Elemental composition and metal pollution in Egyptian Red Sea mangrove sediments: Characterization and origin.

The present work was conducted to characterize the mangrove sediments along the Egyptian Red Sea in terms of elemental composition and to assess the extent of pollution and its sources. A total of 26 samples of mangrove sediments were collected from three different areas: Sharm El Madfea, Sowmaa Mangrove and Abu Fasi. The samples were analyzed using the inductively coupled plasma - mass spectrometry ICP-MS and atomic-emission spectrometry ICP-AES. Mass fractions of a total of 58 major and trace elements were determined in the mangrove samples. Univariate and multivariate statistical analyses were performed to determine the origin of trace and major elements in the mangrove sediments. The normalized values show that the elements above the background can be indicated in descending order as follows: P > Cd > Sr > Ca > U > Se > As > Sn > Cu > Sb > Pb > Mo > Ag. Several pollution indices were also calculated. Principal component analysis revealed three clusters of the studied sediment samples. The analysis of the ratio indicators shows that the origin of the sediments mostly falls near continental island arcs (CIA). The pollution indices show remarkable pollution levels and enriched elements. The data obtained can serve as baseline data for the sediments of the mangrove environment and can be used to study possible changes in the future.

The genus Turbinaria: chemical and pharmacological diversity.

The Genus Turbinaria is still chemically and pharmacologically underexplored. These brown algae belong to the family Sargassaceae. Therapeutic potentials of pure compounds isolated from the Genus Turbinaria are extraordinarily promising as antiproliferative, antipyretic, anti-inflammatory immunostimulatory, anti-diabetic, anti-obesity, antiviral, antimicrobial, cardioprotective, hepatoprotective and hypolipidemic. Those activities are represented by diverse classes of compounds including sterols, amino acids, fatty acids, alcohols, halocarbons, hydrocarbons, carbohydrates, esters and cyclic tetrapyrrole compounds. This review focuses on the Genus Turbinaria during the period 1972 to 2019.

Pharmacological and natural products diversity of the brown algae genus Sargassum.

Sargassum (F. Sargassaceae) is an important seaweed excessively distributed in tropical and subtropical regions. Different species of Sargassum have folk applications in human nutrition and are considered a rich source of vitamins, carotenoids, proteins, and minerals. Many bioactive compounds chemically classified as terpenoids, sterols, sulfated polysaccharides, polyphenols, sargaquinoic acids, sargachromenol, and pheophytin were isolated from different Sargassum species. These isolated compounds and/or extracts exhibit diverse biological activities, including analgesic, anti-inflammatory, antioxidant, neuroprotective, anti-microbial, anti-tumor, fibrinolytic, immune-modulatory, anti-coagulant, hepatoprotective, and anti-viral activities. This review covers the literature from 1974 to 2020 on the genus Sargassum, and reveal the active components together with their biological activities according to their structure to create a base for additional studies on the clinical applications of Sargassum.

Actinomycetes from the Red Sea Sponge Coscinoderma mathewsi: Isolation, Diversity, and Potential for Bioactive Compounds Discovery.

The diversity of actinomycetes associated with the marine sponge Coscinoderma mathewsi collected from Hurghada (Egypt) was studied. Twenty-three actinomycetes were separated and identified based on the 16S rDNA gene sequence analysis. Out of them, three isolates were classified as novel species of the genera Micromonospora, Nocardia, and Gordonia. Genome sequencing of actinomycete strains has revealed many silent biosynthetic gene clusters and has shown their exceptional capacity for the production of secondary metabolites, not observed under classical cultivation conditions. Therefore, the effect of mycolic-acid-containing bacteria or mycolic acid on the biosynthesis of cryptic natural products was investigated. Sponge-derived actinomycete Micromonospora sp. UA17 was co-cultured using liquid fermentation with two mycolic acid-containing actinomycetes (Gordonia sp. UA19 and Nocardia sp. UA 23), or supplemented with pure mycolic acid. LC-HRESIMS data were analyzed to compare natural production across all crude extracts. Micromonospora sp. UA17 was rich with isotetracenone, indolocarbazole, and anthracycline analogs. Some co-culture extracts showed metabolites such as a chlorocardicin, neocopiamycin A, and chicamycin B that were not found in the respective monocultures, suggesting a mycolic acid effect on the induction of cryptic natural product biosynthetic pathways. The antibacterial, antifungal, and antiparasitic activities for the different cultures extracts were also tested.

Distribution patterns of natural radionuclides and rare earth elements in marine sediments from the Red Sea, Egypt.

The present study was conducted to study the compositional trends of rare earth elements (REEs), Th, and U in marine sediment samples in terms of distribution patterns, anomalies, and indicator ratios. For this purpose, a total of 32 marine sediment samples were collected from 12 coastal areas of the Egyptian Red Sea and analyzed using instrumental neutron activation (INAA) and inductively coupled plasma mass spectrometry (ICP-MS) analytical techniques. The analyses investigated 14 REEs, Th, and U. The results revealed that the contents of REE, light REE (LREE), and heavy REE (HREE) are 47.6, 38.7, and 8.3 mg/kg, respectively, whereas the concentration of Th and U is determined as 2.15 and 2.23 mg/kg, respectively. Indicator ratios were calculated, and inter-correlation elements with Th and U were constructed. Multivariate statistics were implemented on the data and GIS technology to construct the distribution patterns of REE, Th, and U along the Egyptian coast of the Red Sea. The obtained results were compared with the corresponding values published in literature to show a good matching. There is a significant enrichment of LREE relative to HREE, a reduced ratio of Th/U, a weak positive anomaly of Eu/Eu*, and a slight positive Ce anomaly is noticed. Among the 12 studied areas, one area, Sharm El-Bahari, located in the middle of the coast, shows peak values of REE, Th, and U relative to the other areas. However, it still shows a good agreement with the results published in the literature.

Assessment of anthropogenic and geogenic impacts on marine sediments along the coastal areas of Egyptian Red Sea.

The present study was conducted to assess the possible impacts of human activities and naturally occurring on the marine sediments, to test for anomalous enrichments in metals. A total of 32 marine sediments samples collected from 12 coastal areas of the Egyptian Red Sea analyzed using different analytical techniques. The analysis explored 43 elements for the marine sediments. Principal component analysis and multivariate statistics were implemented on the data. The extent of pollution was quantified for selected 6 pollutants using the geoaccumulation indices (Igeo), enrichment factor (EF), metal pollution index (MPI), contamination factor (Cf), and degree of contamination factor (Cd). The associated risk using potential ecological risk factor (PER), and risk index (RI) was calculated. The data was interpolated using ArcGIS technology to construct the spatial distribution maps of the selected 6 pollutants along the coastal areas of the Egyptian Red Sea. The data was normalized and the peak values were observed for Ca (13.6%) >Na (1.9%) > Mg (1.6%) >Br (41.1 ppm). The obtained findings were compared with other local and regional data shows that the metal enrichment in studied areas is in line and anomalous enrichments in metals were not evidenced. Even though out of 12 studied areas 2 areas viz., Sharam El-Bahari in the middle of the coast and downwards to the southern Marsa Hemira area found to have peak values of metals, however still show a good agreement with results with other data. Moderate enriched sediments with Cr were noticed. It could be stated that comparison of the gained data from this study with others clearly indicates that nearly the metal concentrations were in the natural unpolluted sediments range.

Environmental and radio-ecological studies on shallow marine sediments from harbour areas along the Red Sea coast of Egypt for identification of anthropogenic impacts.

Analysis of marine sediments of the studied localities provides investigators with data to characterise the composition of these sediments allowing for the identification of particular pollution sources. A study of texture, geochemistry, X-ray diffraction and natural radionuclide content of shallow marine sediments from Quseir harbour, Safaga harbour and El-Esh area in the Red Sea coast of Egypt was conducted for the purpose of assessing the possible influence of human activities on the composition of the sediments. The activity concentrations of the naturally occurring radionuclides (226)Ra, (232)Th and (40)K were measured by using γ-ray spectrometry. The mean activity concentrations of (226)Ra, (232)Th and (40)K in all areas studied were found to be 71±6, 66±5 and 92±7 Bq kg(-1) for (226)Ra, 83±5, 71±7 and 162±23 Bq kg(-1) for (232)Th and 513±10, 493±20 and 681±28 Bq kg(-1) for (40)K, respectively. The results of the study presented were compared with corresponding results obtained in other coastal and aquatic environments in the Red Sea.