Algal Carotenoids 51. Secondary carotenoids 2.Haematococcus pluvialis aplanospores as a source of (3S, 3′S)-astaxanthin esters

Aplanospores ofHaematococcus pluvialis MUR 145 contained 0.7% carotenoids (dry wt. basis) consisting of β,β-carotene (5% of total carotenoid), echinenone (4%), canthaxanthin (4%), (3S,3′S)-astaxanthin diester (34%), (3S,3′S)-astaxanthin monoester (46%), (3S,3′S)-astaxanthin (1%) and (3R,3′R,6′R)-lutein (6%). The astaxanthin esters were examined by TLC and HPLC and VIS,¹H NMR and mass spectra recorded. Their chirality was determined by the camphanate method (Vecchi & Müller, 1979) after anaerobic hydrolysis. The tough cell wall of the aplanospores required enzymatic treatment prior to pigment extraction. The potential use of this microalga as a feed ingredient in aquaculture is discussed briefly.     

Lipid matrix plays a role in Abeta fibril kinetics and morphology

While neuronal membranes are proposed to be the primary target of amyloid plaques, the effect of phospholipids on fibril formation kinetics and morphology has not yet been resolved. We report that interaction of various compositions with neuronal mimics promoted different processes of fibril formation: negatively charged surfaces increased the lag time and elongation rate in thioflavin T assays, while brain total lipid extract had an opposite effect compared to that in the absence of lipid. Electron microscopy showed thin and elongated fibrils when the peptide was incubated with anionic lipids, while neutral surfaces promoted coarse and small fibrils. Circular dichroism and thioflavin T assays confirmed an initially unstructured peptide, and measured its transition to an aggregated beta-sheet conformation.     

Efficacy of a Brief Biofeedback Intervention on Mood,Arousal, Mental Workload,Movement Time,and Biofeedback Device Preference

Applied Psychophysiology and Biofeedback - Biofeedback (BF) training has been utilized with performers for years. Previous literature highlights the effectiveness of multi-week intervention...     

Infection with a novel gammaherpesvirus in northern elephant seals (Mirounga angustirostris)

Twenty juvenile northern elephant seals (Mirounga angustirostris) that died between 1998 and 2004 had ulcers on the tongue, palatine mucosa, and/or tonsils. Histologic examination of the lesions revealed cytoplasmic swelling, nuclear pyknosis, and eosinophilic to amphophilic intranuclear inclusions bodies suggestive of herpesviral infection. Electron microscopic examination and polymerase chain reaction analysis confirmed the presence of a herpesvirus. Subsequent DNA sequencing identified this to be a new gammaherpesvirus that was similar to Porcine lymphotropic virus 2, Alcephaline herpesvirus 1 (malignant catarrhal fever virus from wildebeest), and Chlorocebus rhadinovirus 1 from African green monkeys. Identical herpesviral DNA was also detected in blood and mucosal swabs collected from five healthy elephant seal pups.     

Functional characterization of Escherichia coli MsbA: interaction with nucleotides and substrates

The Escherichia coli MsbA protein is a 65-kDa member of the ATP-binding cassette superfamily. It is thought to function as an ATP-dependent lipid translocase that transports lipid A from the inner to the outer leaflet of the cytoplasmic membrane. MsbA with high ATPase activity was isolated and found to be homodimeric in detergent solution. The protein ATPase activity was inhibited by vanadate and showed variable patterns of stimulation and inhibition by lipid A and other compounds. The intrinsic tryptophan fluorescence of the protein was characterized, and dynamic quenching using acrylamide showed that a conformational change took place on binding of lipid A. Fluorescence quenching was used to characterize the interactions of MsbA with nucleotides and various putative substrates, including lipids, lipid-like compounds, and drugs. MsbA had an apparent binding affinity for ATP of approximately 2 mm and also bound nonhydrolyzable ATP analogs and fluorescent ATP derivatives. The putative substrate lipid A interacted with the protein with an affinity of 6.4 microm. Drugs that are known to be substrates for ABC multidrug transporters also interacted with MsbA with affinities in the range 0.25-50 microm. This study represents the first use of fluorescence approaches to estimate MsbA binding affinities for nucleotides and putative transport substrates.     

Interactions of the Australian tree frog antimicrobial peptides aurein 1.2, citropin 1.1 and maculatin 1.1 with lipid model membranes: differential scanning calorimetric and Fourier transform infrared spectroscopic studies

The interactions of the antimicrobial peptides aurein 1.2, citropin 1.1 and maculatin 1.1 with dimyristoylphosphatidylcholine (DMPC), dimyristoylphosphatidylglycerol (DMPG) and dimyristoylphosphatidylethanolamine (DMPE) were studied by differential scanning calorimetry (DSC) and Fourier-transform infrared (FTIR) spectroscopy. The effects of these peptides on the thermotropic phase behavior of DMPC and DMPG are qualitatively similar and manifested by the suppression of the pretransition, and by peptide concentration-dependent decreases in the temperature, cooperativity and enthalpy of the gel/liquid-crystalline phase transition. However, at all peptide concentrations, anionic DMPG bilayers are more strongly perturbed than zwitterionic DMPC bilayers, consistent with membrane surface charge being an important aspect of the interactions of these peptides with phospholipids. However, at all peptide concentrations, the perturbation of the thermotropic phase behavior of zwitterionic DMPE bilayers is weak and discernable only when samples are exposed to high temperatures. FTIR spectroscopy indicates that these peptides are unstructured in aqueous solution and that they fold into alpha-helices when incorporated into lipid membranes. All three peptides undergo rapid and extensive H-D exchange when incorporated into D(2)O-hydrated phospholipid bilayers, suggesting that they are located in solvent-accessible environments, most probably in the polar/apolar interfacial regions of phospholipid bilayers. The perturbation of model lipid membranes by these peptides decreases in magnitude in the order maculatin 1.1>aurein 1.2>citropin 1.1, whereas the capacity to inhibit Acholeplasma laidlawii B growth decreases in the order maculatin 1.1>aurein 1.2 congruent with citropin 1.1. The higher efficacy of maculatin 1.1 in disrupting model and biological membranes can be rationalized by its larger size and higher net charge. However, despite its smaller size and lower net charge, aurein 1.2 is more disruptive of model lipid membranes than citropin 1.1 and exhibits comparable antimicrobial activity, probably because aurein 1.2 has a higher propensity for partitioning into phospholipid membranes.     

Cytochrome P450: taming a wild type enzyme

Protein engineering of cytochrome P450 monooxygenases (P450s) has been very successful in generating valuable non-natural activities and properties, allowing these powerful catalysts to be used for the synthesis of drug metabolites and in biosynthetic pathways for the production of precursors of artemisinin and paclitaxel. Collected experience indicates that the P450s are highly 'evolvable' - they are particularly robust to mutation in their active sites and readily accept new substrates and exhibit new selectivities. Their ability to adapt to new challenges upon mutation may reflect the nonpolar nature of their active sites as well as their high degree of conformational variability.