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In this work, the antibacterial effect of fluoroquinolones (FQs) upon Escherichia coli (E.coli) was measured with and without application of 40kHz ultrasound (US) stimulation. The research results demonstrated that simultaneous application of 40kHz US apparently enhanced the antibacterial effectiveness of FQs. That is, the synergistic effect was observed and the bacterial viability was reduced when FQs and US were combined. In addition, various influencing factors, such as FQs drug concentration, US irradiation time and solution temperature, on the inhibition of E.coli were also investigated. The antibacterial activity was enhanced apparently with increasing of FQs drug concentration, US irradiation time and solution temperature. Furthermore, we discussed preliminarily the mechanism of US ...

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BackgroundBerberine is a plant alkaloid that is widely used as an anti-infective in traditional medicine. Escherichia coli exposed to berberine form filaments, suggesting...Full Text Available

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Many organic compounds can be adsorbed onto the interface of a metal and solution to form a thin film that inhibits the corrosion process according to a blocking and/or negative catalytic effect. Using the Langmuir-Blodgett (LB) technique, stearic acid (SA) monolayers were deposited onto the surface of an iron (Fe) electrode to study the inhibition effect and the mechanism of SA in a neutral medium. Molecular orientation and the number of deposited monolayers of SA were shown to have marked effects on inhibition of Fe corrosion. The inhibition mechanism depended mainly on blocking.

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Mechanism-based inhibition of cytochrome P450 (CYP) 3A4 is characterized by NADPH-, time-, and concentration-dependent enzyme inactivation, occurring when some drugs are converted by CYPs to reactive...Full Text Available

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Insect host/parasitoid interactions are co-evolved systems in which host defenses are balanced by parasitoid mechanisms to disable or hide from host immune effectors. Although there is a rich literature on these systems, parasitoid immune-disabling mechanisms have not been fully elucidated. Here we report on a newly discovered immune-disabling mechanism in the Pieris rapae/Pteromalus puparum host/parasitoid system. Because venom injections and parasitization suppresses host phagocytosis, we turned attention to the P. rapae scavenger receptor (Pr-SR), posing the hypothesis that P. puparum venom suppresses expression of the host Pr-SR gene. To test our hypothesis, we cloned a full-length cDNA of the Pr-SR. Multiple sequences alignment showed the deduced amino acid sequence of Pr-SR is similar to scavenger receptors of other lepidopterans. Bacterial and bead injections induced Pr-SR mRNA and protein ...

International Nuclear Information System (INIS)

The analgesic, dipyrone (1,phenyl-2,3-dimethyl-5-pyrazolone-4-methylamino methane sulphonate sodium), at 20 mM concentration, inhibited the rejoining of single-strand scissions in DNA of Escherichia coli B/r cells induced by 20 krad gamma-radiation. The chemical altered the cell membrane structure as evidenced from the uptake of acriflavin, the efflux of potassium ions from the bacterial cells and the inhibition of alkaline phosphatase-a cell membrane associated enzyme. (author).

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In regions of high bone loading, the mechanoresponsive osteocytes inhibit osteoclastic bone resorption by producing signaling molecules. One possible candidate is matrix extracellular phosphoglycoprotein...Full Text Available

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Zinc is an essential trace metal ion for growth, but an excess of Zn is toxic and microorganisms express diverse resistance mechanisms. To understand global bacterial responses to excess Zn, we conducted...Full Text Available

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A dialyzable factor(s) in human serum is known to stimulate gonococcal oxygen consumption. Its effect on other human pathogens was investigated. A 10% serum solution increased peak O2 consumption for Escherichia coli and Staphylococcus aureus to 157% (P less than 0.05) and 199% (P less than 0.02), respectively, of their O2 consumption when suspended in Hanks balanced salt solution, compared with a 356% increase for Neisseria gonorrhoeae with serum. Dialyzed serum lacked stimulatory capacity. Bacteria, serum, and neutrophils are often incubated to evaluate neutrophil bactericidal activity. Samples of 10(8) N. gonorrhoeae, S. aureus, and E. coli turned resazurin colorless (anaerobic conditions, Eh less than -42 mV) after 7.4, 13.3, and 15.1 min, respectively. Because neutrophil formation of reactive oxygen intermediates requires ambient O2, the effect of live bacteria and serum on this process was explored. After 5 min of incubation of 10(8) N. gonorrhoeae or S. aureus in 10% normal or ...

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Indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO) are tryptophan-degrading enzymes. Mammalian IDO expression is induced by cytokines and has antimicrobial and immunomodulatory effects. A major role of mammalian TDO is to supply nicotinamide adenine dinucleotide (NAD(+)). In fungi, the IDO homologue is thought to be expressed constitutively and supply NAD(+), as TDO is absent from their genomes. Here, we reveal the distribution of IDO genes among fungal species and characterize their enzymatic activity. The yeast, Saccharomyces cerevisiae has only one IDO gene, whereas the koji-mold, Aspergillus oryzae has two genes, IDO? and IDO?. The A. oryzae IDO? showed more similar enzymatic properties to those of S. cerevisiae IDO than IDO?, suggesting that the A. oryzae IDO? is a functional homologue of the S. cerevisiae IDO. From the IDO? gene, two isoforms, IDO? and IDO?(+) could be generated by alternative splicing. The latter contained a 17 amino acids insertion which ...

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Clinical questionWhat is the best treatment for bacterial conjunctivitis?ResultsTopical antibiotics expedite recovery from bacterial conjunctivitis....Full Text Available

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NH₄⁺ inhibition kinetics for CH₄ oxidation were examined at near-atmospheric CH₄ concentrations in three upland forest soils. Whether NH₄⁺-independent...Full Text Available

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SummarySoluble epoxide hydrolase (sEH) is a key enzyme in the metabolic conversion and degradation of P450 eicosanoids called epoxyeicosatrienoic acids (EETs). Genetic variations...Full Text Available

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The cancer preventive action of (−)-epigallocatechin gallate (EGCG), found in green tea, is strongly supported by epidemiology and laboratory research data. However, the mechanism by...Full Text Available

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AIM: To analyze the antiviral mechanism of Epigallocatechin gallate (EGCG) against hepatitis B virus (HBV) replication.METHODS: In this research, the HBV-replicating cell line HepG2.117 was used...Full Text Available

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Psychopathic individuals are generally unresponsive to motivational and emotional cues that facilitate behavioral regulation. A putative mechanism for this deficiency is Gray’s (1971)...Full Text Available

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Lovatt et al. (1979 Plant Physiol 64: 562-569) have previously demonstrated that end-product inhibition functions as a mechanism regulating the activity of the orotic acid pathway in...Full Text Available

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We introduce a discrete multiplicative process as a generic model of competition. Players with different abilities successively join the game and compete for finite resources. Emergence of dominant players and evolutionary development occur as a phase transition. The competitive dynamics underlying this transition is understood from a formal analogy to statistical mechanics. The theory is applicable to bacterial competition, predicting novel population dynamics near criticality.

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In vivo effects of toxaphene on calcium pump activity in rat brain synaptosomes was studied. Male Sprague-Dawley rats were dosed with toxaphene at 0,25,50, and 100 mg/kg/day for 3 days and sacrificed 24 h after last dose. Ca/sup 2 +/-ATPase activity and /sup 45/Ca uptake were determined in brain P/sub 2/ fraction. Toxaphene inhibited both Ca/sup 2 +/-ATPase activity and /sup 45/Ca/sup 2 +/ uptake and the inhibition was dose dependent. Both substrate and Ca/sup 2 +/ activation kinetics of Ca/sup 2 +/-ATPase indicated non-competitive type of inhibition as evidenced by decreased catalytic velocity but not enzyme-substrate affinity. The inhibited Ca/sup 2 +/-ATPase activity and Ca/sup 2 +/ uptake were restored to normal level by exogenously added calmodulin which increased both velocity and affinity. The inhibition of Ca/sup 2 +/-ATPase activity and Ca/sup 2 +/ uptake and restoration by ...

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Abstract Silver-impregnated wound dressings continue to be routinely used for the management of infected wounds, or wounds that are at risk of becoming infected. The ability of antimicrobials that have been incorporated into wound dressings to kill microorganisms within the dressing requires appropriate evaluation using in vitro models. In vitro models that have been exploited for this purpose have included the corrected zone of inhibition and the log reduction assay. However, these and other related culturable-based assays are purported to have poor correlation with the overall microbicidal barrier activity of an antimicrobial wound dressing. This is because culturable-based methods only retrospectively indicate bacterial cell death and do not take into account viable but nonculturable st...

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Abstract Introduction.- Infection is the worst complication seen with inflatable penile prosthesis (IPP). Both the American Medical Systems (AMS) and Coloplast IPP have infection retardant coatings. AMS is coated at the factory with rifampicin and minocycline (InhibiZone). The Coloplast IPP has a hydrophilic coating covalently bonded to its components that will absorb any aqueous solution before implantation and provides increased surface lubricity to decrease bacterial adherence. Aim.- We tested several antibiotic dips comparing zones of inhibition (ZOI) against five commonly infecting bacteria with coated Coloplast implants. Results were compared with those ZOI created with strips of an AMS IPP precoated with InhibiZone. Methods.- Pieces of sterile Coloplast Titan IPP were dipped in (i) ...

International Nuclear Information System (INIS)

The inhibitor action of unbranched polyamines on corrosion of low-carbon steel in 0.5 M sulfuric acid is studied through potentiostatic polarization curves. It is shown that the inhibitor efficiency I depends on the polyamine concentration and molecular structure. The quantum-mechanical calculations of molecular properties are accomplished through the MNDO method. Correlation between the measured I and physicochemical properties of the polyamine inhibitors in protonized and nonprotonized form is found with application of the general perturbation theory

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Synergism has been observed during inhibiting initiated oxidation of styrene or tetralin by organic phosphites in the presence of complex compounds of some transition metals. The results are given of non-additive intensification of antioxidative activity of triphenylphosphite (TPP) and tri-(4-methyl-6-tert.-- butyl)-phenyl-phosphite (TMBP) in the process of initiated oxidation of styrene or tetralin with addition of acetylacetonates of cobalt and vanadyl. During styrene oxidation, inhibition of the reaction with chelate complex of vanadyl is weakened considerably when phosphite is added into the reaction system. During tetralin oxidation, postcatalytic (or branched) oxidation is observed only for large concentration of vanadyl complex. Addition of TPP to above complex sharply increases the induction period. When the induction period is completed, oxidation of tetralin follows the mechanism of usual, i.e. initiated, ...

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The initiation and inhibition of pitting corrosion on zirconium and hafnium in aqueous solutions have been investigated by potentiodynamic, potentiostatic and galvanostatic measurements at 25/sup 0/C. Effects of Cl/sup -/, Br/sup -/and I/sup -/ have been examined over a range of salt concentrations and pH. All three halide ions cause pitting attack on the two metals, but this may be inhibited by other anions. The results show that hafnium is more easily protected against pitting than is zirconium. The data are treated by the Butler-Volmer equation to yield more information about the mechanisms of the pitting corrosion.

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The microbial safety of foods cooked in microwave ovens was investigated. The mechanisms of microwave destruction of microorganisms were examined. Effects of time and temperature on microorganisms in different food systems were described. Studies showed that: microwave heating of food is more ''''food dependent'' than conventional heating; recommended microwave treatment time for some foods may not destroy high levels of bacteria; use of microwaves in combination with conventional heating methods results in more uniform heating of foods and destruction of bacteria; and microwaves exert different killing effects on individual bacterial species. (78 references, 2 tables)

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PP2B is a Ca2+/calmodulin-dependent protein phosphatase that is ubiquitously expressed in mammals. Among other actions, it is an effector mechanism in NMDA-mediated glutamate neurotransmission as well as a regulator of GSK3? and MAPK signaling cascades. Because all of these mechanisms have demonstrable roles in the control of circadian rhythyms, we hypothesized that PP2B would be a key regulator of rhythm generation and entrainment, and that through inhibition of its phosphatase activity, the circadian system would be affected by immunosuppressant drug therapy. We report here that immunosuppressant drugs (cyclosporin A, FK506) (1) block the circadian responses to light that underlie photic entrainment; (2) produce circadian phase shifts with a characteristic nonphotic profile; and (3) disr...

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Experiments were performed to investigate the involvement of the cell membrane in the excision DNA repair process in Escherichia coli. Two membrane-binding drugs, procaine and phenethyl alcohol (PEA), inhibited liquid-holding recovery (LBR) in u.v.-irradiated E. coli wild-type and recA strains. In uvrB and polA strains where, after u.v.-irradiation, LHR was absent the two drugs had no effect. Both drugs markedly reduced the removal of u.v.-induced thymine dimers in the DNA of wild-type cells (H/r30). Analysis by alkaline sucrose gradients revealed that PEA inhibited the incision step in excision repair. In contrast, procaine had no effect on incision but apparently inhibited the late steps in excision repair. PEA dissociated DNA from the cell membrane, whereas procaine did not. The results suggest that the two drugs PEA and procaine inhibit LHR and the excision repair process operating on u.v.-induced ...

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The acid corrosion inhibition process of mild steel in 1 M HCl by 1-butyl-3-methylimidazolium chlorides (BMIC) and 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM]HSO_4) has been investigated using electrochemical impedance, potentiodynamic polarization and weight loss measurements. Potentiodynamic polarization studies indicate the studied inhibitors are mixed type inhibitors. For both inhibitors, the inhibition efficiency increased with increase in the concentration of the inhibitor and the effectiveness of the two inhibitors are in the order [BMIM]HSO_4 > BMIC. The adsorption of the inhibitors on mild steel surface obeyed the Langmuir's adsorption isotherm. The effect of temperature on the corrosion behavior in the presence of 5 x 10"-"3 M of inhibitors was studied in the temperature range of 303-333 K. The associated activation energy of corrosion and other thermodynamic parameters such as enthalpy of activation (#DELTA#H), entropy of ...

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Spice extracts under the form of essential oils were tested for their efficiency to increase the relative radiosensitivity of Listeria monocytogenes and Escherichia coli O157H7 in culture media. The two pathogens were treated by gamma-irradiation alone or in combination with oregano essential oil to evaluate their mechanism of action. The membrane murein composition, and the intracellular and extracellular concentration of ATP was determined. The bacterial strains were treated with two irradiation doses: 1.2 kGy to induce cell damage and 3.5 kGy to cause cell death for L. monocytogenes. A dose of 0.4 kGy to induce cell damages, 1.1 kGy to obtain viable but nonculturable (VBNC) state and 1.3 kGy to obtain a lethal dose was also applied on E. coli O157H7. Oregano essential oil was used at 0.020% and 0.025% (w/v), which is the minimum inhibitory concentration (MIC) for L. monocytogenes. For E. coli O157H7, a concentration of 0.006% and 0.025% ...

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The present study was undertaken to determine the involvement of calcium-protein kinase C pathway in the mechanism of action of Escherichia coli heat stable enterotoxin (STa) apart from STa-induced activation of guanylate cyclase in human colonic carcinoma cell line COLO-205, which was used as a model cultured cell line to study the mechanism of action of E. coli STa. In response to E. coli STa, protein kinase C (PKC) activity was increased in a time-dependent manner with its physical translocation from cytosol to membrane. Inhibition of the PKC activity in membrane fraction and inhibition of its physical translocation in response to IP_3-mediated calcium release inhibitor dantrolene suggested the involvement of intracellular store depletion in the regulation of PKC activity. Among different PKC isoforms, predominant involvement of calcium-dependent protein kinase C (PKC#alpha#) was specified using ...

UK PubMed Central (United Kingdom)

IntroductionThe major risk factor for osteoarthritis (OA) is aging, but the mechanisms underlying this risk are only partly understood. Age-related accumulation of advanced glycation...Full Text Available

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In the past decade, the large tailings pond (Mildred Lake Settling Basin) on the Syncrude Canada Ltd. lease near Fort McMurray, Alta., has gone methanogenic. Currently, about 60%-80% of the flux of gas across the surface of the tailings pond is methane. As well as adding to greenhouse gas emissions, the production of methane in the fine tailings zone of this and other settling basins may affect the performance of these settling basins and impact reclamation options. Enumeration studies found methanogens (10(5)-10(6) MPN/g) within the fine tailings zone of various oil sands waste settling basins. SRB were also present (10(4)-10(5) MPN/g) with elevated numbers when sulfate was available. The methanogenic population was robust, and sample storage up to 9 months at 4 degrees C did not cause the MPN values to change. Nor was the ability of the consortium to produce methane delayed or less efficient after storage. Under laboratory conditions, fine tailings samples released 0.10-0.25 mL CH4 ...

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The bacterial strain E1R-j, isolated as an endophyte from wheat roots, exhibited high antifungal activity to Gaeumannomyces graminis var. tritici (Ggt). Strain E1R-j was identified as Bacillus subtilis based on morphological, physiological and biochemical methods as well as on 16S rDNA analysis. This strain inhibited mycelium growth in vitro of numerous plant pathogenic fungi, especially of Ggt, Coniothyrium diplodiella, Phomopsis sp. and Sclerotinia sclerotiorum. In greenhouse experiments, soil drenches with cell densities of 106, 109 and 1012CFU ml-1 E1R-j reduced significantly take-all disease, caused by Ggt, in wheat seedling by 62.6%, 68.6% and 70.7%, respectively, compared to the inoculated control, 4weeks after sowing. Growth parameters such as lengths and fresh weights of roots and...

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Spike-timing-dependent plasticity (STDP), a form of Hebbian plasticity, is inherently stabilizing. Whether and how GABAergic inhibition influences STDP is not well understood. Using a model neuron driven by converging inputs modifiable by STDP, we determined that a sufficient level of inhibition was critical to ensure that temporal coherence (correlation among presynaptic spike times) of synaptic inputs, rather than initial strength or number of inputs within a pathway, controlled postsynaptic spike timing. Inhibition exerted this effect by preferentially reducing synaptic efficacy, the ability of inputs to evoke postsynaptic action potentials, of the less coherent inputs. In visual cortical slices, inhibition potently reduced synaptic efficacy at ages during but not before the critical period of ocular dominance (OD) plasticity. Whole-cell recordings revealed that the amplitude of unitary IPSCs from ...

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Chemoreceptors are crucial components in the bacterial sensory systems that mediate chemotaxis. Chemotactic responses exhibit exquisite sensitivity, extensive dynamic range and precise adaptation....Full Text Available

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Self-assembled monolayer (SAM) of histidine (His) was prepared on copper surface at various pH values. The effect of KI additives on corrosion protection efficiency of His SAM was also studied. The protection abilities of these films against copper corrosion in 0.5 M HCl aqueous solution were investigated using electrochemical impedance spectroscopy and polarization techniques. The results show that the film formed on the electrode is more stable at pH = 10 than that at other pH values. When the iodide ions were added into the His self-assembly solution (pH = 10), protection efficiency was further improved. The inhibition mechanism has been discussed by quantum chemical calculations.

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The effect of sodium gluconate anion (SG) on the corrosion and scale inhibition of ordinary steel in simulated cooling water has been studied using weight loss, polarisation curves, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) techniques. SG was studied in concentration from 10{sup -4} M to 10{sup -1} M. Results obtained reveal that SG perform excellently as corrosion and scaling inhibitor for ordinary steel in simulated cooling water. An increase of SG concentration leads to the increase of the corrosion potential towards the positive direction. The inhibition efficiency was a low temperature dependence. The inhibitor mechanism was treated as an adsorption process according to Langmuir adsorption isotherm. The SEM/EDAX data show that was a corrosion and scale inhibitor.

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In this study, we investigated the kinetics of linoleic acid production via lipase-mediated hydrolysis of corn DDGS oil in a batch reactor with continuous mechanical agitation and developed a kinetic model that incorporated the product inhibition to study the complete hydrolysis. The model agreed very well with observed data; though situations with low enzyme dosage or low stirring rates were modeled successfully without product inhibition, actual product concentration in such situations was too low to exert any inhibitory effects. Increasing the enzyme concentration increased hydrolysis, and beyond certain enzyme concentrations, effects tended to fade away because of excessive enzyme desorption from the interface. An enzyme dosage within the range of 40-60KLU/L of oil dispersion could be ...

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Abstract. The potential effects of synthetic unmethylated oligodeoxynucleotides (ODN) containing CpG motifs, mimicking bacterial DNA, has never been evaluated on the immune response in the teleost fish gilthead seabream (Sparus aurata), the most important fish species in Mediterranean aquaculture. First, binding and competition studies have demonstrated that binding is saturated and promiscuous, suggesting the participation of several receptors. Moreover, leucocyte cytotoxic (NCC) activity, production of ROIs (reactive oxygen intermediates), and expression of immune-relevant genes was greatly primed by ODNs. Focusing on the mechanism, the TLR9 gene is widely distributed in seabream tissues and differently regulated in vitro by several stimuli. Moreover, and for the first time in fish, TLR9...

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Abstract Alkali tolerance and the mechanism of microcystin (MC) degradation were investigated in the MC-degrading bacterial species, Sphingopyxis sp. C-1, to better understand the increased MC degradation under the alkaline conditions that arise during the disappearance of water blooms. MC-degrading bacteria harbour mlrA, mlrB and mlrC that encode MC-degrading enzymes. Sphingopyxis sp. C-1 also possesses these genes, as well as the mlrD gene that has been assumed to encode MC and its degradation transporter. This study demonstrated that MC degradation activity was promoted by the intermittent addition of microcystin-LR (MCLR) to cultures of strain C-1. That the expression of mlrA, mlrB and mlrC is induced by MCLR also was indicated, whereas that of mlrA and mlrB is induced by the MCLR degr...

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Ethnopharmacological relevance: Extracts of the roots of Scutellaria baicalensis Georgi (Labiatae) have been widely used to relieve fever related to bacterial infection and inflammatory diseases in traditional Korean medicine and have been reported to be effective in brain diseases. These experiments were conducted to examine the effects of oral administration of Scutellaria baicalensis extracts on the rescue of memory impairments induced by chronic cerebral hypoperfusion or chronic lipopolysaccharide (LPS) infusion. In addition, the underlying mechanisms of these effects were investigated. Materials and methods: In the first experiment, chronic cerebral hypoperfusion was induced in male Wister rats by bilateral common carotid artery occlusion (BCCAo). Daily administration of Scutellaria b...

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Morusin is a pure compound isolated from root bark of Morusaustralis (Moraceae). In this study, we demonstrated that morusin significantly inhibited the growth and clonogenicity of human colorectal cancer HT-29 cells. Apoptosis induced by morusin was characterized by accumulation of cells at the sub-G_1 phase, fragmentation of DNA, and condensation of chromatin. Morusin also inhibited the phosphorylation of IKK-#alpha#, IKK-#beta# and I#kappa#B-#alpha#, increased expression of I#kappa#B-#alpha#, and suppressed nuclear translocation of NF-#kappa#B and its DNA binding activity. Dephosphorylation of NF-#kappa#B upstream regulators PI3K, Akt and PDK1 was also displayed. In addition, activation of caspase-8, change of mitochondrial membrane potential, release of cytochrome c and Smac/DIABLO, and activation of caspase-9 and -3 were observed at the early time point. Downregulation in the expression of Ku70 and XIAP was exhibited afterward. Caspase-8 ...

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The objective of this work was to investigate the efficiency of imidazole and its derivatives 4-methylimidazone, 4-methyl-5-hydroxymethylimidazone, 1-phenyl-4-methylimidazone, and 1-(p-tolyl)-4-methylimidazole for corrosion inhibition of copper in 0.5 M hydrochloric acid. Corrosion inhibition was studied using potentiodynamic methods. These studies have shown that 1-(p-tolyl)-4-methylimidazole has the best inhibitory efficiency. Activation energies were obtained by measuring the temperature dependence of the corrosion current. The activation energies in the presence of the various inhibitors are low (3--5 kJ/mol), with the best inhibitor showing the highest value. The adsorptive behavior of the imidazole derivatives on the copper electrode surface follows a Freundlich-type isotherm. The standard free energies of adsorption are also low (14--16 kJ/mol), indicating that imidazole and its derivatives physisorb on the copper surface. Possible ...

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PMID:12439520

KoreaScience (Korea)

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The objectives of the project were to develop operational techniques for promoting contaminant hideout return from tube support crevices and to identify the effect of chemical inhibitor application on corrodent transport. The implementation of routine procedures for promoting the return of sequestered corrodents could retard the progression of denting or other corrosion processes and improve steam generator availability. Tests also quantified the effect of inhibitor application on crevice hideout and hideout return processes, with the intention of developing a better understanding of the inhibition mechanism. By carefully monitoring the hideout and hideout return inventories, the program also has provided the opportunity to study steam generator concentration processes in general.

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The influence of selenium dioxide (SeO2) on the microstructure and electrodeposition of manganese coatings obtained from a sulfate based neutral solution was investigated by material characterization methods and electrochemical techniques. The crystal structure and surface morphology of these coatings were studied by scanning electron microscopy (SEM) and powder X-ray diffraction spectroscopy (XRD), respectively. The SEM and XRD data showed that SeO2 could effectively accelerate phase transformation, and facilitate leveled and fine grain growth. The electrochemical results indicated that SeO2 could inhibit hydrogen evolution reaction and promote manganese deposition. The action of selenium dioxide in manganese deposition was found to be a reduction and adsorption mechanism. The process cou...

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Two physical pre-treatment methods, particle size reduction by grinding and thermo-mechanical extrusion, were evaluated as alternatives to traditional biomass pretreatments for lignocellulosic ethanol. Commonly available agricultural co-products wheat bran and soybean hull were the model substrates. Extrusion led to higher reducing sugar yields as compared to grinding for wheat bran, but not in the case of soybean hulls. The best combination of extrusion screw speed and maximum barrel temperature were 7 Hz/150 ?C and 3.7 Hz/110 ?C. The use of a solvent mixture (sodium hydroxide, urea, and thiourea) and calcium chloride solution in combination with extrusion treatment did not lead to improvement in reducing sugar yield. However, extensive washing to get rid of solvents and enzymatic inhibit...

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Liver paste or foie gras, which is a French term meaning fatty liver, was produced traditionally from goose and duck. Chickens are also used in the making of foie gras. The present study deals with the properties and quality of raw chicken and duck liver in comparison with manufactured liver paste (foie gras). Raw chicken liver contained 24.60% protein, 6.00% fat, 1.40 % ash, and 66.80% moisture. The average mineral values were 83.65, 50.75, 5.29, 1.15, 0.154, 0.683, 0.317 and 0.066 {mu}g/g of Fe, Zn, Cu, Mn, Cd, Pb, Ni, and Cr, respectively. The processing of liver paste (Foie gras) changed the composition of raw liver due to a loss in moisture, a release of fat and the addition of butter as a fat source. Chicken liver paste contained 27.8% moisture, 10.1% protein, 58.2% fat, and 0.8% ash. Mineral contents were 68.90, 40.50, 1.60, 1.1, 0.08, 0.22, 0.04 and 0.04 {mu}g/g of Fe, Zn, Cu, Mn, Cd, Pb, Ni, and Cr, respectively. The chemical, microbiological and sensory evaluation of liver ...

UK PubMed Central (United Kingdom)

Norepinephrine stimulates the growth of a range of bacterial species in nutritionally poor SAPI minimal salts medium containing 30% serum. Addition of size-fractionated serum components to SAPI...Full Text Available

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Fatty acid biomarker analysis coupled with gas chromatography-isotope ratio mass spectrometry was used to confirm the presence of methanotrophic and thiotrophic bacterial endosymbionts in the tissues...Full Text Available

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The results of antibiotic tests on bacterial pathogens freshly isolated from avian tissues and bovine milk are presented. Coliform isolates from the avian species showed an increased resistance to...Full Text Available

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The objective of this study was to determine if inflammatory tolerance and enhancement of innate immune function could be induced by the gram-positive cell wall component peptidoglycan (PGN)....Full Text Available

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Severe pericardial effusion is a rare complication of bacterial pneumonia and it usually disappears under medical treatment. Herein we report a case of a girl with a congenital immunodeficient syndrome...Full Text Available

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Neonatal bacterial infection in rats alters the responses to a variety of subsequent challenges later in life. Here we explored the effects of neonatal bacterial infection on a subsequent drug...Full Text Available

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The vaginal bacterial microbiota of 19 premenopausal women was examined by PCR-denaturing gradient gel electrophoresis (DGGE) and sequencing of the V2-V3 region of the 16S rRNA gene. Ten of the women...Full Text Available

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The genetic systems of bacteria that have the ability to use organic pollutants as carbon and energy sources can be adapted to create bacterial biosensors for the detection of industrial pollution....Full Text Available

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Aim:The effect of Tualang honey on wound healing in bacterial contaminated full-thickness burn wounds was evaluated in 36 male Sprague Dawley rats.Materials...Full Text Available

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BackgroundBacterial vaginosis (BV) is a common condition that is associated with preterm birth and acquisition of complex communities of vaginal bacteria that include several fastidious...Full Text Available

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Bacterial pathogens use virulence strategies to invade epithelial barriers, but active processes of epithelial cells may also contribute to the endocytosis of microbial particles. To focus on the latter,...Full Text Available

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We have used a sintered glass bead core to simulate the spaces and surfaces of reservoir rock in studies of the bacterial plugging phenomenon that affects waterflood oil recovery operations. The passage...Full Text Available

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Gene expression from bacterial artificial chromosome (BAC) clones has been demonstrated to facilitate physiologically relevant levels compared to viral and nonviral cDNA vectors. BACs are large enough...Full Text Available

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Model systems to study the effects of chemicals of environmental concern on bacterial and parasitic diseases as well as the immunosurveillance and destruction of transplantable tumor cells were described...Full Text Available

UK PubMed Central (United Kingdom)

Little is known about the conservation of determinants for the identities of tRNAs between organisms. We showed previously that Escherichia coli tyrosine tRNA synthetase can charge the Saccharomyces...Full Text Available

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Weight loss measurements were performed in 20% and 28% hydrochloric acid at 90/sup 0/C on carbon steel, 22Cr5Ni duplex stainless steel, and two superaustenitic steels - 27Cr31Ni3Mo and 19Cr25Ni4Mo -, in presence of organic substances used singly or mixed. The organic substances examined were quaternary ammonium salts (1-4-pyridyl)-pyridinium chloride hydrochloride, dodecylpyridiniumchloride, benzyldimethylstearylammonium chloride, and dodecyltrimethylammonium bromide), alkynols (1-octyn-3-ol, propargyl alcohol) and trans-cinnamaldehyde. The synergistic effect of potassium iodide on the inhibitive efficiency of the organic substances was studied. The variations of corrosion rate during the test time (normally six hours) were recorded by means of polarization resistance measurements. Polarization curves were also recorded. The results showed that the corrosion rates of the four steels examined can be reduced to less than 1 mg/cm/sup -2/ . h/sup -1/ using ternary ...

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An analysis was made on corrosion suppression mechanism of glycoletherdiaminetetraacetic acid (GEDTA) film made from GEDTA on stainless steel, and its corrosion inhibition effect. Results of analysis using IR spectrum, IR-ATR spectrum, {sup 1} HNMR spectrum, and ESCA spectrum indicated the deposition of the GEDTA film is a chemical deposition. In polarization tests at pH = 5 and 7, both polarization curves shifted to the constant current density side, showing suppression effect in reactions at both pH. When the corrosion environment is made severer, such as to pH = 2 and 4, the corrosion suppression effect of GEDTA became more distinctive. A ferroxyl test identified very little difference between untreated and treated materials. In a chemical pitting test, because oxidant and corrosive anion coexist in the test solution, and GEDTA is stable against corrosive anion Cl {sup {minus}}, the film is unstable against the oxidant. 39 refs., 12 figs., 6 ...

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Samples of ultra-high molecular weight polyethylene (UHMWPE) and nylon 66, of grades suitable for use in medical prostheses, were subjected to irradiation using a /sup 60/Co source. The effects of a 10 Mrad dose on percentage crystallinity, tensile behaviour and dynamic mechanical response were established 3 days after irradiation at intervals over a one year period. Crystallinity in UHMWPE was found to increase progressively during this period with consequent changes in mechanical behaviour. It is proposed that the observed ageing process arises from the breakdown of metastable groups in the polymer, which are formed on irradiation, with consequent release of long inter-lamella tie chains. This removes an inhibition to crystal perfection processes, which can occur at room temperature in polyethylene. Infra-red spectroscopic evidence supports the proposal that the metastable species is peroxy or hydroperoxy and that this ...

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Photosynthetic carbohydrates from the leaves are exported through the phloem to growing tips, roots, flowers and fruits. If sucrose labelled with {sup 14}C is applied to the leaves of bean plants, the pathway for sugar movement may be readily observed by autoradiography. Students apply the labelled sucrose during class time and return the next day to press their plants. During the next class, the pressed and dried plants are placed against X-ray film and left in the dark for four weeks. the film is then developed, examined for presence of label and compared to the pressed plants. Source to sink movement is clearly illustrated and information about the mechanism of phloem transport and loading is gained through experimental treatments, which include blocking the phloem pathway and inhibiting energy production.

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In previous studies we have demonstrated that prion protein (PrP) interacts with tubulin and disrupts microtubular cytoskeleton by inducing tubulin oligomerization. These observations may explain the molecular mechanism of toxicity of cytoplasmic PrP in transmissible spongiform encephalopathies (TSEs). Here, we check whether microtubule associated proteins (MAPs) that regulate microtubule stability, influence the PrP-induced oligomerization of tubulin. We show that tubulin preparations depleted of MAPs are more prone to oligomerization by PrP than those containing traces of MAPs. Tau protein, a major neuronal member of the MAPs family, reduces the effect of PrP. Importantly, phosphorylation of Tau abolishes its ability to affect the PrP-induced oligomerization of tubulin. We propose that t...

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Various chemical, physical, and mechanical methods to prevent unwanted deposition of mineral scale are described. The suitability of the different methods, which largely depends on the specific features and requirements of the system involved, is discussed. Special emphasis is placed upon the threshold treatment, where the growth process is retarded by the addition of trace amounts of growth inhibitors. Growth experiments have been performed on barium sulfate and calcium sulfate dihydrate seed crystals, suspended in a supersaturated solution with and without organic bisphosphonates as inhibitors. Two methods are selected for the analysis of the growth data. A degree of inhibition is defined to obtain a quantitative description of the influence of a growth inhibitor on the growth rate of the crystals. In addition the influence of the molecular structure of various bisphosphonates with different substituents is shown. The effect of a ...

British Library Electronic Table of Contents (United Kingdom)

Cancer cells recruit monocytes, macrophages and other inflammatory cells by producing abundant chemoattractants and growth factors, such as macrophage colony-stimulating factor (M-CSF/CSF-1) and monocyte chemoattractant protein-1 (MCP-1/CCL2), to promote tumor growth and dissemination. An understanding of the mechanisms that target cancer cells and regulate tumor microenvironment is essential in designing anticancer therapies. Here, we showed that serum amyloid-A (SAA) and cathelicidin (LL-37) stimulated M-CSF and MCP-1 expression with or without lipopolysaccharide (LPS) administration; conversely, lipoxin-A4 (LXA4) and annexin-A1 (ANXA1) inhibited LPS-induced M-CSF and MCP-1 production by human (HepG2) and mouse (H22) hepatocellular carcinoma cells (HCCs). The effects of LXA4, ANXA1, SAA ...

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Red mud suspensions are studied as passivating agents for iron in alkaline chloride media. Red mud particles in alkaline media are negatively charged, and can absorb considerable amounts of protons without significant changes in pH. These particles adhere easily to an iron surface forming aggregates of heterogeneous shape, smaller than 10 {mu}mx10 {mu}m. These adhered particles recrystallise on potential cycling, and hinder metal dissolution and magnetite formation. Carbon steel samples passivated in red mud suspensions become resistant to corrosion in alkaline chloride media. Corrosion potential versus time records and impedance spectroscopy measurements allow formulating some hypotheses about the inhibiting mechanism.

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Abstract The heterotetrameric K++-channel KCNQ1/KCNE1 is expressed in heart, skeletal muscle, liver and several epithelia including the renal proximal tubule. In the heart, it contributes to the repolarization of cardiomyocytes. The repolarization is impaired in ischemia. Ischemia stimulates the AMP-activated protein kinase (AMPK), a serine/threonine kinase, sensing energy depletion and stimulating several cellular mechanisms to enhance energy production and to limit energy utilization. AMPK has previously been shown to downregulate the epithelial Na++ channel ENaC, an effect mediated by the ubiquitin ligase Nedd4-2. The present study explored whether AMPK regulates KCNQ1/KCNE1. To this end, cRNA encoding KCNQ1/KCNE1 was injected into Xenopus oocytes with and without additional injection o...

British Library Electronic Table of Contents (United Kingdom)

Proton pump inhibitors are highly successful in treating gastroesophageal reflux disease, but a significant proportion of patients have persistent symptoms from weakly or nonacidic reflux. Transient lower esophageal sphincter relaxation (TLESR) represents the dominant mechanism of gastroesophageal reflux and has therefore become the most intensely investigated therapeutic target. The triggering of TLESR involve the vagal pathways and the ?-aminobutyric type B (GABA(B)) and metabotropic glutamate type 5 (mGluR5) receptors. Baclofen is a GABA(B) receptor agonist that is effective in inhibiting TLESR and reducing the number of reflux episodes, but is associated with significant central nervous system (CNS) side effects. The newer GABA(B) agonists, such as AZD9343 and AZD3355, and mGluR5 antag...

British Library Electronic Table of Contents (United Kingdom)

Glioblastoma multiforme is the most aggressive form of human brain tumor, which has no effective cure. Previously, we have demonstrated that overexpression of the C-terminal fragment of the human telomerase reverse transcriptase (hTERTC27) inhibits the growth and tumorigenicity of human cervical cancer HeLa cells. In this study, the therapeutic effect and molecular mechanisms of hTERTC27-mediated cancer gene therapy were further explored in vivo in established human glioblastoma xenografts in nude mice. We showed that intratumoral injection of adeno-associated virus carrying hTERTC27 (rAAV-hTERTC27) is highly effective in reducing the growth of the subcutaneously transplanted glioblastoma tumors. Histological analyses showed that rAAV-hTERTC27 treatment leads to profound necrosis, apoptosi...

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The hypothesis that intracellular Ca/sup 2 +/ is an essential component of the intracellular mechanism of insulin action in the adipocyte was evaluated. Cells were loaded with the Ca/sup 2 +/ chelator quin-2, by preincubating them with quin-2 AM, the tetrakis(acetoxymethyl) ester of quin-2. Quin-2 loading inhibited insulin-stimulated glucose transport without affecting basal activity. The ability of insulin to stimulate glucose uptake in quin-2-loaded cells could be partially restored by preincubating cells with buffer supplemented with 1.2 mM CaCl/sub 2/ and the Ca/sup 2 +/ ionophore A23187. These conditions had no effect on basal activity and omission of CaCl/sub 2/ from the buffer prevented the restoration of insulin-stimulated glucose uptake by A23187. Quin-2 loading also inhibited insulin-stimulated glucose oxidation and the ability of insulin to inhibit cAMP-stimulated lipolysis without affecting ...

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The maintenance of a balance between cell gain and cell loss is essential for proper liver function. The exact role of aryl hydrocarbon receptor (AhR) in regulating cell proliferation and apoptosis of liver cells remains unclear, since ligand-dependent activation of AhR has been shown to induce cell cycle arrest, proliferation, differentiation or apoptosis, depending on the cellular model used. AhR can directly interact with retinoblastoma protein in hepatic cells, forming protein complexes that can efficiently block cell cycle progression by inducing G1 arrest, or to induce the expression of inhibitors of cyclin-dependent kinases, such as p271. On the other hand, it has been suggested that AhR could play a stimulatory role in cell proliferation, either directly or by mediating a release from contact inhibition. It is now generally accepted that progenitor cells exist in the liver, are activated in various liver diseases and can form a potential target cell ...

UK PubMed Central (United Kingdom)

The acute acetoclastic methanogenic inhibition of several inorganic and organic arsenicals was assayed. Trivalent species, i.e., methylarsonous acid and arsenite, were highly inhibitory, with 50% inhibitory...Full Text Available

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The mechanisms involved in amino acid and sugar uptake by developing maize kernels were investigated. In the pedicel region of maize kernel, the site of nutrient unloading from phloem terminals, amino acids are accumulated in considerable amounts and undergo significant interconversion. A wide spectrum of enzymatic activities involved in the metabolism of amino acids is observed in these tissues. Subsequently, amino acids are taken up by the endosperm tissue in processes which require energy and the presence of carrier proteins. Conversely, no evidence was found that energy and carriers are involved in sugar uptake. This process of sugar uptake is not inhibited by metabolic inhibitors and shows nonsaturable kinetics, but the uptake is pH-dependent. L-glucose is taken up at a significantly reduced rate in comparison to D-glucose uptake. Based on analysis of radioactivity distribution among sugar fractions after incubations of kernels with ...

Science.gov (United States)

The real-time polymerase chain reaction (PCR) quantification of several vaginal bacterial groups in healthy women and patients developing asymptomatic bacterial vaginosis (BV) and candidiasis (CA) was performed. Statistical analysis revealed that the BV condition is characterised by a great variability among subjects and that it is associated with a significant increase of Prevotella, Atopobium, Veillonella and Gardnerella vaginalis, and a drop in Lactobacillus. On the contrary, the vaginal microflora of healthy women and patients developing CA was found to be homogeneous and stable over time. PMID:18762999

Science.gov (United States)

The emergence of bacterial antibiotic resistance is a growing problem, yet the variables that influence the rate of emergence of resistance are not well understood. In a microfluidic device designed to mimic naturally occurring bacterial niches, resistance of Escherichia coli to the antibiotic ciprofloxacin developed within 10 hours. Resistance emerged with as few as 100 bacteria in the initial inoculation. Whole-genome sequencing of the resistant organisms revealed that four functional single-nucleotide polymorphisms attained fixation. Knowledge about the rapid emergence of antibiotic resistance in the heterogeneous conditions within the mammalian body may be helpful in understanding the emergence of drug resistance during cancer chemotherapy. PMID:21940899

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PMID:10684911

UK PubMed Central (United Kingdom)

BackgroundIt is well established that Legionella pneumophila is a waterborne pathogen; by contrast, the mode of Helicobacter pylori transmission...Full Text Available

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... 84. Fields BS, Haupt T, Davis JP, Arduino MJ, Butler JC. Pontiac fever due to Legionella micdadei from a whirlpool spa: Possible role of bacterial endotoxin. ...

UK PubMed Central (United Kingdom)

The bacterium Serratia marcescens produces a plethora of multicellular shapes of different colorations on solid substrates, allowing immediate visual detection of varieties. Such a...Full Text Available

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Protein isolated from hen egg-white and functions as a bacteriostatic enzyme by degrading bacterial cell walls. First enzyme ever characterized by protein ...

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Energy Technology Data Exchange (ETDEWEB)

Since chlordecone (Kepone, CD) interferes with cardiac Na{sup +} ion translocases, we have studied CD effects on cardiac SR calcium pump activity. SR was isolated from heart ventricles of male Sprague-Dawley rats. Cardiac SR Ca{sup 2+}-ATPase, {sup 45}Ca-uptake and cAMP as well as calmodulin (CaM) dependent protein phosphorylation were measured. Ca{sup 2+}-ATPase was differentiated into low affinity and high affinity forms by measuring the activity using 50 and 0.7 {mu}M free Ca{sup 2+} respectively. CD in vitro inhibited {sup 45}Ca-uptake by SR in a concentration dependent manner with an IC50 value of 7 {mu}M and SR {sup 45}Ca-uptake was totally inhibited at 20-30 {mu}M CD. In agreement with this, both high affinity and low affinity Ca{sup 2+}-ATPases, which are involved in Ca{sup 2+} transport across membranes, were also inhibited by CD in a concentration dependent manner with IC50 values of 0.7 and 3.2 {mu}M ...

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Caffeine and related xanthines were identified as potent stimulators for the bacterial cellulose production in A. xylinum. These compounds are present in several plants whose infusions are useful as culture-medium supplements for this acetobacterium. The proposed target for these native purine-like inhibitory substances is the novel diguanyl nucleotide phosphodiesterase(s) that participates in the bacterial cellulogenic complex.

International Nuclear Information System (INIS)

A nuclear fuel waste disposal vault would not likely be a sterile environment. Bacterial activity would be expected in those areas of the vault conducive to bacterial life, i.e., where effects of heat, moisture content, radiation and compaction would not prevent or severely restrict bacterial life and where suitable and sufficient nutrients would be present. An inventory of bacterial nutrients that would be emplaced 'intentionally' with vault materials (fuel waste, waste containers, buffer and backfill materials) has been made previously. This report assesses bacterial nutrients that would be added 'inadvertently' to a vault in the form of residues of materials used to excavate and operate a vault. Measurements of blasting material residues in the various water supplies, excavated broken rock (muck) and in cores drilled in old and new tunnel walls were made at AECL's Underground ...

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''Paraquat lung'' which is complicated with paraquat poisoning has been a lethal pulmonary pathology presenting intra-alveolar fibrosis, but an effective therapy has not been developed so far. We hypothesized that the type II alveolar cells producing surfactant were damaged by paraquat which was actively accumulated through out the blood by alveolar epithelial cells. To prove this hypothesis, we examined the effect of an intratracheal administration of an artificial lung surfactant (surfacten, Mitsubishi Tanabe Pharma Corporation, Osaka) on mortality in a model of murine paraquat poisoning. Paraquat was given intramuscularly 3 days after the intratracheal surfactant administration. The mice used were C57BL/6J strain and Balb/C strain. The lethal dose, 50% (LD50), of paraquat was about 28 mg/kg in the C57BL/6J strain and about 9 mg/kg in the Balb/C strain, respectively. Mortalities of paraquat poisoning in both strains of mice improved significantly when the mice were pretreated with ...

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Neuronal cell death induced by oxidative stress is correlated with numerous neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and stroke. The causes of sporadic forms of age-related neurodegenerative diseases are still unknown. Recently, a correlation between paraquat exposure and neurodegenerative diseases has been observed. Paraquat, a nonselective herbicide, was once widely used in North America and is still routinely used in Taiwan. We have used differentiated Human Neuroblastoma (SHSY-5Y) cells as an in vitro model to study the mechanism of cell death induced by paraquat. We observed that paraquat-induced oxidative stress in differentiated SHSY-5Y cells as indicated by an increase in the production of cellular reactive oxygen species (ROS). Furthermore, apoptosis was evident as indicated by cellular and nuclear morphology and DNA fragmentation. Interestingly, pretreatment of SHSY-5Y cells with water-soluble Coenzyme ...

Science.gov (United States)

Influenza virus infection during pregnancy has been implicated as one of cause of premature delivery, abortion and stillbirth. We have reported that cultured human fetal membrane chorion cells undergoing apoptosis by influenza virus infection secrete unidentified heat-stable monocyte differentiation-inducing (MDI) factors. In this study, cellular, biological and immunochemical characteristics of MDI factors were investigated using human monocytic leukemia THP-1 cells by nitroblue tetrazolium reduction and cell adhesion assays. The treatment of THP-1 cells with culture supernatants from the influenza virus-infected chorion cells induced the nitroblue tetrazolium reduction ability, which was inhibited by the addition of superoxide dismutase and diphenyleneiodonium chloride, an inhibitor for reduced nicotinamide adenine dinucleotide phosphate oxidase. The phenomenon was also observed in human peripheral blood monocytes and histiocytic leukemia U937 cells, but not in ...

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This article concerns the synergetic effects between an MoO{sub 3} sample composed of crystallites exposing preferentially the (010) basal faces and {alpha}-Sb{sub 2}O{sub 4} in the oxygen-assisted dehydration of 2-butanol at 220 C. The conversion of 2-butanol and the yield to butene improved when MoO{sub 3} was reacted in the presence of {alpha}-Sb{sub 2}O{sub 4}. The origin of the synergism is discussed. When reacted in the absence of {alpha}-Sb{sub 2}O{sub 4}, MoO{sub 3} got over-reduced and fragmented to MoO{sub 2}. MoO{sub 2} is intrinsically less active than MoO{sub 3} thus explaining that the deep reduction of MoO{sub 3} corresponds to its tendency to deactivate. In the presence of {alpha}-Sb{sub 2}O{sub 4}, the formation of MoO{sub 2} is inhibited with, as a consequence, the absence of deactivation. This leads to the synergetic effects obtained with the mechanical mixture of MoO{sub 3} with {alpha}-Sb{sub 2}O{sub 4}. (orig.)

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Multilayer mirrors for the extreme ultraviolet (EUV) are keyelements for numerous applications of coherent EUV sources such as newtabletop lasers and free-electron lasers. However the field ofapplications is limited by the radiation and thermal stability of themultilayers. Taking into account the growing power of EUV sources thestability of the optics becomes crucial. To overcome this problem it isnecessary to study the degradation of multilayers and try to increasetheir temporal and thermal stability. In this paper we report the resultsof detailed study of structural changes in Sc/Simultilayers when exposedto intense EUV laser pulses. Various types of surface damage such asmelting, boiling, shockwave creation and ablation were observed asirradiation fluencies increase. Cross-sectional TEM study revealed thatthe layer structure was completely destroyed in the upper part ofmultilayer, but still survived below. The layers adjacent tothe substrateremained intact even through the ...

International Nuclear Information System (INIS)

The purpose was to study the toxicity of drugs known to generate free radicals on isolated pancreatic islets. The accumulattion of "8"6Rb"+ by mouse pancreatic islets was measured in vitro. Exposing the islets to 6-hydroxydopamine, minhydrin, or phenazine methosulphate + NADH inhibited the Rb"+ uptake, whereas paraquat or acetylphenylhydrazine had no effect. This effect of 6-hydroxydopamine was prevented by either of the hydroxyl radical scavengers, sodium benzoate and mannitol, but not by the non-scavenger,urea; ninhydrin was partially protected against by mannitol but not by benzoate. Protection against 6-hydroxydopamine was also afforded by D-glucose but not by L-glucose or 3-O-methyl-D-glucose; none of the sugars protected against ninhydrin. In damaging islet beta-cells and in being protected against by D-glucose, 6-hydroxydopamine closely resembles the diabetogenic drug, alloxan. It is suggested that protection against alloxan may involve both glucose ...

International Nuclear Information System (INIS)

The atomic explosions in Hiroshima and Nagasaki made the name radiation itself become a nightmare. Notwithstanding this, radiation continued to serve the mankind specially in diagnosis of several human diseases and in the treatment of intractable malignancies. With their latest research tools biologists have now shown a significant shift in the earlier paradigm; even the concept that radiation initiates cancer appears to be no longer tenable. On the contrary, selective radiation doses inhibit growth of cancer cells and radiation in combination with many chemotherapeutic drugs, radiosensitizing chemicals and/or hyperthermia, is emerging as a new modality for cancer treatment which offers high therapeutic advantages. In addition, the deleterious effects of radiation can now be strategically counter poised by the use of many drugs and chemicals. This has been possible by the newer insights gained in the mechanism of biological effects of ...

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As part of their corporate policy on environmental protection, Chevron, has taken an approach to work collaboratively with other industry members, universities and government agencies in phytoremediation research. The petroleum industry is interested in the integration of phytoremediation with the many biotechnology treatment technologies currently being used by the industry. Phytoremediation is a complex technology that does not just transfer wastes to another site, but offers in-situ final use and disposal treatment at sites anywhere in the world. Sites for potential remediation range from abandoned large refineries, chemical plants, or small urban gas stations. Research has focused on the cleanup of metals and hydrocarbons in diverse types of soil, water and groundwater conditions. This includes research into remediation of petroleum contaminants such as total petroleum hydrocarbon (TPH), polynuclear aromatic hydrocarbons as well as benzene in soil and the ...

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Many assays for oncogenic transformation have been developed ranging from those in established rodent cell lines where morphological alteration is scored, to those in human cells growing in nude mice where tumor invasiveness is scored. In general, systems that are most quantitaive are also the least relevant in terms of human carcinogenesis and human risk estimation. The development of cell culture systems has made it possible to assess at the cellular level the oncogenic potential of a variety of chemical, physical and viral agents. Cell culture systems afford the opportunity to identify factors and conditions that may prevent or enhance cellular transformation by radiation and chemicals. Permissive and protective factors in radiation-induced transformation include thyroid hormone and the tumor promoter TPA that increase the transformation incidence for a given dose of radiation, and retinoids, selenium, vitamin E, and 5-aminobenzamide that inhibit the expression ...

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Under typical conditions found in Pressurized Fluidized Bed Combustion (PFBC), the calcination reaction of limestones is thermodynamically inhibited, and the sorbent reacts with SO{sub 2} by a direct mechanism. Direct sulfation reactivity of different Spanish sorbents was studied by high-pressure thermogravimetric analysis. It was found that the physical structure of the surface of the particles influence the sulfation behaviour of the sorbents. Total pore volume and pore surface area correlated well with the reactivity of the sorbents. Temperatures between 800 and 925{degree}C, and pressure between 12 and 25 bar, promoted an increase in reactivity, while the gas composition had no effect when changed from 15% CO{sub 2}, 3% O{sub 2}, 0.5% SO{sub 2}, balance N{sub 2} to 12% CO{sub 2}, 7% O{sub 2}, 0.5% SO{sub 2}, balance N{sub 2}. It was found that the unreacted shrinking core model could not satisfactorily describe the sulfation reaction under ...

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It was previously reported that the tritium tracer method is useful for the quantitative consideration of hydrogen behavior in coal during coal liquefaction reaction. Tetralin is excellent hydrogen donating solvent, and is considered as one of the model compounds of coal. In this study, effects of H2S and H2O on the hydrogen exchange reaction between tetralin and gaseous hydrogen labeled by tritium were investigated. It was suggested that the conversion of tetralin and the hydrogen exchange reaction between gaseous hydrogen and tetralin proceed through the radical reaction mechanism with a tetralyl radical as an intermediate product. When H2S existed in this reaction, the hydrogen exchange yield increased drastically without changing the conversion yield. This suggested that the hydrogen exchange reaction proceeds even in the reaction where radical does not give any effect. In the case of H2O addition, the conversion yield and hydrogen exchange rate decreased into ...

International Nuclear Information System (INIS)

The present work was carried out to illuminate the relation between high cholesterol diet and incidence of prostate caner. Also, in this study, the effect of DHEA, selenium or oxygen therapy were tested in order to show to what extent they are valid to ameliorate the deleterious effects of prostate cancer. The obtained results revealed that prostate cancer caused a significant (p<0.01) elevation of TAP, PAP, PSA, total cholesterol, triglyceride, HDL-cholesterol and LDL-cholesterol and prostate COX-2, whereas, testosterone, free testosterone, DHEA-S, FT_4 and FT_3 were decreased significantly as compared with the corresponding levels in control rats in both normal and high cholesterol diet. Supplementation of DHEA, selenium or oxygen therapy ameliorated all variables recorded herein but, their values did not revert to normal. Any how, the results of this investigation showed that the above mentioned antioxidants possess potential benefits in lessening number of risk factors in blood ...

International Nuclear Information System (INIS)

Exposure of cells to light of less than 320 nanometers wavelengths may lead to lethal lesions and perhaps carcinogenesis. Many organisms have evolved mechanisms to repair U.V. light-induced damage. Organisms such as deep-sea bacteria are presumably never exposed to U.V. light and perhaps occasionally to visible from bioluminescence. Thus, the repair of U.V. damage in deep-sea bacterial DNA might be inefficient and repair by photoreactivation unlikely. The bacteria utilized in this investigation are temperature sensitive and barophilic. Four deep-sea isolates were chosen for this study: PE-36 from 3584 m, CNPT-3 from 5782 m, HS-34 from 5682 m, and MT-41 from 10,476 m, all are from the North Pacific ocean. The deep-sea extends from 1100 m to depths greater than 7000 m. It is a region of relatively uniform conditions. The temperature ranges from 5 to -1"0C. There is no solar light in the deep-sea. Deep-sea bacteria are sensitive to U.V. light; in ...

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The fine scale mechanical probing capability of NI-AFM was used to examine hydrogen interaction with plasticity. To realize this, an electrochemical three electrode setup was incorporated into the NI-AFM. The developed ECNI-AFM is capable of performing nanoindentation as well as imaging surfaces inside electrolytes. The developed ECNI-AFM setup was used to examine the effect of cathodically charged hydrogen on dislocation nucleation in pure metals and alloys. It was shown that hydrogen reduces the pop-in load in all of the tested materials except Cu. The reduced pop-in load can be interpreted as the HELP mechanism. Classical dislocation theory was used to model the homogeneous dislocation nucleation and it was shown that H reduces the activation energy for dislocation nucleation in H sensitive metals which are not undergoing a phase transformation. The activation energy for dislocation nucleation is related to the material specific parameters; ...

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Breast cancer progression is characterized by inappropriate cell growth. Normal cells cease growth after a limited number of cell divisions--a process called cellular senescence-while tumor cells may acquire the ability to proliferate indefinitely (immortality). Inappropriate expression of specific oncogenes in a key cellular signaling pathway (Ras, Raf) can promote tumorigenicity in immortal cells, while causing finite lifespan cells to undergo a rapid senescence-like arrest. We have studied when in the course of transformation of cultured human mammary epithelial cells (HMEC), the response to overexpressed oncogenic Raf changes from being tumor-suppressive to tumor enhancing, and what are the molecular underpinnings of this response. Our data indicate: (1) HMEC acquire the ability to maintain growth in the presence of oncogenic Raf not simply as a consequence of overcoming senescence, but as a result of a newly discovered step in the process of immortal transformation uncovered by ...

Science.gov (United States)

Norepinephrine stimulates the growth of a range of bacterial species in nutritionally poor SAPI minimal salts medium containing 30% serum. Addition of size-fractionated serum components to SAPI medium indicated that transferrin was required for norepinephrine stimulation of growth of Escherichia coli. Since bacteriostasis by serum is primarily due to the iron-withholding capacity of transferrin, we considered the possibility that norepinephrine can overcome this effect by supplying transferrin-bound iron for growth. Incubation with concentrations of norepinephrine that stimulated bacterial growth in serum-SAPI medium resulted in loss of bound iron from iron-saturated transferrin, as indicated by the appearance of monoferric and apo- isoforms upon electrophoresis in denaturing gels. Norepinephrine also caused the loss of iron from lactoferrin. The pharmacologically inactive metabolite norepinephrine 3-O-sulfate, by contrast, did not result in ...

British Library Electronic Table of Contents (United Kingdom)

This study investigates the turnover of polysaccharides by heterotrophic bacterioplankton in the northern Bay of Biscay, a productive marine system on the continental margin of the temperate Atlantic Ocean. Bacterial biomass production (BBP) near the surface ranged from 0.5 to 25.7 nmol C L?1 h?1 during small phytoplankton blooms in May and June that occurred after the main spring bloom. A direct relationship between BBP and total polysaccharides strongly suggests the dependence of bacterial growth on the availability of semi-labile organic matter. Concentrations of combined glucose as well as rate constants of extracellular glucosidase activity and glucose uptake were determined to estimate the actual carbon fluxes from bacterial polysaccharide turnover. Results reveal that ...

British Library Electronic Table of Contents (United Kingdom)

The colonization of an implant surface by bacteria is an extremely important medical problem, which often leads to the failure of medical devices. Modern surface modification techniques, such as ion implantation, can confer to the surfaces very different properties from those of the bulk underlying material. In this work, austenitic stainless steel 316 LVM has been superficially modified by Si^+ ion implantation. The effect of surface modification on the biocompatibility and bacterial adhesion to 316 LVM stainless steel has been investigated. To this aim, human mesenchymal stem cells (hMSCs), as precursor of osteoblastic cells, and bacterial strains relevant in infections related to orthopedic implants, i.e., Staphylococcus aureus and Staphylococcus epidermidis, have been assayed. For the ...

UK PubMed Central (United Kingdom)

Latent inhibition (LI) manifests as poorer conditioning to a CS that has previously been presented without consequence. There is some evidence that LI can be potentiated by reduced mesoaccumbal dopamine...Full Text Available

UK PubMed Central (United Kingdom)

Mycophenolate mofetil (MMF) is an immunosuppressive drug that acts as a selective inhibitor of inosine monophosphate dehydrogenase (IMPDH). MMF has recently been shown to inhibit the enzymatic activity...Full Text Available

UK PubMed Central (United Kingdom)

Spike-timing-dependent plasticity (STDP), a form of Hebbian plasticity, is inherently stabilizing. Whether and how GABAergic inhibition influences STDP is not well understood. Using a model neuron driven...Full Text Available

UK PubMed Central (United Kingdom)

As the result of genetic alterations and tumor hypoxia, many cancer cells avidly take up glucose and generate lactate through lactate dehydrogenase A (LDHA), which is encoded by a target gene of c-Myc...Full Text Available

UK PubMed Central (United Kingdom)

The structural features required for xyloglucan oligosaccharides to inhibit 2,4-dichlorophenoxyacetic acid-stimulated elongation of pea stem segments have been investigated. A nonasaccharide (XG9)...Full Text Available

UK PubMed Central (United Kingdom)

Methyl fluoride is frequently used to specifically inhibit acetoclastic methanogenesis, thus allowing determination of the relative contribution of acetate versus H₂/CO₂ to total...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundInadequate platelet inhibition despite aspirin and clopidogrel therapy during and after a percutaneous coronary intervention is associated with an impaired clinical outcome....Full Text Available

UK PubMed Central (United Kingdom)

Low concentrations of sugars altered the sensitivity of seed germination to inhibition by exogenous abscisic acid (ABA). Germination of wild-type and ABA-insensitive (abi) Arabidopsis...Full Text Available

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PMID:20856939

International Nuclear Information System (INIS)

... aluminum calcium calcium 45 cations citric acid corrosion inhibition radiation

International Nuclear Information System (INIS)

Azobenzene dyes are effective inhibitors for austenitic 304 L and 316 L stainless steel corrosion in high acidic medium up to 7N. A good efficiency is obtained from weight loss and electrochemical Rsub(p) measurements in hydrochloric acid, while no inhibition is observed in sulfuric solutions. Transformation from the primarily azobenzene to other compounds give rise to enhanced protection of steel samples, and probable structures of the inhibiting species are proposed in view of our results.

UK PubMed Central (United Kingdom)

BackgroundDinoflagellates are unicellular, often photosynthetic protists that play a major role in the dynamics of the Earth's oceans and climate. Sequencing of dinoflagellate nuclear...Full Text Available

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Many bacterial pathogens produce extracellular proteases that degrade the extracellular matrix of the host and therefore are involved in disease pathogenesis. Dichelobacter nodosus...Full Text Available

UK PubMed Central (United Kingdom)

A previous report of high levels of members of the domain Archaea in Antarctic coastal waters prompted us to investigate the ecology of Antarctic planktonic prokaryotes. rRNA hybridization...Full Text Available

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The pathogenesis of Pseudomonas aeruginosa disseminated infections depends on bacterial interaction with blood vessels. We have hypothesized that in order to traverse the endothelial barrier, bacteria...Full Text Available

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Adaptive radiation is the rapid origination of multiple species from a single ancestor as the result of concurrent adaptation to disparate environments. This fundamental evolutionary process is considered...Full Text Available

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Type 1 pilus directs bladder epithelial binding and invasion by uropathogenic Escherichia coli (UPEC) in the initial stage of cystitis, but the bacterial determinants of postinvasion...Full Text Available

UK PubMed Central (United Kingdom)

Macrophage activation by the proinflammatory cytokine interferon-γ (IFN-γ) is a critical component of the host innate response to bacterial pathogenesis. However, the precise nature...Full Text Available

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Bacterial processes in soil, including biodegradation, require contact between bacteria and substrates. Knowledge of the three-dimensional spatial distribution of bacteria at the microscale is necessary...Full Text Available

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... were erroneous. The oriental rat flea, Xenopsylla cheopis Rothschild, is considered to be the primary vector of ... laboratory and production of Weigl's exanthematous typhus vaccine. In Maintenance of hum...

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The gram-negative plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria is the causative agent of bacterial spot disease in pepper and tomato plants, which leads to economically...Full Text Available

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To define the import pathway for apoiso-1-cytochrome c in vivo, the coding region for bacterial chloramphenicol acetyltransferase (CAT) or yeast copper metallothionein (CuMT) was fused to the carboxy...Full Text Available

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BackgroundThe human bacterial pathogen Campylobacter jejuni contains two subspecies: C. jejuni subsp. jejuni (Cjj)...Full Text Available

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Clindamycin concentrations in gingival crevicular fluid and in blood were determined over a 7-h period and were related to the minimal inhibitory concentrations of this agent for 340 bacterial strains...Full Text Available

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Purpose of reviewSevere congenital neutropenia (SCN) is a primary immunodeficiency in which lack of neutrophils causes inadequate innate immune host response to bacterial...Full Text Available

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Clostridium perfringens type A food poisoning is the second most commonly identified bacterial food-borne illness. Sporulation contributes to this disease in two ways: (i) most food-poisoning...Full Text Available

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Bacterial nitric oxide synthases (bNOS) are present in many Gram-positive species and have been demonstrated to synthesize NO from arginine in vitro and in vivo. However, the physiological role...Full Text Available

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Rumen-cannulated cows (n = 4) were fed successively silage made from either conventional or genetically modified (GM) maize. Results revealed no effects of GM maize on the dynamics...Full Text Available

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Many pathogens colonize different anatomical sites, but the selective pressures contributing to survival in the diverse niches are poorly understood. Group A Streptococcus (GAS) is...Full Text Available

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Caries is a multifactorial disease, and studies aiming to unravel the factors modulating its etiology must consider all known predisposing factors. One major factor is bacterial colonization,...Full Text Available

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In order to identify novel high value antibacterial targets it is desirable to delineate whether the inactivation of the target enzyme will lead to bacterial death or stasis. This knowledge is particularly...Full Text Available

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Biodegradation/solubilization of coal is described. The degradation of dibenzothiophene by two bacterial strains is reported. The effects of adding salicylate to the treatments was also investigated. 2 figs., 5 tabs. (CBS)

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BackgroundOceans are iron-deficient and nutrient-poor environments. These conditions impart limitations on our understanding of and our ability to identify microorganisms from the...Full Text Available

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In Iran, microscopic examination of skin scrapings from 2202 individuals with clinically diagnosed cutaneous leishmaniasis (CL) lesions revealed the presence of amastigotes in 1123 cases (51.0%). Bacteriological...Full Text Available

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The CD1 family of proteins binds self and foreign glycolipids for presentation to CD1-restricted T cells. To identify previously uncharacterized active CD1 ligands, especially those of microbial origin,...Full Text Available

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BackgroundSepsis or bacteraemia, however rare, is a significant cause of high mortality and serious complications in children. In previous studies skin disease or skin infections...Full Text Available

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The distribution and activity of communities of sulfate-reducing bacteria (SRB) and methanogenic archaea in two contrasting Antarctic sediments were investigated. Methanogenesis dominated in freshwater...Full Text Available

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BackgroundBacterial constituents, such as Gram-negative derived lipopolysaccharide (LPS), can initiate inflammatory bone loss through induction of host-derived inflammatory...Full Text Available

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The accumulation of α-1,4-polyglucans is an important strategy to cope with transient starvation conditions in the environment. In bacteria and plants, the synthesis of glycogen and starch occurs...Full Text Available

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Bacterial artificial chromosome (BAC) clones are effective mapping and sequencing reagents for use with a wide variety of small and large genomes. This report describes the development of a physical...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The transfer of fish from field to laboratory facilities or their propagation in closed or restricted systems frequently results in bacterial infection and ultimately large-scale mortality. In attemps to alleviate this problem, we have added tetracycline hydrochloride to the water prophylactically (pretreating tanks before wild fish were added) and therapeutically (treating tanks after bacterial outbreaks were detected.) In the present study, we examined the effect of tetracyline hydrochloride on the critical thermal maximum (CTM) of the common shiner (Notropis cornutus).

Science.gov (United States)

Autophagy is an intracellular recycling route in eukaryotes whereby organelles and cytoplasm are sequestered in vesicles, which are subsequently delivered to the vacuole for breakdown. The process is induced by various nutrient-responsive signaling cascades converging on the Autophagy-Related1 (ATG1)/ATG13 kinase complex. Here, we describe the ATG1/13 complex in Arabidopsis thaliana and show that it is both a regulator and a target of autophagy. Plants missing ATG13 are hypersensitive to nutrient limitations and senesce prematurely similar to mutants lacking other components of the ATG system. Synthesis of the ATG12-ATG5 and ATG8-phosphatidylethanolamine adducts, which are essential for autophagy, still occurs in ATG13-deficient plants, but the biogenesis of ATG8-decorated autophagic bodies does not, indicating that the complex regulates downstream events required for autophagosome enclosure and/or vacuolar delivery. Surprisingly, levels of the ATG1a and ATG13a phosphoproteins drop ...

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The mechanism of cobalt uptake was investigated using cells of the giant alga Chara corallina in which it is possible to resolve separately uptake by the cell wall and actual influx across the cell membrane. The absorption of {sup 60}Co by Chara cells appeared to saturate within 2 h. but this was mainly due to rapid uptake into the cell wall which accounted for 87-92% of the total activity. Even after prolonged desorption most of the cell-associated {sup 60}Co was found on the cell wall. The intracellular distribution of absorbed {sup 60}Co was investigated by fractionating the cell into cytoplasm and vacuole. It was shown that {sup 60}Co influx to the vacuole occurs simultaneously with influx to the cytoplasm. The transported species appears to be Co{sup 2+} rather than the less charged Co(OH){sup +} or Co(O){sub 2}. {sup 60}Co influx is pH dependent (optimum pH 7-9), and is sensitive to some other divalent metals. Influx from solutions containing 1 {mu}M {sup ...

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Studies were conducted to quantitate the evolution of nitrogen oxides (NO/sub (x)/) from soybean (Glycine max (L.) Merr.) leaves during in vivo nitrate reductase (NR) assays with aerobic and anaerobic gas purging. Anaerobic gas purging (N/sub 2/ and argon) consistently resulted in greater NO/sub (x)/ evolution than did aerobic gas purging (air and O/sub 2/). The evolution of NO/sub (x)/ was dependent on gas flow rate and on NO/sub 2//sup -/ formation in the assay medium; although a threshold level of NO/sub 2//sup -/ appeared to exist beyond which the rate of NO/sub (x)/ evolution did not increase further. The loss of NO/sub (x)/ from in vivo NR assays under gas purging explains partially, but not stoichiometrically, the decrease of NO/sub 2//sup -/ accumulation in in vivo NR assay medium with young soybean leaves. The lack of stoichiometry between NO/sub (x)/ evolution and apparent NO/sub 2//sup -/ loss suggests that other mechanisms are also involved in loss of ...

International Nuclear Information System (INIS)

As an important radioisotope in nuclear industry and other fields, americium-241 is one of the most serious contamination concerns duo to its high radiation toxicity and long half-life. In this experiment, the biosorption of "2"4"1Am from solution by a fungus, Saccharomyces cerevisiae (S. cerevisiae), and the effects of various experimental conditions on the biosorption and the mechanism were explored. The preliminary results showed that S. cerevisiae is a very efficient biosorbent. An average of more than 99% of the total "2"4"1Am could be removed by S. cerevisiae of 2.1g/L (dry weight) from "2"4"1Am solutions of 2.22MBq/L -555 MBq/L (Co). The adsorption equilibrium was achieved within 1 hour and the optimum pH ranged 1-3. The culture times of more than 16 hours were suitable and the efficient adsorption of 241Am by the S. cerevisiae could be noted. The biosorption of 241Am by the decomposed cell wall, protoplasm or cell membrane of S. cerevisiae was same ...

Science.gov (United States)

DNA polymerase gamma from purified nuclei of EMT-6 cells (mice) seems to be identical to the mitochondrial DNA polymerase from the same source following several criteria. These two enzyme activities are strongly inhibited by ethidium bromide and acriflavin, while proflavin, acridine orange, daunomycin and chloroquine inhibition is less pronounced. In the case of DNA polymerases alpha and beta very little inhibition by ethidium bromide was observed. Intercalation of this dye in a poly dA-dT 12-18 template-primer was studied spectrophotometrically under conditions similar to those in the in vitro DNA polymerase assay. The polymerase assay. The inhibition by this drug of the mitochondrial DNA polymerase gamma activity was shown to be competitive at varying concentrations of TTP while the inhibition was of the non-competitive type at different concentrations of poly dA-dT 12-18. We ...

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Inhibition efficiency of some water-soluble hydrazones for C-steel corrosion in hydrochloric acid has been tested by weight loss, polarisation measurements and open circuit technique. The inhibition effect was attributed to the adsorption of the additives on the C-steel surface as supported by adsorption measurements at Pt electrode using cyclic voltammetry. Electrochemical measurements indicated that all the additives behave as cathodic-type inhibitors. The data obtained fit well to both the Temkin adsorption isotherm and the kinetic-thermodynamic model. The inhibition behaviour and its order were explained with the help of the proposed skeletal representation.

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Corrosion inhibition of iron in H2SO4 by polyacrylic acid (PAA) was investigated using electrochemical techniques at 30degreeC. Results obtained indicate that PAA inhibited the corrosion of iron in the acid medium. Inhibition efficiency increases with increase in PAA concentration and synergistically enhanced on addition of iodide ions. Potentiodynamic polarization results suggest that PAA functions as a modest cathodic inhibitor. The adsorption of PAA onto the iron surface followed Temkin adsorption isotherm. FTIR analysis revealed that the synergistic effect due to co-adsorption of iodide ions and PAA is co-operative in nature.

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Regulatory T cells are proposed to play a central role in the maintenance of immunological tolerance in the periphery, and studies in many animal models demonstrate their capacity to inhibit inflammatory...Full Text Available

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The binding of iodine-labelled plasminogen to Helicobacter pylori CCUG 17874 was characterized. Inhibition of the binding was observed after preincubation of H. pylori...Full Text Available

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The effect of low concentrations of nalidixic acid on ribonucleic acid (RNA) synthesis in Escherichia coli was examined. It was observed that RNA synthesis in exponentially growing...Full Text Available

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No abstract prepared.

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Current models of DNA repair of biological damage are reviewed correlating the similarity between carcinogenesis and mutagenesis theories. (PCS)

International Nuclear Information System (INIS)

The combination of zero-valent iron (Fe0) and iron oxide-coated sand (IOCS) was used to remove Cr(VI) and As(V) from groundwater in this study. The efficiency and the removal mechanism of Cr(VI) and As(V) by using this combination, with the influence of humic acid (HA), were investigated using batch experiments. Results showed that, compared to using Fe0 or IOCS alone, the Fe0-IOCS can perform better on the removal of both Cr(VI) and As(V). Metal extraction studies showed that As(V) was mainly removed by IOCS and iron corrosion products while Cr(VI) was mainly removed by Fe0 and its corrosion products. Competition was found between Cr(VI) and As(V) for the adsorption sites on the iron corrosion products. HA had shown insignificant effects on Cr(VI) removal but some effects on As(V) removal kinetics. As(V) was adsorbed on IOCS at the earlier stage, but adsorbed/coprecipitated with the iron corrosion products at the later stage. - Research Highlights: ? Fe0-IOCS is ...

International Nuclear Information System (INIS)

"2"0"3Pb(NO_3)_2 was administered i.v. to pregnant C57BL mice at different stages, from day 8 to day 18 of gestation. The whole animals or excised uteri were subjected to autoradiography or were autopsied for scintillation counting of excised organs. Lead appeared in embryonic and fetal tissues at all stages of gestation. Early (approx. day 8-11) lead was restricted mainly to the embryonic blood, suggesting that free lead was essentially not transferred to the embryo but may have been incorporated in the embryonic hemoglobin when the erythrocytes were formed in the yolk sac placenta (an extraembryonic membrane). From day 12 and later, an uptake was seen in the liver and the cartilaginous skeleton, and from day 14, a strong accumulation was found in calcified bone. This means that the overall fetal concentration increases successively with gestational age of the conceptus. The uptake in fetal liver may be related to the erythropoiesis taking place in the liver in later gestation. While ...

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A three-dimensional, three-phase, multiple-component numerical simulator was developed to investigate transport and growth of microorganisms in porous media and the impacts of microbial activities on oil recovery. The microbial activities modeled in this study included: (1) growth, retention, chemotaxis, and end product inhibition of growth, (2) the formation of metabolic products, and (3) the consumption of nutrients. Major mechanisms for microbial enhanced oil recovery (MEOR) processes were modeled as follows: (1) improvement in sweep efficiency of a displacement process due to in situ plugging of highly-permeable production zones by cell mass or due to improved mobility control achieved by increasing the viscosity of the displacing fluid with a biopolymer, and (2) solubilization and mobilization of residual oil in porous media due to the reduction of the interfacial tension between oleic and aqueous phases by the production of a ...

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The Hyperion project was developed to determine an algorithm for assessing the risk of hydrate plug formation in the pipeline transport oil-water-gas mixtures at low temperatures. The project is a collaboration between physicists, chemists and engineers within the petroleum industry. This paper provided an overview of the project and outlined results obtained as the project entered its third and final year. The main objective of the project has been to understand the inherent mitigation effects of some oils on gas hydrate formation as well as to develop methods of predicting the risk of hydrate plugging. To date, the project has extracted and studied natural inhibiting components (NICs) in oils. Molecular modelling techniques have been used to study hydrate and fluid interfaces in order to estimate the driving force of agglomeration and growth through mechanical surface stress and measurement of surface wave fluctuations. A scheme is also being ...

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The present study was designed to investigate, in more detail, the mechanism of lead transport by the gastrointestinal tract and particularly the similarities or dissimilarities between lead and calcium in this process. The absorption of these metals was determined in 3-week-old white Leghorn cockerels, raised on a commercial diet or special diets, using an in vivo ligated loop procedure. The dose administered into the loop usually contained 0.5 ..mu..Ci /sup 203/Pb (and/or 0.1 ..mu..Ci /sup 47/Ca), 0.01 mM lead acetate (and/or 1 mM CaCl/sub 2/) in 0.5 ml of 0.15 M NaCl, pH 6.5. It was shown that lead is rapidly taken up by the intestinal tissue, and only slowly transferred into the circulation whereas calcium, also accumulated rapidly by the tissue, is rapidly released from the tissue in the serosal direction. The absorption processes of these cations show similar responses to various experimental conditions (low calcium intake, age of the animal, pH of the dosing ...

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Cold plasma nitriding treatment was performed to improve the corrosion resistance of C38 carbon steel. Nitriding process was conducted using a radiofrequency nitrogen plasma discharge for different times of treatment on non-heated substrates. The modification of the corrosion resistance characteristic of the C38 steel due to the treatment in acid medium (1 M HCl) were investigated by gravimetric and electrochemical tests such as potentiodynamic polarisation curves and electrochemical impedance spectroscopy (EIS). It was shown that the plasma nitriding treatment improves the corrosion resistance. Indeed, in the gravimetric tests, nitrided samples showed lower weight loss and lower corrosion rate in comparison to untreated one. In the Tafel polarisation tests, the nitrided samples showed greatly reduced corrosion current densities, anodic dissolution and also retarded the hydrogen evolution reaction. Using EIS method, an adequate structural model of the interface was used and the values ...

International Nuclear Information System (INIS)

Combination of radiotherapy and chemotherapy (CRC) is actually one important way of research in oncology. Theoretical advantages are: (1) Spatial cooperation; (2) Additivity, which is only obtained if the toxicity of each modality are different; (3) Supra-additivity, which needs a rigorous in vitro definition; the only way to prove it is to make an isobologram analysis. This model has however, some limitations: qualitative variable could not be used, results could be different, depending on the cell line and isoeffect chosen...In fact, a supra-additivity was only demonstrated for cis platinum and etoposide. Interactions mechanisms were: (1) at the molecular level, creation of new lesions or inhibition of radiation lesions repair; (2) At the cellular level, either cytokinetic cooperation with S-phase dependent drugs, or synchronization for the drugs which blocked the cells in M-phase; (3) At the tissular level, reoxygenation, cycle ...

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This study is aimed at exploring the possible mechanism of hypnosis-enhancing effect of HgS or cinnabar (a traditional Chinese medicine containing more than 95% HgS) in mice treated with pentobarbital. We also examined whether the effect of HgS is different from that of the well-known methyl mercury (MeHg). After a short period (7 days) of oral administration to mice, a nontoxic dose (0.1 g/kg) of HgS not only significantly enhanced pentobarbital-induced hypnosis but also attenuated tolerance induction; while a higher dose (1 g/kg) of HgS or cinnabar exerted an almost irreversible enhancing effect on pentobarbital-hypnosis similar to that of MeHg (2 mg/kg) tested, which was still effective even after 10 or 35 days cessation of administration. To study comparatively the effects of different mercury forms from oral administration of MeHg and HgS on membrane ATPase activities of experimental mice, analysis of the Hg content in the cerebral cortex revealed that ...

International Nuclear Information System (INIS)

To investigate the growth inhibitory effects, and the underlying mechanism of human colon cancer cell (HT-29) death, induced by a new synthetic bile derivative (HS-1200). Human colon cancer cells (HT-29), in exponential growth phase, were treated with various concentrations of a new synthetic bile acid derivative (HS-1200). The growth inhibitory effects on HT-19 cells were examined using a trypan blue exclusion assay. The extent of apoptosis was determined using agarose gel electrophoresis, TUNEL assays and Hoechst staining. The apoptotic cell death was also confirmed by Western blotting of PARP, caspase-3 and DNA fragmentation factor (DFF) analysis. To investigate the involvement of mitochondria, we employed immunofluorescent staining of cytochrome c and mitochondrial membrane potential analyses. The dose required for the half maximal inhibition (IC_5_0) of the HT-29 cell growth was 100 #approx# 150 #mu# M of HS-1200. Several changes, ...

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The two-compartment radioassay for microbial kinetics based on continuous measurement of the {sup 14}CO{sub 2} released by bacterial metabolism of 14C-labeled substrate offers a valuable approach to testing the potency of antimicrobial drugs. By using a previously validated radioassay with gram-positive and gram-negative bacteria, a group of protein synthesis inhibitors was evaluated for their effect on microbial growth kinetics. All tested drugs induced changes in both the slopes and intercepts of the growth curves. An exponential growth model was applied to quantify the drug effect on the processes of bacterial {sup 14}CO{sub 2} liberation and cell generation. The response was measured in terms of a generation rate constant. A linear dependence of the generation rate constant on the dose of spectinomycin was observed with Escherichia coli. Sigmoidal-shaped curves were found in the assays of chloramphenicol and tetracycline. The implications ...

British Library Electronic Table of Contents (United Kingdom)

A comprehensive and highly selective method for detecting in bacterial supernatants a modified sulfur nucleoside, S-adenosyl-L-methionine (SAM), and its metabolites, i.e., S-adenosylhomocysteine (SAH), adenosine (Ado), 5prime-deoxy-5prime-methylthioadenosine (MTA), adenine (Ade), S-adenosyl-methioninamine (dcSAM), homocysteine (Hcy) and methionine (Met), was developed. The method is based on reversed-phase liquid chromatography with positive electrospray ionization (ESI+) coupled to a hybrid linear quadrupole ion trap (LTQ) and 7-T Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). A gradient elution was employed with a binary solvent of 0.05 M ammonium formate at pH 4 and acetonitrile. The assay involves a simultaneous cleanup of cell-free bacterial broths by solid-pha...

British Library Electronic Table of Contents (United Kingdom)

Objective To compare matrix metalloproteinase (MMP)-8 and MMP-9 levels in the vaginal secretions of pregnant women with or without asymptomatic bacterial vaginosis (BV). Methods In this study, vaginal levels and molecular forms of MMP-8 and MMP-9 were studied in 36 pregnant women between 28 and 34 weeks of gestation with asymptomatic BV and 41 pregnant women, matched for gestational age, without BV. Results Vaginal MMP-8 concentrations were significantly higher (P = .023) in BV-positive women. There was no significant difference in MMP-9 levels between healthy pregnant controls and BV-positive pregnant women. The presence of MMP-8 was confirmed by a 38-kd band on Western blots. Conclusions Our findings show that BV is associated with increased levels of MMP-8 in vaginal fluid. Increased pr...

British Library Electronic Table of Contents (United Kingdom)

Eugenol, the principal chemical component of clove oil from Eugenia aromatica has been long known for its analgesic, local anesthetic, anti-inflammatory, and antibacterial effects. The interaction of the eugenol with ten different hydrophobic and hydrophilic antibiotics was studied against five different Gram negative bacteria. The MIC of the combination was found to decrease by a factor of 5-1000 with respect to their individual MIC. This synergy is because of the membrane damaging nature of eugenol, where 1mM of its concentration is able to damage nearly 50% of the bacterial membrane. Eugenol was also able to enhance the activities of lysozyme, Triton X-100 and SDS in damaging the bacterial cell membrane. The hydrophilic antibiotics such as vancomycin and b-lactam antibiotics which have ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Plant pathogenic bacteria of the genus Xanthomonas cause a variety of diseases in economically important monocotyledonous and dicotyledonous crop plants worldwide. Successful infection and bacterial multiplication in the host tissue often depend on the virulence factors secreted including adhesins, polysaccharides, LPS and degradative enzymes. One of the key pathogenicity factors is the type III secretion system, which injects effector proteins into the host cell cytosol to manipulate plant cellular processes such as basal defense to the benefit of the pathogen. The coordinated expression of bacterial virulence factors is orchestrated by quorum-sensing pathways, multiple two-component systems and transcriptional regulators such as Clp, Zur, FhrR, HrpX and HpaR. Furthermore, virule...

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This paper reports the results of leaching experiments conducted with and without Thiobacillus ferroxidans at the same conditions in solution. The extent of leaching of ZnS with Bacteria is significantly higher than that without bacteria at high concentrations of ferrous ions. A porous layer of elemental sulfur is present on the surfaces of the chemically leached particles, which no sulfur is present on the surfaces of the bacterially leached particles. The analysis of the data using the shrinking-core model shows that the chemical leaching of ZnS is limited by the diffusion of ferrous ions through the sulfur product layer at high concentrations of ferrous ions. The analysis of the data shows that diffusion through the product layer does not limit the rate of dissolution when bacteria are present. This suggests that the action of T.ferroxidans in oxidizing the sulfur formed on the particle surface is to remove the barrier to diffusion by ferrous ions.

British Library Electronic Table of Contents (United Kingdom)

Abstract The efficacy of iodine and glutaraldehyde as fish egg surface disinfectants were assessed in red porgy (Pagrus pagrus) and white sea bream (Diplodus sargus sargus) eggs, two species of interest for Mediterranean aquaculture. Iodine was effective in reducing the bacterial load of the 1-day-old eggs when applied at 50 mg L-1 for 5 min. The same concentration did not cause any significant change in hatching success or survival of the larvae for the first 5 days. Glutaraldehyde failed to reduce the bacterial load of the fish eggs at concentrations that were safe for the eggs (100 mg L-1 for 5 min), as it had a significant effect in preventing hatching of the developed embryo. Disinfecting 0-day-old eggs with iodine resulted in a significant reduction of hatching percentage, while larv...

British Library Electronic Table of Contents (United Kingdom)

Bacterial cellulose produced by the gram-negative bacterium Gluconacetobacter xylinum was found to be an excellent native starting material for preparing shaped ultra-lightweight cellulose aerogels. The procedure comprises thorough washing and sterilization of the aquogel, quantitative solvent exchange and subsequent drying with supercritical carbon dioxide at 40 degreeC and 100 bar. The average density of the obtained dry cellulose aerogels is only about 8 mg cm-3 which is comparable to the most lightweight silica aerogels and distinctly lower than all values for cellulosic aerogels obtained from plant cellulose so far. SEM, ESEM and nitrogen adsorption experiments at 77 K reveal an open-porous network structure that consists of a comparatively high percentage of large mesopores and small...

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The goal of this project is to provide materials engineers, chemical engineers and plant operators with a software tool that will enable them to predict localized corrosion of process equipment including fabricated components as well as base alloys. For design and revamp purposes, the software predicts the occurrence of localized corrosion as a function of environment chemistry and assists the user in selecting the optimum alloy for a given environment. For the operation of existing plants, the software enables the users to predict the remaining life of equipment and help in scheduling maintenance activities. This project combined fundamental understanding of mechanisms of corrosion with focused experimental results to predict the corrosion of advanced, base or fabricated, alloys in real-world environments encountered in the chemical industry. At the heart of this approach is the development of models that predict the fundamental parameters that control the ...

UK PubMed Central (United Kingdom)

The inhibition of DDT [1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane] dehydrochlorinase and glutathione S-aryltransferase by diphenylmethane and triphenylmethane...Full Text Available

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Mineral oil based power transmitting fluids, such as automatic transmission fluids, are disclosed which contain 0.05 to 2.0 weight percent of an ester of a thio-bis alkanol and a C/sub 12/-C/sub 50/ hydrocarbon succinic acid or anhydride, the ester being a multifunctional additive providing the properties of friction modification, corrosion inhibition, anti-wear, oxidation inhibition and extreme pressure properties to the fluids.

UK PubMed Central (United Kingdom)

Pharmacological activation of group II metabotropic glutamate (mGlu2 and mGlu3) receptors inhibits reward-seeking behavior and/or rewarding efficacy induced by drugs (cocaine, nicotine) or natural...Full Text Available

UK PubMed Central (United Kingdom)

ObjectivesThe aim of this study was to comprehensively evaluate the antibacterial activity and MurE inhibition of a set of N-methyl-2-alkenyl-4-quinolones found...Full Text Available

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The effect of WC particle size with the addition of VC as a grain growth inhibitor was investigated during the liquid phase sintering of WC-Co system. With increasing WC particle size at the same VC content, the effect of grain growth inhibition was increased. Also, with increasing the VC content, the grain shape of WC was changed from the faceted shape to the distorted shape, and the step density of the WC grain was increased. (orig.)

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The authors investigated the effect of T-2 toxin on rat liver mitochondrial protein synthesis. Isolated rat liver mitochondria were supplemented with an S-100 supernatant from rat liver and an external ATP-generating system. An in-vitro assay employing cycloheximide, and inhibitor of cytoplasmic protein synthesis, and chloramphenicol, and inhibitor of mitochondrial protein synthesis, to distinguish mitochondrial protein synthesis from the cytoplasmic process. Amino acid incorporation into mitochondria was dependent on the concentration of mitochondria and was inhibited by chloramphenicol. The rate of uptake of tritium leucine into mitochondrial protein was unaffected by the addition of T-2 toxin and was not a rate-limiting step in incorporation. However, 0.02 micrograms/ml of T-2 toxin decreased the rate of protein synthesis inhibition correlated with the amount of T-2 toxin taken up by the mitochondria. While T-2 toxin is known to ...