The immune enhancer, thymoquinone, and the hope of utilizing the immune system of Aedes caspius against disease agents

Insects have developed an efficient defence system against  microorganisms, which involves both humoral and cellular mechanisms. Recent studies on insect defence system are aimed at utilizing it inthe battle against mosquito-borne diseases. However, mounting immune responses of insects has proved to impose fitness costs. The current study was conducted to test the costs of enhancing the immune responses of Aedes caspius by oral administration of thymoquinone, the active ingredient of the black seed oil, Nigella sativa L. (Ranunculaceae). The obtained results showed an effective humoral activity against Micrococcus luteus (NCTC 2665, Sigma-Aldrich, UK) and Bacillus cereus when mosquitoes were injected with lipopolysaccharide (LPS), Bacillus thuringiensis or B. cereus. However, this activity showed no effect against B. thuringiensis. Furthermore, oral administration of thymoquinone enhanced the humoral activity against B. cereus but not against B. thuringiensis. On the other hand, thymoquinone-enhanced immunity imposed reproductive costs in terms of higher percentages of follicular apoptosis and resorption. This observation has been confirmed by the semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR) analysis, which showed a relatively higher expression of selected caspases genes, namely: CASP 18, CASP 19 and CASP 20, but not CASP 21, transcripts in immune enhanced mosquitoes compared to non-enhanced ones. Based on these results, this study suggests that enhancing the humoral activity by thymoquinone proved to be costly in terms of triggering follicular apoptosis and resorption. Thus, as part of the scenario ofimmunity-reproduction conflict, it was concluded that the impact of immune stimulation and/or enhancement on the vector reproduction constitutes a limiting factor to the utilization of thymoquinone in the immuno-control strategy against mosquito-borne diseases

Molecular diagnostics and phylogenetic analysis of ‘Candidatus phytoplasma asteris’ (16SrI- Aster yellow group) infecting banana (Musa spp.)

The presence of phytoplasma in diseased banana plants exhibiting acute stunting symptoms was detected by the polymerase chain reaction using a primer set specific for the 16SrRNA gene of phytoplasma. The amplified DNA fragments of 1500 bp were cloned in pGEMT-Easy plasmid cloningvector and sequenced. The BLASTN and phylogenetic analyses revealed the infecting agents to be the closely related members of the ‘Candidatus phytoplasma asteris’ (16Sr I-Aster yellow) group

Potential therapeutic applications of microbial surface-activecompounds

Numerous investigations of microbial surface-active compounds or biosurfactants over the past two decades have led to the discovery of many interesting physicochemical and biological properties including antimicrobial, anti-biofilm and therapeutic among many other pharmaceutical and medical applications. Microbial control and inhibition strategies involving the use of antibiotics are becoming continually challenged due to the emergence of resistant strains mostly embedded within biofilm formations that are difficult to eradicate. Different aspects of antimicrobial and anti-biofilm control are becoming issues of increasing importance in clinical, hygiene, therapeutic and other applications. Biosurfactants research has resulted in increasing interest into their ability to inhibit microbial activity and disperse microbial biofilms in addition to being mostly nontoxic and stable at extremes conditions. Some biosurfactants are now in use in clinical, food and environmental fields, whilst others remain under investigation and development. The dispersal properties of biosurfactants have been shown to rival that of conventional inhibitory agents against bacterial, fungal and yeast biofilms as well as viral membrane structures. This presents them as potential candidates for future uses in new generations of antimicrobial agents or as adjuvants to other antibiotics and use as preservatives for microbial suppression and eradication strategies

Mosquito vectors survey in the AL-Ahsaa district of eastern Saudi Arabia

The present study aimed to identify the mosquito vectors distributed throughout AL-Ahsaa district situated in the eastern region of Saudi Arabia. Mosquito larvae were collected seasonally for one year (October 2009 to September 2010) from different breeding sites in seven rural areas utilizing long aquatic nets. Salinity and pH of these breeding sites were also measured seasonally. The survey revealed the presence of five mosquito species, Aedes caspius Pallas (Diptera: Culicidae), Anopheles multicolor Cambouliu, Culex perexiguus Theobald, Culex pipiens L., and Culex pusillus Macquart, representing three genera; four of them (Ae. caspius, An. multicolor, Cx. perexiguus, and Cx. pipiens) are important vectors of diseases. Ae. caspius is the most common vector followed by Cx. pipiens and then Cx. perexiguus. Mosquitoes in AL-Ahsaa are prevalent in both winter and spring seasons, rarely encountered in summer, and are found in moderation during the autumn months. These results are compared with results of other regions in the Kingdom of Saudi Arabia

Histologic and apoptotic changes induced by titanium dioxide nanoparticles in the livers of rats

Saud Alarifi,1 Daoud Ali,1 Amin A Al-Doaiss,1,2 Bahy A Ali,1,3 Mukhtar Ahmed,1 Abdulaziz A Al-Khedhairy11Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia; 2Anatomy and Histology Department, Faculty of Medicine, Sana'a University, Sana'a, Republic of Yemen; 3Genetic Engineering and Biotechnology Research Institute, City for Scientific Research and Technology Applications, Alexandria, EgyptAbstract: Titanium dioxide (TiO2) nanoparticles are among the top five nanoparticles used in consumer products, paints, and pharmaceutical preparations. Given that exposure to such nanoparticles is mainly via the skin and inhalation, the present study was conducted in male Wistar albino rats (Rattus norvegicus). Our aim was to investigate the effect of TiO2 nanoparticles on hepatic tissue in an attempt to understand their toxicity and the potential effect of their therapeutic and diagnostic use. To investigate the effects of TiO2 nanoparticles on liver tissue, 30 healthy male Wistar albino rats were exposed to TiO2 nanoparticles at doses of 63 mg, 126 mg, and 252 mg per animal for 24 and 48 hours. Serum glutamate oxaloacetate transaminase and alkaline phosphatase activity was altered. Changes in hepatocytes can be summarized as hydropic degeneration, cloudy swelling, fatty degeneration, portal and lobular infiltration by chronic inflammatory cells, and congested dilated central veins. The histologic alterations observed might be an indication of hepatocyte injury due to the toxicity of TiO2 nanoparticles, resulting in an inability to deal with accumulated residues from the metabolic and structural disturbances caused by these nanoparticles. The appearance of cytoplasmic degeneration and destruction of nuclei in hepatocytes suggests that TiO2 nanoparticles interact with proteins and enzymes in hepatic tissue, interfering with antioxidant defense mechanisms and leading to generation of reactive oxygen species which, in turn, may induce stress in hepatocytes, promoting atrophy, apoptosis, and necrosis. More immunohistochemical and ultrastructural investigations are needed in relation to TiO2 nanoparticles and their potential effects when used as therapeutic and diagnostic tools.Keywords: TiO2 nanoparticles, rats, liver, histology, TUNEL assay, alkaline phosphatase, apoptosi

Oxidative stress contributes to cobalt oxide nanoparticles-induced cytotoxicity and DNA damage in human hepatocarcinoma cells

Saud Alarifi,1 Daoud Ali,1 Al Omar Suliman Y,2 Maqusood Ahamed,3 Maqsood A Siddiqui,2 Abdulaziz A Al-Khedhairy21Cell and Molecular Laboratory, Department of Zoology, Faculty of Science, King Saud University, Riyadh, Saudi Arabia; 2Faculty of Science, Department of Zoology, King Saud University, Riyadh, Saudi Arabia; 3King Abdullah Institute for Nanotechnology, King Saud University, Riyadh, Saudi ArabiaBackground: Cobalt oxide nanoparticles (Co3O4NPs) are increasingly recognized for their utility in biological applications, magnetic resonance imaging, and drug delivery. However, little is known about the toxicity of Co3O4NPs in human cells.Methods: We investigated the possible mechanisms of genotoxicity induced by Co3O4NPs in human hepatocarcinoma (HepG2) cells. Cell viability, reactive oxygen species (ROS), glutathione, thiobarbituric acid reactive substance, apoptosis, and DNA damage were assessed in HepG2 cells after Co3O4NPs and Co2+ exposure.Results: Co3O4NPs elicited a significant (P < 0.01) reduction in glutathione with a concomitant increase in lipid hydroperoxide, ROS generation, superoxide dismutase, and catalase activity after 24- and 48-hour exposure. Co3O4NPs had a mild cytotoxic effect in HepG2 cells; however, it induced ROS and oxidative stress, leading to DNA damage, a probable mechanism of genotoxicity. The comet assay showed a statistically significant (P < 0.01) dose- and time-related increase in DNA damage for Co3O4NPs, whereas Co2+ induced less change than Co3O4NPs but significantly more than control.Conclusion: Our results demonstrated that Co3O4NPs induced cytotoxicity and genotoxicity in HepG2 cells through ROS and oxidative stress.Keywords: cobalt oxide nanoparticles, HepG2 cells, cytotoxicity, oxidative stress, DNA damag

Gold quantum dots impair the tumorigenic potential of glioma stem-like cells via β-catenin downregulation in vitro

Rizwan Wahab,1,2,* Neha Kaushik,3,* Farheen Khan,4 Nagendra Kumar Kaushik,5 Su-Jae Lee,3 Eun Ha Choi,5 Abdulaziz A Al-Khedhairy1 1Zoology Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia; 2Al-Jeraisy, Chair for DNA Research, King Saud University, Riyadh 11451, Saudi Arabia; 3Department of Life Science, Hanyang University, Seoul 04763, South Korea; 4Chemistry Department, Faculty of Science, Taibah University, Yanbu 42353, Saudi Arabia; 5Plasma Bioscience Research Center/Applied Plasma Medicine Center, Department of Electrical and Biological Physics, Kwangwoon University, Seoul 01897, South Korea *These authors contributed equally to this work Background: Over the past several decades, the incidence of solid cancers has rapidly increased worldwide. Successful removal of tumor-initiating cells within tumors is essential in the field of cancer therapeutics to improve patient disease-free survival rates. The biocompatible multivarient-sized gold nanoparticles (MVS-GNPs) from quantum dots (QDs, Methods: Herein, MVS-GNPs synthesized and characterized by means of X-ray diffraction pattern (XRD) and transmission electron microscopy (TEM) techniques. Afterwards, interaction of these GNPs with glioma stem-cell like cells along with cancer cells were evaluated by MTT, cell motility, self-renewal assays and biostatistics was also applied.Results: Among these GNPs, G-QDs contributed to reduce metastatic events and spheroid cell growth, potentially blocking the self-renewal ability of these cells. This study also uncovers the previously unknown role of the inhibition of CTNNB1 signaling as a novel candidate to decrease the tumorigenesis of glioma spheroids and subsequent spheroid growth. The accurate and precise biostatistics results were obtained at quantify level.Conclusion: In summary, G-QDs may exhibit possible contribution on suppressing the growth of tumor-initiating cells. These data reveal a unique therapeutic approach for the elimination of residual resistant stem-like cells during cancer treatment. Keywords: multivarient gold nanoparticles, epithelial-mesenchymal transition, solid tumor, brain cancer, self-renewal, cellular movement, biostatistic

Antibacterial properties of silver nanoparticles synthesized using Pulicaria glutinosa plant extract as a green bioreductant

Mujeeb Khan,1 Shams Tabrez Khan,2 Merajuddin Khan,1 Syed Farooq Adil,1 Javed Musarrat,2 Abdulaziz A Al-Khedhairy,2 Abdulrahman Al-Warthan,1 Mohammed Rafiq H Siddiqui,1 Hamad Z Alkhathlan1 1Department of Chemistry, 2Zoology Department, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia Abstract: The antibacterial properties of nanoparticles (NPs) can be significantly enhanced by increasing the wettability or solubility of NPs in aqueous medium. In this study, we investigated the effects of the stabilizing agent on the solubility of silver NPs and its subsequent effect on their antimicrobial activities. Silver NPs were prepared using an aqueous solution of Pulicaria glutinosa plant extract as bioreductant. The solution also acts as a capping ligand. During this study, the antimicrobial activities of silver NPs, as well as the plant extract alone, were tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Micrococcus luteus. Silver NPs were prepared with various concentrations of the plant extract to study its effect on antimicrobial activity. Interestingly, various concentrations of P. glutinosa extract did not show any effect on the growth of tested bacteria; however, a significant effect on the antimicrobial property of plant extract capped silver NPs (Ag-NPs-PE) was observed. For instance, the half maximal inhibitory concentration values were found to decrease (from 4% to 21%) with the increasing concentrations of plant extract used for the synthesis of Ag-NPs-PE. These results clearly indicate that the addition of P. glutinosa extracts enhances the solubility of Ag-NPs-PE and, hence, increases their toxicity against the tested microorganisms. Keywords: antibacterial activity, silver nanoparticles, plant extract, Pulicaria glutinos