Tetrazolium Salts and Formazans

Altman, F. P.

doi:10.1016/s0079-6336(76)80015-0

Cited by 353 publications

(206 citation statements)

References 111 publications

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“…reduced by reducing sugars such as lactose in alkaline pH (Altman, 1976). In addition, the Maillard reaction product changes to a reactive species like an alkoxy radical at alkaline pH (Sakurai & Tsuchiya,1 988).…”

Section: Methodsmentioning

confidence: 99%

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Reduction of Tetrazolium Salt XTT with UHT-Treated Milk: Its Relationship with the Extent of Heat-Treatment and Storage Conditions.

Ukeda

Goto

Sawamura

et al. 1995

FSTI

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Agricu/ture, Kochi University, Monobe B-200, Nankoku Co., Ltd., 1-2l-3, Sakae-cho, Higashimurayama, Tokyo 783, Japa n 189, Japan UHT-treated milk reduced 3'-{1-L(phenylamino)-carbonylJ-3,1~tetrazolium}-bis(4hmethoxy-6-nitro)benzenesulfonic acid hydrate (XTT). The reducibility was caused by the Maillard reaction intermediate between milk protein and lactose. First, the assay procedure of the XTT reduction was optimized using the heated model solution containing casein and lactose and UHT-treated milk. When the XTT reduction assay was applied to two kinds of UHT-treated milks under optimum conditions, the ability of each milk sample to reduce XTT significantly reflected the extent of the heat treatment as well as the evaluation method using the hydroxymethylfurfural (HMF) value. In contrast to the HMF value, the ability of UHT-treated milk gradually decreased depending upon the storage period and temperature. These results suggest not only that the present XTT assay is applicable to estimate the extent of heat treatment but also that the reducibility of the milk sample heat-treated under a given condition can serve to estimate the storage period if the storage temperature is known or vice versa. The method is much simpler (only mixing of the XTT solution containing menadione with milk sample) and quicker (about 20 min) with a satisfactory reproducibility than the conventional methods to estimate the extent of the Maillard reaction such as the lactulose or HMF determination.

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Section: Methodsmentioning

confidence: 99%

“…Tetrazolium salts have proven useful as an indicator of reducing systems like the electron transport system (ETS) of microorganisms and also in a number of enzymatic assays (Altman, 1976). Bacteria with an actlve ETS reduce these redox dyes from a water soluble tetrazolium salt to a colored, water-insoluble formazan product.…”

mentioning

confidence: 99%

Reduction of Tetrazolium Salt XTT with UHT-Treated Milk: Its Relationship with the Extent of Heat-Treatment and Storage Conditions.

Ukeda

Goto

Sawamura

et al. 1995

FSTI

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“…Cell viability was determined by counting viable cells after a ten-min treatment with bisbenzimide (0.8 Ag/mL), Triton X-100 (0.005%) or with the MTT assay (the conversion of the yellow tetrazolium salt [3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, MTT] to the purple formazan dye depends upon the mitochondrial activity [3,53]). The MTT assay was performed on neurons in N5 medium 1% HS, with MTT (0.5 mg/mL) for 4 h in a humidified atmosphere at 37 -C, 5% CO 2 .…”

Section: Cell Viabilitymentioning

confidence: 99%

IGF-I protects cortical neurons against ceramide-induced apoptosis via activation of the PI-3K/Akt and ERK pathways; is this protection independent of CREB and Bcl-2?

Willaime‐Morawek

Arbez

Mariani

et al. 2005

Molecular Brain Research

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Current understanding of IGF-I-mediated neuroprotection implies the activation of phosphatidylinositol-3-kinase (PI-3K), which leads to the activation of Akt/Protein Kinase B. In non-neuronal cells, Akt phosphorylates and activates the transcription factor CREB, implicated in the transcription of the anti-apoptotic bcl-2 gene. This paper further analyses the anti-apoptotic IGF-I action in neurons. We show that IGF-I protects cortical neurons against ceramide-induced apoptosis. Ceramide decreases Akt phosphorylation during apoptotic process whereas a simultaneous treatment with IGF-I increases Akt phosphorylation. Analysis of the signal transduction pathways revealed that IGF-I induces CREB phosphorylation via PI-3K and ERK, whereas simultaneous ceramide and IGF-I treatment decreases CREB phosphorylation. Although an overexpression of Bcl-2 protects cortical neurons against ceramide-induced apoptosis, our data indicate that the Bcl-2 protein level is not modulated during IGF-I, ceramide and/or LY294002 treatment. In consequence, we demonstrated that IGF protects neurons against ceramide-induced apoptosis and that IGF-I protection involves the PI-3K/Akt and ERK pathways; this protection may be independent of CREB and Bcl-2. D

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“…For further confirmation, cytological measurements of reduction of tetrazolium salts were carried out. These compounds are positively charged yellow dyes and enter the cell where they are reduced to a lipid-insoluble purple formazan by cleavage of the tetrazolium ring due to the activity of dehydrogenase enzymes in the cytosol and the mitochondria (Altman, 1976). Tetrazolium salts are used for cell respiration measurement (Stowe et al, 1995) or more generally as indicators of active cell metabolism (Bernas and Dobrucki, 1999).…”

Section: Measurement Of Fungal Respiratory Activitymentioning

confidence: 99%

Root Factors Induce Mitochondrial-Related Gene Expression and Fungal Respiration during the Developmental Switch from Asymbiosis to Presymbiosis in the Arbuscular Mycorrhizal FungusGigaspora rosea

et al. 2003

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During spore germination, arbuscular mycorrhizal (AM) fungi show limited hyphal development in the absence of a host plant (asymbiotic). In the presence of root exudates, they switch to a new developmental stage (presymbiotic) characterized by extensive hyphal branching. Presymbiotic branching of the AM fungus Gigaspora rosea was induced in liquid medium by a semipurified exudate fraction from carrot (Daucus carota) root organ cultures. Changes in RNA accumulation patterns were monitored by differential display analysis. Differentially appearing cDNA fragments were cloned and further analyzed. Five cDNA fragments could be identified that show induced RNA accumulation 1 h after the addition of root exudate. Sequence similarities of two fragments to mammalian Nco4 and mitochondrial rRNA genes suggested that root exudates could influence fungal respiratory activity. To support this hypothesis, additional putative mitochondrial related-genes were shown to be induced by root exudates. These genes were identified after subtractive hybridization and putatively encode a pyruvate carboxylase and a mitochondrial ADP/ATP translocase. The gene GrosPyc1 for the pyruvate carboxylase was studied in more detail by cloning a cDNA and by quantifying its RNA accumulation. The hypothesis that respiratory activity of AM fungi is stimulated by root exudates was confirmed by physiological and cytological analyses in G. rosea and Glomus intraradices. Oxygen consumption and reducing activity of both fungi was induced after 3 and 2 h of exposition with the root factor, respectively, and the first respiration activation was detected in G. intraradices after approximately 90 min. In addition, changes in mitochondrial morphology, orientation, and overall biomass were detected in G. rosea after 4 h. In summary, the root-exuded factor rapidly induces the expression of certain fungal genes and, in turn, fungal respiratory activity before intense branching. This defines the developmental switch from asymbiosis to presymbiosis, first by gene activation (0.5-1 h), subsequently on the physiological level (1.5-3 h), and finally as a morphological response (after 5 h).Arbuscular mycorrhizal (AM) fungi are obligate biotrophic root symbionts that cannot be propagated in pure culture. Therefore, they are difficult to study, and analyses concerning the structure and the function of their genes are rare and mainly based on PCR techniques (Franken and Requena, 2001). Establishment of the symbiosis after spore germination includes hyphal branching, appressorium development after contacting the root, symbiotic colonization of the cortex, formation of the intracellular arbuscules, and, concomitantly, production of a sporulative extraradical mycelium (Bianciotto and Bonfante, 1998; Smith and Read, 1997). These developmental stages presumably require molecular communication between the fungus and the plant. Signals should be exchanged between the partners, leading to stagespecific patterns of gene expression. The corresponding gene products in turn would be re...

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Tetrazolium Salts and Formazans

Cited by 353 publications

References 111 publications

Reduction of Tetrazolium Salt XTT with UHT-Treated Milk: Its Relationship with the Extent of Heat-Treatment and Storage Conditions.

Reduction of Tetrazolium Salt XTT with UHT-Treated Milk: Its Relationship with the Extent of Heat-Treatment and Storage Conditions.

IGF-I protects cortical neurons against ceramide-induced apoptosis via activation of the PI-3K/Akt and ERK pathways; is this protection independent of CREB and Bcl-2?

Root Factors Induce Mitochondrial-Related Gene Expression and Fungal Respiration during the Developmental Switch from Asymbiosis to Presymbiosis in the Arbuscular Mycorrhizal FungusGigaspora rosea

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