Metal complexes of N-hydroxy-imino-di-α-propionic acid and related ligands

N-hydroxy-imino-di-α-propionic acid, the ligand present in the natural oxovanadium(IV) complex ‘amavadin’ which occurs in the toadstool Amanita muscaria, has been synthesised, as well as two related ligands—N-hydroxy-iminodiacetic acid and imino-di-α-propionic acid—useful for comparison purposes. The formation of complexes of these ligands with VO²⁺, Ni²⁺ has been studied and their stability constants have been determined.The two N-hydroxy-substituted ligands, of low basicity, form ML₂ complexes with VO²⁺, unlike the more basic derivatives of iminodiacetic acid. Since substitution of ligands bonded to the apical site trans to the oxo ligand is very fast and the formation of ML₂ complexes of VO²⁺ exposes that apical site to the reaction media, this may be the reason why oxovanadium(IV) and the unusual derivative of iminodiacetic acid present in ‘amavadin’ were selected for the biological role that this complex plays in the toadstool.     

Cross-species amplification of Medicago truncatula microsatellites across three major pulse crops

Model plants are facilitating the genetic characterization and comparative mapping of a number of traditional crops. Medicago truncatula has been widely accepted as a model plant to this end as it provides the essential tools for multiple aspects of legume genetics and genomics. A large set of markers from highly conserved M. truncatula gene regions is being created and used to establish a worldwide framework for comparative genomic studies in legumes. We have investigated the potential for cross-species amplification of 209 expressed sequence tag (EST)-based and 33 bacterial artificial chromosome (BAC)-based microsatellites from M. truncatula in the three most important European legume pulses—pea, faba bean and chickpea—that might facilitate future comparative mapping. Our results revealed significant transferability of M. truncatula microsatellites to the three pulses (40% in faba bean, 36.3% in chickpea and 37.6% in pea). The percentage of M. truncatula EST-SSRs (simple sequence repeats) amplified in the three crops (39–43%) was twofold higher than that of the genomic SSRs (21–24%). Sequence analysis determined that the level of conservation in the microsatellite motif was very low, while the flanking regions were generally well conserved. The variations in the sequences were mainly due to changes in the number of repeat motifs in the microsatellite region combined with indel and base substitutions. None of the functional microsatellites showed direct polymorphism among the parental genotypes tested, consequently preventing their immediate use for mapping purposes.Electronic Supplementary Material Supplementary material is available for this article at     

Synthesis and characterisation of [[μ-(1,7,11,17-tetraaza-2,6,12,16-tetraoxacycloeicosane)][(μ-(aquo)]bis[(acac)(ethanol)nickel(II)]] [BPh4]2

The pale blue title compound, 4, was obtained from the reaction between 1,7,11,17-tetraaza-2,6,12,16-tetraoxacycloeicosane, Ni(acac)₂ and NaBPh₄ in aqueous acetone. X-ray structure determination at 120 K revealed that the dication of the ionic complex, 4, contains two independent octahedral Ni^II centres with trans-Ni₂N₂O₄ chromophores. The macrocyclic ligand and an aqua ligand act as bridges to the two nickel centres: the Ni-O(aquo)-N bond angle is 137.65(17)°. Each Ni centre is bonded to two nitrogens of the macrocycle, to a chelating acac unit, to an ethanol molecule as well as the bridging oxygen of the aqua group. The two nickel atoms sit outside the macrocycle cavity, such that the macrocyclic ligand acts as a canopy for the remainder of the dication. While none of the macrocycle oxygens are involved in the coordination to Ni, they are involved in internal hydrogen bonding with the aqua and ethanol ligands. Magnetic measurements show a paramagnetic behaviour down to 2 K, with an effective moment of 2.8 Bohr magnetons at room temperature.     

Monolysocardiolipins accumulate in Barth syndrome but do not lead to enhanced apoptosis

Barth syndrome (BTHS) is an X-linked recessive disorder that is biochemically characterized by low cellular levels of the mitochondrial phospholipid cardiolipin (CL). Previously, we discovered that the yeast disruptant of the TAZ ortholog in Saccharomyces cerevisiae not only displays CL deficiency but also accumulates monolysocardiolipins (MLCLs), which are intermediates in CL remodeling. Therefore, we set out to investigate whether MLCL accumulation also occurs in BTHS. Indeed, we observed MLCL accumulation in heart, muscle, lymphocytes, and cultured lymphoblasts of BTHS patients; however, only very low levels of these lysophospholipids were found in platelets and fibroblasts of these patients. Although the fatty acid composition of the MLCLs was different depending on the tissue source, it did parallel the fatty acid composition of the (remaining) CLs. The possible implications of these findings for the two reported CL remodeling mechanisms, transacylation and deacylation/reacylation, are discussed. Because MLCLs have been proposed to be involved in the initiation of apoptosome-mediated cell death by the sequestration of the proapoptotic protein (t)BH3-interacting domain death agonist (Bid) to the mitochondrial membrane, we used control and BTHS lymphoblasts to investigate whether the accumulation of MLCLs results in higher levels of apoptosis. We found no differences in susceptibility to death receptor-mediated apoptosis or in cellular distribution of Bid, cytochrome c, and other parameters, implying that MLCL accumulation does not lead to enhanced apoptosis in cultured BTHS lymphoblasts.     

Arterial vascularization of the mandible and maxilla of neotropical primates

The objective of the present investigation was to conduct a comparative macroscopic study of the arterial vascularization of the mandible and maxilla of neotropical primates of the genera Cebus, Alouatta, Callithrix, and Leontopithecus. After vinyl was injected into the arterial system of the head of each specimen, the pieces were macerated and corroded. The level of the bifurcation of the common carotid artery into the internal and external carotids varied between the first and third cervical vertebrae. The external carotid artery accounts for most of the vascularization of the facial structures. The actual vessels responsible for the supply of this region are the sublingual, facial, angular, lingual, submandibular, submental, inferior and superior labial, maxillary, inferior alveolar, infraorbital, superior posterior alveolar, palatine major, and sphenopalatine arteries. We conclude that although the arterial vascular pattern was similar in all the genera studied, and resembles the human pattern, there are notable variations in the vasculature of the mandible and maxilla among these four neotropical genera.     

Arylfurans as potential trypanosoma cruzi trypanothione reductase inhibitors

The natural lignans veraguensin and grandisin have been reported to be active against Trypanosoma cruzi bloodstream forms. Aiming at the total synthesis of these and related compounds, we prepared three 2-arylfurans and eight 2,5-diarylfurans. They were evaluated for their potential as T. cruzi trypanothione reductase (TR) inhibitors as well against the parasite's intracellular (amastigote) and bloodstream (trypomastigote) forms. Compound 12 was the most effective against TR with an IC50 of 48.5 microM while 7 and 14 were active against amastigotes, inhibiting the parasite development by 60% at 20 microg/ml (59 and 90 microM, respectively). On the other hand, none of the compounds was significantly active against the parasite bloodstream forms even at 250 microg/ml (0.6-1.5 mM).     

Measurement of carnitine biosynthesis enzyme activities by tandem mass spectrometry: differences between the mouse and the rat

Although the mouse frequently is used to study metabolism and deficiencies therein, little is known about carnitine biosynthesis in this animal. To this point, only laborious procedures have been described to measure the activity of carnitine biosynthesis enzymes using subcellular fractions as the enzyme source. We developed two simple tandem mass spectrometry-based methods to determine the activity of three carnitine biosynthesis enzymes (6-N-trimethyllysine dioxygenase, 4-trimethylaminobutyraldehyde dehydrogenase, and 4-trimethylaminobutyric acid dioxygenase) in total homogenates that can be prepared from frozen tissue. The new assays were used to characterize these enzymes in mouse liver homogenate. Because carnitine biosynthesis has been studied extensively in the rat, we compared the mouse tissue distribution of carnitine biosynthesis enzyme activities and levels of the biosynthesis metabolites with those in the rat to determine which tissues contribute to carnitine biosynthesis in these species. Surprisingly, large differences in enzyme activities were found between the rat and the mouse, whereas carnitine biosynthesis metabolite levels were very similar in both species, possibly due to the different kinetic properties of the first enzyme of carnitine biosynthesis. Also, muscle carnitine levels were found to vary considerably between these two species, suggesting that there is a metabolic dissimilarity between the mouse and the rat.     

In vitro anti-Neisseria gonorrhoeae activity of Terminalia macroptera leaves

We used the agar dilution method to evaluate the antibacterial effect of Terminalia macroptera leaf (Tml) extract against nine reference and clinical Neisseria gonorrhoeae strains, including penicillin- and tetracycline-resistant and -susceptible strains. Tml possesses anti-N. gonorrhoeae activity against all of the strains and the minimum inhibitory concentrations (MIC) were between 100 and 200 microg ml(-1). We then used a liquid-liquid partition method to divide the Tml extract into five fractions and determined the anti-N. gonorrhoeae activity of each of the fractions. All of the fractions showed antibacterial activity. The most active one was identified as the diethyl ether fraction and had MIC values of between 25 and 50 microg ml(-1) against all of the strains.     

Expression of clock genes in human subcutaneous and visceral adipose tissues

Disrupted circadian rhythms are associated with obesity and metabolic alterations, but little is known about the participation of peripheral circadian clock machinery in these processes. The aim of the present study was to analyze RNA expression of clock genes in subcutaneous (SAT) and visceral (VAT) adipose tissues of male and female subjects in AM (morning) and PM (afternoon) periods, and its interactions with body mass index (BMI). Ninety-one subjects (41 ± 11 yrs of age) presenting a wide range of BMI (21.4 to 48.6 kg/m(2)) were included. SAT and VAT biopsies were obtained from patients undergoing abdominal surgeries. Clock genes expressions were evaluated by qRT-PCR. The only clock gene that showed higher expression (p 相似文献   

Delineating the role of alterations in lipid metabolism to the pathogenesis of inherited skeletal and cardiac muscle disorders: Thematic Review Series: Genetics of Human Lipid Diseases

As the specific composition of lipids is essential for the maintenance of membrane integrity, enzyme function, ion channels, and membrane receptors, an alteration in lipid composition or metabolism may be one of the crucial changes occurring during skeletal and cardiac myopathies. Although the inheritance (autosomal dominant, autosomal recessive, and X-linked traits) and underlying/defining mutations causing these myopathies are known, the contribution of lipid homeostasis in the progression of these diseases needs to be established. The purpose of this review is to present the current knowledge relating to lipid changes in inherited skeletal muscle disorders, such as Duchenne/Becker muscular dystrophy, myotonic muscular dystrophy, limb-girdle myopathic dystrophies, desminopathies, rostrocaudal muscular dystrophy, and Dunnigan-type familial lipodystrophy. The lipid modifications in familial hypertrophic and dilated cardiomyopathies, as well as Barth syndrome and several other cardiac disorders associated with abnormal lipid storage, are discussed. Information on lipid alterations occurring in these myopathies will aid in the design of improved methods of screening and therapy in children and young adults with or without a family history of genetic diseases.