Drosophila Toll-9 is induced by aging and neurodegeneration to modulate stress signaling and its deficiency exacerbates tau-mediated neurodegeneration.

Drosophila Toll-9 is most closely related to mammalian Toll-like receptors; however, physiological functions of Toll-9 remain elusive. We examined the roles of Toll-9 in fly brains in aging and neurodegeneration. Toll-9 mRNA levels were increased in aged fly heads accompanied by activation of nuclear factor-kappa B (NF-kB) and stress-activated protein kinase (SAPK) signaling, and many of these changes were modulated by Toll-9 in glial cells. The loss of Toll-9 did not affect lifespan or brain integrity, whereas it exacerbated hydrogen peroxide-induced lethality. Toll-9 expression was also induced by nerve injury but did not affect acute stress response or glial engulfment activity, suggesting Toll-9 may modulate subsequent neurodegeneration. In a fly tauopathy model, Toll-9 deficiency enhanced neurodegeneration and disease-related tau phosphorylation with reduced SAPK activity, and blocking SAPK enhanced tau phosphorylation and neurodegeneration. In sum, Toll-9 is induced upon aging and nerve injury and affects neurodegeneration by modulating stress kinase signaling.

Recent Advances in Prion Inactivation by Plasma Sterilizer.

Prions, which cause transmissible spongiform encephalopathies (TSEs), are a notorious group of infectious agents with possibly the highest resistance to complete inactivation. Although various gas plasma instruments have been developed, studies on prion inactivation using gas plasma instruments are limited. Among them, the hydrogen peroxide gas plasma instrument, STERRAD® (Advanced Sterilization Products; ASP, Johnson & Johnson, Irvine, CA, USA), is recommended for prion inactivation of heat-sensitive medical devices. However, STERRAD® is not a plasma sterilizer but a hydrogen peroxide gas sterilizer. In STERRAD®, plasma generated by radio frequency (RF) discharge removes excess hydrogen peroxide gas and does not contribute to sterilization. This is also supported by evidence that the instrument was not affected by the presence or absence of RF gas plasma. However, recent studies have shown that other gas plasma instruments derived from air, nitrogen, oxygen, Ar, and a mixture of gases using corona, dielectric barrier, microwave, and pulse discharges can inactivate scrapie prions. As inactivation studies on prions other than scrapie are limited, further accumulation of evidence on the effectiveness of gas plasma using human-derived prion samples is warranted for practical purposes.

Effect of Non-Concentrated and Concentrated Vaporized Hydrogen Peroxide on Scrapie Prions.

To date, there have been no studies on the sterilization of prions by non-concentrated and concentrated vaporized hydrogen peroxide (VHP) applied by the same instrument. Here, the effect of the two types of VHP applied using an ES-700 sterilizer on prions was investigated. Brain homogenate from scrapie (Chandler) prion-infected mice was spotted on a cover glass and subjected to ES-700 treatment in soft (non-concentrated VHP from 59% hydrogen peroxide) or standard (concentrated VHP from 80% hydrogen peroxide) mode. Proteinase K-resistant prion protein (PrPres), an indicator of the abnormal isoform of prion protein (PrPSc), was reduced by ES-700 treatment under several conditions: SFT1/4 (soft mode, quarter cycle), SFT1/2 (soft mode, half cycle), SFT1 (soft mode, full cycle), and STD1/2 (standard mode, half cycle). PrPres was detected after the first and second rounds of protein misfolding cyclic amplification (PMCA) of untreated samples, but was undetectable in SFT1/4, SFT1/2, SFT1, and STD1/2 treated samples. In a mouse bioassay, SFT1/2 and STD1/2 treatment of prions significantly prolonged survival time, suggesting that prion infectivity is reduced after ES-700 treatment. In summary, both non-concentrated and concentrated VHP inactivate prions and may be useful for the low-temperature sterilization of prion-contaminated medical devices.

Inactivation of Non-Enveloped Viruses and Bacteria by an Electrically Charged Disinfectant Containing Meso-Structure Nanoparticles via Modification of the Genome.

INTRODUCTION: A previous study demonstrated the virucidal effect of an electrically charged disinfectant (CAC-717), which contains meso-structure nanoparticles, on enveloped viruses (influenza viruses). However, the effect of CAC-717 on other microorganisms and the mechanisms by which CAC-717 inactivates the microorganisms remain unclear. In this study, CAC-717 was further evaluated in terms of its biocidal and virucidal activity as well as its effect on bacterial and viral nucleic acids. METHODS: The inactivation effects of CAC-717 against various microorganisms [non-enveloped virus, feline calicivirus (FCV); bacteria, Salmonella enterica and Escherichia coli] were investigated by comparing the viral titer of the medium tissue culture infectious dose (TCID50) and the D value (estimated treatment time required to reduce the number of microorganisms by 90%). Furthermore, the effects of CAC-717 on viral and bacterial genomic RNA/DNA were examined using a polymerase chain reaction (PCR). RESULTS: Treatment of an equal volume of CAC-717 with cell lysate infected with a non-enveloped virus, feline calicivirus (FCV), reduced the TCID50. Viral titer dropped below the detection limit after 2 min of treatment. The D value of FCV was 0.256 min (average of multiple endpoint D values) and endpoint D value was 0.341 min. The D value for E. coli and S. enterica was 0.290 min and 0.080 min (average of multiple endpoint D values), respectively and the endpoint D value was 0.545 min and 0.054 min, respectively. In addition, PCR showed the inhibition of nucleic acid amplification of the RNA and DNA genome of FCV and bacteria, respectively. CONCLUSION: Our findings suggest that CAC-717 inactivates viruses and bacteria by modifying the viral and bacterial nucleic acids.

Efficient recovery and enrichment of infectious rotavirus using separation with antibody-integrated graphite-encapsulated magnetic nanobeads produced by argon/ammonia gas plasma technology.

BACKGROUND: Rotavirus is the representative cause of severe acute gastroenteritis in young children. A characteristic feature of rotavirus is low infectious dose and robustness of the virion, suggesting sanitation and hygiene will have little impact. Thus, development of a vaccine should be given priority. Efficient capture of infectious viruses is an important step in generating a vaccine. Previously, antibody-integrated magnetic nanobeads (MNBs) have been developed for virus capture. This study examines the applicability of this method for infectious rotavirus recovery and enrichment. MATERIALS AND METHODS: Graphite-encapsulated MNBs were treated with radio frequency (RF) excited Ar/NH3 gas mixture plasma to introduce amino groups onto their surfaces. Rotavirus viral protein 7 (VP7) antibody was attached to the surface of MNBs via these amino groups using a coupling agent, N-succinimidyl 3-(2-pyridyldithio)propionate (SPDP). The antibody-integrated MNBs were incubated with rotavirus-infected cell lysate and then separated from the supernatant by applying a magnetic field. After thorough washing, rotavirus was recovered and enrichment analysis done by polymerase chain reaction (PCR), immunochromatography, and an infection analysis using MA104 cells. RESULTS AND DISCUSSION: Immunochromatography and PCR indicate that anti-rotavirus antibody-integrated MNPs efficiently capture rotavirus with the capsid protein and viral RNA. The estimated recovery rate was 80.2% by PCR and 90.0% by infection analysis, while the concentrating factor was 7.9-fold by PCR and 6.7-fold by infection analysis. In addition, the absence of non-specific binding to the antibody-integrated MNPs was confirmed using anti-dengue virus antibody-integrated MNBs as a negative control. CONCLUSION: These results suggest that this capture procedure is a useful tool for recovery and enrichment of infectious rotavirus. Moreover, when combined with a suitable virus assay this capture procedure can increase the sensitivity of rotavirus detection. Therefore, this capture method is a valuable tool for generating vaccines as well as for developing sensitive detection systems for viruses.

Key role of singlet oxygen and peroxynitrite in viral RNA damage during virucidal effect of plasma torch on feline calicivirus.

A dielectric barrier discharge (DBD) plasma torch has been used to evaluate the mechanism underlying inactivation of feline calicivirus (FCV) by plasma treatment. Plasma treatment of cell lysate infected with FCV F9 strain reduced the viral titer of the median tissue culture infectious dose (TCID50). The D value (treatment time required to lower the viral titer to 1/10) was 0.450 min, while the viral titer dropped below the detection limit within 2 min. FCV was not significantly inactivated by heat or UV applied at levels corresponding to those generated from the DBD plasma torch after 2 min (38.4 °C and 46.79 mJ/cm2 UV, respectively). However, TCID50 was reduced by 2.47 log after exposure to 4.62 mM ONOO-, corresponding to the concentration generated after 2 min of plasma treatment. Radical scavengers, including superoxide dismutase, dimethyl sulfoxide, and catalase, did not significantly affect viral titers; however, sodium azide, uric acid, and ascorbic acid, which are scavengers of 1O2 radicals, ONOO-, and peroxynitrous acid (ONOOH; produced from ONOO- under acidic conditions), respectively, significantly increased TCID50 and intact viral RNA. These findings suggest that ONOO- and 1O2 play an important role in FCV inactivation by attacking viral RNA during DBD plasma torch treatment.

Castalagin and vescalagin purified from leaves of Syzygium samarangense (Blume) Merrill & L.M. Perry: Dual inhibitory activity against PARP1 and DNA topoisomerase II.

Inhibition of poly(ADP-ribose) polymerase 1 (PARP1) is one of the most promising strategies for cancer chemotherapy, and a number of inhibitors possessing nicotinamide-like structures are being developed. To discover new types of PARP1 inhibitors, we screened a large number of substances of plant origin and isolated two inhibitory substances from the leaves of Syzygium samarangense (Blume) Merrill & L.M. Perry. The inhibitory substances were identified as vescalagin and its epimer castalagin by analyses using nuclear magnetic resonance and mass spectrometry. The IC50 of purified vescalagin and castalagin for PARP1 inhibition were 2.67 and 0.86 µM, respectively. Unlike most of synthetic PARP1 inhibitors, castalagin showed a mixed type inhibition, of which Ki was 1.64 µM. When SH-SY5Y cells were treated with these ellagitannins at concentrations of less than 5 µM, cellular poly(ADP-ribosyl)ation was obviously attenuated. Castalagin and vescalagin also possessed inhibitory activity against DNA topoisomerase II, implying that they function as dual inhibitors in cells.

Treatment of Helicobacter pylori with dielectric barrier discharge plasma causes UV induced damage to genomic DNA leading to cell death.

Gastrointestinal endoscopy is an important tool for the indentification and treatment of disorders of the gastrointestinal tract. However, nosocomial infections of Helicobacter pylori have been linked to the use of contaminated endoscopes. Disinfectants such as glutaraldehyde, ortho-phthalaldehyde and peracetic acid are generally used in the reprocesssing of endoscopes, but these chemicals are hazardous to human health. Thus, safer reprocessing and disinfecion methods are needed. In this study, we applied a dielectric barrier discharge (DBD) plasma torch for inactivation of H. pylori to investigate a potential new methodology to disinfect endoscopes. Suspensions of H. pylori in 10% glycerol were subjected to the DBD plasma torch, which reduced the viable cell count to undetectable levels after 2 min of treatment. Furthermore, urease activity of H. pylori was eliminated after 2 min-plasma treatment, while plasma-treatment reduced the intact DNA of H. pylori in a time-dependent manner. Next, we examined several potential bactericidal factors produced by the DBD plasma torch. Two min-plasma treatment resulted in a small temperature rise (4 °C), ultraviolet radiation (UV) generation, and the production of hydrogen peroxide. H. pylori samples were then exposed to equivalent levels of each of these factors in turn. Our results showed that treatment with heat and hydrogen peroxide at the levels produced after 2-min of plasma treatment did not efficiently inactivate H. pylori, whereas exposure to UV had a significant bactericidal effect. Taken together, UV generated by the plasma torch may be crucial for efficient inactivation of H. pylori by damaging the bacterial DNA.