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1.
Braz J Biol ; 84: e253180, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36228224

RESUMO

The present work is based on analysis of inhibitory activity of alpha-amylase inhibitor in selected cultivars of Phaseolus vulgaris of Uttarakhand. Fifteen samples were assessed for inhibitory activity of alpha-amylase inhibitor. Significant variations were found in different cultivars. Crude extract of alpha-amylase inhibitor from sample PUR (Purola) have shown maximum inhibitory activity (70.2 ± 0.84). Crude extract of all the cultivars have shown considerable variations in inhibitory activity in the temperature ranging from 20ºC to 100ºC. Based on inhibitory activity and heat stability profile, the alpha amylase inhibitor was purified from PUR cultivar. The purified inhibitor was found to be stable even at 90ºC with an inhibitory activity of 97.20 ±0.09. The molecular weight of purified inhibitor on Native PAGE (Polyacrylamide gel electrophoresis) was found to be 31kd, consisting of two subunits of 17kd and 14kd on SDS-PAGE.


Assuntos
Phaseolus , Misturas Complexas , Cristalografia por Raios X , Phaseolus/química , Proteínas de Plantas/química , alfa-Amilases
2.
Indian J Clin Biochem ; 37(2): 178-184, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35463108

RESUMO

Association of smokeless tobacco (SLT) with oral cancer is well documented. The nitrosamines of SLT are metabolically bioactivated by CYP1A1. Therefore, in this pilot study, we investigated association of CYP1A1 expression with polymorphism, clinicopathological variables and outcome in exclusive SLT chewers. Semiquantitative RT-PCR analysis on RNA isolated from peripheral blood lymphocytes of 65 histopathologically confirmed cases revealed increased CYP1A1 mRNA expression in Msp I (CYP1A1*2A) and Ile/Val (CYP1A1*2C) polymorphic variants. A higher trend of CYP1A1 mRNA levels in invasive and recurrent tumors which also associated with shorter disease free and overall survival was seen. Odds ratio analysis indicated the association of higher CYP1A1 mRNA levels with disease aggressiveness i.e. metastasis and invasion. Study revealed wider oncogenic role of CYP1A1 in oral cancer patients and justifies further studies and analysis in a large cohort.

3.
Exp Oncol ; 40(1): 10-18, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29600984

RESUMO

p53 plays a central role in prevention of normal cell from the development of the malignant phenotype. Somatic alterations (mutations, loss of heterozygosity, deletions) in p53 are a hallmark of most human cancers and cause defects in normal p53 function. However, in the tumors harboring wild-type p53, there are alterations in the regulation of the p53. Thus, understanding why p53 is unable to perform its role as a tumor suppressor in these wild-type tumors is very crucial. Germ-line polymorphisms in p53 are also anticipated to cause measurable disturbance in p53 function. Over-expression as well as polymorphic variants of MDM2 might have effects on cancer development. In addition, degradation of p53 by E6 protein of high risk human papillomavirus is also suggested as one of the mechanisms which attenuate p53 responses in oral carcinogenesis. p53 has also been demonstrated to mediate cellular responses upon various DNA damaging cancer therapies, importantly, apoptosis. These responses have been implicated in an individual's ability to respond to these cancer therapies. Thus, exploring mechanisms by which normal function of p53 is affected in the comprehensive way in oral cancer might aid in the identification of tumor characteristics, prognosis and thus in the development of a new approach to treat the oral cancer.


Assuntos
Neoplasias Bucais/patologia , Proteína Supressora de Tumor p53/metabolismo , Progressão da Doença , Humanos , Índia
4.
Bioresour Technol ; 256: 110-117, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29433045

RESUMO

In the present work, xylan from arecanut husk was extracted using 2 stage alkaline pretreatment process. In first step, biomass was incubated in alkali at different temperatures (25 °C, 50 °C and 65 °C), alkali concentrations (5%, 10%, 15% and 20% w/v), and incubation periods (8 h, 16 h and 24 h) and evaluated for xylan recovery. It was observed that 40-52% of available xylan could be recovered using 10% alkali when incubated for 8-24 h at 65 °C. Subsequently, the alkali pretreatment operating conditions which provided good xylan recovery were processed further using hydrothermal treatment to extract more xylan. For maximum xylan recovery (>90%), best operating conditions were identified when biomass was treated under hydrothermal treatment (1, 1.5 and 2 h) with varying incubation periods (8, 16, 24 h) and alkali concentrations (5%, 10%) using full factorial design. Incubating arecanut husk with 10% w/v NaOH, at 65 °C for a period of 8 h, followed by hydrothermal treatment at 121 °C for 1 h helped recover >94% xylan. In the next step, enzymatic hydrolysis process was optimized to recover maximum XOS (Optimized condition: 50 °C, pH 4 and 10 U enzyme dose). The hydrolysate comprised of xylobiose: 25.0 ±â€¯1.2 g/100 g xylan (∼71% of XOS), xylotriose: 9.2 ±â€¯0.65 g/100 g xylan (26.2% of XOS) and xylotetrose: 0.9 ±â€¯0.04 g/100 g xylan (2% of XOS). The developed process enables to reduce alkali consumption for high recovery of xylan from biomass with relatively higher lignin content for its valorisation into a potential prebiotic oligosaccharide.


Assuntos
Glucuronatos , Oligossacarídeos , Xilanos , Álcalis , Biomassa , Endo-1,4-beta-Xilanases , Hidrólise , Lignina
5.
Environ Monit Assess ; 186(7): 4423-9, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24633786

RESUMO

Phenological documentation and plant invasion are key contemporary issues in the biological sciences. Recognizing this, the present paper describes the phenological stages of an invasive species, Sapium sebiferum (L.) Roxb. A tree of the species was marked, and daily visits were made for recording its phenology. The Biologische Bundesanstalt, Bundessortenamt and CHemical industry (BBCH) scale was used for documenting the same. Of the total ten principal stages, eight were observed in the species. These stages started with bud development (stage 01) in the month of March and ended with leaf fall (stage 97) in the month of December. Descriptions of the phenological stages and their dates are provided in the text. It is hoped that such a phenological scale will be helpful in managing plant invasion.


Assuntos
Monitoramento Ambiental , Espécies Introduzidas , Sapium/fisiologia , Animais , Documentação , Folhas de Planta/crescimento & desenvolvimento , Estações do Ano , Árvores
6.
Oral Dis ; 20(1): 84-93, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23444898

RESUMO

Polymorphic variability in the enzymes involved in biotransformation of tobacco-related pro-carcinogens plays an important role in modulating oral cancer susceptibility. CYP1A1*2A, CYP1A1*2C, GSTM1 and GSTT1 polymorphisms were determined in 122 oral carcinoma cases and 127 controls from Gujarat, West India using PCR-based methods. The results revealed that the polymorphic variants of CYP1A1 gene did not show association towards oral cancer risk. The GSTM1 and GSTT1 null genotypes were found to be over-represented in patients than controls, suggesting a moderate increase in risk of oral cancer. The oral cancer risk was significantly increased in the patients having either alone or concurrent deletion of GSTM1 and GSTT1. The results also suggested significant association between tobacco habits, especially chewing, variant genotypes of CYP1A1, GSTM1 and GSTT1 and oral cancer risk. Our data have provided evidence that GST polymorphism modified the susceptibility to oral cancer and individuals with variant genotypes of the three genes with tobacco habits are at significant risk of developing oral cancer.


Assuntos
Citocromo P-450 CYP1A1/genética , Glutationa Transferase/genética , Neoplasias Bucais/genética , Polimorfismo Genético , Uso de Tabaco/efeitos adversos , Adulto , Feminino , Predisposição Genética para Doença , Humanos , Índia , Masculino
7.
Water Sci Technol ; 68(12): 2521-6, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24355836

RESUMO

The prediction of streamflow is required in many activities associated with the planning and operation of the components of a water resources system. Soft computing techniques have proven to be an efficient alternative to traditional methods for modelling qualitative and quantitative water resource variables such as streamflow, etc. The focus of this paper is to present the development of models using multiple linear regression (MLR), artificial neural network (ANN), fuzzy logic and decision tree algorithms such as M5 and REPTree for predicting the streamflow at Kasol located at the upstream of Bhakra reservoir in Sutlej basin in northern India. The input vector to the various models using different algorithms was derived considering statistical properties such as auto-correlation function, partial auto-correlation and cross-correlation function of the time series. It was found that REPtree model performed well compared to other soft computing techniques such as MLR, ANN, fuzzy logic, and M5P investigated in this study and the results of the REPTree model indicate that the entire range of streamflow values were simulated fairly well. The performance of the naïve persistence model was compared with other models and the requirement of the development of the naïve persistence model was also analysed by persistence index.


Assuntos
Algoritmos , Árvores de Decisões , Lógica Fuzzy , Modelos Teóricos , Redes Neurais de Computação , Movimentos da Água , Índia
8.
Aust Dent J ; 58(3): 293-300, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23981209

RESUMO

BACKGROUND: The aim of this study was to comparatively evaluate the efficacy of the mandibular advancement device (MAD) at 50% (P2) and 75% (P3) of maximum mandibular advancement, relative to maximum intercuspation (P1) subjectively and objectively. METHODS: Eighteen subjects previously diagnosed with obstructive sleep apnoea (OSA) were selected for the study. ESS score, VAS score, soft palate angle, MP-H distance, S-H distance, a C4 -H distance, a Pu -p Pu distance and total pharyngeal area were calculated at P1, P2 and P3 positions with the help of an adjustable MAD. The results were statistically analysed. RESULTS: ESS score, VAS score, soft palate angle, MP-H distance, S-H distance and radius of curvature of airway at P2 and P3 were significantly lower compared to P1, but there was no significant difference between P2 and P3. CONCLUSIONS: The MAD produced significant improvement in objective signs and subjective symptoms at both 50% and 75% of the maximum mandibular protrusion positions at comparable comfort levels. Therefore, MAD may be given at 50% of maximum advancement in order to reduce dental or temporomandibular joint disturbances.


Assuntos
Arcada Osseodentária/anatomia & histologia , Avanço Mandibular/métodos , Apneia Obstrutiva do Sono/terapia , Adulto , Idoso , Análise de Variância , Cefalometria/métodos , Feminino , Humanos , Masculino , Avanço Mandibular/instrumentação , Pessoa de Meia-Idade , Palato Mole/anatomia & histologia , Faringe/anatomia & histologia , Projetos Piloto , Estudos Prospectivos , Apneia Obstrutiva do Sono/etiologia
9.
Artigo em Inglês | MEDLINE | ID: mdl-23747380

RESUMO

The fluorescence decay time of Fullerenes C60 and C70 in pure form as well as in mixture with Coumarin C440 and Quinizarine dyes are studied. Results indicate that the decay of pure fullerenes is constant throughout the solute concentration and it is also independent of excitation wavelength, whereas in the case of mixture with dyes different behavior is noticed. We have also calculated the Stern-Volmer quenching constant and optical gain of both the fullerenes from which it is found that the optical gain is positive for Fullerene C70 only in a very narrow range of concentration.


Assuntos
Fulerenos/química , Absorção , Cumarínicos/química , Transferência de Energia , Espectrometria de Fluorescência , Fatores de Tempo
10.
Neuroscience ; 240: 117-28, 2013 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-23485812

RESUMO

Identification of markers of enteric neurons has contributed substantially to our understanding of the development, normal physiology, and pathology of the gut. Previously identified markers of the enteric nervous system can be used to label all or most neuronal structures or for examining individual cells by labeling just the nucleus or cell body. Most of these markers are excellent but have some limitations. Transmembrane protein 100 (TMEM100) is a gene at locus 17q32 encoding a 134-amino acid protein with two hypothetical transmembrane domains. TMEM100 expression has not been reported in adult mammalian tissues but does appear in the ventral neural tube of embryonic mice and plays a role in signaling pathways associated with development of the enteric nervous system. We showed that TMEM100 messenger RNA is expressed in the gastrointestinal tract and demonstrated that TMEM100 is a membrane-associated protein. Furthermore TMEM100 immunoreactivity was restricted to enteric neurons and vascular tissue in the muscularis propria of all regions of the mouse and human gastrointestinal tract. TMEM100 immunoreactivity colocalized with labeling for the pan-neuronal marker protein gene product 9.5 (PGP9.5) but not with the glial marker S100ß or Kit, a marker of interstitial cells of Cajal. The signaling molecule, bone morphogenetic protein (BMP) 4, was also expressed in enteric neurons of the human colon and co-localized with TMEM100. TMEM100 is also expressed in neuronal cell bodies and fibers in the mouse brain and dorsal root ganglia. We conclude that TMEM100 is a novel, membrane-associated marker for enteric nerves and is as effective as PGP9.5 for identifying neuronal structures in the gastrointestinal tract. The expression of TMEM100 in the enteric nervous system may reflect a role in the development and differentiation of cells through a transforming growth factor ß, BMP or related signaling pathway.


Assuntos
Sistema Nervoso Entérico/metabolismo , Trato Gastrointestinal/metabolismo , Proteínas de Membrana/metabolismo , Animais , Especificidade de Anticorpos , Proteína Morfogenética Óssea 4/metabolismo , Linhagem Celular Transformada , Sistema Nervoso Entérico/citologia , Humanos , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Fatores de Crescimento Neural/metabolismo , Neuroglia/metabolismo , Neurônios/metabolismo , Proteínas Proto-Oncogênicas c-kit/metabolismo , RNA Mensageiro/metabolismo , Subunidade beta da Proteína Ligante de Cálcio S100 , Proteínas S100/metabolismo , Transfecção , Ubiquitina Tiolesterase/metabolismo
11.
Environ Monit Assess ; 185(7): 6129-53, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23196408

RESUMO

Recognizing the array of effects that invasive alien species have, documenting their status from biodiversity rich regions has been much emphasized. Lack of such studies is a major limitation that hampers proper management of alien species. The present paper, therefore, documents the alien flora of the Indian Himalayan state of Himachal Pradesh (HP) based on data obtained from literature and herbarium records. The alien flora of HP comprises of 497 species belonging to 85 families. Majority of them belong to family Asteraceae (59 species), followed by Poaceae (47 species) and Fabaceae (43 species). Amongst the genera, Ipomoea (9 species), Eucalyptus and Euphorbia (7 species each) are the most predominant. Herbs constitute the majority (i.e., 73%) of alien species and a large percentage of them (i.e., 22.94%) have South America as their native region. Further, of the total alien species, 248 are intentional introductions and majority (31% species) have been introduced for ornamental purposes. It was revealed that 34% species have naturalized while 29% species have become invasive. Today, in addition to human-disturbed landscapes, alien species have also been reported from dense forests. Himalaya being a biodiversity hotspot and HP being a bio-rich Himalayan state, it is hoped that this inventory and assessment of alien flora will help in designing informed management and monitoring strategies against problematic plant invasions in the state.


Assuntos
Biodiversidade , Ecossistema , Espécies Introduzidas/estatística & dados numéricos , Plantas/classificação , Meio Ambiente , Índia
12.
J Environ Manage ; 107: 1-18, 2012 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-22579769

RESUMO

Arsenic contamination in ground water, used for drinking purpose, has been envisaged as a problem of global concern. However, arsenic contamination of ground water in parts of South East Asia is assuming greater proportions and posing a serious threat to the health of millions of people. A variety of treatment technologies based on oxidation, co-precipitation, adsorption, ion exchange and membrane process are available for the removal of arsenic from ground water. However, question remains regarding the efficiency and applicability/appropriateness of the technologies, particularly because of low influent arsenic concentration and differences in source water composition. Some of these methods are quite simple, but the disadvantage associated with them is that they produce large amounts of toxic sludge, which needs further treatment before disposal into the environment. Besides, the system must be economically viable and socially acceptable. In this paper an attempt has been made to review and update the recent advances made in the technological development in arsenic removal technologies to explore the potential of those advances to address the problem of arsenic contamination in South East Asia.


Assuntos
Arsênio/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Sudeste Asiático
13.
J Nat Med ; 66(1): 1-7, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21625946

RESUMO

This study reports an appreciable yield of podophyllotoxin (PDT) in P. hexandrum plants grown ex situ under polyhouse conditions of a temperate locale. The PDT content of below-ground parts was affected by both plant age and growth period. However, only the effect of plant age on PDT content was significant. Thus, the highest amounts of PDT were recorded in the below-ground parts of 2-year-old plants harvested during the late-growth period (LGP). High total soluble sugars in the below-ground parts during the early growth period (EGP) and the highest nitrate and nitrate reductase in the leaves of 2-year-old plants during the peak-growth period (PGP) indicated higher mobilization and assimilation of starch and nitrate. Probably the surplus carbon and nitrogen gained during the PGP were diverted from aerial parts to below-ground parts during the LGP and in turn contributed to the synthesis of higher amounts of PDT. This study shows that commercial cultivation of P. hexandrum is possible under ex situ temperate conditions.


Assuntos
Podofilotoxina/biossíntese , Podophyllum/metabolismo , Biomassa , Carboidratos/biossíntese , Carbono/metabolismo , Espécies em Perigo de Extinção , Nitrogênio/metabolismo , Componentes Aéreos da Planta/metabolismo , Raízes de Plantas/metabolismo , Podofilotoxina/isolamento & purificação , Estações do Ano
14.
Nat Prod Res ; 25(13): 1271-7, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21854174

RESUMO

Volatile oil composition of the leaves of Rhododendron anthopogon (Ericaceae) growing wild in alpine Western Himalaya was studied using different extraction techniques including SC-CO(2) extraction and hydrodistillation (HD). Results from different extraction methodologies were compared with headspace analysis (HS) and evaluated for the effectiveness of techniques in characterisation of various terpene categories and to assess their influence on the yield and composition of volatiles. Variability in constituents and in quantitative yields was observed. The results varied with different extraction methods. A total of 27 constituents in SC-CO(2) extraction, 31 in HD and 17 in HS analysis were identified. Constituents in SC-CO(2) and HD oils were identified by gas chromatography mass spectrometry analysis. SC-CO(2) extraction was carried out at 40°C and 140 bar pressure and the oil represented by major constituents as ß-caryophyllene (5.96%), α-humulene (4.06%) and p-menthadiene-2,9-diol (7.28%); in HD, oil limonene (11.26%), ß-caryophyllene (11.62%), α-humulene (7.22%), and E-nerolidol (5.83%) dominated the oil and in HS analysis, limonene (24.14%), γ-terpinene (40.73%), α-terpinene (4.92%), ß-phellandrene (3.44%) and ß-ocimene (7.15%) were present as major constituents.


Assuntos
Dióxido de Carbono/química , Óleos de Plantas/química , Rhododendron/química , Volatilização , Cromatografia Gasosa-Espectrometria de Massas
15.
Artigo em Inglês | MEDLINE | ID: mdl-20869302

RESUMO

The interaction between Coumarin C440 with Fullerene C60 has been studied by fluorescence and time resolved spectroscopic techniques. The Coumarin C440-Fullerene C60 pair shows Forster's resonance energy transfer (FRET) from Coumarin C440 (donor) to Fullerenes C60 (acceptor). The FRET efficiency of this pair increases with the increase of the acceptor concentration. The critical energy transfer distance (R0) at which transfer efficiency is 50% is found to be 34Ǻ. Stern-Volmer plot indicates static as well as dynamic quenching. However, the FRET studies show highest efficiency at the critical stage of dimer formation.


Assuntos
Cumarínicos/química , Transferência Ressonante de Energia de Fluorescência/métodos , Fulerenos/química , Dimerização , Modelos Biológicos , Modelos Moleculares , Espectrometria de Fluorescência
16.
Artigo em Inglês | MEDLINE | ID: mdl-18930436

RESUMO

The energy transfer studies in the case of ternary dye mixture [Stilbene-420 (donor)+Coumarin-540 (intermediator)+Nile Blue (acceptor)] have been done and discussed through optical gain characteristics at various acceptor concentrations under nitrogen laser excitation. The concentration of the other two dyes were kept constant. It is observed that the concentration of the acceptor dye plays a very critical role in energy transfer dye laser (ETDL) as small change in its concentration varies the intensity of the laser output in the red region by large amount. Also, the highest laser output in the red region is obtained when the concentration of the acceptor dye is slightly higher than that of the intermediator dye. The present studies are helpful in deciding the optimum concentration of the acceptor dye to be used in ternary dye mixture for maximum gain and tuning range. The ternary dye mixture under study provides an ETDL tuning range up to 700 nm.


Assuntos
Cumarínicos/farmacologia , Transferência de Energia/efeitos dos fármacos , Oxazinas/farmacologia , Estilbenos/farmacologia , Absorciometria de Fóton/instrumentação , Cumarínicos/química , Relação Dose-Resposta a Droga , Combinação de Medicamentos , Corantes Fluorescentes/química , Corantes Fluorescentes/farmacologia , Lasers de Gás , Modelos Biológicos , Concentração Osmolar , Oxazinas/química , Estilbenos/química
17.
Fitoterapia ; 79(6): 401-18, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18639617

RESUMO

Ginkgo biloba has been existing on earth since 200 million years and is considered as a "living fossil". It is among the most sold medicinal plants in the world. A number of secondary metabolites representing terpenoids, polyphenols, allyl phenols, organic acids, carbohydrates, fatty acids and lipids, inorganic salts and amino acids have been isolated from the plant. However, the main bioactive constituents are terpene trilactones and flavonoid glycosides which are considered responsible for the pharmacological activities of its standardized leaf extract. Scattered information is available on the extraction and analysis of these pharmacologically important constituents which have been compiled in the present review.


Assuntos
Ginkgo biloba , Fitoterapia , Flavonoides/química , Flavonoides/isolamento & purificação , Ginkgo biloba/anatomia & histologia , Ginkgo biloba/química , Ginkgo biloba/classificação , Ginkgo biloba/fisiologia , Glicosídeos/química , Glicosídeos/isolamento & purificação , Estrutura Molecular , Fitoterapia/economia , Plantas Medicinais
18.
J Assoc Physicians India ; 51: 828-9, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-14651153
19.
Indian J Med Res ; 115: 184-8, 2002 May.
Artigo em Inglês | MEDLINE | ID: mdl-12362557

RESUMO

BACKGROUND & OBJECTIVES: Anaerobic conditions are frequently encountered by pathogens invading the gastrointestinal tract due to low/limiting oxygen conditions prevalent in the small intestine. This anaerobic stress has been suggested to enhance the virulence of gut pathogens. In the present study, we examined the effect of anaerobiosis on the virulence of Salmonella Typhi, a Gram negative bacteria which invades through the gut mucosa and is responsible for typhoid fever. METHODS: Salmonella Typhi (ty2) was cultured in aerobic and anaerobic conditions to compare its virulence by rabbit ileal loop assay, hydrophobicity assay, expression of outer membrane proteins (OMPs) and antioxidant enzymes assay. RESULTS: Anaerobically grown S. Typhi showed significantly higher cell surface hydrophobicity as compared to aerobic bacteria. In vivo toxin production by rabbit ileal loop assay also showed significantly higher fluid accumulation with anaerobic S. Typhi. Expression of OMPs in anaerobic S. Typhi showed a distinct induction of five outer membrane proteins. We observed that exposure of anaerobic S. Typhi to aerobic conditions induced significantly higher level of antioxidant enzymes like superoxide dismutase (SOD) and catalase. INTERPRETATION & CONCLUSION: Our results suggest that exposure of S. Typhi to anaerobic conditions enhances its virulence.


Assuntos
Salmonella typhi/patogenicidade , Anaerobiose , Animais , Proteínas da Membrana Bacteriana Externa/metabolismo , Catalase/metabolismo , Enterotoxinas/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Íleo/microbiologia , Masculino , Oxigênio/metabolismo , Coelhos , Superóxido Dismutase/metabolismo , Virulência
20.
J Cell Biol ; 154(3): 535-47, 2001 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-11481344

RESUMO

Sphingolipids (SLs) are plasma membrane constituents in eukaryotic cells which play important roles in a wide variety of cellular functions. However, little is known about the mechanisms of their internalization from the plasma membrane or subsequent intracellular targeting. We have begun to study these issues in human skin fibroblasts using fluorescent SL analogues. Using selective endocytic inhibitors and dominant negative constructs of dynamin and epidermal growth factor receptor pathway substrate clone 15, we found that analogues of lactosylceramide and globoside were internalized almost exclusively by a clathrin-independent ("caveolar-like") mechanism, whereas an analogue of sphingomyelin was taken up approximately equally by clathrin-dependent and -independent pathways. We also showed that the Golgi targeting of SL analogues internalized via the caveolar-like pathway was selectively perturbed by elevated intracellular cholesterol, demonstrating the existence of two discrete Golgi targeting pathways. Studies using SL-binding toxins internalized via clathrin-dependent or -independent mechanisms confirmed that endogenous SLs follow the same two pathways. These findings (a) provide a direct demonstration of differential SLs sorting into early endosomes in living cells, (b) provide a "vital marker" for endosomes derived from caveolar-like endocytosis, and (c) identify two independent pathways for lipid transport from the plasma membrane to the Golgi apparatus in human skin fibroblasts.


Assuntos
Antígenos CD , Membrana Celular/metabolismo , Clatrina/metabolismo , Globosídeos/farmacocinética , Complexo de Golgi/metabolismo , Lactosilceramidas/farmacocinética , Proteínas Adaptadoras de Transdução de Sinal , Compostos de Boro/farmacocinética , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Caveolina 1 , Caveolinas/metabolismo , Células Cultivadas , Dinaminas , Endocitose/fisiologia , Endossomos/metabolismo , Fibroblastos/citologia , Corantes Fluorescentes/farmacocinética , GTP Fosfo-Hidrolases/genética , GTP Fosfo-Hidrolases/metabolismo , Gangliosidoses/metabolismo , Proteínas de Fluorescência Verde , Humanos , Indicadores e Reagentes/farmacocinética , Peptídeos e Proteínas de Sinalização Intracelular , Proteínas Luminescentes/farmacocinética , Mutagênese/fisiologia , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Transporte Proteico/fisiologia , Pele/citologia
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