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1.
Mol Plant Pathol ; 22(2): 271-283, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33301200

RESUMO

Pectobacterium carotovorum has an incomplete Entner-Doudoroff (ED) pathway, including enzyme 2-keto-3-deoxy-6-phosphogluconate aldolase (Eda) but lacking phosphogluconate dehydratase (Edd), while P. atrosepticum (Pba) has a complete pathway. To understand the role of the ED pathway in Pectobacterium infection, mutants of these two key enzymes, Δeda and Δedd, were constructed in Pba SCRI1039. Δeda exhibited significant decreased virulence on potato tubers and colonization in planta and was greatly attenuated in pectinase activity and the ability to use pectin breakdown products, including polygalacturonic acid (PGA) and galacturonic acid. These reduced phenotypes were restored following complementation with an external vector expressing eda. Quantitative reverse transcription PCR analysis revealed that expression of the pectinase genes pelA, pelC, pehN, pelW, and pmeB in Δeda cultured in pyruvate, with or without PGA, was significantly reduced compared to the wild type, while genes for virulence regulators (kdgR, hexR, hexA, and rsmA) remained unchanged. However, Δedd showed similar phenotypes to the wild type. To our knowledge, this is the first demonstration that disruption of eda has a feedback effect on inhibiting pectin degradation and that Eda is involved in building the arsenal of pectinases needed during infection by Pectobacterium.


Assuntos
Aldeído Liases/metabolismo , Pectobacterium/metabolismo , Hidroliases/metabolismo , Redes e Vias Metabólicas , Pectinas/metabolismo , Pectobacterium/enzimologia , Pectobacterium/patogenicidade , Solanum tuberosum/microbiologia , Virulência
2.
J Agric Food Chem ; 68(37): 10109-10117, 2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32829629

RESUMO

Linalool is abundant in tea leaves and contributes greatly to tea aroma. The two isomers of linalool, (R)-linalool and (S)-linalool, exist in tea leaves. Our study found that (R)-linalool was the minor isomer in nine of Camellia sinensis var. sinensis cultivars. The (R)-linalool synthase of tea plant CsRLIS was identified subsequently. It is a chloroplast-located protein and specifically catalyzes the formation of (R)-linalool in vitro and in vivo. CsRLIS was observed to be a stress-responsive gene and caused the accumulation of internal (R)-linalool during oolong tea manufacture, mechanical wounding, and insect attack. Further study demonstrated that the catalytic efficiency of CsRLIS was much lower than that of (S)-linalool synthase CsSLIS, which might explain the lower (R)-linalool proportion in C. sinensis var. sinensis cultivars. The relative expression levels of CsRLIS and CsSLIS may also affect the (R)-linalool proportions among C. sinensis var. sinensis cultivars. This information will help us understand differential distributions of chiral aroma compounds in tea.


Assuntos
Monoterpenos Acíclicos/química , Camellia sinensis/enzimologia , Hidroliases/metabolismo , Proteínas de Plantas/metabolismo , Monoterpenos Acíclicos/metabolismo , Biocatálise , Camellia sinensis/química , Camellia sinensis/genética , Camellia sinensis/metabolismo , Cloroplastos/enzimologia , Cloroplastos/genética , Cloroplastos/metabolismo , Hidroliases/química , Hidroliases/genética , Odorantes/análise , Proteínas de Plantas/química , Proteínas de Plantas/genética , Estereoisomerismo , Chá/química
3.
Protein Sci ; 29(3): 711-722, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31811683

RESUMO

Galactarate dehydratase (GarD) is the first enzyme in the galactarate/glucarate pathway and catalyzes the dehydration of galactarate to 3-keto-5-dehydroxygalactarate. This protein is known to increase colonization fitness of intestinal pathogens in antibiotic-treated mice and to promote bacterial survival during stress. The galactarate/glucarate pathway is widespread in bacteria, but not in humans, and thus could be a target to develop new inhibitors for use in combination therapy to combat antibiotic resistance. The structure of almost all the enzymes of the galactarate/glucarate pathway were solved previously, except for GarD, for which only the structure of the N-terminal domain was determined previously. Herein, we report the first crystal structure of full-length GarD solved using a seleno-methoionine derivative revealing a new protein fold. The protein consists of three domains, each presenting a novel twist as compared to their distant homologs. GarD in the crystal structure forms dimers and each monomer consists of three domains. The N-terminal domain is comprised of a ß-clip fold, connected to the second domain by a long unstructured linker. The second domain serves as a dimerization interface between two monomers. The C-terminal domain forms an unusual variant of a Rossmann fold with a crossover and is built around a seven-stranded parallel ß-sheet supported by nine α-helices. A metal binding site in the C-terminal domain is occupied by Ca2+ . The activity of GarD was corroborated by the production of 5-keto-4-deoxy-D-glucarate under reducing conditions and in the presence of iron. Thus, GarD is an unusual enolase with a novel protein fold never previously seen in this class of enzymes.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/enzimologia , Hidroliases/química , Fosfopiruvato Hidratase/química , Cristalografia por Raios X , Hidroliases/metabolismo , Testes de Sensibilidade Microbiana , Modelos Moleculares , Estrutura Molecular , Fosfopiruvato Hidratase/metabolismo , Dobramento de Proteína/efeitos dos fármacos
4.
Plant Physiol Biochem ; 142: 43-52, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31272034

RESUMO

Yarrow (Achillea millefolium) is a medicinal plant from the Asteracea which biosynthesize different secondary metabolites especially terpenes and phenylpropanoids. To improve our understanding of the regulatory mechanisms behind the biosynthesis of these compounds we analyzed the expression of some genes associated with the biosynthesis of terpenes and phenylpropanoids in different tissues and in response to trans-cinnamic acid (tCA) as an inhibitor of PAL activity. Isolation and expression analysis of DXR, GPPS, PAL and CHS genes together with linalool synthase (LIS) as monoterpene synthase was conducted in different developmental stages of leaves, flowers and in response to trans-cinnamic acid (tCA). Differential expression of these genes observed in different tissues. tCA up-regulated the biosynthetic genes of monterpenes and down-regulated the biosynthetic genes of phenylpropanoids. Gene expression analysis in intact leaves and leaves without glandular trichomes showed that DXR, LIS, PAL and CHS are highly expressed in glandular trichomes while GPPS expressed ubiquitously. Analysis of essential oils composition showed that sesquiterpenes and monoterpenes are main compounds; in which from 57 identified compounds the highest were germacreneD (% 11.5), guaiol (%10.38), spatulenol (%8.73) and caryophyllene oxide (%7.48).


Assuntos
Achillea/genética , Achillea/metabolismo , Fenilpropionatos/metabolismo , Proteínas de Plantas/genética , Terpenos/metabolismo , Achillea/química , Achillea/efeitos dos fármacos , Aciltransferases/genética , Aciltransferases/metabolismo , Aldose-Cetose Isomerases/genética , Aldose-Cetose Isomerases/metabolismo , Vias Biossintéticas , Cinamatos/farmacologia , Farnesiltranstransferase/genética , Farnesiltranstransferase/metabolismo , Flores/genética , Flores/crescimento & desenvolvimento , Cromatografia Gasosa-Espectrometria de Massas , Regulação da Expressão Gênica de Plantas , Hidroliases/genética , Hidroliases/metabolismo , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Tricomas/genética , Tricomas/metabolismo
5.
Methods ; 156: 110-120, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30391513

RESUMO

Among different RNA modifications, the helix 69 (H69) region of the bacterial ribosomal RNA (rRNA) contains three pseudouridines (Ψs). H69 is functionally important due to its location in the heart of the ribosome. Several structural and functional studies have shown the importance of Ψ modifications in influencing the H69 conformation as well as maintaining key interactions in the ribosome during protein synthesis. Therefore, a need exists to understand the influence of modified nucleosides on conformational dynamics of the ribosome under solution conditions that mimic the cellular environment. In this review on chemical probing, we provide detailed protocols for the use of dimethyl sulfate (DMS) to examine H69 conformational states and the influence of Ψ modifications under varying solution conditions in the context of both ribosomal subunits and full ribosomes. The use of DMS footprinting to study the binding of aminoglycosides to the H69 region of bacterial rRNA as a potential antibiotic target will also be discussed. As highlighted in this work, DMS probing and footprinting are versatile techniques that can be used to gain important insight into RNA local structure and RNA-ligand interactions, respectively.


Assuntos
Escherichia coli/genética , Impressão Molecular/métodos , Pseudouridina/química , RNA Ribossômico 16S/química , RNA Ribossômico 23S/química , Compostos de Anilina/química , Antibacterianos/farmacologia , Fracionamento Celular/métodos , DNA Complementar/biossíntese , DNA Complementar/química , DNA Complementar/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Gentamicinas/farmacologia , Hidroliases/genética , Hidroliases/metabolismo , Ligantes , Cloreto de Magnésio/farmacologia , Neomicina/farmacologia , Conformação de Ácido Nucleico , Fatores de Terminação de Peptídeos/genética , Fatores de Terminação de Peptídeos/metabolismo , Pseudouridina/genética , Pseudouridina/metabolismo , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , RNA Ribossômico 23S/genética , RNA Ribossômico 23S/metabolismo , Transcrição Reversa , Subunidades Ribossômicas Maiores de Bactérias/química , Subunidades Ribossômicas Maiores de Bactérias/efeitos dos fármacos , Subunidades Ribossômicas Maiores de Bactérias/genética , Subunidades Ribossômicas Maiores de Bactérias/metabolismo , Subunidades Ribossômicas Menores de Bactérias/química , Subunidades Ribossômicas Menores de Bactérias/efeitos dos fármacos , Subunidades Ribossômicas Menores de Bactérias/genética , Subunidades Ribossômicas Menores de Bactérias/metabolismo , Ribossomos/química , Ribossomos/efeitos dos fármacos , Ribossomos/genética , Ribossomos/metabolismo , Ésteres do Ácido Sulfúrico/química
6.
J Am Chem Soc ; 140(27): 8487-8496, 2018 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-29894625

RESUMO

We present a series of QM/MM calculations aimed at understanding the mechanism of the biological dehydration of glycerol. Strikingly and unusually, this process is catalyzed by two different radical enzymes, one of which is a coenzyme-B12-dependent enzyme and the other which is a coenzyme-B12-independent enzyme. We show that glycerol dehydration in the presence of the coenzyme-B12-dependent enzyme proceeds via a 1,2-OH shift, which benefits from a significant catalytic reduction in the barrier. In contrast, the same reaction in the presence of the coenzyme-B12-independent enzyme is unlikely to involve the 1,2-OH shift; instead, a strong preference for direct loss of water from a radical intermediate is indicated. We show that this preference, and ultimately the evolution of such enzymes, is strongly linked with the reactivities of the species responsible for abstracting a hydrogen atom from the substrate. It appears that the hydrogen-reabstraction step involving the product-related radical is fundamental to the mechanistic preference. The unconventional 1,2-OH shift seems to be required to generate a product-related radical of sufficient reactivity to cleave the relatively inactive C-H bond arising from the B12 cofactor. In the absence of B12, it is the relatively weak S-H bond of a cysteine residue that must be homolyzed. Such a transformation is much less demanding, and its inclusion apparently enables a simpler overall dehydration mechanism.


Assuntos
Clostridium butyricum/enzimologia , Gliceraldeído/análogos & derivados , Glicerol/metabolismo , Hidroliases/metabolismo , Klebsiella pneumoniae/enzimologia , Propano/metabolismo , Vitamina B 12/metabolismo , Biocatálise , Clostridium butyricum/química , Clostridium butyricum/metabolismo , Gliceraldeído/química , Gliceraldeído/metabolismo , Glicerol/química , Klebsiella pneumoniae/química , Klebsiella pneumoniae/metabolismo , Modelos Moleculares , Propano/química , Vitamina B 12/química
7.
Nat Commun ; 8: 16040, 2017 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-28699638

RESUMO

Branched-chain aminotransferases (BCAT) are enzymes that initiate the catabolism of branched-chain amino acids (BCAA), such as leucine, thereby providing macromolecule precursors; however, the function of BCATs in macrophages is unknown. Here we show that BCAT1 is the predominant BCAT isoform in human primary macrophages. We identify ERG240 as a leucine analogue that blocks BCAT1 activity. Selective inhibition of BCAT1 activity results in decreased oxygen consumption and glycolysis. This decrease is associated with reduced IRG1 levels and itaconate synthesis, suggesting involvement of BCAA catabolism through the IRG1/itaconate axis within the tricarboxylic acid cycle in activated macrophages. ERG240 suppresses production of IRG1 and itaconate in mice and contributes to a less proinflammatory transcriptome signature. Oral administration of ERG240 reduces the severity of collagen-induced arthritis in mice and crescentic glomerulonephritis in rats, in part by decreasing macrophage infiltration. These results establish a regulatory role for BCAT1 in macrophage function with therapeutic implications for inflammatory conditions.


Assuntos
Ciclo do Ácido Cítrico , Leucina/análogos & derivados , Leucina/farmacologia , Macrófagos Peritoneais/metabolismo , Transaminases/metabolismo , Animais , Artrite Experimental/tratamento farmacológico , Artrite Reumatoide/tratamento farmacológico , Avaliação Pré-Clínica de Medicamentos , Glomerulonefrite/tratamento farmacológico , Humanos , Hidroliases/metabolismo , Macrófagos Peritoneais/efeitos dos fármacos , Masculino , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Ratos , Succinatos/metabolismo , Transaminases/antagonistas & inibidores
8.
Appl Environ Microbiol ; 83(9)2017 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-28235876

RESUMO

Oleate hydratases (OhyAs) catalyze the conversion of unsaturated fatty acids to 10-hydroxy fatty acids, which are used as precursors of important industrial compounds, including lactones and ω-hydroxycarboxylic and α,ω-dicarboxylic acids. The genes encoding OhyA and a putative fatty acid hydratase in Stenotrophomonas maltophilia were identified by genomic analysis. The putative fatty acid hydratase was purified and identified as an oleate hydratase (OhyA2) based on its substrate specificity. The activity of OhyA2 as a holoenzyme was not affected by adding cofactors, whereas the activity of the original oleate hydratase (OhyA1) showed an increase. Thus, all characterized OhyAs were categorized as either OhyA1 or OhyA2 based on the activities of holoenzymes upon adding cofactors, which were determined by the type of the fourth conserved amino acid of flavin adenine dinucleotide (FAD)-binding motif. The hydration activities of S. maltophilia OhyA2 toward unsaturated fatty acids, including oleic acid, palmitoleic acid, linoleic acid, α-linolenic acid, and γ-linolenic acid, were greater than those of OhyA1. Moreover, the specific activity of S. maltophilia OhyA2 toward unsaturated fatty acids, with the exception of γ-linolenic acid, was the highest among all reported OhyAs.IMPORTANCE All characterized OhyAs were categorized as OhyA1s or OhyA2s based on the different properties of the reported and newly identified holo-OhyAs in S. maltophilia upon the addition of cofactors. OhyA2s showed higher activities toward polyunsaturated fatty acids (PUFAs), including linoleic acid, α-linolenic acid, and γ-linolenic acid, than those of OhyA1s. This suggests that OhyA2s can be used more effectively to convert plant oils to 10-hydroxy fatty acids because plant oils contain not only oleic acid but also PUFAs. The hydration activity of the newly identified OhyA2 from S. maltophilia toward oleic acid was the highest among the activity levels reported so far. Therefore, this enzyme is an efficient biocatalyst for the conversion of plant oils to 10-hydroxy fatty acids, which can be further converted to important industrial materials.


Assuntos
Ácidos Graxos Insaturados/metabolismo , Hidroliases/metabolismo , Ácido Oleico/metabolismo , Stenotrophomonas maltophilia/enzimologia , Coenzimas/metabolismo , Hidroliases/isolamento & purificação , Cinética , Especificidade por Substrato
9.
Biotechnol Bioeng ; 114(1): 74-82, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27474883

RESUMO

Hydroxy fatty acids are used as precursors of lactones and dicarboxylic acids, as starting materials of polymers, and as additives in coatings and paintings. Stenotrophomonas nitritireducens efficiently converts cis-9 polyunsaturated fatty acids (PUFAs) to 10-hydroxy fatty acids. However, gene encoding enzyme involved in this conversion has not been identified to date. We purified a putative fatty acid double-bond hydratase from S. nitritireducens by ultrafiltration and HiPrep DEAE FF and Resource Q ion exchange chromatographies. Peptide sequences of the purified enzyme were obtained by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) analysis. Sequence of the partial gene encoding this putative fatty acid double-bond hydratase was determined by degenerate polymerase chain reaction (PCR) based on the peptide sequences. The remaining gene sequence was identified by rapid amplification of cDNA ends using cDNA of S. nitritireducens as a template, and the full-length gene was cloned subsequently. The expressed enzyme was identified as an oleate hydratase by determining its kinetic parameters toward unsaturated fatty acids. S. nitritireducens oleate hydratase showed higher activity toward PUFAs compared with other available oleate hydratases. This suggested that the enzyme could be used effectively to convert plant oils to 10-hydroxy fatty acids because these oils contained unsaturated fatty acids such as oleic acid (OA) and linoleic acid (LA) and PUFAs such as α-linolenic acid and/or γ-linolenic acid. The enzyme converted soybean oil and perilla seed oil hydrolyzates containing 10 mM total unsaturated fatty acids, including OA, LA, and ALA, to 8.87 and 8.70 mM total 10-hydroxy fatty acids, respectively, in 240 min. To our knowledge, this is the first study on the biotechnological conversion of PUFA-containing oils to hydroxy fatty acids. Biotechnol. Bioeng. 2017;114: 74-82. © 2016 Wiley Periodicals, Inc.


Assuntos
Proteínas de Bactérias/genética , Clonagem Molecular/métodos , Hidroliases/genética , Ácido Oleico/metabolismo , Proteínas Recombinantes/genética , Stenotrophomonas/enzimologia , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Escherichia coli/genética , Ácidos Graxos Insaturados/análise , Ácidos Graxos Insaturados/metabolismo , Hidroliases/química , Hidroliases/metabolismo , Ácido Oleico/química , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Stenotrophomonas/genética , Especificidade por Substrato
10.
Mol Med Rep ; 14(6): 5677-5684, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27878271

RESUMO

Estrogen (E2) has been demonstrated to possess protective effects from hypoglycemic toxicity, particularly in the pancreas. In the central nervous system, several brain regions, such as the hypothalamus, are highly vulnerable to hypoglycemic injuries that may lead to seizures, coma, and mortality. The present study performed a novel in vitro assay of hypoglycemic injury to hypothalamic cells, and is the first study, to the best of our knowledge, to demonstrate that E2 protects hypothalamic cells from hypoglycemic toxicity. The toxic effects of hypoglycemia on hypothalamic cells in vitro was determined by performing cell counts, together with MTT and lactate dehydrogenase assays, using the N38 murine hypothalamic cell line. Following 24 and 48 h in hypoglycemic conditions, a 60 and 75% reduction in cell number and mitochondrial function was observed, which reached 80 and ~100% by 72 and 96 h, respectively. E2 treatment prevented the hypoglycemia­induced loss in cell number and mitochondrial toxicity at 24 and 48 h. However at 72 and 96 h of hypoglycemic conditions, the neuroprotective effects of E2 on cell number or mitochondrial function was not significant or not present at all. In order to determine whether E2 exerted its effects through the AKT signaling pathway, the expression of proline­rich AKT substrate of 40 kDa (PRAS40) was analyzed. No alterations in PRAS40 expression were observed when N38 cells were exposed to hypoglycemic shock. From the biochemical and molecular data obtained, the authors speculated that E2 exhibits neuroprotective effects against hypoglycemic shock in hypothalamic cells, which dissipates with time. Despite demonstrating no significant effect on total AKT/PRS40 activity, it is possible that E2 may mediate these neuroprotective effects by upregulating the phosphorylated­AKT/pPRAS40 signaling pathway. The present study presented, to the best of our knowledge, the first in vitro model for hypoglycemic toxicity to hypothalamic cells, and provided evidence to suggest that E2 may protect hypothalamic cells from the damaging effects of hypoglycemia.


Assuntos
Estrogênios/farmacologia , Hipoglicemia/metabolismo , Hipotálamo/citologia , Hipotálamo/metabolismo , Fármacos Neuroprotetores/farmacologia , Animais , Glicemia , Sobrevivência Celular/efeitos dos fármacos , Hidroliases/metabolismo , Camundongos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Fosfoproteínas/genética , Fosfoproteínas/metabolismo
11.
Biotechnol Lett ; 38(5): 817-23, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26758723

RESUMO

OBJECTIVE: To produce δ-decalactone from linoleic acid by one-pot reaction using linoleate 13-hydratase with supplementation with whole Yarrowia lipolytica cells. RESULTS: Whole Y. lipolytica cells at 25 g l(-1) produced1.9 g l(-1) δ-decalactone from 7.5 g 13-hydroxy-9(Z)-octadecenoic acid l(-1) at pH 7.5 and 30 °C for 21 h. Linoleate 13-hydratase from Lactobacillus acidophilus at 3.5 g l(-1) with supplementation with 25 g Y. lipolytica cells l(-1) in one pot at 3 h produced 1.9 g l(-1) δ-decalactone from 10 g linoleic acid l(-1) via 13-hydroxy-9(Z)-octadecenoic acid intermediate at pH 7.5 and 30°C after 18 h, with a molar conversion yield of 31 % and productivity of 106 mg l(-1) h(-1). CONCLUSION: To the best of our knowledge, this is the first production of δ-decalactone using unsaturated fatty acid.


Assuntos
Proteínas de Bactérias/metabolismo , Hidroliases/metabolismo , Lactobacillus acidophilus/enzimologia , Lactonas/metabolismo , Ácido Linoleico/metabolismo , Pironas/metabolismo , Yarrowia/metabolismo , Concentração de Íons de Hidrogênio , Temperatura
12.
Mol Med Rep ; 11(2): 968-74, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25371265

RESUMO

Arsenic sulfide (As4S4) is the main component of realgar, which is widely used in traditional Chinese medicine. Previous studies have shown the beneficial effects of As4S4 in the treatment of hematological malignant diseases, however, its effects on solid tumors have yet to be fully elucidated. The current study aimed to explore the anti­cancer effect and the mechanism of As4S4 on solid tumors in vitro and in vivo. Cells from four human solid tumor cell lines, including the MKN45 gastric cancer cell line, the A375 malignant melanoma cell line, the 8898 pancreatic carcinoma cell line and the HepG2 hepatocellular carcinoma cell line, were treated with As4S4 in vitro, using the L02 embryonic liver cells as a control. The efficacy of As4S4 was assessed in vivo using mice implanted with Lewis lung carcinoma cells. The results of the current study demonstrated that As4S4 significantly inhibited the proliferation of solid tumor cells in a dose­ and time­dependent manner, but produced a less pronounced effect on L02 cells. Additionally, As4S4 was observed to induce apoptosis (including morphological changes and an enhanced sub­G1 population), which was accompanied by the activation of caspase­3 and ­9. Furthermore, treatment with As4S4 significantly inhibited the growth of implanted tumors in mice. These results suggest that As4S4 possesses potent in vitro and in vivo antitumor activity via the induction of cell apoptosis.


Assuntos
Antineoplásicos/farmacologia , Arsenicais/farmacologia , Sulfetos/farmacologia , Animais , Apoptose/efeitos dos fármacos , Caspase 3/genética , Caspase 3/metabolismo , Caspase 9/genética , Caspase 9/metabolismo , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Fase G2/efeitos dos fármacos , Células Hep G2 , Humanos , Hidroliases/metabolismo , Interleucina-2/sangue , Masculino , Melanoma/tratamento farmacológico , Camundongos , Camundongos Endogâmicos C57BL , Ensaios Antitumorais Modelo de Xenoenxerto
13.
Eur J Nutr ; 54(4): 509-22, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25112514

RESUMO

PURPOSE: Human islet amyloid polypeptide (hIAPP) aggregation is linked to loss of pancreatic beta cells in type 2 diabetes, in part due to oxidative stress. Currently, little is known about the effects of selenium-enriched Spirulina on beta cells with the presence of hIAPP. In this study, INS-1E rat insulinoma cells were used as a model to evaluate in vitro protective effects of Se-enriched Spirulina extract (Se-SE) against hIAPP-induced cell death, as well as the underlying mechanisms. METHODS: Flow cytometric analysis was used to evaluate cell apoptosis, mitochondrial membrane potential (ΔΨm) and ROS generation. Caspase activity was measured using a fluorometric method. Western blotting was applied to detect protein expression. RESULTS: Our results showed that exposure of INS-1E cells to hIAPP resulted in cell viability loss, LDH release and appearance of sub-G peak. However, cytotoxicity of hIAPP was significantly attenuated by co-treatment with Se-SE. Se-SE also inhibited hIAPP-induced activation of caspase-3, -8 and -9. Additionally, hIAPP-induced accumulation of ROS and superoxide was suppressed by co-treatment with Se-SE. Moreover, Se-SE was able to prevent hIAPP-induced depletion of ΔΨm and intracellular ATP, reduction in mitochondrial mass, changes in the expression of Bcl-2 family members, release of mitochondrial apoptogenic factors. Furthermore, hIAPP-mediated AKT inhibition was restored by co-treatment with Se-SE. CONCLUSION: Our results showed that Se-SE protects INS-1E cells from hIAPP-induced cell death through preventing ROS overproduction, mitochondrial dysfunction and modulating PI3K/AKT pathway.


Assuntos
Apoptose/efeitos dos fármacos , Células Secretoras de Insulina/efeitos dos fármacos , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Selênio/farmacologia , Spirulina , Animais , Caspase 3/metabolismo , Caspase 8/metabolismo , Caspase 9/metabolismo , Linhagem Celular , Humanos , Hidroliases/metabolismo , Potencial da Membrana Mitocondrial , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase , Substâncias Protetoras/farmacologia , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Proteína X Associada a bcl-2/metabolismo
14.
J Toxicol Sci ; 39(2): 179-90, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24646698

RESUMO

The development of hepatitis is associated with the infiltration and activation of immune cells in liver. N-3 polyunsaturated fatty acids (n-3 PUFAs) rich fish oil (FO) is used to prevent and treat inflammatory diseases. But, the effects of dietary FO on autoimmune hepatitis remain largely unknown. In this study, Concanavalin A (Con A) induced hepatitis was used to evaluate the actions of dietary FO. Unexpectedly, 2-week FO treatment had not shown any protection, on the contrary, exacerbated liver injury in this hepatitis model. The levels of alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) statistically increased from 10,501 ± 2,154 and 30,394 ± 2,420 in low fat diet (LFD)/Con A group to 17,579 ± 693 and 49,439 ± 4,628 in FO/Con A group. Simultaneously, FO diet induced more necrotic liver tissues and apoptotic hepatocytes, and up-regulated the hepatic expression of TNF-α and IFN-γ after Con A challenge. Interestingly, FO promoted severe liver injury was accompanied by decreasing the percentage of CD4⁺ T cell, NK1.1⁺ cells and CD8⁺ T cells in CD45⁺ liver non-parenchymal hepatic cells (NPCs) through inducing apoptosis. Further experiments declared 2-week FO diet intake firstly increased the proportion of CD11b⁺Gr-1(hi) neutrophils in liver, but then dramatically expanded CD11b⁺Gr-1(int) inflammatory monocytes population after Con A administration. Collectively, our study indicated that high FO intake not only aggravated liver injury, but also altered the population of immune cells in liver. Thus, these results indicated that when dietary FO was used to benefit health in autoimmune diseases, its potential risks of side effect also need paying close attention.


Assuntos
Apoptose , Doença Hepática Induzida por Substâncias e Drogas/patologia , Concanavalina A/farmacologia , Ácidos Graxos Ômega-3/efeitos adversos , Óleos de Peixe/efeitos adversos , Hepatite Autoimune/patologia , Hepatócitos/patologia , Fígado/imunologia , Alanina Transaminase/metabolismo , Animais , Apoptose/imunologia , Antígeno CD11b , Linfócitos T CD4-Positivos/patologia , Linfócitos T CD8-Positivos/patologia , Doença Hepática Induzida por Substâncias e Drogas/imunologia , Suplementos Nutricionais/efeitos adversos , Modelos Animais de Doenças , Óleos de Peixe/química , Hepatite Autoimune/imunologia , Hepatócitos/efeitos dos fármacos , Hepatócitos/imunologia , Hidroliases/metabolismo , Interferon gama/metabolismo , Células Matadoras Naturais/patologia , Antígenos Comuns de Leucócito , Fígado/citologia , Fígado/metabolismo , Fígado/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neutrófilos , Fator de Necrose Tumoral alfa/metabolismo
15.
Antioxid Redox Signal ; 20(2): 191-203, 2014 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-23795780

RESUMO

AIMS: Glutathione peroxidase (GPX) mimic ebselen and superoxide dismutase (SOD) mimic copper diisopropylsalicylate (CuDIPs) were used to rescue impaired glucose-stimulated insulin secretion (GSIS) in islets of GPX1 and(or) SOD1-knockout mice. RESULTS: Ebselen improved GSIS in islets of all four tested genotypes. The rescue in the GPX1 knockout resulted from a coordinated transcriptional regulation of four key GSIS regulators and was mediated by the peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α)-mediated signaling pathways. In contrast, CuDIPs improved GSIS only in the SOD1 knockout and suppressed gene expression of the PGC-1α pathway. INNOVATION: Islets from the GPX1 and(or) SOD1 knockout mice provided metabolically controlled intracellular hydrogen peroxide (H2O2) and superoxide conditions for the present study to avoid confounding effects. Bioinformatics analyses of gene promoters and expression profiles guided the search for upstream signaling pathways to link the ebselen-initiated H2O2 scavenging to downstream key events of GSIS. The RNA interference was applied to prove PGC-1α as the main mediator for that link. CONCLUSION: Our study revealed a novel metabolic use and clinical potential of ebselen in rescuing GSIS in the GPX1-deficient islets and mice, along with distinct differences between the GPX and SOD mimics in this regard. These findings highlight the necessities and opportunities of discretional applications of various antioxidant enzyme mimics in treating insulin secretion disorders. REBOUND TRACK: This work was rejected during standard peer review and rescued by Rebound Peer Review (Antioxid Redox Signal 16: 293-296, 2012) with the following serving as open reviewers: Regina Brigelius-Flohe, Vadim Gladyshev, Dexing Hou, and Holger Steinbrenner.


Assuntos
Azóis/farmacologia , Glucose/metabolismo , Glutationa Peroxidase/metabolismo , Insulina/metabolismo , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , Compostos Organosselênicos/farmacologia , Animais , Glucoquinase/metabolismo , Teste de Tolerância a Glucose , Transportador de Glucose Tipo 2/metabolismo , Glutationa Peroxidase/genética , Glutationa Redutase/metabolismo , Proteínas de Homeodomínio/metabolismo , Hidroliases/metabolismo , Secreção de Insulina , Canais Iônicos/metabolismo , Isoindóis , Masculino , Camundongos , Camundongos Knockout , Proteínas Mitocondriais/metabolismo , Mimetismo Molecular , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , Espécies Reativas de Oxigênio/metabolismo , Selênio/farmacologia , Transdução de Sinais/efeitos dos fármacos , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Transativadores/metabolismo , Fatores de Transcrição/metabolismo , Proteína Desacopladora 2
16.
Appl Microbiol Biotechnol ; 98(2): 519-32, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24270894

RESUMO

Pectins are complex branched polysaccharides present in primary cell walls. As a distinctive feature, they contain high amount of partly methyl-esterified galacturonic acid and low amount of rhamnose and carry arabinose and galactose as major neutral sugars. Due to their structural complexity, they are modifiable by many different enzymes, including hydrolases, lyases, and esterases. Their peculiar structure is the origin of their physicochemical properties. Among others, their remarkable gelling properties make them a key additive for food industries. Pectin-degrading enzymes and -modifying enzymes may be used in a wide variety of applications to modulate pectin properties or produce pectin derivatives and oligosaccharides with functional as well as nutritional interests. This paper reviews the scientific information available on pectin structure, pectin-modifying enzymes, and the use of enzymes to produce pectin with controlled structure or pectin-derived oligosaccharides, with functional or nutritional interesting properties.


Assuntos
Esterases/metabolismo , Hidroliases/metabolismo , Pectinas/metabolismo , Aditivos Alimentares/metabolismo , Oligossacarídeos/metabolismo , Pectinas/química
17.
PLoS One ; 8(10): e77624, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24147038

RESUMO

Alzheimer's disease (AD) is characterized by progressive dysfunction of memory and higher cognitive functions with abnormal accumulation of extracellular amyloid plaques and intracellular neurofibrillary tangles throughout cortical and limbic brain regions. At present no curative treatment is available, and research focuses on drugs for slowing disease progression or providing prophylaxis. Withania somnifera (WS) also known as 'ashwagandha' is used widely in Ayurvedic medicine as a nerve tonic and memory enhancer. However, there is a paucity of data on the potential neuroprotective effects of W.somnifera against ß-Amyloid (1-42)-induced neuropathogenesis. In the present study, we have tested the neuroprotective effects of methanol:Chloroform (3:1) extract of ashwagandha against ß-amyloid induced toxicity and HIV-1Ba-L (clade B) infection using a human neuronal SK-N-MC cell line. Our results showed that ß-amyloid induced cytotoxic effects in SK-N-MC cells as shown by decreased cell growth when tested individually. Also, confocal microscopic analysis showed decreased spine density, loss of spines and decreased dendrite diameter, total dendrite and spine area in clade B infected SK-N-MC cells compared to uninfected cells. However, when ashwagandha was added to ß-amyloid treated and HIV-1 infected samples, the toxic effects were neutralized. Further, the MTT cell viability assays and the peroxisome proliferator-activated receptor-γ (PPARγ) levels supported these observations indicating the neuroprotective effect of WS root extract against ß-amyloid and HIV-1Ba-L (clade B) induced neuro-pathogenesis.


Assuntos
Peptídeos beta-Amiloides/toxicidade , Fármacos Neuroprotetores/farmacologia , Fragmentos de Peptídeos/toxicidade , Extratos Vegetais/farmacologia , Withania/química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Dendritos/efeitos dos fármacos , Infecções por HIV/complicações , Humanos , Hidroliases/metabolismo , Espectrometria de Massas , Doenças do Sistema Nervoso/etiologia , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/química , PPAR gama/metabolismo , Extratos Vegetais/química
18.
ChemSusChem ; 6(11): 2149-56, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23934656

RESUMO

Polymers based on renewable resources have become increasingly important. The natural functionalization of fats and oils enables an easy access to interesting monomeric building blocks, which in turn transform the derivative biopolymers into high-performance materials. Unfortunately, interesting building blocks of medium-chain length are difficult to obtain by traditional chemical means. Herein, a biotechnological pathway is established that could provide an environmentally suitable and sustainable alternative. A multiple enzyme two-step one-pot process efficiently catalyzed by a coupled 9S-lipoxygenase (St-LOX1, Solanum tuberosum) and 9/13-hydroperoxide lyase (Cm-9/13HPL, Cucumis melo) cascade reaction is proposed as a potential route for the conversion of linoleic acid into 9-oxononanoic acid, which is a precursor for biopolymers. Lipoxygenase catalyzes the insertion of oxygen into linoleic acid through a radical mechanism to give 9S-hydroperoxy-octadecadienoic acid (9S-HPODE) as a cascade intermediate, which is subsequently cleaved by the action of Cm-9/13HPL. This one-pot process afforded a yield of 73 % combined with high selectivity. The best reaction performance was achieved when lipoxygenase and hydroperoxide lyase were applied in a successive rather than a simultaneous manner. Green leaf volatiles, which are desired flavor and fragrance products, are formed as by-products in this reaction cascade. Furthermore, we have investigated the enantioselectivity of 9/13-HPLs, which exhibited a strong preference for 9S-HPODE over 9R-HPODE.


Assuntos
Biopolímeros/química , Ácidos Graxos/síntese química , Cetoácidos/síntese química , Biocatálise , Técnicas de Química Sintética , Cucumis melo/enzimologia , Ácidos Graxos/química , Hidroliases/metabolismo , Concentração de Íons de Hidrogênio , Cetoácidos/química , Ácido Linoleico/química , Lipoxigenase/metabolismo , Solanum tuberosum/enzimologia , Estereoisomerismo , Especificidade por Substrato
19.
Int J Mol Sci ; 14(7): 15141-66, 2013 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-23880863

RESUMO

Biotechnological approaches using genetic modifications such as homologous gene overexpression can be used to decode gene functions under well-defined circumstances. However, only the recording of the resulting phenotypes allows inferences about the impact of the modification on the organisms' evolutionary, ecological or economic performance. We here compare a potato wild-type cell line with two genetically engineered cell cultures homologously overexpressing Pathogenesis Related Protein 10a (pr-10a). A detailed analysis of the relative gene-expression patterns of pr-10a and its regulators sebf and pti4 over time provides insights into the molecular response of heterotrophic cells to distinct osmotic and salt-stress conditions. Furthermore, this system serves as an exemplar for the tracing of respiration kinetics as a faster and more sensitive alternative to the laborious and time-consuming recording of growth curves. The utility and characteristics of the resulting data type and the requirements for its appropriate analysis are figured out. It is demonstrated how this novel type of phenotypic information together with the gene-expression-data provides valuable insights into the effect of genetic modifications on the behaviour of cells on both the molecular and the macroscopic level.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Proteínas Nucleares/metabolismo , Proteínas de Plantas/metabolismo , Solanum tuberosum/metabolismo , Proteínas de Ligação a DNA/genética , Expressão Gênica , Genótipo , Hidroliases/genética , Hidroliases/metabolismo , Proteínas Nucleares/genética , Pressão Osmótica , Fenótipo , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Regiões Promotoras Genéticas , Solanum tuberosum/genética
20.
Asian Pac J Trop Med ; 6(7): 525-31, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23768823

RESUMO

OBJECTIVE: To study the potential ameliorating properties of cardamom Elettaria cardamomum (E. cardamomum) L. Maton against pan masala induced damage in lung of male Swiss mice. METHODS: The experimental animals were divided into 3 groups (control, pan masala treated group and pan masala with cardamom treated group) to evaluate pan masala toxicity. The observations were substantiated with profound changes in the lung tissue as revealed in the histologic and transmission electron microscopic examinations. RESULTS: Lung of pan masala treated group showed adenocarcinoma, edema, and inflammation with increased activity of acid phosphatase, alkaline phosphatase, and lactate dehydrogenase. The deleterious effects were seen to be less in cardamom treated group and the enzymatic activity also decreased significantly (P<0.05) in the ameliorating group. CONCLUSIONS: Thus, the present experiment exciting results are observed when cardamom is supplemented with pan masala, or when given alone.


Assuntos
Lesão Pulmonar Aguda/prevenção & controle , Elettaria , Fitoterapia/métodos , Extratos Vegetais/farmacologia , Especiarias/toxicidade , Tabaco sem Fumaça/toxicidade , Fosfatase Ácida/metabolismo , Lesão Pulmonar Aguda/induzido quimicamente , Lesão Pulmonar Aguda/patologia , Fosfatase Alcalina/metabolismo , Animais , Hidroliases/metabolismo , Masculino , Camundongos
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