Possible association of beta-arrestin 2 gene with methamphetamine use disorder, but not schizophrenia

Recent investigations suggest that the AKT/glycogen synthase kinase 3 (GSK3) signaling cascade may be associated with the pathophysiology of schizophrenia and methamphetamine (METH) use disorder. One important molecule related to this cascade is beta-arrestin 2 (ARRB2). We therefore conducted a genetic case-control association analysis of the gene for ARRB2 with schizophrenia and METH use disorder in a Japanese population (547 people with schizophrenia, 177 with METH use disorder and 546 controls). A possible association of 'tag single nucleotide polymorphisms (SNPs)' was found in METH use disorder (rs1045280: P(genotype) = 0.0118, P(allele) = 0.00351; rs2036657: P(allele) = 0.0431; rs4790694: P(genotype) = 0.0167, P(allele) = 0.0202), but no association was found with schizophrenia. We also evaluated the gene-gene interactions among ARRB2, AKT1, and GSK3B, which we previously reported for each of these diseases. However, no interaction was seen in our samples. This is the first association analysis of ARRB2, and our results indicate that ARRB2 may play a role in the pathophysiology of METH use disorder.     

Effect of intragastric ammonia on gastrin-, somatostatin-and somatostatin receptor subtype 2 positive-cells in rat antral mucosa.

Somatostatin suppresses gastrin and somatostatin secretion via somatostatin receptors (SSTRs). Ammonia produced by Helicobacter pylori has been reported to modify gastric gastrin and somatostatin levels. We investigated the distribution of SSTR-subtype 2 (SSTR-2) in relation to gastrin- and somatostatin-containing cells and the effect of ammonia solution (0.01%-0.1%) administered orally for 2 to 4 weeks on these cells in rat antral mucosa by immunohistochemistry. The majority of SSTR-2 peptide [31-41]-positive cells were located in the basal third of the glands. Double staining experiments revealed that SSTR-2 peptide [31-41]-positive cells are co-localized in 85.0 +/- 2.2% of the gastrin-containing cells and in 34.4 +/- 4.8% of the somatostatin-containing cells. Ammonia solution significantly decreased the number of somatostatin-containing cells and increased the proportion of SSTR-2 peptide [31-41]-labeling in the somatostatin-containing cells in a duration-dependent manner. Maximum changes were observed in rats treated with ammonia solution at the lowest level of 0.01% accompanied by an increase in serum gastrin levels in the portal vein. Sodium hydroxide at the similar pH to 0.01% ammonia solution had no effect. These findings suggest that SSTR-2 are localized in antral endocrine cells and that ammonia solution mainly decreases somatostatin-containing cells without SSTR-2 expression, resulting in an increase in gastrin secretion into the portal vein.     

Characterization of Helicobacter pylori Bacteriophage KHP30

Helicobacter pylori inhabits the stomach mucosa and is a causative agent of stomach ulcer and cancer. In general, bacteriophages (phages) are strongly associated with bacterial evolution, including the development of pathogenicity. Several tailed phages have so far been reported in H. pylori. We have isolated an H. pylori phage, KHP30, and reported its genomic sequence. In this study, we examined the biological characteristics of phage KHP30. Phage KHP30 was found to be a spherical lipid-containing phage with a diameter of ca. 69 nm. Interestingly, it was stable from pH 2.5 to pH 10, suggesting that it is adapted to the highly acidic environment of the human stomach. Phage KHP30 multiplied on 63.6% of clinical H. pylori isolates. The latent period was ca. 140 min, shorter than the doubling time of H. pylori (ca. 180 min). The burst size was ca. 13, which was smaller than the burst sizes of other known tailed or spherical phages. Phage KHP30 seemed to be maintained as an episome in H. pylori strain NY43 cells, despite a predicted integrase gene in the KHP30 genomic sequence. Seven possible virion proteins of phage KHP30 were analyzed using N-terminal protein sequencing and mass spectrometry, and their genes were found to be located on its genomic DNA. The genomic organization of phage KHP30 differed from the genomic organizations in the known spherical phage families Corticoviridae and Tectiviridae. This evidence suggests that phage KHP30 is a new type of spherical phage that cannot be classified in any existing virus category.     

Association analysis of SOD2 variants with methamphetamine psychosis in Japanese and Taiwanese populations

SOD2 (superoxide dismutase 2) plays a crucial role in protecting the cells against damage caused by free radicals, by catalyzing their detoxification. On the other hand, cell damage caused by free radical generation following methamphetamine administration has been postulated as one of the possible pathophysiological mechanisms for methamphetamine psychosis. Hence, we investigated the association of SOD2 polymorphisms with the development of methamphetamine psychosis, in two independent populations of Japan and Taiwan. We recruited 116 patients with methamphetamine psychosis and 189 controls in Japan, and 135 patients with methamphetamine psychosis and 204 controls in Taiwan. The methamphetamine group was divided into two clinical subtypes: a transient type of psychosis (i.e., good prognosis) and a prolonged type of psychosis (i.e., poor prognosis), according to the course of the manifestation of psychosis. With reference to the genotypic and allelic frequencies of Ala/Val functional polymorphism in exon 2, we found significant differences between individuals with prolonged methamphetamine psychosis and control samples from Japan and Taiwan in the genotypic (P value 0.014 and 0.016, respectively) and in the allelic (P value 0.004 and 0.047, respectively) frequencies. Our results suggest that Ala/Val polymorphism of the SOD2 gene could be associated with the risk of developing methamphetamine psychosis.     

Characterization of lytic enzyme open reading frame 9 (ORF9) derived from Enterococcus faecalis bacteriophage phiEF24C

In bacteriophage (phage) therapy against Gram-positive bacteria, such as Staphylococcus aureus, Listeria monocytogenes, and Enterococcus faecalis, members of a genus of SPO1-like viruses are typically employed because of their extreme virulence and broad host spectrum. Phage φEF24C, which is a SPO1-like virus infecting E. faecalis, has previously been characterized as a therapeutic phage candidate. In addition to the phage itself, phage endolysin is also recognized as an effective antimicrobial agent. In this study, a putative endolysin gene (orf9) of E. faecalis phage φEF24C was analyzed in silico, and its activity was characterized using the recombinant form. First, bioinformatics analysis predicted that the open reading frame 9 (ORF9) protein is N-acetylmuramoyl-l-alanine amidase. Second, bacteriolytic and bactericidal activities of ORF9 against E. faecalis were confirmed by zymography, decrease of peptidoglycan turbidity, decrease of the viable count, and morphological analysis of ORF9-treated cells. Third, ORF9 did not appear to require Zn(2+) ions for its activity, contrary to the bioinformatics prediction of a Zn(2+) ion requirement. Fourth, the lytic spectrum was from 97.1% (34 out of 35 strains, including vancomycin-resistant strains) of E. faecalis strains to 60% (6 out of 10 strains) of Enterococcus faecium strains. Fifth, N-acetylmuramoyl-l-alanine amidase activity of ORF9 was confirmed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and the subsequent MALDI-postsource decay (PSD) analyses. Finally, functional analysis using N- or C-terminally deleted ORF9 mutants suggested that a complete ORF9 molecule is essential for its activity. These results suggested that ORF9 is an endolysin of phage φEF24C and can be a therapeutic alternative to antibiotics.     

siRNAs generated by recombinant human Dicer induce specific and significant but target site-independent gene silencing in human cells

RNA interference has emerged as a powerful tool for the silencing of gene expression in animals and plants. It was reported recently that 21 nt synthetic small interfering RNAs (siRNAs) specifically suppressed the expression of endogenous genes in several lines of mammalian cells. However, the efficacy of siRNAs is dependent on the presence of a specific target site within the target mRNA and it remains very difficult to predict the best or most effective target site. In this study, we demonstrate that siRNAs that have been generated in vitro by recombinant human Dicer (re-hDicer) significantly suppress not only the exogenous expression of a puromycin-resistance gene but also the endogenous expression of H-ras, c-jun and c-fos. In our system, selection of a target site is not necessary in the design of siRNAs. However, it is important to avoid homologous sequences within a target mRNA in a given protein family. Our diced siRNA system should be a powerful tool for the inactivation of genes in mammalian cells.     

A study of boron adsorption onto activated sludge

Boron adsorption onto activated sludge was investigated using bench-scale reactors under simulated wastewater treatment conditions. Two experiments, continuous flow and batch, were performed. Boron concentrations were determined by means of inductively coupled plasma mass spectrometry. The results of the continuous-flow experiment indicated that a small amount of boron accumulated on the activated sludge and its concentration in the sludge depended on the nature of the biota in the sludge. Freundlich and Langmuir isotherm plots generated using the data from the batch experiment indicated that boron was adsorbed onto rather than absorbed into the sludge. The Freundlich constants, k and 1/n, were determined to be 26 mg/kg and 0.87. These values indicate that activated sludge has a limited capacity for boron adsorption and thus utilization of the excess sludge for farmland may not be toxic to plant at least boron concern.