Urinary Mercapturic Acids as Markers for the Determination of Isothiocyanate Release from Glucosinolates in Rats Fed a Cauliflower Diet

Glucosinolates, found in plants of the genus Brassica, release physiologically active metabolites, such as isothiocyanates and nitriles, in the digestive tract under the action of plant or bacterial myrosinase. Isothiocyanates are excreted in the urine as their mercapturic acid derivatives. To study the influence of diet on isothiocyanate release, two groups of eight rats were offered either a cauliflower-based diet or a standard laboratory rat diet. After 10 days' adaptation to the diets release of allyl isothiocyanate (AITC) from a single oral dose of sinigrin, a glucosinolate commonly occurring in brassicas, was quantified. Each rat was dosed with 50 μmol of either sinigrin or AITC by stomach tube and urine was collected at 0, 2, 6, 24 and 48 h after administration. Three days later, rats which had previously received sinigrin were administered with AITC and vice versa. The concentrations of urinary mercapturic acids of isothiocyanates were determined by HPLC. Recoveries of the mercapturic acid derivative of AITC in each animal were used to estimate AITC production in sinigrin-dosed rats. Estimates of AITC release from sinigrin showed that a greater proportion of administered sinigrin was hydrolysed to AITC in cauliflower-fed rats than in rats fed a control diet (0·412 vs 0·134; P〈0·001). The approach should allow more rigorous investigation of the influence of dietary factors on glucosinolate hydrolysis in vivo. © 1997 SCI.     

The Study of a 231 French Patient Cohort Significantly Extends the Mutational Spectrum of the Two Major Usher Genes MYO7A and USH2A

Usher syndrome is an autosomal recessive disorder characterized by congenital hearing loss combined with retinitis pigmentosa, and in some cases, vestibular areflexia. Three clinical subtypes are distinguished, and MYO7A and USH2A represent the two major causal genes involved in Usher type I, the most severe form, and type II, the most frequent form, respectively. Massively parallel sequencing was performed on a cohort of patients in the context of a molecular diagnosis to confirm clinical suspicion of Usher syndrome. We report here 231 pathogenic MYO7A and USH2A genotypes identified in 73 Usher type I and 158 Usher type II patients. Furthermore, we present the ACMG classification of the variants, which comprise all types. Among them, 68 have not been previously reported in the literature, including 12 missense and 16 splice variants. We also report a new deep intronic variant in USH2A. Despite the important number of molecular studies published on these two genes, we show that during the course of routine genetic diagnosis, undescribed variants continue to be identified at a high rate. This is particularly pertinent in the current era, where therapeutic strategies based on DNA or RNA technologies are being developed.     

Change in anthocyanin concentrations in red apricot fruits during ripening

Here we report on accumulation patterns of anthocyanins and of β-carotene during fruit maturation, between 82 and 125 days after flowering, of two apricot (Prunus armeniaca L.) cultivars, A3576 and A3751. Both cultivars displayed an intense red colour of the skin but differed in their genetic background. The pigments were extracted from skin and flesh, separately, and analysed using HPLC-DAD-MS. Out of three anthocyanins detected here, the major compound, cyanidin-3-O-rutinoside was present at 75%. The two minor compounds were cyanidin-3-O-glucoside and peonidin-3-O-rutinoside. This is the first time that peonidin-3-O-rutinoside has been detected in apricot fruit. During maturation, A3751 accumulated anthocyanins in both skin and flesh, whereas anthocyanins were present only in the skin of A3576. The skin anthocyanin content was higher in A3751 (296 mg kg⁻¹) than in A3576 (41 mg kg⁻¹). Maximum anthocyanin levels were attained after 108 and 118 days of flowering in A3751 and A3576, respectively, in conjunction with loss of firmness and red colour acquisition on the un-blushed side of the fruit. At the end of ripening, the β-carotene flesh concentration reached 5 mg kg⁻¹ in A3576 and 15 mg kg⁻¹ in A3751. A significant effect of environment was observed on the anthocyanin content in the two cultivars.     

Oxidation of lipid and protein in horse mackerel (Trachurus trachurus) mince and washed minces during processing and storage

Protein and lipid oxidation was followed during processing and storage of mince and washed minces prepared from horse mackerel (Trachurus trachurus). Briefly horse mackerel mince (M0) was washed with three volumes of water, mimicking the surimi production and different washed products were obtained: M1, M2 and M3, with one, two and three washing steps, respectively. The different products were characterised (i.e. lipid content, protein, water, iron, fatty acid profile and tocopherol content) and analysed for protein and lipid oxidation in order to investigate the impact of the washing steps on oxidation. Subsequently the different products were stored for up to 96 h at 5 °C and samples were taken out regularly for analysis. Lipid oxidation was investigated by measuring primary oxidation products (lipid hydroperoxides) and secondary oxidation products (volatiles). Protein oxidation was followed by determination of protein solubility, protein thiol groups and protein carbonyl groups using colorimetric methods as well as western blotting for protein carbonyl groups. Lipid and protein oxidation markers indicated that both lipid and protein oxidation took place during processing and the ranking for oxidation was as follows M0 < M1 < M2 ? M3 with M0 being significantly less oxidised than M3. Results indicated that washing creates an imbalance in the initial prooxidant-antioxidant equilibrium in the muscle tissue and contributes to the observed differences in the oxidative status of the four products obtained. In contrast, during storage of different products, lipid oxidation development was faster in M0 and the ranking was as follows M0 > M1 > M2 ? M3. Lipid and protein oxidation developed simultaneously in different minces during storage, but it was not possible to determine at which level these two reactions were coupled.     

Highly potent and specific GSK-3beta inhibitors that block tau phosphorylation and decrease alpha-synuclein protein expression in a cellular model of Parkinson's disease

Research by Klein and co-workers suggests that the inhibition of GSK-3beta by small molecules may offer an important strategy in the treatment of a number of central nervous system (CNS) disorders including Alzheimer's disease, Parkinson's disease, and bipolar disorders. Based on results from kinase-screening assays that identified a staurosporine analogue as a modest inhibitor of GSK-3beta, a series of 3-indolyl-4-indazolylmaleimides was prepared for study in both enzymatic and cell-based assays. Most strikingly, whereas we identified ligands having poor to high potency for GSK-3beta inhibition, only ligands with a Ki value of less than 8 nM, namely maleimides 18 and 22, were found to inhibit Tau phosphorylation at a GSK-3beta-specific site (Ser 396/404). Accordingly, maleimides 18 and 22 may protect neuronal cells against cell death by decreasing the level of alpha-Syn protein expression. We conclude that the GSK-3beta inhibitors described herein offer promise in defending cells against MPP+-induced neurotoxicity and that such compounds will be valuable to explore in animal models of Parkinson's disease as well as in other Tau-related neurodegenerative disease states.     

Mass spectrometry investigations on electrolyte degradation products for the development of nanocomposite electrodes in lithium ion batteries

In the continuing challenge to find new routes to improve the performance of commercial lithium ion batteries cycling in alkyl carbonate-based electrolyte solutions, original designs, and new electrode materials are under active worldwide investigation. Our group has focused on the electrochemical behavior of a new generation of nanocomposite electrodes showing improved capacities (up to 3 times the capacity of conventional electrode materials). However, moving down to "nanometric-scale" active materials leads to a significant increase in electrolyte degradation, compared to that taking place within commercial batteries. Postmortem electrolyte studies on experimental coin cells were conducted to understand the degradation mechanisms. Structural analysis of the organic degradation products were investigated using a combination of complementary high-resolution mass spectrometry techniques: desorption under electron impact, electrospray ionization, and gas chromatography coupled to a mass spectrometer equipped with electron impact and chemical ionization ion sources. Numerous organic degradation products such as ethylene oxide oligomers (with methyl, hydroxyl, phosphate, and methyl carbonate endings) have been characterized. In light of our findings, possible chemical or electrochemical pathways are proposed to account for their formation. A thorough knowledge of these degradation mechanisms will enable us to propose new electrolyte formulations to optimize nanocomposite-based lithium ion battery performance.     

The fission yeast spindle orientation checkpoint: a model that generates tension?

In all eukaryotes, the alignment of the mitotic spindle with the axis of cell polarity is essential for accurate chromosome segregation as well as for the establishment of cell fate, and thus morphogenesis, during development. Studies in invertebrates, higher eukaryotes and yeast suggest that astral microtubules interact with the cell cortex to position the spindle. These microtubules are thought to impose pushing or pulling forces on the spindle poles to affect the rotation or movement of the spindle. In the fission yeast model, where cell division is symmetrical, spindle rotation is dependent on the interaction of astral microtubules with the cortical actin cytoskeleton. In these cells, a bub1-dependent mitotic checkpoint, the spindle orientation checkpoint (SOC), is activated when the spindles fail to align with the cell polarity axis. In this paper we review the mechanism that orientates the spindle during mitosis in fission yeast, and discuss the consequences of misorientation on metaphase progression.     

Co-tunneling enhancement of the electrical response of nanoparticle networks

A co-tunneling charge-transfer process dominates the electrical properties of a nanometer-sized "slice" in a nanoparticle network, which results in universal scaling of the conductance with temperature and bias voltage, as well as enhanced spintronics properties. By designing two large (10 μm) electrodes with short (60 nm) separation, access is obtained to transport dominated by charge transfer involving "nanoslices" made of three nanoparticles only. Magnetic iron oxide nanoparticle networks exhibit a magnetoresistance ratio that is not reachable by tunneling or hopping processes, thereby illustrating how such a size-matched planar device with dominant co-tunneling charge-transfer process is optimal for realizing multifunctional devices with enhanced change of conductance under external stimulus.     

Neuronal architectures with axo-dendritic polarity above silicon nanowires

An approach is developped to gain control over the polarity of neuronal networks at the cellular level by physically constraining cell development by the use of micropatterns. It is demonstrated that the position and path of individual axons, the cell extension that propagates the neuron output signal, can be chosen with a success rate higher than 85%. This allows the design of small living computational blocks above silicon nanowires.     

Fluctuating renewables in a long-term climate change mitigation strategy

Integrated Assessment models, widely applied in climate change mitigation research, show that renewable energy sources (RES) play an important role in the decarbonization of the electricity sector. However, the representation of relevant technologies in those models is highly stylized, thereby omitting important information about the variability of electricity demand and renewables supply. We present a power system model combining long time scales of climate change mitigation and power system investments with short-term fluctuations of RES. Investigating the influence of increasingly high temporal resolution on the optimal technology mix yields two major findings: the amount of flexible natural gas technologies for electricity generation rises while the share of wind energy only depends on climate policy constraints. Furthermore, overall power system costs increase as temporal resolution is refined in the model, while mitigation costs remain unaffected.