Imen Hamed

Marine Bioactive Compounds and Their Health Benefits: A Review

The significance of marine creatures as a source of unique bioactive compounds is expanding. Marine organisms constitue nearly half of the wordwide biodiversity; thus, oceans and sea present a vast resource for new substances and it is considered the largest remaining reservoir of beneficial natural molecules that maight be used as functional constituents in the food sector. This review is an update to the information about recent functional seafood compounds (proteins, peptides, amino acids, fatty acids, sterols, polysaccharides, oligosaccharides, phenolic compounds, photosynthetic pigments, vitamins, and minerals) focusing on their potential use and health benefits.

The Evolution and Versatility of Microalgal Biotechnology: A Review

Microalgal biotechnology has emerged due to the health-promoting properties of microalgae related to their bioactive compounds and the great diversity of products that can be developed from algal biomass. Microalgal biomasses have been produced industrially for applications in different fields such as food, pharmaceutical, nutraceutical, cosmetic, and animal feed industries. They can be cultivated either in open systems or in closed systems (photobioreactors). Another important area is the use of microalgal biomass for energy production. It has become obvious that petroleum-derived fuels are unsustainable, due to depleting world reserves and greenhouse gas emissions. Microalgae can provide several different types of renewable biofuels. These include methane produced by anaerobic digestion of the algal biomass, biodiesel derived from trans-esterification of microalgal lipids, bioethanol produced from carbohydrate fermentations, and photobiologically produced biohydrogen. The idea of using microalgae as a source of fuel is not new. However, it is now being taken seriously because of increases in petroleum prices and, more significantly, the increasing concern about global warming as associated with burning fossil fuels. This review offers an update on information about microalgae, specifically emphasizing their biotechnological importance.

The function of probiotics on the treatment of ventilator-associated pneumonia (VAP): facts and gaps

Abstract Probiotics have been used for centuries in making fermented dairy products. The health benefits related to probiotics consumption are well recognized and they are generally regarded as safe (GRAS). Their therapeutic effects are due to the production of a variety of antimicrobial compounds, such as short‐chain fatty acids, organic acids (such as lactic, acetic, formic, propionic and butyric acids), ethanol, hydrogen peroxide and bacteriocins. Ventilator‐associated pneumonia (VAP) is a nosocomial infection associated with high mortality in intensive care units. VAP can result from endotracheal intubation and mechanical ventilation. These interventions increase the risk of infection as patients lose the natural barrier between the oropharynx and the trachea, which in turn facilitates the entry of pathogens through the aspiration of oropharyngeal secretions containing bacteria into the lung. In order to prevent this, probiotics have been used extensively against VAP. This review is an update containing information extracted from recent studies on the use of probiotics to treat VAP. In addition, probiotic safety, the therapeutic properties of probiotics, the probiotic strains used and the action of the probiotics mechanism are reviewed. Furthermore, the therapeutic effects of probiotic treatment procedures for VAP are compared to those of antibiotics. Finally, the influences of bacteriocin on the growth of human pathogens, and the side‐effects and limitations of using probiotics for the treatment of VAP are addressed.

Marine-Based Toxins and Their Health Risk

Abstract Marine toxins, which are poisonous when ingested, are a threat to human health. Toxins, such as tetrodotoxin, palytoxin, nodularin, and domoic acid, may be produced in large amounts by marine microorganisms, including phytoplankton (dinoflagellates, cyanobacteria, and diatoms) and bacteria. Algal and bacterial toxins are ingested by various species, such as filter-feeding shellfish, zooplankton, and herbivorous fishes. They are accumulated in those organisms and transferred to higher trophic levels along food chains. Diagnosis is made following apparition of various symptoms (abdominal cramps, vomiting, and gastrointestinal disorders), and a history of eating seafood in the preceding 24h. Tetrodotoxin (TTX) is a potent neurotoxin found in marine species especially puffer fish and other terrestrial animals. TTX binds to voltage gated sodium channels that block the flow of sodium ions through the channels. This could result in respiratory and heart failure and could then lead to death. In addition, consumption of seafood contaminated by toxins results in different seafood poisoning syndromes, including paralytic shellfish poisoning, neurotoxic shellfish poisoning, amnesic shellfish poisoning, diarrheic shellfish poisoning, ciguatera fish poisoning, and azaspiracid shellfish poisoning. These toxins are tasteless, odorless, heat and acid stable. Thus, if seafood products are contaminated, intoxications cannot be eliminated by processing techniques, such as canning; marinating; irradiation; and salting. To prevent seafood poisoning, some steps have to be taken, including extensive controlling of toxins content in seafood and banning of the harvesting when toxic algal bloom go beyond a certain level in marine ecosystems.