Intracellular increase of glutamate in neuroblatoma cells induced by polar substances of Galaxaura marginata (Rhodophyta, Nemaliales) / Aumento do glutamato intracelular induzido por substâncias polares de Galaxaura marginata (Rhodophyta, Nemaliales) em células de neuroblastoma

Four substances purified by HPLC from red seaweed Galaxaura marginata (Ellis & Solander) Lamouroux showed neuroprotective and mitochondria regulatory properties in neuroblastoma NEURO-2A cells line. Under oxidative basal conditions, each substance is capable of modifying the glutamate, glutamine and alanine intracellular concentrations, without to alter the oxidative equilibrium of these cells. These substances, also, produced a biphasic activity in the mitochondrial metabolism, inhibiting, in lower concentrations and stimulating, in higher concentrations the mechanism of cellular 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction, that indicates the mitochondrial activity. These data suggest that the intracellular increase of glutamate can be related to the glutamate/glutamine cycle alterations induced by the blockade of intracellular glutamate transport. Moreover, we suggested that there are substances, exhibiting neuroprotective activity in neuroblastoma cells, protecting them from oxidative stress produced by the inhibition of the glutamate transporters.

Quatro substâncias purificadas da alga vermelha Galaxaura marginata (Ellis & Solander) Lamouroux, mediante HPLC, apresentaram propriedades neuroprotetoras e reguladoras da atividade mitocondrial quando testadas em células de neuroblastomas da cepa NEURO-2. Sob condições oxidativas basais, cada substância é capaz de modificar as concentrações intracelulares de glutamato, glutamina e alanina, sem alterar o equilíbrio oxidativo das células. Essas substâncias também produziram uma atividade bifásica no metabolismo mitocondrial, inibindo em baixas concentrações e estimulando em altas concentrações o mecanismo celular de redução do 3-(4,5-dimetiltiazol-2-il)-2,5-difeniltetrazol brometo (MTT), que indica atividade mitocondrial. Esses dados sugerem que o aumento do glutamato pode estar relacionado com a alteração do ciclo glutamato/glutamina induzido pelo bloqueio do transporte intracelular de glutamato. Além disso, nós sugerimos que essas substâncias exibem atividade neuroprotetora nas células de neuroblastoma, as protegendo do estresse oxidativo, produzido pela inibição dos transportadores de glutamato.

Bioactivity of marine organisms: Part IX--screening of some marine flora from the Indian coasts.

Alcoholic extracts of 48 identified species of marine flora were screened for a wide range of biological activities. Of these, 3 extracts showed diuretic activity while 2 extracts showed hypotensive effect.

Clastogenic effects of dietary supplement--Spirulina alga, and some medicinal plant products from Boswellia serrata, Withania somnifera on mice.

Pretreatment of aqueous extracts of Zyrulina (Spirulina), Aswagandha (Withania) and Nopane (Boswellia) on colchicine induced chromosome damage showed weakness of clastogenic activity in Swiss albino mice. None of the treatments increased significantly the number of chromosome aberrations.

Modelling a binuclear metal binding site in the photosynthetic reaction centre II.

Based on the experimental data and homologous sites in Protein Data Bank (PDB) a model for metal binding sites in D1/D2 heterodimer has been proposed. On searching for tetranuclear and binuclear Mn binding sites in the PDB, a suitable sequence homology in thermolysin and D1 could be observed. From the homology and site-directed mutagenesis data, a model for binuclear Mn-Ca or Mn-Mn has been built and it is extended to a tetranuclear Mn centre.

Mineral acid effect on the trace element determination in lichen certified reference material and algae by inductively coupled plasma atomic emission spectrometry

A study has been made of mineral acid matrix interferences in trace element determinations and methods are described for the multi-element analysis of lichen and algae [biomonitors] using inductively Coupled Plasma Emission Spectrometry [ICP-AES]. Several calibration strategies were compared employing aqueous standards with and without acids using modified ICP instrumental parameters. There was marked depression in analyte signal intensity in all the measurements. It has been shown that signal depressions of up to 32% can be observed under normal operating conditions. The use of acid matrix-matched standards and internal standard for calibrations substantially reduced signal depression problem. The methods gave elemental recovery from 97.7 to 98.8%. The accuracy of the methods was assessed by analysing the certified lichen material from the International Atomic Energy Agency [IAEA]. Accurate results were obtained by using the above calibration strategy with improved precision

Antioxidant activity of the microalga Spirulina maxima

Spirulina maxima, which is used as a food additive, is a microalga rich in protein and other essential nutrients. Spirullina contains phenolic acids, tocopherols and Beta-carotene which are known to exhibit antioxidant properties. The aim of the present study was to evaluate the antioxidant capacity of a Spirulina extract. The antioxidant activity of a methanolic extract of Spirulina was determined in vitro and in vivo. The in vitro antioxidant capacity was tested on a brain homogenate incubated with and without the extract at 37 degrees Celsius. The IC(50) (concentration which causes a 50 per cent reduction of oxidation) of the extract in this system was 0.18 mg/ml. The in vivo antioxidant capacity was evaluated in plasma and liver of animals recceiving a daily dose of 5 mg for 2 and 7 weeks Plasma antioxidant capacity was measured in brain homogenate incubated for 1 h at 37 degrees Celsius. The production of oxidized compounds in liver after 2 h of incubation at 37 degrees Celsius was measured in terms of thiobarbituric acid reactant substances (TBARS) in control and experimental groups. Upon treatment, the antioxidant capacity of plasma was 71 per cent for the experimental group and 54 per cent for the control group. Data from liver spontaneous peroxidation studies were not significantly different between groups. The amounts of phenolic acids, alpha-tocopherol and Beta-carotene were determined in Spirulina extracts. The results obtained indicate that Spirulina provides some antioxidant protection for both in vitro and in vitro and vivo systems.

Open-door mass production, chemical composition and biological evaluation of different algal species

Production of biomass from algae as a source of protein is running in Egypt since few years on scale of 24 m2. A clean medium using commercial foliar fertilizer as nutrient solution was used. For the mass production of algae the following species were used; Chlorella vulgaris, Scenedesmus obliquus, Coelastrum sphaericum, Oscillatoria amphibia and Spirulina platensis. Average yields were 15, 15, 19, 18 and 22 g/m2 for the above-mentioned species, respectively. The average chemical composition of the green algae species showed 50.1-55.1% crude protein, and for the last two blue green algae species was 62.2-63.5%. Protein efficiency ratio [PER] and digestibility were found to be within the range 1.9-2.3 and 71-78%, respectively. The product was used as supplement to chicken feed. Small scale trials to cultivate green on waste water of sugar industry as well as poultry manure extract [PME] showed promising and comparable results to the clean culture

Marine natural products in Brazil. Part 1. Isolation and sctruture determination

Chemistry of marine natural products started in Brazil 35 years ago. Studies focus on invertebrates (Echinoderms, Coelenterates, Porifera, Tunicates and Mollusks) and brown algae, and to a lesser extend green algae, red algae and sharks. Some sixty different organisms have yielded over 110 identified metabolites. So far, steroids, diterpenes and sesquiterpenes have received almost all the attention. Among other metabolites, higher terpenes, long-chain lipids, tyrosine-derived dibromo compounds, two purines and one pyridine alkaloid have been described. This review reports on the history of marine natural product chemistry in Brazil and on the isolation and structure determination of these metabolites. Some unpublished results are presented.

Bioactivity of marine organisms: Part VIII--Screening of some marine flora of western coast of India.

Methanolic extracts of 31 botanically identified species of marine flora, collected from Gujarat Coast, have been screened for a wide range of biological activities. Of these, 3 extracts showed anti-implantation, 2 had antiviral, 2 showed hypotensive, 1 had anti-inflammatory while 12 extracts showed diuretic activities. The antiviral activity; against EMCV, was confirmed in one alga. The active principles and results of these studies are reported.

Strategies for the structure determination of parasite glycoconjugates using fast atom bombardment mass spectrometry

Fast atom bombardment mass spectrometry (FAB MS) is a sensitive and powerful technique for the analysis of thermally labile and involatile materials. In this paper we describe the application of the method to the characterization of oligosaccharides isolated from the cell surface glycoconjugates of parasitic protozoa. The spectra typically contain both molecular ions, which define the monosaccharide composition, and fragment ions which are related to the structure of the intact molecules. The use of additional techniques such as chemical derivatization and colisional activation enhances fragmentation and simplifies interpretation of the data, enabling the determination of residue sequence, the positions of branch points, and the location of noncarbohydrate substituents. We have applied these techniques to the characterization of phosphoinositol oligosaccharides from members of the Trypanosoma family, including Leptomonas smueli, Endotrypanum schaudinni and Leishmania adleri. Although it is not usually possible to determine the complete structure of oligosaccharide by mass spectrometric methods alone, the information gained greatly simplifies the interpretation of the results from other techiniques such as nuclear magnetic resonance and methylation analysis.

Producción de agar-agar en Costa Rica a partir de Gracilaria Fortissima / Production of agar-agar in Costa Rica from Gracilaria Fortissima

Se evaluaron comparativamente cinco diferentes métodos de tratamiento previo para la extracción de agar a partir de algas de la especie, Gracilaria Fortissima recogida en Cahuita, provincia de Limón, Costa Rica. Los tratamientos previos utilizados fueron: alcalino a 90-95ºC y a 70-75ºC ácido a 17ºC, combinando alcalino-ácido a 90-95ºC y 80-85ºC y se comparó con la extracción sin tratamiento previo de ácido las algas. El agar obtenido se evaluó con respecto a los siguientes parámetros: rendimiento, temperatura de fusión, temperatura de gelificación, fuerza del gel y apariencia del mismo. El tratamiento combinado alcalino-ácido a 90-95ºC resultó ser el más adecuado para la extracción del agar. Se sugiere extender el estudio hacia otras especies de algas rojas presentes en Cahuita que podrían producir agar de mejor calidad.