(ToMV) is one of the economically damageable
infecting the tomato in Egypt that has caused significant losses. It is therefore of great interest to trigger systemic resistance to ToMV. In this ...endeavor, we aimed to explore the capacity of ZnO-NPs (zinc oxide nanoparticles) to trigger tomato plant resistance against ToMV. Effects of ZnO-NPs on tomato (
L.) growth indices and antioxidant defense system activity under ToMV stress were investigated. Noticeably that treatment with ZnO-NPs showed remarkably increased growth indices, photosynthetic attributes, and enzymatic and non-enzymatic antioxidants compared to the challenge control. Interestingly, oxidative damage caused by ToMV was reduced by reducing malondialdehyde, H
O
, and O
levels. Overall, ZnO-NPs offer a safe and economic antiviral agent against ToMV.
(CMV) is a deadly plant virus that results in crop-yield losses with serious economic consequences. In recent years, environmentally friendly components have been developed to manage crop diseases as ...alternatives to chemical pesticides, including the use of natural compounds such as glycine betaine (GB) and chitosan (CHT), either alone or in combination. In the present study, the leaves of the cucumber plants were foliar-sprayed with GB and CHT-either alone or in combination-to evaluate their ability to induce resistance against CMV. The results showed a significant reduction in disease severity and CMV accumulation in plants treated with GB and CHT, either alone or in combination, compared to untreated plants (challenge control). In every treatment, growth indices, leaf chlorophylls content, phytohormones (i.e., indole acetic acid, gibberellic acid, salicylic acid and jasmonic acid), endogenous osmoprotectants (i.e., proline, soluble sugars and glycine betaine), non-enzymatic antioxidants (i.e., ascorbic acid, glutathione and phenols) and enzymatic antioxidants (i.e., superoxide dismutase, peroxidase, polyphenol oxidase, catalase, lipoxygenase, ascorbate peroxidase, glutathione reductase, chitinase and β-1,3 glucanase) of virus-infected plants were significantly increased. On the other hand, malondialdehyde and abscisic acid contents have been significantly reduced. Based on a gene expression study, all treated plants exhibited increased expression levels of some regulatory defense genes such as
and
. In conclusion, the combination of GB and CHT is the most effective treatment in alleviated virus infection. To our knowledge, this is the first report to demonstrate the induction of systemic resistance against CMV by using GB.
During the spring of 2019, distinct virus-like symptoms were observed in the Kafr El-Sheikh Governorate in Egypt in naturally infected eggplants. Leaves of affected plants showed interveinal leaf ...chlorosis, net yellow, chlorotic sectors, mottling, blisters, vein enation, necrotic intervention, and narrowing symptoms. The
(AMV) was suspected of to be involved in this disease. Forty plant samples from symptomatic eggplants and 10 leaf samples with no symptoms were collected. The samples were tested by double antibody sandwich ELISA (DAS-ELISA) using AMV-IgG. Six of the 40 symptomatic leaf samples tested positive for AMV, while, DAS-ELISA found no AMV in the 10 leaf samples without symptoms. The AMV Egyptian isolate (AMV-Eggplant-EG) was biologically isolated from the six positive samples tested by DAS-ELISA and from the similar local lesions induced on
and then re-inoculated in healthy
as a source of AMV-Eggplant-EG and confirmed by DAS-ELISA.
(RT-PCR) assay with a pair of primers specific for coat protein (CP) encoding RNA 3 of AMV yielded an amplicon of 666 bp from infected plants of
with AMV-Eggplant-EG. The amplified PCR product was cloned and sequenced. Analysis of the AMV-Eggplant-EG sequence revealed 666 nucleotides (nt) of the complete CP gene (translating 221 amino acid (aa) residues). Analysis of phylogeny for nt and deduced aa sequences of the CP gene using the maximum parsimony method clustered AMV-Eggplant-EG in the lineage of Egyptian isolates (shark-EG, mans-EG, CP2-EG, and FRE-EG) with a high bootstrap value of 88% and 92%, respectively. In addition to molecular studies, melatonin (MTL) and salicylic acid (SA) (100 μM) were used to increase the resistance of eggplant to AMV- infection. Foliar spray with MLT and SA caused a significant increase in the morphological criteria (shoot, root length, number of leaves, leaf area, and leaf biomass), chlorophyll and carotenoid content, antioxidant enzymes, and gene expression of some enzymes compared to the infected plants. On the other hand, treatment with MLT and SA reduced the oxidative damage caused by AMV through the reduction of hydrogen peroxide, superoxide anions, hydroxyl radicals, and malondialdehyde. In conclusion, MLT and SA are eco-friendly compounds and can be used as antiviral compounds.
Cadmium (Cd) and nickel (Ni) are two of the most toxic metals, wreaking havoc on human health and agricultural output. Furthermore, high levels of Cd and Ni in the soil environment, particularly in ...the root zone, may slow plant development, resulting in lower plant biomass. On the other hand, endophytic bacteria offer great promise for reducing Cd and Ni. Moreover, they boost plants’ resistance to heavy metal stress. Different bacterium strains were isolated from tomato roots. These isolates were identified as Micrococcus luteus and Enterobacter cloacae using 16SrDNA and were utilized to investigate their involvement in mitigating the detrimental effects of heavy metal stress. The two bacterial strains can solubilize phosphorus and create phytohormones as well as siderophores. Therefore, the objective of this study was to see how endophytic bacteria (Micrococcus luteus and Enterobactercloacae) affected the mitigation of stress from Cd and Ni in tomato plants grown in 50 μM Cd or Ni-contaminated soil. According to the findings, Cd and Ni considerably lowered growth, biomass, chlorophyll (Chl) content, and photosynthetic properties. Furthermore, the content of proline, phenol, malondialdehyde (MDA), H2O2, OH, O2, the antioxidant defense system, and heavy metal (HM) contents were significantly raised under HM-stress conditions. However, endophytic bacteria greatly improved the resistance of tomato plants to HM stress by boosting enzymatic antioxidant defenses (i.e., catalase, peroxidase, superoxide dismutase, glutathione reductase, ascorbate peroxidase, lipoxygenase activity, and nitrate reductase), antioxidant, non-enzymatic defenses, and osmolyte substances such as proline, mineral content, and specific regulatory defense genes. Moreover, the plants treated had a higher value for bioconcentration factor (BCF) and translocation factor (TF) due to more extensive loss of Cd and Ni content from the soil. To summarize, the promotion of endophytic bacterium-induced HM resistance in tomato plants is essentially dependent on the influence of endophytic bacteria on antioxidant capacity and osmoregulation.
Bean yellow mosaic virus (BYMV) is the main cause of the mosaic and malformation of many plants, worldwide. Thus, the triggering of plant systemic resistance against BYMV is of great interest. In ...this endeavor, we aimed to explore the capacity of new carboxymethyl chitosan-titania nanobiocomposites (NBCs, NBC1,2) to trigger faba bean plants resistance against BYMV. Effects of NBCs on faba bean (Vicia faba L.) disease severity (DS), growth parameters, and antioxidant defense system activity were investigated under BYMV stress. Noticeably that the DS in NBCs-treated faba bean was significantly reduced compared to untreated plants. Moreover, treatment with NBCs was remarkably increased growth indices, photosynthetic pigments, membrane stability index, and relative water content compared to challenge control. Additionally, enzymatic and non-enzymatic antioxidants and total soluble protein were significantly increased. Contrary, electrolyte leakage, hydrogen peroxide, and lipid peroxidation were reduced. Interestingly that NBC1 has higher efficacy than NBC2 in triggering plant immune-system against BYMV as indicated from DS percentage (DS = 10.66% and 19.33% in case of plants treated with NBC1 and NBC2, respectively). This could be attributed to the higher content of TNPs in NBC1 (21.58%) as compared to NBC2 (14.32%). Overall, NBCs offer safe and economic antiviral agents against BYMV.
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In the current study, zinc oxide nanoparticles (ZnO-NP) were prepared using extracellular extracts of Aspergillus niger. Hence, the morphological structure, optical, and surface features of the ...synthesized nanoparticles were studied by X-ray diffraction, transmission electron microscopy, ultraviolet-visible and infrared absorption by Fourier transform. Use dynamic light scattering and zeta potential measurements to assess colloidal stability. The mean size of the synthetic particles is approximately 20 ± 5 nm and they have a hexagonal crystal structure. In addition, the prepared nanoparticles have strong light absorption in the ultraviolet region of λ = 265 and 370 nm. To achieve the goal of this study, the efficiency of ZnO-NP was determined as an antibacterial and antifungal against different bacterial and fungal strains. It was found that ZnO-NP showed significant antibacterial activity, where the inhibition zones were varied from 21 to 35mm in diameter against six bacterial species (i.e. K. pneumoniae, E. coli, A. baumannii, P. aeruginosa, S. aureus, and S. haemolyticus). In such a case, the minimal inhibitory concentration of zinc oxide nanoparticles against bacterial strains were 50, 12.5, 12.5, 50, 12.5, and 12.5μg/ml for K. pneumoniae, E. coli, A. baumannii, P. aeruginosa, S. aureus, and S. haemolyticus, respectively. Furthermore, ZnO-NP exhibits an antifungal behaviour against four fungal species (i.e., A. niger, P. marneffei, C. glabrata, and C. parapsilosis) with inhibition zone from 18 to 35mm in diameter. Whereas, the MICs for fungal isolates were 12.5μg/ml except A. niger was at 25μg/ml. Wi-38 cells were treated with ZnO-NPs exhibited different levels of cytotoxicity dependent upon the concentration of ZnO NPs using the MTT assay with IC50~800.42. Therefore, the present study introduces a facile and cost-effective extracellular green-synthesis of ZnO-NP to be used as antimicrobial and anticancer agents.
Background
Coconut oil, a natural component abundant in terpenoids, possesses various physiological functions. The global concern over the spread of viral infections and antimicrobial-resistant ...bacteria and fungi has highlighted the need for novel treatments. Coconut oil, with its known antimicrobial properties, presents an attractive candidate for combating these pathogens. This study aims to investigate the potential of coconut oil-loaded silica nanoemulsion (ON@SiO
2
) as a novel therapeutic agent against viral, antimicrobial-resistant bacteria, and fungal pathogens.
Results
The study synthesized coconut oil-loaded silica nanoemulsion (ON@SiO
2
) using an eco-friendly, cost-effective method with native coconut oil (CO). Characterization confirmed successful synthesis on the nanoscale with good distribution. Three nanoemulsion samples (ON-1@SiO
2
, ON-2@SiO
2
, and ON-3@SiO
2
) were prepared, with average particle sizes of 193 nm, 200 nm, and 325 nm, respectively. Evaluation of cytotoxicity on Vero-E6 cell lines indicated safety of ON-0@SiO
2
and ON-3@SiO
2
, with CC50 values of 97.5 mg/ml and 89.1 mg/ml, respectively. ON-3@SiO
2
demonstrated anti-Herpes I and II (HSV1 and HSV2) activity, with IC50 values of 1.9 mg/ml and 2.1 mg/ml, respectively. Additionally, ON-3@SiO
2
exhibited promising antibacterial activity against
E. coli, P. aeruginosa, S. aureus,
and
B. subtilis
, with MIC values of 25 mg/ml, 12.5 mg/ml, 25 mg/ml, and 3.12 mg/ml, respectively.
Conclusions
ON-3@SiO
2
showed potential antifungal activity against
C. albicans
, a unicellular fungus, with an MIC of 12.5 mg/ml. Overall, ON@SiO
2
possesses antiviral, antibacterial, and antifungal properties.
is a hazardous opportunistic pathogen that is involved in many serious human diseases and is considered to be an important foodborne pathogen found in many food types. Multidrug resistance (MDR)
...strains have recently spread and increased, making bacteriophage therapy an effective alternative to multiple drug-resistant pathogens. As a consequence, this research was conducted to describe the genome and basic biological characteristics of a novel phage capable of lysing MDR
isolated from food samples in Egypt. The host range revealed that KPP-5 phage had potent lytic activity and was able to infect all selected MDR
strains from different sources. Electron microscopy images showed that KPP-5 lytic phage was a podovirus morphology. The one-step growth curve exhibited that KPP-5 phage had a relatively short latent period of 25 min, and the burst size was about 236 PFU/infected cells. In addition, KPP-5 phage showed high stability at different temperatures and pH levels. KPP-5 phage has a linear dsDNA genome with a length of 38,245 bp with a GC content of 50.8% and 40 predicted open reading frames (ORFs). Comparative genomics and phylogenetic analyses showed that KPP-5 is most closely associated with the
genus in the
family. No tRNA genes have been identified in the KPP-5 phage genome. In addition, phage-borne virulence genes or drug resistance genes were not present, suggesting that KPP-5 could be used safely as a phage biocontrol agent.
Synthetic antimicrobials have a negative impact on food quality and consumer health, which is why natural antimicrobials are urgently needed. Coagulase-negative staphylococci (CoNS) has gained ...considerable importance for food poisoning and infection in humans and animals, particularly in biofilms. As a result, this study was conducted to control the CoNS isolated from food samples in Egypt. CoNS isolates were selected on the basis of their antibiotic susceptibility profiles and their biofilm-associated behavior. In this context, a total of 29 different bacteriophages were isolated and, in particular, lytic phages (6 isolates) were selected. The host range and physiological parameters of the lytic phages have been studied. Electron microscopy images showed that lytic phages were members of the families
(CoNShP-1, CoNShP-3, and CoNSeP-2 isolates) and
(CoNShP-2, CoNSsP-1, and CoNSeP-1 isolates). CoNShP-1, CoNShP-2, and CoNShP-3 were found to be virulent to
, CoNSsP-1 to
and CoNSeP-1 and CoNSeP-2 to
. Interestingly, the CoNShP-exhibited a typical polyvalent behavior, where not only lysis CoNS, but also other genera include
, methicillin-resistant
(MRSA), vancomycin-resistant
(VRSA),
and
. In addition, CoNShP-3 phage showed high stability at different temperatures and pH levels. Indeed, CoNShP-3 phage showed an antibiofilm effect against
CFS79 and
CFS43, respectively, while
CFS28 biofilm was completely removed. Finally, CoNShP-3 phage demonstrated a high preservative efficacy over short and long periods of storage against inoculated CoNS in chicken breast sections. In conclusion, this study highlights the control of CoNS pathogens using a polyvalent lytic phage as a natural antibacterial and antibiofilm agent from a food safety perspective.
New and natural antimicrobials as an alternative control system are now an urgent need to overcome stubborn bacterial infections. Salmonella Typhimurium has become the most frequent serovar ...responsible for salmonellosis in humans around the world. The high antimicrobial resistance and biofilm production make this pathogen more dangerous. We aimed to isolate a broad lytic phage to prevent Salmonella infection and reduce its biofilms. Using Salmonella Typhimurium (ST-4) as a host, seven phages were isolated, and only three phages showed clear lytic plaques, two members of the Siphoviridae family (vB_STS-1 and vB_STS-3) and one of the Myoviridae family (vB_STM-2). The vB_STM-2 phage was the most potent broad lytic phage, infecting 100% of tested Salmonella Typhimurium serovars and non-Salmonella strains. Additionally, the vB_STM-2 phage was thermostable at −20 to 55 °C up to 24 h, while at 65 and 75 °C, a significant (p < 0.05) titer reduction was observed after 7 days. Moreover, the phage seemed to be stable at different pHs (4–11) after one to twelve hours (hrs), while increasing the time made the phage more sensitive to the alkaline medium rather than the acidic medium. Interestingly, the vB_STM-2 phage had the capacity to diminish or eradicate the biofilms of tested Salmonella Typhimurium, e.g., ST-4, ST-19, ST-30, ST-37, ST-45 and ST-49 by 81.2%, 76.4%, 43.6%, 41%, 39.8% and 93.4%, respectively, at a titer concentration of 106 PFU/mL. Eventually, the vB_STM-2 phage showed significant (p < 0.05) efficacy in the elimination of Salmonella Typhimurium (ST-4) from contaminated chicken breasts at both storage periods with high titer stability. The Salmonella count showed a severe decline from 7.00 ± 0.63 log10 CFU/cm2 to 0.88 ± 0.17 log10 CFU/cm2 on the seventh day of the short-term storage, and from 5.13 ± 0.44 log10 CFU/cm2 to 1.10 ± 0.12 log10 CFU/cm2 on day 27 of the long-term assay. In both periods, the phage titers remained stable, with insignificant (p < 0.05) loss. Therefore, this phage is considered a prime candidate to combat multi-drug-resistant Salmonella Typhimurium and its biofilms.
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