Project description:The effectiveness of antibacterial agents is strongly influenced by its antibacterial mechanism, which, in turn, is dependent on the agent’s topological structure. In addition to oxidative stress (especially caused by reactive oxygen species), known to be a key mechanism for 2D phosphorene structures, physical penetration of bacterial cell membranes is predicted for violet phosphorene nanosheets. In this study, we demonstrate that violet phosphorus (VP) and its exfoliated product, violet phosphorene nanosheets (VPNS), have superior antibacterial capability against pathogens.A series of antibacterial tests and theoretical calculations show that VPNS can inactivate >99.9% of two common pathogens (Escherichia coli and Staphylococcus aureus) and >99% of two “superbugs” (i.e., antibiotic-resistant bacteria, Escherichia coli pUC19 and methicillin-resistant Staphylococcus aureus) via oxidative stress combined with cell membrane penetration by VPNS Moreover, VPNS have higher antibacterial activity than black phosphorene nanosheets in vitro and in vivo. We believe VPNS as special rigidly structured nanoagents have great potential for eradicating pathogens.
Project description:Current clinical antibiotics are largely broad-spectrum agents that promote intestinal dysbiosis and colonisation of Enterobacteriaceae, which are often drug-resistant. Indeed, dysbiosis creates an ideal niche for adherent-invasive Escherichia coli (AIEC) in patients with inflammatory bowel disease (IBD). There is an urgent and unmet need for novel narrow-spectrum and microbiome-sparing antibiotics. Here, we screened >10,000 molecules for antibacterial activity against AIEC and discovered enterololin, an antibacterial compound with targeted activity against Enterobacteriaceae species. Molecular substructure- and deep learning-guided mechanism of action investigations revealed that enterololin perturbs lipoprotein trafficking through a mechanism involving the LolCDE complex. Moreover, enterololin can suppress an AIEC infection in mouse models, while largely preserving the overall microbiome composition. This work highlights the utility of deep learning methods for predicting molecular interactions, thereby accelerating mechanism of action elucidation of novel molecules, and identifies a promising Enterobacteriaceae-specific antibacterial candidate for further development to treat challenging infections in IBD patients.
Project description:Chinese alligator (Alligator sinensis) is one of the rarest endangered reptiles found in China and possesses strong immune potential. This study tested the antibacterial ability of Chinese alligator serum (CAS) against Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa and analyzed the underlying mechanisms. Results showed that the CAS had a marked antibacterial effect on K. pneumoniae, E. coli, and P. aeruginosa. However, S. aureus was only mildly affected, and this effect disappeared when incubated with Protease K. The serum proteome revealed that the antibacterial ability of CAS was produced by interactions between various proteins and that the complement proteins played a major antibacterial role. Furthermore, the prediction of the structure and function of complement component 3 revealed eight potential protein binding sites and one nucleic acid binding site that were likely related to the broad-spectrum antibacterial ability of this serum. This study provided evidence that CAS elicits significant antibacterial effects against some pathogens and provides the basis for further development of novel antibacterial drugs.
Project description:Systemic inflammation like in sepsis is still lacking specific diagnostic markers and effective therapeutics. The first line of defense against intruding pathogens and endogenous damage signals is pattern recognition by e.g., complement and Toll-like receptors (TLR). Combined inhibition of a key complement component (C3 and C5) and TLR-co-receptor CD14 has been shown to attenuate certain systemic inflammatory responses. Using DNA microarray and gene annotation analyses, we aimed to decipher the effect of combined inhibition of C3 and CD14 on the transcriptional response to bacterial challenge in human whole blood. Importantly, combined inhibition reversed the transcriptional changes of 70% of the 2335 genes which significantly responded to heat-inactivated Escherichia coli by on average 80%. Single inhibition was less efficient (p<0.001) but revealed a suppressive effect of C3 on 21% of the responding genes which was partially counteracted by CD14. Furthermore, CD14 dependency of the Escherichia coli-induced response was increased in C5-deficient compared to C5-sufficient blood. The observed crucial distinct and synergistic roles for complement and CD14 on the transcriptional level correspond to their broad impact on the inflammatory response in human blood, and their combined inhibition may become inevitable in the early treatment of acute systemic inflammation.
Project description:This study delves into the enzymatic hydrolysis of low-cost salted jellyfish (Rhopilema hispidum) by-products using pepsin to generate bioactive peptides that possess multifunctional properties. The resulting hydrolysates were purified and evaluated for their antibacterial activity against Escherichia coli.
Project description:Transcriptional profiling of Escherichia coli TB1 cells under (-)-Roemerine treatment. The genome reprograming in the bacterial cells at transcription level was analyzed through treatment of the bacteria with plant-derived alkaloid, (-)-Roemerine, to elucidate the response of bacteria to the antibacterial drug.
Project description:The current study deals to decipher the antibacterial mechanism of lysozyme coated silver nanoparticles (L-Ag NPs) (coated with lysozyme) against a Gram negative modal organism Escherichia coli K12 (MTCC 1302). Hence, the whole transcriptome profiling of E. coli K12 was done by exposing it to the MIC75 concentration of L-Ag NPs for 5 and 30 min., by RNA sequencing (RNAseq) analysis. The obtained results were utilized to understand all the metabolic pathways, signaling and molecular functions in bacterial cells under the stress of L-Ag NPs. RNAseq showed a high number of total reads along with significant ratio of high-quality reads, which confirmed the excellent quality and quantity of the obtained RNAseq data. Controlled release of ions from the surface of L-Ag NPs allowed the bacterial cells to function normally till the accumulation of threshold amount of silver ions which triggered the action of defence system, thus, reducing the chances of resistance development in bacteria. In long term, such treatment may force the bacterial machinery to induce changes in their genome to counteract the situation and develop resistance against silver ions, similar to the well-known antibiotic resistance problem. The obtained results advocate that L-Ag NPs can be used as effective antibacterial agent.
Project description:Although DNA motifs recognized by the transcription factors (TFs) have been determined, challenges remain in probing in vivo architecture of TF-DNA complexes on a genome-wide scale. Here, we show in vivo architecture of Escherichia coli arginine repressor (ArgR)-DNA complexes using chromatin immunoprecipitation coupled with sequencing (ChIP-exo). The identified 62 ArgR-binding loci were classified into three groups, comprised of single, double, and triple peak-pairs, respectively. Each peak-pair has unique 93 bp-long (±2 bp) ArgR-binding sequence containing two ARG boxes (39 bp) and residual sequence. Moreover, the peak-pairs provided the three ArgR-binding modes defined by the position of the two ARG boxes, indicating that the formation of DNA bending apparently centered between the pair of ARG boxes facilitates the non-specific contacts between ArgR subunits and the residual sequences. Thus, our data postulate the in vivo architecture of ArgR-DNA complexes to understand its transcription regulatory mechanism. ChIP-exo profiles of ArgR (+Arginine) and ArgR (-Arginine) were generated by deep sequencing in duplicates using Illumina MiSeq.
Project description:Type I interferons were discovered as the primary antiviral cytokines and are now known to serve critical functions in host defense against bacterial pathogens. Accordingly, established mediators of interferon antiviral activity may mediate previously unrecognized antibacterial functions. RNase-L is the terminal component of an RNA decay pathway that is an important mediator of interferon-induced antiviral activity. Here we identify a novel role for RNase-L in the host antibacterial response. RNase-L-/- mice exhibited a dramatic increase in mortality following challenge with Bacillus anthracis and Escherichia coli; this increased susceptibility was due to a compromised immune response resulting in increased bacterial load. Investigation of the mechanisms of RNase-L antibacterial activity indicated that RNase-L is required for the optimal induction of proinflammatory cytokines that play essential roles in host defense from bacterial pathogens. RNase-L also regulated the expression of the endolysosomal protease, cathepsin-E, and endosome-associated activities, that function to eliminate internalized bacteria and may contribute to RNase-L antimicrobial action. Our results reveal a unique role for RNase-L in the antibacterial response that is mediated through multiple mechanisms. As a regulator of fundamental components of the innate immune response, RNase-L represents a viable therapeutic target to augment host defense against diverse microbial pathogens. two strains: wildtype and knockout, three time points: untreated, 2hours, and 8hours. three replication for each group. Totally 18 samples.