Respiration deficient mutants of Schizosaccharomyces Pombe I.
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Electron Transport↗
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Results for “TETRAZOLIUM COMPOUNDS”
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Evaluation of anticancer activity of 4-vinyl-1-arylsulfonylimidazolidinones.
To continue exploration of structure activity relationship of novel 1-(indoline-5-sulfonyl)-4-phenylimidazolidinones (1) reported as anticancer agent with broad spectrum, three 1-(arylsulfonyl)-4-vinylimidazolidinones (2) were synthesized from methyl serinate (3) in 8 steps. Reaction of intermediate 2-phenoxycarbonylaminobut-3-enyl p-toluenesulfonate (10) with arylsulfonamide in the presence of potassium carbonate produced corresponding 2 and N-(4-vinyloxazolidin-2-yl)arylsulfonamide 11 in approximately equal ratio. This reaction is believed to undergo through urea intermediate 16 as shown in scheme 3. 1-Arylsufonyl-4-vinylimidazolidinones 2 show much reduced activity against human colon carcinoma (Colo205), human chronic myelogenous leukemia (K562), and human ovarian adenocarcinoma (SK-OV-3) and compatible activity against human lung carcinoma (A549) compared to 1. Therefore phenyl at 4-position should be the optimum planar motif for the activity of 1.
Antineoplastic Agents↗
Native agarose-polyacrylamide gel electrophoresis allowing the detection of aminopeptidase, dehydrogenase, and esterase activities at the nanogram level: enzymatic patterns in some Frankia strains.
Nanogram amounts of soluble aminopeptidases, dehydrogenases, and esterases were detected by nondenaturing ultralow gelling point agarose-polyacrylamide gel electrophoresis (ULGA-PAGE). Cytosolic fractions from Frankia sp. were electrophoresed at 4 degrees C in the presence of Co2+, Zn2+, or Mg2+ ions. Then, aminopeptidases and esterases were revealed by simultaneous capture staining by using fast garnet GBC diazonium salt as the chromogenic coupling compound. Dehydrogenases were revealed by using nitro blue tetrazolium salt as electron acceptor. A variety of aminopeptidases, dehydrogenases, and esterases could be identified by their migration in ULGA-PAGE and by their sensitivities to NaCl, CoSO4, ZnSO4, and MgCl2 when assayed "ingel." The presence of agarose was essential for the detection of the complex enzyme patterns. The patterns were remarkably similar for the five Frankia strains isolated from Allocasuarina and Casuarina host plants and differed from those of Frankia strains isolated from Comptonia and Hippophaë host plants. A nomenclature is proposed for aminopeptidases and other Frankia enzymes. The richness of the Frankia amino-peptidases and esterases zymograms makes them adequate marker enzymes for taxonomical, genetic, or biochemical studies. Dehydrogenases might also be useful, although a more restricted number of bands were found with L-lactic and L-malic acid as substrates.
Actinomyces↗
Application of a gastric cancer cell line (MKN-28) for anti-adenovirus screening using the MTT method.
We established a sensitive and accurate method for screening of anti-adenovirus agents using the 3-(4,5-dimetylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. MKN-28 cells, which are well-differentiated stomach adenocarcinoma cells, were used for adenovirus (ADV) infection and examined for the anti-ADV activities of several established anti-herpes virus agents. ADV-11 is the causative agent of respiratory and urinary infections. It frequently causes hemorrhagic cystitis in immunocompromised hosts. One laboratory strain and 4 clinical isolates of ADV-11 were examined, and found susceptible (in order of decreasing activity) to 2-amino-7-[(1,3-dihydroxy-2-propoxy)methyl]purine (S-2242), (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine[(S)-HPMPA ], and (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine[(S)-HPMPC++ +]. On the other hand, ganciclovir and iododeoxyuridine were only weakly effective and dextran sulfate was ineffective. Our findings indicate that the MTT assay using MKN-28 cells is applicable to anti-ADV screening. The anti-ADV activity of (S)-HPMPA and (S)-HPMPC was confirmed, and, furthermore, S-2242 emerged as a highly potent and selective inhibitor of ADV-11.
Adenine↗
Phosphorylation of tyrosine enhances its electron transfer capability: a model of redox modulation as oncogene expression?
The influence of tyrosine and o-phosphotyrosine on the transfer of electrons to nitrobluetetrazolium (NBT) was studied. Tyrosine phosphate was found to strongly promote the transfer of electrons from ferrous iron to NBT, while tyrosine was inhibitory. The enhancement of NBT reduction by tyrosine phosphate was blocked by superoxide dismutase (SOD). The results suggest a role for phosphorylated tyrosine residues to promote intracellular redox reactions. We suggest that the role of tyrosine protein kinases in cell proliferation and transformation may be to regulate electron transport in as yet undefined cellular systems. Consistent with a unique role for phosphotyrosine, the other commonly occurring phosphoamino acids, o-phosphoserine and o-phosphothreonine were not effective electron transfer agents.
Electron Transport↗
Sequential analysis of infarcted and normal myocardium in piglets using in vivo gadolinium-enhanced MR images.
Gadolinium-enhanced magnetic resonance (MR) imaging was performed before, and 1 and 3 wk after coronary occlusion in domestic piglets. After administration of the contrast agent gadopentetate dimeglumine, two different enhancement patterns within the infarcted region were observed. The first pattern, showing peripheral enhancement of the infarcted region with absence of contrast in the center, was seen at 1 wk after occlusion at 5 min after administration of the contrast agent. The second pattern showed signal enhancement of the center of the infarcted region and was observed at 1 wk after occlusion, 30 min following contrast administration, and at 3 wk after occlusion, both 5 and 30 min following contrast administration. Infarct size and left ventricular (LV) mass by MR imaging, measured 3 wk after infarction, corresponded well with pathologic assessment. LV mass, measured by static and dynamic MR imaging, increased during the period of investigation. It is concluded that gadolinium-enhanced MR imaging clearly identifies infarcted myocardium early and late after coronary occlusion in the piglet. Combined results of infarct size and LV mass can be obtained simultaneously during one imaging procedure.
Animals↗
Identification of caffeoylquinic acid derivatives from Brazilian propolis as constituents involved in induction of granulocytic differentiation of HL-60 cells.
We have previously reported that Brazilian propolis extracts inhibited growth of HL-60 human myeloid leukemia cells, which is partly attributed to the induction of apoptosis associated with granulocytic differentiation. In this study, we isolated three compounds which induce granulocytic differentiation evaluated by nitroblue tetrazolium (NBT)-reducing assays from the water extract of propolis and identified as 4,5-di-O-caffeoylquinic, 3,5-di-O-caffeoylquinic, and 3,4-di-O-caffeoylquinic acids by NMR analysis. Cell growth inhibitory activity of these caffeoylquinic acids was found in HL-60 cell, which was mainly attributed to the induction of apoptosis. Furthermore, the potency of caffeoylquinic acid derivatives to induce granulocytic differentiation was examined in HL-60 cells. Caffeic, quinic, and chlorogenic acids had no effects on the NBT-reducing activity, while 3,4,5-tri-O-caffeoylquinic acid induced more than 30% of NBT-positive cells. These results suggest that the number of the caffeoyl groups bound to quinic acid plays an important role in the potency of the caffeoylquinic acid derivatives to induce granulocytic differentiation. This is the first report demonstrating that the caffeoylquinic acid derivatives induce granulocytic differentiation of HL-60 cells.
Cell Differentiation↗
Optimization and validation of a colorimetric assay for Tetrahymena sp. survival.
A colorimetric assay based on the reduction of 3-(4,5-dimethyl-2-thiazol-2-yl)-2,5-diphenyl-2h-tetrazolium bromide (MTT), for the quantification of Tetrahymena sp. survival is described. An increase in the concentration of Tetrahymena sp. cells from 0 to 1 x 10(6) cells/ml produced a linear (R(2)=0.9965) increase in the optical density (OD, 570-630 nm), and dead cells (pre-exposed to 250 mg/l formalin for 4 h) did not produce a background reading. Cells exposed to sublethal concentrations to formalin (100 mg/l or less for 4 h) recovered their growth. Using the MTT assay, we determined that Tetrahymena sp. is sensitive to formalin, chloramine-T, hydrogen peroxide, copper sulfate and NaCl. The sensitivity increased with increasing chemical concentrations and exposure time. Tetrahymena sp. was resistant to bromex and malachite green. The use of this assay in drug screening for the development of treatments for tetrahymenosis and as a bioassay to evaluate the toxicity of environmental toxicants is discussed.
Animals↗
Microglia is activated by astrocytes in trimethyltin intoxication.
Microglia participates in most acute and chronic neuropathologies and its activation appears to involve interactions with neurons and other glial cells. Trimethyltin (TMT)-induced brain damage is a well-characterized model of neurodegeneration, in which microglial activation occurs before neuronal degeneration. The aim of this in vitro study was to investigate the role of astroglia in TMT-induced microgliosis by using nitric oxide (NO), inducible NO synthase (iNOS), and morphological changes as parameters for microglial activation. Our investigation discusses (a) whether microglial cells can be activated directly by TMT; (b) if astroglial cells are capable of triggering or modulating microglial activation; (c) how the morphology and survival of microglia and astrocytes are affected by TMT treatment; and (d) whether microglial-astroglial interactions depend on direct cell contact or on soluble factors. Our results show that microglia are more vulnerable to TMT than astrocytes are and cannot be activated directly by TMT with regard to the examined parameters. In bilayer coculture with viable astroglial cells, microglia produce NO in significant amounts at subcytotoxic concentrations of TMT (20 micromol/l). At these TMT concentrations, microglial cells in coculture convert into small round cells without cell processes, whereas flat, fibroblast-like astrocytes convert into thin process bearing stellate cells with a dense and compact cell body. We conclude that astrocytes trigger microglial activation after treatment with TMT, although the mechanisms of this interaction remain unknown.
Animals↗
A convenient assay of glycoserum by nitroblue tetrazolium with iodoacetamide.
BACKGROUND: To determine glycoserum, the nitroblue tetrazolium (NBT) assay is quick, economical, convenient and easily automated. This method, however, is vulnerable to interference by thiol group, which should not be ignored during the analysis. METHODS: Thiol group in glycoserum was blocked with iodoacetamide (IAM) before NBT was added. The reaction was carried out in a thermal bath and terminated on ice. The absorbance was measured at either 570 or 530 nm. RESULTS: IAM (3-10 mmol/l) did not give any detectable interference in the NBT assay. The absorbance at both 570 and 530 nm was linearly related to the concentration of either glycoserum or 1-deoxy-1-morpholino-D-fructose (DMF) that had been treated with IAM. The assay showed a good discrimination between diabetic and normal subjects (t-test, P < 0.001). Uric acid and lipemia under physiological conditions did not interfere with NBT reaction. The assay was affected by hyperlipemia and hematolysis. CONCLUSIONS: IAM-modified method prevented NBT assay from the interference by thiol group and uric acid.
Blood Glucose↗
N.B.T. test in malaria.
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Bacterial Infections↗
Effect of oxygen on a stimulated N.B.T. test.
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Adult↗
Use of novel assays to indicate that O-esters and S-esters are produced by the same enzyme in brewing yeast.
Ethanol- and methanethiol-dependent removal of acetyl-CoA by crude extracts of ale yeast has been monitored using a decrease in OD232. Activity has also been detected in these extracts after fractionation on polyacrylamide gels, in this case using a novel assay in which the coenzyme A produced in the reaction is linked via DCPIP reduction to color formation from nitroblue tetrazolium. Ethanol- and methanethiol-dependent activities migrate identically on such gels, and only one band of color formation was observed. Furthermore they displayed closely similar sensitivity to heating at 40 degrees C and 60 degrees C and pH optima, with activity maximal at pH 7.5. It is likely that a single enzyme is responsible for the formation of O-esters and S-esters in yeast. Initial kinetic studies indicate that methanethiol has higher affinity for the enzyme than has ethanol and a higher maximum velocity. However, the enzyme has a much lower Km for acetyl-CoA, suggesting that the alcohol or thiol substrate is the more likely substrate to be limiting.
Acetyl Coenzyme A↗
Anticarcinogenic effects of glycoalkaloids from potatoes against human cervical, liver, lymphoma, and stomach cancer cells.
Methods were devised for the isolation of large amounts of pure alpha-chaconine and alpha-solanine from Dejima potatoes and for the extraction and analysis of total glycoalkaloids from five fresh potato varieties (Dejima, Jowon, Sumi, Toya, and Vora Valley). These compounds were then evaluated in experiments using a tetrazolium microculture (MTT) assay to assess the anticarcinogenic effects of (a) the isolated pure glycoalkaloids separately, (b) artificial mixtures of the two glycoalkaloids, and (c) the total glycoalkaloids isolated from each of the five potato varieties. All samples tested reduced the numbers of the following human cell lines: cervical (HeLa), liver (HepG2), lymphoma (U937), stomach (AGS and KATO III) cancer cells and normal liver (Chang) cells. The results show that (a) the effects of the glycoalkaloids were concentration dependent in the range of 0.1-10 mug/mL (0.117-11.7 nmol/mL); (b) alpha-chaconine was more active than was alpha-solanine; (c) some mixtures exhibited synergistic effects, whereas other produced additive ones; (d) the different cancer cells varied in their susceptibilities to destruction; and (e) the destruction of normal liver cells was generally lower than that of cancer liver cells. The decreases in cell populations were also observed visually by reversed-phase microscopy. The results complement related observations on the anticarcinogenic potential of food ingredients.
Anticarcinogenic Agents↗
Activation of the androgen receptor N-terminal domain by interleukin-6 via MAPK and STAT3 signal transduction pathways.
The androgen receptor (AR) is a ligand-activated transcription factor that mediates the biological responses of androgens. However, non-androgenic pathways have also been shown to activate the AR. The mechanism of cross-talk between the interleukin-6 (IL-6) and AR signal transduction pathways was investigated in LNCaP human prostate cancer cells. IL-6 induced several androgen-response element-driven reporters that are dependent upon the AR, increased the phosphorylation of mitogen-activated protein kinase (MAPK), and activated the AR N-terminal domain (NTD). Inhibitors to MAPK and JAK decreased the IL-6-induced phosphorylation of MAPK and activation of the AR NTD. Immunoprecipitation and transactivation studies showed a direct interaction between amino acids 234-558 of the AR NTD and STAT3 following IL-6 treatment of LNCaP cells. These results demonstrate that activation of the human AR NTD by IL-6 was mediated through MAPK and STAT3 signal transduction pathways in LNCaP prostate cancer cells.
Amino Acids↗
Effect of thiols on fructosamine assay.
Fresh human serum, gGAPDH and beta-mercaptoethanol were used to examine the effect of thiols on fructosamine assay. The kinetics of the reaction with both fresh human serum and gGAPDH displayed biphasic behaviour (fast and slow). When the thiols were modified with IAA, the kinetics only demonstrated the slow phase. Since the absorbance increase in the interval from 9 to 10 min was used in the fructosamine assay of glycated human serum we studied the effect of thiols on that measurement. In the case of gGAPDH, the value was approximately one-half of the original after thiol modification, suggesting thiol interference. Nevertheless, gGAPDH may contain a fructosamine structure. beta-Mercaptoethanol itself gave a strong positive result in the fructosamine assay. Hence, thiol groups on glycated proteins should be modified before doing a fructosamine assay because of their substantial interference.
Blood↗
In vitro cytotoxicity of nanoparticles in mammalian germline stem cells.
Gametogenesis is a complex biological process that is particularly sensitive to environmental insults such as chemicals. Many chemicals have a negative impact on the germline, either by directly affecting the germ cells, or indirectly through their action on the somatic nursing cells. Ultimately, these effects can inhibit fertility, and they may have negative consequences for the development of the offspring. Recently, nanomaterials such as nanotubes, nanowires, fullerene derivatives (buckyballs), and quantum dots have received enormous national attention in the creation of new types of analytical tools for biotechnology and the life sciences. Despite the wide application of nanomaterials, there is a serious lack of information concerning their impact on human health and the environment. Thus, there are limited studies available on toxicity of nanoparticles for risk assessment of nanomaterials. The purpose of this study was to assess the suitability of a mouse spermatogonial stem cell line as a model to assess nanotoxicity in the male germline in vitro. The effects of different types of nanoparticles on these cells were evaluated by light microscopy, and by cell proliferation and standard cytotoxicity assays. Our results demonstrate a concentration-dependent toxicity for all types of particles tested, whereas the corresponding soluble salts had no significant effect. Silver nanoparticles were the most toxic while molybdenum trioxide (MoO(3)) nanoparticles were the least toxic. Our results suggest that this cell line provides a valuable model with which to assess the cytotoxicity of nanoparticles in the germ line in vitro.
Animals↗
Practical applications of neuronal tissue culture in in vitro toxicology.
1. Primary chick embryo forebrain neurones are relatively easy to culture and are quite resilient to treatment manipulation. These characteristics have allowed application in a surprisingly diverse number of areas. 2. These cultures have been used to investigate the anticholinesterase potencies of many organophosphate (OP) nerve agents and insecticides. 3. These cultures have been used to quantitate levels of OP in 'spiked' unknowns and in OP-contaminated soil samples. 4. These cells have also been used to test a variety of compounds using the MTT and neutral red cytotoxicity assays.
Animals↗