36 research outputs found
Noise-induced instabilities in a stochastic Brusselator
We consider a stochastic version of the so-called Brusselator - a
mathematical model for a two-dimensional chemical reaction network - in which
one of its parameters is assumed to vary randomly. It has been suggested via
numerical explorations that the system exhibits noise-induced synchronization
when time goes to infinity. Complementing this perspective, in this work we
explore some of its finite-time features from a random dynamical systems
perspective. In particular, we focus on the deviations that orbits of
neighboring initial conditions exhibit under the influence of the same noise
realization. For this, we explore its local instabilities via finite-time
Lyapunov exponents. Furthermore, we present the stochastic Brusselator as a
fast-slow system in the case that one of the parameters is much larger than the
other one. In this framework, an apparent mechanism for generating the
stochastic instabilities is revealed, being associated to the transition
between the slow and fast regimes
A singular perturbation analysis for the Brusselator
In this work we study the Brusselator - a prototypical model for chemical
oscillations - under the assumption that the bifurcation parameter is of order
for positive . The dynamics of this mathematical
model exhibits a time scale separation visible via fast and slow regimes along
its unique attracting limit cycle. Noticeably this limit cycle accumulates at
infinity as , so that in polar coordinates ,
and by doing a further change of variable , we analyse the
dynamics near the line at infinity, corresponding to the set . This
object becomes a nonhyperbolic invariant manifold for which we use a
desingularising rescaling, in order to study the closeby dynamics. Further use
of geometric singular perturbation techniques allows us to give a decomposition
of the Brusselator limit cycle in terms of four different fully quantified time
scales
Metabolic Capability of Penicillium oxalicum to Transform High Concentrations of Anti-Inflammatory and Analgesic Drugs
Olicón-Hernández would like to thank Consejo Nacional de Ciencia y Tecnología (CONACyT)
for the postdoc fellowships (231581/454815). E. A. would like to thank the Ministry of Economy and Competitiveness
(MINECO) and European Regional Development Fund (ERDF) funds [RYC-2013-12481] and [CTM- 2017-84332,
MINECO/AEI/FEDER, UE].Non-steroidal anti-inflammatory drugs (NSAIDs) and analgesics are two of the most
employed drug groups around the world due to their use in the treatment of edema and pain.
However, they also present an ecological challenge because they are considered as potential water
pollutants. In this work, the biodegradation of four NSAIDs (diclofenac, ibuprofen, naproxen and
ketoprofen) and one analgesic (acetaminophen) at 50 µM (initial concentration) by Penicillium oxalicum,
at both flask and bioreactor bench scales, was evaluated. An important co-metabolic mechanism
as part of the global bioremediation process for the elimination of these drugs was observed, as in
some cases it was necessary to supplement glucose to achieve a 100% removal rate: both individually
and as a complex mixture. Identical behavior in the implementation of a fluidized bench-scale batch
bioreactor, inoculated with pellets of this fungus and the complex mix of the drugs, was observed.
The role of the cytochrome P450 enzymes (CYP) in the biodegradation of the drugs mix were
evidenced by the observation of hydroxylated by-products. The results on the reduction of toxicity
(micro and phyto) were not conclusive; however, a reduction in phytotoxicity was detected.MINECO-ERDF funds [MINECO/AEI/ERDF, UE]
RYC-2013-12481
CTM-2017-84332Consejo Nacional de Ciencia y Tecnologia (CONACyT)
231581/45481
Pharmaceutical Pollution in Aquatic Environments: A Concise Review of Environmental Impacts and Bioremediation Systems
The presence of emerging contaminants in the environment, such as pharmaceuticals, is a growing global concern. The excessive use of medication globally, together with the recalcitrance of pharmaceuticals in traditional wastewater treatment systems, has caused these compounds to present a severe environmental problem. In recent years, the increase in their availability, access and use of drugs has caused concentrations in water bodies to rise substantially. Considered as emerging contaminants, pharmaceuticals represent a challenge in the field of environmental remediation; therefore, alternative add-on systems for traditional wastewater treatment plants are continuously being developed to mitigate their impact and reduce their effects on the environment and human health. In this review, we describe the current status and impact of pharmaceutical compounds as emerging contaminants, focusing on their presence in water bodies, and analyzing the development of bioremediation systems, especially mycoremediation, for the removal of these pharmaceutical compounds with a special focus on fungal technologies.Peer reviewe
Biodegradation and Absorption Technology for Hydrocarbon-Polluted Water Treatment
Wastewaters polluted with hydrocarbons are an environmental problem that has a significant
impact on the natural ecosystem and on human health. Thus, the aim of this research was to develop
a bioreactor sorbent technology for treating these polluted waters. A lab-scale plant composed
of three 1-L bioreactors with different sorbent materials inside (meltblown polypropylene and
granulated cork) was built. Wastewater to be treated was recirculated through each bioreactor for
7 days. Results showed that hydrocarbon retention rates in the three bioreactors ranged between
92.6% and 94.5% of total petroleum hydrocarbons (TPHs) and that after one simple recirculation
cycle, no hydrocarbon fractions were detected by gas chromatography/Mass Spectrometry (GC/MS)
in the effluent wastewater. In addition, after the wastewater treatment, the sorbent materials
were extracted from the bioreactors and deposited in vessels to study the biodegradation of the
retained hydrocarbons by the wastewater indigenous microbiota adhered to sorbents during the
wastewater treatment. A TPH removal of 41.2% was detected after one month of Pad SentecTM carrier
treatment. Further, the shifts detected in the percentages of some hydrocarbon fractions suggested
that biodegradation is at least partially involved in the hydrocarbon removal process. These results
proved the efficiency of this technology for the treatment of these hydrocarbon-polluted-waters.This research was funded by Compañía Logística de Hidrocarburos S.A. and Dario Rafael Olicón-Hernández
was funding by Consejo Nacional de Ciencia y Tecnología of Mexico (CONACyT) for the postdoc fellowships
(231581/454815
Overview on the Biochemical Potential of Filamentous Fungi to Degrade Pharmaceutical Compounds
Pharmaceuticals represent an immense business with increased demand due to intensive livestock raising and an aging human population, which guarantee the quality of human life and well-being. However, the development of removal technologies for these compounds is not keeping pace with the swift increase in their use. Pharmaceuticals constitute a potential risk group of multiclass chemicals of increasing concern since they are extremely frequent in all environments and have started to exhibit negative effects on micro- and macro-fauna as well as on human health. In this context, fungi are known to be extremely diverse and poorly studied microorganisms despite being well suited for bioremediation processes, taking into account their metabolic and physiological characteristics for the transformation of even highly toxic xenobiotic compounds. Increasing studies indicate that fungi can transform many structures of pharmaceutical compounds, including anti-inflammatories, β-blockers, and antibiotics. This is possible due to different mechanisms in combination with the extracellular and intracellular enzymes, which have broad of biotechnological applications. Thus, fungi and their enzymes could represent a promising tool to deal with this environmental problem. Here, we review the studies performed on pharmaceutical compounds biodegradation by the great diversity of these eukaryotes. We examine the state of the art of the current application of the Basidiomycota division, best known in this field, as well as the assembly of novel biodegradation pathways within the Ascomycota division and the Mucoromycotina subdivision from the standpoint of shared enzymatic systems, particularly for the cytochrome P450 superfamily of enzymes, which appear to be the key enzymes in these catabolic processes. Finally, we discuss the latest advances in the field of genetic engineering for their further application
Monitoreo de la actividad enzimática de las lipasas intracelulares de Ustilago maydis expresada durante el crecimiento en limitación de nitrógeno y su correlación en reacciones lipolíticas
Under nitrogen starvation, Ustilago maydis forms lipid droplets (LDs). Although the dynamics of these organelles are known in the literature, the identity of the lipases implicated in their degradation is unknown. We determined lipase activity and identified the intracellular lipases expressed during growth under nitrogen starvation and YPD media by zymograms. The results showed that cytosolic extracts exhibited higher lipase activity when cells were grown in YPD. Under nitrogen starvation, lipase activity was not detected after 24 h of culture, resulting in lipid accumulation in LDs. This suggests that these lipases could be implicated in LD degradation. In the zymogram, two bands, one of 25 and the other of 37 kDa, presented lipase activity. The YPD extracts showed lipase activity in olive and almond oils, which contain triacylglycerols with mono and polyunsaturated fatty acids. This is the first report about U. maydis cytosolic lipases involved in LD degradation.En ausencia de nitrógeno, Ustilago maydis forma cuerpos lipídicos (LDs). Aunque se conoce la dinámica de estos organelos, se desconoce la identidad de las lipasas implicadas en su degradación. En este estudio se determinó la actividad de lipasa, y se identificaron las lipasas intracelulares expresadas durante el crecimiento sin nitrógeno y en YPD mediante zimogramas. Los extractos citosólicos de células en YPD exhibieron mayor actividad de lipasa. En medio sin nitrógeno no se detectó actividad de lipasa después de 24 h de cultivo, presentándose acumulación de lípidos en los LDs. Esto sugiere que estas lipasas podrían implicarse en la degradación de los LDs. En el zimograma bandas de 25 y 37 kDa, presentaron actividad de lipasa. Los extractos de células cultivadas en YPD hidrolizaron triacilgliceroles compuestos de ácidos grasos mono y poliinsaturados. Este es el primer reporte sobre lipasas citosólicas de U. maydis implicadas en la degradación de LDs
Papel de la 5-hidroxitriptamina en el núcleo reticular del tálamo sobre la respuesta de ansiedad de la rata
Tesis (Químico Farmacéutico Industrial), Instituto Politécnico Nacional, ENCB, 2016, 1 archivo PDF, (45 páginas).tesis.ipn.m