Mona Kilany

Facile microwave-assisted synthesis of Te-doped hydroxyapatite nanorods and nanosheets and their characterizations for bone cement applications

In this work, the authors have fabricated the nanorods and nanosheets of pure and Te-doped HAp with different Te concentrations (0.04, 0.08, 0.16, 0.24wt%) by microwave-assisted technique at low temperature. The crystallite size, degree of crystallinity and lattice parameters are calculated. FE-SEM study confirms that the fabricated nanostructures are nanorods of diameter about 10nm in undoped and at low concentration of Te doping. However, at and higher concentration, it becomes nanosheets of about 5nm thickness. X-ray diffraction, FT-IR and FT-Raman studies shows that the prepared products are of HAp and Te has been successfully incorporated. From EDX the Ca/P molar ratio of the pure HAp is about 1.740, while this ratio for 0.04, 0.08, 0.16, 0.24 wt% Te doped is about 1.53, 1.678, 1.724, 1.792, respectively. Crystallite size was found to be increased with Te doping from 15nm to 62nm. The value of dielectric constant is found to be enhanced at higher concentrations of Te. The values of linear absorption coefficient were also determined and show that the prepared material with Te doping is more absorbable than pure and will be highly applicable in radiation detection applications. Furthermore, the antimicrobial potential of pure and Te doped HAp was examined against some Gram- negative and positive bacteria and fungi by agar disk diffusion method. The results demonstrated that the antimicrobial activity of Te doped HAp is stronger than that of pure HAp where it exhibited the highest activity against Bacillus subtilis>Candida albicans>Shigella dysenteriae.

Biocontrol of apple blue mould by new yeast strains: Cryptococcus albidus KKUY0017 and Wickerhamomyces anomalus KKUY0051 and their mode of action

Seeking new yeast strains having the ability to protect apple fruits against blue mould for a long time under different storage conditions was the main goal of this work. Based on the in vitro test, yeast strains KKUY0017 and KKUY0051 were selected as the most effective antagonists against Penicillium expansum. Sequencing of 26S rDNA of both yeasts confirmed that the identity of KKUY0017 and KKUY0051 was Cryptococcus albidus and Wickerhamomyces anomalus, respectively. The two strains protected the apple fruits from the blue mould disease under a wide range of temperature (5–30°C); however, W. anomalus KKUY0051 was more effective. At 25°C, W. anomalus KKUY0051 involved in the reduction of disease severity and disease incidence of blue mould by 56.49% and 57.78%, respectively. When either of the two yeasts was applied in concentration of 108 or 109 cells/mL, the maximum reduction in disease severity and disease incidence was achieved. Under cold storage (5°C), both yeast strains succeeded to protect the apple fruits free from the infection up to 24 days. Electron micrograph showed a fit attachment between the cells of C. albidus KKUY0017 and the fungal hyphae leading to the degrading of the hyphae; however, W. anomalus killed the fungal hyphae without direct attachment to them. Gas chromatography–mass spectrometry analysis of the cell-free extract of W. anomalus KKUY0051 revealed the presence of toxic compounds such as the nitrophenol derivatives. The results support the assumption that the main mode of action of this yeast is by killer toxins. We conclude that application of these yeasts under cold storage condition could keep the apple fruits free from blue mould infection for a long time.

Role of Soil Amendment with Micronutrients in Suppression of Certain Soilborne Plant Fungal Diseases: A Review

Micronutrients might affect the resistance of plants to pathogens or disease tolerance. In addition, there are conflicting reports about the effect of micronutrients on plant diseases, and many features that impact this response are unclear. Soil is crucial for micronutrient storage such as Br, Mn, Zn, Cu, Fe and Cl, which can reduce the severity of plant disease by increasing disease tolerance and resistance of plants to pathogens. In particular, micronutrients have significant effects on controlling soilborne plant fungal diseases. Micronutrients can reduce disease to a satisfactory level or at least to a level at which further control by other conventional organic biocides or traditional practices is cheap and more fruitful. This review article recaps the latest information concerning the effect of micronutrients, such as Br, Mn, Zn, Cu, Fe, Cl and Mo, on disease resistance and tolerance and their use in sustainable agriculture. Here, our main focus is the critical analysis of various factors responsible for the suppression of certain plant fungal diseases due to micronutrients. In addition, we have identified efforts to determine key areas where sincere research efforts are still needed to develop strategies for manipulating micronutrient application in such a way that it could be more efficiently utilised in managing soilborne plant fungal diseases.

Microbial Suppressiveness of Pythium Damping-Off Diseases

Damping-off diseases incited by different species of Pythium are a persistent problem worldwide, often resulting in reduced yields and occasionally resulting in major crop damage. There have been increasing restrictions on the use of chemical fungicides, and the development of disease-suppressive biocontrol agents has become a major goal of horticultural industry. Consequently, investigation of the population dynamics and tripartite interaction between the plant, pathogen and antagonist is crucial to understand the mechanistic pathway of biocontrol agents (BCA).

Development of Rift Valley fever (RVF) vaccine by genetic joining of the RVF-glycoprotein Gn with the strong adjuvant subunit B of cholera toxin (CTB) and expression in bacterial system

One of the mosquito-borne zoonotic diseases is the Rift Valley fever virus (RVFV). Currently, there is no completely licensed vaccine that can be used to vaccinate animals or humans outside endemic areas. The aim of this work was to use the RVFV glycoprotein (Gn) and the subunit B of cholera toxin (CTB) at gene level and build up fused recombinant vaccine. The gene of CTB was joined to the gene Gn to work as an adjuvant in the resulting fusion protein. The designed merged genes (CTB-Gn) was tested for restriction sites, open reading frames, expected fusion protein tertiary structure and antigenicity using computer software. The insert sequence was submitted to the BioProject (GenBank). The insert was subcloned into the pQE-31 expression plasmid. The target recombinant protein (rCTB-Gn) was expressed in M15 bacteria, purified and identified by protein gel electrophoresis. The insert got the accession No: PRJNA386723. Analysis of the designed rCTB-Gn protein revealed that it had the right 3D structure, immunogenic and at the correct molecular weight. The presence of the CTB in the proposed vaccine will augment its immunogenicity. Doses and protection levels of the vaccine need to be manipulated.

TH1/TH2 chemokines/cytokines profile in rats treated with tetanus toxoid and Euphorbia tirucalli

Natural products, including their purified materials, play a remarkable role in drug development. The Euphorbiaceae family, mainly Euphorbia tirucalli, is used in some traditional medicine, and has evidence that its latex comprises immunomodulatory properties and cytokine production. This study aimed to measure the in vivo production of chemokines (IL-1α, IL-1β, IL-12, and RANTES), TH1 cytokines (IFN-γ, TNF-α, GM-CSF, and IL-2) and TH2 cytokines (IL-4, IL-6, IL-10, and IL-13) in rats after treatments with ethanol latex extract of E. tirucalli. Vaccine treated and untreated rats were divided into seven groups to assess antimicrobial activities of the extracted components. After completion of the treatment schedule, blood was withdrawn and sera were collected. The results showed that the main component of the extract was a euphol compound. The extract showed antimicrobial activity and had the ability to modulate innate and adaptive immunity. Animals treated with extract for only 7 days before vaccination showed higher levels of antibody production. The extract showed antibacterial and antifungal activities. The extract could stimulate both adaptive and innate immunity. Pre-treatment with the extract increased immune responses in vaccinated animals, indicating the usefulness of the extract before immunization.

Cellular proliferation/cytotoxicity and antimicrobial potentials of green synthesized silver nanoparticles (AgNPs) using Juniperus procera

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Inhibition of human pathogenic bacteria by Moringa oleifera cultivated in Jazan (Kingdom of Saudi Arabia) and study of synergy to amoxicillin

Background The spread of multidrug-resistant strains of bacteria to most antibiotics has led to intensive searches for effective strategies to overcome bacterial infections. Aim Moringa oleifera could be a potentially useful agent for many therapeutic applications, especially antimicrobial. Settings and design The leaves of M. oleifera were collected in October 2014 from Jazan, located in the southern region of the Kingdom of Saudi Arabia. Materials and methods Different organic solvents were used to extract antimicrobial substances in the plant leaves. The antibacterial activity of each leaf extract was determined in vitro and compared with some antibiotics. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of both plant extracts and amoxicillin were investigated against Bacillus spp. An evaluation of the synergistic effects of amoxicillin and plant extract was carried out. Results The results showed that an ethanol extract is the best organic solvent for extracting the antimicrobial substance from M. oleifera. In addition, the antibacterial potential of an ethanol extract is comparable to that of some commercial antibiotics. MIC and MBC of the plant extract were 320 and 620 μg/ml, respectively, whereas MIC and MBC of amoxicillin were 25 and 50 μg/ml, respectively. The fractional inhibitory concentration of the plant extract and amoxicillin was determined to be 0.125 and 0.25, respectively. Therefore, ethanolic plant extract can be considered a good synergistic factor to amoxicillin, yielding a fractional inhibitory concentration index 0.375 ≤ 0.5 of the combination. Conclusion M. oleifera leaves may serve as a natural alternative to antibiotics. Moreover, M. oleifera can boost the inhibitory effect of amoxicillin, leading to a reduction of administration dose as well as minimizing the side effects of antibiotics.

Assessment the microbiological and molecular aspects of soil isolated bacteria that suppress Pythium ultimum in Abha/KSA

Background Pythium ultimum is largely threatening many economically important plants by causing seedling damping-off disease. Microbial control approach is considered a new, effective, and safe trend in the eradication of phytopathogens. Aims The current work focused on the isolation and molecular identification of soil isolated bacteria that suppress the damping-off-causing pathogen (P. ultimum). Moreover, optimization of environmental factors and detection of the mode of action of P. ultimum suppression was taken into consideration. Materials and methods Soil bacteria were isolated and screened for their antagonistic potential toward P. ultimum. The most vigorous isolate was characterized and identified. Some environmental factors were optimized using a well-plate assay. The inhibitory effect of bacteria, whether fungistatic or fungicidal, was detected. Mode of action of fungal inhibition was studied as well. Statistical analysis Statistical analysis was carried out using one-way analysis of variance in Excel. Results The bacterial isolate was identified as Enterococcus faecalis. The extracellular filtrate presented higher fungal inhibition (68%) compared with the bacterial cells (53%). The environmental factors for fungal inhibition were optimized to be pH 8, 28°C, 100% inoculum size, and third day of incubation reaching maximal values of 75, 76, 81, and 83%, respectively. Conclusion E. faecalis is a promising fungicidal agent against P ultimum through the production of diffusible metabolites.