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1.
J Dairy Sci ; 107(6): 3651-3668, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38216038

RESUMO

Dairy farms in the United States have changed in many ways over the past 50 yr. Milk production efficiency has increased greatly, with ∼30% fewer cows producing about twice the amount of milk today. Other improvements include increases in crop yields, fuel efficiency of farm equipment, and efficiency in producing most resources used on farms (e.g. electricity, fuel, fertilizer). These improvements have led to changes in the environmental impact of farms. Through simulation of representative dairy farms in 1971 and 2020, changes in nutrient losses and farmgate life cycle assessments of greenhouse gas (GHG) emissions, fossil energy use, and blue (ground and surface) water use were determined for 6 regions and the United States. For all environmental metrics studied, intensities expressed per unit of fat- and protein-corrected milk produced were reduced, but the total effects over all farms or milk produced increased for 5 of the 13 environmental metrics. Reductions in the impacts of dairy farms in the eastern United States were offset by large increases in western regions because of a major increase in cow numbers in the West. The national average intensity of GHG emissions decreased by 42%, which gave just a 14% increase in the total GHG emissions of all dairy farms over the 50-yr period. The intensity of fossil energy use decreased by 54%, with the total for all farms decreasing by 9%. Water use related to milk production decreased in intensity by 28%, but due to the large increase in dairy production in the dry western regions that have a greater dependence on irrigated feed crops, total blue water use increased by 42%. Major pathways of nitrogen loss included ammonia volatilization, leaching, and denitrification, where total ammonia emissions related to US dairy farms increased by 29%, while leaching losses decreased by 39%, with little change in nitrous oxide emissions. Simulated nitrogen and phosphorus runoff losses totaled for all dairy farms decreased by 27% to 51% through more efficient fertilizer use, reduced tillage, and greater use of cover crops. Emissions of methane and reactive non-methane volatile organic compounds increased by 32% and 53%, respectively, due to greater use of long-term manure storage and silage stored in bunkers and piles. Although much progress has been made in improving production efficiency, continued improvements with new strategies and technologies are needed to meet the demand for dairy products and mitigate total environmental impacts, particularly in view of projected climate variability.


Assuntos
Indústria de Laticínios , Meio Ambiente , Fazendas , Leite , Animais , Estados Unidos , Bovinos , Leite/química , Fertilizantes , Feminino , Gases de Efeito Estufa/análise
2.
Annu Int Conf IEEE Eng Med Biol Soc ; 2018: 718-721, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30440497

RESUMO

Chest x-ray (CXR) analysis is a common part of the protocol for confirming active pulmonary Tuberculosis (TB). However, many TB endemic regions are severely resource constrained in radiological services impairing timely detection and treatment. Computer-aided diagnosis (CADx) tools can supplement decision-making while simultaneously addressing the gap in expert radiological interpretation during mobile field screening. These tools use hand-engineered and/or convolutional neural networks (CNN) computed image features. CNN, a class of deep learning (DL) models, has gained research prominence in visual recognition. It has been shown that Ensemble learning has an inherent advantage of constructing non-linear decision making functions and improve visual recognition. We create a stacking of classifiers with hand-engineered and CNN features toward improving TB detection in CXRs. The results obtained are highly promising and superior to the state-of-the-art.


Assuntos
Tuberculose Pulmonar , Diagnóstico por Computador , Humanos , Pulmão , Redes Neurais de Computação
3.
J Dairy Sci ; 100(10): 7933-7952, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28780094

RESUMO

The present study investigated a cradle-to-grave life cycle assessment to estimate the environmental impacts associated with Italian mozzarella cheese consumption. The differences between mozzarella produced from raw milk and mozzarella produced from curd were studied, and differences in manufacturing processes have been emphasized in order to provide guidance for targeted improvements at this phase. Specifically, the third-largest Italian mozzarella producer was surveyed to collect site-specific manufacturing data. The Ecoinvent v3.2 database was used for secondary data, whereas SimaPro 8.1 was the modeling software. The inventory included inputs from farm activities to end of life disposal of wasted mozzarella and packaging. Additionally, plant-specific information was used to assign major inputs, such as electricity, natural gas, packaging, and chemicals to specific products; however, where disaggregated information was not provided, milk solids allocation was applied. Notably, loss of milk solids was accounted during the manufacture, moreover mozzarella waste and transport were considered during distribution, retail, and consumption phases. Feed production and animal emissions were the main drivers of raw milk production. Electricity and natural gas usage, packaging (cardboard and plastic), transport, wastewater treatment, and refrigerant loss affected the emissions from a farm gate-to-dairy plant gate perspective. Post-dairy plant gate effects were mainly determined by electricity usage for storage of mozzarella, transport of mozzarella, and waste treatment. The average emissions were 6.66 kg of CO2 equivalents and 45.1 MJ of cumulative energy demand/kg of consumed mozzarella produced directly from raw milk, whereas mozzarella from purchased curd had larger emissions than mozzarella from raw milk due to added transport of curd from specialty manufacturing plants, as well as electricity usage from additional processes at the mozzarella plant that are required to process the curd into mozzarella. Normalization points to ecotoxicity as the impact category most significantly influenced by mozzarella consumption. From a farm gate-to-grave perspective, ecotoxicity and freshwater and marine eutrophication are the first and second largest contributors of mozzarella consumption to average European effects, respectively. To increase environmental sustainability, an improvement of efficiency for energy and packaging usage and transport activities is recommended in the post-farm gate mozzarella supply chain.


Assuntos
Queijo , Indústria de Laticínios/métodos , Meio Ambiente , Eutrofização , Manipulação de Alimentos/métodos , Animais , Bases de Dados Factuais , Embalagem de Alimentos , Itália , Leite , Software
4.
Transplant Proc ; 44(9): 2702-5, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23146498

RESUMO

INTRODUCTION: Brain death (BD) is defined as the total irreversible loss of brain stem function. According to the Greek legislation, BD diagnosis is based on clinical criteria that test brain stem function. Bispectral Index Scale (BIS), a parameter derived from a mathematical analysis of the electroengephalogram depicts brain activity. The aim of our study was to record BIS alterations in brain-dead patients. METHODS: Thirty-five brain dead patients according to the clinical criteria were included in this study. All patients were hemodynamically stable, normothermic, and normocapnic, free of oxygenation disturbances and electrolyte abnormalities. Continuous BIS monitoring (BIS XP, A-2000, Aspect Medical Systems, Newton, Mass, USA) was performed in all patients for periods ranging from 24 to 36 hours. RESULTS: BIS values were 0 for the majority of the study period in all patients. However, in 23 patients the BIS value exceeded 30 for more than 30 minutes. This increase could not be attributed to any external stimulation. CONCLUSION: BIS is a noninvasive, easily interpreted method to monitor cerebral activity. According to our results, BIS could be helpful in BD confirmation but cannot replace the valid clinical tests, which are consistent with Greek legislation for this diagnosis.


Assuntos
Morte Encefálica/diagnóstico , Ondas Encefálicas , Encéfalo/fisiopatologia , Eletroencefalografia , Adulto , Regulação da Temperatura Corporal , Morte Encefálica/fisiopatologia , Monitores de Consciência , Eletroencefalografia/instrumentação , Feminino , Hemodinâmica , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Fatores de Tempo
5.
J Dairy Sci ; 94(9): 4243-54, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21854898

RESUMO

The objective of this review is to summarize research efforts and case studies to date of the environmental impacts from dairy processing. The pervasiveness of greenhouse gas emission, water use, consumer waste, and other environmental impacts of dairy are described. An outline of the method of choice, the life cycle assessment, for conducting research and deciding appropriate allocation of the impacts is provided. Specific research examples in dairy processing highlight how the representative final product is associated with environmental impacts to air, water, and land. The primary conclusion from the study was the usefulness of life cycle assessment methodology and the need for further research due to limited studies, variable data, and the magnitude of environmental impact.


Assuntos
Indústria de Laticínios , Meio Ambiente , Animais , Bovinos , Laticínios , Indústria de Processamento de Alimentos , Efeito Estufa , Leite , Eliminação de Resíduos Líquidos , Abastecimento de Água
6.
Inf Process Manag ; 47(5): 676-691, 2011 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-21822350

RESUMO

We present an image retrieval framework based on automatic query expansion in a concept feature space by generalizing the vector space model of information retrieval. In this framework, images are represented by vectors of weighted concepts similar to the keyword-based representation used in text retrieval. To generate the concept vocabularies, a statistical model is built by utilizing Support Vector Machine (SVM)-based classification techniques. The images are represented as "bag of concepts" that comprise perceptually and/or semantically distinguishable color and texture patches from local image regions in a multi-dimensional feature space. To explore the correlation between the concepts and overcome the assumption of feature independence in this model, we propose query expansion techniques in the image domain from a new perspective based on both local and global analysis. For the local analysis, the correlations between the concepts based on the co-occurrence pattern, and the metrical constraints based on the neighborhood proximity between the concepts in encoded images, are analyzed by considering local feedback information. We also analyze the concept similarities in the collection as a whole in the form of a similarity thesaurus and propose an efficient query expansion based on the global analysis. The experimental results on a photographic collection of natural scenes and a biomedical database of different imaging modalities demonstrate the effectiveness of the proposed framework in terms of precision and recall.

7.
Clin Exp Immunol ; 165(3): 318-28, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21649647

RESUMO

CXCL10 is one of the key chemokines involved in trafficking of autoaggressive T cells to the islets of Langerhans during the autoimmune destruction of beta cells in type 1 diabetes (T1D). Blockade of CXCL10 or genetic deletion of its receptor CXCR3 results in a reduction of T1D in animal models. As an alternative to the use of neutralizing monoclonal antibodies to CXCL10 or CXCR3 we evaluated the small molecule CXCR3 antagonist NIBR2130 in a virus-induced mouse model for T1D. We found that the overall frequency of T1D was not reduced in mice administered with NIBR2130. An initial slight delay of diabetes onset was not stable over time, because the mice turned diabetic upon removal of the antagonist. Accordingly, no significant differences were found in the islet infiltration rate and the frequency and activity of islet antigen-specific T cells between protected mice administered with NIBR2130 and control mice. Our data indicate that in contrast to direct inhibition of CXCL10, blockade of CXCR3 with the small molecule antagonist NIBR2130 has no impact on trafficking and/or activation of autoaggressive T cells and is not sufficient to prevent T1D.


Assuntos
Diabetes Mellitus Tipo 1/prevenção & controle , Ergolinas/uso terapêutico , Receptores CXCR3/antagonistas & inibidores , Animais , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/patologia , Movimento Celular/efeitos dos fármacos , Movimento Celular/imunologia , Quimiocina CXCL10/farmacologia , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/etiologia , Diabetes Mellitus Tipo 1/virologia , Modelos Animais de Doenças , Ergolinas/administração & dosagem , Ergolinas/farmacocinética , Ergolinas/farmacologia , Teste de Tolerância a Glucose , Insulina/genética , Insulina/metabolismo , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/patologia , Células Secretoras de Insulina/fisiologia , Interferon gama/metabolismo , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/patologia , Linfonodos/imunologia , Linfócitos/imunologia , Linfócitos/metabolismo , Linfócitos/patologia , Vírus da Coriomeningite Linfocítica/genética , Vírus da Coriomeningite Linfocítica/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Receptores CXCR3/metabolismo , Baço/imunologia , Células Th1/citologia , Proteínas Virais/genética , Proteínas Virais/imunologia
8.
Int J Phytoremediation ; 10(3): 208-19, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18710096

RESUMO

Phytoremediation can be a cost-effective and environmentally acceptable method to clean up crude oil-contaminated soils in situ. Our research objective was to determine the effects of nitrogen (N) additions and plant growth on the number of total hydrocarbon (TH)-, alkane-, and polycyclic aromatic hydrocarbon (PAH)-degrading microorganisms in weathered crude oil-contaminated soil. A warm-season grass, sudangrass (Sorghum sudanense (Piper) Stapf), was grown for 7 wk in soil with a total petroleum hydrocarbon (TPH) level of 16.6 g TPH/kg soil. Nitrogen was added based upon TPH-C:added total N (TPH-C:TN) ratios ranging from 44:1 to 11:1. Unvegetated and unamended controls were also evaluated. The TH-, alkane-, and PAH-degrading microbial numbers per gram of dry soil were enumerated from rhizosphere and non-rhizosphere soil for vegetated pots and non-rhizosphere soil populations were enumerated from non-vegetated pots. Total petroleum-degrading microbial numbers were also calculated for each pot. The TH-, alkane-, and PAH-degrading microbial numbers per gram of dry soil in the sudangrass rhizosphere were 3.4, 2.6, and 4.8 times larger, respectively, than those in non-rhizosphere soil across all N rates. The presence of sudangrass resulted in significantly more TH-degrading microorganisms per pot when grown in soil with a TPH-C:TN ratio of 11:1 as compared to the control. Increased plant root growth in a crude oil-contaminated soil and a concomitant increase in petroleum-degrading microbial numbers in the rhizosphere have the potential to enhance phytoremediation.


Assuntos
Bactérias/metabolismo , Petróleo/análise , Petróleo/metabolismo , Poluentes do Solo/química , Poluentes do Solo/metabolismo , Biodegradação Ambiental , Nitrogênio/metabolismo , Raízes de Plantas/microbiologia , Poaceae/crescimento & desenvolvimento , Poaceae/metabolismo , Poaceae/microbiologia
9.
Am J Transplant ; 8(8): 1604-13, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18557719

RESUMO

Chemokine receptors have gained attention as potential targets for novel therapeutic strategies. We investigated the mechanisms of allograft rejection in chemokine receptor Cxcr3-deficient mice using a model of acute heart allograft rejection in the strain combination BALB/c to C57BL/6. Allograft survival was minimally prolonged in Cxcr3-deficient mice compared to wild-type (wt) animals (8 vs. 7 days) and treatment with a subtherapeutic dose of cyclosporine A (CsA) led to similar survival in Cxcr3-deficient and wt recipients (13 vs. 12 days). At rejection grafts were histologically indistinguishable. Microarray analysis revealed that besides Cxcr3 only few genes were differentially expressed in grafts or in spleens from transplanted or untransplanted animals. Transcript analysis by quantitative RT-PCR of selected cytokines, chemokines, or chemokine receptors or serum levels of selected cytokines and chemokines showed similar levels between the two groups. Furthermore, in a rat heart allograft transplantation model treatment with a small molecule CXCR3 antagonist did not prolong survival despite full blockade of Cxcr3 in vivo. In summary, Cxcr3 deficiency or pharmacologic blockade does not diminish graft infiltration, tempo and severity of rejection. Thus, Cxcr3 does not appear to play a pivotal role in the allograft rejection models described here.


Assuntos
Ciclosporina/administração & dosagem , Rejeição de Enxerto , Sobrevivência de Enxerto , Transplante de Coração/imunologia , Receptores CXCR3/metabolismo , Animais , Camundongos , Camundongos Endogâmicos C57BL , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transplante Homólogo
10.
Int J Phytoremediation ; 8(4): 285-97, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17305303

RESUMO

Phytoremediation can be effective for remediating contaminated soils in situ and generally requires the addition of nitrogen (N) to increase plant growth. Our research objectives were to evaluate seedling emergence and survival of plant species and to determine the effects of N additions on plant growth in crude-oil-contaminated soil. From a preliminary survival study, three warm-season grasses--pearlmillet (Pennisetum glaucum [L.] R. Br.), sudangrass (Sorghum sudanense [Piper] Stapf [Piper]), and browntop millet (Brachiaria ramosa L.)--and one warm-season legume--jointvetch (Aeschynomene americana L.)--were chosen to determine the influence of the N application rate on plant growth in soil contaminated with weathered crude oil. Nitrogen was added based on total petroleum hydrocarbon-C:added N ratios (TPH-C:TN) ranging from 44:1 to 11:1. Plant species were grown for 7 wk. Root and shoot biomass were determined and root length and surface area were analyzed. Pearlmillet and sudangrass had higher shoot and root biomass when grown at a TPH-C:TN (inorganic) ratio of 11:1 and pearlmillet had higher root length and surface area when grown at 11:1 compared with the other species. By selecting appropriate plant species and determining optimum N application rates, increased plant root growth and an extended rhizosphere influence should lead to enhanced phytoremediation of crude-oil-contaminated soil.


Assuntos
Fabaceae/metabolismo , Hidrocarbonetos/farmacocinética , Nitrogênio/farmacologia , Petróleo , Poaceae/metabolismo , Poluentes do Solo/farmacocinética , Biodegradação Ambiental , Biomassa , Fabaceae/crescimento & desenvolvimento , Fertilizantes , Humanos , Resíduos Industriais/prevenção & controle , Raízes de Plantas , Brotos de Planta , Poaceae/crescimento & desenvolvimento , Estações do Ano
11.
Int J Phytoremediation ; 5(2): 125-36, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12929495

RESUMO

Phytoremediation is an attractive treatment technology for many contaminated sites due to its cost effectiveness and public acceptance. We present a sensitivity analysis of important parameters from a screening level model for phytoremediation by grass species of weathered petroleum-contaminated sites. The conceptual framework is that root movement through contaminated soil will enhance contaminant biodegradation by providing a local environment more favorable for petroleum degrading microorganisms--the so-called rhizosphere effect. Common questions in phytoremediation are, "What species should be planted?" and "What management practices should be followed?" These choices may affect degradation kinetics, root biomass (and therefore rhizosphere volume), and the root turnover. Important model parameters are the rate constants, rhizosphere volume, and the rate of root turnover. We present a sensitivity analysis with the aim of identifying the most important factors for improving phytoremediation effectiveness. For simulations of the phytoremediation of weathered diesel range organics, our results indicate that annual species, with higher root turnover, are preferred over perennial species with the caveat of equal degradation rate constants, that is, no species-dependent effects. In addition, the results suggest that the management of nonrhizosphere soil could play an important role in the overall effectiveness of phytoremediation. Finally, the effect of increasing root biomass or increasing the rhizosphere thickness is approximately equivalent with respect to the ultimate removal of the contaminants.


Assuntos
Poluição Ambiental/estatística & dados numéricos , Modelos Biológicos , Petróleo/metabolismo , Plantas/metabolismo , Poluentes do Solo/metabolismo , Desenvolvimento Vegetal , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Sensibilidade e Especificidade , Estados Unidos
12.
Int J Phytoremediation ; 5(1): 41-55, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12710234

RESUMO

We present a simple model for root length density that combines the generally accepted spatial (exponential decrease with depth) and temporal (sinusoidal) variability of root length. Parameters in this model for root length density can be determined from assumed or measured information regarding the annual biomass turnover, maximum standing biomass, and maximum depth of root penetration. The root length density model, coupled with information regarding the average root lifespan, gives specific root growth and senescence functions that are the forcing functions for the phytoremediation model. We present a screening level mathematical model for phytoremediation that accounts for the growth and senescence of roots in the system. This is an important factor for recalcitrant, immobile compounds found in weathered crude oil contaminated soils. The phytoremediation model is based on variable volume compartments that have individual first-order degradation rate constants; as the roots move through the soil, the soil cycles through the rhizosphere zone, decaying root zone and bulk soil zone. Thus, although the oil is immobile, as the roots penetrate through the soil the oil is brought into contact with the rhizosphere.


Assuntos
Modelos Biológicos , Petróleo/metabolismo , Raízes de Plantas/metabolismo , Plantas/metabolismo , Poluentes do Solo/metabolismo , Algoritmos , Apoptose/fisiologia , Biodegradação Ambiental , Desenvolvimento Vegetal , Raízes de Plantas/crescimento & desenvolvimento
13.
Int J Phytoremediation ; 5(4): 381-97, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-14750564

RESUMO

Phytoremediation can be a viable alternative to traditional, more costly remediation techniques. Three greenhouse studies were conducted to evaluate plant growth with different soil amendments in crude oil-contaminated soil. Growth of alfalfa (Medicago sativa L., cultivar: Riley), bermudagrass (Cynodon dactylon L., cultivar: Common), crabgrass (Digitaria sanguinalis, cultivar: Large), fescue (Lolium arundinaceum Schreb., cultivar: Kentucky 31), and ryegrass (Lolium multiflorum Lam., cultivar: Marshall) was determined in crude oil-contaminated soil amended with either inorganic fertilizer, hardwood sawdust, papermill sludge, broiler litter or unamended (control). In the first study, the addition of broiler litter reduced seed germination for ryegrass, fescue, and alfalfa. In the second study, bermudagrass grown in broiler litter-amended soil produced the most shoot biomass, bermudagrass produced the most root biomass, and crabgrass and bermudagrass produced the most root length. In the third study, soil amended with broiler litter resulted in the greatest reduction in gravimetric total petroleum hydrocarbon (TPH) levels across the six plant treatments following the 14-wk study. Ryegrass produced more root biomass than any other species when grown in inorganic fertilizer- or hardwood sawdust + inorganic fertilizer-amended soil. The studies demonstrated that soil amendments and plant species selection were important considerations for phytoremediation of crude oil-contaminated soil.


Assuntos
Petróleo , Plantas/efeitos dos fármacos , Esgotos , Poluentes do Solo , Cynodon/efeitos dos fármacos , Cynodon/fisiologia , Digitaria/efeitos dos fármacos , Digitaria/fisiologia , Humanos , Lolium/efeitos dos fármacos , Lolium/fisiologia , Medicago/efeitos dos fármacos , Medicago/fisiologia
15.
Bioorg Med Chem Lett ; 11(7): 923-5, 2001 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-11294392

RESUMO

The synthesis of the highly potent E-selectin inhibitor 5 is described. Sialyl Lewis X mimic 5 was rationally designed by combining two previously disclosed beneficial sLe(x) modifications in a single molecule. The compound was found to be 30-fold more potent than sLe(x) in a static, cell-free equilibrium assay. Furthermore, compound 5 was highly active (IC50 = 10 microM) in a dynamic non-equilibrium assay in which sLe(x) did not inhibit neutrophil rolling at up to 1000 microM.


Assuntos
Movimento Celular/efeitos dos fármacos , Selectina E/efeitos dos fármacos , Neutrófilos/efeitos dos fármacos , Oligossacarídeos/química , Oligossacarídeos/síntese química , Oligossacarídeos/farmacologia , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos , Endotélio/citologia , Glucosamina/química , Humanos , Concentração Inibidora 50 , Ácido N-Acetilneuramínico/química , Neutrófilos/fisiologia , Antígeno Sialil Lewis X , Veias Umbilicais/citologia
16.
Phytochemistry ; 56(2): 153-9, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11219807

RESUMO

In many cases, the vacuolar uptake of secondary metabolites has been demonstrated to be strictly specific for a given compound and plant species. While most plants contain glycosylated secondary substances, few cases are known where flavonoids may also carry negative charges, e.g. as glucuronide conjugates. Vacuolar transport of glucosylated phenylpropanoid derivatives has been shown to occur by proton substrate antiport mechanisms (Klein, M., Weissenböck. G., Dufaud, A., Gaillard, C., Kreuz, K., Martinoia, E., 1996. Different energization mechanisms drive the vacuolar uptake of a flavonoid glucoside and a herbicide glucoside. J. Biol. Chem. 271, 29,666-29,671). In contrast, flavone glucuronides appearing specifically in rye mesophyll vacuoles are taken up by direct energisation utilising MgATP, strongly arguing for the presence of an ATP-binding cassette (ABC) transporter belonging to the subfamily of multidrug resistance-associated proteins (MRP) on the rye vacuolar membrane (Klein, M., Martinoia, E., Hoffmann-Thoma, G., Weissenböck, G., 2000. A membrane-potential dependent, ubiquitous ABC-like transporter mediates the vacuolar uptake of rye flavone glucuronides regulation of glucturonide uptake by glutathione and its conjugates. Plant Journal 21, 289-304). MRPs are known to transport negatively charged organic anions. Results presented here suggest that the vacuolar directly energised MRP-like glucuronate pump for plant-specific flavone glucuronides is ubiquitously present in diverse plant species since rye flavone glucuronides are taken up into vacuoles isolated from the barley mesophyll or from the broccoli stalk parenchyma representing two species which do not synthesise glucuronidated secondary compounds. According to the transport characteristics and inhibition profile observed we propose the existence of a high-capacity, uncoupler-insensitive vacuolar ABC transporter for flavone glucuronides and possibly other negatively charged organic compounds -- plant-born or xenobiotic -- irrespective of the plant's capability to endogenously produce glucuronidated compounds.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Flavonoides/metabolismo , Glucuronídeos/metabolismo , Secale/metabolismo , Vacúolos/metabolismo , Especificidade da Espécie
17.
Planta ; 212(2): 231-42, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11216844

RESUMO

Minor-vein ultrastructure and sugar export were studied in mature summer and winter leaves of the three broadleaf-evergreen species Ajuga reptans var. artropurpurescens L., Aucuba japonica Thunb. and Hedera helix L. to assess temperature effects on phloem loading. Leaves of the perennial herb Ajuga exported substantial amounts of assimilates in form of raffinose-family oligosaccharides (RFOs). Its minor-vein companion cells represent typical intermediary cells (ICs), with numerous small vacuoles and abundant plasmodesmal connectivity to the bundle sheath. The woody plants Hedera and Aucuba translocated sucrose as the dominant sugar species, and only traces of RFOs. Their minor-vein phloem possessed a layer of highly vacuolated cells (VCs) intervening between mesophyll and sieve elements. Depending on their location and ontogeny, VCs were classified either as companion or parenchyma cells. Both cell types showed symplasmic continuity to the adjacent mesophyll tissue although at a lower plasmodesmal frequency compared to the Ajuga ICs. p-Chloromercuribenzenesulfonic acid did not reduce leaf sugar export in any of the plants, indicating a symplasmic mode of phloem loading. Winter leaves did not show symptoms of frost injury, and the vacuolar pattern in ICs and VCs was equally prominent in both seasons. Starch accumulation as a result of reduced phloem loading was not observed to be triggered by low temperature. In contrast, high amounts of starch were found in mesophyll and bundle-sheath cells of summer leaves. Physiological data on season-dependent leaf exudation showed the maintenance of sugar export in cold-acclimated winter leaves.


Assuntos
Metabolismo dos Carboidratos , Árvores/metabolismo , Transporte Biológico , Microscopia Eletrônica , Folhas de Planta/metabolismo , Folhas de Planta/ultraestrutura , Estações do Ano , Especificidade da Espécie
18.
Blood ; 96(10): 3585-91, 2000 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-11071658

RESUMO

Selectin-dependent rolling is the earliest observable event in the recruitment of leukocytes to inflamed tissues. Several glycoproteins decorated with sialic acid, fucose, and/or sulfate have been shown to bind the selectins. The best-characterized selectin ligand is P-selectin glycoprotein-1 (PSGL-1) that supports P-selectin- dependent rolling in vitro and in vivo. In vitro studies have suggested that PSGL-1 may also be a ligand for E- and L-selectins. To study the in vivo function of PSGL-1, without the influence of other leukocyte proteins, the authors observed the interaction of PSGL-1-coated microspheres in mouse venules stimulated to express P- and/or E-selectin. Microspheres coated with functional recombinant PSGL-1 rolled in surgically stimulated and tumor necrosis factor alpha (TNFalpha)-stimulated mouse venules. P-selectin deficiency or inhibition abolished microsphere rolling in surgically and TNFalpha-stimulated venules, whereas E-selectin deficiency or inhibition increased microsphere rolling velocity in TNFalpha-stimulated venules. The results suggest that P-selectin-PSGL-1 interaction alone is sufficient to mediate rolling in vivo and that E-selectin-PSGL-1 interaction supports slow rolling.


Assuntos
Selectina E/farmacologia , Glicoproteínas de Membrana/fisiologia , Selectina-P/farmacologia , Animais , Selectina E/metabolismo , Hemodinâmica , Humanos , Leucócitos/efeitos dos fármacos , Leucócitos/metabolismo , Leucócitos/fisiologia , Masculino , Glicoproteínas de Membrana/metabolismo , Glicoproteínas de Membrana/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microesferas , Modelos Animais , Neutrófilos/química , Selectina-P/metabolismo , Fatores de Tempo , Fator de Necrose Tumoral alfa/farmacologia , Vênulas/química , Vênulas/metabolismo , Vênulas/fisiologia
19.
Plant J ; 21(3): 289-304, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10758480

RESUMO

In this paper we present results on the vacuolar uptake mechanism for two flavone glucuronides present in rye mesophyll vacuoles. In contrast to barley flavone glucosides (Klein et al. (1996) J. Biol. Chem. 271, 29666-29671), the flavones luteolin 7-O-diglucuronyl-4'-O-glucuronide (R1) and luteolin 7-O-diglucuronide (R2) were taken up into vacuoles isolated from rye via a directly energized mechanism. Kinetic studies suggested that the vacuolar glucuronide transport system is constitutively expressed throughout rye primary leaf development. Competition experiments argued for the existence of a plant MRP-like transporter for plant-specific and non-plant glucuronides such as beta-estradiol 17-(beta-D-glucuronide) (E217G). The interaction of ATP-dependent vacuolar glucuronide uptake with glutathione and its conjugates turned out to be complex: R1 transport was stimulated by dinitrobenzene-GS and reduced glutathione but was inhibited by oxidized glutathione in a concentration-dependent manner. In contrast, R2 uptake was not increased in the presence of reduced glutathione. Thus, the transport system for plant-derived glucuronides differed from the characteristic stimulation of vacuolar E217G uptake by glutathione conjugates but not by reduced glutathione (Klein et al. (1998) J. Biol. Chem. 273, 262-270). Using tonoplast vesicles isolated with an artificial K+ gradient, we demonstrate for the first time for plant MRPs that the ATP-dependent uptake of R1 is membrane-potential dependent. We discuss the kinetic capacity of the ABC-type glucuronide transporter to explain net vacuolar flavone glucuronide accumulation in planta during rye primary leaf development and the possibility of an interaction of potential substrates at both the substrate binding and allosteric sites of the MRP transporter regulating the activity towards a certain substrate.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Flavonoides/metabolismo , Glucuronídeos/metabolismo , Glutationa/análogos & derivados , Glutationa/farmacologia , Secale/metabolismo , Vacúolos/metabolismo , Trifosfato de Adenosina/metabolismo , Ácidos e Sais Biliares/metabolismo , Transporte Biológico/efeitos dos fármacos , Glucuronatos/metabolismo , Homeostase , Cinética , Luteolina , Folhas de Planta , Trítio , Vacúolos/efeitos dos fármacos
20.
J Med Chem ; 42(23): 4909-13, 1999 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-10579852

RESUMO

An early step of the inflammatory response-the rolling of leukocytes on activated endothelial cells-is mediated by selectin/carbohydrate interactions. The tetrasaccharide sialyl Lewis(x) (sLe(x)) 1 is a ligand for E-, P-, and L-selectin and, therefore, serves as a lead structure to develop analogues which allow the control of acute and chronic inflammation. Here we describe the efficient synthesis (10 linear steps) of the potent sLe(x) mimetic 2. Compared to sLe(x), compound 2 showed a 30-fold improved affinity in a static, cell-free E-selectin-ligand binding assay (IC(50) = 36 microM). These data were confirmed by a marked inhibition in an in vitro cell-cell rolling assay which simulates in vivo conditions (IC(50) approximately 40 microM). The assays are predictive for the in vivo efficacy of test compounds as indicated by a marked inhibitory effect of 2 in a thioglycollate induced peritonitis model of acute inflammation in mice (ED(50) approximately 15 mg/kg).


Assuntos
Selectina E/metabolismo , Oligossacarídeos/síntese química , Doença Aguda , Animais , Sequência de Carboidratos , Ligantes , Camundongos , Mimetismo Molecular , Dados de Sequência Molecular , Oligossacarídeos/química , Oligossacarídeos/farmacologia , Peritonite/induzido quimicamente , Peritonite/tratamento farmacológico , Antígeno Sialil Lewis X , Relação Estrutura-Atividade , Tioglicolatos
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