Frontiers in Microbiology最新文献

Mustard (Brassica juncea L.), rich in vitamins, minerals, and glucosinolates, yields fermented products valued for their distinct flavor and health benefits, particularly across East and Southeast Asia. The fermentation process is primarily driven by a complex microbial community dominated by lactic acid bacteria (LAB) such as Lactobacillus fermentum, Lactobacillus pentosus, and Lactobacillus plantarum. These microbes metabolize substrates to generate organic acids, volatile compounds, and free amino acids, which collectively shape the product's flavor and sensory quality. This review systematically summarizes recent progress in mustard fermentation, focusing on: the composition, succession, and function of microbial communities across different regions and fermentation stages and their influence on fermentation characteristics; the regulatory effects of key processing parameters-including fermentation vessel, temperature, and salt concentration-on microbial ecology, metabolic pathways, and final product quality; the chemical basis of taste attributes such as sourness, umami, bitterness, and pungency alongside the formation and evolution of aroma compounds during fermentation, and their links to microbial metabolism and biochemical pathways like glycolysis and the tricarboxylic acid cycle; and the formation patterns of potential risk factors such as biogenic amines and nitrite during fermentation, along with strategies to control their levels through process optimization and starter culture selection. Finally, future research directions are outlined, emphasizing the integration of omics and synthetic biology technologies to elucidate flavor formation mechanisms, develop stable starter cultures, and establish standardized processes. These advances aim to achieve consistent flavor, improved quality, and safe production of fermented mustard products, supporting the sustainable development of the industry.

Introduction: Plasma-treated aqueous solutions have proven effective for the inactivation of bacteria and even dormant spores. However, reported efficacies vary considerably across setups and experimental conditions. Consequently, different reactive species formed during treatment and their specific reaction kinetics are considered to be responsible. Their individual contribution to microbial inactivation depends on a thorough understanding of the underlying chemical processes. We found that the buffer capacity of an aqueous solution strongly influences the concentrations of reactive species required for effective microbial inactivation. Conversely, the temporal evolution of reactions allows for the optimization of bactericidal and sporicidal efficacy.

Methods: Using time-resolved in situ UV spectrometry, formation and degradation processes of significant reactive oxygen and nitrogen species (RONS) were observed and analyzed during and after plasma treatment.

Results: The availability and concentration of peroxynitrous acid (ONOOH) proved crucial for the antimicrobial activity of the liquid. ONOOH generation depends on hydrogen peroxide (H₂O₂) and nitrite (NO₂ ^-), both supplied by the plasma exposure, and eventually decays to nitrate (NO₃ ^-), which remains in solution. Experimental data showed that liquids with higher buffer capacity accumulated higher concentrations of H₂O₂ and NO₂ ^- during plasma exposure, enabling continued ONOOH production even after partial buffer depletion. Concurrently, the solutions acidified progressively. Bacteria, either vegetative cells or dormant spores, were added to the solutions at different time points during the process, and inactivation was monitored in relation to RONS concentrations. The observed antimicrobial efficacy correlated directly with ONOOH concentration, which can be adjusted via the buffer capacity of the medium. This resulted in a 3.83-log₁₀ reduction of Bacillus atrophaeus spores within 90 min and a 5.78-log₁₀ reduction of Escherichia coli within 45 min.

Discussion: Simulations reproduced these experimental trends, confirming three distinct kinetic regimes: a pre-reaction window (before ONOOH formation), a main reaction window (dominated by ONOOH production), and a post-reaction window (defined by decomposition).

The use of native microorganisms in craft beer and wine production represents a transformative approach that significantly enhances quality, sensorial complexity, and authenticity of the beverages. Integrating these microorganisms facilitates terroir expression, reduces dependence on commercial monocultures, and promotes sustainability by preserving native microbial biodiversity, which is vital to the identity of fermented craft beverages. This review analyzes the main roles of native yeasts, including Saccharomyces cerevisiae, Brettanomyces bruxellensis, Lachancea thermotolerans, Torulaspora delbrueckii, Pichia kudriavzevii, and Hanseniaspora spp., in shaping the biochemical and sensory profiles of craft beer and wine. It also provides a summary of the functions of lactic acid bacteria (LAB; Lactobacillus, Leuconostoc, Pediococcus, Oenococcus) in malolactic fermentation and flavor development, as well as the effects of acetic acid bacteria (AAB; Acetobacter, Gluconobacter) on oxidative complexity in select beverage styles. This work also highlights the use of mixed inoculation strategies and targeted strain selection to optimize fermentation kinetics, stress tolerance, and enzymatic activities, particularly those that enhance the liberation of aroma precursors. Additionally, challenges such as fermentation consistency, microbiological safety, and the need for standardized processes are also discussed. This framework provides essential insights to researchers and craft producers seeking innovation, product differentiation, and cultural preservation in the craft brewing and winemaking sectors, supporting regional economies and global biodiversity conservation through the scientifically grounded exploitation of native microorganisms.

Introduction: Biological ageing is associated with physiological changes, including alterations in the gut microbiota. Lactobacilli may contribute to host health and longevity, yet their composition and functional properties in centenarians remain poorly characterized. The present study aimed to compare cultured intestinal lactobacilli from centenarians and young adults and to identify strains with potential probiotic properties.

Methods: Fecal samples were obtained from centenarians (n = 25) and young adults (n = 25). Lactobacilli were isolated using culture-based methods and identified to the species level. Antibiotic susceptibility testing was performed for all isolates. Biochemical and metabolic properties of antibiotic-sensitive strains were determined.

Results: Twenty Lactobacillus species were identified. Six species were shared between groups, 12 were unique to centenarians, and two to young adults. Although overall Lactobacillaceae abundance was similar, centenarians showed greater species richness and a higher relative proportion of lactobacilli. Isolates from centenarians exhibited distinct carbohydrate fermentation patterns and metabolic profiles, including higher levels of acylcarnitines, arachidonic acid, and selected bile acids.

Discussion: Lactobacilli isolated from centenarian demonstrate distinct compositional and metabolic characteristics compared with those from young adults. These differences may reflect functional adaptations potentially relevant to healthy ageing and could inform the selection of candidate strains for future probiotic development.

[This corrects the article DOI: 10.3389/fmicb.2026.1791792.].

[This corrects the article DOI: 10.3389/fmicb.2026.1741287.].

The phenomenon of bacterial resistance has emerged as a significant challenge to global public health. Due to the increasing prevalence of antibiotic resistance, there has been interest in developing antimicrobial peptides (AMPs) as alternative antimicrobial therapies. However, AMPs resistance is not uncommon; it is simply subject to complex ecological and physiological limitations. While AMPs demonstrate potent antimicrobial activity in experimental and preclinical studies, their clinical efficacy remains limited. This review mainly summarizes the two methods of peptide hybridization and conjugation to combat drug-resistant bacteria. Hybridization has given AMPs new vitality, which overall enhance their antimicrobial spectrum, reduce toxicity, and enhance the bactericidal effect on drug-resistant strains. We also reviewed the conjugation of AMPs with various active molecules, such as antibiotics, antibodies, fatty acids, photosensitizers, phosphodiester oligomers, and nanoparticles. This review provides ideas for the design of hybrid peptides and coupled peptides in the future, and these AMPs have been shown to have an effect on drug-resistant strains after hybridization or coupling, thereby making the originally ineffective AMPs regain sensitivity. The transformation of natural AMPs has been effective in the laboratory to some extent, and give it clinical exploration value. Their clinical performance still falls short of that of conventional antibiotics due to challenges related to pharmacokinetics, safety, and reduced activity under clinically relevant conditions. To break through the bottleneck of clinical transformation of AMPs, it is necessary to continue to deepen multi-dimensional research on their physicochemical properties and make good use of artificial intelligence technology for intelligent design and high-throughput verification of hybrid peptides or conjugated peptides.

This study combined in vitro and in vivo experiments to evaluate the effects of three Lactobacillus plantarum strains (AP 6-5, 18-5-5, and Y2-2-3) on rumen fermentation, microbiota composition, and productive performance in lactating Holstein cows. In the in vitro trial, rumen fluid from three fistulated cows was incubated with TMR substrate supplemented with each strain (1 × 10⁷ CFU/mL) at 39 °C for 24 h. Compared with the CON, strains AP 6-5 and 18-5-5 reduced ruminal lactate and acetate concentrations, and strain 18-5-5 further decreased microbial crude protein (MCP). In the in vivo trial, forty-four cows were randomly assigned to four groups: a control (CON) and three treatment groups receiving 5 × 10¹⁰ CFU/d of strains AP 6-5 (AJT), 18-5-5 (NM), or Y2-2-3 (LP42) for 28 days after a 7-day adaptation. The NM group showed the highest DMI, milk yield, and lactose content, while the LP42 group had higher valeric acid concentration and fecal pH. Rumen microbiota analysis indicated enrichment of pathways related to carbohydrate utilization (NM) and protein metabolism (LP42). Overall, supplementation with L. plantarum, particularly strain 18-5-5, improved nutrient intake, milk production, and rumen microbial function in lactating cows.

[This corrects the article DOI: 10.3389/fmicb.2026.1741783.].

The gut microbiota plays a crucial role in human health and the progression of diseases. As key mediators of the interactions between gut microbiota and host diseases, metabolite changes have a significant influence on disease development and progression. However, without experimental validation by metabolomics, identifying the level of metabolite changes in specific diseases remains challenging. For this reason, we devised a scoring function to quantitatively estimate metabolite changes across disease phenotypes by integrating changes in the relative abundance of gut microbes owning these metabolites, and hereby developed the online repository to reserve these associations of metabolites and diseases. The consequent GMMAD with v2.0 currently contains 83 diseases and 6966 metabolites. Among them, 85,136 associations are of statistical significance (paired-sample t-test, p-value < 0.05 and FDR < 0.1). Notably, the scoring function showed 84.06% consistency with experimentally validated disease-metabolite associations, outperforming the prior semi-qualitative method (72.5%). Aided by this resource, we identified 130 beneficial metabolites across 27 diseases. Among them, literature supports that 48 could ameliorate the disease status in animals or clinical trials. We listed these 48 promising drug molecules on the website. Furthermore, we constructed a metabolite-gene association network and provided information on the origins of metabolites. All the metabolite-associated information would help researchers reveal the mechanisms of how gut microbes regulate disease progression and guide drug development. The GMMAD v2.0 is freely accessible at http://gepa.org.cn/GMMAD2/.