Characterization of a Dialdehyde Chitosan Generated by Periodate Oxidation

This article reports the oxidation of Chitosan by using periodate and the characterization of the dialdehyde chitosan (DAC) generated by the reaction. Oxidised chitosan were further characterised by FTIR analysis, 1HNMR and TGA. The morphological analyses of oxidized chitosan by SEM confirmed the non change of elongated and fibrous network of chitosan. FTIR and TGA show no significant change on chemical structure and thermal properties successively. 1H NMR study confirmed the presence of imines generated by the reaction between dialdehyde chitosan and amino groups of chitosan (spontaneous assembling)

Learning of chemistry of solution with help of computer simulation

Le présent article rend compte d'une expérimentation utilisant des simulations informatiques de titrages acide-base dans des situations didactiques d'apprentissage basées sur l'investigation et la participation de l'apprenant dans la construction de son savoir. Deux approches dans l'utilisation des simulations de titrages pH-métriques à l'aide du logiciel «SIMULTI2» sont mises en place et évaluées avec un groupe d'enseignants en formation continue et un groupe d'élèves-professeurs en formation initiale. On montre que les simulations informatiques créent un contexte pédagogique favorisant l'apprentissage par la découverte ou l'exploration basée sur les conflits cognitifs

Elaboration and characterization of a new activated carbon obtained from oregano residue: Application in environmental field

This study focuses on the valorization of extraction residues of medicinal plants which represent approximately 80% of the gross weight of the plant. In this context we proceeded to the transformation of “marc oregano” to a material adsorbent type activated carbon. The oregano marc, obtained after extraction of essential oils and organic compounds, has undergone a chemical activation using the phosphoric acid 85% (H3PO4). It is well known as precursors of lignocellulosic activating agent, allows the development of a large porosity in the activated material. The activated product has subsequently underwent heat treatment in the temperature range from 200 to 350 °C. The optimum temperature for development was set at 300 °C. The results obtained showed that the adsorbent material O300 has developed the interesting textural properties. It is an adsorbent material like activated carbon, which presents, according to the BET method, a specific surface of 1200 m2·g−1 (specific surface area of commercial activated carbon is of about 905 m2·g−1). The application of adsorbent material developed O300 in microbial decontamination of urban waste water, has revealed its effectiveness and its important adsorptive properties against pathogens pollutants from wastewater

Development of A New Biosorbent Based on The Extract Residue of Marine Alga Sargassum Vulgare: Application in Biosorption of Volatile Organic Compounds

The objective of this study is the valorization of a sub-product of marine alga it is the extract residue of the marine alga Sargassum vulgare, which represents more than 80% of the weight of the raw material. It is a natural residue thatnbsp wenbsp couldnbsp turnnbsp into nbspbiosorbentnbsp undernbsp thenbsp effectnbsp ofnbsp chemicalnbsp activationnbsp withnbsp phosphoricnbsp acidnbsp whichnbsp allowsnbsp the development of a large pore in the activated material.nbsp To optimize the conditions for elaboration of our biosorbent, experimental design was applied to reduce the number of experiment trials needed to evaluatenbsp some parameters (percentage of phosphoric acid, temperature and time of activation) and theirnbsp effects on the responses (capacity of biosorption of methylene blue, yield biosorbent).nbsp The product obtained under the optimal conditions has good textural and structural properties and development of surface functions.nbsp The application of optimized biosorbent in the treatment of gaseous effluents, has revealed its efficiency and significant biosorption properties towards some volatile organic compounds i .e.nbsp the toluene, the cyclohexane and the ethylbenzene

Extraction and Recovery of Bioactive Metabolites from Marine Spongeand#8220;Ircinia spinulosaand#8221;

Oceans cover more than 75% of our planet. In some ecosystems, such as coral reefs, experts believe that biodiversity is greater than that of tropical forests. Morocco, with its double facade Atlantic and Mediterranean, long of more than 3500 km, is a country deeply influenced by the sea, which implies the existence of thousands of marine species by reports in other countries. Currently, marine organisms are a very important source of new molecules in pharmacology and thus in the development of new bioactive products. Sponges, in particular, given their very primitive origin and persistence during evolution, have developed a chemical defense system. This study aims the biological valorization of crude extract from a marine sponge collected in Atlantic coastal El Jadida: Ircinia spinulosa. The chemical study of Ircinia spinulosa, marine sponge was realized for the first time in Morocco, and revealed that this sponge contains different levels of primary and secondary metabolites. Analysis of fatty acids in the lipid extract of Ircinia spinulosa is performed by gas chromatography coupled with mass spectrometry (GC-MS) was used to determine the predominance of acid Palmitic. This molecular diversity of sponges has a large deposit of biological and biomedical potential. What pushed us to continue the research to isolate new and original molecules

Extraction and Recovery of Bioactive Metabolites from Marine Spongeand#8220;Ircinia spinulosaand#8221;

Oceans cover more than 75% of our planet. In some ecosystems, such as coral reefs, experts believe that biodiversity is greater than that of tropical forests. Morocco, with its double facade Atlantic and Mediterranean, long of more than 3500 km, is a country deeply influenced by the sea, which implies the existence of thousands of marine species by reports in other countries. Currently, marine organisms are a very important source of new molecules in pharmacology and thus in the development of new bioactive products. Sponges, in particular, given their very primitive origin and persistence during evolution, have developed a chemical defense system. This study aims the biological valorization of crude extract from a marine sponge collected in Atlantic coastal El Jadida: Ircinia spinulosa. The chemical study of Ircinia spinulosa, marine sponge was realized for the first time in Morocco, and revealed that this sponge contains different levels of primary and secondary metabolites. Analysis of fatty acids in the lipid extract of Ircinia spinulosa is performed by gas chromatography coupled with mass spectrometry (GC-MS) was used to determine the predominance of acid Palmitic. This molecular diversity of sponges has a large deposit of biological and biomedical potential. What pushed us to continue the research to isolate new and original molecules

Bioprospecção de macroalgas marinhas e plantas aquáticas para o controle da antracnose do feijoeiro Bioprospecting of marine seaweeds and aquatic plants for controlling the bean anthracnose

O objetivo deste trabalho foi testar o efeito local, residual e sistêmico, de extratos de 17 espécies de macroalgas marinhas e de duas plantas aquáticas, sobre a antracnose do feijoeiro. Para tanto, os espécimes foram coletados, identificados, secos em estufa (50ºC/ 48 h), moídos e seus compostos extraídos com etanol. Plantas de feijoeiro (Phaseolus vulgaris cv. Uirapuru) foram cultivadas em vasos, em casa-de-vegetação. Os 19 extratos foram subdivididos e testados em duas etapas de seleção e comparação independentes, utilizando-se o delineamento inteiramente ao acaso, com cinco repetições (vasos com três plantas). As plantas foram pulverizadas com extratos na concentração de 50 mg de peso seco/mL quando apresentavam o primeiro trifólio expandido. Para verificar o efeito local, as plantas foram inoculadas com uma suspensão de 1,2 x 10(6) conídios/mL 4 horas após o tratamento, enquanto que para o estudo do efeito residual e sistêmico, as plantas foram inoculadas 7 dias após o tratamento. A severidade da antracnose foi avaliada 7 dias após a inoculação (dai) na planta inteira e no trifólio não tratado (efeito sistêmico), utilizando-se uma escala de 1 a 9. As algas e plantas que reduziram significativamente a severidade da doença foram comparadas em experimento avaliado aos 7 e aos 12 dai. O extrato de Bryothamnion seaforthii apresentou efeito local, reduzindo em 35% a severidade da antracnose, enquanto o extrato de Ulva fasciata demonstrou efeito residual com redução de 22% na doença aos 12 dai. Somente os extratos de Lemna sp. e U. fasciata reduziram sistemicamente a severidade de doença aos 7 dai na ordem de 55 e 44%, respectivamente, em relação à testemunha. O possível modo de ação desses extratos é discutido.<br>The goal of this work was to test the local, residual as well as systemic effect of extracts from 17 marine seaweeds and two aquatic plant species against the bean anthracnose. For that, specimens were collected, identified, dried into an oven at 50ºC for 48 h, ground to powder and their compounds extracted with ethanol. Bean plants (Phaseolus vulgaris cv. Uirapuru) were grown in pots under greenhouse conditions. The 19 extracts were shared into two independent groups for screening and comparison in a completely randomized design, with five replications (pot with 3 plants). Plants at the first trifoliolate leaf stage were sprayed with extracts at concentration of 50 mg dry weight/mL. To assess the local effect, plants were inoculated with a suspension of 1.2 x 10(6) conidia/mL 4 h after the treatment, whereas to study the residual and systemic effects, inoculation was performed after 7 days. Disease severity was evaluated 7 days after inoculation (dai) on either whole plants or the non-treated leaf (systemic effect), using a scale from 1 to 9. Seaweeds and plants which significantly reduced anthracnose were compared in a follow-up experiment evaluated at both 7 and 12 dai. The extract of Bryothamnion seaforthii revealed local effect reducing the anthracnose severity by 35%. Ulva fasciata extract showed residual effect reducing the anthracnose at 12 dai by 22%. Compared to control, only extracts of Lemna sp. and U. fasciata systemically reduced the disease severity at 7 dai by 55 e 44%, respectively. The possible mode of action of these extracts is discussed

Antimicrobial and antioxidant activities with acute toxicity, cytotoxicity and mutagenicity of Cystoseira compressa (Esper) Gerloff & Nizamuddin from the coast of Urla (Izmir, Turkey)

WOS: 000347948200014PubMed ID: 24292649The aim of the study was to evaluate the biological activities with toxic properties of the methanol, hexane, and chloroform extracts of Cystoseira compressa (Esper) Gerloff & Nizamuddin from the Coast of Urla in the Aegean Sea. The extracts of C. compressa were tested for their antimicrobial and antioxidant activities in this study. Cytotoxic and mutagenic potentials of the extracts were also evaluated using cell culture and mutagenicity assays. Hexane extract was found to have higher total flavonoid and phenolic contents than the other extracts and exerted higher antioxidant activity than other extracts. All extracts exhibited moderate antimicrobial activity against tested microorganisms (minimum inhibitory concentration ranges are 32-256 mu g/mL). The results indicated that the extracts had no significant cytotoxic activity against human hepatocellular carcinoma Hep 3B cell line in all treated concentrations (5-50 mu g/mL) and did not show mutagenicity in the Ames test. Lethality was not observed among mice treated with oral doses of the extracts. In conclusion, results of investigations indicate that brown alga C. compressa is a natural source of antioxidant. It has moderate antimicrobial activities with no toxicity