Chronic Artificial Blue-Enriched White Light Is an Effective Countermeasure to Delayed Circadian Phase and Neurobehavioral Decrements

Studies in Polar Base stations, where personnel have no access to sunlight during winter, have reported circadian misalignment, free-running of the sleep-wake rhythm, and sleep problems. Here we tested light as a countermeasure to circadian misalignment in personnel of the Concordia Polar Base station during the polar winter. We hypothesized that entrainment of the circadian pacemaker to a 24-h light-dark schedule would not occur in all crew members (n = 10) exposed to 100–300 lux of standard fluorescent white (SW) light during the daytime, and that chronic non-time restricted daytime exposure to melanopsin-optimized blue-enriched white (BE) light would establish an a stable circadian phase, in participants, together with increased cognitive performance and mood levels. The lighting schedule consisted of an alternation between SW lighting (2 weeks), followed by a BE lighting (2 weeks) for a total of 9 weeks. Rest-activity cycles assessed by actigraphy showed a stable rest-activity pattern under both SW and BE light. No difference was found between light conditions on the intra-daily stability, variability and amplitude of activity, as assessed by non-parametric circadian analysis. As hypothesized, a significant delay of about 30 minutes in the onset of melatonin secretion occurred with SW, but not with BE light. BE light significantly enhanced well being and alertness compared to SW light. We propose that the superior efficacy of blue-enriched white light versus standard white light involves melanopsin-based mechanisms in the activation of the non-visual functions studied, and that their responses do not dampen with time (over 9-weeks). This work could lead to practical applications of light exposure in working environment where background light intensity is chronically low to moderate (polar base stations, power plants, space missions, etc.), and may help design lighting strategies to maintain health, productivity, and personnel safety.     

Chemical and enzymological characterization of an indonesian variant of human erythrocyte carbonic anhydrase II,CAIIJogjakarta (17 Lys → Glu)

A new variant of human erythrocyte carbonic anhydrase II (CAII) was discovered in a single heterozygous individual during routine screening of blood samples from the island of Java in Indonesia. The normal and variant components of the heterozygous CAII mixture were resolved by isoelectric focusing following purification by a specific affinity matrix. Specific esterase activities and Michaelis-Menten constants were identical. Only very small differences were noted with respect to inhibition by acetazolamide and chloride. Double diffusion analysis showed the immunological identify of the normal and variant enzymes. The variant CAII was considerably less heat stable than the normal enzyme. The variant was slightly more stable than the normal enzyme upon dialysis against the zinc chelator dipicolinic acid (PDCA), indicating a tighter binding of zinc than the normal enzyme. Analysis of tryptic peptides from the normal and variant enzymes indicated that, in the variant, lysine at position 17 from the N terminus had changed to glutamic acid. The differences in physiochemical properties observed for the normal and variant enzyme are discussed in relation to the possible effects of this substitution on the structure of the CAII molecule.     

A glucoside of urospermal A

The aerial parts of Urospermum picroides afforded, in addition to urospermal A a p-hydroxylphenyl acetate of a glucoside of urospermal A.     

α-Chymotrypsin-Catalyzed Peptide Synthesis Using <Emphasis Type="Italic">N</Emphasis>-Protected <Emphasis Type="SmallCaps">D</Emphasis>-Amino Acid Carbamoylmethyl Esters as Acyl Donors

α-Chymotrypsin-catalyzed peptide synthesis was carried out between an N-protected D-amino acid ester and an L-amino acid amide (acyl donor, 10 mM; acyl acceptor, 50 mM; enzyme, 2 mg ml⁻¹; pH 8). By using a highly reactive carbamoylmethyl (Cam) ester as acyl donor, the D-amino acid was incorporated into the N-terminus of the resulting dipeptide amide. N-Protected dipeptide amides bearing D-amino acids such as D-Phe, D-Leu and D-Ala at their N-terminus were synthesized in high yields (up to 80%) in 1–3 h.     

Novel motifs in amino acid permease genes from Leishmania

Eight amino acid permease genes from the protozoan parasite Leishmania donovani (AAPLDs) were cloned, sequenced, and shown to be expressed in promastigotes. Seven of these belong to the amino acid transporter-1 and one to the amino acid polyamino-choline superfamilies. Using these sequences as well as known and characterized amino acid permease genes from all kingdoms, a training set was established and used to search for motifs, using the MEME motif discovery tool. This study revealed two motifs that are specific to the genus Leishmania, four to the family trypanosomatidae, and a single motif that is common between trypanosomatidae and mammalian systems A1 and N. Interestingly, most of these motifs are clustered in two regions of 50-60 amino acids. Blast search analyses indicated a close relationship between the L. donovani and Trypanosoma brucei amino acid permeases. The results of this work describe the cloning of the first amino acid permease genes in parasitic protozoa and contribute to the understanding of amino acid permease evolution in these organisms. Furthermore, the identification of genus-specific motifs in these proteins might be useful to better understand parasite physiology within its hosts.     

Preliminary evaluation of non-native rainbow trout (Oncorhynchus mykiss) impact on the Cederberg ghost frog (Heleophryne depressa) in South Africa’s Cape Fold Ecoregion

We evaluated the impact of non-native rainbow trout Oncorhynchus mykiss on a population of endemic Cedarberg ghost frog Heleophryne depressa in the upper Krom River (Olifants-Doring River Catchment, Cape Fold Ecoregion). We compared H. depressa abundance (using kick-sampling and underwater video analysis) and environmental conditions between sites above and below a waterfall that marks the upper distribution limit of O. mykiss. Heleophryne depressa abundance was significantly greater above the waterfall than that below it, and, because there was no significant difference in measured environmental variables, O. mykiss presence is identified as the most likely explanation for the observed decrease in H. depressa abundance.     

Immunolocalization of the saposin-like insert of plant aspartic proteinases exhibiting saposin C activity. Expression in young flower tissues and in barley seeds

The plant-specific insert (PSI) of cypro11 gene-encoding cyprosin, an aspartic proteinase from Cynara cardunculus , has been cloned by polymerase chain reaction (PCR) into a bacterial expression vector. A rearranged form of this PSI in which the N- and C-terminal sequences were permutated to make it more similar to the structural arrangement observed in saposins was also cloned and expressed in the same system. The biological activities of the two purified recombinant proteins were compared to those of human saposins B and C. The proteins showed similar activity to saposin C, i.e. capacity to activate human glucosylceramidase. At a concentration of 5 µ M , wild-type PSI, saposin C, and rearranged PSI activated human glucosylceramidase two-, three-, and five-fold, respectively. The K_m for 4-methylumbelliferyl β-glucopyranoside was around 7 µ M in the presence of any of the three activators (5 µ M ). The neurotropic activity using NS20Y cells and lipid-binding properties of the plant recombinant proteins were tested. The two plant proteins showed lipid-binding properties similar to those of saposins but did not have any effect on neurite outgrowth. Immunolocalization of PSI showed its expression in protective tissues in flower meristem – protodermis, in C. cardunculus and embryonic root cap and coleorhiza in mature barley grains – as well as husk, pericarp, and the aleurone layer. Possible biological functions suggested for the plant homologue to saposins besides the general activation of enzymes involved in lipid metabolism would be involvement in plant defence.     

Plant growth and mineral content of barley as related to irrigation with bicarbonate Waters

Summary In lysimeters filled with sand from the Wadi el Natrun Area, the effect of varying levels of bicarbonate in irrigation solutions on the growth and mineral content of barley, var. Maryut, was investigated.Crop yield decreased progressively with the bicarbonate ion level and this condition was associated with symptoms of chlorosis. The bicarbonate levels of 13.0 and 20.0 me/l developed almost similar effects and reduced the crop yield by about 60 per cent of the control. The 41 me/l bicarbonate level developed stunted plant growth, induced severe chlorosis and reduced crop yield by 70 per cent of the control.Mineral analysis of the whole plant tissue and cell sap reflected the treatment effect on the concentration of the nutritive elements. The data indicated the immobilization of iron particularly in the root part. The ratio of phosphorus to iron and calcium to iron in the cell sap increased greatly with the bicarbonate level in irrigation solutions and were related to chlorosis.     

Stimulation of hepatic cholesterol biosynthesis by fatty acids. Effects of oleate on cytoplasmic acetoacetyl-CoA thiolase, acetoacetyl-CoA synthetase and hydroxymethylglutaryl-CoA synthase.

The effects of oleic acid on the activities of cytosolic HMG-CoA (3-hydroxy-3-methylglutaryl-CoA) synthase, AcAc-CoA (acetoacetyl-CoA) thiolase and AcAc-CoA synthetase, as well as microsomal HMG-CoA reductase, all enzymes in the pathway of cholesterol biosynthesis, were studied in the isolated perfused rat liver. Oleic acid bound to bovine serum albumin, or albumin alone, was infused for 4 h at a rate sufficient to sustain an average concentration of 0.61 +/- 0.05 mM fatty acid during the perfusion. Hepatic cytosol and microsomal fractions were isolated at the termination of the perfusion. Oleic acid simultaneously increased the activities of the cytosolic cholesterol-biosynthetic enzymes 1.4-2.7-fold in livers from normal fed rats and from animals fasted for 24 h. These effects were accompanied by increased net secretion by the liver of cholesterol and triacylglycerol in the very-low-density lipoprotein (VLDL). We confirmed the observations reported previously from this laboratory of the stimulation by oleic acid of microsomal HMG-CoA reductase. In cytosols from perfused livers, the increase in AcAc-CoA thiolase activity was characterized by an increase in Vmax. without any change in the apparent Km of the enzyme for AcAc-CoA. In contrast, oleic acid decreased the Km of HMG-CoA synthase for Ac-CoA, without alteration of the Vmax. of the enzyme. The Vmax. of AcAc-CoA synthetase was increased by oleic acid, and there was a trend towards a small increase in the Km of the enzyme for acetoacetate. These data allow us to conclude that the enzymes that supply the HMG-CoA required for hepatic cholesterogenesis are stimulated, as is HMG-CoA reductase, by a physiological substrate, fatty acid, that increases rates of hepatic cholesterol synthesis and cholesterol secretion. Furthermore, we suggest that these effects of fatty acid on hepatic cholesterol metabolism result from stimulation of secretion of triacylglycerol in the VLDL by fatty acids, and the absolute requirement of cholesterol as an important structural surface component of the VLDL necessary for transport of triacylglycerol from the liver.     

Crystallization and preliminary investigation of single crystals of deoxyuridine triphosphate nucleotidohydrolase from Escherichia coli

Deoxyuridine triphosphate nucleotidohydrolase (dUTPase), an enzyme in the nucleotide metabolism that is a pyrophosphatase hydrolyzing dUTP, has been crystallized. The crystals belong to the trigonal space group R3 and diffract beyond 2 A. The native dUTPase crystals and a mercury derivative are stable in the X-ray beam and are suitable for a high resolution X-ray structure analysis.