Protección de la Spirulina maxima sobre la citotoxicidad de la hidroxiurea en células embrionarias de ratón / Protection of Spirulina maxima on cytotoxicity of hydroxyurea in mouse embryonic cells / Proteção de Spirulina maxima em citotoxicidade de hidroxiureia em células embrionárias de camundongo

La Spirulina maxima (SP) tiene efectos farmacológicos protectores por su contenido de ficobiliproteínas que están relacionados con su actividad antioxidante. La hidroxiurea (HU) es un fármaco antineoplásico, citotóxico y teratógeno que implica la inducción del estrés oxidativo. El objetivo de este trabajo fue determinar si la SP y su extracto acuoso de proteína (SPE) protegen contra el efecto citotóxico de HU en cultivos celulares primarios a partir de embriones de ratón de once días. Los efectos de SP, SPE e HU sobre la viabilidad celular se determinaron por el ensayo de fluorescencia de resazurina en cultivos celulares de embriones completos de ratones de once días, de encéfalo y de brotes de extremidades anteriores. Se demostró que ni SP ni su extracto provocaron efectos citotóxicos en ninguna concentración ensayada, por lo que se aumentaba la viabilidad celular. Se encontró que las células expuestas a HU de embriones completos y encéfalo mostraron mayor toxicidad que las células de los miembros anteriores. La SP y el SPE protegieron contra la citotoxicidad de HU de una manera dependiente de la concentración hasta 48 h después de la exposición al fármaco. Este efecto podría ser adecuado para prevenir la muerte celular que deriva en un proceso teratogénico, atribuido a sus propiedades antioxidantes.

Spirulina maxima (SP) has protective pharmacological effects that are related to the antioxidant activity due to its phycobiliprotein content. Hydroxyurea (HU) is an antineoplastic, cytotoxic and teratogenic drug, which involves the induction of oxidative stress. The aim of this study was to determine whether SP and its aqueous protein extract (SPE) protect against the cytotoxic effect of HU in primary cell cultures from mouse embryos. The effects of SP, SPE, and HU on cell viability were determined by resazurin fluorescence assay in whole embryo cell cultures, encephalon, and eleven-day-old forehead bud outbreaks. It was shown that neither SP nor its extract caused cytotoxic effects at any concentration tested, increasing cell viability. It was found that cells exposed to HU of whole embryos and encephalon showed higher toxicity than cells of the previous limbs. SP and SPE protected HU cytotoxicity in a concentration-dependent manner up to 48 hours after exposure to the drug. This effect could be adequate to prevent cell death resulting in a teratogenic process attributed to its antioxidant properties.

Spirulina maxima (SP) tem efeitos farmacológicos protetores devido a seu conteúdo de ficobiliproteínas, que estão relacionadas com sua atividade antioxidante. A hidroxiureia (HU) é uma droga antineoplásica, citotóxica e teratogênica, que envolve a indução do estresse oxidativo. O objetivo deste estudo foi determinar se a SP e seu extrato aquoso de proteína (SPE) protegem contra o efeito citotóxico da HU em culturas celulares primárias a partir de embriões de camundongo de onze dias. Os efeitos de SP, SPE e HU na viabilidade celular foram determinados pelo ensaio de fluorescência de resazurina em culturas celulares de embriões inteiros de camundongos de onze dias, de encéfalo e de surtos de extremidades anteriores. Demonstrou-se que nem a SP nem seu extrato causaram efeitos citotóxicos em qualquer concentração testada, aumentando a viabilidade celular. Verificou-se que as células expostas à HU de embriões completos e encéfalo mostraram maior toxicidade do que as células dos membros anteriores. SP e SPE protegem contra a citotoxicidade de HU de forma dependente da concentração até 48 h após a exposição ao medicamento. Esse efeito poderia ser adequado para prevenir a morte celular, que resulta em um processo teratogênico atribuído a suas propriedades antioxidantes.

Principales propiedades inmunomoduladoras y antinflamatorias de la ficobiliproteína C-ficocianina / Main immunomodulatory and anti-inflamatory properties of phycobiliproteins C-phycocyanin

Las ficobiliproteínas son proteínas solubles en agua, que funcionan como pigmentos fotosintéticos accesorios en diferentes organismos tales como las cianobacterias, las algas rojas y las criptomonadas. En el alga verdeazul Spirulina platensis, una de las ficobiliproteínas más abundantes es la C-ficocianina, la cual tiene unido tres cromóforos ficocianobilina mediante un enlace tioéter a cisteínas específicas. La ficocianobilina es un tetrapirrol lineal asociado a la captación de energía solar en estos organismos. La C-ficocianina ha sido empleada en diferentes investigaciones biomédicas como biomarcador, por sus propiedades fluorescentes, y como posible agente terapéutico para el tratamiento de enfermedades asociadas al estrés oxidativo, por sus propiedades antioxidantes, inmunomoduladoras y antinflamatorias. Se ha demostrado que esta proteína aumenta la liberación de interferón gamma en células mononucleares de sangre periférica y modula la producción de citocinas inflamatorias como el factor de necrosis tumoral alfa, entre otras. Además, se ha encontrado que la C-ficocianina tiene efecto inmunomodulador de citocinas que potencian la activación de las células del sistema inmune, como la IL-6 y la IL-1ß, así como la regulación de aproximadamente 190 genes implicados en la inmunidad(AU)

Phycobiliproteins are water-soluble proteins that function as accessory photosynthetic pigments in different organisms such as cyanobacteria, red algae and cryptomonads. In the blue-green algae Spirulina platensis one of the most abundant phycobiliproteins is the C-phycocyanin, which has three phycocyanobilin chromophores linked through a thioether bond to specific cysteine. The phycocyanobilin is a linear tetrapyrrole associated with solar energy absorption in these organisms. The C-phycocyanin has been used in several biomedical researches as a biomarker, for their fluorescence properties, and as a possible therapeutic agent for the treatment of diseases associated with oxidative stress for its antioxidant, anti-inflammatory and immunomodulatory properties. It has been shown that this protein increases the release of interferon gamma in peripheral blood mononuclear cells, and modulates the production of inflammatory cytokines such as tumor necrosis factor among others. Furthermore it has been found that the C-phycocyanin has immunomodulatory effect on cytokines that enhance the activation of immune cells, such as IL-6 and IL-1ß, and the regulation of about 190 genes involved in immunity(AU)

Role of pH on antioxidants production by Spirulina (Arthrospira) platensis

Abstract Algae can tolerate a broad range of growing conditions but extreme conditions may lead to the generation of highly dangerous reactive oxygen species (ROS), which may cause the deterioration of cell metabolism and damage cellular components. The antioxidants produced by algae alleviate the harmful effects of ROS. While the enhancement of antioxidant production in blue green algae under stress has been reported, the antioxidant response to changes in pH levels requires further investigation. This study presents the effect of pH changes on the antioxidant activity and productivity of the blue green alga Spirulina (Arthrospira) platensis. The algal dry weight (DW) was greatly enhanced at pH 9.0. The highest content of chlorophyll a and carotenoids (10.6 and 2.4 mg/g DW, respectively) was recorded at pH 8.5. The highest phenolic content (12.1 mg gallic acid equivalent (GAE)/g DW) was recorded at pH 9.5. The maximum production of total phycobiliprotein (159 mg/g DW) was obtained at pH 9.0. The antioxidant activities of radical scavenging activity, reducing power and chelating activity were highest at pH 9.0 with an increase of 567, 250 and 206% compared to the positive control, respectively. Variation in the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) was also reported. While the high alkaline pH may favor the overproduction of antioxidants, normal cell metabolism and membrane function is unaffected, as shown by growth and chlorophyll content, which suggests that these conditions are suitable for further studies on the harvest of antioxidants from S. platensis.

Crude oil-induced morphological and physiological responses in cyanobacterium Microchaete tenera ISC13

In this research the effects of crude oil on morphological and physiological characterization of the cyanobacterium Microchaete tenera ISC13 were investigated. Isolated cyanobacterium treated with different oil concentrations [control, 1, 2.5, 5 and 7%] in carbonless BG11[0] medium. Morphological characteristics such as morphology of filament, cellular shapes and sizes, relative position of heterocytes and akinetes were described for these treatments. Biometrical and morphological observations carried out by light and scanning electron microscopy. Dimensions of cells did not significantly impress, although a slightly increase in length of vegetative cells was observed in 2.5 and 5% crude oil in comparison to control. With respect to the physiological responses, cyanobacterium growth increased with elevated oil concentration but no changes was observed in chlorophyll content. Phycobiliproteins [PBP], phycocyanin [PC] and allophycocyanin [APC] had the highest rate in control. Increasing crude oil decreased all PBP. This study demonstrated that crude oil doesn't have destructive effect on Microchaete tenera ISC13 and suggest probable potential of this microorganism to use oil hydrocarbons as carbon source

Growth and biopigment accumulation of cyanobacterium Spirulina platensis at different light intensities and temperature

In order to find out optimum culture condition for algal growth, the effect of light irradiance and temperature on growth rate, biomass composition and pigment production of Spirulina platensis were studied in axenic batch cultures. Growth kinetics of cultures showed a wide range of temperature tolerance from 20 ºC to 40 ºC. Maximum growth rate, cell production with maximum accumulation of chlorophyll and phycobilliproteins were found at temperature 35 ºC and 2,000 lux light intensity. But with further increase in temperature and light intensity, reduction in growth rate was observed. Carotenoid content was found maximum at 3,500 lux. Improvement in the carotenoid content with increase in light intensity is an adaptive mechanism of cyanobacterium S.platensis for photoprotection, could be a good basis for the exploitation of microalgae as a source of biopigments.

Photodynamic effect of two kinds of phycobiliproteins on human liver cancer cell line SMMC-7721 in vitro / 生物工程学报

We studied the effect of photodynamic therapy with phycobiliproteins on human liver cancer cells in vitro. With 3-(4, 5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (MTT assay), we used two phycobiliproteins, R-phycoerythrin (R-PE) and C-phycocyanin (C-PC) prepared from Porphyra yezoensis, to determine the killing rates and apoptosis rates of human liver cancer cells (SMMC-7721) mediated by laser. When the concentration of R-PE was 120 mg/L, the survival rate of human liver cancer cells was 27% after treated by Argon laser with 100 J/cm2 doses, while the survival rate in the control group (without adding R-PE) was 65%. When the C-PC concentration was 120 mg/L, the survival cell rate was 47% after treated by He-Ne laser with 35 J/cm2 dose, while the survival rate in the control group (without adding C-PC) was 70%. After handled only with these two kinds of phycobiliproteins for 72 h, the growth of cancer cells presented significant inhibition. The maximal inhibition rates reached up to 31% with R-PE (120 mg/L concentration) and 27% with C-PC (250 mg/L concentration) respectively. After irradiated by laser for 8 h, the maximal cell apoptosis rates were 31.54% with R-PE and 32.54% with C-PC, respectively. It indicated that R-PE and C-PC extracted from Porphyra yezoensis could develop to new photosensitizers for cancer photodynamic therapy.