Tyrosol and farnesol are quorum-sensing molecules produced by Candida albicans which accelerate and block, respectively, the morphological transition from yeasts to hyphae. In this study, we have investigated the secretion of tyrosol by C. albicans and explored its likely role in biofilm development. Both planktonic (suspended) cells and biofilms of four C. albicans strains, including three mutants with defined defects in the Efg 1 and Cph 1 morphogenetic signaling pathways, synthesized extracellular tyrosol during growth at 37°C. There was a correlation between tyrosol production and biomass for both cell types. However, biofilm cells secreted at least 50% more tyrosol than did planktonic cells when tyrosol production was related to cell dry weight. The addition of exogenous farnesol to a wild-type strain inhibited biofilm formation by up to 33% after 48 h. Exogenous tyrosol appeared to have no effect, but scanning electron microscopy revealed that tyrosol stimulated hypha production during the early stages (1 to 6 h) of biofilm development. Experiments involving the simultaneous addition of tyrosol and farnesol at different concentrations suggested that the action of farnesol was dominant, and 48-h biofilms formed in the presence of both compounds consisted almost entirely of yeast cells. When biofilm supernatants were tested for their abilities to inhibit or enhance germ tube formation by planktonic cells, the results indicated that tyrosol activity exceeds that of farnesol after 14 h, but not after 24 h, and that farnesol activity increases significantly during the later stages (48 to 72 h) of biofilm development. Overall, our results support the conclusion that tyrosol acts as a quorum-sensing molecule for biofilms as well as for planktonic cells and that its action is most significant during the early and intermediate stages of biofilm formation.

Nanomaterials, today, are an integral part of our everyday lives, industrial processes and appliances. Biosynthesis, because of its environmental sustainability, is now becoming a hot topic. The biosynthesis of nanomaterials using plant phytochemicals enhances the nanomaterial’s biocompatibility and its compatibility with the environment too. Hence, forthe first time, this study uses Caralluma acutangula (CA) plant extracts to synthesize silver nanoparticles (CA-AgNPs) and characterize them using UV–visible spectroscopy, FTIR, Raman spectroscopy, XRD, TEM, TGA, SEM, EDX, zeta potential, and bandgap analysis. The particle size distributions of CA-AgNPs were observed to fall in the range of 2–6 nm predominantly using TEM images. High crystallinity % was calculated as 86.01 using XRD data. Extracted phytochemicals from CA were characterized and analyzed using GC-MS. The bandgap (Eg) of CA-AgNPs was calculated as 3.01 eV and zeta potential was found to be −16.1 mV. The biosynthesized CA-AgNPs were confirmed for their degradation efficiency of two toxic water pollutant dyes: Congo red, CR (95.24% degradation within 36 min), and methylene blue, MB (96.72% degradation within 32 min), in the presence of NaBH4. Different doses of CA-AgNPs and NaBH4 were checked for their chemical kinetics and rate constant analysis. The chemical kinetics were explored on the basis of integrated rate law model equations and confirmed as pseudo-zero-order reactionsfor CR and MB dyes. The rate constant ‘k’ for CR and MB was calculated as 0.0311 and 0.0431 mol.L−1.min−1, respectively.

The levels of four metals (Zn, Cu, Cd, and Pb) were evaluated in two fruit types (apricot and fig), a fruity vegetable (tomato), and three leafy vegetables (arugula, spinach, and lettuce) that are commonly grown and consumed in Aseer Region, Saudi Arabia. Flame atomic absorption spectrophotometry was employed for quantification. The quality of results was checked by a certified reference material (NIST SRM 1570a). Good recovery values in the range of 87-104% were achieved. Metals were quantified in washed and unwashed samples to evaluate the effect of washing. Statistically, no significant difference was noticed (p>0.05), except for Zn in arugula and Cu in apricot and spinach. The levels of metals found in the analyzed fruits and vegetables were in their normal ranges in crops and not posing any serious risks to the consumers in Aseer Region. The toxic elements Pb and Cd were well below the maximum levels set in the Saudi and international food standards. Zn and Cu levels were comparable to the ranges reported in worldwide previous studies.

Background: Myrtus communis is a typical plant of Mediterranean area. The different parts of this plant such as berries, branches, and leaves have been used worldwide as a traditional/folk medicine for the treatment of various ailments and diseases. Methods: Ethanolic leaf extract of the plant was prepared by Soxhlet extraction method. Zone of inhibition, minimum inhibitory concentration and minimal bactericidal concentration were determined by well diffusion method and microplate alamar blue assay. GC-MS analysis was carried out to identify the compounds present in the extract. Microscopy and ImageJ software were used respectively for morphology and cell-length measurements. GraphPad Prism was used for statistical analysis. Results: The ethanolic extract showed strong inhibitory effect against Gram-positive and acid-fast bacteria with significant inhibition-zone size (9-25 mm), MIC (4.87-78 μg/ml), as well as MBC (0.3-20 mg/ml). However, no effect was observed on the growth of Gram-negative bacteria. The growth inhibition was found to be associated with the damage of cell wall as the extract-treated cells were sensitive to cell wall-targeting antibiotics and displayed the cell wall damage-depicting morphological defects. GC-MS analysis confirmed the presence of novel compounds in addition to the most representative compounds of the essential oils/extracts of M. communis of other country origins. Conclusion: These results demonstrate that M. communis leaf extract could be the source of compounds to be used for the treatment of Gram-positive bacterial infections. This is the first report, which provides insights into the mechanism of action of the extract in inhibiting the growth of Gram-positive bacteria.