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Food Research International (Ottawa,... Jun 2024Kefir is a traditional dairy beverage, usually made from cow or goat milk fermented with kefir grains, and has many health benefits. To elucidate the fermentation...
Kefir is a traditional dairy beverage, usually made from cow or goat milk fermented with kefir grains, and has many health benefits. To elucidate the fermentation patterns of animal milk kefirs during the fermentation process and find the optimal milk types, cow, camel, goat, and donkey milk were fermented with kefir grains for 0, 1, 3, 5, and 7 days. Volatile and non-volatile metabolites and microbial changes were dynamically monitored. The results showed that volatile flavor substances were massively elevated in four kefirs on days 1-3. Lipids and carbohydrates gradually decreased, while amino acids, small peptides, and tryptophan derivatives accumulated during fermentation in four kefirs. Besides, four kefirs had similar alterations in Lactobacillus and Acetobacter, while some distinctions existed in low-abundance bacteria. Association analysis of microorganisms and volatile and non-volatile metabolites also revealed the underlying fermentation mechanism. This study found that appropriately extending the fermentation time contributed to the accumulation of some functional nutrients. Furthermore, goat and donkey milk could be the better matrices for kefir fermentation.
Topics: Animals; Fermentation; Kefir; Goats; Cattle; Milk; Equidae; Volatile Organic Compounds; Taste; Camelus; Food Microbiology; Lactobacillus; Microbiota; Acetobacter; Amino Acids
PubMed: 38729687
DOI: 10.1016/j.foodres.2024.114305 -
Frontiers in Cellular and Infection... 2024High-fat diets (HFDs), a prevailing daily dietary style worldwide, induce chronic low-grade inflammation in the central nervous system and peripheral tissues, promoting...
High-fat diets (HFDs), a prevailing daily dietary style worldwide, induce chronic low-grade inflammation in the central nervous system and peripheral tissues, promoting a variety of diseases including pathologies associated with neuroinflammation. However, the mechanisms linking HFDs to inflammation are not entirely clear. Here, using a HFD model, we explored the mechanism of HFD-induced inflammation in remote tissues. We found that HFDs activated the IMD/NFκB immune pathway in the head through remodeling of the commensal gut bacteria. Removal of gut microbiota abolished such HFD-induced remote inflammatory response. Further experiments revealed that HFDs significantly increased the abundance of in the gut, and the re-association of this bacterium was sufficient to elicit inflammatory response in remote tissues. Mechanistically, produced a greater amount of peptidoglycan (PGN), a well-defined microbial molecular pattern that enters the circulation and remotely activates an inflammatory response. Our results thus show that HFDs trigger inflammation mediated by a bacterial molecular pattern that elicits host immune response.
Topics: Animals; Acetobacter; Diet, High-Fat; Disease Models, Animal; Drosophila melanogaster; Drosophila Proteins; Gastrointestinal Microbiome; Inflammation; NF-kappa B; Peptidoglycan; Signal Transduction
PubMed: 38716198
DOI: 10.3389/fcimb.2024.1347716 -
Journal of Agricultural and Food... May 2024The titer of the microbial fermentation products can be increased by enzyme engineering. l-Sorbosone dehydrogenase (SNDH) is a key enzyme in the production of...
The titer of the microbial fermentation products can be increased by enzyme engineering. l-Sorbosone dehydrogenase (SNDH) is a key enzyme in the production of 2-keto-l-gulonic acid (2-KLG), which is the precursor of vitamin C. Enhancing the activity of SNDH may have a positive impact on 2-KLG production. In this study, a computer-aided semirational design of SNDH was conducted. Based on the analysis of SNDH's substrate pocket and multiple sequence alignment, three modification strategies were established: (1) expanding the entrance of SNDH's substrate pocket, (2) engineering the residues within the substrate pocket, and (3) enhancing the electron transfer of SNDH. Finally, mutants S453A, L460V, and E471D were obtained, whose specific activity was increased by 20, 100, and 10%, respectively. In addition, the ability of WSH-004 to synthesize 2-KLG was improved by eliminating HO. This study provides mutant enzymes and metabolic engineering strategies for the microbial-fermentation-based production of 2-KLG.
Topics: Bacterial Proteins; Gluconobacter; Sugar Acids; Fermentation; Protein Engineering; Metabolic Engineering; Carbohydrate Dehydrogenases; Kinetics
PubMed: 38701424
DOI: 10.1021/acs.jafc.3c08365 -
Science (New York, N.Y.) Apr 2024The commensal microbiota of the mosquito gut plays a complex role in determining the vector competence for arboviruses. In this study, we identified a bacterium from the...
The commensal microbiota of the mosquito gut plays a complex role in determining the vector competence for arboviruses. In this study, we identified a bacterium from the gut of field mosquitoes named sp. YN46 (YN46) that rendered mosquitoes refractory to infection with dengue and Zika viruses. Inoculation of 1.6 × 10 colony forming units (CFUs) of YN46 into mosquitoes effectively prevents viral infection. Mechanistically, this bacterium secretes glucose dehydrogenase (GDH), which acidifies the gut lumen of fed mosquitoes, causing irreversible conformational changes in the flavivirus envelope protein that prevent viral entry into cells. In semifield conditions, YN46 exhibits effective transstadial transmission in field mosquitoes, which blocks transmission of dengue virus by newly emerged adult mosquitoes. The prevalence of YN46 is greater in mosquitoes from low-dengue areas (52.9 to ~91.7%) than in those from dengue-endemic regions (0 to ~6.7%). YN46 may offer an effective and safe lead for flavivirus biocontrol.
Topics: Animals; Aedes; Symbiosis; Dengue Virus; Mosquito Vectors; Zika Virus; Dengue; Gastrointestinal Microbiome; Acetobacteraceae; Female; Viral Envelope Proteins; Flavivirus; Zika Virus Infection
PubMed: 38669573
DOI: 10.1126/science.adn9524 -
FEMS Microbiology Ecology Apr 2024The Melipona gut microbes differ from other social bees, with the absence of crucial corbiculate core gut symbionts and the high occurrence of environmental strains. We...
The Melipona gut microbes differ from other social bees, with the absence of crucial corbiculate core gut symbionts and the high occurrence of environmental strains. We studied the microbial diversity and composition of three Melipona species and their honey to understand which strains are obtained by horizontal transmission (HT) from the pollination environment; or represent symbionts co-evolved with Melipona by HT from the hive/food stores or vertical transmission (VT) via social interactions. Bees harbored higher microbial alpha diversity and a different and more species-specific bacterial composition than honey. Otherwise, the fungal communities of bee and honey samples are less dissimilar. As expected, the core symbionts Snodgrassella and Gilliamella were absent in bees that had a prevalence of Lactobacillus Firm-5, environmental Lactobacillaceae, Bifidobacteriaceae and Acetobacteraceae. Also, Pectinatus and Floricoccus have habitat preferences for bees, putatively representing novel symbionts from the environment that co-evolved via VT among generations. Fructilactobacillus found in bees possibly had HT to bees from honey stores. Metschnikowia yeasts, consistent in all bees and honey samples, might have HT to bees from food stores. Similarly, Saccharomycetales might have HT from honey or plants/flowers to bees. This work contributes to the understanding of Melipona symbionts and their modes of transmission.
PubMed: 38650068
DOI: 10.1093/femsec/fiae063 -
Bioresource Technology Jun 2024Chemical production wastewater contains large amounts of organic solvents (OSs), which pose a significant threat to the environment. In this study, a 10 g·L styrene...
Chemical production wastewater contains large amounts of organic solvents (OSs), which pose a significant threat to the environment. In this study, a 10 g·L styrene oxide tolerant strain with broad-spectrum OSs tolerance was obtained via adaptive laboratory evolution. The mechanisms underlying the high OS tolerance of tolerant strain were investigated by integrating physiological, multi-omics, and genetic engineering analyses. Physiological changes are one of the main factors responsible for the high OS tolerance in mutant strains. Moreover, the P-type ATPase GOX_RS04415 and the LysR family transcriptional regulator GOX_RS04700 were also verified as critical genes for styrene oxide tolerance. The tolerance mechanisms of OSs can be used in biocatalytic chassis cell factories to synthesize compounds and degrade environmental pollutants. This study provides new insights into the mechanisms underlying the toxicological response to OS stress and offers potential targets for enhancing the solvent tolerance of G. oxydans.
Topics: Mutation; Epoxy Compounds; Gluconobacter oxydans; Solvents; Biodegradation, Environmental; Bacterial Proteins
PubMed: 38642663
DOI: 10.1016/j.biortech.2024.130674 -
Food Microbiology Aug 2024Sequence-based analysis of fermented foods and beverages' microbiomes offers insights into their impact on taste and consumer health. High-throughput metagenomics...
Sequence-based analysis of fermented foods and beverages' microbiomes offers insights into their impact on taste and consumer health. High-throughput metagenomics provide detailed taxonomic and functional community profiling, but bacterial and yeast genome reconstruction and mobile genetic elements tracking are to be improved. We established a pipeline for exploring fermented foods microbiomes using metagenomics coupled with chromosome conformation capture (Hi-C metagenomics). The approach was applied to analyze a collection of spontaneously fermented beers and ciders (n = 12). The Hi-C reads were used to reconstruct the metagenome-assembled genomes (MAGs) of bacteria and yeasts facilitating subsequent comparative genomic analysis, assembly scaffolding and exploration of "plasmid-bacteria" links. For a subset of beverages, yeasts were isolated and characterized phenotypically. The reconstructed Hi-C MAGs primarily belonged to the Lactobacillaceae family in beers, along with Acetobacteraceae and Enterobacteriaceae in ciders, exhibiting improved quality compared to conventional metagenomic MAGs. Comparative genomic analysis of Lactobacillaceae Hi-C MAGs revealed clustering by niche and suggested genetic determinants of survival and probiotic potential. For Pediococcus damnosus, Hi-C-based networks of contigs enabled linking bacteria with plasmids. Analyzing phylogeny and accessory genes in the context of known reference genomes offered insights into the niche specialization of beer lactobacilli. The subspecies-level diversity of cider Tatumella spp. was disentangled using a Hi-C-based graph. We obtained highly complete yeast Hi-C MAGs primarily represented by Brettanomyces and Saccharomyces, with Hi-C-facilitated chromosome-level genome assembly for the former. Utilizing Hi-C metagenomics to unravel the genomic content of individual species can provide a deeper understanding of the ecological interactions within the food microbiome, aid in bioprospecting beneficial microorganisms, improving quality control and improving innovative fermented products.
Topics: Saccharomyces cerevisiae; Beer; Bacteria; Plasmids; Saccharomyces; Metagenome; Metagenomics; Enterobacteriaceae
PubMed: 38637082
DOI: 10.1016/j.fm.2024.104520 -
Molecular Biology Reports Apr 2024Komagataeibacter nataicola (K. nataicola) is a gram-negative acetic acid bacterium that produces natural bacterial cellulose (BC) as a fermentation product under acidic...
BACKGROUND
Komagataeibacter nataicola (K. nataicola) is a gram-negative acetic acid bacterium that produces natural bacterial cellulose (BC) as a fermentation product under acidic conditions. The goal of this work was to study the complete genome of K. nataicola and gain insight into the functional genes in K. nataicola that are responsible for BC synthesis in acidic environments.
METHODS AND RESULT
The pure culture of K. nataicola was obtained from yeast-glucose-calcium carbonate (YGC) agar, followed by genomic DNA extraction, and subjected to whole genome sequencing on a Nanopore flongle flow cell. The genome of K. nataicola consists of a 3,767,936 bp chromosome with six contigs and 4,557 protein coding sequences. The maximum likelihood phylogenetic tree and average nucleotide identity analysis confirmed that the bacterial isolate was K. nataicola. The gene annotation via RAST server discovered the presence of cellulose synthase, along with three genes associated with lactate utilization and eight genes involved in lactate fermentation that could potentially contribute to the increase in acid concentration during BC synthesis.
CONCLUSION
A more comprehensive genome study of K. nataicola may shed light into biological pathway in BC productivity as well as benefit the analysis of metabolites generated and understanding of biological and chemical interactions in BC production later.
Topics: Food Loss and Waste; Cellulose; Phylogeny; Food; Refuse Disposal; Whole Genome Sequencing; Lactates; Acetobacteraceae
PubMed: 38600404
DOI: 10.1007/s11033-024-09492-8 -
Journal of Food Science May 2024It is crucial to clarify the stability of Kombucha in the manufacture and storage stages due to the extensive study on the fermented products of Kombucha and the...
It is crucial to clarify the stability of Kombucha in the manufacture and storage stages due to the extensive study on the fermented products of Kombucha and the increase in the use of bacterial cellulose (BC). This study aimed to evaluate the stability of Kombucha in different manufacturing and storage temperatures within a certain time period. The stability of microorganisms and BC in Kombucha was investigated through regular replacement with the tea media at 28 and 25°C for manufacture, and the storage temperature of Kombucha was at 25, 4, and -20°C. Morphological observations of the BC in Kombucha ended at 28 and 25°C for manufacture and storage were performed using atomic force microscopy (AFM) before inoculation. The viable cell counts and AFM results showed that the stability of Kombucha during manufacture was better at 28°C than at 25°C, with higher microbial viability and BC productivity in the former at the time of manufacture, whereas 25°C was more favorable for the stability of Kombucha during storage. At the same temperature of 25°C, the manufacturing practice improved the microbial viability and BC stability compared with storage; the pH value of Kombucha was lower, and the dry weight of BC was higher during storage compared with manufacture. The maximum BC water holding capacity (97.16%) was maintained by storage at 4°C on day 63, and the maximum BC swelling rate (56.92%) was observed after storage at -20°C on day 7. The research was conducted to provide reference information for applying Kombucha and its BC in food and development in other industries.
Topics: Cellulose; Temperature; Fermentation; Food Storage; Food Microbiology; Kombucha Tea; Hydrogen-Ion Concentration; Microbial Viability; Acetobacteraceae; Food Handling
PubMed: 38591324
DOI: 10.1111/1750-3841.16975 -
Cell Reports Apr 2024Microbial invasions underlie host-microbe interactions resulting in pathogenesis and probiotic colonization. In this study, we explore the effects of the microbiome on...
Microbial invasions underlie host-microbe interactions resulting in pathogenesis and probiotic colonization. In this study, we explore the effects of the microbiome on microbial invasion in Drosophila melanogaster. We demonstrate that gut microbes Lactiplantibacillus plantarum and Acetobacter tropicalis improve survival and lead to a reduction in microbial burden during infection. Using a microbial interaction assay, we report that L. plantarum inhibits the growth of invasive bacteria, while A. tropicalis reduces this inhibition. We further show that inhibition by L. plantarum is linked to its ability to acidify its environment via lactic acid production by lactate dehydrogenase, while A. tropicalis diminishes the inhibition by quenching acids. We propose that acid from the microbiome is a gatekeeper to microbial invasions, as only microbes capable of tolerating acidic environments can colonize the host. The methods and findings described herein will add to the growing breadth of tools to study microbe-microbe interactions in broad contexts.
Topics: Animals; Drosophila melanogaster; Microbiota; Acetobacter; Gastrointestinal Microbiome; Lactobacillus plantarum; Hydrogen-Ion Concentration; Lactic Acid
PubMed: 38583152
DOI: 10.1016/j.celrep.2024.114087