用膨化柱填料的方法从红藻中规模分离纯化R-藻红蛋白(英)

以Phenyl_sepharose作为柱填料 ,用streamline柱层析技术从红藻 (Palmariapalmata (Lannaeus)Kuntze)中规模分离捕光色素蛋白———R_藻红蛋白。由于不是传统的从层析柱上方进样 ,而是用泵将样品从streamline层析柱的下方加样 (从下至上 ) ,因而解决了用一般层析柱分离R_藻红蛋白时海藻抽提液中大量的粘性多糖堵塞层析柱的难题。用P .palmata粗提液上样后 ,分别用 0 .2mol/L、0 .1mol/L和 0 .0 5mol/L的 (NH4) 2 SO4溶液从相反的方向 (即从上到下 )洗脱层析柱 ,发现这些洗脱液中的藻红蛋白纯度已经较高。然后将洗脱液透析去盐 ,用阴离子交换柱层析 (Q_sepharose)进一步纯化。经过这两次柱层析后 ,R_藻红蛋白的纯度 (OD565/OD2 80 )超过 3.5 ,高于一般认可的R_藻红蛋白的纯度标准 3.2 ;产率为每克冷冻P .palmata可纯化 0 .12 2mg高纯度的R_藻红蛋白 ,比使用一般分离方法的产率要高 10倍。这些结果表明 ,使用本文报道的方法纯化藻红蛋白 ,将会使作为生化检测试剂的藻红蛋白市场价格大幅度下降。     

STRUCTURE AND DYNAMICS OF A POPULATION OF PALMARIA PALMATA (RHODOPHYTA) IN NORTHERN SPAIN1

Palmaria palmata (Linnaeus) O. Kuntze (Rhodophyta, Palmariaceae) is a seaweed commercially harvested for human consumption. Its population density, size structure, and frond dynamics were investigated from May 1999 to May 2001 at one intertidal locality in the northern coast of Spain, which is within the southern distributional boundary of the species in the eastern Atlantic coasts. The effect of size, age, and the life‐history phase (haploid vs. diploid) on frond growth and mortality were also evaluated. The study was carried out by mapping and monitoring fronds in the field. New fronds (macroscopic recruits or sprouts) appeared in spring, but subsequent mortality of these young fronds and detachment of the host plant led to lower density values in January. Palmaria palmata exhibited a distinctive seasonal growth cycle, with positive net growth from March to August and breakage from August to March. Interannual differences were also detected, with higher net growth in 2000 than in 1999. Net growth was apparently independent of age, reproductive status (fertile vs. reproductive), and life‐history phase (haploid vs. diploid) but was dependent on size, as longer fronds showed minor growth or greater breakage than small ones. Mortality, on the other hand, was more dependent on age than on size in the period analyzed (March–May 2000). Results of the study indicate that both size and age should be included as state variables and temporal changes in transition probabilities considered in the development of demographic models of the species.     

ACCLIMATION OF THE PHOTOSYNTHETIC APPARATUS OF PALMARIA PALMATA (RHODOPHYTA) TO LIGHT QUALITIES THAT PREFERENTIALLY EXCITE PHOTOSYSTEM I OR PHOTOSYSTEM II1

Acclimation of the photosynthetic apparatus to light absorbed primarily by phycobilisomes (which transfer energy predominantly to photosystem II) or absorbed by chlorophyll a (mainly present in the antenna of photosystem I) was studied in the macroalga Palmaria palmata L. In addition, the influence of blue and yellow light, exciting chlorophyll a and phycobilisomes, respectively, ivas investigated. All results were compared to a white light control. Complementary chromatic adaptation in terms of an enhanced ratio of phycoerythrin to phycocyanin under green light conditions was observed. Red light (mainly absorbed by chlorophyll a) and green light (mainly absorbed by phycobilisomes) caused an increase of the antenna system, which was not preferentially excited. Yellow and blue light led to intermediate states comparable to each other and white light. Growth was reduced under all light qualities in comparison to white light, especially under conditions preferably exciting phycobilisomes (green light-adapted algae had a 58% lower growth rate compared to white light-adapted algae). Red and blue light-adapted algae showed maximal photosynthetic capacity with white light excitation and significantly lower values with green light excitation. In contrast, green and yellow light-adapted algae exhibited comparable photosynthetic capacities at all excitation wavelengths. Low-temperature fluorescence emission analysis showed an increase of photosystem II emission in red light-adapted algae and a decrease in green light-adapted algae. A small increase of photosystem I emission teas also found in green light-adapted algae, but this was much less than the photosystem II emission increase observed in red light-adapted algae (both compared to phycobilisome emission). Efficiency of energy transfer from phycobilisomes to photosystem II was higher in red than in green light-adapted algae. The opposite was found for the energy transfer efficiency from phycobilisomes to photosystem I. Zeaxanthin content increased in green and blue light-adapted algae compared to red, white, and yellow light-adapted algae. Results are discussed in comparison to published data on unicellular red algae and cyanobacteria.     

Effects of temperature on the photoreactivation of ultraviolet-b–induced dna damage in Palmaria palmata (Rhodophyta)

The accumulation of DNA damage (thymine dimers and 6-4 photoproducts) induced by ultraviolet-B radiation was studied in Palmaria palmata (L.) O. Kuntze under different light and temperature conditions, using specific monoclonal antibodies and subsequent chemiluminescent detection. Both types of damage were repaired much faster under ultraviolet-A radiation (UVAR) plus photosynthetically active radiation (PAR) than in darkness, which indicates photoreactivating activity. At 12° C, all thymine dimers were repaired after 2 h irradiation with UVAR plus PAR, whereas 6-4 photoproducts were almost completely repaired after 4 h. After 19 h of darkness, almost complete repair of 6-4 photoproducts was found, and 67% of the thymine dimers were repaired. In a second set of experiments, repair of DNA damage under UVAR plus PAR was compared at three different temperatures (0, 12, and 25° C). Again, thymine dimers were repaired faster than 6-4 photoproducts at all three temperatures. At 0° C, significant repair of thymine dimers was found but not of 6-4 photoproducts. Significant repair of both thymine dimers and 6-4 photoproducts occurred at 12 and 25° C. Optimal repair efficiency was found at 25° C for thymine dimers but at 12° C for 6-4 photoproducts, which suggests that the two photorepair processes have different temperature characteristics.     

ACCLIMATION OF PALMARIA PALMATA (RHODOPHYTA) TO LIGHT INTENSITY: COMPARISON BETWEEN ARTIFICIAL AND NATURAL LIGHT FIELDS

The acclimation of the photosynthetic apparatus of Palmaria palmata (L.) to light intensity was examined in the field and under laboratory conditions. Algae from 3 different shore levels and from laboratory cultures adapted to 6 different photon flux densities were compared. This was done on the basis of light doses, which were delivered by different light regimes in the field and in the laboratory. Laboratory samples were adjusted to constant photon flux densities between 7 and 569 μmol photons·m ^{? 2}·s ^{? 1} in a 16:8 light:dark photoperiod. Under field conditions the daily amplitudes reached up to approximately 2000 μmol photons·m ^{? 2}·s ^{? 1} within a natural daily light course. Over the course of 14 days the light doses resulting from those different regimes are similar for both treatments. An increasing growth rate per day with increasing light doses was observed in the laboratory. Growth was saturated at 113 mol photons·m ^{? 2}·14 d ^{? 1}. Light saturation points (E_k) of photosynthesis increased with increasing light doses for both field and laboratory samples, and all E_k values were significantly related to the growth light dose. A correlation between fresh weight‐related lutein content and growth light dose was found for laboratory samples only, whereas the lutein:chlorophyll a (chl a) ratio was strongly correlated with E_k for laboratory and field samples. The content of chl a and phycoerythrin (PE) per fresh weight decreased significantly with increasing light doses under field conditions. Simultaneously, the PE:chl a ratio increased, whereas this ratio was not influenced by laboratory treatments. The correspondence of E_k values for field and laboratory treatments indicated that they were affected mainly by light dose. However, the variability in pigmentation was mainly dependent on temporal variability in light intensity (the amplitude of variations in incident light).     

Some characteristics of photosynthetic inorganic carbon uptake of a marine macrophytic red alga

Abstract Some characteristics of photosynthetic inorganic carbon uptake by Palmaria palmata, a marine red macroalga, have been measured under physiological conditions in artificial seawater. The apparent affinity of thallus for CO₂ [K_1/2(CO₂)] at pH 8.0 and 15°C was 21.4±3.0mmol m^?3 CO₂ under air, and 25.7±70mmol m^?3 CO₂ under N₂. The corresponding values of V_max were 2.98 ± 0.42 and 3.65±0.87 mmol O₂ evolved g Chr^?1 s^?l. The apparent K_m(CO₂) of isolated ribulose bisphosphate carboxylase was determined at pH 8.0 and 30 °C to be 30.2 mmol m^?3 CO₂, and the corresponding value of V_max was 19.67 μniol CO₂ g protein^?1 s^?1. The CO₂ compensation points of the thallus were measured in artificial seawater at pH 8.0 under air and N₂, using a gas-chromatographic method. The values were relatively low, rising from 10 cm³ m^?3 at 15°C, to 35 cm³ m^?3 at 25°C, but were not affected by the O₂ concentration. The lack of an effect of O₂ on photosynthesis and on compensation point indicates that there is little photorespiratory CO₂ loss in this macroalga. The high affinity of the thallus for CO₂, and the low CO₂ compensation concentrations, are consistent with the occurrence of bicarbonate uptake in this alga.     

Effects of resource heterogeneity on nitrogen translocation within clonal fragments of Sasa palmata: an isotopic (15N) assessment

BACKGROUND AND AIMS: Clonal fragments of the rhizomatous dwarf bamboo Sasa palmata, which widely predominates in temperate regions of Japan, were grown under heterogeneous resource conditions such as gap understories or nutrient-patchy grassland. Clonal fragments develop multiple ramets with long rhizomes and appear to be physiologically integrated by the translocation of assimilates. The glasshouse experiment reported here was designed to clarify the mechanisms of physiological integration of nitrogen more precisely. METHODS: To assess how resource conditions influence the amount of nitrogen translocation, and which organ acts as the strongest sink, two experiments were conducted that traced movement of 15N label between interconnected pairs of ramets to compare homogeneous and heterogeneous light and soil nitrogen conditions. KEY RESULTS: The amount of 15N translocated to leaves was between 9% and 11% greater in high-N and high-light ramets in the heterogeneous compared with homogeneous treatments. Under heterogeneous soil nitrogen conditions, translocation increased from individual ramets in resource-rich patches to ramets in resource-poor patches, while the reverse was true under heterogeneous light environments, reflecting differences in the positions of leaves that act as the strongest sinks. Neither the mass increments nor the total mass of clonal fragments was significantly affected by heterogeneity of either light or nutrients, possibly because the experimental period was too short for differences to manifest themselves. CONCLUSIONS: This study clearly demonstrated that nitrogen is readily translocated between ramets, particularly under heterogeneous resource conditions. The translocation patterns were governed by functional 'division of labour' mechanisms that resulted in net nitrogen movement from understory sites to gaps, thereby enhancing the carbon acquisition of the whole fragment. Thus, physiological integration may provide benefits for S. palmata when it is growing under heterogeneous conditions in which there are deficits of certain environmental resources.     

Investigating dietary preferences in two competing dipterans, Coelopa frigida and Coelopa pilipes, using stable isotope ratios of carbon and nitrogen

Two species of seaweed fly, Coelopa frigida (Fabricius) and Coelopa pilipes (Halliday) (both Diptera: Coelopidae: Coelopini), compete for resources within deposits of marine algae washed ashore on British beaches. Previous studies report that adult flies exhibit algal‐specific behaviour that may influence interspecific interactions. It is predicted that coelopid larvae may also demonstrate algal‐specific dietary preferences. Larval dietary preferences are investigated by comparing the ratios of ¹³C/¹²C and ¹⁵N/¹⁴N in both wild flies and macroalgae to those of laboratory‐reared flies. Results showed only a small difference between the stable isotope ratios of the most abundant algae, Laminaria spp. (Laminariaceae) and Fucus spp. (Fucaceae), although there were significant differences between wild adult coelopids. This result illustrates different metabolic processes in two closely related species. The stable isotope ratios of wild‐caught coelopids were found to differ significantly from laboratory‐reared coelopids. This is either the result of red algae in the diet of natural populations or a difference in bacterial communities. We suggest that experiments with laboratory‐reared flies/specimens can greatly increase the utility of stable isotope analysis in the investigation of animal food webs, even where potential diets are isotopically similar. However, this approach is dependent on re‐creations that accurately mimic natural conditions.