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1.
Artigo em Inglês | MEDLINE | ID: mdl-37239572

RESUMO

BACKGROUND: Lack of access to adequate, safe, and nutritious food is a major concern for the Afghan population due to ongoing war and humanitarian crises. Recently resettled Afghan refugees in the US continue to face challenges securing adequate, nutritious food resources in new environments. This study examined Afghan refugees' food access and insecurity in the San Joaquin Valley, California. METHODS: Semi-structured, in-depth interviews were conducted to collect the perspectives and experiences of key informants and newly arrived Afghan refugees. RESULTS: This study highlights environmental and structural factors (availability and accessibility of grocery stores; availability of religious-appropriate items in the stores; the public benefit received by a family; and public transportation) and individual factors (religious and cultural practices; financial and language barriers) as major determinants of post-resettlement food insecurity. CONCLUSION: Increasing the accessibility and affordability of culturally and religiously appropriate food items within the US food system, enhancing the collaboration of community volunteers and resettlement organizations in the direct assistance of new families, and providing continuous access to public benefits are possible steps to mitigate the risk of food insecurity among Afghan refugees. This study suggests a continuous examination of the degree of food insecurity in this population and its attendant health impacts.


Assuntos
Refugiados , Humanos , Meio Ambiente , Abastecimento de Alimentos , Alimentos , Insegurança Alimentar
2.
J Agric Food Chem ; 69(44): 13217-13226, 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34706532

RESUMO

The enzymatic production of xylo-oligosaccharides (XOs) from destarched wheat bran with a GH11 xylanase was studied. Xylo-oligosaccharides (XOs) produced were separated into different fractions according to their degree of polymerization (DP) and the nature of their substituents: arabinoxylo-oligosaccharides (AXOs) with a DP from 2 to 3 and DP from 2 to 6 and feruloylated arabinoxylo-oligosaccharides (FAXOs) esterified by ferulic and p-coumaric acids with a DP from 3 to 6. Both AXOs (short and long DP) and FAXOs stimulated the growth of Bifidobacterium adolescentis, Faecalibacterium prausnitzii, and Prevotella copri similarly but not Lactobacillus rhamnosus. The utilization of AXOs and FAXOs as a carbon source resulted in the increase in turbidity, decrease in pH, and production of short-chain fatty acids (SCFAs) in the culture broth. The highest amount of SCFAs was produced by F. prausnitzii using FAXOs. Results suggest that FAXOs and AXOs have the potential to be considered as prebiotics.


Assuntos
Fibras na Dieta , Probióticos , Bactérias/genética , Carbono , Oligossacarídeos , Polimerização , Prebióticos , Prevotella , Xilanos
3.
Gene ; 738: 144371, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32001375

RESUMO

MCTPs (multiple C2 domain proteins with two transmembrane regions) have been proposed as novel endoplasmic reticulum calcium sensors; however, their function remains largely unknown. Here we report the structure of the four mctp genes from zebrafish (mctp1a, mctp1b, mctp2a and mctp2b), their diversity, expression pattern during embryonic development and in adult tissue and the effect of knocking down the expression of Mctp2b by CRISPR/Cas9. The four mctp genes are expressed from early development and exhibit differential expression patterns but are found mainly in the nervous and muscular systems. Mctp2b tagged with fluorescent proteins and expressed in HEK-293 cells and neurons of the fish spinal cord localized mostly in the endoplasmic reticulum but also in lysosomes and late and recycling endosomes. Knocking down mctp2b expression impaired embryonic development, suggesting that the functional participation of this gene is relevant, at least during the early stages of development.


Assuntos
Proteínas de Membrana/metabolismo , Alelos , Animais , Sistemas CRISPR-Cas , Cálcio/metabolismo , Desenvolvimento Embrionário/genética , Retículo Endoplasmático/metabolismo , Mutação da Fase de Leitura/genética , Regulação da Expressão Gênica no Desenvolvimento/genética , Células HEK293 , Humanos , Proteínas de Membrana/genética , Receptores de Detecção de Cálcio/genética , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética
4.
Methods Mol Biol ; 1821: 3-20, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30062401

RESUMO

The Rho family of GTPases are known to play pivotal roles in the regulation of fundamental cellular processes, ranging from cell migration and polarity to wound healing and regulation of actin cytoskeleton. Over the past decades, accumulating experimental work has increasingly mapped out the mechanistic details and interactions between members of the family and their regulators, establishing detailed interaction circuits within the Rho GTPase signaling network. These circuits have served as a vital foundation based on which a multitude of mathematical models have been developed to explain experimental data, gain deeper insights into the biological phenomenon they describe, as well as make new testable predictions and hypotheses. Due to the diverse nature and purpose of these models, they often vary greatly in size, scope, complexity, and formulation. Here, we provide a systematic, categorical, and comprehensive account of the recent modeling studies of Rho family GTPases, with an aim to offer a broad perspective of the field. The modeling limitations and possible future research directions are also discussed.


Assuntos
Simulação por Computador , Modelos Biológicos , Transdução de Sinais/fisiologia , Proteínas rho de Ligação ao GTP/metabolismo , Animais , Humanos
5.
Food Chem ; 240: 1106-1112, 2018 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-28946230

RESUMO

This study reports the formation of 2-furomethyl-amino acids (2-FM-AA) as indicators of Maillard reaction (MR) in black garlic elaboration, followed by the determination of furosine by ion-pair RP-HPLC-UV. The method was assessed for accuracy, repeatability and detection and quantitation limits indicating its adequacy. Traditional procedure of black garlic obtainment and the inclusion of convective drying (CDP) and ohmic heating (OHP) were assayed. For comparison purposes, three commercial black garlic samples were used. Together with furosine (2-FM-lysine), 2-furoylmethyl-γ-aminobutyric acid and 2-FM-arginine were detected. Levels of furosine were higher in CDP (46.6-110.1mg/100g protein) than in OHP (13.7-42.0mg/100g protein) samples, probably due to the most severe processing conditions used in the former. These results highlight the suitability of 2-FM-AA as chemical indicators to monitor the process of black garlic elaboration in order to obtain high quality products.


Assuntos
Aminoácidos/análise , Alho , Reação de Maillard
6.
Antimicrob Agents Chemother ; 59(9): 5804-13, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26169411

RESUMO

An evaluation of the leishmanicidal activity in vitro and in vivo of hypericin, an expanded-spectrum photosensitizer found in Hypericum perforatum, is presented. Hypericin was evaluated against intracellular amastigotes in vitro of Leishmania (Viannia) panamensis. A topical formulation containing 0.5% hypericin was developed and assayed in vivo in a hamster model of cutaneous leishmaniasis. Results demonstrate that hypericin induces a significant antiamastigote effect in vitro against L. panamensis by decreasing the number of parasites inside infected cells. The topical formulation of 0.5% hypericin allows healing of L. panamensis-induced lesions upon a topical application of 40 mg/day plus visible-light irradiation (5 J/cm(2), 15 min), twice a week for 3 weeks.


Assuntos
Leishmaniose Cutânea/tratamento farmacológico , Perileno/análogos & derivados , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/uso terapêutico , Animais , Antracenos , Linhagem Celular , Cricetinae , Humanos , Leishmania/efeitos dos fármacos , Leishmania/patogenicidade , Leishmaniose Cutânea/terapia , Perileno/uso terapêutico , Células U937 , Cicatrização/efeitos dos fármacos
7.
J Environ Sci Health B ; 48(2): 122-32, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23305280

RESUMO

This study investigates the effects of chlorothalonil (CLT) on chemical oxygen demand (COD) and dissolved organic carbon (DOC) in pilot-scale horizontal subsurface flow constructed wetlands (HSSFCW) planted with Phragmites australis. Physicochemical parameters of influent and effluent water samples, microbial population counting methods and statistical analysis were used to evaluate the influence of CLT on organic matter removal efficiency. The experiments were conducted on four planted replicate wetlands (HSSFCW-Pa) and one unplanted control wetland (HSSFCW-NPa). The wetlands exhibited high average organic matter removal efficiencies (HSSFCW-Pa: 80.6% DOC, 98.0% COD; HSSFCW-NPa: 93.2% DOC, 98.4% COD). The addition of CLT did not influence organic removal parameters. In all cases CLT concentrations in the effluent occurred in concentrations lower than the detection limit of the analytical method. Microbial population counts from HSSFCW-Pa showed significant correlations among different microbial groups and with different physicochemical variables. The apparent independence of organic matter removal and CLT inputs, along with the CLT depletion observed in effluent samples demonstrated that HSSFCW are a viable technology for the treatment of agricultural effluents contaminated with organo-chloride pesticides like CLT.


Assuntos
Fenômenos Fisiológicos Bacterianos , Biofilmes/efeitos dos fármacos , Carbono/metabolismo , Fungicidas Industriais/metabolismo , Nitrilas/metabolismo , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , Análise da Demanda Biológica de Oxigênio , Cromatografia Gasosa , Monitoramento Ambiental , Compostos Orgânicos/metabolismo , Projetos Piloto , Poaceae/crescimento & desenvolvimento , Áreas Alagadas
8.
Hig. aliment ; 26(212/213): 81-86, set.-out. 2012.
Artigo em Português | LILACS | ID: lil-696174

RESUMO

Os pequenos frutos estão em evidência por seu potencial de industrialização e também pela presença de compostos antioxidantes. Recentes pesquisas estão, aos poucos, desvendando os pequenos frutos e suas vantagens à saúde humana. A soma desse conhecimento e do potencial que o Brasil tem em produzir esses frutos vem incentivar o consumo destes e novas pesquisas, o que pode, consequentemente, aumentar a proteção contra os efeitos deletérios dos radicais livres. Em função disso, esta revisão discute a relação do potencial antioxidante da amora, framboesa, morango e seu benefício à saúde. Pode-se concluir que a variedade de compostos existentes nos pequenos frutos, além da multiplicidade genética, edafoclimática, métodos de processamento e acondicionamento dos pequenos frutos estudados, confere amplo e diferenciado espectro de capacidade antioxidante a esses, conferindo-os efeitos antiprolifereativos e anticarcinogênicos. Com isto, percebe-se a razão da crescente industrialização e o motivo do estímulo ao consumo dos pequenos frutos em questão.


Assuntos
Composição de Alimentos , Fragaria , Frutas/microbiologia , Antioxidantes/análise , Radicais Livres , Compostos Fenólicos
9.
Folia Microbiol (Praha) ; 57(1): 11-4, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22135095

RESUMO

Simkania negevensis is an obligate intracellular bacterium grouped into the order Chlamydiales. This new amoeba-resistant bacterium represents a novel aetiologic agent of bronchiolitis and community-acquired pneumonia in both adults and children. It has been suggested that Simkania could be an ubiquitous microorganism presented in water environments. In the natural history of infections with amoeba-related bacteria encountered in aquatic habitats, the transmissions by environmental aerosols or contaminated water/air systems have been extensively recognized. Therefore, understanding the feasibility of Simkania infection by these or similar routes is relevant. In the present work, we investigated the prevalence of this novel disease-associated microorganism in water samples from different sources by real-time PCR (qPCR). Our results show Simkania detection in 5 of 185 water analyzed samples (2.7%: 2 of 88 cooling towers and 3 of 8 waste water samples). However, no Simkania was detected in a drinking water.


Assuntos
Chlamydiales/isolamento & purificação , Microbiologia da Água , Poluição da Água , Chlamydiales/classificação , Chlamydiales/genética , Infecções Respiratórias/microbiologia , Espanha
10.
Rev. enferm. UFSM ; 1(3): 497-505, set.-dez. 2011.
Artigo em Português | BDENF - Enfermagem | ID: biblio-1034034

RESUMO

Relato de experiência de extensão universitária, desenvolvida com grupos de gestantes e familiares. O objetivo do relato é compartilhar a experiência e discutir, à luz da teoria Pichoniana, acerca dos motivos que justificam o uso de disparadores temáticos em grupos de gestantes e familiares. A atividade é interdisciplinar, reunindo docentes e acadêmicos de Enfermagem, Nutrição, Fisioterapia e Psicologia, por meio do emprego da metodologia de grupos operativos. O uso dos disparadores temáticos junto aos grupos de gestantes e familiares tem contribuído para dar suporte terapêutico a essas pessoas quando vivenciam acontecimento que contribui para mudar-lhes a vida – a gestação de um filho. Em virtude do caráter interdisciplinar, a atividade tem estimulado o trabalho em grupo e contribuído para a formação de um novo Esquema Conceitual Referencial Operativo para cada professor e estudante e para o grupo como um todo.


Academic extension experience report, developed with pregnat women and their family members. This report aims to share the experience and discuss, according to Pichonian theory, about the reason that justifies the use of thematic triggers in pregnant women and family members. The activity is interdisciplinary, congregating teachers and students of Nursing, Nutrition, Physiotherapy and Psychology, who use the operative groups’ methodology. The use of the thematic triggers, in pregnant women and family members, has contributed to carry out the task, for therapeutic support to people who experience event that contributes to change their lives – the pregnancy. Because its interdisciplinary characteristic, the accounted activity, has stimulated the work in group and contributed to the formation of a new Operative Reference Conceptual Scheme to each teacher and student and to the group as a whole.


Relato de experiencia de extensión universitaria desarrollado con grupos de gestantes y familiares. El objetivo del relato es compartir experiencias y discutir, a la luz del referencial de la Teoría Pichoniana, sobre los motivos que justifican el uso de disparadores temáticos en las mujeres embarazadas y sus familiares. La actividad es interdisciplinar y reúne los profesores y académicos de Enfermería, Nutrición, Fisioterapia y Psicología, mediante el empleo de la metodología de los grupos operativos. El uso de los disparadores temáticos a lo largo de los grupos de gestantes y sus familias ha contribuido para dar soporte terapéutico a estas personas cuando viven un acontecimiento que contribuye a cambiar sus vidas - el embarazo de un hijo. Debido a la naturaleza interdisciplinar, esta actividad ha fomentado el trabajo en equipo y contribuyó a la formación de un nuevo Esquema Conceptual Referencial Operativo para cada profesor y el alumno y para el grupo en su conjunto.


Assuntos
Humanos , Educação , Enfermagem , Família , Gestantes , Psicologia Social
11.
J Water Health ; 9(2): 312-6, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21942196

RESUMO

Simkania negevensis is an obligate intracellular bacterium grouped into the order Chlamydiales. This new amoeba-resistant intracellular bacterium might represent a novel etiologic agent of bronchiolitis and community-acquired pneumonia and occurs in aquatic habitats such as drinking water and reclaimed wastewater. Another amoeba-related bacterium, Legionella pneumophila, is an etiologic agent of pneumonia transmitted by environmental aerosols or contaminated water/air cooling systems. These transmission pathways are important in the natural history of Legionellae infections and possibly other intracellular microorganisms such as Parachlamydiaceae; thus, understanding the feasibility of Simkania infection by these routes is relevant. In the present work, we investigated the prevalence of this newly identified pathogenic bacterium in cooling towers by quantitative PCR (qPCR) and its possible relationship with Legionella pneumophila co-infection. Our results show Simkania detection in 2 of 70 cooling towers analyzed. To our knowledge, this report is the first describing Simkania negevensis detection in this category of environmental water samples.


Assuntos
Chlamydiales/isolamento & purificação , Microbiologia da Água , Ar Condicionado , Contagem de Colônia Microbiana , Doenças Transmissíveis Emergentes/microbiologia , Indústrias , Legionella pneumophila/isolamento & purificação , Reação em Cadeia da Polimerase , Prevalência , Espanha
12.
Bol. venez. infectol ; 20(1): 28-32, ene.-jun. 2009.
Artigo em Espanhol | LILACS | ID: lil-721097

RESUMO

Describir y evaluar cinco brotes epidémicos de leishmaniasis tegumentaria americana (LTA) en grupos familiares de los estados Miranda y Aragua y de la República de Colombia. Trece pacientes de grupos familiares diferentes acudieron al Instituto de Medicina Tropical por lesiones ulcerosas en regiones anatómicas expuestas; siete del sexo masculino en edades entre 2 y 66 años. La leishmanina, los anticuerpos fluorescentes anti-leishmania y los frotis por aposición de segmentos de piel de las úlceras revelaron la presencia del parásito leishmania spp. Se efectuaron exámenes bioanalíticos y cardiovasculares recomendados para el tratamiento con antimoniatos pentavalentes. Siete pacietes fueron tratados ambulatoriamente con meglumina intramuscular a la dosis de 3000 mg/día en series terapéuticas de 10 días con una segunda serie luego del reposo de 10 días. Una paciente adulta recibió tres series de AM, la última de ellas de 4500 mg/kg/día 10 días en hospitalización. Cinco niños fueron hospitalizados y recibieron AM a la dosis de 70 mg/día/10 días con reposo intermedio y una segunda serie. Los pacientes respondieron adecuadamente a la terapia empleada con la cicatrización completa de los procesos ulcerosos. La LTA siguen adquiriéndola pobladores y viajeros de las áreas rurales de Venezuela y Colombia y frecuentemente se presenta como brotes epidémicos familiares, lo cual facilita el diagnóstico presuntivo. El caso índice permite el diagnóstico de la enfermedad entre otros familiares. Los casos tratados comprueban una vez más las ventajas terapéuticas de la meglumina en LTA.


Leishmaniasis is an infectious disease acquired with relative frequency in the rural areas of Venezuela and Colombia. When there is the antecedent of another member of the family with a similar symptom "at home there is somebody with a similar ulcer" is a frequent statement that facilitates the diagnosis. To describe and evaluate five epidemic autbreaks of cutaneous leishmaniasis of the New World (CLNW) in family groups of Miranda and Aragua states in Venezuela and North Santander Department in Colombia, including diagnosis and treatment with meglumine. This disease is relatively frequently acquired by inhabitants and travelers to these geographical regions. Thirteen patients of different family groups, attended to the "Instituto de Medicina Tropical" (IMT) and to the "Hospital Universitario de Caracas" (HUC) presenting an ulcerative lesión on an exposed area of skin, compatible with the clínical diagnosis of this parasitic disease. Seven patients were females with age between 2 and 66 years. Laboratory diagnostic exams included the intradermal reaction test "leishmanina" serology tests for determination of antibodies anti-leismania and apposition smear from the ulcers stained by the Giemsa method, resulted positive for the infection produced by parasites of the species Leishmania spp. Six patients adults received treatment as outpatients with two series of the pentavalent antimony meglumine at a dose of 3000 mg/day during 10 days, one patient received the dose of 4500 mg/day as a last series of treatment. Children were given a dose of meglumine of 70 mg/kg/day, in series of treatment with their respective rest period. All patients responded adequately. Once again, we can demonstrate the advantages of the treatment of CLNW with the pentavalent antimony meglumine.


Assuntos
Humanos , Masculino , Adolescente , Adulto , Feminino , Criança , Pessoa de Meia-Idade , Doenças Parasitárias/microbiologia , Leishmaniose Cutânea/diagnóstico , Leishmaniose Cutânea/epidemiologia , Leishmaniose Cutânea/terapia , Doenças Transmissíveis/etiologia , Infectologia , Zona Rural
13.
Rev. nutr ; 16(2): 211-217, abr.-jun. 2003. tab, graf
Artigo em Português | LILACS | ID: lil-341199

RESUMO

O crescente consumo de alimentos de origem vegetal, sejam como fontes protéicas com baixo teor de gordura ou como fontes de fibras, tem acrescido à dieta humana o ácido fítico. Devido à sua carga altamente negativa, o ácido fítico tem sido visto como componente de ação antinutricional capaz de quelar minerais bivalentes, proteínas e amido, podendo comprometer a biodisponibilidade destes nutrientes. No presente estudo investigou-se a influência da adição de ácido fítico à dieta de caseína, em concentrações iguais ou até oito vezes superiores àquelas encontradas no feijão-comum Phaseolus vulgaris, cultivar IAC-Carioca (14,7mg de ácido fítico/g feijão cru), durante período experimental de dez dias, sobre os índices nutricionais Ganho de Peso, Quociente de Eficiência da Dieta, Quociente de Eficiência Protéica Líquida, Digestibilidade Aparente e Digestibilidade Verdadeira. Trinta e seis ratos machos SPF da linhagem Wistar, recém-desmamados, divididos em grupos experimentais com seis ratos cada, foram alimentados com dieta purificada AIN-93G isenta de ácido fítico (Controle) e dietas teste AIN-93G acrescidas de 218, 436, 872 e 1744mg de ácido fítico/kg de dieta (Tratamentos). Os ganhos de peso (g) e os índices de qualidade dietética e protéica não apresentaram diferença estatística (p>0,05), e os valores médios entre os grupos foram: Ganho de Peso: 59,5 ± 5,0g; Quociente de Eficiência da Dieta: 0,39 ± 0,01; Quociente de Eficiência Protéica Líquida: 3,64 ± 0,12; Digestibilidade Aparente: 92,7 ± 1,1 por cento e Digestibilidade Verdadeira: 94,4 ± 0,9 por cento. Os resultados demonstraram que nas condições experimentais utilizadas, o ácido fítico não foi capaz de alterar o valor nutritivo da caseína.


Assuntos
Animais , Masculino , Ratos , Dieta , Ácido Fítico/administração & dosagem , Caseínas/metabolismo , Digestão , Aumento de Peso , Ratos Wistar , Ácido Fítico/metabolismo , Valor Nutritivo
14.
J Comp Physiol B ; 172(7): 577-86, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12355226

RESUMO

The addition of 150 U/ml nystatin to the mucosal surface of isolated skin from larval bullfrogs increases apical membrane permeability and allows a voltage clamp to be applied to the basolateral membrane. With identical Ringer's solutions bathing either side of the tissue the short-circuit current (I(SC)) averaged 7.60+/-0.78 micro A/cm2, and this current could be increased or decreased by imposing a Cl- concentration gradient. Fluctuation analysis of the I(SC) gave power spectra that could be fit with low- and high-frequency Lorentzian functions having corner frequencies of 1.48+/-0.06 Hz and 48.5+/-11.4 Hz, respectively. The Lorentzian plateau was minimal at the lowest I(SC) and increased as the I(SC) became greater in the positive or negative direction. Current-voltage plots with identical Ringer's on either side of the tissue showed a pattern of outward rectification. Cell attached patches of cells isolated from the skin with collagenase-trypsin treatment showed spontaneous channel activity with a conductance of 20.9 pS at a pipette potential, -Vp=20 mV. Current-voltage plots of single channels showed a similar pattern of rectification to that of the intact skin, and partial replacement of Cl- by gluconate in the pipette solution shifted the reversal potential from zero to about 40 mV, which is close to the expected shift of the reversal potential of the chloride current through a Cl- selective ion channel. These results suggest that the basolateral Cl- conductance of the larval skin is mediated by a channel with properties that resemble a volume-sensing outward-rectifier anion channel that has been described in a variety of cell types


Assuntos
Canais de Cloreto/metabolismo , Membranas Intracelulares/metabolismo , Rana catesbeiana/crescimento & desenvolvimento , Rana catesbeiana/metabolismo , Pele/metabolismo , Animais , Canais de Cloreto/fisiologia , Condutividade Elétrica , Epitélio/crescimento & desenvolvimento , Epitélio/metabolismo , Larva/metabolismo , Concentração Osmolar , Técnicas de Patch-Clamp , Pele/crescimento & desenvolvimento
15.
J Exp Biol ; 205(Pt 13): 1943-52, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12077171

RESUMO

The dorsal lingual epithelium from the tongue of the toad Bufo marinus was mounted in an Ussing-type chamber, and the short-circuit current (I(sc)) was measured using a low-noise voltage clamp. With NaCl Ringer bathing the mucosal and serosal surfaces of the isolated tissue, an outwardly directed (mucosa-positive) I(sc) was measured that averaged -10.71+/-0.82 microA cm(-2) (mean +/- S.E.M., N=24) with a resistance of 615+/-152 Omega cm(2) (mean +/- S.E.M., N=10). Substitution of chloride with sulfate as the anion produced no significant change in I(sc). Fluctuation analysis with either NaCl or Na(2)SO(4) Ringer bathing both sides of the tissue revealed a spontaneous Lorentzian component, suggesting that the I(sc) was the result of K(+) secretion through spontaneously fluctuating channels in the apical membrane of the epithelium. This hypothesis was supported by the reversible inhibition of I(sc) by Ba(2+) added to the mucosal Ringer. Analysis of the kinetics of Ba(2+) inhibition of I(sc) indicates that there might be more than one type of K(+) channel carrying the I(sc). This hypothesis was supported by power spectra obtained with a serosa-to-mucosa K(+) gradient, which could be fitted to two Lorentzian components. At present, the K(+) secretory current cannot be localized to taste cells or other cells that might be associated with the secretion of saliva or mucus. Nonetheless, the resulting increase in [K(+)] in fluid bathing the mucosal surface of the tongue could presumably affect the sensitivity of the taste cells. These results contrast with those from the mammalian tongue, in which a mucosa-negative I(sc) results from amiloride-sensitive Na(+) transport.


Assuntos
Bufo marinus/fisiologia , Condutividade Elétrica , Epitélio/fisiologia , Língua/fisiologia , Animais , Ânions/metabolismo , Bário/metabolismo , Eletrofisiologia , Epitélio/efeitos dos fármacos , Técnicas In Vitro , Canais Iônicos/metabolismo , Transporte de Íons/fisiologia , Potenciais da Membrana/fisiologia , Potássio/metabolismo , Bloqueadores dos Canais de Potássio/farmacologia , Quinina/farmacologia , Sódio/metabolismo , Soluções/química
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