Alga Spirulina Research Articles

Spirulina protects against cadmium-induced hepatotoxicity in rats

Cadmium (Cd) is an environmental and industrial cumulative pollutant that most affects many organs specially the liver. The protective effect of Spirulina, filamentous blue green algae, on Cd – induced oxidative stress and hepatotoxicity was evaluated in male rats. Oral administration of water extract of Spirulina for seven days followed by an acute toxic dose of Cd (3.5 mg kg b.wt.-1), reduced the hepatotoxicity and attenuated the Cd-induced oxidative stress. Spirulina treatment showed marked reduction in serum aminotrasferase activities and elevation in lipid peroxidation and recovery of the endogenous levels of antioxidants following Cd-intoxication. The Cd-induced hepatic histopathological changes were also minimized with the tested extract. These results suggest that Spirulina algae might play a role in reducing the toxic effect of Cd and its antioxidant properties seems to mediate such a protective effect.

Synthesis of Chlorins Linked with Pyrazoline by 1,3-Dipolar Diazomethane Cycloaddition Reaction

Chlorins and bacteriochlorins, occurred in natural systems as a class of tetrapyrrolic macrocycles, have gained much interests in recent years because of their unique optical and photochemical properties. They can be utilized as the second generation photosensitizers for photodynamic therapy (PDT) of cancer and as models for photosynthetic reaction centers. Among the chlorophyll derivatives, pheophorbide, pyropheophorbide, purpurin and N-alkylimide of purpurin18 have been reported as potent photosensitizers with significant anticancer activity. Their derivatives were usually prepared by chemical modification of peripheral functional groups, particularly the vinyl group at 3-position. Our interest in the synthesis of chlorins as potential photosensitizers for PDT led us to explore new strategies for vinyl functionalization of pheophorbide-a by 1,3-dipolar cycloaddition methodology with diazomethane. 1,3-Dipolar [3+2] cycloaddition is an effective method for the synthesis of five-membered heterocycles. It is well known that diazomethane is a reactive reagent for 1,3dipolar cycloaddition with olefin to furnish pyrazoline derivatives, which serve as useful building blocks in the synthesis of various compounds through chemical transformation and/or ring cleavage. In the present work, the novel pyrazolinyl chlorins, promising versatile starting materials for further application by chemical transformation of pyrazoline ring for constructing new structure of chlorin, were synthesized by 1,3-dipolar cycloaddition reaction with chlorin and diazomethane. It was found that the vinyl group of pheophorbide-a 1, extracted from the alga Spirulina maxima, reacts slowly over a period of 3 days with ethereal

The Biological Effects of Depolymerized Sodium Spirulan and Sulfated Colominic Acid on Vascular Cells are Beneficial in Preventing Atherosclerosis

Atherosclerosis is a vascular lesion that is a common health problem in advanced countries. Functional damage of the vascular endothelial cells, vascular smooth muscle cell hyperplasia, and procoagulant/antifibrinolytic state of blood are generally observed in the lesion. Since polysaccharides such as heparin modulate vascular cell behavior through interaction with cytokines/growth factors, we hypothesized that polysaccharides from natural sources may possess beneficial biological activities that prevent atherosclerosis. Changes in cultured aortic endothelial and smooth muscle cells were investigated after treatment with the polysaccharides sodium spirulan (Na-SP) — a sulfated polysaccharide obtained from a hot water extract of the blue-green alga Spirulina platensis — and colominic acid (CA)prepared as a homopolymer of N-acetylneuraminic acid produced by Escherichia coli K1. The experiments suggest that depolymerized Na-SP and sulfated CA can function as precursors of the agents that prevent atherosclerosis. In particular, both the chemically modified polysaccharides significantly inhibit the proliferation of the arterial smooth muscle cells without exhibiting any toxic effects on the integrity of the vascular endothelial cell layers. The results also indicate that chemical modifications, for example, depolymerization of Na-SP and sulfation of CA, can control the biological effects of these polysaccharides on vascular cells.

Effects of Spirulina, a Blue-Green Alga, on Bone Metabolism in Ovariectomized Rats and Hindlimb-Unloaded Mice

The safety and effectiveness were examined of the spirulina alga on bone metabolism in ovariectomized estrogen-deficient rats and hindlimb-unloaded mice. The dosage range was from an amount equal to that recommended in so-called health foods for humans (0.08 g/kg BW/day) to a 100-fold higher dose. The bone mineral density (BMD) of the whole femur and tibia of ovariectomized rats in the any spirulina-treated groups was not significantly different from that of the ovariectomized group, although BMD of the distal femur and proximal tibia was significantly lower in the spirulina-treated groups than in the ovariectomized group after a 6 week-experimental period. BMD of the femur and tibia was not affected by treatment with any dose of spirulina in hindlimb-unloaded mice. These results suggest that the intake of spirulina decreased BMD in the trabecular bone of rodents under estrogen-deficient conditions.

The effects of dietary supplementation of algae and synthetic astaxanthin on body astaxanthin, survival, growth, and low dissolved oxygen stress resistance of kuruma prawn, Marsupenaeus japonicus Bate

Natural carotenoids from astaxanthin containing alga Haematococcus pluvialis (H) and a non-astaxanthin carotenoid-containing alga Spirulina pacifica (S), and a synthetic astaxanthin Carophyll Pink (A) were supplemented in formulated diets at two concentrations, 50 (I) and 100 (II) mg kg −1, resulting in seven pigmented diets HI, SI, AI, HII, SII, AII, and HS (H-50 mg kg −1+S-50 mg kg −1). Formulated diet without carotenoid supplementation served as a control (C). The different diets were fed to juvenile kuruma prawn Marsupenaeus japonicus for 9 weeks. Dietary carotenoid effects on survival, growth, and pigmentation were compared by the treatment individually or collectively. A low dissolved oxygen stress test was conducted 2 weeks later and prawns' survival time and oxygen consumption rate were also compared among treatments. After 9 weeks' rearing, C-fed prawn had significantly lower survival rate than the pigmented diets-fed prawns. No difference in weight gain was found among all prawns. C-fed prawn had 66.4% less flesh astaxanthin (FA) and 75.5% less shell astaxanthin (SA) than the pigmented diets-fed prawns. I-fed (AI, HI, and SI) prawns had 31.1% less FA and 29.6% less SA than II-fed (AII, HII, SII, and HS) prawns. No significant differences were found in the comparisons by other categories. The use of these three sources of carotenoids for pigmentation in crustacean was discussed along carotenoid conversion, deposition, digestibility, and absorption. When subjected to low dissolved oxygen stress, C-fed prawn had higher oxygen consumption rate (OCR) and shorter survival time (ST) than the prawns fed the pigmented diets. No differences in OCR or ST were found in the comparisons by other categories.

The modes of glucose action on photosynthesis of Spirulina platensis (Nordst.) Geitl. (Cyanophyta) as revealed by chlorophyll fluorescence analysis

The effects of a) glucose, b) mannose and 2-deoxyglucose (glucose analogues capable of triggering hexokinase-mediated photosynthesis repression) and c) sodium citrate on chlorophyll fluorescence parameters of the blue-green alga Spirulina platensis (Nordst.) Geitl. were investigated. The addition of glucose evoked, at first, the lowering of all photochemical fluorescence quenching parameters (FV/FM, FV'/FM', qP and ΦPS II). The decrease correlated with glucose concentration. The inhibition of photochemical activity relaxed after the third day of the experiment, perhaps, as the consequence of glucose utilization. If the concentration of glucose in the cultural medium was high enough (50 mM), on the seventh day all the indices of photochemical quenching began to diminish again, at which time qP reduction was more significant than that for FV'/FM'. The relief of glucose repressive effects was light-dependent. Glucose analogues caused the decrease in only one photochemical quenching parameter, qP. Unlike mannose, the effect of 2-deoxyglucose was more pronounced and did not weaken till the end of experiments. Nonphotochemical quenching fluorescence parameters (qN and NPQ) were also reduced under monosaccharide treatment. The influence of sodium citrate on chlorophyll fluorescence parameters was negligible. Therefore, the multiplicity of glucose effects in the course of inhibition of S. platensis photosystem II activity was demonstrated, while hexokinase-dependent repression mechanism was playing only a partial role and resulting in the blocking of electron flow from photosystem II reaction centers down the electron transport chain.

除草剤および無機水銀の藍藻（Ｓｐｉｒｕｌｉｎａ ｐｌａｔｅｎｓｉｓ）への影響評価に対する遅延蛍光時間分解計測技術の応用

We have investigated the influences of herbicides and mercury on the blue-green alga Spirulina platensis by analyzing the long-term behavior of S.platensis delayed fluorescence(DF). S.platensis DF was recorded as a decay curve, and change in the DF intensity with time was analyzed. The decay curve was found to be composed of two components. The first component peaked just after excitation (P1). The second component peaked at approximately 30 seconds after excitation (P2). When the alga was exposed to toxicants, the intensities of P1 (CP1) and P2 (CP2), and the time of P2 appearance (TP2) varied notably. The tested herbicides, diuron (DCMU) and simazine (CAT), increased CP1, and decreased CP2. Mercury increased TP2 and CP1, and decreased CP2. During the measurements at 30 min after the exposure, the effect of DCMU was detectable at a minimum of 0.1μg·l-1, that of CAT at 0.25μg·l-1 and that of mercury at 20μg·l-1.Furthermore, when the alga was exposed to both herbicides and mercury, the influences were combined. This study indicates that the analysis of the long-term behavior of DF of an alga may be useful in the rapid detection of toxicants in contaminated waters.

Proteoglycans Released from Cultured Bovine Aortic Endothelial Cell Layers by Sodium Spirulan Are Both Perlecan and Biglycan

Sodium spirulan (Na-SP) is a sulfated polysaccharide isolated from the blue-green alga Spirulina platensis. Na-SP has anticoagulant and fibrinolytic properties in vitro, including activation of heparin cofactor II, enhancement of vascular endothelial cell fibrinolytic activity and stimulation of endothelial proteoglycan (PG) release. In the present study, we investigated the types of endothelial PGs whose release is stimulated by Na-SP. Na-SP stimulated the PG release in a dose- and time-dependent manner. However, heparin, dextran sulfate and hyaluronan stimulated the release of heparan sulfate PGs rather than chondroitin/dermatan sulfate PGs, whereas the release of both types of PGs was strongly stimulated by Na-SP. Sepharose CL-6B chromatography of [35S]sulfate-labeled PGs showed that PGs were partially released after partial degradation of the core proteins without a change in chain length of the glycosaminoglycan chains after Na-SP treatment. On the other hand, SDS-polyacrylamide gel electrophoresis and Western blot analysis of the PG core proteins indicated that the Na-SP-releasable PGs are both a large heparan sulfate PG, perlecan, and a small chondroitin/dermatan sulfate PG, biglycan, without change in the size of the core proteins. Taken together, these results suggest that Na-SP stimulates the endothelial release of both perlecan and biglycan with the intact structures, possibly by mechanisms different from those of heparin, dextran sulfate and hyaluronan; a part of the PG core proteins may be degraded after Na-SP treatment. Since perlecan and biglycan have antithrombin activities, the present data support the hypothesis that Na-SP may enhance local anticoagulant activity in the liquid phase on the endothelium via stimulation of endothelial PG release.

Biosorption of Cr 3+, Cd 2+ and Cu 2+ ions by blue–green algae Spirulina sp.: kinetics, equilibrium and the mechanism of the process

The process of biosorption of heavy metal ions (Cr 3+, Cd 2+, Cu 2+) by blue–green algae Spirulina sp. is discussed in this paper. Spirulina sp. was found to be a very efficient biosorbent. The aim of the present study was to investigate quantitatively the potential binding sites present at the surface of Spirulina sp., using both potentiometric titrations and adsorption isotherms. The kinetic experiments showed that the process equilibrium was reached quickly, in less than 5–10 min. It was found that the equilibrium dependence between biosorption capacity and bulk metal ion concentration could be described with Langmuir equation. This suggests that the mechanism of biosorption is rather chemisorption than physical adsorption and was further confirmed by the low surface area associated with physical adsorption and by the presence of cations that appeared in the solution after biosorption. The maximum contribution of physical adsorption in the overall biosorption process was evaluated as 3.7%. It was proposed that functional groups on the cell surface contributed to the binding of metal ions by a biosorbent via equilibrium reaction. Three functional groups capable of cation exchange were identified on the cell surface. The biomass was described as weakly acidic ion exchanger. Since deprotonation of each functional group depends on pH, the process of biosorption is strongly pH-dependent. This was confirmed in the biosorption experiments carried out at different pH. The contribution of functional groups in the biosorption process was confirmed by chemical modification of the groups. Chemically blocked groups did not show neither biosorption nor ion-exchange capabilities. It has been shown that growth conditions can affect the metal adsorption properties of microalgae. The paper also discusses desorption characteristics of the biosorbent. The criteria for desorption were high elution efficiency and preservation of biosorptive properties. Desorbent that possessed these characteristics was nitric acid.

Sodium spirulan as a potent inhibitor of arterial smooth muscle cell proliferation in vitro

Sodium spirulan (Na-SP) is a sulfated polysaccharide with M r ∼220,000 isolated from the blue-green alga Spirulina platensis. The polysaccharide consists of two types of disaccharide repeating units, O-hexuronosyl-rhamnose (aldobiuronic acid) and O-rhamnosyl-3- O-methylrhamnose (acofriose) with sulfate groups, other minor saccharides and sodium ion. Since vascular smooth muscle cell proliferation is a crucial event in the progression of atherosclerosis, we investigated the effect of Na-SP on the proliferation of bovine arterial smooth muscle cells in culture. It was found that Na-SP markedly inhibits the proliferation without nonspecific cell damage. Either replacement of sodium ion with calcium ion or depolymerization of the Na-SP molecule to M r ∼14,700 maintained the inhibitory activity, however, removal of sodium ion or desulfation markedly reduced the activity. Heparin and heparan sulfate also inhibited vascular smooth muscle cell growth but their effect was weaker than that of Na-SP; dextran sulfate, chondroitin sulfate, dermatan sulfate and hyaluronan failed to inhibit the cell growth. The present data suggest that Na-SP is a potent inhibitor of arterial smooth muscle cell proliferation, and the inhibitory effect requires a certain minimum sequence of polysaccharide structure whose molecular conformation is maintained by sodium ion bound to sulfate group.

Micronutrient content of certain tropical conventional and unconventional feed resources of Southern India.

The ash, silica and certain important micronutrients were estimated in conventional and unconventional feed and fodder resources available in Southern India. Commonly used dry roughages, such as paddy straw, ragi straw, maize kadbi/stalk, jowar kadbi/stalk, bajra stalk and wheat straw, were high in ash (9.9% +/- 0.77%) and silica (6.4% +/- 0.65%) and low in most of the other micronutrients, except iron, with paddy straw containing most silica (>9%). Cultivated non-leguminous (maize, jowar) and improved green crops (hybrid napier, guinea, green panic, NB-21, CO-1) were also high in ash (10.5% +/- 0.60% and 12.5% +/- 0.51%) but were moderate sources of P, Mg and Cu and good sources of Zn (98 +/- 13.8 ppm and 55 +/- 6.7 ppm). Leguminous green fodders (stylosanthus, lucerne, cow pea, soyabean) were excellent sources of Ca (1.9% +/- 0.16%), Mg (0.40% +/- 0.05%), Cu (30 +/- 5.2 ppm), Zn (121 +/- 14.7 ppm) and Fe (1234 +/- 166 ppm) and moderate sources of P. Mixed local grasses and weeds were high in silica (6.9% +/- 1.00%) but were good sources of Cu, Zn and Fe. Cereal grains (maize, wheat, rice, ragi) were low in ash (2.9% +/- 0.33%) and were relatively poor sources of Ca (0.22% +/- 0.03%), Mg (0.19% +/- 0.03%) and Cu (13 +/- 3.1 ppm). Pulses were low to medium sources of most minerals and good sources of Fe (1230 +/- 293 ppm). Oil seed cake/extractions (groundnut cake, cotton seed cake, soyabean meal, sunflower cake, safflower cake) and cereal by-products (rice polish, rice bran, wheat bran) were excellent sources of P (1.1% +/- 0.47% and 2.3% +/- 0.19%) and good sources of Zn (65 +/- 3.9 ppm and 66 +/- 10.7 ppm) and Fe (938 +/- 130 ppm and 662 +/- 126 ppm). Among the unconventional feeds screened, orange peel, sunflower heads, meat meal, rubber seed cake, spirulina algae and sea weeds contained plentiful Ca, Zn and Fe: tree leaves/top feeds (mulberry, erythrina, glyricidia, banana, subabul, groundnut haulms) were excellent sources of Ca (1.5% +/- 0.13%), Zn (120 +/- 22.9 ppm) and Fe (1033 +/- 133 ppm) but relatively poor sources of P. Soyabean husk, cocoa seed husk, rubber seed cake and meat meal were moderate to good sources of P (1.0% and 0.33%). The high Zn and Fe values of most feeds/fodders were probably due to soil contamination. This account of the micronutrient content of feed/fodder resources should help in strategic supplementation intended to alleviate local deficiencies.

In vitro 검출시스템을 이용한 해양생물 추출물로부터 에스트로겐 활성 검증

천연물에 포함되어 있는 에스트로겐 효과를 가지는 성분의 생체 내에서의 직접적인 효과를 검정하기 위하여, 에스트로겐 수용체를 발현하는 것으로 알려진 인체 유방암 세포주 MCF7에 에스트로겐에 반응성을 나타내도록 고안된 CAT 리포터 플라스미드를 도입한 in vitro 검출시스템을 사용하여 에스트로겐 활성을 측정하였다. 이미 여러 분야에서 그 기능성의 연구가 활발히 진행되고 있는 광합성 조류인 스피루리나(spirulina)와 파래 등의 해양식물을 대상으로 에스트로겐 반응 리포터 시스템을 이용하여 에스트로겐 활성을 측정하였다. 그 결과, 스피루리나 에탄올 추출물의 CAT 활성은 <TEX>$500\mug/ml\; 와\; 50 \mug/ml$</TEX>의 농도에서 표준물질인 <TEX>$17\beta-estradiol$</TEX>의 농도 <TEX>$10^{-8}$</TEX> M과 비슷한 정도의 에스트로겐 활성 효과를 나타내었고, <TEX>$5\mug/ml$</TEX>의 농도에서는 표준물질인 <TEX>$17\beta-estradiol$</TEX>의 농도 <TEX>$10^{-10}$</TEX> M과 비슷한 정도의 에스트로겐 활성 효과를 나타내었다. 하지만 파래 추출물의 경우에는 에탄올을 처리한 대조군과 비교하여 유의한 CAT활성 변화를 나타내지 않았다 한편, 불가사리와 새우 등의 해양동물을 대상으로 한 실험에서는 에탄올을 처리한 대조군과 비교하여 유의한 CAT 활성 변화를 나타내지 않았다. 이 연구 결과로 광합성 조류인 스피루리나에 에스트로겐 활성을 효과적으로 나타내는 생리활성성분이 포함되어 있을 수 있다는 가능성을 확인하였다. In order to verify the occurrence of an estrogenic compound in natural products, the estrogenic activity was measured using an in vitro detection system. For this system, human breast cancer cell line MCF7 was transfected using an estrogen responsive CAT reporter plasmid. Estrogenic activities of photosynthetic algae spirulina and sea lettuce were evaluated using this system. Estrogenic activities of a <TEX>$500\mug/ml\; and\; 50 \mug/ml$</TEX> ethanol extracts of spirulina were as much as that of <TEX>$10^{-8}$</TEX>M standard solution (17<TEX>$\beta$</TEX>-estradiol) and activity of <TEX>$5\mug/ml$</TEX> ethanol extract of spirulina was as much as that of <TEX>$10^{-10}$</TEX> M standard solution. However, no significant estrogenic activity was observed using sea lettuce extract. Estrogenic activities of marine animals, such as star fish and shrimp, were also evaluated using this system, however, no significant estrogenic activity was observed in these extracts. In this result, it is confirmed that spirulina extract possesses estrogenic compound.

Spirulina Species as a Source of Carotenoids and a-Tocopherol and its Anticarcinoma Factors

In the present study blue-green alga Spirulina platensis and Spirulina maxima were grown in batch culture at different nitrogen and NaCl concentrations, respectively. Both species were found to respond to nitrogen deficiency and high NaCl level by accumulation of large amounts of commercially important chemicals such as carotenoids and tocopherols. The higher carotenoids and a-tocopherol contents was obtained when Spirulina sp grown at low nitrogen level (51 ppm N), with values ranged from 19.82 to 24.1 mg g-1and from 533.2 to 978.5 ?g Kg-1 (dry weight, d.w.), respectively. Whilst, these values in cells grown in free nitrogen medium were ranged from 30.15 to 31.13 mg g-1and from 960.4 to 1325.7 ?g Kg-1 (d.w), respectively. The high performance liquid chromatography (HPLC) elution patter of total caroteniods extracted from S. platensis and S maxima culture contained a-carotene (49.6 to 319.5 ?g g-1lutein (0.06 to17.21 ?g g-1, astaxanthin (6.61 to 160.27 ?g g-1,zeaxanthin (1.25 to 18.55 ?g g-1) and cryptoxanthin (1.41 to 20.13 ?g g-1). S. maxima accumulated a large amount of cryptoxanthin and zeaxanthin than that found in S. platensis. The effect of Spirulina species extracts containing various carotenoid compounds and tocopherols on the viability of Ehrlich ascites carcinoma cells (EACC) were evaluated. All algae extracts at different concentration of 200 and 400 ppm significant reduced the cell viability ranged from 89.11 to 5.25%. These extracts did not induce any significant changes in DNA fragmentation of treated EACC compared with untreated cells. But lactate dehydrogenase (LDH) and glutathione-S- transferase (GST) enzyme activities and glutathione level in treated EACC were significantly higher than that in untreated cells. These finding suggest that algae extracts may be reduce cell viability by other mechanism such as membrane lyases instead of apoptosis. Thus, Spirulina extract rich in carotenoids and tocopherols could be used as chemopreventive agents since they are relative non-toxic.

Differential Effects of Sodium Spirulan on the Secretion of Fibrinolytic Proteins from Vascular Endothelial Cells: Enhancement of Plasminogen Activator Activity

Sodium spirulan (Na-SP) is a sulfated polysaccharide with Mr ~220000 isolated from the blue-green alga Spirulina platensis. Na-SP influences the blood coagulation-fibrinolytic system by activation of heparin cofactor II in vitro, although it has been incompletely understood whether the polysaccharide can act on vascular endothelial cell functions. In the present study, we investigated the effects of Na-SP on the fibrinolytic activity of human coronary endothelial cells in a culture system. It was found that Na-SP enhances the activity of tissue-type and urokinase-type plasminogen activators in the conditioned medium of the cells through induction of urokinase-type plasminogen activator secretion and inhibition of plasminogen activator inhibitor type 1 (PAI-1) secretion. The inhibitory effect of Na-SP on PAI-1 secretion was maintained even when sodium ion was removed or replaced by calcium ion, while it disappeared with desulfation, indicating that metal ion is not required but the sulfate group is essential for the inhibition of endothelial PAI-1 secretion by Na-SP. The present study revealed that Na-SP not only shows a strong antithrombin effect through activation of heparin cofactor II but also exhibits a fibrinolytic property through differential effects on endothelial fibrinolytic protein secretion.

Cyst-based toxicity tests. XI. Influence of the type of food on the intrinsic growth rate of the rotifer Brachionus calyciflorus in short-chronic toxicity tests.

As important members of zooplankton communities worldwide, rotifers are used extensively in ecotoxicological research. Chronic rotifer tests are, however, dependent on live algal food which adds to the complexity, the variability and the costs of these bioassays. To bypass the former problem, experiments have been undertaken with the freshwater rotifer Brachionus calyciflorus, to determine their intrinsic growth rate (r) when fed for 48 h on a mixture of green algae (Raphidocelis subcapitata recently renamed Pseudokirchneriella subcapitata) obtained from algal beads stored for different periods of time, and other inert foods. All tests have been performed in disposable multiwells, in 1 ml cups each inoculated with 1 rotifer freshly hatched from dried cysts. The majority of the growth tests was performed in eight replicates. The investigations revealed that microalgae from algal beads stored for up to one year, in darkness, at 4 degrees C, supplemented with dried blue-green algae (Spirulina) gave satisfactory rotifer reproduction. The intrinsic growth rates of the rotifers, were, however, dependent on the storage time of the algal beads; the highests r's (0.7-0.8) were obtained with algae from beads not older than four months. Growth tests with combinations of P. subcapitata and other inert feeds revealed that the enrichment food Selco used in aquaculture, also gave the same reproductive output as the combination microalgae/Spirulina. A rotifer growth experiment with 18 replicates showed that the variation coefficient is below 20% when the tests comprise eight replicates. This study demonstrated that microalgae from beads, supplemented by other inert food, open the door for a practical and cost-effective short-chronic rotifer test, which is totally independent of the culturing of both the test species and its live food.

Repair of wounded monolayers of cultured bovine aortic endothelial cells is inhibited by calcium spirulan, a novel sulfated polysaccharide isolated from Spirulina platensis

Calcium spirulan (Ca-SP) is a novel sulfated polysaccharide isolated from a blue-green alga Spirulina platensis. Ca-SP inhibits thrombin by activation of heparin cofactor II. Therefore, it could serve as an origin of anti-atherogenic medicines. Since maintenance of vascular endothelial cell monolayers is important for prevention of vascular lesions such as atherosclerosis, the effect of Ca-SP at 20 μg/ml or less on the repair of wounded bovine aortic endothelial cell monolayers in culture was investigated in the present study. When the monolayers were wounded and cultured in the presence of Ca-SP, the polysaccharide inhibited the appearance of the cells in the wounded area. The inhibition was also observed even when the repair was promoted by excess basic fibroblast growth factor, which is one of the autocrine growth factors that are involved in the endothelial cell monolayer maintenance. On the other hand, Ca-SP inhibited the cell growth and the incorporation of [ 3H]thymidine into the acid-insoluble fraction of proliferating endothelial cells, suggesting that Ca-SP inhibits endothelial cell proliferation. From these results, it is concluded that Ca-SP may retard the repair process of damaged vascular endothelium through inhibition of vascular endothelial cell proliferation by induction of a lower ability to respond to stimulation by endogenous basic fibroblast growth factor.

Toxic effect of triphenyltin chloride on the alga Spirulina subsalsa

AbstractA previous study on the deleterious effect of triphenyltin chloride (TPTCl) on the alga Spirulina subsalsa reported on four physiological and biochemical indices (or parameters): growth rate, chlorophyll content, phycocyanin content and nitrate reductase activity. In the present study, further research was performed to confirm the findings reported in the previous paper, using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The SEM images show significant changes in the screw‐pitch of S. subsalsa, suggesting that TPTCl may damage the inheritance characteristics of S. subsalsa. The TEM images illustrate that the external pectin theca, limiting membrane and inter photosynthetically active lamella in the S. subsalsa cell are those targets that can be easily damaged. Reversible and irreversible cell damage (cell necrosis) are also observed. Copyright © 2002 John Wiley &amp; Sons, Ltd.

Inhibition of the Association of Proteoglycans with Cultured Vascular Endothelial Cell Layers by Calcium and Sodium Spirulan.

Vascular endothelial proteoglycans exhibit an antithrombogenic activity by activating antithrombin III and heparin cofactor II on the luminal surface of the vascular wall. Calcium spirulan (Ca-SP) is a novel sulfated polysaccharide isolated from the blue-green alga Spirulina platensis. Since Ca-SP exhibits antithrombin activity by activation of heparin cofactor II, we hypothesized that the polysaccharide may influence the metabolism of anticoagulant proteoglycans synthesized by endothelial cells. When cultured bovine aortic endothelial cells were treated with Ca-SP (50 μg/ml or less) in the presence of [35S]sulfate for 24 hr, the accumulation of labeled proteoglycans in the cell layer was decreased but that in the conditioned medium was significantly increased, indicating that Ca-SP inhibits the association of proteoglycans with vascular endothelial cell layers. Na-SP, which was prepared by replacement of calcium ion with sodium ion, showed an equal effect. When the endothelial cells were labeled with [35S]sulfate and then treated with Ca-SP (5 μg/ml or more) for 1 hr in the absence of [35S]sulfate, the percentage of [35S]sulfate-labeled proteoglycans released into the medium was markedly increased by Ca-SP. DEAE-Sephacel ion exchange chromatography of [35S]sulfate-labeled proteoglycans released into the medium from Na-SP-treated cells indicated that Na-SP stimulates the release of both heparan and chondroitin/dermatan sulfate proteoglycans from the cell layer. Taking these results together it is suggested that Ca-SP and Na-SP promote the release of proteoglycans from vascular endothelial cells by inhibiting the association of the macromolecules with the cell layer.

Secretion of Free Fatty Acids by Prokaryotic and Eukaryotic Algae at Optimal, Supraoptimal, and Suboptimal Growth Temperatures

The paper describes the composition of extracellular free fatty acids (FFAs) and intracellular fatty acids (FAs) in the enrichment cultures of the prokaryotic alga Spirulina platensisand the eukaryotic alga Chlorella vulgarisgrown at optimal, supraoptimal, and suboptimal growth temperatures. With increasing growth temperature, the degree of unsaturation of the intracellular FAs of both algae decreased, while that of the extracellular FFAs of S. platensisincreased. The composition of the extracellular FFAs of C. vulgarispractically did not depend on the growth temperature.

The behaviour of protein preparations from blue-green algae ( Spirulina platensis strain Pacifica) at the air/water interface

The surface tension of a protein sample isolated from the blue-green algae (cyanobacteria) Spirulina platensis strain Pacifica was studied using the Wilhelmy plate method. The isolated material was characterised by determining the protein and lipid content, SDS-PAGE electrophoresis, isoelectric focusing, and visible spectroscopy. The protein is capable of reducing the interfacial tension at the aqueous/air interface already at relatively lower bulk concentrations compared to common food proteins. The surface tension of the protein preparation seems to be quite independent of pH, which indicates that electrostatic interactions are of minor importance for the interfacial behaviour. We have also separated out fractions with different interfacial properties by centrifugation. When the protein was spread at the air/aqueous interface, the pressure area isotherm somewhat resembles those recorded for lipids, with a higher collapse pressure than usually observed for proteins. The interfacial behaviour of extracted lipids confirms that remaining traces of lipids in protein powder have only a minor influence on the surface activity of Spirulina protein. The surface-active components are likely to be protein and/or protein-pigment complexes rather than individual protein molecules.