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This work aimed to verify if there is a temporal effect on the viability of black oat seeds under natural conditions after harvesting, under burial. The treatments were arranged in a bifactorial scheme, with five black oat genotypes and eight exhumation periods (90; 180; 270; 360; 450; 540; 630 and 720 days after burial), distributed in four repetitions of one hundred seeds buried at 10 cm deep. After each exhumation, seeds separation and count, those that did not germinate, did not rot, or were predated were considered as whole seeds, which underwent a process of asepsis and disinfection to verify viability through the germination test and vigor through the tetrazolium test (live seeds). The genotypes showed a decreasing percentage of seeds over time, Agro Planalto showed the lowest percentage at 360 days after burial, Agro Esteio at 450 days, Agro Coxilha, Agro Quaraí and Agro Zebu at 540 days. The percentage of live seeds differed between the genotypes only in the third period of exhumation (270 days after burial), the lowest percentages of live seeds were identified in the genotypes Agro Esteio and Agro Planalto at 360 days after burial, in Agro Coxilha and Agro Quaraí at 450 days and Agro Zebu at 540 days. Black oat seeds remain viable in the soil for a period of 450 days after burial. [ABSTRACT FROM AUTHOR]

Iron-binding strategies in anticancer drug design target the key role of iron in cancer growth. The incorporation of a quinoline moiety in the design of tetrazolium-based prochelators facilitates their intracellular reduction/activation to iron-binding formazans. The new prochelators are antiproliferative at submicromolar levels, induce apoptosis and cell cycle arrest, and impact iron signaling in cancer cells. [ABSTRACT FROM AUTHOR]

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a human pathogenic virus that encodes for a helicase (SC2Hel) that is essential for viral replication. SC2Hel has the ability to unravel dsRNA or dsDNA in an NTP-dependent manner from the 5′ to 3′ directionality. The standard helicase assay from studies involving SARS-CoV and SARS-CoV-2 have relied on the concept of fluorescence resonance energy transfer. Adding to the collection of helicase assays, herein, we have developed a novel tetrazolium-based colorimetric assay system for the detection of ADP that is produced via SC2Hel activity. This SC2Hel assay combines three enzyme-coupled steps involving the ADP-dependent Thermococcus litoralis glucokinase (TlGlcK), Leuconostoc mesenteroides glucose-6-phosphate dehydrogenase (LmG6PDH), and Clostridium kluyveri diaphorase (CkDIA). Iodonitrotetrazolium chloride (INT), a colorimetric tetrazolium reagent, was used in the final step of the assay that converted into INT-formazan during reduction. INT-formazan in the assay's buffered solution at pH 7.6 exhibited an intense colorimetric response at a wavelength maximum of 505 nm. The assay exhibited excellent performance characteristics as it revealed a Z' factor of 0.87 and it has the potential to be further adopted into high-throughput screening studies for therapeutic drug discovery research. [ABSTRACT FROM AUTHOR]

This study evaluated aspects of the pollen viability of the species Myrceugenia euosma (O. Berg) D. Legrand and Siphoneugena reitzii D. Legrand (Myrtaceae), both native trees with ornamental, medicinal and industrial potential. The study used different concentrations of sucrose to determine pollen viability in vitro and through colorimetric tests with specific dyes (Lugol, carmine acetic, and tetrazolium chloride – TTC – 0.1 and 0.05%). The two species also had their pollen stored for 30 and 90 days in freezers, refrigerators, and natural environments to check the best method for preserving their viability. The results showed that the highest average germination of M. euosma pollen was in a culture medium containing 30% sucrose. After 30 and 90 days of storage, pollen viability was significantly reduced, having preserved part of its potential only in the freezer. The pollen of S. reitzii had a higher average germination rate in a medium with 20% sucrose, but also showed a reduction in viability after 30 and 90 days of storage. The colorimetric tests showed that the pollen of both species responded to the dyes. However, the viability of Lugol and carmine acetic was considered to be overestimated in relation to the in vitro germination tests. Tetrazolium at 0.1% proved to be an alternative for checking the viability of S. reitzii pollen. It can be concluded that different concentrations of sucrose affect germination, and that storing pollen at a low temperature can preserve some of its viability in the short term.

Biochars have received much attention as efficient adsorbents for water pollutants. Besides, the chemical treatment of biochars performed to increase the adsorption capacity usually causes secondary chemical pollution and increases the cost of the process. The biomass feedstock utilised in biochar preparation impacts significantly the surface properties and adsorption capacity. Thus, the need to prepare new biochars from new feedstock with potentially high uptake capacities. Herein, we prepared new biochar (POBC) from Platanus occidentalis waste leaves (POL), which was utilised for the ultrasonic-aided adsorption of bromophenol blue (BRB) and thiazolyl blue tetrazolium bromide (TTB). The FTIR, SEM, EDX, TGA, BET, pHpzc, and elemental characterisations of POBC revealed potent surface characteristics desirable for efficient dye adsorption. An increase in the surface area from 14.31 m2/g to 31.94 m2/g and the pore volume from 0.0214 cm3/g to 0.0326 cm3/g was obtained after the conversion of the POL to POBC. Besides, the SEM images of POBC revealed a highly porous surface structure of the adsorbent. The Freundlich and pseudo-second-order model presented the best fit to the isotherm and kinetics based on the high coefficient of determination (R2 > 0.9) and low sum square errors (SSE < 0.31). The heterogeneous surface nature of POBC was inferred from the independent-oriented site model. The monolayer adsorption capacity of 45.03 mg/g and 48.8 mg/g were obtained for BRB and TTB, respectively. Thermodynamics showed an endothermic, feasible, and random uptake, and POBC displayed efficient potentials to be reused. The obtained results revealed that novel POBC is an efficient low-cost biochar with high adsorption capacity for dyes. [ABSTRACT FROM AUTHOR]

The objective of this study is to perform a bibliographic review of the published scientific material on the use of tetrazolium test and plant bioregulator in seeds of Eugenia stipitata, as well as in the emergence of its seedlings. Research on this species could reveal and record its production potential. E. stipitata is a fruit species native to the Amazon belonging to the Myrtaceae family. Undoubtedly, a prominent species potentially provides fruits with great benefits for human health and new alternatives for production systems. According to the bibliographic survey, the emergence of E. stipitata seedlings can exceed 180 days after sowing, while in the tetrazolium test the results can be obtained between 6 and 30 hours. In relation to seed physical and physiological dormancy, the plant bioregulator has potential to promote emergence of vigorous seeds and seedlings. Thus, the tetrazolium test can be an alternative to determine viability of Eugenia stipitata seeds. Different priming periods and concentrations of the tetrazolium salt solution are required for seeds of the genus Eugenia. Using the plant bioregulator can accelerate the emergence of seedlings of the genus Eugenia. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Ciencias Agroveterinarias is the property of Revista de Ciencias Agroveterinarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of BIOAGRO is the property of Revista BIOAGRO and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The imidazolate-bridged diCu(II) complex [Cu2(dien)2(μ-Im)]3+ (Im = imidazolate, dien = diethylenetriamine) was encapsulated in mesoporous spherical silica particles (MSSP) with retention of the morphology and mesostructure of the guest-free silica particles. This hybrid material catalyzes the dismutation of superoxide efficiently, with second-order catalytic rate constant of 8.28 × 107 M−1 s−1, obtained from the nitro blue tetrazolium photoreduction inhibition superoxide dismutase assay, at pH = 7.8. The small silica channels of MSSP (wp = 2.7 nm) enhance the distortion of the Cu(II) local environment compared to mesoporous silicas with wider pores and ensure the two metal moieties of the reduced catalyst remain in close proximity to react with superoxide. These two combined effects increase the SOD activity of the hybrid material ten times over the free catalyst. The small channel size is also relevant for the salpn derived functional SOD mimic [CuZn(salpn)Cl2] (H2salpn = 1,3-bis(salicylideneamino)propane), which upon encapsulation in MSSP doubles its SOD activity. [ABSTRACT FROM AUTHOR]

Introduction: The nitro blue tetrazolium (NBT) reduction test (NBTT) has been used for measuring the metabolic activity of phagocytes of mammals. Activated neutrophils transform NBT into formazan in the cytoplasm. The NBTT can detect the activation of neutrophils in peripheral blood and is used to assess neutrophil function in dogs. However, the NBTT is not used frequently in the clinical setting, as samples should be processed after blood collection. Objective: The aim of this study was to evaluate the effect of storage on NBTT in dog blood samples. Materials and Methods: Residual EDTA blood samples from 22 dogs were included of different ages, breeds, and sex. The buffy coat layer was separated from the blood and incubated with 0.1% NBT. The NBTT was performed at 0, 24, 48, and 72 h after the collection of blood. Blood samples were stored at 4°C until the tests were performed. Blood smears were evaluated by light microscopy, and the NBT reduction rate was reported, which represents the percentage of activated neutrophils. The NBT reduction rate was calculated after counting 300 neutrophils in each slide. Results: The means of NBTT in dog blood samples at 0, 24, 48, and 72 h were 8.3%, 8.5%, 8.7%, and 7.8%, respectively. No significant differences were observed between time points. Conclusions: This study showed that the NBTT can be performed up to 72 h after the collection of canine blood if correctly refrigerated at 4°C. This finding supports the performance of the NBTT in the clinical setting. [ABSTRACT FROM AUTHOR]

A new eight series of 3-(2-oxo-2H-chromen-3-yl)-5-(substituted phenyl)-1H-pyrazole-1-carbaldehyde derivatives (9–16) were designed and created from coumarin-chalcone derivatives (1–8). The structures of the derivatives were established by using melting point, mass spectrum, IR, ¹HNMR, and 13C NMR spectroscopic methods. In vitro antiproliferative activities were evaluated against MCF-7 breast cancer cell line using Microculture Tetrazolium (MTT) assay. The results showed that the compounds 9, 12- 14 has a moderate activity against MCF-7 breast cancer cell line with IC50 61.44, 70.11, 22.6 and 25.99 µg/mL respectively, while the compounds 10,11, 15 and 16 were found to be inactive against studied cell line within IC50 > 100 µg/mL. The possible binding interaction between studied compounds (9–16) and human ER-α (PDB ID: 1ERR) were studied by molecular docking. The results revealed that only the compounds 11 and 16 form π -H interaction with ER-α (PDB ID: 1ERR) within the highest negative values of binding affinity -7.04260 and -7.17308 kcal.mol-1 respectively than the other compounds, while Raloxifene used here as a positive control form a strong ionic bonding with Asp 351 within the binding affinity -9.61928 kcal/mol which is more negative value than the studied compounds. [ABSTRACT FROM AUTHOR]

Two new vanadium (V) complexes involving 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR) and tetrazolium cation were studied. The following commercially available tetrazolium salts were used as the cation source: tetrazolium red (2,3,5-triphenyltetrazol-2-ium;chloride, TTC) and neotetrazolium chloride (2-[4-[4-(3,5-diphenyltetrazol-2-ium-2-yl)phenyl]phenyl]-3,5-diphenyltetrazol-2-ium;dichloride, NTC). The cations (abbreviated as TT+ and NTC+) impart high hydrophobicity to the ternary complexes, allowing vanadium to be easily extracted and preconcentrated in one step. The complexes have different stoichiometry. The V(V)–HTAR–TTC complex dimerizes in the organic phase (chloroform) and can be represented by the formula [(TT+)[VO2(HTAR)]]2. The other complex is monomeric (NTC+)[VO2(HTAR)]. The cation has a +1 charge because one of the two chloride ions remains undissociated: NTC+ = (NT2+Cl−)+. The ground-state equilibrium geometries of the constituent cations and final complexes were optimized at the B3LYP and HF levels of theory. The dimer [(TT+)[VO2(HTAR)]]2 is more suitable for practical applications due to its better extraction characteristics and wider pH interval of formation and extraction. It was used for cheap and reliable extraction–spectrophotometric determination of V(V) traces in real samples. The absorption maximum, molar absorptivity coefficient, limit of detection, and linear working range were 549 nm, 5.2 × 104 L mol−1 cm−1, 4.6 ng mL−1, and 0.015–2.0 μg mL−1, respectively. [ABSTRACT FROM AUTHOR]

By using tetrazole as the parent structural unit, five new groups of bicyclic tetrazolium-containing compounds (A--E) were designed by introducing a variety of high-energy and bridging groups. The electronic properties and detonation performances of the 35 designed compounds were calculated and analyzed using the density functional theory method at B3LYP/6-311G (d, p) level, and their detonation parameters were compared with those of HMX and other explosives. The results show that the densities of the five kinds of designed compounds are 1.555 9-2. 051 0g/cm³, the heat of formation are 490. 79-1 607. 39kJ/mol, the detonation velocities are 7 590-10 110m/s, and the detonation pressures are 23.34-48.44GPa. When the substituent groups are nitro, nitroamino and trinitro-methyl, the bridging groups are --N(NO2)--CH2--N(NO2)--, --N=N(O)-- and --N=N--, the densities of these compounds are 1. 90-2. 051 0g/cm³, the detonation velocities are 9 000-10 110m/s, the heat of formation(HOFs) are 916--1607kJ/mol, and the energy gap values are 1.45-5.62eV, indicating that they are potential energetic compound candidates with high energy density and excellent performance. [ABSTRACT FROM AUTHOR]

Simple Summary: This study aimed to understand the role of neutrophils in canine leishmaniosis (CanL) by assessing neutrophil activation and its relationship with different states of Leishmania infantum infection and antibody and IFN-γ production. The results showed that sick dogs in stage I-mild disease had significantly higher neutrophil activation compared to healthy seronegative and seropositive dogs and sick dogs in advanced stages (II, III–IV). Healthy seropositive dogs exhibited higher neutrophil activation compared to all other groups except sick dogs in stage I. Dogs in advanced disease stages (II, III–IV) did not show significant differences in neutrophil activation compared to healthy seronegative dogs. Furthermore, dogs in stage I had significantly higher IFN-γ concentrations compared to healthy seronegative and sick dogs in advanced disease stages. Dogs in stage II showed higher IFN-γ concentrations compared to healthy seronegative dogs, while no significant differences were observed in dogs in stage III–IV. Healthy seropositive dogs had elevated IFN-γ concentrations compared to healthy seronegative dogs and dogs in stage III–IV. These findings indicate that neutrophil activation is predominant in dogs with mild disease and healthy seropositive dogs with an association with potent IFN-γ production. This study aimed to investigate the role of neutrophils in canine leishmaniosis by assessing neutrophil activation and its relationship with different states of L. infantum infection and antibody and IFN-γ production. Dogs were categorized into five groups: healthy-seronegative (n = 25), healthy-seropositive (n = 21), LeishVet-stage I (n = 25), Leishvet-stage II (n = 41), and LeishVet-stage III–IV (n = 16). Results of the nitroblue tetrazolium reduction test (NBT) showed significantly higher neutrophil activation in stage I (median:17.17, range: [7.33–31.50]%) compared to in healthy-seronegative (4.10 [1.20–18.00]%), healthy-seropositive (7.65 [3.98–21.74]%), stage II (6.50 [1.50–28.70]%), and stage III–IV (7.50 [3.00–16.75]%) groups (p < 0.0001). Healthy-seropositive dogs also displayed higher values than all groups except stage I. Stages II and III–IV did not show significant differences compared to healthy-seronegative. Regarding IFN-γ, stage I dogs had higher concentrations (median:127.90, range: [0–3998.00] pg/mL) than healthy-seronegative (0 [0–109.50] pg/mL) (p = 0.0002), stage II (9.00 [0–5086.00] pg/mL) (p = 0.045), and stage III–IV (3.50 [80.00–548.80] pg/mL) (p = 0.02) dogs. Stage II dogs showed increased IFN-γ compared to healthy-seronegative dogs (p = 0.015), while stage III–IV dogs had no significant differences compared to healthy-seronegative dogs (p = 0.12). Healthy-seropositive dogs had elevated IFN-γ concentrations compared to healthy-seronegative dogs (p = 0.001) and dogs in stage III–IV (p = 0.03). In conclusion, neutrophil activation was higher in dogs with mild disease and healthy-seropositive dogs, and a relationship between neutrophil activation and the production of IFN-γ was found. [ABSTRACT FROM AUTHOR]

Background: Conservation and breeding programs for forest species require efficient pollen quality monitoring strategies to maximize collection, storage and pollination efforts. Question: Can the ImageJ image analysis software be implemented to efficiently monitor pollen viability and germinability for quality testing? Studied species: Pseudotsuga menziesii (Mirb.) Franco Methods: Tetrazolium staining and germination on 10 % Brewback media was used to test Douglas-fir pollen quality. Two macros for automated counting were developed with ImageJ free software using digitized microscopic images, and were tested to evaluate provenances, germination in different media, dehydration/rehydration and freeze-storage treatments, and finally to compare pollen quality between mature trees and GA-induced strobili from juvenile trees. Results: Automated monitoring of pollen quality was feasible because the software suitably distinguishes viable from non-viable pollen grains due to differential tetrazolium staining that translates into pixel density, whereas germinability was assayed based on pollen size and circularity. This tool was used to guide the selection of appropriate pollen handling conditions and compare pollen production in adult and GA-induced juvenile trees. Pollen flash-freezing and storage at -80 °C showed recovery between 74 and 98 % of its initial germinability after rehydration; however, viability detected by tetrazolium is reduced, suggesting that handling and storage affect the reliability of the test. Conclusions: The flexibility of the Fiji software allowed the development of an efficient and accurate macro for monitoring P. menziesii pollen quality, reducing invested time and effort involved, which supports future research on its conservation physiology and its successful application for germplasm production.

The species Ralstonia solanacearum (Smith) Yabuuchi, race 2, which causes bacterial hereque or moko in musaceae, constitutes a taxonomically complex unit that exhibits a wide genetic, physiological, serological and host range diversity. For this reason, two strains (R4 and R5) selected for their pathogenicity were identified and characterized. For this, 27 samples from 10 symptomatic plants were processed, from which colonies of irregular shape, flat elevation, mucoid appearance, thick edges, cream color and reddish central pigmentation of different intensities were obtained, using selective culture media such as nutrient agar and tetrazolium. Microscopic observations determined the presence of pure colonies, characterized as Gram-negative with straight and curved rods. Pathogenicity tests performed on healthy plants inoculated with the two strains by infiltration resulted in the characteristic symptomatology of the disease. For molecular identification, the universal primers U1 and U2 were used, which amplified a 996 bp band that, when sequenced and compared with the GeneBank® database, revealed 80.58% identity and 92% coverage in isolate R4, and 81.74% identity and 82% coverage for isolate R5. In addition, the specific primers OLI1 and Y2 were used, which amplified a band of 288 bp, allowing the identification of the samples studied as R. solanacearum. These isolates can be used in different breeding programs to search for tolerance to this pathogen and to generate strategies for the integrated management of the disease. [ABSTRACT FROM AUTHOR]

Tetrazolium test (TZT) can quickly evaluate in detail the viability and vigor of seeds. This study aimed to determine the optimal conditions for conducting the TZT on seeds of Handroanthus spongiosus. For this purpose, seeds from three lots were pre-soaked in water for 16 h, followed by extraction of the tegument and immersion in tetrazolium salt solutions at different concentrations (0.01–0.1%), for increasing periods (1–4 h) and at 30 °C in the dark. The experimental design was completely randomized with a 4 × 4 factorial scheme with 25 seeds per repetition. We applied generalized linear models and the Tukey test for pairwise comparisons of the means at 5% probability. The viability/vigor results were compared with data obtained from the germination test at 25 °C using a subsample of seeds from the same lots. The time (1 h to 4 h) of immersion of the seeds in tetrazolium salt solutions did not cause a clear coloration difference. The seeds subjected to all treatment concentrations for 3 h presented average viability greater than 60%, with no difference in germination percentage. The TZT at 0.01% tetrazolium salt solution for 3 h was most efficient in assessing the viability of the Handroanthus spongiosus seeds. [ABSTRACT FROM AUTHOR]

As a full nitrogen energetic anion, pentazolate (cyclo-N5?) holds great promise in the fields of propellants and explosives. Nowadays, nonmetallic pentazolate salts have received extensive attention as excellent nitrogen-rich energetic materials for their high enthalpies of formation, good oxygen balance, and eco-friendly decomposition products. In this study, a 1,4,5-triaminotetrazolium-based pentazolate salt (TATeþN5?, 8) with a nitrogen content of up to 90.30% was designed and synthesized. Its crystal structure indicates that a large number of hydrogen bonds form a hydrogen-bonded network, and the crystal has a mixed stacking pattern. TATeþN5?, which has a relatively high density (1.64 g·cm-3), high heat of formation (861.9 kJ·mol-1), and excellent detonation performances (detonation velocity: 9487 m·s-1, detonation pressure: 32.5 GPa), provides new insights into the stability of ultrahigh-nitrogen compounds. [ABSTRACT FROM AUTHOR]

Tetrazolium reduction and resazurin assays are the mainstay of routine in vitro toxicity batteries. However, potentially erroneous characterization of cytotoxicity and cell proliferation can arise if verification of baseline interaction of test article with method employed is neglected. The current investigation aimed to demonstrate how interpretation of results from several standard cytotoxicity and proliferation assays vary in dependence on contributions from the pentose phosphate pathway (PPP). Non-tumorigenic Beas-2B cells were treated with graded concentrations of benzo[a]pyrene (B[a]P) for 24 and 48 h prior to cytotoxicity and proliferation assessment with commonly used MTT, MTS, WST1, and Alamar Blue assays. B[a]P caused enhanced metabolism of each dye assessed despite reductions in mitochondrial membrane potential and was reversed by 6-aminonicotinamide (6AN)—a glucose-6-phosphate dehydrogenase inhibitor. These results demonstrate differential sensitivity of standard cytotoxicity assessments on the PPP, thus (1) decoupling "mitochondrial activity" as an interpretation of cellular formazan and Alamar Blue metabolism, and (2) demonstrating the implicit requirement for investigators to sufficiently verify interaction of these methods in routine cytotoxicity and proliferation characterization. The nuances of method-specific extramitochondrial metabolism must be scrutinized to properly qualify specific endpoints employed, particularly under the circumstances of metabolic reprogramming. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Ciencias Agricolas is the property of University of Narino, Faculty of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The MTT antibacterial assay is an important method in natural antibacterial component discovery. Researchers can use the MTT antibacterial assay to quickly and efficiently evaluate the antibacterial activity of natural compounds. The aim of this research was to find a method to reduce background colour and bacterial cell interference when using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay to study the antibacterial effect of phytochemicals. This study used NZ 'Hass' ripe avocado seed extract as an example to develop a silica gel column chromatography method that could combine with the MTT assay to remove the background colour and bacterial cells before the formazan measuring stage. This method is particularly suitable for MTT-based antibacterial inhibition studies when the tested phytochemical extracts have an interfering colour. [ABSTRACT FROM AUTHOR]

In this work, hydrazone, thiosemicarbazide, diamide, and dipeptide derivatives were prepared from the glycine and β-alanine hydrazide of 4-hydroxy-2-oxoquinoline. The desired derivative resulted from substitution, hydrazinolysis, condensation, and azide coupling reactions. The fabricated derivatives were screened for anticancer characteristics toward human’s colon carcinoma (HCT-116) cell line using the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide viability assay, while antioxidant property was examined using an in vitro H2O2 scavenging method. The β-alanine hydrazide derivative 3a showed a remarkable IC50 value of 18.8 μg/mL, whereas its corresponding thiosemicarbazide 5b exhibited moderate activeness with an IC50 value of 26.89 μg/mL. Conversely, the dipeptide derivative 7 with a Gly-βAla sequence showed better activity than the β-Ala-Gly derivative 8a. The IC50 values of 27.28 and 61.4 μg/mL, respectively, were achieved. According to an H2O2 scavenging activity test, the hydrazide of β-Ala derivative 2a displayed the best H2O2 scavenging property, with an IC50 value of 38.7 μg/mL. [ABSTRACT FROM AUTHOR]

Abstract: Asymbiotic germination techniques are successful in species of the Catasetum genus. The diverse composition of the culture media can be critical; however, viable seeds are required for asymbiotic germination. The reliable method for viability assessment is the tetrazolium test. A decisive step in the efficiency of the tetrazolium test is the seeds preconditioning with sucrose solution, which has the potential to improve germination. Therefore, this work aimed to evaluate the seed germination of three species of the genus Catasetum in culture media, preconditioned or not with sucrose solution. Seeds of the species Catasetum osculatum, Ctsm. galeritum and Ctsm. complanatum were assessed by tetrazolium test and germinated in two different media, pretreated or not with 10% sucrose solution. The statistical analysis showed that the use of sucrose pretreatment significantly increased the germination rates of the species. We conclude that the pretreatment with 10% sucrose for 24 hours, regardless of the species and the culture medium, significantly increases the germination of Ctsm. complanatum, Ctsm. galeritum and Ctsm. osculatum seeds.

Porphyrin compounds are widely distributed in various natural products and biological systems. In this study, effects of porphyrin-related compounds including zinc protoporphyrin (ZnPP), protoporphyrin IX (PPIX), cyanocobalamin (CBL), hemin, and zinc phthalocyanine (ZnPC) were analyzed on color response of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) tetrazolium-based assay, a commonly-used method for analyzing cell viability. Color responses of MTT formazan formed in cells treated with ZnPP, PPIX, or ZnPC were significantly reduced even at submicromolar concentrations without affecting cell viability, whereas hemin and CBL did not. ZnPP, PPIX, and ZnPC rapidly induced degradation of MTT formazan already-produced by cells when exposed to light, but not under a dark condition. Photosensitizing properties of the three compounds were also verified through extensive generation of reactive oxygen species under light. The porphyrins did not affect the stability of water-soluble formazans including XTT, WST-1, WST-8, and MTS formazans. Several factors including different light sources and antioxidants modulated the degradation process of MTT formazan by the porphyrins. The results suggest that certain porphyrin compounds could cause a severe artifact in the MTT assay through rapid degradation of formazan dye due to their photosensitizing property, which needs to be considered carefully in the related assays. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Seed Science is the property of Associacao Brasileira de Tecnologia de Sementes and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Moderate antiradical activity of 2H-chromen-2-one derivatives was established in a set of assays. The highest activity towards the superoxide radical anion (O2•–) generated in the model of enzymatic reduction of nitro blue tetrazolium was found for 4-[(1,2,3,4-tetra-hydro-1-oxonaphthalen-2-yl)(piperidin-1-yl)methyl]benzoic acid. In the non-enzymatic oxidation of epinephrine in an alkaline medium, like in other model systems, the highest activity was found for 4-(6-oxo-8,9-dihydro-6H,7H-benzo[h]-chromene[4,3-b]chromen-7-yl)benzoic acid. The absence of pronounced Fe2+-chelating activity and low reducing activity were revealed for 2H-chromen-2-one derivatives. In the model of long-lasting lipid peroxidation of tilapia liver, prolonged antioxidant effect was established for all of the test derivatives. [ABSTRACT FROM AUTHOR]

The title compound triphenyl tetrazolium (TPT) of phenobarbital, 5-Ethyl-5-phenylbarbituric acid triphenyl tetrazolium salt (4) was prepared by the reaction of 5-Ethyl-5-phenyl-2,4,6(1H, 3H, 5H)-pyrimidinetrione, monosodium salt (1) with triphenyl tetrazolium chloride (3) in deionized water at an ambient temperature through a cation exchange reaction. Colorless crystals of compound four suitable for an X-ray structural analysis were obtained by slow evaporation from acetonitrile. Compound four had crystallized in the monoclinic space group, P21/c, with a = 15.3678 (9) Å, b = 12.2710 (7) Å, c = 21.8514 (13) Å, β = 109.867 (2)°, V = 3875.5 (4) Å3, and Z = 4. A Through density functional theory (DFT) calculations, the probable molecular association structure in the phenobarbitone -triphenyl tetrazolium solution was studied. With the 6-311G-(d,p) basis set, the gas phase features of the phenobarbital-triphenyl tetrazolium clusters with a phenobarbitone dimer and water molecules, including an optimum structure and intermolecular hydrogen bonding, were investigated in detail. In addition, the positions and strengths of the intermolecular hydrogen bond interactions between the phenobarbitone and triphenyl tetrazolium molecules were analyzed using atoms in molecule (AIM) analysis, reduced density gradient (RDG) methods, the XRD method, and the non-covalent interaction (NCI) index method. In addition, the molecular electrostatic potential (MEP) surfaces were analyzed to determine the electrophilic and nucleophilic centers. [ABSTRACT FROM AUTHOR]

Kacang tanah (Arachis hypogea L.) merupakan komoditas kacang-kacangan utama di Indonesia karena memiliki sumber protein nabati dan nilai gizi yang tinggi. Salah satu faktor yang menghambat upaya peningkatan produksi kacang tanah yaitu minimnya benih yang bermutu tinggi yang dapat dipengaruhi oleh lama penyimpanan benih. Salah satu upaya yang dapat dilakukan untuk mengurangi rendahnya mutu suatu benih yaitu melakukan pengujian dini mutu benih. Penelitian ini bertujuan untuk mengetahui viabilitas benih kacang tanah varietas tuban dengan menggunakan uji tetrazolium dan daya berkecambah pada penyimpanan benih yang lama. Pengujian ini dilakukan dengan 2 metode yaitu uji tetrazolium dan uji daya berkecambah. Pengambilan sampel dilakukan dengan metode purposive sampling dengan 4 kali ulangan. Hasil penelitian menunjukkan bahwa terjadi penurunan viabilitas benih kacang tanah yang disimpan selama 1 tahun, dari 86% turun mencapai 34%, dengan kondisi kadar air meningkat dari 6.8% menjadi 7.4%. Selain itu, hasil uji daya berkecambah benih kacang tanah ditemukan sebanyak 34% normal, 45% kecambah abnormal dan 21% kecambah mati. Berdasarkan uji tetrazolium, ditemukan bahwa benih yang viabel sebesar 79% dan benih non viabel sebesar 21%. Hasil ini menunjukkan bahwa perlu adanya upaya peningkatan viabilitas dan daya berkecambah benih kacang tanah varietas tuban. Identifikasi awal kualitas benih merupakan hal yang penting bagi para pelaku usaha tani agar terhindar dari kegagalan panen.

Gel dosimetry is the most sensitive dosimeter since it is used in low-dose dosimetry. Using only thiazolyl blue tetrazolium bromide (TBTB), ethyl violet (EV), and bromothymol blue (BTB) dyes, three gels dosimetric structures made completely of gelatin were examined using a UV–Vis spectrophotometer. Radiation from γ-rays induces the radiochromic gel dosimeter TBTB-gelatin. The dose range for this gel at linearity up to 500 Gy. The EV-gel and BTB-gel dosimetry were both bleached by rays at 300 Gy and 250 Gy exposure linear ranges, respectively. Investigations were conducted on the dose-response function, radiation sensitivity, radiation chemical yield, and stability both before and after irradiation. [ABSTRACT FROM AUTHOR]

A facile one‐pot multicomponent route for the synthesis of acenaphtho[1,2‐b] pyrroles from acenaphthenequinone using amines and activated alkynes is reported. The method involves the formation of a zwitterionic intermediate through Huisgen dipolar cycloaddition reaction of amines and activated alkynes. The solvent free method was found to be superior than conventional methods in terms of reaction resulted in excellent yields in the presence of electron releasing and halogen containing substituents on the primary aromatic amine and on altering the alkyl substituents of the acetylenic ester. Antioxidant activity of the titled derivatives (4a‐j) was investigated by the Diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging method. Compounds 4b and 4j showed relative radical scavenging potential comparable to that of ascorbic acid (IC50 = 25.20 μg/mL). Cell growth inhibition testing was carried out using 3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5 diphenyl tetrazolium bromide (MTT) assay in two different human cancer cell lines colon (HT‐ 29) and breast (MCF‐7). Compound 4j is comparatively effective against HT‐29 cells (GI50 = 23.6 ± 0.11) in comparison with standard 5‐FU (GI50 = 25.5 ± 0.29) and also moderately effective against MCF‐7 cells (GI50 = 10.3 ± 0.12) in comparison with standard Doxorubicin (GI50 = 2.6 ± 0.06) among the other evaluated derivatives. The results revealed the promising lead compounds 4j for further optimization toward the discovery and development of new anti‐cancer agents. [ABSTRACT FROM AUTHOR]

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In this study, it was aimed to test the seed viability of Alkanna orientalis and endemic Alkanna sieheana species rich in Alkannin/Shikonin (A/S) and to determine the germination percentage and callus regeneration suitable for in vitro A/S production. The viability rates of seeds collected from nature were determined by the tetrazolium method. The germination rates of the seeds of both species were tested with three different applications (on filter paper, MS nutrient medium with agar, in peat). The seed coats of both species were removed, and their embryos were cultivated in Murashige and Skoog (MS) media containing plant growth regulators in various proportions. The viability rates of the seeds were found at 98.3% for A. orientalis and 96.0% for A. sieheana. Germination rates were determined only on filter paper as 8.3% for A. orientalis and 5.0% for A. sieheana, no germination was observed in other applications. The highest zygotic shoot and root formation rate were obtained from A. orientalis with 91.6% and 40.3%, respectively. But, the highest callus formation rate was observed on A. siehenea with 75.0%. As a result, it was determined that although the viability rates were high in both species, the germination rates were low, but in vitro reproducibility was possible.

• Chlorine pretreatments at 1% and 0.5% have a greater influence on the viability of C. gaskelliana and C. warscewiczii seeds. • Tetrazolium concentration and exposure time play an important role in the identification of viable seeds in C. gaskelliana and C. warscewiczii. • The culture media supplemented with coconut water and pineapple juice were the most suitable for the germination and formation of C. gaskelliana and C. warscewiczii seedlings. • The use of organic components in the culture media favors the germination of the seeds, stimulates the growth and development of C. gaskelliana and C. warscewiczii. Worldwide, orchid species are threatened mainly due to human action. For this reason, it is important search for inexpensive in vitro culture media that will help their rapid germination, propagation and conservation. Therefore, this research evaluated the viability, germination and in vitro development of Cattleya gaskelliana and Cattleya warscewiczii using different culture media. Capsules of the orchids were collected, seeds were submitted to different pretreatments (Chlorine 0.5%, Chlorine 1%, distilled water and Sucrose) and seed viability were tested with two concentrations of tetrazolium (0.25% and 0.5%) and two exposure times (24 h and 48 h). Afterwards, the seeds were grown on the following culture media: Murashige and Skoog (MS) basal medium, MS plus 0.5 mg L −1 of indoleacetic acid (MS+IAA), MS plus 0.5 mg L −1 of gibberellic acid (MS+GA3), MS supplemented with coconut water (MS+C), MS supplemented with pineapple juice (MS+ P) and the commercial medium Orchid Seed Sowing Medium (OSM). Viability for Cattleya gaskelliana was 90.6% in 0.5% tetrazolium, whereas for Cattleya warscewiczii was 90% in 0.25% concentration at 48 h exposure. The most efficient media regarding seedling development of C. gaskelliana and C. warscewiczii during 18 weeks of cultivation were MS+C and MS+ P with significant differences (P ≤ 0.05). The use of organic components in the culture media, favors the seeds germination, stimulates the growth and development of C. gaskelliana and C. warscewiczii, contributing in this way, in the decrease of costs generated by plant growth regulators. [ABSTRACT FROM AUTHOR]

Physical dormancy is typically found in Fabaceae species, including Gleditsia assamica. This type of dormancy can be alleviated, by mechanical scarification. Previous studies on the mechanical scarification effect on G. assamica seed focus only on its germination parameter without regard to its effect on seed water uptake. This study aims to understand the treatment effect on both seed water uptake and germination parameters. The tetrazolium dyeing test is conducted by immersing treated and untreated G. assamica seeds in 1% of tetrazolium solution for up to 72 hours. Cut test for the seeds was conducted at 24, 48, and 72 hours after immersion. Seed weight measurement trials were conducted by put treated and untreated G. assamica seeds in a petri dish with moist straw paper for up to 48 hours. Seeds were weighted at 24 and 48 hours to measure their water uptake rate. Lastly, a germination test for G. assamica seeds was conducted by germinating seeds for ten days in a completely randomized design of 25 seeds per replication for treated and untreated seeds. Germination is counted for each day and used to calculate germination parameters. This study result shows that mechanical scarification can enhance G. assamica seed water uptake. The treatment also significantly improved the seed's final germination percentage and germination speed index. This study result gives us a more precise understanding of the effect of mechanical scarification on alleviating G. assamica dormancy and germination. This study result will be advantageous to the species conservation and domestication efforts. [ABSTRACT FROM AUTHOR]

Objective: To determine the impact of the harvesting time of two coffee varieties on the physical quality and viability of seeds, using the tetrazolium testing. Design/Methodology/Approach: The research was carried out using a completely randomized design; the evaluation of the embryo viability was based on a five-color pattern staining design. The Garnica and Costa Rica 95 varieties and two harvesting times were used (December and January). An analysis of variance and a Tukey’s means comparison test (p≤0.05) were carried out, using the SAS 902 software. Results: The study varieties showed significative differences in all the variables related to the physical quality of the seeds, including volumetric weight and weight of 1,000 seeds. The best seed viability was obtained during the harvest carried out in January. Study Limitations/Implications: The results obtained are limited to the varieties in question, as well as the environmental conditions and period during which the said varieties were evaluated. Conclusions: The harvesting time of the two varieties of coffee has an influence on the physical characteristics of the seeds and on the viability, evaluation carried out using tetrazolium. [ABSTRACT FROM AUTHOR]

Poncirus trifoliata (L.) Raf., one of the main rootstocks in Argentina's citrus production, is propagated from seeds, which exhibit delayed germination due to physical dormancy. The biochemical tetrazolium test (TZ) allows a quick assessment of seed physiological quality. Even though the test has been applied to Poncirus, specific protocols for this species have not been developed yet. In the present work, a preliminary assay was carried out to test the TZ concentration and incubation time recommended by seed analyst associations (1% for 18 and 24h), the results of which were used to establish treatments suited to Poncirus. The TZ salt concentrations evaluated were 0.2 and 0.5%, with 3 and 5 h exposure to TZ, in a 2x2x2 factorial design. Seeds were classified as viable or non-viable according to the different staining obtained. It was determined that 5 h of incubation in 0.2% TZ salt concentration of unscarified seeds is the most suitable combination for assessing viability of Poncirus trifoliata seeds. way. [ABSTRACT FROM AUTHOR]

The nanoparticles have the potential ability of the passing cell membrane because of their size in nano meters. The SiO2 nanoparticles are one of the major and frequently used engineered oxide nanoparticles. In present investigation, the potential effect of SiO2 (10-20 nm) nanoparticles on maize seed viability were studied. We observed quick result of seed viability as well as increases in seed viability percentage in presence of Gibberellic acid (GA3) encapsulated silica nanoparticles. Three concentrations (0.5, 0.2 and 0.1%) of tetrazolium salts were used for staining of living tissue. The seeds preconditioned in 150 ppm GA3 encapsulated nanosilica and tested in 0.5% tetrazolium salt gave maximum viable seeds which were due to the increased availability of GA3 and showed quick staining over 0.2% and 0.1% concentration. Among the varieties, var. Navin imbibed in 150 ppm gibberellic acid encapsulated nanosilica showed a higher value of viable seed under 0.5% tetrazolium solution due to better availability of GA3. Gibberellic acid enhances metabolic activity of seed by secretion of a-amylase enzyme which is important for quick staining of embryonic tissue. [ABSTRACT FROM AUTHOR]

Anthropogenic toxic vapour and gases are a worldwide threat for human health and to the environment. Therefore, it is crucial to develop highly sensitive devices that guarantee their rapid detection. Here, we prepared redox-switchable colloids by the in-situ reduction of 2,3,5-triphenyl-2H-tetrazolium (TTC) into triphenyl formazan (TF) stabilised with Pluronic F127 in aqueous media. The colloids were readily embedded in polydimethylsiloxane (PDMS) to produce a selective colour-switchable membrane for nitrogen dioxide (NO2) detection. We found that the TTC reduction resulted in the production of red-coloured colloids with zeta potential between −1 to 3 mV and hydrodynamic diameters between 114 to 305 nm as hydrophobic dispersion in aqueous media stabilised by Pluronic at different molar concentrations. Moreover, the embedded colloids rendered highly homogenous red colour gas-permeable PDMS elastomeric membrane. Once exposed to NO2, the membrane began to bleach after 30 s due to the oxidation of the embedded TF and undergo a complete decolouration after 180 s. Such features allowed the membrane integration in a low-cost sensing device that showed a high sensitivity and low detection limit to NO2. [ABSTRACT FROM AUTHOR]

Introduction: Mesenteric thrombosis is a severe pathology with necrotization of intestinal tissues and death of the patient. The development of effective pharmacotherapy is an important task facing researchers. Materials and Methods: All studies were performed on 42 female white rats of the Wistar line, weighing 250±25 g. Segmental mesenteric thrombosis was reproduced by ligation of three segmental arteries in the area of the ileum. The volume of necrosis was determined by the triphenyl tetrazolium method. Results and Discussion: We have studied for the first time the effect of the arginase inhibitor L-norvaline on the volume of small intestine necrotized tissues in a model of acute segmental mesenteric thrombosis in rats. The study revealed a decrease in the volume of necrotic tissues from 32.39±0.47% to 23.84±0.39%, and the administration of glibenclamide did not cause complete cancellation of the L-norvaline action and led to a decrease in the volume of necrosis to 29.69±0.42%. Conclusion: Arginase inhibitor L-norvaline has protective effect in intestinal ischemia. [ABSTRACT FROM AUTHOR]

Natural herbal products are formulated with a combination of phytoconstituents from plants which play a pivotal role because of their diverse medicinal properties. Limited plants have been screened for their complete biological and pharmacological nature. In the present research work an attempt was made to infer the medicinal value of aqueous extract of Solanum torvum (S. torvum) leaves. Phytochemical analysis of the aqueous extracts of S. torvum leaf in the present study ascertain the presence of flavonoids, phenols, saponins, alkaloids, coumarins, sterols, proteins and reducing sugars. Further, the potentiality of aqueous extract of S. torvum leaves was assessed for its cytotoxic effect on Normal Vero cell line and anticancer activity on Human breast adenocarcinoma cell line by 3-(4, 5 dimethyl thiazole-2-yl) -2, 5-diphenyl tetrazolium bromide assay. A 24-hour incubation cell proliferation study reduced the cell viability of MCF-7 breast cancer cell lines. In vitro studies on cytotoxicity analysis on Vero cell line revealed that the aqueous leaf extract of S. torvum has no toxicity and further it was found to be effective in the prevention of cell proliferation by MCF-7 cell lines. [ABSTRACT FROM AUTHOR]

Kale (Brassica oleracea var. acephala) has great importance due to its easy propagation, acceptability and nutraceutical properties. The aim of the present work was to make methodological adjustments to conduct the tetrazolium test in kale seeds. Pre-tests were initially carried out to assess the priming time at 20 °C for 10 and 14 hours (times defined by the imbibition curve) and methods of removing the coat of kale seeds (total removal of the seed coat; cut in the distal region to the embryonic axis; longitudinal cut along the longest axis and whole seeds). Subsequently, the most efficient methodologies were evaluated using different concentrations of the tetrazolium salt solution (0.075%; 0.2%; 0.5% and 1.0%) and times (2, 4 and 6 h) of seed immersion in the solution, using four lots. The seeds were analyzed individually and classified as viable or non-viable. The tetrazolium test is efficient for evaluating the viability of kale seeds, providing results correlated with germination. Kale seeds should be primed between paper for 10 hours at 20 °C, and the seed coat should be removed for immersion in a 0.5% tetrazolium salt solution for 4 hours at 30 °C. [ABSTRACT FROM AUTHOR]

One of the most important problems of strawberry cultivation in temperate regions is winter cold injuries. Current study investigated impacts of foliar application of glycine betaine (GB) at 0, 0.5, 1, 2 and 4 mM concentrations on the cold hardiness of strawberry. The plants were divided into two groups: one group for evaluation of cold hardiness at temperatures of -6, -9, -12, -15 and -18 °C; and the other for study of some biochemical characteristics. Results showed that GB treatment increased soluble carbohydrate and proline concentrations in both leaf and crown tissues, total protein concentration in leaf, and relative water content in leaf as compared to those in control. Based on LT50 calculated from electrolyte leakage and tetrazolium staining test, the GB application increased cold hardiness in strawberry plant based on its concentration. The highest cold hardiness was found in the 2 mM GB concentration based on electrolyte leakage and tetrazolium staining tests at -13.3 and -15.3 °C. Meanwhile, the lowest values of cold hardiness were observed in the control treatments based on electrolyte leakage and tetrazolium staining tests at -10.2 and -11.0 °C. Significant correlations were found between soluble carbohydrate and proline concentrations in leaf and crown, and total protein concentration with LT50 calculated from electrolyte leakage and tetrazolium staining test. We conclude that application of 2 mM GB has the capacity to increase the freezing tolerance of strawberry and could be used as a prophylactic tool to reduce winter cold injury. [ABSTRACT FROM AUTHOR]

There is increasing interest in expanding grapevine production into colder regions. Here, to identify reliable methods for evaluating cold hardiness, we analyzed tissue discoloration, electrolyte leakage (EL), triphenyl tetrazolium chloride (TTC) reduction, and exotherms in the buds and canes of 'Campbell Early' grapevines. In both tissues, we monitored exotherms during cooling to − 40 °C at a rate of − 2 °C/h and analyzed the other indices during 2-h exposure to various freezing temperatures. Evaluating tissue discoloration is a subjective method to score freezing injury; it is more time-consuming and requires larger amounts of sample material than other methods but offers the advantage that it can be used to estimate LT50 (the temperature at which 50% injury occurs). EL analysis in buds and canes is another relatively rapid technique providing reproducible LT50 values. However, our EL analysis of buds was limited by the small amounts of sample material. For TTC reduction analysis, the results were not reproducible for both buds and canes: at the same freezing temperature, buds and canes showed significant differences in TTC reduction levels, leading to erroneous LT50 estimates. Finally, detection of low-temperature exotherms (LTEs), an indicator of intracellular ice formation (which causes fatal cell damage), through differential thermal analysis revealed LTEs in buds but seldom in canes, and those detected in buds exhibited much narrower peaks. Thus, exotherm and EL analyses are reliable methods for evaluating cold hardiness of grapevine buds and canes, respectively, and their combined application could be a useful strategy for assessing grapevine cultivars. [ABSTRACT FROM AUTHOR]

Microbial toxicity of test substances in tetrazolium assay is often quantified while referring to their IC50 values. However, the implication of such an estimate is very limited and can differ across studies depending on prevailing test conditions. In this work, a factorial design-based end-point microbial toxicity assay was performed, which suggests a significant interaction (P= 0.041) between inoculum and tetrazolium dose on formazan production. Subsequently, a dynamic model framework was utilized to capture the nonlinearities in biomass, substrate, formazan profiles and to project the toxicant inhibition parameter as a robust alternative to IC50 value. Microbial growth, glucose uptake and formazan production in the presence or absence of toxicant (Cu2+) from designed batch experiments were used for sequential estimation of model parameters, and their confidence intervals. A logistic growth model with multiplicative inhibition terms for formazan content and toxicant concentration fits the experimental data reasonably well (R2>0.96). Dynamic relative sensitivity analysis revealed that both microbial growth and formazan production profiles were sensitive to toxicant inhibition parameter. The modelling framework not only provides a better insight into the underlying toxic effect but also offers a stable toxicity index for the test substances that can be extended to design a versatile, robust in vitro assay system. [ABSTRACT FROM AUTHOR]

Over time, the effective resistance mechanisms to various first- and secondline drugs against the disease of tuberculosis make its treatment extremely difficult. This work presents a new approach to synthesizing a hybrid of antituberculosis medications: isoniazid (INH) and pyrazinamide (PZA). The synthesis was performed using ultrasoundassisted synthesis to obtain an overall yield of 70%, minimizing the reaction time from 7 to 1 h. The evaluation of the biological activity of the hybrid (compound 2) was tested using the tetrazolium microplate assay (TEMA), showing inhibition in the growth of Mycobacterium tuberculosis H37Rv at a concentration of 0.025 mM at pH 6.0 and 6.7. [ABSTRACT FROM AUTHOR]