Polysaccharides of Algae: 55. Polysaccharide Composition of Several Brown Algae from Kamchatka

A new spectrophotometric procedure was developed for the quantitative determination of fucoidan and alginic acid and used for their analysis in extracts from biomass of 17 species of brown algae collected from coastal waters of the Kamchatka peninsula. In addition, neutral monosaccharides and mannitol were determined in the hydrolysis products of the alga biomass samples. The polysaccharide composition was shown to substantially depend on the algal species. The alginic acid content was maximal in the Alaria marginatablades; all the other representatives of the order Laminariales also are useful sources of this polysaccharide. At the same time, the fucoidan content is rather low in Laminariales. The highest content of fucoidan was found in Saundersella simplex, but Chordaria flagelliformisand Fucus evanescensare more practical fucoidan sources; the available supplies and the sugar composition make the latter alga the most suitable for the complex processing to prepare mannitol, fucoidan, and alginic acid.     

Identification of the Channelrhodopsin Genes in the Green and Cryptophytic Algae from the White and Black Seas

Biochemistry (Moscow) - Due to the unique capability of modulating cell membrane potential upon photoactivation, channelrhodopsins of green (Chlorophyta) and cryptophytic (Cryptophyta) algae are...     

褐藻叶绿体的制备

在4℃条件下,采用CaCl₂溶液浸泡褐藻裙带菜（Undaria pinnatifida）的叶状体,观察CaCl₂溶液的浓度和浸泡时间对裙带菜叶绿体提取率及其荧光特性的影响.结果表明,裙带菜的叶状体经过CaCl₂溶液浸泡后,其叶绿体的提取率有明显地提高.根据裙带菜叶绿体的提取率和室温荧光发射光谱的测定结果,认为最适的方法是采用0.2 mol/L的CaCl₂溶液浸泡10 min.在这种条件下,裙带菜叶绿体的提取率是传统制备方法的5倍.室温荧光发射光谱的测定结果说明叶绿体的完整性较好.     

管藻目绿藻叶绿素蛋白复合物特性及比较研究

采用温和的ＰＡＧＥ法从管藻目刺松藻（Ｃｏｄｉｕｍ ｆｒａｇｉｌｅ （Ｓｕｒ．）Ｈａｒｉｏｔ）和假根羽藻（Ｂｒｙｏｐｓｉｓ ｃｏｒｔｉｃｕｌａｎｓ Ｓｅｔｃｈ．）,丝藻目绿藻软丝藻（Ｕｌｏｔｈｒｉｘ ｆｌａｃｃａ （Ｄｉｌｌｗ．）Ｔｈｕｒ．）,及菠菜（Ｓｐｉｎａｃｉａ ｌｏｅｒａｃｅａ Ｍｉｌｌ．）中分别得到１１、１１、７和９种色素蛋白复合物,对复合物的多种特性,包括分子量、Ｃｈｌ ａ／ｂ比值、叶绿     

管藻目绿藻叶绿素蛋白复合物特性及比较研究

By mild PAGE method, 11, 11, 7 and 9 chlorophyll-protein complexes were isolated from two species of siphonous green algae (Codium fragile (Sur.) Hariot and Bryopsis corticulans Setch.), green alga (Ulothrix flacca (Dillw.) Thur.), and spinach (Spinacia oleracea Mill.), respectively. Apparent molecular weights, Chl a/b ratios, distribution of chlorophyll, absorption spectra, low temperature fluorescence spectra of these complexes were determined, and compared with one another. PSⅠ complexes of two siphonous green algae are larger in apparent molecular weight because of the attachment of relative highly aggregated LHCⅠ. Four isolated light-harvesting complexes of PSⅡ are all siphonaxanthin-Chl a/b-protein complexes, and they are not monomers and oligomers like those in higher plants. Especially, the absence of 730 nm fluorescence in PSⅠ complexes indicates a distinct structure and energy transfer pattern.     

绿色、棕色和白色棉品种光合作用与产量性状的研究

以棕色棉(皖棉38号)、绿色棉(皖棉39号)和白色棉(皖棉25号)为材料,研究了它们的光合表现与产量性状.结果表明:与白色棉相比,彩色棉皖棉38号和绿色棉皖棉39号中前期干物质积累速率慢、积累量少;叶绿素含量低;叶面积系数的增长主要在棉花生育中前期,盛花期以后,叶面积系数下降较快;光合速率在盛花前期略高于白色棉,但盛花...     

Prospects for the Use of Commercial and Potentially Commercial Brown Algae of the Far Eastern Seas as a Source of Polyphenols

Russian Journal of Marine Biology - The properties of polyphenol extracts from marine brown algae of the families Laminariaceae, Alariaceae, Arthrothamnaceae, Costariaceae, Сystoseiraceae,...     

Immunofluorescence Study of Microtubule Organization in Some Polarized Cell Types of Selected Brown Algae

The microtubule (Mt) organization in apical cells of Sphacelaria rigidula. as well as in branch initials of S. rigidula and Ectocarpus siliculosus, was studied by immunofluorescence. The apical interphase cells of S. rigidula show an impressive cytoskeleton of Mts, converging on the centrosome(s). A number of Mt bundles are perinuclear, but most of them run in axial orientation from the centrosomes to the cell cortex. The anterior Mt system consists of numerous thin Mt bundles, whereas the posterior system contains fewer and thicker bundles. In cells entering prophase, the cytoplasmic Mts gradually disappear. This process is somewhat faster at the posterior than at the anterior pole of the premitotic nucleus. After mitosis, the cytoplasmic Mts of the apical region appear to be re-organized more rapidly than those of the basal part of the cell. The apical daughter nucleus retains a lobed shape and condensed chromatin for a longer time, and increases considerably in size between telophase and cytokinesis, compared to the basal one. Duplication of the centrosomes proceeds more rapidly in the anterior region of apical cells than in the basal part. During branch formation in S. rigidula and E. siliculosus, a new polarity axis is established, and the Mts extend towards the protrusion into which the nucleus migrates before mitosis. After nuclear division, one of the daughter nuclei is positioned at the tip of the branch, where the apical Mt focussing point is localized.     

Physical–Chemical Properties,Physiological Activity,and Usage of Alginates,the Polysaccharides of Brown Algae

This review summarizes data on alginates, polysaccharides isolated from brown algae. Their raw sources, chemical structure, and physical–chemical properties are discussed briefly. This paper is mainly focused on the physiological activity and usage of alginates in food and pharmaceutical industries. The data on alginate toxicity and necessary safety measures are also presented. The capability of alginates to bind and eliminate heavy metals and radionuclides from animal and human organisms is discussed. This paper also deals with the effects of alginates on the metabolism of lipids, carbohydrates, etc., and their usage in medicine, dietetics, and biotechnology.     

Uptake of Zinc and Strontium by Brown Algae

The accumulation of radioactively labelled strontium and zinc by living and killed tips of the brown alga Ascophyllum nodosum (L.) Le Jol. was studied and compared with the uptake in some model substances. The accumulation of strontium was reversible, and similar in living and killed plants. Equilibrium was established within a couple of days. Strontium accumulation seemed to be an ionexchange process involving the negatively charged intercellular polysaccharides, probably mainly alginate. Only a small fraction of the zinc uptake in living algae seemed to be due to a similar ion exchange with the intercellular polysaccharides. The characteristic features of the zinc uptake was a constant, slow, irreversible accumulation persisting for very long periods of time. In dead algae the uptake was rapid and reversible, indicating that the algae contained zinc-binding substances which were not directly accessible to the zinc ions in the surrounding seawater before killing. It is proposed that these substances in the living plant are contained in membrane-surrounded structures, probably vacuoles. These membranes, effectively regulating the zinc uptake in the living cells, are destroyed by killing, making the zinc binding substances directly accessible. The transfer of zinc from the reversible intercellular sites to the irreversible cellular sites continued undisturbed during low-tide periods. The intercellular charged polysaccharides thus function as ion buffers, allowing ion uptake into the cell at a constant rate, independent of the tidal movements.     

Comparative Secretome Analyses of Primary Murine White and Brown Adipocytes Reveal Novel Adipokines

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Highlights

• •First comparative proteomic analysis of white and brown adipocyte secretomes.
• •100 novel adipokines differentially secreted from white versus brown adipocytes.
• •Functionally enriched protein class changes in white and brown adipocytes.
• •200 novel, NE-responsive adipokines from brown adipocytes.

     

Some New and Rare Freshwater Algae from Iraq

One new species of Sphaeroplea (S. bourrellyii Islam), and six taxa, hitherto unrecorded from Iraq, namely, Dichotomosiphon tuberosus (A. Br.) Ernst, Johannesbaptistia pellucida (Dickie) Taylor & Drouet, Microcoleus chthonoplastes Thuret ex Gomont, M. lacustris (Rab.) Farlow, Gloeotrichia longiarticulata G. S. West, and Ammatoidea (?) normanni W. & G. S. West are described and illustrated.     

Aspartate Kinase from Some Higher Plants and Algae

Regulation of aspartate kinase activity was examined in some higher plant seedlings (Helianthus annuus, Raphanus sativus, Cucutnis sativus, Sinapis alba), a green (Chlorellapyrenoidosa), and a blue-green alga (Anacystis nidulans). In Cucumis sativus a concerted feedback regulation by L-lysine and L-threonine was indicated. In all the other species examined, aspartate kinase was inhibited by both L-lysine and L-threonine and it depended upon the species which of them was the strongest inhibitor. Only slight effects of L-leucine, L-isoIeucine and L-valine were observed, except in the Sinapis alba enzyme.     

海藻肽的化学结构特征和活性作用研究进展

海藻中的肽类化合物具有显著的生物活性和药理作用,对其氨基酸序列及活性作用的研究已经取得了一些重要进展。发现的海藻肽类化合物并确定其化学结构式的主要有二肽、环肽和脂肽,这些肽类化合物具有抗肿瘤、降血压、降血脂、抗凝血、促进神经细胞分化、抗氧化、抗菌和抗病毒等生物活性。预测海藻肽类化合物在疑难病症的治疗上将发挥重要作用。     

Comparative Analysis of the Chemical Composition of Mixed and Pure Cultures of Green Algae and Their Decomposed Residues by 13C Nuclear Magnetic Resonance Spectroscopy

It is known that macromolecular organic matter in aquatic environments, i.e., humic substances, is highly aliphatic. These aliphatic macromolecules, predominantly paraffinic in structure, are prevalent in marine and lacustrine sediments and are believed to originate from algae or bacteria. A comparative study of mixed and pure cultures of green algae and their decomposed residues was performed by using solid-state ¹³C nuclear magnetic resonance spectroscopy as the primary analytical method. Results obtained in this study confirm the presence of components that are chemically refractory and that are defined as alghumin and hydrolyzed alghumin. These were detected in heterogeneous, homogeneous, and axenic biomasses composed of several genera of Chlorophyta. Although the chemical composition of algal biomass varied with culture conditions, the chemical structure of the alghumin and hydrolyzed alghumin, demonstrated by ¹³C nuclear magnetic resonance spectroscopy appeared to be constant for members of the Chlorophyta examined in this study. The alghumin was dominated by carbohydrate-carbon, with minor amounts of amide or carboxyl carbon and paraffinic carbon, the latter surviving strong hydrolysis by 6 N HCI (hydrolyzed alghumin). Bacterial decomposition of heterogeneous algal biomass labeled with ¹³C was conducted under both aerobic and anaerobic conditions to determine chemical structure and stability of the refractory material. The refractory fraction ranged from 33% in aerobic to 44% in anaerobic cultures. The refractory fraction recovered from either aerobic or anaerobic degradation comprised 40% alghumin, which represented an enrichment by 10% relative to the proportion of alghumin derived from whole cells of algae. The paraffinic component in the hydrolyzed alghumin of whole algal cells was found to be 1.8% and increased to 5.1 and 6.9% after aerobic and anaerobic bacterial degradation, respectively. It is concluded that members of the Chlorophyta contain a common insoluble structure composed of paraffinic carbon that is resistant to chemical and bacterial degradation under conditions used in this study. The paraffinic structure is identical to those constituting humin of aquatic origin. Thus, alga-derived macromolecular compounds deposited in aquatic environments (alghumin) probably contribute to sedimentary humic substances.     

Isolation and Culture of a Marine Bacterium Degrading the Sulfated Fucans from Marine Brown Algae

Fucoidans are matrix polysaccharides from marine brown algae, consisting of an α-l-fucose backbone substituted by sulfate-ester groups and masked with ramifications containing other monosaccharide residues. In spite of their interest as biologically active compounds in a number of homologous and heterologous systems, no convenient sources with fucanase activity are available yet for the degradation of the fucalean algae. We here report on the isolation, characterization, and culture conditions of a bacterial strain capable of degrading various brown algal fucoidans. This bacterium, a member of the family Flavobacteriaceae, was shown to secrete fucoidan endo-hydrolase activity. An extracellular enzyme preparation was used to degrade the fucoidan from the brown alga Pelvetia canaliculata. End products included a tetrasaccharide and a hexasaccharide made of the repetition of disaccharidic units consisting of α-1→3-l-fucopyranose-2-sulfate-α-1→4-l-fucopyranose-2,3-disulfate, with the 3-linked residues at the nonreducing end.     

非洲加纳籽生物学特性及其化学成分(综述)

现代植物化学研究发现,非洲加纳籽的主要化学成分为5-羟基色氨酸;现代药理研究表明,该植物具有抗抑郁、抑制肥胖和抗氧化等各种药理活性。本文系统介绍非洲加纳籽的生物学特性及化学成分与药理药效的国内外研究进展,为其引种驯化与深度开发提供理论依据。     

Lipid Composition of Novel Shewanella Species Isolated from Far Eastern Seas

A comparative study of the lipid composition of 26 strains (including type strains) of marine Gammaproteobacteria belonging to the genera Shewanella, Alteromonas, Pseudoalteromonas, Marinobacterium, Microbulbifer, and Marinobacter was carried out. The bacteria exhibited genus-specific profiles of ubiquinones, phospholipids, and fatty acids, which can serve as reliable chemotaxonomic markers for tentative identification of new isolates. The studied species of the genus Shewanella were distinguished by the presence of two types of isoprenoid quinones, namely, ubiquinones Q-7 and Q-8 and menaquinones MK-7 and MMK-7; five phospholipids typical of this genus, namely, phosphatidylethanolamine (PE), phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), lyso-PE, and acyl-PG; and the fatty acids [15:0, 16:0, 16:1 (n-7), 17:1 (n-8), i-13:0, and i-15:0]. The high level of branched fatty acids (38–45%) and the presence of eicosapentaenoic acid (4%) may serve as criteria for the identification of this genus. Unlike Shewanella spp., bacteria of the other genera contained a single type of isoprenoid quinone: Q-8 (Alteromonas, Pseudoalteromonas, Marinobacterium, and Microbulbifer) or Q-9 (Marinobacter). The phospholipid compositions of these bacteria were restricted to three components: two major phospholipids (PE and PG) and a minor phospholipid, bisphosphatidic acid (Alteromonas and Pseudoalteromonas) or DPG (Marinobacterium, Microbulbifer, and Marinobacter). The bacteria exhibited genus-specific profiles of fatty acids.     

Comparison of Microstructure of White Winter Fur and Brown Summer Fur of Some Arctic Mammals

Abstract Several species of Arctic mammals have brown hair in the summer and molt into a white pelage in the winter. It is unknown whether characteristics other than color of the hair also change during the color transition between seasons. We borrowed guard hair samples from museums to represent summer and winter pelages of five species: Alopex lagopus (Arctic fox), Lepus americanus (snowshoe hare), Lepus Arcticus (Arctic hare), Mustela erminea (ermine) and Mustela nivalis (least weasel). Micro-structural differences exist between the brown and white hairs. In general, white winter hairs had larger upper shaft medullas comprising more air-filled cells and smaller lower shafts. These structural changes may function in conservation of heat or in increasing light reflection to whiten the fur and aid as camouflage. © 1997 Published by Elsevier Science Ltd on behalf of The Royal Swedish Academy of Sciences.     

Emission of Volatiles From Brown Boronia Flowers: Some Comparative Observations

Extensive research has focused on the concentration of aglyconeswithin brown boronia (Boronia megastigma) flowers, however emissionof volatiles into the headspace above these flowers is not welldocumented. Using solid-phase microextraction (SPME) to trapvolatiles and GCMS analysis, we observed 23 volatiles in theheadspace above buds and flowers throughout flower maturation,above dissected floral organs and above whole plants held for36 h under either continuous light, continuous dark or 12 hlight:12 h dark:12 h light treatments. Fully-opened flowersemitted the most complex mixture of volatiles and in the greatestquantity, with a rapid decline in senescent flowers. Caryophyllene,humulene and bicyclogermacrene declined as flower buds matured;ß-ionone increased. From the individual floral organs,emission from the petaline anthers comprised 38% of total emissionsfrom the (calculated) ‘whole flower’, with 27% contributedby the petals and 10.5% by the stigma. Monoterpenes dominatedthe headspace from the calyx; dodecyl acetate, methyl jasmonateand (Z)-n-heptadec-8-ene were relatively predominant in emissionsfrom the androecium. ß-Ionone, the major floral volatilein brown boronia, dominated volatiles emitted from the stigma(87%). However, the relatively tiny petaline anthers, activein pollen production and high in carotenoids, contributed thegreatest overall amount of ß-ionone to emission fromthe whole flower. There were three different patterns in emissionof volatiles from plants in response to different light conditions:(1) emission patterns identical irrespective of light environment,with maximum emission in the ‘endogenous’ dark period,i.e. when the plant would normally have been in the dark (-pinene);(2) similar emission in all treatments, with an increase anddecline over a period of 26 h (5-acetoxy linalool, cyclic ß-ionone,dodecyl acetate and (Z)-n-heptadec-8-ene); and (3) emissionin all treatments but enhanced in the dark, with a 27.5 h periodin some cases (cyclic ß-ionone endoperoxide, dihydroß-ionone, ß-ionone, and ‘total volatiles’).Preliminary evidence is presented for endogenous control ofemission of a number of volatiles such as -pinene, with perhapsdiurnal control of others such as ß-ionone. Copyright2000 Annals of Botany Company Boronia megastigma, brown boronia, SPME, headspace, floral volatiles, ß-ionone