Understanding bacteriocin heterologous expression: A review.

Bacteriocins are a diverse group of ribosomally synthesised antimicrobial peptides/proteins that play an important role in self-defence. They are widely used as bio-preservatives and effective substitutes for disease eradication. They can be used in conjunction with or as an alternative to antibiotics to minimize the risk of resistance development. There are remarkably few reports indicating resistance to bacteriocins. Although there are many research reports that emphasise heterologous expression of bacteriocin, there are no convincing reports on the significant role that intrinsic and extrinsic factors play in overexpression. A coordinated and cooperative expression system works in concert with multiple genetic elements encoding native proteins, immunoproteins, exporters, transporters and enzymes involved in the post-translational modification of bacteriocins. The simplest way could be to utilise the existing E. coli expression system, which is conventional, widely used for heterologous expression and has been further extended for bacteriocin expression. In this article, we will review the intrinsic and extrinsic factors, advantages, disadvantages and major problems associated with bacteriocin overexpression in E. coli. Finally, we recommend the most effective strategies as well as numerous bacteriocin expression systems from E. coli, Lactococcus, Kluveromyces lactis, Saccharomyces cerevisiae and Pichia pastoris for their suitability for successful overexpression.

Acquiring bifidobacteria species from formula-fed and breast-fed newborns: identifying, quantifying and creating an antibiogram.

After examining the Bifidobacterium spp. population in faeces samples from breast-fed and formula-fed infants, an antibiogram was created. The prevalence of Bifidobacterium spp. in faeces was determined using common bacterial growth media, including Man Rogos Sharpe (MRS), Brain Heart Infusion (BHI), Luria Bertani (LB) broth and Bifidobacteria agar. According to the findings, formula-fed babies had a low population of Bifidobacterium spp. in their stools while breast-fed babies had a high population. By using phylogenetic analysis of the 16S rRNA and xfp (xylose/fructose 6-phosphate phosphoketolase) genes, and RFLP mapping of Bifidobacterium isolates, it was possible to identify a new and unique Bifidobacterium species. The intensity of the reddish brown colour produced during the F6PPK (fructose 6-phosphate phosphoketolase) assay is an accurate indicator of the proportion of various bifidobacteria present. Bifidobacteria agar media produced the greatest amounts of bifidobacteria diversity and recovery. Small (SCV) and Big colony variations (BCV) were formed during growth on different media. The various antibiotic MIC values changed depending on the use of different media, growth circumstances, bile salt treatment and low pH. The findings of this study demonstrate that test conditions also impact the diversity of microbiological conditions that distinguish between resistant and susceptible bacteria.