Optically active Ru(II) complexes with a chiral Tröger's base ligand and their interactions with DNA

Three stereoisomers of a Ru(II) complex bearing a chiral bis-phenanthroline Tr?ger's base analogue, TBphen2 (1), have been isolated from the reaction of the enantiomerically pure precursor complex Lambda- (or Delta-) cis-[Ru(phen)2(py)2]2+ (phen=1,10-phenanthroline, py=pyridine) with the racemic mixture of 1. Each stereoisomer of [Ru(phen)2TBphen2]2+ (2) has been characterized by 1H NMR and CD spectroscopy. Electrochemical studies revealed that the redox properties of 2 are not influenced by the stereochemistry, however, the electrochemical oxidation of the metallic center is irreversible because of the diazocine bridge of the TBphen2 ligand. Steady-state emission measurements in the presence of calf thymus DNA showed that the DNA binding of [Ru(phen)2TBphen2]2+ depends on the stereoisomer and is mainly controlled by the absolute configuration of the metal center of the complex. The affinity constant for the stereoisomer Delta-S-2 is 10(2) higher than that for Lambda-S-2 and rac-[Ru(phen)3]2+.     

Eicosapentaenoic and docosahexaenoic acids production by and okara-utilizing potential of thraustochytrids

Nine thraustochytrid strains isolated from subtropical mangroves were screened for their eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) production potential in a glucose yeast extract medium. Their ability to utilize okara (soymilk residue) for growth and EPA and DHA production was also evaluated. EPA yield was low in most strains, while DHA level was high on glucose yeast extract medium, producing 28.1–41.1% of total fatty acids, for all strains, with the exception of Ulkenia sp. KF13. The DHA yield of Schizochytrium mangrovei strains ranged from 747.7 to 2778.9 mg/l after 52 h of fermentation at 25°C. All strains utilized okara as a substrate for growth, but DHA yield was lower when compared with fermentation in a glucose yeast extract medium. Journal of Industrial Microbiology & Biotechnology (2001) 27, 199–202. Received 11 December 2000/ Accepted in revised form 29 June 2001     

Early handling modulates outcome of neonatal dexamethasone exposure

Synthetic glucocorticoids such as dexamethasone (DEX) are used to prevent or treat respiratory disorders in prematurely born infants. Besides the short-term benefit on lung development, numerous human and animal studies have reported adverse neurodevelopmental side effects. In contrast, maternal care is known to exert a positive influence on neurodevelopmental outcome in rodents. The aim of the current study was therefore to investigate whether neonatal handling (days 1–21), known to induce maternal care, might serve as an intervention strategy modulating the adverse effects of DEX treatment (days 1–3). For this purpose we have measured the outcome of these early-life manipulations on development as well as adult endocrine and behavioral phenotype of male rats. Maternal care was observed during the first week of life and indeed enhanced in response to handling. Eye opening was accelerated and body weight reduced in DEX-treated animals. In adulthood, we report that handling ameliorated impaired spatial learning observed in DEX treated non-handled animals in the T-maze. Additionally, handling reduced susceptibility to the impact of DEX treatment in the water maze. Although DEX treatment and handling both resulted in enhanced negative feedback of the stress-induced corticosterone response and both reduced startle reactivity, the acquisition of fear was only reduced by handling, without effect of DEX. Interestingly, handling had a beneficial effect on pre-pulse inhibition, which was diminished after DEX treatment. In conclusion, these findings indicate that handling of the neonate enhances maternal care and attenuates specific DEX-induced alterations in the adult behavioral phenotype.     

Respiratory Evolution Facilitated the Origin of Pterosaur Flight and Aerial Gigantism

Pterosaurs, enigmatic extinct Mesozoic reptiles, were the first vertebrates to achieve true flapping flight. Various lines of evidence provide strong support for highly efficient wing design, control, and flight capabilities. However, little is known of the pulmonary system that powered flight in pterosaurs. We investigated the structure and function of the pterosaurian breathing apparatus through a broad scale comparative study of respiratory structure and function in living and extinct archosaurs, using computer-assisted tomographic (CT) scanning of pterosaur and bird skeletal remains, cineradiographic (X-ray film) studies of the skeletal breathing pump in extant birds and alligators, and study of skeletal structure in historic fossil specimens. In this report we present various lines of skeletal evidence that indicate that pterosaurs had a highly effective flow-through respiratory system, capable of sustaining powered flight, predating the appearance of an analogous breathing system in birds by approximately seventy million years. Convergent evolution of gigantism in several Cretaceous pterosaur lineages was made possible through body density reduction by expansion of the pulmonary air sac system throughout the trunk and the distal limb girdle skeleton, highlighting the importance of respiratory adaptations in pterosaur evolution, and the dramatic effect of the release of physical constraints on morphological diversification and evolutionary radiation.     

Functional characterization of an androgen response element in the first intron of the C3(1) gene of prostatic binding protein

We demonstrate that the 204 bp intronic gene fragment of C3(1), which has a specific in vitro affinity for the androgen receptor, is able to confer androgen responsiveness to a heterologous promoter. This characteristic is completely destroyed by a single G----T substitution, affecting a 5'-TGTTCT-3' element that closely resembles the consensus sequence of the glucocorticoid and progesterone response elements (GRE/PRE). In fact we could show that this androgen response element (ARE) also acts as a similarly weak GRE or PRE in T-47D cells.     

Evaluation of the Influence of Cardiorespiratory Fitness on Diverse Health Risk Factors,Independent of Waist Circumference,in 40‐Year‐Old Flemish Males

Objective: To examine whether cardiorespiratory fitness is associated with health risk factors, independent of abdominal obesity (waist circumference). Research Methods and Procedures: Data from 141 40‐year‐old Flemish male subjects were used in a cross‐sectional design. The main outcome measure in this study was the health risk profile, composed of lipid parameters, blood pressure, and body composition parameters. Data were analyzed by regression analysis and by means of analysis of covariance with waist circumference (WC) as covariate and cardiorespiratory fitness as source of variance. Results: The data demonstrated that cardiorespiratory fitness was significantly associated with triglycerides, with the ratio of total cholesterol/serum high density lipoprotein cholesterol, and with percent body fat, independent of an association with WC. Discussion: Major findings of the present cross‐sectional study indicate that a high WC is associated with adverse health‐related lipid profile and body composition characteristics and that relatively high levels of aerobic fitness attenuate the health risk associated with a large WC.     

Nuclear magnetic resonanceimaging of membrane permeability changes in plants during osmoticstress

The cell water balance of maize (Zea mays L., cv LG 11) andpearl millet (Pennisetum americanum L., cv MH 179) duringosmotic stress was studied non‐invasively using ¹H nuclearmagnetic resonance (NMR) microscopy. Single NMR parameter imagesof (i) the water content (ii) the transverse relaxation time (T₂)and (iii) the apparent diffusion coefficient (D_app)were used to follow the water status of the stem apical region duringosmotic stress. During stress there are hardly any changes in watercontent or T₂ of the stem region of maize. Incontrast, the apical tissue of pearl millet showed a ～ 30% decreaseof T₂ within 48 h of stress, whereasthe water content and D_app did not change. Thesechanges can be explained by an increase of the membrane permeabilityfor water. This conclusion is supported by results from scanningelectron microscopy, relaxation measurements of sugar solutionsand numerical simulations of the relaxation and (apparent) diffusionbehaviour of water in a plant cell.