Recently, high-throughput screening (HTS) has become the mainstream technique for drug discovery. Compounds that are synthesized by combinatorial chemistry might be more suitable than natural products to apply to HTS, because the purification procedure is a drawback of using natural products. Nevertheless, natural products remain an extremely important source of drugs. To overcome the demerits of natural products, we are constructing the RIKEN Natural Products Depository (NPDepo) that is focused primarily on microbial metabolites. In this review, I describe (i) engineering pathways for biosynthetic gene clusters of microbial metabolites, (ii) construction of fraction libraries of microbial metabolites, and (iii) the development of a new screening system using a chemical array and a protein library produced by GLORIA.

View full abstract

Glycan-binding proteins are categorized into two groups, lectins and sulfated glycosaminoglycan-binding proteins. SUEL-related lectins are members of a superfamily of proteins containing a carbohydrate-recognition domain (CRD), which is structurally similar to sea urchin egg lectin (SUEL). Here I review the structure and function of this family of proteins.

View full abstract

Termites play a key role in the global carbon cycle as decomposers. Their ability to thrive solely on dead plant matter is chiefly attributable to the activities of gut microbes, which comprise protists, bacteria, and archaea. Although the majority of the gut microbes are as yet unculturable, molecular analyses have gradually been revealing their diversity and symbiotic mechanisms. Culture-independent studies indicate that a single termite species harbors several hundred species of gut microbes unique to termites, and that the microbiota is consistent within a host termite species. To elucidate the functions of these unculturable symbionts, environmental genomics has recently been applied. Particularly, single-species-targeting metagenomics has provided a breakthrough in the understanding of symbiotic roles, such as the nitrogen fixation, of uncultured, individual microbial species. A combination of single-species-targeting metagenomics, conventional metagenomics, and metatranscriptomics should be a powerful tool to dissect this complex, multi-layered symbiotic system.

View full abstract

Twelve novel naphthoquinone esters containing cyclopentyl and cyclohexyl substituents at C-2′ of the propyl chain were synthesized by starting from 1-hydroxy-2-naphthoic acid via alkylation with cyclopentyl ester and cyclohexyl ester. They were evaluated for cytotoxicity against three cancer cell lines (human epidermoid carcinoma (KB), human cervical carcinoma (HeLa), and human hepatocellular carcinoma (HepG₂)). In comparison to naphthoquinone esters with the 2′,2′-dimethyl group, the naphthoquinones with a 2′-cyclopentyl substituent showed stronger activity than those with a 2′-cyclohexyl substituent, but less than that with the 2′,2′-dimethyl group. This work provides new information about the effect of 2′-position substituents on the cytotoxicity of naphthoquinone ester analogues.

View full abstract

The conidium of the entomopathogenic fungus, Nomuraea rileyi, has been found to germinate rapidly in the presence of a host insect-derived extract. This extract therefore appears to contain an important factor involved in host recognition by N. rileyi, although the substance (germination-accelerating factor, GAF) responsible for such unique germination behavior has yet to be identified. Our previous study was extended to the isolation of GAF from pupae of the silkworm, a host insect of N. rileyi. This present work subjects GAF to a structural analysis. The chemical structure of GAF is characterized as 2S-amino-tetradeca-4-ene-1,3R-diol (D-erythro-C₁₄-sphingosine) based on spectroscopic data. An examination of the structure-activity relationship shows that the activity of D-erythro-C₁₄-sphingosine was superior to that of sphingosines with shorter and longer carbon chains. It is suggested that the molecular species with a 14-carbon chain of a sphingosine is important for host recognition.

View full abstract

An aroma concentrate of the mat rush (igusa) was prepared by combining solvent extraction with the solvent-assisted flavor evaporation (SAFE) technique. An aroma extract dilution analysis (AEDA) applied to the volatile fraction revealed 51 odor-active peaks with FD factors between 4³ and 4⁷. Among the perceived odorants, twelve peaks with the higher FD factors (≥4⁶) were proved to be the most important components of the characteristic aroma in mat rush. Eleven odorants were identified or tentatively identified from the twelve peaks as methional, (E,Z)-2,6-nonadienal, (E)-2-nonenal, (E,E)-2,4-nonadienal, (E,E,Z)-2,4,6-nonatrienal, trans-4,5-epoxy-(E)-2-decenal, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 3-hydroxy-4,5-dimethyl-2(5H)-furanone, isovaleric acid, methyl anthranirate, and vanillin. The FD factors of the odor-active peaks in dried mat rush were observed to be much higher than those in raw mat rush. This finding suggests that the drying process during manufacturing of the mat rush is one of the most important factors for the formation of the characteristic mat rush aroma.

View full abstract

A total synthesis of annonacin (1) was accomplished by using versatile chiral building block 2 for synthesizing the mono-tetrahydrofuran (THF) annonaceous acetogenins.

View full abstract

Two cyclic peptides, PF1171A (1) and PF1171C (2), were isolated from okara that had been fermented with unidentified ascomycete OK-128. Their absolute configurations were determined by Marfey’s method. These peptides showed paralytic activity against silkworms.

View full abstract

Woody materials are generally resistant to enzymatic saccharification unless they undergo harsh fiber disrupting pre-treatments such as steam explosion. In this study, enzymatic hydrolysis of steam-exploded hardwood was investigated using various conditions and commercial cellulase preparations. Hydrolysis times were kept below 24 h in order to approach industrially realistic conditions. The optimal conditions for enzymatic hydrolysis were found to be 55 °C and a pH of about 4.5. During enzymatic hydrolysis, acetate was released from the hemicellulose fraction. Increasing the dry matter concentration had a negative effect on glucose yields. Using fermentors with pH control, 66% of the cellulose in steam-exploded hardwood could be hydrolyzed to glucose within 12 h using an enzyme dose of 25 filter paper units (FPU)/g of dry matter. For 24 h hydrolysis maximum cellulose saccharification (71%) was observed at 25 FPU/g, and increasing the enzyme dose further did not increase the sugar yield.

View full abstract

A systematic strategy for producing biologically active full-length human peroxisome proliferator-activated receptor-γ (PPAR-γ) was developed. PPAR-γ was expressed as inclusion bodies in Terrific Broth (TB) ensuring stable pH, better growth conditions, and 4-fold higher cell yield as compared to Luria Broth (LB). Purification was performed by a combination of immobilized metal-ion affinity chromatography (IMAC) and size exclusion chromatography (SEC), yielding 176 mg of PPAR-γ of over 90% purity per liter of TB. A simplified refolding setup, capable of gradual buffer exchange and continuous protein feeding, was used to refold the denatured PPAR-γ with approximately 66% yield. Correct refolding of the denatured PPAR-γ was assessed with non-denaturing gels and SEC. The refolded PPAR-γ displayed its ligand binding ability for rosiglitazone at K_d=250±6 nM as determinated by SEC-HPLC assay. In addition, DNA binding activity of the refolded PPAR-γ was demonstrated by electrophoretic mobility shift assay (EMSA) using a PPRE motif. The integrity of PPAR-γ was confirmed by mass spectrometry. Our results indicate the feasibility of using these strategies to produce biologically active full-length PPAR-γ in E. coli BL21 (DE3).

View full abstract

Hypoxia is one of the inevitable circumstances of various tumors. It controls various levels of regulation in tumor progression and results in tumor resistance to radiotherapy and chemotherapy. Here we investigated a synthetic TPZ derivative, N-ethoxymethyl-3-amino-1,2,4-benzotriazine-1,4-dioxide (XQ2), a novel compound that induced anti-cancer effects both in normoxia and in hypoxia, cell proliferation assay found that XQ2 exhibited a potent inhibitory effect on the tested cancer cell lines both in normoxia and in hypoxia. Flow cytometry and western blot studies indicated that XQ2 induces G2/M arrest and a caspase-dependent apoptosis in A549 cells. Additionally, intracellular reactive oxygen species (ROS) appear to play a key role in the anticancer effect of XQ2 in hypoxia. Taken together, our data suggest that XQ2 exerted anticancer action by suppressing the ROS level and triggering cell-cycle arrest and the caspase-dependent pathway, which is associated with apoptosis.

View full abstract

Formulations containing engkabang fat and engkabang fat esters, F10 and E15 respectively were prepared using a high-shear homogenizer, followed by a high-pressure homogenizer. Both formulations were stable at room temperature, at 45 °C, and after undergoing freeze-thaw cycles. The particle sizes of F10 and E15 after high pressure were 115.75 nm and 148.41 nm respectively. The zeta potentials of F10 and E15 were −36.4 mV and −48.8 mV respectively, while, the pH values of F10 and E15 were 5.59 and 5.81 respectively. The rheology of F10 and E15 showed thixotropy and pseudoplastic behavior respectively. There were no bacteria or fungal growths in the samples. The short-term moisturizing effect on 20 subjects analyzed by analysis of variance (ANOVA), gave p-values of 7.35×10⁻¹² and 2.77×10⁻¹⁵ for F10 and E15 respectively. The hydration of the skins increased after application of F10 and E15 with p-value below 0.05.

View full abstract

Recently, we obtained two L-carnitine dehydrogenases (CDHs) from soil isolates, Rhizobium sp. (Rs-CDH) and Xanthomonas translucens (Xt-CDH). The respective molecular masses of Rs-CDH and Xt-CDH were approximately 50 kDa and 37 kDa. In this study, the genes encoding both enzymes were cloned. Their primary structures exhibited high identities with those of 3-hydroxyacyl-CoA dehydrogenases. In addition, Rs-CDH had a 180-residue long extra sequence in its C-terminal region. Except for the initial 20 residues, the extra sequence exhibited similarity to thioesterase. The activity of Rs-CDH was affected only slightly by deletion of thioesterase domain, but it was eliminated by the deletion of the whole C-terminal extra sequence. A further deletion experiment indicated that the region of Ala330–Pro335 of Rs-CDH has important functions in catalytic activity. Moreover, based on the deletion experiment on Xt-CDH, the five-residue tail is considered to have a function similar to Ala330–Pro335 of Rs-CDH.

View full abstract

Hydroxyurea (HU, NH₂CONHOH), or hydroxycarbamide, is a hydroxamic acid derivative used as a drug for anti-neoplasm and sickle-cell disease. In this study, HU was found to have antioxidant activities against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radicals and dose-dependent inhibitory activities against monoamine oxidase (MAO)-A, MAO-B, and semicarbazide-sensitive amine oxidase (SSAO) as compared to controls of clorgyline, deprenyl, and semicarbazide respectively. HU showed mixed-type, competitive-type, and competitive-type inhibition, respectively, with respect to substrates of MAO-A, MAO-B, and SSAO with apparent inhibition constants (Ki) of 19.46, 5.38, and 1.84 μM.

View full abstract

Analysis of fucosylated glycoconjugates in rat prostate by lectin blotting with Aleuria aurantia lectin revealed that the tissue contained characteristic low-molecular weight species (prostatic fucosylated glycoconjugates, PFGs). PFGs were detected almost exclusively in the ventral lobe of the prostate among rat tissues examined, and showed an apparent positive androgen dependency, that is, the content of PFGs decreased after castration and then slowly recovered upon androgen replacement. PFGs were resistant to solubilization with Triton X-100, but could be extracted with chloroform-methanol. Treatment of the crude PFG preparation with endoglycoceramidase resulted in the complete disappearance of PFGs. PFGs were also susceptible to α1,3/4-L-fucosidase but not to peptide-N-glycosidase F. Prostate-specific expression of PFGs was confirmed by thin layer chromatography and subsequent blot analysis. These results suggest that PFGs are fucosylated glycosphingolipid species specifically expressed in the rat ventral prostate, and that PFG expression is associated with some androgen-regulated processes in the tissue.

View full abstract

To clarify the effects of O₂ concentration (cO₂) on antioxidant gene expression in human hepatocytes, mRNA expression of HepG2 cells cultured at 1, 3, and 5% cO₂ and atmospheric gas-phase, was measured. The expression of some genes fluctuated depending on the cO₂ in the incubator. This indicates that cO₂ is a critically important factor in the investigation of human biological mechanisms.

View full abstract

The effects of nanosecond pulsed electric fields (nsPEFs) on medaka eggs were examined. Although embryogenesis was not affected by nsPEF treatment alone, significant harmful effects were observed when the eggs were treated with nsPEFs in the presence of cycloheximide in the outer solution. Nanosecond PEF treatment affected the permeability of both the egg envelope (chorion) and the cell membrane, which resulted in intracellular incorporation of cycloheximide.

View full abstract

Sulfoquinovosyldiacylglycerol (SQDG) contents in conifer leaves and their fatty acid (FA) compositions were determined. The SQDG content was 16–36 mg/100 g, and was high in Picea glehnii. Palmitic and α-linolenic acid were the usually predominant FAs. In Picea, the proportion of α-linolenic acid was low, and those of oleic and linoleic acid were high. The essential oil residues of Abies sachalinensis leaves were found to be a potential source of SQDG material.

View full abstract

Cloning of pceA, the gene of tetrachloroethene (PCE)-reductive dehalogenase, was undertaken from environmental DNA. Two genes were amplified using PCR primer deduced from pceA. Functional expression of these genes was unsuccessful in Escherichia coli, but PceA1 synthesized in vitro was enzymatically active. In recombinant E. coli, PceA1 formed a complex with host DnaK and caused filamentous growth.

View full abstract

Matriptase is a type-II transmembrane serine protease abundantly expressed in polarized epithelia. The ectodomain of matriptase is released from the cell surface. In the present study, we found that the post-translational cleavage between Gly149 and Ser150 and the existence of catalytic domain are critical for the ectodomain release of matriptase in stable transfection experiments using the polarized Madin–Darby canine kidney epithelial cell line.

View full abstract

After modification with monomethoxyl-poly(ethylene glycol)-5000, a recombinant intracellular uricase from Bacillus fastidiosus ATCC 29604 showed residual activity of about 65%, a thermo-inactivation half-life >85 h, a circulating half-life about 20 h in rats in vivo, consistent effects of common cations, and consistent optima for reaction temperature and pH. Thus, this uricase can be formulated via modification with monomethoxyl-poly(ethylene glycol).

View full abstract

SUMO-interacting motifs (SIMs) play a central role in the fate of SUMO-modified proteins. Here we report a real-time SUMO-binding assay. It can be applied to the identification of SIMs and to screening for the identification of novel SUMO-binding proteins. Using this assay, we investigated the SIMs in SETDB1 and MCAF1 to gain insight into the assembly of SETDB1-MCAF1-mediated gene silencing.

View full abstract

Bacillus subtilis IolT is the major myo-inositol transporter for growth, while IolF is a minor one unable to support growth. We found that either IolT or IolF was sufficient for moderate growth using D-chiro-inositol. Conversely to IolT, IolF transported D-chiro-inositol more preferentially than myo-inositol. These results indicate that IolT and IolF are different in substrate specificity.

View full abstract

We constructed two series of Gateway binary vectors, pGWBs and R4pGWBs, possessing the bialaphos resistance gene (bar) as a selection marker for plant transformation. The reporters and tags employed in this system are sGFP, GUS, LUC, EYFP, ECFP, G3GFP, mRFP, TagRFP, 6xHis, FLAG, 3xHA, 4xMyc, 10xMyc, GST, T7 and TAP. Selection of Arabidopsis transformants with BASTA^® was successfully carried out using both plate-grown and soil-grown seedlings. Transformed rice calli and suspension-cultured tobacco cells were selected on plates containing BASTA^® or glufosinate-ammonium. These vectors are compatible with existing pGWB and R4pGWB vectors carrying kanamycin and hygromycin B resistance.

View full abstract

The root cortex of Paeonia suffruticosa Andrews (PSA), also known as Moutan Cortex, is known to have anti-allergic and anti-inflammatory properties. This study investigates the effect and mechanism of PSA by in vivo and in vitro methods. Treatings the root cortex from PSA with up to 0.4 mg/ml of an ethanol extract showed no cytotoxicity in human mast cells. The ethanol extract of PSA (200 mg/kg) significantly inhibited the passive cutaneous anaphylaxis reaction in vivo, and suppressed the release of histamine from rat peritoneal mast cells induced by compound 48/80. It was also found that PSA decreased the expressions of TNF-alpha and IL-6 in PMA- and A23187-stimulated HMC-1 cells. The results show the inactivation of IkappaB-alpha and NF-kappaB, as well as suppression of the phosphorylation of extracellular signal-regulated kinase (ERK). Our findings therefore suggest that PSA could be promising for anti-allergic inflammation by inhibiting the NF-kappaB/IkappaB-alpha signaling pathway and the phosphorylation of ERK.

View full abstract

It became possible to produce high-quality and bio-functional wheat/rice bread and wheat/rice noodles by blending, pre-germinated and cooked brown rice of a super-hard cultivar with wheat flour. Super-hard rice (SHR) is not suitable for table rice because of its low palatability. Nevertheless, it was found to be suitable as a blending material for bread-making or noodle-making due to its hard texture and high content of resistant starch. We developed a novel rapid germination method to improve the quality and to save the time needed for germination. By blending pre-germinated and cooked SHR (30% w/w on a dry basis) as a rice gel with wheat flour (70% w/w on a dry basis), the bread became very soft and any hardening after bread-making was markedly retarded. Similarly, blending pre-germinated and cooked SHR as cooked a rice gel with wheat flour gave high-quality noodles with a similar texture to that of durum semolina noodles. The resistant starch of the SHR-blended bread and noodles was also markedly increased. White waxy rice (9%) soaked and cooked with the pre-germinated brown rice of SHR (21%) produced a rice gel that was very useful as a material for bread-making and noodle-making by blending with wheat flour (70%) to prepare soft, tasty and bio-functional wheat/rice bread and wheat/rice noodles.

View full abstract

Infection with Helicobacter pylori (H. pylori) can induce gastric disorders, and though its presence cannot explain disease pathogenesis and does not have associations with other factors, it is well known that H. pylori infection causes stomach inflammation following oxidative stress. We examined the suppressive effects of a leaf extract of Wasabia japonica on H. pylori infection and on stress loading in Mongolian gerbils. Following oral administration of wasabi extract of 50 and 200 mg/kg B.W./d for 10 d, the animals were exposed to restraint stress for 90 and 270 min. As for the results, the level of 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) in the stomach and oxidative DNA damage in peripheral erythrocytes at 270 min significantly increased. That elevation was significantly suppressed by the addition of the leaf extract. We concluded that the simultaneous loading of H. pylori infection and physical stress loading might induce oxidative DNA damage additively, while a leaf extract attenuated this DNA damage in the stomach as well as the peripheral erythrocytes.

View full abstract

Nine essential oils were examined for antimicrobial activity against reference and clinical strains of Salmonella Enteritidis. Based on the size of the inhibition zone and the minimal inhibitory concentration, basil oil had the strongest antimicrobial activity against all the tested bacteria, and S. Enteritidis SE3 was the most sensitive strain to all the tested oils. Gas chromatography/mass spectrometry analysis revealed that the major constituents of the oil were linalool (64.35%), 1,8-cineole (12.28%), eugenol (3.21%), germacrene D (2.07%), α-terpineol (1.64%), and ρ-cymene (1.03%). When applied in nham, a fermented pork sausage, experimentally inoculated with S. Enteritidis SE3 and stored at 4 °C, basil oil inhibited the bacterium in a dose-dependent fashion. Basil oil at a concentration of 50 ppm reduced the number of bacteria in the food from 5 to 2log cfu/g after storage for 3 d. An unmeasurable level of the bacterium in the food was observed at days 2 and 3 of storage when 100 and 150 ppm of basil oil was used, respectively. Sensory evaluation suggested that the addition of 100 but not of 150 ppm to nham would be acceptable to consumers. The results from this study confirm the potential use of basil oil as an antimicrobial agent to control S. Enteritidis in food.

View full abstract

The intestinal absorption of chondroitin sulfate (CS) and its hydrolysate, particularly the disaccharides (Di-CS), was investigated by using human intestinal epithelial Caco-2 cell monolayers. Although the transepithelial transport of CS was not detectable, dose- and time-dependent transport of Di-CS was observed. The transport of Di-CS was proved to be energy-independent and its permeability increased inversely with the transepithelial electrical resistance (TER) value of the Caco-2 cell monolayers. The transport rate for Di-CS was also increased by treating the cell monolayers with such tight junction-opening agents as interferon-γ. These results suggest that Di-CS permeated across the Caco-2 cell monolayers mainly via the paracellular pathway. The permeability of Caco-2 cell monolayers to authentic chondroitin 4-sulfate disaccharides (Di-4S), chondroitin 6-sulfate disaccharides (Di-6S) and chondroitin 0-sulfate disaccharides (Di-0S) was almost same, suggesting that sulfation did not affect the transport rate of Di-CS.

View full abstract

The relationship between insulin sensitivity and the plasma triglyceride-lowering effect induced by β-conglycinin was investigated. Male Wistar rats (19 weeks old) were fed diets containing casein, soy protein isolate, or β-conglycinin for 4 weeks. In oral glucose administration, the β-conglycinin-fed rats showed a significant decrease in the area under the glucose curve (0–60 min) as compared with the casein-fed rats. The hypoglycemic effect was significantly higher in the β-conglycinin-fed rats than in the casein-fed rats at 30 min after intraperitoneal insulin injection. The liver sterol regulatory element-binding-protein-1 mRNA expression level was significantly lower and the plasma adiponectin concentration was significantly higher in the β-conglycinin-fed rats than in the casein-fed rats. The hypotriglyceridemic effect of β-conglycinin depended on a significant decrease in the concentration of very-low-density-lipoprotein triglycerides. These results indicate that β-conglycinin increases adiponectin levels and improves glucose tolerance. The ability of β-conglycinin to lower plasma lipid levels might be due to increased insulin sensitivity of the liver.

View full abstract

A water-soluble chicken extract is popularly consumed as a traditional health food. The studies made revealed that it could increase the survival time and inhibit the increase of locomotor activity in rats loaded with food-deprived activity stress. The mechanism for this might be related to an elevation of the brain histamine level, and the active ingredient, carnosine, might contribute to this effect.

View full abstract

We examined the bioactivity of Yamato-mana (Brassica rapa L. Oleifera Group) constituent glucosinolates and found that 3-butenyl glucosinolate (gluconapin) decreased the plasma triglyceride gain induced by corn oil administration to mice. However, phenethyl glucosinolate (gluconasturtiin) had little effect. 2-Propenyl glucosinolate (sinigrin) also reduced the plasma triglyceride level, which suggests that alkenyl glucosinolates might be promising agents to prevent postprandial hypertriglyceridemia.

View full abstract

Two 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging compounds were isolated from soybean miso. They were determined to be 2,4,4′-trihydroxydeoxybenzoin and 3′-hydroxydaidzein on the basis of spectroscopic data. In the manufacturing process for soybean miso, 2,4,4′-trihydroxydeoxybenzoin appeared during culture aging, and the quantity of it increased in a time-dependent manner.

View full abstract

To identify the immunostimulants included in green tea extract, we investigated a crude tea polysaccharide related to increases in phagocytic activity using macrophage-like cells, and found that the crude tea polysaccharide from immature tea leaves included many RNAs as compared with that from mature tea leaves. Furthermore, the crude tea polysaccharide increased phagocytosis through toll-like receptor 7.

View full abstract

Considering that animals maintain energy homeostasis in response to nutrient levels, experiments were done to elucidate the temporal effects of refeeding after fasting on gene expression profiles in the rat liver. Using DNA microarray technology, we first compared gene expression profiles in the livers of rats allowed to feed for 6 h after fasting for 18 h and those in 24-h fasting rats, and found that the expression levels of energy metabolism-related genes in the two groups were different. In addition, refeeding induced upregulation of the genes encoding immunoproteasome components. Finally, immunoblot analysis confirmed changes in protein levels, suggesting that refeeding after fasting enhanced immune function.

View full abstract

2-Deoxy-scyllo-inosose (DOI) synthase participates in the biosynthesis of 2-deoxystreptamine (DOS)-containing aminoglycoside antibiotics. The enzyme is expected to be of industrial use, because it converts a sustainable resource (glucose 6-phosphate) into carbocycle (DOI), which easily aromatizes to yield catechol. In the present study, we clarified the physiological role of a non-catalytic 20 kDa protein, BtrC2, associated with DOI synthase from the butirosin-producer Bacillus circulans. Based on the results of complementation analysis using btrC2 disruptant and western analysis against catalytic 40 kDa protein (BtrC) and BtrC2, it is suggested that BtrC2 has two functions. It is involved in the vitamin B₆ biosynthesis in primary metabolism, like homologous protein (Pdx2) in Bacillus subtilis. Additionally, it takes part in butirosin biosynthesis as stabilizer of DOI synthase by forming a heterodimer with BtrC, and qualifies B. circulans for stable and constant production of butirosin for long periods.

View full abstract

A psychrophilic protease-producing bacterium, HW08, was isolated from sediment of the Yellow Sea in eastern China. On the basis of 16S rDNA sequence analysis and physiological properties, the isolate was identified as Pseudomonas lundensis. The secreted protease, named Ps5, was purified from the culture supernatant as a monomer with an apparent molecular mass of 46 kDa on SDS–PAGE. As a metalloprotease (inhibited by EDTA), the enzyme showed maximum activity at 30 °C at pH 10.4. It had no activity loss exposed at 4 °C for 60 d or under repeated freezing and thawing. Broad temperature (25–40 °C) and pH (7.0–11.0) stability was observed in the presence of 5 mm Ca²⁺. Furthermore, the enzyme was resistant to detergent additives such as non-ionic surfactants and bleaches. It showed considerable potential for industry that requires alkaline-protease.

View full abstract

Rice-paddy microbial fuel cells generate electricity from organic matter that is photosynthesized by rice plants and exudated from the roots. We examined factors that might affect cell performance, and found that cathode modification with platinum catalysts, anode position, and external load largely affected the power output.

View full abstract