Background

/1. Bacterial conjugation and the idea.

Bacterial conjugation is a process in which bacteria recombinate gene through temporary communication of cells and transfer of genetic material. Bacterial conjugation is ubiquitous in the bacterial world, forms a potent force for gene dissemination and repair in the bacteria[1].

Based on the above characteristics, it is not difficult for us to think of using bacterial conjugation to make the target gene communicate among bacterial populations, so as to achieve the association of multiple factors. In order to preliminarily explore the feasibility of this idea, we adopted evolve the two peptide chains in bacteriocin PLNC8,to study their structural relevance.

/2.treatment of Helicobacter pylori

Helicobacter pylori is a spiral-shaped, micro-anaerobic, Gram-negative bacterium with very demanding growth conditions. Diseases caused by H. pylori infection include gastritis, peptic ulcer, lymphoproliferative gastric lymphoma, etc. Among them, gastric cancer has a poor prognosis[2]. Epidemiological surveys showed that the infection rate of H. pylori in the global natural population exceeds 50%. Poorer economic status, more crowded living, and lower education level are associated with higher infection rates of H. pylori[3].

Currently, the major challenge in the field of H. pylori infection is antibiotic resistance. in the anti-H. pylori research, some antibiotic therapies including new antibiotics or different combinations of classic antibiotics have been proposed. Treatments that have been proven to be more effective and safer in clinical practice include: Bismuth quadruple therapy(BQT)[4, 5], high dose dual therapy(HDDT)[6]and Triple-drug blister-packaged drugs including VPZ[7]

In addition, triple therapy with probiotic supplementation has been a recent research hotspot, and some regiments have been evaluated by a large number of studies, and good therapeutic effects have been achieved. Some studies have showed that S.boulardii supplementation on standard eradication therapy significantly increased H pylori eradication rates and reduced the incidence of total side effects and some gastrointestinal adverse effects during eradication therapy[8]. Triple therapy combined with Lactobacillus can increase H. pylori eradication rates as well as reduce the incidence of therapy-related diarrhea in children[9]. Triple therapy supplemented with Bacillus subtilis and Enterococcus faecium (BSEF) also plays an important role in protecting and restoring the gut microbiome[10].

/3. Therapeutic mechanisms of bacteriocins in Lactobacillus plantarum

In May 2022, a recent article pointed out that the bipeptide bacteriocin PLNC8 secreted from L. plantarum ZJ316 can disrupt the ability of H. pylori ZJC03 to alter the host environment and effectively prevent and control H. pylori infection[11]. The experiment showed that PLNC8 with high concentration has a larger range of inhibition on H. pylori than PLNC8 with low concentration, indicating that PLNC8 had the potential ability to inhibit H. pylori ZJC03 growth. There are many ways for PLNC8 to achieve this effect,but the specific mechanism is still unclear.