MTT

IC50: N/A

MTT (3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide) is a reagent used in the measurement of in vitro cell proliferation.

Tetrazolium salts have been the most widely used tools in cell biology for deternining the metabolic activity of cells ranging from microbial origin to mammalian. Fractionation studies in mammalian cells indicate that NADH, the reduced pyridine nucleotide cofactor, is responsible for most MTT reduction, which is further supported by studies with whole cells.

In vitro: It has been found that MTT reduction was associated not only with mitochondria, but also with the cytoplasm and nonmitochondrial membranes including endosome/lysosome compartment and plasma membrane. The net positive charge on MTT appears to be the predominant factor involved in their cellular uptake through the potential of plasma membrane. However, the second generation tetrazolium dyes (XTT, WST-1 and to some extent, MTS) that form water-soluble formazans and require an intermediate electron acceptor for reduction, are characterised by a net negative charge and therefore are largely cell-impermeable [1].

In vivo: MTT currently is only used for in vitro cell proliferation determination and there is no in vivo study reported.

Clinical trial: N/A

Reference:
[1] Berridge MV,Herst PM,Tan AS.  Tetrazolium dyes as tools in cell biology: new insights into their cellular reduction. Biotechnol Annu Rev.2005;11:127-52.

Backbone assignments for the SPOUT methyltransferase MTT Tm , a knotted protein from Thermotoga maritima.[Pubmed:28284017]

Biomol NMR Assign. 2017 Oct;11(2):151-154.

The SPOUT family of methyltransferase proteins is noted for containing a deep trefoil knot in their defining backbone fold. This unique fold is of high interest for furthering the understanding of knots in proteins. Here, we report the (1)H, (13)C, (15)N assignments for MTT Tm , a canonical member of the SPOUT family. This protein is unique, as it is one of the smallest members of the family, making it an ideal system for probing the unique properties of the knot. Our present work represents the foundation for further studies into the topology of MTT Tm , and understanding how its structure affects both its folding and function.

Correction: Evaluation of Direct Colorimetric MTT Assay for Rapid Detection of Rifampicin and Isoniazid Resistance in Mycobacterium tuberculosis.[Pubmed:28166294]

PLoS One. 2017 Feb 6;12(2):e0171964.

[This corrects the article DOI: 10.1371/journal.pone.0169188.].

Evaluation of antibacterial potential and toxicity of plant volatile compounds using new broth microdilution volatilization method and modified MTT assay.[Pubmed:28223069]

Fitoterapia. 2017 Apr;118:56-62.

With aim to develop effective proof-of-concept approach which can be used in a development of new preparations for the inhalation therapy, we designed a new screening method for simple and rapid simultaneous determination of antibacterial potential of plant volatiles in the liquid and the vapour phase at different concentrations. In addition, EVA (ethylene vinyl acetate) capmat as vapour barrier cover was used as reliable modification of thiazolyl blue tetrazolium bromide (MTT) assay for cytotoxicity testing of volatiles on microtiter plates. Antibacterial activity of carvacrol, cinnamaldehyde, eugenol, 8-hydroxyquinoline, thymol and thymoquinone was determined against Haemophilus influenzae, Staphylococcus aureus, and Streptococcus pneumoniae using new broth microdilution volatilization method. The cytotoxicity of these compounds was evaluated using MTT test in lung fibroblast cells MRC-5. The most effective antibacterial agents were 8-hydroxyquinoline and thymoquinone with the lowest minimum inhibitory concentrations (MICs) ranging from 2 to 128mug/mL, but they also possessed the highest toxicity in lung cell lines with half maximal inhibitory concentration (IC50) values 0.86-2.95mug/mL. The lowest cytotoxicity effect was identified for eugenol with IC50 295.71mug/mL, however this compound produced only weak antibacterial potency with MICs 512-1024mug/mL. The results demonstrate validity of our novel broth microdilution volatilization method, which allows cost and labour effective high-throughput antimicrobial screening of volatile agents without need of special apparatus. In our opinion, this assay can also potentially be used for development of various medicinal, agricultural, and food applications that are based on volatile antimicrobials.

Evaluation of Direct Colorimetric MTT Assay for Rapid Detection of Rifampicin and Isoniazid Resistance in Mycobacterium tuberculosis.[Pubmed:28030634]

PLoS One. 2016 Dec 28;11(12):e0169188.

With the spread of multidrug-resistant tuberculosis (MDR-TB) strains there is an increasing need for new accurate and cost-effective methods for a rapid diagnostic and drug susceptibility testing (DST), particularly in low-income countries where tuberculosis is hyperendemic. A colorimetric assay using 3-(4, 5-dimethylthiazol-2-yl)-2, 5- diphenyltetrazolium bromide (MTT) has been suggested as a promising method for DST, especially to rifampicin. In this study, we standardized and evaluated the MTT assay for a rapid direct detection of rifampicin and isoniazid resistant Mycobacterium tuberculosis strains from sputum specimens using Lowenstein-Jensen (LJ) culture medium as a gold standard. The MTT assay sensitivity, specificity, positive and negative predictive values for rifampicin were 100%, 86%, 100%, 99%, respectively. For isoniazid, the MTT assay had a 100% sensitivity, specificity, positive and negative predictive values. Interestingly, the MTT assay gave interpretable results within two weeks for 94% of the samples compared to 7-14 weeks for LJ media. Overall, an excellent agreement was observed between MTT assay and LJ proportion method (Kappa, 0.91 for rifampicin and 1.00 for isoniazid). In conclusion, the direct colorimetric MTT assay simultaneously detects susceptible and resistant strains of M. tuberculosis within three weeks. It significantly shortens the time required to obtain a DST result and could be a reliable alternative method for rapid detection of drug-resistant TB strains in high-TB-burden resource-limited settings.