Peptide-Carbon Quantum Dots conjugate, Derived from Human Retinoic Acid Receptor Responder Protein 2, against Antibiotic-Resistant Gram Positive and Gram Negative Pathogenic Bacteria

Abstract

Antibiotic-resistant bacterial infections have become global issues for public health, which increases the utter need to develop alternatives to antibiotics. Here, the HSER (Homo sapiens retinoic acid receptor) peptide was designed from retinoic acid receptor responder protein 2 of Homo sapiens, and was conjugated with synthesized CQDs (carbon quantum dots) for enhanced antibacterial activity in combination, as individually they are not highly effective. The HSER–CQDs were characterized using spectrophotometer, HPLC coupled with electrospray-ionization quadrupole time-of-flight mass spectrometer (ESI–qTOF) mass spectrometer, zeta potential, zeta size, and FTIR. Thereafter, the antibacterial activity against Vancomycin-Resistant Staphylococcus aureus (VRSA) and Escherichia coli (carbapenem resistant) was studied using growth curve analysis, further supported by microscopic images showing the presence of cell debris and dead bacterial cells. The antibacterial mechanism of HSER–CQDs was observed to be via cell wall disruption and also interaction with gDNA (genomic DNA). Finally, toxicity test against normal human epithelial cells showed no toxicity, confirmed by microscopic analysis. Thus, the HSER–CQDs conjugate, having high stability and low toxicity with prominent antibacterial activity, can be used as a potential antibacterial agent.

Characterization and in vitro Analysis of Probiotic-Derived Peptides Against Multi Drug Resistance Bacterial Infections

“…To determine the susceptibility of bacterial cultures the standard broth micro-dilution method (European Committee on Antimicrobial Susceptibility Testing) was used and detection was done by an unaided eye. The PBDM peptides were incubated with bacterial cultures (OD 600 nm = 0.5 McF and final dilution 1:100 with MH medium) in different concentrations (50, 25, 20, 10, and 5 μg/mL) at 37°C for 24 h. The lowest inhibiting concentration of the antimicrobial agent against each bacterium is the MIC of the antimicrobial agent with respect to that bacterium ( Mazumdar et al, 2020 ).…”

“…The solutions with different concentration of antimicrobial agent were added to the microplate wells and mixed with the bacterial cultures (0.5 MacFarland with final dilution 1:100 using MH medium). Later the plate was used in Multiskan EX for 24 h and results were evaluated the next day after 24 h to obtain the growth curves ( Jelinkova et al, 2018a ; Mazumdar et al, 2020 ; Sur et al, 2020a ).…”

A Novel Ruthenium Based Coordination Compound Against Pathogenic Bacteria

“…The viability of S. aureus, VRSA (CCM 1767), and MRSA (ST239: SCCmecIIIA) ( Figure 8) and S. epidermidis ( Figure S14) after treatment with RU-S4 was observed by the LIVE/DEAD cell imaging assay [8,25,27]. The bacterial samples treated with RU-S4 showed considerably decreased cell count with green fluorescent, but a significant increase in number of dead cells with red fluorescence, whereas in the case of control bacterial cells, the number of green fluorescent cells were high with red fluorescence (Figure 8 and Figure S14).…”

“…0.6, WD 2.7-4mm, F.N. 22) and a mercury arc lamp X-cite 12 (120 W; Lumen Dynamics, Mississauga, ON, Canada) [8,18]. Four different kind of bacterial samples were used in this experiments VRSA (CCM 1767) MRSA (ST239: SCCmecIIIA), S. aureus (NCTC 8511) and hospital sample Staphylococcus epidermidis.…”

“…With the increasing mortality rate causing by antibiotic-resistant bacterial strains and with fewer appropriate treatment options for multi-drug resistant infections, currently, there is a necessity to investigate new candidates as potential alternative to antibiotics. In pursuit of new effective and non-cytotoxic antimicrobials, recent reports witnessed a rise in the usage of novel metal-based coordination compounds, nanoparticles (NPs) [7][8][9][10][11] or antimicrobial peptides as alternatives to existing antibiotics. It has been previously reported that transition metal-based coordination compounds and ligand-based coordination compounds were used as potential antimicrobial agents [7,[9][10][11][12].…”