The anti-staphylococcal fusidic acid as an efflux pump inhibitor combined with fluconazole against vaginal candidiasis in mouse model

BACKGROUND

Candida albicans is the most common fungus that causes vaginal candidiasis in immunocompetent women and catastrophic infections in immunocompromised patients. The treatment of such infections is hindered due to the increasing emergence of resistance to azoles in C. albicans. New treatment approaches are needed to combat candidiasis especially in the dwindled supply of new effective and safe antifungals. The resistance to azoles is mainly attributed to export of azoles outside the cells by means of the efflux pump that confers cross resistance to all azoles including fluconazole (FLC).

OBJECTIVES

This study aimed to investigate the possible efflux pump inhibiting activity of fusidic acid (FA) in C. albicans resistant isolates and the potential use of Fusidic acid in combination with fluconazole to potentiate the antifungal activity of fluconazole to restore its activity in the resistant C. albicans isolates.

METHODS

The resistance of C. albicans isolates was assessed by determination of minimum inhibitory concentration. The effect of Fusidic acid at sub-inhibitory concentration on efflux activity was assayed by rhodamine 6G efflux assay and intracellular accumulation. Mice model studies were conducted to evaluate the anti-efflux activity of Fusidic acid and its synergistic effects in combination with fluconazole. Impact of Fusidic acid on ergosterol biosynthesis was quantified. The synergy of fluconazole when combined with Fusidic acid was investigated by determination of minimum inhibitory concentration. The cytotoxicity of Fusidic acid was tested against erythrocytes. The effect of Fusidic acid on efflux pumps was tested at the molecular level by real-time PCR and in silico study. In vivo vulvovaginitis mice model was used to confirm the activity of the combination in treating vulvovaginal candidiasis.

RESULTS

Fusidic acid showed efflux inhibiting activity as it increased the accumulation of rhodamine 6G, a substrate for ABC-efflux transporter, and decreased its efflux in C. albicans cells. The antifungal activity of fluconazole was synergized when combined with Fusidic acid. Fusidic acid exerted only minimal cytotoxicity on human erythrocytes indicating its safety. The FA efflux inhibitory activity could be owed to its ability to interfere with efflux protein transporters as revealed by docking studies and downregulation of the efflux-encoding genes of both ABC transporters and MFS superfamily. Moreover, in vivo mice model showed that using fluconazole-fusidic acid combination by vaginal route enhanced fluconazole antifungal activity as shown by lowered fungal burden and a negligible histopathological change in vaginal tissue.

CONCLUSION

The current findings highlight FA's potential as a potential adjuvant to FLC in the treatment of vulvovaginal candidiasis.

Eco-friendly approach to decrease the harmful effects of untreated wastewater on growth, yield, biochemical constituents, and heavy metal contents of carrot (Daucus carota L.)

Here, the impact of irrigation using untreated wastewater (WW) on carrots (Daucus carota L.) was examined. We hypothesized that the addition of ethylenediaminetetraacetic acid (EDTA), dry algal powder (Spirulina platensis or Chlorella vulgaris), and Salix alba leaves powder would function as chelators for harmful contaminants in wastewater. The findings showed that irrigation of carrot plants with the sampled untreated wastewater led to significant decreases in the shoot lengths, fresh, dry weights of shoots and roots at stage I, the diameter of roots, pigment content, carotenoids, total soluble carbohydrate content, and soluble protein content. Furthermore, a significantly increased level of proline, total phenols, and the activities of polyphenol oxidase (PPO), peroxidase (POX), superoxide dismutase (SOD), and catalase (CAT) was identified in stage I samples. In contrast to the stage I, the length of the roots, the number of leaves on each plant, wet and dry weights of the stage II roots were all greatly enhanced. In spite of the increased yield due to the wastewater irrigation, carrot roots irrigated with wastewater had significantly more cadmium (Cd), nickel (Ni), cobalt (Co), and lead (Pb) than is considered safe. Our data clearly show that the application of Spirulina platensis, Chlorella vulgaris, EDTA, and leaves powder of salix was able to alleviate the toxicity of wastewater on carrot plants. For example, we recorded a significant decrease in the accumulation of carrot's Cd, Ni, Co, and Pb contents. We conclude that the treatments with Spirulina platensis and Chlorella vulgaris can be utilized as eco-friendly tools to lessen the damaging effects of wastewater irrigation on carrot plants.

Performance evaluation of Moringa oleifera seeds aqueous extract for removing Microcystis aeruginosa and microcystins from municipal treated-water

Introduction: Toxic microcystins (MCs) produced by cyanoprokaryotes -particularly by the cosmopolitan cyanobacterium Microcystis aeruginosa- pose adverse effects on aquatic organisms and their ecosystem and may also cause serious impacts on human health. These harmful monocyclic heptapeptides are the most prevalent cyanotoxins reported in freshwaters and must be eliminated for avoiding MCs release in receiving water bodies. Hence, this work aimed to test the efficacy of Moringa oleifera seeds water-based extract (MO) as a natural coagulant for removing cyanobacteria (especially M. aeruginosa), microalgae, and its associated MCs from pre-treated municipal wastewaters. Methodology: Four different MO coagulant doses (25, 50, 75 and 100 mg L-1) were investigated for cyanobacteria and microalgae removal by conventional coagulation assays and morphology-based taxonomy studies. Additionally, water turbidity and chlorophyll a (Chl a) content were also determined. Further, the presence and concentration of MCs soluble in water, remaining in the particulate fraction, and flocculated within the residual sludge were assessed using high-performance liquid chromatography coupled with diode array detection (HPLC-DAD). Results: The treatment with MO at 100 mg L-1 substantially reduced the number of cyanobacterial and microalgal species in the treated samples (average removal rate of 93.8% and 86.9%, respectively). These results agreed with a ∼44% concomitant reduction in Chl a and ∼97% reduction in water turbidity (a surrogate marker for suspended solids content). Notably, MCs concentrations in the treated water were significantly lowered to 0.6 ± 0.1 µg L-1 after addition of 100 mg L-1 MO. This value is below the WHO recommended limits for MCs presence in drinking water (<1.0 µg L-1). Discussion: The present study provides promising insights into the applicability of MO as a cost-effective, reliable, and sustainable natural coagulant, particularly for using in developing countries, to eliminate harmful cyanobacteria and cyanotoxins in municipal water treatment facilities.

Polyphenols-Rich Extract of Calotropis procera Alone and in Combination with Trichoderma Culture Filtrate for Biocontrol of Cantaloupe Wilt and Root Rot Fungi

Fungal diseases have always been a major problem for cantaloupe crops; however, synthetic fungicides are hazardous to humans and the environment. Consequently, a feasible alternative to fungicides without side effects could be by using bio agents and naturally occurring plants with antibacterial potential. This study has achieved a novel procedure for managing wilt and root rot diseases by potentially using Trichoderma sp. culture filtrates in consortium with plant extract of Calotropis procera, Rhizoctonia solani, Fusarium oxysporum, and Pythium ultimum, which were isolated from infected cantaloupe roots with identified root rot symptoms. The antagonistic activity of four Trichoderma isolates and analysis of antibiotics and filtrate enzymes of the most active Trichoderma isolate were determined as well as phytochemical analysis of C. procera plant extract using HPLC-UV. The obtained results showed that all Trichoderma isolates considerably lowered the radial growth of P. ultimum, R. solani, and F. oxysporum in varying degrees. The scanning electron micrographs illustrate the mycoparasitic nature of Trichoderma sp. on F. oxysporum. The phytochemical analysis of C. procera indicated that phenolic contents were the major compounds found in extracts, such as vanillin (46.79%), chlorogenic acid (30.24%), gallic acid (8.06%), and daidzein (3.45%) but including only a low amount of the flavonoid compounds rutin, naringenin, and hesperetin. The Pot experiment's findings showed that cantaloupe was best protected against wilting and root rot diseases when it was treated with both Trichoderma sp. culture filtrates (10%) and C. procera extract of (15 mg/mL), both alone and in combination. This study demonstrates that the application of bio agent Trichoderma spp. filtrate with C. procera phenol extract appears useful for controlling wilting and root rot disease in cantaloupe. This innovative approach could be used as an alternative to chemical fungicide for the control of wilting and rot root diseases.

In vitro efficacy of Boswellia carterii resin extracts formulated as an emulsifiable concentrate against Tetranychus urticae and phytopathogenic fungi

Contemporary agriculture heavily relies on pesticides for pest eradication and disease management. Consequently, current study was carried out to assess the acaricidal/antifungal efficacy of emulsifiable concentrate (10 % EC) derived from Boswellia carterii (B. carterii) against adult females of Tetranychus urticae (T. urticae), and five fungal pathogens. The meticulous examination of the chemical constitution of the crude extracts derived from the resin of B. carterii was conducted through the employment of the venerable technique known as Gas-Liquid Chromatography (GLC). The formulated petroleum-ether extract (FPEE) and formulated ethyl-acetate extract (FEAE) of B. carterii at a concentration of 10 mg ml-1 exhibited notable antioxidant activity with rates of 62.0 % and 90.8 %, respectively. In vitro, the FEAE exhibited potent inhibition against all the tested phytopathogenic fungi at different concentrations, whereas FPEE showed comparatively less efficacy. Interestingly, at 4000 ppm concentration, FEAE completely ceased the mycelial growth compared with the control. Moreover, following a span of 72 h of intervention, FPEE exhibited a greater degree of toxicity towards mature females of the T. urticae. This was evidenced by the LC50 value of 422.52 parts per million (ppm) for FPEE, which surpassed the LC50 value of 539.50 ppm observed for FEAE. In summary, the present study indicates that B. carterii resin formulated as an emulsifiable concentrate (10 % EC) can offer a natural and effective alternative for integrated pest management, thereby reducing reliance on synthetic pesticides and offering a more environmentally sustainable strategy for pest control.

Multidrug resistant and multivirulent avian bacterial pathogens: tackling experimental leg disorders using phytobiotics and antibiotics alone or in combination

Locomotor disorders caused by multidrug-resistant (MDR) bacterial pathogens denote one of the most detrimental issues that collectively threaten the poultry industry leading to pronounced economic losses across the world. Hence, searching for effective alternatives, especially those extracted from plant origins became of great priority targeting a partial or complete replacement of chemical antimicrobials to tackle their developing resistance. Therefore, we aimed to determine the prevalence and antimicrobial resistance of Staphylococcus aureus (S. aureus), Salmonella species, Mycoplasma synoviae (M. synoviae), and Escherichia coli (E. coli) recovered from 500 broilers and ducks (250 each) with locomotor disorders in various farms in Dakahlia and Sharkia Governorates, Egypt. Additionally, we assessed, for the first time, the in vitro antimicrobial effectiveness of marjoram, garlic, ginger and cinnamon essential oils (EOs) against MDR and multivirulent bacterial isolates as well as the in vivo efficiency of the most effective antibiotics and EOs either separately or in combination in the treatment of experimentally induced poultry leg disorders. The overall prevalence rates of S. aureus, E. coli, Salmonella species, and M. synoviae were 54, 48, 36, and 2%, respectively. Salmonella species and S. aureus prevailed among ducks and broilers (36 and 76%, respectively). Notably, MDR was observed in 100, 91.7, 81.1, and 78.5% of M. synoviae, E. coli, Salmonella, and S. aureus isolates, respectively. Our in vitro results displayed that marjoram was the most forceful EO against MDR and multivirulent chicken vancomycin-resistant S. aureus (VRSA) and duck S. Typhimurium isolates. The current in vivo results declared that marjoram in combination with florfenicol or amoxicillin/clavulanic acid succeeded in relieving the induced duck and chicken leg disorders caused by S. Typhimurium and VRSA, respectively. This was evidenced by improvement in the clinical and histopathological pictures with a reduction of bacterial loads in the experimental birds. Our encountered successful in vitro and in vivo synergistic effectiveness of marjoram combined with florfenicol or amoxicillin/clavulanic acid recommends their therapeutic application for leg disorders and offers opportunities for reducing the antibiotics usage in the poultry industry.

Biochar improves the growth and physiological traits of alfalfa, amaranth and maize grown under salt stress

Purpose

Salinity is a main factor in decreasing seed germination, plant growth and yield. Salinity stress is a major problem for economic crops, as it can reduce crop yields and quality. Salinity stress occurs when the soil or water in which a crop is grown has a high salt content. Biochar improve plant growth and physiological traits under salt stress. The aim of the present study, the impact of biochar on growth, root morphological traits and physiological properties of alfalfa, amaranth and maize and soil enzyme activities under saline sands.

Methods

We studied the impact of biochar on plant growth and the physiological properties of alfalfa, amaranth and maize under salt stress conditions. After 40 days, plant growth parameters (plant height, shoot and root fresh weights), root morphological traits and physiological properties were measured. Soil nutrients such as the P, K and total N contents in soil and soil enzyme activities were analyzed.

Results

The results showed that the maize, alfalfa, and amaranth under biochar treatments significantly enhanced the plant height and root morphological traits over the control. The biochar on significantly increased the total root length, root diameter, and root volume. Compared to the control, the biochar significantly increased the chlorophyll a and b content, total chlorophyll and carotenoid content under salt stress. Furthermore, the biochar significantly increased enzyme activities of soil under salt stress in the three crops.

Conclusions

Biochar treatments promote plant growth and physiological traits of alfalfa, amaranth, and maize under the salt stress condition. Overall, biochar is an effective way to mitigate salinity stress in crops. It can help to reduce the amount of salt in the soil, improve the soil structure, and increase the availability of essential nutrients, which can all help to improve crop yields.

Therapeutic Switching of Rafoxanide: a New Approach To Fighting Drug-Resistant Bacteria and Fungi

Control and management of life-threatening bacterial and fungal infections are a global health challenge. Despite advances in antimicrobial therapies, treatment failures for resistant bacterial and fungal infections continue to increase. We aimed to repurpose the anthelmintic drug rafoxanide for use with existing therapeutic drugs to increase the possibility of better managing infection and decrease treatment failures. For this purpose, we evaluated the antibacterial and antifungal potential of rafoxanide. Notably, 70% (70/100) of bacterial isolates showed multidrug resistance (MDR) patterns, with higher prevalence among human isolates (73.5% [50/68]) than animal ones (62.5% [20/32]). Moreover, 22 fungal isolates (88%) were MDR and were more prevalent among animal (88.9%) than human (87.5%) sources. We observed alarming MDR patterns among bacterial isolates, i.e., Klebsiella pneumoniae (75% [30/40; 8 animal and 22 human]) and Escherichia coli (66% [40/60; 12 animal and 28 human]), and fungal isolates, i.e., Candida albicans (86.7% [13/15; 4 animal and 9 human]) and Aspergillus fumigatus (90% [9/10; 4 animal and 5 human]), that were resistant to at least one agent in three or more different antimicrobial classes. Rafoxanide had antibacterial and antifungal activities, with minimal inhibitory concentration (MICs) ranging from 2 to 128 μg/mL. Rafoxanide at sub-MICs downregulated the mRNA expression of resistance genes, including E. coli and K. pneumoniae blaCTX-M-1, blaTEM-1, blaSHV, MOX, and DHA, C. albicans ERG11, and A. fumigatus cyp51A. We noted the improvement in the activity of β-lactam and antifungal drugs upon combination with rafoxanide. This was apparent in the reduction in the MICs of cefotaxime and fluconazole when these drugs were combined with sub-MIC levels of rafoxanide. There was obvious synergism between rafoxanide and cefotaxime against all E. coli and K. pneumoniae isolates (fractional inhibitory concentration index [FICI] values ≤ 0.5). Accordingly, there was a shift in the patterns of resistance of 16.7% of E. coli and 22.5% of K. pneumoniae isolates to cefotaxime and those of 63.2% of C. albicans and A. fumigatus isolates to fluconazole when the isolates were treated with sub-MICs of rafoxanide. These results were confirmed by in silico and mouse protection assays. Based on the in silico study, one possible explanation for how rafoxanide reduced bacterial resistance is through its inhibitory effects on bacterial and fungal histidine kinase enzymes. In short, rafoxanide exhibited promising results in overcoming bacterial and fungal drug resistance. IMPORTANCE The drug repurposing strategy is an alternative approach to reducing drug development timelines with low cost, especially during outbreaks of disease caused by drug-resistant pathogens. Rafoxanide can disrupt the abilities of bacterial and fungal cells to adapt to stress conditions. The coadministration of antibiotics with rafoxanide can prevent the failure of treatment of both resistant bacteria and fungi, as the resistant pathogens could be made sensitive upon treatment with rafoxanide. From our findings, we anticipate that pharmaceutical companies will be able to utilize new combinations against resistant pathogens.

Tea (Camellia sinensis (L.) Kuntze) as an emerging source of protein and bioactive peptides: A narrative review

Tea residues represent one of the major agricultural wastes that are generated after the processing of tea. They account for 21-28% of crude protein and are often discarded without the extraction of valuable proteins. Due to various bioactivity and functional properties, tea proteins are an excellent alternative to other plant-based proteins for usage as food supplements at a higher dosage. Moreover, their good gelation capacity is ideal for the manufacturing of dairy products, jellies, condensation protein, gelatin gel, bread, etc. The current study is the first to comprehend various tea protein extraction methods and their amino acid profile. The preparation of tea protein bioactive peptides and hydrolysates are summarized. Several functional properties (solubility, foaming capacity, emulsification, water/oil absorption capacity) and bioactivities (antioxidant, antihypertensive, antidiabetic) of tea proteins are emphasized.

Genome-wide analysis revealed the stepwise origin and functional diversification of HSDs from lower to higher plant species

Hydroxysteroid dehydrogenase (HSDs) is an oil-body sterol protein (steroleosin) with an NADP(H) binding domain that belongs to the short-chain dehydrogenase/reductase (SDR) superfamily. There are numerous studies on the characterization of HSDs in plants. However, thus far, the evolutionary differentiation and divergence analysis of these genes remain to be explored. The current study used an integrated method to elucidate the sequential evolution of HSDs in 64 sequenced plant genomes. Analyses were conducted on their origins, distribution, duplication, evolutionary paths, domain functions, motif composition, properties, and cis-elements. Results indicate that except for algae, HSD1 was widely distributed in plant species ranging from lower to higher plants, while HSD5 was restricted to terrestrial plants, and HSD2 was identified in fewer monocots and several dicot plants. Phylogenetic analysis of HSD proteins revealed that monocotyledonous HSD1 in moss and ferns appeared closest to the outgroup, V. carteri HSD-like, M. musculus HSD1, and H. sapiens HSD1. These data support the hypothesis that HSD1 originated in bryophytes and then in non-vascular and vascular plants, followed by HSD5 only in land plants. Gene structure analysis suggests that HSDs in plant species came up with a fixed number of six exons, and the intron phase was primarily 0, 1, 0, 0, and 0. Similarly, duplication analysis revealed that segmental duplications were the main reason for HSDs in plant species. Physicochemical properties suggest that dicotyledonous HSD1s and HSD5s were mainly acidic. The monocotyledonous HSD1s and HSD2s and the dicotyledonous HSD2s, HSD3s, HSD4s, and HSD6s were mainly basic, implying that HSDs in plants may have a variety of functions. Cis-regulatory elements and expression analysis revealed that HSDs in plants might have roles in several abiotic stresses. Due to the high expression of HSD1s and HSD5s in seeds, these HSDs in plants may have roles in fatty acid accumulation and degradation.

Pre and postharvest characteristics of Dahlia pinnata var. pinnata, cav. As affected by SiO2 and CaCO3 nanoparticles under two different planting dates

Agriculture faces many challenges because of climate changes. The nutrients present in nano-sized form improve plant productivity, especially when used at the appropriate planting time. Field experiments were conducted as a factorial experiment for evaluating two planting dates (20th September and 20th October), foliar application with nanoparticles (NPs) including silica nanoparticles (SiO₂-NPs) at 1.5 and 3 mM, calcium carbonate nanoparticles (CaCO₃-NPs) at 5 and 10 mM and distilled water (control) on pre- and post-harvest characteristics of Dahlia pinnata var. pinnata Cav. The results indicate that the interactions during the late planting time (20th October) and exogenous applications of SiO₂-NPs at 1.5 mM or CaCO₃-NPs at 10 mM have improved plant growth including plant height, stem diameter, fresh and dry weights of plant, leaf area, inflorescence diameter, inflorescence stalk length, branches number, tuber numbers, inflorescences number on the plant, and the vase life. At the same time, insignificant differences appeared in the interaction during the planting dates and SiO₂ or CaCO₃ -NPs concentrations on inflorescence stalk diameter, total soluble solids, membrane stability index, maximum increase in fresh weight (FW), and Si and Ca contents. In addition, all exogenous applications of NPs at the late planting time promoted the plant growth characteristics like lignin %, cellulose %, inflorescence water content, change in FW, and total water uptake. Moreover, the controls through the two planting dates recorded the maximum change in water uptake and water loss values. In short, it can be recommended to use SiO₂-NPs at 1.5 mM or CaCO₃-NPs at 10 mM as a foliar application at the late planting time (20th October) for obtaining the optimum quantitative and qualitative parameters of D. pinnata.

Evaluation of flaxseed lignan-enriched extract targeting autophagy, apoptosis, and hedgehog pathways against experimentally induced obesity

Objective

This research investigated secoisolariciresinol diglucoside (SDG) flax extract effects on apoptosis, hedgehog (Hh), autophagy, and the anti-oxidation process in experimentally induced obesity.

Materials and Methods

Forty rats were separated into two sets regarding either receiving a normal balanced diet or a high-fat diet (HFD) and then distributed into four groups: GI: The control group had a regular diet for 12 weeks. GII: animals received a high-fat meal and saline by gastric gavage. GIII: HFD obese rats treated with SDG extract orally (10 mg/kg/b.w.) and 1.18 mg SDG/kg in the diet for 4 weeks GIV: Normal balanced diet rats received SDG extract orally (10 mg/kg/b.w.) and 1.18 mg SDG/kg of chow for 12 weeks in addition to their regular balanced diet.

Results

The administration of SDG extract exhibited a significant drop in body weight, glucose, lipid profile, and leptin compared to the obese group. It also improved the antioxidant levels (lowering the levels of malondialdehyde while increasing the total antioxidant capacity) and anti-inflammatory status (decreasing interleukin-6 and tumor necrosis factor-alpha). SDG extract downregulates the expression of HH genes (protein patched homolog 1, Hh-interacting protein, glioma-associated oncogene homolog 1, and smoothened receptor) in conjunction with the modulation of autophagy genes and apoptotic proteins.

Conclusion

SDG extract showed improved anti-inflammatory and antioxidant status and downregulated the expression of HH genes while modulating autophagy genes and apoptotic proteins among obese rats, suggesting that it may be used to avert and manage obesity and its correlated complications by modulating oxidation, inflammation, autophagy, and apoptosis. Advanced future research on the SDG autophagy pathway to address obesity and its complications is mandatory.

Antifungal Activity of Cell-Free Filtrate of Probiotic Bacteria Lactobacillus rhamnosus ATCC-7469 against Fungal Strains Isolated from a Historical Manuscript

Herein, twelve fungal strains were isolated from a deteriorated historical manuscript dated back to the 18th century. The obtained fungal strains were identified, using the traditional method and ITS sequence analysis, as Cladosporium herbarum (two strains), Aspergillus fumigatus (five strains), A. ustus (one strain), A. flavus (two strains), A. niger (one strain), and Penicillium chrysogenum (one strain). The ability of these fungal strains to degrade the main components of the paper was investigated by their activity to secrete extracellular enzymes including cellulase, amylase, gelatinase, and pectinase. The cell-free filtrate (CFF) ability of the probiotic bacterial strain Lactobacillus rhamnosus ATCC-7469 to inhibit fungal growth was investigated. The metabolic profile of CFF was detected by GC-MS analysis, which confirmed the low and high molecular weight of various active chemical compounds. The safe dose to be used for the biocontrol of fungal growth was selected by investigating the biocompatibility of CFF and two normal cell lines, Wi38 (normal lung tissue) and HFB4 (normal human skin melanocyte). Data showed that the CFF has a cytotoxic effect against the two normal cell lines at high concentrations, with IC₅₀ values of 525.2 ± 9.8 and 329.1 ± 4.2 µg mL^-1 for Wi38 and HFB4, respectively. The antifungal activity showed that the CFF has promising activity against all fungal strains in a concentration-dependent manner. The highest antifungal activity (100%) was recorded for a concentration of 300 µg mL^-1 with a zone of inhibition (ZOI) in the ranges of 21.3 ± 0.6 to 17.7 ± 0.5 mm. At a concentration of 100 µg mL^-1, the activity of CFF remained effective against all fungal strains (100%), but its effectiveness decreased to only inhibit the growth of eight strains (66%) out of the total at 50 µg mL^-1. In general, probiotic bacterial strains containing CFF are safe and can be considered as a potential option for inhibiting the growth of various fungal strains. It is recommended that they be used in the preservation of degraded historical papers.

Green Synthesis of Zinc Oxide Nanoparticles Using an Aqueous Extract of Punica granatum for Antimicrobial and Catalytic Activity

The peel aqueous extract of Punica granatum was utilized to fabricate zinc oxide nanoparticles (ZnO-NPs) as a green approach. The synthesized NPs were characterized by UV-Vis spectroscopy, Fourier transform infrared (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy, which was attached to an energy dispersive X-ray (SEM-EDX). Spherical, well arranged, and crystallographic structures of ZnO-NPs were formed with sizes of 10-45 nm. The biological activities of ZnO-NPs, including antimicrobial and catalytic activity for methylene blue dye, were assessed. Data analysis showed that the antimicrobial activity against pathogenic Gram-positive and Gram-negative bacteria, as well as unicellular fungi, was observed to occur in a dose-dependent manner, displaying varied inhibition zones and low minimum inhibitory concentration (MIC) values in the ranges of 6.25-12.5 µg mL^-1. The degradation efficacy of methylene blue (MB) using ZnO-NPs is dependent on nano-catalyst concentration, contact time, and incubation condition (UV-light emission). The maximum MB degradation percentages of 93.4 ± 0.2% was attained at 20 µg mL^-1 after 210 min in presence of UV-light. Data analysis showed that there is no significant difference between the degradation percentages after 210, 1440, and 1800 min. Moreover, the nano-catalyst showed high stability and efficacy to degrade MB for five cycles with decreasing values of 4%. Overall, P. granatum-based ZnO-NPs are promising tools to inhibit the growth of pathogenic microbes and degradation of MB in the presence of UV-light emission.

Biogenic silver nanoparticles eradicate of Pseudomonas aeruginosa and Methicillin-resistant Staphylococcus aureus (MRSA) isolated from the sputum of COVID-19 patients

In recent investigations, secondary bacterial infections were found to be strongly related to mortality in COVID-19 patients. In addition, Pseudomonas aeruginosa and Methicillin-resistant Staphylococcus aureus (MRSA) bacteria played an important role in the series of bacterial infections that accompany infection in COVID-19. The objective of the present study was to investigate the ability of biosynthesized silver nanoparticles from strawberries (Fragaria ananassa L.) leaf extract without a chemical catalyst to inhibit Gram-negative P. aeruginosa and Gram-positive Staph aureus isolated from COVID-19 patient’s sputum. A wide range of measurements was performed on the synthesized AgNPs, including UV–vis, SEM, TEM, EDX, DLS, ζ -potential, XRD, and FTIR. UV-Visible spectral showed the absorbance at the wavelength 398 nm with an increase in the color intensity of the mixture after 8 h passed at the time of preparation confirming the high stability of the FA-AgNPs in the dark at room temperature. SEM and TEM measurements confirmed AgNPs with size ranges of ∼40-∼50 nm, whereas the DLS study confirmed their average hydrodynamic size as ∼53 nm. Furthermore, Ag NPs. EDX analysis showed the presence of the following elements: oxygen (40.46%), and silver (59.54%). Biosynthesized FA-AgNPs (ζ = −17.5 ± 3.1 mV) showed concentration-dependent antimicrobial activity for 48 h in both pathogenic strains. MTT tests showed concentration-dependent and line-specific effects of FA-AgNPs on cancer MCF-7 and normal liver WRL-68 cell cultures. According to the results, synthetic FA-AgNPs obtained through an environmentally friendly biological process are inexpensive and may inhibit the growth of bacteria isolated from COVID-19 patients.

Mining metagenomes reveals diverse antibiotic biosynthetic genes in uncultured microbial communities

Pathogens resistant to antimicrobials form a significant threat to public health worldwide. Tackling multidrug-resistant pathogens via screening metagenomic libraries has become a common approach for the discovery of new antibiotics from uncultured microorganisms. This study focuses on capturing nonribosomal peptide synthase (NRPS) gene clusters implicated in the synthesis of many natural compounds of industrial relevance. A NRPS PCR assay was used to screen 2976 Escherichia coli clones in a soil metagenomic library to target NRPS genes. DNA extracts from 4 clones were sequenced and subjected to bioinformatic analysis to identify NRPS domains, their phylogeny, and substrate specificity.Successfully, 17 NRPS-positive hits with a biosynthetic potential were identified. DNA sequencing and BLAST analysis confirmed that NRPS protein sequences shared similarities with members of the genus Delftia in the Proteobacteria taxonomic position. Multiple alignment and phylogenetic analysis demonstrated that clones no. 15cd35 and 15cd37 shared low bootstrap values (54%) and were distantly far from close phylogenetic neighbors. Additionally, NRPS domain substrate specificity has no hits with the known ones; hence, they are more likely to use different substrates to produce new diverse antimicrobials. Further analysis confirmed that the NRPS hits resemble several transposon elements from other bacterial taxa, confirming its diversity. We confirmed that the analyses of the soil metagenomic library revealed a diverse set of NRPS related to the genus Delftia. An in-depth understanding of those positive NRPS hits is a crucial step for genetic manipulation of NRPS, shedding light on alternative novel antimicrobial compounds that can be used in drug discovery and hence supports the pharmaceutical sector.

Inductive role of the brown alga Sargassum polycystum on growth and biosynthesis of imperative metabolites and antioxidants of two crop plants

The potential of macroalgae as biostimulants in agriculture was proved worthy. Vicia faba and Helianthus annuus are socioeconomic crops owing to their increasing demand worldwide. In this work, we investigated the energetic role of seed presoaking and irrigation by the brown seaweed, Sargassum polycystum aqueous extract (SAE) on certain germination and growth traits, photosynthetic pigments, carbohydrates, phenolics, flavonoids, and the total antioxidant activity. Compared to the control plants, our consequences revealed that seeds that received the SAE improved all the germination and growth criteria for both crop plants. Furthermore, the SAE significantly increased the carotenoids, total photosynthetic pigments, and total carbohydrates by (14%, 7%, and 41%) for V. faba and (17%, 17%, and 38%) for H. annuus, respectively. Phenolics and flavonoids were significantly induced in Vicia but slightly promoted in Helianthu plants, whereas the total antioxidant activity in both crops non significantly elevated. Even though The NPK contents were significantly stimulated by the SAE in Vicia plants, the effect was different in Helianthus, where only nitrogen content was significantly enhanced, whereas phosphorus and potassium showed little enhancement. Thus, the SAE treatment is one of the superlative sustainable strategies for food, feed, and as excellent plant conditioner.

Evaluation of the Fungicidal Effect of Some Commercial Disinfectant and Sterilizer Agents Formulated as Soluble Liquid against Sclerotium rolfsii Infected Tomato Plant

Globally, root rot disease of tomato plants caused by Sclerotium rolfsii is a severe disease leading to the death of infected plants. The effect of some commercial antiseptics and disinfectant agents, such as chloroxylenol (10%), phenic (10%) and formulated phenol (7%) on the control of root rot pathogen and its impact on growth and chemical constituents of tomato seedlings cv. Castle Rock were investigated in vitro and in vivo. The antifungal activity was measured in vitro following the poisoned food technique at different concentrations of 1000, 2000, 3000 and 4000 µL/L. Disinfectant agents and atrio (80%) were tested in vivo by soaking 20-day-old tomato seedlings in four concentrations of 125, 250, 500 and 1000 µL/100 mL water for 5 min and thereafter planting in soil infested by S. rolfsii. Fresh and dry weight, shoot and root length, and chemical constituents of tomato seedlings infected by S. rolfsii were investigated at 35 days after planting (DAP). Experimental results indicated that chloroxylenol (10%) was the most effective on fungus in vitro, recorded an effective concentration (EC₅₀ = 1347.74 µL/L) followed by phenic (10%) (EC₅₀ = 1370.52 µL/L) and formulated phenol (7%) (EC₅₀ = 1553.59 µL/L). In vivo, atrio (80%) and disinfectant agents at different concentrations significantly (p ≤ 0.05) reduced disease incidence, increased shoot and root lengths and increased dry and fresh weight. Additionally, it significantly increased chlorophyll a, chlorophyll b, total carotenoids, total carbohydrates, total proteins, and total phenols. The highest reduction of root rot incidence and increase tomato growth parameters, as well as chemical compositions, were recorded on tomato seedlings treated with atrio (80%) as well as formulated phenol (7%) at different concentrations, followed by chloroxylenol (10%) at 125 and 250 µL/100 mL, whereas phenic (10%) was found to be the least effective treatment. Therefore, the application of formulated phenol (7%) could be commercially used to control tomato root rot diseases and increase the quality and quantity of tomato plants since it is promising against the pathogen, safe, and less expensive than fungicides.

Postharvest physiology and biochemistry of Valencia orange after coatings with chitosan nanoparticles as edible for green mold protection under room storage conditions

Because of their unique features, nanomaterials have been proposed and have gained acceptance in postharvest applications in fruit. Increasing the storage life and improving the quality of Valencia oranges was investigated using nano-chitosan. A chitosan nanoparticle was prepared by using high-energy ball milling. Chitosan nanoparticles were characterized by Dynamic light scattering, FTIR spectroscopy and Surface morphology by transmission electron microscopy. Fully mature Valencia oranges were harvested and then coated with one of these concentrations (0.2, 0.4, and 0.8% nano-chitosan) and control. The fruits were stored under room storage conditions for 75 days. The quality parameters (fruit weight losses, fruit decay percentage, fruit firmness, total acidity, total soluble solids percentage and T.S.S./acid ratio, ascorbic acid content) were taken in biweekly intervals after 0, 15, 30, 45, 60, and 75 days. Beside the in vitro testing of antifungal activity of chitosan nanoparticles. According to the findings of the two succeeding seasons, the nano-chitosan 0.8% treatment showed the best effects and had the lowest rate of fruit weight loss, fruit deterioration, and T.S.S./acid ratio in comparison to the other treatments in both seasons. Furthermore, the 0.8% nano-chitosan reveled the highest levels of fruit hardness and fruit pulp firmness. Fruit weight loss, fruit deterioration, TSS, and TSS/acid ratio, as well as other metrics, were steadily elevated prior to the storage time. The best results were obtained when Valencia oranges fruits were treated with 0.8% nano-chitosan for 75 days at room temperature.

Valorizing the usage of olive leaves, bioactive compounds, biological activities, and food applications: A comprehensive review

Olive oil production is a significant source of economic profit for Mediterranean nations, accounting for around 98 percent of global output. Olive oil usage has increased dramatically in recent years, owing to its organoleptic characteristics and rising knowledge of its health advantages. The culture of olive trees and the manufacture of industrial and table olive oil produces enormous volumes of solid waste and dark liquid effluents, involving olive leaves, pomace, and olive oil mill wastewaters. These by-products cause an economic issue for manufacturers and pose major environmental concerns. As a result, partial reuse, like other agronomical production wastes, is a goal to be achieved. Because these by-products are high in bioactive chemicals, which, if isolated, might denote components with significant added value for the food, cosmetic, and nutraceutical sectors, indeed, they include significant amounts of beneficial organic acids, carbohydrates, proteins, fibers, and phenolic materials, which are distributed differently between the various wastes depending on the olive oil production method and table olive agronomical techniques. However, the extraction and recovery of bioactive materials from chosen by-products is a significant problem of their reasonable value, and rigorous detection and quantification are required. The primary aims of this review in this context are to outline the vital bioactive chemicals in olive by-products, evaluate the main developments in extraction, purification, and identification, and study their uses in food packaging systems and safety problems.

Trehalose-Induced Regulations in Nutrient Status and Secondary Metabolites of Drought-Stressed Sunflower (Helianthus annuus L.) Plants

Trehalose regulates key physio-biochemical parameters, antioxidants, and the yield of plants exposed to a dry environment. A study was conducted to assess the regulatory roles of exogenously applied trehalose in drought-stressed sunflower plants. Two cultivars of sunflowers (Hysun 33 and FH 598) were subjected to drought stress (60% field capacity) and varying (0, 10, 20, and 30 mM) concentrations of trehalose. The data indicated that water stress significantly reduced the shoot length, root length, total soluble proteins, shoot Ca²⁺, root P, relative water content (RWC), and achene yield per plant. The foliar spray of trehalose was effective at improving plant growth, RWC, total soluble proteins, total soluble sugars, the activities of enzymatic antioxidants, Ca²⁺ (shoot and root), root K⁺, and the yield attributes. Exogenously supplemented trehalose considerably suppressed relative membrane permeability (RMP), but did not alter ascorbic acid, malondialdehyde, the total phenolics, shoot K⁺, or P (shoot and root) in both sunflower cultivars. The cv. Hysun 33 had better ascorbic acid, total soluble sugars, non-reducing sugars, shoot P, and root P than the other cultivar, whereas cv. FH 598 was relatively better at regulating RMP, malondialdehyde, peroxidase, and root Ca²⁺ concentration. Overall, exogenously supplemented trehalose, particularly at 10 mM, was effective at improving the physiochemical parameters and yield of sunflower plants under stress conditions. Therefore, a better performance of sunflower cv. Hysun 33 under drought stress can be suggested as a trehalose-induced enhancement of yield and oxidative defense potential.

Hydrogel Improved Growth and Productive Performance of Mango Trees under Semi-Arid Condition

Nowadays, the production of new mango cultivars is increased in many countries worldwide. The soil application of hydrogel represents a novel approach in the fruit trees industry. This investigation aims to study the effect of adding hydrogel (as soil conditioner) on the growth and yield of Shelly cv. mango trees. The experimental groups were assigned to a control group and three other treated groups, including 250, 500, or 750 g hydrogel∙tree-1. The results demonstrated that all applications of hydrogel composite had higher vegetative growth parameters, yield, and fruit quality characteristics of Shelly cv. mango trees compared to the control. The treatment of 750 g hydrogel∙tree-1 had higher values of vegetative growth parameters such as the leaf area, shoot length and tree canopy volume, compared to the control group and the other treatments. Similarly, higher values for yield and fruit quality were observed in the treatment of 750 g hydrogel∙tree-1. In conclusion, different amounts of hydrogel agent can improve the production and fruit quality of Shelly cv. mango trees in arid and semi-arid conditions in a dose-dependent manner.

Integrative Application of Foliar Yeast Extract and Gibberellic Acid Improves Morpho-Physiological Responses and Nutrient Uptake of Solidago virgaurea Plant in Alkaline Soil

Alkaline soils have fertility issues due to poor physical qualities, which have a negative impact on crop growth and output. Solidago is used in flower arrangements, bouquet filler, and traditional medicine. The possible biological fertilizers’ eco-friendly and cost-effective nature favours farmers because of the vital role in soil productivity and environmental sustainability. A field experiment was performed during two successive seasons to explore the effect of applying yeast extract (YE) at (0, 0.5, 1.0, and 1.5 g/L) and/or gibberellic acid (GA3) at (control, 100, 200, and 300 ppm) on the morpho-physiological parameters, macronutrients, and biochemical constituents of Solidago virgaurea. The results emphasize that YE (1.5 g/L) and/or GA3 (300 ppm) treatments show the highest significant increase in plant growth (i.e., plant height, no. of branches, fresh and dry weight of shoots); photosynthetic efficiency (i.e., chlorophyll (a), chlorophyll (b) and total carotenoids); macronutrient content (i.e., N, P, and K); and biochemical constituents (i.e., total soluble sugars, total phenolic, total flavonoids, and total glycosides). The study results recommend using YE and GA3 in combination at concentrations of 1.5 g/L and 300 ppm, respectively, to improve Solidago production sustainability under alkaline soil conditions.

Folic Acid Confers Tolerance against Salt Stress-Induced Oxidative Damages in Snap Beans through Regulation Growth, Metabolites, Antioxidant Machinery and Gene Expression

Although the effect of folic acid (FA) and its derivatives (folates) have been extensively studied in humans and animals, their effects are still unclear in most plant species, specifically under various abiotic stress conditions. Here, the impact of FA as a foliar application at 0, 0.1, and 0.2 mM was studied on snap bean seedlings grown under non-saline and salinity stress (50 mM NaCl) conditions. The results indicated that under salinity stress, FA-treated plants revealed a significant (p ≤ 0.05) increase in growth parameters (fresh and dry weight of shoot and root). A similar trend was observed in chlorophyll (Chl b), total chlorophyll, carotenoids, leaf relative water content (RWC), proline, free amino acids (FAA), soluble sugars, cell membrane stability index (CMSI), and K, Ca, and K/Na ratio compared to the untreated plants. In contrast, a significant decrease was observed in Na and salinity-induced oxidative damage as indicated by reduced H₂O₂ production (using biochemical and histochemical detection methods) and rate of lipid peroxidation (malondialdehyde; MDA). This enhancement was correlated by increasing the activities of antioxidant enzymes, i.e., superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (G-POX), and ascorbate peroxidase (APX). Gene expression analyses conducted using qRT-PCR demonstrated that genes coding for the Na⁺/H⁺ antiporter protein Salt Overly Sensitive 1 (SOS1), the tonoplast-localized Na⁺/H⁺ antiporter protein (NHX1), and the multifunctional osmotic protective protein (Osmotin) were significantly up-regulated in the FA-treated plants under both saline and non-saline treatments. Generally, treatment with 0.2 mM FA was more potent than 0.1 mM and can be recommended to improve snap bean tolerance to salinity stress.

Effect of Salt Stress and Foliar Application of Salicylic Acid on Morphological, Biochemical, Anatomical, and Productivity Characteristics of Cowpea (Vigna unguiculata L.) Plants

The present study aimed to investigate the impact of salinity on vegetative growth, chemical constituents, and yields of cowpeas (Vigna unguiculata) and the possible benefits of salicylic acid (SA) on these plants after damage from salinity. To achieve these objectives, two pot experiments were carried out at the Faculty of Agriculture, Al-Azhar University, Egypt, during the two growing seasons of 2019 and 2020. The results revealed that salinity significantly decreased, and SA treatment substantially increased the plant height, number of compound leaves, number of internodes per plant, fresh weights of leaves and stems, productivity, photosynthetic pigments content, and concentrations of nitrogen (N), phosphorus (P), and potassium (K) of the cowpea plants compared with the control. The anatomical structure of stems and leaves of the plants were also investigated, and it was found that positive variations in the anatomical structure of the median portion of the main stems and blades of mature foliage leaves were detected in the stressed and SA-treated plants. In conclusion, SA treatment increased the salt stress tolerance of cowpea plants by improving the morphological and physiological attributes of the plants.

Roles of Exogenous α-Lipoic Acid and Cysteine in Mitigation of Drought Stress and Restoration of Grain Quality in Wheat

Cysteine (Cys) and α-lipoic acid (ALA) are naturally occurring antioxidants (sulfur-containing compounds) that can protect plants against a wide spectrum of environmental stresses. However, up to now, there are no conclusive data on their integrative roles in mitigation of drought stress in wheat plants. Here, we studied the influence of ALA at 0.02 mM (grain dipping pre-cultivation treatment) and Cys (25 and 50 ppm as a foliar application) under well watered and deficit irrigation (100% and 70% of recommended dose). The results showed that deficit irrigation markedly caused obvious cellular oxidative damage as indicated by elevating the malondialdehyde (MDA) and hydrogen peroxide content (H₂O₂). Moreover, water stressed plants exhibited multiple changes in physiological metabolism, which affected the quantitative and qualitative variables of grain yield. The enzymatic antioxidants, including superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POX) were improved by Cys application. SOD and APX had the same response when treated with ALA, but CAT and POX did not. Moreover, both studied molecules stimulated chlorophyll (Chl) and osmolytes' biosynthesis. In contrast, the Chl a/b ratio was decreased, while flavonoids were not affected by either of the examined molecules. Interestingly, all above-mentioned changes were associated with an improvement in the scavenging capacity of reactive oxygen species (ROS), leaf relative water content (RWC), grain number, total grain yield, weight of 1000 kernels, gluten index, falling number, and alveographic parameters (P, W, and P/L values). Furthermore, heatmap plot analysis revealed several significant correlations between different studied parameters, which may explore the importance of applied Cys and ALA as effective compounds in wheat cultivation under water deficit conditions.

Biochar and jasmonic acid application attenuates antioxidative systems and improves growth, physiology, nutrient uptake and productivity of faba bean (Vicia faba L.) irrigated with saline water

The effect of foliar treatment with jasmonic acid at 0.5 mM (JA) and biochar (15 ton ha^-1) as a soil amendment for the faba bean (Vicia faba L. Sakha 4) was studied under salinity conditions. Salt stress led to a significant decrease in leaf numbers, leaf areas and plants, chlorophyll content, relative water content, and yield parameters. In contrast, reactive oxygen species, the proline concentration, level of malondialdehyde, and amount of electrolyte leakage were noticeably increased during both seasons under salt levels of 1500 and 3000 ppm sodium chloride (NaCl). Also, enzyme activities (i.e., of superoxide dismutase, catalase, peroxidase, and glutathione reductase) were increased, especially under a high level of salinity stress (3000 ppm). Application of biochar, jasmonic acid, or biochar + jasmonic acid significantly reduced the catalase, superoxide dismutase, and glutathione reductase activities in salt-stressed plants to values approaching those of the control (unstressed) plants, especially under 1500 ppm of NaCl stress. Biochar and jasmonic acid treatments mitigated the damaging effects of salinity and improved the plant status as indicated by the plant height, leaf area, relative water content, and chlorophyll a and b concentrations. Moreover, biochar and jasmonic acid treatments of the salt-stressed plants enhanced plant productivity, number of flowers, number of seeds per plant, and weight of 100 seeds during two successive seasons. Overall, this study suggests that biochar or jasmonic acid treatments might be promising for mitigating the detrimental impact of salt stress on faba beans.

Harnessing Bacterial Endophytes for Promotion of Plant Growth and Biotechnological Applications: An Overview

Endophytic bacteria colonize plants and live inside them for part of or throughout their life without causing any harm or disease to their hosts. The symbiotic relationship improves the physiology, fitness, and metabolite profile of the plants, while the plants provide food and shelter for the bacteria. The bacteria-induced alterations of the plants offer many possibilities for biotechnological, medicinal, and agricultural applications. The endophytes promote plant growth and fitness through the production of phytohormones or biofertilizers, or by alleviating abiotic and biotic stress tolerance. Strengthening of the plant immune system and suppression of disease are associated with the production of novel antibiotics, secondary metabolites, siderophores, and fertilizers such as nitrogenous or other industrially interesting chemical compounds. Endophytic bacteria can be used for phytoremediation of environmental pollutants or the control of fungal diseases by the production of lytic enzymes such as chitinases and cellulases, and their huge host range allows a broad spectrum of applications to agriculturally and pharmaceutically interesting plant species. More recently, endophytic bacteria have also been used to produce nanoparticles for medical and industrial applications. This review highlights the biotechnological possibilities for bacterial endophyte applications and proposes future goals for their application.

Application of soil biofertilizers to a clayey soil contaminated with Sclerotium rolfsii can promote production, protection and nutritive status of Phaseolus vulgaris

Sclerotium rolfsii is a soil-borne fungus that causes big losses in productivity of various plant species including Phaseolus vulgaris L. The objectives of this study were to (1) evaluate the impacts of Sclerotium rolfsii on growth and production of common bean plants, (2) determine the effects of Sclerotium rolfsii on nutritive contents of beans, and (3) test the efficacy of bio-inoculants on suppressing plant infection with Sclerotium rolfsii. To fulfill these objectives, we used a coupled pot and field experimental approaches during two growing seasons. Common beans were inoculated with either arbuscular mycorrhizal fungi (Claroideoglomus etunicatum), Saccharomyces cerevisiae, or Trichoderma viride solely or in different combinations. Non-inoculated plants and fungicide treated ones were considered as reference treatments. Throughout these experiments, minimal amounts of rock phosphate were added during soil preparation for bio-inoculated treatments, while the non-inoculated reference treatments received a full dose of P as calcium superphosphate. Results revealed that all tested bioinoculants significantly raised the activities of plant defense enzymes i.e. chitinase, peroxidase and polyphenoloxidase as compared to non-inoculated control. Likewise, pre-, post- and plant survival percentages significantly increased due to these bio-inoculations. Increased survival percentages were attributed to the concurrent increases in uptake of N, P and Zn nutrients by plants treated with bioinoculants. In this concern, plant nutrients uptake was higher in combined than single bio-inoculant treatments. Moreover, the uptake values of plant nutrients owing to the combined bio-inoculants were higher than the corresponding ones achieved due to fungicide treatment. In conclusion, application of the tested bio-inoculants, especially the combined ones can be considered an eco-friendly approach that not only enhances plants resistance against infection with Sclerotium rolfsii but also improves plant nutritive status.

Comparative Study between Exogenously Applied Plant Growth Hormones versus Metabolites of Microbial Endophytes as Plant Growth-Promoting for Phaseolus vulgaris L

Microbial endophytes organize symbiotic relationships with the host plant, and their excretions contain diverse plant beneficial matter such as phytohormones and bioactive compounds. In the present investigation, six bacterial and four fungal strains were isolated from the common bean (Phaseolus vulgaris L.) root plant, identified using molecular techniques, and their growth-promoting properties were reviewed. All microbial isolates showed varying activities to produce indole-3-acetic acid (IAA) and different hydrolytic enzymes such as amylase, cellulase, protease, pectinase, and xylanase. Six bacterial endophytic isolates displayed phosphate-solubilizing capacity and ammonia production. We conducted a field experiment to evaluate the promotion activity of the metabolites of the most potent endophytic bacterial (Bacillus thuringiensis PB2 and Brevibacillus agri PB5) and fungal (Alternaria sorghi PF2 and, Penicillium commune PF3) strains in comparison to two exogenously applied hormone, IAA, and benzyl adenine (BA), on the growth and biochemical characteristics of the P. vulgaris L. Interestingly, our investigations showed that bacterial and fungal endophytic metabolites surpassed the exogenously applied hormones in increasing the plant biomass, photosynthetic pigments, carbohydrate and protein contents, antioxidant enzyme activity, endogenous hormones and yield traits. Our findings illustrate that the endophyte Brevibacillus agri (PB5) provides high potential as a stimulator for the growth and productivity of common bean plants.

Hydrogen Peroxide Supplementation in Irrigation Water Alleviates Drought Stress and Boosts Growth and Productivity of Potato Plants

The present investigations aim to decipher the beneficial role of hydrogen peroxide-supplemented irrigation in imparting drought tolerance and promotion plant growth and yield of potato plants grown under two different irrigation regimes. Hydrogen peroxide injection (oxygenation) was applied at 0, 300, and 600 ppm through subsurface irrigation regimes on potato performance grown in heavy clay soil. The results indicated that oxygenation of irrigation water boosted the plant′s vegetative growth and productivity, especially at 600 ppm hydrogen peroxide coupled with deficit irrigation. Root respiration, leaf biomass, chlorophyll content, and leaf osmotic status was observed to be improved in the presence of oxygenated irrigation. A similar trend was recorded on macro-elements (nitrogen, phosphorus, potassium and calcium content), proline, and soluble carbohydrates content of leaf along with catalase enzyme activity. Individual tuber weight, tuber number and tuber yield per plant and hectare recorded higher values as responding to oxygenated irrigation (300 and 600 ppm) of water within the optimum irrigation level. While the highest value of water use efficiency (WUE) was obtained by pairing deficit irrigation with 600 ppm oxygenated water. Thus, the present work provides new insights into the importance of oxygenated irrigation in obtaining optimum yield and field performance in potato plants subjected to deficit irrigation in clayey-loamy soils.

Protective Effect of γ-Aminobutyric Acid Against Chilling Stress During Reproductive Stage in Tomato Plants Through Modulation of Sugar Metabolism, Chloroplast Integrity, and Antioxidative Defense Systems

Despite the role of γ-aminobutyric acid (GABA) in plant tolerance to chilling stress having been widely discussed in the seedling stage, very little information is clear regarding its implication in chilling tolerance during the reproductive stage of the plant. Here, we investigated the influence of GABA (1 and 2mM) as a foliar application on tomato plants (Solanum lycopersicum L. cv. Super Marmande) subjected to chilling stress (5°C for 6h/day) for 5 successive days during the flowering stage. The results indicated that applied GABA differentially influenced leaf pigment composition by decreasing the chlorophyll a/b ratio and increasing the anthocyanin relative to total chlorophyll. However, carotenoids were not affected in both GABA-treated and non-treated stressed plants. Root tissues significantly exhibited an increase in thermo-tolerance in GABA-treated plants. Furthermore, applied GABA substantially alleviated the chilling-induced oxidative damage by protecting cell membrane integrity and reducing malondialdehyde (MDA) and H₂O₂. This positive effect of GABA was associated with enhancing the activity of phenylalanine ammonia-lyase (PAL), catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX). Conversely, a downregulation of peroxidase (POX) and polyphenol oxidase (PPO) was observed under chilling stress which indicates its relevance in phenol metabolism. Interesting correlations were obtained between GABA-induced upregulation of sugar metabolism coinciding with altering secondary metabolism, activities of antioxidant enzymes, and maintaining the integrity of plastids' ultrastructure Eventually, applied GABA especially at 2mM improved the fruit yield and could be recommended to mitigate the damage of chilling stress in tomato plants.

Environmental monitoring and prediction of land use and land cover spatio-temporal changes: a case study from El-Omayed Biosphere Reserve, Egypt

Environmental monitoring, using the techniques of remote sensing (RS) and geographic information systems (GIS), allows the production of time efficient, cost-effective, and reliable surveillance and tracking data. Anthropogenic activities appear to be the major trigger of environmental changes, including land use and land cover (LULC) changes, while natural causes have only a minor impact in most cases. The Omayed Biosphere Reserve (OBR) stands as one of the Egyptian protected areas most highly affected by massive unplanned human activities. Thus, the main objective of this study is to determine the spatio-temporal changes in the OBR over a 35-year period using five Landsat (5 ETM images and 8 OLI-TIRS) imageries, with the specific aim of measuring change rates, trends, and magnitudes of LULC changes between 1984 and 2019 with the topography for planning and selection of developmental strategies. The Normalised Difference Vegetation Index is used to identify the vegetation characteristics of different eco-regions and delivers useful information for the study of vegetation health and density. Normalised Difference Built-up Index can likewise be used to quote built-up areas. Unsupervised classification was used to classify LULC patterns. Six classes were recognised: water bodies, coastal sand, urban areas, cultivated land, newly reclaimed areas, and bare soil. Our results reveal that about 33.55% of OBR land cover has transformed into other forms. Cultivated land and urban regions increased by about 143.5 km² and 56.17 km² from 1984 to 2019, respectively. Meanwhile, bare soil decreased to around 209.5 km² in 2019. In conclusion, the conversion of bare soil into urban land and cultivated areas is the major change in the last 35 years in the OBR. Over the past three decades, the OBR has faced radical and imbalanced changes in its natural habitats. Therefore, monitoring and management of LULC changes are crucial for creating links between policy decisions, regulatory actions, and following LULC activities in the future, especially as many potential risks still exist in the remaining regions of the OBR.

Influence of Maternal Habitat on Salt Tolerance During Germination and Growth in Zygophyllum coccineum

Zygophyllum coccineum is a facultative halophyte widely distributed in desert wadis and coastal areas in Egypt. Here, we investigated the influences of maternal habitat on tolerance to salt stress during germination and seedling growth under salinity (0, 100, 200, 400 mM NaCl) of three populations of Z. coccineum from a saline habitat (Manzala coast) and non-saline habitats (Wadi Houf and Wadi Asyuti). In all populations, seed germination started within two days in distilled water but germination indices were reduced significantly with salt level increase. Germination percentage was not significantly greater for seeds from non-saline habitats than for those from the saline habitat under moderate salinity (100, 200 mM NaCl), but only seeds from the saline habitat were able to germinate under high salt stress (400 mM NaCl). Germination recovery was greater for seeds from the saline habitat compared to non-saline populations. At the seedling level, the Manzala population showed the lowest inhibition of shoot length and leaf area under salinity (200 and 400 mM NaCl) compared to non-saline habitats. In the same context, the Manzala population had the maximum chlorophyll a content, superoxide dismutase and esterase activities under salinity compared to non-saline populations, but salinity had a non-significant effect on chlorophyll b between the three populations. Carotenoids were enhanced with the increase of salt levels in all populations. These results suggest the salt tolerance of Manzala population is derived from maternal salinity and adaptive plasticity of this species may play an important role in the wide distribution of Z. coccineum.

Influence of Polyethylene Glycol on Leaf Anatomy, Stomatal Behavior, Water Loss, and Some Physiological Traits of Date Palm Plantlets Grown In Vitro and Ex Vitro

Few reports explain the mechanism of PEG action on stomatal behavior and anatomical structure and analyze the photosynthetic pigments of in vitro date palm plantlets for better tolerance to ex vitro exposure. The main challenge for in vitro micropropagation of date palm techniques remains restricted to high survival rates and vigorous growth after ex vitro transplantation. In vitro hardening is induced by Polyethylene glycol PEG (0.0, 10, 20, 30 g L⁻¹) for 4 weeks. Leaf anatomy, stomatal behavior, water loss %, photosynthetic pigments, and reducing sugars were examined in date palm plantlets (Phoenix dactylifera L.) cv. (Sewi) after 4 weeks from in vitro PEG treatment and after 4 weeks from ex vitro transplanting to the greenhouse. Leaf anatomy and the surface ultrastructure of in vitro untreated leaves showed a thin cuticle layer, wide opened malfunctioning stomata, and abnormal leaf anatomy. Furthermore, addition of PEG resulted in increasing cuticle thickness, epicuticular wax depositions, and plastids density, improving the stomatal ability to close and decreasing the stomatal aperture length while reducing the substomatal chambers and intercellular spaces in the mesophyll. As a result, a significant reduction in water loss % was observed in both in vitro and ex vitro PEG treated leaves as compared to untreated ones, which exhibited rapid wilting when exposed to low humidity for 4 h. PEG application significantly increased Chlorophylls a, b and carotenoids concentrations, especially 10, 20 g L⁻¹ treatments, which were sequentially reflected in increasing the reducing sugar concentration. However, leaves of plantlets treated with PEG at 30 g L⁻¹ became yellow and had necrosis ends with death. In vitro hardening by 20 g L⁻¹ PEG increased the survival rate of plantlets to 90% after ex vitro transfer compared to 63% recorded for the untreated plantlets. Therefore, this application provides normal date palm plantlets developed faster and enhances survival after ex vitro transfer.

Methicillin-Resistant Staphylococcus aureus (MRSA): One Health Perspective Approach to the Bacterium Epidemiology, Virulence Factors, Antibiotic-Resistance, and Zoonotic Impact

Methicillin-resistant Staphylococcus aureus (MRSA) is a major human pathogen and a historically emergent zoonotic pathogen with public health and veterinary importance. In humans, MRSA commonly causes severe infectious diseases, including food poisoning, pyogenic endocarditis, suppurative pneumonia, otitis media, osteomyelitis, and pyogenic infections of the skin, soft tissues. In the horse, MRSA could cause a localized purulent infection and botryomycosis; in cattle and ewe, localized pyogenic infection and severe acute mastitis with marked toxemia; in sheep, abscess disease resembles caseous lymphadenitis caused by anaerobic strains; in dogs and cats, pustular dermatitis and food poisoning; in pig, exudative epidermatitis “greasy pig disease; in birds, MRSA causes bumble-foot. The methicillin resistance could be determined by PCR-based detection of the mecA gene as well as resistance to cefoxitin. In Egypt, MRSA is one of the important occasions of subclinical and clinical bovine mastitis, and the prevalence of MRSA varies by geographical region. In this review, we are trying to illustrate variable data about the host susceptibility, diseases, epidemiology, virulence factors, antibiotic resistance, treatment, and control of MRSA infection.

Melatonin-Induced Water Stress Tolerance in Plants: Recent Advances

Water stress (drought and waterlogging) is severe abiotic stress to plant growth and development. Melatonin, a bioactive plant hormone, has been widely tested in drought situations in diverse plant species, while few studies on the role of melatonin in waterlogging stress conditions have been published. In the current review, we analyze the biostimulatory functions of melatonin on plants under both drought and waterlogging stresses. Melatonin controls the levels of reactive oxygen and nitrogen species and positively changes the molecular defense to improve plant tolerance against water stress. Moreover, the crosstalk of melatonin and other phytohormones is a key element of plant survival under drought stress, while this relationship needs further investigation under waterlogging stress. In this review, we draw the complete story of water stress on both sides-drought and waterlogging-through discussing the previous critical studies under both conditions. Moreover, we suggest several research directions, especially for waterlogging, which remains a big and vague piece of the melatonin and water stress puzzle.

Regulation of Agronomic Traits, Nutrient Uptake, Osmolytes and Antioxidants of Maize as Influenced by Exogenous Potassium Silicate under Deficit Irrigation and Semiarid Conditions

Understanding the link between the protective role of potassium silicate (K2SiO3) against water shortage and the eventual grain yield of maize plants is still limited under semiarid conditions. Therefore, in this study, we provide insights into the underlying metabolic responses, mineral nutrients uptake and some nonenzymatic and enzymatic antioxidants that may differ in maize plants as influenced by the foliar application of K2SiO3 (0, 1 and 2 mM) under three drip irrigation regimes (100, 75 and 50% of water requirements). Our results indicated that, generally, plants were affected by both moderate and severe deficit irrigation levels. Deficit irrigation decreased shoot dry weight, root dry weight, leaf area index (LAI), relative water content (RWC), N, P, K, Ca, Fe, Zn, carotenoids, grain yield and its parameters, while root/shoot ratio, malondialdehyde (MDA), proline, soluble sugars, ascorbic acid, soluble phenols, peroxidase (POD), catalase (CAT), polyphenol oxidase (PPO), and ascorbate peroxidase (APX) were improved. The foliar applications of K2SiO3 relatively alleviated water stress-induced damage. In this respect, the treatment of 2 mM K2SiO3 was more effective than others and could be recommended to mitigate the effect of deficit irrigation on maize plants. Moreover, correlation analysis revealed a close link between yield and the most studied traits.

Oxidative Stress Responses of Some Endemic Plants to High Altitudes by Intensifying Antioxidants and Secondary Metabolites Content

Most endemic plant species have limited altitudinal ranges. At higher altitudes, they are subjected to various environmental stresses. However, these plants use unique defense mechanisms at high altitudes as a convenient survival strategy. The changes in antioxidant defense system and accumulation of different secondary metabolites (SMs) were investigated as depending on altitude in five endemic endangered species (Nepeta septemcrenata, Origanum syriacum subsp. Sinaicum, Phlomis aurea, Rosa arabica, and Silene schimperiana) naturally growing in Saint Katherine protectorate (SKP). Leaves were collected from different sites between 1600 and 2200 m above sea level to assess the biochemical and physiological variations in response to high altitudes. At higher altitudes, the soil pH and micronutrient soil content decreased, which can be attributed to lower mineralization processes at lower pH. Total phenols, ascorbic acid, proline, flavonoids, and tannins increased in response to different altitudes. SMs progressively increased in the studied species, associated with a significant decrease in the levels of antioxidant enzyme activity. R. arabica, as the most threatened plant, showed the maximum response compared with other species. There was an increase in photosynthetic pigments, which was attained via the increase in chlorophyll a, chlorophyll b, and carotenoid contents. There was a significant increase in total soluble sugars and total soluble protein content in response to different altitudes. SDS-PAGE of leaf proteins showed alteration in the protein profile between different species and the same species grown at a different altitude. These five species can adapt to high-altitude habitats by various physiological mechanisms, which can provide a theoretical basis for the future conservation of these endangered endemic species in SKP.

Influence of phosphorus on copper phytoextraction via modulating cellular organelles in two jute (Corchorus capsularis L.) varieties grown in a copper mining soil of Hubei Province, China

Soil in mining areas is typically highly contaminated with heavy metals and lack essential nutrients for plants. Phosphorus reduces oxidative stress, improves plant growth, composition, and cellular structure, as well as facilitates the phytoremediation potential of fibrous crop plant species. In this study, we investigated two jute (Corchorus capsularis) varieties HongTieGuXuan and GuBaChangJia cultivated in copper (Cu)-contaminated soil (2221 mg kg^-1), under different applications of phosphorus (0, 30, 60, and 120 kg ha^-1) at both anatomical and physiological levels. At the same Cu concentration, the tolerance index of HongTieGuXuan was higher than that of GuBaChangJia, indicating that HongTieGuXuan may be more tolerant to Cu stress. Although the normal concentration of P (60 kg ha^-1) in the soil improved plant growth, biomass, chlorophyll content, fibre yield and quality, and gaseous exchange attributes. However, high concentration of P (120 kg ha^-1) was toxic to both jute varieties affected morphological and physiological attributes of the plants under same level of Cu. Moreover, Cu toxicity increased the oxidative stress in the leaves of both jute varieties was overcome by the activities of antioxidant enzymes. Furthermore, the high concentration of Cu altered the ultrastructure of chloroplasts, plastoglobuli, mitochondria, and many other cellular organelles in both jute varieties. Thus, phytoextraction of Cu by both jute varieties increased with the increase in P application in the Cu-contaminated soil. This suggests that P application enhanced the phytoremediation potential jute plants and can be cultivated as fibrous crop in Cu-contaminated sites.

Rhizophagus irregularis and Rhizoctonia solani Differentially Elicit Systemic Transcriptional Expression of Polyphenol Biosynthetic Pathways Genes in Sunflower

Plant roots are exposed to penetration by different biotrophic and necrotrophic fungi. However, plant immune responses vary, depending on the root-penetrating fungus. Using qRT-PCR, changes over time in the systemic transcriptional expression of the polyphenol biosynthesis-related genes were investigated in sunflower plants in response to colonization with Rhizophagus irregularis and/or infection with Rhizoctonia solani. The results demonstrated that both fungi systemically induced the transcriptional expression of most of the addressed genes at varying degrees. However, the inducing effect differed according to the treatment type, plant organ, targeted gene, and time stage. The inducing effect of R. irregularis was more prevalent than R. solani in the early stages. In general, the dual treatment showed a superior inducing effect over the single treatments at most of the time. The hierarchical clustering analysis showed that cinnamate-4-hydroxylase was the master expressed gene along the studied time period. The cell wall lignification was the main plant-defensive-mechanism induced. In addition, accumulations of chlorogenic acid, flavonoids, and anthocyanins were also triggered. Moreover, colonization with R. irregularis improved the plant growth and reduced the disease severity. We can conclude that the proactive, rather than curative, colonization with R. irregularis is of great importance, owing to their protective and growth-promoting roles, even if no infection occurred.

Brassinosteroid seed priming with nitrogen supplementation improves salt tolerance in soybean

This study was conducted to evaluate the influence of brassinosteroid (24-epibrassinolide, EBL) seed priming and optimal nitrogen (N) supply in improving salt tolerance in soybean. The experimental treatments were (a) control (nutrient solution without N and without EBL priming), (b) nutrient solution without N and EBL seed priming, (c) N supplemented nutrient solution without EBL priming and (d) EBL seed priming + N supplemented nutrient solution under optimal (0 mM NaCl) and salt stress (0 mM NaCl) conditions. Salt stress caused significant reduction in growth and biomass accumulation of soybean. However, EBL seed priming and application of N improved the soybean performance under optimal and salt stress conditions. In this regard, treatments receiving both EBL and N were more effective. EBL priming and N, alone and in combination, triggered the accumulation of osmolytes including proline, glycine betaine and sugars resulting in better photo-protection through maintenance of tissue water content. Antioxidant activity and osmolyte accumulation significantly increased due to combined treatment of N and EBL under normal as well as salt stress conditions. In conclusion, salt stress caused reduction in growth and biomass soybean due to oxidative damage and osmotic stresses. However, soybean performance was improved by seed priming with EBL. Supplementation of N further improved the effectiveness of EBL treatment in improving salt tolerance in soybean.

Use of Nitric Oxide and Hydrogen Peroxide for Better Yield of Wheat (Triticum aestivum L.) under Water Deficit Conditions: Growth, Osmoregulation, and Antioxidative Defense Mechanism

The present experiment was carried out to study the influences of exogenously-applied nitric oxide (NO) donor sodium nitroprusside (SNP) and hydrogen peroxide (H2O2) as seed primers on growth and yield in relation with different physio-biochemical parameters, antioxidant activities, and osmolyte accumulation in wheat plants grown under control (100% field capacity) and water stress (60% field capacity) conditions. During soaking, the seeds were covered and kept in completely dark. Drought stress markedly reduced the plant growth, grain yield, leaf photosynthetic pigments, total phenolic content (TPC), total soluble proteins (TSP), leaf water potential (Ψw), leaf turgor potential (Ψp), osmotic potential (Ψs), and leaf relative water content (LRWC), while it increased the activities of enzymatic antioxidants and the accumulation of leaf ascorbic acid (AsA), proline (Pro), glycine betaine (GB), malondialdehyde (MDA), and H2O2. However, seed priming with SNP and H2O2 alone and in combination mitigated the deleterious effects of water stress on growth and yield by improving the Ψw, Ψs, Ψp, photosynthetic pigments, osmolytes accumulation (GB and Pro), TSP, and the antioxidative defense mechanism. Furthermore, the application of NO and H2O2 as seed primers also reduced the accumulation of H2O2 and MDA contents. The effectiveness was treatment-specific and the combined application was also found to be effective. The results revealed that exogenous application of NO and H2O2 was effective in increasing the tolerance of wheat plants under drought stress in terms of growth and grain yield by regulating plant-water relations, the antioxidative defense mechanism, and accumulation of osmolytes, and by reducing the membrane lipid peroxidation.

Egg Yolk IgY: A Novel Trend of Feed Additives to Limit Drugs and to Improve Poultry Meat Quality

Drugs that are commonly used in poultry farms can potentially cause a detrimental effect on meat consumers as a result of chemical residues. Therefore, seeking a natural alternative is crucial for the health of the consumers. The egg yolk immunoglobulin Y (IgY) is a promising natural replacement for antibiotics in the broilers' diet. There is a scarce focus on the influence of probiotics and IgY on the quality and the nutritive values of broiler meat and whether it can efficiently displace the anti-microbial power of antibiotics. Herein we used 40 Ross chicks (1.2 ± 0.43 days old) and separated them into four groups with variant feed additives (basal diet "control," probiotic, IgY, and probiotic + IgY). Our findings showed that the combination of probiotic and IgY supplementation enhanced the carcass quality traits and decreased the pH values that could retard spoilage due to bacteria and improve shelf life and meat quality. The same group also achieved a significant reduction in thiobarbituric acid value, indicating an improvement of meat quality. Moreover, color, shear force, water holding capacity, and cooking loss were most acceptable in broiler meat supplemented with IgY, which confirmed the highest carcass quality. Notably, the weight gain in the combination group has been greatly increased. Also, the protein percentage was the highest (22.26 ± 0.29, P < 0.001) in this combined supplementation group, which revealed the highest nutritive values. Staphylococcus aureus and Escherichia coli could not be detected in the meat of the probiotics group and/or in the combined treatment group. Interestingly, the IgY group showed an evidence of the killing power (log colony-forming units per milliliter) of S. aureus and Listeria monocytogenes at 1,500 μg/ml. Our findings, in vitro as well as in vivo, revealed that the combination group had antimicrobial bioactivity and enhanced the chickens' immunity. Therefore, IgY, a novel trend of feed additives, can be used to limit drugs. Additionally, the mortality percentage recorded was zero in all groups that received feed supplementation, while the combination group reached the best financial advantages. We concluded that feeding IgY powder with probiotic is a frontier to improve the productivity, immunity, and meat quality of broilers.

Melatonin and Its Protective Role against Biotic Stress Impacts on Plants

Biotic stress causes immense damage to agricultural products worldwide and raises the risk of hunger in many areas. Plants themselves tolerate biotic stresses via several pathways, including pathogen-associated molecular patterns (PAMPs), which trigger immunity and plant resistance (R) proteins. On the other hand, humans use several non-ecofriendly methods to control biotic stresses, such as chemical applications. Compared with chemical control, melatonin is an ecofriendly compound that is an economical alternative strategy which can be used to protect animals and plants from attacks via pathogens. In plants, the bactericidal capacity of melatonin was verified against Mycobacterium tuberculosis, as well as multidrug-resistant Gram-negative and -positive bacteria under in vitro conditions. Regarding plant-bacteria interaction, melatonin has presented effective antibacterial activities against phytobacterial pathogens. In plant-fungi interaction models, melatonin was found to play a key role in plant resistance to Botrytis cinerea, to increase fungicide susceptibility, and to reduce the stress tolerance of Phytophthora infestans. In plant-virus interaction models, melatonin not only efficiently eradicated apple stem grooving virus (ASGV) from apple shoots in vitro (making it useful for the production of virus-free plants) but also reduced tobacco mosaic virus (TMV) viral RNA and virus concentration in infected Nicotiana glutinosa and Solanum lycopersicum seedlings. Indeed, melatonin has unique advantages in plant growth regulation and increasing plant resistance effectiveness against different forms of biotic and abiotic stress. Although considerable work has been done regarding the role of melatonin in plant tolerance to abiotic stresses, its role in biotic stress remains unclear and requires clarification. In our review, we summarize the work that has been accomplished so far; highlight melatonin's function in plant tolerance to pathogens such as bacteria, viruses, and fungi; and determine the direction required for future studies on this topic.

Changes in Ecophysiology, Osmolytes, and Secondary Metabolites of the Medicinal Plants of Mentha piperita and Catharanthus roseus Subjected to Drought and Heat Stress

Global warming contributes to higher temperatures and reduces rainfall for most areas worldwide. The concurrent incidence of extreme temperature and water shortage lead to temperature stress damage in plants. Seeking to imitate a more natural field situation and to figure out responses of specific stresses with regard to their combination, we investigated physiological, biochemical, and metabolomic variations following drought and heat stress imposition (alone and combined) and recovery, using Mentha piperita and Catharanthus roseus plants. Plants were exposed to drought and/or heat stress (35 °C) for seven and fourteen days. Plant height and weight (both fresh and dry weight) were significantly decreased by stress, and the effects more pronounced with a combined heat and drought treatment. Drought and/or heat stress triggered the accumulation of osmolytes (proline, sugars, glycine betaine, and sugar alcohols including inositol and mannitol), with maximum accumulation in response to the combined stress. Total phenol, flavonoid, and saponin contents decreased in response to drought and/or heat stress at seven and fourteen days; however, levels of other secondary metabolites, including tannins, terpenoids, and alkaloids, increased under stress in both plants, with maximal accumulation under the combined heat/drought stress. Extracts from leaves of both species significantly inhibited the growth of pathogenic fungi and bacteria, as well as two human cancer cell lines. Drought and heat stress significantly reduced the antimicrobial and anticancer activities of plants. The increased accumulation of secondary metabolites observed in response to drought and/or heat stress suggests that imposition of abiotic stress may be a strategy for increasing the content of the therapeutic secondary metabolites associated with these plants.

Exogenous Nitric Oxide Mitigates Nickel-Induced Oxidative Damage in Eggplant by Upregulating Antioxidants, Osmolyte Metabolism, and Glyoxalase Systems

Nitric oxide (NO) at optimal levels is considered beneficial to plant functioning. The present study was carried out to investigate the role of exogenously applied NO (100 and 150 µM sodium nitropurusside, SNP) in amelioration of nickel (Ni)-mediated oxidative effects in eggplant. Ni stress declined growth and biomass production, relative water content (RWC), and chlorophyll pigment synthesis, thereby affecting the photosynthetic efficiency. Exogenously applied SNP proved beneficial in mitigating the Ni-mediated growth restrictions. NO-treated seedlings exhibited improved photosynthesis, stomatal conductance, and chlorophyll content with the effect of being apparent at lower concentration (100 µM SNP). SNP upregulated the antioxidant system mitigating the oxidative damage on membranes due to Ni stress. The activity of superoxide dismutase, catalase, glutathione S-transferase, ascorbate peroxidase, and glutathione reductase was upregulated due to SNP which also increased the ascorbate and reduced glutathione content. SNP-supplied seedlings also showed higher proline and glycine betaine accumulation, thereby improving RWC and antioxidant system. Glyoxalase I activity was induced due to SNP application declining the accumulation of methylglyoxal. NO-mediated mitigation of Ni toxicity was confirmed using NO scavenger (PTIO, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), which reversed the influence of SNP almost entirely on the parameters studied. Uptake of nitrogen (N), potassium (K), and calcium (Ca) was increased due to SNP application and Ni was reduced significantly. Therefore, this study revealed the efficiency of exogenous SNP in enhancing Ni stress tolerance through upregulating antioxidant and glyoxalase systems.

Common ragweed (Ambrosia artemisiifolia L.): allergenicity and molecular characterization of pollen after plant exposure to elevated NO2

Ragweed pollen is the main cause of allergenic diseases in Northern America, and the weed has become a spreading neophyte in Europe. Climate change and air pollution are speculated to affect the allergenic potential of pollen. The objective of this study was to investigate the effects of NO2 , a major air pollutant, under controlled conditions, on the allergenicity of ragweed pollen. Ragweed was exposed to different levels of NO2 throughout the entire growing season, and its pollen further analysed. Spectroscopic analysis showed increased outer cell wall polymers and decreased amounts of pectin. Proteome studies using two-dimensional difference gel electrophoresis and liquid chromatography-tandem mass spectrometry indicated increased amounts of several Amb a 1 isoforms and of another allergen with great homology to enolase Hev b 9 from rubber tree. Analysis of protein S-nitrosylation identified nitrosylated proteins in pollen from both conditions, including Amb a 1 isoforms. However, elevated NO2 significantly enhanced the overall nitrosylation. Finally, we demonstrated increased overall pollen allergenicity by immunoblotting using ragweed antisera, showing a significantly higher allergenicity for Amb a 1. The data highlight a direct influence of elevated NO2 on the increased allergenicity of ragweed pollen and a direct correlation with an increased risk for human health.