Aerobic adaptation and metabolic dynamics of DSM 20271: insights from comparative transcriptomics and surfaceome analysis.

Unlabelled: () DSM 20271 is a bacterium known for its ability to thrive in diverse environments and to produce vitamin B12. Despite its anaerobic preference, recent studies have elucidated its ability to prosper in the presence of oxygen, prompting a deeper exploration of its physiology under aerobic conditions. Here, we investigated the response of DSM 20271 to aerobic growth by employing comparative transcriptomic and surfaceome analyses alongside metabolite profiling.

Revised whole genome and DNA methylome of type strain ATCC 927.

, a slow-growing Actinobacterium, typically induces tuberculosis-like disease in fish. Here, we report a new reference sequence for ATCC 927, along with its DNA methylome. This aims to maximize the research potential of this type strain and facilitates investigations into the pathomechanisms of human tuberculosis.

Synthesis and Biological Evaluation of New Quinoline and Anthranilic Acid Derivatives as Potential Quorum Sensing Inhibitors.

Inhibiting quorum sensing (QS), a central communication system, is a promising strategy to combat bacterial pathogens without antibiotics. Here, we designed novel hybrid compounds targeting the PQS ( quinolone signal)-dependent quorum sensing (QS) of that is one of the multidrug-resistant and highly virulent pathogens with urgent need of new antibacterial strategies. We synthesized 12 compounds using standard procedures to combine halogen-substituted anthranilic acids with 4-(2-aminoethyl/4-aminobuthyl)amino-7-chloroquinoline, linked via 1,3,4-oxadiazole.

Food-Grade Bacteria Combat Pathogens by Blocking AHL-Mediated Quorum Sensing and Biofilm Formation.

Disrupting bacterial quorum sensing (QS) signaling is a promising strategy to combat pathogenic biofilms without the development of antibiotic resistance. Here, we report that food-associated bacteria can interfere with the biofilm formation of a Gram-negative pathogenic bacterium by targeting its AHL (acyl-homoserine lactone) QS system. This was demonstrated by screening metabolic end-products of different lactobacilli and propionibacteria using Gram-negative and biofilm-forming as the QS reporter and our anti-QS microscale screening platform with necessary modifications.

Label-free quantitative proteomics and immunoblotting identifies immunoreactive and other excretory-secretory (E/S) proteins of .

is a common tapeworm in horses causing colic and even mortalities. Current diagnostic tests to detect infections have their limitations and an improved method is needed. Immunoreactive excretory/secretory proteins (E/S proteome) of this parasite can provide promising candidates for diagnostic tests.

Anthranilamides with quinoline and β-carboline scaffolds: design, synthesis, and biological activity.

In the present study, we report the design and synthesis of novel amide-type hybrid molecules based on anthranilic acid and quinoline or β-carboline heterocyclic scaffolds. Three types of biological screenings were performed: (i) in vitro antiproliferative screening against a panel of solid tumor and leukemia cell lines, (ii) antiviral screening against several RNA viruses, and (iii) anti-quorum sensing screening using gram-negative Chromobacterium violaceum as the reporter strain. Antiproliferative screening revealed a high activity of several compounds.

Bioaccessibility of vitamin B12 synthesized by and from products made with fermented wheat bran extract.

The bioaccessibility of vitamin B12 (B12) in plant-based products fortified using wheat bran extract fermented with B12-producing food-grade was studied by applying a standard static model. At first, a culture of , fresh or heat-treated, was subjected to assays. Then, food ingredients or products were evaluated for their bioaccessibility: spray-dried wheat bran extract powder, pasta made with an extruder using fermented bran extract and breads made with spray-dried powder or with added cyanocobalamin.

Complete Genome Sequences and Methylome Analyses of Cutibacterium acnes subsp. Strains DSM 16379 and DSM 1897.

is a member of the normal human skin microbiome. However, it is also associated with skin disorders and persistent infections of orthopedic implants. Here, we announce complete genome sequences and methylomes of the subsp.

Growth Mode and Physiological State of Cells Prior to Biofilm Formation Affect Immune Evasion and Persistence of .

The present study investigated ATCC25923 surfaceomes (cell surface proteins) during prolonged growth by subjecting planktonic and biofilm cultures (initiated from exponential or stationary cells) to label-free quantitative surfaceomics and phenotypic confirmations. The abundance of adhesion, autolytic, hemolytic, and lipolytic proteins decreased over time in both growth modes, while an opposite trend was detected for many tricarboxylic acid (TCA) cycle, reactive oxygen species (ROS) scavenging, Fe-S repair, and peptidolytic moonlighters. In planktonic cells, these changes were accompanied by decreasing and increasing adherence to hydrophobic surface and fibronectin, respectively.

Red-Brown Pigmentation of Is Tied to Haemolytic Activity and Like Gene Cluster.

The novel genus encompasses species of industrial importance but also those associated with food spoilage. In particular, , , and play an important role in food fermentation, as biopreservatives, or as potential probiotics. Notably, and can cause brown spot defects in Swiss-type cheeses, which have been tied to the rhamnolipid pigment granadaene.

Co-fermentation of and in Wheat Bran for Production of Vitamin B12.

The present study investigated the effect of co-fermentation on vitamin B12 content and microbiological composition of wheat bran. DSM 20271 was used as the producer of vitamin while ATCC 14869 was selected to ensure the microbial safety of the bran dough. Fermentation trials were conducted in bioreactors to monitor and adjust the pH of the ferments.

Growth Mode and Carbon Source Impact the Surfaceome Dynamics of GG.

Bacterial biofilms have clear implications in disease and in food applications involving probiotics. Here, we show that switching the carbohydrate source from glucose to fructose increased the biofilm formation and the total surface-antigenicity of a well-known probiotic, GG. Surfaceomes (all cell surface-associated proteins) of GG cells grown with glucose and fructose in planktonic and biofilm cultures were identified and compared, which indicated carbohydrate source-dependent variations, especially during biofilm growth.

Acidipropionibacterium virtanenii sp. nov., isolated from malted barley.

A Gram-stain-positive, catalase-positive and pleomorphic rod organism was isolated from malted barley in Finland, classified initially by partial 16S rRNA gene sequencing and originally deposited in the VTT Culture Collection as a strain of Propionibacterium acidipropionici (currently Acidipropionibacterium acidipropionici). The subsequent comparison of the whole 16S rRNA gene with other representatives of the genus Acidipropionibacterium revealed that the strain belongs to a novel species, most closely related to Acidipropionibacterium microaerophilum and Acidipropionibacterium acidipropionici, with similarity values of 98.46 and 98.

Secretome profiling of Propionibacterium freudenreichii reveals highly variable responses even among the closely related strains.

This study compared the secretomes (proteins exported out of the cell) of Propionibacterium freudenreichii of different origin to identify plausible adaptation factors. Phylosecretomics indicated strain-specific variation in secretion of adhesins/invasins (SlpA, InlA), cell-wall hydrolysing (NlpC60 peptidase, transglycosylase), protective (RpfB) and moonlighting (DnaK, GroEL, GaPDH, IDH, ENO, ClpB) enzymes and/or proteins. Detailed secretome comparison suggested that one of the cereal strains (JS14) released a tip fimbrillin (FimB) in to the extracellular milieu, which was in line with the electron microscopy and genomic analyses, indicating the lack of surface-associated fimbrial-like structures, predicting a mutated type-2 fimbrial gene cluster (fimB-fimA-srtC2) and production of anchorless FimB.

production of active vitamin B12 in cereal matrices using .

The production of active vitamin B12 was investigated in aqueous cereal-based matrices with three strains of food-grade . Matrices prepared from malted barley flour (33% w/v; BM), barley flour (6%; BF), and wheat aleurone (15%; AM) were fermented. The effect of cobalt and the lower ligand 5,6-dimethylbenzimidazole (DMBI) or its natural precursors (riboflavin and nicotinamide) on active B12 production was evaluated.

De novo assembly of genomes from long sequence reads reveals uncharted territories of Propionibacterium freudenreichii.

Background: Propionibacterium freudenreichii is an industrially important bacterium granted the Generally Recognized as Safe (the GRAS) status, due to its long safe use in food bioprocesses. Despite the recognized role in the food industry and in the production of vitamin B12, as well as its documented health-promoting potential, P. freudenreichii remained poorly characterised at the genomic level.

Food-Like Growth Conditions Support Production of Active Vitamin B12 by 2067 without DMBI, the Lower Ligand Base, or Cobalt Supplementation.

is a traditional dairy bacterium and a producer of short chain fatty acids (propionic and acetic acids) as well as vitamin B12. In food applications, it is a promising organism for fortification with B12 vitamin since it is generally recognized as safe (GRAS) and it is able to synthesize biologically active form of the vitamin. In the present study, vitamin B12 and pseudovitamin biosynthesis by was monitored by UHPLC as a function of growth in food-like conditions using a medium mimicking cheese environment, without cobalt or 5,6-dimethylbenzimidazole (DMBI) supplementation.

Aspergillus flavus growth inhibition by Lactobacillus strains isolated from traditional fermented Kenyan milk and maize products.

Certain strains of lactic acid bacteria have been reported to inhibit fungal growth and may so be potential as biocontrol agents. In this study, 171 LAB strains were isolated from traditional fermented Kenyan milk and maize products and tested against aflatoxin-producing A. flavus fungi.

Ribosomal dimerization factor YfiA is the major protein synthesized after abrupt glucose depletion in Lactococcus lactis.

We analysed the response of the model bacterium Lactococcus lactis to abrupt depletion of glucose after several generations of exponential growth. Glucose depletion resulted in a drastic drop in the energy charge accompanied by an extremely low GTP level and an almost total arrest of protein synthesis. Strikingly, the cell prioritized the continued synthesis of a few proteins, of which the ribosomal dimerization factor YfiA was the most highly expressed.

The Cell Wall Polymer Lipoteichoic Acid Becomes Nonessential in Staphylococcus aureus Cells Lacking the ClpX Chaperone.

Unlabelled: Lipoteichoic acid (LTA) is an important cell wall component of Gram-positive bacteria and a promising target for the development of vaccines and antimicrobial compounds against Staphylococcus aureus Here we demonstrate that mutations in the conditionally essential ltaS (LTA synthase) gene arise spontaneously in an S. aureus mutant lacking the ClpX chaperone. A wide variety of ltaS mutations were selected, and among these, a substantial portion resulted in premature stop codons and other changes predicted to abolish LtaS synthesis.

Stress Physiology of Lactic Acid Bacteria.

Lactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field.

BluB/CobT2 fusion enzyme activity reveals mechanisms responsible for production of active form of vitamin B₁₂ by Propionibacterium freudenreichii.

Background: Propionibacterium freudenreichii is a food grade bacterium that has gained attention as a producer of appreciable amounts of cobalamin, a cobamide with activity of vitamin B12. Production of active form of vitamin is a prerequisite for attempts to naturally fortify foods with B12 by microbial fermentation. Active vitamin B12 is distinguished from the pseudovitamin by the presence of 5,6-dimethylbenzimidazole (DMBI) as the lower ligand.