Damage mechanisms of pathogenic bacteria in drinking water during chlorine and solar disinfection

This study aimed at elucidating the inactivation mechanisms of pathogenic bacteria in drinking water during chlorine and solar disinfection using a simple plating method. The well-known bacterial model Escherichia coli was used as pathogenic bacteria for the experiments. The damage mechanisms of E. coli were evaluated by simple plating method on selective, less selective and non-selective media. Results showed that, injured E. coli were detected at different levels during chlorine and solar disinfection. The use of selective media during water quality control showed effectively the destruction of E. coli during solar disinfection while the removal of E. coli during chlorine disinfection was not ensured. The damage of cell components and/or metabolic functions showed that there is a primary and mainly damage of E. coli during chorine and solar disinfection. Chlorination firstly and mainly damaged membrane cell followed by that of enzymatic functions and nucleic acid; while solar disinfection damaged mainly nucleic acid. The use of simple plating method in water quality control is limited by the choice of plating media depending on the disinfectant used. The understanding of the damage mechanisms of pathogenic bacteria cells during disinfection helps improve drinking water quality control and develops more effective disinfection strategies.© 2016 International Formulae Group. All rights reserved.Keywords: Drinking water, pathogenic bacteria, E. coli, damage mechanisms, chlorine disinfection, solar disinfectio

Tetrahydrouridine Inhibits Cell Proliferation through Cell Cycle Regulation Regardless of Cytidine Deaminase Expression Levels

Tetrahydrouridine (THU) is a well characterized and potent inhibitor of cytidine deaminase (CDA). Highly expressed CDA catalyzes and inactivates cytidine analogues, ultimately contributing to increased gemcitabine resistance. Therefore, a combination therapy of THU and gemcitabine is considered to be a potential and promising treatment for tumors with highly expressed CDA. In this study, we found that THU has an alternative mechanism for inhibiting cell growth which is independent of CDA expression. Three different carcinoma cell lines (MIAPaCa-2, H441, and H1299) exhibited decreased cell proliferation after sole administration of THU, while being unaffected by knocking down CDA. To investigate the mechanism of THU-induced cell growth inhibition, cell cycle analysis using flow cytometry was performed. This analysis revealed that THU caused an increased rate of G1-phase occurrence while S-phase occurrence was diminished. Similarly, Ki-67 staining further supported that THU reduces cell proliferation. We also found that THU regulates cell cycle progression at the G1/S checkpoint by suppressing E2F1. As a result, a combination regimen of THU and gemcitabine might be a more effective therapy than previously believed for pancreatic carcinoma since THU works as a CDA inhibitor, as well as an inhibitor of cell growth in some types of pancreatic carcinoma cells

DPEP1 Inhibits Tumor Cell Invasiveness, Enhances Chemosensitivity and Predicts Clinical Outcome in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers worldwide. To identify biologically relevant genes with prognostic and therapeutic significance in PDAC, we first performed the microarray gene-expression profiling in 45 matching pairs of tumor and adjacent non-tumor tissues from resected PDAC cases. We identified 36 genes that were associated with patient outcome and also differentially expressed in tumors as compared with adjacent non-tumor tissues in microarray analysis. Further evaluation in an independent validation cohort (N = 27) confirmed that DPEP1 (dipeptidase 1) expression was decreased (T: N ratio ∼0.1, P<0.01) in tumors as compared with non-tumor tissues. DPEP1 gene expression was negatively correlated with histological grade (Spearman correlation coefficient = −0.35, P = 0.004). Lower expression of DPEP1 in tumors was associated with poor survival (Kaplan Meier log rank) in both test cohort (P = 0.035) and validation cohort (P = 0.016). DPEP1 expression was independently associated with cancer-specific mortality when adjusted for tumor stage and resection margin status in both univariate (hazard ratio = 0.43, 95%CI = 0.24–0.76, P = 0.004) and multivariate analyses (hazard ratio = 0.51, 95%CI = 0.27–0.94, P = 0.032). We further demonstrated that overexpression of DPEP1 suppressed tumor cells invasiveness and increased sensitivity to chemotherapeutic agent Gemcitabine. Our data also showed that growth factor EGF treatment decreased DPEP1 expression and MEK1/2 inhibitor AZD6244 increased DPEP1 expression in vitro, indicating a potential mechanism for DPEP1 gene regulation. Therefore, we provide evidence that DPEP1 plays a role in pancreatic cancer aggressiveness and predicts outcome in patients with resected PDAC. In view of these findings, we propose that DPEP1 may be a candidate target in PDAC for designing improved treatments

Haplotype analysis of the human collectin placenta 1 (hCL-P1) gene

This is the author-created version of Springer, Ohmori, H; Makita, Y; Funamizu, M; Chiba, S; Ohtani, K; Suzuki, Y; Wakamiya, N; Hata, A, JOURNAL OF HUMAN GENETICS, 48(2), 2003, 82-85.鐃緒申The original publication is available at www.springerlink.com. authorCollectins are a family of C-type lectins that have collagen-like sequences and carbohydrate recognition domains (CRD). They are involved in host defense through their ability to bind to carbohydrate antigens of microorganisms. The scavenger receptors type A and macrophage receptor with collagenous structure are classical type scavenger receptors that have internal collagen-like domains. We previously described a new scavenger receptor that is membrane-type collectin from placenta (collectin placenta 1(CL-P1)). CL-P1 is a type II membrane protein, has a coiled coil region, a collagen-like domain, and a CRD. We found that CL-P1 can bind and phagocytes both bacteria and yeast. Furthermore, it reacts with oxidized low-density lipoprotein (OxLDL) but not with acetylated LDL (AcLDL). These results indicate that CL-P1 might play important roles in host defenses and/or atherosclerosis formation (Ohtani et al 2001). One rational strategy to study the role of CL-P1 in these pathological conditions would be a haplotype association study using human samples. As a first step for this strategy, we analyzed haplotype structure of the CL-P1 gene. Sequencing the CL-P1 gene region of ten Japanese volunteers identified five single-nucleotide polymorphisms (SNPs) with the minor allele frequency to be at least 29%. In order to obtain SNPs in the 5’-upstream region of the gene, total 20 SNPs described in publicly available database were screened, and we found one SNP out of 20 was useful for the present study. Thus, total six SNPs, one in 5’-upstream region, two in intron 2, one in exon 5, and two in exon 6, were employed to analyze the haplotype structure of the gene with DNAs derived from 54 individuals (108 alleles). The analysis revealed that only two of six SNPs showed significant linkage disequilibrium (r2>0.5) between each other. This haplotype information would be useful in disease-association studies where a contribution of CL-P1 gene has been suspected, especially in innate immunity defect or atherosclerosis. Two SNPs in exon 6, both lead to amino acid substitutions, could be attractive candidates to have some influence for disease susceptibility

Linkage and association analyses of the osteoprotegerin gene locus with human osteoporosis

This is the author-created version of Springer, Ohmori, H. ; Makita, Y. ; Funamizu, M. ; Hirooka, K. ; Hosoi, T. ; Orimo, H. ; Suzuki, T. ; Ikari, K. ; Nakajima, T. ; Inoue, I. ; Hata, A., JOURNAL OF HUMAN GENETICS, 47(8), 2002, 400-406. The original publication is available at www.springerlink.com. authorOsteoprotegerin (OPG), a secreted glycoprotein and a member of the TNF receptor superfamily, is considered to play an important role in the regulation of bone resorption through modifying osteoclast differentiation. Overexpression of OPG in mice has been reported to result in osteopetrosis, whereas targeted disruption of OPG in mice has been associated with osteoporosis. Accordingly, OPG could be a strong candidate gene for susceptibility of human osteoporosis. Here, we analyzed whether OPG is involved in the etiology of osteoporosis using both linkage and association analyses. We recruited 164 sib pairs in Gunma prefecture, which is located in the central part of Honshu (mainland Japan), for a linkage study, and 394 postmenopausal women in Akita prefecture, which is in the northern part of Honshu, for an association study. We identified two microsatellite polymorphisms for a linkage study, and six single nucleotide polymorphisms (SNPs) for an association study in the OPG region. Although, no evidence of significant linkage between OPG and osteoporosis was found, a possible association of one SNP, which locates in the promoter region of the gene, was identified. Haplotype analysis with six SNPs revealed that four major haplotypes account for 71% of the alleles in the Japanese population

Growth Kinetics Of Γ-Al12Mg17 And Β-Al3Mg2 Intermetallic Phases In Mg Vs. Al Diffusion Couples

Increasing use and development of lightweight Mg-alloys have led to the desire for more fundamental research in and understanding of Mg-based systems. As a strengthening component, Al is one of the most important and common alloying elements for Mg-alloys. In this study, solid-to-solid diffusion couple techniques were employed to examine the interdiffusion between pure Mg and Al. Diffusion anneals were carried out at 300°, 350°, and 400°C for 720, 360, and 240 hours, respectively. Optical and scanning electron microscopies (SEM) were employed to observe the formation of the intermetallics γ-Al12Mg17 and β-Al3Mg2, but not ε-phase. Concentration profiles were determined using X-ray energy dispersive spectroscopy (XEDS). The growth constants and activation energies were determined for each intermetallic phase