Isolation of key methanogens for global methane emission from rice paddy fields: a novel isolate affiliated with the clone cluster rice cluster I

Despite the fact that rice paddy fields (RPFs) are contributing 10 to 25% of global methane emissions, the organisms responsible for methane production in RPFs have remained uncultivated and thus uncharacterized. Here we report the isolation of a methanogen (strain SANAE) belonging to an abundant and ubiquitous group of methanogens called rice cluster I (RC-I) previously identified as an ecologically important microbial component via culture-independent analyses. To enrich the RC-I methanogens from rice paddy samples, we attempted to mimic the in situ conditions of RC-I on the basis of the idea that methanogens in such ecosystems should thrive by receiving low concentrations of substrate (H(2)) continuously provided by heterotrophic H(2)-producing bacteria. For this purpose, we developed a coculture method using an indirect substrate (propionate) in defined medium and a propionate-oxidizing, H(2)-producing syntroph, Syntrophobacter fumaroxidans, as the H(2) supplier. By doing so, we significantly enriched the RC-I methanogens and eventually obtained a methanogen within the RC-I group in pure culture. This is the first report on the isolation of a methanogen within RC-I.     

Screening of ACE-inhibitory peptides from a random peptide-displayed phage library using ACE-coupled liposomes

Angiotensin I converting enzyme (ACE)-inhibitory peptides were screened from a random peptide-displayed phage library using ACE-coupled liposomes. Among four kinds of inhibitory peptides selected by biopanning with two different elution strategies, a peptide (LSTLRSFCA) showed the highest inhibitory activity with an IC(50) value of 3microM. By measuring inhibitory activities of fragments of the peptide, it was found that the RSFCA region was a functional site to inhibit strongly the ACE catalytic activity, and particularly both Arg and Cys residues were essential for the strong inhibitory activity. The inhibitory activity of RRFCA was slightly increased, while that of the RSFRA, in which the Cys residue was replaced by Arg, was decreased to greater extent in comparison with the inhibitory activity of RSFCA. Taking into account the results obtained from the SPOT analysis, it was suggested that the Arg and Phe residues in RSFCA were important for a specific interaction with ACE, and the Cys residue inhibited the ACE activity. The cystein-based ACE-inhibitory peptides have not been isolated from processed food materials. These findings suggested that the biopanning method utilizing protein-coupled liposomes and random peptide libraries might have a possibility to screen new functional peptides that are not found in processed food materials.     

The effect of calcium ion on the biodegradation of octylphenol polyethoxylates,and the antiandrogenic activity of their biodegradates

Because limes have been used as important fertilizers to neutralize acidified farmland in Japan, our interest in this study was focused on the effect of calcium ion on the biodegradation of octylphenol polyethoxylates (OPEOn) by a pure culture of Pseudomonas putida S5 isolated from a rice paddy field in Japan. In the presence of calcium ion, P. putida S5 accelerated the formation of octylphenol oligoethoxy carboxylates (OPECn) rather than that of octylphenol oligoethoxylates under an aerobic condition, indicating that more soluble biodegradates with terminal carboxyl group may liquate out easily to surface and ground water rather than more hydrophobic biodegradates with shorter ethylene oxide residues. Therefore, the androgen receptor (AR) activity of their degradation products was characterized using an in vitro reporter gene assay. As ethylene oxide chain length decreased, the biodegradates, OPEOn (n < 3), increased their AR antagonist activity. However, OPECn (n < 3) were unable to determine their AR activity because of their cytotoxicity in our reporter gene assay system.     

The novel cargo Alcadein induces vesicle association of kinesin-1 motor components and activates axonal transport

Alcadeinalpha (Alcalpha) is an evolutionarily conserved type I membrane protein expressed in neurons. We show here that Alcalpha strongly associates with kinesin light chain (K(D) approximately 4-8x10(-9) M) through a novel tryptophan- and aspartic acid-containing sequence. Alcalpha can induce kinesin-1 association with vesicles and functions as a novel cargo in axonal anterograde transport. JNK-interacting protein 1 (JIP1), an adaptor protein for kinesin-1, perturbs the transport of Alcalpha, and the kinesin-1 motor complex dissociates from Alcalpha-containing vesicles in a JIP1 concentration-dependent manner. Alcalpha-containing vesicles were transported with a velocity different from that of amyloid beta-protein precursor (APP)-containing vesicles, which are transported by the same kinesin-1 motor. Alcalpha- and APP-containing vesicles comprised mostly separate populations in axons in vivo. Interactions of Alcalpha with kinesin-1 blocked transport of APP-containing vesicles and increased beta-amyloid generation. Inappropriate interactions of Alc- and APP-containing vesicles with kinesin-1 may promote aberrant APP metabolism in Alzheimer's disease.     

Bimodal clock gene expression in mouse suprachiasmatic nucleus and peripheral tissues under a 7-hour light and 5-hour dark schedule

Using the mPer1::luc real-time monitoring technique, the authors observed the bimodal patterns of mPer1 bioluminescence on each side of the SCN, in parallel with maintaining synchronization between the left and right sides of the SCN under an artificial light:dark:light:dark (LDLD) 7:5:7:5 condition. In situ hybridization analysis of mPer1 and mBmal1 mRNA distribution in the SCN showed that in 1 photophase (morning photophase; M) of LDLD, the mPer1 level in the ventrolateral-like (VL-like) subdivision of the SCN was higher than that in the dorsomedial-like (DM-like) subdivision, and this regional distribution pattern was reversed in another photophase (evening photophase; E). In contrast, the mBmal1 level was higher in the DM-like subdivision than in the VL-like subdivision in the M phase, and this distribution changed in the E phase. The prokineticin 2 (PK2) mRNA that encodes an SCN output molecule that is thought to transmit the circadian locomotor rhythms was reduced in both the DM-like and VL-like SCN and did not clearly correlate with the activity under the LDLD condition. The expression of mPer1 and mPer2 in the liver was clearly bimodal, whereas the expressions of other clock genes were not synchronized to the LDLD condition. These results may provide important insights into the mechanism underlying the splitting or bimodal rhythms that may in turn facilitate the understanding of the ability to measure the seasonal day length in mammals.     

Intrinsic chiral domains enantioselectively segregated from twisted nematic cells of bent-core mesogens

Enantioselective segregation has been attained in the Bx phase of a novel substituted oxadiazole achiral banana-shaped liquid crystal (LC) without introducing any chiral species. This bent-core molecule exhibits LC polymorphism; the higher temperature nematic (N) phase and the lower temperature banana smectic phase (Bx phase), in which spontaneous chiral segregation with (+) and (-) chiral domains occurs with equal probabilities. In twisted cell geometries, extrinsically induced twisted N structures are formed and result in intrinsically chiral conglomerate when the temperature is decreased from N to Bx. The observed optical activity in homochiral Bx phase is comparable to those theoretically predicted and is proportional to the cell thickness.     

Peculiar protein-protein interactions of the novel endoplasmic reticulum membrane protein Rcr1 and ubiquitin ligase Rsp5

Overproduction of the ER membrane protein Rcr1 makes Saccharomyces cerevisiae resistant to Congo red by reducing the chitin content through a unknown mechanism. By both co-immunoprecipitation and yeast two-hybrid experiments, specific interaction between Rcr1 and the ubiquitin ligase Rsp5 was found. This binding was largely mediated by a singular VPEY sequence in Rcr1 in addition to PPSY, the consensus ligand motif of the WW domains. Mutant analysis indicated that Rsp5 and other Rcr1-interacting proteins discovered in the current screen were not engaged in Congo red resistance.     

Association between prostaglandin E2 receptor gene and essential hypertension

BACKGROUND: Essential hypertension (EH) is a complex multifactorial polygenic disorder that is thought to result from an interaction between an individual's genetic makeup and various environmental factors. In the kidney, prostaglandins (PGs) are important mediators of vascular tone and salt and water homeostasis, and are involved in the mediation and/or modulation of hormonal action. In previous studies, mice deficient in the prostaglandin E2 (PGE(2)) EP2 receptor had resting systolic blood pressure (BP) that was significantly lower than that of wild-type controls. The BP of those mice increased when they were put on a high-salt diet, suggesting that the EP2 receptor is involved in sodium handling by the kidney. In the present study, we investigated the association between EH and nucleotide polymorphisms in the gene encoding the prostaglandin E2 receptor subtype EP2 (PTGER2). METHODS: We selected three single-nucleotide polymorphisms (SNP) in the human PTGER2 gene (rs1254601, rs2075797, and rs17197), and we performed a genetic association study of 266 EH patients and 253 age-matched normotensive (NT) controls. RESULTS: There was no significant difference in overall distribution of genotypes or alleles of any of the SNP between the EH and NT groups. However, among men, the A/A type of the SNP rs17197 (rs17197, A/G in 3'UTR) was significantly more frequent in EH subjects than in NT subjects (P=0.041). CONCLUSION: The present findings suggest that rs17197 is useful as a genetic marker of EH in men.     

Characterization and immobilization of liposome-bound cellulase for hydrolysis of insoluble cellulose

The liposome-bound cellulase was prepared by covalently coupling cellulase with the enzyme-free liposomes bearing aldehyde groups so that cellulase was located solely on the outer membrane of liposomes. The modified cellulase possessed the higher activity efficiency and lipid-based specific activity than the cellulase-containing liposomes reported previously. The enzyme-free liposomes bearing aldehyde groups were covalently immobilized with the chitosan gel beads and the free cellulase was coupled with the treated gel beads to prepare the immobilized liposome-bound cellulase. The activity efficiency of the immobilized liposome-bound cellulase was much higher than that of the conventionally immobilized cellulase. The results on reusability of the immobilized liposome-bound cellulase in the hydrolysis of either soluble or insoluble cellulose showed that the immobilized liposome-bound cellulase had the higher remaining cellulase activity and reusability than the conventionally immobilized cellulase for the hydrolysis of either type of cellulose. The liposomal membrane was suggested to be efficient in maintaining the cellulase activity during the hydrolysis.