The solution space of metabolic networks: producibility, robustness and fluctuations

Flux analysis is a class of constraint-based approaches to the study of biochemical reaction networks: they are based on determining the reaction flux configurations compatible with given stoichiometric and thermodynamic constraints. One of its main areas of application is the study of cellular metabolic networks. We briefly and selectively review the main approaches to this problem and then, building on recent work, we provide a characterization of the productive capabilities of the metabolic network of the bacterium E.coli in a specified growth medium in terms of the producible biochemical species. While a robust and physiologically meaningful production profile clearly emerges (including biomass components, biomass products, waste etc.), the underlying constraints still allow for significant fluctuations even in key metabolites like ATP and, as a consequence, apparently lay the ground for very different growth scenarios.Comment: 10 pages, prepared for the Proceedings of the International Workshop on Statistical-Mechanical Informatics, March 7-10, 2010, Kyoto, Japa

Towards Optimal Energy-Water Supply System Operation for Agricultural and Metropolitan Ecosystems

The energy-water demands of metropolitan regions and agricultural ecosystems are ever-increasing. To tackle this challenge efficiently and sustainably, the interdependence of these interconnected resources has to be considered. In this work, we present a holistic decision-making framework which takes into account simultaneously a water and energy supply system with the capability of satisfying metropolitan and agricultural resource demands. The framework features: (i) a generic large-scale planning and scheduling optimization model to minimize the annualized cost of the design and operation of the energy-water supply system, (ii) a mixed-integer linear optimization formulation, which relies on the development of surrogate models based on feedforward artificial neural networks and first-order Taylor expansions, and (iii) constraints for land and water utilization enabling multi-objective optimization. The framework provides the operational profiles of all energy-water system elements over a given time horizon, which uncover potential synergies between the essential food, energy, and water resource supply systems.Comment: Part of the Foundations of Computer-Aided Process Operations and Chemical Process Control (FOCAPO/CPC) 2023 Proceeding

Three years field trials to assess the effect of kaolin made particles and copper on olive-fruit fly (B.oleae Gmelin) infestations in Sicily

In most countries of Mediterranean Basin, Bactrocera oleae (Gmel), the olive fruit fly, is the key pest insect on olives. In Sicily this pest causes losses of fruits and a poor quality olive oil. Many researchers have recently carried out some field studies which were based on the use of kaolin and copper against the olive-fruit fly. In the last years these products have been effective several times in reducing olive fly infestation. Kaolin had, also, some important effect in reducing heat-stress in fruit crops and olive-trees. The aim of the present study was to assess the effect of kaolin and copper treatment on olive infestations in Sicily and to evaluate chemical and sensory parameters of oils extracted. For this reason, within 2003-2005, the IX Servizio of Assessorato Regionale Agricoltura e Foreste, selected some olive groves where to carry out trials with kaolin and copper and to realize information and divulgation activities

Efecto de un nuevo xanthanólido sesquiterpeno sobre la activación de mastocitos inducida por neurópeptidos pro-inflamatorios

Los mastocitos son células del tejido conectivo que participan en la génesis y modulación de las respuestas inflamatorias celulares. En trabajos previos hemos demostrado que xanthatina (xanthanólido sesquiterpeno aislado de Xanthium cavanillesii Schouw) inhibe la activación de mastocitos inducida por secretagogos experimentales. Sin embargo, se desconoce su efecto sobre la activación de mastocitos inducida por estímulos fisiopatológicos. Estos estímulos incluyen, entre otros, los neuropéptidos pro-inflamatorios sustancia P y neurotensina, responsables de una de las principales vías de inflamación neurogénica. El objetivo del presente trabajo fue estudiar el efecto de xanthatina sobre la activación de mastocitos inducida por sustancia P y neurotensina. Mastocitos peritoneales de rata se incubaron con: 1) PBS (basal); 2) sustancia P (100 Fm); 3) neurotensina (50 Fm); 4) xanthatina (8-320 Fm)+sustancia P; 5) xanthatina (8-320 Fm)+neurotensina. La viabilidad de los mastocitos se evaluó con azul tripán. En las soluciones de incubación se cuantificó serotonina liberada (marcador de activación). En las células se cuantificó serotonina remanente (no liberada) y se analizó la morfología celular por microscopía óptica y electrónica de transmisión. Tratamiento estadístico: ANOVA-1 y Tukey-Kramer. La incubación de mastocitos con xanthatina inhibió (P<0,01), en forma dosisdependiente, la liberación de serotonina inducida por sustancia P y neurotensina, sin modificar la viabilidad celular. Los mastocitos tratados con neuropéptidos mostraron características morfológicas de degranulación, mientras que la morfología de los mastocitos tratados con xanthatina+neuropéptido fue semejante a los basales. En conclusión, xanthatina inhibe la activación de mastocitos inducida por sustancia P y por neurotensina. Este sesquiterpeno podría representar una nueva alternativa en el tratamiento de las inflamaciones neurogénicas.The present study was designed to examine the effects of a novel natural xanthanolide with anti-ulcer and anti-inflammatory properties (xanthatin) on mast cell activation induced by pro-inflammatory peptides, such as substance P and neurotensin. Peritoneal mast cells from male adult were purified in Percoll, preincubated in the presence of xanthatin and then challenged with the mast cell activators substance P (100 Fm) or neurotensin (50 Fm). Concentration-response studies of mast cell serotonin release evoked by pro-inflammatory neuropeptides, evaluation of mast cell viability and morphology by light and electron microscopy, and drug stability analysis by thin layer chromatography (TLC) were performed. Serotonin release studies, carried out together with morphological studies, showed the effectiveness of xanthatin to stabilize mast cells. The present study provides the first strong evidence in favour of the hypothesis that xanthatin inhibits substance P- and neurotensin-induced serotonin release from peritoneal mast cells, acting thus as a mast cell stabilizer. Our findings may provide an insight into the design of novel pharmacological agents which may be used to regulate the mast cell response in neurogenic inflammation.Fil: Vargas, P.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histologia y Embriología Mendoza. "Dr. Mario H. Burgos"Fil: Martino, E.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Área de Anatomía NormalFil: Fogal, T.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histologia y Embriología Mendoza. "Dr. Mario H. Burgos"Fil: Tonn, C.. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Química.Fil: Penissi, A.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histologia y Embriología Mendoza. "Dr. Mario H. Burgos

Typical properties of optimal growth in the Von Neumann expanding model for large random economies

We calculate the optimal solutions of the fully heterogeneous Von Neumann expansion problem with $N$ processes and $P$ goods in the limit $N\to\infty$. This model provides an elementary description of the growth of a production economy in the long run. The system turns from a contracting to an expanding phase as $N$ increases beyond $P$. The solution is characterized by a universal behavior, independent of the parameters of the disorder statistics. Associating technological innovation to an increase of $N$, we find that while such an increase has a large positive impact on long term growth when $N\ll P$, its effect on technologically advanced economies ($N\gg P$) is very weak.Comment: 8 pages, 1 figur

Zinc ions alter morphology and chitin deposition in an ericoid fungus

A sterile mycelium PS IV, an ascomycete capable of establishing ericoid mycorrhizas, was used to investigate how zinc ions affect the cellular mechanisms of fungal growth. Asignificant reduction of the fungal biomass was observed in the presence of millimolar zinc concentrations; this mirrored conspicuous changes in hyphal morphology which led to apical swellings and increased branching in the subapical parts. Specific probes for fluorescence and electron microscopy localised chitin, the main cell wall polysaccharide, on the inner part of the fungal wall and on septa in control specimens. In Zn-treated mycelium, hyphal walls were thicker and a more intense chitin labelling was detected on the transverse walls. Aquantitative assay showed a significant increase in the amount of chitin in metal- treated hyphae

Hubbard ladders in a magnetic field

The behavior of a two leg Hubbard ladder in the presence of a magnetic field is studied by means of Abelian bosonization. We predict the appearance of a new (doping dependent) plateau in the magnetization curve of a doped 2-leg spin ladder in a wide range of couplings. We also discuss the extension to N-leg Hubbard ladders

Exact results for one-dimensional disordered bosons with strong repulsion

We study one-dimensional incommensurate bosons with strong repulsive interactions and weak disorder. In analogy to the clean Tonks-Girardeau gas, a Bose-Fermi mapping expresses this problem in terms of disordered free fermions. Thereby many known results apply, in particular for the density-density correlations, the distribution function of the local density of states, and the complete spectral statistics. We also analyze the bosonic momentum distribution, and comment on the experimental observability of these predictions in ultracold atomic gases.Comment: 5 pages, 2 figures, published versio

Reliability of miRNA Analysis from Fixed and Paraffin-Embedded Tissues

In clinical practice, patients\u2019 tissues are fixed and paraffin-embedded in order to enable histological diagnosis. Nowadays, those tissues are also used for molecular characterization. Formalin is the most used fixative worldwide, and Bouin\u2019s solution in some worldwide institutions. Among molecular targets, micro RNAs (miRNAs), the single-stranded non-coding RNAs comprised of 18 to 24 nucleotides, have been demonstrated to be resistant to fixation and paraffin-embedding processes, with consequent possible application in clinical practice. In the present study, let-7e-5p, miR-423-3p, miR-92a-1-5p, miR-30d-5p, miR-155-5p, miR-200a-3p, and miR-429 were investigated in formalin and matched Bouin\u2019s solution-fixed tissues of high grade serous ovarian cancers by means of real-time and droplet digital PCR (ddPCR). Micro RNAs were detectable and analyzable in both formalin- and Bouin\u2019s-fixed specimens, but on average, higher Ct values and lower copies/\u3bcL were found in Bouin\u2019s-fixed samples. Data from formalin-fixed samples correlated significantly for most targets with Bouin\u2019s ones, except for let-7e-5p and miR-155-5p. This study shows that miRNAs are analyzable in both formalin- and Bouin\u2019s-fixed specimens, with the possibility, after proper data normalization, to compare miRNA-based data from formalin-fixed samples to those of Bouin\u2019s-fixed ones