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41.
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Summary The growth kinetics in batch culture of 6 strains, potentially useful as starter cultures for ewe's cheese-making, has been analysed. Under the experimental conditions used a high conversion of carbohydrates into lactic acid was achieved. The production of lactic acid can be used as an indirect biomass measurement. Two mathematical models (Logistic and Gompertz's) have been used to describe the growth of these strains in batch culture. Both models fit well to the experimental results, however the Gompertz's model describes slightly better the growth kinetics. 相似文献
43.
V M Fernandez M L Rua P Reyes R Cammack E C Hatchikian 《European journal of biochemistry》1989,185(2):449-454
The effect of several transition metals on the activity of Desulfovibrio gigas hydrogenase has been studied. Co(II) and Ni(II) at a concentration of 1 mM did not modify the activity of the enzyme; nor did they affect the pattern of activation/deactivation. Cu(II) inhibited the active hydrogenase, prepared by treatment with hydrogen, but had little effect on the 'unready' enzyme unless a reductant such as ascorbate was present, in which case inactivation took place either in air or under argon. Hg(II) also inactivated the enzyme irreversible in the 'unready' state without the requirement for reductants. The reaction of H2 uptake with methyl viologen was much more sensitive to inhibition than the H2/tritium exchange activity. EPR spectra of this preparation showed that the rates of decline were [3Fe-4S] signal greater than H2-uptake activity greater than Ni-A signal. Similar results were obtained when the protein was treated with Hg(II). The results demonstrate that the [3Fe-4S] cluster is not essential for H2-uptake activity with methyl viologen, but the integrity of [4Fe-4S] clusters is probably necessary to catalyze the reduction of methyl viologen with hydrogen. D. gigas hydrogenase was found to be highly resistant to digestion by proteases. 相似文献
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Simone de Sales Costa Moreira Carboni Adilha Misson Rua Micheletti Nanci Mendes Pinheiro Nathália Alves Rodrigues Lima Camilla Christian Gomes Moura Fabrizio Antonio Gomide Cardoso Virgínia Oliveira Crema 《Tissue & cell》2014,46(6):527-534
The pleomorphic adenoma of the parotid (PA) is characterized by the high tissues diversity. Rho GTPases participate in signal transduction pathways that regulate several biological processes, including cell differentiation. A quantitative analysis of RhoA and RhoB GTPases immunoexpression was performed in healthy parotids and in 23 PA cases, predominantly epithelial (PE) or mesenchymal (PM), followed by Student's t test. In PE cases, RhoA immunoexpression was higher in sheets and trabeculae (p < 0.05), whereas RhoB only in sheets (p < 0.05). In normal parotids, RhoA and RhoB were not detected in acinar cells. Ducts have expressed RhoA and RhoB in normal parotids and PA. RhoB was detected in myxoid and chondromyxoid cells. Normal parotids do not express RhoA and RhoB proteins in acinar cells, indicating a lack of function in secretory cells. Despite RhoA and RhoB GTPases are different in their biological roles, no significant difference in immunoexpression of the RhoA and RhoB GTPases in epithelial and mesenchymal structures of PA. 相似文献
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Frank H. Hezemans Noham Wolpe Claire OCallaghan Rong Ye Catarina Rua P. Simon Jones Alexander G. Murley Negin Holland Ralf Regenthal Kamen A. Tsvetanov Roger A. Barker Caroline H. Williams-Gray Trevor W. Robbins Luca Passamonti James B. Rowe 《PLoS computational biology》2022,18(5)
Apathy is a debilitating feature of many neuropsychiatric diseases, that is typically described as a reduction of goal-directed behaviour. Despite its prevalence and prognostic importance, the mechanisms underlying apathy remain controversial. Degeneration of the locus coeruleus-noradrenaline system is known to contribute to motivational deficits, including apathy. In healthy people, noradrenaline has been implicated in signalling the uncertainty of expectations about the environment. We proposed that noradrenergic deficits contribute to apathy by modulating the relative weighting of prior beliefs about action outcomes. We tested this hypothesis in the clinical context of Parkinson’s disease, given its associations with apathy and noradrenergic dysfunction. Participants with mild-to-moderate Parkinson’s disease (N = 17) completed a randomised double-blind, placebo-controlled, crossover study with 40 mg of the noradrenaline reuptake inhibitor atomoxetine. Prior weighting was inferred from psychophysical analysis of performance in an effort-based visuomotor task, and was confirmed as negatively correlated with apathy. Locus coeruleus integrity was assessed in vivo using magnetisation transfer imaging at ultra-high field 7T. The effect of atomoxetine depended on locus coeruleus integrity: participants with a more degenerate locus coeruleus showed a greater increase in prior weighting on atomoxetine versus placebo. The results indicate a contribution of the noradrenergic system to apathy and potential benefit from noradrenergic treatment of people with Parkinson’s disease, subject to stratification according to locus coeruleus integrity. More broadly, these results reconcile emerging predictive processing accounts of the role of noradrenaline in goal-directed behaviour with the clinical symptom of apathy and its potential pharmacological treatment. 相似文献
48.
The Brazilian genus Diplusodon is the second largest genus within Lythraceae. Their 85 species occupy diverse habitats within the ‘cerrado’ vegetation, and range from shrubs and treelets to dwarf, xylopodium-bearing subshrubs. A comparative-morphological survey of their inflorescence structures using Trollian typology is here presented, as well as some evolutionary considerations drawn from mapping inflorescence characters onto a preliminary phylogeny. The inflorescences of Diplusodon are mostly polytelic, ranging from single racemes to more or less complex double-, triple-, and multiple-racemes. Frondose, compound racemes are plesiomorphic within the genus. Nevertheless, an array of derived features has been found among their species, including production of lateral cymes, proliferation of the main axis, diverse patterns of internode elongation, reduction of subtending leaves to bracts, development of accessory branches, paedomorphic flowering, and, in three species, reversion to monotely. 相似文献
49.
Mutagenic potentials of fumonisin contaminated corn following ammonia decontamination procedure 总被引:4,自引:1,他引:4
Douglas L. Park Sam M. Rua Jr. Chester J. Mirocha El -Sayed A. M. Abd-Alla Cong Ying Weng 《Mycopathologia》1992,117(1-2):105-108
Naturally contaminated corn implicated in an outbreak of equine leukoencephalomalacia (ELEM) in southeastern Arizona was analyzed for mutagenic potential using the Salmonella/microsome mutagenicity assay before and after treatment with the ammonia procedure. Crude acetonitrile: water (1+1) extracts of high-pressure/ambient temperature (HP/AT) ammonia decontaminated, HP/AT plus low pressure/high temperature (LP/HT), and non-ammoniated fumonisin contaminated corn were tested for mutagenic potentials. Relatively pure (approx. 90%) fumonisin B1 standard was also tested for comparison purposes. The results of this experiment indicate that there was no mutagenic potential for the fumonisin B1 standard at the concentrations tested (100 g/plate). Also, neither the naturally-contaminated corn nor the ammonia decontaminated samples elicited a positive mutagenic response. Fumonisin B1 levels, as determined by HPLC methods, were reduced by an average of 79% via the ammonia decontamination process. It is encouraging to note that, while further work is necessary to increase the efficacy of the ammonia process to reduce fumonisin levels, the ammonia process did reduce fumonisin levels and no mutagenic potentials were apparent in the treated corn.Abbreviations HP/AT
high pressure/ambient temperature
- LP/HT
low pressure/high temperature
- ELEM
equine leukoencephalomalacia
- FB1
fumonisin B1
- FB2
fumonisin B2 相似文献
50.
Ednildes de Almeida Olympio Rua Marcella Leite Porto Jean Pierre Louzada Ramos Breno Valentim Nogueira Silvana dos Santos Meyrelles Elisardo Corral Vasquez Thiago de Melo Costa Pereira 《Journal of biomedical science》2014,21(1)