Action of Spirulina platensis on bacterial viruses

The impact of the biomass of the blue-green microalga (cyanobacterium) S. platensis on bacteriophage T4 (bacterial virus) has been evaluated. The study revealed that the addition of S. platensis biomass into the agar nutrient medium, followed by sterilization with 2% chloroform and thermal treatment, produced an inhibiting or stimulating effect on the reproduction of the bacteriophage in Escherichia coli B cells, depending on the concentration of S. platensis and the multiplicity of phage infection, as well as on the fact whether the microalgae were added during the first cycle of the development of the virus. The reproduction of the bacteriophage in E. coli B was influenced by the method and duration of the sterilization of the nutrient medium with S. platensis.     

Improving Spirulina platensis biomass yield using a fed-batch process

Increasing interest is being shown in the cyanobacterium Spirulina platensis because of its nutritional properties when used as food supplement and possible therapeutic effects. One of the most important areas being studied is the development of alternative nutrient sources which can be used to decrease the production costs of commercially produced S. platensis and obtain high productivity. Water from Mangueira Lagoon (Rio Grande do Sul State, Brazil) has high levels of carbonates and a high pH and has the potential to be used as a culture medium for S. platensis, although some nutrient supplementation may be required. We tested the effect of unsupplemented Mangueira Lagoon water (MLW) or MLW supplemented with 1.125 or 2.250 mg/l of urea and/or 21 or 42 mg/l of sodium bicarbonate on the growth of S. platensis in fed-batch culture using a 3(2) factorial design and found that there the addition of 1.125 mg/l of urea resulted in a 2.67 fold increase times in the final biomass concentration of S. platensis.     

Detection of biologically active substances with antagonistic and stimulating activity in Spirulina platensis

The results of studies on the detection of biologically active substances (BAS) in biomass dilutions and culture fluid of Spirulina platensi and algae (Chlorella, Fucus, Laminaria) by the agar diffusion method are presented. After the sterilization of the solutions with chloroform (CF) a substance with lysozyme-like activity and 2 substances with antagonistic activity deep in agar and on its surface were detected with the use of the micrococcal indicator strain. After CF treatment, depending on the concentration of S. platensis strains, a compound stimulating the growth of bacteria and sensitive to heat treatment was detected. BAS were also detected with the use of other indicator cultures.     

Effect of microalgae on viability of microorganisms in the natural and artificial environment

The data of literature on complicated relationships between microorganisms and microalgae in algobacterial associations with microalgae often playing the leading role are analyzed. Under these conditions inhibiting and stimulating substances synthesized by microalgae, as well as their nutritional value, may have an essential impact on the state of the bacterial population. Apparently that microalgae may become the main substrate in the development of new culture media (ecologically pure culture media, media for the reversion of the noncultured forms of bacteria into the vegetative state, media for the prolonged preservation of microbes in the noncultured form).     

Biological activity of Spirulina

In this review information of Spirulina platensis (SP), a blue-green alga (photosynthesizing cyanobacterium) having diverse biological activity is presented. Due to high content of highly valuable proteins, indispensable amino acids, vitamins, beta-carotene and other pigments, mineral substances, indispensable fatty acids and polysaccharides, PS has been found suitable for use as bioactive additive. SP produces an immunostimulating effect by enhancing the resistance of humans, mammals, chickens and fish to infections, the capacity of influencing hemopoiesis, stimulating the production of antibodies and cytokines. Under the influence of SP macrophages, T and B cells are activated. SP sulfolipids have proved to be effective against HIV. Preparations obtained from SP biomass have also been found active against herpesvirus, cytomegalovirus, influenza virus, etc. SP extracts are capable in inhibiting cancerogenesis. SP preparations are regarded as functional products contributing to the preservation of the resident intestinal microflora, especially lactic acid bacilli and bifidobacteria, and to a decrease in the level of Candida albicans. The biological activity of SP with respect to microorganisms holds good promise for using these microalgae as components of culture media.     

益生菌的多重抗病毒作用及其机制

病毒性疾病对人类和动物健康造成了重大威胁。由于现有的免疫接种和抗病毒疗法的局限性,开发安全、广谱、廉价的新型抗病毒制剂极为迫切。益生菌是摄入后能对机体产生多种有益作用的活性微生物,其抗病毒作用及潜在机制是当前的研究热点。本文介绍了益生菌通过促进肠道细胞的紧密连接和产生有利物质来维护机体黏膜屏障;与病毒竞争结合靶点或直接捕获并抑杀病毒;刺激机体免疫系统,调节固有免疫反应和适应性免疫反应;分泌具有抗病毒作用的代谢产物来发挥抗病毒作用及其作用机制,以期为益生菌的抗病毒相关研究提供参考。     

Spirulina platensis growth in open raceway ponds using fresh water supplemented with carbon,nitrogen and metal ions

To investigate the feasibility of using fresh water from Mangueira Lagoon (Rio Grande do Sul, Brazil) for biomass production in open raceway ponds (0.7 m long, 0.18 m wide, 0.075 m deep) we studied the influence of nutrient addition (carbon as sodium bicarbonate, nitrogen as urea, phosphate, sulfate, ferric iron, magnesium and potassium) on the growth rate of the cyanobacteria Spirulina platensis using a 22 factorial design. In unsupplemented lagoon water production of S platensis was 0.78 +/- 0.01 g/l (dry weight basis) while the addition of 2.88 g/l of sodium bicarbonate (without added urea, phosphate, sulfate or metal ions) resulted in 0.82 +/- 0.01 g/l after 400 hours of culture. The further addition of phosphate and metal ions resulted in growth for up to 750 h and a final S. platensis biomass of 1.23 +/- 0.04 to 1.34 +/- 0.03 g/l.     

Simultaneous cultivation of Spirulina platensis and the toxigenic cyanobacteria Microcystis aeruginosa

Mangueira Lagoon, located in the extreme south of Brazil, has water with physicochemical characteristics such as alkaline pH and carbonate levels propitious for the growth of the cyanobacterium Spirulina platensis. Previously published studies have shown that Mangueira Lagoon water supplemented with small quantities of carbon and nitrogen is suitable for S. platensis cultivation and can significantly reduce production costs. We studied mixed cultures of Spirulina platensis and the toxic cyanobacterium Microcystis aeruginosa using a 2(3) factorial design in which the three factors were the initial biomass concentration of S. platensis and M. aeruginosa and the type of culture medium (100% Zarrouk's medium or 80% Mangueira Lagoon water plus 20% Zarrouk's medium). The highest S. platensis maximum specific growth rate (mu(max)) occurred in the culture with the highest M. aeruginosa biomass concentration and when undiluted culture medium was used (micro(max) = 0.283 d(-1)). The highest M. aeruginosa specific death rate (k) was obtained in the presence of S. platensis (k = 0.555 d(-1)) and was independent of the initial M. aeruginosa biomass concentration and culture medium, demonstrating that S. platensis cultures are not susceptible to contamination by M. aeruginosa. The culture medium had no significant influence (p > 0.05) on S. platensis micro(max) values, indicating that production costs could be reduced by using a medium consisting of 80% Mangueira Lagoon water plus 20% Zarrouk's medium.     

Bioactive secondary metabolites produced by microorganisms associated with plants

In the past few decades groups of scientists have focused their study on relatively new microorganisms called endophytes. By definition these microorganisms, mostly fungi and bacteria, colonise the intercellular spaces of the plant tissues. The mutual relationship between endophytic microorganisms and their host plants, taxanomy and ecology of endophytes are being studied. Some of these microorganisms produce bioactive secondary metabolites that may be involved in a host-endophyte relationship. Recently, many endophytic bioactive metabolites, known as well as new substances, possesing a wide variety of biological activities as antibiotic, antitumor, antiinflammatory, antioxidant, etc. have been identified. The microorganisms such as endophytes may be very interesting for biotechnological production of bioactive substances as medicinally important agents. Therefore the aim of this review is to briefly characterize endophytes and summarize the structuraly different bioactive secondary metabolites produced by endophytic microorganisms as well as microbial sources of these metabolites and their host plants.     

Factors indicating culture status during cultivation of Spirulina (Arthrospira) platensis

Factors indicating culture status of two Spirulina platensis strains were monitored in a batch mode cultivation for 36 days. Changing mode in all factors showed a common turning point, indicating shift of cell or culture status. Mean biomass productivity was highly sustained until day 22, chlorophyll a concentration peaked on day 22, pH value was >12 on day 22, coil number was abruptly shortened on day 22, and floating activity was sustained at greater than 79% after day 22, indicating that day 22 is a criterion reflecting phase-transfer in cell physiology in a batch culture system. Many of these changes may have been caused by increased pH, suggesting that pH control is essential for mass production of S. platensis. Fluctuations in floating activity were likely induced by the number of cellular gas vacuoles. Consequently, coil number per trichome and floating activity of S. platensis could readily act as simple indicators for determination of culture status or harvesting time of cells.     

Microbial oxidation of terfenadine and ebastine into fexofenadine and carebastine

The oxidation of tert-butyl-phenyl group of title compounds by some microorganisms was studied. We have optimized the conditions of culture to increase the formation of acid metabolites and to avoid the formation of side products. We showed that an oxidative activity is induced by soybean peptones in Streptomyces platensis. The biologically active compounds, fexofenadine and carebastine, are produced in good yield (86-95%) by Absidia corymbifera.     

Effect of selected bacteria on mycelial transformation of cells of Candida albicans

Influence of selected bacteria representing typical physiological flora of mucous membranes of man on transformation of Candida albicans from yeast phase to mycelial phase was evaluated, E. coli, S. viridans and S. faecalis inhibited to different degree mycelial transformation of fungal cells. A degree of inhibition in the case of E. coli was proportional to the period of preliminary culture of strains in medium containing serum while streptococci inhibited mycelial transformation mainly after 4 and 24 hr of preliminary culture. Production of factor(s) inhibiting mycelial transformation of C. albicans by E. coli was induced by direct contact with fungal cells and by low molecular weight substances produced by C. albicans. Streptococci produced inhibiting factors even when fungal cells or their metabolites were absent in the medium.     

Influence of gaseous metabolites of soil bacteria on the multiplication of Listeria monocytogenes and Yersinia pseudotuberculosis

The influence of gaseous metabolites of saprophytic soil bacteria on the growth and multiplication of L. monocytogenes and Y. pseudotuberculosis was studied. The study revealed that all cultures under study exhibited selectively both inhibiting and stimulating action on the multiplication of test cultures. Bacteria of the genera Pseudomonas and Acinetobacter showed the highest inhibiting activitywith respect to the test cultures. Volatile metabolites of bacteria of the genus Aeromonas showed the highest stimulating activity. Methanol, according to the data of chromatographic analysis, supposedly played the main role in this process and was contained in the volatile substances of Aeromonas bacteria in greater amounts than in the volatile substances of Pseudomonas bacteria.     

Production of cytokinin-like substances by mycorrhizal fungi of pine (Pinus sylvestris L.) in cultures with and without metabolites of actinomycetes

Studies on the effect of post culture liquids of actinomycetes on cytokinin-like substances production by mycorrhizal fungi have revealed that actinomycete metabolites inhibited or stimulated the synthesis of these compounds. The results of chromatographic analyses suggest, that substances stimulating the soybean callus are likely to be: riboside 6 (gamma, gamma-dimethylallylamino) purine and riboside zeatin. Using gas chromatography it was confirmed that both substances are produced by Rhizopogon luteolus. Paxillus involutus synthesizes probably besides the two substances also zeatin, as appears from the data obtained by column chromatography.     

Nitrification of human urine for its stabilization and nutrient recycling

Nitrification of human urine performed for its stabilization, and culture of Spirulina platensis in the nitrified human urine were investigated for nutrient recovery. With daily adjusting to pH 8 and keeping high dissolved oxygen concentration, mean 95.0% of NH(4)-N in human urine can be finally stabilized and oxidized to NO(3)-N. Furthermore, this nitrified human urine seems to be an ideal culture medium for S. platensis. Without pH adjustment, only about 50.0% NH(4)-N could be converted, i.e. NH(4)NO(3) would be formed. Under low dissolved oxygen concentration, mainly short nitrification (from NH(4)-N to NO(2)-N) occurred.     

Soil-borne microorganisms and soil-type affect pyrrolizidine alkaloids in Jacobaea vulgaris

Secondary metabolites like pyrrolizidine alkaloids (PAs) play a crucial part in plant defense. We studied the effects of soil-borne microorganisms and soil-type on pyrrolizidine alkaloids in roots and shoots of Jacobaea vulgaris. We used clones of two genotypes from a dune area (Meijendel), propagated by tissue culture and grown on two sterilized soils and sterilized soils inoculated with 5% of non-sterilized soil of either of the two soil-types. Soil-borne microorganisms and soil-type affected the composition of PAs. By changing the composition rather than the total concentration below and aboveground, plants have a more complex defense strategy than formerly thought. Interestingly, a stronger negative effect on plant growth was found in sterilized soils inoculated with their ‘own’ microbial community suggesting that pathogenic and/or other plant inhibiting microorganisms were adapted to their ‘own’ soil conditions.     

Identification of indole derivatives as self-growth inhibitors of Symbiobacterium thermophilum, a unique bacterium whose growth depends on coculture with a Bacillus sp

Symbiobacterium thermophilum is a syntrophic bacterium whose growth depends on coculture with a Bacillus sp. Recently, we discovered that CO(2) generated by Bacillus is the major inducer for the growth of S. thermophilum; however, the evidence suggested that an additional element is required for its full growth. Here, we studied the self-growth-inhibitory substances produced by S. thermophilum. We succeeded in purifying two substances from an ether extract of the culture supernatant of S. thermophilum by multiple steps of reverse-phase chromatography. Electron ionization mass spectrometry and nuclear magnetic resonance analyses of the purified preparation identified the substances as 2,2-bis(3'-indolyl)indoxyl (BII) and 1,1-bis(3'-indolyl)ethane (BIE). The pure growth of S. thermophilum was inhibited by authentic BII and BIE with MICs of 12 and 7 microg/ml, respectively; however, its growth in coculture with Bacillus was not inhibited by BII at the saturation concentration and was inhibited by BIE with an MIC of 14 microg/ml. Both BII and BIE inhibited the growth of other microorganisms. Unexpectedly, the accumulation levels of both BII and BIE in the pure culture of S. thermophilum were far lower than the MICs (<0.1 microg/ml) while a marked amount of BIE (6 to 7 microg/ml) equivalent to the MIC had accumulated in the coculture. An exogenous supply of surfactin alleviated the sensitivities of several BIE-sensitive bacteria against BIE. The results suggest that Bacillus benefits S. thermophilum by detoxifying BII and BIE in the coculture. A similar mechanism may underlie mutualistic relationships between different microorganisms.     

利用工业废水,废气（CO2）和余热培养的螺旋藻生物学特性研究

本文在国内首次报道了利用生产碱的工厂排放的废水、废气(CO_2)和余热资源大量培养螺旋藻(Spirulina platensis)及在这样的条件下温度、光照和 pH 对螺旋藻生长的影响。指出利用工业废水、废气(CO_2)和余热资源大规模培养螺旋藻是降低生产成本的理想方案之一。同时说明螺旋藻的生产可能在国民经济中发挥的作用及所具有的潜力。     

N-demethylation of lergotrile by Streptomyces platensis.

Thirty-eight microorganisms were screened for their ability to produce metabolites of the semisynthetic alkaloid, lergotrile. A total of five microorganisms were found to biotransform lergotrile, and N-desmethyl lergotrile was detected as the principal metabolite with most organisms. Streptomyces platensis (NRRL 2364) appeared to form the metabolite in highest yield, and a preparative-scale conversion was accomplished with a recovered yield of 50%. Structure proof was accomplished with comparative thin-layer chromatography, mixed melting point, mass spectrometry, and remethylation to lergotrile.     

N-demethylation of lergotrile by Streptomyces platensis.

Thirty-eight microorganisms were screened for their ability to produce metabolites of the semisynthetic alkaloid, lergotrile. A total of five microorganisms were found to biotransform lergotrile, and N-desmethyl lergotrile was detected as the principal metabolite with most organisms. Streptomyces platensis (NRRL 2364) appeared to form the metabolite in highest yield, and a preparative-scale conversion was accomplished with a recovered yield of 50%. Structure proof was accomplished with comparative thin-layer chromatography, mixed melting point, mass spectrometry, and remethylation to lergotrile.