HPLC-analysis of algal pigments: comparison of columns,column properties and eluents

The effects of columns (Nucleosil C₁₈ODS, MZ-PAH, YMC-PACK C₃₀), column properties (inner diameters of 4 mm, 3 mm and 2 mm, pore-width 10 nm and 30 nm) and eluents (methanol, acetonitrile, acetone, water) were tested on the separation of algal pigments. The length of columns was 250 mm and particle size was 5 μm. Flow rates and gradients were adjusted to optimize peak separation; remaining chromatographic conditions were kept constant. The resolution of chromatographic systems was tested with pigment standards and various algal cultures. Total flow rate and retention times decreased with decreasing inner diameter, whereas pressure, sensitivity and peak-width increased. Pore width had negligible effects on the chromatographic separation of pigments under the test conditions. Only with acetonitrile as eluent were all the taxonomically important pigments resolved adequately: zeaxanthin (Cyanophyceae), lutein (Chlorophyceae), fucoxanthin (Bacillariopyceae), alloxanthin (Cryptophyceae), peridinin (Dinophyceae).     

Localization of visual pigments within rhabdoms of the compound eye of Spodoptera exempta (Insecta,Noctuidae)

Summary In the noctuid moth Spodoptera exempta, the distribution of visual pigments within the fused rhabdoms of the compound eyes was investigated by electron microscopy. Each ommatidium regularly contains eight receptor cells belonging to three morphological types: one distal, six medial, and one basal cell (Meinecke 1981); four different visual pigments — absorption maxima at approximately 355, 465, 515, and 560 nm — are known to occur within the eye (Langer et al. 1979). The compound eyes were illuminated in situ by use of monochromatic light of different wavelengths. This illumination produced a wide scale of structural changes in the microvilli of the rhabdomeres of individual cells. Preparation of eyes by freeze-substitution revealed the structural changes in the rhabdomeres to be effects of light occurring in vivo.The degree of structural changes may be considerably different in rhabdomeres within the same ommatidium; it was found to depend on the wavelength and the duration of illumination, the intensity received by the ommatidia as well as the spectral sensitivity of the receptor cells. Therefore, it was possible to estimate the spectral sensitivities of the morphological types of receptor cells. Generally, all medial cells are green receptors and all basal cells red receptors; distal cells are blue receptors in about two-thirds of the ommatidia, while in the remaining third of them distal cells are sensitive to ultraviolet light.Supported by Deutsche Forschungsgemeinschaft, Sonderforschungsbereich 114 (Bionach)     

Investigations of the pigments fromCytophaga johnsonae Cy j1

Besides carotenoids a complex of flexirubin-type pigments was isolated from the gliding bacteriumCytophaga johnsonae Cy j1 and separated into 6 components, which partly containe chlorine. In spite of the fact that these components still consist of pigment mixtures, the gross structures of 18 new flexirubin-type pigments could be deduced by spectroscopic and chemical investigations. The results open insights into biosynthesis and structural variety of the flexirubins, the novel non-isoprenoid pigments recently found inFlexibacter elegans.Non-Standard Abbreviations FT Fourier transformation - HPLC high pressure liquid chromatography - M⁺ molecular ion - M/M resolution of mass spectrometer - mu mass units - t _R retention time - TLC thin layer chromatography Part 16: Investigations on metabolites of microorganisms. Part. XV: H. Achenbach, W. Kohl, H. Reichenbach: Die Hauptpigmente vonCytophaga johnsonae. Tetrahedron Lett.1977, 1061. Part XIV: H. Achenbach, J. Witzke: Totalsynthese des Flexirubindimethylethers. Angew. Chem.89, 198 (1977); Angew. Chem. Int. Ed. Engl.16, 191 (1977)     

Photosensory retinal pigments in Halobacterium halobium

In Halobacterium halobium, nicotine is known to block the synthesis of retinal. Cells grown in the presence of nicotine do not show any photophobic response. Addition of retinal₁ or retinal₂ restored the photophobic responses to light-increase in the UV and to light-decrease in the green-yellow part of the spectrum. The action spectra of the two retinal₂-photosystems were red-shifted by 15–20 nm, compared with the corresponding retinal₁ systems. We conclude that each of the two photosystems, PS 370 and PS 565, has its own photosensory pigment with retinal as the chromophoric group.     

机械损伤对9种水生植物叶片的影响

水生植物叶片的功能性状特征与陆生植物有所不同,同时叶脉类型也显著影响叶片的功能性状。本研究选取9种具有不同叶脉类型的水生植物,通过对叶脉进行直接损伤,分析叶片性状（形态、色素含量和叶绿素荧光指标）在叶脉受损后的变化程度与叶脉类型的关系。结果显示：具有平行脉的3种水生植物对叶脉损伤具有较强的耐受性;具羽状脉的4种植物主脉受损后显著抑制叶片生长,而侧脉受损的影响在不同物种间有所不同,具有物种特异性。本研究可为大型湖泊水生植物修复的水生物种筛选提供参考。     

The metabolic interactions between Paramecium bursaria Ehrbg. and Chlorella spec. in the Paramecium bursaria-symbiosis

In an organism (strain C 1/2 from Dr. P. R. Hayes, Leeds) regarded as a typical representative of the genus Flavobacterium, flexirubin-type pigments have been identified. The Flavobacterium pigments contain structural elements of both, the pigments of the genus Flexibacter and the pigments of the genus Cytophaga. As flexirubin-type pigments seem to have a rather restricted distribution among bacteria, and have formerly proved to be useful chemosystematic markers for the flexibacteria, this new observation may indicate that there is a relatively close phylogenetic relationship between this type of flavobacteria and the Cytophaga-Flexibacter group.     

Alloxan: A growth accelerator for a nitrogen-fixing blue-green alga

Effect of Alloxan was studied on a nitrogen-fixing blue-green alga: Westiellopsis prolifica in pure cultures. Concentrations of Alloxan, 10 g to 50 g/ml stimulate the growth of the alga and increase the chlorophyll, carotin and phycocyanin content of the cultures.     

Carotenoids of Phaffia rhodozyma, a red-pigmented fermenting yeast

The red-pigmented fermenting yeast Phaffia rhodozyma contains astaxanthin as the principal carotenoid pigment. Echinenone, 3-hydroxyechinenone and phoenicoxanthin were also isolated and identified; isocryptoxanthin and canthaxanthin were absent. Evidence is presented for a new carotenoid, 3-hydroxy-3′4′-didehydro-β,ψ-caroten-4-one. A possible biosynthetic scheme for the formation of astaxanthin in P. rhodozyma is suggested.     

Composés bromés de Rytiphlea tinctoria (Rhodophyceae)

Four aromatic bromo compounds have been isolated from the ethanolic extract of Rytiphlea tinctoria after treatment with diazomethane: 2,4-dibromo-1,3,5-trimethoxy-benzene,5,6,3′,5′-tetrabromo-3,4,2′,4′,6′-pentamethoxydiphenylmethane, 5,6-dibromo-3,4-dimethoxy-benzyl alcohol and its ethyl ether. In addition to sterols, amino acids, this extract also contains quinonoid bromo-pigments which could play a rôle in photosensitisation of chlorophylls, a rôle normally taken by the phycobilins, in other Rhodophyceae.     

斑块面积对干燥-复水条件下藓类植物生理活性的影响

干扰会导致生物结皮斑块破碎并退化。为明确生物结皮斑块破碎诱发生物结皮退化机理,以黄土丘陵区土生对齿藓(Didymodon vinealis)结皮为研究对象,研究了干燥-复水条件下,单株和直径1 cm、2 cm、3 cm、4 cm、5 cm的藓结皮斑块内土生对齿藓的干燥速率、渗透调节物质、丙二醛和光合色素含量等的变化,以期揭示干扰后生物结皮退化的生物学机理。结果表明(1)除单株外,干燥速率随斑块面积减小而增加,直径1 cm斑块内藓的干燥速率是直径5 cm的2倍。(2)反复干燥-复水25天后,直径小于5 cm的斑块内藓的可溶性糖、可溶性蛋白和叶绿素含量低于直径5 cm斑块内藓的含量,丙二醛含量随斑块面积变化无明显规律。(3)干燥速率与斑块面积、可溶性糖、可溶性蛋白及叶绿素含量均呈极显著负相关。以上结果表明,藓结皮斑块面积通过影响斑块内藓类植物干燥速率进而影响其渗透调节和光合作用能力。藓结皮斑块面积减小,藓类植物干燥速率增大,生理活性降低,是藓结皮斑块破碎诱发其退化的原因。研究从藓类植物生理的角度,阐明了干扰后藓类植物衰亡的生理学原因,为生物结皮的保护和管理提供了科学依据。