Mechanisms of Sporicidal Activity Induced by Ionized Hydrogen Peroxide in the Spores of Bacillus atrophaeus

The main objective of this study was to make out the decontamination effects of bacillus atrophaeus in different locations by Vaporous Hydrogen Peroxide decontamination equipment which was designed independently. Bacillus atrophaeus were in different locations of the room, the room volume is 67m3. Then the Vaporous Hydrogen Peroxide (VHP) decontamination equipment was opened to sterilize the room. After the sterilization, based on the Technical Standard For disinfection, the biological indicators including bacillus atrophaeus were incubated at37 °C for 48 hr,resultant colonies were enumerated. The BI results showed that along with the increase of distance between VHP decontamination equipment and the BI, decontamination time gradually extended. When the distance were 2m, 4m and 6m, the decontamination time were 15min, 30min and 30min. When the BI was put in the room corner, the decontamination time was 60min. From this paper,it can be determined that the VHP technology is a valid approach to the sterilization of interior space.

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Effect of Sporulation Conditions Following Submerged Cultivation on the Resistance of Bacillus atrophaeus Spores against Inactivation by H2O2

Molecules ◽

10.3390/molecules25132985 ◽

2020 ◽

Vol 25 (13) ◽

pp. 2985

Author(s):

Philipp Stier ◽

Ulrich Kulozik

Keyword(s):

Hydrogen Peroxide ◽

Biological Indicator ◽

Submerged Cultivation ◽

Bacillus Atrophaeus ◽

Random Variability ◽

Aseptic Packaging ◽

Safe Food ◽

D Values ◽

Shelf Stable ◽

D Value

The resistance formation of spores in general and of Bacillus atrophaeus in particular has long been the focus of science in the bio-defense, pharmaceutical and food industries. In the food industry, it is used as a biological indicator (BI) for the evaluation of the inactivation effects of hydrogen peroxide in processing and end packaging lines’ sterilization. Defined BI resistances are critical to avoid false positive and negative tests, which are salient problems due to the variable resistance of currently available commercial BIs. Although spores for use as BIs have been produced for years, little is known about the influence of sporulation conditions on the resistance as a potential source of random variability. This study therefore examines the dependence of spore resistance on the temperature, pH and partial oxygen saturation during submerged production in a bioreactor. For this purpose, spores were produced under different sporulation conditions and their resistance, defined by the D-value, was determined using a count reduction test in tempered 35% liquid hydrogen peroxide. The statistical analysis of the test results shows a quadratic dependence of the resistance on the pH, with the highest D-values at neutral pH. The sporulation temperature has a linear influence on the resistance. The higher the temperature, the higher the D-value. However, these factors interact with each other, which means that the temperature only influences the resistance when the pH is within a certain range. The oxygen partial pressure during sporulation has no significant influence. Based on the data obtained, a model could be developed enabling the resistance of BIs to be calculated, predicted and standardized depending on the sporulation conditions. BI manufacturers could thus produce BIs with defined resistances for the validation of sterilization effects in aseptic packaging/filling lines for the reliable manufacture of shelf-stable and safe food products.

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Peroxidase Localization in Hartmanella Trophozoites

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100065778 ◽

1971 ◽

Vol 29 ◽

pp. 346-347 ◽

Cited By ~ 1

Author(s):

George E. Childs ◽

Joseph H. Miller

Keyword(s):

Hydrogen Peroxide ◽

Ultrastructural Localization ◽

Pathogenic Strain ◽

Oxidative Enzymes ◽

Differential Centrifugation ◽

Electron Microscopic ◽

Microscopic Studies ◽

The Subject ◽

Axenic Cultures

Biochemical and differential centrifugation studies have demonstrated that the oxidative enzymes of Acanthamoeba sp. are localized in mitochondria and peroxisomes (microbodies). Although hartmanellid amoebae have been the subject of several electron microscopic studies, peroxisomes have not been described from these organisms or other protozoa. Cytochemical tests employing diaminobenzidine-tetra HCl (DAB) and hydrogen peroxide were used for the ultrastructural localization of peroxidases of trophozoites of Hartmanella sp. (A-l, Culbertson), a pathogenic strain grown in axenic cultures of trypticase soy broth.

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Fluorescent proteins for in vivo imaging, where's the biliverdin?

Biochemical Society Transactions ◽

10.1042/bst20200444 ◽

2020 ◽

Vol 48 (6) ◽

pp. 2657-2667

Author(s):

Felipe Montecinos-Franjola ◽

John Y. Lin ◽

Erik A. Rodriguez

Keyword(s):

Hydrogen Peroxide ◽

In Vivo Imaging ◽

Near Infrared ◽

Fluorescent Protein ◽

Fluorescent Proteins ◽

Fluorescent Imaging ◽

Infrared Light ◽

Red Fluorescent Protein ◽

Color Palette

Noninvasive fluorescent imaging requires far-red and near-infrared fluorescent proteins for deeper imaging. Near-infrared light penetrates biological tissue with blood vessels due to low absorbance, scattering, and reflection of light and has a greater signal-to-noise due to less autofluorescence. Far-red and near-infrared fluorescent proteins absorb light >600 nm to expand the color palette for imaging multiple biosensors and noninvasive in vivo imaging. The ideal fluorescent proteins are bright, photobleach minimally, express well in the desired cells, do not oligomerize, and generate or incorporate exogenous fluorophores efficiently. Coral-derived red fluorescent proteins require oxygen for fluorophore formation and release two hydrogen peroxide molecules. New fluorescent proteins based on phytochrome and phycobiliproteins use biliverdin IXα as fluorophores, do not require oxygen for maturation to image anaerobic organisms and tumor core, and do not generate hydrogen peroxide. The small Ultra-Red Fluorescent Protein (smURFP) was evolved from a cyanobacterial phycobiliprotein to covalently attach biliverdin as an exogenous fluorophore. The small Ultra-Red Fluorescent Protein is biophysically as bright as the enhanced green fluorescent protein, is exceptionally photostable, used for biosensor development, and visible in living mice. Novel applications of smURFP include in vitro protein diagnostics with attomolar (10−18 M) sensitivity, encapsulation in viral particles, and fluorescent protein nanoparticles. However, the availability of biliverdin limits the fluorescence of biliverdin-attaching fluorescent proteins; hence, extra biliverdin is needed to enhance brightness. New methods for improved biliverdin bioavailability are necessary to develop improved bright far-red and near-infrared fluorescent proteins for noninvasive imaging in vivo.

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Protective effect of chitooligosaccharides on hydrogen peroxide-induced PC-12 cells death by inhibition of oxidative damage

Cell Biology International ◽

10.1042/cbi034s027d ◽

2010 ◽

Vol 34 (8) ◽

pp. S27-S27

Author(s):

Xueling Dai ◽

Ping Chang ◽

Ke Xu ◽

Changjun Lin ◽

Hanchang Huang ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Oxidative Damage ◽

Protective Effect ◽

Pc 12 Cells ◽

Cells Death

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Signal-regulated oxidation of proteins via MICAL

Biochemical Society Transactions ◽

10.1042/bst20190866 ◽

2020 ◽

Vol 48 (2) ◽

pp. 613-620

Author(s):

Clara Ortegón Salas ◽

Katharina Schneider ◽

Christopher Horst Lillig ◽

Manuela Gellert

Keyword(s):

Signal Transduction ◽

Hydrogen Peroxide ◽

Cell Death ◽

Redox Regulation ◽

Signal Transduction Pathways ◽

Cellular Functions ◽

Intracellular Signals ◽

Amino Acid Side Chains ◽

Specific Receptors ◽

Sulfur Containing

Processing of and responding to various signals is an essential cellular function that influences survival, homeostasis, development, and cell death. Extra- or intracellular signals are perceived via specific receptors and transduced in a particular signalling pathway that results in a precise response. Reversible post-translational redox modifications of cysteinyl and methionyl residues have been characterised in countless signal transduction pathways. Due to the low reactivity of most sulfur-containing amino acid side chains with hydrogen peroxide, for instance, and also to ensure specificity, redox signalling requires catalysis, just like phosphorylation signalling requires kinases and phosphatases. While reducing enzymes of both cysteinyl- and methionyl-derivates have been characterised in great detail before, the discovery and characterisation of MICAL proteins evinced the first examples of specific oxidases in signal transduction. This article provides an overview of the functions of MICAL proteins in the redox regulation of cellular functions.

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