Antimicrobial lipids loaded on lectin display reduced MIC, curtail pathogenesis and protect zebrafish from reinfection by immunomodulation.

Antibiotic resistance and re-emergence of highly resistant pathogens is a grave concern everywhere and this has consequences for all kinds of human activities. Herein, we showed that N-palmitoylethanolamine-derived cationic lipid (cN16E) had a lower minimum inhibitory concentration (MIC) against both Gram-positive and Gram-negative bacteria when it was loaded with Butea monosperma seed lectin (BMSL). The analysis using lectin-FITC conjugate labelling indicated that the improved antibacterial activity of BMSL conjugation was due to bacterial cell surface glycan recognition. Live and dead staining experiments revealed that the BMSL-cN16E conjugate (BcN16E) exerts antibacterial activity by damaging the bacterial membrane. BcN16E antimicrobial activity was demonstrated using an infected zebrafish animal model because humans have 70 % genetic similarity to zebrafish. BcN16E therapeutic potential was established successfully by rescuing fish infected with uropathogenic Escherichia coli (UPEC). Remarkably, the rescued infected fish treated with BcN16E prevented reinfection without further therapy, indicating BcN16E immunomodulatory potential. Thus, the study examined the expression of immune-related genes, including tnfα, ifnγ, il-1ß, il-4, il-10, tlr-2, etc. There was a significant elevation in the expression of all these genes compared to control and fish treated with BMSL or cN16E alone. Interestingly, when the rescued zebrafish were reinfected with the same pathogen, the levels of expression of these genes were many folds higher than seen earlier. Radial immune diffusion analyses (RIA) using zebrafish serum revealed antibody production during the initial infection and treatment. Interestingly, reinfected fish had significant immunoprecipitation in RIA, a feature absent in the groups treated with cN16E, BMSL, and control. These results clearly show that the BcN16E complex not only rescued infected zebrafish but also conferred long-lasting protection in terms of immunomodulation that protects against multiple reinfections. The findings support that BcN16E has immense potential as a novel immunostimulant for various biomedical applications.

Lectin-Fortified Cationic Copper Sulfide Nanoparticles Gain Dual Targeting Capabilities to Treat Carbapenem-Resistant Acinetobacter baumannii Infection.

Targeted drug delivery maximizes the chance to combat infection caused by drug-resistant pathogens. Herein, lectin-fortified cationic copper sulfide (cCuS) nanoparticles were suggested for targeted adhesion to bacterial membranes and to enforce bacterial death. Jacalin, a lectin from jackfruit seed, was conjugated to fluorescein isothiocyanate (FITC), and its ability to recognize bacterial cell surface glycans was demonstrated. Jacalin formed a noncovalent complex with cCuS, which was investigated by fluorescence quenching measurements. The data revealed that jacalin-cCuS (JcCuS) had a good affinity with an association constant K a of 2.27 (± 0.28) × 104 M-1. The resultant JcCuS complex displayed excellent anti-infective activity against carbapenem-resistant Acinetobacter baumannii (CRAB). The minimum inhibitory concentration (MIC) of cCuS was 62.5 µM, which was 2-fold lower than that of the broad-spectrum antibiotic ciprofloxacin. Interestingly, the MIC of JcCuS was reduced to 15.63 µM, which was attributed to jacalin fortification. The mechanistic study unveiled that JcCuS affected the membrane integrity, depolarized the inner membrane, and produced excess reactive oxygen species to combat CRAB at a lower concentration compared to cCuS. A. baumannii formed a biofilm more readily, which played a critical role in pathogenesis and resistance in clinical settings. JcCuS (3.91 µM) displayed stronger antibiofilm activity without affecting the metabolic viability of CRAB. Microscopy analyses confirmed the inhibition of biofilm formation and disruption of the mature biofilm upon treatment with JcCuS. Furthermore, JcCuS hindered pellicle formation and inhibited the biofilm-associated virulence factor of CRAB such as exopolysaccharide, cell surface hydrophobicity, swarming, and twitching mobility. The anti-infective potential of JcCuS was demonstrated by rescuing CRAB-infected zebrafish. The reduction in pathogen proliferation in muscle tissues was observed in the treated group, and the fish recovered from the infection and was restored to normal life within 12 h. The findings illustrate that lectin fortification offers a unique advantage in enhancing the therapeutic potential of antimicrobials against human pathogens of critical priority worldwide.

Phytolectin conjugated positively charged fatty acid amide impairs virulence factors and inhibits cross-kingdom biofilm formation of Candida albicans and uropathogenic Escherichia coli.

AIM: Polymicrobial biofilm encasing cross-kingdom micro-organisms are apparent in medicine, which imposes serious resistance to conventional antimicrobial treatment. The objective of the study was to explore Butea monosperma seed lectin (BMSL) conjugated antimicrobial lipid, 2-((N-[2-hydroxyethyl]palmitamido)methyl)-1-methylpyridin-1-ium iodide (cN16E) to inhibit mixed-species biofilm of uropathogenic Escherichia coli-Candida albicans. METHODS AND RESULTS: Antimicrobial activity and antibiofilm of cN16E and cN16E-BMSL conjugate (BcN16E) were analysed against single- and mixed microbial cultures. The minimum inhibitory concentration (MIC) indicates that the MIC of cN16E-BMSL conjugate (BcN16E) against cohabiting UPEC-C. albicans was eightfold lower than the cN16E. BcN16E affects membrane integrity to elicit antimicrobial activity. BcN16E inhibits the dual-species biofilm even with 16 times lower MIC of cN16E. BcN16E impairs the biofilm-associated virulence factors which include extracellular polysaccharides, cell surface hydrophobicity, swimming, swarming motilities, hyphal filamentous morphology, curli formation and haemolysin activity. As a proof of concept, we demonstrated BcN16E ability to inhibit dual-species biofilm formation on a urinary catheter. CONCLUSION: The study revealed that the BcN16E is better than cN16E in impairing biofilm-associated virulence factors and exerting antimicrobial activity. SIGNIFICANCE AND IMPACT OF THE STUDY: The findings emphasize that phytolectin has the potential to enhance the anti-virulence strategies of antimicrobials against cross-kingdom biofilm-related infections.

Synthesis of N-myristoyltaurine stabilized gold and silver nanoparticles: Assessment of their catalytic activity, antimicrobial effectiveness and toxicity in zebrafish.

In this paper, the application of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) synthesized using a biomimetic lipid, N-myristoyltaurine (N14T) was evaluated in common fields. The catalytic effectiveness of AgNPs and AuNPs was studied in the popular nanocatalyst reaction, nitroaromatic reduction, and dye degradation. Both NPs display catalytic activity in the nitroaromatic compound and organic dyes reduction reaction involving sodium borohydride and the rate constant is estimated as 10-3 s-1. Strikingly, the reaction initiation time (t0) and completion time (tc) differ significantly between AgNPs and AuNPs. Analyzing the reaction kinetic profile revealed that the reaction carried out with AuNPs showed a shorter t0 and tc, suggesting a better catalyst than AgNPs. In addition, the efficiency of the NPs was examined in Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) and Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa). In difference to the catalytic study, AuNPs display poor antibacterial activity. Whereas AgNPs kill the tested bacteria at 250 µM via disturbing bacterial membrane integrity and produce excess reactive oxygen species. The toxicology study carried out with zebrafish animal model reveals that both AgNPs and AuNPs are non-toxic. The findings suggest that each nanomaterial possesses unique physicochemical properties irrespective of stabilization with the same molecules.