Search results for "T complex"
showing 10 items of 151 documents
Crystallography of encapsulated molecules.
2017
The crystallography of supramolecular host–guest complexes is reviewed and discussed as a part of small molecule crystallography. In these complexes, the host binds the guests through weak supramolecular interactions, such as hydrogen and halogen bonding, cation–π, anion–π, C–H–π, π–π, C–H–anion interactions and the hydrophobic effect. As the guest often shows severe disorder, large thermal motion and low occupancies, the reliable crystallographic determination of the guest can be very demanding. The analysis of host–guest interactions using tools such as Hirshfeld and cavity volume surface analysis will help to look closely at the most important host–guest interactions. The jewel in the cr…
The oxidation of ubiquinol by the isolated rieske iron-sulfur protein in solution
1990
The pre-steady-state redox reactions of the Rieske iron-sulfur protein isolated from beef heart mitochondria have been characterized. The rates of oxidation by c-type cytochromes is much faster than the rate of reduction by ubiquinols. This enables the monitoring of the oxidation of ubiquinols by the Rieske protein through the steady-state electron transfer to cytochrome c in solution. The pH and ionic strength dependence of this reaction indicate that the ubiquinol anion is the direct reductant of the oxidized cluster of the iron-sulfur protein. The second electron from ubiquinol is diverted to oxygen by the isolated Rieske protein, and forms oxygen radicals that contribute to the steady-s…
An Inhibitor of Cytochrome Oxidase Activity in the Sea Urchin Egg
1959
PREVIOUS work in this laboratory1,2 has demonstrated the presence of a highly active cytochrome oxidase in the isolated mitochondria of unfertilized sea urchin eggs. This activity is only 25 per cent lower than that of the mitochondria of the newly fertilized egg and up to the blastula stage2. No cytochrome oxidase activity has been found other than in the mitochondria1,3. On the other hand, it is known that the oxygen consumption of the unfertilized sea urchin egg is quite low; fertilization restores a normal respiratory level which increases continuously during the early development (for a discussion, see ref. 4). The suggestion was then made2 that in the unfertilized egg an extra-mitocho…
Teams and project performance: an ability, motivation, and opportunity approach
2020
This article analyzes the relationships between project performance and the team’s ability, motivation, and opportunity (AMO). We contribute to the project management literature by exploring which combinations of AMO factors are best for project performance at different levels of complexity. We test our hypotheses on a sample of 285 projects. Our study shows that in simple projects, ability is the key factor both as a main effect and as a constraining factor that acts as a bottleneck for project performance. In the case of complex projects, the multiplicative model is superior given the significant interaction effects of motivation.
Mitochondrial and redox dysfunction in post-menopause as risk factor of neurodegenerative disease: a pilot study testing the role of a validated Japa…
2020
During the menopause women may experience increased oxidative stress and decreased antioxidant capacity and, together with the decline of neurosteroids, this represents a risk factor for Alzheimer's disease. The aim of the present study was to test a functional food (FPP-ORI, Osato Research Institute, Gifu, Japan) on redox and mitochondrial efficiency in post-menopausal women. The study population consisting of 69 untreated post-menopausal women were given supplements as follows: Group A was given a multivitamin (MV) 1c 2 times a day, and group B was given FPP 4.5 g 2 times a day. Group C consisted of 23 fertile premenopausal women as the control group. The tests carried out on entry, and a…
Magnetic exchange interactions in the heteropoly complexes [M4(H2O)2(PW9O34)2]10− [M=Co(II) and Cu(II)]
1990
The magnetic properties of the heteropolyanions [M4(H2O)2(PW9O34)2]10− [M=Co(II) and Cu(II)] down to 4 K are reported. Their individual heteropoly molecules contain a rhomblike arrangement formed by four coplanar MO6 octahedra sharing edges. The magnetic properties support an intramolecular ferromagnetic exchange in the Co(II) tetramer, and antiferromagnetic exchange in the Cu(II) tetramer. These behaviors are discussed assuming anisotropic exchange in the Co(II) compound, and Heisenberg exchange in the Cu(II) compound. Carlos.Gomez@uv.es
Synthesis of N-diisopropyl phosphoryl benzyl-tetrahydroisoquinoline, a new class of mitochondrial complexes I and III inhibitors
2000
The synthesis of N-(O,O-diisopropylphosphoryl)-benzyltetrahydroisoquinoline (3) has been achieved in a 'one pot' procedure from imine (2) and diisopropyl-phosphorochloridate (1) generated in situ (POCl3 + iPrOH). Compound 3 is the first benzyltetrahydroisoquinoline derivative found to be a potent inhibitor of mitochondrial complexes I and III, and therefore it opens a new perspective with this series of compounds as they can be considered as new class of antitumor agents.
Retrotransposon activation by distressed mitochondria in neurons
2020
Retrotransposon activation occurs in a variety of neurological disorders including multiple sclerosis and Alzheimer's Disease. While the origins of disease-related retrotransposon activation have remained mostly unidentified, this phenomenon may well contribute to disease progression by inducing inflammation, disrupting transcription and, potentially, genomic insertion. Here, we report that the inhibition of mitochondrial respiratory chain complex I by pharmacological agents widely used to model Parkinson's disease leads to a significant increase in expression of the ORF1 protein of the long interspersed nucleotide element 1 (LINE1) retrotransposon in human dopaminergic LUHMES cells. These …
Downregulation of PMCA2 increases the vulnerability of midbrain neurons to mitochondrial complex I inhibition
2013
Parkinson's disease is an age-associated disorder characterized by selective degeneration of dopaminergic neurons. The molecular mechanisms underlying the selective vulnerability of this subset of neurons are, however, not fully understood. Employing SH-SY5Y neuroblastoma cells and primary mesencephalic neurons, we here demonstrate a significant increase in cytosolic calcium after inhibition of mitochondrial complex I by means of MPP(+), which is a well-established environmental toxin-based in vitro model of Parkinson's disease. This increase in calcium is correlated with a downregulation of the neuron-specific plasma membrane Ca(2+)-ATPase isoform 2 (PMCA2). Interestingly, two other import…
Life cycle of Renylaima capensis, a brachylaimid trematode of shrews and slugs in South Africa: two-host and three-host transmission modalities sugge…
2012
Abstract Background The life cycle of the brachylaimid trematode species Renylaima capensis, infecting the urinary system of the shrew Myosorex varius (Mammalia: Soricidae: Crocidosoricinae) in the Hottentots Holland Nature Reserve, South Africa, has been elucidated by a study of its larval stages, epizootiological data in local snails and mammals during a 34-year period, and its verification with mtDNA sequencing. Methods Parasites obtained from dissected animals were mounted in microscope slides for the parasitological study and measured according to standardized methods. The mitochondrial DNA cox 1 gene was sequenced by the dideoxy chain-termination method. Results The slugs Ariostralis …