Effects of Quorum Quenchers on Aspergillus fumigatus Conidia Aggregation, Adhesion to Surfaces, and Biofilm Formation

Aspergillus fumigatus can produce in vitro an extracellular hydrophobic matrix with biofilm features under static growth conditions. Microbial quorum sensing (QS) system regulates genetic competence and biofilm formation. Notwithstanding, triclosan, as a synthetic antimicrobial, disrupts QS signal in some bacteria, yeasts, and dermatophytes through blocking the biosynthesis of amino acid and fatty acids in the microbes. In this study, triclosan quorum quenching role as well as the effects of microbial quorum quenchers, furanone, farnesol and tyrosol were investigated against A. fumigatus for the first time. Amphotericin B (AMB), a common antifungal agent used against A. fumigatus infection, carries adverse effects against human health. So, triclosan’s antifungal effect in combination with AMB was also studied. Microbial cells’ detrimental attachment and biofilm formation on the indwelling medical implants, healthcare and hospital facilities, prompts interests to introduce feasible and cost-effective methods for eliminating/reducing microbial attachment to the surfaces. Using water contact angle (WCA) measurements, hydrophobicity of some hydrophilic surfaces (glass, acrylic, HDPE, nylon 6 and UPVC), and hydrophobic surfaces (PTFE and silicone) was measured following coating them with the mentioned antimicrobial agents. A. fumigatus conidia were exposed to the agents and the subsequent changes in the conidial viability, biofilm biomass production, total and EPS-related protein/ polysaccharide/ and nucleic acid were studied. The effect of AMB was weaker than the other agents on mitigating the biofilm formation. eDNA release was observed from A. fumigatus mycelia treated with triclosan, tyrosol and farnesol as compared with untreated control group. This eDNA release appeared to be due to necrosis occurrence in the treated samples verified by gel electrophoresis and protein quantity analysis. As a novel finding, the necrosis induced by triclosan followed by apoptosis induced by AMB resulted in a synergistic interaction to reduce the conidia viability even at the sub-MIC doses of triclosan and AMB. Confocal microscopy of the A. fumigatus exposed to triclosan-AMB combination confirmed the synergistic interaction between them against the fungus biofilm. Assaying for hydrophobicity of the conidia cell wall revealed a change from hydrophobic to hydrophilic property. ags3 down-regulation approved with real-time PCR assay showed triclosan’s quorum sensing inhibitory role against A. fumigatus. This was through inhibiting conidia aggregation, and hence prohibiting initiation of quorum sensing signalling pathway. Through SDS-PAGE assay it was established that the conidia cell wall hydrophobic rodlet layer was absent in farnesol-treated sample. This study revealed some of the physio-chemical properties that are involved in A. fumigatus conidia attachment to the surfaces. This work for the first time established that hydrophobic surfaces, PTFE and silicone, coated with farnesol showed hydrophilicity, while AMB changed UPVC surface charge from hydrophilic to hydrophobic. Taken together, besides influencing the conidia cell wall hydrophobicity, farnesol and AMB can also be used to coat the surfaces in clinical healthcare settings to diminish hydrophobic/hydrophilic microbial cells attachment to the surfaces

Antifungal effect of triclosan on Aspergillus fumigatus: quorum quenching role as a single agent and synergy with liposomal amphotericin-B

The purpose of this research was to determine Aspergillus fumigatus conidial viability and its biofilm formation upon treatment with triclosan and amphotericin-B loaded liposomes. A. fumigatus was treated with the antimicrobials, triclosan and liposomal amphotericin-B (L-AMB), in single and combined supplementation. To quantify the cells’ viability upon treatments, resazurin-based viability assay was performed. Confocal laser scanning microscopy was done by applying FUN-1 stain to screen the role of the agents on extracellular polymeric substances. Total A. fumigatus biomass upon treatments was estimated by using crystal violet-based assay. To study the agents’ effect on the conidial viability, flow cytometry analysis was performed. Expression levels of A. fumigatus genes encoding cell wall proteins, α-(1,3)-glucans and galactosaminogalactan were analysed by real-time polymerase chain reaction assay. A synergistic interaction occurred between triclosan and L-AMB when they were added sequentially (triclosan + L-AMB) at their sub-minimum inhibitory concentrations, the triclosan and L-AMB MICs were dropped to 0.6 and 0.2 mg/L, respectively, from 2 to 1 mg/L. Besides, L-AMB and triclosan contributed to the down-regulation of α-(1,3)-glucan and galactosaminogalactan in A. fumigatus conidia and resulted in less conidia aggregation and mycelia adhesion to the biotic/abiotic surfaces; A. fumigatus conidia-became hydrophilic upon treatment, as a result of rodlet layer being masked by a hydrophilic layer or modified by the ionic strength of the rodlet layer. In A. fumigatus, the potential mechanisms of action for L-AMB might be through killing the cells and for triclosan through interrupting the cells’ development as a consequence of quorum quenching

Quorum quenchers affect the virulence regulation of non-mucoid, mucoid and heavily mucoid biofilms co-cultured on cell lines.

Biofilm formation conferring pathogenicity is a survival strategy for Pseudomonas aeruginosa. P. aeruginosa's virulence may differ due to differences in host-microbe interactions and the growth environment. The epithelial cell line within the respiratory system and the keratinocytes on the skin form the first physical barrier of defence. P. aeruginosa spp. biofilm formation and virulence factor secretion with and without quorum quenching (QQ) treatment was studied in co-culture using A549 and HaCaT cell lines; pyocyanin and rhamnolipid productions and elastolytic activity as virulence factors were quantified by independent assays. Biofilm formation was evaluated under dynamic conditions by quantifying total carbohydrates, alginate, proteins and eDNA. A sandwich ELISA was performed to study IL-8 secretion by the epithelial cells. The difference in gene expression of the quorum sensing (QS) and virulence factors between strains during individual and combination treatments was analysed by qPCR. Combination treatment by farnesol and tyrosol was more effective against P. aeruginosa biofilms when grown in co-cultures. The strain RBHi was found to be 3 to 4 times more virulent compared to PAO1 and NCTC 10,662, respectively, and combination treatment was more effective against RBHi strain when grown in co-culture with A549 cell line. The addition of quorum quenchers (QQs) individually and in combination reduced IL-8 secretion by A549 cells. Relative mRNA expression showed upregulation of the QS genes and virulence factors. Co-culture of P. aeruginosa and HaCaT cell line showed a general decrease in gene expression, especially in the case of P. aeruginosa RBHi when treated with farnesol and tyrosol combination.Key points• Differentiating the interactions of biofilm formed by different phenotypes of P. aeruginosa, NCTC 10,662 (non-mucoid), PAO1 (semi mucoid) and RBHi (heavily mucoid).• Biofilm formed by these P. aeruginosa strains on two commonly afflicted tissues represented by A549 (lung) and HaCaT (skin) cell lines.• Anti-biofilm/anti-virulence roles of quorum quenchers, tyrosol and farnesol in co-cultures. [Abstract copyright: © 2021. The Author(s).

Development of Voice Onset Time in Arabic

The research investigated development of voice onset time (VOT) contrasts in children who spoke Jordanian Arabic. The factors investigated were: (1) the age at which VOT contrast is acquired; and (2) the role of place of articulation and emphasis on VOT development. One hundred and twenty children (60 males, 60 females; age range 2;0–7;11) produced word-initial plosives. Linear Mixed Model (LMM), Bonferroni post hoc and t test analyses were conducted on the data. Results revealed that age, place of articulation, and emphasis had significant effects on VOT. In addition, Arabic appeared to follow the general trend of VOT development reported for other voicing languages

The effect of Multiple Intelligences Theory-based Strategy on Achieving the Concepts of Jurisprudence among 8th Grade Students

This study investigated the effect of using a teaching strategy that is based on multiple intelligences theory (MIT) on achieving the concepts of Jurisprudence among 8th grade students. The study’s sample consisted of 104 students divided into four groups: two experimental groups taught by using a teaching strategy that was based on multiple intelligences theory (MIT); and two control groups examined in the traditional method. To achieve the objectives of the study, an achievement test was used. The results of the study showed a statistically significant difference at (a=0.05) on achieving jurisprudence concepts among 8th grade students that may be attributed to using a teaching strategy based on MIT. There was no effect for the interaction between teaching strategy and student's gender on achieving Jurisprudence concepts among 8th grade students

Muhammad Saw dan Peletakan Dasar Peradaban Islam

. Sejarah pra-Islam dan pasca datangnya nabi Muhammad di tengah peradaban bangsa Arab tentunya merupakan suatu kondisi yang sangat bipolar. Di satu sisi, peradaban pra-Islam banyak terjadi perilaku buruk seperti permusuhan, perselisihan, ketidakadilan, penindasan bahkan pembunuhan merupakan suatu tradisi dekonstruktif dalam tatanan bangsa Arab. Tentunya, hal ini sangat berbeda ketika Muhammad saw. (keturunan Arab) lahir, terjadi Perubahan tatanan yang sangat signifikan mulai dari konsteks keilmuan, sosial, ekonomi, dan aspek-aspek lainnya. Secara kompeherensif, aspek tersebut di atas direkonstruksi dari mukjizat nabi, yakni Alquran sebagai pedoman dasar dan berupa dari tata cara berperilaku nabi, ucapan dan way of life nabi yang terakumulasi dalam hadits mampu menggeser peradaban yang terbelakang menjadi perabadan yang sangat maju di berbagai lini. Penelitian ini mencoba untuk mengkonstelasikan dan mengkomparasikan peradaban bangsa Arab pra Nabi hingga Nabi dilahirkan dan membawa misi revolusioner dengan munculnya peradaban baru, peradaban Islam

Evaluation of FRP concrete compression member under repeated load and harsh environment

Strengthening and rehabilitation have been increasingly applied in many structures to improve their capacity and serviceability. Fiber Reinforced Polymer (FRP) materials are universally known for their ability to improve the load capacity of damaged structural elements because of their high linear-elastic behavior. However, enhancing the capacity of structural elements that are exposed to repeated load coupled with harsh environment is an area that requires further investigation. This research focused on experimental analysis of the behavior and response of confined and unconfined concrete compression members (300mm x 150mm) under repeated load while exposed to 1440 cycles of seawater splash zone in United Arab Emirates (UAE). Confining concrete compression members with Carbon Fiber Reinforced Polymer (CFRP) and Glass Fiber Reinforced Polymer (GFRP) sheets have increased the load capacity compared to the control sample at room temperature by 110% and 84%, respectively. Results showed that the average value of compressive strength for the confined concrete exposed to sea water splash zone conditions for CFRP and GFRP specimens has decreased by 33% and 23%, respectively, compared to the confined concrete in the room temperature. However, GFRP specimens showed higher performance in compressive strength under sea water splash zone than those of the CFRP specimens. Different mode of failures such as delamination, de-bonding and combination of such modes were observed and related to various exposure factors and mechanical properties

Knowledge Regarding Secondary Prevention Lifestyle Practices Among Patients with Ischaemic Heart Disease in Oman : Pilot study

Objectives: Secondary prevention of ischaemic heart disease (IHD) is very important. This study aimed to assess knowledge of necessary lifestyle changes among Omani patients diagnosed with IHD. Methods: This cross-sectional pilot study took place between October 2015 and February 2016 at the Sultan Qaboos University Hospital (SQUH), Muscat, Oman. A total of 30 random patients with IHD from the Cardiology Outpatient Clinic of SQUH were included. A 30-item survey was used to determine patients’ knowledge of necessary lifestyle practices following their IHD diagnosis, with scores of <70% indicating poor knowledge. Results: Overall, 21 patients (70.0%) had low knowledge levels. Scores ranged from 38.9−94.4% (mean: 60.7% ± 14.1%). No demographic factors were found to predict low scores, although there were some differences in individual questions. Conclusion: Low knowledge levels regarding lifestyle changes were observed among IHD patients in Oman. More efforts should be made to educate these patients for the secondary prevention of IHD