The large consumption of non-renewable fossil fuels has brought about energy depletion and environmental pollution, spawning the production of renewable biofuels, an important alternative to alleviate the energy crisis effectively. As one of the ideal types of biofuel, bioethanol synthesis in Saccharomyces cerevisiae has attracted much attention. S. cerevisiae has been developed as essential chassis cells with high efficiency for bioethanol synthesis on account of many advantages. This study systematically summarized the preponderance of S. cerevisiae in biosynthesis. It objectively stated the research strategies of bioethanol synthesis based on S. cerevisiae and the existing bottleneck problems. This study further proposed reasonable prospects for bioethanol synthesis by S. cerevisiae, attempting to provide alternative research strategies.

Cordyceps cicadae (C. cicadae) is an important edible medicinal fungus; however, owing to its wild growth and lack of genome annotation, construction of a stable genetic transformation system in C. cicadae is greatly limited, impeding the extensive exploitation of C. cicadae in industry. Here, we successfully established an efficient plasmid transformation method within protoplasts of C. cicadae by PEG mediation using pCas9-EGFP as a marker plasmid. In order to overcome low transformation efficiency and acquire sufficient protoplasts for transformation, the influence of enzyme species, enzymatic hydrolysis time, enzymatic hydrolysis temperature, and fungal age on protoplast preparation were analyzed sequentially, and the optimal conditions for protoplast preparation were determined as follows: 2-day-old C. cicadae mycelia with 1.5% lywallzyme hydrolysis at 34 °C for 5 h. Our results indicate that no less than 5.1 × 10⁷ CFU/mL protoplasts could be acquired. Additionally, five osmotic pressure stabilizers including potassium chloride (KCl), sodium chloride (NaCl), glucose, mannitol, and sucrose were employed to enhance the regeneration of protoplasts, among which sucrose exhibited the highest regeneration rate of 10.43%. The transformation efficiency of plasmid was 37.3 CFU/µg DNA. On this basis, a genetic transformation method was successfully constructed, laying the foundation for further gene editing and metabolic engineering of C. cicadae.

Bacterial non-coding RNAs (ncRNAs) play important regulatory roles in various physiological metabolic pathways. In this study, a novel ncRNA CsiR (ciprofloxacin stress-induced ncRNA) involved in the regulation of ciprofloxacin resistance in the foodborne multidrug-resistant Proteus vulgaris (P. vulgaris) strain P3M was identified. The survival rate of the CsiR-deficient strain was higher than that of the wild-type strain P3M under the ciprofloxacin treatment condition, indicating that CsiR played a negative regulatory role, and its target gene emrB was identified through further target prediction, quantitative real-time PCR (qRT-PCR), and microscale thermophoresis (MST). Further studies showed that the interaction between CsiR and emrB mRNA affected the stability of the latter at the post-transcriptional level to a large degree, and ultimately affected the ciprofloxacin resistance of P3M. Notably, the base-pairing sites between CsiR and emrB mRNAs were highly conserved in other sequenced P. vulgaris strains, suggesting that this regulatory mechanism may be ubiquitous in this species. To the best of our knowledge, this is the first identification of a novel ncRNA involved in the regulation of ciprofloxacin resistance in P. vulgaris species, which lays a solid foundation for comprehensively expounding the antibiotic resistance mechanism of P. vulgaris.

Proteus vulgaris is an emerging multidrug-resistant (MDR) foodborne pathogen that poses a significant threat to food safety and public health, particularly in aquaculture systems where antibiotic use may drive resistance development. Despite its increasing clinical importance, the genomic mechanisms underlying antimicrobial resistance (AMR) and virulence transmission in foodborne Proteus vulgaris remain poorly understood, representing a critical knowledge gap in One Health frameworks. To investigate its AMR and virulence transmission mechanisms, we analyzed strain P3M from Penaeus vannamei intestines through genomic island (GI) prediction and comparative genomics. Our study provides the first comprehensive characterization of mobile genetic elements in aquaculture-derived Proteus vulgaris, identifying two virulence-associated GIs (GI12/GI15 containing 25/6 virulence genes) and three AMR-linked GIs (GI7/GI13/GI16 carrying 1/1/5 antibiotic resistance genes (ARGs)), along with a potentially mobile ARG cluster flanked by IS elements (tnpA-tnpB), suggesting horizontal gene transfer capability. These findings elucidate previously undocumented genomic mechanisms of AMR and virulence dissemination in Proteus vulgaris, establishing critical insights for developing One Health strategies to combat antimicrobial resistance and virulence in foodborne pathogens.

Polymyxin, known as the “last line of defense” against bacterial infection, exerts a significant inhibitory effect on a wide range of Gram-negative pathogenic bacteria. The presence of strains, specifically Proteus vulgaris species, displaying intrinsic polymyxin resistance poses significant challenges to current clinical treatment. However, the underlying mechanism responsible for this intrinsic resistance remains unclear. Bacterial non-coding RNAs (ncRNAs) are abundant in genomes and have been demonstrated to have significant regulatory roles in antibiotic resistance across various bacterial species. However, it remains to be determined whether ncRNAs in Proteus vulgaris can regulate intrinsic polymyxin resistance. This study focused on investigating the foodborne Proteus vulgaris strain P3M and its intrinsic polymyxin resistance regulation mediated by ncRNAs. Through a combination of bioinformatics analysis, mutant construction, and phenotypic experimental verification, we successfully identified the ncRNAs involved and their potential target genes. These findings serve as an essential foundation for the precise identification of ncRNAs participating in the intricate regulation process of polymyxin resistance. Additionally, this study offers valuable insights into the efficient screening of bacterial ncRNAs that contribute positively to antibiotic resistance regulation.