Compact RNA editors with natural miniature Cas13j nucleases.

Clustered regularly interspaced short palindromic repeats-Cas13 effectors are used for RNA editing but the adeno-associated virus (AAV) packaging limitations because of their big sizes hinder their therapeutic application. Here we report the identification of the Cas13j family, with LepCas13j (529 aa) and ChiCas13j (424 aa) being the smallest and most highly efficient variants for RNA interference. The miniaturized Cas13j proteins enable the development of compact RNA base editors.

Nisin-relevant antimicrobial peptides: synthesis strategies and applications.

Small pentacyclic peptides, represented by nisin, have been successfully utilized as preservatives in the food industry and have evolved into a paradigm for understanding the genetic structure, expression, and control of genes created by lantibiotics. Due to the ever-increasing antibiotic resistance, nisin-relevant antimicrobial peptides have received much attention, which calls for a summarization of their synthesis, modification and applications. In this review, we first provided a timeline of select highlights in nisin biosynthesis and engineering.

Development of Base Editors for Simultaneously Editing Multiple Loci in .

serves as the most extensively studied model organism and an important dairy species. Though CRISPR-Cas9 systems have been developed for robust genetic manipulations, simultaneously editing multiple endogenous loci in is still challenging. Herein, we first report the development of a double-strand break-free, robust, multiloci editing system CRISPR-deaminase-assisted base editor (CRISPR-DBE), which comprises a cytidine (CRISPR-cDBE) and an adenosine deaminase-assisted base editor (CRISPR-aDBE).

LssR plays a positive regulatory role in acid and nisin tolerance response of Lactococcus lactis.

In Lactococcus lactis, different regulation mechanisms can be activated to overcome the effects of adverse environmental stresses. Here, a TetR family regulator LssR was demonstrated as a positive regulator in the activation of the mechanisms involved in acid and nisin tolerance of L. lactis.

Systems-Level Analysis of the Global Regulatory Mechanism of CodY in Lactococcus lactis Metabolism and Nisin Immunity Modulation.

Bacteria adapt to the constantly changing environment by regulating their metabolism. The global transcriptional regulator CodY is known to regulate metabolism in low-G+C Gram-positive bacteria. Systems-level identification of its direct targets by proteome and chromatin immunoprecipitation followed by sequencing (ChIP-seq) assays have rarely been reported.

d-Methionine and d-Phenylalanine Improve Lactococcus lactis F44 Acid Resistance and Nisin Yield by Governing Cell Wall Remodeling.

encounters various environmental challenges, especially acid stress, during its growth. The cell wall can maintain the integrity and shape of the cell under environmental stress, and d-amino acids play an important role in cell wall synthesis. Here, by analyzing the effects of 19 different d-amino acids on the physiology of F44, we found that exogenously supplied d-methionine and d-phenylalanine increased the nisin yield by 93.

The genome and transcriptome of Lactococcus lactis ssp. lactis F44 and G423: Insights into adaptation to the acidic environment.

Nisin, as a common green (environmentally friendly), nontoxic antibacterial peptide secreted by Lactococcus lactis, is widely used to prevent the decomposition of meat and dairy products and maintains relatively high stability at low pH. However, the growth of Lc. lactis is frequently inhibited by high lactic acid concentrations produced during fermentation.

A novel small RNA S042 increases acid tolerance in Lactococcus lactis F44.

Lactococcus lactis, a gram-positive bacterium, encounters various environmental stresses, especially acid stress, during fermentation. Small RNAs (sRNAs) that serve as regulators at post-transcriptional level play important roles in acid stress response. Here, a novel sRNA S042 was identified by RNA-Seq, RT-PCR and Northern blot.

The novel sRNA s015 improves nisin yield by increasing acid tolerance of Lactococcus lactis F44.

Nisin, a polycyclic antibacterial peptide produced by Lactococcus lactis, is stable at low pH. Improving the acid tolerance of L. lactis could thus enhance nisin yield.

"Perfect" designer chromosome V and behavior of a ring derivative.

Perfect matching of an assembled physical sequence to a specified designed sequence is crucial to verify design principles in genome synthesis. We designed and de novo synthesized 536,024-base pair chromosome synV in the "Build-A-Genome China" course. We corrected an initial isolate of synV to perfectly match the designed sequence using integrative cotransformation and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9)-mediated editing in 22 steps; synV strains exhibit high fitness under a variety of culture conditions, compared with that of wild-type V strains.