Water geochemistry and sedimentary pigments in northern Victoria Land lakes,Antarctica

Total concentrations of algal pigments, organic C, C, N, P and S were determined in surface sediments from the littoral zone of 21 lakes in ice-free areas of northern Victoria Land (Antarctica) with different climatic and environmental conditions. Concentrations of major ions and nutrients were also determined in water samples from the same lakes. The latter samples had extremely variable chemical compositions; however, all the lakes resulted oligotrophic. Pigment concentrations in surface sediments were comparable to those reported for other Antarctic lakes and lower than those in oligotrophic lakes at lower latitudes. Cyanophyta, Chlorophyta and Bacillariophyta were the main taxa identified. These taxa correspond to those reported in previous microscopy-based studies on Antarctic phytoplankton and phytobenthos. Discriminant Function Analysis and Canonical Correspondence Analysis of data indicate that the distribution of pigments in these Victoria Land lakes depends mainly on their geographical location (particularly the distance from the sea) and nutrient status.     

Relationship between sedimentary pigments and primary production: evidence from core analyses of twelve Italian lakes

A statistically significant correlation of the type y = ax^b between sedimentary plant pigments and contemporary algal primary production has been found in a study of the recent trophic evolution of twelve Italian lakes. The equation is used to assess baseline production levels in periods (50–70 years ago) when human influence was low.     

Measurement and interpretation of fluorescence polarisations in phospholipid dispersions

An instrument that measures the temperature dependence of fluorescence polarisation and intensity directly and continuously is described. The behaviour of four fluorescent probes bound to a number of well characterised model systems was then examined. The motional properties of the probes were determined from the polarisation and intensity data and were found to be sensitive to the crystallineliquid crystalline phase transitions in phospholipid vesicles of dimyristoyl and dipalmitoyl phosphatidylcholine. Binary mixture of dilauroyl and dipalmitoyl phosphatidycholine show lateral phase separation and in this system the probes partition preferentially into the more ‘fluid’ phase. In systems that have been reported to contain ‘short range order’ or ‘liquid clustering’, such as dioleoyl phosphatidylcholine and liquid paraffin, the motion of the probes was found to have anomalous Arrhenius behaviour consistent with the idea that homogeneous phases were not being sampled. The significance of these findings for the interpretation of the behaviour of fluorescent probes bound to natural membranes is discussed.     

Phylogenetic relationships within Pyrenodesmia sensu lato and the role of pigments in its taxonomic interpretation

Most lichens of the family Teloschistaceae (Ascomycota) produce yellow-orange-red anthraquinone pigments. However, the genus Pyrenodesmia encompasses species in which anthraquinones are absent and replaced by a gray pigment Sedifolia-gray. It was shown recently that these species are related to taxa with both anthraquinones and Sedifolia-gray (Caloplaca xerica group, C. haematites group, and C. cretensis) and to species with a brown pigment instead of both anthraquinones and Sedifolia-gray (C. demissa, C. obscurella, and C. reptans). Nevertheless, relationships between mentioned anthraquinone-containing and anthraquinone-lacking species remained unclear. In total, 8 DNA loci from 41 species were used here to resolve these uncertainties. We concluded that C. demissa, C. obscurella, and C. reptans are rather distant from the core of Pyrenodesmia, and we place them outside of Pyrenodesmia sensu lato. Within Pyrenodesmia sensu lato, three lineages were revealed and recognized on a generic level: the genus Pyrenodesmia sensu stricto (21 species), the genus Kuettlingeria (14 species), which is resurrected here, and the genus Sanguineodiscus (4 species), which is newly described here. The genus Pyrenodesmia includes taxa that never contain anthraquinones, but Sedifolia-gray. It matches with the former C. variabilis group. Taxa of the genera Kuettlingeria and Sanguineodiscus have anthraquinones in their apothecia and Sedifolia-gray in their thalli. The genus Kuettlingeria includes the former C. xerica group plus C. cretensis and C. diphyodes. The genus Sanguineodiscus includes the former C. haematites group and C. bicolor. The identity of Kuettlingeria (Caloplaca) diphyodes was clarified and the name Pyrenodesmia helygeoides was resurrected. Twenty-four new combinations were proposed.     

Structural aspects of acylated plant pigments: stabilization of flavonoid glucosides and interpretation of their functions

The enzymatic synthesis of acylated isoquercitrins was accomplished by the lipase-catalyzed transesterification with carboxylic acid vinyl esters as acyl donors in an organic solvent. The introduction of an acyl group into isoquercitrin improved its thermostability and light-resistivity. In particular, isoquercitrin p-coumarate was the most stable of all the acylated isoquercitrins tested.     

Measurement and interpretation of fluorescence polarisations in phospholipid dispersions.

An instrument that measures the temperature dependence of fluorescence polarisation and intensity directly and continuously is described. The behaviour of four fluorescent probes bound to a number of well characterised model systems was then examined. The motional properties of the probes were determined from the polarisation and intensity data and were found to be sensitive to the crystalline-liquid crystalline phase transitions in phospholipid vesicles of dimyristoly and dipalmitoly phosphatidylcholine. Binary mixture of dilauroyl and dipalmitoyl phosphatidylcholine show lateral phase separation and in this system the probes parition preferentially into the more 'fluid' phase. In systems that have been reported to contain 'short range order' or 'liquid clustering', such as dioleoyl phosphatidylcholine and liquid paraffin, the motion of the probes was found to have anomalous Arrhenius behaviour consistent with the idea that homogeneous phases were not being sampled. The significance of these findings for the interpretation of the behaviour of fluorescent probes bound to natural membranes is discussed.     

Measurement of Vitamin D metabolites: an international perspective on methodology and clinical interpretation

The International Quality Assessment Scheme for Vitamin D metabolites (DEQAS) was introduced in 1989. Initially, the aim was to improve the reliability of 25-hydroxyvitamin D (25-OHD) assays but the scheme was extended in 1997 to include 1,25-dihydroxyvitamin D (1,25(OH)(2)D). DEQAS has 95 members in 18 countries (January 2003). Five serum samples are distributed quarterly and participants are given up to 6 weeks to return their results for statistical analysis. The majority of participants use commercial kits for both analytes. A performance target was set by an advisory panel in 1997 and, at present, requires participants to get 80% or more of their results within +/-30% of the All-Laboratory Trimmed Mean (ALTM). The performance targets are under continual review. In 2003, 59% of participants met the target (cf. 52% in 2000). A questionnaire, distributed in January 2003, requested information on methods and the interpretation of results. Reference ranges varied but there was reasonable agreement on the 25-OHD concentrations below which Vitamin D supplementation was advised. A minority (22%) of respondents was unsure whether Vitamin D(3) or Vitamin D(2) was used to treat patients in their locality. The majority (52%) of assays for 1,25(OH)(2)D were done 'on demand' and others for apparently spurious reasons. Most respondents thought participation in DEQAS extremely important and the planned introduction of on-line reporting should enhance its value.     

Lipid pigments and aging

It is a short survey of lipid pigment formation in which the role of free radicals in the peroxidation of lipids is particularly stressed. The chemical structure of lipopigments and the role of the chemical moiety in histochemical reactions is shortly overviewed. A new aspect of age in the formation of lipopigments is brought to light. Finally the role of hypoxaemia and no-reflow phenomenon influencing the pigment formation is discussed.     

Monascus pigments

Monascus pigments (MPs) as natural food colorants have been widely utilized in food industries in the world, especially in China and Japan. Moreover, MPs possess a range of biological activities, such as anti-mutagenic and anticancer properties, antimicrobial activities, potential anti-obesity activities, and so on. So, in the past two decades, more and more attention has been paid to MPs. Up to now, more than 50 MPs have been identified and studied. However, there have been some reviews about red fermented rice and the secondary metabolites produced by Monascus, but no monograph or review of MPs has been published. This review covers the categories and structures, biosynthetic pathway, production, properties, detection methods, functions, and molecular biology of MPs.     

Measurement of airway wall blood flow in sheep by laser-Doppler flowmetry: interpretation and problems

We have used laser-Doppler flowmetry (LDF), a technique that detects movement of erythrocytes, to measure tracheal and bronchial wall blood flow in anesthetized open-chest sheep. LDF derives continuous measurements noninvasively, although fiber-optic bronchoscopy is necessary to introduce the LDF probe into the airways. The response of the LDF flow signals at four regions of the airway walls to varying bronchial arterial flow rates was examined in both live and dead sheep by cannulation and subsequent perfusion of the common bronchial artery at different flow rates by use of a roller pump. In the live sheep, variations in bronchial arterial blood flow resulted in variations in LDF signals in the principal bronchus and in lobar and segmental bronchi but not in the trachea. In the dead sheep, variations in bronchial arterial blood flow resulted in variations in LDF signals in all four regions. Within regions, the average response of the LDF signals to varying bronchial blood flow rates was approximately linear in both live and dead sheep, but considerable site-to-site variation in response was observed. In the live sheep, significant LDF signals were observed when the bronchial arterial flow was set to zero and when the bronchial artery was perfused with dextran solution, which would in theory be expected to produce no LDF signal. A small LDF signal was also detected under zero flow conditions in the dead sheep. These observations suggest that the LDF technique, in addition to detecting blood flow from the bronchial artery also detects background noise and/or collateral circulation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Bacterial pigments and their applications

Natural pigments sourced from ores, insects, plants and animals were the colorants used since prehistoric period. Synthetic dyes which took the place of natural pigments in the middle of 19th century still rule the field to the maximum extent in spite of its hazardous effect to humans, animals and environment. As an alternative to synthetic pigments, bacterial pigments due to their better biodegradability and higher compatibility with the environment, offer promising avenues for various applications. The industry is now able to produce some bacterial pigments for applications in food, pharmaceuticals, cosmetics and textiles. Extraction of bacterial pigments in relatively pure and concentrated forms is the main technological challenge. Optimization of fermentation process and the medium components are reported as key strategies for economic recovery of pigments. Research work needs to be carried out to formulate the fermentation media for each bacterial pigment on large scale by using economical and easily available sources for commercial process. Recent advances in synthetic biology, metabolic engineering efforts of bacteria will greatly expand the pigments that could be produced economically in sufficient amounts for industrial application. This review summarizes the current technology status and challenges, economics, novel strategies for production of bacterial pigments and metabolic engineering of bacteria with a focus on applications of bacterial pigments in food industry, pharmaceutical industry, dyeing as well as on other applications.     

Fly visual pigments difference in visual pigments of blowfly and dronefly peripheral retinula cells

Journal of Comparative Physiology A - The visual pigments of peripheral retinula cells in fly eyes have been investigated by microspectrophotometry in vivo. Since flies have a pupil mechanism...     

Stromal pigments and taxonomy of Hypoxylon

Stromal pigments extracted with ethyl acetate from a variety of Hypoxylon species were examined by thin-layer chromatography and the results are discussed in relation to the taxonomy of the genus. Most species exhibited constant and characteristic pigment band patterns which in some cases proved to be useful in identification.     

Chloroplast pigments and algal systematics

The chloroplast pigments of one typical representative (Pleurochloris magna) and two potential members (clone BSG Sticho and an isolate called Tunis) of the new class Eustigmatophyceae have been examined by modern methods including mass spectrometry. The three cultures all exhibited the same chloroplast pigments: Chlorophyll a, but no b or c, δ-carotene (I), canthaxanthin (II), violaxanthin (IIIa), and esterified vaucheriaxanthin (IVb) plus some free vaucheriaxanthin (IVa). Furanoid rearrangement of the epoxidic carotenoids complicated the analysis. The unique pigment complement hereby indicated for Eustigmatophyceae is clearly different from the pigment distribution patterns reported for Chlorophyceae and Xanthophyceae.     

Photointermediates of visual pigments

Much progress has been made in recent years toward understanding the interactions between various proteins responsible for visual transduction which are initiated by an activated state of visual pigments. However, the changes which take place in the visual pigments themselves to convert them to the activated state are more poorly understood. Many spectroscopic techniques have been applied to this problem in recent years and considerable progress has been made. A major goal of these efforts is to understand at which stages protein change occurs and to characterize its structural features. In the visual system evidence is accumulating, for example, that chromophore independent protein change begins immediately prior to lumirhodopsin formation. Considerable insight has been gained recently into the early intermediates of visual transduction and the stage is set to achieve similar understanding of the later intermediates leading to rhodopsin's activated state.