- Determination of the activity of alkaline phosphatase based on aggregation-induced quenching of the fluorescence of copper nanoclusters. [Journal Article]
- MAMikrochim Acta 2018 Dec 07; 186(1):5
- A rapid method is described for synthesis of copper nanoclusters (CuNCs) by utilizing L-histidine as the stabilizer and ascorbic acid (AA) as the reductant. The CuNCs display blue-green fluorescence ...
A rapid method is described for synthesis of copper nanoclusters (CuNCs) by utilizing L-histidine as the stabilizer and ascorbic acid (AA) as the reductant. The CuNCs display blue-green fluorescence with excitation/emission peaks at 390/485 nm. A sensitive fluorometric assay was worked out for determination of alkaline phosphatase (ALP) activity. If the ALP substrate p-nitrophenylphosphate (PNPP) is enzymatically hydrolyzed, it forms p-nitrophenol (PNP) which reduces the fluorescence of CuNCs because its absorption band at 410 nm overlaps the excitation peak of CuNCs at 390 nm. In addition, the amino groups and imidazole groups on the surface of CuNCs possibly form a complex with the phenol groups of PNP. This induces aggregation-induced quenching of the fluorescence of CuNCs. The fluorescent probe has a linear analytical range that extends from 0.5 mU·mL-1 to 40 mU·mL-1 and a detection limit of 45 μU·mL-1. Graphical abstract Schematic illustration of a fluorometric assay for alkaline phosphatase (ALP) activity that uses L-histidine protected copper nanoclusters (CuNCs), aggregation-induced quenching, and the inner filter effect between PNP and CuNCs.
- Rapid and simple detection of ascorbic acid and alkaline phosphatase via controlled generation of silver nanoparticles and selective recognition. [Journal Article]
- AAnalyst 2018 Dec 10
- Ascorbic acid (AA) and alkaline phosphatase (ALP) serve as an important coenzyme and enzyme in multiple biological metabolism reactions, respectively, and abnormal levels of these substrates have bee...
Ascorbic acid (AA) and alkaline phosphatase (ALP) serve as an important coenzyme and enzyme in multiple biological metabolism reactions, respectively, and abnormal levels of these substrates have been associated with several diseases. Herein, a new and simple fluorescence strategy has been developed for AA and ALP sensing by exploiting CdTe quantum dots (QDs) as an effective signal indicator. This method is mainly based on the selective fluorescence-quenching reaction between Ag+ and CdTe QDs, as opposed to silver nanoparticles (Ag NPs); Ag+ can be reduced to Ag NPs by AA. Furthermore, by taking advantage of AA as a mediator, this strategy is further exploited for ALP assay given that ALP can cause the hydrolysis of l-ascorbic acid-2-phosphate (AAP), which yields AA. Under optimal conditions, controlled generation of Ag NPs and the selective recognition-based sensing system exhibit high sensitivity toward AA and ALP with limits of detection (LODs) of 3 μM and 0.25 U L-1 and linear ranges of detection from 0 to 800 μM and 1 to 1000 U L-1, respectively. Moreover, the sensor was successfully used for assaying AA in fruit juice and ALP in human serum. The results demonstrate that the proposed fluorescence strategy has significant advantages, such as its simplicity, cost-effectiveness, and rapid runtime, and the operational convenience of this label-free method further demonstrates its potential for constructing effective sensors with biochemical and clinical applications.
- Studies of human hemoglobin modified with peroxynitrite: A cytotoxic metabolite generated in numerous disorders. [Journal Article]
- IJInt J Health Sci (Qassim) 2018 Nov-Dec; 12(6):30-35
- CONCLUSIONS: Thus, the formation and effect of peroxynitrite on Hb are deleterious and antioxidant scavengers of the peroxynitrite show that the modification of the Hb can reverse the effect of peroxynitrite modification. The in vitro studies presented here show that peroxynitrite is toxic to human Hb and its inhibition by various antioxidants may be helpful in prevention of numerous disorders.
- Fluconazole induces ROS in Cryptococcus neoformans and contributes to DNA damage in vitro. [Journal Article]
- PlosPLoS One 2018; 13(12):e0208471
- Pathogenic basidiomycetous yeast, Cryptococcus neoformans, causes fatal meningitis in immunocompromised individuals. Fluconazole (FLC) is a fungistatic drug commonly administered to treat cryptococco...
Pathogenic basidiomycetous yeast, Cryptococcus neoformans, causes fatal meningitis in immunocompromised individuals. Fluconazole (FLC) is a fungistatic drug commonly administered to treat cryptococcosis. Unfortunately, FLC-resistant strains characterized by various degree of chromosomal instability were isolated from clinical patients. Importantly, the underlying mechanisms that lead to chromosomal instability in FLC-treated C. neoformans remain elusive. Previous studies in fungal and mammalian cells link chromosomal instability to the reactive oxygen species (ROS). This study provides the evidence that exposure of C. neoformans to FLC induces accumulation of intracellular ROS, which correlates with plasma membrane damage. FLC caused transcription changes of oxidative stress related genes encoding superoxide dismutase (SOD1), catalase (CAT3), and thioredoxin reductase (TRR1). Strikingly, FLC contributed to an increase of the DNA damage in vitro, when complexed with iron or copper in the presence of hydrogen peroxide. Strains with isogenic deletion of copper response protein metallothionein were more susceptible to FLC. Addition of ascorbic acid (AA), an anti-oxidant at 10 mM, reduced the inhibitory effects of FLC. Consistent with potential effects of FLC on DNA integrity and chromosomal segregation, FLC treatment led to elevated transcription of RAD54 and repression of cohesin-encoding gene SCC1. We propose that FLC forms complexes with metals and contributes to elevated ROS, which may lead to chromosomal instability in C. neoformans.
- Allantoin attenuates cadmium-induced toxicity in cucumber plants. [Journal Article]
- EEEcotoxicol Environ Saf 2018 Dec 04; 170:120-126
- Concentration-dependent responses of cucumber plants to cadmium (Cd, 5-15 µM) and/or allantoin (Alla, 10-1000 µM) have been investigated to detect a possible protective role of Alla under Cd excess. ...
Concentration-dependent responses of cucumber plants to cadmium (Cd, 5-15 µM) and/or allantoin (Alla, 10-1000 µM) have been investigated to detect a possible protective role of Alla under Cd excess. After 14 days of exposure, Alla often considerably reversed Cd-induced inhibition of growth and reduction of the content of photosynthetic pigments. Higher Alla doses depleted the Cd amount in shoots, which could be related to citric acid (increase in the shoots but depletion in the roots in Cd+Alla treatments) rather than to phytochelatins (Alla had a negative impact on the phytochelatin accumulation). An increase in the Alla concentration suppressed Cd-induced spatial H2O2 appearance, which does not seem to be related to antioxidative enzymes (low impact of Alla on catalase, ascorbate peroxidase, and guaiacol peroxidase). On the contrary, shoot glutathione and mainly ascorbic acid accumulation strongly increased in Cd+Alla treatments, indicating their prominent role in Alla-induced amelioration of Cd-stimulated oxidative stress and growth retardation. Similarly, phenolic metabolites (total soluble phenols and flavonols) were slightly influenced by Alla and their antioxidative action was not expected. We conclude that Alla-mediated attenuation of Cd-induced toxicity relies on enhanced accumulation of glutathione and ascorbate in the shoot tissue mainly, rather than on elevated antioxidative enzyme activities.
- Type I collagen deposition via osteoinduction ameliorates YAP/TAZ activity in 3D floating culture clumps of mesenchymal stem cell/extracellular matrix complexes. [Journal Article]
- SCStem Cell Res Ther 2018 Dec 07; 9(1):342
- CONCLUSIONS: These findings suggest that OIM-C-MSCs, which form a unique microenvironment that maintains high YAP/TAZ activity, can serve as better candidates for bone regenerative cell therapy than C-MSCs.
- [Is there a risk of adverse health effects from the consumption of fortified foods in Mexico?] [Journal Article]
- NHNutr Hosp 2018 Dec 03; 35(6):1356-1365
- CONCLUSIONS: we demonstrated that the nutriment concentrations in the FFP do not reach the UL values and are not a risk for the Mexican population; however, they improve the nutritional contribution of the FFP.
- First ethnobotanical inventory and phytochemical analysis of plant species used by indigenous people living in the Maromizaha forest, Madagascar. [Journal Article]
- JEJ Ethnopharmacol 2018 Dec 03
- CONCLUSIONS: These results confirmed the importance of investigating the traditional use of plant species, suggesting the crucial role of ethnobotanical studies for rural development, biodiversity conservation, and the sustainable use of plant resources in the studied area.
- Oxidation of cystatin imparted by riboflavin generated free radicals: Spectral analysis. [Journal Article]
- IJInt J Biol Macromol 2018 Dec 03
- Thiol Protease inhibitors (cystatins) are endogenous natural inhibitors of cysteine proteases. They are present in all mammalians cells and body fluids. Cystatin are allocated into three major famili...
Thiol Protease inhibitors (cystatins) are endogenous natural inhibitors of cysteine proteases. They are present in all mammalians cells and body fluids. Cystatin are allocated into three major families. Family -I stefins, family -II cystatins and family -III kininogens, according to their amino acid sequence, molecular weight, carbohydrate content and disulphide bonds. It has been investigated that thiol proteases (cathepsin) and their endogenous inhibitor, cystatins have been closely associated with diseases like Alzheimer's, Prions, neurodegenerative diseases, cancer and diabetes. Photodynamic effect of various sensitizers' have long been applied to delineate structural and functional properties of biologically active proteins. Flavins are well known to photo oxidize amino acids which effects conformation of proteins. Riboflavin (Vit B2) with a recommended daily requirement of approximately 2-3 mg is a yellow pigment, It is widely distributed in human tissues and blood, in both free and conjugated forms. In the present Study it has been shown that cystatin purified from buffalo brain (BC) is susceptible to reactive oxygen species generated by photo activation of riboflavin. It was observed that Photo activated riboflavin leads to inactivation of BC. Major Loss of tryptophan intensity was observed in the presence of purified thiol protease inhibitor upon incubation with 50 μM of riboflavin. In order to inspect the type of reactive oxygen species involved in inactivation of the inhibitor, different scavenger's were used namely glucose, potassium Iodide, sodium azide, manitol, thiourea, sodium benzoate, curcumin, quercetin, ascorbic acid and uric acid. It was found that Glucose, Potassium Iodide and sodium azide, have preventive effect on photo inactivation of the purified cystatin whilst other scavengers illustrated diminutive defensive effect.
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- Patulin removal from synbiotic apple juice using Lactobacillus plantarum ATCC 8014. [Journal Article]
- JAJ Appl Microbiol 2018 Dec 05
- CONCLUSIONS: Lactobacillus plantarum ATCC 8014 is capable of patulin removal from artificially contaminated synbiotic apple juice.Synbiotic apple juice artificially contaminated with patulin will be safe for consumers after the first day of probiotic inoculation and surface layer proteins of probiotic cells are responsible for patulin removal. This article is protected by copyright. All rights reserved.