Effect of Donepezil on Group II mGlu Receptor Agonist- or Antagonist-Induced Amnesia on Passive Avoidance in Mice

We examined the effect of the acetylcholinesterase (ACHE) inhibitor, donepezil hydrocloride (DONP), on group II metabotropic glutamate (mGlu) receptor agonist- or antagonist-induced amnesia in the step-through passive avoidance task in male mice. DCG-IV, a group II mGlu receptor agonist, at dose of 50 ng and LY341495, a group II mGlu receptor antagonist, at dose of 300 ng, significantly attenuated the latency on the step-through task. The subcutaneous injection of DONP at dose of 1 mg/kg 1 hour before passive avoidance performance ameliorated the amnesia induced by DCG-IV and LY341495, whereas donepezil alone did not affect task latency. The results suggest that activation of group II mGlu receptors and disinhibition of the cAMP/PKA signaling pathway (caused by group II mGlu receptor antagonist) have a negative action on step-through passive avoidance memory performance, and that group II mGlu receptors and ACh interact to modulate learning and memory function

Effects of Fipronil on Non-target Ants and Other Invertebrates in a Program for Eradication of the Argentine Ant, Linepithema humile

Pesticides are frequently used to eradicate invasive ant species, but pose ecological harm. Previous studies assessed non-target effects only in terms of the increase or decrease of abundance or species richness after pesticide applications. Positive effects of the release from pressure caused by invasive ant species have not been considered so far. To more accurately assess pesticide effects in the field, the non-target effects of pesticides should be considered separately from the positive effects of such releases. Here, we used monitoring data of ants and other invertebrates collected in a program for the eradication of the Argentine ant, Linepithema humile (Mayr), using fipronil. First, we separately assessed the effects of L. humile abundance and fipronil exposure on non-target ants and other invertebrates using generalized linear models. The abundance of L. humile and the number of pesticide treatments were negatively associated with the total number of non-target individuals and taxonomic richness. We also noted negative relationships between the number of individuals of some ant species and other invertebrate taxonomic groups. The L. humile × pesticide interaction was significant, suggesting that the abundance of L. humile affected the level of impact of pesticide treatment on non-target fauna. Second, we evaluated the dynamics of non-target ant communities for 3 years using principal response curve analyses. Non-target ant communities treated with fipronil continuously for 3 years recovered little, whereas those treated for 1 year recovered to the level of the untreated and non-invaded environment

Sesamin catechol glucuronides exert anti-inflammatory effects by suppressing IFN-β and iNOS expression through the deconjugation in macrophage-like J774.1 cells

Sesamin, a representative sesame lignan, has health-promoting activities. Sesamin is converted into catechol derivatives and further into their glucuronides or sulfates in vivo, whereas the biological activities of sesamin metabolites remain unclear. We examined the inhibitory effects of sesamin metabolites on the lipopolysaccharide (LPS)-induced NO production in mouse macrophage-like J774.1 cells and found that a mono-catechol derivative SC1, (7α,7'α,8α,8'α)-3,4-dihydroxy-3',4'-methylenedioxy-7,9':7',9-diepoxylignane, has a much higher activity than sesamin and other metabolites. The inhibitory effects of SC1 glucuronides were time-dependently enhanced, associated with the intracellular accumulation of SC1 and the methylated form. SC1 glucuronides and SC1 attenuated the expression of inducible NO synthase (iNOS) and upstream interferon-β (IFN-β) in the LPS-stimulated macrophages. The inhibitory effects of SC1 glucuronides against NO production were canceled by the β-glucuronidase inhibitor and enhanced by the catechol- O-methyltransferase inhibitor. Our results suggest that SC1 glucuronides exert the anti-inflammatory effects by inhibiting the IFN-β/iNOS signaling through macrophage-mediated deconjugation

Enhancement of Allele Discrimination by Introduction of Nucleotide Mismatches into siRNA in Allele-Specific Gene Silencing by RNAi

Allele-specific gene silencing by RNA interference (RNAi) is therapeutically useful for specifically inhibiting the expression of disease-associated alleles without suppressing the expression of corresponding wild-type alleles. To realize such allele-specific RNAi (ASP-RNAi), the design and assessment of small interfering RNA (siRNA) duplexes conferring ASP-RNAi is vital; however, it is also difficult. In a previous study, we developed an assay system to assess ASP-RNAi with mutant and wild-type reporter alleles encoding the Photinus and Renilla luciferase genes. In line with experiments using the system, we realized that it is necessary and important to enhance allele discrimination between mutant and corresponding wild-type alleles. Here, we describe the improvement of ASP-RNAi against mutant alleles carrying single nucleotide variations by introducing base substitutions into siRNA sequences, where original variations are present in the central position. Artificially mismatched siRNAs or short-hairpin RNAs (shRNAs) against mutant alleles of the human Prion Protein (PRNP) gene, which appear to be associated with susceptibility to prion diseases, were examined using this assessment system. The data indicates that introduction of a one-base mismatch into the siRNAs and shRNAs was able to enhance discrimination between the mutant and wild-type alleles. Interestingly, the introduced mismatches that conferred marked improvement in ASP-RNAi, appeared to be largely present in the guide siRNA elements, corresponding to the ‘seed region’ of microRNAs. Due to the essential role of the ‘seed region’ of microRNAs in their association with target RNAs, it is conceivable that disruption of the base-pairing interactions in the corresponding seed region, as well as the central position (involved in cleavage of target RNAs), of guide siRNA elements could influence allele discrimination. In addition, we also suggest that nucleotide mismatches at the 3′-ends of sense-strand siRNA elements, which possibly increase the assembly of antisense-strand (guide) siRNAs into RNA-induced silencing complexes (RISCs), may enhance ASP-RNAi in the case of inert siRNA duplexes. Therefore, the data presented here suggest that structural modification of functional portions of an siRNA duplex by base substitution could greatly influence allele discrimination and gene silencing, thereby contributing to enhancement of ASP-RNAi

A plastidial sodium-dependent pyruvate transporter (vol 476, pg 472, 2011)

Furumoto T, Yamaguchi T, Ohshima-Ichie Y, et al. A plastidial sodium-dependent pyruvate transporter (vol 476, pg 472, 2011). Nature. 2011;478(7368):274

Registration error of the liver CT using deformable image registration of MIM Maestro and Velocity AI

BackgroundUnderstanding the irradiated area and dose correctly is important for the reirradiation of organs that deform after irradiation, such as the liver. We investigated the spatial registration error using the deformable image registration (DIR) software products MIM Maestro (MIM) and Velocity AI (Velocity).MethodsImage registration of pretreatment computed tomography (CT) and posttreatment CT was performed in 24 patients with liver tumors. All the patients received proton beam therapy, and the follow-up period was 4–14 (median: 10) months. We performed DIR of the pretreatment CT and compared it with that of the posttreatment CT by calculating the dislocation of metallic markers (implanted close to the tumors).ResultsThe fiducial registration error was comparable in both products: 0.4–32.9 (9.3 ± 9.9) mm for MIM and 0.5–38.6 (11.0 ± 10.0) mm for Velocity, and correlated with the tumor diameter for MIM (r = 0.69, P = 0.002) and for Velocity (r = 0.68, P = 0.0003). Regarding the enhancement effect, the fiducial registration error was 1.0–24.9 (7.4 ± 7.7) mm for MIM and 0.3–29.6 (8.9 ± 7.2) mm for Velocity, which is shorter than that of plain CT (P = 0.04, for both).ConclusionsThe DIR performance of both MIM and Velocity is comparable with regard to the liver. The fiducial registration error of DIR depends on the tumor diameter. Furthermore, contrast-enhanced CT improves the accuracy of both MIM and Velocity

Genetic Determinants of Phosphate Response in Drosophila

Phosphate is required for many important cellular processes and having too little phosphate or too much can cause disease and reduce life span in humans. However, the mechanisms underlying homeostatic control of extracellular phosphate levels and cellular effects of phosphate are poorly understood. Here, we establish Drosophila melanogaster as a model system for the study of phosphate effects. We found that Drosophila larval development depends on the availability of phosphate in the medium. Conversely, life span is reduced when adult flies are cultured on high phosphate medium or when hemolymph phosphate is increased in flies with impaired Malpighian tubules. In addition, RNAi-mediated inhibition of MAPK-signaling by knockdown of Ras85D, phl/D-Raf or Dsor1/MEK affects larval development, adult life span and hemolymph phosphate, suggesting that some in vivo effects involve activation of this signaling pathway by phosphate. To identify novel genetic determinants of phosphate responses, we used Drosophila hemocyte-like cultured cells (S2R+) to perform a genome-wide RNAi screen using MAPK activation as the readout. We identified a number of candidate genes potentially important for the cellular response to phosphate. Evaluation of 51 genes in live flies revealed some that affect larval development, adult life span and hemolymph phosphate levels

Roles of Major Facilitator Superfamily Transporters in Phosphate Response in Drosophila

The major facilitator superfamily (MFS) transporter Pho84 and the type III transporter Pho89 are responsible for metabolic effects of inorganic phosphate in yeast. While the Pho89 ortholog Pit1 was also shown to be involved in phosphate-activated MAPK in mammalian cells, it is currently unknown, whether orthologs of Pho84 have a role in phosphate-sensing in metazoan species. We show here that the activation of MAPK by phosphate observed in mammals is conserved in Drosophila cells, and used this assay to characterize the roles of putative phosphate transporters. Surprisingly, while we found that RNAi-mediated knockdown of the fly Pho89 ortholog dPit had little effect on the activation of MAPK in Drosophila S2R+ cells by phosphate, two Pho84/SLC17A1–9 MFS orthologs (MFS10 and MFS13) specifically inhibited this response. Further, using a Xenopus oocyte assay, we show that MSF13 mediates uptake of [³³P]-orthophosphate in a sodium-dependent fashion. Consistent with a role in phosphate physiology, MSF13 is expressed highest in the Drosophila crop, midgut, Malpighian tubule, and hindgut. Altogether, our findings provide the first evidence that Pho84 orthologs mediate cellular effects of phosphate in metazoan cells. Finally, while phosphate is essential for Drosophila larval development, loss of MFS13 activity is compatible with viability indicating redundancy at the levels of the transporters.National Institutes of Health (U.S.) (NIDDK 5K08DK078361)Harvard Catalys

Internal Radiation Exposure Dose in Iwaki City, Fukushima Prefecture after the Accident at Fukushima Dai-ichi Nuclear Power Plant

As a result of the accident at the Fukushima Daiichi Nuclear Power Plant (FNPP) on 11 March 2011, a huge amount of radionuclides, including radiocesium, was released and spread over a wide area of eastern Japan. Although three years have passed since the accident, residents around the FNPP are anxious about internal radiation exposure due to radiocesium. In this study, we screened internal radiation exposure doses in Iwaki city of Fukushima prefecture, using a whole-body counter. The first screening was conducted from October 2012 to February 2013, and the second screening was conducted from May to November 2013. Study participants were employees of ALPINE and their families who underwent examination. A total of 2,839 participants (1,366 men and 1,473 women, 1-86 years old) underwent the first screening, and 2,092 (1,022 men and 1,070 women, 1-86 years old) underwent the second screening. The results showed that 99% of subjects registered below 300 Bq per body in the first screening, and all subjects registered below 300 Bq per body in the second screening. The committed effective dose ranged from 0.01-0.06 mSv in the first screening and 0.01-0.02 mSv in the second screening. Long-term follow-up studies are needed to avoid unnecessary chronic internal exposure and to reduce anxiety among the residents by communicating radiation health risks