Inhibition of growth and mycotoxins formation in moulds by marine algae Cystoseira tamariscifolia

Different extracts from marine algae (Cystoseira tamaricifolia) were tested for their antimicrobial activities. These extracts were examined for their activities on growth of moulds and yeasts and mycotoxines formation by moulds. The Minimal Inhibitory Concentration (MIC) was determined in every case in terms of dilutions. A total inhibition (100%) was obtained with the ethanolic crude extract on all the fungal species at the concentration of 10%. The aqueous extract showed an activity only on some strains used while no activity was observed on yeasts and moulds for both methanolic and aqueous extract. The other extracts (chloroform, hexane and methanol) had no activity on the microbial growth. Mycotoxins formation in Aspergillus flavus was inhibited by the ethanolic extracts at the concentration of 5%. Key Words: Algae, antimicrobial, minimal inhibitory concentration, moulds. African Journal of Biotechnology Vol.3(1) 2004: 71-7

Effet létal de l’extrait aqueux de l’algue brune marine (Cystoseira tamariscifolia) sur la souris et sur les cellules tumorales du myélome murin

L’espèce Cystoseira tamariscifolia est une algue brune marine qui constitue une biomasse algale importante sur la côte atlantiqueMarocaine. L’une des perspectives de notre étude sur cette algue était savalorisation nutritionnelle en vue d’une exploitation économique comme valeur ajoutée aussi bien en alimentation humaine qu’animale à l’instarde plusieurs algues marines comestibles. Pour cette raison, nous avonsété amené à étudier la toxicité aigue de cette espèce et déterminer sa DL50 qui a été réalisée selon la méthode de Spearman-Karber, eninjectant par voie intra péritonéale à un groupe de 36 souris Swiss albinos, répartis en 6 lots de six souris chacun, une dose de 0.5 mL de l’extrait aqueux de l’algue à une concentration donnée, En parallèle une étude de l’effet cytotoxique de l’algue sur les cellules tumorales du myélome murin P3/X63-Ag8.653 a été réalisée en utilisant l’extrait aqueux de l’algue à différentes concentrations. Les résultats obtenus ont montré un net effet toxique de l’algue sur les souris avec une DL50 738.61±34 μg d’algue /g de poids corporel. Nous avons aussi observé un effet cytotoxique de l’algue sur les cellules myélomateuses proportionnel aux concentrations utilisées.Mots-clés : Algue brune marine, Cystoseiracea, extraction, toxicité,cytotoxicit

Co-occurrence of extreme ozone and heat waves in two cities from Morocco

Temperature is the first meteorological factor to be directly involved in leading ozone (O3) extreme events. Generally, upward temperatures increase the probability of having exceedance in ozone adopted thresholds. In the global climate change context more frequent and/or persistent heat waves and extreme ozone (O3) episodes are likely to occur during in coming decades and a key question is about the coincidence and co-occurrence of these extremes. In this paper, using 7 years of surface temperature and air quality observations over two cities from Morocco (Casablanca and Marrakech) and implementing a percentile thresholding approach, we show that the extremes in temperature and ozone (O3) cluster together in many cases and that the outbreak of ozone events generally match the first or second days of heat waves. This co-occurrence of extreme episodes is highly impacted by humidity and may be overlapping large-scale episodes

Antiviral Activities of Sulfated Polysaccharides Isolated from Sphaerococcus coronopifolius (Rhodophytha, Gigartinales) and Boergeseniella thuyoides (Rhodophyta, Ceramiales)

Water-soluble sulfated polysaccharides isolated from two red algae Sphaerococcus coronopifolius (Gigartinales, Sphaerococcaceae) and Boergeseniella thuyoides (Ceramiales, Rhodomelaceae) collected on the coast of Morocco inhibited in vitro replication of the Human Immunodeficiency Virus (HIV) at 12.5 μg/mL. In addition, polysaccharides were capable of inhibiting the in vitro replication of Herpes simplex virus type 1 (HSV-1) on Vero cells values of EC50 of 4.1 and 17.2 μg/mL, respectively. The adsorption step of HSV-1 to the host cell seems to be the specific target for polysaccharide action. While for HIV-1, these results suggest a direct inhibitory effect on HIV-1 replication by controlling the appearance of the new generations of virus and potential virucidal effect. The polysaccharides from S. coronopifolius (PSC) and B. thuyoides (PBT) were composed of galactose, 3,6-anhydrogalactose, uronics acids, sulfate in ratios of 33.1, 11.0, 7.7 and 24.0% (w/w) and 25.4, 16.0, 3.2, 7.6% (w/w), respectively

Concurrent Heat Waves and Extreme Ozone (O3) Episodes: Combined Atmospheric Patterns and Impact on Human Health

More recurrent heat waves and extreme ozone (O3) episodes are likely to occur during the next decades and a key question is about the concurrence of those hazards, the atmospheric patterns behind their appearance, and their joint effect on human health. In this work, we use surface maximum temperature and O3 observations during extended summers in two cities from Morocco: Casablanca and Marrakech, between 2010 and 2019. We assess the connection between these data and climate indices (North Atlantic Oscillation (NAO), Mediterranean Oscillation (MO), and Saharan Oscillation (SaO)). We then identify concurrent heat waves and O3 episodes, the weather type behind this concurrence, and the combined health risks. Our findings show that the concurrence of heat waves and O3 episodes depends both on the specific city and the large-scale atmospheric circulation. The likely identified synoptic pattern is when the country is under the combined influence of an anticyclonic area in the north and the Saharan trough extending the depression centered in the south. This pattern generates a warm flow and may foster photochemical pollution. Our study is the first step toward the establishment of an alert system. It will help to provide recommendations for coping with concurrent heat waves and air pollution episodes