Integrated Transcriptome and Metabolome Analysis Revealed the Key Role of the Flavonoid Biosynthesis in Olive Defense Against Alternaria alternata.

The olive tree is an important oil woody plant with high economic value, yet it is vulnerable to the attack of numerous fungi. The successful control of olive fungal diseases requires a comprehensive understanding of the disease resistance mechanisms in plants. Here, we isolated Alternaria alternata from the diseased leaves of olive plants, and screened a resistant ("Leccino") and susceptible ("Manzanilla de Sevilla") cultivar from eight olive cultivars to explore their resistance mechanisms. Transcriptomic and metabolomic analyses identified the flavonoid biosynthesis as a key defense pathway against A. alternata. Five important transcription factors associated with flavonoid biosynthesis were also determined. The overexpression of OeWRKY40 significantly enhanced the disease resistance of the susceptible cultivar and upregulated the expression of genes involved in flavonoid biosynthesis and the accumulation of related metabolites. LUC assays further proved that OeWRKY40 can activate the expression of OeC4H. These results help to better clarify the molecular mechanisms of flavonoid biosynthesis against A. alternata. Our study provides key information for further exploration of the molecular pathways of olive plants and their resistance to fungi, an important factor for molecular breeding and utilization of resistant cultivars.

Optimization of Different Extraction Methods for Phenolic Compound Verbascoside from Chinese Olea europaea Leaves Using Deep Eutectic Solvents: Impact on Antioxidant and Anticancer Activities.

Chinese Olea europaea leaves, rich in verbascosides, were extracted using ultrasound-assisted extraction (UAE) and wall-breaking extraction (WBE) with deep eutectic solvents (Optimal UAE: 55 min, 200 mL/g liquid-solid ratio, 20% moisture, yielding 206.23 ± 0.58 mg GAE/g total phenolic content (TPC) and 1.59 ± 0.04% verbascoside yield (VAY); Optimal WBE: 140 s, 210 mL/g, 30% moisture, giving 210.69 ± 0.97 mg GAE/g TPC and 1.33 ± 0.2% VAY). HPLC analysis showed that young leaves accumulated higher TPC and phenolic compounds. Among the five olive varieties, Koroneiki and Chemlal showed the highest TPC in UAE, while Arbosana and Chemlal excelled in WBE. WBE yielded a higher TPC and rutin, whereas UAE marginally increased other phenolics. Additionally, the DPPH• assay showed that WBE-extracted verbascoside-rich extracts (VREs) of Chemlal exhibited high antioxidant activity (EC50 of 57 mg/mL), but Koroneiki-VREs exhibited lower activity against the ABTS•+ radical (EC50 of 134 mg/mL). Remarkably, the UAE/WBE-extracted Chemlal-VREs promoted the normal esophageal Het-1A cell line at 25 µg/mL for 24 h; yet, the esophageal cancer Eca-109 cells were sensibly inhibited, especially at 50 µg/mL; and the cell viability decreased dramatically. The results confirmed WBE as a relatively efficient method, and the Chemlal variety may be an excellent source of verbascoside.

Effect of ultrasound-attenuation on technological and functional properties of two strains of Lactiplantibacillus plantarum isolated from table olives.

While probiotics have a wide range of beneficial properties, they can also negatively affect the taste or aroma of foods products by resulting in the phenomenon of post-acidification. Ultrasound (US) is a tool to modulate the metabolism of probiotic bacteria, counteracting post-acidification and improving the performance and functional properties of microorganisms without affecting their viability. The purpose of this paper was to evaluate the effect of 10 different combinations of power (20 and 40 %) and duration (2, 4, 6, 8 and 10 min) of US treatment on two functional strains of Lactiplantibacillus plantarum (c16 and c19) isolated from table olives, with the aim of understanding how, some of the main functional and technological traits (viability, acidification, growth profile under different conditions, antibiotic resistance, viability at pH 2.0 and 0.3 % bile salts), were affected. It was found that the effects were strain dependent, and the best results were obtained for strain c19 in the combinations at 20 % for 8 and 10 min and 40 % for 2 min, where an improvement in functional characteristics was found, with some effects on biofilm stability, inhibition of acidification, without adverse results on some technological properties.

Olive Leaves as a Source of Anticancer Compounds: In Vitro Evidence and Mechanisms.

Olive trees not only produce olives but also generate a substantial amount of waste and by-products, including leaves, pomace (the solid remains after pressing olives for oil), and wastewater from the olive oil-making process. The waste products, particularly the leaves, contain bioactive compounds, especially phenolic compounds, known for their health benefits, such as high antioxidant potential and the ability to reduce inflammation. These compounds have shown promise in preventing and treating cancer. This review, based on in vitro evidence, provides a detailed description and discussion of the mechanisms through which these compounds from olive leaves can prevent development, the ways they might act against cancer cells, and their potential to increase the sensitivity of tumor cells to conventional anticancer therapy. The possible synergistic effects of these compounds suggest that olive leaf extracts may offer a promising approach for cancer treatment, compared with isolated compounds, thus providing novel possibilities for cancer therapy.

Pollen-Food Allergy Syndrome: From Food Avoidance to Deciphering the Potential Cross-Reactivity between Pru p 3 and Ole e 7.

BACKGROUND: Cross-reactivity between nonspecific lipid transfer proteins could cause anaphylaxis, further influencing food avoidance and nutrient deficiencies. The one affecting olive pollen (Ole e 7) and peach (Pru p 3) may underlie a variety of pollen-food syndromes, though a deep molecular analysis is necessary. METHODS: Three Ole e 7-monosensitised patients (MON_OLE), three Pru p 3-monosensitised patients (MON_PRU) and three bisensitised patients (BI) were selected. For epitope mapping, both digested proteins were incubated with patient sera, and the captured IgE-bound peptides were characterised by LC-MS. RESULTS: The analysis revealed two Ole e 7 epitopes and the three Pru p 3 epitopes previously described. Interestingly, the "KSALALVGNKV" Ole e 7 peptide was recognised by MON_OLE, BI and MON_PRU patients. Conversely, all patients recognised the "ISASTNCATVK" Pru p 3 peptide. Although complete sequence alignment between both proteins revealed 32.6% identity, local alignment considering seven residue fragments showed 50 and 57% identity when comparing "ISASTNCATVK" with Ole e 7 and "KSALALVGNKV" with Pru p 3. CONCLUSIONS: This study mapped sIgE-Ole e 7-binding epitopes, paving the way for more precise diagnostic tools. Assuming non-significant sequence similarity, structural homology and shared key residues may underlie the potential cross-reactivity between Ole e 7 and Pru p 3 nsLTPs.

From Waste to Health: Olive Mill Wastewater for Cardiovascular Disease Prevention.

Waste from the agri-food chain represents a valuable reservoir of organic compounds with health-promoting properties. Momast Plus 30 Bio (MP30B) is a derivative obtained from olive-oil wastewater. Its enrichment in hydroxytyrosol (HT) via a patented technique has paved the way for its potential application as a dietary supplement in preventing cardiovascular diseases. MP30B demonstrates no significant alteration in cardiac and vascular parameters in "ex vivo" studies. However, it exhibits a strong ability to remove reactive oxygen species and exerts anti-inflammatory effects, notably reducing the concentration of iNOS and mitigating heart infections in "in vitro" experiments. Furthermore, MP30B slightly decreases the stiffness of the "ex vivo" thoracic aorta, potentially resulting in lowered arterial pressure and enhanced energy transfer to a normal ventricle. Based on these findings, we posit MP30B as a promising extract for cardiovascular disease prevention, and its specific antibacterial properties suggest its utility in preventing cardiac infections.

HPTLC-guided flash chromatographic isolation and spectroscopic identification of bioactive compounds from olive flowers.

The goal of preparative chromatography is to isolate suitable amounts of compound(s) at the required purity in the most cost-effective way. This study analyses the power of High-performance thin-layer chromatography (HPTLC) guided preparative flash chromatography to separate and isolate bioactive compounds from an olive flower extract for their further characterisation via spectroscopy. The structure and purity of isolated bioactive compounds were assessed using Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. Flash chromatography of the olive flower extract successfully isolated pure oleanolic and maslinic acids. Moreover, the flash chromatography of the extract allowed isolation and phytochemical analysis of the most lipophilic fraction of the extract, which was found to contain n-eicosane and n-(Z)-eicos-5-ene, that has not been isolated previously with preparative TLC.

Effect of temperature on in vitro germination and growth of Colletotrichum fioriniae, a new emerging pathogen of olive fruits.

Olive anthracnose induced by different Colletotrichum species causes dramatic losses of fruit yield and oil quality. The increasing incidence of Colletotrichum fioriniae (Colletotrichum acutatum species complex) as causal agent of olive anthracnose in Italy, is endorsing new studies on its biology, ecology, and environmental factors such as temperature. Five isolates from different sampling sites in Lazio region (Central Italy) were studied under controlled laboratory conditions aiming to better understand the differences of thermal development among the isolates and to lay the foundations of a future mathematical model able to describe the key aspects of the pathogen's life cycle. The mycelial growth rate and the conidial germination rate were assessed at seven different constant temperatures (5, 10, 15, 20, 25, 30, and 35°C) and fixed relative humidity (100% RH). The obtained dataset was analysed to estimate the parameters of mathematical functions that connect the mycelial growth rate and the spore germination with the environmental temperature. The parameters set provided as the result of this study constitute a key step forward in the biological knowledge of the species and the basis for future formulations of mathematical models that might be the core of decision support systems in an integrated pest management framework.

Enzymatic synthesis of Hydroxytyrosol from Oleuropein for valorization of an agricultural waste.

Oleuropein (OP) is an appreciated compound present not only in fruits but also in leaves of olive trees, which can be transformed into hydroxytyrosol (HT), a substance with high antioxidant activity. In this work, the transformation of an agricultural residue containing OP (olive leaves or wastewater from mills) to the high added value compound HT is accomplished through different enzymatic strategies. Different enzymes were used, immobilized on various supports by diverse binding forces: beta-glucosidase encapsulated in siliceous material, esterases and lipases immobilized on hydrophobic supports (octyl-functionalized amorphous silica and periodic mesoporous organosilica), and esterase immobilized on amine-functionalized ordered mesoporous silica. All these biocatalysts were tested for oleuropein hydrolysis through two different reaction approaches: a) split of glucosidic bond catalyzed by beta-glucosidase (ß-glu), followed by hydrolysis of the aglycon and further ester hydrolysis. 5 mg·mL-1 of ß-glu fully hydrolyzed 5 mM OP at pH 7 and 50°C in 7 days, and further enzymatic hydrolysis of the aglycon yielded near to 0.5 mM HT in the best conditions tested. b) via direct hydrolysis of the ester bond to produce hydroxytyrosol in a one-step reaction using esterases or lipases. The latter reaction pathway catalyzed by lipase from Penicillium camemberti immobilized on octyl-silica (4 mg·mL-1) at 35°C and pH 6 directly produced 6.8 mM HT (1 mg·mL-1), transforming in 12 days near to 30% of the initial 25 mM OP from a commercial olive leaves extract.

Phytochemical Characterization of Two New Olive Oil Genotypes Growing in Southern Tunisia.

This research can be considered as the first complete survey for the valorization of new olive genotypes cultivated in the South-East of Tunisia as well as their oils. The study aimed to characterize the phytochemical composition of virgin olive oil produced from two olive cultivars, namely Nourgou and Gousalani. The pomological characterization of fruits, the quality criteria and the phytochemical profile were quantified. Additionally, antioxidant activity was evaluated using Ferric reducing antioxidant power (FRAP) and Oxygen radical absorbance capacity (ORAC) tests to also obtain a bioactive characterization of these monovarietal olive oils. The obtained results revealed that the analyzed olive oils samples can be classified into Extra Virgin category (EVOO) according to the regulated physicochemical characteristics. Our findings showed a significant variability in the chemical parameters of the analyzed EVOO likely associated with the genetic potential, mainly for chlorophylls contents (1.37-1.64 mg/kg), in carotenoids pigments (3.97-10.86 mg/kg), in α-tocopherol (175.59-186.87 mg/kg), in sterols (1036.4-1931.4 mg/kg) in oleic acid (65.33-68.73%), in palmitic acid (C16:0) (13.32-17.48%), in linoleic acid (C18:2) (11.06-13.47%). Additionally, the HPLC-MS/MS analysis showed that the two EVOOs analyzed contained appreciable amounts of total polyphenols, ranging from 348.03 up to 516.16 mg/kg, in Nourgou and Gousalani oils, respectively. Regarding the individual phenolic compounds, the EVOO samples were mainly characterized by phenolic alcohols, phenolic acids, secoiridoids, verbascoside, flavonoids and phenolic aldehydes. The prevalent simple phenolics detected were secoiridoids with the dominance of the oleuropein aglycone in Gousalani oil. In addition, findings from in vitro antioxidant assays (FRAP and ORAC) revealed that the two studied oils possessed a powerful antiradical activity and a good reducing power capacity. In conclusion, these new EVOOs exhibited a superior quality compared to other Tunisian varieties, considering their antiradical activity and reducing power capacity.

Tapping into haloalkaliphilic bacteria for sustainable agriculture in treated wastewater: insights into genomic fitness and environmental adaptation.

The increasing salinity and alkalinity of soils pose a global challenge, particularly in arid regions such as Tunisia, where about 50% of lands are sensitive to soil salinization. Anthropogenic activities, including the use of treated wastewater (TWW) for irrigation, exacerbate these issues. Haloalkaliphilic bacteria, adapted to TWW conditions and exhibiting plant-growth promotion (PGP) and biocontrol traits, could offer solutions. In this study, 24 haloalkaliphilic bacterial strains were isolated from rhizosphere sample of olive tree irrigated with TWW for more than 20 years. The bacterial identification using 16S rRNA gene sequencing showed that the haloalkaliphilic isolates, capable of thriving in high salinity and alkaline pH, were primarily affiliated to Bacillota (Oceanobacillus and Staphylococcus). Notably, these strains exhibited biofertilization and enzyme production under both normal and saline conditions. Traits such as phosphate solubilization, and the production of exopolysaccharide, siderophore, ammonia, and hydrogen cyanide were observed. The strains also demonstrated enzymatic activities, including protease, amylase, and esterase. Four selected haloalkaliphilic PGPR strains displayed antifungal activity against Alternaria terricola, with three showing tolerances to heavy metals and pesticides. The strain Oceanobacillus picturea M4W.A2 was selected for genome sequencing. Phylogenomic analyses indicated that the extreme environmental conditions probably influenced the development of specific adaptations in M4W.A2 strain, differentiating it from other Oceanobacillus picturae strains. The presence of the key genes associated with plant growth promotion, osmotic and oxidative stress tolerance, antibiotic and heavy metals resistance hinted the functional capabilities might help the strain M4W.A2 to thrive in TWW-irrigated soils. By demonstrating this connection, we aim to improve our understanding of genomic fitness to stressed environments. Moreover, the identification of gene duplication and horizontal gene transfer events through mobile genetic elements allow the comprehension of these adaptation dynamics. This study reveals that haloalkaliphilc bacteria from TWW-irrigated rhizosphere exhibit plant-growth promotion and biocontrol traits, with genomic adaptations enabling their survival in high salinity and alkaline conditions, offering potential solutions for soil salinization issues.

Use of micro-computed tomography to monitor olive fruit damage caused by three insect pests.

A complete three-dimensional reconstruction of the internal damage (oviposition holes, entry and exit galleries, cavities caused by fungal infection) of three destructive pests of olive fruit was obtained using micro-computed tomography. In the case of the olive fruit fly (Bactrocera oleae), complete reconstruction of the galleries was achieved. The galleries were colour-coded according to the size of the internal lumens produced by larval instars. In the case of the olive moth (Prays oleae), we confirmed that the larvae only consume olive stones, leaving pulp tissue intact. This study revealed the evolutionary defensive adaptation developed by larvae, creating entrance/exit gallery in the form of a zigzag with alternating angles to avoid the action of possible parasitoids. In the case of olive fruit rot, caused by fungal infection transmitted by the midge (Lasioptera berlesiana), microtomography revealed the infection cavity, which was delimited by a protective layer of tissue produced by the plant to isolate the infection zone, which contained fungal hyphae and reproductive organs of the fungus. Two ovoid cavities were observed below a single external orifice in the concave necrotic depression. These results were interpreted as successive ovipositions of B. oleae, followed by the parasitoid L. berlesiana. High-resolution 3D rendered images are included as well as supplementary videos that could be useful tools for future research and teaching aids.

Coordination between water relations strategy and carbon investment in leaf and stem in six fruit tree species.

The water relation strategy is a key issue in climate change. Given the difficulty of determining water relations strategy, there is a need for simple traits with a solid theoretical basis to estimate it. Traits associated with resource allocation patterns along a 'fast-slow' plant economics spectrum are particularly compelling, reflecting trade-offs between growth rate and carbon allocation. Avocado (Persea americana ), fig tree (Ficus carica ), mandarin (Citrus reticulata ), olive (Olea europaea ), pomegranate (Punica granatum ), and grapevine (Vitis vinifera ) were characterised in terms of iso-anisohydric strategy through stomatal behaviour, water potential at the turgor loss point (TLP), and hydroscape area. Additionally, the association of these metrics with leaf mass per area (LMA) and wood density (WDen) was explored. We observed high coordination between LMA and WDen, and both traits were related to metrics of water relation strategy. More anisohydric species tended to invest more carbon per unit leaf area or unit stem volume, which has implications for hydraulic efficiency and water stress tolerance. WDen and TLP were the most powerful traits in estimating the water relation strategy for six fruit species. These traits are easy to measure, time-cost efficient, and appear central to coordinating multiple traits and behaviours along the water relations strategies.

Antioxidant and anti-cancer potentials of Ag green-synthesized and encapsulated olive leaves particles on HCT-116 cells.

Water extracts (OLE), whey protein encapsulated extracts (OLE/WPNs), and silver nanoparticles (OLE/Ag-NPs) were prepared from olive leaves of Manzenllie and Picual varieties. These preparations were characterized, and their antioxidant and biological activities on Vero and HCT-116 colorectal cells were assessed. The mechanism of action of the preparations was studied through tumor necrosis factor-α (TNF-α) and cytochrome C oxidase (Cox1) gene expression. OLE/Ag-NPs showed smaller particle sizes (14.23-15.53 nm) than OLE/WPNs (229.83-310.67 nm) and demonstrated lower aggregation due to their high Ƹ-potential of -24.86 to -27.90 mV. None of the preparations affected the viability of Vero cells (IC50 = 192.19-421.01 µg/mL), but they showed cytotoxic effects on HCT-116 cells (IC50 = 50.76-196.54 µg/mL), particularly OLE/WPNs. Moreover, the preparations from the Picual variety (OLE, OLE/WPNs, and OLE/Ag-NPs) showed regulatory effects against colon cancer on treated HCT-116 cells by upregulating Cox1 expression and downregulating TNF-α expression. Consequently, OLE/WPNs and OLE/Ag-NPs could be promising for industrial applications with potential health benefits.

Comparison of Olea pollen sampling between gravimetric and volumetric traps (NW of Morocco).

Olea pollen is considered one of the most critical causes of respiratory allergic disease in the Mediterranean region, contributing to different symptoms in allergic sufferers. Due to the high increase in the prevalence of olive pollen caused by the expansion of cultivated areas especially in the Mediterranean region, the aim of this study was to examine the Olea pollen sampling efficiency between gravimetric and volumetric pollen traps over the period 2018-2022. Our data demonstrated that Olea pollen season start-date was generally recorded earlier with volumetric trap than shown with gravimetric method. Moreover, the peak dates occurred mainly in May for the years studied. Across the entire period, the greatest pollen concentrations were reached in the week 11th and >60 % of the total Olea pollen were already reached after the ninth week of sampling in 2020. In general, the evolution of pollen sampling for both methods demonstrates similar temporal development. Variations in the seasonal pollen integral could be attributed to the elevation above ground level at which the traps were placed, exposure to regional winds, the influence of long-range transported pollen and the mode of pollen transport. The findings indicate that the gravimetric method was equally practical as the volumetric method in estimating airborne pollen.

A multilevel LC-HRMS and NMR correlation workflow towards foodomics advancement: Application in table olives.

Foodomics employs advanced analytical techniques to provide answers regarding food composition, authenticity control, marker identification and issues related to food quality and safety. Nuclear magnetic resonance (NMR) spectroscopy and chromatography hyphenated to mass spectrometry (MS) are the main analytical platforms used in this field. Nevertheless, they are rarely employed in an integrated manner, and even then, the contribution of each technique remains vague. Table olives (Olea europaea L.) are a food commodity of high economic and nutritional value with an increasing production tendency over the last two decades, which, however, suffers from extensive fraud incidents and quality determination uncertainties. Thus, the current attempt aims towards two axes with the first being the multilevel integration of LC-HRMS and NMR data of the same samples and table olives being the selected matrix. In more detail, UPLC-HRMS/MS-based analysis was compared at different stages within an untargeted metabolomics workflow with an NMR-based study and the complementarity of the two platforms was evaluated. Furthermore, statistical heterospectroscopy (SHY), rarely employed in foodomics, combining the spectroscopic with spectrometric datasets and aiming to increase the confidence level of annotated biomarkers was applied. Amongst these lines, the second parallel axis of this study was the detailed characterization of table olives' metabolome in search for quality markers considering the impact of geographical (from Northern to Southern Greece) and botanical origin (Kalamon, Konservolia, Chalkidikis cultivars), as well as processing parameters (Spanish, Greek). To that end, using deep dereplication tools including statistical methods, with SHY employed for the first time in table olives, different biomarkers, belonging to the classes of phenyl alcohols, phenylpropanoids, flavonoids, secoiridoids and triterpenoids were identified as responsible for the observed classifications. The current binary pipeline, focusing on biomarkers' identification confidence, could be suggested as a meaningful workflow not only in olive-based products, but also in food quality control and foodomics in general.

Incubating frozen-thawed buffalo sperm with olive fruit extracts counteracts thawing-induced oxidative stress and improves semen quality.

Freezing-thawing procedures and semen manipulation for in vitro fertilization induce oxidative stress, which in turn leads to impaired sperm quality. The aim of this study was to evaluate whether incubation of frozen-thawed buffalo semen with olive fruit extracts (OFE), known to contain a high concentration of phenolic antioxidants, would improve semen quality by reducing oxidative stress. Frozen sperm (4 ejaculates/4 bulls/3 replicates) were thawed and diluted to 30 × 106/mL in IVF medium with 0, 72, 143, and 214 µL/mL of OFE, corresponding to 0 (D0-control), 50 (D50), 100 (D100), and 150 (D150) µM hydroxytyrosol. Sperm viability, acrosome integrity, membrane functionality, motility, and sperm kinetics were evaluated immediately after thawing (T0) and after 1 (T1) and 2 h (T2) of incubation at 38.7 °C. Based on the results, sperm biological antioxidant potential (BAP) and ROS levels (ROMs) were assessed in D0 and D100 groups at T1 and T2. To assess the effect of OFE on fertilizing ability, heterologous penetration rates were also evaluated, using bovine abattoir-derived oocytes. The treatment with OFE at all concentrations tested increased (P < 0.05) the percentage of acrosome intact spermatozoa compared to the D0-control at T1, but the effect was more evident (P < 0.01) with D100 (54.5 ± 3.0, 60.5 ± 1.5, 65.2 ± 3.3, and 62.5 ± 1.7, with D0, D50, D100, and D150 OFE, respectively). Total motility, progressive motility, rapid velocity, and progressive velocity decreased (P < 0.05) at T2 only in the D0-control group. The percentage of rapidly progressive sperm and the progressive motility tended to increase (P < 0.10) at T1 and T2, respectively, in D100 compared to D0 (24.7 ± 4.1 vs 16.4 ± 1.6 and 22.8 ± 2.7 vs 17.0 ± 1.2, respectively). The treatment with D100 OFE of frozen-thawed sperm increased (P < 0.05) some kinetic parameters (VAP and WOB). Spermatozoa incubated with D100 OFE exhibited higher (P < 0.01) total and normospermic oocyte penetration rates compared to D0 (86.5 ± 1.4 vs 78.5 ± 0.7, and 70.6 ± 1.5 vs 63.8 ± 1.1, respectively). Additionally, D100 OFE increased sperm BAP concentrations at both T1 and T2, while ROS levels were unaffected. These results suggest that incubating frozen-thawed buffalo semen with OFE is an effective strategy for preserving semen quality and in vitro fertilization ability by enhancing sperm antioxidant capacity.

Rhizobacterial diversity of Portuguese olive cultivars in the Douro valley and their potential as plant growth promoters.

AIMS: This study investigated the bacterial communities in the rhizosphere of two traditional Portuguese olive cultivars, Cobrançosa and Negrinha de Freixo, in relation to soil properties. Additionally, we aimed to isolate and identify bacteria with potential for biocontrol and other plant growth-promoting traits from these rhizosphere communities. METHODS AND RESULTS: Bacterial communities in the olive rhizosphere were investigated using a metabarcoding approach and the soil physicochemical properties of the olive groves were also analyzed. Higher bacterial richness was associated with Negrinha de Freixo growing in soil with high organic matter content and water-holding capacity. In contrast, the soils of the Cobrançosa grove presented higher pH and electric conductivity. Negrinha de Freixo rhizosphere was enriched with ASVs (Amplicon Sequence Variants) belonging to Bacillus, Gaiella, Acidothermus, Bradyrhizobium, and uncultured Xanthobacteraceae. On the other hand, the Cobrançosa rhizosphere was characterized by higher relative abundance of Streptomyces and Sphingomonas. Bacterial isolation from the rhizosphere and screening for plant growth-promoting activities were also performed. Six bacteria strains, predominantly Bacillus isolated from Negrinha de Freixo, demonstrated antagonistic activities against the olive fungal pathogen Colletotrichum gloeosporoides and other plant growth promotion (PGP) traits. CONCLUSIONS: Our findings demonstrate that the structure of rhizosphere bacterial communities associated with olive trees is shaped by both plant cultivar and soil-related factors. The higher number of bacterial species in the rhizosphere of Negrinha de Freixo was related to a higher organic matter content and a greater abundance of isolates with plant growth promotion traits, particularly Bacillus strains.

Degradation of antipyrine in water with activated persulfate aided with biochar of olive pomace.

The degradation of antipyrine (AP) in water has been studied using persulfate activated with biochar obtained from gasification of olive pomace (BC) combined with ferric salts in the presence of UV-A radiation. Firstly, the adsorption of AP on biochar was evaluated. The data were adjusted using various kinetic models verifying that AP adsorption on BC occurs in three stages and follows pseudo-second order kinetics. Degradation tests show that the presence of iron or persulfate (PS) in binary systems with BC produces increases AP degradation when no radiation is used, reaching 75.7 % due to the ability of BC to donate electrons. On the other hand, addition of PS showed an increase in efficiency in the presence of BC (up to 79%). For ternary systems the best result was found when UVA/PS/Fe was used (100% of AP degradation in 30 min). The addition of UV-A radiation to the BC/PS system improves the degradation of the contaminant by only 6.7%, while the presence of iron in the studied conditions does not cause any improvement. A Central Composite Factorial Design of experiments was used to optimize the UVA/BC/PS/Fe system, leading to an 89.3% AP degradation rate in 90 min (k = 0.0134 min-1) under optimal conditions ([Fe(III)] = 10 mg/L, [PS] = 379 mg/L, [BC] = 500 mg/L). Although the best results were obtained for the UVA/PS/Fe process without BC, systems based on BC/PS can be considered as an alternative in cloudy days or when simple processes are selected due to economical/technical reasons.

Anticancer Effects of Secoiridoids-A Scoping Review of the Molecular Mechanisms behind the Chemopreventive Effects of the Olive Tree Components Oleocanthal, Oleacein, and Oleuropein.

The olive tree (Olea europaea) and olive oil hold significant cultural and historical importance in Europe. The health benefits associated with olive oil consumption have been well documented. This paper explores the mechanisms of the anti-cancer effects of olive oil and olive leaf, focusing on their key bioactive compounds, namely oleocanthal, oleacein, and oleuropein. The chemopreventive potential of oleocanthal, oleacein, and oleuropein is comprehensively examined through this systematic review. We conducted a systematic literature search to identify eligible articles from Scopus, PubMed, and Web of Science databases published up to 10 October 2023. Among 4037 identified articles, there were 88 eligible articles describing mechanisms of chemopreventive effects of oleocanthal, oleacein, and oleuropein. These compounds have the ability to inhibit cell proliferation, induce cell death (apoptosis, autophagy, and necrosis), inhibit angiogenesis, suppress tumor metastasis, and modulate cancer-associated signalling pathways. Additionally, oleocanthal and oleuropein were also reported to disrupt redox hemostasis. This review provides insights into the chemopreventive mechanisms of O. europaea-derived secoiridoids, shedding light on their role in chemoprevention. The bioactivities summarized in the paper support the epidemiological evidence demonstrating a negative correlation between olive oil consumption and cancer risk. Furthermore, the mapped and summarized secondary signalling pathways may provide information to elucidate new synergies with other chemopreventive agents to complement chemotherapies and develop novel nutrition-based anti-cancer approaches.