The time when plant biostimulants were considered as “snake oil” is erstwhile and the skepticism regarding their agricultural benefits has significantly faded, as solid scientific evidences of their positive effects are continuously provided. Currently plant biostimulants are considered as a full-fledged class of agri-inputs and highly attractive business opportunity for major actors of the agroindustry. As the dominant category of the biostimulant segment, seaweed extracts were key in this growing renown. They are widely known as substances with the function of mitigating abiotic stress and enhancing plant productivity. Seaweed extracts are derived from the extraction of several macroalgae species, which depending on the extraction methodology lead to the production of complex mixtures of biologically active compounds. Consequently, plant responses are often inconsistent, and precisely deciphering the involved mechanism of action remains highly intricate. Recently, scientists all over the world have been interested to exploring hidden mechanism of action of these resources through the employment of multidisciplinary and high-throughput approaches, combining plant physiology, molecular biology, agronomy, and multi-omics techniques. The aim of this review is to provide fresh insights into the concept of seaweed extract (SE), through addressing the subject in newfangled standpoints based on current scientific knowledge, and taking into consideration both academic and industrial claims in concomitance with market’s requirements. The crucial extraction process as well as the effect of such products on nutrient uptake and their role in abiotic and biotic stress tolerance are scrutinized with emphasizing the involved mechanisms at the metabolic and genetic level. Additionally, some often overlooked and indirect effects of seaweed extracts, such as their influence on plant microbiome are discussed. Finally, the plausible impact of the recently approved plant biostimulant regulation on seaweed extract industry is addressed.

Accumulation of high concentrations of heavy metals in environments can cause many human health risks and serious ecological problems. Nowadays, bioremediation using microorganisms is receiving much attention due to their good performance. The aim of this work is to investigate heavy metals resistance and bioaccumulation potential of actinobacteria strains isolated from some abandoned mining areas. Analysis of mining residues revealed that high concentration of zinc “Zn” was recorded in Sidi Bouatman, Arbar, and Bir Nhass mining residues. The highest concentration of lead “Pb” was found in Sidi Bouatman. Copper “Cu,” cadmium “Cd,” and chromium “Cr” were found with moderate and low concentrations. The resistance of 59 isolated actinobacteria to the five heavy metals was also determined. Using molecular identification 16S rRNA, these 27 isolates were found to belong to Streptomyces and Amycolatopsis genera. The results showed different levels of heavy metal resistance; the minimum inhibitory concentration (MIC) recorded was 0.55 for Pb, 0.15 for Cr, and 0.10 mg·mL⁻¹ for both Zn and Cu. Chemical precipitation assay of heavy metals using hydrogen sulfide technic (H2S) revealed that only 27 isolates have a strong ability to accumulate Pb (up to 600 mg of Pb per g of biomass for Streptomyces sp. BN3).

Intensive care units (ICUs) are considered epicenters of antibiotic resistance. The aim of this study is to determine clinical risk factors, epidemiology and the causative agents of multi-drug resistant bacteria in the ICU of the University Hospital in Marrakesh-Morocco. A one year case control study was carried out in our 10-bed clinical and surgical ICU from March 2015 to March 2016. The epidemiological surveillance was done by collecting data in the medical records with the help of a questionnaire. The antibiotic susceptibility testing was used following the recommendations of the Antibiogram Committee of the French Society of Microbiology and the European Committee for Antimicrobial Susceptibility Testing, 2015. Among the 479 admitted patients, 305 bacteria were isolated and identified as Acinetobacter baumannii (31%), Enterobactereacae species (30%), and Staphylococcus (24%), P. aeruginosa (10%) and other bacterial strains (5%). The rate of MDR bacteria acquisition was 41% (124/305) with domination of A. baumannii resistant to imipenem (70%) and followed by Extended Spectrum β-lactamases producing Enterobacteriaceae, P. aeruginosa resistant to Ceftazidime, and Methicillin-resistant S. aureus (18%, 7%, and 5% respectively). The distribution of the common nosocomial infections were dominated by pneumonia, bacteremia, and catheter-related blood stream infections (39%, 29%, and 17%) respectively. Multivariate analysis identified lack of patient isolation precautions (OR: 7.500), use of quadri or triple therapy (OR: 5.596; OR: 5.175), and mechanical ventilation (OR: 4.926), as the most significant clinical and epidemiological factors associated with acquisition of MDR bacteria. The attributable mortality, in this ICU, of patients with MDR bacteria, is about 12%. The incidence of MDR was higher compared with that of developed countries. The implementation of standard infection control protocols, active surveillance of MDR and generation of data on etiological agents and their antimicrobial susceptibility patterns are urgently needed in our hospital.

The present study investigates the effect of Ulva lactuca extract as seed-priming agent for tomato plants under optimal and salinity stress conditions. The aims of this experiment were to assess the effect of seed priming using Ulva lactuca extract in alleviating the salinity stress tomato plants were subjected to, and to find out the possible mechanism of actions behind such a positive effect via means of fractionation of the crude extract and characterization. Salinity application decreased the plant biomass and altered different physiological traits of tomato. However, the application of Ulva lactuca methanol extract (ME) and its fractions (residual fraction (RF), chloroform fraction (CF), butanol fraction (BF), and hexane fraction (HF)) at 1 mg·mL⁻¹ as seed priming substances attenuated the negative effects of salinity on tomato seedlings. Under salinity stress conditions, RF application increased the tomato fresh weight; while ME, RF, and HF treatments significantly decreased the hydrogen peroxide (H₂O₂) concentration and antioxidant activity in tomato plants. The biochemical analyses of Ulva lactuca extract and fractions showed that the RF recorded the highest concentration of glycine betaine, while the ME was the part with the highest concentrations of total phenols and soluble sugars. This suggests that these compounds might play a key role in the mechanism by which seaweed extracts mitigate salinity stress on plants.

Zaitra, Thymus satureioides, is an aromatic plant with a long history of use in traditional medicine. In this study, we assessed the mineral composition, nutritional value, phytocontents, and dermatological properties of the aerial parts of T. satureioides. The plant contained high contents of calcium and iron, moderate levels of magnesium, manganese, and zinc, and low contents of total nitrogen, total phosphorus, total potassium, and copper. It is rich in several amino acids, including asparagine, 4-hydroxyproline, isoleucine, and leucine, and the essential amino acids account for 60.8%. The extract contains considerable amounts of polyphenols and flavonoids (TPC = 118.17 mg GAE/g extract and TFC = 32.32 mg quercetin/g extract). It also comprises 46 secondary metabolites, identified through LC-MS/MS analysis, belonging to phenolic acids, chalcones, and flavonoids. The extract elicited pronounced antioxidant activities, inhibited the growth of P. aeruginosa (MIC = 50 mg/mL), and reduced biofilm formation by up to 35.13% using the ¼ sub-MIC of 12.5 mg/mL. Moreover, bacterial extracellular proteins and exopolysaccharides were diminished by 46.15% and 69.04%, respectively. Likewise, the swimming of the bacterium was impaired (56.94% decrease) in the presence of the extract. In silico, skin permeability and sensitization effects revealed that out of the 46 identified compounds, 33 were predicted to be exempt from any skin sensitivity risk (Human Sensitizer Score ≤ 0.5), while extensive skin permeabilities were observed (Log K_p = −3.35–−11.98 cm/s). This study provides scientific evidence about the pronounced activities of T. satureioides, supports its traditional uses, and promotes its utilization in the development of new drugs, food supplements, and dermatological agents.