The Mass Culture of Porphyridium cruentum

A study was made of the effect of temperature, detention period, light intensity, and salinity on the growth rate and over-all light energy conversion efficiency of Porphyridium cruentum cultured on a medium consisting of concentrated sea water and sewage enriched with urea, chelated iron, and other additives. It was found that the optimal temperature was within the range of 21 to 26 C. Growth was retarded at temperatures less than 13 C, and completely inhibited above 31 C. Over-all light energy conversion efficiency increased from 2.24% at the 4-day detention period to 2.76% at the 10-day period. Conversion efficiency ranged from 5.8% at a light energy absorption rate of 8.2 cal:liter:min to 2.3% at 35 to 39 cal:liter:min.

At salt concentrations less than 3.5%, Porphyridium could not successfully compete with other algae in open cultures. Salt concentrations as high as 4.6% had no inhibitory effect on its growth.

In studies on nutrition, it was found that growth on a medium of salts used in formulating synthetic sea water dissolved in sewage was equal to that on a control medium consisting of concentrated sea water and sewage (see above). They showed that sewage contains a substance or substances essential for optimal growth. Vitamin B₁₂ alone could not substitute for it.

     

Pigments et salinité chez Porphyridium

Pigments and salinity in Porphyridium.—An opal glass light transmission method is used for estimating the proportions of pigments in Porphyridium sp. Lewin, grown in artificial media. The cells show an Increase in chlorophyll/B–phycoerythrin ratio in media twice or thrice as saline as sea water, Chlrophyll/carotenoïds ratio is low in media the salinity of which is either low or high. In the case of phycoerythrins, light–absorption ratio at 500 nm and 545 nm vary also with the salinity. Une méthode de mesure par transmission de lumière á travers des lames opalines est utilisée pour évaluer les proportions de pigments chez Porphyridium sp. Lewin cultivé milieux artificiels. Les cellules montrent une augmentation du rapport chlorophylle/B.-phycoérythrine dans les milieux deux outrois fois plus salés que l'eau de mer. Le rapport chlorophylle/carotenoïdesest faible dans les milieux dont la salinityé est soit faible soit élevée. Dans le cas des phycoérythrines, le rapport des absorptions de lumière à 500 nm et 545 nm varie aussi avec la salinityé.     

Observations on Cellular Structures of Porphyridium cruentum

The cellular structure of Porphyridium cruentum was studied with both light and electron microscope. The photosynthetic plastid in this red alga was found to be structurally similar to that in the Chlorophyceae and higher green plants. The phycobilins, as well as the chlorophyll, seem to be associated with the lamellae of the plastid. The pyrenoid, a region of low lamellar density, contains no tubules, and does not appear to function in synthesis or storage of reserve material. Grains of floridean starch are located in the cytoplasm, outside the plastid. Typical mitochondrial organelles were not observed. The nucleus is eccentric, and contains a nucleolus located on the inner face of the nucleus, nearest the plastid. The schedule for staining the nucleus is given in detail. Other cell structures (sheath, dictyosomes, etc.) are described. Growing cells in light of intensity leads to disruption of the parallel arrangement of the lamellar characteristic of cells grown in moderate light.     

Observations on cellular structures of Porphyridium cruentum

The cellular structure of Porphyridium cruentum was studied with both light and electron microscope. The photosynthetic plastid in this red alga was found to be structurally similar to that in the Chlorophyceae and higher green plants. The phycobilins, as well as the chlorophyll, seem to be associated with the lamellae of the plastid. The pyrenoid, a region of low lamellar density, contains no tubules, and does not appear to function in synthesis or storage of reserve material. Grains of floridean starch are located in the cytoplasm, outside the plastid. Typical mitochondrial organelles were not observed. The nucleus is eccentric, and contains a nucleolus located on the inner face of the nucleus, nearest the plastid. The schedule for staining the nucleus is given in detail. Other cell structures (sheath, dictyosomes, etc.) are described. Growing cells in light of intensity leads to disruption of the parallel arrangement of the lamellar characteristic of cells grown in moderate light.     

Method for B-phycoerythrin purification from Porphyridium cruentum

Summary Porphyridium cruentum extract was treated with rivanol for the precipitation and elimination of the polysaccharide typical for this alga, while all phycobiliproteins remained solubilized. After their precipitation with ammonium sulphate, B-phycoerythrin was differentially separated from the other phycobiliproteins, and rivanol was removed by Sephadex G-25 gel filtration. The purity of B-phycoerythrin was proved.Abbreviations B-PE B-phycoerythrin - b-PE b-phycoerythrin - R-PC R-phycocyanin - APC allophycocyanin - PBP phycobiliproteins     

Porphyridium violaceum,eine marine neue Art

Zusammenfassung 1. Die neubeschriebene marinePorphyridium-Art unterscheidet sich von dem terrestrisch lebenden, aber auch im Meerwasser gefundenenPorphyridium purpureum durch ihre größeren, violett gefärbten Zellen.2. Teilung und Wachstum der Zellen vonPorphyridium violaceum passen sich dem Belichtungsrhythmus an. Die während der 10stündigen Dunkelheit geteilten Zellen sind 9 bis 11µ dick, sie vergrößern sich während der Lichtperiode auf 11 bis 14µ.

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Porphyridium violaceum, a marine new species

The new species is marine, whereasPorphyridium purpureum (= P. cruentum), first known only from terrestrial habitats, is halophilic and has been found several times in seawater.Porphyridium violaceum differs from the above mentioned species by a larger diameter and the colour of its cells.

     

Phycobilisome Structure of Porphyridium cruentum: POLYPEPTIDE COMPOSITION

Purified phycobilisomes of Porphyridium cruentum were solubilized in sodium dodecyl sulfate and resolved by sodium dodecyl sulfate-acrylamide gel electrophoresis into nine colored and nine colorless polypeptides. The colored polypeptides accounted for about 84% of the total stainable protein, and the colorless polypeptides accounted for the remaining 16%. Five of the colored polypeptides ranging in molecular weight from 13,300 to 19,500 were identified as the α and β subunits of allophycocyanin, R-phycocyanin, and phycoerythrin. Three others (29,000-30,500) were orange and are probably related to the γ subunit of phycoerythrin. Another colored polypeptide had a molecular weight of 95,000 and the characteristics of long wavelength-emitting allophycocyanin. Sequential dissociation of phycobilisomes, and analysis of the polypeptides in each fraction, revealed the association of a 32,500 molecular weight colorless polypeptide with a phycoerythrin fraction. The remaining eight colorless polypeptides were in the core fraction of the phycobilisome, which also was enriched in allophycocyanin. In addition, the core fraction was enriched in a colored 95,000 dalton polypeptide. Inasmuch as a polypeptide with the same molecular weight is found in thylakoid membranes (free of phycobilisomes), it is suggested that this polypeptide is involved in anchoring phycobilisomes to thylakoid membranes.     

Evaluation of the protein quality of Porphyridium cruentum

The amino acid profile of the red microalga Porphyridium cruentum and its protein extract have been determined in order to assess the nutritional quality of this biomass for human consumption. Total protein determined by elemental analysis represented 56 % of its dry weight. Hydro-soluble proteins extracted at pH 12 and 40 °C were analysed by the Lowry method giving 47 %, which represented 84 % of total protein per dry weight. The amino acid sequence of the biomass and the protein extract was composed of a set of essential (39 % for the former and 37 % for the latter) and non-essential amino acids (61 % for the former and 63 % for the latter) that compares favourably with the standard protein/amino acid requirements proposed by Food and Agricultural Organisation and World Health Organisation.     

铜绿紫球藻(Porphyridium aerugineum)755培养的研究

紫球藻是一种具有潜在应用价值的经济微藻,它的生长速率受各种环境因子的影响.本文研究了不同光强、光周期、盐度、NaHCO3浓度、葡萄糖浓度、培养方式等因子对铜绿紫球藻(Porphyridium aerugineum)755生长的影响,并确定其最佳的培养条件.此外还分析了该藻的吸收光谱,为其培养提供参考数据.     

超声波降解紫球藻胞外多糖研究

通过测定溶液粘度,判断超声波降解紫球藻(Porphyridium cruentumi)胞外多糖的效果。运用均匀设计对超声波降解紫球藻胞外多糖的影响因素(处理振幅、时间、脉冲)进行优化,获得超声波处理的最佳条件:振幅39%、处理时间245s和脉冲9.5s。在最佳条件下,胞外多糖的粘度为2.98mm²/s,与预测值一致。采用DPS软件对实验结果进行二次多项式分析与拟合,并对模型和回归系数进行显著性检验,建立了以胞外多糖粘度为目标的回归方程式。     

紫外线对紫球藻的生物学效应

采用紫外线辐照紫球藻,处理剂量分别为10s、20s、30s、60s、90s、120s和180s。结果表明,10s剂量对紫球藻有促长作用,20s及30s对藻细胞生长和各项生理生化指标影响不显著,30s以上处理对其生长以及代谢产物的合成与分泌有抑制作用,且照射时间越长,抑制越强烈,紫球藻对紫外线的耐受极限为120s。结果还表明,高剂量(20~90s)照射能增加单细胞代谢产物含量;经紫外线辐照后的藻细胞第二代培养物在生长速度、叶绿素a含量、胞外多糖和β-胡萝卜素产量等与对照组相似。     

Noncovalent Intermolecular Forces in Phycobilisomes of Porphyridium cruentum

Using sensitized fluorescence as a measure of intactness of phycobilisomes isolated from Porphyridium cruentum, the effects of various environmental perturbations on phycobilisome integrity were investigated. The rate of phycobilisome dissociation in 0.75 ionic strength sodium salts proceeds in the order: SCN⁻ > NO₃⁻ > Cl⁻ > C₆H₅O₇³⁻ > SO₄²⁻ > PO₄³⁻, as predicted from the lyotropic series of anions and their effects on hydrophobic interactions in proteins. Similarly, increasing temperature (to 30 C) and pH values approaching the isoelectric points of the biliproteins stabilize phycobilisomes. Deuterium substitution at exchangeable sites on the phycobiliproteins decreases the rate of phycobilisome dissociation, while substitution at nonexchangeable sites increases rates of dissociation. It is concluded that hydrophobic intermolecular interactions are the most important forces in maintaining the phycobilisome structure. Dispersion forces also seem to contribute to phycobilisome stabilization. The adverse effects of electrostatic repulsion must not be ignored; however, it seems that the requirement of phycobilisomes of high salt concentrations is not simply countershielding of charges on the proteins.     

紫球藻多糖化学结构解析

为明确紫球藻多糖的化学结构,本文采用化学分析和光谱分析方法对紫球藻多糖的一级糖链结构进行了分析。GC分析表明该多糖由木糖、葡萄糖和半乳糖组成,为一种杂多糖,其摩尔比为:2.96∶1.25∶3.06;红外光谱分析结果显示紫球藻多糖为硫酸化多糖,糖苷键类型为β构型;化学分析结果推断紫球藻多糖糖链连接方式以1→3为主,存在少量1→2,1→4,1→6键型,且半乳糖在支链或主链末端有较大量的存在,木糖和葡萄糖在主链或靠近主链区域有特定分布;NMR分析显示紫球藻多糖的硫酸酯基连在C-6上,且多糖的糖苷键为β型;GC-MS联机分析进一步确定紫球藻多糖为一种主要含有1→3糖苷键,并含有1→4,1→6糖苷键的杂多糖。综合上述分析,推断出紫球藻多糖的糖链主链的重复单元结构。     

Porphyridium aerugineum,n. sp.

Ohne Zusammenfassung     

Properties and Ultrastructure of Phycoerythrin From Porphyridium cruentum

Phycoerythrin, a photosynthetic accessory pigment, was isolated from Porphyridium cruentum and examined by electron microscopy and disc gel electrophoresis. The absorption monomer, with maxima at 563, 545, and a shoulder at 500 nm, has a molecular weight of about 300,000. With phosphotungstic acid staining it appears as a tightly structured disc-shaped particle possessing a mean diameter of 101 ± 0.4Ä and height of 54 ± 0.7Å. The absorption maxima remained the same in glutaraldehyde fixed material, and in dimer and trimer aggregates. Treatment with sodium dodecyl sulfate caused a breakdown into smaller units accompanied by a loss of the 563 nm peak. It is suggested that this absorption monomer is the in vivo functional species and comparable to the phycocyanin hexamer, but structurally distinguishable at the ultrastructural level. It has been calculated that about 35 phycobiliprotein molecules can be contained within each phycobilisome. There are 1.4 × 10³ chlorophyll molecules per phycobilisome, but not contained within it.     

A closed system for outdoor cultivation of Porphyridium

Experience accumulated during the past few years indicates that the main problems in the large-scale cultivation of algae in open ponds are low productivity and contamination. Thus, the use of closed systems can be an alternative method of cultivation. In the present study, a closed system made of polyethylene sleeves was compared with open ponds with respect to growth and polysaccharide production of two species of Porphyridium: Porphyridium sp. and P. aerugineum. For both species, cell number, biomass, and polysaccharide production were higher in the sleeves than in the ponds. It seems that polyethylene sleeves have the following advantages over open ponds: high light availability, high rate of heating and cooling, improved turbulence, relative lack of contamination, and prevention of evaporation and hence of fluctuation in salinity.     

Phycobilisomes of Porphyridium cruentum. I. Isolation

A procedure was developed for the isolation of phycobilisomes from Porphyridium cruentum. The cell homogenate, suspended in phosphate buffer (pH 6.8), was treated with 1% Triton X-100, and its supernatant fraction was centrifuged on a sucrose step gradient. Phycobilisomes were recovered in the 1 M sucrose band. The phycobilisome fraction was identified by the characteristic appearance of the phycobilisomes, and the absorbance of the component pigments: phycoerythrin, R-phycocyanin, and allophycocyanin Isolated phycobilisomes had a prolate shape, with one particle axis longer than the other. Their size varied somewhat with their integrity, but was about 400–500 A (long axis) by 300–320 A (short axis). Phycobilisome recovery was determined at six phosphate buffer concentrations from 0.067 M to 1.0 M. In 0.5 M phosphate, phycobilisome yield (60%) and preservation were optimal. Such a preparation had a phycoerythrin 545 nm/phycocyanin 620 nm ratio of 8.4. Of the detergents tested (Triton X-100, Tween 80, and sodium deoxycholate), Triton X-100 gave the best results Freezing of the cells caused destruction of phycobilisomes.