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Closed and open Metabolic Cycles: Transition Time

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Journal of Biomedical Science and Engineering 2016年第2期9卷 127-140页

作者： Antonio Sillero v.ctor García-Herrero Departamento de Bioquímica Facultad de Medicina Instituto de Investigaciones Biomédicas Alberto Sols UAM/CSIC Madrid Spain

A metabolic cycle can be viewed as a central core and its branches. The central core is here firstly considered as a pre-closed metabolic cycle (CMC), with a unique first substrate, but with no input or output of other components. By contrast, the metabolic cycles in nature are open metabolic cycles (oMC) with output and input of external substrates (through “metabolic branches”), modulating continuously the enzyme activities and the total concentration of their substrates thorough complex regulatory phenomena. In this work, the transition from a Closed to an open metabolic cycle has been simulated by a consecutive entry and exit of two components through the catalytic action of two enzymes. It is known that after any alteration of the initial conditions, the cycles need a time to reach new equilibrium. We have measured the changes of transition time (T.T.) values in 81 models of CMC differing in Km or vmax values. In general, the T.T. tends to be shorter in cycles with preponderant lower Km and higher vmax values. Further, Mathematica refinement for the estimation of transition time from the data previously calculated can be obtained with the use of the command Interpolating Function.

关键词： Metabolic Cycles Equilibration Times Kinetic Constants Differential Equations Mathematica

Pathological features and diagnosis of intraductal papillary mucinous neoplasm of the pancreas

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World Journal of Gastrointestinal oncology 2014年第9期6卷 311-324页

作者： v.ctor M Castellano-Megías Carolina Ibarrola-de Andrés Guadalupe López-Alonso Francisco Colina-Ruizdelgado Department of Pathology Hospital Universitario de Fuenlabrada Department of Pathology Hospital Universitario "12 de Octubre"

Intraductal papillary mucinous neoplasm(IPMN) of the pancreas is a noninvasive epithelial neoplasm of mucinproducing cells arising in the main duct(MD) and/or branch ducts(BD) of the *** ducts are dilated and filled with neoplastic papillae and mucus in variable *** lacks ovarian-type stroma,unlike mucinous cystic neoplasm,and is defined as a grossly visible entity(≥ 5 mm),unlike pancreatic intraepithelial *** the use of high-resolution imaging techniques,very small IPMNs are increasingly being *** IPMNs are solitary and located in the pancreatic head,although 20%-40% are *** classification in MD type,BD type and mixed or combined type reflects biological differences with important prognostic and preoperative clinical management *** on cytoarchitectural atypia,IPMN is classified into low-grade,intermediategrade and high-grade *** on histological features and mucin(MUC) immunophenotype,IPMNs are classified into gastric,intestinal,pancreatobiliary and oncocytic *** different phenotypes can be observed together,with the IPMN classified according to the predominant *** pathways have been suggested:gastric phenotype corresponds to less aggressive uncommitted cells(MUC1-,MUC2-,MUC5 AC +,MUC6 +) with the capacity to evolve to intestinal phenotype(intestinal pathway)(MUC1-,MUC2 +,MUC5 AC +,MUC6- or weak +) or pancreatobiliary /oncocytic phenotypes(pyloropancreatic pathway)(MUC1 +,MUC 2-,MUC5 AC +,MUC 6 +) becoming more *** of IPMN is excellent but critically worsens when invasive carcinoma arises(about 40% of IPMNs),except in some cases of minimal *** clinical challenge is to establish which IPMNs should be removed because of their higher risk of developing invasive *** resected,they must be extensively sampled or,much better,submitted in its entirety for microscopic study to completely rule out associated invasive carcinoma.

关键词： Mucinous pancreatic cysts Intraductal papillary mucinous neoplasm Main duct intraductal papillary mucinous neoplasm Branch duct intraductal papillary mucinous neoplasm Mucins

Metabolic Cycles: Effect of a Simultaneous Input and output of Two Substrates

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Journal of Biomedical Science and Engineering 2016年第13期9卷 624-637页

作者： Antonio Sillero v.ctor García-Herrero Departamento de Bioquí mica Facultad de Medicina Instituto de Investigaciones Biomédicas Alberto Sols (UAM/CSIC) Arzobispo Morcillo Madrid Spain

The metabolic cycle firstly considered here is composed of a unique initial substrate, six enzymes, and five empty boxes to accommodate the substrates derived from the transformation of the initial substrate. This cycle was considered as a pre-Closed Metabolic Cycle (CMC). Using this model, the influence of changing the kinetic constant values of any enzyme on the substrate concentration was explored. This model was transformed into an open metabolic cycle (oMC) by the input and output of two metabolites catalyzed by two external enzymes. In this case, the relative rates of input and output of metabolites were also examined;it can be concluded that the oMC cycles form delicate and fragile structures which can be theoretically disrupted, making them metabolically unfeasible.

关键词： Metabolic Cycles Metabolic Regulation Kinetic Constants Differential Equations Metabolites: Input and output

Effects of Plant Extracts and Beauveria bassiana on the Activity of Defense-Related Enzymes in Solanum lycopersicum *** Interaction with Fusarium oxysporum ***

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Phyton-International Journal of Experimental Botany 2023年第9期92卷 2503-2518页

作者： JoséAdrian Perez-Robles Carlos Alberto Lecona-Guzmán v.ctor Manuel Ruíz-valdiviezo Joaquín Adolfo Montes-Molina Laboratorio de Biotecnología vegetal Tecnológico Nacional de MexicoCampus Tuxtla GutiérrezTuxtla Gutiérrez29050Mexico

The objective to this work was to evaluate the enzymatic activity in the culture of Solanum lycopersicum *** with Fusarium oxysporum after the combined application of Beauveria bassiana and plant *** lycopersicum plantlets were transplanted 15 days after the *** days after transplanting,Beauveria bassiana spores were applied at a concentration of 1×10^(7)spores mL^(−1)onto soil(along with ***(N)and ***(H)leaf extracts)where *** plants were *** days after transplanting,spores of *** strain were applied at a concentration of 1×10^(6)spores mL^(−1)to soil where *** plants were *** development of *** plants was monitored for 114 days,whereby a randomized complete block treatment design was used,the roots of the plants were crushed with liquid nitrogen,after which Uv/vIS spectrophotometry was used to determine protein concentration,as well as the activity ofβ-1,3-glucanases,peroxidases(PoX,EC1.***.1.7),catalase and *** treatments combining *** and *** and *** extracts,had a significant difference in enzymatic activity levels,thus contributing to better defense mechanisms and a greater protection to *** plants in the presence of *** application of *** and plant extracts to the ground mitigated damage caused by *** on *** plants.

关键词： Glucanases chitinases peroxidases catalase defense mechanisms

Diversity of Saxicolous Lichens along an Aridity Gradient in Central México

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Phyton-International Journal of Experimental Botany 2022年第4期91卷 827-840页

作者： JoséCarmen Soto-Correa Abraham Saldaña-vega v.ctor Hugo Cambrón-Sandoval Laura Concostrina-Zubiri Mariela Gómez-Romero Facultad de Ciencias Naturales Universidad Autónoma de QuerétaroQuerétaro73230México Departamento de Biología y Geología Física y Química Inorgánica Tulipán s/nUniversidad Rey Juan CarlosMóstolesMadrid28933España Cátedra CoNACYT–Facultad de Biología Universidad Michoacana de San Nicolás de HidalgoMoreliaMichoacán58030México

Lichens are symbiotic organisms that comprise a fungus and a photosynthetic partner wich are recognized as a good indicator of climate ***,our understanding of how aridity affects the diversity of saxicolous lichens in drylands is still *** evaluate the relationship between saxicolous lichen diversity and aridity in a central México dryland,a geographical transect was established of 100 km to build an aridity gradient in the semiarid zone of the State of Querétaro,Mexico,comprising ten sampling sites with a 10 km *** richness,abundance and diversity of soil lichen species were recorded using two sampling methods:the quadrat-intercept and the line-intercept method,to compare their performance in assessing soil lichen diversity in *** number of species and Shannon diversity of saxicolous lichens were higher at intermediate values of the aridity index(AI=0.10-0.34).Quadrat intercept and point intercept methods gave quite similar results,which means that the selected method does not influence the results in a significant *** study confirms the role of saxicolous lichens as climate change indicators and reveals the importance of the sampling method selection in the evaluation of different parameters of soil lichen diversity in drylands.

关键词： Climate change drylands ecological indicators environmental stress precipitation temperature

Decreased concentrating capacity in children with febrile urinary tract infection and normal 99mTc-dimercaptosuccinic acid scan:does medullonephritis exist?

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World Journal of Pediatrics 2014年第2期10卷 133-137页

作者： v.ctor García-Nieto Silvia González-Cerrato María Isabel Luis-Yanes Margarita Monge-Zamorano Beatriz Reyes-Millán Pediatric Nephrology Section "Nuestra Senra de la Candelaria"University HospitalSanta Cruz de TenerifeCanary IslandsSpain

Background:Although 99mTc-dimercaptosuccinic acid(DMSA)scan is considered the gold standard for the diagnosis of acute pyelonephritis(AP),sometimes it produces false results in children with clinical features of *** are no studies on the comparison of the sensitivity of DMSA and concentrating capacity ***:Eighty-fi ve infants with AP of less than one year old were studied to evaluate whether they had real AP or *** were compared between infants with an abnormal(group A,n=64)and those with a normal DMSA scan(group B,n=21)respectively.A DDAvP test was performed for each ***:All the infants in both groups presented a high level of C-reactive protein and fever(≥38oC).There were no differences in clinical and analytical variables except C-reactive protein level in the two *** groups exhibited a low urinary osmolality(87.5%in the group A vs.85.7%in the group B).The patients with normal DMSA and decreased concentrating capacity have some renal parenchymal damage and not only a lower urinary *** the infants with an abnormal DMSA scan,33.9%showed renal scars after 6-12 *** infant with a normal DMSA scan showed *** biochemical variables in both groups of infants were not related to vesicoureteral refl ***:Infants with AP,normal DMSA scan and low concentrating capacity may be characterized by a localized infection in the medulla(medullonephritis)or by a false negative DMSA scan.

关键词： concentrating capacity infants pyelonephritis urinary tract infection

Kinetic Rates of the Fischer Tropsch Synthesis on a Co/Nb_2o_5 Catalyst

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Journal of Natural Gas Chemistry 2006年第4期15卷 307-312页

作者： v.ctor R.Ahón Paulo L.C.Lage Carlos D.D.de Souza Fabiana M.Mendes Martin Schmal Federal University of Rio de Janeiro Programa de Engenharia Química COPPE/UFRJ C.P.6850221941-972Rio de JaneiroRJBrazil

The kinetics of the Fischer-Tropsch reaction over a Co/Nb2o5 catalyst in a fixed bed reactor was investigated experimentally. Experiments were carried out under isothermal and isobaric conditions （T=543 K, P=2.1 MPa） and under different conditions of several H2/Co feed molar ratio （0.49-4.79）, space velocities （0.2-3.8 h^-1）, mass of catalyst （0.3-1.5 g）, and Co conversion （10%-29%）. Synthesis gas conversion was measured and data were reduced to estimate the kinetic parameters for different Langmuir-Hinshelwood rate expressions. Differential and integral reactor models were used for the nonlinear regression of kinetics parameters. one of the rate equations could well explain the data. The hydrocarbon product distributions that were experimentally determined exhibited an unusual behavior, and a possible explanation was discussed.

关键词： Fischer-Tropsch natural gas kinetics selectivity

Theoretical Evaluation of Both Unknown Substrate Concentrations and Enzyme Kinetic Constants of Metabolic Cycles

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Journal of Biomedical Science and Engineering 2015年第8期8卷 479-489页

作者： Antonio Sillero v.ctor García-Herrero Departamento de Bioquímica Facultad de Medicina Instituto de Investigaciones Biomédicas Alberto Sols UAM/CSIC Madrid Spain

A formula has been deduced, and named as 2ESKv, relating the concentration of two consecutive substrates of a metabolic cycle with the kinetic constants of the two enzymes involved in their synthesis and degradation. After application of formula 2ESKv to consecutive pairs of substrates and enzymes, a system of interrelated equations was obtained allowing a great variety of theoretical postulates to calculate, back and forth: bunches of unknown enzyme kinetic constants and substrate concentrations, from complementary sets of known data. This vision of a metabolic cycle is of partial application to irreversible pathways and can be useful for modeling and understanding of metabolomics data. To our knowledge, the formula 2ESKv is here described for the first time.

关键词： Metabolic Cycles Evaluation Substrates Evaluation Enzymes Constants Differential Equations Mathematica

Regulation of floral senescence in Arabidopsis by coordinated action of CoNSTANS and jasmonate signaling

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Molecular Plant 2022年第11期15卷 1710-1724页

作者： Gloria Serrano-Bueno Pedro de los Reyes Andrea Chini Gabriel Ferreras-Garrucho v.ctor Sánchez de Medina-Hernández Marta Boter Roberto Solano Federico valverde Plant Development Group Institute for Plant Biochemistry and PhotosynthesisCSIC-Universidad de Sevilla41092 SevillaSpain Department of Plant Molecular Genetics Centro Nacional de BiotecnologíaCSIC28049 MadridSpain Crop Science Centre University of CambridgeCambridge CB3 OLE CambridgeUK Gregor Mendel Institute(GMI) Austrian Academy of SciencesVienna BioCenter(VBC)ViennaAustria

In Arabidopsis,photoperiodic flowering is controlled by the regulatory hub gene CoNSTANS(Co),whereas floral organ senescence is regulated by the jasmonates(JAs).Because these processes are chronologically ordered,it remains unknown whether there are common regulators of both *** this study,we discovered that Co protein accumulates in Arabidopsis flowers after floral induction,and it displays a diurnal pattern in floral organs different from that in the *** observed that altered Co expression could affect flower senescence and abscission by interfering with JA response,as shown by petal-specific transcriptomic analysis as well as Co overexpression in JA synthesis and signaling *** found that Co has a ZIM(ZINC-FINGER INFLoRESCENCE MERISTEM)like domain that mediates its interaction with the JA response repressor JAZ3(jasmonate ZIM-domain 3).Their interaction inhibits the repressor activity of JAZ3,resulting in activation of downstream transcription factors involved in promoting flower ***,we showed that Co,JAZ3,and the E3 ubiquitin ligase CoI1(Coronatine Insensitive 1)could form a protein complex in planta,which promotes the degradation of both Co and JAZ3 in the presence of *** together,our results indicate that Co,a key regulator of photoperiodic flowering,is also involved in promoting flower senescence and abscission by augmenting JA signaling and *** propose that coordinated recruitment of photoperiodic and JA signaling pathways could be an efficient way for plants to chronologically order floral processes and ensure the success of offspring production.

关键词： CoNSTANS flower senescence jasmonic acid