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81.
M. J. Alcaraz-García M. D. Albaladejo C. Acevedo A. Olea S. Zamora P. Martínez S. Parra 《Journal of physiology and biochemistry》2008,64(2):135-141
Oxygen toxicity is a problem in diving which can have fatal consequences in the water. When divers use closed-circuit oxygen rebreathing apparatus they are taking only oxygen 100% and this hyperoxic exposure increases the generation of reactive oxygen species (ROS) in biological tissues. The objective of the present study is to evaluate the effects of hyperoxia on biomarkers of oxidative stress in closed-circuit oxygen military divers. Fifteen professional divers of Spanish Navy Diving Center participated in a training program which consisted of one-hour immersion at seven metres of depth breathing oxygen 100% with closed-circuit oxygen rebreathing apparatus. The training went on two or three times per week for the first six weeks and once a week for the last six weeks. Serum total antioxidant status (TAS), levels of glutathione peroxidase (GPx), nitrates (NO3 ?) and urinary concentrations of 15-isoprostane F2t were measured. The results show that TAS decreased significantly after 6 weeks (mean 1.38 versus 1.23 mmol/l), with a slight increase at the end (mean 1.31 mmol/l). GPx and F2-isoprostanes were significantly lower after 6 and 12 weeks and NO3 ? was significantly lower after 6 weeks and remained unchanged until the end. In summary, professional divers who use closed-circuit apparatus and therefore breathe oxygen 100%, do not suffer an important oxidative hyperoxia-induced stress, probably due an adaptive process after hyperoxia. The age and good physical form of the subjects studied could probably enhance the adaptive process to hyperoxia. 相似文献
82.
Doumit Camilios Neto Joel Alexandre Meira Elaine Tiburtius Patrício Peralta Zamora Cryshelen Bugay David Alexander Mitchell Nadia Krieger Dr. 《Biotechnology journal》2009,4(5):748-755
Pseudomonas aeruginosa UFPEDA 614 produced a rhamnolipid biosurfactant when grown on sugarcane bagasse impregnated with a solution containing glycerol. Biosurfactant levels reached 40 g of rhamnolipid per kilogram of dry initial substrate after 12 days. On the basis of the volume of liquid used, the biosurfactant levels were similar to those obtained in submerged liquid culture of a medium identical to the impregnating solution. The properties of the biosurfactant were very similar to those obtained with rhamnolipids produced in submerged culture, with a critical micelle concentration of 46.8 mg/L and an emulsification index at 24 h of over 90% against gasoline. The surface properties were maintained after autoclaving of the fermented solids, meaning that it is possible to minimize safety risks by killing the producing organism with a heat treatment of the solids prior to product extraction. The biosurfactant was used in the washing of soils contaminated with gasoline. An aqueous biosurfactant solution was 3.2-fold more efficient than water in leaching organic material from the soil, demonstrating the viability of application of rhamnolipids in the bioremediation of soils contaminated with gasoline. 相似文献
83.
84.
85.
Christopher E. Ramsden Marie Hennebelle Susanne Schuster Gregory S. Keyes Casey D. Johnson Irina A. Kirpich Jeff E. Dahlen Mark S. Horowitz Daisy Zamora Ariel E. Feldstein Craig J. McClain Beverly S. Muhlhausler Maria Makrides Robert A. Gibson Ameer Y. Taha 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2018,1863(10):1206-1213
Background
Linoleic acid (LA) is abundant in modern industrialized diets. Oxidized LA metabolites (OXLAMs) and reactive aldehydes, such as 4-hydroxy-2-nonenal (4-HNE), are present in heated vegetable oils and can be endogenously synthesized following consumption of dietary LA. OXLAMs have been implicated in cerebellar degeneration in chicks; 4-HNE is linked to neurodegenerative conditions in mammals. It unknown whether increasing dietary LA or OXLAMs alters the levels of oxidized fatty acids (oxylipins), precursor fatty acids, or 4-HNE in mammalian brain.Objectives
To determine the effects of increases in dietary OXLAMs and dietary LA, on levels of fatty acids, oxylipins, and 4-HNE in mouse brain tissues.Methods
Mice (n?=?8 per group) were fed one of three controlled diets for 8?weeks: (1) a low LA diet, (2) a high LA diet, or (3) the low LA diet with added OXLAMs. Brain fatty acids, oxylipins, and 4-HNE were quantified in mouse cerebellum and cerebral cortex by gas chromatography-flame ionization detection, liquid chromatography-tandem mass spectrometry, and immunoblot, respectively.Results
Increasing dietary LA significantly increased omega-6 fatty acids, decreased omega-3 fatty acids, and increased OXLAMs in brain. Dietary OXLAMs had minimal effect on oxidized lipids but did decrease both omega-6 and omega-3 fatty acids. Neither dietary LA nor OXLAMs altered 4-HNE levels.Conclusion
Brain fatty acids are modulated by both dietary LA and OXLAMs, while brain OXLAMs are regulated by endogenous synthesis from LA, rather than incorporation of preformed OXLAMs. 相似文献86.
Cristóbal Espinosa Ruiz Lorena Cabrera José Ángel López-Jiménez Salvador Zamora Francisca Pérez-Llamas 《Journal of physiology and biochemistry》2018,74(1):171-177
The infusion tea extracted from the leaves of the plant Camellia sinensis can be used in the prevention of cancer, cardiovascular and neurodegenerative diseases, and aging, while adriamycin (ADR) is an anticancer drug that increases oxidative stress in cells. The present study evaluated the protective effect of the long-term consumption of white tea used at two different doses against the oxidative stress produced by aging and acute oxidation caused ADR treatment. At wearing, rats received distilled water (control), or 0.15 (dose 1) or 0.45 mg (dose 2) of solid tea extract/kilogram body weight in their drink. At 12 months, about half of the rats of each group were injected with a bolus of ADR, and six rats of the control group with an injection of saline solution and sacrificed. The rest of the animals continued in their cages until 24 months of age, when they were sacrificed. Lipid and protein oxidation of liver and brain microsomes was analyzed by measuring hydroperoxide and carbonyl levels. White tea consumption for 12 months at a non-pharmacological dose was seen to reverse the oxidative damage caused by ADR in both liver and brain, while the consumption of white tea for 20 months at a non-pharmacological dose had no effect on carbonyl or hydroperoxides in these tissues. The long-term ingestion of white tea protected tissues from acute oxidative stress but did not affect chronic oxidative agents such aging. 相似文献
87.
INMACULADA Ferriol MARTA Vallino MARINA Ciuffo JARED C. Nigg ERIKA J. Zamora‐Macorra BRYCE W. Falk Massimo Turina 《Molecular Plant Pathology》2018,19(6):1319-1331
Tomato apex necrosis virus (ToANV, species Tomato marchitez virus, genus Torradovirus, family Secoviridae) causes a severe tomato disease in Mexico. One distinctive feature of torradoviruses compared with other members of the family Secoviridae is the presence of an additional open reading frame (ORF) in genomic RNA2 (denominated RNA2‐ORF1), located upstream of ORF2. RNA2‐ORF2 encodes a polyprotein that is processed into a putative movement protein and three capsid proteins (CPs). The RNA2‐ORF1 protein has homologues only amongst other torradoviruses and, so far, no function has been associated with it. We used recombinant and mutant ToANV clones to investigate the role of the RNA2‐ORF1 protein in various aspects of the virus infection cycle. The lack of a functional RNA2‐ORF1 resulted in an inability to systemically infect Nicotiana benthamiana and tomato plants, but both positive‐ and negative‐strand RNA1 and RNA2 accumulated locally in agroinfiltrated areas in N. benthamiana plants, indicating that the RNA2‐ORF1 mutants were replication competent. Furthermore, a mutant with a deletion in RNA2‐ORF1 was competent for virion formation and cell‐to‐cell movement in the cells immediately surrounding the initial infection site. However, immunological detection of the ToANV CPs in the agroinfiltrated areas showed that this mutant was not detected in the sieve elements even if the surrounding parenchymatic cells were ToANV positive, suggesting a role for the RNA2‐ORF1 protein in processes occurring prior to phloem uploading, including efficient spread in inoculated leaves. 相似文献
88.
F. J. Sánchez-Vázquez M. Iigo J. A. Madrid S. Zamora M. Tabata 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(6):409-415
Melatonin is regarded as an internal zeitgeber, involved in the synchronization to light of the daily and seasonal rhythms
of vertebrates. To date, plasma and ocular melatonin in fish have been extensively surveyed almost solely in freshwater species
– with the exception of some migrating species of salmonids. In the present paper, melatonin levels of a marine species (sea
bass, Dicentrarchus labrax L) were examined. In addition, the daily rhythms of the demand-feeding activity of sea bass, a fish species characterized
by a dual phasing capacity (i.e. the ability to switch between diurnal and nocturnal behaviour), were investigated before
sampling. Sea bass, distributed in 12 groups of four fish and kept under constant water temperature and salinity, were exposed
to a 12 h light:12 h dark cycle (200:0 lx, lights on at 0800 hours). After 4 weeks recording, the animals were killed at 0900,
1200, 1400, 1600, 1900, 2100, 2400, 0200, 0400, 0700 and 0900 hours. Actograms of demand-feeding records revealed a nocturnal
feeding behaviour, with some cases of spontaneous inversions in phasing. Melatonin levels in plasma peaked in the middle of
the dark phase, dropping after lights on. Melatonin in the eye, on the contrary, exhibited an inverse profile, with high levels
during daytime and low levels at night. These results suggest that melatonin in the plasma and the eye may act independently
on the flexible circadian system of sea bass.
Accepted: 30 January 1997 相似文献
89.
We examined the phylogenetic relationships among five heterothallic species of Neurospora using restriction fragment polymorphisms derived from cosmid probes and sequence data from the upstream regions of two genes, al-1 and frq. Distance, maximum likelihood, and parsimony trees derived from the data support the hypothesis that strains assigned to N. sitophila, N. discreta, and N. tetrasperma form respective monophyletic groups. Strains assigned to N. intermedia and N. crassa, however, did not form two respective monophyletic groups, consistent with a previous suggestion based on analysis of mitochondrial DNAs that N. crassa and N. intermedia may be incompletely resolved sister taxa. Trees derived from restriction fragments and the al-1 sequence position N. tetrasperma as the sister species of N. sitophila. None of the trees produced by our data supported a previous analysis of sequences in the region of the mating type idiomorph that grouped N. crassa and N. sitophila as sister taxa, as well as N. intermedia and N. tetrasperma as sister taxa. Moreover, sequences from al-1, frq, and the mating-type region produced different trees when analyzed separately. The lack of consensus obtained with different sequences could result from the sorting of ancestral polymorphism during speciation or gene flow across species boundaries, or both. 相似文献
90.
Optimization of performance in collective systems often requires altruism. The emergence and stabilization of altruistic
behaviors are difficult to achieve because the agents incur a cost when behaving altruistically. In this paper, we propose
a biologically inspired strategy to learn stable altruistic behaviors in artificial multi-agent systems, namely reciprocal
altruism. This strategy in conjunction with learning capabilities make altruistic agents cooperate only between themselves,
thus preventing their exploitation by selfish agents, if future benefits are greater than the current cost of altruistic acts.
Our multi-agent system is made up of agents with a behavior-based architecture. Agents learn the most suitable cooperative
strategy for different environments by means of a reinforcement learning algorithm. Each agent receives a reinforcement signal
that only measures its individual performance. Simulation results show how the multi-agent system learns stable altruistic
behaviors, so achieving optimal (or near-to-optimal) performances in unknown and changing environments.
Received: 1 August 1997 / Accepted in revised form: 28 November 1997 相似文献