed that strain HME6664(T) formed a lineage within the genus Mucilaginibacter. Strain HME6664(T) was closely related to Mucilaginibacter ximonensis (96.7%), Mucilaginibacter dorajii (96.5%) and Mucilaginibacter lappiensis (96.3%). On the basis of the evidence presented in this study, strain HME6664(T) represents a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter soyangensis sp. nov., is proposed. The type strain is HME6664(T) ( = KCTC 23261(T) = CECT 7824(T)).

Lacihabitans soyangensis gen. nov., sp. nov., a new member of the family Cytophagaceae, isolated from a freshwater reservoir.

A Gram-staining-negative, non-motile and orange-pigmented bacterium, designated strain HME6675(T), was isolated from freshwater of a reservoir in Korea. The major fatty acids of strain HME6675(T) were iso-C15 : 0 (33.4 %) and summed feature 3 (comprising C16 : 1ω6c and/or C16 : 1ω7c; 31.3 %). The major respiratory quinone was MK-7. The polar lipids were phosphatidylethanolamine, one unidentified aminolipid, one unidentified aminophospholipid and three unidentified polar lipids. The DNA G+C content of strain HME6675(T) was 37.7 mol%. A phylogenetic tree based on 16S rRNA gene sequences showed that strain HME6675(T) formed a lineage within the family Cytophagaceae and was related to Leadbetterella byssophila 4M15(T) (93.0 % sequence similarity), Fluviimonas pallidilutea TQQ6(T) (90.6 %) and Emticicia oligotrophica GPTSA100-15(T) (89.1 %). On the basis of the evidence presented in this study, strain HME6675(T) represents a novel genus and species of the family Cytophagaceae, for which the name Lacihabitans soyangensis gen. nov., sp. nov. is proposed. The type strain of Lacihabitans soyangensis is HME6675(T) ( = KCTC 23259(T) = CECT 7826(T)).

Installation of an artificial vegetating island in oligomesotrophic Lake Paro, Korea.

After cut off of inflowing water, Lake Paro, an oligomesotrophic lake lost littoral zone, an important region for the aquatic ecosystem. For the first step of restoration, the artificial vegetation island was installed. The concentration of nutrients in lake water was not sufficient for the growth of macrophyte as total phosphate was ranged from 58 to 83 µg L(-1). In order to overcome this problem, the hydrophobic substratum for bacterial attachment was selected as buoyant mat material of the artificial vegetation island. In this medium, total phosphate and total nitrogen were ranged from 190 to 1,060 µg L(-1) and from 4.9 to 9.1 mg L(-1), respectively. These concentrations were high enough for macrophytes growth. After launching 1,800 m(2) of AVI in Lake Paro, the macrophytes, Iris pseudoacorus and Iris ensata, grew well after five years of launching without the addition of fertilizer. Furthermore, fishes were plentiful under the artificial vegetation island, and ducks were observed on the artificial vegetation island. Bacteria using sunlight as energy source and self-designed ecotechnology can be used as an alternative method for the restoration of disturbed littoral zone in oligo-mesotrophic lakes.

Flavobacterium yonginense sp. nov. and Flavobacterium myungsuense sp. nov., isolated from a mesotrophic artificial lake.

Two non-motile, Gram-staining-negative, yellow-pigmented bacterial strains designated HMD1001T and HMD1033T were isolated from the water of a mesotrophic artificial lake in Korea. A phylogenetic tree based on 16S rRNA gene sequences indicated that both strains could be assigned to the genus Flavobacterium; strain HMD1001T appeared most closely related to Flavobacterium fluvii H7T (96.8 % sequence similarity), F. succinicans DSM 4002T (96.6 %) and F. hydatis DSM 2063T (96.6 %) whereas strain HMD1033T appeared most closely related to Flavobacterium psychrolimnae LMG 2201T (96.2 %), F. segetis AT1048T (96.2 %) and F. weaverense AT1042T (96.2 %). The major fatty acids of strain HMD1001T were iso-C15:0 (21.5 %), summed feature 3 (comprising C16:1ω6c and/or C16:1ω7c; 18.0 %) and iso-C15:1 G (7.6 %), whereas those of HMD1033T were summed feature 3 (23.8 %), iso-C15:0 3-OH (16.9 %), iso-C15:0 (15.3 %) and anteiso-C15:0 (12.1 %). The genomic DNA G+C contents of strains HMD1001T and HMD1033T were 35.9 and 32.2 mol%, respectively. Phylogenetic and phenotypic evidence indicates that strains HMD1001T and HMD1033T represent two novel species of the genus Flavobacterium, for which the names Flavobacterium yonginense sp. nov. (type strain HMD1001T=KCTC 22796T=CECT 7594T) and Flavobacterium myungsuense sp. nov. (type strain HMD1033T=KCTC 22825T=CECT 7649T) are proposed.

Echinicola jeungdonensis sp. nov., isolated from a solar saltern.

A non-motile and yellow-pigmented bacterium, designated strain HMD3054(T), was isolated from a solar saltern in Jeungdo, Republic of Korea. The major fatty acids of strain HMD3054(T) were iso-C15:0 (31.4 %), anteiso-C15:0 (23.5 %), iso-C17:0 3-OH (14.2 %), summed feature 3 (comprising C16:1ω6c and/or C16:1ω7c; 6.9 %) and summed feature 9 (comprising iso-C17:1ω9c and/or 10-methyl C16:0; 6.0 %). The major respiratory quinones were MK-6 and MK-7. The DNA G+C content of strain HMD3054(T) was 46.9 mol%. A phylogenetic tree based on 16S rRNA gene sequences showed that strain HMD3054(T) formed a lineage within the genus Echinicola. Strain HMD3054(T) was closely related to Echinicola vietnamensis KMM 6221(T) (94.3 % 16S rRNA gene sequence similarity) and Echinicola pacifica KMM 6172(T) (94.0 %). On the basis of the evidence presented in this study, strain HMD3054(T) represents a novel species of the genus Echinicola, for which the name Echinicola jeungdonensis sp. nov. is proposed. The type strain is HMD3054(T) ( = KCTC 23122(T)  = CECT 7682(T)).

Agreement, precision, and accuracy of epifluorescence microscopy methods for enumeration of total bacterial numbers.

To assess interchangeability of estimates of bacterial abundance by different epifluorescence microscopy methods, total bacterial numbers (TBNs) determined by most widely accepted protocols were statistically compared. Bacteria in a set of distinctive samples were stained with acridine orange (AO), 4'-6-diamidino-2-phenylindole (DAPI), and BacLight and enumerated by visual counting (VC) and supervised image analysis (IA). Model II regression and Bland-Altman analysis proved general agreements between IA and VC methods, although IA counts tended to be lower than VC counts by 7% on a logarithmic scale. Distributions of cells and latex beads on polycarbonate filters were best fitted to negative binomial models rather than to Poisson or log-normal models. The fitted models revealed higher precisions of TBNs by the IA method than those by the VC method. In pairwise comparisons of the staining methods, TBNs by AO and BacLight staining showed good agreement with each other, but DAPI staining had tendencies of underestimation. Although precisions of the three staining methods were comparable to one another (intraclass correlation coefficients, 0.97 to 0.98), accuracy of the DAPI staining method was rebutted by disproportionateness of TBNs between pairs of samples that carried 2-fold different volumes of identical cell suspensions. It was concluded that the TBN values estimated by AO and BacLight staining are relatively accurate and interchangeable for quantitative interpretation and that IA provides better precision than does VC. As a prudent measure, it is suggested to avoid use of DAPI staining for comparative studies investigating accuracy of novel cell-counting methods.

Community analysis of betaproteobacterial ammonia-oxidizing bacteria using the amoCAB operon.

The genes and intergenic regions of the amoCAB operon were analyzed to establish their potential as molecular markers for analyzing ammonia-oxidizing betaproteobacterial (beta-AOB) communities. Initially, sequence similarity for related taxa, evolutionary rates from linear regressions, and the presence of conserved and variable regions were analyzed for all available sequences of the complete amoCAB operon. The gene amoB showed the highest sequence variability of the three amo genes, suggesting that it might be a better molecular marker than the most frequently used amoA to resolve closely related AOB species. To test the suitability of using the amoCAB genes for community studies, a strategy involving nested PCR was employed. Primers to amplify the whole amoCAB operon and each individual gene were tested. The specificity of the products generated was analyzed by denaturing gradient gel electrophoresis, cloning, and sequencing. The fragments obtained showed different grades of sequence identity to amoCAB sequences in the GenBank database. The nested PCR approach provides a possibility to increase the sensitivity of detection of amo genes in samples with low abundance of AOB. It also allows the amplification of the almost complete amoA gene, with about 300 bp more sequence information than the previous approaches. The coupled study of all three amo genes and the intergenic spacer regions that are under different selection pressure might allow a more detailed analysis of the evolutionary processes, which are responsible for the differentiation of AOB communities in different habitats.

A novel archaeal group in the phylum Crenarchaeota found unexpectedly in an eukaryotic survey in the Cariaco Basin.

Archaea have been found in many more diverse habitats than previously believed due in part to modern molecular approaches to discovering microbial diversity. We report here an unexpected expansion of the habitat diversity of the Archaea in the Cariaco Basin we found using a primer set designed for 18S eukaryotic rDNA sequence analysis. The results presented here expand the originally identified 9 archaeal clones reported in this environment using bacterial/archaeal primers to 152 archaeal clones: 67 (18 OTU) of these clones were found at a depth of 900 m of station A while 71 (9 OTU) of them were at a depth of between 300 approximately 335 m of station B&C depending upon which location the samples were taken. We used three phylogenetic analysis methods and detected 20 phylotypes belonging to a single previously unreported group distantly related to the Crenarchaeota. Also, we determined that the original nine sequences did not fall into any of the known phyla of the Archaea suggesting that they may represent a novel group within the Kingdom Archaea. Thus, from these two studies, we suggest that Archaea in the Cariaco Basin could be unique; however, further studies using archaeal-specific primers and the design of new primers as well as the systematic use of several different primer combinations may improve the chances of understanding the archeal diversity in the Cariaco Basin.

Revegetation of a lakeside barren area by the application of plant growth-promoting rhizobacteria.

The growth stimulation of wild plants by several bacterial species showing plant growth-promoting capabilities was examined in a barren lakeside area at Lake Paro, Korea. Microbial numbers and activities in the field soil were monitored for 73 days after inoculation of the bacteria. The acridine orange direct counts for the total soil bacterial populations ranged between 2.0-2.3x10(9) cells/g soil and 1.4-1.8x10(9) cells/g soil in the inoculated and uninoculated soils, respectively. The numbers of Pseudomonas spp., which is known as a typical plant growth-promoting rhizobacteria, and the total microbial activity were higher in the inoculated soil compared to those in the uninoculated soil. The average shoot and root lengths of the wild plants grown in the inoculated soil were 17.3 cm and 12.4 cm, respectively, and longer than those of 11.4 cm and 8.5 cm in the uninoculated soil. The total dry weight of the harvested wild plants was also higher in the inoculated soil (42.0 g) compared to the uninoculated soil (35.1 g). The plant growth-promoting capabilities of the inoculated bacteria may be used for the rapid revegetation of barren or disturbed land, and as biofertilizer in agriculture.

Microcosm study for revegetation of barren land with wild plants by some plant growth-promoting rhizobacteria.

Growth promotion of wild plants by some plant growth-promoting rhizobacteria (PGPR) was examined in the microcosms composed of soils collected separately from a grass-covered site and a nongrass-covered site in a lakeside barren area at Lake Paro, Korea. After sowing the seeds of eight kinds of wild plants and inoculation of several strains of PGPR, the total bacterial number and microbial activity were measured during 5 months of study period, and the plant biomasses grown were compared at the end of the study. Acridine orange direct counts in the inoculated microcosms, 1.3-9.8 x 10(9) cells x g soil(-1) in the soil from the grass-covered area and 0.9-7.2 x 10(9) cells x g soil(-1) in the soil from the nongrass-covered site, were almost twice higher than those in the uninoculated microcosms. The number of Pseudomonas sp., well-known bacteria as PGPR, and the soil dehydrogenase activity were also higher in the inoculated soils than the uninoculated soils. The first germination of sowed seeds in the inoculated microcosm was 5 days earlier than the uninoculated microcosm. Average lengths of all plants grown during the study period were 26% and 29% longer in the inoculated microcosms starting with the grass-covered soil and the nongrass-covered soil, respectively, compared with those in the uninoculated microcosms. Dry weights of whole plants grown were 67-82% higher in the inoculated microcosms than the uninoculated microcosms. Microbial population and activity and growth promoting effect by PGPR were all higher in the soils collected from the grass-covered area than in the nongrass-covered area. The growth enhancement of wild plants seemed to occur by the activities of inoculated microorganisms, and this capability of PGPR may be utilized for rapid revegetation of some barren lands.

Association of a Methanol Extract of Rheum undulatum L. Mediated Cell Death in AGS Cells with an Intrinsic Apoptotic Pathway.

OBJECTIVES: Rheum undulatum L. has traditionally been used for the treatment of many diseases in Asia. However, its anti-proliferative activity in cancer has still not been studied. In the present study, we investigated the anti-cancer effects of methanol extract of Rheum undulatum L. (MERL) on human adenocarcinoma gastric cell lines (AGS). METHODS: To investigate the anti-cancer effect of MERL on AGS cells, we treated the AGS cells with varying con¬centrations of MERL and performed 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assays. Cell cycle analyses, measurements of the mitochondrial membrane potential (MMP), caspase activity assays and Western blots were conducted to determine whether AGS cell death occurred by apoptosis. RESULTS: Treatment with MERL significantly inhibited growth of AGS cells in a concentration dependent manner. MERL treatment in AGS cells leaded to increased accumulation of apoptotic sub G1 phase cells in a concentration dependent manner. In control cultures, 5.38% of the cells were in the sub G1 phase. In MERL treated cells, however, this percentage was significantly increased (9.95% at 70 µg/mL, 15.94% at 140 µg/mL, 26.56% at 210 µg/mL and 38.08% at 280 µg/mL). MERL treatment induced the decreased expression of pro-caspase-8 and -9 in a concentration dependent manner, whereas the expression of the active form of caspase-3 was increased. A subsequent Western blot analysis revealed increased cleaved levels of poly (ADP-ribose) polymerase (PARP) protein. Also, treatment with MERL increased the activities of caspase-3 and -9 compared with the control. MERL treatment increased the levels of the pro-apoptotic truncated Bid (tBid) and Bcl2 Antagonist X (Bax) proteins and decreased the levels of the anti-apoptotic B-cell lymphoma 2 (Bcl-2) protein, whose is the stabilization of mitochondria. However, inhibitions of p38, extracellular signal regulated kinases (ERKs) and C-Jun N-terminal kinases (JNK) by MERL treatment did not affect cell death. CONCLUSION: These results suggest that MERL mediated cell death is associated with an intrinsic apoptotic pathway in AGS cells.

Apoptosis of AGS human gastric adenocarcinoma cells by methanolic extract of Dictamnus.

BACKGROUND: The root bark of Dictamnus dasycarpus Turcz has traditionally been used in East Asia to treat skin diseases such as eczema, atopic dermatitis, and psoriasis. However, it has also been reported to exhibit an anti-proliferative effect on cancer cells. OBJECTIVE: To investigate the anti-cancer effects of a methanol extract of Dictamnus dasycarpus root bark (MEDD) on AGS cells (a human gastric adenocarcinoma cell-line). MATERIALS AND METHODS: An 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium assay, a caspase activity assay, cell cycle analysis, mitochondrial membrane potential (MMP) measurements, and western blotting were used to investigate the anti-cancer effects of MEDD on AGS cells. RESULTS: Treatment with MEDD significantly and concentration-dependently inhibited AGS cell growth. MEDD treatment in AGS cells led to increased accumulation of apoptotic sub-G1 phase cells in a concentration-dependent manner. Also, MEDD reduced the expressions of pro-caspase-3, -8 and -9, and increased the active form of caspase-3. Furthermore, subsequent Western blotting revealed elevated levels of poly (ADP-ribose) polymerase protein. MEDD treatment reduced levels of MMP and anti-apoptotic Bcl-2 and Bcl-xL proteins. Pretreatment with SB203580 (a specific inhibitor of p38 mitogen-activated protein kinases), SP600125 (a potent inhibitor of C-Jun N-terminal kinases), or PD98059 (a potent inhibitor of extracellular signal-regulated kinases) did not modify the effects of MEDD treatment. However, pretreatment with LY294002 (a specific inhibitor of Akt) significantly enhanced MEDD-induced cell death. CONCLUSION: These results suggest that MEDD-mediated cell death is associated with the intrinsic apoptotic pathway and that inhibition of Akt signaling contributes to apoptosis induction by MEDD.

Effects of Dangkwisoo­san, a traditional herbal medicine for treating pain and blood stagnation, on the pacemaker activities of cultured interstitial cells of Cajal.

The interstitial cells of Cajal (ICCs) are the pacemaker cells in the gastrointestinal (GI) tract. In the present study, the effects of Dangkwisoo­san (DS) on pacemaker potentials in cultured ICCs from the small intestine of the mouse were investigated. The whole­cell patch­clamp configuration was used to record pacemaker potentials from cultured ICCs and the increase in intracellular Ca2+ concentration ([Ca2+i) was analyzed in cultured ICCs using fura­2­acetoxymethyl ester. The generation of pacemaker potentials in the ICCs was observed. DS produced pacemaker depolarizations in a concentration dependent manner in current clamp mode. The 4­diphenylacetoxy­N­methyl­piperidine methiodide muscarinic M3 receptor antagonist inhibited DS­induced pacemaker depolarizations, whereas methoctramine, a muscarinic M2 receptor antagonist, did not. When guanosine 5'­[ß­thio] diphosphate (GDP­ß­S; 1 mM) was in the pipette solution, DS marginally induced pacemaker depolarizations, whereas low Na+ solution externally eliminated the generation of pacemaker potentials and inhibited the DS­induced pacemaker depolarizations. Additionally, the nonselective cation channel blocker, flufenamic acid, inhibited the DS­induced pacemaker depolarizations. Pretreatment with Ca2+­free solution and thapsigargin, a Ca2+­ATPase inhibitor in the endoplasmic reticulum, also eliminated the generation of pacemaker currents and suppressed the DS­induced pacemaker depolarizations. In addition, [Ca2+]i analysis revealed that DS increased [Ca2+]i. These results suggested that DS modulates pacemaker potentials through muscarinic M3 receptor activation in ICCs by G protein­dependent external and internal Ca2+ regulation and external Na+. Therefore, DS were observed to affect intestinal motility through ICCs.

Effects of Schisandra chinensis extract on gastrointestinal motility in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Schisandra chinensis (Turcz.) Baill. (SC) continues to be used as a traditional folk medicine in Asia, especially for the treatment of gastrointestinal (GI) disorders related to gastritis, diarrhea, enterocolitis and abnormal GI motility. AIM OF THE STUDY: Because GI disorders, especially abnormal GI motility, are major lifelong problems, we investigated the effects of SC on the pacemaker activity of the interstitial cells of Cajal (ICCs) in murine small intestine and GI motility. MATERIALS AND METHODS: Enzymatic digestions were used to dissociate ICCs from small intestines, and the whole-cell patch-clamp configuration was used to record potentials generated by cultured ICCs. In vivo effects of SC on GI motility were investigated by measuring the intestinal transit rate (ITR) of Evans blue in normal and GI motility dysfunction mice. RESULTS: SC extracts depolarized the membrane potentials of ICCs in a dose dependent manner. Pretreatment with Ca(2+) free solution or thapsigargin (a Ca(2+)-ATPase inhibitor in the endoplasmic reticulum) abolished the generation of pacemaker potentials by ICCs, and under these conditions, SC extract did not depolarize the membrane potentials of ICCs. In addition, membrane depolarizations were inhibited by intracellular GDPßS and by U-73122 (an active phospholipase C (PLC) inhibitor). In normal mice, ITRs were significantly increased by SC extract (0.1-1g/kg, intragastrically (i.g.)) in a dose dependent manner. Also, SC extract significantly recovered the GI motility dysfunctions in acetic acid (AA)-injected and streptozotocin (STZ)-induced diabetic mice, which are the GI motility animal models. MATERIALS AND METHODS: SC extract modulates pacemaker potentials in ICCs in a dose dependent manner via external and internal Ca(2+) regulations, and via G protein and the PLC pathway. In addition, SC extract increased ITRs in normal and abnormal GI motility mice models. This study shows that SC extract offers a basis for the development of a prokinetic agent that prevents or alleviates GI motility dysfunctions.

Ginsenoside Re inhibits pacemaker potentials via adenosine triphosphate-sensitive potassium channels and the cyclic guanosine monophosphate/nitric oxide-dependent pathway in cultured interstitial cells of Cajal from mouse small intestine.

BACKGROUND: Ginseng belongs to the genus Panax. Its main active ingredients are the ginsenosides. Interstitial cells of Cajal (ICCs) are the pacemaker cells of the gastrointestinal (GI) tract. To understand the effects of ginsenoside Re (GRe) on GI motility, the authors investigated its effects on the pacemaker activity of ICCs of the murine small intestine. METHODS: Interstitial cells of Cajal were dissociated from mouse small intestines by enzymatic digestion. The whole-cell patch clamp configuration was used to record pacemaker potentials in cultured ICCs. Changes in cyclic guanosine monophosphate (cGMP) content induced by GRe were investigated. RESULTS: Ginsenoside Re (20-40µM) decreased the amplitude and frequency of ICC pacemaker activity in a concentration-dependent manner. This action was blocked by guanosine 5'-[ß-thio]diphosphate [a guanosine-5'-triphosphate (GTP)-binding protein inhibitor] and by glibenclamide [an adenosine triphosphate (ATP)-sensitive K(+) channel blocker]. To study the GRe-induced signaling pathway in ICCs, the effects of 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (a guanylate cyclase inhibitor) and RP-8-CPT-cGMPS (a protein kinase G inhibitor) were examined. Both inhibitors blocked the inhibitory effect of GRe on ICC pacemaker activity. L-NG-nitroarginine methyl ester (100µM), which is a nonselective nitric oxide synthase (NOS) inhibitor, blocked the effects of GRe on ICC pacemaker activity and GRe-stimulated cGMP production in ICCs. CONCLUSION: In cultured murine ICCs, GRe inhibits the pacemaker activity of ICCs via the ATP-sensitive potassium (K(+)) channel and the cGMP/NO-dependent pathway. Ginsenoside Re may be a basis for developing novel spasmolytic agents to prevent or alleviate GI motility dysfunction.

Effects of traditional Chinese herbal medicine San-Huang-Xie-Xin-Tang on gastrointestinal motility in mice.

AIM: To investigate the effects of San-Huang-Xie-Xin-Tang (SHXXT), a herbal product used in traditional Chinese medicine, on gastrointestinal (GI) motility in mice. METHODS: The in vivo effects of SHXXT on GI motility were investigated by measuring the intestinal transit rates (ITRs) using Evans blue in normal mice and in mice with experimentally induced GI motility dysfunction (GMD). RESULTS: In normal ICR mice, ITRs were significantly and dose-dependently increased by SHXXT (0.1-1 g/kg). GMD was induced by injecting acetic acid or streptozotocin intraperitoneally. The ITRs of GMD mice were significantly reduced compared to normal mice, and these reductions were significantly and dose-dependently inhibited by SHXXT (0.1-1 g/kg). CONCLUSION: These results suggest that SHXXT is a novel candidate for the development of a prokinetic agent that may prevent or alleviate GMD.

Highly heterogeneous soil bacterial communities around Terra Nova Bay of Northern Victoria Land, Antarctica.

Given the diminished role of biotic interactions in soils of continental Antarctica, abiotic factors are believed to play a dominant role in structuring of microbial communities. However, many ice-free regions remain unexplored, and it is unclear which environmental gradients are primarily responsible for the variations among bacterial communities. In this study, we investigated the soil bacterial community around Terra Nova Bay of Victoria Land by pyrosequencing and determined which environmental variables govern the bacterial community structure at the local scale. Six bacterial phyla, Actinobacteria, Proteobacteria, Acidobacteria, Chloroflexi, Cyanobacteria, and Bacteroidetes, were dominant, but their relative abundance varied greatly across locations. Bacterial community structures were affected little by spatial distance, but structured more strongly by site, which was in accordance with the soil physicochemical compositions. At both the phylum and species levels, bacterial community structure was explained primarily by pH and water content, while certain earth elements and trace metals also played important roles in shaping community variation. The higher heterogeneity of the bacterial community structure found at this site indicates how soil bacterial communities have adapted to different compositions of edaphic variables under extreme environmental conditions. Taken together, these findings greatly advance our understanding of the adaption of soil bacterial populations to this harsh environment.