Recombinant Tandem Repeated Expression of S3 and SΔ3 Antimicrobial Peptides

Enzymatically Crafted Bacterial Cellulose Nanoparticles Functionalized With Antimicrobial Peptides: Toward Sustainable Antimicrobial Formulations

Although natural antimicrobial peptides (AMPs) are endowed with excellent antimicrobial properties, only a few of them have been successfully translated to the market so far. This is mainly due to their short half-life, to their high susceptibility to protease degradation, and to the lack of appropriate strategies for their efficient targeted delivery. Hence, the development of an effective system to deliver AMPs to the site of infection is urgent. The system here selected is represented by bacterial cellulose nanoparticles (BCNPs). Nanocellulose has recently emerged as one of the most promising "green" materials, attracting great attention due to its unique features, including biodegradability, sustainability, biocompatibility, and special physicochemical properties. To produce BCNPs, Komagataeibacter xylinus has been selected as host producing strain. Once obtained BC macrofibers, the production of BCNPs was set up by enzymatic hydrolysis using a commercial mixture of cellulases from Trichoderma reesei to develop a sustainable green biotechnological process. The storage stability of produced BCNPs has been also evaluated. Obtained BCNPs have been functionalized through non-covalent bindings with an antimicrobial peptide previously identified in human apolipoprotein B and found to be endowed with strong antimicrobial properties in in vitro analyses and with good biocompatibility profiles when analyzed on human skin cells. This opens interesting perspectives to the applicability of the developed system in several biotechnological fields.

Detection strategies of infectious diseases via peptide-based electrochemical biosensors

Infectious diseases have threatened human life for as long as humankind has existed. One of the most crucial aspects of fighting against these infections is diagnosis to prevent disease spread. However, traditional diagnostic methods prove insufficient and time-consuming in the face of a pandemic. Therefore, studies focusing on detecting viruses causing these diseases have increased, with a particular emphasis on developing rapid, accurate, specific, user-friendly, and portable electrochemical biosensor systems. Peptides are used integral components in biosensor fabrication for several reasons, including various and adaptable synthesis protocols, long-term stability, and specificity. Here, we discuss peptide-based electrochemical biosensor systems that have been developed over the last decade for the detection of infectious diseases. In contrast to other reports on peptide-based biosensors, we have emphasized the following points i) the synthesis methods of peptides for biosensor applications, ii) biosensor fabrication approaches of peptide-based electrochemical biosensor systems, iii) the comparison of electrochemical biosensors with other peptide-based biosensor systems and the advantages and limitations of electrochemical biosensors, iv) the pros and cons of peptides compared to other biorecognition molecules in the detection of infectious diseases, v) different perspectives for future studies with the shortcomings of the systems developed in the past decade.

Tight Junction Modulatory Fusion Peptide (ADT-6) Enhances GFP Protein Permeability through the Paracellular Pathway in Caco-2 Cell Lines: An In-Vitro Study

Background

The oral delivery of therapeutic peptides and proteins presents a significant challenge in pharmaceutical development due to barriers such as the intestinal epithelium and the blood-brain barrier (BBB). These barriers limit the passage of large, hydrophilic molecules through transcellular pathways and restrict paracellular transport due to intercellular tight junctions. This study investigates the potential of E- cadherin-modulating peptide, ADT-6, to improve the penetration of these therapeutic agents.

Methods

We constructed a fusion protein of ADT-6 and green fluorescent protein (GFP) to evaluate its activity and transport through the epithelial cells' paracellular pathway. Using Escherichia coli strains for expression, we cloned the GFP-ADT-6 construct, which provides a solid foundation for our study's methodology.

Results

Our molecular simulations showed that the linker between GFP and ADT-6 maintains the fusion protein's integrity and provides flexibility in receptor interaction. Permeability experiments revealed that ADT-6 markedly reduced transepithelial electrical resistance (TEER) and significantly increased GFP transfection in Caco-2 cell monolayers dose-dependently. Results of ELISA confirmed these findings, showing high GFP levels in the lower compartment of Transwell systems treated with GFP-ADT-6.

Conclusions

This study demonstrates the potential of ADT-6 to deliver proteins from the paracellular route, enhance the bioavailability of pharmaceutical drugs by altering cell-cell interactions, and provide new opportunities for oral drug delivery strategies.

Development strategies and application of antimicrobial peptides as future alternatives to in-feed antibiotics

The use of in-feed antibiotics has been widely restricted due to the significant environmental pollution and food safety concerns they have caused. Antimicrobial peptides (AMPs) have attracted widespread attention as potential future alternatives to in-feed antibiotics owing to their demonstrated antimicrobial activity and environment friendly characteristics. However, the challenges of weak bioactivity, immature stability, and low production yields of natural AMPs impede practical application in the feed industry. To address these problems, efforts have been made to develop strategies for approaching the AMPs with enhanced properties. Herein, we summarize approaches to improving the properties of AMPs as potential alternatives to in-feed antibiotics, mainly including optimization of structural parameters, sequence modification, selection of microbial hosts, fusion expression, and industrially fermentation control. Additionally, the potential for application of AMPs in animal husbandry is discussed. This comprehensive review lays a strong theoretical foundation for the development of in-feed AMPs to achieve the public health globally.

Effect of tandem repeats of antimicrobial peptide CC34 on production of target proteins and activity of Pichia pastoris

Antimicrobial peptides (AMPs) are attracting attention in the fields of medicine, food, and agriculture because of their broad-spectrum antibacterial properties, low resistance, and low-residue in the body. However, the low yield and instability of the prepared AMP drugs limit their application. In this study, we designed a tetramer of the AMP CC34, constructed and transfected two recombinant expression vectors with pGAPZαA containing a haploid CC34 and tetraploid CC34 (CC34-4js) into Pichia pastoris to explore the effect of biosynthesized peptides. The results showed that CC34 and CC34-4js expression levels were 648.2 and 1105.3 mg/L, respectively, in the fermentation supernatant of P. pastoris. The CC34-4js tetramer showed no antibacterial activity, could be cleaved to the monomer using formic acid, and the hemolytic rate of the polyploid was slightly lower than that of monomeric CC34. The average daily gain, average daily feed intake, feed conversion ratio and immune organ index of rats fed CC34 and CC34-4js showed no differences. In conclusion, CC34-4js exhibited a higher yield and lower hemolysis in P. pastoris than those of CC34. Finally, CC34 and CC34-4js enterokinase lysates showed similar antibacterial activity and both expressed peptides potentially improved the growth performance and organ indices of rats.

Efficient Delivery of Antimicrobial Peptides in an Innovative, Slow-Release Pharmacological Formulation

Both nanostructure and multivalency enhance the biological activities of antimicrobial peptides (AMPs), whose mechanism of action is cooperative. In addition, the efficacy of a particular AMP should benefit from a steady concentration at the local place of action and, therefore, from a slow release after a dynamic repository. In the context of emerging multi-resistant bacterial infections and the urgent need for novel and effective antimicrobial drugs, we tested these concepts through the engineering of four AMPs into supramolecular complexes as pharmacological entities. For that purpose, GWH1, T22, Pt5, and PaD, produced as GFP or human nidogen-based His-tagged fusion proteins, were engineered as self-assembling oligomeric nanoparticles ranging from 10 to 70 nm and further packaged into nanoparticle-leaking submicron granules. Since these materials slowly release functional nanoparticles during their time-sustained unpacking, they are suitable for use as drug depots in vivo. In this context, a particular AMP version (GWH1-NIDO-H6) was selected for in vivo validation in a zebrafish model of a complex bacterial infection. The GWH1-NIDO-H6-secreting protein granules are protective in zebrafish against infection by the multi-resistant bacterium Stenotrophomonas maltophilia, proving the potential of innovative formulations based on nanostructured and slowly released recombinant AMPs in the fight against bacterial infections.

Study of Antibacterial Chemical Substances and Molecular Investigation among Sulfamethoxazole-trimethoprim (SXT)-Resistant Escherichia coli Isolates

Background

Escherichia coli (E. coli) remains one of the leading agents of urinary tract infection (UTIs), it has become resistant to many drugs. Current work aimed to evaluate some chemical substances as antibacterial agents and molecular study of virulence factors associated with UTIs.

Methods

This work involved 133 urine specimens obtained from females' patients suffering from UTIs, Methods of well diffusion and disk diffusion were achieved to assay the effect of some chemical substances and antibiogram profiles toward Sulfamethoxazole-trimethoprim (SXT)-resistant E. coli respectively. Virulence genes were done based on the technique of Polymerase Chain Reaction (PCR).

Results

The results recorded 49/133 (36.84%) E. coli among women suffering UTIs, 28/49 (57.14%) were resistant to SXT drug. imipenem, meropenem, and nitrofurantoin were recorded more effectively. Chemicals substances at the concentration 0.3 (g/ml) recorded percentages of inhibition, reaching 9.143±1.442, 15.36±0.5914, and 21.82±0.8699 for NaHCO3, Ch4c, and Viroxide Super™ respectively. PCR demonstrated that 28/28 (100%) of SXT-resistant E. coli isolates were harbored Sul-2, FeoB and PapC genes, while 14/28 (50%), 15/28 (53.57%), 19/28 (67.85%) and 26/28 (92.85%) in U250 (pet), FumC, Sul-1 and IutA genes, respectively. Sul-3 gene was not observed.

Conclusion

Observed a high percentage of E. coli that were resistant to SXT drug, and having several virulence genes, poses a real threat, it requires a real pause to create substitutions to limit the spreading of this threat.