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151.
152.
Guadalupe Piñar Concepcion Jimenez-Lopez Katja Sterflinger Jörg Ettenauer Fadwa Jroundi Antonia Fernandez-Vivas Maria Teresa Gonzalez-Muñoz 《Microbial ecology》2010,60(1):15-28
In this study, we investigated under laboratory conditions the bacterial communities inhabiting quarry and decayed ornamental
carbonate stones before and after the application of a Myxococcus xanthus-inoculated culture medium used for consolidation of the stones. The dynamics of the community structure and the prevalence
of the inoculated bacterium, M. xanthus, were monitored during the time course of the consolidation treatment (30 days). For this purpose, we selected a molecular
strategy combining fingerprinting by denaturing gradient gel electrophoresis (DGGE) with the screening of eubacterial 16S
rDNA clone libraries by DGGE and sequencing. Quantification of the inoculated strain was performed by quantitative real-time
PCR (qPCR) using M. xanthus-specific primers designed in this work. Results derived from DGGE and sequencing analysis showed that, irrespective of the
origin of the stone, the same carbonatogenic microorganisms were activated by the application of a M. xanthus culture. Those microorganisms were Pseudomonas sp., Bacillus sp., and Brevibacillus sp. The monitoring of M. xanthus in the culture media of treated stones during the time course experiment showed disparate results depending on the applied
technique. By culture-dependent methods, the detection of this bacterium was only possible in the first day of the treatment,
showing the limitation of these conventional techniques. By PCR-DGGE analysis, M. xanthus was detected during the first 3–6 days of the experiment. At this time, the population of this bacterium in the culture media
varied between 108–106 cells ml−1, as showed by qPCR analyses. Thereafter, DGGE analyses showed to be not suitable for the detection of M. xanthus in a mixed culture. Nevertheless, qPCR analysis using specific primers for M. xanthus showed to be a more sensitive technique for the detection of this bacterium, revealing a population of 104 cells ml−1 in the culture media of both treated stones at the end of the consolidation treatment. The molecular strategy used in this
study is proposed as an effective monitoring system to evaluate the impact of the application of a bacterially induced carbonate
mineralization as restoration/conservation treatment for ornamental stones. 相似文献
153.
Maria Teresa Rodriguez-Estrada Guadalupe Garcia-Llatas María Jesús Lagarda 《Biochemical and biophysical research communications》2014
Cholesterol can undergo oxidation through enzymatic or chemical mechanisms, generating a wide range of oxidation products (COPs) with adverse biological effects. COPs are characterized by different functional groups and are produced in different ratios or amounts, depending on the treatment and storage conditions. To follow the cholesterol oxidation process, 7-ketocholesterol (7-KC) has been often used as an oxidation marker in both model and food systems, since it is easily formed and is one of the most representative ring COPs. However, 7-KC does not always rise with increasing time/temperature conditions, especially in complex systems and high-protein or extensively processed foods. The following review provides a critical picture of the utilization of 7-KC as a cholesterol oxidation marker in model and food systems, focusing on the possible causes and effects of the different behaviours and trends, as well as on the advantages and disadvantages of using 7-KC when the extent of cholesterol oxidation is to be assessed. 相似文献
154.
Diana C. Castro-Rodrguez Luis A. Reyes-Castro Claudia C. Vega Guadalupe L. Rodrguez-Gonzlez Jorge Yez-Fernndez Elena Zambrano 《Probiotics and antimicrobial proteins》2020,12(2):505-516
High-fat diet (HFD) consumption induces obesity and increases blood glucose, insulin resistance, and metabolic disorders. Recent studies suggest that probi 相似文献
155.
Summary Resting-cell studies in Penicillium chrysogenum have indicated that penicillin formation is inhibited by glutamine concentrations higher than 1 mM. Total inhibition was obtained with 10 mM glutamine. This action was neither reverted by the amino acid precursors of the antibiotic moiety nor glutamin affected the in vitro activity of the first enzyme of the penicillin formation pathway. The inhibition was prevented by 1 mM glutathione by mechanisms not related to limitation in the glutamine incorporation nor connected with degradation of the tripeptide. 相似文献
156.
157.
Blanca M. Santoyo Carlos Gonzlez‐Romero Daniel Zrate‐Zrate R. Israel Hernndez‐Benitez Vanessa Pelayo Edson Barrera Carlos H. Escalante Ayde Fuentes‐Benites Guadalupe Martínez‐Morales Julio Lpez Miguel A. Vzquez Francisco Delgado Hugo A. Jimnez‐Vzquez Joaquín Tamariz 《Chirality》2019,31(9):719-749
Enantiopure 3‐((R)‐ and 3‐((S)‐1‐phenylethyl)‐4‐oxazoline‐2‐ones were evaluated as chiral building blocks for the divergent construction of heterocycles with stereogenic quaternary centers. The N‐(R)‐ or N‐(S)‐1‐phenylethyl group of these compounds proved to be an efficient chiral auxiliary for the asymmetric induction of the 4‐ and 5‐positions of the 4‐oxazolin‐2‐one ring through thermal and MW‐promoted nucleophilic conjugated addition to Michael acceptors and alkyl halides. The resulting adducts were transformed via a cascade process into fused six‐membered carbo‐ and heterocycles. The structure of the reaction products depended on the electrophiles and reaction conditions used. Alternative isomeric 4‐methylene‐2‐oxazolidinones served as chiral precursors for a versatile and divergent approach to highly substituted cyclic carbamates. DFT quantum calculations showed that the formation of bicyclic pyranyl compounds was generated by a diastereoselective concerted hetero‐Diels‐Alder cycloaddition. 相似文献
158.
Philipp Gunz Amanda K. Tilot Katharina Wittfeld Alexander Teumer Chin Yang Shapland Theo G.M. van Erp Michael Dannemann Benjamin Vernot Simon Neubauer Tulio Guadalupe Guillén Fernández Han G. Brunner Wolfgang Enard James Fallon Norbert Hosten Uwe Völker Antonio Profico Fabio Di Vincenzo Simon E. Fisher 《Current biology : CB》2019,29(5):895
159.
Yahara GA Javier MA Tulio MJ Javier GR Guadalupe AU 《Bioprocess and biosystems engineering》2007,30(6):389-395
Glucose utilization by Brettanomyces bruxellensis at different acetic acid concentrations under aerobic and anaerobic conditions was investigated. The presence of the organic
acid disturbs the growth and fermentative activity of the yeast when its concentration exceeds 2 g l−1. A mathematical model is proposed for the kinetic behavior analysis of yeast growing in batch culture. A Matlab algorithm
was used for estimation of model parameters, whose confidence intervals were also calculated at a 0.95 probability level using
a t-Student distribution for f degrees of freedom. The model successfully simulated the batch kinetics observed at different concentrations of acetic acid
under both oxygen conditions. 相似文献
160.
Restoring montane cloud forest: establishment of three Fagaceae species in the old fields of central Veracruz,Mexico 下载免费PDF全文
Miguel‐Angel Muñiz‐Castro Guadalupe Williams‐Linera Julieta Benítez‐Malvido 《Restoration Ecology》2015,23(1):26-33
Tropical montane cloud forest is rapidly disappearing and our knowledge of how to restore this system is limited. In a cloud forest of central Veracruz, Mexico, we studied seedling survival, growth, and causes of mortality (microenvironment and herbivory) of three native tree species, Fagus grandifolia, Quercus germana, and Q. xalapensis, transplanted into abandoned pastures (<1 year old) and secondary forests (9–17 years old). Microenvironment differed between the two habitats, temperature and photosynthetically active radiation were higher, and humidity was lower in the abandoned pastures than in the secondary forests. Seedling survival was greater in secondary forests than in pastures: F. grandifolia, 94 and 64%; Q. germana, 88 and 68%; and Q. xalapensis, 61 and 57%, respectively. The cause of mortality differed between habitats, with gophers (24.2% mortality) and mice (4.8%) killing the most seedlings in pastures, and damping‐off (16%) was the most important cause in secondary forests. The relative growth rate in height and basal area was significantly higher in abandoned pastures than in secondary forests; Q. xalapensis had the highest growth rate, followed by Q. germana and F. grandifolia. The environmental conditions in this mountainous cloud forest region seem less stressful to planted seedlings than the conditions of other lowland systems, as frequent clouds favor their establishment even in open sites. We conclude that Fagaceae species can successfully establish in abandoned pastures in mesic environments. Thus, the species studied can be used to speed cloud forest regeneration in the same area at different successional stages. 相似文献