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1.
A. Kneteman 《Antonie van Leeuwenhoek》1947,13(1):55-62
Summary In this paper a special culture medium for the detection of H2O2 formed by bacteria producing acid from glucose and by certain moulds is discussed and the preparation of the same is described. This medium can be used with success instead of the blood benzidine medium and was found to be decidedly more sensitive in so far that it allows to trace very small quantities of H2O2. The mineral manganese peroxide as used in this medium differs in many respects from the precipitate obtained by mixing solutions of manganous sulfate and permanganate as used bySöhngen.Experiments with moulds have given indications as regards the production of a soluble glucose oxidase. 相似文献
2.
Temporary parasitism by individual of the wood-decaying basidiomycete Lenzites betulina allows them to gain selective access to wood occupied by populations of pioneer basidiomycete colonisers in the genus Coriolus. Pseudotrametes gibbosa is similarly temporarily parasitic on species of Bjerkandera. This strategy facilitates possession by the parasites of a large mycelial domain, which in turn allows them to produce large sporophores with a high reproductive output. This behaviour strongly resembles that of strangler figs and temporary social parasitism in ants. 相似文献
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Rogers JV Sabourin CL Choi YW Richter WR Rudnicki DC Riggs KB Taylor ML Chang J 《Journal of applied microbiology》2005,99(4):739-748
AIMS: To evaluate the decontamination of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surface materials using hydrogen peroxide gas. METHODS AND RESULTS: Bacillus anthracis, B. subtilis, and G. stearothermophilus spores were dried on seven types of indoor surfaces and exposed to > or =1000 ppm hydrogen peroxide gas for 20 min. Hydrogen peroxide exposure significantly decreased viable B. anthracis, B. subtilis, and G. stearothermophilus spores on all test materials except G. stearothermophilus on industrial carpet. Significant differences were observed when comparing the reduction in viable spores of B. anthracis with both surrogates. The effectiveness of gaseous hydrogen peroxide on the growth of biological indicators and spore strips was evaluated in parallel as a qualitative assessment of decontamination. At 1 and 7 days postexposure, decontaminated biological indicators and spore strips exhibited no growth, while the nondecontaminated samples displayed growth. CONCLUSIONS: Significant differences in decontamination efficacy of hydrogen peroxide gas on porous and nonporous surfaces were observed when comparing the mean log reduction in B. anthracis spores with B. subtilis and G. stearothermophilus spores. SIGNIFICANCE AND IMPACT OF THE STUDY: These results provide comparative information for the decontamination of B. anthracis spores with surrogates on indoor surfaces using hydrogen peroxide gas. 相似文献
5.
《Fungal Ecology》2021
We examined whether sporocarp carbon and nitrogen isotope ratios (δ13C and δ15N values) reflected different functional strategies in 15 species of wood decay fungi. In Finnish Picea abies forests, we compared sporocarp δ13C and δ15N against log diameter, proximity to ground, and three wood decay types, specifically brown rot, nonselective white rot, and selective white rot (targeting hemicellulose and lignin preferentially). In regression analysis (adjusted r2 = 0.576), species accounted for 31% of variability in δ13C, with factors influencing wood δ13C accounting for the remainder. Brown rot fungi and three white rot fungi that selectively attacked hemicellulose (Heterobasidion parviporum, Phellopilus nigrolimitatus, and Trichaptum abietinum) were higher in δ13C than nonselective white rot fungi. This was attributed to greater assimilation of 13C-enriched pentoses from hemicellulose by these fungi. The pathogenic white rot fungus Heterobasidion parviporum had higher δ15N with proximity to ground and increasing log diameter. This suggested that 15N-enriched soil N contributed to decomposing logs and that Heterobasidion growing from a bigger resource base had increased access to soil N. These isotopic patterns accordingly reflected both functional diversity of wood decay fungi and site-specific factors. 相似文献
6.
Succinate diesters of medium-chain fatty alcohols (C6, C8, C10 C12) was prepared to be studied on their ability to induce nutritional encephalomalacia in starting chicks and on the mechanism of their hydrolysis, absorption, and transport in chicks, using dilauryl succinate as positive control which possesses strong ability to induce encephalomalacia. It was revealed that all the succinate diesters used in this experiment, i.e., dilauryl succinate, monodecyl-monolauryl succinate, monooctyl-monolauryl succinate, monohexyl-monolauryl succinate, didecyl succinate, dioctyl succinate, and dihexyl succinate had ability to induce encephalomalacia in starting chicks. It was observed that succinate diesters were hydrolysed into monoesters and free alcohols mainly in the region between jej unum and ileum, and absorbed to the portal vein in the form of monoester and free alcohol, not in intact form as diester, and transported to the liver. The possible proposal that monoesters will be most important compound for the induction of encephalomalacia is discussed. 相似文献
7.
We have reported previously that the apparent rate of peroxynitrite (ONOO-) decay, as followed from its absorbance at 302 nm, decreases in the presence of hydrogen peroxide, mannitol and ethanol (Alvarez et al., 1995, Chem. Res. Toxicol. 8:859-864; Alvarez et al., 1998, Free Radic. Biol. Med. 24:1331–1337). Recently, two papers confirmed the observation and proposed that this slowing effect was due to the formation of absorbing peroxynitrate (O2NOO-) as intermediate (Goldstein and Czapski, 1998, J. Am. Chem. Soc. 120:3458–3463; Hodges and Ingold, 1999, J. Am. Chem. Soc. 121:10695–10701). Peroxynitrate would be formed from the reaction of peroxynitrite-derived nitrogen dioxide with superoxide. Superoxide, in turn, would arise from the one-electron oxidation of hydrogen peroxide, or from the reaction of reductive radicals derived from mannitol and ethanol with dioxygen. In agreement with this concept, we show herein that under the conditions of our previous work, the slowing effect is prevented by superoxide dismutase and, in the case of mannitol and ethanol, by reducing the dioxygen concentration of the reaction solutions. Thus, superoxide formation is necessary for the decrease in the rate of absorbance decay. In addition, by simulations using known rate constants and absorption coefficients, we show that the slowing effect can be quantitatively accounted for by the formation of peroxynitrate. 相似文献
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A convenient and simple electrophoretic procedure was used to study the NAD(P)H-dependent generation of the hydrogen peroxide needed for the polymerization of coniferyl alcohol by peroxidases from the wood of Ailanthus glandulosa. The results showed that an NAD(P)H-dependent generation of hydrogen peroxide could be brought about by either: a FMN or riboflavin-dependent system; or a Mn2+ -dependent system. The most active system was the one incorporating Mn2+, followed closely by that incorporating riboflavin. In nature it appears that the method of hydrogen peroxide formation is determined by the amounts of cofactors present in the lignifying tissue. Because no quantitative data are available in the literature, further studies of the concentrations of these cofactors in the plant cell-wall are needed. 相似文献
10.
Aims: To determine the effects of cysteine, cystine, proline and thioproline as sporulation medium supplements on Bacillus subtilis spore resistance to hydrogen peroxide (H2O2), wet heat, and germicidal 254 nm and simulated environmental UV radiation. Methods and Results: Bacillus subtilis spores were prepared in a chemically defined liquid medium, with and without supplementation of cysteine, cystine, proline or thioproline. Spores produced with thioproline, cysteine or cystine were more resistant to environmentally relevant UV radiation at 280–400 and 320–400 nm, while proline supplementation had no effect. Spores prepared with cysteine, cystine or thioproline were also more resistant to H2O2 but not to wet heat or 254‐nm UV radiation. The increases in spore resistance attributed to the sporulation supplements were eliminated if spores were chemically decoated. Conclusions: Supplementation of sporulation medium with cysteine, cystine or thioproline increases spore resistance to solar UV radiation reaching the Earth’s surface and to H2O2. These effects were eliminated if the spores were decoated, indicating that alterations in coat proteins by different sporulation conditions can affect spore resistance to some agents. Significance and Impact of the Study: This study provides further evidence that the composition of the sporulation medium can have significant effects on B. subtilis spore resistance to UV radiation and H2O2. This knowledge provides further insight into factors influencing spore resistance and inactivation. 相似文献
11.
Hydrophobic protein (H protein) was isolated from membrane fractions of Bacillus subtilis and constituted into artificial membrane vesicles with lipid of B. substilis. Glutamate was accumulated into the vesicle when a Na+ gradient across the membrane was imposed. The maximum effect of Na+ on the transport was achieved at a concentration of about 40 mM, while the apparent Km for Na+ was approximately 8 mM. On the other hand, Km for glutamate in the presence of 50 mM Na+ was about 8 μM. Increasing the concentration of Na+ resulted in a decrease in Km for glutamate, maximum velocity was not affected. The transport was sensitive to monensin (Na+ ionophore).Glutamate was also accumulated when pH gradient (interior alkaline) across the membrane was imposed or a membrane potential was induced with K+-diffusion potential. The pH gradient-driven glutamate transport was sensitive to carbonylcyanide m-chlorophenylhydrazone and the apparent Km for glutamate was approximately 25 μM.These results indicate that two kinds of glutamate transport system were present in H protein: one is Na+ dependent and the other is H+ dependent. 相似文献
12.
Kakeshita H Takamatsu H Amikura R Nakamura K Watabe K Yamane K 《FEMS microbiology letters》2001,195(1):41-46
Bacillus subtilis FtsY is a homolog of the alpha-subunit of mammalian signal recognition particle (SRP) receptor, and is essential for protein translocation and vegetative cell growth. An FtsY conditional null mutant (strain ISR39) can express ftsY during the vegetative stage but not during spore formation. Spores of ISR39 have the same resistance to heat and chloroform as the wild-type, while their resistance to lysozyme is reduced. Electron microscopy showed that the outer coat of spores was incompletely assembled. The coat protein profile of the ftsY mutant spores was different from that of wild-type spores. The amounts of CotA, and CotE were reduced in spore coat proteins of ftsY mutant spores and the molecular mass of CotB was reduced. In addition, CotA, CotB, and CotE are present in normal form at T(8) of sporulation in ftsY mutant cells. These results suggest that FtsY has a pivotal role in assembling coat proteins onto the coat layer during spore morphogenesis. 相似文献
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Abstract Using promoter-probe plasmids, more than 200 promoter-containing fragments from Bacillus stearothermophilus and Bacillus subtilis were cloned in B. subtilis . Among these, 15 promoter fragments were highly temperature-dependent in activity compared to the promoter sequence (TTGAAA for the −35 region, TATAAT for the −10 region) of the amylase gene, amyT , from B. stearothermophilus . Some fragments exhibited higher promoter activities at elevated temperature (48°C), others showed higher activities at lower temperature (30°C). Active promoter fragments at higher and lower temperatures were obtained mainly from the thermophile ( B. stearothermophilus ) and the mesophile ( B. subtilis ), respectively. A promoter fragment active at high temperature was sequenced, and the feature of the putative promoter region was discussed. 相似文献
16.
Effect of broad-band ultraviolet and visible radiation on hydrogen peroxide formation by cultured rose cells 总被引:1,自引:0,他引:1
Terence M. Murphy 《Physiologia plantarum》1990,80(1):63-68
Broad-band radiation from a high-pressure Hg-vapor lamp, including ultraviolet wavelengths from 290 to 400 nm, blue, green and red wavelengths, did not induce the synthesis of H2 O2 in cultured rose cells. This was in contrast to the effects of shortwave (254 nm) ultraviolet radiation, even though, like shortwave ultraviolet radiation, the UV-B component of the broadband radiation induced a striking K+ efflux from the cells, and this efflux has been associated with H2 O2 synthesis in a previous report. The UV-A and visible wavelengths were shown to inhibit the synthesis of H2 O2 . This effect was associated with inhibition of peroxidase, an enzyme reported to be involved in the synthesis of H2 O2 in cell walls. UV-B radiation inhibited the alternate pathway for mitochondrial electron transport, but there was no evidence that this effect contributed to the inhibition of H2 O2 synthesis in cells treated with broad-band radiation. 相似文献
17.
Takac I Schröder K Zhang L Lardy B Anilkumar N Lambeth JD Shah AM Morel F Brandes RP 《The Journal of biological chemistry》2011,286(15):13304-13313
In contrast to the NADPH oxidases Nox1 and Nox2, which generate superoxide (O(2)(·-)), Nox4 produces hydrogen peroxide (H(2)O(2)). We constructed chimeric proteins and mutants to address the protein region that specifies which reactive oxygen species is produced. Reactive oxygen species were measured with luminol/horseradish peroxidase and Amplex Red for H(2)O(2) versus L-012 and cytochrome c for O(2)(·-). The third extracytosolic loop (E-loop) of Nox4 is 28 amino acids longer than that of Nox1 or Nox2. Deletion of E-loop amino acids only present in Nox4 or exchange of the two cysteines in these stretches switched Nox4 from H(2)O(2) to O(2)(·-) generation while preserving expression and intracellular localization. In the presence of an NO donor, the O(2)()-producing Nox4 mutants, but not wild-type Nox4, generated peroxynitrite, excluding artifacts of the detection system as the apparent origin of O(2)(·-). In Cos7 cells, in which Nox4 partially localizes to the plasma membrane, an antibody directed against the E-loop decreased H(2)O(2) but increased O(2)(·-) formation by Nox4 without affecting Nox1-dependent O(2)(·-) formation. The E-loop of Nox4 but not Nox1 and Nox2 contains a highly conserved histidine that could serve as a source for protons to accelerate spontaneous dismutation of superoxide to form H(2)O(2). Mutation of this but not of four other conserved histidines also switched Nox4 from H(2)O(2) to O(2)(·-) formation. Thus, H(2)O(2) formation is an intrinsic property of Nox4 that involves its E-loop. The structure of the E-loop may hinder O(2)(·-) egress and/or provide a source for protons, allowing dismutation to form H(2)O(2). 相似文献
18.
Manuel Valmaseda Gonzalo Almendros Angel T. Martínez 《Applied microbiology and biotechnology》1990,33(4):481-484
Summary The ability of 45 fungal strains to degrade wheat straw and beech wood was studied. Degradation patterns were defined in terms of chemical evolution of substrates and changes in lignin and polysaccharides. Trametes versicolor produced an important degradation of lignin and increased substrate digestibility, but it caused high weight losses and gave rise to similar decay patterns on both substrates. A preferential degradation of lignin was produced during straw transformation by Pleurotus eryngii. The increase of soluble lignin and decreases of lignin content and H/C ratio defined the degradation tendency after principal component analysis. The cation exchange capacity and water and alkali solubility presented the highest loading factors for the characterization of fungal transformation of beech wood.
Offprint requests to: A. T. Martínez 相似文献
19.
Natsuki Osaka Yu kanesaki Megumi Watanabe Satoru Watanabe Taku Chibazakura Hiraku Takada Hirofumi Yoshikawa Kei Asai 《Molecular microbiology》2020,113(6):1155-1169
In bacteria, guanosine (penta)tetra-phosphate ([p]ppGpp) is essential for controlling intracellular metabolism that is needed to adapt to environmental changes, such as amino acid starvation. The (p)ppGpp0 strain of Bacillus subtilis, which lacks (p)ppGpp synthetase, is unable to form colonies on minimal medium. Here, we found suppressor mutations in the (p)ppGpp0 strain, in the purine nucleotide biosynthesis genes, prs, purF and rpoB/C, which encode RNA polymerase core enzymes. In comparing our work with prior studies of ppGpp0 suppressors, we discovered that methionine addition masks the suppression on minimal medium, especially of rpoB/C mutations. Furthermore, methionine addition increases intracellular GTP in rpoB suppressor and this effect is decreased by inhibiting GTP biosynthesis, indicating that methionine addition activated GTP biosynthesis and inhibited growth under amino acid starvation conditions in (p)ppGpp0 backgrounds. Furthermore, we propose that the increase in intracellular GTP levels induced by methionine is due to methionine derivatives that increase the activity of the de novo GTP biosynthesis enzyme, GuaB. Our study sheds light on the potential relationship between GTP homeostasis and methionine metabolism, which may be the key to adapting to environmental changes. 相似文献
20.
Efficient production of menaquinone (vitamin K2) by a menadione-resistant mutant of Bacillus subtilis 总被引:1,自引:0,他引:1
T Sato Y Yamada Y Ohtani N Mitsui H Murasawa S Araki 《Journal of industrial microbiology & biotechnology》2001,26(3):115-120
Efficient production of menaquinone (MK) by Bacillus subtilis was achieved. An edible strain of B. subtilis, isolated from the traditional Japanese food natto, was mutated to improve MK productivity. A menadione-resistant mutant
producing 30% more MK than its parent strain was obtained. Soybean extract and glycerol were the best nitrogen and carbon
sources, respectively, among the sources tested. Addition of yeast extract also increased MK productivity. The maximum concentration
of MK reached about 35.0 mg/l after 4 days of culture in a jar fermenter. The pH of the medium decreased to 5.5 after the
start of cultivation, then spontaneously increased to 7.7–8.0. This pH change might be important in the production of MK because
only small amounts of MK were obtained when pH was controlled at 5.7, 6.0, 7.0, 7.5 or 8.0. Journal of Industrial Microbiology & Biotechnology (2001) 26, 115–120.
Received 24 April 2000/ Accepted in revised form 14 August 2000 相似文献