897 resultados para acid production


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The 3-hydroxy-3methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, or statins, can achieve significant reductions in plasma low-density lipoprotein (LDL)-cholesterol levels. Experimental and clinical evidence now shows that some statins interfere with formation of atherosclerotic lesions independent of their hypolipidemic properties. Vulnerable plaque rupture can result in thrombus formation and artery occlusion; this plaque deterioration is responsible for most acute coronary syndromes, including myocardial infarction (MI), unstable angina, and coronary death, as well as coronary heart diseaseequivalent non-hemorrhagic stroke. Inhibition of HMG-CoA reductase has potential pleiotropic effects other than lipid-lowering, as statins block mevalonic acid production, a precursor to cholesterol and numerous other metabolites. Statins' beneficial effects on clinical events may also thus involve nonlipid-related mechanisms that modify endothelial function, inflammatory responses, plaque stability, and thrombus formation. Aspirin, routinely prescribed to post-MI patients as adjunct therapy, may potentiate statins beneficial effects, as aspirin does not compete metabolically with statins but acts similarly on atherosclerotic lesions. Common functions of both medications include inhibition of platelet activity and aggregation, reduction in atherosclerotic plaque macrophage cell count, and prevention of atherosclerotic vessel endothelial dysfunction. The Cholesterol and Recurrent Events (CARE) trial provides an ideal population in which to examine the combined effects of pravastatin and aspirin. Lipid levels, intermediate outcomes, are examined by pravastatin and aspirin status, and differences between the two pravastatin groups are found. A modified Cox proportional-hazards model with aspirin as a time-dependent covariate was used to determine the effect of aspirin and pravastatin on the clinical cardiovascular composite endpoint of coronary heart disease death, recurrent MI or stroke. Among those assigned to pravastatin, use of aspirin reduced the composite primary endpoint by 35%; this result was similar by gender, race, and diabetic status. Older patients demonstrated a nonsignificant 21% reduction in the primary outcome, whereas the younger had a significant reduction of 43% in the composite primary outcome. Secondary outcomes examined include coronary artery bypass graft (38% reduction), nonsurgical bypass, peripheral vascular disease, and unstable angina. Pravastatin and aspirin in a post-MI population was found to be a beneficial combination that seems to work through lipid and nonlipid, anti-inflammatory mechanisms. ^

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Anthropogenic CO2 is progressively acidifying the ocean, but the responses of harmful algal bloom species that produce toxins that can bioaccumulate remain virtually unknown. The neurotoxin domoic acid is produced by the globally-distributed diatom genus Pseudo-nitzschia. This toxin is responsible for amnesic shellfish poisoning, which can result in illness or death in humans and regularly causes mass mortalities of marine mammals and birds. Domoic acid production by Pseudo-nitzschia cells is known to be regulated by nutrient availability, but potential interactions with increasing seawater CO2 concentrations are poorly understood. Here we present experiments measuring domoic acid production by acclimatized cultures of Pseudo-nitzschia fraudulenta that demonstrate a strong synergism between projected future CO2 levels (765 ppm) and silicate-limited growth, which greatly increases cellular toxicity relative to growth under modern atmospheric (360 ppm) or pre-industrial (200 ppm) CO2 conditions. Cellular Si:C ratios decrease with increasing CO2, in a trend opposite to that seen for domoic acid production. The coastal California upwelling system where this species was isolated currently exhibits rapidly increasing levels of anthropogenic acidification, as well as widespread episodic silicate limitation of diatom growth. Our results suggest that the current ecosystem and human health impacts of toxic Pseudo-nitzschia blooms could be greatly exacerbated by future ocean acidification and 'carbon fertilization' of the coastal ocean.

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Fusarium proliferatum has been reported on garlic in the Northwest USA, Spain and Serbia, causing water-soaked tan-colored lesions on cloves. In this work, Fusarium proliferatum was isolated from 300 symptomatic garlic bulbs. Morphological identification of Fusarium was confirmed using species-specific PCR assays and EF-1α sequencing. Confirmation of pathogenicity was conducted with eighteen isolates. Six randomly selected F. proliferatum isolates from garlic were tested for specific pathogenicity and screened for fusaric acid production. Additionally, pathogenicity of each F. proliferatum isolate was tested on healthy seedlings of onion (Allium cepa), leek (A. porrum), scallions (A. fistulosum), chives (A. schoenoprasum) and garlic (A. sativum). A disease severity index (DSI) was calculated as the mean severity on three plants of each species with four test replicates. Symptoms on onion and garlic plants were observed three weeks after inoculation. All isolates tested produced symptoms on all varieties inoculated. Inoculation of F. proliferatum isolates from diseased garlic onto other Allium species provided new information on host range and pathogenicity. The results demonstrated differences in susceptibility with respect to host species and cultivar. The F. proliferatum isolates tested all produced fusaric acid (FA); correlations between FA production and isolate pathogenicity are discussed. Additionally, all isolates showed the presence of the FUM1 gene suggesting the ability of Spanish isolates to produce fumonisins.

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The aim of this work was to assess the effects of four doses of three commercial fibrolytic enzymes on ruminal fermentation of rice straw, maize stover and Pennisetum purpureum clon Cuba CT115 hay in batch cultures of ruminal micro-organisms from sheep. One enzyme was produced by Penicillium funiculosum (PEN) and two were from Trichoderma longibrachiatum (TL1 and TL2). Each liquid enzyme was diluted 200 (D1), 100 (D2), 50 (D3) and 10 (D4) - fold and applied to each substrate in quadruplicate over time and incubated for 120 h in rumen fluid. The D4 dose of each enzyme increased (P<0.05) the fractional rate of gas production and organic matter effective degradability for all substrates, and TL2 had similar effects when applied at D3. In 9 h incubations, PEN at D4, TL1 at all tested doses, and TL2 at D2, D3 and D4 increased (P<0.05) volatile fatty acid production and dry matter degradability for all substrates. The commercial enzymes tested were effective at increasing in vitro ruminal fermentation of low-quality forages, although effective doses varied with the enzyme.

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The Schizosaccharomyces strains consumed less primary amino nitrogen and produced less urea and more pyruvic acid than other Saccharomyces species. Further, three of the four Schizosaccharomyces strains completed the breakdown of malic acid by day 4 of fermentation. The main negative effect of the use of Schizosaccharomyces was strong acetic acid production. The Schizosaccharomyces strains that produced most pyruvic acid (938 and 936) were associated with better ?wine? colour than the remaining yeasts. The studied Schizosaccharomyces could therefore be of oenological interest.

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Winter oats were grown according to European organic farming regulations in monoculture (oats) and in intercropping with bard vetch (BAV), bitter vetch (BIV) or both legumes (MIX) to evaluate the effects of intercropping on forage yield and nutritive value for ruminants. The experiment was carried out as a randomised complete block design with four replications, and whole forage samples were obtained at two harvest dates (June and July). For both harvest times, all intercrops increased (P < 0.05) forage yield compared with oats, but forage crude protein content was only increased (P < 0.05) for BAV and MIX. Compared with oats, intercropping with BAV increased (P < 0.05) in vitro rate of gas production and total volatile fatty acid production, indicating a higher rate and extent of rumen degradation of BAV forage. In contrast, BIV forage harvested in June had lower (P < 0.05) rate of gas production and total volatile fatty acid production than June oats, but in general no differences in the in vitro rumen fermentation were detected between oats and BIV samples harvested in July. The results indicate that forage yield and quality can be enhanced by intercropping oats with BAV; however, intercropping with BIV increased yield but decreased nutritive value of the forage.

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Papers published chiefly at the University of California between 1913-1924.

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Paracetamol is regarded as a relatively safe drug in the gastro-duodenal region of humans but recent epidemiological investigations have suggested that at high doses there may be an increased risk of ulcers and bleeding. To investigate the possibility that inflammatory conditions and gastric acidity may play a role in potentiating development of gastric mucosal injury from paracetamol in rats (as noted previously with various non-steroidal anti-inflammatory drugs) we studied the gastric irritant effects of paracetamol and some phenolic and non-phenolic analgesics and antipyretics in rats with adjuvant or collagen II induced arthritis or zymosan-induced paw inflammation and given 1.0 ml hydrochloric acid (HCl) 0.1 M and/or an i. p. injection of the cholinomimetic, acetyl-β-methyl choline chloride 5.0 mg/kg. Gastric lesions were determined 2 h after oral administration of 100 or 250 mg/kg paracetamol or at therapeutically effective doses of the phenolic or non-phenolic analgesics/antipyretics. The results showed that gastric mucosal injury occurred with all these agents when given to animals that received all treatments so indicating there is an adverse synergy of these three factors, namely: (i) intrinsic disease; (ii) hyperacidity; and (iii) vagal stimulation for rapidly promoting gastric damage, both in the fundic as well as the antral mucosa, for producing gastric damage by paracetamol, as well as the other agents. Removing one of these three predisposing factors effectively blunts/abolishes expression of this paracetamol-induced gastrotoxity in rats. These three factors, without paracetamol, did not cause significant acute gastropathy.

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Purpose To investigate the prevalence of infected herniated nucleus material in lumbar disc herniations and to determine if patients with an anaerobic infected disc are more likely to develop Modic change (MC) (bone oedema) in the adjacent vertebrae after the disc herniation. MCs (bone oedema) in vertebrae are observed in 6 % of the general population and in 35-40 % of people with low back pain. These changes are strongly associated with low back pain. There are probably a mechanical cause and an infective cause that causes MC. Several studies on nuclear tissue from herniated discs have demonstrated the presence of low virulent anaerobic microorganisms, predominantly Propionibacterium acnes, in 7-53 % of patients. At the time of a herniation these low virulent anaerobic bacteria may enter the disc and give rise to an insidious infection. Local inflammation in the adjacent bone may be a secondary effect due to cytokine and propionic acid production. Methods Patients undergoing primary surgery at a single spinal level for lumbar disc herniation with an MRI-confirmed lumbar disc herniation, where the annular fibres were penetrated by visible nuclear tissue, had the nucleus material removed. Stringent antiseptic sterile protocols were followed. Results Sixty-one patients were included, mean age 46.4 years (SD 9.7), 27 % female. All patients were immunocompetent. No patient had received a previous epidural steroid injection or undergone previous back surgery. In total, microbiological cultures were positive in 28 (46 %) patients. Anaerobic cultures were positive in 26 (43 %) patients, and of these 4 (7 %) had dual microbial infections, containing both one aerobic and one anaerobic culture. No tissue specimens had more than two types of bacteria identified. Two (3 %) cultures only had aerobic bacteria isolated. In the discs with a nucleus with anaerobic bacteria, 80 % developed new MC in the vertebrae adjacent to the previous disc herniation. In contrast, none of those with aerobic bacteria and only 44 % of patients with negative cultures developed new MC. The association between an anaerobic culture and new MCs is highly statistically significant (P = 0.0038), with an odds ratio of 5.60 (95 % CI 1.51-21.95). Conclusion These findings support the theory that the occurrence of MCs Type 1 in the vertebrae adjacent to a previously herniated disc may be due to oedema surrounding an infected disc. The discs infected with anaerobic bacteria were more likely (P<0.0038) to develop MCs in the adjacent vertebrae than those in which no bacteria were found or those in which aerobic bacteria were found. © Springer-Verlag Berlin Heidelberg 2013.

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Mathematical modeling may have different purposes in chemical and biochemical engineering sciences. One of them is to confirm or to reject kinetic models for certain processes, or to evaluate the importance of some transport phenomena on the net chemical or biochemical reaction rate. In the present paper different microbial processes are considered and modeled for evaluation of kinetic constants for batch and continuous processes accomplished by free and immobilized microbial cells. The practical examples are from the field of wastewater treatment and biosynthesis of products, like enzymes, lactic acid, gluconic acid, etc. By the aid of mathematical modeling the kinetics and the type of inhibition are specified for microbial wastewater denitrification and biodegradation of halogenated hydrocarbons. The importance of free and immobilized cells and their separate contribution to the overall microbial process is also evaluated for some fermentation processes: gluconic acid production, dichloroethane biodegradation, lactic acid fermentation and monochloroacetic acid biodegradation.

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Twenty endophytic bacteria were isolated from the meristematic tissues of three varieties of strawberry cultivated in vitro, and further identified, by FAME profile, into the genera Bacillus and Sphingopyxis. The strains were also characterized according to indole acetic acid production, phosphate solubilization and potential for plant growth promotion. Results showed that 15 strains produced high levels of IAA and all 20 showed potential for solubilizing inorganic phosphate. Plant growth promotion evaluated under greenhouse conditions revealed the ability of the strains to enhance the root number, length and dry weight and also the leaf number, petiole length and dry weight of the aerial portion. Seven Bacillus spp. strains promoted root development and one strain of Sphingopyxis sp. promoted the development of plant shoots. The plant growth promotion showed to be correlated to IAA production and phosphate solubilization. The data also suggested that bacterial effects could potentially be harnessed to promote plant growth during seedling acclimatization in strawberry

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In a hospital environment, these bacteria can be spread by insects such as ants, which are characterized by high adaptability to the urban environment. Staphylococcus is a leading cause of hospital infection. In Europe, Latin America, USA and Canada, the group of coagulase negative staphylococci (CoNS) is the second leading cause of these infections, according to SENTRY (antimicrobial surveillance program- EUA). In this study, we investigated the potential of ants (Hymenoptera: Formicidae) as vehicle mechanics of Staphylococcus bacteria in a public hospital, in Natal-RN. The ants were collected, day and night, from June 2007 to may 2008, in the following sectors: hospitals, laundry, kitchen, blood bank. The ants were identified according to the identification key of Bolton, 1997. For the analysis of staphylococci, the ants were incubated in broth Tryptic Soy Broth (TSB) for 24 hours at 35 º C and then incubated on Mannitol Salt Agar. The typical colonies of staphylococci incubated for 24 hours at 35 ° C in Tryptic Soy Agar for the characterization tests (Gram stain, catalase, susceptibility to bacitracin and free coagulase). The identification of CoNS was performed through biochemical tests: susceptibility to novobiocin, growth under anaerobic conditions, presence of urease, the ornithine decarboxylation and acid production from the sugars mannose, maltose, trehalose, mannitol and xylose. The antimicrobial susceptibility examined by disk-diffusion technique. The technique of Polymerase Chain Reaction was used to confirm the presence of mecA gene and the ability to produce biofilm was verified by testing in vitro using polystyrene inert surface, in samples of resistant staphylococci. Among 440 ants, 85 (19.1%) were carrying coagulase-negative staphylococci (CoNS) of the species Staphylococcus saprophyticus (17), Staphylococcus epidermidis (15), Staphylococcus xylosus (13), Staphylococcus hominis hominis (10), Staphylococcus lugdunensis (10), Staphylococcus warneri (6), Staphylococcus cohnii urealyticum (5), Staphylococcus haemolyticus (3), Staphylococcus simulans (3), Staphylococcus cohnii cohnii (2), and Staphylococcus capitis (1). No Staphylococcus aureus was found. Among the isolates, 30.58% showed resistance to erythromycin. Two samples of CoNS (2.35%), obtained from the ant Tapinoma melanocephalum collected in the post-surgical female ward, S. Hominis hominis and S. lugdunensis harbored the mecA gene and were resistant to multiple antibiotics, and the specie S. hominis hominis even showed to be a biofilm producer. This study proves that ants act as carriers of multidrug-resistant coagulase-negative Staphylococci and biofilm producers and points to the risk of the spreading of pathogenic microorganisms by this insect in the hospital environment

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Transgenic plants of Nicotiana tabacum L. homozygous for an RNAi construct designed to silence ornithine decarboxylase (ODC) had significantly lower concentrations of nicotine and nornicotine, but significantly higher concentrations of anatabine, compared with vector-only controls. Silencing of ODC also led to significantly reduced concentrations of polyamines (putrescine, spermidine and spermine), tyramine and phenolamides (caffeoylputrescine and dicaffeoylspermidine) with concomitant increases in concentrations of amino acids ornithine, arginine, aspartate, glutamate and glutamine. Root transcript levels of S-adenosyl methionine decarboxylase, S-adenosyl methionine synthase and spermidine synthase (polyamine synthesis enzymes) were reduced compared with vector controls, whilst transcript levels of arginine decarboxylase (putrescine synthesis), putrescine methyltransferase (nicotine production) and multi-drug and toxic compound extrusion (alkaloid transport) proteins were elevated. In contrast, expression of two other key proteins required for alkaloid synthesis, quinolinic acid phosphoribosyltransferase (nicotinic acid production) and a PIP-family oxidoreductase (nicotinic acid condensation reactions), were diminished in roots of odc-RNAi plants relative to vector-only controls. Transcriptional and biochemical differences associated with polyamine and alkaloid metabolism were exacerbated in odc-RNAi plants in response to different forms of shoot damage. In general, apex removal had a greater effect than leaf wounding alone, with a combination of these injury treatments producing synergistic responses in some cases. Reduced expression of ODC appeared to have negative effects upon plant growth and vigour with some leaves of odc-RNAi lines being brittle and bleached compared with vector-only controls. Together, results of this study demonstrate that ornithine decarboxylase has important roles in facilitating both primary and secondary metabolism in Nicotiana.

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The rhizospheric zone abutting plant roots usually clutches a wealth of microbes. In the recent past, enormous genetic resources have been excavated with potential applications in host plant interaction and ancillary aspects. Two Pseudomonas strains were isolated and identified through 16S rRNA and rpoD sequence analyses as P. fluorescens QAU67 and P. putida QAU90. Initial biochemical characterization and their root-colonizing traits indicated their potential role in plant growth promotion. Such aerobic systems, involved in gluconic acid production and phosphate solubilization, essentially require the pyrroloquinoline quinine (PQQ)- dependent glucose dehydrogenase (GDH) in the genome. The PCR screening and amplification of GDH and PQQ and subsequent induction of mutagenesis characterized their possible role as antioxidants as well as in growth promotion, as probed in vitro in lettuce and in vivo in rice, bean, and tomato plants. The results showed significant differences (p ≤ 0.05) in parameters of plant height, fresh weight, and dry weight, etc., deciphering a clear and in fact complementary role of GDH and PQQ in plant growth promotion. Our study not only provides direct evidence of the in vivo role of GDH and PQQ in host plants but also reveals their functional inadequacy in the event of mutation at either of these loci.