Thymus satureioides Coss.: Mineral Composition, Nutritional Value, Phytochemical Profiling, and Dermatological Properties.

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 » 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 Kp = -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.

Screening and Characterization of Streptomyces spp. Isolated from Three Moroccan Ecosystems Producing a Potential Inhibitor of the Drug Efflux Pump AcrAB-TolC.

Traditional antimicrobial antibiotics are increasingly suffering from the emergence of multidrug resistance among pathogenic microorganisms. The antibiotic era is threatened by the ruthless rise of resistance in bacterial infections. A significant role in these resistance profiles is attributed to multidrug efflux pumps. Hence, much effort is being directed towards developing new compounds to overcome this problem. During our screening program of efflux pumps inhibitors (EPI) produced by bioactive Moroccan Actinobacteria, 210 isolates were screened for their antibacterial activities against Escherichia coli strains containing a system of efflux pump AcrAB-TolC, fully functional, and its mutant, inactivated due to the insertion of transposon Tn903 in AcrAB operon, using the method of agar disc diffusion. The results showed that 14 isolates were able to produce EPI as they were active against the wild type strain but not against the mutant in comparison with the synthetic inhibitor L-Phe-L-Arg-ß-naphthylamide (PaßN). We focused on the highest EPI activity produced by four strains (Z332, Z35/G, Z385/b and 136). Taxonomic studies and the 16S rDNA sequence indicated that these strains belonged to the Streptomyces species. This work could contribute to the discovery of a new class of antibacterial agents that could expand the therapeutic arsenal.

Ulva lactuca Extract and Fractions as Seed Priming Agents Mitigate Salinity Stress in Tomato Seedlings.

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.

Moroccan actinobacteria with promising activity against toxic cyanobacteria Microcystis aeruginosa.

In recent decades, harmful cyanobacterial blooms (HCBs) have become a severe hazard for human health mainly in drinking water resources and are responsible for serious ecological disturbances in freshwater ecosystems. The present study aims to explore the potential of actinobacteria isolated from sediment samples collected from Moroccan salt river to control HCBs mainly through Microcystis aeruginosa lysis. In order to investigate the possible anti-cyanobacterial response mechanisms, the antioxidant enzyme activities of M. aeruginosa cells were analysed. Anti-cyanobacterial activity was tested using the agar cylinder method against the toxic cyanobacteria Microcystis aeruginosa. Amongst the twenty-three isolates tested, only one showed promising anti-cyanobacterial activities with inhibition zone (ZI) equal to 22.00 mm, minimum inhibitory concentration (MIC) equal to 19.53 mg/L and minimum bactericidal concentration MBC equal to 39.06 mg/L. Phylogenetic analysis of the near-complete 16S rRNA gene sequence indicated that the strain DS1R1 belongs to the genus Streptomyces and has the highest similarity (100%) to Streptomyces sp. Indeed, M. aeruginosa growth, chlorophyll-a and protein content were significantly reduced by Streptomyces sp. DS1R1 extract. Superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) were significantly elevated after treatment with Streptomyces sp. DS1R1 extract. These experimental findings provided insights in the development of a new eco-friendly procedure based on the use of actinobacteria for toxic cyanobacterial bloom bio-control.

Trends in Seaweed Extract Based Biostimulants: Manufacturing Process and Beneficial Effect on Soil-Plant Systems.

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.

The clinical and epidemiological risk factors of infections due to multi-drug resistant bacteria in an adult intensive care unit of University Hospital Center in Marrakesh-Morocco.

BACKGROUND: 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. METHODS: 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. RESULTS: 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 ß-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%. CONCLUSIONS: 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.

Draft Genome Sequence of the Novonestmycin-Producing Strain Streptomyces sp. Z26, Isolated from Potato Rhizosphere in Morocco.

Streptomyces sp. strain Z26 exhibited antifungal activity and turned out to be a producer of the secondary metabolites novonestmycin A and B. The 6.5-Mb draft genome gives insight into the complete secondary metabolite production capacity and builds the basis to find and locate the biosynthetic gene cluster encoding the novonestmycins.

Screening for Non-polyenic Antifungal Produced by Actinobacteria from Moroccan Habitats: Assessment of Antimycin A19 Production by Streptomyces albidoflavus AS25.

Fungal diseases are currently a serious public health problem, due to the limited number of fact-based effective principles, and the emergence of resistant strains to the polyenic antifungals. The aim of this study was to screen, for non-polyenic antifungals production by Actinobacteria, and to validate the screening program by characterizingthe produced compounds.Actinobacteria isolates were tested against four clinic human-pathogenic fungi isolated from Hospital Mohammed V Rabat, Morocco. The production of non-polyenic antifungal metabolites by active isolates was investigated based on the yeast cell specificity as challenging targets, antibacterial activity, activity against resistant Candida tropicalis R2 and Pythium irregular (resistant to polyenes), inhibition of antifungal activity by the addition of exogenous ergosterol, and the UV-visible light spectrophotometric analysis of the active crude extracts.The antifungal compound produced was purified using various chromatographic techniques and the selected producing strain was identified using the polyphasic approach.Among 480 Actinobacteria isolates, 55 showed antifungal activity against all tested clinically derived fungi. After performing the screening program, 4 Actinobacteria that hadall the desired criteriawere selected. Using the polyphasic approach, the taxonomic position of the selected Streptomyces AS25, isolated from rhizospheric soil of Alyssum spinosum, showed that it belongs to Streptomyces genus with 100% partial 16S similarity with Streptomyces albidoflavus NBRC13010. On the basis of HPLC and mass spectrometry, the purified compound produced by Streptomyces AS25 was identified as a non-polyenic lactone, antimycin A19, which has been found for the first time to be produced by Streptomyces albidoflavus strain. Following the obtained results, it is important to note that our screening criteria for non-polyenic antifungals have been validated and the rhizospheric soil represents an interesting source to isolate Actinobacteria.

Resistance to and accumulation of heavy metals by actinobacteria isolated from abandoned mining areas.

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).

Endophytic actinomycetes from spontaneous plants of Algerian Sahara: indole-3-acetic acid production and tomato plants growth promoting activity.

Twenty-seven endophytic actinomycete strains were isolated from five spontaneous plants well adapted to the poor sandy soil and arid climatic conditions of the Algerian Sahara. Morphological and chemotaxonomical analysis indicated that twenty-two isolates belonged to the Streptomyces genus and the remaining five were non-Streptomyces. All endophytic strains were screened for their ability to produce indole-3-acetic acid (IAA) in vitro on a chemically defined medium. Eighteen strains were able to produce IAA and the maximum production occurred with the Streptomyces sp. PT2 strain. The IAA produced was further extracted, partially purified and confirmed by thin layer chromatography (TLC) analysis. The 16S rDNA sequence analysis and phylogenetic studies indicated that strain PT2 was closely related to Streptomyces enissocaecilis NRRL B 16365(T), Streptomyces rochei NBRC 12908(T) and Streptomyces plicatus NBRC 13071(T), with 99.52 % similarity. The production of IAA was affected by cultural conditions such as temperature, pH, incubation period and L-tryptophan concentration. The highest level of IAA production (127 µg/ml) was obtained by cultivating the Streptomyces sp. PT2 strain in yeast extract-tryptone broth supplemented with 5 mg L-tryptophan/ml at pH 7 and incubated on a rotary shaker (200 rpm) at 30 °C for 5 days. Twenty-four-hour treatment of tomato cv. Marmande seeds with the supernatant culture of Streptomyces sp. PT2 that contained the crude IAA showed the maximum effect in promoting seed germination and root elongation.

Control of potato soft rot caused by Pectobacterium carotovorum and Pectobacterium atrosepticum by Moroccan actinobacteria isolates.

Pectobacterium carotovorum and Pectobacterium atrosepticum are dreadful causal agents of potato soft rot. Actually, there are no efficient bactericides used to protect potato against Pectobacterium spp. Biological control using actinobacteria could be an interesting approach to manage this disease. Thus, two hundred actinobacteria isolated from Moroccan habitats were tested for their ability to inhibit in vitro 4 environmental Pectobacterium strains and the two reference strains (P. carotovorum CFBP 5890 and P. atrosepticum CFBP 5889). Eight percent of these isolates were active against at least one of the tested pathogens and only 2% exhibited an antimicrobial activity against all tested Pectobacterium strains. Four bioactive isolates having the greatest pathogen inhibitory capabilities and classified as belonging to the genus Streptomyces species through 16S rDNA analysis were subsequently tested for their ability to reduce in vivo soft rot symptoms on potato slices of Bintje, Yukon Gold, Russet and Norland cultivars caused by the two pathogens P. carotovorum and P. atrosepticum. This test was carried out by using biomass inoculums and culture filtrate of the isolates as treatment. Among these, strain Streptomyces sp. OE7, reduced by 65-94% symptom severity caused by the two pathogens on potato slices. Streptomyces OE7 showed a potential for controlling soft rot on potato slices and could be useful in an integrated control program against potato soft rot pathogens in the objective to reduce treatments with chemical compounds.

Toxic and signalling effects of oxalic acid: Oxalic acid-Natural born killer or natural born protector?

Oxalic acid is thought to be a key factor of the early pathogenic stage in a wide range of necrotrophic fungi. We have recently published that oxalic acid induces Programmed Cell Death (PCD) in Arabidopsis thaliana cells. This cell death results from an early anionic efflux which is a prerequisite for the synthesis of ethylene and the PCD. Complementary experiments have been carried out by using seedlings of A. thaliana. The effects of millimolar concentrations of oxalic acid were analysed on A. thaliana seedlings. A treatment with a 3 mM oxalic acid solution does not alter the development of the plants but induces the transcription of defence related genes which are anion channel dependant. Moreover, our results suggest that a pre-treatment of the seedlings with oxalic acid is able to confer the resistance of A. thaliana against Sclerotium rolfsii. Regarding our results, we suggest that oxalic acid plays two distinct roles, depending on the concentration: a high concentration of oxalic acid induces a large PCD and then contribute to the progression of the fungi. However, at low concentration it is able to induce the establishment of a resistance of the plant against the fungi.