No abstract

No abstract

Biodegradation is a sustainable green strategy that gives the opportunity for remediation of water contaminated with petroleum products. In this study, 12 bacterial isolates were recovered from River Nile, Egypt and screened for their potential to degrade a mixture of paraffinic petroleum crude oil. The most promising isolate was identified according to 16S rRNA sequencing as Janibacter terrae strain S1N1 (GenBank accession No. KX570955.1). In order to boost the biodegradation efficiency, the bacterial suspension was photostimulated by exposure to different irradiation doses using a low-power helium–neon (He–Ne) laser (λ = 632.8 nm). Maximum biodegradation was achieved after 4 min of exposure (134.07 J cm –2 ) at optimized pH value (6) and temperature (35 °C). The gas chromatography–mass spectrometry (GC-MS) analysis revealed the biodegradation of 96.5% of the substrate after only 48 h of incubation. The n-C 17 /Pr and n-C 18 /Ph ratios indicated a preferential biodegradation of iso-paraffines over normal ones. Meanwhile, pristane/phytane (Pr/Ph) ratios were indicative of selective biodegradation for pristane. The carbon preference index (CPI) was nearly around unity indicating the ability of Janibacter terrae to attack the odd and even n -alkanes simultaneously. These results support the superiority of irradiated bacteria in optimizing the biodegradation efficiency and shortening the time of treatment, thus proposing an eco-friendly technique in water bioremediation programs.

The discovery of new inhibitory natural compounds targeting bacterial virulence is an important strategy to overcome resistance to traditional antibiotics, in the present study the antibacterial activity of micro and nano curcumin suspensions was investigated against four predominant bacterial pathogens, including E. coli, P. aeruginosa, S. aureus, and B. subtilus. In vitro antibacterial assay indicated that nanocurcumin suspension displayed significant results. Molecular docking analysis was conducted to confirm the impact of curcumin on the quorum-sensing pathway in all bacterial groups, also the pharmacokinetic properties revealed that curcumin can be classified as a drug like compound. Wound model was employed for wound healing activity in four equal groups of male albino rats, their dorsal thoracic central regions were wounded with surgical blades. The individual groups were treated daily with 5% W/W of micro and nano curcumin lotions and soframycin ointment. Topical application of nanocurcumin lotion showed marked reduction on wound area compared to the control group as wound healing reached 98.8% on the 15th of injury. ANOVA test was performed to assess the significance of mean differences. The findings from this research indicate that nanocurcumin is effective in inhibiting bacterial infections and faster the process of wound healing.

Repurposing natural compounds as inhibitory targets to combat bacterial virulence is an important potential strategy to overcome resistance to traditional antibiotics, in the present study, the antibacterial activity of micro-curcumin and nano-sized curcumin was investigated against four predominant bacterial pathogens, namely, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis. Curcumin bactericidal susceptibility could be summarized as the order, P. aeruginosa > B. subtilis > S. aureus > E. coli. Molecular docking analysis was conducted to confirm the impact of curcumin on the most vital and positively identified quorum-sensing pathway signaling proteins SecA-SecY, LsrR, PqsR (MvfR), AgrA which act as key players in the bacterial communication systems. The in silico physicochemical properties revealed that curcumin as a nutraceutical can be classified as a drug-like compound. An in vivo infected wound model was employed in four groups of albino rats. Topical application of nano-curcumin lotion showed a marked reduction in wound area (98.8%) as well as nearly 100% reduction in total bacterial viable count compared to the control group, on the fifteenth day post-treatment post-injury. The obtained data suggested that curcumin nanoparticles exhibited superior antibacterial activity and may possess clinical utility as a novel topical antimicrobial and wound healing agent.