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Plates of mixed greens salads have become fundamental piece of individuals' eating routine all around the globe. They are normally consumed raw and with no treatment or careful washing; henceforth they have been accounted for to become vehicles for the transmission of pathogenic microorganism related with human diseases. Therefore, in present study fresh samples of salads consisting of various fruits and vegetable salads were collected from different areas in vicinity Maharishi Markandeshwar (Deemed to be University), Mullana-Ambala (HR), India and evaluated for bacterial loads using standard microbiological techniques. Most of samples showed presence of high amount mesophillic bacteria. Some samples further showed the presence of pathogens like Escherichia coli, Salmonella spp. and Staphylococcus spp., which were confirmed by using various biochemical test like triple sugar iron test, catalase test and sugar fermentation test etc. Most of microorganisms were found to be susceptible towards various antibiotics used in the study. The study may be helpful to policy makers in planning of food safety and health security in future for food borne disease free livelihood, sustainable development, economy and mankind. [ABSTRACT FROM AUTHOR]

This study was conducted to isolate and identify lactobacilli from larval and adult midgut of wild Aedes aegypti (Ae. aegypti) to find candidate bacteria for paratransgenic control. Characterization of the bacterial symbionts was done using Gram staining, motility test, catalase test, and biochemical tests, among others, and the morphological features were confirmed using a standard scheme that simplifies the identification of lactic acid bacteria. A total of 174 strains were isolated and identified, 135 strains from larval midgut and 39 strains from adult midgut (mean ± SE, 4.00 ± 0.72; P = 0.00). The isolated species were confirmed to be Lactobacillus fermentum, L. casei, L. acidophilus, L. viridescens, L. brevis and L. gasseri. It can be concluded that Ae. aegypti has the potential of harboring the cultivable bacterial symbionts. In conclusion, the isolated species were nominated for paratransgenic control, particularly L. fermentum, being found in large numbers from both larval and adulxt midgut. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate whether oxidative stress occurs in rats experimentally infected by Sporothrix schenckii, and its possible effect on disease pathogenesis. Thirty rats were divided into two groups: the group A (uninfected, n = 18) and the group B (infected by S. schenckii, n=21). Blood samples were collected on days 15, 30 and 40 post-infection (PI). At each sampling time, six rats of the group A, and seven of the group B were bled. TBARS (thiobarbituric acid reactive substances) levels in serum samples were measured to evaluate lipid peroxidation. In addition, catalase (CAT) and superoxide dismutase (SOD) activities, known as biomarkers of antioxidants levels, were verified in whole blood. Seric pro-inflammatory cytokine levels were measured (IFN-γ, TNF-α, and IL-6), which showed that these inflammatory mediators were at higher levels in the infected rats (P < 0.001). In comparison to uninfected animals, rats with sporotrichosis showed significantly higher (p < 0.01) levels of TBARS on day 40 PI; CAT activity was significantly increased (p < 0.01) on days 30 and 40 PI; and SOD activity was increased (p < 0.01) on day 40 PI. Infected rats showed larger testicles and granulomas in the testicular capsule, as well as hepatic granulomas and splenic follicular hyperplasia. All tissues (testicle, spleen, and liver) showed inflammation associated with numerous fungal structures. These results demonstrated that the intense inflammatory response (seric and tissue) in sporotrichosis is a likely mechanism for redox imbalance, and consequently cause the oxidative stress in experimentally infected rats. [ABSTRACT FROM AUTHOR]

The current study elucidates the responses of a typical ornamental plant Mirabilis jalapa to exhausted engine oil (EEO) during phytoremediation. Greenhouse experiments were established to assess the plant's response in terms of germination, biomass, chlorophyll content, superoxide dismutase (SOD) activity, catalase activity, soluble protein content, and hydrocarbon degradation at different concentrations of EEO (0.5 to 15 mL). Results illustrate that the increasing concentration of EEO reduced plant growth, whose responses were further confirmed by decreased chlorophyll content (chlorophyll a and b), high superoxide dismutase activity, lowered catalase activity, and reduced soluble protein content. Although the germination rate was successful in all the treatments, we observed a significant reduction in biomass - especially the elongation inhibition rate (>48.4%) - at EEO concentrations higher than 2%. Conclusively, the high toxicity index (40.4% to 93.3%) and lesser hydrocarbons degradation (36% to 10.8%) render the plant species unsuitable for future EEO phytoremediation experiments. [ABSTRACT FROM AUTHOR]

Introduction: Bacterial vaginosis (BV) is a syndrome related to Gardnerella vaginalis and is characterized by an imbalance in the vaginal microbiota. This work focused on the evaluation of antimicrobial susceptibility patterns and the occurrence of the vaginolysin (vly) gene in G. vaginalis isolated from BV and non-BV patients. Methodology: The vaginal secretions were collected randomly and processed for G. vaginalis isolation. The isolates were presumptively identified by β-hemolysis and oxidase and catalase tests. Polymerase chain reaction (PCR) was performed to confirm bacterial identity and to detect the vly gene. Antimicrobial susceptibility patterns were determined. Results: Of 89 patients, G. vaginalis was isolated from 42 (37 BV and 5 non-BV), and 204 isolates were selected (179 from BV and 25 non- BV). The vly gene was detected in all G. vaginalis isolated from non-BV women and in 98.3% of the bacteria from BV patients. High resistance was observed for ampicillin (54.4%), metronidazole (59.8%), tinidazole (60.3%) and secnidazole (71.6%). Conclusions: Further studies are needed to better address the role of G. vaginalis and the vly gene in BV pathogenesis. [ABSTRACT FROM AUTHOR]

The article discusses the laboratory based cross-sectional study in a tertiary care hospital in Assam, India, related to drug resistance in Enterococcus. Topics discussed include the identification of genus Enterococcus through Gram stain, catalase test, and hydrolysis of bile-esculin, penicillin and ampicillin resistance has been also reported from north India, and catheterized patients to have urinary tract infection may be of nosocomial nature.

The exposure of Xanthomonas campestris pv. campestris to sublethal concentrations of a sodium hypochlorite (NaOCl) solution induced the expression of genes that encode peroxide scavenging enzymes within the OxyR and OhrR regulons. Sensitivity testing in various X. campestris mutants indicated that oxyR, katA, katG, ahpC, and ohr contributed to protection against NaOCl killing. The pretreatment of X. campestris cultures with oxidants, such as hydrogen peroxide (H2O2), t-butyl hydroperoxide, and the superoxide generator menadione, protected the bacteria from lethal concentrations of NaOCl in an OxyR-dependent manner. Treating the bacteria with a low concentration of NaOCl resulted in the adaptive protection from NaOCl killing and also provided cross-protection from H2O2 killing. Taken together, the results suggest that the toxicity of NaOCl is partially mediated by the generation of peroxides and other reactive oxygen species that are removed by primary peroxide scavenging enzymes, such as catalases and AhpC, as a part of an overall strategy that protects the bacteria from the lethal effects of NaOCl. [ABSTRACT FROM AUTHOR]

Herein, we report on the purification, characterization, and sequencing of catalase from Acinetobacter gyllenbergii 2P01AA, an extremely oxidation-resistant bacterium that was isolated from the Mars Phoenix spacecraft assembly facility. The Acinetobacter are dominant members of the microbial communities that inhabit spacecraft assembly facilities and consequently may serve as forward contaminants that could impact the integrity of future life-detection missions. Catalase was purified by using a 3-step chromatographic procedure, where mass spectrometry provided respective subunit and intact masses of 57.8 and 234.6 kDa, which were consistent with a small-subunit tetrameric catalase. Kinetics revealed an extreme pH stability with no loss in activity between pH 5 and 11.5 and provided respective kcat/ Km and kcat values of ∼107 s−1 M−1 and 106 s−1, which are among the highest reported for bacterial catalases. The amino acid sequence was deduced by in-depth peptide mapping, and structural homology suggested that the catalases from differing strains of A. gyllenbergii differ only at residues near the subunit interfaces, which may impact catalytic stability. Together, the kinetic, alkali-tolerant, and halotolerant properties of the catalase from A. gyllenbergii 2P01AA are significant, as they are consistent with molecular adaptations toward the alkaline, low-humidity, and potentially oxidizing conditions of spacecraft assembly facilities. Therefore, these results support the hypothesis that the selective pressures of the assembly facilities impact the microbial communities at the molecular level, which may have broad implications for future life-detection missions. Key Words: Catalase-Kinetics-Sequence-Stability- Acinetobacter-Spacecraft-Planetary protection. Astrobiology 15, 291-300. [ABSTRACT FROM AUTHOR]

The present study aimed to isolate and select bacteria with cellulolytic capacity, having future application as inoculum in the fibrous organic waste composting. Five sampling environments were considered: organic agriculture (AO), conventional agriculture (AQ), forest (BM); sugarcane area (RC) and compost piles (AC). For bacterial isolation the nutrient agar medium was used changing the carbon source by cellulose. The main selection criterion of the bacterial isolates was the growth on above medium and its positive reaction to congo red test, showing clear zones around the colonies. The 93 bacterial isolates obtained were subjected to Gram staining, catalase test, presence of endospores and aerobically growth; having 70 bacteria Bacillus spp. like characteristics. Their cellulolytic activities were determined and 30 bacteria produced hydrolysis halo. Eight of these bacterial isolates were selected according to the largest halo production (AO-19, AO-28, AO-29, AQ-2, BM-7, RC-2, RC-6, CR-18) and their growth at different pH (3, 5, 7, 9) and temperatures (50 and 70 °C) were evaluated. The bacteria AO-19 showed higher hydrolysis halo with 12,33 mm and growth stability at different pH and temperature levels, for which its growth dynamic and amylolytic and pectinolytic capacity was determined. According to results the bacteria AO-19 has potential to be used as inoculum in composting. [ABSTRACT FROM AUTHOR]

Background and Objective: Methicillin-resistant Staphylococcus aureus is a common pathogen responsible for health-care-related infections. This study was done to determine the prevalence of Meticilin - resistant Staphylococcus isolated from hand and nasal of hospital health worker. Methods: This descriptive study was conducted on 148 health workers in teaching hospitals in Sari, northern Iran during 2011-12. Samples were collected from fingers and noses and were cultured on mannitol salt agar immediately. Suspected colonies were identified using Gram staining, catalase and coagulase tests. Susceptibility testing was performed by disk diffusion method. Methicillin resistant strains were determined using micro dilution broth method. Results: Staphylococcus aureus was observed in 24 (16.2%) of individuals. 9.5% of population was resistant to Methicillin. The high portions of Staphylococcus aureus carreier were in the operation room, angiography and internal pediatric ward health worker. Methicillin Staphylococcus aureus resistanat were more common in nasal samples of the operation room personal and angiography ward health worker. All strains were sensitive to Vancomycin and Chloramphenicol and resistant to Penicillin and Amoxicillin. Conclusion: In this study the prevalence of the Staphylococcus.aureus in teaching hospitals health worker was low while Staphylococcus aureus resistant to methicillin was higher than other reports in Iran. [ABSTRACT FROM AUTHOR]

Highlights: [•] Efficacy of R. paludigenum from chitin-added media against P. expansum was enhanced. [•] R. paludigenum from chitin-added media proliferated faster in apple wounds. [•] R. paludigenum from chitin-added media enhanced the resistance in apple fruit. [•] SOD and CAT activities of R. paludigenum from chitin-added media were stimulated. [ABSTRACT FROM AUTHOR]

Reduced mechanical loading during bedrest, spaceflight, casting, etc. causes rapid morphological changes in skeletal muscle: fiber atrophy and reduction of slow-twitch fibers. An emerging signaling event in response to unloading is the translocation of neuronal nitric oxide synthase (nNOSµ) from the sarcolemma to the cytosol. We used EUK-134, a cell-permeable mimetic of superoxide dismutase and catalase, to test the role of redox signaling in nNOSµ translocation and muscle fiber atrophy as a result of short-term (54 hours) hindlimb unloading. Fischer-344 rats were divided into ambulatory controls (CON), hindlimb unloaded (HU), and hindlimb unloaded + EUK-134 (HU-EUK) groups. EUK-134 mitigated the unloading-induced phenotype, including muscle fiber atrophy and muscle fiber-type shift from slow to fast. nNOSµ immunolocalization at the sarcolemma of the soleus was reduced with HU, while nNOSµ protein content in the cytosol increased with unloading. Translocation of nNOS from the sarcolemma to cytosol was virtually abolished by EUK-134. EUK-134 also mitigated dephosphorylation at Thr32 of FoxO3a during HU. Hindlimb unloading elevated oxidative stress (4-hydroxynonenal) and increased sarcolemmal localization of Nox2 subunits gp91phox (Nox2) and p47phox, effects normalized by EUK-134. Thus, our findings are consistent with the hypothesis that oxidative stress triggers nNOSµ translocation from the sarcolemma and FoxO3a dephosphorylation as an early event during mechanical unloading. Thus redox signaling may serve as a biological switch for nNOS to initiate morphological changes in skeletal muscle fibers. [ABSTRACT FROM AUTHOR]

A mesophilic, obligately anaerobic, propionate-producing fermentative bacterium, designated strain NM7, was isolated from rural rice paddy field. Cells of strain NM7 are Gram-negative, non-motile, non-spore-forming, short rods, and negative for catalase. The strain grew optimally at 37 °C (the range for growth 15-40 °C) and pH 7.0 (pH 5.0-7.5). The strain could grow fermentatively on various sugars, including arabinose, xylose, fructose, galactose, glucose, mannose, cellobiose, lactose, maltose, sucrose, pectin and starch. The main end products of glucose fermentation were acetate and propionate. Yeast extract was not required but stimulated the growth. Nitrate, sulfate, thiosulfate, elemental sulfur, sulfite, and Fe(III) nitrilotriacetate were not used as terminal electron acceptors. The G+C content of genomic DNA was 42.8 mol%. The major cellular fatty acids were C, anteiso-C, C, and C. The most abundant polar lipid of strain NM7 was phosphatidylethanolamine. 16S rRNA gene sequence analysis revealed that it belongs to the family Porphyromonadaceae of the phylum Bacteroidetes. The closest recognized species was Paludibacter propionicigenes (91.4 % similarity in 16S rRNA gene sequence). A novel species, Paludibacter jiangxiensis sp. nov., is proposed to accommodate strain NM7 (=JCM 17480 = CGMCC 1.5150 = KCTC 5844). [ABSTRACT FROM AUTHOR]

Small heat shock proteins encompass a widespread but diverse class of proteins, which play key roles in protecting organisms from various stressors. In the present study, the full-length cDNAs of two small heat shock proteins (MgsHSP22 and MgsHSP24.1) were cloned from Mytilus galloprovincialis, which encoded peptides of 181 and 247 amino acids, respectively. Both MgsHSP22 and MgsHSP24.1 were detected in all tissues examined by real-time PCR, with the highest expression being observed in muscle and gonad tissues. The real-time PCR results revealed that Cd significantly inhibited MgsHSP22 expression at 24 h and MgsHSP24.1 at 24 and 48 h under 5 μg/L Cd exposure. MgsHSP24.1 expression was also significantly inhibited after 50 μg/L Cd exposure for 48 h. With regard to antioxidant enzymes, increased GPx and CAT activity were detected under Cd stress (5 and 50 μg/L), while no significant difference in SOD activity was observed throughout the experiment. Overall, both MgsHsps and antioxidant enzymes revealed their potential as Cd stress biomarkers in M. galloprovincialis. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa (PA) is a common bacterial pathogen, responsible for a high incidence of nosocomial and respiratory infections. KatA is the major catalase of PA that detoxifies hydrogen peroxide (H2O2), a reactive oxygen intermediate generated during aerobic respiration. Paradoxically, PA displays elevated KatA activity under anaerobic growth conditions where the substrate of KatA, H2O2, is not produced. The aim of the present study is to elucidate the mechanism underlying this phenomenon and define the role of KatA in PA during anaerobiosis using genetic, biochemical and biophysical approaches. We demonstrated that anaerobic wild-type PAO1 cells yielded higher levels of katA transcription and expression than aerobic cells, whereas a nitrite reductase mutant ΔnirS produced ∼50% the KatA activity of PAO1, suggesting that a basal NO level was required for the increased KatA activity. We also found that transcription of the katA gene was controlled, in part, by the master anaerobic regulator, ANR. A ΔkatA mutant and a mucoid mucA22 ΔkatA bacteria demonstrated increased sensitivity to acidified nitrite (an NO generator) in anaerobic planktonic and biofilm cultures. EPR spectra of anaerobic bacteria showed that levels of dinitrosyl iron complexes (DNIC), indicators of NO stress, were increased significantly in the ΔkatA mutant, and dramatically in a ΔnorCB mutant compared to basal levels of DNIC in PAO1 and ΔnirS mutant. Expression of KatA dramatically reduced the DNIC levels in ΔnorCB mutant. We further revealed direct NO-KatA interactions in vitro using EPR, optical spectroscopy and X-ray crystallography. KatA has a 5-coordinate high spin ferric heme that binds NO without prior reduction of the heme iron (Kd ∼6 μM). Collectively, we conclude that KatA is expressed to protect PA against NO generated during anaerobic respiration. We proposed that such protective effects of KatA may involve buffering of free NO when potentially toxic concentrations of NO are approached. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa (PA) is a common bacterial pathogen, responsible for a high incidence of nosocomial and respiratory infections. KatA is the major catalase of PA that detoxifies hydrogen peroxide (H2O2), a reactive oxygen intermediate generated during aerobic respiration. Paradoxically, PA displays elevated KatA activity under anaerobic growth conditions where the substrate of KatA, H2O2, is not produced. The aim of the present study is to elucidate the mechanism underlying this phenomenon and define the role of KatA in PA during anaerobiosis using genetic, biochemical and biophysical approaches. We demonstrated that anaerobic wild-type PAO1 cells yielded higher levels of katA transcription and expression than aerobic cells, whereas a nitrite reductase mutant ΔnirS produced ∼50% the KatA activity of PAO1, suggesting that a basal NO level was required for the increased KatA activity. We also found that transcription of the katA gene was controlled, in part, by the master anaerobic regulator, ANR. A ΔkatA mutant and a mucoid mucA22 ΔkatA bacteria demonstrated increased sensitivity to acidified nitrite (an NO generator) in anaerobic planktonic and biofilm cultures. EPR spectra of anaerobic bacteria showed that levels of dinitrosyl iron complexes (DNIC), indicators of NO stress, were increased significantly in the ΔkatA mutant, and dramatically in a ΔnorCB mutant compared to basal levels of DNIC in PAO1 and ΔnirS mutant. Expression of KatA dramatically reduced the DNIC levels in ΔnorCB mutant. We further revealed direct NO-KatA interactions in vitro using EPR, optical spectroscopy and X-ray crystallography. KatA has a 5-coordinate high spin ferric heme that binds NO without prior reduction of the heme iron (Kd ∼6 μM). Collectively, we conclude that KatA is expressed to protect PA against NO generated during anaerobic respiration. We proposed that such protective effects of KatA may involve buffering of free NO when potentially toxic concentrations of NO are approached. [ABSTRACT FROM AUTHOR]

This study was carried out for the characterization and discrimination of the indigenous Gram positive, catalase-positive cocci (GCC) population in sucuk, a traditional Turkish dry-fermented sausage. Sucuk samples, produced by the traditional method without starter culture were collected from 8 local producers in Kayseri/Turkey and a total of 116 GCC isolates were identified by using different molecular techniques. Two different molecular fingerprinting methods; namely, randomly amplified polymorphic DNA-PCR (RAPD-PCR) and repetitive extragenic palindrome-PCR (rep-PCR), were used for the clustering of isolates and identification at species level was carried out by full length sequencing of 16S rDNA. Combining the results obtained from molecular fingerprinting and 16S rDNA sequencing showed that the dominant GCC species isolated from the sucuk samples was Staphylococcus saprophyticus followed by Staphylococcus succinus and Staphylococcus equorum belonging to the Staphylococcus genus. Real-time PCR DNA melting curve analysis and high-resolution melting (HRM) analysis targeting the V1 + V3 regions of 16S rDNA were also applied for the discrimination of isolates belonging to different species. It was observed statistically different Tm values and species-specific HRM profiles for all except 2 species ( S. saprophyticus and Staphylococcus xylosus) that have high 16S rDNA sequence similarity. The combination of rep-PCR and/or PCR-RAPD with 16S rRNA gene sequencing was an efficient approach for the characterization and identification of the GCC population in spontaneously fermented sucuk. On the other hand, intercalating dye assays were found to be a simple and very promising technique for the differentiation of the GCC population at species level. [ABSTRACT FROM AUTHOR]

Biofilm formation of Campylobacter jejuni, a major cause of human gastroenteritis, contributes to the survival of this pathogenic bacterium in different environmental niches; however, molecular mechanisms for its biofilm formation have not been fully understood yet. In this study, the role of oxidative stress resistance in biofilm formation was investigated using mutants defective in catalase (KatA), superoxide dismutase (SodB), and alkyl hydroperoxide reductase (AhpC). Biofilm formation was substantially increased in an ahpC mutant compared to the wild type, and katA and sodB mutants. In contrast to the augmented biofilm formation of the ahpC mutant, a strain overexpressing ahpC exhibited reduced biofilm formation. A perR mutant and a CosR-overexpression strain, both of which upregulate ahpC, also displayed decreased biofilms. However, the introduction of the ahpC mutation to the perR mutant and the CosR-overexpression strain substantially enhanced biofilm formation. The ahpC mutant accumulated more total reactive oxygen species and lipid hydroperoxides than the wild type, and the treatment of the ahpC mutant with antioxidants reduced biofilm formation to the wild-type level. Confocal microscopy analysis showed more microcolonies were developed in the ahpC mutant than the wild type. These results successfully demonstrate that AhpC plays an important role in the biofilm formation of C. jejuni. [ABSTRACT FROM AUTHOR]

Biofilm formation of Campylobacter jejuni, a major cause of human gastroenteritis, contributes to the survival of this pathogenic bacterium in different environmental niches; however, molecular mechanisms for its biofilm formation have not been fully understood yet. In this study, the role of oxidative stress resistance in biofilm formation was investigated using mutants defective in catalase (KatA), superoxide dismutase (SodB), and alkyl hydroperoxide reductase (AhpC). Biofilm formation was substantially increased in an ahpC mutant compared to the wild type, and katA and sodB mutants. In contrast to the augmented biofilm formation of the ahpC mutant, a strain overexpressing ahpC exhibited reduced biofilm formation. A perR mutant and a CosR-overexpression strain, both of which upregulate ahpC, also displayed decreased biofilms. However, the introduction of the ahpC mutation to the perR mutant and the CosR-overexpression strain substantially enhanced biofilm formation. The ahpC mutant accumulated more total reactive oxygen species and lipid hydroperoxides than the wild type, and the treatment of the ahpC mutant with antioxidants reduced biofilm formation to the wild-type level. Confocal microscopy analysis showed more microcolonies were developed in the ahpC mutant than the wild type. These results successfully demonstrate that AhpC plays an important role in the biofilm formation of C. jejuni. [ABSTRACT FROM AUTHOR]

The aim of this study was comparison different methods of species identification of enterococci. One hundred and fifty three suspected colonies were isolated from milk and dairy products (cheeses from cow's, ewe's and goat's milk). On the bases of their growth on BEA agar, microscopic characteristic, results of Gram staining, catalase test and PYRAtest was thirty four isolates assigned to the genus Enterococcus. These isolates were identified by commercial biochemical test EN-COCCUS. 52.9% of them were included in species E. faecalis, 29.4% in E. faecium, 14.7% in E. durans and 2.9% in E. group III. This group includes 3 species: E. durans, E. hirae, E. faecalis asaccharolytic var. Then 16S rRNA sequencing nucleotide of all isolates was realized. Results of sequencing were compared with NCBI database. Only 14.7% of isolates were in 100% accordance. One from them was species E. durans and others were designated as E. faecium. For 20.6% of detected isolates was in accordance with more reference strains. Other isolates were identical with reference strain on 99%. For verification of all results species-specific PCR was used and 52.9% isolates were identified as species E. faecalis, 32.4% as E. faecium and 14.7% as E. durans. Strains belonging to the species E. faecalis were identified the most reliable by all used methods. [ABSTRACT FROM AUTHOR]

Solar ultraviolet radiation is a major environmental factor that has serious adverse effects on the structure and function of the skin. Although the UVB waveband (295–315 nm) represents only 5–10% of incoming UV light, it is very damaging to the skin. The aim of this study was to investigate the effect of Lonicera caerulea berries on UVB-induced damage to SKH-1 hairless mice. Mice were fed a L. caerulea berry-enriched diet (10%, w/w) for 14 days before a single UVB (1000 mJ cm−2) treatment. Effects on health status, antioxidant enzyme activity and expression, and DNA damage were evaluated. The bioavailability of L. caerulea phenolic components was also assessed. We found that feeding with L. caerulea berries prevented a decrease in catalase activity and stimulated NADPH quinone oxidoreductase-1, heme oxygenase-1, and gamma-glutamylcysteine synthetase catalytic and modulatory subunit expression in UVB exposed mice. Administration of the L. caerulea berry-enriched diet led to an increase in UVB-reduced interleukin-17 levels and a decrease in keratinocyte-derived chemokine protein expression that was enhanced after UVB treatment. Further, L. caerulea berries reduced UVB-induced DNA damage evaluated as number of single strand breaks, cyclobutane–pyrimidine dimer formation and H2AX phosphorylation, a marker of double strand breaks. Taken together, we provide evidence that oral administration of L. caerulea berries to mice affords at least partial protection from the adverse effects of a single UVB exposure via modulation of antioxidant enzyme activity/expression and reduction of DNA damage. [ABSTRACT FROM AUTHOR]

The article focuses on a study that was conducted to analyse the effectiveness of Catalases CAT1 and CAT3 in protecting gamma irradiation-induced damage of Arabidopsis thaliana plant. It mentions the procedure where Rosette leaves were exposed to gamma rays and the Catalase activities were measured with the help of comet assay. The result showed the inefficiency of CATl and CAT3 in providing the damage protection.

Abstract: Organic and inorganic forms of mercury are highly neurotoxic environmental contaminants. The exact mechanisms involved in mercury neurotoxicity are still unclear. Oxidative stress appears to play central role in this process. In this study, we aimed to validate an insect-based model for the investigation of oxidative stress during mercury poisoning of lobster cockroach Nauphoeta cinerea. The advantages of using insects in basic toxicological studies include the easier handling, rapid proliferation/growing and absence of ethical issues, comparing to rodent-based models. Insects received solutions of HgCl2 (10, 20 and 40mgL-1 in drinking water) for 7d. 24h after mercury exposure, animals were euthanized and head tissue samples were prepared for oxidative stress related biochemical determinations. Mercury exposure caused a concentration dependent decrease in survival rate. Cholinesterase activity was unchanged. Catalase activity was substantially impaired after mercury treatment 40mgL-1. Likewise, GST had a significant decrease, comparing to control. Peroxidase and thioredoxin reductase activity was inhibited at concentrations of 20mgL-1 and 40mgL-1 comparing to control. These results were accompanied by decreased GSH levels and increased hydroperoxide and TBARS formation. In conclusion, our results show that mercuric compounds are able to induce oxidative stress signs in insect by modulating survival rate as well as inducing impairments on important antioxidant systems. In addition, our data demonstrates for the first time that Nauphoeta cinerea represents an interesting animal model to investigate mercury toxicity and indicates that the GSH and thioredoxin antioxidant systems plays central role in Hg induced toxicity in insects. [Copyright &y& Elsevier]

The present study aimed to compare three identification methods that are routinely used for the detection of Staphylococcus aureus as bovine mastitis agent.The evaluated methods were as followed: conventional biochemical method, commercial identification system BioLog (Gen III MicroPlate) and amplification of species-specific gene (nuc) by polymerase chain reaction (PCR). A total of 73 staphylococcal isolates were collected from 453 individual milk samples from dairy cows with subclinical and clinical mastitis from different farms in Bulgaria. This isolates were determined as 60 coagulase-positive, 3 catalase-negative and 10 coagulase-negative by conventional methods. BioLog system identified 72 isolates as 5. aureus subsp. aureus and one coagulase-positive isolate as 5. schleiferi subsp. coagulans. PCR amplification of nuc gene further confirmed S. aureus subsp. aureus isolates identified by the BioLog system. The primary identification of S. aureus on the basis of coagulase level led to erroneous determination of 14 (19.2%) of the isolates. Based on the findings, BioLog system and PCR appear to be more reliable detection systems for 5. aureus from milk. In conclusion, the present study showed that a routine approach using a combination of phenotypic and molecular detection systems could improve 5.aureus detection in milk. [ABSTRACT FROM AUTHOR]

All methane-producing Archaea (methanogens) are strict anaerobes, but the majority of species are tolerant to oxidants. Methanosarcina species are important environmental and industrial methanogens as they are one of only two genera capable of producing methane with acetate. Importantly, Methanosarcina species appear to be the most oxidant-tolerant; however, the mechanisms underlying this tolerance are poorly understood. We report herein two similar methods (spot-plating and microtiter plate) developed to examine the oxidant tolerance of Methanosarcina acetivorans by viability assessment. Both methods revealed that M. acetivorans can tolerate exposure to millimolar levels of hydrogen peroxide (H2O2) without a complete loss of viability. The exogenous addition of catalase was also shown to protect M. acetivorans from H2O2 toxicity, indicating catalase can serve as an antioxidant enzyme in methanogens even though oxygen is a byproduct. Of the two methods, the microtiter plate method provided a simple, reliable, and inexpensive method to assess viability of M. acetivorans. Combined with recent advances in the genetic manipulation of methanogens, methods in assessment of methanogen oxidant tolerance will aid in the identification of components of the antioxidant defense systems. [ABSTRACT FROM AUTHOR]

Abstract: Novel orange-pigmented, Gram-negative, rod-shaped, non-motile bacteria, designated strains NIO-S3T and NIO-S4, were isolated from a water sample collected from Cochin back waters, Thanneermukkom and Arookutty, Kerala, India. Both strains were positive for oxidase and catalase activities, and hydrolyzed gelatin and Tween 40. The predominant fatty acids were iso-C15:0, anteiso-C15:0, iso-C17:0 3OH, C16:1 ω7c/C16:1 ω6c (summed feature 3) and iso-C17:1 ω9c/C16:0 10-methyl (summed feature 9), whereas MK-7 was the major respiratory quinone, and phosphatidylethanolamine, two unidentified phospholipids and one unidentified lipid were the only polar lipids. The DNA G+C content of the two strains was 43.7 and 43.6mol%, respectively. The 16S rRNA gene sequence analysis indicated that they were members of the genus Algoriphagus and closely related to Algoriphagus olei CC-Hsuan-617T, Algoriphagus aquatilis A8-7T, Algoriphagus aquaeductus LMG 24398T and Algoriphagus mannitolivorans DSM 15301T, with pairwise sequence similarities of 96.8, 96.6, 96.2 and 96.2%, respectively. DNA–DNA hybridization between strains NIO-S3T and NIO-S4 showed a relatedness of 89%. Based on data from the current polyphasic study, the strains are proposed as a novel species of the genus Algoriphagus, for which the name Algoriphagus shivajiensis sp. nov. is proposed. The type strain of A. shivajiensis is NIO-S3T (=JCM 17885T =MTCC 11066T). [Copyright &y& Elsevier]

CosR is an essential response regulator in Campylobacter jejuni, a major food-borne pathogen causing enteritis worldwide. A transcriptomic analysis performed in this study discovered 93 genes whose transcriptional levels were changed >2-fold due to the repression of CosR expression by antisense peptide nucleic acid. The identified CosR-regulated genes are involved in various cellular functions, such as energy production, protein synthesis and folding, flagellum biogenesis, and lipid metabolism. Interestingly, 17 of the 93 CosR-regulated genes (18.3%) are predicted essential genes, indicating that CosR may participate in the regulation of vital biological processes in C. jejuni. In particular, CosR knockdown increased the transcriptional levels of cmeA, cmeB, and cmeC genes, whose protein product (CmeABC) is an important determinant conferring multidrug resistance in Campylobacter. Negative regulation of cmeABC by CosR was verified by quantitative real-time PCR (qRT-PCR) and PcmeABC::lacZ assay. The results of electrophoretic mobility shift assays (EMSAs) and DNase I footprinting assays demonstrated that CosR directly binds to the cmeABC promoter. Another notable finding is that CosR regulates the transcription of katA, the sole catalase gene in C. jejuni. Further characterization with qRT-PCR, the catalase enzyme assay, EMSA, and DNase I footprinting assays successfully demonstrated that CosR affects the katA transcription and the catalase activity by direct interactions with the katA promoter. The findings in this study clearly demonstrated that CosR regulates resistance mechanisms in C. jejuni by controlling the expression of genes involved in oxidative stress defense and extrusion of toxic compounds out of the cell. [ABSTRACT FROM AUTHOR]

The article presents the findings of a research conducted on examining the fermented mare milk to explore potential probiotics in the traditional foods of Indonesia. It discusses the methodology used in conducting the research including gram staining, catalase activity and cell morphology. The research reveals that all the isolates identified as lactobacilli as they appeared as Gram-positive rods without catalase activity.

Two high protein wheat flour samples of Red Horse (RH) and Bake with Yen (BY) were examined for predominant Lactobacillus spp. in fermented liquid sourdough. The identification of Lactobacillus spp. was based on biochemical tests of catalase test, gas carbon dioxide production, arginine test, the ability to grow at temperature of 15°C and 45°C and carbohydrate fermentation using API50CH kit. Those strains were identified as Lactobacillus spp. and confirmed using polymerase chain reaction (PCR) of 16S rRNA partial sequencing analysis. In the present study, we successfully isolated and identified the Lactobacillus plantarum and L. fermentum which were predominant bacteria in liquid sourdough of the sample RH and BY brand, respectively. [ABSTRACT FROM AUTHOR]

Marine gastropods, exposed to anthropogenic pollution, accumulate high chemical concentrations in their tissues, especially in the digestive glands. An evaluation of the impacts of cadmium (Cd) and permethrin (Perm), coupled with reproductive events (pre-spawning and post-spawning phase) throughout the year, was attempted by measuring catalase (CAT), a biomarker of defence, on Hexaplex trunculus experimentally exposed for 48 or 96 h. Specimens of gastropods were sampled from Bizerta Lagoon (Tunisia). The results show that CAT activity increased in gastropods exposed to the three cadmium concentrations (C1 Cd, 100 μg L; C2 Cd, 200 μg L; and C3 Cd, 300 μg L) and to the three permethrin doses (C1 Perm, 100 μg L; C2 Perm, 150 μg L; and C3 Perm, 200 μg L) tested. A decrease in CAT was noted in the digestive gland of the H. trunculus exposed to permethrin at the concentration of 200 μg L during the pre-spawning and post-spawning phases. H. trunculus in post-spawning was more sensitive to cadmium and permethrin than in the pre-spawning phase. The biochemical responses to pollutants (cadmium and permethrin) represented by CAT may act as a biomarker of exposure in this species. [ABSTRACT FROM AUTHOR]

Different types and concentrations of probiotics were evaluated for their effects on growth, survival and enzyme activity of hatchery-reared N odipecten subnodosus spat. The treatments included (1) a mix of the microalgae I sochrysis galbana and P avlova salina as the control group; (2) Diet 1 + a mix of B urkholderia cepacia and P seudomonas aeruginosa; (3) Diet 1 + the commercial probiotic Epicin; and (4) Diet 1 + the commercial probiotic Bactosafe. Both commercial probiotics were tested at 3, 6 and 10 mg L−1. Scallops receiving Bactosafe and Epicin at 3 and 6 mg L−1 grew ~30% faster and larger than in the control group. Regardless of the treatment, survival at the end was 98.7%. There was no relation between the activity of catalase and superoxide dismutase; however, significantly lower catalase levels occurred at increasing doses of Epicin; significant higher catalase levels occurred in the control group and mix of bacilli. Compared with the control group, lysozyme levels were significantly higher with the Epicin and Bactosafe treatments (3 and 6 mg L−1). More research needs to be conducted with probiotics to determine their real effects on the activity of antioxidant enzymes. We expect that treated scallops will increase their performance at the field. [ABSTRACT FROM AUTHOR]

Abstract: Novel orange pigmented, Gram-negative-staining, rod-shaped, non-motile, strictly aerobic strains designated NIO-S1T and NIO-S2 were isolated from the water sample of a pond adjacent to the coast and an algal mat from a fish pond, respectively, at Kakinada, India. Both strains were positive for oxidase, catalase and β-galactosidase activities. The predominant fatty acids in NIO-S1T were iso-C15:0 (39.6%), anteiso-C15:0 (9.9%), iso-C17:0 3OH (10.9%) and C16:1 ω7c/C16:1 ω6c (summed feature 3) (5.7%). The strains contained MK-7 as the major respiratory quinine, and diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and three unidentified lipids as the polar lipids. Phylogenetic analysis indicated that strain NIO-S1T was a member of the family “Cyclobacteriaceae” of the class “Sphingobacteriia” and it clustered with the genera Fontibacter, Cecembia and Aquiflexum with phylogenetic distances of 6.8, 9.0 and 12.2% (93.2, 91.0 and 87.8% similarity), respectively. DNA–DNA hybridization between strains NIO-S1T and NIO-S2 showed a relatedness of 93% and rep-PCR banding patterns were similar. Based on data from the current polyphasic study, it is proposed that the new isolates be placed in a new genus and species with the name Shivajiella indica gen. nov., sp. nov. The type strain of Shivajiella indica is NIO-S1T (= KCTC 19812T =MTCC 11065T). [Copyright &y& Elsevier]

Abstract: Three pale-orange bacteria (strains 1083-08, 1084-08T and 1095B-08) were isolated from diseased rainbow trout. The isolates were Gram-staining-negative, catalase- and oxidase-positive, rod-shaped cells. Analyses of their 16S rRNA gene sequences confirmed their adscription to the genus Chryseobacterium. The three isolates shared 100% 16S rRNA gene sequence similarity and 98.5% similarity with Chryseobacterium indologenes CCUG 14556T, being the closest phylogenetically related species. Genomic DNA–DNA hybridization similarity values between the three isolates were 94–100% and 2–39% between strain 1084-08T and the type strains of other related Chryseobacterium species, confirming that the isolates represent a novel species within the genus Chryseobacterium. The DNA G+C content of the species was 33.6–36.1mol%. The predominant respiratory quinone of strain 1084-08T was MK-6 and the major fatty acids were iso-C15:0, iso-C17:1 ω9c, iso-C17:0 3-OH and C16:1 ω6c. The isolates were distinguished from related Chryseobacterium species by a number of phenotypic properties. Based on the phenotypic, genotypic and phylogenetic findings, it is proposed that the new isolates from rainbow trout be classified as a new species of the genus Chryseobacterium, with the name of Chryseobacterium tructae sp. nov. The type strain is 1084-08T (=CECT 7798T =CCUG 60111T). [Copyright &y& Elsevier]

This study explored the level of infection caused by different inoculum concentrations (10², 10³, and 104 zoospores mL-1) of Phytophthora capsici in 3 pepper cultivars at days 2, 4, and 6. The effect that the infection induced on the peroxidase (POX), catalase (CAT), and phenolics of resistant and sensitive seedlings, as well as the defense mechanism against the pathogen, were also investigated. The resistance of PM-702 against the isolate used was high, whereas KM-Hot and DEM-8 displayed sensitive reactions. As a result of analyses of the leaves and stems from the 3 pepper cultivars, important changes in biochemical parameters were observed between resistant and sensitive cultivars after inoculation with the root rot pathogen P. capsici. The maximum increase of POX and CAT was observed in the resistant PM-702 cultivar. However, with a high inoculum concentration (104 zoospores mL-1), a loss of CAT activity was determined, especially in susceptible cultivars. The maximum increase in phenolics was detected in leaves of susceptible DEM-8 and stems of PM-702 on day 6 following infection. The results suggest that during Phytophthora root rot development there is a relation between the disease induced by P. capsici and the antioxidant system. [ABSTRACT FROM AUTHOR]

Summary: Iron (Fe) chlorosis is a common nutritional deficiency in fruit trees grown in calcareous soils. Grafting on tolerant rootstocks is the most efficient practice to cope with it. In the present work, three Prunus hybrid genotypes, commonly used as peach rootstocks, and one peach cultivar were cultivated with bicarbonate in the growth medium. Parameters describing oxidative stress and the metabolism of reactive nitrogen species were studied. Lower contents of nitric oxide and a decreased nitrosoglutathione reductase activity were found in the most sensitive genotypes, characterized by higher oxidative stress and reduced antioxidant defense. In the peach cultivar, which behaved as a tolerant genotype, a specifically nitrated polypeptide was found. [ABSTRACT FROM AUTHOR]

Abstract: Acetylation of lysine residues is conserved in all three kingdoms; however, its role in prokaryotes is unknown. Here we demonstrate that acetylation enables the reference bacterium Escherichia coli to withstand environmental stress. Specifically, the bacterium reaches higher cell densities and becomes more resistant to heat and oxidative stress when its proteins are acetylated as shown by deletion of the gene encoding acetyltransferase YfiQ and the gene encoding deacetylase CobB as well as by overproducing YfiQ and CobB. Furthermore, we show that the increase in oxidative stress resistance with acetylation is due to the induction of catalase activity through enhanced katG expression. We also found that two-component system proteins CpxA, PhoP, UvrY, and BasR are associated with cell catalase activity and may be responsible as the connection between bacterial acetylation and the stress response. This is the first demonstration of a specific environmental role of acetylation in prokaryotes. [Copyright &y& Elsevier]

Background: Most monoclonal antibody-based stool antigen tests are of the 'send-out' format. Rapid Testmate pylori antigen (Rapid TPAg) uses monoclonal antibody and is an 'in-the-office' test. The aim of this study was to examine the usefulness of Rapid TPAg for the management of H. pylori infection. Methods: One-hundred and two consecutive patients who received H. pylori eradication therapy underwent both urea breath test (UBT) and Rapid TPAg at 5-6 weeks after finishing the eradication therapy. Stool samples were maintained at −20, 5, 25, and 40°C and subjected to Rapid TPAg after 1-7 days. Stool samples were also tested by enzyme immunoassay (EIA) to quantify antigenicity. Results: The agreement between Rapid TPAg and UBT in the evaluation of the results of H. pylori eradication treatment was 94.1%. The overall accuracy of Rapid TPAg and UBT to determine H. pylori eradication was 98.0 and 96.0%, respectively. The results of Rapid TPAg were not altered after storage of samples at −20 to 40°C for 7 days. Antigenicity quantified by EIA did not decrease significantly after 7 days. Conclusions: Rapid TPAg is a useful diagnostic test for immediate and accurate determination of the results of H. pylori eradication therapy. The antigenicity of stool sample suspensions was preserved for 7 days in the collection devices. [ABSTRACT FROM AUTHOR]

Background: Asthma considered as an inflammatory disease and the role of systemic and local oxidative stress in the pathogenesis of the disease has been suggested. The imbalance between oxidants and antioxidants has a significant role in the creation and control of asthma symptoms. The aim of this research was to study the relation between serum levels of oxidants and antioxidants with the severity of asthma. Methods: In this observational-analytic cross-sectional study, 59 known asthmatic patients were included. The severity of asthma as mild, moderate, and severe was determined in studied patients based on their medical history, clinical symptoms, and pulmonary function tests. Serum levels of hydrogen superoxide, specific activity of superoxide dismutase enzymes and catalase, and total capacity of antioxidant levels in serum samples were evaluated. Findings: Mild, moderate, and severe asthma was presented among 21 (35.6%), 22 (37.3%), and 16 (27.1%) patients. There was significant positive relationship between the severity of asthma and specific activity of superoxide dismutase (P = 0.04; r = 0.21), mean of serum superoxide hydrogen (P < 0.01; r = 0.23), and the total capacity of antioxidants (P < 0.01; r = 0.31). There was significant negative relationship between the severity of asthma and specific activity of plasma catalase (P = 0.01; r = 0.28). Conclusion: The findings of current study confirmed the role of oxidant/antioxidant balance in asthma severity. To determine the more precise mechanisms of these compounds on pulmonary disease, especially asthma, further interventional studies on the effect of balance modification of oxidant/antioxidant on the severity, control, and the molecular basis of the disease is needed. [ABSTRACT FROM AUTHOR]

Abstract: Fast determination of catalase-positive bacteria was easily performed by connecting a test strip to a self-made optical sensor and adding the reaction product, which was obtained from the hydrogen peroxide dismutation catalyzed by the bacterial catalase, to the reacting area of the test strip. The new type of the one-off test strip was designed and fabricated by immobilizing peroxidase and color-developing reagents on a supporting pad for the rapid determination of hydrogen peroxide. The signal of the optical sensor, which used a light-emitting diode as the monochromatic light resource, was based on the detection of the reflecting light from the reacting area on the test strip. The sensitivity, reproducibility and stability of the test strips were investigated and detection of catalase-positive bacteria in culture media and tofu samples was carried out respectively on the optical sensor. This technique allowed the quantification of Staphylococcus aureus (S. aureus), which was used as a model of the catalase-positive bacteria, with the detection limit of 2×102 cfumL−1 in culture media without bacteria enumeration. The assay time was 9.5min, including 8min for catalase-catalyzed reaction and 1.5min for the detection of remaining H2O2 on the sensor, respectively. Successive analysis was conveniently accomplished by replacing the one-off test strip. The proposed methodology is a rapid, straight-forward and cost-effective approach for the determination of catalase-positive bacteria in food samples. [Copyright &y& Elsevier]

Abstract: Semen manipulation and cryopreservation-thaw procedures may accelerate the generation of reactive oxygen species (ROS). Sperm exposure to large amounts of ROS has been shown to cause membrane lipid peroxidation and cellular injury to the sperm. The objective of this study was to overcome the ROS production in frozen-thawed ram semen by the addition of the antioxidants catalase or Trolox to semen following thawing. Frozen-thawed ram semen (100×106 sperm/straw) was supplemented with PBS (control group), 100μg/ml catalase, or 100μMTrolox/108 sperm (catalase and Trolox being dissolved in PBS) and incubated (37°C) for 5min. Under the experimental conditions used in this study, the catalase and Trolox antioxidants failed to protect the sperm from the spontaneous production of ROS. However, when lipid peroxidation was induced by iron (FeSO4), the addition of Trolox promoted a reduction (P <0.05) in the formation of TBARS in the semen, compared to the control and catalase semen samples. The generation of TBARS and H2O2 occurred in the extender alone, without the presence of sperm cells. In conclusion, the addition of Trolox to frozen-thawed ram semen could be beneficial as it decreases the production of TBARS when oxidative stress is induced. It is possible that a longer incubation period could lead to different results. The concentration of catalase also needs to be further evaluated. The extender could contribute to the oxidative stress of sperm, as it is a source of ROS during the cryopreservation of semen. [Copyright &y& Elsevier]

Abstract: The antioxidant properties of different extracts of Halenia elliptica was investigated by employing various established in vitro systems. The results showed that various extracts possessed strong antioxidant activity in vitro, and the 70% methanol extract (ME) had the strongest antioxidant activity. Based on our in vitro results, ME was used for investigating the antioxidant properties of H. elliptica in vivo. The liver and kidney of CCl4-intoxicated animals exhibited a significant decrease in superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) levels. Additionally, these organs exhibited a significant increase in the level of malondialdehyde (MDA). These changes were significantly reversed, in a dose-dependent manner, after treatment with ME and the standard treatment Vitamin E. Thus, it may be concluded that the ME possesses potent antioxidant properties, and might be valuable natural source of antioxidants that could be applicable to both the medical and food industries. [Copyright &y& Elsevier]

Objectives: Staphylococci were most prominent factors that responsible for skin, soft tissue and foreign body infections. Gaining resistance to methicillin and various antibiotics in these microorganisms over the years increased morbidity and mortality, especially in hospitalized patients. In such situations number of preferred antibiotics was limited. The aim of this study was to investigate in-vitro susceptibility of fusidic acid to clinic isolates of Staphylococci. Materials and methods: The seventy-seven coagulase negative staphylococci (CNS) and 37 Staphylococcus aureus strains isolated from various clinical specimens were included in this study. Staphylococci were identified with gram stain, catalase and coagulase tests. According to "Clinical and Laboratory Standards Institute (CLSI)" criteria, antimicrobial susceptibility testing was performed by Kirby-Bauer disc diffusion method. Results: The seventy-four percent of the isolated CNS were defined as methicillin sensitive-CNS (MS-CNS), 26% of the isolated CNS were defined as methicillin resistant (MR-CNS). While 40% of MR-CNS was resistant to fusidic acid, fusidic acid resistance was found to be 24% in MS-CNS. In methicilline-sensitive S.aureus strains fusidic acid resistance rate were detected as 13%; and in methicillin-resistant S.aureus strains the rate were 14%. Conclusion: Susceptibility of fusidic acid in Staphylococcus aureus strains were found higher than coagulase-negative staphylococci. Fusidic acid remains as an alternative in the treatment of infections due to staphylococci. [ABSTRACT FROM AUTHOR]

Abstract: We have investigated the fate of Staphylococcus aureus by starving the cells and maintaining them in natural seawater at 22 and 4°C. At 22°C, cells developed a long-term survival state where about 0.037% of the initial population remained culturable over more than 7months, whereas at 4°C, bacteria lost culturability and transiently entered into the viable but non-culturable state (VBNC). However, after 22days of entry into the VBNC state, the number of viable cells detected via the direct viable count method decreased significantly. We show here that mutational inactivation of catalase (KatA) or superoxide dismutase (SodA) rendered strains hypersensitive to seawater stress at 4°C and consequently, part of the seawater lethality on S. aureus at low temperature is mediated by reactive oxygen species (ROS) during microcosm-survival process. Shifting the temperature from 4 to 22°C of totally non-culturable wild-type cells induced a partial recovery of the population. However, deficiencies in catalase or superoxide dismutase prevent resuscitation ability. [ABSTRACT FROM AUTHOR]

Bacteremia occurs frequently in newborn calves. The predictive value of clinical signs is low, suggesting the use of calf-side diagnostic tests. To investigate testing of urine catalase activity (Uriscreen test) for bacteriuria and bacteremia detection. Five colostrum-free calves and 3 colostrum-fed control calves. Controlled experimental trial. Colostrum-free calves were inoculated PO with Escherichia coli O78+. A clinical score was established to define the onset of the illness. Blood and urine (cystocentesis) samplings and cultures, and Uriscreen tests, were performed 4-6 times from inoculation to death. Three control calves received the same management as 3 inoculated calves, but with colostrum and without inoculation. Bacteremia was demonstrated in all of the inoculated colostrum-free calves and in none of the control calves. The E. coli O78+ strain, E. coli, and Klebsiella spp. were recovered from 4/5, 5/5, and 2/5 inoculated colostrum-free calves, respectively. Urine cultures were negative for the 2 groups at the start of the experiment; 5/5 colostrum-deprived inoculated calves were positive for E. coli thereafter whereas 3/3 controls remained negative. Concordance of Uriscreen tests with bacteremia and bacteriuria was 0.86 and 0.88, respectively. Kappa value of agreement between Uriscreen and bacteremia and bacteriuria was 0.73 and 0.76, respectively. Sensitivity of Uriscreen for bacteremia and bacteriuria was 80.0 and 86.6%, respectively, and specificity was 92.8 and 88.8%, respectively. The results suggest that Uriscreen can be used for detection of bacteremia in neonatal calves in connection with a constant bacteriuria. [ABSTRACT FROM AUTHOR]

In many areas of the world, polybrominated diphenyl ethers are ubiquitous due to their use as fire retardants. It is known that the hydrophobic characteristics of PBDEs cause them to sink in soil and sediment, yet their effect on microbes within the soil is not well understood. In this study, soil was treated with 1, 10, and 100 mg kg BDE 209 for up to 45 days. Treatment effects on soil enzymatic activities for urease and catalase were evaluated. The impact on the microbe community structure was estimated using denaturing gradient gel electrophoresis after polymerase chain reaction amplification of total genomic DNA, using bacterial variable V3 region targeted primers. The effects on the soil microbial community size and major bacterial groups were evaluated using fluorescence in situ hybridization analysis. Forty-five days after the addition of BDE 209, urease activity was suppressed by BDE 209, even at a concentration of 1 mg kg. Catalase activity increased in the samples containing lower concentrations of BDE 209, but was suppressed in samples containing higher concentrations. The bacterial community also varied in response to the addition of BDE 209, and the variation of community composition differed among treatments. In addition, α, β and γ subclass proteobacteria decreased in the group of 100 mg kg BDE 209 spiked soil after 45 days of treatment. Throughout the experiment, no BDE 209 degradation was detected under darkness. These observations demonstrated that BDE 209 in soil, although of low bioavailability, had an adverse impact on the structure and function of the soil microbial community and microbial processes. [ABSTRACT FROM AUTHOR]

Electron spin resonance (ESR) oximetry technique was applied for analysis of catalase activity in the present study. Catalase activity was evaluated by measuring oxygen from the reaction between hydrogen peroxide (H2O2) and catalase-positive cells. It was demonstrated that the ESR spectra of spin-label probes, 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPOL), 4-oxo-2,2,6,6-tetramethyl-1-piperidinyloxy (4-oxo-TEMPO) and 4-maleimido-2,2,6,6-tetramethyl-1-piperidinyloxy (4-maleimido-TEMPO) in the presence of H2O2 were broadened with the concentrations of catalase. It was possible to make a calibration curve for catalase activity by peak widths of the spectra of each spin-label probe, which are broadened dependently on catalase concentrations. The broadened ESR spectra were also observed when the catalase-positive micro-organisms or the mammalian cells originally from circulating monocytes/macrophages were mixed with TEMPOL and H2O2. Meanwhile, catalase-negative micro-organisms caused no broadening change of ESR spectra. The present study indicates that it is possible to evaluate directly the catalase activity of various micro-organisms and mammalian cells by using an ESR oximetry technique. [ABSTRACT FROM AUTHOR]

The enzyme catalase converts solar radiation into reactive oxidant species (ROS). In this study, we report that several bacterial catalases (hydroperoxidases, HP), including Escherichia coli HP-I and HP-II also generate reactive oxidants in response to ultraviolet B light (UVB). HP-I and HP-II are identical except for the presence of NADPH. We found that only one of the catalases, HPI, produces oxidants in response to UVB light, indicating a potential role for the nucleotide in ROS production. This prompts us to speculate that NADPH may act as a cofactor regulating ROS generation by mammalian catalases. Structural analysis of the NADPH domains of several mammalian catalases revealed that the nucleotide is bound in a constrained conformation and that UVB irradiation induces NADPH oxidation and positional changes. Biochemical and kinetic analysis indicate that ROS formation by the enzyme is enhanced by oxidation of the cofactor. Conformational changes following absorption of UVB light by catalase NADPH have the potential to facilitate ROS production by the enzyme. [ABSTRACT FROM AUTHOR]

Despite the importance of fish kidney in several functions (immune, metabolism and excretion of xenobiotics) its use in coastal water biomonitoring focusing on protection and damage is scarce. Five critical sites in Ria de Aveiro (Portugal; Barra-BAR, Gafanha-GAF, Rio Novo do Principe-RIO; Laranjo-LAR and Vagos- VAG) were assessed in comparison to a reference site (Torreira-TOR), focusing on Liza aurata kidney antioxidant defences versus damage responses. Non protein thiols were higher at RIO (near a former bleached kraft pulp mill effluent) and total glutathione at RIO, LAR (mercury contaminated) and VAG (polycyclic aromatic hydrocarbons contaminated). Catalase and glutathione S-transferase activities were higher at RIO and LAR whereas no differences were found in glutathione peroxidase activity. However, glutathione reductase was higher at BAR (subject to naval traffic), GAF (harbour water area), RIO and LAR. No peroxidative damage was observed despite the decreased DNA integrity at RIO and VAG. The integrated biomarker response index ranked impacted sites as: LAR>RIO>BAR>GAF>VAG>TOR. [ABSTRACT FROM AUTHOR]

Background: In the last 10 years, different studies have shown interesting geographical variations in the prevalence of different Malassezia species in pityriasis versicolor. Aim: Identification of Malassezia species isolated from patients with pityriasis versicolor. Methods: In 100 patients with pityriasis versicolor, Malassezia species were identified by culture in Sabouraud's dextrose agar containing cycloheximide with olive oil overlay and modified Dixon agar and by doing biochemical tests (catalase reaction, assimilation of glycine, and Tween utilisation tests). Results: In 10 patients, 10% KOH smear was negative, while in 90 patients the smear showed characteristic "spaghetti and meatball" appearance. Of these 90 cases, growth was obtained on modified Dixon's agar in 87 cases. Fifty of the isolates (57.5%) were M. globosa, 15 (17.2%) were M. sympodialis, seven (8.0%) were suspected M. sympodialis, 6 (6.9%) each of the isolates were M. furfur and M. obtusa, and three (3.4%) isolates were M. restricta. Conclusion: M. globosa was the most common species, followed by M. sympodialis, M. furfur, M. obtusa, and M. restricta. [ABSTRACT FROM AUTHOR]