Shaban R. M. Sayed

Antifungal silver nanoparticles: synthesis, characterization and biological evaluation

ABSTRACT Silver nanoparticles have a high antimicrobial activity and are broadly utilized for several disinfection purposes including water and materials’ sanitization for medical purposes. There have been comparatively few studies on using silver against plant pathogenic fungi. In this study, silver nanoparticles (Ag NPs) were used at concentrations of 0.0, 0.0002, 0.0005, 0.0007, 0.0009, 0.0014 and 0.0019 mol/L. Six different Rhizoctonia solani anastomosis groups (AGs) infecting cotton plants were treated in vitro with Ag NPs on Czapek Dox agar (CDA) and potato dextrose agar plates. The results showed that various concentrations of Ag NPs have antifungal properties to control R. solani AGs. The obtained results also revealed that strong inhibition of R. solani AGs was noticed on CDA at all concentrations.

Antimicrobial activity and green synthesis of silver nanoparticles using Trichoderma viride

ABSTRACT Green synthesis of nanoparticles has an increasing benefit because of the rising need for developing environmentally friendly, cost-effective and safe strategies for nanomaterials synthesis. In this study, we investigated the fungus Trichoderma viride, which is used for the synthesis of biogenic silver nanoparticles. The bioreduction of silver nanoparticles (Ag NPs) was observed spectrophotometrically, and the studied Ag NPs were characterized by ultraviolet–visible spectroscopy (UV–Vis), transmission electron microscopy and scanning electron microscopy. The Ag NPs synthesized by T. viride were observed as stabilized and polydispersed globular particles, in sizes ranging from 1 to 50 nm. The antibacterial potential of Ag NPs was evaluated against human pathogenic bacteria. The biogenic Ag NPs significantly inhibited the growth of all tested pathogenic bacteria.

Non liquid nitrogen-based-method for isolation of DNA from filamentous fungi

A simple, efficient, reliable and cost-effective method for isolation of total genomic DNA from fungi, suitable for polymerase chain reaction (PCR) amplification and other molecular applications was described. The main advantages of the method are: (1) does not require the use of liquid nitrogen for preparation of fungi DNA; (2) the mycelium is directly recovered from Petri-dish cultures; (3) the quality and quantity of DNA obtained are suitable for molecular assays; (4) the technique is rapid and relatively easy to perform; (5) it can be applied to filamentous fungi from soil as well as from a fungi from other environmental sources; and (6) it does not require the use of expensive and specialized equipment or hazardous reagents. This method does not require liquid nitrogen for fixation, grinding or storage at - 80°C, making it advantageous over other common protocols. Key words: Genomic DNA extraction, filamentous fungi, polymerase chain reaction (PCR) amplification.

Rapid Biological Synthesis of Silver Nanoparticles Using Plant Seed Extracts and Their Cytotoxicity on Colorectal Cancer Cell Lines

In this research we focused on the green synthesis of silver nanoparticles (AgNPs) using Pimpinella anisum seed extract. Furthermore, we evaluated their cytotoxicity on colorectal cancer (CRC) cell lines. Our results revealed the anti-cancerous cytotoxic potential of green synthesized AgNPs. Green synthesized AgNPs exhibited high cytotoxicity on colorectal adenocarcinoma CRC cells. They selectively killed cancer cells through suppression of proliferation, cell cycle arrest at the G2/M phase, and induction of apoptosis. Interestingly, between the two different clones, SW620 cells were more sensitive than HCT8 cells. Overall, our findings suggest that AgNPs could be effective cancer chemotherapeutic agents or a combination nano-drug in future anti-cancer therapy.

Evaluation of biological activities of chemically synthesized silver nanoparticles

Silver nanoparticles were synthesized by the earlier reported methods. The synthesized nanoparticles were characterized using ultraviolet-visible spectrophotometry (UV/Vis), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), and X-ray powder diffraction (XRD). The synthesized materials were also evaluated for their antibacterial activity against Gram positive and Gram negative bacterial strains. TEM micrograph showed the spherical morphology of AgNPs with size range of 40-60 nm. The synthesized nanoparticles showed a strong antimicrobial activity and their effect depends upon bacterial strain as AgNPs exhibited greater inhibition zone for Pseudomonas aeruginosa (19.1mm) followed by Staphylococcus aureus (14.8 mm) and S. pyogenes (13.6mm) while the least activity was observed for Salmonella typhi (12.5 mm) at concentration of 5 µg/disc. The minimum inhibitory concentration (MIC) of AgNPs against S. aureus was 2.5 µg/disc and less than 2.5 µg/disc for P. aeruginosa. These results suggested that AgNPs can be used as an effective antiseptic agent for infectious control in medical field.

An ultrastructural study of oogenesis and cell dynamics during cocoon shell secretion in the subterranean freshwater planarian Dendrocoelum constrictum (Platyhelminthes, Tricladida)

The ultrastructure of the ovary and the female atrium during cocoon formation was investigated in the subterranean freshwater planarian Dendrocoelum constrictum. In the peripheral portion of the ovary, the oogonia are recognized as undifferentiated germ cells, which are morphologically similar to neoblasts that have a high nucleus/cytoplasm ratio. Oocyte maturation is characterized by a marked growth of the cytoplasm because of the accumulation of cytoplasmic organelles and inclusions. The Golgi complexes begin to increase within the ooplasm and produce vesicles with an electron-dense content that fuse to produce larger spherical globules with homogeneous and electron-dense material. In the mature oocyte, the spherical globules migrate toward the cortical ooplasm, forming a continuous monolayer. We confirm that these spherical globules, which represent cortical granules rather than eggshell globules, vary in size up to 2μm and their electron-dense content shows concentric thin bands. After leaving the ovary through the oviduct, the mature and fertilized oocytes reach the female atrium where they are packaged with thousands of vitelline cells in the cocoon shell. Based on our ultrastructural analysis, we demonstrate that the wall of the cocoon shell is composed of two layers, each of which has a different origin. The shell granules extruded from the vitelline cells are involved in the secretion of the inner layer of the cocoon shell, whereas the outer layer of the cocoon shell is synthesized by the epithelial cells in the genital atrium.

Integrated control of white rot disease on beans caused by Sclerotinia sclerotiorum using Contans® and reduced fungicides application

This study was conducted to determine the compatibility of Contans® (Coniothyrium minitans) with fungicides against Sclerotinia sclerotiorum. Results showed that both Contans® and Topsin® significantly reduced the disease incidence caused by S. sclerotiorum by 90% and 95% survival plants, respectively when they were individually applied and compared to control. While, soil application of Contans® and Sumisclex mixture was the most effective in suppressing the white rot disease incidence that produced 100% survival plants, application of C. minitans combined with the reduced doses of fungicides would be advantageous in saving labor cost, thus increasing production efficiency of bean.

Bioengineered silver nanoparticles using Curvularia pallescens and its fungicidal activity against Cladosporium fulvum

Microorganisms based biosynthesis of nanomaterials has triggered significant attention, due to their great potential as vast source of the production of biocompatible nanoparticles (NPs). Such biosynthesized functional nanomaterials can be used for various biomedical applications. The present study investigates the green synthesis of silver nanoparticles (Ag NPs) using the fungus Curvularia pallescens (C. pallescens) which is isolated from cereals. The C. pallescens cell filtrate was used for the reduction of AgNO3 to Ag NPs. To the best of our knowledge C. pallescens is utilized first time for the preparation of Ag NPs. Several alkaloids and proteins present in the phytopathogenic fungus C. pallescens were mainly responsible for the formation of highly crystalline Ag NPs. The as-synthesized Ag NPs were characterized by using UV–Visible spectroscopy, X-ray diffraction and transmission electron microscopy (TEM). The TEM micrographs have revealed that spherical shaped Ag NPs with polydisperse in size were obtained. These results have clearly suggested that the biomolecules secreted by C. pallescens are mainly responsible for the formation and stabilization of nanoparticles. Furthermore, the antifungal activity of the as-prepared Ag NPs was tested against Cladosporium fulvum, which is the major cause of a serious plant disease, known as tomato leaf mold. The synthesized Ag NPs displayed excellent fungicidal activity against the tested fungal pathogen. The extreme zone of reduction occurred at 50 μL, whereas, an increase in the reduction activity is observed with increasing the concentration of Ag NPs. These encouraging results can be further exploited by employing the as synthesized Ag NPs against various pathogenic fungi in order to ascertain their spectrum of fungicidal activity.

New microsporidia, Glugea sardinellensis n sp (Microsporea, Glugeida) found in Sardinella aurita Valenciennes, 1847, collected off Tunisian coasts

A new microsporidia Glugea sardinellensis n. sp. found in the teleost fish Sardinella aurita Valenciennes collected from the Tunisian coasts. The parasite develops in a large xenomas measuring 1–16 mm in diameter and is generally visible with naked eye in the connective tissue around the pyloric caeca of the host. Xenoma were often rounded, but would be occasionally ovoid or irregular shape, generally creamy but rarely opaque, and filled with mature spores. The spores were unikaryotic pyriform measuring 5–5.5 (5.25±0.24) µm in length and 2.5–3 (2.75±0.24) µm in width. The posterior vacuole was large and occupied more than half of the spore. Ultrastructural study indicated that the mature spore has 13–14 coils of polar filament arranged in one layer, and a rough exospore. Intermediate stages were rare and randomly distributed in the xenoma. Merogonial and sporogonial stages were uni or binucleate. The plasma membrane surrounding the meront was irregular and indented. The mean prevalence was 18.3% and it varied according to season and locality. The distribution of prevalence according to fish size indicated that small fish were primarily affected. Phylogenetic analysis using the partial sequence of the SSU rDNA showed consistent association with species of the genus Glugea. The most closely related species was Glugea atherinae Berrebi, 1979 with 98.5% similarity.

Potential histopathological and molecular changes in rat vas deferens inhaled by Boswellia papyrifera and Boswellia carterii

Boswellia papyrifera and Boswellia carterii released from smoke contaminate indoor environment and consequently adversely affect humans as evidenced by respiratory disturbances. The aim of this study was to determine the effects of these plants on pathological and biochemical changes in vas deferens of albino rats. Animals were administered 4 g/kg body weight B. papyrifera and B. carterii daily for 120 days along with controls. Significant changes were observed in epithelial cell types and some cells showed signs of degeneration. The ultrastructural studies revealed marked changes in cytoplasmic organelles. Microvilli were missing and lysosomes were found in the cytoplasm. In addition, all treated groups plasma fructose and other biochemical parameters were decreased indicating reduced energy necessary for motility and contractility of spermatozoa. Many spermatozoa were disorganized and agglomerated. Data suggest that smoke from these plants adversely affects vas deferens.