Intracellular phosphorus pool in a culture of the cyanobacterium Spirulina platensis

An intracellular phosphorus pool in a monoculture of the cyanobacterium Spirulina platensis was assessed using radioactive and nonradioactive phosphorus. The derived dependence of specific growth rate on the intracellular content of mineral phosphorus can be presented in the form of the Droop equation. It was found that the stage of replenishment of the intracellular phosphorus pool may affect the phosphorus turnover estimation in aquatic environments from the results of short-term measurements of phosphorus uptake.     

Spectroscopic study of phycocyanobilin from the cyanobacteriumSpirulina platensis

Spectroscopic characterization of phycobiliprotein (PBP) isolated fromSpirulina platensis indicated that it had a molecular formula of C₃₃H₄₀N₄O₆ with molecular ion peak at m/e 586. The PBP was rich in aliphatic and acidic amino acid residues. The specific ultra-violet absorbance, infrared transmittance, specific absorbance coefficient, nuclear magnetic resonance and mass spectral analysis revealed thatS. platensis PBP was composed mainly of C-phycocyanin and allophycocyanin.     

Action of selected heavy metal ions on the photosystem 2 activity of the cyanobacteriumSpirulina platensis

Addition of different concentrations of heavy metal ions (Hg²⁺, Cu²⁺, Ni²⁺ and Pb²⁺) inhibited the photosystem 2 catalyzed electron transport activity (H₂O→p-benzo-quinone) of the cyanobacteriumSpirulina platensis. Hg²⁺ caused the inhibition in electron transport activity in very low concentrations compared to the other metal ions. Hg²⁺ at this low concentration specifically altered the spectral properties of phycocyanin of the phycobilisomes in the intact cells ofSpirulina, whereas other heavy metal ions were ineffective in this sense.     

Photosynthetic production of the filamentous cyanobacteriumSpirulina platensis in a cone-shaped helical tubular photobioreactor

The photosynthetic productivity of the filamentous cyanobacteriumSpirulina platensis was investigated in a cone-shaped helical tubular photobioreactor. A laboratory-scale photobioreactor was constructed with a 0.255-m² basal area and a conical shape (0.64 m high × 0.57 m top diameter). The photostage comprised transparent reinforced polyvinyl chloride (PVC) tubing with spirally wound, metal-wire reinforcing in the tubing wall (31 m in length and 1.6 cm internal diameter with 0.25 cm wall thickness; total volume = 6.23 l). The inner surface of the photostage (0.651 m²) was illuminated with compact fluorescent cool white lamps; the photosynthetically active radiation (400–700 nm) energy input into the photobioreactor was 1249 KJ day^–1 (12 h day/12 h night). The operation of an air-lift photobioreactor with CO₂-enriched air (4%) at a flow rate of 0.3 l min^–1 showed a maximum daily photosynthetic efficiency of 6.83% under batch-culture conditions. This corresponded to a production rate of 15.9 g dry biomass m^–2(basal area) day^–1 or 0.51 g dry biomass l medium^–1 day^–1.     

Role of light and photosynthesis on the acclimation process of the cyanobacteriumSpirulina platensis to salinity stress

The response ofSpirulina platensis cells to salinity stress was studied. Once adapted to the higher osmoticum, photosynthetic parameters such as the maximum rate of photosynthesis under saturating irradiance (P_max) and the initial slope of the P-I curve () are reduced by 15% and 25% in 0.5 M NaCl grown cells, respectively. Salt-adapted cells have a modified biochemical composition; reduced protein and chlorophyll content, and an increased level of carbohydrates. The reduction in the photosynthetic capacity of the salt-adaptedSpirulina cells reflects a lower ability to utilize light energy and results in an increase in the susceptibility of the stressed cells to photoinhibition. This conclusion is supported by the finding that cultures exposed to salt stress show not only a decrease in growth rate (), but lose the ability to respond to increased irradiance with an increase in growth. The use of variable fluorescence as a fast and reliable measurement to follow the changes in PSII of salt-stressesSpirulina cells enables following the early events of salinity shock. It indicates that as soon as the cells are exposed to salt, a protection mechanism is induced. This mechanism does not require any protein synthesis and may take place even in the dark, though at somewhat reduced effectiveness. The significance of the result in providing a better understanding of the interaction between two environmental stresses — light and salinity — and their application in the outdoor mass cultivation ofSpirulina are discussed.Author for correspondence     

Recovery of c-phycocyanin from the cyanobacteriumSpirulina maxima

Spirulina biomass was separated into two fractions which may have various uses. A phycocyanin fraction may provide a food colourant and biomarkers, and a protein-rich leftover may be useful as aquaculture feed. Activated charcoal adsorption, ultrafiltration and spray drying were used effectively to produce a high quality colourant grade phycocyanin, while activated charcoal adsorption, ammonium sulphate precipitation, dialysis and chromatography were effective in preparing reagent grade phycocyanin.     

我国北方3种典型土壤-作物体系中微生物量磷库特征

土壤微生物量磷(Microbial Biomass Phosphorus, MBP)是土壤磷组分中最为活跃的形态,在土壤磷素的形态转化与生物地球化学循环过程中起着关键作用,是植物可利用磷的重要来源。研究土壤MBP库容的大小对于充分认识微生物的固磷潜力和掌握土壤磷素循环与转化能力意义重大。以我国北方农田3种典型的土壤-作物体系为研究对象,基于定点采样,通过分析测定采集的362个表层(0—30 cm)土壤样品来量化不同土壤-作物体系MBP库容的大小。结果表明：黑土-春玉米、潮土-冬小麦/夏玉米、灰漠土-棉花体系表层土壤MBP平均含量分别为17.36、14.45、8.75 mg/kg,且不同土壤-作物体系间MBP含量存在显著差异;3种土壤-作物体系表层土壤(0—30 cm)MBP库容的大小分别为83.60、54.26、39.80 kg P/hm~2,其储存的磷在数量上相当于当季作物需磷量的1.10—2.73倍,表明土壤MBP库是农田生态系统中一个不容忽视的巨大有效养分磷储库。其库容的大小受土壤性质和气候因素的共同影响,土壤pH、有机碳、年均气温和年均降雨量是我国北方农田土壤MBP库容大小的主...     

An Increase in the Intracellular Concentration of cAMP Triggers Formation of an Algal Mat by the Cyanobacterium Spirulina platensis

The intracellular concentration of cAMP increased rapidly when3-isobutyl-l-methylxanthine (IBMX), an inhibitor of cAMP phosphodiesterase,was added to a suspension of Spirulina platensis cells. Additionof IBMX also enhanced respiratory activity and cell motilityand, as a consequence, a floating algal mat was induced. (Received July 31, 1992; Accepted November 9, 1992)     

Sediment phosphorus cycling in a nutrient-rich embayment in relation to sediment phosphorus pool and release

Limnology - A semi-enclosed river-mouth bay (Kojima Bay) and the artificial lake within it (Kojima Lake) were studied to examine their nutrient storage and export processes and characteristics. The...     

Effects of phosphorus concentration and light intensity on the biomass composition of Arthrospira (Spirulina) platensis

This paper presents the effects of various phosphorus concentrations (10, 50, 250 and 500 mg l(-1) K(2)HPO(4)) on the biomass production and composition of Arthrospira (Spirulina) platensis in relation to light intensity (24, 42 and 60 μE m(-2) s(-1)). The maximum biomass production was 3,592 ± 392 mg l(-1) and this was observed in 250 mg l(-1) K(2)HPO(4) at 60 μE m(-2) s(-1) light intensity after 32 days of cultivation. A maximum specific growth rate (μ(max)) of 0.55 d(-1) was obtained in 500 mg l(-1) K(2)HPO(4) at 60 μE m(-2) s(-1). The protein, lipid and chlorophyll contents of the biomass varied from 33.59 to 60.57 %, 5.34 to 13.33 % and 0.78 to 2.00 %, respectively. The most significant finding was that phosphorus limitation (10 mg l(-1) K(2)HPO(4)) caused a drastic increase of the carbohydrate content (59.64 %). The effect of phosphorus limitation on the carbohydrate content was independent of the light intensity. The accumulated carbohydrates are proposed to be used as substrate for biofuel generation via one of the appropriate biomass energy conversion technologies. Also, it was observed that phosphorus removal is a function of biomass density, phosphorus concentration and light intensity.     

钝顶螺旋藻SP1(Spirulina platensis)对集约化养殖尾水氮磷的去除效果

针对集约化养殖模式后期硝酸盐氮和磷酸盐浓度较高的问题,实验设置生物絮团养殖尾水(BFW)和BG11培养液(BGW)两种水体环境,并以池塘常见优势微藻——绿色颤藻OC1(Oscillatoria chlorina)作为对比,研究分析了钝顶螺旋藻SP1(Spirulina platensis)对集约化养殖尾水氮磷的去除效果...     

Intracellular phosphorus metabolism of Microcystis aeruginosa under various redox potential in darkness

Phosphorus metabolism of Microcystis aeruginosa was studied under gradient redox potential from 252 mV to –70 mV in darkness. The release of phosphorus occurred in all the treatments, and this process was accelerated in darkness when the redox potential was lowered. Low redox potential in darkness stimulated the accumulation of polyphosphate (PolyP) and the degradation of polyglucose. The synthesis of PolyP delayed the decrease of intracellular orthophosphate. The death of M. aeruginosa was slowered when the redox potential was low in darkness. The accumulation of PolyP under low redox potential in the dark was very important to M. aeruginosa for endurance through the unfavorable growth conditions for maintaining phosphorus concentration, energy storage, and other physiological functions. The ability to accumulate PolyP in the dark and negative redox potential may be of considerable advantage in the low-light, organically rich, and low-redox habitats.     

Intracellular distribution of calcium and phosphorus during the first cell division of the sea urchin egg

The intracellular distribution of calcium and phosphorus during metaphase and anaphase of the first cleavage in sea urchin eggs was studied with the electron-probe microanalyzer. This study allowed a comparison of the relative concentrations of both elements on the polar and cleavage furrow regions of the membrane and on the mitotic asters and cytoplasm. The results show that in most eggs, both calcium and phosphorus are more highly concentrated in the mitotic asters than in surrounding cytoplasm during both anaphase and metaphase. Calcium is more concentrated at the furrow region than at the polar region during metaphase but not anaphase. The role of calcium during mitosis was reviewed with special reference to the theories on the formation of the cleavage furrow along the equatorial zone between two mitotic centers.     

Aliidiomarina sanyensis sp. nov., a hexabromocyclododecane assimilating bacterium from the pool of Spirulina platensis cultivation, Sanya, China

A novel Gram-negative, rod shaped, motile, non-spore-forming, aerobic, brominated flame retardant hexabromocyclododecane-assimilating bacterium, designated strain GYP-17^T, was isolated from a pool of marine Spirulina platensis cultivation, Sanya, China. Colonies on 1/10 strength of marine Glycerol Enriched Medium plates were circular, dark-brown, 1–2 mm in diameter, and with regular margins. Growth occurred at 10–45 °C, 1–10 % (w/v) NaCl and pH of 7–9. The polar lipids were composed of phosphatidylethanolamine, three unidentified phospholipids and one unidentified polar lipid. The major fatty acids were iso-C_17:1ω9c/10-methyl-C_16:0 (summed feature 9, 20.75 %), iso-C_15:0 (17.70 %) and C_16:0 (6.40 %). The major respiratory quinone was Q-8. The DNA G + C content of the type strain was 53.6 mol%. Phylogenetic analysis revealed that strain GYP-17^T was a member of the genus Aliidiomarina and closely related to Aliidiomarina haloalkalitolerans with a 16S rDNA sequence similarity of 96.36 %. Results from the polyphasic taxonomy study support the conclusion that strain GYP-17^T represents a novel Aliidiomarina species, for which the name Aliidiomarina sanyensis sp. nov. is proposed. The type strain of A. sanyensis is GYP-17^T (=KCTC 32218^T =LMG 27471^T).     

Bacterioplanes sanyensis gen. nov., sp. nov., a PHB-accumulating bacterium isolated from a pool of Spirulina platensis cultivation

A Gram-negative, poly-3-hydroxybutyrate-accumulating rod bacterium, strain GYP-2^T, was isolated from a pool of marine Spirulina platensis cultivation, Sanya, China. Growth was observed at 10–45 °C and pH 6–10 in the presence of 1–10 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the new isolate belonged to Gammaproteobacteria and displayed 93.8–95.3 % 16S rRNA gene sequences similarities to members of the genera Thalassolituus, Oleibacter, and Oceanobacter, but house-keeping gene gyrB (encode DNA gyrase beta subunit) demonstrated that the new isolate was distantly related to Thalassolituus, Oleibacter, and Oceanobacter species (only 77–83 % gene gyrB sequences similarities).The G+C content of genomic DNA was 55 mol%. The major respiratory quinone was Q-9, while that for Oceanobacter kriegii LMG 6238^T was Q-8. Major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. On the basis of its physiological, chemotaxonomic, and molecular properties, strain GYP-2^T is suggested to represent a novel species of a new genus in Gammaproteobacteria, for which the name Bacterioplanes sanyensis gen. nov., sp. nov. is proposed. The type strain is GYP-2^T (=CGMCC 1.12392^T=KCTC 32220^T).     

Intracellular pool of free amino acids in a wild strain of Corynebacterium glutamicum and its lysine-producing mutants

The intracellular content of free amino acids was measured in the wild-type strain of Corynebacterium glutamicum 13032 and its lysine producing mutants 410 and 133, resistant to the combined effect of threonine and S-2-aminoethyl cysteine, a lysine analog. After 18- and 48-hour cultivation of all strains the major components of the amino acid pool were glutamic acid, alanine and lysine, and those of the cell-free supernatant were alanine and lysine. After 18-hour cultivation the lysine content in mutants was 2-3 times higher than in the wild-type strain. After 48-hour cultivation the lysine content in mutants remained unchanged and in the wild-type strain increased. After 18- and 48-hour cultivation the lysine content in the supernatant of mutants was 15 and 33 times higher than in that of the parental strain. These findings are compared with the activities of aspartokinase from Cor. glutamicum 13032, 410 and 133.     

Planktonic phosphorus pool sizes and cycling efficiency in coastal and interior British Columbia lakes

1. Limnologists have long acknowledged the importance of phosphorus (P) in determining the organism biomass and productivity of lake ecosystems. Despite a relatively large number of studies that have examined P cycling in lake ecosystems, there remain several substantial methodological issues that have impeded our understanding of P cycling in limnetic plankton communities. Two critical issues confronting ecologists are (1) a lack of precise measurements of the dissolved inorganic phosphorus (PO) and (2) accurate or complete measurements of dissolved P regeneration rates by plankton communities. 2. Here, we examine patterns of epilimnetic planktonic P pool sizes and turnover rates in eight lakes in British Columbia, Canada over a 2‐year period. We determine the concentrations and turnover times of P in various planktonic compartments (dissolved and various planktonic size fractions), using recently developed methods for estimating phosphate concentration and planktonic regeneration rates. 3. The pico‐ and nanoplankton size fraction (0.2–20 μm) played a central role in planktonic P cycling in lakes examined by this study. On average across lakes, pico‐ and nanoplankton contained >60% of the planktonic P, accounted for >90% PO uptake, and contributed 50% of the plankton community dissolved P regeneration rate. 4. PO concentrations determined by steady state bioassays (ssPO) were extremely low (87–611 pmol L⁻¹) and were 2–3 orders of magnitude less than simultaneously measured colorimetric soluble reactive phosphorus estimates. Lake ssPO concentrations increased linearly with total phosphorus (TP), and the slope of this relationship was approximately 1, indicating that PO remained a consistent proportion of the TP pool across a range of TP concentrations. 5. Turnover rates of the total planktonic P pool and the <20 μm pool became more rapid with increasing lake TP, indicating that, according to this metric, planktonic P cycling efficiency increased with TP concentrations. We also detected a significant relationship between particulate phosphorus (PP) <20 μm turnover time and seston N : P ratios, with PP <20 μm turnover times becoming slower with increasing seston N : P. These findings suggest that long‐standing conceptual models of nutrient cycling that predict slower cycling rates and decreasing cycling efficiency with increasing TP concentrations require further empirical examination. We postulate that patterns in lake P turnover and cycling efficiency are a result of complex interactions between plankton biomass and composition, and the ratios of multiple nutrients (C, N, P), rather than solely a function of the TP pool.